bluuebunny/crossref_metadata_2025 huggingface dataset:
Dielectric and conductivity properties of composite polyaniline/polyurethane network
Authors: Liang C. , Gest J. , Leroy G. , Carru J.-C.
Published: September 2013

In this work, we present the dielectric characterization of polyaniline/polyurethane composite. The samples consisting of 0.5%, 1%, and 5% of polyaniline were deposited on glass fiber, and the measurements were performed in a frequency range of 20 Hz to 20 GHz. The results showed a dielectric relaxation strongly dependent on the concentration of polyaniline. This phenomenon is explained by a theoretical model. In this model, we assume that the alternative conductivity of the polymer network systems is due to conducting clusters whose lengths followed a Gaussian distribution. Depending on their size and the frequency of the excitation signal, the clusters showed a resistive or capacitive effect.
The interference effect of laser-assisted bremsstrahlung emission in Coulomb fields of two nuclei
Authors: Li Ankang , Wang Jiaxiang , Ren Na , Wang Pingxiao , Zhu Wenjun , Li Xiaoya , Hoehn Ross , Kais Sabre
Published: September 2013

In this paper, the spontaneous bremsstrahlung emission from an electron scattered by two fixed nuclei in an intense laser field is investigated in detail based upon the Volkov state and the Dirac-Volkov propagator. It has been found that the fundamental harmonic spectrum from the electron radiation exhibits distinctive fringes, which is dependent not only upon the internucleus distance and orientation but also upon the initial energy of the electron and the laser intensity. By analyzing the differential cross section, we are able to explain these effects in terms of interference among the electron scattering by the nuclei. These results could have promising applications in probing the atomic or molecular dressed potentials in intense laser fields.
Charge carrier generation, relaxation, and recombination in polytypic GaAs nanowires studied by photoluminescence excitation spectroscopy
Authors: Corfdir P. , Van Hattem B. , Uccelli E. , Fontcuberta i Morral A. , Phillips R. T.
Published: September 2013

We report results of a study of polytypic GaAs nanowires using low-temperature photoluminescence excitation spectroscopy. The nanowire ensemble shows a strong absorption at 1.517 eV, as a result of resonant generation of heavy-hole excitons in the zinc-blende segments of the nanowires. Excitons then diffuse along the length of the nanowire and are trapped by the type-II quantum discs arising from the zinc-blende/wurtzite crystal structure alternation and recombine radiatively. Finally, experiments on single nanowires demonstrate that the energy of the Γ7 conduction band to Γ9 valence band exciton of wurtzite GaAs is 1.521 eV at 4 K.
Femtosecond pulse generation in passively mode locked InAs quantum dot lasers
Authors: Finch P. , Blood P. , Smowton P. M. , Sobiesierski A. , Gwilliam R. M. , O'Driscoll I.
Published: September 2013

Optical pulse durations of an InAs two-section passively mode-locked quantum dot laser with a proton bombarded absorber section reduce from 8.4 ps at 250 K to 290 fs at 20 K, a factor of 29, with a corresponding increase in optical bandwidth. Rate equation analysis of gain and emission spectra using rate equations suggests this is due to the very low emission rate of carriers to the wetting layer in the low temperature, random population regime which enables dots across the whole inhomogeneous distribution to act as independent oscillators.
Geometrical considerations in the control and manipulation of conductive heat flux in multilayered thermal metamaterials
Authors: Vemuri Krishna P. , Bandaru Prabhakar R.
Published: September 2013

We indicate the fundamental rationale underlying the control of temperature and the manipulation of thermal flux, with reference to a multilayered composite material. We show that when the orientation of the layers in the composite is physically rotated with respect to a constant temperature gradient, there would then be a corresponding introduction of off-diagonal components in the thermal conductivity tensor and thermal anisotropy is induced. The consequent bending of the heat flux lines is found to depend on both the (i) composite rotation angle and the (ii) ratio of the thermal conductivities of the constituent materials.
Adhesion of moving droplets in microchannels
Authors: Chen Haosheng , Dong Enkai , Li Jiang , Stone Howard A.
Published: September 2013

When oil drops in a continuous water phase move from the hydrophilic to the hydrophobic section of a microchannel, they can be controlled to either adhere or not adhere on the channel by changing the capillary number. Using experiments and a model for the thin film flow, we show that the critical capillary number for adhesion is approximately Ca ∼ D3/4/d3/2, where D and d is the length of the droplet and the inner dimension of the microchannel, respectively. As one application of these ideas, droplet adhesion is demonstrated as a promising technology for recycling of emulsions in droplet microfluidics.
Growth and phase transition characteristics of pure M-phase VO2 epitaxial film prepared by oxide molecular beam epitaxy
Authors: Fan L. L. , Chen S. , Wu Y. F. , Chen F. H. , Chu W. S. , Chen X. , Zou C. W. , Wu Z. Y.
Published: September 2013

VO2 epitaxial film with large size has been prepared by oxide-molecular beam epitaxy method on Al2O3 (0001) substrate. The VO2 film shows a perfect crystal orientation, uniformity, and distinct metal-insulator phase transition (MIT) characteristics. It is observed that the MIT character is closely associated with the crystal defects such as oxygen vacancies. By controlling the growth condition, the MIT temperature can be tuned through modifying the content of oxygen vacancies. The role of the oxygen vacancies on the phase transition behavior of this VO2 film is discussed in the framework of the hybridization theory and the valence state of vanadium.
Electronic structure analysis of rare earth ions Ce and Nd doped gallium nitride
Authors: Dar Amna , Majid Abdul
Published: September 2013

