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41.
Lopes MG de Gouveia Vilela RA de Almeida IM Mioto OL Takahashi MA Perin FO 《Work (Reading, Mass.)》2012,41(Z1):3148-3154
In 2010, an accident occurred in Americana-SP, Brazil, involving two trains and one bus on a Grade Crossing, when 10 people died and 17 were injured including workers. This paper aims to analyze the accident using the Model of Analysis and Prevention of Work Accidents (MAPA). The method provides observation of work, interviews and analysis of documents to understand precedents of the event in the following stages: to understand the usual work from the involved people, the changes occurred in the system, the operation of barriers, managerial and organizational aspects. By the end, measures are suggested to avoid new occurrences. The accident took place at night in a site with insufficient lighting. The working conditions of bus drivers, train operators and watchmen are inadequate. There were only symbolic barriers (visual and acoustic signals) triggered manually by watchman upon train operator radio communication. The fragility of the barrier system associated to poor lighting and short time to trigger the signaling seem to play a critical role in the event. Contrary to the official report which resulted in guilt of the bus driver, the conclusion of the paper emphasizes the fragility of the safety system and the need of level crossing reproject. 相似文献
42.
In Japan, the ratio of never-married men to married men has risen rapidly since the second half of the 1980s. In this paper,
we focus on the disruption of the gender balance, and on the effect that this and education level have on marriage behaviour.
We confirmed that the rise in the population of never-married men has a negative influence on the probability that men will
marry; however, it does not affect women’s behaviour. The effects of education in relation to the probability of marrying
are positive for men, and negative for women. Generally, a low educational background is associated with low income and our
results predict that elderly single men will tend to be of low socio-economic status. The present social security system is
substantially reliant on the assumption that most single older people have families. An increase in aged single men in recent
years means a new social security system is required. 相似文献
43.
In phase I trials, the main goal is to identify a maximum tolerated dose under an assumption of monotonicity in dose–response relationships. On the other hand, such monotonicity is no longer applied to biologic agents because a different mode of action from that of cytotoxic agents potentially draws unimodal or flat dose–efficacy curves. Therefore, biologic agents require an optimal dose that provides a sufficient efficacy rate under an acceptable toxicity rate instead of a maximum tolerated dose. Many trials incorporate both toxicity and efficacy data, and drugs with a variety of modes of actions are increasingly being developed; thus, optimal dose estimation designs have been receiving increased attention. Although numerous authors have introduced parametric model-based designs, it is not always appropriate to apply strong assumptions in dose–response relationships. We propose a new design based on a Bayesian optimization framework for identifying optimal doses for biologic agents in phase I/II trials. Our proposed design models dose–response relationships via nonparametric models utilizing a Gaussian process prior, and the uncertainty of estimates is considered in the dose selection process. We compared the operating characteristics of our proposed design against those of three other designs through simulation studies. These include an expansion of Bayesian optimal interval design, the parametric model-based EffTox design, and the isotonic design. In simulations, our proposed design performed well and provided results that were more stable than those from the other designs, in terms of the accuracy of optimal dose estimations and the percentage of correct recommendations. 相似文献
44.
This study examined the influence of the individual and social background in predicting the rearrest of 1124 juveniles who were first brought into the juvenile detention center in a midsized county in California. Independent variables include demographic characteristics, first offense type, gang affiliation, usage of drug, and family characteristics. Using cross-validation to choose an appropriate machine learning model for predicting rearrest, this study identified that the most important predictors of subsequent arrest are age at first arrest, drug usage, gang affiliation, and family with government assistance. Despite the fact that blacks are overrepresented in the juvenile detention population, race was not a significant predictor for rearrest. Future research would continue to explore the utilization of machine learning adding nontraditional variables to enhance the prediction of recidivism. 相似文献
45.
46.
