Radiation from a D-dimensional collision of shock waves: first order perturbation theory

We study the spacetime obtained by superimposing two equal Aichelburg-Sexl shock waves in D dimensions traveling, head-on, in opposite directions. Considering the collision in a boosted frame, one shock becomes stronger than the other, and a perturbative framework to compute the metric in the future of the collision is setup. The geometry is given, in first order perturbation theory, as an integral solution, in terms of initial data on the null surface where the strong shock has support. We then extract the radiation emitted in the collision by using a D-dimensional generalisation of the Landau-Lifschitz pseudo-tensor and compute the percentage of the initial centre of mass energy epsilon emitted as gravitational waves. In D=4 we find epsilon=25.0%, in agreement with the result of D'Eath and Payne. As D increases, this percentage increases monotonically, reaching 40.0% in D=10. Our result is always within the bound obtained from apparent horizons by Penrose, in D=4, yielding 29.3%, and Eardley and Giddings, in D> 4, which also increases monotonically with dimension, reaching 41.2% in D=10. We also present the wave forms and provide a physical interpretation for the observed peaks, in terms of the null generators of the shocks.Comment: 27 pages, 11 figures; v2 some corrections, including D dependent factor in epsilon; matches version accepted in JHE

Hydrodynamic Long-Time tails From Anti de Sitter Space

For generic field theories at finite temperature, a power-law falloff of correlation functions of conserved currents at long times is a prediction of non-linear hydrodynamics. We demonstrate, through a one-loop computation in Einstein gravity in Anti de Sitter space, that this effect is reproduced by the dynamics of black hole horizons. The result is in agreement with the gauge-gravity correspondence.Comment: 31 pages, references adde

A review of the distribution of particulate trace elements in urban terrestrial environments and its application to considerations of risk

We review the evolution, state of the art and future lines of research on the sources, transport pathways, and sinks of particulate trace elements in urban terrestrial environments to include the atmosphere, soils, and street and indoor dusts. Such studies reveal reductions in the emissions of some elements of historical concern such as Pb, with interest consequently focusing on other toxic trace elements such as As, Cd, Hg, Zn, and Cu. While establishment of levels of these elements is important in assessing the potential impacts of human society on the urban environment, it is also necessary to apply this knowledge in conjunction with information on the toxicity of those trace elements and the degree of exposure of human receptors to an assessment of whether such contamination represents a real risk to the city’s inhabitants and therefore how this risk can be addressed

Effects of alirocumab on types of myocardial infarction: insights from the ODYSSEY OUTCOMES trial

Aims  The third Universal Definition of Myocardial Infarction (MI) Task Force classified MIs into five types: Type 1, spontaneous; Type 2, related to oxygen supply/demand imbalance; Type 3, fatal without ascertainment of cardiac biomarkers; Type 4, related to percutaneous coronary intervention; and Type 5, related to coronary artery bypass surgery. Low-density lipoprotein cholesterol (LDL-C) reduction with statins and proprotein convertase subtilisin–kexin Type 9 (PCSK9) inhibitors reduces risk of MI, but less is known about effects on types of MI. ODYSSEY OUTCOMES compared the PCSK9 inhibitor alirocumab with placebo in 18 924 patients with recent acute coronary syndrome (ACS) and elevated LDL-C (≥1.8 mmol/L) despite intensive statin therapy. In a pre-specified analysis, we assessed the effects of alirocumab on types of MI. Methods and results  Median follow-up was 2.8 years. Myocardial infarction types were prospectively adjudicated and classified. Of 1860 total MIs, 1223 (65.8%) were adjudicated as Type 1, 386 (20.8%) as Type 2, and 244 (13.1%) as Type 4. Few events were Type 3 (n = 2) or Type 5 (n = 5). Alirocumab reduced first MIs [hazard ratio (HR) 0.85, 95% confidence interval (CI) 0.77–0.95; P = 0.003], with reductions in both Type 1 (HR 0.87, 95% CI 0.77–0.99; P = 0.032) and Type 2 (0.77, 0.61–0.97; P = 0.025), but not Type 4 MI. Conclusion  After ACS, alirocumab added to intensive statin therapy favourably impacted on Type 1 and 2 MIs. The data indicate for the first time that a lipid-lowering therapy can attenuate the risk of Type 2 MI. Low-density lipoprotein cholesterol reduction below levels achievable with statins is an effective preventive strategy for both MI types.For complete list of authors see http://dx.doi.org/10.1093/eurheartj/ehz299</p

