bluuebunny/crossref_metadata_2025 huggingface dataset:
Characteristic analysis for integrable soliton models on two-dimensional target spaces
Authors: Goulart E.
Published: November 2015

We investigate the evolutionary aspects of some integrable soliton models whose Lagrangians are derived from the pullback of a volume-form to a two-dimensional target space. These models are known to have infinitely many conserved quantities and support various types of exact analytic solutions with nontrivial topology. In particular, we show that, in spite of the fact that they admit nice smooth solutions, wave propagation about these solutions will always be ill-posed. This is related to the fact that the corresponding Euler-Lagrange equations are not of hyperbolic type.
Lorentz factor determination for local electric fields in semiconductor devices utilizing hyper-thin dielectrics
Authors: McPherson J. W.
Published: November 2015

The local electric field (the field that distorts, polarizes, and weakens polar molecular bonds in dielectrics) has been investigated for hyper-thin dielectrics. Hyper-thin dielectrics are currently required for advanced semiconductor devices. In the work presented, it is shown that the common practice of using a Lorentz factor of L = 1/3, to describe the local electric field in a dielectric layer, remains valid for hyper-thin dielectrics. However, at the very edge of device structures, a rise in the macroscopic/Maxwell electric field Ediel occurs and this causes a sharp rise in the effective Lorentz factor Leff. At capacitor and transistor edges, Leff is found to increase to a value 2/3 < Leff < 1. The increase in Leff results in a local electric field, at device edge, that is 50%–100% greater than in the bulk of the dielectric. This increase in local electric field serves to weaken polar bonds thus making them more susceptible to breakage by standard Boltzmann and/or current-driven processes. This has important time-dependent dielectric breakdown (TDDB) implications for all electronic devices utilizing polar materials, including GaN devices that suffer from device-edge TDDB.
Tables of equation-of-state, thermodynamic properties, and shock Hugoniot for hot dense fluid deuterium
Authors: Zaghloul Mofreh R.
Published: November 2015

We present computational results and tables of the equation-of-state, thermodynamic properties, and shock Hugoniot for hot dense fluid deuterium. The present results are generated using a recently developed chemical model that takes into account different high density effects such as Coulomb interactions among charged particles, partial degeneracy, and intensive short range hard core repulsion. Internal partition functions are evaluated in a statistical-mechanically consistent way implementing recent developments in the literature. The shock Hugoniot curve derived from the present tables is overall in reasonable agreement with the Hugoniot derived from the Nova-laser shock wave experiments on liquid deuterium, showing that deuterium has a significantly higher compressibility than predicted by the SESAME tables or by Path Integral Monte Carlo calculations. Computational results are presented as surface plots for the dissociated fraction, degree of ionization, pressure, and specific internal energy for densities ranging from 0.0001 to 40 g/cm3 and temperatures from 2000 to ∼106 K. Tables for values of the above mentioned quantities in addition to the specific heat at constant pressure, cp, ratio of specific heats, cp/cv, sound speed and Hugoniot curve (for a specific initial state) are presented for practical use.
Characterisation of the current switch mechanism in two-stage wire array Z-pinches
Authors: Burdiak G. C. , Lebedev S. V. , Harvey-Thompson A. J. , Hall G. N. , Swadling G. F. , Suzuki-Vidal F. , Khoory E. , Bland S. N. , Pickworth L. , de Grouchy P. , Skidmore J. , Suttle L. , Waisman E. M.
Published: November 2015

In this paper, we describe the operation of a two-stage wire array z-pinch driven by the 1.4 MA, 240 ns rise-time Magpie pulsed-power device at Imperial College London. In this setup, an inverse wire array acts as a fast current switch, delivering a current pre-pulse into a cylindrical load wire array, before rapidly switching the majority of the generator current into the load after a 100–150 ns dwell time. A detailed analysis of the evolution of the load array during the pre-pulse is presented. Measurements of the load resistivity and energy deposition suggest significant bulk heating of the array mass occurs. The ∼5 kA pre-pulse delivers ∼0.8 J of energy to the load, leaving it in a mixed, predominantly liquid-vapour state. The main current switch occurs as the inverse array begins to explode and plasma expands into the load region. Electrical and imaging diagnostics indicate that the main current switch may evolve in part as a plasma flow switch, driven by the expansion of a magnetic cavity and plasma bubble along the length of the load array. Analysis of implosion trajectories suggests that approximately 1 MA switches into the load in 100 ns, corresponding to a doubling of the generator dI/dt. Potential scaling of the device to higher current machines is discussed.
Re-appraisal and extension of the Gratton-Vargas two-dimensional analytical snowplow model of plasma focus. II. Looking at the singularity
Authors: Auluck S. K. H.
Published: November 2015

