bluuebunny/crossref_metadata_2025 huggingface dataset:
Free Poisson Hopf algebras generated by coalgebras
Authors: Agore A. L.
Published: July 2014

We construct the analogue of Takeuchi's free Hopf algebra in the setting of Poisson Hopf algebras. More precisely, we prove that there exists a free Poisson Hopf algebra on any coalgebra or, equivalently that the forgetful functor from the category of Poisson Hopf algebras to the category of coalgebras has a left adjoint. In particular, we also prove that the category of Poisson Hopf algebras is a reflective subcategory of the category of Poisson bialgebras. Along the way, we describe coproducts and coequalizers in the category of Poisson Hopf algebras, therefore showing that the latter category is cocomplete.
Plastic behavior of aluminum in high strain rate regime
Authors: Shu Hua , Fu Sizu , Huang Xiuguang , Pan Hao , Zhang Fan , Xie Ziyong , Ye Junjian , Jia Guo
Published: July 2014

The aim of this experiment was to study the plastic response of Al to dynamic loading at high strain rates. Dynamic loading was applied by direct laser ablation of the sample with pulse width of 3 ns long. The free surface velocity histories of shock loaded samples, 60-310 μm thick at room temperature, and 150 μm thick with initial temperature from 293 to 893 K, have been recorded using a line velocity interferometer for any reflections (VISAR) system. The line VISAR could measure free surface velocity profile with high temporal resolution (∼100 ps). The measured amplitudes of the elastic precursor waves have been approximated by power functions of the propagation distance with the power index of 0.581, and these data have been converted into relationships between the shear stress at Hugoniot elastic limit and the initial plastic strain rate. The peak longitudinal elastic stress and the strain rate meet a power law dependency with the power index of 0.44. Samples were recovered for post-shot metallographic analysis. The metallographic analysis leads to the conclusion that the spall strength of preheated aluminum is determined more by the rate of void nucleation rather than its growth.
Simultaneous imaging of the ferromagnetic and ferroelectric structure in multiferroic heterostructures
Authors: Unguris J. , Bowden S. R. , Pierce D. T. , Trassin M. , Ramesh R. , Cheong S.-W. , Fackler S. , Takeuchi I.
Published: July 2014

By measuring the spin polarization of secondary electrons and the intensity of backscattered electrons generated in a scanning electron microscope, we are able to simultaneously image the ferromagnetic domain structure of a ferromagnetic thin film and the ferroelectric domain structure of the underlying ferroelectric substrate upon which it is grown. Simultaneous imaging allows straightforward, quantitative measurements of the correlations in these complex multiferroic systems. We have successfully imaged domains in CoFe/BFO and Fe/BTO, two systems with very different ferromagnet/ferroelectric coupling mechanisms, demonstrating how this technique provides a new local probe of magneto electric/strictive effects in multiferroic heterostructures.
Thermoelectric properties of indium doped PbTe1-ySey alloys
Authors: Bali Ashoka , Wang Heng , Snyder G. Jeffrey , Mallik Ramesh Chandra
Published: July 2014

Lead telluride and its alloys are well known for their thermoelectric applications. Here, a systematic study of PbTe1-ySey alloys doped with indium has been done. The powder X-Ray diffraction combined with Rietveld analysis confirmed the polycrystalline single phase nature of the samples, while microstructural analysis with scanning electron microscope results showed densification of samples and presence of micrometer sized particles. The temperature dependent transport properties showed that in these alloys, indium neither pinned the Fermi level as it does in PbTe, nor acted as a resonant dopant as in SnTe. At high temperatures, bipolar effect was observed which restricted the zT to 0.66 at 800 K for the sample with 30% Se content.
Effect of chaos on plasma filament dynamics and turbulence in the scrape-off layer
Authors: Meyerson D. , Michoski C. , Waelbroeck F. , Horton W.
Published: July 2014

Naturally occurring error fields as well as resonant magnetic perturbations applied for stability control are known to cause magnetic field-line chaos in the scrape-off layer (SOL) region of tokamaks. Here, 2D simulations with the BOUT++ simulation framework are used to investigate the effect of the field-line chaos on the SOL and in particular on its width and peak particle flux. The chaos enters the SOL dynamics only through the connection length, which is evaluated using a Poincaré map. The variation of experimentally relevant quantities, such as the SOL gradient length scale and the intermittency of the particle flux in the SOL, is described as a function of the strength of the magnetic perturbation. It is found that the effect of the chaos is to broaden the profile of the sheath-loss coefficient, which is proportional to the inverse connection length. That is, the SOL transport in a chaotic field is equivalent to that in a model where the sheath-loss coefficient is replaced by its average over the unperturbed flux surfaces. The model does not include the effects of chaotic features other than the parallel connection length.
Role of stochasticity in turbulence and convective intermittent transport at the scrape off layer of Ohmic plasma in QUEST
Authors: Banerjee Santanu , Zushi H. , Nishino N. , Hanada K. , Ishiguro M. , Tashima S. , Liu H. Q. , Mishra K. , Nakamura K. , Idei H. , Hasegawa M. , Fujisawa A. , Nagashima Y. , Matsuoka K.
Published: July 2014

