2,740 research outputs found
Relationships Among Symptoms, Brain-Derived Neurotrophic Factor (BDNF), Daily Activities, Self-Care, and Quality of Life in Breast Cancer Survivors
Background: Breast cancer survivors confront ongoing symptoms following diagnosis and treatment. Studies examining the relationship between biomarkers and symptoms are scarce. Purpose: To explore symptom occurrence and severity as reported by breast cancer survivors and their relationship to the BDNF Val66Met SNP (a biomarker), daily activities, quality of life and other selected subject characteristics and health variables. In addition, self-care methods used by survivors to alleviate symptoms and perceptions of the methods¡¯ usefulness were considered. Methods: Breast cancer survivors (6 months or more post-treatment) were invited by a coalition from a Mid-Atlantic state to participate in an online survey in Phase 1 (N = 195). The survey results provided the basis for a purposive sub-sampling. In Phase 2, two groups were identified from their scores on the Therapy-Related Symptoms Checklist (TRSC; low-scoring [¡Ü 14, n = 26] and high-scoring [¡Ý 23, n = 25]) for BDNF genotyping (by the Taqman probe assay) and exploration of self-care. All self-report tools have good psychometric properties: the TRSC, Daily Activities Rating (DAR), Health-Related Quality of Life-Linear Analogue Scale Assessment (HRQOL-LASA), and Symptom Alleviation: Self-Care Methods (SA: SCM). Fisher¡¯s exact test, logistic and multiple regression, and descriptive and content analyses were conducted. Findings: (a) The presence of the BDNF Val66Met SNP biomarker was related to lower symptom scores, but effect size was small and the relationship did not persist when controlling for confounders; (b) TRSC scores were not impacted by time since completion of treatment; (c) high total scores on the TRSC (high symptom occurrence and severity) were significantly related to high scores on the DAR (difficulty with activities of daily life) and to lower quality of life on the HRQOL-LASA; (d) the odds of a low TRSC score increased with increased education and increased age, and diminished if treatment included chemotherapy; (e) the self-care method used most commonly was diet/nutrition/lifestyle; the least common was herbs/vitamins/complementary therapy, and the methods that were used were perceived as effective. Clinical Implications and Need for Further Research: Beginning evidence that the BDNF Val66Met SNP may have a protective effect for ongoing symptoms in breast cancer survivors
A Second Host Species of the Inquiline Ant Leptothorax wilsoni
The workerless parasitic ant, Leptothorax wilsoni, as yet known only from colonies of Leptothorax cf. canadensis, was found in five colonies of a second host species, Leptothorax sp. A (sensu
Heinze and Buschinger, 1989) near Escoumins, Québec. This is the first finding of an inquiline with more than one host species in the ant tribe Formicoxenni. In contrast to a previous statemem, the palp formula of L. wilsoni is 4. 3
Evaluation of large-eddy simulations forced with mesoscale model output for a multi-week period during a measurement campaign
Large-eddy simulations (LESs) of a multi-week period during the HD(CP)2 (High-Definition Clouds and Precipitation for advancing Climate Prediction) Observational Prototype Experiment (HOPE) conducted in Germany are evaluated with respect to mean boundary layer quantities and turbulence statistics. Two LES models are used in a semi-idealized setup through forcing with mesoscale model output to account for the synoptic-scale conditions. Evaluation is performed based on the HOPE observations. The mean boundary layer characteristics like the boundary layer depth are in a principal agreement with observations. Simulating shallow-cumulus layers in agreement with the measurements poses a challenge for both LES models. Variance profiles agree satisfactorily with lidar measurements. The results depend on how the forcing data stemming from mesoscale model output are constructed. The mean boundary layer characteristics become less sensitive if the averaging domain for the forcing is large enough to filter out mesoscale fluctuations. © Author(s) 2017.BMBF/01LK1203BBMBF/01LK1203
A Variational Principle Based Study of KPP Minimal Front Speeds in Random Shears
Variational principle for Kolmogorov-Petrovsky-Piskunov (KPP) minimal front
speeds provides an efficient tool for statistical speed analysis, as well as a
fast and accurate method for speed computation. A variational principle based
analysis is carried out on the ensemble of KPP speeds through spatially
stationary random shear flows inside infinite channel domains. In the regime of
small root mean square (rms) shear amplitude, the enhancement of the ensemble
averaged KPP front speeds is proved to obey the quadratic law under certain
shear moment conditions. Similarly, in the large rms amplitude regime, the
enhancement follows the linear law. In particular, both laws hold for the
Ornstein-Uhlenbeck process in case of two dimensional channels. An asymptotic
ensemble averaged speed formula is derived in the small rms regime and is
explicit in case of the Ornstein-Uhlenbeck process of the shear. Variational
principle based computation agrees with these analytical findings, and allows
further study on the speed enhancement distributions as well as the dependence
of enhancement on the shear covariance. Direct simulations in the small rms
regime suggest quadratic speed enhancement law for non-KPP nonlinearities.Comment: 28 pages, 14 figures update: fixed typos, refined estimates in
section
Pulsating Front Speed-up and Quenching of Reaction by Fast Advection
We consider reaction-diffusion equations with combustion-type non-linearities
in two dimensions and study speed-up of their pulsating fronts by general
periodic incompressible flows with a cellular structure. We show that the
occurence of front speed-up in the sense ,
with the amplitude of the flow and the (minimal) front speed, only
depends on the geometry of the flow and not on the reaction function. In
particular, front speed-up happens for KPP reactions if and only if it does for
ignition reactions. We also show that the flows which achieve this speed-up are
precisely those which, when scaled properly, are able to quench any ignition
reaction.Comment: 16p
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