From Microscopic to Macroscopic Descriptions of Cell Migration on Growing Domains

Cell migration and growth are essential components of the development of multicellular organisms. The role of various cues in directing cell migration is widespread, in particular, the role of signals in the environment in the control of cell motility and directional guidance. In many cases, especially in developmental biology, growth of the domain also plays a large role in the distribution of cells and, in some cases, cell or signal distribution may actually drive domain growth. There is an almost ubiquitous use of partial differential equations (PDEs) for modelling the time evolution of cellular density and environmental cues. In the last 20 years, a lot of attention has been devoted to connecting macroscopic PDEs with more detailed microscopic models of cellular motility, including models of directional sensing and signal transduction pathways. However, domain growth is largely omitted in the literature. In this paper, individual-based models describing cell movement and domain growth are studied, and correspondence with a macroscopic-level PDE describing the evolution of cell density is demonstrated. The individual-based models are formulated in terms of random walkers on a lattice. Domain growth provides an extra mathematical challenge by making the lattice size variable over time. A reaction–diffusion master equation formalism is generalised to the case of growing lattices and used in the derivation of the macroscopic PDEs.     

Modified Procedure for the Microscopic and Macroscopic Study of Viral Plaques

A virus plaque method that consistently gives good visual contrast for macroscopic observation and also permits microscopic study is described. Cells are grown in plastic flasks and the gelled overlay medium can be of any desired agar concentration or volume. A fixing solution is used prior to removal of the agar overlay, and dye is added to the fixing solution or staining can follow fixation and agar removal. The bottom of the flask with the fixed monolayer is separated from the rest of the container and handled as a slide. A new mounting medium is described.     

Evaluation of Macroscopic and Microscopic Components of Partial Resistance to Leaf Rust in Durum Wheat

Leaf rust, caused by the fungus Puccinia triticina, is considered one of the most important foliar diseases in durum wheat. Hypersensitive resistance (HR) may be rapidly overcome by the pathogen when resistant cultivars are grown on a large acreage or following changes in virulence in the pathogen population. Prolonging the durability of the resistance requires uses of other types of resistance such as partial resistance (PR). In this study, six durum wheat lines provided by the International Center for Corn and Wheat Improvement (CIMMYT) with a high level of PR to leaf rust were studied in monocyclic tests in a growth chamber. Inoculations were performed on both primary and fifth leaves using the Spanish race DGB/BN. UV fluorescence microscopy was employed to determine microscopic components of the resistance, such as the number of early aborted infection units not associated with plant cell necrosis (EA?) and relative colony size (RCS) of the established infection units. Macroscopic components of PR such as latency period, infection frequency and uredinium size were measured as well. All six resistant lines were characterized by a higher EA? and smaller RCS respect to the susceptible control ‘Don Rafael’. Line 3 showed the highest level of PR. It had 22% of EA? compared with 4% in the susceptible control, and the smallest RCS (17% respect to RCS of ‘Don Rafael’) at adult plant stage. Both EA? and RCS had a high heritability (more than 97%) and the correlation with macroscopic parameters (latency period and uredinium size) was also high (significant at 0.001 level). Hence, PR to leaf rust in these durum wheat genotypes has been revealed at microscopic level (higher EA? and smaller RCS).     

Live to Work or Love to Work: Work Craving and Work Engagement

Objective

According to the theory of work craving, a workaholic has a craving for self-worth compensatory incentives and an expectation of relief from negative affect experienced through neurotic perfectionism and an obsessive-compulsive style of working. Research has shown that workaholism and work engagement should be considered as two distinct work styles with different health consequences. However, the mechanisms underlying the adoption of these work styles have been neglected. The present study proposes that work craving and work engagement are differentially associated with self-regulatory competencies and health. In particular, we expected that the working styles mediate the relationships between emotional self-regulation and health. Methods: In the cross-sectional study, 469 teachers from German schools completed online administered questionnaires. By means of structural equation modeling, we tested two indirect paths: a) from self-relaxation deficits via work craving to poor health and b) from self-motivation competencies via work engagement to good health.

Results

As expected, we found evidence that a) the negative relationship of self-relaxation deficits on health was partially mediated by work craving and b) the positive relationship of self-motivation competencies on health was partially mediated by work engagement.

Conclusions

The present study emphasizes the importance of self-regulation competencies for healthy or unhealthy work styles. Whereas work craving was associated with a low ability to down-regulate negative emotions and poor health, work engagement was associated with a high ability to up-regulate positive emotions and good health.     

