546 research outputs found

    On unitarizability in the case of classical p-adic groups

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    In the introduction of this paper we discuss a possible approach to the unitarizability problem for classical p-adic groups. In this paper we give some very limited support that such approach is not without chance. In a forthcoming paper we shall give additional evidence in generalized cuspidal rank (up to) three.Comment: This paper is a merged and revised version of ealier preprints arXiv:1701.07658 and arXiv:1701.07662. The paper is going to appear in the Proceedings of the Simons Symposium on Geometric Aspects of the Trace Formul

    Macdonald Polynomials from Sklyanin Algebras: A Conceptual Basis for the pp-Adics-Quantum Group Connection

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    We establish a previously conjectured connection between pp-adics and quantum groups. We find in Sklyanin's two parameter elliptic quantum algebra and its generalizations, the conceptual basis for the Macdonald polynomials, which ``interpolate'' between the zonal spherical functions of related real and pp\--adic symmetric spaces. The elliptic quantum algebras underlie the ZnZ_n\--Baxter models. We show that in the n \air \infty limit, the Jost function for the scattering of {\em first} level excitations in the ZnZ_n\--Baxter model coincides with the Harish\--Chandra\--like cc\--function constructed from the Macdonald polynomials associated to the root system A1A_1. The partition function of the Z2Z_2\--Baxter model itself is also expressed in terms of this Macdonald\--Harish\--Chandra\ cc\--function, albeit in a less simple way. We relate the two parameters qq and tt of the Macdonald polynomials to the anisotropy and modular parameters of the Baxter model. In particular the pp\--adic ``regimes'' in the Macdonald polynomials correspond to a discrete sequence of XXZ models. We also discuss the possibility of ``qq\--deforming'' Euler products.Comment: 25 page

    Quantitative Assessment of Whole-Body Tumor Burden in Adult Patients with Neurofibromatosis

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    Patients with neurofibromatosis 1 (NF1), NF2, and schwannomatosis are at risk for multiple nerve sheath tumors and premature mortality. Traditional magnetic resonance imaging (MRI) has limited ability to assess disease burden accurately. The aim of this study was to establish an international cohort of patients with quantified whole-body internal tumor burden and to correlate tumor burden with clinical features of disease.We determined the number, volume, and distribution of internal nerve sheath tumors in patients using whole-body MRI (WBMRI) and three-dimensional computerized volumetry. We quantified the distribution of tumor volume across body regions and used unsupervised cluster analysis to group patients based on tumor distribution. We correlated the presence and volume of internal tumors with disease-related and demographic factors.WBMRI identified 1286 tumors in 145/247 patients (59%). Schwannomatosis patients had the highest prevalence of tumors (P = 0.03), but NF1 patients had the highest median tumor volume (P = 0.02). Tumor volume was unevenly distributed across body regions with overrepresentation of the head/neck and pelvis. Risk factors for internal nerve sheath tumors included decreasing numbers of café-au-lait macules in NF1 patients (P = 0.003) and history of skeletal abnormalities in NF2 patients (P = 0.09). Risk factors for higher tumor volume included female gender (P = 0.05) and increasing subcutaneous neurofibromas (P = 0.03) in NF1 patients, absence of cutaneous schwannomas in NF2 patients (P = 0.06), and increasing age in schwannomatosis patients (p = 0.10).WBMRI provides a comprehensive phenotype of neurofibromatosis patients, identifies distinct anatomic subgroups, and provides the basis for investigating molecular biomarkers that correlate with unique disease manifestations

    Association of Accelerometry-Measured Physical Activity and Cardiovascular Events in Mobility-Limited Older Adults: The LIFE (Lifestyle Interventions and Independence for Elders) Study.

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    BACKGROUND:Data are sparse regarding the value of physical activity (PA) surveillance among older adults-particularly among those with mobility limitations. The objective of this study was to examine longitudinal associations between objectively measured daily PA and the incidence of cardiovascular events among older adults in the LIFE (Lifestyle Interventions and Independence for Elders) study. METHODS AND RESULTS:Cardiovascular events were adjudicated based on medical records review, and cardiovascular risk factors were controlled for in the analysis. Home-based activity data were collected by hip-worn accelerometers at baseline and at 6, 12, and 24 months postrandomization to either a physical activity or health education intervention. LIFE study participants (n=1590; age 78.9±5.2 [SD] years; 67.2% women) at baseline had an 11% lower incidence of experiencing a subsequent cardiovascular event per 500 steps taken per day based on activity data (hazard ratio, 0.89; 95% confidence interval, 0.84-0.96; P=0.001). At baseline, every 30 minutes spent performing activities ≥500 counts per minute (hazard ratio, 0.75; confidence interval, 0.65-0.89 [P=0.001]) were also associated with a lower incidence of cardiovascular events. Throughout follow-up (6, 12, and 24 months), both the number of steps per day (per 500 steps; hazard ratio, 0.90, confidence interval, 0.85-0.96 [P=0.001]) and duration of activity ≥500 counts per minute (per 30 minutes; hazard ratio, 0.76; confidence interval, 0.63-0.90 [P=0.002]) were significantly associated with lower cardiovascular event rates. CONCLUSIONS:Objective measurements of physical activity via accelerometry were associated with cardiovascular events among older adults with limited mobility (summary score >10 on the Short Physical Performance Battery) both using baseline and longitudinal data. CLINICAL TRIAL REGISTRATION:URL: http://www.clinicaltrials.gov. Unique identifier: NCT01072500

