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371.
Measuring the welfare cost of climate change policies is a real challenge, raising difficult issues of micro- and macro-economics: cost-benefit analysis on the one hand, foreign trade and international specialization on the second hand. At the domestic level the possible existence of distortions, in particular in the fiscal system, may either increase or alleviate the welfare cost of a climate change policy, as illustrated by the debate on double dividend. Effects on the prices in international markets and distorted competition between countries committed to abate (Annex B) and uncommitted countries affect both the sharing of the burden, in particular through the change in the terms of trade, and the allocation of activities with the frequently waved threat of delocalization. Based on a companion theoretical analysis, the present paper aims at putting order in the welfare analysis of climate change policy and to present and compare various estimations, issuing from macro- or computable general equilibrium models. Beside the global welfare cost, the paper focuses on the marginal abatement cost and its relation to the carbon price.Most present conceptual and applied analysis is based on the case of a single domestic household-consumer. Taking into account several consumers raises new challenges, concerning equity but even more fundamentally the mere definition of fiscal distortion, which have not yet been really addressed. 相似文献
372.
Pitchford ML Schichtel BA Gebhart KA Barna MG Malm WC Tombach IH Knipping EM 《Journal of the Air & Waste Management Association (1995)》2005,55(11):1726-1732
The recently completed Big Bend Regional Aerosol and Visibility Observational (BRAVO) Study focused on particulate sulfate source attribution for a 4-month period from July through October 1999. A companion paper in this issue by Schichtel et al. describes the methods evaluation and results reconciliation of the BRAVO Study sulfate attribution approaches. This paper summarizes the BRAVO Study extinction budget assessment and interprets the attribution results in the context of annual and multiyear causes of haze by drawing on long-term aerosol monitoring data and regional transport climatology, as well as results from other investigations. Particulate sulfates, organic carbon, and coarse mass are responsible for most of the haze at Big Bend National Park, whereas fine particles composed of light-absorbing carbon, fine soils, and nitrates are relatively minor contributors. Spring and late summer through fall are the two periods of high-haze levels at Big Bend. Particulate sulfate and carbonaceous compounds contribute in a similar magnitude to the spring haze period, whereas sulfates are the primary cause of haze during the late summer and fall period. Atmospheric transport patterns to Big Bend vary throughout the year, resulting in a seasonal cycle of different upwind source regions contributing to its haze levels. Important sources and source regions for haze at Big Bend include biomass smoke from Mexico and Central America in the spring and African dust during the summer. Sources of sulfur dioxide (SO2) emissions in Mexico, Texas, and in the Eastern United States all contribute to Big Bend haze in varying amounts over different times of the year, with a higher contribution from Mexican sources in the spring and early summer, and a higher contribution from U.S. sources during late summer and fall. Some multiple-day haze episodes result from the influence of several source regions, whereas others are primarily because of emissions from a single source region. 相似文献
373.
These days, corporate annual reports are full of references to shareholder wealth creation. In today's highly competitive capital markets, most chief executives understand that unless they are seen as value creators, investors will place their scarce capital somewhere else. Clear evidence of the growing importance, even dominance, of shareholder wealth creation is the growing use of a performance measure known as economic value added (EVA®).1 Within ten years, it is almost certain that most large, publicly traded companies in the United States will be using EVA or something like it as a primary performance evaluation tool. Recently, many non-American companies have also adopted it to better align the incentives of managers with shareholders and to signal their commitment to value creation. EVA is not widely known or understood among environmental specialists, and those who have heard about it often fear it. We find this attitude unfortunate. In this article, we discuss EVA and how its use can aid corporate environmental managers in promoting more proactive environmental investments, and in funding capital investments on environmental improvement, waste reduction, and pollution control in their companies. The use of EVA and other shareholder value measures can also improve general capital investment decisions by integrating environmental factors that affect the long-term interests of the corporation into the managerial decision-making process. 相似文献
374.
