1,218 research outputs found
Open String on Symmetric Product
We develop some basic properties of the open string on the symmetric product
which is supposed to describe the open string field theory in discrete
lightcone quantization (DLCQ). After preparing the consistency conditions of
the twisted boundary conditions for Annulus/M\"obius/Klein Bottle amplitudes in
generic non-abelian orbifold, we classify the most general solutions of the
constraints when the discrete group is . We calculate the corresponding
orbifold amplitudes from two viewpoints -- from the boundary state formalism
and from the trace over the open string Hilbert space. It is shown that the
topology of the world sheet for the short string and that of the long string in
general do not coincide. For example the annulus sector for the short string
contains all the sectors (torus, annulus, Klein bottle, M\"obius strip) of the
long strings. The boundary/cross-cap states of the short strings are classified
into three categories in terms of the long string, the ordinary boundary and
the cross-cap states, and the ``joint'' state which describes the connection of
two short strings. We show that the sum of the all possible boundary conditions
is equal to the exponential of the sum of the irreducible amplitude -- one body
amplitude of long open (closed) strings. This is typical structure of DLCQ
partition function. We examined that the tadpole cancellation condition in our
language and derived the well-known gauge group .Comment: 56 pages, 11 figures, Late
Clinical, hemodynamic, echocardiographic, angiographic profiles and post-operative outcomes among DCRV patients from a tertiary care referral center in India
Background: This retrospective study of data from 2006 to 2018 at a tertiary care referral center in India aims to document the contemporary clinical and hemodynamic profile of patients who were diagnosed with double chamber right ventricle (DCRV) based on echocardiography and cardiac catheterization. Patients were followed up and their outcomes were studied to document their short and long term outcomes.Methods: It is a retrospective observational study of patients diagnosed with DCRV in a tertiary care hospital in India. The diagnosis of DCRV was based on the following criteria: an echocardiographic diagnosis of DCRV with doppler evidence of a mid ventricular gradient; cardiac catheterization revealing a systolic pressure gradient between right ventricular inflow and outflow tracts; a right ventricular angiogram demonstrating an anomalous muscle bundle causing obstruction well below the infundibulum. All the patients were followed up for their long term outcomes.Results: All the patients underwent echocardiography and cardiac catheterization for confirmation of the diagnosis. Sixty percent of our patients presented during adulthood, which is very unusual presentation of this disease entity. Median age of our patient cohort was 23.5 years. Patients presenting during adulthood have atypical symptoms. Dyspnea was the most common presenting symptom in this study. Right ventricular hypertrophy (73.3%)and right bundle branch pattern (26.6%) were the common electrocardiographic findings in our patients. DCRV is commonly associated with other anomalies. Ventricular septal defect (VSD) was the commonest associated anomaly, which was seen in 80% of our patients. Mean gradient cross the anomalous muscle bundle was 67.5 mmHg. Three of our patients (20%) had no associated anomaly, which is very rare in DCRV. Eight patients underwent surgical correction with significant reduction in gradients in all and no perioperative mortality. Median follow up of 8 years showed no adverse outcomes and no progression of gradients.Conclusions: This study describes in detail the clinical profile, echocardiographic and angiographic identification of anomalous muscle bundles in DCRV patients, which will help the young readers in identifying this often missed diagnosis. It highlights the unusual presentation during adulthood with atypical symptoms in DCRV patients with excellent long-term outcomes on follow up
Lateral location of placenta on ultrasound as a predictive test for preeclampsia
Background: Hypertensive disorders represent the most common medical complication of pregnancy Pre-eclampsia complicates approximately 2-7% of pregnancies and is a major cause of maternal and perinatal morbidity This has led to the interest in screening. The placenta is located laterally in majority of patients with abnormal flow velocity waveforms. In the light of these observations, we designed a prospective study to find out whether the lateral location of placenta as seen by ultrasound at II and III trimester of gestation can be used to predict the development of preeclampsia.Methods: A prospective observational study was done in PESIMSR, Kuppam, Andhra Pradesh. The aim of the study was to find out whether placental laterality as determined by ultrasound can be used as a predictor of development of gestational hypertension, development of preeclampsia/eclampsia During the study period of November 2013 to November 2014, all antenatal women attending the OPD in II and III trimester without any medical disorders likeDM, HTN, renal disease, cardiac disease or smoking, who undergo ultrasound in II and III trimester were included. The location of the placenta was determined by real time ultrasound in II and III trimester. The placenta will be classified as central when it is equally distributed between the right and the left side of the uterus irrespective of anterior, posterior or fundal position. When 75% or more of the placental mass is to one side of the midline, it is classified as unilateral right or left placenta. subjects were followed upto delivery for development of gestational hypertension/ preeclampsia/eclampsia as per the ACOG criteria.Results: 66% patients in the lateral placenta group developed preeclampsia. Only 36%in the central group developed preeclampsia. The association of lateral placenta as a predictor of preeclampsia had a P value of <0.001 which is statistically significant. Incidence of preclampsia is more in primigravidas compared to multigravidas. Most of the pre eclamptics had their onset at 29 â 32 weeks of gestation.Conclusions: The study shows that placental position determined by ultrasonogram in II and III trimester of gestation is an excellent screening tool for the prediction of pre-eclampsia. The test is ideal because it is simple, non-invasive, cost effective and convenient to the women
Fast Neutron Response Of A -loaded Liquid Scintillator
oS(FNDA2006)046 © Copyright owned by the author(s) under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike Licence
Effective potential analysis for 5D SU(2) gauge theories at finite temperature and radius
We calculate the one loop effective potential for a 5D SU(2) gauge field
theory at finite temperature and radius R=1/M. This calculation is
performed, for the first time, in the case of background fields with two
constant components (directed towards the compact extra dimension
with radius R) and (directed towards the compact Euclidean time
with radius ). This model possesses two discrete symmetries known as
Z_{M}(2) and Z_{T}(2). The corresponding phase diagram is presented in Ref. 4.
