ALBERT

Description: On February 6, 2023, at 01 : 17 UTC, a M = 7 8 earthquake struck the southern area of Turkey near Gaziantep town and was followed by a second earthquake of M = 7 5 at 10 : 24 UTC with the epicenter in Elbistan city. Both events were associated with the Anatolian Fault System and have claimed over 50,000 victims, as reported by the Disaster and Emergency Management Authority, and caused serious damage in the regions of southern Turkey and northern Syria. Seismic waves related to strong Turkey earthquakes have been recorded both by seismic stations throughout the globe and on other devices such as the ground deformation (GNSS, strainmeters, or tiltmeters) networks. In this paper, we show and analyze the earthquake signals recorded by bore-hole tilt stations that monitor seismic and volcanic activities at Mt. Etna. Tilt stations showed very large variations, despite their distance from the epicenter (approximately 1950 km) with a period between 10 and 25 seconds. We compared tilt and seismic data for a co–located station evidencing a very similar waveform that highlight how tiltmeters respond to translational acceleration rather than ground tilt during a teleseism, suggesting that, for waves with this period, they may behave as horizontal seismometers. By using these signals, we evidence the different behaviors of two of the most used models of tiltmeters on volcanoes (Lily and Pinnacle) and how they are useful for instrument calibration.

Description: Published

Description: 9030495

Description: OSV3: Sviluppo di nuovi sistemi osservazionali e di analisi ad alta sensibilità

Description: JCR Journal

Description: Much of our understanding of Cenozoic climate is based on the record of δ18O measured in benthic foraminifera. However, this measurement reflects a combined signal of global temperature and sea level, thus preventing a clear understanding of the interactions and feedbacks of the climate system in causing global temperature change. Our new reconstruction of temperature change over the past 4.5 million years includes two phases of long-term cooling, with the second phase of accelerated cooling during the Middle Pleistocene Transition (1.5 to 0.9 million years ago) being accompanied by a transition from dominant 41,000-year low-amplitude periodicity to dominant 100,000-year high-amplitude periodicity. Changes in the rates of long-term cooling and variability are consistent with changes in the carbon cycle driven initially by geologic processes, followed by additional changes in the Southern Ocean carbon cycle. 〈/jats:p〉

Description: Marine heatwaves are increasing in frequency and intensity as climate change progresses, especially in the highly productive Arctic regions. Although their effects on primary producers will largely determine the impacts on ecosystem services, mechanistic understanding on phytoplankton responses to these extreme events is still very limited. We experimentally exposed Arctic phytoplankton assemblages to stable warming, as well as to repeated heatwaves, and measured temporally resolved productivity, physiology, and composition. Our results show that even extreme stable warming increases productivity, while the response to heatwaves depends on the specific scenario applied and is not predictable from stable warming responses. This appears to be largely due to the underestimated impact of the cool phase following a heatwave, which can be at least as important as the warm phase for the overall response. We show that physiological and compositional adjustments to both warm and cool phases drive overall phytoplankton productivity and need to be considered mechanistically to predict overall ecosystem impacts.

Description: 〈jats:p〉Extensive ice coverage largely prevents investigations of Antarctica’s unglaciated past. Knowledge about environmental and tectonic development before large-scale glaciation, however, is important for understanding the transition into the modern icehouse world. We report geochronological and sedimentological data from a drill core from the Amundsen Sea shelf, providing insights into tectonic and topographic conditions during the Eocene (~44 to 34 million years ago), shortly before major ice sheet buildup. Our findings reveal the Eocene as a transition period from >40 million years of relative tectonic quiescence toward reactivation of the West Antarctic Rift System, coinciding with incipient volcanism, rise of the Transantarctic Mountains, and renewed sedimentation under temperate climate conditions. The recovered sediments were deposited in a coastal-estuarine swamp environment at the outlet of a >1500-km-long transcontinental river system, draining from the rising Transantarctic Mountains into the Amundsen Sea. Much of West Antarctica hence lied above sea level, but low topographic relief combined with low elevation inhibited widespread ice sheet formation.〈/jats:p〉

Description: One of Earth’s most fundamental climate shifts – the greenhouse-icehouse transition 34 Ma ago – initiated Antarctic ice-sheet build-up, influencing global climate until today. However, the extent of the ice sheet during the Early Oligocene Glacial Maximum (~33.7–33.2 Ma) that immediately followed this transition, a critical knowledge gap for assessing feedbacks between permanently glaciated areas and early Cenozoic global climate reorganization, is uncertain. Here, we present shallow-marine drilling data constraining earliest Oligocene environmental conditions on West Antarctica’s Pacific margin – a key region for understanding Antarctic ice sheet-evolution. These data indicate a cool-temperate environment, with mild ocean and air temperatures preventing West Antarctic Ice Sheet formation. Climate-ice sheet modeling corroborates a highly asymmetric Antarctic ice sheet, thereby revealing its differential regional response to past and future climatic change.

Description: In this report, the European Scientific Advisory Board on Climate Change recommends a series of actions to put the EU on track towards climate neutrality. Based on an assessment of more than 80 indicators, the Advisory Board found that more efforts are needed across all sectors to achieve the EU climate objectives from 2030 to 2050, and particularly in buildings, transport, agriculture and forestry. The Advisory Board acknowledges the potential of the Fit for 55 policy package to speed up EU’s decarbonisation, but warns that additional measures are imperative if the EU is to achieve its climate neutrality objective by 2050 at the latest. With this in mind, the Advisory Board outlines 13 key recommendations for a more effective implementation and design of the EU climate policy framework. This will require action in the coming years, both to effectively implement recently agreed legislation and to start preparations for the post-2030 climate policy framework.

Description: Antarctic krill, crucial to the Southern Ocean ecosystem and a vital fisheries resource, is endangered by climate change. Identifying drivers of krill biomass is therefore essential for determining catch limits and designating protection zones. We present a modeling approach to pinpointing effects of sea surface temperature, ice cover, chlorophyll levels, climate indices, and intraspecific competition. Our study reveals that larval recruitment is driven by both competition among age classes and chlorophyll levels. In addition, while milder ice and temperature in spring and summer favor reproduction and early larval survival, both larvae and juveniles strongly benefit from heavier ice and colder temperatures in winter. We conclude that omitting top-down control of resources by krill is only acceptable for retrospective or single-year prognostic models that use field chlorophyll data but that incorporating intraspecific competition is essential for longer-term forecasts. Our findings can guide future krill modeling strategies, reinforcing the sustainability of this keystone species.

Description: Commission Decision of 25 February 2016 setting up a Scientific, Technical and Economic Committee for Fisheries, C(2016) 1084, OJ C 74, 26.2.2016, p. 4–10. The Commission may consult the group on any matter relating to marine and fisheries biology, fishing gear technology, fisheries economics, fisheries governance, ecosystem effects of fisheries, aquaculture or similar disciplines. This report deals with the monitoring of the performance of the Common Fisheries Policy.

Description: European Commission

Description: Published

Description: Refereed

Description: Commission Decision of 25 February 2016 setting up a Scientific, Technical and Economic Committee for Fisheries, C(2016) 1084, OJ C 74, 26.2.2016, p. 4–10. The Commission may consult the group on any matter relating to marine and fisheries biology, fishing gear technology, fisheries economics, fisheries governance, ecosystem effects of fisheries, aquaculture or similar disciplines. This report contains a review of Joint Recommendations submitted by Member States Regional Groups for the implementation of the Landing Obligation in 2024 and beyond.

Description: European Commission

Description: Published

Description: Refereed

Description: The JRC presented a brief review of the current STECF system in place to provide advice on Mediterranean fisheries management and data collection issues. JRC highlighted some structural risks and inefficiencies that currently exist. The review explored some examples of integrated actions that could reduce or mitigate such risks. Such actions as part of a long-term strategy would lead to a proactive advisory process as opposed to the current more reactive sequence of individual steps considered by STECF. STECF notes this initiative from the JRC and aims to revisit the topic in time for development of the next management plan stage, post 2025. On 21 February 2023, the Commission adopted the Fisheries and Ocean package consisting of four documents: the Communication on the functioning of the CFP, the Action Plan “Protecting and restoring marine ecosystems for sustainable and resilient fisheries”, the Energy transition initiative and the report on the functioning of the Common Market Organisation (CMO). The package brings together all different aspects of the EU’s policy on fisheries and the Ocean, looking at the future, and at how we can ensure that fisheries continue to grow in resilience and sustainability. With this package, the European Commission plans on launching a policy discussion with all institutions and stakeholders the EU’s policy on fisheries and the Ocean

Description: European Commission

Description: Published

Description: Refereed

Description: Commission Decision of 25 February 2016 setting up a Scientific, Technical and Economic Committee for Fisheries, C(2016) 1084, OJ C 74, 26.2.2016, p. 4–10. The Commission may consult the group on any matter relating to marine and fisheries biology, fishing gear technology, fisheries economics, fisheries governance, ecosystem effects of fisheries, aquaculture or similar disciplines. This report is the 10th of a suite of STECF EWG reports dedicated to the evaluation of the implementation of the Western Mediterranean Sea Multi-Annual management Plan (hereafter, MAP), following EWG reports 18-09, 18-13, 19-01, 19-14, 20-13, 21-01, 21- 13, 22-01 and 22-11. The group was requested to continue the development of socio-economic indicators to be used in the evaluation of management measures for the West Med MAP in both West Med management units (EMU1 and EMU 1) (TOR1). Two roadmaps were discussed, a short term approach and a long term approach which would consider the expansion of all the mixed-fisheries bio-economic models to both management units. As a first step, the group focused on the proposal of harmonizing the economic indicators across the models implemented (TOR2). The group was than requested to further develop the approach implemented during EWG 22-01 to identify persistence hotspots of the six target species of the West Med MAP using scientific survey data (MEDITS) in combination to commercial spatial data (VMS joined with logbooks), to test existing and additional closure areas (TOR 3). The group was also requested to revise Article 8 of the 2023 fishing opportunities for the West Med MAP (COUNCIL REGULATION (EU) 2023/195), which lists the compensation mechanisms that MSs can implement within the West Med MAP to obtain additional fishing days in 2023 (TOR 4). For TOR 1 a roadmap was discussed and proposed on how to organise the work on socio-economic assessments for the West Med MAP in 2023. The EWG suggests that here should be a three-step process: a scoping exercise (done with EWG 23- 01), a meeting with stakeholders in the middle of the year to discuss their perception of the socio-economic consequences of measures of the West Med MAP and the running of scenarios during EWG 23-11 with results from socio-economic assessments. The EWG notes that the modellers have only the five-day meeting in September to run scenarios. Therefore, it would be crucial for the success of the assessments that the 6 scenarios provided by DG Mare for the EWG 22-11 and with some adjustments for EWG 23-01 will not change for EWG 23-11. It is crucial because those scenarios are already implemented in the models and the implementation of new scenarios would take a lot of time. The EWG proposes to run a few additional scenarios with only one measures to separate impacts of certain measures from the six scenarios where a mixture of measures is included. This would hopefully allow to give an indication what additional efforts may be necessary to reach MSY (in 2025 but also beyond in case the objective is not reached by 2025) and when gains from the implementation of the West Med Plan could be expected. The EWG observes that modelers need to put in additional effort and resources to improve the models for an improved assessment of the West Med MAP. The models were not originally developed for the assessment of the West Med MAP and only cover parts of the area of the Western Mediterranean. Such an improvement of the models could also include work to provide longer-term socio-economic assessments of measures where modelers need to take additional assumptions into account. The EWG notes that it would be beneficial if modelers receive a basic list of assumptions for key economic variables before the EWG 23-11 meeting in September. In 2022, for example, the increased fuel costs were an important factor regarding the economic performance of the fleets. In 2023 fuel costs have decreased but there are other cost categories with a substantial increase. The EWG concludes that DG Mare should not change the 6 provided scenarios substantially before the EWG 23-11 meeting in September. This would allow the modelers to run the models during the meeting and provide the socio-economic results. The EWG concludes that STECF and DG Mare should further discuss how resources could be provided to modelers to improve the applied models. The EWG concludes that the chairs of EWG 23-01 and 23-11 will provide a list of assumptions for the implementation of the models regarding key variables for the socio-economic assessments (short- and long-term). For TOR 2 the EWG discussed what variables and indicators the applied models include and provide. From that discussion a list of indicators was developed for which modelers will be able to provide results in the EWG 23-11 report. The EWG concludes that a list of indicators is provided for which EWG 23-11 will present results in autumn 2023. For TOR 3 the EWG notes that new closure areas for 2023 were implemented only by Spain (EMU 1) (Orden APA/80/2023). All closures areas implemented under the West Med MAP are described to allow testing if their implementation would reduce the catches of juveniles and adults of the six target species of the MAP by 15-25%. The EWG notes that the methodology followed to prioritise, developing and updating closure areas based on their conservation value on the basis of existing closures, proposed closures from EWG 22-01 and new proposals developed by EWG 23-01 based on updated MEDISEH layers is similar to the one used during EWG 22- 01. Updated MEDISEH layers were used for priority species (ARA, MUT and HKE) in combination with old MEDISEH layers for other species and distribution maps of commercial effort from EWG 22-01. Calculation of the percentage of the trawlable GSA area closed to fishing is higher in EMU 1 than EMU 2, therefore the estimation of additional closure areas on top of the existing ones foccused on this management unit. Additional closure areas to test were based on persistence hotsposts from survey data and from areas of high effort in order to impact directly on the reduction of fishing mortality. The EWG notes that the exisiting and additional closures could be tested only in EMU 2 and GSA 7 as for GSA 1, 5 and 6 the extension of the spatially-explicit model ISIS-Fish is not complete yet and it is still limited to a single species (HKE). The EWG notes that closure areas in GSA 7 were tested with two different methods. A static method comparing effort distribution data before and after the closures implementation in 2020, and a dynamic method applying ISIS-Fish. The first method showed how the establishment of the spatio-temporal closure imposed a strong seasonal constraint to the fishing effort in the Gulf of Lions, and that the fishermen community responded quite well to the new rule, although vessels increased their fishing effort along the closure border, with a typical « fishing the line » pattern, especially in the fall. The second model showed that introducing an additional closure did not improve the rebuilding of the hake stock, while changing the closures from seasonal to permanent suggested the strongest effect. The EWG notes that in EMU 2 that temporal closures for the whole fleet reduce global effort while additional spatial closures increase effort towards coastal areas (depths 〈200m) specifically for fleet segments 〈18m. Fishing mortality instead is reduced for all species by the introducion of additional closures, specifically those targeting high effort areas, although Fmsy is reached only for ARS and DPS and for already underexploited stocks (MUT 10 and NEP). The EWG concludes that provided that the area in GSA 7 have been chosen according to juvenile hake catch, we can expect that, given the strong observed response of the fishermen community, the closure in GSA7 has the potential to positvely impact the hake recruitment in the long run. Still, two years of implementation remains a short time-scale to observe strong changes in a long- lived stock. More time, observations and analysis will be necessary in the future to further quantify the efficiency of these closures. The EWG concludes that no positive effects on the stocks biomasses are observed in EMU 2 indipendently of the scenarios applied. For TOR 4, the EWG notes that both definitions of “juveniles” and “spawners” are not clearly stated in the Regulation (95/2023) making a bit challenging the evaluation of the criterions. A similar consideration could be done for the term “catch reduction” which is never specified whether it should be considered in number or weight. The EWG could not fully understand if the compliance with the criterions in term of results achieved would be evaluated at some point in the process. The EWG reports that for point a) the literature suggests that the requested threshold of at least 25% of reduction in hake juveniles seems not achievable. For point b) only for Blue and red shrimps the introduction of a 50mm square mesh size seems to lead to the decrease of specimens below 25mm CL at least of 25%. However, for vessels targeting Blue and red shrimps in EMU2, this is a mixed fisheries targeting also Giant red shrimp and it is not applicable to have two different size thresholds for the two species. The EWG suggested that the criterion should be revised providing just one size threshold, ideally selecting the one proposed for blue and red shrimps. According to the IMPLEMED results the same conclusion of point a) can be shared with point c) when a grid of 20mm space bar is used. For point d) EWG cannot find any clear evidence or results which corroborate the fact that specific closures could lead to a reduction in juveniles and spawners at the level requested by the criterion. Point e) refers to an increase of the MCRS for hake (26cm TL) which if not linked with some additional technical measures should just lead to an increase of discards of hake and, likely, black market. For point f), the EWG agreed the temporal closures implemented by Spain and France under the West Med MAP are following the criterion. The EWG concludes that considering the available knowledge and the analysis done during the meeting only the requests based on point b) and point f) could be considered fully in compliance with what the criterion stated, for point d) there weren’t enough information to be fully evaluated if it is feasible or not while the others criterion seems to be not corroborated by the available literature.

