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1.
Internet addiction is “an individual’s inability to control their Internet use, which in turn leads to feelings of distress and functional impairment of daily activities” [Shapira, N., Lessig, M., Goldsmith, T., Szabo, S., Lazoritz, M., Gold, M. et al. (2003). Problematic Internet use: Proposed classification and diagnostic criteria. Depression and Anxiety, 17(4), 207–216]. Previous research in this field has offered inconclusive data on whether Internet addiction can be classified as a disorder. This study provides an in-depth and comprehensive analysis of internet addiction through a meta-synthesis of qualitative studies on excessive Internet use published during the period of 1996–2006. Several constructs pertaining to the domain of Internet addiction have been identified and a theoretical model of Internet addiction has been proposed.  相似文献   
2.
Neurogenetic models predict neuropsychological weaknesses in the relatives of children with attention-deficit/ hyperactivity disorder (ADHD). The authors examined executive and regulatory measures in 386 relatives (307 parents, 79 siblings) of children with ADHD combined type, ADHD inattentive type, and controls. Predicted deficits were seen on trailmaking (relatives of ADHD combined type only), stop-signal reaction times (relatives of girls only), and response variability (mothers only) but not on naming or output speed. Effects generally held, even with relatives' ADHD status controlled. A neuropsychologically impaired subgroup of children with ADHD had relatives with clear neuropsychological weaknesses. The authors conclude that a neurogenetic model of ADHD etiology is supportable only for a subset of executive functions and that neuropsychological heterogeneity warrants more examination in ADHD. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
3.
根据平面散乱点云的特点,依据边界点和非边界点的位置关系,用网格把点云划分开来,在确定边界网格和非边界网格以后,将所有的边界网格按照它们的位置关系连接成环,对于从每一个边界网格提取边界提出了一种最小凸边算法,并且从理论和实验上证明了这种最小凸边算法的可行性。  相似文献   
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5.
There is growing evidence that social media addiction is an evolving problem, particularly among adolescents. However, the absence of an instrument measuring social media addiction hinders further development of the research field. The present study, therefore, aimed to test the reliability and validity of a short and easy to administer Social Media Disorder (SMD) Scale that contains a clear diagnostic cut-off point to distinguish between disordered (i.e. addicted) and high-engaging non-disordered social media users.Three online surveys were conducted among a total of 2198 Dutch adolescents aged 10 to 17. The 9-item scale showed solid structural validity, appropriate internal consistency, good convergent and criterion validity, sufficient test-retest reliability, and satisfactory sensitivity and specificity. In sum, this study generated evidence that the short 9-item scale is a psychometrically sound and valid instruments to measure SMD.  相似文献   
6.
The introduction of Computerized Numeric Control (CNC) technology in manufacturing industries revolutionized the production process a few decades back. There are some health and safety problems associated with these machine operations, however. The main objectives of the present work is to study the health and safety issues associated with the CNC machines with respect to control and display, specifically to determine the frequency, intensity of discomfort, and its interference in operating different CNC machines as reported by the workers operating them. The postural discomfort associated with CNC machines was studied, and the frequency, intensity of discomfort, and interference of the level of discomfort with the participants' ability to work were recorded and analyzed. The study revealed that 20.5% of the operators reported discomfort 1 or 2 times, 25.4% experienced discomfort 3 to 4 times in a week, 37.7% had discomfort daily, and 16.4% reported discomfort several times a day. Discomfort was reported in all the body parts involved (lower back, neck, upper back, shoulder, and leg), but the highest discomfort scores were associated with the shoulder and arm region. Workers reporting discomfort several times a day also reported high mean discomfort scores. The study established that the frequency and intensity of the discomfort in all body parts is related to the position of the control panel and display. © 2012 Wiley Periodicals, Inc.  相似文献   
7.
Within Australian cities, social and economic inequalities manifest themselves spatially. Perceived neighbourhood disorder and neighbourhood reputation are relevant to considering the ways in which social and economic inequalities translate into place-based inequalities. This article explores the ways in which residents of two socio-economically contrasting urban areas describe and explain neighbourhood disorder and neighbourhood reputation. It draws upon qualitative data from 40 in-depth interviews, in addition to quantitative data from a postal survey. The qualitative findings highlighted how issues of neighbourhood disorder and reputation were intertwined. In both areas, participants sought to portray themselves and their neighbourhoods in positive ways, by attributing responsibility for neighbourhood disorder to people who were unlike themselves, and by highlighting places that were perceived to have worse reputations and higher levels of disorder. The findings are considered in light of Bourdieu's theory of capitals. This article indicates that both neighbourhood disorder and reputation are pathways through which social, economic and health inequities are maintained in urban areas.  相似文献   
8.
The anisotropic effect of a hcp 4He solid matrix on cesium atoms has been proposed as a tool to reveal the parity violating anapole moment of its nucleus. It should also result in splitting the D2 optical excitation line in a way depending on the light polarization. An experimental investigation has been set up using oriented hcp helium crystals in which cesium metal grains are embedded. Atoms are created by laser sputtering from this grains. Optical absorption spectra of the D2 line have been recorded in the temperature range of 1.0 to 1.4 K at liquid/solid coexistence pressure by monitoring the fluorescence on the D2 line at 950 nm. No significant effect of the light polarization has been found, suggesting a statistically isotropic disordered solid environment for the cesium atoms.   相似文献   
9.
The purpose of the research was to assess the diagnostic efficiency of the Primary Care Posttraumatic Stress Disorder Screen (PC-PTSD) and the Posttraumatic Stress Disorder Checklist (PCL) as clinical screening tools for active duty soldiers recently returned from a combat deployment. A secondary goal was to examine the item-level characteristics of both the PC-PTSD and the PCL. A validation study conducted with a sample of 352 service members showed that both the PC-PTSD and PCL had good diagnostic efficiency. The overall diagnostic efficiency assessed by the area under the curve (AUC) was virtually the same for both the PC-PTSD and PCL. The most efficient cutoff values for the PC-PTSD were either 2 or 3 "yes" responses with the latter favoring specificity. For the PCL, the most efficient cutoff values were between 30 and 34, mirroring recommended PCL cutoff values from some studies in primary care settings. The examination of item characteristics suggested a 4-item PCL with an AUC virtually identical to that of the full PCL. Item analyses also identified that the most discriminate item in both scales pertained to symptoms of avoidance. Implications and limitations are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
10.
此研究采用理论计算得出NAD^+的优化结构为环形。NAD^+中有五个较强的O-H和N—H拉伸振动方式。经研究,由于O-H…O和N-H…N氢键的方向不同,发现了NAD^+许多重要形式中的五种多形态。NAD^+呈环状,能与一些分子反应。应用剪切力的概念,讨论了NAD^+多形态的机理。说明了NAD^+的作用机理。NAD^+是一种辅酶,由于形状的改变而成为不规则,即NAD^+呈现多形态。在NAD^+的多形态中,最稳定的结构具有最小的熵。经热力学研究发现,NAD^+的多形态和低熵值归因于反应中的负Gibbs自由能。讨论了NAD^+的多形态对其与食物反应的影响。至于NAD^+的不规则,它取决于NAD^+分子周围分子的本身性质。  相似文献   
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