bluuebunny/crossref_metadata_2025 huggingface dataset:
Tidal Stability of Giant Molecular Clouds in the Large Magellanic Cloud
Authors: Thilliez E. , Maddison S. T. , Hughes A. , Wong T.
Published: February 2014

Star formation does not occur until the onset of gravitational collapse inside giant molecular clouds. However, the conditions that initiate cloud collapse and regulate the star formation process remain poorly understood. Local processes such as turbulence and magnetic fields can act to promote or prevent collapse. On larger scales, the galactic potential can also influence cloud stability and is traditionally assessed by the tidal and shear effects.

In this paper, we examine the stability of giant molecular clouds (GMCs) in the Large Magellanic Cloud (LMC) against shear and the galactic tide using CO data from the Magellanic Mopra Assessment (MAGMA) and rotation curve data from the literature. We calculate the tidal acceleration experienced by individual GMCs and determine the minimum cloud mass required for tidal stability. We also calculate the shear parameter, which is a measure of a cloud's susceptibility to disruption via shearing forces in the galactic disk. We examine whether there are correlations between the properties and star forming activity of GMCs and their stability against shear and tidal disruption.

We find that the GMCs are in approximate tidal balance in the LMC, and that shear is unlikely to affect their further evolution. GMCs with masses close to the minimal stable mass against tidal disruption are not unusual in terms of their mass, location, or CO brightness, but we note that GMCs with large velocity dispersion tend to be more sensitive to tidal instability. We also note that GMCs with smaller radii, which represent the majority of our sample, tend to more strongly resist tidal and shear disruption. Our results demonstrate that star formation in the LMC is not inhibited by to tidal or shear instability.
Leishmania mexicanalipophosphoglycan activates ERK and p38 MAP kinase and induces production of proinflammatory cytokines in human macrophages through TLR2 and TLR4
Authors: ROJAS-BERNABÉ A. , GARCIA-HERNÁNDEZ O. , MALDONADO-BERNAL C. , DELEGADO-DOMINGUEZ J. , ORTEGA E. , GUTIÉRREZ-KOBEH L. , BECKER I. , AGUIRRE-GARCIA M.
Published: February 2014

Protozoan parasites of genusLeishmaniaare the causative agents of leishmaniasis.Leishmaniapromastigotes primarily infect macrophages in the host, where they transform into amastigotes and multiply. Lipophosphoglycan (LPG), the most abundant surface molecule of the parasite, is a virulence determinant that regulates the host immune response. Promastigotes are able to modulate this effect through LPG, creating a favourable environment for parasite survival, although the mechanisms underlying this modulation remain unknown. We analysed the participation of TLR2 and TLR4 in the production of cytokines and explored the possible phosphorylation of ERK and/or p38 MAP kinase signalling cascades in human macrophages stimulated withLeishmania mexicanaLPG. The results show that LPG induced the production of TNF-α, IL-1β, IL-12p40, IL-12p70 and IL-10 and led to phosphorylation of ERK and p38 MAP kinase. Specific inhibitors of ERK or p38 MAP kinases and mAbs against TLR2 and TLR4 reduced cytokine production and phosphorylation of both kinases. Our results suggest thatL. mexicanaLPG binds TLR2 and TLR4 receptors in human macrophages, leading to ERK and MAP kinase phosphorylation and production of pro-inflammatory cytokines.
Early predictive biomarkers for postpartum depression point to a role for estrogen receptor signaling
Authors: Mehta D. , Newport D. J. , Frishman G. , Kraus L. , Rex-Haffner M. , Ritchie J. C. , Lori A. , Knight B. T. , Stagnaro E. , Ruepp A. , Stowe Z. N. , Binder E. B.
Published: February 2014

Background

Postpartum depression (PPD) affects approximately 13% of women and has a negative impact on mother and infant, hence reliable biological tests for early detection of PPD are essential. We aimed to identify robust predictive biomarkers for PPD using peripheral blood gene expression profiles in a hypothesis-free genome-wide study in a high-risk, longitudinal cohort.

Method

We performed a genome-wide association study in a longitudinal discovery cohort comprising 62 women with psychopathology. Gene expression and hormones were measured in the first and third pregnancy trimesters and early postpartum (201 samples). The replication cohort comprised 24 women with third pregnancy trimester gene expression measures. Gene expression was measured on Illumina-Human HT12 v4 microarrays. Plasma estradiol and estriol were measured. Statistical analysis was performed in R.

Results

We identified 116 transcripts differentially expressed between the PPD and euthymic women during the third trimester that allowed prediction of PPD with an accuracy of 88% in both discovery and replication cohorts. Within these transcripts, significant enrichment of transcripts implicated that estrogen signaling was observed and such enrichment was also evident when analysing published gene expression data predicting PPD from a non-risk cohort. While plasma estrogen levels were not different across groups, women with PPD displayed an increased sensitivity to estrogen signaling, confirming the previously proposed hypothesis of increased sex-steroid sensitivity as a susceptibility factor for PPD.