Description: Published

Description: Refereed

Description: 〈jats:p〉Arctic Ocean gateway fluxes play a crucial role in linking the Arctic with the global ocean and affecting climate and marine ecosystems. We reviewed past studies on Arctic–Subarctic ocean linkages and examined their changes and driving mechanisms. Our review highlights that radical changes occurred in the inflows and outflows of the Arctic Ocean during the 2010s. Specifically, the Pacific inflow temperature in the Bering Strait and Atlantic inflow temperature in the Fram Strait hit record highs, while the Pacific inflow salinity in the Bering Strait and Arctic outflow salinity in the Davis and Fram straits hit record lows. Both the ocean heat convergence from lower latitudes to the Arctic and the hydrological cycle connecting the Arctic with Subarctic seas were stronger in 2000–2020 than in 1980–2000. CMIP6 models project a continuing increase in poleward ocean heat convergence in the 21st century, mainly due to warming of inflow waters. They also predict an increase in freshwater input to the Arctic Ocean, with the largest increase in freshwater export expected to occur in the Fram Strait due to both increased ocean volume export and decreased salinity. Fram Strait sea ice volume export hit a record low in the 2010s and is projected to continue to decrease along with Arctic sea ice decline. We quantitatively attribute the variability of the volume, heat, and freshwater transports in the Arctic gateways to forcing within and outside the Arctic based on dedicated numerical simulations and emphasize the importance of both origins in driving the variability.〈/jats:p〉

Description: The Timpe Fault System (TFS) represents the source of shallow earthquakes that strike numerous towns and villages on Mt. Etna’s eastern flank. In the last 40 years, three destructive seismic events reached (heavily damaging) in 1984 (October 25), 2002 (October 29), and 2018 (December 26). These events followed a few days after the occurrence of strong seismic swarms and the sudden acceleration of the eastern flank seaward. The damaging seismic events in 2002 and 2018 were associated with dike intrusions and eruptions of the volcano; however, no eruptive activity was observed at the time of the 1984 earthquakes. In this study, we investigate seismic parameters for the 1984 sequence, in order to interpret the seismicity in terms of volcanic activity. Parameters such as localization, cumulative seismic moment, and hourly occurrence frequency of the 1984 seismic swarm have been analysed and shown to have typical values of Mt. Etna’s intrusive seismic swarms. This suggests that the 1984 episode may have been an aborted intrusive magma episode that triggered similar processes (long and powerful intrusions with acceleration of the eastern flank movement and destructive earthquakes), as in 2002 and 2018. These three episodes suggest that an evaluation of some seismic parameters during future intrusive swarms may furnish indications of a possible reactivation of the TFS.

Description: Published

Description: 8565536

Description: 6V. Pericolosità vulcanica e contributi alla stima del rischio

Description: JCR Journal

Description: Commission Decision of 25 February 2016 setting up a Scientific, Technical and Economic Committee for Fisheries, C(2016) 1084, OJ C 74, 26.2.2016, p. 4–10. The Commission may consult the group on any matter relating to marine and fisheries biology, fishing gear technology, fisheries economics, fisheries governance, ecosystem effects of fisheries, aquaculture or similar disciplines This report documents the outcomes of STECF Expert Working Group 22-09: 2022 stock assessments of demersal stocks in the western Mediterranean Sea from the meeting held remotely from 5th to 11th September 2022. A total of 20 fish stocks considered and 18 were fully evaluated. Two stocks had prior advice from 2021 with catch advice for 2022 and 2023, and this is reiterated here. The EWG reports age based assessments, target Fs, with short term forecasts for 15 of the remaining 18 stocks, of these 15, 12 were also analysed for biomass reference points. Catch advice for three stocks was based on ICES category three evaluations of biomass indices. The content of the report gives the STECF terms of reference; the basis of the evaluations; assessments, reference point calculations; summaries of state of stock and advised catch or F based on either the MSY approach for assessed stocks and category 3 based advice for those without assessments. The report contains the full stock assessment reports for the 15 assessments, the exploration of assessments and category 3 evaluations for the remaining three stocks. The report also contains the STECF observations and conclusions on the assessment report. These conclusions come from the STECF Plenary meeting November 2022.

Description: European Union

Description: Published

Description: Refereed

Description: Dissolved iron (dFe) availability limits the uptake of atmospheric CO2 by the Southern Ocean (SO) biological pump. Hence, any change in bioavailable dFe in this region can directly influence climate. On the basis of Fe uptake experiments with Phaeocystis antarctica, we show that the range of dFe bioavailability in natural samples is wider (〈1 to ~200% compared to free inorganic Fe′) than previously thought, with higher bioavailability found near glacial sources. The degree of bioavailability varied regardless of in situ dFe concentration and depth, challenging the consensus that sole dFe concentrations can be used to predict Fe uptake in modeling studies. Further, our data suggest a disproportionately major role of biologically mediated ligands and encourage revisiting the role of humic substances in influencing marine Fe biogeochemical cycling in the SO. Last, we describe a linkage between in situ dFe bioavailability and isotopic signatures that, we anticipate, will stimulate future research.

Description: 〈jats:p〉Rapidly shrinking Arctic sea ice has had substantial impacts on the Earth system. Therefore, reliably estimating the Arctic sea-ice thickness (SIT) using a combination of available observations and numerical modeling is urgently needed. Here, for the first time, we assimilate the latest CryoSat-2 summer SIT data into a coupled ice-ocean model. In particular, an incremental analysis update scheme is implemented to overcome the discontinuity resulting from the combined assimilation of biweekly SIT and daily sea-ice concentration (SIC) data. Along with improved estimates of sea-ice volume, our SIT estimates corrected the overestimation of SIT produced by the reanalysis that assimilates only SIC in summer in areas where the sea ice is roughest and experiences strong deformation, e.g., around the Fram Strait and Greenland. This study suggests that the newly developed CryoSat-2 SIT product, when assimilated properly using our approach, has great potential for Arctic sea-ice simulation and prediction.〈/jats:p〉

Description: The marine-based West Antarctic Ice Sheet (WAIS) is considered vulnerable to irreversible collapse under future climate trajectories, and its tipping point may lie within the mitigated warming scenarios of 1.5° to 2°C of the United Nations Paris Agreement. Knowledge of ice loss during similarly warm past climates could resolve this uncertainty, including the Last Interglacial when global sea levels were 5 to 10 meters higher than today and global average temperatures were 0.5° to 1.5°C warmer than preindustrial levels. Using a panel of genome-wide, single-nucleotide polymorphisms of a circum-Antarctic octopus, we show persistent, historic signals of gene flow only possible with complete WAIS collapse. Our results provide the first empirical evidence that the tipping point of WAIS loss could be reached even under stringent climate mitigation scenarios.

Description: Paleoceanographic reconstructions show that the strength of North Atlantic currents decreased during the Little Ice Age. In contrast, the role of ocean circulation in climate regulation during earlier historical epochs of the Common Era (C.E.) remains unclear. Here, we reconstruct sea surface temperature (SST) and salinity in the Caribbean Basin for the past 1700 years using the isotopic and elemental composition of planktic foraminifera tests. Centennial-scale SST and salinity variations in the Caribbean co-occur with (hydro)climate changes in the Northern Hemisphere and are linked to a North Atlantic SST forcing. Cold phases around 600, 800, and 1400 to 1600 C.E. are characterized by Caribbean salinification and Gulf of Mexico freshening that implies reductions in the strength of North Atlantic surface circulation. We suggest that the associated changes in the meridional salt advection contributed to the historical climate variability of the C.E.

Description: Commission Decision of 25 February 2016 setting up a Scientific, Technical and Economic Committee for Fisheries, C(2016) 1084, OJ C 74, 26.2.2016, p. 4–10. The Commission may consult the group on any matter relating to marine and fisheries biology, fishing gear technology, fisheries economics, fisheries governance, ecosystem effects of fisheries, aquaculture or similar disciplines This report documents the outcomes of STECF Expert Working Group 23-09: 2023 stock assessments of demersal stocks in the Western Mediterranean Sea from the meeting held in hybrid mode from 4th to 10th September 2023. A total of 20 fish stocks considered. Nine stocks were evaluated by means of a statistical catch at age (SCAA) model (a4a). Due to the lack of survey information in 2022, five stocks were evaluated through a catch weight projection and short-term forecast. The methodological approach is described in the last part of this Executive Summary, and in the Report. In 2022, index- based advice was given for three stocks (ARA8-9-10-11 and NEP11 on two years basis while for MUT 10 just for one year), and they were re-evaluated by EWG 23-09. The advice for ARA8-9-10-11 and NEP11 have been confirmed while for MUT 10 the missing index information led the group to consider downgrading the advice from an index-based one to a catch only advice approach (ICES Category 5). Two stocks for which the index-based advice provided in 2021 (2 years advice) have been evaluated again looking for a plausible fully analytical assessment. None of the model setting tried was able to provide acceptable results, therefore a biomass index-based advice is given again. The content of the report gives the STECF terms of reference; the basis of the evaluations; assessments, reference point calculations; summaries of state of stock and advised catch or F based on either the MSY approach for assessed stocks and category 3 and 5 based advice for those without assessments. The report contains the full stock assessment reports, the exploration of assessments and category 3 and 5 evaluations for the remaining stocks. The report also contains the STECF observations and conclusions on the assessment report. These conclusions come from the STECF mini plenary meeting October 2023.

