312 research outputs found

    Global SOC, Annual NPP & CO2 Turnover Time (Ď„)

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    Interlinked issues of global soil organic carbon (SOC), annual net primary productivity (NPP) and atmospheric CO2 turnover time (τ) are updated. Soil is confirmed as both the greatest sink and source for excess atmospheric CO2. Most terrestrial NPP (~218 Gt C/yr) is ultimately processed in topsoil and SOC stocks now total >10,000–12,000 Gt. More excess carbon is released into the air and water from SOC loss (>20 Gt C/yr) due to land clearance for pasture/crops, fires, agrichemical poisoning and erosion, than from fossil fuels (~10 Gt C/yr). NOAA’s Barrow bounce and isotopic analyses support high terrestrial flux up to ~800 Gt C/yr and CO2 turnover time of ~1–4 years. Earth’s re-humification via compost in organic farming offers the best and only practical/time-critical fix for climate, strategy for species extinction plus a remedy for human health

    A comparison of scores of negro and white children on the Wechsler Intelligence Scale for Children

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    This investigation concerns the intelligence of the Negro population in relation to the white population. There is a considerable difference of opinion relating to the intelligence of the Negro. Some students in the field contend that the Negro\u27s intelligence, as measured by the tests available for all individuals, is naturally lower due to hereditary factors. Other investigators (these seem to be in the majority1 believe that environment plays the major role in lowering their ability to gain a comparable score with white individuals

    Race, Gender, Occupational Status, And Income In County Human Service Employment

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    Data obtained from more than 1,900 public welfare workers employed in five regions of the country were examined to compare occupational status and earnings by race and gender. The study group was stratified so that respondents\u27 educational attainment and job seniority levels could be taken into account. Findings indicate the presence of significant sex and race-linked differences

    Stability and conformation of the dimeric HIV-1 genomic RNA 5\u27UTR

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    During HIV-1 assembly, the viral Gag polyprotein specifically selects the dimeric RNA genome for packaging into new virions. The 5\u27 untranslated region (5\u27UTR) of the dimeric genome may adopt a conformation that is optimal for recognition by Gag. Further conformational rearrangement of the 5\u27UTR, promoted by the nucleocapsid (NC) domain of Gag, is predicted during virus maturation. Two 5\u27UTR dimer conformations, the kissing dimer (KD) and the extended dimer (ED), have been identified in vitro, which differ in the extent of intermolecular basepairing. Whether 5\u27UTRs from different HIV-1 strains with distinct sequences have access to the same dimer conformations has not been determined. Here, we applied fluorescence cross-correlation spectroscopy and single-molecule Forster resonance energy transfer imaging to demonstrate that 5\u27UTRs from two different HIV-1 subtypes form (KDs) with divergent stabilities. We further show that both 5\u27UTRs convert to a stable dimer in the presence of the viral NC protein, adopting a conformation consistent with extensive intermolecular contacts. These results support a unified model in which the genomes of diverse HIV-1 strains adopt an ED conformation

    Anodic deposition of a robust iridium-based water-oxidation catalyst from organometallic precursors

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    Artificial photosynthesis, modeled on natural light-driven oxidation of water in Photosystem II, holds promise as a sustainable source of reducing equivalents for producing fuels. Few robust water-oxidation catalysts capable of mediating this difficult four-electron, four-proton reaction have yet been described. We report a new method for generating an amorphous electrodeposited material, principally consisting of iridium and oxygen, which is a robust and long-lived catalyst for water oxidation, when driven electrochemically. The catalyst material is generated by a simple anodic deposition from Cp*Ir aqua or hydroxo complexes in aqueous solution. This work suggests that organometallic precursors may be useful in electrodeposition of inorganic heterogeneous catalysts

    Light localization induced enhancement of third order nonlinearities in a GaAs photonic crystal waveguide

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    Nonlinear propagation experiments in GaAs photonic crystal waveguides (PCW) were performed, which exhibit a large enhancement of third order nonlinearities, due to light propagation in a slow mode regime, such as two-photon absorption (TPA), optical Kerr effect and refractive index changes due to TPA generated free-carriers. A theoretical model has been established that shows very good quantitative agreement with experimental data and demonstrates the important role that group velocity plays. These observations give a strong insight into the use of PCWs for optical switching devices.Comment: 6 page

    Safety and feasibility of oral immunotherapy to multiple allergens for food allergy

