bluuebunny/crossref_metadata_2025 huggingface dataset:
Solvent‐assisted anionic ring opening polymerization of glycidol: Toward medium and high molecular weight hyperbranched polyglycerols
Authors: ul‐haq Muhammad Imran , Shenoi Rajesh A. , Brooks Donald E. , Kizhakkedathu Jayachandran N.
Published: March 2013

Hyperbranched polyglycerols (HPGs) are globular structures with a large number of functionalizable hydroxyl groups and have excellent in vitro and in vivo biocompatibility profiles comparable to polyethylene glycol. This work introduces a facile method for the synthesis of medium molecular weights (Mws) (50–300 kDa) HPGs, which has been difficult to synthesize with low polydispersity, with the assistance of solvents by ring opening polymerization. The influence of different solvents (1,4‐dioxane, tetrahydropyran (THP), ethylene glycol diethyl ether (EGDE) and decane), solvent to glycidol ratio, concentration of glycidol and the time of polymerization on Mw and polydispersity of HPGs has been studied. The Mw and polydispersity of HPGs are significantly affected by the nature of the polymerization phase (homogeneous or heterogeneous) and chemical structure of the solvent. The differences in the solvation of the potassium cations and change in the nucleophilicity of the alkoxide anion in various solvents may be responsible for the changes in Mw and PDI of the HPG. The Mw of the HPG decreases in the order 1,4‐dioxane > THP > EGDE >decane. The microstructure, solution and thermal properties of the HPG do not depend on the nature of solvent. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 2614–2621
Remaking a Bargain: The Political Logic of the Minimum Wage in the United States
Authors: Gitterman Daniel P.
Published: March 2013

This essay explores how political processes shaped the origins and development of the federal minimum wage in the United States, attempting to impose an order and logic on that process. It offers an analytically grounded narrative that abstracts from the historical details and interprets a broad sweep of outcomes between the New Deal and the present. Rather than identifying only the preferences of the ardent minimum wage supporters (and opponents), I identify those members of an enacting coalition (including the president) or veto players whose preferences had to be taken into account for a minimum wage bargain to be struck. For each episode, the analytical narrative identifies the coalition that made the minimum wage agreement—the members of Congress among whom a bargain was struck and codified into legislation, plus (usually) the president. The narrative also determines the nature of the compromise that enabled members of an enacting coalition to adopt an increase in the minimum wage. In each instance, policymakers were “heirs” before they were choosers: The heavy hand of later New Deal history shaped subsequent political choices.
Effects of Ar–N2–O2 Microwave Plasma on Poly‐L‐Lactic Acid Thin Films Designed for Tissue Engineering
Authors: Chichti Emna , Henrion Gerard , Cleymand Franck , Jamshidian Majid , Linder Michel , Arab‐Tehrany Elmira
Published: March 2013

Poly‐lactic acid (PLA) is the most used biopolymer in both biomedical and food packaging fields to replace petrochemical plastics. The surface properties of PLA thin films were studied before and after plasma treatment to enhance its wettability and its adhesive properties. Based on the experimental design, the most significant parameters of the plasma process were specified. The effect of the cold plasma treatment on the mechanical, topographic composition, thermal and barrier properties of the PLA was carried out using different Ar–N2–O2 gas mixture. Results show that the discharge gas can have a significant influence on the chemical composition and the wettability of the PLA surfaces. As the plasma processing is a surface treatment without affecting the bulk properties, it did not change the PLA properties.

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Time passes yet errors remain: Comments on the structure of N10‐formyltetrahydrofolate synthetase
Authors: Stec Boguslaw
Published: March 2013

PDB Code(s): 4IOJ, 4IOK, 4IOL, 4IOM
Rural Outmigration, Natural Capital, and Livelihoods in South Africa
Authors: Hunter Lori M. , Nawrotzki Raphael , Leyk Stefan , Maclaurin Galen J. , Twine Wayne , Collinson Mark , Erasmus Barend
Published: March 2013

Rural households across the globe engage in both migration and natural resource use as components of livelihood strategies designed to meet household needs. Yet, migration scholars have only recently begun to regularly integrate environmental factors into empirical modelling efforts. To examine the migration‐environment association in rural South Africa, we use vegetation measures derived from satellite imagery combined with detailed demographic data from over 9000 households at the Agincourt Health and Demographic Surveillance Site. Results reveal that household‐level temporary migration is associated with higher levels of local natural capital, although no such association exists for permanent migration. Further, more advantaged households exhibit a stronger association between migration‐environment, in‐line with the ‘environmental capital’ hypothesis, suggesting that natural resource availability can facilitate household income diversification. We argue that a focus on migration's environmental aspects is especially timely in the contemporary era of climate change and that natural capital availability and variability represent critical pieces of the empirical migration puzzle, especially regarding cyclical livelihood migration. Copyright © 2013 John Wiley & Sons, Ltd.
Optical properties of InGaN‐based LEDs investigated using high hydrostatic pressure dependent techniques
Authors: Crutchley B. G. , Marko I. P. , Pal J. , Migliorato M. A. , Sweeney S. J.
Published: March 2013

High pressure electroluminescence (EL) measurements were carried out on blue and green emitting InGaN‐based light emitting diodes (LEDs). The weak pressure coefficient of the peak emission energy of the LEDs is found to increase with increasing injection current. Such behaviour is consistent with an enhancement of the piezoelectric fields under high pressure which become increasingly screened at high currents. A subsequent increase in the quantum confined Stark effect (QCSE) is expected to cause a reduction of the light output power as pressure is applied at a fixed low current density (∼10 A cm−2). A similar proportional reduction of light output power as pressure is applied at a fixed high current density (260 A cm−2) suggests that there is a non‐radiative loss process in these devices which is relatively insensitive to pressure. Such behaviour is shown to be consistent with a defect‐related recombination process which increases with increasing injection.
Order–disorder processes in adamantine ternary ordered‐vacancy compounds
Authors: Manjón F. J. , Gomis O. , Vilaplana R. , Sans J. A. , Ortiz H. M.
Published: March 2013

