bluuebunny/crossref_metadata_2025 huggingface dataset:
Photoactive spherical colloids for opal photonic crystals
Authors: Comoretto Davide , Robbiano Valentina , Canazza Giancarlo , Boarino Luca , Panzarasa Guido , Laus Michele , Sparnacci Katia
Published: April 2013

The synthesis and characterization of submicrometer‐sized polymer particles, functionalized by different techniques with fluorescent dyes and featuring tunable surface charges, are described. Dyes with a polymerizable moiety were incorporated during emulsifier‐free or seeded emulsion polymerization, whereas non‐polymerizable dyes were included into preformed nanoparticles by a swelling and deswelling process. The particle surface charge was controlled through the choice of suitable initiators. All the nanoparticles were successfully used to grow high optical quality opal photonic crystals by the vertical deposition technique. Optical characterization of such photonic crystals pointed out the presence of the optical stop band and the high‐energy van Hove‐like structures, both scaling with the particle diameter according to the scaling laws of photonic crystals and possessing the expected angular dispersion. These results are indicative of the high size uniformity and of the surface quality of the nanospheres independently on the synthetic method adopted. Preliminary data seem to suggest some effect of the opal photonic band structure on the dye fluorescence spectra. POLYM. COMPOS., 34:1443–1450, 2013. © 2013 Society of Plastics Engineers.
Impact of chorionicity on first‐trimester nuchal translucency screening in ART twin pregnancies
Authors: Flöck A. , Reinsberg J. , Berg C. , Gembruch U. , Geipel A.
Published: April 2013

Objective

Nuchal translucency (NT) measurement in assisted reproduction treatment (ART) twins is less extensively investigated. Therefore, the present study compared NT measurements of spontaneously conceived twins with ART twins in dichorionic (DC) and monochorionic (MC) pregnancies.

Methods

Retrospective analysis of 706 unaffected twins between 11 + 0 and 13 + 6 weeks conceived either spontaneously (n = 362) or with ART (n = 344). The group with spontaneous conception included 234 DC (64.6%) and 128 MC (35.4%) pregnancies. In the ART group, 326 were DC (94.7%) and 18 were MC (5.3%). NT values were transformed into multiples of median (MoM).

Results

In the DC group, no significant differences between ART and spontaneously conceived twins (NT MoM 1.06 ± 0.28 vs 1.03 ± 0.29; p > 0.05) were observed. NT MoM of MC ART twins was higher compared with spontaneous MC twins (1.23 ± 0.82 vs 0.99 ± 0.27; p = 0.011). Although the incidence of twin‐to‐twin transfusion syndrome (TTTS) was higher among ART twins (11.1% vs 4.7%), inter‐twin NT difference was similar between pregnancies with TTTS (0.42 ± 0.21) or without (0.40 ± 0.71).

Conclusions

Measurement of NT thickness in DC ART twins achieves comparable results with twins conceived spontaneously. Conclusions in MC twins are limited; however, higher NT MoM was not related to TTTS or selective intrauterine growth restriction. © 2013 John Wiley & Sons, Ltd.
Modulation of electronic properties of π‐conjugated copolymers derived from naphtho[1,2‐b:5,6‐b′]dithiophene donor unit: A structure‐property relationship study
Authors: Dutta Pranabesh , Park Hanok , Oh Minjae , Bagde Sushil , Kang In Nam , Lee Soo‐Hyoung
Published: April 2013

A set of three donor‐acceptor conjugated (D‐A) copolymers were designed and synthesized via Stille cross‐coupling reactions with the aim of modulating the optical and electronic properties of a newly emerged naphtho[1,2‐b:5,6‐b′]dithiophene donor unit for polymer solar cell (PSCs) applications. The PTNDTT‐BT, PTNDTT‐BTz, and PTNDTT‐DPP polymers incorporated naphtho[1,2‐b:5,6‐b′]dithiophene (NDT) as the donor and 2,2′‐bithiazole (BTz), benzo[1,2,5]thiadiazole (BT), and pyrrolo[3,4‐c]pyrrole‐1,4(2H,5H)‐dione (DPP), as the acceptor units. A number of experimental techniques such as differential scanning calorimetry, thermogravimetry, UV–vis absorption spectroscopy, cyclic voltammetry, X‐ray diffraction, and atomic force microscopy were used to determine the thermal, optical, electrochemical, and morphological properties of the copolymers. By introducing acceptors of varying electron withdrawing strengths, the optical band gaps of these copolymers were effectively tuned between 1.58 and 1.9 eV and their HOMO and LUMO energy levels were varied between −5.14 to −5.26 eV and −3.13 to −3.5 eV, respectively. The spin‐coated polymer thin film exhibited p‐channel field‐effect transistor properties with hole mobilities of 2.73 × 10−3 to 7.9 × 10−5 cm2 V−1 s−1. Initial bulk‐heterojunction PSCs fabricated using the copolymers as electron donor materials and [6,6]‐phenyl C71 butyric acid methyl ester (PC71BM) as the acceptor resulted in power conversion efficiencies in the range of 0.67–1.67%. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 2948–2958
Polymerization of (E)‐1,3‐Pentadiene and (E)‐2‐methyl‐1,3‐pentadiene with neodymium catalysts: Examination of the factors that affect the stereoselectivity
Authors: Leone Giuseppe , Caterina Boccia Antonella , Ricci Giovanni , Giarrusso Antonino , Porri Lido
Published: April 2013

