ALBERT

Description: Publication date: September 2015 Source: Journal of Hydrology: Regional Studies, Volume 4, Part B Author(s): Alberto Pistocchi, Costanza Calzolari, Francesco Malucelli, Fabrizio Ungaro Study region The plains of Emilia Romagna, Italy. Study focus Urban expansion is among the main causes of increase in flood frequency and intensity in small rural catchments in Europe, and our study region is paradigmatic in this respect. We present here a regional screening-level assessment of soil sealing impacts in terms of increased flood peak discharges and flooding volumes on the secondary drainage network of the plains. We estimate flood peak discharges and flooding volumes through a simple kinematic model with runoff coefficients for the land use of 2008 and 1976. Additionally, we calculate an equivalent compensatory flood detention volume that would enable preserving flood peak discharges as prior to soil sealing (principle of “hydraulic invariance”). The proposed approach is simple and readily applicable to any region facing similar issues, for screening-level assessment of flood hazards over an extended stream network. New hydrological insights for the region The analysis highlights a significant increase in flood hazards throughout the secondary stream network. The impact. Widespread and relatively uniform, is more apparent in smaller catchments and in the case of more permeable soils. This demands retrofitting of the majority of the drainage network and/or significantly higher costs from flooding damages. The analysis suggests that costs of additional flooding after soil sealing may be higher than those of soil sealing impacts compensation through flood detention (hydraulic invariance).

Description: Publication date: September 2015 Source: Journal of Hydrology: Regional Studies, Volume 4, Part B Author(s): M.A. Sarr, O. Seidou, Y. Tramblay, S. El Adlouni Study region The study considers six precipitation stations located in Senegal, West Africa. Senegal is located in the Sahel, an area that is threatened by climate variability and change. Both droughts and extreme rainfall have been an issue in recent years. Study focus Two different statistical downscaling techniques were applied to the outputs of four regional climate models at six selected precipitation stations in Senegal. First, the delta-change method was applied to the mean annual precipitation as well as the 5, 10, 20, 50 and 100-year return period daily precipitation events. Second, a quantile–quantile transformation (QQ) was used to downscale the monthly distributions of precipitation simulated by regional climate models (RCMs). The 5, 10, 20, 50 and 100-year daily precipitation events were afterward calculated. All extreme events were calculated assuming that maximum annual daily precipitations follow the generalized extreme value (GEV) distribution. The two-sided Kolmogorov–Smirnov (KS) test was finally used to assess the performance of the quantile–quantile transformation as well as the GEV distribution fit for the annual maximum daily precipitation. New hydrological insights for the region Results show that the two downscaling techniques generally agree on the direction of the change when applied to the outputs of same RCM, but some cases lead to very different projections of the direction and magnitude of the change. Projected changes indicate a decline in mean precipitation except for one RCM over one region in Senegal. Projected changes in extreme precipitations are not consistent across stations and return periods. The choice of the downscaling technique has more effect on the estimation of extreme daily precipitations of return period equal or greater than ten years than the choice of the climate models.

Description: Publication date: September 2015 Source: Journal of Hydrology: Regional Studies, Volume 4, Part B Author(s): J.S. Lessels, T.F.A. Bishop Study region South eastern Australia. Study focus This region is characterised with rainfall events that are associated with large exports of nutrients and sediments. Many water quality monitoring schemes use a form of event-based sampling to quantify these exports. Previous water quality studies that have evaluated different sampling schemes often rely on continuously monitored water quality data. However, many catchment authorities only have access to limited historical data which consists of event-based and monthly routine samples. Therefore there is a need to develop a method that assesses the importance of sampling events using information from limited historical data. This work presents a simulation based approach using unconditional simulation based on historical stream discharge. Such an approach offers site-specific information on optimal sampling schemes. A linear mixed model is used to model the relationship between total phosphorus and stream discharge and the auto-correlation of total phosphorus. New hydrological insights for the region The inclusion of event-based sampling improved annual load estimates of all sites with a maximum RMSE difference of 16.11 tonnes between event-based and routine sampling. Based on the accuracy of annual loads, event-based sampling was found to be more important in catchments with a large relief and high annual rainfall in this region. Using this approach, different sampling schemes can be compared based on limited historical data.

Description: Publication date: September 2015 Source: Journal of Hydrology: Regional Studies, Volume 4, Part B Author(s): Hayet Chihi, Ghislain de Marsily, Habib Belayouni, Houcine Yahyaoui Study region “Jeffara de Medenine” aquifer system in south-eastern Tunisia. Study focus This study investigates the role of fault structures in the distribution of hydrogeochemical facies and groundwater compartmentalization for the aquifer system. New hydrological insights for the region The proposed methodology, including seismic structural study, hierarchical cluster analysis and geostatistical methods, allowed an efficient multi-element characterization of the spatial patterns of the structural elements in the aquifers and of the hydrogeological parameters used in a spatial cross-correlation to explore the dependence of the geochemical properties in each “geochemical population” on the hosting structural compartment to delineate the different geochemical compartments. The tectonic studies showed that the lateral extent of the aquifers is controlled by normal faults. The multivariate statistical analysis revealed a strong spatial coherence between hydrogeochemical facies clustering and the reservoir compartments at both large and small scales. The kriged maps of major-ion concentrations and of total dissolved solids in the aquifers were then analyzed and compared with the reservoir facies distribution for each compartment, the geometric characteristics of the aquifer, and the piezometric level trends. This allowed to characterize the hydraulic behavior of the Medenine fault and to understand the underlying physical and chemical processes having led to the spatial distribution of the geochemical properties, and thus, the hydrogeochemical functioning of the aquifers.

Description: Publication date: September 2015 Source: Journal of Hydrology: Regional Studies, Volume 4, Part B Author(s): Marnie L. Atkins, Isaac R. Santos, Damien T. Maher Study region This study investigates dissolved methane distribution in groundwater from the Richmond River Catchment (New South Wales, Australia) before proposed coal seam gas (CSG, or coal bed methane) development. Study focus Unconventional gas exploration has rapidly expanded in recent years. However, the impact of these operations on groundwater systems is poorly understood. A total of 91 groundwater samples were analyzed from 6 geological units. Our observations act as regional baseline research prior to CSG extraction and may assist with long term impact assessment. New hydrological insights for the region Methane was found in all geological units ranging between 0.26 and 4427 μg L −1 (median 10.68 μg L −1 ). Median methane concentrations were highest in chloride-type groundwater (13.26 μg L −1 , n = 58) while bicarbonate-type groundwater had lower concentrations (3.71 μg L −1 ). Groundwater from alluvial sediments had significantly higher median methane concentrations (91.46 μg L −1 ) than groundwater from both the basalt aquifers (0.7 μg L −1 ) and bedrock aquifers (4.63 μg L −1 ); indicating geology was a major driver of methane distribution. Methane carbon stable isotope ratios ranged from –90.9‰ to –29.5‰, suggesting a biogenic origin with some methane oxidation. No significant correlations were observed between methane concentrations and redox indicators (nitrate, manganese, iron and sulphate) except between iron and methane in the Lismore Basalt ( r 2 = 0.66, p 〈 0.001), implying redox conditions were not the main predictor of methane distribution.

Description: Publication date: September 2015 Source: Journal of Hydrology: Regional Studies, Volume 4, Part B Author(s): Z. Zomlot, B. Verbeiren, M. Huysmans, O. Batelaan Study focus Groundwater is of strategic importance. The accurate estimation of groundwater recharge and assessing the fundamental controlling factors are therefore of utmost importance to protect groundwater systems. We used the spatially-distributed water-balance model WetSpass to estimate long-term average recharge in Flanders. We validated recharge rates with base flow estimates of 67 daily stream flow records using the hydrograph analyses. To this end we performed principal component analysis, multiple linear regression analysis and relative importance analysis to assess the controlling factors of the spatial variation of recharge and base flow with the influencing watershed characteristics. New hydrological insights for the region The average resulting recharge is 235 mm/year and occurs mainly in winter. The overall moderate correlation between base flow estimates and modeled recharge rates indicates that base flow is a reasonable proxy of recharge. Groundwater recharge variation was explained in order of importance by precipitation, soil texture and vegetation cover; while base flow variation was strongly controlled by vegetation cover and groundwater depth. The results of this study highlight the important role of spatial variables in estimation of recharge and base flow. In addition, the prominent role of vegetation makes clear the potential importance of land-use changes on recharge and hence the need to include a proper strategy for land-use change in sustainable management of groundwater resources.

Description: Publication date: September 2015 Source: Journal of Hydrology: Regional Studies, Volume 4, Part B Author(s): B. Ibrahim, D. Wisser, B. Barry, T. Fowe, A. Aduna Study region Hydrological observation networks in the West African region are not dense and reliable. Furthermore, the few available discharge data often present significant gaps. The Volta basin, the second largest transboundary basin in the region, is a typical example of a basin with inadequate hydrological networks. Study focus In this study, a prediction approach to determine monthly discharge in ungauged watersheds is developed. The approach is based on the calibration of two conceptual models for gauged watersheds and an estimation of models’ parameters from the physical and climatic characteristics of the watersheds. The models’ parameters were determined for each ungauged watershed through two different methods: the multiple linear regressions and the kriging method. The two methods were first validated on five gauged watersheds and then applied to the three ungauged watersheds. New hydrological insights for the region The application of the two hydrological models on the eight watersheds helped to produce relevant monthly runoff and to establish the annual hydrological balances from 1970 to 2000 for both gauged and ungauged watersheds. The developed method in this study could therefore help estimate runoff time series, which are of crucial importance when it comes to design hydraulic structures such as small reservoirs.

Description: Publication date: Available online 14 August 2015 Source: Journal of Hydrology: Regional Studies Author(s): Mayank Shekhar, Amalava Bhattacharyya Study region Zemu Chuu (river), Lachen, North Sikkim, Eastern Himalaya India. Study focus Using tree-ring data of fir ( Abies densa ) the temporal variation of 222 years January–April mean discharge of Zemu Chuu, upper reaches of the Teesta River at Lachen, North Sikkim Eastern Himalaya was investigated. This was based on linear regression reconstruction model which explained variance of 50.1% during calibration period (AD 1976–1996). The model was verified by reduction of error (RE), sign test (ST), product mean test (Pmt), root mean square error (RMSE) and Durbin–Watson test (DW). The RE never falls below zero suggesting the model had explanatory power over the entire period of reconstruction. New hydrological insights for the region The explored strong relationship between tree ring records and instrumental data enable to develop mean January–April months (premonsoon) river discharge of Zemu Chuu from remote area of Sikkim. Reconstructed data reveals high stream-flow when it is more than the mean plus one standard deviation and as low when flow is less than the mean minus one standard deviation. There were such 23 high discharge and 21 extremely low years over the past AD 1775–1996. This premonsoon reconstruction of river flow would be of great significance when scarcity of water is acute in the North East Himalaya.

Description: Publication date: September 2015 Source: Journal of Hydrology: Regional Studies, Volume 4, Part B Author(s): Jonathan A. Warrick, John M. Melack, Blair M. Goodridge Study region Coastal watersheds of southern California, United States. Study focus We sought to better understand the rates and variability of suspended-sediment discharge from small coastal watersheds (〈100 km 2 ) of California. Suspended-sediment concentrations and stream discharge were measured with automated samplers near the mouths of four small watersheds (10–56 km 2 ). New hydrological insights for the region The watersheds were found to have suspended-sediment concentrations that extended over five orders of magnitude (1 to over 100,000 mg L −1 ). Sediment concentrations were weakly correlated with discharge ( r 2 = 0.10–0.25), and four types of hysteresis patterns were observed during high flow events (clockwise, counterclockwise, no hysteresis, and complex). Annual sediment yields varied by 400-fold across the four watersheds (e.g., 5–2100 t km −2 yr −1 during the 2003–2006 water years), and sediment discharge was measurably elevated in one watershed that was partially burned by a late summer wildfire. Dozens of high flow events provided evidence that suspended-sediment yields were generally related to peak stream discharge and event-based precipitation, although these relationships were not consistent across the watersheds. This suggests that watersheds smaller than 100 km 2 can provide large – and therefore important – fluxes of sediment to the coast, but that simple techniques to estimate sediment loads, such as sediment rating curves, hydrologic regressions, and extrapolation using global sediment yield relationships that include watershed area as a primary factor, may provide poor results. Graphical abstract

Description: Publication date: September 2015 Source: Journal of Hydrology: Regional Studies, Volume 4, Part B Author(s): Chris C. Gianfagna, Chris E. Johnson, David G. Chandler, Charlie Hofmann Study region The Catskills region of New York State is largely forested and dominated hydrologically by stream watersheds with few natural lakes. The area experiences intensive water resources management and ecosystem monitoring due to its strategic role as the principal water supply for New York City. Study focus We analyzed average daily flows in nested and non-nested pairs of gaged watersheds in the Catskills to assess whether daily flow in ungaged watersheds can be calculated based on watershed area ratios. New hydrological insights for the region Watershed area ratio was the most important basin parameter for estimating flow at upstream sites based on downstream flow. The area ratio alone explained 93% of the variance in the slopes of relationships between upstream and downstream flows. Regression analysis indicated that flow at any upstream point can be estimated by multiplying the flow at a downstream reference gage by the watershed area ratio. This method accurately predicted upstream flows at area ratios as low as 0.005. We also observed a very strong relationship ( R 2 = 0.79) between area ratio and flow–flow slopes in non-nested catchments. Our results indicate that a simple flow estimation method based on watershed area ratios is justifiable, and indeed preferred, for the estimation of daily streamflow in ungaged watersheds in the Catskills region.

Description: Publication date: September 2015 Source: Journal of Hydrology: Regional Studies, Volume 4, Part B Author(s): Alfonso Rivera Study region Canada–USA border. Study focus Since 2005, Canada has followed international developments in transboundary groundwater issues in cooperation with its southern neighbor the United States (USA) within the Internationally Shared Aquifer Resources Management Initiative (ISARM) of UNESCO. As a result, 10 Transboundary Aquifer Systems (TAS) were identified along the border between Canada and the USA. This study is an extensive review of the current state of the 10 TAS. Documentation of scientifically-based knowledge on TAS is an important step in identifying potential issues in policies that might be adopted to address shared water-resource issues. New hydrological insights for the region This analysis emphasizes the need for more scientific data, widespread education and training, and a more clearly defined governments’ role to manage groundwater at the international level. The study reviews the current legal framework and summarises the current scientific knowledge for the TAS with respect to the hydrologic and geologic framework as well as some of the major drivers for supply and demand. It also describes the links, approach and relevance of studies on the TAS to the UN Law of Transboundary Aquifers and on how these might fit in the regional strategy for the assessment and management of the TAS. Clear communication, shared knowledge and common objectives in the management of TAS will prepare the countries for future negotiations and cooperative binational programs.

Description: Publication date: September 2015 Source: Journal of Hydrology: Regional Studies, Volume 4, Part B Author(s): Brioch Hemmings, Daren Gooddy, Fiona Whitaker, W. George Darling, Alia Jasim, Joachim Gottsmann Study region Montserrat, Lesser Antilles, Caribbean. Study focus Analysis of δ 2 H and δ 18 O isotopes, and chlorofluorocarbon (CFC) anthropogenic tracers in Montserrat groundwater provides insights into the age and provenance of the spring waters. New hydrological insights δ 2 H and δ 18 O analysis indicates uniform recharge elevations for groundwaters on Montserrat. CFC-11 and CFC-12 analysis reveals age differences between isotopically similar, high elevation springs and low elevation aquifer waters. Low CFC concentrations within a confined low elevation aquifer suggest water ages of ∼45 years. High CFC concentrations in the northern and western springs are explained by rapid infiltration of cool (high CFC concentration) rainfall into saturated compartments, with flow through the vadose zone to the phreatic zone dominated by compartment flow. Lower CFC concentrations in a number of aligned warmer springs suggest a contribution from older, warmer waters from depth. Temperatures and CFC concentrations indicate older component supply rates of up to 8 L/s to the highest yielding spring on Centre Hills, with contributions of up to 75% in the warmest spring waters.

