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1.
PAPER (OA)
Heuristics for an Integrated Maintenance and Production Scheduling Problem on Parallel Machines with Stochastic Failures and Non-Resumable Jobs (2015)
Publication Date: 2015-08-04
Description: Maintenance activities can have a large impact on the performance of a production process and promised delivery dates. Therefore, maintenance and production planning should be handled as an integrated problem. In this paper, the problem of scheduling n jobs on m identical parallel machines is solved such that the expected makespan is minimised. The machines are affected by stochastic machine failures which are assumed to result in long production stops. To avoid this, preventive maintenance activities are planned beforehand. If a failure cannot be averted, a corrective maintenance has to be performed. Furthermore, it is assumed that jobs, interrupted by machine failure, have to be repeated (non-resumable case). In this paper, three construction heuristics and an Ant Colony System (ACS) algorithm are developed for solving this integrated problem. The excellent performance of the ACS as well as the benefit solving the problem in an integrated manner instead of sequentially, is shown in a numerical study.
Keywords: ddc:330 ; Parallel Machine Scheduling ; Maintenance ; Stochastic Failures ; Non-Resumable Jobs ; Ant Colony System
Repository Name: EconStor: OA server of the German National Library of Economics - Leibniz Information Centre for Economics
Language: eng
Type: doc-type:workingPaper
2.
PAPER (OA)
Determinants of governmental redistribution (2015)
Univ., Chair of Economic Order and Social Policy Würzburg
Publication Date: 2015-08-04
Description: This paper investigates the major drivers of governmental redistribution. We retest the Meltzer-Richard hypothesis and account for a plethora of political, institutional, and cultural forces that influence the scope of redistribution. Extended and harmonized data on effective redistribution recently provided by the SWIID allows for the assessment of the origins of governmental redistribution for a broad sample of countries. Our results confirm the Meltzer-Richard hypothesis, indicating that the link between market inequality and redistribution is even stronger when using perceived inequality measures. We support the decisive role of the median voter, though also approving a crucial role of top incomes. Political and institutional conditions as well as cultural aspects significantly influence governments in their decisions regarding the amount of redistribution.
Keywords: C23 ; D31 ; D72 ; H11 ; ddc:330 ; Redistribution ; Inequality ; Economic Policy ; Dynamic Panel Data
Repository Name: EconStor: OA server of the German National Library of Economics - Leibniz Information Centre for Economics
Language: eng
Type: doc-type:workingPaper
3.
PAPER (OA)
The labor market effect of demographic change: Alleviation for financing social security (2015)
Univ., Wirtschafts- und Sozialwiss. Fak. Rostock
Publication Date: 2015-08-04
Description: The paper shows the effect of demographic change on per capita burden of financing a PAYG social security system in the standard OLG model with frictional labor markets. Rising longevity and decreasing fertility both induce a rise in the employment level via increased capital accumulation and job openings. Simulations of the theoretical model show that this labor market effect indirectly crowds out part of the initial demographic shock's direct impact on per capita financing burden. This holds true for the generation at the period of impact as well as for the following generations.
Keywords: E24 ; E62 ; H55 ; ddc:330 ; OLG ; demographic change ; frictional labor market ; PAYG social security ; tax burden
Repository Name: EconStor: OA server of the German National Library of Economics - Leibniz Information Centre for Economics
Language: eng
Type: doc-type:workingPaper
4.
