GRB 120422A/SN 2012bz: Bridging the gap between low- and high-luminosity gamma-ray bursts

Context. At low redshift, a handful of gamma-ray bursts (GRBs) have been discovered with luminosities that are substantially lower (Liso ≲ 1048.5 erg s-1) than the average of more distant ones (Liso ≳ 1049.5 erg s-1). It has been suggested that the properties of several low-luminosity (low-L) GRBs are due to shock break-out, as opposed to the emission from ultrarelativistic jets. This has led to much debate about how the populations are connected. Aims. The burst at redshift z = 0.283 from 2012 April 22 is one of the very few examples of intermediate-L GRBs with a γ-ray luminosity of Liso ~ 1049.6−49.9 erg s-1 that have been detected up to now. With the robust detection of its accompanying supernova SN 2012bz, it has the potential to answer important questions on the origin of low- and high-L GRBs and the GRB-SN connection. Methods. We carried out a spectroscopy campaign using medium- and low-resolution spectrographs with 6–10-m class telescopes, which covered a time span of 37.3 days, and a multi-wavelength imaging campaign, which ranged from radio to X-ray energies over a duration of ~270 days. Furthermore, we used a tuneable filter that is centred at Hα to map star-formation in the host and the surrounding galaxies. We used these data to extract and model the properties of different radiation components and fitted the spectral energy distribution to extract the properties of the host galaxy. Results. Modelling the light curve and spectral energy distribution from the radio to the X-rays revealed that the blast wave expanded with an initial Lorentz factor of Γ0 ~ 50, which is a low value in comparison to high-L GRBs, and that the afterglow had an exceptionally low peak luminosity density of ≲2 × 1030 erg s-1 Hz-1 in the sub-mm. Because of the weak afterglow component, we were able to recover the signature of a shock break-out in an event that was not a genuine low-L GRB for the first time. At 1.4 hr after the burst, the stellar envelope had a blackbody temperature of kBT ~ 16 eV and a radius of ~7 × 1013 cm (both in the observer frame). The accompanying SN 2012bz reached a peak luminosity of MV = −19.7 mag, which is 0.3 mag more luminous than SN 1998bw. The synthesised nickel mass of 0.58 M⊙, ejecta mass of 5.87 M⊙, and kinetic energy of 4.10 × 1052 erg were among the highest for GRB-SNe, which makes it the most luminous spectroscopically confirmed SN to date. Nebular emission lines at the GRB location were visible, which extend from the galaxy nucleus to the explosion site. The host and the explosion site had close-to-solar metallicity. The burst occurred in an isolated star-forming region with an SFR that is 1/10 of that in the galaxy’s nucleus. Conclusions. While the prompt γ-ray emission points to a high-L GRB, the weak afterglow and the low Γ0 were very atypical for such a burst. Moreover, the detection of the shock break-out signature is a new quality for high-L GRBs. So far, shock break-outs were exclusively detected for low-L GRBs, while GRB 120422A had an intermediate Liso of ~1049.6−49.9 erg s-1. Therefore, we conclude that GRB 120422A was a transition object between low- and high-L GRBs, which supports the failed-jet model that connects low-L GRBs that are driven by shock break-outs and high-L GRBs that are powered by ultra-relativistic jets

Laparoscopic sleeve gastrectomy on a morbidly obese patient with situs inversus totalis: A case study and systematic review of the literature

PMID = 2803469

Reasons and levels of teachers’ resistance to change at schools according to ınspectors’ perspectives

Bu araştırma, ilköğretim okullarında görev yapan öğretmenlerin okullarda değişime karşı direniş nedenlerini eğitim denetmenlerinin görüşlerine göre saptamayı amaçlamaktadır. Araştırma, tarama modelinde betimsel bir çalışmadır. Araştırmanın çalışma grubunu 2009-2010 eğitim-öğretim yılında Türkiye Eğitim Müfettişleri Sendikasına üye 172 eğitim denetmeni oluşturmaktadır. Araştırmada veriler, “Değişime Karşı Direnme Ölçeği” ile toplanmıştır. Araştırma bulgularına göre, öğretmenlerin değişime karşı direnişleri daha çok değişim süreci konusundaki bilgi eksikliklerinden, yeni görev, rol ve sorumluluklar alma isteksizliklerinden, okulun kapasite eksikliğinden ve okul yöneticilerinin değişimi yönetememesinden kaynaklanmaktadır. Bununla birlikte öğretmenlerin değişimden zarar görme korkusu nedeniyle değişime orta düzeyde direnç gösterdikleri belirlenmiştir.This study aims to determine reasons and levels of primary school teachers’ resistance to change at schools according to inspectors’ perspectives. The sample of this descriptive study conducted in the 2009-2010 academic year consisted of 172 inspectors who are Union of All Inspectors (TEMSEN) members. The findings showed that teachers’ lack of knowledge of the change process and their reluctance to own new duties, roles, and responsibilities, lack of school capacity, school administrators’ ineffectiveness in management of change, and fear of being hurt by change are all under reasons of teachers’ resistance to change. Also, teachers’ level of resistance to change due to fear of being hurt by change is “medium” while due to other reasons, it is “high”

