Large‐scale hydro‐climatology of the terrestrial Arctic drainage system

The large‐scale hydro‐climatology of the terrestrial Arctic drainage system is examined, focusing on the period 1960 onward. Special attention is paid to the Ob, Yenisey, Lena, and Mackenzie watersheds, which provide the bulk of freshwater discharge to the Arctic Ocean. Station data are used to compile monthly gridded time series of gauge‐corrected precipitation (P). Gridded time series of precipitation minus evapotranspiration (P−ET) are calculated from the moisture flux convergence using NCEP reanalysis data. Estimates of ET are obtained as a residual. Runoff (R) is obtained from available discharge records. For long‐term water‐year means, P−ET for the Yenisey, Lena, and Mackenzie watersheds is 16–20% lower than the observed runoff. In the Ob watershed, the two values agree within 9%. Given the uncertainties in P−ET, we consider the atmospheric and surface water budgets to be reasonably closed. Compared to the other three basins, the mean runoff ratio (R/P) is lower in the Ob watershed, consistent with the high fraction of annual precipitation lost through ET. All basins exhibit summer maxima in P and minima in P−ET. Summer P−ET in the Ob watershed is negative due to high ET rates. For large domains in northern Eurasia, about 25% of July precipitation is associated with the recycling of water vapor evapotranspirated within each domain. This points to a significant effect of the land surface on the hydrologic regime. Variability in P and P−ET has generally clear associations with the regional atmospheric circulation. A strong link with the Urals trough is documented for the Ob. Relationships with indices of the Arctic Oscillation and other teleconnections are generally weak. Water‐year time series of runoff and P−ET are strongly correlated in the Lena watershed only, reflecting extensive permafrost. Cold‐season runoff has increased in the Yenisey and Lena watersheds. This is most pronounced in the Yenisey watershed, where runoff has also increased sharply in spring, decreased in summer, but has increased for the year as a whole. The mechanisms for these changes are not entirely clear. While they fundamentally relate to higher air temperatures, increased winter precipitation, and strong summer drying, we speculate links with changes in active layer thickness and thawing permafrost

Live imaging of Drosophila gonad formation reveals roles for Six4 in regulating germline and somatic cell migration

<p>Abstract</p> <p>Background</p> <p>Movement of cells, either as amoeboid individuals or in organised groups, is a key feature of organ formation. Both modes of migration occur during <it>Drosophila </it>embryonic gonad development, which therefore provides a paradigm for understanding the contribution of these processes to organ morphogenesis. Gonads of Drosophila are formed from three distinct cell types: primordial germ cells (PGCs), somatic gonadal precursors (SGPs), and in males, male-specific somatic gonadal precursors (msSGPs). These originate in distinct locations and migrate to associate in two intermingled clusters which then compact to form the spherical primitive gonads. PGC movements are well studied, but much less is known of the migratory events and other interactions undergone by their somatic partners. These appear to move in organised groups like, for example, lateral line cells in zebra fish or <it>Drosophila </it>ovarian border cells.</p> <p>Results</p> <p>We have used time-lapse fluorescence imaging to characterise gonadal cell behaviour in wild type and mutant embryos. We show that the homeodomain transcription factor Six4 is required for the migration of the PGCs and the msSGPs towards the SGPs. We have identified a likely cause of this in the case of PGCs as we have found that Six4 is required for expression of <it>Hmgcr </it>which codes for HMGCoA reductase and is necessary for attraction of PGCs by SGPs. Six4 affects msSGP migration by a different pathway as these move normally in <it>Hmgcr </it>mutant embryos. Additionally, embryos lacking fully functional Six4 show a novel phenotype in which the SGPs, which originate in distinct clusters, fail to coalesce to form unified gonads.</p> <p>Conclusion</p> <p>Our work establishes the <it>Drosophila </it>gonad as a model system for the analysis of coordinated cell migrations and morphogenesis using live imaging and demonstrates that Six4 is a key regulator of somatic cell function during gonadogenesis. Our data suggest that the initial association of SGP clusters is under distinct control from the movements that drive gonad compaction.</p

The evolutionary costs of immunological maintenance and deployment

<p>Abstract</p> <p>Background</p> <p>The evolution of disease resistance and immune function may be limited if increased immunocompetence comes at the expense of other fitness-determining traits. Both the maintenance of an immune system and the deployment of an immune response can be costly, and the observed costs may be evaluated as either physiological or evolutionary in origin. Evolutionary costs of immunological maintenance are revealed as negative genetic correlations between immunocompetence and fitness in the absence of infection. Costs of deployment are most often studied as physiological costs associated with immune system induction, however, evolutionary costs of deployment may also be present if genotypes vary in the extent of the physiological cost experienced.</p> <p>Results</p> <p>In this study we analyzed evolutionary and physiological costs of immunity in two environments representing food-limited and food-unlimited conditions. Patterns of genetic variation were estimated in females from 40 'hemiclone families' isolated from a population of <it>D. melanogaster</it>. Phenotypes evaluated included fecundity, weight measures at different time periods and resistance to <it>Providencia rettgeri</it>, a naturally occurring Gram-negative pathogen of <it>D. melanogaster</it>. In the food-limited environment we found a negative genetic correlation between fecundity in the absence of infection and resistance, indicative of an evolutionary cost of maintenance. No such correlation was observed in the food-unlimited environment, and the slopes of these correlations significantly differed, demonstrating a genotype-by-environment interaction for the cost of maintenance. Physiological costs of deployment were also observed, but costs were primarily due to wounding. Deployment costs were slightly exaggerated in the food-limited environment. Evolutionary costs of immunological deployment on fecundity were not observed, and there was only marginally significant genetic variation in the cost expressed by changes in dry weight.</p> <p>Conclusion</p> <p>Our results suggest that the costs of immunity may be an important factor limiting the evolution of resistance in food-limited environments. However, the significant genotype-by-environment interaction for maintenance costs, combined with the observation that deployment costs were partially mitigated in the food-unlimited environment, emphasizes the importance of considering environmental variation when estimating patterns of genetic variance and covariance, and the dubious nature of predicting evolutionary responses to selection from quantitative genetic estimates carried out in a single environment.</p

