Polarization modulation by vanadium dioxide on metallic substrates

Vanadium dioxide (VO2) undergoing phase transition is known alters the polarization state of light in reflection owing to large changes in complex refractive indices. While this effect is promising for optical modulation applications, the usual VO2 films on dielectric substrates tend to offer limited tunability for polarization modulation. In this paper, we show that metallic under-layers greatly enhance the performance by widening the spectral range and include visible wavelengths, by increasing the polarization modulation amplitude, and by widening the range of workable incidence angles. The imaginary part of the refractive index in the metallic layer is found to increase the relative phase shifts between s- and p-components of polarization as well as increasing the reflectance

STUDY ON FLUORINATION AND HYDROGENATION IN TRANSPARENT CONDUCTING ZINC OXIDE THIN FILMS

Fluorination and hydrogenation are known as two methods for enhancing crystalline structural and electrical properties of ZnO material. The ZnO thin films normally require a low resistivity and a high transmittance for using as high-performance transparent electrodes in optoelectronic applications. In this study, we report successful preparation of fluorinated and hydrogenated ZnO thin films (FZO and HFZO) by using d.c. magnetron sputtering technique. The hydrogenation was carried out by depositing the films in hydrogen plasma atmosphere, while a highly-sintered body of ZnO and ZnF2 compound was employed as a sputtering target for the fluorination. The results show that the strong improvements in carrier concentration, mobility and resistivity of the FZO and HFZO films as compared to the pure ZnO films. The carrier concentration increases to 2x1020 cm-3 which is mainly due to the hydrogenation. The effect combination of the fluorination and the hydrogenation is responsibility for enhancing the mobility up to 43 cm2/Vs. These results give rise to two-order reduction in resistivity, from 0.06 Ohm.cm (ZnO) to 7.5x10-4 Ohm.cm (HFZO), which can be a good choice for thin-film electrode application. In addition, the crystalline structure and optical transmission of the films are also discussed

On the Performance of a Simple Approximation Algorithm for the Longest Path Problem

The longest path problem is known to be NP-hard. Moreover, they cannot be approximated within a constant ratio, unless ${\rm P=NP}$. The best known polynomial time approximation algorithms for this problem essentially find a path of length that is the logarithm of the optimum.In this paper we investigate the performance of an approximation algorithm for this problem in almost every case. We show that a simple algorithm, based on depth-first search, finds on almost every undirected graph $G=(V,E)$ a path of length more than $|V|-3\sqrt{|V| \log |V|}$ and so has performance ratio less than $1+4\sqrt{\log |V|/|V|}$.

Human Resource Management Practices and Firm Outcomes: Evidence from Vietnam

Using a panel sample of manufacturing firms from small- and medium-sized enterprise surveys between 2009 and 2013, we estimate the causal effects on firm outcomes of human resource management practices at the firm level in Vietnam. Employing a fixed-effects framework for the estimation, we find that on average a firm that provides the training for new workers gains roughly 13.7%, 10% and 14.9% higher in output value per worker, value added per worker and gross profit per worker respectively than the counterpart. Moreover, an additional ten-day training duration for new employees on average leads to 4.1% increase in output value per worker, 3.0% rise in value added per worker and 3.0% growth in gross profit per worker. We also uncover that a marginal 10% of HRM spending results in about 2% and 1.6% rises in output value per worker and value added per worker, respectively. Nevertheless, we find no statistically significant impacts of incentive measure on firm outcomes. The estimated results are strongly robust to various specifications

Human Resource Management Practices and Firm Outcomes: Evidence from Vietnam

Using a panel sample of manufacturing firms from small- and medium-sized enterprise surveys between 2009 and 2013, we estimate the causal effects on firm outcomes of human resource management practices at the firm level in Vietnam. Employing a fixed-effects framework for the estimation, we find that on average a firm that provides the training for new workers gains roughly 13.7%, 10% and 14.9% higher in output value per worker, value added per worker and gross profit per worker respectively than the counterpart. Moreover, an additional ten-day training duration for new employees on average leads to 4.1% increase in output value per worker, 3.0% rise in value added per worker and 3.0% growth in gross profit per worker. We also uncover that a marginal 10% of HRM spending results in about 2% and 1.6% rises in output value per worker and value added per worker, respectively. Nevertheless, we find no statistically significant impacts of incentive measure on firm outcomes. The estimated results are strongly robust to various specifications