The Gratton-Vargas snowplow model, recently revisited and expanded [S. K. H. Auluck, Phys. Plasmas 20, 112501 (2013)], has given rise to significant new insights into some aspects of the Dense Plasma Focus (DPF), in spite of being a purely kinematic description having no reference to plasma phenomena. It is able to provide a good fit to the experimental current waveforms in at least 4 large facilities. It has been used for construction of a local curvilinear frame of reference, in which conservation laws for mass, momentum, and energy can be reduced to effectively-one-dimensional hyperbolic conservation law equations. Its utility in global parameter optimization of device parameters has been demonstrated. These features suggest that the Gratton-Vargas model deserves a closer look at its supposed limitations near the singular phase of the DPF. This paper presents a discussion of its development near the device axis, based on the original work of Gratton and Vargas, with some differences. It is shown that the Gratton-Vargas partial differential equation has solutions for times after the current singularity, which exhibit an expanding bounded volume (which can serve as model of an expanding plasma column) and decreasing dynamic inductance of the discharge, in spite of having no built-in hydrodynamics. This enables the model to qualitatively reproduce the characteristic shape of the current derivative in DPF experiments without reference to any plasma phenomena, such as instabilities, anomalous resistance, or reflection of hydrodynamic shock wave from the axis. The axial propagation of the solution exhibits a power-law dependence on the dimensionless time starting from the time of singularity, which is similar to the power-law relations predicted by theory of point explosions in ideal gases and which has also been observed experimentally.
Effects of three-body collisions in a two-mode Bose-Einstein condensate
Authors: Sabín Carlos , Barberis-Blostein Pablo , Hernández Cristopher , Mann Robert B. , Fuentes Ivette
Published: November 2015

We study the effects of three-body collisions in the physical properties of a two-mode Bose-Einstein condensate. The model introduced here includes two-body and three-body elastic and mode-exchange collisions and can be solved analytically. We will use this fact to show that three-body interactions can produce drastic changes in the probability distribution of the ground state and the dynamics of the relative population. In particular, we find that three-body interactions under certain circumstances may inhibit the collapse of the relative population.
Pull-in analysis of non-uniform microcantilever beams under large deflection
Authors: Singh Sajal Sagar , Pal Prem , Pandey Ashok Kumar
Published: November 2015

Cantilever beams under the influence of electrostatic force form an important subclass of microelectromechanical system (MEMS) and nanoelectromechanical system. Most of the studies concerning these micro-nano resonators are centered around uniform cantilever beams. In this paper, we have investigated another class of micro-resonators consisting of non-uniform cantilever beams. The study is focused around investigating pull-in voltage and resonance frequency of non-uniform cantilever beams when they operate in the linear regime about different static equilibriums. In this paper, we term this frequency as “linear frequency.” Calculation of the linear frequency is done at different static equilibriums corresponding to different DC voltages. We have studied two classes of beams, one with increasing cross sectional area from the clamped edge (diverging beam) and other with decreasing cross sectional area from the clamped edge (converging beam). Within each class, we have investigated beams with linear as well as quartic variation in width. We start by obtaining Euler beam equation for non-uniform cantilever beams considering large deflection and their corresponding exact mode shapes from the linear equation. Subsequently, using the Galerkin method based on single mode approximation, we obtain static and dynamic modal equations for finding pull-in voltage and resonance frequency as a function of DC voltage, respectively. We found that the linear frequency of converging beams increases with increase in non-uniform parameter (α) while those of diverging beams decreases with α. A similar trend is observed for pull-in voltage. Within the converging class, beams with quartic variation in width show significant increase in both frequency and pull-in voltage as compared to corresponding linearly tapered beams. In quantitative terms, converging beams with quartic variation in width and α=−0.6 showed an increase in linear frequency by a factor of 2.5 times and pull-in voltage by 2 times as compared to commonly used uniform beams. Our investigation can prove to be a step forward in designing highly sensitive MEMS sensors and actuators.
Measuring the proton selectivity of graphene membranes
Authors: Walker Michael I. , Braeuninger-Weimer Philipp , Weatherup Robert S. , Hofmann Stephan , Keyser Ulrich F.
Published: November 2015

By systematically studying the proton selectivity of free-standing graphene membranes in aqueous solutions, we demonstrate that protons are transported by passing through defects. We study the current-voltage characteristics of single-layer graphene grown by chemical vapour deposition (CVD) when a concentration gradient of HCl exists across it. Our measurements can unambiguously determine that H+ ions are responsible for the selective part of the ionic current. By comparing the observed reversal potentials with positive and negative controls, we demonstrate that the as-grown graphene is only weakly selective for protons. We use atomic layer deposition to block most of the defects in our CVD graphene. Our results show that a reduction in defect size decreases the ionic current but increases proton selectivity.
Critical current density and microstructure of iron sheathed multifilamentary Sr1−xKxFe2As2/Ag composite conductors
Authors: Yao Chao , Lin He , Zhang Qianjun , Zhang Xianping , Wang Dongliang , Dong Chiheng , Ma Yanwei , Awaji Satoshi , Watanabe Kazuo
Published: November 2015

