The apparent shape of the "Str\"omgren sphere'' around the highest-redshift QSOs with Gunn-Peterson troughs

Although the highest redshift QSOs (z>6.1) are embedded in a significantly neutral background universe (mass-averaged neutral hydrogen fraction >1%) as suggested by the Gunn-Peterson absorption troughs in their spectra, the intergalactic medium in their vicinity is highly ionized. The highly ionized region is generally idealized as spherical and called the Str\"omgren sphere. In this paper, by combining the expected evolution of the Str\"omgren sphere with the rule that the speed of light is finite, we illustrate the apparent shape of the ionization fronts around the highest redshift QSOs and its evolution, which depends on the age, luminosity evolution, and environment of the QSO (e.g., the hydrogen reionization history). The apparent shape may systematically deviate from a spherical shape, unless the QSO age is significantly long compared to the hydrogen recombination process within the ionization front and the QSO luminosity evolution is significantly slow. Effects of anisotropy of QSO emission are also discussed. The apparent shape of the "Str\"omgren sphere'' may be directly mapped by transmitted spectra of background sources behind or inside the ionized regions or by surveys of the hyperfine transition (21cm) line emission of neutral hydrogen.Comment: 7 pages, 5 figures; discussion on effects of anisotropy of QSO emission expanded; ApJ in pres

Oral Contraceptive Use and Clinical Outcomes in Patients with Multiple Sclerosis

Experimental and clinical data suggest a role of sex steroids in the pathogenesis of multiple sclerosis (MS). Scant information is available about the potential effect of oral contraceptive (OC) use on the prognosis of the disease. We aimed to evaluate this. The study population consisted of 132 women with relapsing-remitting MS before receiving disease modifying treatment and a mean disease duration 6.2 (SD 5.1) years. Three groups of patients were distinguished according to their OC behavior: [1] never-users, patients who never used OC [2] past-users, patients who stopped OC use before disease onset, and [3] after-users, those who used these drugs after disease onset. Multiple linear and logistic regression models were used to analyze the association between oral contraceptive use and annualized relapse rates, disability accumulation and severity of the disease. After-user patients had lower Expanded Disability Status Scale (EDSS) and Multiple Sclerosis Severity Score (MSSS) values than never users (p<0.001 and p=0.002, respectively) and past users (p=0.010 and p=0.002, respectively). These patients were also more likely to have a benign disease course (MSSS<2.5) than never and past users together (OR: 4.52, 95%CI: 2.13-9.56, p<0.001). This effect remained significant after adjustment for confounders, including smoking and childbirths (OR: 2.97, 95%CI: 1.24, 6.54, p=0.011 and for MSSS β: -1.04; 95% C.I. -1.78, -0.30, p=0.006). These results suggest that OC use in women with relapsing-remitting MS is possible associated with a milder disabling disease course

Angiotensin II and tumour necrosis factor α as mediators of ATP-dependent potassium channel remodelling in post-infarction heart failure

Aims Angiotensin II (Ang II) and tumour necrosis factor α (TNFα) are involved in the progression from compensated hypertrophy to heart failure. Here, we test their role in the remodelling of ATP-dependent potassium channel (KATP) in heart failure, conferring increased metabolic and diazoxide sensitivity. Methods and results We observed increased expression of both angiotensinogen and TNFα in the failing rat myocardium, with a regional gradient matching that of the KATP subunit Kir6.1 expression. Both angiotensinogen and TNFα expression correlated positively with Kir6.1 and negatively with Kir6.2 expression across the post-infarction myocardium. To further identify a causal relationship, cardiomyocytes isolated from normal rat hearts were exposed in vitro to Ang II or TNFα. We observed increased Kir6.1 and SUR subunit and reduced Kir6.2 subunit mRNA expression in cardiomyocytes cultured with Ang II or TNFα, similar to what was observed in failing hearts. In patch-clamp experiments, cardiomyocytes cultured with Ang II or TNFα exhibited responsiveness to diazoxide, in terms of both KATP current and action potential shortening. This was not observed in untreated cardiomyocytes and resembles the diazoxide sensitivity of failing cardiomyocytes that also overexpress Kir6.1. Ang II exerted its effect through induction of TNFα expression, because TNFα-neutralizing antibody abolished the effect of Ang II, and in failing hearts, regional expression of angiotensinogen matched TNFα expression. Finally, Ang II and TNFα regulated KATP subunit expression, possibly through differential expression of Forkhead box transcription factors. Conclusion This study identifies Ang II and TNFα as mediators of the remodelling of KATP channels in heart failur

