bluuebunny/crossref_metadata_2025 huggingface dataset:
Implicit Affiliation Motive Predicts Correct Intuitive Judgment
Authors: Quirin Markus , Düsing Rainer , Kuhl Julius
Published: February 2013

Previous research demonstrated that affiliation primes facilitate intuitive thought ( Kuhl & Kazén, 2008 ). We investigated whether trait tendencies toward affiliation also predict intuitive thought. Thirty-nine students filled in the operant motive test for the assessment of social motives, a variant of the Thematic Apperception Test, and corresponding self-report scales. Then, 9 months later, participants engaged in a remote associates task where they intuitively indicated whether three words are semantically related. As expected, the implicit affiliation motive significantly predicted the accuracy of identifying related word triads, though neither implicit power and achievement motives, nor explicit motives did so.
Psychopathic Traits in Youth and Associations with Temperamental Features
Authors: Roose Annelore , Bijttebier Patricia , Van der Oord Saskia , Claes Laurence , Lilienfeld Scott O.
Published: February 2013

The present study aims to disentangle motivational and self-regulatory pathways to psychopathic traits in youth with severe antisocial behavior. The associations between self-reported psychopathic traits and indices derived from a laboratory measure assessing fear sensitivity and self-regulation were evaluated. Low scores on fear sensitivity and self-regulation were related to high scores on the self-reported Callous/Unemotional factor of psychopathic traits and the Callousness dimension in particular. The present study provides at least partial evidence for both motivational (low-fear hypothesis; Lykken, 1995 ) and self-regulatory (response modulation hypothesis; Patterson & Newman, 1993 ) accounts of psychopathic traits in youth.
Self-Protection Versus Disease Avoidance
Authors: Prokop Pavol , Fančovičová Jana
Published: February 2013

Predators and pathogens are powerful natural selection tools that influence the evolution of two domain-specific management systems: self-protection and disease avoidance. Both systems are activated by specific ecological conditions and protect humans against physical harm or disease transmission. The perception of predators is associated with fear, and the perception of disease-relevant animals is associated with disgust. Fear of predators negatively correlated with the perceived physical condition of participants, suggesting that the self-protection system is activated particularly in people who are more vulnerable to predation threat. People vulnerable to infectious diseases rated predators as more dangerous, suggesting that the disease-avoidance system activates behavior-reducing contact with harmful animals. Females had a higher score in terms of fear, disgust, and perceived danger in particular when considering animals that pose physical harm and/or a disease threat. Our results support the adaptation view, suggesting that the self-protection and disease-avoidance systems are domain specific, and that both have been shaped by natural selection in order to protect humans against harmful animals or events.
The multifaceted role of mTORC1 in the control of lipid metabolism
Authors: Ricoult Stéphane J H , Manning Brendan D
Published: February 2013

The mechanistic target of rapamycin is a protein kinase that, as part of the mechanistic target of rapamycin complex 1 (mTORC1), senses both local nutrients and, through insulin signalling, systemic nutrients to control a myriad of cellular processes. Although roles for mTORC1 in promoting protein synthesis and inhibiting autophagy in response to nutrients have been well established, it is emerging as a central regulator of lipid homeostasis. Here, we discuss the growing genetic and pharmacological evidence demonstrating the functional importance of its signalling in controlling mammalian lipid metabolism, including lipid synthesis, oxidation, transport, storage and lipolysis, as well as adipocyte differentiation and function. Defining the role of mTORC1 signalling in these metabolic processes is crucial to understanding the pathophysiology of obesity and its relationship to complex diseases, including diabetes and cancer.
Contributions of dendritic cells and macrophages to intestinal homeostasis and immune defense
Authors: Farache Julia , Zigmond Ehud , Shakhar Guy , Jung Steffen
Published: February 2013

Intestinal mononuclear phagocytes have collectively emerged as key players in the maintenance of gut homeostasis, the development of gut inflammation and its resolution. Moreover, recent intense research efforts of many laboratories have revealed evidence for critical labor division between lamina propria‐resident CD103+ dendritic cells and CX3CR1+ macrophages. In depth understanding of the respective activities of these cells in the mucosal landscape might pave the way for novel treatments of inflammatory bowel disorders (IBD).
Differential modulation of EAE by α9*‐ and β2*‐nicotinic acetylcholine receptors
Authors: Simard Alain R , Gan Yan , St‐Pierre Stéphanie , Kousari Ariana , Patel Varun , Whiteaker Paul , Morley Barbara J , Lukas Ronald J , Shi Fu‐Dong
Published: February 2013

