1,393 research outputs found

    Deep MOS Spectroscopy of NGC 1316 Globular Clusters

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    The giant elliptical galaxy NGC 1316 is the brightest galaxy in the Fornax cluster, and displays a number of morphological features that might be interpreted as an intermediate age merger remanent (∼\sim3 Gyr). Based on the idea that globular clusters systems (GCS) constitute genuine tracers of the formation and evolution of their host galaxies, we conducted a spectroscopic study of approximately 40 globular clusters (GCs) candidates associated with this interesting galaxy. We determined ages, metallicities, and α\alpha-element abundances for each GC present in the sample, through the measurement of different Lick indices and their subsequent comparison with simple stellar populations models (SSPs).Comment: 5 pages, 3 figure

    The performance of index based livestock insurance: ex ante assessment in the presence of a poverty trap

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    This paper evaluates the effectiveness of a new index-based livestock insurance (IBLI) product designed to compensate for area average predicted livestock mortality loss in northern Kenya, where previous work has established the presence of poverty traps. We simulate household-specific wealth dynamics based on a model parameterized using rich panel and experimental data from the region. The simulations allow us to investigate patterns of willingness to pay for asset index insurance that is imperfectly correlated with individuals' loss experience. The bifurcated livestock dynamics associated with the poverty trap gives rise to insurance valuation that is highly nonlinear in individual herd size. Willingness to pay among vulnerable groups who most need insurance are, on average, lower than commercially viable rates but subsidization of IBLI premiums appears to offer more cost-effective poverty reduction than direct transfers to the poor

    Integrating ecology into macroevolutionary research

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    On 9 March, over 150 biologists gathered in London for the Centre for Ecology and Evolution spring symposium, ‘Integrating Ecology into Macroevolutionary Research’. The event brought together researchers from London-based institutions alongside others from across the UK, Europe and North America for a day of talks. The meeting highlighted methodological advances and recent analyses of exemplar datasets focusing on the exploration of the role of ecological processes in shaping macroevolutionary patterns

    Memory Complaint in a Community Sample Aged 70 and Older

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/111116/1/j.1532-5415.2000.tb02634.x.pd

    Prevalence and Correlates of Depressive Symptoms in a Community Sample of People Suffering from Heart Failure

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    To examine the rates and correlates of depressive symptoms and syndromal depression in people with self-reported heart failure participating in a community study of people aged 70 and older. DESIGN: Cross-sectional. SETTING: Community-based epidemiological study of older people from the continental United States. PARTICIPANTS: Six thousand one hundred twenty-five older people participating in the longitudinal study of Assets and Health Dynamics. Participants had to be born in 1923 or earlier. MEASUREMENTS: The short-form Composite International Diagnostic Interview assessed syndromal depression, and a revised version of the Center for Epidemiologic Studies—Depression scale assessed depressive symptoms. Medical illness was based on self-report. The authors compared the rates of syndromal depression and individual depressive symptoms in people with self-reported heart failure (n = 199) with those in people with other heart conditions (n = 1,856) and with no heart conditions (n = 4,070). RESULTS: Eleven percent of those with heart failure met criteria for syndromal depression, compared with 4.8% of people with other heart conditions and 3.2% of those with no heart conditions. The association between heart failure and depression held even after controlling for disability, reported fatigue and breathlessness, and number of comorbid chronic illnesses. CONCLUSION: Community-living older people with self-reported heart failure were at approximately twice the risk for syndromal depression of the rest of the community. Although fatigue and functional disability were also related to depression in this sample, these variables did not account for the association between syndromal depression and self-reported heart failure.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66305/1/j.1532-5415.2002.50612.x.pd

    Response of beam-to-column web cleated joints for FRP pultruded members

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    Physical testing is used to characterize the structural properties of beam-to-column joints, comprising pultruded fiber-reinforced polymer (FRP) H-shapes of depth 203 mm, connected by 128 mm-long web cleats and two M16 bolts per leg. Testing is performed on two batches of nominally identical specimens. One batch had web cleats of pultruded FRP and the other had structural steel. The structural behavior of the joints is based on their moment-rotation responses, failure modes, and serviceability vertical deflection limits. Joints with FRP cleats failed by delamination cracking at the top of the cleats, and when the cleats were of steel, the FRP failure occurred inside the column members. Neither failure mode is reported in the design manuals from pultruders. At the onset of the FRP damage, it was found that the steel joints were twice as stiff as the FRP joints. On the basis of a characteristic (damage) rotation, calculated in accordance with Eurocode 0, the serviceability deflection limits are established to be span/300 and span/650 for the joints with FRP and steel cleats, respectively. This finding suggests that appropriate deflection limits, in relation to cleated connections, should be proposed in manufactures’ design manuals and relative design standards and design codes. Failure to address the serviceability, by the engineer of record, could lead to unreliable designs

