bluuebunny/crossref_metadata_2025_split huggingface dataset:
Control of cracking in composite bridge decks in regions in biaxial tension
Authors: Johnson Roger P. 
Published: December 2011

AbstractDeck slabs of bridges of composite construction can in places be stressed in biaxial tension throughout their thickness. Rules for control of crack width in codes such as EN 1994‐2 are based on tests in uniaxial tension. Crack‐width measurements are reported from tests in 1977 on slabs in biaxial tension, acting as flanges of composite beams. A theoretical model for prediction of crack width is explained, and a method is given for applying the rules of EN 1994‐2 to biaxial tension. It gives results slightly more conservative than characteristic values deduced from the test results.Rissbreitenbeschränkung in Bereichen unter zweiachsialer Zugbeanspruchung für Fahrbahnplatten von VerbundbrüKen. Fahrbahnplatten von Verbundbrücken können teilweise über ihre gesamte Dicke durch zweiachsiale Zugbeanspruchungen belastet werden. Regelungen zur Rissbreitenkontrolle in Normen wie EN 1994‐2 beruhen auf Versuchen unter einachsialer Beanspruchung. Zu Versuchen aus dem Jahr 1977 liegen Ergebnisse von Rissbreiten‐Messungen an Platten unter zweiachsialer Beanspruchung vor, bei denen die Platten als Gurte von Verbundträgern wirkten. Es wird ein theoretisches Modell zur Vorhersage von Rissbreiten erläutert und eine Methode zur Anwendung der Vorschriften der Norm EN 1994‐2 auf zweiachsige Zugbeanspruchung vorgestellt. Die Ergebnisse des Modells sind etwas konservativer als die charakteristischen Werte, die aus den Versuchen ermittelt wurden.
Membranwirkung von Verbunddecken bei Brand – Numerische Untersuchungen
Authors: Schaumann Peter , Sothmann Jörg , Mensinger Martin , Stadler Martin 
Published: December 2011

AbstractIm Brandfall zeigen Verbundträger‐Decken‐Systeme ein gutmütiges Tragverhalten. Durch große Verformungen können Membrankräfte aktiviert und so Tragreserven genutzt werden. Nach derzeit in Deutschland geltenden Vorschriften kann dieses Tragverhalten im brandschutztechnischen Nachweis jedoch nicht ohne Weiteres berücksichtigt werden. Es ist Stand der Technik, dass das Gesamttragwerk gedanklich in einzelne Bauteile zerlegt wird und diese einzeln brandschutztechnisch nachgewiesen werden. Im System werden einige Nebenträger im Brandfall jedoch nicht zum Lastabtrag benötigt. Sie könnten dementsprechend gegen eine Brandeinwirkung ungeschützt ausgeführt werden. In Großbritannien und der Schweiz wird die Membranwirkung von Verbunddecken im Brandfall mit dem Verfahren nach Bailey ([1] bis [5]) bereits genutzt. Um das Verfahren auch in Deutschland anwenden zu können, bedarf es noch einiger eingehender Untersuchungen. Im Rahmen eines gemeinsamen Forschungsvorhabens des Lehrstuhls für Metallbau der Technischen Universität München und des Instituts für Stahlbau der Leibniz Universität Hannover werden diesbezüglich Untersuchungen durchgeführt. Das Projekt wird vom DASt und der AiF gefördert. In [6] wurde der Stand der Technik und die Idee der Membranwirkung allgemein bereits vorgestellt. In [7] sind die Versuchsaufbauten und Ergebnisse näher beschrieben worden. Dieser Beitrag konzentriert sich auf die numerischen Untersuchungen im Rahmen des Forschungsprojektes.Membrane action of composite slabs in fire – Numerical investigation. In case of fire composite beam slab systems show a very good behaviour. Due to large deformations membrane forces are activated inside the slab and thus, load bearing capacity reserves can be used. German building regulations divide the supporting structure in fictive structural members. Each member must fulfil the requirements even though it is not necessary for the load transfer in the system. Secondary beams are not necessary at elevated temperatures and can be left unprotected. In Great Britain and Switzerland membrane action is already used to design slab systems in fire ([1] to [5]). To enable such design rules in Germany further investigations are required. For this reason a research project was initiated by the authors. The project is supported by the DASt and AiF. In [6] the state of research and the idea of membrane action are already described. The experimental set‐up and results are shown in [7]. In this paper the numerical investigations of the project are presented.
Vorschläge für eine neue Stahlbau‐Profilreihe für Kranbahnträger
Authors: Weber Tim 
Published: December 2011

