bluuebunny/crossref_metadata_2025 huggingface dataset:
Efficient silicon quantum dots light emitting diodes with an inverted device structure
Authors: Yao Li , Yu Ting , Ba Lixiang , Meng Hu , Fang Xin , Wang Yilun , Li Lei , Rong Xin , Wang Suo , Wang Xinqiang , Ran Guangzhao , Pi Xiaodong , Qin Guogang
Published: November 2015

SiQDs with an average diameter of 2.6 ± 0.5 nm are used as the light emitting material in high-efficiency inverted structure light emitting diodes.
Cellular and molecular mechanisms of HGF/Met in the cardiovascular system
Authors: Gallo Simona , Sala Valentina , Gatti Stefano , Crepaldi Tiziana
Published: November 2015

Met tyrosine kinase receptor, also known as c-Met, is the HGF (hepatocyte growth factor) receptor. The HGF/Met pathway has a prominent role in cardiovascular remodelling after tissue injury. The present review provides a synopsis of the cellular and molecular mechanisms underlying the effects of HGF/Met in the heart and blood vessels. In vivo, HGF/Met function is particularly important for the protection of the heart in response to both acute and chronic insults, including ischaemic injury and doxorubicin-induced cardiotoxicity. Accordingly, conditional deletion of Met in cardiomyocytes results in impaired organ defence against oxidative stress. After ischaemic injury, activation of Met provides strong anti-apoptotic stimuli for cardiomyocytes through PI3K (phosphoinositide 3-kinase)/Akt and MAPK (mitogen-activated protein kinase) cascades. Recently, we found that HGF/Met is also important for autophagy regulation in cardiomyocytes via the mTOR (mammalian target of rapamycin) pathway. HGF/Met induces proliferation and migration of endothelial cells through Rac1 (Ras-related C3 botulinum toxin substrate 1) activation. In fibroblasts, HGF/Met antagonizes the actions of TGFβ1 (transforming growth factor β1) and AngII (angiotensin II), thus preventing fibrosis. Moreover, HGF/Met influences the inflammatory response of macrophages and the immune response of dendritic cells, indicating its protective function against atherosclerotic and autoimmune diseases. The HGF/Met axis also plays an important role in regulating self-renewal and myocardial regeneration through the enhancement of cardiac progenitor cells. HGF/Met has beneficial effects against myocardial infarction and endothelial dysfunction: the cellular and molecular mechanisms underlying repair function in the heart and blood vessels are common and include pro-angiogenic, anti-inflammatory and anti-fibrotic actions. Thus administration of HGF or HGF mimetics may represent a promising therapeutic agent for the treatment of both coronary and peripheral artery disease.
Collaborative Groups: Application of a Framework for Interprofessional Collaboration in a High School Setting
Authors: Tyszka Andrea Carr , DiLuzio Lynette
Published: November 2015

Interprofessional collaboration (IPC), also referred to as interdisciplinary collaboration, is defined in the social work literature as “an effective interpersonal process that facilitates the achievement of goals that cannot be reached when individual professionals act on their own” (Bronstein, 2003, p. 299). IPC is well documented in health care literature and is largely considered best practice in both clinical & educational settings. So much so that the World Health Organization (WHO) developed a Framework for Action on Interprofessional Education (WHO, 2010) and the Canadian Interprofessional Health Collaborative (CIHC) developed a National Interprofessional Competency Framework (CIHC, 2010). According to a systematic review of collaborative models for health and education professionals working in the school settings, models of IPC are described in research but not explicitly evaluated, and there remains a need for robust research in this area (Hillier, Civetta, & Pridham, 2010). This article describes the implementation of an IPC with high school aged students in a special education classroom. The following interconnecting domains from the Canadian National Interprofessional Competency Framework (CIHC, 2010) will be discussed and described:

Role Clarification

Patient/Client/Family/Community-Centered

Team Functioning

Collaborative Leadership

Interprofessional Communication

Interprofessional Conflict Resolution

Background considerations, benefits, and barriers will be reviewed also.
Saturation throughput analysis of IEEE 802.11ac TXOP sharing mode
Authors: Chung Chulho , Jung Yunho , Kim Jaeseok
Published: November 2015

A mathematical model to analyse the saturation throughput of IEEE 802.11ac medium access control (MAC) is proposed. The main contributions of the proposed model are the integration of the transmission opportunity (TXOP) sharing mode and the consideration of variable‐length MAC protocol data units, instead of a fixed‐length assumption. By using the model, accurate results (within 2% relative error) for the IEEE 802.11ac TXOP sharing mode are achieved.
Personnel recognition based on multistatic micro‐Doppler and singular value decomposition features
Authors: Fioranelli F. , Ritchie M. , Griffiths H.
Published: November 2015

The use of micro‐Doppler signatures experimentally collected by a multistatic radar system to recognise and classify different people walking is discussed. A suitable feature based on singular value decomposition of the spectrograms is proposed and tested with different types of classifiers. It is shown that high accuracy of between 97 and 99% can be achieved when multistatic data are used to perform the classification.
Angle‐based Y‐shaped chipless radio frequency identification tag
Authors: Feng Caixia , Chen Xinwei , Han Liping , Li Li , Han Guorui , Zhang Wenmei
Published: November 2015

