Dynamic performance modelling of tidal stream turbines in ocean waves.

The primary aim of this work is to develop a tool to predict the lifetime performance of a tidal stream turbine. This involves the experimental validation of Blade Element Momentum Theory (BEMT) and implementation of an extended model to optimise blade design and predict performance over the operating range. Time varying non-linear upstream flows, such as wave action and velocity gradients are considered and the model is extended into the time domain to obtain the dynamic response of the rotor. In addition, to rationalise the environmental conditions that a device will encounter in its lifetime, representative sea-states and occurrences must be defined. A 1m diameter turbine is tow tested in the River Tawe. It is monitored and controlled such that the performance can be analysed over the operating range. An automated electrical control system is also tested. The results are compared to BEMT. The BEMT is numerically implemented and examined to determine its limitations. Off-optimum performance is considered. The model is extended to incorporate a time dependent flow field with additional velocity and acceleration terms to allow the consideration of wave kinematics. Resultant forces are defined and calculated for particular environmental conditions. Finally the results are interpreted to allow the estimation of lifetime loadings including peak loads and fatigue. The model is validated and a good correlation is found relative to standard BEMT. It is concluded that both a velocity gradient and a wave action may significantly reduce power output whilst increasing the loads on a system. It is also concluded that a 3 bladed rotor encounters far lower loadings than a 2 bladed equivalent over the device lifetime. It is also the intention of this study to compare and contrast various tidal stream turbine support structure concepts in terms of the suitability of each to withstand the lifetime loadings at reasonable cost. A number of support structure concepts are investigated from an impartial perspective. In conclusion there is not one concept which clearly surpasses the others in all areas

The iron electron-nuclear double resonance (ENDOR) of two-iron ferredoxins from spinach, parsley, pig adrenal cortex and Pseudomonas putida

The iron electron-nuclear double resonance (ENDOR) spectra of reduced iron-sulfur proteins (two-iron ferredoxins) from spinach, parsley, pig adrenal cortex and Pseudomonas putida unequivocally show two inequivalent iron atoms at the active sites of each of these proteins. The frequencies of the ENDOR lines establish the total electronic spin in the ground state to be . The principal values of the hyperfine tensor have been determined for each of the iron atoms and these values are consistent with and lend considerable support to the model of a high-spin Fe(III) atom and a high-spin Fe(II) atom antiferromagnetically coupled to form an system. The measured principal axis components of the effective hyperfine tensors for are as follows (1 and 2 refer to the inequivalent iron sites): These data are consistent with Site 1 being ferric and Site 2, ferrous iron. The primes indicate that the A-tensor principal axes for Site 1 (Fe(III)) are apparently rotated about the x-axis with respect to the g-tensor axes by an angle [theta] (20[deg] [les] [theta] [les] 40[deg]). The orientations of the A-tensors for Site 2 (Fe(II)) have not been determined and hence the values presented are the observed values of the A-tensors along the x, y, and z-axes of the g-tensor for this complex.A brief introduction to the theory of ENDOR is given.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/33533/1/0000032.pd

Biodiversity and resilience of ecosystem functions

Accelerating rates of environmental change and the continued loss of global biodiversity threaten functions and services delivered by ecosystems. Much ecosystem monitoring and management is focused on the provision of ecosystem functions and services under current environmental conditions, yet this could lead to inappropriate management guidance and undervaluation of the importance of biodiversity. The maintenance of ecosystem functions and services under substantial predicted future environmental change (i.e., their ‘resilience’) is crucial. Here we identify a range of mechanisms underpinning the resilience of ecosystem functions across three ecological scales. Although potentially less important in the short term, biodiversity, encompassing variation from within species to across landscapes, may be crucial for the longer-term resilience of ecosystem functions and the services that they underpin

A synthesis is emerging between biodiversity–ecosystem function and ecological resilience research: reply to Mori

