bluuebunny/crossref_metadata_2025 huggingface dataset:
Electronic structure of Fe/MgO/Fe multilayer stack by X-ray magnetic circular dichroism
Authors: Gautam Sanjeev , Asokan Kandasami , Pal Singh Jitendra , Chang Fan-Hsiu , Lin Hong-Ji , Hwa Chae Keun
Published: January 2014

The interface properties of Fe/MgO/Fe multilayer stack were investigated by using X-ray absorption spectroscopy (XAS) and X-ray magnetic circular dichroism (XMCD). The magnetic multilayers were deposited by electron beam evaporation method, which exhibits the attributes of perpendicular magnetic anisotropy (PMA). XAS analysis shows that Fe-layer forms a Fe-O-rich interface region with MgO-layer and a sum-rule analysis of the XMCD estimates the average magnetic moment of 2.31 ± 0.1 μB per Fe-atom. XAS and XMCD studies indicate the formation of a heterostructure (Fe/FeO/Fe2O3) on the interface. A phase transition in Fe-O stoichiometry at interface is also observed at low temperature (90 K), which may be useful in magnetic storage technology.
Crystal phases of soft spheres systems in a slab geometry
Authors: Antlanger Moritz , Doppelbauer Günther , Mazars Martial , Kahl Gerhard
Published: January 2014

We have identified the ground state configurations of soft particles (interacting via inverse power potentials) confined between two hard, impenetrable walls. To this end we have used a highly reliable optimization scheme at vanishing temperature while varying the wall separation over a representative range. Apart from the expected layered triangular and square structures (which are compatible with the three-dimensional bulk fcc lattice), we have identified a cascade of highly complex intermediate structures. Taking benefit of the general scaling properties of inverse power potentials, we could identify – for a given softness value – one single master curve which relates the energy to the wall separation, irrespective of the density of the system. Via extensive Monte Carlo simulations, we have performed closer investigations of these intermediate structures at finite temperature: we could provide evidence to which extent these particle arrangements remain stable over a relatively large temperature range.
In situ measurement of electrical resistivity and Seebeck coefficient simultaneously at high temperature and high pressure
Authors: Yuan Bao , Tao Qiang , Zhao Xueping , Cao Ke , Cui Tian , Wang Xin , Zhu Pinwen
Published: January 2014

A method for performing simultaneous measurements of the electrical resistivity and the Seebeck coefficient at high pressure and high temperature (HPHT) in cubic multi-anvil apparatus is described. For high pressure and high temperature measurements, a four-probe arrangement is used to measure the electrical resistivity and two pairs of chromel-alumel type thermocouples are employed to determine the Seebeck coefficient, respectively. Results of an expected temperature-induced phase transition, pressure-induced metallization and enhancement of the thermoelectric properties were obtained in Ag2Te. This method can provide the necessary data of thermoelectric materials at HPHT.
Pre-sheath density drop induced by ion-neutral friction along plasma blobs and implications for blob velocities
Authors: Furno I. , Theiler C. , Chabloz V. , Fasoli A. , Loizu J.
Published: January 2014

The pre-sheath density drop along the magnetic field in field-aligned, radially propagating plasma blobs is investigated in the TORPEX toroidal experiment [Fasoli et al., Plasma Phys. Controlled Fusion 52, 124020 (2010)]. Using Langmuir probes precisely aligned along the magnetic field, we measure the density nse at a poloidal limiter, where blobs are connected, and the upstream density n0 at a location half way to the other end of the blobs. The pre-sheath density drop nse/n0 is then computed and its dependence upon the neutral background gas pressure is studied. At low neutral gas pressures, the pre-sheath density drop is ≈0.4, close to the value of 0.5 expected in the collisionless case. In qualitative agreement with a simple model, this value decreases with increasing gas pressure. No significant dependence of the density drop upon the radial distance into the limiter shadow is observed. The effect of reduced blob density near the limiter on the blob radial velocity is measured and compared with predictions from a blob speed-versus-size scaling law [Theiler et al., Phys. Rev. Lett. 103, 065001 (2009)].
Differential geometry, Palatini gravity and reduction
Authors: Capriotti S.
Published: January 2014

The present article deals with a formulation of the so called (vacuum) Palatini gravity as a general variational principle. In order to accomplish this goal, some geometrical tools related to the geometry of the bundle of connections of the frame bundle LM are used. A generalization of Lagrange-Poincaré reduction scheme to these types of variational problems allows us to relate it with the Einstein-Hilbert variational problem. Relations with some other variational problems for gravity found in the literature are discussed.
Constrained, aqueous growth of three-dimensional single crystalline zinc oxide structures
Authors: Pooley Kathryn J. , Joo John H. , Hu Evelyn L.
Published: January 2014

We study low temperature (90 °C) aqueous growth of single crystal zinc oxide structures through patterned PMMA molds of different sizes, shapes, and orientations. We demonstrate the ability to create 3D shapes with smooth vertical sidewalls. Although the unconstrained growth is influenced by the hexagonal geometry of the underlying crystal structure, the ZnO is shown to conform exactly to any shape patterned. Using electron backscatter diffraction and scanning electron microscopy we show that the mold orientation, in conjunction with control of the growth rates of the c and m planes of the ZnO, is crucial in determining the final structure shape.
Half-metallicity and tetragonal distortion in semi-Heusler alloy FeCrSe
Authors: Huang H. M. , Luo S. J. , Yao K. L.
Published: January 2014

