bluuebunny/crossref_metadata_2025 huggingface dataset:
Accuracy evaluation of a Compton X-ray spectrometer with bremsstrahlung X-rays generated by a 6 MeV electron bunch
Authors: Kojima Sadaoki , Arikawa Yasunobu , Nishimura Yasuhiko , Togawa Hiromi , Zhang Zhe , Ikenouchi Takahito , Ozaki Tetsuo , Morace Alessio , Nagai Takahiro , Abe Yuki , Sakata Shouhei , Inoue Hiroaki , Utsugi Masaru , Nakai Mitsuo , Nishimura Hiroaki , Shiraga Hiroyuki , Kato Ryukou , Fujioka Shinsuke , Azechi Hiroshi
Published: October 2014

A Compton-scattering-based X-ray spectrometer is developed to obtain the energy distribution of fast electrons produced by intense laser and matter interactions. Bremsstrahlung X-rays generated by fast electrons in a material are used to measure fast electrons’ energy distribution in matter. In the Compton X-ray spectrometer, X-rays are converted into recoil electrons by Compton scattering in a converter made from fused silica glass, and a magnet-based electron energy analyzer is used to measure the energy distribution of the electrons that recoil in the direction of the incident X-rays. The spectrum of the incident X-rays is reconstructed from the energy distribution of the recoil electrons. The accuracy of this spectrometer is evaluated using a quasi-monoenergetic 6 MeV electron bunch that emanates from a linear accelerator. An electron bunch is injected into a 1.5 mm thick tungsten plate to produce bremsstrahlung X-rays. The spectrum of these bremsstrahlung X-rays is obtained in the range from 1 to 9 MeV. The energy of the electrons in the bunch is estimated using a Monte Carlo simulation of particle-matter interactions. The result shows that the spectrometer's energy accuracy is ±0.5 MeV for 6.0 MeV electrons.
Equation of State for Supercooled Water at Pressures up to 400 MPa
Authors: Holten Vincent , Sengers Jan V. , Anisimov Mikhail A.
Published: October 2014

An equation of state is presented for the thermodynamic properties of cold and supercooled water. It is valid for temperatures from the homogeneous ice nucleation temperature up to 300 K and for pressures up to 400 MPa, and can be extrapolated up to 1000 MPa. The equation of state is compared with experimental data for the density, expansion coefficient, isothermal compressibility, speed of sound, and heat capacity. Estimates for the accuracy of the equation are given. The melting curve of ice I is calculated from the phase-equilibrium condition between the proposed equation and an existing equation of state for ice I.
Investigating the solid-liquid phase transition of water nanofilms using the generalized replica exchange method
Authors: Lu Qing , Kim Jaegil , Farrell James D. , Wales David J. , Straub John E.
Published: October 2014

The generalized Replica Exchange Method (gREM) was applied to study a solid-liquid phase transition in a nanoconfined bilayer water system using the monatomic water (mW) model. Exploiting optimally designed non-Boltzmann sampling weights with replica exchanges, gREM enables an effective sampling of configurations that are metastable or unstable in the canonical ensemble via successive unimodal energy distributions across phase transition regions, often characterized by S-loop or backbending in the statistical temperature. Extensive gREM simulations combined with Statistical Temperature Weighted Histogram Analysis Method (ST-WHAM) for nanoconfined mW water at various densities provide a comprehensive characterization of diverse thermodynamic and structural properties intrinsic to phase transitions. Graph representation of minimized structures of bilayer water systems determined by the basin-hopping global optimization revealed heterogeneous ice structures composed of pentagons, hexagons, and heptagons, consistent with an increasingly ordered solid phase with decreasing density. Apparent crossover from a first-order solid-liquid transition to a continuous one in nanoconfined mW water with increasing density of the system was observed in terms of a diminishing S-loop in the statistical temperature, smooth variation of internal energies and heat capacities, and a characteristic variation of lateral radial distribution functions, and transverse density profiles across transition regions.
Quantum effects in intermediate-temperature dipole-dipole correlation-functions in the presence of an environment
Authors: Grossmann F.
Published: October 2014

We study thermal dipole-dipole correlation functions and their corresponding IR spectra in the presence of an intermediate temperature bath of harmonic oscillators. Whereas for a Morse oscillator without coupling to a heat bath, the quantum level structure is displayed in the spectrum, classical calculations show a broad, smeared out spectrum. In the presence of purely Ohmic dissipation already for extremely weak relaxation rate, the classical case is recovered. Using the HEOM approach of Tanimura and Wolynes [Phys. Rev. A 43, 4131 (1991)], we show that to observe some remnants of the level structure in the spectrum for moderate damping strength as well as intermediate temperatures, the dynamics has to be non-Markovian (Ohmic dissipation with cutoff).
Fully kinetic simulations of megajoule-scale dense plasma focus
Authors: Schmidt A. , Link A. , Welch D. , Meehan B. T. , Tang V. , Halvorson C. , May M. , Hagen E. C.
Published: October 2014