Adamantine ternary ordered‐vacancy compounds (OVCs) of the AB2X4 family derive from the zincblende structure of binary AX compounds and share many properties with the chalcopyrite‐type ternary ABX2 compounds. AB2X4 mainly crystallize in the defect chalcopyrite (or thiogallate) structure but also in other vacancy‐ordered phases, like the defect stannite (DS, or defect famatinite) and the pseudocubic (PC) structures, where vacancies occupy a fixed Wyckoff site in an ordered and stoichiometric fashion. Order–disorder phase transitions have been studied in several adamantine OVCs at high temperatures and/or pressures, where OVCs undergo a phase transition to a disordered zincblende (DZ) structure on increasing temperature and to a disordered rocksalt (DR) structure on increasing pressure. It has been suggested that these order–disorder transitions should undergo via intermediate phases of partial disorder between the fully ordered phases and the fully disordered phases. In this work we study the different possible intermediate phases of partial disorder and discuss the possibility to find them with the help of vibrational spectroscopies, like Raman scattering or infrared measurements.
AlGaAs anode heterojunction PIN diodes
Authors: Boles T. , Brogle J. , Hoag D. , Carlson D.
Published: March 2013

This paper describes the development of a heterojunction AlGaAs/GaAs PIN diode as a revolutionary improvement as compared to the homojunction GaAs PIN diode commonly used in microwave systems for commercial and military applications. In a heterojunction device the injected carriers from the junction are confined by the bandgap discontinuity between the AlGaAs/GaAs layers. This confinement effectively reduces the series resistance within the I‐region of a PIN diode. Simulations of both single and double heterojunction PIN diodes predict a significant improvement in the return loss and insertion loss as compared to an equivalent GaAs PIN structure. In particular, the single heterojunction PIN diode, when simulated at a bias of 10 mA, indicates a factor of two reduction in high frequency insertion loss. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
High voltage GaN‐on‐silicon HEMT
Authors: Boles T. , Varmazis C. , Carlson D. , Palacios T. , Turner G. W. , Molnar R. J.
Published: March 2013

M/A‐COM Technology Solutions has continued in the joint development efforts sponsored by the Department of Energy with MIT main campus and MIT Lincoln Labs to develop GaN on silicon three terminal high voltage/high current HEMT switching devices. The first year developmental goals were for a three terminal structure that has a reverse breakdown characteristic of >1200 V and is capable of switching 10 amperes of current. An average three terminal breakdown of 1322 V was achieved on a single finger 250 µm GaN on silicon HEMT device utilizing a source connected field plate with a 4.5 µm drain region overlap. An individual device breakdown on a single finger 250 µm GaN on silicon HEMT device with a SCFP of >1630 V was measured at a current of 250 µA (1mA/mm) – One of the highest yet reported for GaN on silicon in the industry. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Kappa statistic for clustered dichotomous responses from physicians and patients
Authors: Kang Chaeryon , Qaqish Bahjat , Monaco Jane , Sheridan Stacey L. , Cai Jianwen
Published: March 2013

The bootstrap method for estimating the standard error of the kappa statistic in the presence of clustered data is evaluated. Such data arise, for example, in assessing agreement between physicians and their patients regarding their understanding of the physician–patient interaction and discussions. We propose a computationally efficient procedure for generating correlated dichotomous responses for physicians and assigned patients for simulation studies. The simulation result demonstrates that the proposed bootstrap method produces better estimate of the standard error and better coverage performance compared with the asymptotic standard error estimate that ignores dependence among patients within physicians with at least a moderately large number of clusters. We present an example of an application to a coronary heart disease prevention study. Copyright © 2013 John Wiley & Sons, Ltd.
Graphene: A Platform for Surface‐Enhanced Raman Spectroscopy
Authors: Xu Weigao , Mao Nannan , Zhang Jin
Published: March 2013

Surface‐enhanced Raman spectroscopy (SERS) imparts Raman spectroscopy with the capability of detecting analytes at the single‐molecule level, but the costs are also manifold, such as a loss of signal reproducibility. Despite remarkable steps having been taken, presently SERS still seems too young to shoulder analytical missions in various practical situations. By the virtue of its unique molecular structure and physical/chemical properties, the rise of graphene opens up a unique platform for SERS studies. In this review, the multi‐role of graphene played in SERS is overviewed, including as a Raman probe, as a substrate, as an additive, and as a building block for a flat surface for SERS. Apart from versatile improvements of SERS performance towards applications, graphene‐involved SERS studies are also expected to shed light on the fundamental mechanism of the SERS effect.
Brückenbauwerke mit stählernen Überbauten im Zuge der BAB A 9 zwischen Schkeuditzer Kreuz und Anschlußstelle Weißenfels
Authors: Fiedler E.
Published: March 2013

Die in dem Bereich des Autobahnabschnittes der BAB A 9 zwischen Schkeuditzer Kreuz und der Anschlußstelle Weißenfels gelegenen stählernen Autobahnbrücken wurden in beiden Bauabschnitten unterschiedlich ausgebildet. Bei dem ersten Bauabschnitt wurden die auf sekundären stählernen Längsträgern aufliegenden Stahlbetonplatten durch orthotrope Platten ersetzt, die auf die Obergurte der Hauptträger aufgeschweißt worden sind. Bei dem zweiten Bauabschnitt wurden wegen der größeren Querschnittsbreite der Autobahn neue stählerne Überbauten mit orthotroper Platte ausgeführt. Bei einer 180 m langen Talbrücke wurde ein einzelliger stählerner Hohlkasten in Verbundbauweise hergestellt.
Plastische Grenztragfähigkeit des Rechteckquerschnittes unter zweiachsiger Biegung und Normalkraft
Authors: Saal H. , Hornung U.
Published: March 2013

