bluuebunny/crossref_metadata_2025 huggingface dataset:
Structure and stability of steady porous medium convection at large Rayleigh number
Authors: Wen Baole , Corson Lindsey T. , Chini Gregory P.
Published: May 2015

A systematic investigation of unstable steady-state solutions of the Darcy–Oberbeck–Boussinesq equations at large values of the Rayleigh number $\mathit{Ra}$ is performed to gain insight into two-dimensional porous medium convection in domains of varying aspect ratio $L$. The steady convective states are shown to transport less heat than the statistically steady ‘turbulent’ flow realised at the same parameter values: the Nusselt number $\mathit{Nu}\sim \mathit{Ra}$ for turbulent porous medium convection, while $\mathit{Nu}\sim \mathit{Ra}^{0.6}$ for the maximum heat-transporting steady solutions. A key finding is that the lateral scale of the heat-flux-maximising solutions shrinks roughly as $L\sim \mathit{Ra}^{-0.5}$, reminiscent of the decrease of the mean inter-plume spacing observed in turbulent porous medium convection as the thermal forcing is increased. A spatial Floquet analysis is performed to investigate the linear stability of the fully nonlinear steady convective states, extending a recent study by Hewitt et al. (J. Fluid Mech., vol. 737, 2013, pp. 205–231) by treating a base convective state, and secondary stability modes, that satisfy appropriate boundary conditions along plane parallel walls. As in that study, a bulk instability mode is found for sufficiently small-aspect-ratio base states. However, the growth rate of this bulk mode is shown to be significantly reduced by the presence of the walls. Beyond a certain critical $\mathit{Ra}$-dependent aspect ratio, the base state is most strongly unstable to a secondary mode that is localised near the heated and cooled walls. Direct numerical simulations, strategically initialised to investigate the fully nonlinear evolution of the most dangerous secondary instability modes, suggest that the (long time) mean inter-plume spacing in statistically steady porous medium convection results from a balance between the competing effects of these two types of instability.
Protestant conversion and social conflict: The case of the Hmong in contemporary Vietnam
Authors: Ngo Tam T.T.
Published: May 2015

This article analyses the social implications of the recent mass conversions to Protestantism by one-third of the one million Hmong in Vietnam. The conversions have been condemned by the Vietnamese state, while being understood by international human rights activists as acts of conscience on the part of the Hmong converts. This article focuses on the internal debate and divisions surrounding conversion among the Hmong themselves. The converts believe that Protestantism is the only way to alter the ethnic group's marginal status in Vietnam while the unconverted Hmong see conversion as a betrayal of Hmong ethnicity. Such conflicting views have been causing deep fractures in Hmong society.
HECKE ALGEBRAS FOR INNER FORMS OF -ADIC SPECIAL LINEAR GROUPS
Authors: Aubert Anne-Marie , Baum Paul , Plymen Roger , Solleveld Maarten
Published: May 2015

Let$F$be a non-Archimedean local field, and let$G^{\sharp }$be the group of$F$-rational points of an inner form of$\text{SL}_{n}$. We study Hecke algebras for all Bernstein components of$G^{\sharp }$, via restriction from an inner form$G$of$\text{GL}_{n}(F)$.

For any packet of L-indistinguishable Bernstein components, we exhibit an explicit algebra whose module category is equivalent to the associated category of complex smooth$G^{\sharp }$-representations. This algebra comes from an idempotent in the full Hecke algebra of$G^{\sharp }$, and the idempotent is derived from a type for$G$. We show that the Hecke algebras for Bernstein components of$G^{\sharp }$are similar to affine Hecke algebras of type$A$, yet in many cases are not Morita equivalent to any crossed product of an affine Hecke algebra with a finite group.
Surface Folds Hint at Magnitude of Slip Along Thrust Faults
Authors: Rosen Julia
Published: May 2015

The shape of deformed sediments at the surface may allow researchers to estimate the cumulative slip along thrust faults such as the Chelungpu fault in Taiwan.
Honors and Appointments
Authors:   AGU
Published: May 2015

Earth and space scientists in the news
The decomposition of fine and coarse roots: their global patterns and controlling factors
Authors: Zhang Xinyue , Wang Wei
Published: May 2015

Fine root decomposition represents a large carbon (C) cost to plants and serves as a potential soil C source, as well as a substantial proportion of net primary productivity. Coarse roots differ markedly from fine roots in morphology, nutrient concentrations, functions and decomposition mechanisms. Still poorly understood is whether a consistent global pattern exists between the decomposition of fine (<2 mm root diameter) and coarse (≥2 mm) roots. A comprehensive terrestrial root decomposition dataset, including 530 observations from 71 sampling sites, was thus used to compare global patterns of decomposition of fine and coarse roots. Fine roots decomposed significantly faster than coarse roots in middle latitude areas, but their decomposition in low latitude regions was not significantly different from that of coarse roots. Coarse root decomposition showed more dependence on climate, especially mean annual temperature (MAT), than did fine roots. Initial litter lignin content was the most important predictor of fine root decomposition, while lignin to nitrogen ratios, MAT and mean annual precipitation were the most important predictors of coarse root decomposition. Our study emphasizes the necessity of separating fine roots and coarse roots when predicting the response of belowground C release to future climate changes.
The Tomato yellow leaf curl virus V2 protein forms aggregates depending on the cytoskeleton integrity and binds viral genomic DNA
Authors: Moshe Adi , Belausov Eduard , Niehl Annette , Heinlein Manfred , Czosnek Henryk , Gorovits Rena
Published: May 2015

