446 research outputs found
Using nestedness and species-accumulation analyses to strengthen a conservation plan for littoral forest birds in south-eastern Madagascar
The littoral forests of south-eastern Madagascar are among the most threatened ecosystems on the island. A conservation plan has been developed for the region due to a proposed mining venture. Here, we provide a novel methodology to assess if the planned conservation measures would effectively conserve the bird diversity inhabiting these forests. Bird community composition within 30 littoral forest fragments was quantified with each fragment characterized by measures of fragment area, isolation, and internal habitat complexity. A nestedness and cumulative speciesâarea analysis was conducted to ascertain the contribution of forest fragments of different sizes in capturing the overall bird species richness. Datasets representing the overall and forest-dependent bird assemblages were found to be significantly nested. The pattern of nestedness appeared to be driven by fragment size. However, cumulative speciesâarea analyses showed that the assemblages were imperfectly nested with ten species displaying idiosyncratic distribution patterns. When a modest conservation target was set (the occurrence of a bird species in three or more fragments), the proposed conservation plan would only protect approximately half the species found in the littoral forests. We show that protecting an additional four large patches would mean that the proportion of forest-birds captured in three or more patches would increase to 70%
Canonical Nlrp3 Inflammasome Links Systemic Low-Grade Inflammation to Functional Decline in Aging
SummaryDespite a wealth of clinical data showing an association between inflammation and degenerative disorders in the elderly, the immune sensors that causally link systemic inflammation to aging remain unclear. Here we detail a mechanism by which the Nlrp3 inflammasome controls systemic low-grade age-related âsterileâ inflammation in both periphery and brain independently of the noncanonical caspase-11 inflammasome. Ablation of Nlrp3 inflammasome protected mice from age-related increases in the innate immune activation, alterations in CNS transcriptome, and astrogliosis. Consistent with the hypothesis that systemic low-grade inflammation promotes age-related degenerative changes, the deficient Nlrp3 inflammasome-mediated caspase-1 activity improved glycemic control and attenuated bone loss and thymic demise. Notably, IL-1 mediated only Nlrp3 inflammasome-dependent improvement in cognitive function and motor performance in aged mice. These studies reveal Nlrp3 inflammasome as an upstream target that controls age-related inflammation and offer an innovative therapeutic strategy to lower Nlrp3 activity to delay multiple age-related chronic diseases
Predicting the exposure of diving grey seals to shipping noise.
There is high spatial overlap between grey seals and shipping traffic, and the functional hearing range of grey seals indicates sensitivity to underwater noise emitted by ships. However, there is still very little data regarding the exposure of grey seals to shipping noise, constraining effective policy decisions. Particularly, there are few predictions that consider the at-sea movement of seals. Consequently, this study aimed to predict the exposure of adult grey seals and pups to shipping noise along a three-dimensional movement track, and assess the influence of shipping characteristics on sound exposure levels. Using ship location data, a ship source model, and the acoustic propagation model, RAMSurf, this study estimated weighted 24-h sound exposure levels (10-1000âHz) (SELw). Median predicted 24-h SELw was 128 and 142 dB re 1 ÎŒPa2s for the pups and adults, respectively. The predicted exposure of seals to shipping noise did not exceed best evidence thresholds for temporary threshold shift. Exposure was mediated by the number of ships, ship source level, the distance between seals and ships, and the at-sea behaviour of the seals. The results can inform regulatory planning related to anthropogenic pressures on seal populations
Search for gravitational waves from binary inspirals in S3 and S4 LIGO data
We report on a search for gravitational waves from the coalescence of compact
binaries during the third and fourth LIGO science runs. The search focused on
gravitational waves generated during the inspiral phase of the binary
evolution. In our analysis, we considered three categories of compact binary
systems, ordered by mass: (i) primordial black hole binaries with masses in the
range 0.35 M(sun) < m1, m2 < 1.0 M(sun), (ii) binary neutron stars with masses
in the range 1.0 M(sun) < m1, m2 < 3.0 M(sun), and (iii) binary black holes
with masses in the range 3.0 M(sun)< m1, m2 < m_(max) with the additional
constraint m1+ m2 < m_(max), where m_(max) was set to 40.0 M(sun) and 80.0
M(sun) in the third and fourth science runs, respectively. Although the
detectors could probe to distances as far as tens of Mpc, no gravitational-wave