    Framing interculturality: a corpus-based analysis of on-line promotional discourse of higher education intercultural communication courses

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    This paper examines how intercultural communication (ICC) and the notion of culture are framed in on-line promotional discourse of higher education intercultural communication courses. It analyses a specialised corpus comprised of 14,842 words from 43 course websites of master’s programmes in intercultural communication in the UK and the US—internationally, the two largest providers of such programmes. Through combining corpus tools with a ‘situated meaning’ approach, the analysis reveals that while a small number of courses acknowledge cultural ‘complexity’, culture is still very often reduced to an essentialised and static notion, despite growing criticism against such an approach in ICC literature. Intercultural communication is valorised as a combination of desirable skills and knowledge conducive to effective communication of different cultural groups and for those working in international arenas. Significant differences between the UK and US courses are identified with regard to the extent of associations with diversity-related social categories. The lack of interpretive, critical and constructivist positions on culture in promotional discourse is discussed in the context of neoliberal discourse and the current thinking towards professional competences dominant in Britain, North America, and other parts of the world

    Quantitative Assessment of Whole-Body Tumor Burden in Adult Patients with Neurofibromatosis

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    Purpose Patients with neurofibromatosis 1 (NF1), NF2, and schwannomatosis are at risk for multiple nerve sheath tumors and premature mortality. Traditional magnetic resonance imaging (MRI) has limited ability to assess disease burden accurately. The aim of this study was to establish an international cohort of patients with quantified whole-body internal tumor burden and to correlate tumor burden with clinical features of disease. Methods We determined the number, volume, and distribution of internal nerve sheath tumors in patients using whole-body MRI (WBMRI) and three-dimensional computerized volumetry. We quantified the distribution of tumor volume across body regions and used unsupervised cluster analysis to group patients based on tumor distribution. We correlated the presence and volume of internal tumors with disease-related and demographic factors. Results WBMRI identified 1286 tumors in 145/247 patients (59%). Schwannomatosis patients had the highest prevalence of tumors (P = 0.03), but NF1 patients had the highest median tumor volume (P = 0.02). Tumor volume was unevenly distributed across body regions with overrepresentation of the head/neck and pelvis. Risk factors for internal nerve sheath tumors included decreasing numbers of café-au-lait macules in NF1 patients (P = 0.003) and history of skeletal abnormalities in NF2 patients (P = 0.09). Risk factors for higher tumor volume included female gender (P = 0.05) and increasing subcutaneous neurofibromas (P = 0.03) in NF1 patients, absence of cutaneous schwannomas in NF2 patients (P = 0.06), and increasing age in schwannomatosis patients (p = 0.10). Conclusion WBMRI provides a comprehensive phenotype of neurofibromatosis patients, identifies distinct anatomic subgroups, and provides the basis for investigating molecular biomarkers that correlate with unique disease manifestations

    Coronary Artery Calcium Scores: Current Thinking and Clinical Applications

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    Most incident coronary disease occurs in previously asymptomatic individuals who were considered to be at a lower risk by traditional screening methods. There is a definite advantage if these individuals could be reclassified into a higher risk category, thereby impacting disease outcomes favorably. Coronary artery calcium scores have been recognized as an independent marker for adverse prognosis in coronary disease. Multiple population based studies have acknowledged the shortcomings of risk prediction models such as the Framingham risk score or the Procam score. The science behind coronary calcium is discussed briefly followed by a review of current thinking on calcium scores. An attempt has been made to summarize the appropriate indications and use of calcium scores

    Quality of life among parents of preterm infants: a scoping review

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    Purpose: To synthesize the body of knowledge on the factors influencing the QoL of mothers and fathers of preterm infants. Methods: A scoping review was performed. Publications indexed in PubMed®, Web of Science™, CINAHL® and PsycINFO® were searched, targeting studies presenting original empirical data that examined parental perception on QoL after a preterm delivery. Eligibility and data extraction were conducted by two independent researchers. The main quantitative findings were synthesized and qualitative data were explored by content analysis. Results: The studies, 11 quantitative and 1 mixed methods, were derived mainly from the USA (n = 6). Heterogeneity across the studies was observed regarding the operationalization of QoL and the use of units of analysis (mothers, parents, families and caregivers). In a context where 40 out of 45 covariates were analysed by only one or two studies, results suggested that parental QoL after a preterm delivery is influenced by factors related with mother’s characteristics, family issues and health care environment rather than infants’ variables. Factors regarding fathers’ characteristics and structural levels were not addressed. Conclusions: Standardizing the operationalization of the QoL when analysing mothers and fathers of preterm infants calls for a structured questionnaire adapted to their specific needs. Further research should include both mothers and fathers, invest in mixed methods approaches and be performed in different countries and settings for allowing integration and comparison of findings.This work was supported by FEDER funding from the Operational Programme Factors of Competitiveness—COMPETE and by national funding from the Foundation for Science and Technology—FCT (Portuguese Ministry of Science, Technology and Higher Education) under the project “Parenting roles and knowledge in Neonatal Intensive Care Units” (FCOMP-01-0124-FEDER-019902; Ref. FCT PTDC/CS-ECS/120750/2010) and the Unidade de Investigação em Epidemiologia—Instituto de Saúde Pública da Universidade do Porto (EPIUnit) (POCI-01-0145-FEDER-006862; Ref. UID/DTP/04750/2013); the grants PD/BD/105830/2014 (to MA), SFRH/BPD/103562/2014 (to EA), co-funded by the FCT and the POPH/FSE Program and the FCT Investigator contract IF/01674/2015 (to SS)
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