The development of a natural plankton population in an outdoor tank with nutrient-poor sea water. II. Changes in dissolved carbohydrates and amino acids

terrelations between plankton communities and dissolved carbohydrates and amino acids were investigated under near-natural conditions in sea water enclosed in plastic tanks. In summer 1972 the development of a natural plankton population was followed in a 3-m3 plastic tank for 28 d. In the course of this experiment, concentrations of dissolved neutral carbohydrates and free amino acids were determined. Results are in the range of published data for the open sea with respect to concentrations (0.2-2.5 pnoles dm-3 total sugar; 0.2-3.1 pnoles dm3 total amino acids) and qualitative composition. A plankton succession was observed during the experiment; this was accompanied by distinct alterations in the concentrations of dissolved amino acids and carbohydrates. Glucose and lysine occurred in highest concentrations. Maximum rate of increase was 29 nmoles dm3 h-' for glucose, and 25 nmoles dm3 h-' for lysine. The rates of decrease are in the same range as bacterial uptake rates determined by various authors employing tracer methods. Numerous positive, highly significant correlations suggest heteropoly- saccharides as one source of individual carbohydrates. Relations between certain species within the plankton succession and occurrence of dissolved organic substances were observed. Significant positive correlations existed between glucose and diatoms as well as between glucose, galactose, mannose, arabinose and ribose and phytoplankton biomass. There were also several significant positive correlations of amino acids, especially of valine, leucine and isoleucine with other biological parameters

Discrimination as a frame-of-reference effect in overlapping friendship communities of ethnically diverse youth

Objectives: To what extent is the frame of reference of overlapping friendship communities important for young people’s feelings of discrimination and subjective wellbeing? That is, do youth feel better or worse to the extent that they feel less or more discrimination than their friends? Methods: Participants (N=898; Mage=14.13; SDage=3.37; 46% females; 46% Whites; 20% Indigenous; 34% other minorities) were high school students of three ethnically diverse, low SES public schools in New South Wales, Australia. Cross-sectional data were collected to measure felt discrimination, mental health, subjective wellbeing, social support and nominations of close friends. A state-of-the-art method of clustering links was used to identify overlapping friendship communities, and multiple membership multilevel models were run to examine whether community level discrimination moderated the link between individual level discrimination and wellbeing. Results: When the community level discrimination was low, there was no wellbeing related cost or benefit of individual level discrimination. But when the community level discrimination was high, individuals in those communities who themselves felt low discrimination had better wellbeing than individuals who themselves felt high discrimination. Conclusions: We provide evidence for a frame-ofreference effect involving discrimination. Individuals’ relative standing in their friendship communities with high group-level discrimination reliably predicted the individuals’ wellbeing levels, regardless of ethnicity. The results highlight the importance of identifying overlapping friendship communities for understanding the dynamics of discrimination and wellbeing of ethnically diverse youth

Subtype-Specific Differences in Gag- Protease-Driven Replication Capacity Are Consistent with Intersubtype Differences in HIV-1 Disease Progression