Full-potential linearized augmented plane wave methods are carried out to investigate the electronic structures and magnetic properties in semi-Heusler alloy FeCrSe. Results show that FeCrSe is half-metallic ferromagnet with the half-metallic gap 0.31 eV at equilibrium lattice constant. Calculated total magnetic moment of 2.00μB per formula unit follows the Slater-Pauling rule quite well. Two kinds of structural changes are used to investigate the sensitivity of half-metallicity. It is found that the half-metallicity can be retained when lattice constant is changed by −4.56% to 3.52%, and the results of tetragonal distortion indicate the half-metallicity can be kept at the range of c/a ratio from 0.85 to 1.20. The Curie temperature, cohesive energy, and heat of formations of FeCrSe are also discussed.
Growth mechanism and composition of ultrasmooth a-C:H:Si films grown from energetic ions for superlubricity
Authors: Chen Xinchun , Kato Takahisa
Published: January 2014

Growth mechanism and ion energy dependence of composition of ultrasmooth a-C:H:Si films grown from ionization of tetramethylsilane (TMS) and toluene mixture at a fixed gas ratio have been investigated by varying the applied bias voltage. The dynamic scaling theory is employed to evaluate the roughness evolution of a-C:H:Si films, and to extract roughness and growth exponents of α ∼ 0.51 and β ∼ 0, respectively. The atomically smooth surface of a-C:H:Si films with Ra ∼ 0.1 nm is thermally activated by the energetic ion-impact induced subsurface “polishing” process for ion dominated deposition. The ion energy (bias voltage) plays a paramount role in determining the hydrogen incorporation, bonding structure and final stoichiometry of a-C:H:Si films. The hydrogen content in the films measured by ERDA gradually decreases from 36.7 to 17.3 at. % with increasing the bias voltage from 0.25 to 3.5 kV, while the carbon content in the films increases correspondingly from 52.5 to 70.1 at. %. The Si content is kept almost constant at ∼9–10 at. %. Depending on the ion-surface interactions, the bonding structure of a-C:H:Si films grown in different ion energy regions evolves from chain-developed polymer-like to cross-linked diamond-like to sp2-bonded a–C as revealed by XPS, Raman, and FTIR analysis. Such a structural evolution is reflected in their measured nanomechanical properties such as hardness, modulus, and compressive stress. An enhanced viscoplastic behavior (i.e., viscoplastic exponent of ∼0.06) is observed for polymeric a-C:H:Si films. A hydrogen content threshold (H > 20 at. %) exists for the as-grown a-C:H:Si films to exhibit superlow friction in dry N2 atmosphere. An extremely low friction coefficient of ∼0.001 can be obtained for polymer-like a-C:H:Si film. These near-frictionless a-C:H:Si films are strongly promising for applications in industrial lubricating systems.
High-frequency magnetic properties of (FeCoNbB)-(SiO2) nanocolumnar films
Authors: Eguchi Tomoko , Nakagawa Naoyuki , Yonetsu Maki , Okamoto Keiko , Suetsuna Tomohiro , Suenaga Seiichi
Published: January 2014

(FeCo)-(SiO2) nanogranular films in which magnetic metal particles form nanosized columns, nanocolumnar, were studied. The nanostructure was formed by controlling the composition ratio of magnetic metal and insulating oxide. Inducing uniaxial anisotropy in the film plane resulted in high permeability in the GHz band and a high ferromagnetic resonance frequency. To improve the permeability loss factor, crystallinity of FeCo was controlled by adding B and Nb. As a result, an amorphous nanocolumnar film with ferromagnetic resonance frequency of greater than 5 GHz, high relative permeability of 44.9, and low loss factors of less than 1% up to 1 GHz was achieved.
The influence of field-free orientation on the predissociation dynamics of the NaI molecule
Authors: Zhao Ze-Yu , Han Yong-Chang , Yu Jie , Cong Shu-Lin
Published: January 2014

The orientation and predissociation dynamics of the NaI molecule are studied by using a time-dependent wavepacket method. The NaI molecule is first pre-oriented by a single-cycle pulse (SCP) in terahertz (THz) region and then predissociated by a femtosecond pump pulse. The influence of the molecular field-free orientation on the predissociation dynamics is studied in detail. We calculate the radial and angular distributions, the molecular orientation degrees, and the time-dependent populations for both the ground and excited electronic states. It is found that the pre-orientation affects the angular distributions significantly, and that it has weak influence on the radial distributions. By varying the delay time between the THz SCP and the pump pulse, the angular distribution of the fragments from the predissociation can be manipulated.
Modified InGaN/GaN quantum wells with dual-wavelength green-yellow emission
Authors: Fang Z. L. , Li Q. F. , Shen X. Y. , Xiong H. , Cai J. F. , Kang J. Y. , Shen W. Z.
Published: January 2014

Energy band engineering by indium pretreatment of the bottom GaN barriers and control of the growth temperature profile for the InGaN active layers were employed to improve the green-yellow emitting InGaN/GaN quantum well (QW). The modified InGaN/GaN QWs were investigated by various characterization techniques and demonstrated to be of good interface abruptness and well-defined indium concentration profile, composed of 0.52 nm In0.35Ga0.65N “wetting layer,” 1.56 nm In0.35-0.22Ga0.65-0.78N graded layers, and 1.56 nm In0.22Ga0.78N layer along the growth direction. Broad-band dual-wavelength green-yellow emission at about 497 and 568 nm was observed and attributed to the major contribution of enhanced interband transitions from the first and second quantized electron states “e1” and “e2” to the first quantized hole state “h1.” With the modified QW structure, electron overflow loss would be suppressed by filling of the excited electron state with electrons at high carrier injection density and reduction in polarization-induced band bending. APSYS simulation shows efficiency and droop improvements due to the enhanced overlapping of electron and hole wave functions inside the modified InGaN active layers, and the enhanced interband transitions involving the excited electron state.
Solution processable interface materials for nanoparticulate organic photovoltaic devices
Authors: Nicolaidis Nicolas , Vaughan Ben , Mulligan Cara J. , Bryant Glenn , Zillger Tino , Trnovec Bystrik , Hübler Arved C. , Holmes Natalie , Cooling Nathan A. , Griffith Matthew J. , Bilen Chhinder , Kumar Pankaj , Feron Krishna , Zhou Xiaojing , Elkington Daniel , Belcher Warwick J. , Dastoor Paul C.
Published: January 2014

