bluuebunny/crossref_metadata_2025 huggingface dataset:
Collisional angular momentum depolarization of OH(A) and NO(A) by Ar: A comparison of mechanisms
Authors: Brouard M. , Chadwick H. , Chang Y.-P. , Eyles C. J. , Aoiz F. J. , Kłos J.
Published: August 2011

This paper discusses the contrasting mechanisms of collisional angular momentum depolarization of OH(A2Σ+) and NO(A2Σ+) by Ar. New experimental results are presented for the collisional depolarization of OH(A) + Ar under both thermal and superthermal collision conditions, including cross sections for loss of both angular momentum orientation and alignment. Previous work on the two systems is summarized. It is shown that NO(A) + Ar depolarization is dominated by impulsive events in which the projection of the angular momentum, \documentclass[12pt]{minimal}\begin{document}${\bm j}$\end{document}j, along the kinematic apse, \documentclass[12pt]{minimal}\begin{document}$\bm {a}$\end{document}a, is nearly conserved, and in which the majority of the trajectories can be described as “nearside.” By contrast, at the relatively low collision energies sampled at 300 K, OH(A) + Ar depolarization is dominated by attractive collisions, which show a preponderance of “farside” trajectories. There is also evidence for very long-lived, complex type trajectories in which OH(A) and Ar orbit each other for several rotational periods prior to separation. Nevertheless, there is still a clear preference for conservation of the projection of \documentclass[12pt]{minimal}\begin{document}$\bm j$\end{document}j along the kinematic apse for both elastic and inelastic collisions. Experimental and theoretical results reveal that, as the collision energy is raised, the depolarization of OH(A) by Ar becomes more impulsive-like in nature.
Size induced structural modifications in copper oxide nanoparticles synthesized via laser ablation in liquids
Authors: Nath A. , Khare A.
Published: August 2011

Laser induced breakdown at copper-water interface is employed to synthesize copper oxide nanoparticles. Copper forms two stable oxides: monoclinic CuO and cubic Cu2O. The characteristic traits of laser induced plasma at copper-water interface are altered to analyze the size induced structural modifications in these oxides. The properties of laser produced plasma were varied by changing the focusing conditions of the source laser. Tightly focused condition led to formation of CuO of size ≤ 200 nm whereas laser defocusing condition produces nanocolloids of Cu2O of size less than 10 nm. These findings were attributed to high pressure (60 GPa) accompanied by high temperature at tightly focused condition which results in growth of covalent CuO whereas lower pressure (1.3 GPa) and low temperature at defocused condition probably forms symmetric Cu2O.
Electromechanical coupling properties and stability analysis of ferroelectrets
Authors: Qu Shaoxing , Yu Yalin
Published: August 2011

A constitutive theory of ferroelectrets is developed to analyze the electromechanical coupling properties and stability with large deformations. The equations of equilibrium and the condition of stability are hereby derived from the nonlinear theory. Piezoelectricity with static mechanical and electric loads and stability are investigated. The results show that the pressure and the dc voltage can both improve the piezoelectricity, i.e., increase the piezoelectric coefficient, d33. The value of d33 increases almost linearly with the dc voltage at small deformations, but possesses a nonlinear response at large deformations. To ensure that the ferroelectret is in a stable equilibrium, the corresponding Hessian should be positive definite. Two critical voltages exist and they decrease with the pre-applied pressure. This study is helpful for designing and optimizing applications of ferroelectrets.
Closed-shell ring coupled cluster doubles theory with range separation applied on weak intermolecular interactions
Authors: Toulouse Julien , Zhu Wuming , Savin Andreas , Jansen Georg , Ángyán János G.
Published: August 2011

We explore different variants of the random phase approximation to the correlation energy derived from closed-shell ring-diagram approximations to coupled cluster doubles theory. We implement these variants in range-separated density-functional theory, i.e., by combining the long-range random phase approximations with short-range density-functional approximations. We perform tests on the rare-gas dimers He2, Ne2, and Ar2, and on the weakly interacting molecular complexes of the S22 set of Jurečka et al. [P. Jurečka, J. Šponer, J. Černý, and P. Hobza, Phys. Chem. Chem. Phys. 8, 1985 (2006)10.1039/b600027d]. The two best variants correspond to the ones originally proposed by Szabo and Ostlund [A. Szabo and N. S. Ostlund, J. Chem. Phys. 67, 4351 (1977)10.1063/1.434580]. With range separation, they reach mean absolute errors on the equilibrium interaction energies of the S22 set of about 0.4 kcal/mol, corresponding to mean absolute percentage errors of about 4%, with the aug-cc-pVDZ basis set.
Stochastic dynamics of charge fluctuations in dusty plasma: A non-Markovian approach
Authors: Asgari H. , Muniandy S. V. , Wong C. S.
Published: August 2011

