bluuebunny/crossref_metadata_2025_split huggingface dataset:
SWNT probed by multi‐frequency EPR and nonresonant microwave absorption
Authors: Corzilius B. , Dinse K.‐P. , Hata K. , Haluška M. , Skákalová V. , Roth S. 
Published: August 2008

AbstractIn addition to g = 2.00 signals seen frequently in EPR spectra of SWNT, signals at g = 2.07 of SWNT prepared by CVD were detected, exhibiting a Pauli susceptibility temperature dependence. This Pauli magnetism in combination with the large g shift is taken as evidence that these signals originate from itinerant electrons of metallic nanotubes. At temperatures below 150 K, a dominant narrow signal develops at g = 2.00. By applying multifrequency EPR up to 319 GHz, its inhomogeneous nature was confirmed. This signal is assigned to defects of the carbon network of the tubes.Comparing room temperature EPR spectra of CVD and arc‐grown SWNT, we found a much lower concentration of metallic tubes in arc material. No g = 2.07 signals of itinerant spins could be observed, which might be also caused by the high amount of residing catalyst. A drastic increase in nonresonant microwave absorption is observed below 10 K for both types of samples, if a threshold microwave power level is passed. In the same temperature range a drop in EPR intensity is also detected. These observations are taken as evidence for a transition into a superconducting phase of part of the sample. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A hybrid grid/particle filter for Lagrangian data assimilation. II: Application to a model vortex flow
Authors: Salman H. 
Published: August 2008

AbstractWe apply our hybrid filter to a regularised vortex model of a co‐rotating vortex pair. To illustrate the main advantages of our formulation over existing filters, we compare our method to the perturbed observation Ensemble Kalman filter and a particle filter with Gaussian resampling. Our numerical simulations show that both the hybrid and particle filters can track the true vortex positions even when tracer position data is assimilated infrequently into our model. In contrast, the Ensemble Kalman filter diverges in this parameter range as was recently observed in the more realistic shallow‐water model simulations of Salman et al. We have found that our hybrid method can track the true system with as few as 20 members for the vortex model flow. The particle filter on the other hand requires an ensemble comprising in excess of 160 members. The hybrid filter, therefore, provides one solution to the filter divergence problem that has been identified in recent work on Lagrangian data assimilation. Copyright © 2008 Royal Meteorological Society
Influence of regional factors on zooplankton structure in a saline lowland river: the Salado River (Buenos Aires province, Argentina)
Authors: Claps María C. , Gabellone Néstor A. , Neschuk Nancy C. 
Published: August 2008

AbstractKnowledge of regional factors influencing zooplankton structure in a semiarid river must include both the main channel and any tributaries in order to identify spatial and temporal patterns along with the main factor that affect the zooplankton community. Accordingly, seasonal samples were taken during 1997–1999 at 15 stations in the Salado River basin, where 172 species were identified (53 protozoans, 88 rotifers and 31 crustaceans). Conductivity and temperature optima and tolerances were calculated for the evident taxa. Different assemblages were recognized by cluster analysis, on the basis of their temperature and conductivity preferences. With respect to the zooplankton assemblages, three zones can be distinguished along the longitudinal axis of the basin: (1) the headwaters (the effluent from large saline shallow lakes), (2) the inter‐tributaries, and (3) the lower basin and associated shallow lakes. The spatial distribution of the assemblages was a result of the combined action of factors always promoting the dominance of rotifers. The influence of floodplain waters (backwater ponds, waterlogged depressions, flushing lakes) was attenuated progressively downstream, thus producing disadvantages for the crustaceans. The food availability and high nutrient concentrations related to land use in the headwaters favoured the co‐dominance of cladocerans and copepods along with the rotifers in that region. Copyright © 2008 John Wiley & Sons, Ltd.
Interactive effects of abiotic, hydrological and anthropogenic factors on fish abundance and distribution in natural run‐of‐the‐river shallow lakes
Authors: Rosso Juan José , Quirós Rolando 
Published: August 2008