Nicotine is a potent inhibitor of the immune response and is protective against experimental autoimmune encephalomyelitis (EAE). Initial studies suggested that the cholinergic system modulates inflammation via the α7‐nicotinic acetylcholine receptor (nAChR) subtype. We recently have shown that effector T cells and myeloid cells constitutively express mRNAs encoding nAChR α9 and β2 subunits and found evidence for immune system roles for non‐α7‐nAChRs. In the present study, we assessed the effects of nAChR α9 or β2 subunit gene deletion on EAE onset and severity, with or without nicotine treatment. We report again that disease onset is delayed and severity is attenuated in nicotine‐treated, wild‐type mice, an effect that also is observed in α9 subunit knock‐out (KO) mice irrespective of nicotine treatment. On the other hand, β2 KO mice fail to recover from peak measures of disease severity regardless of nicotine treatment, despite retaining sensitivity to nicotine's attenuation of disease severity. Prior to disease onset, we found significantly less reactive oxygen species production in the central nervous system (CNS) of β2 KO mice, elevated proportions of CNS myeloid cells but decreased ratios of CNS macrophages/microglia in α9 or β2 KO mice, and some changes in iNOS, TNF‐α and IL‐1β mRNA levels in α9 KO and/or β2 KO mice. Our data thus suggest that β2*‐ and α9*‐nAChRs, in addition to α7‐nAChRs, have different roles in endogenous and nicotine‐dependent modulation of immune functions and could be exploited as therapeutic targets to modulate inflammation and autoimmunity.
Entamoeba histolytica: identification of thioredoxin-targeted proteins and analysis of serine acetyltransferase-1 as a prototype example
Authors: Schlosser Sarah , Leitsch David , Duchêne Michael
Published: February 2013

Entamoeba histolytica, the causative agent of amoebiasis, possesses the dithiol-containing redox proteins Trx (thioredoxin) and TrxR (Trx reductase). Both proteins were found to be covalently modified and inactivated by metronidazole, a 5-nitroimidazole drug that is commonly used to treat infections with microaerophilic protozoan parasites in humans. Currently, very little is known about enzymes and other proteins participating in the Trx-dependent redox network of the parasite that could be indirectly affected by metronidazole treatment. On the basis of the disulfide/dithiol-exchange mechanism we constructed an active-site mutant of Trx, capable of binding interacting proteins as a stable mixed disulfide intermediate to screen the target proteome of Trx in E. histolytica. By applying Trx affinity chromatography, two-dimensional gel electrophoresis and MS, peroxiredoxin and 15 further potentially redox-regulated proteins were identified. Among them, EhSat1 (E. histolytica serine acetyltransferase-1), an enzyme involved in the L-cysteine biosynthetic pathway, was selected for detailed analysis. Binding of Trx to EhSat1 was verified by Far-Western blot analysis. Trx was able to restore the activity of the oxidatively damaged EhSat1 suggesting that the TrxR/Trx system protects sensitive proteins against oxidative stress in E. histolytica. Furthermore, the activity of peroxiredoxin, which is dependent on a functioning TrxR/Trx system, was strongly reduced in metronidazole-treated parasites.
The P-body component USP52/PAN2 is a novel regulator of HIF1A mRNA stability
Authors: Bett John S. , Ibrahim Adel F. M. , Garg Amit K. , Kelly Van , Pedrioli Patrick , Rocha Sonia , Hay Ronald T.
Published: February 2013

HIF1A (hypoxia-inducible factor 1α) is the master regulator of the cellular response to hypoxia and is implicated in cancer progression. Whereas the regulation of HIF1A protein in response to oxygen is well characterized, less is known about the fate of HIF1A mRNA. In the present study, we have identified the pseudo-DUB (deubiquitinating enzyme)/deadenylase USP52 (ubiquitin-specific protease 52)/PAN2 [poly(A) nuclease 2] as an important regulator of the HIF1A-mediated hypoxic response. Depletion of USP52 reduced HIF1A mRNA and protein levels and resulted in reduced expression of HIF1A-regulated hypoxic targets due to a 3′-UTR (untranslated region)-dependent poly(A)-tail-length-independent destabilization in HIF1A mRNA. MS analysis revealed an association of USP52 with several P-body (processing body) components and we confirmed further that USP52 protein and HIF1A mRNA co-localized with cytoplasmic P-bodies. Importantly, P-body dispersal by knockdown of GW182 or LSM1 resulted in a reduction of HIF1A mRNA levels. These data uncover a novel role for P-bodies in regulating HIF1A mRNA stability, and demonstrate that USP52 is a key component of P-bodies required to prevent HIF1A mRNA degradation.
Cultural Considerations in Serving Children With ASD and Their Families: Asian American Perspective
Authors: Seung HyeKyeung
Published: February 2013

The author of this article reviews cultural differences that will guide clinicians when providing services to Asian American children with autism and discusses culturally based clinical issues/suggestions for working successfully with Asian American families. Theory is followed using examples from three sources: (a) the author’s direct experience, (b) a Korean parent support group, and (c) a one-time open dialogue event among Asian parents of children with autism and professionals who serve them.
Translating Between Research and Practice in Serving Infants at Risk for ASD
Authors: Watson Linda R. , Crais Elizabeth R.
Published: February 2013

In research studies, we are now able to identify many infants who are at risk for later diagnoses of autism spectrum disorders (ASD) as early as 12 months of age. The authors are part of a research team developing and testing a tool for early identification and also testing the efficacy of an early intervention for infants at risk for ASD. Challenges encountered in this research highlight some of the issues that speech-language pathologists and other professionals serving the infant/toddler population may face. This article uses our research team’s experiences to raise some of the ethical and practical concerns regarding translating from research to practice in early identification for this population, and the potential implications for early intervention policies and services.
The optimization of super-high resolution frequency measurement techniques based on phase quantization regularities between any frequencies
Authors: Li Zhiqi , Zhou Wei , Zhou Hui , Zhang Xueping , Zhao Jie
Published: February 2013

