bluuebunny/crossref_metadata_2025 huggingface dataset:
Stadt- und Raumplaner – zum Wandel eines Berufsbildes
Authors: Krau Ingrid
Published: May 2014

The profession of spatial planners started in Germany in 1968 with its first belated planning-department apart from town-planning education within architectural faculties, shaping its thinking in contrast to architectural-led town-planning. Regarding the career of 45 years of planner-education, we find fundamental transformations of the planners’ thinking, leading from a rather autonomous start-off apart from established planning, ending up in the acceptance of the predominance of self-regulating markets and governance structures. Led by incremental thinking and negotiation, spatial planners have separated themselves from physical planning as well as from planning-theory which could guideline their thinking, renouncing goal-led development and formal plans; on the other hand town planners have restricted themselves to informal physical plans with little power of implementation. Especially since the financial crisis after 2000 planning gives way to neoliberal arrangements, resulting in growing imbalance and fails in spatial development. So the demand of sovereign thinking to crosscounter this development is increasing. This leads to a challenge for planning-departments to reconsider their educational ambitions and to enlarge knowledge and skills by transdisciplinary cooperation to develop answers to the unsolved questions beyond the old separation of disciplines.
SUR LES COMPOSANTES CONNEXES D’UNE FAMILLE D’ESPACES ANALYTIQUES -ADIQUES
Authors: POINEAU JÉRÔME
Published: May 2014

Soit $X=\mathcal{M}(\mathscr{A})$ un espace affinoïde et soient $f,g\in \mathscr{A}$. Nous étudions les ensembles de composantes connexes des espaces définis par une inégalité de la forme $|f|\le r\, |g|$, avec $r\ge 0$. Nous montrons qu’il existe une partition finie de $\mathbf{R}_{+}$ en intervalles sur lesquels ces ensembles sont canoniquement en bijection et que les bornes de ces intervalles appartiennent à $\sqrt{\rho (\mathscr{A})}$.
Applicability and failure of the flux-gradient laws in double-diffusive convection
Authors: Radko Timour
Published: May 2014

Double-diffusive flux-gradient laws are commonly used to describe the development of large-scale structures driven by salt fingers – thermohaline staircases, collective instability waves and intrusions. The flux-gradient model assumes that the vertical transport is uniquely determined by the local background temperature and salinity gradients. While flux-gradient laws adequately capture mixing characteristics on scales that greatly exceed those of primary double-diffusive instabilities, their accuracy rapidly deteriorates when the scale separation between primary and secondary instabilities is reduced. This study examines conditions for the breakdown of the flux-gradient laws using a combination of analytical arguments and direct numerical simulations. The applicability (failure) of the flux-gradient laws at large (small) scales is illustrated through the example of layering instability, which results in the spontaneous formation of thermohaline staircases from uniform temperature and salinity gradients. Our inquiry is focused on the properties of the ‘point-of-failure’ scale ($\def \xmlpi #1{}\def \mathsfbi #1{\boldsymbol {\mathsf {#1}}}\let \le =\leqslant \let \leq =\leqslant \let \ge =\geqslant \let \geq =\geqslant \def \Pr {\mathit {Pr}}\def \Fr {\mathit {Fr}}\def \Rey {\mathit {Re}}H_{pof}$) at which the vertical transport becomes significantly affected by the non-uniformity of the background stratification. It is hypothesized that$H_{pof} $can control some key characteristics of secondary double-diffusive phenomena, such as the thickness of high-gradient interfaces in thermohaline staircases. A more general parametrization of the vertical transport – the flux-gradient-aberrancy law – is proposed, which includes the selective damping of relatively short wavelengths that are inadequately represented by the flux-gradient models. The new formulation is free from the unphysical behaviour of the flux-gradient laws at small scales (e.g. the ultraviolet catastrophe) and can be readily implemented in theoretical and large-scale numerical models of double-diffusive convection.
Effect of adiposity, season, diet and calcium or vitamin D supplementation on the vitamin D status of healthy urban African and Asian-Indian adults
Authors: George Jaya A. , Norris Shane A. , van Deventer Hendrick E. , Pettifor John M. , Crowther Nigel J.
Published: May 2014

Vitamin D deficiency has been implicated in the aetiology of infectious diseases and metabolic syndrome. These diseases are prevalent in the African and Asian-Indian populations of South Africa; however, there is limited data on 25-hydroxyvitamin D (25(OH)D) concentrations in these populations. The aim of the present study was to assess the vitamin D status and its predictors in healthy adults in Johannesburg. We assessed the vitamin D status of 730 adult African and Asian-Indian subjects residing in Johannesburg. The contributions of sun exposure, season, dietary intake of Ca and vitamin D, total body fat and body fat distribution to 25(OH)D concentrations were assessed. The concentrations of 25(OH)D were measured by HPLC. The contribution of 25(OH)D3to total 25(OH)D concentrations was assessed. The mean age of the subjects was 42·6 (sd13·1) years (range: 18–65). Concentrations of 25(OH)D < 30 nmol/l were found in 28·6 % of the Asian-Indian subjects in comparison with 5·1 % of the African subjects (P< 0·0001). Parathyroid hormone (PTH) concentrations were negatively associated with 25(OH)D concentrations, while season and sun exposure were positive predictors explaining 16 % of the variance in 25(OH)D concentrations (P< 0·0001) in the African subjects. In the Asian-Indian subjects, PTH concentrations were negatively associated with 25(OH)D concentrations, while male sex, season and Ca supplementation were positive predictors and explained 17 % of the variance in 25(OH)D concentrations (P< 0·0001). In the multivariate regression analysis, neither total body fat nor body fat distribution was predictive of 25(OH)D concentrations in either group. In conclusion, factors such as sun exposure, dietary supplement use and ethnicity are important determinants of plasma 25(OH)D concentrations.
Short-term obesity results in detrimental metabolic and cardiovascular changes that may not be reversed with weight loss in an obese dog model
Authors: Adolphe Jennifer L. , Silver Tawni I. , Childs Helene , Drew Murray D. , Weber Lynn P.
Published: May 2014

