Strong Ultraviolet Pulse From a Newborn Type Ia Supernova

Type Ia supernovae are destructive explosions of carbon oxygen white dwarfs. Although they are used empirically to measure cosmological distances, the nature of their progenitors remains mysterious, One of the leading progenitor models, called the single degenerate channel, hypothesizes that a white dwarf accretes matter from a companion star and the resulting increase in its central pressure and temperature ignites thermonuclear explosion. Here we report observations of strong but declining ultraviolet emission from a Type Ia supernova within four days of its explosion. This emission is consistent with theoretical expectations of collision between material ejected by the supernova and a companion star, and therefore provides evidence that some Type Ia supernovae arise from the single degenerate channel.Comment: Accepted for publication on the 21 May 2015 issue of Natur

A Wolf-Rayet-like progenitor of SN 2013cu from spectral observations of a stellar wind.

The explosive fate of massive Wolf-Rayet stars (WRSs) is a key open question in stellar physics. An appealing option is that hydrogen-deficient WRSs are the progenitors of some hydrogen-poor supernova explosions of types IIb, Ib and Ic (ref. 2). A blue object, having luminosity and colours consistent with those of some WRSs, has recently been identified in pre-explosion images at the location of a supernova of type Ib (ref. 3), but has not yet been conclusively determined to have been the progenitor. Similar work has so far only resulted in non-detections. Comparison of early photometric observations of type Ic supernovae with theoretical models suggests that the progenitor stars had radii of less than 10(12) centimetres, as expected for some WRSs. The signature of WRSs, their emission line spectra, cannot be probed by such studies. Here we report the detection of strong emission lines in a spectrum of type IIb supernova 2013cu (iPTF13ast) obtained approximately 15.5 hours after explosion (by 'flash spectroscopy', which captures the effects of the supernova explosion shock breakout flash on material surrounding the progenitor star). We identify Wolf-Rayet-like wind signatures, suggesting a progenitor of the WN(h) subclass (those WRSs with winds dominated by helium and nitrogen, with traces of hydrogen). The extent of this dense wind may indicate increased mass loss from the progenitor shortly before its explosion, consistent with recent theoretical predictions

Energetic eruptions leading to a peculiar hydrogen-rich explosion of a massive star

Every supernova so far observed has been considered to be the terminal explosion of a star. Moreover, all supernovae with absorption lines in their spectra show those lines decreasing in velocity over time, as the ejecta expand and thin, revealing slower-moving material that was previously hidden. In addition, every supernova that exhibits the absorption lines of hydrogen has one main light-curve peak, or a plateau in luminosity, lasting approximately 100 days before declining1. Here we report observations of iPTF14hls, an event that has spectra identical to a hydrogen-rich core-collapse supernova, but characteristics that differ extensively from those of known supernovae. The light curve has at least five peaks and remains bright for more than 600 days; the absorption lines show little to no decrease in velocity; and the radius of the line-forming region is more than an order of magnitude bigger than the radius of the photosphere derived from the continuum emission. These characteristics are consistent with a shell of several tens of solar masses ejected by the progenitor star at supernova-level energies a few hundred days before a terminal explosion. Another possible eruption was recorded at the same position in 1954. Multiple energetic pre-supernova eruptions are expected to occur in stars of 95 to 130 solar masses, which experience the pulsational pair instability2,3,4,5. That model, however, does not account for the continued presence of hydrogen, or the energetics observed here. Another mechanism for the violent ejection of mass in massive stars may be required

Effect of genotype on growth traits of rabbits

Genotype effect on growth traits of rabbits were investigated in a randomised complete block design using one hundred and twenty - 10-week-old breeding rabbits. The breeds of rabbits used were New Zealand white, Dutch, chinchilla and were characterized using body weight (BW), heart girth (HG), shoulder to tail (ST), head to shoulder (HS), ear length (EL) tail length (TL), and height at withers (HW). The result reveals that daily feed intake, average daily weight gain and feed efficiency ratio were significantly (

Knowledge and risk factors for Hypertension among commercial transport workers in Lagos

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Haemorheological factors in diabetes mellitus patients in Obafemi Awolowo University Teaching Hospital Complex (OAUTHC), Ile-Ife, Nigeria

A study on haemorheological factors in diabetes mellitus patients was carried out. Fifty blood samples were analyzed, comprising of thirty (30) diagnosed diabetes mellitus patients attending chemical pathology Clinic in OAUTH Ile-Ife and twenty (20) from apparently health individuals. The haemorheological parameters determined in this study were Packed cell volume (PCV); Erythrocyte Sedimentation Rate (ESR), Plasma Fibrinogen Concentration (PFC), whole blood viscosity (WBV), Plasma Viscosity (PV), and plasma glucose. Microhaematocrit, the Westergren's and Ingram's (1961) methods were used respectively for analysis, while technique of Reid and Ugwu (1987) was used for whole blood and plasma viscosity. Glucose-oxidase method was used for plasma glucose estimation. The mean ± S.E.M values obtained for the patients are: PCV 39%, ESR 35mm Westergren in 1 hour, PFC 55.50g/m., WBV 6.12, PV 1.97 and glucose 7.39mmol/L while those of controls are: PCV 42.45%, ESR 6.80, PFC 31.60g/ml, WBV 3.84, PV 1.56 and glucose 3.94mmol/L. All the parameters were statistically significant (

Hematological profile of Plasmodium falciparum infected patients in Ile- Ife southwest, Nigeria

Hematological profile of Plasmodium falciparum infected patients in Ile- Ife, southwest Nigeria was analyzed across 60 blood samples. Forty of these samples were from confirmrd P. falciparum infected patients attending outpatient clinic at Obafemi Awolowo University Teaching Hospital Complex, Ile-Ife, while 20 were from apparently healthy individuals not infected with malaria parasites (control). Standard methods were used to determine the haematocrit, erythrocytes sedimentation rate (ESR), plasma and whole blood viscosity and fibrinogen concentration (clot weight). There were statistically significant differences between the mean ± SD of infected and control subjects in the haematocrit levels (32.58±8.10 and 42.90±7.76) respectively ERS (24.38±3.00 and 8.20±1.91) and plasma fibrinogen concentration (5.09±1.23 and 3.16±0.73) (p<0.05). The differences in the mean ± SD of whole blood viscosity (6.50±0.80 and 5.57±1.42) and mean of plasma viscosity for the control and infected subjects were not statistically significant (p>0.05). The above results showed that Plasmodium falciparum infected patients are at risk of thrombosis.Keywords: Plasmodium falciparum, blood, Hematological, malariaInternational Journal of Natural and Applied Sciences, 6(2): 236-238, 201