Conclusions

These results suggest that PPD can be robustly predicted in currently euthymic women as early as the third trimester and these findings have implications for predictive testing of high-risk women and prevention and treatment for PPD.
MOOCs for nothing and the VLC for free
Authors: Sheldon Neil
Published: February 2014

Massive Open Online Courses (MOOCs) are big news in higher education at the moment, with hundreds of the world's leading universities offering free access to lectures and other resources. Many MOOC providers operate through platforms such as edX, a not-for-profit consortium formed by MIT, Harvard and Berkeley, or commercially oriented platforms such as Udacity and Coursera. The last two provide the courses free, but aim to make money by charging for certification, or by making data on MOOC graduates available to recruiters. And the numbers involved are huge: MOOCs can attract tens of thousands, even hundreds of thousands, of enrolments.
Generation and characterization of regulatory dendritic cells derived from murine induced pluripotent stem cells
Authors: Zhang Qi , Fujino Masayuki , Iwasaki Shizue , Hirano Hiroshi , Cai Songjie , Kitajima Yuya , Xu Jinhua , Li Xiao-Kang
Published: February 2014

Regulatory dendritic cells (DCregs) represent a potential therapeutic tool for assessing a variety of immune overreaction conditions; however, current approaches for generating DCregs for therapeutic purposes are limited. We attempted to generate and characterize DCregs from murine induced pluripotent stem (iPS) cells. The iPS cells co-cultured with OP9 cells displayed mesodermally differentiated flat colonies. GM-CSF drove most of the colonies exhibiting a differentiated morphology. Thereafter, cells became morphologically heterologous under the effects of TGF-β and IL-10. Most of the floating cells developed an irregular shape with areas of protrusion. The generated iPS-DCregs demonstrated high CD11b/c and low CD40, CD80, CD86 and MHC-II expressions with a high antigen uptake ability and poor T-cell stimulatory function. Importantly, iPS-DCregs showed immune responsiveness regulation effects both in vitro and in vivo and the ability to generate regulatory T-cells in vitro. Our result illustrates a feasible approach for generating functional DCregs from murine iPS cells.
Resolving the role of femtosecond heated electrons in ultrafast spin dynamics
Authors: Mendil J. , Nieves P. , Chubykalo-Fesenko O. , Walowski J. , Santos T. , Pisana S. , Münzenberg M.
Published: February 2014

Magnetization manipulation is essential for basic research and applications. A fundamental question is, how fast can the magnetization be reversed in nanoscale magnetic storage media. When subject to an ultrafast laser pulse, the speed of the magnetization dynamics depends on the nature of the energy transfer pathway. The order of the spin system can be effectively influenced through spin-flip processes mediated by hot electrons. It has been predicted that as electrons drive spins into the regime close to almost total demagnetization, characterized by a loss of ferromagnetic correlations near criticality, a second slower demagnetization process takes place after the initial fast drop of magnetization. By studying FePt, we unravel the fundamental role of the electronic structure. As the ferromagnet Fe becomes more noble in the FePt compound, the electronic structure is changed and the density of states around the Fermi level is reduced, thereby driving the spin correlations into the limit of critical fluctuations. We demonstrate the impact of the electrons and the ferromagnetic interactions, which allows a general insight into the mechanisms of spin dynamics when the ferromagnetic state is highly excited and identifies possible recording speed limits in heat-assisted magnetization reversal.
Fine-tuned Bee-Flower Coevolutionary State Hidden within Multiple Pollination Interactions
Authors: Shimizu Akira , Dohzono Ikumi , Nakaji Masayoshi , Roff Derek A. , Miller III Donald G. , Osato Sara , Yajima Takuya , Niitsu Shûhei , Utsugi Nozomu , Sugawara Takashi , Yoshimura Jin
Published: February 2014

Relationships between flowers and pollinators are generally considered cases of mutualism since both agents gain benefits. Fine-tuned adaptations are usually found in the form of strict one-to-one coevolution between species. Many insect pollinators are, however, considered generalists, visiting numerous kinds of flowers and many flower species (angiosperms) are also considered generalists, visited by many insect pollinators. We here describe a fine-tuned coevolutionary state of a flower-visiting bee that collects both nectar and pollen from an early spring flower visited by multiple pollinators. Detailed morphology of the bee proboscis is shown to be finely adjusted to the floral morphology and nectar production of the flower. Behavioral observations also confirm the precision of this mutualism. Our results suggest that a fine-tuned one-to-one coevolutionary state between a flower species and a pollinator species might be common, but frequently overlooked, in multiple flower-pollinator interactions.
A XANES study of chromophores: the case of black glass
Authors: Ceglia Andrea , Nuyts Gert , Cagno Simone , Meulebroeck Wendy , Baert Kitty , Cosyns Peter , Nys Karin , Thienpont Hugo , Janssens Koen , Terryn Herman
Published: February 2014

In the 1st–2nd century AD, glass was made black using strongly reducing conditions. Later, the black appearance was obtained adding an excess of colourant rather than controlling the furnace atmosphere.
Gold nanoparticle-based exonuclease III signal amplification for highly sensitive colorimetric detection of folate receptor
Authors: Yang Xinjian , Gao Zhiqiang
Published: February 2014