Description: Publication date: March 2015 Source: Journal of Hydrology: Regional Studies, Volume 3, Supplement 1

Description: Publication date: March 2015 Source: Journal of Hydrology: Regional Studies, Volume 3, Supplement 1

Description: Publication date: March 2015 Source: Journal of Hydrology: Regional Studies, Volume 3, Supplement 1

Description: Publication date: March 2015 Source: Journal of Hydrology: Regional Studies, Volume 3, Supplement 1

Description: Publication date: Available online 3 April 2015 Source: Journal of Hydrology: Regional Studies Author(s): A. Shahul Hameed , T.R. Resmi , S. Suraj , C. Unnikrishnan Warrier , M. Sudheesh , R.D. Deshpande Study region The Chaliyar river basin, Kerala State, India. Study focus Detailed understanding about spatio-temporal variation in the interaction and exchange of water between surface and sub-surface reservoirs is important for effective watershed management. Spatio-temporal variations in the oxygen isotopic composition ( δ 18 O) were used to understand the interaction between groundwater and river water, and to estimate the groundwater recharge from river water in the Chaliyar river basin. New hydrological insights for the region Based on the spatio-temporal variation in δ 18 O values of river and groundwater and fluctuation in ground water levels, following important inferences are made: (1) estimated river water contribution to post-monsoon groundwater recharge is ∼16% in the lowland coastal area of the Chaliyar river basin and 29% in midland region; (2) northeast winter monsoon rains contribute to the groundwater of Chaliyar river basin only in an insignificant manner, and with a delayed response; (3) unlike river water samples which exhibit both seasonal and spatial variation of more than 3‰, the groundwater samples vary only marginally (∼1‰) between the seasons and across the physiographic zones; (4) groundwater samples exhibit inverse altitude gradient in δ 18 O values in the highland zone, in all the three seasons. This may be due to flow of the isotopically depleted groundwater down the gradient and evaporation of residual water in the upper reaches of the basin.

Description: Publication date: March 2015 Source: Journal of Hydrology: Regional Studies, Volume 3, Supplement 1 Author(s): Ashish Sharma

Description: Publication date: Available online 16 May 2015 Source: Journal of Hydrology: Regional Studies Author(s): E.H. Elias , A. Rango , C.M. Steele , J.F. Mejia , R. Smith Study region Upper Rio Grande, Colorado and New Mexico, USA. Study focus Climate change is predicted to further limit the water availability of the arid southwestern U.S. We use the snowmelt runoff model to evaluate impacts of climate change on snow covered area (SCA), streamflow timing and runoff volume. Simulations investigate four future conditions using models downscaled to existing climate stations. Twenty-four subbasins of the Upper Rio Grande containing appreciable snowmelt and a long-term gauging station are simulated. New hydrological insights for the region Future annual volume is 193–204 million m 3 more to 448–476 million m 3 less than the pre-climate change value of 2688 million m 3 . There is disparity between increased volume in wetter simulations (+7%) and decreased volume (−18%) in drier simulations. SCA on 1 April reduced by approximately 50% in all but the warmer/wetter climate. Peak flow is 14–24 days early in the future climates. Among the 24 subbasins there is considerable range in mean melt season SCA (−40% to −100%), total volume change (−30% to +57%) and runoff timing advancement indicating that climate change is best evaluated at the subbasin scale. Daily hydrographs show higher streamflow in March and April, but less from mid-May until the end of the water year. The large decrease in volume in May, June and July will compound water management challenges in the region.

Description: Publication date: March 2015 Source: Journal of Hydrology: Regional Studies, Volume 3, Supplement 1 Author(s): Mohammad Kamruzzaman

Description: Publication date: March 2015 Source: Journal of Hydrology: Regional Studies, Volume 3, Supplement 1

Description: Publication date: March 2015 Source: Journal of Hydrology: Regional Studies, Volume 3, Supplement 1

Description: Publication date: March 2015 Source: Journal of Hydrology: Regional Studies, Volume 3 Author(s): Jean-Michel Lemieux , Jalil Hassaoui , John Molson , René Therrien , Pierre Therrien , Michel Chouteau , Michel Ouellet Study region This study is conducted in the Magdalen Islands (Québec, Canada), a small archipelago located in the Gulf of St. Lawrence. Study focus This work was undertaken to support the design of a long-term groundwater monitoring network and for the sustainable management of groundwater resources. This study relies mostly on the compilation of existing data, but additional field work has also been carried out, allowing for the first time in the Magdalen Islands, direct observation of the depth and shape of the transition zone between freshwater and seawater under natural conditions. Simulations were conducted along a 2D cross-section on Grande Entrée Island in order to assess the individual and combined impacts of sea-level rise, coastal erosion and decreased groundwater recharge on the position of the saltwater–freshwater interface. The simulations were performed considering variable-density flow and solute transport under saturated-unsaturated conditions. The model was driven by observed and projected climate change scenarios to 2040 for the Magdalen Islands. New hydrological insights for the region The simulation results show that among the three impacts considered, the most important is sea-level rise, followed by decreasing groundwater recharge and coastal erosion. When combined, these impacts cause the saltwater–freshwater interface to migrate inland over a distance of 37 m and to rise by 6.5 m near the coast to 3.1 m further inland, over a 28-year period.

Description: Publication date: March 2015 Source: Journal of Hydrology: Regional Studies, Volume 3 Author(s): M.A. Pascolini-Campbell , Richard Seager , David S. Gutzler , Benjamin I. Cook , Daniel Griffin Study region The Gila River, New Mexico, is characterized by two peaks in streamflow: one in the winter–spring (December–May), and summer (August–September). The region is influenced both by Pacific SST variability as well as the North American Monsoon. Study focus The mechanisms responsible for the variability of the winter–spring and summer streamflow peaks are investigated by correlation of streamflow with precipitation and sea surface temperature for 1928–2012. Decadal variability in the flow record is examined for a longer term perspective on Gila River streamflow using tree ring-based reconstructions of the Palmer Drought Severity Index (PDSI) and the Standardized Precipitation Index (SPI). New hydrological insights for the region Results indicate a strong influence of winter–spring precipitation and Pacific SST anomalies on the winter–spring streamflow, with El Niño conditions in the Pacific causing increased precipitation and streamflow. Decadal Pacific variability helps explain the transition from high winter flow in the late 20th century to lower flows in the most recent decade. The summer streamflow has a somewhat weaker correlation with precipitation and Pacific SST than the winter–spring streamflow. Its variability is more likely influenced by local North American Monsoon precipitation variability. PDSI and SPI reconstructions indicate much more severe and extended periods of droughts and pluvials in past centuries as well as periods of concurrent winter and summer drought.

Description: Publication date: March 2015 Source: Journal of Hydrology: Regional Studies, Volume 3 Author(s): Tsou Jaw , Jialun Li , Kuo-lin Hsu , Soroosh Sorooshian , Fatima Driouech Study region Morocco (excluding Western Sahara). Study focus This study evaluated Moroccan precipitation, dynamically downscaled (0.18-degree) from three runs of the studied GCM ECHAM5/MPI-OM, under the present-day (1971–2000/20C3M) and future (2036–2065/A1B) climate scenarios. The spatial and quantitative properties of the downscaled precipitation were evaluated by a verified, fine-resolution reference. The effectiveness of the hydrologic responses, driven by the downscaled precipitation, was further evaluated for the study region over the upstream watershed of Oum er Rbia River located in Central Morocco. New hydrological insights for the region The raw downscaling runs reasonably featured the spatial properties but quantitatively misrepresented the mean and extreme intensities of present-day precipitation. Two proposed bias correction approaches, namely stationary Quantile-Mapping (QM) and non-stationary Equidistant CDF Matching model (EDCDFm), successfully reduced the system biases existing in the raw downscaling runs. However, both raw and corrected runs projected great diversity in terms of the quantity of future precipitation. Hydrologic simulations performed by a well-calibrated Variable Infiltration Capacity model successfully reproduced the present-day streamflow. The driven flows were identified highly correlated with the effectiveness of the downscaled precipitation. The future flows were projected to be markedly diverse, mainly due to the varied precipitation projections. Two of the three flow simulation runs projected slight to severe drying scenarios, while another projected an opposite trend for the evaluated future period.

Description: Publication date: March 2015 Source: Journal of Hydrology: Regional Studies, Volume 3 Author(s): Megersa Olumana Dinka , Willibald Loiskandl , Julius Musyoka Ndambuki Study region The Matahara region is located in the East Showa zone of Oromiya regional state (Ethiopia). Matahra Sugar Estate and Lake Basaka (highly saline, alkaline and sodic lake) are situated within the flat plains of Matahara region. The area is vulnerable to the occurrences of various tectonic and volcanic activities due to its location in the upper most part of the Main Ethiopian Rift Valley region. Study focus In this study, the hydrochemical properties of different surface water and groundwater bodies available at Matahara region have been characterized for quality compositions. Water samples were collected from different water sources and analyzed for important major quality parameters following standard test procedures. Other chemical indices were derived from the measured quality parameters. The potential sources of minerals were suggested for each of the considered water sources based on their quality characteristics. New hydrological insights for the region Overall, the study result elucidates that the chemical composition of different water bodies are due to natural processes and/or anthropogenic activities within the region. The local anthropogenic processes could be discharges from factory, domestic sewage and farming activities. Some of the water types are found to have relatively higher concentration of dissolved constituents. Irrigation waters have almost equal chemical compositions, indicating their hydrochemical sources are almost the same. Most of the concentrations are relatively high in Lake Basaka, groundwater and hot springs. It is easy to imagine the potential damaging effects of such quality waters on crop production, soil properties and environment of the region.

Description: Publication date: March 2015 Source: Journal of Hydrology: Regional Studies, Volume 3 Author(s): Julianne Hagarty , David Azanu , Bernadette Atosona , Ray Voegborlo , Erica A.H. Smithwick , Kamini Singha Study region Buruli ulcer, an emerging disease caused by Mycobacterium ulcerans , largely affects poor rural populations in tropical countries. The environmental niche that supports this necrotizing bacterium is unclear. Here, water samples were collected from five communities within Ghana in the rainy season in 2011: four in the southern part of Ghana (three disease-endemic communities: Pokukrom, Betenase, and Ayanfuri, and one control: Kedadwen) and one non-endemic community (Nangruma) in the north. Study focus Past studies of Buruli ulcer conclude that water quality is, in some way, closely related to the transmission of this disease. This work serves as a first step to explore links between Buruli ulcer incidence and water quality. More broadly, this research works toward identifying the environmental niche for M. ulcerans , providing characterization of water bodies hazardous to human health in at-risk communities. New hydrological insights Trace metals, thought to aid in the preferential growth of M. ulcerans , are present in higher concentrations in mining pits and stagnant pools than in other tested water bodies. Arsenic in particular could serve as a double threat for BU incidence: it could support the growth of M. ulcerans while suppressing immune systems, making the population more susceptible to disease. Few other differences between endemic and non-endemic communities exist, implying other variables such as human behavior may also control the onset of Buruli ulcer.

Description: Publication date: Available online 18 April 2015 Source: Journal of Hydrology: Regional Studies Author(s): Fabrice Papa , Frédéric Frappart , Yoann Malbeteau , Mohammad Shamsudduha , Venugopal Vuruputur , Muddu Sekhar , Guillaume Ramillien , Catherine Prigent , Filipe Aires , Rajesh Kumar Pandey , Sujit Bala , Stephane Calmant Study region The Ganges–Brahmaputra (GB), a major river basin of the Indian Sub-Continent (ISC), is the host of more than 700 millions people. Study focus In addition to monsoons and strong climate variability, GB is facing growing demands for freshwater availability by a continually growing population and rapidly developing of agricultural and industrial sectors. The management of water resources is thus of highest priority and, in the context of current over-abstraction of groundwater, accurate estimates of terrestrial freshwater storage are essential. We propose a multi-satellite approach to estimate surface freshwater storage (SWS) and subsurface water storage (SSWS, groundwater + soil moisture) variations over GB. New hydrological insights Basin-scale monthly SWS variations for the period 2003–2007 show a mean annual amplitude of ∼410 km 3 , contributing to about 45% of the Gravity Recovery And Climate Experiment (GRACE)-derived total water storage variations (TWS). During the drought-like conditions in 2006, we estimate that the SWS deficit over the entire GB basin in July–August–September was about 30% as compared to other years. The SWS variations are then used to decompose the GB GRACE-derived TWS and isolate the variations of SSWS whose mean annual amplitude is estimated to be ∼550 km 3 . This new dataset of water storage variations represent an unprecedented source of information for hydrological and climate modeling studies of the ISC.

Description: Publication date: Available online 7 April 2015 Source: Journal of Hydrology: Regional Studies Author(s): Swati Verma , Abhijit Mukherjee , Runti Choudhury , Chandan Mahanta Study region Brahmaputra River basin, India. Study focus The present study deciphers the groundwater solute chemistry and arsenic (As) enrichment in the shallow aquifers of the study region. Four different geomorphologic units, e.g. piedmont (PD), older alluvium of river Brahmaputra and its tributaries (OA), active alluvium of river Brahmaputra and its tributaries (YA) and river channel deposits (RCD) were identified. More than 62% of all groundwater samples collected have dissolved As >0.01 mg/L, whereas about 87% of groundwater samples in OA terrain are enriched with As, which draws a distinct difference from the adjoining Gangetic aquifers. New hydrological insights for the region Most groundwater solutes of RCD and YA terrains were derived from both silicate weathering and carbonate dissolution, while silicate weathering process dominates the solute contribution in OA groundwater. Groundwater samples from all terrains are postoxic with mean pe values between Fe(III) and As(V)–As(III) reductive transition. While, reductive dissolution of (Fe–Mn)OOH is the dominant mechanism of As mobilization in RCD and YA aquifers, As in OA and PD aquifers could be mobilized by combined effect of pH dependent sorption and competitive ion exchange. The present study focuses on the major ion chemistry as well as the chemistry of the redox sensitive solutes of the groundwater in different geomorphic settings and their links to arsenic mobilization in groundwater.

Description: Publication date: Available online 11 March 2015 Source: Journal of Hydrology: Regional Studies Author(s): B.M. Hallett , H.A. Dharmagunawardhane , S. Atal , E. Valsami-Jones , S. Ahmed , W.G. Burgess Study region The Maheshwaram and Waipally catchments of Andhra Pradesh, India, and the Plonnaruwa catchment of north-central Sri Lanka. Study focus The distribution of F across eight crystalline phases and between the bedrock and the regolith at eleven sites in three catchments is documented. Mineral contributions to F release during weathering and regolith development are quantified. New hydrological insights for the region An estimate of weathering duration for the in situ regolith in Andhra Pradesh, 250–380 Ka, is close to a previous estimate for southern India. Partial or total destruction of the primary F-bearing bedrock minerals and consistent depletion of F in the remnant minerals result in a much reduced total F content in the regolith. Leaching experiments and field relationships, however, indicate a greater potential for F mobilisation to groundwater from the regolith than the bedrock. Schemes for managed aquifer recharge should beware the risk of mobilising additional F to groundwater.

Description: Publication date: March 2015 Source: Journal of Hydrology: Regional Studies, Volume 3, Supplement 1 Author(s): Salah Er-Raki

Description: Publication date: Available online 10 December 2015 Source: Journal of Hydrology: Regional Studies Author(s): Tatsuya Utsunomiya, Masaki Hata, Ryo Sugimoto, Hisami Honda, Shiho Kobayashi, Yoji Miyata, Makoto Yamada, Osamu Tominaga, Jun Shoji, Makoto Taniguchi Study focus There have been far more studies on how the variability in surface water discharge affects production of animal communities in aquatic ecosystems while less information has been accumulated on the mechanisms of how the groundwater supply works. Study region Physical and biological surveys were conducted to test the hypothesis that high level of submarine ground water discharge enhances species richness, abundance and biomass of fishes and invertebrates in coastal waters of Obama Bay, Japan, where a high contribution of nutrients (ca. 65% of phosphorus) to total provided through all freshwater has been reported. Survey for horizontal distribution of radon-222 ( 222 Rn) concentration showed high levels of submarine groundwater discharge in the west part of survey area. Fish and invertebrate communities were compared within a relatively small spatial scale (ca. 100 m) in relation to level of submarine groundwater discharge. New hydrological insights Species richness, abundance and biomass of fishes and abundance and biomass of turban snail and hermit crab were significantly higher in the area with high 222 Rn concentration. Abundance of gammarids, the most major prey item of the fishes, was 18 times higher in the area with high 222 Rn concentration. Since the turban snail, hermit crab and gammarids feed on producers (phytoplankton and benthic microalgae), submarine groundwater are concluded to increase species richness and production of fishes and invertebrates through providing nutrients and enhancing primary production.

