bluuebunny/crossref_metadata_2025 huggingface dataset:
Isosceles trapezoid central configurations of the Newtonian four-body problem
Authors: Xie Zhifu
Published: June 2012

We use a simple direct and basic method to prove that there is a unique isosceles trapezoid central configuration of the planar Newtonian four-body problem when two pairs of equal masses are located at adjacent vertices of a trapezoid. Such isosceles trapezoid central configurations are an exactly one-dimensional family. Explicit expressions for masses are given in terms of the size of the quadrilateral.
Antimicrobial resistance to benzylpenicillin in invasive pneumococcal disease in Belgium, 2003–2010: the effect of altering clinical breakpoints
Authors: GOOSSENS M. C. , CATRY B. , VERHAEGEN J.
Published: June 2012

The Belgian data (2003–2010) for the European Antimicrobial Resistance Surveillance Network (EARS-Net) showed a significant decreasing trend in the proportion of penicillin non-susceptibleStreptococcus pneumoniae(9·4% to <1%) from blood and CSF isolates. We found that 75% of this decrease was explained by a change in Clinical and Laboratory Standards Institute (CLSI) breakpoints as the trend disappeared if only the new breakpoints were applied. Applying only European Committee on Antimicrobial Susceptibility Testing (EUCAST) breakpoints also resulted in a relatively stable proportion of penicillin non-susceptibility (average 5%), but this proportion was 7–13 times higher than with the new CLSI breakpoints. When the new CLSI breakpoints alone are used, fewer than 1% of bacteraemia isolates were penicillin non-susceptible during the entire period, but the proportion of non-susceptible meningitis isolates rose from 6·3% in 2003 to 15·9% between 2003 and 2010. Changing breakpoints should lead to retrospective analysis of historical data to minimize wrongly interpreting resistance trends.
DUMPING AS PRICE DISCRIMINATION: JANNACCONE’S CLASSIC THEORY BEFORE VINER
Authors: CANTONO SIMONA , MARCHIONATTI ROBERTO
Published: June 2012

Dumping actions and anti-dumping policies were regularly on the political agenda for several years in the pre-World War I period in Europe and the United States. In Italy, politics, economic circles, and scholars were engaged in debate on whether to protect sensitive industries threatened by sales below cost in their home markets, practiced by foreign competitors. Einaudi and his school of economics tackled the issue with several publications. In this paper we focus on Jannaccone’s essays, which he contributed to both a symposium in Riforma sociale in March 1914 and an issue in Rivista delle società commerciali in June 1914. Although we recognize that Viner (1923) theoretically systematized dumping in the wider framework of international trade, we nevertheless claim that the theoretical origin of dumping, in a context of imperfect competition, was Jannaccone’s essay. We show that Jannaccone proposed an early theory of dumping as an instance of the more general theory of price discrimination. He defined and classified dumping; he developed a static analysis of its profitability; he investigated the effects of dumping in both domestic and foreign markets; and he analyzed the effect of protectionism and its policy implications.
When the Problem is Beneath the Surface in OCD: The Cognitive Treatment of a Case of Pure Mental Contamination
Authors: Warnock-Parkes Emma , Salkovskis Paul M. , Rachman Jack
Published: June 2012

Background: Mental contamination is a phenomenon whereby people experience feelings of contamination from a non-physical contaminant. Rachman (2006) proposes that standard cognitive behavioural treatments (CBT) need to be adapted here and there is a developing empirical grounding supporting the concept, although suggestions on adapting treatment have yet to be tested. Method: A single case study is presented of a man with a 20-year history of severe treatment resistant Obsessive Compulsive Disorder (OCD) characterized by mental contamination following the experience of “betrayal”. He was offered two consecutive treatments: standard CBT and then (following disengagement with this) a cognitive therapy variant adapted for mental contamination. Clinician and patient rated OCD severity was measured at baseline and the start and end of both interventions. Results: Six sessions of high quality CBT were initially attended before refusal to engage with further sessions. There were no changes in OCD severity ratings across these sessions. A second course of cognitive therapy adapted for mental contamination was then offered and all 14 sessions and follow-ups were attended. OCD severity fell from the severe to non-clinical range across these sessions. Conclusions: The need to consider adapting standard treatments for mental contamination is suggested. Limitations and implications are discussed.
COLLECTIVE DESTIGMATIZATION AND EMANCIPATION THROUGH LANGUAGE IN 1960s QUÉBEC
Authors: Bouchard Gérard
Published: June 2012