Hideaki Takeuchi Ryosaku Kawada Kosuke Tsurumi Naoto Yokoyama Ariyoshi Takemura Takuro Murao Toshiya Murai Hidehiko Takahashi 《Journal of gambling studies / co-sponsored by the National Council on Problem Gambling and Institute for the Study of Gambling and Commercial Gaming》2016,32(4):1143-1154
Pathological gambling (PG) is characterized by continual repeated gambling behavior despite negative consequences. PG is considered to be a disorder of altered decision-making under risk, and behavioral economics tools were utilized by studies on decision-making under risk. At the same time, PG was suggested to be a heterogeneous disorder in terms of personality traits as well as risk attitude. We aimed to examine the heterogeneity of PG in terms of loss aversion, which means that a loss is subjectively felt to be larger than the same amount of gain. Thirty-one male PG subjects and 26 male healthy control (HC) subjects underwent a behavioral economics task for estimation of loss aversion and personality traits assessment. Although loss aversion in PG subjects was not significantly different from that in HC subjects, distributions of loss aversion differed between PG and HC subjects. HC subjects were uniformly classified into three levels (low, middle, high) of loss aversion, whereas PG subjects were mostly classified into the two extremes, and few PG subjects were classified into the middle range. PG subjects with low and high loss aversion showed a significant difference in anxiety, excitement-seeking and craving intensity. Our study suggested that PG was a heterogeneous disorder in terms of loss aversion. This result might be useful for understanding cognitive and neurobiological mechanisms and the establishment of treatment strategies for PG. 相似文献
47.
For a sum of not identic ally but independently distributed discrete random variables, its higher order large-deviation approximation in given. They are compared with the normal and Edge-worth type approximations in various cases. Consequently, the large-deviation approximations give sufficiently accurate results. 相似文献
48.
Izumi Washitani Yasushi Okayama Keiko Sato Hitomi Takahashi Takayuki Ohgushi 《Researches on Population Ecology》1996,38(2):249-256
Antagonistic biological interactions with flower consumers and pathogens may influence reproductive success of flowering plants,
affecting population dynamics and natural selection for floral traits. However, ecological and evolutionary consequences of
the interactions may depend on both spatial and temporal patterns of the interactions. In a forest metapopulation ofPrimula sieboldii E. Morren, an endangered clonal plant species, we measured between-subpopulation patterns of seed sets and interactions with
an influential flower consumer, a rove beetle,Eusphalerum bosatsu Watanabe, and a specific smut fungal pathogen,Urocystis tranzschelina (Lavrov) Zundel (Ustilaginales), for three years. Mean female fertility (seed set per flower) for individual subpopulations
fluctuated moderately among years but was highly variable within each year among the five subpopulations studied. In two subpopulations,
the impact ofEusphalerum beetle, was sufficiently large to result in almost complete failure in seed production over eight years including the three
study and five previous preliminary observation years. In the two other subpopulations, seed set failure was caused by infection
by the smut fungus. Infected capsules which constitute 10–30% of the capsules produced in the subpopulations were filled with
ustilospores instead of seeds. In the subpopulation that escaped flower damage byEusphalerum beetles and smut fungal infection, seed sets of both pin and thrum flowers were much higher than in the other subpopulations.
The spatial restriction of individual antagonistic agents to a part of subpopulations suggest that dispersal of the agents,
as well as the mode of spatial subdivision of the plant population would be important for determining the overall effects
of antagonistic interactions on plant performances at the metapopulation level. 相似文献
49.
Generation carryover of a fraction of population members as an animal adaptation to unstable environmental conditions 总被引:3,自引:0,他引:3
Fumiki Takahashi 《Researches on Population Ecology》1977,18(2):235-242
Summary A heterogeneous life cycle of individuals in a population was examined on its adaptive significance to an unstable environmental
condition. The trend of population growth was simulated by a simple mathematical model in which a part of population in a
certain generation was carried over to the next generation without participating in the reproduction.
With the increase of the rate of carryover of individuals to the next generation the population fluctuation tended to be stabilized.
A minute fraction of population is carried over, the effect is very large to prevent the population decline at a sequence
of adverse environmental conditions. The population level increased greatly depending upon the extent of environmental change
as far as the rate of carryover took an intermediate value. The optimum proportion of members to be carried over to the next
generation was determined by the extent of environmental change and its frequency of occurrence.
Contribution from the Entomological Laboratory, College of Agriculture, Kyoto University, No. 451. 相似文献
50.