bluuebunny/crossref_metadata_2025 huggingface dataset:
Template-directed ligation on repetitive DNA sequences: a chemical method to probe the length of Huntington DNA
Authors: Kern Anika , Seitz Oliver
Published: September 2014

Several genomic disorders are caused by an excessive number of DNA triplet repeats.
The effect of soft nanoparticles morphologies on thin film composite membrane performance
Authors: Fu Qiang , Wong Edgar H. H. , Kim Jinguk , Scofield Joel M. P. , Gurr Paul A. , Kentish Sandra E. , Qiao Greg G.
Published: September 2014

Novel soft nanoparticles with tunable morphologies were incorporated into thin film composite membrane system for efficient CO2 capture applications.
A conjugated porous poly-benzobisthiadiazole network for a visible light-driven photoredox reaction
Authors: Wang Zi Jun , Ghasimi Saman , Landfester Katharina , Zhang Kai A. I.
Published: September 2014

A conjugated porous poly-benzobisthiadiazole network was synthesized via high internal phase emulsion polymerization as a highly active and stable heterogeneous photocatalyst.
Adsorption performance of functionalized chitosan–silica hybrid materials toward rare earths
Authors: Roosen Joris , Spooren Jeroen , Binnemans Koen
Published: September 2014

Functionalized chitosan–silica hybrid materials were synthesized, characterized and used for adsorption of rare-earth ions. These adsorbents can be used for the separation of mixtures of rare-earths.
Log‐Euclidean bag of words for human action recognition
Authors: Faraki Masoud , Palhang Maziar , Sanderson Conrad
Published: September 2014

Representing videos by densely extracted local space–time features has recently become a popular approach for analysing actions. In this study, the authors tackle the problem of categorising human actions by devising bag of words (BoWs) models based on covariance matrices of spatiotemporal features, with the features formed from histograms of optical flow. Since covariance matrices form a special type of Riemannian manifold, the space of symmetric positive definite (SPD) matrices, non‐Euclidean geometry should be taken into account while discriminating between covariance matrices. To this end, the authors propose to embed SPD manifolds to Euclidean spaces via a diffeomorphism and extend the BoW approach to its Riemannian version. The proposed BoW approach takes into account the manifold geometry of SPD matrices during the generation of the codebook and histograms. Experiments on challenging human action datasets show that the proposed method obtains notable improvements in discrimination accuracy, in comparison with several state‐of‐the‐art methods.
Quasi‐steady‐state large‐signal modelling of DC–DC switching converter: justification and application for varying operating conditions
Authors: Zhou Luowei , Liu Sucheng , Lu Weiguo , Hu Shuchang
Published: September 2014

Quasi‐steady‐state (QSS) large‐signal models are often taken for granted in the analysis and design of DC–DC switching converters, particularly for varying operating conditions. In this study, the premise for the QSS is justified quantitatively for the first time. Based on the QSS, the DC–DC switching converter under varying operating conditions is reduced to the linear time varying systems model. Thereafter, the QSS concept is applied to analysis of frequency‐domain properties of the DC–DC switching converters by using three‐dimensional Bode plots, which is then utilised to the optimisation of the controller parameters for wide variations of input voltage and load resistance. An experimental prototype of an average‐current‐mode‐controlled boost DC–DC converter is built to verify the analysis and design by both frequency‐domain and time‐domain measurements.
Novel carrier‐based hybrid pulse width modulation method for cascaded capacitor‐clamp multilevel inverter
Authors: Kim Ki‐Mok , Choi Won‐Shik , Park Ki‐Hyeon
Published: September 2014

This study presents a new carrier‐based hybrid pulse width modulation (PWM) Method for the cascaded capacitor‐clamp multilevel inverter (CCCMLI), which combines the benefits of a new alternative level‐shifted carrier PWM and a phase‐shifted carrier PWM. For modulating the CCCMLI, the phase disposition sub‐harmonic PWM was first proposed, but does not show good performances in an even load sharing between inverter cells connected in series, flying‐capacitor voltage balancing and output waveform quality. On the other hand, a proposed PWM method enables to achieve a balanced load sharing between cascaded cells even at low amplitude modulation indices as well as the excellent voltage balancing control of the flying‐capacitors with a much smaller voltage ripple and the good harmonic characteristics in output waveforms. The proposed modulation is verified through both simulation and field‐programmable gate array (FPGA) based experimental results.
Topological defects around a spherical nanoparticle in nematic liquid crystal: Coarse-grained molecular dynamics simulations
Authors: Ilnytskyi Jaroslav M. , Trokhymchuk Andrij , Schoen Martin
Published: September 2014