The spread of Tomato yellow leaf curl virus (TYLCV) was accompanied by the formation of coat protein (CP) aggregates of increasing size in the cytoplasm and nucleus of infected tomato (Solanum lycopersicum) cells. In order to better understand the TYLCV-host interaction, we investigated the properties and the subcellular accumulation pattern of the non-structural viral protein V2. CP and V2 are the only sense-oriented genes on the virus circular single-stranded DNA genome. Similar to CP, V2 localized to cytoplasmic aggregates of increasing size and as infection progressed was also found in nuclei, where it co-localized with CP. V2 was associated with viral genomic DNA molecules, suggesting that V2 functions as a DNA shuttling protein. The formation and the 26S proteasome-mediated degradation of V2 aggregates were dependent on the integrity of the actin and microtubule cytoskeleton. We propose that the cytoskeleton-dependent formation and growth of V2 aggregates play an important role during TYLCV infection and that microtubules and actin filaments are important for the delivery of V2 to the 26S proteasome.
A rapid single column separation scheme for high-precision Sr–Nd–Pb isotopic analysis in geological samples using thermal ionization mass spectrometry
Authors: Li Chao-Feng , Chu Zhu-Yin , Guo Jing-Hui , Li You-Lian , Yang Yue-Heng , Li Xiang-Hui
Published: May 2015

In this study, a single-column separation scheme is compared with the traditional three-step separation procedure.
Potassium modified layered Ln2O2CO3 (Ln: La, Nd, Sm, Eu) materials: efficient and stable heterogeneous catalysts for biofuel production
Authors: Zhang Yashan , Jin Lei , Sterling Kevin , Luo Zhu , Jiang Ting , Miao Ran , Guild Curtis , Suib Steven L.
Published: May 2015

Potassium modified layered Ln2O2CO3 catalysts were prepared for transesterification with high FAME yield under mild reaction conditions.
An elastography analytical method for the rapid detection of endotoxin
Authors: Sun Haixuan , Miao Peng , Tang Yuguo , Wang Bidou , Qian Jun , Wang Danyi
Published: May 2015

A flexible analytical method that records elastography (EG) is used to study coagulation systems and the rapid detection of endotoxin is achieved by the EG analysis of endotoxin-induced limulus amebocyte lysate coagulation.
Optical gain from polyfluorene keto defects in a liquid crystal mixture
Authors: Bolis S. , Celebrano M. , Ghirardini L. , Finazzi M. , Botta C. , Beeckman J. , Kockaert P. , Virgili T.
Published: May 2015

Confocal photoluminescence measurements and fs pump–probe spectroscopy to observe a polarized gain region from keto defects in polyfluorene isolated chains.
Catalytic, oxidant-free, direct olefination of alcohols using Wittig reagents
Authors: Khaskin E. , Milstein D.
Published: May 2015

Catalytic acceptorless coupling of alcohols with in situ generated phosphonium ylides forms olefins and H2, with significant stereospecificity.
First principles study of magnetoelectric coupling in Co2FeAl/BaTiO3 tunnel junctions
Authors: Yu Li , Gao Guoying , Zhu Lin , Deng Lei , Yang Zhizong , Yao Kailun
Published: May 2015

Critical thickness for ferroelectricity and the magnetoelectric effect of Co2FeAl/BaTiO3 multiferroic tunnel junctions (MFTJs) are investigated using first-principles calculations.
Iridium-based complexes for water oxidation
Authors: Thomsen Julianne M. , Huang Daria L. , Crabtree Robert H. , Brudvig Gary W.
Published: May 2015

Activation of organometallic Ir precatalysts can yield either homogeneous or heterogeneous water-oxidation catalysts with very high activity.
A mechanistic investigation of the ruthenium porphyrin catalysed aziridination of olefins by aryl azides
Authors: Zardi P. , Pozzoli A. , Ferretti F. , Manca G. , Mealli C. , Gallo E.
Published: May 2015

A combination of DFT and kinetic studies suggests a mechanism for olefin aziridination by organic azides catalysed by ruthenium porphyrins.
Alkyne substituted mononuclear photocatalysts based on [RuCl(bpy)(tpy)]+
Authors: Davidson Ross J. , Wilson Lucy E. , Duckworth Andrew R. , Yufit Dmitry S. , Beeby Andrew , Low Paul J.
Published: May 2015

The introduction of ‘wire-like’ arylene ethynylene substituent to the prototypical water oxidation catalyst precursor [RuCl(2,2′-bipyridine)(2,2′:6′,2′′-terpyridine)]PF6does not significantly alter the photostability of the compounds, nor the ability of the complexes to oxidise 4-methoxybenzyl alcohol to 4-methoxybenzaldehyde.
A MALDI-TOF MS analysis study of the binding of 4-(N,N-dimethylamino)pyridine to amine-bis(phenolate) chromium(iii) chloride complexes: mechanistic insight into differences in catalytic activity for CO2/epoxide copolymerization
Authors: Kozak Christopher M. , Woods April M. , Bottaro Christina S. , Devaine-Pressing Katalin , Ni Kaijie
Published: May 2015

