bluuebunny/crossref_metadata_2025 huggingface dataset:
Atomistic modeling of the directed-assembly of bimetallic Pt-Ru nanoclusters on Ru(0001)-supported monolayer graphene
Authors: Han Yong , Engstfeld Albert K. , Behm R. Juergen , Evans James W.
Published: April 2013

The formation of Pt-Ru nanoclusters (NCs) by sequential deposition of Pt and Ru on a periodically rumpled graphene sheet supported on Ru(0001) is analyzed by atomistic-level modeling and kinetic Monte Carlo simulations. The “coarse-scale” periodic variation of the adsorption energy of metal adatoms across the graphene sheet directs the assembly of NCs to a periodic array of thermodynamically preferred locations. The modeling describes not only just the NC densities and size distributions, but also the composition distribution for mixed NCs. A strong dependence of these quantities on the deposition order is primarily related to different effective mobilities of Pt and Ru on the supported graphene.
Preparation of Y0.5Bi2.5Fe5O12 films on glass substrates using magnetic iron garnet buffer layers by metal-organic decomposition method
Authors: Ishibashi Takayuki , Yoshida Tomohiko , Kobayashi Tsukasa , Ikehara Shigehiro , Nishi Takao
Published: April 2013

Y0.5Bi2.5Fe5O12 (Bi2.5:YIG) films were prepared on glass substrates by metal-organic decomposition method. Bi2.5:YIG films were grown on buffer layers of Y2BiFe5O12, Gd2BiFe5O12, or Nd2BiFe4GaO12 (Nd-buffer layer) prepared on the glass substrates, while it was not obtained without buffer layers. It was found that Bi2.5:YIG films on Nd-buffer layer had a good crystallinity and large Faraday rotation of 13.8°/μm at 520 nm in wavelength.
A pencil-like magnetoelectric sensor exhibiting ultrahigh coupling properties
Authors: Lin Lizhi , Li Yingwei , Soh Ai-Kah , Li Faxin
Published: April 2013

A one-dimensional pencil-like magnetoelectric (ME) sensor prototype is proposed which consists of a magnetostrictive cylinder, a truncated conical spacer, and a piezoelectric disk assembled in a rigid frame. By adopting the displacement-transfer mode in this sensor, not only the strain loss at the ME interface is avoided but also the volume fractions of both phases can be adjusted in a broader range. Using a nonlinear magnetostrictive model and linear piezoelectric model, the ME coupling performance of this sensor is systematically analyzed using lead titanate zirconate (PZT) disks and Terfenol-D cylinder as the components. Results show that such a sensor can practically exhibit giant quasi-static ME field coefficients (αE) and charge density coefficients (αD) as high as 455 V/cm Oe and 480×10−6 C/m2 Oe, which is about 10 times and 100 times higher than the best reported values, respectively. Furthermore, the ME coupling properties will decrease considerably when the stiffness of the frame is reduced. The proposed pencil-like ME sensor in this work could be very helpful in the design of ultrasensitive magnetic-field sensors and other ME coupling devices.
Thermal-wave fields in solid wedges using the Green function method: Theory and experiment
Authors: Tai Rui , Zhang Jie , Wang Chinhua , Mandelis Andreas
Published: April 2013

In this work, we establish a theoretical model for a cylindrical rod of radius R with opening angle θ illuminated by a modulated incident beam. The model uses the Green function method in cylindrical coordinates. An analytical expression for the Green function and thermal-wave field in such a solid is presented. The theory is validated in the limit of reducing the arbitrary wedge geometrical structure to simpler geometries. For acute angle wedges, it is shown that the thermal-wave field near the edge exhibits confinement behavior and increased amplitude compared to a flat (reference) solid with θ = π. For obtuse angle wedges, it is shown that the opposite is true and relaxation of confinement occurs leading to lower amplitude thermal-wave fields. The theory provides a basis for quantitative thermophysical characterization of wedge-shaped objects and it is tested using an AISI 304 steel wedge and photothermal radiometry detection.
Effects of crystal defects and their interactions with impurities on electrical properties of multicrystalline Si
Authors: Joonwichien Supawan , Matsushima Satoru , Usami Noritaka
Published: April 2013

We investigated the effects of different crystal defects and their interactions with impurities on the electrical properties of multicrystalline Si (mc-Si) using samples with unique defect patterns and impurities. By using the floating cast method, a single grain boundary (GB), identified as a Σ27 boundary, was first formed with a high density of impurities from atmosphere, leading to an inefficient external gettering of impurities during phosphorus (P) diffusion. During crystal growth, the Σ27 GB splits into the Σ3 and Σ9 GBs with accompanying generation of dislocations and reduction in the density of impurities. The external gettering of impurities became efficient for removing impurities as evidenced by an increase in average minority carrier lifetime. At the final stage of crystal growth, the decrease in minority carrier lifetime was significant, which could not be improved by phosphorus diffusion because of the high densities of segregated impurities and crystal defects originating from the strong contact with the crucible. The increase in Σ number was found to result in more enhanced precipitation of impurities, which led to the poor gettering effect of P diffusion. These results further confirmed the importance of the reduction in the densities of impurities and dislocations for the quality and yield improvement of mc-Si ingots for solar cells.
Magnetic properties of ferrite-titanate nanostructured composites synthesized by the polyol method and consolidated by spark plasma sintering
Authors: Acevedo Ulises , Gaudisson Thomas , Ortega-Zempoalteca Raul , Nowak Sophie , Ammar Souad , Valenzuela Raul
Published: April 2013