Für den Rechteckquerschnitt unter zweiachsiger Biegung und Normalkraft werden die Interaktionsbeziehungen für die Ermittlung der plastischen Grenztragfähigkeit hergeleitet. Die Interaktionsbeziehungen werden als Formeln angegeben, deren Gültigkeitsgrenzen ebenfalls durch Formeln beschrieben und graphisch dargestellt werden. Aus dieser Darstellung läßt sich eine Näherungsbetrachtung herleiten, mit der sich die Interaktion noch einfacher beschreiben läßt, die aber vor allem die Anwendung der Interaktionsbeziehungen auch in den Fällen rechtfertigt, in denen anstelle der vollplastischen Biegemomente nur das 1,25fache der elastischen Grenzmomente eingesetzt werden darf.
Tragendes Glas
Authors: Hess R.
Published: March 2013

Der Werkstoff Glas ist in den letzten Jahren zu einem sehr wichtigen und verbreiteten Baustoff geworden. Nachdem Glas bis dahin in erster Linie als transparentes raumabschließendes Element verwendet wird, erfolgt in jüngster Zeit vermehrt der Einsatz als eigentliches Tragelement. In einer Einführung werden die verschiedenen Glassorten sowie Spezialgläser näher beschrieben. Diese Einführung ist sowohl für den Architekten als auch für den Bauingenieur interessant. Es wird auch kurz auf die Bemessung von Glas eingegangen, indem die gegenwärtige Technik aufgezeigt wird und Hinweise auf neuere Methoden gegeben werden. Ferner wird auf den Entwurf von europäischen Normen eingegangen. Nach einer Umschreibung des Begriffs tragendes Glas anhand des Eurocodes 1 werden einige Beispiele von Bauten, wo tragendes Glas Verwendung findet, beschrieben. Es sind Objekte, an denen der Autor selbst mitgewirkt hat.
Beulen biegebeanspruchter, langer Kreiszylinderschalen aus Stahl ‐ Versuch, Theorie und Bemessung
Authors: Speicher G. , Saal H.
Published: March 2013

Als Ergebnis experimenteller und rechnerischer Untersuchungen über die Beullasten von Kreiszylinderschalen aus Baustahl, die unter Bedingungen der Stahlbauindustrie gefertigt waren, wird vorgeschlagen, bei dem Beulsicherheitsnachweis nach DIN 18800‐4 für biegebeanspruchte Kreiszylinderschalen aus Baustählen den Beiwert Cx gleich Eins zu setzen.
Beulwiderstand axialgedrückter Metallkreiszylinderschalen mit unversteifter Mantelöffnung
Authors: Velickov D. , Schmidt H.
Published: March 2013

Die in den einschlägigen nationalen und internationalen Regelwerken angebotenen Nachweiskonzepte für die Beulsicherheit axialbelasteter Metallkreiszylinder mit seitlicher Mantelöffnung sind nach Wissen der Verfasser nicht streng statistisch abgesichert. In diesem Beitrag werden die im Entwurf zur DASt‐Ri 017 für diesen Beulfall angegebene Nachweisformel und ein alternatives Berechnungsmodell anhand von recherchierten Versuchsergebnissen mit statistischen Hilfsmitteln kalibriert. Ein Vergleich der Ergebnisse zeigt, daß das alternative Berechnungsmodell durch Berücksichtigung der Öffnungslänge für den hier untersuchten Parameterbereich teilweise zutreffendere Schätzwerte für den Beulwiderstand liefert.
Geometrisch und physikalisch nichtlineare Analyse von Druckbehältern
Authors: Sanal Z.
Published: March 2013

Anhand zweier Beispiele aus dem Druckbehälterbau wird gezeigt, daß mit Hilfe geometrisch und physikalisch nichtlinearer Finite‐Element‐Analysen die Bauteiltragfähigkeit sehr wirklichkeitsnahe simuliert werden kann und so wirtschaftliche und zugleich sichere Auslegungen möglich sind. Die mitunter extreme Konservativität der einfachen Bemessungsformeln in Regelwerken wird am Beispiel des Beuldruckes eines unrunden Rohres demonstriert. Ferner wird für einen kaltgereckten Behälter gezeigt, daß eine physikalisch nichtlineare aber geometrisch lineare Analyse vollkommen falsche Ergebnisse liefern kann. Es wird erörtert, daß eine befriedigende Analyse der Tragfähigkeit von Druckbehältern mit geometrischen Imperfektionen bzw. im überelastischen Bereich nur mit Hilfe einer vollständig nichtlinearen FEA gelingt. Die erzielte gute Übereinstimmung zwischen Theorie und Experiment rechtfertigt den Einsatz moderner und zuverlässiger FE‐Analysewerkzeuge als Ergänzung zum und ggf. auch Einsatz für den Versuchsweg.
Zum Einfluß teiltragfähiger, verformbarer Verbundanschlüsse auf das Tragverhalten von Verbundträgern
Authors: Bode H. , Kronenberger H.‐J.
Published: March 2013

