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
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
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
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
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.
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
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Phenotypic heterogeneity and genetic modification of P102L inherited prion disease in an international series
The largest kindred with inherited prion disease P102L, historically Gerstmann-StrÀussler-Scheinker syndrome, originates from central England, with émigrés now resident in various parts of the English-speaking world. We have collected data from 84 patients in the large UK kindred and numerous small unrelated pedigrees to investigate phenotypic heterogeneity and modifying factors. This collection represents by far the largest series of P102L patients so far reported. Microsatellite and genealogical analyses of eight separate European kindreds support multiple distinct mutational events at a cytosine-phosphate diester-guanidine dinucleotide mutation hot spot. All of the smaller P102L kindreds were linked to polymorphic human prion protein gene codon 129M and were not connected by genealogy or microsatellite haplotype background to the large kindred or each other. While many present with classical Gerstmann-StrÀussler-Scheinker syndrome, a slowly progressive cerebellar ataxia with later onset cognitive impairment, there is remarkable heterogeneity. A subset of patients present with prominent cognitive and psychiatric features and some have met diagnostic criteria for sporadic Creutzfeldt-Jakob disease. We show that polymorphic human prion protein gene codon 129 modifies age at onset: the earliest eight clinical onsets were all MM homozygotes and overall age at onset was 7 years earlier for MM compared with MV heterozygotes (P = 0.02). Unexpectedly, apolipoprotein E4 carriers have a delayed age of onset by 10 years (P = 0.02). We found a preponderance of female patients compared with males (54 females versus 30 males, P = 0.01), which probably relates to ascertainment bias. However, these modifiers had no impact on a semi-quantitative pathological phenotype in 10 autopsied patients. These data allow an appreciation of the range of clinical phenotype, modern imaging and molecular investigation and should inform genetic counselling of at-risk individuals, with the identification of two genetic modifiers
Global effects of local sound-speed perturbations in the Sun: A theoretical study
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
(), (2) the -degeneracy is lifted ever so slightly,
as seen in the coefficients, and (3) modes that propagate in the vicinity
of the perturbations show small amplitude shifts ().Comment: Submitted to Solar Physic
Different paths to the modern state in Europe: the interaction between domestic political economy and interstate competition
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
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The Cerebellar Cognitive Affective/Schmahmann Syndrome Scale in Spinocerebellar Ataxias.
The Cerebellar Cognitive Affective/Schmahmann Syndrome (CCAS) manifests as impaired executive control, linguistic processing, visual spatial function, and affect regulation. The CCAS has been described in the spinocerebellar ataxias (SCAs), but its prevalence is unknown. We analyzed results of the CCAS/Schmahmann Scale (CCAS-S), developed to detect and quantify CCAS, in two natural history studies of 309 individuals Symptomatic for SCA1, SCA2, SCA3, SCA6, SCA7, or SCA8, 26 individuals Pre-symptomatic for SCA1 or SCA3, and 37 Controls. We compared total raw scores, domain scores, and total fail scores between Symptomatic, Pre-symptomatic, and Control cohorts, and between SCA types. We calculated scale sensitivity and selectivity based on CCAS category designation among Symptomatic individuals and Controls, and correlated CCAS-S performance against age and education, and in Symptomatic patients, against genetic repeat length, onset age, disease duration, motor ataxia, depression, and fatigue. Definite CCAS was identified in 46% of the Symptomatic group. False positive rate among Controls was 5.4%. Symptomatic individuals had poorer global CCAS-S performance than Controls, accounting for age and education. The domains of semantic fluency, phonemic fluency, and category switching that tap executive function and linguistic processing consistently separated Symptomatic individuals from Controls. CCAS-S scores correlated most closely with motor ataxia. Controls were similar to Pre-symptomatic individuals whose nearness to symptom onset was unknown. The use of the CCAS-S identifies a high CCAS prevalence in a large cohort of SCA patients, underscoring the utility of the scale and the notion that the CCAS is the third cornerstone of clinical ataxiology
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