Iron-based superconductors have been considered to be very promising in high-field applications for which multifilamentary wire and tape conductors with high mechanical strength are essential. In this work, 7-,19-, and 114-filament Sr0.6K0.4Fe2As2 (Sr-122) superconducting wires and tapes with silver as matrix and iron as outer reinforcing sheath were produced by the ex situ powder-in-tube method. The mass densities of Sr-122 phase in 7- and 19-filament conductors were investigated by microhardness characterization, which revealed a positive correlation between hardness and transport critical current density (Jc) in round wires and flat tapes with various thicknesses. For Sr-122/Ag/Fe 114-filament conductors, in which an average cross-sectional filament size smaller than 50 μm was achieved by drawing into round wires of 2.0 mm in diameter, the transport Jc can be significantly enhanced by flat rolling, as for the 7- and 19-filament conductors. The highest transport Jc for Sr-122 filaments in the 7-, 19-, and 114-filament Sr-122/Ag/Fe tapes reached 1.4 × 104, 8.4 × 103, and 6.3 × 103 A cm−2 (4.2 K, 10 T), respectively, showing a Jc degradation with the increase of filament number. This Jc degradation can be ascribed to the sausage effect for SR-122 filaments in longitudinal direction and the grain refinement in these very fine filaments.
In situ study of the endotaxial growth of hexagonal CoSi2 nanoplatelets in Si(001)
Authors: da Silva Costa Daniel , Huck-Iriart Cristián , Kellermann Guinther , Giovanetti Lisandro J. , Craievich Aldo F. , Requejo Félix G.
Published: November 2015

This investigation aims at studying–by in situ grazing-incidence small-angle x-ray scattering–the process of growth of hexagonal CoSi2 nanoplatelets endotaxially buried in a Si(001) wafer. The early formation of spherical Co nanoparticles with bimodal size distribution in the deposited silica thin film during a pretreatment at 500 °C and their subsequent growth at 700 °C were also characterized. Isothermal annealing at 700 °C promotes a drastic reduction in the number of the smallest Co nanoparticles and a continuous decrease in their volume fraction in the silica thin film. At the same time, Co atoms diffuse across the SiO2/Si(001) interface into the silicon wafer, react with Si, and build up thin hexagonal CoSi2 nanoplatelets, all of them with their main surfaces parallel to Si{111} crystallographic planes. The observed progressive growths in thickness and lateral size of the hexagonal CoSi2 nanoplatelets occur at the expense of the dissolution of the small Co nanoparticles that are formed during the pretreatment at 500 °C and become unstable at the annealing temperature (700 °C). The kinetics of growth of the volume fraction of hexagonal platelets is well described by the classical Avrami equation.
Control of multiple excited image states around segmented carbon nanotubes
Authors: Knörzer J. , Fey C. , Sadeghpour H. R. , Schmelcher P.
Published: November 2015

Electronic image states around segmented carbon nanotubes can be confined and shaped along the nanotube axis by engineering the image potential. We show how several such image states can be prepared simultaneously along the same nanotube. The inter-electronic distance can be controlled a priori by engineering tubes of specific geometries. High sensitivity to external electric and magnetic fields can be exploited to manipulate these states and their mutual long-range interactions. These building blocks provide access to a new kind of tailored interacting quantum systems.
Polarization-dependent diffraction in all-dielectric, twisted-band structures
Authors: Kardaś Tomasz M. , Jagodnicka Anna , Wasylczyk Piotr
Published: November 2015

We propose a concept for light polarization management: polarization-dependent diffraction in all-dielectric microstructures. Numerical simulations of light propagation show that with an appropriately configured array of twisted bands, such structures may exhibit zero birefringence and at the same time diffract two circular polarizations with different efficiencies. Non-birefringent structures as thin as 3 μm have a significant difference in diffraction efficiency for left- and right-hand circular polarizations. We identify the structural parameters of such twisted-band matrices for optimum performance as circular polarizers.
Near-field enhanced optical tweezers utilizing femtosecond-laser nanostructured substrates
Authors: Kotsifaki D. G. , Kandyla M. , Lagoudakis P. G.
Published: November 2015

We present experimental evidence of plasmonic-enhanced optical tweezers, of polystyrene beads in deionized water in the vicinity of metal-coated nanostructures. The optical tweezers operate with a continuous wave near-infrared laser. We employ a Cu/Au bilayer that significantly improves dissipation of heat generated by the trapping laser beam and avoid de-trapping from heat convection currents. We investigate the improvement of the optical trapping force and the effective trapping quality factor, and observe an exponential distance dependence of the trapping force from the nanostructures, indicative of evanescent plasmonic enhancement.
Multi-directional energy harvesting by piezoelectric cantilever-pendulum with internal resonance
Authors: Xu J. , Tang J.
Published: November 2015

This letter reports a piezoelectric cantilever-pendulum design for multi-directional energy harvesting. A pendulum is attached to the tip of a piezoelectric cantilever-type energy harvester. This design aims at taking advantage of the nonlinear coupling between the pendulum motion in 3-dimensional space and the beam bending vibration at resonances. Experimental studies indicate that, under properly chosen parameters, 1:2 internal resonance can be induced, which enables the multi-directional energy harvesting with a single cantilever. The advantages of the design with respect to traditional piezoelectric cantilever are examined.
Mid-infrared metamorphic interband cascade photodetectors on GaAs substrates
Authors: Tian Zhao-Bing , Krishna Sanjay
Published: November 2015