Step phase quantization regularity between different nominal frequency signals is introduced in this paper. Based on this regularity, an optimized high resolution frequency measurement technique is presented. The key features and issues of phase quantization characteristics and measurements are described. Based on the relationship between the same or multiple nominal signals with a certain differences, the resolution of frequency measurements is developed and the range is widened. Several measurement results are provided to support the concepts with experimental evidence. The resolution of frequency measurement can reach 10−12 (s−1) over a wide range or higher for specific frequency signals.
Multi-fault clustering and diagnosis of gear system mined by spectrum entropy clustering based on higher order cumulants
Authors: Shao Renping , Li Jing , Hu Wentao , Dong Feifei
Published: February 2013

Higher order cumulants (HOC) is a new kind of modern signal analysis of theory and technology. Spectrum entropy clustering (SEC) is a data mining method of statistics, extracting useful characteristics from a mass of nonlinear and non-stationary data. Following a discussion on the characteristics of HOC theory and SEC method in this paper, the study of signal processing techniques and the unique merits of nonlinear coupling characteristic analysis in processing random and non-stationary signals are introduced. Also, a new clustering analysis and diagnosis method is proposed for detecting multi-damage on gear by introducing the combination of HOC and SEC into the damage-detection and diagnosis of the gear system. The noise is restrained by HOC and by extracting coupling features and separating the characteristic signal at different speeds and frequency bands. Under such circumstances, the weak signal characteristics in the system are emphasized and the characteristic of multi-fault is extracted. Adopting a data-mining method of SEC conducts an analysis and diagnosis at various running states, such as the speed of 300 r/min, 900 r/min, 1200 r/min, and 1500 r/min of the following six signals: no-fault, short crack-fault in tooth root, long crack-fault in tooth root, short crack-fault in pitch circle, long crack-fault in pitch circle, and wear-fault on tooth. Research shows that this combined method of detection and diagnosis can also identify the degree of damage of some faults. On this basis, the virtual instrument of the gear system which detects damage and diagnoses faults is developed by combining with advantages of MATLAB and VC++, employing component object module technology, adopting mixed programming methods, and calling the program transformed from an *.m file under VC++. This software system possesses functions of collecting and introducing vibration signals of gear, analyzing and processing signals, extracting features, visualizing graphics, detecting and diagnosing faults, detecting and monitoring, etc. Finally, the results of testing and verifying show that the developed system can effectively be used to detect and diagnose faults in an actual operating gear transmission system.
Characteristics of thermal conductivity in classical water models
Authors: Sirk Timothy W. , Moore Stan , Brown Eugene F.
Published: February 2013

The thermal conductivities of common water models are compared using equilibrium (EMD) and non-equilibrium molecular dynamics (NEMD) simulation. A complete accounting for electrostatic contributions to the heat flux was found to resolve the previously reported differing results of NEMD and EMD Green-Kubo measurements for the extended simple point-charge (SPC/E) model. Accordingly, we demonstrate the influence of long-range electrostatics on the thermal conductivity with a simple coulomb cutoff, Ewald summation, and by an extended particle-particle particle-mesh method. For each water model, the thermal conductivity is computed and decomposed in terms of frequency-dependent thermodynamic and topological contributions. The rigid, three-site SPC, SPC/E, and transferable intermolecular potential (TIP3P-Ew) water models are shown to have similar thermal conductivity values at standard conditions, whereas models that include bond stretching and angle bending have higher thermal conductivities.
Temperature and length scale dependence of solvophobic solvation in a single-site water-like liquid
Authors: Dowdle John R. , Buldyrev Sergey V. , Stanley H. Eugene , Debenedetti Pablo G. , Rossky Peter J.
Published: February 2013

The temperature and length scale dependence of solvation properties of spherical hard solvophobic solutes is investigated in the Jagla liquid, a simple liquid that consists of particles interacting via a spherically symmetric potential combining a hard core repulsion and a longer ranged soft core interaction, yet exhibits water-like anomalies. The results are compared with equivalent calculations for a model of a typical atomic liquid, the Lennard-Jones potential, and with predictions for hydrophobic solvation in water using the cavity equation of state and the extended simple point charge model. We find that the Jagla liquid captures the qualitative thermodynamic behavior of hydrophobic hydration as a function of temperature for both small and large length scale solutes. In particular, for both the Jagla liquid and water, we observe temperature-dependent enthalpy and entropy of solvation for all solute sizes as well as a negative solvation entropy for sufficiently small solutes at low temperature. This feature of water-like solvation is distinct from the strictly positive and temperature independent enthalpy and entropy of cavity solvation observed in the Lennard-Jones fluid. The results suggest that, compared to a simple liquid, it is the presence of a second thermally accessible repulsive energy scale, acting to increasingly favor larger separations for decreasing temperature, that is the essential characteristic of a liquid that favors low-density, open structures, and models hydrophobic hydration, and that it is the presence of this second energy scale that leads to the similarity in the behavior of water and the Jagla liquid. In addition, the Jagla liquid dewets surfaces of large radii of curvature less readily than the Lennard-Jones liquid, reflecting a greater flexibility or elasticity in the Jagla liquid structure than that of a typical liquid, a behavior also similar to that of water's hydrogen bonding network. The implications of the temperature and length scale dependence of solvation free energies in water-like liquids are explored with a simple model for the aggregation of solvophobic solutes. We show how aggregate stability depends upon the size of the aggregate and the size of its constituent solutes, and we relate this dependence to cold-induced destabilization phenomena such as the cold-induced denaturation of proteins.
Short range order in bimetallic nanoalloys: An extended X-ray absorption fine structure study
Authors: Frenkel Anatoly I. , Wang Qi , Sanchez Sergio I. , Small Matthew W. , Nuzzo Ralph G.
Published: February 2013