Dust particles in typical laboratory plasma become charged largely by collecting electrons and/or ions. Most of the theoretical studies in dusty plasma assume that the grain charge remains constant even though it fluctuates due to the discrete nature of the charge. The rates of ions and electrons absorption depend on the grain charge, hence its temporal evolution. Stochastic charging model based on the standard Langevin equation assumes that the underlying process is Markovian. In this work, the memory effect in dust charging dynamics is incorporated using fractional calculus formalism. The resulting fractional Langevin equation is solved to obtain the amplitude and correlation function for the dust charge fluctuation. It is shown that the effects of ion-neutral collisions can be interpreted in phenomenological sense through the nonlocal fractional order derivative.
The effect of magnetostatic coupling on spin configurations in ultrathin multilayers
Authors: Tekielak M. , Gieniusz R. , Kisielewski M. , Mazalski P. , Maziewski A. , Zablotskii V. , Stobiecki F. , Szymański B. , Schäfer R.
Published: August 2011

(Co/Au)N ultrathin multilayers with perpendicular and in-plane magnetic anisotropy were studied experimentally using a combination of ferromagnetic resonance, magneto-optical magnetometry and microscopy (with both in-plane and out-of-plane magnetization-sensitive longitudinal and polar Kerr effects), and magnetic force microscopy (MFM). Three-dimensional magnetization distributions were reconstructed from micromagnetic simulations complemented by the measured magnetic parameters of the multilayers and observations by Kerr microscopy and MFM. It is shown that, in the reorientation phase transition (RPT) zone – the range of anisotropy characterized by 0 < Q < 1 (the ratio of the anisotropy energy to be gained by magnetization along the easy axis perpendicular to the sample surface, and the magnetostatic energy of a uniformly magnetized layer along the surface normal) – the three-dimensional magnetization distributions consist of alternating pairs of vortices and half-antivortices, both with in-plane magnetized cores and elliptical cross-sections. It is shown that an increase in N leads to a significant increase in the saturation field as well as changes in the hysteresis loop shape, domain structure size, and geometry. We demonstrate by simulations and prove by experimentation that, in multilayers with Q < 1, an increase in N induces the nucleation of out-of-plane magnetized domains, which then triggers magnetostatic interlayer coupling and RPT onset to out-of-plane magnetization states. We report on the observations of large micrometer-sized metastable domains (connected with the vortex cores) with the in-plane magnetization modulated by submicrometer-sized out-of-plane domains with sizes defined mainly by magnetostatics.
Modelling and Simulation of the Advanced Plasma Source
Authors: Schroeder Benjamin , Peter Ralf , Harhausen Jens , Ohl Andreas
Published: August 2011

Plasma ion assisted-deposition (PIAD) is a combination of conventional thermal evaporation deposition and plasma-beam surface modification; it serves as a well-established technology for the creation of high quality coatings on mirrors, lenses, and other optical devices. It is closely related to ion-assisted deposition to the extent that electrons preserve quasineutrality of the ion beam. This paper investigates the Advanced Plasma Source (APS), a plasma beam source employed for PIAD. A field enhanced glow discharge generates a radially expanding plasma flow with an ion energy of about 80-120 eV. Charge exchange collisions with the neutral background gas (pressure 0.1 Pa and below) produce a cold secondary plasma, which expands as well. A model is developed which describes the primary ions by a simplified Boltzmann equation, the secondary ions by the equations of continuity and momentum balance, and the electrons by the condition of Boltzmann equilibrium. Additionally, quasineutrality is assumed. The model can be reduced to a single nonlinear differential equation for the velocity of the secondary ions, which has several removable singularities and one essential singularity, identified as the Bohm singularity. Solving the model yields macroscopic plasma features, such as fluxes, densities, and the electrical field. An add-on Monte-Carlo simulation is employed to calculate the ion energy distribution function at the substrate. All results compare well to experiments conducted at a commercial APS system.
Time-dependent fluorescence in nanoconfined solvents: Linear-response approximations and Gaussian statistics
Authors: Laird Brian B. , Thompson Ward H.
Published: August 2011

The time-dependent fluorescence of a model dye molecule in a nanoconfined solvent is used to test approximations based on the dynamic and static linear-response theories and the assumption of Gaussian statistics. Specifically, the results of nonequilibrium molecular-dynamics simulations are compared to approximate expressions involving time correlation functions obtained from equilibrium simulations. Solvation dynamics of a model diatomic dye molecule dissolved in acetonitrile confined in a spherical hydrophobic cavity of radius 12, 15, and 20 Å is used as the test case. Both the time-dependent fluorescence energy, expressed as the normalized dynamic Stokes shift, and the time-dependent position of the dye molecule after excitation are examined. While the dynamic linear-response approximation fails to describe key aspects of the solvation dynamics, assuming Gaussian statistics reproduces the full nonequilibrium simulations well. The implications of these results are discussed.
Comparison of Brownian dynamics algorithms with hydrodynamic interaction
Authors: Schmidt Ricardo Rodríguez , Cifre José G. Hernández , de la Torre José García
Published: August 2011

The hydrodynamic interaction is an essential effect to consider in Brownian dynamics simulations of polymer and nanoparticle dilute solutions. Several mathematical approaches can be used to build Brownian dynamics algorithms with hydrodynamic interaction, the most common of them being the exact but time demanding Cholesky decomposition and the Chebyshev polynomial expansion. Recently, Geyer and Winter [J. Chem. Phys. 130, 1149051 (2009)]10.1063/1.3089668 have proposed a new approximation to treat the hydrodynamic interaction that seems quite efficient and is increasingly used. So far, a systematic comparison among those approaches has not been clearly made. In this paper, several features and the efficiency of typical implementations of those approaches are evaluated by using bead-and-spring chain models. The different sensitivity to the bead overlap detected for the different implementations may be of interest to select the suitable algorithm for a given simulation.
Deflection of rotating symmetric top molecules by inhomogeneous fields
Authors: Gershnabel E. , Averbukh I. Sh.
Published: August 2011