Dense plasma focus (DPF) Z-pinch devices are sources of copious high energy electrons and ions, x-rays, and neutrons. Megajoule-scale DPFs can generate 1012 neutrons per pulse in deuterium gas through a combination of thermonuclear and beam-target fusion. However, the details of the neutron production are not fully understood and past optimization efforts of these devices have been largely empirical. Previously, we reported on the first fully kinetic simulations of a kilojoule-scale DPF and demonstrated that both kinetic ions and kinetic electrons are needed to reproduce experimentally observed features, such as charged-particle beam formation and anomalous resistivity. Here, we present the first fully kinetic simulation of a MegaJoule DPF, with predicted ion and neutron spectra, neutron anisotropy, neutron spot size, and time history of neutron production. The total yield predicted by the simulation is in agreement with measured values, validating the kinetic model in a second energy regime.
Study of mass and cluster flux in a pulsed gas system with enhanced nanoparticle aggregation
Authors: Drache Steffen , Stranak Vitezslav , Hubicka Zdenek , Berg Florian , Tichy Milan , Helm Christiane A. , Hippler Rainer
Published: October 2014

The paper is focused on investigation of enhanced metal (Cu) cluster growth in a source of Haberland's type using pulsed gas aggregation. The aggregation Ar gas was delivered into the cluster source in a pulse regime, which results in the formation of well pronounced aggregation pressure peaks. The pressure peaks were varied by varying the different pulse gas frequency at the same mean pressure kept for all experiments. Hence, we were able to study the effect of enhanced aggregation pressure on cluster formation. Time-resolved measurements of cluster mass distribution were performed to estimate the mass and particle flux. The paper demonstrates that pulse gas aggregation influences growth of Cu nanoparticles, i.e., cluster mass/size, mass flux, and particle flux emitted from the cluster source. It was found that cluster mass related quantities are strongly influenced by pulsed gas frequency; the highest value of mass flux appears at the most pronounced pressure peaks. On the other hand, the particle flux depends only slightly on the gas pulse frequency. The explanation based on cooling and thermalization of sputtered particles is discussed in the paper.
Large permeabilities of hourglass nanopores: From hydrodynamics to single file transport
Authors: Gravelle Simon , Joly Laurent , Ybert Christophe , Bocquet Lydéric
Published: October 2014

In fluid transport across nanopores, there is a fundamental dissipation that arises from the connection between the pore and the macroscopic reservoirs. This entrance effect can hinder the whole transport in certain situations, for short pores and/or highly slipping channels. In this paper, we explore the hydrodynamic permeability of hourglass shape nanopores using molecular dynamics (MD) simulations, with the central pore size ranging from several nanometers down to a few Angströms. Surprisingly, we find a very good agreement between MD results and continuum hydrodynamic predictions, even for the smallest systems undergoing single file transport of water. An optimum of permeability is found for an opening angle around 5°, in agreement with continuum predictions, yielding a permeability five times larger than for a straight nanotube. Moreover, we find that the permeability of hourglass shape nanopores is even larger than single nanopores pierced in a molecular thin graphene sheet. This suggests that designing the geometry of nanopores may help considerably increasing the macroscopic permeability of membranes.
Graphene: A partially ordered non-periodic solid
Authors: Wei Dongshan , Wang Feng
Published: October 2014

Molecular dynamics simulations were performed to study the structural features of graphene over a wide range of temperatures from 50 to 4000 K using the PPBE-G potential [D. Wei, Y. Song, and F. Wang, J. Chem. Phys. 134, 184704 (2011)]. This potential was developed by force matching the Perdew-Burke-Ernzerhof (PBE) exchange correlation functional and has been validated previously to provide accurate potential energy surface for graphene at temperatures as high as 3000 K. Simulations with the PPBE‑G potential are the best available approximation to a direct Car-Parrinello Molecular Dynamics study of graphene. One advantage of the PBE-G potential is to allow large simulation boxes to be modeled efficiently so that properties showing strong finite size effects can be studied. Our simulation box contains more than 600 000 C atoms and is one of the largest graphene boxes ever modeled. With the PPBE-G potential, the thermal-expansion coefficient is negative up to 4000 K. With a large box and an accurate potential, the critical exponent for the scaling properties associated with the normal-normal and height-height correlation functions was confirmed to be 0.85. This exponent remains constant up to 4000 K suggesting graphene to be in the deeply cooled regime even close to the experimental melting temperature. The reduced peak heights in the radial distribution function of graphene show an inverse power law dependence to distance, which indicates that a macroscopic graphene sheet will lose long-range crystalline order as predicted by the Mermin-Wagner instability. Although graphene loses long-range translational order, it retains long range orientational order as indicated by its orientational correlation function; graphene is thus partially ordered but not periodic.
Nonlinear electrophoresis of ideally polarizable particles
Authors: Figliuzzi B. , Chan W. H. R. , Moran J. L. , Buie C. R.
Published: October 2014