Partial coordination numbers measured by extended X-ray absorption fine structure (EXAFS) spectroscopy have been used for decades to resolve between different compositional motifs in bulk and nanoscale bimetallic alloys. Due to the ensemble-averaging nature of EXAFS, the values of the coordination numbers in nanoparticles cannot be simply interpreted in terms of the degree of alloying or segregation if the compositional distribution is broad. We demonstrate that a Cowley short range order parameter is an objective measure of either the segregation tendency (e.g., a core-shell type) or the degree of randomness (in homogeneous nanoalloys). This criterion can be used even in the case when the clusters are random but have broad compositional distributions. All cases are illustrated using the analyses of EXAFS data obtained in three different nanoscale bimetallic systems: Pt(core)-Pd(shell), Pd(core)-Pt(shell), and Pt-Pd random alloy.
Plasma nitriding process by direct current glow discharge at low temperature increasing the thermal diffusivity of AISI 304 stainless steel
Authors: Prandel L. V. , Somer A. , Assmann A. , Camelotti F. , Costa G. , Bonardi C. , Jurelo A. R. , Rodrigues J. B. , Cruz G. K.
Published: February 2013

This work reports for the first time on the use of the open photoacoustic cell technique operating at very low frequencies and at room temperature to experimentally determine the thermal diffusivity parameter of commercial AISI304 stainless steel and AISI304 stainless steel nitrided samples. Complementary measurements of X-ray diffraction and scanning electron microscopy were also performed. The results show that in standard AISI 304 stainless steel samples the thermal diffusivity is (4.0 ± 0.3) × 10−6 m2/s. After the nitriding process, the thermal diffusivity increases to the value (7.1 ± 0.5) × 10−6 m2/s. The results are being associated to the diffusion process of nitrogen into the surface of the sample. Carrying out subsequent thermal treatment at 500 °C, the thermal diffusivity increases up to (12.0 ± 2) × 10−6 m2/s. Now the observed growing in the thermal diffusivity must be related to the change in the phases contained in the nitrided layer.
Intraband optical transition in InGaAs/GaAs pyramidal quantum dots
Authors: Chaganti Venkata R , Apalkov Vadym
Published: February 2013

We present the results of our numerical analysis of intraband optical transitions within the valence band of InxGa1−xAs/GaAs pyramidal quantum dots. We study the possibility of tuning of the corresponding absorption spectra by varying the size and composition of the dots. The composition of the dot is varied by changing the value of ‘x’ between x = 0.1 and x = 1.0. The size of the quantum dot base is varied from 5 nm to 21 nm. The absorption spectra are calculated within the eight-band k.p model, which includes the effects of strain. The absorption spectra of the quantum dots are more sensitive to the in-plane, i.e., perpendicular to the growth direction and polarization of the incident light.
A comparative study of two molecular mechanics models based on harmonic potentials
Authors: Zhao Junhua , Wang Lifeng , Jiang Jin-Wu , Wang Zhengzhong , Guo Wanlin , Rabczuk Timon
Published: February 2013

We show that the two molecular mechanics models, the stick-spiral and the beam models, predict considerably different mechanical properties of materials based on energy equivalence. The difference between the two models is independent of the materials since all parameters of the beam model are obtained from the harmonic potentials. We demonstrate this difference for finite width graphene nanoribbons and a single polyethylene chain comparing results of the molecular dynamics (MD) simulations with harmonic potentials and the finite element method with the beam model. We also find that the difference strongly depends on the loading modes, chirality and width of the graphene nanoribbons, and it increases with decreasing width of the nanoribbons under pure bending condition. The maximum difference of the predicted mechanical properties using the two models can exceed 300% in different loading modes. Comparing the two models with the MD results of AIREBO potential, we find that the stick-spiral model overestimates and the beam model underestimates the mechanical properties in narrow armchair graphene nanoribbons under pure bending condition.
Active control of dielectrophoretic force at nanowire electrode for ultrahigh single nanoparticle manipulation yield
Authors: Kim Jinsik , Lee Sangyoup , Francis Suh Jun-Kyo , Ho Park Jung , Shin Hyun-Joon
Published: February 2013

We introduce ultrahigh-yield single nanoparticle control based on active control of the dielectrophoretic (DEP) force (ACDF). Attachment and detachment are accomplished reversibly using a combination of negative and positive DEP forces. A silicon-oxide (SiO2)-surrounded gold nanowire electrode was designed for ACDF. Nanoparticle motions were analyzed to confirm inducement of the negative DEP force, which is the most important for realizing ACDF. Polystyrene nanobeads and quantum dots were used. Ultrahigh-yield single nanoparticle manipulation was achieved at every designed position using ACDF.
Role of covalent hybridization in the martensitic structure and magnetic properties of shape-memory alloys: The case of Ni50Mn5+xGa35-xCu10
Authors: Li G. J. , Liu E. K. , Zhang H. G. , Zhang Y. J. , Xu G. Z. , Luo H. Z. , Zhang H. W. , Wang W. H. , Wu G. H.
Published: February 2013