Statistical features of fluctuations are investigated using the fast camera imaging technique in the scrape of layer (SOL) of electron cyclotron resonance heated Ohmic plasma. Fluctuations in the SOL towards low field side are dominated by coherent convective structures (blobs). Two dimensional structures of the higher order moments (skewness s and kurtosis k) representing the shape of probability density function (PDF) are studied. s and k are seen to be functions of the magnetic field lines. s and k are consistently higher towards the bottom half of the vessel in the SOL showing the blob trajectory along the field lines from the top towards bottom of the vessel. Parabolic relation (k=As2+C) is observed between s and k near the plasma boundary, featuring steep density gradient region and at the far SOL. The coefficient A, obtained experimentally, indicates a shift of prominence from pure drift-wave instabilities towards fully developed turbulence. Numerical coefficients characterizing the Pearson system are derived which demonstrates the progressive deviation of the PDF from Gaussian towards gamma from the density gradient region, towards the far SOL. Based on a simple stochastic differential equation, a direct correspondence between the multiplicative noise amplitude, increased intermittency, and hence change in PDF is discussed.
Strong correlated pinning at high growth rates in YBa2Cu3O7−x thin films with Ba2YNbO6 additions
Authors: Ercolano G. , Bianchetti M. , Sahonta S.-L. , Kursumovic A. , Lee J. H. , Wang H. , MacManus-Driscoll J. L.
Published: July 2014

In pulsed laser deposited YBa2Cu3O7−x thin films containing 5 mol. % Ba2YNbO6 pinning additions, we show that a growth rate of 1 nm/s (10 Hz laser repetition rate with an instant rate ∼0.1 nm/pulse) gives remarkably strong c-axis correlated pinning which is associated with the presence of Ba2YNbO6 nanocolumns. This is different to the behaviour of other well-studied pinning additions where only random nanoparticles of the pinning phase are present at high growth rates and is an important finding for industrial fabrication of coated conductors where fast growth is required.
Role of magnetic anisotropy on the magnetic properties of Ni nanoclusters embedded in a ZnO matrix
Authors: Nunes W. C. , Borges R. P. , Cruz M. M. , da Silva R. C. , Wahl U. , Cuchillo A. , Vargas P. , Magen C. , Godinho M.
Published: July 2014

We have investigated the magnetic properties of Ni nanoaggregates produced by ion implantation in ZnO single crystals. Several deviations from classical models usually adopted to describe the magnetic properties of nanoparticle systems were found. The strain between host and Ni nanoaggregates induces a magnetic anisotropy with a preferred direction. We show that these anisotropy effects can be misinterpreted as a ferromagnetic or antiferromagnetic coupling among the nanoaggregates similar to that of an oriented, interacting nanocrystal ensemble.
Superspin glassy behaviour of La0.7Ca0.3Mn0.85Al0.15O3 thin film
Authors: Kumar Manish , Choudhary R. J. , Shukla D. K. , Phase D. M.
Published: July 2014

Here, we present the low temperature magnetic behaviour of epitaxial La0.7Ca0.3Mn0.85Al0.15O3 (LCMAO) thin film through a series of DC magnetic measurements. Overall behaviour inferred from the magnetization measurements indicate that the magnetic phases created due to Al doping induced inhomogeneous distribution of Mn3+ and Mn4+ ions and oxygen vacancies present in the system act like superspins, and the strong interaction among themselves results in the superspin glassy behaviour. Interactions among the superspins are marked by the aging and zero filed memory effects. The glassy magnetic phase in LCMAO is found to follow the hierarchical model of spin glasses.
Size effects in twinned nanopillars
Authors: Hammami Farah , Kulkarni Yashashree
Published: July 2014

Nanotwinned structures are becoming increasingly attractive owing to their potential as optimal motifs for strength, ductility, and grain stability in metals. In this work, we use nanopillar compression as a paradigmatic problem to investigate the interplay between size effects associated with the twin spacing and the finite size of the nanopillars by way of molecular dynamics simulations. Our simulations reveal that the aspect ratio plays an important role in governing the weakening or strengthening effect of coherent twin boundaries under uniaxial compression. We find that there exists an optimal aspect ratio for which the yield strength of twinned nanopillars is slightly higher than even single crystal nanopillars. In addition, we observe that twin boundaries facilitate dislocation-starvation as defects glide along twin boundaries and are eliminated at the free surface.
Can spurious indications for phase synchronization due to superimposed signals be avoided?
Authors: Porz Stephan , Kiel Matthäus , Lehnertz Klaus
Published: July 2014

We investigate the relative merit of phase-based methods—mean phase coherence, unweighted and weighted phase lag index—for estimating the strength of interactions between dynamical systems from empirical time series which are affected by common sources and noise. By numerically analyzing the interaction dynamics of coupled model systems, we compare these methods to each other with respect to their ability to distinguish between different levels of coupling for various simulated experimental situations. We complement our numerical studies by investigating consistency and temporal variations of the strength of interactions within and between brain regions using intracranial electroencephalographic recordings from an epilepsy patient. Our findings indicate that the unweighted and weighted phase lag index are less prone to the influence of common sources but that this advantage may lead to constrictions limiting the applicability of these methods.
Investigation of the Mn3−δGa/MgO interface for magnetic tunneling junctions
Authors: ViolBarbosa C. E. , Ouardi S. , Kubota T. , Mizukami S. , Fecher G. H. , Miyazaki T. , Kozina X. , Ikenaga E. , Felser C.
Published: July 2014

