587 research outputs found
Epidemiology and the agreement rate of serological tests in human brucellosis in North East of Iran
Background: Brucellosis still remains a major health problem with different symptoms and various diagnostic methods. Diagnostic methods of brucellosis are usually based on detecting specific antibodies in the patient’s serum. Nowadays, many serological tests are applied for the diagnosis of human brucellosis. Most routine tests are serum agglutination tests based on Wright and 2-Mercaptoethanol (2-ME). Objectives: The aim of this study (cross sectional study) was to evaluate the prevalence of brucellosis and assess the degree of agreement among serum samples of suspected brucellosis serological tests routinely performed in Mashhad, Iran. Patients and Methods: This study was conducted in Mashhad from August 2011 to September 2012. Sera (2 - 3 mL) were collected from 83 cases suspected of brucellosis among 594 patients. Ten serum samples were collected from healthy subjects as control sera. Rose Bengal test for initial screening and Wright and 2 ME as standard tests were conducted to determine antibody titers. Thereafter, IgG and IgM levels were determined by the Enzyme Linked Immunosorbent Assay (ELISA) method. Results: Among 83 serum samples, Rose Bengal test was able to identify 20 (12%) positive specimens; the standard tube agglutination test was able to detect 30 (18%) positive samples, and the ELISA IgG and ELISA IgM were able to trace 42 (21%) and 13 (6.5%) positive samples, respectively. Ten control samples had negative results for the ELISA method. The results were calculated by the Kappa formula. The highest level of agreement was among 1 = KRB-SAT tests and the lowest level of agreement was among tests K ELISA IgM-IgG = 0.30. Conclusions: According to the results, brucellosis has remained endemic in this region. Most cases were detected by ELISA IgG. The highest kappa agreements were between tests KRB-SAT, KRB-IgG and KSAT-IgG, while the lowest levels of agreement were between tests SAT-IgM and ELISA IgM-IgG. Considering that ELISA IgM results are covered by SAT and ELISA IgG test results, applications of this test do not seem necessary. © 2015, Infectious Diseases and Tropical Medicine Research Center
Three Theorems on Near Horizon Extremal Vanishing Horizon Geometries
EVH black holes are Extremal black holes with Vanishing Horizon area, where
vanishing of horizon area is a result of having a vanishing one-cycle on the
horizon. We prove three theorems regarding near horizon geometry of EVH black
hole solutions to generic Einstein gravity theories in diverse dimensions.
These generic gravity theories are Einstein-Maxwell-dilaton-Lambda theories,
and gauged or ungauged supergravity theories with U(1) Maxwell fields. Our
three theorems are: (1) The near horizon geometry of any EVH black hole has a
three dimensional maximally symmetric subspace. (2) If the energy momentum
tensor of the theory satisfies strong energy condition either this 3d part is
an AdS3, or the solution is a direct product of a locally 3d flat space and a
d-3 dimensional part. (3) These results extend to the near horizon geometry of
near-EVH black holes, for which the AdS3 part is replaced with BTZ geometry.Comment: 5 page
On Classification of Geometries with SO(2,2) Symmetry
Motivated by the Extremal Vanishing Horizon (EVH) black holes, their near
horizon geometry and the EVH/CFT proposal, we construct and classify solutions
with (local) SO(2,2) symmetry to four and five dimensional
Einstein-Maxwell-Dilaton (EMD) theory with positive, zero or negative
cosmological constant Lambda, the EMD- theory, and also
gauged supergravity in four dimensions and gauged supergravity in five
dimensions. In four dimensions the geometries are warped product of AdS3 with
an interval or a circle. In five dimensions the geometries are of the form of
warped product of AdS3 and a 2d surface . For the
Einsten-Maxwell- theory we prove that should have a U(1)
isometry, a rigidity theorem in this class of solutions. We also construct all
d dimensional Einstein vacuum solutions with or
isometry.Comment: 26 pages, updated to published versio
Near Horizon Structure of Extremal Vanishing Horizon Black Holes
We study the near horizon structure of Extremal Vanishing Horizon (EVH) black
holes, extremal black holes with vanishing horizon area with a vanishing
one-cycle on the horizon. We construct the most general near horizon EVH and
near-EVH ansatz for the metric and other fields, like dilaton and gauge fields
which may be present in the theory. We prove that (1) the near horizon EVH
geometry for generic gravity theory in generic dimension has a three
