4,368 research outputs found

    Annotated bibliography of observations on Illinois water resources 1673-1850

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    This study is concerned with the development of the water resources to the middle of the nineteenth century. The works involved in it are the French accounts of their travels in the Illinois Country in the seventeenth and early eighteenth centuries; the accounts of the later eighteenth century, during the British period (1763-1783) when the Northwest was closed by royal proclamation to settlement; and the accounts of the nineteenth century when settlement began, primarily in the southern part of the State and, less formally, in the lead region of the northwest corner. By the middle of the century, Illinois reached the stage of sophisticated development; the Federal lands in the State had, almost all been entered, and the frontier had moved westward. An introductory text illustrates the nature of the findings, both as to observations, as well as the influence of the resources themselves, on the growth of the State of Illinois. An extensively annotated bibliography consists of travel narratives and descriptive accounts of Illinois written by observers who were in the State or who wrote of the State between the years 1673 and 1850. These limits were chosen because the first recorded European set foot on Illinois soil in 1673, and after the middle of the nineteenth century the official State and Federal geological reports can be relied upon. The works included in this list were chosen because the authors of them recorded observations bearing on the state of the water resources in Illinois at the time of their visits or publication. The entries in the bibliography consist of the titles, an introductory and summary paragraph, and the pertinent selections from the works.U.S. Department of the InteriorU.S. Geological SurveyOpe

    Radio Astronomy

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    Contains reports on five research projects.National Aeronautics and Space Administration (Grant NGL 22-009-016)National Science Foundation (Grant GP-14854)Joint Services Electronics Programs (U. S. Army, U. S. Navy, and U. S. Air Force) under Contract DA 28-043-AMC-02536(E)National Science Foundation (Grant GP-13056

    Magnetoconductivity of Hubbard bands induced in Silicon MOSFETs

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    Sodium impurities are diffused electrically to the oxide-semiconductor interface of a silicon MOSFET to create an impurity band. At low temperature and at low electron density, the band is split into an upper and a lower sections under the influence of Coulomb interactions. We used magnetoconductivity measurements to provide evidence for the existence of Hubbard bands and determine the nature of the states in each band.Comment: In press in Physica

    Perovskite-perovskite tandem photovoltaics with optimized bandgaps

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    We demonstrate four and two-terminal perovskite-perovskite tandem solar cells with ideally matched bandgaps. We develop an infrared absorbing 1.2eV bandgap perovskite, FA0.75Cs0.25Sn0.5Pb0.5I3FA_{0.75}Cs_{0.25}Sn_{0.5}Pb_{0.5}I_3, that can deliver 14.8 % efficiency. By combining this material with a wider bandgap FA0.83Cs0.17Pb(I0.5Br0.5)3FA_{0.83}Cs_{0.17}Pb(I_{0.5}Br_{0.5})_3 material, we reach monolithic two terminal tandem efficiencies of 17.0 % with over 1.65 volts open-circuit voltage. We also make mechanically stacked four terminal tandem cells and obtain 20.3 % efficiency. Crucially, we find that our infrared absorbing perovskite cells exhibit excellent thermal and atmospheric stability, unprecedented for Sn based perovskites. This device architecture and materials set will enable 'all perovskite' thin film solar cells to reach the highest efficiencies in the long term at the lowest costs

    Persistently Altered Brain Mitochondrial Bioenergetics After Apparently Successful Resuscitation From Cardiac Arrest

