375 research outputs found

    Trends and Variability in Localized Precipitation Around Kibale National Park, Uganda, Africa

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    Our objective was to understand and describe local spatial and temporal variability in precipitation around Kibale National Park, a tropical forest area of high conservation value. Continental or regional-scale trends are often relied upon to make policy and management decisions, but these analyses are often at too coarse a resolution to capture important variability at a finer scale where management actions operate. Monthly rainfall data derived from ten long-term station records (1941-1975) were used to evaluate local spatiotemporal variability in seasonal and annual rainfall for the area surrounding Kibale National Park. The magnitude, direction and significance of trends in seasonal and annual rainfall within the area surrounding the park were identified using the Mann-Kendall trend test and Sen’s slope estimator. The standardized precipitation index was calculated at 3- and 12-month periods to identify areas of relative wetness or dryness. Analysis of annual trends and precipitation indices indicated that patterns in annual time series do not reflect the direction and magnitude of seasonal trends nor the spatial variability in intra-annual rainfall at the local scale. Significant negative trends in the seasonal long rains, following dry season and short rains were identified at stations west of Kibale, while significant positive trends in the seasonal short rains occurred at stations north of the park. Stations along the western park boundary tended to have more years in which the two dry seasons were abnormally dry than those stations located further from the park

    Two thirds of species in a global shark fin trade hub are threatened with extinction: Conservation potential of international trade regulations for coastal sharks

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    One third of chondrichthyan species (sharks, rays, and chimeras) are threatened with extinction, mainly due to unsustainable fishing. Large accessible international markets for meat and luxury products like dried fins can help drive overfishing by encouraging targeted capture or retention of high-value export species. If this is common, then species in international trade could have heightened extinction risk. Here, we examined the species composition of the Hong Kong shark fin market from 2014 to 2018, finding that traded species disproportionately occur in threatened categories (70.9%) and all premium value species are threatened. A small number of cosmopolitan species dominate the trade, but noncosmopolitan coastal species are still traded at concerning levels given their limited distribution. These coastal species are not generally subject to retention prohibitions, fisheries management, or international trade regulations and without management many could become extinct. The conservation potential of international trade regulations alone for coastal chondrichthyans depends on the extent to which overfishing is driven by export markets; socioeconomic studies of coastal fishing communities are needed to make this determination. Nonetheless, adding international trade regulations for more coastal shark species that are in the fin trade could prompt broad engagement with overfishing in nations lacking effective management

    Serologic Evidence for Novel Poxvirus in Endangered Red Colobus Monkeys, Western Uganda

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    Enzyme-linked immunosorbent assay, Western blot, and virus neutralization assays indicated that red colobus monkeys in Kibale National Park, western Uganda, had antibodies to a virus that was similar, but not identical, to known orthopoxviruses. The presence of a novel poxvirus in this endangered primate raises public health and conservation concerns

    Acute sleep deprivation increases portion size and affects food choice in young men

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    SummaryAcute sleep loss increases food intake in adults. However, little is known about the influence of acute sleep loss on portion size choice, and whether this depends on both hunger state and the type of food (snack or meal item) offered to an individual. The aim of the current study was to compare portion size choice after a night of sleep and a period of nocturnal wakefulness (a condition experienced by night-shift workers, e.g. physicians and nurses). Sixteen men (age: 23±0.9 years, BMI: 23.6±0.6kg/m2) participated in a randomized within-subject design with two conditions, 8-h of sleep and total sleep deprivation (TSD). In the morning following sleep interventions, portion size, comprising meal and snack items, was measured using a computer-based task, in both fasted and sated state. In addition, hunger as well as plasma levels of ghrelin were measured. In the morning after TSD, subjects had increased plasma ghrelin levels (13%, p=0.04), and chose larger portions (14%, p=0.02), irrespective of the type of food, as compared to the sleep condition. Self-reported hunger was also enhanced (p<0.01). Following breakfast, sleep-deprived subjects chose larger portions of snacks (16%, p=0.02), whereas the selection of meal items did not differ between the sleep interventions (6%, p=0.13). Our results suggest that overeating in the morning after sleep loss is driven by both homeostatic and hedonic factors. Further, they show that portion size choice after sleep loss depend on both an individual's hunger status, and the type of food offered

    Moray eels are more common on coral reefs subject to higher human pressure in the greater Caribbean

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    Proximity and size of the nearest market (‘market gravity’) have been shown to have strong negative effects on coral reef fish communities that can be mitigated by the establishment of closed areas. However, moray eels are functionally unique predators that are generally not subject to targeted fishing and should therefore not directly be affected by these factors. We used baited remote underwater video systems to investigate associations between morays and anthropogenic, habitat, and ecological factors in the Caribbean region. Market gravity had a positive effect on morays, while the opposite pattern was observed in a predator group subject to exploitation (sharks). Environmental DNA analyses corroborated the positive effect of market gravity on morays. We hypothesize that the observed pattern could be the indirect result of the depletion of moray competitors and predators near humans. Environmental science; ecology; biological sciences; zoology; animals; etholog

