Prevention of hypertension

This review summarizes papers and reports published during the past year that contribute important knowledge or perspectives about prevention of elevated arterial blood pressure. Emphasis is on controlled intervention trials, particularly the large, multicenter Trials of Hypertension Prevention-Phase I, but all relevant randomized trials known to the author are included. Observational epidemiologic studies that are cross-sectional, eg, the INTERSALT study and the US Pitt County Study, or longitudinal, eg, the large Health Professionals Followup Study and the National Health and Nutrition Examination Survey (I) Epidemiologic Followup Study, are also discussed. The recent evidence, when viewed in the context of the previously accumulated literature, supports the recommendations of two recent expert reports to the effect that 1) much knowledge is available to help avoid the rise of blood pressure with age that is the hallmark of the epidemic of hypertension in industrialized societies, and 2) efforts should be particularly directed toward control of obesity, increased physical activity, reduced salt intake, and moderation of alcohol use.     

Relations between hormone levels and observational measures of aggressive behavior of young adolescents in family interactions.

Relations between hormone levels and aggressive behavior of adolescents in family interactions were examined in 30 boys and 30 girls, 9 to 14 years of age. The adolescents represented all five stages of pubertal development (Tanner criteria). Circulating levels of gonadotropins (luteinizing hormone and follicle-stimulating hormone), gonadal steroids (testosterone and estradiol), adrenal androgens (dehydroepiandrosterone, dehydroepiandrosterone sulphate, and androstenedione), and testosterone-estradiol binding globulin were assessed. These hormones are responsible for growth and sexual development during puberty and correlate with Tanner stage. The behavioral measures described the adolescents' expressions of anger and attempts to control or defy their parents and were based on videotaped family interactions during problem-solving tasks. On the basis of multiple regression analyses, higher estradiol and androstenedione levels were associated with higher degrees of aggressive behaviors for girls. Findings were sparse for boys. Findings are discussed in terms of (a) effects of degree of stability of hormone levels on detection of hormone-behavior relations, (b) organizing and activating influences of hormones on behavior, and (c) other mechanisms possibly underlying the relations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Processing of Dense ζ‐Ta4C3−x by Reaction Sintering of Ta and TaC Powder Mixture

Tantalum carbides are commonly processed by hot pressing, canned hot‐isostatic‐pressing, or spark plasma sintering because of their high melting temperatures and low diffusivities. This paper reports processing of dense ζ‐Ta₄C_3?x by reaction sintering of a Ta and TaC powder mixture (C/Ta atomic ratio = 0.66). ζ‐Ta₄C_3?x is of interest due to its rhombohedral (trigonal) crystal structure that may be characterized as a polytype with both face‐centered‐cubic and hexagonal‐close‐packed Ta stacking sequences interrupted by stacking faults and missing carbon layers. This structure leads to easy cleaving on the basal planes and high fracture toughness. A key step in processing is the hydrogenation of the Ta powder to produce β‐TaH_x, a hard and brittle phase that enables efficient comminution during milling and production of small, equiaxed Ta particles that can be packed to high green density with the TaC powder. Studies of phase evolution by quantitative X‐ray diffraction during sintering revealed several intermediate reactions: (1) decomposition of β‐TaH_x to Ta; (2) diffusion of C from γ‐TaC to Ta leading to the formation of α‐Ta₂C_y' with the kinetics described by the Avrami equation with an exponent, n = 0.5, and an activation energy of 219 kJ/mole; (3) equilibration of α‐Ta₂C_y' and γ‐TaC_0.78 phases; and (4) formation of ζ‐Ta₄C_2.56 from the equilibrated α‐Ta₂C and γ‐TaC_0.78 phases with the kinetics characterized by a higher Avrami exponent (n ≈ 3) and higher activation energy (1007 kJ/mole). The sintered material contained ~0.86 weight fraction ζ‐Ta₄C_2.56 and ~0.14 weight fraction γ‐TaC_0.78 phases. The microstructure showed evidence of nucleation and growth of the ζ‐Ta₄C_2.56 phase in both the α‐Ta₂C and γ‐TaC_0.78 parent phases with distinct difference in the morphology due to the different number of variants of the habit plane.     

Detecting,categorizing and forecasting large ramps in wind farm power output using meteorological observations and WPPT

The Wind Power Prediction Tool (WPPT) has been installed in Australia for the first time, to forecast the power output from the 65MW Roaring 40s Renewable Energy P/L Woolnorth Bluff Point wind farm. This article analyses the general performance of WPPT as well as its performance during large ramps (swings) in power output. In addition to this, detected large ramps are studied in detail and categorized. WPPT combines wind speed and direction forecasts from the Australian Bureau of Meteorology regional numerical weather prediction model, MesoLAPS, with real‐time wind power observations to make hourly forecasts of the wind farm power output. The general performances of MesoLAPS and WPPT are evaluated over 1 year using the root mean square error (RMSE). The errors are significantly lower than for basic benchmark forecasts but higher than for many other WPPT installations, where the site conditions are not as complicated as Woolnorth Bluff Point. Large ramps are considered critical events for a wind power forecast for energy trading as well as managing power system security. A methodology is developed to detect large ramp events in the wind farm power data. Forty‐one large ramp events are detected over 1 year and these are categorized according to their predictability by MesoLAPS, the mechanical behaviour of the wind turbine, the power change observed on the grid and the source weather event. During these events, MesoLAPS and WPPT are found to give an RMSE only roughly equivalent to just predicting the mean (climatology forecast). Copyright © 2007 John Wiley & Sons, Ltd.     

Global Illumination Compensation for Spatially Augmented Reality

When projectors are used to display images on complex, non‐planar surface geometry, indirect illumination between the surfaces will disrupt the final appearance of this imagery, generally increasing brightness, decreasing contrast, and washing out colors. In this paper we predict through global illumination simulation this unintentional indirect component and solve for the optimal compensated projection imagery that will minimize the difference between the desired imagery and the actual total illumination in the resulting physical scene. Our method makes use of quadratic programming to minimize this error within the constraints of the physical system, namely, that negative light is physically impossible. We demonstrate our compensation optimization in both computer simulation and physical validation within a table‐top spatially augmented reality system. We present an application of these results for visualization of interior architectural illumination. To facilitate interactive modifications to the scene geometry and desired appearance, our system is accelerated with a CUDA implementation of the QP optimization method.