Amine-bis(phenolato)chromium(iii) chloride complexes, [LCrCl], are capable of catalyzing the copolymerization of cyclohexene oxide with carbon dioxide to give poly(cyclohexane) carbonate. When combined with 4-(N,N-dimethylamino)pyridine (DMAP) these catalyst systems yield low molecular weight polymers with moderately narrow polydispersities. The coordination chemistry of DMAP with five amine-bis(phenolato)chromium(iii) chloride complexes was studied by matrix assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). The amine-bis(phenolato) ligands were varied in the nature of their neutral pendant donor-group and include oxygen-containing tetrahydrofurfuryl and methoxyethyl moieties, or nitrogen-containing N,N-dimethylaminoethyl or 2-pyridyl moieties. The relative abundance of mono and bis(DMAP) adducts, as well as DMAP-free ions is compared under various DMAP : Cr complex ratios. The [LCr]+ cations show the ability to bind two DMAP molecules to form six-coordinate complex ions in all cases, except when the pendant group is N,N-dimethylaminoethyl (compound 3). Even in the presence of a 4 : 1 ratio of DMAP to Cr, no ions corresponding to [L3Cr(DMAP)2]+ were observed for the complex containing the tertiary sp3-hybridized amino donor in the pendant arm. The difference in DMAP-binding ability of these compounds results in differences in catalytic activity for alternating copolymerization of CO2 and cyclohexene oxide. Kinetic investigations by infrared spectroscopy of compounds 2 and 3 show that polycarbonate formation by 3 is twice as fast as that of compound 2 and that no initiation time is observed.
Uncatalysed diaryldiazo cyclopropanations on bicyclic lactams: access to annulated prolines
Authors: Harris Lawrence , Gilpin Martin , Thompson Amber L. , Cowley Andrew R. , Moloney Mark G.
Published: May 2015

The uncatalysed cycloaddition of substituted diaryldiazo compounds onto bicyclic unsaturated lactams derived from pyroglutamic acid efficiently leads to highly functionalised azatricyclononanes.
A novel heterogeneous hybrid by incorporation of Nb2O5 microspheres and reduced graphene oxide for photocatalytic H2 evolution under visible light irradiation
Authors: Yue Zongkuan , Chu Dongmei , Huang Hui , Huang Jie , Yang Ping , Du Yukou , Zhu Mingshan , Lu Cheng
Published: May 2015

A novel heterogeneous hybrid composed of Nb2O5 microspheres and reduced graphene oxide as photocatalyst exhibits superior photocatalytic activity and stability.
Modular construction of multifunctional ligands for the enantioselective ruthenium-catalyzed carbenoid N–H insertion reaction: an enzyme-like and substrate-sensitive catalyst system
Authors: Huang Wei-Sheng , Xu Zheng , Yang Ke-Fang , Chen Li , Zheng Zhan-Jiang , Xu Li-Wen
Published: May 2015

It was found for the first time that BINOL-derived multifunctional ligands bearing a silicon-based bulky group exhibited promising enantioselective control in the ruthenium-catalysed carbenoid N–H insertion reaction.
A multifunctional molecular entity CuII–SnIV heterobimetallic complex as a potential cancer chemotherapeutic agent: DNA binding/cleavage, SOD mimetic, topoisomerase Iα inhibitory and in vitro cytotoxic activities
Authors: Tabassum Sartaj , Asim Ahmad , Khan Rais Ahmad , Arjmand Farukh , Rajakumar Dhivya , Balaji Perumalsamy , Akbarsha Mohammad Abdulkader
Published: May 2015

New chiral l-valine-derived Schiff base complexes with the bioactive heterocyclic ligand scaffold pyrazole (Hpz) were designed and synthesized with a view to find their potential as anticancer chemotherapeutic drug candidates.
Low temperature ionic conductor: ionic liquid incorporated within a metal–organic framework
Authors: Fujie Kazuyuki , Otsubo Kazuya , Ikeda Ryuichi , Yamada Teppei , Kitagawa Hiroshi
Published: May 2015

An ionic liquid incorporated into micropores of a metal–organic framework showed higher ionic conductivity than bulk ionic liquid at low temperature because of the absence of marked freezing transition.
Enhanced electrochemical performance of hierarchical CoFe2O4/MnO2/C nanotubes as anode materials for lithium-ion batteries
Authors: Zhou Junjie , Yang Ting , Mao Minglei , Ren Weiji , Li Qiuhong
Published: May 2015

We report a facile preparation of MnO2 nanosheet-coated CoFe2O4 nanofibers containing carbon for lithium ion batteries. The CoFe2O4/MnO2/C nanotubes exhibit a reversible capacity of 713.6 mA h g−1 at 100 mA g−1 after 250 cycles.
Hybrid nanostructured hydroxyapatite–chitosan composite scaffold: bioinspired fabrication, mechanical properties and biological properties
Authors: Guo Ya-Ping , Guan Jun-Jie , Yang Jun , Wang Yang , Zhang Chang-Qing , Ke Qin-Fei
Published: May 2015

A bioinspired strategy has been developed to fabricate a hybrid nanostructured hydroxyapatite–chitosan composite scaffold for bone tissue engineering.
Speech, Spatial and Qualities of Hearing Scale (SSQ) and Spatial Hearing Questionnaire (SHQ) Changes Over Time in Adults With Simultaneous Cochlear Implants
Authors: Zhang Juan , Tyler Richard , Ji Haihong , Dunn Camille , Wang Ningyu , Hansen Marlan , Gantz Bruce
Published: May 2015

Purpose

The purpose of the present study is to evaluate the changes over time of the Spatial Hearing Questionnaire (SHQ; Tyler, Perreau, & Ji, 2009) and the Speech, Spatial and Qualities of Hearing Scale (SSQ; Gatehouse & Noble, 2004) in adults with simultaneous bilateral cochlear implants by collecting data for 2 years after implantation.

