bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of serial and concurrent training on acquisition and generalization
Authors: Wunderlich Kara L. , Vollmer Timothy R. , Donaldson Jeanne M. , Phillips Cara L.
Published: August 2014

Despite a large body of research demonstrating that generalization to novel stimuli can be produced by training sufficient exemplars, the methods by which exemplars can be trained remain unclear. The purpose of the current study was to evaluate 2 methods, serial and concurrent presentation of stimuli, to train sufficient exemplars. Five preschool children with developmental delays were taught to identify letters or letter sounds using serial and concurrent presentation. Generalization to untrained exemplars was evaluated for targets trained using each method. Participants reached the mastery criterion in fewer training sessions, on average, using the concurrent method of presentation than the serial method, and the concurrent method also resulted in greater generalization to untrained exemplars.

Video Methods
Influence of combined grazing by wild boar and small ruminant on soil and plant nutrient contents in a coppice oak forest
Authors: Parissi Zoi M. , Papaioannou Athanassios , Abraham Eleni M. , Kyriazopoulos Apostolos P. , Sklavou Paraskevi , Tsiouvaras Constantinos N.
Published: August 2014

Limited information is available about the impact of grazing on soil and plant nutrient contents in Mediterranean deciduous oak forests grazed by both livestock and wild life. Thus, the main objective of this study was to investigate the effect of wild boar and small ruminants grazing in a coppice oak forest in N Greece. Eight even‐aged stands of similar canopy cover and site quality were selected: four stands with long‐time grazing mainly by wild boar and four stands with long‐time grazing by sheep and goats. A plot of 150 m2in each of the stands was fenced in order to be protected from grazing. A similarly sized plot open to grazing was assigned next to the fenced plot. Species composition was recorded in fenced and grazed plots. Soil samples and individual plants of the dominant palatable grass speciesDactylis glomerata andBrachypodium sylvaticumwere collected in every fenced and grazed plot. These samples were analysed for contents of nutrients. The results indicated that grazing increased organic matter, C, and total N, P and Ca, while it had no effect on the plant nutrients Mg, Na, K and all micronutrients, and pH as well. Wild boar grazing had a significantly negative impact on the concentrations of Na, Fe, Zn, and Mn in the soil. Beside a decrease in K and Mn, grazing had minimal effects on the contents of plant nutrients. Conversely, wild boar grazing increased the contents of several nutrients such as N, Na, Cu and Fe in plant tissue. It seems that species composition was more affected by the topography and management than by the soil features as revealed by RDA analysis. The results of this study indicate that it is important to maintain moderate small ruminant grazing intensity for the sustainable multi‐disciplinary management of coppice oak forests. It is also important to control wild boar population in order to facilitate ecosystem process, soil preservation and forage quality.
Perceptions of Investors and Stockbrokers on Corporate Social Responsibility: A Stakeholder Perspective from India
Authors: Kansal Monika , Joshi Mahesh
Published: August 2014

This paper aims to understand the perceptions of shareholders and brokers regarding corporate social responsibility (CSR) initiatives by Indian companies. The research, presented in this paper, employs stakeholder theory to examine the perceptions of investors and sharebrokers on CSR in the context of a fast growing country, India. The data has been collected by using semistructured survey instrument. The findings of the study highlight that the respondents in both categories of stakeholder groups agree that CSR‐oriented companies enjoy higher levels of investor confidence, which is reflected in higher stock prices, and leads to enhanced reputation and corporate goodwill. The research demonstrates that Indian companies are in fact implementing CSR initiatives and that stakeholders have a considerable interest in such initiatives. Both the groups expect higher CSR disclosures from large corporations and multinational companies operating in India.

Educational initiatives have received maximum attention from the both the groups of stakeholders followed by the environmental issues. Investors are least aware of healthcare and rural development initiatives possibly because of the relatively low penetration of Indian financial markets into the rural areas. This study demonstrates that the stakeholder theory is a useful tool for collecting and evaluating CSR data and explains that the stakeholder perception of CSR performance determines corporate initiatives to a certain level. The findings would help in building consensus on strengthening the implementation and establishing the future CSR framework in emerging economies and other parts of the world. Copyright © 2014 John Wiley & Sons, Ltd.
A Systemic View of Corporate Social Responsibility (CSR) in State‐Owned Enterprises (SOEs)
Authors: Córdoba‐Pachón José‐Rodrigo , Garde‐Sánchez Raquel , Rodríguez‐Bolívar Manuel‐Pedro
Published: August 2014

Corporate social responsibility (CSR) continues to be an important topic in organisations worldwide. This paper considers the implementation of CSR by state‐owned enterprises (SOEs). In this type of organisation, the state acts as a powerful stakeholder as it acts as representative, guarantor and shareholder of public interests. SOEs would seem to be an ideal testing ground for assumptions about CSR that have been imported from the (US) private sector, in particular, how stakeholders can influence and be influenced by CSR policies. Against this background and drawing on diverse literature, this paper presents the features and challenges identified in the SOE sector in relation to CSR. It proposes a systemic view of CSR to identify relevant possibilities to help the advancement of CSR in this sector and from a perspective that considers the wider context of SOEs. Findings suggest that although senior SOE managers show awareness of and commitment to CSR principles through a number of fixed or static elements, there remains an imperative need to enhance their application of CSR in SOE plans, strategies and daily activities, in other words to adopt a more proactive, stakeholder awareness and dynamic view of CSR. Copyright © 2014 John Wiley & Sons, Ltd.
Data‐driven model reduction for the Bayesian solution of inverse problems
Authors: Cui Tiangang , Marzouk Youssef M. , Willcox Karen E.
Published: August 2014