However the arguments which lead to this diagram are mainly qualitative. We
present a detailed analysis, from our point of view, for this phase diagram,
and we support our arguments performing lattice simulations for a simple
phenomenological model with two scalar fields interacting through the
previously calculated potential.Comment: 18 pages, 7 figures ; typos correcte
Gauge theories of spacetime symmetries
Gauge theories of conformal spacetime symmetries are presented which merge
features of Yang-Mills theory and general relativity in a new way. The models
are local but nonpolynomial in the gauge fields, with a nonpolynomial structure
that can be elegantly written in terms of a metric (or vielbein) composed of
the gauge fields. General relativity itself emerges from the construction as a
gauge theory of spacetime translations. The role of the models within a general
classification of consistent interactions of gauge fields is discussed as well.Comment: 8 pages, revtex; v2: minor improvements of text and formulas; v3:
typo in formula after eq. (35) correcte
Mixing of dust aerosols into a mesoscale convective system: Generation, filtering and possible feedbacks on ice anvils
International audienceDuring the second Specific Observing Period (SOP) of the African Monsoon Multidisplinary Analyses (AMMA) campaign, several intense mesoscale convective systems (MCS) developed over Niger. An examination of a particular convective storm simulated with a mesoscale model near Banizoumbou, Niger, on 1 July, 2006, shows that this MCS generates a strong emission of dust particles at the leading edge of its density current. A fraction of these dust aerosols are uplifted by the convective core of the system and redistributed by aqueous processes. Aerosol impaction scavenging is the main process by which particles are deposited within the mesoscale convective system. However, small particles (smaller than 1 ÎŒm) that are not efficiently scavenged, are able to reach the upper troposphere at a concentration of 6 particles per cm3. This suggests that deep convection over semi-arid regions is able to create its own ice nuclei in high concentrations. This leads to the question: can deep convection over semi-arid regions affect particular ice properties such as ice anvil extension or induce possible feedbacks of dust on precipitation through ice sedimentation
A Novel Mechanism of B Cell-Mediated Immune Suppression through CD73 Expression and Adenosine Production
Immune suppression by regulatory T cells and regulatory B cells is a critical mechanism to limit excess inflammation and autoimmunity. IL-10 is considered the major mediator of B cell induced immune suppression. We report a novel mechanism for immune suppression through adenosine generation by B cells. We identified a novel population of B cells that expresses CD73 as well as CD39, two ectoenzymes that together catalyze the extracellular dephosphorylation of adenine nucleotides to adenosine. Whereas CD39 expression is common among B cells, CD73 expression is not. Approximately 30-50% of B-1 cells (B220(+)CD23(-)) and IL-10 producing B (B10) cells (B220(+)CD5(+)CD1d(hi)) are CD73111, depending on mouse strain, whereas few conventional B-2 cells (B220+CD23+AA4.1) express CD73. In keeping with expression of both CD73 and CD39, we found that CD73(+) B cells produce adenosine in the presence of substrate, whereas B-2 cells do not. CD73(-/-) mice were more susceptible to dextran sulfate sodium salt (DSS)-induced colitis than wild type (WT) mice were, and transfer of CD73+ B cells ameliorated the severity of colitis, suggesting that B cell CD73/CD39/adenosine can modulate DSS-induced colitis. IL-10 production by B cells is not affected by CD73 deficiency. Interestingly, adenosine generation by IL-10(-/-) B cells is impaired because of reduced expression of CD73, indicating an unexpected connection between IL-10 and adenosine and suggesting caution in interpreting the results of studies with IL-10(-/-) cells. Our findings demonstrate a novel regulatory role of B cells on colitis through adenosine generation in an IL10 independent manner
Thermal history of the string universe
Thermal history of the string universe based on the Brandenberger and Vafa's
scenario is examined. The analysis thereby provides a theoretical foundation of
the string universe scenario. Especially the picture of the initial oscillating
phase is shown to be natural from the thermodynamical point of view. A new tool
is employed to evaluate the multi state density of the string gas. This
analysis points out that the well-known functional form of the multi state
density is not applicable for the important region , and derives a
correct form of it.Comment: 39 pages, no figures, use revtex.sty, aps.sty, aps10.sty &
preprint.st
On a possible new R^2 theory of supergravity
We consider a new MacDowell-Mansouri R^2-type of supergravity theory, an
extension of conformal supergravity, based on the superalgebra Osp(1|8).
Invariance under local symmetries with negative Weyl weight is achieved by
imposing chirality-duality and double-duality constraints on curvatures, along
with the usual constraint of vanishing supertorsion. An analysis of the
remaining gauge symmetries shows that those with vanishing Weyl weight are
invariances of the action at the linearized level. For the symmetries with
positive Weyl weight we find that invariance of the action would require
further modifications of the transformation rules. This conclusion is supported
by a kinematical analysis of the closure of the gauge algebra.Comment: 52 pages, Late
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