We consider deflection of rotating symmetric top molecules by inhomogeneous optical and static electric fields, compare results with the case of linear molecules, and find new singularities in the distribution of the scattering angle. Scattering of the prolate/oblate molecules is analyzed in detail, and it is shown that the process can be efficiently controlled by means of short and strong femtosecond laser pulses. In particular, the angular dispersion of the deflected molecules may be dramatically reduced by laser-induced molecular prealignment. We first study the problem by using a simple classical model, and then find similar results by means of more sophisticated methods, including the formalism of adiabatic invariants and direct numerical simulation of the Euler-Lagrange equations of motion. The suggested control scheme opens new ways for many applications involving molecular focusing, guiding, and trapping by optical and static fields.
Application of an efficient multireference approach to free-base porphin and metalloporphyrins: Ground, excited, and positive ion states
Authors: Chaudhuri Rajat K , Freed Karl F. , Chattopadhyay Sudip , Mahapatra Uttam Sinha
Published: August 2011

The improved virtual orbital-complete active space configuration interaction (IVO-CASCI) method is applied to determine the geometries of the ground state of free-base porphin and its metal derivatives, magnesium and zinc porphyrins. The vertical excitation energies and ionization potentials are computed at these optimized geometries using an IVO-based version of multireference Möller-Plesset (IVO-MRMP) perturbation theory. The geometries and excitation energies obtained from the IVO-CASCI and IVO-MRMP methods agree well with experiment and with other correlated many-body methods. We also provide the ground state vibrational frequencies for free-base porphin and Mg-porphyrin. All frequencies are real in contrast to self-consistent field treatments which yield an imaginary frequency. Ground state normal mode frequencies (scaled) of free-base porphin and magnesium porphyrin from IVO-CASCI and complete active space self-consistent field methods are quite similar and are consistent with Becke-Slater-Hartree-Fock exchange and Lee-Yang-Parr correlation density functional theory calculations and with experiment. In addition, geometries are determined for low-lying excited state triplets and for positive ion states of the molecules. To our knowledge, no prior experimental and theoretical data are available for these excited state geometries of magnesium and zinc porphyrins. Given that the IVO-CASCI and IVO-MRMP computed geometries and excitation energies agree favorably with experiment and with available theoretical data, our predicted excited state geometries should be equally accurate.
Thermal rupture of linear alternate copolymers: A molecular dynamics study
Authors: Ghosh A. , Bo Lee Won
Published: August 2011

The thermal rupture of a linear alternating copolymer fixed at one end and pulled by a constant force at the other end has been studied using molecular dynamics simulation. The dependence of the first breakage time distribution on the mass ratio of the constituent beads has been studied. The Arrhenian nature of the scission process has been confirmed and an estimate of the effective energy barrier has been made.
Three-dimensional k · p real-space quantum transport simulations of p-type nanowire transistors: Influence of ionized impurities
Authors: Pons Nicolas , Cavassilas Nicolas , Raymond Laurent , Michelini Fabienne , Lannoo Michel , Bescond Marc
Published: August 2011

We present a three-dimensional quantum transport simulator for p-type nanowire transistors. This self-consistent model expresses a six-band k · p Hamiltonian within the non-equilibrium Green’s function formalism. Transport properties are analyzed with and without the presence of ionized impurities in the channel. We observe that inter-subband coupling generates a rich structure of peaks in the transmission coefficients even in the intrinsic situation. A single donor leads to a current decrease whereas its acceptor counterpart induces complicated resonant and anti-resonant features. Unlike n-type devices, our conclusions pinpoint that the p-type nanowire transistors exhibit intricate transmission variations that can potentially generate larger variability and whose modeling requires a multi-band based simulator.
Correlated photon-pair generation in a periodically poled MgO doped stoichiometric lithium tantalate reverse proton exchanged waveguide
Authors: Lobino M. , Marshall G. D. , Xiong C. , Clark A. S. , Bonneau D. , Natarajan C. M. , Tanner M. G. , Hadfield R. H. , Dorenbos S. N. , Zijlstra T. , Zwiller V. , Marangoni M. , Ramponi R. , Thompson M. G. , Eggleton B. J. , O’Brien J. L.
Published: August 2011

We demonstrate photon-pair generation in a reverse proton exchanged waveguide fabricated on a periodically poled magnesium doped stoichiometric lithium tantalate substrate. Detected pairs are generated via a cascaded second order nonlinear process where a pump laser at wavelength of 1.55 μm is first doubled in frequency by second harmonic generation and subsequently downconverted around the same spectral region. Pairs are detected at a rate of 42/s with a coincidence to accidental ratio of 0.7. This cascaded pair generation process is similar to four-wave-mixing where two pump photons annihilate and create a correlated photon pair.
Rapid diagnosis of electromigration induced failure time of Pb-free flip chip solder joints by high resolution synchrotron radiation laminography
Authors: Tian Tian , Xu Feng , Kyu Han Jung , Choi Daechul , Cheng Yin , Helfen Lukas , Di Michiel Marco , Baumbach Tilo , Tu K. N.
Published: August 2011