Effects of protein levels of commercial diets on the growth performance and survival rate of rabbitfish (Siganus guttatus) at the nursing stage

This study aimed to determine the effect of a commercial diet's protein level on the fry-to-fingerling stage. Thirty days-old fries having the initial length and weight of 18.25 ± 0.15 mm fish-1 and 0.036 ± 0.50 g fish-1 respectively have been used in this study. Diet having three protein levels i.e. 30% (trial 1 as control), 35% (trial 2), 40% (trial 3), and 45% (trial 4), respectively, have been used to evaluate the effect of protein, and each trial has been repeated three times. During the study, stocking density was allocated to 1000 fish per composite tank with a volume of 1 m3. After 30 days of rearing, the weight of fingerlings in trial 1 reached up to 1.50 ± 0.02 g fish-1 and it was recorded as 1.52 ± 0.01g for trial 2, these two were lower than that of trials 3 and 4, where fingerling weight was reported 1.69 ± 0.01 and 1.58g fish-1 respectively and obtained the best weight compared to others. The length of fingerlings at the end of the experimental period was also changed in different trials and it was recorded 47.12; 46.92; 50.97; and 48.89 mm fish-1 for trail 1, 2, 3, and 4 respectively, among the tested combinations lower fingerlings length was recorded for trial 2 (35% CP), but it is not significantly different for trial 1 and 2 and a significant difference (P < 0.05) was reported for trail 2, 3, and 4. The survival rate of fingerlings ranged from 67.27 to 72.33%. Meanwhile, the herd distribution coefficient variation (CVW) in the treatment using 40% protein (trial 3) was the highest at 72.33% (p < 0.05). The results of the study can be concluded that the level of protein has a significant effect on the various growth parameters of fingerlings

THE CURRENT CONDITIONS OF PROMOTING THE PHYSICAL EDUCATION AND SPORTS ACTIVITIES FOR STUDENTS AT VIETNAM NATIONAL UNIVERSITY, HO CHI MINH CITY

The purpose of the study was to have a comprehensive understanding of the existing conditions assured to give physical education (PE) programs to students at Vietnam National University, Ho Chi Minh City (VNUHCM). Through document synthesis, interviews, and statistical processing, the article gained a general evaluation of the current PE conditions according to the following aspects: facilities, administration, and curriculums. In terms of facilities, the total space for sports activities at VNUHCM is measured at 25,454m2, besides, the ratio of sports field area per student is 0.44m2/student. This indicates that VNUHCM’s students do not have enough space for their sports practice as standard. In terms of faculty, teachers at VNUHCM Sports Center are comprised 67.6% male, 88.2% at the age of thirty to fifty, and 100% holding postgraduate qualifications. In addition, 79.4% of the staff at the VNUHCM Sports Center graduated with PE specialized degrees, and 64.7% of them have less than five years of seniority. However, 68.8% of those who are currently delivering PE courses at this Center are visiting teachers. The statistic number reveals that the ratio of students per teacher at VNUHCM is 814.75 students/teacher, which reveals that the number of PE lecturers has not met the standard, and they have been in charge of a large teaching volume. In terms of curriculums, PE programs are conducted with 06 credits in total (90 periods), divided into 02 modules with 3 credits per each (45 periods). Students are allowed to choose their favorite PE content among 10 sports courses including football, volleyball, basketball, table tennis, tennis, badminton, martial arts, aerobics, swimming, and chess. The results indicate that VNUHCM’s students actively participate in sports training and competitions to advance their physical fitness.  Article visualizations

Lovastatin for adult patients with dengue: protocol for a randomised controlled trial.