The time course of metabolic and cardiovascular changes with weight gain and subsequent weight loss has not been elucidated. The goal of the present study was to determine how weight gain, weight loss and altered body fat distribution affected metabolic and cardiovascular changes in an obese dog model. Testing was performed when the dogs were lean (scores 4–5 on a nine-point scale), afterad libitumfeeding for 12 and 32 weeks to promote obesity (>5 score), and after weight loss. Measurements included serum glucose and insulin, plasma leptin, adiponectin and C-reactive protein, echocardiography, flow-mediated dilation and blood pressure. Body fat distribution was assessed by computed tomography. Fasting serum glucose concentrations increased significantly with obesity (P< 0·05). Heart rate increased by 22 (se5) bpm after 12 weeks of obesity (P= 0·003). Systolic left ventricular free wall thickness increased after 12 weeks of obesity (P= 0·002), but decreased after weight loss compared with that observed in the lean phase (P= 0·03). Ventricular free wall thickness was more strongly correlated with visceral fat (r0·6,P= 0·001) than with total body fat (r0·4,P= 0·03) and was not significantly correlated with subcutaneous body fat (r0·3,P= 0·1). The present study provides evidence that metabolic and cardiovascular alterations occur within only 12 weeks of obesity in an obese dog model and are strongly predicted by visceral fat. These results emphasise the importance of obesity prevention, as weight loss did not result in the return of all metabolic indicators to their normal levels. Moreover, systolic cardiac muscle thickness was reduced after weight loss compared with the pre-obesity levels, suggesting possible acute adverse cardiovascular effects.
Dietary methionine availability affects the main factors involved in muscle protein turnover in rainbow trout (Oncorhynchus mykiss)
Authors: Belghit Ikram , Skiba-Cassy Sandrine , Geurden Inge , Dias Karine , Surget Anne , Kaushik Sadasivam , Panserat Stéphane , Seiliez Iban
Published: May 2014

Methionine is a limiting essential amino acid in most plant-based ingredients of fish feed. In the present study, we aimed to determine the effect of dietary methionine concentrations on several main factors involved in the regulation of mRNA translation and the two major proteolytic pathways (ubiquitin–proteasome and autophagy-lysosomal) in the white muscle of rainbow trout (Oncorhynchus mykiss). The fish were fed for 6 weeks one of the three isonitrogenous diets providing three different methionine concentrations (deficient (DEF), adequate (ADQ) and excess (EXC)). At the end of the experiment, the fish fed the DEF diet had a significantly lower body weight and feed efficiency compared with those fed the EXC and ADQ diets. This reduction in the growth of fish fed the DEF diet was accompanied by a decrease in the activation of the translation initiation factors ribosomal protein S6 and eIF2α. The levels of the main autophagy-related markers (LC3-II and beclin 1) as well as the expression of several autophagy genes (atg4b, atg12 l, Uvrag, SQSTM1, Mul1 and Bnip3) were higher in the white muscle of fish fed the DEF diet. Similarly, the mRNA levels of several proteasome-related genes (Fbx32, MuRF2, MuRF3, ZNF216 and Trim32) were significantly up-regulated by methionine limitation. Together, these results extend our understanding of mechanisms regulating the reduction of muscle growth induced by dietary methionine deficiency, providing valuable information on the biomarkers of the effects of low-fishmeal diets.
Combined effects of electronic trapping and non-thermal electrons on the expansion of laser produced plasma into vacuum
Authors: Bara Djemai , Djebli Mourad , Bennaceur-Doumaz Djamila
Published: May 2014

In this work, the effect of electron trapping on the self-similar expansion of electron-ion laser plasma into vacuum, combined with the effect of non-thermal (energetic) electrons is studied. For this, a mono-dimensional, non-relativistic model where the ions are cold and governed by fluid equations is used. In the approximation of quasi-neutrality of charge, the obtained self-similar solution shows that for ion (plasma) behavior, the presence of an important number of non-energetic trapped electrons in the plasma potential wells has the effect of slowing down the expansion, whereas the phenomenon of presence of energetic electrons makes the influence of trapping effect on the self-similar expansion very weak even in the case of a very small number of energetic electrons. This study is of interest in the context of the investigation of mono-energetic ion beams from intense laser interactions with plasmas.
Time-Resolved Spectra from Millivolt EELS Data
Authors: Li Chufeng , Subramanian Ganesh , Spence John C.H.
Published: May 2014