We focus in this paper on the nonlinear electrophoresis of ideally polarizable particles. At high applied voltages, significant ionic exchange occurs between the electric double layer, which surrounds the particle, and the bulk solution. In addition, steric effects due to the finite size of ions drastically modify the electric potential distribution in the electric double layer. In this situation, the velocity field, the electric potential, and the ionic concentration in the immediate vicinity of the particle are described by a complicated set of coupled nonlinear partial differential equations. In the general case, these equations must be solved numerically. In this study, we rely on a numerical approach to determine the electric potential, the ionic concentration, and the velocity field in the bulk solution surrounding the particle. The numerical simulations rely on a pseudo-spectral method which was used successfully by Chu and Bazant [J. Colloid Interface Sci. 315(1), 319–329 (2007)] to determine the electric potential and the ionic concentration around an ideally polarizable metallic sphere. Our numerical simulations also incorporate the steric model developed by Kilic et al. [Phys. Rev. E 75, 021502 (2007)] to account for crowding effects in the electric double layer, advective transport, and for the presence of a body force in the bulk electrolyte. The simulations demonstrate that surface conduction significantly decreases the electrophoretic mobility of polarizable particles at high zeta potential and at high applied electric field. Advective transport in the electric double layer and in the bulk solution is also shown to significantly impact surface conduction.
Photo-ionization and residual electron effects in guided streamers
Authors: Wu S. , Lu X. , Liu D. , Yang Y. , Pan Y. , Ostrikov K.
Published: October 2014

Complementary experiments and numerical modeling reveal the important role of photo-ionization in the guided streamer propagation in helium-air gas mixtures. It is shown that the minimum electron concentration ∼108 cm−3 is required for the regular, repeated propagation of the plasma bullets, while the streamers propagate in the stochastic mode below this threshold. The stochastic-to-regular mode transition is related to the higher background electron density in front of the propagating streamers. These findings help improving control of guided streamer propagation in applications from health care to nanotechnology and improve understanding of generic pre-breakdown phenomena.
Self-focusing of circularly polarized laser pulse propagating through a magnetized non-Maxwellian plasma
Authors: Sepehri Javan N.
Published: October 2014

Self-focusing of an intense circularly polarized laser pulse propagating through a magnetized non-Maxwellian plasma is investigated. Based on a relativistic two-fluid model, nonlinear equation describing dynamics of the slowly varying amplitude is obtained. The evolution of laser spot size is studied and effect of non-Maxwellian distribution of charge density on the spot size is considered. It is shown that the existence of super-thermal particles leads to the enhancement of the self-focusing quality of plasma.
Investigation of interface states distribution in metal-oxide-semiconductor structures with very thin oxides by acoustic spectroscopy
Authors: Bury P. , Bellan I. , Kobayashi H. , Takahashi M. , Matsumoto T.
Published: October 2014

New technique of acoustic spectroscopy to study interface states in metal-oxide-semiconductor (MOS) structures with a very thin oxide layer based on the acoustoelectric effect resulting from the interaction between the longitudinal acoustic wave and semiconductor-insulator interface is presented. The essential principles and theoretical background of this acoustic spectroscopy technique that can determine the interface states distribution from the measured acoustoelectric response signal as a function of gate voltage (Uac-Ug characteristics) are described. The results obtained on the representative set of MOS structures prepared on both n- and p-type Si substrates by nitric acid oxidation of Si technology and undergone also some thermal treatment demonstrate that the introduced technique of acoustic spectroscopy can be a very useful tool for the interface states characterization.
Ductile-to-brittle transition in spallation of metallic glasses
Authors: Huang X. , Ling Z. , Dai L. H.
Published: October 2014

In this paper, the spallation behavior of a binary metallic glass Cu50Zr50 is investigated with molecular dynamics simulations. With increasing the impact velocity, micro-voids induced by tensile pulses become smaller and more concentrated. The phenomenon suggests a ductile-to-brittle transition during the spallation process. Further investigation indicates that the transition is controlled by the interaction between void nucleation and growth, which can be regarded as a competition between tension transformation zones (TTZs) and shear transformation zones (STZs) at atomic scale. As impact velocities become higher, the stress amplitude and temperature rise in the spall region increase and micro-structures of the material become more unstable. Therefore, TTZs are prone to activation in metallic glasses, leading to a brittle behavior during the spallation process.
Landau levels of the C-exciton in CuInSe2 studied by magneto-transmission
Authors: Yakushev M. V. , Rodina A. V. , Shuchalin G. M. , Seisian R. P. , Abdullaev M. A. , Rockett A. , Zhivulko V. D. , Mudryi A. V. , Faugeras C. , Martin R. W.
Published: October 2014

The electronic structure of the solar cell absorber CuInSe2 is studied using magneto-transmission in thin polycrystalline films at magnetic fields up to 29 T. A, B, and C free excitons are resolved in absorption spectra at zero field and a Landau level fan generated by diamagnetic exciton recombination is observed for fields above 7 T. The dependence of the C band exciton binding energy on magnetic fields, calculated using a hydrogenic approximation, is used to determine the C exciton Rydberg at 0 T (8.5 meV), band gap (1.2828 eV), and hole effective mass mso = (0.31 ± 0.12)m0 for the C valence sub-band.
Hydrogen Bonding of O-Ethylxanthate Compounds and Neutron Structural Determination of C–H···S Interactions
Authors: Macreadie Lauren K. , Edwards Alison J. , Chesman Anthony S. R. , Turner David R.
Published: October 2014

