bluuebunny/crossref_metadata_2025 huggingface dataset:
IUPAC-NIST Solubility Data Series. 101. Alcohols + Hydrocarbons + Water. Part 1. C4–C10 Alcohols
Authors: Góral Marian , Shaw David G. , Mączyński Andrzej , Wiśniewska-Gocłowska Barbara , Oracz Paweł
Published: April 2014

Reports of experimental determinations of solubility for 30 ternary systems of C4–C10 alcohols with hydrocarbons and water are exhaustively compiled and critically evaluated. Reports of experimental determination of solubility that appeared in the primary literature prior to the middle of 2012 are included. For seven systems, sufficient data (two or more independent desterminations) for critical evaluation are available. All data are expressed as mass percent and mole fraction as well as the originally reported units. In addition to the standard evaluation criteria used throughout the Solubility Data Series, two additional criteria were used for each of the evaluated systems. These systems include two binary miscibility gaps in the alcohol + water and hydrocarbon + water subsystems. The binary tie lines were compared with the recommended values published previously and with values obtained with a predictive NRTL model.
Effects of Cr substitution on structural and magnetic properties in La0.7Pr0.3Fe11.4Si1.6 compound
Authors: Md Din M. F. , Wang J. L. , Studer A. J. , Gu Q. F , Zeng R. , Debnath J. C , Shamba P. , Kennedy S. J. , Dou S. X.
Published: April 2014

In an effort to explore the effect of substitution Fe by Cr in NaZn13-type La0.7Pr0.3Fe11.4−xCrxSi1.6 (x = 0, 0.06, 0.12, 0.26, and 0.34) compounds, the structure and magnetic properties have been investigated by high intensity of x-ray and neutron diffraction, scanning electron microscopy, specific heat, and magnetization measurement. It has been found that a substitution of Cr for Fe in this compounds leads to decrease in the lattice parameter a at room temperature but variation on Curie temperature (TC). While the first order nature of magnetic phase transition around TC does not change with increasing Cr content up to x = 0.34. High intensity x-ray and neutron diffraction study at variable temperatures for highest Cr concentration x = 0.34 confirmed the presence of strong magneto-volume effect around TC and indicated the direct evident of coexistence across magnetic transition as characteristic of first order nature. The values of −ΔSM around TC decrease from 17 J kg−1 K−1 for x = 0 to 12 J kg−1 K−1 for x = 0.06 and then increases with further increasing Cr content up to 17.5 J kg−1 K−1 for x = 0.34 under a change of 0–5 T magnetic field. Similar behavior on relative cooling power which is decrease from 390 J kg−1 for x = 0 to 365 J kg−1 for x = 0.06 at the beginning and then increases up to 400 J kg−1 for x = 0.34. From the point of this view with the highest Cr concentration (x = 0.34) exhibits favourable material candidate for magnetic refrigerator application therefore should inspire further study concerning on higher Cr concentration in this compound.
Skew angle effects in shingled magnetic recording system with double/triple reader head array
Authors: Elidrissi Moulay Rachid , Sann Chan Kheong , Greaves Simon , Kanai Yasushi , Muraoka Hiroaki
Published: April 2014

Shingled Magnetic Recording (SMR) is a scheme used to extend the life of the current perpendicular magnetic recording technology. SMR enables writing narrow tracks with a wide writer. Currently, SMR employs a single reader and will suffer inter-track interference (ITI) as the tracks become comparable in width to the reader. ITI can be mitigated by using narrower readers; however, narrower readers suffer from increased reader noise. Another approach to combat ITI is to process 2D readback and use ITI cancellation schemes to retrieve the data track. Multiple readbacks can be obtained either with a single reader and multiple revolutions or with a reader array. The former suffers from increased readback latency. In this work, we focus on the latter. When using a reader array, the skew angle poses major challenges. During writing, there is increased adjacent track erasure, and during readback the effective reader pitch varies and there is an increase in the 2D intersymbol interference caused by the rotated reader profile. In this work, we run micromagnetic simulations at different skew angles to train the grain flipping probability model, and then evaluate raw bit channel error rate performance at skew. In particular, we investigate the performance degradation caused by skewing of the 2 or 3 read head array for various read-head geometries.
Structure and OH-stretch spectroscopy of low- and high-density amorphous ices
Authors: Tainter C. J. , Shi L. , Skinner J. L.
Published: April 2014

We use the E3B water simulation model (which explicitly includes three-body interactions) and molecular dynamics simulations to study the structure of low- and high-density amorphous ices. We find that the “interstitial” molecule in high-density amorphous ice, which is responsible for the higher density, is not hydrogen bonded to the central molecule or its nearest neighbors. This molecule enforces a wider range of local environments as demonstrated by the tetrahedral order parameter, whereas the local structure of low-density amorphous ice is more ordered. We also present theoretical vibrational spectra (infrared, Raman, and two-dimensional infrared) for the amorphous phases, for both HOD/D2O and H2O. The results are in qualitative agreement with experiment and reflect the fact that low-density amorphous ice is more ordered, with stronger hydrogen bonds, compared to high-density amorphous ice. For both the structural analysis and spectral calculations, we compare the results for the amorphous ices with those for crystalline ice Ih and supercooled water.
Lift forces in granular media
Authors: Guillard François , Forterre Yoël , Pouliquen Olivier
Published: April 2014