Multiferroic systems formed by a mixing of a ferroelectric phase and a ferrimagnetic phase are receiving significant attention because of their wide possibilities for tailoring properties. In this work, the magnetic properties of the cobalt ferrite-barium titanate system were investigated on samples prepared by an original combination of synthesis methods. Cobalt ferrite and barium titanate nanoparticles were synthesized separately by hydrolysis of the metal acetates in a polyol method. Both materials were mixed in a 1:1 ratio and consolidated by spark plasma sintering at 500 °C for 5 min. A high density nanostructured ceramic was obtained with grains smaller than 100 nm and a density about 80% of the theoretical value. Magnetic hysteresis loops showed a hard magnet behavior, with a coercive field larger than cobalt ferrite alone prepared under the same conditions. δM reversible magnetization plots exhibited dipolar interactions with a maximum at the coercive field. These results are interpreted in terms of an efficient mixing of the components, which strongly decreases the magnetic percolation in the composite by separating ferrite grains by titanate grains.
Effects of (P, N) dual acceptor doping on band gap and p-type conduction behavior of ZnO films
Authors: Sui Yingrui , Yao Bin , Xiao Li , Xing Guozhong , Yang Lili , Li Xuefei , Li Xiuyan , Lang Jihui , Lv Shiquan , Cao Jian , Gao Ming , Yang Jinghai
Published: April 2013

A reproducible p-type P-N codoped ZnO [ZnO:(P, N)] film with high quality was achieved by magnetron sputtering and post-annealing techniques. It has room-temperature resistivity of 3.98 Ωcm, Hall mobility of 1.35 cm2/Vs, and carrier concentration of 1.16 × 1018 cm−3, which is better than electrical properties of the p-type N-doped ZnO (ZnO:N) and p-type P-doped ZnO (ZnO:P) films. Additionally, the p-ZnO:(P, N)/n-ZnO homojunction showed a clear p-n diode characteristic. The p-type conductivity of ZnO:(P, N) is attributed to the formation of an impurity band above the valance band maximum, resulting in a reduction in the band gap and a decrease in the ionization energy of the acceptor, as well as an improvement in the conductivity and stability of the p-type ZnO:(P, N).
Evidence of a Griffiths phase in a mixed compound of YFe2 and YFe3
Authors: Öner Y. , Guler A.
Published: April 2013

Experimental evidence of a Griffiths phase is still a challenging topic in condensed matter physics. We show that a mixed compound of YFe2 and YFe3 is an archetype example of Griffiths-like behavior. We report magnetization measurements carried out on the intermetallic mixed compound of YFe2 and YFe3 in the temperature range of 10-1000 K and using magnetic fields up to 23 T. The low-field dc magnetic susceptibility (χ = M/H) showed a thermomagnetic irreversibility effect below the Curie temperatures, TC = 526 K for YFe3 and TC = 545 K for YFe2. Specifically, we found that upon field-cooling (FC), the magnetization increased gradually with decreasing temperature and then reached a saturation value at a critical temperature. In contrast, the zero-FC measurements showed a much more complicated behavior. This behavior has been interpreted in terms of two canted sublattices coupled ferromagnetically. Furthermore, for temperatures above TC, the inverse susceptibility, χ−1, shows a clear downturn, exhibiting non-universal behavior for magnetic fields up to 1 T. This anomaly is characteristic of non-universal Griffiths like behavior. Using the equation for the magnetic susceptibility for the Griffiths phase, χ−1=C(T-TCM)1−λ, we obtained the non-universal prefactor exponent, λ, and the other fitting parameter for each measuring field. The isothermal magnetization curve at Curie temperature, TC = 545 K obeys perfectly M ∼ Hα, from which the critical exponent α = 1/δ is determined accurately. All these results closely follow the predictions for Griffiths phase. In our scenerio, the YFe3 regions (TC = 526 K) distributed homogeneously in the matrix are quenched by the demagnetizing fields of YFe2 (TC = 545 K) as the temperature increases, leading to ordered Fe regions, which in turn cause the Griffiths effect.
An Al@Al2O3@SiO2/polyimide composite with multilayer coating structure fillers based on self-passivated aluminum cores
Authors: Zhou Yongcun , Wang Hong
Published: April 2013

We demonstrate a capability in combining two kinds of nanosize and microsize particles of core-shell Al@Al2O3@SiO2 with aluminum cores to form multilayer coating structures as fillers in polyimide matrix for electronic applications. The core-shell Al@Al2O3@SiO2 structure can effectively adjust the relative permittivity (about 12 @1 MHz) of the composite while keeping lower dielectric loss (0.015 @1 MHz) compared to that uncoated aluminum particles. The combination of “macro” and “micro” coating can significantly improve the dielectric properties of the composites. This work provides a useful method to modify the fillers for polymer matrix nanocomposite materials.
The augmented saddle field discharge characteristics and its applications for plasma enhanced chemical vapour deposition
Authors: Wong Johnson , Yeghikyan Davit , Kherani Nazir P.
Published: April 2013