We consider the applicability of coarse-grained molecular dynamics for the simulation of defects in a nematic liquid crystal around a colloidal particle. Two types of colloids are considered, a soft colloid resembling a liquid crystal dendrimer or a similar macromolecule. In addition, a decorated colloid is used which could represent a gold nanoparticle with mesogen-modified surface. For both models we consider homeotropic and tangential anchoring. Precise control of the easy axis on the colloid's surface enables us to focus on specific planar arrangements in the case of a decorated colloid. The nematic phase is modelled explicitly via soft spherocylinders interacting through a potential, suggested by Lintuvuori and Wilson [J. Chem. Phys. 128, 044906 (2008)]. Properties of the nematic phase are studied by computing the Frank elastic constants. In addition, estimates for the nematic-isotropic transition and the coherence length allow us to establish a relation between energy and length scales with respect to experimental systems. Both models exhibit similar defect topologies, namely, that of a Saturn ring and a boojum-type of defect for homeotropic and tangential surface anchoring, respectively. In the decorated colloid model we tune the anchoring strength through the density of the mesogenic shell on the surface. We also found the biaxial boojum defect for the special case of longitudinal planar anchoring. The study demonstrates the potential of coarse-grained simulation methods for studying defects in liquid crystals.
Scattering and leapfrogging of vortex rings in a superfluid
Authors: Caplan R. M. , Talley J. D. , Carretero-González R. , Kevrekidis P. G.
Published: September 2014

The dynamics of vortex ring pairs in the homogeneous nonlinear Schrödinger equation is studied. The generation of numerically exact solutions of traveling vortex rings is described and their translational velocity compared to revised analytic approximations. The scattering behavior of co-axial vortex rings with opposite charge undergoing collision is numerically investigated for different scattering angles yielding a surprisingly simple result for its dependence as a function of the initial vortex ring parameters. We also study the leapfrogging behavior of co-axial rings with equal charge and compare it with the dynamics stemming from a modified version of the reduced equations of motion from a classical fluid model derived using the Biot-Savart law.
Mixing in thermally stratified nonlinear spin-up with uniform boundary fluxes
Authors: Baghdasarian Meline , Pacheco-Vega Arturo , Pacheco J. Rafael , Verzicco Roberto
Published: September 2014

Studies of stratified spin-up experiments in enclosed cylinders have reported the presence of small pockets of well-mixed fluids but quantitative measurements of the mixedness of the fluid has been lacking. Previous numerical simulations have not addressed these measurements. Here we present numerical simulations that explain how the combined effect of spin-up and thermal boundary conditions enhances or hinders mixing of a fluid in a cylinder. The energy of the system is characterized by splitting the potential energy into diabatic and adiabatic components, and measurements of efficiency of mixing are based on both, the ratio of dissipation of available potential energy to forcing and variance of temperature. The numerical simulations of the Navier–Stokes equations for the problem with different sets of thermal boundary conditions at the horizontal walls helped shed some light on the physical mechanisms of mixing, for which a clear explanation was absent.
Stimulated scattering in laser driven fusion and high energy density physics experiments
Authors: Yin L. , Albright B. J. , Rose H. A. , Montgomery D. S. , Kline J. L. , Kirkwood R. K. , Milovich J. , Finnegan S. M. , Bergen B. , Bowers K. J.
Published: September 2014

In laser driven fusion and high energy density physics experiments, one often encounters a kλD range of 0.15 < kλD < 0.5, where stimulated Raman scattering (SRS) is active (k is the initial electron plasma wave number and λD is the Debye length). Using particle-in-cell simulations, the SRS reflectivity is found to scale as ∼ (kλD)−4 for kλD ≳ 0.3 where electron trapping effects dominate SRS saturation; the reflectivity scaling deviates from the above for kλD < 0.3 when Langmuir decay instability (LDI) is present. The SRS risk is shown to be highest for kλD between 0.2 and 0.3. SRS re-scattering processes are found to be unimportant under conditions relevant to ignition experiments at the National Ignition Facility (NIF). Large-scale simulations of the hohlraum plasma show that the SRS wavelength spectrum peaks below 600 nm, consistent with most measured NIF spectra, and that nonlinear trapping in the presence of plasma gradients determines the SRS spectral peak. Collisional effects on SRS, stimulated Brillouin scattering (SBS), LDI, and re-scatter, together with three dimensional effects, are examined. Effects of collisions are found to include de-trapping as well as cross-speckle electron temperature variation from collisional heating, the latter of which reduces gain, introduces a positive frequency shift that counters the trapping-induced negative frequency shift, and affects SRS and SBS saturation. Bowing and breakup of ion-acoustic wavefronts saturate SBS and cause a dramatic, sharp decrease in SBS reflectivity. Mitigation of SRS and SBS in the strongly nonlinear trapping regime is discussed.
Narrow band photocurrent response from partially phase separated a-SiNx:H thin films
Authors: Bommali R. K. , Ahmad Shahab , Sharma Nandlal , Srivastava P. , Vijaya Prakash G.
Published: September 2014

