1,067 research outputs found

    Laser pulse analysis

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    Methods are presented for locating threshold points by using laser pulse analysis. It was found that there are errors involved in the determination of each of these quantities, and an attempt was made to separate their effects on the overall range correction. Several series of corrected range measurements for fixed reflectors and satellites were obtained. Residuals were computed by fitting the range measurements to either fixed-reflector distances or short arcs of satellite orbits. Root mean square values of these residuals are presented

    Application of inertial instruments for DSN antenna pointing and tracking

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    The feasibility of using inertial instruments to determine the pointing attitude of the NASA Deep Space Network antennas is examined. The objective is to obtain 1 mdeg pointing knowledge in both blind pointing and tracking modes to facilitate operation of the Deep Space Network 70 m antennas at 32 GHz. A measurement system employing accelerometers, an inclinometer, and optical gyroscopes is proposed. The initial pointing attitude is established by determining the direction of the local gravity vector using the accelerometers and the inclinometer, and the Earth's spin axis using the gyroscopes. Pointing during long-term tracking is maintained by integrating the gyroscope rates and augmenting these measurements with knowledge of the local gravity vector. A minimum-variance estimator is used to combine measurements to obtain the antenna pointing attitude. A key feature of the algorithm is its ability to recalibrate accelerometer parameters during operation. A survey of available inertial instrument technologies is also given

    Corrections for Racial Disparities in Law Enforcement

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    Much empirical analysis has documented racial disparities at the beginning and end stages of criminal cases. However, our understanding about the perpetuation of—and even corrections for—differential outcomes in the process remains less than complete. This Article provides a comprehensive examination of criminal dispositions using all DWI cases in North Carolina from 2001 to 2011, focusing on several major decision points in the process. Starting with pretrial hearings and culminating in sentencing results, we track differences in outcomes by race and gender. Before sentencing, significant gaps emerge in the severity of pretrial release conditions that disadvantage black and Hispanic defendants. Yet when prosecutors decide whether to pursue charges, we observe an initial correction mechanism: Hispanic men are almost two-thirds more likely to have those charges dropped relative to white men. Although few cases survive after the plea bargaining stage, a second correction mechanism arises: Hispanic men are substantially less likely to receive harsher sentences and are sent to jail for significantly less time relative to white men. The first mechanism is based, in part, on prosecutors’ reviewing the strength of the evidence, but much more on declining to invest scarce resources in the pursuit of defendants who fail to appear for trial. The second mechanism seems to follow more directly from judicial discretion to reverse decisions made by law enforcement or prosecutors. We discuss possible explanations for these novel empirical results and review methods for more precisely identifying causal mechanisms in criminal justice

    Flexible structure control laboratory development and technology demonstration

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    An experimental structure is described which was constructed to demonstrate and validate recent emerging technologies in the active control and identification of large flexible space structures. The configuration consists of a large, 20 foot diameter antenna-like flexible structure in the horizontal plane with a gimballed central hub, a flexible feed-boom assembly hanging from the hub, and 12 flexible ribs radiating outward. Fourteen electrodynamic force actuators mounted to the hub and to the individual ribs provide the means to excite the structure and exert control forces. Thirty permanently mounted sensors, including optical encoders and analog induction devices provide measurements of structural response at widely distributed points. An experimental remote optical sensor provides sixteen additional sensing channels. A computer samples the sensors, computes the control updates and sends commands to the actuators in real time, while simultaneously displaying selected outputs on a graphics terminal and saving them in memory. Several control experiments were conducted thus far and are documented. These include implementation of distributed parameter system control, model reference adaptive control, and static shape control. These experiments have demonstrated the successful implementation of state-of-the-art control approaches using actual hardware

    Accuracy of elastic fusion biopsy in daily practice: results of a multicenter study of 2115 patients

