A case for adaptive sub-carrier level power allocation in OFDMA networks

In today's OFDMA networks, the transmission power is typically fixed and the same for all the sub-carriers that compose a channel. The sub-carriers though, experience different degrees of fading and thus, the received power is different for different sub-carriers; while some frequencies experience deep fades, others are relatively unaffected. In this paper, we make a case of redistributing the power across the sub-carriers (subject to a fixed power budget constraint) to better cope with this frequency selectivity. Specifically, we design a joint power and rate adaptation scheme (called JPRA for short) wherein power redistribution is combined with sub-carrier level rate adaptation to yield significant throughput benefits. We further consider two variants of JPRA: (a) JPRA-CR where, the power is redistributed across sub-carriers so as to support a maximum common rate (CR) across sub-carriers and (b) JPRA-MT where, the goal is to redistribute power such that the transmission time of a packet is minimized. While the first variant decreases transceiver complexity and is simpler, the second is geared towards achieving the maximum throughput possible. We implement both variants of JPRA on our WARP radio testbed. Our extensive experiments demonstrate that our scheme provides a 35% improvement in total network throughput in testbed experiments compared to FARA, a scheme where only sub-carrier level rate adaptation is used. We also perform simulations to demonstrate the efficacy of JPRA in larger scale networks. © 2012 ACM

Comparing the effectiveness of booklet and focus group education of teachers on their knowledge, attitude and performance towards students with attention deficit hyperactivity disorder: a randomized clinical trial

زمینه و هدف: بیش فعالی و نقص توجه (ADHD) شایعترین اختلال روانی کودکان است که منجر به پرتحرکی، نقص توجه و افت تحصیلی دانش آموزان می شود. این مطالعه با هدف مقایسه تأثیر دو روش آموزش غیرحضوری و حضوری بر آگاهی، نگرش و عملکرد معلمان در مورد این اختلال انجام گرفت. روش بررسی: در این کارآزمایی بالینی 60 نفر از معلمان چهار مدرسه ابتدایی دخترانه شهرکرد در سال 92-91 به طور تصادفی انتخاب و به دو گروه 30 نفره آموزش از طریق جلسات Focus Group و آموزش از طریق بوکلت تقسیم گردیدند. گروه اول به دو گروه 15 نفره تقسیم و در چهار جلسه یک ساعته شرکت کردند و گروه دوم جزوه آموزشی با همان محتوا دریافت کردند. پرسشنامه های ارزیابی آگاهی، نگرش به دارو درمانی و عملکرد آن ها در مورد بیش فعالی و نقص توجه قبل و یک ماه بعد از آموزش تکمیل گردید. یافته ها: در هر دو گروه آگاهی شرکت کنندگان بعد از آموزش به طور معنی دار افزایش یافته بود؛ ولی نگرش آن ها به دارو درمانی تغییر قابل توجهی نداشت. بین میانگین نمره آگاهی و نگرش در دو گروه تفاوت آماری معنی داری وجود نداشت؛ ولی در گروه Focus Group نسبت به گروه بوکلت معلمان عملکرد بهتری پیدا کرده بودند، به نحوی که توانسته بودند، تعداد زیادتری از دانش آموزان مشکوک به بیش فعالی را تشخیص و ارجاع دهند. نتیجه گیری: با توجه به نتایج مطالعه که نشان داد آموزش از طریق جلسات Focus Group بهتر از آموزش از طریق بوکلت بر عملکرد معلمان تأثیر دارد، و به دلیل اینکه اختلال ADHD می تواند منجر به مشکلات روانی- اجتماعی در دانش آموزان شود؛ بنابراین توصیه می شود برای شناسایی و ارجاع سریع دانش آموزان مبتلا به اختلال ADHD از آموزش معلمان به روش Focus Group استفاده شود

Present of Three-layered hydro-forming analysis of a new hybrid sandwich tubes using finite element method

Multi-layered tube hydro-forming is suitable to produce multi-layered joints to be used in special application in many industries. With using a middle layer of foam and making sandwich structures, tube bending strength increases when external loads are applied. Also because of the foam is high energy absorption, in the pipelines of major industries such as the nuclear, strength increases when natural disasters, especially earthquakes happen. In this paper for the first time, three-layered new sandwich tube (inner layer of copper, middle layer of aluminum foam and outer layer of annealed brass) hydroforming processes were numerically simulated using finite element method by ABAQUS/Explicit 6.10. As the result of three-layered sandwich tube hydro-forming not reported in the literature, the results of this paper are compared with the latest experimental result of bi-layered tube hydro-forming find in literature by approaching the thickness of middle layer to zero. Finite element analysis shows that numerical and experimental results have a good agreement