Nanoparticulate zinc oxide can be prepared at low temperatures from solution processable zinc acetylacetonate. The use of this material as a cathode interfacial layer in nanoparticulate organic photovoltaic devices results in comparable performances to those based on reactive calcium layers. Importantly, the enhanced degradation stability and full solution processability make zinc oxide a more desirable material for the fabrication of large area printed devices.
Investigation of Pt/Pb(Zr0.2Ti0.8)O3/Ti-Al-O/Si heterostructure as metal/ferroelectric/insulator/semiconductor
Authors: Fu Y. J. , Fu G. S. , Li M. , Jia D. M. , Jia Y. L. , Liu B. T.
Published: January 2014

Pt/Pb(Zr0.2Ti0.8)O3(PZT)/Ti-Al-O(TAO)/Si heterostructure has been fabricated as the metal/ferroelectric/insulator/semiconductor structure. It is found that PZT film is polycrystalline, and TAO film is amorphous. Moreover, the memory windows are 3.4 V, 5.9 V, 8.6 V, and 11.2 V corresponding, respectively, to the voltages of 10 V, 12 V, 14 V, and 16 V, indicating that the memory window increases linearly with the increase of applied voltage, which can be attributed to the increase of the polarization and coercive voltage of the Pb(Zr0.2Ti0.8)O3 film. The leakage current density of the device, measured at 15 V, is 3.54 × 10−6 A/cm2, is favorable for the device application.
The multiferroic properties of polycrystalline Bi1−xYxFeO3 films
Authors: Sheng Yan , Rui Wenbin , Qiu Xiangbiao , Du Jun , Zhou Shengqiang , Xu Qingyu
Published: January 2014

Polycrystalline Bi1−xYxFeO3 films with varying x from 0 to 0.30 were prepared by pulsed laser deposition on surface oxidized Si (100) substrates with LaNiO3 as buffer layer. The influence of Y doping on the structure, ferroelectric properties, and exchange bias have been systematically investigated. X-ray diffraction and Raman spectroscopy studies revealed the structural transition from rhombohedral R3c to orthorhombic Pn21a with increasing x above 0.10. The leakage current density of BiFeO3 has been effectively suppressed by Y doping, and well saturated P–E loops have been observed in Bi1−xYxFeO3 (0.01 ≤ x ≤ 0.07). Exchange bias field with a 3.6 nm thick NiFe layer increases with increasing x to 0.01, then decreases with further increasing x.
Intense photoluminescence from dried double-stranded DNA and single-walled carbon nanotube hybrid
Authors: Ito M. , Kobayashi T. , Ito Y. , Hayashida T. , Nii D. , Umemura K. , Homma Y.
Published: January 2014

Semiconducting single-walled carbon nanotubes (SWNTs) show near-infrared photoluminescence (PL) when they are individually isolated. This was an obstacle to use photonic properties of SWNTs on a solid surface. We show that SWNTs wrapped with DNA maintain intense PL under the dry conditions. SWNTs are well isolated individually by DNA even when the DNA-SWNT hybrids are agglomerated. This finding opens up application of SWNTs to photonic devices.
Routes to spatiotemporal chaos in Kerr optical frequency combs
Authors: Coillet Aurélien , Chembo Yanne K.
Published: January 2014

We investigate the various routes to spatiotemporal chaos in Kerr optical frequency combs, obtained through pumping an ultra-high Q-factor whispering-gallery mode resonator with a continuous-wave laser. The Lugiato–Lefever model is used to build bifurcation diagrams with regards to the parameters that are externally controllable, namely, the frequency and the power of the pumping laser. We show that the spatiotemporal chaos emerging from Turing patterns and solitons display distinctive dynamical features. Experimental spectra of chaotic Kerr combs are also presented for both cases, in excellent agreement with theoretical spectra.
Exchange bias and antiferromagnetic interfacial exchange coupling in the mixed-spin oxide Li2/7Ni5/7O
Authors: Shi C. X. , Ren W. J. , Liu W. , Zhang Z. D.
Published: January 2014

We present a detailed study on magnetic properties of mixed spin oxide Li2/7Ni5/7O, where small ferromagnetic (FM) clusters (with averaged diameter of ∼18 Å) immersed with an antiferromagnetic (AFM) host. The exchange bias (EB) with shifts of the hysteresis loop along both the field and magnetization axes is found, which is due to the interfacial interaction between the FM clusters and the AFM host. An AFM interfacial exchange coupling is deduced from the exchange interactions between Ni ions. The type and strength of this interfacial exchange interaction are discussed in terms of the EB at low temperature.
Glass transition and crystallization kinetics of a barium borosilicate glass by a non-isothermal method
Authors: Lopes Andreia A. S. , Soares Roque S. , Lima Maria M. A. , Monteiro Regina C. C.
Published: January 2014

