536 research outputs found

    Daily Activity Patterns of Two Co-Occurring Tropical Satyrine Butterflies

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    Adult males and females of many insect species are expected to adjust their daily activity pattern in order to avoid stressful climatic conditions and increase the chances to encounter sexual partners. Using scan sampling methods associated with focal individual observations it was found that two satyrine butterflies of similar size and morphology, Hermeuptychia hermes (Fabricius) (Leptidoptera: Nymphalidae) and Paryphthimoides phronius (Godart), show completely different daily activity patterns on forest edges in southeastern Brazil. Hermeuptychia hermes presents one abundance peak in the morning and another in the late afternoon, while P. phronius abundance peaks in the mid-day, remaining stable until 1700 h. This difference is probably due to the occurrence of territorial behavior in the later species. The beginning of territorial defense by P. phronius males coincided with the time of new-born female activity. However, newly hatched females were not sexually receptive. The afternoon territoriality in male P. phronius may be in part related to mate acquisition. However, why the abundance of H. hermes decreases when the abundance of P. phronius increases is less clear

    GLAST: Understanding the High Energy Gamma-Ray Sky

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    We discuss the ability of the GLAST Large Area Telescope (LAT) to identify, resolve, and study the high energy gamma-ray sky. Compared to previous instruments the telescope will have greatly improved sensitivity and ability to localize gamma-ray point sources. The ability to resolve the location and identity of EGRET unidentified sources is described. We summarize the current knowledge of the high energy gamma-ray sky and discuss the astrophysics of known and some prospective classes of gamma-ray emitters. In addition, we also describe the potential of GLAST to resolve old puzzles and to discover new classes of sources.Comment: To appear in Cosmic Gamma Ray Sources, Kluwer ASSL Series, Edited by K.S. Cheng and G.E. Romer

    Detection and identification by PCR of Clostridium chauvoei in clinical isolates, bovine faeces and substrates from biogas plant

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    <p>Abstract</p> <p>Background</p> <p><it>Clostridium chauvoei </it>causes blackleg, an acute disease associated with high mortality in ruminants. The apparent primary port of entry is oral, during grazing on pasture contaminated by spores. Cases of blackleg can occur year after year on contaminated pastures. A method to determine the prevalence of <it>C. chauvoei </it>spores on pasture would be useful.</p> <p>The standard method for <it>C. chauvoei </it>detection is culture and biochemical identification, which requires a pure culture. In most muscle samples from cattle dead from blackleg the amount of <it>C. chauvoei </it>in samples is high and the bacterium can easily be cultured, although some samples may be contaminated. Detection by PCR would be faster and independent of contaminating flora.</p> <p>Digested residues from biogas plants provide an excellent fertiliser, but it is known that spore-forming baeria such as <it>Clostridium </it>spp. are not reduced by pasteurisation. The use of digested residues as fertiliser may contribute to the spread of <it>C. chauvoei</it>. Soil, manure and substrate from biogas plants are contaminated with other anaerobic bacteria which outgrow <it>C. chauvoei</it>. Therefore, detection by PCR is would be useful. This study applied a PCR-based method to detect of <it>C. chauvoei </it>in 25 muscle and blood samples, 114 manure samples, 84 soil samples and 33 samples from the biogas process.</p> <p>Methods</p> <p>Muscle tissues from suspected cases of blackleg were analysed both by the standard culture method followed by biochemical identification and by PCR, with and without preculture. To investigate whether muscle tissue samples are necessary, samples taken by swabs were also investigated. Samples from a biogas plant and manure and soil from farms were analysed by culture followed by PCR. The farms had proven cases of blackleg. For detection of <it>C. chauvoei </it>in the samples, a specific PCR primer pair complementary to the spacer region of the 16S-23S rRNA gene was used.</p> <p>Results</p> <p><it>Clostridium chauvoei </it>was detected in 32% of muscle samples analysed by culture with identification by biochemical methods and in 56% of cases by culture in combination with PCR. <it>Clostridium chauvoei </it>was detected in 3 (out of 11) samples from the biogas plants collected before pasteurisation, but samples taken after pasteurisation and after digestion all tested negative. <it>Clostridium chauvoei </it>was not detected in any soil or silage samples and only one manure samples tested positive.</p> <p>Conclusion</p> <p>The diagnostic method used for <it>C. chauvoei </it>was not applicable in estimating the risk of blackleg on particular pastures from manure or soil samples, but found to be highly useful for clinical samples.</p

    Differential livelihood adaptation to social-ecological change in coastal Bangladesh

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    Social-ecological changes, brought about by the rapid growth of the aquaculture industry and the increased occurrence of climatic stressors, have significantly affected the livelihoods of coastal communities in Asian mega-deltas. This paper explores the livelihood adaptation responses of households of different wealth classes, the heterogeneous adaptation opportunities, barriers and limits (OBLs) faced by these households and the dynamic ways in which these factors interact to enhance or impede adaptive capacities. A mixed methods approach was used to collect empirical evidence from two villages in coastal Bangladesh. Findings reveal that households’ adaptive capacities largely depend on their wealth status, which not only determine their availability of productive resources, but also empower them to navigate social-ecological change in desirable ways. Households operate within a shared response space, which is shaped by the broader socio-economic and political landscape, as well as their previous decisions that can lock them in to particular pathways. While an adaptive response may be effective for one social group, it may cause negative externalities that can undermine the adaptation options and outcomes of another group. Adaptation OBLs interact in complex ways; the extent to which these OBLs affect different households depend on the specific livelihood activities being considered and the differential values and interests they hold. To ensure more equitable and environmentally sustainable livelihoods in future, policies and programs should aim to expand households’ adaptation space by accounting for the heterogeneous needs and complex interdependencies between response processes of different groups

