57 research outputs found
DOMAIN WALLS IN MAGNETO-ELASTIC HETEROSTRUCTURES:MODELING AND EXPERIMENT
International audienc
The Open Global Glacier Model (OGGM) v1.1
Despite their importance for sea-level rise, seasonal water availability, and
as a source of geohazards, mountain glaciers are one of the few remaining
subsystems of the global climate system for which no globally applicable,
open source, community-driven model exists. Here we present the Open Global
Glacier Model (OGGM), developed to provide a modular and open-source
numerical model framework for simulating past and future change of any
glacier in the world. The modeling chain comprises data downloading tools
(glacier outlines, topography, climate, validation data), a preprocessing
module, a mass-balance model, a distributed ice thickness estimation model,
and an ice-flow model. The monthly mass balance is obtained from gridded
climate data and a temperature index melt model. To our knowledge, OGGM is
the first global model to explicitly simulate glacier dynamics: the model
relies on the shallow-ice approximation to compute the depth-integrated flux
of ice along multiple connected flow lines. In this paper, we describe and
illustrate each processing step by applying the model to a selection of
glaciers before running global simulations under idealized climate forcings.
Even without an in-depth calibration, the model shows very realistic
behavior. We are able to reproduce earlier estimates of global glacier volume
by varying the ice dynamical parameters within a range of plausible values.
At the same time, the increased complexity of OGGM compared to other
prevalent global glacier models comes at a reasonable computational cost:
several dozen glaciers can be simulated on a personal computer, whereas
global simulations realized in a supercomputing environment take up to a few
hours per century. Thanks to the modular framework, modules of various
complexity can be added to the code base, which allows for new kinds of model
intercomparison studies in a controlled environment. Future developments will
add new physical processes to the model as well as automated calibration
tools. Extensions or alternative parameterizations can be easily added by the
community thanks to comprehensive documentation. OGGM spans a wide range of
applications, from ice–climate interaction studies at millennial timescales
to estimates of the contribution of glaciers to past and future sea-level
change. It has the potential to become a self-sustained community-driven
model for global and regional glacier evolution.</p
Obesity prevalence from a European perspective: a systematic review
<p>Abstract</p> <p>Background</p> <p>Obesity has been recognised as an important contributing factor in the development of various diseases, but comparative data on this condition are limited. We therefore aimed to identify and discuss current epidemiological data on the prevalence of obesity in European countries.</p> <p>Methods</p> <p>We identified relevant published studies by means of a MEDLINE search (1990–2008) supplemented by information obtained from regulatory agencies. We only included surveys that used direct measures of weight and height and were representative of each country's overall population.</p> <p>Results</p> <p>In Europe, the prevalence of obesity (body mass index ≥ 30 kg/m<sup>2</sup>) in men ranged from 4.0% to 28.3% and in women from 6.2% to 36.5%. We observed considerable geographic variation, with prevalence rates in Central, Eastern, and Southern Europe being higher than those in Western and Northern Europe.</p> <p>Conclusion</p> <p>In Europe, obesity has reached epidemic proportions. The data presented in our review emphasise the need for effective therapeutic and preventive strategies.</p
Expression of the Corynebacterium glutamicum panD gene encoding L-aspartate-alpha-decarboxylase leads to pantothenate overproduction in Escherichia coli
Dusch N, Pühler A, Kalinowski J. Expression of the Corynebacterium glutamicum panD gene encoding L-aspartate-alpha-decarboxylase leads to pantothenate overproduction in Escherichia coli. Appl Environ Microbiol. 1999;65(4):1530-1539.The Corynebacterium glutamicum panD gene was identified by functional complementation of an Escherichia coli panD mutant strain. Sequence analysis revealed that the coding region of panD comprises 411 bp and specifies a protein of 136 amino acid residues with a deduced molecular mass of 14.1 kDa. A defined C. glutamicum panD mutant completely lacked L-aspartate-alpha-decarboxylase activity and exhibited beta-alanine auxotrophy, The C. glutamicum panD (panD(C.g.)) as well as the E. coli panD (panD(E.c.)) genes were cloned into a bifunctional expression plasmid to allow gene analysis in C. glutamicum as well as in E. coli. The enhanced expression of panD(C.g.) in C. glutamicum resulted in the formation of two distinct proteins In sodium dodecyl sulfate-polyacrylamide gel electrophoresis, leading to the assumption that the panD(C.g.) gene product is proteolytically processed into two subunits, By increased expression of panD(C.g.) in C. glutamicum, the activity of L-aspartate-alpha-decarboxylase was 288-fold increased, whereas the panD(E.c.) gene resulted only in a 4-fold enhancement. The similar experiment performed in E. coli revealed that panD(C.g.) achieved a 41-fold increase and that panD(E.c.) achieved a 3-fold increase of enzyme activity. The effect of the panD(C.g.) and panD(E.c.) gene expression in E, coli was studied with a view to pantothenate accumulation. Only by expression of the panD(C.g.) gene was sufficient p-alanine produced to abolish its limiting effect on pantothenate production. In cultures expressing the panD(E.c.) gene, the maximal pantothenate production was still dependent on external beta-alanine supplementation. The enhanced expression of panD(C.g.) in E. coli yielded the highest amount of pantothenate in the culture medium, with a specific productivity of 140 ng of pantothenate mg (dry weight)(-1) h(-1)
Developing a Framework for Mapping Sustainable Design Activities
The notion of sustainable design has become increasingly prominent within the design community. As a result, numerous design theories, strategies and tools are available to designers. Yet, limited attempts in the field evaluate these activities by placing them in relation to each other or within the broader context of sustainable development. Based on a literature review this study develops an integrated framework which connects the areas of sustainable development and sustainable design. This framework may be utilised in two ways: firstly, to visualise the interdependencies of sustainable design and sustainable development; secondly, as an assessment tool to measure and compare the potential of sustainable design activities
Revisiting Sustainable Design Strategies
Over the past two decades a number of major eco- and sustainable design strategy compilations have been introduced (Brezet and Hemel, 1997; Thompson, 1999; Fuad-Luke, 2009). The immediate aim of these compilations is to provide an overview of the available strategies (such as ‘Recycling’ or ‘Dematerialisation’) in a structured format. However, on a more fundamental level, they all intend to contribute to a better integration of theoretical concepts on one side and applied design activities on the other. Yet, due to the sheer variety of different approaches in naming and clustering the design strategies, there is a considerable degree of ambiguity in the literature. This ultimately contradicts the aim of providing the structure and clarity required for effective planning and communication between stakeholder
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