A high ion flux parallel electrode plasma is proposed and studied in its DC configuration. By cascading a diode source region which supplies electrons and a saddle field region where these seed electrons are energized and amplified, the energy of ion bombardment on the substrate can be decoupled from the plasma density. The sufficiently large density of electrons and holes in the vicinity of the substrate raises the possibility to perform plasma enhanced chemical vapour deposition on insulating materials, at low sheath voltages (around 40 V in the configuration studied), at low temperatures in which the surface mobility of film growth species may be provided by the bombardment of moderate energy ions. As a benchmarking exercise, experiments are carried out on silane discharge characteristics and deposition of hydrogenated amorphous silicon (a-Si:H) on both silicon wafer and glass. The films grown at low anode voltages have excellent microstructures with predominantly monohydride bonds, sharp band tails, but relatively high integrated defect density in the mid 1016/cm3 range for the particular substrate temperature of 180 °C, indicating that further optimizations are necessary if the electrode configuration is to be used to create a-Si:H devices.
Large band gaps in two-dimensional phononic crystals with neck structures
Authors: Yu Kunpeng , Chen Tianning , Wang Xiaopeng
Published: April 2013

In this paper, we study the band gap properties of a two-dimensional phononic crystal composed of periodic cylinders embedded in a homogenous matrix. The cylinders are not connected with the matrix directly but linked with it through the neck structures constituted by part of a circle. The dispersion relations, transmission spectra, and displacement fields of the eigenmodes of this phononic crystal are studied using the finite-element method. In contrast to the typical phononic crystals where the cylinders and matrix are in contact completely, the proposed structures with necks display larger band gaps at lower frequencies. The reason for the occurrence of the low-frequency band gaps as well as the effects of the geometrical parameters of the neck structures on the gaps are further explored numerically. Results show that the openings of the band gaps are attributed to the resonance of the cylinders and the interaction between the cylinders and the matrix, resulting from the introduction of the necks. The band gaps are significantly dependent upon the geometrical parameters such as the rotation angle of the necks which is defined as the angle between the centerline of the neck and the x-axis, the arc length of the necks, and also the filling ratio of the inclusions. The study in this paper is relevant to the design of tuning band gaps and isolators in the low-frequency range.
Charge carrier dynamics in bulk MoS2 crystal studied by transient absorption microscopy
Authors: Kumar Nardeep , He Jiaqi , He Dawei , Wang Yongsheng , Zhao Hui
Published: April 2013

We report a transient absorption microscopy study of charge carrier dynamics in bulk MoS2 crystals at room temperature. Charge carriers are injected by interband absorption of a 555-nm pulse, and probed by measuring differential reflection of a time-delayed and spatially scanned 660-nm pulse. We find an intervalley transfer time of about 0.35 ps, an energy relaxation time of hot carriers on the order of 50 ps, and a carrier lifetime of 180 ± 20 ps. By monitoring the spatiotemporal dynamics of carriers, we obtained a diffusion coefficient of thermalized electrons of 4.2 ± 0.5 cm2/s, corresponding to a mobility of 170 ± 20 cm2/Vs. We also observed a time-varying diffusion coefficient of hot carriers.
Nematic twist cell: Strong chirality induced at the surfaces
Authors: Lin Tzu-Chieh , Nemitz Ian R. , Pendery Joel S. , Schubert Christopher P. J. , Lemieux Robert P. , Rosenblatt Charles
Published: April 2013

A nematic twist cell having a thickness gradient was filled with a mixture containing a configurationally achiral liquid crystal (LC) and chiral dopant. A chiral-based linear electrooptic effect was observed on application of an ac electric field. This “electroclinic effect” varied monotonically with d, changing sign at d=d0 where the chiral dopant exactly compensated the imposed twist. The results indicate that a significant chiral electrooptic effect always exists near the surfaces of a twist cell containing molecules that can be conformationally deracemized. Additionally, this approach can be used to measure the helical twisting power (HTP) of a chiral dopant in a liquid crystal.
Generation of 500 MeV–1 GeV energy electrons from laser wakefield acceleration via ionization induced injection using CO2 mixed in He
Authors: Mo M. Z. , Ali A. , Fourmaux S. , Lassonde P. , Kieffer J. C. , Fedosejevs R.
Published: April 2013

Laser wakefield acceleration of 500 MeV to 1 GeV electron bunches has been demonstrated using ionization injection in mixtures of 4% to 10% of CO2 in He. 80 TW laser pulses were propagated through 5 mm gas jet targets at electron densities of 0.4−1.5×1019cm−3. Ionization injection led to lower density thresholds, a higher total electron charge, and an increased probability of producing electrons above 500 MeV in energy compared to self-injection in He gas alone. Electrons with GeV energies were also observed on a few shots and indicative of an additional energy enhancement mechanism.
An analytical approach to the interaction of a propagating spin wave and a Bloch wall
Authors: Wang Xi-guang , Guo Guang-hua , Zhang Guang-fu , Nie Yao-zhuang , Xia Qing-lin
Published: April 2013

The spin wave propagation and the spin-wave induced domain wall motion in a nanostrip with a Bloch domain wall are studied. The spin-wave dispersion relation and the transmission coefficients across the wall are derived analytically. A one-dimensional model for the domain wall motion is constructed. It is found that the spin wave can drive the wall to move either in the same direction or in the opposite direction to that of spin-wave propagation depending on the transmission coefficient. The transmitted magnons drag the wall moving backward without inertia by the adiabatic and nonadiabatic spin-transfer torques, while the reflected magnons push the wall moving forward by the linear momentum transfer torque.
Enhanced thermal stability and electrical behavior of Zn-doped Sb2Te films for phase change memory application
Authors: Shen Xiang , Wang Guoxiang , Wang R. P. , Dai Shixun , Wu Liangcai , Chen Yimin , Xu Tiefeng , Nie Qiuhua
Published: April 2013