Method

Nineteen postlingual subjects participated in this study. Average age at implant was 63 years. The subjects' data were included in this retrospective analysis only if they completed both questionnaires. We compared subjects' SSQ and SHQ scores to word recognition and sound localization performances.

Results

The study showed SHQ and SSQ scores continuously improved up to 1 year postimplantation, with the most improvement occurring within the first 6 months of implantation. After 1 year, the scores reached a plateau. This is consistent with laboratory tests from the same 19 subjects, and they showed high correlations (
p
< .05). The present study also showed a high degree of correlation between SHQ and SSQ scores.

Conclusions

Both the SSQ and SHQ scores improved up to 12 months postimplantation, with the most improvement during the first 6 months of implantation. Both were consistent with laboratory tests. There was a high degree of correlation between SHQ and SSQ scores.
Managing the move to the cloud – analyzing the risks and opportunities of cloud-based accounting information systems
Authors: Asatiani Aleksandre , Penttinen Esko
Published: May 2015

The accounting industry is being disrupted by the introduction of cloud-based accounting information systems (AIS) that allow for a more efficient allocation of work between the accountant and the client company. In cloud-based AIS, the accountant and the client company as well as third parties such as auditors can simultaneously work on the data in real time. This, in turn, enables a much more granular division of work between the parties. This teaching case considers Kluuvin Apteekki, a small pharmacy business whose owner faces critical management decisions on how to embrace this new opportunity to move to the cloud. Students are guided to evaluate the advantages and drawbacks of cloud computing in the specific context of accounting services. Also, the owner must make a set of critical decisions concerning which tasks to outsource. The accounting process comprises of several tasks and sub-tasks, adding to the complexity of the decision making problem. The main learning outcome of the case is related to the development of the skills and competencies needed in creating a strong business case for implementing IT-enabled business processes.
Temperature-induced sign change of the magnetic interlayer coupling in Ni/Ni25Mn75/Ni trilayers on Cu3Au(001)
Authors: Shokr Y. A. , Erkovan M. , Wu C.-B. , Zhang B. , Sandig O. , Kuch W.
Published: May 2015

We investigated the magnetic interlayer coupling between two ferromagnetic (FM) Ni layers through an antiferromagnetic (AFM) Ni25Mn75 layer and the influence of this coupling on the exchange bias phenomenon. The interlayer coupling energy of an epitaxial trilayer of 14 atomic monolayers (ML) Ni/45 ML Ni25Mn75/16 ML Ni on Cu3Au(001) was extracted from minor-loop magnetization measurements using in-situ magneto-optical Kerr effect. The interlayer coupling changes from ferromagnetic to antiferromagnetic when the temperature is increased above 300 K. This sign change is interpreted as the result of the competition between an antiparallel Ruderman-Kittel-Kasuya-Yosida (RKKY)-type interlayer coupling, which dominates at high temperature, and a stronger direct exchange coupling across the AFM layer, which is present only below the Néel temperature of the AFM layer.
Effect of excluded volume on the rheology and transport dynamics of randomly hyperbranched polymers
Authors: Rai Gobind Ji , Kumar Amit , Biswas Parbati
Published: May 2015

The rheology and transport dynamics of the randomly hyperbranched polymers with excluded volume interactions are investigated within the tenets of the Rouse-Zimm theory. The excluded volume interactions typically account for an effective co-volume between the nearest non-bonded monomers, modeled through a delta function pseudopotential, while the strength of such interactions is evaluated from the possible geometric orientations of the bonds. The mechanical moduli are primarily determined by the smaller eigenvalues corresponding to the collective modes. These modes with smaller relaxation rates increase with the decrease in the strength of excluded volume interaction parameter, while the local modes with higher relaxation rates remain unaffected. The internal structure of the randomly hyperbranched polymer is reflected in the intermediate frequency regime of the mechanical relaxation moduli, where the characteristic power-law behavior implies the fractal nature of the randomly hyperbranched polymers. The length of this power-law region increases either with the decrease in the strength of excluded volume interactions or with the increase in the number of shells of the randomly hyperbranched polymer, while the numerical values of the power-law exponents are strongly affected by the strength of excluded volume interactions. Intrinsic viscosity increases linearly for lower values of the excluded volume interaction parameters, while depicting a non-linear trend at higher strengths of excluded volume interactions. The randomly hyperbranched polymers are relatively more compact compared to the star polymer but less compact than that of dendrimers with the same number of monomers and same strength of excluded volume interactions. The values of the scaling exponents of the diffusion coefficient increase with decreasing the strength of excluded volume interactions. The scaling exponents of the diffusion coefficient of randomly hyperbranched polymers calculated with excluded volume exactly match with the earlier experimental results for hyperbranched polyglycidols in poly(vinyl alcohol) solutions.
Lattice dynamics and chemical bonding in Sb2Te3 from first-principles calculations
Authors: Wang Bao-Tian , Souvatzis Petros , Eriksson Olle , Zhang Ping
Published: May 2015

Pressure effects on the lattice dynamics and the chemical bonding of the three-dimensional topological insulator, Sb2Te3, have been studied from a first-principles perspective in its rhombohedral phase. Where it is possible to compare, theory agrees with most of the measured phonon dispersions. We find that the inclusion of relativistic effects, in terms of the spin-orbit interaction, affects the vibrational features to some extend and creates large fluctuations on phonon density of state in high frequency zone. By investigations of structure and electronic structure, we analyze in detail the semiconductor to metal transition at ∼2 GPa followed by an electronic topological transition at a pressure of ∼4.25 GPa.
Thermal transport in laminar flow over superhydrophobic surfaces, utilizing an effective medium approach
Authors: Moreira David , Bandaru Prabhakar R.
Published: May 2015