Antimony-based mid-infrared interband cascade (IC) photodetectors fabricated on (001) GaAs substrates are reported. By using a “buffer-free” interfacial misfit array growth method, an overall good crystalline quality is obtained on the largely lattice-mismatched GaAs substrate. The GaAs-based IC detectors show comparable optical performance, with similar electrical performance at temperatures higher than 140 K, as compared to the reference devices grown on GaSb substrate. The GaAs-based IC detectors demonstrate dark current density of 2.63 × 10−6 A/cm2 at 180 K, which is about twice as compared to that grown on GaSb substrate, with Johnson-limited D* of 1.06 × 1011 Jones at 180 K and 4.0 μm. The results indicate that IC detector design is robust and relatively insensitive to the material quality, and metamorphic IC detector is viable for large-format infrared focal plane array applications.
Mn doped InSb studied at the atomic scale by cross-sectional scanning tunneling microscopy
Authors: Mauger S. J. C. , Bocquel J. , Koenraad P. M. , Feeser C. E. , Parashar N. D. , Wessels B. W.
Published: November 2015

We present an atomically resolved study of metal-organic vapor epitaxy grown Mn doped InSb. Both topographic and spectroscopic measurements have been performed by cross-sectional scanning tunneling microscopy (STM). The measurements on the Mn doped InSb samples show a perfect crystal structure without any precipitates and reveal that Mn acts as a shallow acceptor. The Mn concentration of the order of ∼1020 cm−3 obtained from the cross-sectional STM data compare well with the intended doping concentration. While the pair correlation function of the Mn atoms showed that their local distribution is uncorrelated beyond the STM resolution for observing individual dopants, disorder in the Mn ion location giving rise to percolation pathways is clearly noted. The amount of clustering that we see is thus as expected for a fully randomly disordered distribution of the Mn atoms and no enhanced clustering or second phase material was observed.
Identification of nitrogen acceptor in Cu2O: First-principles study
Authors: T-Thienprasert Jiraroj , Limpijumnong Sukit
Published: November 2015

The source of p-type carriers observed in nitrogen-doped Cu2O samples [Appl. Phys. Lett. 82, 1060 (2003)] was identified by using accurate hybrid density functional calculations. Similar to the case of ZnO, we found that N is a deep acceptor when substituting for O in Cu2O and cannot be the source of the observed p-type carriers. Detailed investigation of other N-related defects in Cu2O reveals that N2 substitution for Cu, i.e., (N2)Cu, is a shallow acceptor and can give hole carriers in N-doped Cu2O samples. (N2)Cu is not only a shallow acceptor but it also has a lower formation energy than NO in some growth conditions. The calculated emission photo luminescence (PL) peak at 1.89 eV associated with (N2)Cu is also in good agreement with the observed N-related PL peak at ∼1.82 eV in N-doped Cu2O sample. To aid future identification by Raman spectroscopy techniques, the vibrational frequencies of N2 on both Cu and O sites were calculated.
Cr-doped Ge2Sb2Te5 for ultra-long data retention phase change memory
Authors: Wang Qing , Liu Bo , Xia Yangyang , Zheng Yonghui , Huo Ruru , Zhang Qi , Song Sannian , Cheng Yan , Song Zhitang , Feng Songlin
Published: November 2015

Phase change memory is regarded as one of the most promising candidates for the next-generation non-volatile memory. Its storage medium, phase change material, has attracted continuous exploration. Ge2Sb2Te5 (GST) is the most popular phase change material, but its thermal stability needs to be improved when used in some fields at high temperature (more than 120 °C). In this paper, we doped Cr atoms into GST and obtained Cr10(Ge2Sb2Te5)90 (labeled as Cr-GST) with high thermal stability. For Cr-GST film, the sheet resistance ratio between amorphous and crystalline states is high up to 3 orders of magnitude. The crystalline Cr-GST film inherits the phase structure of GST, with metastable face-centered cubic phase and/or stable hexagonal phase. The doped Cr atoms not only bond with other atoms but also help to improve the anti-oxidation property of Cr-GST. As for the amorphous thermal stability, the calculated temperature for 10-year-data-retention of Cr-GST film, based on the Arrhenius equation, is about 180 °C. The threshold current and threshold voltage of a cell based on Cr-GST are about 6 μA and 2.7 V. The cell could be operated by suitable voltages for more than 40 000 cycles. Thus, Cr-GST is proved to be a promising phase change material with ultra-long data retention.
Study of flow rate induced measurement error in flow-through nano-hole plasmonic sensor
Authors: Tu Long , Huang Liang , Wang Tianyi , Wang Wenhui
Published: November 2015

Flow-through gold film perforated with periodically arrayed sub-wavelength nano-holes can cause extraordinary optical transmission (EOT), which has recently emerged as a label-free surface plasmon resonance sensor in biochemical detection by measuring the transmission spectral shift. This paper describes a systematic study of the effect of microfluidic field on the spectrum of EOT associated with the porous gold film. To detect biochemical molecules, the sub-micron-thick film is free-standing in a microfluidic field and thus subject to hydrodynamic deformation. The film deformation alone may cause spectral shift as measurement error, which is coupled with the spectral shift as real signal associated with the molecules. However, this microfluid-induced measurement error has long been overlooked in the field and needs to be identified in order to improve the measurement accuracy. Therefore, we have conducted simulation and analytic analysis to investigate how the microfluidic flow rate affects the EOT spectrum and verified the effect through experiment with a sandwiched device combining Au/Cr/Si3N4 nano-hole film and polydimethylsiloxane microchannels. We found significant spectral blue shift associated with even small flow rates, for example, 12.60 nm for 4.2 μl/min. This measurement error corresponds to 90 times the optical resolution of the current state-of-the-art commercially available spectrometer or 8400 times the limit of detection. This really severe measurement error suggests that we should pay attention to the microfluidic parameter setting for EOT-based flow-through nano-hole sensors and adopt right scheme to improve the measurement accuracy.
DNA polymerases δ and λ cooperate in repairing double-strand breaks by microhomology-mediated end-joining in
Saccharomyces cerevisiae
Authors: Meyer Damon , Fu Becky Xu Hua , Heyer Wolf-Dietrich
Published: November 2015