Analytical calculation of the electromagnetic field in SRM using conformal mapping method

Switched reluctance machine (SRM) has attracted more attention recently for its simple structure and high reliability. In this paper, an analytical method for solving the magnetic field in SRM is illustrated utilizing the Schwarz-Christoffel conformal mapping method. With the help of Matlab SC tools, a general radial flux SRM with linear material characteristic is analyzed. The flux density distribution along a contour in the airgap is obtained and torque is calculated using Maxwell stress tensor and compared with finite element method results. The comparisons show a good agreement and reveal the advantage of conformal mapping in time saving

Reasons and levels of teachers’ resistance to change at schools according to ınspectors’ perspectives

Bu araştırma, ilköğretim okullarında görev yapan öğretmenlerin okullarda değişime karşı direniş nedenlerini eğitim denetmenlerinin görüşlerine göre saptamayı amaçlamaktadır. Araştırma, tarama modelinde betimsel bir çalışmadır. Araştırmanın çalışma grubunu 2009-2010 eğitim-öğretim yılında Türkiye Eğitim Müfettişleri Sendikasına üye 172 eğitim denetmeni oluşturmaktadır. Araştırmada veriler, “Değişime Karşı Direnme Ölçeği” ile toplanmıştır. Araştırma bulgularına göre, öğretmenlerin değişime karşı direnişleri daha çok değişim süreci konusundaki bilgi eksikliklerinden, yeni görev, rol ve sorumluluklar alma isteksizliklerinden, okulun kapasite eksikliğinden ve okul yöneticilerinin değişimi yönetememesinden kaynaklanmaktadır. Bununla birlikte öğretmenlerin değişimden zarar görme korkusu nedeniyle değişime orta düzeyde direnç gösterdikleri belirlenmiştir.This study aims to determine reasons and levels of primary school teachers’ resistance to change at schools according to inspectors’ perspectives. The sample of this descriptive study conducted in the 2009-2010 academic year consisted of 172 inspectors who are Union of All Inspectors (TEMSEN) members. The findings showed that teachers’ lack of knowledge of the change process and their reluctance to own new duties, roles, and responsibilities, lack of school capacity, school administrators’ ineffectiveness in management of change, and fear of being hurt by change are all under reasons of teachers’ resistance to change. Also, teachers’ level of resistance to change due to fear of being hurt by change is “medium” while due to other reasons, it is “high”

The Effect of Neuronal Nitric Oxide Synthase Inhibitor 7-Nitroindazole on the Cell Death Induced by Zinc Administration in the Brain of Rats

BOSTANCI, Mehmet Omer/0000-0002-2887-1073WOS: 000265263900007Aim: To evaluate the effect of the neuronal nitric oxide synthase (nNOS) inhibitor 7-nitroindazole (7-Nl) on hippocampal cell loss induced by zinc hemisulfate salt (ZnSO4-7H2O) treatment. Materials and Methods: Rats were divided into 3 groups (n = 21; 7 rats in each group): Control, Zinc, and Zinc+7-NI. In the Zinc and Zinc+7-NI (pretreatment) groups, ZnSO4-7H2O was applied intracortically to the left sensory motor cortex. The 7-Nl (50 mg/kg) was injected into the third group (Zinc+7-NI) intraperitoneally 20 min prior to zinc application and daily for the next 7 days. Cell loss in the left and right hippocampal hemispheres was quantified by optical fractionator. which is a relatively unbiased and reliable stereological counting method. Results: Zinc produced decreases of 43.5% and 46.1 % in the number of viable neurons in the left and right hippocampal hemispheres, respectively, in comparison with control values. In the Zinc+7-NI group, cell losses were 16.2% and 18.5% in the left and right hemispheres. respectively, in the same conditions. Thus, 7-Nl exerted a significant neuroprotective effect against zinc-induced cell loss in the rat hippocampus (P < 0.05). Conclusions: These results suggest that nitric oxide contributes to the hippocampal cell loss induced by zinc sulfate and that the prevention of nitric oxide formation by nNOS blockade can reduce this cell loss

Extended field reconstruction method for modeling of interior permanent magnet synchronous machines

This paper presents an extended field reconstruction method (EFRM) that is developed to model an interior permanent magnet synchronous machine (IPMSM), which is known for its high power density and power factor. Traditional field reconstruction method is a very convenient tool for the modeling and analysis of the performance of the surface mounted permanent magnet machine (SPMSM). Regarding IPMSM, which usually works under saturation, traditional FRM method cannot be directly applied. An improved FRM, which considers both saturation and slottings effects, is proposed in this study. Comparisons with finite element analysis (FEA) show that EFRM has an acceptable accuracy and takes less computation time