1,768 research outputs found
Inducible nitric oxide synthase, Nos2, does not mediate optic neuropathy and retinopathy in the DBA/2J glaucoma model
<p>Abstract</p> <p>Background</p> <p>Nitric oxide synthase 2 (NOS2) contributes to neural death in some settings, but its role in glaucoma remains controversial. NOS2 is implicated in retinal ganglion cell degeneration in a rat glaucoma model in which intraocular pressure (IOP) is experimentally elevated by blood vessel cauterization, but not in a rat glaucoma model where IOP was elevated by injection of hypertonic saline. To test the importance of NOS2 for an inherited glaucoma, in this study we both genetically and pharmacologically decreased NOS2 activity in the DBA/2J mouse glaucoma model.</p> <p>Methods</p> <p>The expression of <it>Nos2 </it>in the optic nerve head was analyzed at both the RNA and protein levels at different stages of disease pathogenesis. To test the involvement of <it>Nos2 </it>in glaucomatous neurodegeneration, a null allele of <it>Nos2 </it>was backcrossed into DBA/2J mice and the incidence and severity of glaucoma was assessed in mice of each <it>Nos2 </it>genotype. Additionally, DBA/2J mice were treated with the NOS2 inhibitor aminoguanidine and the disease compared to untreated mice.</p> <p>Results</p> <p>Optic nerve head <it>Nos2 </it>RNA levels varied and increased during moderate but decreased at early and severe stages of disease. Despite the presence of a few NOS2 positive cells in the optic nerve head, NOS2 protein was not substantially increased during the glaucoma. Genetic deficiency of <it>Nos2 </it>or aminoguanidine treatment did not alter the IOP profile of DBA/2J mice. Additionally, neither <it>Nos2 </it>deficiency nor aminoguanidine had any detectable affect on the glaucomatous optic nerve damage.</p> <p>Conclusion</p> <p>Glaucomatous neurodegeneration in DBA/2J mice does not require NOS2 activity. Further experiments involving various models are needed to assess the general importance of <it>Nos2 </it>in glaucoma.</p
Infrared Properties of Cataclysmic Variables from 2MASS: Results from the 2nd Incremental Data Release
Because accretion-generated luminosity dominates the radiated energy of most
cataclysmic variables, they have been ``traditionally'' observed primarily at
short wavelengths. Infrared observations of cataclysmic variables contribute to
the understanding of key system components that are expected to radiate at
these wavelengths, such as the cool outer disk, accretion stream, and secondary
star. We have compiled the J, H, and Ks photometry of all cataclysmic variables
located in the sky coverage of the 2 Micron All Sky Survey (2MASS) 2nd
Incremental Data Release. This data comprises 251 systems with reliably
identified near-IR counterparts and S/N > 10 photometry in one or more of the
three near-IR bands.Comment: 2 pages, including 1 figure. To appear in the proceedings of The
Physics of Cataclysmic Variables and Related Objects, Goettingen, Germany.
For our followup ApJ paper (in press), also see
http://www.ctio.noao.edu/~hoard/research/2mass/index.htm
Deep-Sea Fish Distribution Varies between Seamounts: Results from a Seamount Complex off New Zealand
Fish species data from a complex of seamounts off New Zealand termed the “Graveyard Seamount Complex’ were analysed to investigate whether fish species composition varied between seamounts. Five seamount features were included in the study, with summit depths ranging from 748–891 m and elevation from 189–352 m. Measures of fish species dominance, rarity, richness, diversity, and similarity were examined. A number of factors were explored to explain variation in species composition, including latitude, water temperature, summit depth, depth at base, elevation, area, slope, and fishing effort. Depth at base and slope relationships were significant with shallow seamounts having high total species richness, and seamounts with a more gradual slope had high mean species richness. Species similarity was modelled and showed that the explanatory variables were driven primarily by summit depth, as well as by the intensity of fishing effort and elevation. The study showed that fish assemblages on seamounts can vary over very small spatial scales, in the order of several km. However, patterns of species similarity and abundance were inconsistent across the seamounts examined, and these results add to a growing literature suggesting that faunal communities on seamounts may be populated from a broad regional species pool, yet show considerable variation on individual seamounts
Why Um Helps Auditory Word Recognition: The Temporal Delay Hypothesis
Several studies suggest that speech understanding can sometimes benefit from the presence of filled pauses (uh, um, and the like), and that words following such filled pauses are recognised more quickly. Three experiments examined whether this is because filled pauses serve to delay the onset of upcoming words and these delays facilitate auditory word recognition, or whether the fillers themselves serve to signal upcoming delays in a way which informs listeners' reactions. Participants viewed pairs of images on a computer screen, and followed recorded instructions to press buttons corresponding to either an easy (unmanipulated, with a high-frequency name) or a difficult (visually blurred, low-frequency) image. In all three experiments, participants were faster to respond to easy images. In 50% of trials in each experiment, the name of the image was directly preceded by a delay; in the remaining trials an equivalent delay was included earlier in the instruction. Participants were quicker to respond when a name was directly preceded by a delay, regardless of whether this delay was filled with a spoken um, was silent, or contained an artificial tone. This effect did not interact with the effect of image difficulty, nor did it change over the course of each experiment. Taken together, our consistent finding that delays of any kind help word recognition indicates that natural delays such as fillers need not be seen as ‘signals’ to explain the benefits they have to listeners' ability to recognise and respond to the words which follow them
A multidisciplinary approach for generating globally consistent data on mesophotic, deep-pelagic, and bathyal biological communities