The glass transition and crystallization kinetics of a glass with a molar composition 60BaO-30B2O3-10SiO2 were investigated by differential scanning calorimetry (DSC) under non-isothermal conditions. DSC curves exhibited an endothermic peak associated with the glass transition and two partially overlapped exothermic peaks associated with the crystallization of the glass. The dependence of the glass transition temperature (Tg) and of the maximum crystallization temperature (Tp) on the heating rate was used to determine the activation energy associated with the glass transition (Eg), the activation energy for crystallization (Ec), and the Avrami exponent (n). X-ray diffraction (XRD) revealed that barium borate (β-BaB2O4) was the first crystalline phase to be formed followed by the formation of barium silicate (Ba5Si8O21). The variations of activation energy for crystallization and of Avrami exponent with the fraction of crystallization (χ) were also examined. When the crystallization fraction (χ) increased from 0.1 to 0.9, the value of local activation energy (Ec(χ)) decreased from 554 to 458 kJ/mol for the first exothermic peak and from 1104 to 831 kJ/mol for the second exothermic peak. The value determined for the Avrami exponent was near 2 indicating a similar one-dimensional crystallization mechanism for both crystalline phases. This was confirmed by the morphological studies performed by scanning electron microscopy (SEM) on glass samples heat-treated at the first and at the second crystallization temperatures.
Anomalous patterns and nearly defect-free ripples produced by bombarding silicon and germanium with a beam of gold ions
Authors: Mollick Safiul Alam , Ghose Debabrata , Shipman Patrick D. , Mark Bradley R.
Published: January 2014

We demonstrate that surface ripples with an exceptionally high degree of order can develop when germanium is bombarded with a broad beam of gold ions. In contrast, if silicon is sputtered with an Au− beam, patches of ripples with two distinct wave vectors can emerge. These types of order can be understood if the coupling between the surface morphology and composition is taken into account.
MoC intermediate layer for FePt magnetic recording media
Authors: Tsai Jai-Lin , Luo Qi-Shao , Chen Po-Ran , Chen Yi-Hsiu
Published: January 2014

A (001) textured FePt film was deposited on MoC/CrRu/glass at a substrate temperature of 380 °C by using magnetron sputtering. The MoC conductive intermediate layer was used to resist the Cr diffusion up to high deposition temperatures and promotes the epitaxial growth of the (001) textured FePt film. The FePt film showed high perpendicular magnetization and the out-of-plane coercivity increased with MoC thickness. The FePt/MoC (5 nm)/CrRu film showed a square out-of-plane magnetic hysteresis loop with a coercivity of 6.0 kOe and a linear-like in-plane loop. A multi-functional MoC intermediate layer exhibited heteroepitaxial relation with FePt and CrRu and was capable of resisting the interlayer diffusion at high deposition temperatures.
Geometric phases and quantum correlations dynamics in spin-boson model
Authors: Wu Wei , Xu Jing-Bo
Published: January 2014

We explore the dynamics of spin-boson model for the Ohmic bath by employing the master equation approach and obtain an explicit expression of reduced density matrix. We also calculate the geometric phases of the spin-boson model by making use of the analytical results and discuss how the dissipative bosonic environment affects geometric phases. Furthermore, we investigate the dynamics of quantum discord and entanglement of two qubits each locally interacting with its own independent bosonic environments. It is found that the decay properties of quantum discord and entanglement are sensitive to the choice of initial state's parameter and coupling strength between system and bath.
Temperature dependent near infrared ultraviolet range dielectric functions of nanocrystalline (Na0.5Bi0.5)1−xCex(Ti0.99Fe0.01)O3 films
Authors: Zhang S. , Zhang J. Z. , Han M. J. , Li Y. W. , G. Hu Z. , Chu J. H.
Published: January 2014

Optical properties and phase transition of Ce-modified (Na0.5Bi0.5)(Ti0.99Fe0.01)O3 nanocrystalline films have been investigated by spectroscopic ellipsometry from −70 to 500 °C. Temperature dependent dielectric functions in the photon energy range of 0.6–6.4 eV can be derived by the Tauc-Lorentz model. It was found that the features in dielectric function (ε) showed an abrupt variation near 200 and 340 °C, respectively. The phenomena can be explained by the appearance and/or reversal of polarization. It indicates that ferroelectric (rhombohedral) to paraelectric (tetragonal) phase transition is related to electronic band variation, which is observed by this technique.
Polarization field engineering of GaN/AlN/AlGaN superlattices for enhanced thermoelectric properties
Authors: Sztein Alexander , Bowers John E. , DenBaars Steven P. , Nakamura Shuji
Published: January 2014

A novel polarization field engineering based strategy to simultaneously achieve high electrical conductivity and low thermal conductivity in thermoelectric materials is demonstrated. Polarization based electric fields are used to confine electrons into two-dimensional electron gases in GaN/AlN/Al0.2Ga0.8N superlattices, resulting in improved electron mobilities as high as 1176 cm2/Vs and in-plane thermal conductivity as low as 8.9 W/mK. The resulting room temperature ZT values reach 0.08, a factor of four higher than InGaN and twelve higher than GaN, demonstrating the potential benefits of this polarization based engineering strategy for improving the ZT and efficiencies of thermoelectric materials.
Suppression of slow capacitance relaxation phenomenon in Pt/Ba0.3Sr0.7TiO3/Pt thin film ferroelectric structures by annealing in oxygen atmosphere
Authors: Altynnikov A. G. , Gagarin A. G. , Gaidukov M. M. , Tumarkin A. V. , Petrov P. K. , Alford N. , Kozyrev A. B.
Published: January 2014

