Summer weather becomes more persistent in a 2 °C world

Heat and rainfall extremes have intensified over the past few decades and this trend is projected to continue with future global warming1–3. A long persistence of extreme events often leads to societal impacts with warm-and-dry conditions severely affecting agriculture and consecutive days of heavy rainfall leading to flooding. Here we report systematic increases in the persistence of boreal summer weather in a multi-model analysis of a world 2 °C above pre-industrial compared to present-day climate. Averaged over the Northern Hemisphere mid-latitude land area, the probability of warm periods lasting longer than two weeks is projected to increase by 4% (2–6% full uncertainty range) after removing seasonal-mean warming. Compound dry–warm persistence increases at a similar magnitude on average but regionally up to 20% (11–42%) in eastern North America. The probability of at least seven consecutive days of strong precipitation increases by 26% (15–37%) for the mid-latitudes. We present evidence that weakening storm track activity contributes to the projected increase in warm and dry persistence. These changes in persistence are largely avoided when warming is limited to 1.5 °C. In conjunction with the projected intensification of heat and rainfall extremes, an increase in persistence can substantially worsen the effects of future weather extremes

Relevance similarity: an alternative means to monitor information retrieval systems

BACKGROUND: Relevance assessment is a major problem in the evaluation of information retrieval systems. The work presented here introduces a new parameter, "Relevance Similarity", for the measurement of the variation of relevance assessment. In a situation where individual assessment can be compared with a gold standard, this parameter is used to study the effect of such variation on the performance of a medical information retrieval system. In such a setting, Relevance Similarity is the ratio of assessors who rank a given document same as the gold standard over the total number of assessors in the group. METHODS: The study was carried out on a collection of Critically Appraised Topics (CATs). Twelve volunteers were divided into two groups of people according to their domain knowledge. They assessed the relevance of retrieved topics obtained by querying a meta-search engine with ten keywords related to medical science. Their assessments were compared to the gold standard assessment, and Relevance Similarities were calculated as the ratio of positive concordance with the gold standard for each topic. RESULTS: The similarity comparison among groups showed that a higher degree of agreements exists among evaluators with more subject knowledge. The performance of the retrieval system was not significantly different as a result of the variations in relevance assessment in this particular query set. CONCLUSION: In assessment situations where evaluators can be compared to a gold standard, Relevance Similarity provides an alternative evaluation technique to the commonly used kappa scores, which may give paradoxically low scores in highly biased situations such as document repositories containing large quantities of relevant data

A Preliminary Analysis of the Immunoglobulin Genes in the African Elephant (Loxodonta africana)

The genomic organization of the IgH (Immunoglobulin heavy chain), Igκ (Immunoglobulin kappa chain), and Igλ (Immunoglobulin lambda chain) loci in the African elephant (Loxodonta africana) was annotated using available genome data. The elephant IgH locus on scaffold 57 spans over 2,974 kb, and consists of at least 112 VH gene segments, 87 DH gene segments (the largest number in mammals examined so far), six JH gene segments, a single μ, a δ remnant, and eight γ genes (α and ε genes are missing, most likely due to sequence gaps). The Igκ locus, found on three scaffolds (202, 50 and 86), contains a total of 153 Vκ gene segments, three Jκ segments, and a single Cκ gene. Two different transcriptional orientations were determined for these Vκ gene segments. In contrast, the Igλ locus on scaffold 68 includes 15 Vλ gene segments, all with the same transcriptional polarity as the downstream Jλ-Cλ cluster. These data suggest that the elephant immunoglobulin gene repertoire is highly diverse and complex. Our results provide insights into the immunoglobulin genes in a placental mammal that is evolutionarily distant from humans, mice, and domestic animals

Assessors agreement: A case study across assessor type, payment levels, query variations and relevance dimensions

Relevance assessments are the cornerstone of Information Retrieval evaluation. Yet, there is only limited understanding of how assessment disagreement influences the reliability of the evaluation in terms of systems rankings. In this paper we examine the role of assessor type (expert vs. layperson), payment levels (paid vs. unpaid), query variations and relevance dimensions (topicality and understandability) and their influence on system evaluation in the presence of disagreements across assessments obtained in the different settings. The analysis is carried out in the context of the CLEF 2015 eHealth Task 2 collection and shows that disagreements between assessors belonging to the same group have little impact on evaluation. It also shows, however, that assessment disagreement found across settings has major impact on evaluation when topical relevance is considered, while it has no impact when understandability assessments are considered

Factors associated with topographic changes of the optic nerve head induced by acute intraocular pressure reduction in glaucoma patients

Purpose To investigate factors associated with changes in optic nerve head (ONH) topography after acute intraocular pressure (IOP) reduction in patients with primary open-angle glaucoma (POAG).Methods Untreated POAG patients (IOP >21 mm Hg) were prospectively enrolled. Systemic and ocular information were collected, including central corneal thickness (CCT) and corneal hysteresis (CH). All patients underwent confocal scanning laser ophthalmoscopy and tonometry (Goldmann) before and 1 h after pharmacological IOP reduction. the mean of three measurements was considered for analysis. Changes in each ONH topographic parameter were assessed (one eye was randomly selected), and those that changed significantly were correlated with patient's systemic and ocular characteristics.Results A total of 42 patients were included (mean age, 66.7 +/- 11.8 years). After a mean IOP reduction of 47.3 +/- 11.9%, significant changes were observed in cup area and volume, and in rim area and volume (P = 0.21, P = 0.12). Including all significant factors in a multivariable model, only the presence of diabetes remained significantly associated with all ONH parameters evaluated (P < 0.01).Conclusions Different systemic and ocular factors, such as diabetes, CH, and the relative size of the cup, seem to be associated with the magnitude of changes in ONH topography after acute IOP reduction in POAG patients. These associations partially explain the ONH changes observed in these patients and suggest that other factors are possibly implicated in an individual susceptibility to IOP. Eye (2011) 25, 201-207; doi:10.1038/eye.2010.179; published online 3 December 2010Universidade Federal de São Paulo, Dept Ophthalmol, BR-820 São Paulo, BrazilNew York Eye & Ear Infirm, Einhorn Clin Res Ctr, New York, NY 10003 USANew York Med Coll, Valhalla, NY 10595 USAUniversidade Federal de São Paulo, Dept Ophthalmol, BR-820 São Paulo, BrazilWeb of Scienc