In the history of Québec, the 1960s are known as the time of the Quiet Revolution. That decade is commonly referred to as a major watershed since it marked the onset of a spectacular economic, social, and cultural recovery of the Francophone (“French Canadian”) population. Previously, and for two centuries, Francophone Québec had been dominated by the British Empire and English Canada. Throughout the period, as a cultural minority, it had borne the brunt of ethnoracial stereotypes and had suffered from discrimination in the workplace. I seek to investigate one dimension of the destigmatizing process that unfolded in the 1960s by focusing on the discursive strategies devised by a group of young leftist intellectuals who argued that Francophone Québec needed a new national language as a condition of its full emancipation. My research focuses on major contradictions that this radical group had to confront: 1) they could have rejected the vernacular, stigmatized language (known asjoual) emblematic of the English domination, to adopt the Parisian French and thus become fully part of a great civilization, but by doing so they would have lapsed into another form of colonization since this superior language was considered as foreign and imposed at the expense of “authenticity”; and 2) they could have promotedjoualas the authentic language of the nation and worked to free it from stigma, but this would have come at the price of a “parochialization” of Québec culture. I show that these intellectuals failed to invent the collective myths that would have transcended this double bind and other contradictions. Finally, the paper compares Québec to other societies in the New World in order to better highlight the distinctiveness of this case.
ALL RESPONSES ARE NOT CREATED EQUAL
Authors: Bickerstaff Jovonne J.
Published: June 2012

This exploratory study makes a contribution to the literature on antiracism by analyzing how first-generation French Blacks of sub-Saharan African descent practice everyday antiracism. In doing so, it expands the demographic terrain of this research to highlight some particularities in the experience of everyday racism and antiracism for ethnoracial minorities ofimmigrant origins. In addition to experiencing forms of racism encountered by both immigrants and other native ethnoracial minorities, first-generation French Blacks (like other non-White first-generation Europeans), face symbolic exclusion from the national community and delegitimization of their claims to Europeanness. Examining their experiences sheds light on how race, immigration, and national identity intersect to generate unique experiences of racism and antiracism. This paper also contributes to our understanding of how social context shapes the range of everyday antiracist strategies at a person's disposal. Specifically, integrating Kasinitz et al.'s (2008) framework for categorizing incidents of racial discrimination and prejudice with Fleming et al.'s (2010) categorization of responses to stigmatization, I present an analysis of antiracist responses that takes into account both the nature of the relationship between the victim and the perpetrator of racism (i.e., impersonal vs. personal) and the social context in which the encounter occurs (e.g., school, work, public space, etc). In doing so, I highlight how the conditions of a given incident of racism or discrimination set constraints on the range of antiracist responses an individual can practically (or feasibly) employ.
WHAT WE FACE
Authors: Hirsch Nicole Arlette , Jack Anthony Abraham
Published: June 2012

While many sociological studies analyze the causes, conditions, and mechanisms perpetuating American racial inequality, the literature on how African Americans understand and explain these inequalities is less developed. Drawing on 150 interviews with middle-class and working-class African American men and women, this paper analyzes inductively how respondents define and conceptualize the most pressing obstacles facing their group when probed on this question. We find that middle- and working-class respondents alike identify the problem of racism as the most salient obstacle facing African Americans. Class differences appear with respect to what other obstacles are singled out as salient: while middle-class respondents focus on lack of racial solidarity among Blacks and economic problems (in this order), working-class respondents are more concerned with the fragility of the Black family followed by the lack of racial solidarity. This analysis discusses the relevance of considering how groups make sense of obstacles, and of racism and discrimination in particular, for the study of destigmatization and antiracist strategies of stigmatized minorities.
Public governance of healthcare in the United States: a transaction costs economics (TCE) analysis of the 2010 reform
Authors: SPITHOVEN ANTOON
Published: June 2012

This article aims to address the lack of transaction costs economics (TCE) studies in health economics. It provides a content analysis of ObamaCare and 25 lawsuits that challenge the 2010 reform. It shows that the cultural environment determines the strength of features of governance structures and in line with this the strength of their instruments. Following Williamson's TCE model of governance structures, the zero transaction costs criterion is supplanted by the remediableness criterion. Assuming that ObamaCare might be ruled to be constitutional, the regulation of healthcare is found to be a comparative efficient governance structure in addressing adverse selection. However, the TCE analysis also reveals that ObamaCare itself is subject to some flaws in efficiency and effectiveness, namely: unbalanced adaptation mechanisms, unbalanced incentives and weak enforcement devices.
Longitudinal differences of ionospheric vertical density distribution and equatorial electrodynamics
Authors: Yizengaw E. , Zesta E. , Moldwin M. B. , Damtie B. , Mebrahtu A. , Valladares C. E. , Pfaff R. F.
Published: June 2012

