Differences in methylation profiles between HPV-positive and HPV-negative oropharynx squamous cell carcinoma

Oropharyngeal squamous cell carcinoma (OPSCC) is associated with human papillomavirus (HPV). HPV-positive OPSCC is considered a distinct molecular entity with a better prognosis than HPV-negative cases of OPSCC. However, the exact pathogenic mechanisms underlying the differences in clinical and molecular behavior between HPV-positive and HPV-negative OPSCC remain poorly understood. Epigenetic events play an important role in the development of cancer. Hypermethylation of DNA in promoter regions and global hypomethylation are 2 epigenetic changes that have been frequently observed in human cancers. It is suggested that heterogeneous epigenetic changes play a role in the clinical and biological differences between HPV-positive and HPV-negative tumors. Unraveling the differences in methylation profiles of HPV-associated OPSCC may provide for promising clinical applications and may pave the road for personalized cancer treatment. This systematic review aims to assess the current state of knowledge regarding differences in promoter hypermethylation and global methylation between HPV-positive and HPV-negative OPSCC.     

Testing small study effects in multivariate meta-analysis

Small study effects occur when smaller studies show different, often larger, treatment effects than large ones, which may threaten the validity of systematic reviews and meta-analyses. The most well-known reasons for small study effects include publication bias, outcome reporting bias, and clinical heterogeneity. Methods to account for small study effects in univariate meta-analysis have been extensively studied. However, detecting small study effects in a multivariate meta-analysis setting remains an untouched research area. One of the complications is that different types of selection processes can be involved in the reporting of multivariate outcomes. For example, some studies may be completely unpublished while others may selectively report multiple outcomes. In this paper, we propose a score test as an overall test of small study effects in multivariate meta-analysis. Two detailed case studies are given to demonstrate the advantage of the proposed test over various naive applications of univariate tests in practice. Through simulation studies, the proposed test is found to retain nominal Type I error rates with considerable power in moderate sample size settings. Finally, we also evaluate the concordance between the proposed tests with the naive application of univariate tests by evaluating 44 systematic reviews with multiple outcomes from the Cochrane Database.     

Relative efficiency of using summary versus individual data in random-effects meta-analysis

Meta-analysis is a statistical methodology for combining information from diverse sources so that a more reliable and efficient conclusion can be reached. It can be conducted by either synthesizing study-level summary statistics or drawing inference from an overarching model for individual participant data (IPD) if available. The latter is often viewed as the “gold standard.” For random-effects models, however, it remains not fully understood whether the use of IPD indeed gains efficiency over summary statistics. In this paper, we examine the relative efficiency of the two methods under a general likelihood inference setting. We show theoretically and numerically that summary-statistics-based analysis is at most as efficient as IPD analysis, provided that the random effects follow the Gaussian distribution, and maximum likelihood estimation is used to obtain summary statistics. More specifically, (i) the two methods are equivalent in an asymptotic sense; and (ii) summary-statistics-based inference can incur an appreciable loss of efficiency if the sample sizes are not sufficiently large. Our results are established under the assumption that the between-study heterogeneity parameter remains constant regardless of the sample sizes, which is different from a previous study. Our findings are confirmed by the analyses of simulated data sets and a real-world study of alcohol interventions.     

Process,correlation and parameter fitting in species distribution models: a response to Kriticos et al

In a recent article (Dormann et al., 2012, Journal of Biogeography, 39, 2119–2131), we compared different approaches to species distribution modelling and depicted modelling approaches along an axis from purely ‘correlative’ to ‘forward process‐based’ models. In their correspondence, Kriticos et al. (2013, Journal of Biogeography, doi: 10.1111/j.1365‐2699.2012.02791.x ) challenge this view, claiming that our continuum representation neglects differences among models and does not consider the ability of fitted process‐based models to combine the advantages of both process‐based and correlative modelling approaches. Here we clarify that the continuum view resulted from recognition of the manifold differences between models. We also reinforce the point that the current trend towards combining different modelling approaches may lead not only to the desired combination of the advantages but also to the accumulation of the disadvantages of those approaches. This point has not been made sufficiently clear previously.     

