An Accept-and-Reject Algorithm to Sample from a Set of Permutations Restricted by a Time Constraint

A modification of an accept-and-reject algorithm to sample from a set of restricted permutations is proposed. By concentrating on a special class of matrices obtained by restriction of the permutation in time, assuming the objects to be permuted to be events in time, the modified algorithm's running time can be shown to be linear instead of geometric in the number of elements. The implementation of the algorithm in the language R is presented in a Literate Programming style.

The impact of regionalised RTDI policy measures in Germany: the Network RNA Technologies Berlin (RiNA) as an example

Taking the most popular regional RTDI policy concepts, particularly the network para-digm (Cooke/Morgan 1993) as a starting point, it is the objective of this paper to theo-retically and empirically discuss the necessity and impact of regional or regionalised RTDI policy measures within the context of multi-level governance. Based on the pro-motional measure Netzwerk RNA-Technologien Berlin, initiated by the German Minis-try of Education and Research (BMBF), we shall discuss what kinds of specific policy measures can be undertaken in order to activate and support regionally embedded scientific-technological potentials. In addition, attention will be paid to challenges re-garding the multi-level governance of the funding measure and regional and national effects, particularly within the context of research and networks aspects. What can be seen from the case study is that the coordination of the funding measure proved to be quite challenging. Due to the long-lasting andcomplicated process of setting up the funding measure and the implicit, diverging goals and interests of the key players BMBF, Senate and industry, the resulting network is characterised by unique structural elements which are intertwined or overlap with each other in complex ways. However, due to the policy measure - which supports network activities primarily within coopera-tion projects -, the cooperation intensity of scientific institutions with companies was increased significantly, thus contributing to the goal of fostering the commercial exploitation of research results. --

Humor en el juego de los reyes: la Torre de la mirada sesgada de la piezas de ajedrez de Lewis

The cultural turn of the twentieth century’s last quarter gradually led to a new approach to the classical objects of historical research. Historians nowadays are required to take on a 'cultural perspective' in the course of their studies. Using the example of a particular piece of the Lewis Chessmen this paper examines both the benefits and the limitations that come about with the cultural approach and cautions against a too rigid application.A Virada Cultural do ultimo quarto do século XX levou, gradualmente, a novas abordagens dos objetos de pesquisa clássicos. Atualmente, historiadores precisam levar em consideração uma "perspectiva cultural" no decorrer de seus estudos. Usando como exemplo uma peça específica do xadrez de Lewis, este artigo examinará tanto os benefícios como as limitações que advém da abordagem cultural, bem como as cautelas tomadas contra uma aplicação muito rígida

Humour in the Game of Kings: The Sideways Glancing Warder of the Lewis Chessmen

The cultural turn of the twentieth century's last quarter gradually led to a new approach to the classical objects of historical research. Historians nowadays are required to take on a 'cultural perspective' in the course of their studies. Using the example of a particular piece of the Lewis Chessmen this paper examines both the benefits and the limitations that come about with the cultural approach and cautions against a too rigid application.A Virada Cultural do ultimo quarto do século XX levou, gradualmente, a novas abordagens dos objetos de pesquisa clássicos. Atualmente, historiadores precisam levar em consideração uma "perspectiva cultural" no decorrer de seus estudos. Usando como exemplo uma peça específica do xadrez de Lewis, este artigo examinará tanto os benefícios como as limitações que advém da abordagem cultural, bem como as cautelas tomadas contra uma aplicação muito rígida

Rückblick, Einblick, Ausblick – und stets die Umwelt im Blick : 14 Jahre Grüne Schule am Botanischen Garten der Universität Osnabrück