Accurate estimation of global vertical distribution of ionospheric and plasmaspheric density as a function of local time, season, and magnetic activity is required to improve the operation of space‐based navigation and communication systems. The vertical density distribution, especially at low and equatorial latitudes, is governed by the equatorial electrodynamics that produces a vertical driving force. The vertical structure of the equatorial density distribution can be observed by using tomographic reconstruction techniques on ground‐based global positioning system (GPS) total electron content (TEC). Similarly, the vertical drift, which is one of the driving mechanisms that govern equatorial electrodynamics and strongly affect the structure and dynamics of the ionosphere in the low/midlatitude region, can be estimated using ground magnetometer observations. We present tomographically reconstructed density distribution and the corresponding vertical drifts at two different longitudes: the East African and west South American sectors. Chains of GPS stations in the east African and west South American longitudinal sectors, covering the equatorial anomaly region of meridian ∼37°E and 290°E, respectively, are used to reconstruct the vertical density distribution. Similarly, magnetometer sites of African Meridian B‐field Education and Research (AMBER) and INTERMAGNET for the east African sector and South American Meridional B‐field Array (SAMBA) and Low Latitude Ionospheric Sensor Network (LISN) are used to estimate the vertical drift velocity at two distinct longitudes. The comparison between the reconstructed and Jicamarca Incoherent Scatter Radar (ISR) measured density profiles shows excellent agreement, demonstrating the usefulness of tomographic reconstruction technique in providing the vertical density distribution at different longitudes. Similarly, the comparison between magnetometer estimated vertical drift and other independent drift observation, such as from VEFI onboard Communication/Navigation Outage Forecasting System (C/NOFS) satellite and JULIA radar, is equally promising. The observations at different longitudes suggest that the vertical drift velocities and the vertical density distribution have significant longitudinal differences; especially the equatorial anomaly peaks expand to higher latitudes more in American sector than the African sector, indicating that the vertical drift in the American sector is stronger than the African sector.
Elevated iron to nitrogen recycling by mesozooplankton in the Northeast Atlantic Ocean
Authors: Giering Sarah L. C. , Steigenberger Sebastian , Achterberg Eric P. , Sanders Richard , Mayor Daniel J.
Published: June 2012

Low dissolved iron (DFe) concentrations limit primary production in most high‐nutrient low‐chlorophyll (HNLC) regions. Increased recycling of iron (Fe) relative to nitrogen (N) by zooplankton may help to sustain phytoplankton production in these conditions. We concurrently determined rates of DFe and ammonium (NH4+) recycling by natural mesozooplankton communities in HNLC conditions of the Northeast Atlantic. NH4+ excretion remained constant and ranged between 14.2–54.1 nmol NH4+ mg dry weight−1 h−1. Fe recycling ranged between 6–138 pmol DFe mg dry weight−1 h−1during the first hour and decreased thereafter, reflecting the transition from the loss of phytoplankton‐derived Fe to basal DFe excretion. Mesozooplankton‐driven nutrient recycling was estimated to support 6–59% and <1–13% of the respective phytoplankton requirements for DFe and N; DFe:N regeneration ratios were 5–26 times larger than those required by phytoplankton. Our data suggest that Fe recycling by grazing organisms has the potential to reduce the intensity of HNLC conditions.
Efficiency of solar wind energy coupling to the ionosphere
Authors: Guo Jianpeng , Feng Xueshang , Emery Barbara A. , Wang Yi
Published: June 2012

We present a statistical investigation into the variations of the ionospheric energy coupling efficiencies with the solar wind energy input, the interplanetary magnetic field (IMF) clock angle and the solar wind dynamic pressure. The ionospheric energy coupling efficiencies are defined as the ratios of the ionospheric energy deposition (namely auroral precipitation, Joule heating, and their total) to the solar wind energy input. We find that the ionospheric energy coupling efficiencies decrease exponentially with the solar wind energy input. Moreover, it is the same case under geomagnetic storm conditions. Our results also show that the energy coupling efficiencies are dependent on the IMF clock angle and almost independent of the solar wind dynamic pressure. These results will help us estimate and predict energy transfer from the solar wind to the thermosphere‐ionosphere system under extreme space weather conditions, particularly severe geomagnetic storms.
Transcriptional networks driving enhancer function in the CFTR gene
Authors: Kerschner Jenny L. , Harris Ann
Published: June 2012

A critical cis-regulatory element for the CFTR (cystic fibrosis transmembrane conductance regulator) gene is located in intron 11, 100 kb distal to the promoter, with which it interacts. This sequence contains an intestine-selective enhancer and associates with enhancer signature proteins, such as p300, in addition to tissue-specific TFs (transcription factors). In the present study we identify critical TFs that are recruited to this element and demonstrate their importance in regulating CFTR expression. In vitro DNase I footprinting and EMSAs (electrophoretic mobility-shift assays) identified four cell-type-selective regions that bound TFs in vitro. ChIP (chromatin immunoprecipitation) identified FOXA1/A2 (forkhead box A1/A2), HNF1 (hepatocyte nuclear factor 1) and CDX2 (caudal-type homeobox 2) as in vivo trans-interacting factors. Mutation of their binding sites in the intron 11 core compromised its enhancer activity when measured by reporter gene assay. Moreover, siRNA (small interfering RNA)-mediated knockdown of CDX2 caused a significant reduction in endogenous CFTR transcription in intestinal cells, suggesting that this factor is critical for the maintenance of high levels of CFTR expression in these cells. The ChIP data also demonstrate that these TFs interact with multiple cis-regulatory elements across the CFTR locus, implicating a more global role in intestinal expression of the gene.
Droplet size distribution in homogeneous isotropic turbulence
Authors: Perlekar Prasad , Biferale Luca , Sbragaglia Mauro , Srivastava Sudhir , Toschi Federico
Published: June 2012