signals were identified in the 1364 hours of data we analyzed. Assuming a
binary population with a Gaussian distribution around 0.75-0.75 M(sun), 1.4-1.4
M(sun), and 5.0-5.0 M(sun), we derived 90%-confidence upper limit rates of 4.9
yr^(-1) L10^(-1) for primordial black hole binaries, 1.2 yr^(-1) L10^(-1) for
binary neutron stars, and 0.5 yr^(-1) L10^(-1) for stellar mass binary black
holes, where L10 is 10^(10) times the blue light luminosity of the Sun.Comment: 12 pages, 11 figure
Search for Gravitational Waves Associated with 39 Gamma-Ray Bursts Using Data from the Second, Third, and Fourth LIGO Runs
We present the results of a search for short-duration gravitational-wave
bursts associated with 39 gamma-ray bursts (GRBs) detected by gamma-ray
satellite experiments during LIGO's S2, S3, and S4 science runs. The search
involves calculating the crosscorrelation between two interferometer data
streams surrounding the GRB trigger time. We search for associated
gravitational radiation from single GRBs, and also apply statistical tests to
search for a gravitational-wave signature associated with the whole sample. For
the sample examined, we find no evidence for the association of gravitational
radiation with GRBs, either on a single-GRB basis or on a statistical basis.
Simulating gravitational-wave bursts with sine-gaussian waveforms, we set upper
limits on the root-sum-square of the gravitational-wave strain amplitude of
such waveforms at the times of the GRB triggers. We also demonstrate how a
sample of several GRBs can be used collectively to set constraints on
population models. The small number of GRBs and the significant change in
sensitivity of the detectors over the three runs, however, limits the
usefulness of a population study for the S2, S3, and S4 runs. Finally, we
discuss prospects for the search sensitivity for the ongoing S5 run, and beyond
for the next generation of detectors.Comment: 24 pages, 10 figures, 14 tables; minor changes to text and Fig. 2;
accepted by Phys. Rev.
A Joint Search for Gravitational Wave Bursts with AURIGA and LIGO
The first simultaneous operation of the AURIGA detector and the LIGO
observatory was an opportunity to explore real data, joint analysis methods
between two very different types of gravitational wave detectors: resonant bars
and interferometers. This paper describes a coincident gravitational wave burst
search, where data from the LIGO interferometers are cross-correlated at the
time of AURIGA candidate events to identify coherent transients. The analysis
pipeline is tuned with two thresholds, on the signal-to-noise ratio of AURIGA
candidate events and on the significance of the cross-correlation test in LIGO.
The false alarm rate is estimated by introducing time shifts between data sets
and the network detection efficiency is measured with simulated signals with
power in the narrower AURIGA band. In the absence of a detection, we discuss
how to set an upper limit on the rate of gravitational waves and to interpret
it according to different source models. Due to the short amount of analyzed
data and to the high rate of non-Gaussian transients in the detectors noise at
the time, the relevance of this study is methodological: this was the first
joint search for gravitational wave bursts among detectors with such different
spectral sensitivity and the first opportunity for the resonant and
interferometric communities to unify languages and techniques in the pursuit of
their common goal.Comment: 18 pages, IOP, 12 EPS figure
Development of standardized laboratory methods and quality processes for a phase III study of the RTS, S/AS01 candidate malaria vaccine
BACKGROUND\ud
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A pivotal phase III study of the RTS,S/AS01 malaria candidate vaccine is ongoing in several research centres across Africa. The development and establishment of quality systems was a requirement for trial conduct to meet international regulatory standards, as well as providing an important capacity strengthening opportunity for study centres.\ud
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METHODS\ud
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Standardized laboratory methods and quality assurance processes were implemented at each of the study centres, facilitated by funding partners.\ud
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RESULTS\ud
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A robust protocol for determination of parasite density based on actual blood cell counts was set up in accordance with World Health Organization recommendations. Automated equipment including haematology and biochemistry analyzers were put in place with standard methods for bedside testing of glycaemia, base excess and lactacidaemia. Facilities for X-rays and basic microbiology testing were also provided or upgraded alongside health care infrastructure in some centres. External quality assurance assessment of all major laboratory methods was established and method qualification by each laboratory demonstrated. The resulting capacity strengthening has ensured laboratory evaluations are conducted locally to the high standards required in clinical trials.\ud