(E)‐1,3‐Pentadiene (EP) and (E)‐2‐methyl‐1,3‐pentadiene (2MP) were polymerized to cis‐1,4 polymers with homogeneous and heterogeneous neodymium catalysts to examine the influence of the physical state of the catalyst on the polymerization stereoselectivity. Data on the polymerization of (E)‐1,3‐hexadiene (EH) are also reported. EP and EH gave cis‐1,4 isotactic polymers both with the homogeneous and with the heterogeneous system, whereas 2MP gave an isotactic cis‐1,4 polymer with the heterogeneous catalyst and a syndiotactic cis‐1,4 polymer, never reported earlier, with the homogeneous one. For comparison, the results obtained with the soluble CpTiCl3‐based catalyst (Cp = cyclopentadienyl), which gives cis‐1,4 isotactic poly(2MP), are examined. A tentative interpretation is given for the mechanism of the formation of the stereoregular polymers obtained and a complete NMR characterization of the cis‐1,4‐syndiotactic poly(2MP) is reported. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 3227–3232
Liquid Droplet excitation of freestanding poly(methyl methacrylate)/graphene oxide films for mechanical energy harvesting
Authors: Valentini Luca , Bon Silvia Bittolo , Kenny Josè
Published: April 2013

A simple and solvent‐free practical way to obtain freestanding poly(methyl methacrylate)/graphene oxide films is reported. Falling liquid droplets are used to produce an impulse necessary for the mechanical excitation of such composite films. A pressure wave is generated on the surface of the films by the impact. It is reported how such films are able to convert mechanical energy of the impact to electrical power. The reported example is of interest to enhance the mechanical energy harvesting and to add new functionalities to traditional polymer nanocomposites. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2013, 51, 1028–1032
The influence of dispositional optimism on post‐visit anxiety and risk perception accuracy among breast cancer genetic counselees
Authors: Wiering B. M. , Albada A. , Bensing J. M. , Ausems M. G. E. M. , van Dulmen A. M.
Published: April 2013

Objective

Much is unknown about the influence of dispositional optimism and affective communication on genetic counselling outcomes. This study investigated the influence of counselees' optimism on the counselees' risk perception accuracy and anxiety, while taking into account the affective communication during the first consultation for breast cancer genetic counselling.

Methods

Counselees completed questionnaires measuring optimism, anxiety and the perceived risk that hereditary breast cancer runs in the family before, and anxiety and perceived risk after the first consultation. Consultations were videotaped. The duration of eye contact was measured, and verbal communication was rated using the Roter Interaction Analysis System.

Results

Less‐optimistic counselees were more anxious post‐visit (β = −.29; p = .00). Counsellors uttered fewer reassuring statements if counselees were more anxious (β = −.84; p = .00) but uttered more reassurance if counselees were less optimistic (β = −.76; p = .01). Counsellors expressed less empathy if counselees perceived their risk as high (β = −1.51; p = .04). An increase in the expression of reassurance was related to less post‐visit anxiety (β = −.35; p = .03). More empathy was related to a greater overestimation of risk (β = .92; p = .01).

Conclusions

Identification of a lack of optimism as a risk factor for high anxiety levels enables the adaptation of affective communication to improve genetic counselling outcomes. Because reassurance was related to less anxiety, beneficial adaptation is attainable by increasing counsellors' reassurance, if possible. Because of a lack of optimally adapted communication in this study, further research is needed to clarify how to increase counsellors' ability to adapt to counselees. Copyright © 2013 John Wiley & Sons, Ltd.
Extending Airborne Electromagnetic Surveys for Regional Active Layer and Permafrost Mapping with Remote Sensing and Ancillary Data, Yukon Flats Ecoregion, Central Alaska
Authors: Pastick Neal J. , Jorgenson M. Torre , Wylie Bruce K. , Minsley Burke J. , Ji Lei , Walvoord Michelle A. , Smith Bruce D. , Abraham Jared D. , Rose Joshua R.
Published: April 2013

Machine‐learning regression tree models were used to extrapolate airborne electromagnetic resistivity data collected along flight lines in the Yukon Flats Ecoregion, central Alaska, for regional mapping of permafrost. This method of extrapolation (r = 0.86) used subsurface resistivity, Landsat Thematic Mapper (TM) at‐sensor reflectance, thermal, TM‐derived spectral indices, digital elevation models and other relevant spatial data to estimate near‐surface (0–2.6‐m depth) resistivity at 30‐m resolution. A piecewise regression model (r = 0.82) and a presence/absence decision tree classification (accuracy of 87%) were used to estimate active‐layer thickness (ALT) (< 101 cm) and the probability of near‐surface (up to 123‐cm depth) permafrost occurrence from field data, modelled near‐surface (0–2.6 m) resistivity, and other relevant remote sensing and map data. At site scale, the predicted ALTs were similar to those previously observed for different vegetation types. At the landscape scale, the predicted ALTs tended to be thinner on higher‐elevation loess deposits than on low‐lying alluvial and sand sheet deposits of the Yukon Flats. The ALT and permafrost maps provide a baseline for future permafrost monitoring, serve as inputs for modelling hydrological and carbon cycles at local to regional scales, and offer insight into the ALT response to fire and thaw processes. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.
Crystal structure of deltarhodopsin‐3 from Haloterrigena thermotolerans
Authors: Zhang Jin , Mizuno Katsuhide , Murata Yuki , Koide Hideaki , Murakami Midori , Ihara Kunio , Kouyama Tsutomu
Published: April 2013

