bluuebunny/crossref_metadata_2025 huggingface dataset:
The role of gene–environment correlations and interactions in middle childhood depressive symptoms
Authors: Wilkinson Paul O. , Trzaskowski Maciej , Haworth Claire M. A. , Eley Thalia C.
Published: February 2013

Depression is known to be associated with a wide array of environmental factors. Such associations are due at least in part to genetic influences on both. This issue has been little explored with preadolescent children. Measures of family chaos and parenting style at age 9 and child depressive symptoms at age 12 were completed by 3,258 twin pairs from the Twins Early Development Study and their parents. Quantitative genetic modeling was used to explore common and unique genetic and environmental influences on both family environment and later depressive symptoms. Depressive symptoms at age 12 were significantly heritable. Moderate genetic effects influenced parenting style and family chaos at the age of 9, indicating gene–environment correlation. There were significant genetic correlations between family environment and depressive symptoms. There was some evidence of a Gene × Environment interaction, with stronger genetic effects on depressive symptoms for children with more suboptimal family environment. There was an Environment × Environment interaction, with effects of nonshared environment on depressive symptoms stronger for twins with more adverse parenting experiences. There is some evidence for gene–environment correlation between aspects of family environment in middle childhood and subsequent depressive symptoms. This suggests that one of the mechanisms by which genes lead to depressive symptoms may be by themselves influencing depressogenic environments.
Boys' serotonin transporter genotype affects maternal behavior through self-control: A case of evocative gene–environment correlation
Authors: Pener-Tessler Roni , Avinun Reut , Uzefovsky Florina , Edelman Shany , Ebstein Richard P. , Knafo Ariel
Published: February 2013

Self-control, involving processes such as delaying gratification, concentrating, planning, following instructions, and adapting emotions and behavior to situational requirements and social norms, may have a profound impact on children's adjustment. The importance of self-control suggests that parents are likely to modify their parenting based on children's ability for self-control. We study the effect of children's self-control, a trait partially molded by genetics, on their mothers' parenting, a process of evocative gene–environment correlation. Israeli 3.5-year-old twins (N = 320) participated in a lab session in which their mothers' parenting was observed. DNA was available from most children (N = 228). Mothers described children's self-control in a questionnaire. Boys were lower in self-control and received less positive parenting from their mothers, in comparison with girls. For boys, and not for girls, the serotonin transporter linked polymorphic region gene predicted mothers' levels of positive parenting, an effect mediated by boys' self-control. The implications of this evocative gene–environment correlation and the observed sex differences are discussed.
Observed positive parenting behaviors and youth genotype: Evidence for gene–environment correlations and moderation by parent personality traits
Authors: Oppenheimer Caroline W. , Hankin Benjamin L. , Jenness Jessica L. , Young Jami F. , Smolen Andrew
Published: February 2013

Gene–environment correlations (rGE) have been demonstrated in behavioral genetic studies, but rGE have proven elusive in molecular genetic research. Significant gene–environment correlations may be difficult to detect because potential moderators could reduce correlations between measured genetic variants and the environment. Molecular genetic studies investigating moderated rGE are lacking. This study examined associations between child catechol-O-methyltransferase genotype and aspects of positive parenting (responsiveness and warmth), and whether these associations were moderated by parental personality traits (neuroticism and extraversion) among a general community sample of third, sixth, and ninth graders (N = 263) and their parents. Results showed that parent personality traits moderated the rGE association between youths' genotype and coded observations of positive parenting. Parents with low levels of neuroticism and high levels of extraversion exhibited greater sensitive responsiveness and warmth, respectively, to youth with the valine/valine genotype. Moreover, youth with this genotype exhibited lower levels of observed anger. There was no association between the catechol-O-methyltransferase genotype and parenting behaviors for parents high on neuroticism and low on extraversion. Findings highlight the importance of considering moderating variables that may influence child genetic effects on the rearing environment. Implications for developmental models of maladaptive and adaptive child outcomes, and interventions for psychopathology, are discussed within a developmental psychopathology framework.
Changes in marital conflict and youths' responses across childhood and adolescence: A test of sensitization
Authors: Goeke-Morey Marcie C. , Papp Lauren M. , Cummings E. Mark
Published: February 2013

Although the sensitization hypothesis is fundamental to process-oriented explanations of the effects of marital conflict on children, few longitudinal tests of the theory's propositions have been conducted. Hierarchical linear modeling was used in this prospective, longitudinal study (n = 297 families) to assess changes in the dimensions of responding to conflict (i.e., emotional, cognitive, and behavioral) for 3 consecutive years in youths between the ages of 8 and 19 years. Moreover, to test the notion of sensitization, analyses were conducted to examine whether change in marital conflict predicted change in children's responding across middle childhood and adolescence. Supporting the sensitization hypothesis, increases in exposure to hostile marital conflict were associated with increases in children's negative emotionality, threat, self-blame, and skepticism about resolution. With a few exceptions, the effects were largely consistent for boys and girls and for younger and older children.
Intergenerational transmission of risk for social inhibition: The interplay between parental responsiveness and genetic influences
Authors: Natsuaki Misaki N. , Leve Leslie D. , Neiderhiser Jenae M. , Shaw Daniel S. , Scaramella Laura V. , Ge Xiaojia , Reiss David
Published: February 2013

