Simulations of complex particle transport in heterogeneous active liquids

Thermal-fluctuation and external force-induced motion of particles provide mechanical and rheological information for viscoelastic liquids and soft solids. Although particle tracking is well-developed, analysis of particle trajectories in active heterogeneous materials, such as living cells, is usually not simple or straightforward. These trajectories are sometimes composed of several concurrent processes occurring simultaneously or episodically in a complex fluid. Here, we introduce simulations that generate 2-dimensional trajectories of probe transport in a viscous liquid as a tool for complex-trajectory analysis. These computer simulations illustrate cases that are physically relevant and highlight key features, such as spatial confinements or convective speeds, which can for example define a cell’s internal structure and active transport along tubules or fibers. Comparison to experimental data will allow quantitative identification of various concurrent processes and understanding of their time dependence. We examine several well-defined cases of particle motion that occur in soft samples, including living cells, and present information from the analysis as well as new approaches for complex processes.     

Solubilization of bituminous and lignite coals by chemically and biologically synthesized surfactants

Tween 80 (polyoxyethylene sorbitan monooleate), Triton X-100 (nonaethylene glycol octylphenol ether), and SDS (sodium dodecyl sulfate) solubilized several components of Mississippi Wilcox lignite and Illinois No. 6 bituminous coal. Tween 80 extraction of alkali-soluble Ugljevik lignite resulted in an increase in hydrogen content and decreases in the nitrogen and sulfur contents of undissolved coal solids. Biosurfactant-containing cell-free extracts of Bacillus licheniformis solubilized a 53 000 Da coal component of Mississippi Wilcox lignite. The results suggest that solubilization of coal organic components by chemically- and biologically-synthesized surfactants has potential in terms of upgrading coals.     

Observing and imitating the formation of object classes during the second year of life.

Used a pretest–posttest design with modeling and control groups to assess the impact of modeling on deferred imitation of groupings based on object similarity. 24 children at 3 ages (12, 18, and 24 mo) observed an adult produce class groupings and alignments of objects. By 18 and 24 mo, there was significant deferred imitation of object groupings. There was virtually no effect at 12 mo. Moreover, only at 24 mo were classified sets spatially aligned. Results indicate that observing adult classification will at least facilitate object grouping during the latter part of the 2nd yr, and that it may promote the use of spatial alignments as organizing devices or as modes of depicting object classes. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Accuracy of self-perception and group-perception as related to two leadership roles.

48 members of a coeducational sociology class were rated by their peers as regards "leadership" and "popularity." The top 7 leaders and 5 popular members were compared for accuracy of perception of group status relationships with the following results: popular members were more accurate than leaders in their perception of the popularity of others. There was no difference between leaders and popular group members in accuracy of perception of the leadership status of others. Popular members were more accurate than leaders in their perception of significant group dimensions. Popular group members did not differ from leaders in accuracy of perception of self on personality variables. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Intrinsic and extrinsic job motivations among different segments of the working population.

A selected cross-section of the working population (N = 692) was interviewed with respect to job motivations. The extent to which extrinsic or intrinsic job components were valued was found to be related to occupational level. At higher occupational levels, intrinsic job components (opportunity for self-expression, interest-value of work, etc.) were more valued. At lower occupational levels, extrinsic job components (pay, security, etc.) were more valued. No sex differences were found in the value placed on intrinsic or extrinsic factors in general. However, women placed a higher value on "good co-workers" than did men, while men placed a relatively higher value on the opportunity to use their talent or skill. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Training psychologists for hospital practice: A proposal.

Hospital practice has become increasingly important for psychologists over the past decade. However, expanded opportunities for practice require training for competency. The authors propose developing a comprehensive, systematic, and flexible program of training for hospital practice in psychology including graduate course work, supervised practicum experience, and opportunities for retraining. Recommendations for certification in hospital practice, credentialing and privileging, and continuing education are included. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Implementation of periodic boundary conditions for loading of mechanical metamaterials and other complex geometric microstructures using finite element analysis

The implementation of periodic boundary conditions (PBCs) is one of the most important and difficult steps in the computational analysis of structures and materials. This is especially true in cases such as mechanical metamaterials which typically possess intricate geometries and designs which makes finding and implementing the correct PBCs a difficult challenge. In this work, we analyze one of the most common PBCs implementation technique, as well as implement and validate an alternative generic method which is suitable to simulate any possible 2D microstructural geometry with a quadrilateral unit cell regardless of symmetry and mode of deformation. A detailed schematic of how both these methods can be employed to study 3D systems is also presented.

     

New dietetic practitioners' perspectives on their education and training

Purpose: To elucidate the complex phenomenon of dietitian professional socialization, we examined factors that influence people's decisions to pursue a career in dietetics and how education and training processes influence the professional socialization of dietitians. Methods: Participants (n=12) had less than three years of work experience and included alumni from three Canadian universities representing different models of entry to practice. Three one-on-one interviews were conducted with each participant. Results: The key influencing factor in participants' decision to pursue dietetics was the perceived congruence between dietetics and other aspects of their lives, including early interests and experiences (sports, food and cooking, an eating disorder), career aspirations (science, health care), and social networks (the desire to be a professional). A pivotal experience during high school or while enrolled in or after graduation from another program prompted participants' awareness of and subsequent decision to pursue a career in dietetics. Supportive relationships were vital to participants' professional socialization. Conclusions: Recruitment materials and education opportunities should help aspiring dietitians develop a clear idea of what being a dietitian means. Dietetic educators must attend to the informational and relational aspects involved in shaping future practitioners' dietitian identities.