Search

Copyright of Bautechnik is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Beton- Und Stahlbetonbau is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Bautechnik is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Bautechnik is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Complex statistical models such as scalar-on-image regression often require strong assumptions to overcome the issue of nonidentifiability. While in theory, it is well understood that model assumptions can strongly influence the results, this seems to be underappreciated, or played down, in practice. This article gives a systematic overview of the main approaches for scalar-on-image regression with a special focus on their assumptions. We categorize the assumptions and develop measures to quantify the degree to which they are met. The impact of model assumptions and the practical usage of the proposed measures are illustrated in a simulation study and in an application to neuroimaging data. The results show that different assumptions indeed lead to quite different estimates with similar predictive ability, raising the question of their interpretability. We give recommendations for making modeling and interpretation decisions in practice based on the new measures and simulations using hypothetic coefficient images and the observed data. [ABSTRACT FROM AUTHOR]

Der vorliegende Beitrag befasst sich mit der konzentrierten Tangentialkrafteinleitung von Stahlbauteilen in Betonkonstruktionen mittels Zahnleistenverbindungen. Verbindungen mit Zahnleisten bestehen aus einem dicken Stahlblech mit Stahlzähnen, welche sich über Druckkräfte im Beton abstützen. Zur Klärung der Traglast und des Last-Verformungsverhaltens wurden experimentelle und numerische Untersuchungen durchgeführt. Als erster Schritt wurden experimentelle Untersuchungen zur Tragfähigkeit der Verzahnung zwischen Beton und Stahl unter verschiedenen Druckfeldwinkeln durchgeführt. Der Beton im Verbindungsbereich zeigte eine vergleichbare Tragfähigkeit wie ungestörter Beton. Weiterhin wurde ein Bauteilversuch mit Zahnleistenverbindung entworfen und durchgeführt. Damit konnten die Traglast und die Last-Verformungseigenschaften für druckgestützte innenliegende Zahnleistenverbindungen in einer realitätsnahen Einbausituation untersucht werden. Mit einem neu entwickelten numerischen Modell ließen sich die Versuchsergebnisse interpretieren. Anhand der gewonnenen Erkenntnisse wurde das Bemessungskonzept ergänzt. High capacity saw tooth connectors - experimental testing and numerical studies. The presented paper describes the transfer of concentrated loads from structural steelwork into concrete structures using saw tooth connectors. Saw tooth connectors consists of a thick steel plate with steel teeth which transfer forces into the surrounding concrete via compressive action. Experimental and numerical investigations have been undertaken in order to clarify the ultimate load and the load deflection behaviour. Firstly, experimental studies on the load carrying capacity of the steel teeth/concrete interface have been conducted. The compressive forces onto the teeth have been applied at varying angles of action. The concrete at the connection has a similar load capacity as an undisturbed concrete section. Secondly, a test of a complete connection within a concrete slab has been designed. The saw tooth connector used, was a two sided connector in a situation with compressive reaction. With this, load capacity and load deflection tests in a real live situation have been undertaken. In combination with the also developed numerical model, the tests were interpreted. The investigation concluded in an addition to the structural design concept. [ABSTRACT FROM AUTHOR]