We study the physics of droplet breakup in a statistically stationary homogeneous and isotropic turbulent flow by means of high resolution numerical investigations based on the multicomponent lattice Boltzmann method. We verified the validity of the criterion proposed by Hinze [AIChE J. 1, 289 (1955)] for droplet breakup and we measured the full probability distribution function of droplets radii at different Reynolds numbers and for different volume fractions. By means of a Lagrangian tracking we could follow individual droplets along their trajectories, define a local Weber number based on the velocity gradients, and study its cross-correlation with droplet deformation.
Refrigeration effect in a single-level quantum dot with thermal bias
Authors: Chi Feng , Zheng Jun , Liu Yu-Shen , Guo Yong
Published: June 2012

We theoretically study the heat generation in a quantum dot (QD) connected simultaneously to two reservoirs and a local phonon bath. We find that driven solely by an external thermal bias, the resonant tunneling electrons can absorb heat from the phonon bath to the QD that are held at the same temperature. This QD refrigerator also works well under the thermoelectric effect. At room temperature and large thermal bias, the magnitude of the heat current density is on the order of nW/cm2 in typical Ge/Si QD, of which the dot diameter is 40 nm with phonon frequency 5 × 1013 rad/s.
The curvature index and synchronization of dynamical systems
Authors: Chen Yen-Sheng , Chang Chien-Cheng
Published: June 2012

We develop a quantity, named the curvature index, for dynamical systems. This index is defined as the limit of the average curvature of the trajectory during evolution, which measures the bending of the curve on an attractor. The curvature index has the ability to differentiate the topological change of an attractor, as its alterations exhibit the structural changes of a dynamical system. Thus, the curvature index may indicate thresholds of some synchronization regimes. The Rössler system and a time-delay system are simulated to demonstrate the effectiveness of the index, respectively.
The np Rydberg series of boron monohydride: l-uncoupling and its evolution for intermediate principal quantum numbers n = 4 to n = 11
Authors: Viteri C. Ricardo , Grant Edward R.
Published: June 2012

Using optical-optical-optical triple-resonance spectroscopy, we assign rotational levels with N = 0–5 in the vibrationless, lower-n, p Rydberg states of 11BH. We apply the Hill and Van Vleck formulation for energy levels with l = 1 in a Hund's case intermediate between (b) and (d) to gauge the energy separating 1Π and 1Σ+ states with zero rotation for n = 4 − 11. This energy difference, A(l, ξ), represents the strength of the coupling, ξ, between the electron orbital angular momentum, l, and the internuclear axis, which determines the Λ-splitting constant, q0. The np series exhibits a large q0 that increases monotonically with n to reach a magnitude similar to the rotational constant, B0, by n = 9. For higher principal quantum numbers, Λ ceases to be a good quantum number, and l-uncoupling becomes virtually complete for n > 10.
Construction of orthogonal synchronized bi-directional field to enhance heating efficiency of magnetic nanoparticles
Authors: Chen Shih-Wei , Lai Jr-Jie , Chiang Chen-Li , Chen Cheng-Lung
Published: June 2012

Magnetic hyperthermia using magnetic nanoparticles (MNPs) has attracted considerable attention as one of the promising tumor therapy. The study has been developed under single magnetic field. Recently, we found that the immobile MNP may generate more heat under two synchronous ac magnetic fields than traditional single and circular polarized fields based on model simulation result. According to this finding we constructed an orthogonal synchronized bi-directional field (OSB field). The system contained two LC resonant inverters (L: inductor, C: capacitor) and both vertical and transverse ac magnetic fields were generated by two Helmholtz coils. To reduce the interference, the axis directional of two coils were arranged orthogonally. The experiments showed that the heating ability of aggregated MNPs is greatly enhanced under this newly designed OSB field without increasing the strength of magnetic field. The OSB field system provides a promising way for future clinical hyperthermia.
Liouvillian quasi-normal modes of Kerr-Newman black holes
Authors: Couch W. E. , Holder C. L.
Published: June 2012

The radial differential equations associated with separable perturbations of Kerr-Newman black holes are known to admit Liouvillian (closed-form) solutions for constrained frequencies and black hole parameters. In this paper, we show that the parameter constraints are satisfied exactly in the case of no rotation and thereby obtain a countable infinity of exact purely damped quasi-normal modes of fields on a Reissner-Nordstrom background at special values of the black hole charge-mass ratio. We show that with rotation the parameter constraints for Liouvillian quasi-normal modes are satisfied approximately in two distinct physical scenarios, where analytical approximations for angular eigenvalues are known. We arrive at functional expressions for quasi-normal frequencies and wave-functions in the case of near-extremal slow rotation and in a particular case of highly damped scalar modes of Kerr and Kerr-Newman. In the near-extremal case, our formulas extend a recent result of Hod to electromagnetic and gravitational perturbations.
Spin-spin relaxation of protons in ferrofluids characterized with a high-Tc superconducting quantum interference device-detected magnetometer in microtesla fields
Authors: Liao Shu-Hsien , Liu Chieh-Wen , Yang Hong-Chang , Chen Hsin-Hsien , Chen Ming-Jye , Chen Kuen-Lin , Horng Herng-Er , Wang Li-Min , Yang Shieh-Yueh
Published: June 2012