    Perceived stressors of climate vulnerability across scales in the Savannah zone of Ghana: a participatory approach

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    Smallholder farmers in sub-Saharan Africa are confronted with climatic and non-climatic stressors. Research attention has focused on climatic stressors, such as rainfall variability, with few empirical studies exploring non-climatic stressors and how these interact with climatic stressors at multiple scales to affect food security and livelihoods. This focus on climatic factors restricts understanding of the combinations of stressors that exacerbate the vulnerability of farming households and hampers the development of holistic climate change adaptation policies. This study addresses this particular research gap by adopting a multi-scale approach to understand how climatic and non-climatic stressors vary, and interact, across three spatial scales (household, community and district levels) to influence livelihood vulnerability of smallholder farming households in the Savannah zone of northern Ghana. This study across three case study villages utilises a series of participatory tools including semi-structured interviews, key informant interviews and focus group discussions. The incidence, importance, severity and overall risk indices for stressors are calculated at the household, community, and district levels. Results show that climatic and non-climatic stressors were perceived differently; yet, there were a number of common stressors including lack of money, high cost of farm inputs, erratic rainfall, cattle destruction of crops, limited access to markets and lack of agricultural equipment that crossed all scales. Results indicate that the gender of respondents influenced the perception and severity assessment of stressors on rural livelihoods at the community level. Findings suggest a mismatch between local and district level priorities that have implications for policy and development of agricultural and related livelihoods in rural communities. Ghana’s climate change adaptation policies need to take a more holistic approach that integrates both climatic and non-climatic factors to ensure policy coherence between national climate adaptation plans and District development plans

    Physics, Astrophysics and Cosmology with Gravitational Waves

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    Gravitational wave detectors are already operating at interesting sensitivity levels, and they have an upgrade path that should result in secure detections by 2014. We review the physics of gravitational waves, how they interact with detectors (bars and interferometers), and how these detectors operate. We study the most likely sources of gravitational waves and review the data analysis methods that are used to extract their signals from detector noise. Then we consider the consequences of gravitational wave detections and observations for physics, astrophysics, and cosmology.Comment: 137 pages, 16 figures, Published version <http://www.livingreviews.org/lrr-2009-2

    Early Marine Migration Patterns of Wild Coastal Cutthroat Trout (Oncorhynchus clarki clarki), Steelhead Trout (Oncorhynchus mykiss), and Their Hybrids

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    Hybridization between coastal cutthroat trout (Oncorhynchus clarki clarki) and steelhead or rainbow trout (Oncorhynchus mykiss) has been documented in several streams along the North American west coast. The two species occupy similar freshwater habitats but the anadromous forms differ greatly in the duration of marine residence and migration patterns at sea. Intermediate morphological, physiological, and performance traits have been reported for hybrids but little information has been published comparing the behavior of hybrids to the pure species.This study used acoustic telemetry to record the movements of 52 cutthroat, 42 steelhead x cutthroat hybrids, and 89 steelhead smolts, all wild, that migrated from Big Beef Creek into Hood Canal (Puget Sound, Washington). Various spatial and temporal metrics were used to compare the behavior of the pure species to their hybrids. Median hybrid residence time, estuary time, and tortuosity values were intermediate compared to the pure species. The median total track distance was greater for hybrids than for either cutthroat or steelhead. At the end of each track, most steelhead (80%) were located near or north of the Hood Canal, as expected for this seaward migrating species, whereas most cutthroat (89%) were within 8 kilometers of the estuary. Most hybrids (70%) were detected leaving Hood Canal, though a substantial percentage (20%) remained near the Big Beef Creek estuary. More hybrids (7.5%) than pure cutthroat (4.5%) or steelhead (0.0%) were last detected in the southern reaches of Hood Canal.Given the similarity in freshwater ecology between the species, differences in marine ecology may play an important role in maintaining species integrity in areas of sympatry

    CRP identifies homeostatic immune oscillations in cancer patients: a potential treatment targeting tool?

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    The search for a suitable biomarker which indicates immune system responses in cancer patients has been long and arduous, but a widely known biomarker has emerged as a potential candidate for this purpose. C-Reactive Protein (CRP) is an acute-phase plasma protein that can be used as a marker for activation of the immune system. The short plasma half-life and relatively robust and reliable response to inflammation, make CRP an ideal candidate marker for inflammation. The high- sensitivity test for CRP, termed Low-Reactive Protein (LRP, L-CRP or hs-CRP), measures very low levels of CRP more accurately, and is even more reliable than standard CRP for this purpose. Usually, static sampling of CRP has been used for clinical studies and these can predict disease presence or recurrence, notably for a number of cancers. We have used frequent serial L-CRP measurements across three clinical laboratories in two countries and for different advanced cancers, and have demonstrated similar, repeatable observations of a cyclical variation in CRP levels in these patients. We hypothesise that these L-CRP oscillations are part of a homeostatic immune response to advanced malignancy and have some preliminary data linking the timing of therapy to treatment success. This article reviews CRP, shows some of our data and advances the reasoning for the hypothesis that explains the CRP cycles in terms of homeostatic immune regulatory cycles. This knowledge might also open the way for improved timing of treatment(s) for improved clinical efficacy
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