3,562 research outputs found

    Trends in colorectal cancer among Hispanics by stage and subsite location: 1989-2006

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    This is the final version of the article. Available from Springer Nature via the DOI in this record.OBJECTIVES: Hispanic colorectal cancer (CRC) rates historically have been lower than for non-Hispanic Whites in the United States and in Florida. The aim of this study is to understand CRC trends in Florida Hispanics and non-Hispanic Whites. METHODS: Using a cross-sectional study design, all invasive CRCs diagnosed among Florida residents between 1989 and 2006 were accessed from the Florida Cancer Data System (FCDS). These cases were analyzed by Hispanic and non-Hispanic White ethnic identification. The Hispanic Origin Identification Algorithm was applied to the FCDS data to identify Hispanic subjects. Primary cancer site and histology data were organized according to SEER (Surveillance Epidemiology and End Results) categories. Joinpoint regression was used to generate incidence trends by stage and subsite location. RESULTS: Rates of CRC incidence were higher for Florida Hispanics compared with non-Hispanic Whites since the mid 1990s. There was a consistent significant increase in the incidence of distant stage CRC in Hispanics (annual percent change (APC) of 1.26 and 0.90 in males and females), whereas rates in non-Hispanics decreased significantly during the same time period (APC -1.36 and -1.28, respectively). Similar trends were found in distant-stage right-sided CRC. Among right-sided CRCs, local stage incidence rate increased for both non-Hispanic Whites and Hispanics, whereas the incidence rate for regional stage decreased for both racial/ethnic groups. CONCLUSIONS: Trends for distant-stage CRC are increasing among Florida Hispanics. This is a particular public health concern given that CRC is a cancer for which screening modalities exist and could imply a concomitant increase in CRC-related mortality among Florida Hispanics. Lower rates of CRC screening in Hispanics are documented at the state level, relative to non-Hispanic Whites. Screening programs targeting the Florida Hispanic population are warranted.This work was supported by the Florida Department of Health (contract CODM7); the Florida Bankhead-Coley Cancer Research Program (#2BT02); the Centers for Disease Control and Prevention National Program of Cancer Registries; the Sylvester Comprehensive Cancer Center at the University of Miami Miller School of Medicine; and the European Regional Development Fund (ERDF) to University of Exeter

    Acute high-intensity interval running increases markers of damage and permeability but not gastrointestinal symptoms.

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    Purpose: To investigate the effects of high-intensity interval (HIIT) running on markers of gastrointestinal (GI) damage and permeability alongside subjective symptoms of GI discomfort. Methods: Eleven male runners completed an acute bout of HIIT (eighteen 400 m runs at 120%O2max ) where markers of GI permeability, intestinal damage and GI discomfort symptoms were assessed and compared with resting conditions. Results: Compared to rest, HIIT significantly increased serum lactulose:rhamnose ratio (0.051 ± 0.016 vs. 0.031 ± 0.021, p = 0.0047; 95% CI = 0.006 - 0.036) and sucrose concentrations (0.388 ± 0.217 vs 0.137 ± 0.148 mg.l-1; p < 0.001; 95% CI = 0.152 - 0.350). In contrast, urinary lactulose:rhamnose (0.032 ± 0.005 vs 0.030 ± 0.005; p = 0.3; 95% CI = -0.012 - 0.009) or sucrose concentrations (0.169 ± 0.168% vs 0.123 ± 0.120%; p = 0.54; 95% CI = -0.199 - 0.108) did not differ between HIIT and resting conditions. Plasma I-FABP was significantly increased (p < 0.001) during and in the recovery period from HIIT whereas no changes were observed during rest. Mild-symptoms of GI discomfort, were reported immediately- and 24 h post-HIIT, although these symptoms did not correlate to GI permeability or I-FABP. Conclusion Acute HIIT increased GI permeability and intestinal I-FABP release, although these do not correlate with symptoms of GI discomfort. Furthermore, by using serum sampling, we provide data showing that it is possible to detect changes in intestinal permeability that is not observed using urinary sampling over a shorter time-period

    Hamilton Jacobi Bellman equations in infinite dimensions with quadratic and superquadratic Hamiltonian

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    We consider Hamilton Jacobi Bellman equations in an inifinite dimensional Hilbert space, with quadratic (respectively superquadratic) hamiltonian and with continuous (respectively lipschitz continuous) final conditions. This allows to study stochastic optimal control problems for suitable controlled Ornstein Uhlenbeck process with unbounded control processes