EVALUATION OF THE RELATION BETWEEN PELVIC FRACTURE AND ABDOMINAL COMPARTMENT SYNDROME IN TRAUMA PATIENTS WHO REFERED TO NEMAZEE HOSPITAL IN SHIRAZ

Introduction & Objective: Multiple factors can lead to increase in acute abdominal pressure and Abdominal Compartment Syndrome (ACS), such as increase in retroperitoneal volume due to pancreatitis, bleeding and edema due to pelvic fracture. It is observed that sometimes pelvic ring fracture or an open book fracture of pelvic can cause a huge pelvic hematoma in retroperitoneal space that causes abdominal compartment syndrome. Primary ACS problem is often observed during the first 24 hours after sever abdominal and pelvic trauma and surgery. Clinicians, especially nurses, should remember the risk factors for intra abdomen hypertension and should be vigilant to avoid the progression to abdominal compartment syndrome. By measuring the Intra-abdominal pressure through the bladder, we can provide a quick and accurate assessment of abdominal pressure changes and this can be performed by emergency or critical care nurses without a specific medical order or sophisticated invasive monitoring equipment. Regarding this matter that ACS is a very lethal condition. This study’s survey had the intention of finding the relationship between pelvic fracture and abdominal compartment syndrome in trauma patients who refer to Nemazee hospital in Shiraz. Materials & Methods: This research was a descriptive- analytical study that was performed to survey the relationship between pelvic fracture and abdominal compartment syndrome in patients with severe abdominal trauma and pelvic fracture in Nemazee hospital in 2008. Tools for data collection included check list consisting of demographic information and other data required for this research and also intra abdominal pressure (IAP) measurement instruments. The IAP was measured in patients with abdominal trauma who referred to emergency ward via folley catheter indwelling in bladder and pelvic fracture confirmed with pelvic X-ray. Collected data was analyzed by using SPSS software. Results: Of 100 patients with abdominal trauma referred whose abdominal pressure was measured, 28 patients had abdominal compartment syndrome. According to associated injury with abdominal trauma 19% of all patient (19 persons) and 46.42% of the patient with abdominal compartment syndrome (13 persons) had pelvic fracture. Using of qi-sqare test revealed that the relationship between pelvic fracture and incidence rate of abdominal compartment syndrome was significant (P < 0.001). Conclusions: According to our collected data pelvic fracture due to trauma can one of the important causes of increase intra abdominal pressure and abdominal compartment syndrome. In this lethal condition prevention is better than cure. By serial measuring, the Intra abdominal pressure through the bladder in patients at risk, such as pelvic fracture by trauma, nurses can recognize this condition and decrease incidence of mortality

Nursing Students’ viewpoints about Problems of Clinical education

Background:Clinical training is fundamental part of nursing education program and causes the student to apply the theoretical knowledge in caring for patients. The nature and duties of nursing in community is such a special issue that doubles the sensitivity of coordination between theoretical courses and clinical services. About half of nursing and midwifery training time is spent on clinical training but there are many factors that affect the process of clinical education. Therefore the aim of this study is assessing the problems of clinical training in nursing students in clinical environments in Nursing and Midwifery faculty of Isfahan. Methods:This descriptive analytical study was performed on 75 nursing students in their last term. A two-part questionnaire included questions on demographic information and factors to assess clinical training problems in six major areas of problems: problems related to learner, clinical instructor, clinical environment, patient, educational program and clinical evaluation. Data analysis was performed in SPSS software. Results:After analyzing the data the following results were obtained: most of the problems were related to the clinical instructor 78%, learners 73%, clinical environment 71%, clinical training program 66%, clinical evaluation 60% and patient-related problems 43%. Conclusions:Results of this article showed that there are problems in clinical training in nursing, especially in fields that are related to learner and clinical instructor. Due to the fact that Clinical Education is the fundamental part of clinical training and in this type of training, students in interaction with instructors and the environment, apply the learned concepts in the clinical field, by understanding nursing and midwifery clinical education problems, the planners will be able to design good educational programs to increase the quality of health services to all people. Therefore, to reach this goal there is a need to more assessment and continuous clinical evaluation processes

