260 research outputs found

    Scattering theory with finite-gap backgrounds: Transformation operators and characteristic properties of scattering data

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    We develop direct and inverse scattering theory for Jacobi operators (doubly infinite second order difference operators) with steplike coefficients which are asymptotically close to different finite-gap quasi-periodic coefficients on different sides. We give necessary and sufficient conditions for the scattering data in the case of perturbations with finite second (or higher) moment.Comment: 23 page

    Self-reported losses versus actual losses in online gambling: an empirical study

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    Many research findings in the gambling studies field rely on self-report data. A very small body of empirical research also suggests that when using self-report, players report their gambling losses inaccurately. The aim of the present study was to evaluate the differences between objective and subjective gambling spent data by comparing gambler’s actual behavioral tracking data with their self-report data over a 1-month period. A total of 17,742 Norwegian online gamblers were asked to participate in an online survey. Of those surveyed, 1335 gamblers answered questions relating to gambling expenditure that could be compared with their actual gambling behavior. The study found that the estimated loss self-reported by gamblers was correlated with the actual objective loss and that players with higher losses tended to have more difficulty estimating their gambling expenditure (i.e., players who spent more money gambling also appeared to have more trouble estimating their expenses accurately). Overall, the findings demonstrate that caution is warranted when using self-report data relating to amount of money spent gambling in any studies that are totally reliant on self-report data

    The (co-)occurrence of problematic video gaming, substance use, and psychosocial problems in adolescents

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    Aims. The current study explored the nature of problematic (addictive) video gaming and the association with game type, psychosocial health, and substance use. Methods. Data were collected using a paper and pencil survey in the classroom setting. Three samples were aggregated to achieve a total sample of 8478 unique adolescents. Scales included measures of game use, game type, the Video game Addiction Test (VAT), depressive mood, negative self-esteem, loneliness, social anxiety, education performance, and use of cannabis, alcohol and nicotine (smoking). Results. Findings confirmed problematic gaming is most common amongst adolescent gamers who play multiplayer online games. Boys (60%) were more likely to play online games than girls (14%) and problematic gamers were more likely to be boys (5%) than girls (1%). High problematic gamers showed higher scores on depressive mood, loneliness, social anxiety, negative self-esteem, and self-reported lower school performance. Nicotine, alcohol, and cannabis using boys were almost twice more likely to report high PVG than non-users. Conclusions. It appears that online gaming in general is not necessarily associated with problems. However, problematic gamers do seem to play online games more often, and a small subgroup of gamers – specifically boys – showed lower psychosocial functioning and lower grades. Moreover, associations with alcohol, nicotine, and cannabis use are found. It would appear that problematic gaming is an undesirable problem for a small subgroup of gamers. The findings encourage further exploration of the role of psychoactive substance use in problematic gaming

    Operator theory and function theory in Drury-Arveson space and its quotients

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    The Drury-Arveson space Hd2H^2_d, also known as symmetric Fock space or the dd-shift space, is a Hilbert function space that has a natural dd-tuple of operators acting on it, which gives it the structure of a Hilbert module. This survey aims to introduce the Drury-Arveson space, to give a panoramic view of the main operator theoretic and function theoretic aspects of this space, and to describe the universal role that it plays in multivariable operator theory and in Pick interpolation theory.Comment: Final version (to appear in Handbook of Operator Theory); 42 page

    Paired Associative Stimulation of the Auditory System: A Proof-Of-Principle Study

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    Background Paired associative stimulation (PAS) consisting of repeated application of transcranial magnetic stimulation (TMS) pulses and contingent exteroceptive stimuli has been shown to induce neuroplastic effects in the motor and somatosensory system. The objective was to investigate whether the auditory system can be modulated by PAS. Methods Acoustic stimuli (4 kHz) were paired with TMS of the auditory cortex with intervals of either 45 ms (PAS(45 ms)) or 10 ms (PAS(10 ms)). Two-hundred paired stimuli were applied at 0.1 Hz and effects were compared with low frequency repetitive TMS (rTMS) at 0.1 Hz (200 stimuli) and 1 Hz (1000 stimuli) in eleven healthy students. Auditory cortex excitability was measured before and after the interventions by long latency auditory evoked potentials (AEPs) for the tone (4 kHz) used in the pairing, and a control tone (1 kHz) in a within subjects design. Results Amplitudes of the N1-P2 complex were reduced for the 4 kHz tone after both PAS(45 ms) and PAS(10 ms), but not after the 0.1 Hz and 1 Hz rTMS protocols with more pronounced effects for PAS(45 ms). Similar, but less pronounced effects were observed for the 1 kHz control tone. Conclusion These findings indicate that paired associative stimulation may induce tonotopically specific and also tone unspecific human auditory cortex plasticity

    The prevalence of gambling and problematic gambling: a systematic review and meta-analysis

