The nonlinear development of the relativistic two-stream instability

The two-stream instability has been mooted as an explanation for a range of astrophysical applications from GRBs and pulsar glitches to cosmology. Using the first nonlinear numerical simulations of relativistic multi-species hydrodynamics we show that the onset and initial growth of the instability is very well described by linear perturbation theory. In the later stages the linear and nonlinear description match only qualitatively, and the instability does not saturate even in the nonlinear case by purely ideal hydrodynamic effects.Comment: 15 pages, 9 figure

ELECTROMYOGRAPHY ANALYSIS OF FOREARM MUSCLES DURING VARIOUS YOGA POSES

The current study examined muscle activity via electromyography of the flexor carpi radialis (FCR), ulnaris (FCU), and extensor carpi radialis (ECR), ulnaris (ECU) during two variations of three separate yoga poses. Nine participants (n=9) performed three different yoga poses: plank, side-plank, and upward dog; in two separate variations, (V1) with the wrists in a passive hyperextended position, and (V2) with the wrists in a neutral position where the participants made a fist and performed the pose in that position. There were no differences between poses or variations for ECR. A difference was found between variations, but not poses for ECU. FCR and FCU were different between poses, but not variations. The only interaction was for the FCR. Due to the increased muscle activity in V2, performing yoga in V1 position may allow a yoga session to be completed with less fatigue and risk for injury

JOINT ANGLES AND FORCES ON WRIST STRUCTURES DURING VARIATIONS OF YOGA POSES

The current study analysed joint angles of the wrists and forces on the structures in the hands and wrists in a hyperextended position and a neutral position during three different yoga poses. Participants (n = 9) performed three yoga poses (plank, side plank, and upward dog), with their wrists in a hyperextended position (H) and a neutral position (N). Each pose was completed three times for 10 seconds in H and N, for a total of six trials per pose. A two-way Repeated Measures ANOVA found significant differences in both wrist joint angles and GRF between H and N. Due to the suggested path transmission of forces, as well as the increased longitudinal loading that comes with wrist hyperextension, it is recommended that plank, side plank, and upward dog be performed in a neutral wrist position

Facebook as a recruitment tool for adolescent health research: A systematic review

BACKGROUND: Researchers are increasingly using social media to recruit participants to surveys and clinical studies. However, the evidence of the efficacy and validity of adolescent recruitment through Facebook is yet to be established. OBJECTIVE: To conduct a systematic review of the literature on the use of Facebook to recruit adolescents for health research. DATA SOURCES: Nine electronic databases and reference lists were searched for articles published between 2004 and 2013. STUDY ELIGIBILITY CRITERIA: Studies were included in the review if: 1) participants were aged 10 to 18 years, 2) studies addressed a physical or mental health issue, 3) Facebook was identified as a recruitment tool, 4) recruitment details using Facebook were outlined in the methods section and considered in the discussion, or information was obtained by contacting the authors, 5) results revealed how many participants were recruited using Facebook, and 6) studies addressed how adolescent consent and/or parental consent was obtained. STUDY APPRAISALS AND SYNTHESIS METHODS: Titles, abstracts, and keywords were scanned and duplicates removed by 2 reviewers. Full text was evaluated for inclusion criteria, and 2 reviewers independently extracted data. RESULTS: The search resulted in 587 publications, of which 25 full-text papers were analyzed. Six studies met all the criteria for inclusion in the review. Three recruitment methods using Facebook was identified: 1) paid Facebook advertising, 2) use of the Facebook search tool, and 3) creation and use of a Facebook Page. CONCLUSIONS: Eligible studies described the use of paid Facebook advertising and Facebook as a search tool as methods to successfully recruit adolescent participants. Online and verbal consent was obtained from participants recruited from Facebook

Crustal failure during binary inspiral

We present the first fully relativistic calculations of the crustal strain induced in a neutron star by a binary companion at the late stages of inspiral, employing realistic equations of state for the fluid core and the solid crust. We show that while the deep crust is likely to fail only shortly before coalescence, there is a large variation in elastic strain, with the outermost layers failing relatively early on in the inspiral. We discuss the significance of the results for both electromagnetic and gravitational-wave astronomy.Comment: 5 pages, 3 eps figure

Access 3 project protocol: Young people and health system navigation in the digital age: A multifaceted, mixed methods study

