bluuebunny/crossref_metadata_2025 huggingface dataset:
Développement dramaturgique et perspective systémique de la créativité à La Troupe du Jour de Saskatoon
Authors: Théberge Mariette
Published: February 2013

Cet article vise à comprendre la manière dont le développement dramaturgique de La Troupe du Jour de Saskatoon est mis en oeuvre et s’inscrit dans une perspective systémique de la créativité. À cette fin, les concepts d’expérience et d’accompagnement, la théorie de l’apprentissage transformationnel ainsi que le modèle de la perspective systémique de l’étude de la créativité constituent les assises du cadre conceptuel de la présente recherche qui se situe dans un contexte d’apprentissage non pas pas scolaire, mais institutionnel. Il s’agit d’une recherche qualitative, plus spécifiquement d’une étude de cas dont la principale stratégie de collecte de données est l’entrevue individuelle semi-dirigée réalisée auprès de neuf participants, dont deux conseillers dramaturgiques, cinq dramaturges ainsi que les directeurs artistique et administratif de La Troupe du Jour. Les résultats de l’analyse de ces témoignages mettent en valeur les temps d’émergence, de consolidation et de reconnaissance de cette dramaturgie en plaçant l’expérience et l’accompagnement comme clef de voûte de la pratique de développement dramaturgique dans ce contexte.
Development of Residual Stresses and Texture in Drawn Copper Tubes
Authors: Carradò Adele , Brokmeier Heinz‐Guenter , Pirling Thilo , Wimpory Robert Charles , Schell Norbert , Palkowski Heinz
Published: February 2013

The residual stress state and the texture in Cu‐tubes, drawn without a plug under controlled laboratory conditions, are presented. Neutron stress determination confirms a stress gradient from the outer to the inner surface of the tube walls. High energy X‐rays were used to analyze the texture gradient around the perimeter of the tubes as well as over the wall thickness. Anisotropic flow during tube processing results in texture variations described by ODF‐analysis.
Molecular design and stabilization mechanism of acrylonitrile bipolymer
Authors: Ju Anqi , Guang Shanyi , Xu Hongyao
Published: February 2013

In order to replace terpolymer with bipolymer, a bifunctional comonomer 3‐aminocarbonyl‐3‐butenoic acid methyl ester (ABM) was synthesized for preparing poly(acrylonitrile‐co‐3‐aminocarbonyl‐3‐butenoic acid methyl ester) [P(AN‐co‐ABM)] bipolymers as carbon fiber precursor. The structure and stabilization of P(AN‐co‐ABM) bipolymers were characterized by Fourier transform infrared spectroscopy, X‐ray diffraction, and differential scanning calorimetry. The monomer reactivity ratios were calculated by the Fineman‐Ross and Kelen‐Tüdõs methods, and the results show that ABM displays higher reactivity than acrylonitrile. Two parameters Es = A1618cm‐1/A2244cm‐1 and SI = (I0 ‐ Is)/I0 were defined to evaluate the extent of stabilization, and the activation energy (Ea) of the stabilization reactions were calculated by Kissinger and Ozawa methods. The results show that the P(AN‐co‐ABM) bipolymers exhibit significantly improved stabilization performance when compared with polyacrylonitrile (PAN) homopolymer, such as lower cyclization temperature, lower Ea, and larger extent of stabilization under the same conditions. Simultaneously, the rheological analysis shows that P(AN‐co‐ABM) possesses better spinnability than PAN. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Readily Accessible Fluorescent Probes for Sensitive Biological Imaging of Hydrogen Peroxide
Authors: Daniel Kevin B. , Agrawal Arpita , Manchester Marianne , Cohen Seth M.
Published: February 2013

Hydrogen peroxide is a major component of oxygen metabolism in biological systems that, when present in high concentrations, can lead to oxidative stress in cells. Noninvasive molecular imaging of H2O2 using fluorogenic systems represents an effective way to detect and measure the accumulation of this metabolite. Herein, we detail the development of robust H2O2‐sensitive fluorescent probes using a boronic ester trigger appended to the fluorophore through a benzyl ether linkage. A major advantage of the probes presented here is their synthetic accessibility, with only one step needed to generate the probes on the gram scale. The sensitivity of the probes was evaluated in simulated physiological conditions, showing micromolar sensitivity to H2O2. The probes were tested in biological model systems, demonstrating effective imaging of unstimulated, endogenous H2O2 levels in RAW 264.7 cells and murine brain tissue.
Solving matrix effect, spectral overlapping and nonlinearity by generalized standard addition method coupled with radial basis functions–partial least squares: simultaneous determination of atorvastatin and amlodipine in urine
Authors: Shariati‐Rad Masoud , Irandoust Mohsen , Amini Tayyebeh , Shamsipur Mojtaba
Published: February 2013

