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JEANETTE WHITAKER KATHERINE E. LUDLEY REBECCA ROWE GAIL TAYLOR DAVID C. HOWARD 《Global Change Biology Bioenergy》2010,2(3):99-112
Across the energy sector, alternatives to fossil fuels are being developed, in response to the dual drivers of climate change and energy security. For transport, biofuels have the greatest potential to replace fossil fuels in the short‐to medium term. However, the ecological benefits of biofuels and the role that their deployment can play in mitigating climate change are being called into question. Life Cycle Assessment (LCA) is a widely used approach that enables the energy and greenhouse gas (GHG) balance of biofuel production to be calculated. Concerns have nevertheless been raised that published data show widely varying and sometimes contradictory results. This review describes a systematic review of GHG emissions and energy balance data from 44 LCA studies of first‐ and second‐generation biofuels. The information collated was used to identify the dominant sources of GHG emissions and energy requirements in biofuel production and the key sources of variability in published LCA data. Our analysis revealed three distinct sources of variation: (1) ‘real’ variability in parameters e.g. cultivation; (2) ‘methodological’ variability due to the implementation of the LCA method; and (3) ‘uncertainty’ due to parameters rarely included and poorly quantified. There is global interest in developing a sustainability assessment protocol for biofuels. Confidence in the results of such an assessment can only be assured if these areas of uncertainty and variability are addressed. A more defined methodology is necessary in order to allow effective and accurate comparison of results. It is also essential that areas of uncertainty such as impacts on soil carbon stocks and fluxes are included in LCA assessments, and that further research is conducted to enable a robust calculation of impacts under different land‐use change scenarios. Without the inclusion of these parameters, we cannot be certain that biofuels are really delivering GHG savings compared with fossil fuels. 相似文献
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REBECCA CASSIDY 《The journal of the Royal Anthropological Institute》2012,18(2):266-284
Changes in regulation and taxation during the past decade have had a profound effect on the experience of betting in dedicated shops in the United Kingdom. This article explores how betting shop customers and staff in London have responded to the introduction of gambling machines depicting roulette and other casino‐type games in an environment that was traditionally dedicated to betting on horse and dog racing. The rise of machine gambling has been presented as a transition from ‘social’ to ‘asocial’ forms of gambling by researchers working in the UK, Las Vegas, and Australia. Traditional bettors and betting shop staff also present betting and machine play as discrete and value them differently. I show that while some of the experiential qualities of machine play observed elsewhere have been replicated in shops, the differences between traditional betting and machine play are overstated, for structural reasons. Traditional bettors and staff are interested in distinguishing their activities from those of newcomers. Responses to new gambling media in betting shops are socially, as well as experientially, mediated, a crucial insight for the wider study of gambling and gambling regulation.
Résumé
L'évolution de la réglementation et de la taxation des paris a eu depuis une dizaine d'année de profonds effets sur l'expérience des parieurs dans les officines du Royaume‐Uni. Le présent article étudie la réaction des clients et du personnel de bureaux de paris londoniens à l'apparition des machines proposant des jeux de roulette et autres jeux de casino dans un environnement traditionnellement dévolu aux paris sur les courses de chevaux et de chiens. Au Royaume‐Uni, à Las Vegas et en Australie, des chercheurs ont présenté l'essor des machines de jeux comme le passage de formes de jeu « sociales »à d'autres « asociales ». Les parieurs traditionnels et les employés des bureaux de paris considèrent eux aussi les paris et les jeux sur machines comme deux activités distinctes et de valeur différente. L'auteure montre ici qu'une partie des qualités de l'expérience du jeu sur machines observées ailleurs se retrouvent dans les bureaux de paris, mais que les auteurs ont exagéré les différences entre paris traditionnels et jeux sur machines, pour des raisons structurelles. Les parieurs traditionnels et les employés ont intérêt à distinguer leurs activités de celles des nouveaux venus. La réponse aux nouveaux modes de jeu dans les bureaux de paris, médiée socialement mais aussi par l'expérience, est très instructive pour l'étude plus large des jeux de paris et de leur réglementation. 相似文献144.
SUJAL S. PHADKE REBECCA A. ZUFALL 《Biological journal of the Linnean Society. Linnean Society of London》2009,98(1):187-197
Ciliates are a diverse group of microbial eukaryotes that exhibit tremendous variety in several aspects of their mating systems. To understand the evolutionary forces driving mating system diversification in ciliates, we use a comparative approach synthesizing data from many ciliate species in light of recent phylogenetic analyses. Specifically, we investigate the evolution of number of mating types, mode of mating type inheritance, and the molecular determinants of mating types across the taxonomic diversity of ciliates, with an emphasis on three well-studied genera: Tetrahymena , Paramecium , and Euplotes . We find that there have been many transitions in the number of mating types, and that the requirement of nuclear reorganization may be a more important factor than genetic exchange in determining the optimum number of mating types in a species. We also find that the molecular determinants of mating types and mode of inheritance are evolving under different constraints in different lineages of ciliates. Our results emphasize the need for further detailed examination of mating systems in understudied ciliate lineages. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society , 2009, 98 , 187–197. 相似文献
145.
POWERS DENNIS A.; ROPSON IRA; BROWN DREW C.; van BENEDEN REBECCA; CASHON ROBERT; GONZALEZ-VILLASENOR LUCIA IRENE; DIMICHELE JUDITH A. 《Integrative and comparative biology》1986,26(1):131-144
Studies of 16 polymorphic loci in the fish Fundulus heteroclitushave uncovered significant directional changes in gene frequencieswith latitude (i.e., clines). These spatial patterns could havearisen by primary and/or secondary intergradation. While wecannot presently distinguish between these two models, mitochondrialDNA analyses indicate that if previous isolation occurred asrequired for secondary intergradation, it must have been relativelyrecent and of short duration. Herein we discuss the roles ofgenetic drift, random migration, nonrandom migration, selectionand others as potential driving forces for both modes of clineformation. In addition, we address the potential role of thelast glacial period in (1) creating isolating barriers, (2)the opening of unoccupied habitats for range extension, and(3) as a mechanism for thermal selection. While some evidenceexists that at least one of the driving forces is selection,the extent to which it and other deterministic forces participateas opposed to various stochastic processes must await furtheranalysis 相似文献
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REBECCA L. BOULTON JULIE L. LOCKWOOD MICHELLE J. DAVIS ARTUR PEDZIWILK KELLY A. BOADWAY JOSHUA J. T. BOADWAY DAVID OKINES STUART L. PIMM 《The Journal of wildlife management》2009,73(4):530-537
ABSTRACT We investigated survival for male, female, and first-year Cape Sable seaside sparrows (Ammodramus maritimus mirabilis, hereafter sparrows), a federally endangered bird restricted to the Florida Everglades, USA. Accurate estimates of survival are critical to improve management decisions and population estimates for this and other threatened species. We used Program MARK to evaluate effects of age, sex, population membership, temporal variation, and ground-water levels on annual survival from mark-recapture data collected across 3 sparrow populations from 1997 to 2007. We found little evidence that annual survival rates differed between the populations or across ground-water levels, but we found high variability between years for both adult and juvenile survival. Our results revealed female sparrows experienced 14–19% lower survival than males. Sparrows experienced much lower survival during their first year of life and were short-lived (2–3 yr). Our results highlight sparrows' susceptibility to population declines and suggest that management actions aimed at increasing survival may be effective for this species' management. 相似文献
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