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Chandra News
The Chandra Newsletter contains articles about the CXC and the Chandra mission. The Chandra Newsletter appears once a year and is edited by Paul J. Green, with editorial assistance and layout by Evan Tingle. We welcome contributions from readers. Comments on the newsletter, or corrections and additions to the hardcopy mailing list should be sent to: [email protected]
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A Tracing Method for Pricing Inter-Area Electricity Trades
In the context of liberalisation of electricity markets world wide, the need for agreed protocols for electricity trades between systems with different charges poses a special challenge. System operators need to know how much a given trade uses the network, in order to allocate an appropriate portion of their costs to that trade. This paper discusses a technique, tracing, for determining how much each of a number of trades uses different parts of the electricity network. The scheme is based on the assumption that at any network node, inflows are shared proportionally between outflows (and vice versa). The paper outlines the technique and shows how it could be applied to the problem of charging cross-border trades. The paper goes on to demonstrate that the technique has a game theoretic rationale, in that it produces the Shapley value solution to a game equivalent to this allocation problem
The Relationship Between the High Energy Continuum and Emission Lines in QSOs: A Low-Redshift Sample
Quasar emission lines are sensitive to both the luminosity and shape of the
quasars' high energy continuum - primarily in the soft X-ray and the (obscured)
extreme ultraviolet. We initiate the first large-scale, multi-line
investigation of correlations between the QSO soft X-ray continuum and UV line
emission, using an IUE/Einstein sample. We characterize the distributions of
line equivalent and velocity widths (EW and FWHM) of 85 QSOs in the IUE atlas
of Lanzetta et al. (1993), using a new error analysis for objective, automated
line measurements, and contrast measured line parameters to the QSO continuum
spectral energy distributions (SEDs). We find significant correlations between
EW and UV luminosity (e.g., the well-studied Baldwin effect) for Lya, CIV,
HeII, and CIII. EW(CIII) and EW(HeII) show previously unreported correlations
with Lx which for CIII appears to be primary. The line ratios CIII/Lya and
HeII/Lya both show strongest dependence on Lx. EW(Lya) correlates strongly with
spectral slopes \alpha_{uv} and \alpha_{ox}, but NOT with Lx. We argue that one
simple geometrical interpretation of the Baldwin effect (BEff) as a result of a
distribution of disk inclinations is not plausible. The BEff weakens or
disappears when line emission is correctly compared to the luminosity in the
continuum bandpass relevant to its production, which suggests that the BEff is
due to a change in SED with luminosity. Our prediction that no BEff relative to
X-ray luminosity should be found for FeII or MgII emission lines, will be
tested in a later paper, extended to a wider redshift/luminosity range.Comment: 31 pages including 3 figures, AAS latex, plus 6 tables totaling 8
pages, to appear in ApJ Vol. 468, September 1, 199
Deactivation of gold(I) catalysts in the presence of thiols and amines – characterisation and catalysis
Probability for Primordial Black Holes in Higher Derivative Theories
The probability for quantum creation of an inflationary universe with a pair
of black holes in higher derivative theories has been studied. Considering a
gravitational action which includes quadratic () and/or cubic
term () in scalar curvature in addition to a cosmological constant
() in semiclassical approximation with Hartle-Hawking boundary
condition, the probability has been evaluated. The action of the instanton
responsible for creating such a universe, with spatial section with
topology, is found to be less than that with a spatial
topology, unless in -theory. In the
theory, however, there exists a set of solutions without a cosmological
constant when and which admit
primordial black holes (PBH) pair in an inflationary universe scenario. We note
further that when , one gets PBH pairs in the two cases :
(i) with and both positive and (ii) with positive
and negative satisfying a constraint .
However, the relative probability for creation of an inflationary universe with
a pair of black holes in the -theory suppresses when or . However, if the above
constraints are relaxed one derives interesting results leading to a universe
with PBH in -theory without cosmological constant. PACS No(s). :
04.20.Jb, 04.60.+n, 98.80.HwComment: 15 pages, No figures. accepted in Int. J. Mod. Phys. D (2001
Rape and Posttraumatic Stress Disorder (PTSD): Examining the Mediating Role of Explicit Sex-Power Beliefs for Men Versus Women
Many rape survivors exhibit symptoms of post-traumatic stress disorder (PTSD), and recent literature suggests survivors\u27 beliefs about sex and control may affect PTSD symptoms. The present study examined beliefs about sex and power as potential mediators of the relationship between rape and PTSD symptoms for men versus women. Participants (N = 782) reported lifetime history of rape, current PTSD symptoms, and beliefs about sex and power. Women reported higher levels of lifetime history of rape than men (19.7% for women; 9.7% for men). While rape history predicted PTSD symptoms for both genders, beliefs about sex and power were shown to be a significant partial mediator of this relationship for men, but not for women. Results extend the literature on rape and PTSD by suggesting that survivors\u27 beliefs about sex and power are connected and can affect their PTSD symptoms. Additionally, results illustrate how sexual violence against men may reaffirm male gender roles that entail power and aggression, and ultimately affect trauma recovery
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