The importance of artificial drains for macroinvertebrate biodiversity in reclaimed agricultural landscapes

Artificial drainage networks, ubiquitous within lowland agricultural landscapes in Europe and North America, exhibit a range of physical and chemical conditions, and may provide important habitat for aquatic organisms. Drains share hydromorphological characteristics with both lotic rivers and lentic ditches, potentially providing opportunities for a diverse range of taxa. However, little is known about the communities they support. A 23-year benthic macroinvertebrate dataset from four English catchments was used to determine the contributions of drains to biodiversity in a reclaimed agricultural landscape through a comparison of catchments, drain and river channels. A lack of significant differences in gamma diversity and high compositional overlap between rivers and drains showed that drains were not depauperate, and consistently contributed a richness comparable to that of rivers. High-compositional overlap suggested that drains from different catchments contributed comparably to aquatic biodiversity at the landscape scale. Significant differences in environmental conditions (inferred from biotic indices) between catchments may have marginally increased landscape gamma diversity through turnover. Despite similarities in community composition, non-native species were less abundant in drains. This study demonstrates the importance of drains for habitat provision in intensively farmed catchments, and highlights the need for focused research into their management and conservation potential

Electro-optically tunable microring resonators in lithium niobate

Optical microresonators have recently attracted a growing attention in the photonics community. Their applications range from quantum electro-dynamics to sensors and filtering devices for optical telecommunication systems, where they are likely to become an essential building block. The integration of nonlinear and electro-optical properties in the resonators represents a very stimulating challenge, as it would incorporate new and more advanced functionality. Lithium niobate is an excellent candidate material, being an established choice for electro-optic and nonlinear optical applications. Here we report on the first realization of optical microring resonators in submicrometric thin films of lithium niobate. The high index contrast films are produced by an improved crystal ion slicing and bonding technique using benzocyclobutene. The rings have radius R=100 um and their transmission spectrum has been tuned using the electro-optic effect. These results open new perspectives for the use of lithium niobate in chip-scale integrated optical devices and nonlinear optical microcavities.Comment: 15 pages, 8 figure

Oxygen-Enhanced MRI Accurately Identifies, Quantifies, and Maps Tumor Hypoxia in Preclinical Cancer Models.

There is a clinical need for noninvasive biomarkers of tumor hypoxia for prognostic and predictive studies, radiotherapy planning, and therapy monitoring. Oxygen-enhanced MRI (OE-MRI) is an emerging imaging technique for quantifying the spatial distribution and extent of tumor oxygen delivery in vivo. In OE-MRI, the longitudinal relaxation rate of protons (ΔR1) changes in proportion to the concentration of molecular oxygen dissolved in plasma or interstitial tissue fluid. Therefore, well-oxygenated tissues show positive ΔR1. We hypothesized that the fraction of tumor tissue refractory to oxygen challenge (lack of positive ΔR1, termed "Oxy-R fraction") would be a robust biomarker of hypoxia in models with varying vascular and hypoxic features. Here, we demonstrate that OE-MRI signals are accurate, precise, and sensitive to changes in tumor pO2 in highly vascular 786-0 renal cancer xenografts. Furthermore, we show that Oxy-R fraction can quantify the hypoxic fraction in multiple models with differing hypoxic and vascular phenotypes, when used in combination with measurements of tumor perfusion. Finally, Oxy-R fraction can detect dynamic changes in hypoxia induced by the vasomodulator agent hydralazine. In contrast, more conventional biomarkers of hypoxia (derived from blood oxygenation-level dependent MRI and dynamic contrast-enhanced MRI) did not relate to tumor hypoxia consistently. Our results show that the Oxy-R fraction accurately quantifies tumor hypoxia noninvasively and is immediately translatable to the clinic

HLA Immunogenotype Determines Persistent Human Papillomavirus Virus Infection in HIV-Infected Patients Receiving Antiretroviral Treatment

