bluuebunny/crossref_metadata_2025 huggingface dataset:
Constraining White Dwarf Masses Via Apsidal Precession in Eccentric Double White Dwarf Binaries
Authors: Valsecchi Francesca , Farr Will M. , Willems Bart , Deloye Christopher J. , Kalogera Vicky
Published: January 2013

Galactic short period double white dwarfs (DWD) are guaranteed gravitational wave (GW) sources for the next generation of space-based interferometers sensitive to low-frequency GWs (10−4− 1 Hz). Here we investigate the possibility of constraining the white dwarf (WD) properties through measurements of apsidal precession in eccentric binaries. We analyze the general relativistic (GR), tidal, and rotational contributions to apsidal precession by using detailed He WD models. We find that apsidal precession can lead to a detectable shift in the emitted GW signal, the effect being stronger (weaker) for binaries hosting hot (cool) WDs. We find that in hot (cool) DWDs tides dominate the precession at orbital frequencies above ~0.01 mHz (~1 mHz). Analyzing the apsidal precession of these sources only accounting for GR would potentially lead to an extreme overestimate of the component masses. Finally, we derive a relation that ties the radius and apsidal precession constant of cool WD components to their masses, therefore allowing tides to be used as an additional mass measurement tool.
Population Synthesis of Type Ia SNe: Constraining Free Parameters from Observations
Authors: Moe Maxwell , Di Stefano Rosanne
Published: January 2013

Computing the rate of Type Ia supernovae (SNe Ia) from first principles is difficult because there are large uncertainties regarding several key binary processes such as common envelope evolution, tidal interactions, and the efficiency of mass transfer. Fortunately, a range of observational parameters of binaries in intermediate stages of evolution can help us model these processes in a way that is likely to mirror the true binary evolution. We discuss how this observationally-motivated approach may have the effect of increasing the predicted rate of single degenerate progenitors of SNe Ia, while simultaneously decreasing the number of double degenerate progenitors.
Type Ia Supernova Models and Progenitor Scenarios
Authors: Nomoto Ken'ichi , Kamiya Yasuomi , Nakasato Naohito
Published: January 2013

We review some recent developments in theoretical studies on the connection between the progenitor systems of Type Ia supernovae (SNe Ia) and the explosion mechanisms. (1)DD-subCh: In the merging of double C+O white dwarfs (DD scenario), if the carbon detonation is induced near the white dwarf (WD) surface in the early dynamical phase, it could result in the (effectively) sub-Chandrasekhar mass explosion. (2)DD-Ch: If no surface C-detonation is ignited, the WD could grow until the Chandrasekhar mass is reached, but the outcome depends on whether the quiescent carbon shell burning is ignited and burns C+O into O+Ne+Mg. (3)SD-subCh: In the single degenerate (SD) scenario, if the He shell-flashes grow strong to induce a He detonation, it leads to the sub-Chandra explosion. (4)SD-Ch: If the He-shell flashes are not strong enough, they still produce interesting amounts of Si and S near the surface of the C+O WD before the explosion. In the Chandra mass explosion, the central density is high enough to produce electron capture elements, e.g., stable58Ni. Observations of the emission lines of Ni in the nebular spectra provides useful diagnostics of the sub-Chandra vs. Chandra issue. The recent observations of relatively low velocity carbon near the surface of SNe Ia provide also an interesting constraint on the explosion models.
Constraining Type Ia Supernova Progenitors
Authors: Scannapieco E. , Raskin C. , Valle M. Della , Fryer C. , Rhoads J. , Rockefeller G. , Timmes F. X.
Published: January 2013

We present observational and theoretical studies constraining Type Ia supernova progenitors.

First, we use a new observational technique to show that “prompt” SNe Ia that trace star-formation on cosmic timescales exhibit a significant delay time of 200-500 million years. This implies that either the majority of SNe Ia companion stars have main-sequence masses less than three solar masses, or that most SNe Ia arise from double-white dwarf binaries.

Second we present a comprehensive study of white dwarf collisions as an avenue for creating SNe Ia. Using a smooth particle hydrodynamics code with a 13-isotope nuclear network, we show that several combinations of white dwarf masses and impact parameters produce enough 56Ni to result in luminosities ranging from those of sub-luminous to super-luminous SNe Ia, depending on the parameters of the collision.

Finally, we conduct a simulation survey of double-degenerate white dwarf mergers with varying mass combinations. Unlike previous works, we do not add detonations by hand to our simulations, and we do not find any thermonuclear explosions during the mergers. Instead, all but one of our simulations forms a cold, degenerate core surrounded by a hot disk, while our least massive pair of stars forms only a hot disk. We characterize the remnants by core mass, rotational velocity, and half-mass radius, and discuss how we will evolve them further with simulations that incorporate dissipative processes. Such simulations may indeed lead to double-degenerate Type Ia explosions that occur many orbits after the mergers themselves.
Properties of Carbon-Oxygen White Dwarf Merger Remnants
Authors: Zhu Chenchong , Chang Philip , van Kerkwijk Marten , Wadsley James
Published: January 2013