Approaches to measuring marine biological parameters remain almost as diverse as the researchers who measure them. However, understanding the patterns of diversity in ocean life over different temporal and geographic scales requires consistent data and information on the potential environmental drivers. As a group of marine scientists from different disciplines, we suggest a formalized, consistent framework of 20 biological, chemical, physical, and socioeconomic parameters that we consider the most important for describing environmental and biological variability. We call our proposed framework the General Ocean Survey and Sampling Iterative Protocol (GOSSIP). We hope that this framework will establish a consistent approach to data collection, enabling further collaboration between marine scientists from different disciplines to advance knowledge of the ocean (deep-sea and mesophotic coral ecosystems)
Becoming an English language teacher:linguistic knowledge, anxieties and the shifting sense of identity
English Language is a fast growing and popular subject at A level but the majority of qualified secondary teachers in the UK have subject expertise and backgrounds in literature. This paper reports on interviews with seven secondary English teachers who discuss the strategies they used when taking on the responsibility of A level English Language teaching for the first time. It highlights the shifting sense of identity that these teachers felt they went through, and as such, explores some emerging issues related to identity from a narrative/personal history perspective. The study reveals that despite feelings of anxiety and low self-confidence, teachers felt that the experience had been a positive one in terms of their own developing identity as an English teacher and had impacted on other aspects of their teaching. The paper raises questions about the value of language-based work for English teachers and has implications for UK initial and continuing teacher education in English
Resolution of hyposmotic stress in isolated mouse ventricular myocytes causes sealing of t‐tubules
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/98789/1/expphysiol.2013.072470.pd
Science Priorities for Seamounts: Research Links to Conservation and Management
Seamounts shape the topography of all ocean basins and can be hotspots of biological activity in the deep sea. The Census of Marine Life on Seamounts (CenSeam) was a field program that examined seamounts as part of the global Census of Marine Life (CoML) initiative from 2005 to 2010. CenSeam progressed seamount science by collating historical data, collecting new data, undertaking regional and global analyses of seamount biodiversity, mapping species and habitat distributions, challenging established paradigms of seamount ecology, developing new hypotheses, and documenting the impacts of human activities on seamounts. However, because of the large number of seamounts globally, much about the structure, function and connectivity of seamount ecosystems remains unexplored and unknown. Continual, and potentially increasing, threats to seamount resources from fishing and seabed mining are creating a pressing demand for research to inform conservation and management strategies. To meet this need, intensive science effort in the following areas will be needed: 1) Improved physical and biological data; of particular importance is information on seamount location, physical characteristics (e.g. habitat heterogeneity and complexity), more complete and intensive biodiversity inventories, and increased understanding of seamount connectivity and faunal dispersal; 2) New human impact data; these shall encompass better studies on the effects of human activities on seamount ecosystems, as well as monitoring long-term changes in seamount assemblages following impacts (e.g. recovery); 3) Global data repositories; there is a pressing need for more comprehensive fisheries catch and effort data, especially on the high seas, and compilation or maintenance of geological and biodiversity databases that underpin regional and global analyses; 4) Application of support tools in a data-poor environment; conservation and management will have to increasingly rely on predictive modelling techniques, critical evaluation of environmental surrogates as faunal “proxies”, and ecological risk assessment
Managed Aquifer Recharge as a Tool to Enhance Sustainable Groundwater Management in California
A growing population and an increased demand for water resources have resulted in a global trend of groundwater depletion. Arid and semi-arid climates are particularly susceptible, often relying on groundwater to support large population centers or irrigated agriculture in the absence of sufficient surface water resources. In an effort to increase the security of groundwater resources, managed aquifer recharge (MAR) programs have been developed and implemented globally. MAR is the approach of intentionally harvesting and infiltrating water to recharge depleted aquifer storage. California is a prime example of this growing problem, with three cities that have over a million residents and an agricultural industry that was valued at 47 billion dollars in 2015. The present-day groundwater overdraft of over 100 km3 (since 1962) indicates a clear disparity between surface water supply and water demand within the state. In the face of groundwater overdraft and the anticipated effects of climate change, many new MAR projects are being constructed or investigated throughout California, adding to those that have existed for decades. Some common MAR types utilized in California include injection wells, infiltration basins (also known as spreading basins, percolation basins, or recharge basins), and low-impact development. An emerging MAR type that is actively being investigated is the winter flooding of agricultural fields using existing irrigation infrastructure and excess surface water resources, known as agricultural MAR. California therefore provides an excellent case study to look at the historical use and performance of MAR, ongoing and emerging challenges, novel MAR applications, and the potential for expansion of MAR. Effective MAR projects are an essential tool for increasing groundwater security, both in California and on a global scale. This chapter aims to provide an overview of the most common MAR types and applications within the State of California and neighboring semi-arid regions
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