The millivolt energy resolution now obtainable in electron energy-loss spectra (EELS) on the latest monochromated scanning transmission electron microscope corresponds, via the uncertainty principle, to a time range of 414 fs (for 10 meV resolution), and a time resolution of 0.138 fs (for energy range of 30 eV). (Thus, the width of an EELS peak is inversely related to the lifetime of an excitation.) This compares favorably with the latest X-ray free electron lasers. The time evolution of a Drude–Lorentz oscillator may be obtained from an EELS using logarithmic deconvolution followed by Kramers–Kronig analysis to extract the frequency-dependent dielectric function, and a final Fourier transform from frequency to time domain. This time-dependent dielectric function was interpreted as the impulse response of electrons, phonons, or ions based on the Drude–Lorentz theory. The time evolution of electronic oscillators from ice and protein, extracted from low resolution experimental data, were compared. Using higher energy resolution data we have also extracted the time-resolved spectra from excitons in an alkali halide, BaF2. Despite the small scanning transmission electron microscope probe size, delocalization limits the spatial resolution to about 50 nm, which is, nevertheless, better than the millimeter resolution of infrared absorption spectroscopy or Raman spectroscopy.
The wasps, bees and ants (Insecta: Vespida=Hymenoptera) from the Insect Limestone (Late Eocene) of the Isle of Wight, UK
Authors: Antropov Alexander V. , Belokobylskij Sergey A. , Compton Stephen G. , Dlussky Gennady M. , Khalaim Andrey I. , Kolyada Victor A. , Kozlov Mikhail A. , Perfilieva Ksenia S. , Rasnitsyn Alexandr P.
Published: May 2014

The types and undescribed material of the hymenopteran fossils of the Insect Bed of the Bembridge Marls from the Isle of Wight (UK) are critically revised and studied. A total of 1460 fossils are recorded and attributed to 20 families: Gasteruptiidae s.l. (1); Proctotrupidae (3); Diapriidae (24); Cynipidae (7); Figitidae (6); Pteromalidae (1); Agaonidae (3); Scelionidae (12); Platygastridae (2); Ichneumonidae (32); Braconidae (75); Bethylidae (3); Crabronidae (2); Sphecidae (1); Apidae (2); Scoliidae (1); Tiphiidae (2); Vespidae (4); and Formicidae (1220). Described as new are 51 species, 13 genera, two tribes and two subfamilies. Minimum number of species recorded (either as described species or representing higher taxa with no described species in the assemblage) is 118. The composition of the hymenopteran assemblage is most similar to that of Baltic amber and indicative of a well forested territory, as well as of a humid, equable (aseasonal but not very hot) climate, more typically equable than in the Baltic amber source area, judging from the absence of Aphidiinae and scarcity of aphids.
Glücksspielbezogene Probleme unter Jugendlichen
Authors: Hayer Tobias , Meyer Gerhard , Petermann Franz
Published: May 2014

Kommerzielle Glücksspielangebote und selbstorganisierte Spiele um Geld repräsentieren integrale Bestandteile der Lebenswirklichkeit vieler Heranwachsender. In diesem Zusammenhang machen internationale wie nationale Befunde in konsistenter Weise darauf aufmerksam, dass in der Entwicklungsphase des Jugendalters ein erhöhtes Risiko besteht, glücksspielbezogene Probleme zu entwickeln. Allerdings mangelt es an testtheoretisch abgesicherten, jugendgerechten Verfahren zur Bestimmung eines problematischen Spielverhaltens. Daher muss letztendlich offen bleiben, ob diese Form jugendlichen Problemverhaltens überhaupt angemessen und zielgerichtet erfasst wird, oder ob es sich hierbei (zumindest partiell) um einen Messartefakt handelt. Ein Ziel zukünftiger Forschungen ist es folglich, ein Screening-Instrument zu entwickeln und zu validieren.
Initiating, Maintaining, or Breaking Up?
Authors: Menegatti Michela , Rubini Monica
Published: May 2014

Two studies examined whether individuals vary the level of abstraction of messages composed to achieve the relational goals of initiating, maintaining, and ending a romantic relationships when the goal of communication was self-disclosure or persuading one’s partner. Study 1 showed that abstract language was preferred to disclose thoughts and feelings about initiating a romantic relationship or to persuade the partner to consolidate a long-term one. Study 2 revealed that participants used abstract terms to persuade the partner to continue a problematic relationship and to disclose their thoughts on ending it. These results show that language abstraction is a flexible means to handle individuals’ goals and influence the course of romantic relationships.
Engineering of Hollow Mesoporous Silica Nanoparticles for Remarkably Enhanced Tumor Active Targeting Efficacy
Authors: Chen Feng , Hong Hao , Shi Sixiang , Goel Shreya , Valdovinos Hector F. , Hernandez Reinier , Theuer Charles P. , Barnhart Todd E. , Cai Weibo
Published: May 2014

Hollow mesoporous silica nanoparticle (HMSN) has recently gained increasing interests due to their tremendous potential as an attractive nano-platform for cancer imaging and therapy. However, possibly due to the lack of efficient in vivo targeting strategy and well-developed surface engineering techniques, engineering of HMSN for in vivo active tumor targeting, quantitative tumor uptake assessment, multimodality imaging, biodistribution and enhanced drug delivery have not been achieved to date. Here, we report the in vivo tumor targeted positron emission tomography (PET)/near-infrared fluorescence (NIRF) dual-modality imaging and enhanced drug delivery of HMSN using a generally applicable surface engineering technique. Systematic in vitro and in vivo studies have been performed to investigate the stability, tumor targeting efficacy and specificity, biodistribution and drug delivery capability of well-functionalized HMSN nano-conjugates. The highest uptake of TRC105 (which binds to CD105 on tumor neovasculature) conjugated HMSN in the 4T1 murine breast cancer model was ~10%ID/g, 3 times higher than that of the non-targeted group, making surface engineered HMSN a highly attractive drug delivery nano-platform for future cancer theranostics.
Evidence of horizontal transfer of non-autonomous Lep1 Helitrons facilitated by host-parasite interactions
Authors: Guo Xuezhu , Gao Jingkun , Li Fei , Wang Jianjun
Published: May 2014