The paper presents an experimental and numerical study of the forces experienced by a cylinder moving horizontally in a granular medium under gravity. Despite the symmetry of the object, a strong lift force is measured. Whereas the drag force increases linearly with depth, the lift force is shown to saturate at depths much greater than the cylinder diameter, and to scale like the buoyancy with a large amplification factor of order 20. The origin of this high lift force is discussed based on the stress distribution measured in discrete numerical simulations. The lift force comes from the gravitational pressure gradient, which breaks the up/down symmetry and strongly modifies the flow around the obstacle compared to the case without pressure gradient.
A seamless acquisition digital storage oscilloscope with three-dimensional waveform display
Authors: Yang Kuojun , Tian Shulin , Zeng Hao , Qiu Lei , Guo Lianping
Published: April 2014

In traditional digital storage oscilloscope (DSO), sampled data need to be processed after each acquisition. During data processing, the acquisition is stopped and oscilloscope is blind to the input signal. Thus, this duration is called dead time. With the rapid development of modern electronic systems, the effect of infrequent events becomes significant. To capture these occasional events in shorter time, dead time in traditional DSO that causes the loss of measured signal needs to be reduced or even eliminated. In this paper, a seamless acquisition oscilloscope without dead time is proposed. In this oscilloscope, three-dimensional waveform mapping (TWM) technique, which converts sampled data to displayed waveform, is proposed. With this technique, not only the process speed is improved, but also the probability information of waveform is displayed with different brightness. Thus, a three-dimensional waveform is shown to the user. To reduce processing time further, parallel TWM which processes several sampled points simultaneously, and dual-port random access memory based pipelining technique which can process one sampling point in one clock period are proposed. Furthermore, two DDR3 (Double-Data-Rate Three Synchronous Dynamic Random Access Memory) are used for storing sampled data alternately, thus the acquisition can continue during data processing. Therefore, the dead time of DSO is eliminated. In addition, a double-pulse test method is adopted to test the waveform capturing rate (WCR) of the oscilloscope and a combined pulse test method is employed to evaluate the oscilloscope's capture ability comprehensively. The experiment results show that the WCR of the designed oscilloscope is 6 250 000 wfms/s (waveforms per second), the highest value in all existing oscilloscopes. The testing results also prove that there is no dead time in our oscilloscope, thus realizing the seamless acquisition.
A compact fast ionization gauge for in situ measurement of high-density neutral flow dynamics
Authors: Weber T. E. , Intrator T. P.
Published: April 2014

A compact ionization gauge has been developed to carry out in situ measurements of high density (1020–1022 m−3) neutral gas flow dynamics with high temporal and spatial resolution. Key design aspects are discussed including gauge sensitivity and time response scaling with decreased probe dimensions, high-pressure operation, improved driver circuit bandwidth, and techniques for constructing a miniaturized probe head. Gas adsorption was discovered to significantly alter emission current and gauge sensitivity over timescales of several seconds. This effect must be taken into consideration when making time-resolved, high-density measurements. Over short timescales gauge response was predicted by scaling the sensitivity of a nominal Bayard-Alpert gauge to account for variations in probe dimensions and species-dependent ionization cross-section. Time-resolved neutral density profiles have been acquired in the Magnetized Shock Experiment at Los Alamos National Laboratory, providing data on the initial conditions of the ionization, plasmoid formation, and translation processes. It is shown that the desired density profiles can be achieved using a dynamic gas fill and that density can be scaled independently of the spatial profile.
Quantum diffraction effects on the atomic polarization collision in partially ionized dense plasmas
Authors: Jung Young-Dae
Published: April 2014

The influence of quantum diffraction on the electron-atom polarization collision process is investigated in partially ionized dense plasmas. The pseudopotential model and eikonal method are employed to obtain the eikonal phase shift and eikonal cross section as functions of the impact parameter, collision energy, Debye length, electron de Broglie wavelength, and atomic polarizability. The results show that the eikonal phase shift for the electron-hydrogen atom polarization collision decreases with an increase of the electron de Broglie wavelength. It is important to note that the influence of quantum diffraction produces the repulsive part in the electron-atom polarization interaction. It is also found that the quantum diffraction effect enhances the differential eikonal cross section. Additionally, the total eikonal cross section decreases with increasing electron de Broglie wavelength. The variations of the eikonal cross section due to the influence of finite size of the de Broglie wavelength and Debye radius are also discussed.
Note: A piezo tip/tilt platform: Structure, kinematics, and experiments
Authors: Du Z. , Su Y. , Yang W. , Dong W.
Published: April 2014

A Piezo Tip/Tilt Platform (PT2P) is presented with its structure, kinematics, and preliminary experiments. Two essential models of the presented PT2P, an equivalent hinge of the flexure hinge and a simplified model of the transmission mechanism, are discussed with the analysis on the structure of the PT2P. Based on these models, the inverse kinematics of the PT2P is derived. Two experiments are conducted on a prototype of the PT2P. The kinematic model is verified with experimental results, which also indicate that the resolution and the repeatability of the PT2P is, respectively, better than 0.50 μrad and 0.25 μrad.
Communication: Nucleation of quantized vortex rings in 4He nanodroplets
Authors: Mateo David , Leal Antonio , Hernando Alberto , Barranco Manuel , Pi Martí , Cargnoni Fausto , Mella Massimo , Zhang Xiaohang , Drabbels Marcel
Published: April 2014