The influence of covalent hybridization on the martensitic structure and magnetic properties of Ni50Mn5+xGa35−xCu10 shape-memory alloys has been investigated. It is found that the lattice distortion (c − a)/a of L10 martensite linearly increases upon substitution of Mn for Ga, showing a change of slope at Ga = 25 at. %, which is ascribed to a weakened covalent hybridization between main-group and transition-metal atoms. Moreover, due to the competition between the covalent hybridization and the magnetic ordering of the substituted Mn atoms, the magnetic moment per formula unit and the Curie temperature show maxima at Ga = 25 at. % as well. This behavior is closely associated with the corresponding changes of the strength of the covalent hybridization. The results, therefore, suggest that a careful control of the concentration of main-group atoms in Heusler alloys may serve as a tuning parameter for finding multifunctional materials.
Note: A 3-stage stacked Blumlein using ceramic for energy storage
Authors: Wang Songsong , Shu Ting , Yang Hanwu
Published: February 2013

We have developed a novel stacked Blumlein with high compactness by using ceramic for energy storage. The total volume of this stacked Blumlein is only 320 × 100 × 185 mm3. By triggering 3 spark gaps simultaneously, the developed stacked Blumlein is capable of producing a rectangular pulse with a voltage multiplication. A 32 ns quasi-rectangular pulse of 11.4 kV is measured across a 10 Ω dummy load when the 3-stage stacked Blumlein is DC charged up to 4 kV. The voltage multiplication is about 2.9, and the energy efficiency is about 96%. Simulation results indicate that vacuum or transformer oil is appropriate to be the insulation medium for the stacked Blumlein.
Note: A new design for a low-temperature high-intensity helium beam source
Authors: Lechner B. A. J. , Hedgeland H. , Allison W. , Ellis J. , Jardine A. P.
Published: February 2013

A high-intensity supersonic beam source is a key component of any atom scattering instrument, affecting the sensitivity and energy resolution of the experiment. We present a new design for a source which can operate at temperatures as low as 11.8 K, corresponding to a beam energy of 2.5 meV. The new source improves the resolution of the Cambridge helium spin-echo spectrometer by a factor of 5.5, thus extending the accessible timescales into the nanosecond range. We describe the design of the new source and discuss experiments characterizing its performance. Spin-echo measurements of benzene/Cu(100) illustrate its merit in the study of a typical slow-moving molecular adsorbate species.
Au impact on GaAs epitaxial growth on GaAs (111)B substrates in molecular beam epitaxy
Authors: Liao Zhi-Ming , Chen Zhi-Gang , Lu Zhen-Yu , Xu Hong-Yi , Guo Ya-Nan , Sun Wen , Zhang Zhi , Yang Lei , Chen Ping-Ping , Lu Wei , Zou Jin
Published: February 2013

GaAs growth behaviour under the presence of Au nanoparticles on GaAs {111}B substrate is investigated using electron microscopy. It has been found that, during annealing, enhanced Ga surface diffusion towards Au nanoparticles leads to the GaAs epitaxial growth into {113}B faceted triangular pyramids under Au nanoparticles, governed by the thermodynamic growth, while during conventional GaAs growth, growth kinetics dominates, resulting in the flatted triangular pyramids at high temperature and the epitaxial nanowires growth at relatively low temperature. This study provides an insight of Au nanoparticle impact on GaAs growth, which is critical for understanding the formation mechanisms of semiconductor nanowires.
An optical technique for fast and ultrasensitive detection of ammonia using magnetic nanofluids
Authors: Mahendran V. , Philip John
Published: February 2013

We report a simple, in-expensive, portable, and ultrasensitive optical sensor for detection of ammonia in parts per million levels using magnetic nanofluids. The sensor produces visually perceptible color changes, in the presence of ammonia, due to the changes in the lattice periodicity of 1-dimensional array of droplets. The penetration of ammonia into the diffused electric double layer around the emulsion droplet causes significant blue shift in the diffracted Bragg peak. The mechanism of the blue shift is probed by measuring the subtle changes in the intermolecular forces in the presence of ammonia. The present approach is useful for online monitoring of ammonia.
Joule's law for organic transistors exploration: Case of contact resistance
Authors: Xu Yong , Liu Chuan , Li Yun , Minari Takeo , Darmawan Peter , Balestra Francis , Ghibaudo Gerard , Tsukagoshi Kazuhito
Published: February 2013

Joule's law opens a straightforward way to explore the operating mechanism of organic field-effect transistors, from the angle of inner transported heating. The microscopic dissipated power is calculated from the local conductivity and electric field, which solves the widespread difficulties in building a macroscopic model to determine the contact resistance. The result quantitatively discloses the correlation between the contact resistance and the charge transport properties covering energetic disorder, band-like and hopping transport as well as carrier mobility anisotropy. It turns out that in a staggered configuration with ideal Ohmic contact, the contact resistance is highly affected by the charge transport.
Stability of MnB2 with AlB2-type structure revealed by first-principles calculations and experiments
Authors: Gou Huiyang , Steinle-Neumann Gerd , Bykova Elena , Nakajima Yoichi , Miyajima Nobuyoshi , Li Yuan , Ovsyannikov Sergey V. , Dubrovinsky Leonid S. , Dubrovinskaia Natalia
Published: February 2013