Recent studies have shown that for suitable initial conditions both super- and sub-Chandrasekhar mass carbon-oxygen white dwarf mergers produce explosions similar to observed SNe Ia. The question remains, however, how much fine tuning is necessary to produce these conditions. We performed a large set of SPH merger simulations, sweeping the possible parameter space. We find trends for merger remnant properties, and discuss how our results affect the viability of our recently proposed sub-Chandrasekhar merger channel for SNe Ia.
Connecting Recurrent Novae to [Some] Type Ia Supernovae
Authors: Patat Ferdinando
Published: January 2013

In this review, I summarize the observational attempts made so far to unveil the nature of the progenitor system(s) of Type Ia supernovae. In particular, I focus on the most recent developments that followed the claimed detection of circumstellar material around a few events, and on the link this possibly establishes with recurrent novae. In this framework, I then discuss the case of RS Oph, what we know of its circumstellar environment, and what this is telling us about its supposed connection to Type Ia supernovae explosions.
Evidence for Circumstellar Material in Type Ia Supernovae via Sodium Absorption Features
Authors: Sternberg Assaf
Published: January 2013

Type Ia supernovae are very good tools for measuring distances on a cosmic scale. The consensus view is that mass transfer onto a white dwarf in a close binary system leads to a thermonuclear explosion, though the nature of the mass donor is still uncertain. In the single-degenerate model it is a main-sequence star or an evolved star. In the double-degenerate model it is another white dwarf. We study the velocity structure of absorbing material along the line of sight to 35 Type Ia supernovae and find a statistical preference for blueshifted structures, likely arising in gas outflows from the supernova progenitor systems, consistent with a single-degenerate progenitor for a substantial fraction of Type Ia supernovae in nearby spiral galaxies.
Light Curve Models for SN 2009dc
Authors: Kamiya Yasuomi
Published: January 2013

Simplified explosion models of super-Chandrasekhar-mass C-O white dwarfs (WDs) are constructed with parameters such as WD mass and 56Ni mass. Their light curves are obtained by solving one-dimensional equations of radiation hydrodynamics, and compared with the observations of SN 2009dc, one of the overluminous Type Ia supernovae, to estimate its properties. As a result, the progenitor of SN 2009dc is suggested to be a 2.2–2.4-M⊙ C-O WD with 1.2–1.4 M⊙ of 56Ni, if the extinction by its host galaxy is negligible.
Progenitor's Signatures in Type Ia Supernova Remnants
Authors: Chiotellis A. , Kosenko D. , Schure K. M. , Vink J.
Published: January 2013

The remnants of Type Ia supernovae (SNe Ia) can provide important clues about their progenitor histories. We discuss two well-observed supernova remnants (SNRs) that are believed to have resulted from SNe Ia, and use various tools to shed light on the possible progenitor histories. We find that Kepler's SNR is consistent with a symbiotic binary progenitor consisting of a white dwarf and an AGB star. Our hydrosimulations can reproduce the observed kinematic and morphological properties. For Tycho's remnant we use the characteristics of the X-ray spectrum and kinematics to show that the ejecta has likely interacted with dense circumstellar gas.
Saltatory formation, sliding and dissolution of ER–PM junctions in migrating cancer cells
Authors: Dingsdale Hayley , Okeke Emmanuel , Awais Muhammad , Haynes Lee , Criddle David N. , Sutton Robert , Tepikin Alexei V.
Published: January 2013

We demonstrated three novel forms of dynamic behaviour of junctions between the ER (endoplasmic reticulum) and the PM (plasma membrane) in migrating cancer cells: saltatory formation, long-distance sliding and dissolution. The individual ER–PM junctions formed near the leading edge of migrating cells (usually within 0.5 μm of polymerized actin and close to focal adhesions) and appeared suddenly without sliding from the interior of the cell. The long distance sliding and dissolution of ER–PM junctions accompanied the tail withdrawal.
Sensor selection in magnetic tracking based on convex optimisation
Authors: Talcoth O. , Rylander T.
Published: January 2013

The performance of a magnetic tracking system is substantially influenced by the positions of its sensors. To optimise these sensor positions, exploited is a performance metric based on the Fisher information matrix and a convex relaxation of sensor selection problem. Optimised sensor positions are presented for a magnetic tracking system with a planar sensor array and a measurement domain consisting of one point.
Probability density for envelope of multiplicative noise
Authors: Goodman J. , Bertoncini C.
Published: January 2013

The closed‐form probability density for the envelope of multiplicative noise, both for the zero and nonzero mean case, is considered. The distribution parameters are determined using a curve fitting optimisation that shows excellent agreement between the measured and parametric form of the density function.
Application of co‐ordinate transformation for 3‐DOF motor's vector control
Authors: Park H.J. , Go S.C. , Lee H.J. , Cho S.Y. , Lee K.D. , Ahn H.W. , Lee J.
Published: January 2013

