266 research outputs found

    Assessing the validity of western measurement of online risks to children in an Asian context

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    Before the advent of the Internet, television with limited channels was the only media choice that most children were exposed to, and took place under family supervision. Children’s television viewing was controllable and the risks were limited to watching sexual and violent content. Nowadays, children are surrounded by a variety of digital media and are exposed to many different risks, many of which are still unknown and under-researched. For many children, the Internet is fully integrated into their daily lives, along with the potential risks. The present study aimed to (i) describe the level of risks children are exposed to, and (2) test the measurement validity of a total of 45 items assessing nine scales online risky behavior in children were adapted from studies carried out in Europe and the United States. The study comprised 420 school going children aged 9, 11, 13, 14, and 16 studying in Malaysia. Descriptive analyses showed that children were more exposed to ‘unwanted exposure to pornography’ and less to ‘conduct risk’. Boys and older children were more exposed to the risks compared to girls and younger children. The study validated five dimensions (inappropriate materials, sexting, contact-related risks on, risky online sexual behavior, and bullying/being bullied) assessing children’s online risky behavior by using exploratory and confirmatory factor analyses. Further research is needed to investigate the measurement of children’s online risk, since the scales developed in Europe and the United States are not wholly suitable to an Asian context

    EFFECT OF DIET DILUTION IN THE STARTER PERIOD ON PERFORMANCE AND CARCASS CHARACTERISTICS OF BROILER CHICKS

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    The effect of energy and protein dilution in the starter period (8 to 14 days) of age, on performance and carcass characteristics of 360 Arian male chicks was studied in a completely randomised design. This experiment consisted of 6 treatments, 4 replicates, with 15 chicks per replicate. In order to dilute the diets six levels (0, 4, 8, 12, 16, and 20) percent of ground wood charcoal was used. Chicks were fed with starter and grower diet from 15 to 21 and 22 to 42 days of age respectively. During the experiment feed intake, body weight gain, feed conversion ratio were measured weekly. Mortality was measured throughout the experiment. At 43 day of age 4 chicks each treatment was selected and carcass characteristics were measured. The results indicated that dilution of diet from 8 to 14 days of age increased feed intake in this period but the differences were not signifi cant. With increasing dilution rate body weight gain of chicks signifi cantly decreased in comparison to control group (P< 0.05). Due to compensatory growth after restricted period, there was not signifi cant difference in body weight among restricted and control groups at 42 days of age. There was not signifi cant difference among the treatments for feed conversion ratio in whole period of the experiment (8 to 42 day). Similarly, there was not signifi cant difference among the treatments for caloric conversion ratio in whole period of the experiment (8 to 42 day). Mortality rate in restricted groups was signifi cantly lower than control group (P<0.05). Diet dilution hadn’t signifi cant effect on carcass, breast meat, drumsticks, thighs, liver, intestine, abdominal fat percentages. The results of the present study indicated that broiler chicks could withstand a 7-day period (from 8 to 14 days) feed restriction with ground wood charcoal in early age without loss in performance

    Investigating 2d and 3d convolutions for multitemporal land cover classification using remote sensing images

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    With the availability of large amounts of satellite image time series (SITS), the identification of different materials of the Earth's surface is possible with a high temporal resolution. One of the basic tasks is the pixel-wise classification of land cover, i.e.The task of identifying the physical material of the Earth's surface in an image. Fully convolutional neural networks (FCN) are successfully used for this task. In this paper, we investigate different FCN variants, using different methods for the computation of spatial, spectral, and temporal features. We investigate the impact of 3D convolutions in the spatial-Temporal as well as in the spatial-spectral dimensions in comparison to 2D convolutions in the spatial dimensions only. Additionally, we introduce a new method to generate multitemporal input patches by using time intervals instead of fixed acquisition dates. We then choose the image that is closest in time to the middle of the corresponding time interval, which makes our approach more flexible with respect to the requirements for the acquisition of new data. Using these multi-Temporal input patches, generated from Sentinel-2 images, we improve the classification of land cover by 4% in the mean F1-score and 1.3% in the overall accuracy compared to a classification using mono-Temporal input patches. Furthermore, the usage of 3D convolutions instead of 2D convolutions improves the classification performance by a small amount of 0.4% in the mean F1-score and 1.2% in the overall accuracy

