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Effects of solar wind magnetosphere coupling recorded at different geomagnetic latitudes: Separation of directly-driven and storage/release systems
The effect on geomagnetic activity of solar wind speed, compared with that of the strength of the interplanetary magnetic field, differs with geomagnetic latitude. In this study we construct a new index based on monthly standard deviations in the H-component of the geomagnetic field for all geomagnetic latitudes. We demonstrate that for this index the response at auroral regions correlates best with interplanetary coupling functions which include the solar wind speed while mid- and low-latitude regions respond to variations in the interplanetary magnetic field strength. These results are used to isolate the responsible geomagnetic current systems
Probe for the strong parity violation effects at RHIC with three particle correlations
In non-central relativistic heavy ion collisions, \P-odd domains, which might
be created in the process of the collision, are predicted to lead to charge
separation along the system orbital momentum \cite{Kharzeev:2004ey}. An
observable, \P-even, but directly sensitive to the charge separation effect,
has been proposed in \cite{Voloshin:2004vk} and is based on 3-particle mixed
harmonics azimuthal correlations. We report the STAR measurements using this
observable for Au+Au and Cu+Cu collisions at =200 and 62 GeV.
The results are reported as function of collision centrality, particle
separation in rapidity, and particle transverse momentum. Effects that are not
related to parity violation but might contribute to the signal are discussed.Comment: 4 pages, Quark Matter 2008 Poster proceeding
The elements of a computational infrastructure for social simulation
Applications of simulation modelling in social science domains are varied and increasingly widespread. The effective deployment of simulation models depends on access to diverse datasets, the use of analysis capabilities, the ability to visualize model outcomes and to capture, share and re-use simulations as evidence in research and policy-making. We describe three applications of e-social science that promote social simulation modelling, data management and visualization. An example is outlined in which the three components are brought together in a transport planning context. We discuss opportunities and benefits for the combination of these and other components into an e-infrastructure for social simulation and review recent progress towards the establishment of such an infrastructure
Thermoacoustic tomography with variable sound speed
We study the mathematical model of thermoacoustic tomography in media with a
variable speed for a fixed time interval, greater than the diameter of the
domain. In case of measurements on the whole boundary, we give an explicit
solution in terms of a Neumann series expansion. We give necessary and
sufficient conditions for uniqueness and stability when the measurements are
taken on a part of the boundary
Origin, variability and age of biomass burning plumes intercepted during BORTAS-B
We use the GEOS-Chem atmospheric chemistry transport model to
interpret aircraft measurements of carbon monoxide (CO) in biomass
burning outflow taken during the 2011 BORTAS-B campaign over eastern
Canada. The model has some skill reproducing the observed
variability (<i>r</i> = 0.45) but has a negative bias for observations
below 100 ppb and a positive bias above 300 ppb. We
find that observed CO variations are largely due to NW North
American biomass burning, as expected, with smaller and less
variable contributions from fossil fuel combustion from eastern Asia
and NE North America. To help interpret observed variations of CO we
develop an Eulerian effective age of emissions (<i><span style="text-decoration:overline">A</span></i>)
metric, accounting for mixing and chemical decay, which we apply to
pyrogenic emissions of CO. We find that during BORTAS-B the age of
emissions intercepted over Halifax, Nova Scotia is typically 4–11
days, and on occasion as young as two days. We show that
<i><span style="text-decoration:overline">A</span></i> is typically 1–5 days older than the associated
photochemical ages inferred from colocated measurements of different
hydrocarbons. We find that the median difference between the age
measures (Δτ) in plumes (CH<sub>3</sub>CN > 150 ppt)
peaks at 3–5 days corresponding to a chemical retardation of
50%. We find a strong relationship in plumes between
<i><span style="text-decoration:overline">A</span></i> and Δτ (<i>r</i><sup>2</sup> = 0.60), which is not evident
outwith these plumes (<i>r</i><sup>2</sup> = 0.23). We argue that these observed
relationships, together with a robust observed relationship between
CO and black carbon aerosol during BORTAS-B (<i>r</i><sup>2</sup> > 0.7), form the
basis of indirect evidence that aerosols co-emitted with gases
during pyrolysis markedly slowed down the plume photochemistry
during BORTAS-B with respect to photochemistry at the same latitude
and altitude in clear skies
'She's like a daughter to me': insights into care, work and kinship from rural Russia
This article draws on ethnographic research into a state-funded homecare service in rural Russia. The article discusses intersections between care, work and kinship in the relationships between homecare workers and their elderly wards and explores the ways in which references to kinship, as a means of authenticating paid care and explaining its emotional content, reinforce public and private oppositions while doing little to relieve the tensions and conflicts of care work. The discussion brings together detailed empirical insights into local ideologies and practices as a way of generating new theoretical perspectives, which will be of relevance beyond the particular context of study
Charged anisotropic matter with linear equation of state
We consider the general situation of a compact relativistic body with
anisotropic pressures in the presence of the electromagnetic field. The
equation of state for the matter distribution is linear and may be applied to
strange stars with quark matter. Three classes of new exact solutions are found
to the Einstein-Maxwell system. This is achieved by specifying a particular
form for one of the gravitational potentials and the electric field intensity.
We can regain anisotropic and isotropic models from our general class of
solution. A physical analysis indicates that the charged solutions describe
realistic compact spheres with anisotropic matter distribution. The equation of
state is consistent with dark energy stars and charged quark matter
distributions. The masses and central densities correspond to realistic stellar
objects in the general case when anisotropy and charge are present.Comment: 17 pages, To appear in Class. Quantum Gra
Strangelets: Who is Looking, and How?
It has been over 30 years since the first suggestion that the true ground
state of cold hadronic matter might be not nuclear matter but rather strange
quark matter (SQM). Ever since, searches for stable SQM have been proceeding in
various forms and have observed a handful of interesting events but have
neither been able to find compelling evidence for stable strangelets nor to
rule out their existence. I will survey the current status and near future of
such searches with particular emphasis on the idea of SQM from strange star
collisions as part of the cosmic ray flux.Comment: Talk given at International Conference on Strangeness in Quark
Matter, 2006. 8 pages. 1 figur
Uniqueness of reconstruction and an inversion procedure for thermoacoustic and photoacoustic tomography
The paper contains a simple approach to reconstruction in Thermoacoustic and
Photoacoustic Tomography. The technique works for any geometry of point
detectors placement and for variable sound speed satisfying a non-trapping
condition. A uniqueness of reconstruction result is also obtained
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