First principle calculations on electronic structure of Rare Earth ions Ce and Nd doped GaN are presented. Band gap narrowing, optical transitions, and hybridization of impurity states with the host are discussed. The dopants introduced 4f states in the band gap of the doped material in such a way that REGa isoelectronic traps facilitate the optical transitions in RE:GaN. The observed formation of intermediate bands and impurity levels in band gap of host material predicted it to be excellent candidate for the future solar cell generation and other optoelectronic devices.
Transport and optical gaps and energy band alignment at organic-inorganic interfaces
Authors: Evans D. A. , Vearey-Roberts A. R. , Roberts O. R. , Williams G. T. , Cooil S. P. , Langstaff D. P. , Cabailh G. , McGovern I. T. , Goss J. P.
Published: September 2013

The transport and optical band gaps for the organic semiconductor tin (II) phthalocyanine (SnPc) and the complete energy band profiles have been determined for organic-inorganic interfaces between SnPc and III-V semiconductors. High throughput measurement of interface energetics over timescales comparable to the growth rates was enabled using in situ and real-time photoelectron spectroscopy combined with Organic Molecular Beam Deposition. Energy band alignment at SnPc interfaces with GaAs, GaP, and InP yields interface dipoles varying from −0.08 (GaP) to −0.83 eV (GaAs). Optical and transport gaps for SnPc and CuPc were determined from photoelectron spectroscopy and from optical absorption using spectroscopic ellipsometry to complete the energy band profiles. For SnPc, the difference in energy between the optical and transport gaps indicates an exciton binding energy of (0.6 ± 0.3) eV.
Asymmetric wicking and reduced evaporation time of droplets penetrating a thin double-layered porous material
Authors: Gat Amir D. , Vahdani Aria , Navaz Homayun , Nowakowski Albert , Gharib Morteza
Published: September 2013

We study numerically and experimentally the penetration and evaporation dynamics of droplets wicking into a thin double-layered porous material with order-of-magnitude difference in the physical properties between the layers. We show that such double-layered porous materials can be used to create highly asymmetrical wicking properties, preventing liquid droplets wicking from one surface to the other, while allowing wicking in the reverse direction. In addition, these double-layered porous materials are shown to reduce the evaporation time of droplets penetrating into the porous material, compared with a single-layered porous material of equal thickness and physical properties similar to either of the layers.
Sensitive trace gas detection with cavity enhanced absorption spectroscopy using a continuous wave external-cavity quantum cascade laser
Authors: van Helden J. H. , Lang N. , Macherius U. , Zimmermann H. , Röpcke J.
Published: September 2013

Trace gas sensing in the mid-infrared using quantum cascade lasers (QCLs) promises high specificity and sensitivity. We report on the performance of a simple cavity enhanced absorption spectroscopy (CEAS) sensor using a continuous wave external-cavity QCL at 7.4 μm. A noise-equivalent absorption coefficient αmin of 2.6 × 10–8 cm–1 in 625 s was achieved, which corresponds to a detection limit of 6 ± 1 ppb of CH4 in 15 millibars air for the R(3) transition at 1327.074 cm–1. This is the highest value of noise-equivalent absorption and among the longest effective path length (1780 m) reported to date with QCL-based CEAS.
Compositionally matched nitrogen-doped Ge2Sb2Te5/Ge2Sb2Te5 superlattice-like structures for phase change random access memory
Authors: Chia Tan Chun , Shi Luping , Zhao Rong , Guo Qiang , Li Yi , Yang Yi , Chong Chong Tow , Malen Jonathan A. , Ong Wee-Liat , Schlesinger Tuviah E. , Bain James A.
Published: September 2013

A compositionally matched superlattice-like (SLL) structure comprised of Ge2Sb2Te5 (GST) and nitrogen-doped GST (N-GST) was developed to achieve both low current and high endurance Phase Change Random Access Memory (PCRAM). N-GST/GST SLL PCRAM devices demonstrated ∼37% current reduction compared to single layered GST PCRAM and significantly higher write/erase endurances of ∼108 compared to ∼106 for GeTe/Sb2Te3 SLL devices. The improvements in endurance are attributed to the compositionally matched N-GST/GST material combination that lowers the diffusion gradient between the layers and the lower crystallization-induced stress in the SLL as revealed by micro-cantilever stress measurements.
A path to implement optimized randomly textured surfaces for solar cells
Authors: Wiesendanger S. , Zilk M. , Pertsch T. , Lederer F. , Rockstuhl C.
Published: September 2013

Randomly textured surfaces are nowadays routinely integrated into solar cells. Nonetheless, their performance is still not optimal. This became obvious while comparing their performance to optimized surfaces. Thus far, however, these optimized surfaces suffer from being either impossible to implement or only with expensive top-down nanofabrication technologies not suitable for large scale wafers. Here, we suggest a different approach to achieve optimized randomly textured surfaces. It exploits a self-assembled monolayer of spheres with a carefully balanced size distribution to define the random texture. Existing solar cells are outperformed with such realistic textures by up to 26%.
Improvement of polycarbazole-based organic bulk-heterojunction solar cells using 1,8-diiodooctane
Authors: Liu Zhihai , Ju Heongkyu , Lee Eun-Cheol
Published: September 2013

