Phylogenetic Analysis of Staphylococcus aureus CC398 Reveals a Sub-Lineage Epidemiologically Associated with Infections in Horses

In the early 2000s, a particular MRSA clonal complex (CC398) was found mainly in pigs and pig farmers in Europe. Since then, CC398 has been detected among a wide variety of animal species worldwide. We investigated the population structure of CC398 through mutation discovery at 97 genetic housekeeping loci, which are distributed along the CC398 chromosome within 195 CC398 isolates, collected from various countries and host species, including humans. Most of the isolates in this collection were received from collaborating microbiologists, who had preserved them over years. We discovered 96 bi-allelic polymorphisms, and phylogenetic analyses revealed that an epidemic sub-clone within CC398 (dubbed 'clade (C)') has spread within and between equine hospitals, where it causes nosocomial infections in horses and colonises the personnel. While clade (C) was strongly associated with S. aureus from horses in veterinary-care settings (p = 2 × 10(-7)), it remained extremely rare among S. aureus isolates from human infections

Identities in context: how social class shapes inequalities in education

Educational inequalities between social classes are large and persistent in the UK. Students from economically disadvantaged backgrounds have much lower attainment and engage less with education than their peers. Although structural factors contribute significantly to these inequalities, social psychological processes also play a crucial but less visible role. We draw on the social identity approach to propose a new model of how social and cultural factors in the local educational context shape the meaning of people’s social class identities in ways that create and sustain inequalities. Our identities-in-context model brings into focus educational contexts in which lower-class people: are expected to perform badly; are not well represented in high status educational roles or institutions; and are negatively disposed towards education. We argue that, for lower-class people, these contexts ignite a sense of social identity threat and incompatibility between their background and doing well in education. These, in turn, lead to poorer educational outcomes. We propose ways in which our model can be used to inform social psychological interventions that aim to reduce educational inequalities between social classes

Environmental Factors Affecting Germination and Seedling Survival of Carolina Willow (Salix Caroliniana)

In recent decades, invasive shrubs have replaced herbaceous wetlands in many parts of the world. In Florida, the native shrub Salix caroliniana Michx. (Carolina willow) expanded its distribution throughout the upper St. Johns River, replacing herbaceous marshes with willow swamps. To identify ways to prevent its expansion, we experimentally tested the effects of watering regime, temperature, substrate, and seed source on willow germination and seedling survival. In growth chamber experiments, germination and survival were most affected by watering regime and were greatest in saturated, organic soils. Survival decreased with soil inundation and on drier, sandy soils. Variable texture and nutrient content in native soils had no differential effect on germination or survivability of willow. Time of seed production, seed source, and delay in watering significantly affected germination. Seed germination occurred quickly after being sown. However, seed viability declined just as quickly. Whenever a soil held sufficient water, especially through capillarity, seeds of Carolina willow germinated and survived well. Seasonal manipulation of water levels to flood marshes during seed-fall and to inundate willow seedlings provides managers with an effective strategy for reducing establishment of Carolina willow. © Society of Wetland Scientists 2014