bluuebunny/crossref_metadata_2025 huggingface dataset:
Types and continua in developmental psychopathology: Problem behaviors in school and their relationship to later antisocial behavior
Authors: Bergman Lars R. , Andershed Henrik , Andershed Anna-Karin
Published: July 2009

In the study of developmental psychopathology a dimensional, variable-oriented approach dominates over a typological approach. With the person-oriented research paradigm providing the metatheoretical framework, pros and cons of these two approaches are discussed, and it is pointed to different methodological realizations of the typological approach, and to the contexts where they might be appropriate. It is also pointed out that the two important and underused concepts of equifinality and multifinality with advantage can be incorporated in a person-oriented approach. An empirical example is given of the study of the structure of early adolescent problem behaviors and their relationship to later criminality where dimensional as well as typological analyses are carried out. The usefulness of the typological approach in studying the development and early manifestations of the personality disorder psychopathy is also discussed. It is concluded that the usefulness of a typological approach appears to be underestimated.
Representations of the caregiver–child relationship and of the self, and emotion regulation in the narratives of young children whose mothers have borderline personality disorder
Authors: Macfie Jenny , Swan Scott A.
Published: July 2009

Borderline personality disorder (BPD) represents a severe distortion in the development of attachment, self, and emotion regulation. Study of children at high risk of developing BPD may inform precursors to BPD. In a low socioeconomic status sample of 30 children aged 4–7 whose mothers have BPD and 30 normative comparisons, representations of the caregiver–child relationship and of the self, and emotion regulation were assessed with a story-stem completion measure. In contrast to comparisons and controlling for major depressive disorder, children whose mothers have BPD told stories with the following: (a) more parent–child role reversal, more fear of abandonment, and more negative mother–child and father–child relationship expectations; (b) more incongruent and shameful representations of the self; and (c) poorer emotion regulation indicated by more confusion of boundaries between fantasy and reality and between self and fantasy, more fantasy proneness, less narrative coherence, and marginally more intrusion of traumatic themes. In the sample as a whole, (a) a maladaptive caregiver–child relationship composite was associated with maternal identity disturbance and self-harm; (b) a maladaptive self-composite was associated with maternal self-harm; and (c) a maladaptive emotion regulation composite was associated with maternal identity disturbance, negative relationships, and self-harm. Results are discussed in terms of putative precursors to BPD and preventive interventions.
Early maternal separation and the trajectory of borderline personality disorder symptoms
Authors: Crawford Thomas N. , Cohen Patricia R. , Chen Henian , Anglin Deidre M. , Ehrensaft Miriam
Published: July 2009

Extended maternal separations before age 5 were evaluated as a predictor of long-term risk for offspring borderline personality disorder (BPD) symptoms in longitudinal data from a large random community sample. Early separations from mother predicted elevations in BPD symptoms assessed repeatedly from early adolescence to middle adulthood. Early separations also predicted a slower than normal rate of decline in symptoms with age. Other theoretically grounded risks were examined and shown to predict elevated BPD symptoms over the developmental trajectory. Long-term effects of early separations were largely independent of childhood temperament, child abuse, maternal problems, and parenting risks. These data provide the first prospectively collected data on the developmental course of BPD symptoms and suggest a series of environmental and other influences on these very disabling problems.
An Anatomy of Change: Profiling Cohort Difference in Beliefs and Attitudes among Anglicans in England
Authors: Village Andrew , Francis Leslie J.
Published: July 2009

Conservatism in theological belief, moral values and attitude toward ecclesiastical practices was measured in a sample of 5967 ordained and lay Anglicans in the Church of England. Average scores were compared between those who classed themselves as Anglo-catholic, broad church or evangelical, and by six different age cohorts. Overall, most measures of conservatism showed decline among more recent cohorts, but there were marked differences between traditions. Younger evangelicals showed little or no decline in theological or moral conservatism, and, in the case of Bible beliefs, were more conservative than their older counterparts. In ecclesiastical variables, however, Anglo-catholics were often more conservative and younger evangelicals showed less conservatism than other traditions or older evangelicals. The findings suggest that the divide between traditions is increasing among younger generations mainly because those in Anglo-catholic and broad-church traditions are becoming more liberal on theological or moral matters, whereas evangelicals are maintaining traditional conservative views of theology and morality but becoming less traditional in matters ecclesiastical.
Das Eppendorfer Schizophrenie-Inventar (ESI) als methodischer Ansatz in der High-Risk- und Schizotypieforschung
Authors: Maß Reinhard
Published: July 2009

Zusammenfassung. Ergebnisse früherer Untersuchungen geben Anlass zu Zweifeln an der diagnostischen Validität vieler in der Schizotypieforschung eingesetzten psychometrischen Standardverfahren. Das kürzlich vorgelegte Eppendorfer Schizophrenie-Inventar (ESI) erfasst eine Reihe von psychopathologischen Symptomen, die sich in direkten Vergleichen mit anderen klinischen Gruppen wiederholt als besonders charakteristisch für Schizophrenie erwiesen haben. In der vorliegenden Evaluationsstudie sollte die Eignung des ESI für Schizotypiestudien geprüft werden. Dazu wurden N = 57 gesunde Erwachsene mit dem ESI sowie zu Vergleichszwecken mit der Perceptual Aberration Scale, dem Continuous Performance Test und der Span of Apprehension Task untersucht. Es fanden sich hypothesengemäß signifikante Korrelationen zwischen dem ESI und allen eingesetzten Vergleichsverfahren. Diese Befunde stützen die Annahme, dass das ESI schizotypische Persönlichkeitsaspekte bei klinisch unauffälligen Probanden erfasst. Seine Verwendung in High-Risk- und Schizotypiestudien erscheint vielversprechend.
Ein Big Five-Inventar für Kinder und Jugendliche
Authors: Bleidorn Wiebke , Ostendorf Fritz
Published: July 2009