The use of 1,8-diiodooctane (DIO) as a solvent additive in poly[N-9′-heptadecanyl-2,7-carbazole-alt-5, 5-(4′,7′-di-2-thienyl-2′,1′,3′-benzothiadiazole)] (PCDTBT)-based bulk-heterojunction solar cells increased the power conversion efficiency (PCE) by 20.9%. This improvement was due to the increase in the fill factor and open-circuit voltage (Voc), which compensated for the decrease in the short-circuit current (Jsc). DIO had the opposite effect, increasing Jsc and decreasing Voc, in the devices using other low-band gap polymers. The best sample in this study showed a PCE of 6.27% and Voc of 939 mV, indicating that the fabricated device is an efficient solar cell with a high Voc close to 1 V.
A study on the maximum power transfer condition in an inductively coupled plasma using transformer circuit model
Authors: Kim Young-Do , Lee Hyo-Chang , Chung Chin-Wook
Published: September 2013

Correlations between the external discharge parameters (the driving frequency ω and the chamber dimension R) and plasma characteristics (the skin depth δ and the electron-neutral collision frequency νm) are studied using the transformer circuit model [R. B. Piejak et al., Plasma Sources Sci. Technol. 1, 179 (1992)] when the absorbed power is maximized in an inductively coupled plasma. From the analysis of the transformer circuit model, the maximum power transfer conditions, which depend on the external discharge parameters and the internal plasma characteristics, were obtained. It was found that a maximum power transfer occurs when δ≈0.38R for the discharge condition at which νm/ω≪1, while it occurs when δ≈2ω/νmR for the discharge condition at which νm/ω≫1. The results of this circuit analysis are consistent with the stable last inductive mode region of an inductive-to-capacitive mode transition [Lee and Chung, Phys. Plasmas 13, 063510 (2006)], which was theoretically derived from Maxwell's equations. Our results were also in agreement with the experimental results. From this work, we demonstrate that a simple circuit analysis can be applied to explain complex physical phenomena to a certain extent.
Forming free resistive switching in graphene oxide thin film for thermally stable nonvolatile memory applications
Authors: Khurana Geetika , Misra Pankaj , Katiyar Ram S.
Published: September 2013

Forming free and thermally stable bipolar resistive switching behavior was observed in the memory devices composed of graphene oxide (GO) thin films on ITO coated glass substrate with Platinum (Pt) as the top electrode. The switching between the low resistance state and high resistance state showed a reliable and repeating behavior with an on/off ratio of 104 at room temperature. The Pt/GO/ITO device showed metallic and semiconducting characteristics in low and high resistance states, respectively, when resistance was measured as a function of temperature. Ohmic conduction was found to dominate in all regions of switching operation except for the high voltage regime of high resistance state where space charge limited conduction was found to be the main mechanism of current conduction. The device showed good endurance up to 104 s and retention characteristics up to 100 cycles with on/off ratio ∼104. The switching mechanism was found to be governed by migration of oxygen between GO layer and bottom ITO electrode, which was further confirmed by Raman Spectroscopy. The device exhibited stable bipolar switching characteristics with good retention and endurance properties at high temperatures up to 500 K. The graphene oxide based memory devices fabricated by simple chemical method have potential in the field of nonvolatile memory applications well above the room temperature.
Energy resolution and related charge carrier mobility in LaBr3:Ce scintillators
Authors: Khodyuk I. V. , Quarati F. G. A. , Alekhin M. S. , Dorenbos P.
Published: September 2013

The scintillation response of LaBr3:Ce scintillation crystals was studied as function of temperature and Ce concentration with synchrotron X-rays between 9 keV and 100 keV. The results were analyzed using the theory of carrier transport in wide band gap semiconductors to gain new insights into charge carrier generation, diffusion, and capture mechanisms. Their influence on the efficiency of energy transfer and conversion from X-ray or γ-ray photon to optical photons and therefore on the energy resolution of lanthanum halide scintillators was studied. From this, we will propose that scattering of carriers by both the lattice phonons and by ionized impurities are key processes determining the temperature dependence of carrier mobility and ultimately the scintillation efficiency and energy resolution. When assuming about 100 ppm ionized impurity concentration in 0.2% Ce3+ doped LaBr3, mobilities are such that we can reproduce the observed temperature dependence of the energy resolution, and in particular, the minimum in resolution near room temperature is reproduced.
Hydrogen storage by metalized silicene and silicane
Authors: Wang Jing , Li Jingbo , Li Shu-Shen , Liu Ying
Published: September 2013

The hydrogen storage capacities of K-decorated silicene and silicane are studied using first-principles calculations. It is found that K atoms can form a uniform and stable coverage on one side of silicene and both sides of silicane. Each K atom can absorb a maximum of five H2 molecules and the hydrogen storage capacity of K-decorated silicane can reach 6.13 wt. % with an average adsorption energy of 0.133 eV/H2. This hydrogen storage capacity is in excess of 6 wt. %, the U. S. Department of Energy target. This is a remarkable result indicating another application of silicene/silicane as a potential high-capacity storage medium.
Effect of oxygen defects on ferromagnetism of Mn doped ZnO
Authors: Liu Weijing , Tang Xiaodong , Tang Zheng
Published: September 2013