Horizontal transfer (HT) of transposable elements has been recognized to be a major force driving genomic variation and biological innovation of eukaryotic organisms. However, the mechanisms of HT in eukaryotes remain poorly appreciated. The non-autonomous Helitron family, Lep1, has been found to be widespread in lepidopteran species and showed little interspecific sequence similarity of acquired sequences at 3′ end, which makes Lep1 a good candidate for the study of HT. In this study, we describe the Lep1-like elements in multiple non-lepidopteran species, including two aphids, Acyrthosiphon pisum and Aphis gossypii, two parasitoid wasps, Cotesia vestalis and Copidosoma floridanum, one beetle, Anoplophora glabripennis, as well as two bracoviruses in parasitoid wasps and one intracellular microsporidia parasite, Nosema bombycis. The patchy distribution and high sequence similarity of Lep1-like elements among distantly related lineages as well as incongruence of Lep1-like elements and host phylogeny suggest the occurrence of HT. Remarkably, the acquired sequences of both NbLep1 from N. bombycis and CfLep1 from C. floridanum showed over 90% identity with their lepidopteran host Lep1. Thus, our study provides evidence of HT facilitated by host-parasite interactions. Furthermore, in the context of these data, we discuss the putative directions and vectors of HT of Lep1 Helitrons.
Complex organic molecules along the accretion flow in isolated and externally irradiated protoplanetary disks
Authors: Walsh Catherine , Herbst Eric , Nomura Hideko , Millar T. J. , Weaver Susanna Widicus
Published: May 2014

The birth environment of the Sun will have influenced the physical and chemical structure of the pre-solar nebula, including the attainable chemical complexity reached in the disk, important for prebiotic chemistry. The formation and distribution of complex organic molecules (COMs) in a disk around a T Tauri star is investigated for two scenarios: (i) an isolated disk, and (ii) a disk irradiated externally by a nearby massive star. The chemistry is calculated along the accretion flow from the outer disk inwards using a comprehensive network which includes gas-phase reactions, gas-grain interactions, and thermal grain-surface chemistry. Two simulations are performed, one beginning with complex ices and one with simple ices only. For the isolated disk, COMs are transported without major chemical alteration into the inner disk where they thermally desorb into the gas reaching an abundance representative of the initial assumed ice abundance. For simple ices, COMs can efficiently form on grain surfaces under the conditions in the outer disk. Gas-phase COMs are released into the molecular layerviaphotodesorption. For the irradiated disk, complex ices are also transported inwards; however, they undergo thermal processing caused by the warmer conditions in the irradiated disk which tends to reduce their abundance along the accretion flow. For simple ices, grain-surface chemistry cannot efficiently synthesise COMs in the outer disk because the necessary grain-surface radicals, which tend to be particularly volatile, are not sufficiently abundant on the grain surfaces. Gas-phase COMs are formed in the inner region of the irradiated diskviagas-phase chemistry induced by the desorption of strongly bound molecules such as methanol; hence, the abundances are not representative of the initial molecular abundances injected into the outer disk. These results suggest that the composition of comets formed in isolated disks may differ from those formed in externally irradiated disks with the latter composed of more simple ices.
Mesoporous silica SBA-15 functionalized with phosphonate derivatives for uranium uptake
Authors: Wang Yu-Long , Zhu Lu , Guo Bo-Long , Chen Su-Wen , Wu Wang-Suo
Published: May 2014

Good selective sorption ability of SBA-15-PA for U(VI).
Quantitative analysis of fourteen synthetic dyes in jelly and gummy candy by ultra performance liquid chromatography
Authors: Yang Yi , Zhang Jing , Shao Bing
Published: May 2014

An analytical method was developed for the simultaneous determination of 14 dyes in jelly and gummy candy using ultra performance liquid chromatography with a photodiode array detector.
Adsorption of water on graphene/Ru(0001)—an experimental ultra-high vacuum study
Authors: Chakradhar A. , Burghaus U.
Published: May 2014

The intrinsic wetting properties of graphene/Ru(0001) were characterized at ultra-high vacuum conditions.
Intermolecular hydrogen transfer and solubility tuning in multi-component molecular crystals of the API piroxicam
Authors: Thomas Lynne H. , Klapwijk Anneke R. , Wales Craig , Wilson Chick C.
Published: May 2014

Twelve multi-component molecular crystals of the active pharmaceutical ingredient (API) piroxicam (PX) are described contrasting those with basic N-heterocycles with those formed with strong haloanilic acids. The effect on the solubility of this API is discussed, with evidence of enhanced solubility in the multi-component crystals formed.
Diversity of transition pathways in the course of crystallization into ice VII
Authors: Mochizuki Kenji , Himoto Kazuhiro , Matsumoto Masakazu
Published: May 2014

A new metastable ice phase is discovered in the freezing pathway into ice VII in accord with Ostwald's step rule.
Enhanced photoelectrochemical water-splitting performance of semiconductors by surface passivation layers
Authors: Liu Rui , Zheng Zhi , Spurgeon Joshua , Yang Xiaogang
Published: May 2014

