bluuebunny/crossref_metadata_2025_split huggingface dataset:
Drought refuges affect algal recolonization in intermittent streams
Authors: Robson Belinda J. , Matthews Ty G. 
Published: July 2004

AbstractDrought refuges enable the biota of intermittent streams to survive dry periods, but their roles in sustaining algal assemblage structure and productivity are not known. This study determined the importance of two types of drought refuge (dry biofilm, permanent pools) for benthic algal regrowth in four intermittent streams in the Grampians National Park, Victoria, Australia. Dry biofilm was removed by scrubbing randomly chosen stones from two dry riffles in each of two streams with permanent pools and two streams without permanent pools. Algae were sampled from scrubbed and control stones at one, six and sixteen weeks after flow resumed. Removal of dry algal biofilm resulted in lower algal densities on stones from both stream types, and scrubbed stones had similar densities of algae after one week, regardless of the presence or absence of permanent pools. Algal density on stones exposed to both refuge types was more than an order of magnitude higher than the density on stones exposed to either one or neither refuge. The effects of biofilm removal on algal density were still apparent after six weeks of flow and assemblage composition differed between streams with and without permanent pools. Dry biofilm was an important drought refuge for algae in both stream types, but epilithic algal density in streams with permanent pools developed more rapidly than streams that were completely dry over summer. Loss of permanent pools from intermittent streams due to water abstraction may substantially reduce algal productivity after flow resumes, which may limit the supply of autochthonous carbon. Copyright © 2004 John Wiley & Sons, Ltd.
A research C# compiler
Authors: Hanson David R. , Proebsting Todd A. 
Published: July 2004

AbstractC# is the new flagship language in the Microsoft .NET platform. C# is an attractive vehicle for language design research not only because it shares many characteristics with Java, the current language of choice for such research, but also because it is likely to see wide use. Language research needs a large investment in infrastructure, even for relatively small studies. This paper describes a new C# compiler designed specifically to provide that infrastructure. The overall design is deceptively simple. The parser is generated automatically from a possibly ambiguous grammar, accepts C# source, perhaps with new features, and produces an abstract syntax tree, or AST. Subsequent phases—dubbed visitors—traverse the AST, perhaps modifying it, annotating it or emitting output, and pass it along to the next visitor. Visitors are specified entirely at compilation time and are loaded dynamically as needed. There is no fixed set of visitors, and visitors are completely unconstrained. Some visitors perform traditional compilation phases, but the more interesting ones do code analysis, emit non‐traditional data such as XML, and display data structures for debugging. Indeed, most usage to date has been for tools, not for language design experiments. Such experiments use source‐to‐source transformations or extend existing visitors to handle new language features. These approaches are illustrated by adding a statement that switches on a type instead of a value, which can be implemented in a few hundred lines. The compiler also exemplifies the value of dynamic loading and of type reflection. Copyright © 2004 John Wiley & Sons, Ltd.
Dynamic reconfiguration of CPU and WebSphere on IBM pSeries servers
Authors: Jann Joefon , Dubey Niteesh , Burugula R. S. , Pattnaik Pratap 
Published: July 2004

AbstractThis paper studies the effects that dynamic reconfiguration (DR) has on a WebSphere workload while CPUs are dynamically added to and removed from the underlying AIX instance. DR is a new technology available in AIX 5.2. This study shows that the resource allocations for a complex and function‐rich middleware system such as WebSphere can be efficiently and dynamically managed by the DR technology, without WebSphere having to explicitly accommodate for the DR features of the operating system. Copyright © 2004 John Wiley & Sons, Ltd.
Biegedrillknicken von Trägern mit einfach‐symmetrischen Profilen
Authors: Vayas Ioannis 
Published: July 2004

AbstractEin wesentliches Problem beim Nachweis von Trägern unter Momentenbeanspruchung stellt die Ermittlung des elastischen kritischen Moments für Biegedrillknicken dar. Im vorliegenden Beitrag werden einfache Formeln zur Ermittlung des kritischen Moments von gabelgelagerten Trägern angegeben. Die Formeln decken viele praktische Anwendungsfälle ab. Die Herleitung erfolgt durch Anwendung der Energiemethode und Lösung nach dem Ritz'schen Verfahren. Für die Verdrehungen werden eingliedrige Ansätze gemacht. Die Ergebnisse werden mit genaueren Lösungen unter Anwendung mehrgliedriger Ansätze verglichen. Der Vergleich zeigt, daß für die üblichen Abmessungen die Genaugkeit innerhalb akzeptabler Grenzen bleibt. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Der Berstdruck eines zylindrischen Stahlsilos unter Explosionsinnendruckbeanspruchung
Authors: Wasicek Manfred , Fischer Franz Dieter , Sabirov Ilshat , Kolednik Otmar 
Published: July 2004

