Symplectic structure of the moduli space of flat connections on a Riemann surface

We consider canonical symplectic structure on the moduli space of flat {\g}-connections on a Riemann surface of genus $g$ with $n$ marked points. For {\g} being a semisimple Lie algebra we obtain an explicit efficient formula for this symplectic form and prove that it may be represented as a sum of $n$ copies of Kirillov symplectic form on the orbit of dressing transformations in the Poisson-Lie group $G^{*}$ and $g$ copies of the symplectic structure on the Heisenberg double of the Poisson-Lie group $G$ (the pair ($G,G^{*}$) corresponds to the Lie algebra {\g}).Comment: 20 page

Comparing two tools for ecosystem service assessments regarding water resources decisions

We present a comparison of two ecohydrologic models commonly used for planning land management to assess the production of hydrologic ecosystem services: the Soil and Water Assessment Tool (SWAT) and the Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) annual water yield model. We compare these two models at two distinct sites in the US: the Wildcat Creek Watershed in Indiana and the Upper Upatoi Creek Watershed in Georgia. The InVEST and SWAT models provide similar estimates of the spatial distribution of water yield in Wildcat Creek, but very different estimates of the spatial distribution of water yield in Upper Upatoi Creek. The InVEST model may do a poor job estimating the spatial distribution of water yield in the Upper Upatoi Creek Watershed because baseflow provides a significant portion of the site’s total water yield, which means that storage dynamics which are not modeled by InVEST may be important. We also compare the ability of these two models, as well as one newly developed set of ecosystem service indices, to deliver useful guidance for land management decisions focused on providing hydrologic ecosystem services in three particular decision contexts: environmental flow ecosystem services, ecosystem services for potable water supply, and ecosystem services for rainfed irrigation. We present a simple framework for selecting models or indices to evaluate hydrologic ecosystem services as a way to formalize where models deliver useful guidance

Effects of adding a new PCMH block rotation and resident team to existing longitudinal training within a certified PCMH: primary care residents’ attitudes, knowledge, and experience

Background: Although the patient-centered medical home (PCMH) model is considered important for the future of primary care in the USA, it remains unclear how best to prepare trainees for PCMH practice and leadership. Following a baseline study, the authors added a new required PCMH block rotation and resident team to an existing longitudinal PCMH immersion and didactic curriculum within a Level 3-certified PCMH, aiming for “enhanced situated learning”. All 39 residents enrolled in a USA family medicine residency program during the first year of curricular implementation completed this new 4-week rotation. This study examines the effects of this rotation after 1 year. Methods: A total of 39 intervention and 13 comparison residents were eligible participants. This multimethod study included: 1) individual interviews of postgraduate year (PGY) 3 intervention vs PGY3 comparison residents, assessing residents’ PCMH attitudes, knowledge, and clinical experience, and 2) routine rotation evaluations. Interviews were audiorecorded, transcribed, and analyzed using immersion/crystallization. Rotation evaluations were analyzed using descriptive statistics and qualitative analysis of free text responses. Results: Authors analyzed 23 interviews (88%) and 26 rotation evaluations (67%). Intervention PGY3s’ interviews revealed more nuanced understanding of PCMH concepts and more experience with system-level PCMH tasks than those of comparison PGY3s. More intervention PGY3s rated themselves “extremely prepared” to implement PCMH than comparison PGY3s; however, most self-rated “somewhat prepared”. Their reflections demonstrated deeper understanding of PCMH implementation and challenges than comparison PGY3s but inadequate experience to directly see the results of successful solutions. Rotation evaluations from PGY1, PGY2, and PGY3s revealed strengths and several areas for improvement. Conclusion: Adding one 4-week block rotation to existing longitudinal training appears to improve residents’ PCMH knowledge, skills, and experience from “basic” to “intermediate”. However, this training level appears inadequate for PCMH leadership or for teaching junior learners. Further study is needed to determine the optimum training for different settings

Grey-matter texture abnormalities and reduced hippocampal volume are distinguishing features of schizophrenia

Neurodevelopmental processes are widely believed to underlie schizophrenia. Analysis of brain texture from conventional magnetic resonance imaging (MRI) can detect disturbance in brain cytoarchitecture. We tested the hypothesis that patients with schizophrenia manifest quantitative differences in brain texture that, alongside discrete volumetric changes, may serve as an endophenotypic biomarker. Texture analysis (TA) of grey matter distribution and voxel-based morphometry (VBM) of regional brain volumes were applied to MRI scans of 27 patients with schizophrenia and 24 controls. Texture parameters (uniformity and entropy) were also used as covariates in VBM analyses to test for correspondence with regional brain volume. Linear discriminant analysis tested if texture and volumetric data predicted diagnostic group membership (schizophrenia or control). We found that uniformity and entropy of grey matter differed significantly between individuals with schizophrenia and controls at the fine spatial scale (filter width below 2 mm). Within the schizophrenia group, these texture parameters correlated with volumes of the left hippocampus, right amygdala and cerebellum. The best predictor of diagnostic group membership was the combination of fine texture heterogeneity and left hippocampal size. This study highlights the presence of distributed grey-matter abnormalities in schizophrenia, and their relation to focal structural abnormality of the hippocampus. The conjunction of these features has potential as a neuroimaging endophenotype of schizophrenia