    On Exceptional Times for generalized Fleming-Viot Processes with Mutations

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    If Y\mathbf Y is a standard Fleming-Viot process with constant mutation rate (in the infinitely many sites model) then it is well known that for each t>0t>0 the measure Yt\mathbf Y_t is purely atomic with infinitely many atoms. However, Schmuland proved that there is a critical value for the mutation rate under which almost surely there are exceptional times at which Y\mathbf Y is a finite sum of weighted Dirac masses. In the present work we discuss the existence of such exceptional times for the generalized Fleming-Viot processes. In the case of Beta-Fleming-Viot processes with index α]1,2[\alpha\in\,]1,2[ we show that - irrespectively of the mutation rate and α\alpha - the number of atoms is almost surely always infinite. The proof combines a Pitman-Yor type representation with a disintegration formula, Lamperti's transformation for self-similar processes and covering results for Poisson point processes

    Uniqueness Results for Second Order Bellman-Isaacs Equations under Quadratic Growth Assumptions and Applications

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    In this paper, we prove a comparison result between semicontinuous viscosity sub and supersolutions growing at most quadratically of second-order degenerate parabolic Hamilton-Jacobi-Bellman and Isaacs equations. As an application, we characterize the value function of a finite horizon stochastic control problem with unbounded controls as the unique viscosity solution of the corresponding dynamic programming equation

    Characterization, crystallization and preliminary X-ray investigation of glyceraldehyde-3-phosphate dehydrogenase from the hyperthermophilic archaeon Sulfolobus solfataricus.

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    Comparative StudyJournal ArticleResearch Support, Non-U.S. Gov'tRecombinant Sulfolobus solfataricus glyceraldehyde-3-phosphate dehydrogenase has been purified and found to be a tetramer of 148 kDa. The enzyme shows dual cofactor specificity and uses NADP+ in preference to NAD+. The sequence has been compared with other GAPDH proteins including those from other archaeal sources. The purified protein has been crystallized from ammonium sulfate to produce crystals that diffract to 2.4 A with a space group of P43212 or P41212. A native data set has been collected to 2.4 A using synchrotron radiation and cryocooling.European UnionBBSR

    An Optimal Execution Problem with Market Impact

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    We study an optimal execution problem in a continuous-time market model that considers market impact. We formulate the problem as a stochastic control problem and investigate properties of the corresponding value function. We find that right-continuity at the time origin is associated with the strength of market impact for large sales, otherwise the value function is continuous. Moreover, we show the semi-group property (Bellman principle) and characterise the value function as a viscosity solution of the corresponding Hamilton-Jacobi-Bellman equation. We introduce some examples where the forms of the optimal strategies change completely, depending on the amount of the trader's security holdings and where optimal strategies in the Black-Scholes type market with nonlinear market impact are not block liquidation but gradual liquidation, even when the trader is risk-neutral.Comment: 36 pages, 8 figures, a modified version of the article "An optimal execution problem with market impact" in Finance and Stochastics (2014

    Some flows in shape optimization

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    Geometric flows related to shape optimization problems of Bernoulli type are investigated. The evolution law is the sum of a curvature term and a nonlocal term of Hele-Shaw type. We introduce generalized set solutions, the definition of which is widely inspired by viscosity solutions. The main result is an inclusion preservation principle for generalized solutions. As a consequence, we obtain existence, uniqueness and stability of solutions. Asymptotic behavior for the flow is discussed: we prove that the solutions converge to a generalized Bernoulli exterior free boundary problem

    Differentiability of backward stochastic differential equations in Hilbert spaces with monotone generators

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    The aim of the present paper is to study the regularity properties of the solution of a backward stochastic differential equation with a monotone generator in infinite dimension. We show some applications to the nonlinear Kolmogorov equation and to stochastic optimal control

    The Stochastic Reach-Avoid Problem and Set Characterization for Diffusions

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    In this article we approach a class of stochastic reachability problems with state constraints from an optimal control perspective. Preceding approaches to solving these reachability problems are either confined to the deterministic setting or address almost-sure stochastic requirements. In contrast, we propose a methodology to tackle problems with less stringent requirements than almost sure. To this end, we first establish a connection between two distinct stochastic reach-avoid problems and three classes of stochastic optimal control problems involving discontinuous payoff functions. Subsequently, we focus on solutions of one of the classes of stochastic optimal control problems---the exit-time problem, which solves both the two reach-avoid problems mentioned above. We then derive a weak version of a dynamic programming principle (DPP) for the corresponding value function; in this direction our contribution compared to the existing literature is to develop techniques that admit discontinuous payoff functions. Moreover, based on our DPP, we provide an alternative characterization of the value function as a solution of a partial differential equation in the sense of discontinuous viscosity solutions, along with boundary conditions both in Dirichlet and viscosity senses. Theoretical justifications are also discussed to pave the way for deployment of off-the-shelf PDE solvers for numerical computations. Finally, we validate the performance of the proposed framework on the stochastic Zermelo navigation problem
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