    Comparison of the effect of letrozole alone with letrozole plus n-acetylcysteine on pregnancy rate in patients with polycystic ovarian syndrome: A randomized clinical trial

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    Objectives: Different drugs are prescribed for the induction of ovulation in patients with polycystic ovary syndrome (PCOS). The aim of this study was to compare the effect of letrozole alone with letrozole plus N-acetyl cysteine (NAC) on the pregnancy rate in patients with PCOS. Materials and Methods: This clinical trial studyincluded317 patients with PCOS in the infertility clinic of Zahedan in 2018. Patients were randomly divided into letrozole and NAC plus letrozole groups. Then, several parameters were evaluated in both groups, including the pregnancy rate, number of follicles larger than 18 mm, endometrial thickness, and the endometrial pattern. Finally, data were analyzed using SPSS 25, and t-test and chi-square tests were used for statistical analysis. Results: The mean age of study participants was 28.5 ± 4.9 years old. The mean duration of infertility in the intervention group was 4.5 ± 3.8 years. The mean anti-MĂƒÂŒllerian hormone and the mean endometrial thickness of patients in the intervention group were 4.4± 3.6 ng/mL and 7.6 ± 2.5 mm, respectively. Eventually, the pregnancy rate was 14.6 (n = 23) and 7.5 (n = 12) in the intervention and control groups, respectively (P = 0.046). Conclusions: The results of this search revealed that the number of follicles with the size of 18 mm in the control group was higher compared to the intervention group, but the fertility rate in patients with PCOS receiving letrozole plus N-acetylcysteine was significantly higher. © 2021 The Author(s);

    Association between two common transitions of H2BFWT gene and male infertility: a caseĂąïżœïżœcontrol, meta, and structural analysis

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    H2BFWT is one of the testis‐specific histones that plays a fundamental role in spermatogenesis, and single nucleotide polymorphisms (SNPs) in this gene may result in male infertility. This study aimed to investigate the association between −9C>T and 368A>G transitions of H2BFWT gene and male infertility through a case–control, meta‐analysis, and a bioinformatics approach. In this case–control study, 490 subjects including 240 idiopathic infertile men and 250 healthy controls were included. The −9C>T and 368A>G SNPs genotyping were performed by a PCR–RFLP method. To find eligible studies for meta‐analysis, we searched valid scientific databases. The odds ratios with 95% confidence intervals were estimated to find the strength of these associations. Furthermore, the influences of two common transitions on the molecular features of H2BFWT were assessed by in silico tools. Our case–control data revealed that −9C>T is not associated with male infertility. But, there was a significant association between 368A>G and male infertility. In the meta‐analysis, five eligible studies were included. Our data revealed significant associations between −9C>T, 368A>G, and male infertility in overall and stratified analyses. Moreover, structural analysis showed that 368A>G could affect the protein structure (SNAP prediction: non‐neutral, score: 42, expected accuracy: 71%; SIFT prediction: deleterious, score: −2.55), while −9C>T may affect the binding nucleotide in the promoter region. Based on these findings, two aforementioned polymorphisms were associated with increased risk of male infertility. However, studies with larger sample size and different ethnicities are needed to obtain more accurate conclusions

    How Has the COVID-19 Pandemic Affected Students’ Online Social Presence?