We performed a rapid diagnosis of electromigration induced void nucleation and growth in Pb-free flip chip solder joints. Quantitative measurements of the growth rate of voids during the stressing by 1.0 × 104 A/cm2 and 7.5 × 103 A/cm2 at 125 °C were conducted by synchrotron radiation high resolution x-ray laminography. The results were analyzed by the statistical model of Weibull distribution function [W. Weibull, ASME Trans. J. Appl. Mech. 18(3), 293 (1951)] of lifetime data. The Johnson-Mehl-Avrami phase transformation theory is proposed to provide a physical link to the statistical model and to estimate the lifetime of the joints at early stages.
Direct ovarian - uterine transfer of progesterone increases embryo survival in gilts
Authors: Athorn R. Z. , Stott P. , Bouwman E. G. , Ashman R. , O'Leary S. , Nottle M. , Langendijk P.
Published: August 2011

This study employed a unilateral ovariectomy model to investigate the relevance of the local supply of progesterone (ovary) compared with the systemic supply of progesterone, in terms of embryo survival in the ipsilateral uterine horn as opposed to the contralateral uterine horn. Thirty gilts were unilaterally ovariectomised (ULO) during the luteal stage of their first oestrous cycle. Half of the ULO gilts were fed at 1.2 maintenance requirement (M), while the other half were fed at 2.4 M. Across ULO gilts 0.8 more embryos survived in the ipsilateral horn compared with the contralateral horn at Day 35 of gestation (P < 0.05). In ULO gilts on the 2.4 M feed level the difference (+1.3; P < 0.05) between the ipsi- and contralateral horn was more pronounced than on the 1.2 M feed level (+0.4; NS). The higher feed level reduced circulating levels of systemic progesterone on Day 5 of pregnancy but not embryo survival at Day 35. However, post-implantation embryo survival was lower on the low feed level. In conclusion, these data indicate that local progesterone supply from the ovaries to the uterus contributes to the probability of embryo survival.
Study of the proacrosin - acrosin system in epididymal, ejaculated and in vitro capacitated boar spermatozoa
Authors: Puigmulé Marta , Fàbrega Anna , Yeste Marc , Bonet Sergi , Pinart Elisabeth
Published: August 2011

The present study aimed to develop a set of sensitive assays to evaluate the presence of different isoforms, the activity degree, and the immunolocalisation of proacrosin–acrosin in sexually mature boars. The goal was to determine the proacrosin–acrosin status of boar spermatozoa throughout epididymal maturation, during ejaculation and after in vitro capacitation. In epididymal samples, proacrosin expression was high in all regions studied. In contrast, α- and β-acrosin expression was low in the caput region, and increased progressively during maturation and in vitro capacitation. In in vitro capacitated samples, the acrosin activity was 2.25 times higher than in the ejaculated samples and immunolocalisation analyses showed redistribution of proacrosin–acrosin at the apical ridge of the head. This study provides relevant data about the expression, localisation and activity of the proacrosin–acrosin system in healthy adult boars that can be used as a base to analyse changes in the proacrosin–acrosin system under pathological conditions.
Restricted feed intake in lactating primiparous sows. I. Effects on sow metabolic state and subsequent reproductive performance
Authors: Patterson J. L. , Smit M. N. , Novak S. , Wellen A. P. , Foxcroft G. R.
Published: August 2011

The effects of feed restriction (60% of anticipated feed intake; Restrict; n = 60) during the last week of a 21-day lactation in primiparous sows compared with feeding at 90% of anticipated feed intake (Control; n = 60) on sow metabolic state, litter growth and sow reproductive performance after weaning were compared. Metabolisable energy (ME) derived from feed was lower, ME derived from body tissues was higher and litter growth rate was reduced (all P < 0.05) in Restrict sows during the last week of lactation. Treatment did not affect weaning-to-oestrus interval, pregnancy rate, ovulation rate, embryonic survival or the number of live embryos (P > 0.05) at Day 30 of gestation: However, embryo weight was greater (P < 0.05) in Control than in Restrict sows (1.55 ± 0.04 vs 1.44 ± 0.04 g, respectively). These data suggest the biology of the commercial sow has changed and reproductive performance of contemporary primiparous sows is increasingly resistant to the negative effects of lactational catabolism. Overall, catabolism negatively affected litter weaning weight and embryonic development of the next litter, but the extent to which individual sows used tissue mobilisation to support these litter outcomes was highly variable.
Exosomal evasion of humoral immunotherapy in aggressive B-cell lymphoma modulated by ATP-binding cassette transporter A3
Authors: Aung Thiha , Chapuy Bjoern , Vogel Daniel , Wenzel Dirk , Oppermann Martin , Lahmann Marlen , Weinhage Toni , Menck Kerstin , Hupfeld Timo , Koch Raphael , Trümper Lorenz , Wulf Gerald G.
Published: August 2011