PAPER CURRENT
Vegetated canals mitigate nitrogen surplus in agricultural watersheds (2015)
Elsevier
Publication Date: 2015-08-03
Description: Publication date: 20 December 2015 Source:Agriculture, Ecosystems & Environment, Volume 212 Author(s): Giuseppe Castaldelli, Elisa Soana, Erica Racchetti, Fabio Vincenzi, Elisa Anna Fano, Marco Bartoli Within irrigated agricultural watersheds, canal networks may play a crucial role as nitrogen (N) sink. This is due to the intertwined action of macrophytes and microbial communities occurring in the dense net of small watercourses. We hypothesize that vegetated canals may buffer relevant fractions of excess N from agriculture via microbial denitrification, and that vegetation provides multiple interfaces that greatly support the activity of bacteria. To test these hypotheses, we measured net dinitrogen (N2) fluxes in bare sediments and at the reach-scale in vegetated ditches. As study areas we selected canals subjected to diffuse N pollution, laying in a lowland sub-basin of the Po River (northern Italy). Denitrification was evaluated on the basis of changes in dissolved N2:Ar, measured by Membrane Inlet Mass Spectrometry. Complementary data were obtained via upstream–downstream inorganic N balances and intact core incubations targeting sedimentary N fluxes. Denitrification was the major pathway for N removal, with rates at the reach-scale (5–25mmolNm−2 d−1) up to one order of magnitude higher than in sediment alone (3–7mmolNm−2 d−1). Results highlighted that N uptake by macrophyte stands was quantitatively small; however, aquatic vegetation provided multiple interfaces for microbial growth and N-related processes. Our data suggest that 1ha of vegetated canal may remove between 150 and 560kgNyr−1. In the study area, an average canal density of ∼0.05 linear kmha−1 of agricultural land has the potential to buffer 5–17% of the excess N from agriculture (∼60kgNha−1 yr−1). The results of this study suggest the central role of emergent vegetation in promoting microbial N-transformation and canal self-depuration. Innovative management of the canal networks should couple hydraulic needs with the maintenance of emergent vegetation. Graphical abstract
Print ISSN: 0167-8809
Electronic ISSN: 1873-2305
Kategorien: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Published by Elsevier
5.
PAPER CURRENT
Development of a cell-based screening method for compounds that inhibit or are transported by large neutral amino acid transporter 1, a key transporter at the blood–brain barrier (2015)
Elsevier
Publication Date: 2015-08-03
Description: Publication date: 1 October 2015 Source:Analytical Biochemistry, Volume 486 Author(s): Jian Chen, Lili Liang, Yumin Liu, Li Zhang Large neutral amino acid transporter 1 (LAT1) transports neutral amino acids with aromatic or branched side chains as well as their derivatives or prodrugs. Because the transporter is highly expressed at the blood–brain barrier and in some tumor cells, it is a potential target to treat brain disease and cancer. Therefore, it is essential to develop a method to screen for LAT1 inhibitors or for therapeutic compounds that it can transport. In this study, one such method was developed that combines an in vitro cell-based assay with high-throughput ultra-performance liquid chromatography triple quadrupole mass spectrometry (UPLC–QQQ–MS). Using this method, candidate compounds could be tested for the ability to inhibit or to compete with uptake of gabapentin, an LAT1 substrate, in HT-29 cells, which abundantly express the transporter. Gabapentin uptake is measured by mass spectrometry, which requires as little as 6min/sample and will enable analysis of large numbers of samples. We anticipate that the method will be useful to identify LAT1 inhibitors or substrates without the need for animals or radioactive labeling.
Print ISSN: 0003-2697
Electronic ISSN: 1096-0309
Kategorien: Biology , Chemistry and Pharmacology
Published by Elsevier
6.
PAPER CURRENT
Legislative correlates of the size and number of protected areas in Canadian jurisdictions (2015)
Elsevier
Publication Date: 2015-08-03
Description: Publication date: November 2015 Source:Biological Conservation, Volume 191 Author(s): Shawn J. Leroux, Chris Brimacombe, Shahira Khair, Jamie Benidickson, C. Scott Findlay Protected area legislation provides the statutory authority for the establishment and management of protected areas. Yet few studies have investigated the relationship between protected area legislation and those attributes of protected areas that are likely to affect their success in achieving biodiversity conservation objectives. Here we investigate the association between the size and number of protected areas within Canadian provincial, territorial and federal jurisdictions and provisions of the corresponding legislation using a Before–After/Control–Impact design. We found that jurisdictions with legislation that includes explicit provisions for donations in cash or in-kind and many types of stakeholder involvement had, on average, larger (1.01× to 29.0×) protected areas after versus before legislation enactment, compared to those without such provisions. Jurisdictions with legislation that includes provisions for protected area co-management with local or aboriginal/indigenous communities also had, on average, a higher rate of park establishment after (0.17–23.7 protected areas/year) versus before (0.17–6.34 protected areas/year) legislation enactment, compared to those without such provisions (0.09–5.00 protected areas/year; 0.21–5.30 protected areas/year after and before respectively). Similar patterns were detected for jurisdictions with legislation that includes provisions for operating and/or capital cost recovery. Our results suggest that legislative provisions that facilitate stakeholder participation and cost recovery may contribute to the establishment of more and larger protected areas. As signatories to the Convention on Biological Diversity attempt to expand protected area networks, they should consider including provisions concerning stakeholder involvement and cost recovery into protected areas legislation.