Mn doped ZnO nano-particles were synthesized by a solution route and annealed in N2, O2, and Ar, respectively. X-ray diffraction and X-ray photoelectron spectroscopy measurements show that the samples possess typical wurtzite structure and have no other impurity phases. Magnetization loops for ZnO samples were measured and clearly show typical ferromagnetic saturation behavior. With the combination of defect analysis based on photoluminescence spectroscopy and first-principle calculations of the possible magnetic defect centers in Mn doped ZnO, the effect of defects on the nature and origin of ferromagnetism was investigated. The results suggest oxygen vacancies, especially singly ionized oxygen vacancies, play a crucial role in mediating ferromagnetism in the Mn doped ZnO system.
Effects of Er doping site and concentration on piezoelectric, ferroelectric, and optical properties of ferroelectric Na0.5Bi0.5TiO3
Authors: Luo Laihui , Du Peng , Li Weiping , Tao Weidong , Chen Hongbing
Published: September 2013

The piezoelectric, ferroelectric, and optical properties of Er-doped Na0.5Bi0.5TiO3 ceramics were investigated in terms of Er3+ ion occupying the A- and B-site with different Er ion concentrations. Compared with B-site doped samples, the A-site doped ceramics have much stronger piezoelectricity, ferroelectric property, and luminescence intensity. Upon the excitation of 980 nm, all the Er-doped Na0.5Bi0.5TiO3 ceramics exhibit strong green and red emissions. The present investigation demonstrates that the relative intensity of green and red upconversion emissions can be tuned by changing Er ion concentration. In this study, influence of the electrical and luminescence properties of the Er doped ceramics is discussed.
English and lexical inventiveness in the Italian linguistic landscape
Authors: Vettorel Paola , Franceschi Valeria
Published: September 2013

The study of the linguistic landscape has seen a growing interest in recent years, focusing on written information publicly available in a given territory, city or area (Landry & Bourhis 1997). English is widely present in the linguistic landscape worldwide (e.g. Cenoz & Gorter 2006, 2008; Shohamy & Gorter 2009; Shohamy et al. 2010), often in its lingua franca role (Bruyèl-Olmedo & Juan-Garau 2009), and Italy appears to be no exception (Ross 1997; Schlick 2003; Griffin 2004; Gorter 2007; Coluzzi 2009).This paper investigates examples of lexical inventiveness involving English in a set of data gathered in the linguistic landscape of some cities and towns in Veneto (Northern Italy), each with different though complementary contextual characteristics. Signs containing English, either monolingually or in combination with Italian, were selected and analysed as to lexical creativity, as well as semantic shifts/extensions. The data shows that English is often employed both in monolingual and in hybrid/bilingual processes at several linguistic levels, from orthography to word-formation (Huebner 2006), testifying to its pervasive presence in expanding circle contexts, either as a (globalized) symbol of modernity or in appropriating linguistic practices. Keywords: English in the linguistic landscape; lexical inventiveness; word-formation; English and local languages; English as a Lingua Franca
Filling the gaps
Authors: Renouf Antoinette , Kehoe Andrew
Published: September 2013

The aim of this paper is to demonstrate the functionality of the WebCorp Linguist’s Search Engine (WebCorpLSE) by comparing it with two other freely-available online data resources: Google and the Corpus of Contemporary American English (COCA). In particular, the paper looks at how WebCorpLSE can fill gaps in these sources. It begins by contextualising the WebCorpLSE project in relation to its parent project, WebCorp, and other ‘web as corpus’ initiatives. It then outlines the advantages of WebCorpLSE over Google search, before turning to a comparison of WebCorpLSE with COCA. Comparisons are made by matching extracts of textual and graphical output generated by each system. It is shown that WebCorpLSE provides information not available via the other search mechanisms, and that it can thus, in accordance with Mair’s (2007) argument for a combined approach to diachronic text study, usefully serve not only as a stand-alone tool, but as a complementary resource.
Representing own and other voices in social science research articles
Authors: Parkinson Jean
Published: September 2013

That complement clauses are a prominent feature of various registers including conversation and academic prose. In academic prose, that-clauses are of interest because they frame research findings, the writer’s central message to the reader. To achieve this persuasive purpose, that-clauses are employed to draw in various voices, including those of other researchers, research participants, research findings and the writer. This study extends prior investigation of complement clauses to examine their distribution across different sections of a corpus of research articles in social science. The social action of each section is partially achieved through what the different voices in the different sections of the article talk about, and the subtle variations in the stance of the author and other voices across sections. This study finds that use of reporting verbs is nuanced according to authors’ purposes in different sections, and also according to the source of the proposition in the that-clause.
Lexical bundles across four legal genres
Authors: Breeze Ruth
Published: September 2013