In this work, the spin-spin relaxation of protons in ferrofluids is characterized using a high-Tc SQUID-based detector in microtesla fields. We found that spin-spin relaxation rate is enhanced in the presence of superparamagnetic nanoparticles. The enhanced relaxation rates are attributed to the microscopic field gradients from magnetic nanoparticles that dephase protons’ spins nearby. The relaxation rates decrease when temperatures increase. Additionally, the alternating current magnetic susceptibility was inversely proportional to temperature. Those characteristics explained the enhanced Brownian motion of nanoparticles at high temperatures. Characterizing the relaxation will be helpful for assaying bio-molecules and magnetic resonance imaging in microtesla fields.
Simulation of a wire-cylinder-plate positive corona discharge in nitrogen gas at atmospheric pressure
Authors: Martins Alexandre A.
Published: June 2012

In this work, we are going to perform a simulation of a wire-cylinder-plate positive corona discharge in nitrogen gas, and compare our results with already published experimental results in air for the same structure. We have chosen to simulate this innovative geometry because it has been established experimentally that it can generate a thrust per unit electrode length transmitted to the gas of up to 0.35 N/m and is also able to induce an ion wind top velocity in the range of 8–9 m/s in air. In our model, the used ion source is a small diameter wire, which generates a positive corona discharge in nitrogen gas directed to the ground electrode, after which the generated positive ions are further accelerated in the acceleration channel between the ground and cathode. By applying the fluid dynamic and electrostatic theories, all hydrodynamic and electrostatic forces that act on the considered geometries will be computed in an attempt to theoretically confirm the generated ion wind profile and also the thrust per unit electrode length. These results are important to establish the validity of this simulation tool for the future study and development of this effect for practical purposes.
Cohesion enhancing effect of magnesium in aluminum grain boundary: A first-principles determination
Authors: Zhang Shengjun , Kontsevoi Oleg Y. , Freeman Arthur J. , Olson Gregory B.
Published: June 2012

The effect of magnesium on grain boundary cohesion in aluminum was investigated by means of first-principles calculations using the Rice-Wang model [Rice and Wang, Mater. Sci. Eng. A 107, 23 (1989)]. It is demonstrated that magnesium is a cohesion enhancer with a potency of −0.11 eV/atom. It is further determined through electronic structure and bonding character analysis that the cohesion enhancing property of magnesium is due to a charge transfer mechanism which is unusually strong and overcomes the negative result of the size effect mechanism. Consistent with experimental results, this work clarifies the controversy and establishes that Mg segregation does not contribute to stress corrosion cracking in Al alloys.
A new ab initio intermolecular potential energy surface and predicted rotational spectra of the Ne−H2S complex
Authors: Lei Jinping , Xiao Mengying , Zhou Yanzi , Xie Daiqian
Published: June 2012

We report a new three-dimensional ab initio intermolecular potential energy surface for the Ne−H2S complex with H2S monomer fixed at its experimental average structure. Using the supermolecular approach, the intermolecular potential energies were evaluated at CCSD(T) (coupled cluster with single and double and perturbative triple excitations) level with large basis sets including bond functions. The full counterpoise procedure was employed to correct the basis set superposition error. The planar T-shaped global minimum is located at the intermolecular distance of 3.51 Å with a well depth of 71.57 cm−1. An additional planar local minimum was found to be separated from the global minimum with an energy barrier of 23.11 cm−1. In addition, two first-order and one second-order saddle points were also located. The combined radial discrete variable representation/angular finite basis representation method and the Lanczos algorithm were employed to evaluate the rovibrational energy levels for eight isotopic species of the Ne−H2S complexes. The rotational transition frequencies for the eight isotopomers were also determined for the ground and first vibrational excited states, which are all in very good agreement with the available experimental values.
Weak magnetic field-enhanced glass formation in non-ferromagnetic Al-based alloys
Authors: Liu Zuming , Huang Liqing , Huang Baiyun , Wei Weifeng , Chen Zhilin , Huang Qun , Li Song , Liu Yong
Published: June 2012

We report that a transversal static magnetic field can effectively enhance glass formation of non-ferromagnetic Al-based alloys. This distinct phenomenon is mainly attributed to the Lorentz force and Joule heat generated from the magnetic field on moving alloy melts, which suppresses the diffusion of atoms and the nucleation in the alloy melts. It is anticipated that the experimental findings can provide some technical insights to the fabrication of amorphous non-ferromagnetic alloys.
Electrical properties of InAs1−xSbx and InSb nanowires grown by molecular beam epitaxy
Authors: Thelander Claes , Caroff Philippe , Plissard Sébastien , Dick Kimberly A.
Published: June 2012

Results of electrical characterization of Au nucleated InAs1−xSbx nanowires grown by molecular beam epitaxy are reported. An almost doubling of the extracted field effect mobility compared to reference InAs nanowires is observed for a Sb content of x = 0.13. Pure InSb nanowires on the other hand show considerably lower, and strongly diameter dependent, mobility values. Finally, InAs of wurtzite crystal phase overgrown with an InAs1−xSbx shell is found to have a substantial positive shift in threshold voltage compared to reference nanowires.
On integral length scales in anisotropic turbulence
Authors: Bewley Gregory P. , Chang Kelken , Bodenschatz Eberhard ,   (International Collaboration for Turbulence Research)
Published: June 2012

