One loop photon-graviton mixing in an electromagnetic field: Part 2

In part 1 of this series compact integral representations had been obtained for the one-loop photon-graviton amplitude involving a charged spin 0 or spin 1/2 particle in the loop and an arbitrary constant electromagnetic field. In this sequel, we study the structure and magnitude of the various polarization components of this amplitude on-shell. Explicit expressions are obtained for a number of limiting cases.Comment: 31 pages, 3 figure

About Bianchi I with VSL

In this paper we study how to attack, through different techniques, a perfect fluid Bianchi I model with variable G,c and Lambda, but taking into account the effects of a $c$-variable into the curvature tensor. We study the model under the assumption,div(T)=0. These tactics are: Lie groups method (LM), imposing a particular symmetry, self-similarity (SS), matter collineations (MC) and kinematical self-similarity (KSS). We compare both tactics since they are quite similar (symmetry principles). We arrive to the conclusion that the LM is too restrictive and brings us to get only the flat FRW solution. The SS, MC and KSS approaches bring us to obtain all the quantities depending on \int c(t)dt. Therefore, in order to study their behavior we impose some physical restrictions like for example the condition q<0 (accelerating universe). In this way we find that $c$ is a growing time function and Lambda is a decreasing time function whose sing depends on the equation of state, w, while the exponents of the scale factor must satisfy the conditions $\sum_{i=1}^{3}\alpha_{i}=1$ and $\sum_{i=1}^{3}\alpha_{i}^{2}<1,$ $\forall\omega$, i.e. for all equation of state$,$ relaxing in this way the Kasner conditions. The behavior of $G$ depends on two parameters, the equation of state $\omega$ and $\epsilon,$ a parameter that controls the behavior of $c(t),$ therefore $G$ may be growing or decreasing.We also show that through the Lie method, there is no difference between to study the field equations under the assumption of a $c-$var affecting to the curvature tensor which the other one where it is not considered such effects.Nevertheless, it is essential to consider such effects in the cases studied under the SS, MC, and KSS hypotheses.Comment: 29 pages, Revtex4, Accepted for publication in Astrophysics & Space Scienc

Spatiotemporal deficits and kinematic classification of gait following a traumatic brain injury

Objective: To identify the key biomechanical gait abnormalities resulting from traumatic brain injury (TBI) and determine whether the abnormalities support a system for the classification of gait disorders. Design: Systematic review with data from quantitative studies synthesized in a narrative format. Participants: Adults with TBI. Outcome measures: Spatiotemporal, kinematic, and kinetic parameters of classification systems. Results: The search identified 38 articles that reported on various methods for gait assessment in TBI. Three-dimensional gait analysis (3DGA) was used in 15 studies, primarily to quantify spatiotemporal parameters. Results revealed that people with a TBI walked more slowly with shorter steps and greater mediolateral sway following TBI. Stepping over obstacles, walking with eyes closed, or performing dual tasks accentuated gait deficits. Only one small study reported kinematic data for the major lower limb joints in 8 well recovered patients. One further study used 3DGA to classify the gait patterns of people with TBI but this classification was based on methods developed for stroke and cerebral palsy. No studies attempted to develop a classification system on the basis of the gait disorders of people with TBI. Conclusion: Although the studies were generally of high quality, little is known about the nature of gait disorders following TBI. Classification based on systematic description of gait disorders following TBI has not been attempted

Predictive Properties of the Violence Risk Scale–Sexual Offense Version as a Function of Age

The present study examined the discrimination and calibration properties of Violence Risk Scale–Sexual Offense version (VRS-SO) risk and change scores for sexual and violent recidivism as a function of age at release, on a combined sample of 1,287 men who had attended sexual offense-specific treatment services. The key aim was to examine to what extent VRS-SO scores can accurately discriminate recidivists from nonrecidivists among older cohorts, and if the existing age-related adjustments in the instrument adequately correct for increasing age. VRS-SO risk and change scores showed consistent properties of discrimination for sexual recidivism across the age cohorts, via area under the curve and Cox regression survival analysis, as demonstrated through fixed effects meta-analysis. Calibration analyses, employing logistic regression, demonstrated that age at release was consistently incrementally predictive of violent, but not sexual, recidivism after controlling for individual differences on static and dynamic risk factors. E/O index analyses demonstrated that predicted rates of sexual recidivism from VRS-SO scores, particularly when employed with Static-99R, were not significantly different from those observed among age cohorts; however, calibration was weaker for general violence. Implications for use of the VRS-SO in sexual recidivism risk assessment with older offenders are discussed. </jats:p

The clinical assessment of treatment change among sexual offenders, and the relationship between change and risk

Meta-analytic findings are clear that treatment can be effective at reducing sexual reoffending. Yet, a significant proportion of those who complete best-practice programs go on to reoffend (~11%). Not all who complete the same treatment therefore derive the same benefit! Given this, how can we know whether an individual has made relevant change in treatment? How can we know how much change they have made? And, if an individual has made change across treatment, does this mean they are less likely to reoffend