Relationship between cortisol and physical performance in older persons

Objective: Hypercortisolism is associated with muscle weakness. This study examines the relationship between cortisol and physical performance in older persons. Design/patients: The study was conducted within the Longitudinal Aging Study Amsterdam (LASA), an ongoing cohort study in a population-based sample of healthy older persons in the Netherlands. Data from the second (1995/1996) and fourth (2001/2002) cycle were used pertaining to 1172 (65-88 years) and 884 (65-94 years) men and women, respectively. Measurements: Physical performance was measured by adding up scores on the chair stands, tandem stand and walk test (range 0-12). In the second cycle serum total and calculated free cortisol were assessed; in the fourth cycle evening salivary cortisol was assessed. Regression analysis (stratified for sex, adjusted for age, body mass index, alcohol use, physical activity and region) was performed to examine the cross-sectional relationship between cortisol and physical performance. Results: Women with higher calculated free cortisol scored less well on physical performance (b = -0.28 per SD higher cortisol, P = 0.016), which was mainly explained by poorer performance on the tandem stand (OR = 1.32 for a lower score per SD higher cortisol, P = 0.003). Men with higher salivary cortisol scored less well on physical performance (b = -0.90 in the highest vs. the lowest quartile, P = 0.008), which was mainly explained by poorer performance on the chair stands and walk test (OR = 1.88, P = 0.020 and OR = 1.81, P = 0.027, respectively, in the highest vs. the lowest quartile). Conclusion: Physical performance is negatively associated with high cortisol levels in older persons. © 2007 The Authors

Digital History: Towards New Methodologies

The field of Digital Humanities is changing the way historians do their research. Historians use tools to query larger data sets and they apply a different methodology to tackle certain research questions. In this paper we will discuss two propositions on the necessity of adapting to and taking advantage of the technological changes: (1) Digital Humanities tools are not the enemy of the historian, but they need to be used in a proper way. This requires historians to make ‘tool criticism’ part of their methodological toolkit; (2) Digital Humanities tools allow for a more data-driven and bottom-up approach to historical research. This eliminates some of the historian’s preconceptions that are inevitably part of more traditional historical research

Prolonged oral treatment with MK-677, a novel growth hormone secretagogue, improves sleep quality in man

info:eu-repo/semantics/publishe

Effects of 7-day treatment with the orally active growth hormone (GH) secretagogue, MK-677, on insulin-like growth factor-I (IGF-I) levels, 24-hour GH and cortisol profiles, and sleep in normal young men

abstractinfo:eu-repo/semantics/nonPublishe

Efficient introduction of alkene functionality into proteins in vivo

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The evolution of gas-phase metallicity and resolved abundances in star-forming galaxies at z ≍ 0.6-1.8

We present an analysis of the chemical abundance properties of ≈650 star-forming galaxies at z ≈ 0.6–1.8. Using integral-field observations from the K-band multi-object spectrograph (KMOS), we quantify the [N II]/H α emission-line ratio, a proxy for the gas-phase oxygen abundance within the interstellar medium. We define the stellar mass–metallicity relation at z ≈ 0.6–1.0 and z ≈ 1.2–1.8 and analyse the correlation between the scatter in the relation and fundamental galaxy properties (e.g. H α star formation rate, H α specific star formation rate, rotation dominance, stellar continuum half-light radius, and Hubble-type morphology). We find that for a given stellar mass, more highly star-forming, larger, and irregular galaxies have lower gas-phase metallicities, which may be attributable to their lower surface mass densities and the higher gas fractions of irregular systems. We measure the radial dependence of gas-phase metallicity in the galaxies, establishing a median, beam smearing corrected, metallicity gradient of ΔZ/ΔR = 0.002 ± 0.004 dex kpc−1, indicating on average there is no significant dependence on radius. The metallicity gradient of a galaxy is independent of its rest-frame optical morphology, whilst correlating with its stellar mass and specific star formation rate, in agreement with an inside–out model of galaxy evolution, as well as its rotation dominance. We quantify the evolution of metallicity gradients, comparing the distribution of ΔZ/ΔR in our sample with numerical simulations and observations at z ≈ 0–3. Galaxies in our sample exhibit flatter metallicity gradients than local star-forming galaxies, in agreement with numerical models in which stellar feedback plays a crucial role redistributing metals

Fuzzy Dominance Based Multi-objective GA-Simplex Hybrid Algorithms Applied to Gene Network Models

Abstract. Hybrid algorithms that combine genetic algorithms with the Nelder-Mead simplex algorithm have been effective in solving certain optimization problems. In this article, we apply a similar technique to estimate the parameters of a gene regulatory network for flowering time control in rice. The algorithm minimizes the difference between the model behavior and real world data. Because of the nature of the data, a multi-objective approach is necessary. The concept of fuzzy dominance is introduced, and a multi-objective simplex algorithm based on this concept is proposed as a part of the hybrid approach. Results suggest that the proposed method performs well in estimating the model parameters. 1 Gene Regulatory Network Models Molecular geneticists are rapidly deciphering the genomes of an increasing number of organisms. As of November 2003, 166 organisms had completely sequenced genomes with another 775 in progress [1]. The current challenge is to understand how the genes in each organism interact with each other and the environment t