We found experimentally a dependence of the integral length scales of correlation functions measured in different directions in a turbulent flow on the velocity fluctuation anisotropy in those same directions. We derive invariants for anisotropic turbulence that is locally isotropic, and so a relationship between the velocity and length scales. The results emphasize the importance of defining the Reynolds number, which was about 480, in terms of scalar quantities instead of these scales. We also find that the normalized energy dissipation rate was approximately independent of the anisotropy.
Oxygen migration process in the interfaces during bipolar resistance switching behavior of WO3−x-based nanoionics devices
Authors: Yang Rui , Terabe Kazuya , Tsuruoka Tohru , Hasegawa Tsuyoshi , Aono Masakazu
Published: June 2012

Bipolar resistance switching (BRS) behavior and the effects of atmosphere (air, vacuum, O2 gas, or N2 gas) on BRS behavior occurred in the top and bottom interfaces in the M(top electrode)/WO3−x/Pt(bottom electrode) (M = Pt, Au) devices were investigated. Stable BRS only can be obtained in the interface with Pt electrode. And, the top Pt/WO3−x interface exhibited stable BRS only in an oxygen-rich atmosphere (air and O2 gas). In contrast, the bottom WO3−x/Pt interface showed stable BRS under any atmosphere. Based on the x-ray photoelectron spectroscopy measurement on Pt, Au/WO3−x interfaces, it is identified that the oxygen migration process during resistance switching mainly occurs between the Pt/WO3−x interface and Pt electrode.
Nanographene production from platelet carbon nanofiber by supercritical fluid exfoliation
Authors: Tomai Takaaki , Kawaguchi Yuji , Honma Itaru
Published: June 2012

Nanographene was synthesized from platelet carbon nanofiber by supercritical fluid (SCF) exfoliation without acid oxidation. During the exfoliation process, a progressive decrease in the number of layers was accompanied by the cutting of the basal plane. Raman spectroscopy was used to identify the quality of the samples, revealing that the defect density in the basal plane of the nanographene can be reduced to less than that of the starting material during SCF exfoliation.
Mechanism of non-metal catalytic growth of graphene on silicon
Authors: Hong Guo , Wu Qi-Hui , Ren Jianguo , Lee Shuit-Tong
Published: June 2012

Compared to preparation on metal substrates, graphene synthesis on non-metal surfaces is highly desirable to avoid the deleterious metallic effects in fabrication of electronic devices. However, study of graphene growth mechanism on non-metal surfaces is rare and little understood. Here, we report that few-layers graphene films can be grown directly on silicon-on-insulator surface. Furthermore, the graphene growth mechanism on non-metal surfaces is proposed as a surface reaction, adsorption, decomposition, and accumulation process.
Phase separation of co-evaporated ZnPc:C60 blend film for highly efficient organic photovoltaics
Authors: Zhou Ying , Taima Tetsuya , Miyadera Tetsuhiko , Yamanari Toshihiro , Kitamura Michinori , Nakatsu Kazuhiro , Yoshida Yuji
Published: June 2012

We demonstrate phase separation of co-evaporated zinc phthalocyanine (ZnPc) and fullerene (C60) for efficient organic photovoltaic cells. With introducing a poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) film and a crystalline copper iodide film on indium tin oxide, 20-nm-thick ZnPc film adopts a lying-down crystalline geometry with grain sizes of about 50 nm. This surface distributed with strong interaction areas and weak interaction areas enables the selective growth of ZnPc and C60 molecules during following co-evaporation, which not only results in a phase separation but also improve the crystalline growth of C60. This blend film greatly enhances the efficiencies in photocurrent generation and carrier transport, resulting in a high power conversion efficiency of 4.56% under 1 sun.
Position and energy-resolved particle detection using phonon-mediated microwave kinetic inductance detectors
Authors: Moore D. C. , Golwala S. R. , Bumble B. , Cornell B. , Day P. K. , LeDuc H. G. , Zmuidzinas J.
Published: June 2012

We demonstrate position and energy-resolved phonon-mediated detection of particle interactions in a silicon substrate instrumented with an array of microwave kinetic inductance detectors (MKIDs). The relative magnitude and delay of the signal received in each sensor allow the location of the interaction to be determined with ≲ 1mm resolution at 30 keV. Using this position information, variations in the detector response with position can be removed, and an energy resolution of σE = 0.55 keV at 30 keV was measured. Since MKIDs can be fabricated from a single deposited film and are naturally multiplexed in the frequency domain, this technology can be extended to provide highly pixelized athermal phonon sensors for ∼1 kg scale detector elements. Such high-resolution, massive particle detectors would be applicable to rare-event searches such as the direct detection of dark matter, neutrinoless double-beta decay, or coherent neutrino-nucleus scattering.
Core loss behavior in high frequency high power transformers—I: Effect of core topology
Authors: Bahmani M. A. , Agheb E. , Thiringer T. , Høidalen H. K. , Serdyuk Y.
Published: June 2012