Targeting the surface of malignant cells has evolved into a cornerstone in cancer therapy, paradigmatically introduced by the success of humoral immunotherapy against CD20 in malignant lymphoma. However, tumor cell susceptibility to immunochemotherapy varies, with mostly a fatal outcome in cases of resistant disease. Here, we show that lymphoma exosomes shield target cells from antibody attack and that exosome biogenesis is modulated by the lysosome-related organelle-associated ATP-binding cassette (ABC) transporter A3 (ABCA3). B-cell lymphoma cells released exosomes that carried CD20, bound therapeutic anti-CD20 antibodies, consumed complement, and protected target cells from antibody attack. ABCA3, previously shown to mediate resistance to chemotherapy, was critical for the amounts of exosomes released, and both pharmacological blockade and the silencing of ABCA3 enhanced susceptibility of target cells to antibody-mediated lysis. Mechanisms of cancer cell resistance to drugs and antibodies are linked in an ABCA3-dependent pathway of exosome secretion.
High-temperature high-pressure phases of lithium from electron force field (eFF) quantum electron dynamics simulations
Authors: Kim Hyungjun , Su Julius T. , Goddard William A.
Published: August 2011

We recently developed the electron force field (eFF) method for practical nonadiabatic electron dynamics simulations of materials under extreme conditions and showed that it gave an excellent description of the shock thermodynamics of hydrogen from molecules to atoms to plasma, as well as the electron dynamics of the Auger decay in diamondoids following core electron ionization. Here we apply eFF to the shock thermodynamics of lithium metal, where we find two distinct consecutive phase changes that manifest themselves as a kink in the shock Hugoniot, previously observed experimentally, but not explained. Analyzing the atomic distribution functions, we establish that the first phase transition corresponds to (
i
) an fcc-to-cI16 phase transition that was observed previously in diamond anvil cell experiments at low temperature and (
ii
) a second phase transition that corresponds to the formation of a new amorphous phase (amor) of lithium that is distinct from normal molten lithium. The amorphous phase has enhanced valence electron-nucleus interactions due to localization of electrons into interstitial locations, along with a random connectivity distribution function. This indicates that eFF can characterize and compute the relative stability of states of matter under extreme conditions (e.g., warm dense matter).
Labour protests in Egypt: causes and meanings
Authors: El-Mahdi Rabab
Published: August 2011

Egypt has experienced a wave of unprecedented labour protests since December 2006. Refuting moral economy and rational choice arguments as a basis for understanding labour unrest in Egypt, this paper argues that this wave of protests is an outcome of the rupture of the hegemonic ruling pact governing Egypt since 1952. As such, this movement, which includes both industrial workers as well as white-collar state employees, should be interpreted beyond its immediate material demands. Rather, the paper argues, the changing constituency, tactics, and internal organisation of the movement all point to the potential role that it can play in further eroding the corporatist–authoritarian structure governing state-society relations in Egypt. The paper concludes that this movement might be carrying the potential for wider democratisation.
From resistance to governance: Eritrea's trouble with transition
Authors: Connell Dan
Published: August 2011

Nation-building in Africa was hobbled by the inheritance of centralised, authoritarian ‘states’ prior to the consolidation of nations within them. Armed liberation movements overcame this to some degree by constructing common identities out of the struggle to throw off foreign rule. Yet the degree and kind of control inherent in such a militarised project fuelled despotism in the post-war state. Eritrea seemed to break this mould, with its high level of popular participation in its war effort, its engagement in social transformation during the fighting, and the participatory constitution-building process that followed its victory. Yet less than a decade on, the liberation front shut down the press, jailed its critics, and turned the country into a political prison. This article will situate this reversal within the transition from colony to independent state, explore its specific characteristics, and consider the prospects for a more democratic outcome.
The Egyptian revolution: crisis of neoliberalism and the potential for democratic politics
Authors: Joya Angela
Published: August 2011

This paper argues that the Egyptian revolution of 25 January 2011 has to be understood in the context of neoliberal economic shift. The two decades of economic liberalisation policies were accompanied by authoritarianism while at the same time these policies opened up opportunities for crony capitalism. Post Mubarak Egypt has witnessed positive developments such as the rise of political parties, independent trade union federations and other social groups aiming to participate in rebuilding a democratic society. The paper explores the potentials for, and challenges against, building a democratic society in Egypt.
Escape to infinity in the presence of magnetic fields
Authors: Díaz-Cano A. , González-Gascón F.
Published: August 2011

Escape to infinity is proved to occur when a charge moves under the action of the magnetic field created by a finite number of planar closed wires.
Emergence of male-biased genes on the chicken Z-chromosome: Sex-chromosome contrasts between male and female heterogametic systems: Figure 1.
Authors: Ellegren Hans
Published: August 2011

There has been extensive traffic of male-biased genes out of the mammalian and Drosophila X-chromosomes, and there are also reports of an under-representation of male-biased genes on the X. This may reflect an adaptive process driven by natural selection where an autosomal location of male-biased genes is favored since male genes are only exposed to selection one-third of the time when X-linked. However, there are several alternative explanations to “out-of-the-X” gene movement, including mutational bias and a means for X-linked genes to escape meiotic sex chromosome inactivation (MSCI) during spermatogenesis. As a critical test of the hypothesis that genomic relocation of sex-biased genes is an adaptive process, I examined the emergence, and loss, of genes on the chicken Z-chromosome, i.e., a female heterogametic system (males ZZ, females ZW). Here, the analogous prediction would be an emergence of male-biased genes onto, not a loss from, the Z-chromosome because Z is found more often in males than autosomes are. I found that genes expressed in testis but not in ovary are highly over-represented among genes that have emerged on the Z-chromosome during avian evolution. Moreover, genes with male-biased expression are similarly over-represented among new Z-chromosomal genes. Interestingly, genes with female-biased expression have more often moved from than to the Z-chromosome. These observations show that male and female heterogametic organisms display opposing directionalities in the emergence and loss of sex-biased genes on sex chromosomes. This is consistent with theoretical models on the evolution of sexually antagonistic genes in which new mutations are at least partly dominant.
Epigenetic alterations in the lateral amygdala are required for reconsolidation of a Pavlovian fear memory
Authors: Maddox Stephanie A. , Schafe Glenn E.
Published: August 2011

