Measuring Societal Biases in Text Corpora via First-Order Co-occurrence

Text corpora are used to study societal biases, typically through statistical models such as word embeddings. The bias of a word towards a concept is typically estimated using vectors similarity, measuring whether the word and concept words share other words in their contexts. We argue that this second-order relationship introduces unrelated concepts into the measure, which causes an imprecise measurement of the bias. We propose instead to measure bias using the direct normalized co-occurrence associations between the word and the representative concept words, a first-order measure, by reconstructing the co-occurrence estimates inherent in the word embedding models. To study our novel corpus bias measurement method, we calculate the correlation of the gender bias values estimated from the text to the actual gender bias statistics of the U.S. job market, provided by two recent collections. The results show a consistently higher correlation when using the proposed first-order measure with a variety of word embedding models, as well as a more severe degree of bias, especially to female in a few specific occupations

Ni vs. Pd in Suzuki-Miyaura sp2-sp2 cross-coupling : a head-to-head study in a comparable precatalyst/ligand system

We thank the University of St Andrews for a PhD studentship (MJW).The Suzuki-Miyaura reaction is a cornerstone method for sp2-sp2 cross-coupling in industry. There has been a concerted effort to enable the use of Ni catalysis as an alternative to Pd in order to mitigate cost and improve sustainability. Despite significant advances, ligand development for Ni-catalyzed Suzuki-Miyaura cross-coupling remains underdeveloped when compared to Pd and, as a consequence, ligands for Ni-catalyzed processes are typically taken from the Pd arena. In this study we evaluate the effect of using a similar Ni and Pd precatalyst based on a common bidentate ligand (dppf) in a head-to-head format for the most common type of biaryl couplings, establishing the practical implications of direct replacement of Pd with Ni, and identifying the potential origins of these observations in a mechanistic context.PostprintPeer reviewe

Investigating the links between meiotic chromosome structure and homologous recombination in Arabidopsis thaliana

Accurate chromosome segregation during meiosis requires the reciprocal exchange of DNA between homologous chromosomes, via a process called homologous recombination, resulting in the formation of crossovers (COs). This process begins with the formation of programmed DNA double-strand breaks (DSBs). Certain genomic loci, called hotspots, are more likely than others to produce DSBs. This is thought to be determined by various factors, which include post-translational histone modifications, such as H3K4 trimethylation. The histone methyl-transferase AtSDG2 is largely responsible for the deposition of this histone mark. This research shows that CO frequency and distribution are altered in an $Atsdg2$ background. Study of a mutant allele of a gene which codes for a subunit of a histone-acetyl transferase complex, called AtMRG2, revealed a strongly reduced fertility phenotype and failure to produce DSBs. Further study revealed that the defects were due to mutation to the $AtPRD3$ gene, known to be essential for DSB formation, and that the mutation to $AtMRG2$ was not responsible. During meiosis, homologous recombination takes place in the context of specific structural arrangement of DNA organised as an array of loops emanating out from a proteinaceous axis, a major component of which is AtASY1. My studies demonstrate that the dynamics of AtASY1 are affected by mutation to AtPCH2, an AAA+ ATPase, and that formation of the synaptonemal complex is perturbed. $Atpch2$mutants initiate DSB formation and CO designation normally, but defects occur in CO maturation, causing a reduced CO frequency and formation of univalent chromosomes at metaphase I. Finally, the effects of temperature on the structure of meiotic chromosomes and homologous recombination were studied by cytological analysis of Col 0 and different meiotic mutants subjected to a range of temperatures for the duration of meiosis. I have demonstrated that certain mutations, such as $Atsdg2$ and $Atpch2$, confer some resistance to the effects of high (32˚C) temperature treatment, which causes various meiotic defects in Col 0

Conceptual Design and Physical Model Tests of a Levee-in-Dune Hurricane Barrier

In an effort to protect the Greater Houston Metropolitan Area from hurricane storm surge damage, four Levee-in-Dune concepts are studied as part of the Ike Dike project. The Ike Dike is a proposed hurricane surge barrier developed by Dr. William Merrell at Texas A&M University at Galveston and is based on best practices developed by the Dutch. The project would span 62 mi including a levee system along the Galveston and Bolivar coasts, and a channel barrier across Bolivar Roads. This design study includes a homogeneous sand dune, and three dunes that each incorporate different protective cores: an armorstone revetment core, a clay levee core, and a concrete T-Wall core. The concepts undergo physical model tests that subject them to conditions that simulate 100-year storm damage caused by both surge and waves. Dune and beach morphology for each concept is measured through laser profiling techniques, and each concept is evaluated based on calculated erosion and accretion, as well as design considerations including cost. Wave conditions are measured by capacitance gauges at several locations. The Clay-Core and T-Wall concepts proved to be the most effective barriers against hurricane storm surge and wave protection based on their endurance during testing

Lactobacillus fermentum (PCC®) supplementation and gastrointestinal and respiratory-tract illness symptoms: a randomised control trial in athletes