One of the major challenges in the Bayesian solution of inverse problems governed by partial differential equations (PDEs) is the computational cost of repeatedly evaluating numerical PDE models, as required by Markov chain Monte Carlo (MCMC) methods for posterior sampling. This paper proposes a data‐driven projection‐based model reduction technique to reduce this computational cost. The proposed technique has two distinctive features. First, the model reduction strategy is tailored to inverse problems: the snapshots used to construct the reduced‐order model are computed adaptively from the posterior distribution. Posterior exploration and model reduction are thus pursued simultaneously. Second, to avoid repeated evaluations of the full‐scale numerical model as in a standard MCMC method, we couple the full‐scale model and the reduced‐order model together in the MCMC algorithm. This maintains accurate inference while reducing its overall computational cost. In numerical experiments considering steady‐state flow in a porous medium, the data‐driven reduced‐order model achieves better accuracy than a reduced‐order model constructed using the classical approach. It also improves posterior sampling efficiency by several orders of magnitude compared with a standard MCMC method. Copyright © 2014 John Wiley & Sons, Ltd.
Repetitive Sequences in Plant Nuclear DNA: Types, Distribution, Evolution and Function
Authors: Mehrotra Shweta , Goyal Vinod
Published: August 2014

Repetitive DNA sequences are a major component of eukaryotic genomes and may account for up to 90% of the genome size. They can be divided into minisatellite, microsatellite and satellite sequences. Satellite DNA sequences are considered to be a fast-evolving component of eukaryotic genomes, comprising tandemly-arrayed, highly-repetitive and highly-conserved monomer sequences. The monomer unit of satellite DNA is 150–400 base pairs (bp) in length. Repetitive sequences may be species- or genus-specific, and may be centromeric or subtelomeric in nature. They exhibit cohesive and concerted evolution caused by molecular drive, leading to high sequence homogeneity. Repetitive sequences accumulate variations in sequence and copy number during evolution, hence they are important tools for taxonomic and phylogenetic studies, and are known as “tuning knobs” in the evolution. Therefore, knowledge of repetitive sequences assists our understanding of the organization, evolution and behavior of eukaryotic genomes. Repetitive sequences have cytoplasmic, cellular and developmental effects and play a role in chromosomal recombination. In the post-genomics era, with the introduction of next-generation sequencing technology, it is possible to evaluate complex genomes for analyzing repetitive sequences and deciphering the yet unknown functional potential of repetitive sequences.
No longer an untreatable disease: How targeted and immunotherapies have changed the management of melanoma patients
Authors: Girotti Maria Romina , Saturno Grazia , Lorigan Paul , Marais Richard
Published: August 2014

The discovery that BRAF is a driver oncogene in cancer, and complementary improvements in our understanding of the immune system have resulted in new targeted and immune‐therapies for metastatic melanoma. Targeted therapies achieve impressive clinical results in carefully selected patients but the development of resistance seems inevitable in most cases. Conversely, immune‐checkpoints inhibitors can achieve long‐term remission and cures, but in a smaller proportion of patients, and biomarkers to predict which patients will respond are not available. Nevertheless, melanoma has led the evolution of cancer treatment from relatively nonspecific cytotoxic agents to highly selective therapies and here we review the lessons from this paradigm shift in treatment and the opportunities for further improvements in outcomes for melanoma patients.
Heinrich event 4 and Dansgaard/Oeschger events 5–10 recorded by high-resolution speleothem oxygen isotope data from central China
Authors: Zhou Houyun , Zhao Jian-xin , Feng Yuexing , Chen Qiong , Mi Xiaojian , Shen Chuan-Chou , He Haibo , Yang Liang , Liu Shuhua , Chen Lin , Huang Jiayi , Zhu Liyan
Published: August 2014

A 50-yr resolution reconstruction of climate and environment variability during the period 43–14 ka was developed using 26 high-precision U/Th dates and 390 oxygen isotope (δ18O) data of a stalagmite (SJ1) collected from Songjia Cave in central China, which is close to the northwestern boundary of the Asian summer monsoon (ASM). The δ18O record in SJ1 displays significant millennial-scale changes that correlate well in timing and duration with Dansgaard/Oeschger (D/O) events 5–10 and Heinrich event 4 (H4) identified in high-latitude regions of the Northern Hemisphere. Four 230Th dates constrain the H4 event precisely to the period of 39.7 to 38.3 ka. Notable centennial variations of the ASM activity could be observed within the H4 event. The magnitude and duration of D/O event 4.1 recorded in SJ1 are similar to those archived in east China but different from those documented in southwest China, suggesting that the manifestation of this event may be regionally different. The timing, duration and structure of D/O events 5–10 and Heinrich event 4 suggest that temperature changes in both hemispheres have exerted significant influences on the ASM variations in central China.
Hedonic tone is associated with left supero-lateral medial forebrain bundle microstructure
Authors: Bracht T. , Doidge A. N. , Keedwell P. A. , Jones D. K.
Published: August 2014

Background.

