221 research outputs found

    A Creek in Need: A Water Chemistry Analysis of a Stream Slated for Restoration (Line Creek, Schoharie County, NY)

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    Surface water quality may directly impact human health and the survival of aquatic life. Schoharie County is a unique laboratory for studying surface water chemistry because many creeks and streams were ravaged by large scale flooding events associated with Hurricane Irene and Tropical Storm Lee in 2011. Currently, one of the largest stream restoration projects in the US is being conducted in the Schoharie Creek watershed. One damaged stream is Line Creek, which is a small first order stream in that watershed. Line Creek was tested for sodium, chloride, alkalinity (HCO3-), hardness (CaCO3), iron, nitrite (NO2-N), nitrate (NO3-N), total and dissolved phosphorous (PO4-P), ammonia (NH3-N) and coliform bacteria. The aforementioned parameters were measured at two sites between February and May 2014 and were compared to earlier data. Data for 2014 (upstream/downstream; all values are mg/L unless otherwise noted) are: sodium 3.18/4.46; chloride 13.5/22.5; alkalinity 29.2/55.0; hardness 40.8/58.8; iron 0.296/0.354; nitrite 0.011/0.014; nitrate 0.122/0.149; total phosphorous 0.002/0.043; dissolved phosphorous 0/0.015; ammonia 0.597/0.639; coliform bacteria(CFU) 16/42. While many parameters fell within EPA guidelines for human consumption or within an accepted range for survival of aquatic life, some like iron, were too high by EPA standards, while alkalinity was too low for aquatic life to properly develop essential hard/bony body structures. This work will be discussed with respect to the larger Schoharie Creek watershed. The broad implications of the data with respect to human and aquatic life will be discussed

    Design approaches and materials processes for ultrahigh efficiency lattice mismatched multi-junction solar cells

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    In this study, we report synthesis of large area (>2cm^2), crack-free GaAs and GaInP double heterostructures grown in a multi-junction solar cell-like structure by MOCVD. Initial solar cell data are also reported for GaInP top cells. These samples were grown on Ge/Si templates fabricated using wafer bonding and ion implantation induced layer transfer techniques. The double heterostructures exhibit radiative emission with uniform intensity and wavelength in regions not containing interfacial bubble defects. The minority carrier lifetime of ~1ns was estimated from photoluminescence decay measurements in both double heterostructures. We also report on the structural characteristics of heterostructures, determined via atomic force microscopy and transmission electron microscopy, and correlate these characteristics to the spatial variation of the minority carrier lifetime

    Neptunium and manganese biocycling in nuclear legacy sediment systems

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    Understanding the behaviour of the highly radiotoxic, long half-life radionuclide neptunium in the environment is important for the management of radioactively contaminated land and the safe disposal of radioactive wastes. Recent studies have identified that microbial reduction can reduce the mobility of neptunium via reduction of soluble Np(V) to poorly soluble Np(IV), with coupling to both Mn- and Fe(III)- reduction implicated in neptunyl reduction. To further explore these processes Mn(IV) as δMnO2 was added to sediment microcosms to create a sediment microcosm experiment "poised" under Mn-reducing conditions. Enhanced removal of Np(V) from solution occurred during Mn-reduction, and parallel X-ray absorption spectroscopy (XAS) studies confirmed Np(V) reduction to Np(IV) commensurate with microbially-mediated Mn-reduction. Molecular ecology analysis of the XAS systems, which contained up to 0.2 mM Np showed no significant impact of elevated Np concentrations on the microbial population. These results demonstrate the importance of Mn cycling on Np biogeochemistry, and clearly highlight new pathways to reductive immobilisation for this highly radiotoxic actinide

    GaInP/GaAs dual junction solar cells on Ge/Si epitaxial templates

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    In this study, we report synthesis of large area (> 2 cm^2) crack-free GaInP/GaAs double junction solar cells on 50 mm diameter Ge/Si templates fabricated using wafer bonding and ion implantation induced layer transfer techniques. Defect removal from the template film and film surface prior to epitaxial growth was found to be critical to achievement of high open circuit voltage and efficiency. Cells grown on templates prepared with chemical mechanical polishing in addition a wet chemical etch show comparable performance to control devices grown on bulk Ge substrates. Current-voltage (I–V) data under AM 1.5 illumination indicate that the short circuit current is comparable in templated and control cells, but the open circuit voltage is slightly lower (2.08V vs. 2.16V). Spectral response measurements indicate a drop in open circuit voltage due to a slight lowering of the top GaInP cell band gap. The drop in band gap is due to a difference in the indium composition in the two samples caused by the different miscut (9° vs. 6°) of the two kinds of substrates