A range of ethylxanthate (EtXn) salts, containing either protic or aprotic cations (guanidinium (1), methylammonium (2), dimethylammonium (3), trimethylammonium (4), tetramethylammonium (5), tetraethylammonium (6), and tetrapropylammonium (7)), have been synthesised and structurally characterised. The cations in these compounds differ in their degree of hydrogen-bonding ability, i.e. the number of donor groups, with significant structural consequences. Compounds 1–4 contain cations that are able to form N–H···S hydrogen bonds, with six, three, two, and one donor groups in 1–4 respectively. The number of donor atoms affects greatly the dimensionality of the hydrogen-bonding networks in the solid state. The structure of 1 has a 3-D hydrogen-bonding network, 2 and 3 form 2-D sheets and 1-D chains respectively, whereas the lone NH donor group in 4 has strong hydrogen bonding only within a discrete cation–anion pair. The tetraalkylammonium salts 5–7 have no strong hydrogen bonding, with only C–H···S and C–H···O interactions possible. To determine unambiguously the presence of such interactions, single-crystal Laue neutron diffraction data were obtained for compound 5, providing a fully anisotropic model, which can be used to rationalise potential close interactions in the other structures. The neutron structure of 5 confirms the existence of C–H···S hydrogen bonds, with the H···S distance falling well within the sum of the van der Waals radii of the atoms. The close-packing in 5–7 is mediated solely through these weak interactions, with the size of the cations influencing the structures.
Persistence of in-stream waterholes in ephemeral rivers of tropical northern Australia and potential impacts of climate change
Authors: McJannet David , Marvanek Steve , Kinsey-Henderson Anne , Petheram Cuan , Wallace Jim
Published: October 2014

Many northern Australian rivers have limited or non-existent dry season flow and rivers tend to dry to a series of pools, or waterholes, which become particularly important refugial habitat for aquatic biota during the periods between streamflow events. The present study developed techniques to identify in-stream waterholes across large and inaccessible areas of the Flinders and Gilbert catchments using Landsat imagery. Application of this technique to 400 scenes between 2003 and 2010 facilitated the identification of key waterhole refugia that are likely to persist during all years. Relationships for predicting total waterhole area from streamflow characteristics were produced for four river reaches. Using these relationships and streamflow predictions based upon climate data scaled using 15 global climate models, the potential impacts of future climate on waterhole persistence was assessed. Reductions in waterhole area of more than 60% were modelled in some years under drier scenarios and this represents a large reduction in available habitat for areas that already have limited in-stream refugia. Conversely, under wetter future climates the total area of waterholes increased. The approach developed here has applicability in other catchments, both in Australia and globally, and for assessing the impacts of changed flow resulting from water resource development.
Chapter 5. Prosody and autism
Authors: Arciuli Joanne
Published: October 2014

This chapter focuses on prosodic processing in individuals with autism spectrum disorders (ASD). An overview of key studies linking prosodic difficulties with ASD is provided. Methods reviewed include behavioural assessment, acoustic analyses, electrophysiological measures, and brain imaging. It is difficult to draw strong conclusions from previous research as there has been little consistency across studies in terms of the types of prosody that were examined, whether or not both comprehension and production of prosody were investigated, and the nature and size of the samples that were assessed. There is consensus that only some individuals with ASD experience problems with prosody. Importantly, different types of prosodic impairment have been observed across individuals with ASD and it seems likely that these are associated with different causal mechanisms. Some possible mechanisms underpinning prosodic impairment that have been put forward over the years include a cognitive deficit relating to Theory of Mind, motor speech impairment, lack of social motivation to align one’s speech with others, atypical audio-vocal regulation, and deficient pitch encoding. Future research endeavours should include increased effort to pinpoint causal mechanisms and explore targeted remediation of prosodic difficulties in individuals with ASD.
Language ideology and shifting representations of linguistic threats
Authors: Salö Linus
Published: October 2014

This chapter presents a sociological account of the language ideological representations underpinning discourses about perceived threats from English in Sweden. The objective is to contextualize the conceptual history of “domain loss” within Sweden’s field of language planning, in conjunction with crossing discourses about minority languages and EU membership. With Bourdieu, the safeguarding of Swedish is comprehended as linked to struggles where the role of the nation-state is set in flux, opening up linguistic markets beyond its control. As a product of the relation between agents’ habitus and the field, domain loss has served to legitimize discourses about the disestablishment of the national language regime, which is interpreted as a strategy to defend the market into which agents have invested capital.
Local majority and minority languages and English in the university
Authors: Lindström Jan , Sylvin Jenny
Published: October 2014

This study explores the usage and demand for local languages and English in a range of universities in Nordic countries. The University of Helsinki is in focus because of its bilingual status with two national languages, which have an official but not an equal position in practice. This research site was compared with five other universities working on a unilingual or multilingual basis. The study reveals tensions between official language policies and grassroots practices; language choice also creates tensions between national and global sciences. While official language policies may be soft steering instruments, they safeguard the presence of a non-default language. However, the increasing presence of English challenges traditional university language policies, calling for a reevaluation of them.
Ideologies in Iceland
Authors: Kristinsson Ari Páll
Published: October 2014