The medial forebrain bundle (MFB) is an important pathway of the reward system. Two branches have been described using diffusion magnetic resonance imaging (MRI)-based tractography: the infero-medial MFB (imMFB) and the supero-lateral MFB (slMFB). Previous studies point to white-matter microstructural alterations of the slMFB in major depressive disorder (MDD) during acute episodes. To extend this finding, this study investigates whether white-matter microstructure is also altered in MDD patients that are in remission. Further, we explore associations between diffusion MRI-based metrics of white-matter microstructure of imMFB, slMFB and hedonic tone, the ability to derive pleasure.

Method.

Eighteen remitted depressed (RD) and 22 never depressed (ND) participants underwent high angular resolution diffusion-weighted imaging (HARDI) scans. To reconstruct the two pathways of the MFB (imMFB and slMFB) we used the damped Richardson–Lucy (dRL) algorithm. Mean fractional anisotropy (FA) was sampled along the tracts.

Results.

Mean FA of imMFB, slMFB and a comparison tract (the middle cerebellar peduncle) did not differ between ND and RD participants. Hedonic capacity correlated negatively with mean FA of the left slMFB, explaining 21% of the variance.

Conclusions.

Diffusion MRI-based metrics of white-matter microstructure of the MFB in RD do not differ from ND. Hedonic capacity is associated with altered white-matter microstructure of the slMFB.
From Housewives to Independent Earners: How the Tax System Can Help Women to Work in a Context of Strong Familialism
Authors: FIGARI FRANCESCO
Published: August 2014

The Southern European countries share a similar welfare system which does not perform well either in terms of equity or efficiency. Using EUROMOD, the EU-wide microsimulation model, this paper evaluates the enhancement of both the redistributive and the incentive effects of the Italian tax-benefit system by introducing either a family-based or an individual in-work benefit, financed through the abolition of the existing tax credit targeted at dependent adults. The results show an increase in the labour supply of women both in couples and lone mothers, in particular among the poorest, with important redistributive effects. The in-work benefits can contribute to the de-familialisation of the Mediterranean welfare states by reducing the reliance on the family and compensating the cost of services.
The sources of granitic melt in Deep Hot Zones
Authors: Annen Catherine , Blundy Jonathan D. , Sparks R. Stephen J.
Published: August 2014

A Deep Hot Zone develops when numerous mafic sills are repeatedly injected at Moho depth or are scattered in the lower crust. The melt generation is numerically modelled for mafic sill emplacement geometries by overaccretion, underaccretion or random emplacement, and for intrusion rates of 2, 5 and 10mm/yr. After an incubation period, melts are generated by incomplete crystallisation of the mafic magma and by partial melting of the crust. The first melts generated are residual from the mafic magmas that have low solidi due to concentration of H20 in the residual liquids. Once the solidus of the crust is reached, the ratio of crustal partial melt to residual melt increases to a maximum. If wet mafic magma, typical of arc environments, is injected in an amphibolitic crust, the residual melt is dominant over the partial melt, which implies that the generation of I-type granites is dominated by the crystallisation of mafic magma originated from the mantle and not by the partial melting of earlier underplated material. High ratios of crustal partial melt over residual melt are reached when sills are scattered in a metasedimentary crust, allowing the generation of S-type granites. The partial melting of a refractory granulitic crust intruded by dry, high-T mafic magma is limited and subordinate to the production of larger amount of residual melt in the mafic sills. Thus the generation of A-type granites by partial melting of a refractory crust would require a mechanism of selective extraction of the A-type melt.
The chemical character of the Late Caledonian Donegal Granites, Ireland, with comments on their genesis
Authors: Ghani Azman A. , Atherton Michael P.
Published: August 2014

The Late Caledonian granites of Donegal are all intruded into metasediments of the Dalradian Supergroup of Neoproterozoic age, which were metamorphosed and deformed during the Grampian Phase of the Caledonian orogeny at c. 470–460 m.y. They were intruded in a singular pulse well after the main tectonic event, apparently peaking at 407–402 m.y.; importantly after the strong collision of Laurentia with Baltica on closure of the Iapetus Ocean. The plutons are mainly made up of granodiorite and granite, and are all 'I' type, but different to Cordilleran ‘I’ types of the eastern Pacific margin. Major element chemistry indicates they are high-K calc-alkaline rocks with a large range in SiO2 content. However three of the plutons (Fanad, Thorr, Ardara), have very high Ba and Sr contents, even higher than Mainland Scotland counterparts; they are high Ba–Sr plutons. Three plutons (Barnesmore, Rosses, Trawenagh Bay) are evolved and are low-Ba–Sr types, while one (Main Donegal) has atypical, intermediate characteristics. The origin of the magmas is still much debated; here we suggest slab breakoffon Iapetus Ocean closure accounts for the special compositions of these magmas and the other major features of Late Caledonian granitic magmatism, including the singular intrusion peak and the associated appinite–lamprophyre suite.
Delirium screening anchored in child development: The Cornell Assessment for Pediatric Delirium
Authors: Silver Gabrielle , Kearney Julia , Traube Chani , Hertzig Margaret
Published: August 2014

Objective:

The recently validated Cornell Assessment for Pediatric Delirium (CAPD) is a new rapid bedside nursing screen for delirium in hospitalized children of all ages. The present manuscript provides a “developmental anchor points” reference chart, which helps ground clinicians' assessment of CAPD symptom domains in a developmental understanding of the presentation of delirium.

