Nursing Student's Viewpoints and Experiences about Clinical Evaluation by 360 Degree Approach

Introduction: One way to confront challenges of clinical evaluation of the students is by means of 360 degree method. Understanding experiences and viewpoints of nursing students as evaluatees are very important. Thus, this study aimed to investigate the experiences and viewpoints of nursing students about clinical evaluation by 360 degree approach. Method: In this qualitative study, junior nursing students attending a pediatric internship program were chosen by purposeful sampling. Focus group sessions were held for data gathering. Totally 27 students participated in 4 focus group discussions. For transcription and analysis of interviews Microsoft Word and OneNote software were used and date were analysed using content analysis approach. Results: “dynamic atmosphere of clinical field” was the main theme of study that consisted of four categories; “active learning”, “justice”, “communication”, and “discipline”. Conclusion: Finding of this study can help nursing instructors to gain a better understanding of the nursing students viewpoints toward this evaluation approach and help them take essential steps and plannings towards implementing this approach. Keywords: 360 degree evaluation, Nursing students experiences, Qualitative stud

Idiopathic Submitral Left Ventricular Aneurysm: an Unusual Substrate for Ventricular Tachycardia in Caucasians

Annular submitral aneurysms have been rarely reported in Caucasians. They are typically diagnosed in non-white adults who present with severe mitral regurgitation, heart failure, systemic embolism, ventricular arrhythmias, and sudden cardiac death. In this article, we describe the case of a white woman, presenting with ventricular tachycardia, who had a large submitral left ventricular aneurysm diagnosed incidentally during coronary angiography

Multi-Hop Wireless Optical Backhauling for LiFi Attocell Networks: Bandwidth Scheduling and Power Control

The backhaul of hundreds of light fidelity (LiFi) base stations (BSs) constitutes a major challenge. Indoor wireless optical backhauling is a novel approach whereby the interconnections between adjacent LiFi BSs are provided by way of directed line-of-sight (LOS) wireless infrared (IR) links. Building on the aforesaid approach, this paper presents the top-down design of a multi-hop wireless backhaul configuration for multi-tier optical attocell networks by proposing the novel idea of super cells. Such cells incorporate multiple clusters of attocells that are connected to the core network via a single gateway based on multi-hop decode-and-forward (DF) relaying. Consequently, new challenges arise for managing the bandwidth and power resources of the bottleneck backhaul. By putting forward user-based bandwidth scheduling (UBS) and cell-based bandwidth scheduling (CBS) policies, the system-level modeling and analysis of the end-to-end multi-user sum rate is elaborated. In addition, optimal bandwidth scheduling under both UBS and CBS policies are formulated as constrained convex optimization problems, which are solved by using the projected subgradient method. Furthermore, the transmission power of the backhaul system is opportunistically reduced by way of an innovative fixed power control (FPC) strategy. The notion of backhaul bottleneck occurrence (BBO) is introduced. An accurate approximate expression of the probability of BBO is derived, and then verified using Monte Carlo simulations. Several insights are provided into the offered gains of the proposed schemes through extensive computer simulations, by studying different aspects of the performance of super cells including the average sum rate, the BBO probability and the backhaul power efficiency (PE).Comment: 36 pages, 21 figures, 1 tabl