Epigenetic mechanisms have been widely implicated in synaptic plasticity and in memory consolidation, yet little is known about the role of epigenetic mechanisms in memory reconsolidation processes. In the present study, we systematically examine the role of histone acetylation and DNA methylation in the reconsolidation of an amygdala-dependent Pavlovian fear memory. We first show that the acetylation of histone 3 (H3), but not histone 4 (H4), is regulated following auditory fear memory retrieval in the lateral nucleus of the amygdala (LA). We next show that histone deacetylase (HDAC) inhibition in the LA enhances both retrieval-induced histone acetylation and reconsolidation of an auditory fear memory. Conversely, inhibition of DNA methytransferase (DNMT) activity in the LA significantly impairs both retrieval-related H3 acetylation and fear memory reconsolidation. The effects of HDAC and DNMT inhibitors on fear memory reconsolidation were observed to be time-limited and were not evident in the absence of memory reactivation. Further, memories lost following DNMT inhibition were not observed to be vulnerable to spontaneous recovery, reinstatement, or to a shift in testing context, suggesting that memory impairment was not the result of facilitated extinction. Finally, pretreatment with the HDAC inhibitor was observed to rescue the reconsolidation deficit induced by the DNMT inhibitor. These findings collectively suggest that histone acetylation and DNA methylation are critical for reconsolidation of fear memories in the LA.
Pathology of oesophagitis
Authors: Maguire Aoife , Sheahan Kieran
Published: August 2011

Maguire A & Sheahan K  (2012) Histopathology 60, 864–879 Pathology of oesophagitis

Endoscopic oesophageal biopsies are common in daily pathology practice. Inflammation and damage of the oesophageal mucosa is known as oesophagitis and is common worldwide. A variety of physical, chemical and infectious agents cause oesophagitis. The oesophagus has a limited range of responses to a wide variety of injuries, and so histopathological features of different diseases often overlap. The pathologist is reliant on the endoscopist for the ‘macroscopic description’ of the oesophagus. Access to the endoscopic images enhances the pathologist’s overall interpretation of the case. Correlating clinical, endoscopic and microscopic findings may be crucial in arriving at the correct diagnosis. In this review, we present clinicopathological descriptions of the major types of oesophagitis.
Racial Harassment, Ethnic Concentration, and Economic Conditions*
Authors: Dustmann Christian , Fabbri Francesca , Preston Ian
Published: August 2011

In this paper, we analyse the association between the spatial concentration of ethnic minorities and racial harassment. Ethnic concentration relates to racial harassment through at least three channels: hostility in the attitudes of majority individuals that finds expression in harassment behaviour, the probability that minority individuals meet majority individuals, and the cost of expressing hostility aggressively. Thus, harassment cannot simply be modelled as a stronger form of hostility. Using unique data for Britain, we show that, in areas of higher local ethnic concentration, experience of harassment is lower, even though hostility on the side of the majority population is not.
Restrictions to G(𝔽p) and G(r) of rational G-modules
Authors: Friedlander Eric M.
Published: August 2011

We fix a prime p and consider a connected reductive algebraic group G over a perfect field k which is defined over 𝔽p. Let M be a finite-dimensional rational G-module M, a comodule for k[G]. We seek to somewhat unravel the relationship between the restriction of M to the finite Chevalley subgroup G(𝔽p)⊂G and the family of restrictions of M to Frobenius kernels G(r) ⊂G. In particular, we confront the conundrum that if M is the Frobenius twist of a rational G-module N,M=N(1), then the restrictions of M and N to G(𝔽p) are equal whereas the restriction of M to G(1) is trivial. Our analysis enables us to compare support varieties (and the finer non-maximal support varieties) for G(𝔽p) and G(r) of a rational G-module M where the choice of r depends explicitly on M.
Spectral Finite Element Formulation for Nanorods via Nonlocal Continuum Mechanics
Authors: Narendar S. , Gopalakrishnan S.
Published: August 2011

In this article, the Eringen’s nonlocal elasticity theory has been incorporated into classical/local Bernoulli-Euler rod model to capture unique properties of the nanorods under the umbrella of continuum mechanics theory. The spectral finite element (SFE) formulation of nanorods is performed. SFE formulation is carried out and the exact shape functions (frequency dependent) and dynamic stiffness matrix are obtained as function of nonlocal scale parameter. It has been found that the small scale affects the exact shape functions and the elements of the dynamic stiffness matrix. The results presented in this paper can provide useful guidance for the study and design of the next generation of nanodevices that make use of the wave dispersion properties of carbon nanotubes.
On Comparative Performance Testing of Prechamber and Open Chamber Laser Ignition
Authors: Joshi Sachin , Loccisano Frank , Yalin Azer P. , Montgomery Dave T.
Published: August 2011