Vector control provides a fast torque response for motor control. In general, the vector control is used for the control of a rotary machine. In the case of the 3‐degree‐of‐freedom (3‐DOF) motor, the position of the rotor is changed on three‐dimensional space by tilting and rotating the motion of the shaft. Thus, when applying the vector control to the 3‐DOF motor, the 3D co‐ordinate transformation algorithm is required to decouple not only the field and torque current but the positioning (or tilting) current. The reliability of the proposed control algorithm was proven via experiments.
Transport‐based equivalent circuit for semiconductor nanoparticle in terahertz frequency range
Authors: Shen T. , Hu Z. , Wong T.
Published: January 2013

By consideration of the physical process of charge carrier motion and lattice polarisation, an equivalent circuit for a semiconductor nano‐particle in the terahertz frequency range is obtained. All circuit elements are of electrical nature and can be directly expressed in terms of material parameters. When the generalised admittance of the circuit is multiplied by the intensity of an externally applied field, the total induced dipole moment of the nanoparticle results, which is in good match to that given by field analysis and simulation. The readily obtained polarisability can serve as the basis of analysis for composite structures and aggregates of which the nanoparticle is a constituent.
Inherently non‐resonant multi‐band mobile terminal antenna
Authors: Valkonen R. , Ilvonen J. , Icheln C. , Vainikainen P.
Published: January 2013

An inherently non‐resonant capacitive coupling element antenna for mobile handsets is presented. The compact antenna includes a simple coupling element with a novel multi‐band matching circuit for simultaneous 698–960 and 1710–2690 MHz operation. Experimental results show that the antenna performs strongly in comparison to the current state‐of‐the‐art in mobile terminal antennas, and that the non‐resonant antenna is a competitive choice for mobile terminals.
Inspection of electrical wires for insulation faults and current surges using sliding temperature sensor based on optical Microfibre coil resonator
Authors: Chen G.Y. , Brambilla G. , Newson T.P.
Published: January 2013

Presented is a compact and robust temperature sensor based on an optical microfibre to coil resonator packaged around a Teflon tube. The probe can efficiently slide along electrical wires to map the local temperature for locating insulation faults and reporting high current surges. A temperature responsivity of 95 pm/°C up to ~80°C was demonstrated. This sensor is potentially low cost and simple to fabricate, making it attractive for domestic and industrial applications.
Multi‐step extended‐counting analogue‐to‐digital converters
Authors: Chen C.‐H. , Jung Y. , Ceballos J.L. , Temes G.C.
Published: January 2013

Extended‐counting A/D converters are proposed which achieve a high accuracy by performing the conversion in several cycles. During the first cycle, the circuit performs as an incremental ADC, while during the remaining ones it acts as a multi‐slope counting converter. With only one opamp and a single‐slope ADC, the accuracy is comparable to that of a second‐order incremental ADC. A three‐step A/D converter using only a single opamp and a two‐slope ADC achieves an accuracy comparable to that of a third‐order incremental ADC, but with much higher power efficiency.
460 μW 32 dB image rejection ratio second‐order active‐RC complex filter with improved power efficient opamp
Authors: Wang J. , Ye L. , Chen L. , Liu J. , Liao H.
Published: January 2013

An ultra‐low‐power second‐order Chebyshev active‐RC complex filter for a low‐IF ultra‐low‐power receiver is presented. By utilising a pole‐cancellation push‐pull buffer with feedforward phase compensation technology, the operational amplifier (opamp) realises superior stability while maintaining high gain bandwidth and ultra‐low power consumption. A second‐order complex filter with four proposed opamps and an adaptive bias fabricated in standard 180 nm CMOS process consumes only 460 μW at 1.8 V power supply. The measured centre frequency is 3 MHz and bandwidth is 2 MHz, while it achieves 32 dB image rejection ratio at the centre frequency.
Hardware‐efficient phase‐detection technique for digital clock and data recovery
Authors: Zargaran‐Yazd A. , Keikhosravy K. , Rashtian H. , Mirabbasi S.
Published: January 2013

A phase‐detection technique for digital clock and data recovery (CDR) in multi‐Gbit/s serial links is presented. Compared to conventional sampling‐based receivers, hardware efficiency at the system‐level is achieved by extracting timing information from analysing the occurrence of certain patterns at the output of four comparators. The arrangement of the decision threshold and sampling time of these comparators is discussed, and the phase and frequency detection characteristic of such an arrangement is evaluated. The technique is validated through a proof‐of‐concept 12.5 Gbit/s CDR chip that is fabricated in 90nm CMOS.
Effect of electric field on exciton in high‐purity GaAs epilayer measured at room temperature
Authors: Kayastha M.S. , Sapkota D.P. , Takahashi M. , Wakita K.
Published: January 2013

The excitonic electroabsorption has been investigated for a high‐purity GaAs epilayer of 10 µm thickness at room temperature and clear red‐shift (≃1.44 nm) of the excitonic absorption peak has been observed. An extinction ratio over 10 dB has been obtained with an applied voltage of 11 V, which is nearly five times larger than the theoretical estimation without considering the exciton. This may be the first observation for of a surface normal structure with a polyaniline as a transparent Schottky electrode. The insertion loss is estimated to be 3 dB. This relative low driving voltage for a bulk configuration without quantum wells is due to high‐purity GaAs.
ΔΣ digital‐RF transmitter with reduced LO leakage using segmented butterfly shufflers
Authors: Shim S. , Lee H.Y. , Choi J.‐H. , Yu H.‐K. , Hong S.
Published: January 2013