Zusammenfassung. Das Hierarchical Personality Inventory for Children (HiPIC) ist ein Fragebogen zur Messung der Big Five Persönlichkeitsfaktoren bei Kindern und Jugendlichen. Die Originalform ( Mervielde & De Fruyt, 1999 ) wurde auf der Basis von freien Elterninterviews konstruiert, um ein umfassendes Inventar zur Messung der Persönlichkeit von Kindern und Jugendlichen zu entwickeln. In der vorliegenden Studie wurde die psychometrische Qualität der deutschen Selbst- und Elternbeurteilungsversion des HiPIC in einer Stichprobe von 223 Heranwachsenden (11–15 Jahre) untersucht. Dabei ergaben sich für die Selbst- und Fremdbeurteilungsform zufriedenstellende Reliabilitäten. Die angenommene Fünf-Faktoren-Struktur ließ sich in beiden Beurteilermodi angemessen replizieren und erwies sich in Subgruppenanalysen als weitgehend invariant. Des Weiteren konnte eine hohe Kongruenz der Faktorenstrukturen der deutschen Version mit der flämischen Originalform, der französischen und auch der italienischen Version des Fragebogens nachgewiesen werden. Die zufriedenstellende Konvergenz zwischen den Selbst- und Elternbeurteilungen stützt die Validität des Verfahrens als Selbstberichtinventar für Heranwachsende.
Magnetic structure of greigite (Fe3S4) probed by neutron powder diffraction and polarized neutron diffraction
Authors: Chang Liao , Rainford Brian D. , Stewart J. Ross , Ritter Clemens , Roberts Andrew P. , Tang Yan , Chen Qianwang
Published: July 2009

We have investigated greigite (Fe3S4) using a combination of neutron powder diffraction and polarized neutron diffraction to give the first unambiguous assignment of its magnetic structure. Our results confirm that greigite has a collinear ferrimagnetic structure with antiferromagnetic coupling between the tetrahedral (A) and octahedral (B) sites. Our analysis also indicates that greigite does not have a significant vacancy concentration or spin canting. High‐resolution neutron powder diffraction results enable determination of sublattice magnetizations of the A and B sites. At room temperature, the average magnetic moments on the two sites are almost the same (∼3.0 μB), with a net magnetic moment of ∼3.0 μB per formula unit (fu). The magnetic moment of the B sites decreases slightly between 10 K and room temperature, while the A site moment is relatively stable as a function of temperature; this indicates that greigite is probably an R‐type ferrimagnet. At 10 K, the average magnetic moments of the A and B sites are 3.0 μB and 3.25 μB, respectively. Neutron diffraction measurements, coupled with magnetic measurements, on our pure synthetic greigite samples indicate that the saturation magnetization of greigite is lower than that of magnetite (Fe3O4). It is proposed that the lower magnetic moment in greigite (saturation magnetization is ∼59 A m2 kg−1) compared to magnetite is probably caused by an increased degree of covalency between iron and sulfur compared to oxygen ligands or by greater delocalization of the 3d electrons in greigite.
Aerosol analysis and forecast in the European Centre for Medium‐Range Weather Forecasts Integrated Forecast System: 2. Data assimilation
Authors: Benedetti A. , Morcrette J.‐J. , Boucher O. , Dethof A. , Engelen R. J. , Fisher M. , Flentje H. , Huneeus N. , Jones L. , Kaiser J. W. , Kinne S. , Mangold A. , Razinger M. , Simmons A. J. , Suttie M.
Published: July 2009

This study presents the new aerosol assimilation system, developed at the European Centre for Medium‐Range Weather Forecasts, for the Global and regional Earth‐system Monitoring using Satellite and in‐situ data (GEMS) project. The aerosol modeling and analysis system is fully integrated in the operational four‐dimensional assimilation apparatus. Its purpose is to produce aerosol forecasts and reanalyses of aerosol fields using optical depth data from satellite sensors. This paper is the second of a series which describes the GEMS aerosol effort. It focuses on the theoretical architecture and practical implementation of the aerosol assimilation system. It also provides a discussion of the background errors and observations errors for the aerosol fields, and presents a subset of results from the 2‐year reanalysis which has been run for 2003 and 2004 using data from the Moderate Resolution Imaging Spectroradiometer on the Aqua and Terra satellites. Independent data sets are used to show that despite some compromises that have been made for feasibility reasons in regards to the choice of control variable and error characteristics, the analysis is very skillful in drawing to the observations and in improving the forecasts of aerosol optical depth.
The 1998–2000 La Niña in the context of historically strong La Niña events
Authors: Shabbar Amir , Yu Bin
Published: July 2009

