102,010 research outputs found
Retracted. X-ray observations of PSR B0355+54 and its pulsar wind nebula (Astrophysics and Space Science, (2007), 308, 1-4, (309-316), 10.1007/s10509-007-9319-9)
No full textRetraction Note to: Astrophys. Space. Sci. (2007) 308: 309–316https://doi.org/10.1007/s10509-007-9319-9 The authors have retracted this article (McGowan et al. 2007) which was unintentionally submitted in full length as part of a conference proceedings. However, the authors had already published the article in another journal (McGowan et al. 2006). Therefore this article is redundant. All authors agree with this retraction.Paper was orginally published as K. E. McGowan, W. T. Vestrand, J. A. Kennea, S. Zane, M. Cropper, and F. A. Córdova (2006) 'Probing the Pulsar Wind Nebula of PSR B0355+54', The Astrophysical Journal, 647, 1300, 10.1086/505522</p
Options for Energy Efficiency in India and Barriers to Their Adoption: A Scoping Study
No full textWe review the economics literature on energy efficiency in India, as a guide for further research in the area. The empirical literature has focused on four questions: How does energy efficiency in India compare with energy efficiency in other countries? What would be the energy savings (and cost savings) from adopting certain energy-efficient technologies? Why are these technologies being -- or not being -- adopted? What policies should be implemented to encourage their adoption? Most of the literature focuses on answers to the first two questions. Studies are needed that quantify factors affecting the rate of diffusion of energy-efficient technologies and rigorously evaluate reforms implemented by the Government of India, beginning in the 1990s, that could affect energy efficiency.energy efficiency, energy use, India
Letter, [Author unclear] to Paulina T. Merritt
No full textHandwritten letter to Paulina Merritt from an unknown author, October 1, 1876.
The isolated neutron star X-ray pulsars RX J0420.0–5022 and RX J0806.4–4123 : new X-ray and optical observations
No full textWe report on the analysis of new X-ray data obtained with XMM-Newton and Chandra from two ROSAT-discovered X-ray dim isolated neutron stars (XDINs). RX J0806.4−4123 was observed with XMM-Newton in April 2003, 2.5 years after
the first observation. The EPIC-pn data confirm that this object is an X-ray pulsar with 11.371 s neutron star spin period. The X-ray spectrum is consistent with absorbed black-body emission with a temperature kT = 96 eV and N H = 4 × 10 19 cm −2 without significant changes between the two observations. Four XMM-Newton observations of RX
J0420.0−5022 between December 2002 and July 2003 did not confirm the 22.7 s pulsations originally indicated in ROSAT data, but clearly reveal a 3.453 s period. A fit to the X-ray spectrum using an absorbed black-body model yields kT = 45 eV, the lowest value found from the small group of XDINs and N H = 1.0 × 10 20 cm −2. Including a broad absorption line improves the quality of the spectral fits considerably for both objects and may indicate the presence of absorption features similar to those reported from RBS1223, RX J1605.3+3249 and RX J0720.4−3125. For both targets we derive accurate X-ray positions from the Chandra data and present an optical counterpart candidate for RX J0420.0−5022 with B = 26.6 ± 0.3 mag from VLT imaging
When is a life too costly to save? : evidence from U.S. environmental regulations
No full textExcept for two relatively minor statutes, U.S. environmental laws do not permit the balancing of costs and benefits in setting environmental standards. The Clean Air Act, for example, prohibits the Environmental Protection Agency (EPA) from considering costs in setting ambient air quality standards. Similarly, the Clean Water Act does not allow consideration of benefits in setting effluent standards. When the EPA is allowed to balance benefits against costs, it has considerable discretion in defining"balancing."The authors ask two questions: Whether allowed to or not, has the EPA balanced costs and benefits in setting environmental standards? Where has the EPA drawn the line in deciding how much to spend to save a statistical life? Their answers are based on data about the costs and benefits of regulations involving three classes of pollutants: cancer-causing pesticides usedon food crops (1975-89); carcinogenic air pollutants (1975-90); and all uses of asbestos regulated under the Toxic Substances Control Act. The following are their findings. The EPA behaved as though it were balancing costs and benefits in its regulation of pesticides under Federal Insecticide, Fungicide and Rodenticide Act (FIFRA) and of asbestos under Toxic Substance Control Act (TSCA), the two so-called balancing statutes. The higher the cost of the ban, the less likely the EPA was to ban the use of these products. The greater the number of lives saved, the more likely the EPA was to ban their use. But the amount the EPA was (implicitly) willing to spend to save a life was high: 49 million to avoid cancer through exposure to asbestos. The value the EPA attached to saving a life was higher for workers than for consumers. The value attached to avoiding a case of cancer through exposure to pesticide resides on food was less than 52 million value of preventing cancer among pesticide applicators - perhaps because workers are exposed to higher levels of pollution than consumers. After 1987, when the Natural Resources Defense Council sued the EPA for considering costs in setting emissions standards for vinyl chloride, the EPA considered costs in setting emissions standards only after an acceptable level of risk was achieved. Ironically, before the vinyl chloride decision, the value per cancer case avoided was only $15 million. The amount the EPA was willing to spend to save a life was thus less under the Clean Air Act than under the balancing statutes. But after this decision, the EPA did not consider costs at all if the risk of cancer to the maximally exposed individual was above one in 10,000.Environmental Economics&Policies,Health Monitoring&Evaluation,Economic Theory&Research,Health Economics&Finance,Montreal Protocol