We report static and dynamic photocurrent response from sub-stoichiometric a-SiNx:H thin films. The photocurrent spectral (PCS) response is peaked in the technologically important optical energy range of 2.2 to 4.5 eV. The transient photocurrent response with prolonged exposure is attributed to reduction in number of charge carriers due to trapping of photo-generated carriers at defect sites. The narrow PCS response is attributed to dominant photo-generation of carriers in the bandtails of stoichiometric Si3N4 phase and subsequent transport through the excess Si network.
In-situ observation of self-regulated switching behavior in WO3-x based resistive switching devices
Authors: Hong D. S. , Wang W. X. , Chen Y. S. , Sun J. R. , Shen B. G.
Published: September 2014

The transmittance of tungsten oxides can be adjusted by oxygen vacancy (Vo) concentration due to its electrochromic property. Here, we report an in-situ observation of resistive switching phenomenon in the oxygen-deficient WO3-x planar devices. Besides directly identifying the formation/rupture of dark-colored conductive filaments in oxide layer, the stripe-like WO3-x device demonstrated self-regulated switching behavior during the endurance testing, resulting in highly consistent switching parameters after a stabilizing process. For very high Vos mobility was demonstrated in the WO3-x film by the pulse experiment, we suggested that the electric-field-induced homogeneous migration of Vos was the physical origin for such unique switching characteristics.
Unexpected ferromagnetic ordering enhancement with crystallite size growth observed in La0.5Ca0.5MnO3 nanoparticles
Authors: Iniama G. , de la Presa P. , Alonso J. M. , Multigner M. , Ita B. I. , Cortés-Gil R. , Ruiz-González M. L. , Hernando A. , Gonzalez-Calbet J. M.
Published: September 2014

In this paper, the physical properties of half-doped manganite La0.5Ca0.5MnO3 with crystallite sizes ranging from 15 to 40 nm are investigated. As expected, ferromagnetic order strengthens at expense of antiferromagnetic one as crystallite size is reduced to 15 nm. However, contrary to previously reported works, an enhancement of saturation magnetization is observed as crystallite size increases from 15 to 22 nm. This unexpected behavior is accompanied by an unusual cell volume variation that seems to induce ferromagnetic-like behavior at expense of antiferromagnetic one. Besides, field cooled hysteresis loops show exchange bias field and coercivity enhancement for increasing cooling fields, which suggest a kind of core-shell structure with AFM-FM coupling for crystallite sizes as small as 15 nm. It is expected that inner core orders antiferromagnetically, whereas uncompensated surface spins behave as spin glass with ferromagnetic-like ordering.
Dependence of dynamic magnetization and magneto-transport properties of FeAlSi films with oblique sputtering studied via spin rectification effect
Authors: Soh Wee Tee , Zhong Xiaoxi , Ong C. K.
Published: September 2014

FeAlSi (Sendust) is known to possess excellent soft magnetic properties comparable to traditional soft magnetic alloys such as NiFe (Permalloy), while having a relatively higher resistance for lower eddy current losses. However, their dynamic magnetic and magneto-transport properties are not well-studied. Via the spin rectification effect, we electrically characterize a series of obliquely sputtered FeAlSi films at ferromagnetic resonance. The variations of the anisotropy fields and damping with oblique angle are extracted and discussed. In particular, two-magnon scattering is found to dominate the damping behavior at high oblique angles. An analysis of the results shows large anomalous Hall effect and anisotropic magneto-resistance across all samples, which decreases sharply with increasing oblique incidence.
Dynamic resistance of a high-Tc superconducting flux pump
Authors: Jiang Zhenan , Hamilton K. , Amemiya Naoyuki , Badcock R. A. , Bumby C. W.
Published: September 2014

