14,431 research outputs found

    Subsonic aerodynamic characteristics of a proposed advanced manned launch system orbiter configuration

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    The Advanced Manned Launch System is a proposed near-term technology, two-stage, fully reusable launch system that consists of an unmanned glide-back booster and a manned orbiter. An orbiter model that featured a large fuselage and an aft delta wing with tip fins was tested in the Langley 7- by 10-Foot High-Speed Tunnel. A crew cabin, large payload fairing, and crew access tunnel were mounted on the upper body. The results of the investigation indicated that the configuration was longitudinally stable to an angle of attack of about 6 deg about a center-of-gravity position of 0.7 body length. The model had an untrimmed lift-drag ratio of 6.6, but could not be trimmed at positive lift. The orbiter model was also directionally unstable. The payload fairing was responsible for about half the instability. The tip-fin controllers, which are designed as active controls to produce artificial directional stability, were effective in producing yawing moment, but sizable adverse rolling moment occurred at angles of attack above 6 deg. Differential deflection of the elevon surfaces was effective in producing rolling moment with only small values of adverse yawing moment

    Single Photon Source with Individualized Single Photon Certifications

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    As currently implemented, single-photon sources cannot be made to produce single photons with high probability, while simultaneously suppressing the probability of yielding two or more photons. Because of this, single photon sources cannot really produce single photons on demand. We describe a multiplexed system that allows the probabilities of producing one and more photons to be adjusted independently, enabling a much better approximation of a source of single photons on demand. The scheme uses a heralded photon source based on parametric downconversion, but by effectively breaking the trigger detector area into multiple regions, we are able to extract more information about a heralded photon than is possible with a conventional arrangement. This scheme allows photons to be produced along with a quantitative ``certification'' that they are single photons. Some of the single-photon certifications can be significantly better than what is possible with conventional downconversion sources (using a unified trigger detector region), as well as being better than faint laser sources. With such a source of more tightly certified single photons, it should be possible to improve the maximum secure bit rate possible over a quantum cryptographic link. We present an analysis of the relative merits of this method over the conventional arrangement.Comment: 11 pages, 5 figures, SPIE Free-Space Laser Communication and Laser Imaging II. To appear in the proceeding of SPIE Free-Space Laser Communication and Laser Imaging II, vol 482

    INVESTIGATION OF THE LOW-SUBSONIC STABILITY AND CONTROL CHARACTERISTICS OF A 0.34 -SCALE FREE-FLYING MODEL OF A MODIFIED HALF-CONE REENTRY VEHICLE

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    Low subsonic stability and control of a 0.34-scale free flying model of a half cone reentry vehicl

    Interactions between the endocrine and immune systems in locusts

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    The prophenoloxidase cascade in the haemolymph of mature adult Locusta migratoria migratorioides (R & F) is activated in response to injection of laminarin, a -1,3 glucan. Co-injection of adipokinetic hormone-I (Lom-AKH-I) and laminarin prolongs the activation of the enzyme in a dose-dependent manner. However, injections of bacterial lipopolysaccharide (LPS) do not activate prophenoloxidase unless AKH is co-injected, when there is a dose-dependent increase in the level of phenoloxidase that persists in the haemolymph for several hours. Even when AKH is co-injected, the highest levels of phenoloxidase activity are always greater after injection of laminarin than after LPS, and these two immunogens must activate the prophenoloxidase cascade by quite distinct pathways. In the present study, interactions between the endocrine and immune systems were examined with respect to activation of prophenoloxidase and the formation of nodules: injection of LPS induces nodule formation in adult locusts. With LPS from Pseudomonas aeruginosa, nodules form exclusively in dense accumulations in the anterior portion of the abdomen on either side of the dorsal blood vessel associated with the dorsal diaphragm. However, with LPS from Escherichia coli, fewer nodules are formed but with a similar distribution, except that occasionally some nodules are aligned additionally on either side of the ventral nerve cord. Co-injection of Lom-AKH-I with LPS from either bacteria stimulates greater numbers of nodules to be formed. This effect of coinjection of AKH on nodule formation is seen at low doses of hormone with only 0.3 or 0.4 pmol of Lom-AKH-1, respectively, increasing the number of nodules by 50%. Injections of octopamine or 5-hydroxytryptamine do not mimic either of the actions of Lom-AKH-I described here. Co-injection of an angiotensin-converting enzyme inhibitor, captopril, reduces nodule formation in response to injections of LPS but has no effect on the activation of phenoloxidase. Co-injection of an inhibitor of eicosanoid synthesis, dexamethasone, with LPS influences nodule formation (with or without AKH) in different ways according to the dose of dexamethasone used, but does not affect activation of prophenoloxidase. Eicosanoid synthesis is important for nodule formation, but not for the activation of the prophenoloxidase cascade in locust haemolymph