Description: European Commission

Description: Published

Description: Refereed

Description: 〈jats:p〉Comprehensive sampling of natural genetic diversity with metagenomics enables highly resolved insights into the interplay between ecology and evolution. However, resolving adaptive, neutral, or purifying processes of evolution from intrapopulation genomic variation remains a challenge, partly due to the sole reliance on gene sequences to interpret variants. Here, we describe an approach to analyze genetic variation in the context of predicted protein structures and apply it to a marine microbial population within the SAR11 subclade 1a.3.V, which dominates low-latitude surface oceans. Our analyses reveal a tight association between genetic variation and protein structure. In a central gene in nitrogen metabolism, we observe decreased occurrence of nonsynonymous variants from ligand-binding sites as a function of nitrate concentrations, revealing genetic targets of distinct evolutionary pressures maintained by nutrient availability. Our work yields insights into the governing principles of evolution and enables structure-aware investigations of microbial population genetics.〈/jats:p〉

Description: The European Climate Law requires the EU to adopt a 2040 climate target, taking into account the advice from the European Scientific Advisory Board on Climate Change. The Advisory Board recommends keeping the EU’s cumulative greenhouse gas emissions below 11-14 Gt CO2e between 2030 and 2050, and reducing EU greenhouse gas emissions by 90-95 % by 2040, relative to 1990. A fair contribution to climate change mitigation requires ambitious reductions in domestic emissions, complemented by measures outside the EU. The EU 2030 target of at least a 55% reduction in greenhouse gas emissions compared to 1990 enables it to reach the recommended 2040 target range and climate neutrality by 2050. The recommended 2040 emission reductions can be achieved through several pathways. Despite their differences, they show a high degree of convergence on a range of issues.

Description: Commission Decision of 25 February 2016 setting up a Scientific, Technical and Economic Committee for Fisheries, C(2016) 1084, OJ C 74, 26.2.2016, p. 4–10. The Commission may consult the group on any matter relating to marine and fisheries biology, fishing gear technology, fisheries economics, fisheries governance, ecosystem effects of fisheries, aquaculture or similar disciplines. . This report is from STECF Expert Working Group 19-16: 2019 stock assessments of demersal stocks in the Adriatic Sea from the meeting in Rome Italy from 14th to 20th October 2019. A total of seven fish species were evaluated for GSA 17, 18 and 19. The EWG reports age based assessments and short term forecasts for all seven stocks. The content of the report gives the STECF terms of reference, the basis of the evaluations and advice, summaries of state of stock and advised based on either the MSY approach for assessed. The report contains the full stock assessment reports for the seven assessments, and three exploratory assessments for deep-water rose shrimp for each GSA separately. Advice for deep-water rose shrimp is based on the combined stock, the report also contains the STECF observations and conclusions on the assessment report. These conclusions come from the STECF Plenary meeting November 2019.

Description: European Commission

Description: European Union, Joint Research Centre

Description: Published

Description: Refereed

Description: The working group was held in remotely, from 7th to 18th Sept 2020. The meeting was attended by 21 experts in total, including three STECF members and four JRC experts. The EWG had two observers who attended part time. The objective of the Mediterranean Methodology EWG 20-09 was to carry out assessments and provide draft advice for stocks identified in the ToR supplied by STECF. An initial plenary session commenced at 09:30 on the first day. The ToRs were discussed and examined in detail. Stocks were allocated to participants based on expertise. An ftp repository was created ad-hoc to share documents, data and scripts and prepare the report. The stock assessments were evaluated by the by all participants. Most of the work was concluded by Tuesday 15 Sept, after 7 full days of work, and some additional work at the weekend. However, two stocks remained to be completed, this extra work was carried out largely by two participant with support from small subgroups. The WG met for a final session on Friday 18 Sept. to conclude the work on one stock. Following extensive trials the last stock could not be assessed with an analytic age based assessment and advice was based on the MEDITS index. Over the first 7 working days plenary sessions were held each day to monitor progress and share results. The overall conclusions for each stock were discussed and finalized in plenary on the Tuesday, though the last assessment was finalised on the following Friday, the last day of the meeting.

Description: European Commission

Description: European Union, Joint Research Centre

Description: Published

Description: Refereed

Description: Commission Decision of 25 February 2016 setting up a Scientific, Technical and Economic Committee for Fisheries, C(2016) 1084, OJ C 74, 26.2.2016, p. 4–10. The Commission may consult the group on any matter relating to marine and fisheries biology, fishing gear technology, fisheries economics, fisheries governance, ecosystem effects of fisheries, aquaculture or similar disciplines. Within a management strategy evaluation harvest control rules were tuned and robustness tested for the anchovy and sardine stocks in the Adriatic Sea. This investigation was done in support of GFCM and a continuation of the preliminary report (EWG 21-adhoc-02). For the sardine stock no meaningful MSE could be conducted. For the anchovy stock two HCRs were identified to be achieving the management targets and being robust.

Description: Published

Description: Non Refereed

Description: Commission Decision of 25 February 2016 setting up a Scientific, Technical and Economic Committee for Fisheries, C(2016) 1084, OJ C 74, 26.2.2016, p. 4–10. The Commission may consult the group on any matter relating to marine and fisheries biology, fishing gear technology, fisheries economics, fisheries governance, ecosystem effects of fisheries, aquaculture or similar disciplines. This report is the ninth of a suite of STECF EWG reports dedicated to the evaluation of the implementation of the Western Mediterranean Sea Multi-Annual management Plan (hereafter, MAP), following EWG reports 18-09, 18-13, 19-01, 19-14, 20-13, 21-01, 21- 13, 22-01. The group was requested to implement mixed fisheries bio-economic models to run a number of scenarios up to 2030 with varying parameters, to evaluate a fishing effort reductions for trawlers, longliners and netters in association to vessel number reductions for trawlers, increase in mesh size for trawlers, existing closure areas and catch limits for deep water shrimps (ARA and ARS) through five scenarios and draft a mixed fisheries advice. For all mixed fisheries models applied during the EWG (TOR 3), the data from the DCF official data calls and from the western Mediterranean stock assessments, were updated using data from EWG 22-09 (Western Mediterranean stock assessments) and EWG 22-10 (FDI datacall). The same set of updated data were also used to answer TOR 1 and TOR 2. The exploration of effort data time series (TOR 1) highlighted that in GSA7 the French OTB fleet 〉18m showed a decrease in fishing days counteracted by an increase of the corresponding fleet segments of French OTT which could be potentially due to a shift in gear use, although experts did not suggest specific causes that would drive this shift. The comparison of fishing days for trawlers (OTB, OTM, OTT, PTB, PTM and TBB as per EU regulation 2019/2236) declared in the FDI official datacall and reported in the 2020 and 2021 regulations were reported this year as well. Discrepancies were found also between 2021 data and the 2021 regulation (as per 2020) with the values reported in the regulation being always higher (for all countries but not for all fleet segments) than the values declared in the FDI datacall. Results suggest that effort is decreasing faster than the regulation for most fleet segments and that the reference period 2015-2017 might not be representative anymore of the effort dynamics of the last few years. For Spain and Italy reductions by 2021 are suggested to be higher than the expected reduction by 2022, while this does not happen for France. From the data quality checks very minor issues were highlighted and there was no reporting in the DTMT of these issues. EWG 22-11 would like to ask for clarifications to MSs concerning the association of gear type with the upper level of aggregation fishing technique as it was observed that odd matching were found which could undermine the calculation of fishing days in the comparisons with the yearly regulations. Specifically the gear OTB was often found under the PGP fishing technique and experts present at the EWG were not able to explain this match. The estimated F by gear and GSA (TOR2) allowed updating the analysis of the linear relationship between F and E. As in previous years a linear relationship consistent across GSAs and stocks was not found. The HKE, MUT and ARA stocks showed a linear relationship with OTB in some cases. For HKE 1567 the relationship did not hold once observed by GSA (although this could be a modelling artefact from the assessment model) or in EMU 2. MUT showed a linear relationship in GSA 6 and 7 with OTB and OTT (but results for GSA 7 should be taken with caution as there is a very strong variation in F for a lower variation of effort). ARA in EMU 1 by GSA (and on the overall stock 6-7) showed a linear relationship with OTB. No relationship was found for gears as LLS, GTR (except for MUT in 9) or GNS, neither for the stocks of DPS or ARS. EWG 22-11 suggests that running the analysis at metier level would give more meaningful results, although it should be noted that the metier is a very unstable resolution of fisheries, therefore difficult to define as data sources. To the methodological section of models (Section 5) two subsections were added, one on the models behavior during mid and long term projections and one on the relationship between biomass increase and economic gain. All models at the moment are suggested to be used for mid-term projections but not for long-term projections as the population dynamics are led either by stock recruitment relationships (BEMTOOL), which are not robust at the moment due to the nature of the data or led by recruitment stochasticity (IAM, ISIS-Fish and SMART), based on a random resampling of the time series but not accounting for potential environmental effects. This year for EMU 1 new analytical assessments were available to EWG 22-11 such as ARA 5, DPS 1 and DPS 5-6-7. In EMU 2, instead, 2 stocks were lost as it was not possible to have an updated analytical assessment due to data issues for MUT 10 and ARA 8-9-10-11. As ARA is one of the stocks with a catch limit defined by the EU Regulation 2022/110, the limitations due to the lack of assessment for this species when running the models in EWG 22-11, should be noted. Based on the final draft report from EWG 22-09, stock assessment of Western Mediterranean, which will be presented to STECF in November 2022, but has not yet been endorsed by STECF, the EWG observed that in 2020, 94% and, in 2021, 79% of the stocks were not at MSY. In 2022, the EWG shows that 73% of the stocks are not at MSY and 53% remain severely overfished. Some of the stocks could be already responding positively to the MAP measures, although the MAP has been implemented only since 2020 and the data available are only up to 2021. 9 out of 14 assessed stocks have decreasing fishing mortality, however, there are 4 stocks still behind transition to MSY of which two have declining biomass and increasing fishing mortality. Some stocks need particular attention for their low biomass level. EWG 22-09 identified as below the biomass reference point (Blim): Hake in GSAs 1-5-6-7, Hake in GSAs 8-9-10-11 and Blue and red shrimp in GSAs 1-2. In addition, five stocks are also below Bpa. Despite progress towards MSY, high levels of overfishing remains in particular for hake and deep-water shrimps. Models results (Section 6) showed that for EMU 1 (result only from IAM) none of the proposed scenarios (5 scenarios + status quo) achieved the objective of reaching FMSY by 2025. Red mullet in GSA 6 (MUT6) never reaches its Fmsy range during the simulation period (2022-2030) under any scenario, and hake in GSA 1-5-6-7 (HKE1567) is still above Fmsy in 2025. The other stock that is slightly behind the objectives is red mullet in GSA 1 (MUT1) with all scenarios. However, the other stocks (ARA12, ARA5, ARA67, NEP6, MUT7, DPS1 and DPS567) reach their FMSY range in 2025 with scenarios A to D. Only with the status quo scenario (scenario F) the FMSY range is not reached in 2025 for some of those stocks. Globally, all scenarios foresee some important negative economic impact for French and Spanish trawlers in the short and medium term with a decrease in their Gross Value Added. Even with scenario F (i.e. status quo), French trawler GVA is negative from 2022. This is due to the fuel price used in the simulation in 2022 and beyond from AER 2022 projections, where prices increased a lot compared to their initial values. Due to time constraints, it was not possible to have results from the ISIS-Fish model for EMU 1. For EMU 2 the setting of a maximum catch limit on ARA and ARS allows to approach FMSY for ARS, but not for HKE, even when in combination with other measures such as reduction of fishing days and number of vessels and change in selectivity. For ARS 8-9-10-11, NEP 9 and MUT 9 all scenarios implemented allow to reach FMSY in 2025 except for the status quo scenario (F). ARS, ARA and NEP stocks would benefit of all the scenarios, due to the re-allocation of the effort from the deep-water metier (OTB_DWS and OTB_DES) to the demersal (OTB_DES). This reallocation produces an increase in the fishing pressure on demersal fishing grounds, contributing to partly reduce the underutilization of red mullet in GSA 10, red mullet in GSA 9 and Norway lobster in GSA 9, but also increasing the F of hake. The total revenues and gross value added for the overall fleet are predicted to slightly increase with respect to the lowest values of the time series reached in 2020-2021. For scenarios A, B and D total revenues across all fleets will decrease compared to the SQ scenario (F), remaining above the recent values. A similar pattern is observed for gross value added. Simulations on fuel price increase of 120% (of the average fuel price in 2022) in 2023 onwards in EMU 1 showed an exacerbation on the GVA of fleet segments that already suffered from the management implementation. It should be highlighted that already with the "fuel option 1" (with fuel price in 2022 and onwards from AER projections), the economic performances are already negative, especially for French fleets, as the fuel price has strongly increased compared to 2021. Estimations of GVA in 2022, when effort reductions are still quite limited, are already negative suggesting that the negative GVAs are mainly due to the 2022 fuel price peak. In EMU 2 as well the main effect is to observe a lower GVA; specifically, the difference between the best performing scenario, that is B, and the status quo (F) is smaller. Here as well, the increase in fuel costs impacts more importantly on the GVA, compared to the decrease in fixed costs imposed by the effort limitations. For the application of the bio-economic models for the assessment of the development regarding the implementation of the West Med MAP it was decided to follow the methodology of the AER and, therefore, subsidies are not included in the calculations for income. The financial situation which the bio-economic models present for the year 2022 and beyond depend a lot on the assumptions regarding the development of fuel prices but include no mitigation measures for the fishing companies (like de minimis payments to cover parts of the increase in fuel costs 2022). Therefore, the modelling results show a lower level of gross value added compared to the real situation of the fishing companies. EWG 22-11 suggests that from an economic standpoint, it would make sense to conduct a detailed impact assessment (IA) for the further implementation of the West Med MAP. With such an assessment it would be possible to calculate possible scenarios (including possible mitigation and adaptation measures) regarding the implementation of effort reduction and the possible economic performance of the fishing fleets. The EU MSs affected by the management plan could then discuss possible mitigation and adaptation measures for the fishing sector. As such an IA is not requested by the West Med MAP it would have not follow the usual procedure within DG Mare and can be limited to assessments within the STECF context. EWG 22-11 concludes that the EWG chair and the STECF bureau should discuss with DG MARE how far such an impact assessment would be possible for the next EWG meeting in March 2023. Concerning economic indicators (Section 7), EWG 22-11 suggests that all the different bio- economic modules should report the same economic indicators and specific reference points should be defined in order to evaluate the economic results of the different simulated scenarios in a consistent way. The selected economic indicators should be harmonized with the ones applied by STECF for the assessment of the economic performance of the fleet (AER) and the “balance” indicators. Also, in the STECF report 18-15 (STECF 2018) indicators are proposed which could be possibly applied. Additionally EWG 22-11 highlights that there are no indicators on sociological characteristics in the bio-economic models so far. Some of the models give “social” indicators, but in general these are closely related to the economic ones (gross value added, crew share, employment) and they do not actually produce detailed results on the social impact of fisheries policies. Additional sections (Section 7) were added to review available information on technological creep in the western Mediterranean in the last ten years, but no information seems to be available now to account for this parameter within the models. A new section was dedicated to the development of a standardized ad hoc datacall for VMS and logbook data for MSs involved in the West Med MAP. The aim is to ease communication with MSs on the submission of these data and obtain a standardized format for all MSs that would fasten the work of experts in future EWGs. Due to time constraints, the two spatial modeling groups (SMART and ISIS-Fish) could not fulfill the scenarios requested in the TORs. The parameterization of such models is complex and time consuming, therefore to be able to respond to all TORs EWG 22-11 suggested that it would be very helpful to have scenarios at list a month before the beginning of the working group as it was done for EWG 22-01. Finally, in order to ease the work of EWGs concerned with the evaluation of effort and catch limit regime in the Western Mediterranean, catch at age matrices, F at age matrices and LFDs by GSA and gear for HKE and MUT stocks should be prepared in advance of the EWGs. This work could be held either during the western Mediterranean stock assessment EWG (to be evaluated with the chair of the EWG) or by a short ad hoc contract.