© 2017 Article author(s). Background: The integration of digital technology into everyday lives of young people has become widespread. It is not known whether and how technology influences barriers and facilitators to healthcare, and whether and how young people navigate between face-to-face and virtual healthcare. To provide new knowledge essential to policy and practice, we designed a study that would explore health system access and navigation in the digital age. The study objectives are to: (1) describe experiences of young people accessing and navigating the health system in New South Wales (NSW), Australia; (2) identify barriers and facilitators to healthcare for young people and how these vary between groups; (3) describe health system inefficiencies, particularly for young people who are marginalised; (4) provide policy-relevant knowledge translation of the research data. Methods and analysis: This mixed methods study has four parts, including: (1) a cross-sectional survey of young people (12-24 years) residing in NSW, Australia; (2) a longitudinal, qualitative study of a subsample of marginalised young people (defined as young people who: identify as Aboriginal and/or Torres Strait Islander; are experiencing homelessness; identify as sexuality and/or gender diverse; are of refugee or vulnerable migrant background; and/or live in rural or remote NSW); (3) interviews with professionals; (4) a knowledge translation forum. Ethics and dissemination: Ethics approvals were sought and granted. Data collection commenced in March 2016 and will continue until June 2017. This study will gather practice and policy-relevant intelligence about contemporary experiences of young people and health services, with a unique focus on five different groups of marginalised young people, documenting their experiences over time. Access 3 will explore navigation around all levels of the health system, determine whether digital technology is integrated into this, and if so how, and will translate findings into policy-relevant recommendations

Dynamical non-axisymmetric instabilities in rotating relativistic stars

We present new results on dynamical instabilities in rapidly rotating neutron-stars. In particular, using numerical simulations in full General Relativity, we analyse the effects that the stellar compactness has on the threshold for the onset of the dynamical bar-mode instability, as well as on the appearance of other dynamical instabilities. By using an extrapolation technique developed and tested in our previous study [1], we explicitly determine the threshold for a wide range of compactnesses using four sequences of models of constant baryonic mass comprising a total of 59 stellar models. Our calculation of the threshold is in good agreement with the Newtonian prediction and improves the previous post-Newtonian estimates. In addition, we find that for stars with sufficiently large mass and compactness, the m=3 deformation is the fastest growing one. For all of the models considered, the non-axisymmetric instability is suppressed on a dynamical timescale with an m=1 deformation dominating the final stages of the instability. These results, together with those presented in [1], suggest that an m=1 deformation represents a general and late-time feature of non-axisymmetric dynamical instabilities both in full General Relativity and in Newtonian gravity.Comment: To appear on CQG, NFNR special issue. 16 pages, 5 color figures, movies from http://www.fis.unipr.it/numrel/BarMode/ResearchBarMode.htm

Limited sampling estimates of epigallocatechin gallate exposures in cirrhotic and noncirrhotic patients with hepatitis C after single oral doses of green tea extract.

BACKGROUND: Epigallocatechin-3-gallate (EGCG) has antiangiogenic, antioxidant, and antifibrotic properties that may have therapeutic potential for the treatment of cirrhosis induced by hepatitis C virus (HCV). However, cirrhosis might affect EGCG disposition and augment its reported dose-dependent hepatotoxic potential. OBJECTIVE: The safety, tolerability, and disposition of a single oral dose of EGCG in cirrhotic patients with HCV were examined in an exploratory fashion. METHODS: Eleven patients with hepatitis C and detectable viremia were enrolled. Four had Child-Pugh (CP) class A cirrhosis, 4 had Child-Pugh class B cirrhosis, and 3 were noncirrhotic. After a single oral dose of green tea extract 400 mg containing 94% pure EGCG, blood for EGCG levels and safety parameters was ascertained at 2, 4, and 10 hours. RESULTS: C(max) and AUC to EGCG overlapped among the 3 groups, which suggests that the disposition of EGCG was not significantly altered in these patients with cirrhosis. CONCLUSIONS: A single 400-mg oral dose of EGCG was safe and well tolerated by all of the patients in the study. These results provide guidance for the continued investigation of the long-term safety and antitumor potential of EGCG in cirrhotic patients with HCV

Intersectionality: Social Marginalisation and Self-Reported Health Status in Young People.

BACKGROUND:The aim of this study was to measure young people's health status and explore associations between health status and belonging to one or more socio-culturally marginalised group. METHODS:part of the Access 3 project, this cross-sectional survey of young people aged 12-24 years living in New South Wales, Australia, oversampled young people from one or more of the following groups: Aboriginal and or Torres Strait Islander; living in rural and remote areas; homeless; refugee; and/or, sexuality and/or gender diverse. This paper reports on findings pertaining to health status, presence of chronic health conditions, psychological distress, and wellbeing measures. RESULTS:1416 participants completed the survey; 897 (63.3%) belonged to at least one marginalised group; 574 (40.5%) to one, 281 (19.8%) to two and 42 (3.0%) to three or four groups. Belonging to more marginalised groups was significantly associated with having more chronic health conditions (p = 0.001), a greater likelihood of high psychological distress (p = 0.001) and of illness or injury related absence from school or work (p < 0.05). CONCLUSIONS:increasing marginalisation is associated with decreasing health status. Using an intersectional lens can to be a useful way to understand disadvantage for young people belonging to multiple marginalised groups