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Parasitism and Reproductive Effort in Male Rhesus Macaques: A Test of the Immunocompetence Handicap Hypothesis and the Stress-linked Immunocompetence Handicap Hypothesis
Get PDFDoes competition improve sovereign credit rating quality?
Get PDFThe market for sovereign ratings has been dominated by two agencies but credible new entrants have emerged. Decreasing market concentration has potentially significant implications for the quality of sovereign ratings. Using a global dataset from S&P, Moody’s, Fitch and DBRS for 2000-2016, we find that S&P and Moody’s ratings are higher (lower) in periods following increases in Fitch (DBRS) market share. Evidence suggests that DBRS employs a relatively lenient rating policy to proceed in this market but increased regulatory pressure on rating agencies weakens any tendency to inflate ratings to gain market share. We also find that sovereign rating strategies vary across the economic cycle. Our findings offer wide-ranging implications for market participants, policy makers and the rating industry
Unbundling the effect of political instability on income redistribution
Get PDFThe main objective of this study is to investigate potential political barriers to fostering an egalitarian redistribution of income within an economy. It empirically establishes that countries characterized by the prevalence of political instability are less likely to adopt progressive income redistribution. Employing data for up to 143 countries between 1996 and 2015, I consistently find evidence that political instability has a negative impact on effective fiscal redistribution, captured by the difference between market and net income inequality. Further analyses indicate that the economic and statistical significance of the redistributive impact of political instability is stronger in non-democratic and highly diverse societies, and low-income economies. Hence, the detrimental effect of political uncertainty on effective fiscal redistribution appears to hold only in non-democratic, fragmented and low-income countries. The findings imply that reducing political instability contributes to establishing an egalitarian redistribution of income, potentially leading to less income inequality
Supply-side cost-effectiveness thresholds: questions for evidence-based policy
Get PDFThere is growing interest in cost-effectiveness thresholds as a tool to inform resource allocation decisions in health care. Studies from several countries have sought to estimate health system opportunity costs, which supply-side cost-effectiveness thresholds are intended to represent. In this paper, we consider the role of empirical estimates of supply-side thresholds in policy-making. Recent studies estimate the cost per unit of health based on average displacement or outcome elasticity. We distinguish the types of point estimates reported in empirical work, including marginal productivity, average displacement, and outcome elasticity. Using this classification, we summarise the limitations of current approaches to threshold estimation in terms of theory, methods, and data. We highlight the questions that arise from alternative interpretations of thresholds and provide recommendations to policymakers seeking to use a supply-side threshold where the evidence base is emerging or incomplete. We recommend that: i) policymakers must clearly define the scope of the application of a threshold, and the theoretical basis for empirical estimates should be consistent with that scope; ii) a process for the assessment of new evidence and for determining changes in the threshold to be applied in policy-making should be created; iii) decision-making processes should retain flexibility in the application of a threshold, and iv) policymakers should provide support for decision-makers relating to the use of thresholds and the implementation of decisions stemming from their application
Coated ZrN sphere-UO2 composites as surrogates for UN-UO2 accident tolerant fuels
Get PDFUranium nitride (UN) spheres embedded in uranium dioxide (UO2) matrix isconsidered an innovative accident tolerant fuel (ATF). However, the interaction between UN and UO2 restricts the applicability of such composite in light water reactors. A possibility to limit this interaction is to separate the two materials with a diffusion barrier that has a high melting point, high thermal conductivity, and reasonably low neutron cross-section. Recent density functional theory calculations and experimental results on interface interactions in UN-X-UO2 systems (X = V, Nb, Ta, Cr, Mo, W) concluded that Mo and W are promising coating candidates. In this work, we develop and study different methods of coating ZrN spheres, used as a surrogate material for UN spheres: first, using Mo or W nanopowders (wet and binder); and second, using chemical vapour deposition (CVD) of W. ZrN-UO2 composites containing 15 wt% of coated ZrN spheres were consolidated by spark plasma sintering (1773 K, 80 MPa) and characterised by SEM/FIB-EDS and EBSD. The results show dense Mo and W layers without interaction with UO2. Wet and binder Mo methods provided coating layers of about 20 μm and 65 μm, respectively, while the binder and CVD of W methods layers of about 12 μm and 3 μm, respectivel
The Queen's Power to Honour Her Subjects
No full textThis short article offers some reflections on the role of the monarch in the British honours system, which dates back to the Norman conquest of 1066. It considers the role that the honours system plays in British life; how honours bind the Queen to her subjects; how criticisms of the honours system have often been ignored by government, and how better governance and transparency is required in order to maintain confidence in the honours system in the multiracial United Kingdo
Identifying critical habitat with archives: 275-year-old naturalist's notes provide high-resolution spatial evidence of long-term core habitat for a critically endangered shark
Get PDFHistorical sources can provide important data for modern-day threatened species conservation, such as identifying formerly important habitat on which to focus recovery efforts. Here we reveal unique written archival material from the 1740s that provides reliable first-hand observations of the Critically Endangered angel shark Squatina squatina, extending modern knowledge of this species in Welsh waters back by over half a century. These sources clearly identify small-scale and spatially explicit areas of abundance (including of juveniles) around specific reefs that align with more recent data, further strengthening evidence that these areas are of long-term importance that should be prioritised for the global conservation of this species, which has become extinct across much of its former range. These contemporary sources also describe fisheries for angel shark and high desirability, economic value and export trade of their meat, which could suggest that population declines of this intrinsically vulnerable species commenced centuries before modern science detected this. These unique observations highlight the value that historical material can provide in prioritising resource-limited conservation efforts, as well as helping to reframe our temporal understanding of elasmobranch fish declines
Local and large-scale spatial variation in a marine predator–prey interaction in the southwestern Atlantic
Get PDFPredator–prey interactions are a key ecological process which can be modified by environmental conditions over a range of spatial scales. Through two complementary short-term experiments, we assessed how local and large-scale environmental conditions affect a subtropical intertidal predator–prey interaction. At a local scale, we evaluated the effects of the degree of exposure to wave action and prey density on consumption rate and interaction strength using a whelk–barnacle system. Consumption rate decreased with wave exposure at experimentally reduced prey density but did not change at ambient density. Such an interactive effect occurred due to shifts in the whelk’s feeding behaviour, likely linked to encounter rate and stress amelioration underpinned by prey density. Per capita interaction strength of the whelk on the barnacle weakened along the wave exposure gradient, but to a greater degree at reduced compared to ambient prey density. This confirms that environmental harshness can decrease the importance of predators, but the magnitude of change may be modified by density-dependent effects. A large-scale experiment did not reveal spatial patterns in the whelk–barnacle interaction, nor relationships to chlorophyll-a concentration or the minor change in sea temperature across the study area. Patterns in the size of consumed barnacles along the chlorophyll-a gradient suggest changes in food choice related to prey quality and size. We conclude that disentangling the effects of wave exposure and prey density revealed important potential mechanisms driving species locally. Large-scale variation in the whelk–barnacle interaction appeared to be linked to species’ traits shaped by the environmental context