Presented is a digital‐RF transmitter using multi‐bit ΔΣ modulators with noise‐shaped segmentation and butterfly shufflers for shaping mismatches between digital‐to‐RF converter (DRFC) cells. The segmented butterfly shufflers prevent mismatch errors of DRFCs from aggravating the linearity and the LO leakage of the transmitter. A prototype based on a digitally‐intensive top‐down design is fabricated in 90 nm CMOS process. Measurement results for wideband‐code division multiple access demonstrate an adjacent channel leakage ratio (ACLR) (5 MHz/10 MHz) of −49.6 dBc/−53.9 dBc and an Error Vector Magnitude of 1.89% with a main channel output power of −0.1 dBm centred at 1.95 GHz.
Polarisation state optimisation in observing Brillouin scattering signal in polymer optical fibres
Authors: Mizuno Y. , Hayashi N. , Nakamura K.
Published: January 2013

In general, the state of polarisation (SOP) should be adjusted to optimise the signal‐to‐noise ratio of Brillouin measurement based on self‐heterodyne detection. Although Brillouin Stokes power in silica fibres is known to be enhanced by optimising the SOP, the role of SOP optimisation in polymer optical fibres (POFs) is quite different from that in silica fibres. In this reported work, it is clarified that the role of SOP optimisation in POFs lies not in enhancing the Brillouin Stokes power but in suppressing the tail of the Rayleigh‐scattered light spectrum.
High efficiency GaN current‐mode class‐D amplifier at 2.6 GHz using pure differential transmission line filters
Authors: Sigg A. , Heck S. , Bräckle A. , Berroth M.
Published: January 2013

In class‐D operation the impedances of the output network at each harmonic frequency at the intrinsic terminals of the transistors are of main importance. This reported work demonstrates a new concept using pure differential transmission line filters for the matching of these impedances. Furthermore, de‐embedding techniques are used to compensate the impedance transforming characteristics of the package parasitics. A current‐mode class‐D (CMCD) amplifier with a power‐added efficiency (PAE) of 62% and a corresponding output power of 29.5 W at 2.6 GHz has been demonstrated. To the authors' knowledge, these are the highest reported values of the PAE as well as the output power at this frequency for a CMCD.
Electronic and optical properties of metal-nanoparticle filled graphene sandwiches
Authors: Zaniewski Anna M. , Schriver Maria , Gloria Lee J. , Crommie M. F. , Zettl A.
Published: January 2013

We sandwich gold nanoparticles between graphene sheets and contrast the electronic and optical properties of these hybrid structures to those of single layer graphene with and without gold nanoparticle overlayers, and laminated unfilled double layers. Undecorated graphene has the highest sheet resistance while filled sandwiches have the lowest. The optical extinction spectrum for sandwiches is redshifted and broadened compared to decorated single layer graphene. We also find that the presence of gold nanoparticles in sandwiches shifts the work function relative to unfilled double-layer graphene. The low sheet resistance and favorable optical properties of metal-filled sandwiches make them attractive candidates for optoelectronic applications.
An in situ x-ray photoelectron spectroscopy study of the initial stages of rf magnetron sputter deposition of indium tin oxide on p-type Si substrate
Authors: Rein M. H. , Hohmann M. V. , Thøgersen A. , Mayandi J. , Holt A. O. , Klein A. , Monakhov E. V.
Published: January 2013

The interface between indium tin oxide and p-type silicon is studied by in situ X-ray photoelectron spectroscopy (XPS). This is done by performing XPS without breaking vacuum after deposition of ultrathin layers in sequences. Elemental tin and indium are shown to be present at the interface, both after 2 and 10 s of deposition. In addition, the silicon oxide layer at the interface is shown to be composed of mainly silicon suboxides rather than silicon dioxide.
Influences of boundary layer scale separation on the vorticity transport contribution to turbulent inertia
Authors: Morrill-Winter C. , Klewicki J.
Published: January 2013

In the flows of interest, the mean effect of turbulent inertia can be expressed as the difference of two velocity vorticity correlations. This difference must be sufficiently non-zero if turbulent inertia is to have a net influence on the mean dynamics. One of the correlations is physically related to change of scale effects, while the other is related to advective vorticity transport. The vorticity transport mechanism is studied under the influence of increasing scale separation. Through the use of both laboratory and field data, the scale separation between the fluctuations of wall-normal velocity, v, and spanwise vorticity ωz, are shown to increase with distance from the wall and Reynolds number. Time-delayed correlations between these quantities reveal that only slight variations in their average phase would cause significant variations in the mean transport of momentum. Spectra are used to explore previous observations of scale selection between v and ωz. The wavelengths corresponding to the peaks in the v and ωz spectra are used to describe scale separation effects. The variations in the wavelength ratios are shown to correlate with the scaling properties that follow from the magnitude ordering of terms in the mean momentum equation. Scale separation is seen to result from two mechanisms: spatial confinement and spatial dispersion. The influence of vorticity stretching apparently generates motions bearing concentrated vorticity that, with increasing Reynolds number, are confined to a smaller fraction of the region where the mean viscous force is of leading order. Where the mean dynamics are inertially dominated, the characteristic vortical motions are advectively dispersed. The width of this domain asymptotically grows like the boundary layer thickness. In the region y+ ≲ 40, the streamwise correlation lengths of v and ωz are shown to scale with the square root of the Reynolds number. This is consistent with inner-outer interactions suggested by the scaling structure of the mean momentum equation.
Grad's moment method for relativistic gas mixtures of Maxwellian particles
Authors: Kremer Gilberto M. , Marques Wilson
Published: January 2013