The Psychology of Labor Education: Some Major Issues

Soviet psychologists have done a good deal of research on some of the problematic aspects of the labor education of our young people. E. A. Klimov, K, K. Platonov, V. V. Chebysheva, and others have done general studies of career choice among school students. The following projects also warrant special mention: on the circumstances that foster a positive attitude toward work in instructional workshops and student production teams (L. V. Blagonadyozhina, M. A. Khomutova, F. I. Ivash-chenko, and others); on the role work activity plays in shaping a child's personality and helping to develop his moral and volitional qualities and his overall activity level (T. I. Agafonov, V. E. Gurin, V. I. Selivanov, D. I. Fel'dshtein, and others); on the motives that underlie work activity and career choice in school students (K. E. Drozdova, V. I. Zhukovskaya, and others); on the psychological mechanisms that are relevant to constructive career guidance for students in the upper grades (N. I. Krylov, I. V. Mikhailov, and others); on the development of a technical mind-set in school students (E. A. Faraponova et al.) In addition, researchers in the Psychology Faculty of the Gorky Pedagogical Institute in Minsk are currently involved in a program to investigate the influence the school student's self-appraisal and expectations of productive work exert upon his personality development. Yet, for all this, as the press has frequently pointed out, the scope and spirit of research on psychological aspects of labor education are still far from satisfactory in the light of contemporary needs. Psychologists are too often absent when attempts are made to set the content and form of labor education onto a rigorously scientific foundation and to ascertain the most educationally valid types of work for a child of a given age. The psychological underpinnings of career guidance have also received an inadequate share of scholarly attention.     

Comparison of Macroscopic, Microscopic, and Radiometric Examinations of Clinical Blood Cultures in Hypertonic Media

Clinical blood cultures were collected in the Bactec 8A flask (Johnston Laboratories, Cockeysville, Md.) and examined macrosopically, microscopically, and radiometrically in an effort to determine which approach produced the fastest detection time. Of 360 blood cultures found to contain organisms by subculture, 334 were first detected by Bactec, 98 by macroscopic examination, and 68 by microscopic examination. Examination times were at 4, 8, 16, 24, 36, and 48 h after collection of the specimen. Sixteen hours after specimen collection, microscopic examination had detected 31 positive cultures, macroscopic examination had detected two positive cultures, and Bactec had detected 160 positive cultures. By the end of the first 24 h of incubation, Bactec had detected 313 (93%) of those cultures eventually found to be positive. Although Bactec produced the fastest detection time in an overwhelming majority of the cultures, it failed to detect three of three Candida spp. cultures, three of five Bacteroides spp. cultures, and six of 32 Enterococcus spp. cultures during the first 48 h of incubation.     

From Racing to Rugby: All Work and No Play for Gogodala Men of Western Province,Papua New Guinea

In this article, I analyse how Gogodala men in Western Province approach the sport of rugby league football as an extension of the practice of canoe racing. Despite colonial changes and mission attempts to redeem canoe racing by labelling them ‘cultural games’, canoe races continue to embody clan relations and demonstrate inner masculine strength, collective clan power and a local work ethic. Although there has been a general lack of attention given to studies of sport in Papua New Guinea, a discourse has emerged that analyses sports competitions as either a modern form of play and a replacement for past ritual activities or as a contemporary exemplar of warfare and other eradicated practices. As the Gogodala have not practised headhunting or warfare for over one hundred years, I want to contribute to this discussion by exploring how contemporary canoe racing and rugby league form an integral part of conceptualisations of work and dala ela gi, or ‘the male way of life’.     

Some Recent Developments in Evolutionary Approaches to the Study of Human Cognition and Behavior

In this paper I review some theoretical exchanges and empiricalresults from recent work on human behavior and cognition in thehope of indicating some productive avenues for critical engagement.I focus particular attention on methodological debates between Evolutionary Psychologists and behavioral ecologists. I argue for a broader and more encompassing approach to the evolutionarily based study of human behavior and cognition than either of these two rivals present.     

Development of Diagnostic Microscopic and Chemical Markers of Some Euphorbia Latexes

The latexes of the three Euphorbia species, namely E. antiquorum L., E. nerifolia L., and E. tirucalli L., are highly valued in the Indian system of medicine as purgatives, in addition to their specific and distinct therapeutic activities. In order to distinguish these latexes and develop their diagnostic microscopic and chemical markers, we performed extensive chemical and microscopic studies. The three latexes differ significantly in their microscopic features by exhibiting characteristic starch grain patterns. Although amoebic structures were found to be characteristic of E. antiquorum, dumb-bell and oval structures are characteristic of E. nerifolia and E. tirucalli, respectively. In addition, these latexes showed bone-shaped structures as a common feature, but these differed considerably in their length （10-60, 30-55, and 50-70 μm in length in E. antiquorum, E. nerifolia, and E. tirucalli, respectively）. The chemical markers nerifoliene and euphol were found to be common to both E. antiquorum and E. nerifolia, whereas euphol is the only marker for E. tirucalli. A reverse-phase high-performance thin-layer chromatographic （HPTLC） method was developed to distinguish these three latexes and to generate their standard fingerprinting patterns. Most significantly, the markers nerifoliene and euphol could be resolved by RP-18 F254s precoated aluminium plates and the latexes have been quantitatively estimated with respect to these markers. The developed microscopic, chemical and HPTLC patterns can be used to distinguish the three latexes.