Thirty-two pregnancies (11 primi- and 21 multi-gravid) with an abnormal fetus were terminated between 16 and 35 weeks (mean 22 weeks; median 20 weeks) and a continuous intravenous infusion of 1 μg of the prostaglandin analogue sulprostone. All pregnancies were terminated vaginally, 31 of them with this regimen in a median induction-expulsion interval of 23 h (range 8–52 h). Complete expulsion of the placenta occurred in 72 per cent of cases. Median blood loss was 100 ml (range 20–2000 ml). There were only a few side-effects. We conclude that this induction regimen is both appropriate and safe for pregnancy termination in cases of fetal anomaly. 相似文献
375.
ter Hofstede HM Goerlitz HR Montealegre-Z F Robert D Holderied MW 《Die Naturwissenschaften》2011,98(12):1057-1061
Ears evolved in many groups of moths to detect the echolocation calls of predatory bats. Although the neurophysiology of bat
detection has been intensively studied in moths for decades, the relationship between sound-induced movement of the noctuid
tympanic membrane and action potentials in the auditory sensory cells (A1 and A2) has received little attention. Using laser
Doppler vibrometry, we measured the velocity and displacement of the tympanum in response to pure tone pulses for moths that
were intact or prepared for neural recording. When recording from the auditory nerve, the displacement of the tympanum at
the neural threshold remained constant across frequencies, whereas velocity varied with frequency. This suggests that the
key biophysical parameter for triggering action potentials in the sensory cells of noctuid moths is tympanum displacement,
not velocity. The validity of studies on the neurophysiology of moth hearing rests on the assumption that the dissection and
recording procedures do not affect the biomechanics of the ear. There were no consistent differences in tympanal velocity
or displacement when moths were intact or prepared for neural recordings for sound levels close to neural threshold, indicating
that this and other neurophysiological studies provide good estimates of what intact moths hear at threshold. 相似文献
376.
Doug M. Boyer Guntupalli V. R. Prasad David W. Krause Marc Godinot Anjali Goswami Omkar Verma John J. Flynn 《Die Naturwissenschaften》2010,97(4):365-377
Extant species of the supraordinal mammal clade Euarchonta belong to the orders Primates, Scandentia, or Dermoptera. The fossil
record of euarchontans suggests that they underwent their initial radiation during the Paleocene (65–55 million years ago)
in North America, Eurasia, and Africa. The time and place of origin is poorly resolved due to lack of definitive fossils of
euarchontan stem taxa. We describe a fragmentary humerus and two fragmentary ulnae from the latest Cretaceous of India that
bear significantly on this issue. The fossils are tentatively referred to Deccanolestes cf. hislopi due to their small size and the fact that Deccanolestes is the only eutherian dental taxon to have been recovered from the same locality. The new fossils are used to evaluate the
existing behavioral hypothesis that Deccanolestes was arboreal, and the competing phylogenetic hypotheses that Deccanolestes is a stem eutherian versus a stem euarchontan. The humerus resembles those of euarchontans in possessing a laterally keeled
ulnar trochlea, a distinct zona conoidea, and a spherical capitulum. These features also suggest an arboreal lifestyle. The
ulnar morphology is consistent with that of the humerus in reflecting an arboreal/scansorial animal. Detailed quantitative
comparisons indicate that, despite morphological correlates to euarchontan-like arboreality, the humerus of Deccanolestes is morphologically intermediate between those of Cretaceous “condylarthran” mammals and definitive Cenozoic euarchontans.
Additionally, humeri attributed to adapisoriculids are morphologically intermediate between those of Deccanolestes and definitive euarchontans. If adapisoriculids are euarchontans, as recently proposed, our results suggest that Deccanolestes is more basal. The tentative identification of Deccanolestes as a basal stem euarchontan suggests that (1) Placentalia began to diversify and Euarchonta originated before the Cretaceous–Tertiary
boundary and (2) the Indian subcontinent, Eurasia, and Africa are more likely places of origin for Euarchonta than is North
America. 相似文献
377.
Richard D. Horan Marc O. Ribaudo 《Journal of the American Water Resources Association》1999,35(5):1023-1035
In this paper, we review the physical characteristics of agricultural non point pollution and discuss the implications for setting appropriate pollution control objectives and designing incentive-based pollution control policies. First, we discuss that policy objectives must be designed carefully to ensure positive economic net benefits can be expected from pollution control. Next, we review several classes of incentives and recommend the use of design-based incentives (i.e., incentives based on variable input use, management practices, and land use) for controlling non point pollution. Cost-effectiveness requires that incentives elicit three types of responses from farmers: (1) use variable inputs at appropriate levels, (2) adopt appropriate management practices, and (3) make appropriate land use decisions at the extensive margin of production. If a set of incentives fails to induce the correct responses, the resulting runoff levels and hence ambient pollution levels and damages will be too large relative to policy goals. A review of existing programs suggests that greater program coordination and improved targeting of incentives are needed for further water quality improvements. Alternatively, properly designed market-based systems may be effective alternatives. These systems would reduce overall pollution control costs by allowing markets to allocate point source and non point source control costs more efficiently. 相似文献
378.