The author shows that while Iceland’s protectionist language ideologies are deeply rooted as to the forms of Icelandic, Icelanders are more pragmatic when it comes to questions of language choice. It is therefore not contradictory that English is increasingly used in Icelandic academia, even if this is a purist speech community. The chapter draws on data on purist language attitudes and practices concerning the native linguistic code, and on practices that reveal that increased use of English in Iceland, notably in tertiary education and research, is popularly accepted as natural. Therefore, recent official language policies (in 2009) and legislation (in 2011), aiming to restrict the use of English at Icelandic universities, are not likely to be effective in the long run.
The Importance of Juvenile Migration Tactics to Adult Recruitment in Stream‐Type Chinook Salmon Populations
Authors: Copeland Timothy , Venditti David A. , Barnett Bruce R.
Published: October 2014

The existence of multiple migration tactics within a population has been observed for several fish species, and they may contribute differentially to adult recruitment. Relative contribution by juveniles using the same habitats on different schedules is variable; therefore, understanding and conserving this diversity should be important to fisheries managers. We investigated adult recruitment by two distinct juvenile migration tactics in several spawning populations of stream‐type Chinook Salmon Oncorhynchus tshawytscha in Idaho: those leaving the spawning grounds as subyearlings during June through November (downstream rearing, or DSR, type) and those emigrating from natal areas 1 year after emergence (natal reach rearing, or NRR, type). The DSR type had greater juvenile abundance in all populations, although the NRR type exhibited better survival from the natal reach to the migratory corridor. The DSR type had greater survival from smoltification to adult return to freshwater compared with the NRR type. More DSR emigrants than NRR emigrants returned to freshwater as adults, although the difference was influenced by cohort and population. Adult recruits to stream‐type Chinook Salmon populations in Idaho are comprised mostly of DSR emigrants, i.e., fish that dispersed from their natal habitats and reared in reaches downstream. This finding is ubiquitous, although the size of the effect depends on cohort and population. We demonstrated that juvenile Chinook Salmon in Idaho do indeed use downstream rearing habitats effectively, thereby increasing recruitment of adults back to the spawning gravels in these populations. This study illustrates how dispersive life histories are essential to achieve the full productive potential of migratory stream fish populations.

Received March 31, 2014; accepted July 16, 2014
The early 1960s as a cultural space: a microhistory of Ukraine's generation of cultural rebels
Authors: Yekelchyk Serhy
Published: October 2014

This article analyzes the early stage of the Ukrainian “sixtiers” movement as a semi-autonomous space of cultural expression that was tolerated by the authorities and defined, developed, and inhabited by young Ukrainian intellectuals. In contrast to present-day Ukrainian representations of the sixtiers as a force acting in opposition to the Soviet regime, the spatial angle employed here reveals an ambiguous relationship with official institutions. The Ukrainian Komsomol organization in particular appears to be both a controlling and an enabling agent that, together with the Writers' Union, provided meeting venues for the sixtiers until the mid-1960s. This complex symbiotic relationship continued even after some creative youth pioneered the first attempts to claim public space for cultural events without the authorities' permission. The cultural terrain inhabited by young Ukrainian intellectuals was not fully separate from mainstream Soviet Ukrainian culture or in opposition to it, although their vibrant cultural space also reached into a world of non-conformist culture unregulated by the state. A series of government crackdowns beginning in the mid-1960s dramatically shrank this open, ambivalent space of semi-free cultural expression, imposing firm boundaries and forcing intellectuals to make political choices.
Using Spatial Resampling to Assess Redd Count Survey Length Requirements for Pacific Lamprey
Authors: Mayfield M. P. , Schultz L. D. , Wyss L. A. , Colvin M. E. , Schreck C. B.
Published: October 2014

Pacific Lamprey Entosphenus tridentatus has declined across its range along the West Coast of North America, and an understanding of all life history phases is needed to address population recovery. Spawning surveys (redd counts) are common tools currently used to monitor returning adult salmonids, but such methodologies are in their infancy for Pacific Lamprey. Our objective was to assess the minimum spawning survey distance required to detect the presence of Pacific Lamprey redds and obtain precise redd density estimates from these data. To do this, we statistically resampled existing spawning locations of Pacific Lamprey collected during spawning surveys in four streams of the Willamette River Basin, Oregon, during spring of 2013. We found that the minimum survey distance for Pacific Lamprey redd detection was inversely related to the observed redd density and was always less than 1.2 km. Survey distance requirements to obtain precise redd counts (±20% of observed redd densities) were also inversely related to redd density and habitat availability, and varied between 1.3 km and 13.7 km. Our results suggest that spawning surveys are a potential tool for monitoring adult Pacific Lamprey abundance, but the specific objectives of the monitoring programs and acknowledgment of unknowns must be considered prior to implementation into recovery plans.

