The role of the cortical cytoskeleton

We generated Dictyostelium double mutants lacking the two F-actin crosslinking proteins alpha-actinin and gelation factor by inactivating the corresponding genes via homologous recombination. Here we investigated the consequences of these deficiencies both at the single cell level and at the multicellular stage. We found that loss of both proteins severely affected growth of the mutant cells in shaking suspension, and led to a reduction of cell size from 12 microns in wild-type cells to 9 microns in mutant cells. Moreover the cells did not exhibit the typical polarized morphology of aggregating Dictyostelium cells but had a more rounded cell shape, and also exhibited an increased sensitivity towards osmotic shock and a reduced rate of phagocytosis. Development was heavily impaired and never resulted in the formation of fruiting bodies. Expression of developmentally regulated genes and the final developmental stages that were reached varied, however, with the substrata on which the cells were deposited. On phosphate buffered agar plates the cells were able to form tight aggregates and mounds and to express prespore and prestalk cell specific genes. Under these conditions the cells could perform chemotactic signalling and cell behavior was normal at the onset of multicellular development as revealed by time-lapse video microscopy. Double mutant cells were motile but speed was reduced by approximately 30% as compared to wild type. These changes were reversed by expressing the gelation factor in the mutant cells. We conclude that the actin assemblies that are formed and/or stabilized by both F-actin crosslinking proteins have a protective function during osmotic stress and are essential for proper cell shape and motility

Influence of forest-to-silvopasture conversion and drought on components of evapotranspiration

The northeastern U.S. is projected to experience more frequent short-term (1-2 month) droughts interspersed among larger precipitation events. Agroforestry practices such as silvopasture may mitigate these impacts of climate change while maintaining economic benefits of both agricultural and forestry practices. This study evaluated the effects of forest-to-silvopasture (i.e., 50% thinning) conversion on the components of evapotranspiration (transpiration, rainfall interception, and soil evaporation) during the growing season of 2016. The study coincided with a late-summer drought throughout the northeastern U.S., which allowed us to also evaluate the effects of forest-to-silvopasture conversion on drought responses of multiple tree species, including Pinus strobus, Tsuga canadensis, and Quercus rubra. In the reference forest and silvopasture, we observed declining soil moisture and tree water use during the drought for all three tree species. However, the decline in P. strobus water use in response to declining soil moisture in the silvopasture was not as steep as compared with the reference forest, resulting in greater water use in the silvopasture for this species. In contrast, we did not detect different water-use responses between forest and silvopasture in T. canadensis or Q. rubra. This suggests that forest-to-silvopasture conversion via thinning can alleviate drought stress for P. strobus and that this species may be more sensitive to moisture stress when competition for water is high in denser stands. Evapotranspiration was 35% lower in the silvopasture compared with the reference forest, primarily a result of lower transpiration and rainfall interception. While soil evaporation was greater in the silvopasture, this was not enough to offset the considerably lower transpiration and interception. We observed greater radial tree growth 1-3 years following conversion in the silvopasture as compared with the reference forest for T. canadensis and Q. rubra, but not for P. strobus. Overall, our results suggest that forest conversion to silvopasture (in lieu of clearcutting for new pasture) may mitigate the impacts of agricultural land use intensification and climate change on ecosystem services, especially in terms of sustaining hydrologic regulation functions. Further study is required to determine the generality of these results and whether these benefits extend beyond the first few years post-conversion

Wellbeing measures for workers: a systematic review and methodological quality appraisal