To better understand mechanisms underlying the intergenerational transmission of social anxiety, we used a prospective adoption design to examine the roles of genetic influences (inferred from birth mothers' social phobia) and rearing environment (adoptive mothers' and fathers' responsiveness) on the development of socially inhibited, anxious behaviors in children between 18 and 27 months of age. The sample consisted of 275 adoption-linked families, each including an adopted child, adoptive parents, and a birth mother. Results indicated that children whose birth mothers met criteria for the diagnosis of social phobia showed elevated levels of observed behavioral inhibition in a social situation at 27 months of age if their adoptive mothers provided less emotionally and verbally responsive rearing environments at 18 months of age. Conversely, in the context of higher levels of maternal responsiveness, children of birth mothers with a history of social phobia did not show elevated levels of behavioral inhibition. These findings on maternal responsiveness were replicated in a model predicting parent reports of child social anxiety. The findings are discussed in terms of gene–environment interactions in the intergenerational transmission of social anxiety.
Coping with highly imbalanced datasets: A case study with definition extraction in a multilingual setting
Authors: DEL GAUDIO ROSA , BATISTA GUSTAVO , BRANCO ANTÓNIO
Published: February 2013

This paper addresses the task of automatic extraction of definitions by thoroughly exploring an approach that solely relies on machine learning techniques, and by focusing on the issue of the imbalance of relevant datasets. We obtained a breakthrough in terms of the automatic extraction of definitions, by extensively and systematically experimenting with different sampling techniques and their combination, as well as a range of different types of classifiers. Performance consistently scored in the range of 0.95–0.99 of area under the receiver operating characteristics, with a notorious improvement between 17 and 22 percentage points regarding the baseline of 0.73–0.77, for datasets with different rates of imbalance. Thus, the present paper also represents a contribution to the seminal work in natural language processing that points toward the importance of exploring the research path of applying sampling techniques to mitigate the bias induced by highly imbalanced datasets, and thus greatly improving the performance of a large range of tools that rely on them.
Negative Emotion Interference During a Synonym Matching Task in Pediatric Bipolar Disorder with and without Attention Deficit Hyperactivity Disorder
Authors: Passarotti Alessandra M. , Fitzgerald Jacklynn M. , Sweeney John A. , Pavuluri Mani N.
Published: February 2013

This study examined whether processing of emotional words impairs cognitive performance in acutely ill patients with pediatric bipolar disorder (PBD), with or without comorbid attention-deficit hyperactivity disorder (ADHD), relative to healthy controls (HC). Forty youths with PBD without ADHD, 20 youths with PBD and ADHD, and 29 HC (mean age = 12.97 ± 3.13) performed a Synonym Matching task, where they decided which of two probe words was the synonym of a target word. The three words presented on each trial all had the same emotional valence, which could be negative, positive, or neutral. Relative to HC both PBD groups exhibited worse accuracy for emotional words relative to neutral ones. This effect was greater with negative words and observed regardless of whether PBD patients had comorbid ADHD. In the PBD group without ADHD, manic symptoms correlated negatively with accuracy for negative words, and positively with reaction time (RT) for all word types. Our findings suggest a greater disruptive effect of emotional valence in both PBD groups relative to HC, reflecting the adverse effect of altered emotion processing on cognitive function in PBD. Future studies including an ADHD group will help clarify how ADHD symptoms may affect emotional interference independently of PBD. (JINS, 2013, 19, 1–12)
T-to-R and the Northern Subject Rule: questionnaire-based spatial, social and structural linguistics
Authors: BUCHSTALLER ISABELLE , CORRIGAN KAREN P. , HOLMBERG ANDERS , HONEYBONE PATRICK , MAGUIRE WARREN
Published: February 2013

Accents and dialects of English and Scots in Britain have been under active investigation for many decades, as reported through theSurvey of English Dialects(Ortonet al. 1962–71) and theLinguistic Atlas of Scotland(Matheret al. 1975–86), Wells’ three-volume compendium (1982), and a host of detailed studies of individual varieties. There are also welcome recent signs of the reintegration of variation data into theoretical discussion (see Henry 2002, Cornips & Corrigan 2005a and Trousdale & Adger 2007 for morphosyntax, as well as Anttila 2002 and Coetzee & Pater 2011 for phonology). Nonetheless, the precise structural, geolinguistic and sociolinguistic patterning of many features of vernacular Englishes in the UK is still largely unknown.
The health benefits of selective taxation as an economic instrument in relation to IHD and nutrition-related cancers
Authors: Holm Astrid L , Laursen Mai-Britt , Koch Maria , Jensen Jørgen D , Diderichsen Finn
Published: February 2013

Objective

The present study aimed to estimate the health benefits of selective taxation of healthy and unhealthy food commodities in relation to CVD and nutrition-related cancers.

Design

The potential health effects of a selective taxation scenario were estimated as changes in the burden of disease, measured by disability-adjusted life years, from health outcomes affected by the changes in food intake. The change in burden of a disease was calculated as the change in incidence of the disease due to a modified exposure level, using the potential impact fraction. Estimates of relative risk for the associations between various foods and relevant diseases were found through a literature search and used in the calculation of potential impact fractions.