The impact of oxygen annealing on the switching time of ferroelectric thin film capacitor structures Pt/Ba0.3Sr0.7TiO3/Pt was investigated. The response of their capacitance on pulsed control voltages before and after annealing was experimentally measured. It was demonstrated that the annealing results in suppression of the capacitance slow relaxation processes and increase of the threshold control voltages. These structures can therefore be attractive for fabrication of fast acting microwave devices.
Enhanced catalyst-free nucleation of GaN nanowires on amorphous Al2O3 by plasma-assisted molecular beam epitaxy
Authors: Sobanska Marta , Klosek Kamil , Borysiuk Jolanta , Kret Slawomir , Tchutchulasvili Giorgi , Gieraltowska Sylwia , Zytkiewicz Zbigniew R.
Published: January 2014

We report on plasma-assisted molecular beam epitaxial growth of GaN nanowires (NWs) on Si(111) substrates with a thin amorphous Al2O3 buffer layer deposited by atomic layer deposition. Comparison of nucleation kinetics shows that presence of amorphous Al2O3 buffer significantly enhances spontaneous nucleation of GaN NWs. Slower nucleation was observed on partially amorphous silicon nitride films. No growth of NWs was found on sapphire substrate under the same growth conditions which we explain by a low density of defects on monocrystalline substrate surface where NWs may nucleate. Our finding shows that tuning of substrate microstructure is an efficient tool to control rate of self-induced nucleation of GaN NWs.
The effects of deep level traps on the electrical properties of semi-insulating CdZnTe
Authors: Zha Gangqiang , Yang Jian , Xu Lingyan , Feng Tao , Wang Ning , Jie Wanqi
Published: January 2014

Deep level traps have considerable effects on the electrical properties and radiation detection performance of high resistivity CdZnTe. A deep-trap model for high resistivity CdZnTe was proposed in this paper. The high resistivity mechanism and the electrical properties were analyzed based on this model. High resistivity CdZnTe with high trap ionization energy Et can withstand high bias voltages. The leakage current is dependent on both the deep traps and the shallow impurities. The performance of a CdZnTe radiation detector will deteriorate at low temperatures, and the way in which sub-bandgap light excitation could improve the low temperature performance can be explained using the deep trap model.
The economic benefits of providing shelter to reduce the mortality of twin lambs in south-western Victoria
Authors: Young J. M. , Saul G. , Behrendt R. , Byrne F. , McCaskill M. , Kearney G. A. , Thompson A. N.
Published: January 2014

Achieving higher lamb weaning percentages by reducing lamb mortality can improve the profitability of sheep enterprises. In this paper we estimated the financial benefits from providing shelter to reduce the mortality of twin lambs in self-replacing Merino or dual-purpose Merino flock enterprises in south-west Victoria. A whole-farm bio-economic model (MIDAS) was initially used to estimate the increase in profit from reducing mortality of twin lambs and a second analysis included the costs of using perennial grass hedges to provide the shelter during lambing. The economic value of providing shelter was tested at three rates of twinning (10, 30 and 50%), three rates of mortality without shelter (70, 50 and 30%) and two levels of reduction in lamb mortality by providing shelter (25 and 50% reduction). A sensitivity analysis to wool and lamb prices, costs of establishing the grass hedges and stocking rates in the shelter area were also tested. Overall, more than 2500 scenarios were tested. Across the range of twinning rates and levels of twin mortality tested, at standard wool and meat prices, providing shelter to the dual-purpose Merino ewe flock was always profitable ($0.05 to 11.35/ewe) and the profits from providing shelter to the self-replacing Merino ewe flock were generally lower ($0.15 to $6.35/ewe). The impacts of changing wool and lamb prices depended on enterprise type, whereas the costs of establishment of the hedges or stocking rate of ewes in the hedge area during lambing had little impact on profitability. The main factor that determined the economic return from shelter was the reduction in mortality provided by the shelter but the proportion of twin-bearing ewes in the flock and the base rate of lamb mortality without shelter was also important. Overall, based on the assumptions used, we conclude that the profitability of many sheep enterprises lambing during frequent high chill weather conditions in temperate areas of south-eastern Australia could be improved by providing low cost shelter for twin-bearing Merino ewes lambing from July to September.
Effects of different concentrations of ground oak acorn on growth performance, blood parameters and carcass characteristics of goat kids
Authors: Froutan E. , Azizi O. , Sadeghi G. , Fatehi F. , Lashkari S.
Published: January 2014

The objective of the present study was to evaluate the effect of different levels of ground oak acorn on growth performance, blood parameters and carcass characteristics. Twenty-four goat kids averaging 16.93 ± 1.25 kg initial bodyweight were randomly assigned to four experimental diets in a completely randomised design for 90 days. The experimental diets consisted of (1) 0% oak acorn (control), (2) 8% oak acorn, (3) 17% oak acorn and (4) 25% oak acorn on a DM basis. The goats were slaughtered after 105 days of feeding and carcass characteristics were measured. DM intake increased linearly in small amounts as the level of acorn in the diet increased (P < 0.004). The results showed that average daily gain, water intake and feed conversion ratio were unaffected by levels of ground oak acorn (P > 0.05). There were no significant differences in blood parameters (P > 0.05). Carcass fat depth and abdominal fat weight decreased with increasing ground oak acorn in the diet. Other carcass characteristics were not affected by different levels of ground oak acorn. On the basis of the results of the present study, it may be concluded that ground oak acorn can be used up to 25% in the diets of young goats without any adverse effects on growth performance and carcass characteristics. At this level of acorns, the goats received low concentrations of hydrolysable tannins (11 g/kg DM) in their diet.
FSH and LH receptors are differentially expressed in cumulus cells surrounding developmentally competent and incompetent mouse fully grown antral oocytes
Authors: Vigone Giulia , Merico Valeria , Redi Carlo Alberto , Mazzini Giuliano , Garagna Silvia , Zuccotti Maurizio
Published: January 2014