AbstractDie statische Berechnung von Kranbahnträgern verlangt bereits für geringe Kranbahnträgerbelastungen unverhältnismäßig große Querschnitte für die Doppel T‐Träger. Das wiederum ergibt die eindeutige Aussage, dass mit dieser Stahlbau‐Profilreihe keine optimierbaren Querschnitte bei anzustrebender Grundforderung nach minimaler Eigenmasse erzielbar sind. Im Folgenden wird eine eigenständige Stahlbau‐Profilreihe für Kranbahnträger vorgeschlagen. In der Praxis wäre es somit für den Bau von Kranbahntragwerken in Abhängigkeit von Belastung und Kranbahnlänge möglich, den benötigten Querschnitt aus dieser neuen Stahlbau‐Profilreihe auszuwählen und damit die erforderliche Eigenmasse signifikant zu reduzieren. Auch für den Stahlhochbau würden sich Einsatzmöglichkeiten für diese Stahlbau‐Profilreihe ergeben. Ihre Querschnittsformen sind in den Bildern 1 und 2 dargestellt.Eine Patentanmeldung für die genannte neue Stahlbau‐Profilreihe liegt dem Deutschen Patent‐ und Markenamt bereits vor [1]. Es wird angestrebt, das bestehende Prioritätsdatum der deutschen Patentanmeldung zu nutzen und die eingereichte Patentbeschreibung auf eine europäische oder internationale PCT‐Anmeldung auszuweiten.
Verformungsverhalten von Slim‐Floor Trägern
Authors: Hauf Gunter , Kuhlmann Ulrike 
Published: December 2011

AbstractVerbundflachdeckenträger (Slim‐Floor Träger) werden aufgrund der vergleichsweise großen Schlankheit in sehr vielen Fällen durch den Verformungsnachweis bestimmt. Das Verformungsverhalten dieser Träger wird hierbei maßgeblich durch die große Biegesteifigkeit des Betongurtes und dessen Rissbildung im Feldbereich, für durchlaufende Trägersysteme auch im Stützbereich, beeinflusst. Rechnerisch spiegelt sich die Biegsteifigkeit in der angenommenen mittragenden Breite des Betongurtes wider. Im vorliegenden Beitrag wird daher das experimentelle und analytische Verformungsverhalten von Slim‐Floor Trägern unter Berücksichtigung der Biegetragwirkung und der Rissbildung des Betongurtes untersucht. Auf Basis von Versuchen und den Ergebnissen einer umfangreichen Parameterstudie mit einem neuen analytischen Berechnungsmodell wird ein Vorschlag zur quasi‐elastischen Verformungsberechnung entwickelt, mit dessen Hilfe eine realistische Durchbiegungsberechnung von Slim‐Floor Trägern als ein‐ und zweifeldrige Systeme möglich ist.Deflection behaviour of slim‐floor girders. Due to the high slenderness of this construction type composite slim‐floor sections are often determined by the deflection design. The girder deflection is mainly influenced by the bending stiffness of the concrete chord as well as the cracking behaviour in the span and for continuous girder also at the support area. For the calculated girder stiffness and deflection the assumed effective width of the concrete chord is of importance. Therefore the present paper deals with investigations on the deflection behaviour of slim‐floor girders taking into account the bending state and the cracking of the concrete. Based on experimental investigations the analysis of results of a wide‐ranging parametric study by means of a new analytical non‐linear calculation model leads among others to a proposal for a quasi‐elastic calculation method of the deflections of single span and two span slim‐floor girders.
Novel approaches for drug delivery systems in nanomedicine: effects of particle design and shape
Authors: Daum Nicole , Tscheka Clemens , Neumeyer Andrea , Schneider Marc 
Published: December 2011