Relationship between virulence and aggressiveness in Plasmopara halstedii (sunflower downy mildew)

Relationship between virulence and aggressiveness was studied in seven Plasmopara halstedii (sunflower downy mildew) pathotypes including five progeny pathotypes of races 300, 304, 314, 704 and 714 arising from two parental pathotypes of races 100 and 710. Aggressiveness criteria including percentage infection, latent period, sporulation density and reduction of hypocotyl length were analysed in one sunflower inbred line showing a high level of quantitative resistance. There were significant differences between P. halstedii pathotypes for all aggressiveness criteria. Pathogenicity of progeny pathotypes as compared with parental ones (relationship between virulence and aggressiveness) seems to be positive, negative or uncorrelated. Hypothesis explaining these cases are discussed.     

Management of Sitotroga cerealella in stored cereal grains: a review

The economic loss due to pest attack in stored commodities is a serious problem worldwide. About 200 insect species attack stored commodities. These insect pests are responsible for quantitative and qualitative losses in cereal grains. Among the stored grain pests, Angoumois grain moth, Sitotroga cerealella is considered as common, top of the list and most destructive pest of cereal grains. Its infestation starts in the standing crop and continues in storage. Although there are many control strategies, our need is some effective, cheap and readily available strategy for safe storage. This review presents different ways by which S. cerealella can be controlled. In this paper, a list of approaches is given which are used to improve the protection of stored grains against S. cerealella attack. These approaches include use of edible oils, containers, synthetic chemicals, agricultural waste materials, plant derivatives, bacterial protoxins, biopesticides, biocontrol enhancers and semiochemicals. If these tactics are followed as combined strategies in a compatible manner, they can provide us an integrated pest management programme for the efficient control of S. cerealella in cereal grains.     

EDITORIAL

Olver, M. D. &; Kuyper, M. A. 1978. Breeding biology of the Whitebreasted Cormorant in Natal. Ostrich 49:25-30.

From 1972–1975 Whitebreasted Cormorants Phalacrocorax carbo bred at the Cedara Dam, Natal, South Africa (29 32S, 30 17E), and from 1973 they fished for food at Midmar Dam, 5 km away and carried the food back to the nestlings. Breeding occurred from April to October and was preceded by a period of courtship. Nesting material was collected by the males and the nests built by the females. The mean clutch size for 1972–1973 was 3,1. Both parents incubated the eggs and guarded the nest and chicks. Growth of the chicks was studied in 1972–1973. The mean number of chicks reared was 1,6 per nest although seven nests contained three nestlings. At 28 days they left the nest when alarmed, but could not fly until 49 days old. The average flying age appeared to be about 53 days. The height of the nests above the ground seemed to determine the nest leaving age. Of the 186 eggs laid in the 60 nests observed over two years, 74% hatched. Fledging success was 52% of eggs laid and 69% of eggs hatched. Chick mortality seemed to be caused mainly by falling from the nests and dying of starvation.     

Negotiating British Muslim belonging: a qualitative longitudinal study

British Muslims are often viewed as holding values incompatible with Britishness, regarded with suspicion and sometimes subjected to gendered forms of racism. Research projects have found that identifiably Muslim women face everyday microaggressions, yet little is known about how they negotiate both this and their identities over time. This article addresses this gap by reporting the results of qualitative longitudinal research that explores the narratives of two young British Muslim women over a seven-year period. The women were first interviewed when they were single undergraduates in 2010 and followed up as married young professionals in 2017. On both occasions they were negotiating their identities and sense of belonging in a climate of heightened scrutiny of Muslims. The paper examines their reflections on: “fitting in” with Britishness, their religious identities and the complexity of belonging. Methodologically, it contributes to qualitative longitudinal narrative research.