Verbindungen bzw. Anschlüsse haben die Kräfte und Momente zwischen den einzelnen Bauteilen mit einer ausreichenden Sicherheit zu übertragen. Ihr Tragverhalten beeinflußt die Verteilung der Schnittgrößen innerhalb des Tragwerks. Im vorliegenden Beitrag wird das Momenten‐Verdrehungsverhalten von Verbundanschlüssen anhand von Versuchen beschrieben, und ihr Einfluß auf das Tragverhalten von Verbund‐Durchlaufträgern mit nachgiebigen, teiltragfähigen Verbindungen wird aufgezeigt. Vorschläge zur rechnerischen Bestimmung der kennzeichnenden Anschlußeigenschaften werden vorgestellt, mit Versuchsergebnissen verglichen und diskutiert.
Zur Bemessung von Verbundstützen nach DIN 18800 Teil 5
Authors: Lindner J. , Bergmann R.
Published: March 2013

Der Entwurf zur DIN 18800 Teil 5 führt für Verbundkonstruktionen und damit auch für Verbundstützen die Bemessung mit Teilsicherheitsbeiwerten ein. Weiterhin wird das vereinfachte Bemessungsverfahren für Verbundstützen auf eine Bemessung mit geometrischen Ersatzimperfektionen umgestellt. Die wesentlichen Änderungen gegenüber der bisherigen Verbundstützennorm DIN 18806 werden vorgestellt und die Hintergründe der geänderten Bemessung erläutert.
Die neue Autobahnbrücke über die Elbe bei Dresden. Planung, Entwurf und Vergabe
Authors: Reintjes K.‐H. , Schmackpfeffer H. , Volke E. , Wange G.
Published: March 2013

Der folgende Aufsatz ist der erste von zwei Beiträgen über den Bau der neuen Elbebrücke im Zuge der A4 in Dresden. Der erste Teil beinhaltet die Planung, den Entwurf sowie Ausschreibung und Vergabe. Die Elbebrücke ist eine der größten Brücken des Verkehrsprojektes Nr. 15 der Deutschen Einheit. Die Länge der Brücke beträgt 500 m, die Hauptspannweite beträgt 130 m. Die Brücke wird in Verbundbauweise als Hohlkastendurchlaufträger mit veränderlicher Bauhöhe ausgeführt. Die Brücke ist seit Juni 1995 im Bau, Verkehrsübergabe wird im Dezember 1998 sein.
Fortschritte im Eisenbahn‐Stahlbrückenbau Europas
Authors: Tschumi M. , Grüter R. , Ramondenc P.
Published: March 2013

Der nachfolgende Aufsatz entstand im Rahmen des Unterausschusses Brückenbau des Internationalen Eisenbahnverbandes (UIC). Die Chefs Brückenbau der verschiedenen Bahnen Europas treffen sich jährlich zwei Mal zu einer Sitzung, um Entwürfe für Normen (EUROCODES) oder UIC‐Merkblätter zu genehmigen. Der UIC‐Unterausschuß Brückenbau hat infolge der Reorganisation UIC seine institutionalisierte Funktion vorübergehend verloren. Die Chefs Brückenbau pflegen weiterhin einen intensiven Gedankenaustausch, um den Eisenbrückenbau wirtschaftlich weiter zu entwickeln, die europäische Normung in ihrem Bereich zu fördern und um kostengünstige Instandhaltungskonzepte zu finden.
Brücken im Eisenbahnkorridor Berlin ‐ Prag ‐ Wien
Authors: Krása D.
Published: March 2013

Dieser Beitrag befaßt sich aus der Sicht einer Planungs‐ und Beratungsfirma mit dem Brückenbau und der damit im Zusammenhang stehenden Modernisierung des auf dem Gebiet der Tschechischen Republik liegenden Teils des Eisenbahnkorridors Berlin‐Prag‐Wien. Der Brückenbau ist in das gesamte Investitionsvorhaben "Ausbau des Korridors" eingegliedert. Es werden Gesichtpunkte zur Entscheidungsfindung einzelner Brückenobjekte dargelegt, d. h. reparieren, sanieren oder insgesamt umbauen. Beschrieben werden die am meisten angewandten Sanierungsmethoden und die am häufigsten vorgesehenen Konstruktionen für den Umbau solcher Objekte. Die größte Aufmerksamkeit wird Brücken in Stahl‐ oder Verbundbauweise gewidmet.
Das Dach der Leichtathletikhalle in Halle/Saale ‐ eine weitgespannte Rohrkonstruktion
Authors: Beinlich B. , Kasimir R. , Langrock St. , Müglitz J. , Tröger A.
Published: March 2013

Es wird über die Fertigung, den Transport und die Montage einer räumlichen Tragkonstruktion aus Rohren berichtet. Besondere Anforderungen erwuchsen aus der Größe und Masse der Bauteile, der Gestaltung der Rohrknoten und dem vorgegebenen Zeitrahmen. Besonders die Aspekte der Schweiß‐ und Schneidtechnik, der Werkstatt‐ und Baustellenfertigung werden detailliert beschrieben.
Die Nesenbachtalbrücke ‐ Vom Wettbewerb bis zur Ausschreibung
Authors: Bornscheuer B.‐F. , Eisele St.
Published: March 2013

Verbundkonstruktionen bewähren sich auch im Brückenbau in immer besserer Art und Weise. Die im folgenden vorgestellte Brücke besteht aus einem geschweißten Hohlkasten aus S 355 J5G3 und hochfestem Feinkornbaustahl S 690 QL1, der in Deutschland für diese Anwendungen zum ersten Mal verwendet wird. Der Hohlkasten ist mit Rohrprofilen verbunden, die im Abstand von ca. 4,0 m Querträger unterstützen. Diese Querträger wiederum unterstützen selbsttragende Fertigteilplatten mit einer Dicke von 12 cm, die mit Aufbeton zu einem Gesamtquerschnitt von 40 cm Dicke ergänzt werden. Die Verbundwirkung wird durch eine Bügelbewehrung sichergestellt. Bei dieser innovativen Bauweise kann sowohl auf ein Lehrgerüst als auch auf Schalung verzichtet werden.
Tragverhalten des Dachverband‐Rahmen‐Wände‐Systems typischer Hallen
Authors: Rosman R.
Published: March 2013

