1,436 research outputs found

    Magneto-acoustic wave propagation and mode conversion in a magnetic solar atmosphere: comparing results from the CO5BOLD code with ray theory

    Full text link
    We present simulations of magneto-acoustic wave propagation in a magnetic, plane-parallel stratified solar model atmosphere, employing the CO5BOLD-code. The tests are carried out for two models of the solar atmosphere, which are similar to the ones used by Cally (2007) and Schunker & Cally (2006). The two models differ only in the orientation of the magnetic field. A qualitative comparison shows good agreement between the numerical results and the results from ray theory. The tests are done in view of the application of the present numerical code for the computation of energy fluxes of propagating acoustic waves into a dynamically evolving magnetic solar atmosphere. For this, we consider waves with frequencies above the acoustic cut-off frequency.Comment: 4 pages, 4 figures, will appear in HELAS-IV Conference Proceedin

    An E box comprises a positional sensor for regional differences in skeletal muscle gene expression and methylation

    Get PDF
    AbstractTo dissect the molecular mechanisms conferring positional information in skeletal muscles, we characterized the control elements responsible for the positionally restricted expression patterns of a muscle-specific transgene reporter, driven by regulatory sequences from the MLC1/3 locus. These sequences have previously been shown to generate graded transgene expression in the segmented axial muscles and their myotomal precursors, fortuitously marking their positional address. An evolutionarily conserved E box in the MLC enhancer core, not recognized by MyoD, is a target for a nuclear protein complex, present in a variety of tissues, which includes Hox proteins and Zbu1, a DNA-binding member of the SW12/SNF2 gene family. Mutation of this E box in the MLC enhancer has only a modest positive effect on linked CAT gene expression in transfected muscle cells, but when introduced into transgenic mice the same mutation elevates CAT transgene expression in skeletal muscles, specifically releasing the rostral restriction on MLC-CAT transgene expression in the segmented axial musculature. Increased transgene activity resulting from the E box mutation in the MLC enhancer correlates with reduced DNA methylation of the distal transgenic MLC1 promoter as well as in the enhancer itself. These results identify an E box and the proteins that bind to it as a positional sensor responsible for regional differences in axial skeletal muscle gene expression and accessibility

    Housing and environment for young children during the pandemic: Families in Tower Hamlets community survey and panel findings

    Get PDF
    Discusses findings from UKRI funded study of Families in Tower Hamlets in relation to housing and environment during the Covid-19 pandemi

    The universal Glivenko-Cantelli property

    Full text link
    Let F be a separable uniformly bounded family of measurable functions on a standard measurable space, and let N_{[]}(F,\epsilon,\mu) be the smallest number of \epsilon-brackets in L^1(\mu) needed to cover F. The following are equivalent: 1. F is a universal Glivenko-Cantelli class. 2. N_{[]}(F,\epsilon,\mu)0 and every probability measure \mu. 3. F is totally bounded in L^1(\mu) for every probability measure \mu. 4. F does not contain a Boolean \sigma-independent sequence. It follows that universal Glivenko-Cantelli classes are uniformity classes for general sequences of almost surely convergent random measures.Comment: 26 page

    Arthroscopic washout of the knee: a procedure in decline.

    Get PDF
    BACKGROUND: Osteoarthritis (OA) of the knee is a chronic, progressive condition which often requires surgical intervention. The evidence for the benefits of arthroscopic debridement or washout for knee OA is weak and arthroscopy is currently only indicated in the UK if there is a history of mechanical locking of the knee. OBJECTIVES: To investigate whether there has been any change in the number of arthroscopies performed in the UK since the 2007 NICE guidance on knee arthroscopy and the 2008 Cochrane review of arthroscopic debridement for OA of the knee. METHODS: We interrogated data from the Hospital Episodes Statistics (HES) database with Office of Population Censuses and Surveys-4 (OPSC-4) codes pertaining to therapeutic endoscopic operations in the 60-74 year old and 75 and over age groups. RESULTS: The number of arthroscopic knee interventions in the UK decreased overall from 2000 to 2012, with arthroscopic irrigations decreasing the most by 39.6 per 100,000 population (80%). However, the number of arthroscopic meniscal resections increased by 105.3 per 100,000 (230%) population. These trends were mirrored in both the 60-74 and 75 and over age groups. CONCLUSIONS: Knee arthroscopy in the 60-74 and 75 and over age groups appears to be decreasing but there is still a large and increasing number of arthroscopic meniscal resections being performed

    Global effects of local sound-speed perturbations in the Sun: A theoretical study

    Full text link
    We study the effect of localized sound-speed perturbations on global mode frequencies by applying techniques of global helioseismology on numerical simulations of the solar acoustic wave field. Extending the method of realization noise subtraction (e.g. Hanasoge et al. 2007) to global modes and exploiting the luxury of full spherical coverage, we are able to achieve very highly resolved frequency differences that are used to study sensitivities and the signatures of the thermal asphericities. We find that (1) global modes are almost twice as sensitive to sound-speed perturbations at the bottom of the convection zone as in comparison to anomalies well in the radiative interior (râ‰Č0.55R⊙r\lesssim0.55 R_\odot), (2) the mm-degeneracy is lifted ever so slightly, as seen in the aa coefficients, and (3) modes that propagate in the vicinity of the perturbations show small amplitude shifts (∌0.5\sim 0.5%).Comment: Submitted to Solar Physic

    Different paths to the modern state in Europe: the interaction between domestic political economy and interstate competition

    Get PDF
    Theoretical work on state formation and capacity has focused mostly on early modern Europe and on the experience of western European states during this period. While a number of European states monopolized domestic tax collection and achieved gains in state capacity during the early modern era, for others revenues stagnated or even declined, and these variations motivated alternative hypotheses for determinants of fiscal and state capacity. In this study we test the basic hypotheses in the existing literature making use of the large date set we have compiled for all of the leading states across the continent. We find strong empirical support for two prevailing threads in the literature, arguing respectively that interstate wars and changes in economic structure towards an urbanized economy had positive fiscal impact. Regarding the main point of contention in the theoretical literature, whether it was representative or authoritarian political regimes that facilitated the gains in fiscal capacity, we do not find conclusive evidence that one performed better than the other. Instead, the empirical evidence we have gathered lends supports to the hypothesis that when under pressure of war, the fiscal performance of representative regimes was better in the more urbanized-commercial economies and the fiscal performance of authoritarian regimes was better in rural-agrarian economie
    • 

    corecore