The Mn3Ga Heusler compound and related alloys are the most promising materials for the realization of spin-transfer-torque magnetoresistive memories. Mn–Ga films exhibits perpendicular magnetic anisotropy and high spin polarization and can be used to improve the performance of MgO-based magneto tunneling junctions. The interface between Mn–Ga and MgO films were chemically characterized by hard x-ray photoelectron spectroscopy. The experiment indicated the formation of Ga-O bonds at the interface and evidenced changes in the local environment of Mn atoms in the proximity of the MgO film. We show that the deposition of few monoatomic layers of Mg on top of Mn–Ga film, before the MgO deposition, strongly suppresses the oxidation of gallium.
Effects of phase separation on the thermoelectric properties of (Ti, Zr, Hf)NiSn half-Heusler alloys
Authors: Geng Huiyuan , Zhang Hao
Published: July 2014

Ti substitution is a common strategy to further reduce the lattice thermal conductivity of (Zr,Hf)NiSn half-Heusler thermoelectric alloys, but phase separations are also observed in the resulting substituted samples. The n-type (Tix(Zr0.5Hf0.5)1−x)0.99Ta0.01NiSn alloys (x = 0.34, 0.4, 0.5, and 0.6), which are produced by arc-melting followed by annealing, show a phase separation into a Ti-poor primary dendritic half-Heusler phase and a Ti-rich interdendritic half-Heusler phase. For example, the x = 0.4 alloy consists of two phases: (Ti0.36Zr0.32Hf0.32)0.99Ta0.01NiSn and (Ti0.44Zr0.28Hf0.28)0.99Ta0.01NiSn. Using a detailed study of the phonon-scattering parameters of the single phase (Ti, Zr, Hf)NiSn compound as a function of mass and strain field fluctuations, a quantitative model of the lattice thermal conductivity has been successfully established. Based on this, the effective lattice thermal conductivity of the phase-separated samples can be well explained by the classical theory of composited medium. The theoretical calculation and the measured results indicate that both phases in the x = 0.4 sample possess the lowest lattice thermal conductivity. As a result, the dimensionless figure of merit ZT of this alloy is greater than that of the other compositions in the whole temperature range measured. A peak ZT of 1.0 at 750–800 K is obtained for this sample.
Efficient allocation of heterogeneous response times in information spreading process
Authors: Cui Ai-Xiang , Wang Wei , Tang Ming , Fu Yan , Liang Xiaoming , Do Younghae
Published: July 2014

Recently, the impacts of spatiotemporal heterogeneities of human activities on spreading dynamics have attracted extensive attention. In this paper, we intend to understand how the heterogeneous distribution of response times at the individual level influences information spreading. Based on the uncorrelated scale-free networks without degree-degree correlation, we study the susceptible-infected spreading dynamics with adjustable power-law response time distribution, and find that the stronger the heterogeneity of response times is, the faster the information spreading is in the early and middle stages. Following a given heterogeneity, the procedure of reducing the correlation between the response times and degrees of individuals can also accelerate the spreading dynamics in the early and middle stages. However, the dynamics in the late stage is slightly more complicated, and there is an optimal value of the full prevalence time (i.e., the time for full infection on a network) changing with the heterogeneity of response times and the response time-degree correlation, respectively. The optimal phenomena result from the efficient allocation of heterogeneous response times.
Passivation layer breakdown during laser-fired contact formation for photovoltaic devices
Authors: Raghavan A. , Palmer T. A. , DebRoy T.
Published: July 2014

Low resistance laser-fired ohmic contacts (LFCs) can be formed on the backside of Si-based solar cells using microsecond pulses. However, the impact of these longer pulse durations on the dielectric passivation layer is not clear. Retention of the passivation layer during processing is critical to ensure low recombination rates of electron-hole pairs at the rear surface of the device. In this work, advanced characterization tools are used to demonstrate that although the SiO2 passivation layer melts directly below the laser, it is well preserved outside the immediate LFC region over a wide range of processing parameters. As a result, low recombination rates at the passivation layer/wafer interface can be expected despite higher energy densities associated with these pulse durations.
Digestion of forages in the rumen is increased by the amount but not the type of protein supplement
Authors: Panjaitan T. , Quigley S. P. , McLennan S. R. , Swain A. J. , Poppi D. P.
Published: July 2014