Received January 2, 2014; accepted May 19, 2014
Model theory and the Tannakian formalism
Authors: Kamensky Moshe
Published: October 2014

We draw the connection between the model theoretic notions of internality and the binding group on one hand, and the Tannakian formalism on the other.

More precisely, we deduce the fundamental results of the Tannakian formalism by associating to a Tannakian category a first order theory, and applying the results on internality there. We then formulate the notion of a differential tensor category, which axiomatises the category of differential representations of differential linear groups, and show how the model theoretic techniques can be used to deduce the analogous results in that context.
Dyck’s surfaces, systoles, and capacities
Authors: Katz Mikhail , Sabourau Stéphane
Published: October 2014

We prove an optimal systolic inequality for nonpositively curved Dyck’s surfaces. The extremal surface is flat with eight conical singularities, six of angle 

ϑ
\vartheta

and two of angle 

9
π
−
3
ϑ

9 \pi -3 \vartheta

for a suitable 

ϑ
\vartheta

with

cos
⁡
(
ϑ
)
∈

Q

(

19

)

\cos (\vartheta )\in \mathbb {Q}(\sqrt {19})

. Relying on some delicate capacity estimates, we also show that the extremal surface is not conformally equivalent to the hyperbolic Dyck’s surface with maximal systole, yielding a first example of systolic extremality with this behavior.
Local invariants of isogenous elliptic curves
Authors: Dokchitser Tim , Dokchitser Vladimir
Published: October 2014

We investigate how various invariants of elliptic curves, such as the discriminant, Kodaira type, Tamagawa number and real and complex periods, change under an isogeny of prime degree

p
p

. For elliptic curves over

l
l

-adic fields, the classification is almost complete (the exception is wild potentially supersingular reduction when

l
=
p

l=p

), and is summarised in a table.
NOVA: a software to analyze complexome profiling data
Authors: Giese Heiko , Ackermann Jörg , Heide Heinrich , Bleier Lea , Dröse Stefan , Wittig Ilka , Brandt Ulrich , Koch Ina
Published: October 2014

Summary: We introduce nova , a software for the analysis of complexome profiling data. nova supports the investigation of the composition of complexes, cluster analysis of the experimental data, visual inspection and comparison of experiments and many other features.

Availability and implementation:  nova is licensed under the Artistic License 2.0. It is freely available at http://www.bioinformatik.uni-frankfurt.de . nova requires at least Java 7 and runs under Linux, Microsoft Windows and Mac OS.

Contact:  ina.koch@bioinformatik.uni-frankfurt.de
PDB-wide collection of binding data: current status of the PDBbind database
Authors: Liu Zhihai , Li Yan , Han Li , Li Jie , Liu Jie , Zhao Zhixiong , Nie Wei , Liu Yuchen , Wang Renxiao
Published: October 2014

Motivation: Molecular recognition between biological macromolecules and organic small molecules plays an important role in various life processes. Both structural information and binding data of biomolecular complexes are indispensable for depicting the underlying mechanism in such an event. The PDBbind database was created to collect experimentally measured binding data for the biomolecular complexes throughout the Protein Data Bank (PDB). It thus provides the linkage between structural information and energetic properties of biomolecular complexes, which is especially desirable for computational studies or statistical analyses.

Results: Since its first public release in 2004, the PDBbind database has been updated on an annual basis. The latest release (version 2013) provides experimental binding affinity data for 10 776 biomolecular complexes in PDB, including 8302 protein–ligand complexes and 2474 other types of complexes. In this article, we will describe the current methods used for compiling PDBbind and the updated status of this database. We will also review some typical applications of PDBbind published in the scientific literature.

Availability and implementation: All contents of this database are freely accessible at the PDBbind-CN Web server at http://www.pdbbind-cn.org/ .

Contact:  wangrx@mail.sioc.ac.cn .

Supplementary information:  Supplementary data are available at Bioinformatics online.
The Fungal Cell-Wall Integrity MAPK Cascade Is Crucial for Hyphal Network Formation and Maintenance of Restrictive Growth of Epichloë festucae in Symbiosis With Lolium perenne
Authors: Becker Yvonne , Eaton Carla J. , Brasell Emma , May Kimberley J. , Becker Matthias , Hassing Berit , Cartwright Gemma M. , Reinhold Leonie , Scott Barry
Published: October 2014

Epichloë festucae is a mutualistic symbiont that systemically colonizes the intercellular spaces of Lolium perenne leaves to form a highly structured and interconnected hyphal network. In an Agrobacterium tumefaciens T-DNA forward genetic screen, we identified a mutant TM1066 that had a severe host interaction phenotype, causing stunting and premature senescence of the host. Molecular analysis revealed that the mutation responsible for this phenotype was in the cell-wall integrity (CWI) mitogen-activated protein kinase kinase (MAPKK), mkkA. Mutants generated by targeted deletion of the mkkA or the downstream mpkA kinase recapitulated the phenotypes observed for TM1066. Both mutants were defective in hyphal cell–cell fusion, formed intrahyphal hyphae, had enhanced conidiation, and showed microcyclic conidiation. Transmission electron microscopy and confocal microscopy analysis of leaf tissue showed that mutant hyphae were more abundant than the wild type in the intercellular spaces and colonized the vascular bundles. Hyphal branches failed to fuse but, instead, grew past one another to form bundles of convoluted hyphae. Mutant hyphae showed increased fluorescence with AF488-WGA, indicative of increased accessibility of chitin, a hypothesis supported by changes in the cell-wall ultrastructure. These results show that the CWI MAPK pathway is a key signaling pathway for controlling the mutualistic symbiotic interaction between E. festucae and L. perenne.
Spongiibacterium pacificum sp. nov., isolated from seawater of South Pacific Gyre and emended description of the genus Spongiibacterium
Authors: Gao Xin , Zhang Zenghu , Dai Xiaofeng , Zhang Xiao-Hua
Published: October 2014