Nursing students’ viewpoints about problems of clinical education

Background:Clinical training is fundamental part of nursing education program and causes the student to apply the theoretical knowledge in caring for patients. The nature and duties of nursing in community is such a special issue that doubles the sensitivity of coordination between theoretical courses and clinical services. About half of nursing and midwifery training time is spent on clinical training but there are many factors that affect the process of clinical education. Therefore the aim of this study is assessing the problems of clinical training in nursing students in clinical environments in Nursing and Midwifery faculty of Isfahan. Methods:This descriptive analytical study was performed on 75 nursing students in their last term. A two-part questionnaire included questions on demographic information and factors to assess clinical training problems in six major areas of problems: problems related to learner, clinical instructor, clinical environment, patient, educational program and clinical evaluation. Data analysis was performed in SPSS software. Results:After analyzing the data the following results were obtained: most of the problems were related to the clinical instructor 78%, learners 73%, clinical environment 71%, clinical training program 66%, clinical evaluation 60% and patient-related problems 43%. Conclusions:Results of this article showed that there are problems in clinical training in nursing, especially in fields that are related to learner and clinical instructor. Due to the fact that Clinical Education is the fundamental part of clinical training and in this type of training, students in interaction with instructors and the environment, apply the learned concepts in the clinical field, by understanding nursing and midwifery clinical education problems, the planners will be able to design good educational programs to increase the quality of health services to all people. Therefore, to reach this goal there is a need to more assessment and continuous clinical evaluation processes

Magnetic properties, domain-wall creep motion, and the Dzyaloshinskii-Moriya interaction in Pt/Co/Ir thin films

We study the magnetic properties of perpendicularly magnetized Pt/Co/Ir thin films and investigate the domain-wall creep method of determining the interfacial Dzyaloshinskii-Moriya (DM) interaction in ultrathin films. Measurements of the Co layer thickness dependence of saturation magnetization, perpendicular magnetic anisotropy, and symmetric and antisymmetric (i.e., DM) exchange energies in Pt/Co/Ir thin films have been made to determine the relationship between these properties. We discuss the measurement of the DM interaction by the expansion of a reverse domain in the domain-wall creep regime. We show how the creep parameters behave as a function of in-plane bias field and discuss the effects of domain-wall roughness on the measurement of the DM interaction by domain expansion. Whereas modifications to the creep law with DM field and in-plane bias fields have taken into account changes in the energy barrier scaling parameter α, we find that both α and the velocity scaling parameter v₀ change as a function of in-plane bias field

Anderson Transition in Disordered Graphene

We use the regularized kernel polynomial method (RKPM) to numerically study the effect disorder on a single layer of graphene. This accurate numerical method enables us to study very large lattices with millions of sites, and hence is almost free of finite size errors. Within this approach, both weak and strong disorder regimes are handled on the same footing. We study the tight-binding model with on-site disorder, on the honeycomb lattice. We find that in the weak disorder regime, the Dirac fermions remain extended and their velocities decrease as the disorder strength is increased. However, if the disorder is strong enough, there will be a {\em mobility edge} separating {\em localized states around the Fermi point}, from the remaining extended states. This is in contrast to the scaling theory of localization which predicts that all states are localized in two-dimensions (2D).Comment: 4 page

Flux pinning mechanism in BaFe1.9Ni0.1As2 single crystals: Evidence for fluctuation in mean free path induced pinning

The flux pinning mechanism of BaFe1.9Ni0.1As2 superconducting crystals have been investigated systematically by magnetic measurements up to 13 T at various temperatures. The field dependence of the critical current density, Jc, was analysed within the collective pinning model. A remarkably good agreement between the experimental results and theoretical dl pinning curve is obtained, which indicates that pinning in BaFe1.9Ni0.1As2 crystal originates from spatial variation of the mean free path. Moreover, the normalized pinning force density, Fp, curves versus h1/4B/Birr (Birr is the irreversibility field) were scaled using the Dew-Hughes model. Analysis suggests that point pinning alone cannot explain the observed field variation of Fp

COMPARISON OF SECOND-DEGREE BURNS HEALING TIME IN TWO METHODS OF DRESSING WITH FUNDERMOL HERBAL OINTMENT AND% 1 SILVER SULFADIAZINE OINTMENT‏

BACKGROUND: Burn wounds are one of the health problems in modern societies that are associated with irreparable harms and many side problems for patients and their families. Infection due to burn wounds is the main cause of death in such patients. One of the methods to prevent infection of burn wounds is topical antibiotic ointments. This study aimed to investigate and identify effective ointments to treat burn wounds. For this purpose, the effects of two types of ointment, fundermol and 1% silver sulfadiazine cream on second degree burn wounds were compared. METHODS: This was a clinical trial study conducted in 2008. Using convenient and continuous sampling method, 50 patients referred to Imam Mousa Kazem Burn Injury Clinic in Isfahan, Iran with 2nd degree burn wounds in 1% to 10% surface area were enrolled. The patients were randomly divided into two groups of treatment with fundermol and sulfadiazine and the dressing was changed once a day. The healing time for burn wounds in each patient was recorded in a checklist and data were analyzed by independent t-test via SPSS software. RESULTS: The healing time of burn wounds in the group treated with fundermol was shorter than that in the group treated with sulfadiazine (p < 0.001). CONCLUSIONS: The present study showed that fundermol ointment accelerates burn wound healing. Therefore, fundermol can be introduced as a good replacement for current treatments of burn wounds