This study presents a novel angle‐based chipless radio frequency identification tag. Its scatterer is designed to be Y‐shaped. It encodes data using the space angles between the arms of the Y‐shape and is identified by measuring the scattered field in two orthogonal polarisation directions. Even if it is rotated, the tag can be identified. In addition, the tag is excited with a circularly polarised wave. The cases excited with an elliptically polarised wave are also discussed. Finally, the proposed tag is realised and measured. The results indicate the realised tags operate in the frequency range 1.4–1.8 and 2.1–2.5 GHz for different codes. Every element can carry 8.1 bits of coding information. The identification errors are less than ±3.8°.
Stability improvement of matrix converter by digitally filtering the input voltages in stationary frame
Authors: Lei Jiaxing , Zhou Bo , Qin Xianhui , Bian Jinliang , Wei Jiadan
Published: November 2015

The constant power control strategy of matrix converter (MC), which is commonly adopted in practice to suppress input disturbances, could result in system instability and oscillations of source currents and input voltages. To stabilise the system, a novel control method is proposed in this study, which is based on filtering the input voltages in stationary frame with digital high‐pass filters of zero gain at the fundamental frequency. The filtered signals are injected to input currents so as to increase the input admittances for stability improvement. Since the filtered signals do not contain any fundamental frequency components, the proposed method would not affect the normal operation of MC. No matter the operation mode of MC is motoring or generating, the proposed method is always effective to improve system stability by adjusting the proportional coefficient and time constant of the digital filters. The feasibility and validity of the proposed method is verified by experimental results.
Reduction in number of devices for symmetrical and asymmetrical multilevel inverters
Authors: Gautam Shivam Prakash , Sahu Lalit Kumar , Gupta Shubhrata
Published: November 2015

Multilevel inverter (MLI) is receiving remarkable recognition due to its reduced voltage stress across the power switches and low total harmonic distortion in output voltage. However, MLI incorporates large number of semiconductor switches and hence increases its complexity. In this study, new structures of symmetrical and asymmetrical MLI are proposed. The proposed structures offer reduced number of controlled switches, power diodes, capacitors and DC sources as compared with classical and recently proposed topologies in the line. Reduction of switch count, driver circuit and DC voltage sources reduces the size, cost, complexity and enhances overall performance. Moreover significant reduction in voltage stress across the switches can be achieved. A comparative analysis of proposed topologies with the classical topology and recently published topologies has been made in terms of controlled switches, power diodes, driver circuit requirement, DC voltage sources and blocking voltage. Multi‐carrier pulse width modulation strategy is adopted for generating the switching pulses. The detailed simulation study of the proposed topology has been carried out using MATLAB/Simulink and feasibility of topology has been validated experimentally.
Linear generator‐based wave energy converter model with experimental verification and three loading strategies
Authors: Hong Yue , Eriksson Mikael , Castellucci Valeria , Boström Cecilia , Waters Rafael
Published: November 2015

Within the Lysekil wave energy research project at the Swedish west coast, more than ten Wave Energy Converters (WECs) prototypes have been developed and installed in an ocean based test site. Since 2006 various experiments have been conducted and the generated electricity was delivered to shore at a nearby island. While experiments are essential for the development of wave energy converters, theoretical studies and simulations are an important complement – not only in the search for advanced designs with higher efficiency, but also for improving the economic viability of the studied concepts. In this paper a WEC model is presented. The model consists of three subsystems: i) the hydrodynamic source, ii) the linear generator model, and iii) the electrical conversion system. After the validation with the experimental results at the research site, the generator model is connected to three passive load strategies – linear resistive load, passive rectification and resonance circuit. The paper focuses on analysing the operation of the model coupled with three load cases. The results prove that the WEC model correctly simulates the linear generator developed in the Lysekil Project. Moreover, the comparison among different load cases is made and discussed. The results gives an indication of the efficiency of energy production as well as the force ripples and resulting mechanical loads on the wave energy converters.
Intelligent energy exploitation from sewage
Authors: Truong Ngoc‐Hung , Krost Gerhard
Published: November 2015

Wastewater treatment plants are distinguished by considerable electricity consumption; on the other hand, organic contents of sewage allow for local energy recovery from, e.g. anaerobic digestion of sludge and subsequent use of resulting biogas in a combined heat and power unit. Supplementary incineration of dehydrated sludge in a local boiler feeding a steam turbine/generator set can provide another quantity of electricity and, at the same time, exonerates from further treatment/deposition of infectious sludge. Waste heat from both steam circuit and combustion engine can contribute to sludge drying, thus significantly increasing its heating value. Furthermore, large expanse and usual location remote of residential areas make sewage plants eligible for harvesting renewable energy. As innovative approach this study exposes that – even if all techniques considered for energy harvest in particular are state‐of‐the‐art – under proper combination/design and intelligent operation of devices and processes, sewage plants can be widely brought towards independence of external energy supply under reasonable economic conditions.
Off‐grid fast relevance vector machine algorithm for direction of arrival estimation
Authors: Lin Jincheng , Ma Xiaochuan , Yan Shefeng , Hao Chengpeng , Lin Geping
Published: November 2015