Legal language is often said to be formulaic, but little research is available on the nature of frequently occurring sequences of words in different legal genres. This article investigates the lexical bundles found in four legal corpora: academic law, case law, legislation, and documents. Major differences are brought to light between the type of bundles that are found, and the roles they have in the text. Academic legal writing uses relatively little formulaic language. Case law uses noun phrase bundles relating to agents, documents and actions, as well as many extended prepositional phrases. Legislation and documents contain many noun phrase bundles, and verb phrase bundles with a deontic or referential function. The function of these different types of bundle as parts of a schematic frame or as slot-fillers is discussed.
Interfacing corpus linguistics and computational stylistics
Authors: Grabowski Lukasz
Published: September 2013

This study attempts to examine the potential of selected corpus linguistics and computational stylistics methods in the investigation of translation universals in translational literary Polish. It deals with T-universals (Chesterman 2004), with emphasis on the simplification hypothesis, as manifested in the core patterns of lexical use (Laviosa 1998) and the levelling out hypothesis (Baker 1996). To that end, the purpose-designed corpora, each with approximately 350,000 tokens, of contemporary translational and non-translational literary Polish were compiled. The results confirm the simplification and the levelling out hypotheses but only with reference to the mean sentence length and variance for the mean sentence length. On the other hand, the results of multivariate analyses (Principal Components Analysis and Cluster Analysis) confirm the levelling out hypothesis that translations are more alike as compared with native texts.
Managing ideological differences in joint political press conferences
Authors: Moberg Ulla , Eriksson Göran
Published: September 2013

This study focuses on Swedish political press conferences and explores the discursive efforts of politicians to express unity despite diverging ideological views. It concerns the use of the first person pronoun ‘we’ (Swedish.we) and is influenced by both dialogue theory and linguistic theories, which highlight the meaning of pronouns in context. The data consist of transcribed web broadcasts of press conferences with the leaders of the four political parties that form the Swedish Government since 2006. Our analysis reveals that a clear-cut use of the personal pronoun ‘we’ can serve the same political purposes as a more ambiguous use, i.e. to show unity while there are differences. The four party leaders are involved in a communicative project of ‘doing unity’ to demonstrate that they are a very capable government.
Pragmatics meets ideology
Authors: Ivković Dejan
Published: September 2013

Serbian is a unique example of active digraphia, that is, the use of two scripts by the same speech community. Writers of Serbian use both the Cyrillic and Latin alphabets in various domains. Moreover, the Internet has brought to the fore competing orthographic variants within the Serbian Latin writing system. Technology-driven and ideologically motivated, non-standardde factoorthographic norms emerge as a result of the medium’s affordances embedded in a given socio-political context. This paper presents a case study on alphabet choice and the use of non-standard orthographic variants on two Serbian news websites,Politika OnlineandB92. The results show that a two-fold process occurs in Serbian orthographic practices, emerging from Internet discourses from below, including online commentaries: the dominance of the Latin alphabet over Cyrillic; and the stabilization of non-standard Latin orthographic variants. Metalinguistic commentaries of online posters illustrate the tension between pragmatic concerns and language ideologies.
What’s in a word? Your enemy combatant is my refugee
Authors: Beaton-Thome Morven
Published: September 2013

As a result of the fierce controversy surrounding Guantánamo Bay detention camp, the process of naming, or lexicalising, the group of individuals detained there has become central in legitimising or challenging their detention. This positioning becomes even more complex when conducted in a multilingual setting where such lexical choices are also simultaneously interpreted. In this paper, a case study of a simultaneously interpreted plenary debate from the European Parliament (EP) on the potential resettlement of Guantánamo detainees in European Union (EU) member states is presented, with particular focus on the impact of simultaneous interpreting on the negotiation of contested lexical labels. After conceptualising plenary debate at the EP as multivoiced discourse (Bakhtin 1981), this paper investigates the rhetorical strategies employed in the process of overlexicalising Guantánamo detainees throughout the German and English original and interpreted versions of the debate. Interpreter response to controversial lexical labels is then explored, before instances of interpreter intervention in the form of lexical contraction and self-correction are analysed in relation to the ideological impact of such intervention on the multiple voices present in the debate.
How the approval system affects Chinese scientific journals
Authors: LIN Songqing
Published: September 2013

Chinese scientific journals are moving in the right direction but developing first‐class academic journals still requires a number of obstacles to be overcome. Before the birth of any journal, a very complex journal approval system (JAS) must be negotiated. The paper will first present the history of the JAS in China and then analyze its effect on the scientific journal system. The JAS poses potential risks to the development of journals, and journal quantity rather than quality is the current priority. This needs to be changed and the JAS should be replaced by a journal registration system. Simultaneously, a system in which entry (start up) and closure, if required, is much easier than at present should be introduced, allowing the market to be the principal arbiter of success or failure.
Book review
Authors: CLARK Cindy
Published: September 2013

Copyright Questions and Answers for Information Professionals: From the Columns of Against the Grain Laura N. Gasaway West Lafayette, Indiana, Purdue University Press, 2013, 284pp. ISBN: 978‐1‐55753‐639‐6, £16.12, pbk
The new engagement game: the role of gamification in scholarly publishing
Authors: ARMSTRONG David
Published: September 2013