Zn-doped Sb2Te films are proposed to present the feasibility for phase-change memory application. Zn atoms are found to significantly increase crystallization temperature of Znx(Sb2Te)1−x films and be almost linearly with the wide range of Zn-doping concentration from x = 0 to 29.67 at.%. Crystalline resistances are enhanced by Zn-doping, while keeping the large amorphous/crystalline resistance ratio almost constant at ∼105. Especially, the Zn26.07(Sb2Te)73.93 and Zn29.67(Sb2Te)70.33 films exhibit a larger resistance change, faster crystallization speed, and better thermal stability due to the formation of amorphous Zn-Sb and Zn-Te phases as well as uniform distribution of Sb2Te crystalline grains.
Optical rotatory power of polymer-stabilized blue phase liquid crystals
Authors: Liu Yifan , Lan Yi-fen , Zhang Hongxia , Zhu Ruidong , Xu Daming , Tsai Cheng-Yeh , Lu Jen-Kuei , Sugiura Norio , Lin Yu-Chieh , Wu Shin-Tson
Published: April 2013

Macroscopically, a polymer-stabilized blue phase liquid crystal (BPLC) is assumed to be an optically isotropic medium. Our experiment challenges this assumption. Our results indicate that the optical rotatory power (ORP) of some nano-scale double-twist cylinders in a BPLC composite causes the polarization axis of the transmitted light to rotate a small angle, which in turn leaks through the crossed polarizers. Rotating the analyzer in azimuthal direction to correct this ORP can greatly improve the contrast ratio. A modified De Vries equation based on a thin twisted-nematic layer is proposed to explain the observed phenomena.
Niobium nitride-based normal metal-insulator-superconductor tunnel junction microthermometer
Authors: Chaudhuri S. , Nevala M. R. , Maasilta I. J.
Published: April 2013

We have fabricated Cu-AlOx-Al-NbN normal metal-insulator-superconductor (NIS) tunnel junction devices, using pulsed laser deposition (PLD) for NbN film growth, and electron-beam lithography and shadow evaporation for the final device fabrication. The subgap conductance of these devices exhibits a strong temperature dependence, rendering them suitable for thermometry from ∼0.1 K all the way up to the superconducting transition temperature of the NbN layer, which was here ∼11 K, but could be extended up to ∼16 K in our PLD chamber. Our data fit well to the single particle NIS tunnel junction theory, with an observed proximized superconducting gap value ∼1 meV for a 40 nm thick Al overlayer. Although this high value of the superconducting energy gap is promising for potential electronic NIS cooling applications as well, the high value of the tunneling resistance inhibits electronic cooling in the present devices. Such opaque barriers are, however, ideal for thermometry purposes as self-induced thermal effects are thus minimized.
Learners’ search patterns during corpus-based focus-on-form activities
Authors: Pérez-Paredes Pascual , Sánchez-Tornel María , Calero Jose M. Alcaraz
Published: March 2013

Our research explores the search behaviour of EFL learners (n=24) by tracking their interaction with corpus-based materials during focus-on-form activities (Observe, Search the corpus, Rewriting). One set of learners made no use of web services other than the BNC during the central Search the corpus activity while the other set resorted to other web services and/or consultation guidelines. The performance of the second group was higher, the learners’ formulation of corpus queries on the BNC was unsophisticated and the students tended to use the BNC search interface to a great extent in the same way as they used Google or similar services. Our findings suggest that careful consideration should be given to the cognitive aspects concerning the initiation of corpus searches, the role of computer search interfaces, as well as the implementation of corpus-based language learning. Our study offers a taxonomy of learner searches that may be of interest in future research.
Identifying and intensifying uses of prenominal such
Authors: Ghesquière Lobke
Published: March 2013

In this article, I revisit the functional distinction between identifying and intensifying uses of such, as in such a person and such a blunderer respectively. In the literature on such, attention has gone mainly to its classification in terms of word class and position in the NP, and to the different NP-structures it occurs in. This paper adopts a data-based constructional approach of cognitive-functional affiliation, viewing grammatical and lexical syntagmatic patterning as one continuum. It offers a fine-grained description of the identifying and intensifying functions of such by observing their different scopal relations, and grammatical and collocational co-occurrence patterns in the data. It also makes a data-based contribution to the controversy about contexts that are vague between an identifying and intensifying reading. The distributional patterns of identifying, intensifying and vague uses of such in spoken and written contemporary corpus data are quantified and interpreted in terms of genre distinctions.
Self-Reference in biomedical research article discussions
Authors: Williams Ian A.
Published: March 2013

