Quantitative analysis of yeast internal architecture using soft X-ray tomography

We used soft X-ray tomography (SXT)--a high-resolution, quantitative imaging technique--to measure cell size and organelle volumes in yeasts. Cell size is a key factor in initiating cell division in yeasts, whereas the number and volume of the organelles have a profound impact on the function and viability of a cell. Consequently, determining these cell parameters is fundamentally important in understanding yeast biology. SXT is well suited to this type of analysis. Specimens are imaged in a near-native state, and relatively large numbers of cells can be readily analysed. In this study, we characterized haploid and diploid strains of Saccharomyces cerevisiae at each of the key stages in the cell cycle and determined the relationships that exist cellular and organelle volumes. We then compared these results with SXT data obtained from Schizosaccharomyces pombe, the three main phenotypes displayed by the opportunistic yeast pathogen Candida albicans and from a coff1-22 mutant strain of S. cerevisiae. This comparison revealed that volumetric ratios were invariant, irrespective of yeast strain, ploidy or morphology, leading to the conclusion these volumetric ratios are common in all yeasts.     

Spatial and Ontogenetic Variability of Sea Lamprey Diets in Lake Superior

Invasive sea lamprey (Petromyzon marinus) remain an important source of fish mortality in the Laurentian Great Lakes, yet assessing their impact is hindered by lack of quantitative diet information. We examined nitrogen and carbon stable isotope ratios (δ¹⁵N and δ¹³C) of sea lamprey and host species in six ecoregions of Lake Superior, mainly in 2002–2004. Data implied that most sea lamprey fed primarily on upper trophic level species, including forms of lake trout (Salvelinus namaycush). However, in Ontario waters, particularly semi-enclosed Black Bay, sea lamprey relied heavily on lower trophic levels, such as coregonines (Coregonus spp.) and suckers (Catostomus spp.). Sea lamprey δ¹⁵N and δ¹³C generally increased with sea lamprey size, implying dependence on higher trophic levels later in life. Most parasitic sea lamprey that we captured were attached to either lean lake trout (35% of observed attachments), lake whitefish (Coregonus clupeaformis; 25%), or cisco (C. artedii; 25%); the latter sea lamprey were typically < 15 g. Survey- and fishery-dependent wounding rate data compiled from 1986–2005 suggest that lean and siscowet lake trout were selectively parasitized by sea lamprey, which is consistent with our stable isotope data. Our results largely support the notion that lake trout are the principal host species in Lake Superior. However, stable isotope evidence that sea lamprey feed at lower trophic levels in some regions argues for comprehensive monitoring of sea lamprey impacts throughout the fish community in systems that sea lamprey have invaded.     

Exercise as stigma management for individuals with onset-controllable and onset-uncontrollable spinal cord injury.

Studies have suggested that individuals with physical disabilities are often stigmatized and are perceived to possess less favorable physical and psychological characteristics than individuals without disability. Purpose: To investigate whether able-bodied adults' perceptions of people with different causes of spinal cord injury (SCI) are influenced by physical activity status information. Method and Participants: Each participant (N = 198) read all five vignettes describing individuals with SCI who had varying levels of physical activity participation and cause of injury information (e.g., onset-uncontrollable [hit by impaired driver] and onset-controllable [caused by impaired driving]). After reading each vignette, participants completed a 12-item Warmth and Competence Questionnaire to evaluate each target. One-way repeated measures multivariate analyses of variance were conducted to examine the within-subjects differences. Results: Physically active individuals with onset-uncontrollable SCI were rated most favorably on warmth and competence. Physically active individuals with onset-controllable SCI also were rated more favorably on warmth and competence than physically inactive targets with onset-controllable SCI. Conclusion: A physically active lifestyle may be beneficial in managing the stigma experienced by individuals with both onset-controllable and onset-uncontrollable SCI. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Engineering-Based Decisions in Construction

This paper uses four case studies to emphasize the fact that field engineering decisions cannot be made without a full understanding of all the technical problems involved. Two of the studies are taken from conventional design-bid-build projects and two are taken from design-build projects in which the ability to strongly influence design in the interest of construction efficiency places a new and increased emphasis on construction and field engineering skills. The cases also show that field engineering decisions frequently address new and unexpected realities, changed conditions, and transient loads, and thus they require high levels of understanding, technical analysis, and creative thought. We emphasize the need for universities and construction engineering programs to develop graduates who are capable of integrating design and construction considerations throughout the project delivery process. We also urge programs to continue to focus strongly on field engineering as the foundation for success in an increasingly complex and technically driven construction industry.     

Changes in Older Europeans’ Health Across Two Waves of SHARE: Life-Course and Societal Determinants

Building on recent research investigating the role of life-course factors (including childhood conditions) and societal context in older Europeans health status, this study investigates the determinants of changes in elders’ health across two waves of the Survey of Health Ageing and Retirement in Europe (SHARE). Controlling for individuals’ current living conditions at baseline, our analysis provides evidence for long-term associations between childhood conditions (SES, health, cognition) and health dynamics in older age. Moreover, our findings suggest that income inequality tends to increase elders’ risk of experiencing negative health changes (decreases their chance to recover from poor health, respectively). Our study underlines the importance of accounting for both life-course and societal determinants of later life health dynamics.     

Behavioral manifestations of social support: A microanalytic investigation.

Examined the specific interpersonal behaviors that convey support from one person to another, the types of interpersonal experiences that characterize individuals who report high vs low levels of social support, and the effectiveness of a range of helping behaviors in preventing depressive reactions to stressful events. 41 undergraduates completed a general measure of perceived social support and kept daily records of their social interactions and stressful experiences for 14 days. They also completed the Depression Adjective Check Lists each day. Results show that behaviors reflecting emotional support and informational support occurred as a specific response to stressful life events. Although esteem support was expressed with equal frequency in the presence and absence of stress, it was especially effective in preventing depressive reactions to stressful events. Ss who perceived themselves as having high levels of social support were more frequently the recipients of helping behaviors following stressful events than those low in perceived support. Perceived social support was only predictive of helping behaviors on days on which at least 1 stressful event occurred. The total number of helping behaviors received following stressful events was a significant negative predictor of level of depressive mood, although 1 helping behavior (frequency of confiding) was associated with higher levels of depression. Results are interpreted in terms of the buffering model of social support. (36 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Intact and long-lasting repetition priming in amnesia.

In 2 experiments, the ability of amnesic patients to exhibit long-lasting perceptual priming after a single exposure to pictures was evaluated. Ss named pictures as quickly as possible on a single occasion and later named the same pictures mixed with new pictures. In Exp 1, amnesic patients exhibited fully intact priming effects lasting at least 7 days. In Exp 2, the priming effect for both groups was shown to depend on both highly specific visual information and on less visual, more conceptual information. In contrast, recognition memory was severely impaired in the patients, as assessed by both accuracy and response time. The results provide the 1st report of a long-lasting priming effect in amnesic patients, based on a single encounter, which occurs as strongly in the patients as in normal Ss. Together with other recent findings, the results suggest that long-lasting priming and recognition memory depend on separate brain systems. (PsycINFO Database Record (c) 2010 APA, all rights reserved)