2,987 research outputs found
Gender-Specific Protection from Microvessel Rarefaction in Female Hypertensive Rats
Epidemiologic studies reveal that women have a significantly lower age-adjusted morbidity and mortality from cardiovascular disease than men, suggesting that gender is a cardiovascular disease risk factor. The mechanism of the “gender protection” is unknown. In this study, we investigated the microvascular remodeling in reduced renal mass plus a high salt (4.0% NaCl) diet model of hypertension (RRM + HS). We hypothesized that women would be protected from the increase in blood pressure and from the microvascular rarefaction associated with RRM + HS hypertension. Studies were designed to determine whether female rats were less susceptible to changes in microvessel density during RRM + HS. Microvessel density was measured in male and female low salt (0.4% LS) sham-operated controls (Sham + LS) and after 3 days or 4 weeks of RRM + HS hypertension. The microcirculation of hind limb (medial and lateral gastrocnemius, plantaris, soleus) muscles was visualized using rhodamine-labeled Griffonia simplicifolia I lectin. Tissue sections were examined by videomicroscopy and microvessel density was determined by quantitative stereology. As shown previously, mean arterial pressure increased to 160 ± 8 mm Hg and microvessel density decreased (\u3e30% decrease in all beds) in male RRM + HS. In contrast, mean arterial pressure of female RRM + HS rats was modestly increased from 101 ± 2 to 118 ± 4 mm Hg. Despite previous results showing a reduction in microvessel density of both normotensive and hypertensive male rats on a high salt diet, microvessel density of female RRM + HS rats was not reduced at either time. These results suggest that gender protection in the RRM rat extends beyond an attenuation of the increase in pressure to an immunity from microvascular rarefaction
Algal food and fuel coproduction can mitigate greenhouse gas emissions while improving land and water-use efficiency
The goals of ensuring energy, water, food, and climate security can often conflict.Microalgae (algae) are
being pursued as a feedstockfor both food and fuels—primarily due to algae’s high areal yield and ability
to grow on non-arable land, thus avoiding common bioenergy-food tradeoffs. However, algal cultivation
requires significant energy inputs that may limit potential emission reductions.We examine the tradeoffs
associated with producing fuel andfood from algae at the energy–food–water–climate nexus.We use the
GCAM integrated assessment model to demonstrate that algalfood production can promote reductions
in land-use change emissions through the offset of conventional agriculture. However,fuel production,
either via co-production of algal food and fuel or complete biomass conversion to fuel, is necessary to
ensure long-term emission reductions, due to the high energy costs of cultivation. Cultivation of salt–
water algae for food products may lead to substantial freshwater savings; but, nutrients for algae
cultivation will need to be sourced from waste streams to ensure sustainability. By reducing the land
demand of food production, while simultaneously enhancingfood and energy security, algae can further
enable the development of terrestrial bioenergy technologies including those utilizing carbon capture and
storage. Our results demonstrate that large-scale algae research and commercialization efforts should
focus on developing both food and energy products to achieve environmental goals.https://iopscience.iop.org/article/10.1088/1748-9326/11/11/114006/metaPublished versio
The Full-sky Astrometric Mapping Explorer -- Astrometry for the New Millennium
FAME is designed to perform an all-sky, astrometric survey with unprecedented
accuracy. It will create a rigid astrometric catalog of 4x10^7 stars with 5 <
m_V < 15. For bright stars, 5 < m_V < 9, FAME will determine positions and
parallaxes accurate to < 50 microarcseconds, with proper motion errors < 50
microarcseconds/year. For fainter stars, 9 < m_V < 15, FAME will determine
positions and parallaxes accurate to < 500 microarcseconds, with proper motion
errors < 500 microarcseconds/year. It will also collect photometric data on
these 4 x 10^7 stars in four Sloan DSS colors.Comment: 6 pages, 4 figures, to appear in "Working on the Fringe
Supply-Side Ecology and the Response of Zooplankton to Climate-Driven Changes in North Atlantic Ocean Circulation
Does predation control the diapausing stock of Calanus finmarchicus in the Gulf of Maine?