AbstractEcological processes in lowland rivers are mostly dominated by hydrology and its interactions with other environmental factors. Fish–habitat relationships in rivers are also influenced by human impacts.In this study, we describe patterns of abundance and distribution of fish species in a group of natural lowland river lakes along spatial anthropogenic and abiotic gradients when four hydrologically different summers are compared. We also describe the proportion of the total variances in fish species abundances that can be accounted for by selected abiotic (water conductivity), hydrological (water residence time) and human activity‐derived (total phosphorus (TP) concentration and NO3:NH4) variables. Consequently, our main purpose is to explore how abiotic and anthropogenic factors interact to affect fish abundance and distribution together with consistent results across different hydrological conditions. We conclude with a briefly discussion of some management implications.The anthropogenic impacts on water quality, the extreme hydrological variability and the fluctuating abiotic environment affected fish abundance and distribution. Pampa inland silverside Odontesthes bonariensis was benefited from a less human disturbed environment with higher water residence time and total salinity, whereas species as Cyphocharax voga, Parapimelodus valenciennis and Cyprinus carpio found these conditions largely disadvantageous. On the other hand, while most species showed stronger—either negative or positive—response to anthropogenic, hydrological or abiotic factors Oligosarcus jenynsii was only slightly affected.This paper identified the ecological function of a lowland river under its natural flow regime. There are not many opportunities to study unmodified rivers worldwide. Therefore, our findings may help in assessment programmes of fish communities in flow altered and human disturbed aquatic ecosystems. Copyright © 2008 John Wiley & Sons, Ltd.
Simulating the hydrology and total dissolved solids (TDS) of an ephemeral river in South Africa for environmental water requirement determinations
Authors: Hughes D. A. 
Published: August 2008

AbstractExisting hydrological approaches to support the determination of environmental water requirements (EWRs) were largely developed for perennial rivers and may not be applicable to ephemeral rivers, where the quantity and quality dynamics of pool storage and frequency of connection can be more important than flow rates. The current understanding of semi‐arid hydrological processes and how best to apply hydrological models in ephemeral systems is less well developed than for more humid regions. The paper reports on the application of monthly and daily time‐step rainfall‐runoff models to simulating the hydrology (including pool storage) of the Seekoei River basin, a tributary of the Orange River in the Northern Province, South Africa. The hydrological response of the basin is spatially variable, a relatively small part of the basin generating a large proportion of the total stream flow. The outputs from the hydrological models have been used as inputs to a simple water quality mass balance model designed to simulate the total dissolved solids (TDS) of both flow and pool storage. The results from both the water quantity and quality models are encouraging when compared with the available observed data. While there are no data to confirm the simulation results at sub‐basin scales, they do appear to be conceptually acceptable. The conclusion is that the results are adequate to support ecological studies in the determination of EWRs. Copyright © 2008 John Wiley & Sons, Ltd.
Does ice matter? Site fidelity and movements by Atlantic salmon (Salmo salar L.) parr during winter in a substrate enhanced river reach
Authors: Linnansaari Tommi , Alfredsen Knut , Stickler Morten , Arnekleiv Jo Vegar , Harby Atle , Cunjak Richard A. 
Published: August 2008

AbstractIn‐stream habitat enhancement is a common remedial action in rivers where degradation/lack of suitable fish habitat can be diagnosed. However, post‐project monitoring to assess the response of the biota to modification is rare particularly during winter. We conducted in situ monitoring during the winters of 2004–2006 in the regulated Dalåa River, central Norway, in order to determine if winter habitat requirements of Atlantic salmon (Salmo salar L.) parr were realized in an enhanced (substrate and mesohabitat modification) reach. In total, 140 parr were marked with passive integrated transponder (PIT) tags and the fish were followed by carrying out active tracking surveys under variable ice conditions throughout the winter. Highest emigration (44%) occurred before ice formation started. Emigration was reduced after ice formed and was largely offset by parr re‐entering the enhanced area. Dispersal into the non‐enhanced, small substrate control area was observed only when the study reach was ice covered, and no parr were subsequently encountered in the control section after ice had melted. In the enhanced area, declining water temperature and surface ice conditions did not affect the spatial distribution of the resident salmon parr at the studied scale. Areas with ‘solid’ anchor ice precluded access for salmon parr whilst areas with ‘patchy’ anchor were used throughout the winter. Our results indicate that surface ice creates conditions that allow salmon parr to use stream habitats that otherwise provide only a limited amount of in‐stream cover. Ice processes should be taken into consideration when habitat enhancement projects are carried out and subsequently assessed for effectiveness. Copyright © 2008 John Wiley & Sons, Ltd.
Functional trait differences between extant exotic, native and extinct native plants in the Hunter River, NSW: a potential tool in riparian rehabilitation
Authors: Kyle Garreth , Leishman Michelle R. 
Published: August 2008