Es werden das Tragverhalten des räumlichen Dachverband‐Rahmen‐Wände‐Systems eines geläufigen Hallentyps bei Wind‐ und Erdbebeneinwirkungen in der Querrichtung der Halle analysiert und einfache Formeln der Antwortgrößen hergeleitet. Anhand einer Tabelle dimensionsloser Beiwerte der maßgebenden Schnittkräfte und Druchbiegungen kann die Entwurfsarbeit derart vereinfacht werden, daß sie kaum schwieriger ist als die Untersuchung eines einfachen Balkens oder von Rahmen bei im voraus bekannter Last. Die Ergebnisse des an einem stetigen mechanischen Modell aufbauenden Verfahrens werden mit jenen eines an einem diskteten Modell gründenden verglichen. Ein Beispiel behandelt vier Varianten zahlenmäßig, womit das Tragverhalten und der Einfluß der Systemparameter auf die maßgebenden Antwortgrößen illustriert wird. Ferner wird auf Anwendungsmöglichkeiten der entwickelten Verfahren in anderen Bereichen des konstruktiven Ingenieurbaus hingewiesen.
Zum Nachweis ausgesteifter biegedrillknickgefährdeter Träger
Authors: Friemann H. , Stroetmann R.
Published: March 2013

Beim Nachweis ausreichender Tragsicherheit biegedrillknickgefährdeter Träger wird häufig die stabilisierende Wirkung angrenzender Bauteile in Rechnung gestellt. Die Aufnahme der Stabilisierungskräfte muß dabei gewährleistet sein. Im folgenden Beitrag wird das Tragverhalten des Systems "Träger ‐ Aussteifung" im Hinblick auf die Stabilität und die Beanspruchung nach Theorie II. Ordnung behandelt. Neben dem Einfluß unterschiedlicher Schnittkraftverläufe, Imperfektionsannahmen und Querschnittsausbildungen werden verschiedene Aussteifungsmaßnahmen und deren Wechselwirkungen untersucht. Auf der Grundlage der Energiemethode wird eine Näherungslösung für das Verzweigungsproblem und das Spannungsproblem Theorie II. Ordnung hergeleitet. Letztere liefert die Beanspruchungen sowohl des biegedrillknickgefährdeten Trägers als auch der aussteifenden Bauteile. Die Anwendung wird an einem Beispiel gezeigt.
Anwendung der Mehrkörperdynamik auf Probleme des Stahlbaus
Authors: Neuenhaus D.
Published: March 2013

Das Ziel dieses Beitrages ist es, die Einsetzbarkeit der Methode der Mehrkörperdynamik für die Formulierung von Grenzzuständen bei Stahlkonstruktionen aufzuzeigen, Die Methode der Mehrkörperdynamik dient der Erfassung kinematischer Vorgänge, bei denen sich mit der Zeit die Geometrie oder die Systeme stark verändern und ist ursprünglich im Maschinenbaubereich beheimatet. Im ersten Teil dieser Trilogie, wird die Methode der Mehrkörperdynamik in der Schreibweise von Wittenburg vorgestellt, die Grundlage für die Entwicklung des Mehrkörperprogrammsystems MEPHISTO ist. Der folgenden beiden Teile beschäftigen sich mit neuartigen Mehrkörper‐Ersatzmodellen für die Abbildung plastischer Gelenke, Seile und Kontaktzonen.
A seismic geotraverse across the Iberian Variscides: Orogenic shortening, collisional magmatism, and orocline development
Authors: Simancas J. F. , Ayarza P. , Azor A. , Carbonell R. , Martínez Poyatos D. , Pérez‐Estaún A. , González Lodeiro F.
Published: March 2013

A crustal geotraverse through the Iberian Variscides is presented by integrating the available geological and seismic profiling data. Different modes of orogenic shortening are identified, with varying degrees of coupling between upper and lower crust. In northern and southern regions of the geotraverse, a decoupling in the middle crust permits the lower crust to subduct/underthrust, thus compensating for strong upper crustal shortening. This behavior does not result in great crustal thickening, except in sectors of crustal underthrusting. In southern Central Iberia, moderate upper crustal shortening is due to a mechanically strong lower crust impeded to subduct/underthrust. In this region, shortening is partitioned between upper and lower crust, deformation being distributed in the upper crust while localized at major fault zones in the lower crust. Finally, the central region of the geotraverse (northern Central Iberia) shows a coupled crustal deformation, having given way to the largest orogenic thickening in the Iberian Variscides. The thermal maturity of this much thickened crust originated voluminous crustal melting, and concomitant normal‐fault detachments developed, while shortening dominated in other regions. Theoretical models suggest that compressive stresses may prevail in the lower crust beneath the extending upper crust, thus explaining the efficient syncollisional exhumation in this part of the orogen. A particular feature of the Iberian Variscan geotraverse is the great importance of out‐of‐section mass movements, mainly left‐lateral shear zones concentrated in two suture boundaries, which displaced to the NW (present coordinates) central and northern Iberia with respect to southern Iberia.
A Framework for Using iPads to Build Early Literacy Skills
Authors: Northrop Laura , Killeen Erin
Published: March 2013

The quick adoption of iPads into the classroom, coupled with the many apps targeting early literacy skills, offers a new way to build early literacy skills with emergent and beginning readers. However, young children may be more proficient with the technology than with the literacy concepts, and may not be maximizing learning, or even learning at all, when using apps. This article uses the gradual release of responsibility framework as a way to integrate iPads into early literacy classrooms. The sequence of direct instruction with modeling and teacher think alouds, followed by guided and independent practice, offers teachers a way to differentiate instruction and ensure that all students are effectively working on literacy concepts targeted to their individual instructional level.
How to perform ultrasound in labor: assessment of fetal occiput position
Authors: Youssef A. , Ghi T. , Pilu G.
Published: March 2013