Direction of arrival (DOA) estimation is a basic and important problem in signal processing and has been widely applied. Its research has been advanced by the recently developed methods based on Bayesian compressive sensing (BCS). Among these methods, the ones combined with an off‐grid (OG) model have been proved to be more accurate than the on‐grid ones. However, the conventional BCS‐based methods have a disadvantage of the slow speed. In this study, a high‐efficiency iterative algorithm, based on the fast relevance vector machine and the OG model, is developed. This new approach applies to both the single‐ and multiple‐snapshot cases. Numerical simulations show that the proposed method estimates DOAs more accurately than the ℓ1‐penalisation method and computes more efficiently than the conventional BCS‐based methods. Finally, comparisons with state‐of‐the‐art methods and Cramer–Rao bound are also reported.
Multiple‐input–multiple‐output radar super‐resolution three‐dimensional imaging based on a dimension‐reduction compressive sensing
Authors: Hu Xiaowei , Tong Ningning , Zhang Yongshun , Hu Guoping , He Xingyu
Published: November 2015

A super‐resolution method for three‐dimensional (3D) imaging by combining a narrowband multiple‐input–multiple‐output (MIMO) radar and compressive sensing (CS) theory is presented. First, a narrowband bistatic MIMO radar with uniform linear transmit array and uniform rectangular receive array is proposed. After analysing the 3D echo signal, Kronecker CS (KCS) is introduced to solve the problem of low resolution in 3D image, which is caused by the limited transmit and receive array. Considering the great complexity of KCS in improving the 3D resolution jointly, a dimension‐reduction CS approach is presented to reduce its storage and computation burden. Furthermore, the restricted property of the dimension‐reduction dictionary is analysed to insure the accurate recovery. Finally, the effectiveness of the method is validated by the results of comparative simulations.
Preparation of multi‐walled carbon nanotubes and its application as flame retardant for polypropylene
Authors: Shen Yinlong , Gong Weiguang , Xu Yuanyuan , Zheng Baicun
Published: November 2015

NiO catalyst supported on Fe‐pillared montmorillonite (5–15 wt% Ni) was prepared via a simple conventional impregnation method. The physicochemical properties of the Ni catalyst were characterised by X‐ray diffraction, inductively coupled plasma‐atomic emission spectrometry and transmission electron microscopy. The Ni catalyst, together with organic montmorillonite (OMMT), was employed to prepare multi‐walled carbon nanotubes (MWCNTs) by using polypropylene (PP) as a precursor. An increase in Ni loading of the catalyst led to a significant increase in the yield of MWCNTs at the expense of a slight decline in quality of the obtained MWCNTs. Moreover, OMMT altered the degradation process of PP, which resulted in a much higher fraction of light hydrocarbons in degradation products. As such, a substantial increase in the yield of MWCNTs was attained. In addition, the obtained MWCNTs were used as flame retardant for PP, and significantly enhanced thermal stability and flame retardancy according to thermogravimetry analysis and cone data, respectively. PP/MWCNTs nanocomposite exhibited higher degradation temperature, longer ignition time, much lower heat release rate and smoke production rate. This work offers an efficient Ni catalyst to convert PP into MWCNTs which could be applied as flame retardant for polymers.
Facile synthesis method of poly(3,5‐dimethyoxyaniline) hollow microsphere through interfacial polymerisation approach using camphorsulfonic acid as the doping agent
Authors: Wang Xiaoqin , Xu Jinxin , Kong Zhenzhen , Xiong Shanxin , Li Zhufeng , Fu Jialun , Zhang Runlan , Gong Ming , Wu Bohua , Chu Jia
Published: November 2015

A facile synthesis method of poly(3,5‐dimethoxyaniline) (P(3,5‐DMA)) hollow microspheres was demonstrated by the interfacial polymerisation of 3,5‐dimethoxyaniline (3,5‐DMA) using camphorsulfonic acid (CSA) as the doping agent and soft template. The obtained P(3,5‐DMA) hollow microspheres possess narrow size distribution and uniform shape. A possible growth mechanism of the hollow microspheres was proposed through studying the change in morphologies of P(3,5‐DMA) at different reaction times. It is believed that the slow diffusion speed of monomer from the oil phase to the water phase in the interfacial polymerisation system controls the progress of polymerisation. Moreover, the interaction between amino group of the monomer and the sulfonic acid group of the doping agent micelle guides the formation of the hollow microspheres.
Characteristics of controllable‐shape well‐aligned zinc oxide nanorods synthesised by microwave‐assisted heating
Authors: Tsai M.K. , Huang W. , Hu S.Y. , Lee Yueh‐Chien , Lee J.W. , Lee M.H. , Shen J.L.
Published: November 2015