Description: European Union

Description: Published

Description: Refereed

Description: Commission Decision of 25 February 2016 setting up a Scientific, Technical and Economic Committee for Fisheries, C(2016) 1084, OJ C 74, 26.2.2016, p. 4–10. The Commission may consult the group on any matter relating to marine and fisheries biology, fishing gear technology, fisheries economics, fisheries governance, ecosystem effects of fisheries, aquaculture or similar disciplines. This report is the eighth of a suite of STECF EWG reports dedicated to the evaluation of the implementation of the Western Mediterranean Sea Multi-Annual management Plan (hereafter, MAP), following EWG reports 18-09, 18-13, 19-01, 19-14, 20-13, 21-01 and 21-13. The group was requested to implement mixed fisheries bio-economic models to run a number of scenarios up to 2025 with varying parameters and up to 2030 with fixed parameters, to evaluate existing closure areas implemented since 2020 and 2022, maximum catch limits (MCLs) implemented since 2022 and draft a mixed fisheries advice. For all mixed fisheries models applied during the EWG, the data from the DCF official data calls and from the western Mediterranean stock assessments, were the same as the ones used during STECF EWG 21-13, as there were no updates since 2021. The non-spatially explicit mixed fisheries models, IAM (for EMU 1) and BEMTOOL (for EMU 2), focused on the scenarios evaluating MCLs on ARA, ARS and HKE. Reference MCLs for ARA and ARS where obtained from the Regulation EU 2022/110 and from STECF EWG 21-11, while for HKE were obtained solely from EWG 21-11. IAM was updated to differentiate between a coastal and a deep-water trawling within the Spanish fleet segments, as France does not have a deep-water fishery at present. As the model timescale has a yearly resolution, it was not possible to estimate the effect of a monthly MCL. The scenarios considered had a MCL for HKE, one for ARA, and one for both HKE and ARA. These scenarios were run for a decreasing MCL through time (forward scenario: aims at reaching catch at Fmsy by 2025) and an increasing MCL through time (inverse scenario: starting value is catch at Fmsy) accounting for the distribution of stocks by GSA, for a total of 10 scenarios alternative to the baseline. None of the scenarios allowed reaching Fmsy for all six species targeted by the MAP, except when applying a MCL on both ARA and HKE, simultaneously. The results for the HKE stock should be taken with caution as the MCL was applied only to trawlers in these scenarios, but this species can generally be targeted also by longliners and gillnetters. The economic consequences of scenarios accounting for a MCL on HKE, or both ARA and HKE, lead to a massive drop of GVA for the Spanish and French trawling fleets, while economic advantages are observed for longliners and gillnetters. BEMTOOL was updated and refined to consider the different types of fishing activity exerted by each fleet segment at metier level. The model timescale is set at a monthly resolution, so it was possible to run scenarios accounting for a monthly MCL (monthly flexibility was not considered). Only scenarios accounting for a MCL either for ARA or ARS where run, but never in combination (ARA+ARS), nor considering a MCL on HKE, for a total of eight scenarios: forward scenario, inverse scenario, monthly forward scenario, monthly inverse scenario, once with an MCL on ARA and once with an MCL on ARS. Implementing a MCL on the deep-water fisheries suggested an improvement for all stocks except for HKE. ARA and ARS would improve thanks to the control of the MCL, while MUT, DPS and NEP would stay within the upper and lower limits of Fmsy, despite the reallocation of fishing effort from deep to coastal fisheries. The implementation of a reverse MCL did not show a recovery of the stocks. Moreover, a MCL split by month seems to have a lower impact on the catches of ARA and ARS in the short term. The GVA shows an increase for the passive gears fleets (i.e., gillnetters and longliners) and a strong decrease for all trawling fleets in the first two years, with a stable trend over the following years. The spatially explicit mixed fisheries model ISIS-Fish also ran scenarios accounting for MCLs, but only for HKE in GSA 7, implementing a forward, an inverse and a monthly MCL for a total of four scenarios. The forward scenario led to fishing mortalities below Fmsy in 2025 because the value defined for MCL did not account for biomass rebuilding. On the other hand, the fishing mortality achieved using the HCR in the inverse scenario, never fell below Fmsy, because of the unrestricted catches of netters and long-liners. In terms of revenues, both MCL paths led to strong decreases for trawlers. The spatially explicit mixed fisheries models, ISIS-Fish (GSA 7) and SMART (EMU 2), focused on the evaluation of closure areas: existing closure areas, existing closure areas which were seasonal to become permanent, existing closure areas extended to all fishing gears, additional closure areas (only EMU 2), expansion of closure areas by 50% (only EMU 2) and expansion of closure areas by 100% (only EMU 2). ISIS-Fish was applied only for HKE in GSA 7 being the first time this model was used within this working group. The extension of closure areas to all fishing gears (passive gears on top of trawlers) in GSA 7 did not show any improvement, while shifting from a seasonal to a permanent closure showed a decrease in F and an increase in SSB. A decrease of catches of juvenile hake of 20% was observed both with seasonal and permanent closures. Catches of adults increased due to recovery of the stock and considering the low level of initial catches. It should be noted that revenues increased for passive gears but decreased for trawlers. SMART was updated, increasing the spatial resolution of the spatial grid of the model, to be in line with outputs of the ad-hoc contracts preceding the EWG and with ISIS-Fish. None of the scenarios considered for EMU 2 evaluating spatial closures allowed to reach Fmsy by 2025, except for MUT in 10 and NEP in 9 which remains underutilized. SSB shows, nevertheless, an increase across years. None of the scenarios allowed to reduce catches by 20% for all species. All scenarios are associated with a sharp decrease in revenues; spatial closures not widened or seasonal would involve lower decrease of the profits than widened and permanent closures. Loss of profits is more evident for VL12-18 and VL18-24, although the loss is evident for all fleet segments. During EWG 22-01 no explicit comparison between the implementation of an effort regime and a MCL regime was run. The group advices to do so accounting for the limitations encountered in the implementation of MCLs during EWG 22-01. It should be noted that the reduction of GVA is estimated in the short term (up to 2025), but further tests should be done to estimate the trend of GVAs in the mid- and long-term. It is highlighted that given the large number of other species exploited beyond the key ones included in the management plan and in the simulation models, the actual socio-economic impact of the plan remains uncertain. Also, the economic results are presented considering a constant number of vessels, and would differ if the number of vessels is reduced. Additionally, it is difficult to evaluate the socio-economic impact of the MAP on the fleets as at present no socio-economic reference points are used to compare the results against those.

Description: European Union

Description: Submitted

Description: Non Refereed

Description: 〈jats:p〉 Next week, the Convention on the Conservation of Antarctic Marine Living Resources (CCAMLR) convenes in Hobart, Tasmania, to examine the state of marine life in the Southern Ocean. As part of the Antarctic Treaty System, this convention entered into force in 1982, and its focus on the region’s environmental integrity has never been more important, given the increasing effects of climate change and commercial fishing. An important focus over the past 40 years has been Antarctic krill, 〈jats:italic〉Euphausia superba〈/jats:italic〉 (hereafter krill), a keystone species that helps to hold this marine ecosystem together. Climate and fishing stresses should prompt the CCAMLR to address whether management of krill fishing is at a level that protects the Southern Ocean from losing its overall balance of marine life and the oceanic processes that regulate global climate. 〈/jats:p〉

Description: Commission Decision of 25 February 2016 setting up a Scientific, Technical and Economic Committee for Fisheries, C(2016) 1084, OJ C 74, 26.2.2016, p. 4–10. The Commission may consult the group on any matter relating to marine and fisheries biology, fishing gear technology, fisheries economics, fisheries governance, ecosystem effects of fisheries, aquaculture or similar disciplines. This report documents the outcomes of STECF Expert Working Group 22-16: 2022 stock assessments of demersal stocks in the Adtiat ic, Ionian and Aegean Seas from the meeting held in Rome from 17th to 23th October 2022. A total of 16 fish stocks were considered and 15 were fully evaluated. The EWG reports age based assessments, target Fs, with short term forecasts for 9 stocks of the remaining 6 stocks, four of these do not have short term forecasts as he assessments are not suitable, and one is given ICES category 3 advice. The content of the report gives the STECF terms of reference; the basis of the evaluations; assessments, summaries of state of stock and advised catch or F based on either the MSY approach for assessed stocks and category 3 based advice for those without assessments. The report contains the full stock assessment reports for the 14 assessments, the exploration of assessments and category 3 evaluations for the remaining stock. The report also contains the STECF observations and conclusions on the assessment report. These conclusions come from the STECF Plenary meeting November 2022.

Description: European Union

Description: Published

Description: Refereed

Description: Climate change poses multiple threats to human health and well-being in Europe. Extreme weather events, such as devastating floods, extensive wildfires or intense and long‑lasting heatwaves, that are more likely and more severe due to the changing climate have become part of our reality in recent years. The greatest direct climate-related threat to human health in Europe is heat, and the large number of excess deaths attributable to extremely high temperatures and prolonged heatwaves during the summer of 2022 is a case in point. Despite high average living standards, Europe's ageing society and prevalence of chronic diseases make its population particularly vulnerable to heat. The exposure of vulnerable groups to heat is increasing, driven not only by more frequent and intense heatwaves but also by ongoing urbanisation and the associated urban heat island effect, the fact that buildings and cities in most of Europe have not been constructed to protect people from high temperatures, or outdated work practices that ignore the dangers of heat exposure to human health. Vulnerable socio-economic groups are particularly affected by heat. This high vulnerability, combined with the projected substantial global warming, creates a dire picture of a future with growing numbers of heat-related deaths and ailments, as well as reduced labour productivity, affecting well‑being and prosperity across Europe. Climate-sensitive infectious diseases are another type of emerging threat discussed in this report. The increasing suitability of the climate for various pathogens or their vectors may translate into higher likelihood of disease transmission in larger parts of Europe. The arrival of travellers and goods into Europe from regions where dengue or malaria is endemic, combined with the increasing suitability of climate conditions for the mosquitoes that carry those diseases becoming permanent in parts of Europe, increases the probability of disease outbreaks.

