1,264 research outputs found

    Wind Tunnel Results of the B-52B with the X-43A Stack

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    A low-speed wind-tunnel test was performed with a three-percent-scale model of a booster rocket mated to an X-43A research vehicle, a combination referred to as the Hyper-X launch vehicle. The test was conducted both in free-stream air and in the presence of a partial model of the B-52B airplane. The objectives of the test were to obtain force and moment data to generate structural loads affecting the pylon of the B-52B airplane and to determine the aerodynamic influence of the B-52B airplane on the Hyper-X launch vehicle to evaluate launch separation characteristics. The wind-tunnel test was conducted at a low-speed wind tunnel in Hampton, Virginia. All moments and forces reported are based either on the aerodynamic influence of the B-52B airplane or are for the Hyper-X launch vehicle in free-stream air. Overall, the test showed that the B-52B airplane imparts a strong downwash onto the Hyper-X launch vehicle, reducing the net lift of the Hyper-X launch vehicle. Also, pitching and rolling moments are imparted onto the booster and are a strong function of the launch-drop angle of attack

    Wind-Tunnel Results of the B-52B with the X-43A Stack

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    A low-speed wind-tunnel test was performed with a 3%-scale model of a booster rocket mated to an X-43A research vehicle, a combination referred to as the Hyper-X launch vehicle. The test was conducted both in freestream air and in the presence of a partial model of the B-52B airplane. The objectives of the test were to obtain force and moment data to generate structural loads affecting the pylon of the B-52B airplane and to determine the aerodynamic influence of the B-52B on the Hyper-X launch vehicle for evaluating launch separation characteristics. The windtunnel test was conducted at a low-speed wind tunnel in Hampton, Virginia. All moments and forces reported are based either on the aerodynamic influence of the B-52B airplane or are for the Hyper-X launch vehicle in freestream air. Overall, the test showed that the B-52B airplane imparts a strong downwash onto the Hyper-X launch vehicle, reducing the net lift of the Hyper-X launch vehicle. Pitching and rolling moments are also imparted onto the booster and are a strong function of the launch-drop angle of attack

    Effect of Military Deployment on Diabetes Mellitus in Air Force Personnel

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    Introduction: Military deployments relocate service members to austere locations with limited medical capabilities, raising uncertainties whether members with diabetes can participate safely. Military regulations require a medical clearance for service members with diabetes prior to deployment, but there is a dearth of data that can guide the provider in this decision. To alleviate the lack of evidence in this area, we analyzed the change in glycated hemoglobin (HbA1c) and body mass index (BMI) before and after a deployment among active duty U.S. Air Force personnel who deployed with diabetes. Materials and Methods: A retrospective analysis was conducted using HbA1c and BMI values obtained within 3 mo before and within 3 mo after repatriation from a deployment of at least 90 d between January 1, 2004 through December 31, 2014. The study population consisted of 103 and 195 subjects who had an available pre- and post-deployment HbA1c and BMI values, respectively. Paired t-tests were conducted to determine significant differences in HbA1C and BMI values. Results: The majority (73.8%) of members had a HbA1c7%. BMI declined for the overall population (28.3 kg/m2 vs. 27.7 kg/m2, p \u3c 0.0001) and for most of the subgroups. Conclusion: Air Force service members who deployed with diabetes, including those with a HbA1c \u3e 7%, experienced a statistically significant improvement in HbA1c and BMI upon repatriation. A prospective study design in the future can better reconcile the effect of a military deployment on a more comprehensive array of diabetes parameters

    Fostering implementation of health services research findings into practice: a consolidated framework for advancing implementation science

