Stellar Differential Rotation and Coronal Timescales

We investigate the timescales of evolution of stellar coronae in response to surface differential rotation and diffusion. To quantify this we study both the formation time and lifetime of a magnetic flux rope in a decaying bipolar active region. We apply a magnetic flux transport model to prescribe the evolution of the stellar photospheric field, and use this to drive the evolution of the coronal magnetic field via a magnetofrictional technique. Increasing the differential rotation (i.e. decreasing the equator-pole lap time) decreases the flux rope formation time. We find that the formation time is dependent upon the geometric mean of the lap time and the surface diffusion timescale. In contrast, the lifetime of flux ropes are proportional to the lap time. With this, flux ropes on stars with a differential rotation of more than eight times the solar value have a lifetime of less than two days. As a consequence, we propose that features such as solar-like quiescent prominences may not be easily observable on such stars, as the lifetimes of the flux ropes which host the cool plasma are very short. We conclude that such high differential rotation stars may have very dynamical coronae

Inferring kangaroo phylogeny from incongruent nuclear and mitochondrial genes

The marsupial genus Macropus includes three subgenera, the familiar large grazing kangaroos and wallaroos of M. (Macropus) and M. (Osphranter), as well as the smaller mixed grazing/browsing wallabies of M. (Notamacropus). A recent study of five concatenated nuclear genes recommended subsuming the predominantly browsing Wallabia bicolor (swamp wallaby) into Macropus. To further examine this proposal we sequenced partial mitochondrial genomes for kangaroos and wallabies. These sequences strongly favour the morphological placement of W. bicolor as sister to Macropus, although place M. irma (black-gloved wallaby) within M. (Osphranter) rather than as expected, with M. (Notamacropus). Species tree estimation from separately analysed mitochondrial and nuclear genes favours retaining Macropus and Wallabia as separate genera. A simulation study finds that incomplete lineage sorting among nuclear genes is a plausible explanation for incongruence with the mitochondrial placement of W. bicolor, while mitochondrial introgression from a wallaroo into M. irma is the deepest such event identified in marsupials. Similar such coalescent simulations for interpreting gene tree conflicts will increase in both relevance and statistical power as species-level phylogenetics enters the genomic age. Ecological considerations in turn, hint at a role for selection in accelerating the fixation of introgressed or incompletely sorted loci. More generally the inclusion of the mitochondrial sequences substantially enhanced phylogenetic resolution. However, we caution that the evolutionary dynamics that enhance mitochondria as speciation indicators in the presence of incomplete lineage sorting may also render them especially susceptible to introgression

Logics, rhetoric and 'the blob': populist logic in the Conservative reforms to English schooling

A lot has been written about the lasting implications of the Conservative reforms to English schooling, particularly changes made by Michael Gove as Education Secretary (2010–2014). There is a lot less work, however, on studying the role that language, strategy and the broader political framework played in the process of instituting and winning consent for these reforms. Studying these factors is important for ensuring that any changes to education and schooling are not read in isolation from their political context. Speeches particularly capture moments where intellectual and strategic political traditions meet, helping us to form a richer understanding of the motives behind specific reform goals and where they fit into a political landscape. This article analyses speeches and policy documents from prominent politicians who led the Conservative education agenda between 2010–2014 to illustrate how politicians mobilised a deliberate populist strategy and argumentation to achieve specific educational goals, but which have had broader social and political implications. Concepts from interpretive political studies are used to develop a case analysis of changes to teacher training provision and curriculum reform, illustrating how politicians constructed a frontier between ‘the people’ (commonly teachers or parents) and an illegitimate ‘elite’ (an educational establishment) that opposed change. This anti‐elite populist rhetoric, arguably first tested in the Department for Education, has now become instituted more widely in our current British politics

Survival of HIV-1 vertically infected children

PURPOSE OF REVIEW: It is 20 years since the start of the combination antiretroviral therapy (cART) era and more than 10 years since cART scale-up began in resource-limited settings. We examined survival of vertically HIV-infected infants and children in the cART era. RECENT FINDINGS: Good survival has been achieved on cART in all settings with up to 10-fold mortality reductions compared with before cART availability. Although mortality risk remains high in the first few months after cART initiation in young children with severe disease, it drops rapidly thereafter even for those who started with advanced disease, and longer term mortality risk is low. However, suboptimal retention on cART in routine programs threatens good survival outcomes and even on treatment children continue to experience high comorbidity risk; infections remain the major cause of death. Interventions to address infection risk include a cotrimoxazole prophylaxis, isoniazid preventive therapy, routine childhood and influenza immunization, and improving maternal survival. SUMMARY: Pediatric survival has improved substantially with cART and HIV-infected children are aging into adulthood. It is important to ensure access to diagnosis and early cART, good program retention as well as optimal comorbidity prophylaxis and treatment to achieve the best possible long-term survival and health outcomes for vertically infected children