This two-part paper presents an overview of core loss computations performed in both time and frequency domains in order to evaluate their behavior in single phase transformers with different core topologies. Moreover, the effects of non-sinusoidal waveforms on well-known core loss calculation methods are investigated with both analytically and finite element calculations. Three well-known configurations of transformers utilized in high frequency high power applications are investigated, namely, the core type, the shell type, and the matrix transformer. Based on the results obtained from a large number of FEM simulations for different operating conditions, the efficiencies of the transformers are compared in terms of distribution of magnetic flux density, loss density, total core loss, and weight. The analysis shows that for lower range of frequency and power, the shell type core could be the favorable option, and on the other hand, core type seems to be an appropriate solution for higher values of the operating frequency and nominal power.
Core loss behavior in high frequency high power transformers—II: Arbitrary excitation
Authors: Agheb E. , Bahmani M. A. , Høidalen H. K. , Thiringer T.
Published: June 2012

High frequency high power transformers used in power electronic converters are frequently subjected to non-sinusoidal excitations. The main purpose of this paper is to study the effects of some general arbitrary waveforms on magnetic core loss in these transformers. First, using well-known empirical equations, general expressions were derived based on the parameters of the waveforms. Second, the impacts of different orders of voltage harmonics were investigated. Finally, capabilities of nanocrystalline and amorphous magnetic materials were compared. It is shown that the loss inside the core is highly sensitive to the rise time and duty cycle of trapezoidal and rectangular waveforms, respectively. Furthermore, although amorphous materials have higher saturation flux density, the total core loss inside the transformer designed using nanocrystalline material is considerably lower than the similar transformer with amorphous materials.
Quasiclassical trajectory study of fast H-atom collisions with acetylene
Authors: Han Yong-Chang , Sharma Amit R. , Bowman Joel M.
Published: June 2012

Translationally hot H collisions with the acetylene are investigated using quasiclassical trajectory calculations, on a recent full-dimensional ab initio-based potential energy surface. Three outcomes are focused on: non-reactive energy transfer via prompt collisions, non-reactive energy transfer via the formation of the vinyl complex, and reactive chemical H-atom exchange, also via complex formation. The details of these outcomes are presented and correlated with the collision lifetime. Large energy transfer is found via complex formation, which can subsequently decay back to reactants, a non-reactive event, or to new products, a reactive event. For the present system, these two events are experimentally indistinguishable.
Water at hydrophobic interfaces delays proton surface-to-bulk transfer and provides a pathway for lateral proton diffusion
Authors: Zhang Chao , Knyazev Denis G. , Vereshaga Yana A. , Ippoliti Emiliano , Nguyen Trung Hai , Carloni Paolo , Pohl Peter
Published: June 2012

Fast lateral proton migration along membranes is of vital importance for cellular energy homeostasis and various proton-coupled transport processes. It can only occur if attractive forces keep the proton at the interface. How to reconcile this high affinity to the membrane surface with high proton mobility is unclear. Here, we tested whether a minimalistic model interface between an apolar hydrophobic phase (
n
-decane) and an aqueous phase mimics the biological pathway for lateral proton migration. The observed diffusion span, on the order of tens of micrometers, and the high proton mobility were both similar to the values previously reported for lipid bilayers. Extensive ab initio simulations on the same water/
n
-decane interface reproduced the experimentally derived free energy barrier for the excess proton. The free energy profile
G

H
+

adopts the shape of a well at the interface, having a width of two water molecules and a depth of 6 ± 2
RT
. The hydroniums in direct contact with
n
-decane have a reduced mobility. However, the hydroniums in the second layer of water molecules are mobile. Their in silico diffusion coefficient matches that derived from our in vitro experiments, (5.7 ± 0.7) × 10
-5
 cm
2
 s
-1
. Conceivably, these are the protons that allow for fast diffusion along biological membranes.
Cooperative coupling of cell-matrix and cell–cell adhesions in cardiac muscle
Authors: McCain Megan L. , Lee Hyungsuk , Aratyn-Schaus Yvonne , Kléber André G. , Parker Kevin Kit
Published: June 2012

Adhesion between cardiac myocytes is essential for the heart to function as an electromechanical syncytium. Although cell-matrix and cell–cell adhesions reorganize during development and disease, the hierarchical cooperation between these subcellular structures is poorly understood. We reasoned that, during cardiac development, focal adhesions mechanically stabilize cells and tissues during myofibrillogenesis and intercalated disc assembly. As the intercalated disc matures, we postulated that focal adhesions disassemble as systolic stresses are transmitted intercellularly. Finally, we hypothesized that pathological remodeling of cardiac microenvironments induces excessive mechanical loading of intercalated discs, leading to assembly of stabilizing focal adhesions adjacent to the junction. To test our model, we engineered μtissues composed of two ventricular myocytes on deformable substrates of tunable elasticity to measure the dynamic organization and functional remodeling of myofibrils, focal adhesions, and intercalated discs as cooperative ensembles. Maturing μtissues increased systolic force while simultaneously developing into an electromechanical syncytium by disassembling focal adhesions at the cell–cell interface and forming mature intercalated discs that transmitted the systolic load. We found that engineering the microenvironment to mimic fibrosis resulted in focal adhesion formation adjacent to the cell–cell interface, suggesting that the intercalated disc required mechanical reinforcement. In these pathological microenvironments, μtissues exhibited further evidence of maladaptive remodeling, including lower work efficiency, longer contraction cycle duration, and weakened relationships between cytoskeletal organization and force generation. These results suggest that the cooperative balance between cell-matrix and cell–cell adhesions in the heart is guided by an architectural and functional hierarchy established during development and disrupted during disease.
Cognitive shortcuts in causal inference
Authors: Fernbach Philip M. , Rehder Bob
Published: June 2012