Letter

Growing up beside you: a relational sociology of early childhood

This article will begin by outlining influential attempts by historians and sociologists to develop a more adequate theoretical understanding of past and contemporary childhoods, focusing on the major problems that stem from the pivotal role that ‘developmentalism’ plays in their arguments. I will argue that sociologists can overcome some of their deepest fears about the role of developmental psychology by developing a relational approach that integrates the biological and social aspects of children’s development. In the development of a relational sociology of early childhood we need to make important connections with closely related disciplines, but at the same time draw on and integrate research findings from relevant areas within the social and natural sciences. An alternative perspective drawn from the writings of Norbert Elias will be put forward and illustrated by discussing some of the key concepts that Elias and Vygotsky used to explain the language development of young children

Extinction filters mediate the global effects of habitat fragmentation on animals

Habitat loss is the primary driver of biodiversity decline worldwide, but the effects of fragmentation (the spatial arrangement of remaining habitat) are debated. We tested the hypothesis that forest fragmentation sensitivity—affected by avoidance of habitat edges—should be driven by historical exposure to, and therefore species’ evolutionary responses to disturbance. Using a database containing 73 datasets collected worldwide (encompassing 4489 animal species), we found that the proportion of fragmentation-sensitive species was nearly three times as high in regions with low rates of historical disturbance compared with regions with high rates of disturbance (i.e., fires, glaciation, hurricanes, and deforestation). These disturbances coincide with a latitudinal gradient in which sensitivity increases sixfold at low versus high latitudes. We conclude that conservation efforts to limit edges created by fragmentation will be most important in the world’s tropical forests

Btk regulates macrophage polarization in response to lipopolysaccharide

Bacterial Lipopolysaccharide (LPS) is a strong inducer of inflammation and does so by inducing polarization of macrophages to the classic inflammatory M1 population. Given the role of Btk as a critical signal transducer downstream of TLR4, we investigated its role in M1/M2 induction. In Btk deficient (Btk (−\−)) mice we observed markedly reduced recruitment of M1 macrophages following intraperitoneal administration of LPS. Ex vivo analysis demonstrated an impaired ability of Btk(−/−) macrophages to polarize into M1 macrophages, instead showing enhanced induction of immunosuppressive M2-associated markers in response to M1 polarizing stimuli, a finding accompanied by reduced phosphorylation of STAT1 and enhanced STAT6 phosphorylation. In addition to STAT activation, M1 and M2 polarizing signals modulate the expression of inflammatory genes via differential activation of transcription factors and regulatory proteins, including NF-κB and SHIP1. In keeping with a critical role for Btk in macrophage polarization, we observed reduced levels of NF-κB p65 and Akt phosphorylation, as well as reduced induction of the M1 associated marker iNOS in Btk(−/−) macrophages in response to M1 polarizing stimuli. Additionally enhanced expression of SHIP1, a key negative regulator of macrophage polarisation, was observed in Btk(−/−) macrophages in response to M2 polarizing stimuli. Employing classic models of allergic M2 inflammation, treatment of Btk (−/−) mice with either Schistosoma mansoni eggs or chitin resulted in increased recruitment of M2 macrophages and induction of M2-associated genes. This demonstrates an enhanced M2 skew in the absence of Btk, thus promoting the development of allergic inflammation

Effect of Deutetrabenazine on Chorea Among Patients With Huntington Disease A Randomized Clinical Trial