AbstractBeim Füllen und Entleeren eines Silos kann es durch die Staubentwicklung des Lagerguts und das Vorhandensein einer Zündquelle zu einer Staubexplosion kommen, welche durch ihre Heftigkeit ein großes Risiko für die Anlage darstellt.Dieser Beitrag beschäftigt sich mit der druckstoßfesten Ausführung von Silos, welche dem zu erwartenden Explosionsdruck mit bleibenden Verformungen widersteht. Das Grenztragverhalten der einzelnen Schalenanteile des Silos, wie Zylinder, Kegel, Torus und Kugelkalotte, wird mit Hilfe der Plastizitätstheorie und dem Kriterium nach Considère bestimmt. Das Tragverhalten der Schalenübergänge wird mittels einer nichtlinearen Berechnung mit dem Finite‐Element‐Programm ABAQUS untersucht. Weiter werden die plastischen Grenzdrücke aufgrund von fehlerbehafteten Schweißnähten (Kerben und Risse) an den Schalenverbindungen mittels der Schädigungs‐ und Bruchmechanik bestimmt, wobei die Materialkennwerte aus den durchgeführten Versuchen verwendet wurden. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Einfluß der Auflagerpositionen auf die 1. Eigenfrequenz beim Euler‐Bernoulli‐Balken
Authors: Homann Stefan , Keye Stefan 
Published: July 2004

AbstractEs wird ein Verfahren vorgestellt, mit dem sich für einen Euler‐Bernoulli‐ Balken konstanter Länge die 1. Eigenkreisfrequenz als Funktion des Abstands der Auflager in analytisch geschlossener Form beschreiben läßt. Basierend auf der Annahme, daß die potentielle Energie der Eigenschwingungsform vom Abstand der Auflager unabhängig ist, wird die Eigenkreisfrequenz mit Hilfe des Rayleigh‐Quotienten näherungsweise bestimmt. Zur Abschätzung der Güte der Näherung wird ein Vergleich mit einer numerischen Lösung vorgenommen. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Fertigung und Montage des Messeturms in Rostock
Authors: Klimke Herbert , Stephan Sören , Essrich Reiner 
Published: July 2004

AbstractDieser Beitrag beschreibt die Realisierung eines Tensegrity‐Turms, der auf einem dreieckigen Grundriß aufgebaut und bei dem jedes Segment um 30° verdreht ist (Twistelement). Die Realisierung erfordert die Einhaltung ungewöhnlich kleiner Fertigungstoleranzen, insbesondere bei den Seilen, und ein konsistentes Konzept für den Toleranzausgleich. Ein Hauptproblem der Realisierung ist das Vorspannen der Seile, das durch gleichzeitiges Verschieben der drei Fußpunkte jedes Elements mit Hilfe von 100‐t‐Pressen gelöst wurde. Der Turm wurde aus den Twistelementen zunächst in zwei Teilen zusammengebaut und dann das obere Teil mit einem 170‐t‐Mobilkran auf das untere Teil gehoben. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Beulanalyse wellenförmiger Schalen veränderlicher Dicke
Authors: Shigematsu Tsunemi , Ohga Mitao , Hara Takashi 
Published: July 2004

AbstractIn der vorliegenden Arbeit wird die Stabilität für zwei Arten wellenförmiger Schalen mit dünnwandigen Querschnitten veränderlicher Dicke untersucht. Dabei besitzen die Krümmungen der kontinuierlichen Schalen ungleiche Richtungen. Bei der Herleitung der Õbertragungsmatrix werden der negative Krümmungsradius und der Õbertragungswinkel für wellenförmige Schalen eingeführt. Die Ergebnisse werden als Beulwerte und Beulformen mitgeteilt. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Zur Effizienz von Queraussteifungen und unteren Verbänden bei breiten Straßendeckbrücken
Authors: Unterweger Harald , Kaim Peter 
Published: July 2004