Setting

The study was based in Denmark, estimating the health effects of a Danish selective taxation scenario.

Subjects

The potential health effects of selective taxation were modelled for the adult Danish population.

Results

Halving the rate of value-added tax on fruit and vegetables and increasing the tax on fats would result in moderate reductions in the burden of disease from IHD, ischaemic stroke, and colorectal, lung and breast cancer (0·4–2·4 % change). The largest effect could be obtained through increased intake of fruit and vegetables (0·9–2·4 %).

Conclusions

Applying selective taxation to healthy and unhealthy foods can moderately reduce the burden of disease in the Danish population.
Nicotine enhances antisaccade performance in schizophrenia patients and healthy controls
Authors: Petrovsky Nadine , Ettinger Ulrich , Quednow Boris B. , Landsberg Martin W. , Drees Judith , Lennertz Leonhard , Frommann Ingo , Heilmann Katharina , Sträter Birgitta , Kessler Henrik , Dahmen Norbert , Mössner Rainald , Maier Wolfgang , Wagner Michael
Published: February 2013

Nicotine has been proposed to be a cognitive enhancer, particularly in schizophrenia patients. So far, the published studies of nicotine effects on antisaccade performance in schizophrenia patients only tested participants who were deprived smokers. Thus, we aimed to test both smoking and non-smoking patients as well as healthy controls in order to extend previous findings. Moreover, we employed a paradigm using standard and delayed trials. We hypothesized that, if nicotine is a genuine cognitive enhancer, its administration would improve antisaccade performance both in smoking and non-smoking participants. A total of 22 patients with schizophrenia (12 smokers and 10 non-smokers) and 26 controls (14 smokers and 12 non-smokers) completed the study. The effects of a nicotine patch (14 mg for smokers, 7 mg for non-smokers) on antisaccade performance were tested in a randomized, double-blind, placebo-controlled, cross-over trial. Schizophrenia patients made significantly more antisaccade errors than controls (p = 0.03). Both patients and controls made fewer antisaccade errors in the delayed trials than in the standard trials (p < 0.0001). Nicotine significantly reduced antisaccade error rate in the standard trials, but not in the delayed trials (p = 0.02). Smoking status did not influence the nicotine effect on antisaccade error rate (p = 0.10) indicating an equal procognitive effect of nicotine in smokers and non-smokers. Overall the present findings indicate that beneficial effects of nicotine on antisaccade performance are not confined to smoking schizophrenia patients. Instead, the findings likely represent genuine nicotine-induced enhancement of cognitive performance.
Preferences for redistribution and pensions. What can we learn from experiments?
Authors: TAUSCH FRANZISKA , POTTERS JAN , RIEDL ARNO
Published: February 2013

Redistribution is an inevitable feature of collective pension schemes and economic experiments have revealed that most people have a preference for redistribution that is not merely inspired by self-interest. However, little is known on how these preferences interact with preferences for different pension schemes. In this paper, we review the experimental evidence on preferences for redistribution and suggest some links to redistribution through pensions. For that purpose we distinguish between three types of situations. The first deals with distributional preferences behind a veil of ignorance. In the second type of situation, individuals make choices in front of the veil of ignorance and know their position. Finally, we discuss situations in which income is determined by interdependent rather than individual choices. In the closing sections of the paper, we discuss whether and how these experimental results speak to the redistribution issues of pensions. For example, do they argue for or against mandatory participation? Should we have less redistribution and more actuarial fairness? How does this depend on the type of redistribution involved?
Depression, survival, and epidermal growth factor receptor genotypes in patients with metastatic non-small cell lung cancer
Authors: Pirl William F. , Traeger Lara , Greer Joseph A. , Jackson Vicki , Lennes Inga T. , Gallagher Emily , Sequist Lecia , Temel Jennifer S.
Published: February 2013

Objective:

Although depression appears to be associated with worse survival from cancer, the underlying mechanisms of this association are unknown. Tumor epidermal growth factor receptor (EGFR) genotype is a known predictor of survival in metastatic non-small cell lung cancer (NSCLC) and appears to be associated with depression. We hypothesized that tumor EGFR genotype may account for a relationship between depression and survival in this population. We investigated this possible relationship in a cohort of patients with metastatic NSCLC, in which we had previously demonstrated an association between depression and worse survival.

Method:

A cohort of 151 patients with newly diagnosed metastatic NSCLC were enrolled and followed in a randomized controlled trial of early palliative care. At enrollment, 150 had depression assessed with the Patient Health Questionnaire-9 (PHQ-9), and categorical scoring for major depressive syndrome (MDS) was used for analyses. Patients with tumor tissue available underwent EGFR genotyping. Associations with survival were tested using Cox proportional hazards models, adjusting for potential confounders.

Results:

Twenty-one patients (14.0%) met criteria for MDS. Forty-four patients (29.3%) had EGFR genotyping, and 17 (38.6%) of these harbored EGFR mutations. Patients with EGFR mutations had significantly lower PHQ-9 scores (p = 0.03), and none met criteria for depression. EGFR mutations were significantly associated with superior survival (p = 0.02). When both depression and EGFR genotype were simultaneously entered into the model, only EGFR mutations remained significantly associated with survival (p = 0.02), and the effect of depression was attenuated.

