Toward a More Comprehensive Operational Definition of Student and Faculty Member Informal Contact

Graduate students identified as high interactors and faculty members teaching graduate level courses participated in a questionnaire and interview study designed to expand on the existing operational definitions of student-faculty informal contact as a research variable. Statistically significant differences were found between student and faculty subjects on items concerning who defined the relationships, accessibility, and advisement. Student and faculty subjects were in agreement on a range of items concerning initiation of contact, degree of impact, context of interaction, and amount of informality. A discussion of the matter of selection, generalizability of the findings, and institutional factors is presented. Finally, recommendations are made concerning the practical implications of this area of study

Assessment of atomic charge models for gas-phase computations on polypeptides

The concept of the atomic charge is extensively used to model the electrostatic properties of proteins. Atomic charges are not only the basis for the electrostatic energy term in biomolecular force fields but are also derived from quantum mechanical computations on protein fragments to get more insight into their electronic structure. Unfortunately there are many atomic charge schemes which lead to significantly different results, and it is not trivial to determine which scheme is most suitable for biomolecular studies. Therefore, we present an extensive methodological benchmark using a selection of atomic charge schemes [Mulliken, natural, restrained electrostatic potential, Hirshfeld-I, electronegativity equalization method (EEM), and split-charge equilibration (SQE)] applied to two sets of penta-alanine conformers. Our analysis clearly shows that Hirshfeld-I charges offer the best compromise between transferability (robustness with respect to conformational changes) and the ability to reproduce electrostatic properties of the penta-alanine. The benchmark also considers two charge equilibration models (EEM and SQE), which both clearly fail to describe the locally charged moieties in the zwitterionic form of penta-alanine. This issue is analyzed in detail because charge equilibration models are computationally much more attractive than the Hirshfeld-I scheme. Based on the latter analysis, a straightforward extension of the SQE model is proposed, SQE+Q0, that is suitable to describe biological systems bearing many locally charged functional groups

The evolution of barriers to exploitation: Sometimes the Red Queen can take a break.

We propose a general barrier theory as an evolutionary framework for understanding coevolutionary effects of conflicts of interest in natural and human systems. It is generalized from the barrier theory of cancer, which describes how cancer develops through the evasion of mechanisms, that block unregulated cellular reproduction and survival. Barriers are naturally evolved or artificially implemented mechanisms for blocking exploitation; restraints are mechanisms that impede but do not block exploitation. When conflicts of interest arise, selection will favor exploiters that are capable of overcoming barriers and restraints. When barriers are in place, they halt, at least temporarily, coevolutionary arms races (the Red Queen can stop running). Barriers occur in a broad spectrum of interactions characterized by conflicts of interest: barriers to cellular survival (apoptosis) and reproduction (cell cycle arrest) may block a virus from replicating its genome through reproduction of its host cell. Vaccines may completely protect against targeted pathogens. A plant may escape herbivory by evolving defensive chemicals that block herbivory. Obligate mutualisms may evolve when barriers to horizontal transmission favor symbionts that increasingly lose mechanisms that contribute to horizontal transmission. Here, we show how the barrier theory applies across a spectrum of natural and social systems

Investigation of the light-induced copper-catalyzed allylic alkynylation: exploration of conditions, substrates and reaction mechanism

This dissertation reports the investigation of the light-induced copper-catalyzed allylic alkynylation. Through further optimization, a reliable and robust protocol was established. In addition, the improved protocol was subjected to various substrates with varied success. Mechanistic studies were accompanied by spectroscopic inves-tigations with NMR, EPR and CV. Together with insights gathered from the perturbation of reaction conditions a new mechanistic proposal could be presented.Die vorliegende Dissertation befasst sich mit der Untersuchung der licht-induzierten kupfer-katalysierten allylischen Alkynylierung. Durch weitergehende Optimierungen wurde ein verlässliches und robustes Protokoll etabliert. Zusätzlich konnten weitere Substrate mit unterschiedlichem Erfolg mit dieser Methode untersucht werden. Mechanistische Studien werden durch spektroskopische Untersuchungen mittels NMR, EPR und CV begleitet. Zusammen mit den Erkenntnissen aus vorhergehenden Störungsversuchen wird ein neuer mechanistischer Vorschlag präsentiert