SN 2007od: A Type IIP SN with Circumstellar Interaction

SN 2007od exhibits characteristics that have rarely been seen in a Type IIP supernova (SN). Optical V band photometry reveals a very steep brightness decline between the plateau and nebular phases of ~4.5 mag, likely due to SN 2007od containing a low mass of 56Ni. The optical spectra show an evolution from normal Type IIP with broad Halpha emission, to a complex, four component Halpha emission profile exhibiting asymmetries caused by dust extinction after day 232. This is similar to the spectral evolution of the Type IIn SN 1998S, although no early-time narrow (~200 km s-1) Halpha component was present in SN 2007od. In both SNe, the intermediate-width Halpha emission components are thought to arise in the interaction between the ejecta and its circumstellar medium (CSM). SN 2007od also shows a mid-IR excess due to new dust. The evolution of the Halpha profile and the presence of the mid-IR excess provide strong evidence that SN 2007od formed new dust before day 232. Late-time observations reveal a flattening of the visible lightcurve. This flattening is a strong indication of the presence of a light echo, which likely accounts for much of the broad, underlying Halpha component seen at late-times. We believe the multi-peaked Halpha emission is consistent with the interaction of the ejecta with a circumstellar ring or torus (for the inner components at \pm1500 km s-1), and a single blob or cloud of circumstellar material out of the plane of the CSM ring (for the outer component at -5000 km s-1). The most probable location for the formation of new dust is in the cool dense shell created by the interaction between the expanding ejecta and its CSM. Monte Carlo radiative transfer modeling of the dust emission from SN 2007od implies that up to 4x 10-4Msun of new dust has formed. This is similar to the amounts of dust formed in other CCSNe such as SNe 1999em, 2004et, and 2006jc.Comment: 35 pages, 6 figures. Accepted for publication in Ap

Разработка иммуноферментной тест-системы для анализа иммуногенности вакцины против вирусного гепатита А

Разработка качественного непрямого метода иммуноферментного анализа для выявления титра антител, специфичных к вирусу гепатита А, у вакцинированных мышейDevelopment of a qualitative indirect method of enzyme immunoassay for detecting the titer of antibodies specific to the hepatitis a virus in vaccinated mic

Physical-preparation recommendations for elite rugby sevens performance

Rugby sevens, a sport new to the Olympics, features high-intensity intermittent running and contact efforts more than short match durations, normally 6 times across 2 to 3 d in a tournament format. Elite rugby sevens seasons often include over a dozen competitive tournaments over less than 9 months, demanding deliberate and careful training-stress balance and workload management alongside development of the necessary physical qualities required for competition. Focus on running and repeated power skills, strength, and match-specific conditioning capacities is advised. Partial taper approaches in combination with high-speed running (>5 m/s from GPS measures) before and between tournaments in succession may reduce injury rates and enhance performance. In a sport with substantial long-haul intercontinental travel and repetitive chronic load demands, management of logistics including nutrition and recovery is inclusive of the formula for success in the physical preparation of elite rugby sevens athletes

Observation of light echoes around very young stars

The goal of the paper is to present new results on light echoes from young stellar objects. Broad band CCD images were obtained over three months at one-to-two week intervals for the field of NGC 6726, using the large field-of-view remotely-operated telescope on top of Cerro Burek. We detected scattered light echoes around two young, low-amplitude, irregular variable stars. Observations revealed not just one, but multiple light echoes from brightness pulses of the T Tauri star S CrA and the Herbig Ae/Be star R CrA. Analysis of S CrA's recurring echoes suggests that the star is located 138 +/- 16 pc from Earth, making these the closest echoes ever detected. The environment that scatters the stellar light from S CrA is compatible with an incomplete dust shell or an inclined torus some 10,000 AU in radius and containing $\sim$ $2 \times 10^{-3}$ M_{\sun} of dust. The cause of such concentration at $\sim$ 10,000AU from the star is unknown. It could be the remnant of the envelope from which the star formed, but the distance of the cloud is remarkably similar to the nominal distance of the Oort cloud to the Sun, leading us to also speculate that the dust (or ice) seen around S CrA might have the same origin as the Solar System Oort cloud.Comment: A&A, in press Received: 16 March 2010 / Accepted: 01 June 201

Nonlinear beam self-cleaning in a coupled cavity composite laser based on multimode fiber

We study a coupled cavity laser configuration where a passively Q-switched Nd:YAG microchip laser is combined with an extended cavity, including a doped multimode fiber. For appropriate coupling levels with the extended cavity, we observed that beam selfcleaning was induced in the multimode fiber thanks to nonlinear modal coupling, leading to a quasi-single mode laser output. In the regime of beam self-cleaning, laser pulse duration was reduced from 525 to 225 ps. We also observed a Q-switched mode-locked operation, where spatial self-cleaning was accompanied by far-detuned nonlinear frequency conversion in the active multimode fiber