Whereas most of the phenomena associated with superfluidity have been observed in finite-size helium systems, the nucleation of quantized vortices has proven elusive. Here we show using time-dependent density functional simulations that the solvation of a Ba+ ion created by photoionization of neutral Ba at the surface of a 4He nanodroplet leads to the nucleation of a quantized ring vortex. The vortex is nucleated on a 10 ps timescale at the equator of a solid-like solvation structure that forms around the Ba+ ion. The process is expected to be quite general and very efficient under standard experimental conditions.
Interface trap density and mobility extraction in InGaAs buried quantum well metal-oxide-semiconductor field-effect-transistors by gated Hall method
Authors: Chidambaram Thenappan , Veksler Dmitry , Madisetti Shailesh , Greene Andrew , Yakimov Michael , Tokranov Vadim , Hill Richard , Oktyabrsky Serge
Published: April 2014

In this work, we are using a gated Hall method for measurement of free carrier density and electron mobility in buried InGaAs quantum well metal-oxide-semiconductor field-effect-transistor channels. At room temperature, mobility over 8000 cm2/Vs is observed at ∼1.4 × 1012 cm−2. Temperature dependence of the electron mobility gives the evidence that remote Coulomb scattering dominates at electron density <2 × 1011 cm−2. Spectrum of the interface/border traps is quantified from comparison of Hall data with capacitance-voltage measurements or electrostatic modeling. Above the threshold voltage, gate control is strongly limited by fast traps that cannot be distinguished from free channel carriers just by capacitance-based methods and can be the reason for significant overestimation of channel density and underestimation of carrier mobility from transistor measurements.
Partially coherent twisted states in arrays of coupled phase oscillators
Authors: Omel'chenko Oleh E. , Wolfrum Matthias , Laing Carlo R.
Published: April 2014

We consider a one-dimensional array of phase oscillators with non-local coupling and a Lorentzian distribution of natural frequencies. The primary objects of interest are partially coherent states that are uniformly “twisted” in space. To analyze these, we take the continuum limit, perform an Ott/Antonsen reduction, integrate over the natural frequencies, and study the resulting spatio-temporal system on an unbounded domain. We show that these twisted states and their stability can be calculated explicitly. We find that stable twisted states with different wave numbers appear for increasing coupling strength in the well-known Eckhaus scenario. Simulations of finite arrays of oscillators show good agreement with results of the analysis of the infinite system.
Note: Laser beam scanning using a ferroelectric liquid crystal spatial light modulator
Authors: Das Abhijit , Boruah Bosanta R.
Published: April 2014

In this work we describe laser beam scanning using a ferroelectric liquid crystal spatial light modulator. Commercially available ferroelectric liquid crystal spatial light modulators are capable of displaying 85 colored images in 1 s using a time dithering technique. Each colored image, in fact, comprises 24 single bit (black and white) images displayed sequentially. We have used each single bit image to write a binary phase hologram. For a collimated laser beam incident on the hologram, one of the diffracted beams can be made to travel along a user defined direction. We have constructed a beam scanner employing the above arrangement and demonstrated its use to scan a single laser beam in a laser scanning optical sectioning microscope setup.
Effect of antiferromagnetic layer thickness on exchange bias, training effect, and magnetotransport properties in ferromagnetic/antiferromagnetic antidot arrays
Authors: Gong W. J. , Liu W. , Feng J. N. , Kim D. S. , Choi C. J. , Zhang Z. D.
Published: April 2014

The effect of antiferromagnetic (AFM) layer on exchange bias (EB), training effect, and magnetotransport properties in ferromagnetic (FM) /AFM nanoscale antidot arrays and sheet films Ag(10 nm)/Co(8 nm)/NiO(tNiO)/Ag(5 nm) at 10 K is studied. The AFM layer thickness dependence of the EB field shows a peak at tNiO = 2 nm that is explained by using the random field model. The misalignment of magnetic moments in the three-dimensional antidot arrays causes smaller decrease of EB field compared with that in the sheet films for training effect. The anomalous magnetotransport properties, in particular positive magnetoresistance (MR) for antidot arrays but negative MR for sheet films are found. The training effect and magnetotransport properties are strongly affected by the three-dimensional spin-alignment effects in the antidot arrays.
Role of secondary emission on discharge dynamics in an atmospheric pressure dielectric barrier discharge
Authors: Tay W. H. , Kausik S. S. , Yap S. L. , Wong C. S.
Published: April 2014

The discharge dynamics in an atmospheric pressure dielectric barrier discharge (DBD) is studied in a DBD reactor consisting of a pair of stainless steel parallel plate electrodes. The DBD discharge has been generated by a 50 Hz ac high voltage power source. The high-speed intensified charge coupled device camera is used to capture the images of filaments occurring in the discharge gap. It is observed that frequent synchronous breakdown of micro discharges occurs across the discharge gap in the case of negative current pulse. The experimental results reveal that secondary emissions from the dielectric surface play a key role in the synchronous breakdown of plasma filaments.
Magnetic phases in NiO and MnO ultrathin films: Finite thickness and strain effects
Authors: León H. , Riera R.
Published: April 2014

