1,643 research outputs found

    Interval Estimation For The Scale Parameter Of Burr Type X Distribution Based On Grouped Data

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    The application of some bootstrap type intervals for the scale parameter of the Burr type X distribution with grouped data is proposed. The general asymptotic confidence interval procedure (Chen & Mi, 2001) is studied. The performance of these intervals is investigated and compared. Some of the bootstrap intervals give better performance for situations of small sample size and heavy censoring

    Quartz-based flat-crystal resonant inelastic x-ray scattering spectrometer with sub-10 meV energy resolution

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    Continued improvement of the energy resolution of resonant inelastic x-ray scattering (RIXS) spectrometers is crucial for fulfilling the potential of this technique in the study of electron dynamics in materials of fundamental and technological importance. In particular, RIXS is the only alternative tool to inelastic neutron scattering capable of providing fully momentum resolved information on dynamic spin structures of magnetic materials, but is limited to systems whose magnetic excitation energy scales are comparable to the energy resolution. The state-of-the-art spherical diced crystal analyzer optics provides energy resolution as good as 25 meV but has already reached its theoretical limit. Here, we demonstrate a novel sub-10meV RIXS spectrometer based on flat-crystal optics at the Ir-L3_3 absorption edge (11.215∼\sim keV) that achieves an analyzer energy resolution of 3.9∼\simmeV, very close to the theoretical value of 3.7∼\simmeV. In addition, the new spectrometer allows efficient polarization analysis without loss of energy resolution. The performance of the instrument is demonstrated using longitudinal acoustical and optical phonons in diamond, and magnon in Sr3_3Ir2_2O7_7. The novel sub-10∼\simmeV RIXS spectrometer thus provides a window into magnetic materials with small energy scales

    Long Term Impact of New Jersey National Summer Transportation Institute Hosted at Rowan University on Career Choices of Cohorts (Evaluation)

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    In the summer of 2017, 2018, and 2019, the Center for Research in Education in Advanced Transportation Engineering Systems (CREATEs) at Rowan University hosted the National Safety Transportation Institute. The goal of this program is to provide an exposure to high school students to transportation engineering. More than 50% from underrepresented minority groups, including women, African American, and Hispanics/Latinos attended the twoweek program. In the summer of 2017 and 2019, the program was non-residential lasting four and two weeks, respectively. In summer 2018, the program was two-week residential. In all programs, the students got a chance to explore different modes of transportation, such air, road, rail, water, with an overarching theme of safety and sustainability. The experience was provided through: a) hands-on experiments; b) field trips; and c) federal, state and industry speakers. The goal of this paper is to evaluate how this program impacted their career choices. A total of 36 students have graduated from high school out of the total enrollment of 58 students. The authors reached out to all parents whose students completed the program and have graduated from high school. Of the 36 students, at least 20 indicated that they are pursuing a degree in engineering in college. Although the remaining 16 were unresponsive, it is most likely that the majority of high school graduates who participated in NSTI went on to pursue further engineering education. The authors will continue to reach out to the remaining students. The overwhelming response was one of appreciation at the opportunity provided their students to attend college-level engineering lectures, hands-on demonstrations and field trips to industry partners to which they would not otherwise have access. More specifically, many parents expressed confirmation that participating in the program opened their students’ minds to opportunities in engineering which they had not otherwise considered. In some cases, it was determined that participation simply confirmed the engineering field already chosen when the student entered the program. Another promising response was that several students expressed interest to return as speakers at future NSTI sessions. These NSTI graduates will be amazing role models for future participants of the NSTI program. The paper presents the findings about the career choice of the students and what aspects of the NSTI program, if any, impacted them the most. This paper will provide a blueprint to other NSTI programs across the country as they design their own curriculum

    Low-income minority mothers’ reports of infant health care utilisation compared with medical records

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    This study aimed to investigate mothers’ reporting of the nature, location, frequency and content of health care visits for their infants, as compared with data abstracted from the infants’ medical records. It was part of a community-based parenting intervention designed to improve preventive health care utilisation among minority mothers in Washington, DC. Mothers 18 years old with newborn infants and with poor or no prenatal care were enrolled in the study. A total of 160 mother–infant dyads completed the 12-month study. Mothers were interviewed when the infants were 4, 8 and 12 months old, and were asked to recall infant visits to all health care providers. Medical records from identified providers were used for verification. The number and type of immunisations given, types of providers visited, and reason for the visits were compared. Only about a quarter of mothers agreed with their infants’ medical records on the number of specific immunisations received. The mothers reported fewer polio (1.8 vs. 2.1, P = 0.006), diphtheria and tetanus toxoids and pertussis (DTP) (1.8 vs. 2.2, P = 0.002), and Haemophilus influenzae type b (HiB) (1.3 vs. 2.1, P \u3c 0.0001) immunisations than were recorded. Similarly, about a quarter of the mothers were unaware of any polio, DTP or hepatitis B immunisations given, as documented in the medical records, and 38% did not know that their infant was immunised for HiB. Nearly half of the mothers recalled more infant doctors’ visits than were recorded in the medical records (4.1 vs. 3.6 visits, P = 0.017). The mothers generally disagreed with the providers about the reason for a particular visit and reported fewer sick-baby visits (1.5 vs. 3.3, P \u3c 0.0001) than the providers recorded. Mothers’ reports and medical records matched in only 19% of the cases. In 47%, mothers under-reported and in 34% overreported the total number of visits. The strongest agreement between mothers’ reports and medical records was in the case of emergency room visits (63%). In conclusion, in this population, mothers’ reporting did not match that of providers with respect to specific information: the number of immunisations, the location where services were provided, and the classification of sick- vs. well-baby visits. Future studies that evaluate health care utilization data should take these discrepancies into consideration in their selection of information source, and in their interpretation of the data

