704 research outputs found
Scaling asymptotics for quantized Hamiltonian flows
In recent years, the near diagonal asymptotics of the equivariant components
of the Szeg\"{o} kernel of a positive line bundle on a compact symplectic
manifold have been studied extensively by many authors. As a natural
generalization of this theme, here we consider the local scaling asymptotics of
the Toeplitz quantization of a Hamiltonian symplectomorphism, and specifically
how they concentrate on the graph of the underlying classical map
Semiclassical almost isometry
Let M be a complex projective manifold, and L an Hermitian ample line bundle
on it. A fundamental theorem of Gang Tian, reproved and strengthened by
Zelditch, implies that the Khaeler form of L can be recovered from the
asymptotics of the projective embeddings associated to large tensor powers of
L. More precisely, with the natural choice of metrics the projective embeddings
associated to the full linear series |kL| are asymptotically symplectic, in the
appropriate rescaled sense. In this article, we ask whether and how this result
extends to the semiclassical setting. Specifically, we relate the Weinstein
symplectic structure on a given isodrastic leaf of half-weighted
Bohr-Sommerfeld Lagrangian submanifolds of M to the asymptotics of the the
pull-back of the Fubini-Study form under the semiclassical projective maps
constructed by Borthwick, Paul and Uribe.Comment: exposition improve
Meta-analysis: re-treatment of genotype I hepatitis C nonresponders and relapsers after failing interferon and ribavirin combination therapy
Aliment Pharmacol Ther 2010; 32: 969–983The efficacy of re-treating genotype I hepatitis C virus (HCV) patients who failed combination therapy with interferon/pegylated interferon (PEG-IFN) and ribavirin remains unclear.To quantify sustained virological response (SVR) rates with different re-treatment regimens through meta-analysis of randomized controlled trials (RCTs).Randomized controlled trials of genotype I HCV treatment failure patients that compared currently available re-treatment regimens were selected. Two investigators independently extracted data on patient population, methods and results. The pooled relative risk of SVR for treatment regimens was computed using a random effects model.Eighteen RCTs were included. In nonresponders to standard interferon/ribavirin, re-treatment with high-dose PEG-IFN combination therapy improved SVR compared with standard PEG-IFN combination therapy (RR = 1.49; 95% CI: 1.09–2.04), but SVR rates did not exceed 18% in most studies. In relapsers to standard interferon/ribavirin, re-treatment with high-dose PEG-IFN or prolonged CIFN improved SVR (RR = 1.57; 95% CI: 1.16–2.14) and achieved SVR rates of 43–69%.In genotype I HCV treatment failure patients who received combination therapy, re-treatment with high-dose PEG-IFN combination therapy is superior to re-treatment with standard combination therapy, although SVR rates are variable for nonresponders (≤18%) and relapsers (43–69%). Re-treatment may be appropriate for select patients, especially relapsers and individuals with bridging fibrosis or compensated cirrhosis.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/79170/1/j.1365-2036.2010.04427.x.pd
‘Doing’ health policy analysis: methodological and conceptual reflections and challenges
The case for undertaking policy analysis has been made by a number of scholars and practitioners. However, there has been much less attention given to how to do policy analysis, what research designs, theories or methods best inform policy analysis. This paper begins by looking at the health policy environment, and some of the challenges to researching this highly complex phenomenon. It focuses on research in middle and low income countries, drawing on some of the frameworks and theories, methodologies and designs that can be used in health policy analysis, giving examples from recent studies. The implications of case studies and of temporality in research design are explored. Attention is drawn to the roles of the policy researcher and the importance of reflexivity and researcher positionality in the research process. The final section explores ways of advancing the field of health policy analysis with recommendations on theory, methodology and researcher reflexivity
Liver and Intestine Transplantation in the United States, 1995–2004
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/74804/1/j.1600-6143.2006.01273.x.pd
Simple matrix models for random Bergman metrics
Recently, the authors have proposed a new approach to the theory of random
metrics, making an explicit link between probability measures on the space of
metrics on a Kahler manifold and random matrix models. We consider simple
examples of such models and compute the one and two-point functions of the
metric. These geometric correlation functions correspond to new interesting
types of matrix model correlators. We study a large class of examples and
provide in particular a detailed study of the Wishart model.Comment: 23 pages, IOP Latex style, diastatic function Eq. (22) and contact
terms in Eqs. (76, 95) corrected, typos fixed. Accepted to JSTA
Variations in pigment and carbohydrate content of gallbladder bile affect accurate quantitation of total protein when using the fluorescamine method