AbstractDer Beitrag behandelt verschiedene Variantenstudien zum Tragsystem einer mehrfeldrigen Straßendeckbrücke in Verbundbauweise mit Stützweiten von etwa 70 m im Zuge der notwendigen Verstärkung einer bestehenden Brücke. Ursprünglich handelt es sich um eine Autobahnbrücke mit zwei getrennten Tragwerken mit jeweils zwei Hauptträgern, die einen einzelligen Kastenquerschnitt bilden. Neben dieser Ausbildung wird eine Verbindung beider Tragwerke mit zusätzlichen Querverbänden und eine Ergänzung zu einem dreizelligen Kastenquerschnitt untersucht. Zu Vergleichszwecken erfolgt eine Berechnung für zwei isolierte Tragwerke mit offenem Querschnitt sowie deren Ergänzung mit durchlaufenden Querverbänden zu einem offenen Trägerrost. Weiterhin wird die Variation von Steifigkeit und Anzahl der Verbände für alle Systeme untersucht. Die Ergebnisse werden in Form von vertikalen Durchbiegungen sowie Einflußlinien und Beanspruchungen in repräsentativen Hauptträger‐ und Verbandsquerschnitten vergleichend dargestellt. Daraus ist die Effizienz der Queraussteifungen und unteren Verbände direkt ablesbar. Damit lassen sich für die sinnvolle Verstärkung von Autobahnbrücken mit zwei getrennten Tragwerken (offener Querschnitt oder Kastenquerschnitt) sowie auch für die sinnvollste Systemwahl bei Neubauten im Falle großer Fahrbahnbreiten, generelle Hinweise ableiten. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Biegedrillknickmomente und Eigenformen von Biegeträgern unter Berücksichtigung der Drehbettung
Authors: Kindmann Rolf , Muszkiewicz Reiner 
Published: July 2004

AbstractIn DIN 18800 [1] und im EC 3 wird das ideale Biegedrillknickmoment als Bezugsgröße für den Tragsicherheitsnachweis biegedrillknickgefährdeter Träger verwendet. Aus wirtschaftlichen Gründen ist es dabei vorteilhaft, die stabilisierende Wirkung angrenzender Bauteile zu berücksichtigen. In diesem Beitrag wird über die Ermittlung von MKi unter Berücksichtigung einer Drehbettung berichtet. Darüber hinaus wird gezeigt, welchen Funktionsverlauf die zugehörigen Eigenformen haben, da sie für Nachweise unter Ansatz von geometrischen Ersatzimperfektionen benötigt werden. Als Alternative zu Berechnungen mit Hilfe von EDV‐Programmen werden für ausgewählte baustatische Systeme Näherungsformeln angegeben, die die Ermittlung von MKi mittels Handrechnung ermöglichen. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Spatial hierarchical approach in community ecology: a way beyond high context‐dependency and low predictability in local phenomena
Authors: Noda Takashi 
Published: July 2004

AbstractPatterns and functioning of communities, which are determined by a set of processes operating at a large variety of spatial and temporal scales, exhibit quite high context‐dependency and low predictability at the fine spatial scales at which recent studies have concentrated. More attention to broader scale and across‐scale phenomena may be useful to search for general patterns and rules in communities. In this context, it is effective to incorporate hierarchical spatial scale explicitly into the experimental and sampling design of field studies, an approach referred to here as thespatial hierarchical approach, focusing on a particular assemblage in which biological interaction and species life history are well known. The spatial hierarchical approach can provide insight into the effects of scale in operating processes and answers to a number of important questions in community ecology such as: (1) detection of patterns and processes in spatiotemporal variability in communities, including how to explain the partitioning of pattern information of species diversity at a broad scale into finer scales, and the pattern of spatial variability of community properties at the finest spatial scale; (2) evaluation of changes in patterns observed in macroecology at finer scales; (3) testing of models explaining the coexistence of competing species; and (4) detection of latitudinal patterns in spatiotemporal variability in communities and their causal processes.
Latitudinal gradient of species diversity: multi‐scale variability in rocky intertidal sessile assemblages along the Northwestern Pacific coast
Authors: Okuda Takehiro , Noda Takashi , Yamamoto Tomoko , Ito Norihiko , Nakaoka Masahiro 
Published: July 2004