For simultaneous determination in conditions with spectral overlap and variation of matrix effects, coupling of the generalized standard addition method (GSAM) with the multivariate nonlinear method of radial basis function–partial least squares (RBF–PLS) was proposed. The nonlinearity caused by the GSAM used to correct matrix effects was studied, and principal component analysis was proposed for identifying it. In the method introduced, the whole sensor range can be used without the collinearity problem encountered in the application of GSAM with classical least squares (CLS), and calibration can be made for each analyte, separately. The introduced method was applied to determine amlodipine and atorvastatin in urine samples. The mean of the percent recoveries was between 95 and 101.12. The percent relative standard deviation values of the method were in most cases below 5%. The results of GSAM–RBF–PLS were compared with those obtained by GSAM–CLS and GSAM–PLS. Copyright © 2013 John Wiley & Sons, Ltd.
Pharmacokinetics and Safety of Migalastat HCl and Effects on Agalsidase Activity in Healthy Volunteers
Authors: Johnson Franklin K. , Mudd Paul N. , Bragat Alexander , Adera Mathews , Boudes Pol
Published: February 2013

Migalastat HCl is an investigational, oral treatment for Fabry disease, an X‐linked lysosomal storage disorder. Four Phase 1 studies were conducted to determine the pharmacokinetics, pharmacodynamics, safety, and tolerability of migalastat. Healthy volunteers (N = 124), 18–55 years old, received migalastat HCl single (25 mg–2000 mg) or twice‐daily doses (50 mg, 150 mg) for 7 days in a double‐blind, placebo‐controlled fashion. Migalastat pharmacokinetics were dose‐proportional (AUC∞ range: 1129–72 838 ng h/mL, Cmax range: 200.5–13 844 ng/mL, t1/2 3–4 hours). Steady state was achieved by Day 7. Up to 67% of the dose was excreted as unchanged drug in urine. Increased α‐Gal A activity was dose related. No abnormal cardiac effects, including prolonged QTc intervals, were observed. The pharmacokinetics of migalastat were well characterized in these Phase 1 studies conducted healthy volunteers. The 150 mg dose of migalastat HCl administered BID for 7 days was generally safe and well tolerated. A TQT study demonstrated lack of a positive signal at therapeutic and supra‐therapeutic doses. Increases in α‐Gal A enzyme activity for the 150 mg dose observed in healthy subjects suggested a successful proof of mechanism for further investigations.
Pharmacokinetic Studies in Healthy Subjects for the Development of an Extended‐Release Tablet Formulation of Guaifenesin: A 505(b)(2) New Drug Application Approval
Authors: Vilson Lineau , Owen Joel S.
Published: February 2013

Guaifenesin is an expectorant used to improve mucociliary clearance (MCC) and relieve chest congestion from upper respiratory tract infections. Immediate‐release (IR) guaifenesin requires dosing every 4 hours to maintain efficacy because of the drug's short half‐life. Extended‐release (ER) guaifenesin has been developed to prolong efficacy and reduce dosing frequency. As part of the 505(b)(2) new drug application (NDA), the pharmacokinetics (PK) of an ER bi‐layer tablet formulation of guaifenesin (Mucinex®) and bioequivalence to an over‐the‐counter (OTC) monograph IR formulation were evaluated in healthy subjects. In one study, subjects received 1,200 mg ER guaifenesin every 12 hours or 400 mg IR guaifenesin every 4 hours for 6 days. Steady‐state exposures were equivalent between the two products, as demonstrated by AUC and Cmax. In another study, subjects received a single dose of 600 mg (fasted) or 1,200 mg (fasted or fed) ER bi‐layer tablet formulations. AUC and Cmax were equivalent between both states for the 1,200 mg ER dose. However, Tmax of 1,200 mg ER guaifenesin was later in the fed than the fasted state. ER guaifenesin is bioequivalent to corresponding OTC monograph doses of IR guaifenesin. ER guaifenesin offers a convenient 12‐hour dosing alternative to 4‐hour dosing of IR guaifenesin.
A Simple Method for Fabricating Patterned Curvilinear Microstructures in Poly(dimethylsiloxane) by Selective Wetting
Authors: Ke Xi , Tang Jilin
Published: February 2013

The fabrication of patterned microstructures in poly(dimethylsiloxane) (PDMS) is a prerequisite for soft lithography. Herein, curvilinear surface relief microstructures in PDMS are fabricated through a simple three‐stage approach combining microcontact printing (μCP), selective surface wetting/dewetting and replica molding (REM). First, using an original PDMS stamp (first‐generation stamp) with linear relief features, a chemical pattern on gold substrate is generated by μCP using hexadecanethiol (HDT) as an ink. Then, by a dip‐coating process, an ordered polyethylene glycol (PEG) polymer‐dot array forms on the HDT‐patterned gold substrate. Finally, based on a REM process, the PEG‐dot array on gold substrate is used to fabricate a second‐generation PDMS stamp with microcavity array, and the second‐generation PDMS stamp is used to generate third‐generation PDMS stamp with microbump array. These fabricated new‐generation stamps are utilized in μCP and in micromolding in capillaries (MIMIC), allowing the generation of surface micropatterns which cannot be obtained using the original PDMS stamp. The method will be useful in producing new‐generation PDMS stamps, especially for those who want to use soft lithography in their studies but have no access to the microfabrication facilities.
Ranking Solvent Interactions and Dielectric Constants with [Pt(mesBIAN)(tda)]: A Cautionary Tale for Polarity Determinations in Ionic Liquids
Authors: Baker Gary A. , Rachford Aaron A. , Castellano Felix N. , Baker Sheila N.
Published: February 2013

