2,611 research outputs found

    Patterns of Voting on Ballot Propositions: A Mixture Model of Voter Types

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    In this paper we analyze the patterns of behavior voters exhibit over a set of votes. We explore a set of structural estimation problems that involve analyzing several votes at one time and develop estimation techniques for identifying and analyzing patterns. Using the information in these patterns, we introduce a method for studying voter heterogeneity based on a finite mixture model. Finally, we employ data containing actual micro-level vote returns to estimate the mixture model parameters

    NRL tethered balloon measurements at San Nicolas Island during FIRE IFO 1987

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    An overview is given of the tethered balloon measurements made during the First ISCCP Regional Experiment (FIRE) marine stratocumulus intensive field observations (IFO) at San Nicolas Island in 1987. The instrument utilized on the balloon flights, the 17 flights over a 10 day period, the state of the data analysis, and some preliminary results are described. A goal of the measurements with the Naval Research Laboratory (NRL) balloon was to give a unique and greatly improved look at the microphysics of the clear and cloud-topped boundary layer. For this goal, collocated measurements were made of turbulence, aerosol, cloud particles, and meteorology. Two new instruments which were expected to make significant contributions to this effort were the saturation hygrometer, capable of measuring 95 percent less than RH 105 percent (with an accuracy of 0.05 percent near 100 percent) and used for the first time in clouds; and the forward scatter meter which gives in situ LWC measurements at more than 10 Hz. The data set, while unfortunately only partially simultaneous with the bulk of the FIRE stratocumulus observations, is unique and worthwhile in its own right. For the first time accurate RH measurements near 100 percent have been made in-cloud; although, the use of the saturation hygrometer reflected a learning experience which will result is substantially better performance the next time. These measurements were made in conjunction with other microphysical measurements such as aerosol and cloud droplet spectra, and perhaps most important of all, they were all collocated with bivane turbulence measurements thus permitting flux calculations. Thus the analysis of this data set, which consisted of about 50 percent stratocumulus cases including increasing and decreasing partial cloud cover, should lead to new insights on the physical mechanisms which drive the boundary-layer/cloud/turbulence system

    Development and application of an antibiotic spectrum index for benchmarking antibiotic selection patterns across hospitals

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    Standard metrics for antimicrobial use consider volume but not spectrum of antimicrobial prescribing. We developed an antibiotic spectrum index (ASI) to classify commonly used antibiotics based on activity against important pathogens. The application of this index to hospital antibiotic use reveals how this tool enhances current antimicrobial stewardship metrics.Infect Control Hosp Epidemiol 2017;38:993–997</jats:p

    Variability in antifungal and antiviral use in hospitalized children

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    We analyzed antifungal and antiviral prescribing among high-risk children across freestanding children’s hospitals. Antifungal and antiviral days of therapy varied across hospitals. Benchmarking antifungal and antiviral use and developing antimicrobial stewardship strategies to optimize use of these high cost agents is needed.Infect Control Hosp Epidemiol2017;38:743–746</jats:p

    Current state of antimicrobial stewardship in children’s hospital emergency departments

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    BACKGROUND Antimicrobial stewardship programs (ASPs) effectively optimize antibiotic use for inpatients; however, the extent of emergency department (ED) involvement in ASPs has not been described. OBJECTIVE To determine current ED involvement in children's hospital ASPs and to assess beliefs and preferred methods of implementation for ED-based ASPs. METHODS A cross-sectional survey of 37 children's hospitals participating in the Sharing Antimicrobial Resistance Practices collaboration was conducted. Surveys were distributed to ASP leaders and ED medical directors at each institution. Items assessed included beliefs regarding ED antibiotic prescribing, ED prescribing resources, ASP methods used in the ED such as clinical decision support and clinical care guidelines, ED participation in ASP activities, and preferred methods for ED-based ASP implementation. RESULTS A total of 36 ASP leaders (97.3%) and 32 ED directors (86.5%) responded; the overall response rate was 91.9%. Most ASP leaders (97.8%) and ED directors (93.7%) agreed that creation of ED-based ASPs was necessary. ED resources for antibiotic prescribing were obtained via the Internet or electronic health records (EHRs) for 29 hospitals (81.3%). The main ASP activities for the ED included production of antibiograms (77.8%) and creation of clinical care guidelines for pneumonia (83.3%). The ED was represented on 3 hospital ASP committees (8.3%). No hospital ASPs actively monitored outpatient ED prescribing. Most ASP leaders (77.8%) and ED directors (81.3%) preferred implementation of ED-based ASPs using clinical decision support integrated into the EHR. CONCLUSIONS Although ED involvement in ASPs is limited, both ASP and ED leaders believe that ED-based ASPs are necessary. Many children's hospitals have the capability to implement ED-based ASPs via the preferred method: EHR clinical decision support. Infect Control Hosp Epidemiol 2017;38:469-475

    VEGF-A has a critical, nonredundant role in angiogenic switching and pancreatic β cell carcinogenesis

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    AbstractIn the RIP1-Tag2 mouse model of pancreatic islet carcinoma, angiogenesis is switched on in a discrete premalignant stage of tumor development, persisting thereafter. Signaling through VEGF receptor tyrosine kinases is a well-established component of angiogenic regulation. We show that five VEGF ligand genes are expressed in normal islets and throughout islet tumorigenesis. To begin dissecting their contributions, we produced an islet β cell specific knockout of VEGF-A, resulting in islets with reduced vascularity but largely normal physiology. In RIP1-Tag2 mice wherein most oncogene-expressing cells had deleted the VEGF-A gene, both angiogenic switching and tumor growth were severely disrupted, as was the neovasculature. Thus, VEGF-A is crucial for angiogenesis in a prototypical model of carcinogenesis, whose loss is not readily compensated

    Patterns of Voting on Ballot Propositions: A Mixture Model of Voter Types

    Get PDF
    In this paper we analyze the patterns of behavior voters exhibit over a set of votes. We explore a set of structural estimation problems that involve analyzing several votes at one time and develop estimation techniques for identifying and analyzing patterns. Using the information in these patterns, we introduce a method for studying voter heterogeneity based on a finite mixture model. Finally, we employ data containing actual micro-level vote returns to estimate the mixture model parameters

    Compositional Verification by Model Checking for Counter-Examples

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    Many concurrent systems are required to maintain certain safety and liveness properties. One emerging method of achieving confidence in such systems is to statically verify them using "model checking". In this approach an abstract, finite-state model of the system is constructed; then an automatic check is made to ensure that the requirements are satisfied by the model. In practice, however, this method is limited by the "state space explosion problem". We have developed a compositional method that directly addresses this problem in the context of multi-tasking programs. Our solution depends on three key space-saving ingredients: (1) checking for counter-examples, which leads to simpler search algorithms; (2) automatic extraction of interfaces, which allows a refinement of the finite model -- even before its communicating partners have been compiled; and (3) using propositional "strengthening assertions" for the sole purpose of reducing state space. In this paper we present our compositional approach, and describe the software tools that support it. (Also cross-referenced as UMIACS-TR-95-98
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