224 research outputs found
Effects of urbanization on the size and spatial distribution of wetlands in New Hampshire
This study investigates the effects of land use change in the form of urbanization on the size and spatial distribution of wetlands in New Hampshire. I predict that with increased urbanization, the number of wetlands lost will rise, causing an increase in landscape fragmentation. Aerial photography, US Geological Survey topographic maps, National Agriculture Imagery Program imagery, hydrography and National Wetlands Inventory data layers were analyzed using GIS tools along four urban-rural gradient transects 5km by 25km in size. Each study area transect included urban, suburban and rural areas. This study identified the relationships between the urbanization level and the size and spatial patterns of wetlands. A relationship between wetland distribution and urbanization as well as wetland size and urbanization was found for all study area transects. The results from this study suggest that wetland size and spatial distribution are being negatively affected by land use change within New Hampshire
A truncation allele in vascular endothelial growth factor c reveals distinct modes of signaling during lymphatic and vascular development
Vascular endothelial growth factor C (Vegfc) is a secreted protein that guides lymphatic development in vertebrate embryos. However, its role during developmental angiogenesis is not well characterized. Here, we identify a mutation in zebrafish vegfc that severely affects lymphatic development and leads to angiogenesis defects on sensitized genetic backgrounds. The um18 mutation prematurely truncated Vegfc, blocking its secretion and paracrine activity but not its ability to activate its receptor Flt4. When expressed in endothelial cells, vegfc(um18) could not rescue lymphatic defects in mutant embryos, but induced ectopic blood vessel branching. Furthermore, vegfc-deficient endothelial cells did not efficiently contribute to tip cell positions in developing sprouts. Computational modeling together with assessment of endothelial cell dynamics by time-lapse analysis suggested that an autocrine Vegfc/Flt4 loop plays an important role in migratory persistence and filopodia stability during sprouting. Our results suggest that Vegfc acts in two distinct modes during development: as a paracrine factor secreted from arteries to guide closely associated lymphatic vasculature and as an autocrine factor to drive migratory persistence during angiogenesis
Direct Imaging in Reflected Light: Characterization of Older, Temperate Exoplanets With 30-m Telescopes
Direct detection, also known as direct imaging, is a method for discovering
and characterizing the atmospheres of planets at intermediate and wide
separations. It is the only means of obtaining spectra of non-transiting
exoplanets. Characterizing the atmospheres of planets in the <5 AU regime,
where RV surveys have revealed an abundance of other worlds, requires a
30-m-class aperture in combination with an advanced adaptive optics system,
coronagraph, and suite of spectrometers and imagers - this concept underlies
planned instruments for both TMT (the Planetary Systems Imager, or PSI) and the
GMT (GMagAO-X). These instruments could provide astrometry, photometry, and
spectroscopy of an unprecedented sample of rocky planets, ice giants, and gas
giants. For the first time habitable zone exoplanets will become accessible to
direct imaging, and these instruments have the potential to detect and
characterize the innermost regions of nearby M-dwarf planetary systems in
reflected light. High-resolution spectroscopy will not only illuminate the
physics and chemistry of exo-atmospheres, but may also probe rocky, temperate
worlds for signs of life in the form of atmospheric biomarkers (combinations of
water, oxygen and other molecular species). By completing the census of
non-transiting worlds at a range of separations from their host stars, these
instruments will provide the final pieces to the puzzle of planetary
demographics. This whitepaper explores the science goals of direct imaging on
30-m telescopes and the technology development needed to achieve them.Comment: (March 2018) Submitted to the Exoplanet Science Strategy committee of
the NA
Estimating the global burden of endemic canine rabies
Background: Rabies is a notoriously underreported and neglected disease of lowincome
countries. This study aims to estimate the public health and economic burden
of rabies circulating in domestic dog populations, globally and on a country-by-country
basis, allowing an objective assessment of how much this preventable disease costs
endemic countries.<p></p>
Methodology/Principal Findings: We established relationships between rabies mortality
and rabies prevention and control measures, which we incorporated into a model
framework. We used data derived from extensive literature searches and
questionnaires on disease incidence, control interventions and preventative measures
within this framework to estimate the disease burden. The burden of rabies impacts on
public health sector budgets, local communities and livestock economies, with the
highest risk of rabies in the poorest regions of the world. This study estimates that
globally canine rabies causes approximately 59,000 (95% Confidence Intervals: 25-
159,000) human deaths, over 3.7 million (95% CIs: 1.6-10.4 million) disability-adjusted
life years (DALYs) and 8.6 billion USD (95% CIs: 2.9-21.5 billion) economic losses
annually. The largest component of the economic burden is due to premature death
(55%), followed by direct costs of post-exposure prophylaxis (PEP, 20%) and lost
income whilst seeking PEP (15.5%), with only limited costs to the veterinary sector due
to dog vaccination (1.5%), and additional costs to communities from livestock losses
(6%).<p></p>
Conclusions/Significance: This study demonstrates that investment in dog vaccination,
the single most effective way of reducing the disease burden, has been inadequate
and that the availability and affordability of PEP needs improving. Collaborative
investments by medical and veterinary sectors could dramatically reduce the current
large, and unnecessary, burden of rabies on affected communities. Improved
surveillance is needed to reduce uncertainty in burden estimates and to monitor the
impacts of control efforts.<p></p>
Evaluating whole grain intervention study designs and reporting practices using evidence mapping methodology
Consumption of whole grains have been associated with reduced risk of chronic diseases in many observational studies; yet, results of intervention studies are mixed. We aimed to use evidence mapping to capture the methodological and reporting variability in whole grain intervention studies that may contribute to this inconsistency. We conducted a reproducible search in OVID Medline for whole grain human intervention studies (published 1946 to February 2018). After screening based on a priori criteria, we identified 202 publications describing a total of 213 unique trials. Over half (55%) were acute trials, lasting ≤1 day, 30% were moderate duration studies (up to 6 weeks) and 15% were of longer duration (more than 6 weeks). The majority of acute trials (75%) examined measures of glycaemia and/or insulinemia, while most of the longer trials included measures of cardiometabolic health (71%), appetite/satiety (57%) and weight/adiposity (56%). Among the moderate and long duration trials, there was a wide range of how whole grains were described but only 10 publications referenced an established definition. Only 55% of trials reported the actual amount of whole grains (in grams or servings), while 36% reported the amount of food/product and 9% did not report a dose at all. Of the interventions that provided a mixture of whole grains, less than half (46%) reported the distribution of the different grain types. Reporting of subject compliance also varied and only 22% used independent biomarkers of whole grain intake. This evidence map highlights the need to standardize both study protocols and reporting practices to support effective synthesis of study results and provide a stronger foundation to better inform nutrition scientists and public health policy
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