Gamification – the application of game mechanics to solve problems and engage users – is gathering significant momentum in the wider business world, and there are many ways in which it could benefit librarians, academic publishers, and learned societies. At its core, gamification is a way of tapping into motivational forces to increase individual investment in a system, process, or resource; applied correctly, these mechanics could be used to increase engagement with a publisher's back catalogue, drive society members to explore the value their membership offers, and encourage students to connect with on‐campus learning resources. Gamification can help satisfy both business and audience objectives, but frameworks have to be carefully designed to avoid some of the common pitfalls that such systems face. Although there are few examples of gamification at work in the learned publishing sector, those who are willing to explore, experiment, and iterate on solutions will be better placed to meet the needs of the increasing ‘digital native’ student and academic population.
How to spot Ugly Black Ducklings: the next competitive frontiers in scholarly publishing
Authors: FROEHLICH Peter
Published: September 2013

This paper reviews events of SSP 2013 and AAUP 2013 within the context of Nassim Nicholas Taleb's notions of Black Swans (unexpected game changers) to anticipate the formation of competitive arenas (i.e. new models and revenue streams) for scholarly communications. It examines Tim O'Reilly's keynote address at SSP 2013, the advice of Michael Schrage from the opening Plenary at AAUP 2013, and Tim Sullivan's discussion of Harvard Business Publication's use of a topical blog network as new publishing platform to access global digital communications networks. The essay extrapolates from the case studies presented to overlay the strategies of successful practitioner presses and the advice of sought‐after business consultants on the work of academic houses, to imagine the next competitive frontier(s) in scholarly publishing.
RUBRIQ: tools, services, and software to improve peer review
Authors: STEMMLE Laura , COLLIER Keith
Published: September 2013

Rubriq is on a mission to put lost time back into research. We estimate that 15 million hours are lost each year to redundant peer review as papers get rejected and flow down the journal prestige pyramid. Rubriq uses an author‐pays model to facilitate fast, independent, and standardized peer review performed by three academic peers who are financially compensated for their efforts. Authors receive the reviews as well as a detailed journal recommendation report in 1–2 weeks. This service is designed to improve journal selection, supplement editorial reviews, and make peer review more portable between journals. The creation of the standardized scorecard is just the first phase of Rubriq's plans to improve the scholarly communication workflow. Through lessons learned over the past year, the Rubriq approach is evolving into a broader set of tools, software, and services designed to speed and improve the scholarly communication process.
Molecular causes of transcriptional response: a Bayesian prior knowledge approach
Authors: Zarringhalam Kourosh , Enayetallah Ahmed , Gutteridge Alex , Sidders Ben , Ziemek Daniel
Published: September 2013

Motivation: The abundance of many transcripts changes significantly in response to a variety of molecular and environmental perturbations. A key question in this setting is as follows: what intermediate molecular perturbations gave rise to the observed transcriptional changes? Regulatory programs are not exclusively governed by transcriptional changes but also by protein abundance and post-translational modifications making direct causal inference from data difficult. However, biomedical research over the last decades has uncovered a plethora of causal signaling cascades that can be used to identify good candidates explaining a specific set of transcriptional changes.

Methods: We take a Bayesian approach to integrate gene expression profiling with a causal graph of molecular interactions constructed from prior biological knowledge. In addition, we define the biological context of a specific interaction by the corresponding Medical Subject Headings terms. The Bayesian network can be queried to suggest upstream regulators that can be causally linked to the altered expression profile.

Results: Our approach will treat candidate regulators in the right biological context preferentially, enables hierarchical exploration of resulting hypotheses and takes the complete network of causal relationships into account to arrive at the best set of upstream regulators. We demonstrate the power of our method on distinct biological datasets, namely response to dexamethasone treatment, stem cell differentiation and a neuropathic pain model. In all cases relevant biological insights could be validated.

Availability and implementation: Source code for the method is available upon request.

Contact:  daniel.ziemek@pfizer.com

Supplementary information:  Supplementary data are available at Bioinformatics online.
Hominoid fission of chromosome 14/15 and the role of segmental duplications
Authors: Giannuzzi Giuliana , Pazienza Michele , Huddleston John , Antonacci Francesca , Malig Maika , Vives Laura , Eichler Evan E. , Ventura Mario
Published: September 2013

Ape chromosomes homologous to human chromosomes 14 and 15 were generated by a fission event of an ancestral submetacentric chromosome, where the two chromosomes were joined head-to-tail. The hominoid ancestral chromosome most closely resembles the macaque chromosome 7. In this work, we provide insights into the evolution of human chromosomes 14 and 15, performing a comparative study between macaque boundary region 14/15 and the orthologous human regions. We construct a 1.6-Mb contig of macaque BAC clones in the region orthologous to the ancestral hominoid fission site and use it to define the structural changes that occurred on human 14q pericentromeric and 15q subtelomeric regions. We characterize the novel euchromatin–heterochromatin transition region (∼20 Mb) acquired during the neocentromere establishment on chromosome 14, and find it was mainly derived through pericentromeric duplications from ancestral hominoid chromosomes homologous to human 2q14–qter and 10. Further, we show a relationship between evolutionary hotspots and low-copy repeat loci for chromosome 15, revealing a possible role of segmental duplications not only in mediating but also in “stitching” together rearrangement breakpoints.
In Planta Assessment of the Role of ThioredoxinhProteins in the Regulation ofS-Locus Receptor Kinase Signaling in Transgenic Arabidopsis
Authors: Yamamoto Masaya , Nasrallah June B.
Published: September 2013