The aim of this quantitative and qualitative study is to compare inclusive and exclusive self-reference in a bilingual English-Spanish corpus of biomedical research articles. The study combines corpus techniques with move analysis to determine where authors resort to first-person reference in Discussion sections. Quantitative analysis showed that Spanish writers selected between exclusive and mixed inclusive-exclusive perspectives equally whereas the exclusive perspective predominated in the English-language articles. Major differences between languages were observed for overall use and for statements of results, comparison of current and previous findings, and metatext. From a cross-disciplinary viewpoint, biomedical research articles exhibited less self-promotion than previously reported for biology. Qualitative analysis revealed that first-person verbs in English were frequently associated with self-promotion whereas English possessives and all exclusive use in Spanish served to attribute responsibility for statements and to harmonise the multiple voices in the polyphonic discourse of biomedical Discussions. The study provides further evidence for cross-cultural and cross-disciplinary diversity in academic and scientific discourse.
Global analysis of SUMO chain function reveals multiple roles in chromatin regulation
Authors: Srikumar Tharan , Lewicki Megan C. , Costanzo Michael , Tkach Johnny M. , van Bakel Harm , Tsui Kyle , Johnson Erica S. , Brown Grant W. , Andrews Brenda J. , Boone Charles , Giaever Guri , Nislow Corey , Raught Brian
Published: April 2013

Like ubiquitin, the small ubiquitin-related modifier (SUMO) proteins can form oligomeric “chains,” but the biological functions of these superstructures are not well understood. Here, we created mutant yeast strains unable to synthesize SUMO chains (smt3allR) and subjected them to high-content microscopic screening, synthetic genetic array (SGA) analysis, and high-density transcript profiling to perform the first global analysis of SUMO chain function. This comprehensive assessment identified 144 proteins with altered localization or intensity in smt3allR cells, 149 synthetic genetic interactions, and 225 mRNA transcripts (primarily consisting of stress- and nutrient-response genes) that displayed a >1.5-fold increase in expression levels. This information-rich resource strongly implicates SUMO chains in the regulation of chromatin. Indeed, using several different approaches, we demonstrate that SUMO chains are required for the maintenance of normal higher-order chromatin structure and transcriptional repression of environmental stress response genes in budding yeast.
Aurora A is involved in central spindle assembly through phosphorylation of Ser 19 in P150Glued
Authors: Reboutier David , Troadec Marie-Bérengère , Cremet Jean-Yves , Chauvin Lucie , Guen Vincent , Salaun Patrick , Prigent Claude
Published: April 2013

Knowledge of Aurora A kinase functions is limited to premetaphase events, particularly centrosome maturation, G2/M transition, and mitotic spindle assembly. The involvement of Aurora A in events after metaphase has only been suggested because appropriate experiments are technically difficult. We report here the design of the first human Aurora A kinase (as-AurA) engineered by chemical genetics techniques. This kinase is fully functional biochemically and in cells, and is rapidly and specifically inhibited by the ATP analogue 1-Naphthyl-PP1 (1-Na-PP1). By treating cells exclusively expressing the as-AurA with 1-Na-PP1, we discovered that Aurora A is required for central spindle assembly in anaphase through phosphorylation of Ser 19 of P150Glued. This paper thus describes a new Aurora A function that takes place after the metaphase-to-anaphase transition and a new powerful tool to search for and study new Aurora A functions.
Aneuploidy in health, disease, and aging
Authors: Ricke Robin M. , van Deursen Jan M.
Published: April 2013

Aneuploidy, an aberrant number of chromosomes, has been recognized as a feature of human malignancies for over a century, but compelling evidence for causality was largely lacking until mouse models for chromosome number instability were used. These in vivo studies have not only uncovered important new insights into the extremely complex aneuploidy–cancer relationship but also into the molecular mechanisms underlying proper and aberrant chromosome segregation. A series of diverse mouse models for the mitotic checkpoint protein BubR1 has provided evidence for a provocative novel link between aneuploidization and the development of age-related pathologies.
Online scholarly publishing in China: Who? What? How?
Authors: Jie XU , Xiaoqun YUAN
Published: March 2013

This overview describes the general situation of online scholarly publishing in China from both the supply and demand points of view. Based on desk research, online survey, and face‐to‐face interviews, we identify scholars' perceptions as well as expectations of the current online publishing system. We offer some personal recommendations for change. We then provide a list of business models for stakeholders.
Ranking journals: could Google Scholar Metrics be an alternative to Journal Citation Reports and Scimago Journal Rank?
Authors: DELGADO‐LÓPEZ‐CÓZAR Emilio , CABEZAS‐CLAVIJO Álvaro
Published: March 2013

The launch of Google Scholar Metrics as a tool for assessing scientific journals may be serious competition for Thomson Reuters' Journal Citation Reports, and for the Scopus‐powered Scimago Journal Rank. A review of these bibliometric journal evaluation products is performed. We compare their main characteristics from different approaches: coverage, indexing policies, search and visualization, bibliometric indicators, results analysis options, economic cost, and differences in their ranking of journals. Despite its shortcomings, Google Scholar Metrics is a helpful tool for authors and editors in identifying core journals. As an increasingly useful tool for ranking scientific journals, it may also challenge established journals products.
Simplifying e‐book and print production
Authors: BORGSTROM Liam
Published: March 2013

While XML‐based single‐source publishing is a powerful tool for streamlining the book publishing industry, it may not be the right one for every sector of the industry. For an industry that is part cultural and part industrial, the traditional workflow allows for creativity at every stage and this craft focus still deserves a place in defining how the industry functions. With simple and familiar tools, it can be possible to integrate elements of old and new principles to create a workflow that is streamlined and advantageous without being too radical a shift in practice. This article describes the factors that are important to creating publications in both digital and physical formats.
Information workflow of academic researchers in the evolving information environment: an interview study
Authors: NEWMAN Michael L. , SACK John
Published: March 2013

