615 research outputs found

    Comparison of bungee-aided and free-bouncing accelerations on trampoline

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    Trampolines remain the single best apparatus for the training of aerial acrobatics skills. Trampoline use has led to catastrophic injuries from poor landings. Passive injury prevention countermeasures such as specialized matting have been largely ineffective. Active injury countermeasures such as hand spotting, “throw-in” mats, and overhead spotting rigs provide the most effective methods. The recent addition of several bungee cords between the ropes and the gymnast’s spotting harness has resulted in altered teaching and coaching of trampoline-related acrobatics. Bungee cords have eliminated the need for a coach/spotter to manage the ropes during skill learning. The purpose of this study was to assess the influence of the addition of bungee cords with a traditional rope-based overhead spotting rig. There is a paucity of any research involving trampoline injury countermeasures. Ten experienced trampoline acrobatic athletes (5 males, 5 females) from the U.S. Ski and Snowboard Association Aerials National Team performed 10 bounces as high as they could control. A triaxial accelerometer (200 Hz) characterized 10 bungee cord aided bounces and 10 freebounces on a trampoline from each athlete. Bed contact times, peak accelerations, and average accelerations were obtained. The results supported our hypotheses that the bungeeaided bounces achieved only 40% (average) to 70% (peak) of the free-bouncing accelerations (all ρ 0.092). The bed contact time was approximately 65% longer during the bungee-aided bounces (ρ < 0.001). Bungee cords may reduce the harshness of landings on trampoline

    Investigating the Accuracy of One-Dimensional Volcanic Plume Models using Laboratory Experiments and Field Data

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    During volcanic eruptions, model predictions of plume height are limited by the accuracy of entrainment coefficients used in many plume models. Typically, two parameters are used, and , which relate the entrained air speed to the jet speed in the axial and cross-flow directions, respectively. To improve estimates of these parameters, wind tunnel experiments have been conducted for a range of cross-wind velocities and turbulence conditions. Measurements are compared directly to computations from the 1-D plume model, Plumeria, in the near-field, bending region of the jet. Entrainment coefficients are determined through regression analysis, demonstrating optimal combinations of effective and values. For turbulent conditions, all wind speeds overlapped at a single combination, = 0.06 and = 0.46, each of which are slightly reduced from standard values. Refined coefficients were used to model plume heights for 20 historical eruptions. Model accuracy improves modestly in most cases, agreeing to within 3 km with observed plume heights. For weak eruptions, uncertainty in field measurements can outweigh the effects of these refinements, illustrating the challenge of applying plume models in practice

    Bergman kernel and complex singularity exponent

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    We give a precise estimate of the Bergman kernel for the model domain defined by ΩF={(z,w)∈Cn+1:Imw−∣F(z)∣2>0},\Omega_F=\{(z,w)\in \mathbb{C}^{n+1}:{\rm Im}w-|F(z)|^2>0\}, where F=(f1,...,fm)F=(f_1,...,f_m) is a holomorphic map from Cn\mathbb{C}^n to Cm\mathbb{C}^m, in terms of the complex singularity exponent of FF.Comment: to appear in Science in China, a special issue dedicated to Professor Zhong Tongde's 80th birthda

    A PILOT STUDY TO MEASURE FORCE DEVELOPMENT DURING A SIMULATED MALTESE CROSS FOR GYMNASTICS STILL RINGS

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    The purpose of this study was to develop a measurement procedure for the Maltese cross performed on still rings. Sixteen elite/international gymnasts participated. Two small force platforms (FPs) interfaced to a portable data logger (100 Hz sampling rate) were placed under the gymnasts’ hands in a simulated Maltese position (i.e., prone). Gymnasts attempted to rise a few centimeters to a Maltese position while vertical ground reaction forces were recorded bilaterally. Results indicated that the FPs had sufficient fidelity to differentiate gymnasts’ abilities to perform a Maltese. This method may serve to gauge the preparedness of male gymnasts performing this important skill

    A Pilot Study to Measure Force Development during a Simulated Maltese Cross for Gymnastics Still Rings

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    The purpose of this study was to develop a measurement procedure for the Maltese cross performed on still rings. Sixteen elite/international gymnasts participated. Two small force platforms (FPs) interfaced to a portable data logger (100 Hz sampling rate) were placed under the gymnasts’ hands in a simulated Maltese position (i.e., prone). Gymnasts attempted to rise a few centimeters to a Maltese position while vertical ground reaction forces were recorded bilaterally. Results indicated that the FPs had sufficient fidelity to differentiate gymnasts’ abilities to perform a Maltese. This method may serve to gauge the preparedness of male gymnasts performing this important skill

    The Status of Clinical Faculty in the Legal Academy: Report of the Task Force on the Status of Clinicians and the Legal Academy

