4,445 research outputs found

    A High Elevation Record of the Star-nosed Mole (Condylura cristata) in Northeastern Vermont

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    A single male Star-nosed Mole, Condylura cristata, was captured in a rock pile at the top of East Mountain (elevation 1042 m; 3240 ft) in northeastern Vermont. Although known from high elevations (up to 1676 m; 5500 ft) in southern U.S. states, this species was not known to occur above 573 m (1880 ft) in the northern part of its range. This record is also important in confirming that C. cristata has some climbing ability when travelling above ground

    The Naval Night Battles in the Solomons

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    Direct observation of yield in films by flat punch indentation

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    In regular indentation many strain states are simultaneously present in the indented region, so measured parameters such as hardness and modulus are average values over a wide range of strains. Testing of structures such as pillars, levers or film bulges enables determination of yield point and modulus with uniform strains in the sample, but requires specialised sample preparation and can be significantly affected by surface condition. Here we show how in-situ indentation with a flat punch allows direct observation of a discrete yield point in soft films on more rigid substrates. The yield point is clearly observable from the load displacement behaviour and from post indent AFM imaging. The film is in uniform uniaxial strain. Finite element simulations show that effective self-confinement by surrounding film material leads to uniformity throughout the film material down to surprisingly low aspect ratios around 4:1. This occurs for a significant range of stresses above the yield point. Eventually at even higher stresses the film material is extruded laterally. The characteristics of the yield event will be described as a function of temperature and film thickness for thin to ultrathin films. At higher aspect ratio and with sufficient stiffness of punch and substrate, quantitative, in-situ measurement of intrinsic stress vs. strain to well beyond the elastic limit becomes possible for thin films. The extent to which full constitutive relations for polymer films can be determied will be discussed, along with limitations of the technique

    3',5'-Cyclic Adenosine Monophosphate- and Ca2+-Calmodulin-Dependent Endogenous Protein Phosphorylation Activity in Membranes of the Bovine Chromaffin Secretory Vesicles: Identification of Two Phosphorylated Components as Tyrosine Hydroxylase and Protein Kinase Regulatory Subunit Type II

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    Abstract: Membranes of the secretory vesicles from bovine adrenal medulla were investigated for the presence of the endogenous protein phosphorylation activity. Seven phosphoprotein bands in the molecular weight range of 250,000 to 30,000 were observed by means of the sodium dodecyl sulphate electrophoresis and autoradiography. On the basis of the criteria of molecular weight, selective stimulation of the phosphorylation by cyclic AMP (as compared with cyclic GMP) and immunoprecipitation by specific antibodies, band 5 (molecular weight 60,300) was found to represent the phosphorylated form of the secretory vesicle-bound tyrosine hydroxylase. The electrophoretic mobility, the stimulatory and inhibitory effects of cyclic AMP in presence of Mg2+ and Zn,2+ respectively, and immunoreactivity toward antibodies showed band 6 to contain two forms of the regulatory subunits of the type II cyclic AMP-dependent protein kinase, distinguishable by their molecular weights (56,000 and 52,000, respectively). Phosphorylation of band 7 (molecular weight 29,800) was stimulated about 2 to 3 times by Ca2+ and calmodulin in the concentration range of both agents believed to occur in the secretory tissues under physiological conditions

    The NIDDK Central Repository at 8 years—Ambition, Revision, Use and Impact

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    The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) Central Repository makes data and biospecimens from NIDDK-funded research available to the broader scientific community. It thereby facilitates: the testing of new hypotheses without new data or biospecimen collection; pooling data across several studies to increase statistical power; and informative genetic analyses using the Repository’s well-curated phenotypic data. This article describes the initial database plan for the Repository and its revision using a simpler model. Among the lessons learned were the trade-offs between the complexity of a database design and the costs in time and money of implementation; the importance of integrating consent documents into the basic design; the crucial need for linkage files that associate biospecimen IDs with the masked subject IDs used in deposited data sets; and the importance of standardized procedures to test the integrity data sets prior to distribution. The Repository is currently tracking 111 ongoing NIDDK-funded studies many of which include genotype data, and it houses over 5 million biospecimens of more than 25 types including serum, plasma, stool, urine, DNA, red blood cells, buffy coat and tissue. Repository resources have supported a range of biochemical, clinical, statistical and genetic research (188 external requests for clinical data and 31 for biospecimens have been approved or are pending). Genetic research has included GWAS, validation studies, development of methods to improve statistical power of GWAS and testing of new statistical methods for genetic research. We anticipate that the future impact of the Repository’s resources on biomedical research will be enhanced by (i) cross-listing of Repository biospecimens in additional searchable databases and biobank catalogs; (ii) ongoing deployment of new applications for querying the contents of the Repository; and (iii) increased harmonization of procedures, data collection strategies, questionnaires etc. across both research studies and within the vocabularies used by different repositories