By combining terminal protection of small molecule (folate)-capped DNA probes, exonuclease III signal amplification and gold nanoparticles, we developed a simple and label-free colorimetric assay for highly sensitive detection of folate receptor.
Chromane helicity rule – scope and challenges based on an ECD study of various trolox derivatives
Authors: Górecki Marcin , Suszczyńska Agata , Woźnica Magdalena , Baj Aneta , Wolniak Michał , Cyrański Michał K. , Witkowski Stanisław , Frelek Jadwiga
Published: February 2014

The validity of the chromane helicity rule is examined using a set of natural (S)-trolox derivatives.
A novel PEG-based solid support enables the synthesis of >50 amino-acid peptide thioesters and the total synthesis of a functional SUMO-1 peptide conjugate
Authors: Boll Emmanuelle , Drobecq Hervé , Ollivier Nathalie , Raibaut Laurent , Desmet Rémi , Vicogne Jérome , Melnyk Oleg
Published: February 2014

Bis(2-sulfanylethyl)amino PEG resin gives access to large peptide thioester segments and to functional SUMO-1 conjugates.
A multiple ion-exchange membrane design for redox flow batteries
Authors: Gu Shuang , Gong Ke , Yan Emily Z. , Yan Yushan
Published: February 2014

A redox-flow-battery cell design with multiple ion-exchange membranes is provided to enable combinations of any redox pairs and supporting electrolytes.
Combining LC-MS/MS, PMF and N-terminal amino acid sequencing for multiplexed characterization of a bacterial surfactant glycoprotein biosynthesized by Acinetobacter radioresistens S13
Authors: Violetta Marta Riva , Mazzoli Roberto , Barello Cristina , Fattori Paolo , Giuffrida Maria G. , Pessione Enrica
Published: February 2014

The present study has highlighted the mechanisms of bacterial protein glycosylation. Experimental results underline that the consensus sequon can be different from the one found in Eukarya.
1D modelling of an alpha type Stirling engine
Authors: Martaj N. , Rochelle P.
Published: February 2014

In this paper, a 1-D model of an half alpha type “double-acting” Stirling engine (made up of two double-acting pistons, two hot heat-exchangers, two cold heat-exchangers and a common recuperator-regenerator for the two separate gas circuits, all that giving two cycles with 180° phasing) is presented. In this architecture, two cylinders, containing, each one, a double-acting piston, are combined in order to operate like two parallel Stirling systems in opposition of phase. This model, derived from Andersen’s model, is used to describe the compressible flows in the half-engine, under energy transfers. A finite-volume numerical method is applied for the equations of energy, mass and momentum assessment. This modelling was carried out using the Matlab/Simulink software. The results of this dynamic modelling relate to one half engine. We obtain the evolution of the physical parameters (density, pressure and temperature), and the (p, V) cycle. The influence of the various assumptions was studied. A parametric study was carried out in order to obtain the optimal values of the geometry of the engine and its ideal speed of operation.
Group contribution methodology based on the statistical associating fluid theory for heteronuclear molecules formed from Mie segments
Authors: Papaioannou Vasileios , Lafitte Thomas , Avendaño Carlos , Adjiman Claire S. , Jackson George , Müller Erich A. , Galindo Amparo
Published: February 2014

A generalization of the recent version of the statistical associating fluid theory for variable range Mie potentials [Lafitte et al., J. Chem. Phys. 139, 154504 (2013)] is formulated within the framework of a group contribution approach (SAFT-γ Mie). Molecules are represented as comprising distinct functional (chemical) groups based on a fused heteronuclear molecular model, where the interactions between segments are described with the Mie (generalized Lennard-Jonesium) potential of variable attractive and repulsive range. A key feature of the new theory is the accurate description of the monomeric group-group interactions by application of a high-temperature perturbation expansion up to third order. The capabilities of the SAFT-γ Mie approach are exemplified by studying the thermodynamic properties of two chemical families, the n-alkanes and the n-alkyl esters, by developing parameters for the methyl, methylene, and carboxylate functional groups (CH3, CH2, and COO). The approach is shown to describe accurately the fluid-phase behavior of the compounds considered with absolute average deviations of 1.20% and 0.42% for the vapor pressure and saturated liquid density, respectively, which represents a clear improvement over other existing SAFT-based group contribution approaches. The use of Mie potentials to describe the group-group interaction is shown to allow accurate simultaneous descriptions of the fluid-phase behavior and second-order thermodynamic derivative properties of the pure fluids based on a single set of group parameters. Furthermore, the application of the perturbation expansion to third order for the description of the reference monomeric fluid improves the predictions of the theory for the fluid-phase behavior of pure components in the near-critical region. The predictive capabilities of the approach stem from its formulation within a group-contribution formalism: predictions of the fluid-phase behavior and thermodynamic derivative properties of compounds not included in the development of group parameters are demonstrated. The performance of the theory is also critically assessed with predictions of the fluid-phase behavior (vapor-liquid and liquid-liquid equilibria) and excess thermodynamic properties of a variety of binary mixtures, including polymer solutions, where very good agreement with the experimental data is seen, without the need for adjustable mixture parameters.
VINETA II: A linear magnetic reconnection experiment
Authors: Bohlin H. , Von Stechow A. , Rahbarnia K. , Grulke O. , Klinger T.
Published: February 2014