Description: This is the fourth collection of reports of EFSA’s EU-FORA Fellowship Programme. EU-FORA started in 2016 as part of EFSA’s efforts to support the development of next generations of Europe’s food risk assessors. Five years later, it continues to empower food safety professionals, ensuring an interconnected community of experts, while stimulating the involvement of Member States in risk assessment work and building a common EU risk assessment culture.

Description: Providing evidence-based and scientifically robust risk assessments, as foreseen under Article 5 of the Regulation (EU) 1143/2014 on the prevention and management of the introduction and spread of invasive alien species (IAS), is one step in the process of developing the list of IAS of Union concern. The aim of the current study is to develop such risk assessments alongside evidence on management measures and their implementation cost and cost-effectiveness to help inform policies and prioritise actions. This study includes eight new risk assessments and associated management annexes, for the following species: Acacia mearnsii (Black wattle), Brachyponera chinensis (Asian needle ant), Cherax quadricarinatus (Australian red claw crayfish), Cipangopaludina chinensis (Chinese mystery snail), Misgurnus bipartitus (Northern oriental weatherfish), Myiopsitta monachus (Monk parakeet), Tradescantia fluminensis (Wandering jew), and Zostera japonica (Japanese eelgrass). This study further includes ten risk assessments from previous contracts, revised according to the comments from the Scientific Forum and other stakeholders, concerning the following species: Acridotheres cristatellus (Crested myna), Bipalium kewense (Hammerhead flatworm), Cervus nippon (Sika deer), Cherax destructor (Common yabby), Delairea odorata (Cape ivy), Marisa cornuarietis (Colombian ramshorn apple snail), Mulinia lateralis (Dwarf surf clam), Obama nungara (Nungara-Flatworm), Platydemus manokwari (New Guinea flatworm) and Pycnonotus jocosus (Red-whiskered bulbul).

Description: This study reviews the status of Marine Biodiversity Monitoring in the European Commission tendered the study “Marine Biodiversity Modelling” [RTD/2021/MV/10] to pursue the identification and characterization of a subset of candidate biodiversity models that could contribute to the implementation of the European Digital Twin of the Ocean (EU DTO). The EU DTO will be an operational infrastructure for digital ocean services that aims to support decision-making capabilities by authorities to implement EU policies like the Marine Strategy Framework Directive (MSFD) but also by citizens and businesses operating at sea. Specific objectives of the project were: 1. Conduct a horizon scan to identify and map available modelling approaches used to hindcast, nowcast; 2. Develop a comprehensive catalogue to classify available modelling approaches according to their characteristics; 3. Propose a subset of the most meaningful models among major model typologies; 4. Assess whether these models can be used in the implementation of the Digital Twin Ocean and can improve the decision-making capacity under the MFSD.

Description: The purpose of this report is to examine the current situation, risks and responses to the recreational use of nitrous oxide in Europe. To support this, the report also provides a state-of-the-art review of the chemistry, pharmacology and toxicology of the gas. It is intended for policymakers and practitioners.

Description: Forward looking analyses are needed in order to anticipate which policy/management options can deliver the very ambitious objectives of the Zero Pollution (ZP) action plan. Integrated and sophisticated numerical modelling tools are useful to generate future scenarios and ‘what if’ analysis as they allow the virtual manipulation of the anthropogenic pressures on ecological systems. JRC has been developing an integrated modelling framework covering the inland and marine waters of the EU, the Marine Modelling Framework (MMF) that follows the principle of the Digital Twins (DT) and that allow to test the impacts of diverse management strategies on the status of freshwater and marine ecosystems through the EU. In the present report, the JRC-DT for water and marine ecosystems is used to test how different policy options can help achieve some of the ZP objectives. From the six top ambitions of the ZP action plan, two are particularly relevant for the water/marine environments. First, the ZP action plan states that it aims at ‘improving water quality by reducing waste’ and in particular, it mentions the (reduction of) ‘plastic litter at sea (by 50%)’. The second relevant ambition refers to ‘improving soil quality by reducing nutrient losses and chemical pesticides’ use by 50%’, which does not only impact soil quality but also the receiving waters (rivers, lakes and seas).

Description: Commission Decision of 25 February 2016 setting up a Scientific, Technical and Economic Committee for Fisheries, C(2016) 1084, OJ C 74, 26.2.2016, p. 4–10. The Commission may consult the group on any matter relating to marine and fisheries biology, fishing gear technology, fisheries economics, fisheries governance, ecosystem effects of fisheries, aquaculture or similar disciplines. This report, on methods for supporting stock assessment in the Mediterranean (STECF-21-02), addresses the data checking and preparation for stock assessment once the data has been submitted following the annual data calls. The report provides an overview of the data errors and quality control carried out on both commercial landings data and MEDITS survey data. The analyses reported also address the small fraction of commercial catch with sampling gaps, and how these are assigned appropriate length frequency distributions. The results of these check and assignments are provided by species, GSA and country. Quality checks were carried out on Medits data check consistency of the main reporting files and highlighting where data inconsistencies occurred. Additionally the total landings reported to the European Commission under the Black & Med-Sea data call, the Fisheries Independent Data call and the Annual Economic Report data call were compared at species aggregated to GSA. Some important differences were observed and these are reported. In addition the EWG reviewed a technical report on the sampling of commercial catch in the Greek Fisheries, the review and some suggested further work are included in this report.

Description: European Union, Joint Research Centre

Description: Published

Description: Refereed

Description: Large stocks of soil organic carbon (SOC) have accumulated in the northern hemisphere permafrost region, but their current mounts and future fate remain uncertain. By analyzing an unprecedented dataset combining 〉2,700 soil profiles with environmental variables in a geospatial framework, we generated spatially explicit estimates of permafrost-region SOC stocks, quantified spatial heterogeneity, and identified key environmental predictors. We estimated 1014−175+194 Pg C are stored in the top 3 m of permafrost region soils. The greatest uncertainties occurred in circumpolar toe-slope positions and in flat areas of the Tibetan region. We found that soil wetness index and elevation are the dominant topographic controllers and surface air temperature (circumpolar region) and precipitation (Tibetan region) are significant climatic controllers of SOC stocks. Our results provide the first high-resolution geospatial assessment of permafrost region SOC stocks and their relationships with environmental factors, which are crucial for modeling the response of permafrost affected soils to changing climate.

Description: Let G k , n ℂ for 2 ≤ k

Description: Motivated by applications in evacuation planning, we consider a problem of optimizing flow with arc reversals in which the transit time depends on the orientation of the arc. In the considered problems, the transit time on an arc may change when it is reversed, contrary to the problems considered in the existing literature. Extending the existing idea of auxiliary network construction to allow asymmetric transit time on arcs, we present strongly polynomial time algorithms for solving single-source-single-sink maximum dynamic contraflow problem and quickest contraflow problem. The results are substantiated by a computational experiment in a Kathmandu road network. An algorithm to solve the corresponding earliest arrival contraflow problem with a pseudo-polynomial-time complexity is also presented. The partial contraflow approach for the corresponding problems has also been discussed.

Description: Mixed estimators in nonparametric regression have been developed in models with one response. The biresponse cases with different patterns among predictor variables that tend to be mixed estimators are often encountered. Therefore, in this article, we propose a biresponse nonparametric regression model with mixed spline smoothing and kernel estimators. This mixed estimator is suitable for modeling biresponse data with several patterns (response vs. predictors) that tend to change at certain subintervals such as the spline smoothing pattern, and other patterns that tend to be random are commonly modeled using kernel regression. The mixed estimator is obtained through two-stage estimation, i.e., penalized weighted least square (PWLS) and weighted least square (WLS). Furthermore, the proposed biresponse modeling with mixed estimators is validated using simulation data. This estimator is also applied to the percentage of the poor population and human development index data. The results show that the proposed model can be appropriately implemented and gives satisfactory results.

Description: In the present paper, we summarize the results of the research devoted to the problem of stability of the fluid flow moving in a channel with flexible walls and interacting with the walls. The walls of the vessel are subject to traveling waves. Experimental data show that the energy of the flowing fluid can be transferred and consumed by the structure (the walls), inducing “traveling wave flutter.” The problem of stability of fluid-structure interaction splits into two parts: (a) stability of fluid flow in the channel with harmonically moving walls and (b) stability of solid structure participating in the energy exchange with the flow. Stability of fluid flow, the main focus of the research, is obtained by solving the initial boundary value problem for the stream function. The main findings of the paper are the following: (i) rigorous formulation of the initial boundary problem for the stream function, ψ x , y , t , induced by the fluid-structure interaction model, which takes into account the axisymmetric pattern of the flow and “no-slip” condition near the channel walls; (ii) application of a double integral transformation (the Fourier transformation and Laplace transformation) to both the equation and boundary and initial conditions, which reduces the original partial differential equation to a parameter-dependent ordinary differential equation; (iii) derivation of the explicit formula for the Fourier transform of the stream function, ψ ˜ k , y , t ; (iv) evaluation of the inverse Fourier transform of ψ ˜ k , y , t and proving that reconstruction of ψ x , y , t can be obtained through a limiting process in the complex k -plane, which allows us to use the Residue theorem and represent the solution in the form of an infinite series of residues. The result of this research is an analytical solution describing blood flowing through a channel with flexible walls that are being perturbed in the form of a traveling wave.

Description: Analytical solutions for the transient single-phase and two-phase inward solid-state diffusion and solidification applied to the radial cylindrical and spherical geometries are proposed. Both solutions are developed from the differential equation that treats these phenomena in Cartesian coordinates, which are modified by geometric correlations and suitable changes of variables to achieve closed-form solutions. The modified differential equations are solved by using two well-known closed-form solutions based on the error function, and then equations are obtained to analyze the diffusion interface position as a function of time and position in cylinders and spheres. These exact correlations are inserted into the closed-form solutions for the slab and are used to update the roots for each radial position of the moving boundary interface. The predictions provided by the proposed analytical solutions are validated against the results of a numerical approach. Finally, a comparative study of diffusion in slabs, cylinders, and spheres is also presented for single-phase and two-phase solid-state diffusion and solidification, which shows the importance of the effects imposed by the radial cylindrical and spherical curvatures with respect to the Cartesian coordinate system in the process kinetics. The analytical model is proved to be general, as far as, a semi-infinite solution for diffusion problems with phase change exists in the form of the error function, which enables exact closed-form analytical solutions to be derived, by updating the root at each radial position the moving boundary interface.

Description: The contraflow approach has been extensively considered in the literature for modeling evacuations and has been claimed, due to its lane-direction-reversal capability, as an efficient idea to speed up the evacuation process. This paper considers the contraflow evacuation model on network with prioritized capacitated vertices that allows evacuees to be held at intermediate spots too, respecting their capacities and priority order. In particular, it studies the maximum flow evacuation planning problem and proposes polynomial and pseudo-polynomial time solution algorithms for static network and dynamic multinetwork, respectively. A real dataset of Kathmandu road network with evacuation spaces is considered to implement the algorithm designed for dynamic multinetwork and to observe its computational performance.

Description: This paper presents a mathematical model of glucose-insulin dynamics which is specific for type 2 diabetic patients. The general modelling is obtained by simplification of a global compartmental model by John Thomas Sorensen. The model parameters are estimated using nonlinear optimization and data collected in Rwanda for type 2 diabetic patients. In order to identify and evaluate possible abnormalities of type 2 diabetic patients, the Sampling Importance Resampling (SIR) particle filtering algorithm is used and implemented through discretization of the developed mathematical model. This process is done by clamping insulin and glucose concentrations at around clinical trial values as proposed by Defronzo. Furthermore, for detecting potential abnormalities in type 2 diabetic patients, we compare our results with results obtained from a simulation of the mathematical model for healthy subjects. The proposed mathematical model allows further investigation of the dynamic behavior of glucose, insulin, glucagon, stored insulin, and labile insulin in different organs for type 2 diabetic patients.

Description: Research has shown that current health expenditure in most countries, especially in sub-Saharan Africa, is inadequate and unsustainable. Yet, fraud, abuse, and waste in health insurance claims by service providers and subscribers threaten the delivery of quality healthcare. It is therefore imperative to analyze health insurance claim data to identify potentially suspicious claims. Typically, anomaly detection can be posited as a classification problem that requires the use of statistical methods such as mixture models and machine learning approaches to classify data points as either normal or anomalous. Additionally, health insurance claim data are mostly associated with problems of sparsity, heteroscedasticity, multicollinearity, and the presence of missing values. The analyses of such data are best addressed by adopting more robust statistical techniques. In this paper, we utilized the Bayesian quantile regression model to establish the relations between claim outcome of interest and subject-level features and further classify claims as either normal or anomalous. An estimated model component is assumed to inherently capture the behaviors of the response variable. A Bayesian mixture model, assuming a normal mixture of two components, is used to label claims as either normal or anomalous. The model was applied to health insurance data captured on 115 people suffering from various cardiovascular diseases across different states in the USA. Results show that 25 out of 115 claims (21.7%) were potentially suspicious. The overall accuracy of the fitted model was assessed to be 92%. Through the methodological approach and empirical application, we demonstrated that the Bayesian quantile regression is a viable model for anomaly detection.