MnB2 with the ReB2-type structure has been theoretically predicted to be a superhard material which could be synthesized at ambient pressure. However, this phase has not been observed experimentally to date. In the present work, we show that even applying moderate pressure does not facilitate the formation of ReB2-structured MnB2. Our high-pressure high-temperature experiments resulted in the synthesis of single crystals of MnB2 with the previously known AlB2-type structure. This is at odds with results from density functional theory-based calculations using the generalized gradient approximation (GGA). The discrepancy with the computational prediction was reconciled by including on-site repulsion (GGA + U), which found the anti-ferromagnetically ordered AlB2-type structure energetically favored over the ReB2-structure for MnB2.
Devices with electrically tunable topological insulating phases
Authors: Michetti Paolo , Trauzettel Björn
Published: February 2013

Solid-state topological insulating phases, characterized by spin-momentum locked edge modes, provide a powerful route for spin and charge manipulation in electronic devices. We propose to control charge and spin transport in the helical edge modes by electrically switching the topological insulating phase in a HgTe/CdTe double quantum well device. We introduce the concept of a topological field-effect-transistor and analyze possible applications to a spin battery, which also realize a set up for an all-electrical investigation of the spin-polarization dynamics in metallic islands.
A Family of Three-Dimensional Molecular Framework Materials Containing the Three-Connecting Ligands 2,4,6-Tris(n'-pyridyl)-1,3,5-triazine: 3-tpt and 4-tpt
Authors: Neville Suzanne M. , Halder Gregory J. , Murray Keith S. , Moubaraki Boujemaa , Kepert Cameron J.
Published: February 2013

Three-dimensional (3D) framework materials containing the ligands 2,4,6-tris(4′-pyridyl)-1,3,5-triazine (4-tpt) and 2,4,6-tris(3′-pyridyl)-1,3,5-triazine (3-tpt) have been prepared and their structure and magnetic properties investigated. The [MII(NCS)2(py)4] (MII = Fe, Co, py = 3-tpt, and 4-tpt) coordination environments in these materials have been targeted in an effort to prepare high-dimensional coordination polymers which contain spin crossover (SCO) centres. Using FeII, two isotopological cubic 3D materials [Fe(NCS)2(4-tpt)4/3]·n(BzOH,ac) (1a(Bz,ac)) and [Fe(NCS)2(3-tpt)4/3]·n(BzOH,ac) (1b(Bz,ac)) were formed. However, with CoII a different 3D framework topology results, [Co(NCS)2(3-tpt)4/3]·(BzOH,ac) (2(Bz,ac)). Further synthetic variation leads to the isostructural 3D materials trans-[MII(NCS)2(4-tpt)4/3]cis-[MII(NCS)2(4-tpt)2]·n(tce, EtOH) (Fe: 3a(Tce,Et) and Co: 3b(Tce,Et)) which form 3D networks outside Wellsian classification – and for which uniquely both two- and three-connecting modes of 4-tpt are present in the one complex. Despite having the metal coordination environments for which SCO has previously been observed, magnetic susceptibilities of this family of materials reveal a high spin nature.
Rehabilitation of an incised ephemeral stream in central New South Wales, Australia: identification of incision causes, rehabilitation techniques and channel response
Authors: Streeton N. A. , Greene R. S. B. , Marchiori K. , Tongway D. J. , Carnegie M. D.
Published: February 2013

The degradation of semiarid agricultural rangelands in Australia can be traced back to the 19th century when Europeans expanded into these areas. That environmental degradation remains today and continues to harm agricultural productivity. The rehabilitation of a strongly incised ephemeral stream, ‘Spring Creek’, in central New South Wales, as an example of what can be achieved readily by landowners, is described. The causes of environmental degradation and the main environmental factors leading to the stream erosion were identified, rehabilitation began and the behaviour of the regime for 5 years within Spring Creek and the adjacent floodplain was monitored. It was found that intrinsically unstable sub-soils and sparse ground cover due to persistent grazing by domestic livestock were the major factors leading to incision. Several physical and chemical properties were found to be the primary causes of the soil’s instability.
Rehabilitation focussed on stabilising the soils alongside the stream, promoting sedimentation and re-vegetation of the stream bed, with a longer-term objective of increasing the transfer of water, sediments and nutrients between the stream and its adjacent floodplain. The measures, implemented by local landowners, included the provision of in-stream porous rock weirs and the lowering of the grazing pressure on the stream bed and adjacent floodplain. Monitoring in 2007, 2009 and 2011 indicated that sedimentation was substantially faster above weirs than where there were no weirs. The rehabilitative measures resulted in the retention of fine sediment (<0.2 mm) along the stream bed behind weirs.
The problem of optimum allocation in multivariate stratified sampling
Authors: Fatima Ummatul , Ghufran Shazia , Ahsan M. J.
Published: February 2013