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    In the midst of ongoing debates within the legal academy and the American Bar Association on the need for \u27practice-ready law school graduates through enhanced attention to law clinics and externships and on the status of faculty teaching in those courses, this report identifies and evaluates the most appropriate modes for clinical faculty appointments. Drawing on data collected through a survey of clinical program directors and faculty, the report analyzes the five most identifiable clinical faculty models: unitary tenure track; clinical tenure track; long-term contract; short-term contract; and clinical fellowships. It determines that, despite great strides in the growth of clinical legal education in the last 30 years, equality between clinical and non-clinical faculty remains elusive. Clinical faculty still lag behind non-clinical faculty in security of position and governance rights at most law schools. The report then identifies four core principles that should guide decisions about clinical faculty appointments: 1) clinical education is a foundational and essential component of legal education; 2) the legal academy and profession benefit from full inclusion of clinical faculty on all matters affecting the mission, function, and direction of law schools; 3) there is no justification for creating hierarchies between clinical and non-clinical faculty; and 4) the standards for hiring, retention, and promotion of clinical faculty must recognize and value the responsibilities and methodologies of clinical teaching. The report concludes that these core principles are best realized when full-time clinical faculty are appointed to a unitary tenure track. This conclusion does not ignore the imperfections of a tenure system. However, to the extent that tenure remains the strongest measure of the legal academy\u27s investment in its faculty and is the surest guarantee of academic freedom, inclusion in faculty governance and job security, the report recommends that law schools predominantly place their clinical faculty on dedicated tenure lines. In addition, it recommends that schools implement standards for hiring, promotion, and retention that reflect the teaching responsibilities and methodologies, as well as practice and service obligations, unique to their clinical faculty. To facilitate the development of such standards, the report suggests good practices for the appointment of clinical faculty on a unitary tenure track

    Serotonin regulates prostate growth through androgen receptor modulation

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    Serotonin regulates prostate growth through androgen receptor modulationAging and testosterone almost inexorably cause benign prostatic hyperplasia (BPH) in Human males. However, etiology of BPH is largely unknown. Serotonin (5-HT) is produced by neuroendocrine prostatic cells and presents in high concentration in normal prostatic transition zone, but its function in prostate physiology is unknown. Previous evidence demonstrated that neuroendocrine cells and 5-HT are decreased in BPH compared to normal prostate. Here, we show that 5-HT is a strong negative regulator of prostate growth. In vitro, 5-HT inhibits rat prostate branching through down-regulation of androgen receptor (AR). This 5-HT's inhibitory mechanism is also present in human cells of normal prostate and BPH, namely in cell lines expressing AR when treated with testosterone. In both models, 5-HT's inhibitory mechanism was replicated by specific agonists of 5-Htr1a and 5-Htr1b. Since peripheral 5-HT production is specifically regulated by tryptophan hydroxylase 1(Tph1), we showed that Tph1 knockout mice present higher prostate mass and up-regulation of AR when compared to wild-type, whereas 5-HT treatment restored the prostate weight and AR levels. As 5-HT is decreased in BPH, we present here evidence that links 5-HT depletion to BPH etiology through modulation of AR. Serotoninergic prostate pathway should be explored as a new therapeutic target for BPH.Projects NORTE-01-0246-FEDER-000012, NORTE-01-0145-FEDER-000013 and NORTE-01-0145-FEDER-000023, supported by the Northern Portugal Regional Operational Program (NORTE 2020), under the Portugal 2020 Partnership Agreement, through the European Regional Development Fund (FEDER) and Bolsa de Investigação GSK Inovação em Urologia 2012info:eu-repo/semantics/publishedVersio

    Utilization of a mobile medical van for delivering pediatric care in the bateys of the Dominican Republic

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    Background Bateys are impoverished areas of housing for migrant Haitian sugar cane workers in the Dominican Republic (DR). In these regions, preventative health care is almost non-existent, public service accessibility is limited, and geographic isolation prevents utilization of care even by those families with resources. Consequently, the development of a viable mobile system is vital to the delivery of acute and preventative health care in this region. Aims This study evaluated an existing mobile medical system. The primary goal was to describe the population served, diseases treated, and resources utilized. A secondary goal was to determine qualitatively an optimal infrastructure for sustainable health care delivery within the bateys. Methods Information on basic demographic data, diagnosis, chronicity of disease, and medications dispensed was collected on all pediatric patients seen in conjunction with an existing mobile medical system over a 3-month period in the DR. Health statistics for the region were collected and interviews were conducted with health care workers (HCWs) and community members on existing and optimal health care infrastructure. Results Five hundred eighty-four pediatric patients were evaluated and treated. Median age was 5 years (range 2 weeks to 20 years), and 53.7% of patients seen were 5 years of age or younger. The mean number of complaints per patient was 2.8 (range 0 to 6). Thirty-six percent (373) of all diagnoses were for acute complaints, and 64% (657) were chronic medical problems. The most common pediatric illnesses diagnosed clinically were gastrointestinal parasitic infection (56.6%), skin/fungal infection (46.2%), upper respiratory tract infections (URIs) (22.8%), previously undiagnosed asthma and allergies (8.2%), and symptomatic anemia (7.2%). Thirty HCWs and community members were interviewed, and all cited the need for similar resources: a community clinic and hospital referral site, health promoters within each community, and the initiation of pediatric training for community HCWs. Conclusion A mobile medical system is a sustainable, efficient mechanism for delivering acute and preventive care in the Haitian bateys of the Dominican Republic. The majority of patients served were 8 years of age or younger with multiple presenting symptoms. A pediatric protocol for identifying the most appropriate drugs and supplies for mobile units in the DR can be created based upon diseases evaluated. Qualitative data from HCWs and community members identified the need for an integrative health care delivery infrastructure and community health promoters versed in pediatric care who can aid in education of batey members and monitor chronic and acute illnesses. We are planning follow-up visits to implement these programs
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