1,832 research outputs found
Are Alcohol Excise Taxes Good For Us? Short and Long-Term Effects on Mortality Rates
Regression results from a 30-year panel of the state-level data indicate that changes in alcohol-excise taxes cause a reduction in drinking and lower all-cause mortality in the short run. But those results do not fully capture the long-term mortality effects of a permanent change in drinking levels. In particular, since moderate drinking has a protective effect against heart disease in middle age, it is possible that a reduction in per capita drinking will result in some people drinking "too little" and dying sooner than they otherwise would. To explore that possibility, we simulate the effect of a one percent reduction in drinking on all-cause mortality for the age group 35-69, using several alternative assumptions about how the reduction is distributed across this population. We find that the long-term mortality effect of a one percent reduction in drinking is essentially nil.
Implementation of exponential Rosenbrock-type methods
In this paper, we present a variable step size implementation of exponential Rosenbrock-type methods of orders 2, 3 and 4. These integrators require the evaluation of exponential and related functions of the Jacobian matrix. To this aim, the Real Leja Points Method is used. It is shown that the properties of this method combine well with the particular requirements of Rosenbrock-type integrators. We verify our implementation with some numerical experiments in MATLAB, where we solve semilinear parabolic PDEs in one and two space dimensions. We further present some numerical experiments in FORTRAN. where we compare out-method with other methods from literature. We find a great potential Of Our method for non-normal matrices. Such matrices typically arise in parabolic problems with large advection in combination with moderate diffusion and mildly stiff reactions
The processing peptidase of yeast mitochondria
Two proteins co-operate in the proteolytic cleavage of mitochondrial precursor proteins: the mitochondrial processing peptidase (MPP) and the processing enhancing protein (PEP). In order to understand the structure and function of this novel peptidase, we have isolated mutants of Saccharomyces cerevisiae which were temperature sensitive in the processing of mitochondrial precursor proteins. Here we report on the mif2 mutation which is deficient in MPP. Mitochondria from the mif2 mutant were able to import precursor proteins, but not to cleave the presequences. The MPP gene was isolated. MPP is a hydrophilic protein consisting of 482 amino acids. Notably, MPP exhibits remarkable sequence similarity to PEP. We speculate that PEP and MPP have a common origin and have evolved into two components with different but mutually complementing functions in processing of precursor proteins
Meshfree exponential integrators
For the numerical solution of time-dependent partial dierential equations, a class ofmeshfree exponential integrators is proposed. These methods are of particular interest in situationswhere the solution of the dierential equation concentrates on a small part of the computationaldomain which may vary in time. For the space discretization, radial basis functions with compactsupport are suggested. The reason for this choice are stability and robustness of the resultinginterpolation procedure. The time integration is performed with an exponential Rosenbrock method.The required matrix functions are computed by Newton interpolation based on Leja points. Theproposed integrators are fully adaptive in space and time. Numerical examples that illustrate therobustness and the good stability properties of the method are included
Aromatherapy as an Adjuvant Treatment in Cancer Care – A Descriptive Systematic Review
Claims of benefits of aromatherapy for cancer patients include reduced anxiety levels and relief of emotional stress,pain, muscular tension and fatigue. The objective of this paper is to provide an updated descriptive, systematic review of evidencefrom pre-clinical and clinical trials assessing the benefits and safety of aromatherapy for cancer patients. Literature databases suchas Medline (via Ovid), the Cochrane database of systematic reviews, Cochrane Central were searched from their inception untilOctober 2010. Only studies on cancer cells or cancer patients were included. There is no long lasting effect of aromatherapy massage, while short term improvements were reported for general well being, anxiety and depression up to 8 weeks after treatment. The reviewed studies indicate short-term effects of aromatherapy on depression, anxiety and overall wellbeing. Specifically, some clinical trials found an increase in patient-identified symptom relief, psychological wellbeing and improved sleep. Furthermore, some found a short-term improvement (up to 2 weeks after treatment) in anxiety and depression scores and better pain control. Although essential oils have generally shown minimal adverse effects, potential risks include ingesting large amounts (intentional misuse); local skin irritation, especially with prolonged skin contact; allergic contact dermatitis; and phototoxicity from reaction to sunlight (some oils). Repeated topical administration of lavender and tea tree oil was associated with reversible prepubertal gynecomastia
DIRK Schemes with High Weak Stage Order
Runge-Kutta time-stepping methods in general suffer from order reduction: the
observed order of convergence may be less than the formal order when applied to
certain stiff problems. Order reduction can be avoided by using methods with
high stage order. However, diagonally-implicit Runge-Kutta (DIRK) schemes are
limited to low stage order. In this paper we explore a weak stage order
criterion, which for initial boundary value problems also serves to avoid order
reduction, and which is compatible with a DIRK structure. We provide specific
DIRK schemes of weak stage order up to 3, and demonstrate their performance in
various examples.Comment: 10 pages, 5 figure
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