490 research outputs found

    Stability of exploratory multivariate data modeling in longitudinal data

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    Exploratory data-driven multivariate analysis provides a means of investigating underlying structure in complex data. To explore the stability of multivariate data modeling, we have applied a common method of multivariate modeling (factor analysis) to the Genetic Analysis Workshop 13 (GAW13) Framingham Heart Study data. Given the longitudinal nature of the data, multivariate models were generated independently for a number of different time points (corresponding to cross-sectional clinic visits for the two cohorts), and compared. In addition, each multivariate model was used to generate factor scores, which were then used as a quantitative trait in variance component-based linkage analysis to investigate the stability of linkage signals over time. We found surprisingly good correlation between factor models (i.e., predicted factor structures), maximum LOD scores, and locations of maximum LOD scores (0.81< ρ <0.94 for factor scores; ρ >0.99 for peak locations; and 0.67< ρ <0.93 for peak LOD scores). Furthermore, the regions implicated by linkage analysis with these factor scores have also been observed in other studies, further validating our exploratory modeling

    q-Analogue of Shock Soliton Solution

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    By using Jackson's q-exponential function we introduce the generating function, the recursive formulas and the second order q-differential equation for the q-Hermite polynomials. This allows us to solve the q-heat equation in terms of q-Kampe de Feriet polynomials with arbitrary N moving zeroes, and to find operator solution for the Initial Value Problem for the q-heat equation. By the q-analog of the Cole-Hopf transformation we construct the q-Burgers type nonlinear heat equation with quadratic dispersion and the cubic nonlinearity. In q -> 1 limit it reduces to the standard Burgers equation. Exact solutions for the q-Burgers equation in the form of moving poles, singular and regular q-shock soliton solutions are found.Comment: 13 pages, 5 figure

    Sociodemographic Correlates of Bariatric Surgery by Procedure Type among a Statewide Ethnically Diverse Patient Population

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    Florida Agency for Health Care Administration (AHCA) 2013 inpatient data was used to conduct a retrospective review using International Classification of Diseases 9th edition (ICD-9) procedure codes to examine the sociodemographic correlates of three bariatric procedures [Laparoscopic Roux-en-Y Gastric Bypass (RYGB), Laparoscopic Adjustable Gastric Banding (LAGB), and Sleeve Gastrectomy (SG)]. Race-ethnic groups included non-Hispanic white (NHW), non- Hispanic black (NHB), Hispanic, and other. The sample (n=6,424, mean age 46 years) was predominantly NHW (57.4%), female (74.9%), commercial-insurance carriers (51.2%), and severely obese (98.8%). SG was the most common procedure (57.9%) followed by RYGB (39.3%), and LAGB (2.8%). Regardless of bariatric procedure type, over 40% were covered by commercial insurance. The relationship between insurance status and bariatric procedure type was statistically significant (p\u3c0.01). However, race-ethnicity and bariatric procedure relationship was not significant after adjusting for age, sex, and insurance status. Despite the current high obesity frequencies across all demographics in the state of Florida, NHW women (compared to their sex-ethnic-specific counterparts) in our sample received the highest proportion of bariatric surgeries. Further research should examine why this finding continues despite obesity and its health-related consequences affecting all sex- ethnic groups

    Adaptive probability-based broadcast forwarding in energy-saving sensor networks

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    International audienceNetworking protocols for multihop wireless sensor networks (WSNs) are required to simultaneously minimize resource usage as well as optimize performance metrics such as latency and reliability. This article explores the energy-latency-reliability tradeoff for broadcast in WSNs by presenting a new protocol called PBBF. Essentially, for a given reliability level, energy and latency are found to be inversely related and our study quantifies this relationship at the reliability boundary. Therefore, PBBF offers an application designer considerable flexibility in the choice of desired operation points. Furthermore, we propose an extension to dynamically adjust the PBBF parameters to minimize the input required from the designer

    What Details are Needed for Wireless Simulations? - A Study of a Site-Specific Indoor Wireless Model

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    The wireless networking community continuously questions the accuracy and validity of simulation-based performance eval-uations. The main reason is the lack of widely-accepted models that represent the real wireless characteristics, especially at the physical (PHY) layer. Hence, the trend in wireless networking is to rely more and more on testbeds, which on one hand bring more realism to network and protocol evaluation, but on the other hand present a high implementation barrier before an idea is ready to be tested. Therefore, realistic network simulators are still very much needed to reduce the time and effort for “concept testing ” of novel ideas. In this case, the main question is how detailed should wireless simulators be to evaluate network and protocol performance. In this paper, we attempt a first answer to this question by using the Berlin Open Wireless Lab (BOWL) indoor model (BIM) in the ns-3 simulator. BIM includes several measurement-based models to characterize wireless com-munication such as frame detection ratio (FDR), frame error ratio (FER), capture and interference models. Through extensive measurements, we analyze the accuracy that we obtain with these PHY-layer models. Our experiments also show whether the detailed models at the PHY layer play an important role to represent transport layer performance in simulations. I

    Phytochemical and antioxidant characteristics of medlar fruits (Mespilus germanica L.)

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    Eleven medlar (Mespilus germanica L.) genotypes sampled from Turkey were analyzed for their fruit weight, fruit dimensions, fruit firmness, ostiole diameter, shape index, skin color, moisture (%), ash (%), reducing sugar (%), crude protein (%), pH, soluble solid content (%), vitamin C (mg/100 g), minerals (P, K, Ca, Mg, Fe, Zn, Mn), total phenolic content and total antioxidant capacity. A wide variation among genotypes on most of the searched parameters was evident. Fruit weight varied from 11.21 g to 33.24 g indicating high variability among genotypes. Determination of antioxidant activities by β-carotene–linoleic acid and 2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging assays resulted in average 80.8%, and 46.6 μg/ml FW DPPH, respectively. The total phenolic contents of eleven medlar genotypes varied from 114 to 293 mg gallic acid equivalent in 100 g fresh weight basis. The medlar fruits were found to be rich in terms of potassium, calcium, phosphorus, magnesium and iron

    Accuracy-preserving Measurement Collection for Realistic Wireless Simulations

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    Abstract—The wireless research community continuously ques-tions the accuracy and the validity of wireless simulation models. While this led to a shift to testbeds for experimental evaluation, wireless testbeds only provide evaluations in a well-defined set of scenarios. Furthermore, even for the deployment of limited sce-narios, testbeds require a complete system setup, which is a time-consuming and challenging process. Hence, realistic simulation models are needed to get early performance results before going through the tedious work involved with testbed experimentation. In our prior work, we proposed the Berlin Open Wireless Lab (BOWL) Indoor Model (BIM) [1] to improve the accuracy of physical (PHY) layer simulation models. In this paper, we propose an optimization to the BIM model (OptBIM), which reduces the measurement complexity to build the model. We validate both BIM and OptBIM at the PHY and transport layers. We see that OptBIM shows similar performance to BIM at the PHY and transport layers. Also, the total number of measurements necessary was reduced by at least 18%. The improvement comes from reducing the number of measurements by 8 times (e.g., from 144 to 18 in our study). I
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