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241.
Bráulio M. Veloso Thais R. Correa Marcos O. Prates Gabriel F. Oliveira Andréa I. Tavares 《Statistics and Computing》2017,27(4):1099-1110
Crime or disease surveillance commonly rely in space-time clustering methods to identify emerging patterns. The goal is to detect spatial-temporal clusters as soon as possible after its occurrence and to control the rate of false alarms. With this in mind, a spatio-temporal multiple cluster detection method was developed as an extension of a previous proposal based on a spatial version of the Shiryaev–Roberts statistic. Besides the capability of multiple cluster detection, the method have less input parameter than the previous proposal making its use more intuitive to practitioners. To evaluate the new methodology a simulation study is performed in several scenarios and enlighten many advantages of the proposed method. Finally, we present a case study to a crime data-set in Belo Horizonte, Brazil. 相似文献
242.
Control‐based imputation for sensitivity analyses in informative censoring for recurrent event data
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Fei Gao Guanghan F. Liu Donglin Zeng Lei Xu Bridget Lin Guoqing Diao Gregory Golm Joseph F. Heyse Joseph G. Ibrahim 《Pharmaceutical statistics》2017,16(6):424-432
In clinical trials, missing data commonly arise through nonadherence to the randomized treatment or to study procedure. For trials in which recurrent event endpoints are of interests, conventional analyses using the proportional intensity model or the count model assume that the data are missing at random, which cannot be tested using the observed data alone. Thus, sensitivity analyses are recommended. We implement the control‐based multiple imputation as sensitivity analyses for the recurrent event data. We model the recurrent event using a piecewise exponential proportional intensity model with frailty and sample the parameters from the posterior distribution. We impute the number of events after dropped out and correct the variance estimation using a bootstrap procedure. We apply the method to an application of sitagliptin study. 相似文献
243.
Patient heterogeneity may complicate dose‐finding in phase 1 clinical trials if the dose‐toxicity curves differ between subgroups. Conducting separate trials within subgroups may lead to infeasibly small sample sizes in subgroups having low prevalence. Alternatively,it is not obvious how to conduct a single trial while accounting for heterogeneity. To address this problem,we consider a generalization of the continual reassessment method on the basis of a hierarchical Bayesian dose‐toxicity model that borrows strength between subgroups under the assumption that the subgroups are exchangeable. We evaluate a design using this model that includes subgroup‐specific dose selection and safety rules. A simulation study is presented that includes comparison of this method to 3 alternative approaches,on the basis of nonhierarchical models,that make different types of assumptions about within‐subgroup dose‐toxicity curves. The simulations show that the hierarchical model‐based method is recommended in settings where the dose‐toxicity curves are exchangeable between subgroups. We present practical guidelines for application and provide computer programs for trial simulation and conduct. 相似文献
244.
245.
T.V. Ignatova V.A. Ivichev F.F. Khusnoiarov 《Russian social science review : a journal of translations》2017,58(1):69-73
It is impossible to imagine the contemporary Internet without social media. Government agents, commercial, state, and social organizations, the opposition, and other citizens use social media as a giant turbine. Unfortunately, this turbine can also be used to spread disinformation as well as hostile propaganda on a mass scale. In this article we show how vulnerable social media are to infiltration by botnets with the goal of launching information attacks. 相似文献
246.
Mariann Olsson Tina Lundberg Carl Johan Fürst Joakim Öhlén Ulla Forinder 《Journal of social work in end-of-life & palliative care》2017,13(1):44-60
Despite the evidence of unmet support needs among young people who have lost a parent to cancer, only a few support group initiatives have been reported. This observational prospective study explored the psychosocial well-being of young people who participated in support groups at a Swedish specialist palliative care setting. On three occasions, 29 participants, aged 16–28 years, answered questionnaires covering characteristics of the participants, circumstances of the losses, psychosocial well-being of the young people, and their own assessment of the support groups. The support groups attracted mostly young women who were often unprepared for the loss. The living arrangements differed between younger and older participants; however, the loss-related variables did not differ. Significant positive changes were found regarding a sense of meaning in their future life and life satisfaction. The helpfulness of the group was assessed as high/very high and the group brought a valuable fellowship with others in a similar situation. Universality and beneficial interactions were reported and strengthened psychosocial well-being developed over time. This change, according to the young people themselves, may be attributed to the group support. The findings are useful for planning interventions to support young people in bereavement in order to enhance their psychosocial well-being. 相似文献
247.