AbstractThis study examined the latitudinal gradient of species diversity of rocky intertidal sessile assemblages on the slopes of rocks along the Northwestern Pacific coast of Japan, located between 31°N and 43°N, by explicitly incorporating an hierarchical spatial scale into the monitoring design. The specific questions were to examine: (1) whether there is a latitudinal gradient of regional diversity, (2) how spatial components of the regional diversity (local diversity and turnover diversity) vary with latitude depending on spatial scale, and (3) whether the latitudinal gradient differs between different measures of species diversity, i.e. species richness and Simpson's diversity index. We measured coverage and the presence or absence of all sessile organisms in a total of 150 census plots established at five shores in each of six regions. The results showed that there were clear latitudinal gradients in regional species richness and in species turnover among shores. However, these patterns were not reflected in smaller‐scale local species richness. For Simpson's diversity index, there was no evidence of latitudinal clines either in regional diversity or in spatial components. These results suggest that relative abundance of common species does not vary along latitude, while the number of rare species increases with decreasing latitude.
Seed persistence of oilseed rape (Brassica napus): variation in transgenic and conventionally bred cultivars
Authors: GRUBER S. , PEKRUN C. , CLAUPEIN W. 
Published: July 2004

Seeds of oilseed rape (Brassica napus L.) can persist in the soil over several years by becoming secondarily dormant and can then germinate to create volunteer plants in following crops. As well as agricultural impacts caused by volunteers, gene dispersal in time – particularly from genetically modified cultivars – can be another undesirable consequence. Conventionally bred and transgenic seeds were tested in 2001 and 2002 in laboratory experiments, and in a field experiment, by burying seeds in the soil to determine the variation in dormancy and persistence capacity.In the conventional group of cultivars tested in the laboratory, the level of dormancy was 13–76% in 2001, and 3–76% with an extended group in 2002. The transgenic group of cultivars was 1–31% dormant. In the burial experiments the number of viable seeds recovered in the conventionally bred cultivars ranged from 34–90% in 2001, and 7–68% in 2002. In the same studies the transgenic cultivars developed persistence levels from 12–79% in 2001, and 46–67% in 2002. Since dormancy levels of conventionally bred cultivars from 2 harvest years in the laboratory tests correlated significantly (r=0·71), it appears that there is a genetic background to secondary dormancy. There was also a significant correlation (r=0·61 in 2001 and 0·80 in 2002) between the results from laboratory and burial experiments. This indicates that the laboratory approach can simulate the situation in the field. Ageing over 6 months decreased the capacity for seed persistence to about a fifth of the level shown when freshly harvested. As a consequence of ageing and environmental impacts on persistence, only seeds from the same location and harvest year should be used for testing genetic variability. The high genetic variability among currently available rape seed cultivars gives breeding strategies a good chance of ideotyping low persistence genotypes and minimizing the risk of gene dispersal in time.
Herbage production and animal performance on perennial ryegrass/white clover dairy pastures under alternative spring grazing managements
Authors: DA SILVA S. C. , HODGSON J. , MATTHEW C. , MATTHEWS P. N. P. , HOLMES C. W. 
Published: July 2004

Spring grazing managements which allowed some early inflorescence development, followed by hard grazing in order to remove the reproductive stems (designated ‘late control’), were compared with a conventional close grazing strategy (‘early control’) in three paddock-scale complete randomized block studies with dairy cows grazing perennial ryegrass/white clover pastures during consecutive years (1990–1993) in Palmerston North, New Zealand. Experiment 1 was designed to evaluate the timing of late control, Expt 2 to investigate the most suitable intensity of control, and Expt 3 tested different practical approaches to carrying out the late control management.Late control generated an average herbage production increase of 24% (750 kg DM/ha) in October and November (spring) and 22% (950 kg DM/ha) from January to April (summer–autumn) compared with the conventional management. The increase in herbage accumulation during spring was a consequence of greater perennial ryegrass reproductive development. Increased summer–autumn herbage accumulation after late control management was attributed to enhanced tillering activity and accumulation of perennial ryegrass. Effects on white clover production were inconsistent. Experiment 3 compared the effects of two practical late control strategies, involving either a short period of rapid rotational grazing or a simulation of increased stocking rate normally associated with forage conservation, on the milk production and forage intake of groups of cows in self-contained farmlet systems. During the control period, the reproductive state of the sward caused a small decrease in herbage digestibility. However, the extra herbage produced subsequently did not differ in digestibility from that produced on the conventionally managed sward and resulted in an increase of around 11·5% in total milk solids yield (fat, protein and lactose) per cow, particularly towards the end of the season (March and April).The late control spring grazing management strategy is a viable option for dairy farmers. It should coincide with the time of anthesis of ryegrass plants (late November–early December), and is more effectively achieved when forage conservation practices are used to augment grazing pressure in the grazed area of the farm.
Early Methodism
Authors: TABRAHAM BARRIE 
Published: July 2004

