76 research outputs found

    On the appearance of Eisenstein series through degeneration

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    Let Γ\Gamma be a Fuchsian group of the first kind acting on the hyperbolic upper half plane H\mathbb H, and let M=Γ\HM = \Gamma \backslash \mathbb H be the associated finite volume hyperbolic Riemann surface. If γ\gamma is parabolic, there is an associated (parabolic) Eisenstein series, which, by now, is a classical part of mathematical literature. If γ\gamma is hyperbolic, then, following ideas due to Kudla-Millson, there is a corresponding hyperbolic Eisenstein series. In this article, we study the limiting behavior of parabolic and hyperbolic Eisenstein series on a degenerating family of finite volume hyperbolic Riemann surfaces. In particular, we prove the following result. If γΓ\gamma \in \Gamma corresponds to a degenerating hyperbolic element, then a multiple of the associated hyperbolic Eisenstein series converges to parabolic Eisenstein series on the limit surface.Comment: 15 pages, 2 figures. This paper has been accepted for publication in Commentarii Mathematici Helvetic

    Development of a Prediction Model for Stress Fracture During an Intensive Physical Training Program:The Royal Marines Commandos

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    Background Stress fractures (SF) are one of the more severe overuse injuries in military training and therefore knowledge of potential risk factors is needed to assist in developing mitigating strategies. Purpose To develop a prediction model for risk of SF in Royal Marines (RM) recruits during an arduous military training program. Study Design Cohort study Methods 1,082 recruits (age range: 16-33 years) enrolled between September 2009 and July 2010, were prospectively followed through the 32-week RM training program. SF diagnosis was confirmed from a positive X-Ray or Magnetic Resonance Imaging (MRI) scan. Potential risk factors assessed at week-1 included recruit characteristics, anthropometric assessment, dietary supplement use, lifestyle habits, fitness assessment, blood samples, 25(OH)D, bone strength as measured by heel Broadband Ultrasound Attention (BUA), history of physical activity, and previous and current food intake. A logistic least absolute shrinkage selection operator (LASSO) regression with 10-fold cross-validation method was used to select potential predictors among 47 candidate variables. Model performance was assessed using measures of discrimination (c-index) and calibration. Bootstrapping was used for internal validation of the developed model and to quantify optimism. Results A total of 86 (8%) volunteer recruits presented with at least one SF during training. Twelve variables were identified as the most important risk factors of SF. Variables strongly associated with SF were age, body weight, pre-training weight bearing (WB) exercise, pre-training cycling and childhood intake of milk and milk products. The c-index for the prediction model was 0.73 (optimism-corrected c-index 0.68), which represents the model performance in future volunteers. Although 25(OH)D and VO2max had only a borderline statistical significant association with SF, the inclusion of these factors improved the performance of the model. Conclusion These findings will assist in identifying recruits at greater risk of SF during training, and support interventions to mitigate this injury risk. However, external validation of the model is still required.</p

    Origins of the Ambient Solar Wind: Implications for Space Weather

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    The Sun's outer atmosphere is heated to temperatures of millions of degrees, and solar plasma flows out into interplanetary space at supersonic speeds. This paper reviews our current understanding of these interrelated problems: coronal heating and the acceleration of the ambient solar wind. We also discuss where the community stands in its ability to forecast how variations in the solar wind (i.e., fast and slow wind streams) impact the Earth. Although the last few decades have seen significant progress in observations and modeling, we still do not have a complete understanding of the relevant physical processes, nor do we have a quantitatively precise census of which coronal structures contribute to specific types of solar wind. Fast streams are known to be connected to the central regions of large coronal holes. Slow streams, however, appear to come from a wide range of sources, including streamers, pseudostreamers, coronal loops, active regions, and coronal hole boundaries. Complicating our understanding even more is the fact that processes such as turbulence, stream-stream interactions, and Coulomb collisions can make it difficult to unambiguously map a parcel measured at 1 AU back down to its coronal source. We also review recent progress -- in theoretical modeling, observational data analysis, and forecasting techniques that sit at the interface between data and theory -- that gives us hope that the above problems are indeed solvable.Comment: Accepted for publication in Space Science Reviews. Special issue connected with a 2016 ISSI workshop on "The Scientific Foundations of Space Weather." 44 pages, 9 figure

    The Accidental Terrorist: Okhrana Connections to the Extreme-Right and the Attempt to Assassinate Sergei Witte in 1907

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    This article represents a case study in the relationship between the tsarist secret police (commonly known as the Okhrana in the West and okhranka in Russia) and acts of political terror perpetrated by the extreme-right in late imperial Russia. This specific case concerns the tangled web of conspiracy, propaganda and controversy that surrounded the attempted assassination of former-Chairman of the Council of Ministers, Sergei Witte, in 1907

    Efficacy of self-monitored blood pressure, with or without telemonitoring, for titration of antihypertensive medication (TASMINH4): an unmasked randomised controlled trial.

