7,795 research outputs found
The spectral shift function and spectral flow
This paper extends Krein's spectral shift function theory to the setting of
semifinite spectral triples. We define the spectral shift function under these
hypotheses via Birman-Solomyak spectral averaging formula and show that it
computes spectral flow.Comment: 47 page
Megakaryoblastic Termination of Myeloproliferative Disorders
Megakaryoblastic termination of myeloproliferative disorders is rare. The morphology of megakaryoblastic transformation can be subtle and is often mistaken for myeloid or lymphoid proliferations. Previously reported observations suggest a relatively poor prognosis for this category of patients, making precise diagnosis imperative. A multifaceted approach using morphology, ultrastructure, cytochemistry, and immunological membrane analysis may be helpful. We present two cases of myeloproliferative disorder with aggressive megakaryoblastic phases (myelofibrosis with agnogenic myeloid metaplasia and chronic myeloid leukemia with blast crisis). The clinical course is described and the results of the morphological, cytochemical, ultrastructural, and cytogenetic studies of both cases are presented. In addition, immunochemical studies (flow cytometry) and platelet function studies (aggregation, heta-thromboglobulin, and platelet factor IV release) were done for one of these patients
Randomized community-level HIV prevention intervention trial for men who drink in South African alcohol-serving venues
South African alcohol-serving establishments (i.e., shebeens) offer unique opportunities to reduce HIV risks among men who drink. Purpose: To test an individual- and a social structural-level HIV prevention intervention for men who drink in shebeens. Methods: Twelve matched pairs of township neighbourhoods were randomized to receive either (i) an HIV prevention intervention (guided by Social Action Theory) to reduce sexual risk and increase risk reduction communication in social networks, or (ii) an attention-matched control intervention that focused on the prevention of relationship violence. At the individual level, the interventions delivered skills building workshops focused on sexual risk reduction. At the social structural level, the intervention aimed to increase conversations about safer sex among men in the shebeens, distributed small media and implemented community educational events. Individual-level outcomes were assessed by following the workshop cohorts for 1 year (N = 984), and community-level outcomes were examined through cross-sectional community surveys conducted for 1 year in the shebeens (N = 9,678). Results: Men in the HIV prevention workshops demonstrated greater condom use, more HIV prevention-oriented conversations and greater perceptions of safer sex norms than men in the comparison workshops. Changes at the community level demonstrated significant differences in condom use, although the pattern was not consistent over time. Conclusions: Multi-level interventions that target men who drink in South African shebeens may help reduce risks for HIV and other sexually transmitted infections.Web of Scienc
Fast simulation of a quantum phase transition in an ion-trap realisable unitary map
We demonstrate a method of exploring the quantum critical point of the Ising
universality class using unitary maps that have recently been demonstrated in
ion trap quantum gates. We reverse the idea with which Feynman conceived
quantum computing, and ask whether a realisable simulation corresponds to a
physical system. We proceed to show that a specific simulation (a unitary map)
is physically equivalent to a Hamiltonian that belongs to the same universality
class as the transverse Ising Hamiltonian. We present experimental signatures,
and numerical simulation for these in the six-qubit case.Comment: 12 pages, 6 figure
Early phase of massive star formation: A case study of Infrared dark cloud G084.81-01.09
We mapped the MSX dark cloud G084.81-01.09 in the NH3 (1,1) - (4,4) lines and
in the J = 1-0 transitions of 12CO, 13CO, C18O and HCO+ in order to study the
physical properties of infrared dark clouds, and to better understand the
initial conditions for massive star formation. Six ammonia cores are identified
with masses ranging from 60 to 250 M_sun, a kinetic temperature of 12 K, and a
molecular hydrogen number density n(H2) ~ 10^5 cm^-3. In our high mass cores,
the ammonia line width of 1 km/s is larger than those found in lower mass cores
but narrower than the more evolved massive ones. We detected self-reversed
profiles in HCO+ across the northern part of our cloud and velocity gradients
in different molecules. These indicate an expanding motion in the outer layer
and more complex motions of the clumps more inside our cloud. We also discuss
the millimeter wave continuum from the dust. These properties indicate that our
cloud is a potential site of massive star formation but is still in a very
early evolutionary stage
Investigation of two-solvent grinding-assisted liquid phase exfoliation of layered MoS2
Grinding-assisted sonication exfoliation of stratified materials such as MoS2 is a widely used method for the preparation of their single- and few-layer thick flakes. This work introduces a two-solvent step approach utilizing a separate solvent during the grinding phase, while implementing ethanol during exfoliation. It is found that the grinding solvent played a critical role, determining exfoliation yield, flake dimensions, and morphology, highlighting the importance of such parameters in the process. Furthermore, it is found that the commonly used N-methyl-2-pyrrolidone (NMP) leads to persistent residues on the exfoliated flakes, which may alter the properties of the flakes and interfere with the development of electronic devices and other applications. A solvent residue free exfoliation method is presented herein, which may be advantageous for future studies
First Space-based Microlens Parallax Measurement of an Isolated Star: Spitzer Observations of OGLE-2014-BLG-0939
We present the first space-based microlens parallax measurement of an
isolated star. From the striking differences in the lightcurve as seen from
Earth and from Spitzer (~1 AU to the West), we infer a projected velocity
v_helio,projected ~ 250 km/s, which strongly favors a lens in the Galactic Disk
with mass M=0.23 +- 0.07 M_sun and distance D_L=3.1 +- 0.4 kpc. An ensemble of
such measurements drawn from our ongoing program could be used to measure the
single-lens mass function including dark objects, and also is necessary for
measuring the Galactic distribution of planets since the ensemble reflects the
underlying Galactic distribution of microlenses. We study the application of
the many ideas to break the four-fold degeneracy first predicted by Refsdal 50
years ago. We find that this degeneracy is clearly broken, but by two
unanticipated mechanisms.Comment: 26 pages, 3 figures, submitted to Ap
How to remove the boundary in CFT - an operator algebraic procedure
The relation between two-dimensional conformal quantum field theories with
and without a timelike boundary is explored.Comment: 18 pages, 2 figures. v2: more precise title, reference correcte
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