Generally, sample surveys are multivariate in nature where multiple response are obtained on every unit selected in a sample, that is, more than one characteristics are defined on each and every unit of the population. While dealing with a multivariate stratified population, to workout an allocation that is optimum for all characteristics is almost impossible unless the characteristics are highly correlated. Some compromise must be
allowed to obtain an allocation that is optimum, in some sense, for all the characteristics. Since such allocations are based on some compromise criteria they are known as compromise allocations. This paper deals with the problem of obtaining an optimum allocation in multivariate stratified sampling design.
Determination of n-alkane profile through developmental state of sunflower leaves
Authors: Roy Nayan , Laskar Subrata , Barik Anandamay
Published: February 2013

The n-hexane extracts of young, mature and senescent sunflower leaves containing a thin layer of epicuticular waxes was analysed by TLC and GC using standard hydrocarbons. The Scanning Electron Microscopy study indicated changes in the deposition of epicuticular wax throughout the developmental stage of the sunflower leaves. The young, mature and senescent leaves contained nine, nine and five long-chain nalkanes accounting for 86.22%, 99.76% and 92.07% of the hydrocarbons, respectively. The predominant nalkane was n-C29 for young and mature leaves, and n-C23 for senescent leaves representing 35.85%, 45.37% and 68.54% of the hydrocarbons, respectively; whilst n-C24, n-C32 and n-C19 were present in least amounts in young, mature and senescent leaves indicating 0.59%, 0.83% and 0.53% of the hydrocarbons, respectively.
Automated reconstruction of ancient languages using probabilistic models of sound change
Authors: Bouchard-Côté Alexandre , Hall David , Griffiths Thomas L. , Klein Dan
Published: February 2013

One of the oldest problems in linguistics is reconstructing the words that appeared in the protolanguages from which modern languages evolved. Identifying the forms of these ancient languages makes it possible to evaluate proposals about the nature of language change and to draw inferences about human history. Protolanguages are typically reconstructed using a painstaking manual process known as the comparative method. We present a family of probabilistic models of sound change as well as algorithms for performing inference in these models. The resulting system automatically and accurately reconstructs protolanguages from modern languages. We apply this system to 637 Austronesian languages, providing an accurate, large-scale automatic reconstruction of a set of protolanguages. Over 85% of the system’s reconstructions are within one character of the manual reconstruction provided by a linguist specializing in Austronesian languages. Being able to automatically reconstruct large numbers of languages provides a useful way to quantitatively explore hypotheses about the factors determining which sounds in a language are likely to change over time. We demonstrate this by showing that the reconstructed Austronesian protolanguages provide compelling support for a hypothesis about the relationship between the function of a sound and its probability of changing that was first proposed in 1955.
Quantitative algebraic topology and Lipschitz homotopy
Authors: Ferry Steve , Weinberger Shmuel
Published: February 2013

We consider when it is possible to bound the Lipschitz constant a priori in a homotopy between Lipschitz maps. If one wants uniform bounds, this is essentially a finiteness condition on homotopy. This contrasts strongly with the question of whether one can homotop the maps through Lipschitz maps. We also give an application to cobordism and discuss analogous isotopy questions.
Strontium isotopes document greater human mobility at the start of the Balkan Neolithic
Authors: Borić Dušan , Price T. Douglas
Published: February 2013

Questions about how farming and the Neolithic way of life spread across Europe have been hotly debated topics in archaeology for decades. For a very long time, two models have dominated the discussion: migrations of farming groups from southwestern Asia versus diffusion of domesticates and new ideas through the existing networks of local forager populations. New strontium isotope data from the Danube Gorges in the north-central Balkans, an area characterized by a rich burial record spanning the Mesolithic–Neolithic transition, show a significant increase in nonlocal individuals from ∼6200 calibrated B.C., with several waves of migrants into this region. These results are further enhanced by dietary evidence based on carbon and nitrogen isotopes and an increasingly high chronological resolution obtained on a large sample of directly dated individuals. This dataset provides robust evidence for a brief period of coexistence between indigenous groups and early farmers before farming communities absorbed the foragers completely in the first half of the sixth millennium B.C.
Neto2 is a KCC2 interacting protein required for neuronal Cl
−
regulation in hippocampal neurons
Authors: Ivakine Evgueni A. , Acton Brooke A. , Mahadevan Vivek , Ormond Jake , Tang Man , Pressey Jessica C. , Huang Michelle Y. , Ng David , Delpire Eric , Salter Michael W. , Woodin Melanie A. , McInnes Roderick R.
Published: February 2013

KCC2 is a neuron-specific K
+
–Cl
−
cotransporter that is essential for Cl
−
homeostasis and fast inhibitory synaptic transmission in the mature CNS. Despite the critical role of KCC2 in neurons, the mechanisms regulating its function are not understood. Here, we show that KCC2 is critically regulated by the single-pass transmembrane protein neuropilin and tolloid like-2 (Neto2). Neto2 is required to maintain the normal abundance of KCC2 and specifically associates with the active oligomeric form of the transporter. Loss of the Neto2:KCC2 interaction reduced KCC2-mediated Cl
−
extrusion, resulting in decreased synaptic inhibition in hippocampal neurons.
Stress increases aversive prediction error signal in the ventral striatum
Authors: Robinson Oliver J. , Overstreet Cassie , Charney Danielle R. , Vytal Katherine , Grillon Christian
Published: February 2013