Significance of results:

Depression is associated with worse survival in metastatic NSCLC, and this relationship may be at least partially explained by tumor EGFR genotype. Further study into whether depression could be associated with specific biologic properties of cancer that vary by genotype is warranted.
Multimember Districts and the Substantive Representation of Women: An Analysis of Legislative Cosponsorship Networks
Authors: Clark Jennifer Hayes , Caro Veronica
Published: February 2013

Women's representation in elected and appointed positions is often seen as a matter of justice and equity (Burrell 1997). Beyond symbolic representation, many believe that a greater presence of women in institutions that have traditionally been controlled by men can facilitate the attention to issues that disproportionately affect women (Dahlerup 1988; Dodson and Carroll 1991; Kanter 1977). As the election of women has grown in the past decade, researchers have shown a renewed interest in understanding under what conditions women's descriptive representation can produce more effective substantive representation of women's interests. A number of feminist scholars argue that increasing the descriptive representation of women in legislatures is essential to remedy existing inequalities suffered by women (Mansbridge 1999). But electoral practices aimed at increasing women and minorities in office, such as majority-minority districts or gender quotas throughout European and Latin American countries, have produced varied results concerning the substantive representation of women and minority interests. Understanding the electoral and institutional features that strengthen or attenuate women's representation, therefore, merits further study.
Pushed Toward the Exit? How Female MPs Leave Parliament
Authors: Vanlangenakker Ine , Wauters Bram , Maddens Bart
Published: February 2013

Worldwide, politicians devote increasing attention to the sociodemographic representativeness of political institutions. The underrepresentation of specific groups (and of women in particular) in political institutions is a democratic problem (Phillips 1995). To counter the lack of representativeness of political institutions, measures have been adopted to increase the influx of female politicians in parliaments and governments. Among others, quota regulations have been implemented in several countries in recent years (Dahlerup 2007; Krook 2007).
What Does Evolution Have To Do with Legal Enclaves?
Authors: Crane-Seeber Jesse , Crane Betsy
Published: February 2013

While we applaud Hudson, Bowen, and Nielson (2011) for demonstrating the correlation between two modes of contemporary sexist oppression (inequality in family law and violence against women), we are concerned about how they embed a contested narrative of human evolution into otherwise straightforward findings. We argue that claims about human evolution are unnecessary to their argument, and, more importantly, that the version of feminist evolutionary analysis they describe is less feminist than it could be.
A Feminist Scientific Approach to the Analysis of Politics and Gender
Authors: McDermott Rose
Published: February 2013

One of the important perspectives that feminist analysis has brought to the study of politics is the value of the individual and the importance of capturing individual experience in our understanding of large social and political forces. Simple aggregation of individual experience can lose the richness of that reality. Yet the normative adherence to the critical appreciation of each person's life and experience need not prevent us from drawing inferences from patterns of behavior in order to help us intervene to improve the lot of those who suffer in the wake of systematic prejudice or discrimination.
The Limitations of Law as a Tool for Responding to Violence Against Women
Authors: DeLaet Debra L.
Published: February 2013

In their article, Hudson, Bowen, and Nielsen (2011) argue that inequities in family law codify an evolutionary legacy of male control over female reproduction that correlates with increased rates of violence against women. Their general argument is comprised of three fundamental premises. First, the authors provide empirical evidence indicating a relationship between inequities in family law, defined as “state regulation of marriage, parenthood, dissolution of marriage, custody of children, and transmission of goods across generations” (454), and levels of physical violence against women in particular societies. Second, the authors anchor their general argument in a feminist evolutionary analytic approach (FEAA). They contend that evolutionary forces are an ultimate cause of patriarchy and violence against women, even as they acknowledge the importance of more proximate causes of specific forms of violence against women. According to the authors, an FEAA approach can help explain “persistent patterns of patriarchy throughout human history” (464) and “…tells us that there is a strong evolutionary component to violence, and that its origin is male-female conflict over reproduction, and that these influences will be mirrored in human systems of family law” (468). Finally, the authors draw upon the two previous premises to build the third and most critical premise of their argument. Because the authors believe that evidence showing a correlation between inequities in family law and levels of physical violence are ultimately rooted in evolutionary dynamics, they conclude that “[s]ocieties that persist in safeguarding inequitable family law are societies built upon evolutionary male reproductive strategies of structural control and higher levels of coercion of women by men” (470).
Twin Pregnancies: Evaluation of Major Depression, Stress, and Social Support
Authors: Benute Glaucia R. G. , Nozzella Debora C. R. , Prohaska Cecilia , Liao Adolfo , de Lucia Mara C. S. , Zugaib Marcelo
Published: February 2013