Digital journals have been widely adopted by academic researchers and have nearly replaced printed journals in many contexts. The adoption of digital books is accelerating. The transition to digital information has changed information workflows of researchers by transforming the methods they use to find, store, retrieve, and use information from monographs, journals, and other sources. It has also changed the needs and expectations of scholars in relation to research information. To investigate these changes, 45 researchers in science, medicine, engineering, social sciences, and humanities at Stanford University were interviewed regarding information workflow and preferences. Results are compared with the findings of the e‐Journal User Study (eJUSt), completed in 2002.
Market‐oriented reform in Chinese scholarly publishing
Authors: Qing FANG , Lifang XU
Published: March 2013

The Chinese government initiated a policy of 'corporatization of cultural entities' in 2003. Most Chinese book publishing houses were required to complete this transformation by 2006 and journal publishers by 2012. Chinese academic publishers, who no longer receive any general subsidies and allowances from government, have struggled to survive since then. During the reform process, many Chinese journals charged their authors page fees, and academic book publishers raised the prices of their publications. The continuing existence of other subsidies, however, means that there is still a degree of dependency in the Chinese system, and it will take time for its academic publishers to grow into real market players and to enhance their competitiveness.
Understanding the needs of international authors
Authors: MUDRAK Benjamin
Published: March 2013

Research and scholarly publication are global endeavors, and English‐language journals are receiving more and more manuscript submissions from international authors. A better understanding of the challenges faced by researchers who are not native English speakers will enable journal publishers to improve the process of submission for all authors, ensuring that the best papers are published in an efficient manner. We surveyed a sample of international researchers to determine what they perceived as challenges inherent to submission to English‐language journals and found that they desire assistance with manuscript formatting and responding to reviewers, as well as clear policies about pre‐submission inquiries and conflicts of interest. Taking into account these survey results and the experience our company has with international authors, we suggest several small changes to a journal's website, including clearer English and prominent links to select policies and guidelines, that may greatly simplify the submission process for second language authors.
Book reviews
Authors: SMART Pippa
Published: March 2013

The Information Diet: A Case for Conscious Consumption Clay Johnson O'Reilly, 2011, 150pp. ISBN 978‐1‐449‐30468‐3, £11.20 hbk www.informationdiet.com
Book reviews
Authors: BALKWILL Richard
Published: March 2013

Essential Law for Information Professionals, 3rd edn Paul Pedley London, Facet Publishing, 2011, 368pp. ISBN 978‐1‐85604‐769‐2, £49.95
Book reviews
Authors: GUNTER Darrell W.
Published: March 2013

Social Media for Academics – A Practical Guide Diane Rasmussen Neal Oxford, Chandos Publishing, 2012, 232pp. ISBN 978‐1‐84334‐681‐4 (print), 978‐1‐78063‐319‐0 (online), £49.50/US$85.00/€60.00
Fast simulation of reconstructed phylogenies under global time-dependent birth–death processes
Authors: Höhna Sebastian
Published: March 2013

Motivation: Diversification rates and patterns may be inferred from reconstructed phylogenies. Both the time-dependent and the diversity-dependent birth–death process can produce the same observed patterns of diversity over time. To develop and test new models describing the macro-evolutionary process of diversification, generic and fast algorithms to simulate under these models are necessary. Simulations are not only important for testing and developing models but play an influential role in the assessment of model fit.

Results: In the present article, I consider as the model a global time-dependent birth–death process where each species has the same rates but rates may vary over time. For this model, I derive the likelihood of the speciation times from a reconstructed phylogenetic tree and show that each speciation event is independent and identically distributed. This fact can be used to simulate efficiently reconstructed phylogenetic trees when conditioning on the number of species, the time of the process or both. I show the usability of the simulation by approximating the posterior predictive distribution of a birth–death process with decreasing diversification rates applied on a published bird phylogeny (family Cettiidae).

Availability: The methods described in this manuscript are implemented in the R package TESS, available from the repository CRAN (http://cran.r-project.org/web/packages/TESS/).

Contact:  hoehna@math.su.se

Supplementary information:  Supplementary data are available at Bioinformatics online.
First Report of Tobacco ringspot virus Infecting Ajuga reptans in Ohio
Authors: Fisher John R.
Published: April 2013

In the fall of 2011, a bugleweed sample tested positive for Tobacco ringspot virus (TRSV). Immunocapture RT-PCR using cDNAs from bound virions with RNA-dependent RNA polymerase (RdRp) and coat protein (CP) specific primers both amplified strong, distinct products. Cloned RdRp and CP amplicons were 89% and 97% identical, respectively, to GenBank accessions U50869.1 and AY363727.1, respectively. These results represent the first confirmed report of TRSV infecting Ajuga reptans in Ohio.