The relationship between propagule pressure and establishment success in alien bird populations: a re-analysis of Moulton & Cropper (2019)
No full textA recent analysis by Moulton & Cropper (2019) of a global dataset on alien bird population introductions claims to find no evidence that establishment success is a function of the size of the founding population. Here, we re-analyse Moulton & Cropper’s data and show that this conclusion is based on flawed statistical methods—their data in fact confirm a strong positive relationship between founding population size and establishment success. We also refute several non-statistical arguments against the likelihood of such an effect presented by Moulton & Cropper. We conclude that a core tenet of population biology—that small populations are more prone to extinction—applies to alien populations beyond their native geographic range limits as much as to native populations within them
Why Have Traffic Fatalities Declined in Industrialized Countries' Implications for Pedestrians and Vehicle Occupants
No full textPrevious research suggests that the death rate due to traffic fatalities at first increases as countries develop and motorization increases, but eventually declines as incomes grow and fatalities per vehicle decrease (Kopits and Cropper, 2005). This paper examines whether the relationship between traffic fatalities and income is the same for different classes of road users and investigates the factors underlying the decline in fatalities per vehicle kilometer traveled (VKT) observed in high-income countries over recent decades. Formal models of traffic fatalities are developed for vehicle occupants and pedestrians. Reduced-form approximations to these models are estimated using panel data for 32 high-income countries over 1964-2002. The results suggest that the downward-sloping portion of the curve relating traffic fatalities per capita to per capita income is due primarily to improved pedestrian safety. Our more detailed models shed light on some factors influencing pedestrian fatalities per VKT but much of the reduction in pedestrian fatalities remains unexplained; however, increased motorization and a reduction in the proportion of young drivers in the population clearly played a role. Occupant fatalities, however, do not show a significant decline with income. What does explain declines in occupant fatalities per distance traveled are reductions in alcohol abuse and improved medical services, and a reduction in young drivers. The importance of demographic factors suggests that in countries where young persons (between 15 and 24 years of age) comprise an increasing share of the driving population, adopting policies to improve young driver education and reduce speeds will be crucial.
Handwritten biographical information on Paulina T. McClung Merritt
No full textA handwritten biography of Paulina T. McClung Merritt by an unknown author, 1892.
Heterogeneous and tissue-specific regulation of effector T cell responses by IFN-gamma during Plasmodium berghei ANKA infection.
No full textIFN-γ and T cells are both required for the development of experimental cerebral malaria during Plasmodium berghei ANKA infection. Surprisingly, however, the role of IFN-γ in shaping the effector CD4(+) and CD8(+) T cell response during this infection has not been examined in detail. To address this, we have compared the effector T cell responses in wild-type and IFN-γ(-/-) mice during P. berghei ANKA infection. The expansion of splenic CD4(+) and CD8(+) T cells during P. berghei ANKA infection was unaffected by the absence of IFN-γ, but the contraction phase of the T cell response was significantly attenuated. Splenic T cell activation and effector function were essentially normal in IFN-γ(-/-) mice; however, the migration to, and accumulation of, effector CD4(+) and CD8(+) T cells in the lung, liver, and brain was altered in IFN-γ(-/-) mice. Interestingly, activation and accumulation of T cells in various nonlymphoid organs was differently affected by lack of IFN-γ, suggesting that IFN-γ influences T cell effector function to varying levels in different anatomical locations. Importantly, control of splenic T cell numbers during P. berghei ANKA infection depended on active IFN-γ-dependent environmental signals--leading to T cell apoptosis--rather than upon intrinsic alterations in T cell programming. To our knowledge, this is the first study to fully investigate the role of IFN-γ in modulating T cell function during P. berghei ANKA infection and reveals that IFN-γ is required for efficient contraction of the pool of activated T cells
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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