10,691 research outputs found
Radio Emission from GRO J1655-40 during the 1994 Jet Ejection Episodes
We report multifrequency radio observations of GRO J1655-40 obtained with the
Australia Telescope Compact Array, the Molonglo Observatory Synthesis Telescope
and the Hartebeesthoek Radio Astronomy Observatory at the time of the major
hard X-ray and radio outbursts in 1994 August-September. The radio emission
reached levels of the order of a few Jy and was found to be linearly polarized
by up to 10%, indicating a synchrotron origin. The light curves are in good
agreement with those measured with the VLA, but our closer time sampling has
revealed two new short-lived events and significant deviations from a simple
exponential decay. The polarization data show that the magnetic field is well
ordered and aligned at right angles to the radio jets for most of the
monitoring period. The time evolution of the polarization cannot be explained
solely in terms of a simple synchrotron bubble model, and we invoke a hybrid
`core-lobe' model with a core which contributes both synchrotron and free-free
emission and `lobes' which are classical synchrotron emitters.Comment: 36 pages, 5 tables, 9 figures; accepted for publication in Ap
Lack of Mutual Respect in Relationship The Endangered Partner
Violence in a relationship and in a family setting has been
an issue of concern to various interest groups and professional organizations.
Of particular interest in this article is violence against women
in a relationship. While there is an abundance of knowledge on violence
against women in general, intimate or partner femicide seems to have
received less attention. Unfortunately, the incidence of violence against
women, and intimate femicide in particular, has been an issue of concern
in the African setting.
This article examines the trends of intimate femicide in an African setting
in general, and in Botswana in particular. The increase in intimate
femicide is an issue of concern, which calls for collective effort to address.
This article also examines trends offemicide in Botswana, and the
antecedents and the precipitating factors. Some studies have implicated
societal and cultural dynamics as playing significant roles in intimate
femicide in the African setting. It is believed that the patriarchal nature
of most African settings and the ideology of male supremacy have relegated
women to a subordinate role. Consequently, respect for women
in any relationship with men is lopsided in favor of men and has led to
abuse of women, including intimate femicide. Other militating factors in
intimate femicide ,are examined and the implications for counseling to
assist the endangered female partner are discussed
SUMSS: A Wide-Field Radio Imaging Survey of the Southern Sky. I. Science goals, survey design and instrumentation
The Molonglo Observatory Synthesis Telescope, operating at 843 MHz with a 5
square degree field of view, is carrying out a radio imaging survey of the sky
south of declination -30 deg. This survey (the Sydney University Molonglo Sky
Survey, or SUMSS) produces images with a resolution of 43" x 43" cosec(Dec.)
and an rms noise level of about 1 mJy/beam. SUMSS is therefore similar in
sensitivity and resolution to the northern NRAO VLA Sky Survey (NVSS; Condon et
al. 1998). The survey is progressing at a rate of about 1000 square degrees per
year, yielding individual and statistical data for many thousands of weak radio
sources. This paper describes the main characteristics of the survey, and
presents sample images from the first year of observation.Comment: 27 pages, 12 figures (figures 2, 8, 10 in jpg format); AJ, in pres
Universality and quantum effects in one-component critical fluids
Non-universal scale transformations of the physical fields are extended to
pure quantum fluids and used to calculate susceptibility, specific heat and the
order parameter along the critical isochore of He3 near its liquid-vapor
critical point. Within the so-called preasymptotic domain, where the Wegner
expansion restricted to the first term of confluent corrections to scaling is
expected valid, the results show agreement with the experimental measurements
and recent predictions, either based on the minimal-substraction
renormalization and the massive renormalization schemes within the
-model, or based on the crossover parametric equation of
state for Ising-like systems
Population, sexual and reproductive health, rights and sustainable development: forging a common agenda.
This article suggests that sexual and reproductive health and rights activists seeking to influence the post-2015 international development paradigm must work with sustainable development advocates concerned with a range of issues, including climate change, environmental issues, and food and water security, and that a way of building bridges with these communities is to demonstrate how sexual and reproductive health and rights are relevant for these issues. An understanding of population dynamics, including urbanization and migration, as well as population growth, can help to clarify these links. This article therefore suggests that whether or not sexual and reproductive health and rights activists can overcome resistance to discussing "population", become more knowledgeable about other sustainable development issues, and work with others in those fields to advance the global sustainable development agenda are crucial questions for the coming months. The article also contends that it is possible to care about population dynamics (including ageing and problems faced by countries with a high proportion of young people) and care about human rights at the same time. It expresses concern that, if sexual and reproductive health and rights advocates do not participate in the population dynamics discourse, the field will be left free for those for whom respecting and protecting rights may be less of a priority
Synthesis of 2-BMIDA 6,5-bicyclic heterocycles by Cu(I)/Pd(0)/Cu(II) cascade catalysis of 2-iodoaniline/phenols
A one-pot cascade reaction for the synthesis of 2-BMIDA 6,5-bicyclic heterocycles has been developed using Cu(I)/Pd(0)/Cu(II) catalysis. 2-Iodoanilines and phenols undergo a Cu(I)/Pd(0)-catalyzed Sonogashira reaction with ethynyl BMIDA followed by in situ Cu(II)-catalyzed 5-endo-dig cyclization to generate heterocyclic scaffolds with a BMIDA functional group in the 2-position. The method provides efficient access to borylated indoles, benzofurans, and aza-derivatives, which can be difficult to access through alternative methods
X-ray states and radio emission in the black hole candidate XTE J1550-564
We report on radio and X-ray observations of the black hole candidate (BHC)
XTE J1550-564 performed during its 2000 X-ray outburst. Observations have been
conducted with the Australia Telescope Compact Array (ATCA) and have allowed us
to sample the radio behavior of XTE J1550-564 in the X-ray Low Hard and
Intermediate/Very High states. We observed optically thin radio emission from
XTE J1550-564 five days after a transition to an Intermediate/Very High state,
but we observed no radio emission six days later, while XTE J1550-564 was still
in the Intermediate/Very High state. In the Low Hard state, XTE J1550-564 is
detected with an inverted radio spectrum. The radio emission in the Low Hard
state most likely originates from a compact jet; optical observations suggest
that the synchrotron emission from this jet may extend up to the optical range.
The total power of the compact jet might therefore be a significant fraction of
the total luminosity of the system. We suggest that the optically thin
synchrotron radio emission detected five days after the transition to the
Intermediate/Very High state is due to a discrete ejection of relativistic
plasma during the state transition. Subsequent to the decay of the optically
thin radio emission associated with the state transition, it seems that in the
Intermediate/Very High state the radio emission is quenched by a factor greater
than 50, implying a suppression of the outflow. We discuss the properties of
radio emission in the X-ray states of BHCs.Comment: 15 pages, including 3 figures. Accepted for publication in ApJ,
scheduled for the vol. 553 Jun 1, 2001 issu
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