AbstractRiparian and riverine systems around the world are subject to human mediated degradation. It is increasingly recognized that rehabilitation of these systems is important to retain biodiversity and important ecosystem services. Plant functional traits represent a potentially useful but underutilized tool in the restoration or rehabilitation of ecosystems such as riparian systems. This study uses a functional trait approach to provide insight into the changes in ecosystem function that have occurred with the loss of native plant species and their replacement by exotics. We examined the plant functional traits associated with extinct native, extant native and extant exotic species in the riparian margin of the Hunter River, New South Wales, Australia. Comparisons of 11 traits were conducted using univariate (analysis of variance and χ
2) and multivariate (principal component analysis and analysis of similarity) methods. Both extant native and extant exotic species had traits associated with a short lived, ruderal strategy: high specific leaf area (SLA), soft leaves, herbaceous growth forms and therophyte life form. In contrast, extinct native species had traits such as low SLA, tough leaves, tree and shrub growth form and phanerophyte life form. This shift in plant trait assemblages associated with the transition from a native to predominately exotic flora has important implications for ecosystem processes in this riverine system. We suggest that such a functional trait approach can be integrated with knowledge of other ecosystem components to provide an understanding of ecosystem function that can be used to guide rehabilitation initiatives. Copyright © 2008 John Wiley & Sons, Ltd.
Sharp thresholds for constraint satisfaction problems and homomorphisms
Authors: Hatami Hamed , Molloy Michael 
Published: August 2008

AbstractWe determine under which conditions certain natural models of random constraint satisfaction problems have sharp thresholds of satisfiability. These models include graph and hypergraph homomorphism, the (d,k,t)‐model, and binary constraint satisfaction problems with domain size three. © 2008 Wiley Periodicals, Inc. Random Struct. Alg., 2008
A percolating hard sphere model
Authors: Cotar Codina , Holroyd Alexander E. , Revelle David 
Published: August 2008

AbstractGiven a homogeneous Poisson point process in ℝd, Häggström and Meester (Random Struct Algorithms 9 (1996) 295–315) asked whether it is possible to place spheres (of differing radii) centred at the points, in a translation‐invariant way, so that the spheres do not overlap but there is an unbounded component of touching spheres. We prove that the answer is yes in sufficiently high dimension. © 2008 Wiley Periodicals, Inc. Random Struct. Alg., 2009
Targeted Delivery of Nanoparticles Bearing Fibroblast Growth Factor‐2 by Ultrasonic Microbubble Destruction for Therapeutic Arteriogenesis
Authors: Chappell John C. , Song Ji , Burke Caitlin W. , Klibanov Alexander L. , Price Richard J. 
Published: August 2008

AbstractTherapeutic strategies in which recombinant growth factors are injected to stimulate arteriogenesis in patients suffering from occlusive vascular disease stand to benefit from improved targeting, less invasiveness, better growth‐factor stability, and more sustained growth‐factor release. A microbubble contrast‐agent‐based system facilitates nanoparticle deposition in tissues that are targeted by 1‐MHz ultrasound. This system can then be used to deliver poly(D,L‐lactic‐co‐glycolic acid) nanoparticles containing fibroblast growth factor‐2 to mouse adductor muscles in a model of hind‐limb arterial insufficiency. Two weeks after treatment, significant increases in both the caliber and total number of collateral arterioles are observed, indicating that the delivery of nanoparticles bearing fibroblast growth factor‐2 by ultrasonic microbubble destruction may represent an effective and minimally invasive strategy for the targeted stimulation of therapeutic arteriogenesis.
Innovative Stahltragwerke für das Museo del Acero in Mexiko
Authors: Sobek Werner , Schmid Angelika , Heinlein Frank 
Published: August 2008

AbstractDas ehemalige Industriegelände “Parque Fundidora” in Monterrey (Mexiko) ist in den letzten Jahren zu einem Museumsstandort mit Unterhaltungsangeboten umgewandelt worden. In diesem Rahmen wurde ein stillgelegtes Stahlwerk zu einem Stahl‐Museum umgebaut, in dem Vergangenheit und Gegenwart der Stahlindustrie in der Region aufgezeigt werden (Bild 1). Das Museum öffnete im Herbst 2007 seine Tore für die Öffentlichkeit und erhielt aufgrund seiner großen baulichen Qualitäten sofort den Titel “Monumento Nacional de Mexico”. Für die Errichtung des Museo del Acero wurde zum einen der vorhandene Baukörper des alten Stahlwerks restauriert und über Laufstege von außen zugänglich gemacht. Zum anderen wurde ein Neubau erstellt, der auf Höhe des Erdgeschosses an den Bestand anschließt und im weiteren Verlauf aufgrund der Geländetopographie teilweise unterirdisch liegt. Wichtiger Teil des Neubaus sind zwei filigrane Sonderstrukturen aus Stahl – das facettierte Dach der sogenannten Stahlgalerie und eine frei schwebende Wendeltreppe – sowie eine leicht und transparent anmutende Glasfassade. Diese Tragwerke werden im folgenden Artikel beschrieben.
Große Teleskope und der Brückenbau
Authors: Kärcher Hans Jürgen 
Published: August 2008