Association of human herpes virus 6 (HHV-6) with multiple sclerosis: increased IgM response to HHV-6 early antigen and detection of serum HHV-6 DNA.

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Topographic anatomy of bronchial arteries in the pig: a corrosion cast study

The anatomy of porcine bronchial circulation has not been fully described. The purpose of this study was to investigate the extrapulmonary topographic anatomy of bronchial arteries in pig. Ten pigs weighing 15–25 kg were studied. Between one and four bronchial arteries were found in each pig. The bronchoesophageal artery (BEA), tracheobronchial artery (TBA), inferior bronchial artery (IBA) and accessory bronchial artery (ABA) were present in 10/10, 8/10, 6/10 and 2/10 animals, respectively. The trunk of BEA had a diameter of about 3 mm, a length of 1–7 mm, and originated from the anterior and medial aspect of the descending thoracic aorta at the level between the 2nd and 4th thoracic vertebrae (T(2)–T(4)) in all animals. The extrapulmonary topographic anatomy of bronchial arteries in pigs exhibits similarities to that of humans. BEA is the main blood supplier of the porcine tracheobronchial tree with a relatively constant location of origin and a sufficient size for anastomosis. These characteristics render BEA the ideal vessel for bronchial revascularization in pigs

Autonomia e trabalho do enfermeiro Autonomía y trabajo del enfermero Autonomy and the work of the nurse

Trata-se de um estudo qualitativo, exploratório e descritivo que teve como objetivo descrever as percepções de enfermeiros sobre a autonomia que detém no exercício profissional onde trabalham. Participaram do estudo dez enfermeiros que atuam na área hospitalar ou de atenção primária à saúde. A estratégia adotada para a obtenção dos dados foi a entrevista semi-estruturada. Os dados da pesquisa foram analisados pela técnica de análise de conteúdo e levou a três áreas temáticas: formação do enfermeiro, processos de trabalho da enfermagem e relações interpessoais. Destaca-se a importância que assume o enfermeiro, a partir de sua própria trajetória, no planejamento, organização e direção dos processos de trabalho da enfermagem, especialmente quanto à tomada de decisão para uma atuação autônoma responsável.<br>Este es un estudio cualitativo, exploratorio y descriptivo tuvo como objetivo describir la percepción de enfermeros sobre la autonomía que tienen en la práctica en la que trabajan. Participó en el estudio, diez enfermeros que trabajan en el hospital o de atención primaria a la salud. La estrategia adoptada para obtener los datos fue la entrevista semi-estructurada. Los datos de la encuesta fueron analizados utilizando el análisis de contenido y dirigido a tres áreas temáticas: la educación de enfermería, enfermería procesos de trabajo y las relaciones interpersonales. El estudio destaca la importancia de que las enfermeras, a partir de su propia carrera en la planificación, organización y dirección de los procesos de trabajo de enfermería, especialmente la toma de decisiones en una acción en autonomía responsable.<br>This is a qualitative, exploratory and descriptive study that aimed to describe nurses' perceptions on the autonomy they hold in the practice they work in. Ten nurses working in the hospital or primary care centers participated in the study. A semistructured interview was used to gather data. The data were analyzed using content analysis, which led to three thematic areas: nursing education, nursing work processes and interpersonal relations. The study highlights the importance that nurses and their personal stories have in organizing and directing nursing work processes, especially decision-making in a responsible autonomous action