Three polyester bag experiments were conducted with fistulated Bos indicus steers to determine the effect of the amount and type of nitrogen (N) supplement on the digestion rate of forages different in quality. In Experiment 1, test substrates were incubated in polyester bags in the rumen of steers fed ryegrass, pangola grass, speargrass and Mitchell grass hays in a 4 by 4 Latin-square design. In Experiment 2, test substrates were incubated in polyester bags in the rumen of steers fed speargrass hay supplemented with urea and ammonium sulfate (US), branched-chain amino acids with US (USAA), casein, cottonseed meal, yeast and Chlorella algae in a 7 by 3 incomplete Latin-square design. In Experiment 3, test substrates were incubated in polyester bags in the rumen of steers fed Mitchell grass hay supplemented with increasing amounts of US or Spirulina algae (Spirulina platensis). The test substrates used in all experiments were speargrass, Mitchell grass, pangola grass or ryegrass hays. Digestion rate of the ryegrass substrate was higher than that of the speargrass substrate (P < 0.05) in Experiment 1. Supplementation with various N sources increased the degradation rate and effective degradability of all incubated substrates above that apparent in Control steers (P < 0.05; Experiment 2). Supplementation of US and Spirulina increased degradation rate and effective degradability of ryegrass, pangola grass and Mitchell grass substrates above that apparent in Control steers (P < 0.05; Experiment 3). However, there was no further response on digestion rate of the substrates in increasing supplementation levels either for US or Spirulina. In conclusion, rate of digestion was affected by forage physical and anatomical properties. Supplementation with various N sources increased rate of digestion when the Control forage ration was very low in N but once a minimum level of N supplementation was reached, irrespective of form of N or other potential growth factors, there was no further increase in rate of digestion.
Effect of Intramolecular Hydrogen Bonds on the Gas-Phase Basicity of Guanidines
Authors: Glasovac Zoran , Eckert-Maksić Mirjana
Published: July 2014

Three series of novel trisubstituted guanidines containing at least one hydrogen bond accepting (HBA) group were modelled using B3LYP/6–311+G(2df,p)//B3LYP/6–31G(d) calculations. Their structure was modified by incorporating a variety of different HBA groups covering a wide range of hydrogen bond strengths. Calculated gas-phase basicities (GBs) ranged from 1035 to 1181 kJ mol–1 depending on the nature of the substituent. To rationalise changes in the GB, a correlation of GB against two independent variables (pKHB and σ4B) was conducted where pKHB served as the descriptor of the hydrogen bond strength and σ4B was introduced to describe changes in the GBs in the open-chain model systems, i.e. in the absence of intramolecular hydrogen bond (IMHB), caused by the electronic effect of the propyl-HBA substituent. A very good correlation of the calculated gas-phase basicities against these two independent variables was established for all three sets of the bases.
Remediating Fassbinder
Authors: Pellegrini David
Published: July 2014

Two stage productions based on screenplays by Rainer Werner Fassbinder— The Marriage of Maria Braun directed by Tomas Ostermeier and In a Year With 13 Moons directed by Robert Woodruff—span a range of possibilities for film-to-stage adaptations. Fassbinder provides an interesting case study because over the course of his career, he created numerous adaptations for the stage, screen, and television. While Ostermeier’s epic theatre adaptation re-situated Fassbinder within the context of German modernist and avant-garde theatre, Woodruff’s production demonstrated that live, intermedial performance is capable of reconciling Fassbinder’s practice of enfranchising multiple textualities, including the dramaturgical, theatrical, cinematic, and televisual codes of representation he was constantly re-deploying. Focusing on performative elements, such as acting style, mise-en-scene, and hypermediacy, as well as extra- and para-textual dimensions, this paper provides an overview of the aesthetic categories of production, reception, and intention as they pertain to theatrical adaptations of ‘art-house’ films.
Therapeutic use of anti-CTLA-4 antibodies
Authors: Blank Christian U. , Enk Alexander
Published: July 2014

Targeting CTLA-4 represents a new type of immunotherapeutic approach, namely immune checkpoint inhibition. Blockade of CTLA-4 by ipilimumab was the first strategy to achieve a significant clinical benefit for late-stage melanoma patients in two phase 3 trials. These results fueled the notion of immunotherapy being the breakthrough strategy for oncology in 2013. Subsequently, many trials have been set up to test various immune checkpoint modulators in malignancies, not only in melanoma. In this review, recent new ideas about the mechanism of action of CTLA-4 blockade, its current and future therapeutic use, and the intensive search for biomarkers for response will be discussed. Immune checkpoint blockade, targeting CTLA-4 and/or PD-1/PD-L1, is currently the most promising systemic therapeutic approach to achieve long-lasting responses or even cure in many types of cancer, not just in patients with melanoma.
Herschel/PACS observations of the host galaxy of GRB 031203
Authors: Symeonidis M. , Oates S. R. , de Pasquale M. , Page M. J. , Wiersema K. , Starling R. , Schady P. , Seymour N. , O'Halloran B.
Published: July 2014