The solvatochromic properties of [Pt(mesBIAN)(tda)] are studied in traditional molecular solvents and ionic liquids and duly compared along established empirical solvent parameter scales. The charge‐transfer absorption band of [Pt(mesBIAN)(tda)] is determined to be primarily dependent upon solvent acidity and dipolarity. Notably, ionic liquids do not obey the same well‐behaved trend as molecular solvents, highlighting the complexity and domain (nano)segregation inherent to ionic liquids.
The effect of surface topography on cell shape and early ERK1/2 signaling in macrophages; linkage with FAK and Src
Authors: Ghrebi Salem , Hamilton Douglas W. , Douglas Waterfield J. , Brunette Donald M.
Published: February 2013

Implant surface topography can modulate macrophage behavior during wound healing by the production of proinflammatory cytokines. This study investigated the activation of FAK, Src, and ERK1/2 signaling intermediates of the proinflammatory ERK1/2 pathway in RAW 264.7 macrophages in response to polished (P), coarse‐grit‐blasted (B), acid etched (E), and grit‐blasted and etched (SLA) surface topographies. In addition, the effects of these topographies on cell spreading, vinculin organization, and viability were determined. Macrophages on the SLA surface changed from predominantly well‐spread cells to ones with a more spherical morphology over time. In contrast, macrophages on the P surface changed from being predominantly spherical cells to well spread. The morphological changes were associated with changes in the distribution of vinculin. The overall patterns of the pFAK, pSrc, pERK1/2 levels as well as pERK1/2 nuclear translocation associated with cell shape with greater activation being seen with a more spread morphology. These results suggest that surface topography differentially activates signaling pathways that affect cell function and raise the possibility that topographies can be designed to optimize desired cell responses. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2013.
Biphasic release of protein from polyethylene glycol and polyethylene glycol/modified dextran microspheres
Authors: Nguyen Hoai X. , O'Rear Edgar A.
Published: February 2013

Dextrans show great promise for delivery of therapeutic agents. Dextran acetates (DAs) were synthesized with increasing degrees of substitution (DA1 < DA2 < DA3) by the reaction of the polysaccharide dextran (70 kDa) with acetic anhydride. A series of polyethylene glycol (PEG)/DA microspheres were prepared and tested with bovine serum albumin (BSA) functioning as a model protein. Particle size (0.74–0.85 μm) and encapsulation efficiency (56–70%) increased with the degree of substitution along with a slower release rate of protein from PEG/DA microspheres. Time to release 90% of protein rose from 31 to 118 min. Percentage of BSA released from PEG and PEG/DA3 microspheres with time (min) was modeled mathematically [YPEG = 100(1 − e−0.12t); YPEG/DA3 = 100(1 − e−0.024t)] to predict cumulative delivery from mixtures in vitro over a period of hours when constrained to a target level at 30 min. The system is examined for potential application in thrombolytic therapy. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 101A: 2699–2705, 2013.
Active protein and calcium hydroxyapatite bilayers grown by laser techniques for therapeutic applications
Authors: Motoc M. M. , Axente E. , Popescu C. , Sima L. E. , Petrescu S. M. , Mihailescu I. N. , Gyorgy E.
Published: February 2013

Active protein and bioceramic calcium hydroxyapatite (HA) bilayers were grown by combining conventional pulsed laser deposition (PLD) and matrix–assisted pulsed laser evaporation (MAPLE) techniques. A pulsed UV KrF* excimer laser was used for the irradiations. The HA layers were grown by PLD. Proteins with antimicrobial action were attached to the bioceramic layers using MAPLE. The composite MAPLE targets were obtained by dissolving the proteins powder in distilled water. The crystalline status and chemical composition of the obtained structures were studied by X‐ray diffractometry and Fourier transform infrared spectroscopy. The layers were grown for the design of advanced future metal implants coatings, ensuring both enhanced bone formation and localized antimicrobial therapy. Our results demonstrated that protein coatings improve bone cell proliferation in vitro. Immunofluorescence experiments show that actin filaments stretch throughout bone cells and sustain their optimal spreading. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 101A: 2706–2711, 2013.
Complete mitochondrial genome of the aluminum‐tolerant fungusRhodotorula taiwanensisRS1 and comparative analysis ofBasidiomycotamitochondrial genomes
Authors: Zhao Xue Qiang , Aizawa Tomoko , Schneider Jessica , Wang Chao , Shen Ren Fang , Sunairi Michio
Published: February 2013

The complete mitochondrial genome ofRhodotorula taiwanensisRS1, an aluminum‐tolerantBasidiomycotafungus, was determined and compared with the known mitochondrial genomes of 12Basidiomycotaspecies. The mitochondrial genome ofR. taiwanensisRS1 is a circularDNAmolecule of 40,392 bp and encodes the typical 15 mitochondrial proteins, 23tRNAs, and small and largerRNAs as well as 10 intronic open reading frames. These genes are apparently transcribed in two directions and do not show syntenies in gene order with other investigatedBasidiomycotaspecies. The average G+C content (41%) of the mitochondrial genome ofR. taiwanensisRS1 is the highest among theBasidiomycotaspecies. Two introns were detected in the sequence of theatp9gene ofR. taiwanensisRS1, but not in that of otherBasidiomycotaspecies.Rhodotorula taiwanensisis the first species of the genusRhodotorulawhose full mitochondrial genome has been sequenced; and the data presented here supply valuable information for understanding the evolution of fungal mitochondrial genomes and researching the mechanism of aluminum tolerance in microorganisms.
Comments on Peierls‐distorted Indium Chains in In4Se3–x
Authors: Osters Oliver , Blazek Gustavo , Nilges Tom
Published: February 2013