Description: In this paper, we study a decomposition D -module structure of the polynomial ring. Then, we illustrate a geometric interpretation of the Specht polynomials. Using Brauer’s characterization, we give a partial generalization of the fact that factors of the discriminant of a finite map π : spec B ⟶ spec A generate the irreducible factors of the direct image of B under the map π .

Description: We investigate a class of locally conformal almost Kähler structures and prove that, under some conditions, this class is a subclass of almost Kähler structures. We show that a locally conformal almost Kähler manifold admits a canonical foliation whose leaves are hypersurfaces with the mean curvature vector field proportional to the Lee vector field. The geodesibility of the leaves is also characterized, and their minimality coincides with the incompressibility of the Lee vector field along the leaves.

Description: We provide a characterization of the finite dimensionality of vector spaces in terms of the right-sided invertibility of linear operators on them.

Description: The concept of frames in Hilbert spaces continues to play a very interesting role in many kinds of applications. In this paper, we study the notion of dual continuous K -g-frames in Hilbert spaces. Also, we establish some new properties.

Description: Any continuous function with values in a Hausdorff topological space has a closed graph and satisfies the property of intermediate value. However, the reverse implications are false, in general. In this article, we treat additional conditions on the function, and its graph for the reverse to be true.

Description: For a Gaussian prime π and a nonzero Gaussian integer β = a + b i ∈ ℤ i with a ≥ 1 and β ≥ 2 + 2 , it was proved that if π = α n β n + α n − 1 β n − 1 + ⋯ + α 1 β + α 0 ≕ f β where n ≥ 1 , α n ∈ ℤ i 0 , α 0 , … , α n − 1 belong to a complete residue system modulo β , and the digits α n − 1 and α n satisfy certain restrictions, then the polynomial f x is irreducible in ℤ i x . For any quadratic field K ≔ ℚ m , it is well known that there are explicit representations for a complete residue system in K , but those of the case m ≡ 1   mod 4 are inapplicable to this work. In this article, we establish a new complete residue system for such a case and then generalize the result mentioned above for the ring of integers of any imaginary quadratic field.

Description: For parabolic Shilov equations with continuous coefficients, the problem of finding classical solutions that satisfy a modified initial condition with generalized data such as the Gelfand and Shilov distributions is considered. This condition arises in the approximate solution of parabolic problems inverse in time. It linearly combines the meaning of the solution at the initial and some intermediate points in time. The conditions for the correct solvability of this problem are clarified and the formula for its solution is found. Using the results obtained, the corresponding problems with impulse action were solved.

Description: Combinatorial sums and binomial identities have appeared in many branches of mathematics, physics, and engineering. They can be established by many techniques, from generating functions to special series. Here, using a simple mathematical induction principle, we obtain a new combinatorial sum that involves ordinary powers, falling powers, and binomial coefficient at once. This way, and without the use of any complicated analytic technique, we obtain a result that already exists and a generalization of an identity derived from Sterling numbers of the second kind. Our formula is new, genuine, and several identities can be derived from it. The findings of this study can help for better understanding of the relation between ordinary and falling powers, which both play a very important role in discrete mathematics.

Description: A graph G is called cycle books B 4 , m , 2 if G consists of m cycles C 4 with a common path P 2 . Figueroa-Centeno, Ichishima, and Muntaner-Batle conjecture that the graph B 4 , m , 2 is super edge-magic total if and only if m is even or m ≡ 5   mod 8 . In this article, we prove this conjecture for m  ≥ 36 and m  = 0 mod (2).

Description: A mapping   ℸ :   V G ⟶ N ∪ 0 for a connected graph G = V , E is called a radial radio labelling if it satisfies the inequality     ℸ x −   ℸ   y + d x , y ≥ rad G + 1 ∀ x , y ∈ V G , where rad G is the radius of the graph G . The radial radio number of ℸ denoted by r r ℸ   is the maximum number mapped under ℸ . The radial radio number of G denoted by r r G is equal to min { r r ℸ   / ℸ   is a radial radio labelling of G }.

Description: For a polynomial p z of degree n , it follows from the maximum modulus theorem that max z = R ≥ 1 p z ≤ R n max z = 1 p z . It was shown by Ankeny and Rivlin that if p z ≠ 0 for z

Description: In this paper, we introduce a new class of contact pseudo framed (CPF)-manifolds M , g , f , λ , ξ by a real tensor field f of type 1,1 , a real function λ such that f 3 = λ 2 f where ξ is its characteristic vector field. We prove in our main Theorem 2 that M admits a closed 2-form Ω if λ is constant. In 1976, Blair proved that the vector field ξ of a normal contact manifold is Killing. Contrary to this, we have shown in Theorem 2 that, in general, ξ of a normal CPF-manifold is non-Killing. We also have established a link of CPF-hypersurfaces with curvature, affine, conformal collineations symmetries, and almost Ricci soliton manifolds, supported by three applications. Contrary to the odd-dimensional contact manifolds, we construct several examples of even- and odd-dimensional semi-Riemannian and lightlike CPF-manifolds and propose two problems for further consideration.

Description: In this article, we present an approach which allows taking into account the effect of extreme values in the modeling of financial asset returns and in the valorisation of associated options. Specifically, the marginal distribution of asset returns is modelled by a mixture of two Gaussian distributions. Moreover, we model the joint dependence structure of the returns using a copula function, the extremal one, which is suitable for our financial data, particularly the extreme values copulas. Applications are made on the Atos and Dassault Systems actions of the CAC40 index. Monte Carlo method is used to compute the values of some equity options such as the call on maximum, the call on minimum, the digital option, and the spreads option with the basket (Atos, Dassault systems) as underlying.

Description: This paper presents a new approach to determine the number of solutions of three-variable Frobenius-related problems and to find their solutions by using order reducing methods. Here, the order of a Frobenius-related problem means the number of variables appearing in the problem. We present two types of order reduction methods that can be applied to the problem of finding all nonnegative solutions of three-variable Frobenius-related problems. The first method is used to reduce the equation of order three from a three-variable Frobenius-related problem to be a system of equations with two fixed variables. The second method reduces the equation of order three into three equations of order two, for which an algorithm is designed with an interesting open problem on solutions left as a conjecture.

Description: In this paper, we present and establish a new result on the stability analysis of solutions for fuzzy nonlinear fractional differential equations by extending Lyapunov’s direct method from the fuzzy ordinary case to the fuzzy fractional case. As an application, several examples are presented to illustrate the proposed stability result.

Description: Proposed in 1937, the Collatz conjecture has remained in the spotlight for mathematicians and computer scientists alike due to its simple proposal, yet intractable proof. In this paper, we propose several novel theorems, corollaries, and algorithms that explore relationships and properties between the natural numbers, their peak values, and the conjecture. These contributions primarily analyze the number of Collatz iterations it takes for a given integer to reach 1 or a number less than itself, or the relationship between a starting number and its peak value.

Description: This article deals with the study of mathematical models and the assessment of the stability of the motion of ships, investigating properties of the system such as kinetics and stability. This is essential for the selection of suitable control methods according to the requirements set out for the problem. Some control methods require the author to specify control parameters before the operation of the system can be started. Therefore, the survey of the article is useful for the above problem. Control methods through simulation results (PID controller, lag compensator, and lead compensator) give me results that reflect properties of the system (the stability of the operation cycle of the ship model). In addition, control methods for this model, which serve for research and education, are also presented below. Simulation is done by Matlab.

Description: The study recognized the worth of understanding the how’s of handling censoring and censored data in survival analysis and the potential biases it might cause if researchers fail to identify and handle the concepts with utmost care. We systematically reviewed the concepts of censoring and how researchers have handled censored data and brought all the ideas under one umbrella. The review was done on articles written in the English language spanning from the late fifties to the present time. We googled through NCBI, PubMed, Google scholar and other websites and identified theories and publications on the research topic. Revelation was that censoring has the potential of biasing results and reducing the statistical power of analyses if not handled with the appropriate techniques it requires. We also found that, besides the four main approaches (complete-data analysis method; imputation approach; dichotomizing the data; the likelihood-based approach) to handling censored data, there were several other innovative approaches to handling censored data. These methods include censored network estimation; conditional mean imputation method; inverse probability of censoring weighting; maximum likelihood estimation; Buckley-Janes least squares algorithm; simple multiple imputation strategy; filter algorithm; Bayesian framework; β -substitution method; search-and-score-hill-climbing algorithm and constraint-based conditional independence algorithm; frequentist; Markov chain Monte Carlo for imputed data; quantile regression; random effects hierarchical Cox proportional hazards; Lin’s Concordance Correlation Coefficient; classical maximum likelihood estimate. We infer that the presence of incomplete information about subjects does not necessarily mean that such information must be discarded, rather they must be incorporated into the study for they might carry certain relevant information that holds the key to the understanding of the research. We anticipate that through this review, researchers will develop a deeper understanding of this concept in survival analysis and select the appropriate statistical procedures for such studies devoid of biases.

Description: We extend the well-known characterizations of convergence in the spaces l p ( 1 ≤ p

Description: In this paper, we are interested in the inverse problem of the determination of the unknown part ∂ Ω , Γ 0 of the boundary of a uniformly Lipschitzian domain Ω included in ℝ N from the measurement of the normal derivative ∂ n v on suitable part Γ 0 of its boundary, where v is the solution of the wave equation ∂ t t v x , t − Δ v x , t + p x v x = 0 in Ω × 0 , T and given Dirichlet boundary data. We use shape optimization tools to retrieve the boundary part Γ of ∂ Ω . From necessary conditions, we estimate a Lagrange multiplier k Ω which appears by derivation with respect to the domain. By maximum principle theory for hyperbolic equations and under geometrical assumptions, we prove a uniqueness result of our inverse problem. The Lipschitz stability is established by increasing of the energy of the system. Some numerical simulations are made to illustrate the optimal shape.

Description: This report reviews the current situation as regards to the Marine Strategy Framework Directive (MSFD) Descriptor 1 (Biodiversity) for pelagic habitats and serves as a basis for a workshop with Member States experts and scientists that will be held on March 9-10 2021. Recommendations are in the concluding section. Pelagic habitats cover the 71% of Earth’s surface and play an essential role in regulating temperature on land, producing oxygen and food. They are also a management challenge where the alterations of their physical, chemical and biological characteristics negatively impact their ecosystem functioning and services (e.g. provisioning services). To address these challenges, the MSFD has required the assessment of pelagic habitats against environmental targets to reach Good Environmental Status (GES). A key step in the pelagic habitat assessment is a thorough understanding of its physical, chemical and biological processes and the drivers that underlie the spatiotemporal variability in its ecologically relevant ecosystem components. However, pelagic assessments to date have not sufficiently addressed the functional and structural characteristics of pelagic habitats processes, which is limiting our ability to inform on their environmental status and to disentangle the anthropogenic drivers. This report evaluates previously published work on pelagic habitats assessments considering the actions and targets to meet the MSFD requirements. To do this, the report (i) summarises the main drivers of variation in pelagic habitat characterization; (ii) reviews the common empirical approaches used to assess pelagic habitats, the advantages, and challenges; and finally (iii) exposes a set of recommendations for characterising pelagic habitats in EU waters. Since the pelagic habitats are made of a highly dynamic fluid, appropriate spatiotemporal scales regarding data and methods must be considered to assess their GES. This applies in particular to the selected indicators to propose the effective and quantifiable GES targets that need to be reached.

Description: Geological archives record multiple reversals of Earth’s magnetic poles, but the global impacts of these events, if any, remain unclear. Uncertain radiocarbon calibration has limited investigation of the potential effects of the last major magnetic inversion, known as the Laschamps Excursion [41 to 42 thousand years ago (ka)]. We use ancient New Zealand kauri trees (Agathis australis) to develop a detailed record of atmospheric radiocarbon levels across the Laschamps Excursion. We precisely characterize the geomagnetic reversal and perform global chemistry-climate modeling and detailed radiocarbon dating of paleoenvironmental records to investigate impacts. We find that geomagnetic field minima ~42 ka, in combination with Grand Solar Minima, caused substantial changes in atmospheric ozone concentration and circulation, driving synchronous global climate shifts that caused major environmental changes, extinction events, and transformations in the archaeological record.

Description: Various space missions, including the Russian and Chinese interplanetary exploration collaboration in 2011 and the Phobos-Grunt space project to be relaunched by the Chinese in 2025, carry a soil preparation system (SOPSYS), which is an instrument used for scientific experiments. The design and manufacture of this precision instrument require stringent manufacturing processes and workflow of the highest quality, with every process in the project carefully monitored and controlled. All processes should be completed within the deadline so that the space project can be launched at the scheduled time. The colored Petri net (CPN) modeling method can describe a variety of resource types and execution logic, and it can be formally verified. Based on these advantages, we clearly describe the complex structure of the SPOSYS unit production process. In addition, we use critical time and the 6 sigma system to evaluate the availability and reliability of workflows, and we use elimination and simplification (ECRS) methods and constraint theory to improve the manufacturing process of the SOPSYS unit. We further provide optimization theories, methods, and insights for workflow management in time-sensitive and independent manufacturing systems.