Cumulus cells (CCs) maintain strict functional relationships with the enclosed antral oocyte and are thought to reflect its developmental competence. Several studies have described a correlation between CC gene expression and oocyte quality. Herein, we tested whether CC-specific FSH and LH receptors (FSHR and LHR, respectively) are differentially expressed in CCs enclosing developmentally competent or incompetent oocytes. To this end, mouse fully grown cumulus–oocyte complexes were isolated and their CCs and oocytes analysed separately. Based on their chromatin organisation, oocytes were classified as those with a surrounded nucleolus (SN) or a non-surrounded nucleolus (NSN), the former being developmentally competent, whereas the latter arrest at the 2-cell stage. The CCs were then analysed to compare the pattern of expression of the Fshr and Lhr genes and their proteins. Quantitative reverse transcription–polymerase chain reaction analysis revealed that only Lhr is significantly differentially expressed. Immunofluorescence analysis revealed that both FSHR and LHR proteins are significantly upregulated in CCs surrounding oocytes arrested at the 2-cell stage, reflecting their developmental incompetence.
Slow recruitment in a red-fox population following poison baiting: a non-invasive mark–recapture analysis
Authors: Berry Oliver , Tatler Jack , Hamilton Neil , Hilmer Steffi , Hitchen Yvette , Algar Dave
Published: January 2014

Context
Optimal management of invasive species should determine the interval between lethal-control operations that will sustain a desired population suppression at minimum cost. This requires an understanding of the species’ rate of recruitment following control. These data are difficult to acquire for vertebrate carnivores such as the red fox (Vulpes vulpes), which are not readily trapped or observed.

Aims
To provide a long-term evaluation of the effects of 1080 poison baiting on the abundance and extent of movement of red foxes in a semiarid environment.

Methods
We used non‐invasive DNA sampling of fox hairs in semi-arid Western Australia where the population was subject to two episodes of aerially delivered sodium fluoroacetate (1080) poison baits within 12 months. Sampling took place at ~45-day intervals and individual foxes were identified by genotyping eight microsatellite DNA markers and a gender-specific marker. Open-population and spatially explicit mark–recapture models were used to estimate the density, apparent survival and movements of foxes before and following baiting.

Key results
Following a severe reduction in density after baiting, fox density during the ensuing 12 months increased slowly (0.01 foxes km–2 month–1), such that density had only reached 22% of pre-baiting levels ~10 months after the initial baiting. Moreover, recovery was non‐linear as population growth was negligible for 6 months, then exhibited a nine-fold increase 7–9 months after control, coincident with the dispersal of juveniles in autumn. Fox movements between recaptures were on average 470% greater after baiting than before, in line with expectations for low-density populations, suggesting that the probability of encountering baits during this period would be higher than before baiting.

Conclusions
Baiting with 1080 poison significantly reduced the density of foxes, and the low density was sustained for more than 6 months. Foxes moved significantly further between recaptures after baiting when at low densities.

Implications
Control programs in this region may be carried out at low frequency to suppress fox density to a fraction of unbaited levels. The intensity of follow-up baiting may also be adjusted downwards, to take account of an increased probability of bait encounter in more mobile foxes.
IFN-γ signaling maintains skin pigmentation homeostasis through regulation of melanosome maturation
Authors: Natarajan Vivek T. , Ganju Parul , Singh Archana , Vijayan Vinaya , Kirty Kritika , Yadav Shalini , Puntambekar Shraddha , Bajaj Sonali , Dani Prachi P. , Kar Hemanta K. , Gadgil Chetan J. , Natarajan Krishnamurthy , Rani Rajni , Gokhale Rajesh S.
Published: January 2014

Significance

Skin tanning is a protective response of epidermal cells involving increased melanin formation. Overexposure to sun can cause sunburn and even skin cancer, and such conditions are partly attributable to the accumulation of toxic side products of melanin and its intermediates. In this study, we reveal the importance of key immune cytokine IFN-γ in pigmentation biology by studying cultured human melanocyte cells as well as mice and human disease models. We show that IFN-γ signaling regulates enzymes involved in melanin biosynthesis through a transcription factor IFN regulatory factor-1. Our study identifies a new mechanism of skin pigmentation homeostasis and proposes that strength and durability of local skin immune response may be decisive factors to delineate outcome between skin tanning and cancer.
Remote loading of preencapsulated drugs into stealth liposomes
Authors: Sur Surojit , Fries Anja C. , Kinzler Kenneth W. , Zhou Shibin , Vogelstein Bert
Published: January 2014

Significance

Nanoliposomal packaging of chemotherapeutics can increase efficacy while reducing toxicity, but its use is currently limited due to inefficient loading strategies. We developed an active loading procedure by designing a transient chemical handle for ferrying such agents into preformed liposomes. We illustrate its use with two candidates that recently failed phase II studies. We were able to load both these drugs into liposomes with high efficiency and administer them to animals at substantially higher doses than previously possible, thereby simultaneously enhancing efficacy and reducing toxicity. This strategy should be applicable to many agents that are currently being developed to treat cancer or other diseases, and can “rescue” drugs that would otherwise fail at the final stages of the drug discovery process.
Antimicrobial Stewardship Program to Reduce Antiretroviral Medication Errors in Hospitalized Patients with Human Immunodeficiency Virus Infection
Authors: Sanders Jamie , Pallotta Andrea , Bauer Seth , Sekeres Jennifer , Davis Ramona , Taege Alan , Neuner Elizabeth
Published: January 2014

Objective.

Evaluate antimicrobial stewardship interventions targeted to reduce highly active antiretroviral therapy (HAART)– or opportunistic infection (Ol)–related medication errors and increase error resolution.

Design.

Retrospective before-after study.