AbstractThe identification of novel drug candidates for the treatment of diseases like cancer, infectious diseases, or allergies (especially asthma) assigns new tasks for pharmaceutical technology. With respect to drug delivery several problems occur such as low solubility and hence low bioavailability or restriction to inconvenient routes of administration. Nanotechnological approaches promise to circumvent some of these problems, therefore being well suited for future applications as nanomedicines. Furthermore, efficient and sufficient loading is a critical issue that is approached through mesoporous particles and/or through nonspherical particles both offering larger volumes and surfaces. Special interest is laid on the effect of shape of particulate materials on the body and related physiological mechanisms. The modified response of biological systems on different shapes opens a new dimension to adjust particle system interaction. Finally, the biological response to these systems will determine the fate with respect to their therapeutic value. Therefore, the interaction pattern between nonspherical particulate materials and biological systems as well as the production processes are highlighted. WIREs Nanomed Nanobiotechnol 2012, 4:52–65. doi: 10.1002/wnan.165This article is categorized under:

Therapeutic Approaches and Drug Discovery > Emerging Technologies
Nanotechnology Approaches to Biology > Nanoscale Systems in Biology
Diagnosis of Fragile X Syndrome: A Qualitative Study of African American Families
Authors: Visootsak Jeannie , Charen Krista , Rohr Julia , Allen Emily , Sherman Stephanie 
Published: December 2011

AbstractFragile X syndrome (FXS) is an inherited genetic condition with critical consequences to the proband and family members at all levels in the generations. Although evidence demonstrates that the rates of diagnosis for FXS are the same in all racial groups, age of diagnosis in African American children has been reported to occur later than in Caucasian children. Additionally, African American families are seriously under‐represented in existing FXS research studies. As such, it is important to understand the possible disparities in the underlying factors to receiving a diagnosis in African American families with FXS. Herein, a qualitative approach was adopted to describe the overall FXS diagnosis experiences (pre‐diagnosis, diagnosis, and post‐diagnosis stages) of a convenience sample of 10 African American mothers. We identified three major findings among our participants: (1) FXS testing is not ordered immediately once a parent expresses concerns of developmental delays to the pediatricians, (2) the diagnosis is sometimes delivered in an insensitive manner with information often being outdated and unbalanced towards negative aspects, (3) communication issues among family members exists once the diagnosis is discovered. Although these qualitative data may not be representative of the whole group, these findings have significant implications for genetic counseling and our understanding in providing support and advocacy for African American families with FXS.
Future of Psychometrics: Ask What Psychometrics Can Do for Psychology
Authors: Sijtsma Klaas 
Published: December 2011

I address two issues that were inspired by my work on the Dutch Committee on Tests and Testing (COTAN). The first issue is the understanding of problems test constructors and researchers using tests have of psychometric knowledge. I argue that this understanding is important for a field, like psychometrics, for which the dissemination of psychometric knowledge among test constructors and researchers in general is highly important. The second issue concerns the identification of psychometric research topics that are relevant for test constructors and test users but in my view do not receive enough attention in psychometrics. I discuss the influence of test length on decision quality in personnel selection and quality of difference scores in therapy assessment, and theory development in test construction and validity research. I also briefly mention the issue of whether particular attributes are continuous or discrete.
Applying evolutionary computation to mitigate uncertainty in dynamically-adaptive, high-assurance middleware
Authors: McKinley Philip K. , Cheng Betty H. C. , Ramirez Andres J. , Jensen Adam C. 
Published: December 2011

Abstract
In this paper, we explore the integration of evolutionary computation into the development and run-time support of dynamically-adaptable, high-assurance middleware. The open-ended nature of the evolutionary process has been shown to discover novel solutions to complex engineering problems. In the case of high-assurance adaptive software, however, this search capability must be coupled with rigorous development tools and run-time support to ensure that the resulting systems behave in accordance with requirements. Early investigations are reviewed, and several challenging problems and possible research directions are discussed.
Transient Taylor–Aris dispersion for time-dependent flows in straight channels
Authors: Vedel Søren , Bruus Henrik 
Published: December 2011

AbstractTaylor–Aris dispersion, the shear-induced enhancement of solute diffusion in the flow direction of the solvent, has been studied intensely in the past half century for the case of steady flow and single-frequency pulsating flows. Here, combining Aris’s method of moments with Dirac’s bra–ket formalism, we derive an expression for the effective solute diffusivity valid for transient Taylor–Aris dispersion in any given time-dependent, multi-frequency solvent flow through straight channels. Our theory shows that the solute dispersion may be greatly enhanced by the time-dependent parts of the flow, and it explicitly reveals how the dispersion coefficient depends on the external driving frequencies of the velocity field and the internal relaxation rates for mass and momentum diffusion. Although applicable to any type of fluid, we restrict the examples of our theory to Newtonian fluids, for which we both recover the known results for steady and single-frequency pulsating flows, and find new, richer structure of the dispersion as function of system parameters in multi-frequency systems. We show that the effective diffusivity is enhanced significantly by those parts of the time-dependent velocity field that have frequencies smaller than the fluid momentum diffusion rate and the solute diffusion rate.
‘The Modern Magic Carpet’: Wireless radio in interwar colonial Singapore
Authors: AI LIN CHUA 
Published: December 2011