How To…

Practical advice on imaging‐based techniques and investigations with accompanying slides and videoclips online
Effectiveness of search dogs compared with human observers in locating bat carcasses at wind‐turbine sites: A blinded randomized trial
Authors: Mathews Fiona , Swindells Michael , Goodhead Rhys , August Thomas A. , Hardman Philippa , Linton Danielle M. , Hosken David J.
Published: March 2013

With the expansion of wind‐energy generation, there is a growing need to develop accurate and efficient methods to detect bat casualties resulting from turbine collision and barotrauma. We conducted a formal blinded trial comparing the abilities of search dogs and human observers to locate bat carcasses. Dogs located 73% (46/63) of bats, whereas humans found 20% (12/60). We therefore recommend search dogs as an effective means of monitoring bat fatalities, particularly when a high degree of search accuracy is important. This includes surveys for rare species, or cases where searches are limited in extent or duration, because the application of correction factors is problematic where very few or no casualties are found. The dogs averaged 40 min to complete a survey, which was <25% of the time taken by humans. At large sites, the high initial set‐up costs for search dogs can therefore be offset by the increased number of surveys that can be conducted within a given time. However, care must be taken with the selection and training of the dogs and handlers to produce consistent results. To allow fatality rates to be estimated from the number of casualties located, it is essential that assessments of the accuracy of the dog–handler team are made at each site. © 2013 The Wildlife Society.
Synthesis and Structure of Ionic Liquids Containing the ­[Al(OC6H4CN)4]– Anion
Authors: Lund Henrik , Harloff Jörg , Schulz Axel , Villinger Alexander
Published: March 2013

The synthesis, structure, and physical properties of ionic liquids (IL) bearing the novel [Al(O–C6H4–CN)4]– ion as counterion to the commonly used [NR4]+, [PR4]+ and imidazolium ions are reported. Both the influence of the alkyl chain length as well as the functionalization with cyano groups is studied. These ILs are easily obtained by reaction of Ag[Al(O–C6H4–CN)4] with the corresponding ammonium, phosphonium, and imidazolium halides. The stability towards electrophilic cations was investigated. All prepared salts have a window for the liquid phase of ca. 200 °C and are thermally stable up to 450 °C. The solid‐state structures reveal only weak cation···anion and anion···anion interactions in accord with the observed low melting points (glass transition points).
Outcome of Patients with Aggressive Pseudomyxoma Peritonei Treated by Cytoreductive Surgery and Intraperitoneal Chemotherapy
Authors: Arjona‐Sanchez Alvaro , Muñoz‐Casares Francisco Cristobal , Casado‐Adam Angela , Sánchez‐Hidalgo Juan Manuel , Ayllon Teran Maria Dolores , Orti‐Rodriguez Rafael , Padial‐Aguado Ana Cristina , Medina‐Fernández Javier , Ortega‐Salas Rosa , Pulido‐Cortijo Gema , Gómez‐España Auxiliadora , Rufián‐Peña Sebastián
Published: March 2013

Background

Pseudomyxoma peritonei (PMP) is a rare disease with an incidence rate of approximately 1 per million a year. During the past few years, there has been a survival benefit for these patients treated by complete cytoreduction and perioperative chemotherapy. Better survival rates were found in the adenomucinosis group than the carcinomatosis group. The purpose of our study was to analyze the outcome and the prognosis factors of only high‐grade PMP.

Methods

We selected 38 patients from a prospective database of 59 with high‐grade PMP from appendiceal origin who were treated by cytoreduction surgery and HIPEC at the Hospital University Reina Sofia (Cordoba, Spain) between 1998 and July 2012. Clinical, surgical, analytical, radiological, and histological data were obtained prospectively. Survival curves were calculated using the Kaplan–Meier method, a univariate analysis was performed and the log rank‐test was used to analyze the effects of several clinical and pathologic factors on overall survival (OS) and disease‐free survival (DFS).

Results

Median follow‐up time was 32 months (range, 2–170). Median age at diagnosis was 57 years (range, 32–77). In 89.5 % of patients, optimal cytoreduction CC‐0 (57.9 %) and CC‐1 (31.6 %) was achieved. In the remaining 10.5 %, cytoreduction was classified as CC‐2. The median PCI score was 21 (range, 4–38). Morbidity complications ≥Grade 3 in the CTCAE v 3.0 classification was 18.4 %. One patient died 45 days postsurgery. Median OS at the end of follow‐up was 36 months (range, 9–83); overall 5‐year survival rate was 58.7 %. In the univariate analysis for OS, significant values were obtained for lymph‐node involvement and suboptimal cytoreduction. The 5‐year OS was 64.5 % when an optimal cytoreduction was achieved. Median DFS was 36 months (17–54); 3‐year DFS rate was 49.1 %. Neoadjuvant therapy did not affect the survival of these patients; there was no difference in the 5‐year OS (43 % vs. 75 %, p = 0.068).