Method:

During the development of this CAPD screening tool, it became clear that clinicians need specific guidance and training to help them draw on their expertise in child development and pediatrics to improve the interpretative reliability of the tool and its accuracy in diagnosing delirium. The developmental anchor points chart was formulated and reviewed by a multidisciplinary panel of experts to evaluate content validity and include consideration of sick behaviors within a hospital setting.

Results:

The CAPD developmental anchor points for the key ages of newborn, 4 weeks, 6 weeks, 8 weeks, 28 weeks, 1 year, and 2 years served as the basis for training bedside nurses in scoring the CAPD for the validation trial and as a multifaceted bedside reference chart to be implemented within a clinical setting. In the current paper, we discuss the lessons learned during implementation, with particular emphasis on the importance of collaboration with the bedside nurse, the challenges of establishing a developmental baseline, and further questions about delirium diagnosis in children.

Significance of Results:

The CAPD with developmental anchor points provides a validated, structured, and developmentally informed approach to screening and assessment of delirium in children. With minimal training on the use of the tool, bedside nurses and other pediatric practitioners can reliably identify children at risk for delirium.
Search for Vigna species conferring resistance to Mungbean yellow mosaic virus in mungbean
Authors: Sudha M. , Karthikeyan A. , Shobhana V. G. , Nagarajan P. , Raveendran M. , Senthil N. , Pandiyan M. , Angappan K. , Balasubramanian P. , Rabindran R. , Bharathi M.
Published: August 2014

Mungbean yellow mosaic virus (MYMV) is a disastrous pathogen of mungbean. It is widespread in most of southern India and no complete resistance has been identified among its commercial cultivars. Two isolates of MYMV, representing its diversity, were used to assess and characterize the susceptibility reaction of all the three species of Vigna. The seeds were agroinoculated with the virus and the presence of the viral DNA was confirmed after 12 d by reverse transcriptase-polymerase chain reaction (RT-PCR) analysis after which the plants were monitored for the expression of symptoms. All of the 20 accessions of Vigna radiata and ten accessions of Vigna mungo were systemically infected with MYMV, and they all produced typical symptoms. On the other hand, the 24 accessions of Vigna umbellata were found to be resistant to both the isolates. For additional affirmation, three representative accessions of V. radiata and V. mungo and all the accessions of V. umbellata were agroinoculated, and quantitative RT-PCR was performed for the quantitative detection of the MYMV. The mRNA transcripts of MYMV were detected in V. radiata and V. mungo plants but not in the V. umbellata plants. Researching the molecular basis of the resistance in V. umbellate against MYMV might definitely be very constructive for developing resistant varieties of mungbean on a commercial scale. This genetic quality offering resistance to MYMV could also be incorporated into V. radiata/V. mungo by means of interspecific crosses.
A 3-D diamondoid MOF catalyst based on in situ generated [Cu(L)2] N-heterocyclic carbene (NHC) linkers: hydroboration of CO2
Authors: Burgun Alexandre , Crees Rachel S. , Cole Marcus L. , Doonan Christian J. , Sumby Christopher J.
Published: August 2014

A new MOF, [Zn4O{Cu(L)2}2], with 14 Å channels lined by in situ generated [Cu(L)2] N-heterocyclic carbene linkers catalyses the hydroboration of CO2.
Tri- and tetradentate copper complexes: a comparative study on homogeneous and heterogeneous catalysis over oxidation reactions
Authors: Titinchi Salam J. J. , Von Willingh Gavin , Abbo Hanna S. , Prasad Rajendra
Published: August 2014

A comparative catalytic study between heterogeneous (zeolite-encapsulated Cu complexes) and homogeneous analogues over oxidation reactions was undertaken in detail.
New Zn2+ coordination polymers constructed from acylhydrazidate molecules: synthesis and structural characterization
Authors: Wang Yan-Ning , Li Guang-Hua , Bai Fu-Quan , Yu Jie-Hui , Xu Ji-Qing
Published: August 2014

Two types of hydrothermal in situ ligand reactions were employed to obtain three new acylhydrazidate-extended Zn2+ coordination polymers.
Low-temperature microwave-assisted pyrolysis of waste office paper and the application of bio-oil as an Al adhesive
Authors: Zhang Zhanrong , Macquarrie Duncan J. , De bruyn Mario , Budarin Vitaliy L. , Hunt Andrew J. , Gronnow Mark J. , Fan Jiajun , Shuttleworth Peter S. , Clark James H. , Matharu Avtar S.
Published: August 2014

The potential application of waste office paper derived bio-oil as an Al–Al adhesive is reported.
An integrated CMOS quantitative-polymerase-chain-reaction lab-on-chip for point-of-care diagnostics
Authors: Norian Haig , Field Ryan M. , Kymissis Ioannis , Shepard Kenneth L.
Published: August 2014

qPCR demonstrated on the surface of a CMOS integrated circuit using embedded heaters, temperature sensors, photodiodes, and electrowetting-based droplet transport mechanism.
Mechanisms for enzymatic cleavage of the N-glycosidic bond in DNA
Authors: Drohat Alexander C. , Maiti Atanu
Published: August 2014

We review advances in understanding the mechanism of DNA glycosylases, emphasizing the role of the nucleobase leaving-group.
Synthesis and characterization of a starch–AlOOH–FeS2 nanocomposite for the adsorption of congo red dye from aqueous solution
Authors: Kumar Rajeev , Rashid Jamshaid , Barakat M. A.
Published: August 2014