The self-incompatibility (SI) response of the Brassicaceae is mediated by allele-specific interaction between the stigma-localized S-locus receptor kinase (SRK) and its ligand, the pollen coat-localized S-locus cysteine-rich protein (SCR). Based on work in Brassica spp., the thioredoxin h-like proteins THL1 and THL2, which interact with SRK, have been proposed to function as oxidoreductases that negatively regulate SRK catalytic activity. By preventing the spontaneous activation of SRK in the absence of SCR ligand, these thioredoxins are thought to be essential for the success of cross pollinations in self-incompatible plants. However, the in planta role of thioredoxins in the regulation of SI signaling has not been conclusively demonstrated. Here, we addressed this issue using Arabidopsis thaliana plants transformed with the SRKb-SCRb gene pair isolated from self-incompatible Arabidopsis lyrata. These plants express an intense SI response, allowing us to exploit the extensive tools and resources available in A. thaliana for analysis of SI signaling. To test the hypothesis that SRK is redox regulated by thioredoxin h, we expressed a mutant form of SRKb lacking a transmembrane-localized cysteine residue thought to be essential for the SRK-thioredoxin h interaction. We also analyzed transfer DNA insertion mutants in the A. thaliana orthologs of THL1 and THL2. In neither case did we observe an effect on the pollination responses of SRKb-expressing stigmas toward incompatible or compatible pollen. Our results are consistent with the conclusion that, contrary to their proposed role, thioredoxin h proteins are not required to prevent the spontaneous activation of SRK in the A. thaliana stigma.
Purinergic signalling: from discovery to current developments
Authors: Burnstock Geoffrey
Published: September 2013

New Findings

What is the topic of this review?

This is a personal historical review about the discovery and the main conceptual advances leading to our current understanding of purinergic signalling. The contributions of leading figures in the field are acknowledged. It includes the discovery of purinergic neuromuscular and synaptic transmission, cotransmission, the identification of P1 (adenosine), P2X nucleotide ion channel and P2Y nucleotide G protein‐coupled receptors, the identity of ectonucleotidases and release of ATP from cells by mechanical stimulation and mechanosensory transduction.

What advances does it highlight?

It highlights the pathophysiology of purinergic signalling and recent therapeutic developments.

This lecture is about the history of the purinergic signalling concept. It begins with reference to the paper by Paton & Vane published in 1963, which identified non‐cholinergic relaxation in response to vagal nerve stimulation in several species, although they suggested that it might be due to sympathetic adrenergic nerves in the vagal nerve trunk. Using the sucrose gap technique for simultaneous mechanical and electrical recordings in smooth muscle (developed while in Feldberg's department in the National Institute for Medical Research) of the guinea‐pig taenia coli preparation (learned when working in Edith Bülbring's smooth muscle laboratory in Oxford Pharmacology), we showed that the hyperpolarizations recorded in the presence of antagonists to the classical autonomic neurotransmitters, acetylcholine and noradrenaline, were inhibitory junction potentials in response to non‐adrenergic, non‐cholinergic neurotransmission, mediated by intrinsic enteric nerves controlled by vagal and sacral parasympathetic nerves. We then showed that ATP satisfied the criteria needed to identify a neurotransmitter released by these nerves. Subsequently, it was shown that ATP is a cotransmitter in all nerves in the peripheral and central nervous systems. The receptors for purines and pyrimidines were cloned and characterized in the early 1990s, and immunostaining showed that most non‐neuronal cells as well as nerve cells expressed these receptors. The physiology and pathophysiology of purinergic signalling is discussed.
Postexercise syncope: Wingate syncope test and effective countermeasure
Authors: Lacewell Alisha N. , Buck Tahisha M. , Romero Steven A. , Halliwill John R.
Published: September 2013

New Findings

What is the central question of this study?

Does a modified version of the Wingate anaerobic power test produce presyncopal signs and symptoms in healthy individuals? Does an inspiratory threshold device work as a countermeasure against postexercise syncope?

What is the main finding and its importance?

A modified Wingate test is a good model to induce postexercise syncope, and syncopal symptoms can be ameliorated by an inspiratory threshold device.

Altered systemic haemodynamics following exercise can compromise cerebral perfusion and result in syncope. As the Wingate anaerobic test often induces presyncope, we hypothesized that a modified Wingate test could form the basis of a novel model for the study of postexercise syncope and a test bed for potential countermeasures. Along these lines, breathing through an impedance threshold device has been shown to increase tolerance to hypovolaemia, and could prove beneficial in the setting of postexercise syncope. Therefore, we hypothesized that a modified Wingate test followed by head‐up tilt would produce postexercise syncope, and that breathing through an impedance threshold device (countermeasure) would prevent postexercise syncope in healthy individuals. Nineteen recreationally active men and women underwent a 60 deg head‐up tilt during recovery from the Wingate test while arterial pressure, heart rate, end‐tidal CO2 and cerebral tissue oxygenation were measured on a control day and a countermeasure day. The duration of tolerable tilt was increased by a median time of 3 min 48 s with countermeasure in comparison to the control (P < 0.05), and completion of the tilt test increased from 42 to 67% with the countermeasure. During the tilt, mean arterial pressure was greater (108.0 ± 4.1 versus 100.4 ± 2.4 mmHg; P < 0.05) with the countermeasure in comparison to the control. These data suggest that the Wingate syncope test produces a high incidence of presyncope, which is sensitive to countermeasures such as inspiratory impedance.
Occurrence of Potentially Human-Pathogenic Escherichia coli O103 in Norwegian Sheep
Authors: Sekse Camilla , Sunde Marianne , Hopp Petter , Bruheim Torkjel , Cudjoe Kofitsyo Sewornu , Kvitle Bjørg , Urdahl Anne Margrete
Published: September 2013