Print ISSN: 0006-3207
Kategorien: Biology
Published by Elsevier
7.
PAPER CURRENT
Liquid and plastic limits of mountain soils as a function of the soil and horizon type (2015)
Elsevier
Publication Date: 2015-08-03
Description: Publication date: December 2015 Source:CATENA, Volume 135 Author(s): S. Stanchi, M. D'Amico, E. Zanini, M. Freppaz Soil degradation by processes such as soil erosion, shallow landslides, debris-flows etc. is a significant problem in mountain areas, and is a crucial issue for natural hazard assessment in mountain areas. Several soil properties, among which are the liquid and plastic limits, i.e. moisture contents for which a soil passes from the plastic to liquid state (liquid limit, LL) and from the semisolid to plastic state (PL, plastic limit), have been proposed as indicators for soil vulnerability to degradation processes, both of natural and anthropogenic origin. In this research we investigated the liquid and plastic limits of the main soil groups of World Reference Base for Soil Resources (WRB) classification present in Aosta Valley (N–W Italian Alps) from a pedogenic perspective. In particular, we compared 1) soils at different stages of development; and 2) different genetic horizons. Our main aim was to provide and interpret data on soils' consistency and mechanical behavior that may be used as indexes for the assessment of soil vulnerability. Despite its relatively small area, the Aosta Valley is characterized by a wide range of soil types. Sixty-two soils with different profile evolution stages, representative of 7 WRB soil groups, were investigated and LL and PL in genetic horizons were studied at the soil type and genetic horizons level. In general, soil consistency was largely determined by the organic matter content (both in topsoils and organic matter-enriched subsurface horizons), but in spodic horizons and some C horizons a role of poorly crystalline and pedogenic iron oxides was observed too. Considering the vulnerability to consistency loss, that can result in erosion processes and overall soil degradation, surface horizons were generally less vulnerable, as could be expected on the basis of previous research, i.e. showed higher LL and PL values, than the deeper ones, generally characterized by a reduction of soil consistency. Therefore, topsoil could receive higher water inputs while still preserving their consistency and strength. This was not confirmed in Podzols, where the organic matter enrichment of spodic horizons determined a discontinuity in physical properties between the E horizons (more vulnerable) and the underlying, spodic ones. The same trend was observed for Calcisols with a deep cemented Bkm horizon. The research provided a novel overview on LL and PL in the common soil types present in the Alpine region, integrating the already existing research on topsoil vulnerability to degradation processes (erosion, consistency losses, losses of strength), and the regional soil database. The use of LL and PL as indicators of soil physical quality was approached with a pedogenic perspective, which might be helpful for a better definition of hazard assessment at the regional scale.
Print ISSN: 0341-8162
Electronic ISSN: 1872-6887
Kategorien: Geography , Geosciences
Published by Elsevier
8.
PAPER CURRENT
Micro-hydration and acid dissociation mechanism of B(OH)3 (2015)
Elsevier
Publication Date: 2015-08-03
Description: Publication date: 1 September 2015 Source:Chemical Physics Letters, Volume 636 Author(s): Yongquan Zhou, Yan Fang, Chunhui Fang, Fayan Zhu, Haiwen Ge, Hongyan Liu As a Lewis weak acid, the hydration and acid dissociation mechanisms of B(OH)3 are still unclear. In present letter, we calculated the optimized structure, stability and Raman spectra for micro-hydrated clusters of B(OH)3 with DFT in both gaseous and aqueous phase at B3LYP/aug-cc-pVDZ level. The stepwise micro-hydration process of B(OH)3 were described in detailed. The micro-hydration process and Raman spectrum study indicate that the axial hydration is a “trigger” for B(OH)3 dissociation. Graphical abstract
Print ISSN: 0009-2614
Electronic ISSN: 1873-4448
Kategorien: Chemistry and Pharmacology , Physics
Published by Elsevier
9.