Velocidad, guerra y video: Paul Virilio entrevistado por François Ewald

¿Podría ser urbanista Paul Virilio? Probablemente, pero no es sólo urbanista. ¿Arquitecto? No, es más todavía: un filósofo que consagra su tiempo a leer el presente, pero no tanto en lo dicho o escrito sino en lo que se inscribe en el espacio. Paul Virilio pertenece a otra especie: la filosofía de la técnica. Su amigo Claude Parent dijo de él: «Es el arqueólogo del futuro». Lo cierto es que Paul Virilio siempre procura captar las virtualidades de las técnicas que atraviesan nuestros cuerpos y organizan nuestras relaciones con el mundo y con los demás . Su último libro, La velocidad de liberación (Ed. Galilée), propone una descripción sorprendente de un mundo de ahora en adelante ligado a las técnicas de las telecomunicaciones: el tiempo anula el espacio. Paul Virilio describe allí el peligro especifico en el accidente en general. E invita a la formación de una ecología gri

Mitschrift der Vorlesung zu Atomlehre [von Paul Peter Ewald durch H. Hertlein] im Wintersemester 1925/26

MITSCHRIFT DER VORLESUNG ZU ATOMLEHRE [VON PAUL PETER EWALD DURCH H. HERTLEIN] IM WINTERSEMESTER 1925/26 Mitschriften und Skripte von Vorlesungen an der Technischen Hochschule und Universität Stuttgart (-) Mitschrift der Vorlesung zu Atomlehre [von Paul Peter Ewald durch H. Hertlein] im Wintersemester 1925/26 (Bd. 24, 1925-1926) (3) Einband (-) Atomlehre von [Paul Peter] Ewald. Wintersemester 1925/1926 ([1]) Hauptteil I: Das allgemeine Bild vom Atombau (5) §1: Die Atomkonstanten für Materie und Elektrizität (5) §2 u. 3: Anzahl u. Verteilung der Elektronen im Atom (23) Hauptteil II: Die Bohr'sche Theorie der Atome und ihrer Spektren (31) §4: Theorie des H, He+ und B++ Atoms (31) §5: Serienspektren und Energiestufen (45) §6: Anregungs- und Ionisierungsspannungen; Normalzustände (59) Hauptteil III: Das periodische System (69) §7: Die Röntgenspektren (69) §8: Atomare Gesetzmäßigkeiten im periodischen System (77) Hauptteil IV: Moleküle und Molekülbildung (85) §9: Die Bandenspektren (85) §10: Molekülbildung durch angeregte Atome (95) §11: Polarität und Gestalt von Molekülen (101) Hauptteil V: Kristallchemie (107) §12 und 13: Gittertypen und Gitterstruktur (107) Hauptteil VI: Kernphysik (111) Farbinformation (-) Einband (-

Beitrag zur Kenntnis der Bionomie und Morphologie der Hanfblattlaus Phorodon cannabis Passerini, 1860 (Homoptera: Aphididae).

Feldbeobachtungen haben gezeigt, dass die Hanfblattlaus Phorodon cannabis Passerini in der Deutschen Demokratischen Republik weit verbreitet ist und überall dort vorkommt, wo Hanf angebaut wird. Massenbefall zeigt sich jedoch erst im August, weil die Entfaltung der Populationen in Folge des sehr schwachen Initialauftretens im Frühjahr verzögert wird. Die oviparen Weibchen legen ihre Eier vorzugsweise an die Samenkapseln der Hanfpflanze. Der kultivierte Hanf ist eine annuelle Pflanze und stellt in Mitteleuropa praktisch den einzigen Wirt dar, deshalb ist die Wirtsfindung für die aus den Eiern schlüpfenden Fundatrizen extrem erschwert. Fundatrizen wurden an Cannabis sativa Linnaeus sowohl im Feld gefunden wie im Insektarium aufgezogen. Die zwei auf die Fundatrix folgenden Generationen enthielten 78% und mehr Geflügelte. Die oviparen Weibchen sind Nachkommen sowohl von ungeflügelten wie von geflügelten Müttern. Alle Morphen von P. cannabis werden beschrieben. Sie werden mit den entsprechenden Morphen der Hopfenblattlaus Phorodon humuli (Schrank) verglichen.Field studies have shown the hemp aphid, Phorodon cannabis Passerini, to be widespread in the German Democratic Republic wherever hemp is cultivated. Mass infestation appaers, however, not earlier than in August because the buildup of the populations is retarted owing to the very small initial occurrence in spring. The oviparus females lay their eggs preferably on the seed capsules of the hemp plants. Cultivated hemp is an annual plant and practically the only host in Central Europe hence host finding is rendered extremely difficult for the hatching fundatrices. On Cannabis sativa Linnaeus fundatrices have been found in the field as well as reared in the insectary. The two generations following the fundatrix contained 78 per cent alatae or more. The oviparous females are the progeny of both apterous and alate mothers. All morphs of P. cannabis are described. They are compared with the corresponding morphs of the hop aphid, Phorodon humuli (Schrank)