Description: Publication date: March 2016 Source: Journal of Hydrology: Regional Studies, Volume 5 Author(s): A.C. de la Casa, G.G. Ovando Study region Changes in reference evapotranspiration (ET o ) may have important consequences for agricultural suitability in the central region of Argentina. Annual ET o variation was assessed, in terms of both territory and time, for the 7 decades between 1941 and 2010, analyzing the behavior of the 4 atmospheric variables which determine it: temperature, vapor pressure, wind speed and cloud cover. Study focus The influence of each variable on ET o was evaluated from a multiple regression model and a simple correlation analysis, using climate data from the observation network, and repeating this analysis using interpolated variables. In this grid scheme, linear relationships were determined between ET o and the different key atmospheric variables, plus precipitation (PP), and the t test was applied to establish the statistically significant sectors ( P 〈 0.1). Then, those areas with a significant trend change ( P 〈 0.1) were determined by the Mann–Kendall test. Finally, the interception of the grids was performed to establish their joint occurrence. New hydrological insights for the region Most of the region analyzed (>91%) presents a non-significant variation of ET o over time, with a mostly non-significant change of each driving variable, regarding both its relationship with ET o and its own trend of change. The beneficial change in agricultural suitability reported for this water-limited region was found to be produced almost exclusively by increasing PP. Graphical abstract

Description: Publication date: Available online 11 December 2015 Source: Journal of Hydrology: Regional Studies Author(s): Makoto Taniguchi, Naoki Masuhara, Kimberly Burnett Security measures of three resources; water, energy and food are analyzed for thirty two countries in the Asia Pacific region which are faced to Pacific Ocean, in terms of amounts of the resource, self-production, and diversity of sources of each resource. Diversity for all the three resources is also analyzed using surface water and groundwater for water sources; hydro power, geothermal power, solar, and biomass for energy; and cereals, vegetable, fruit, meat, and fish for food. We see high diversity of sources of water in the US and the Philippines, and a low diversity of sources of food in the US, Canada, and Indonesia. These security measures including water security show new hydrological insight for Asia-Pacific region.

Description: Publication date: Available online 10 December 2015 Source: Journal of Hydrology: Regional Studies Author(s): Aiko Endo, Izumi Tsurita, Kimberly Burnett, Pedcris M. Orencio Study region Asia, Europe, Oceania, North America, South America, Middle East and Africa. Study focus The purpose of this paper is to review and analyze the water, energy, and food nexus and regions of study, nexus keywords and stakeholders in order to understand the current state of nexus research. New hydrological insights Through selected 37 projects, four types of nexus research were identified including water–food, water–energy–food, water–energy, and climate related. Among them, six projects (16%) had a close linkage with water–food, 11 (30%) with water–energy–food, 12 (32%) with water–energy, and eight (22%) with climate. The regions were divided into Asia, Europe, Oceania, North America, South America, Middle East and Africa. North America and Oceania had a tendency to focus on a specific nexus type, water–energy (46%) and climate (43%), while Africa had less focus on water–energy (7%). Regarding keywords, out of 37 nexus projects, 16 projects listed keywords in their articles. There were 84 keywords in total, which were categorized by the author team depending on its relevance to water, food, energy, climate, and combination of water–food–energy–climate, and 40 out of 84 keywords were linked with water and only 4 were linked with climate. As for stakeholders, 77 out of 137 organizations were related to research and only two organizations had a role in media.

Description: Publication date: March 2016 Source: Journal of Hydrology: Regional Studies, Volume 5 Author(s): Shilpa M. Asokan, Peter Rogberg, Arvid Bring, Jerker Jarsjö, Georgia Destouni Study region The large semi-arid Aral Region in Central Asia and the smaller tropical Mahanadi River Basin (MRB) in India. Study focus Few studies have so far evaluated the performance of the latest generation of global climate models on hydrological basin scales. We here investigate the performance and projections of the global climate models in the Coupled Model Intercomparison Project, Phase 5 (CMIP5) for freshwater fluxes and their changes in two regional hydrological basins, which are both irrigated but of different scale and with different climate. New hydrological insights for the region For precipitation in both regions, model accuracy relative to observations has remained the same or decreased in successive climate model generations until and including CMIP5. No single climate model out-performs other models across all key freshwater variables in any of the investigated basins. Scale effects are not evident from global model application directly to freshwater assessment for the two basins of widely different size. Overall, model results are less accurate and more uncertain for freshwater fluxes than for temperature, and particularly so for model-implied water storage changes. Also, the monsoon-driven runoff seasonality in MRB is not accurately reproduced. Model projections agree on evapotranspiration increase in both regions until the climatic period 2070–2099. This increase is fed by precipitation increase in MRB and by runoff water (thereby decreasing runoff) in the Aral Region.

Description: Publication date: March 2016 Source: Journal of Hydrology: Regional Studies, Volume 5 Author(s): Justin A. Schulte, Raymond G. Najjar, Ming Li Study region The Mid-Atlantic region of the United States. Study focus An understanding of past streamflow variability is necessary for developing future management practices that will help mitigate the impacts of extreme events such as drought or floods on agriculture and other human activities. To better understand mechanisms driving streamflow variability at all timescales, annual to multi-decadal streamflow variability of three major rivers in the Mid-Atlantic region of the United States (the Susquehanna, Delaware, and Hudson Rivers) was studied in the context of climate modes using correlation and wavelet analyses. New hydrological insights for the region Results from the correlation analysis detected statistically significant relationships between climate indices and streamflow that were similar for the three rivers. The results from the wavelet analysis showed that 18- and 26-year periodicities were embedded in the streamflow time series. Decadal variability of streamflow was coherent with the El-Niño Southern Oscillation (SO) and the Pacific Decadal Oscillation (PDO). The time series for the PDO and SO indices and precipitation were found to be synchronized to the decadal variability of a global circulation pattern consisting of a Rossby wave train emanating from the North Pacific. The SO explained 37–54% of the 1960s drought, 33–49% of the 1970s pluvial, and 19–50% of the 2000s pluvial in the three river basins.

Description: 〈p〉Publication date: 15 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Algebra, Volume 518〈/p〉 〈p〉Author(s): William Cocke, Meng-Che “Turbo” Ho〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Word maps provide a wealth of information about finite groups. We examine the connection between the probability distribution induced by a word map and the underlying structure of a finite group. We show that a finite group is nilpotent if and only if every surjective word map has fibers of uniform size. Moreover, we show that probability distributions themselves are sufficient to identify nilpotent groups, and these same distributions can be used to determine abelian groups up to isomorphism. In addition we answer a question of Amit and Vishne.〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Algebra, Volume 518〈/p〉 〈p〉Author(s): Benjamin Steinberg〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Work of Jean Renault shows that, for topologically principal étale groupoids, a diagonal-preserving isomorphism of reduced 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si1.gif" overflow="scroll"〉〈msup〉〈mrow〉〈mi〉C〈/mi〉〈/mrow〉〈mrow〉〈mo〉⁎〈/mo〉〈/mrow〉〈/msup〉〈/math〉-algebras yields an isomorphism of groupoids. Several authors have proved analogues of this result for ample groupoid algebras over integral domains under suitable hypotheses. In this paper, we extend the known results by allowing more general coefficient rings and by weakening the hypotheses on the groupoids. Our approach has the additional feature that we only need to impose conditions on one of the two groupoids. Applications are given to Leavitt path algebras.〈/p〉〈/div〉

Description: 〈p〉Publication date: November 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Comptes Rendus Geoscience, Volume 350, Issue 7〈/p〉 〈p〉Author(s): Ilias Fountoulakis, Christos S. Zerefos, Alkiviadis F. Bais, John Kapsomenakis, Maria-Elissavet Koukouli, Nozomu Ohkawara, Vitali Fioletov, Hugo De Backer, Kaisa Lakkala, Tomi Karppinen, Ann R. Webb〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Spectral UV records of solar irradiance at stations over Europe, Canada, and Japan were used to study long-term trends at 307.5 nm for a 25-year period, from 1992 to 2016. Ground-based measurements of total ozone, as well as satellite measurements of the Aerosol Index, the Total Cloud Cover and the surface reflectivity were also used in order to attribute the estimated changes of the UV to the corresponding changes of these factors. The present study shows that over the Northern Hemisphere, the long-term changes in UV-B radiation reaching the Earth's surface vary significantly over different locations, and that the main drivers of these variations are changes in aerosols and total ozone. At high latitudes, part of the observed changes may also be attributed to changes in the surface reflectivity. Over Japan, the UV-B irradiance at 307.5 nm has increased significantly by ∼3%/decade during the past 25 years, possibly due to the corresponding significant decrease of its absorption by aerosols. It was found that the greatest part of this increase took place before the mid-2000s. The only European station, over which UV radiation increases significantly, is that of Thessaloniki, Greece. Analysis of the clear-sky irradiance for the particular station shows increasing irradiance at 307.5 nm by ∼3.5%/decade during the entire period of study, with an increasing rate of change during the last decade, possibly again due to the decreasing absorption by aerosols.〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Algebra, Volume 518〈/p〉 〈p〉Author(s): Serge Bouc, Jacques Thévenaz〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A correspondence functor is a functor from the category of finite sets and correspondences to the category of 〈em〉k〈/em〉-modules, where 〈em〉k〈/em〉 is a commutative ring. A main tool for this study is the construction of a correspondence functor associated to any finite lattice 〈em〉T〈/em〉. We prove for instance that this functor is projective if and only if the lattice 〈em〉T〈/em〉 is distributive. Moreover, it has quotients which play a crucial role in the analysis of simple functors. The special case of total orders yields some more specific and complete results.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 1 November 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Complexity〈/p〉 〈p〉Author(s): Robert J. Kunsch, Erich Novak, Daniel Rudolf〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We compute the integral of a function or the expectation of a random variable with minimal cost and use, for our new algorithm and for upper bounds of the complexity, i.i.d. samples. Under certain assumptions it is possible to select a sample size based on a variance estimation, or – more generally – based on an estimation of a (central absolute) 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si1.gif"〉〈mi〉p〈/mi〉〈/math〉-moment. That way one can guarantee a small absolute error with high probability, the problem is thus called solvable. The expected cost of the method depends on the 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si1.gif"〉〈mi〉p〈/mi〉〈/math〉-moment of the random variable, which can be arbitrarily large. In order to prove the optimality of our algorithm we also provide lower bounds. These bounds apply not only to methods based on i.i.d. samples but also to general randomized algorithms. They show that – up to constants – the cost of the algorithm is optimal in terms of accuracy, confidence level, and norm of the particular input random variable. Since the considered classes of random variables or integrands are very large, the worst case cost would be infinite. Nevertheless one can define adaptive stopping rules such that for each input the expected cost is finite. We contrast these positive results with examples of integration problems that are not solvable.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 1 November 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Algebra〈/p〉 〈p〉Author(s): Volker Gebhardt, Stephen Tawn〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉We present an improved orderly algorithm for constructing all unlabelled lattices up to a given size, that is, an algorithm that constructs the minimal element of each isomorphism class relative to some total order.〈/p〉 〈p〉Our algorithm employs a stabiliser chain approach for cutting branches of the search space that cannot contain a minimal lattice; to make this work, we grow lattices by adding a new layer at a time, as opposed to adding one new element at a time, and we use a total order that is compatible with this modified strategy.〈/p〉 〈p〉The gain in speed is between one and two orders of magnitude. As an application, we compute the number of unlabelled lattices on 20 elements.〈/p〉 〈/div〉

Description: 〈p〉Publication date: February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Journal of Combinatorics, Volume 76〈/p〉 〈p〉Author(s): Joshua Hallam, Jeremy L. Martin, Bruce E. Sagan〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Let 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si39.gif"〉〈mi〉G〈/mi〉〈/math〉 be a graph with vertex set 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si2.gif"〉〈mrow〉〈mo〉{〈/mo〉〈mn〉1〈/mn〉〈mo〉,〈/mo〉〈mo〉…〈/mo〉〈mo〉,〈/mo〉〈mi〉n〈/mi〉〈mo〉}〈/mo〉〈/mrow〉〈/math〉. A spanning forest 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si3.gif"〉〈mi〉F〈/mi〉〈/math〉 of 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si39.gif"〉〈mi〉G〈/mi〉〈/math〉 is 〈em〉increasing〈/em〉 if the sequence of labels on any path starting at the minimum vertex of a tree of 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si3.gif"〉〈mi〉F〈/mi〉〈/math〉 forms an increasing sequence. Hallam and Sagan showed that the generating function 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si6.gif"〉〈mi mathvariant="normal"〉ISF〈/mi〉〈mrow〉〈mo〉(〈/mo〉〈mi〉G〈/mi〉〈mo〉,〈/mo〉〈mi〉t〈/mi〉〈mo〉)〈/mo〉〈/mrow〉〈/math〉 for increasing spanning forests of 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si39.gif"〉〈mi〉G〈/mi〉〈/math〉 has all nonpositive integral roots. Furthermore they proved that, up to a change of sign, this polynomial equals the chromatic polynomial of 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si39.gif"〉〈mi〉G〈/mi〉〈/math〉 precisely when 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si9.gif"〉〈mn〉1〈/mn〉〈mo〉,〈/mo〉〈mo〉…〈/mo〉〈mo〉,〈/mo〉〈mi〉n〈/mi〉〈/math〉 is a perfect elimination order for 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si39.gif"〉〈mi〉G〈/mi〉〈/math〉. We give new, purely combinatorial proofs of these results which permit us to generalize them in several ways. For example, we are able to bound the coefficients of 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si6.gif"〉〈mi mathvariant="normal"〉ISF〈/mi〉〈mrow〉〈mo〉(〈/mo〉〈mi〉G〈/mi〉〈mo〉,〈/mo〉〈mi〉t〈/mi〉〈mo〉)〈/mo〉〈/mrow〉〈/math〉 using broken circuits. We are also able to extend these results to simplicial complexes using the new notion of a cage-free complex. A generalization to labeled multigraphs is also given. We observe that the definition of an increasing spanning forest can be formulated in terms of pattern avoidance, and we end by exploring spanning forests that avoid the patterns 231, 312 and 321.〈/p〉〈/div〉

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sustainable Cities and Society, Volume 44〈/p〉 〈p〉Author(s): Hye Soo Suh, Daeung Danny Kim〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The study demonstrated a systematic approach to achieve the nearly zero energy community building through the assessment of energy performance of the combined passive and active design solutions and renewable energy systems. Among 16 community buildings, four buildings were selected and the parameters that had an impact on energy consumption were identified through the analysis of electricity and gas consumption. After the validation with the measured data of electricity and gas, the energy simulation was used to model the newly constructed community building. A combined passive and active design strategy was applied to improve the energy performance. To offset the energy use for the domestic hot water, possible renewable energy systems such as the PV system, the solar thermal system, and the geothermal heat pump system were reviewed and their efficiency was analyzed. As a result, the combination of the PV system with additional PV modules and the geothermal system was chosen for the achievement of the nearly zero energy target.〈/p〉〈/div〉

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sustainable Cities and Society, Volume 44〈/p〉 〈p〉Author(s): Zhiqiang John Zhai, Jacob Michael Helman〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Climate change is a widely acknowledged major environmental problem whose impacts on building energy use however are not fully understood. Various climate models have been developed and used to project climate changes; however most of existing studies on climate change impacts only use few model outcomes, providing narrow predictions on the influences. This study analyzed a large number (i.e., 56) of models and scenarios. The obtained future climate data showed a wider range of potential changes and thus impacts on building energy. Four reference climate models were identified to cover the full range of the 56 models for three time periods and seven climate zones. The accuracy of model projections was validated using historical data. The study predicted the potential energy implications of climate changes to a campus building stock. Influences of these changes on utility and economics were analyzed. The study further explored the potential impacts of climate change to the current climate zones that directly relate to building energy consumption.〈/p〉〈/div〉

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sustainable Cities and Society, Volume 44〈/p〉 〈p〉Author(s): Jorge Navarro-Rubio, Paloma Pineda, Antonio García-Martínez〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Eco-efficiency and building optimization potential of prefabricated structures to be used in new buildings are studied, focusing on the analysis of a novel dry precast beam-column connection under different durability and re-using scenarios. The analyses include structural response (via numerical models), optimization potential (material take off, building schedule and economic cost) and environmental impact (via Life Cycle Assessment, LCA). The connection is applied to a case study which is representative of common buildings: a seven-story concrete structure with frames and deck slabs. The structural response of the connection accomplishes the Eurocode safety prescriptions. Man-hours and task duration decrease around 80%, and the global schedule undergoes 60% diminution. Focusing on economic issues, when the prefabricated structural elements are reused the accumulated economic cost significantly decreases. LCA shows that durability, in terms of service life, is directly related to the environmental impact. However, other design options, such us re-using, have less repercussion in the impact categories (i.e. Global Warming Potential and Embodied Energy), and in the global cost. Results from this research could contribute to the implementation of prefabricated elements in the building stock promoting eco-efficiency.〈/p〉〈/div〉