Magnetic phases of NiO and MnO ultrathin films are established on the basis of a Hamiltonian including superexchange and dipolar interaction, disregarding the magnetocrystalline interaction because of its considerably smaller contribution in these films. The employed theoretical approach demonstrates that the finite thickness is substantially more important than the strain effect on the stabilization of the ground state configurations. An antiferromagnetic phase where ferromagnetic layers are piled up with alternating opposite in-plane orientations of the spins appears in NiO and MnO (111) ultrathin films, while a striped antiferromagnetic phase with the larger component of the magnetic moments along the growth direction is found in NiO and MnO (001) ultrathin films. These results are in qualitative agreement with available experimental results, but they disagree with the ones of a former theory, which is carefully examined.
Revision of the Coulomb logarithm in the ideal plasma
Authors: Mulser P. , Alber G. , Murakami M.
Published: April 2014

The standard picture of the Coulomb logarithm in the ideal plasma is controversial, the arguments for the lower cut off need revision. The two cases of far subthermal and of far superthermal electron drift motions are accessible to a rigorous analytical treatment. We show that the lower cut off bmin is a function of symmetry and shape of the shielding cloud, it is not universal. In the subthermal case, shielding is spherical and bmin is to be identified with the de Broglie wavelength; at superthermal drift the shielding cloud exhibits cylindrical (axial) symmetry and bmin is the classical parameter of perpendicular deflection. In both situations, the cut offs are determined by the electron-ion encounters at large collision parameters. This is in net contrast to the governing standard interpretation that attributes bmin to the Coulomb singularity at vanishing collision parameters b and, consequently, assigns it universal validity. The origin of the contradictions in the traditional picture is analyzed.
Magnetic domain control and voltage response of exchange biased magnetoelectric composites
Authors: Lage E. , Urs N. O. , Röbisch V. , Teliban I. , Knöchel R. , Meyners D. , McCord J. , Quandt E.
Published: April 2014

Self-biased magnetoelectric composites, which are realized with the exchange bias effect, hold an increased total anisotropy field compared to systems without exchange bias. Thus, small exchange bias fields are favorable because of a minor reduction of magnetic permeability and magneto-electric voltage coefficient. However, weakly biased magnetoelectric composites lose their self-biasing properties and possibly show an increase of discontinuities in magnetization reversal due to the formation of magnetic domains. By a thickness variation of the ferromagnetic layer, a maximum voltage coefficient αME ≈ 430 V/cm Oe was found for a magnetostrictive multilayer of 3 × (5 nm Ta/3 nm Cu/8 nm Mn-Ir/333 nm Fe-Co-Si-B). Yet, a stable single domain state indicating a well defined magnetization reversal by coherent magnetization rotation was achieved for layer thicknesses up to 100 nm Fe-Co-Si-B with αME ≈ 340 V/cm Oe. This slight reduction is overcompensated by the improved control of the magnetic domain pattern which is highly beneficial for magnetic field sensing applications and of special importance, when frequency conversion techniques are applied.
Current-voltage spectroscopy of dopant-induced quantum-dots in heavily n-doped junctionless nanowire transistors
Authors: Wang Hao , Han Weihua , Ma Liuhong , Li Xiaoming , Hong Wenting , Yang Fuhua
Published: April 2014

We demonstrate current-voltage spectroscopy of dopant-induced quantum dots in heavily n-doped junctionless nanowire transistors (JNTs) at low temperatures. The similar multiple-split current peak features for both single-channel and multiple-channel JNTs are found at the initial stage of conduction below the temperature of 75 K. The temperature stability of the pinch-off voltage, affected by activated electrons from defects and donor ionization, has been effectively improved by the 20 nm-width nanowires. The transition temperature for single electron tunneling to thermal activated transport is dependent on the ionization energy of dopants.
Determining Curie temperatures in dilute ferromagnetic semiconductors: High Curie temperature (Ga,Mn)As
Authors: Wang M. , Marshall R. A. , Edmonds K. W. , Rushforth A. W. , Campion R. P. , Gallagher B. L.
Published: April 2014

In this paper, we use simultaneous magnetometry and electrical transport measurements to critically examine ways in which the Curie temperature (TC) values have been determined in studies of dilute magnetic semiconductors. We show that, in sufficiently homogeneous samples, TC can be accurately determined from remanent magnetization and magnetic susceptibility and from the positions of the peak in the temperature derivative of the resistivity. We also show that the peak of the resistivity does not occur at TC, as illustrated by a (Ga,Mn)As sample for which the peak of the resistivity is at 213 ± 1 K when TC is only 178 ± 1 K.
Mechanism of high dielectric performance of polymer composites induced by BaTiO3-supporting Ag hybrid fillers
Authors: Fang Fang , Yang Wenhu , Yu Shuhui , Luo Suibin , Sun Rong
Published: April 2014