AbstractIn den letzten Jahren hat die Entwicklung von extrem großen bodengebundenen optischen Teleskopen einen unvorhergesehenen Aufschwung genommen. Die technologische Entwicklung wird vorangetrieben durch die immer komplexere aktive und adaptive Optik. Dabei gewinnt aber auch die Gestaltung der Teleskopstruktur immer stärker an Bedeutung – sie ist schließlich das Rückgrat für die Optik, und hat entsprechenden Einfluss auf die Teleskopeigenschaften, insbesondere aber auch auf die Kosten.Strukturmechanik selbst ist eine sehr alte Kunst, beginnend vor langer Zeit mit dem Bau von Brücken oder gotischen Kathedralen. Grundlage dieser Kunst ist das Verständnis für Kräfte, Lastpfade, Gewicht und Balance sowie Beanspruchung und damit verbundene Verformungen. Der Beitrag entwickelt strukturmechanisches Verständnis für die Bauteile eines großen Teleskops (Tubus, Alidade) auf Grundlage des Denkens der Brückenbauer. Aktuelles Beispiel ist der Konzeptentwurf für ein 42 m Extrem Large Telescope (ELT).
Schwebefähren: Triumphbögen zwischen Festland und Meer – Versuch einer Chronologie
Authors: Stiglat Klaus 
Published: August 2008

AbstractDie Schwebefähren waren eine überwiegend hängebrückenartige Konstruktion mit fest installierten Fahrgeräten, die dem Personen‐ und Gütertransport in See‐ und Flusshäfen dienten wie auch für innerbetriebliche Transporte in Industrieanlagen genutzt wurden.Es wird versucht, ihre Entstehungsgeschichte chronologisch zu beschreiben und die wichtigsten technischen Merkmale und ihre Veränderungen aufzuzeigen. Insgesamt werden siebzehn bedeutende Fähren aus den Jahren 1893 bis 1920 besprochen.
Beurteilung bestehender Stahltragwerke: Empfehlungen zur Abschätzung der Restnutzungsdauer
Authors: Kühn Bertram , Helmerich Rosemarie , Nussbaumer Alain , Günther Hans‐Peter , Herion Stefan 
Published: August 2008

AbstractDie zunehmende Bedeutung der Nachhaltigkeit im Bauwesen wird in Zukunft das Bauen im Bestand gegenüber Neubauten in den Vordergrund rücken. Dies gilt auch für den Brückenbau, wo das Qualitätsmanagement seit langem Brücken von ihrem Entstehungsgang über den Betrieb bis in die Entsorgung begleitet.Die starke Vergrößerung der Frachtvolumina für Straße und Schiene und die zunehmende Überalterung des Brückenbestandes fragen danach, ob die bestehenden Brücken für die veränderten Betriebsbedingungen noch geeignet sind und wie sie und ob sie dafür instandgesetzt werden könnten.Für die erforderlichen Instandhaltungs‐ und Instandsetzungsmaßnahmen oder einen eventuellen Ersatz durch einen Neubau ist aber die Frage der Restnutzungsdauer von entscheidender Bedeutung. Es ist daher nicht von ungefähr, dass sich Baulast‐träger auf nationaler und internationaler Ebene frühzeitig zusammengetan haben, um nach geeigneten Methoden der Bestimmung der Sicherheit und Restnutzungsdauer bestehender Brücken zu forschen. Auch die internationalen technisch‐wissenschaftlichen Verbände wie EKS und fib sowie die Standard‐Organisationen ISO und CEN sind der Frage eines internationalen Austauschs und der Vereinheitlichung der Methoden nachgegangen.Für Stahlbrücken hat insbesondere das technische Komitee6 – Ermüdung – der EKS Anregungen aufgegriffen, aus den verschiedenen nationalen Erfahrungen und dem vorhandenen Wissen technische Empfehlungen für die Beurteilung bestehender Stahlbrücken zu entwickeln [1], die sich als Grundlage für die von CEN/TC 250 – das CEN‐Komitee für die Bearbeitung der Eurocode – geplante Erweiterung der Eurocode zur Instandhaltung und Instandsetzung des Brückenbestandes eignen.Das Ergebnis ist ein technisch‐wissenschaftlicher Bericht, der im Rahmen der Zusammenarbeit der europäischen Kommission (DG‐Research – Joint Research Centre JRC) mit der EKS als Basispapier für eine zukünftige Eurocode‐Erweiterung veröffentlicht wurde und schon jetzt als Empfehlung für eine Vorgehensweise nach dem Stand der Technik verwendet werden kann.Der vorliegende Beitrag behandelt die Grundzüge dieses Berichtes [1], der vom e‐bookshop der Kommission kostenfrei herunter geladen werden kann.
Graded response model based on the logistic positive exponent family of models for dichotomous responses
Authors: Samejima Fumiko 
Published: August 2008