A proportion of human immunodeficiency virus (HIV)–infected patients develop persistent, stigmatizing human papillomavirus (HPV)–related cutaneous and genital warts and anogenital (pre)cancer. This is the first study to investigate immunogenetic variations that might account for HPV susceptibility and the largest to date to categorize the HPV types associated with cutaneous warts in HIV-positive patients. The HLA class I and II allele distribution was analyzed in 49 antiretroviral (ART)–treated HIV-positive patients with persistent warts, 42 noninfected controls, and 46 HIV-positive controls. The allele HLA-B*44 was more frequently identified in HIV-positive patients with warts (P = .004); a susceptible haplotype (HLA-B*44, HLA-C*05; P = .001) and protective genes (HLA-DQB1*06; P = .03) may also contribute. Cutaneous wart biopsy specimens from HIV-positive patients harbored common wart types HPV27/57, the unusual wart type HPV7, and an excess of Betapapillomavirus types (P = .002), compared with wart specimens from noninfected controls. These findings suggest that HLA testing might assist in stratifying those patients in whom vaccination should be recommended

Genes to predict VO2 max trainability: A systematic review

Cardiorespiratory fitness (VO2max) is an excellent predictor of chronic disease morbidity and mortality risk. Guidelines recommend individuals undertake exercise training to improve VO2max for chronic disease reduction. However, there are large inter-individual differences between exercise training responses. This systematic review is aimed at identifying genetic variants that are associated with VO2max trainability.Peer-reviewed research papers published up until October 2016 from four databases were examined. Articles were included if they examined genetic variants, incorporated a supervised aerobic exercise intervention; and measured VO2max/VO2peak pre and post-intervention.Thirty-five articles describing 15 cohorts met the criteria for inclusion. The majority of studies used a cross-sectional retrospective design. Thirty-two studies researched candidate genes, two used Genome-Wide Association Studies (GWAS), and one examined mRNA gene expression data, in addition to a GWAS. Across these studies, 97 genes to predict VO2max trainability were identified. Studies found phenotype to be dependent on several of these genotypes/variants, with higher responders to exercise training having more positive response alleles than lower responders (greater gene predictor score). Only 13 genetic variants were reproduced by more than two authors. Several other limitations were noted throughout these studies, including the robustness of significance for identified variants, small sample sizes, limited cohorts focused primarily on Caucasian populations, and minimal baseline data. These factors, along with differences in exercise training programs, diet and other environmental gene expression mediators, likely influence the ideal traits for VO2max trainability.Ninety-seven genes have been identified as possible predictors of VO2max trainability. To verify the strength of these findings and to identify if there are more genetic variants and/or mediators, further tightly-controlled studies that measure a range of biomarkers across ethnicities are required

Measures and models for causal inference in cross-sectional studies: arguments for the appropriateness of the prevalence odds ratio and related logistic regression

<p>Abstract</p> <p>Background</p> <p>Several papers have discussed which effect measures are appropriate to capture the contrast between exposure groups in cross-sectional studies, and which related multivariate models are suitable. Although some have favored the Prevalence Ratio over the Prevalence Odds Ratio -- thus suggesting the use of log-binomial or robust Poisson instead of the logistic regression models -- this debate is still far from settled and requires close scrutiny.</p> <p>Discussion</p> <p>In order to evaluate how accurately true causal parameters such as Incidence Density Ratio (IDR) or the Cumulative Incidence Ratio (CIR) are effectively estimated, this paper presents a series of scenarios in which a researcher happens to find a preset ratio of prevalences in a given cross-sectional study. Results show that, provided essential and non-waivable conditions for causal inference are met, the CIR is most often inestimable whether through the Prevalence Ratio or the Prevalence Odds Ratio, and that the latter is the measure that consistently yields an appropriate measure of the Incidence Density Ratio.</p> <p>Summary</p> <p>Multivariate regression models should be avoided when assumptions for causal inference from cross-sectional data do not hold. Nevertheless, if these assumptions are met, it is the logistic regression model that is best suited for this task as it provides a suitable estimate of the Incidence Density Ratio.</p

Constraints on profit income distribution and production efficiency in private ownership economies with Ramsey taxation