BaTiO3-supporting Ag hybrid particles (BT-Ag) with varied fraction of Ag were synthesized by reducing silver nitrate in the glycol solution containing BaTiO3 (BT) suspensions. The Ag nano particles with a size of about 20 nm were discretely grown on the surface of the BT. The dielectric performance of the composites containing the BT-Ag as fillers in the matrix of polyvinylidene fluoride (PVDF) was investigated. The relative permittivity (εr) of the BT-Ag/PVDF composites increased prominently with the increase of BT-Ag loading amount, and the typical conductive path of the conductor/polymer system was not observed even with a high loading of BT-Ag. The εr at 100 Hz for the three BT-(0.31, 0.49, 0.61)Ag/PVDF composites at room temperature were 283, 350, and 783, respectively. The εr of the composites was enhanced by more than 3 times compared with that of the composite containing untreated BT nanoparticles at frequencies over 1 kHz and the loss tangent (tan δ) was less than 0.1 which should be attributed to the low conductivity of the composites. Theoretical calculations based on the effective medium percolation theory model and series-parallel model suggested that the enhanced permittivity of BT-Ag/PVDF composites should arise from the ultrahigh permittivity of BT-Ag fillers, which was over 104 and associated with the content of Ag deposited on the surface of BT.
Note: Equation of state and the freezing point in the hard-sphere model
Authors: Robles Miguel , López de Haro Mariano , Santos Andrés
Published: April 2014

The merits of different analytical equations of state for the hard-sphere system with respect to the recently computed high-accuracy value of the freezing-point packing fraction are assessed. It is found that the Carnahan–Starling–Kolafa and the branch-point approximant equations of state yield the best performance.
Phase transitions in delafossite CuLaO2 at high pressures
Authors: Salke Nilesh P. , Garg Alka B. , Rao Rekha , Achary S. N. , Gupta M. K. , Mittal R. , Tyagi A. K.
Published: April 2014

Structural stability of a transparent conducting oxide CuLaO2 at high pressures is investigated using in-situ Raman spectroscopy, electrical resistance, and x-ray diffraction techniques. The present Raman investigations indicate a sequence of structural phase transitions at 1.8 GPa and 7 GPa. The compound remains in the first high pressure phase when pressure is released. Electrical resistance measurements carried out at high pressures confirm the second phase transition. These observations are further supported by powder x-ray diffraction at high pressures which also showed that a-axis is more compressible than c-axis in this compound. Fitting the pressure dependence of unit cell volume to 3rd order Birch-Murnaghan equation of state, zero pressure bulk modulus of CuLaO2 is determined to be 154(25) GPa. The vibrational properties in the ambient delafossite phase of CuLaO2 are investigated using ab-initio calculations of phonon frequencies to complement the Raman spectroscopic measurements. Temperature dependence of the Raman modes of CuLaO2 is investigated to estimate the anharmonicity of Raman modes.
Initial and secondary oxidation products on the Si(111)-(7 × 7) surface identified by atomic force microscopy and first principles calculations
Authors: Onoda Jo , Ondráček Martin , Yurtsever Ayhan , Jelínek Pavel , Sugimoto Yoshiaki
Published: April 2014

We investigate the initial and secondary oxidation products on the Si(111)-(7 × 7) surface at room-temperature using atomic force microscopy (AFM) and density functional theory calculations. At the initial oxidation stages, we find that there are two types of bright spots in AFM images. One of them is identified as a Si adatom with one O atom inserted into one of the backbonds, while the other is ascribed to a Si adatom with two inserted O atoms. We observe that the latter one turns into the secondary oxidation product by a further coming O2 molecule, which appears as a more protruded bright spot. The atomic configuration of this product is identified as Si adatom whose top and all three backbonds make bonds with O atoms. The appearances of initial and secondary oxidation products are imaged as bright and dark sites by scanning tunneling microscopy, respectively. It is revealed that AFM gives us the topographic information close to the real atomic corrugation of adsorbed structures on the semiconductor surfaces.
Magnetically coupled electromagnetically induced transparency analogy of dielectric metamaterial
Authors: Zhang Fuli , Zhao Qian , Lan Chuwen , He Xuan , Zhang Weihong , Zhou Ji , Qiu Kepeng
Published: April 2014

In this manuscript, we experimentally demonstrate magnetically coupled electromagnetically induced transparency (EIT) analogy effect inside dielectric metamaterial. In contrast to previous studies employed different metallic topological microstructures to introduce dissipation loss change, barium strontium titanate, and calcium titanate (CaTiO3) are chosen as the bright and dark EIT resonators, respectively, due to their different intrinsic dielectric loss. Under incident magnetic field excitation, dielectric metamaterial exhibits an EIT-type transparency window around 8.9 GHz, which is accompanied by abrupt change of transmission phase. Numerical calculations show good agreement with experiment spectra and reveal remarkably increased group index, indicating potential application in slow light.
A low thermal impact annealing process for SiO2-embedded Si nanocrystals with optimized interface quality
Authors: Hiller Daniel , Gutsch Sebastian , Hartel Andreas M. , Löper Philipp , Gebel Thoralf , Zacharias Margit
Published: April 2014

