122 research outputs found
Order in a Spatially Anisotropic Triangular Antiferromagnet
The phase diagram of the spin-1/2 Heisenberg antiferromagnet on an
anisotropic triangular lattice of weakly coupled chains, a model relevant to
Cs2CuCl4, is investigated using a renormalization group analysis, which
includes marginal couplings important for connecting to numerical studies of
this model. In particular, the relative stability of incommensurate spiral
spin-density order and collinear antiferromagnetic order is studied. While
incommensurate spiral order is found to exist over most of the phase diagram in
the presence of a Dzyaloshinskii-Moriya (DM) interaction, at small interchain
and extremely weak DM couplings, collinear antiferromagnetic order can survive.
Our results imply that Cs2CuCl4 is well within the part of the phase diagram
where spiral order is stable. The implications of the renormalization group
analysis for numerical studies, many of which have found spin-liquidlike
behavior, are discussed.Comment: 10 pages, 7 figures, minor edits and reference adde
Reliability Modeling for the Advanced Electric Power Grid
The advanced electric power grid promises a self-healing infrastructure using distributed, coordinated, power electronics control. One promising power electronics device, the Flexible AC Transmission System (FACTS), can modify power flow locally within a grid. Embedded computers within the FACTS devices, along with the links connecting them, form a communication and control network that can dynamically change the power grid to achieve higher dependability. The goal is to reroute power in the event of transmission line failure. Such a system, over a widespread area, is a cyber-physical system. The overall reliability of the grid is a function of the respective reliabilities of its two major subsystems, namely, the FACTS network and the physical components that comprise the infrastructure. This paper presents a mathematical model, based on the Markov chain imbeddable structure, for the overall reliability of the grid. The model utilizes a priori knowledge of reliability estimates for the FACTS devices and the communications links among them to predict the overall reliability of the power grid
Effect of foot reflexology on anxiety and agitation in patients under mechanical ventilation after open heart surgery: A randomized clinical trial study
زمینه و هدف: رویکردهای غیر دارویی از جمله ماساژ بازتابی پا به علت کاهش عوارض و هزینه ها در کانون توجه محققین در جامعه بیماران مختلف قرار گرفته است. این مطالعه با هدف بررسی تأثیر ماساژ بازتابی پا بر اضطراب و بیقراری بیماران تحت تهویه مکانیکی پس از جراحی قلب باز انجام شد. روش بررسی: این مطالعه کارآزمایی بالینی کنترل شده، سه گروهی و دو سو کور با طراحی اندازه گیری مکرر در دو بیمارستان وابسته به دانشگاه علوم پزشکی بقیه الله (عج) تهران، از بهمن1392 تا اردیبهشت 1393 انجام شد. 96 بیمار کاندید جراحی قلب باز به روش نمونه گیری در دسترس انتخاب و به صورت تخصیص تصادفی در سه گروه آزمون (ماساژ بازتابی پا 34 نفر)، درمان نما (تماس سطحی پاشنه پا 30 نفر) و کنترل (مراقبت های معمول 32 نفر) قرار گرفتند. در گروه آزمون، ماساژ بازتابی پا به مدت20 دقیقه بر روی نقاط بازتاب قلب و ریه، انجام شد. میزان اضطراب و بیقراری بر اساس مقیاس سنجش اضطراب (FAS) و مقیاس سنجش بیقراری ریچموند (RSAS) در 6 مرحله زمانی ثبت شد. یافته ها: داده های آماری 92 بیمار (31 نفر گروه آزمون، 30 نفر گروه درمان نما و 31 نفر گروه کنترل) جمع آوری گردید. در مقایسه روند تغییرات سطح اضطراب و بیقراری، آزمون درون گروهی فریدمن نشان داد، بین میانگین سطح اضطراب و بیقراری در گروه ها در مراحل زمانی مختلف تفاوت معنی دار آماری وجود دارد. همچنین آزمون کروسکال والیس نشان داد میزان اضطراب و بیقراری بین سه گروه در مراحل مختلف زمانی تفاوت معنی دار آماری با یکدیگر ندارند. نتیجه گیری: ماساژ بازتابی پا در نقاط بازتابی مربوط به قلب و ریه تغییر معنی داری در کاهش اضطراب و بیقراری بیماران پس از جراحی ایجاد نکرد
Emergence of Multidrug Resistance and Metallo‑beta‑lactamase Producing Acinetobacter baumannii Isolated from Patients in Shiraz, Iran
Background: Metallo‑beta‑lactamase (MβL) enzymes production is one of the most important resistance mechanisms against carbapenems in some bacteria including Acinetobacter baumannii. Aims: This study was aimed to determine the antimicrobial susceptibility and the prevalence of MβL among carbapenem‑resistant isolates of A. baumannii. Materials and Methods: In this cross‑sectional study from October 2012 to April 2013, 98 isolates were identified as A. baumannii using Microgen™ kits and confirmed by molecular method. These isolates were tested for antimicrobial susceptibilities by disk diffusion method according to the Clinical and Laboratory Standards Institute guidelines. Carbapenem‑resistant isolates were further detected phenotypically by MβL minimal inhibitory concentration (MIC)‑test strips, and subsequently positive MβL isolates were confirmed by polymerase chain reaction (PCR). Results: Overall, 98% (96/98) of A. baumannii isolates were detected as carbapenem‑resistant by MIC test. Highest sensitivity to the tested antibiotic with 42.9% (42/98) was observed to colistin. Of 96 carbapenem‑resistant isolates, 43 were phenotypically positive for MβL; out of 43 isolates, 37 were confirmed for the presence of MβL genes by PCR. Conclusion: The frequency of drug resistance among the clinical samples of A. baumannii isolated in our study against most of the antibiotics was very high. Moreover, all MβL producing isolates were multidrug resistance. Therefore, systematic surveillance to detect MβL producing bacteria and rational prescription and use of carbapenems could be helpful to prevent the spread of carbapenem resistance.Keywords: Acinetobacter baumannii, Antibiotic resistance, Carbapenem, Iran, Metallo‑beta‑lactamas