A linear experiment dedicated to the study of driven magnetic reconnection is presented. The new device (VINETA II) is suitable for investigating both collisional and near collisionless reconnection. Reconnection is achieved by externally driving magnetic field lines towards an X-point, inducing a current in the background plasma which consequently modifies the magnetic field topology. Owing to the open field line configuration of the experiment, the current is limited by the axial sheath boundary conditions. A plasma gun is used as an additional electron source in order to counterbalance the charge separation effects and supply the required current. Two drive methods are used in the device. First, an oscillating current through two parallel conductors drive the reconnection. Second, a stationary X-point topology is formed by the parallel conductors, and the drive is achieved by an oscillating current through a third conductor. In the first setup, the magnetic field of the axial plasma current dominates the field topology near the X-point throughout most of the drive. The second setup allows for the amplitude of the plasma current as well as the motion of the flux to be set independently of the X-point topology of the parallel conductors.
Kohn-Sham orbitals and potentials from quantum Monte Carlo molecular densities
Authors: Varsano Daniele , Barborini Matteo , Guidoni Leonardo
Published: February 2014

In this work we show the possibility to extract Kohn-Sham orbitals, orbital energies, and exchange correlation potentials from accurate Quantum Monte Carlo (QMC) densities for atoms (He, Be, Ne) and molecules (H2, Be2, H2O, and C2H4). The Variational Monte Carlo (VMC) densities based on accurate Jastrow Antisymmetrised Geminal Power wave functions are calculated through different estimators. Using these reference densities, we extract the Kohn-Sham quantities with the method developed by Zhao, Morrison, and Parr (ZMP) [Phys. Rev. A 50, 2138 (1994)]. We compare these extracted quantities with those obtained form CISD densities and with other data reported in the literature, finding a good agreement between VMC and other high-level quantum chemistry methods. Our results demonstrate the applicability of the ZMP procedure to QMC molecular densities, that can be used for the testing and development of improved functionals and for the implementation of embedding schemes based on QMC and Density Functional Theory.
Kinetic theory of exciton–exciton annihilation
Authors: May Volkhard
Published: February 2014

Weakly excited states of dye aggregates and supramolecular complexes can be characterized by single or two exciton states. Stronger excitation results in the presence of multiple excited molecules, and complex processes of internal energy transfer dynamics take place. The direct consideration of all excited states is limited to systems with a few molecules only. Therefore, an approach is used based on transition operators among the molecular states of interest and resulting in a dynamic theory for excitation energy transfer in strongly excited molecular systems. As a first application of this theory a detailed description of exciton–exciton annihilation is given. The obtained novel nonlinear theory is related to the standard description. Possible further approximation schemes in the offered theoretical framework are discussed.
High-power, low-lateral divergence broad area quantum cascade lasers with a tilted front facet
Authors: Ahn Sangil , Schwarzer Clemens , Zederbauer Tobias , MacFarland Donald C. , Detz Hermann , Andrews Aaron M. , Schrenk Werner , Strasser Gottfried
Published: February 2014

We introduce a simple technique to improve the beam quality of broad area quantum cascade lasers. Moderately tilted front facets of the laser provide suppression of higher order lateral waveguide modes. A device with a width of 60 μm and a front facet angle of 17° shows a nearly diffraction limited beam profile. In addition, the peak output power and the slope efficiency of the device are increased since most of the light inside the cavity is emitted through the tilted front facet by an asymmetric light intensity distribution along the cavity.
Coaxial flow focusing in poly(dimethylsiloxane) microfluidic devices
Authors: Tran Tuan M. , Cater Sean , Abate Adam R.
Published: February 2014

We have developed a coaxial flow focusing geometry that can be fabricated using soft lithography in poly(dimethylsiloxane) (PDMS). Like coaxial flow focusing in glass capillary microfluidics, our geometry can form double emulsions in channels with uniform wettability and of a size much smaller than the channel dimensions. However, In contrast to glass capillary coaxial flow focusing, our geometry can be fabricated using lithographic techniques, allowing it to be integrated as the drop making unit in parallel drop maker arrays. Our geometry enables scalable formation of emulsions down 7 μm in diameter, in large channels that are robust against fouling and clogging.
Liquid supercoiling
Authors: Habibi Mehdi , Hosseini S. H. , Khatami M. H. , Ribe N. M.
Published: February 2014

Supercoiling is the large-scale secondary coiling or buckling of a structure that is already coiled at a smaller scale. Here, we show experimentally that a fluid-mechanical analog of supercoiling can occur when a thin “rope” of viscous fluid falls vertically from a great height onto a surface. For appropriate values of the viscosity ν, the flow rate Q, and the fall height H, a primary coiling instability of the rope forms a hollow coiled cylinder that then experiences a secondary buckling instability in the form of periodic folding accompanied by slow rotation of the folding plane. To delineate the conditions under which this supercoiling state appears, we carry out systematic laboratory experiments over wide ranges of Q and H using several fluids with different viscosities. We find that five different states of the rope are possible: supercoiling (SC), periodic collapse of the fluid cylinder formed by a primary coiling instability (PC), periodic folding (F), and steady coiling (C) of the rope itself, and axisymmetric stagnation flow (S). Up to three of these states can be realized for a given set of experimental conditions, and we determine detailed state diagrams showing which combinations are observed as a function of ν, Q, and H. The selection of the states is controlled by the dimensionless parameter gHQ2/ν4 (g is the gravitational acceleration), which is directly related to the ratio of the rope radius a to the coil radius R in steady primary coiling with the parameters ν, Q, and H.
The application of orthogonal photolithography to micro-scale organic field effect transistors and complementary inverters on flexible substrate
Authors: Jang Jingon , Song Younggul , Oh Hyuntaek , Yoo Daekyoung , Kim Dongku , Lee Hyungwoo , Hong Seunghun , Lee Jin-Kyun , Lee Takhee
Published: February 2014

