3,909 research outputs found

    Differential effects of \u3ci\u3eCdh23\u3csup\u3e753A\u3c/sup\u3e\u3c/i\u3e on auditory and vestibular functional aging in C57BL/6J mice

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    The C57BL/6J (B6) mouse strain carries a cadherin 23 mutation (Cdh23753A, also known as Ahl), which affects inner ear structures and results in age-related hearing loss. The B6.CAST strain harbors the wild type Cdh23 gene, and hence, the influence of Ahl is absent. The purpose of the present study was to characterize the effect of age and gender on gravity receptor function in B6 and B6.CAST strains and to compare functional aging between auditory and vestibular modalities. Auditory sensitivity declined at significantly faster rates than gravity receptor sensitivity for both strains. Indeed, vestibular functional aging was minimal for both strains. The comparatively smaller loss of macular versus cochlear sensitivity in both the B6 and B6.CAST strains suggests that the contribution of Ahl to the aging of the vestibular system is minimal, and thus very different than its influence on aging of the auditory system. Alternatively, there exist unidentified genes or gene modifiers that serve to slow the degeneration of gravity receptor structures and maintain gravity receptor sensitivity into advanced age

    Dose-Duration Reciprocity for G protein activation: Modulation of kinase to substrate ratio alters cell signaling

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    In animal cells, activation of heterotrimeric G protein signaling generally occurs when the system’s cognate signal exceeds a threshold, whereas in plant cells, both the amount and the exposure time of at least one signal, D-glucose, are used toward activation. This unusual signaling property called Dose-Duration Reciprocity, first elucidated in the genetic model Arabidopsis thaliana, is achieved by a complex that is comprised of a 7-transmembrane REGULATOR OF G SIGNALING (RGS) protein (AtRGS1), a Gα subunit that binds and hydrolyzes nucleotide, a Gβγ dimer, and three WITH NO LYSINE (WNK) kinases. D-glucose is one of several signals such as salt and pathogen-derived molecular patterns that operates through this protein complex to activate G protein signaling by WNK kinase transphosphorylation of AtRGS1. Because WNK kinases compete for the same substrate, AtRGS1, we hypothesize that activation is sensitive to the AtRGS1 amount and that modulation of the AtRGS1 pool affects the response to the stimulant. Mathematical simulation revealed that the ratio of AtRGS1 to the kinase affects system sensitivity to D-glucose, and therefore illustrates how modulation of the cellular AtRGS1 level is a means to change signal-induced activation. AtRGS1 levels change under tested conditions that mimic physiological conditions therefore, we propose a previously-unknown mechanism by which plants react to changes in their environment

    Evaluating Native American Bird Use and Bird Assemblage Variability along the Oregon Coast

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    Native American use of birds on the Oregon coast is not well known and has never been synthesized to present a regional understanding. We rectify this by analyzing data from 26 zooarchaeological assemblages, including three previously unpublished bird assemblages: Umpqua/Eden (35DO83), Whale Cove (35LNC60), and the Dunes Site (35CLT27). We employ a series of non-parametric randomization tests to directly evaluate patterns of taxonomic diversity, correlations with nearby breeding colonies, and broader procurement strategies discussed in ethnohistorical accounts. We compare the assemblages to contemporary surveys of naturally beached birds as observed by COASST (Coastal Observation Seabird Survey Team) and evaluate whether archaeological specimens were scavenged from the beach. While 71% of the identified bird remains belong to just three families (Anatidae, Alcidae, and Procellariidae), closer analysis reveals the incredible diversity of birds used by Oregon coast Native Americans. The assemblages vary considerably in terms of taxonomic diversity and composition, leading us to conclude that people used birds opportunistically, likely incorporating multiple strategies, including hunting, collecting beached carcasses and targeting cormorant colonies. We hope that the methods and approaches employed here will inspire other archaeologists to devote more attention to bird assemblages, and how their study can inform conservation efforts

    Experimental requirements for Grover's algorithm in optical quantum computation

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    The field of linear optical quantum computation (LOQC) will soon need a repertoire of experimental milestones. We make progress in this direction by describing several experiments based on Grover's algorithm. These experiments range from a relatively simple implementation using only a single non-scalable CNOT gate to the most complex, requiring two concatenated scalable CNOT gates, and thus form a useful set of early milestones for LOQC. We also give a complete description of basic LOQC using polarization-encoded qubits, making use of many simplifications to the original scheme of Knill, Laflamme, and Milburn.Comment: 9 pages, 8 figure

    Are any coastal internal tides predictable?