Marc Slattery 《Chemoecology》1999,9(3):97-104
Summary. Fungal pathogenesis of the sea fan Gorgonia ventalina has developed on the Belize barrier reef during 1997 and 1998. The disease incidence (= percent of infected sea fans) remained
unchanged at two sites along the barrier reef crest between years. However, the incidence increased significantly at an offshore
atoll during that time, as did the virulence (= percent tissue loss). Grazing by the gorgonian specialist mollusc Cyphoma gibbosum increased on infected sea fans. Sea fan responses to fungal infection included significant decreases in a furano-germacrene
compound with antifeedant activity and significant increases in the concentration of sclerites at the site of infection. Feeding
assays utilizing C. gibbosum and a natural assemblage of reef fishes indicated sclerites are an effective deterrent, to both consumers, at both pre- and
post-infected concentrations. In contrast, the compound was only deterrent to the fish, and only at concentrations found in
pre-infected sea fans. These data indicate that sea fan pathogenesis can directly and indirectly affect population health
via virulent tissue necrosis and pathogen-mediated reductions in grazer resistance, respectively.
Received 4 November 1998; accepted 5 April 1999. 相似文献
379.
Consequences of dominance: a review of evenness effects on local and regional ecosystem processes 总被引:8,自引:0,他引:8
The composition of communities is strongly altered by anthropogenic manipulations of biogeochemical cycles, abiotic conditions, and trophic structure in all major ecosystems. Whereas the effects of species loss on ecosystem processes have received broad attention, the consequences of altered species dominance for emergent properties of communities and ecosystems are poorly investigated. Here we propose a framework guiding our understanding of how dominance affects species interactions within communities, processes within ecosystems, and dynamics on regional scales. Dominance (or the complementary term, evenness) reflects the distribution of traits in a community, which in turn affects the strength and sign of both intraspecifc and interspecific interactions. Consequently, dominance also mediates the effect of such interactions on species coexistence. We review the evidence for the fact that dominance directly affects ecosystem functions such as process rates via species identity (the dominant trait) and evenness (the frequency distribution of traits), and indirectly alters the relationship between process rates and species richness. Dominance also influences the temporal and spatial variability of aggregate community properties and compositional stability (invasibility). Finally, we propose that dominance affects regional species coexistence by altering metacommunity dynamics. Local dominance leads to high beta diversity, and rare species can persist because of source-sink dynamics, but anthropogenically induced environmental changes result in regional dominance and low beta diversity, reducing regional coexistence. Given the rapid anthropogenic alterations of dominance in many ecosystems and the strong implications of these changes, dominance should be considered explicitly in the analysis of consequences of altered biodiversity. 相似文献
380.
Carolina Giraldo Patrick Mayzaud Eric Tavernier Jean-Olivier Irisson Florian Penot Jonathan Becciu Amélie Chartier Marc Boutoute Philippe Koubbi 《Marine Biology》2013,160(4):877-887
Pleuragramma antarcticum is a key component of the neritic assemblages in the Antarctic coastal waters. Larvae of this species were sampled from 2008 to 2011 in the Dumont d’Urville Sea (East Antarctica). The lipid class composition [triacylglycerols (TAG), cholesterol (Chol) and polar lipids (PL)] of larvae was measured to assess the larval condition. The total amount of lipids was linearly related to the quantity of structural polar lipids, suggesting that growth is favored over lipid storage. The TAG:Chol ratio showed interannual variability in the condition of fish larvae, probably related to prey availability. Nevertheless, the essential fatty acids composition of polar lipids illustrates that larvae with low levels of TAG:Chol could be either growing or under starvation. Only the combination of a low TAG:Chol ratio and low polar lipids content, which can also be mobilized during starvation periods, allowed identification of larvae in poor condition. This lipid condition index should be of great assistance to evaluate the probability of survival of P. antarcticum larvae in long-term monitoring. It has widespread applicability and should also be useful in the diagnosis of nutritional condition in other species. 相似文献