ABSTRACT There are marked differences in the spread and prevalence of HIV-1 subtypes worldwide, and differences in clinical progression have been reported. However, the biological reasons underlying these differences are unknown. Gag-protease is essential for HIV-1 replication, and Gag-protease-driven replication capacity has previously been correlated with disease progression. We show that Gag-protease replication capacity correlates significantly with that of whole isolates ( r = 0.51; P = 0.04), indicating that Gag-protease is a significant contributor to viral replication capacity. Furthermore, we investigated subtype-specific differences in Gag-protease-driven replication capacity using large well-characterized cohorts in Africa and the Americas. Patient-derived Gag-protease sequences were inserted into an HIV-1 NL4-3 backbone, and the replication capacities of the resulting recombinant viruses were measured in an HIV-1-inducible reporter T cell line by flow cytometry. Recombinant viruses expressing subtype C Gag-proteases exhibited substantially lower replication capacities than those expressing subtype B Gag-proteases ( P &lt; 0.0001); this observation remained consistent when representative Gag-protease sequences were engineered into an HIV-1 subtype C backbone. We identified Gag residues 483 and 484, located within the Alix-binding motif involved in virus budding, as major contributors to subtype-specific replicative differences. In East African cohorts, we observed a hierarchy of Gag-protease-driven replication capacities, i.e., subtypes A/C &lt; D &lt; intersubtype recombinants ( P &lt; 0.0029), which is consistent with reported intersubtype differences in disease progression. We thus hypothesize that the lower Gag-protease-driven replication capacity of subtypes A and C slows disease progression in individuals infected with these subtypes, which in turn leads to greater opportunity for transmission and thus increased prevalence of these subtypes. IMPORTANCE HIV-1 subtypes are unevenly distributed globally, and there are reported differences in their rates of disease progression and epidemic spread. The biological determinants underlying these differences have not been fully elucidated. Here, we show that HIV-1 Gag-protease-driven replication capacity correlates with the replication capacity of whole virus isolates. We further show that subtype B displays a significantly higher Gag-protease-mediated replication capacity than does subtype C, and we identify a major genetic determinant of these differences. Moreover, in two independent East African cohorts we demonstrate a reproducible hierarchy of Gag-protease-driven replicative capacity, whereby recombinants exhibit the greatest replication, followed by subtype D, followed by subtypes A and C. Our data identify Gag-protease as a major determinant of subtype differences in disease progression among HIV-1 subtypes; furthermore, we propose that the poorer viral replicative capacity of subtypes A and C may paradoxically contribute to their more efficient spread in sub-Saharan Africa. </jats:p

Possible new Arkansas endemic plant revealed by DNA sequence analysis, A

Cardamine angustata var. ouachitana, a wildflower in the mustard family (Brassicaceae), was described by Smith in 1982 to include a form of Cardamine found only in the Ouachita Mountains of Arkansas. This variety is morphologically very similar to typical Cardamine angustata. The major difference noted by Smith for the two varieties was the complete lack of leaf hairs (trichomes) in the new variety, whereas typical Cardamine angustata normally possesses trichomes. However, Al-Shehbaz rejected the variety ouachitana and reduced it to synonymy with the typical C. angustata. The recommendation of Al-Shehbaz has been followed and the taxon Cardamine angustata var. ouachitana is currently not accepted by most plant taxonomists. We performed a preliminary evaluation of the status of Cardamine angustata var. ouachitana by comparing ribosomal internal transcribed spacer region DNA sequences from specimens of Cardamine angustata var. ouachitana with sequences of Cardamine angustata from the main range of the species and other related species of Cardamine. Phylogenetic analyses of these data produced an unexpected result; specimens of C. angustata var. ouachitana were actually closely related to C. concatenata, rather than the expected close relationship with C. angustata. However, C. angustata var. ouachitana is morphologically distinct from C. concatenata. These results suggest that Cardamine angustata var. ouachitana is actually a new species found only in the Ouachita Mountains of Arkansas

Protocol for a cluster randomised controlled trial of an intervention to improve the mental health support and training available to secondary school teachers – the WISE (Wellbeing in Secondary Education) study

This is the final version of the article. Available from the publisher via the DOI in this record.BACKGROUND: Teachers are reported to be at increased risk of common mental health disorders compared to other occupations. Failure to support teachers adequately may lead to serious long-term mental disorders, poor performance at work (presenteeism), sickness absence and health-related exit from the profession. It also jeopardises student mental health, as distressed staff struggle to develop supportive relationships with students, and such relationships are protective against student depression. A number of school-based trials have attempted to improve student mental health, but these have mostly focused on classroom based approaches and have failed to establish effectiveness. Only a few studies have introduced training for teachers in supporting students, and none to date have included a focus on improving teacher mental health. This paper sets out the protocol (version 4.4 20/07/16) for a study aiming to address this gap. METHODS: Cluster randomised controlled trial with secondary schools as the unit of randomisation. Intervention schools will receive: i) Mental Health First Aid (MHFA) training for a group of staff nominated by their colleagues, after which they will set up a confidential peer support service for colleagues ii) training in MHFA for schools and colleges for a further group of teachers, which will equip them to more effectively support student mental health iii) a short mental health awareness raising session and promotion of the peer support service for all teachers. Comparison schools will continue with usual practice. The primary outcome is teacher wellbeing measured using the Warwick Edinburgh Mental Wellbeing Scale (WEMWBS). Secondary outcomes are teacher depression, absence and presenteeism, and student wellbeing, mental health difficulties, attendance and attainment. Measures will be taken at baseline, one year follow up (teachers only) and two year follow up. Economic and process evaluations will be embedded within the study. DISCUSSION: This study will establish the effectiveness and cost-effectiveness of an intervention that supports secondary school teachers’ wellbeing and mental health, and improves their skills in supporting students. It will also provide information regarding intervention implementation and sustainability.This research study is funded by the National Institute for Health Research Public Health Research (NIHR PHR) Programme (project number 13/164/06). The views and opinions expressed in the paper are those of the authors and do not necessarily reflect those of the NIHR PHR Programme or the Department of Health. The intervention is jointly funded by Public Health Wales, Public Health England and Bristol City Council. The pilot study that led to this RCT was funded by the National Institute for Health Research’s School for Public Health Research (NIHR SPHR)

