67 research outputs found

    Forecasting Fuels Support Equipment Requisitions

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    Within the past two years the Air Force has begun transitioning management of equipment from regionalized management at Command Equipment Management Offices (CEMOs) to centralized enterprise management offices. The fuels support equipment (FSE) inventory is a subcategory of Air Force equipment, the management of which has recently transferred from CEMOs to the Air Force Petroleum Agency (AFPA). Because FSE inventory was previously managed regionally, there is a gap in descriptive data for the enterprise FSE inventory. This study attempts to close this information gap through describing the current inventory position, defining historical FSE demand, and using this knowledge to forecast 2015\u27s anticipated FSE demand using time and unit aggregation in conjunction with simple exponential smoothing. The results are useful to AFPA as the enterprise manager of FSE and to Air Force Item Managers as the acquisition managers for FSE. Lastly, this research is intended as a stepping stone into more detail study of the AF FSE inventory and supply chain

    Assessment of Surgical Procedural Time, Pedicle Screw Accuracy, and Clinician Radiation Exposure of a Novel Robotic Navigation System Compared With Conventional Open and Percutaneous Freehand Techniques: A Cadaveric Investigation

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    STUDY DESIGN: Cadaveric study. OBJECTIVE: To evaluate accuracy, radiation exposure, and surgical time of a new robotic-assisted navigation (RAN) platform compared with freehand techniques in conventional open and percutaneous procedures. METHODS: Ten board-certified surgeons inserted 16 pedicle screws at T10-L5 (n = 40 per technique) in 10 human cadaveric torsos. Pedicle screws were inserted with (1) conventional MIS technique (L2-L5, patient left pedicles), (2) MIS RAN (L2-L5, patient right pedicles), (3) conventional open technique (T10-L1, patient left pedicles), and (4) open RAN (T10-L1, patient right pedicles). Output included (1) operative time, (2) number of fluoroscopic images, and (3) screw accuracy. RESULTS: In the MIS group, compared with the freehand technique, RAN allowed for use of larger screws (diameter: 6.6 ± 0.6 mm vs 6.3 ± 0.5 mm; length: 50.3 ± 4.1 mm vs 46.9 ± 3.5 mm), decreased the number of breaches \u3e2 mm (0 vs 7), fewer fluoroscopic images (0 ± 0 vs 108.3 ± 30.9), and surgical procedure time per screw (3.6 ± 0.4 minutes vs 7.6 ± 2.0 minutes) (all CONCLUSION: RAN significantly improved accuracy and decreased radiation exposure in comparison to freehand techniques in both conventional open and percutaneous surgical procedures in cadavers. RAN significantly increased setup time compared with both conventional procedures

    Prediction of cardiovascular outcomes with machine learning techniques: application to the Cardiovascular Outcomes in Renal Atherosclerotic Lesions (CORAL) study.

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    Background: Data derived from the Cardiovascular Outcomes in Renal Atherosclerotic Lesions (CORAL) study were analyzed in an effort to employ machine learning methods to predict the composite endpoint described in the original study. Methods: We identified 573 CORAL subjects with complete baseline data and the presence or absence of a composite endpoint for the study. These data were subjected to several models including a generalized linear (logistic-linear) model, support vector machine, decision tree, feed-forward neural network, and random forest, in an effort to attempt to predict the composite endpoint. The subjects were arbitrarily divided into training and testing subsets according to an 80%:20% distribution with various seeds. Prediction models were optimized within the CARET package of R. Results: The best performance of the different machine learning techniques was that of the random forest method which yielded a receiver operator curve (ROC) area of 68.1%±4.2% (mean ± SD) on the testing subset with ten different seed values used to separate training and testing subsets. The four most important variables in the random forest method were SBP, serum creatinine, glycosylated hemoglobin, and DBP. Each of these variables was also important in at least some of the other methods. The treatment assignment group was not consistently an important determinant in any of the models. Conclusion: Prediction of a composite cardiovascular outcome was difficult in the CORAL population, even when employing machine learning methods. Assignment to either the stenting or best medical therapy group did not serve as an important predictor of composite outcome. Clinical Trial Registration: ClinicalTrials.gov, NCT00081731