Importance Deutetrabenazine is a novel molecule containing deuterium, which attenuates CYP2D6 metabolism and increases active metabolite half-lives and may therefore lead to stable systemic exposure while preserving key pharmacological activity. Objective To evaluate efficacy and safety of deutetrabenazine treatment to control chorea associated with Huntington disease. Design, Setting, and Participants Ninety ambulatory adults diagnosed with manifest Huntington disease and a baseline total maximal chorea score of 8 or higher (range, 0-28; lower score indicates less chorea) were enrolled from August 2013 to August 2014 and randomized to receive deutetrabenazine (n = 45) or placebo (n = 45) in a double-blind fashion at 34 Huntington Study Group sites. Interventions Deutetrabenazine or placebo was titrated to optimal dose level over 8 weeks and maintained for 4 weeks, followed by a 1-week washout. Main Outcomes and Measures Primary end point was the total maximal chorea score change from baseline (the average of values from the screening and day-0 visits) to maintenance therapy (the average of values from the week 9 and 12 visits) obtained by in-person visits. This study was designed to detect a 2.7-unit treatment difference in scores. The secondary end points, assessed hierarchically, were the proportion of patients who achieved treatment success on the Patient Global Impression of Change (PGIC) and on the Clinical Global Impression of Change (CGIC), the change in 36-Item Short Form– physical functioning subscale score (SF-36), and the change in the Berg Balance Test. Results Ninety patients with Huntington disease (mean age, 53.7 years; 40 women [44.4%]) were enrolled. In the deutetrabenazine group, the mean total maximal chorea scores improved from 12.1 (95% CI, 11.2-12.9) to 7.7 (95% CI, 6.5-8.9), whereas in the placebo group, scores improved from 13.2 (95% CI, 12.2-14.3) to 11.3 (95% CI, 10.0-12.5); the mean between-group difference was –2.5 units (95% CI, –3.7 to –1.3) (P < .001). Treatment success, as measured by the PGIC, occurred in 23 patients (51%) in the deutetrabenazine group vs 9 (20%) in the placebo group (P = .002). As measured by the CGIC, treatment success occurred in 19 patients (42%) in the deutetrabenazine group vs 6 (13%) in the placebo group (P = .002). In the deutetrabenazine group, the mean SF-36 physical functioning subscale scores decreased from 47.5 (95% CI, 44.3-50.8) to 47.4 (44.3-50.5), whereas in the placebo group, scores decreased from 43.2 (95% CI, 40.2-46.3) to 39.9 (95% CI, 36.2-43.6), for a treatment benefit of 4.3 (95% CI, 0.4 to 8.3) (P = .03). There was no difference between groups (mean difference of 1.0 unit; 95% CI, –0.3 to 2.3; P = .14), for improvement in the Berg Balance Test, which improved by 2.2 units (95% CI, 1.3-3.1) in the deutetrabenazine group and by 1.3 units (95% CI, 0.4-2.2) in the placebo group. Adverse event rates were similar for deutetrabenazine and placebo, including depression, anxiety, and akathisia. Conclusions and Relevance Among patients with chorea associated with Huntington disease, the use of deutetrabenazine compared with placebo resulted in improved motor signs at 12 weeks. Further research is needed to assess the clinical importance of the effect size and to determine longer-term efficacy and safety

Significant benefits of AIP testing and clinical screening in familial isolated and young-onset pituitary tumors

Context Germline mutations in the aryl hydrocarbon receptor-interacting protein (AIP) gene are responsible for a subset of familial isolated pituitary adenoma (FIPA) cases and sporadic pituitary neuroendocrine tumors (PitNETs). Objective To compare prospectively diagnosed AIP mutation-positive (AIPmut) PitNET patients with clinically presenting patients and to compare the clinical characteristics of AIPmut and AIPneg PitNET patients. Design 12-year prospective, observational study. Participants & Setting We studied probands and family members of FIPA kindreds and sporadic patients with disease onset ≤18 years or macroadenomas with onset ≤30 years (n = 1477). This was a collaborative study conducted at referral centers for pituitary diseases. Interventions & Outcome AIP testing and clinical screening for pituitary disease. Comparison of characteristics of prospectively diagnosed (n = 22) vs clinically presenting AIPmut PitNET patients (n = 145), and AIPmut (n = 167) vs AIPneg PitNET patients (n = 1310). Results Prospectively diagnosed AIPmut PitNET patients had smaller lesions with less suprasellar extension or cavernous sinus invasion and required fewer treatments with fewer operations and no radiotherapy compared with clinically presenting cases; there were fewer cases with active disease and hypopituitarism at last follow-up. When comparing AIPmut and AIPneg cases, AIPmut patients were more often males, younger, more often had GH excess, pituitary apoplexy, suprasellar extension, and more patients required multimodal therapy, including radiotherapy. AIPmut patients (n = 136) with GH excess were taller than AIPneg counterparts (n = 650). Conclusions Prospectively diagnosed AIPmut patients show better outcomes than clinically presenting cases, demonstrating the benefits of genetic and clinical screening. AIP-related pituitary disease has a wide spectrum ranging from aggressively growing lesions to stable or indolent disease course