Mixtures of relativistic gases are analyzed within the framework of Boltzmann equation by using Grad's moment method. A relativistic mixture of r constituent is characterized by the moments of the distribution function: particle four-flows, energy-momentum tensors, and third-order moment tensors. By using Eckart's decomposition and introducing 13r + 1 scalar fields – related with the four-velocity, temperature of the mixture, particle number densities, diffusion fluxes, non-equilibrium pressures, heat fluxes, and pressure deviator tensors – Grad's distribution functions are obtained. Grad's distribution functions are used to determine the third-order tensors and their production terms for mixtures whose constituent's rest masses are not too disparate, so that it follows a system of 13r + 1 scalar field equations. By restricting to a binary mixture characterized by the six fields of partial particle number densities, four-velocity and temperature, the remainder 21 scalar equations are used to determine the constitutive equations for the non-equilibrium pressures, diffusion fluxes, pressure deviator tensors, and heat fluxes. Hence the Navier-Stokes and generalized Fourier and Fick laws are obtained and the transport coefficients of bulk and shear viscosities, thermal conductivity, diffusion, thermal-diffusion, and diffusion-thermal are determined. Analytic expressions for the transport coefficients in the non-relativistic and ultra-relativistic limiting cases are given. Furthermore, solutions of the relativistic field equations for the binary mixture are obtained in form of forced and free waves. In the low frequency limiting case the phase velocity and the attenuation coefficient are determined for forced waves. In the small wavenumber limiting case it is shown that there exist four longitudinal eigenmodes, two of them corresponding to propagating sound modes and two associated with non-propagating diffusive modes.
Negative differential resistance in electron tunneling in ultrathin films near the two-dimensional limit
Authors: Batabyal R. , Abdul Wasey A. H. M. , Mahato J. C. , Das Debolina , Roy A. , Das G. P. , Dev B. N.
Published: January 2013

We report on our observation of negative differential resistance (NDR) in electron tunneling conductance in atomic-scale ultrathin Ag films on Si(111) substrates. NDR was observed by scanning tunneling spectroscopy measurements. The tunneling conductance depends on the electronic local density of states (LDOS) of the sample. We show that the sample bias voltage, at which negative differential resistance and peak negative conductance occur, depends on the film thickness. This can be understood from the variation in the LDOS of the Ag films as a function of film thickness down to the two-dimensional limit of one atomic layer. First principles density functional theory calculations have been used to explain the results.
Time-domain simulation of nonlinear radiofrequency phenomena
Authors: Jenkins Thomas G. , Austin Travis M. , Smithe David N. , Loverich John , Hakim Ammar H.
Published: January 2013

Nonlinear effects associated with the physics of radiofrequency wave propagation through a plasma are investigated numerically in the time domain, using both fluid and particle-in-cell (PIC) methods. We find favorable comparisons between parametric decay instability scenarios observed on the Alcator C-MOD experiment [J. C. Rost, M. Porkolab, and R. L. Boivin, Phys. Plasmas 9, 1262 (2002)] and PIC models. The capability of fluid models to capture important nonlinear effects characteristic of wave-plasma interaction (frequency doubling, cyclotron resonant absorption) is also demonstrated.
Reversible meiotic arrest in feline oocytes
Authors: Herrick Jason R.
Published: January 2013

Increasing intracellular concentrations of cyclic adenosine monophosphate (cAMP) within the cumulus–oocyte complex (COC) inhibits or delays spontaneous oocyte maturation and improves the developmental competence of the oocyte in many species, but information for carnivores is limited. The objectives of the present study were to describe the effects of isobutyl methylxanthine (IBMX), which decreases cAMP degradation, and forskolin, which increases cAMP production, on spontaneous and induced maturation (by equine chorionic gonadotrophin (eCG) and epidermal growth factor (EGF)) of feline oocytes and to evaluate the reversibility of IBMX-induced arrest by measuring the resumption of meiosis and embryonic development following IVF. IBMX decreased (P < 0.05) the incidence of spontaneous (6.7% vs 42.0%, metaphase II (MII)) and induced (5.6% vs 66.1% MII) maturation after 24 h of culture. In contrast, forskolin stimulated meiosis (81.7% MII; P < 0.05). Following 12 h of culture with IBMX and an additional 24 h with eCG and EGF in the absence of IBMX, the proportions of oocytes reaching MII (66.1%), cleaving (79.9%) and developing to the blastocyst stage (15.3%) were similar (P > 0.05) to oocytes cultured continuously with eCG and EGF (70.2%, 83.0% and 18.1%, respectively). These results demonstrate that IBMX reversibly inhibits both spontaneous and eCG+EGF-induced meiosis in feline oocytes without compromising the oocyte’s developmental competence.
Behavior, Growth and Habitat Selection of Hatchery Esocids Reared with Artificial Vegetation
Authors: Einfalt Lisa M. , Wojcieszak Douglas B. , Wahl David H.
Published: January 2013