Deltarhodopsin, a new member of the microbial rhodopsin family, functions as a light‐driven proton pump. Here, we report the three‐dimensional structure of deltarhodopsin (dR3) from Haloterrigena thermotolerans at 2.7 Å resolution. A crystal belonging to space group R32 (a, b = 111.71 Å, c = 198.25 Å) was obtained by the membrane fusion method. In this crystal, dR3 forms a trimeric structure as observed for bacteriorhodopsin (bR). Structural comparison of dR with bR showed that the inner part (the proton release and uptake pathways) is highly conserved. Meanwhile, residues in the protein–protein contact region are largely altered so that the diameter of the trimeric structure at the cytoplasmic side is noticeably larger in dR3. Unlike bR, dR3 possesses a helical segment at the C‐terminal region that fills the space between the AB and EF loops. A significant difference is also seen in the FG loop, which is one residue longer in dR3. Another peculiar property of dR3 is a highly crowded distribution of positively charged residues on the cytoplasmic surface, which may be relevant to a specific interaction with some cytoplasmic component.Proteins 2013; © 2013 Wiley Periodicals, Inc.
Nisin adsorption on hydrophilic and hydrophobic surfaces: evidence of its interactions and antibacterial activity
Authors: Karam Layal , Jama Charafeddine , Nuns Nicolas , Mamede Anne‐Sophie , Dhulster Pascal , Chihib Nour‐Eddine
Published: April 2013

Study of peptides adsorption on surfaces remains a current challenge in literature. A complementary approach, combining X‐ray photoelectron spectroscopy (XPS) and time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS) was used to investigate the antimicrobial peptide nisin adsorption on hydrophilic and hydrophobic surfaces. The native low density polyethylene was used as hydrophobic support and it was grafted with acrylic acid to render it hydrophilic. XPS permitted to confirm nisin adsorption and to determine its amount on the surfaces. ToF‐SIMS permitted to identify the adsorbed bacteriocin type and to observe its distribution and orientation behavior on both types of surfaces. Nisin was more oriented by its hydrophobic side to the hydrophobic substrate and by its hydrophilic side to the outer layers of the adsorbed peptide, in contrast to what was observed on the hydrophilic substrate. A correlation was found between XPS and ToF‐SIMS results, the types of interactions on both surfaces and the observed antibacterial activity. Such interfacial studies are crucial for better understanding the peptides interactions and adsorption on surfaces and must be considered when setting up antimicrobial surfaces. Copyright © 2013 European Peptide Society and John Wiley & Sons, Ltd.
Individual and Geographic Factors in the Formation of Care Networks in the UK
Authors: Bell David , Rutherford Alasdair
Published: April 2013

This paper argues that geography plays a crucial role in the formation of care networks. The role of informal carers will become increasingly important as the population ages and a better understanding of the drivers and outcome of these locational decisions is important. We use data from the British Household Panel Survey to explore the characteristics of common forms of care network; to investigate the factors that may influence the type of care network formed when a need for care is identified and to examine the role of space in the formation of care networks. Our results show the importance of both individual and geographic factors in network formation. Copyright © 2013 John Wiley & Sons, Ltd.
A Bayesian non‐inferiority test for two independent binomial proportions
Authors: Kawasaki Yohei , Miyaoka Etsuo
Published: April 2013

In drug development, non‐inferiority tests are often employed to determine the difference between two independent binomial proportions. Many test statistics for non‐inferiority are based on the frequentist framework. However, research on non‐inferiority in the Bayesian framework is limited. In this paper, we suggest a new Bayesian index τ = P(π1 > π2 − Δ0 | X1,X2), where X1 and X2 denote binomial random variables for trials n1 and n2, and parameters π1 and π2, respectively, and the non‐inferiority margin is Δ0 > 0. We show two calculation methods for τ, an approximate method that uses normal approximation and an exact method that uses an exact posterior PDF. We compare the approximate probability with the exact probability for τ. Finally, we present the results of actual clinical trials to show the utility of index τ. Copyright © 2013 John Wiley & Sons, Ltd.
Morphology of fungal stains on paper characterized with multi‐scale and multi‐sensory surface metrology
Authors: Szcepanowska Hanna , Mathia Thomas G. , Belin Patrice
Published: April 2013

Pigmentation of paper induced by fungi is one of the most complex phenomenons because it involves living organisms growing on a heterogeneous paper substrate. A novel approach to the study of interfaces of fungi and paper in black stains produced by pigmented Dematiaceous fungi with meristematic growth was undertaken applying surface metrology techniques: confocal laser SCANNING 36:76–85, 2014. © 2013 Wiley Periodicals, Inc.
Concentration induced the interfacial self‐assembly polymorphism of 4, 4′‐dihexadecyloxy‐benzophenon by scanning tunneling microscopy
Authors: Xie Ying , Li Yijing , Miao Xinrui
Published: April 2013

The concentration effect on a two‐dimensional (2D) self‐assembly of 4, 4′‐dihexadecyloxy‐benzophenon (DHB) has been investigated by scanning tunneling microscopy. The self‐assembly of DHB at the phenyloctane/graphite interface was concentration dependent. Under low concentration, the DHB molecules were adsorbed intactly on the graphite surface. With the increasing of concentration, one of side chains connecting the conjugated moiety stretched into the liquid phase. The coexistence of two self‐assembled structures was observed in a moderate concentration. The result indicated that the van der Waals interactions between the molecules and the graphite lattice were decreasing with the increasing concentration. After the samples were placed in ambient conditions over 24 h, a different self‐assembled structure was obtained on the gas/solid interface, in which the DHB molecules were adsorbed on the surface with only one of the side chains. Both the benzophenon core and the other side chain were extended to the gas phase. The results demonstrated that concentration played an important role in forming the 2D molecular self‐assembly and provided an efficient approach for the control of the DHB molecular nanostructure. Copyright © 2013 John Wiley & Sons, Ltd.
Perceived Unfairness at Work, Social and Personal Resources, and Resting Blood Pressure
Authors: Ford Michael T.
Published: April 2013