This review paper summarized recent studies on improving the efficiency of semiconductor-based solar water-splitting devices by introducing surface passivation layers.
Rapid, low-cost and instrument-free CD4+ cell counting for HIV diagnostics in resource-poor settings
Authors: Glynn Macdara T. , Kinahan David J. , Ducrée Jens
Published: May 2014

We present a low-cost Lab-on-a-Chip option for cheap HIV diagnostics using whole blood, operating largely instrument-free, with rapid time-to-answer.
A computational mechanistic study of pH-dependent alcohol dehydrogenation catalyzed by a novel [C,N] or [C,C] cyclometalated Cp*Ir complex in aqueous solution
Authors: Zhang Dan-Dan , Chen Xian-Kai , Liu Hui-Ling , Huang Xu-Ri
Published: May 2014

Our results have elucidated the impressive performance of a catalyst in alcohol dehydrogenation in aqueous solution by tuning the pH value.
Magnetic control of electrochemical processes at electrode surface using iron-rich graphene materials with dual functionality
Authors: Lim Chee Shan , Ambrosi Adriano , Sofer Zdeněk , Pumera Martin
Published: May 2014

On-demand control of huge importance for electrochemical sensing & energy applications. A magnetically-switching method which reversibly controls the electrochemical reactivity is shown.
Structural and bonding properties of small TiGen− (n = 2–6) clusters: photoelectron spectroscopy and density functional calculations
Authors: Deng Xiao-Jiao , Kong Xiang-Yu , Xu Xi-Ling , Xu Hong-Guang , Zheng Wei-Jun
Published: May 2014

The structures of small TiGen− clusters can be considered as Ti-substituted Gen+1 or Ti-capped Gen clusters.
Swelling enhancement of polyelectrolyte brushes induced by external ions
Authors: Chu Xiao , Yang Jingfa , Liu Guangming , Zhao Jiang
Published: May 2014

The swelling of permanently charged polyelectrolyte brushes is discovered to be enhanced by the introduction of external salt at moderate concentrations, investigated by QCM-D and ellipsometry
Phase segregation in bio-inspired multi-component vesicles encompassing double tail phospholipid species
Authors: Aydin Fikret , Ludford Paul , Dutt Meenakshi
Published: May 2014

The effect of phase segregation and shape transformation on the interfacial tension of bio-inspired binary phospholipid vesicles.
Influence of carbon pore size on the discharge capacity of Li–O2batteries
Authors: Ding Ning , Chien Sheau Wei , Hor T. S. Andy , Lum Regina , Zong Yun , Liu Zhaolin
Published: May 2014

A direct correlation between carbon pore size and cell capacity has been proposed based on the results obtained from a series of intentionally designed and synthesized porous carbons with uniform pore sizes in the range from 20 to 100 nm.
Chiral-nematic liquid crystals as one dimensional photonic materials in optical sensors
Authors: Mulder D. J. , Schenning A. P. H. J. , Bastiaansen C. W. M.
Published: May 2014

Current developments in the field of thermotropic chiral-nematic liquid crystals as sensors are discussed.
Nonorthogonal molecular orbital method: Single-determinant theory
Authors: Watanabe Yoshihiro , Matsuoka Osamu
Published: May 2014

Using the variational principle, we have derived a variant of the Adams–Gilbert equation for nonorthogonal orbitals of a single-determinant wave function, which we name the modified Adams–Gilbert equation. If we divide the molecular system into several subsystems, such as bonds, lone pairs, and residues, we can solve the equations for the subsystems one by one. Thus, this procedure has linear scaling. We have presented a practical procedure for solving the equations that is also applicable to macromolecular calculations. The numerical examples show that the procedure yields, with reasonable effort, results comparable with those of the Hartree–Fock–Roothaan method for orthogonal orbitals. To resolve the convergence difficulty in the self-consistent-field iterations, we have found that virtual molecular-orbital shifts are very effective.
Calculation of exact vibrational spectra for P2O and CH2NH using a phase space wavelet basis
Authors: Halverson Thomas , Poirier Bill
Published: May 2014

‘‘Exact” quantum dynamics calculations of vibrational spectra are performed for two molecular systems of widely varying dimensionality (P2O and CH2NH), using a momentum-symmetrized Gaussian basis. This basis has been previously shown to defeat exponential scaling of computational cost with system dimensionality. The calculations were performed using the new “SwitchBLADE” black-box code, which utilizes both dimensionally independent algorithms and massive parallelization to compute very large numbers of eigenstates for any fourth-order force field potential, in a single calculation. For both molecules considered here, many thousands of vibrationally excited states were computed, to at least an “intermediate” level of accuracy (tens of wavenumbers). Future modifications to increase the accuracy to “spectroscopic” levels, along with other potential future improvements of the new code, are also discussed.
Mode transition of a Hall thruster discharge plasma
Authors: Hara Kentaro , Sekerak Michael J. , Boyd Iain D. , Gallimore Alec D.
Published: May 2014