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    BACKGROUND: Studies evaluating titration of antihypertensive medication using self-monitoring give contradictory findings and the precise place of telemonitoring over self-monitoring alone is unclear. The TASMINH4 trial aimed to assess the efficacy of self-monitored blood pressure, with or without telemonitoring, for antihypertensive titration in primary care, compared with usual care. METHODS: This study was a parallel randomised controlled trial done in 142 general practices in the UK, and included hypertensive patients older than 35 years, with blood pressure higher than 140/90 mm Hg, who were willing to self-monitor their blood pressure. Patients were randomly assigned (1:1:1) to self-monitoring blood pressure (self-montoring group), to self-monitoring blood pressure with telemonitoring (telemonitoring group), or to usual care (clinic blood pressure; usual care group). Randomisation was by a secure web-based system. Neither participants nor investigators were masked to group assignment. The primary outcome was clinic measured systolic blood pressure at 12 months from randomisation. Primary analysis was of available cases. The trial is registered with ISRCTN, number ISRCTN 83571366. FINDINGS: 1182 participants were randomly assigned to the self-monitoring group (n=395), the telemonitoring group (n=393), or the usual care group (n=394), of whom 1003 (85%) were included in the primary analysis. After 12 months, systolic blood pressure was lower in both intervention groups compared with usual care (self-monitoring, 137·0 [SD 16·7] mm Hg and telemonitoring, 136·0 [16·1] mm Hg vs usual care, 140·4 [16·5]; adjusted mean differences vs usual care: self-monitoring alone, -3·5 mm Hg [95% CI -5·8 to -1·2]; telemonitoring, -4·7 mm Hg [-7·0 to -2·4]). No difference between the self-monitoring and telemonitoring groups was recorded (adjusted mean difference -1·2 mm Hg [95% CI -3·5 to 1·2]). Results were similar in sensitivity analyses including multiple imputation. Adverse events were similar between all three groups. INTERPRETATION: Self-monitoring, with or without telemonitoring, when used by general practitioners to titrate antihypertensive medication in individuals with poorly controlled blood pressure, leads to significantly lower blood pressure than titration guided by clinic readings. With most general practitioners and many patients using self-monitoring, it could become the cornerstone of hypertension management in primary care. FUNDING: National Institute for Health Research via Programme Grant for Applied Health Research (RP-PG-1209-10051), Professorship to RJM (NIHR-RP-R2-12-015), Oxford Collaboration for Leadership in Applied Health Research and Care, and Omron Healthcare UK

    Modelling Quasi-Periodic Pulsations in Solar and Stellar Flares

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    Observations of the Sun at Vacuum-Ultraviolet Wavelengths from Space. Part II: Results and Interpretations

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    The aesthetic outcome of surgical correction for sagittal synostosis can be reliably scored by a novel method of preoperative and postoperative visual assessment.

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    BACKGROUND: Aims of surgical correction for isolated sagittal synostosis are functional and aesthetic. Multiple surgical techniques exist; however, reliable assessment of aesthetic outcome is poorly documented, limiting direct comparisons. The pinched appearance of the temporal regions is particularly challenging to correct. A visual analogue scale was designed to grade skull shape in patients who had total or subtotal calvarial remodeling for isolated sagittal synostosis. METHODS: Twenty-two assessors graded preoperative and postoperative photographs from 42 consecutive cases of sagittal synostosis under a single surgeon. Five aspects were graded (i.e., narrow elongated skull, frontal bossing, temporal pinching, occipital bullet, and overall shape) from 0 (normal) to 100 (severe). Interobserver and intraobserver agreement were analyzed by calculating within-subject standard deviation, coefficient of variation, and intraclass correlation coefficient. Linear regression analysis determined predictors of outcome. RESULTS: Surgery improved outcome dramatically across all five aspects of skull shape, with a 72.6 to 76.4 percent decrease in severity score. Improvements in severity score were greater after total calvarial remodeling, and type of calvarial remodeling (total versus subtotal) was an independent predictor of outcome in all aspects of skull shape (p≤0.001). Temporal pinching was improved in a subset of patients who also had onlay bone grafts in this region. CONCLUSIONS: Calvarial remodeling is a powerful technique for improving skull shape. A panel can detect gross and subtle aesthetic changes after surgical correction of sagittal synostosis using a visual analogue scale, with moderate interobserver and intraobserver agreement. This provides a tool for future outcome assessment. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV
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