By drawing from theoretical perspectives suggesting that unfair conditions threaten fundamental psychological needs, perceived unfairness at work was proposed and tested as a predictor of resting blood pressure. As part of the Midlife Development in the United States Biomarkers project, participants completed questionnaires measuring perceived unfairness, self‐esteem and coworker support. Resting blood pressure readings were also recorded as part of a larger physical examination. Results indicate that perceived unfairness at work was associated with higher resting diastolic and systolic blood pressure. Perceived unfairness was most strongly related to diastolic and systolic blood pressure among women with low levels of coworker support. Contrary to predictions, self‐esteem did not moderate the association between perceived unfairness and blood pressure. These results suggest that high blood pressure may be a mechanism linking unfairness to negative health outcomes and point to coworker support as a moderator of the perceived unfairness–blood pressure relationship among women. Further research is needed exploring the mediating mechanisms linking unfair treatment at work to blood pressure and health. Copyright © 2013 John Wiley & Sons, Ltd.
Metrics for quantifying evolutionary changes in Z specifications
Authors: Bollin Andreas
Published: April 2013

This article proposes metrics for quantifying changes throughout the evolution of formal software specifications in long living systems. Formal specifications play an important role in the software development life‐cycle by supporting refinement and proof and by providing a basis for comprehension and maintenance activities. However, specifications also undergo evolutionary changes, and these changes are hard to assess because of a lack of suitable measures.

This paper proposes and analyzes a set of measures for estimating aspects of a specification's complexity and quality. The measures are based on existing measures for source code, but they have been redefined in the scope of formal Z specifications. Geared towards Z, they are then evaluated concerning their expressiveness by a case study that comprises more than 65,000 lines of specification text. Finally, the usability of the measures is demonstrated on the Z specification of the Web Service Definition Language during its evolution over a period of about 3 years. Copyright © 2013 John Wiley & Sons, Ltd.
Cure behavior and antimicrobial performance of sulfur‐cured natural rubber vulcanizates containing 2‐hydroxypropyl‐3‐piperazinylquinolinecarboxylic acid methacrylate or silver‐substituted zeolite
Authors: Jai‐eau Kanisorn , Wimolmala Ekachai , Sombatsompop Narongrit
Published: April 2013

This work used 2‐hydroxypropyl‐3‐piperazinylquinolinecarboxylic acid methacrylate (HPQM) or silver‐substituted zeolite (SSZ) as antibacterial agents for natural rubber (NR) compounds vulcanized by conventional vulcanization (CV), semi‐efficient vulcanization, and efficient vulcanization (EV) systems. The cure behavior and antibacterial performance of the NR vulcanizates were studied by varying the loadings of HPQM or SSZ, contact times, and vulcanization systems. The antibacterial performance of the rubber compounds was examined by halo test and plate‐count‐agar methods against Escherichia coli (E. coli, ATCC 25922) and Staphylococcus aureus (S. aureus, ATCC 25923) as the testing bacteria. The cure time and crosslink density were dependent on the vulcanization recipe used but were not affected by the addition of HPQM or SSZ. Diphenylguanidine at the level of 1.0 phr (parts by weight per hundred parts of resin) in NR vulcanized by the EV system had the ability to kill the E. coli and S. aureus bacteria. The NR vulcanized by the CV system showed the most pronounced antibacterial performance, as compared with the other two vulcanization systems, via migration and diffusion of HPQM or SSZ onto the NR surfaces, this being identified by the relatively large reduction of contact angle values. The HPQM showed the most preference for NR compounds vulcanized with the CV system with a contact time of 120 min or longer to achieve a bacteria‐killing efficacy of 99.0–99.9%, the efficacy being more pronounced for E. coli bacteria. J. VINYL ADDIT. TECHNOL., 19:123–131, 2013. © 2013 Society of Plastics Engineers
Synthesis of Fe3O4/polyaniline nanocomposite and its application for nitrate removal from aqueous solutions
Authors: Katal Reza , Pourkarimi Sara , Bahmani Ehsan , Dehkordi Hamed Aleebrahim , Ghayyem Mohhamad Ali , Esfandian Hussein
Published: April 2013

The aim of this work was to investigate the sorption characteristics of Fe3O4 coated on polyaniline (Fe3O4/PAn) for the removal of NO3− ions from aqueous solutions. The sorption of NO3− ions by the batch method was carried out. The optimum conditions of sorption were found to be a Fe3O4/PAn dose of 0.4 g in 100 mL of NO3− solution, a contact time of 10 min, pH and temperature 7 and 40°C, respectively. Temperature had a negative effect on the removal efficiency. Three equations, i.e., Morris–Weber, Lagergren, and pseudo‐second‐order, were tested to track the kinetics of the removal process. The Langmuir, Freundlich, and Dubinin–Radushkevich isotherm models were subjected to sorption data in order to estimate sorption capacity, intensity, and energy. The thermodynamic parameters ΔH, ΔS, and ΔG were evaluated. They showed that the adsorption of NO3− onto Fe3O4/PAn was feasible, spontaneous, and exothermic under the studied conditions. It can be concluded that Fe3O4/PAn has potential to remove NO3− ions from aqueous solutions at different concentrations. The system Fe3O4/Pan was successfully tested for a high removal efficiency of NO3− from urban wastewater. J. VINYL ADDIT. TECHNOL., 19:147–156, 2013. © 2013 Society of Plastics Engineers
A model for the structural dynamic response of the CX‐100 wind turbine blade
Authors: Fleming Ian , Luscher D.J.
Published: April 2013