    Evaluation of Genetic Causes of Cardiomyopathy in Childhood

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    Cardiomyopathy frequently has a genetic basis. In adults, mutations in genes encoding components of the sarcomere, cytoskeleton, or desmosome are frequent genetic causes of cardiomyopathy. Although children share these causes, ~30% of children have an underlying metabolic, syndromic, or neuromuscular condition causing their cardiomyopathy, making the aetiologies more diverse in children as compared with adults. Although some children present with obvious signs or symptoms of metabolic, syndromic, or neuromuscular disease, other cases may be quite subtle, requiring a high level of suspicion in order to diagnose them. In general, the younger the child, the more extensive the differential. Advantages of identifying the underlying genetic cause of cardiomyopathy in the paediatric population include confirming the diagnosis in ambiguous cases, facilitating appropriate surveillance and management of cardiac and extra-cardiac diseases, providing prognostic information, and establishing the genetic basis in the family, thereby allowing the identification of at-risk relatives and institution of appropriate family screening as indicated. For these reasons, genetic testing is increasingly recognised as standard of care, and guidelines for genetic counselling, testing, and incorporation of family-based risk assessment have been established. Therapies aimed at treating specific genetic aetiologies of cardiomyopathy are emerging and are exciting new developments that require increasingly sophisticated approaches to diagnosis. As genetic testing capabilities continue to expand technically, careful interpretation, knowledgeable clinical utilisation, and appropriate dissemination of genetic information are important and challenging components of clinical care

    The coaching interaction patterns of a college volleyball coach with her high-skilled, average-skilled, and low-skilled athletes

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    This investigation was conducted to determine if the coaching interaction patterns of a head volleyball coach differed significantly with varsity volleyball players with high skill, with average skill, and with low skill ability. [This is an excerpt from the abstract. For the complete abstract, please see the document.

    Efficacy of in-home Parent -Child Interaction Therapy

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    In recent years, there has been much discussion of the efficacy and effectiveness of mental health interventions for children as well as the transportation of empirically-supported treatments (ESTs) to field settings. While there have been efforts to improve dissemination of ESTs, little research has examined the efficacy of treatments in settings other than the traditional clinic. A logical initial step in this line of research is to examine whether the efficacy of ESTs can be demonstrated in community settings such as in the home environment. There are many hypothesized benefits to providing services in the home setting. Based on the promise of this approach, there are a multitude of home-based programs focused on an array of child outcomes (e.g., child development, child health, child abuse prevention) with various levels of success. Despite the potential of this treatment modality, few ESTs have been evaluated in the home setting. One EST that has examined efficacy in the home setting is Behavioral Parent Training (BPT). Parent-Child Interaction Therapy (PCIT) is one such BPT program designed to help families of children with disruptive behavior problems. The purpose of the study was to examine the efficacy of an in-home PCIT program using a single-subject, A/B design across subjects with staggered baselines. Five caregiver-child dyads were recruited for the study, and three completed treatment. Decreases in caregiver use of negative behavior and caregiver-reported child behavior problems were observed for completers. In addition, completers demonstrated increases in child compliance, caregiver use of positive behavior, and contingent praise. Data regarding caregivers\u27 reported parenting stress and caregiver proportion of direct commands was less convincing. All three dyads completing treatment reported satisfaction with the intervention. Clinical implications and future research directions are discussed

    Genetics of paediatric cardiomyopathies

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    PURPOSE OF REVIEW: Paediatric cardiomyopathy is a rare disease with a genetic basis. The purpose of this review is to discuss the current status of genetic findings in the paediatric cardiomyopathy population and present recent progress in utilizing this information for management and therapy. RECENT FINDINGS: With increased clinical genetic testing, an understanding of the genetic causes of cardiomyopathy is improving and novel causes are identified at a rapid rate. Recent progress in identifying the scope of genetic variation in large population datasets has led to reassessment and refinement of our understanding of the significance of rare genetic variation. As a result, the stringency of variant interpretation has increased, at times leading to revision of previous mutation results. Transcriptome and epigenome studies are elucidating important pathways for disease progression and highlight similarities and differences in pathogenesis from adult cardiomyopathy. Therapy targeted towards the underlying cause of cardiomyopathy is emerging for a number of rare syndromes such as Pompe and Noonan syndromes, and genome editing and induced pluripotent stem cells provide promise for additional precision medicine approaches. SUMMARY: Genetics is moving at a rapid pace in paediatric cardiomyopathy. Genetic testing is increasingly being incorporated into clinical care. Although interpretation of rare genetic variation remains challenging, the opportunity to provide management and therapy targeted towards the underlying genetic cause is beginning to be realized

    Intentional Pass: Analyzing Baseball\u27s Antitrust Exemption as Applied to Broadcasting Agreements in Laumann v. National Hockey League

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    For more than a half-century, Major League Baseball\u27s exemption from antitrust laws has intrigued sports fans and legal scholars alike. It seems only fitting that America\u27s pastime would have an exemption with origins as mysterious and debated as the sport itself. Created by the Supreme Court and reinforced by Congress, the baseball exemption in the modern era continues to generate litigation. Like an umpire determining whether a baseball is fair or foul, courts today must judge the boundaries of baseball\u27s exemption. Major League Baseball\u27s owners may benefit from the exemption, but its fans often pay the price. The League has divided the United States into different geographic television markets, which makes it more difficult for fans to watch out-of-market broadcasts. Upset over this policy, fans sued Major League Baseball in 2012 and alleged its broadcast policy unreasonably restrains trade, in violation of antitrust laws. In August of 2014, Judge Shira Scheindlin, in the Southern District of New York, denied Major League Baseball\u27s motion for summary judgment. To the detriment of baseball fans, this Note argues that baseball broadcasting falls within the broad business of baseball exemption to antitrust laws. This Note provides an overview of the baseball exemption, including its origins and developments in the judicial system. It also analyzes and challenges Judge Scheindlin\u27s view of the exemption. As technology develops, litigation over the exemption will involve baseball activities, like broadcasting, that could have never been imagined when the exemption was first enacted, so understanding its boundaries is critical
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