340 research outputs found

    Online Video Game Addiction: Exploring a New Phenomenon

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    Over a period of thirty years, video games have evolved from Pac Man to photorealistic, massively populated, three-dimensional environments. Adolescents become involved with online virtual communities (tribes, guilds, groups) and play games on a daily basis with people they have never seen in ‘real’ life. Large online games provide a virtual environment in which they have fun and can freely experiment with different identities, speak other languages, and form new social connections at the same time. Nowadays, games have developed beyond simple concepts such as ‘eat-the-yellow-dots’ in Pac Man. Gaming now includes sophisticated persistent virtual worlds (World of Warcraft, Lord of the Rings Online, Guild Wars), competitive team-based online shooting games (Counterstrike, Team Fortress 2), and multiuser real-time strategy games (Starcraft 2, Warcraft 3). These changes are largely driven by the rapid developments in computing power and internet access, as well as by the declining costs of consumer electronics. As a result of increased availability, more people are playing games; however, some individuals seem to be playing more as well. A 2008 press release by the market research group NPD states that: “…of the 174 million gamers who personally play games on PC/Mac or video game systems, three percent are Extreme Gamers” (NPD, 2008). Extreme gamers play an average of 45 hours per week. A press release by the same firm two years later stated that this percentage had increased. In 2010 the NPD group reported that the group of extreme gamers had grown to four percent, emphasizing that “…extreme gamers spend two full days per week playing video games” (NPD, 2010)

    Inhibin reduces spermatogonial numbers in testes of adult mice and chinese hamsters

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    Bovine follicular fluid (bFF) injected ip in mice during 2 days (65,000 U inhibin/day, 1 U inhibin the activity in 1 /Îźg bFF protein) caused a significant decrease in the numbers of A4, intermediate (In), and B spermatogonia to 91%,74%, and 67% of the control values, respectively. The numbers of undifferentiated spermatogonia remained unchanged. These injections suppressed peripheral FSH levels to 6% of the control values, suggesting that FSH might be the modulator of the effects on spermatogenesis. However, in the Chinese hamster, intratesticular injections of bFF during 4 days (6500 U inhibin/day into one testis) also caused a significant decrease in the numbers of A3, In, B1, and B2 spermatogonia to 86%, 61%, 55%, and 94% of the control values, respectively. Similarly, treatment with a partially purified inhibin preparation from rat Sertoli cell-conditioned medium (rSCCM) during 4 days (Mono Q fraction; 1512 U inhibin/day; 37.8 Îźg protein) caused a significant decrease in the numbers of A3, In, B1, and B2 spermatogonia to 90%, 87%, 66%, and 93% of the control values, respectively. Treatment with a highly purified inhibin preparation from rSCCM during 4 days (30K inhibin; 750 U inhibin/day; 100 ng protein) significantly decreased the numbers of In and B1 spermatogonia to, respectively, 87% and 91% of the control values. These effects were limited to the testis into which the material was injected; the contralateral testis or testes injected with control fluid always showed normal numbers of spermatogonia. This implies that the effects on the seminiferous epithelium are not FSH mediated. Intratesticular injections of bFF or pure inhibin did not affect the number of undifferentiated spermatogonia. However, the Mono Q fraction caused a significant increase in the numbers of undifferentiated spermatogonia in stages IV-VII of the cycle, suggesting the presence of a mitogenic factor for undifferentiated spermatogonia in rSCCM which is not present or is counteracted in bFF. The results suggest that inhibin may have a role in the regulation of spermatogonial development in the adult animal

    Resolving discharge parameters from atomic oxygen emission

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    A method is proposed to spatially resolve discharge parameters from experimental measurements of emission intensity and 1D numerical simulations including an O atom collisional-radiative model. The method can be used for different plasmas and conditions. Here, contracted microwave discharges for CO2 conversion are studied at intermediate to high pressures (100–300 mbar). Radial profiles of electron density (ne) are used as input in the model and corrected to successfully simulate the measured Gaussian profiles of emission intensity of the 777 nm transition (I777). As a result, radially-resolved parameters inaccessible in experiments, such as ne, power density (Pabs), electron temperature (Te), electric field and reaction rates, are numerically-obtained for several conditions. ne and Pabs approximately follow Gaussian profiles that are broader than that of I777. For pressures below 150 mbar, the difference in full width at half maximum is typically a factor 1.6. This consists in a phenomenon of optical contraction, which is due to concave profiles of O molar fraction and Te. The implications of the simulated profiles on the study of plasmas for CO2 conversion are discussed and it is shown that these profiles allow to explain high reactor performances at low pressures

    Behavioral design in video games: a roadmap for ethical and responsible games that contribute to long-term consumer health and well-being

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    Commissioned by the Dutch Ministry of the Interior and Kingdom RelationsEffective Protection of Fundamental Rights in a pluralist worl

    “Don't gamble with children's rights”: how behavioral design impacts the right of children to a playful and healthy game environment

