The associations of adipokines with selected markers of the renin-angiotensinogen-aldosterone system: the multi-ethnic study of atherosclerosis.

Among obese individuals, increased sympathetic nervous system (SNS) activity results in increased renin and aldosterone production, as well as renal tubular sodium reabsorption. This study determined the associations between adipokines and selected measures of the renin-angiotensinogen-aldosterone system (RAAS). The sample consisted of 1970 men and women from the Multi-Ethnic Study of Atherosclerosis who were free of clinical cardiovascular disease at baseline and had blood assayed for adiponectin, leptin, plasma renin activity (PRA) and aldosterone. The mean age was 64.7 years and 50% were female. The mean (s.d.) PRA and aldosterone were 1.45 (0.56) ng ml(-1) and 150.1 (130.5) pg ml(-1), respectively. After multivariable adjustment, a 1-s.d. increment of leptin was associated with a 0.55 ng ml(-1) higher PRA and 8.4 pg ml(-1) higher aldosterone (P<0.01 for both). Although adiponectin was not significantly associated with PRA levels, the same increment in this adipokine was associated with lower aldosterone levels (-5.5 pg ml(-1), P=0.01). Notably, the associations between aldosterone and both leptin and adiponectin were not materially changed with additional adjustment for PRA. Exclusion of those taking antihypertensive medications modestly attenuated the associations. The associations between leptin and both PRA and aldosterone were not different by gender but were significantly stronger among non-Hispanic Whites and Chinese Americans than African and Hispanic Americans (P<0.01). The findings suggest that both adiponectin and leptin may be relevant to blood pressure regulation via the RAAS, in that the associations appear to be robust to antihypertension medication use and that the associations are likely different by ethnicity

A classical particle with spin realized by reduction of a nonlinear nonholonomic constraint

In this paper we describe the motion of a nonlinear nonholonomically constrained system which after reduction realizes a nonrelativistic classical particle with spin

Planning the Future of U.S. Particle Physics (Snowmass 2013): Chapter 4: Cosmic Frontier

These reports present the results of the 2013 Community Summer Study of the APS Division of Particles and Fields ("Snowmass 2013") on the future program of particle physics in the U.S. Chapter 4, on the Cosmic Frontier, discusses the program of research relevant to cosmology and the early universe. This area includes the study of dark matter and the search for its particle nature, the study of dark energy and inflation, and cosmic probes of fundamental symmetries.Comment: 61 page

The Non-Trapping Degree of Scattering

We consider classical potential scattering. If no orbit is trapped at energy E, the Hamiltonian dynamics defines an integer-valued topological degree. This can be calculated explicitly and be used for symbolic dynamics of multi-obstacle scattering. If the potential is bounded, then in the non-trapping case the boundary of Hill's Region is empty or homeomorphic to a sphere. We consider classical potential scattering. If at energy E no orbit is trapped, the Hamiltonian dynamics defines an integer-valued topological degree deg(E) < 2. This is calculated explicitly for all potentials, and exactly the integers < 2 are shown to occur for suitable potentials. The non-trapping condition is restrictive in the sense that for a bounded potential it is shown to imply that the boundary of Hill's Region in configuration space is either empty or homeomorphic to a sphere. However, in many situations one can decompose a potential into a sum of non-trapping potentials with non-trivial degree and embed symbolic dynamics of multi-obstacle scattering. This comprises a large number of earlier results, obtained by different authors on multi-obstacle scattering.Comment: 25 pages, 1 figure Revised and enlarged version, containing more detailed proofs and remark

Non-integrability of the mixmaster universe

We comment on an analysis by Contopoulos et al. which demonstrates that the governing six-dimensional Einstein equations for the mixmaster space-time metric pass the ARS or reduced Painlev\'{e} test. We note that this is the case irrespective of the value, $I$, of the generating Hamiltonian which is a constant of motion. For $I < 0$ we find numerous closed orbits with two unstable eigenvalues strongly indicating that there cannot exist two additional first integrals apart from the Hamiltonian and thus that the system, at least for this case, is very likely not integrable. In addition, we present numerical evidence that the average Lyapunov exponent nevertheless vanishes. The model is thus a very interesting example of a Hamiltonian dynamical system, which is likely non-integrable yet passes the reduced Painlev\'{e} test.Comment: 11 pages LaTeX in J.Phys.A style (ioplppt.sty) + 6 PostScript figures compressed and uuencoded with uufiles. Revised version to appear in J Phys.

Oak forest carbon and water simulations:Model intercomparisons and evaluations against independent data

Models represent our primary method for integration of small-scale, process-level phenomena into a comprehensive description of forest-stand or ecosystem function. They also represent a key method for testing hypotheses about the response of forest ecosystems to multiple changing environmental conditions. This paper describes the evaluation of 13 stand-level models varying in their spatial, mechanistic, and temporal complexity for their ability to capture intra- and interannual components of the water and carbon cycle for an upland, oak-dominated forest of eastern Tennessee. Comparisons between model simulations and observations were conducted for hourly, daily, and annual time steps. Data for the comparisons were obtained from a wide range of methods including: eddy covariance, sapflow, chamber-based soil respiration, biometric estimates of stand-level net primary production and growth, and soil water content by time or frequency domain reflectometry. Response surfaces of carbon and water flux as a function of environmental drivers, and a variety of goodness-of-fit statistics (bias, absolute bias, and model efficiency) were used to judge model performance. A single model did not consistently perform the best at all time steps or for all variables considered. Intermodel comparisons showed good agreement for water cycle fluxes, but considerable disagreement among models for predicted carbon fluxes. The mean of all model outputs, however, was nearly always the best fit to the observations. Not surprisingly, models missing key forest components or processes, such as roots or modeled soil water content, were unable to provide accurate predictions of ecosystem responses to short-term drought phenomenon. Nevertheless, an inability to correctly capture short-term physiological processes under drought was not necessarily an indicator of poor annual water and carbon budget simulations. This is possible because droughts in the subject ecosystem were of short duration and therefore had a small cumulative impact. Models using hourly time steps and detailed mechanistic processes, and having a realistic spatial representation of the forest ecosystem provided the best predictions of observed data. Predictive ability of all models deteriorated under drought conditions, suggesting that further work is needed to evaluate and improve ecosystem model performance under unusual conditions, such as drought, that are a common focus of environmental change discussions

C-reactive protein: associations with haematological variables, cardiovascular risk factors and prevalent cardiovascular disease

C-reactive protein (CRP) has been proposed as a risk factor for cardiovascular disease; however, this association is confounded by mutual relationships with both classical and haematological cardiovascular risk factors. We, therefore, measured CRP with a high-sensitivity assay in stored plasma samples from 414 men and 515 women in the north Glasgow MONICA (MONItoring trends in CArdiovascular diseases) survey, to study its correlation with haematological variables, classical risk factors and prevalent cardiovascular disease. CRP correlated with age, oral contraceptive use, menopause and most classical cardiovascular risk factors (except blood pressure). CRP also correlated with plasma levels of the pro-inflammatory cytokine interleukin 6, and haematocrit, viscosity, red cell aggregation, white cell count, and coagulation factors [fibrinogen, factor (F) VII in women, FVIII, FIX] and inhibitors (antithrombin and protein C in women; protein S) but not coagulation activation markers. CRP was significantly associated with prevalent cardiovascular disease in both men (P = 0.03) and women (P = 0.009), however, the association became non-significant after adjustment for firstly classical risk factors, then fibrinogen. We conclude that correlations with classical and haematological risk factors account for a substantial component of the association of CRP with prevalent cardiovascular disease, but there is evidence of a residual, independent effect among women