Nominal In4Se3–x with x = 0.65, derived from the prototype compound In4Se3, is a good thermoelectric material achieving a Z value of 1.48 at 705 K. This value is close to state of the art thermoelectric materials. In literature this special behavior is explained by a Peierls‐distortion or Charge Density Wave within the compound caused by the selenium deficit. While extensive thermoelectric studies for different compositions are reported in literature, a solid proof of the existence of selenium deficit samples is still missing. In this work we report about the synthesis, phase analyses, and temperature dependent single crystal determinations of In4Se3–x samples in order to clarify these structural features.
Understorey structure and refuges from predators influence habitat use by a small ungulate, the Indian chevrotain (Moschiolaindica) in Western Ghats, India
Authors: Sridhara Sachin , Edgaonkar Advait , Kumar Ajith
Published: February 2013

The availability of refuges from predators and high quality food are thought to determine habitat use in small ungulates. We tested this hypothesis on habitat use by the Indian chevrotain in a tropical rainforest in the Western Ghats, using pellet‐groups to infer habitat use. Between December 2009 and April 2010, we sampled 204 grids of 50 m × 50 m with four spatial replicates in each, using occupancy framework. We quantified refuges such as fallen logs and boulders, understorey complexity, and noted the presence of fruiting trees in the grid. Detection probability, p, of pellet‐groups was estimated at 0.61. The naive estimate of occupancy was 0.52, which increased to 0.73 when p was accounted for. Out of eight candidate models compared using AICC, the one with the number of refuges and understorey complexity was the best model. Both covariates had non‐zero positive slopes. Fruiting trees occurred very infrequently and did not influence habitat use, perhaps because the chevrotain fed more on buds, shoots and young leaves during the dry period covered by this study. The strong influence of understorey complexity on habitat use was perhaps also due to the abundance of these food items. These results highlight the need to control human use that adversely impacts the availability of refuges and understorey complexity such as removal of fallen logs and rattans. This study also demonstrates the application of the occupancy approach in the study of small and elusive ungulates.
Editorial
Authors: FAUTLEY MARTIN , MURPHY REGINA
Published: February 2013

Although not the first activity that we have undertaken as incoming editors, nonetheless this editorial marks our first published statement of recognition of this, and of how we see out responsibilities and policies with regard to our custodianship of the British Journal of Music Education. We would like to begin by playing tribute to our immediate predecessors, Pamela Burnard and Gary Spruce, in whose hands the journal has flourished, with increasing contributions from all corners of the world. Together they have steered the journal through to its current internationally recognised form. We are also aware that we step into positions held by very significant figures in music education, from the early days of John Paynter and Keith Swanwick onwards. We therefore approach this task with both humility and awe, but also firm resolve to take the journal and its role in music education onwards.
NONPARAMETRIC IDENTIFICATION OF ACCELERATED FAILURE TIME COMPETING RISKS MODELS
Authors: Lee Sokbae , Lewbel Arthur
Published: February 2013

We provide new conditions for identification of accelerated failure time competing risks models. These include Roy models and some auction models. In our setup, unknown regression functions and the joint survivor function of latent disturbance terms are all nonparametric. We show that this model is identified given covariates that are independent of latent errors, provided that a certain rank condition is satisfied. We present a simple example in which our rank condition for identification is verified. Our identification strategy does not depend on identification at infinity or near zero, and it does not require exclusion assumptions. Given our identification, we show estimation can be accomplished using sieves.
Measurement of Palladium Crust Thickness on Catalysts by Optical Microscopy and Image Analysis
Authors: Sorbier Loïc , Gay Anne-Sophie , Fécant Antoine , Moreaud Maxime , Brodusch Nicolas
Published: February 2013

Selective hydrogenation is an important process in petrochemistry to purify feedstock for polymer synthesis. For this process, catalysts containing metallic palladium deposited with an eggshell distribution on porous alumina are usually employed. For this kind of catalyst, the activity is known to be in close relation with the thickness of the palladium crust. As palladium oxide is brown and alumina is white, the palladium distribution in a catalyst bead before the reduction step can be characterized by optical microscopy. We propose an original and automatic procedure of optical image analysis to obtain a fast and robust method to measure the mean crust thickness of a catalyst batch and the corresponding standard deviation. The approach is validated by two different methods. First, we compared the crust thickness with those obtained by electron probe microanalysis. Then, catalytic tests of four samples with varying palladium crust thicknesses were performed and confirmed the expected correlation between activity and crust thickness measured by optical microscopy coupled with image analysis.
High-Frequency QPOs and Overstable Oscillations of Black-Hole Accretion Disks
Authors: Lai Dong , Fu Wen , Tsang David , Horak Jiri , Yu Cong
Published: February 2013