    Reactivity of a dititanium bis(pentalene) complex toward heteroallenes and main-group element–element bonds

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    The reactivity of the Ti═Ti double bond in (μ,η5:η5-Pn†)2Ti2 (1; Pn† = 1,4-{SiiPr3}2C8H4) toward isocyanide and heteroallene substrates, and molecules featuring homonuclear bonds between main-group elements (E–E) has been explored. Reaction of 1 with methyl isocyanide or 1,3-N,N′-di-p-tolylcarbodiimide resulted in the formation of the 1:1 adducts (μ,η5:η5-Pn†)2Ti2(μ,η2-CNMe) (2) and (μ,η5:η5-Pn†)2Ti2(μ-C{N(4-C6H4CH3)}2) (3), respectively, which are thermally stable up to 100 °C in contrast to the analogous adducts formed with CO and CO2. Reaction of 1 with phenyl isocyanate afforded a paramagnetic complex, [(η8-Pn†)Ti]2(μ,κ2:κ2-O2CNPh) (4), in which the “double-sandwich” architecture of 1 has been broken and an unusual phenyl-carbonimidate ligand bridges two formally Ti(III) centers. Reaction of 1 with diphenyl dichalcogenides, Ph2E2 (E = S, Se, Te), led to the series of Ti–Ti single-bonded complexes (μ,η5:η5-Pn†)2[Ti(EPh)]2 (E = S (5), Se (6), Te (7)), which can be considered the result of a 2e– redox reaction or a 1,2-addition across the Ti═Ti bond. Treatment of 1 with azobenzene or phenyl azide afforded [(η8-Pn†)Ti]2(μ-NPh)2 (8), a bridging imido complex in which the pentalene ligands bind in an η8 fashion to each formally Ti(IV) center, as the result of a 4e– redox reaction driven by the oxidative cleavage of the Ti═Ti double bond. The new complexes 2–8 were extensively characterized by various techniques including multinuclear NMR spectroscopy and single-crystal X-ray diffraction, and the experimental work was complemented by density functional theory (DFT) studies

    The Foundation Supernova Survey: Measuring Cosmological Parameters with Supernovae from a Single Telescope

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    Measurements of the dark energy equation-of-state parameter, ww, have been limited by uncertainty in the selection effects and photometric calibration of z<0.1z<0.1 Type Ia supernovae (SNe Ia). The Foundation Supernova Survey is designed to lower these uncertainties by creating a new sample of z<0.1z<0.1 SNe Ia observed on the Pan-STARRS system. Here, we combine the Foundation sample with SNe from the Pan-STARRS Medium Deep Survey and measure cosmological parameters with 1,338 SNe from a single telescope and a single, well-calibrated photometric system. For the first time, both the low-zz and high-zz data are predominantly discovered by surveys that do not target pre-selected galaxies, reducing selection bias uncertainties. The z>0.1z>0.1 data include 875 SNe without spectroscopic classifications and we show that we can robustly marginalize over CC SN contamination. We measure Foundation Hubble residuals to be fainter than the pre-existing low-zz Hubble residuals by 0.046±0.0270.046 \pm 0.027 mag (stat+sys). By combining the SN Ia data with cosmic microwave background constraints, we find w=0.938±0.053w=-0.938 \pm 0.053, consistent with Λ\LambdaCDM. With 463 spectroscopically classified SNe Ia alone, we measure w=0.933±0.061w=-0.933\pm0.061. Using the more homogeneous and better-characterized Foundation sample gives a 55% reduction in the systematic uncertainty attributed to SN Ia sample selection biases. Although use of just a single photometric system at low and high redshift increases the impact of photometric calibration uncertainties in this analysis, previous low-zz samples may have correlated calibration uncertainties that were neglected in past studies. The full Foundation sample will observe up to 800 SNe to anchor the LSST and WFIRST Hubble diagrams.Comment: 30 pages, 17 figures, accepted by Ap

    Light Curves of the Neutron Star Merger GW170817/SSS17a: Implications for R-Process Nucleosynthesis

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    On 2017 August 17, gravitational waves were detected from a binary neutron star merger, GW170817, along with a coincident short gamma-ray burst, GRB170817A. An optical transient source, Swope Supernova Survey 17a (SSS17a), was subsequently identified as the counterpart of this event. We present ultraviolet, optical and infrared light curves of SSS17a extending from 10.9 hours to 18 days post-merger. We constrain the radioactively-powered transient resulting from the ejection of neutron-rich material. The fast rise of the light curves, subsequent decay, and rapid color evolution are consistent with multiple ejecta components of differing lanthanide abundance. The late-time light curve indicates that SSS17a produced at least ~0.05 solar masses of heavy elements, demonstrating that neutron star mergers play a role in r-process nucleosynthesis in the Universe.Comment: Accepted to Scienc
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