Author's draft published as discussion paper by University of Exeter Department of Economics. The original publication is available at www.springerlink.comIn economies with Ramsey taxation, decreasing returns to scale, and private ownership, we show that second-best production efficiency is desirable when the grouping of private firms induced by the profit taxation power of the government is at least as fine as the grouping of firms induced by the institutional rules of profit distribution in the economy. The classic results of Dasgupta and Stiglitz [1972] (of firm-specific profit taxation) and Diamond and Mirrlees [1971] and Guesnerie [1995] (of uniform one-hundred percent profit taxation) follow as special cases of our model. Moreover, second-best analysis shows that optimal profit taxation is a substitute for optimal intermediate input taxation. In smooth economies, proportional, lump-sum, and affine modes of profit taxation are equivalent. We rework Mirrlees [1972] counterexample, which is posed in the context of a non-smooth economy, to show that second-best production efficiency continues to remain desirable under an affine structure of profit taxation

A review of RCTs in four medical journals to assess the use of imputation to overcome missing data in quality of life outcomes

Background: Randomised controlled trials (RCTs) are perceived as the gold-standard method for evaluating healthcare interventions, and increasingly include quality of life (QoL) measures. The observed results are susceptible to bias if a substantial proportion of outcome data are missing. The review aimed to determine whether imputation was used to deal with missing QoL outcomes. Methods: A random selection of 285 RCTs published during 2005/6 in the British Medical Journal, Lancet, New England Journal of Medicine and Journal of American Medical Association were identified. Results: QoL outcomes were reported in 61 (21%) trials. Six (10%) reported having no missing data, 20 (33%) reported ≤ 10% missing, eleven (18%) 11%–20% missing, and eleven (18%) reported >20% missing. Missingness was unclear in 13 (21%). Missing data were imputed in 19 (31%) of the 61 trials. Imputation was part of the primary analysis in 13 trials, but a sensitivity analysis in six. Last value carried forward was used in 12 trials and multiple imputation in two. Following imputation, the most common analysis method was analysis of covariance (10 trials). Conclusion: The majority of studies did not impute missing data and carried out a complete-case analysis. For those studies that did impute missing data, researchers tended to prefer simpler methods of imputation, despite more sophisticated methods being available.The Health Services Research Unit is funded by the Chief Scientist Office of the Scottish Government Health Directorate. Shona Fielding is also currently funded by the Chief Scientist Office on a Research Training Fellowship (CZF/1/31)

A review of RCTs in four medical journals to assess the use of imputation to overcome missing data in quality of life outcomes

Peer reviewedPublisher PD

Serotonin Transporter Promoter Polymorphism Genotype Is Associated With Behavioral Disinhibition and Negative Affect in Children of Alcoholics

Serotonergic (5-HT) dysfunction has been implicated in the etiology of both behavioral disinhibition (BD) and negative affect (NA). This work extends our previous finding of relationships between whole blood 5-HT and both BD and NA in pubescent, but not prepubescent, children of alcoholics and continues examination of a hypothesized role of 5-HT dysfunction in alcoholism risk. The long and short (L and S) variants of the 5-HT transporter gene-linked polymorphic region (5-HTTLPR) are responsible for differing transcriptional efficiencies in 5-HT uptake. Although associations have been found between the SS 5-HTTLPR genotype and severe alcoholism and neuroticism, recent reports describe relationships between the LL genotype and both low level of response to alcohol and alcoholism diagnosis and a predominance of the LL genotype in early-onset alcoholics. Methods : This report is from an ongoing prospective study of the development of risk for alcoholism and other problematic outcomes in a sample of families classified by father's alcoholism subtype. This study examines relationships between 5-HTTLPR genotype and both child BD (Child Behavior Checklist Aggressive Behavior) and NA (Child Behavior Checklist Anxious/Depressed) in offspring from 47 families. Results : Results showed significantly higher levels of BD and NA in the 16 children with the LL genotype than the 46 SS or SL children. Conclusions : Behaviors of undercontrol, which occur at increased rates in children of alcoholics, may be genetically influenced through the regulation of the 5-HT transporter. Due to the small sample size and the preliminary nature of our findings, replication is necessary.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65855/1/j.1530-0277.2001.tb02302.x.pd