22 research outputs found
Homocysteine and Coronary Heart Disease: Meta-analysis of MTHFR Case-Control Studies, Avoiding Publication Bias
Robert Clarke and colleagues conduct a meta-analysis of unpublished datasets to examine the causal relationship between elevation of homocysteine levels in the blood and the risk of coronary heart disease. Their data suggest that an increase in homocysteine levels is not likely to result in an increase in risk of coronary heart disease
Modeling of the plastic characteristics of AA6082 for the friction stir welding process
Focus of this paper is to model the plastic forming behavior of AA6082, in order to
develop the numerical FE analysis of the friction stir welding processes and the simulation of
subsequent forming processes. During the friction stir welding process, the temperatures reached
can range up to 500 \ub0C and have a fundamental role for the correct performance of the process, so
the material data has to show a temperature dependency. Because of the tool rotation a strain rate
sensitivity of the material has to be respected as well. In this context, the general material
characteristics of AA6082 were first identified for different stress states. For the uniaxial state the
standard PuD-Al used in the automotive industry was applied, for the shear state the ASTM B831-
05 was used and for biaxial states the ISO 16842 was exploited. To characterize the plastic flow
behavior of the AA6082 at elevated temperatures, tensile tests were performed according to DIN
EN ISO 6892-2 from 25 \ub0C to 500 \ub0C with a strain rate from 0.1 s-1 up to 6.5 s-1
Climate variability and change in the Greater Alpine Region over the last two centuries based on multi-variable analysis
An extensive analysis of the HISTALP database is presented with the aim of giving a comprehensive picture of secular climate variability and change in the Greater Alpine Region (GAR, 4-19 E, 43-49 N). The HISTALP database encompasses 242 sites and concerns temperature, pressure, precipitation, Cloudiness, Sunshine duration, vapour pressure and relative humidity. The analyses are based on four regional mean records representing different GAR low-level areas and on an additional mean record representing high-level locations.
The first goal of the paper is to give an overview of the seasonal and annual records for the different variables, aiming to highlight both variability on decadal time scale and long-term evolution. Then it focuses on trend and correlation analysis. Trends are presented both for the period of common data availability for all regional average series and for moving windows that permit studying the trends over a wide range of timescales. Correlations among the different variables are presented both for the regional average series and for their high-pass-filtered versions.
The analyses, beside highlighting a warming that is about twice as large its the global trend. also show that the different variables have responded in different ways to this warming and that the mutual interactions linking the different variables are often present only at specific temporal scales and only in parts of the GAR and in defined seasons. In spite of this complex behaviour, which may also be due to some residual inhomogeneities still affecting the data, the analyses give evidence that the HISTALP database has in excellent internal consistency and show that the availability of a multi-variable database turns out to be very useful in order to evaluate the reliability of the reconstruction of each variable and to better understand the behaviour and the mutual interactions of the different variables
Multi-variable analysis of 200 years of climate variability and change in the Greater Alpine Region
HISTALP, a large multi-variable dataset consisting of monthly quality-checked and homogenised secular records for
the \u201cGreater Alpine Region\u201d (GAR, 4-19 \ub0E, 43-49 \ub0N, 0-3500m asl), has been set up in the last 10 years within the
frame of a number of projects coordinated by the Austrian Meteorological Central Office. It encompasses 242 sites and
concerns temperature, pressure, precipitation, sunshine, cloudiness, vapour pressure and relative humidity. The climate
information in HISTALP is not only stored in station-mode, but also by means of gridded data and Coarse Resolution
Subregional Mean series (CRSMs), that are available at monthly, seasonal and yearly resolution.
In this context, we are analysing the HISTALP database with the aim at giving a comprehensive picture of secular
climate variability and change in the GAR, by means of the analysis of a wide range of relevant meteorological
variables (temperature, precipitation, pressure, cloudiness, sunshine duration, vapour pressure and relative humidity).
This extended abstract shows some preliminary results of our research; full details will be given in a comprehensive
paper that is currently in preparation
Patterns of precipitation variability in the Greater Alpine Region
A recently set up and homogenised new precipitation dataset for the Greater Alpine Region (GAR) is
presented here with some first preliminary analyses. Climate change patterns within the study region are analysed in
terms of regionally different evolutions, seasonality, and short to long-term trends. It will be shown that precipitation
presents pronouncedly different variability patterns in space as well as in terms of seasonality and at different time
scales