239 research outputs found
Carbon Efficiency of Humanitarian Supply Chains: Evidence from French Red Cross operations
Natural catastrophes are often amplified by man-made impact on the environment. Sustainability is identified as a major gap in humanitarian logistics research literature. Although humanitarian supply chains are designed for speed and sustainability is of minor concern, environmentally-friendly behavior (e.g. through reduction of transportation emissions and avoidance of non-degradable materials) should be a long-term concern as it may ultimately affect more vulnerable regions. The purpose of this paper is to illustrate how green house gas emissions can be measured using the supply chain of common relief items in humanitarian logistics. We analyze the CO2 emissions of selected supply chains by performing Life Cycle Assessments based on data provided by the French Red Cross. We calculate the CO2 emissions of the items from âcradle to graveâ including production, transportation, warehousing and disposal. Using these calculations, we show that transporting relief items causes the majority of emissions; however, transportation modes may not always be changed as the main purpose of humanitarian supply chains is speed. Nevertheless, strategic and efficient pre-positioning of main items will translate into less transportation and thus reducing the environmental impact. The study also shows that initiatives for âgreeningâ item production and disposal can improve the overall carbon efficiency of humanitarian supply chains
Influential publications in ecological economics revisited
International audienceWe revisit the analysis of Costanza et al. (2004, Ecological Economics) of influential publications in ecological economics to discover what has changed a decade on. We examine which sources have been influential on the field of ecological economics in the past decade, which articles in the journal Ecological Economics have had the most influence on the field and on the rest of science, and on which areas of science the journal is having the most influence. We find that the field has matured over this period, with articles published in the journal having a greater influence than before, an increase in citation links to environmental studies journals, a reduction in citation links to mainstream economics journals, and possibly a shift in themes to a more applied and empirical direction
World input-output network
Production systems, traditionally analyzed as almost independent national systems, are increasingly connected on a global scale. Only recently becoming available, the World Input-Output Database (WIOD) is one of the first efforts to construct the global multi-regional input-output (GMRIO) tables. By viewing the world input-output system as an interdependent network where the nodes are the individual industries in different economies and the edges are the monetary goods flows between industries, we analyze respectively the global, regional, and local network properties of the so-called world input-output network (WION) and document its evolution over time. At global level, we find that the industries are highly but asymmetrically connected, which implies that micro shocks can lead to macro fluctuations. At regional level, we find that the world production is still operated nationally or at most regionally as the communities detected are either individual economies or geographically well defined regions. Finally, at local level, for each industry we compare the network-based measures with the traditional methods of backward linkages. We find that the network-based measures such as PageRank centrality and community coreness measure can give valuable insights into identifying the key industries
Environment-economy tradeoff for BeijingâTianjinâHebeiâs exports
The trade of goods among regions or nations associated with large environmental consequences. Yet balancing economic gains and environmental consequences induced by trade is still hindered by a lack of quantification of these two factors, especially for the environmental problems those are more locally oriented, such as the atmospheric pollution. Based on an environmental input-output analysis for 2010, we contrast economic gains (value added) against atmospheric pollutant emissions (sulfur dioxide (SO2), nitric oxide (NOx), primary fine particulate matter (PM2.5) and non-methane volatile organic compounds (NMVOC)) and the widely concerned CO2 emissions associated with international and interprovincial exports from Beijing-Tianjin-Hebei (BTH), the most polluted area in China. Our results show that exports contributed 55-62% of BTH's production emissions and 54% of its total value added. BTH's large exports of metals and metal products, nonmetal mineral products, chemical and transportation and warehousing, generated a larger share of pollutant emissions (36-46% of BTH's total) than that of value added (17%) along the supply chain. Most of BTH's embodied emissions in exports go to neighboring provinces and the developed east coastal regions in China, although the economic returns are comparatively low. Among BTH, industrial production in Beijing and Tianjin lead to more pollutant emission than value added in Hebei, due to reliance on pollution-intensive product imports from Hebei. Our results call for refocusing and restructuring of BTH's industry and trade structures to balance the economic gains and environmental losses for each region
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Thermopower across the phase diagram of the cuprate La1.6âxNd0.4SrxCuO4 : signatures of the pseudogap and charge-density-wave phases
The Seebeck coeïŹcient (thermopower) S of the cuprate superconductor La1.6âxNd0.4SrxCuO4
was measured across its doping phase diagram (from p = 0.12 to p = 0.25), at various temperatures
down to T â 2 K, in the normal state accessed by suppressing superconductivity with a magnetic
ïŹeld up to H = 37.5 T. The magnitude of S/T in the T = 0 limit is found to suddenly increase,
by a factor â 5, when the doping is reduced below p
â = 0.23, the critical doping for the onset
of the pseudogap phase. This conïŹrms that the pseudogap phase causes a large reduction of the
carrier density n, consistent with a drop from n = 1 + p above p
â to n = p below pâ, as previously
inferred from measurements of the Hall coeïŹcient, resistivity and thermal conductivity. When the
doping is reduced below p = 0.19, a qualitative change is observed whereby S/T decreases as T â 0,
eventually to reach negative values at T = 0. In prior work on other cuprates, negative values of
S/T at T â 0 were shown to result from a reconstruction of the Fermi surface caused by charge-
density-wave (CDW) order. We therefore identify pCDW â 0.19 as the critical doping beyond which
there is no CDW-induced Fermi surface reconstruction. The fact that pCDW is well separated from