Superconducting flux pumps enable large currents to be injected into a superconducting circuit, without the requirement for thermally conducting current leads which bridge between the cryogenic environment and room temperature. In this work, we have built and studied a mechanically rotating flux pump which employs a coated conductor high-Tc superconducting (HTS) stator. This flux pump has been used to excite an HTS double pancake coil at 77 K. Operation of the flux pump causes the current within the superconducting circuit to increase over time, before saturating at a limiting value. Interestingly, the superconducting flux pump is found to possess an effective internal resistance, Reff, which varies linearly with frequency, and is two orders of magnitude larger than the measured series resistance of the soldered contacts within the circuit. This internal resistance sets a limit for the maximum achievable output current from the flux pump, which is independent of the operating frequency. We attribute this effect to dynamic resistance within the superconducting stator wire which is caused by the interaction between the DC transport current and the imposed alternating magnetic field. We provide an analytical expression describing the output characteristics of our rotating flux pump in the high frequency limit, and demonstrate that it describes the time-dependent behavior of our experimental circuit. Dynamic resistance is highlighted as a generic issue that must be considered when optimizing the design of an HTS flux pump.
Experimental assessment of anomalous low-frequency noise increase at the onset of Gunn oscillations in InGaAs planar diodes
Authors: García-Pérez Ó. , Alimi Y. , Song A. , Íñiguez-de-la-Torre I. , Pérez S. , Mateos J. , González T.
Published: September 2014

In this work, the presence of anomalous low-frequency fluctuations during the initiation of higher frequency oscillations in InGaAs-based Gunn planar diodes has been evidenced and investigated. Accurate measurements showing the evolution of the power spectral density of the device with respect to the applied voltage have been carried out. Such spectra have been obtained in the wide frequency range between 10 MHz and 43.5 GHz, simultaneously covering both the low-frequency noise and the fundamental oscillation peak at some tens of GHz. This provides valuable information to better understand how these fluctuations appear and how these are distributed in frequency. For much higher frequency operation, such understanding can be utilized as a simple tool to predict the presence of Gunn oscillations without requiring a direct detection.
Urban Water Governance Failure and Local Strategies for Overcoming Water Shortages in Dar es Salaam, Tanzania
Authors: Rugemalila Richard , Gibbs Leah
Published: September 2014

In Tanzania's largest city, Dar es Salaam, water supply does not meet the needs of the community. In response, people adopt multiple strategies to secure adequate water for their daily requirements. This paper investigates urban water provision and governance in Dar es Salaam, and has two aims: to investigate the causes of urban water failure; and to examine the full range of strategies employed by the local community to overcome water shortages. We critique the socioeconomic implications of both water shortages themselves and the methods used to overcome them. The paper draws on a household survey and key informant interviews in Temeke, one of the city's three municipalities. We find that failing urban infrastructure and rapid urbanisation place additional pressure on water supply, but argue that the primary cause of water shortages is water governance failure.
Water use efficiency in Sangiovese grapes (Vitis vinifera L.) subjected to water stress before veraison: different levels of assessment lead to different conclusions
Authors: Merli Maria Clara , Gatti Matteo , Galbignani Marco , Bernizzoni Fabio , Magnanini Eugenio , Poni Stefano
Published: September 2014

Several recent papers have shown that in grapevine (Vitis vinifera L.), interpretation of responses to drought can differ depending upon the parameter chosen to express water use efficiency (WUE). In the present paper, a series of WUE expressions, including physiological and agronomical, were compared in potted grapevines (Vitis vinifera L. cv. Sangiovese) that were either well-watered (WW) or subjected to progressive drought before veraison (WS) by supplying decreasing fractions (i.e. 70%, 50% and 30% of daily vine transpiration (Trd) determined gravimetrically before vines were fully rewatered. Although single-leaf intrinsic and instantaneous WUE increased with water stress severity, seasonal and whole-canopy WUE were similar to that before stress, at 70% Trd and upon rewatering, but dropped during severe water stress. WUE calculated as mass of DW stored in annual biomass (leaves, canes and bunches) per litre of water used did not differ on a seasonal basis, whereas WS plants showed lower must soluble solids at harvest, and unchanged colour and phenolic concentration in spite of smaller berries with higher relative skin growth. Results confirm that whole-canopy WUE is a much better index than any single-leaf based WUE parameter for extrapolation to agronomic WUE and actual grape composition. In our specific case study, it can be recommended that water supply to drought-stressed Sangiovese grapevines before veraison should not be lower than 70% of daily vine water use.
Linking plant and ecosystem functional biogeography
Authors: Reichstein Markus , Bahn Michael , Mahecha Miguel D. , Kattge Jens , Baldocchi Dennis D.
Published: September 2014

Significance

This article defines ecosystem functional properties, which can be derived from long-term observations of gas and energy exchange between ecosystems and the atmosphere, and shows that variations of those cannot be easily explained by classical climatological or biogeographical approaches such as plant functional types. Instead, we argue that plant traits have the potential to explain this variation, and we call for a stronger integration of research communities dedicated to plant traits and to ecosystem–atmosphere exchange.
Team science for science communication
Authors: Wong-Parodi Gabrielle , Strauss Benjamin H.
Published: September 2014