A Gram-stain-negative, strictly aerobic, non-flagellated, non-gliding, oxidase-positive and yellow-pigmented rod-shaped bacterium, designated strain SW169T, was isolated from a surface seawater sample collected from the South Pacific Gyre (27° 55′ S 123° 10′ W) during the Integrated Ocean Drilling Program (IODP) Expedition 329. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain SW169T belonged to the genus

Spongiibacterium

and showed the highest 16S rRNA gene sequence similarity with

Spongiibacterium flavum

A11T (95.9 %). It showed 16S rRNA gene sequence similarities of 93.2–94.8 % with members of the genera

Croceitalea

and

Flagellimonas

in the family

Flavobacteriaceae

. Optimal growth occurred in the presence of 3–4 % (w/v) NaCl, at pH 8.0 and at 28 °C. The DNA G+C content of strain SW169T was 43.3 mol%. The major fatty acids were iso-C15 : 1 G, iso-C15 : 0, iso-C17 : 0 3-OH, iso-C15 : 0 3-OH and summed feature 3 (comprising C16 : 1ω7c and/or C16 : 1ω6c,). The major respiratory quinone was menaquinone-6. The major polar lipids were phosphatidylethanolamine, one unidentified aminolipid and one unidentified lipid. On the basis of the polyphasic analyses, strain SW169T is considered to represent a novel species of the genus

Spongiibacterium

, for which the name Spongiibacterium pacificum sp. nov. is proposed. The type strain is SW169T ( = JCM 18379T = LMG 26997T). An emended description of the genus

Spongiibacterium

is also provided.
CPSF30 and Wdr33 directly bind to AAUAAA in mammalian mRNA 3′ processing
Authors: Chan Serena L. , Huppertz Ina , Yao Chengguo , Weng Lingjie , Moresco James J. , Yates John R. , Ule Jernej , Manley James L. , Shi Yongsheng
Published: October 2014

AAUAAA is the most highly conserved motif in eukaryotic mRNA polyadenylation sites and, in mammals, is specifically recognized by the multisubunit CPSF (cleavage and polyadenylation specificity factor) complex. Despite its critical functions in mRNA 3′ end formation, the molecular basis for CPSF–AAUAAA interaction remains poorly defined. The CPSF subunit CPSF160 has been implicated in AAUAAA recognition, but direct evidence has been lacking. Using in vitro and in vivo assays, we unexpectedly found that CPSF subunits CPSF30 and Wdr33 directly contact AAUAAA. Importantly, the CPSF30–RNA interaction is essential for mRNA 3′ processing and is primarily mediated by its zinc fingers 2 and 3, which are specifically targeted by the influenza protein NS1A to suppress host mRNA 3′ processing. Our data suggest that AAUAAA recognition in mammalian mRNA 3′ processing is more complex than previously thought and involves multiple protein–RNA interactions.
Crystal structure of 4-acetamidobenzoic acid monohydrate
Authors: Cai Wen-Juan , Chi Shao-Ming , Kou Jun-Feng , Liu Feng-Yi
Published: October 2014

In the title compound, C9H9NO3·H2O, the plane of the acetamide group is oriented at 20.52 (8)° with respect to the benzene ring, whereas the plane of the carboxylic acid group is essentially coplanar with the benzene ring [maximum deviation = 0.033 (1) Å]. In the crystal, classical O—H...O and N—H...O hydrogen bonds and weak C—H...O hydrogen bonds link the organic molecules and water molecules of crystallization into a three-dimensional supramolecular architecture.
Crystal structure of 3-(4-bromophenylsulfonyl)-2,5,6-trimethyl-1-benzofuran
Authors: Choi Hong Dae , Lee Uk
Published: October 2014

In the title compound, C17H15BrO3S, the dihedral angle between the planes of the benzofuran ring system [r.m.s. deviation = 0.015 (2) Å] and the 4-bromophenyl ring is 89.29 (6)°. In the crystal, molecules are linked into a chain along theb-axis direction by C—H...π hydrogen bonds and C—Br...π [3.626 (1) Å] interactions.
Use of bond-valence sums in modelling the diffuse scattering from PZN (PbZn1/3Nb2/3O3)
Authors: Whitfield R. E. , Welberry T. R. , Paściak M. , Goossens D. J.
Published: October 2014