    Concentration-Dependent Effects of a Dietary Ketone Ester on Components of Energy Balance in Mice

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    Exogenous ketones may provide therapeutic benefit in treatment of obesity. Administration of the ketone ester (KE) R,S-1,3-butanediol acetoacetate diester (BD-AcAc) decreases body weight in mice, but effects on energy balance have not been extensively characterized. The purpose of this investigation was to explore concentration-dependent effects of BD-AcAc on energy intake and expenditure in mice. Forty-two male C57BL/6J mice were randomly assigned to one of seven isocaloric diets ( = 6 per group): (1) Control (CON, 0% KE by kcals); (2) KE5 (5% KE); (3) KE10 (10% KE); (4) KE15 (15% KE); (5) KE20 (20% KE); (6) KE25 (25% KE); and (7) KE30 (30% KE) for 3 weeks. Energy intake and body weight were measured daily. Fat mass (FM), lean body mass (LBM), and energy expenditure (EE) were measured at completion of the study. Differences among groups were compared to CON using ANOVA and ANCOVA. Mean energy intake was similar between CON and each concentration of KE, except KE30 which was 12% lower than CON ( \u3c 0.01). KE25 and KE30 had lower body weight and FM compared to CON, while only KE30 had lower LBM ( \u3c 0.03). Adjusted resting and total EE were lower in KE30 compared to CON ( \u3c 0.03), but similar for all other groups. A diet comprised of 30% energy from BD-AcAc results in lower energy intake, coincident with lower body weight and whole animal adiposity; while KE20 and KE25 have significantly lower body weight and adiposity effects independent of changes in energy intake or expenditure

    Više-fragmentna tvorba u reakcijama 32S+58,64Ni NA 11 A MeV

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    The characteristic features of the 32S+58,64Ni reaction at 11 A MeV have been investigated to evidence the possible rise of multi-fragmentation processes at low excitation energies. The importance of such phenomena consists in the fact that they could represent the signature of a nuclear phase transition from a liquid to a gas region. Evidence of multi-fragment production is displayed by the present data; even if the yield of such events is compatible with the predictions of statistical models, the partition of the mass of the decaying system cannot be easily reproduced. Some preliminary indications of isospin effects are suggested by looking at the differences between the two reacting systems.Istraživali smo značajke reakcije 32S+ 58,64Ni na 11 A MeV radi pronalaženja mogućeg porasta više-fragmentnih procesa na nižim uzbudnim energijama. Važnost se tih pojava sastoji u tome što bi one mogle predstavljati znakove nuklearnog faznog prijelaza od tekućeg u plinsko stanje. Znakovi tvorbe više fragmenata vide se u dobivenim podacima; no čak ako je i prinos tih događaja u skladu s predviđanjima statističkog modela, razdioba mase sustava koji se raspada ne uspijeva se objasniti. Usporedba dviju reakcija ukazuje na moguće izospinske efekte

    Više-fragmentna tvorba u reakcijama 32S+58,64Ni NA 11 A MeV

    Get PDF
    The characteristic features of the 32S+58,64Ni reaction at 11 A MeV have been investigated to evidence the possible rise of multi-fragmentation processes at low excitation energies. The importance of such phenomena consists in the fact that they could represent the signature of a nuclear phase transition from a liquid to a gas region. Evidence of multi-fragment production is displayed by the present data; even if the yield of such events is compatible with the predictions of statistical models, the partition of the mass of the decaying system cannot be easily reproduced. Some preliminary indications of isospin effects are suggested by looking at the differences between the two reacting systems.Istraživali smo značajke reakcije 32S+ 58,64Ni na 11 A MeV radi pronalaženja mogućeg porasta više-fragmentnih procesa na nižim uzbudnim energijama. Važnost se tih pojava sastoji u tome što bi one mogle predstavljati znakove nuklearnog faznog prijelaza od tekućeg u plinsko stanje. Znakovi tvorbe više fragmenata vide se u dobivenim podacima; no čak ako je i prinos tih događaja u skladu s predviđanjima statističkog modela, razdioba mase sustava koji se raspada ne uspijeva se objasniti. Usporedba dviju reakcija ukazuje na moguće izospinske efekte
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