We evaluated the effect of adding artificial vegetation to the rearing environment on behavior, habitat selection, and growth of hatchery esocids in laboratory experiments. First, Muskellunge Esox masquinongy and the hybrid Tiger Muskellunge (Muskellunge × Northern Pike E. lucius) resided separately in pools either with or without artificial vegetation (250 stems/m2) for 2 weeks. Both taxa raised in vegetated pools dispersed and spent more time away from the sides of the pools than did individuals residing in open pools. Tiger Muskellunge in vegetated pools also startled less often than fish in open pools, whereas vegetation did not decrease Muskellunge startle behavior. We next examined habitat selection between esocids raised in tanks with and without vegetation. Fish were tested in semivegetated pools, and for Tiger Muskellunge acclimated in vegetation, more fish (80%) used the vegetated half of the pool compared with fish raised in open tanks (61%). Muskellunge, regardless of treatment, spent a high proportion (>90%) of time in vegetation. Finally, growth of both taxa was similar between esocids reared in vegetated tanks compared with esocids reared in open tanks. The presence of artificial vegetation in tanks caused changes in behavior for both esocid taxa, but Tiger Muskellunge were more flexible in modifying their behavior. Behavioral responses resulting from exposure to vegetation could increase survival after stocking in lakes.
Deconstructing Frith and Snowling's Homograph-Reading Task: Implications for Autism Spectrum Disorders
Authors: Brock Jon , Bzishvili Samantha
Published: January 2013

The poor performance of autistic individuals on a test of homograph reading is widely interpreted as evidence for a reduction in sensitivity to context termed “weak central coherence”. To better understand the cognitive processes involved in completing the homograph-reading task, we monitored the eye movements of nonautistic adults as they completed the task. Using single trial analysis, we determined that the time between fixating and producing the homograph (eye-to-voice span) increased significantly across the experiment and predicted accuracy of homograph pronunciation, suggesting that participants adapted their reading strategy to minimize pronunciation errors. Additionally, we found evidence for interference from previous trials involving the same homograph. This progressively reduced the initial advantage for dominant homograph pronunciations as the experiment progressed. Our results identify several additional factors that contribute to performance on the homograph reading task and may help to reconcile the findings of poor performance on the test with contradictory findings from other studies using different measures of context sensitivity in autism. The results also undermine some of the broader theoretical inferences that have been drawn from studies of autism using the homograph task. Finally, we suggest that this approach to task deconstruction might have wider applications in experimental psychology.
No Deficiency in Left-to-Right Processing of Words in Dyslexia but Evidence for Enhanced Visual Crowding
Authors: Callens Maaike , Whitney Carol , Tops Wim , Brysbaert Marc
Published: January 2013

Whitney and Cornelissen hypothesized that dyslexia may be the result of problems with the left-to-right processing of words, particularly in the part of the word between the word beginning and the reader's fixation position. To test this hypothesis, we tachistoscopically presented consonant trigrams in the left and the right visual field (LVF, RVF) to 20 undergraduate students with dyslexia and 20 matched controls. The trigrams were presented at different locations (from –2.5° to + 2.5°) in both visual half fields. Participants were asked to identify the letters, and accuracy rates were compared. In line with the predictions of the SERIOL (sequential encoding regulated by inputs to oscillations within letter units) model of visual word recognition, a typical U-shaped pattern was found at all retinal locations. Accuracy also decreased the further away the stimulus was from the fixation location, with a steeper decrease in the LVF than in the RVF. Contrary to the hypothesis, the students with dyslexia showed the same pattern of results as did the control participants, also in the LVF, apart from a slightly lower accuracy rate, particularly for the central letter. The latter is in line with the possibility of enhanced crowding in dyslexia. In addition, in the dyslexia group but not in the control group the degree of crowding correlated significantly with the students’ word reading scores. These findings suggest that lateral inhibition between letters is associated with word reading performance in students with dyslexia.
Model prediction vs. reality—testing the predictions of a European eel (Anguilla anguilla) stock dynamics model against the in situ observation of silver eel escapement in compliance with the European eel regulation
Authors: Prigge E. , Marohn L. , Oeberst R. , Hanel R.
Published: January 2013