Micro-scale pentacene organic field effect transistors (OFETs) were fabricated on a flexible poly(ethylene terephthalate) (PET) substrate. By applying a highly fluorinated developing solvents and its compatible photoresist materials, it has become possible to make the micro-scale patterning for organic devices using standard photolithography without damaging the underlying polymer layers. The flexible pentacene OFETs with 3 μm-sized channel length exhibited stable electrical characteristics under bent configurations and under a large number of repetitive bending cycles. Furthermore, we demonstrated micro-scale organic complementary inverters on a flexible PET substrate using p-type pentacene and n-type copper hexadecafluorophthalocyanine materials.
N-type doping of Ge by As implantation and excimer laser annealing
Authors: Milazzo R. , Napolitani E. , Impellizzeri G. , Fisicaro G. , Boninelli S. , Cuscunà M. , De Salvador D. , Mastromatteo M. , Italia M. , La Magna A. , Fortunato G. , Priolo F. , Privitera V. , Carnera A.
Published: February 2014

The diffusion and activation of arsenic implanted into germanium at 40 keV with maximum concentrations below and above the solid solubility (8 × 1019 cm−3) have been studied, both experimentally and theoretically, after excimer laser annealing (λ = 308 nm) in the melting regime with different laser energy densities and single or multiple pulses. Arsenic is observed to diffuse similarly for different fluences with no out-diffusion and no formation of pile-up at the maximum melt depth. The diffusion profiles have been satisfactorily simulated by assuming two diffusivity states of As in the molten Ge and a non-equilibrium segregation at the maximum melt depth. The electrical activation is partial and decreases with increasing the chemical concentration with a saturation of the active concentration at 1 × 1020 cm−3, which represents a new record for the As-doped Ge system.
An investigation of low temperature electronic phase arrest in Sm0.55Sr0.45MnO3 phase separated manganite
Authors: Giri S. K. , Nath T. K.
Published: February 2014

The temperature dependence of electronic-transport and magneto-transport of polycrystalline Sm0.55Sr0.45MnO3 manganite at low temperatures has been investigated in detail. The low temperature resistivity data show a distinct minimum in the resistivity versus temperature plots for all fields. The low temperature resistivity upturn below this minimum has been fitted to an expression, which includes three terms, namely, residual resistivity, inelastic scattering, and electron-electron (e-e) interaction or Kondo effects. It has been found that the dominating mechanism is e-e interaction. The resistivity of the sample shows strong dependence on the magnetic field–temperature history. The electronic-transport property clearly confirms that the electronic phase of the sample gets arrested to a low resistive state during field cooling and cannot return to its original state even after the magnetic field is removed. The magnetoresistance of the sample also shows a strong irreversibility with respect to the sweeping of the magnetic field between its highest positive and negative values. Moreover, the resistivity of the sample is found to be time dependent. All the observed phenomena have been explained through the phase separation scenario and kinetic arrest of electronic phase.
High magnetization Fe-Co and Fe-Ni submicron and nanosize particles by thermal decomposition and hydrogen reduction
Authors: Cui B. Z. , Marinescu M. , Liu J. F.
Published: February 2014

This paper reports morphology, structure, and magnetic properties of air-stable soft magnetic FexCo100−x (x = 65, 50, and 34) and Fe50Ni50 (at. %) submicron and nanosize particles fabricated by template-free thermal decomposition of nitrates of Fe, Co, and Ni and subsequent hydrogen reduction. The particle compositions were tuned by modification of the precursor solution concentrations. The as-synthesized Fe-Co and Fe50Ni50 particles have body centered cubic and face centered cubic poly-nanocrystalline structures, respectively. The Fe-Co and Fe50Ni50 particles have particle sizes in the range of 28–200 nm and 70–480 nm, and average grain sizes of 16–29 nm and 20–24 nm, respectively. The particle and grain sizes were controlled by tuning particle composition, and the temperature and time of hydrogen reduction. Saturation magnetization Ms as high as 207–224 emu/g and intrinsic coercivity Hci of 59–228 Oe were obtained in the Fe-Co particles reduced at 550 °C for 90 min. Of special note, the Ms of 224 emu/g (∼2.3 T) obtained in the Fe65Co35 particles is among the highest values for Fe-Co particles reported so far. Ms of 135–137 emu/g and Hci of 59–111 Oe were obtained in the Fe50Ni50 particles reduced at 500 or 550 °C for 20 min.
Strong coupling between excitons in organic semiconductors and Bloch surface waves
Authors: Pirotta Stefano , Patrini Maddalena , Liscidini Marco , Galli Matteo , Dacarro Giacomo , Canazza Giancarlo , Guizzetti Giorgio , Comoretto Davide , Bajoni Daniele
Published: February 2014