The investigation of an outbreak of hemorrhagic-uremic syndrome in Norway in 2006 indicated that the outbreak strain
Escherichia coli
O103:H25 could originate from sheep. A national survey of the Norwegian sheep population was performed, with the aim of identifying and describing a possible reservoir of potentially human-pathogenic
E. coli
O103, in particular of the H types 2 and 25. The investigation of fecal samples from 585 sheep flocks resulted in 1,222
E. coli
O103 isolates that were analyzed for the presence of
eae
and
stx
genes, while a subset of 369 isolates was further examined for flagellar antigens (H typing),
stx
subtypes,
bfpA
,
astA
, and molecular typing by pulsed-field gel electrophoresis (PFGE). The total ovine
E. coli
O103 serogroup was genetically diverse by numbers of H types, virulotypes, and PFGE banding patterns identified, although a tendency of clustering toward serotypes was seen. The flocks positive for potentially human-pathogenic
E. coli
O103 were geographically widely distributed, and no association could be found with county or geographical region. The survey showed that
eae
-negative,
stx
-negative
E. coli
O103, probably nonpathogenic to humans, is very common in sheep, with 27.5% of flocks positive. Moreover, the study documented a low prevalence (0.7%) of potentially human-pathogenic Shiga toxin-producing
E. coli
O103:H2, while STEC O103:H25 was not detected. However, 3.1% and 5.8% of the flocks were positive for enteropathogenic
E. coli
O103 belonging to H types 2 and 25, respectively. These isolates are of concern as potential human pathogens by themselves but more importantly as possible precursors for human-pathogenic STEC.
Rapid Transposon Liquid Enrichment Sequencing (TnLE-seq) for Gene Fitness Evaluation in Underdeveloped Bacterial Systems
Authors: Fels Samuel R. , Zane Grant M. , Blake Sean M. , Wall Judy D.
Published: September 2013

Whole-genome fitness analysis in microbes that uses saturating transposon mutagenesis combined with massively parallel sequencing (Tn-seq) is providing a measure of the contribution of each gene to a given growth condition. With this technique, gene fitness profiles and essential genes are discovered by simultaneous analyses of whether the absence of each gene product alters the growth kinetics of the bacterium. Here we modify the standard Tn-seq procedure to simplify and shorten the process by including delivery of the transposon through conjugation and liquid culture enrichment of the mutant pool, creating transposon liquid enrichment sequencing (TnLE-seq). To illustrate the success of these modifications and the robustness of the procedure, analyses of gene fitness of two cultures of the strictly anaerobic bacterium
Desulfovibrio vulgaris
Hildenborough were performed, with growth on lactate as the electron donor and sulfate as the electron acceptor. These data demonstrate reproducibility and provide a base condition for analysis of fitness changes in deletion mutants and in various growth conditions. The procedural modifications will facilitate the application of this powerful genetic analysis to microbes lacking a facile genetic system. Pilot studies produced 2.5 × 10
5
and 3.4 × 10
5
unique insertion mutants in the anaerobe
Desulfovibrio vulgaris
Hildenborough grown under typical laboratory conditions in rich medium. These analyses provided two similar high-resolution maps of gene fitness across the genome, and the method was also applied to growth in minimal medium. These results were also compared to the coverage obtained with a ca. 13,000-member cataloged transposon library constructed by sequencing transposon insertion sites in individual mutants.
High-Efficiency Thermal Asymmetric Interlaced PCR (hiTAIL-PCR) for Determination of a Highly Degenerated Prophage WO Genome in a Wolbachia Strain Infecting a Fig Wasp Species
Authors: Wang Guan-Hong , Xiao Jin-Hua , Xiong Tuan-Lin , Li Zi , Murphy Robert W. , Huang Da-Wei
Published: September 2013

Temperate bacteriophage WO is a model system for studying tripartite interactions among viruses, bacteria, and eukaryotes, especially investigations of the genomic stability of obligate intracellular bacteria. Few WO genomes exist because of the difficulty in isolating viral DNA from eukaryotic hosts, and most reports are by-products of
Wolbachia
sequencing. Only one partial genome of a WO phage has been determined directly from isolated particles. We determine the complete genome sequence of prophage WO (WOSol) in
Wolbachia
strain
w
Sol, which infects the fig wasp
Ceratosolen solmsi
(Hymenoptera: Chalcidoidea), by high-efficiency thermal asymmetric interlaced PCR. The genome of WOSol is highly degenerated and disrupted by a large region (14,267 bp) from
Wolbachia
. Consistent with previous molecular studies of multiple WO genomes, the genome of WOSol appears to have evolved by single nucleotide mutations and recombinations.