Prigge, E., Marohn, L., Oeberst R., and Hanel, R. 2013. Model prediction vs. reality—testing the predictions of a European eel (Anguilla anguilla) stock dynamics model against the in situ observation of silver eel escapement in compliance with the European eel regulation – ICES Journal of Marine Science, 70: 309–318. A direct monitoring of European silver eel (Anguilla anguilla, L) escapement from rivers and estuaries has been proven to be challenging, and a Europe-wide documentation of escaping silver eel numbers therefore hardly seems realistic. To reinforce management decisions, policy-makers are thus widely reliant on the accuracy of escapement models. A 3-year programme of silver eel escapement monitoring was undertaken to compile model input data and revise an eel population model (German Eel Model II; GEM II) already used in the decision-making process of management authorities. By compiling necessary input data and analysing vital system-specific population characteristics, it was possible to compare the documented silver eel escapement with the modelled potential silver eel escapement. Resulting model predictions were close to actually monitored escapement numbers, which were distinctly lower than reference escapement values for the same freshwater system given in the implementation report of the German Eel Management Plans. Applying different commercial and recreational catch scenarios revealed the sensitivity of the model. The results show the potential of the GEM II and highlight the importance of high-quality input data to use model predictions as the basis for management measures.
Cotton leaf curl disease – an emerging threat to cotton production worldwide
Authors: Sattar M. Naeem , Kvarnheden Anders , Saeed Muhammad , Briddon Rob W.
Published: January 2013

Cotton leaf curl disease (CLCuD) is a serious disease of cotton which has characteristic symptoms, the most unusual of which is the formation of leaf-like enations on the undersides of leaves. The disease is caused by whitefly-transmitted geminiviruses (family Geminiviridae, genus Begomovirus) in association with specific, symptom-modulating satellites (betasatellites) and an evolutionarily distinct group of satellite-like molecules known as alphasatellites. CLCuD occurs across Africa as well as in Pakistan and north-western India. Over the past 25 years, Pakistan and India have experienced two epidemics of the disease, the most recent of which involved a virus and satellite that are resistance breaking. Loss of this conventional host–plant resistance, which saved the cotton growers from ruin in the late 1990s, leaves farmers with only relatively poor host plant tolerance to counter the extensive losses the disease causes. There has always been the fear that CLCuD could spread from the relatively limited geographical range it encompasses at present to other cotton-growing areas of the world where, although the disease is not present, the environmental conditions are suitable for its establishment and the whitefly vector occurs. Unfortunately recent events have shown this fear to be well founded, with CLCuD making its first appearance in China. Here, we outline recent advances made in understanding the molecular biology of the components of the disease complex, their interactions with host plants, as well as efforts being made to control CLCuD.
The C terminus of NS5A domain II is a key determinant of hepatitis C virus genome replication, but is not required for virion assembly and release
Authors: Ross-Thriepland Douglas , Amako Yutaka , Harris Mark
Published: January 2013

The NS5A protein of hepatitis C virus (HCV) plays roles in both virus genome replication and the assembly of infectious virus particles. NS5A comprises three domains, separated by low-complexity sequences. Whilst the function of domain I appears to be predominantly involved with genome replication, the roles of domains II and III are less well defined. It has been reported previously that a deletion spanning the majority of domain II but retaining the C-terminal 35 residues had no effect on virus production; however, deletion of the entire domain II eliminated genome replication, pointing to a key role for the C terminus of this domain. Recent work has also highlighted this region as the potential binding site of the host factor cyclophilin A (CypA). To define this requirement for replication in more detail, and to investigate the involvement of CypA, we conducted a mutagenic study of the C-terminal 30 residues of domain II within the context of both the infectious JFH-1 virus and a JFH-1-derived subgenomic replicon. We showed that 12 of these residues were absolutely required for virus genome replication, whilst mutations of the remainder either had no phenotype or exhibited a partial reduction in genome replication. There was an absolute correlation between the datasets for virus and subgenomic replicon, indicating that this region is involved solely in the process of genome replication. Comparison of our data with a previously published analysis of the same region in genotype 1b revealed some important differences between the two genotypes of HCV.
“New leadership” and creating the high performance organisation: part 1
Authors: Coulson‐Thomas Colin
Published: January 2013

Purpose

In some respects traditional leadership is not working. The aim of this two‐part paper is to summarise key findings of a five year investigation into quicker and more affordable routes to creating high performance organisations. It identifies some aspects of the “new leadership” that is required and how the strategic adoption of performance support can facilitate the changes required and deliver multiple objectives. This first part introduces “new leadership” and performance support.

Design/methodology/approach

A programme of critical success factor, “issue” and other surveys was complemented with a five year evaluation of more recent case studies to understand early adoptions of performance support and to assess their results and implications. The applications examined were discussed with the relevant technical architect and the results obtained corroborated with commissioner/user performance data and/or documented assessments/reactions.

Findings

“New leadership” is less about “top‐down” leading and more about providing “bottom‐up” support, particularly of those who contribute to key corporate objectives. It requires a different balance and focus in a number of areas and can be facilitated by the strategic adoption of performance support which can deliver multiple benefits and offers a quicker and more affordable route to the high performance organisation.

Research limitations/implications

Further investigation is required of the implications of the findings for people and organisations.