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    BACKGROUND: Thirty percent of children with food allergy are allergic to more than one food. Previous studies on oral immunotherapy (OIT) for food allergy have focused on the administration of a single allergen at the time. This study aimed at evaluating the safety of a modified OIT protocol using multiple foods at one time. METHODS: Participants underwent double-blind placebo-controlled food challenges (DBPCFC) up to a cumulative dose of 182 mg of food protein to peanut followed by other nuts, sesame, dairy or egg. Those meeting inclusion criteria for peanut only were started on single-allergen OIT while those with additional allergies had up to 5 foods included in their OIT mix. Reactions during dose escalations and home dosing were recorded in a symptom diary. RESULTS: Forty participants met inclusion criteria on peanut DBPCFC. Of these, 15 were mono-allergic to peanut and 25 had additional food allergies. Rates of reaction per dose did not differ significantly between the two groups (median of 3.3% and 3.7% in multi and single OIT group, respectively; p = .31). In both groups, most reactions were mild but two severe reactions requiring epinephrine occurred in each group. Dose escalations progressed similarly in both groups although, per protocol design, those on multiple food took longer to reach equivalent doses per food (median +4 mo.; p < .0001). CONCLUSIONS: Preliminary data show oral immunotherapy using multiple food allergens simultaneously to be feasible and relatively safe when performed in a hospital setting with trained personnel. Additional, larger, randomized studies are required to continue to test safety and efficacy of multi-OIT. TRIAL REGISTRATION: Clinicaltrial.gov NCT0149017

    Performance of the G4 Xpert(R) MTB/RIF assay for the detection of Mycobacterium tuberculosis and rifampin resistance: a retrospective case-control study of analytical and clinical samples from high- and low-tuberculosis prevalence settings

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    BACKGROUND: The Xpert(R) MTB/RIF (Xpert) assay is a rapid PCR-based assay for the detection of Mycobacterium tuberculosis complex DNA (MTBc) and mutations associated with rifampin resistance (RIF). An updated version introduced in 2011, the G4 Xpert, included modifications to probe B and updated analytic software. METHODS: An analytical study was performed to assess Xpert detection of mutations associated with rifampin resistance in rifampin-susceptible and -resistant isolates. A clinical study was performed in which specimens from US and non-US persons suspected of tuberculosis (TB) were tested to determine Xpert performance characteristics. All specimens underwent smear microscopy, mycobacterial culture, conventional drug-susceptibility testing and Xpert testing; DNA from isolates with discordant rifampin resistance results was sequenced. RESULTS: Among 191 laboratory-prepared isolates in the analytical study, Xpert sensitivity for detection of rifampin resistance associated mutations was 97.7% and specificity was 90.8%, which increased to 99.0% after DNA sequencing analysis of the discordant samples. Of the 1,096 subjects in the four clinical studies, 49% were from the US. Overall, Xpert detected MTBc in 439 of 468 culture-positive specimens for a sensitivity of 93.8% (95% confidence interval [CI]: 91.2%-95.7%) and did not detect MTBc in 620 of 628 culture-negative specimens for a specificity of 98.7% (95% CI: 97.5%-99.4%). Sensitivity was 99.7% among smear-positive cases, and 76.1% among smear-negative cases. Non-determinate MTBc detection and false-positive RIF resistance results were low (1.2 and 0.9%, respectively). CONCLUSIONS: The updated Xpert assay retained the high sensitivity and specificity of the previous assay versions and demonstrated low rates of non-determinate and RIF resistance false positive results

    Electrocatalysis of CO_2 Reduction in Brush Polymer Ion Gels

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    The electrochemical characterization of brush polymer ion gels containing embedded small-molecule redox-active species is reported. Gels comprising PS–PEO–PS triblock brush polymer, 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (BMIm-TFSI), and some combination of ferrocene (Fc), cobaltocenium (CoCp_2^+), and Re(bpy)(CO)_3Cl (1) exhibit diffusion-controlled redox processes with diffusion coefficients approximately one-fifth of those observed in neat BMIm-TFSI. Notably, 1 dissolves homogeneously in the interpenetrating matrix domain of the ion gel and displays electrocatalytic CO_2 reduction to CO in the gel. The catalytic wave exhibits a positive shift versus Fc^(+/0) compared with analogous nonaqueous solvents with a reduction potential 450 mV positive of onset and 90% Faradaic efficiency for CO production. These materials provide a promising and alternative approach to immobilized electrocatalysis, creating numerous opportunities for application in solid-state devices
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