Accepted for publication 11 January 2012. Published 1 March 2013.
Identification of Soybean Accessions Resistant to Macrophomina phaseolina by Field Screening and Laboratory Validation
Authors: Mengistu Alemu , Arelli Prakash , Bond Jason , Nelson Randall , Rupe John , Shannon Grover , Wrather Allen
Published: April 2013

Charcoal rot of soybean, caused by Macrophomina phaseolina (Tassi) Goidanich, has been a problem for soybean farmers in the United States for many years. However, recently its incidence and severity has increased in midwestern and north-central states. Most management strategies, including chemical and biological methods and other cultural options, have been ineffective in controlling this disease. Furthermore, soybean is often planted every other year or in monoculture. Although genetic resistance would be the most sustainable control strategy, resistant commercial soybean cultivars are presently unavailable. The objective of this test was to identify resistant accessions from the USDA soybean germplasm collection in Maturity Groups (MG) 00 to VII by field screening in five environments. A total of 628 accessions were evaluated using established methods for reaction to this disease in Missouri and Illinois (2008 to 2009), and in Tennessee (2009). In 2010, accessions with disease severity reactions of 1 to ≤ 2 were selected for further evaluation in Tennessee. Among the 45 accessions identified as resistant and moderately resistant (1 to ≤ 2), ten were further assessed using colony forming units recovered from ground root and stem tissues which was then converted to colony forming unit index (CFUI) and validated their resistance using this bioassay. All ten had CFUI levels ranging from 0 to 18.2, which were significantly lower (P ≤ 0.05) than the moderately resistant accession, DT97-4290, with 31.8. Four selected accessions, PI594302 (MG VII), PI567562A (MG IV), PI506764 (MG VII), and PI567334 (MG VI), had significantly lower (P ≤ 0.05) CFUI of 0, 0.8, 0.8, and 1.5, respectively. This is the first report of soybean accessions with better levels of resistance than the standard released germplasm, DT97-4290. These accessions can serve as additional sources of charcoal rot resistance in future breeding programs.

Accepted for publication 20 January 2013. Published 18 March 2013.
Preparation and Use of Reporter Constructs for Imaging Morphogenesis in Xenopus Embryos
Authors: Kim Hye Young , Davidson Lance A.
Published: April 2013

To understand dynamic cell and tissue mechanics during Xenopus laevis morphogenesis requires the use of live reporters of cell architecture as well as reporters for the location and activity of proteins in cells within a multicellular tissue. Fluorescently tagged proteins are some of the most useful reporters for live cell work. These fluorescent reporters are either proteins conjugated to small fluorochromes or molecularly engineered chimeric fluorescent proteins, and they can be distributed evenly across a tissue or localized within a subset of cells. An evenly distributed reporter is useful when visualizing patterns of protein localization within a field of cells. Alternatively, restricting the expression of a reporter to single cells or patches of cells in a mosaic can reveal patterns of subcellular localization. Here we discuss methods for synthesizing mRNA encoding fluorescent proteins and for expressing these proteins evenly as well as in scattered populations within a multicellular tissue.
Assembly of Chambers for Stable Long-Term Imaging of Live Xenopus Tissue
Authors: Kim Hye Young , Davidson Lance A.
Published: April 2013

Understanding the molecular mechanisms and cellular mechanics that drive morphogenesis in Xenopus laevis embryos requires high-resolution quantitative imaging of cell movement and protein dynamics within multicellular tissues. To perform long-term tissue culture and stable imaging of live Xenopus tissue, we have developed a simple acrylic chamber that can be sealed and reused. The explants can be cultured on an adhesive substrate or within a nonadhesive microenvironment. We have developed a method for sandwiching isolated marginal zone (MZ) explants between thin agarose sheets. To manipulate the stiffness of the substrate or to measure cell traction generated by cells in an intact tissue, a fibronectin-conjugated polyacrylamide gel (FN-PAG) substrate can be used. The mechanical properties of this substrate can be easily modulated by varying the ratio of acrylamide to bis-acrylamide and the transparent nature of the PAG can allow observation of intracellular dynamics through the gel. Cell tractions are detected by following movements of fluorescent beads embedded in the gel.
Measuring Angiogenesis and Hemodynamics in Mice
Authors: Jain Rakesh K. , Munn Lance L. , Fukumura Dai
Published: April 2013

This protocol outlines methods to measure vascular parameters, including angiogenesis (e.g., vascular density, length, diameter) and hemodynamics (e.g., erythrocyte velocity), in tumors and normal vascular networks in mice. Fluorescein-isothiocyanate (FITC)-dextran is injected into the tail vein of mice to visualize microvessels within 150 μm (using single-photon microscopy) or ∼600 μm (using multiphoton laser-scanning microscopy [MPLSM]) of a tumor/window interface. Randomly selected areas (three to six locations/tumor or animal) are investigated using long-working-distance objectives with appropriate magnification. During each observation period, FITC-fluorescence images are recorded for 60 sec, and the videotapes are analyzed off-line for single-photon microscopy; or a three-dimensional (3D) image stack of the vessel network is generated, and vessel properties are measured for MPLSM. If desired, red blood cell (RBC) flux can be measured on a vessel-by-vessel basis using fluorescent tracer RBCs.
Calcium-Sensitive Mini- and Microelectrodes
Authors: Thomas Roger C. , Bers Donald M.
Published: April 2013

It is widely agreed that the best method for measuring the ionized free calcium concentration ([Ca2+]) in large volumes of biological solutions is to use Ca2+-sensitive macroelectrodes. These are commercially available. To measure [Ca2+] in small volumes of solution, minielectrodes with 1–2-mm tips can easily be made and used, and may also be commercially available. Ca2+-sensitive microelectrodes (CaSMs, with 0.5–2-μm tips) can also be made and used extracellularly or intracellularly in robust cells, but interest in their use has recently been largely eclipsed. This is because of practical difficulties and the introduction of a large number of fluorescent and other optical calcium probes with calcium sensitivities varying from the nanomolar to the millimolar range, such as Fura-2, Indo-1, Fluo-4, and many others. In this article, we emphasize the utility of Ca2+-selective electrodes and show that their use is complementary to use of fluorescent and other optical methods. Each method has advantages and disadvantages. Because numerous reviews and books have been dedicated to the theoretical aspects of ion-selective electrode principles and technology, this article is mainly intended for investigators who have some degree of electrophysiological experience with ion-selective electrodes or microelectrodes.
Purification and Culture of Spinal Motor Neurons
Authors: Graber David J. , Harris Brent T.
Published: April 2013