A microwave‐assisted heating method for growing well‐aligned zinc oxide (ZnO) nanorods on the ZnO/silicon (Si) substrate is developed. For ZnO nanorods growth, a thin ZnO seed layer was deposited on an Si substrate by sputtering technique. The ZnO nanorods grown on the ZnO/Si substrate were synthesised in aqueous solution mixed with zinc nitrate hexahydrate and hexamethylenetetramine (HMTA) under microwave heating. The scanning electron microscopy (SEM) images and X‐ray diffraction results exhibit that the ZnO nanorods with hexagonal phase, single crystalline, and highly oriented along (002) plane are obtained successfully. SEM images also show that the morphology and diameter of the synthesised ZnO nanorods can be controlled by adjusting the molar ratio of Zn(NO3)2 ·6H2O to HMTA. The Raman scattering results evidence the vertical well‐aligned ZnO nanrods with larger diameter are strain‐free. The investigations of the photoluminescence spectra suggest that the ultraviolet emission peak of the synthesised ZnO nanorods depending on its controllable diameter would be applicable for various nanodevice fabrications.
Measurement of ion species in high current ECR H+/D+ ion source for IFMIF (International Fusion Materials Irradiation Facility)
Authors: Shinto K. , Senée F. , Ayala J.-M. , Bolzon B. , Chauvin N. , Gobin R. , Ichimiya R. , Ihara A. , Ikeda Y. , Kasugai A. , Kitano T. , Kondo K. , Marqueta A. , Okumura Y. , Takahashi H. , Valette M.
Published: November 2015

Ion species ratio of high current positive hydrogen/deuterium ion beams extracted from an electron-cyclotron-resonance ion source for International Fusion Materials Irradiation Facility accelerator was measured by the Doppler shift Balmer-α line spectroscopy. The proton (H+) ratio at the middle of the low energy beam transport reached 80% at the hydrogen ion beam extraction of 100 keV/160 mA and the deuteron (D+) ratio reached 75% at the deuterium ion beam extraction of 100 keV/113 mA. It is found that the H+ ratio measured by the spectroscopy gives lower than that derived from the phase-space diagram measured by an Allison scanner type emittance monitor. The H+/D+ ratio estimated by the emittance monitor was more than 90% at those extraction currents.
Phase stabilization of VO2 thin films in high vacuum
Authors: Zhang Hai-Tian , Eaton Craig , Ye Hansheng , Engel-Herbert Roman
Published: November 2015

A new growth approach to stabilize VO2 on Al2O3 in high vacuum is reported by reducing vanadium oxytriisopropoxide (VTIP) with vanadium metal. Phase stabilization and surface wetting behavior were studied as a function of growth parameters. The flux balance of VTIP to V in combination with growth temperature was identified to be critical for the growth of high quality VO2 thin films. High V fluxes were required to suppress the island formation and to ensure a coalesced film, while too high V fluxes ultimately favored the formation of the undesired, epitaxially stabilized V2O3 phase. Careful optimization of growth temperature, VTIP to V ratio, and growth rate led to high quality single phase VO2 thin films with >3.5 orders of magnitude change in resistivity across the metal-to-insulator transition. This approach opens up another synthesis avenue to stabilize oxide thin films into desired phases.
Manipulating redox reaction during pulsed laser deposition
Authors: Wang Liuyong , Li Weiwei , Zhang Wenrui , Li Leigang , Zhao Run , Liu Qiong , Li Liang , Wang Haiyan , Yang Hao
Published: November 2015

Copper and copper oxide thin films have been synthesized on (001) SrTiO3 substrates using pulsed laser deposition. Three kinds of thin films can be achieved by changing deposition temperature and laser energy density: pure Cu, Cu:Cu2O composite, and pure Cu2O thin films. A phase diagram about the compositions of thin films has been represented and explained by redox reaction at the substrate surface during the deposition process. The present work represents a novel approach to further understand the surface reaction during deposition process and to fabricate oxide thin films with variable valence states using pulsed laser deposition.
Interlayer coupling effects on Schottky barrier in the arsenene-graphene van der Waals heterostructures
Authors: Xia Congxin , Xue Bin , Wang Tianxing , Peng Yuting , Jia Yu
Published: November 2015

The electronic characteristics of arsenene-graphene van der Waals (vdW) heterostructures are studied by using first-principles methods. The results show that a linear Dirac-like dispersion relation around the Fermi level can be quite well preserved in the vdW heterostructures. Moreover, the p-type Schottky barrier (0.18 eV) to n-type Schottky barrier (0.31 eV) transition occurs when the interlayer distance increases from 2.8 to 4.5 Å, which indicates that the Schottky barrier can be tuned effectively by the interlayer distance in the vdW heterostructures.
Heavy-ion injector based on an electron cyclotron ion source for the superconducting linear accelerator of the Rare Isotope Science Project
Authors: Hong In-Seok , Kim Yong-Hwan , Choi Bong-Hyuk , Choi Suk-Jin , Park Bum-Sik , Jin Hyun-Chang , Kim Hye-Jin , Heo Jeong-Il , Kim Deok-Min , Jang Ji-Ho
Published: November 2015

The injector for the main driver linear accelerator of the Rare Isotope Science Project in Korea, has been developed to allow heavy ions up to uranium to be delivered to the inflight fragmentation system. The critical components of the injector are the superconducting electron cyclotron resonance (ECR) ion sources, the radio frequency quadrupole (RFQ), and matching systems for low and medium energy beams. We have built superconducting magnets for the ECR ion source, and a prototype with one segment of the RFQ structure, with the aim of developing a design that can satisfy our specifications, demonstrate stable operation, and prove results to compare the design simulation.
Effects of substitution, pressure, and temperature on the phonon mode in layered-rocksalt-type Li(1−x)/2Ga(1−x)/2ZnxO (x = 0.036–0.515) alloys
Authors: Tan Lijie , Hu Qiwei , Lei Li , Jiang Xiaodong , Gao Shangpan , He Duanwei
Published: November 2015