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    Author Posting. © The Oceanography Society, 2012. This article is posted here by permission of The Oceanography Society for personal use, not for redistribution. The definitive version was published in Oceanography 25, No. 2 (2012): 80-95, doi:10.5670/oceanog.2012.44.Surface tides are the heartbeat of the ocean. Because they are controlled by Earth's motion relative to other astronomical objects in our solar system, surface tides act like clockwork and generate highly deterministic ebb and flow familiar to all mariners. In contrast, baroclinic motions at tidal frequencies are much more stochastic, owing to complexities in how these internal motions are generated and propagate. Here, we present analysis of current records from continental margins worldwide to illustrate that coastal internal tides are largely unpredictable. This conclusion has numerous implications for coastal processes, as across-shelf exchange and vertical mixing are, in many cases, strongly influenced by the internal wave field.This work was supported through grants from the US Office of Naval Research and NSF (Nash, Shroyer, Musgrave, Levine, and Duda), by NERC (grant NE/IO30224/1 FASTNEt; Inall), and by AIMS/CSIRO (Kelly and Jones)

    Mapping the cis-regulatory architecture of the human retina reveals noncoding genetic variation in disease

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    The interplay of transcription factors and cis-regulatory elements (CREs) orchestrates the dynamic and diverse genetic programs that assemble the human central nervous system (CNS) during development and maintain its function throughout life. Genetic variation within CREs plays a central role in phenotypic variation in complex traits including the risk of developing disease. We took advantage of the retina, a well-characterized region of the CNS known to be affected by pathogenic variants in CREs, to establish a roadmap for characterizing regulatory variation in the human CNS. This comprehensive analysis of tissue-specific regulatory elements, transcription factor binding, and gene expression programs in three regions of the human visual system (retina, macula, and retinal pigment epithelium/choroid) reveals features of regulatory element evolution that shape tissue-specific gene expression programs and defines regulatory elements with the potential to contribute to Mendelian and complex disorders of human vision

    Hurricane Imaging Radiometer (HIRAD) Observations of Brightness Temperatures and Ocean Surface Wind Speed and Rain Rate During NASA's GRIP and HS3 Campaigns

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    HIRAD flew on high-altitude aircraft over Earl and Karl during NASA s GRIP (Genesis and Rapid Intensification Processes) campaign in August - September of 2010, and plans to fly over Atlantic tropical cyclones in September of 2012 as part of the Hurricane and Severe Storm Sentinel (HS3) mission. HIRAD is a new C-band radiometer using a synthetic thinned array radiometer (STAR) technology to obtain spatial resolution of approximately 2 km, out to roughly 30 km each side of nadir. By obtaining measurements of emissions at 4, 5, 6, and 6.6 GHz, observations of ocean surface wind speed and rain rate can be retrieved. The physical retrieval technique has been used for many years by precursor instruments, including the Stepped Frequency Microwave Radiometer (SFMR), which has been flying on the NOAA and USAF hurricane reconnaissance aircraft for several years to obtain observations within a single footprint at nadir angle. Results from the flights during the GRIP and HS3 campaigns will be shown, including images of brightness temperatures, wind speed, and rain rate. Comparisons will be made with observations from other instruments on the campaigns, for which HIRAD observations are either directly comparable or are complementary. Features such as storm eye and eye-wall, location of storm wind and rain maxima, and indications of dynamical features such as the merging of a weaker outer wind/rain maximum with the main vortex may be seen in the data. Potential impacts on operational ocean surface wind analyses and on numerical weather forecasts will also be discussed
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