Laser ignition is a potential ignition technology to achieve reliable lean burn ignition in high brake mean effective pressure (BMEP) internal combustion engines. The technology has the potential to increase brake thermal efficiency and reduce exhaust emissions. This submission reports on engine testing of a Caterpillar G3516C stationary natural gas fueled engine with three types of ignition approaches: (i) nonfueled electric prechamber plug with electrodes at the base of the prechamber, (ii) nonfueled laser prechamber plug with laser spark in the middle of the prechamber, and (iii) open chamber plug with laser spark in the main chamber. In the second configuration, a stock nonfueled prechamber plug was modified to incorporate a sapphire window and a focusing lens to form a laser prechamber plug. A 1064 nm Q-switched Nd:YAG laser was used to create laser sparks. For these tests, a single cylinder of the engine was retrofitted with the laser plug while the remaining cylinders were run with conventional electric ignition system at baseline ignition timing of 24 deg before top dead center (BTDC). The performances of the three plugs were compared in terms of indicated mean effective pressures (IMEP), mass burn fraction duration and coefficient of variation (COV) of IMEP, and COV of peak pressure location. Test data show comparable performance between electric and laser prechamber plugs, albeit with a lower degree of variability in engine’s performance for electric prechamber plug compared to the laser prechamber plug. The open chamber plug exhibited poorer variability in engine performance. All results are discussed in the context of prechamber and engine fluid mechanics.
A Fast Influence Coefficient Method for Aerodynamically Mistuned Disks Aeroelasticity Analysis
Authors: Hsu Kwen , Hoyniak Daniel
Published: August 2011

The blade geometric variations are usually ignored in the prediction of bladed disk aerodynamic damping values. This situation is the result of the high computational cost associated with the full-annulus unsteady flow CFD models required to account for these blade geometric differences. This paper presents an approach that can account for these geometric differences with high fidelity and at a reasonable one-time cost. The approach is based on the use of the influence-coefficient (IC) method together with a set of sensitivity coefficients defined for the blade geometry changing effects. The sensitivity coefficients make use of a set of principal component analysis (PCA) modes that describe the measured blade geometry variation. Once the sensitivity coefficients are determined, they are used to construct the IC matrices and to predict the aerodynamic damping values associated with the geometrically mistuned disk. The currently proposed method is unique in two aspects. The first is to follow the observed physics while making assumptions in the linearization process to reduce the number of required sensitivity coefficients. The second is to construct the multiblade CFD model, with blades of different geometries, in a unique way to reduce the data generation costs. Two IC approximation formulas were developed. If NP denotes the number of PCA modes used to describe the blade geometric variation, one formula reduces the number of required multiblade unsteady CFD models from (NP +1) [3] to (NP +1) [2], the other reduces the number of CFD models from (NP +1) [2] to NP +1. Results obtained from these two formulas are compared and validated.
Optimization of a Stationary Diesel Engine Fuelled With Crude Rice Bran Oil Methyl Ester Using the Taguchi Method
Authors: Saravanan S. , Nagarajan G. , Sampath S.
Published: August 2011

In the present work an attempt was made to reduce the NOx emission of crude rice bran oil methyl ester (CRBOME) with a marginal increase in smoke density and decrease in brake thermal efficiency in a stationary CI engine. Three factors namely fuel injection timing, quantity of exhaust gases recycled and fuel injection pressure were chosen. Experiments were designed by employing design of experiments method and tests were conducted with combination of factors as per Taguchi’s L9 orthogonal array. Percentage contribution of each factor and the most influencing factor in controlling the response variables (NOx emission, smoke density and brake thermal efficiency) were obtained through ANOVA. Multi-response signal-to-noise (MRSN) ratio was calculated and the optimum combination level of factors was obtained simultaneously using Taguchi’s parametric design. Among the three, the most influencing factor for the chosen objective was found out by analyzing the MRSN ratio through ANOVA. The optimum combination obtained shows a lower NOx emission with less influence on smoke density and brake thermal efficiency.
Imaging and phase identification of Cu2ZnSnS4 thin films using confocal Raman spectroscopy
Authors: Cheng A.-J. , Manno M. , Khare A. , Leighton C. , Campbell S. A. , Aydil E. S.
Published: August 2011