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CONCLUSION\ud
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Major efforts by study centres, together with support from collaborating parties, have allowed standardized methods and robust quality assurance processes to be put in place for the phase III evaluation of the RTS, S/AS01 malaria candidate vaccine. Extensive training programmes, coupled with continuous commitment from research centre staff, have been the key elements behind the successful implementation of quality processes. It is expected these activities will culminate in healthcare benefits for the subjects and communities participating in these trials.\ud
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TRIAL REGISTRATION\ud
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Clinicaltrials.gov NCT00866619
Assessing Natural Resource Use by Forest-Reliant Communities in Madagascar Using Functional Diversity and Functional Redundancy Metrics
Biodiversity plays an integral role in the livelihoods of subsistence-based forest-dwelling communities and as a consequence it is increasingly important to develop quantitative approaches that capture not only changes in taxonomic diversity, but also variation in natural resources and provisioning services. We apply a functional diversity metric originally developed for addressing questions in community ecology to assess utilitarian diversity of 56 forest plots in Madagascar. The use categories for utilitarian plants were determined using expert knowledge and household questionnaires. We used a null model approach to examine the utilitarian (functional) diversity and utilitarian redundancy present within ecological communities. Additionally, variables that might influence fluctuations in utilitarian diversity and redundancyâspecifically number of felled trees, number of trails, basal area, canopy height, elevation, distance from villageâwere analyzed using Generalized Linear Models (GLMs). Eighteen of the 56 plots showed utilitarian diversity values significantly higher than expected. This result indicates that these habitats exhibited a low degree of utilitarian redundancy and were therefore comprised of plants with relatively distinct utilitarian properties. One implication of this finding is that minor losses in species richness may result in reductions in utilitarian diversity and redundancy, which may limit local residents' ability to switch between alternative choices. The GLM analysis showed that the most predictive model included basal area, canopy height and distance from village, which suggests that variation in utilitarian redundancy may be a result of local residents harvesting resources from the protected area. Our approach permits an assessment of the diversity of provisioning services available to local communities, offering unique insights that would not be possible using traditional taxonomic diversity measures. These analyses introduce another tool available to conservation biologists for assessing how future losses in biodiversity will lead to a reduction in natural resources and provisioning services from forests
Genomic analysis of human lung fibroblasts exposed to vanadium pentoxide to identify candidate genes for occupational bronchitis
BACKGROUND: Exposure to vanadium pentoxide (V(2)O(5)) is a cause of occupational bronchitis. We evaluated gene expression profiles in cultured human lung fibroblasts exposed to V(2)O(5 )in vitro in order to identify candidate genes that could play a role in inflammation, fibrosis, and repair during the pathogenesis of V(2)O(5)-induced bronchitis. METHODS: Normal human lung fibroblasts were exposed to V(2)O(5 )in a time course experiment. Gene expression was measured at various time points over a 24 hr period using the Affymetrix Human Genome U133A 2.0 Array. Selected genes that were significantly changed in the microarray experiment were validated by RT-PCR. RESULTS: V(2)O(5 )altered more than 1,400 genes, of which ~300 were induced while >1,100 genes were suppressed. Gene ontology categories (GO) categories unique to induced genes included inflammatory response and immune response, while GO catogories unique to suppressed genes included ubiquitin cycle and cell cycle. A dozen genes were validated by RT-PCR, including growth factors (HBEGF, VEGF, CTGF), chemokines (IL8, CXCL9, CXCL10), oxidative stress response genes (SOD2, PIPOX, OXR1), and DNA-binding proteins (GAS1, STAT1). CONCLUSION: Our study identified a variety of genes that could play pivotal roles in inflammation, fibrosis and repair during V(2)O(5)-induced bronchitis. The induction of genes that mediate inflammation and immune responses, as well as suppression of genes involved in growth arrest appear to be important to the lung fibrotic reaction to V(2)O(5)
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