BACKGROUND Probiotics purportedly reduce symptoms of gastrointestinal and upper respiratory-tract illness by modulating commensal microflora. Preventing and reducing symptoms of respiratory and gastrointestinal illness are the primary reason that dietary supplementation with probiotics are becoming increasingly popular with healthy active individuals. There is a paucity of data regarding the effectiveness of probiotics in this cohort. The aim of this study was to evaluate the effectiveness of a probiotic on faecal microbiology, self-reported illness symptoms and immunity in healthy well trained individuals. METHODS Competitive cyclists (64 males and 35 females; age 35 ± 9 and 36 ± 9 y, VO2max 56 ± 6 and 52 ± 6 ml.kg-1.min-1, mean ± SD) were randomised to either probiotic (minimum 1 × 109 Lactobacillus fermentum (PCC®) per day) or placebo treatment for 11 weeks in a double-blind, randomised, controlled trial. The outcome measures were faecal L. fermentum counts, self-reported symptoms of illness and serum cytokines. RESULTS Lactobacillus numbers increased 7.7-fold (90% confidence limits 2.1- to 28-fold) more in males on the probiotic, while there was an unclear 2.2-fold (0.2- to 18-fold) increase in females taking the probiotic. The number and duration of mild gastrointestinal symptoms were ~2-fold greater in the probiotic group. However, there was a substantial 0.7 (0.2 to 1.2) of a scale step reduction in the severity of gastrointestinal illness at the mean training load in males, which became more pronounced as training load increased. The load (duration×severity) of lower respiratory illness symptoms was less by a factor of 0.31 (99%CI; 0.07 to 0.96) in males taking the probiotic compared with placebo but increased by a factor of 2.2 (0.41 to 27) in females. Differences in use of cold and flu medication mirrored these symptoms. The observed effects on URTI had too much uncertainty for a decisive outcome. There were clear reductions in the magnitude of acute exercise-induced changes in some cytokines. CONCLUSION L. fermentum may be a useful nutritional adjunct for healthy exercising males. However, uncertainty in the effects of supplementation on URTI and on symptoms in females needs to be resolved. TRIAL REGISTRATION The trial was registered in the Australia and New Zealand Clinical Trials Registry (ACTRN12611000006943).The study was funded by Christian Hansen A/S, Probiomics and the Australian Institute of Sport

The Norumbega Fault Zone, Maine: a mid-to shallow-level crustal section within a transcurrent shear zone

From studies of structure, metamorphism, and geochronology we have evidence that the Norumbega Fault Zone represents a transition from mid- to shallow crustal levels in a dextral, transcurrent shear zone within the northern Appalachian Orogen. The Norumbega Fault Zone strikes parallel to the orogen (northeast-southwest), is ~5 to 30 km wide, and is characterized by distributed ductile dextral shear fabrics in the southwestern section with a transition to brittle fabrics toward the northeast. Within the zone of distributed shear, deformation is partitioned into local zones of very high strain. Upright, isoclinal folds are common in areas of high and low strain. Metamorphic grade decreases from amphibolite facies in the southwest to sub-green schist facies in the northeast. 40Ar/39Ar mineral ages from recrystallized minerals in a high strain zone, regional cooling ages in areas of lower strain, and metamorphic textures are consistent with a polyphase history of deformation. We interpret a younging trend in 40Ar/39Ar cooling ages toward the northeast, together with the deformational fabrics andmetamorphic features, to represent exhumation of the southwestern section of the Norumbega Fault Zone from mid-crustal levels during the polyphase history of this transcurrent zone. The Norumbega Fault Zone may therefore serve as a model for deformational processes at mid- to shallow crustal levels in active strike-slip systems. RÉSUMÉ Des études de la structure, du métamorphisme et de la géochronologic nous fournissent la preuve que la zone faillée de Norumbega représente une transition des niveaux crustaux moyens à des niveaux peu profonds dans une zone de cisaillement transversal dextrale à l'intérieur de la partie septentrionale de l'orogene appalachien. La zone faillée de Norumbega suit une direction paralléle a l'orogéne (nord-est-sud-ouest); die a cinq à 30 km de largeur; et elle est caractérisec par des structures cisaillées dextrales déformables se ramifiant dans la section sud-ouest avec une transition a des structures cassantes vers le nord-est. A l'intérieur de la zone de cisaillement ramifié, la déformation est divisée en zones locales de très forte contrainte. Les plis droits isoclinaux sont courants dans les secteurs de forte et faible contrainte. L'intensité du métamorphisme décroit d'un faciès à amphibolite dans le sud-ouest à un faciès secondaire de schistes verts dans le nord-est. Les périodes minérales 40Ar/39Ar des minéraux recristallises dans une zone de forte contrainte, les périodes de refroidissement régional dans les secteurs de faible contrainte et les textures métamorphiques correspondent à une orogénese polyphasée. Nous interprétons la tendance de rajeunissement dans les périodes de refroidissement 40Ar/39Ar vers le nord-est, de même que les textures de déformation et les caractéristiqucs métamorphiques, comme une exhumation de la section sud-ouest de la zone faillée de Norumbega depuis les niveaux crustaux moyens pendant l'histoire polyphasée de cette zone transversale. La zone faillée de Norumbega pourrait, par consequent, servir de modèle pour les processus de déformation aux niveaux variant de moyens à peu profonds dans les systèmes a décrochement. [Traduit par la rédaction