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Technological Forecasting and Social Change, Volume 138〈/p〉 〈p〉Author(s): Jae-Woong Min, Nicholas S. Vonortas, YoungJun Kim〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This study explores the factors that contribute to the commercialization of technologies transferred from universities and public research institutes (U&PRIs) to companies. We take a step further than the established literature focusing on technology transfer to examine factors that also affect the chances of the successful commercialization of the transferred technologies through an empirical analysis of 669 technology transfer cases in Korea. The study shows that the intensity of market competition is a key factor in moderating the effects of partnership and absorptive capacity on the successful commercialization of transferred technologies. While collaboration with U&PRIs exerts a positive effect on commercialization success, this effect is weakened by the intensity of market competition. The intensity of market competition boosts the importance of company absorptive capacity for the commercialization success of the transferred technology. We conclude that strategic management of the absorptive capacities of companies and their partnership with U&PRIs are necessary ingredients of the success of technology transfer in concordance with the intensity of competition that the company faces in the market.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 31 October 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 European Journal of Operational Research〈/p〉 〈p〉Author(s): Alexandre M. Florio, Richard F. Hartl, Stefan Minner〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We present a model for the single-vehicle routing problem with stochastic demands (SVRPSD) with optimal restocking. The model is derived from a characterization of the SVRPSD as a Markov decision process (MDP) controlled by a certain class of policies, and is valid for general discrete demand probability distributions. We transform this MDP into an equivalent mixed-integer linear model, which is then used to solve small instances to optimality. By doing so, we are able to quantify the drawbacks associated with the detour-to-depot restocking policy, an assumption of many exact approaches for the (multivehicle) VRPSD. We also examine the tradeoff between the deterministic a priori cost and the stochastic restocking cost for varying route load scenarios. Finally, a wait-and-see model for the SVRPSD is proposed, and is used within a parallel heuristic to solve larger literature instances with up to 150 nodes and Poisson distributed demands. Computational experiments demonstrate the effectiveness of the heuristic approach, and also indicate under which circumstances near-optimal solutions can be obtained by the myopic strategy of a priori route cost minimization.〈/p〉〈/div〉

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Marine Policy, Volume 99〈/p〉 〈p〉Author(s): Pablo Quero García, Javier García Sanabria, Juan Adolfo Chica Ruiz〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In recent years the European Union has firmly committed itself to energy from oceans as a means of decarbonising the European energy system. Despite a favourable political landscape, the development of offshore renewables still faces economic and technological barriers, which are coupled with the inherent difficulties of an increasingly industrialised marine environment, such as complex evolving regulation, lack of knowledge regarding the possible environmental impact of such an activity, as well as spatial conflicts with other traditional and emerging uses. Most of the coastal Member States have adopted Maritime Spatial Planning (MSP) as a fundamental tool for integrated and sustainable management of human activities in the marine environment. MSP is capable of definitively driving the use of offshore renewable facilities. Its proper application supports decision making, simplifies and accelerates the process of obtaining permits, improves compatibility of uses, integrates stakeholders in planning, prevents environmental deterioration of sensitive areas, enhances the availability of information and promotes cross-border co-operation. This paper aims to evaluate the influence of maritime spatial planning processes on the advance of blue energy within the framework of the European Union. The results show positive relationships between MSP and the development of offshore renewable energy in countries such as Germany, the Netherlands and the United Kingdom.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0308597X1830304X-fx1.jpg" width="477" alt="fx1" title="fx1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Ocean & Coastal Management, Volume 167〈/p〉 〈p〉Author(s): Uxío Labarta, M〈sup〉a〈/sup〉 José Fernández-Reiriz〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉The mussels industry with a production that accounts for more than twenty five percent of the fresh product landings from the sea, and the full-time employment of more than 8000 people, is by far the largest productive activity of the Galician sea.〈/p〉 〈p〉In the 1980s was noticed an increase in productivity related to processes of innovation in the industry of mussel. Together with it, the first organizational forms of the Galician-based production sector was constituted, with a spatial and administrative reordering for mussel rafts and crops. A new reality of the sector was maintained in both the marketing guidelines and the fact of initiating a vertical integration between the mussel industry and the commercialization. Everything was accompanied by changes in markets and strong tensions: derived from red tides that limit the operating cycle and even its profitability and also from the conflicts between the producing and transforming organizations, added to the competition in the markets of other countries, mainly Chile.〈/p〉 〈p〉The reality of mussel culture and markets leads to a reformulation in the industry, with strategies for territorial diversification of suppliers, new technological improvements in production and even organizational, economic, and bioecological innovations.〈/p〉 〈/div〉 〈/div〉

Description: 〈p〉Publication date: 16 April 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Journal of Operational Research, Volume 274, Issue 2〈/p〉 〈p〉Author(s): Damiano Brigo, Marco Francischello, Andrea Pallavicini〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉Since the 2008 global financial crisis, the banking industry has been using valuation adjustments to account for default risk and funding costs. These adjustments are computed separately and added together by practitioners as if the valuation equations were linear. This assumption is too strong and does not allow to model market features such as different borrowing and lending rates and replacement default closeout. Hence we argue that the full valuation equations are nonlinear, and this paper is devoted to studying the nonlinear valuation equations introduced in Pallavicini et al (2011).〈/p〉 〈p〉We illustrate all the cash flows exchanged by the parties involved in a derivative contract, in presence of default risk, collateralisation with re-hypothecation and funding costs. Then we show how to obtain semi-linear PDEs or Forward Backward Stochastic Differential Equations (FBSDEs) from present-valuing said cash flows in an arbitrage-free setup, and we study the well-posedness of these PDEs and FBSDEs in a viscosity and classical sense.〈/p〉 〈p〉Moreover, from a financial perspective, we discuss cases where classical valuation adjustments (XVA) can be disentangled. We show how funding costs are offset by treasury valuation adjustments when one takes a whole-bank perspective in the valuation, while the same costs are not offset by such adjustments when taking a shareholder perspective. We show that although we use a risk-neutral valuation framework based on a locally risk-free bank account, our final valuation equations do not depend on the risk-free rate. Finally, we show how to consistently derive a netting set valuation from a portfolio level one.〈/p〉 〈/div〉

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Marine Policy, Volume 99〈/p〉 〈p〉Author(s): Bong-Tae Kim, Christopher L. Brown, Do-Hoon Kim〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We assess the vulnerability to climate change of Korean aquaculture based on predicted changes in seawater temperature and salinity in adjacent sea areas of the Korean Peninsula according to representative concentration pathways (RCP) scenarios. Unlike previous studies that have been conducted mostly on a national scale, we classify 14 farming species in major production regions of the Republic of Korea, and assess their vulnerability for each region, using the indicator-based method and the Intergovernmental Panel on Climate Change's definition of vulnerability in order to overcome limitations in developing specific adaptation strategies within a country. First, for each exposure, sensitivity, and adaptive capacity, specific and proper indicators are selected. Subsequently, these indicators are estimated and weighted to analyze vulnerability to climate change. The results show that the absolute level of vulnerability is high in a long-term period of RCP8.5 in which exposure becomes severe, whereas the relative vulnerability is similar among farming species and regions. Specifically, vulnerability is at the highest level in seaweed, such as laver and sea mustard, while fish, shrimp, and abalone are relatively less vulnerable to climate change.〈/p〉〈/div〉

Description: 〈p〉Publication date: December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Transport Geography, Volume 73〈/p〉 〈p〉Author(s): Chengxi Liu, Yusak O. Susilo, Dimas B.E. Dharmowijoyo〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The activity space of an individual is defined as the activity-travel environment which a traveller is using for his or her activities (Axhausen et al., 2002). It is limited by this individual's ability and resources, such as available time for travel as well as his or her anchor points. However, most existing studies have focused on single individual activity space, ignoring the fact that individuals' activities often interact with that of his or her family members'. In this paper a multivariate model is proposed where the correlation between travel time of fathers and mothers, and the correlation between the activity space and travel time are modelled explicitly. The estimated correlations from these joint distributions provide insights into both the intra-household interactions in daily travel and the intrinsic relationships of the hidden limits in the dimensions of space and time. The travel time limits are modelled using a stochastic frontier model component, which can estimate an unobserved upper or lower limit for travel time expenditure. This limit usually refers to the maximum travel time budget or minimum travel time need, which denotes the maximum or minimum amount of travel time that an individual is willing or able to allocate per day. The concept of the confidence ellipse is used as a measure of activity space constructed from the multi-day travel diary data. It is hypothesised that the unobserved travel time limits and activity space sizes of fathers and mothers are correlated with each other, due to a similar spatial knowledge and accessibility to various facilities. The daily variations in the travel time expenditure of parents are also assumed to be correlated because of daily household task allocation and joint household travel. Data collected from a three-week household travel diary in the Bandung Metropolitan Area in Indonesia are used for estimation in this study. The estimated frontier model component shows that neither parent has reached their maximum travel time budget and/or minimum travel time need that they inherently must spend. Compared with other attributes, the perceived accessibility attributes play the most important role in influencing the activity space limits. For households with fully employed fathers, a trade-off mechanism is found in travel time expenditure between parents, which is likely due to the redistribution of household tasks. On the other hand, for households with fathers who are not fully employed, a complementary effect is found, arising from the joint travel among household members. The travel time budget and activity space limits of fathers are positively correlated with those of mothers. These findings call for the formulation of transport policies that consider the household as a unit, especially in developing countries such as Indonesia, to fulfil the mobility needs of different market segments, e.g., households with fully employed fathers and those with fathers who are not fully employed.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Remote Sensing of Environment, Volume 220〈/p〉 〈p〉Author(s): Xiyu Chen, Lin Liu, Annett Bartsch〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Microwave remote sensing, both active or passive, can provide useful information about the freeze/thaw (F/T) state of soil near the surface. Here we apply an edge detection algorithm on time series of indicators derived from measurements of SMAP L-band radiometer and ASCAT C-band scatterometer to detect the freeze/thaw onsets of surface soil. Comparing these results against the onsets derived from in situ measurements in Alaska, we demonstrate that this algorithm is an effective approach to detect onsets of the soil F/T transition. More specifically, our results show that the thawing onsets estimated from the SMAP data occurred 5 to 13 days earlier than the onsets estimated from the in situ measurements, which is likely due to the influence of snowmelt on the radiometer signal. The thawing onsets estimated from the ASCAT data were about 6 days later than the in situ onsets. Our estimated freezing onsets from each microwave remote sensing dataset were close to the in situ onsets (1–5 days). We also compare our estimated onsets with those from the SMAP Level 3 F/T product and the mean biases for thawing and freezing onsets are 1 ± 2 and 1 ± 3 days, respectively. Furthermore, we illustrate the complementary nature of the SMAP and ASCAT measurements and the potential for combining these two to differentiate snowmelt from soil thawing events.〈/p〉〈/div〉

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Remote Sensing of Environment, Volume 220〈/p〉 〈p〉Author(s): Mathilde Cancet, David Griffin, Madeleine Cahill, Bertrand Chapron, Johnny Johannessen, Craig Donlon〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉Australia's marginal seas include a wide range of ocean current regimes ranging from tide-dominated in the North-West where the continental shelf is wide, to boundary current- and eddy-dominated in the South-East, where the shelf is narrow. Here, we take the opportunity to test the GlobCurrent surface ocean current products against in-situ observations in these two contrasting regimes. Observations by Acoustic Doppler Current Profiler (ADCP) instruments of Australia's Integrated Marine Observing System (IMOS) and drifting buoys of the Global Drifting Programme (GDP) are used.〈/p〉 〈p〉The monthly-timescale variability of the GlobCurrent alongshore current component is in moderately good agreement with the observations on the continental shelf in the South-East but neither the shorter period variability nor the long-term mean are representative of the ADCP observations. While the observed tidal currents are negligibly small, the wind-driven signals are not. But these are evidently too transient to be adequately sampled by altimetry. The inclusion of an Ekman component does not represent these signals because the interaction of the Ekman transport with the coastal boundary condition is not included. Similarly, the error of the time-mean velocity, which is the dominant error, is because that product is not designed to represent the highly anisotropic nature of the sea level gradients over the continental shelf nor the constraints on the flow field that are imposed by the topography. We thus conclude that the GlobCurrent product needs improvements before it can be described as very suitable for applications on this, and probably other, narrow continental shelf. Off the continental shelf, in contrast, the GlobCurrent products compare quite well with the trajectories of drifting buoys, confirming that the products are quite suitable for blue-water applications.〈/p〉 〈p〉In contrast to the South-East, the tides are very strong in the North-West region of Australia. The sub-tidal variability is weak, in both relative and absolute senses. Consequently, the removal of the tidal signal from the sea level observations needs to be very complete for the residual error to be smaller than the true sub-tidal signal. Transient wind forced signals are also occasionally large so this step of the de-aliasing also needs to be very accurate. Unfortunately, it appears that more work is required before accurate estimates of sub-tidal variability are available from GlobCurrent: the magnitude of the GlobCurrent estimates of sub-tidal current variability far exceed the magnitude of, and are uncorrelated with, the detided ADCP data.〈/p〉 〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 1 November 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Fuzzy Sets and Systems〈/p〉 〈p〉Author(s): Michal Holčapek〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this article, we propose an axiomatic system for fuzzy “cardinality” measures (referred to as fuzzy c-measures for short) assigning to each finite fuzzy set a generalized cardinal that expresses the number of elements that the fuzzy set contains. The system generalizes an axiomatic system introduced by J. Casasnovas and J. Torrens (2003). We show that each fuzzy c-measure is determined by two appropriate homomorphisms between the reducts of residuated-dually residuated (rdr-)lattices. For linearly ordered rdr-lattices, we prove that each fuzzy c-measure is a product of a non-decreasing and a non-increasing fuzzy c-measure, which indicates that there is a close relation between fuzzy c-measures and FGCount, FLCount and FECount provided by L.A. Zadeh (1983) and generalized by M. Wygralak (2001). Finally, the relationship of fuzzy c-measures to graded equipollence introduced in the first part of this contribution is analyzed.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 30 October 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Technological Forecasting and Social Change〈/p〉 〈p〉Author(s): Sonal Choudhary, Rakesh Nayak, Sushma Kumari, Homagni Choudhury〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Drawing on theories of acculturation and information diffusion, this paper examines whether social media usage, intergroup contacts and information dissemination influence the cultural adaptation of three ethnic groups, and its implications on sustainable consumption behaviour. Twenty-four semi-structured interviews containing multiple dimensions of social media uses, acculturation, food consumption behaviour, and information diffusion were administered to a sample of Indians (living in the home country), British Indians (living in the host country for more than 10 years) and White British (natives of Britain) users of social media. Our findings suggest that there is a clear link between the integrated strategy of acculturation and information diffusion on social media, which influences acculturation to sustainable food consumption behaviour among social media users. Managerial implications of this research finding are that intervention in information diffusion aids acculturation through the social media, which serves to infuse social media and sustainability strategist with knowledge to best influence the consumers in developing sustainable food consumption behaviour. This research also identifies opportunities to expand this academic research and contribute further to the theories of remote acculturation on which limited research has been done.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology, Volume 568〈/p〉 〈p〉Author(s): E.A. Zakharova, I.N. Krylenko, A.V. Kouraev〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Due to the rapid decline of 〈em〉in situ〈/em〉 observations on river discharge in Arctic regions, evaluation of the continental freshwater input to the Arctic Ocean has become problematic and necessitates the development of alternative approaches based on remote sensing. Radar altimetric satellites have demonstrated high potential for estimation of river water discharge. Compared to polar orbiting altimeters, non-polar orbit satellites have an advantage in temporal sampling. Their greatest drawback, however, is spatial coverage: observations do not cover the low reaches of most parts of Arctic rivers. In this study of the Lena River, we demonstrate a way to overcome this limitation by using a combination of 〈em〉in situ〈/em〉 observations from tributaries and satellite observations in the middle river reaches. The water discharge as well as monthly and annual water flow were evaluated using three virtual stations. Direct combination of the water level from these virtual stations was not possible because of the difference in seasonal amplitude. However, the combination of altimetric discharge from the three independently processed tracks significantly improves the flow retrievals. The accuracy of the monthly water flow estimates at the river outlet is 23%. It increases with the integration time giving 7% for annual flow.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology, Volume 568〈/p〉 〈p〉Author(s): Weihua Wu, Mingzhao Sun, Xiang Ji, Shuyi Qu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉To determine the influence of the Mesozoic Yanshanian orogeny in East Asia on contemporaneous Sr isotopic evolution of seawater, we systematically investigated the weathering profile, riverbed sediment and stream water in mono-lithological small granitic watersheds of the Jiuhua Mountains, Anhui, eastern China. Analysis based on 190 samples from 1 to 2 samplings per month during an entire hydrological year, spanning July 2014 to June 2015, shows that the intra-annual change of Sr concentration is 10–70%, but 〈sup〉87〈/sup〉Sr/〈sup〉86〈/sup〉Sr ratios only exhibit a slight change (0.709148–0.710427). This result indicates that using single sampling data to evaluate the influence of chemical weathering on the 〈sup〉87〈/sup〉Sr/〈sup〉86〈/sup〉Sr ratio evolution of seawater may cause some deviations. The 〈sup〉87〈/sup〉Sr/〈sup〉86〈/sup〉Sr ratio in the small granitic watersheds of the Jiuhua Mountains is 0.709148–0.710427 with an average of 0.710021, which is significantly higher than the lowest value (0.7068, ∼160 Ma) of seawater in the Phanerozoic. During and after this period, the East Asian continent experienced a strong tectonic event — Yanshanian orogeny and formed widespread Jurassic–Cretaceous igneous rocks, such as the Jiuhua Mountains granite in the Yangtze Block. The Yanshanian granites in several main tectonic units in China exhibit high radiogenic Sr characteristics. Combined with the evidence of enhanced chemical weathering during Late Jurassic-Early Cretaceous, the notable increase of the seawater 〈sup〉87〈/sup〉Sr/〈sup〉86〈/sup〉Sr ratio after 160 Ma may be related to the Yanshanian orogeny in East Asia.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0022169418308412-ga1.jpg" width="245" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Geoforum, Volume 97〈/p〉 〈p〉Author(s): Rebecca Sandover, Samuel Kinsley, Stephen Hinchliffe〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Geographers and other social scientists have for some time been interested in how scientific and environmental controversies emerge and become public or collective issues. Social media are now key platforms through which these issues are publically raised and through which groups or publics can organise themselves. As media that generate data and traces of networking activity, these platforms also provide an opportunity for scholars to study the character and constitution of those groupings. In this paper we lay out a method for studying these ‘issue publics’: emergent groupings involved in publicising an issue. We focus on the controversy surrounding the state-sanctioned cull of wild badgers in England as a contested means of disease management in cattle. We analyse two overlapping groupings to demonstrate how online issue publics function in a variety of ways – from the ‘echo chambers’ of online sharing of information, to the marshalling of agreements on strategies for action, to more dialogic patterns of debate. We demonstrate the ways in which digital media platforms are themselves performative in the formation of issue publics and that, while this creates issues, we should not retreat into debates around the ‘proper object’ of research but rather engage with the productive complications of mapping social media data into knowledge (Whatmore, 2009). In turn, we argue that online issue publics are not homogeneous and that the lines of heterogeneity are neither simple or to be expected and merit study as a means to understand the suite of processes and novel contexts involved in the emergence of a public.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sustainable Cities and Society, Volume 44〈/p〉 〈p〉Author(s): Fabiana Silvero, Fernanda Rodrigues, Sergio Montelpare, Enrico Spacone, Humberto Varum〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Nowadays, energy efficiency (EE) is presented as a reliable strategy towards sustainable development, but its application has not been developed equitably worldwide, since most EE policies have been implemented in industrialised nations, and developing countries are still in the process of improving their EE levels. This paper provides a contextual framework to analyse the EE situation in countries of Latin American Southern Cone, such as Argentina, Brazil, Chile and Uruguay, with the objective of describing the policies and projects implemented, highlighting the results achieved and outlining the path followed towards EE. A focus was placed on the building sector, where thermal performance standards and the programs to achieve EE in this sector were briefly described. Furthermore, a comparison between these standards was developed, to identify the country with the most demanding standard. As a result, it was found that all the countries are implementing several EE programs and recognising the importance of this issue within their policies. Through this paper, energy policy implications of the region can be identified, which can be useful for energy policymakers of other countries, who are beginning to consider EE policies and can take as an example the path followed by the countries analysed.〈/p〉〈/div〉