The paper explores the idea that causality-based probability judgments are determined by two competing drives: one towards veridicality and one towards effort reduction. Participants were taught the causal structure of novel categories and asked to make predictive and diagnostic probability judgments about the features of category exemplars. We found that participants violated the predictions of a normative causal Bayesian network model because they ignored relevant variables (Experiments 1–3) and because they failed to integrate over hidden variables (Experiment 2). When the task was made easier by stating whether alternative causes were present or absent as opposed to uncertain, judgments approximated the normative predictions (Experiment 3). We conclude that augmenting the popular causal Bayes net computational framework with cognitive shortcuts that reduce processing demands can provide a more complete account of causal inference.
Plasma decay in air and O2 after a high-voltage nanosecond discharge
Authors: Aleksandrov N L , Anokhin E M , Kindysheva S V , Kirpichnikov A A , Kosarev I N , Nudnova M M , Starikovskaia S M , Starikovskii A Yu
Published: June 2012

This paper presents the results of experimental and theoretical studies of an afterglow in room temperature air and O2 excited by a high-voltage nanosecond discharge for pressures between 1 and 10 Torr. We measured time-resolved electron density by a microwave interferometer for initial electron densities in the range (2–3) × 1012 cm−3. Discharge uniformity was investigated by optical methods. The balance equations for charged particles and electron temperature were numerically solved to describe the temporal evolution of the densities of electrons and ions in the discharge afterglow. It was shown that the loss of electrons is governed by dissociative and three-body electron recombination with

ions under the conditions considered. Good agreement between the calculated and measured electron density histories could be obtained only when the rate of three-body recombination was increased by an order of magnitude and when the dependence of the recombination rate on electron temperature was changed. This could testify that the well-understood mechanism of three-body electron recombination with atomic ions could be noticeably modified in the case of molecular ions.
Experimental approaches for addressing fundamental biological questions in living, functioning cells with single molecule precision
Authors: Lenn Tchern , Leake Mark C.
Published: June 2012

In recent years, single molecule experimentation has allowed researchers to observe biological processes at the sensitivity level of single molecules in actual functioning, living cells, thereby allowing us to observe the molecular basis of the key mechanistic processes in question in a very direct way, rather than inferring these from ensemble average data gained from traditional molecular and biochemical techniques. In this short review, we demonstrate the impact that the application of single molecule bioscience experimentation has had on our understanding of various cellular systems and processes, and the potential that this approach has for the future to really address very challenging and fundamental questions in the life sciences.
Liver–intestine cadherin induction by epidermal growth factor receptor is associated with intestinal differentiation of gastric cancer
Authors: Sakamoto Naoya , Oue Naohide , Sentani Kazuhiro , Anami Katsuhiro , Uraoka Naohiro , Naito Yutaka , Oo Htoo Zarni , Hinoi Takao , Ohdan Hideki , Yanagihara Kazuyoshi , Aoyagi Kazuhiko , Sasaki Hiroki , Yasui Wataru
Published: June 2012

Gastric cancer (GC) is one of the most common malignancies worldwide. The epidermal growth factor receptor (EGFR) molecule is very important in GC progression. To examine the correlation between EGFR and GC‐related genes, we analyzed gene expression profiles of HT‐29 cells treated with EGFR ligands and identified six genes upregulated by epidermal growth factor (EGF) and transforming growth factor (TGF)‐α treatment. Among these, we focused on cadherin 17 (CDH17) encoding liver–intestine cadherin (LI‐cadherin). Expression of LI‐cadherin was induced by both EGF and TGF‐α, as detected by quantitative RT‐PCR and Western blot analysis. A luciferase assay showed that LI‐cadherin promoter activity was enhanced by EGF or TGF‐α in both HT‐29 cells and MKN‐74 GC cells. Immunohistochemical analysis of 152 GC cases showed that out of 58 LI‐cadherin‐positive cases, 24 (41%) cases were also positive for EGFR, whereas out of 94 LI‐cadherin‐negative cases, only 9 (10%) cases were positive for EGFR (P < 0.0001). Double‐immunofluorescence staining revealed that EGFR and LI‐cadherin were coexpressed. Significant correlation was found between LI‐cadherin expression and advanced T grade and N grade. Both EGFR and LI‐cadherin expression were more frequently found in GC cases with an intestinal mucin phenotype than in cases with a gastric mucin phenotype. These results indicate that, in addition to the known intestinal transcription factor caudal type homeobox 2, EGFR activation induces LI‐cadherin expression and participates in intestinal differentiation of GC.