1,936 research outputs found

    Method of vibration isolating an aircraft engine

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    A method for coupling an engine to a support frame for mounting to a fuselage of an aircraft using a three point vibration isolating mounting system in which the load reactive forces at each mounting point are statically and dynamically determined. A first vibration isolating mount pivotably couples a first end of an elongated support beam to a stator portion of an engine with the pivoting action of the vibration mount being oriented such that it is pivotable about a line parallel to a center line of the engine. An aft end of the supporting frame is coupled to the engine through an additional pair of vibration isolating mounts with the mounts being oriented such that they are pivotable about a circumference of the engine. The aft mounts are symmetrically spaced to each side of the supporting frame by 45 degrees. The relative orientation between the front mount and the pair of rear mounts is such that only the rear mounts provide load reactive forces parallel to the engine center line, in support of the engine to the aircraft against thrust forces. The forward mount is oriented so as to provide only radial forces to the engine and some lifting forces to maintain the engine in position adjacent a fuselage. Since each mount is connected to provide specific forces to support the engine, forces required of each mount are statically and dynamically determinable

    Annual Report of the Extension Division for the Year Ending June 30, 1918

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    The past year has been one of unusual activity along the various phases of agricultural extension. South Dakota had a program of extension mapped out in accordance with the provisions of the South Dakota law enacted in 1915 and 1917, and also in accordance with the federal Smith-Lever Act passed by Congress in May, 1914. With the declaration of war, Congress and those officials in immediate responsibility realized the great importance of supplying our armies and allies with food. In order to speed up the food production program, Congress made an emergency appropriation. This enabled the States, Relations Service to finance men who are capable organizers and expert farmers and also home demonstrators, and boys\u27 .and girls\u27 club workers in counties of South Dakota not already organized under our state law. These men thus in charge of the food production work are known as emergency demonstration agents, the ladies, as home demonstration agents, and those in charge of the junior extension as boys\u27 and girls\u27 club leaders

    The Effects of a Commercial, Pre-exercise Energy Drink Supplement on Power, Muscular Endurance, and Repeated Sprint Speed

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    International Journal of Exercise Science 9(2): 205-213, 2016. The purpose of this study was to investigate the effects of ingesting a pre-workout commercial energy drink supplement on multiple parameters of physical performance, including upper body and trunk muscular endurance, muscular power, and repeated sprint speed. 19 college-aged males (n = 8) and females (n = 11) participated in this randomized, double-blind, parallel groups study. At baseline and post-testing (about one week after baseline testing), anaerobic power (assessed via a countermovement vertical jump), muscular endurance (assessed via YMCA bench press test and a curl-up test), and repeated sprint speed were assessed. Thirty minutes prior to post-testing, subjects ingested one serving (1.75 ounces [37 ml]) of a calorie-free, caffeine-containing pre-exercise energy supplement (Redline Power Rush by VPX) (n = 10) or an isovolumetric and similar tasting placebo beverage (n = 9). While vertical jump, YMCA bench press, and repeated sprint speed improved from pre to post testing in both treatment groups, there were no differences between the energy drink and placebo beverages. Curl-up endurance performance improved following the energy drink ingestion but did not improve following placebo ingestion. However, this observation also failed to reach statistical significance (p = 0.120). A possible explanation for the lack of effect of the pre-exercise energy drink to enhance physical performance was the relatively low amount of caffeine that was present in the beverage (providing an average of 2.4 mg caffeine/kg body mass)

    Effects of bolt torque tightening on the strength and fatigue life of airframe FRP laminate bolted joints

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    The experimental study presented herein, investigated the effects of bolt torque tightening on the strength and fatigue design of bolted AS7/8552 fibre reinforced polymer laminates. Damage initiation and final failure manifestation on the joints was investigated and presented using optical microscopy. Subsequent experimental result analysis explored the application domain of bolted joints within the airframe design sector, bound by the current airworthiness certification requirements and expected airframe design life. The reasons for the static strength of the joint laminates or the fatigue failure of the bolt being the main design drivers for the tested joints were highlighted. The study concluded with comments and suggestions on the application of bolt torque tightening in relation to the strength, fatigue life and damage tolerance characteristics of joints on similar fibre reinforced polymer laminate composite material systems