A geometrically exact beam model for simulating the structural dynamic response of the CX‐100 wind turbine blade is presented. The underlying geometrically nonlinear theory is detailed, and its implementation into a finite‐element code, NLBeam, developed as part of this research is outlined. The parameters used to represent the varying cross‐sectional distributions of stiffness and mass are calculated consistent with the geometrically exact beam theory by using the variational asymptotic method, as developed by Hodges and Yu et al. through the commercially available code, (VABS) variational asymptotic beam sectional analysis. Code and calculation verification are documented through a systematic grid convergence study applied independently to both the cross‐sectional, and static and dynamic beam simulations. An initial assessment of the model is made by comparing simulation results with experimental test data for three cases: quasistatic loading, linearized modal dynamic behavior and steady‐state oscillating dynamic loads. Simulation results are shown to be in reasonable agreement with experimental data. Future improvements to the model, as well as additional experimental characterization that can benefit such modeling efforts, are outlined. Copyright © 2013 John Wiley & Sons, Ltd.
Increased heart rate caused by atrial pacing with the closed‐loop stimulation function prevented micturition syncope
Authors: Haraki Tatsuo , Hirase Hiroaki , Kitazaki Kentaro , Ishikawa Norio
Published: April 2013

A 70‐year‐old man had been experiencing syncope several times a year. We implanted a DDD pacemaker with closed‐loop stimulation (CLS) function. When he urinated early in the morning, his increased atrial pacing rates elevated his heart rate (HR) during and after micturition. After implantation of the DDD‐CLS mode, he did not experience symptoms. In contrast, in the DDD‐R mode, his intrinsic HR changed to atrial pacing after micturition but decreased to the basal rate within 2 min, and he experienced a sense of cold perspiration and presyncope. Increased HRs caused by atrial pacing with the CLS function were useful in the prevention of micturition syncope.
Körperliche Beanspruchung und physische Belastungen bei der Arbeit – ein abnehmendes Public Health-Problem?
Authors: Latza Ute , Liebers Falk , Franke Franziska
Published: April 2013

Einleitung

Physische Arbeitsbelastungen (z.B. Lastenhandhabung) werden von Erwerbstätigen noch immer häufig angegeben und können mit hohen psychosozialen Belastungen (z.B. Termindruck) verbunden sein. In bevölkerungsmäßig relevanten Berufsgruppen mit ungünstigen physischen Arbeitsbedingungen (Agrar-, manuelle und gering qualifizierte Dienstleistungsberufe) treten relativ häufig AU-Fälle aufgrund von Muskel-Skelett-Erkrankungen auf. Die Prävention arbeitsbedingter Gesundheitsfolgen bleibt Public Health-relevant.
Sport als Möglichkeit für Gesundheitsförderung bei Migrantinnen
Authors: Röger-Offergeld Ulrike , Rütten Alfred
Published: April 2013

Einleitung

Menschen mit Migrationshintergrund weisen häufig erhöhte Gesundheitsrisiken auf. Auslöser sind v.a. ungünstige Lebens- und Arbeitsbedingungen, von denen besonders Migrantinnen betroffen sind (vgl. RKI, 2008). Körperlich-sportliche Aktivität kann nachweislich zur Gesundheitsförderung beitragen. Jedoch sind Migrantinnen vergleichsweise wenig körperlich-sportlich aktiv (vgl. Kleindienst-Cachay et al., 2012). Dieser Beitrag geht der Frage nach, wie Migrantinnen mit körperlich-sportlicher Aktivität erreicht und adäquate Angebote für diese Zielgruppe implementiert werden können.
Direct numerical simulation of complete H-type and K-type transitions with implications for the dynamics of turbulent boundary layers
Authors: Sayadi Taraneh , Hamman Curtis W. , Moin Parviz
Published: April 2013