ZnO-based semiconductor alloys, Li(1−x)/2Ga(1−x)/2ZnxO (x = 0.036–0.515) with a layered-rocksalt-type structure, have been prepared under high pressure. The composition, pressure, and temperature dependence of phonons have been studied by Raman spectroscopy. We observe two disorder-activated Raman (DAR) modes when the Zn composition x increases: a broad Raman peak at ca. 400 cm−1 and a left-shoulder peak at ca. 530 cm−1 on the low-frequency side of A1g mode at ca. 580 cm−1, which can be explained by reference to the phonon density of states for rocksalt-type ZnO. With the increase of the pressure and temperature, the left-shoulder DAR mode induced by substitution does not change at the same pace with the A1g mode at Brillouin-zone center. We find that ion substitution can be seen as a kind of chemical pressure, and the chemical pressure caused by internal substitution and the physical pressure caused by external compression have equivalent effects on the shortening of correlation length, the distortion of crystal lattice, and the change of atomic occupation.
Synthetic holography based on scanning microcavity
Authors: Di Donato A. , Farina M.
Published: November 2015

Synthetic optical holography (SOH) is an imaging technique, introduced in scanning microscopy to record amplitude and phase of a scattered field from a sample. In this paper, it is described a novel implementation of SOH through a lens-free low-coherence system, based on a scanning optical microcavity. This technique combines the low-coherence properties of the source with the mutual interference of scattered waves and the resonant behavior of a micro-cavity, in order to realize a high sensitive imaging system. Micro-cavity is compact and realized by approaching a cleaved optical fiber to the sample. The scanning system works in an open-loop configuration without the need for a reference wave, usually required in interferometric systems. Measurements were performed over calibration samples and a lateral resolution of about 1 μm is achieved by means of an optical fiber with a Numerical Aperture (NA) equal to 0.1 and a Mode Field Diameter (MDF) of 5.6 μm.
Plasmonic photocatalytic reactions enhanced by hot electrons in a one-dimensional quantum well
Authors: Huang H. J. , Liu B.–H. , Lin C.–T. , Su W. S.
Published: November 2015

The plasmonic endothermic oxidation of ammonium ions in a spinning disk reactor resulted in light energy transformation through quantum hot charge carriers (QHC), or quantum hot electrons, during a chemical reaction. It is demonstrated with a simple model that light of various intensities enhance the chemical oxidization of ammonium ions in water. It was further observed that light illumination, which induces the formation of plasmons on a platinum (Pt) thin film, provided higher processing efficiency compared with the reaction on a bare glass disk. These induced plasmons generate quantum hot electrons with increasing momentum and energy in the one-dimensional quantum well of a Pt thin film. The energy carried by the quantum hot electrons provided the energy needed to catalyze the chemical reaction. The results indicate that one-dimensional confinement in spherical coordinates (i.e., nanoparticles) is not necessary to provide an extra excited state for QHC generation; an 8 nm Pt thin film for one-dimensional confinement in Cartesian coordinates can also provide the extra excited state for the generation of QHC.
Seed micromorphology of central European Orobanche and Phelipanche (Orobanchaceae) in relation to preferred hosts and systematic implications
Authors: Piwowarczyk Renata
Published: November 2015

Holoparasitic genera within family Orobanchaceae are characterised by greatly reduced vegetative organs; therefore, seed micromorphology has proved to be a useful complementary taxonomic criterion. Seeds of 160 samples from 54 localities of 26 taxa of the Orobanche and Phelipanche genera occurring in central Europe, specifically from Poland, the Czech Republic, Austria and Slovakia, supplemented by samples from Spain, France and Ukraine, were investigated using scanning electron microscopy. Thirteen quantitative or qualitative morphological characters of seeds were analysed. The following three types of periclinal wall sculpture of seeds were identified: veined and fibrillar in Phelipanche; with oval or elliptic perforations (pitted) in almost all species of Orobanche; with outer periclinal wall smooth, granular or rugged (very rarely visibly pitted), impeding vision of the inner one, occurring only in O. gracilis Sm. and O. coerulescens Stephan in Willd. The influence of different hosts on the features of seeds of eight species is also presented, as well as relationships between seed morphology and taxonomic classification, including problematic taxa. The best diagnostic features include type of ornamentation of the periclinal wall, perforation diameter (in pitted sculpture), fibrillar diameter (in fibrillar sculpture) and width of anticlinal walls. Size and shape of the seeds and cells and the presence of median troughs are variable; however, these features can be helpful when using larger samples. The usefulness of micromorphological studies on seeds of Orobanche and Phelipanche is demonstrated.
Topological mechanics of gyroscopic metamaterials
Authors: Nash Lisa M. , Kleckner Dustin , Read Alismari , Vitelli Vincenzo , Turner Ari M. , Irvine William T. M.
Published: November 2015

