7,693 research outputs found
Industrial Transformation and Development of Heavy Metal Emissions in Northrhine-Westfalia: Decomposition and Material Flow Analysis
This paper presents a contribution to the Regional Material Balance Approaches to Long-Term Environmental Policy Planning project (IND project). The policy part of this project - the Ruhr/Katowice Policy Comparison - aims at a better understanding of policy options for cleaning up the Black Triangle. The comparison focuses on the Ruhr Area and the Katowice voivodship which were both identified as hot spots of heavy metal pollution. The Ruhr/Katowice Policy Comparison comprises a historical analysis of the Ruhr Area, which draws heavily on the evidence collected in IIASA's previous Rhine Basin study and which investigates past policies to reduce heavy metal pollution in this area. The investigation was performed by Sander de Bruyn and Simone Schucht during their participation in IIASA's Young Scientists' Summer Program. This paper describes, both quantitatively and qualitatively, the determinants of the reduction of atmospheric heavy metal emissions in Northrhine-Westfalia. It develops methods to describe quantitatively industrial transformation and applies these methods to the analysis of industrial change in Northrhine-Westfalia during the 1955 to 1988 period
Grense vir die taalwetenskap aan die hand van 'n gegewe raamwerk
In order to study a subject with all its facets will imply, in linguistics, that contexts also have to be taken into account. In order to give a full account of language as a means of communication one also has to pay attention to the use of language. This has the result that the language (speech) act has to be studied carefully by the linguist, because it involves the correlation among speaker, auditor and utterance in language-in-usage
On the order of a non-abelian representation group of a slim dense near hexagon
We show that, if the representation group of a slim dense near hexagon
is non-abelian, then is of exponent 4 and ,
, where is the near polygon
embedding dimension of and is the dimension of the universal
representation module of . Further, if , then
is an extraspecial 2-group (Theorem 1.6)
Sustainability and indicators in Amazonia : conceptual framework for use in Amazonia
This report outlines issues of sustainable development and its measurement which can be relevant for use in the PanAmazonian Countries (PAC). It reviews concepts of sustainability that have been formulated both in the political and scientific worlds and attempts to apply them to specific issues that can be relevant for assessing sustainable development in the PAC. The report emphasises the various ways in which sustainable development can be defined and measured. It describes the evolution of the concept of sustainable development in both the political and scientific arena. Many different definitions and operationalisations of the concept of sustainable development come to the foreground. However, there does not exist a methodology that can scientifically prove which conception or operationalisation is to be preferred above the other ones. More problems arise when sustainable development is to be measured by indicators. Indicators schemes that have been provided in the literature seem to be defined ad-hoc at best. For the study area of Amazonia, the report suggests that the Agenda 21 indicators can be a useful element in future studies. The precise set of indicators to be used depends also on the sustainability patterns to be investigated (economic sectors, regions, communities), the availability and reliability of the data necessary to construct the indicators, and the questions we want to answer
A chemical ionization mass spectrometer for continuous underway shipboard analysis of dimethylsulfide in near-surface seawater
A compact, low-cost atmospheric pressure, chemical ionization mass spectrometer ("mini-CIMS") has been developed for continuous underway shipboard measurements of dimethylsulfide (DMS) in seawater. The instrument was used to analyze DMS in air equilibrated with flowing seawater across a porous Teflon membrane equilibrator. The equilibrated gas stream was diluted with air containing an isotopically-labeled internal standard. DMS is ionized at atmospheric pressure via proton transfer from water vapor, then declustered, mass filtered via quadrupole mass spectrometry, and detected with an electron multiplier. The instrument described here is based on a low-cost residual gas analyzer (Stanford Research Systems), which has been modified for use as a chemical ionization mass spectrometer. The mini-CIMS has a gas phase detection limit of 220 ppt DMS for a 1 min averaging time, which is roughly equivalent to a seawater DMS concentration of 0.1 nM DMS at 20°C. The mini-CIMS has the sensitivity, selectivity, and time response required for underway measurements of surface ocean DMS over the full range of oceanographic conditions. The simple, robust design and relatively low cost of the instrument are intended to facilitate use in process studies and surveys, with potential for long-term deployment on research vessels, ships of opportunity, and large buoys
Post-correlation radio frequency interference classification methods
We describe and compare several post-correlation radio frequency interference
classification methods. As data sizes of observations grow with new and
improved telescopes, the need for completely automated, robust methods for
radio frequency interference mitigation is pressing. We investigated several
classification methods and find that, for the data sets we used, the most
accurate among them is the SumThreshold method. This is a new method formed
from a combination of existing techniques, including a new way of thresholding.
This iterative method estimates the astronomical signal by carrying out a
surface fit in the time-frequency plane. With a theoretical accuracy of 95%
recognition and an approximately 0.1% false probability rate in simple
simulated cases, the method is in practice as good as the human eye in finding
RFI. In addition it is fast, robust, does not need a data model before it can
be executed and works in almost all configurations with its default parameters.
The method has been compared using simulated data with several other mitigation
techniques, including one based upon the singular value decomposition of the
time-frequency matrix, and has shown better results than the rest.Comment: 14 pages, 12 figures (11 in colour). The software that was used in
the article can be downloaded from http://www.astro.rug.nl/rfi-software
Quantum Monte Carlo Algorithm Based on Two-Body Density Functional Theory for Fermionic Many-Body Systems: Application to 3He
We construct a quantum Monte Carlo algorithm for interacting fermions using
the two-body density as the fundamental quantity. The central idea is mapping
the interacting fermionic system onto an auxiliary system of interacting
bosons. The correction term is approximated using correlated wave functions for
the interacting system, resulting in an effective potential that represents the
nodal surface. We calculate the properties of 3He and find good agreement with
experiment and with other theoretical work. In particular, our results for the
total energy agree well with other calculations where the same approximations
were implemented but the standard quantum Monte Carlo algorithm was usedComment: 4 pages, 3 figures, 1 tabl
HIV-discordant couples: An emerging issue in prevention and treatment
No Abstract Southern African Journal of HIV Medicine Vol. 7 (2) 2006: pp. 25-2
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