Samejima (Psychometrika 65:319–335, 2000) proposed the logistic positive exponent family of models (LPEF) for dichotomous responses in the unidimensional latent space. The objective of the present paper is to propose and discuss a graded response model that is expanded from the LPEF, in the context of item response theory (IRT). This specific graded response model belongs to the general framework of graded response model (Samejima, Psychometrika Monograph, No. 17, 1969 and No. 18, 1972; Handbook of modern item response theory, Springer, New York, 1997; Encyclopedia of Social Measurement, Academic Press, San Diego, 2004), and, in particular to the heterogeneous case (Samejima, Psychometrika Monograph, No. 18, 1972). Thus, the model can deal with any number of ordered polytomous responses, such as letter grades (e.g., A, B, C, D, F), etc.For brevity, hereafter, the model will be called the LPEF graded response model, or LPEFG. This model reflects the opposing two principles contained in the LPEF for dichotomous responses, with the logistic model (Birnbaum, Statistical theories of mental test scores, Addison Wesley, Reading, 1968) as their transition, which provide a reasonable rationale for partial credits in LPEFG, among others.
Variation in Fatty Acid Composition in Muscle and Heart Tissues among Species and Populations of Tropical Fish in Lakes Victoria and Kyoga
Authors: Kwetegyeka Justus , Mpango George , Grahl‐Nielsen Otto 
Published: August 2008

AbstractThe composition of the fatty acids in muscle and heart tissue of seven fish species, Nile perch (Lates niloticus), Nile tilapia (Oreochromis niloticus), marbled lungfish (Protopterus aethiopicus), African catfish (Clarias gariepinus), Lake Victoria squeaker (Synodontis victoriae),Bagrus docmas, andTilapia zilli,from two locations in Lake Kyoga and one location in Lake Victoria was chemometrically determined. The muscle tissue was very lean, with an average of 3.4 mg total fatty acids per g tissue. The lipid level in the heart tissue was approximately five times higher than in the muscle tissue, with an average of 15.5 mg total fatty acids per g tissue. The n‐3/n‐6 level in the muscles was 1.7 ± 0.7 and in the heart tissue 1.0 ± 0.4. The muscle tissue contained an average of 46 mg cholesterol per 100 g, and the heart tissue contained about five times as much. Plasmalogens were detected in 7–8% of the amounts of total fatty acids in both muscle and heart tissue. The seven species had large differences (P < 0.05) in the fatty acid composition for both muscle and heart tissue. Within the species there were differences between fish from the populations in the three locations, although the population differences were smaller than the species differences. These differences appear to be controlled more closely by genetics/transcriptomics than by the diet.
100 Jahre Hardy-Weinberg-Gleichgewicht
Authors: Aichinger E. , Grimm T. 
Published: August 2008

Zusammenfassung
Vor 100 Jahren veröffentlichten Godfrey H. Hardy und Wilhelm Weinberg in unabhängigen Publikationen die Formel, die heute das grundlegende Gesetz für die Berechnungen der Populationsgenetik darstellt. Im vorliegenden Artikel sollen die Epoche, die diesem Gesetz vorausging, geschildert und die Umstände, die seine Entstehung begleiteten, beleuchtet werden. Weiterhin sollen die Forscher genannt werden, die durch ihre Arbeit ebenfalls dieser speziellen Formel auf der Spur waren und als Wegbereiter des Hardy-Weinberg-Gleichgewichts gelten dürfen.