Silicon nanocrystals (Si NCs) for 3rd generation photovoltaics or optoelectronic applications can be produced by several industrially compatible physical or chemical vapor deposition technologies. A major obstacle for the integration into a fabrication process is the typical annealing to form and crystallize these Si quantum dots (QDs) which involves temperatures ≥1100  °C for 1 h. This standard annealing procedure allows for interface qualities that correspond to more than 95% dangling bond defect free Si NCs. We study the possibilities to use rapid thermal annealing (RTA) and flash lamp annealing to crystallize the Si QDs within seconds or milliseconds at high temperatures. The Si NC interface of such samples exhibits huge dangling bond defect densities which makes them inapplicable for photovoltaics or optoelectronics. However, if the RTA high temperature annealing is combined with a medium temperature inert gas post-annealing and a H2 passivation, luminescent Si NC fractions of up to 90% can be achieved with a significantly reduced thermal load. A new figure or merit, the relative dopant diffusion length, is introduced as a measure for the impact of a Si NC annealing procedure on doping profiles of device structures.
Prenatal exposure to testosterone masculinises the female gerbil and promotes the development of lesions in the prostate (Skene’s gland)
Authors: Biancardi Manoel F. , Perez Ana P. S. , Caires Cássia Regina Suzuki , Góes Rejane M. , Vilamaior Patrícia S. L. , Santos Fernanda C. A. , Taboga Sebastião R.
Published: April 2014

Androgenic imbalance may disrupt prostate development, leading to morphological alterations in adulthood and predisposing this gland to develop diseases during ageing. However, little is known about the endocrine disruption of the prostate that is caused by androgenic compounds, especially in female experimental models. Therefore, this study aimed to evaluate the prostates of aged female gerbils exposed to testosterone at certain periods in intrauterine and postnatal life, to determine whether exposure at a particular age increases susceptibility to prostatic lesions in these animals. To this end, morphological, stereological, immunohistochemical and immunofluorescence analyses were employed. It was found that females exposed to testosterone during intrauterine life were masculinised, showing increased anogenital distance, absence of the vaginal opening and ectopic development of prostatic tissue. Several areas of adenomatous hyperplasia, generally associated with inflammatory foci and mainly located in the ectopic prostatic tissue around the vaginal wall, were also observed. In conclusion, the results showed that abnormal prenatal exposure to testosterone severely affects the reproductive systems of female animals by disrupting normal prostate morphogenesis and increasing susceptibility to the development of prostatic diseases during ageing.
Biologically-active laminin-111 fragment that modulates the epithelial-to-mesenchymal transition in embryonic stem cells
Authors: Horejs Christine-Maria , Serio Andrea , Purvis Alan , Gormley Adam J. , Bertazzo Sergio , Poliniewicz Anna , Wang Alex J. , DiMaggio Peter , Hohenester Erhard , Stevens Molly M.
Published: April 2014

Significance

Laminin-111 is one of the first extracellular matrix proteins expressed during embryogenesis and has been studied for decades, mainly because of its major role in assembling the basement membrane, but also because it has now become one of the most popular cell culture substrates for embryonic stem cells. However, considering the importance of this protein, the role laminin-111 plays during matrix remodeling—which is not only of great interest when seeking to understand cell–matrix interactions, but also when using laminin as a substrate for tissue engineering—is still unclear. Our findings propose a previously unidentified role of laminin-111 that goes beyond basement membrane assembly and an important involvement in the regulation of the epithelial-to-mesenchymal transition.
Breastfeeding and Methadone Therapy: The Maternal Experience
Authors: Demirci Jill R. , Bogen Debra L. , Klionsky Yael
Published: April 2014

Background

Despite evidence of low transfer of methadone into breast milk and the potential physical and psychological benefits that breastfeeding offers for methadone-exposed mothers and infants, the rate of breastfeeding initiation in this population is about half that reported nationally. This study describes the perceptions surrounding breastfeeding decisions and management among pregnant and postpartum women taking methadone.

Methods

Seven pregnant women and 4 postpartum women enrolled in methadone maintenance programs participated in semistructured, audiotaped interviews and focus groups, respectively, about their breastfeeding experiences. Transcripts were analyzed and coded using qualitative content analysis.

Results

Three major content categories were identified: (1) fears, barriers, and misconceptions about breastfeeding while taking methadone; (2) motivation and perceived benefits of breastfeeding; and (3) sources of information, support, and anxiety about general breastfeeding management and breastfeeding while taking methadone. Lack of support from the health care community and misinformation about the dangers of combining breastfeeding and methadone therapy represented significant, yet modifiable, barriers to breastfeeding success in methadone-exposed women.

Conclusions

Interventions to increase the prevalence of breastfeeding among women taking methadone should address identified logistical, educational, and psychological barriers and consider inclusion of women themselves, partners, peers, and clinicians. In particular, clinicians who care for methadone-exposed mothers and infants should be educated on therapeutic communication, up-to-date breastfeeding contraindications, and the health benefits of breastfeeding in this population.
Buprenorphine Treatment for Probationers and Parolees
Authors: Gordon Michael S. , Kinlock Timothy W. , Schwartz Robert P. , Couvillion Kathryn A. , Sudec Laura J. , O'Grady Kevin E. , Vocci Frank J. , Shabazz Hamin
Published: April 2014

Background

Pharmacotherapy studies involving buprenorphine have rarely been conducted with US community corrections populations. This is one of the first reports of buprenorphine treatment outcomes of adult opioid-dependent probationers and parolees.

