57 research outputs found
Follow up of GW170817 and its electromagnetic counterpart by Australian-led observing programmes
The discovery of the first electromagnetic counterpart to a gravitational wave signal has generated follow-up observations by over 50 facilities world-wide, ushering in the new era of multi-messenger astronomy. In this paper, we present follow-up observations of the gravitational wave event GW170817 and its electromagnetic counterpart SSS17a/DLT17ck (IAU label AT2017gfo) by 14 Australian telescopes and partner observatories as part of Australian-based and Australian-led research programs. We report early- to late-time multi-wavelength observations, including optical imaging and spectroscopy, mid-infrared imaging, radio imaging, and searches for fast radio bursts. Our optical spectra reveal that the transient source emission cooled from approximately 6 400 K to 2 100 K over a 7-d period and produced no significant optical emission lines. The spectral profiles, cooling rate, and photometric light curves are consistent with the expected outburst and subsequent processes of a binary neutron star merger. Star formation in the host galaxy probably ceased at least a Gyr ago, although there is evidence for a galaxy merger. Binary pulsars with short (100 Myr) decay times are therefore unlikely progenitors, but pulsars like PSR B1534+12 with its 2.7 Gyr coalescence time could produce such a merger. The displacement (~2.2 kpc) of the binary star system from the centre of the main galaxy is not unusual for stars in the host galaxy or stars originating in the merging galaxy, and therefore any constraints on the kick velocity imparted to the progenitor are poor
Cysteinyl-leukotriene receptor antagonism blunts the acute hypotensive response to endotoxin in cats
This study evaluated the effects of a cysteinyl-leukotriene-1 (cys-LT-1) receptor antagonist, zarfirlukast, during feline endotoxemia. Six adult, sexually intact male cats received either placebo or zarfirlukast (10 mg, PO) and endotoxin (2 ÎŒg/kg/h q 6 h) in a cross-over design. Rectal temperature, heart rate, systolic arterial blood pressure, plasma tumor necrosis factor (TNF) activity, interleukin (IL)-6 concentration and urine cys-LT to creatinine ratio were evaluated. The rectal temperature, plasma TNF activity and IL-6 concentrations were significantly higher and systolic arterial blood pressure and heart rate significantly lower after endotoxin infusion. Cats treated with zafirlukast had a significantly higher blood pressure at 4 h (P=0.002) compared to placebo. Urine cys-LT to creatinine ratio was significantly greater in the cats treated with zafirlukast compared to placebo (P=0.02). Zafirlukast administration ameliorated the acute hypotensive response to endotoxin in cats, but failed to significantly alter rectal temperature, heart rate or production of TNF and IL-6
Enterprise Modelling for an Educational Information Infrastructure
This paper reports the modelling exercise of an educational information infrastructure that aims to support the organisation of teaching and learning activities suitable for a wide range of didactic policies. The modelling trajectory focuses on capturing invariant structures of relations between entities in educational organisation into Enterprise object models. An Educational Model Space has been introduced to define the problem domain context for the modelling. In this space, educational requirements have been elaborated towards the Open Distributed Processing Enterprise Viewpoint object models expressed in terms of the Unified Modelling Language. Recursive structures, which are uniform for the planning, performance and evaluation activities of education, have been used to capture the dynamic needs of education
Cancer registration statistics Scotland 1991-1990
SIGLEAvailable from British Library Document Supply Centre- DSC:3046.4967(1981/1990) / BLDSC - British Library Document Supply CentreGBUnited Kingdo
Effects of gamma radiation on the sterility and behavioral quality of the caribbean fruit fly, Anastrepha suspensa (Loew) (Diptera:Tephritidae) Efeitos da radiação gama na esterilização e comportamento da mosca-do-caribe, Anastrepha suspensa (Low) (Diptera:Tephritidae)
Pupae of Anastrepha suspensa (Loew) were irradiated 2 days before adult eclosiĂłn in an air atmosphere with 15, 20, 25, 30, 50 and 70 Gy of gamma radiation (Co-60). The radiation effects on sterility and other parameters of quality and behavior of males and females of caribfly were established. Males became fully sterile with a dose of 50 Gy and females laid no eggs when exposed to 25 Gy. Radiation had no significant effect on adult eclosion, sex ratio, flight ability and irritability, but female mortality was affected significantly by radiation, showing higher survival rates in low dosage treatments. The mating behavior of the males was reduced significantly by increasing the radiation doses.<br>Pupas de Anastrepha suspensa (Loew) foram irradiadas dois dias antes da emergĂȘncia dos adultos em atmosfera de ar com as doses de 15, 20, 25, 30, 50 e 70 Gy de radiação gama (Co-60). Foram avaliados os efeitos da radiação sobre a esterilidade e outros parĂąmetros de qualidade e comportamento de machos e fĂȘmeas de mosca-do-caribe. Machos tornaram-se totalmente estĂ©reis com uma dose de 50 Gy e as fĂȘmeas nĂŁo ovipositaram quando expostas a 25 Gy. A radiação nĂŁo teve efeito significativo sobre a taxa de emergĂȘncia de adultos, na razĂŁo sexual, na habilidade de vĂŽo e na irritabilidade desses insetos. Somente a mortalidade das fĂȘmeas foi afetada significativamente pela radiação, causando unia maior sobrevivĂȘncia nas dosagens mais baixas. A atividade de acasalamento dos machos foi reduzida significativamente com o incremento da dosagem de radiação
Strain distribution in copper tensile specimens prestrained in rolling
Abstract Sequences of orthogonal rolling-tension experiments were performed on polycrystalline copper sheets. The effect of strain path change on subsequent yield and flow behavior has been investigated. Optical microscopy and transmission electron microscopy (TEM) were used to clarify the physical mechanisms occurring during the second deformation. The observed increase in yield stress in reloading was related to the change of slip systems corresponding to the glide of dislocations with a Burgers vector, which had not been active during prestrain. The transient observed in the workhardening behavior after the path change corresponds to the appearance of disorganization in the dislocation microstructure. It was shown that no special feature of slip behavior inside the grains can be related to the nonhomogeneous surface deformation observed at the beginning of reloading. Also, the plastic instability of prestrained samples corresponding to the maximum load in tension does not seem to be directly controlled by the developed local substructure. The nonuniform deformation observed in reloading was studied using a simplified macroscopic two-zone model. It takes into account the presence of geometrical defects in the samples and considers the importance of the mechanical behavior. The macroscopic results, concerning the delay of starting deformation in some regions, are explained by the model, which allows formulation of an analytical condition necessary for deformation to spread through the length of the sample before necking takes place
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