We report on the strong coupling between the Bloch surface wave supported by an inorganic multilayer structure and J-aggregate excitons in an organic semiconductor. The dispersion curves of the resulting polariton modes are investigated by means of angle-resolved attenuated total reflectance, as well as photoluminescence experiments. The measured Rabi splitting is 290 meV. These results are in good agreement with those obtained from our theoretical model.
Dielectric strength of parylene HT
Authors: Diaham S. , Bechara M. , Locatelli M.-L. , Khazaka R. , Tenailleau C. , Kumar R.
Published: February 2014

The dielectric strength of parylene HT (PA-HT) films was studied at room temperature in a wide thickness range from 500 nm to 50 μm and was correlated with nano- and microstructure analyses. X-ray diffraction and polarized optical microscopy have revealed an enhancement of crystallization and spherulites development, respectively, with increasing the material thickness (d). Moreover, a critical thickness dC (between 5 and 10 μm) is identified corresponding to the beginning of spherulite developments in the films. Two distinct behaviors of the dielectric strength (FB) appear in the thickness range. For d ≥ dC, PA-HT films exhibit a decrease in the breakdown field following a negative slope (FB ∼ d−0.4), while for d < dC, it increases with increasing the thickness (FB ∼ d0.3). An optimal thickness doptim ∼ 5 μm corresponding to a maximum dielectric strength (FB ∼ 10 MV/cm) is obtained. A model of spherulite development in PA-HT films with increasing the thickness is proposed. The decrease in FB above dC is explained by the spherulites development, whereas its increase below dC is induced by the crystallites growth. An annealing of the material shows both an enhancement of FB and an increase of the crystallites and spherulites dimensions, whatever the thickness. The breakdown field becomes thickness-independent below dC showing a strong influence of the nano-scale structural parameters. On the contrary, both nano- and micro-scale structural parameters appear as influent on FB for d ≥ dC.
Resolvent estimates for perturbations by large magnetic potentials
Authors: Cardoso Fernando , Cuevas Claudio , Vodev Georgi
Published: February 2014

We prove optimal high-frequency resolvent estimates for self-adjoint operators of the form G = −Δ + ib(x) · ∇ + i∇ · b(x) + V(x) on L2(Rn), n ⩾ 3, where b(x) and V(x) are large magnetic and electric potentials, respectively. No continuity of the magnetic potential is assumed.
Temperature dependence of abnormal grain growth and high magnetostriction in Goss-oriented Fe-Al thin sheets
Authors: Na Suok-Min , Flatau Alison B.
Published: February 2014

In this paper, we investigate grain growth behaviors in Fe-Al-NbC rolled sheets annealed under a sulfur atmosphere at temperatures of 1000–1300 °C for NbC additions of 0.75%, 1.0%, and 1.5%. In Fe80Al20 sheet plus 0.75% NbC, abnormal grain growth (AGG) occurred at higher temperature than 1150 °C. Large single (011) grains that covered 74%–90% of sample surface were fully grown at temperatures of 1200–1300 °C. For these samples, the remaining 10%–26% of the surface was comprised of small isolated island-like grains that were dispersed throughout the single grain Goss matrix. The single-grain-oriented Fe-Al sheet sample annealed at 1250 °C for 5 h exhibited magnetostriction of 133 ppm along the rolling direction (RD). A maximum magnetostriction value of 143 ppm along the RD was obtained in samples annealed at 1200 °C for 24 h. Of particular interest is that the magnetostriction response along ⟨100⟩ in these samples shows 177 ppm, approaching ∼94.4% of the magnetostrictive performance of single crystal at 19.5 at. % Al. In addition, we observed that the temperature at which the onset of AGG occurred increased with increasing the NbC content, which can be explained by an enhanced particle pinning force.
Spin correlated dielectric memory and rejuvenation in multiferroic CuCrS2
Authors: Karmakar A. , Dey K. , Chatterjee S. , Majumdar S. , Giri S.
Published: February 2014

We report a rare consequence of memory effect in dielectric response (ϵ) and magnetic field induced rejuvenation in a relaxor-type multiferroic chalcogenide, CuCrS2. Despite reasonably high conductivity, we are able to detect significant spontaneous polarization using an improvised technique verifying ferroelectric (FE) order. Concomitant appearance of both FE and antiferromagnetic orders authenticates multiferroicity. A smeared out FE transition and strong frequency dependence of the broadened peak in ϵ obeying Dynamical scaling law signify relaxor properties. We discuss the role of geometrical frustration in the antiferromagnetically coupled layered triangular lattice and metal ligand hybridization for these unusual properties.
Two counter-propagating He plasma plumes and ignition of a third plasma plume without external applied voltage
Authors: Wu S. , Lu X.
Published: February 2014