The physical origin of high-frequency QPOs (HFQPOs) in black-hole X-ray binaries remains an enigma despite many years of detailed observational studies. Although there exists a number of models for HFQPOs, many of these are simply “notions” or “concepts” without actual calculation derived from fluid or disk physics. Future progress requires a combination of numerical simulations and semi-analytic studies to extract physical insights. We review recent works on global oscillation modes in black-hole accretion disks, and explain how, with the help of general relativistic effects, the energy stored in the disk differential rotation can be pumped into global spiral density modes in the disk, making these modes grow to large amplitudes under certain conditions (“corotational instability”). These modes are robust in the presence of disk magnetic fields and turbulence. The computed oscillation mode frequencies are largely consistent with the observed values for HFQPOs in BH X-ray binaries. The approximate 2:3 frequency ratio is also expected from this model. The connection of HFQPOs with other disk properties (such as production of episodic jets) is also discussed.
Instrumental Selection Effect on the Bimodal T90 Distribution of Gamma-Ray Bursts
Authors: Qin Y. , Liang E. W. , Virgili F. J. , Zhang B.
Published: February 2013

The durations (T90) of 315 GRBs detected with Fermi/GBM (8-1000 keV) by 2011 September are calculated using the Bayesian Block method. We compare the T90 distributions between this sample and that observed with previous/current GRB missions. We show that T90 is energy-band dependent and the observed bimodal T90 distribution would be due to the instrumental selection effect.
White dwarf accretion and type Ia supernovae
Authors: Han Z. , Chen X.
Published: February 2013

Type Ia supernovae (SNe Ia) are believed to be thermonuclear explosions of carbon-oxygen white dwarfs at a mass close to the Chandrasekhar limit. However, a white dwarf at birth has a significantly lower mass and needs to accrete mass to grow to the limit for the explosion. Various progenitor models have been proposed and those models play an important role in our understanding of SNe Ia and cosmology.
Accretion Disks of Bounce-Back CVs
Authors: Tovmassian Gagik , Zharikov Sergey
Published: February 2013

We explore conditions and structure of accretion disks in the short-period Cataclysmic Variables, which have evolved beyond the period minimum. We show that the accretion disk in a system with extreme mass ratio grows in the size reaching 2:1 resonance radius and are relatively cool. They also become largely optically thin in the continuum, contributing to the total flux less than the stellar components of the system. In contrast, the viscosity and the temperature in spiral arms formed at the outer edge of the disk are higher and their contribution in continuum plays an increasingly important role. We model such disks and generate light curves which successfully simulate the observed double-humped light curves in the quiescence.
Center Black Hole Mass Determinations for Fermi Blazars
Authors: Fan J. H. , Liu Y. , Yang J. H. , Yuan Y. H. , Li Y. , Zhang Q. F.
Published: February 2013

In this paper, we estimated the black hole mass for some blazars with available variability time scales by assuming that the γ-ray emissions are from a distance of 200Rg from the center. The results show that the central black hole masses are in the range of log (M/M⊙) = 6.45 to 8.30.
Time Lag in Sgr A* Intra-Day Variability between the light curves at 90 and 102 GHz
Authors: Miyazaki Atsushi , Tsuboi Masato , Tsutsumi Takahiro
Published: February 2013

We performed the observation of the flux densities of Sgr A* at 90 and 102 GHz on 6 April 2005 using the Nobeyama Millimeter Array in order to detect the time lag between these frequencies. We constructed light curves covering a few hour with 1 min bin, and the Intra-Day Variability, which had a rising phase and intensity peak, of Sgr A* is clearly seen at both frequencies. We calculated the z-transformed discrete correlation function between the light curves of Sgr A* at 90 and 102 GHz. The derived time lag of the flares at these frequencies was approximately zero, contrary to our expectations based on the previously reported time lag at lower frequencies. If the radio flares of Sgr A* are explained by the expanding plasma model, the light curve at 90 GHz would be delayed with respect to the one at 102 GHz. However, we could not find such a delay with statistical significance in our data.
On the accretion onto the white dwarfs in symbiotic binaries: A test with the Thomson scattering process
Authors: Sekeráš Matej , Skopal Augustin
Published: February 2013

We tested the origin of the nebular radiation in the symbiotic star AG Dra, during different levels of its activity. We modeled the broad wings of the OVI 1032, 1038 Å resonance lines and HeII 1640 Å line by the Thomson scattering process, and determined the electron-scattering optical depth, τe, of the symbiotic nebula. The increase of τe during active phases results from an increase in the accretion rate onto the white dwarf.
The evolution of inner disk radius with orbital phase in Circinus X-1
Authors: Wang Yanan , Ding Guoqiang , Huang Chunping
Published: February 2013

Using RXTE observations, we investigate the evolution of inner disk radius (Rin) of Cir X-1 during two cycles and find obvious orbital modulation. We argue that the modulation is attributed to its high orbital eccentricity. The disk luminosity is inversely with the inner disk temperature (kTin), which is ascribed to the slow increase of kTin and, however, the rapid decrease of Rin during the passage for the neutron star to depart from the companion star.
Radiation Properties of GeV Narrow Line Seyfert 1 Galaxies
Authors: Zhang Jin , Sun X. N. , Zhang S. N. , Liang E. W.
Published: February 2013

The broadband SEDs of four gamma-ray NLS1s are compiled and explained with the leptonic model. It is found that their characteristics and fitting parameters of the observed SEDs are more like FSRQs than BL Lacs.
The Radius Estimation of Double Pulsar PSR J0737-3039A
Authors: Zhao H. H. , Song L. M.
Published: February 2013