Significance

The human genome contains many segments of short repetitive DNA, known as microhomologies, which are potential sites for the types of rearrangements found in many different types of cancer. Therefore, understanding how microhomologies within DNA can initiate chromosome rearrangements and the genes involved in promoting this process is critical in understanding cancer development. We examined the repair efficiency of DNA containing microhomologies and found a positive correlation between microhomology length and quality with repair efficiency. Furthermore, our work directly implicates the major DNA replication and repair polymerase, DNA polymerase δ, in repair of DNA damage using microhomologies, which act in conjunction with DNA polymerase λ. Our data suggest a two-polymerase model for microhomology-mediated end-joining.
Influence of Circle Hook Size on Catch Rate and Size of Red Grouper in Shallow Waters of the Southern Gulf of Mexico
Authors: Brulé Thierry , Montero-Muñoz Jorge , Morales-López Natalia , Mena-Loria Andy
Published: November 2015

High rates of undersized catch and discard mortality are common in fisheries for Red Grouper Epinephelus morio in the Gulf of Mexico and Atlantic Ocean. Reducing undersized catch rate in these fisheries requires more effective regulation of the minimum size limit (MSL). One potential method is to regulate hook selectivity for target species. Three circle hook sizes (11/0, 12/0, and 13/0) were tested to assess the effect of hook size on Red Grouper catch rate and size in the shallow waters of the Yucatan Peninsula coast, which is the primary fishing zone for the region's small-scale grouper (family Epinephelidae) fishery. Red Grouper was always the numerically dominant species in catches (76–81%) for all hook sizes. Hook size did not affect mean catch rate. Significantly longer fish were caught in the 13/0 hook size treatment than in the 11/0 and 12/0 treatments, which did not differ. Nonetheless, when considering the MSL regulation applicable in Mexico's Red Grouper fishery (36.3 cm TL), high percentages of undersized Red Grouper were still caught, regardless of hook size. The hook sizes required in the Yucatan small-scale fishery (10/0–12/0) provide little if any improvement in Red Grouper MSL regulation. Real improvement would require the effective release of undersized fish as well as a reduction in the number of undersized specimens caught and in potential cryptic sources of fish release mortality (e.g., barometric trauma). Furthermore, the current applicable Red Grouper MSL only really attempts to control growth overfishing and ignores recruitment overfishing.

Received December 22, 2014; accepted September 3, 2015
Comparison of air kerma area product and air kerma meter calibrations for X-ray radiation qualities used in diagnostic radiology
Authors: Hourdakis C J , Csete I , Daures J , Jarvinen H , Mihailescu L-C , Sochor V , Novak L , Pedersen M , Kosunen A , Toroi P , Denoziere M , Büermann L , Megzifene A , Einarsson G , Ferrari P , dePooter J , Bjerke H , Brodecki M , Cardoso J , Bercea S , Ciraj-Bjelac O , Compel J , Glavič-Cindro D , Ginjaume M , Persson L , Grindborg J -E
Published: November 2015

The EURAMET #1177 project, identified as EURAMET RI(I) - S9 comparison, was the first EURAMET wide scale supplementary comparison in the field of diagnostic radiology for air kerma area product, PKA, and air kerma, K. It was conducted with the goal of testing the measurement and calibration capabilities for PKA and K, as well as of supporting the relevant CMCs of the participating laboratories.

Two commercial KAP meters and an ionization chamber were selected as transfer instruments and circulated between the 22 European participants. The measurements were performed from April 2011 until July 2012.

The stability and the performance of the transfer instruments were tested by the pilot laboratory (IRCL/GAEC-EIM) and few other laboratories as well. The test results revealed that the energy (radiation quality), Q, irradiation area, A, and air kerma rate, K̇ dependences of response of the transfer KAP meters influence the comparison of the results when different measurement conditions were pertained and therefore, appropriate correction factors were obtained and applied to the reported calibration results of the laboratories, when necessary.

The comparison reference values (CRVs) for each instrument were determined as the weighted mean of the calibration coefficients of the three participating primary laboratories. The relative standard uncertainty of the CRVs were in the range of (0.4 - 1.6)% depending on the transfer instruments and beam qualities. The comparison result as the ratio of the corrected calibration coefficient of participant and the respective CRV, and its uncertainty were calculated for all beam qualities and transfer instruments. The informative degrees of equivalence (DoE) were calculated for the refrence RQR 5 beam quality. In case of air kema area product measurements the results for the RADCAL PDC KAP meter were used.

The 216 KAP meter calibration results of the two different transfer instruments in terms of air kerma area product were consistent within 5% except 40 results of 8 participants.

The 103 air kerma calibration results were consistent within 1.7%, except 10 results of 4 participants.

Main text

To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.