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Transportation Research Part F: Traffic Psychology and Behaviour, Volume 60〈/p〉 〈p〉Author(s): Jennifer Howcroft, Frank Knoefel, Bruce Wallace, Rafik Goubran, Michelle M. Porter, Shawn Marshall〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Naturalistic in-car driving informatics provides opportunities to identify links between driving behaviours and cognitive and physical health status. The coefficient of variation was used to evaluate deceleration event variability (1) for differences between 171 older adult drivers grouped based on physical and cognitive scores and (2) for changes that aligned with longitudinal health changes in 62 older adult drivers. Differences in older adult physical and cognitive health status were related to deceleration event variability. Greater deceleration event variability was identified in individuals with better cognitive health, with two exceptions. There were also deceleration events subsets where individuals with poorer physical health status exhibited greater variability in deceleration patterns than those with better health status. CoV-measured deceleration event variability did significantly decrease for individuals with longitudinal cognitive health decline and for individuals with longitudinal physical health declines (velocity signal only) for decelerations subsets and CoV increased for individuals with longitudinal physical health decline for acceleration and jerk signals for event deceleration subsets. These findings suggest that worse cognitive health may limit older adult driver’s ability to adapt deceleration patterns when needed, resulting in lower CoV-measured variability. However, particularly in situations that require less adaptation to deceleration patterns, worse physical health may induce unnecessary variability during deceleration events. Further investigation is warranted to determine whether differences in variability relate to successful braking collision avoidance behaviours.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Mathematical Analysis and Applications, Volume 471, Issues 1–2〈/p〉 〈p〉Author(s): Rasmus Bentmann〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We show that a 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si1.gif" overflow="scroll"〉〈msup〉〈mrow〉〈mi mathvariant="normal"〉C〈/mi〉〈/mrow〉〈mrow〉〈mo〉⁎〈/mo〉〈/mrow〉〈/msup〉〈/math〉-algebra “looking like” a Cuntz–Krieger algebra is a Cuntz–Krieger algebra. This implies that, in an appropriate sense, the class of Cuntz–Krieger algebras is closed under extensions of real rank zero.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 1 November 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of the Franklin Institute〈/p〉 〈p〉Author(s): Yang Wang, Jing Yao, Guanrong Chen〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉An evolving super-network model with inter-vehicle communications (IVC) is established in this paper, which consists of two layers: the traffic network and the communication network. The model incorporates key parameters of wireless communication devices (characterized by their transmission ranges and bandwidths), market penetration rate and vehicle distribution. The impacts of these parameters on the topological structure of the model are revealed and verified via simulations using a modified car-following model with inter-vehicle communications. Finally, some guidelines are presented for adapting the topological organization of the communication network to the environment by tuning the key parameters.〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Mathematical Analysis and Applications, Volume 470, Issue 2〈/p〉 〈p〉Author(s): 〈/p〉

Description: 〈p〉Publication date: 15 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Algebra, Volume 518〈/p〉 〈p〉Author(s): Grzegorz Bobiński, Jan Schröer〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We call a finite-dimensional 〈em〉K〈/em〉-algebra 〈em〉A geometrically irreducible〈/em〉 if, for all 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si1.gif" overflow="scroll"〉〈mi〉d〈/mi〉〈mo〉≥〈/mo〉〈mn〉0〈/mn〉〈/math〉, all connected components of the affine scheme of 〈em〉d〈/em〉-dimensional 〈em〉A〈/em〉-modules are irreducible. We prove that a geometrically irreducible algebra with exactly two simple modules has to be of a very special form, which we describe. Based on this result we prove that every minimal geometrically irreducible algebra without shortcuts in its Gabriel quiver has at most two simple modules.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 30 October 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Fuzzy Sets and Systems〈/p〉 〈p〉Author(s): Dragan Jočić, Paweł Drygaś, Ivana Štajner-Papuga〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The issue of distributivity is crucial for many different theoretical areas such as the utility theory and the integration theory. Also, this problem is of high interest for modelling some practical situations from, e.g., fields of economics and social sciences. Thus, recently, the distributivity equations have been studied for different classes of aggregation operators by a significant number of researchers. The focus of this paper in particular is on solving the left and the right distributivity equations between semi-t-operators.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 30 October 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Fuzzy Sets and Systems〈/p〉 〈p〉Author(s): Andrey G. Bronevich, Igor N. Rozenberg〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉It is an important feature of a monotone measure that it is not additive in general. In the paper we propose the mathematical tool, based on canonical sequences of monotone measures, for analyzing additivity of monotone measures on subalgebras and give a way of generating such monotone measures. It turns out that the generating rule can be considered as an effect of a linear operator defined on the set of monotone measures. We also investigate in what cases the sequence of such operators behaves commutatively and preserve continuity properties from the generating monotone measure.〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Estuarine, Coastal and Shelf Science, Volume 217〈/p〉 〈p〉Author(s): Chao Chen, Jiaoqi Fu, Shuai Zhang, Xin Zhao〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉As a dynamic belt between land and oceans, coastline provides rich information on land-ocean interactions. Sensitive to climate and anthropogenic influences, the changing coastline affects intertidal mudflat resources and the coastal environment. In this study, the greenness and wetness components of the tasseled cap transformation (TCT) were used to extract coastline information. Due to the high total suspended sediment content that leads to the failure of traditional method, sea-waterbody information extraction was initially carried out by TCT. After considering the characteristics of coastline in remote sensing images and coastline morphology in the natural world, the coastline with shorter length was eliminated and the intermittent coastline was connected based on the coordinate geometry description (such as length, distance, and direction). Finally, the results of the coastline information extraction were superimposed on the original images to evaluate accuracy. The experimental results indicated that the proposed method was more effective in clearly delineating the land-ocean boundary. The producer's accuracy and user's accuracy were 0.95 and 0.91, respectively, and the length extraction error was −2.16%. Therefore, the proposed method was more successful for coastline information extraction in the area with high sediment concentration.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 30 October 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Fuzzy Sets and Systems〈/p〉 〈p〉Author(s): Ľubomíra Horanská, Peter Sarkoci〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This paper answers the problem of copulas invariant with respect to 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si1.gif" overflow="scroll"〉〈mo stretchy="false"〉(〈/mo〉〈mi〉a〈/mi〉〈mo〉,〈/mo〉〈mi〉b〈/mi〉〈mo stretchy="false"〉)〈/mo〉〈/math〉-transformations recently proposed by Horanská and Kolesárová (2017) [8]. Using tools from ergodic theory and iterated function systems we prove that the conjecture formulated therein is not true in general and for every 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si127.gif" overflow="scroll"〉〈mo stretchy="false"〉(〈/mo〉〈mi〉a〈/mi〉〈mo〉,〈/mo〉〈mi〉b〈/mi〉〈mo stretchy="false"〉)〈/mo〉〈mo〉∈〈/mo〉〈msup〉〈mrow〉〈mo stretchy="true"〉]〈/mo〉〈mn〉0〈/mn〉〈mo〉,〈/mo〉〈mn〉1〈/mn〉〈mo stretchy="true"〉[〈/mo〉〈/mrow〉〈mrow〉〈mn〉2〈/mn〉〈/mrow〉〈/msup〉〈/math〉 we construct a one-parametric class of nontrivial copulas invariant with respect to 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si1.gif" overflow="scroll"〉〈mo stretchy="false"〉(〈/mo〉〈mi〉a〈/mi〉〈mo〉,〈/mo〉〈mi〉b〈/mi〉〈mo stretchy="false"〉)〈/mo〉〈/math〉-transformation.〈/p〉〈/div〉

Description: 〈p〉Publication date: December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Transportation Research Part D: Transport and Environment, Volume 65〈/p〉 〈p〉Author(s): Michel André, Anaïs Pasquier, Marion Carteret〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Low emission zones are frequently envisaged as a means of decreasing air pollution in city centres. In the present study, we used video monitoring to characterize the in-use local vehicle fleet at several points in the Île-de-France region (which includes the city of Paris), enabling accurate description of the type of engine and vehicle age and emission standard, which together determine their pollutant emission levels. Local vehicle fleets differed from French national estimates, as further confirmed by a Regional Mobility Survey. Both approaches (video monitoring and mobility survey) demonstrated geographical differences in the proportions of diesel and of recent vehicles. Economically advantaged areas, with lower rates of polluting and diesel-fuelled vehicles, are thus further advantaged as regards air quality and less affected by driving restrictions. Simulation of pollutant emissions demonstrated the sensitivity of the estimates to local fleet composition. They also raised the important contributions of traffic outside the city centre, of heavy vehicles and cold starts. Knowledge of the local vehicle fleet is thus important for designing low emission zones that will be effective in terms of air pollution and equitable in terms of geographical areas.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Transportation Research Part C: Emerging Technologies, Volume 97〈/p〉 〈p〉Author(s): Alexandros Angelopoulos, Damianos Gavalas, Charalampos Konstantopoulos, Damianos Kypriadis, Grammati Pantziou〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The asymmetric demand-offer problem represents a major challenge for one-way vehicle sharing systems (VSS) affecting their economic viability as it necessitates the engagement of considerable human (and financial) resources in relocating vehicles to satisfy customer demand. In this paper, we propose a novel approach which involves user-based vehicle relocations to address supply-and-demand mismatches; in our approach, VSS users are offered price incentives so as to accept picking up their vehicle from an oversupplied station and/or to drop it off to an under-supplied station. The system incentivizes users based on the priorities of vehicle relocations among stations, taking into account the fluctuating demand for vehicles and parking places at different stations over time. A graph-theoretic approach is employed for modeling the problem of allocating vehicles to users in a way that maximizes the profit of the system taking into account the budget the VSS can afford to spend for rewarding users, as well as the users’ strategic behavior. We present two different schemes for incentivizing users to act in favour of the system. Both schemes consider budget constraints and are truthful and budget-feasible. We have extensively evaluated our approach through simulations which demonstrated significant gain with respect to the number of completed trips and system revenue. We have also validated our approach through pilot trials conducted in a free-floating e-motorbike sharing system in the framework of an EU-funded research project.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Transportation Research Part F: Traffic Psychology and Behaviour, Volume 60〈/p〉 〈p〉Author(s): Jing Shi, Meiyu Liu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Inappropriate lane changing behaviour increases a driver’s risk of being involved in a crash and the injury severity levels. It is hypothesized in this study that differentiated per-lane speed limit freeways could reduce inappropriate lane changing behaviours. A driving simulator experiment was conducted to investigate drivers’ lane changing behaviour and the corresponding workload levels when different speed limit values are assigned to different lanes. Participants (〈em〉N〈/em〉 = 36) experienced three different test scenarios with different speed limit configurations. Lane changing behaviours are compared in regards to five measures describing lane changing behaviour. Meanwhile, task workload indexes were developed to evaluate key aspects of drivers’ subjective experience of the test. The results reveal that the speed limit configurations have a considerable impact on lane changing behaviour as well as on the corresponding driving workload levels. This applies especially to the scenario with both different maximum and minimum speed limits for adjacent lanes, with drivers behaving differently than they did in other situations. Lane changes were found to be less frequent and have shorter durations, and drivers tended to avoid the dangerous behaviour of “rolling on the lane edge”, therefore these compensatory safety-prone driving strategies suggest an enhanced driving safety level in association with the differentiated per-lane speed limit scenarios. The findings could provide important references for traffic management of freeways.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Transportation Research Part B: Methodological, Volume 118〈/p〉 〈p〉Author(s): Qian-Wen Guo, Shumin Chen, Paul Schonfeld, Zhongfei Li〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We address optimal rail transit investment issues considering time-inconsistent preferences and population uncertainty. Instead of adopting the typical real options approach which assumes that authorities possess a constant discount rate over time, we propose an extension of real options analysis by modeling authorities’ intertemporal choices with a quasi-hyperbolic discount function. Depending on the assumption about the strategies guiding the behaviors of future authorities, we consider three types of authorities, namely time-consistent authority, naïve authority and sophisticated authority, of which the latter two are time-inconsistent. First, an optimal transit investment timing model is proposed. Then, solutions for the above three types of authorities are derived and compared. We demonstrate the performance of the proposed model by conducting numerical tests and applying it to Dalian, China. Main findings include: (1) an authority with time-inconsistent preferences makes decisions earlier than a standard, time-consistent authority; (2) the sophisticated authority invests earlier than the naïve authority. Other implications of considering time-inconsistent preferences are also identified.〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Topology and its Applications, Volume 251〈/p〉 〈p〉Author(s): Javier Camargo, David Maya, Luis Ortiz〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A 〈em〉continuum〈/em〉 is a compact connected metric space. A non-empty closed subset 〈em〉B〈/em〉 of a continuum 〈em〉X does not block〈/em〉〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si2.gif" overflow="scroll"〉〈mi〉x〈/mi〉〈mo〉∈〈/mo〉〈mi〉X〈/mi〉〈mo〉∖〈/mo〉〈mi〉B〈/mi〉〈/math〉 provided that the union of all subcontinua of 〈em〉X〈/em〉 containing 〈em〉x〈/em〉 and contained in 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si3.gif" overflow="scroll"〉〈mi〉X〈/mi〉〈mo〉∖〈/mo〉〈mi〉B〈/mi〉〈/math〉 is dense in 〈em〉X〈/em〉. We denote the collection of all non-empty closed subset 〈em〉B〈/em〉 of 〈em〉X〈/em〉 such that 〈em〉B〈/em〉 does not block each element of 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si3.gif" overflow="scroll"〉〈mi〉X〈/mi〉〈mo〉∖〈/mo〉〈mi〉B〈/mi〉〈/math〉 by 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si4.gif" overflow="scroll"〉〈mrow〉〈mi mathvariant="script"〉NB〈/mi〉〈/mrow〉〈mo stretchy="false"〉(〈/mo〉〈msub〉〈mrow〉〈mi mathvariant="script"〉F〈/mi〉〈/mrow〉〈mrow〉〈mn〉1〈/mn〉〈/mrow〉〈/msub〉〈mo stretchy="false"〉(〈/mo〉〈mi〉X〈/mi〉〈mo stretchy="false"〉)〈/mo〉〈mo stretchy="false"〉)〈/mo〉〈/math〉. In this paper we show some properties of the hyperspace 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si4.gif" overflow="scroll"〉〈mrow〉〈mi mathvariant="script"〉NB〈/mi〉〈/mrow〉〈mo stretchy="false"〉(〈/mo〉〈msub〉〈mrow〉〈mi mathvariant="script"〉F〈/mi〉〈/mrow〉〈mrow〉〈mn〉1〈/mn〉〈/mrow〉〈/msub〉〈mo stretchy="false"〉(〈/mo〉〈mi〉X〈/mi〉〈mo stretchy="false"〉)〈/mo〉〈mo stretchy="false"〉)〈/mo〉〈/math〉. Particularly, we prove that the simple closed curve is the unique continuum 〈em〉X〈/em〉 such that 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si13.gif" overflow="scroll"〉〈mrow〉〈mi mathvariant="script"〉NB〈/mi〉〈/mrow〉〈mo stretchy="false"〉(〈/mo〉〈msub〉〈mrow〉〈mi mathvariant="script"〉F〈/mi〉〈/mrow〉〈mrow〉〈mn〉1〈/mn〉〈/mrow〉〈/msub〉〈mo stretchy="false"〉(〈/mo〉〈mi〉X〈/mi〉〈mo stretchy="false"〉)〈/mo〉〈mo stretchy="false"〉)〈/mo〉〈mo〉=〈/mo〉〈msub〉〈mrow〉〈mi mathvariant="script"〉F〈/mi〉〈/mrow〉〈mrow〉〈mn〉1〈/mn〉〈/mrow〉〈/msub〉〈mo stretchy="false"〉(〈/mo〉〈mi〉X〈/mi〉〈mo stretchy="false"〉)〈/mo〉〈/math〉, given a positive answer to a question posed by Escobedo, Estrada-Obregón and Villanueva in 2012.〈/p〉〈/div〉