    Prescriptive Analytics in Urban Policing Operations

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    Problem definition: We consider the case of prescriptive policing, that is, the data-driven assignment of police cars to different areas of a city. We analyze key problems with respect to prediction, optimization, and evaluation as well as trade-offs between different quality measures and crime types. Academic/practical relevance: Data-driven prescriptive analytics is gaining substantial attention in operations management research, and effective policing is at the core of the operations of almost every city in the world. Given the vast amounts of data increasingly collected within smart city initiatives and the growing safety challenges faced by urban centers worldwide, our work provides novel insights on the development and evaluation of prescriptive analytics applications in an urban context. Methodology: We conduct a computational study using crime and auxiliary data on the city of San Francisco. We analyze both strong and weak prediction methods along with two optimization formulations representing the deterrence and response time impact of police vehicle allocations. We analyze trade-offs between these effects and between different crime types. Results: We find that even weaker prediction methods can produce Pareto-efficient outcomes with respect to deterrence and response time. We identify three different archetypes of combinations of prediction methods and optimization objectives that constitute the Pareto frontier among the configurations we analyze. Furthermore, optimizing for multiple crime types biases allocations in a way that generally decreases single-type performance along one outcome metric but can improve it along the other. Managerial implications: Although optimization integrating all relevant crime types is theoretically possible, it is practically challenging because each crime type requires a collectively consistent weight. We present a framework combining prediction and optimization for a subset of key crime types with exploring the impact on the remaining types to support implementation of operations-focused smart city solutions in practice

    A Case of Device Lead Induced Severe Tricuspid Regurgitation and Right-Sided Heart Failure

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    Background: Interference of device leads with closure of the tricuspid leaflets can cause severe tricuspid regurgitation (TR) and right-sided heart failure, as can heart failure with reduced LV function (HfrEF), and left sided valve disease. Case Presentation: A 78-year-old male with history of coronary artery disease s/p remote coronary bypass, ischemic cardiomyopathy with left ventricular ejection fraction 35-40%, and inducible ventricular tachycardia status post defibrillator presented with worsening dyspnea on exertion, easy fatigue, lower extremity pitting edema, anasarca, abdominal bloating and new systolic murmurs at the right upper and left lower sternal borders. An Echocardiogram demonstrated severe aortic stenosis with secondary pulmonary hypertension, an RV systolic pressure of 50 mm Hg, severe bi-atrial enlargement, and severe TR in the region of his device lead. A transesophageal echo confirmed mechanical interference by the lead with closure of the septal leaflet. Symptoms initially improved with intravenous furosemide but were ultimately refractory to outpatient therapy with furosemide, and later transitioning to the longer acting torsemide. He was a poor candidate for surgical correction given prior bypass surgery with patent grafts. Transcatheter aortic valve implantation (TAVI) was performed in an effort to reduce pulmonary artery pressures, with concomitant guideline directed medical therapy (GDMT) for HFrEF, in hopes of reducing tricuspid regurgitation from RV pressure overload from left sided heart disease. A repeat echo demonstrated a reduced RV systolic pressure of 42 mm Hg, and improved TR to moderate to severe. Conclusions: While diuretics are the mainstay of therapy, medical therapies for management of severe TR are limited. Attention should be focused on the underlying etiology of the TR and classification as primary (abnormal valve leaflets--including device lead induced) or secondary (normal valve leaflets). This patient had mixed involvement and management was directed accordingly with TAVI and GDMT for HfrEF, with plans for the higher risk surgical TV repair or replacement should symptoms persist

    Entangled-Photon Imaging of a Pure Phase Object

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    We demonstrate experimentally and theoretically that a coherent image of a pure phase object may be obtained by use of a spatially incoherent illumination beam. This is accomplished by employing a two-beam source of entangled photons generated by spontaneous parametric down-conversion. Though each of the beams is, in and of itself, spatially incoherent, the pair of beams exhibits higher-order inter-beam coherence. One of the beams probes the phase object while the other is scanned. The image is recorded by measuring the photon coincidence rate using a photon-counting detector in each beam. Using a reflection configuration, we successfully imaged a phase object implemented by a MEMS micro-mirror array. The experimental results are in accord with theoretical predictions.Comment: 11 pages, 3 figures, submittedto Phys. Rev. Let
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