Methods

This longitudinal study examined the 3-month treatment outcomes for a sample of probation and parole clients ( N = 64) who received community-based buprenorphine treatment.

Results

Approximately two thirds of the sample (67%) were still in treatment at 3 months post baseline. Furthermore, there was a significant decline in the number of self-reported heroin use days and crime days from baseline to 3 months post baseline. Although there was not a significant reduction in reincarcerations, there was no evidence that they had increased.

Conclusions

Given that buprenorphine is approved by the Food and Drug Administration (FDA) as a safe, effective treatment for opioid use disorders, individuals on parole or probation should have the opportunity to benefit from it through community-based programs.
Fast alignment-free sequence comparison using spaced-word frequencies
Authors: Leimeister Chris-Andre , Boden Marcus , Horwege Sebastian , Lindner Sebastian , Morgenstern Burkhard
Published: April 2014

Motivation: Alignment-free methods for sequence comparison are increasingly used for genome analysis and phylogeny reconstruction; they circumvent various difficulties of traditional alignment-based approaches. In particular, alignment-free methods are much faster than pairwise or multiple alignments. They are, however, less accurate than methods based on sequence alignment. Most alignment-free approaches work by comparing the word composition of sequences. A well-known problem with these methods is that neighbouring word matches are far from independent.

Results: To reduce the statistical dependency between adjacent word matches, we propose to use ‘spaced words’, defined by patterns of ‘match’ and ‘don’t care’ positions, for alignment-free sequence comparison. We describe a fast implementation of this approach using recursive hashing and bit operations, and we show that further improvements can be achieved by using multiple patterns instead of single patterns. To evaluate our approach, we use spaced-word frequencies as a basis for fast phylogeny reconstruction. Using real-world and simulated sequence data, we demonstrate that our multiple-pattern approach produces better phylogenies than approaches relying on contiguous words.

Availability and implementation: Our program is freely available at http://spaced.gobics.de/.

Contact:  chris.leimeister@stud.uni-goettingen.de

Supplementary information:  Supplementary data are available at Bioinformatics online.
Heresy, Law and the State: Forfeiture in Late Medieval and Early Modern England
Authors: Cavill P.R.
Published: April 2014

As a punishment for heresy, forfeiture of property had originated in Roman law, was decreed by canon law, and applied across late medieval Europe. English ecclesiastical and secular legislation of the early fifteenth century formally adopted confiscation in response to the threat of Lollardy. Prompted by Oldcastle’s rising, in 1414 an Act of Parliament ordered that heretics should henceforth suffer the penalty of felony forfeiture. This identification of heresy with criminality justified greater lay involvement in the suppression of religious dissent. Because heresy was designated as a type of felony, the Crown claimed offenders’ personal possessions and lords their real property; the Church had no right to heretics’ estates. Although the Act provided the common-law basis for forfeiture, the penalty was imposed in other circumstances that paralleled practice outside England. Notwithstanding the Richard Hunne affair, forfeiture for heresy generated little controversy during the break with Rome. Legislation in the 1530s, in fact, extended the use of forfeiture as a punishment for religious dissent. The Act of 1414 was repealed under Edward VI, revived under Mary I, and again repealed under Elizabeth I. Following this second repeal in 1559, forfeiture lapsed as a penalty for heresy. The association between heresy and crime was thus loosened.
Identification of the progenitors of rich clusters and member galaxies in rapid formation at z > 2
Authors: Shimakawa Rhythm , Kodama Tadayuki , Tadaki Ken-ichi , Tanaka Ichi , Hayashi Masao , Koyama Yusei
Published: April 2014

We present the results of near-infrared spectroscopy of Hα emitters (HAEs) associated with two protoclusters around radio galaxies (PKS 1138−262 at z = 2.2 and USS 1558−003 at z = 2.5) with the Multi-Object Infrared Camera and Spectrograph (MOIRCS) on the Subaru telescope. Among the HAE candidates constructed from our narrow-band imaging, we have confirmed membership of 27 and 36 HAEs for the respective protoclusters, with a success rate of 70 per cent of our observed targets. The large number of spectroscopically confirmed members per cluster has enabled us for the first time to reveal the detailed kinematical structures of the protoclusters at z > 2. The clusters show prominent substructures such as clumps, filaments and velocity gradients, suggesting that they are still in the midst of rapid construction to grow to rich clusters at later times. We also estimate the dynamical masses of the clusters and substructures, assuming their local virialization. The inferred masses (∼1014 M⊙) of the protocluster cores are consistent with their being typical progenitors of the present-day most massive class of galaxy clusters (∼1015 M⊙) if we take into account the typical mass growth history of clusters. We then calculate the integrated star formation rates of the protocluster cores normalized by the dynamical masses and compare these with lower redshift descendants. We see a marked increase of star-forming activities in the cluster cores, by almost three orders of magnitude, as we go back in time to 11 billion years ago; this scales as (1 + z)6.
Approaches to Visual Search
Authors: Wolfe Jeremy M.
Published: April 2014