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of the Franklin Institute, Volume 356, Issue 1〈/p〉 〈p〉Author(s): Gang Wang, Mohammed Chadli, Haihong Chen, Zhijin Zhou〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This paper presents a novel event-triggered 〈em〉H〈/em〉〈sub〉∞〈/sub〉 static output-feedback control for active vehicle suspension systems with network-induced delays. The proposed control schema introduces an event-triggering mechanism in the suspension system such that the communication resources can be significantly saved. By applying some improved slack inequalities and an augmented Lyapunov–Krasovskii functional (LKF), a new design condition expressed in the form of linear matrix inequalities (LMIs) is developed to derive the desired event-triggered controller. The obtained algorithm is then employed to solve the static output-feedback control gain. Compared with the traditional sampled-data 〈em〉H〈/em〉〈sub〉∞〈/sub〉 control scheme, the proposed controller is able to provide an enhanced disturbance attenuation level while saving the control cost. Finally, comparative simulation results are provided to show the performance of the proposed event-triggered controller.〈/p〉〈/div〉

Description: 〈p〉Publication date: March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Mathematical Analysis and Applications, Volume 471, Issues 1–2〈/p〉 〈p〉Author(s): Xie Li, Yilong Wang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This paper is devoted to the following fully parabolic chemotaxis system with Lotka–Volterra competitive kinetics〈span〉〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si1.gif" overflow="scroll"〉〈mrow〉〈mo stretchy="true"〉{〈/mo〉〈mtable displaystyle="true" columnspacing="0.2em"〉〈mtr〉〈mtd columnalign="right"〉〈/mtd〉〈mtd columnalign="left"〉〈msub〉〈mrow〉〈mi〉u〈/mi〉〈/mrow〉〈mrow〉〈mi〉t〈/mi〉〈/mrow〉〈/msub〉〈mo〉=〈/mo〉〈mi mathvariant="normal"〉Δ〈/mi〉〈mi〉u〈/mi〉〈mo〉−〈/mo〉〈msub〉〈mrow〉〈mi〉χ〈/mi〉〈/mrow〉〈mrow〉〈mn〉1〈/mn〉〈/mrow〉〈/msub〉〈mi mathvariant="normal"〉∇〈/mi〉〈mo〉⋅〈/mo〉〈mo stretchy="false"〉(〈/mo〉〈mi〉u〈/mi〉〈mi mathvariant="normal"〉∇〈/mi〉〈mi〉w〈/mi〉〈mo stretchy="false"〉)〈/mo〉〈mo〉+〈/mo〉〈msub〉〈mrow〉〈mi〉μ〈/mi〉〈/mrow〉〈mrow〉〈mn〉1〈/mn〉〈/mrow〉〈/msub〉〈mi〉u〈/mi〉〈mo stretchy="false"〉(〈/mo〉〈mn〉1〈/mn〉〈mo〉−〈/mo〉〈mi〉u〈/mi〉〈mo〉−〈/mo〉〈msub〉〈mrow〉〈mi〉a〈/mi〉〈/mrow〉〈mrow〉〈mn〉1〈/mn〉〈/mrow〉〈/msub〉〈mi〉v〈/mi〉〈mo stretchy="false"〉)〈/mo〉〈mo〉,〈/mo〉〈mspace width="2em"〉〈/mspace〉〈/mtd〉〈mtd columnalign="right"〉〈mi〉x〈/mi〉〈mo〉∈〈/mo〉〈mi mathvariant="normal"〉Ω〈/mi〉〈mo〉,〈/mo〉〈mspace width="0.2em"〉〈/mspace〉〈mi〉t〈/mi〉〈mo〉〉〈/mo〉〈mn〉0〈/mn〉〈mo〉,〈/mo〉〈/mtd〉〈/mtr〉〈mtr〉〈mtd columnalign="right"〉〈/mtd〉〈mtd columnalign="left"〉〈msub〉〈mrow〉〈mi〉v〈/mi〉〈/mrow〉〈mrow〉〈mi〉t〈/mi〉〈/mrow〉〈/msub〉〈mo〉=〈/mo〉〈mi mathvariant="normal"〉Δ〈/mi〉〈mi〉v〈/mi〉〈mo〉−〈/mo〉〈msub〉〈mrow〉〈mi〉χ〈/mi〉〈/mrow〉〈mrow〉〈mn〉2〈/mn〉〈/mrow〉〈/msub〉〈mi mathvariant="normal"〉∇〈/mi〉〈mo〉⋅〈/mo〉〈mo stretchy="false"〉(〈/mo〉〈mi〉v〈/mi〉〈mi mathvariant="normal"〉∇〈/mi〉〈mi〉w〈/mi〉〈mo stretchy="false"〉)〈/mo〉〈mo〉+〈/mo〉〈msub〉〈mrow〉〈mi〉μ〈/mi〉〈/mrow〉〈mrow〉〈mn〉2〈/mn〉〈/mrow〉〈/msub〉〈mi〉v〈/mi〉〈mo stretchy="false"〉(〈/mo〉〈mn〉1〈/mn〉〈mo〉−〈/mo〉〈mi〉v〈/mi〉〈mo〉−〈/mo〉〈msub〉〈mrow〉〈mi〉a〈/mi〉〈/mrow〉〈mrow〉〈mn〉2〈/mn〉〈/mrow〉〈/msub〉〈mi〉u〈/mi〉〈mo stretchy="false"〉)〈/mo〉〈mo〉,〈/mo〉〈mspace width="2em"〉〈/mspace〉〈/mtd〉〈mtd columnalign="right"〉〈mi〉x〈/mi〉〈mo〉∈〈/mo〉〈mi mathvariant="normal"〉Ω〈/mi〉〈mo〉,〈/mo〉〈mspace width="0.2em"〉〈/mspace〉〈mi〉t〈/mi〉〈mo〉〉〈/mo〉〈mn〉0〈/mn〉〈mo〉,〈/mo〉〈/mtd〉〈/mtr〉〈mtr〉〈mtd columnalign="right"〉〈/mtd〉〈mtd columnalign="left"〉〈msub〉〈mrow〉〈mi〉w〈/mi〉〈/mrow〉〈mrow〉〈mi〉t〈/mi〉〈/mrow〉〈/msub〉〈mo〉=〈/mo〉〈mi mathvariant="normal"〉Δ〈/mi〉〈mi〉w〈/mi〉〈mo〉−〈/mo〉〈mi〉λ〈/mi〉〈mi〉w〈/mi〉〈mo〉+〈/mo〉〈msub〉〈mrow〉〈mi〉b〈/mi〉〈/mrow〉〈mrow〉〈mn〉1〈/mn〉〈/mrow〉〈/msub〉〈mi〉u〈/mi〉〈mo〉+〈/mo〉〈msub〉〈mrow〉〈mi〉b〈/mi〉〈/mrow〉〈mrow〉〈mn〉2〈/mn〉〈/mrow〉〈/msub〉〈mi〉v〈/mi〉〈mo〉,〈/mo〉〈mspace width="2em"〉〈/mspace〉〈/mtd〉〈mtd columnalign="right"〉〈mi〉x〈/mi〉〈mo〉∈〈/mo〉〈mi mathvariant="normal"〉Ω〈/mi〉〈mo〉,〈/mo〉〈mspace width="0.2em"〉〈/mspace〉〈mi〉t〈/mi〉〈mo〉〉〈/mo〉〈mn〉0〈/mn〉〈mo〉,〈/mo〉〈/mtd〉〈/mtr〉〈/mtable〉〈/mrow〉〈/math〉〈/span〉 under homogeneous Neumann boundary conditions, where 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si2.gif" overflow="scroll"〉〈mi mathvariant="normal"〉Ω〈/mi〉〈mo〉⊂〈/mo〉〈msup〉〈mrow〉〈mi mathvariant="double-struck"〉R〈/mi〉〈/mrow〉〈mrow〉〈mi〉n〈/mi〉〈/mrow〉〈/msup〉〈/math〉 is a bounded domain with smooth boundary. We mainly consider the global existence and boundedness of classical solutions in the three dimensional case, which extends and partially improves the results of Bai–Winkler (2016) [1], Xiang (2018) [25], as well as Lin–Mu–Wang (2015) [10], etc.〈/p〉〈/div〉

Description: 〈p〉Publication date: April 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Mathematics Letters, Volume 90〈/p〉 〈p〉Author(s): Chuan-Qi Su, Yong-Yan Wang, Nan Qin, Jian-Guang Li, Guo-Dong Zhang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A nonintegrable Korteweg–de Vries equation with variable coefficients is investigated in this paper. Due to the existence of variable coefficients, the equation becomes nonintegrable, which leads to the invalidity of the traditional analytical methods to obtain soliton solutions. In order to overcome this difficulty, the variational approach is employed in this paper. The variational principle corresponding to this nonintegrable equation is established. Based on that, the first- and second-order nonautonomous soliton solutions are derived. We note that the obtained solutions can be degenerated to the integrable cases. Properties of the nonautonomous solitons and influence of the variable coefficients are discussed.〈/p〉〈/div〉

Description: 〈p〉Publication date: 7 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Advances in Mathematics, Volume 341〈/p〉 〈p〉Author(s): Laura Anderson, James F. Davis〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In a recent paper Baker and Bowler introduced matroids over hyperfields, offering a common generalization of matroids, oriented matroids, and linear subspaces of based vector spaces. This paper introduces the notion of a topological hyperfield and explores the generalization of Grassmannians and realization spaces to this context, particularly in relating the (hyper)fields 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si1.gif" overflow="scroll"〉〈mi mathvariant="double-struck"〉R〈/mi〉〈/math〉 and 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si2.gif" overflow="scroll"〉〈mi mathvariant="double-struck"〉C〈/mi〉〈/math〉 to hyperfields arising in matroid theory and in tropical geometry.〈/p〉〈/div〉