In this work, the interaction of the two counter-propagating helium plasma plume inside a dielectric tube is investigated. When voltages applied to the two electrodes are the same, a dark zone always occurs no matter if the electrodes are symmetric or not. The length of the dark zone decreases from 6 mm to 2 mm when the voltages applied to the two electrodes are increased from 5.5 kV to 7.5 kV. Then with the increase of the applied voltage up to 9 kV, the length of the dark zone becomes stable and approaches to a const value of 1.8 mm. On the other hand, when the voltages applied to the two electrodes are different, instead of a dark zone, a third plasma plume is generated between the upstream and downstream plasma plumes. Detailed studies found that the third plasma plume is ignited more than 300 ns after the voltage is off, it is the difference of the local space charges of the heads of the downstream plasma and the upstream plasma induces the local electric field, which ignites the plasma rather than the external applied voltages.
Phonon spectrometry goes nanoscale
Authors: Smart Ashley G.
Published: February 2014

The ability to probe phonon–surface scattering could help elucidate the curious thermal behavior of some nanostructured materials.
Beneficial impacts of climate change on pastoral and broadacre agriculture in cool-temperate Tasmania
Authors: Phelan D. C. , Parsons D. , Lisson S. N. , Holz G. K. , MacLeod N. D.
Published: February 2014

Although geographically small, Tasmania has a diverse range of regional climates that are affected by different synoptic influences. Consequently, changes in climate variables and climate-change impacts will likely vary in different regions of the state. This study aims to quantify the regional effects of projected climate change on the productivity of rainfed pastoral and wheat crop systems at five sites across Tasmania. Projected climate data for each site were obtained from the Climate Futures for Tasmania project (CFT). Six General Circulation Models were dynamically downscaled to ~10-km grid cells using the CSIRO Conformal Cubic Atmospheric Model under the A2 emissions scenario for the period 1961–2100. Mean daily maximum and minimum temperatures at each site are projected to increase from a baseline period (1981–2010) to 2085 (2071–2100) by 2.3–2.7°C. Mean annual rainfall is projected to increase slightly at all sites. Impacts on pasture and wheat production were simulated for each site using the projected CFT climate data. Mean annual pasture yields are projected to increase from the baseline to 2085 largely due to an increase in spring pasture growth. However, summer growth of temperate pasture species may become limited by 2085 due to greater soil moisture deficits. Wheat yields are also projected to increase, particularly at sites presently temperature-limited. This study suggests that increased temperatures and elevated atmospheric CO2 concentrations are likely to increase regional rainfed pasture and wheat production in the absence of any significant changes in rainfall patterns.
Association of trace elements and dissolution rates of soil iron oxides
Authors: Ketrot D. , Suddhiprakarn A. , Kheoruenromne I. , Singh B.
Published: February 2014

In this study, nine Oxisols and five Ultisols from Thailand were used to determine the association of major and trace elements with iron (Fe) oxides. The Fe oxides were concentrated and the association of elements (Al, Ca, Cu, Cr, Mg, Mn, Ni, Pb, P, Si, V, Ti, Zn) with Fe was evaluated using batch dissolution in 1 m HCl at 20°C. The dissolution behaviour of Fe oxide concentrates was determined using batch dissolution and flow-through reactors. In addition to Fe, both Al and Ti were present in significant amounts in the Fe oxide concentrates. Manganese was the most abundant trace element, and Cu, Zn, Pb and As concentrations were <250 mg kg–1 in most samples. The dissolution behaviour of Fe-oxide concentrates indicated that Al, Cr and V were mostly substituted for Fe3+ in the structure of goethite and hematite. A significant proportion of Mn, Ni, Co, Pb and Si was also present within the structure of these minerals. Some Mg, Cu, Zn, Ti and Ca was also associated with Fe oxides. The dissolution kinetics of Fe oxide concentrates was well described by three models, i.e. the cube root law, Avrami–Erofejev equation and Kabai equation, with the dissolution rate constants (103k) corresponding to the three models ranging from 0.44 to 6.11 h–1, from 1.01 to 4.40 h–1 and from 0.03 to 4.12 h–1, respectively. The k constants of Fe oxide concentrates in this study were significantly and negatively correlated with the mean crystal dimension derived from [110] and [104] of hematite, the dominant mineral in most samples. The steady-state dissolution rate of a soil Fe-oxide concentrate (sample Kk) was substantially higher than for synthetic goethite under highly acidic conditions; this is possibly due to the greater specific surface area of sample Kk than the synthetic goethite.
Comparison of the penetration of primary and lateral roots of pea and different tree seedlings growing in hard soils
Authors: Azam Gausul , Grant Cameron D. , Murray Robert S. , Nuberg Ian K. , Misra Rabindra K.
Published: February 2014

Establishment and survival of tree seedlings in hard soils depends on production of deep root systems. This study evaluated the primary and lateral roots of an annual crop and several tree species growing in soils of varying strength. We grew peas and acacias by direct seeding, plus three eucalypts by direct seeding and transplanting, and measured various root characteristics. At all levels of soil compaction, the primary roots of acacia were thicker and they elongated faster than did those of the eucalypts. However, lateral roots of transplanted eucalypts elongated faster than their primary roots, and the rate of root elongation was negatively correlated with soil penetration resistance, especially for Eucalyptus camaldulensis. The primary root diameter of all plants increased with increasing penetration resistance, but acacia roots continued to elongate faster than pea roots. Pea plants produced most of their roots in the top 5 cm, whereas tree roots were more uniformly distributed with depth. Although not statistically significant at P = 0.05, the relative rate of root elongation in very hard soil correlated modestly (P = 0.11) with the maximum root growth pressure of four tree species. These variations in root growth behaviour can be related to the intrinsic variability of root characteristics for each plant species and the natural abundance of each species in different environments.
A disulfide tether stabilizes the block of sodium channels by the conotoxin μO§-GVIIJ
Authors: Gajewiak Joanna , Azam Layla , Imperial Julita , Walewska Aleksandra , Green Brad R. , Bandyopadhyay Pradip K. , Raghuraman Shrinivasan , Ueberheide Beatrix , Bern Marshall , Zhou H. Mimi , Minassian Natali A. , Hagan Rebecca H. , Flinspach Mack , Liu Yi , Bulaj Grzegorz , Wickenden Alan D. , Olivera Baldomero M. , Yoshikami Doju , Zhang Min-Min
Published: February 2014