A Comparative Study Between 2 Different Grafts Used as Patches After Plaque Incision and Inflatable Penile Prosthesis Implantation for End-Stage Peyronie's Disease
A New, Innovative, Lengthening Surgical Procedure for Peyronie's Disease by Penile Prosthesis Implantation with Double Dorsal-Ventral Patch Graft: The "Sliding Technique"
The effect of surgical preference card on the clinical self-efficacy of operating room students
Background & Aim: A wide range of clinical education of operating room students is done in the operating room. One of the problems in students' clinical education is the lack of appropriate learning tools in the operating room. The use of educational tools that improve students' performance affects students' self-efficacy in the operating room. So, the purpose of this study was to investigate the influence of the surgical preference card as an educational aid tool on the self-efficacy of the operating room students. Methods & Materials: This quasi-experimental study was carried out on 64 operating room students of Isfahan University of Medical Sciences at AL-Zahra Hospital in the year 2018. Participates were selected through convenience sampling and were divided into experimental (n=32) and control (n=32) groups. The students in the intervention group performed surgical care with using the surgical preference card. The data collection tool was a clinical self-efficacy questionnaire. Data were analyzed with SPSS-21 software using the independent-t, paired t-test, and chi-square test. Results: The findings of this study showed that there was no significant difference between the average self-efficacy score of the control group before and after the intervention (p>0.05). while the average self-efficacy score of the experimental group increased significantly after the intervention as compared with before the intervention (p <0.001). Conclusion: The surgical preference card as an educational aid tool improved the students' self-efficacy. Therefore, it is recommended to use this tool for the clinical education of other operating room students. © 2020, Tehran University of Medical Sciences. All rights reserved
Fault & Fracture Development in Foreland Fold and Thrust Belts - Insight from the Lurestan Province, Zagros Mountains, Iran
Second Arabian Plate Geology Workshop Abu Dhabi, UAE, 24 - 27 January 2010The Simply Folded Belt of the Zagros Mountains, Iran, represents one of the best
examples of foreland fold and thrust belt. A regional fault and fracture analysis of the
Cenomanian ¿ Coniacian Ilam and Sarvak formations, exposed in southern Lurestan
Province, is presented as a case study for fault and fracture development in folded
belts. The area is characterised by the occurrence of gentle to tight anticlines and
synclines whose NW-SE axial traces are parallel to the general trend of the belt. Fold
style is intimately related to both vertical and lateral facies distribution. The two
formations belong to the Bangestan Group and, in this area, they represent the oldest
strata exposed in the core of most anticlines outcropping at surface.
Distribution, kinematics and timing of faults and fractures have been characterised
through extensive fieldwork and interpretation of orthorectified QuickBird imagery
and 3-D virtual outcrop models based on LiDAR technology. Data have been
collected from 10 anticlines covering an area of approximately 150 x 150 km. Key
outcrops for fracture and fault kinematics interpretations are presented.
Field observations and interpretation of QuickBird and 3-D photorealistic models
suggest a complex fault and fracture geometry and timing relationship. Both fractures
and faults record pre-folding to uplift-related deformations. Pre-folding structures are
typically represented by small-scale, flat-ramp-flat geometry thrusts, systematic veins
and stylolites, which are superimposed on inherited syn-sedimentary normal faults.
Folding-related structures generally reactivated pre-existing fracture and fault planes.
Strike-slip faulting is typically recorded as the last faulting event and is probably
related to late stage of fold tightening. All structures are geometrically and
kinematically consistent with the trend of the Arabian passive margin and its
subsequent tectonic inversion. Uplift and stress release induced opening and
propagation of through-going fractures.
Faults and fracture orientations generally change accordingly with local fold trend.
Symmetry between fracture and fold orientation, although commonly interpreted as
evidence for folding-related fracture development, is here interpreted as evidence of
syn- to post-folding local vertical axis passive rotation
Clinical outcomes and temporal trends of immunological and non-immunological rare diseases in adult kidney transplant
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