Glass transition and layering effects in confined water: a computer simulation study

Single particle dynamics of water confined in a nanopore is studied through Computer Molecular Dynamics. The pore is modeled to represent the average properties of a pore of Vycor glass. Dynamics is analyzed at different hydration levels and upon supercooling. At all hydration levels and all temperatures investigated a layering effect is observed due to the strong hydrophilicity of the substrate. The time density correlators show, already at ambient temperature, strong deviations from the Debye and the stretched exponential behavior. Both on decreasing hydration level and upon supercooling we find features that can be related to the cage effect typical of a supercooled liquid undergoing a kinetic glass transition. Nonetheless the behavior predicted by Mode Coupling Theory can be observed only by carrying out a proper shell analysis of the density correlators. Water molecules within the first two layers from the substrate are in a glassy state already at ambient temperature (bound water). The remaining subset of molecules (free water) undergoes a kinetic glass transition; the relaxation of the density correlators agree with the main predictions of the theory. From our data we can predict the temperature of structural arrest of free water.Comment: 14 pages, 15 figures inserted in the text, to be published in J. Chem. Phys. (2000

Der neue Menschenrechtsrat und das Hochkommissariat für Menschenrechte der Vereinten Nationen: Entstehung, Entwicklung und Zusammenarbeit

Maximilian Spohr beschäftigt sich mit der Entstehung, Entwicklung und Zusammenarbeit des Menschenrechtsrats und des Hochkommissariats für Menschenrechte der Vereinten Nationen. Anlässlich der Gründung des neuen Menschenrechtsrates im Jahr 2006 geht er der Frage nach, wie sich die Zusammenarbeit zwischen dem zentralen intergouvernementalen Menschenrechtsorgan der Organisation und dem Hochkommissariat verändert hat. Der Autor bewertet die Reform dabei überwiegend kritisch. So sei vor allem im Zuge der institutionellen Aufwertung des neuen Menschenrechtsrates die Unabhängigkeit des Hochkommissariats verstärkt in Frage gestellt worden. Begünstigt durch arbeitsorganisatorische Probleme am Hochkommissariat, sei es in Reaktion hierauf zu einer Abgrenzung des auf dem Mandat des Hochkommissars beruhenden Tätigkeitsbereichs gekommen. Somit sei heute insbesondere der wichtige Bereich der Vorortmissionen des Hochkommissariats kein Gegenstand der Kooperation der beiden Organe

Layer Analysis of the Structure of Water Confined in Vycor Glass

A Molecular Dynamics simulation of the microscopic structure of water confined in a silica pore is presented. A single cavity in the silica glass has been modeled as to reproduce the main features of the pores of real Vycor glass. A layer analysis of the site-site radial distribution functions evidence the presence in the pore of two subsets of water molecules with different microscopic structure. Molecules which reside in the inner layer, close to the center of the pore, have the same structure as bulk water but at a temperature of 30 K higher. On the contrary the structure of the water molecules in the outer layer, close to the substrate, is strongly influenced by the water-substrate hydrophilic interaction and sensible distortions of the H-bond network and of the orientational correlations between neighboring molecules show up. Lowering the hydration has little effect on the structure of water in the outer layer. The consequences on experimental determinations of the structural properties of water in confinement are discussed.Comment: 6 pages, 8 figures included in the text, one figure added, changes in the tex

A reminder of the road not taken: Hans-Dietrich Genscher and the holy grail of a united Europe

The state funeral of Hans-Dietrich Genscher, West Germany’s longest serving foreign minister and vice-chancellor, was held on 17 April. Kristina Spohr writes on Genscher’s career, his role in unifying Germany, and his ultimate aspiration to integrate both NATO and the Warsaw Pact into an all-European security order that incorporated the Soviet Union

