3,798 research outputs found
Distance geometry and related methods for protein structure determination from NMR data
The method of choice to reveal the conformation of protein molecules in atomic detail has been X-ray single-crystal analysis. Since the first structural analysis of diffraction patterns, computer calculations have been an important tool in these studies (Blundell & Johnson, 1976). As is described by Sheldrick (1985), it has been taken for granted that a necessary first step in the determination of a protein structure would be writing computer programs to fit structure factors. In contrast the combined use of the structural analysis of NMR data and computer calculations has been quite limited. An early attempt of such structural calculations was the quantitative determination of mononucleotide conformations in solution using lanthanide ion shifts (Barry et al. 1971
What have we learned? Assessing labor market institutions and indicators
"Over the last decade, both the availability of quantitative indicators on labor market institutions and of studies trying to explain differences in national labor market performance through institutional variables have burgeoned significantly. It is now time to review these indicators and the empirical findings. Therefore, this paper has a threefold objective: first, we provide an overview of the aggregate indicators of core labor market institutions such as employment protection, the generosity of the benefit system, active labor market policies, taxation and collective bargaining. We assess the reliability of selected indicators. Second, we review the most relevant macro-econometric studies that made use of these indicators in order to explain diverging patterns of national employment performance. Third, and finally, this paper draws some preliminary conclusions regarding the further development of aggregate indicators and possible directions for future empirical research." (Author's abstract, IAB-Doku) ((en))Arbeitsmarktpolitik, institutionelle Faktoren, Arbeitsmarktindikatoren, Kündigungsschutz, Arbeitslosenversicherung, Arbeitslosenunterstützung, Leistungshöhe, arbeitsmarktpolitische Maßnahme, Tarifverhandlungen, Steuerpolitik, Reliabilität, Arbeitsmarktforschung, empirische Forschung, Arbeitsmarktentwicklung - internationaler Vergleich, Arbeitslosenquote, OECD
A New Approach to Nuclear Collisions at RHIC Energies
We present a new parton model approach for nuclear collisions at RHIC
energies (and beyond). It is a selfconsistent treatment, using the same
formalism for calculating cross sections like the total and the inelastic one
and, on the other hand, particle production. Actually, the latter one is based
on an expression for the total cross section, expanded in terms of cut Feynman
diagrams. Dominant diagrams are assumed to be composed of parton ladders
between any pair of nucleons, with ordered virtualities from both ends of the
ladder.Comment: 8 pages, 3 figures (proceedings Quark Matter 99
On the forward-backward correlations in a two-stage scenario
It is demonstrated that in a two-stage scenario with elementary Poissonian
emitters of particles (colour strings) arbitrarily distributed in their number
and average multiplicities, the forward- backward correlations are completely
determined by the final distribution of the forward particles. The observed
linear form of the correlations then necessarily requires this distribution to
have a negative binomial form. For emitters with a negative binomial
distribution of the produced particles distributed so as to give the final
distribution also of a negative binomial form, the forward-backward
correlations have an essentially non-linear form, which disagrees with the
experimental data.Comment: 14 pages in LaTex, 1 figure in Postscrip
Quark-Gluon-Plasma Formation at SPS Energies?
By colliding ultrarelativistic ions, one achieves presently energy densities
close to the critical value, concerning the formation of a quark-gluon-plasma.