An analytical methodology to characterizing the effects of heat transport in internal laminar flows over ridged patterns, mimicking superhydrophobic surfaces, is indicated. The finite slip velocity on such surfaces and the thermal conductivity characteristics of the constituent material are both shown to modify the convective heat transport in the fluid. We use an effective medium approach to model the lowered thermal conductivity caused by the presence of air in the ridge interstices. The proposed analytical solutions for fully developed flow were verified through comparison with numerical simulations for a periodically ridged geometry in laminar flow. While the convective heat transport and the Nusselt Number (Nu) increase due to the modified fluid velocity profile on superhydrophobic surfaces, the decrease in the thermal conductivity of the substrate may play a larger role in determining the overall heat transfer in the channel.
A frequency and bandwidth tunable metamaterial absorber in x-band
Authors: Yuan H. , Zhu B. O. , Feng Y.
Published: May 2015

Smart control is an attracting and important function for modern electromagnetic wave absorber. This paper presents the design, fabrication, and measurement of a frequency and bandwidth tunable metamaterial absorber (MA) in X-band. The unit cell of the MA consists of a microstrip resonator loaded with the varactors. Simulation and measurement results show that by tuning the bias voltage on the varactors, the peak absorption frequency can be tuned by 0.44 GHz with the peak absorption greater than 95%. Field and circuit model analysis is conducted to reveal the working mode and predict the absorbing frequency. After that, by specially designing the bias circuit so as to adjust the bias voltage on neighboring unit cells separately, dual resonance and absorption peaks occur, and the overall absorption bandwidth can thus be tuned conveniently by controlling the difference of the two resonance frequencies. The center absorbing frequency can also be tuned. Simulation and experiment results show that the 75% absorption (−6 dB reflection) bandwidth can be tuned from 0.40 GHz to 0.74 GHz, which is a two-fold tuning range. This work is believed to improve the state-of-the-art smart metamaterial absorber.
Highly directive Fabry-Perot leaky-wave nanoantennas based on optical partially reflective surfaces
Authors: Lorente-Crespo M. , Mateo-Segura C.
Published: May 2015

Nanoantennas enhance the conversion between highly localized electromagnetic fields and far-field radiation. Here, we investigate the response of a nano-patch partially reflective surface backed with a silver mirror to an optical source embedded at the centre of the structure. Using full wave simulations, we demonstrate a two orders of magnitude increased directivity compared to the isotropic radiator, 50% power confinement to a 13.8° width beam and a ±16 nm bandwidth. Our antenna does not rely on plasmonic phenomena thus reducing non-radiative losses and conserving source coherence.
Magnetic properties of square Py nanowires: Irradiation dose and geometry dependence
Authors: Ehrmann A. , Blachowicz T. , Komraus S. , Nees M.-K. , Jakobs P.-J. , Leiste H. , Mathes M. , Schaarschmidt M.
Published: May 2015

Arrays of ferromagnetic patterned nanostructures with single particle lateral dimensions between 160 nm and 400 nm were created by electron-beam lithography. The fourfold particles with rectangular-shaped walls around a square open area were produced from permalloy. Their magnetic properties were measured using the longitudinal magneto-optical Kerr effect. The article reports about the angle-dependent coercive fields and the influence of the e-beam radiation dose on sample shapes. It is shown that a broad range of radiation dose intensities enables reliable creation of nanostructures with parameters relevant for the desired magnetization reversal scenario. The experimental results are finally compared with micromagnetic simulations to explain the findings.
Interfacial properties and their impact on magnetic tunnel junction at microwave frequencies
Authors: Zhao Y. P. , Hemour S. , Houssameddine D. , Bai L. H. , Gui Y. S. , Hu C. M. , Wu K.
Published: May 2015

An equivalent model for MgO-based magnetic tunnel junction (MTJ) is used to characterize the frequency behavior of MTJs up to 20 GHz in this paper. From the extracted parasitic factor of MTJ, we found that the parasitic components (beside the junction resistance) significantly yield adverse effect, especially at microwave frequencies. Full parametric studies show that the interfacial capacitance, rather than the geometric capacitance, plays a key role in the drop of efficiency in microwave frequency applications of MTJs. Interfacial resistance engineering is proposed as a solution to improve the parasitic factor, as well as the operation frequency of MTJ.
The role of phosphorus deficiency in nodule microbial composition, and carbon and nitrogen nutrition of a native legume tree in the Cape fynbos ecosystem
Authors: Magadlela Anathi , Vardien Waafeka , Kleinert Aleysia , Dreyer Léanne L. , Valentine Alexander J.
Published: May 2015