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    OBJECTIVES: To assess the accuracy of Koelis fusion biopsy for the detection of prostate cancer and clinically significant prostate cancer in the everyday practice. METHODS: We retrospectively enrolled 2115 patients from 15 institutions in four European countries undergoing transrectal Koelis fusion biopsy from 2010 to 2017. A variable number of target (usually 2-4) and random cores (usually 10-14) were carried out, depending on the clinical case and institution habits. The overall and clinically significant prostate cancer detection rates were assessed, evaluating the diagnostic role of additional random biopsies. The cancer detection rate was correlated to multiparametric magnetic resonance imaging features and clinical variables. RESULTS: The mean number of targeted and random cores taken were 3.9 (standard deviation 2.1) and 10.5 (standard deviation 5.0), respectively. The cancer detection rate of Koelis biopsies was 58% for all cancers and 43% for clinically significant prostate cancer. The performance of additional, random cores improved the cancer detection rate of 13% for all cancers (P < 0.001) and 9% for clinically significant prostate cancer (P < 0.001). Prostate cancer was detected in 31%, 66% and 89% of patients with lesions scored as Prostate Imaging Reporting and Data System 3, 4 and 5, respectively. Clinical stage and Prostate Imaging Reporting and Data System score were predictors of prostate cancer detection in multivariate analyses. Prostate-specific antigen was associated with prostate cancer detection only for clinically significant prostate cancer. CONCLUSIONS: Koelis fusion biopsy offers a good cancer detection rate, which is increased in patients with a high Prostate Imaging Reporting and Data System score and clinical stage. The performance of additional, random cores seems unavoidable for correct sampling. In our experience, the Prostate Imaging Reporting and Data System score and clinical stage are predictors of prostate cancer and clinically significant prostate cancer detection; prostate-specific antigen is associated only with clinically significant prostate cancer detection, and a higher number of biopsy cores are not associated with a higher cancer detection rate

    From Warriors to Wingtips: The Leadership Transition of Retired Officers into the Public Sector

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    For personal and financial reasons some retired military officers seek second careers in the public sector. In entering local government, they are leaving a unique organization, and encountering a very different organizational culture. This study used grounded theory methodology to identify the key military leadership strategies and behaviors learned by military officers and to examine their applicability to local government. It focused on eleven retired naval and marine officers who served twenty or more years, attained a rank of lieutenant commander or major and above, and had worked in local San Diego government at the mid-management or executive level less than six years. Findings were triangulated with literature and other research. Participant data described rapid leadership development as a military priority shaped by early responsibility, education, mentoring and command experiences. Leadership practices include using a contingency leadership style, firm discipline, a controlled environment, straightforward communications, training and development, values, camaraderie building, a command presence, standard operating procedures and centrally-mandated change. Retired officers needed to adjust some military leadership practices to respond to the organizational systems and culture of local government. In addition, each encountered stereotypes of retired military officers that affected their image and capacity to influence their organization. The retired officers interviewed identified strategies that aided them in succeeding in the public sector. These included: using a coaching style to lead staff, following up on directives, actively managing performance, adopting a less direct communications style, improving employee selection and development, creating ownership, actively working to change systems, building influence and political relationships, introducing change by influence, consciously developing their reputation and countering stereotypes of military officers. Some retired officers used strategies that were less successful. These included: using a direct communication style, using military jargon, assuming compliance, accepting and criticizing the status quo, developing an inner circle, expecting the executive to initiate career development and direct change, becoming frustrated, and failing to react to stereotypes

    Multivalued SK-contractions with respect to b-generalized pseudodistances

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    A new class of multivalued non-self-mappings, called SK-contractions with respect to b-generalized pseudodistances, is introduced and used to investigate the existence of best proximity points by using an appropriate geometric property. Some new fixed point results in b-metric spaces are also obtained. Examples are given to support the usability of our main result

    1952: Abilene Christian College Bible Lectures - Full Text

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    Delivered in the Auditorium of Abilene Christian College, February, 1952 ABILENE, TEXAS PRICE, $3.00 firm foundation publishing house Box 77 Austin Cl, Texa

    DGIdb 2.0: Mining clinically relevant drug-gene interactions

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    The Drug–Gene Interaction Database (DGIdb, www. dgidb.org) is a web resource that consolidates dis-parate data sources describing drug–gene interac-tions and gene druggability. It provides an intuitive graphical user interface and a documented applica-tion programming interface (API) for querying these data. DGIdb was assembled through an extensive manual curation effort, reflecting the combined in-formation of twenty-seven sources. For DGIdb 2.0, substantial updates have been made to increase content and improve its usefulness as a resource for mining clinically actionable drug targets. Specif-ically, nine new sources of drug–gene interactions have been added, including seven resources specifi-cally focused on interactions linked to clinical trials. These additions have more than doubled the over-all count of drug–gene interactions. The total num-ber of druggable gene claims has also increased by 30%. Importantly, a majority of the unrestricted, publicly-accessible sources used in DGIdb are now automatically updated on a weekly basis, providing the most current information for these sources. Fi-nally, a new web view and API have been developed to allow searching for interactions by drug identifiers to complement existing gene-based search function-ality. With these updates, DGIdb represents a com-prehensive and user friendly tool for mining the druggable genome for precision medicine hypothe-sis generation
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