Cross-lingual Entity Alignment via Joint Attribute-Preserving Embedding

Entity alignment is the task of finding entities in two knowledge bases (KBs) that represent the same real-world object. When facing KBs in different natural languages, conventional cross-lingual entity alignment methods rely on machine translation to eliminate the language barriers. These approaches often suffer from the uneven quality of translations between languages. While recent embedding-based techniques encode entities and relationships in KBs and do not need machine translation for cross-lingual entity alignment, a significant number of attributes remain largely unexplored. In this paper, we propose a joint attribute-preserving embedding model for cross-lingual entity alignment. It jointly embeds the structures of two KBs into a unified vector space and further refines it by leveraging attribute correlations in the KBs. Our experimental results on real-world datasets show that this approach significantly outperforms the state-of-the-art embedding approaches for cross-lingual entity alignment and could be complemented with methods based on machine translation

Take care! Aber bitte gegen Bezahlung

Rezension zu: Ute Gerhard, Trudie Knijn, Anja Weckwert (Hrsg.) : Erwerbstätige Mütter – Ein europäischer Vergleich ; Verlag Beck, Becksche Reihe 1514, München 2003, ISBN 3-406-49433-1, 256 Seiten, 14,90 Euro

ESTRATÉGIA INTERNACIONAL DE UMA MULTINACIONAL EMERGENTE BRASILEIRA: O CASO JBS

The focus of this study is on questioning whether the traditional theories of internationalization are adequate to explain the international expansion of multinationals from emerging countries. Looking forward on this issue, we investigate the internationalization strategies adopted by JBS, a Brazilian multinational of the beef industry. The results show that the company adopted two of the five generic strategies specific to the context of emerging countries suggested by Ramamurti and Singh (2009): global consolidator and vertical integrator. Moreover, when analyzing the internationalization of the company under study, the speed of the process is highlighted when compared to traditional multinationals. It is concluded that the main mode of entry that allowed the international expansion was the acquisition and that this strategy has advantages to the company, such as access to strategic resources and rapid growth, possibly overcoming the liability of foreignness, the opportunity to compete globally and the diversification of segments that generate synergies to the company’s activities

Modifications of the hydrogen bond network of liquid water in a cylindrical SiO_2 pore

We present results of molecular dynamics simulations of water confined in a silica pore. A cylindrical cavity is created inside a vitreous silica cell with geometry and size similar to the pores of real Vycor glass. The simulations are performed at different hydration levels. At all hydration levels water adsorbs strongly on the Vycor surface; a double layer structure is evident at higher hydrations. At almost full hydration the modifications of the confinement-induced site-site pair distribution functions are in qualitative agreement with neutron diffraction experiment. A decrease in the number of hydrogen bonds between water molecules is observed along the pore radius, due to the tendency of the molecules close to the substrate to form hydrogen-bonds with the hydrophilic pore surface. As a consequence we observe a substrate induced distortion of the H-bond tetrahedral network of water molecules in the regions close to the surface.Comment: Talk presented at "Physics of Liquids: Foundations, Highlights, Challenge", Murau Sept. 1998. To appear in J. Mol. Li

Using SPIN to formalise Accounting Regulations on the Semantic Web

Spohr D, Cimiano P, McCrae J, O'Riain S. Using SPIN to formalise Accounting Regulations on the Semantic Web. Presented at the First International Workshop on Finance and Economics on the Semantic Web in conjunction with the 9th Extended Semantic Web Conference.The eXtensible Business Reporting Language (XBRL) has standardised nancial reporting and provide a machine-interpretable for- mat that makes nancial and business reports easier to access and con- sume. Leveraging XBRL with Open Linked Data for purposes such as multi-dimensional regulatory querying and investigation requires XBRL formalisation as RDF. This paper investigates the use of o-the-shelf Se- mantic Web technologies to formalise accounting regulations specied in XBRL jurisdictional taxonomies. Specically the use of the SPARQL In- ferencing Notation (SPIN) with RDF to represent these accounting reg- ulations as rule constraints, not catered for in the RDF abstract model is investigated. We move beyond previous RDF to XBRL transformations and investigate how SPIN enhanced formalisation enables inferencing of nancial statement facts associated with nancial reporting concepts and sophisticated consistency checks, which evaluate the correctness of reported nancial data with respect to the calculation requirements im- posed by accounting regulation. The approach illustrated through two use cases demonstrates the use of SPIN to meet central requirements for nancial data and regulatory modelling