A cluster randomised controlled trial of the Wellbeing in Secondary Education (WISE) Project – an intervention to improve the mental health support and training available to secondary school teachers: protocol for an integrated process evaluation

This is the author accepted manuscript. The final version is available from BioMed Central via the DOI in this record.Background Secondary school teachers have low levels of wellbeing and high levels of depression compared with the general population. Teachers are in a key position to support students, but poor mental health may be a barrier to doing so effectively. The Wellbeing in Secondary Education (WISE) project is a cluster randomised controlled trial (RCT) of an intervention to improve the mental health support and training available to secondary school teachers through delivery of the training package Mental Health First Aid and a staff peer support service. We will conduct a process evaluation as part of the WISE trial to support the interpretation of trial outcomes and refine intervention theory. The domains assessed will be: the extent to which the hypothesised mechanisms of change are activated; system level influences on these mechanisms; programme differentiation and usual practice; intervention implementation, including any adaptations; intervention acceptability; and intervention sustainability. Methods Research questions will be addressed via quantitative and qualitative methods. All study schools (n = 25) will provide process evaluation data, with more detailed focus group, interview and observation data being collected from a subsample of case study schools (4 intervention and 4 control). Mechanisms of change, as outlined in a logic model, will be measured via teacher and student surveys and focus groups. School context will be explored via audits of school practice that relate to mental health and wellbeing, combined with stakeholder interviews and focus groups. Implementation of the training and peer support service will be assessed via training observations, training participant evaluation forms, focus groups with participants, interviews with trainers and peer support service users, and peer supporter logs recording help provided. Acceptability and sustainability will be examined via interviews with funders, head teachers, trainers and peer support services users, and focus groups with training participants. Discussion The process evaluation embedded within the WISE cluster RCT will illuminate how and why the intervention was effective, ineffective or conferred iatrogenic effects. It will contribute to the refinement of the theory underpinning the intervention, and will help to inform any future implementation. Trial registration International Standard Randomised Controlled Trial Number: ISRCTN95909211 registered on 24 March 2016.The work was undertaken with the support of The Centre for the Development and Evaluation of Complex Interventions for Public Health Improvement (DECIPHer), a UKCRC Public Health Research Centre of Excellence. Joint funding (MR/KO232331/1) from the British Heart Foundation, Cancer Research UK, Economic and Social Research Council, Medical Research Council, the Welsh Government and the Wellcome Trust, under the auspices of the UK Clinical Research Collaboration, is gratefully acknowledged. The authors acknowledge the contribution of the WISE Study research administrators Amy Bond and Odell Harris

The Nuclear Sigma Term in the Skyrme Model: Pion-Nucleus Interaction

The nuclear sigma term is calculated including the nuclear matrix element of the derivative of the NN interaction with respect to the quark mass, $m_q\frac{\partial V_{NN}}{\partial m_q}$. The NN potential is evaluated in the skyrmion-skyrmion picture within the quantized product ansatz. The contribution of the NN potential to the nuclear sigma term provides repulsion to the pion-nucleus interaction. The strength of the s-wave pion-nucleus optical potential is estimated including such contribution. The results are consistent with the analysis of the experimental data.Comment: 16 pages (latex), 3 figures (eps), e-mail: [email protected] and [email protected]