This work described the synthesis and characterization of a starch–AlOOH–FeS2 nanocomposite for the adsorption of congo red (CR) dye from aqueous solution.
Equilibrium and kinetics of aniline adsorption onto crosslinked sawdust-cyclodextrin polymers
Authors: Hu Qi , Gao Da-Wen , Pan Hongyu , Hao Linlin , Wang Peng
Published: August 2014

Equilibrium and kinetic studies of aniline adsorption onto crosslinked sawdust-cyclodextrin polymers.
Importance and synthesis of benzannulated medium-sized and macrocyclic rings (BMRs)
Authors: Hussain Altaf , Yousuf S. K. , Mukherjee Debaraj
Published: August 2014

Cyclic molecular frameworks, especially the benzannulated medium-sized and macrocyclic ring (BMR) systems, constitute an integral component of a large number of biologically significant natural or synthetic molecules.
Optical coherence tomography velocimetry of colloidal suspensions
Authors: Malm A. V. , Harrison A. W. , Waigh T. A.
Published: August 2014

Optical coherence tomography velocimetry combined with a rheometer and optical modulation techniques provides increased sensitivity to the low shear rate motion of complex fluid systems.
3-D scaffold platform for optimized non-viral transfection of multipotent stem cells
Authors: Yu Xiaohua , Murphy William L.
Published: August 2014

An enhanced throughput, 3D scaffold platform can be used to screen for the influence of mineral coating properties on stem cell transfection.
A new tumour suppression mechanism by p27Kip1: EGFR down-regulation mediated by JNK/c-Jun pathway inhibition
Authors: Fang Yong , Wang Yihong , Wang Yulei , Meng Yan , Zhu Junlan , Jin Honglei , Li Jingxia , Zhang Dongyun , Yu Yonghui , Wu Xue-Ru , Huang Chuanshu
Published: August 2014

p27Kip1 is a potent inhibitor of cyclin-dependent kinases that drive G1-to-S cell-cycle transition. Reduced p27Kip1 expression is prevalent in a wide range of human tumours; however, the exact mechanism(s) of p27Kip1-mediated tumour suppression remains obscure. In the present study, we identified a close inverse relationship between p27Kip1 and EGFR (epidermal growth factor receptor) expression: the parental T24 human bladder cancer cells had high p27Kip1 expression but low EGFR expression and, in striking contrast, the metastatic derivative of T24 (T24T) had low p27Kip1 expression but high EGFR expression. This relationship was also found in various human cancer tissues, and was not only just correlative but also causal; depletion of p27Kip1 in MEF (mouse embryonic fibroblast) cells resulted in markedly elevated EGFR expression, a result reproducible with an Egfr promoter-luciferase reporter in both T24 and MEF cells, suggesting transcriptional repression of EGFR by p27Kip1. Indeed, p27Kip1 was found to regulate EGFR expression via the JNK (c-Jun N-terminal kinase)/c-Jun transcription factor: p27Kip1 deficiency activated JNK/c-Jun, whereas inhibition of JNK/c-Jun by dominant-negative mutants dramatically repressed Egfr transcription. Furthermore, the proximal promoter of the Egfr gene was crucial for its transcription, where the recruiting activity of c-Jun was much greater in p27Kip1−/− cells than in p27Kip1+/+ cells. Introduction of GFP–p27Kip1 into T24T cells suppressed JNK/c-Jun activation, EGFR expression and anchorage-independent growth. The results of the present study demonstrate that p27Kip1 suppresses JNK/c-Jun activation and EGFR expression in MEFs and human bladder cancer cells, and the results obtained are consistent with those from human cancer specimens. The present study provides new insights into p27Kip1 suppression of cancer cell growth, migration and metastasis.
Novel Switching pattern for single‐stage current source inverter for grid‐connected photovoltaics
Authors: Ebrahimi Anooshirvan , Fathi Hamid S. , Gholamrezaei Hossein
Published: August 2014

Environmental pollution and economic issues are major problems which result in an ascending increase of renewable sources such as photovoltaic and fuel cells. The low DC‐voltage generated by these sources needs to be boosted to the level of the grid before being inverted. A single stage three‐phase boost inverter is utilised to perform the action of increasing and inverting. A switching algorithm is applied to this topology to control the charging time and discharging interval of converters inductor. A simple control strategy is applied to this configuration which is responsible for regulating the transfer power to the maximum amount and also to justify the amount of THD in minimum point. Simulation results performed in MATLAB software show the effectiveness of using this switching strategy and control approach. Experimental results are presented to verify the simulation results.
Indirect-to-direct band gap transition in relaxed and strained Ge1−x−ySixSny ternary alloys
Authors: Attiaoui Anis , Moutanabbir Oussama
Published: August 2014