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    The coronavirus disease 2019 pandemic has affected higher education institutions worldwide as they had to switch from face-to-face to online teaching almost overnight. This abrupt change made a huge impact on teaching, learning, and particularly, student engagement. This paper focuses on online social presence as an element of student engagement, which represents how students feel under synchronous online teaching. A survey was conducted among 244 first-year students to evaluate the impact of online social interaction, online collaboration, online contact with staff, online engagement, and online active learning on online social presence. Structural equation modeling was used to test and evaluate these multivariate relationships. Our study illustrates that all variables have a significant positive relationship with online social presence. In particular, online social interaction and online collaboration show a more powerful relationship with student online social presence. Thus, digital technologies should be adopted in a way that encourages students to actively interact with their peers

    Utility of Parental Mediation Model on Youth’s Problematic Online Gaming

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    The Parental Mediation Model PMM) was initially designed to regulate children’s attitudes towards the traditional media. In the present era, because of prevalent online media there is a need for similar regulative measures. Spending long hours on social media and playing online games increase the risks of exposure to the negative outcomes of online gaming. This paper initially applied the PMM developed by European Kids Online to (i) test the reliability and validity of this model and (ii) identify the effectiveness of this model in controlling problematic online gaming (POG). The data were collected from 592 participants comprising 296 parents and 296 students of four foreign universities, aged 16 to 22 years in Kuala Lumpur (Malaysia). The study found that the modified model of the five-factor PMM (Technical mediation, Monitoring mediation, Restrictive mediation, Active Mediation of Internet Safety, and Active mediation of Internet Use) functions as a predictor for mitigating POG. The findings suggest the existence of a positive relation between ‘monitoring’ and ‘restrictive’ mediation strategies and exposure to POG while Active Mediation of Internet Safety and Active mediation of Internet use were insignificant predictors. Results showed a higher utility of ‘technical’ strategies by the parents led to less POG. The findings of this study do not support the literature suggesting active mediation is more effective for reducing youth’s risky behaviour. Instead, parents need to apply more technical mediations with their children and adolescents’ Internet use to minimize the negative effects of online gaming

    Using experimental design and response surface methodology (RSM) to optimize gold extraction from refractory sulphidic gold tailings with ionic liquids

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    © 2020 South African Institute of Mining and Metallurgy. All rights reserved. This work examined the feasibility of gold extraction from a pyrite flotation concentrate sample using an ionic liquid and water mixture as solvent, thiourea complexing agent, and iron(III) sulphate oxidant. A design of experiment (DOE) methodology was used to optimize the process parameters. The purpose of the investigation was to determine how feasible it would be to replace the traditional cyanide extraction process by using an alternative approach, and compare the yield that could be obtained with a less environmentally damaging and hazardous combination of chemicals. Test parameters such as ionic liquid concentration, pulp density, time, and temperature were varied using two imidazolium-based ionic liquids: 1-butyl-3-methylimidazolium hydrogen sulphate [Bmim+HSO4–] and 1-butyl-3-methylimidazolium trifluoromethansulphonate [Bmim+CF3SO3–]. The effects on gold extraction were assessed and screened using a half fractional factorial design (25-1) approach. The ionic liquid concentration, pulp density, and temperature had a statistically significant effect on gold extraction, while the type of ionic liquid and extraction time did not affect the gold extraction as much within the operating range investigated. A high gold extraction was obtained at low ionic liquid concentration, low pulp density, and high temperature. A central composite design in conjunction with response surface methodology were used to create an optimization design with the statistically significant parameters in an attempt to establish the optimal gold extraction conditions. It was found that the optimum concentration of ionic liquid [Bmim+HSO4–] in the aqueous solution was 15% (v/v), pulp density was 15% (w/v), and the temperature 60°C, with a gold extraction of 35.7% under these conditions. This, sadly, was only about half of the yield achieved with the cyanide process. In order to compete with the traditional approach, a way will have to be found to completely destroy the pyrite component in the material, in which a substantial portion of the gold was locked up. This work, and similar studies reported in the literature, indicates that cyanide technology for gold recovery will remain the process of choice in the gold industry for the immediate future
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