BACKGROUND: Dengue is the most important vector-borne viral infection of man, with approximately 2 billion people living in areas at risk. Infection results in a range of manifestations from asymptomatic infection through to life-threatening shock and haemorrhage. One of the hallmarks of severe dengue is vascular endothelial disruption. There is currently no specific therapy and clinical management is limited to supportive care. Statins are a class of drug initially developed for lipid lowering. There has been considerable recent interest in their effects beyond lipid lowering. These include anti-inflammatory effects at the endothelium. In addition, it is possible that lovastatin may have an anti-viral effect against dengue. Observational data suggest that the use of statins may improve outcomes for such conditions as sepsis and pneumonia. This paper describes the protocol for a randomised controlled trial investigating a short course of lovastatin therapy in adult patients with dengue. METHODS/DESIGN: A randomised, double-blind, placebo-controlled trial will investigate the effects of lovastatin therapy in the treatment of dengue. The trial will be conducted in two phases with an escalation of dose between phases if an interim safety review is satisfactory. This is an exploratory study focusing on safety and there are no data on which to base a sample size calculation. A target sample size of 300 patients in the second phase, enrolled over two dengue seasons, was chosen based on clinical judgement and feasibility considerations. In a previous randomised trial in dengue, about 10% and 30% of patients experienced at least one serious adverse event or adverse event, respectively. With 300 patients, we will have 80% power to detect an increase of 12% (from 10% to 22%) or 16% (from 30% to 46%) in the frequency of adverse events. Furthermore, this sample size ensures some power to explore the efficacy of statins. DISCUSSION: The development of a dengue therapeutic that can attenuate disease would be an enormous advance in global health. The favourable effects of statins on the endothelium, their good safety profile and their low cost make lovastatin an attractive therapeutic candidate. TRIAL REGISTRATION: International Standard Randomised Controlled Trial Number ISRCTN03147572

Spondylolysis-induced Multilevel Lumbar Spondylolisthesis; Challenges in Lumbar Spine Surgery

Lumbar spondylolysis and multilevel lumbar spondylolysis account for 4.4-5.8% and 0.3% of the general population, and multilevel lumbar spondylolysis resulting in spondylolisthesis is even rarer. Herein, we report two cases of three-level lumbar spondylolisthesis because of spondylolysis: A 49-year-old woman was admitted to the hospital for dull lower back pain over the past 8 months, with exacerbating symptoms when standing and walking. Spasticity at lumbar region and radiculopathy at S1 nerve root was found on examination and a 63-year-old man was admitted to the hospital because of numbness and perianal sensory disturbances with difficulty urinating 2 weeks ago, the symptoms gradually increased to the time of examination. Both patients were diagnosed with multilevel lumbar spondylolisthesis because of spondylolysis and were indicated for posterior lumbar interbody fusion (PLIF). After surgery, both patients recovered well without any significant complications. The improved treatment results suggest the application of PLIF technique to treat spondylolysis-induced multilevel lumbar spondylolisthesis

A prospective multi-center observational study of children hospitalized with diarrhea in Ho Chi Minh City, Vietnam.

We performed a prospective multicenter study to address the lack of data on the etiology, clinical and demographic features of hospitalized pediatric diarrhea in Ho Chi Minh City (HCMC), Vietnam. Over 2,000 (1,419 symptomatic and 609 non-diarrheal control) children were enrolled in three hospitals over a 1-year period in 2009-2010. Aiming to detect a panel of pathogens, we identified a known diarrheal pathogen in stool samples from 1,067/1,419 (75.2%) children with diarrhea and from 81/609 (13.3%) children without diarrhea. Rotavirus predominated in the symptomatic children (664/1,419; 46.8%), followed by norovirus (293/1,419; 20.6%). The bacterial pathogens Salmonella, Campylobacter, and Shigella were cumulatively isolated from 204/1,419 (14.4%) diarrheal children and exhibited extensive antimicrobial resistance, most notably to fluoroquinolones and third-generation cephalosporins. We suggest renewed efforts in generation and implementation of policies to control the sale and prescription of antimicrobials to curb bacterial resistance and advise consideration of a subsidized rotavirus vaccination policy to limit the morbidity due to diarrheal disease in Vietnam