Description: Automated seizure detection system based on electroencephalograms (EEG) is an interdisciplinary research problem between computer science and neuroscience. Epileptic seizure affects 1% of the worldwide population and can lead to severe long-term harm to safety and life quality. The automation of seizure detection can greatly improve the treatment of patients. In this work, we propose a neural network model to extract features from EEG signals with a method of arranging the dimension of feature extraction inspired by the traditional method of neurologists. A postprocessor is used to improve the output of the classifier. The result of our seizure detection system on the TUSZ dataset reaches a false alarm rate of 12 per 24 hours with a sensitivity of 59%, which approaches the performance of average human detector based on qEEG tools.

Description: The influence of size effect on the hydromechanical behavior of rock mass has long been recognized. As a result, analysis of the rock mass size effect has been developed. However, when conducting size effect studies, the representativeness of the sample is less considered. Therefore, combining the existing statistical methods and sampling methods, a comprehensive representative sampling method for rock mass is present. In this method, a large number of sample statistics of different sizes are provided in the progressive coverage method; then, the plane density of the track length is defined as the value of stratification to perform stratified sampling for representative samples. Furthermore, it is applied to a joint network model generated in accordance with the actual situation and compared with those of other methods. The sampling results show that the proposed method can provide a certain reference value for studying the scale-dependent behavior of rock mass mechanical parameters.

Description: The Linxing area is located in the north of the eastern margin of the Ordos Basin, which has great resource potential for tight gas. In this paper, fluid inclusion analysis and basin modeling are the main means to clarify the gas accumulation mechanism of the Upper Paleozoic in the Linxing area. Petrographic analysis shows that fluid inclusions can be classified into 5 types: aqueous inclusions, hydrocarbon-bearing aqueous inclusions, hydrocarbon inclusions, crystal-bearing aqueous inclusions, and aqueous-carbonic inclusions. According to the statistical analysis of homogenization temperature and salinity of fluid inclusions, combined with the burial-thermal evolution, the study area was divided into 3 areas: the inner-magma baking area, the middle-anomal thermal area, and the outer-normal thermal area. The gas accumulation characteristics are differences among the 3 areas, the closer to Zijinshan magmatic pluton, the earlier gas accumulation period; and the vertical gas accumulation in the inner-magma baking area and the middle-anomal thermal area was not a slow and gradual process from bottom to top. The period from the Middle Jurassic to the Early Cretaceous is the key period for rapid pressure accumulation in the Upper Paleozoic reservoirs, which is consistent with the period of natural gas accumulation. The area near the Zijinshan magmatic pluton was the high fluid potential area during the gas accumulation period, which indicates that natural gas and other fluids migrated from Zijinshan magmatic pluton to the surrounding area. It is concluded that in the Linxing area, the Zijinshan magmatic pluton had a significant impact on natural gas accumulation, and the natural gas accumulation model under the control of magmatic thermal-tectonic effect was proposed.

Description: With the increasingly close relations between cities in China, it is of great significance to explore the regular characteristics of the intercity connection. Through Tencent’s population migration heat and Baidu map big data, this paper analyzes the regular characteristics of the relations between complex cities based on such index as the rich node propensity index, preference level index, and relative heat index and also investigates the influence of geographical proximity factors on the external relations of different cities. The research has the following results. Firstly, the relations between cities have obvious club characteristics. The rich nodes tend to connect with the rich nodes, while the nonrich nodes tend to connect with the nonrich nodes. Secondly, the connection between cities has the effect of hierarchical proximity, and cities mainly establish spatial connections with cities of the same level and adjacent level. Thirdly, the relations between cities also have the effect of geographical proximity, and the degree of influence of geographical proximity in low-level cities is greater than that in high-level cities. Fourthly, the external connection mode of high-level cities is to establish close contact with high-level cities adjacent to the level, with strong attraction to low-level cities adjacent to the location at the same time. The low-level cities are closely related to the high-level cities adjacent to the location and other cities of geographical proximity or adjacent level. This study helps to further understand the complex characteristics and laws of intercity connections and urban networks.

Description: In Nepal, forest management priority is shifting to scientific management from conventional management. Though, the forest officials claims that scientific management is beneficial to the forest user groups, comparative financial assessment with conventional management remains unexplored. Following a case study approach, this study compares financial efficiency of two forest management systems in the community forests, focusing on benefit-cost ratio. The study conducted documents review, focus group discussions, and rapid survey to quantify costs and benefits from each forest management system. Conventional management gave a higher benefit-cost ratio to the forest user groups, irrespective of whether forest products are sold at a subsidized price or par with the market price. However, scientific management required high forest management costs and thus had a lower benefit-cost ratio. Sensitivity analysis between two systems revealed that conventional management gave a higher benefit-cost ratio in all cases. The study concludes that forest user groups would bear financial loss if they do not fix the price of the timber at par with the market in scientific management, and in such a case, the tagged price will be beyond affordability of the forest users. Furthermore, scientific management has discouraged kind contribution of users in managing forest. Besides, social and environmental consequences of scientific management cannot be ignored. Hence, the study argues for reconsidering current scientific management considering likely economic and social consequences to the forest user groups.

Description: The seepage of gas-liquid two-phase flow in fracture is a commonly found phenomenon in nature. To reveal the underlying mechanism and the critical condition of the chaos occurrence, a stochastic gas-liquid two-phase flow seepage model is established, and then investigated through a numerical simulation and a horizontal Hele-Shaw experiment. The numerical simulation and laboratory experiment results show that the seepage chaos of gas-liquid two-phase flow takes place when the relative saturation is in the range of gas relative saturation 44%-70%, and the occurrence probability can be expressed in polynomials. The chaos probability exceeds 80% when the relative saturation of gas is 47%-65%, and the chaos probability is 100% when the relative gas saturation is 57%-60%. It is found that the stochastic variation of gas connection cluster and the compressibility of gas lead to a remarkable change of pressure gradient of the gas-liquid flow both in magnitude and direction. Therefore, the turbulent flow is formed, the kinetic energy of fluid transport decreases gradually, and the flow is stopped at last.

Description: An effective porosity is defined as the ratio of volume of interconnected pore space to total volume of a porous sample. It controls the magnitude of fluid flow and is a key parameter in the assessment of recoverable resources. However, its accurate measurement in tight formations is challenging, due to their complex pore structure and lithofacies heterogeneity. In this study, porosities of sixteen lacustrine shale samples from the second Member of the Kongdian Formation (Ek2) in the Cangdong Sag, Bohai Bay Basin were measured and compared using multiple methods and sample sizes to compare and contrast the effective porosity results. The methods included helium pycnometry (HP; cubes of 1 cm3 and grains at 500-841 μm), water immersion porosimetry (WIP; cubes), mercury intrusion porosimetry (MIP; cubes), and nuclear magnetic resonance (NMR; cubes). Finally, samples were completely sealed using paraffin for bulk density measurements to evaluate the extent of potential clay swelling in shale samples involving probing fluids. Results from the HP, WIP, and MIP methods for skeletal density, bulk density, and effective porosity with cubic samples were compared. While very similar skeletal densities were found for all three methods, a lower bulk density, and therefore lower porosity, from the MIP approach can be attributed to the experimental conditions (e.g., vacuum efficiency, applied pressure, wettability of water/helium vs. mercury) and the probable presence of pores with diameters larger than 50 μm not measurable by MIP. Furthermore, the HP porosity of granular samples with 500-841 μm grain sizes can be regarded as approaching the total porosity. The complicated relationship between WIP and NMR porosities may result from the heat-induced volatilization of moisture in pores during NMR tests, and countercurrent imbibition of water replacing the residual hydrocarbons during the saturation process for sample preparation in both tests. The swelling behavior of the lacustrine Ek2 shale with water is not significant because of the low content of expansive clay minerals. In summary, the WIP and HP methods are recommended for effective porosity measurement, whereas the NMR and MIP methods are invaluable for the measurement of pore-size distribution, with additional information on the effective porosity.

Description: A tuned mass damper inerter (TMDI) is a new class of passive control device based on the inclusion of an inerter mechanism into a conventional tuned mass damper (TMD). The inerter device provides inertial resisting forces to the controlled system, through relatively small masses, converting it in a mechanism with the potential to enhance the performance of passive energy dissipating systems. This work presents a study of an optimal TMDI design through an exhaustive search process. TMDI device design using the cited parameter selection methodology consists in the determination of the damper critical damping ratio, ζTMDI, and frequency ratio, υTMDI, which result in the minimum structural response of a multidegree of freedom structural system, considering predefined values for mass ratio (µ) and inertance ratio (β). The used optimization process examines all possible damping device design parameter combinations to select the set of values that results in the best device performance to reduce response parameters in a structure. Four different optimization processes are performed by independently minimizing four performance indices: J1 associated to the reduction of the structure’s maximum peak displacement, J2 calculates the minimal RMS value for the structure’s peak displacement, J3 seeks by the minimal peak interstorey drift, and JP determines the lowest value for a linear weighted combination of the abovementioned three indices. A numerical example is developed with the purpose of validating the proposed optimization procedure and to evaluate the benefits of using TMDI as controlling devices for structures under seismic excitation, by carrying out a comparative analysis to contrast the performance of the optimization alternatives developed, running up to 1968192 cases. The obtained results show that devices designed based on exhaustive search optimization produce peak displacement reductions of up to 35% and peak structure displacement RMS reductions of up to 30%.

Description: The lower Silurian Longmaxi Formation hosts a highly productive shale gas play in the Zhaotong region of southern China. According to core observation, X-ray diffraction analyses, and scanning electron microscopy (SEM) observations, the shale comprises primarily quartz, carbonate minerals, and clay minerals, with minor amounts of plagioclase, K-feldspar, and pyrite. The clay mineral content ranges from 15.0% to 46.1%, with an average of 29.3% in the Zhaotong region. Organic geochemical analyses show that the Longmaxi Formation has good potential for shale gas resources by calculating total organic carbon, vitrinite reflectance, and gas content. Scanning electron microscope images demonstrate that reservoir pore types in the Longmaxi shale include organic pores, interparticle pores, intercrystalline pores, intraparticle pores, and fractures. Reservoir distribution is controlled by lithofacies, mineral composition, and geochemical factors. In addition, we investigated the relationships between reservoir parameters and production from 15 individual wells in the Zhaotong region by correlation coefficients. As a result, the brittleness index, total organic carbon (TOC), porosity, and gas content were used to define high-quality reservoirs in the Longmaxi shale. Based on these criteria, we mapped the thickness and distribution of high-quality reservoirs in the Longmaxi Formation and selected highlighted several key sites for future exploration and development.

Description: In the present study, we employ fluorescence spectroscopy, dynamic light scattering, and molecular docking methods. Binding of anticancer drug anastrozole with human lysozyme (HL) is studied. Binding of anastrozole to HL is moderate but spontaneous. There is anastrozole persuaded hydrodynamic change in HL, leading to molecular compaction. Binding of anastrozole to HL also decreased in vitro lytic activity of HL. Molecular docking results suggest the electrostatic interactions and van der Waals forces played key role in binding interaction of anastrozole near the catalytic site. Binding interaction of anastrozole to proteins other than major transport proteins in blood can significantly affect pharmacokinetics of this molecule. Hence, rationalizing drug dosage is important. This study also points to unrelated effects that small molecules bring in the body that are considerable and need thorough investigation.

Description: Controlling and maintaining the orientation of the balloon-borne gondola for high-altitude flight is a prerequisite for ensuring the pointing control of observation instruments. When the balloon-borne gondola is flying in the stratosphere of the atmosphere, the existing external interferences will be converted into the coupling moment to the azimuth control system. Meanwhile, those uncertain factors and the frictional nonlinearity of the control system will also cause a certain magnitude of coupling moment. The existence of such coupling moment largely impacts on the accuracy and stability of the orientation control for the angular momentum exchange devices of the balloon-borne gondola. To address such an issue, this paper proposes and implements a novel type of integrated decoupler device. With this decoupler adopted, the aziDmuth control system could sense the existence of coupling torque and azimuth fluctuations quickly and suppress the influences of external interference, uncertain factors, and system structure nonlinearity on the azimuth control effectively, thereby improving the control accuracy of the azimuth control system. Both simulations and experiments are conducted to verify the effectiveness of the proposed device. The results show that the integration of the decoupler and the controller of the azimuth control system provide the azimuth control of the balloon-borne gondola with high accuracy and stability. Such a decoupler device design has a broad potential and could not only be used for balloon-borne gondola control but also could be applied onto other control systems using angular momentum exchange devices as actuators.

Description: When mine water inrush accidents occur, timely and accurately identifying the water inrush source plays an important role in determining the cause of water inrush and making a solution to a disaster. According to the differences of water chemical composition in each water sources of mine, eight kinds of indicators of water chemical composition were selected as sample variables for water inrush source identification. On this basis, an identification model of water inrush source was established by using principal component analysis (PCA) and Fisher discriminant analysis (FDA) combined. The model was used to identify the water inrush source of 14 groups of training samples and 12 groups of samples to be judged in different water sources of the Xiandewang coal mine, and it was compared with the results of the conventional identification model which used the FDA method. Results of this study showed that having processed data by using the PCA method can effectively eliminate the effects of information superposition between sample indicators, and the identification accuracy of mine water inrush source was significantly increased. Related study in this paper can provide some basis and reference for the study of mine water inrush source identification technology.