Contrary to the impacts ascribed to strong cold El Niño–Southern Oscillation (ENSO) events (La Niña) during the last half of the twentieth century, the 2‐year‐long La Niña during 1998–2000 was accompanied by abnormally warm winter conditions over most of North America. In this study, climate anomalies associated with the 1998–2000 La Niña are compared with the composite of the previous seven strong La Niña events since 1950. Despite the presence of a moderately strong La Niña, analyses of atmospheric circulation and thermal features show that the Pacific–North American sector climate was associated with a zonally elongated ridge in the extratropical North Pacific and warmer‐than‐normal sea surface temperatures (SSTs) in the western tropical Pacific that extended into the North Pacific midlatitudes during 1998–2000 event. Relative to the composite of the previous seven strong La Niñas, anomalous Walker circulation was considerably stronger and shifted westward with the ascending branch of the cell located near 110°E during the 1998–2000 event. This was associated with stronger convection and hence positive precipitation anomalies in the western Pacific. The relationship between SSTs and 500‐hPa geopotential heights over the North Pacific shows that the differences, in thermal and circulation features, between the 1998–2000 La Niña and the seven strong La Niñas bear a close resemblance to a coupled mode of extratropical ocean‐atmosphere variability as revealed by singular value decomposition analysis. This non‐ENSO coupled mode of variability, which relates the interannual variability in SSTs with 500‐hPa heights, was prominent during the winter of 1998–2000. The processes related to this mode are different from those involved in the establishment of extratropical atmospheric circulation and SST anomalies associated with typical La Niña events.
Impact of different diffusion schemes on simulated rainfall: Land‐ocean contrast
Authors: Shin Sun‐Hee , Kimoto Masahide , Ha Kyung‐Ja , Yun Kyung‐Sook
Published: July 2009

The impact of vertical diffusion schemes on simulated precipitation has been investigated using two diffusion schemes, the Mellor and Yamada level 2 (MY) and the Holtslag and Boville (HB) schemes in the Center for Climate System Research/National Institute for Environmental Studies (CCSR NIES) model. The results indicate the HB scheme reproduced strong vertical mixing over land, especially in summer hemisphere, which has apparent diurnal variation owing to strong vertical mixing in the convective boundary layer. The MY scheme displayed relatively weak vertical mixing over land but strong mixing over the ocean. The MY scheme tends to reproduce strongly the local mixing by wind shear compared to the HB scheme. The variations in the thermodynamic feature were due to the difference in the planetary boundary layer scheme results in the warmer and drier air over land and relatively colder and wetter air over the ocean. Such an apparent contrast over land and ocean leads to a horizontal gradient in temperature and changes the large‐scale circulation. The change in sea level pressure over the western equatorial Pacific, induced by the HB scheme, results in changes in the zonal and meridional pressure gradients between the equator and subtropical region, which is the main driving force of the low‐level divergence. A weakening of low‐level easterly winds owing to changes in the zonal and meridional pressure gradients has a great influence on the rising motion in the western Pacific, together with the low‐level moisture content advected toward the off‐equatorial area.
Environmental change in the subtropics during the late middle Eocene greenhouse and global implications
Authors: Okafor Chioma U. , Thomas Deborah J. , Wade Bridget S. , Firth John
Published: July 2009

Oxygen isotope records from ODP Site 1052 (Blake Nose, subtropical North Atlantic Ocean) indicate significant short‐term, high‐amplitude variability (up to 1.4‰ in about 2500 to 4000 years) during the late middle Eocene (37.9–37.5 Ma). These variations reflect a combination of changes in sea surface temperature and the oxygen isotope composition of the regional seawater. In order to independently evaluate the magnitude of SST changes at Blake Nose and better understand the nature of environmental change during the late middle Eocene, we present planktonic foraminiferal Mg/Ca data combined with δ18O data from the same samples. The calculated Mg/Ca paleotemperatures indicate a decrease in SSTs over the study interval from ∼33 to 28°C at the same time that previously published foraminiferal δ18Ocalcite values from the same samples also decrease. Thus, the δ18Ocalcite values must reflect a significant component of seawater δ18O change in order to reconcile the opposite paleotemperature trends reflected by both proxies. Calculated δ18Oseawater values decreased from ∼3‰ at 37.83 Ma to ∼2‰ at 37.6 Ma. The combined trends of the SST and δ18Oseawater cannot be explained by an increase of continental ice over this time interval. Instead, the data favor an overall weakening of the hydrological cycle as global climate transitioned from the greenhouse to icehouse.
Comparing F region ionospheric irregularity observations from C/NOFS and Jicamarca
Authors: Hysell D. L. , Hedden R. B. , Chau J. L. , Galindo F. R. , Roddy P. A. , Pfaff R. F.
Published: July 2009

Observations of plasma density irregularities associated with equatorial spread F (ESF) have been made using the Jicamarca Radio Observatory and the Plasma Langmuir Probe (PLP) and Vector Electric Field Instrument (VEFI) instruments on the Communications Navigation Outage Forecast System (C/NOFS) satellite during a close spatio‐temporal conjunction. The radar data resolution is of the order of 1 km and a few sec. in space and time, respectively. We find that coherent scatter intensifications at these scales are coincident and collocated with plasma density depletions as determined by C/NOFS. The Doppler shifts of the localized echoes are also comparable to the vertical components of the E × B plasma drifts. The strongest backscatter does not necessarily come from the deepest or most rapidly convecting depletions. This implies a complex relationship between coherent backscatter and the underlying state parameters in the ionospheric plasma.
A Screening Study on the Liability of Eight Different Female Sex Steroids to Inhibit CYP2C9, 2C19 and 3A4 Activities in Human Liver Microsomes
Authors: Laine Kari , Yasar Ümit , Widén Jolanta , Tybring Gunnel
Published: July 2009