In den vergangenen Jahrzehnten wurden zahlreiche Untersuchungen zum Trag- und Verbundverhalten von faserverstärkten Holzquerschnitten durchgeführt. Das Hauptaugenmerk lag dabei auf Glas- und Kohlenstofffaserverstärkungen im Verbund mit Brettschichtholzträgern größeren Querschnitts. Im Zuge eines Forschungsprojekts zu kleinen Gitternetztonnenschalen wurden an der TU-Berlin faserverstärkte Fichtenholzquerschnitte geringer Querschnittsgröße mit Glasfaser- oder Kohlenstofffaserverstärkungen untersucht. In dem vorliegenden Beitrag werden die Ergebnisse zum Trag-, Verbund- und Verformungsverhalten dieser kleinteiligen Lamellenquerschnitte vorgestellt. Im Vergleich zu den bekannten Verstärkungen von Brettschichtholz werden hier sehr hohe effektive Bewehrungsgehalte erreicht. Gleichzeitig ist die zur Verfügung stehende Verbundfläche zwischen Holz und Faserverstärkung deutlich größer. The efficiency of fibre reinforced timber lamellas with reduced hight In recent decades the load bearing mechanisms and composite action of fibre reinforced timber beams were investigated in several research projects, with a focus on the reinforcement of larger timber sections, mainly gluelam beams, with a glass or fibre reinforcement glued to the bottom side of the beam. In contrast, the efficiency of a fibre reinforcement for slender timber lamellas was assessed in a recent research project at the Technische Universität Berlin. The load bearing capacity, composite action and the displacements were tested in different test setups and are presented in this paper. In comparison with the previous research, which concentrated on reinforced gluelam beams, the reinforcement ratios are quite high in the current research project. At the same time the area provided for the bond between timber and fibre reinforcement is comparably higher. [ABSTRACT FROM AUTHOR]

Competing compartment models of different complexities have been used for the quantitative analysis of dynamic contrast-enhanced magnetic resonance imaging data. We present a spatial elastic net approach that allows to estimate the number of compartments for each voxel such that the model complexity is not fixed a priori. A multi-compartment approach is considered, which is translated into a restricted least square model selection problem. This is done by using a set of basis functions for a given set of candidate rate constants. The form of the basis functions is derived from a kinetic model and thus describes the contribution of a specific compartment. Using a spatial elastic net estimator, we chose a sparse set of basis functions per voxel, and hence, rate constants of compartments. The spatial penalty takes into account the voxel structure of an image and performs better than a penalty treating voxels independently. The proposed estimation method is evaluated for simulated images and applied to an in vivo dataset. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Architekten und Ingenieure sind zunehmend daran interessiert, eine moderne Formensprache auch für Holzkonstruktionen umzusetzen. Dabei erweisen sich die bewährten Maßnahmen zum konstruktiven Holzschutz, wie z. B. Dachüberstände, Verkleidungen und Verblechungen, häufig als hinderlich und bremsen so eine größere Verbreitung der Holzbauweise. In der Praxis wurde deshalb vereinzelt ein neues Holzschutzkonzept angewandt, das auf einer hochelastischen, 2 bis 3 mm dicken Sprühbeschichtung aus Polyurethan basiert. Dieses Schutzsystem wird seit 25 Jahren erfolgreich für Betonkonstruktionen eingesetzt. Die hervorragende Risseüberbrückungsfähigkeit der Polyurethan-Dickfilmbeschichtung, zusammen mit einer Dampfdurchlässigkeit von sd ≈ 1,8 m bei 2 bis 3 mm Dicke, prädestiniert sie auch zum Schutz moderner Holzbauteile. In einem Forschungsprojekt an der TU-Berlin wurde dieses Holzschutzkonzept nun erstmals wissenschaftlich an drei unterschiedlichen PUR-Beschichtungen auf verschiedenen Holzgründen wie Brettschichtholz, Brettsperrholz, OSB-Platte, mitteldichte Faserplatte und Furnierschichtholz untersucht. Dazu wurden an gealterten und ungealterten beschichteten Holzproben Zug- und Haftzugtests, Ermüdungstests und Auslagerungsversuche durchgeführt und anschließend die Wasserdichtigkeit geprüft. Des Weiteren wurden ein Fassadenelement im ETAG-Fassadenprüfstand sowie ein Wand-Traufe-Bauteil im Schlagregenversuchsstand getestet. Highly elastic polyurethane coating with 2 to 3 mm thickness for constructive wood protection Architects and engineers develop an increasing interest in sustainable timber structures with a contemporary and modern design. This aim is hampered by the established detailing of timber structures, which for example requires roof overhangs and steel sheet cladding to prevent the timber from weathering. In recent projects architects and engineers tried a new method of constructive wood protection to realize their modern design concepts: A 2 to 3 mm thick, highly elastic polyurethane coating is sprayed onto the wood. This coating is capable of bridging opening gaps, in the tests up to 5 mm in width, while remaining watertight. This type of water proofing is successfully employed on concrete for about 25 years. Its permeability for water vapour with an sd-value of about 1.8 m makes it well suited for timber structures. In a research project the Technische Universität Berlin investigated this new type of wood protection. Polyurethane coatings of three different manufacturers were tested on multiple substrates like gluelam, cross laminated timber, oriented strand board, medium density fibre board and laminated veneer lumber. Half of the test specimens were exposed to artificial weathering before the tests, the other half remained unweathered. Tests of the resistance to delamination were carried out as well as tensile and fatigue tests which were followed by tests assessing the water tightness. Some specimens were exposed to outside climate for two years and a full size facade element was tested in the EOTA facade testing stand. [ABSTRACT FROM AUTHOR]