We investigate the radius of the recycled pulsar in double pulsar PSR J0737-3039. In the standard accretion spin-up model, the recycled pulsar spin up continues until arriving at a minimum spin period, or so-called “equilibrium period”, which is related to stellar magnetic field, accretion rate, mass and radius. If present spin period is much longer than that at birth, the spin-down age can give the realistic true age estimation for normal pulsar J0737-3039B. Base on the above conditions, we estimate the radius of millisecond pulsar (MSP) J0737-3039A by assuming its true age is same as the spin-down age of its companion J0737-3039B. We obtained that the radius of J0737-3039A ranges approximately from 5 to 27 km.
The correlations between optical variability and physical parameters of quasars in SDSS Stripe 82
Authors: Zuo Wenwen , Wu Xue-Bing , Liu Yi-Qing , Jiao Cheng-Liang
Published: February 2013

We investigate the optical variability of 7658 quasars from SDSS Stripe 82. Taking advantage of a larger sample and relatively more data points for each quasar, we estimate variability amplitudes and divide the sample into small bins of redshift, rest-frame wavelength, black hole mass, Eddington ratio, and bolometric luminosity, respectively, to investigate the relationships between variability and these parameters. An anti-correlation between variability and rest-frame wavelength is found. The variability amplitude of radio-quiet quasars shows almost no cosmological evolution, but that of radio-loud ones may weakly anti-correlate with redshift. In addition, variability increases as either luminosity or Eddington ratio decreases. However, the relationship between variability and black hole mass is uncertain; it is negative when the influence of Eddington ratio is excluded, but positive when the influence of luminosity is excluded. The intrinsic distribution of variability amplitudes for radio-loud and radio-quiet quasars are different. Both radio-loud and radio-quiet quasars exhibit a bluer-when-brighter chromatism. Assuming that quasar variability is caused by variations of accretion rate, the Shakura–Sunyaev disk model can reproduce the tendencies of observed correlations between variability and rest-frame wavelength, luminosity as well as Eddington ratio, supporting that changes of accretion rate play an important role in producing the observed optical variability. However, the predicted positive correlation between variability and black hole mass seems to be inconsistent with the observed negative correlation between them in small bins of Eddington ratio, which suggests that other physical mechanisms may still need to be considered in modifying the simple accretion disk model.
Insight into S-adenosylmethionine biosynthesis from the crystal structures of the human methionine adenosyltransferase catalytic and regulatory subunits
Authors: Shafqat Naeem , Muniz Joao R. C. , Pilka Ewa S. , Papagrigoriou Evangelos , von Delft Frank , Oppermann Udo , Yue Wyatt W.
Published: February 2013

MAT (methionine adenosyltransferase) utilizes L-methionine and ATP to form SAM (S-adenosylmethionine), the principal methyl donor in biological methylation. Mammals encode a liver-specific isoenzyme, MAT1A, that is genetically linked with an inborn metabolic disorder of hypermethioninaemia, as well as a ubiquitously expressed isoenzyme, MAT2A, whose enzymatic activity is regulated by an associated subunit MAT2B. To understand the molecular mechanism of MAT functions and interactions, we have crystallized the ligand-bound complexes of human MAT1A, MAT2A and MAT2B. The structures of MAT1A and MAT2A in binary complexes with their product SAM allow for a comparison with the Escherichia coli and rat structures. This facilitates the understanding of the different substrate or product conformations, mediated by the neighbouring gating loop, which can be accommodated by the compact active site during catalysis. The structure of MAT2B reveals an SDR (short-chain dehydrogenase/reductase) core with specificity for the NADP/H cofactor, and harbours the SDR catalytic triad (YxxxKS). Extended from the MAT2B core is a second domain with homology with an SDR sub-family that binds nucleotide-sugar substrates, although the equivalent region in MAT2B presents a more open and extended surface which may endow a different ligand/protein-binding capability. Together, the results of the present study provide a framework to assign structural features to the functional and catalytic properties of the human MAT proteins, and facilitate future studies to probe new catalytic and binding functions.
Effect of pH, Buffer, and Viscosity on the Photolysis of Formylmethylflavin: A Kinetic Study
Authors: Ahmad Iqbal , Mirza Tania , Iqbal Kefi , Ahmed Sofia , Sheraz Muhammad Ali , Vaid Faiyaz H. M.
Published: February 2013

The kinetics of the photolysis of formylmethylflavin, a major intermediate product in the aerobic and anaerobic photolysis of riboflavin, was studied in the pH range 2.0–11.0. Formylmethylflavin and its photoproducts, lumichrome and lumiflavin, were determined in degraded solutions using a specific multicomponent spectrophotometric method. The photolysis of formylmethylflavin in alkaline medium takes place by first-order kinetics and the rate constants (kobs) at pH 7.5–11.0 range from 0.27 × 10–4 to 3.88 × 10–4 and 0.36 × 10–4 to 5.63 × 10–4 s–1 under aerobic and anaerobic conditions respectively. In acid medium, the photolysis involves a second-order mechanism and the rate constants at pH 2.0–7.0 range from 1.37 to 2.11 and 2.03 to 2.94 M–1 s–1 under aerobic and anaerobic conditions respectively. The rate–pH profiles for the photolysis reactions indicate the highest rate of formylmethylflavin degradation is at ~pH 4 and above pH 10. In the alkaline region, the increase in rate with pH is due to higher reactivity of the flavin triplet state. The photolysis of formylmethylflavin is catalyzed by phosphate ions and is affected by the solvent viscosity.
A generalized mathematical framework for estimating the residue function for arbitrary vascular networks
Authors: Park Chang Sub , Payne Stephen J.
Published: February 2013