Abstract:The aim of this study was to screen the inhibitory potential of different clinically used oestrogen and progestin hormones on CYP2C9, 2C19 and 3A4 activities in human liver microsomes. The degree of inhibition by desogestrel, 3‐ketodesogestrel, 17‐β‐oestradiol, gestodene, aethinyloestradiol, medroxyprogesterone acetate, norethisterone or L‐norgestrel were studied at 100 μM on losartan oxidation (CYP2C9), R‐omeprazole 5′‐hydroxylation (CYP2C19) and R‐omeprazole sulphoxidation (CYP3A4) with a 10‐min preincubation with NADPH in human liver microsomes prepared from 6 individual genotyped donor livers. Aethinyloestradiol was found to be a potent inhibitor (55% mean inhibition; 95% CI 32% to 79%) of losartan oxidation (CYP2C9) and R‐omeprazole 5‐hydroxylation (70%; 63% to 77%) (CYP2C19), while it had little effect on R‐omeprazole sulphoxidation (CYP3A4) activity. 17‐β‐Oestradiol did not produce significant inhibition on any of the studied enzyme activities. Of the progestin hormones studied, gestodene and 3‐ketodesogestrel were potent inhibitors of CYP2C19 (57%; 47% to 67% and 51%; 29% to 45%) and CYP3A4 (45%; 30% to 59% and 40%; 19% to 62%), but had little effect on the CYP2C9 activity. In addition, medroxyprogesterone acetate was found to inhibit CYP2C9 (55%; 45% to 65%), while not having significant effect on 2C19 or 3A4. In conclusion, the liability of clinically used female sex steroids to inhibit CYP2C9, 2C19 and 3A4 activities in human liver microsomes is very distinctive and these differences among both the oestrogen and progestin hormones may, at least in part, explain the variable results from clinical trials examining inhibitory effects of hormone replacement therapy and oral contraceptives on drug metabolism.
Endogenous spartin (SPG20) is recruited to endosomes and lipid droplets and interacts with the ubiquitin E3 ligases AIP4 and AIP5
Authors: Edwards Thomas L. , Clowes Virginia E. , Tsang Hilda T. H. , Connell James W. , Sanderson Christopher M. , Luzio J. Paul , Reid Evan
Published: July 2009

The HSPs (hereditary spastic paraplegias) are genetic conditions in which there is distal degeneration of the longest axons of the corticospinal tract, resulting in spastic paralysis of the legs. The gene encoding spartin is mutated in Troyer syndrome, an HSP in which paralysis is accompanied by additional clinical features. There has been controversy over the subcellular distribution of spartin. We show here that, at steady state, endogenous spartin exists in a cytosolic pool that can be recruited to endosomes and to lipid droplets. Cytosolic endogenous spartin is mono-ubiquitinated and we demonstrate that it interacts via a PPXY motif with the ubiquitin E3 ligases AIP4 [atrophin-interacting protein 4; WWP2 (WW domain-containing E3 ubiquitin protein ligase 2] and AIP5 (WWP1). Surprisingly, the PPXY motif, AIP4 and AIP5 are not required for spartin's ubiquitination, and so we propose that spartin acts as an adaptor for these proteins. Our results suggest that spartin is involved in diverse cellular functions, which may be of relevance to the complex phenotype seen in Troyer syndrome.
Pup, a prokaryotic ubiquitin-like protein, is an intrinsically disordered protein
Authors: Liao Shanhui , Shang Qiang , Zhang Xuecheng , Zhang Jiahai , Xu Chao , Tu Xiaoming
Published: July 2009

Pup (prokaryotic ubiquitin-like protein) from Mycobacterium tuberculosis is the first ubiquitin-like protein identified in non-eukaryotic cells. Although different ubiquitin-like proteins from eukaryotes share low sequence similarity, their 3D (three-dimensional) structures exhibit highly conserved typical ubiquitin-like folds. Interestingly, our studies reveal that Pup not only shares low sequence similarity, but also presents a totally distinguished structure compared with other ubiquitin-like superfamily proteins. Diverse structure predictions combined with CD and NMR spectroscopic studies all demonstrate that Pup is an intrinsically disordered protein. Moreover, 1H-15N NOE (nuclear Overhauser effect) data and CSI (chemical shift index) analyses indicate that there is a residual secondary structure at the C-terminus of Pup. In M. tuberculosis, Mpa (mycobacterium proteasomal ATPase) is the regulatory cap ATPase of the proteasome that interacts with Pup and brings the substrates to the proteasome for degradation. In the present paper, SPR (surface plasmon resonance) and NMR perturbation studies imply that the C-terminus of Pup, ranging from residues 30 to 59, binds to Mpa probably through a hydrophobic interface. In addition, phylogenetic analysis clearly shows that the Pup family belongs to a unique and divergent evolutionary branch, suggesting that it is the most ancient and deeply branched family among ubiquitin-like proteins. This might explain the structural distinction between Pup and other ubiquitin-like superfamily proteins.
Structure and corrosion behavior of platinum/ruthenium/nitrogen doped diamondlike carbon thin films
Authors: Khun N. W. , Liu E. , Yang G. C. , Ma W. G. , Jiang S. P.
Published: July 2009