The onset and development of turbulence from controlled disturbances in compressible ($\mathit{Ma}= 0. 2$), flat-plate boundary layers is studied by direct numerical simulation. We have validated the initial disturbance development, confirmed that H- and K-regime transitions were reproduced and, from these starting points, we carried these simulations beyond breakdown, past the skin-friction maximum and to higher Reynolds numbers than investigated before to evaluate how these two flow regimes converge towards turbulence and what transitional flow structures embody the statistics and mean dynamics of developed turbulence. We show that H- and K-type breakdowns both relax toward the same statistical structure typical of developed turbulence at high Reynolds number immediately after the skin-friction maximum. This threshold marks the onset of self-sustaining mechanisms of near-wall turbulence. At this point, computed power spectra exhibit a decade of Kolmogorov inertial subrange; this is further evidence of convergence to equilibrium turbulence at the late stage of transition. Here, visualization of the instantaneous flow structure shows numerous, tightly packed hairpin vortices (Adrian, Phys. Fluids, vol. 19, 2007, 041301). Strongly organized coherent hairpin structures are less perceptible farther downstream (at higher Reynolds numbers), but the flow statistics and near-wall dynamics are the same. These structurally simple hairpin-packet solutions found in the very late stages of H- and K-type transitions obey the statistical measurements of higher-Reynolds-number turbulence. Comparison with the bypass transition of Wu & Moin (Phys. Fluids, vol. 22, 2010, pp. 85–105) extends these observations to a wider class of transitional flows. In contrast to bypass transition, the (time- and spanwise-averaged) skin-friction maximum in both H- and K-type transitions overshoots the turbulent correlation. Downstream of these friction maxima, all three skin-friction profiles collapse when plotted versus the momentum-thickness Reynolds number, ${\mathit{Re}}_{\theta } $. Mean velocities, turbulence intensities and integral parameters collapse generally beyond ${\mathit{Re}}_{\theta } = 900$ in each transition scenario. Skin-friction maxima, organized hairpin vortices and the onset of self-sustaining turbulence found in controlled H- and K-type transitions are, in many dynamically important respects, similar to development of turbulent spots seen by Park et al. (Phys. Fluids, vol. 24, 2012, 035105). A detailed statistical comparison demonstrates that each of these different transition scenarios evolve into a unique force balance characteristic of higher-Reynolds-number turbulence (Klewicki, Ebner & Wu, J. Fluid Mech., vol. 682, 2011, pp. 617–651). We postulate that these dynamics of late-stage transition as manifested by hairpin packets can serve as a reduced-order model of high-Reynolds-number turbulent boundary layers.
On non-Oberbeck–Boussinesq effects in three-dimensional Rayleigh–Bénard convection in glycerol
Authors: Horn Susanne , Shishkina Olga , Wagner Claus
Published: April 2013

Rayleigh–Bénard convection in glycerol (Prandtl number $\mathit{Pr}= 2547. 9$) in a cylindrical cell with an aspect ratio of $\Gamma = 1$ was studied by means of three-dimensional direct numerical simulations (DNS). For that purpose, we implemented temperature-dependent material properties into our DNS code, by prescribing polynomial functions up to seventh order for the viscosity, the heat conductivity and the density. We performed simulations with the common Oberbeck–Boussinesq (OB) approximation and with non-Oberbeck–Boussinesq (NOB) effects within a range of Rayleigh numbers of $1{0}^{5} \leq \mathit{Ra}\leq 1{0}^{9} $. For the highest temperature differences, $\Delta = 80~\mathrm{K} $, the viscosity at the top is ${\sim }360\hspace{0.167em} \% $ times higher than at the bottom, while the differences of the other material properties are less than $15\hspace{0.167em} \% $. We analysed the temperature and velocity profiles and the thermal and viscous boundary-layer thicknesses. NOB effects generally lead to a breakdown of the top–bottom symmetry, typical for OB Rayleigh–Bénard convection. Under NOB conditions, the temperature in the centre of the cell ${T}_{c} $ increases with increasing $\Delta $ and can be up to $15~\mathrm{K} $ higher than under OB conditions. The comparison of our findings with several theoretical and empirical models showed that two-dimensional boundary-layer models overestimate the actual ${T}_{c} $, while models based on the temperature or velocity scales predict ${T}_{c} $ very well with a standard deviation of $0. 4~\mathrm{K} $. Furthermore, the obtained temperature profiles bend closer towards the cold top plate and further away from the hot bottom plate. The situation for the velocity profiles is reversed: they bend farther away from the top plate and closer towards to the bottom plate. The top boundary layers are always thicker than the bottom ones. Their ratio is up to 2.5 for the thermal and up to 4.5 for the viscous boundary layers. In addition, the Reynolds number $\mathit{Re}$ and the Nusselt number $\mathit{Nu}$ were investigated: $\mathit{Re}$ is higher and $\mathit{Nu}$ is lower under NOB conditions. The Nusselt number $\mathit{Nu}$ is influenced in a nonlinear way by NOB effects, stronger than was suggested by the two-dimensional simulations. The actual scaling of $\mathit{Nu}$ with $\mathit{Ra}$ in the NOB case is $\mathit{Nu}\propto {\mathit{Ra}}^{0. 298} $ and is in excellent agreement with the experimental data.
The dam-break problem for concentrated suspensions of neutrally buoyant particles
Authors: Ancey C. , Andreini N. , Epely-Chauvin G.
Published: April 2013

This paper addresses the dam-break problem for particle suspensions, that is, the flow of a finite volume of suspension released suddenly down an inclined flume. We were concerned with concentrated suspensions made up of neutrally buoyant non-colloidal particles within a Newtonian fluid. Experiments were conducted over wide ranges of slope, concentration and mass. The major contributions of our experimental study are the simultaneous measurement of local flow properties far from the sidewalls (velocity profile and, with lower accuracy, particle concentration) and macroscopic features (front position, flow depth profile). To that end, the refractive index of the fluid was adapted to closely match that of the particles, enabling data acquisition up to particle volume fractions of 60 %. Particle migration resulted in the blunting of the velocity profile, in contrast to the parabolic profile observed in homogeneous Newtonian fluids. The experimental results were compared with predictions from lubrication theory and particle migration theory. For solids fractions as large as 45 %, the flow behaviour did not differ much from that of a homogeneous Newtonian fluid. More specifically, we observed that the velocity profiles were closely approximated by a parabolic form and there was little evidence of particle migration throughout the depth. For particle concentrations in the 52–56 % range, the flow depth and front position were fairly well predicted by lubrication theory, but taking a closer look at the velocity profiles revealed that particle migration had noticeable effects on the shape of the velocity profile (blunting), but had little impact on its strength, which explained why lubrication theory performed well. Particle migration theories (such as the shear-induced diffusion model) successfully captured the slow evolution of the velocity profiles. For particle concentrations in excess of 56 %, the macroscopic flow features were grossly predicted by lubrication theory (to within 20 % for the flow depth, 50 % for the front position). The flows seemed to reach a steady state, i.e. the shape of the velocity profile showed little time dependence.
Global stability of the rotating-disc boundary layer with an axial magnetic field
Authors: Thomas Christian , Davies Christopher
Published: April 2013