We present Herschel/PACS observations of the nearby (z = 0.1055) dwarf galaxy that has hosted the long gamma-ray burst (LGRB) 031203. Using the PACS data, we have been able to place constraints on the dust temperature, dust mass, total infrared (IR) luminosity and IR-derived star formation rate (SFR) for this object. We find that the GRB host galaxy (GRBH) 031203 has a total IR luminosity of 3 × 1010 L⊙ placing it in the regime of the IR-luminous galaxy population. Its dust temperature and specific SFR are comparable to that of many high-redshift (z = 0.3–2.5) IR-detected GRB hosts (Tdust > 40 K; sSFR > 10 Gyr−1); however, its dust-to-stellar mass ratio is lower than what is commonly seen in IR-luminous galaxies. Our results suggest that GRBH 031203 is undergoing a strong starburst episode and its dust properties are different to those of local dwarf galaxies within the same metallicity and stellar mass range. Furthermore, our measurements place it in a distinct class to the well-studied nearby host of GRB 980425 (z = 0.0085), confirming the notion that GRB host galaxies can span a large range in properties even at similar cosmological epochs, making LGRBs an ideal tool in selecting samples of star-forming galaxies up to high redshift.
Phylogenetic Clades 6 and 8 of Enterohemorrhagic Escherichia coli O157:H7 With Particular stx Subtypes are More Frequently Found in Isolates From Hemolytic Uremic Syndrome Patients Than From Asymptomatic Carriers
Authors: Iyoda Sunao , Manning Shannon D. , Seto Kazuko , Kimata Keiko , Isobe Junko , Etoh Yoshiki , Ichihara Sachiko , Migita Yuji , Ogata Kikuyo , Honda Mikiko , Kubota Tsutomu , Kawano Kimiko , Matsumoto Kazutoshi , Kudaka Jun , Asai Norio , Yabata Junko , Tominaga Kiyoshi , Terajima Jun , Morita-Ishihara Tomoko , Izumiya Hidemasa , Ogura Yoshitoshi , Saitoh Takehito , Iguchi Atsushi , Kobayashi Hideki , Hara-Kudo Yukiko , Ohnishi Makoto , Arai Reiko , Kawase Masao , Asano Yukiko , Asoshima Nanami , Chiba Kazuki , Furukawa Ichiro , Kuroki Toshiro , Hamada Madoka , Harada Seiya , Hatakeyama Takashi , Hirochi Takashi , Sakamoto Yumiko , Hiroi Midori , Takashi Kanda , Horikawa Kazumi , Iwabuchi Kaori , Kameyama Mitsuhiro , Kasahara Hitomi , Kawanishi Shinya , Kikuchi Koji , Ueno Hiroyuki , Kitahashi Tomoko , Kojima Yuka , Konishi Noriko , Obata Hiromi , Kai Akemi , Kono Tomomi , Kurazono Takayuki , Matsumoto Masakado , Matsumoto Yuko , Nagai Yuhki , Naitoh Hideki , Nakajima Hiroshi , Nakamura Hiromi , Nakane Kunihiko , Nishi Keiko , Saitoh Etsuko , Satoh Hiroaki , Takamura Mitsuteru , Shiraki Yutaka , Tanabe Junichi , Tanaka Keiko , Tokoi Yuki , Yatsuyanagi Jun
Published: July 2014

Background.  Enterohemorrhagic Escherichia coli (EHEC) O157:H7 infection causes severe diseases such as bloody diarrhea and hemolytic uremic syndrome (HUS). Although EHEC O157:H7 strains have exhibited high genetic variability, their abilities to cause human diseases have not been fully examined.

Methods.  Clade typing and stx subtyping of EHEC O157:H7 strains, which were isolated in Japan during 1999–2011 from 269 HUS patients and 387 asymptomatic carriers (ACs) and showed distinct pulsed-field gel electrophoresis patterns, were performed to determine relationships between specific lineages and clinical presentation.

Results.  Clades 6 and 8 strains were more frequently found among the isolates from HUS cases than those from ACs (P = .00062 for clade 6, P < .0001 for clade 8). All clade 6 strains isolated from HUS patients harbored stx2a and/or stx2c, whereas all clade 8 strains harbored either stx2a or stx2a/stx2c. However, clade 7 strains were predominantly found among the AC isolates but less frequently found among the HUS isolates, suggesting a significant association between clade 7 and AC (P < .0001). Logistic regression analysis revealed that 0–9 year old age is a significant predictor of the association between clade 8 and HUS. We also found an intact norV gene, which encodes for a nitric oxide reductase that inhibits Shiga toxin activity under anaerobic condition, in all clades 1–3 isolates but not in clades 4–8 isolates.

Conclusions.  Early detection of EHEC O157:H7 strains that belonged to clades 6/8 and harbored specific stx subtypes may be important for defining the risk of disease progression in EHEC-infected 0- to 9-year-old children.
Searching for γ-ray pulsars among Fermi unassociated sources: 2FGL J1906.5+0720
Authors: Xing Yi , Wang Zhongxiang
Published: July 2014

We report the results from our analysis of the Fermi Large Area Telescope data for the Fermi unassociated source 2FGL J1906.5+0720, which is a high-ranked candidate pulsar. In order to better study our target, we first update the ephemeris for PSR J1907+0602, which is used to help remove any possible contamination due to strong emission from this nearby pulsar. From our analysis, 2FGL J1906.5+0720 is confirmed to have a significant low-energy cut-off at ∼ 1 GeV in its emission (14 σ–18 σ significance), consistent with those seen in young pulsars. We search for pulsations but no spin frequency signals are found in a frequency range of 0.5–32 Hz. No single model can fully describe the source's overall Fermi γ-ray spectrum, and the reason for this is the excess emission detected at energies of ≥ 4 GeV. The high-energy component possibly indicates emission from a pulsar wind nebula, when considering 2FGL J1906.5+0720 as a young pulsar. We conclude that 2FGL J1906.5+0720 is likely a pulsar based on the emission properties we have obtained, and observations at other energies are needed in order to confirm its pulsar nature.
Emergence of carbapenem-resistant Acinetobacter baumannii as the major cause of ventilator-associated pneumonia in intensive care unit patients at an infectious disease hospital in southern Vietnam
Authors: Nhu Nguyen Thi Khanh , Lan Nguyen Phu Huong , Campbell James I. , Parry Christopher M. , Thompson Corinne , Tuyen Ha Thanh , Hoang Nguyen Van Minh , Tam Pham Thi Thanh , Le Vien Minh , Nga Tran Vu Thieu , Nhu Tran Do Hoang , Van Minh Pham , Nga Nguyen Thi Thu , Thuy Cao Thu , Dung Le Thi , Yen Nguyen Thi Thu , Van Hao Nguyen , Loan Huynh Thi , Yen Lam Minh , Nghia Ho Dang Trung , Hien Tran Tinh , Thwaites Louise , Thwaites Guy , Chau Nguyen Van Vinh , Baker Stephen
Published: July 2014