Bereits 1993 wurde am Botanischen Garten der Universität Osnabrück eine Grüne Schule gegründet. Viele Vorüberlegungen, wegbereitende Maßnahmen und persönliches Engagement waren der Gründung vorausgegangen. Die Grüne Schule Osnabrück entwickelte sich schnell und verfügt heute über ein pädagogisches Programm für Schulen aller Schulformen und Klassenstufen sowie Kindergärten. Darüber hinaus können interessierte Erwachsenengruppen in allgemeinen Gartenführungen oder speziellen Themenführungen die Vielfalt des Botanischen Gartens erleben. Im Freizeitbereich engagiert sich die Grüne Schule bei Kindergeburtstagen, Ferienpassaktionen oder kulturellen Veranstaltungen des Botanischen Gartens sowie bei Aktivitäten des Verbandes Botanischer Gärten e.V. Grundlegender Anspruch ist es, wissenschaftliche Themen für die Öffentlichkeit didaktisch aufzubereiten, um biologische Zusammenhänge möglichst lebendig zu vermitteln.A „Green School” exists at the Botanical Garden of Osnabrück University since 1993. Before its foundation there have been well-considered plannings and much personal engagement. The “Green School” developed quickly and today there are education programmes for all kinds of schools, starting from elementary school up to grammar school and vocational school. Adult visitors can have a look at the diversity of the Botanical Garden by guided tours or by special activity programmes. Furthermore the “Green School” offers birthday parties and holiday courses to children. Cultural events of the Botanical Garden and the Association of Botanical Gardens are supported. The aim is to process science for public, to educate people and to interest visitors in nature and environment

Cultivation and analysis of anthocyanin containing types of potatoes in organic farming regarding cultivability and additional health benefits

In a two year research project a representative spectrum of blue potato varieties were cultivated and tested in detail regarding disease infestation, yield potential and the influence of production systems (organic). Cultivation recommendations for blue potatoes could be deduced from this. Furthermore the varying anthocyanin content as well as the antioxidant capacity of the varieties used was analysed. Varieties with a particularly high content will undergo further tests to show the influence of the manner of preparation (boiling, steaming, frying) and determine their use for the processing industry. The combination of ecologically produced potatoes with „additional health benefits“ arouses the customers interest. The cultivation of high yield blue types can be an alternative to the cultivation of yellow fleshed high yield varieties in organic operating companies

Mezopórusos hibrid anyagok új típusú előállítása = New preparation of mesoporous hybrid materials

Az alumínium-szilikát gélrendszerekkel végzett kísérletek célja a szol-gél módszerrel előállított gélminták törékenységének csökkentése volt az elért nagymértékű Al-beépülés megőrzése mellett. Polimerek adagolásával 4-5-szörös mechanikai szilárdságnövelést lehetett elérni, a hibridrendszerek vizes közegű mosása pedig 8-szorosra növelte a szilárdságot a fraktál szerkezetű alumínium-szilikát gélek szárított mintáihoz hasonlítva. A tenzidek alkalmazása az alumínium-szilikát géleknél szilárdság csökkenést okozott a fraktál szerkezet megbontása, széttöredezése miatt. Legnagyobb szilárdságnövelő hatást az alumínium-, ill. szilicium-prekurzorok szilárdság szempontjából optimális kiválasztásával értük el. A környezetvédelmi szempontoknak is jól megfelelő Al-acetát és az olcsó vízüveg adta egy új alumínium-szilikát előállítás alapanyagait. A vízüvegből és Al-acetátból nyert gélminta nagy szilárdsága egy nanokompozit szerkezetnek köszönhető, nanoméretű alumíniumtartalmú kristályos részecskék ágyazódnak be egy amorf alumínium-szilikát, háromdimenziós térhálóba. Ezt a kiváló mechanikai paramétert csak egy meghatározott Al/Si mólarány felett (? 2) lehetett elérni. A nagyobb szilárdságú anyagok jellemzésére szolgáló Vickers mérővel 100-300 HV értékek adódtak a megnövelt szilárdságú minták mérésekor, az összehasonlításul szolgáló fraktál szerkezetű, szárított alumínium-szilikát minták HV értéke 0 volt. | The aim of this work was to decrease the fragility of the gel samples prepared by sol-gel method and to retain the high Al incorporation into the silica network. The strength of the dried gel samples increases about four- or fivefold by the addition of polymers to the aluminosilicate component. A washing step improves the strength of these hybrid systems by seven- or eightfold. The tenside treatments gel samples decreased the mechanical strength, reduced the porosity by 30-80 % owing to the distortion of fractal structure. The largest increase of mechanical strength can be obtained by change of Al and Si precursors. Replacing the TEOS by cheap water glass solution (sodium metasilicate) and adding to the Al acetate aqueous solution, a hard, compact composite system developed in basic medium. Al-containing, crystalline nanoparticles are inserted in amorphous aluminosilicate network. The excellent hardness can be achieved only at or above 2 mole ratio of Al/Si. Vickers test detected the best values for mechanical property in the gel derived samples prepared from aluminum acetate and water glass solution (100-300 HV), the Vickers value of other gel derived aluminosilicate samples was 0