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    Background: Gambling behaviours have become of increased public health interest, but data on prevalence remain scarce. In this study, we aimed to estimate for adults and adolescents the prevalence of any gambling activity, the prevalence of engaging in specific gambling activities, the prevalence of any risk gambling and problematic gambling, and the prevalence of any risk and problematic gambling by gambling activity. Methods: We performed a systematic review and meta-analysis. We systematically searched for peer-reviewed literature (on MEDLINE, Embase, and PsycInfo) and grey literature to identify papers published between Jan 1, 2010, and March 4, 2024. We searched for any gambling, including engagement with individual gambling activities, and problematic gambling data among adults and adolescents. We included papers that reported the prevalence or proportion of a gambling outcome of interest. We excluded papers of non-original data or based on a biased sample. Data were extracted into a bespoke Microsoft Access database, with the Joanna Briggs Institute Critical Appraisal Tool used to identify the risk of bias for each sample. Representative population survey estimates were firstly meta-analysed into country-level prevalence estimates, using metaprop, of any gambling, any risk gambling, problematic gambling, and by gambling activity. Secondly, population-weighted regional-level and global estimates were generated for any gambling, any risk gambling, problematic gambling, and specific gambling activity. This review is registered on PROSPERO (CRD42021251835). Findings: We screened 3692 reports, with 380 representative unique samples, in 68 countries and territories. Overall, the included samples consisted of slightly more men or male individuals, with a mean age of 29·72 years, and most samples identified were from high-income countries. Of these samples, 366 were included in the meta-analysis. Globally, 46·2% (95% CI 41·7–50·8) of adults and 17·9% (14·8–21·2) of adolescents had gambled in the past 12 months. Rates of gambling were higher among men (49·1%; 45·5–52·6) than women (37·4%; 32·0–42·5). Among adults, 8·7% (6·6–11·3) were classified as engaging in any risk gambling, and 1·41% (1·06–1·84) were engaging in problematic gambling. Among adults, rates of problematic gambling were greatest among online casino or slots gambling (15·8%; 10·7–21·6). There were few data reported on any risk and problematic gambling among adolescent samples. Interpretation: Existing evidence suggests that gambling is prevalent globally, that a substantial proportion of the population engage in problematic gambling, and that rates of problematic gambling are greatest among those gambling on online formats. Given the growth of the online gambling industry and the association between gambling and a range of public health harms, governments need to give greater attention to the strict regulation and monitoring of gambling globally

    Paclitaxel and concomitant radiotherapy in high-risk endometrial cancer patients: preliminary findings

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    BACKGROUND: There is still much debate about the best adjuvant therapy after surgery for endometrial cancer (EC) and there are no current guidelines. Radiotherapy (RT) alone does not seem to improve overall survival. We investigated whether concomitant Paclitaxel (P) and RT gave better clinical results. METHODS: Twenty-three patients with high-risk EC (stage IIB, IIIA, IIIC or IC G3 without lymphadenectomy or with aneuploid tumor) underwent primary surgery and were then referred for adjuvant therapy. P was given at a dose of 60 mg/m2 once weekly for five weeks during RT, which consisted of a total radiation dose of 50.4 Gy. Three further weekly cycles of P at a dose of 80 mg/m2 were given at the end of RT. Overall survival and disease-free survival were calculated from the time of surgery. Patterns of failure were recorded by the sites of failure. RESULTS: A total of 157 cycles of P were administered both during radiotherapy and consolidation chemotherapy. Relapses occurred in five patients (21.7%). Median time to recurrence was 18.6 months (range 3–28). Survival rate for all the patients was 78.2%. Overall survival for the patients who completed chemo-radiation was of 81%. In this group median time to recurrence was 19.2 months (range 3–28). All recurrences were outside the radiation field. Mortality rate was 14.2%. CONCLUSION: This small series demonstrates pelvic radiotherapy in combination with weakly P followed by three consolidation chemotherapy cycles as an effective combined approach in high risk endometrial carcinoma patients

    Lower-risk gambling limits : linked analyses across eight countries

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    The Lower Risk Gambling Guidelines project was funded by a grant to the Canadian Centre on Substance Use and Addiction from Mise sur Tois a now defunct, independent, not-for-profit organization that received an annual contribution to conduct safer gambling initiatives from the Quebec crown corporation in charge of conducting and managing gambling in the province of Quebec, Canada. Publisher Copyright: © 2022 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.A common public health initiative in many jurisdictions is provision of advice to people to limit gambling to reduce the risk of gambling-related harm. The purpose of this study is to use consistent methodology with existing population-based prevalence surveys of gambling and related harms from different countries to identify quantitative limits for lower risk gambling. Risk curve analyses were conducted with eleven high quality data sets from eight Western countries. Gambling indicators were monthly expenditure, percentage of income spent on gambling, monthly frequency, and number of different types of gambling. Harm indicators included financial, emotional, health, and relationship impacts. Contributing data sets produced limit ranges for each gambling indicator and each harm indicator, which were compared. Gender differences in limit ranges were minor. Modal analysis, an assessment of the mean of the upper and lower range limits, indicated that the risk of harm increases if an individual gambles at these levels or greater: 60to60 to 120 CAD monthly, five to eight times monthly, spends more than 1 to 3% of gross monthly income or plays three to four different gambling types. This study provides further evidence that lower-risk gambling guidelines can be based upon empirically derived limits.Peer reviewe
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