Setting.

Academic medical center.

Patients.

Inpatients who were prescribed antiretroviral therapy before the intervention (January 1, 2011, to October 31, 2011) and after the intervention (July 1, 2012, to December 31, 2012). Patients treated with lamivudine or tenofovir monotherapy for hepatitis B were excluded.

Methods.

Antimicrobial stewardship interventions included education, modification of electronic medication records, collaboration with the infectious diseases (ID) department, and prospective audit and review of HAART and OI regimens by an ID clinical pharmacist.

Results.

Data for 162 admissions from the preintervention period and 110 admissions from the postintervention period were included. The number of admissions with a medication error was significantly reduced after the intervention (81 [50%] of 162 admissions vs 37 (34%) of 110 admissions; P < .00)1. A total of 124 errors occurred in the preintervention group (mean no. of errors, 1.5 per admission), and 43 errors occurred in the postintervention group (mean no. of errors, 1.2 per admission). The most common error types were major drug interactions and dosing in the preintervention group and renal adjustment and OI-related errors in the postintervention group. A significantly higher error resolution rate was observed in the postintervention group (36% vs 74%; P < .001). After adjustment for potential confounders with logistic regression, admission in the postintervention group was independently associated with fewer medication errors (odds ratio, 0.4 [95% confidence interval, 0.24-0.77]; P = .005). Overall, presence of an ID consultant demonstrated a higher error resolution rate (32% without a consultation vs 68% with a consultation; P = .002).

Conclusions.

Multifaceted, multidisciplinary stewardship efforts reduced the rate and increased the overall resolution of HAART-related medication errors.
Activity of Commonly Used Antimicrobial Prophylaxis Regimens against Pathogens Causing Coronary Artery Bypass Graft and Arthroplasty Surgical Site Infections in the United States, 2006–2009
Authors: Berríos-Torres Sandra I. , Yi Sarah H. , Bratzler Dale W. , Ma Allen , Mu Yi , Zhu Liping , Jernigan John A.
Published: January 2014

Background.

Coronary artery bypass graft (CABG) and primary arthroplasty surgical site infection (SSI) rates are declining slower than other healthcare-associated infection rates. We examined antimicrobial prophylaxis (AMP) regimens used for these operations and compared their spectrum of activity against reported SSI pathogens.

Methods.

Pathogen distributions of CABG and hip/knee arthroplasty complex SSIs (deep and organ/space) reported to the National Healthcare Safety Network (NHSN) from 2006 through 2009 and AMP regimens (same procedures and time period) reported to the Surgical Care Improvement Project (SCIP) were analyzed. Regimens were categorized as standard (cefazolin or cefuroxime),β-lactam allergy (vancomycin or clindamycin with or without an aminoglycoside), and extended spectrum (vancomycin and/or an aminoglycoside with cefazolin or cefuroxime). AMP activity of each regimen was predicted on the basis of pathogen susceptibility reports and published spectra of antimicrobial activity.

Results.

There were 6,263 CABG and arthroplasty complex SSIs reported (680,489 procedures; 880 NHSN hospitals). Among 6,574 pathogens reported, methicillin-sensitiveStaphylococcus aureus(23%), methicillin-resistantS. aureus(18%), coagulase-negative staphylococci (17%), andEnterococcusspecies (7%) were most common. AMP regimens for 2,435,703 CABG and arthroplasty procedures from 3,330 SCIP hospitals were analyzed. The proportion of pathogens predictably susceptible to standard (used in 75% of procedures),β-lactam (12%), and extended-spectrum (8%) regimens was 41%–45%, 47%–96%, and 81%—96%, respectively.

Conclusion.

Standard AMP, used in three-quarters of CABG and primary arthroplasty procedures, has inadequate activity against more than half of SSI pathogens reported. Alternative strategies may be needed to prevent SSIs caused by pathogens resistant to standard AMP regimens.
Survey of North Carolina Hospital Policies Regarding Visitor Use of Personal Protective Equipment for Entering the Rooms of Patients under Isolation Precautions
Authors: Kang JaHyun , Weber David J. , Mark Barbara A. , Rutala William A.
Published: January 2014

Objective.

To explore the range of hospital policies for visitor use of personal protective equipment (PPE) when entering the room of patients under isolation precautions.

Design.

Survey using an online questionnaire.

Setting.

Acute care hospitals registered in the North Carolina Statewide Program for Infection Control and Epidemiology (SPICE).

Methods.

A total of 136 North Carolina hospitals were invited to participate in an online survey. The survey questionnaire was developed, reviewed, and pilot tested, and then it was distributed through SPICE listserv registered e-mail addresses. The survey was conducted from February 6 to March 30, 2012.

Results.

Among 93 respondent hospitals (response rate, 68.4%), 82 acute care hospitals (60.3%) were included in the analyses. Substantial variation was observed with regard to hospital policies for visitor PPE use when visiting patients under isolation precautions. A total of 71% of hospitals had a hospital visitor policy, and 96% of respondents agreed that hospitals should have a visitor policy. Only 14% of hospitals monitored visitor compliance with PPE. Reported compliance rates varied from “very low” to 97%. Many hospitals (28%) reported difficulties related to visitor compliance with isolation precautions, including hostility and refusal to comply.

Conclusions.