C. De Ruysscher C. Claes T. Lee F. Cui J. Van Loon J. De Maeyer R. Schalock 《Voluntas: International Journal of Voluntary and Nonprofit Organizations》2017,28(6):2530-2545
Currently, disabilities organizations are increasingly being challenged by the requirement for individualized service, expectations to show personal outcomes, and the need to base their services on evidence-based practices. Social entrepreneurship (SE) is being put forward as an innovative approach for dealing with these challenges. This article presents a systems approach to SE based on a program logic model. This model identifies the input factors (a strong social vision, exploiting opportunities, maximizing resources), throughput strategies (entrepreneurial orientation, critical thinking skills, networking, capacity building), and outcome components (improving people’s lives, community-building, improving society) of SE at the micro, meso, and macro level. Also, the importance of planning for contextual changes as a social entrepreneur is discussed. The article concludes with presenting three inspiring practices regarding SE in the field of disabilities organizations. 相似文献
248.
John W. Welte Grace M. Barnes Marie-Cecile O. Tidwell William F. Wieczorek 《Journal of gambling studies / co-sponsored by the National Council on Problem Gambling and Institute for the Study of Gambling and Commercial Gaming》2017,33(2):327-342
In this article we examine data from a national U.S. adult survey of gambling to determine correlates of problem gambling and discuss them in light of theories of the etiology of problem gambling. These include theories that focus on personality traits, irrational beliefs, anti-social tendencies, neighborhood influences and availability of gambling. Results show that males, persons in the 31–40 age range, blacks, and the least educated had the highest average problem gambling symptoms. Adults who lived in disadvantaged neighborhoods also had the most problem gambling symptoms. Those who attended religious services most often had the fewest problem gambling symptoms, regardless of religious denomination. Respondents who reported that it was most convenient for them to gamble had the highest average problem gambling symptoms, compared to those for whom gambling was less convenient. Likewise, adults with the personality traits of impulsiveness and depression had more problem gambling symptoms than those less impulsive or depressed. Respondents who had friends who approve of gambling had more problem gambling symptoms than those whose friends did not approve of gambling. The results for the demographic variables as well as for impulsiveness and religious attendance are consistent with an anti-social/impulsivist pathway to problem gambling. The results for depression are consistent with an emotionally vulnerable pathway to problem gambling. 相似文献
249.
Mark E. Mitchell Stephen F. Matter Richard D. Durtsche Ishi Buffam 《Urban Ecosystems》2017,20(5):1121-1133
Green roofs are emerging engineered ecosystems that provide multiple benefits, but many are constructed with nutrient-rich substrate and have been found to leach out high levels of phosphorus (P) in runoff. It is unclear, however, how long green roofs act as sources of P or what mechanisms are responsible for these net losses. We measured P concentrations in runoff water over 4 years from a 1–5 year old extensive green roof in Cincinnati, OH, USA, produced a model to predict runoff P levels into the future, and validated predictions using runoff from 2 nearby extensive green roofs. P concentrations in runoff from the focal green roof were on par with heavily fertilized agroecosystems and displayed strong seasonal dynamics and a rapid decline over the 4-year study. Runoff measurements and changes in substrate P content over a 2-year period were used to estimate a mass balance for green roof P. P loss from the substrate was substantial (4.55 ± 2.3 g P/m2/yr), but only a small portion of the loss was attributable to leaching of P in runoff (0.19–0.65 g P/m2/yr). Missing P may be attributed to a combination of plant uptake and altered P form and binding strength, but further research is needed to precisely identify the mechanisms of P depletion. Our results also suggest that these and similar extensive green roofs are likely to act as environmentally significant sources of P for 10 or more years following roof installation, highlighting the need for reductions in initial substrate P content. 相似文献
250.