Ventilator-associated pneumonia (VAP) is a serious healthcare-associated infection that affects up to 30 % of intubated and mechanically ventilated patients in intensive care units (ICUs) worldwide. The bacterial aetiology and corresponding antimicrobial susceptibility of VAP is highly variable, and can differ between countries, national provinces and even between different wards in the same hospital. We aimed to understand and document changes in the causative agents of VAP and their antimicrobial susceptibility profiles retrospectively over an 11 year period in a major infectious disease hospital in southern Vietnam. Our analysis outlined a significant shift from Pseudomonas aeruginosa to Acinetobacter spp. as the most prevalent bacteria isolated from quantitative tracheal aspirates in patients with VAP in this setting. Antimicrobial resistance was common across all bacterial species and we found a marked proportional annual increase in carbapenem-resistant Acinetobacter spp. over a 3 year period from 2008 (annual trend; odds ratio 1.656, P = 0.010). We further investigated the possible emergence of a carbapenem-resistant Acinetobacter baumannii clone by multiple-locus variable number tandem repeat analysis, finding a bla
OXA-23-positive strain that was associated with an upsurge in the isolation of this pathogen. We additionally identified a single bla
NDM-1-positive A. baumannii isolate. This work highlights the emergence of a carbapenem-resistant clone of A. baumannii and a worrying trend of antimicrobial resistance in the ICU of the Hospital for Tropical Diseases in Ho Chi Minh City, Vietnam.
Characterization of a dual-active enzyme, DcpA, involved in cyclic diguanosine monophosphate turnover in Mycobacterium smegmatis
Authors: Sharma Indra Mani , Prakash Sunita , Dhanaraman Thillaivillalan , Chatterji Dipankar
Published: July 2014

We have reported previously that the long-term survival of Mycobacterium smegmatis is facilitated by a dual-active enzyme MSDGC-1 (renamed DcpA), which controls the cellular turnover of cyclic diguanosine monophosphate (c-di-GMP). Most mycobacterial species possess at least a single copy of a DcpA orthologue that is highly conserved in terms of sequence similarity and domain architecture. Here, we show that DcpA exists in monomeric and dimeric forms. The dimerization of DcpA is due to non-covalent interactions between two protomers that are arranged in a parallel orientation. The dimer shows both synthesis and hydrolysis activities, whereas the monomer shows only hydrolysis activity. In addition, we have shown that DcpA is associated with the cytoplasmic membrane and exhibits heterogeneous cellular localization with a predominance at the cell poles. Finally, we have also shown that DcpA is involved in the change in cell length and colony morphology of M. smegmatis. Taken together, our study provides additional evidence about the role of the bifunctional protein involved in c-di-GMP signalling in M. smegmatis.
Expression noise facilitates the evolution of gene regulation
Authors: Wolf Luise , Silander Olin K. , van Nimwegen Erik
Published: July 2014

In studies of gene regulation, it is often tacitly assumed that the interactions between transcriptional regulators and their target promoters are finely tuned to ensure condition-appropriate gene expression of the targets. However, how natural selection might evolve such precise regulation from an initial state without regulation, is rarely discussed. In addition, the accuracy of gene regulation is affected by noise in gene expression [1]. Expression noise varies greatly across genes [2–5], suggesting that natural selection has affected noise levels, but the role of expression noise in gene regulation is currently poorly understood [6]. Here we present a combination of experimental evidence and theoretical modeling showing that the transmission of expression noise from regulators to their targets can function as a rudimentary form of gene regulation that facilitates the evolution of more finely tuned gene regulation. To assess how natural selection has affected transcriptional noise inE. coli, we evolved a large set of synthetic promoters under carefully controlled selective conditions and found, surprisingly, that nativeE. colipromoters show no signs of having been selected for minimizing their noise. Instead, a subset of native promoters, which are characterized by high expression plasticity and high numbers of regulatory inputs, show elevated noise levels. A general theoretical model, which recognizes that target genes are not only affected by the condition-dependent activities of their regulators, but also by the regulators’ noise, explains these observations. Noise transmission from regulators to their targets is favored by selection whenever regulation is imprecise, and may even constitute the main function of coupling a promoter to a regulator. Our theory provides a novel framework for understanding the evolution of gene regulation, demonstrating that in many situations expression noise is not the mere unwanted side-effect of regulatory interactions, but a beneficial function that is key to the evolvability of regulatory interactions.
Conservation of expression regulation throughout the animal kingdom
Authors: Kuhn Michael , Beyer Andreas
Published: July 2014