Significance

We have built a new type of mechanical metamaterial: a “gyroscopic metamaterial” composed of rapidly spinning objects that are coupled to each other. At the edges of these materials, we find sound waves that are topologically protected (i.e. they cannot be scattered backward or into the bulk). These waves, which propagate in one direction only, are directly analogous to edge currents in quantum Hall systems. Through a mathematical model, we interpret the robustness of these edge waves in light of the subtle topological character of the bulk material. Crucially, these edge motions can be controlled by distorting the metamaterial lattice, opening new avenues for the control of sound in matter.
Universal spectrum of normal modes in low-temperature glasses
Authors: Franz Silvio , Parisi Giorgio , Urbani Pierfrancesco , Zamponi Francesco
Published: November 2015

Significance

The vibrational spectrum of glasses displays an anomalous excess of soft, low-frequency modes with respect to crystals. Such modes are responsible for many anomalies in thermodynamic and transport properties of low-temperature glasses. Many distinct proposals have been formulated to understand their origin but none of them results from the analytic solution of a microscopically grounded model. Here we solve analytically the spectrum of a simple model that belongs to the same universality class of glasses, and identify two distinct mechanisms that are responsible for the soft modes.
Superresolution imaging reveals structurally distinct periodic patterns of chromatin along pachytene chromosomes
Authors: Prakash Kirti , Fournier David , Redl Stefan , Best Gerrit , Borsos Máté , Tiwari Vijay K. , Tachibana-Konwalski Kikuë , Ketting René F. , Parekh Sapun H. , Cremer Christoph , Birk Udo J.
Published: November 2015

Significance

The structure of the pachytene chromosome is essential to understand how genetic recombination can happen during meiosis. Using single molecule localization microscopy with DNA staining, we show that chromatin is heavily constrained by defined periodic clusters along the synaptonemal complex (SC). Staining of various posttranslational histone modifications further reveals that the pachytene chromosome is associated with three distinct nanoscale compartments. Whereas chromatin associated with active transcription emanates both axially and radially in hair-like loop structures, the chromatin associated with repressed transcription follows periodic clusters close to the central axis of the SC. These findings suggest a model showing how chromatin and epigenetic modification patterns can be incorporated within the SC to shape the pachytene chromosome.
Dynamics of infinitely generated nicely expanding rational semigroups and the inducing method
Authors: Jaerisch Johannes , Sumi Hiroki
Published: November 2015

We investigate the dynamics of semigroups of rational maps on the Riemann sphere. To establish a fractal theory of the Julia sets of infinitely generated semigroups of rational maps, we introduce a new class of semigroups which we call nicely expanding rational semigroups. More precisely, we prove Bowen’s formula for the Hausdorff dimension of the pre-Julia sets, which we also introduce in this paper. We apply our results to the study of the Julia sets of non-hyperbolic rational semigroups. For these results, we do not assume the cone condition, which has been assumed in the study of infinite contracting iterated function systems. Similarly, we show that Bowen’s formula holds for the limit set of a contracting conformal iterated function system without the cone condition.
Characterisation theorem for best polynomial spline approximation with free knots
Authors: Sukhorukova Nadezda , Ugon Julien
Published: November 2015

In this paper, we derive a necessary condition for a best approximation by piecewise polynomial functions. We apply nonsmooth nonconvex analysis to obtain this result, which is also a necessary and sufficient condition for inf-stationarity in the sense of Demyanov-Rubinov. We start from identifying a special property of the knots. Then, using this property, we construct a characterisation theorem for best free-knots polynomial spline approximation, which is stronger than the existing characterisation results, at least in the case when only continuity is required.
Information Cost and Consumer Choices of Healthy Foods
Authors: Zhu Chen , Lopez Rigoberto A. , Liu Xiaoou
Published: November 2015

This article examines whether or not a reduction in consumer search cost for nutritional information increases the probability that heterogeneous consumers will choose healthier food products. Empirical results from the ready‐to‐eat breakfast cereal (RTEC) market confirm the conceptual analysis that lowering information cost via simplified nutritional labeling increases the healthfulness of consumer choices. The healthfulness attribute weighs 28.44% more heavily in consumers' decision‐making with simpler labeling systems. On average, introducing front‐of‐package labeling increased the probability of a consumer choosing a healthy RTEC by 3.49% and reduced the probability of choosing an unhealthy RTEC by 3.81%. Calories, sugar, saturated fat, and sodium consumption decrease by 0.31%, 2.63%, 6.94%, and 1.97%, respectively. Fiber intake increases by 3.24%. Further results show that less‐educated and smaller households with less frequent purchases benefit the most from a reduction in information cost. Overall, this article shows the potentially positive role that voluntary, more convenient labeling could play in improving market and public health outcomes.
On the Brukner–Zeilinger approach to information in quantum measurements
Authors: Rastegin A. E.
Published: November 2015