UK copyright and the limits of UK music sampling

Music sampling is the act of taking a piece of an existing sound recording (the sample) and then using it in a new track. Sampling an original work without permission can infringe its copyright and therefore lead to lawsuits. There has still not been settled a single lawsuit regarding music sampling in the UK courts. It is therefore unclear to what extent music sampling can be used without infringing copyright. The overall aim of this paper is to establish the limits of music sampling and thereby determine whether music sampling could be used without infringing copyright laws. The literature review establishes the history and development of music sampling and determines the applicable laws. It also determines that there are two main exceptions to copyright; fair dealings and “de minimis,” which will be considered in the analysis. The methods used to analyse these two exceptions to copyright are the critical legal doctrine and the black letter analysis, which means that the analysis is based upon the statutes and case law. Due to the lack of UK case law, it is necessary to focus primarily upon case law from the US. Additionally, a survey was conducted to gather quantitative data regarding the use and perception of music sampling and its legality. In the analysis the two exceptions to copyright are considered. It is found that the fair dealings exception cannot be applied upon music sampling, while the “de minimis” exception can be applied, if the sample is not substantially similar to the original work. This meant that a sample could only be considered as “de minimis” in some very limited circumstances. Finally, it is showed how musicians believe that this current legal situation regarding music sampling can have a limiting effect upon their creativity. Overall, it is determined throughout this paper that the current copyright laws do not reflect the technological changes that has enabled musicians to unfold their creativity through “new” methods such as music sampling. It is therefore necessary that both the current law and their interpretation in courts are more relaxed in order not to damage the creative expression

Impact of long-term conventional and organic farming on the diversity of arbuscular mycorrhizal fungi

Previous work has shown considerably enhanced soil fertility in agroecosystems managed by organic farming as compared to conventional farming. Arbuscular mycorrhizal fungi (AMF) play a crucial role in nutrient acquisition and soil fertility. The objective of this study was to investigate the diversity of AMF in the context of a long-term study in which replicated field plots, at a single site in Central Europe, had been cultivated for 22years according to two "organic” and two "conventional” farming systems. In the 23rd year, the field plots, carrying an 18-month-old grass-clover stand, were examined in two ways with respect to AMF diversity. Firstly, AMF spores were isolated and morphologically identified from soil samples. The study revealed that the AMF spore abundance and species diversity was significantly higher in the organic than in the conventional systems. Furthermore, the AMF community differed in the conventional and organic systems: Glomus species were similarly abundant in all systems but spores of Acaulospora and Scutellospora species were more abundant in the organic systems. Secondly, the soils were used to establish AMF-trap cultures using a consortium of Plantago lanceolata, Trifolium pratense and Lolium perenne as host plants. The AMF spore community developing in the trap cultures differed: after 12months, two species of the Acaulosporaceae (A. paulinae and A. longula) were consistently found to account for a large part of the spore community in the trap cultures from the organic systems but were found rarely in the ones from the conventional systems. The findings show that some AMF species present in natural ecosystems are maintained under organic farming but severely depressed under conventional farming, indicating a potentially severe loss of ecosystem function under conventional farmin

Effects of resource depression on use of inexpensive and escalated aggressive behavior: experimental tests using Anna hummingbirds

To test whether alterations in aggressive behavior are responses to short-term resource depression, use of inexpensive and escalated territorial defense by Anna hummingbirds was analyzed as a function of the degree to which food could be depressed by foraging activities of territory owners and intruders. On depressible territories use of gorget display (a low cost defense) decreased and durations of chases increased as time since the previous feeding by owners increased. On non-depressible territories neither variable was significantly correlated with time since feeding. The percentage of intruders chased by owners was positively correlated with time since feeding on both depressible and nondepressible territories, but the magnitude of this trend decreased as food production increased. Departures from the territory tended to occur shortly after feeding on both types of territories, but this tendency was stronger on depressible territories.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46868/1/265_2004_Article_BF00343199.pd