© The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Wiebe, P., Baumgartner, M., Copley, N., Lawson, G., Davis, C., Ji, R., & Greene, C. Does predation control the diapausing stock of Calanus finmarchicus in the Gulf of Maine? Progress In Oceanography, 206, (2022): 102861, https://doi.org/10.1016/j.pocean.2022.102861.The variability of zooplankton populations is controlled by external and internal forcing, with the former being principally large-scale changes in circulation, and the latter being driven by in situ growth, competition, and predation. Assessing the relative importance of these forcings is challenging and requires analyses of multifaceted observational data. As part of the U.S. GLOBEC Georges Bank program, a series of cruises were conducted in fall 1997, 1998, and 1999 to survey diapausing populations of Calanus finmarchicus and their predators in Wilkinson, Jordan, and Georges Basins of the Gulf of Maine. Station and underway sampling were conducted using net (1 m2 MOCNESS) and bioacoustic (BIOMAPER-II) systems, respectively, to acquire vertically stratified data for zooplankton biomass, taxonomic, size, and life-stage composition, together with associated environmental data. The results show that the autumn diapausing C. finmarchicus abundance was much lower in 1998 than in 1997 or 1999, even though the overall zooplankton biomass levels were comparable between the three years. The size frequency distribution of the diapausing individuals had a bi-modal pattern in 1997 and 1999, but a single mode in 1998, indicating the demise of an early cohort of the diapausing stock. The relative biomass and computed energy demand of potential invertebrate predators (euphausiids, decapods, medusae, and siphonophores) was found to be higher in 1998 and could account for the missing C. finmarchicus cohort. Evidence collected from this study supports the hypothesis that local predation has the potential to control the diapausing stock of C. finmarchicus in the Gulf of Maine.RJ received support from the Northeast US Shelf Long Term Ecological Research (NES-LTER) project (NSF OCE-1655686) and the US MBON Gulf of Maine project to NERACOOS (NOPP award NA19NOS0120197 and BOEMUMaine Cooperative Agreement M19AC00022) for analyzing the size data and working on the manuscript. Research support was provided by the US GLOBEC Georges Bank Program through the CILER Cooperative Agreement NA-67RJO148 (NOAA Coastal Ocean Program)
Marine microalgae commercial production improves sustainability of global fisheries and aquaculture
publishedVersio
Where does Cosmological Perturbation Theory Break Down?
We apply the effective field theory approach to the coupled metric-inflaton
system, in order to investigate the impact of higher dimension operators on the
spectrum of scalar and tensor perturbations in the short-wavelength regime. In
both cases, effective corrections at tree-level become important when the
Hubble parameter is of the order of the Planck mass, or when the physical wave
number of a cosmological perturbation mode approaches the square of the Planck
mass divided by the Hubble constant. Thus, the cut-off length below which
conventional cosmological perturbation theory does not apply is likely to be
much smaller than the Planck length. This has implications for the
observability of "trans-Planckian" effects in the spectrum of primordial
perturbations.Comment: 25 pages, uses FeynM
Climate vulnerability assessment for Pacific salmon and steelhead in the California Current Large Marine Ecosystem.
Major ecological realignments are already occurring in response to climate change. To be successful, conservation strategies now need to account for geographical patterns in traits sensitive to climate change, as well as climate threats to species-level diversity. As part of an effort to provide such information, we conducted a climate vulnerability assessment that included all anadromous Pacific salmon and steelhead (Oncorhynchus spp.) population units listed under the U.S. Endangered Species Act. Using an expert-based scoring system, we ranked 20 attributes for the 28 listed units and 5 additional units. Attributes captured biological sensitivity, or the strength of linkages between each listing unit and the present climate; climate exposure, or the magnitude of projected change in local environmental conditions; and adaptive capacity, or the ability to modify phenotypes to cope with new climatic conditions. Each listing unit was then assigned one of four vulnerability categories. Units ranked most vulnerable overall were Chinook (O. tshawytscha) in the California Central Valley, coho (O. kisutch) in California and southern Oregon, sockeye (O. nerka) in the Snake River Basin, and spring-run Chinook in the interior Columbia and Willamette River Basins. We identified units with similar vulnerability profiles using a hierarchical cluster analysis. Life history characteristics, especially freshwater and estuary residence times, interplayed with gradations in exposure from south to north and from coastal to interior regions to generate landscape-level patterns within each species. Nearly all listing units faced high exposures to projected increases in stream temperature, sea surface temperature, and ocean acidification, but other aspects of exposure peaked in particular regions. Anthropogenic factors, especially migration barriers, habitat degradation, and hatchery influence, have reduced the adaptive capacity of most steelhead and salmon populations. Enhancing adaptive capacity is essential to mitigate for the increasing threat of climate change. Collectively, these results provide a framework to support recovery planning that considers climate impacts on the majority of West Coast anadromous salmonids
Friedreich ataxia patient tissues exhibit increased 5-hydroxymethylcytosine modification and decreased CTCF binding at the FXN locus
© 2013 Al-Mahdawi et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use,distribution, and reproduction in any medium, provided the original author and source are credited.This article has been made available through the Brunel Open Access Publishing Fund.Friedreich ataxia (FRDA) is caused by a homozygous GAA repeat expansion mutation within intron 1 of the FXN gene, which induces epigenetic changes and FXN gene silencing. Bisulfite sequencing studies have identified 5-methylcytosine (5 mC) DNA methylation as one of the epigenetic changes that may be involved in this process. However, analysis of samples by bisulfite sequencing is a time-consuming procedure. In addition, it has recently been shown that 5-hydroxymethylcytosine (5 hmC) is also present in mammalian DNA, and bisulfite sequencing cannot distinguish between 5 hmC and 5 mC.The research leading to these results has received funding from the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement number 242193/EFACTS (CS), the Wellcome Trust [089757] (SA) and Ataxia UK (RMP) to MAP
- …