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    Abstract Background Many interventions found to be effective in health services research studies fail to translate into meaningful patient care outcomes across multiple contexts. Health services researchers recognize the need to evaluate not only summative outcomes but also formative outcomes to assess the extent to which implementation is effective in a specific setting, prolongs sustainability, and promotes dissemination into other settings. Many implementation theories have been published to help promote effective implementation. However, they overlap considerably in the constructs included in individual theories, and a comparison of theories reveals that each is missing important constructs included in other theories. In addition, terminology and definitions are not consistent across theories. We describe the Consolidated Framework For Implementation Research (CFIR) that offers an overarching typology to promote implementation theory development and verification about what works where and why across multiple contexts. Methods We used a snowball sampling approach to identify published theories that were evaluated to identify constructs based on strength of conceptual or empirical support for influence on implementation, consistency in definitions, alignment with our own findings, and potential for measurement. We combined constructs across published theories that had different labels but were redundant or overlapping in definition, and we parsed apart constructs that conflated underlying concepts. Results The CFIR is composed of five major domains: intervention characteristics, outer setting, inner setting, characteristics of the individuals involved, and the process of implementation. Eight constructs were identified related to the intervention (e.g., evidence strength and quality), four constructs were identified related to outer setting (e.g., patient needs and resources), 12 constructs were identified related to inner setting (e.g., culture, leadership engagement), five constructs were identified related to individual characteristics, and eight constructs were identified related to process (e.g., plan, evaluate, and reflect). We present explicit definitions for each construct. Conclusion The CFIR provides a pragmatic structure for approaching complex, interacting, multi-level, and transient states of constructs in the real world by embracing, consolidating, and unifying key constructs from published implementation theories. It can be used to guide formative evaluations and build the implementation knowledge base across multiple studies and settings.http://deepblue.lib.umich.edu/bitstream/2027.42/78272/1/1748-5908-4-50.xmlhttp://deepblue.lib.umich.edu/bitstream/2027.42/78272/2/1748-5908-4-50-S1.PDFhttp://deepblue.lib.umich.edu/bitstream/2027.42/78272/3/1748-5908-4-50-S3.PDFhttp://deepblue.lib.umich.edu/bitstream/2027.42/78272/4/1748-5908-4-50-S4.PDFhttp://deepblue.lib.umich.edu/bitstream/2027.42/78272/5/1748-5908-4-50.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/78272/6/1748-5908-4-50-S2.PDFPeer Reviewe

    Sarcopenia is associated with blood transfusions in head and neck cancer free flap surgery

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    Objective: To determine if sarcopenia is a predictor of blood transfusion requirements in head and neck cancer free flap reconstruction (HNCFFR). Methods: A single-institution, retrospective review was performed of HNCFFR patients with preoperative abdominal imaging from 2014 to 2019. Demographics, comorbidities (modified Charlson Comorbidity Index [mCCI]), skeletal muscle index (cm2/m2), oncologic history, intraoperative data, and 30-day postoperative complications (Clavien-Dindo score [CD]) were collected. Binary logistic regression was performed to determine predictors of transfusion. Results: Eighty (33.5%), 66 (27.6%), and 110 (46.0%) of n = 239 total patients received an intraoperative, postoperative, or any perioperative blood transfusion, respectively. Sixty-two (25.9%) patients had sarcopenia. Patients receiving intraoperative transfusions had older age (P = .035), more frequent alcoholism (P = .028) and sarcopenia (P < .001), greater mCCI (P < .001), lower preoperative hemoglobin (P < .001), reconstruction with flaps other than forearm (P = .003), and greater operative times (P = .001), intravenous fluids (P < .001), and estimated blood loss (EBL, P < .001). Postoperative transfusions were associated with major complications (CD ≥ 3; P < .001). Multivariate regression determined sarcopenia (P = .023), mCCI (P = .013), preoperative hemoglobin (P = .002), operative time (P = .036), and EBL (P < .001) as independent predictors of intraoperative transfusion requirements. Postoperative transfusions were predicted by preoperative hemoglobin (P = .007), osseous flap (P = .036), and CD ≥ 3 (P < .001). A perioperative transfusion was predicted by sarcopenia (P = .021), preoperative hemoglobin (P < .001), operative time (P = .008), and CD ≥ 3 (P = .018). Conclusion: Sarcopenia is associated with increased blood transfusions in HNCFFR. Patients should be counseled preoperatively on the associated risks, and the increased blood product requirement should be accounted in resource-limited scenarios