In phosphorus (P)-poor ecosystems, microbial communities can play a major role in the nitrogen (N) mineral nutrition during N2 fixation in legumes. This study investigated the role of P nutrition on the composition of N2-fixing bacterial community in Virgilia divaricata root nodules, grown under glasshouse conditions. V. divaricata seeds were germinated in Fynbos soil as a natural inoculum, and, thereafter, transferred into sterile quartz-sand cultures and supplied with 500 µM P and 5 µM P, respectively. The N2-fixing bacterial communities in the rhizosphere and root nodules were examined on the basis of the polymerase chain reaction–denaturing gradient gel electrophoresis (PCR–DGGE) banding patterns of 16S rDNA and sequencing methods. The GenBank blast results showed that V. divaricata was nodulated by a wide range of root-nodule bacterial strains also found in the rhizosphere. These included Burkholderia phytofirmans, Burkholderia sp. and Bradyrhizobium sp., during both high and low P supply. The 15N natural-abundance data also confirmed that 40–50% of the N nutrition was from symbiotic N2 fixation. This is not only evidence of nodulation, but an indication of the adaptation of a range of N2-fixing bacterial strain species to the nutrient-poor, sandy, acidic soil of the Mediterranean-type ecosystems of the fynbos vegetation in the Cape Floristic Region (CFR). Legume species V. divaricata is highly adapted to the low-nutrient soils of its native range by its association with the symbiotic N2-fixing bacteria.
Potential role of maternal lineage in the thoroughbred breeding strategy
Authors: Lin Xiang , Zhou Shi , Wen Li , Davie Allan , Yao Xinkui , Liu Wujun , Zhang Yong
Published: May 2015

Many studies have focused on identifying the genes or single nucleotide polymorphisms associated with the athletic ability of thoroughbreds, but few have considered differences in maternal and paternal heritability of athletic ability. Herein, we report on our association study of career race performances of 675 Australian thoroughbreds with their pedigrees. Racing performance data (prize money per start) were collected from the Bloodhound database. The performance of all horses was categorised as either poor or elite athletic achievement. Then, 675 foals were divided by their parents’ performance (elite or poor) into four groups: (1) elite dams and elite sires; (2) elite dams and poor sires; (3) poor dams and elite sires; and (4) poor dams and poor sires. The performance of foals was then compared between the four groups. The results show that the heritability of race performance between dams and foals (r = 0.141, P < 0.001) is much higher than that between sires and foals (r = 0.035, P = 0.366), and that this difference is statistically significant (P < 0.05). We also examined the effect of the child-bearing age of dams and sires on the ratio of elite foals. We found a strong correlation between the number of elite foals and dams’ child-bearing age (r = –0.105, P < 0.001), with the ratio of elite offspring reaching a high level between a child-bearing age of 8 and 11 years (χ2 = 14.31, d.f. = 1, P < 0.001). These findings suggest that the maternal line may play an important role in the selective breeding of athletic performance in thoroughbreds.
Tempo and mode of antibat ultrasound production and sonar jamming in the diverse hawkmoth radiation
Authors: Kawahara Akito Y. , Barber Jesse R.
Published: May 2015

Significance

Ultrasound production is one of the most sophisticated antibat strategies in nocturnal insects, yet it has never been thoroughly studied in a phylogenetic framework. We conducted high-throughput field assays using playback of echolocation attack sequences, laboratory bat–moth interaction experiments, and fossil-calibrated phylogenetic analyses to provide the first evidence that multiple unrelated hawkmoth species produce ultrasound and jam bat echolocation. Our robust tree demonstrates that sonar jamming evolved twice during the Miocene after the radiation of insectivorous bats. We provide an example of the power behind collaborative science for revealing the function and historic pattern of behavior, and predict that ultrasound production is a widespread antibat strategy in the extraordinary diversity of nocturnal insects.
G-protein βγ subunits are positive regulators of Kv7.4 and native vascular Kv7 channel activity
Authors: Stott Jennifer B. , Povstyan Oleksandr V. , Carr Georgina , Barrese Vincenzo , Greenwood Iain A.
Published: May 2015

Significance

The Kv7.4 potassium channel is a critical regulator of vascular contractility both at rest and as a functional endpoint for a number of endogenous vasodilators. Despite its key role, nothing is known about the processes that determine Kv7.4 channel activity. We reveal an interaction between G-protein βγ subunits and Kv7.4 that is crucial for channel responses to membrane voltage. Blocking this interaction ablates channel activity, prevents β-adrenoceptor–mediated relaxation, and constricts renal arteries. Conversely, Gβγ subunits enhance Kv7.4 channels and produce arterial relaxation in a Kv7-dependent manner. This reveals a fundamental reliance of an ion channel on Gβγ subunits for basal activity, a previously unidentified finding, which has profound implications for vascular physiology and disease pathogenesis.
The membrane remodeling protein Pex11p activates the GTPase Dnm1p during peroxisomal fission
Authors: Williams Chris , Opalinski Lukasz , Landgraf Christiane , Costello Joseph , Schrader Michael , Krikken Arjen M. , Knoops Kèvin , Kram Anita M. , Volkmer Rudolf , van der Klei Ida J.
Published: May 2015

Significance

Peroxisomal fission is crucial for cell viability because peroxisome fission defects cause severe disease. The initial step in peroxisomal fission, membrane elongation, requires the membrane remodeling protein Peroxin 11 (Pex11p). Here, we identify an additional function for Pex11p, demonstrating that Pex11p also plays a crucial role in the final step of peroxisomal fission: membrane separation. We show that Pex11p functions as a GTPase activating protein (GAP) for Dynamin-related 1 (Dnm1p) and that this GAP activity is conserved from yeast to mammalians. This work identifies a previously unknown requirement for a GAP in dynamin-like protein function.
Signature properties of water: Their molecular electronic origins
Authors: Sokhan Vlad P. , Jones Andrew P. , Cipcigan Flaviu S. , Crain Jason , Martyna Glenn J.
Published: May 2015