Feasibility study of a randomised controlled trial to investigate the treatment of sarcoidosis-associated fatigue with methylphenidate (FaST-MP): a study protocol

Introduction: Fatigue is a frequent and troublesome manifestation of chronic sarcoidosis. This symptom can be debilitating and difficult to treat, with poor response to the treatment. Symptomatic management with neurostimulants, such as methylphenidate, is a possible treatment option. The use of such treatment strategies is not without precedent and has been trialled in cancer-related fatigue. Their use in sarcoidosis requires further evaluation before it can be recommended for clinical practice. Methods and analysis: The Fatigue and Sarcoidosis—Treatment with Methylphenidate study is a randomised, controlled, parallel-arm and feasibility trial of methylphenidate for the treatment of sarcoidosis-associated fatigue. Patients are eligible if they have a diagnosis of sarcoidosis, significant fatigue (measured using the Fatigue Assessment Scale) and have stable disease. Up to 30 participants will be randomly assigned to either methylphenidate (20 mg two times per day) or identical placebo in a 3:2 ratio for 24 weeks. The primary objective is to collect data determining the feasibility of a future study powered to determine the clinical efficacy of methylphenidate for sarcoidosis-associated fatigue. The trial is presently open and will continue until July 2018. Ethics and dissemination: Ethical approval for the study was granted by the Cambridge Central Research Ethics Committee on 21 June 2016 (reference 16/EE/0087) and was approved and sponsored by the Norfolk and Norwich University Hospital (reference 190280). Clinical Trial Authorisation (EudraCT number 2016-000342-60) from the Medicines and Healthcare products Regulatory Agency (MHRA) was granted on 19 April 2016. Results will be presented at relevant conferences and submitted to appropriate journals following trial closure and analysis

Share capitalism and worker wellbeing

We show that worker wellbeing is determined not only by the amount of compensation workers receive but also by how compensation is determined. While previous theoretical and empirical work has often been preoccupied with individual performance-related pay, we find that the receipt of a range of group-performance schemes (profit shares, group bonuses and share ownership) is associated with higher job satisfaction. This holds conditional on wage levels, so that pay methods are associated with greater job satisfaction in addition to that coming from higher wages. We use a variety of methods to control for unobserved individual and job-specific characteristics. We suggest that half of the share-capitalism effect is accounted for by employees reciprocating for the “gift” we also show that share capitalism helps dampen the negative wellbeing effects of what we typically think of as “bad” aspects of job quality

Survival After Endovascular Aneurysm Sealing Compared With Endovascular Aneurysm Repair

Introduction Endovascular aneurysm sealing (EVAS) is a sac-filling device with a blunted systemic inflammatory response compared to conventional endovascular aneurysm repair (EVAR), with a suggested impact on all-cause mortality. This study compares mortality after both EVAS and EVAR. Materials and Methods This is a retrospective observational study including data from 2 centres, with ethical approval. Elective procedures on asymptomatic infrarenal aneurysms performed between January 2011 until April 2018 were enrolled. Laboratory values (serum creatinine, haemoglobin, white blood cell count, platelet count) were measured pre- and postoperatively and at 1 and 2 years, respectively. Mortality and cause of death were recorded during follow-up. Results A total of 564 patients were included (225 EVAS, 369 EVAR), after propensity score matching there were 207 patients in both groups. Baseline characteristics were similar, except for larger neck angulation and more pulmonary disease in the EVAR group. The median follow-up time was 49 (EVAS) and 44 (EVAR) months. No significant differences regarding creatinine and haemoglobin were observed. Preoperative white blood cell count was higher in the EVAR group (p=0.011), without significant differences during follow-up. Median platelet count was lower in the EVAR group preoperatively (p=0.001), but was significantly higher at 1 year follow-up (p=0.003). There were 43 deaths within the EVAS group (20.8%) and 52 within the EVAR group (25.1%) (p=0.293). Of these, 4 were aneurysm related (EVAS n=3, EVAR n=1; p=0.222) and 14 cardiovascular (EVAS n=6, EVAR n=8, p=0.845). For the EVAS cohort, survival was 95.5% at 1 year and 74.9% at 5 years. For the EVAR cohort, this was 93.3% at 1 year and 75.5% at 5 years. No significant differences were observed in causes of death. Conclusion This study showed comparable survival rates through 5 years between EVAS and EVAR with a tendency toward higher inflammatory response in the EVAR patients through the first 2 years