Practical implications

A cheaper and more cost‐effective alternative to expensive, lengthy and disruptive change and transformation programmes has been demonstrated which can deliver essential elements of “new leadership”, boost performance, cut costs, reduce risks and stress, ensure compliance and generate high returns on investment. Despite its advantages the more widespread adoption of “new leadership” and performance support might require a re‐energising of corporate boards.

Social implications

There is potential for making difficult jobs easier and less stressful for many people.

Originality/value

The paper summarises the main findings of an investigation that has identified a requirement for “new leadership” and an approach which if strategically adopted can facilitate its introduction. Important aspects of the shift of emphasis and focus required by “new leadership” are identified, along with the central contribution that performance support can make to its beneficial adoption.
Employee training: ticking the box or building business competence?
Authors: Cadman Charlie
Published: January 2013

Purpose

The rise in regulatory requirements for health and safety skills certification over the past two decades prompted a tick box approach to training, with organisations simply undertaking the minimum requirements in order to maintain compliance. But the planned reduction in health and safety red tape combined with growing industry demand for proven skills from contractors and suppliers, as well as the cross skilling that has become so important during the on going economic downturn, is changing attitudes. The purpose of this paper is to explore this.

Design/methodology/approach

The paper includes a viewpoint and a case study.

Findings

Having learnt the value of up‐skilling staff in recent years to cope with a recessionary economy, organisations are now actively embracing the value of both company specific and industry standard training to build skills and demonstrate to customers a commitment to quality.

Originality/value

Ensuring employees have the right skills goes far beyond meeting regulatory obligations. As this article explains, there is a real opportunity to build strong, long term employee competency, minimise accidents and create the skills base that reflects the business needs of the organisation.
Five steps to a recession proof career
Authors: Reuter Jan
Published: January 2013

Purpose

Would you like to take control of your career so that you are not at the whim of the employer or the economy? The aim of this paper is to learn how to apply successful small business strategies to your career so that you are in charge.

Design/methodology/approach

Learn how to apply successful small business strategies to your career so that you are in charge. This article will help you to look at your career through the lens of an entrepreneur taking a product to market – in this case the product is you! The five steps include: assessing the strengths, capabilities and skills of your product; reviewing what the market wants; analysing the gaps between your product and what the market wants; planning the further development of your product; and marketing your product.

Findings

As of July 9 the author is launching a survey to gather success stories of how people have recession proofed their careers. However at the time of this writing the findings from that survey are not available.

Practical implications

These practical steps are easy to apply and can give your career the boost it needs in these uncertain economic times.

Originality/value

While many authors have given the advice to either treat your career as a business or to be the Chief Executive Officer of your career, “Five steps to a recession proof career” provides practical advice on how to actually achieve that goal.
Original editions of Chinese gazetteers in the Yale East Asia Library
Authors: Li Tang
Published: January 2013

Purpose

Chinese gazetteers are one of the most important primary sources for the study of history of Chinese economy, politics, culture, military, and science and technology. Since the very beginning, the Yale East Asia Library has been keen on collecting Chinese gazetteers. However, unlike its peer research libraries in the USA, the Yale East Asia Library had never compiled a catalog or written an article about its gazetteer collection. The purpose of this paper is to systematically review, for the first time, original editions of Chinese gazetteers held in the Yale East Asia Library to reveal the holdings and research value.

Design/methodology/approach

The author conducted a survey of original editions of Chinese gazetteers in the Yale East Asia Library by searching the Yale online library catalog and comparing with existing catalogs of Chinese local gazetteers compiled by other research libraries in the USA. The paper focuses on the edition, coverage, rarity and variety of Yale's holdings.

Findings

According to the author's findings and preliminary research, Yale holds approximately 337 original Chinese gazetteers. The majority of them is rarely found in other North American research libraries and thus has high research value. They cover almost all provinces and municipalities in China and have a great variety of types.

Research limitations/implications

Although the author tried to use various search strategies to look up in the Yale online library catalog to ensure high retrieval, the results here may not be accurate. Also it is likely that a number of Chinese gazetteers are not recorded in the Yale online library catalog because of backlogs. A physical survey of Chinese gazetteer holdings at Yale and more research need to be done in the future.

Originality/value

This paper is the first of its kind to provide a systematic review of original editions of Chinese gazetteers held in the Yale East Asia Library.
A directory to data on libraries and librarianship
Authors: Ondrusek Anita L.
Published: January 2013

Purpose

Electronically stored data on libraries, librarians, library users, and the information industry that supports library collections can assist librarians in projecting trends for the future directions of the profession. The purpose of this paper is to direct librarians to a selected list of providers of this data and their publications, particularly those sources that aggregate data in systematic, accessible formats.

Design/methodology/approach

Web sites of the organizations that collect data on libraries were examined for data reports generated either from research projects or from periodic reports.

Findings

There is a wealth of free data from ongoing research available on the web. In addition, there are proprietary data sets that librarians who need that specialized data should consider acquiring.

Research limitations/implications

LIS professionals require access to current and retrospective data to shape future research and inform decision making.

Originality/value

The article fills the need for an annotated directory to data sources specific to the needs of libraries and procurement information for those sources.