Sn-containing group IV semiconductors create the possibility to independently control strain and band gap thus providing a wealth of opportunities to develop an entirely new class of low dimensional systems, heterostructures, and silicon-compatible electronic and optoelectronic devices. With this perspective, this work presents a detailed investigation of the band structure of strained and relaxed Ge1−x−ySixSny ternary alloys using a semi-empirical second nearest neighbors tight binding method. This method is based on an accurate evaluation of the deformation potential constants of Ge, Si, and α-Sn using a stochastic Monte-Carlo approach as well as a gradient based optimization method. Moreover, a new and efficient differential evolution approach is also developed to accurately reproduce the experimental effective masses and band gaps. Based on this, we elucidated the influence of lattice disorder, strain, and composition on Ge1−x−ySixSny band gap energy and directness. For 0 ≤ x ≤ 0.4 and 0 ≤ y ≤ 0.2, we found that tensile strain lowers the critical content of Sn needed to achieve a direct band gap semiconductor with the corresponding band gap energies below 0.76 eV. This upper limit decreases to 0.43 eV for direct gap, fully relaxed ternary alloys. The obtained transition to direct band gap is given by y > 0.605 × x + 0.077 and y > 1.364 × x + 0.107 for epitaxially strained and fully relaxed alloys, respectively. The effects of strain, at a fixed composition, on band gap directness were also investigated and discussed.
Radial profile measurements of plasma pressure-like fluctuations with the heavy ion beam diagnostic on the tokamak ISTTOK
Authors: Henriques R. B. , Malaquias A. , Nedzelskiy I. S. , Silva C. , Coelho R. , Figueiredo H. , Fernandes H.
Published: August 2014

The Heavy Ion Beam Diagnostic (HIBD) on the tokamak ISTTOK (Instituto Superior Técnico TOKamak) has been modified, in terms of signal conditioning, to measure the local fluctuations of the neσ1,2(Te) product (plasma density times the effective ionization cross-section) along the tokamak minor diameter, in 12 sample volumes in the range of −0.7a < r < 0.7a, with a maximum delay time of 1 μs. The corresponding signals show high correlation with the magnetic Mirnov coils in the characteristic MHD frequency range of ISTTOK plasmas and enable the identification of tearing modes. This paper describes the HIBD signal conditioning system and presents a preliminary analysis of the radial profile measurements of local neσ1,2(Te) fluctuations.
Resolving small signal measurements in experimental plasma environments using calibrated subtraction of noise signals
Authors: Fimognari P. J. , Demers D. R. , Chen X. , Schoch P. M.
Published: August 2014

The performance of many diagnostic and control systems within fusion and other fields of research are often detrimentally affected by spurious noise signals. This is particularly true for those (such as radiation or particle detectors) working with very small signals. Common sources of radiated and conducted noise in experimental fusion environments include the plasma itself and instrumentation. The noise complicates data analysis, as illustrated by noise on signals measured with the heavy ion beam probe (HIBP) installed on the Madison Symmetric Torus. The noise is time-varying and often exceeds the secondary ion beam current (in contrast with previous applications). Analysis of the noise identifies the dominant source as photoelectric emission from the detectors induced by ultraviolet light from the plasma. This has led to the development of a calibrated subtraction technique, which largely removes the undesired temporal noise signals from data. The advantages of the technique for small signal measurement applications are demonstrated through improvements realized on HIBP fluctuation measurements.
Tensile testing of materials at high temperatures above 1700 °C with in situ synchrotron X-ray micro-tomography
Authors: Haboub Abdel , Bale Hrishikesh A. , Nasiatka James R. , Cox Brian N. , Marshall David B. , Ritchie Robert O. , MacDowell Alastair A.
Published: August 2014

A compact ultrahigh temperature tensile testing instrument has been designed and fabricated for in situ x-ray micro-tomography using synchrotron radiation at the Advanced Light Source, Lawrence Berkeley National Laboratory. It allows for real time x-ray micro-tomographic imaging of test materials under mechanical load at temperatures up to 2300 °C in controlled environments (vacuum or controlled gas flow). Sample heating is by six infrared halogen lamps with ellipsoidal reflectors arranged in a confocal configuration, which generates an approximately spherical zone of high heat flux approximately 5 mm in diameter. Samples are held between grips connected to a motorized stage that loads the samples in tension or compression with forces up to 2.2 kN. The heating chamber and loading system are water-cooled for thermal stability. The entire instrument is mounted on a rotation stage that allows stepwise recording of radiographs over an angular range of 180°. A thin circumferential (360°) aluminum window in the wall of the heating chamber allows the x-rays to pass through the chamber and the sample over the full angular range. The performance of the instrument has been demonstrated by characterizing the evolution of 3D damage mechanisms in ceramic composite materials under tensile loading at 1750 °C.
Design and initial operation of a two-color soft x-ray camera system on the Compact Toroidal Hybrid experiment
Authors: Herfindal J. L. , Dawson J. D. , Ennis D. A. , Hartwell G. J. , Loch S. D. , Maurer D. A.
Published: August 2014

A multi-camera soft x-ray diagnostic has been developed to measure the equilibrium electron temperature profile and temperature fluctuations due to magnetohydrodynamic activity on the Compact Toroidal Hybrid experiment. The diagnostic consists of three separate cameras each employing two 20-channel diode arrays that view the same plasma region through different beryllium filter thicknesses of 1.8 μm and 3.0 μm allowing electron temperature measurements between 50 eV and 200 eV. The Compact Toroidal Hybrid is a five-field period current-carrying stellarator, in which the presence of plasma current strongly modifies the rotational transform and degree of asymmetry of the equilibrium. Details of the soft x-ray emission, effects of plasma asymmetry, and impurity line radiation on the design and measurement of the two-color diagnostic are discussed. Preliminary estimates of the temperature perturbation due to sawtooth oscillations observed in these hybrid discharges are given.
Structure functions and applicability of Yaglom's relation in passive-scalar turbulent mixing at low Schmidt numbers with uniform mean gradient
Authors: Iyer K. P. , Yeung P. K.
Published: August 2014