IntroductionIncreasing attention on workplace wellbeing and growth in workplace wellbeing interventions has highlighted the need to measure workers' wellbeing. This systematic review sought to identify the most valid and reliable published measure/s of wellbeing for workers developed between 2010 to 2020.MethodsElectronic databases Health and Psychosocial Instruments, APA PsycInfo, and Scopus were searched. Key search terms included variations of [wellbeing OR “well-being”] AND [employee*OR worker*OR staff OR personnel]. Studies and properties of wellbeing measures were then appraised using Consensus-based Standards for the selection of health Measurement Instruments.ResultsEighteen articles reported development of new wellbeing instruments and eleven undertook a psychometric validation of an existing wellbeing instrument in a specific country, language, or context. Generation and pilot testing of items for the 18 newly developed instruments were largely rated 'Inadequate'; only two were rated as 'Very Good'. None of the studies reported measurement properties of responsiveness, criterion validity, or content validity. The three instruments with the greatest number of positively rated measurement properties were the Personal Growth and Development Scale, The University of Tokyo Occupational Mental Health well-being 24 scale, and the Employee Well-being scale. However, none of these newly developed worker wellbeing instruments met the criteria for adequate instrument design.DiscussionThis review provides researchers and clinicians a synthesis of information to help inform appropriate instrument selection in measurement of workers' wellbeing.Systematic review registrationhttps://www.crd.york.ac.uk/prospero/display_record.php?RecordID=79044, identifier: PROSPERO, CRD42018079044

Network analysis of mindfulness facets, affect, compassion, and distress.

Objectives: Mindfulness, positive affect, and compassion may protect against psychological distress but there is lack of understanding about the ways in which these factors are linked to mental health. Network analysis is a statistical method used to investigate complex associations among constructs in a single network and is particularly suitable for this purpose. The aim of this study was to explore how mindfulness facets, affect, and compassion were linked to psychological distress using network analysis. Methods: The sample (n = 400) included equal numbers from general and student populations who completed measures of five mindfulness facets, compassion, positive and negative affect, depression, anxiety, and stress. Network analysis was used to explore the direct associations between these variables. Results: Compassion was directly related to positive affect, which in turn was strongly and inversely related to depression and positively related to the observing and describing facets of mindfulness. The non-judgment facet of mindfulness was strongly and inversely related to negative affect, anxiety, and depression, while non-reactivity and acting with awareness were inversely associated with stress and anxiety, respectively. Strong associations were found between all distress variables. Conclusions: The present network analysis highlights the strong link between compassion and positive affect and suggests that observing and describing the world through the lens of compassion may enhance resilience to depression. Taking a non-judging and non-reacting stance toward internal experience while acting with awareness may protect against psychological distress. Applicability of these findings can be examined in experimental studies aiming to prevent distress and enhance psychological well-being

Cognitive effect following a blended (face to face and videoconference-delivered) format mindfulness training

While evidence supports the feasibility of online mindfulness training (MT), the effect of this approach on cognition remains unclear. The present study investigated changes in cognition following a newly developed 6-week videoconference-delivered MT program on cognitive function in two groups. The first group (n = 17) had two baseline assessments prior to MT [3 weeks after group two (n = 15)] to allow for evaluation of practice and learning effects. Four participants from each group were excluded from the final analysis due to missing data. Following MT, there was an improvement in switching of attention, working memory, executive function, and social cognition, but some of these effects were not easily accounted for by learning or practice effects. No significant changes were found on tasks measuring sustained attention, cognitive flexibility and inhibition, information processing, and sensory-motor function. Our findings suggest that domain-specific cognition might be enhanced by a brief videoconference-delivered MT, and larger, controlled studies to delineate the effects of online MT on subdomains of cognition are needed

Effectiveness of a clinical pathway for acute stroke care in a district general hospital: an audit