We address the problem of properly quantifying information in quantum theory. Brukner and Zeilinger proposed the concept of an operationally invariant measure based on measurement statistics. Their measure of information is calculated with probabilities generated in a complete set of mutually complementary observations. This approach was later criticized for several reasons. We show that some critical points can be overcome by means of natural extension or reformulation of the Brukner–Zeilinger approach. In particular, this approach is connected with symmetric informationally complete measurements. The ‘total information’ of Brukner and Zeilinger can further be treated in the context of mutually unbiased measurements as well as general symmetric informationally complete measurements. The Brukner–Zeilinger measure of information is also examined in the case of detection inefficiencies. It is shown to be decreasing under the action of bistochastic maps. The Brukner–Zeilinger total information can be used for estimating the map norm of quantum operations.
Genome-wide association and prediction reveals the genetic architecture of cassava mosaic disease resistance and prospects for rapid genetic improvement
Authors: Wolfe Marnin D. , Rabbi Ismail Y. , Egesi Chiedozie , Hamblin Martha , Kawuki Robert , Kulakow Peter , Lozano Roberto , Del Carpio Dunia Pino , Ramu Punna , Jannink Jean-Luc
Published: November 2015

Cassava (Manihot esculenta) is a crucial, under-researched crop feeding millions worldwide, especially in Africa. Cassava mosaic disease (CMD) has plagued production in Africa for over a century. Bi-parental mapping studies suggest primarily a single major gene mediates resistance. To be certain and to potentially identify new loci we conducted the first genome-wide association mapping study in cassava with 6128 African breeding lines. We also assessed the accuracy of genomic selection to improve CMD resistance. We found a single region on chromosome 8 accounts for most resistance but also identified 13 small effect regions. We found evidence that two epistatic loci and/or alternatively multiple resistance alleles exist at major QTL. We identified two peroxidases and one thioredoxin as candidate genes. Genomic prediction of additive and total genetic merit was accurate for CMD and will be effective both for selecting parents and identifying highly resistant clones as varieties.
The chromatin environment shapes DNA replication origin organization and defines origin classes
Authors: Cayrou Christelle , Ballester Benoit , Peiffer Isabelle , Fenouil Romain , Coulombe Philippe , Andrau Jean-Christophe , van Helden Jacques , Méchali Marcel
Published: November 2015

To unveil the still-elusive nature of metazoan replication origins, we identified them genome-wide and at unprecedented high-resolution in mouse ES cells. This allowed initiation sites (IS) and initiation zones (IZ) to be differentiated. We then characterized their genetic signatures and organization and integrated these data with 43 chromatin marks and factors. Our results reveal that replication origins can be grouped into three main classes with distinct organization, chromatin environment, and sequence motifs. Class 1 contains relatively isolated, low-efficiency origins that are poor in epigenetic marks and are enriched in an asymmetric AC repeat at the initiation site. Late origins are mainly found in this class. Class 2 origins are particularly rich in enhancer elements. Class 3 origins are the most efficient and are associated with open chromatin and polycomb protein-enriched regions. The presence of Origin G-rich Repeated elements (OGRE) potentially forming G-quadruplexes (G4) was confirmed at most origins. These coincide with nucleosome-depleted regions located upstream of the initiation sites, which are associated with a labile nucleosome containing H3K64ac. These data demonstrate that specific chromatin landscapes and combinations of specific signatures regulate origin localization. They explain the frequently observed links between DNA replication and transcription. They also emphasize the plasticity of metazoan replication origins and suggest that in multicellular eukaryotes, the combination of distinct genetic features and chromatin configurations act in synergy to define and adapt the origin profile.
E-money regulation for consumer protection
Authors: Dehghan Fariba , Haghighi Amirhossein
Published: November 2015

Purpose

– The purpose of this paper is to analyze the regulatory framework of e-money transactions in terms of consumer protection approach, the base for regulatory and supervisory system.

Design/methodology/approach

– This research is based on descriptive-qualitative studies in electronic and cyber commerce. The authors have first explained the importance of regulation for consumer protection and have then showed the position of regulation in e-money; thus, the authors have noted two important and predominant concepts of consumer protection: safe arrangement in e-money and problem of information secrecy and asymmetry. The leading approach in this paper is for efficient allocation of resources between dealers and player of this scope and the authors find consumer protection as the best regulation instrument in this way.

Findings

– The paper argues that e-money is an efficient and user-friendly payment system and might be used as a general means of payment in the real and virtual worlds. This finding provides a major reason for regulatory frameworks in e-money.

Originality/value

– Some important regulation applications in this new scope of commerce involve indirect interference and making orders in transactions. In this paper, the authors have focused on consumer protection regulation that may have a positive effect on dealers, businessmen and women in the long run; thus, this approach also compares other studies within the scope of e-money.
What factors influence firm perceptions of labour market constraints to growth in the MENA region?
Authors: Fakih Ali , Ghazalian Pascal L.
Published: November 2015

Purpose

– Labour market constraints constitute prominent obstacles to firm development and economic growth of countries located in the Middle East and North Africa (MENA) region. The purpose of this paper is to examine the implications of firm characteristics, national locations, and sectoral associations for the perceptions of firms concerning two basic labour market constraints: labour regulations and labour skill shortages.

Design/methodology/approach

– The empirical analysis is carried out using firm-level data set sourced from the World Bank’s Enterprise Surveys database. A bivariate probit estimator is used to account for potential correlations between the errors in the two labour market constraints’ equations. The authors implement overall estimations and comparative cross-country and cross-sector analyses, and use alternative estimation models.