Conclusions

In aggressive PMP, cytoreduction with peritonectomy procedure plus HIPEC is a safe procedure that suggests an improvement to the survival rates. Because optimal cytoreduction is a primary prognostic factor for survival rates, this procedure would have to be performed in an experienced center with a low morbidity. Neoadjuvant chemotherapy has not demonstrated benefits in these patients and further research will be required.
HDAC inhibitors dysregulate neural stem cell activity in the postnatal mouse brain
Authors: Foti Stacey Beth , Chou Athena , Moll Andrew D. , Roskams A. Jane
Published: March 2013

The mammalian central nervous system (CNS) undergoes significant expansion postnatally, producing astrocytes, oligodendrocytes and inhibitory neurons to modulate the activity of neural circuits. This is coincident in humans with the emergence of pediatric epilepsy, a condition commonly treated with valproate/valproic acid (VPA), a potent inhibitor of histone deacetylases (HDACs). The sequential activity of specific HDACs, however, may be essential for the differentiation of distinct subpopulations of neurons and glia. Here, we show that different subsets of CNS neural stem cells (NSCs) and progenitors switch expression of HDAC1 and HDAC2 as they commit to a neurogenic lineage in the subventricular zone (SVZ) and dentate gyrus (DG). The administration of VPA for only one week from P7–P14, combined with sequential injections of thymidine analogs reveals that VPA stimulates a significant and differential decrease in the production and differentiation of progeny of NSCs in the DG, rostral migratory stream (RMS), and olfactory bulb (OB). Cross‐fostering VPA‐treated mice revealed, however, that a postnatal failure to thrive induced by VPA treatment had a greater effect on DG neurogenesis than VPA action directly. By one month after VPA, OB interneuron genesis was significantly and differentially reduced in both periglomerular and granule neurons. Using neurosphere assays to test if VPA directly regulates NSC activity, we found that short term treatment with VPA in vivo reduced neurosphere numbers and size, a phenotype that was also obtained in neurospheres from control mice treated with VPA and an alternative HDAC inhibitor, Trichostatin A (TSA) at 0 and 3 days in vitro (DIV). Collectively, these data show that clinically used HDAC inhibitors like VPA and TSA can perturb postnatal neurogenesis; and their use should be carefully considered, especially in individuals whose brains are actively undergoing key postnatal time windows of development.
Explaining Hamas's Changing Electoral Strategy, 1996–2006
Authors: Løvlie Frode
Published: March 2013

Hamas, the most influential Islamist party in the occupied Palestinian territories, replaced its strategy of electoral boycott in 1996 with participation in 2006 – a change that is not explained in the literature. Assisted by theories of party change, the article seeks to fill this gap. The article demonstrates that the move from boycott to participation can largely be attributed to a change of dominant coalition. In line with the theoretical assumptions, environmental challenges and shocks altered the power–balance within Hamas, robbing the coalition dominating at the time of the boycott of its power and allowing a new faction to obtain dominance. This new dominant faction saw political participation as a legitimate avenue to pursue Hamas's cause, and its rise to power secured the change of strategy and participation in the 2006 elections.
Ontogeny of the brain in oval squid Sepioteuthis lessoniana (Cephalopoda: Loliginidae) during the post-hatching phase
Authors: Kobayashi Shiori , Takayama Chitoshi , Ikeda Yuzuru
Published: March 2013

Among invertebrates, cephalopods have one of the most well-organized nervous systems. However, with respect to the ontogeny of the nervous system, the post-embryonic development of the cephalopod brain has only been documented for a few species. Here, we investigated the development of the brain of captive oval squid Sepioteuthis lessoniana during the post-hatching phase. The central part of the brain of the oval squid is divided into four main regions, namely, the supraoesophageal, anterior suboesophageal, middle suboesophageal, and posterior suboesophageal masses, each consisting of several lobes. At various ages in juvenile squid, the total volume of the central part of the brain (except the optic lobe) is significantly correlated with its body size, indicated by mantle length and wet body weight. The vertical lobe, superior frontal lobe, and anterior subesophageal mass drastically increase in relative volume as the squid grows. In contrast, the middle suboesophageal mass and posterior suboesophageal mass do not increase in volume with increasing squid age and body size. The effects of these results have been discussed in relation to the onset of squid behaviours during post-hatching.
Reproductive traits of horned octopusEledone cirrhosain Atlantic Iberian waters
Authors: Regueira Marcos , González Angel F. , Guerra Ángel , Soares Amadeu
Published: March 2013

Length–weight relationships, sex-ratio, maturity patterns, size at first maturity, reproductive outputs, fecundity and spawning period of horned octopusEledone cirrhosain north-west Iberian coast are presented for the first time. Samples were collected between February 2009 and July 2011 in four fishing ports along the north-west Iberian coast: Burela in north Galician waters (NGW), Ribeira or Bueu in western Galician waters (WGW), and Aveiro in western Portuguese waters (WPW). A total of 4127 individuals (1042 males, 3079 females and six undetermined) were sampled. Individuals ranged from 45 to 191 mm dorsal mantle length (ML) and 15–1159 g body weight (BW). The overall sex-ratio was biased towards females, accounting for 74.71% of whole sample. Main spawning season of this species in north-western Iberian waters extends from May to June. Size at first maturity (ML50%) of males was 108.9 mm in NGW, 99.25 mm in WGW, and 91.4 mm in WPW, whereas ML50%for females were 134.5 mm, 121.4 mm and 100.8 mm, respectively. Potential fecundity was 2452.88 ± 36.4 oocytes per ovary (N = 697). Mean oocyte length was 3.89 ± 0.025 mm (N = 697). The average number of fully developed spermatophores in mature males was 86.55 ± 1.9 (N = 223) with a mean length of 44.97 ± 0.29 mm (N = 224). Potential fecundity in females was significantly (P < 0.05) correlated with ML and BW. Results obtained suggest that energy for gonad growth comes from the diet rather than endogenous reserves.
Beyond the Front Line: China's rivalry with Japan in the English-language press over the Jinan Incident, 1928
Authors: WEI SHUGE
Published: March 2013