Enhancing Solubility and Dissolution of Celecoxib by Nanocrystals

Introduction: Celecoxib is a weakly acidic drug and has low aqueous solubility (3–7 μg/ml). Low solubility of drugs in water results in poor bioavailability because the solubility of a drug is an important factor in determining its absorption rate. According to the Noyes–Whitney equation, the saturation solubility and dissolution rate of poorly water soluble drugs can be enhanced by reducing the particle size, which increases the total surface area. Nanocrystals possess outstanding features enabling to overcome the solubility problems of poorly soluble drugs. The objective of this study was to investigate the dissolution behavior improving effects of differently sized nanocrystals of a poorly soluble model drug, Celecoxib. Methods and Results: Nanocrystals were prepared by antisolvent precipitation followed by high pressure homogenization (HPH) technique in the presence of varying percentage of SLS as a stabilizer (0.2 or 0.4%) and rate of homogenization (26500 or 12500 rpm). The obtained nanoparticles were analyzed in terms of particle size distribution, polydispersity index, saturation solubility, thermal behavior (DSC) and dissolution behavior. The particle size of nanosuspensions was between 140 and 532 nm with poly dispersibility index less than 0.5. That minimum of particle size relate to formulation which contained 0.4% stabilizer with rate of 26500 rpm. This formulation also revealed the highest saturation solubility (18.1 µg/ml) and dissolution efficiency compared to pure Celecoxib. The DSC results indicated the absence of any interactions between drug and stabilizer. These studies showed a decrease in crystalinity of Celecoxib. Conclusions: All microcrystals significantly (P<0.05) increased Celecoxib aqueous solubility and dissolution rate compared to plain drug. This result seemed to be due the significant particle size reduction and decreased drug crystallinity. Significant influence of increasing in rate of homogenizer on size reduction was observed.  As well as, high stabilizer concentration and rate of homogenizer had Significant influence on saturated solubility of Celecoxib compared to pure drug (P<0.05). DSC study showed that there is no change in the crystal structure of Celecoxib during the process and showed that nanocrystals exhibited decreased crystallinity.          &nbsp

Multiple Crack Detection using Wavelet Transforms and Energy Signal Techniques

Wavelet transforms are efficient tools for structural health monitoring (SHM) and damage detection. However, these methods are encountered with some limitations in practice. Thus, signal energy analysis is used as an alternative technique for damage detection. In this paper, discrete wavelet transforms (DWT) and Teager energy operator (TEO) is applied to the curvature of the mode shapes of the beams, and the locations of the damages are identified. The results show that in comparison with the discrete wavelet transform, the signal energy operator has better performance. This superiority in detecting the damages, especially near the supports of the beam, is obvious and has enough sensitivities in low damage intensities. Additionally, the damage detection in the cases that the response data are noisy is investigated. For this purpose, by adding low-intensity noises to the curvature of the mode shapes, the abilities of the mentioned methods are evaluated. The results indicate that each method is not individually efficient in the detection of damages in noisy conditions, but the combination of them under noisy conditions is more reliabl

Weighted Cumulative Past Extropy and Its Inference

This paper introduces and studies a new generalization of cumulative past extropy called weighted cumulative past extropy (WCPJ) for continuous random variables. We explore the following: if the WCPJs of the last order statistic are equal for two distributions, then these two distributions will be equal. We examine some properties of the WCPJ, and a number of inequalities involving bounds for WCPJ are obtained. Studies related to reliability theory are discussed. Finally, the empirical version of the WCPJ is considered, and a test statistic is proposed. The critical cutoff points of the test statistic are computed numerically. Then, the power of this test is compared to a number of alternative approaches. In some situations, its power is superior to the rest, and in some other settings, it is somewhat weaker than the others. The simulation study shows that the use of this test statistic can be satisfactory with due attention to its simple form and the rich information content behind it

Geothermal energy for heating and cooling in agricultural greenhouses

Geothermal source is a perspective technology able to use the ground as a thermal sink or heat source. It is one of the energy resources in Iran that can be used with long-term investment. This study provided a new idea to use of this energy for heating and cooling of buildings. Two wells were used for heating and cooling due to the constant temperature of the water in depth of 12 m underground (approximately is equal  to the annual temperature environment during the year). Water flowed in six speeds: 10, 11.5, 13, 16, 29 and 34 lit/min using a hydraulic pump (12 meters hydraulic height and 2 inch diameter) from first well, and after passing through radiator, discharge to other well. The outdoor temperature was 9oC, 40 °C and 15.5-16 °C for heating, cooling and well water respectively. An axial fan is used to passing the air in six speeds: 0.5, 1.1, 2.2, 3.3, 4.4 and 7.4 m/s through the radiator. The results showed that the use of water from this well can reduce the required power about 25% for heating and increase the air temperature from 9 to 25 °C. Also this system can reduce the required power between 38 to 60% for cooling and decrease the air temperature from 40 to 25 °C