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    Gaming is an important pastime for young people to relax, socialize and have fun, but also to be challenged, show creativity and work together to achieve goals. The design of games can have an impact on their behavior. With the changing revenue models of games, we see that game design is increasingly taking forms that do not always have a positive impact on children and may interfere with, or even violate, children's rights. This article examines how evolving revenue models of games impact user's behavior via game design. Behavioral design in games thus raises questions about children's rights to play and recreation, to health, to protection from economic exploitation and to data protection.Effective Protection of Fundamental Rights in a pluralist worl

    A particle-based model for endothelial cell migration under flow conditions

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    Endothelial cells (ECs) play a major role in the healing process following angioplasty to inhibit excessive neointima. This makes the process of EC healing after injury, in particular EC migration in a stented vessel, important for recovery of normal vessel function. In that context, we present a novel particle-based model of EC migration and validate it against in vitro experimental data. We have developed a particle-based model of EC migration under flow conditions in an in vitro vessel with obstacles. Cell movement in the model is a combination of random walks and directed movement along the local flow velocity vector. For model calibration, a set of experimental data for cell migration in a similarly shaped channel has been used. We have calibrated the model for a baseline case of a channel with no obstacles and then applied it to the case of a channel with ridges on the bottom surface, representative of stent strut geometry. We were able to closely reproduce the cell migration speed and angular distribution of their movement relative to the flow direction reported in vitro. The model also reproduces qualitative aspects of EC migration, such as entrapment of cells downstream from the flow-disturbing ridge. The model has the potential, after more extensive in vitro validation, to study the effect of variation in strut spacing and shape, through modification of the local flow, on EC migration. The results of this study support the hypothesis that EC migration is strongly affected by the direction and magnitude of local wall shear stress

    Video gaming in a hyperconnected world: A cross-sectional study of heavy gaming, problematic gaming symptoms, and online socializing in adolescents

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    Aims Examining online social interactions along with patterns of video gaming behaviors and game addiction symptoms has the potential to enrich our understanding of disorders related to excessive video game play. Methods We performed latent class analysis in a sample of 9733 adolescents based on heavy use of games, social networking and instant messaging, and game addiction symptoms. We used latent class regression to determine associations between classes, psychosocial well-being and friendship quality. Results We identified two types of heavy gaming classes that differed in probability of online social interaction. Classes with more online social interaction reported fewer problematic gaming symptoms than those with less online social interaction. Most adolescents estimated to be in heavy gaming classes had more depressive symptoms than normative classes. Male non-social gamers had more social anxiety. Female social gamers had less social anxiety and loneliness, but lower self-esteem. Friendship quality attenuated depression in some male social gamers, but strengthened associations with loneliness in some male non-social gamers. Conclusions In adolescents, symptoms of video game addiction depend not only on video game play but also on concurrent levels of online communication, and those who are very socially active online report fewer symptoms of game addiction

    Failing beta-cell adaptation in South Asian families with a high risk of type 2 diabetes

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    We performed an extended oral glucose tolerance test (OGTT) to investigate the relationship between early and late beta-cell response and type 2 diabetes (T2D) in families of South Asian origin and indigenous Dutch, burdened by T2D. Based on the OGTT, 22 individuals were normoglycemic, 12 glucose intolerant and 23 had T2D in the South Asian families; these numbers were 34, 12 and 18 in the Caucasian families, respectively. The OGTT had 11 blood samplings in 3.5 h for glucose, insulin and C-peptide measurements. Through early and late insulin secretion rate (ISR), the above basal glucose area-under-the-curve after glucose load (glucose disposal) and insulin sensitivity index (ISI), we obtained early and late disposition indices (DI). South Asians on average had lower ISI than Caucasians (3.8 ¹ 2.9 vs. 6.5 ¹ 4.7, respectively, P < 0.001), with rapid decline of their early and late DI between normal glucose tolerance versus impaired fasting glucose/impaired glucose tolerance (late DI; P < 0.0001). Adjusted for ISI, age, gender and waist-to-hip ratio, early ISR was significantly associated with glucose disposal in South Asians (β = 0.55[0.186; 0.920]), but not in Caucasians (β = 0.09[-0.257; 0.441]). Similarly, early ISR was strongly associated with late ISR (β = 0.71[0.291; 1.123]; R2 = 45.5 %) in South Asians, but not in Caucasians (β = 0.27[-0.035; 0.576]; R2 = 17.4 %), with significant interaction between ethnicity and early ISR (β = 0.341[0.018; 0.664]). Ordinal regression analyses confirmed that all South Asian OGTT subgroups were homogenously resistant to insulin and solely predicted by early ISR (β = -0.782[-1.922; 0.359], β = -0.020[-0.037; -0.002], respectively), while in Caucasian families both ISI and early ISR were related to glucose tolerance state (β = -0.603[-1.105; -0.101], β = -0.066[-0.105; -0.027], respectively). In South Asian individuals, rapid beta-cell deterioration might occur under insulin resistant conditions. As their early insulin response correlates strongly with both glucose disposal and late insulin response, alterations in beta-cell dynamics may give an explanation to their extreme early onset of T2D, although larger prospective studies are required
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