In her original Feature Integration Theory, Anne Treisman proposed that we process a limited set of basic preattentive, visual features in parallel across the visual field. Binding those features together into coherent, recognizable objects requires selective attention of item after item. In Treisman’s original conception, searches were divided into parallel feature searches and other serial self-terminating searches. Wolfe’s Guided Search model added the idea that the deployment of attention could be guided by preattentive information. In this view, the efficiency of search is related to the effectiveness of guidance on a continuum from perfect guidance, in the case of simple feature pop-out, to no guidance when no basic features distinguish target from distractors. This chapter reviews the evidence for different basic, preattentive features and describes the current understanding of the rules of guidance, the mechanics of visual search, and the relationship of these processes to visual awareness.
Spatial Covert Attention
Authors: Carrasco Marisa
Published: April 2014

This review focuses on how covert attention modulates perception. It explains why attention is considered a selective process, the constructs of covert attention, and spatial endogenous and exogenous attention. This review includes the effects of spatial attention on discriminability and appearance in tasks mediated by contrast sensitivity and spatial resolution.
Object- and Feature-Based Attention
Authors: Treue Stefan
Published: April 2014

The allocation of selective visual attention to a particular region of visual space has been attention’s most-studied variant. But attention can also be allocated to features, such as a particular colour or direction of motion. Studies from the visual cortex of rhesus monkeys have revealed a gain modulation across visual space that enhances the response of neurons that show a preference for the attended feature and a reduced responsiveness of those neurons tuned to the opposite feature. Such studies have also provided evidence for object-based attention, where the attentional enhancement of a neural representation affects the complex amalgamation of features that make up an object. All these forms of visual attention together create an integrated saliency map or priority map, that is, an integrated representation of relative stimulus strength and behavioural relevance across visual space that underlies our perception of the environment.
Neuronal Mechanisms of Attentional Control
Authors: Clark Kelsey L. , Noudoost Behrad , Schafer Robert J. , Moore Tirin
Published: April 2014

Covert spatial attention prioritizes the processing of stimuli at a given peripheral location, away from the direction of gaze, and selectively enhances visual discrimination, speed of processing, contrast sensitivity, and spatial resolution at the attended location. While correlates of this type of attention, which are believed to underlie perceptual benefits, have been found in a variety of visual cortical areas, more recent observations suggest that these effects may originate from frontal and parietal areas. Evidence for a causal role in attention is especially robust for the Frontal Eye Field, an oculomotor area within the prefrontal cortex. FEF firing rates have been shown to reflect the location of voluntarily deployed covert attention in a variety of tasks, and these changes in firing rate precede those observed in extrastriate cortex. In addition, manipulation of FEF activity—whether via electrical microstimulation, pharmacologically, or operant conditioning—can produce attention-like effects on behaviour and can modulate neural signals within posterior visual areas. We review this evidence and discuss the role of the FEF in visual spatial attention.
Neural Systems for Spatial Attention in the Human Brain
Authors: Beck Diane M. , Kastner Sabine
Published: April 2014

Spatial attention has been studied for over a half a century. Early behavioural work showed that attending to a location improves performance on a variety of tasks. Since then substantial progress has been made on understanding the neural mechanisms underlying these effects. This chapter reviews the neuroimaging literature, as well as related behavioural and single-cell physiology studies, on visual spatial attention. In particular, the chapter frames much of the work in the context of the biased competition theory of attention, which argues that a primary mechanism of attention is to bias competition among stimuli in the visual cortex in favour of an attended stimulus that, as a result, receives enhanced processing to guide behaviour. Accordingly, the authors have organized this chapter into two related sections. The first summarizes the effects of attention in the visual cortex and thalamus, the so-called ‘site’ of attention. The second explores the relationship between attention and fronto-parietal mechanisms which are thought to be the ‘source’ of the biasing signals exerted on the visual cortex.
A Multi-level Account of Selective Attention
Authors: Serences John T. , Kastner Sabine
Published: April 2014

To achieve behavioural goals, relevant sensory stimuli must be processed more quickly and reliably than irrelevant distracters. The ability to prioritize relevant over irrelevant stimuli is usually referred to as selective information processing, or selective attention. Over the last 50–60 years, there has been an ongoing debate about the point along the sensory–response processing stream at which selective attention operates: are relevant and irrelevant inputs segregated early in processing based on low-level featural differences, or does this segregation occur late in processing after the meaning of each stimulus has been computed? As with nearly all dichotomies in psychology, the emerging consensus is that neither extreme is correct. Instead, depending on task demands, the mechanisms of selective attention can flexibly operate on the quality of low-level sensory representations as well as on later stages of semantic analysis and decision-making.
Theory of Visual Attention (TVA)
Authors: Bundesen Claus , Habekost Thomas
Published: April 2014

The theory of visual attention introduced by Bundesen (1990) is reviewed. The authors first describe TVA as a formal computational theory of visual attention and summarize applications of TVA to psychological studies of performance (reaction times and error rates) in healthy human subjects. They then explain their neurophysiological interpretation of TVA, NTVA, and exemplify how NTVA accounts for findings from single-cell studies in primates. Finally the authors review how TVA has been applied to study attentional functions in neuropsychological, pharmacological, and genetic research.