Significance

Water is one of the most common substances yet it exhibits anomalous properties important for sustaining life. It has been an enduring challenge to understand how a molecule of such apparent simplicity can encode for complex and unusual behavior across a wide range of pressures and temperatures. We reveal that embedding a complete hierarchy of electronic responses within the molecule allows water’s phase behavior and signature properties to emerge naturally even within a simple model. The key result is a simple and accurate, prediction of liquid–gas phase equilibria from freezing to the critical point thus establishing a direct link between molecular and condensed phase properties and a sound physical basis for a conceptually simple but broadly transferable model for water.
Metabolic dependencies drive species co-occurrence in diverse microbial communities
Authors: Zelezniak Aleksej , Andrejev Sergej , Ponomarova Olga , Mende Daniel R. , Bork Peer , Patil Kiran Raosaheb
Published: May 2015

Significance

Although metabolic interactions have long been implicated in the assembly of microbial communities, their general prevalence has remained largely unknown. In this study, we systematically survey, by using a metabolic modeling approach, the extent of resource competition and metabolic cross-feeding in over 800 microbial communities from diverse habitats. We show that interspecies metabolic exchanges are widespread in natural communities, and that such exchanges can provide group advantage under nutrient-poor conditions. Our results highlight metabolic dependencies as a major driver of species co-occurrence. The presented methodology and mechanistic insights have broad implications for understanding compositional variation in natural communities as well as for facilitating the design of synthetic microbial communities.
Persistent ecological shifts in marine molluscan assemblages across the end-Cretaceous mass extinction
Authors: Aberhan Martin , Kiessling Wolfgang
Published: May 2015

Significance

Global change and regime shifts of ecosystems are a major concern today. It has been suggested that the end-Cretaceous impact of an asteroid not only caused mass extinction but also involved the transgression of a global tipping point. We demonstrate that the ecological structure of pre- and postextinction assemblages of marine bivalves and gastropods differ far more than expected from usual background fluctuations. In-depth ecological analyses suggest site-specific rather than globally uniform shifts to different dynamic regimes. At more inclusive ecological levels, parallel increases emerge in mobility levels, in species burrowing into the sediment, and in deposit feeders and carnivores.
Place recognition and heading retrieval are mediated by dissociable cognitive systems in mice
Authors: Julian Joshua B. , Keinath Alexander T. , Muzzio Isabel A. , Epstein Russell A.
Published: May 2015

Significance

The ability to recover one’s bearings when lost is critical for successful navigation. To accomplish this feat, a navigator must identify its current location (place recognition), and it must also recover its facing direction (heading retrieval). Using a novel behavioral paradigm, we demonstrate that mice use one set of cues to determine their location and then ignore these same cues when determining their heading, although the cues are informative in both cases. These results suggest that place recognition and heading retrieval are mediated by different processing systems that operate in partial independence of each other. This finding has important implications for understanding the cognitive architecture underlying spatial navigation.
Discovery of a glowing millipede in California and the gradual evolution of bioluminescence in Diplopoda
Authors: Marek Paul E. , Moore Wendy
Published: May 2015

Significance

The enigmatic millipedeXystocheir bistipitahas been rediscovered after a half-century. The rediscovery unexpectedly reveals that the species is bioluminescent. By reconstructing its evolutionary history, we show thatX. bistipitais the evolutionary sister ofMotyxia, the only bioluminescent millipede genus in the order Polydesmida. We demonstrate that bioluminescence originated in the group’s common ancestor and incrementally grew brighter through evolutionary time. Luminescence inMotyxiamay have initially evolved to cope with metabolic stress triggered by a hot, dry environment and was repurposed as a warning signal by species colonizing high-elevation habitats with greater predation risk. The discovery of bioluminescence inX. bistipitaand its pivotal evolutionary location provides insight into repeated evolution of bioluminescence across the tree of life.
High-performance parallel image reconstruction for the New Vacuum Solar Telescope
Authors: Li Xue-Bao , Liu Zhong , Wang Feng , Jin Zhen-Yu , Xiang Yong-Yuan , Zheng Yan-Fang
Published: May 2015

Many technologies have been developed to help improve spatial resolution of observational images for ground-based solar telescopes, such as adaptive optics (AO) systems and post-processing reconstruction. As any AO system correction is only partial, it is indispensable to use post-processing reconstruction techniques. In the New Vacuum Solar Telescope (NVST), a speckle-masking method is used to achieve the diffraction-limited resolution of the telescope. Although the method is very promising, the computation is quite intensive, and the amount of data is tremendous, requiring several months to reconstruct observational data of one day on a high-end computer. To accelerate image reconstruction, we parallelize the program package on a high-performance cluster. We describe parallel implementation details for several reconstruction procedures. The code is written in the C language using the Message Passing Interface (MPI) and is optimized for parallel processing in a multiprocessor environment. We show the excellent performance of parallel implementation, and the whole data processing speed is about 71 times faster than before. Finally, we analyze the scalability of the code to find possible bottlenecks, and propose several ways to further improve the parallel performance. We conclude that the presented program is capable of executing reconstruction applications in real-time at NVST.
The ν2GC simulations: Quantifying the dark side of the universe in the Planck cosmology
Authors: Ishiyama Tomoaki , Enoki Motohiro , Kobayashi Masakazu A. R. , Makiya Ryu , Nagashima Masahiro , Oogi Taira
Published: May 2015