Background: Despite solute dilution and reduced total lipid concentrations, an unexplained increase in protein concentration has been reported to occur in the gallbladder bile of cholesterol gallstone patients. Methods: Solutes in gallbladder bile from gallstone-free controls and from four study groups were measured using standard methods. Total proteins were measured using amino acid analysis and a conventional fluorescamine method. Results: Bile salts and pigment content were greater in gallstone-free controls than in all other study groups, including morbidly obese gallstone-free subjects. Total biliary protein concentration, as determined by amino acid analysis in the gallstone-free control group was higher than in non-obese gallstone patients with multiple stones and in morbidly obese gallstone-free subjects. Total biliary proteins as measured with fluorescamine, however, did not show intergroup differences. A major problem of the conventional fluorescamine assay is shown to be an artefact arising from the high pigment content of the more concentrated samples. Conclusions: Very dilute gallbladder bile samples are often found in the presence of gallstone disease. This also occurs in morbidly obese subjects, even in the absence of gallstones. Although the contribution of protein secretion/absorption by the gallbladder can also be relevant, especially in the presence of morbid obesity, the protein concentration in gallbladder bile, when accurately measured, generally parallels the concentrations of non-absorbed biliary solutes, reflecting the efficiency of fluid absorption. Measurement of biliary proteins by the conventional fluorescamine method is unreliable in clinical studies in which intergroup differences in pigment content are commonly present
Complex zeros of real ergodic eigenfunctions
We determine the limit distribution (as ) of complex
zeros for holomorphic continuations \phi_{\lambda}^{\C} to Grauert tubes of
real eigenfunctions of the Laplacian on a real analytic compact Riemannian
manifold with ergodic geodesic flow. If is an
ergodic sequence of eigenfunctions, we prove the weak limit formula
\frac{1}{\lambda_j} [Z_{\phi_{j_k}^{\C}}] \to \frac{i}{\pi} \bar{\partial}
{\partial} |\xi|_g, where [Z_{\phi_{j_k}^{\C}}] is the current of
integration over the complex zeros and where is with respect
to the adapted complex structure of Lempert-Sz\"oke and Guillemin-Stenzel.Comment: Added some examples and references. Also added a new Corollary, and
corrected some typo
Adolescents’ responses to the promotion and flavouring of e-cigarettes
Objectives
The purpose of the study is to examine adolescents’ awareness of e-cigarette marketing and investigate the impact of e-cigarette flavour descriptors on perceptions of product harm and user image.
Methods
Data come from the 2014 Youth Tobacco Policy Survey, a cross-sectional in-home survey conducted with 11–16 year olds across the UK (n = 1205). Adolescents’ awareness of e-cigarette promotion, brands, and flavours was assessed. Perceptions of product harm, and likely user of four examples of e-cigarette flavours was also examined.
Results
Some participants had tried e-cigarettes (12 %) but regular use was low (2 %) and confined to adolescents who had also smoked tobacco. Most were aware of at least one promotional channel (82 %) and that e-cigarettes came in different flavours (69 %). Brand awareness was low. E-cigarettes were perceived as harmful (M = 3.54, SD = 1.19) but this was moderated by product flavours. Fruit and sweet flavours were perceived as more likely to be tried by young never smokers than adult smokers trying to quit (p < 0.001).
Conclusions
There is a need to monitor the impact of future market and regulatory change on youth uptake and perceptions of e-cigarettes
Outcome of sustained virological responders with histologically advanced chronic hepatitis C
Retrospective studies suggest that subjects with chronic hepatitis C and advanced fibrosis who achieve a sustained virological response (SVR) have a lower risk of hepatic decompensation and hepatocellular carcinoma (HCC). In this prospective analysis, we compared the rate of death from any cause or liver transplantation, and of liver-related morbidity and mortality, after antiviral therapy among patients who achieved SVR, virologic nonresponders (NR), and those with initial viral clearance but subsequent breakthrough or relapse (BT/R) in the HALT-C (Hepatitis C Antiviral Long-Term Treatment Against Cirrhosis) Trial. Laboratory and/or clinical outcome data were available for 140 of the 180 patients who achieved SVR. Patients with nonresponse (NR; n = 309) or who experienced breakthrough or relapse (BT/R; n = 77) were evaluated every 3 months for 3.5 years and then every 6 months thereafter. Outcomes included death, liver-related death, liver transplantation, decompensated liver disease, and HCC. Median follow-up for the SVR, BT/R, and NR groups of patients was 86, 85, and 79 months, respectively. At 7.5 years, the adjusted cumulative rate of death/liver transplantation and of liver-related morbidity/mortality in the SVR group (2.2% and 2.7%, respectively) was significantly lower than that of the NR group (21.3% and 27.2%, P < 0.001 for both) but not the BT/R group (4.4% and 8.7%). The adjusted hazard ratio (HR) for time to death/liver transplantation (HR = 0.17, 95% confidence interval [CI] = 0.06-0.46) or development of liver-related morbidity/mortality (HR = 0.15, 95% CI = 0.06-0.38) or HCC (HR = 0.19, 95% CI = 0.04-0.80) was significant for SVR compared to NR. Laboratory tests related to liver disease severity improved following SVR. Conclusion: Patients with advanced chronic hepatitis C who achieved SVR had a marked reduction in death/liver transplantation, and in liver-related morbidity/mortality, although they remain at risk for HCC. (H EPATOLOGY 2010;)Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/78047/1/23744_ftp.pd
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