    Epigenetic Differences in Cortical Neurons from a Pair of Monozygotic Twins Discordant for Alzheimer's Disease

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    DNA methylation [1], [2] is capable of modulating coordinate expression of large numbers of genes across many different pathways, and may therefore warrant investigation for their potential role between genes and disease phenotype. In a rare set of monozygotic twins discordant for Alzheimer's disease (AD), significantly reduced levels of DNA methylation were observed in temporal neocortex neuronal nuclei of the AD twin. These findings are consistent with the hypothesis that epigenetic mechanisms may mediate at the molecular level the effects of life events on AD risk, and provide, for the first time, a potential explanation for AD discordance despite genetic similarities

    Spitzer MIPS 24 and 70 micron Imaging near the South Ecliptic Pole: Maps and Source Catalogs

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    We have imaged an 11.5 sq. deg. region of sky towards the South Ecliptic Pole (RA = 04h43m, Dec = -53d40m, J2000) at 24 and 70 microns with MIPS, the Multiband Imaging Photometer for Spitzer. This region is coincident with a field mapped at longer wavelengths by AKARI and the Balloon-borne Large Aperture Submillimeter Telescope. We discuss our data reduction and source extraction procedures. The median depths of the maps are 47 microJy/beam at 24 micron and 4.3 mJy/beam at 70 micron. At 24 micron, we identify 93098 point sources with signal-to-noise ratio (SNR) >5, and an additional 63 resolved galaxies; at 70 micron, we identify 891 point sources with SNR >6. From simulations, we determine a false detection rate of 1.8% (1.1%) for the 24 micron (70 micron) catalog. The 24 and 70 micron point-source catalogs are 80% complete at 230 microJy and 11 mJy, respectively. These mosaic images and source catalogs will be available to the public through the NASA/IPAC Infrared Science Archive.Comment: 30 pages, 9 figures, 4 tables. Submitted to ApJS. Maps and catalogs can be downloaded from http://blastexperiment.info/release/SEP_MIPS/sep-mips.php, and will be soon be available through IRS

    Patterns and Perceptions of Climate Change in a Biodiversity Conservation Hotspot

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    Quantifying local people's perceptions to climate change, and their assessments of which changes matter, is fundamental to addressing the dual challenge of land conservation and poverty alleviation in densely populated tropical regions To develop appropriate policies and responses, it will be important not only to anticipate the nature of expected changes, but also how they are perceived, interpreted and adapted to by local residents. The Albertine Rift region in East Africa is one of the world's most threatened biodiversity hotspots due to dense smallholder agriculture, high levels of land and resource pressures, and habitat loss and conversion. Results of three separate household surveys conducted in the vicinity of Kibale National Park during the late 2000s indicate that farmers are concerned with variable precipitation. Many survey respondents reported that conditions are drier and rainfall timing is becoming less predictable. Analysis of daily rainfall data for the climate normal period 1981 to 2010 indicates that total rainfall both within and across seasons has not changed significantly, although the timing and transitions of seasons has been highly variable. Results of rainfall data analysis also indicate significant changes in the intra-seasonal rainfall distribution, including longer dry periods within rainy seasons, which may contribute to the perceived decrease in rainfall and can compromise food security. Our results highlight the need for fine-scale climate information to assist agro-ecological communities in developing effective adaptive management

    The ecology and epidemiology of malaria parasitism in wild chimpanzee reservoirs

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    This work was supported by grants from the National Institutes of Health R01AI091595, R01AI120810, R01AI050529, and P30AI045008 (B.H.H.); R01HL139337 (M.T.D.), the National Geographic Society (E.J.S.), the International Primatological Society (E.J.S.), and the American Society of Primatologists (E.J.S.), as well as fellowships from Harvard University (E.J.S.) and the National Science Foundation (E.J.S.).Chimpanzees (Pan troglodytes) harbor rich assemblages of malaria parasites, including three species closely related to P. falciparum (sub-genus Laverania), the most malignant human malaria parasite. Here, we characterize the ecology and epidemiology of malaria infection in wild chimpanzee reservoirs. We used molecular assays to screen chimpanzee fecal samples, collected longitudinally and cross-sectionally from wild populations, for malaria parasite mitochondrial DNA. We found that chimpanzee malaria parasitism has an early age of onset and varies seasonally in prevalence. A subset of samples revealed Hepatocystis mitochondrial DNA, with phylogenetic analyses suggesting that Hepatocystis appears to cross species barriers more easily than Laverania. Longitudinal and cross-sectional sampling independently support the hypothesis that mean ambient temperature drives spatiotemporal variation in chimpanzee Laverania infection. Infection probability peaked at ~24.5 °C, consistent with the empirical transmission optimum of P. falciparum in humans. Forest cover was also positively correlated with spatial variation in Laverania prevalence, consistent with the observation that forest-dwelling Anophelines are the primary vectors. Extrapolating these relationships across equatorial Africa, we map spatiotemporal variation in the suitability of chimpanzee habitat for Laverania transmission, offering a hypothetical baseline indicator of human exposure risk.Publisher PDFPeer reviewe
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