AbstractWireless radio broadcasting in colonial Singapore began with amateur organizations in the early 1920s, followed by commercial ventures and, finally, the establishment of a monopoly state broadcasting station. Listeners followed local broadcasting as well as international short wave radio. Both participants in and the content of radio reflected the multiracial, cosmopolitan make-up of a colonial port city which functioned through the lingua franca of English. The manner in which early broadcasting developed in Singapore sheds light on the creation of different imagined communities and the development of civil society. There was an increasing presence of non-Europeans, women, and youth, many of whom were drawn by the mystique of this new technology. Wireless radio also brought about a transformation in the public soundscape. These themes contribute to our understanding of the global history of radio as well as the nature of colonial societies within the British empire.
Response of guanacosLama guanicoeto changes in land management in Península Valdés, Argentine Patagonia: conservation implications
Authors: Burgi María Virginia , Marino Andrea , Rodríguez María Victoria , Pazos Gustavo , Baldi Ricardo 
Published: December 2011

AbstractThe guanacoLama guanicoewas the only large native herbivore widely distributed across Patagonia until the introduction of domestic sheepOvis aries. Guanacos have declined because of competition with sheep for forage, high hunting pressure and habitat degradation. Península Valdés is a protected area where sheep ranching is the predominant activity. A ranch formerly dedicated to sheep production was converted into a private wildlife reserve, from which all the sheep were removed in 2005. We studied changes in guanaco abundance inside and outside the reserve after sheep removal, and also plant cover of various vegetation types. We found that guanaco abundance was higher inside than outside the reserve, and increased by three-fold within 3 years. Total plant cover and grass cover were higher inside than outside the reserve. Our results showed that guanacos reacted rapidly to changes in management, and suggest that even at a high density guanacos would not be as damaging to the vegetation as sheep. Although management changes resulted in significant changes in guanaco abundance locally, the size of a protected area influences the persistence of wild populations. A large herbivore such as the guanaco needs to be managed across large areas. We believe it is necessary to implement a management plan for Península Valdés that allows for the coexistence of sustainable livestock production and healthy wildlife populations.
Range-wide declines of a key Neotropical ecosystem architect, the Near Threatened white-lipped peccaryTayassu pecari
Authors: Altrichter Mariana , Taber Andrew , Beck Harald , Reyna-Hurtado Rafael , Lizarraga Leonidas , Keuroghlian Alexine , Sanderson Eric W. 
Published: December 2011

AbstractWe report a range-wide status assessment of a key Neotropical ecosystem architect, the white-lipped peccaryTayassu pecari, categorized as Near Threatened on the IUCN Red List, using published information and unpublished data from 41 scientists in 15 range countries. We estimate that the white-lipped peccary has been extirpated in 21% of its historical range over the last 100 years, with reduced abundance and a low to medium probability of long-term survival in another 48% of its current range. We found major range declines in Argentina, Paraguay, southern Brazil, Colombia, Venezuela, north-east Brazil, Mexico and Costa Rica. This species is particularly at risk in more xeric ecosystems, especially the caatinga, cerrado and pampas. Hunting and habitat destruction are the most severe threats, although there are also unexplained sudden die-offs suggestive of disease. We evaluate our results in light of this species’ important interspecific interactions and its role as an ecosystem architect. One of our recommendations is that conservation efforts should focus on landscape conservation of large, continuous and ecologically intact areas containing a mosaic of different habitat types.
Prescribing institutions: Explaining the evolution of physician dispensing
Authors: EGGLESTON KAREN 
Published: December 2011