    Active citizenship and aquired neurological communication difficulty

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    People with communication impairments may face barriers to civic participation, with resulting marginalisation of individuals who wish to be actively involved. The investigation aimed to explore the experience of civically engaged adults with acquired neurological communication difficulties. Six people with acquired neurological communication difficulties were interviewed. Discussion included the definition of active citizenship, their civic involvement, motivations, related barriers and facilitators. Qualitative analysis was undertaken, with data categorised, coded and examined for recurring themes. All participants were active in disability-related organisations and four undertook wider civic roles. Motivations included activity being outwith the home and wanting to effect change for themselves and the populations they represented. Disability group meetings were more positive experiences than broader community activities, which were associated with fatigue and frustration, commonly resulting from communication difficulties and unmet support needs. All participants identified a need for professional and public educational about disability and communication and made recommendations on content, methods and priority groups. For these participants civic engagement had positive and negative dimensions. Speech and language therapists should promote reduction of the barriers that impede the active citizenship rights of people with communication support needs. Civic participation may be a relevant measure of outcome in communication impaired populations

    Tankyrase represses autoinflammation through the attenuation of TLR2 signaling

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    Dysregulation of Toll-like receptor (TLR) signaling contributes to the pathogenesis of autoimmune diseases. Here, we provide genetic evidence that tankyrase, a member of the poly(ADP-ribose) polymerase (PARP) family, negatively regulates TLR2 signaling. We show that mice lacking tankyrase in myeloid cells developed severe systemic inflammation with high serum inflammatory cytokine levels. We provide mechanistic evidence that tankyrase deficiency resulted in tyrosine phosphorylation and activation of TLR2 and show that phosphorylation of tyrosine 647 within the TIR domain by SRC and SYK kinases was critical for TLR2 stabilization and signaling. Last, we show that the elevated cytokine production and inflammation observed in mice lacking tankyrase in myeloid cells were dependent on the adaptor protein 3BP2, which is required for SRC and SYK activation. These data demonstrate that tankyrase provides a checkpoint on the TLR-mediated innate immune response

    GaInP/GaAs dual junction solar cells on Ge/Si epitaxial templates

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    In this study, we report synthesis of large area (> 2 cm^2) crack-free GaInP/GaAs double junction solar cells on 50 mm diameter Ge/Si templates fabricated using wafer bonding and ion implantation induced layer transfer techniques. Defect removal from the template film and film surface prior to epitaxial growth was found to be critical to achievement of high open circuit voltage and efficiency. Cells grown on templates prepared with chemical mechanical polishing in addition a wet chemical etch show comparable performance to control devices grown on bulk Ge substrates. Current-voltage (I–V) data under AM 1.5 illumination indicate that the short circuit current is comparable in templated and control cells, but the open circuit voltage is slightly lower (2.08V vs. 2.16V). Spectral response measurements indicate a drop in open circuit voltage due to a slight lowering of the top GaInP cell band gap. The drop in band gap is due to a difference in the indium composition in the two samples caused by the different miscut (9° vs. 6°) of the two kinds of substrates

    Evaluation of ground-level and space-borne sensor as tools in monitoring nitrogen nutrition status in immature and mature oil palm

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    Monitoring nitrogen (N) in oil palm is crucial for the production sustainability. The objective of this study is to examine the capability of visible (Vis), near infrared (NIR) and a combination of Vis and NIR (Vis + NIR) spectral indices acquired from different sensors for predicting foliar N content of different palm age groups. The N treatments varied from 0 to 2 kg per palm, subjected according to immature, young mature and prime mature classes. The Vis + NIR indices from the ground level-sensor that is green + red + NIR (G + R + NIR) was the best index for predicting N for immature palms (R2 = 0.91), while Vis indices blue + red (B + R) and Green Red Index from the space-borne sensor were significantly useful for N assessment of young and prime mature palms (R2 = 0.70 and 0.50), respectively. The application of vegetation indices for monitoring N status of oil palm is beneficial to examine extensive plantation areas

    GaInP/GaAs dual junction solar cells on Ge/Si epitaxial templates

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    Large area, crack-free GaInP/GaAs double junction solar cells were grown by metal organic chemical vapor deposition on Ge/Si templates fabricated using wafer bonding and ion implantation induced layer transfer. Photovoltaic performance of these devices was comparable to those grown on bulk epi-ready Ge, demonstrating the feasibility of alternative substrates fabricated via wafer bonding and layer transfer for growth of active devices on lattice mismatched substrates
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