An extensive direct numerical simulation database over a wide range of Reynolds and Schmidt numbers is used to examine the Schmidt number dependence of the structure function of passive scalars and the applicability of the so-called Yaglom's relation in isotropic turbulence with a uniform mean scalar gradient. For the moderate Reynolds numbers available, the limited range of scales in scalar fields of very low Schmidt numbers (as low as 1/2048) is seen to lead to weaker intermittency, and weaker alignment between velocity gradients and principal strain rates. Strong departures from both Obukhov-Corrsin scaling for second-order structure functions and Yaglom's relation for the mixed velocity-scalar third-order structure function are observed. Evaluation of different terms in the scalar structure function budget equation assuming statistical stationarity in time shows that, if the Schmidt number is very low, at intermediate scales production and diffusion terms (instead of advection) are major contributors in the balance against dissipation.
An improved classical mapping method for homogeneous electron gases at finite temperature
Authors: Liu Yu , Wu Jianzhong
Published: August 2014

We introduce a modified classical mapping method to predict the exchange-correlation free energy and the structure of homogeneous electron gases (HEG) at finite temperature. With the classical map temperature parameterized on the basis of the quantum Monte Carlo simulation data for the correlation energy and exact results at high and low temperature limits, the new theoretical procedure greatly improves the classical mapping method for correlating the energetic properties HEG over a broad range of thermodynamic conditions. Improvement can also be identified in predicting the long-range components of the spin-averaged pair correlation functions.
Pillar shape modulation in epitaxial BiFeO3–CoFe2O4 vertical nanocomposite films
Authors: Kim Dong Hun , Aimon Nicolas M. , Ross C. A.
Published: August 2014

Self-assembled epitaxial CoFe2O4-BiFeO3 nanocomposite films, in which pillars of CoFe2O4 grow within a single crystal BiFeO3 matrix, show both ferrimagnetism and ferroelectricity. The pillars typically have a uniform cross-section, but here two methods are demonstrated to produce a width modulation during growth by pulsed laser deposition. This was achieved by growing a blocking layer of BiFeO3 to produce layers of separated pillars or pillars with constrictions, or by changing the temperature during growth to produce bowling-pin shaped pillars. Modulated nanocomposites showed changes in their magnetic anisotropy compared to nanocomposites with uniform width. The magnetic anisotropy was interpreted as a result of magnetoelastic and shape anisotropies.
Strain and electric field induced electronic properties of two-dimensional hybrid bilayers of transition-metal dichalcogenides
Authors: Sharma Munish , Kumar Ashok , Ahluwalia P. K. , Pandey Ravindra
Published: August 2014

Tunability of the electronic properties of two-dimensional bilayer hetero structures of transition-metal dichalcogenides (i.e., MX2-M′X′2 with (M, M′ = Mo, W; X, X′ = S, Se) is investigated. Application of both strain and electric field is found to modify the band gap and carrier effective mass in the hybrid bilayers considered. The calculated results based on density functional theory suggest that the tensile strain considerably changes the band gap of semiconducting bilayers; it makes the band gap to be indirect, and later initiates the semiconductor-to-metal transition. Application of the external electric fields, on the other hand, shows asymmetric variation in the band gap leading to the closure of the gap at about 0.5–1.0 V/Å. Tuning of the band gap and carrier effective mass in such a controlled manner makes the hybrid bilayers of transition metal dichalcogenides to be promising candidates for application in electronic devices at nanoscale.
Communication: Escape kinetics of self-propelled Janus particles from a cavity: Numerical simulations
Authors: Ghosh Pulak Kumar
Published: August 2014

We numerically investigate the escape kinetics of elliptic Janus particles from narrow two-dimensional cavities with reflecting walls. The self-propulsion velocity of the Janus particle is directed along either their major (prolate) or minor (oblate) axis. We show that the mean exit time is very sensitive to the cavity geometry, particle shape, and self-propulsion strength. The mean exit time is found to be a minimum when the self-propulsion length is equal to the cavity size. We also find the optimum mean escape time as a function of the self-propulsion velocity, translational diffusion, and particle shape. Thus, effective transport control mechanisms for Janus particles in a channel can be implemented.
Mechanochromic polyurethane strain sensor
Authors: Cellini F. , Khapli S. , Peterson S. D. , Porfiri M.
Published: August 2014

In this Letter, we study the mechanical and optical response of a thermoplastic polyurethane blended with 0.5 wt. % of bis(benzoxazolyl)stilbene dye. The mechanochromic behavior of the material is characterized in a uniaxial stress-relaxation test by simultaneously acquiring the applied force, mechanical deformation, and fluorescence emission. To offer insight into the stress-strain response of the polymer-dye blend, we adapt a classical nonlinear constitutive behavior for elastomeric materials that accounts for stress-induced softening. We correlate the fluorescent response with the mechanical strain to demonstrate the possibility of accurate strain sensing for a broad range of deformations during both loading and unloading.
Effect of substrate temperature on the microstructural properties of titanium nitride nanowires grown by pulsed laser deposition
Authors: Gbordzoe S. , Kotoka R. , Craven Eric , Kumar D. , Wu F. , Narayan J.
Published: August 2014