Platinum/ruthenium/nitrogen doped diamondlike carbon (PtRuN-DLC) thin films were deposited on p-Si (100) substrates with dc magnetron cosputtering by varying the dc power applied to a Pt50Ru50 target to investigate the effect of Pt and Ru incorporation in the films on the bonding structure, adhesion strength, surface morphology, and corrosion behavior of the films by means of X-ray photoelectron spectroscopy, micro-Raman spectroscopy, microscratch test, atomic force microscopy, scanning electron microscopy, and potentiodynamic polarization test. It was found that the incorporation of Pt and Ru in the N-DLC films improved the corrosion resistance of the films in a 0.1M NaCl solution at lower polarization potentials though more sp2 bonds were formed in the films. However, the films with higher Pt and Ru contents degraded earlier than the ones with lower Pt and Ru contents at higher polarization potentials.
The ion-driven permeation experiment PERMEX
Authors: Golubeva A. V. , Mayer M. , Gasparyan Yu. M. , Roth J. , Kurnaev V. A.
Published: July 2009

A new installation PERMEX for the investigation of ion-driven permeation through metals was designed and built. A metal membrane under investigation separates two high-vacuum chambers. In the implantation chamber, the membrane surface is irradiated with a monoenergetic deuterium ion beam with an incident energy in the interval of 100–3000 eV/D. The ion flux at the surface is in a range of 1013–2×1014 D/cm2 s, the membrane temperature can be varied in the interval of 290–1050 K. The permeating deuterium flux from the outlet membrane surface to the volume of the second chamber (registration chamber) is measured by a quadrupole mass-analyzer. The outlet surface of the membrane can be cleaned by an argon ion beam. To approve the correct work of the setup a number of experiments were performed with Ni membranes. First results of experiments with tungsten membranes are presented.
Residual stress characterization of polycrystalline 3C-SiC films on Si(100) deposited from methylsilane
Authors: Liu Fang , Carraro Carlo , Chu Jiaru , Maboudian Roya
Published: July 2009

Polycrystalline 3C-SiC thin films are deposited on 100 mm Si(100) wafers via low pressure chemical vapor deposition from the precursor methylsilane in the temperature range of 700–850 °C. Residual stress, strain, and strain gradient are characterized as functions of deposition pressure, temperature, and dichlorosilane as an additional silicon source. By optimizing the deposition parameters, the residual stress is found to decrease from 1377±10 to 196±19 MPa. The low stress film exhibits a strain of 3.4×10−4, corresponding to Young’s modulus of 455 GPa, and strain gradient of −8×10−4 μm−1. The analysis suggests that the change in stress values is due to a combination of effects, in particular, thermal mismatch, grain size effect, and chemical composition.
Thermoelectric properties of p-type CoSb3 nanocomposites with dispersed CoSb3 nanoparticles
Authors: Yang L. , Hng H. H. , Li D. , Yan Q. Y. , Ma J. , Zhu T. J. , Zhao X. B. , Huang H.
Published: July 2009

CoSb 3 nanocomposites with different contents of CoSb3 nanoparticles were prepared by mixing nanosized CoSb3 particles obtained via polyol method and micron-sized particles obtained via solid state reaction. X-ray diffractometer and field emission scanning electron microscope were used to characterize the prepared products. The thermoelectric properties of the nanocomposites with different amounts of nanoparticles as dispersants were measured from room temperature to around 500 °C. Due to the grain boundaries scattering, the lattice thermal conductivity was observed to decrease as the amount of nanoparticles increased. The electrical properties were also improved by the addition of nanoparticles. The ZT value of the nanocomposites with 10 wt % of nanoparticles was nearly doubled that of the sample without any nanoparticles.
Dynamics of a beam of hot electrons propagating through a plasma in the presence of nonthermal electrons
Authors: Khalilpour H. , Foroutan G. , Moslehi-Fard M. , Li B. , Robinson P. A.
Published: July 2009

The dynamics of a beam of hot electrons traveling through a cold plasma and the generation of Langmuir waves are investigated in the presence of a nonthermal tail of electrons in the background distribution function. Using quasilinear simulations, it is shown that in the presence of the nonthermal electrons, the relaxation of the beam distribution function in velocity space is retarded and the Langmuir waves are strongly damped at low velocities. The average velocity of beam propagation is almost constant but its magnitude is larger in the presence of nonthermal electrons than their absence. It is found that the self-similarity of the system is preserved in the presence of nonthermal electrons. The effects of nonthermal electrons on the evolution of gas-dynamical parameters of the beam, including the height of plateau in the beam distribution function, its upper and lower velocity boundaries, and beam velocity width, are also studied. It is found that initially the values of the upper and lower velocity boundaries are almost unaltered, but at large times the lower (upper) boundary velocity is larger (smaller) in the presence of nonthermal electrons than without the nonthermal electrons.
Numerical studies of the influence of the dynamic contact angle on a droplet impacting on a dry surface
Authors: Yokoi Kensuke , Vadillo Damien , Hinch John , Hutchings Ian
Published: July 2009

We numerically investigated liquid droplet impact behavior onto a dry and flat surface. The numerical method consists of a coupled level set and volume-of-fluid framework, volume/surface integrated average based multimoment method, and a continuum surface force model. The numerical simulation reproduces the experimentally observed droplet behavior quantitatively, in both the spreading and receding phases, only when we use a dynamic contact angle model based on experimental observations. If we use a sensible simplified dynamic contact angle model, the predicted time dependence of droplet behavior is poorly reproduced. The result shows that precise dynamic contact angle modeling plays an important role in the modeling of droplet impact behavior.
Hydrodynamic instability of confined two-dimensional electron flow in semiconductors
Authors: Calderón-Muñoz Williams R. , Jena Debdeep , Sen Mihir
Published: July 2009

