6,761 research outputs found
Coupling of Two Motor Proteins: a New Motor Can Move Faster
We study the effect of a coupling between two motor domains in
highly-processive motor protein complexes. A simple stochastic discrete model,
in which the two parts of the protein molecule interact through some energy
potential, is presented. The exact analytical solutions for the dynamic
properties of the combined motor species, such as the velocity and dispersion,
are derived in terms of the properties of free individual motor domains and the
interaction potential. It is shown that the coupling between the motor domains
can create a more efficient motor protein that can move faster than individual
particles. The results are applied to analyze the motion of helicase RecBCD
molecules
Air pollution, pulmonary oxidative stress, and the endothelin system in the development of cardiovascular injury.
The goal of this project was to examine the role of endothelin-1 (ET-1) as a mediator in the pathway between air pollution exposure and the development of vascular injury. A human cohort and male mice (C57BL/6 and ecSOD-Tg) were used to evaluate changes in the ET-1 system in response to exposures of fine particulate matter (PM2.5). Human ET-1 levels were significantly associated with environmental factors and markers of vascular change, but were decreased with increased PM2.5. No association was seen between ET-1 and endothelial progenitor cells (EPCs) except for EPC-4, possibly indicating a regulatory relationship with this specific population. In mice, the expression of the ET-1 system in the cardiopulmonary tissues changed significantly with exposure, with changes varying between exposure conditions. A potentially protective effect was seen in the lungs of ecSOD-Tg animals. These data suggest that ET-1 plays an important role in the vascular response to PM2.5 exposure
Short communications: Should the Brown-headed Apalis Apalis alticola be on the Kenya list?
No abstrac
Non-Perturbative One-Loop Effective Action for Electrodynamics in Curved Spacetime
In this paper we explicitly evaluate the one-loop effective action in four
dimensions for scalar and spinor fields under the influence of a strong,
covariantly constant, magnetic field in curved spacetime. In the framework of
zeta function regularization, we find the one-loop effective action to all
orders in the magnetic field up to linear terms in the Riemannian curvature. As
a particular case, we also obtain the one-loop effective action for massless
scalar and spinor fields. In this setting, we found that the vacuum energy of
charged spinors with small mass becomes very large due entirely by the
gravitational correction.Comment: LaTeX, 23 page
Investigating people: a qualitative analysis of the search behaviours of open-source intelligence analysts
The Internet and the World Wide Web have become integral parts of the lives of many modern individuals, enabling almost instantaneous communication, sharing and broadcasting of thoughts, feelings and opinions. Much of this information is publicly facing, and as such, it can be utilised in a multitude of online investigations, ranging from employee vetting and credit checking to counter-terrorism and fraud prevention/detection. However, the search needs and behaviours of these investigators are not well documented in the literature. In order to address this gap, an in-depth qualitative study was carried out in cooperation with a leading investigation company. The research contribution is an initial identification of Open-Source Intelligence investigator search behaviours, the procedures and practices that they undertake, along with an overview of the difficulties and challenges that they encounter as part of their domain. This lays the foundation for future research in to the varied domain of Open-Source Intelligence gathering
The Preventing Australian Football Injuries with Exercise (PAFIX) Study: a group randomised controlled trial
Background: Knee injuries are a major injury concern for Australian Football players and participants of many other sports worldwide. There is increasing evidence from laboratory and biomechanically focused studies about the likely benefit of targeted exercise programmes to prevent knee injuries. However, there have been few international studies that have evaluated the effectiveness of such programmes in the real-world context of community sport that have combined epidemiological, behavioural and biomechanical approaches. Objective: To implement a fully piloted and tested exercise training intervention to reduce the number of football-related knee injuries. In so doing, to evaluate the intervention's effectiveness in the real-world context of community football and to determine if the underlying neural and biomechanical training adaptations are associated with decreased risk of injury. Setting: Adult players from community-level Australian Football clubs in two Australian states over the 2007-08 playing seasons. Methods: A group-clustered randomised controlled trial with teams of players randomly allocated to either a coach-delivered targeted exercise programme or usual behaviour (control). Epidemiological component: field- based injury surveillance and monitoring of training/game exposures. Behavioural component: evaluation of player and coach attitudes, knowledge, behaviours and com- pliance, both before and after the intervention is implemented. Biomechanical component: biomechanical, game mobility and neuromuscular parameters assessed to determine the fundamental effect of training on these factors and injury risk. Outcome measures: The rate and severity of injury in the intervention group compared with the control group. Changes, if any, in behavioural components. Process evaluation: coach delivery factors and likely sustainability
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