Background: Twin pregnancies are at increased physiological and psychosocial risks. Objective: To investigate the prevalence of major depression in twin pregnancies and correlate with stress and social support. Method: The study included 51 pregnant women under specialized prenatal care who were evaluated by a Portuguese version of the semi-structured questionnaire Primary Care Evaluation of Mental Disorders (PRIME-MD) for Major Depression, and the Prenatal Psychosocial Profile (PPP) for evaluation of stress and social support. Results: Major depression was found in 33.3% of pregnant women, and prevailing symptoms were fatigue or loss of energy (100%), insomnia or hypersomnia (82.4%), changes in appetite (82.4%), decreased interest in daily activities (82.4%), and psychomotor agitation or retardation (82.4%). Among pregnant women who were diagnosed depressive, 76.5% also had a high level of stress and 47.1% complained about lack of social support. Statistical significance was found when correlating depression with perception of negative aspects of having twins and belief in significant body changes during pregnancy (p = .005 and .03, respectively). Marital status, occupation, and pregnancy planning were not significantly associated with the diagnosis of depression. Conclusion: Major depression occurs in one-third of pregnant women expecting twins and is associated with higher levels of stress and lack of social support. A multidisciplinary approach in these cases is fundamental to minimize further risks and complications.
Amino-acid-dependent main-chain torsion-energy terms for protein systems
Authors: Sakae Yoshitake , Okamoto Yuko
Published: February 2013

Many commonly used force fields for protein systems such as AMBER, CHARMM, GROMACS, OPLS, and ECEPP have amino-acid-independent force-field parameters for main-chain torsion-energy terms. Here, we propose a new type of amino-acid-dependent torsion-energy terms in the force fields. As an example, we applied this approach to AMBER ff03 force field and determined new amino-acid-dependent parameters for ψ (N-Cα-C-N) and ζ (Cβ-Cα-C-N) angles for each amino acid by using our optimization method, which is one of the knowledge-based approach. In order to test the validity of the new force-field parameters, we then performed folding simulations of α-helical and β-hairpin peptides, using the optimized force field. The results showed that the new force-field parameters gave structures more consistent with the experimental implications than the original AMBER ff03 force field.
Crystal asymmetry and low-angle grain boundary governed persistent photoinduced magnetization in small bandwidth manganites
Authors: Majumdar S. , Elovaara T. , Huhtinen H. , Granroth S. , Paturi P.
Published: February 2013

Persistent photo-induced magnetization (PPM) in low bandwidth manganite Pr1−xCaxMnO3 (PCMO) thin film is reported in the low hole doped regime (x = 0.1). X-ray diffraction, x-ray photoelectron spectroscopy, and magnetic measurements in dark and under illumination on the as-grown, vacuum, and oxygen annealed thin films of PCMO showed that the PPM effect is strongly dependent on the crystal symmetry, low angle grain boundaries, and the Mn valence states in the material. Compared with the as-grown and vacuum annealed film, the oxygen annealed film shows much less low-angle grain boundaries, higher crystal symmetry, and long range ferromagnetic (FM) ordering and in this sample PPM is not significant. These results clearly indicate that in this large band gap material PCMO, photo-induced FM interaction mainly arises due to improved domain-wall movement of the short range FM clusters. Significant PPM can be obtained for films with higher amount of grain boundaries, oxygen vacancies, and strain related defects.
Qualitative comparison of bremsstrahlung X-rays and 800 MeV protons for tomography of urania fuel pellets
Authors: Morris C. L. , Bourke M. , Byler D. D. , Chen C. F. , Hogan G. , Hunter J. F. , Kwiatkowski K. , Mariam F. G. , McClellan K. J. , Merrill F. , Morley D. J. , Saunders A.
Published: February 2013

We present an assessment of x-rays and proton tomography as tools for studying the time dependence of the development of damage in fuel rods. We also show data taken with existing facilities at Los Alamos National Laboratory that support this assessment. Data on surrogate fuel rods have been taken using the 800 MeV proton radiography (pRad) facility at the Los Alamos Neutron Science Center (LANSCE), and with a 450 keV bremsstrahlung X-ray tomography facility. The proton radiography pRad facility at LANSCE can provide good position resolution (<70 μm has been demonstrate, 20 μm seems feasible with minor changes) for tomography on activated fuel rods. Bremsstrahlung x-rays may be able to provide better than 100 μm resolution but further development of sources, collimation, and detectors is necessary for x-rays to deal with the background radiation for tomography of activated fuel rods.
Effective electron mean free path in TiN(001)
Authors: Chawla J. S. , Zhang X. Y. , Gall D.
Published: February 2013

The measured resistivity ρ of smooth stoichiometric epitaxial TiN(001) is 13 and 3.0 μΩ cm at 298 and 77 K for bulk layers but is 8 and 25 times higher when the layer thickness d is reduced to 2 nm. The increase in ρ with decreasing d is attributed to diffuse electron-surface scattering and is well described by the classical Fuchs-Sondheimer (F-S) model. This is unexpected because the F-S model is based on the nearly free electron model, while TiN exhibits a highly non-spherical Fermi surface and three bands crossing the Fermi-level. The measured room temperature effective electron mean free path λ for bulk scattering is 45 ± 4 nm, which is an order of magnitude larger than the free-electron prediction. This deviation is attributed to ∼93% of charge transport in TiN being due to two slightly filled bands which represent only 4% of conduction electrons. The F-S model is applicable to TiN because these two bands are nearly parabolic and nearly degenerate, yielding a single value for λ, which is estimated based on the published band structure to be 49 nm, in excellent agreement with the experimental 45 nm. These results demonstrate that the F-S model is applicable to metals with non-spherical Fermi-surfaces as long as the charge transport is dominated by a single (or multiple degenerate) band(s).
Origin of large recoverable strain in 0.94(Bi0.5Na0.5)TiO3-0.06BaTiO3 near the ferroelectric-relaxor transition
Authors: Simons Hugh , Daniels John E. , Glaum Julia , Studer Andrew J. , Jones Jacob L. , Hoffman Mark
Published: February 2013