    Resonance bifurcations from robust homoclinic cycles

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    We present two calculations for a class of robust homoclinic cycles with symmetry Z_n x Z_2^n, for which the sufficient conditions for asymptotic stability given by Krupa and Melbourne are not optimal. Firstly, we compute optimal conditions for asymptotic stability using transition matrix techniques which make explicit use of the geometry of the group action. Secondly, through an explicit computation of the global parts of the Poincare map near the cycle we show that, generically, the resonance bifurcations from the cycles are supercritical: a unique branch of asymptotically stable period orbits emerges from the resonance bifurcation and exists for coefficient values where the cycle has lost stability. This calculation is the first to explicitly compute the criticality of a resonance bifurcation, and answers a conjecture of Field and Swift in a particular limiting case. Moreover, we are able to obtain an asymptotically-correct analytic expression for the period of the bifurcating orbit, with no adjustable parameters, which has not proved possible previously. We show that the asymptotic analysis compares very favourably with numerical results.Comment: 24 pages, 3 figures, submitted to Nonlinearit

    The Effects of a Pre-Workout Energy Drink on Measures of Physical Performance

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    The purpose of this study was to investigate the effects of a pre-workout commercial energy drink on parameters of exercise performance, including anaerobic power, muscular endurance, speed, and reaction time. This study used a randomized, double blind, placebo controlled, parallel design. Participants visited the laboratory on two different occasions. On the first visit, participants were assessed for anaerobic power (via a vertical jump test), muscular endurance, reaction time, reactive sprint test, and aerobic power (via a 1.5 mile run). On the second visit, participants were randomly assigned to ingest four ounces of the energy drink beverage or a similar-tasting placebo beverage 30-minutes prior to engaging in these same physical performance tests. The energy drink treatment had no effect on anaerobic power (vertical jump), reaction time, reactive sprint test, or aerobic power. For the push-up to fatigue test, a significant difference (p = 0.014) was observed with the energy drink treatment enhancing performance by 12% as compared to the placebo treatment (improvement of ~ 4%). For the sit-up to fatigue test, a non-significant difference (p = 0.075) was observed with the energy drink treatment resulting in an enhancement of performance by ~13% as compared to no improvement for the placebo treatment. In light of these findings, individuals whose upper-body muscular endurance performance is part of their physical fitness assessment program may benefit from pre-workout energy drink consumption. In contrast, individuals needing to demonstrate anaerobic/aerobic power, or reactive abilities should not expect an improvement in performance from pre-workout energy drink consumption

    The MH1 domain of Smad3 interacts with Pax6 and represses autoregulation of the Pax6 P1 promoter

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    Pax6 transcription is under the control of two main promoters (P0 and P1), and these are autoregulated by Pax6. Additionally, Pax6 expression is under the control of the TGFβ superfamily, although the precise mechanisms of such regulation are not understood. The effect of TGFβ on Pax6 expression was studied in the FHL124 lens epithelial cell line and was found to cause up to a 50% reduction in Pax6 mRNA levels within 24 h. Analysis of luciferase reporters showed that Pax6 autoregulation of the P1 promoter, and its induction of a synthetic promoter encoding six paired domain-binding sites, were significantly repressed by both an activated TGFβ receptor and TGFβ ligand stimulation. Subsequently, a novel Pax6 binding site in P1 was shown to be necessary for autoregulation, indicating a direct influence of Pax6 protein on P1. In transfected cells, and endogenously in FHL124 cells, Pax6 co-immunoprecipitated with Smad3 following TGFβ receptor activation, while in GST pull-down experiments, the MH1 domain of Smad3 was observed binding the RED sub-domain of the Pax6 paired domain. Finally, in DNA adsorption assays, activated Smad3 inhibited Pax6 from binding the consensus paired domain recognition sequence. We hypothesize that the Pax6 autoregulatory loop is targeted for repression by the TGFβ/Smad pathway, and conclude that this involves diminished paired domain DNA-binding function resulting from a ligand-dependant interaction between Pax6 and Smad3