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    Background Although advances in cardiopulmonary resuscitation have improved survival from cardiac arrest (CA), neurologic injury persists and impaired mitochondrial bioenergetics may be critical for targeted neuroresuscitation. The authors sought to determine if excellent cardiopulmonary resuscitation and postresuscitation care and good traditional survival rates result in persistently disordered cerebral mitochondrial bioenergetics in a porcine pediatric model of asphyxia‐associated ventricular fibrillation CA. Methods and Results After 7 minutes of asphyxia, followed by ventricular fibrillation, 5 female 1‐month‐old swine (4 sham) received blood pressure–targeted care: titration of compression depth to systolic blood pressure of 90 mm Hg and vasopressor administration to a coronary perfusion pressure \u3e20 mm Hg. All animals received protocol‐based vasopressor support after return of spontaneous circulation for 4 hours before they were killed. The primary outcome was integrated mitochondrial electron transport system (ETS) function. CA animals displayed significantly decreased maximal, coupled oxidative phosphorylating respiration (OXPHOSCI+CII) in cortex (PPPPCI PCII PCIPCII PCI+CII), as well as a 30% reduction in citrate synthase activity (P\u3c0.04). Conclusions Mitochondria in both the cortex and hippocampus displayed significant alterations in respiratory function after CA despite excellent cardiopulmonary resuscitation and postresuscitation care in asphyxia‐associated ventricular fibrillation CA. Analysis of integrated ETS function identifies mitochondrial bioenergetic failure as a target for goal‐directed neuroresuscitation after CA. IACUC Protocol: IAC 13‐001023

    An Architecture for Multi-User Software Development Environments

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    We present an architecture for multi-user software development environments, covering general, process-centered and rule-based MUSDEs. Our architecture is founded on componentization, with particular concern for the capability to replace the synchronization component - to allow experimentation with novel concurrency control mechanisms - with minimal effects on other components while still supporting integration. The architecture has been implemented in the MARVEL SD

    Radio Astronomy

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    Contains research objectives, summary of research and reports on eleven research projects.National Aeronautics and Space Administration (Grant NGL 22-009-016)National Science Foundation (Grant GP-14854)Joint Services Electronics Programs (U. S. Army, U. S. Navy, and U. S. Air Force) under Contract DA 28-043-AMC-02536(E)National Science Foundation (Grant GP-13056)Sloan Fund for Basic Research (M. I. T. Grant 312

    Systematic review and meta-analysis of the diagnostic accuracy of ultrasonography for deep vein thrombosis

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    Background Ultrasound (US) has largely replaced contrast venography as the definitive diagnostic test for deep vein thrombosis (DVT). We aimed to derive a definitive estimate of the diagnostic accuracy of US for clinically suspected DVT and identify study-level factors that might predict accuracy. Methods We undertook a systematic review, meta-analysis and meta-regression of diagnostic cohort studies that compared US to contrast venography in patients with suspected DVT. We searched Medline, EMBASE, CINAHL, Web of Science, Cochrane Database of Systematic Reviews, Cochrane Controlled Trials Register, Database of Reviews of Effectiveness, the ACP Journal Club, and citation lists (1966 to April 2004). Random effects meta-analysis was used to derive pooled estimates of sensitivity and specificity. Random effects meta-regression was used to identify study-level covariates that predicted diagnostic performance. Results We identified 100 cohorts comparing US to venography in patients with suspected DVT. Overall sensitivity for proximal DVT (95% confidence interval) was 94.2% (93.2 to 95.0), for distal DVT was 63.5% (59.8 to 67.0), and specificity was 93.8% (93.1 to 94.4). Duplex US had pooled sensitivity of 96.5% (95.1 to 97.6) for proximal DVT, 71.2% (64.6 to 77.2) for distal DVT and specificity of 94.0% (92.8 to 95.1). Triplex US had pooled sensitivity of 96.4% (94.4 to 97.1%) for proximal DVT, 75.2% (67.7 to 81.6) for distal DVT and specificity of 94.3% (92.5 to 95.8). Compression US alone had pooled sensitivity of 93.8 % (92.0 to 95.3%) for proximal DVT, 56.8% (49.0 to 66.4) for distal DVT and specificity of 97.8% (97.0 to 98.4). Sensitivity was higher in more recently published studies and in cohorts with higher prevalence of DVT and more proximal DVT, and was lower in cohorts that reported interpretation by a radiologist. Specificity was higher in cohorts that excluded patients with previous DVT. No studies were identified that compared repeat US to venography in all patients. Repeat US appears to have a positive yield of 1.3%, with 89% of these being confirmed by venography. Conclusion Combined colour-doppler US techniques have optimal sensitivity, while compression US has optimal specificity for DVT. However, all estimates are subject to substantial unexplained heterogeneity. The role of repeat scanning is very uncertain and based upon limited data
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