For the first time, the usage of bromeliad inflorescences as nesting sites for ants and other arthropods was studied. Frequencies of occurrence of nests were recorded from hollow stems of dried infructescences of the bromeliad Vriesea friburgensis on Santa Catarina Island, southern Brazil. Three habitat types were studied: miconietum and two types of restinga, one with low (restingalow) and one with high vegetation cover (restinga-high).Additionally, flower visitation by ants was examined in restinga-low.Out of 619 infructescences, 33% contained nests. Ants were the most frequent occupants (82–96% of nests), followed by termites (3–18%) and bees (0–0.6%). Species accumulation curves and diversity indices indicate that the diversity of stem-occupying ant species is highest in restinga-low (eight species observed, 18 predicted) and lowest in restinga-high (four observed and predicted). Highest similarity of compositions of infructescence-inhabiting ant species was recorded between miconietum and restinga-high, lowest between restinga-low and restinga-high. Similarity between compositions of inflorescence-visiting and infructescence-inhabiting species in restinga-low was even higher (compared with the cases described in the previous sentence) although 50% of the involved species were present in only one of the samples. Altogether, our results indicate that inflorescences are important resources for ants and other nest-building insects from flowering season to past-fruiting season. [ABSTRACT FROM AUTHOR]

ABSTRACT Eyes absent (Eya) is a member of the Retinal Determination Gene Network (RDGN), a set of genes responsible for eye specification in Drosophila. Eya is a dual function protein, working as a transcription factor in the nucleus and as a tyrosine phosphatase in the cytoplasm. It had been shown that Pax and Six family genes, main components of the RDGN, are present in the hydrozoan Cladonema radiatum and that they are expressed in the eye. However, nothing had been known about the Eya family in hydrozoan jellyfish. Here we report the presence of an Eya homologue ( CrEya) in Cladonema. Real-time PCR analysis and in situ hybridization showed that CrEya is expressed in the eye. Furthermore, the comprehensive survey of eukaryote genomes revealed that the acquisition of the N-terminal transactivation domain, including the EYA Domain 2 and its adjacent sequence shared by all eumetazoans, happened early in evolution, before the separation of Cnidaria and Bilateria. Our results uncover the evolution of the two domains and show a conservation of the expression pattern of the Eya gene between Cnidaria and Bilateria, which, together with previous data, supports the hypothesis of the monophyletic origin of metazoans eyes. We additionally show that CrEya is also expressed in the oocytes, where two other members of the RDGN, CrPaxB, and Six4/5-Cr, are known to be expressed. These data suggest that several members of the RDGN have begun to be localized also into the different context of egg development early in the course of metazoan evolution. J. Exp. Zool. (Mol. Dev. Evol.) 318:257-267, 2012. © 2012 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Three-dimensional structured illumination microscopy (3D-SIM) has opened up new possibilities to study nuclear architecture at the ultrastructural level down to the ∼100 nm range. We present first results and assess the potential using 3D-SIM in combination with 3D fluorescence in situ hybridization (3D-FISH) for the topographical analysis of defined nuclear targets. Our study also deals with the concern that artifacts produced by FISH may counteract the gain in resolution. We address the topography of DAPI-stained DNA in nuclei before and after 3D-FISH, nuclear pores and the lamina, chromosome territories, chromatin domains, and individual gene loci. We also look at the replication patterns of chromocenters and the topographical relationship of Xist-RNA within the inactive X-territory. These examples demonstrate that an appropriately adapted 3D-FISH/3D-SIM approach preserves key characteristics of the nuclear ultrastructure and that the gain in information obtained by 3D-SIM yields new insights into the functional nuclear organization. [ABSTRACT FROM AUTHOR]

