Interaction between Macroinvertebrate Abundance and Habitat Use by Diving Ducks during Winter on Northeastern Lake Ontario

Although numbers of buffleheads (Bucephala albeola), common goldeneyes (Bucephala clangula) and long-tailed ducks (Clangula hyemalis) over-wintering on Lake Ontario have increased substantially over the past two decades, factors influencing habitat use and the potential for competition have not been investigated. The purpose of this study was to determine the relationship between prey availability and community structure of diving ducks during winter on northeastern Lake Ontario. Benthic and nektonic samples collected during fall, winter, and spring 2002–2004 indicated that macroinvertebrate numbers differed by location but generally did not decline throughout winter. Large accumulations of macroinvertebrates, apparently moved by wave action and currents, were documented in nearshore areas. Surveys showed that diving ducks congregated in mixed species flocks within areas of higher food abundance. Mixed species flocks were common in nearshore areas, likely because energydense foods (Amphipoda and Chironomidae) were abundant in the narrow zone of shallow water, close to shore. Although macroinvertebrate numbers likely affected habitat use by diving ducks, birds did not greatly reduce abundance of macroinvertebrates. It is unlikely that exploitative competition was occurring and interference competition appeared below threshold levels that would cause species to spatially segregate. Overall, our results suggest that food availability is not a limiting factor for buffleheads, common goldeneyes, or long-tailed ducks wintering on northeastern Lake Ontario.     

Ergonomic risk factors for the wrists of hairdressers

This study utilized a portable data logger to measure the wrist angles and forearm flexor and extensor electromyography (EMG) of 21 hairstylists. The hairstylists were divided into two groups, one with 11 barbers (9 males and 2 females) specializing in men's hairdressing, and one with 10 hairdressers (2 males and 8 females) specializing in women's hairdressing. The standard haircut task was divided into three subtasks: hair cutting, washing and blow-drying. The mechanical exposures of the overall task and subtasks were quantified to compare how subtasks, occupational groups, and gender groups differ. Experimental results show that the average time to finish a woman's haircut (51.4 min) is significantly longer than that for a man's haircut (35.6 min) (p < 0.005). Female hairstylists had significantly greater EMG activity than male hairstylists did (p < 0.001). The non-dominant hands of hairdressers have significantly higher overall wrist velocity than those of barbers (p < 0.005). Analytical results suggest that the relatively higher force exertion and wrist velocity of female hairstylists combined with prolonged exposure may account for the higher rate of hand/wrist pain in female hairdressers than in male barbers.     

Team performance modeling for HRA in dynamic situations

This paper proposes a team behavior network model that can simulate and analyze response of an operator team to an incident in a dynamic and context-sensitive situation. The model is composed of four sub-models, which describe the context of team performance. They are task model, event model, team model and human–machine interface model. Each operator demonstrates aspects of his/her specific cognitive behavior and interacts with other operators and the environment in order to deal with an incident. Individual human factors, which determine the basis of communication and interaction between individuals, and cognitive process of an operator, such as information acquisition, state-recognition, decision-making and action execution during development of an event scenario are modeled. A case of feed and bleed operation in pressurized water reactor under an emergency situation was studied and the result was compared with an experiment to check the validity of the proposed model.     

Mundane remembering.

Reviews the book, Remembering Reconsidered: Ecological and Traditional Approaches to the Study of Memory by Ulric Neisser and Eugene Winograd (see record 1988-98127-000). This volume is the second in a series known as The Emory Symposia in Cognition. The first volume addressed the question of "ecological and intellectual factors in categorization" and this second collection of papers pursues the ecological theme into the challenging realm of memory. As often happens with published symposia, the collection of chapters is greatly enlivened by the integrative commentary of thoughtful critics. In this volume this function is particularly well served with separate contributions by Neisser, Winograd, McCauley, Fivush, and by Rubin. My only regret is that none of them managed to bring order into the chaotic use of the term functional as it appears in various parts of the symposium. These commentaries add to the primary contributions in a way that results in a volume that is thematically more integrated than many such symposium collections. None of the contributions digs deeply into the real issues underlying the relationship between naturalistic and laboratory studies, but most of them demonstrate by way of example that the two approaches can serve complementary roles and a common goal. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Parametric quadratic programming method for elastic contact fracture analysis

A solution procedure for elastic contact fracture mechanics has been proposed in this paper. The procedure is based on the quadratic programming and finite element method (FEM). In this paper, parametric quadratic programming method for two-dimensional contact mechanics analysis is applied to the crack problems involving the crack surfaces in frictional contact. Based on a linear complementary contact condition, the parametric variational principle and FEM, a linear complementary method is extended to analyze contact fracture mechanics. The near-tip fields are properly modeled in the analysis using special crack tip elements with quarter-point nodes. Stress intensity factor solutions are presented for some frictional contact fracture problems and are compared with known results where available.     