Following the increase in available sequenced genomes, tissue-specific transcriptomes are being determined for a rapidly growing number of highly diverse species. Traditionally, only the transcriptomes of related species with equivalent tissues have been compared. Such an analysis is much more challenging over larger evolutionary distances when complementary tissues cannot readily be defined. Here, we present a method for the cross-species mapping of tissue-specific and developmental gene expression patterns across a wide range of animals, including many non-model species. Our approach maps gene expression patterns between species without requiring the definition of homologous tissues. With the help of this mapping, gene expression patterns can be compared even across distantly related species. In our survey of 36 datasets across 27 species, we detected conserved expression programs on all taxonomic levels, both within animals and between the animals and their closest unicellular relatives, the choanoflagellates. We found that the rate of change in tissue expression patterns is a property of gene families. Our findings open new avenues of study for the comparison and transfer of knowledge between different species.
AtGEN1 and AtSEND1, Two Paralogs in Arabidopsis, Possess Holliday Junction Resolvase Activity
Authors: Bauknecht Markus , Kobbe Daniela
Published: July 2014

Holliday junctions (HJs) are physical links between homologous DNA molecules that arise as central intermediary structures during homologous recombination and repair in meiotic and somatic cells. It is necessary for these structures to be resolved to ensure correct chromosome segregation and other functions. In eukaryotes, including plants, homologs of a gene called XPG-like endonuclease1 (GEN1) have been identified that process HJs in a manner analogous to the HJ resolvases of phages, archaea, and bacteria. Here, we report that Arabidopsis (Arabidopsis thaliana), a eukaryotic organism, has two functional GEN1 homologs instead of one. Like all known eukaryotic resolvases, AtGEN1 and Arabidopsis single-strand DNA endonuclease1 both belong to class IV of the Rad2/XPG family of nucleases. Their resolvase activity shares the characteristics of the Escherichia coli radiation and UV sensitive C paradigm for resolvases, which involves resolving HJs by symmetrically oriented incisions in two opposing strands. This leads to ligatable products without the need for further processing. The observation that the sequence context influences the cleavage by the enzymes can be interpreted as a hint for the existence of sequence specificity. The two Arabidopsis paralogs differ in their preferred sequences. The precise cleavage positions observed for the resolution of mobile nicked HJs suggest that these cleavage positions are determined by both the substrate structure and the sequence context at the junction point.
Chloroplast Dysfunction Causes Multiple Defects in Cell Cycle Progression in the Arabidopsis crumpled leaf Mutant
Authors: Hudik Elodie , Yoshioka Yasushi , Domenichini Séverine , Bourge Mickaël , Soubigout-Taconnat Ludivine , Mazubert Christelle , Yi Dalong , Bujaldon Sandrine , Hayashi Hiroyuki , De Veylder Lieven , Bergounioux Catherine , Benhamed Moussa , Raynaud Cécile
Published: July 2014

The majority of research on cell cycle regulation is focused on the nuclear events that govern the replication and segregation of the genome between the two daughter cells. However, eukaryotic cells contain several compartmentalized organelles with specialized functions, and coordination among these organelles is required for proper cell cycle progression, as evidenced by the isolation of several mutants in which both organelle function and overall plant development were affected. To investigate how chloroplast dysfunction affects the cell cycle, we analyzed the crumpled leaf (crl) mutant of Arabidopsis (Arabidopsis thaliana), which is deficient for a chloroplastic protein and displays particularly severe developmental defects. In the crl mutant, we reveal that cell cycle regulation is altered drastically and that meristematic cells prematurely enter differentiation, leading to reduced plant stature and early endoreduplication in the leaves. This response is due to the repression of several key cell cycle regulators as well as constitutive activation of stress-response genes, among them the cell cycle inhibitor SIAMESE-RELATED5. One unique feature of the crl mutant is that it produces aplastidic cells in several organs, including the root tip. By investigating the consequence of the absence of plastids on cell cycle progression, we showed that nuclear DNA replication occurs in aplastidic cells in the root tip, which opens future research prospects regarding the dialogue between plastids and the nucleus during cell cycle regulation in higher plants.
Construction workplace discrimination
Authors: Kwok Wai Wong Johnny , H.Q. Lin Autumn
Published: July 2014

Purpose

– The construction industry has been criticized for cultural intolerance and its poor industrial image. The ethnically diverse construction workplace in Hong Kong (HK) is frequently noted as a place in which racial harassment and discrimination occurs. The purpose of this paper is to explore the discriminatory experiences and working conditions experienced by ethnic minority (EM) construction operatives in HK.

Design/methodology/approach

– A mixed-method approach was adopted, including a questionnaire survey and focus group discussions. The survey identified the thoughts of EM construction workers about racial discrimination and harassment in the workplace. The focus group discussions were aimed at further exploring the discriminatory practices on HK construction sites and possible discrimination-coping strategies.

Findings

– Questionnaire data from 100 EM site operatives and labourers mainly from Nepal and Pakistan, but some few from other Asian countries as well as, plus two focus group discussions suggested that indirect and subtle forms of racial harassment do exist on HK construction sites. The operatives sampled reported the existence of inequality of treatment in their working life. Communication difficulties caused by language barriers affect work relationships between different cultural groups on construction sites. EM site operatives tend to interact with workers of similar cultural and ethnic groups. On the corporate/company level, language support and translations of safety procedures notices and policies, should be established to bring staff together and promote a more inclusive and harmonious workplace.