Our study results illuminated hospital policy variations for visitor isolation precautions. Reported problems with hospital visitor policies (eg, different policies across departments or facilities) suggest the need for standard guidelines and for enhanced public awareness about the importance of visitor compliance with isolation precautions.
On joint numerical radius
Authors: Müller Vladimir
Published: January 2014

Let

T
1

,
…
,

T
n

T_1,\dots ,T_n

be bounded linear operators on a complex Hilbert space

H
H

. We study the question whether it is possible to find a unit vector

x
∈
H

x\in H

such that

|

⟨

T
j

x
,
x
⟩

|

|\langle T_jx,x\rangle |

is large for all

j
j

. Thus we are looking for a generalization of a well-known fact for

n
=
1

n=1

that the numerical radius

w
(
T
)

w(T)

of a single operator

T
T

satisfies

w
(
T
)
≥
‖
T
‖

/

2

w(T)\ge \|T\|/2

.
Absence of eigenvalues of non-selfadjoint Schrödinger operators on the boundary of their numerical range
Authors: Hansmann Marcel
Published: January 2014

We use a classical result of Hildebrandt to establish simple conditions for the absence of eigenvalues of non-selfadjoint discrete and continuous Schrödinger operators on the boundary of their numerical range.
Gevrey hypoellipticity for sums of squares with a non-homogeneous degeneracy
Authors: Bove Antonio , Tartakoff David
Published: January 2014

In this paper we consider sums of squares of vector fields in

R

2

\mathbb {R}^2

satisfying Hörmander’s condition and with polynomial, but non-(quasi-)homoge- neous, coefficients. We obtain a Gevrey hypoellipticity index which we believe to be sharp. The general operator we consider is
\[

P
=

X
2

+

Y
2

+

∑

j
=
1

L

Z
j
2

,

P=X^2+Y^2+\sum _{j=1}^{L}Z_j^2,

\]
with
\[
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="upper X equals upper D Subscript x Baseline comma upper Y equals a 0 left-parenthesis x comma y right-parenthesis x Superscript q minus 1 Baseline upper D Subscript y Baseline comma upper Z Subscript j Baseline equals a Subscript j Baseline left-parenthesis x comma y right-parenthesis x Superscript p Super Subscript j Superscript minus 1 Baseline y Superscript k Super Subscript j Superscript Baseline upper D Subscript y Baseline comma">

X
=

D
x

,

Y
=

a

0

(
x
,
y
)

x

q
−
1

D
y

,

Z
j

=

a

j

(
x
,
y
)

x

p
j

−
1

y

k
j

D
y

,

X=D_x, \quad Y= a_{0}(x, y) x^{q-1}{D_y}, \quad Z_j= a_{j}(x, y) x^{p_j-1}y^{k_j}\,D_y,

\]
with

a

j

(
0
,
0
)
≠
0

a_{j}(0, 0) \neq 0

,

j
=
0
,
1
,
…
,
L

j = 0, 1, \ldots , L

and

q
>

p
j

,
{

k
j

}

q>p_j, \{k_j\}

arbitrary. The theorem we prove is that

P
P

is Gevrey-s hypoelliptic for

s
≥

1

1
−
T

,
T
=

max
j

q
−

p
j

q

k
j

.

s\geq \frac {1}{1-T}, T = \max _j \frac {q-p_j}{q k_j}.
Herp coordinates compartmentalization and recruitment of HRD1 and misfolded proteins for ERAD
Authors: Leitman Julia , Shenkman Marina , Gofman Yana , Shtern Navit Ogen , Ben-Tal Nir , Hendershot Linda M. , Lederkremer Gerardo Z.
Published: January 2014

A functional unfolded protein response (UPR) is essential for endoplasmic reticulum (ER)-associated degradation (ERAD) of misfolded secretory proteins, reflecting the fact that some level of UPR activation must exist under normal physiological conditions. A coordinator of the UPR and ERAD processes has long been sought. We previously showed that the PKR-like, ER-localized eukaryotic translation initiation factor 2α kinase branch of the UPR is required for the recruitment of misfolded proteins and the ubiquitin ligase HRD1 to the ER-derived quality control compartment (ERQC), a staging ground for ERAD. Here we show that homocysteine-induced ER protein (Herp), a protein highly upregulated by this UPR branch, is responsible for this compartmentalization. Herp localizes to the ERQC, and our results suggest that it recruits HRD1, which targets to ERAD the substrate presented by the OS-9 lectin at the ERQC. Predicted overall structural similarity of Herp to the ubiquitin-proteasome shuttle hHR23, but including a transmembrane hairpin, suggests that Herp may function as a hub for membrane association of ERAD machinery components, a key organizer of the ERAD complex.
Minfi: a flexible and comprehensive Bioconductor package for the analysis of Infinium DNA methylation microarrays
Authors: Aryee Martin J. , Jaffe Andrew E. , Corrada-Bravo Hector , Ladd-Acosta Christine , Feinberg Andrew P. , Hansen Kasper D. , Irizarry Rafael A.
Published: January 2014

Motivation: The recently released Infinium HumanMethylation450 array (the ‘450k’ array) provides a high-throughput assay to quantify DNA methylation (DNAm) at ∼450 000 loci across a range of genomic features. Although less comprehensive than high-throughput sequencing-based techniques, this product is more cost-effective and promises to be the most widely used DNAm high-throughput measurement technology over the next several years.

Results: Here we describe a suite of computational tools that incorporate state-of-the-art statistical techniques for the analysis of DNAm data. The software is structured to easily adapt to future versions of the technology. We include methods for preprocessing, quality assessment and detection of differentially methylated regions from the kilobase to the megabase scale. We show how our software provides a powerful and flexible development platform for future methods. We also illustrate how our methods empower the technology to make discoveries previously thought to be possible only with sequencing-based methods.

Availability and implementation:  http://bioconductor.org/packages/release/bioc/html/minfi.html.

Contact:  khansen@jhsph.edu; rafa@jimmy.harvard.edu

Supplementary information:  Supplementary data are available at Bioinformatics online.