Description: The abundance of organic matter in shales, which has a direct effect on the hydrocarbon generation potential of shales, is an important organic geochemical parameter for evaluating shale gas reservoirs. The total organic carbon content (TOC content) in shale is controlled by the abundance of original sedimentary organic matter. Therefore, it is very important to study the mechanism of organic matter enrichment in shale. In this paper, the Lower Cambrian marine shales from the Lower Yangtze region are selected as the research subject, most of which originate from a typical area well called Well JXY1. The degree of pyritization (DOP) is used to characterize the redox environment of the water body, while the P/Al ratio is used to analyze the biological productivity of paleoseawater. The paleosalinity of seawater is calculated via carbon and oxygen isotope analysis. In addition, the early Cambrian hydrothermal activities were studied by using core description; Si, Al, Fe, and Mn elemental analysis; and oxygen isotope calculations. The results show that during the early Cambrian Wangyinpu sedimentary period, the seawater was an anaerobic water body with H2S, and the oxygen concentration was approximately 0 mL/L. In the middle stages of the Wangyinpu sedimentary period, the water body had the strongest reducibility and the highest biological productivity. Moreover, the paleoocean in this period between the Yangtze plate and the Cathaysian plate was greatly affected by hydrothermal activities, with temperatures ranging from 90°C to 120°C. Active hydrothermal activities promoted high biological productivity and an anaerobic environment, both of which were conducive to the preservation and enrichment of organic matter, resulting in extremely high TOC content in the Wangyinpu shales (from 6.5% to approximately 16%).

Description: Gates are important operating facilities and resources in civil airports. It is a core task in the airport operation management to select reasonable gates for inbound and outbound flights. We present a continuous time formulation with second-order cone programming (SOCP) for the gate assignment problem which allocates flights to available gates to optimize both the transfer time of passengers and the robustness of the airport operations schedules. The problem is formulated as a mixed integer nonlinear program, and then, the quadratic objective that minimizes the walking distance of transferring passengers is linearized, and the objective that minimizes the variance of idle time at the gates is transformed to a second-order cone constraint with a linear objective function. Then, a Lagrangian relaxation algorithm is developed by exploiting the problem structure. Computational tests are carried out to illustrate the efficiency of the model and the algorithms. It is shown that the continuous time formulation is more efficient than the existing model, and the Lagrangian relaxation algorithm can obtain better solutions faster than a commercial solver.

Description: In this paper, we propose an innovative method for conventional triaxial tests of concrete with a confining cell. The polyvinyl chloride (PVC) pipe is used as a mould to cast concrete and also as a membrane to isolate the concrete specimen from oil under confinements. This method is termed as PMM (i.e., PVC pipe is used as a mould and membrane). However, a heat-shrink sleeve is used as a membrane in the traditional test method (TMM). Specimens were made from mortar without coarse aggregates in the present experiment. Under six confinements (0–70 MPa), the conventional triaxial compression tests were performed on ultrahigh-strength (150 MPa) and high-strength (82 MPa) mortar specimens by PMM and TMM. The results indicate the following: (i) there is a characteristic confinement p0; when the confinement is lower than p0, the strength by PMM is higher than that by TMM; on the contrary, when the confinement is higher than p0, the strengths by both methods are almost identical. In this work, p0 is between 0 and 5 MPa. (ii) When the confinement is 5–70 MPa, the relationship between the peak stress of high-strength mortar and confinement is characterized by a monotonically rising straight line; however, a monotonically rising upward convex curve describes the peak stress of ultrahigh-strength mortar related to the confinement. (iii) The residual strength using PMM is significantly higher than that using TMM at zero confinement or lower confinements, but the residual strengths by these two methods are approximately identical at higher confinements. (iv) The transverse cracks appear in the mortar specimen inside the PVC pipe after enduring a triaxial loading using PMM. However, there is no such phenomenon when TMM is applied.

Description: Electroencephalography-(EEG-) based control is a noninvasive technique which employs brain signals to control electrical devices/circuits. Currently, the brain-computer interface (BCI) systems provide two types of signals, raw signals and logic state signals. The latter signals are used to turn on/off the devices. In this paper, the capabilities of BCI systems are explored, and a survey is conducted how to extend and enhance the reliability and accuracy of the BCI systems. A structured overview was provided which consists of the data acquisition, feature extraction, and classification algorithm methods used by different researchers in the past few years. Some classification algorithms for EEG-based BCI systems are adaptive classifiers, tensor classifiers, transfer learning approach, and deep learning, as well as some miscellaneous techniques. Based on our assessment, we generally concluded that, through adaptive classifiers, accurate results are acquired as compared to the static classification techniques. Deep learning techniques were developed to achieve the desired objectives and their real-time implementation as compared to other algorithms.

Description: This paper studies the global stability of a discrete-time pathogen dynamic model with both cell-mediated and antibody immune responses. Both latently and actively infected cells are incorporated into the model. We discretize the continuous-time model by using the nonstandard finite difference (NSFD) method. We establish that NSFD preserves the nonnegativity and boundedness of the solutions of the model. We derive four threshold parameters which govern the existence and stability of the steady states. We establish by using the Lyapunov method, the global stability of the five steady states of the model. We illustrate our theoretical results by using numerical simulations.

Description: The high-temperature gas-cooled reactor pebble-bed module (HTR-PM) nuclear power plant consists of two nuclear steam supply system modules, each of which drives the steam turbine by the superheated steam flow and is fed by the heated-up water flow. The shared steam/water system induces mutual effects on normal operation conditions and transients of the nuclear power plant, which is worthy of safety concerns and intensive study. In this paper, a coupling code package was developed with the TINTE and vPower codes to understand how the HTR-PM operated. The TINTE code was used to analyze the reactor core and primary circuit, while the vPower code simulated the steam/water flow in the conventional island. Two TINTE models were built and coupled to one vPower model through the data exchange in the steam generator models. Using this code package, two typical transients were simulated by decreasing the primary flow rate or introducing the negative reactivity of one module. Important parameters, including the reactor power, the fuel temperature, and the reactor inlet and outlet helium temperatures of two modules, had been studied. The calculation results preliminarily proved that this code package can be further used to evaluate working performance of the HTR-PM.

Description: Using standard techniques from geometric quantization, we rederive the integral product of functions on ℝ2 (non-Euclidian) which was introduced by Pierre Bieliavsky as a contribution to the area of strict quantization. More specifically, by pairing the nontransverse real polarization on the pair groupoid ℝ2×ℝ¯2, we obtain the well-defined integral transform. Together with a convolution of functions, which is a natural deformation of the usual convolution of functions on the pair groupoid, this readily defines the Bieliavsky product on a subset of L2ℝ2.

Description: Chloride corrosion test was carried out in 4% NaCl solution to study the chloride corrosion resistance of rubber concrete. Rubber concrete was prepared by using 20 mesh, 1∼3 mm, and 3∼6 mm rubber particles instead of sand by 5%, 10%, 15%, and 20% of the cementitious material mass. The P-wave velocity and compressive strength of rubber concrete were measured. The microstructure of rubber concrete corroded by chloride was analyzed by SEM. The micromorphology was compared with the macrofailure characteristics under uniaxial compression. The results show that the rubber concrete was still in the early stage of erosion. With the increase of immersion time at the age of 110 days, the P-wave velocity and compressive strength of concrete were generally on the rise. Furthermore, during the period of erosion, the mechanical properties of rubber concrete increased with the increase of rubber particle size and decreased with the increase of the content. Therefore, when the rubber particle size was 3∼6 mm and the content was 5%, the antierosion performance was the best. This study has a certain guiding significance for the chloride corrosion resistance of rubber concrete.

Description: Background. Young people are challenged with sexual and reproductive health (SRH) problems due to limited access to services and information. It contributes a high burden of sexually transmitted disease, unsafe abortion, and premature mortality, especially in low-income countries like Ethiopia. Hence, this study aimed at assessing the SRH service utilization and associated factors among college students at West Arsi Zone in Oromia region, Ethiopia. Methods. Institutional-based cross-sectional study was conducted among 519 randomly selected college students from January 01, 2019, up to April 30, 2019. Data were collected through self-administered pretested questionnaires. Data entry and analysis for descriptive and logistic regression models were performed by using SPSS (version 23). The result was declared as statistically significant at p 

Description: In this paper, an intelligent modeling approach is presented to predict the shear strength of the internal reinforced concrete (RC) beam-column joints and used to analyze the sensitivity of the influence factors on the shear strength. The proposed approach is established based on the famous boosting-family ensemble machine learning (ML) algorithms, i.e., gradient boosting regression tree (GBRT), which generates a strong predictive model by integrating several weak predictors, which are obtained by the well-known individual ML algorithms, e.g., DT, ANN, and SVM. The strong model is boosted as each weak predictor has its own weight in the final combination according to the performance. Compared with the conventional mechanical-driven shear strength models, e.g., the well-known modified compression field theory (MCFT), the proposed model can avoid the complicated derivation process of shear mechanism and calibration of the involved empirical parameters; thus, it provides a more convenient, fast, and robust alternative way for predicting the shear strength of the internal RC joints. To train and test the GBRT model, a total of 86 internal RC joint specimens are collected from the literatures, and four traditional ML models and the MCFT model are also employed as comparisons. The results indicate that the GBRT model is superior to both the traditional ML models and MCFT model, as its degree-of-fitting is the highest and the predicting dispersion is the lowest. Finally, the model is used to investigate the influences of different parameters on the shear strength of the internal RC joint, and the sensitivity and importance of the corresponding parameters are obtained.

Description: In this paper, we present a survey of the inverse eigenvalue problem for a Laplacian equation based on available Cauchy data on a known part Γ0 and a homogeneous Dirichlet condition on an unknown part Γ0 of the boundary of a bounded domain, Ω⊂ℝN. We consider variations in the eigenvalues and propose a conformal mapping tool to reconstruct a part of the boundary curve of the two-dimensional bounded domain based on the Cauchy data of a holomorphic function that maps the unit disk onto the unknown domain. The boundary values of this holomorphic function are obtained by solving a nonlocal differential Bessel equation. Then, the unknown boundary is obtained as the image of the boundary of the unit disk by solving an ill-posed Cauchy problem for holomorphic functions via a regularized power expansion. The Cauchy data were restricted to a nonvanishing function and to the normal derivatives without zeros. We prove the existence and uniqueness of the holomorphic function being considered and use the fixed-point method to numerically analyze the results of convergence. We’ll calculate the eigenvalues and compare the result with the shape obtained via minimization functional method, as developed in a previous study. Further, we’ll observe via simulations the shape of Γ and if it preserves its properties with varying the eigenvalues.

Description: Generating relations involving the special functions have already proved their important role in mathematics and other fields of sciences. In this paper, we aim to provide some presumably new generating relations in connection with the generalized multi-index Bessel–Maitland function Jνjm,qλjm,γ.. The main results presented here, being very general, can yield a number of particular or equivalent identities, some of which are explicitly demonstrated.

Description: As the externalized carrier of intrinsic value, value decision-making is an important factor affecting the social value system. As an old Chinese saying goes, “A friend in need is a friend indeed,” crisis environment provides the background for the conflicts of multiple values, while individual social value orientation (SVO) determines the ranking of the value states. This paper defined the SVO types by means of Slider Measure method on the basis of environment description, constructed a decision-making game model in accordance with SVO differences, and finally analysed the mechanism of people’s decision-making. Taking the epidemic situation as the background, this paper conducted an empirical analysis with the sample of college students. The results showed that the most SVO types of college students were prosocial orientation, followed by individualistic orientation, altruistic orientation, and competitive orientation. In the crisis environment, individual SVO type and decision-making constituted a mapping relationship. There was an equilibrium point in the decision of prosocial orientation, and the dominant decision of altruistic orientation or individualistic orientation is relatively stable.

Description: High heterogeneity and nonuniformly distributed multiscale pore systems are two characteristics of the unconventional reservoirs, which lead to very complex transport mechanisms. Limited by inadequate computational capability and imaging field of view, flow simulation cannot be directly performed on complex pore structures. The traditional methods usually coarsen the grid to reduce the computational load but will lead to the missing microstructure information and inaccurate simulation results. To develop a better understanding of flow properties in unconventional reservoirs, this study proposed a new upscaling method integrated gray lattice Boltzmann method (GLBM) and pore network model (PNM), accounting for the fluid flow in heterogeneous porous media. This method can reasonably reduce the computational loads while preserving certain micropore characteristics. Verifications are conducted by comparing the simulation and experimental results on tight sandstones, and good agreements are achieved. The proposed method is proven to be capable of estimating bulk properties in highly heterogenous unconventional reservoirs. This method could contribute to the development of multiscale pore structure characterizations and enhance the understandings of fluid flow mechanisms in unconventional reservoirs.