    Global patterns of extinction risk and conservation needs for Rodentia and Eulipotyphla

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    AIM: To explore global patterns in spatial aggregations of species richness, vulnerability and data deficiency for Rodentia and Eulipotyphla. To evaluate the adequacy of existing protected area (PA) network for these areas. To provide a focus for local conservation initiatives. LOCATION: Global. METHODS: Total species, globally threatened (GT) species, and Data Deficient (DD) species richness were calculated for a 1° resolution grid. Correspondence analyses between global species richness against GT species richness were performed. To assess PA network adequacy, a correspondence analysis was conducted to identify areas of high richness and GT species richness that have poor protection. RESULTS: Six hotspots were identified for GT eulipotyphlans, encompassing 40% of GT species. Three of these contain higher numbers of GT species than would be expected based on their overall species richness. Ten priority regions were identified for GT rodents, which together contain 34% of all GT species. Six contain higher numbers of GT rodent species than would be expected based on their overall species richness. For DD species, 15% of DD eulipotyphlans were represented within three priority regions, whereas 18 were identified for rodents, capturing 53% of all DD species. Areas containing lower numbers of protected GT eulipotyphlan species than expected include Mexico; Cameroonian Highlands; Albertine Rift; Tanzania; Kenya; Ethiopia; western Asia; India; and Sri Lanka. Areas containing lower numbers of protected GT rodent species than expected are Borneo, Sumatra and Sulawesi. Five eulipotyphlans and 44 rodents have ranges which fall completely outside of PAs. MAIN CONCLUSION: Rodentia and Eulipotyphla priority regions should be considered separately to one another and to other mammals. This analysis approach allows us to pinpoint and delineate geographical areas which represent key regions at a global level for rodents and eulipotyphlans, in order to facilitate conservation, field research and capacity building at a local level

    Are forested buffers an effective conservation strategy for riparian fauna? An assessment using meta-analysis

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    Historically, forested riparian buffers have been created to provide protection for aquatic organisms and aquatic ecosystem functions. Increasingly, new and existing riparian buffers are being used also to meet terrestrial conservation requirements. To test the effectiveness of riparian buffers for conserving terrestrial fauna, we conducted a meta-analysis using published data from 397 comparisons of species abundance in riparian buffers and unharvested (reference) riparian sites. The response of terrestrial species to riparian buffers was not consistent between taxonomic groups; bird and arthropod abundances were significantly greater in buffers relative to unharvested areas, whereas amphibian abundance decreased. Edge-preferring species were more abundant in buffer sites than reference sites, whereas species associated with interior habitat were not significantly different in abundance. The degree of buffer effect on animal abundance was unrelated to buffer width; wider buffers did not result in greater similarity between reference and buffer sites. However, responses to buffer treatment were more variable in buffers ,50 m wide, a commonly prescribed width in many management plans. Our results indicate that current buffer prescriptions do not maintain most terrestrial organisms in buffer strips at levels comparable to undisturbed sites

    Contrasting ecological information content in whaling archives with modern cetacean surveys for conservation planning and identification of historical distribution changes.

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    Many species are restricted to a marginal or suboptimal fraction of their historical range due to anthropogenic impacts, making it hard to interpret their ecological preferences from modern-day data alone. However, inferring past ecological states is limited by the availability of robust data and biases in historical archives, posing a challenge for policy makers . To highlight how historical records can be used to understand the ecological requirements of threatened species and inform conservation, we investigated sperm whale (Physeter macrocephalus) distribution in the Western Indian Ocean. We assessed differences in information content and habitat suitability predictions based on whale occurrence data from Yankee whaling logs (1792-1912) and from modern cetacean surveys (1995-2020). We built maximum entropy habitat suitability models containing static (bathymetry-derived) variables to compare models comprising historical-only and modern-only data. Using both historical and modern habitat suitability predictions  we assessed marine protected area (MPA) placement by contrasting suitability in- and outside MPAs. The historical model predicted high habitat suitability in shelf and coastal regions near continents and islands, whereas the modern model predicted a less coastal distribution with high habitat suitability more restricted to areas of steep topography. The proportion of high habitat suitability inside versus outside MPAs was higher when applying the historical predictions than the modern predictions, suggesting that different marine spatial planning optimums can be reached from either data sources. Moreover, differences in relative habitat suitability predictions between eras were consistent with the historical depletion of sperm whales from coastal regions, which were easily accessed and targeted by whalers, resulting in a modern distribution limited more to steep continental margins and remote oceanic ridges. The use of historical data can provide important new insights and, through cautious interpretation, inform conservation planning and policy, for example, by identifying refugee species and regions of anticipated population recovery
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