Differentiating stages of smoking intensity among adolescents: Stage-specific psychological and social influences.

Researchers' understanding of the impact of sociocultural and psychological factors on the various stages of adolescent smoking update is limited. Using national data, the authors examined transitions across smoking stages among adolescents (N=20,747) as a function of interpersonal, familial, and peer domains. Peer smoking was particularly influential on differentiating regular smoking, whereas alcohol use was most influential on earlier smoking. Although significant, depression and delinquency were attenuated in the context of other variables. Higher school grade was more likely to differentiate regular smoking from earlier smoking stages, whereas African American ethnicity and connectedness to school and family were protective of smoking initiation. Results lend support for an interactional approach to adolescent smoking, with implications for stage-matched prevention and intervention applications. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Why We Sing the Blues: The Relation Between Self-Reflective Rumination, Mood, and Creativity.

Past research has shown that creative behavior is associated with a higher risk for depression. The authors hypothesized that a 3rd underlying factor, namely, self-reflective rumination, may explain the connection. This hypothesis was examined in a sample of 99 undergraduate college students, using path analysis. The authors found that self-reported past depressive symptomatology was linked to increased self-reflective rumination. Rumination, in turn, was related to current symptomatology and to self-rated creative interests and objectively measured creative fluency, originality, and elaboration. No direct link existed between currently depressed mood and either creative interest or creative behavior. These results suggest that the association between depression and creativity is solely the result of rumination. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

影响聚氯乙烯树脂颗粒形态的因素

介绍了搅拌、分散剂、转化率、聚合温度水油比对聚氯乙烯树脂颗粒形态的影响,提出了保证合适的树脂质量及形态的控制工艺条件和参数。     

浅论可液化地基地震液化判定计算的改进

从液化判定计算的原理及液化机理的讨论出发，通过对地形地貌、地质构造和可液化土层的结构等地质因素的地震反应机理及其对地震液化影响的分析，阐述了对现行规范（ＧＢＪ１１－８９）中的地震液化程度判定结果的修正建议     

Estimation of exposure to food packaging materials. 3: Development of consumption factors and food-type distribution factors from data collected on Irish children

There are many initiatives in Europe trying to refine the exposure assessment for food packaging migrants. In the USA, the US Food and Drug Administration (US FDA) uses food consumption and food-type distribution factors to aid the exposure assessment process and generate more realistic estimates of exposure. The present study developed food-consumption factors and food-type distribution factors for Irish children aged 5-12 years from data collected as part of a National Children's Food Survey (NCFS) completed in Ireland in 2003-04, combined with data from the 2003-05 Irish Food Packaging Database and from literature data on surface area-to-weight ratios for food packaging. Consumption factors are defined as the fraction of a person's diet likely to contact a specific food-contact material, while food-type distribution factors reflect the fraction of all food contacting each material that is aqueous, acidic, alcoholic or fatty. In this study, it was found that 'total plastics' had the highest consumption factor of 0.83, while 'total paper and board' had a factor of 0.13 and 'total metal and alloys' had a factor of 0.06. Although it is tentative to compare the US FDA factors with the factors derived in the current study, as the US FDA data are for the total US population, the consumption factor for 'total plastics' in the present study (0.83) was similar to that used by the US FDA (0.79). However, a large difference existed for the consumption factor for 'total metal and alloys' in the Irish data (0.06) and the US FDA data (0.2). In terms of the type of materials used for foods, glass was used mainly for acidic foods (0.67), while plastic was uniformly used for all food types. The food-contact area for plastic packaging for all foods consumed by children was 10.67 dm²/child day^-1, which is slightly lower than the proposed value for the average European consumer of 12.4 dm²/person day^-1. However, this should be expected, as children do not consume as much food as adults. When scenario exposure estimates were made, it was found that when using European Union assumptions, estimates were much larger than when using consumption factors and food-type distribution factors in the exposure assessment, even when conservative assumptions were employed for the consumption factor. This study highlights the potential use of consumption factors and food-type distribution factors in the refinement of the exposure assessment process and how these factors can be calculated using data collected as part of a national food survey.