A Hall thruster is a cross-field plasma device used for spacecraft propulsion. An important unresolved issue in the development of Hall thrusters concerns the effect of discharge oscillations in the range of 10–30 kHz on their performance. The use of a high speed Langmuir probe system and ultra-fast imaging of the discharge plasma of a Hall thruster suggests that the discharge oscillation mode, often called the breathing mode, is strongly correlated to an axial global ionization mode. Stabilization of the global oscillation mode is achieved as the magnetic field is increased and azimuthally rotating spokes are observed. A hybrid-direct kinetic simulation that takes into account the transport of electronically excited atoms is used to model the discharge plasma of a Hall thruster. The predicted mode transition agrees with experiments in terms of the mean discharge current, the amplitude of discharge current oscillation, and the breathing mode frequency. It is observed that the stabilization of the global oscillation mode is associated with reduced electron transport that suppresses the ionization process inside the channel. As the Joule heating balances the other loss terms including the effects of wall loss and inelastic collisions, the ionization oscillation is damped, and the discharge oscillation stabilizes. A wide range of the stable operation is supported by the formation of a space charge saturated sheath that stabilizes the electron axial drift and balances the Joule heating as the magnetic field increases. Finally, it is indicated from the numerical results that there is a strong correlation between the emitted light intensity and the discharge current.
Coercivity enhancement in Dy-free Nd–Fe–B sintered magnets by using Pr-Cu alloy
Authors: Wan Fangming , Zhang Yinfeng , Han Jingzhi , Liu Shunquan , Liu Tao , Zhou Lei , Fu Jianbo , Zhou Dong , Zhang Xiaodong , Yang Jinbo , Yang Yingchang , Chen Jie , Deng Zhiwei
Published: May 2014

The grain boundary phase of Dy-free sintered Nd-Fe-B magnets is modified by using Pr68Cu32 eutectic alloy. The coercivity of the modified magnets reaches 21 kOe, which is the highest value in Dy-free Nd-Fe-B sintered magnets. Microstructural investigations show that a smooth and thick grain boundary layer is formed, and the content of the ferromagnetic elements in the grain boundary layer decreases from 65 at. % to 9 at. %. In addition, the mean grain size (4.5 μm) in the doped sintered magnets is smaller than that (6.5 μm) in the original sintered magnets. The modification in grain boundary and grain size reduces the magnetic interactions among grains and hinders nucleation of reversed magnetic domains, resulting in a coercivity enhancement.
Radiative damping and synchronization in a graphene-based terahertz emitter
Authors: Moskalenko A. S. , Mikhailov S. A.
Published: May 2014

We investigate the collective electron dynamics in a recently proposed graphene-based terahertz emitter under the influence of the radiative damping effect, which is included self-consistently in a molecular dynamics approach. We show that under appropriate conditions synchronization of the dynamics of single electrons takes place, leading to a rise of the oscillating component of the charge current. The synchronization time depends dramatically on the applied dc electric field and electron scattering rate and is roughly inversely proportional to the radiative damping rate that is determined by the carrier concentration and the geometrical parameters of the device. The emission spectra in the synchronized state, determined by the oscillating current component, are analyzed. The effective generation of higher harmonics for large values of the radiative damping strength is demonstrated.
Silver-epoxy microwave filters and thermalizers for millikelvin experiments
Authors: Scheller Christian P. , Heizmann Sarah , Bedner Kristine , Giss Dominic , Meschke Matthias , Zumbühl Dominik M. , Zimmerman Jeramy D. , Gossard Arthur C.
Published: May 2014

We present silver-epoxy filters combining excellent microwave attenuation with efficient wire thermalization, suitable for low temperature quantum transport experiments. Upon minimizing parasitic capacitances, the attenuation reaches ≥100 dB above ≈150 MHz and—when capacitors are added—already above ≈30 MHz. We measure the device electron temperature with a GaAs quantum dot and demonstrate excellent filter performance. Upon improving the sample holder and adding a second filtering stage, we obtain electron temperatures as low as 7.5 ± 0.2 mK in metallic Coulomb blockade thermometers.
Oxygen and nitrogen diffusion in α-hafnium from first principles
Authors: O'Hara Andrew , Demkov Alexander A.
Published: May 2014

We use a combination of density functional theory and multistate diffusion formalism to analyze the diffusion of oxygen and nitrogen in technologically important hafnium metal. Comparing the local density approximation and the Perdew-Burke-Ernzerhof version of the generalized gradient approximation, we find that a better description of the hafnium lattice in the latter results in the correct sequence of stable and transition states for oxygen interstitials leading to essentially quantitative agreement with experiment. For oxygen diffusion, we find an isotropic temperature-dependent diffusion coefficient of D=0.082e−2.04/kBTcm2s−1 utilizing interstitial sites with hexahedral and octahedral coordination. For the diffusivity of nitrogen, we find that an additional stable interstitial site, the crowdion site, exists and that the diffusion coefficient is D=0.15e−2.68/kBTcm2s−1. Our results also reproduce the experimental observation that nitrogen diffusivity is lower than that of oxygen in hafnium.
Inhibitive formation of nanocavities by introduction of Si atoms in Ge nanocrystals produced by ion implantation
Authors: Cai R. S. , Wang Y. Q. , Shang L. , Liu X. H. , Zhang Y. J. , Ross G. G. , Barba D.
Published: May 2014