This work extends previous efforts to model diffuse scattering from PZN (PbZn1/3Nb2/3O3). Earlier work [Welberryet al.(2005).J. Appl. Cryst.38, 639–647; Welberryet al.(2006).Phys. Rev. B,74, 224108] is highly prescriptive, using Monte Carlo simulation with very artificial potentials to induce short-range-order structures which were deduced as necessary from inspection of the data. While this gives valid results for the nature of the local structure, it does not strongly relate these structures to underlying crystal chemistry. In that work, the idea of the bond-valence sum was used as a guide to the expected behaviour of the atoms. This paper extends the use of the bond-valence sum from a qualitative guide to becoming a key aspect of the potential experienced by the atoms, through the idea of the global instability index, whose square has been shown to be proportional to the density functional theory energy of some systems when close to the minimum energy configuration.
A depth camera based approach for automatic control of video cameras in lecture halls
Authors: Winkler Michael , Michael Höver Kai , Mühlhäuser Max
Published: October 2014

Purpose

– The purpose of this study is to present a depth information-based solution for automatic camera control, depending on the presenter’s moving positions. Talks, presentations and lectures are often captured on video to give a broad audience the possibility to (re-)access the content. As presenters are often moving around during a talk, it is necessary to steer recording cameras.

Design/methodology/approach

– We use depth information from Kinect to implement a prototypical application to automatically steer multiple cameras for recording a talk.

Findings

– We present our experiences with the system during actual lectures at a university. We found out that Kinect is applicable for tracking a presenter during a talk robustly. Nevertheless, our prototypical solution reveals potential for improvements, which we discuss in our future work section.

Originality/value

– Tracking a presenter is based on a skeleton model extracted from depth information instead of using two-dimensional (2D) motion- or brightness-based image processing techniques. The solution uses a scalable networking architecture based on publish/subscribe messaging for controlling multiple video cameras.
Potential of virtual-social-physical convergence for project manufacturing
Authors: Fox Stephen
Published: October 2014

Purpose

– The purpose of this paper is to provide an analysis of how virtual-social-physical (VSP) convergence can affect different types of project manufacturing. In particular, VSP convergence that involves combining the read-write functionality of Web 2.0 and related social media together with digital tools for virtual design and for physical manufacturing.

Design/methodology/approach

– Literature review and interviews with experts in technologies covering VSP convergence: digital data capture, photogrammetry, generative computation, Web 2.0 and social media, digitally driven manufacturing.

Findings

– VSP convergence can enable the replacement of slow and expensive traditional project manufacturing practices with much faster and less expensive digitally driven technologies.

Practical implications

– There are new opportunities for expansion of some types of project manufacturing. Notably, there are opportunities in non-industrial developing countries because VSP convergence reduces reliance on industrial infrastructure for the manufacturing of goods. By contrast, opportunities may be limited for expansion of established project manufacturing companies with exclusive brands.

Originality/value

– The originality is that VSP convergence is related to different types of project manufacturing. Based on VSP convergence, traditional types and new types of project manufacturing are categorized together for the first time. The value of this paper is that it is explained how VSP convergence can address barriers to expansion of different types of project manufacturing.
External technology acquisition of SMEs in the engineering industry of Bangalore
Authors: Bala Subrahmanya M.H.
Published: October 2014

Purpose

– The purpose of this paper is to ascertain: first, India's public policy support for small and medium enterprises (SMEs) for external technology acquisition (ETA); second, objectives of SMEs for ETA; and third, factors which induced them to obtain their first ETA.

Design/methodology/approach

– Public policy is examined through survey of literature, whereas objectives and factors influencing first ETAs by SMEs are analyzed based on primary data collected from 64 SMEs in Bangalore. Objectives of ETAs are analyzed descriptively whereas factors which facilitated/hindered early ETAs are examined through Cox regression analysis.

Findings

– Public policy for ETAs by SMEs includes technology information, assistance and fiscal incentives. The technology focus of these SMEs has been shifting from conventional lathes to computer numerical control (CNC) machines. Most of the SMEs have gone for technology up-gradation with the objective of improving product quality, scale expansion, and meeting customer demand. Majority of these SMEs have obtained their first ETA within six years of their inception. Firm level factors have significantly influenced the time taken by these SMEs for their first ETAs. Overall, when technology is well developed and easily accessible, SMEs would hardly look for external support for ETAs.

Research limitations/implications

– The shifting technology focus from conventional lathes to CNC machines is a welcome development, which is driven by the need for “competitiveness enhancement”. Since there is no major obstacle for ETAs, policy makers may focus more on providing SMEs with market information and market developments.

Practical implications

– The shifting technology focus from conventional lathes to CNC machines in Indian SMEs is a welcome development, which is largely driven by the need for better product quality, scale expansion and customer demand, and internal factors played a crucial role in the time taken by these SMEs in accomplishing their first ETA. As such there is no major obstacle for these SMEs in going for ETAs since technology suppliers are available at the door-step and finance is available from the banks. Therefore, policy makers may focus more on providing SMEs with market information and market developments in the domestic as well as international market.

Originality/value

– This is a first attempt to examine public policy, objectives and factors influencing SMEs for ETAs in India, after 1991.