p
â reveals that there is a doping range below pâ where the transport signatures of the pseudogap
phase are unaïŹected by CDW correlations, as previously found in YBa2Cu3Oy and La2âxSrxCuO4.Center for Dynamics and Control of Material
The CCR4-NOT Complex Physically and Functionally Interacts with TRAMP and the Nuclear Exosome
BACKGROUND: Ccr4-Not is a highly conserved multi-protein complex consisting in yeast of 9 subunits, including Not5 and the major yeast deadenylase Ccr4. It has been connected functionally in the nucleus to transcription by RNA polymerase II and in the cytoplasm to mRNA degradation. However, there has been no evidence so far that this complex is important for RNA degradation in the nucleus. METHODOLOGY/PRINCIPAL FINDINGS: In this work we point to a new role for the Ccr4-Not complex in nuclear RNA metabolism. We determine the importance of the Ccr4-Not complex for the levels of non-coding nuclear RNAs, such as mis-processed and polyadenylated snoRNAs, whose turnover depends upon the nuclear exosome and TRAMP. Consistently, mutation of both the Ccr4-Not complex and the nuclear exosome results in synthetic slow growth phenotypes. We demonstrate physical interactions between the Ccr4-Not complex and the exosome. First, Not5 co-purifies with the exosome. Second, several exosome subunits co-purify with the Ccr4-Not complex. Third, the Ccr4-Not complex is important for the integrity of large exosome-containing complexes. Finally, we reveal a connection between the Ccr4-Not complex and TRAMP through the association of the Mtr4 helicase with the Ccr4-Not complex and the importance of specific subunits of Ccr4-Not for the association of Mtr4 with the nuclear exosome subunit Rrp6. CONCLUSIONS/SIGNIFICANCE: We propose a model in which the Ccr4-Not complex may provide a platform contributing to dynamic interactions between the nuclear exosome and its co-factor TRAMP. Our findings connect for the first time the different players involved in nuclear and cytoplasmic RNA degradation
Interactions between selected bile salts and Triton X-100 or sodium lauryl ether sulfate
<p>Abstract</p> <p>Background</p> <p>In order to develop colloidal drug carriers with desired properties, it is important to determine physico-chemical characteristics of these systems. Bile salt mixed micelles are extensively studied as novel drug delivery systems. The objective of the present investigation is to develop and characterize mixed micelles of nonionic (Triton X-100) or anionic (sodium lauryl ether sulfate) surfactant having oxyethylene groups in the polar head and following bile salts: cholate, deoxycholate and 7-oxodeoxycholate.</p> <p>Results</p> <p>The micellization behaviour of binary anionic-nonionic and anionic-anionic surfactant mixtures was investigated by conductivity and surface tension measurements. The results of the study have been analyzed using Clint's, Rubingh's, and Motomura's theories for mixed binary systems. The negative values of the interaction parameter indicate synergism between micelle building units. It was noticed that Triton X-100 and sodium lauryl ether sulfate generate the weakest synergistic interactions with sodium deoxycholate, while 7-oxodeoxycholate creates the strongest attractive interaction with investigated co-surfactants.</p> <p>Conclusion</p> <p>It was concluded that increased synergistic interactions can be attributed to the larger number of hydrophilic groups at α side of the bile salts. Additionally, 7-oxo group of 7-oxodeoxycholate enhance attractive interactions with selected co-surfactants more than 7-hydroxyl group of sodium cholate.</p
Domain Organization of Long Signal Peptides of Single-Pass Integral Membrane Proteins Reveals Multiple Functional Capacity
Targeting signals direct proteins to their extra - or intracellular destination such as the plasma membrane or cellular organelles. Here we investigated the structure and function of exceptionally long signal peptides encompassing at least 40 amino acid residues. We discovered a two-domain organization (âNtraC modelâ) in many long signals from vertebrate precursor proteins. Accordingly, long signal peptides may contain an N-terminal domain (N-domain) and a C-terminal domain (C-domain) with different signal or targeting capabilities, separable by a presumably turn-rich transition area (tra). Individual domain functions were probed by cellular targeting experiments with fusion proteins containing parts of the long signal peptide of human membrane protein shrew-1 and secreted alkaline phosphatase as a reporter protein. As predicted, the N-domain of the fusion protein alone was shown to act as a mitochondrial targeting signal, whereas the C-domain alone functions as an export signal. Selective disruption of the transition area in the signal peptide impairs the export efficiency of the reporter protein. Altogether, the results of cellular targeting studies provide a proof-of-principle for our NtraC model and highlight the particular functional importance of the predicted transition area, which critically affects the rate of protein export. In conclusion, the NtraC approach enables the systematic detection and prediction of cryptic targeting signals present in one coherent sequence, and provides a structurally motivated basis for decoding the functional complexity of long protein targeting signals
Marine fish traits follow fast-slow continuum across oceans
A fundamental challenge in ecology is to understand why species are found where they are and predict
where they are likely to occur in the future. Trait-based approaches may provide such understanding,
because it is the traits and adaptations of species that determine which environments they can inhabit.
It is therefore important to identify key traits that determine species distributions and investigate
how these traits relate to the environment. Based on scientific bottom-trawl surveys of marine fish
abundances and traits of >1,200 species, we investigate trait-environment relationships and project
the trait composition of marine fish communities across the continental shelf seas of the Northern
hemisphere. We show that traits related to growth, maturation and lifespan respond most strongly to
the environment. This is reflected by a pronounced âfast-slow continuumâ of fish life-histories, revealing
that traits vary with temperature at large spatial scales, but also with depth and seasonality at more
local scales. Our findings provide insight into the structure of marine fish communities and suggest that
global warming will favour an expansion of fast-living species. Knowledge of the global and local drivers
of trait distributions can thus be used to predict future responses of fish communities to environmental
change.Postprint2,92
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