The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).
Synchronized navigation and comparative analyses across Ensembl complete bacterial genomes with INSYGHT
Authors: Lacroix Thomas , Thérond Sylvie , Rugeri Marc , Nicolas Pierre , Gendrault Annie , Loux Valentin , Gibrat Jean-François
Published: November 2015

Motivation: High-throughput sequencing technologies provide access to an increasing number of bacterial genomes. Today, many analyses involve the comparison of biological properties among many strains of a given species, or among species of a particular genus. Tools that can help the microbiologist with these tasks become increasingly important.

Results: Insyght is a comparative visualization tool whose core features combine a synchronized navigation across genomic data of multiple organisms with a versatile interoperability between complementary views. In this work, we have greatly increased the scope of the Insyght public dataset by including 2688 complete bacterial genomes available in Ensembl thus vastly improving its phylogenetic coverage. We also report the development of a virtual machine that allows users to easily set up and customize their own local Insyght server.

Availability and implementation:  http://genome.jouy.inra.fr/Insyght

Contact:  Thomas.Lacroix@jouy.inra.fr
Photometry of very bright stars with Kepler and K2 smear data
Authors: Pope B. J. S. , White T. R. , Huber D. , Murphy S. J. , Bedding T. R. , Caldwell D. A. , Sarai A. , Aigrain S. , Barclay T.
Published: November 2015

High-precision time series photometry with the Kepler satellite has been crucial to our understanding both of exoplanets, and via asteroseismology, of stellar physics. After the failure of two reaction wheels, the Kepler satellite has been repurposed as Kepler-2 (K2), observing fields close to the ecliptic plane. As these fields contain many more bright stars than the original Kepler field, K2 provides an unprecedented opportunity to study nearby objects amenable to detailed follow-up with ground-based instruments. Due to bandwidth constraints, only a small fraction of pixels can be downloaded, with the result that most bright stars which saturate the detector are not observed. We show that engineering data acquired for photometric calibration, consisting of collateral ‘smear’ measurements, can be used to reconstruct light curves for bright targets not otherwise observable with Kepler/K2. Here we present some examples from Kepler Quarter 6 and K2 Campaign 3, including the δ Scuti variables HD 178875 and 70 Aqr, and the red giant HR 8500 displaying solar-like oscillations. We compare aperture and smear photometry where possible, and also study targets not previously observed. These encouraging results suggest this new method can be applied to most Kepler and K2 fields.
Substantial DNA methylation differences between two major neuronal subtypes in human brain
Authors: Kozlenkov Alexey , Wang Minghui , Roussos Panos , Rudchenko Sergei , Barbu Mihaela , Bibikova Marina , Klotzle Brandy , Dwork Andrew J , Zhang Bin , Hurd Yasmin L , Koonin Eugene V , Wegner Michael , Dracheva Stella
Published: November 2015

The brain is built from a large number of cell types which have been historically classified using location, morphology and molecular markers. Recent research suggests an important role of epigenetics in shaping and maintaining cell identity in the brain. To elucidate the role of DNA methylation in neuronal differentiation, we developed a new protocol for separation of nuclei from the two major populations of human prefrontal cortex neurons—GABAergic interneurons and glutamatergic (GLU) projection neurons. Major differences between the neuronal subtypes were revealed in CpG, non-CpG and hydroxymethylation (hCpG). A dramatically greater number of undermethylated CpG sites in GLU versus GABA neurons were identified. These differences did not directly translate into differences in gene expression and did not stem from the differences in hCpG methylation, as more hCpG methylation was detected in GLU versus GABA neurons. Notably, a comparable number of undermethylated non-CpG sites were identified in GLU and GABA neurons, and non-CpG methylation was a better predictor of subtype-specific gene expression compared to CpG methylation. Regions that are differentially methylated in GABA and GLU neurons were significantly enriched for schizophrenia risk loci. Collectively, our findings suggest that functional differences between neuronal subtypes are linked to their epigenetic specification.
Serum Autotaxin Activity Correlates With Pruritus in Pediatric Cholestatic Disorders
Authors: Kremer Andreas E. , Gonzales Emmanuel , Schaap Frank G. , Oude Elferink Ronald P.J. , Jacquemin Emmanuel , Beuers Ulrich
Published: November 2015

Objective:

Pruritus is a common symptom of cholestatic liver disorders. The present study aimed at evaluating autotaxin (ATX), a lysophospholipase recently identified as potential cause for cholestatic pruritus, in pediatric cholestatic diseases presenting with or without itching.

Methods:

A cohort of 45 children consisting of 14 patients experiencing itching (Alagille syndrome [n = 10], complete extrahepatic biliary atresia [n = 2], neonatal sclerosing cholangitis (n = 1), progressive familial intrahepatic cholestasis type 2 [n = 1]), 9 patients with bile acid synthesis defects (3β‐hydroxy‐C27‐steroid‐oxidoreductase [n = 7] and Δ4–3‐oxosteroid‐5β‐reductase deficiency [n = 2]), and 22 healthy children were studied. Serum ATX activity and total serum bile salt were determined enzymatically, ATX protein content was semiquantified by Western blotting. Using real‐time polymerase chain reaction, ATX mRNA expression was studied in HepG2 cells treated with farnesoid‐X‐receptor agonists or vehicle.