Findings

– The empirical results reveal some important implications of firm characteristics (e.g. firm size, labour compositions) for firm perceptions of labour regulations and labour skill shortages. They also delineate important cross-country and cross-sector variations. The authors also find significant heterogeneity in the factors’ implications for the perceptions of firms belonging to different sectors and located in different MENA countries.

Originality/value

– Reforms in labour regulations and investment in human capital are important governmental policy interventions for promoting firm development and economic growth in the MENA region. This paper contributes to the empirical literature by analysing the factors influencing the perceptions of firms located in the MENA region concerning labour regulations and labour skill shortages. It provides policy-makers with information needed in the design of labour policies that attenuate the impacts of labour market constraints and enhance the performance of firms and the long-run economic growth.
Empirical investigation of balanced scorecard’s theoretical underpinnings
Authors: Sigalas Christos
Published: November 2015

Purpose

– The purpose of this study is to investigate empirically the balanced scorecard (BSC)’s theoretical underpinnings.

Design/methodology/approach

– This study undertakes a cross-sectional, self-administered e-mail survey to examine the convergent and discriminant validity of the performance indicators of the BSC’s four perspectives using principal components analysis and confirmatory factor analysis.

Findings

– The results suggest that the performance indicators of each BSC’s perspective converge with the same perspective’s performance indicators and discriminate from other perspectives’ performance indicators.

Research limitations/implications

– Future researchers are invited to conduct conceptual-level tests of the BSC framework using the newly constructed subjective scales of the performance indicators of the BSC’s perspectives. Furthermore, scholars conducting empirical research on the field are encouraged to further investigate the BSC’s theoretical underpinnings using various research designs, multiple research methods and a combination of existing and new BSC’s performance indicators.

Originality/value

– This study contributes to the academic stream of management accounting and strategic management field by: empirically validating the BSC’s theoretical underpinnings that is a prerequisite for the BSC to advance from a framework to a theory and providing subjective scales for measuring the generic performance indicators of the BSC’s four perspectives that can be used in future research of the BSC framework’s hypotheses. In addition, the literature is enhanced with a newly developed perceptual measure of firm performance with attributes of the BSC’s four perspectives.
Management accounting change: critical review and a new contextual framework
Authors: Alsharari Nizar Mohammad , Dixon Robert , Youssef Mayada Abd El-Aziz
Published: November 2015

Purpose

– This paper aims to introduce and discuss a new contextual framework to explain the processes of management accounting change in various organizations.

Design/methodology/approach

– Having an institutional perspective, the paper develops a “conceptual contextual framework” of management accounting change. The methodology to accomplish this theory building consists of an integration of a number of different works summarizing the common elements, contrasting the differences and extending the work in some fashion. Particularly, it draws on theoretical triangulation by adopting three approaches: old institutional economics for internal processes and factors (Burns and Scapens, 2000); new institutional sociology for external processes and pressures (Dillardet al., 2004); and power and politics mobilization (Hardy, 1996).

Findings

– The proposed framework provides an understanding of the complex “mixture” of interrelated factors that may influence management accounting change at multi-institutional levels: political and economic level, organizational field level and organizational level.

Research limitations/implications

– The framework extends institutional theory-based management accounting research as well as provides a comprehensive basis for examining dynamics of accounting in the institutionalization process. Through further research, the framework will be extended and refined.

Practical implications

– The paper has practical implications for practitioners and officers as well as for the accounting profession and academics alike.

Originality/value

– The proposed contextual framework provides insights into the processes of change by focusing attention on the underlying institutions that encode accounting systems or practices in three institutional levels: political and economic level, the organizational field level and organization level. Examining the tension between institutionalized beliefs and values that may occur between these three levels of institutions will enhance our understanding of management accounting change in organizations.
Changes in ownership forms and role of institutional investors in governing public companies in Malaysia
Authors: Annuar Hairul Azlan
Published: November 2015

Purpose

– The purpose of this paper is to ascertain whether different types of institutional investor in Malaysia are involved in the corporate governance of their investee companies, and, if yes, to what extent is the level of the involvement.

Design/methodology/approach

– A qualitative approach, consisting of a series of interviews with 18 senior investment managers of different types of institutional investor, was chosen.

Findings

– The findings suggest that lessons learnt from the fallout of the Asian crisis has made Malaysian institutional investors not only to be more prudent in managing their total funds and in making equities investment decisions, but has resulted in a more active participation in their “core” investee companies apart from merely discharging their voting rights. Interview analysis revealed that government-linked investment companies are championing the cause and could possibly affect the overall level of institutional investors’ involvement, which bode well for the future of the corporate governance system of the country.

Research limitations/implications

– Generalisations may be an issue when interviews are used as the method of inquiry. Also, the sample is not random, as access to many managers depended on recommendations. In addition, respondents were consciously selected to obtain different types of institutional investors that included government and non-government linked.

Originality/value

– There is a lack of work on studying the involvement of institutional investors in developing countries, whereby previous work and literature review were predominantly based upon the experience of Western economies.