Description: 〈p〉Publication date: 7 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Advances in Mathematics, Volume 341〈/p〉 〈p〉Author(s): Andrew R. Booker, Micah B. Milinovich, Nathan Ng〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Modifying a method of Jutila, we prove a 〈em〉t〈/em〉-aspect subconvexity estimate for 〈em〉L〈/em〉-functions associated to primitive holomorphic cusp forms of arbitrary level that is of comparable strength to Good's bound for the full modular group, thus improving on a 36-year-old result. A key innovation in our proof is a general form of Voronoi summation that applies to all fractions, even when the level is not squarefree.〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Geomorphology, Volume 327〈/p〉 〈p〉Author(s): Fei Yan, Qiuwen Zhang, Song Ye, Bo Ren〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Landslides, which could cause huge losses of lives or property damages, result from several different environmental factors whose influences on landslides are very complex. Therefore, it is essential to understand the relationships between these environmental factors and landslides. Thus, the integration of the analytical hierarchy process (AHP) with the normalized frequency ratio (NFR) is evaluated for landslide susceptibility analyses. However, in addition to these complex relationships, the randomness and fuzziness always affect landslide susceptibility mapping. This study introduces the cloud model (CM) to improve the integrated AHP-NFR method, and proposes a novel hybrid AHP-NFR-CM method for landslide susceptibility analyses, which can better address issues of the randomness and fuzziness. Firstly, ten environmental parameters are selected as landslide impact factors, and their values for all the landslides identified in the study area are obtained through the remote sensing (RS) and geographical information system (GIS) technologies. The AHP method is used to obtain the weight of each landslide impact factor, and the NFR method is used to obtain the weight of each subclass in each landslide impact factor, which can reflect the relationship between the landslide impact factor and landslide occurrence. After applying an appropriate compositional operation between the weights of the landslide impact factors and the weights of the subclasses of the impact factors, a landslide susceptibility index (LSI) for each grid divided via the attribution-based spatial information multi-grid method (ASIMG) can be computed. To solve the inevitable issues of randomness and fuzziness in landslide susceptibility analyses, a cloud model that uses three numerical features (expectation, entropy and hyper-entropy) to represent the intension of the concept, is adopted to improve the methods of AHP and NFR. The relative importance of two landslide impact factors is scaled with the cloud model rather than the Saaty criteria. Pair-wise comparison matrixes of landslide impact factors given by each expert are described by the normal cloud model, and the floating cloud model is used to aggregate all experts' judgments. The weight of each landslide impact factor is also expressed with the cloud model rather than a certain value. In improving the NFR, the weight of each subclass of each landslide impact factor is expressed with the cloud model rather than a certain value. In the improvement of the landslide susceptibility results, the domain of landslide risk assessment results is also displayed with the cloud model instead of a series of definite intervals. As the study area examined is large, several grids would need to be divided, meaning that it would take a considerable amount time to subject the entire study area to landslide susceptibility mapping. Thus, we propose a new attribute-based spatial information multi-grid (ASIMG) division method and introduce grid-computing technology to improve the calculation efficiency during the process. Finally, the proposed hybrid AHP-NFR-CM-ASIMG approach is validated and applied in the study area. It's concluded that the new integration of AHP and NFR methods with the cloud model can consider both randomness and fuzziness and therefore can increase the robustness of landslide susceptibility analyses, while the ASIMG technology can enhance the calculation efficiency in regional landslide susceptibility mapping.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology, Volume 568〈/p〉 〈p〉Author(s): Shanshan Deng, Junqiang Xia, Meirong Zhou, Fenfen Lin〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Recent significant channel evolution in the Jingjiang Reach has raised much attention, particularly the remarkable bank erosion. A coupled model for simulating bed deformation and bank erosion has been proposed in this study, which focuses on the erosion of the bank with a composite structure in the Lower Jingjiang Reach. In order to cover three contributing processes that may interact with each other, the proposed model integrates a one-dimensional morphodynamic module with a two-dimensional module of ground water flow and a bank erosion module for the cantilever failure of a composite riverbank. Model performance was evaluated through a detailed simulation of channel evolution along a 150.8-km subreach in the Jingjiang Reach over the 2005 hydrological year. Satisfying results were obtained from the simulation, showing relatively close agreement between the calculations and measurements in terms of hydrological data at the outlet section, bank erosion sites, longitudinal channel profile and typical cross-sectional profiles. In addition, investigations into temporal changes in bank soil properties and critical overhanging width at cantilever failure demonstrate that there was a seasonal variation in the volumetric water content of bank soil, which increased during the rising and flood periods and then decreased during the recession period, showing an impact on the occurrence timing of cantilever failures. The tensile strength and critical overhanging width had an inverse relationship with the water content, whereas the critical width sharply increased and then decreased during high flows affected by a rapid change in river stage. The temporal distribution of cantilever failure events indicates that cantilever failure primarily occurred in the flood and recession periods. The effects of bed roughness, water content variation and secondary flow on bank erosion were also discussed.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology, Volume 568〈/p〉 〈p〉Author(s): M. Esteves, C. Legout, O. Navratil, O. Evrard〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉In mountainous catchments, soil erosion and sediment transport are highly variable throughout time and their quantification remains a major challenge for the scientific community. Understanding the temporal patterns and the main controls of sediment yields in these environments requires a long term monitoring of rainfall, runoff and sediment flux. This paper analyses this type of data collected during 7 years (2007–2014), at the outlet of the Galabre River, a 20 km〈sup〉2〈/sup〉 watershed, in south eastern France, representative of meso-scale Mediterranean mountainous catchments.〈/p〉 〈p〉This study is based on a hybrid approach using continuous turbidity records and automated total suspended solid sampling to quantify the instantaneous suspended sediment concentrations (SSC), sediment fluxes, event loads and yields. The total suspended sediment yield was 4661 Mg km〈sup〉−2〈/sup〉 and was observed during flood events. The two crucial periods for suspended sediment transport at the outlet were June and November/December (63% of the total). The analysis of suspended sediment transport dynamics observed during 236 flood events highlighted their intermittency and did not show any clear relationship between rainfall, discharge and SSC. The most efficient floods were characterised by counter-clockwise hysteresis relationships between SSC and discharges. The floods with complex hysteresis were the more productive in the long term, during this measuring period exceeding a decade. Nevertheless, the current research outlines the need to obtain medium-term (five years) continuous time series to assess the range of variations of suspended sediment fluxes and to outline clearly the seasonality of suspended sediment yields. Results suggest the occurrence of a temporal dis-connectivity in meso-scale catchments over short time-scales between the meteorological forcing and the sediment yields estimated at the outlet. These findings have important methodological impacts for modelling and operational implications for watershed management.〈/p〉 〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Agricultural and Forest Meteorology, Volume 264〈/p〉 〈p〉Author(s): Antonio D. del Campo, María González-Sanchis, Alberto García-Prats, Carlos J. Ceacero, Cristina Lull〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Marginal semi-arid forests in areas currently affected by climate change are a challenge to forest management, which has to focus on key functional traits that can effectively contribute to resistance under extreme drought. We studied the effects of thinning in a marginal forest by quantifying functional responses relating to growth, carbon and water fluxes. Two experimental plots were established, one thinned in 2012 and the other one left as a control. The environmental conditions varied substantially during the 4-year study period, although dry years predominated. There were signs of dieback in the control with a decreasing inter-annual trend in LAI, as opposed to the treated plots, where LAI by the end of the study almost reached pre-thinning levels. Sap flow and transpiration were greatly enhanced by the treatment, with thinned trees transpiring 22.4 l tree〈sup〉−1〈/sup〉 day〈sup〉−1〈/sup〉 in the growing season, about twice the control figures. The seasonal patterns of transpiration and soil moisture were uncoupled, indicating a contribution of deep groundwater to the former flux. In the control, limitations to water and carbon dynamics (canopy conductance) occurred at soil moisture values below 16%, whereas in the thinned trees these limitations appeared when soil moisture dropped below 10%. Overall, oaks’ transpiration was enhanced with thinning to the point that stand-water use surpassed that of the control by the second half of the study period, averaging 24% of gross rainfall in both plots. Soil evaporation increased from 12 to 20% of gross rainfall after treatment in the overall period. The treatment had a profound watering effect in this marginal forest, led by fewer trees using the same amount of water as those in the untreated overstocked plot. This research may provide guidelines for ecohydrology-oriented silviculture in stands experiencing tree encroachment and transformation into shrublands that are more prone to global change-induced disturbances.〈/p〉〈/div〉

Description: 〈p〉Publication date: December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Transport Geography, Volume 73〈/p〉 〈p〉Author(s): Amparo Moyano, Borja Moya-Gómez, Javier Gutiérrez〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Accessibility by high-speed rail (HSR) depends not only on station-to-station travel time, but also on access and egress times, which can be determining factors in total journey travel time. However, studies focusing on accessibility analyses of access/egress times to/from stations are less extended in the literature and centre mainly on the influence of access times to stations on HSR accessibility levels on a regional scale. This paper's aim is to evaluate the importance of access and egress times to/from HSR stations in an urban context. We carry out a spatiotemporal accessibility analysis that considers the temporal variations of both taxi and public transport travel times. General Transit Feed Specification (GTFS) files for public transport and TomTom Speed Profiles data for cars are used to measure access/egress times. These kinds of data allow for the calculation of travel times from/to HSR stations through network analysis GIS tools at different times of the day, and thus a spatiotemporal accessibility measure can be obtained. This accessibility measure is complemented by a mass factors representing the activity ‘hotspots’ in the visited city throughout the workday, which is derived from Twitter data, while population is considered for city of residence. This method was applied to the two largest metropolitan areas in Spain: Madrid and Barcelona, where the influence of access/egress times acquires a higher relevance for rail-based trips. The results obtained show that access and egress times vary significantly during the day, depending on the levels of traffic congestion and the frequency of public transport services, which are always more favourable for taxis. In addition, weighted average access and egress times at the home end are higher than those at the activity end since population tends to show more dispersed spatial patterns than activities. Another interesting finding is that the first and last mile of the HSR trip usually account for a high percentage increase in travel time (about 35% for taxis and 55% for public transport, respectively). These results have important policy implications. The paper suggests that HSR accessibility can be improved also by improving local transport services, scheduling coordination and land use policies.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Agricultural and Forest Meteorology, Volume 264〈/p〉 〈p〉Author(s): Ren Li, Lin Zhao, Tonghua Wu, Qinxue Wang, Yongjian Ding, Jimin Yao, Xiaodong Wu, Guojie Hu, Yao Xiao, Yizhen Du, Xiaofan Zhu, Yanhui Qin, Shuhua Yang, Rui Bai, Erji Du, Guangyue Liu, Defu Zou, Yongping Qiao, Jianzong Shi〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Soil thermal conductivity (〈em〉λ〈/em〉) is one of the essential parameters relating to heat exchange, and it also plays a key role in verifying soil thermal hydrodynamics in permafrost regions. In this paper, the characteristic of in situ 〈em〉λ〈/em〉 was analyzed based on data measured from June 2004 to December 2008 at Tanggula district on the Qinghai–Tibet Plateau. The result showed that diurnal 〈em〉λ〈/em〉 strongly influenced by variation of soil moisture content. The daily 〈em〉λ〈/em〉 exhibited distinct seasonal variation; on average, the largest value of 〈em〉λ〈/em〉 occurred in summer, followed by the autumn and spring season, while the smallest value occurred in winter. As a whole, 〈em〉λ〈/em〉 values in the unfrozen state were larger than those in the frozen state. Unsaturated soil and the huge difference in soil moisture content between the unfrozen state and initial freeze resulted in the lower 〈em〉λ〈/em〉 in the frozen state. For the study area, the critical value of local soil saturation degree was about 0.37, the corresponding critical soil moisture content was about 0.195 m〈sup〉3〈/sup〉 m〈sup〉−3〈/sup〉. And soil moisture content was the main factor controlling in situ 〈em〉λ〈/em〉. Finally, an empirically-derived model was proposed for predicting daily 〈em〉λ〈/em〉, and which showed good performance in the study area.〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Agricultural and Forest Meteorology, Volume 264〈/p〉 〈p〉Author(s): Baoqing Zhang, Amir AghaKouchak, Yuting Yang, Jiahua Wei, Guangqian Wang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Different categories of droughts (e.g., meteorological, agricultural, hydrological), and their multi-scalar features often make description of drought onset, persistence, and termination challenging and often subjective. Here we show that a water-energy balance based indicator, named Standardized Moisture Anomaly Index (SZI), better captures multiple categories of droughts and their multi-scalar features. We globally evaluate and compare the performance of SZI with existing drought indicators that use potential evapotranspiration (PET) as a measure of atmospheric water demand including the Standardized Precipitation Evapotranspiration Index (SPEI) and self-calibrated Palmer Drought Severity Index (scPDSI). We show that while 〈em〉PET〈/em〉 is a good indicator for characterizing the climate aridity, using it as a measure of atmospheric water demand for drought analysis leads to misrepresentation of droughts, especially over water-limited (non-humid) regions where the actual evapotranspiration is primarily dominated by water availability rather than energy (or PET). The main advantage of SZI is that, instead of PET, it uses a variable termed climatically appropriate precipitation for existing conditions (〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si2.gif" overflow="scroll"〉〈mover accent="true"〉〈mi〉P〈/mi〉〈mo〉ˆ〈/mo〉〈/mover〉〈/math〉) as the atmospheric water demand metric. Investigating droughts over 32 large basins across the globe, we show that the SZI can better represent meteorological, hydrological, and agricultural droughts compared to SPEI (especially in non-humid basins; 18 out of 32 basins) and scPDSI at multiple time scales. Given that SZI is physically more reasonable in reflecting surface water-energy balance over both humid and non-humid regions, it enables better characterization of different types of droughts in different climatic regions.〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Geomorphology, Volume 327〈/p〉 〈p〉Author(s): Chenge An, Gary Parker, Marwan A. Hassan, Xudong Fu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Massive bed degradation (20 m in 7 years) has been observed in the Shi‑ting River, Sichuan Province, China, since the 2008 Wenchuan Ms. 8.0 earthquake. The reason for the massive bed degradation has not been well understood. A hypothesis has been proposed that relates bed degradation to the augmentation of sand supply after the earthquake. The effect of sand on gravel mobility (〈em〉magic sand〈/em〉 effect) has long been observed in laboratory experiments. In this paper, we study whether the augmentation of sand supply and its 〈em〉magic sand〈/em〉 effect can lead to the observed massive degradation at decadal scales. A one-dimensional river morphodynamic model is implemented to study the problem in general at field scale and in context of the gravel-bed Shi‑ting River. Sediment transport is calculated with the Wilcock and Crowe (2003) relation, in which the 〈em〉magic sand〈/em〉 effect is explicitly embedded in terms of a function relating reference Shields number to the surface sand fraction. We find that the augmentation of gravel supply leads to bed aggradation, whereas the augmentation of sand supply can indeed lead to bed degradation and surface fining. The magnitude and timescale of bed degradation are not sensitive to the sand supply rate but are sensitive to the flood intermittency factor〈sub〉,〈/sub〉 i.e., the fraction of time the river is in flood. However, an unrealistic flood intermittency factor (≥0.3) would be required in order to match the observed timescale of bed degradation, thus indicating that the 〈em〉magic sand〈/em〉 effect might not be the governing reason for massive bed degradation in the Shi‑ting River, and by implication in gravel-bed rivers in general. Our simulation results also indicate that despite the fact that 〈em〉magic sand〈/em〉 effects are not explicitly included in most sediment transport relations, they are at least partly built in via the hiding function that is contained in most sediment transport relations for gravel-sand mixtures. While here we use the Shi‑ting River as an example, our results have applicability to gravel-bed rivers subjected to augmentation in sand supply in general.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Geomorphology, Volume 327〈/p〉 〈p〉Author(s): Hakan Tanyas, Mauro Rossi, Massimiliano Alvioli, Cees J. van Westen, Ivan Marchesini〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Rapid assessment of spatial distribution of earthquake-induced landslides could provide valuable information in the emergency response phase. Previous studies proposed global analyses with the aim of predicting earthquake-induced landslide distributions in near real-time. However, in all those studies, mapping units are constituted by pixels, which do not reflect homogeneously distributed physical property for a given terrain unit and whose size do not match the resolution of existing thematic data at global scale. Moreover, none of the existing analyses considers sampling balance between different inventories or categorizing the inventories to construct a training set with higher statistical representativeness. We develop an improved global statistical method to address these drawbacks. We use slope units, which are terrain partitions attributed to similar hydrological and geomorphological conditions and to processes that shape natural landscapes. A set of 25 earthquake-induced landslide-events are selected and categorized based on the similarity between causal factors to determine the most relevant training set to make a prediction for a given landslide-event. As a result, we develop a specific model for each category. We sample an equal number of landslide points from each inventory to overcome the dominance of some inventories with large landslide population. We use seven independent thematic variables for both categorizing the inventories and modeling, based on logistic regression. The results show that categorizing landslide-events introduces a remarkable improvement in the modeling performance of many events. The categorization of existing inventories can be applied within any statistical, global approach to earthquake-induced landslide events. The proposed categorization approach and the classification performance can be further improved with the acquisition of new inventory maps.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Remote Sensing of Environment, Volume 220〈/p〉 〈p〉Author(s): F.J.A. van Ruitenbeek, H.M.A. van der Werff, W.H. Bakker, F.D. van der Meer, K.A.A. Hein〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉A novel method is presented to measure rock microstructure in hyperspectral mineral maps of rock specimens. Shape parameters were calculated from rock objects in segmented mineral maps. Object area, object perimeter, object hull perimeter and fitted ellipses were used to calculate shape parameters such as compactness, convexity and a cookie-cutter parameter. Shape parameters were used to describe a variety of microstructures and microstructural elements. The parameters were tested on microstructures in artificial imagery and subsequently applied to hyperspectral mineral maps of rocks.〈/p〉 〈p〉Analyses of parameters calculated on artificial imagery showed that object shapes could be measured by the flattening of fitted ellipses as a measure of sphericity and elongation, together with the cookie-cutter parameters that measured angularity. Compactness and convexity could differentiate between euhedral, subhedral and anhedral crystal shapes. Aphanitic, phaneritic and porphyritic igneous microstructures could be identified and differentiated by homogeneity and relative object size parameters. The degree of sorting of sedimentary rocks was measured by the distribution of object sizes and statistical parameters describing the distribution. Orientation of single objects was measured by the angle between the major axis of a fitted ellipse and the vertical of the image. Preferred orientations in the rock microstructure were determined by calculation of a standardized resultant of orientation vectors and a mean angle. Layering and banding of the rock was identified by the length of major axes of fitted ellipses relative to the image dimension.〈/p〉 〈p〉The shape parameters calculated on objects in segmented hyperspectral mineral maps of rock specimens were able to discriminate between sedimentary and volcanic microstructures using the size distribution of mineral objects, the presence of a preferred orientation of the rock and a layered microstructure. The volcanic microstructures could be differentiated by the size distribution of amygdales, phenocrysts and xenocrysts in the rock. Shape parameters could be used to differentiate between xenocrysts and phenocrysts, the latter being more elongated in the studied samples.〈/p〉 〈p〉The study shows that object shape parameters can be used to measure microstructure and microstructural elements in mineral maps, and subsequently discriminate between different rock types and microstructures. The expression of microstructure into numeric parameters is a first step towards quantification of microstructures in mineral maps of rocks. Further development of the methodology could contribute to the creation of unbiased classification scheme of rocks, improved statistical modeling of compositional rock parameters such as mineral ore grades, and the automated recognition of microstructures in large image databases of rocks and drill-core.〈/p〉 〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S003442571830484X-ga1.jpg" width="314" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Agricultural and Forest Meteorology, Volume 264〈/p〉 〈p〉Author(s): Ravshan Eshonkulov, Arne Poyda, Joachim Ingwersen, Alim Pulatov, Thilo Streck〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Turbulent fluxes at the land surface measured by the Eddy Covariance (EC) technique are typically considerably less than the difference between net radiation and ground heat flux. This is known as the energy balance closure (EBC) problem. It is crucial for validating land surface models as it provokes substantial uncertainty to the magnitude and partitioning of energy fluxes. The gap in the energy balance calls for searching for additional energy terms in the soil-plant-atmosphere system. To evaluate the contribution of these minor storage terms to the measured EBC, we conducted an experimental study to evaluate the contribution of these minor storage terms to measured EBC in the Kraichgau region in southwest Germany over two consecutive growing seasons (2015 and 2016). The measured and calculated minor storage terms comprised the enthalpy change in the plant canopy (〈em〉S〈sub〉c〈/sub〉〈/em〉), the air enthalpy change (〈em〉S〈sub〉a〈/sub〉〈/em〉), the energy consumption and release by photosynthesis and respiration (〈em〉S〈sub〉p〈/sub〉〈/em〉), and the atmospheric moisture change (〈em〉S〈sub〉q〈/sub〉〈/em〉). Furthermore, the soil heat storage (〈em〉S〈sub〉g〈/sub〉〈/em〉) was determined at different locations within the EC footprint and compared to the single point measurements of 〈em〉S〈sub〉g〈/sub〉〈/em〉 at the EC station. Calorimetric and harmonic analysis were performed to compute ground heat flux. 〈em〉S〈sub〉p〈/sub〉〈/em〉 had the strongest effect in improving EBC due to the high net CO〈sub〉2〈/sub〉 uptake during the productive phase of plant growth. In 2015, all minor storage terms together increased EBC by 5.0% on average, with a maximum value of 7.4% in May, while the improvement in 2016 was 6.8% on average and 8.4% in May. Ground heat flux computed with the harmonic analysis based on plate data narrowed the EBC by 3% more than the calorimetric method. In summary, a better EBC can be achieved by considering minor storage terms and applying a harmonic analysis to ground heat flux data. Regarding future research, we recommend to focus on year-round measurements of energy terms because energy stored during the growing season might be lost from the system during the rest of the year. Nonetheless, the significant contribution of minor energy terms to EBC indicates that turbulent energy fluxes are most likely overestimated when all the missing energy is assumed to be turbulent–the typical approach when fluxes are corrected by the Bowen ratio post-closure method for instance.〈/p〉〈/div〉