BACKGROUND: Organised stroke care saves lives and reduces disability. A clinical pathway might be a form of organised stroke care, but the evidence for the effectiveness of this model of care is limited. METHODS: This study was a retrospective audit study of consecutive stroke admissions in the setting of an acute general medical unit in a district general hospital. The case-notes of patients admitted with stroke for a 6-month period before and after introduction of the pathway, were reviewed to determine data on length of stay, outcome, functional status, (Barthel Index, BI and Modified Rankin Scale, MRS), Oxfordshire Community Stroke Project (OCSP) sub-type, use of investigations, specific management issues and secondary prevention strategies. Logistic regression was used to adjust for differences in case-mix. RESULTS: N = 77 (prior to the pathway) and 76 (following the pathway). The median (interquartile range, IQR) age was 78 years (67.75–84.25), 88% were European NZ and 37% were male. The median (IQR) BI at admission for the pre-pathway group was less than the post-pathway group: 6 (0–13.5) vs. 10 (4–15.5), p = 0.018 but other baseline variables were statistically similar. There were no significant differences between any of the outcome or process of care variables, except that echocardiograms were done less frequently after the pathway was introduced. A good outcome (MRS<4) was obtained in 66.2% prior to the pathway and 67.1% after the pathway. In-hospital mortality was 20.8% and 23.1%. However, using logistic regression to adjust for the differences in admission BI, it appeared that admission after the pathway was introduced had a significant negative effect on the probability of good outcome (OR 0.29, 95%CI 0.09-0.99). CONCLUSION: A clinical pathway for acute stroke management appeared to have no benefit for the outcome or processes of care and may even have been associated with worse outcomes. These data support the conclusions of a recent Cochrane review

A cross-sectional online survey of depression symptoms among New Zealand’s Asian community in the first 10 months of the COVID-19 pandemic

The COVID-19 pandemic has elevated levels of distress and resulted in anti-Asian discrimination in many countries. We aimed to determine the 10-month prevalence of depression symptoms in Asian adults in New Zealand during the pandemic and to see if this was related to experience of racism. An online survey was conducted and a stratified sample of 402 respondents completed the brief Centre for Epidemiological Studies-Depression (CES-D) scale. Analyses included: descriptive statistics, depression scores by age/gender, factor analysis of the 10 item CES-D and partial correlation network analysis of CES-D items together with questions about experience of racism. Results show that half of the sample reported clinically significant symptoms of depression. Depression was higher among younger participants but there was no gender difference. Internal consistency was high (α = 0.85) for the CES-D which revealed a clear two-factor structure. Network analysis suggested that sleeping problems might be the bridge between experiences of racism and depression. The prevalence of low mood was high with clinically significant levels of depressive symptoms. Depression was higher in younger people and had a modest positive correlation with personal experience of racism

Exploitation of Other Social Amoebae by Dictyostelium caveatum

Dictyostelium amoebae faced with starvation trigger a developmental program during which many cells aggregate and form fruiting bodies that consist of a ball of spores held aloft by a thin stalk. This developmental strategy is open to several forms of exploitation, including the remarkable case of Dictyostelium caveatum, which, even when it constitutes 1/10(3) of the cells in an aggregate, can inhibit the development of the host and eventually devour it. We show that it accomplishes this feat by inhibiting a region of cells, called the tip, which organizes the development of the aggregate into a fruiting body. We use live-cell microscopy to define the D. caveatum developmental cycle and to show that D. caveatum amoebae have the capacity to ingest amoebae of other Dictyostelid species, but do not attack each other. The block in development induced by D. caveatum does not affect the expression of specific markers of prespore cell or prestalk cell differentiation, but does stop the coordinated cell movement leading to tip formation. The inhibition mechanism involves the constitutive secretion of a small molecule by D. caveatum and is reversible. Four Dictyostelid species were inhibited in their development, while D. caveatum is not inhibited by its own compound(s). D. caveatum has evolved a predation strategy to exploit other members of its genus, including mechanisms of developmental inhibition and specific phagocytosis

Shadowing in Inelastic Scattering of Muons on Carbon, Calcium and Lead at Low XBj

Nuclear shadowing is observed in the per-nucleon cross-sections of positive muons on carbon, calcium and lead as compared to deuterium. The data were taken by Fermilab experiment E665 using inelastically scattered muons of mean incident momentum 470 GeV/c. Cross-section ratios are presented in the kinematic region 0.0001 < XBj <0.56 and 0.1 < Q**2 < 80 GeVc. The data are consistent with no significant nu or Q**2 dependence at fixed XBj. As XBj decreases, the size of the shadowing effect, as well as its A dependence, are found to approach the corresponding measurements in photoproduction.Comment: 22 pages, incl. 6 figures, to be published in Z. Phys.