Dietary supplementation with pollen enhances survival and Collembola boosts fitness of a web-building spider

Uncertainties exist about the value of non-prey food for predators that are commonly food-limited, and the dietary conditions where non-prey foods are beneficial for carnivorous species. Prior studies show that large quantities of pollen grains are intercepted in the webs of web-building spiders. We examined the nutritional benefits of pollen as a non-prey food for a common ground-dwelling, sheet web-building spider, Mermessus fradeorum (Berland) (Araneae: Linyphiidae). These predators were provided diets of prey or no prey in the presence and absence of pollen. Treatment effects were quantified by measuring predator body nutrient composition, survival, body size, and offspring production. Per unit dry weight, pollen had less nitrogen and lipids than prey, although relative quantities of these nutrients per meal were not measured. Dietary treatments altered the body tissue composition of the spiders, leading to the highest N content and lipid reserves in spiders provided with Collembola. Supplementing diets with pollen increased both juvenile and adult survival, and the greatest survivorship and offspring production was observed when spiders were provided diets of Collembola supplemented with pollen. Our results show that Collembola are high-quality prey for spiders and pollen has positive effects on nutritional status and survival of a carnivorous species. Foraging on plant material potentially promotes population growth at early and late developmental stages by supplementing diets of poor-quality prey, and preventing starvation when prey are scarce

Instrumentalization of eating improves weight loss maintenance in obesity

Aim: The purpose of this study was to identify psychosocial determinants for maintaining weight loss. Methods: 42 obese individuals who achieved a 12% weight loss before entering a 52-week weight maintenance program were interviewed qualitatively. Psychosocial factors related to weight loss maintenance were identified in two contrasting groups: weight reducers and weight regainers. Groups were defined by health-relevant weight maintenance (additional weight loss > 3% at week 52, n = 9 versus weight gain > 3%, at week 52, n = 20). Results: Weight reducers reported structured meal patterns (p = 0.008), no comfort eating (p = 0.016) and less psychosocial stress (p = 0.04) compared to weight regainers. The ability to instrumentalize eating behavior emerged as an important factor (p = 0.007). Nutritional knowledge, motivation or exercise level did not differ between groups (p > 0.05). Conclusions: Successful weight loss maintenance was associated with an interplay between behavioral, affective and contextual changes. ‘Instrumentalization of eating behavior' seems to be an important element in long-term weight maintenance

Proposing a Conceptual Framework to Address Social Norms That Influence Adolescent Sexual and Reproductive Health.

With 1.8 billion young people aged 10–24 years in the world today, the cohort of adolescents and youth is the largest in history. Concurrently, millions of adolescents are confronting sexual and reproductive health (SRH) challenges, including high rates of unmet need for contraception, unintended pregnancy, and clandestine and unsafe abortion. Social norms—or shared understandings of how oneself and others should behave—can alleviate or exacerbate these challenges. Rapid global changes over the past 25 years have increased the spotlight on the interrelationships between social norms, health, and development

Stomatal Function Requires Pectin De-methyl-esterification of the Guard Cell Wall

Stomatal opening and closure depends on changes in turgor pressure acting within guard cells to alter cell shape. The extent of these shape changes is limited by the mechanical properties of the cells, which will be largely dependent on the structure of the cell walls. Although it has long been observed that guard cells are anisotropic due to differential thickening and the orientation of cellulose microfibrils, our understanding of the composition of the cell wall that allows them to undergo repeated swelling and deflation remains surprisingly poor. Here, we show that the walls of guard cells are rich in unesterified pectins. We identify a pectin methylesterase gene, PME6, which is highly expressed in guard cells and required for stomatal function. pme6-1 mutant guard cells have walls enriched in methyl-esterified pectin and show a decreased dynamic range in response to triggers of stomatal opening/closure, including elevated osmoticum, suggesting that abrogation of stomatal function reflects a mechanical change in the guard cell wall. Altered stomatal function leads to increased conductance and evaporative cooling, as well as decreased plant growth. The growth defect of the pme6-1 mutant is rescued by maintaining the plants in elevated CO2, substantiating gas exchange analyses, indicating that the mutant stomata can bestow an improved assimilation rate. Restoration of PME6 rescues guard cell wall pectin methyl-esterification status, stomatal function, and plant growth. Our results establish a link between gene expression in guard cells and their cell wall properties, with a corresponding effect on stomatal function and plant physiology

Internal construct validity of the Shirom-Melamed Burnout Questionnaire (SMBQ)

<p>Abstract</p> <p>Background</p> <p>Burnout is a mental condition defined as a result of continuous and long-term stress exposure, particularly related to psychosocial factors at work. This paper seeks to examine the psychometric properties of the Shirom-Melamed Burnout Questionnaire (SMBQ) for validation of use in a clinical setting.</p> <p>Methods</p> <p>Data from both a clinical (319) and general population (319) samples of health care and social insurance workers were included in the study. Data were analysed using both classical and modern test theory approaches, including Confirmatory Factor Analysis (CFA) and Rasch analysis.</p> <p>Results</p> <p>Of the 638 people recruited into the study 416 (65%) persons were working full or part time. Data from the SMBQ failed a CFA, and initially failed to satisfy Rasch model expectations. After the removal of 4 of the original items measuring tension, and accommodating local dependency in the data, model expectations were met. As such, the total score from the revised scale is a sufficient statistic for ascertaining burnout and an interval scale transformation is available. The scale as a whole was perfectly targeted to the joint sample. A cut point of 4.4 for severe burnout was chosen at the intersection of the distributions of the clinical and general population.</p> <p>Conclusion</p> <p>A revised 18 item version of the SMBQ satisfies modern measurement standards. Using its cut point it offers the opportunity to identify potential clinical cases of burnout.</p