Piezoceramics of composition 0.94(Bi0.5Na0.5)TiO3-0.06BaTiO3 demonstrate large recoverable strain at elevated temperature (T > 75 °C), which is absent at room temperature. In situ neutron diffraction was used to measure changes in the crystallographic and domain structures during electric field application at temperatures ranging from 25 °C to 100 °C. Quantitative evaluation of the ferroelastic domain volume fraction in the field-induced phases enabled calculation of the strain contribution from non-180° domain switching. The large recoverable strain is shown to be associated with the reversible nature of the phase transformation. These findings have implications to additional BNT-xBT-based composition and other relaxor ferroelectrics.
Effect of chiral property on hot phonon distribution and energy loss rate due to surface polar phonons in a bilayer graphene
Authors: Katti V. S. , Kubakaddi S. S.
Published: February 2013

Effect of chiral property on hot phonon distribution and hot electron energy loss rate due to surface polar phonons is investigated in a supported bilayer graphene. Hot phonon distribution Nq(ω0) with chiral property shows a new feature of appearance of a cusp. Interestingly, minimum of the cusp is shifting toward larger q and its width is increasing as electron concentration ns increases. The maximum value of Nq(ω0) is found to shift toward lower q with the increasing ns. This unusual behavior is not found in conventional two-dimensional electron gas (2DEG). The effect of chiral property on energy loss rate is found to be less significant. Hot phonon effect on energy loss rate is studied as a function of electron temperature and electron concentration for different substrates. It is found to reduce the energy loss rate significantly and the results are compared with those in conventional 2DEG. We believe that the magnitude of hot phonon effect depends both on dielectric constant of the substrate and surface polar phonon energy.
Ultrafast switching in wetting properties of TiO2/YSZ/Si(001) epitaxial heterostructures induced by laser irradiation
Authors: Bayati M. R. , Joshi S. , Molaei R. , Narayan R. J. , Narayan J.
Published: February 2013

We have demonstrated dark hydrophilicity of single crystalline rutile TiO2(100) thin films, in which rapid switching from a hydrophobic to a hydrophilic surface was achieved using nanosecond excimer laser irradiation. The TiO2/YSZ/Si(001) single crystalline heterostructures were grown by pulsed laser deposition and were subsequently irradiated by a single pulse of a KrF excimer laser at several energies. The wettability of water on the surfaces of the samples was evaluated. The samples were hydrophobic prior to laser annealing and turned hydrophilic after laser annealing. Superhydrophilic surfaces were obtained at higher laser energy densities (e.g., 0.32 J.cm−2). The stoichiometries of the surface regions of the samples before and after laser annealing were examined using XPS. The results revealed the formation of oxygen vacancies on the surface, which are surmised to be responsible for the observed superhydrophilic behavior. According to the AFM images, surface smoothening was greater in films that were annealed at higher laser energy densities. The samples exhibited hydrophobic behavior after being placed in ambient atmosphere. The origin of laser induced wetting behavior was qualitatively understood to stem from an increase of point defects near the surface, which lowered the film/water interfacial energy. This type of rapid hydrophobic/hydrophilic switching may be used to facilitate fabrication of electronic and photonic devices with novel properties.
Absolute measurement of low gas flow by means of the spectral analysis of the thermal wave
Authors: Rachalski A.
Published: February 2013

A new technique has been developed for determination of the very low gas flow velocity by means of the spectral analysis of the thermal waves. It is assumed that the transmitter signal is made of sine waves. By employing the Fourier analysis of the detector signals, the phase shifts of the relevant harmonic component of the frequency function were determined. The flow velocity has been obtained by a nonlinear regression analysis of the measured phase shifts values. This method allows for the flow of gas to be measured in a range from 5 to 500 cm/s.
Maxwell-Chern-Simons vortices on compact surfaces: Nonequivalence of the first and the second order equations
Authors: Han Jongmin , Kim Seongtag
Published: February 2013

In this paper we study the Maxwell-Chern-Simons-Higgs and the Chern-Simons-Higgs vortices on a compact Riemann surface. We establish the existence of a solution of the static Maxwell-Chern-Simons-Higgs vortex equations, which is a minimizer of the static energy functional. This shows the nonequivalence of the first and the second order Maxwell-Chern-Simons-Higgs vortex equations. The nonequivalence is also proved for the Chern-Simons-Higgs vortices by verifying the Chern-Simons limit.
Intrinsic degradation mechanism of nearly lattice-matched InAlN layers grown on GaN substrates
Authors: Perillat-Merceroz Guillaume , Cosendey Gatien , Carlin Jean-François , Butté Raphaël , Grandjean Nicolas
Published: February 2013