The current work reports on the growth and microstructural characterization of titanium nitride (TiN) nanowires on single crystal silicon substrates using a pulsed laser deposition method. The physical and microstructural properties of the nanowires were characterized using field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). The corrosion properties of the TiN nanowires compared to TiN thin film were evaluated using Direct Current potentiodynamic and electrochemical impedance spectroscopy. The nanowires corroded faster than the TiN thin film, because the nanowires have a larger surface area which makes them more reactive in a corrosive environment. It was observed from the FESEM image analyses that as the substrate temperature increases from 600 °C to 800 °C, there was an increase in both diameter (25 nm–50 nm) and length (150 nm–250 nm) of the nanowire growth. There was also an increase in spatial density with an increase of substrate temperature. The TEM results showed that the TiN nanowires grow epitaxially with the silicon substrate via domain matching epitaxy paradigm, despite a large misfit.
From Schottky to Ohmic graphene contacts to AlGaN/GaN heterostructures: Role of the AlGaN layer microstructure
Authors: Fisichella G. , Greco G. , Roccaforte F. , Giannazzo F.
Published: August 2014

The electrical behaviour of graphene (Gr) contacts to AlxGa1−xN/GaN heterostructures has been investigated, focusing, in particular, on the impact of the AlGaN microstructure on the current transport at Gr/AlGaN interface. Two Al0.25Ga0.75N/GaN heterostructures with very different quality in terms of surface roughness and defectivity, as evaluated by atomic force microscopy (AFM) and transmission electron microscopy, were compared in this study, i.e., a uniform and defect-free sample and a sample with a high density of typical V-defects, which locally cause a reduction of the AlGaN thickness. Nanoscale resolution current voltage (I-V) measurements by an Au coated conductive AFM tip were carried out at several positions both on the bare and Gr-coated AlGaN surfaces. Rectifying contacts were found onto both bare AlGaN surfaces, but with a more inhomogeneous and lower Schottky barrier height (ΦB ≈ 0.6 eV) for AlGaN with V-defects, with respect to the case of the uniform AlGaN (ΦB ≈ 0.9 eV). Instead, very different electrical behaviours were observed in the presence of the Gr interlayer between the Au tip and AlGaN, i.e., a Schottky contact with reduced barrier height (ΦB ≈ 0.4 eV) for the uniform AlGaN and an Ohmic contact for the AlGaN with V-defects. Interestingly, excellent lateral uniformity of the local I-V characteristics was found in both cases and can be ascribed to an averaging effect of the Gr electrode over the AlGaN interfacial inhomogeneities. Due to the locally reduced AlGaN layer thickness, V defect act as preferential current paths from Gr to the 2DEG and can account for the peculiar Ohmic behaviour of Gr contacts on defective AlGaN.
Plaque and arterial vulnerability investigation in a three-layer atherosclerotic human coronary artery using computational fluid-structure interaction method
Authors: Karimi Alireza , Navidbakhsh Mahdi , Razaghi Reza
Published: August 2014

Coronary artery disease is the common form of cardiovascular diseases and known to be the main reason of deaths in the world. Fluid-Structure Interaction (FSI) simulations can be employed to assess the interactions of artery/plaque and blood to provide a more precise anticipation for rupture of arterial tissue layers and plaque tissues inside an atherosclerotic artery. To date, the arterial tissue in computational FSI simulations has been considered as a one-layer structure. However, a single layer assumption might have deeply bounded the results and, consequently, more computational simulation is needed by considering the arterial tissue as a three-layer structure. In this study, a three-dimensional computational FSI model of an atherosclerotic artery with a three-layer structure and different plaque types was established to perform a more accurate arterial wall/plaque tissue vulnerability assessment. The hyperelastic material coefficients of arterial layers were calculated and implemented in the computational model. The fully coupled fluid and structure models were solved using the explicit dynamics finite element code LS-DYNA. The results revealed the significant role of plaque types in the normal and shear stresses induced within the arterial tissue layers. The highest von Mises and shear stresses were observed on the stiffest calcified plaque with 3.59 and 3.27 MPa, while the lowest von Mises and shear stresses were seen on the hypocellular plaque with 1.15 and 0.63 MPa, respectively. Regardless of plaque types, the media and adventitia layers were played protective roles by displaying less stress on their wall, whilst the intima layer was at a high risk of rupture. The findings of this study have implications not only for determining the most vulnerable arterial layer/plaque tissue inside an atherosclerotic coronary artery but also for balloon-angioplasty, stenting, and bypass surgeries.
Autocorrelation measurement of femtosecond laser pulses based on two-photon absorption in GaP photodiode
Authors: Chong E. Z. , Watson T. F. , Festy F.
Published: August 2014

Semiconductor materials which exhibit two-photon absorption characteristic within a spectral region of interest can be useful in building an ultra-compact interferometric autocorrelator. In this paper, we report on the evidence of a nonlinear absorption process in GaP photodiodes which was exploited to measure the temporal profile of femtosecond Ti:sapphire laser pulses with a tunable peak wavelength above 680 nm. The two-photon mediated conductivity measurements were performed at an average laser power of less than a few tenths of milliwatts. Its suitability as a single detector in a broadband autocorrelator setup was assessed by investigating the nonlinear spectral sensitivity bandwidth of a GaP photodiode. The highly favourable nonlinear response was found to cover the entire tuning range of our Ti:sapphire laser and can potentially be extended to wavelengths below 680 nm. We also demonstrated the flexibility of GaP in determining the optimum compensation value of the group delay dispersion required to restore the positively chirped pulses inherent in our experimental optical system to the shortest pulse width possible. With the rise in the popularity of nonlinear microscopy, the broad two-photon response of GaP and the simplicity of this technique can provide an alternative way of measuring the excitation laser pulse duration at the focal point of any microscopy systems.