    Voting and the Cardinal Aggregation of Judgments

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    The paper elaborates the idea that voting is an instance of the aggregation of judgments, this being a more general concept than the aggregation of preferences. To aggregate judgments one must first measure them. I show that such aggregation has been unproblematic whenever it has been based on an independent and unrestricted scale. The scales analyzed in voting theory are either context dependent or subject to unreasonable restrictions. This is the real source of the diverse 'paradoxes of voting' that would better be termed 'voting pathologies'. The theory leads me to advocate what I term evaluative voting. It can also be called utilitarian voting as it is based on having voters express their cardinal preferences. The alternative that maximizes the sum wins. This proposal operationalizes, in an election context, the abstract cardinal theories of collective choice due to Fleming and Harsanyi. On pragmatic grounds, I argue for a three valued scale for general elections

    The implementation of pharmacogenomics into UK general practice: a qualitative study exploring barriers, challenges and opportunities

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    Funder: St. George's University of LondonAbstract: Pharmacogenomics describes interpatient genetic variability in drug responses. Information based on whole genome sequencing will soon open up the field of pharmacogenomics and facilitate the use of genomic information relating to drug metabolism and drug responses. We undertook a qualitative study, aiming to explore the potential barriers, opportunities and challenges facing the implementation of pharmacogenomics into primary care. Semi-structured interviews were undertaken with 18 clinical participants (16 GPs and 2 other clinicians). All interviews were recorded and transcribed verbatim. Using a thematic analysis approach, data items were coded, ordered and themes constructed. Most participants were aged 55–60 years and worked as part-time clinical GPs with other clearly defined roles. The emerging themes covered several areas of concern, including the following: the utility of pharmacogenomics and the value of introducing such testing into primary care; how to educate the primary care workforce and ‘mainstream’ pharmacogenomics; the ethical, legal and social aspects of pharmacogenomics and its impact on patients; and potential impacts on the healthcare system particularly around economics and informatics. Most participants had concerns about pharmacogenomics and felt that there were a number of barriers and challenges to its implementation into routine primary care. Most striking were their concerns around the cost-effectiveness of using pharmacogenomics in primary care. At the same time most recognised the increasing availability of direct-to-consumer testing, and felt that this would drive the need to understand the ethical and social implications of using genomic information in primary care. This study has raised important issues that need to be considered when planning the implementation of pharmacogenomics into clinical practice. Prior to the implementation of genomic testing into day-to-day practice in UK primary care, it is important that considerations around education, cost-effectiveness and informatics are addressed, as well as the impact on patients

    Stability of narrow beams in bulk Kerr-type nonlinear media

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    We consider (2+1)-dimensional beams, whose transverse size may be comparable to or smaller than the carrier wavelength, on the basis of an extended version of the nonlinear Schr\"{o}dinger equation derived from the Maxwell`s equations. As this equation is very cumbersome, we also study, in parallel to it, its simplified version which keeps the most essential term: the term which accounts for the {\it nonlinear diffraction}. The full equation additionally includes terms generated by a deviation from the paraxial approximation and by a longitudinal electric-field component in the beam. Solitary-wave stationary solutions to both the full and simplified equations are found, treating the terms which modify the nonlinear Schr\"{o}dinger equation as perturbations. Within the framework of the perturbative approach, a conserved power of the beam is obtained in an explicit form. It is found that the nonlinear diffraction affects stationary beams much stronger than nonparaxiality and longitudinal field. Stability of the beams is directly tested by simulating the simplified equation, with initial configurations taken as predicted by the perturbation theory. The numerically generated solitary beams are always stable and never start to collapse, although they display periodic internal vibrations, whose amplitude decreases with the increase of the beam power.Comment: 7 pages, 6 figures Accepted for publication in PR
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