PAPER CURRENT
Patterns of rare earth and other trace elements in Paleogene and Miocene clayey sediments from the Mondego platform (Central Portugal) (2015)
Elsevier
Publication Date: 2015-08-03
Description: Publication date: Available online 1 August 2015 Source:Chemie der Erde - Geochemistry Author(s): J.V. Lisboa, D.P.S. de Oliveira, F. Rocha, A. Oliveira, J. Carvalho In the present study the origin of clay deposits occurring in an inland platform, in central Portugal, was investigated by their mineralogical and chemical composition. The clay deposits, exploited for ceramic industry are composed of silt-clay facies, the Monteira Member and the Arroça Member, which are assigned to the Coja Formation (Paleogene) and the Campelo Formation (Miocene), respectively. These clayey facies show almost compositional homogeneity, especially concerning texture. The mineralogical composition of the Monteira Member displays slightly higher content in smectite and interstratified clay minerals, which is supported by the chemical composition of samples analyzed. Both members present similar REE patterns, displaying an intense weathering record and little variation in the source area composition. Minor element geochemistry suggests low content in heavy minerals and transition metals. REE patterns and ratios of geochemical parameters support the dominant metasedimentary provenance, with a granite source contribution and also mature recycled sediments of continental origin. The study results’ suggest that the clays of these two members have the same source in terms of lithology and recycled sediments from the Hesperian massif. During the deposition of the Arroça Member, a major remobilization of the Monteira Member is suggested, explaining the geochemical similarity of both facies.
Print ISSN: 0009-2819
Electronic ISSN: 1611-5864
Kategorien: Chemistry and Pharmacology , Geosciences
Published by Elsevier
10.
PAPER CURRENT
Duckweed biomass as a renewable biorefinery feedstock: Ethanol and succinate production from Wolffia globosa (2015)
Elsevier
Publication Date: 2015-08-03
Description: Publication date: October 2015 Source:Biomass and Bioenergy, Volume 81 Author(s): Satoshi Soda, Takeshi Ohchi, Jusakulvijit Piradee, Yuichiro Takai, Michihiko Ike For evaluating duckweed biomass as a bioresource, the specific growth rate and the chemical constituents of duckweed of four kinds were investigated. Spirodela polyrrhiza, Lemna minor, Wolffia arrhiza, and Wolffia globosa commonly showed high specific growth rates of 0.22–0.30 d−1 with initial concentrations of nitrogen >3.0 kg m−3 and phosphorus >5.0 kg m−3. All duckweeds had high sugar contents greater than 300 g kg−1 of dry mass. Especially, vegetative fronds of W. globosa showed the highest sugar content of 410 g kg−1 of dry mass. The duckweed biomass was pretreated easily by heating at 121 °C for saccharification using α-amylase and amyloglucosidase. The ethanol yield of W. globosa biomass in the simultaneous saccharification and fermentation (SSF) using the enzymes and dry yeast was 170 g kg−1 of dry mass, whereas the succinate yield in the SSF using the enzymes and Actinobacillus succinogenes was 200 g kg−1 of dry mass. The production rates of ethanol and succinate from the W. globosa biomass were estimated as 0.58 kg m−2 y−1 and 0.68 kg m−2 y−1, respectively. The biomass of duckweed, with its high growth rate and high starch content, can be an excellent renewable feedstock for the production of ethanol and succinate as building block chemicals for the replacement of petrochemicals. Graphical abstract
Print ISSN: 0961-9534
Kategorien: Energy, Environment Protection, Nuclear Power Engineering , Process Engineering, Biotechnology, Nutrition Technology
Published by Elsevier