Abstract:Health systems provide a rich field for testing hypotheses of institutional economics. The incentive structure of current healthcare delivery systems have deep historical and cultural roots, yet must cope with rapid technological change as well as market and government failures. This paper applies the economic approach of comparative and historical institutional analysis (Aoki, 2001; Greif, 2006) to health care systems by conceptualizing physician control over dispensing revenues as a social institution. The theory developed – emphasizing the interplay between cultural beliefs, interest groups, technological change, insurance expansion and government financing – offers a plausible explanation of reforms since the 1960s separating prescribing from dispensing in societies such as Japan, South Korea, Taiwan and China. Technological change and adoption of universal coverage trigger reforms by greatly increasing the social opportunity costs of physician over-prescribing and reshaping the political economy of forces impinging on the doctor–patient relationship.
Wie psychisch belastet fühlen sich Jugendliche mit selbstverletzendem Verhalten?
Authors: Rauber Rachel , Hefti Stephanie , In-Albon Tina , Schmid Marc 
Published: December 2011

In den letzten Jahren wurden zahlreiche Prävalenzstudien zum selbstverletzenden Verhalten bei Heranwachsenden in unterschiedlichen Ländern veröffentlicht. Aus der Schweiz liegen jedoch keine belastbaren Zahlen vor. Kritisch ist bei der Vielzahl der Studien anzumerken, dass sich diese oft auf ein „einfaches“ Feststellen der Prävalenz beschränken und kaum Hinweise für eine effektive Frühintervention geben. Im Rahmen einer epidemiologischen Fragebogenuntersuchung im Kanton Basel-Stadt wurden 447 Schüler (M = 14.95 Jahre, SD = 0.74, 52 % männlich) untersucht. Neben der Erfassung der Form und Art der Selbstverletzung wurde auch die psychische Belastung der Schüler erfasst. Es sollte überprüft werden, wie viele Selbstverletzer sich im Screening für psychische Störungen (SPS-J) als psychisch belastet beschreiben. 61 (13.6 %) Jugendliche gaben an, sich bereits mindestens einmal selbstverletzt zu haben. 29 (6.4 %) haben sich im letzten Monat selbst verletzt, 4 davon häufiger als viermal. Die Ergebnisse bestätigten die hohen Prävalenzraten für selbstverletzendes Verhalten. Interessant ist, dass Selbstverletzer im Schnitt zwar wesentlich höhere Werte im SPS-J erzielten, sich aber bei weitem nicht alle als psychisch auffällig beschrieben (18 von 61 selbstverletzenden Jugendlichen erzielten unauffällige Werte). Für eine effektivere Identifikation sollten daher Fragen zum selbstverletzenden Verhalten in psychopathologische Screeningfragebögen integriert werden, um diese Symptomatik adäquat abbilden zu können. Die Ergebnisse und die hohen Prävalenzen legen nahe, dass verschiedene Subgruppen von Selbstverletzern existieren, die passgenaue Hilfen für ihre Symptomatik benötigen.
The quasi 2 day wave and spatial‐temporal variability of the OH emission and ionosphere
Authors: Pedatella N. M. , Forbes J. M. 
Published: December 2011

The quasi 2 day wave (QTDW) during January 2006 is investigated using Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) observations of OH airglow and temperature in the mesosphere and lower thermosphere (MLT) and CHAMP in situ electron density observations at an altitude of ∼360 km. The zonal structure of the QTDW during early 2006 in the Southern Hemisphere MLT and low‐latitude ionosphere is dominated by westward propagating zonal wave number 3 (W3) and eastward propagating zonal wave number 2 (E2) components. However, the observed longitude variability is not fully described by the E2 and W3 components of the QTDW. The remaining longitude variability is attributed to the presence of nonmigrating tides and secondary waves generated by the nonlinear interaction of the QTDW with migrating tides. The nonmigrating tides are a combination of those that are generated in situ by QTDW‐tide nonlinear interactions and those of tropospheric origin that propagate upward into the MLT. The results presented demonstrate that nonmigrating tides and secondary waves are of considerable importance for determining the total longitude variability during periods of enhanced QTDW activity. The general similarity between the QTDW in OH airglow and temperature indicates that variations in atomic oxygen concentrations due to vertical winds during the QTDW are the primary driver of the QTDW in the OH airglow emission. However, there are some differences in the OH airglow and temperature that we consider to be connected to changes in eddy diffusion due to changes in gravity waves during the QTDW. Last, although similar zonal structure of the QTDW is observed in the ionosphere, the observed longitude variations are not well represented by the QTDW components, indicating that nonmigrating tides play a critical role in determining longitudinal variability in the ionosphere during the QTDW. The importance of nonmigrating tides in the ionosphere may be related to the relative efficiency of the QTDW and different nonmigrating tides in the generation of electric fields.