Thanks to its high refractive index contrast, band gap, and polarization mismatch compared to GaN, In0.17Al0.83N layers lattice-matched to GaN are an attractive solution for applications such as distributed Bragg reflectors, ultraviolet light-emitting diodes, or high electron mobility transistors. In order to study the structural degradation mechanism of InAlN layers with increasing thickness, we performed metalorganic vapor phase epitaxy of InAlN layers of thicknesses ranging from 2 to 500 nm, on free-standing (0001) GaN substrates with a low density of threading dislocations, for In compositions of 13.5% (layers under tensile strain), and 19.7% (layers under compressive strain). In both cases, a surface morphology with hillocks is initially observed, followed by the appearance of V-defects. We propose that those hillocks arise due to kinetic roughening, and that V-defects subsequently appear beyond a critical hillock size. It is seen that the critical thickness for the appearance of V-defects increases together with the surface diffusion length either by increasing the temperature or the In flux because of a surfactant effect. In thick InAlN layers, a better (worse) In incorporation occurring on the concave (convex) shape surfaces of the V-defects is observed leading to a top phase-separated InAlN layer lying on the initial homogeneous InAlN layer after V-defects coalescence. It is suggested that similar mechanisms could be responsible for the degradation of thick InGaN layers.
Development of a molecular-dynamics-based cluster-heat-capacity model for study of homogeneous condensation in supersonic water-vapor expansions
Authors: Borner Arnaud , Li Zheng , Levin Deborah A.
Published: February 2013

Supersonic expansions to vacuum produce clusters of sufficiently small size that properties such as heat capacities and latent heat of evaporation cannot be described by bulk vapor thermodynamic values. In this work the Monte-Carlo Canonical-Ensemble (MCCE) method was used to provide potential energies and constant-volume heat capacities for small water clusters. The cluster structures obtained using the well-known simple point charge model were found to agree well with earlier simulations using more rigorous potentials. The MCCE results were used as the starting point for molecular dynamics simulations of the evaporation rate as a function of cluster temperature and size which were found to agree with unimolecular dissociation theory and classical nucleation theory. The heat capacities and latent heat obtained from the MCCE simulations were used in direct-simulation Monte-Carlo of two experiments that measured Rayleigh scattering and terminal dimer mole fraction of supersonic water-jet expansions. Water-cluster temperature and size were found to be influenced by the use of kinetic rather than thermodynamic heat-capacity and latent-heat values as well as the nucleation model.
Qualitative and quantitative evaluation of thin-film solar cells using solar cell local characterization
Authors: Wagner J.-M. , Carstensen J. , Schütt A. , Föll H.
Published: February 2013

The light-beam-induced current-based CELLO measurement technique (solar CELl LOcal characterization), originally developed for wafer-based silicon solar cells, can successfully be applied to thin-film solar cells, provided that contacting of a single cell is possible. This is shown exemplarily for several crystalline silicon on glass samples, having varying quality with respect to photocurrent extraction, series resistance, and power losses. For the latter, a comparison with results obtained from dark lock-in thermography gives quantitative agreement, provided that the cells are not severely shunted.
Dose enhancing behavior of hydrothermally grown Eu-doped SnO2 nanoparticles
Authors: Sánchez Zeferino R. , Pal U. , Meléndrez R. , Durán-Muñoz H. A. , Barboza Flores M.
Published: February 2013

Hydrothermally grown SnO2 and SnO2:Eu nanoparticles of 4–11 nm size range were analyzed by photoluminescence (PL) and therrmoluminescence (TL) spectroscopy to study the effect of Eu-doping on their emission behaviors. It has been observed that most of the incorporated Eu3+ ions remain at the interstitial sites of SnO2 lattice. High Eu-contents in the nanoparticles generate lattice deformation, formation of Eu3+/Eu0 clusters at interstitial sites, or segregation to their surfaces. Formation of Eu clusters at interstitial sites enhances electronic defect density in the crystal lattice, reorganizes carrier trapping centers, and modifies their activation energies. Room temperature PL emission and beta-irradiated TL dose response of SnO2 nanoparticles enhance significantly when doped with 0.5 and 1.0 mol. % nominal of Eu3+, respectively, opening up their possibilities of applications in bio-imaging and radiation therapy. Possible mechanisms of enhanced PL and TL responses of the samples have been discussed.
Roles of core-shell and δ-ray kinetics in layered BN α-voltaic efficiency
Authors: Melnick Corey , Kaviany Massoud , Kim Moo-Hwan
Published: February 2013

α-voltaics harvest electron-hole pairs created as energetic α particles collide with and ionize electrons in a semiconductor, creating δ-rays. After ionization, charged pair production continues through δ-ray impact ionization events and the Auger relaxation of core-shell holes created through K-shell ionization events. Secondary ionization events are quantified using the TPP-2M model, the fraction of K-shell ionization events is determined using the energy-loss Coulomb-repulsion perturbed-stationary-state relativistic theory, and the relaxation of the resulting holes is treated with a fully ab initio approach using multiple Fermi golden rule calculations for ranges of carrier concentrations and temperatures. The limiting rate is 15 ns−1 for small carrier concentrations and high temperatures, as compared to the radiative core-shell relaxation rate estimated here at 20 ns−1, indicating that Auger modes contribute significantly. Moreover, the K-shell ionization events are shown to dominate for low energy α particles and vanish for high energy ones. Thus, the efficiency loss due to energy dissipation in the fuel layer is mitigated, which is demonstrated by the analysis of a layered fuel-voltaic device with an efficiency from 20% to 14% for fuel layers between 5 and 10 μm thick. The design of a α-voltaic integrated with a thermoelectric generator is suggested for improved efficiency and the system-level mitigation of radiation damage and geometric inefficiency.
Optimization of Hall bar response to localized magnetic and electric fields
Authors: Nabaei V. , Rajkumar R. K. , Manzin A. , Kazakova O. , Tzalenchuk A.
Published: February 2013