Hydrodynamic instabilities in two-dimensional electron flow in ungated semiconductors are studied here. The driving force for the electrons is an imposed voltage difference that generates a unidimensional electric field inside the semiconductor and its surroundings. The governing equations are linearized for small perturbations around the steady-flow solution. The eigenvalue spectrum determining the rates of growth and wave numbers of the oscillations is calculated. The electron flow undergoes oscillatory instability and becomes more unstable as the voltage difference is increased. The results show that it is possible to obtain oscillation frequencies of the order of terahertz, indicating the possibility of radiative power at this frequency.
Free-time and fixed end-point optimal control theory in dissipative media: Application to entanglement generation and maintenance
Authors: Mishima K. , Yamashita K.
Published: July 2009

We develop monotonically convergent free-time and fixed end-point optimal control theory (OCT) in the density-matrix representation to deal with quantum systems showing dissipation. Our theory is more general and flexible for tailoring optimal laser pulses in order to control quantum dynamics with dissipation than the conventional fixed-time and fixed end-point OCT in that the optimal temporal duration of laser pulses can also be optimized exactly. To show the usefulness of our theory, it is applied to the generation and maintenance of the vibrational entanglement of carbon monoxide adsorbed on the copper (100) surface, CO/Cu(100). We demonstrate the numerical results and clarify how to combat vibrational decoherence as much as possible by the tailored shapes of the optimal laser pulses. It is expected that our theory will be general enough to be applied to a variety of dissipative quantum dynamics systems because the decoherence is one of the quantum phenomena sensitive to the temporal duration of the quantum dynamics.
Crystal symmetry breaking of wurtzite to orthorhombic in nonpolar a-ZnO epifilms
Authors: Kuo C. C. , Liu W.-R. , Hsieh W. F. , Hsu C.-H. , Hsu H. C. , Chen L. C.
Published: July 2009

Crystal symmetry breaking of wurtzite C6V to orthorhombic C2V due to in-plane anisotropic strain was investigated for nonpolar (112¯0) ZnO epifilms grown on the R-sapphire. X-ray diffraction results reveal the epilayer is subjected to a compressive strain along the polar c-axis and tensile strains along both a-[112¯0] surface normal and in-plane p-[11¯00] axis. The polarized Raman spectra of E2 modes reveal violation of the C6V selection rules. Oppositely, the C2V configuration satisfies the selection rules for the Raman modes. The observed E1 and E2 bands in polarized optical reflection and photoluminescence spectra confirm the anisotropic strain causes the structure change to the orthorhombic one.
Titanium suboxide as an optical spacer in polymer solar cells
Authors: Roy Anshuman , Park Sung Heum , Cowan Sarah , Tong Ming Hong , Cho Shinuk , Lee Kwanghee , Heeger Alan J.
Published: July 2009

The use of a layer of titanium suboxide (TiOx) between the bulk heterojunction (BHJ) thin film and the metal contact in “plastic” solar cell has been shown to increase both the short-circuit current and the fill factor. Using a combination of optical modeling and device experiments, we clarify the role of the TiOx layer as an optical spacer. For an appropriate choice of the BHJ thickness and composition, the TiOx layer can enhance the absorption within the active layer, thereby increasing the photocurrent and the power conversion efficiency.
Strain and magnetic anisotropy of as-grown and annealed Fe films on c(4×4) reconstructed GaAs (001) surface
Authors: Lu J. , Meng H. J. , Deng J. J. , Xu P. F. , Chen L. , Zhao J. H. , Jia Q. J.
Published: July 2009

Fe films with the different thicknesses were grown on c(4×4) reconstructed GaAs (001) surfaces at low temperature by molecular-beam epitaxy. Well-ordered bcc structural Fe epitaxial films are confirmed by x-ray diffraction patterns and high-resolution cross-sectional transmission electron microscopy images. A large lattice expansion perpendicular to the surface in Fe film is observed. In-plane uniaxial magnetic anisotropy is determined by the difference between magnetizing energy along [1¯10] and [110] directions, and the constant of interfacial uniaxial magnetic anisotropy is calculated to be 1.02×10−4 J m−2. We also find that magnetic anisotropy is not obviously influenced after in situ annealing, but in-plane strain is completely changed.
Water dynamics in large and small reverse micelles: From two ensembles to collective behavior
Authors: Moilanen David E. , Fenn Emily E. , Wong Daryl , Fayer Michael D.
Published: July 2009

The dynamics of water in Aerosol-OT reverse micelles are investigated with ultrafast infrared spectroscopy of the hydroxyl stretch. In large reverse micelles, the dynamics of water are separable into two ensembles: slow interfacial water and bulklike core water. As the reverse micelle size decreases, the slowing effect of the interface and the collective nature of water reorientation begin to slow the dynamics of the core water molecules. In the smallest reverse micelles, these effects dominate and all water molecules have the same long time reorientational dynamics. To understand and characterize the transition in the water dynamics from two ensembles to collective reorientation, polarization and frequency selective infrared pump-probe experiments are conducted on the complete range of reverse micelle sizes from a diameter of 1.6–20 nm. The crossover between two ensemble and collective reorientation occurs near a reverse micelle diameter of 4 nm. Below this size, the small number of confined water molecules and structural changes in the reverse micelle interface leads to homogeneous long time reorientation.
Measurement of the electron density in a subatmospheric dielectric barrier discharge by spectral line shape
Authors: Dong Lifang , Qi Yuyan , Liu Weiyuan , Fan Weili
Published: July 2009