Germanium nanocrystals (Ge-nc) were successfully synthesized by co-implantation of Si and Ge ions into a SiO2 film thermally grown on (100) Si substrate and fused silica (pure SiO2), respectively, followed by subsequent annealing at 1150 °C for 1 h. Transmission electron microscopy (TEM) examinations show that nanocavities only exist in the fused silica sample but not in the SiO2 film on a Si substrate. From the analysis of the high-resolution TEM images and electron energy-loss spectroscopy spectra, it is revealed that the absence of nanocavities in the SiO2 film/Si substrate is attributed to the presence of Si atoms inside the formed Ge-nc. Because the energy of Si-Ge bonds (301 kJ·mol−1) are greater than that of Ge-Ge bonds (264 kJ·mol−1), the introduction of the Si-Ge bonds inside the Ge-nc can inhibit the diffusion of Ge from the Ge-nc during the annealing process. However, for the fused silica sample, no crystalline Si-Ge bonds are detected within the Ge-nc, where strong Ge outdiffusion effects produce a great number of nanocavities. Our results can shed light on the formation mechanism of nanocavities and provide a good way to avoid nanocavities during the process of ion implantation.
Boron diffusion in nanocrystalline 3C-SiC
Authors: Schnabel Manuel , Weiss Charlotte , Canino Mariaconcetta , Rachow Thomas , Löper Philipp , Summonte Caterina , Mirabella Salvo , Janz Stefan , Wilshaw Peter R.
Published: May 2014

The diffusion of boron in nanocrystalline silicon carbide (nc-SiC) films with a grain size of 4–7 nm is studied using a poly-Si boron source. Diffusion is found to be much faster than in monocrystalline SiC as it takes place within the grain boundary (GB) network. Drive-in temperatures of 900–1000 °C are suitable for creating shallow boron profiles up to 100 nm deep, while 1100 °C is sufficient to flood the 200 nm thick films with boron. From the resulting plateau at 1100 °C a boron segregation coefficient of 28 between nc-SiC and the Si substrate, as well as a GB boron solubility limit of 0.2 nm−2 is determined. GB diffusion in the bulk of the films is Fickian and thermally activated with DGB(T)=(3.1−5.6)×107exp(−5.03±0.16  eV/kBT) cm2s−1. The activation energy is interpreted in terms of a trapping mechanism at dangling bonds. Higher boron concentrations are present at the nc-SiC surface and are attributed to immobilized boron.
Alternative current conduction mechanisms of organic-inorganic compound [N(CH3)3H]2CuCl4
Authors: Ben Bechir M. , Karoui K. , Tabellout M. , Guidara K. , Ben Rhaiem A.
Published: May 2014

The [N(CH3)3H]2CuCl4 single crystal has been analyzed by X-ray powder diffraction patterns, differential scanning calorimetry (DSC), and electrical impedance spectroscopy. [N(CH3)3H]2CuCl4 crystallizes at room temperature in the monoclinic system with P21/C space group. Three phase transitions at T1 = 226 K, T2 = 264 K, and T3 = 297 K have been evidenced by DSC measurements. The electrical technique was measured in the 10−1–107 Hz frequency range and 203–313 K temperature intervals. The frequency dependence of alternative current (AC) conductivity is interpreted in terms of Jonscher's law (developed). The AC electrical conduction in [N(CH3)3H]2CuCl4 compound is studied by two processes which can be attributed to a hopping transport mechanism: the correlated barrier hopping model in phases I, II, and III, the non-overlapping small polaron tunneling model in phase IV. The conduction mechanism is interpreted with the help of Elliot's theory, and the Elliot's parameters are found.
Application of cnidae composition in phylogenetic analyses of North Atlantic and Mediterranean dendrophylliid corals (Anthozoa : Scleractinia)
Authors: Martínez-Baraldés Irene , López-González Pablo J. , Megina César
Published: May 2014

Scleractinian corals are widely distributed in all oceans and at all bathymetric levels. Corals are among the most important bio-building organisms in marine ecosystems. The systematics of this hexacoral group is currently undergoing much change owing to studies that combine molecular analyses with morphological research on the calcareous skeletons. However, information from polyp anatomy has been widely ignored, and some aspects, such as the diversity and distribution of the cnidocysts, might help to obtain a better understanding of the relationships at different taxonomic levels. In this study, the cnidocysts of four species of the family Dendrophylliidae (Dendrophyllia ramea, D. cornigera, D. laboreli and Astroides calycularis) are analysed to evaluate the application of cnidae in phylogenetic analyses, and to complete our knowledge of cnidae composition (types, distribution and sizes) for these species. A discriminant analysis based on the cnidae of these species supports the usefulness of these structures. The obtained results indicate that additional morphological characters in scleractinian corals that may help to clarify their phylogenetic relationships can still be found.
A single amino acid polymorphism in the Drosophila melanogaster Dα1 (ALS) subunit enhances neonicotinoid efficacy at Dα1-chicken β2 hybrid nicotinic acetylcholine receptor expressed in Xenopus laevis oocytes
Authors: Ihara Makoto , Shimazu Naoya , Utsunomiya Mai , Akamatsu Miki , Sattelle David B , Matsuda Kazuhiko
Published: May 2014

Polymorphisms are sometimes observed in native insect nicotinic acetylcholine receptor (nAChR) subunits, which are important insecticide targets, yet little is known of their impact on insecticide actions. Here we investigated the effects of a polymorphism involving the substitution of histidine108 by leucine in the Drosophila melanogaster Dα1 subunit on the agonist actions of the neurotransmitter acetylcholine (ACh) and two commercial neonicotinoid insecticides (imidacloprid and clothianidin). There was no significant impact of the H108L substitution on either the ACh EC50, the concentration leading to a half maximal ACh response, or the maximum current amplitude in response at 10 μM ACh, of the Dα1-chicken β2 nAChR expressed in Xenopus laevis oocytes. However, the response amplitudes to imidacloprid and clothianidin were significantly enhanced, indicating a role of His108 in the selective interactions of Dα1 with these neonicotinoids.
Archetypal psychology and non-figurative painting
Authors: Maclagan David
Published: May 2014