This paper examines how China and Japan fought for supremacy in China's treaty-port English-language press during the Jinan Incident of 1928. It argues that China's defeat in this media battle was a result of the long-term, unsettled political conditions the country was experiencing. The constant changes of government thwarted China's official and non-official efforts to establish a national news network. The threat from the northern warlords and China's intricate relations with the imperialist powers deterred the Nanjing regime from formulating decisive foreign propaganda policies. In contrast, Japan, with a strong news network in China, quickly installed its version of the event in the media. Its response was fast, consistent, and intensive. Japan also took advantage of the Nanjing Incident to justify its actions in Jinan. Press opinion in the treaty ports towards the Jinan Incident was split, with the British press supporting the Japanese and American papers favouring China's case. However, Japanese accounts, with the endorsement of the British treaty-port papers, still dominated the reports inThe Timesof London and influenced the views of theManchester GuardianandThe New York Times.
The Comparative Method of language acquisition research: a Mayan case study
Authors: PYE CLIFTON , PFEILER BARBARA
Published: March 2013

This article demonstrates how the Comparative Method can be applied to cross-linguistic research on language acquisition. The Comparative Method provides a systematic procedure for organizing and interpreting acquisition data from different languages. The Comparative Method controls for cross-linguistic differences at all levels of the grammar and is especially useful in drawing attention to variation in contexts of use across languages. This article uses the Comparative Method to analyze the acquisition of verb suffixes in two Mayan languages: K'iche' and Yucatec. Mayan status suffixes simultaneously mark distinctions in verb transitivity, verb class, mood, and clause position. Two-year-old children acquiring K'iche' and Yucatec Maya accurately produce the status suffixes on verbs, in marked distinction to the verbal prefixes for aspect and agreement. We find evidence that the contexts of use for the suffixes differentially promote the children's production of cognate status suffixes in K'iche' and Yucatec.
A meta-analysis of effectiveness studies on computer technology-supported language learning
Authors: Grgurović Maja , Chapelle Carol A. , Shelley Mack C.
Published: March 2013

With the aim of summarizing years of research comparing pedagogies for second/foreign language teaching supported with computer technology and pedagogy not-supported by computer technology, a meta-analysis was conducted of empirical research investigating language outcomes. Thirty-seven studies yielding 52 effect sizes were included, following a search of literature from 1970 to 2006 and screening of studies based on stated criteria. The differences in research designs required subdivision of studies, but overall results favored the technology-supported pedagogy, with a small, but positive and statistically significant effect size. Second/foreign language instruction supported by computer technology was found to be at least as effective as instruction without technology, and in studies using rigorous research designs the CALL groups outperformed the non-CALL groups. The analyses of instructional conditions, characteristics of participants, and conditions of the research design did not provide reliable results because of the small number of effect sizes representing each group. The meta-analysis results provide an empirically-based response to the questions of whether or not technology-supported pedagogies enhance language learning, and the process of conducting the meta-analysis pointed to areas in research methodology that would benefit from attention in future research.
Impact of the Christchurch Earthquakes on Hospital Staff
Authors: Tovaranonte Pleayo , Cawood Tom J.
Published: March 2013

Introduction

On September 4, 2010 a major earthquake caused widespread damage, but no loss of life, to Christchurch city and surrounding areas. There were numerous aftershocks, including on February 22, 2011 which, in contrast, caused substantial loss of life and major damage to the city. The research aim was to assess how these two earthquakes affected the staff in the General Medicine Department at Christchurch Hospital.

Problem

To date there have been no published data assessing the impact of this type of natural disaster on hospital staff in Australasia.

Methods

A questionnaire that examined seven domains (demographics, personal impact, psychological impact, emotional impact, impact on care for patients, work impact, and coping strategies) was handed out to General Medicine staff and students nine days after the September 2010 earthquake and 14 days after the February 2011 earthquake.

Results

Response rates were ≥ 99%. Sixty percent of responders were <30 years of age, and approximately 60% were female. Families of eight percent and 35% had to move to another place due to the September and February earthquakes, respectively. A fifth to a third of people had to find an alternative route of transport to get to work but only eight percent to 18% took time off work. Financial impact was more severe following the February earthquake, with 46% reporting damage of >NZ $1,000, compared with 15% following the September earthquake (P < .001). Significantly more people felt upset about the situation following the February earthquake than the September earthquake (42% vs 69%, P < .001). Almost a quarter thought that quality of patient care was affected in some way following the September earthquake but this rose to 53% after the February earthquake (12/53 vs 45/85, P < .001). Half believed that discharges were delayed following the September earthquake but this dropped significantly to 15% following the February earthquake (27/53 vs 13/62, P < .001).

Conclusion

This survey provides a measure of the result of two major but contrasting Christchurch earthquakes upon General Medicine hospital staff. The effect was widespread with minor financial impact during the first but much more during the second earthquake. Moderate psychological impact was experienced in both earthquakes. This data may be useful to help prepare plans for future natural disasters.

TovaranonteP, CawoodTJ. Impact of the Christchurch earthquakes on hospital staff. Prehosp Disaster Med. 2013;28(3):1-6.
massMobile: towards a flexible framework for large-scale participatory collaborations in live performances
Authors: Weitzner Nathan , Freeman Jason , Chen Yan-Ling , Garrett Stephen
Published: March 2013

massMobile is a client-server system for large audience participation in live performances using mobile devices. It allows for rapid development, deployment and iterative experimentation in participatory design, while minimising technical and logistical overhead. It was designed to flexibly adapt to a variety of participatory performance needs and to a variety of performance venues. It allows for real-time bi-directional communication between performers and audiences utilising existing 3G, 4G or WiFi networks. Audience members access massMobile through a smartphone-optimised web application utilising common web standards. An offsite server passes data between the audience and the performer(s) and stores the data for later analysis. In this paper, we discuss the goals, design and implementation of the framework, and we describe several projects realised with massMobile.