To investigate the population structure of the obligate plant-ant Pseudomyrmex ferrugineus, we developed primers for 12 microsatellite loci. We tested the variability of the markers on 11 individuals from each of two populations (totalling 22 individuals) and found two to 12 alleles per locus and population. No deviations from Hardy–Weinberg equilibrium were detected. Observed and expected heterozygosities at each locus ranged from 0.00 to 0.50 and from 0.08 to 0.46, respectively. We also investigated suitability of these primers in two congeneric species. [ABSTRACT FROM AUTHOR]

Imaging in clinical oncology trials provides a wealth of information that contributes to the drug development process, especially in early phase studies. This article focuses on kinetic modeling in DCE-MRI, inspired by mixed-effects models that are frequently used in the analysis of clinical trials. Instead of summarizing each scanning session as a single kinetic parameter-such as median ktrans across all voxels in the tumor ROI-we propose to analyze all voxel time courses from all scans and across all subjects simultaneously in a single model. The kinetic parameters from the usual nonlinear regression model are decomposed into unique components associated with factors from the longitudinal study; e.g., treatment, patient, and voxel effects. A Bayesian hierarchical model provides the framework to construct a data model, a parameter model, as well as prior distributions. The posterior distribution of the kinetic parameters is estimated using Markov chain Monte Carlo (MCMC) methods. Hypothesis testing at the study level for an overall treatment effect is straightforward and the patient- and voxel-level parameters capture random effects that provide additional information at various levels of resolution to allow a thorough evaluation of the clinical trial. The proposed method is validated with a breast cancer study, where the subjects were imaged before and after two cycles of chemotherapy, demonstrating the clinical potential of this method to longitudinal oncology studies. Magn Reson Med 61:163-174, 2009. © 2008 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

The distinction between soma and germline is an important process in the development of animals with sexual reproduction. It is regulated by a number of germline-specific genes, most of which appear conserved in evolution and therefore can be used to study the formation of the germline in diverged animal groups. Here we report the isolation of two orthologs of one such gene, nanos ( nos), in the cnidarian Podocoryne carnea, a species with representative zoological features among the hydrozoans. By studying nos gene expression throughout the Podocoryne biphasic life cycle, we find that the germline differentiates exclusively during medusa development, whereas the polyp does not contribute to the process. An early widespread nos expression in developing medusae progressively refines into a mainly germline-specific pattern at terminal stages of medusa formation. Thus, the distinction between germline and soma is a late event in hydrozoan development. Also, we show that the formation of the medusa is a de novo process that relies on active local cell proliferation and differentiation of novel cell and tissue types not present in the polyp, including nos-expressing cells. Finally, we find nos expression at the posterior pole of Podocoryne developing embryos, not related to germline formation. This second aspect of nos expression is also found in Drosophila, where nos functions as a posterior determinant essential for the formation of the fly abdomen. This raises the possibility that nos embryonic expression could play a role in establishing axial polarity in cnidarians. [ABSTRACT FROM AUTHOR]

The elongate twig ant Pseudomyrmex gracilis is widely distributed in the New World ranging from southern USA to Brazil and northern Argentina. To investigate its within-colony relatedness, we developed primers for nine polymorphic microsatellite loci. High levels of within-population variation were observed, with number of alleles ranging from two to 13, and heterozygosity from 0.28 to 0.90. The loci showed no deviations from Hardy–Weinberg equilibrium and no linkage disequilibrium. [ABSTRACT FROM AUTHOR]