We present the evolution of dark matter halos in six large cosmological N-body simulations, called the ν2GC (New Numerical Galaxy Catalog) simulations on the basis of the ΛCDM cosmology consistent with observational results obtained with the Planck satellite. The largest simulation consists of 81923 (550 billion) dark matter particles in a box of 1.12 h−1 Gpc (a mass resolution of 2.20 × 108 h−1 M⊙). Among simulations utilizing boxes larger than 1 h−1 Gpc, our simulation yields the highest resolution simulation that has ever been achieved. A ν2GC simulation with the smallest box consists of eight billion particles in a box of 70 h−1 Mpc (a mass resolution of 3.44 × 106 h−1 M⊙). These simulations can follow the evolution of halos over masses of eight orders of magnitude, from small dwarf galaxies to massive clusters. Using the unprecedentedly high resolution and powerful statistics of the ν2GC simulations, we provide statistical results of the halo mass function, mass accretion rate, formation redshift, and merger statistics, and present accurate-fitting functions for the Planck cosmology. By combining the ν2GC simulations with our new semianalytic galaxy formation model, we are able to prepare mock catalogs of galaxies and active galactic nuclei, which will be publicly available in the near future.
Genetic Polymorphisms in Autophagy‐Associated Genes in Korean Children With Early‐Onset Crohn Disease
Authors: Na So Young , Park Sung Sup , Seo Jeong Kee
Published: May 2015

Objective:

The aim of the present study was to investigate the genetic polymorphisms of the autophagy‐associated genes autophagy‐related 16‐like 1 (ATG16L1), immunity‐related GTPase M (IRGM), Unc‐51‐like kinase 1 (ULK1), and NOD2 with respect to early‐onset Crohn disease (CD) among Korean children.

Methods:

A total of 65 patients with CD from the Seoul National University Children's Hospital, from January 2000 to May 2012, and 72 unaffected controls were selected. Twelve different single nucleotide polymorphisms (SNPs) were analyzed (TaqMan assay: ATG16L1 rs2241880, IRGM SNPs [rs13361189, rs4958847, rs1000113, rs10065172, and rs72553867], ULK1 SNPs [rs12303764, rs10902469, and rs7488085], NOD2 SNPs [Arg702Trp and Gly908Arg]; direct sequencing: NOD2 leu1007fsinsC). The onset age of patients was 8.6 ± 4.7 years. Twelve patients (18.5%) had an onset age of <1 year.

Results:

Two of the 12 SNPs showed significant results. IRGM rs1000113 exhibited an association with CD with respect to its minor allele frequency (odds ratio [OR] 1.71, 95% confidence interval [CI] 1.05–2.79, P = 0.03) and genotype distribution (dominant model: OR 2.17, 95% CI 1.07–4.39, P = 0.03). IRGM rs72553867 exhibited association with CD with respect to its minor allele frequency (OR 0.50, 95% CI 0.27–0.91, P = 0.02) and genotype distribution (dominant model: OR 0.50, 95% CI 0.23–0.94, P = 0.03). The 3 SNPs of NOD2 existed only as wild types for both groups. In the genotype‐phenotype analysis, the onset age, disease location, and disease behavior exhibited no association.

Conclusions:

IRGM rs1000113 and IRGM rs72553867 exhibited associations with early‐onset CD as risk loci and defense loci, respectively. This suggests that the autophagy pathway plays an important role in early‐onset CD.
A novel SOD1-dependent mechanism for the iron-induced production of toxic SOD1 and oxidative stress that initiates ALS
Authors: Lim Liangzhong , Song Jianxing
Published: May 2015

Free iron is highly toxic and the blood-derived iron initiates early motor-neuron degeneration upon breakdown of blood-spinal cord barrier. Iron is currently known to trigger oxidative stress by Fenton chemistry but no report implies that iron manifests its toxicity through CuZn-superoxide dismutase (SOD1), the central antioxidant enzyme in all human tissues that carries >180 ALS-causing mutations. Here, by NMR we show that Zn2+play an irreplaceable role in the maturation of the nascent hSOD1, and further decipher for the first time that out of 11 other cations only Fe2+has the Zn2+-like capacity to induce folding to form the Fe2+-bound hSOD1. This acts to reduce or even block the maturation of wild-type and ALS-causing mutant hSOD1, consequently trapping SOD1 in toxic forms and provoking oxidative stress. Our study establishes a novel SOD1-dependent mechanism for iron to manifest cellular toxicity that contributes to pathogenesis of neurodegenerative diseases, aging and even more.

One Sentence Summary

Our study establishes a novel SOD1-dependent mechanism for iron to manifest toxicity contributing to neurodegenerative diseases, aging and even more.
Using the Phenoscape Knowledgebase to relate genetic perturbations to phenotypic evolution
Authors: Manda Prashanti , Balhoff James P. , Lapp Hilmar , Mabee Paula , Vision Todd J.
Published: May 2015

The abundance of phenotypic diversity among species can enrich our knowledge of development and genetics beyond the limits of variation that can be observed in model organisms. The Phenoscape Knowledgebase (KB) is designed to enable exploration and discovery of phenotypic variation among species. Because phenotypes in the KB are annotated using standard ontologies, evolutionary phenotypes can be compared with phenotypes from genetic perturbations in model organisms. To illustrate the power of this approach, we review the use of the KB to find taxa showing evolutionary variation similar to that of a query gene. Matches are made between the full set of phenotypes described for a gene and an evolutionary profile, the latter of which is defined as the set of phenotypes that are variable among the daughters of any node on the taxonomic tree. Phenoscape’s semantic similarity interface allows the user to assess the statistical significance of each match and flags matches that may only result from differences in annotation coverage between genetic and evolutionary studies. Tools such as this will help meet the challenge of relating the growing volume of genetic knowledge in model organisms to the diversity of phenotypes in nature. The Phenoscape KB is available athttp://kb.phenoscape.org.