A numerical study is conducted to investigate the influence of a uniform axial magnetic field on the global linear stability of the rotating-disc boundary layer. Simulation results obtained using a radially homogenized base flow were found to be in excellent agreement with an earlier linear stability analysis, which indicated that an axial magnetic field can locally suppress both convective and absolute instabilities. However, the numerical results obtained for the genuine, radially inhomogeneous, flow indicate that a global form of instability develops for sufficiently large magnetic fields. The qualitative nature of the global instability is similar to that which was observed in a previous study, where mass suction was applied at the rotating disc surface. It is shown that, just as for the case with mass suction, it is possible to explain the promotion of global instability by considering a model that includes detuning effects, which are associated with the radial variation of locally defined absolute temporal frequencies. The recurrence of the same type of instability behaviour when two distinct flow control strategies are implemented, one using suction and the other an axial magnetic field, indicates that the phenomena described by the model may be considered generic.
Advection and buoyancy-induced turbulent mixing in a narrow vertical tank
Authors: van Sommeren Daan D. J. A. , Caulfield C. P. , Woods Andrew W.
Published: April 2013

We describe new experiments to examine the buoyancy-induced turbulent mixing which results from the injection of a small constant volume flux of dense fluid at the top of a long narrow vertical tank with square cross-section, in which a steady laminar upward flow of less dense fluid is present. To conserve volume of fluid in the tank, fluid leaves the tank through two small openings near the top of the tank. Dense source fluid vigorously mixes with the less dense fluid of the upward flow, such that a dense mixing region of turbulent fluid propagates downwards during the transient mixing phase of the experiment. Eventually, the transport of dense fluid associated with the buoyancy-induced turbulent flow is balanced by the transport of less-dense fluid associated with the steady upward flow, such that the mixing region evolves into a layer of finite extent which stays approximately constant in height during a statistically steady mixing phase of the experiment. With an ideal source of downward constant buoyancy flux ${B}_{s} $ at the top of the tank, tank width $d$, and speed of the upward flow ${u}_{u} $, we perform experiments with Froude numbers $\mathit{Fr}= {u}_{u} {d}^{1/ 3} / { B}_{s}^{1/ 3} $ ranging between $O(0. 01)$ and $O(1)$. The steady-state height of the mixing region and the maximum reduced gravity as found near the source of buoyancy flux at the top of the tank increase with decreasing Froude number. For the experiments with intermediate values of the Froude number, we find that the steady-state mixing region is small enough to be contained in the experimental tank, but large enough not to be dominated by developing turbulence near the source of buoyancy flux. For these experiments, we show that the key buoyancy-induced turbulent mixing properties are not significantly affected by the upward flow. We use a dye-attenuation technique to obtain vertical profiles of the time- and horizontally averaged reduced gravity to show a good agreement between the experimental profiles and the solution of a nonlinear turbulent advection–diffusion equation during the steady mixing phase. Furthermore, we discuss the characteristic time scale of the transient mixing phase. We compare our experimental results with the numerical solution of a time-dependent nonlinear turbulent advection–diffusion equation during the transient mixing phase. We also describe three reduced models for the evolution of the reduced gravity distribution in the mixing region, and we demonstrate these models’ usefulness by comparison with our experimental results and the numerical solution of the time-dependent nonlinear turbulent advection–diffusion equation.
Experimental investigation of dissipation-element statistics in scalar fields of a jet flow
Authors: Gampert Markus , Schaefer Philip , Peters Norbert
Published: April 2013

We present a detailed experimental investigation of conditional statistics obtained from dissipation elements based on the passive scalar field$\theta $and its instantaneous scalar dissipation rate$\chi $. Using high-frequency planar Rayleigh scattering measurements of propane discharging as a round turbulent jet into coflowing carbon dioxide, we acquire with Taylor’s hypothesis a highly resolved three-dimensional field of the propane mass fraction$\theta $. The Reynolds number (based on nozzle diameter and jet exit velocity) varies between 3000 and 8600. The experimental results for the joint probability density of the scalar difference$ \mathrm{\Delta} \theta $and the length$l$of dissipation elements resembles those previously obtained from direct numerical simulations of Wang & Peters (J. Fluid Mech., vol. 554, 2006, pp. 457–475). In addition, the normalized marginal probability density function$\tilde {P} (\tilde {l} )$of the length of dissipation elements follows closely the theoretical model derived by Wang & Peters (J. Fluid Mech., vol. 608, 2008, pp. 113–138). We also find that the mean linear distance${l}_{m} $between two extreme points of an element is of the order of the scalar Taylor microscale${\lambda }_{u} $. Furthermore, the conditional mean$\langle \mathrm{\Delta} \theta \vert l\rangle $scales with Kolmogorov’s$1/ 3$power law. The investigation of the orientation of long dissipation elements in the jet flow reveals a preferential alignment, perpendicular to the streamwise direction for long elements, while the orientation of short elements is close to isotropic. Following an approach proposed by Kholmyansky & Tsinober (Phys. Lett. A, vol. 373, 2009, pp. 2364–2367), we finally investigate the probability density function of the scalar increment$\delta \theta $in the streamwise direction, when strong dissipative events are either retained in or excluded from the measurement volume. In the present study, however, these events are related to maximum points of the scalar dissipation rate$\chi $together with their local extent. When these regions are excluded from the scalar field, we observe a tendency of the probability density function$P(\delta \theta (r))$towards a Gaussian bell-shaped curve.
OPTIMAL PLANNING OF COCOA CLONAL SELECTION PROGRAMMES
Authors: OWUSU-ANSAH F. , CURNOW R. N. , ADU-AMPOMAH Y.
Published: April 2013