Nuclear BK channels regulate CREB phosphorylation in RAW264.7 macrophages

BACKGROUND: Macrophages are important cells of the innate immune system and contribute to a variety of physiological and pathophysiological responses. Monovalent and divalent ion channels have been studied in macrophage function, and while much research is still required, a role for these channels is beginning to emerge in macrophages. In addition to the plasma membrane, ion channels are also found in intracellular membranes including mitochondrial, lysosomal and nuclear membranes. While studying the function of plasma membrane located large conductance voltage- and calcium-activated potassium channels (BK channels) in a macrophage cell line RAW264.7, we became aware of the expression of these ion channels in other cellular locations. METHODS: Immunofluorescence and Western blot analysis were used to identify the expression of BK channels. To demonstrate a functional role for the nuclear located channel, we investigated the effect of the lipid soluble BK channel inhibitor paxilline on CREB phosphorylation. RESULTS: Treatment of resting macrophages with paxilline resulted in increased CREB phosphorylation. To confirm a role for nuclear BK channels, these experiments were repeated in isolated nuclei and similar results were found. Ca2+ and calmodulin-dependent kinases (CaMK) have been demonstrated to regulate CREB phosphorylation. Inhibition of CaMKII and CaMKIV resulted in the reversal of paxilline-induced CREB phosphorylation. CONCLUSIONS: These results suggest that nuclear BK channels regulate CREB phosphorylation in macrophages. Nuclear located ion channels may therefore be part of novel signalling pathways in macrophages and should be taken into account when studying the role of ion channels in these and other cells

Programming Protocol-Independent Packet Processors

P4 is a high-level language for programming protocol-independent packet processors. P4 works in conjunction with SDN control protocols like OpenFlow. In its current form, OpenFlow explicitly specifies protocol headers on which it operates. This set has grown from 12 to 41 fields in a few years, increasing the complexity of the specification while still not providing the flexibility to add new headers. In this paper we propose P4 as a strawman proposal for how OpenFlow should evolve in the future. We have three goals: (1) Reconfigurability in the field: Programmers should be able to change the way switches process packets once they are deployed. (2) Protocol independence: Switches should not be tied to any specific network protocols. (3) Target independence: Programmers should be able to describe packet-processing functionality independently of the specifics of the underlying hardware. As an example, we describe how to use P4 to configure a switch to add a new hierarchical label

Geophysical characteristics and crustal structure of greenstone terranes: Canadian Shield

Geophysical studies in the Canadian Shield have provided some insights into the tectonic setting of greenstone belts. Greenstone belts are not rooted in deep crustal structures. Geophysical techniques consistently indicate that greenstones are restricted to the uppermost 10 km or so of crust and are underlain by geophysically normal crust. Gravity models suggest that granitic elements are similarly restricted, although magnetic modelling suggests possible downward extension to the intermediate discontinuity around approx. 18 km. Seismic evidence demonstrates that steeply-dipping structure, which can be associated with the belts in the upper crust, is not present in the lower crust. Horizontal intermediate discontinuities mapped under adjacent greenstone and granitic components are not noticeably disrupted in the boundary zone. Geophysical evidence points to the presence of discontinuities between greenhouse-granite and adjacent metasedimentary erranes. Measured stratigraphic thicknesses of greenstone belts are often twice or more the vertical thicknesses determined from gravity modelling. Explantations advanced for the discrepancy include stratigraphy repeated by thrust faulting and/or listric normal faulting, mechanisms which are consistent with certain aspects of conceptual models of greenstone development. Where repetition is not a factor the gravity evidence points to removal of the root zones of greenstone belts. For one region, this has been attributed to magmatic stopping during resurgent caldera activity

A convenient one-pot synthesis, and characterisation of the ω-bromo-1-(4-cyanobiphenyl-4’-yl) alkanes (CBnBr)

Open access via T&F agreementPeer reviewedPublisher PD

A multistage mathematical approach to automated clustering of high-dimensional noisy data

A critical problem faced in many scientific fields is the adequate separation of data derived from individual sources. Often, such datasets require analysis of multiple features in a highly multidimensional space, with overlap of features and sources. The datasets generated by simultaneous recording from hundreds of neurons emitting phasic action potentials have produced the challenge of separating the recorded signals into independent data subsets (clusters) corresponding to individual signal-generating neurons. Mathematical methods have been developed over the past three decades to achieve such spike clustering, but a complete solution with fully automated cluster identification has not been achieved. We propose here a fully automated mathematical approach that identifies clusters in multidimensional space through recursion, which combats the multidimensionality of the data. Recursion is paired with an approach to dimensional evaluation, in which each dimension of a dataset is examined for its informational importance for clustering. The dimensions offering greater informational importance are given added weight during recursive clustering. To combat strong background activity, our algorithm takes an iterative approach of data filtering according to a signal-to-noise ratio metric. The algorithm finds cluster cores, which are thereafter expanded to include complete clusters. This mathematical approach can be extended from its prototype context of spike sorting to other datasets that suffer from high dimensionality and background activity.National Institutes of Health (U.S.) (Grant R01 MH060379)United States. Defense Advanced Research Projects AgencyUnited States. Army Research Office (Grant W911NF-10-1-0059)Cure Huntington’s Disease Initiative, Inc. (Grant A-5552