The electron density in a subatmospheric dielectric barrier discharge by using argon spectral line shape is measured for the first time. With the gas pressure increasing in the range of 1×104 Pa–6×104 Pa, the line profiles of argon 696.54 nm are measured. An asymmetrical deconvolution procedure is applied to separate the Gaussian and Lorentzian profile from the measured spectral line. The gas temperature is estimated by using rotational temperature of N2+. By subtracting the van der Waals broadening and partial Lorentzian instrumental broadening from the Lorentzian broadening, the Stark broadening is obtained and used to estimate the electron density. It is found that the electron density in dielectric barrier discharge increases with the increase in gas pressure.
Ferroelectric properties of epitaxial Pb(Zr,Ti)O3 thin films on silicon by control of crystal orientation
Authors: Dekkers Matthijn , Nguyen Minh D. , Steenwelle Ruud , te Riele Paul M. , Blank Dave H. A. , Rijnders Guus
Published: July 2009

Crystalline Pb(Zr,Ti)O3 (PZT) thin films between metallic-oxide SrRuO3 (SRO) electrodes were prepared using pulsed laser deposition on CeO2/yttria-stabilized zirconia buffered silicon (001) substrates. Different deposition conditions for the initial layers of the bottom SRO electrode result in an orientation switch. Either (110)- or (001)-oriented SRO thin films are obtained and the PZT films deposited on the bottom electrode continued both growth directions. The ferroelectric characteristics of the SRO/PZT/SRO capacitors are found to be strongly dependent on their crystalline orientation: PZT (001)-oriented thin films showed stable, high quality ferroelectric response, while the remnant polarization of the PZT (110)-oriented thin films only show high response after multiple switching cycles.
Radiation pattern from a cold magnetoplasma antenna
Authors: Dartora C. A. , Heilmann A. , Nobrega K. Z. , Montagner V. F. , Burkarter E. , Filho Horacio Tertuliano S.
Published: July 2009

In this paper a theoretical study of the radiation pattern of an antenna build up from a confined magnetoplasma is made. Assuming that the electron gas is in the linear regime, we derived expressions for the conductivity tensor of the plasma and the radiated electromagnetic field under the influence of both dc magnetic and ac electric externally applied fields. It is found that the radiation patterns are dependent on the relative orientations of the applied fields and in the frequency of the applied electric field.
Bulk metallic glass formation near intermetallic composition through liquid quenching
Authors: Wu W. F. , Li Y.
Published: July 2009

Metallic glass is typically formed either by liquid quenching near deep-eutectics or by solid-state reaction near the intermetallic in center of the phase diagram. In our research, two optimum bulk glass formers are synthesized in the vicinity of the intermetallic compound of Cu–Zr system through liquid quenching. It is shown that such a pair of unique glass formation is only feasible in a narrow composition range close to but clearly separated by the intermetallic composition where both the kinetic and thermodynamic conditions for the amorphous formation are matched. The discovery of this “intermetallic glass” pair through quenching allows us to find a potentially applicable host of metallic glass systems. This is followed by a discussion on its impact on understanding the formation and physics of bulk metallic glasses.
Direct evidence of imprinted vortex states in the antiferromagnet of exchange biased microdisks
Authors: Salazar-Alvarez G. , Kavich J. J. , Sort J. , Mugarza A. , Stepanow S. , Potenza A. , Marchetto H. , Dhesi S. S. , Baltz V. , Dieny B. , Weber A. , Heyderman L. J. , Nogués J. , Gambardella P.
Published: July 2009

The magnetic domain structure of patterned antiferromagnetic/ferromagnetic Ir20Mn80/Ni80Fe20 bilayer microdisk arrays has been investigated using layer-specific polarized x-ray photoemission electron microscopy and magnetic circular dichroism. Magnetic imaging at the Fe and Mn L-edge resonances provided direct evidence of a vortex state imprinted into the antiferromagnet at the interface. The opposite magnetic contrast between the layers indicated a reversed chirality of the imprinted vortex state, and a quantitative analysis of the magnetic moment from the dichroism spectra showed that uncompensated Mn spins equivalent to about 60% of a monolayer of bulk Ir20Mn80 contributed to the imprinted information at the interface.
The dependence of oxygen vacancy distributions in BiFeO3 films on oxygen pressure and substrate
Authors: Yuan G. L. , Martin L. W. , Ramesh R. , Uedono A.
Published: July 2009

The epitaxial (001)-oriented 250 nm BiFeO3/50 nm SrRuO3 films were deposited on DyScO3 and SrTiO3 substrates, respectively. Following the growth, the cooling in lower oxygen pressure results in the creation of oxygen vacancies at the surface of the BiFeO3 film and the epitaxial strain drives these vacancies to diffuse from the film surface to the film interface. The SrTiO3 substrate strongly absorbs oxygen vacancies from the BiFeO3 film while the DyScO3 substrate does not. Therefore, the depth distribution of oxygen vacancies depends on the oxygen pressure during cooling, the epitaxial strain, and the substrate absorbing oxygen vacancies.
Complete suppression of surface leakage currents in microperforated blue light-emitting diodes
Authors: Yang Y. , Cao X. A.
Published: July 2009