Copper zinc tin sulfide (Cu2ZnSnS4 or CZTS) is a potential candidate for next generation thin film solar cells because it contains abundant and nontoxic elements and exhibits high light absorption. Thin films of CZTS are typically synthesized by sulfidizing a stack of zinc, copper, and tin films. In addition to CZTS, a variety of binary and ternary metal sulfides can form and distinguishing among phases with similar crystal structure can be difficult. Herein, the authors show that confocal Raman spectroscopy and imaging can distinguish between CZTS and the other binary and ternary sulfides. Specifically, Raman spectroscopy was used to detect and distinguish between CZTS (338 cm−1), Cu2SnS3 (298 cm−1), and Cu4SnS4 (318 cm−1) phases through their characteristic scattering peaks. Confocal Raman spectroscopy was then used to image the distribution of coexisting phases and is demonstrated to be a useful tool for examining the heterogeneity of CZTS films. The authors show that, during sulfidation of a zinc/copper/tin film stack, ternary sulfides of copper and tin, such as Cu2SnS3 form first and are then converted to CZTS. The reason for formation of Cu2SnS3 as an intermediary to CZTS is the strong tendency of copper and tin to form intermetallic alloys upon evaporation. These alloys sulfidize and form copper tin sulfides first, and then eventually convert to CZTS in the presence of zinc. As a consequence, films sulfidized for 8 h at 400 °C contain both CZTS and Cu2SnS3, whereas films sulfidized at 500 °C contain nearly phase-pure CZTS. In addition, using Cu Kα radiation, the authors identify three CZTS X-ray diffraction peaks at 37.1° [(202)], 38° [(211)], and 44.9° [(105) and (213)], which are absent in ZnS and very weak in Cu2SnS3.
Reaction mechanisms of atomic layer deposition of TaNx from Ta(NMe2)5 precursor and H2-based plasmas
Authors: Knoops H. C. M. , Langereis E. , van de Sanden M. C. M. , Kessels W. M. M.
Published: August 2011

The reaction mechanisms of plasma-assisted atomic layer deposition (ALD) of TaNx using Ta(NMe2)5 were studied using quadrupole mass spectrometry (QMS). The fact that molecule dissociation and formation in the plasma have to be considered for such ALD processes was illustrated by the observation of 4% NH3 in a H2-N2 (1:1) plasma. Using QMS measurements the reaction products during growth of conductive TaNx using a H2 plasma were determined. During the Ta(NMe2)5 exposure the reaction product HNMe2 was detected. The amount of adsorbed Ta(NMe2)5 and the amount of HNMe2 released were found to depend on the number of surface groups generated during the plasma step. At the beginning of the plasma exposure step the molecules HNMe2, CH4, HCN, and C2H2 were measured. After an extended period of plasma exposure, the reaction products CH4 and C2H2 were still present in the plasma. This change in the composition of the reaction products can be explained by an interplay of aspects including the plasma-surface interaction, the ALD surface reactions, and the reactions of products within the plasma. The species formed in the plasma (e.g., CHx radicals) can re-deposit on the surface and influence to a large extent the TaNx material composition and properties.
Anisotropic etching induced by surface energy driven agglomeration
Authors: Jung Jung Soon , Lutz Tarek , Boland John J.
Published: August 2011

The authors report on a previously unobserved anisotropic etching method in which a eutectic droplet created by heating a multilayer Au/Ge film is driven to form negative pits on the crystalline semiconductor surface. The etching process involves surface diffusion, evaporation, and pit formation. The shape of the pit is controlled by the underlying substrate symmetry. The surface morphology, crystal structure, and interfacial composition of the substrate (Si and Ge) were studied as a function of the thickness of the Au and Ge bilayer using scanning electron microscopy. The placement and size of the negative pits can be controlled by prepatterning the film.
Promoting the Middle East Peace Process by Changing Beliefs About Group Malleability
Authors: Halperin Eran , Russell Alexandra G. , Trzesniewski Kali H. , Gross James J. , Dweck Carol S.
Published: August 2011

A belief that the beliefs of other groups are changeable rather than fixed is conducive to negotiation.
MED12
, the
Mediator Complex Subunit 12
Gene, Is Mutated at High Frequency in Uterine Leiomyomas
Authors: Mäkinen Netta , Mehine Miika , Tolvanen Jaana , Kaasinen Eevi , Li Yilong , Lehtonen Heli J. , Gentile Massimiliano , Yan Jian , Enge Martin , Taipale Minna , Aavikko Mervi , Katainen Riku , Virolainen Elina , Böhling Tom , Koski Taru A. , Launonen Virpi , Sjöberg Jari , Taipale Jussi , Vahteristo Pia , Aaltonen Lauri A.
Published: August 2011

Uterine fibroids frequently harbor mutations in a specific gene that has been implicated in transcriptional regulation.
Impact of the national full herd depopulation policy on the recurrence of bovine tuberculosis in Irish herds, 2003 to 2005
Authors: Good M. , Clegg T. A. , Duignan A. , More S. J.
Published: August 2011

This study evaluated the impact of the Irish herd bovine tuberculosis (bTB) depopulation policy (depopulation, disinfection, contiguous testing and local badger removal where implicated) on the recurrence of bTB infection, by comparing the future risk in restocked herds following depopulation for either bTB or bovine spongiform encephalopathy (BSE) during 2003 to 2005. Each herd was assigned a ‘previous bTB risk’, based on bTB history during the five years before depopulation. Future bTB risk was estimated, using a multivariable Cox proportional hazard model for time‐to‐breakdown for each study herd, to identify risk factors associated with bTB. Future bTB risk varied significantly by reason for depopulation and previous bTB risk. Herds depopulated for bTB (by definition, at high bTB risk) were not significantly different from BSE herds with no or a low previous bTB risk. BSE herds with a high previous bTB risk were found to be at significantly greater future bTB risk. Herd bTB depopulation measures, as currently applied in Ireland, are shown to be effective in enabling herds to attain and retain bTB freedom following restocking. Based on the data presented, and consistent with current knowledge of the bTB epidemiology, local badger removal contributes to efforts to limit recurrence of bTB in Ireland.