dimensional maximally symmetric subspace; (2) if the matter fields of the
theory satisfy strong energy condition either this 3d part is AdS, or the
solution is a direct product of a locally 3d flat space and a dimensional
part; (3) these results extend to the near horizon geometry of near-EVH black
holes, for which the AdS part is replaced with BTZ geometry. We present
some specific near horizon EVH geometries in 3, 4 and 5 dimensions for which
there is a classification. We also briefly discuss implications of these
generic results for generic (gauged) supergravity theories and also for the
thermodynamics of near-EVH black holes and the EVH/CFT proposal.Comment: 26 page
Near Horizon Structure of Extremal Vanishing Horizon Black Holes
We study the near horizon structure of Extremal Vanishing Horizon (EVH) black
holes, extremal black holes with vanishing horizon area with a vanishing
one-cycle on the horizon. We construct the most general near horizon EVH and
near-EVH ansatz for the metric and other fields, like dilaton and gauge fields
which may be present in the theory. We prove that (1) the near horizon EVH
geometry for generic gravity theory in generic dimension has a three
dimensional maximally symmetric subspace; (2) if the matter fields of the
theory satisfy strong energy condition either this 3d part is AdS, or the
solution is a direct product of a locally 3d flat space and a dimensional
part; (3) these results extend to the near horizon geometry of near-EVH black
holes, for which the AdS part is replaced with BTZ geometry. We present
some specific near horizon EVH geometries in 3, 4 and 5 dimensions for which
there is a classification. We also briefly discuss implications of these
generic results for generic (gauged) supergravity theories and also for the
thermodynamics of near-EVH black holes and the EVH/CFT proposal.Comment: 26 page
Effect of air pollution on onset of acute coronary syndrome in susceptible subgroups
While long-term exposure to air pollutants is associated with an increase in heart diseases and mortality, little information is available about the short-term effects of air pollution. This case-crossover study assessed the relationship of particulate matter (PM10) and carbon monoxide (CO) levels with hospital admission for acute coronary syndrome in Tehran, Islamic Republic of Iran. We interviewed 250 patients with a first episode of acute coronary syndrome and obtained data from hospital records and Tehran Air Quality Control Company. The risk of acute coronary syndrome was significantly associated with elevated concentrations of CO the day before the event (OR 1.18; 95% CI: 1.03-1.34) but not significantly with PM10 (OR 1.00; 95% CI: 0.99-1.02). Stratification by age, sex, diabetes, hypertension and smoking status did not affect the results, but women were more susceptible than men to CO levels (OR for women/men 1.68; 95% CI: 1.25-2.26)
An Experimental Investigation on the Amount of Drag Force of Sand on a Cone Moving at Low Uniform Speed
The amount of resistance of a particular medium like soil to the moving objects is the interest of many areas in science. These include soil mechanics, geotechnical engineering, powder mechanics etc. Knowledge of drag force is also used for estimating the amount of momentum of fired objects like bullets. This paper focuses on measurement of drag force of sand on a cone when it moves at a low constant speed. A 30-degree apex angle cone has been used for this purpose. The study consisted of both loose and dense conditions of the soil. The applied speed has been in the range of 0.1 to 10 mm/min. The results indicate that the required force is basically independent of the cone speed; but, it is very dependent on the material densification and confining stress
Force, orientation and position control in redundant manipulators in prioritized scheme with null space compliance
This paper addresses the problem of executing multiple prioritized tasks for robot manipulators with compliant behavior in the remaining null space. A novel controller–observer is proposed to ensure accurate accomplishment of various tasks based on a predefined hierarchy using a new priority assignment approach. Force control, position control and orientation control are considered. Moreover, a compliant behavior is imposed in the null space to handle physical interaction without using joint torque measurements. Asymptotic stability of the task space error and external torque estimation error during executing multiple tasks are shown. The performance of the proposed approach is evaluated on a 7R light weight robot arm by several case studies
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