This indicates the importance of fluctuations and the necessity to go beyond
the investigation of average events. Therefore, we introduce a percolation
approach to model the final stage ( fm/c) of ion-ion collisions, the
initial stage being treated by well-established methods, based on strings and
Pomerons. The percolation approach amounts to finding high density domains, and
treating them as quark-matter droplets. In this way, we have a {\bf realistic,
microscopic, and Monte--Carlo based model which allows for the formation of
quark matter.} We find that even at SPS energies large quark-matter droplets
are formed -- at a low rate though. In other words: large quark-matter droplets
are formed due to geometrical fluctuation, but not in the average event.Comment: 7 Pages, HD-TVP-94-6 (1 uuencoded figure
Corporate Risks in Social Networks – Towards a Risk Management Framework
Social networks like Facebook or LinkedIn can be used by companies in various fields like marketing, distribution, product development or support for gaining business value. However, in contrast to these opportunities there are also corporate risks regarding the usage of social networks, for example resulting brand damages, industrial espionage or inefficiency. So far, only little understanding of corporate risks in social networks exists. Just a few single risks are discussed in literature. Thus, an extensive literature analysis was conducted for the creation of a systematic risk catalog. For a better understanding of the domain, a reference data model was developed consisting of data objects that could be exploited by attackers in social networks. Finally, a first approach towards a risk management framework is proclaimed in order to be used by companies in social networks. It integrates the identified risks, dedicated process steps and specific IT artifacts
Automated Detection of Conformational Epitopes Using Phage Display Peptide Sequences
Background: Precise determination of conformational epitopes of neutralizing antibodies represents a key step in the rational design of novel vaccines. A powerful experimental method to gain insights on the physical chemical nature of conformational epitopes is the selection of linear peptides that bind with high affinities to a monoclonal antibody of interest by phage display technology. However, the structural characterization of conformational epitopes from these mimotopes is not straightforward, and in the past the interpretation of peptide sequences from phage display experiments focused on linear sequence analysis to find a consensus sequence or common sequence motifs. Results: We present a fully automated search method, EpiSearch that predicts the possible location of conformational epitopes on the surface of an antigen. The algorithm uses peptide sequences from phage display experiments as input, and ranks all surface exposed patches according to the frequency distribution of similar residues in the peptides and in the patch. We have tested the performance of the EpiSearch algorithm for six experimental data sets of phage display experiments, the human epidermal growth factor receptor-2 (HER-2/neu), the antibody mAb Bo2C11 targeting the C 2 domain of FVIII, antibodies mAb 17b and mAb b12 of the HIV envelope protein gp120, mAb 13b5 targeting HIV-1 capsid protein and 80R of the SARS coronavirus spike protein. In all these examples th
Systemizing Colour for Conceptual Modeling
Colour is used in many conceptual models and is discussed intensively since MOODY has published his ‘Physics of Notation’. Yet, choosing the right colour for a construct is difficult but crucial. Using a colour for a certain construct which is not appropriate can lead to visual stress as well as too much or too little emphasis on that construct. The aim of this paper is to give a systematization of colour for conceptual modeling by reviewing theories of colour vision, colour harmony and visual attention. Based on this review we provide colour combinations for different conceptual modeling colour scenarios
What have we learned? Assessing labor market institutions and indicators
"Over the last decade, both the availability of quantitative indicators on labor market institutions and of studies trying to explain differences in national labor market performance through institutional variables have burgeoned significantly. It is now time to review these indicators and the empirical findings. Therefore, this paper has a threefold objective: first, we provide an overview of the aggregate indicators of core labor market institutions such as employment protection, the generosity of the benefit system, active labor market policies, taxation and collective bargaining. We assess the reliability of selected indicators. Second, we review the most relevant macro-econometric studies that made use of these indicators in order to explain diverging patterns of national employment performance. Third, and finally, this paper draws some preliminary conclusions regarding the further development of aggregate indicators and possible directions for future empirical research." (author's abstract)"In den letzten Jahren hat sowohl die Anzahl der Studien zu den gesamtwirtschaftlichen Wirkungen von Arbeitsmarktinstitutionen als auch die Zahl der vorhandenen Indikatoren zur Messung dieser Institutionen sehr stark zugenommen. Gut zehn Jahre nach Nickells (1997) maßgeblichem Beitrag über den Zusammenhang von Arbeitsmarktinstitutionen und Arbeitslosigkeit ist es an der Zeit, sowohl die Indikatoren als auch die empirischen Ergebnisse der mit ihnen erstellten Studien einer kritischen Würdigung zu unterziehen. Mit dem vorliegende Beitrag verfolgen wir drei Ziele: Erstens geben wir einen Überblick über die Indikatoren, die zur Messung der zentralen Arbeitsmarktinstitutionen - Lohnfindungssystem, Beschäftigungsschutz, Lohnersatzleistungen, Aktive Arbeitsmarktpolitik, Steuern und Abgaben - in der Literatur verwendet werden. Zweitens fassen wir die wichtigsten makroökonometrischen Studien, die diese Indikatoren verwenden, zusammen. Und schließlich diskutieren wir drittens die Ergebnisse der verschiedenen Studien, und versuchen einen Ausblick auf die (notwendige) Weiterentwicklung der Indikatoren und die zukünftige Forschung mit ihnen zu geben." (Autorenreferat
SDAP: database and computational tools for allergenic proteins
SDAP (Structural Database of Allergenic Proteins) is a web server that provides rapid, cross-referenced access to the sequences, structures and IgE epitopes of allergenic proteins. The SDAP core is a series of CGI scripts that process the user queries, interrogate the database, perform various computations related to protein allergenic determinants and prepare the output HTML pages. The database component of SDAP contains information about the allergen name, source, sequence, structure, IgE epitopes and literature references and easy links to th
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