Results:

Serum ATX activity was increased in pruritic children with Alagille and other cholestatic syndromes (mean ± standard deviation: 16.1 ± 4.3 nmol · mL−1 · min−1) compared with children with nonpruritic cholestatic diseases with bile acid synthesis defects (10.4 ± 4.7 nmol · mL−1 · min−1; P < 0.01) and healthy controls (7.6 ± 2.3 nmol · mL−1 · min−1; P < 0.001). ATX protein levels closely correlated with serum ATX activity. Serum ATX activity and total serum bile salt showed a linear correlation with itch intensity (r = 0.66, P < 0.001 and r = 0.80, P < 0.001, respectively). No correlation was observed between ATX activity and bilirubin. ATX mRNA expression in HepG2 cells was not induced by farnesoid‐X‐receptor ligands.

Conclusions:

Serum ATX activity correlated with itch intensity in children with cholestatic diseases. Bile salts did not increase ATX expression in vitro. ATX inhibitors may be useful antipruritic agents in pediatric cholestatic disorders.
Stability of murine scrapie strain 87V after passage in sheep and comparison with the CH1641 ovine strain
Authors: González Lorenzo , Chianini Francesca , Hunter Nora , Hamilton Scott , Gibbard Louise , Martin Stuart , Dagleish Mark P. , Sisó Sílvia , Eaton Samantha L. , Chong Angela , Algar Lynne , Jeffrey Martin
Published: November 2015

Breed- and prion protein (PRNP) genotype-related disease phenotype variability has been observed in sheep infected with the 87V murine scrapie strain. Therefore, the stability of this strain was tested by inoculating sheep-derived 87V brain material back into VM mice. As some sheep-adapted 87V disease phenotypes were reminiscent of CH1641 scrapie, transgenic mice (Tg338) expressing ovine prion protein (PrP) were inoculated with the same sheep-derived 87V sources and with CH1641. Although at first passage in VM mice the sheep-derived 87V sources showed some divergence from the murine 87V control, all the characteristics of murine 87V infection were recovered at second passage from all sheep sources. These included 100 % attack rates and indistinguishable survival times, lesion profiles, immunohistochemical features of disease-associated PrP accumulation in the brain and PrP biochemical properties. All sheep-derived 87V sources, as well as CH1641, were transmitted to Tg338 mice with identical clinical, pathological, immunohistochemical and biochemical features. While this might potentially indicate that sheep-adapted 87V and CH1641 are the same strain, profound divergences were evident, as murine 87V was unable to infect Tg338 mice but was lethal for VM mice, while the reverse was true for CH1641. These combined data suggest that: (i) murine 87V is stable and retains its properties after passage in sheep; (ii) it can be isolated from sheep showing a CH1641-like or a more conventional scrapie phenotype; and (iii) sheep-adapted 87V scrapie, with conventional or CH1641-like phenotype, is biologically distinct from experimental CH1641 scrapie, despite the fact that they behave identically in a single transgenic mouse line.
MocDoc.in: Choreographing online healthcare kingdom
Authors: Puri Roma
Published: November 2015

Subject area

Marketing, Innovation, Strategy, Digital Marketing and E-Business.

Study level/applicability

Master's level and Executive Program.

Case overview

MocDoc is a young Indian online health-care company that has achieved success in early years of establishment, and is looking forward to expand the customer base. The founder, Senthil Peelikkampatti, along with his friends decided to design a service that can bridge the gap between doctor and patients. However, initially, Senthil lost the trust in his idea due to the unacceptance of the idea by health-care experts. It took a little long for the team to gain visibility after launch of the service. Senthil and the team brainstormed to gain recognition online through different techniques of search engine optimization (SEO) and social media networking through Facebook Web site. MocDoc case is designed to stimulate discussion of a broad array of entrepreneurial issues related to online start-ups. In particular, it deals with strategy and marketing of service in the online arena. At the same time, it gives detailed overview of marketing techniques online as fuel to the business. The company is moving under strong leadership skills of CEO but fails to gain momentum in terms of gaining online customers. This case deals with decision-making capabilities to bring more number of registered customers in the online space.

Expected learning outcomes

The expected learning outcomes are as follows: to animate online business environment and challenges faced by virtual enterprises in the cyber space; to illustrate opportunity for students to speculate the start-up business environment; to illustrate opportunity to introduce cloud computing as a viable business option for the health-care industry; to develop understanding among students for designing effective marketing strategy for online business; to identify business opportunities and gaining competitive edge by offering bouquet of services; and to stimulate business environment for understanding innovation and strategy building.

Supplementary materials

Teaching Notes are available for educators only. Please contact your library to gain login details or email support@emeraldinsight.com to request teaching notes.
Unforeseen bumps on the road of entrepreneurship
Authors: Sharma Tanushree , Grover Priya
Published: November 2015

Subject area

The case throws light on the unforeseen challenges new entrepreneurs confront. It highlights how the challenges of manpower, sales and operations are intertwined. It also put emphasis on holistic planning prior to initiating a business.

Study level/applicability

This case can be used in the introductory courses on entrepreneurship and sales and distribution for undergraduate and postgraduate students of Business Schools.