The present paper investigates the influence of localized magnetic and electric fields, produced by a magnetic scanning tip, on the response of high-mobility two-dimensional electron gas in a Hall bar geometry. We have developed a comprehensive numerical model, validated it by experiment and found the optimal design for magnetic sensing and limitation of perturbing effects due to electric field. This approach can be straightforwardly extended to the design of sensors for the detection of charged magnetic nanoparticles.
Response to “Comment on ‘On the theoretical determination of the Prigogine-Defay ratio in glass transition”’ [J. Chem. Phys. 138, 067101 (2012)]
Authors: Schmelzer Jürn W. P.
Published: February 2013

It is shown that the claims of the authors of the Comment on “On the theoretical determination of the Prigogine-Defay ratio in glass transition” [Tropin et al., J. Chem. Phys. 136, 124502 (2012)]10.1063/1.3694531 are not correct. Three different methods are briefly reviewed leading to the same consequence that the experimentally determined values of the Prigogine-Defay ratio may have values larger than one even for glass-forming systems which can be described by only one structural order parameter.
Sub-volt broadband hybrid plasmonic-vanadium dioxide switches
Authors: Joushaghani Arash , Kruger Brett A. , Paradis Suzanne , Alain David , Stewart Aitchison J. , Poon Joyce K. S.
Published: February 2013

The insulator-metal phase transition of a correlated-electron material, vanadium dioxide, is used to demonstrate electrically controlled, compact, broadband, and low voltage plasmonic switches. The devices are micron-scale in length and operate near a wavelength of 1550 nm. The switching bandwidths exceed 100 nm and 400 mV is sufficient to attain extinction ratios in excess of 20 dB. The results illustrate the promise of using phase transition materials for efficient and ultra-compact plasmonic switches and modulators.
Hybrid diodes based on n-type Ge and conductive polymer doped by graphene oxide sheets with and without reduction treatment
Authors: Zeng Jian-Jhou , Lin Yow-Jon
Published: February 2013

The authors present a hybrid diode based on n-type Ge and poly(3,4-ethylenedioxythiophene) doped with poly(4-styrenesulfonate) (PEDOT:PSS) having the reduced graphene oxide (RGO) or graphene oxide (GO) sheets. It is found that conductivity of RGO-doped PEDOT:PSS films increases with increasing the reduction temperature of GO sheets. The improvement of electrical conductivity is considered to mainly come from the carrier mobility enhancement. In addition, the ideality factor of n-type Ge/RGO-doped PEDOT:PSS diodes decreases with increasing the reduction temperature of GO sheets. The device-performance improvement originates from high-mobility hole transport combined with long-lifetime electron trapping in the RGO-doped PEDOT:PSS film. However, GO doping may lead to decreased conductivity, owing to the large number of the oxygen-related defects in GO sheets. The device-performance degradation originates from low-mobility hole transport combined with short-lifetime electron trapping in the GO-doped PEDOT:PSS film.
The possibility of giant dielectric materials for multilayer ceramic capacitors
Authors: Ishii Tatsuya , Endo Makoto , Masuda Kenichiro , Ishida Keisuke
Published: February 2013

There have been numerous reports on discovery of giant dielectric permittivity materials called internal barrier layer capacitor in the recent years. We took particular note of one of such materials, i.e., BaTiO3 with SiO2 coating. It shows expressions of giant electric permittivity when processed by spark plasma sintering. So we evaluated various electrical characteristics of this material to find out whether it is applicable to multilayer ceramic capacitors. Our evaluation revealed that the isolated surface structure is the sole cause of expressions of giant dielectric permittivity.
Identifying the efficient inter-conversion between singlet and triplet charge-transfer states by magneto-electroluminescence study
Authors: Chen Ping , Peng Qiming , Yao Liang , Gao Na , Li Feng
Published: February 2013

Using the magneto-electroluminescence (MEL) as a tool, we demonstrated the efficient inter-conversion between singlet and triplet charge-transfer (CT) states in exciplex-based organic light-emitting diodes (OLEDs). Results show that the MEL of exciplex-based device is larger than that of exciton-based device by a factor of 3.2. The emission of exciplex-based devices comes from the direct intermolecular electron-hole pair recombination and their spin exchange energy is much smaller, which causes the efficient inter-conversion between singlet and triplet states. This argument was supported by the consistent evolutions of the MEL and EL spectra versus applied bias and donor concentrations. Finally, the bandgap effects on the MEL as well as the external quantum efficiency of exciplex-based devices were discussed. Our findings of MEL may offer a feasible way to unravel underlying mechanisms that limit the EL efficiency in the OLEDs.