7,857 research outputs found
The Evolving Relationships Between Hospital, Physician and Patient in Modern American Healthcare
This article explores the ways in which health care has evolved over the past few years for patients, doctors and hospitals in the United States, and the impact these changes have made on modern American health care. As the amount of money the nation spends on health care continues to increase at alarming rates, patients, doctors, and hospitals all appear to have greater struggles than before.This inherent disconnection between the changes in American health care system and the satisfaction of patients and providers leaves much to be desired and considered. Before a solution can be found, however, we must first understand the problem
Big end bearing losses with thermal cavitation flow under cylinder deactivation
The paper presents a mixed thermo-hydrodynamic analysis of elliptic bore bearings using combined solution of Navier–Stokes, continuity and energy equations for multi-phase flow conditions. A vapour transport equation is also included to ensure continuity of flow in the cavitation region for the multiple phases as well as Rayleigh–Plesset to take into account the growth and collapse of cavitation bubbles. This approach removes the need to impose artificial outlet boundary conditions in the form of various cavitation algorithms which are often employed to deal with lubricant film rupture and reformation. The predictions show closer conformance to experimental measurements than have hitherto been reported in the literature. The validated model is then used for the prediction of frictional power losses in big end bearings of modern engines under realistic urban driving conditions. In particular, the effect of cylinder deactivation (CDA) upon engine bearing efficiency is studied. It is shown that big-end bearings losses contribute to an increase in the brake specific fuel consumption with application of CDA contrary to the gains made in fuel pumping losses to the cylinders. The study concludes that implications arising from application of new technologies such as CDA should also include their effect on tribological performance
An Auto-Offset-Removal circuit for chemical sensing based on the PG-ISFET
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Reaction kinetics of muonium with the halogen gases (F2, Cl2, and Br2)
Copyright @ 1989 American Institute of PhysicsBimolecular rate constants for the thermal chemical reactions of muonium (Mu) with the halogen gases—Mu+X2→MuX+X—are reported over the temperature ranges from 500 down to 100, 160, and 200 K for X2=F2,Cl2, and Br2, respectively. The Arrhenius plots for both the chlorine and fluorine reactions show positive activation energies Ea over the whole temperature ranges studied, but which decrease to near zero at low temperature, indicative of the dominant role played by quantum tunneling of the ultralight muonium atom. In the case of Mu+F2, the bimolecular rate constant k(T) is essentially independent of temperature below 150 K, likely the first observation of Wigner threshold tunneling in gas phase (H atom) kinetics. A similar trend is seen in the Mu+Cl2 reaction. The Br2 data exhibit an apparent negative activation energy [Ea=(−0.095±0.020) kcal mol−1], constant over the temperature range of ∼200–400 K, but which decreases at higher temperatures, indicative of a highly attractive potential energy surface. This result is consistent with the energy dependence in the reactive cross section found some years ago in the atomic beam data of Hepburn et al. [J. Chem. Phys. 69, 4311 (1978)]. In comparing the present Mu data with the corresponding H atom kinetic data, it is found that Mu invariably reacts considerably faster than H at all temperatures, but particularly so at low temperatures in the cases of F2 and Cl2. The current transition state calculations of Steckler, Garrett, and Truhlar [Hyperfine Interact. 32, 779 (986)] for Mu+X2 account reasonably well for the rate constants for F2 and Cl2 near room temperature, but their calculated value for Mu+Br2 is much too high. Moreover, these calculations seemingly fail to account for the trend in the Mu+F2 and Mu+Cl2 data toward pronounced quantum tunneling at low temperatures. It is noted that the Mu kinetics provide a crucial test of the accuracy of transition state treatments of tunneling on these early barrier HX2 potential energy surfaces.NSERC (Canada), Donors of the Petroleum Research Fund, administered by the American Chemical Society, for their partial support of this research and the Canada Council
Toll-like receptor variation in the bottlenecked population of the Seychelles warbler: computer simulations see the ‘ghost of selection past’ and quantify the ‘drift debt’
Balancing selection can maintain immunogenetic variation within host populations, but detecting its signal in a post-bottlenecked population is challenging due to the potentially overriding effects of drift. Toll-like receptor genes (TLRs) play a fundamental role in vertebrate immune defence and are predicted to be under balancing selection. We previously characterised variation at TLR loci in the Seychelles warbler (Acrocephalus sechellensis), an endemic passerine that has undergone a historical bottleneck. Five out of seven TLR loci were polymorphic, which is in sharp contrast to the low genome-wide variation observed. However standard population genetic statistical methods failed to detect a contemporary signature of selection at any TLR loci. We examined whether the observed TLR polymorphism could be explained by neutral