Case overview

This case revolves around the pursuit of an entrepreneur to develop and service sweetcorn vending kiosks in an Indian State. It narrates the dilemma faced by the entrepreneur when she discovered a notional loss of revenue as a result of her selecting a particular distribution channel. The entrepreneur realized that the entire range of products sold through the dealer was fetching her far less revenue in comparison to the only product she retailed herself. She also realized that the retail though paid better dividends, but also brought along host of manpower and operative issues. With the day of signing a firm contract with the dealer coming close, the entrepreneur must decide quickly her future course of action.

Expected learning outcomes

The students will be able to gain understanding of the unforeseen challenges confronted by small entrepreneurs, interconnection of various functions of business and the significance of holistic planning.

Supplementary materials

Teaching Notes are available for educators only. Please contact your library to gain login details or email support@emeraldinsight.com to request teaching notes.
Financing universities throughwaqf, pious endowment: is it possible?
Authors: Mahamood Siti Mashitoh , Ab Rahman Asmak
Published: November 2015

Purpose

– The purpose of this article is to highlight the importance of waqf in financing higher education. Nowadays, higher education is costly and this has prevented students, especially those who are self-financed, from accessing such learning environments. This paper offer an alternative solution to relieve such a situation, namely, through the application of an endowment-based orwaqfeducational institution. The study suggests a way to establish an endowment university by concentrating the discussion on the concept and principles of its establishment, as well as sharing the experiences of the Malaysianwaqfuniversities and the Turkish Foundation Universities/Vakif Üniversitesi in financing their universities usingwaqf, i.e. a pious endowment instrument.

Design/methodology/approach

– The empirical data were mainly collected using in-depth interviews with the universities’ higher management authorities and some of the members of the board of trustees.

Findings

– The findings show that the role ofwaqfor pious endowment is significant in providing financial assistance to their communities as well as strengthening their academic quality. In addition, tawhidic epistemology together with morality and ethics have influencedwaqfdonors or founders to donate their wealth and property to enrich and sustain universities and higher education.

Originality/value

– This article provides the experiences of the MalaysianWaqfUniversities and the Turkish Foundation Universities/Vakif Üniversitesi in financing their universities usingwaqf. It also contains some good examples from the experience of several earlier Islamic civilizations, in particular those of the Ottoman Empire and the Mamluk Sultanate of Egypt. In addition, examples of the implementation ofwaqfand endowment-based universities in the UK and USA as well as the Al-Azhar University of Egypt is also included.
The development of an evaluation framework for a Hospital at Home service
Authors: Jester Rebecca , Titchener Karen , Doyle-Blunden Janet , Caldwell Christine
Published: November 2015

Purpose

– The purpose of this paper is to share good practice with interested professionals, commissioners and health service managers regarding the development of an evidence-based approach to evaluation of an integrated care service providing acute level care for patients in their own homes in South London called the Guys and St Thomas’ @home service.

Design/methodology/approach

– A literature review related to Hospital at Home (HH) schemes was carried out with an aim of scoping approaches used during previous evaluations of HH type interventions to inform the development of an evaluation strategy for @home. The results of the review were then applied to the Donabedian conceptual model: Structure; Process; and Outcome and contextualised to the population being served by the scheme to ensure a robust, practical and comprehensive approach to evaluation.

Findings

– Due to the heterogeneity of the studies it was not possible to conduct a systematic review or meta-analysis. In total, 28 studies were identified that met the inclusion criteria and included both HH to facilitate early discharge and admission prevention across a wide range of conditions. The key finding was there is a dearth of literature evaluating staff preparation to work on HH, models of delivery, specifically integrated care and trans-disciplinary working and few studies included the experiences of family carers.

Originality/value

– This paper will be of value to those involved in the commissioning and delivery of HH and other models of integrated care services type services and will help to inform evaluation strategies that are practical, evidence based and include all stakeholder perspectives.
The local effect of octreotide on mechanical pain sensitivity is more sensitive in DA rats than DA.1U rats
Authors: Yao Fan‐Rong , Wang Hui‐Sheng , Guo Yuan , Zhao Yan
Published: November 2015

A recent study by the authors indicated that major histocompatibility complex (MHC) genes are associated with the differences in basal pain sensitivity and in formalin model between Dark‐Agouti (DA) and novel congenic DA.1U rats, which have the same genetic background as DA rats except for the u alleles of MHC. The objective of the present study is to investigate whether there is a difference in the pristane‐induced arthritis (PIA) model and local analgesic effect of octreotide (OCT) between DA and DA.1U rats. The hindpaw mechanical withdrawal threshold (MWT) and heat withdrawal latency (HWL) were observed. The C unit firings of the tibial nerve evoked by non‐noxious and noxious toe movements were recorded by electrophysiological methods in normal and PIA models in DA and DA.1U rats before and after local OCT administration. The expression of somatostatin receptor 2A (SSTR2A) was observed by immunohistochemistry. The results demonstrate that DA rats have a higher mechanical sensitivity than DA.1U rats after PIA. Local OCT administration significantly elevated MWT in DA rats under normal and PIA sate, but not in DA.1U rats. The electrophysiological experiments showed OCT significantly attenuated the firings of C units evoked by non‐noxious and noxious stimulation in DA rats more than those in DA.1U rats both in normal and PIA states. In addition, the expression of SSTR2A in the dorsal horn of the spinal cord was significantly higher in DA than in DA.1U rats. All of the findings suggest a higher local analgesic effect of OCT in DA rats than DA.1U rats, which might be associated with the MHC genes.