Significance

A biochemically unique cone snail venom peptide has been characterized that may be used to probe unexplored but important features of the diverse voltage-gated Na channel isoforms that underlie electrical signaling in the nervous system. This peptide has a unique posttranslational modification (S-cysteinylated cysteine) and blocks sodium channels by forming a disulfide bond with the channel at a distinctive binding site. Because block by the peptide is prevented when specific β-subunits are coexpressed, this neurotoxin has potential for assessing which β-subunits are present in native Na channels. Peptide activity depends on the oxidation state of extracellular Cys residues on the channel. Thus, this peptide can also be used to monitor the oxidation state of the targeted Na channels.
Assisting Our Brothers, Defending Ourselves: The Iranian Intervention in Oman, 1972–75
Authors: Goode James F.
Published: February 2014

The Iranian military intervention in Oman (1972–75) proved to be one of Shah Mohammad Reza Pahlavi's most successful foreign policy initiatives. He entered at the request of Sultan Qabus to help quell the Marxist rebellion of the Popular Front for the Liberation of Oman in Dhufar province. The shah took this action without any prior consultation with either Britain or the United States, acting for reasons wholly related to Iran's regional security. In so doing, he angered most of his Arab neighbors, who protested vigorously. He persisted. His troops tipped the balance in favor of the sultan's forces, contributing to a speedy end to the insurrection, for which Iran earned the lasting gratitude of the sultan.
Psychosocial Interventions, Peacebuilding and Development in Rwanda
Authors: Lambourne Wendy , Gitau Lydia Wanja
Published: February 2014

Post-conflict peacebuilding has been criticised as being too focused on macro-level economic development and institutional reform at the expense of a more people-centred, service-oriented process that promotes the transformation in relationships and life conditions necessary to support a sustainable peace. This article suggests that the essence of peace and the capacity for development at the individual and community level are being lost in the dominant state-centric model of peacebuilding. It also suggests that psychosocial services that address the need for individual and community capacity-building should be seen as an integral part of social services where people are struggling to engage meaningfully in life after experiencing mass violence. Using Rwanda as a case study, it argues for a greater emphasis on psychosocial interventions as part of a more holistic and transformative approach to peacebuilding that promotes resilience, social cohesion and sustainable development.
‘Buying Peace’ in Chechnya: Challenges of Post-Conflict Reconstruction in the Public Sector
Authors: Zabyelina Yuliya G.
Published: February 2014

Whereas there seems to be a consensus on the importance of social services for the success of peacebuilding efforts, the role of corruption in the public sector remains ambiguous. On the one hand, conventional interpretations of the role of corruption in the aftermath of conflict suggest that corruption impedes a successful war-to-peace transition. On the other hand, corruption may be necessary to the survival of ordinary citizens by reinforcing economic efficiency and helping them to gain access to basic social services. This article studies various aspects of post-conflict reconstruction in Chechnya with a particular focus on corruption in in the public sector. It argues that Moscow's strategy of soothing the insurgency in the North Caucasus with generous financial injections has brought some stability at least in the sense of absence of large-scale violence. Despite these seemingly positive results, sweeping corruption in the public sector is likely to undermine the effectiveness of post-conflict reconstruction and development projects in Chechnya in the long run, in this way increasing the likelihood of post-conflict Chechen society sliding back into public discontent and violence.
Must Our Communities Bleed to Receive Social Services? Development projects and collective reparations schemes in colombia
Authors: Firchow Pamina
Published: February 2014

The provision of social services in protracted conflicts, such as the Colombian conflict, is scarce and sometimes non-existent. Collective reparations are normally composed of restitution, compensation, rehabilitation and guarantees of no repetition. They constitute what normally would encompass development projects and can provide basic social services in contexts of peace and stability with additional symbolic and psychosocial elements. After more than five decades of conflict in Colombia, it seems that significant political will for transitional justice programmes — and in particular, reparations programmes — has emerged with the 2010 election of President Juan Manuel Santos and the ratification of the 2011 Victim's Law. In 2007, a pilot project of collective reparations programmes was initiated with the support of international development agencies. This paper uses data collected from these pilot projects to demonstrate the complexity of introducing development projects as a form of reparations in conflict-affected communities. It also questions whether it is good policy to require communities to have to ‘bleed first’ to receive basic social services under the auspices of collective reparations and explores the possible problems involved in implementing collective reparations programmes without a comprehensive development policy in post-conflict contexts.