Randomized controlled trial of a book-sharing intervention in a deprived South African community: effects on carer-infant interactions, and their relation to infant cognitive and socio-emotional outcome

Background: Consistent with evidence from high income countries, we previously showed that, in an informal peri-urban settlement in a low-middle income country, training parents in book-sharing with their infants benefitted infant language and attention (Vally et al., 2015). Here, we investigated whether these benefits were explained by improvements in carer-infant interactions in both book-sharing and non-book-sharing contexts. We also explored whether infant socio-emotional development benefitted from book-sharing. Methods: We conducted a randomized controlled trial in Khayelitsha, South Africa. Carers of 14-16 month-old infants were randomized to 8 weeks’ training in book-sharing (n = 49) or a wait list control group (n = 42). In addition to the cognitive measures reported previously, independent assessments were made at base line and follow-up of carer-infant interactions during book-sharing and toy play. Assessments were also made, at follow-up only, of infant pro-social behaviour in a ‘help task’, and of infant imitation of doll characters’ non-social actions and an interpersonal interaction. Eighty-two carer-infant pairs (90%) were assessed at follow-up. (Trial registration ISRCTN39953901). Results: Carers who received the training showed significant improvements in book-sharing interactions (sensitivity, elaborations, reciprocity), and, to a smaller extent, in toy-play interactions (sensitivity). Infants in the intervention group showed a significantly higher rate of pro-social behaviour, and tended to show more frequent imitation of the interpersonal interaction. Improvements in carer behaviour during book-sharing, but not during toy play, mediated intervention effects on all infant cognitive outcomes, and tended to mediate intervention effects on infant interpersonal imitation. Conclusions: Training in book sharing, a simple, inexpensive intervention that has been shown to benefit infant cognitive development in a low-middle income country, also shows promise for improving infant socio-emotional outcomes in this context. Benefits are mediated by improvements in carer-infant interactions, particularly in book-sharing contexts

Oligodendrocyte Death in Pelizaeus-Merzbacher Disease Is Rescued by Iron Chelation.

Pelizaeus-Merzbacher disease (PMD) is an X-linked leukodystrophy caused by mutations in Proteolipid Protein 1 (PLP1), encoding a major myelin protein, resulting in profound developmental delay and early lethality. Previous work showed involvement of unfolded protein response (UPR) and endoplasmic reticulum (ER) stress pathways, but poor PLP1 genotype-phenotype associations suggest additional pathogenetic mechanisms. Using induced pluripotent stem cell (iPSC) and gene-correction, we show that patient-derived oligodendrocytes can develop to the pre-myelinating stage, but subsequently undergo cell death. Mutant oligodendrocytes demonstrated key hallmarks of ferroptosis including lipid peroxidation, abnormal iron metabolism, and hypersensitivity to free iron. Iron chelation rescued mutant oligodendrocyte apoptosis, survival, and differentiationin vitro, and post-transplantation in vivo. Finally, systemic treatment of Plp1 mutant Jimpy mice with deferiprone, a small molecule iron chelator, reduced oligodendrocyte apoptosis and enabled myelin formation. Thus, oligodendrocyte iron-induced cell death and myelination is rescued by iron chelation in PMD pre-clinical models.H.N. acknowledges postdoctoral fellowship support from the European Leukodystrophy Association, and career transition fellowship support from National Multiple Sclerosis Society. M.C. acknowledges funding support from Career Development Grant awarded by Cerebral Palsy Alliance Research Foundation Inc. This work was supported by funding from the National Multiple Sclerosis Foundation (to M.W., D.H. R.), the European Leukodystrophy Association and the New York Stem Cell Foundation (to M.W.), and Action Medical Research, the Adelson Medical Research Foundation, the National Institute for Health Research Cambridge Biomedical Research Centre and the European Research Council (to D.H. R)

Surface and Temporal Biosignatures

Recent discoveries of potentially habitable exoplanets have ignited the prospect of spectroscopic investigations of exoplanet surfaces and atmospheres for signs of life. This chapter provides an overview of potential surface and temporal exoplanet biosignatures, reviewing Earth analogues and proposed applications based on observations and models. The vegetation red-edge (VRE) remains the most well-studied surface biosignature. Extensions of the VRE, spectral "edges" produced in part by photosynthetic or nonphotosynthetic pigments, may likewise present potential evidence of life. Polarization signatures have the capacity to discriminate between biotic and abiotic "edge" features in the face of false positives from band-gap generating material. Temporal biosignatures -- modulations in measurable quantities such as gas abundances (e.g., CO2), surface features, or emission of light (e.g., fluorescence, bioluminescence) that can be directly linked to the actions of a biosphere -- are in general less well studied than surface or gaseous biosignatures. However, remote observations of Earth's biosphere nonetheless provide proofs of concept for these techniques and are reviewed here. Surface and temporal biosignatures provide complementary information to gaseous biosignatures, and while likely more challenging to observe, would contribute information inaccessible from study of the time-averaged atmospheric composition alone.Comment: 26 pages, 9 figures, review to appear in Handbook of Exoplanets. Fixed figure conversion error