The microvasculature plays a vital part in the cardiovascular system. Any impairment to its function can lead to significant pathophysiological effects, particularly in organs such as the brain where there is a very tight coupling between structure and function. However, it is extremely difficult to quantify the health of the microvasculature
in vivo
, other than by assessing perfusion, using techniques such as arterial spin labelling. Recent work has suggested that the flow distribution within a voxel could also be a valuable measure. This can also be measured clinically, but as yet has not been related to the properties of the microvasculature due to the difficulties in modelling and characterizing these strongly inter-connected networks. In this paper, we present a new technique for characterizing an existing physiologically accurate model of the cerebral microvasculature in terms of its residue function. A new analytical mathematical framework for calculation of the residue function, based on the mass transport equation, of any arbitrary network is presented together with results from simulations. We then present a method for characterizing this function, which can be directly related to clinical data, and show how the resulting parameters are affected under conditions of both reduced perfusion and reduced network density. It is found that the residue function parameters are affected in different ways by these two effects, opening up the possibility of using such parameters, when acquired from clinical data, to infer information about both the network properties and the perfusion distribution. These results open up the possibility of obtaining valuable clinical information about the health of the microvasculature
in vivo
, providing additional tools to clinicians working in cerebrovascular diseases, such as stroke and dementia.
Applications of analysis of dynamic adaptations in parameter trajectories
Authors: van Riel Natal A. W. , Tiemann Christian A. , Vanlier Joep , Hilbers Peter A. J.
Published: February 2013

Metabolic profiling in combination with pathway-based analyses and computational modelling are becoming increasingly important in clinical and preclinical research. Modelling multi-factorial, progressive diseases requires the integration of molecular data at the metabolome, proteome and transcriptome levels. Also the dynamic interaction of organs and tissues needs to be considered. The processes involved cover time scales that are several orders of magnitude different. We report applications of a computational approach to bridge the scales and different levels of biological detail. Analysis of dynamic adaptations in parameter trajectories (ADAPTs) aims to investigate phenotype transitions during disease development and after a therapeutic intervention. ADAPT is based on a time-dependent evolution of model parameters to describe the dynamics of metabolic adaptations. The progression of metabolic adaptations is predicted by identifying necessary dynamic changes in the model parameters to describe the transition between experimental data obtained during different stages. To get a better understanding of the concept, the ADAPT approach is illustrated in a theoretical study. Its application in research on progressive changes in lipoprotein metabolism is also discussed.
Multiscale modelling of insulin secretion during an intravenous glucose tolerance test
Authors: Pedersen Morten Gram , Cobelli Claudio
Published: February 2013

Dysfunctional insulin secretion from pancreatic β-cells plays a major role in the development of diabetes. The intravenous glucose tolerance test (IVGTT) is a widely used clinical test to assess β-cell function. The analysis of IVGTT data is conveniently performed using mathematical models, which need to be fairly simple to enable parameter identifiability (minimal models), but should at the same time have sound biological foundation at the cellular level. Using mathematical analysis and model reduction, we show here that our recent mathematical model of insulin secretory granule dynamics in β-cells provides mechanistic underpinning for our minimal model of pancreatic insulin secretion during an IVGTT.
Integrative approaches to computational biomedicine
Authors: Coveney Peter V. , Diaz-Zuccarini Vanessa , Graf Norbert , Hunter Peter , Kohl Peter , Tegner Jesper , Viceconti Marco
Published: February 2013

The new discipline of computational biomedicine is concerned with the application of computer-based techniques and particularly modelling and simulation to human health. Since 2007, this discipline has been synonymous, in Europe, with the name given to the European Union's ambitious investment in integrating these techniques with the eventual aim of modelling the human body as a whole: the virtual physiological human. This programme and its successors are expected, over the next decades, to transform the study and practice of healthcare, moving it towards the priorities known as ‘4P's’: predictive, preventative, personalized and participatory medicine.
Fgf20 governs formation of primary and secondary dermal condensations in developing hair follicles
Authors: Huh Sung-Ho , Närhi Katja , Lindfors Päivi H. , Häärä Otso , Yang Lu , Ornitz David M. , Mikkola Marja L.
Published: February 2013

In hair follicle development, a placode-derived signal is believed to induce formation of the dermal condensation, an essential component of ectodermal organs. However, the identity of this signal is unknown. Furthermore, although induction and patterning of hair follicles are intimately linked, it is not known whether the mesenchymal condensation is necessary for inducing the initial epithelial pattern. Here, we show that fibroblast growth factor 20 (Fgf20) is expressed in hair placodes and is induced by and functions downstream from epithelial ectodysplasin (Eda)/Edar and Wnt/β-Catenin signaling to initiate formation of the underlying dermal condensation. Fgf20 governs formation of primary and secondary dermal condensations in developing hair follicles and subsequent formation of guard, awl, and auchene hairs. Although primary dermal condensations are absent in Fgf20 mutant mice, a regular array of hair placodes is formed, demonstrating that the epithelial patterning process is independent of known histological and molecular markers of underlying mesenchymal patterns during the initial stages of hair follicle development.
Electronic government as a paradigm shift for efficient public services
Authors: Asogwa Brendan E.
Published: February 2013

Purpose

Nigeria has set up an e‐government initiative termed the “National e‐Government Strategy” (NeGSt) for the purpose of using ICT infrastructure to enhance public services. It was expected that e‐government would enable the Nigerian government at all levels to render efficiencies in the public sector, ensure higher productivity and economic growth, foster national competitiveness and lead to the attainment of the vision 20‐2020. Regrettably, the e‐services envisaged seem not to be impacting much on public service delivery in the country. The aim of this paper is to examine the benefits and the status of e‐government in Nigeria, the barriers to the accomplishment of the goal, and some ways out.