Given that the idiom of archetypal psychology is emphatically figurative, how do we deal with non-figurative painting from this perspective? This paper focuses on the kind of abstract painting in which spontaneous, gestural marks create a ground where specific forms cannot be clearly distinguished (Jackson Pollock's ‘drip’ paintings being a well-known example). Such ‘chaotic’ paintings call into question the whole notion of what we mean by ‘image’. I relate these to Anton Ehrenzweig's concept of ‘inarticulate form’, as well as to some of James Hillman's ideas about aesthetic apprehension, and also draw on my own experience as an artist in creating a series called ‘The ground of All Being’.
Voicing concern and difference: from public spaces to common-places
Authors: Thévenot Laurent
Published: May 2014

This paper aims to clarify some of the contributions that so-called ‘pragmatic sociology’ [sociologie pragmatique] might make to political and cultural sociology. The appellation is commonly used to encompass a research current that has contributed to the revival of the French social sciences for nearly 40 years, in sociology, anthropology, political science but also institutional economics and economic sociology – specifically ‘Economie des conventions’: convention theory – and law, and that has lately reached an international audience. I shall concentrate here on the line of research that originated in the foundational model of conflicting orders of worth that Luc Boltanski and I developed and which I expanded into a sociology of engagements.
The multitude and localized protest: the example of the Quebec student strike
Authors: Fournier Philippe
Published: May 2014

The financial crisis and the ensuing budgetary cuts that have been imposed in many countries have sparked anti-austerity protests. One of the striking features of movements that self-identify as progressive is that they have directed the best part of their claims, efforts and discontent at state authorities. The reality of protest on the ground then seems to diverge from influential accounts of resistance such as Hardt and Negri’s, who point to its necessarily diffuse, transnational character. Although it suggests helpful ways to think about power, resistance and ethics on a transnational scale, Hardt and Negri's theoretical construction partly fails to capture the antagonisms and organizational forms that have emerged in the recent protest cycle. In order to remedy some of these weaknesses, the article borrows from social movement theory. It argues that the combination of Hardt and Negri's broader philosophical claims, themselves largely inspired by Italian autonomism, with a more sociological take on protest, can help us better identify the antagonisms and social forms pertaining to contemporary anti-austerity movements but also the organizational and strategic possibilities within local and national contexts. The results of this conversation are then applied to a specific struggle, the Quebec student strike.
Improving the public health sector in South Africa: eliciting public preferences using a discrete choice experiment
Authors: Honda Ayako , Ryan Mandy , van Niekerk Robert , McIntyre Diane
Published: May 2014

Background The introduction of national health insurance (NHI), aimed at achieving universal coverage, is the most important issue currently on the South African health policy agenda. Improvement in public sector health-care provision is crucial for the successful implementation of NHI as, regardless of whether health-care services become more affordable and available, if the quality of the services provided is not acceptable, people will not use the services. Although there has been criticism of the quality of public sector health services, limited research is available to identify what communities regard as the greatest problems with the services.

Methods A discrete choice experiment (DCE) was undertaken to elicit public preferences on key dimensions of quality of care when selecting public health facilities in South Africa. Qualitative methods were applied to establish attributes and levels for the DCE. To elicit preferences, interviews with community members were held in two South African provinces: 491 in Western Cape and 499 in Eastern Cape.

Results The availability of necessary medicine at health facilities has the greatest impact on the probability of attending public health facilities. Other clinical quality attributes (i.e. provision of expert advice and provision of a thorough examination) are more valued than non-clinical quality of care attributes (i.e. staff attitude, treatment by doctors or nurses, and waiting time). Treatment by a doctor was less valued than all other attributes.

Conclusion Communities are prepared to tolerate public sector health service characteristics such as a long waiting time, poor staff attitudes and lack of direct access to doctors if they receive the medicine they need, a thorough examination and a clear explanation of the diagnosis and prescribed treatment from health professionals. These findings prioritize issues that the South African government must address in order to meet their commitment to improve public sector health-care service provision.
Analysis of tetra- and hepta-nucleotides motifs promoting -1 ribosomal frameshifting in Escherichia coli
Authors: Sharma Virag , Prère Marie-Françoise , Canal Isabelle , Firth Andrew E. , Atkins John F. , Baranov Pavel V. , Fayet Olivier
Published: May 2014

Programmed ribosomal -1 frameshifting is a non-standard decoding process occurring when ribosomes encounter a signal embedded in the mRNA of certain eukaryotic and prokaryotic genes. This signal has a mandatory component, the frameshift motif: it is either a Z_ZZN tetramer or a X_XXZ_ZZN heptamer (where ZZZ and XXX are three identical nucleotides) allowing cognate or near-cognate repairing to the -1 frame of the A site or A and P sites tRNAs. Depending on the signal, the frameshifting frequency can vary over a wide range, from less than 1% to more than 50%. The present study combines experimental and bioinformatics approaches to carry out (i) a systematic analysis of the frameshift propensity of all possible motifs (16 Z_ZZN tetramers and 64 X_XXZ_ZZN heptamers) in Escherichia coli and (ii) the identification of genes potentially using this mode of expression amongst 36 Enterobacteriaceae genomes. While motif efficiency varies widely, a major distinctive rule of bacterial -1 frameshifting is that the most efficient motifs are those allowing cognate re-pairing of the A site tRNA from ZZN to ZZZ. The outcome of the genomic search is a set of 69 gene clusters, 59 of which constitute new candidates for functional utilization of -1 frameshifting.