Originality/value

– The paper offers insights into the racial discrimination problems in the construction sector in an Asian context, which has been less explored. It aims to provide insight into the EM construction worker's situation in HK as well as the need for developing workplace-specific policies that protect against discrimination and protect the rights of EM workers.
An investigation of service quality assessments across retail formats
Authors: Amorim Marlene , Bashashi Saghezchi Fatemeh
Published: July 2014

Purpose

– The purpose of this paper is to investigate the existence of differences in service quality assessments across distinct retail store formats. We address customers’ quality assessments for physical aspects, personal interactions, reliability and policies dimensions in hypermarkets and supermarkets to analyse the impacts for satisfaction and loyalty.

Design/methodology/approach

– The study builds on previous scales for service retail quality to develop a survey addressing customers of hypermarkets and supermarkets in Portugal. Data analysis addressed 248 complete questionnaires and involved statistical testing to explore differences in service quality expectations across retail store formats. The regression analysis was used to estimate impacts of each service quality dimension for customer satisfaction and loyalty intentions.

Findings

– The results support the existence of differences in customers’ service quality assessments across retail store formats, notably for the expectations about different quality dimensions. Differences were also observed on the impacts for customer satisfaction and loyalty, in particular for the dimensions of reliability and personal interaction.

Research limitations/implications

– The results suggest that managerial decisions regarding service in stores should be adjusted to the characteristics of each retail format. The generalizability of the results should be assessed by means of further investigation in other retail contexts.

Originality/value

– Retail customers patronize multiple types of retail stores that compete on diverse service attributes. Building on existing service measurement scales, this paper provides a contribution to understand customer’s quality assessments across distinct store types to inform retail quality and service differentiation strategies.
Preliminary insights and analysis into weapon enabled sexual offenders
Authors: Dawson Paul , M. Goodwill Alasdair , Dixon Louise
Published: July 2014

Purpose

– Weapon use is recognised as a key crime concern in England and Wales but has received relatively little focused research. The purpose of this paper is to examine weapon use by sexual offenders to develop new insights relevant for a police audience. Specifically, to examine the prevalence of weapons within sexual offenders and explore the differences between weapon and non-weapon enabled offenders on a range of characteristics.

Design/methodology/approach

– A sample of 1,618 single, stranger, solved, serious sexual assaults were provided by the Serious Crime Analysis Section of the Serious Organised Crime Agency. In all, 20 per cent of offenders were weapon enabled.

Findings

– There were almost no demographic differences between weapon enabled and non-weapon enabled offenders. In terms of the offence itself, there were many significant differences between the groups in terms of precautions used, victim involvement, injury, attack behaviours, victim approach and attack location. Further multivariate analysis revealed aspects of the offence that were associated with weapon use; these are broadly discussed within themes of violence and evidence of planning.

Originality/value

– The authors argue that an examination of weapon use is valuable in illustrating how offenders differ in their offence and provide insights for the investigation of such crime.
Critical thinkers and capable practitioners
Authors: Schoenberger-Orgad Michèle , Spiller Dorothy
Published: July 2014

Purpose

– Educating the students to be capable practitioners for the future suggests that teachers be visionaries and futurologists to identify the skills required for the communication needs of society. The purpose of this paper is to argue for a sustainable curriculum – one that meets the needs of the present and prepares students to meet the demands of the future. Such a curriculum identifies the importance of developing student capability in critical thinking and in research methodology. It is an approach in which discussion, research activities and peer assessment can help to develop these dispositions and prepare students for effective participation in work and society for the long term.

Design/methodology/approach

– The paper draws on the pedagogical literature on discussion-led learning for critical inquiry and the use of peer review and feedback to provide the theoretical framework for the paper. Response data were collected from a postgraduate public relations (PR) class where two initiatives were introduced.

Findings

– Student responses to discussion-led inquiry and peer review were positive and provided an excellent basis for ongoing critical practice in the workplace. By encouraging criticality through small interventions at the undergraduate level, postgraduate and entry-level practitioners will sustain strong critical thinking abilities to apply in the work place.

Research limitations/implications

– The initiatives were introduced in one year and reviewed and adapted for the second iteration. The postgraduate classes are small which limits the implications of the research recommendations and conclusions.

Practical implications

– By modelling the discussion process in class and encouraging students to articulate their thoughts and arguments, teachers are able to introduce learning moments and opportunities which can lead to further discussion. By these means, students learn to evaluate arguments and make ethical judgments about the practice of PR in a variety of different contexts.

Social implications

– Practising critical thinking skills, alongside the tactical vocational skills, provide future practitioners with the ability to extend their creativity in search of practical solutions to issues faced by society and organizations in the twenty-first century. University-educated graduates of PR can make a strong, ethical and creative contribution to society through constant questioning of basic assumptions and through their curiosity about power balances and issues. They will embrace technological innovation as another tool in the PR toolkit to engage stakeholders in creative ways.

Originality/value

– By using a range of pedagogical strategies, it is possible for teachers to promote a critically informed approach to practice. Students learn to question basic assumptions and biases and to develop strong intellectual skills. These, in turn, will provide the basis for ethical communication practices and contribute to new and creative ways of thinking about society and its communication needs.