Data from three cocoa (Theobroma cacao) clonal selection trials are used to investigate the genetic and environmental components of variation in yield and the percentage of total pods affected by black pod disease (Phytophtorapod rot). Simulations based on these estimated components of variation are then used to discuss the best choice in future of numbers of clones, replicates and years of harvest to maximise selection advances in the traits measured. The three main conclusions are the need to increase the number of clones at the expense of the number of replicates of each clone, the diminishing returns from additional years of harvesting and the importance of widening the genetic base of the clones chosen to be tested.
A REPLY TO ABDELMAJID HANNOUM
Authors: Silverstein Paul
Published: April 2013

I regret that Professor Hannoum believes I mischaracterized his argument. By their nature, book reviews synthesize and condense; they cannot capture all the nuances authors may have wished to convey in their larger work. For all of our shared interests and engagements, Professor Hannoum and I clearly disagree on the contours of the academic historiography of colonial Algeria, on the lasting influence of colonialism as a (violent) project of world-making, on the interplay of empirical description and theoretical reflection, and on the role of anthropological research in articulating a political critique of the present. Professor Hannoum's book was written as a polemic and thus invites argument. I encourage readers to examine his book and respond themselves.
Communicative focus on second language phonetic form: Teaching Japanese learners to perceive and produce English /ɹ/ without explicit instruction
Authors: SAITO KAZUYA
Published: April 2013

The current study examines in depth how two types of form-focused instruction (FFI), which are FFI with and without corrective feedback (CF), can facilitate second language speech perception and production of /ɹ/ by 49 Japanese learners in English as a Foreign Langage settings. FFI effectiveness was assessed via three outcome measures (perception, controlled production, and spontaneous production) and also according to two lexical contexts (trained and untrained items). Two experimental groups received 4 hr of FFI treatment to notice and practice the target feature of /ɹ/ (but without any explicit instruction) in meaningful discourse. A control group (n= 14) received comparable instruction in the absence of FFI. During FFI, the instructors provided CF only to students in the FFI + CF group (n= 18) by recasting their mispronunciations of /ɹ/, while no CF was provided to those in the FFI-only group (n= 17). Analyses of pre- and posttests showed that FFI itself can sufficiently promote the development of speech perception and production of /ɹ/ and the acquisitional value of CF in second language speech learning remains unclear. The results suggest that the beginner learners without much phonetic knowledge on how to repair their mispronunciation of /ɹ/ should be encouraged to learn the target sound only through FFI in a receptive mode without much pressure for modified output.
Memorialization, Memorabilia, and the Mediated Afterlife of Ada Reeve
Authors: Lipton Martina
Published: April 2013

This paper explores the differing levels of control over representations of Ada Reeve's mediated and ‘ghosted’ afterlife. Confessional memoirs that strategically frame the star persona for posterity provide her with the most immediate control. However, the star can become recruited to new assertions of cultural nationalism, which desire to claim coherent genealogies, public celebration, and commemoration of a star's afterlife. This, paired with nostalgic desires for past ‘golden ages’, also mediates strategic interests in her imbricated identity. Similarly, the star's mediated afterlife inevitably becomes susceptible to repositioning by theatre managements, the media, family, fans, and the public when their revisionist agendas make new assertions for the star's image after death in various immediate political and social contexts, and as communal encoded memory. Martina Lipton is Research Fellow (Australia) at the University of Warwick and Honorary Associate Lecturer at the University of Queensland. She has published several articles in Australasian Drama Studies, Contemporary Theatre Review, New Theatre Quarterly, and Popular Entertainment Studies on pantomime and popular theatre performers, and her paper ‘Localism and British Modern Pantomime’ is in A World of Popular Entertainments: an Edited Volume of Critical Essays (2012).
Legal Pluralism in the Pacific: Solomon Island's World War II Heritage
Authors: Forrest Craig , Corrin Jennifer
Published: April 2013

The country of Solomon Islands, like most Pacific island nations, has a legally pluralistic regime. That is, customary law operates in parallel with the common law, a legacy of Solomon Islands' colonial past. Legal pluralism raises significant difficulties, including in the way cultural heritage is protected and managed. To date, the courts have rarely been called on to deal with such issues, but in 2010 the High Court had to examine legislation designed to regulate the recovery and export of World War II relics. This seemingly innocuous case raised a number of issues concerning the rights of different stakeholders to this material. Moreover, it raised a foundational question as to whether these relics might be considered cultural heritage, and if so, just whose heritage it was. A consideration of this case and the legislation that applies to this heritage serves to illustrate some of the difficulties that arise in protecting cultural heritage within pluralistic legal systems.