Description: 〈p〉Publication date: December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 ISPRS Journal of Photogrammetry and Remote Sensing, Volume 146〈/p〉 〈p〉Author(s): Jean-François Tremblay, Martin Béland〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Terrestrial laser scanning (TLS) often makes use of multiple scans in forests to allow for a complete view of a given area. Combining measurements from multiple locations requires accurate co-registration of the scans to a common reference coordinate system, which currently relies on markers, an often cumbersome process in forests. Existing algorithms for achieving marker-free registration of TLS scans in forests promise to significantly decrease field work time, but are not yet operational and their results have not been validated against traditional methods. Here we present a new implementation of an existing approach which runs in parallel mode and is able to process TLS data acquired over large forest areas. To validate our algorithm, point cloud registration matrices (translation and rotation) derived from our algorithm were compared to those obtained using reflective markers in multiple forest types. The results show that our approach can be used operationally in forests with relatively clear understory, and it provides accuracy similar to that obtained from using reflective markers. Furthermore, we identified factors that can lead to this approach falling short of providing acceptable results in terms of accuracy.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Agricultural and Forest Meteorology, Volume 264〈/p〉 〈p〉Author(s): Adrià Barbeta, J. Julio Camarero, Gabriel Sangüesa-Barreda, Lena Muffler, Josep Peñuelas〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The performance and persistence of rear-edge tree populations are relevant issues for conserving biodiversity because these stands harbor high intraspecific biodiversity and play a key role during periods of climate change. The occurrence of these populations is associated with the influence of heterogeneous topography, creating suitable refugia with regionally rare environmental conditions. Climate is changing at a global-scale, but little is known about the long-term impact on local climatic singularities and the associated taxa. We analyzed tree-ring growth chronologies of the two species (〈em〉Fagus sylvatica〈/em〉 and 〈em〉Quercus ilex〈/em〉) forming the evergreen-deciduous forest ecotone, constitutive of the rear-edge of 〈em〉F. sylvatica〈/em〉 distribution. The study area is a coastal range with frequent fog immersion, which has been hypothesized to favor the persistence of 〈em〉F. sylvatica〈/em〉 in Mediterranean peninsulas. We analyzed the long-term effect of fog on tree growth along a topographical gradient and the sensitivity of growth to rainfall and temperature. The annual number of foggy days has decreased by 62% over the last four decades, concomitant with increasing temperatures. Fog frequency was a relevant factor determining tree growth; fog during summer had positive effects on 〈em〉F. sylvatica〈/em〉 growth mainly through a temperature buffering effect. The positive effect of fog on the growth of 〈em〉Q. ilex〈/em〉, however, was likely caused by a collinearity with rainfall. 〈em〉Q. ilex〈/em〉 growth was less sensitive to climate than 〈em〉F. sylvatica〈/em〉, but growth of both species was enhanced by a positive early-summer water balance. Our results indicate that a decrease in fog frequency and an increase in temperature may generally benefit 〈em〉Q. ilex〈/em〉 in this forest ecotone. Although future changes in rainfall and temperature matter most for the fate of rear-edge tree populations, local climatic singularities such as fog should also be considered. Those can have complementary effects that can swing the balance in ecotones and rear-edge tree populations such as those studied here.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0168192318303447-ga1.jpg" width="269" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Differential Equations, Volume 266, Issue 1〈/p〉 〈p〉Author(s): Wanrong Yang, Quansen Jiu, Jiahong Wu〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The magnetohydrodynamic (MHD) equations have played pivotal roles in the study of many phenomena in geophysics, astrophysics, cosmology and engineering. The fundamental problem of whether or not classical solutions of the 3D MHD equations can develop finite-time singularities remains an outstanding open problem. Mathematically this problem is supercritical in the sense that the 3D MHD equations do not have enough dissipation. If we replace the standard velocity dissipation Δ〈em〉u〈/em〉 and the magnetic diffusion Δ〈em〉b〈/em〉 by 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si1.gif" overflow="scroll"〉〈mo〉−〈/mo〉〈msup〉〈mrow〉〈mo stretchy="false"〉(〈/mo〉〈mo〉−〈/mo〉〈mi mathvariant="normal"〉Δ〈/mi〉〈mo stretchy="false"〉)〈/mo〉〈/mrow〉〈mrow〉〈mi〉α〈/mi〉〈/mrow〉〈/msup〉〈mi〉u〈/mi〉〈/math〉 and 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si2.gif" overflow="scroll"〉〈mo〉−〈/mo〉〈msup〉〈mrow〉〈mo stretchy="false"〉(〈/mo〉〈mo〉−〈/mo〉〈mi mathvariant="normal"〉Δ〈/mi〉〈mo stretchy="false"〉)〈/mo〉〈/mrow〉〈mrow〉〈mi〉β〈/mi〉〈/mrow〉〈/msup〉〈mi〉b〈/mi〉〈/math〉, respectively, the resulting equations with 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si3.gif" overflow="scroll"〉〈mi〉α〈/mi〉〈mo〉≥〈/mo〉〈mfrac〉〈mrow〉〈mn〉5〈/mn〉〈/mrow〉〈mrow〉〈mn〉4〈/mn〉〈/mrow〉〈/mfrac〉〈/math〉 and 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si4.gif" overflow="scroll"〉〈mi〉α〈/mi〉〈mo〉+〈/mo〉〈mi〉β〈/mi〉〈mo〉≥〈/mo〉〈mfrac〉〈mrow〉〈mn〉5〈/mn〉〈/mrow〉〈mrow〉〈mn〉2〈/mn〉〈/mrow〉〈/mfrac〉〈/math〉 then always have global classical solutions. An immediate issue is whether or not the hyperdissipation can be further reduced. This paper shows that the global regularity still holds even if there is only directional velocity dissipation and horizontal magnetic diffusion 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si5.gif" overflow="scroll"〉〈mo〉−〈/mo〉〈msup〉〈mrow〉〈mo stretchy="false"〉(〈/mo〉〈mo〉−〈/mo〉〈msub〉〈mrow〉〈mi mathvariant="normal"〉Δ〈/mi〉〈/mrow〉〈mrow〉〈mi〉h〈/mi〉〈/mrow〉〈/msub〉〈mo stretchy="false"〉)〈/mo〉〈/mrow〉〈mrow〉〈mfrac〉〈mrow〉〈mn〉5〈/mn〉〈/mrow〉〈mrow〉〈mn〉4〈/mn〉〈/mrow〉〈/mfrac〉〈/mrow〉〈/msup〉〈mi〉b〈/mi〉〈/math〉, where 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si6.gif" overflow="scroll"〉〈msub〉〈mrow〉〈mi mathvariant="normal"〉Δ〈/mi〉〈/mrow〉〈mrow〉〈mi〉h〈/mi〉〈/mrow〉〈/msub〉〈mo〉=〈/mo〉〈msubsup〉〈mrow〉〈mo〉∂〈/mo〉〈/mrow〉〈mrow〉〈mn〉1〈/mn〉〈/mrow〉〈mrow〉〈mn〉2〈/mn〉〈/mrow〉〈/msubsup〉〈mo〉+〈/mo〉〈msubsup〉〈mrow〉〈mo〉∂〈/mo〉〈/mrow〉〈mrow〉〈mn〉2〈/mn〉〈/mrow〉〈mrow〉〈mn〉2〈/mn〉〈/mrow〉〈/msubsup〉〈/math〉.〈/p〉〈/div〉

Description: 〈p〉Publication date: December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Dynamics of Atmospheres and Oceans, Volume 84〈/p〉 〈p〉Author(s): A. Lugo-Fernández〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The Loop Current (LC) intrusion into the Gulf of Mexico is analyzed using steady, 2-D nonlinear shallow water equations expressed in Cartesian and natural coordinates. The model suggests that the LC moves with constant relative vorticity along isopleths of the Bernoulli function B such that its surface area (A) has a steady dA/dt and frontal velocity. The intrusion is envisioned as an initial transport imbalance that creates volume storage within the Gulf. Because of the advection of relative vorticity, the intruding inflow splits into a northward flow on the west and a southward flow on the east. The storage creates a sea level difference across the LC that induces a northward force due to Coriolis. This force reinforces the northward flow but opposes the southward flow, helping store water inside the Gulf. This sea level difference is in addition to the one in the B field. The storage implies loss of kinetic energy, which creates a speed shear across the LC and gives rise to the small speed of the LC front. The relative vorticity equation in natural coordinates reveals three aspects of the LC: (1) a velocity difference across the LC, (2) a parabolic shape of the sea surface; and (3) a negative curvature of the LC meaning the velocity changes direction anticyclonically along the B-contours.〈/p〉〈/div〉

Description: 〈p〉Publication date: October 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology: Regional Studies, Volume 19〈/p〉 〈p〉Author(s): José Bandeira Brasil, Eunice Maia de Andrade, Helba Araújo de Queiroz Palácio, Pedro Henrique Augusto Medeiros, Julio Cesar Neves dos Santos〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈h6〉Study region〈/h6〉 〈p〉Iguatu Experimental Basin, located in the semi-arid region of northeastern Brazil.〈/p〉 〈/div〉 〈div〉 〈h6〉Study focus〈/h6〉 〈p〉The aim of this study was to investigate the influence of rainfall characteristics on throughfall, stemflow and interception loss in a deciduous forest of a tropical semi-arid region, from a data series of eight consecutive years. The data were collected from 2010 to 2017, comprising a total of 225 events.〈/p〉 〈/div〉 〈div〉 〈h6〉New hydrological insights for the region〈/h6〉 〈p〉Among the variables used to characterize rainfall, the maximum 30-min intensity (〈em〉I30〈/em〉) best explained the interception losses, which is also well correlated to rainfall depth and event average intensity. The predominant events (67% of the total) are characterised by low rainfall depth, low 〈em〉I30〈/em〉 and higher interception loss (18% of the gross rainfall). In addition, there is a threshold between rainfall characteristics and the interception process: for rainfall and 〈em〉I30〈/em〉 lower than 20 mm and 15 mm/h respectively, and rainfall duration lower than 100 min, interception losses are usually higher than 30%, reaching up to 74%. For the remaining events, interception losses are mostly within the range of 10–20% of rainfall. The data and information on the interception process, presented in this study, helps the comprehension of the overall water balance in dry environments and improve the capacity for parameterization of hydrological models, contributing to a more efficient water and environmental management.〈/p〉 〈/div〉

Description: 〈p〉Publication date: 5 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Differential Equations, Volume 266, Issue 1〈/p〉 〈p〉Author(s): Yongki Lee〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We identify sub-thresholds for finite time shock formation in a class of non-local conservation law with concavity changing flux. From a class of non-local conservation laws, the Riccati-type ODE system that governs a solution's gradient is obtained. The changes in concavity of the flux function correspond to the sign changes in the leading coefficient functions of the ODE system. We identify the blow up condition of this structurally generalized Riccati-type ODE. The method is illustrated via the traffic flow models with nonlocal-concave-convex flux. The techniques and ideas developed in this paper is applicable to a large class of non-local conservation laws.〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Differential Equations, Volume 266, Issue 1〈/p〉 〈p〉Author(s): A.A. Kashchenko〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this paper, nonlocal dynamics of a system of two differential equations with a compactly supported nonlinearity and delay is studied. For some set of initial conditions asymptotics of solutions of considered system is constructed. By this asymptotics we build a special mapping. Dynamics of this mapping describes dynamics of initial system in general: it is proved that stable cycles of this mapping correspond to exponentially orbitally stable relaxation periodic solutions of initial system of delay differential equations. It is shown that amplitude, period of solutions of initial system, and number of coexisting stable solutions depend crucially on coupling parameter. Algorithm for constructing many coexisting stable solutions is described.〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Differential Equations, Volume 266, Issue 1〈/p〉 〈p〉Author(s): Barbara Niethammer, Alessia Nota, Sebastian Throm, Juan J.L. Velázquez〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this paper we consider the long-time asymptotics of a linear version of the Smoluchowski equation which describes the evolution of a tagged particle moving in a random distribution of fixed particles. The volumes 〈em〉v〈/em〉 of these particles are independently distributed according to a probability distribution which decays asymptotically as a power law 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si1.gif" overflow="scroll"〉〈msup〉〈mrow〉〈mi〉v〈/mi〉〈/mrow〉〈mrow〉〈mo〉−〈/mo〉〈mi〉σ〈/mi〉〈/mrow〉〈/msup〉〈/math〉. The validity of the equation has been rigorously proved in [22] taking as a starting point a particle model and for values of the exponent 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si2.gif" overflow="scroll"〉〈mi〉σ〈/mi〉〈mo〉〉〈/mo〉〈mn〉3〈/mn〉〈/math〉, but the model can be expected to be valid, on heuristic grounds, for 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si3.gif" overflow="scroll"〉〈mi〉σ〈/mi〉〈mo〉〉〈/mo〉〈mfrac〉〈mrow〉〈mn〉5〈/mn〉〈/mrow〉〈mrow〉〈mn〉3〈/mn〉〈/mrow〉〈/mfrac〉〈/math〉. The resulting equation is a non-local linear degenerate parabolic equation. The solutions of this equation display a rich structure of different asymptotic behaviors according to the different values of the exponent 〈em〉σ〈/em〉. Here we show that for 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si4.gif" overflow="scroll"〉〈mfrac〉〈mrow〉〈mn〉5〈/mn〉〈/mrow〉〈mrow〉〈mn〉3〈/mn〉〈/mrow〉〈/mfrac〉〈mo〉〈〈/mo〉〈mi〉σ〈/mi〉〈mo〉〈〈/mo〉〈mn〉2〈/mn〉〈/math〉 the linear Smoluchowski equation is well-posed and that there exists a unique self-similar profile which is asymptotically stable.〈/p〉〈/div〉