We investigated the effects of thermal annealing and sulfide passivation on the electrical characteristics of GaN-based light-emitting diodes (LEDs) whose active regions were integrated with a plasma-etched microhole array resembling a photonic crystal structure. Thermal annealing removed most plasma damage in the near-surface bulk region, whereas (NH4)2S treatment only passivated the defect states at the immediate surface, each producing a partial recovery of the electrical characteristics. It was found that annealing at 700 °C used in conjunction with prolonged sulfide passivation eliminated all the effects of plasma damage and resulted in a complete suppression of surface leakage in the microperforated LEDs.
Kinetic instability of ion acoustic mode in permeating plasmas
Authors: Vranjes J. , Poedts S. , Ehsan Zahida
Published: July 2009

In plasmas with electron drift (current) relative to static ions, the ion acoustic wave is subject to the kinetic instability which takes place if the directed electron speed exceeds the ion acoustic speed. The instability threshold becomes different in the case of one quasineutral electron-ion plasma propagating through another static quasineutral (target) plasma. The threshold velocity of the propagating plasma may be well below the ion acoustic speed of the static plasma. Such a currentless instability may frequently be expected in space and astrophysical plasmas.
Temperature dependent electrical resistivity of a single strand of ferromagnetic single crystalline nanowire
Authors: Kamalakar M. Venkata , Raychaudhuri A. K. , Wei Xueyong , Teng Jason , Prewett Philip D.
Published: July 2009

We have measured the electrical resistivity of a single strand of a ferromagnetic Ni nanowire of diameter 55 nm using a four-probe method in the temperature range 3–300 K. The wire used is chemically pure and is a high quality oriented single crystalline sample in which the temperature independent residual resistivity is determined predominantly by surface scattering. Precise evaluation of the temperature dependent resistivity (ρ) allowed us to identify quantitatively the electron-phonon contribution (characterized by a Debye temperature θR) as well as the spin-wave contribution, which is significantly suppressed upon size reduction.
Inhomogeneous chemical states in resistance-switching devices with a planar-type Pt/CuO/Pt structure
Authors: Yasuhara R. , Fujiwara K. , Horiba K. , Kumigashira H. , Kotsugi M. , Oshima M. , Takagi H.
Published: July 2009

The spatial distribution of chemical states in resistance-switching devices with a planar-type Pt/CuO/Pt structure has been studied by photoemission electron microscopy. It has been found that the change in resistance that occurs with the application of the first voltage is caused by the formation of a reduction path through the CuO channel between the Pt electrodes. A detailed analysis suggests that Joule-heat-assisted reduction induced by the current flowing through the device may play an important role in the formation of the conductive reduction path.
Interfacial structure of InAs/Ga1−xInxSb superlattices
Authors: Quan Maohua , Wang Lihua , Wang Ke , Guo Fengyun , Han Xiaodong , Zhao Liancheng
Published: July 2009

The interfacial structure of InAs/Ga1−xInxSb superlattices is investigated by high-resolution transmission electron microscopy imaging. We have shown that high-resolution electron microscopy with quantitative image matching can enable the relative orientation of the closely separated atomic species in InAs and Ga1−xInxSb to be resolved. We have then used this capability to determine interfacial bonds. The shift in the atomic positions associated with this modulation may lead to distortions of the interfacial structure of Ga1−xInxAs-like. The misfit dislocations in InSb-like interface are the primary mechanism for accommodating the lattice mismatch.
Evolution of photoluminescence properties of Si1−xGex nanocrystals synthesized by laser-induced pyrolysis
Authors: Ma L. B. , Schmidt T. , Guillois O. , Huisken F.
Published: July 2009

Silicon nanocrystals (NCs) doped with germanium were synthesized by CO2 laser-induced pyrolysis. Photoluminescence (PL) spectra were measured for a Si0.92Ge0.08 NC sample as a function of time, starting one day after synthesis. The position of the PL peak and the following blueshift during aging are consistent with radiative recombination of quantum-confined excitons. At the same time, the evolution of the excited state lifetime was found to saturate after approximately 10 days. In accordance with theoretical calculations, the terminal radiative decay rate was found to be two times faster than for pure Si NCs at the same emission energy.
Molecular cloning and characterisation of heparanase mRNA in the porcine placenta throughout gestation
Authors: Miles Jeremy R. , Vallet Jeffrey L. , Freking Brad A. , Nonneman Dan J.
Published: July 2009

Heparanase (HPSE) is an endoglycosidase that specifically degrades heparan sulfate, which is an abundant glycosaminoglycan of the pig placenta. The aim of the present study was to clone cDNA encoding porcine HPSE and characterise the expression level and localisation of HPSE mRNA in porcine placentas throughout gestation. Placental tissues were collected from litters on Days 25, 45, 65, 85 and 105 of gestation. Three transcript variants similar to HPSE were identified in the pig placenta. In addition, the HPSE gene was mapped to pig chromosome 8 in close proximity to quantitative trait loci for litter size and prenatal survival. Real-time polymerase chain reaction and in situ hybridisation were used to characterise the expression of two HPSE variants, namely HPSE v1 and v2, in the pig placenta throughout gestation. The expression of HPSE v1 and v2 was elevated (P < 0.01) in placentas during very early gestation (Day 25) as well as during late gestation (Days 85 and 105). Finally, HPSE v1 and v2 mRNA were localised to the cuboidal trophoblast cells of the folded bilayer located nearest to the maternal endometrium. These findings illustrate that HPSE likely plays a role in the development and modification of the pig placenta, which has implications for litter size and prenatal survival.