Motor neurons are responsible for voluntary movement. Lower motor neurons are characterized by large soma, the potential to form very long axons, and wide-ranging dendritic arborization. They receive direction from various neuronal cell types and induce movement of skeletal muscle fibers through acetylcholine release at the neuromuscular junction. Each lower motor neuron can communicate with 10 to several hundred muscle fibers at firing rates modulated by the balance of ongoing neurotransmitter signaling. Disease and trauma that affect lower motor neurons can cause paralysis and, in some cases, death. Studies using primary cultures of these cells have ongoing potential to facilitate a deeper understanding of their biology and function.
Two novel lead(II) complexes of 2-(hydroxymethyl)pyridine: a threefold diamondoid supramolecular network based on Pb4O4cores and a two-dimensional (4,4) network based on Pb2O2units
Authors: Liu Ting , Pan Yu-Peng , Wang Suna , Dou Jian-Min
Published: March 2013

Reactions of 2-(hydroxymethyl)pyridine (Hhmp) with PbCl2and Pb(NO3)2at room temperature led to the formation of two novel compounds, namely tetrakis[μ3-(pyridin-2-yl)methanolato]-tetrahedro-tetrakis[chloridolead(II)], [Pb4(C6H6NO)4Cl4], (I), and poly[(μ2-nitrato)[μ2-(pyridin-2-yl)methanolato]lead(II)], [Pb(C6H6NO)(NO3)]n, (II). Compound (I) exhibits a tetranuclear Pb4O4cubane structure, which is connected through π–π stacking interactions between the pyridine groups of the (pyridin-2-yl)methanolate (hmp−) ligands and through C—H...Cl interactions to form an interesting threefold diamondoid network. Compound (II) possesses two-dimensional (4,4)-sql topology based on a Pb2O2unit, which is further extended into a three-dimensional supramolecular network through π–π stacking interactions between adjacent pyridine rings and through C—H...O interactions between the pyridine C atoms of the hmp−ligands and the nitrate anions.
CEO Compensation and Fair Value Accounting: Evidence from Purchase Price Allocation
Authors: SHALEV RON , ZHANG IVY XIYING , ZHANG YONG
Published: April 2013

This study investigates the impact of CEO compensation structure on post‐acquisition purchase price allocation, an accounting procedure that involves fair value estimation of various assets and liabilities. We find that CEOs whose compensation packages rely more on earnings‐based bonuses are more likely to overallocate the purchase price to goodwill, the largest asset recorded post‐acquisition. Because goodwill is not amortized, the overallocation likely increases post‐acquisition earnings and bonuses. We also find that, when the acquirer's CEO bonus plan includes performance measures that are not affected, or are less affected, by the overstatement of goodwill, such as cash flows, sales, or earnings growth, the overallocation to goodwill motivated by bonus plans diminishes.
The economic impacts of tourism in Botswana, Namibia and South Africa: Is poverty subsiding?
Authors: Muchapondwa Edwin , Stage Jesper
Published: April 2013

Tourism in southern Africa is based on the region's wildlife and nature assets and is generally environmentally sustainable, but the extent to which it contributes to other aspects of sustainable development — overall income generation or poverty eradication — is less well explored. In this paper, we use social accounting matrices to compare the economic impacts of foreign tourism in Botswana, Namibia and South Africa. Overall impacts on GDP range from 6% (South Africa) to 9% (Namibia). However, South Africa's economy is more diversified than its neighbours' and more of the goods and services used by tourists and by the tourism industry are supplied domestically. Consequently, the impact per Rand spent is considerably larger for South Africa than for Botswana or Namibia. The poorer segments of the population appear to receive shares of tourism income that are smaller than their share of overall income in all three countries.
Separation and Detection of Smokeless Powder Additives by Ultra Performance Liquid Chromatography with Tandem Mass Spectrometry (UPLC/MS/MS),
Authors: Thomas Jennifer L. , Lincoln Danielle , McCord Bruce R.
Published: April 2013

A reversed phase gradient ultra performance liquid chromatography tandem mass spectrometry (UPLC/MS/MS) method has been developed for the analysis of smokeless powders. A total of 20 different components were separated byUPLCand detected byMS/MSin multiple reaction monitoring (MRM) mode. These compounds included diphenylamines, centralites, nitrotoluenes, nitroglycerin, and various phthalates. Simultaneous positive and negative electrospray ionization (ESI) was used along with negative atmospheric pressure chemical ionization (APCI) to detect all compounds in a single analysis. Analysis times were under 8 min with a gradient of 10–73% organic at a flow rate of 0.500 mL/min. With this method, ultraviolet andMRMlimits of detection ranging from 0.08 to 2.6 ng and 0.4–64 ng injected were achieved. Commercially available smokeless powders were also extracted with methylene chloride and characterized using the developedUPLC/MS/MSmethod. The procedure permits the determination of compositional differences between different brands as well as lot‐to‐lot variations.