Design/methodology/approach

A total of ten federal government ministries in Nigeria that have an official website were sampled. The study population was 100 randomly drawn employees in the ministries, and a structured questionnaire and oral interviews were used. Data were analyzed using frequency tables, simple percentages, and bar charts.

Findings

The study finds that e‐government would provide faster access to government information, lower administrative costs, increase transparency in government ministries, and reduce bribery and corruption, among others. These opportunities are threatened by low bandwidth and internet penetration, inadequate ICT infrastructure and technicians, incessant power outages, technological obsolescence, and other barriers. The Nigerian government should carry out a SWOT analysis of the e‐government project in the country, strengthen the e‐government infrastructure and ensure steady power supply before embarking on the e‐government project again.

Practical implications

This paper exposes the challenges and strategies for the e‐government initiative in Nigeria. It will help leaders to see areas of weakness and the need to re‐strategize. The paper serves as a beacon for further research and discussion on e‐government and online public services in developing countries.

Originality/value

This paper exposes the challenges and strategies for the e‐government initiative in Nigeria and suggests some measures for e‐government to develop and to improve.
A folk theory of meetings – and beyond
Authors: Ravn Ib
Published: February 2013

Purpose

Despite widespread frustration with meetings in organizations, they receive very little attention from academics. The purpose of this paper is to shed conceptual light on meetings and hence render them amenable to research and development.

Design/methodology/approach

From interviews with managers and employees, six common assumptions about meetings were extracted, termed a folk theory of meetings, which most office workers seem to carry in the back of their minds.

Findings

This folk theory holds meetings to be places for excessive talk, whether by a domineering leader or highly vocal participants, the purpose of which is to walk through the items on the agenda and dispose of each. This bleak and conservative concept of a meeting impedes intellectual as well as practical progress.

Practical implications

An alternative theory of meetings is proposed, one based on the group facilitation approach to social order in meetings. On this view, a facilitator can change meetings by controlling their form and process, providing direction, stimulating engagement and ensuring that the meeting creates value for its external stakeholders and meaning for its participants. If adopted in management training, this view of meetings – and the widely available facilitation tools that go with it – may render meetings at work the subject of conscious organizational development.

Originality/value

The proposed “folk theory of meetings” is novel, as is the contrast provided with the facilitation approach to meetings. Together, they constitute a reconceptualization that can be used to move meetings out of the organizational doldrums.
The “state of art” of organisational blogging
Authors: Baxter Gavin J. , Connolly Thomas M.
Published: February 2013

Purpose

The aim of this paper is to provide an overview of the “state of art” of organisational blogging. It also aims to provide a critical review of the literature on organisational blogging and propose recommendations on how to advance the subject area in terms of academic research.

Design/methodology/approach

A systematic literature review is used to illustrate the different aspects of research currently associated with organisational blogging and how these studies have advanced the field of organisational learning.

Findings

The results of the systematic literature review indicate that though research into organisational blogging is increasing, research in this subject area is still in its infancy.

Research limitations/implications

Though this paper reviews empirical research related to organisational blogging it does not provide empirical evidence of Web 2.0 use within an actual organisation. The paper does, however, advocate and provide recommendations for further research to be undertaken within this subject area.

Originality/value

This paper contributes to the “state of art” of organisational blogging by providing a current synopsis of the area and provides the academic community with further recommendations for conducting future research into the subject. The paper also provides value to management practitioners in terms of how organisational blogs can be applied in an internal corporate context.
Psychological pricing in mergers & acquisitions using prospect theory
Authors: Agarwal Nipun , Zeephongsekul Panlop
Published: February 2013

Purpose

It is hard to accurately price a merger or acquisition, primarily as there are psychological factors that impact such pricing. As a result, it is hard for traditional financial models to accurately undertake valuations for merger or acquisition transactions. The purpose of this paper is to develop a two‐person merger and acquisition (M&A) game theoretic model that will analyse if the offer price provided by an acquirer should be equal to the mid‐point of the acquirer's offer and the target's bid price. It will also analyse if the acquirer will do better by being risk taking or risk averse and if the target will do better by optimistic or pessimistic in this model.

Design/methodology/approach

This paper analyses how an incomplete information game with prospect theory can be used to value M&A transaction more accurately by considering the impact of psychological factors on pricing.

Findings

It is found that acquirers do not always have to increase the offer price in order to successfully purchase the target firm. Based on the behavioural type of the acquirer and target, it could be possible that the acquirer could even lower the offer and the target firm would still be willing to successfully complete the M&A transaction.

Originality/value

The original aspect of this paper is that it links behavioural types to M&A valuation and the success of M&A transactions. Such a model has not been developed before and it shows that M&A transactions are not always completed by the acquirer increasing their offer price.