The role of cross-training in swim-related injuries in master’s swimmers

Orthopedic injuries often interfere with Masters athletes’ pursuit of better performance and might place economic burden on these athletes. PURPOSE: We determined if the incidence of injuries increases with age and the economic burden associated with these injuries and whether the participation in cross-training (running, cycling, dryland resistance training) would reduce swim-related injuries in Masters swimmers. METHODS: An online, comprehensive questionnaire was sent to members of United States Masters Swimming (USMS). Response was received from 499 swimmers (294 females, 20-86 years). Economic burden was determined by total healthcare costs. Binary logistic regression was used to compute the odds ratio (OR) of having an injury, using age as a predictor. Linear regression was used to determine the relationship between injury length and healthcare costs. RESULTS: Participants had been swimming for 13.3±11.5 years, and 47%, 35%, and 40% participated in dryland resistance training, running, and cycling, respectively. For every 1 year increase in age, the odds of having an injury increased by 1.6% (OR=1.016, 95% CI= 1.001-1.030; p<0.05). For every 1 month increase in the length of swim-related injury, healthcare costs increased by 7.4% (p<0.05). The OR for having a swim-related injury were significantly less for individuals who participated in each form of cross-training compared with those who did not (p<0.05 for all). The OR for having a swim-related injury was significantly less for those who reported participating in any number of cross-training activities compared with those who did not participate in any (p<0.05 for all). CONCLUSIONS: Swim-related injuries increased with advancing age; with longer injuries leading to higher healthcare costs. Participating in any form or any number of cross-training activities attenuated the odds of having an injury in Masters swimmersKinesiology and Health Educatio

Approximate solutions for the single soliton in a Skyrmion-type model with a dilaton scalar field

We consider the analytical properties of the single-soliton solution in a Skyrmion-type Lagrangian that incorporates the scaling properties of quantum chromodynamics (QCD) through the coupling of the chiral field to a scalar field interpreted as a bound state of gluons. The model was proposed in previous works to describe the Goldstone pions in a dense medium, being also useful for studying the properties of nuclear matter and the in-medium properties of mesons and nucleons. Guided by an asymptotic analysis of the Euler-Lagrange equations, we propose approximate analytical representations for the single soliton solution in terms of rational approximants exponentially localized. Following the Pad\'e method, we construct a sequence of approximants from the exact power series solutions near the origin. We find that the convergence of the approximate representations to the numerical solutions is considerably improved by taking the expansion coefficients as free parameters and then minimizing the mass of the Skyrmion using our ans\"atze for the fields. We also perform an analysis of convergence by computation of physical quantities showing that the proposed analytical representations are very useful useful for phenomenological calculations.Comment: 13 pages, 3 eps figures, version to be published in Phys.Rev.

Sirtuin-1: a new potential therapeutic target for rhinosinusitis? Who 'nose'?

Chronic rhinosinusitis is one of the most common upper respiratory tract diseases. In the USA chronic rhinosinusitis has a high prevalence, with around 12% of the population having the disease, and therefore as a consequence the disease has a high health cost burden (1). Chronic rhinosinusitis is classified as an inflammatory nasal disease in which the nasal cavities become inflamed and swollen. The disease can be divided into two distinct disease phenotypes: Chronic rhinosinusitis without nasal polyps (CRSsNP) and Chronic rhinosinusitis with nasal polyps (CRSwNP) (2). One of the major clinical differences between the two subsets of disease is that CRSwNP patients form nasal polyps within their nasal cavities, with these being described as inflammatory lesions of sinonasal tissue which further narrow this space (3). This leads to symptoms of nasal congestion, rhinorrhoea and facial pressure or pain that is of duration of 12 weeks or longer (3). CRSwNP is believed to be a disease of eosinophilia, with an impaired sinonasal epithelial barrier that causes hypersensitivity to inhaled pathogens and particulates, as well as increased permeability, exacerbating the recruitment of inflammatory cells in response to the stimulus

Towards understanding Regge trajectories in holographic QCD

We reassess a work done by Migdal on the spectrum of low-energy vector mesons in QCD in the light of the AdS-QCD correspondence. Recently, a tantalizing parallelism was suggested between Migdal's work and a family of holographic duals of QCD. Despite the intriguing similarities, both approaches face a major drawback: the spectrum is in conflict with well-tested Regge scaling. However, it has recently been shown that holographic duals can be modified to accomodate Regge behavior. Therefore, it is interesting to understand whether Regge behavior can also be achieved in Migdal's approach. In this paper we investigate this issue. We find that Migdal's approach, which is based on a modified Pade approximant, is closely related to the issue of quark-hadron duality breakdown in QCD.Comment: 17 pages, 1 figure. Typos fixed, references added, improved discussion. Minor changes to match the journal versio

Thermal Characterization Of Carbon Composites

Thermophysical properties of materials such as, thermal conductivity, diffusivity, and specific heat, are very important in engineering design process. For example, thermal conductivity plays a critical role in the performance of materials in high temperature applications and it is essential in the selection of materials when optimum performance is desired. Other thermophysical properties, such as thermal diffusivity and specific heat capacity, play significant roles in design application as they determine safe operating temperature, form process control characteristics, and quality conditions in manufacturing plants. The objective of this research was to determine the thermal properties of carbon composite materials. The materials of interest to this analysis were carbon-carbon and carbon-epoxy composites. The carbon-carbon composites tested were produced by the resin transfer molding process using T300 PAN based carbon fiber and PT-30 cyanate ester matrix. In contrast, the carbon-epoxy composite tested consisted of unidirectional continuous AS4 carbon fiber and 3501-6 amine cured epoxy resin. Following standard ASTM E1461, the flash method was used to measure the thermal diffusivity of the carbon composites. In addition, a differential scanning calorimeter was used in accordance with the ASTM E1269 standard to determine the specific heat. The thermal conductivity of the carbon composites was determined using the measured values of their thermal diffusivity and specific heat, respectively

Design of an inert fluid injection system, phase 3 Final report

Research, development, and design of velocity trim system for third stage of Delta launch vehicl

A Green's function formulation for a nonlinear potential flow solution applicable to transonic flow

Routine determination of inviscid subsonic flow fields about wing-body-tail configurations employing a Green's function approach for numerical solution of the perturbation velocity potential equation is successfully extended into the high subsonic subcritical flow regime and into the shock-free supersonic flow regime. A modified Green's function formulation, valid throughout a range of Mach numbers including transonic, that takes an explicit accounting of the intrinsic nonlinearity in the parent governing partial differential equations is developed. Some considerations pertinent to flow field predictions in the transonic flow regime are discussed