From job interviews to the heat of battle, it is evident that people think and learn differently when stressed. In fact, learning under stress may have long-term consequences; stress facilitates aversive conditioning and associations learned during extreme stress may result in debilitating emotional responses in posttraumatic stress disorder. The mechanisms underpinning such stress-related associations, however, are unknown. Computational neuroscience has successfully characterized several mechanisms critical for associative learning under normative conditions. One such mechanism, the detection of a mismatch between expected and observed outcomes within the ventral striatum (i.e., “prediction errors”), is thought to be a critical precursor to the formation of new stimulus–outcome associations. An untested possibility, therefore, is that stress may affect learning via modulation of this mechanism. Here we combine a translational model of stress with a cognitive neuroimaging paradigm to demonstrate that stress significantly increases ventral striatum aversive (but not appetitive) prediction error signal. This provides a unique account of the propensity to form threat-related associations under stress with direct implications for our understanding of both normal stress and stress-related disorders.
Alternative erythropoietin-mediated signaling prevents secondary microvascular thrombosis and inflammation within cutaneous burns
Authors: Bohr Stefan , Patel Suraj J. , Shen Keyue , Vitalo Antonia G. , Brines Michael , Cerami Anthony , Berthiaume Francois , Yarmush Martin L.
Published: February 2013

Alternate erythropoietin (EPO)–mediated signaling via the heteromeric receptor composed of the EPO receptor and the β-common receptor (CD131) exerts the tissue-protective actions of EPO in various types of injuries. Herein we investigated the effects of the EPO derivative helix beta surface peptide (synonym: ARA290), which specifically triggers alternate EPO-mediated signaling, but does not bind the erythropoietic EPO receptor homodimer, on the progression of secondary tissue damage following cutaneous burns. For this purpose, a deep partial thickness cutaneous burn injury was applied on the back of mice, followed by systemic administration of vehicle or ARA290 at 1, 12, and 24 h postburn. With vehicle-only treatment, wounds exhibited secondary microvascular thrombosis within 24 h postburn, and subsequent necrosis of the surrounding tissue, thus converting to a full-thickness injury within 48 h. On the other hand, when ARA290 was systemically administered, patency of the microvasculature was maintained. Furthermore, ARA290 mitigated the innate inflammatory response, most notably tumor necrosis factor-alpha–mediated signaling. These findings correlated with long-term recovery of initially injured yet viable tissue components. In conclusion, ARA290 may be a promising therapeutic approach to prevent the conversion of partial- to full-thickness burn injuries. In a clinical setting, the decrease in burn depth and area would likely reduce the necessity for extensive surgical debridement as well as secondary wound closure by means of skin grafting. This use of ARA290 is consistent with its tissue-protective properties previously reported in other models of injury, such as myocardial infarction and hemorrhagic shock.
Generation of dispersion in nondispersive nonlinear waves in thermal equilibrium
Authors: Lee Wonjung , Kovačič Gregor , Cai David
Published: February 2013

In this work, we examine the important theoretical question of whether dispersion relations can arise from purely nonlinear interactions among waves that possess no linear dispersive characteristics. Using two prototypical examples of nondispersive waves, we demonstrate how nonlinear interactions can indeed give rise to effective dispersive-wave–like characteristics in thermal equilibrium. Physically, these example systems correspond to the strong nonlinear coupling limit in the theory of wave turbulence. We derive the form of the corresponding dispersion relation, which describes the effective dispersive structures, using the generalized Langevin equations obtained in the Zwanzig–Mori projection framework. We confirm the validity of this effective dispersion relation in our numerical study using the wavenumber–frequency spectral analysis. Our work may provide insight into an important connection between highly nonlinear turbulent wave systems, possibly with no discernible dispersive properties, and the dispersive nature of the corresponding renormalized waves.
Fossil evidence for a hyperdiverse sclerophyll flora under a non–Mediterranean-type climate
Authors: Sniderman J. M. Kale , Jordan Gregory J. , Cowling Richard M.
Published: February 2013

The spectacular diversity of sclerophyll plants in the Cape Floristic Region in South Africa and Australia’s Southwest Floristic Region has been attributed to either explosive radiation on infertile soils under fire-prone, summer-dry climates or sustained accretion of species under inferred stable climate regimes. However, the very poor fossil record of these regions has made these ideas difficult to test. Here, we reconstruct ecological-scale plant species richness from an exceptionally well-preserved fossil flora. We show that a hyperdiverse sclerophyll flora existed under high-rainfall, summer-wet climates in the Early Pleistocene in southeastern Australia. The sclerophyll flora of this region must, therefore, have suffered subsequent extinctions to result in its current relatively low diversity. This regional loss of sclerophyll diversity occurred at the same time as a loss of rainforest diversity and cannot be explained by ecological substitution of species of one ecological type by another type. We show that sclerophyll hyperdiversity has developed in distinctly non-Mediterranean climates, and this diversity is, therefore, more likely a response to long-term climate stability. Climate stability may have both reduced the intensity of extinctions associated with the Pleistocene climate cycles and promoted the accumulation of species richness by encouraging genetic divergence between populations and discouraging plant dispersal.