evolution, simulating the population's demography in the software DIYABC. This showed that the posterior distributions of mutation rates had to be unrealistically high to explain the observed genetic variation. We then conducted simulations with an agent-based model using typical values for the mutation rate, which indicated that weak balancing selection has acted on the three TLR genes. The model was able to detect evidence of past selection elevating TLR polymorphism in the pre-bottleneck populations, but was unable to discern any effects of balancing selection in the contemporary population. Our results show drift is the overriding evolutionary force that has shaped TLR variation in the contemporary Seychelles warbler population, and the observed TLR polymorphisms might be merely the ‘ghost of selection past’. Forecast models predict immunogenetic variation in this species will continue to be eroded in the absence of contemporary balancing selection. Such ‘drift debt’ occurs when a genepool has not yet reached its new equilibrium level of polymorphism, and this loss could be an important threat to many recently bottlenecked populations
Seasonal Change in Countermovement Jump Performance in NCAA Women’s Golfers
Background of Study: The countermovement vertical jump (CMJ) task has been reported to have positive associations with golf-specific performance variables. Additionally, the CMJ is commonly used to assess neuromuscular fatigue in athletic populations. Objective: Thus, this investigation sought to examine the changes in CMJ performance throughout a competitive season in NCAA collegiate women’s golfers. Methods: Using a longitudinal study design, six collegiate women golfers completed three sessions (pre, mid, and post) of CMJ testing during the spring competition period. During each testing session, two successful jump trials were collected using a portable force platform sampling at 1000 Hz. During each trial, an arm swing was restricted by the use of a dowel placed across the upper back. A one-way repeated measures analysis of variance was used to determine if differences were present between testing sessions. Results: Propulsive net impulse significantly increased from pre to mid (p 0.05) and pre to post (p 0.05). No other variables showed a statistically significant change over the duration of the study, though moderate effect size increases were in countermovement depth from pre to mid-testing (0.73) and jump height from pre to post-testing (0.72). Conclusions: These findings support previous findings of an increase in vertical jump performance over the course of a season in collegiate golfers, though strategies for maximal performance may shift
Unhealthy weight control behaviours in adolescent girls: a process model based on self-determination theory
This study used self-determination theory (Deci, E.L., & Ryan, R.M. (2000). The 'what' and 'why' of goal pursuits: Human needs and the self-determination of behavior. Psychological Inquiry, 11, 227-268.) to examine predictors of body image concerns and unhealthy weight control behaviours in a sample of 350 Greek adolescent girls. A process model was tested which proposed that perceptions of parental autonomy support and two life goals (health and image) would predict adolescents' degree of satisfaction of their basic psychological needs. In turn, psychological need satisfaction was hypothesised to negatively predict body image concerns (i.e. drive for thinness and body dissatisfaction) and, indirectly, unhealthy weight control behaviours. The predictions of the model were largely supported indicating that parental autonomy support and adaptive life goals can indirectly impact upon the extent to which female adolescents engage in unhealthy weight control behaviours via facilitating the latter's psychological need satisfaction
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Motherhood, Moral Authority and the Charismatic Matriarch in the Aftermath of Lethal Violence
Images of maternal suffering are an evocative and powerful means of communication in a world where the private grief of victims has increasingly become subject to commodification and public consumption. This article looks at the influence of bereaved mothers as symbols of respect, peace and dignity in the aftermath of violence, and as a result their persuasive presence in family activism. Drawing upon two case studies, this article explores the importance of victims’ stories in public life and, in particular, the presence of the charismatic matriarch in creating communities of solidarity, raising awareness of harms that have previously gone unheard and prompting policy change. It considers the ‘canonical’ story of the mother in public life and concludes by arguing that more attention should be paid to victims’ stories and their influence on policy-making, politics and eventually in becoming public grievances
Aging time affects color stability and sensory properties of ground beef patties adjusted
Palatability traits of flavor, juiciness, and tenderness are associated with consumer satisfaction. Although grinding offers an opportunity to mechanically minimize differences in tenderness, muscle source and product quality may still affect the sensory properties of ground beef. The objective of this study was to determine the effects of two quality grades (Premium Choice and Select) and vacuum storage aging time (7, 21, and 42 days) before processing on ground beef patty display color from chuck roll and knuckle subprimals combined to obtain a common percentage of fat
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