    Net Charge Fluctuations in Au + Au Interactions at sqrt(s_NN) = 130 GeV

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    Data from Au + Au interactions at sqrt(s_NN) = 130 GeV, obtained with the PHENIX detector at RHIC, are used to investigate local net charge fluctuations among particles produced near mid-rapidity. According to recent suggestions, such fluctuations may carry information from the Quark Gluon Plasma. This analysis shows that the fluctuations are dominated by a stochastic distribution of particles, but are also sensitive to other effects, like global charge conservation and resonance decays.Comment: 6 pages, RevTeX 3, 3 figures, 307 authors, submitted to Phys. Rev. Lett. on 21 March, 2002. Plain text data tables for the points plotted in figures for this and previous PHENIX publications are (will be made) publicly available at http://www.phenix.bnl.gov/phenix/WWW/run/phenix/papers.htm

    Scaling properties of proton and anti-proton production in sqrt(s_NN) = 200 GeV Au + Au collisions

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    We report on the yield of protons and anti-protons, as a function of centrality and transverse momentum, in Au+Au collisions at sqrt(s_NN) = 200 GeV measured at mid-rapidity by the PHENIX experiment at RHIC. In central collisions at intermediate transverse momenta (1.5 < p_T < 4.5 GeV/c) a significant fraction of all produced particles are protons and anti-protons. They show a centrality-scaling behavior different from that of pions. The p-bar/pion and p/pion ratios are enhanced compared to peripheral Au+Au, p+p, and electron+positron collisions. This enhancement is limited to p_T < 5 GeV/c as deduced from the ratio of charged hadrons to pi^0 measured in the range 1.5 < p_T < 9 GeV/c.Comment: 325 authors, 6 pages text, 4 figures, RevTeX 4. Minor changes to text and figures to meet PRL length restrictions; no changes to figures; resubmitted to PRL. Plain text data tables for the points plotted in figures for this and previous PHENIX publications are (or will be) publicly available at http://www.phenix.bnl.gov/papers.htm

    Measurement of the mid-rapidity transverse energy distribution from sNN=130\sqrt{s_{NN}}=130 GeV Au+Au collisions at RHIC

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    The first measurement of energy produced transverse to the beam direction at RHIC is presented. The mid-rapidity transverse energy density per participating nucleon rises steadily with the number of participants, closely paralleling the rise in charged-particle density, such that E_T / N_ch remains relatively constant as a function of centrality. The energy density calculated via Bjorken's prescription for the 2% most central Au+Au collisions at sqrt(s_NN)=130 GeV is at least epsilon_Bj = 4.6 GeV/fm^3 which is a factor of 1.6 larger than found at sqrt(s_NN)=17.2 GeV (Pb+Pb at CERN).Comment: 307 authors, 6 pages, 4 figures, 1 table, submitted to PRL 4/18/2001; revised version submitted to PRL 5/24/200

    Event-by-event fluctuations in Mean pTp_T and Mean eTe_T in sqrt(s_NN) = 130 GeV Au+Au Collisions

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    Distributions of event-by-event fluctuations of the mean transverse momentum and mean transverse energy near mid-rapidity have been measured in Au+Au collisions at sqrt(s_NN) = 130 GeV at RHIC. By comparing the distributions to what is expected for statistically independent particle emission, the magnitude of non-statistical fluctuations in mean transverse momentum is determined to be consistent with zero. Also, no significant non-random fluctuations in mean transverse energy are observed. By constructing a fluctuation model with two event classes that preserve the mean and variance of the semi-inclusive p_T or e_T spectra, we exclude a region of fluctuations in sqrt(s_NN) = 130 GeV Au+Au collisions.Comment: 10 pages, RevTeX 3, 7 figures, 4 tables, 307 authors, submitted to Phys. Rev. C on 22 March 2002. Plain text data tables for the points plotted in figures for this and previous PHENIX publications are (will be made) publicly available at http://www.phenix.bnl.gov/phenix/WWW/run/phenix/papers.htm
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