John Wesley. The evangelical revival and the rise of Methodism in England. By John Munsey Turner. Pp. x+214. Peterborough: Epworth Press, 2002. £14.95 (paper). 0 7162 0556 4Wesley and the Wesleyans. Religion in eighteenth-century Britain. By John Kent. Pp. vi+229. Cambridge: Cambridge University Press, 2002. £37.50 (cloth), £13.95 (paper). 0 521 45532 4; 0 521 45555 3A brand plucked from the burning. The life of John Wesley. By Roy Hattersley. Pp. vii+451+18 plates. London: Little, Brown, 2002. £20. 0 316 86020 4Mirror of the soul. The diary of an early Methodist preacher, John Bennet, 1714–1754. Edited and introduced by S. R. Valentine. Pp. xii+243 incl. 2 frontispieces. Peterborough: Methodist Publishing House, 2002. £15 (paper). 1 85852 216 1The tercentenary of John Wesley's birth saw the appearance of a whole crop of studies on various aspects of the Wesleys and early Methodism. Whether the current conversations between Methodists and Anglicans concerning the Covenanting Proposals is providing an additional spur remains to be seen. However, there can be no doubt that there is continued interest in the Wesleys and the way that Methodism developed, particularly in the eighteenth century, as the following four studies show in their very different ways.
Effects of cannabis and psychosis vulnerability in daily life: an experience sampling test study
Authors: VERDOUX H. , GINDRE C. , SORBARA F. , TOURNIER M. , SWENDSEN J. D. 
Published: July 2004

Background. Epidemiological findings suggest that cannabis use is a risk factor for the emergence of psychosis, and that the induction of psychotic symptoms in the context of cannabis use may be associated with a pre-existing vulnerability for psychosis. This study investigated in a non-clinical population the interaction between cannabis use and psychosis vulnerability in their effects on psychotic experiences in daily life.Method. Subjects (N = 79) with high or low levels of cannabis use were selected among a sample of 685 undergraduate university students. Experience sampling method (ESM) was used to collect information on substance use and psychotic experiences in daily life. Vulnerability to develop psychosis was measured using a clinical interview assessing the level of psychotic symptoms. Statistical analyses were performed using multilevel linear random regression models.Results. The acute effects of cannabis are modified by the subject's level of vulnerability for psychosis. Subjects with high vulnerability for psychosis are more likely to report unusual perceptions as well as feelings of thought influence than subjects with low vulnerability for psychosis, and they are less likely to experience enhanced feelings of pleasure associated with cannabis. There is no evidence that use of cannabis is increased following occurrence of psychotic experiences as would be expected by the self-medication model.Conclusion. Cannabis use interacts with psychosis vulnerability in their effects on experience of psychosis in daily life. The public health impact of the widespread use of cannabis may be considerable.
Cannabis dependence and psychotic symptoms in young people
Authors: FERGUSSON D. M. , HORWOOD L. J. , SWAIN-CAMPBELL N. R. 
Published: July 2004

Background. The aims of this research were to use data gathered over the course of a 21 year longitudinal study to examine the linkages between cannabis dependence at ages 18 and 21 and rates of psychotic symptoms taking into account previous symptom levels and other confounding factors.Method. Data were gathered during the course of the Christchurch Health and Development Study (CHDS). The CHDS is a longitudinal study of a birth cohort of 1265 children who have been studied from birth to age 21. As part of this study, data were gathered on cannabis dependence and psychotic symptoms at ages 18 and 21.Results. Young people meeting DSM-IV criteria for cannabis dependence had elevated rates of psychotic symptoms at ages 18 (rate ratio = 3.7; 95% CI 2.8–5.0; P<0.0001) and 21 (rate ratio = 2.3; 95% CI 1.7–3.2; P<0.0001). These associations were adjusted for previous psychotic symptoms and a range of other confounding factors using a generalized estimating equation model. This analysis showed that after adjustment for confounding factors, those meeting criteria for cannabis dependence still had an increased rate of psychotic symptoms (rate ratio = 1.8; 95% CI 1.2–2.6; P<0.005).Conclusions. The results show that the development of cannabis dependence is associated with increased rates of psychotic symptoms in young people even when pre-existing symptoms and other background factors are taken into account.