Persistent Magnetic Wreaths in a Rapidly Rotating Sun

When our Sun was young it rotated much more rapidly than now. Observations of young, rapidly rotating stars indicate that many possess substantial magnetic activity and strong axisymmetric magnetic fields. We conduct simulations of dynamo action in rapidly rotating suns with the 3-D MHD anelastic spherical harmonic (ASH) code to explore the complex coupling between rotation, convection and magnetism. Here we study dynamo action realized in the bulk of the convection zone for a system rotating at three times the current solar rotation rate. We find that substantial organized global-scale magnetic fields are achieved by dynamo action in this system. Striking wreaths of magnetism are built in the midst of the convection zone, coexisting with the turbulent convection. This is a surprise, for it has been widely believed that such magnetic structures should be disrupted by magnetic buoyancy or turbulent pumping. Thus, many solar dynamo theories have suggested that a tachocline of penetration and shear at the base of the convection zone is a crucial ingredient for organized dynamo action, whereas these simulations do not include such tachoclines. We examine how these persistent magnetic wreaths are maintained by dynamo processes and explore whether a classical mean-field $\alpha$-effect explains the regeneration of poloidal field.Comment: 17 pages, 9 figures, 1 appendix, emulateapj format; published version of sections 3-4, 7 and appendix from arXiv:0906.240

Naturallyoccurring differences in cenh3 affect chromosome segregation in zygotic mitosis of hybrids

The point of attachment of spindle microtubules to metaphase chromosomes is known as the centromere. Plant and animal centromeres are epigenetically specified by a centromere-specific variant of Histone H3, CENH3 (a.k.a. CENP-A). Unlike canonical histones that are invariant, CENH3 proteins are accumulating substitutions at an accelerated rate. This diversification of CENH3 is a conundrum since its role as the key determinant of centromere identity remains a constant across species. Here, we ask whether naturally occurring divergence in CENH3 has functional consequences. We performed functional complementation assays on cenh3-1, a null mutation in Arabidopsis thaliana, using untagged CENH3s from increasingly distant relatives. Contrary to previous results using GFP-tagged CENH3, we find that the essential functions of CENH3 are conserved across a broad evolutionary landscape. CENH3 from a species as distant as the monocot Zea mays can functionally replace A. thaliana CENH3. Plants expressing variant CENH3s that are fertile when selfed show dramatic segregation errors when crossed to a wild-type individual. The progeny of this cross include hybrid diploids, aneuploids with novel genetic rearrangements and haploids that inherit only the genome of the wild-type parent. Importantly, it is always chromosomes from the plant expressing the divergent CENH3 that missegregate. Using chimeras, we show that it is divergence in the fast-evolving N-terminal tail of CENH3 that is causing segregation errors and genome elimination. Furthermore, we analyzed N-terminal tail sequences from plant CENH3s and discovered a modular pattern of sequence conservation. From this we hypothesize that while the essential functions of CENH3 are largely conserved, the N-terminal tail is evolving to adapt to lineage-specific centromeric constraints. Our results demonstrate that this lineage-specific evolution of CENH3 causes inviability and sterility of progeny in crosses, at the same time producing karyotypic variation. Thus, CENH3 evolution can contribute to postzygotic reproductive barriers

Examination of the risk of reinfection with hepatitis C among injecting drug users who have been tested in Glasgow

Unsafe injecting practices put injecting drug users (IDUs) at repeat exposure to infection with the hepatitis C virus (HCV). It has not yet been determined if spontaneously clearing one's primary infection influences the risk of reinfection; our aim was to estimate the relative risk of reinfection in IDUs who have cleared the virus. We conducted a retrospective study using a large database of HCV test results covering Greater Glasgow Health Board during 1993–2007 to calculate rates of infection and reinfection in current/former IDUs. The relative risk of (re)infection in previously infected compared with never-infected IDUs was estimated using Poisson regression, adjusting for age at study entry, sex, and calendar period of test. Although the rate of reinfection in IDUs who were HCV antibody-positive, RNA-negative at baseline was lower (7/100 person-years, 95% CI: 5–9) than the rate of acute infection in IDUs who were HCV antibody-negative at baseline (10/100 person-years, 95% CI: 9–12), the risk of reinfection was not significantly different than the risk of initial infection (adjusted rate ratio = 0.78, 95% CI: 0.57–1.08). We found only weak evidence for a reduced risk of HCV reinfection in IDUs who had cleared their previous infection. Further research among those who have cleared infection through antiviral therapy is needed to help inform decisions regarding treatment of IDUs