Natural scientists from Climate Central and social scientists from Carnegie Mellon University collaborated to develop science communications aimed at presenting personalized coastal flood risk information to the public. We encountered four main challenges: agreeing on goals; balancing complexity and simplicity; relying on data, not intuition; and negotiating external pressures. Each challenge demanded its own approach. We navigated agreement on goals through intensive internal communication early on in the project. We balanced complexity and simplicity through evaluation of communication materials for user understanding and scientific content. Early user test results that overturned some of our intuitions strengthened our commitment to testing communication elements whenever possible. Finally, we did our best to negotiate external pressures through regular internal communication and willingness to compromise.
Using narratives and storytelling to communicate science with nonexpert audiences
Authors: Dahlstrom Michael F.
Published: September 2014

Although storytelling often has negative connotations within science, narrative formats of communication should not be disregarded when communicating science to nonexpert audiences. Narratives offer increased comprehension, interest, and engagement. Nonexperts get most of their science information from mass media content, which is itself already biased toward narrative formats. Narratives are also intrinsically persuasive, which offers science communicators tactics for persuading otherwise resistant audiences, although such use also raises ethical considerations. Future intersections of narrative research with ongoing discussions in science communication are introduced.
Hominoid-specific enzyme GLUD2 promotes growth of
IDH1

R132H

glioma
Authors: Chen Ruihuan , Nishimura Merry C. , Kharbanda Samir , Peale Frank , Deng Yuzhong , Daemen Anneleen , Forrest William F. , Kwong Mandy , Hedehus Maj , Hatzivassiliou Georgia , Friedman Lori S. , Phillips Heidi S.
Published: September 2014

Significance

Mutation of isocitrate dehydrogenase 1 (
IDH1
) is believed to be the initiating event for the majority of secondary glioblastomas and lower-grade diffuse gliomas; however, the basis for tissue specificity of oncogenesis initiated by
IDH1
mutation has not been apparent. We report evidence to suggest that specialization of human neocortex for glutaminergic neurotransmission provides a metabolic niche particularly suited for growth of
IDH1

R132H

glioma. Our findings reveal that
IDH1
-mutant enzyme challenges growth of murine glioma progenitor cells but that these cells thrive if they are engineered to express the hominoid-specific brain enzyme GLUD2, a mitochondrial enzyme that converts glutamate to alpha-ketoglutarate in human cortex. The current findings raise the possibility that evolutionary changes contributing to human cognitive abilities may have conferred vulnerability to brain tumors driven by
IDH1
mutation.
Quantum critical fluctuations in layered YFe
2
Al
10
Authors: Wu L. S. , Kim M. S. , Park K. , Tsvelik A. M. , Aronson M. C.
Published: September 2014

Significance

Temperature-driven phase transitions, such as the melting of ice or the boiling of water, are a familiar part of daily life. Much less is known about the most extreme phase transitions, which happen only at zero temperature, where quantum fluctuations limit the stabilities of different collective ground states such as magnetic order and superconductivity. We report an experimental investigation of YFe
2
Al
10
, where planes of Fe atoms are naturally poised on the verge of ferromagnetic order, exactly at
T
= 0. The thermal, magnetic, and electrical transport properties in YFe
2
Al
10
all diverge as
T
→ 0, a process that can be reversed by magnetic fields in a way that is dictated by the underlying system energy.
Ten-percent solar-to-fuel conversion with nonprecious materials
Authors: Cox Casandra R. , Lee Jungwoo Z. , Nocera Daniel G. , Buonassisi Tonio
Published: September 2014

Significance

For solar water splitting to be an economically viable resource, a 10% or higher solar-to-fuel conversion efficiency is required. Silicon photovoltaics (PV) are particularly attractive because silicon absorbs most of the solar spectrum, is nonprecious, and PV devices have dropped in price dramatically within the last decade. We demonstrate that by coupling a buried-junction silicon PV module with water-splitting catalysts, a 10% solar-to-fuels efficiency is achieved using all nonprecious and technology-ready materials.
Both endo-siRNAs and tRNA-derived small RNAs are involved in the differentiation of primitive eukaryote
Giardia lamblia
Authors: Liao Jian-You , Guo Yan-Hua , Zheng Ling-Ling , Li Yan , Xu Wen-Li , Zhang Yu-Chan , Zhou Hui , Lun Zhao-Rong , Ayala Francisco J. , Qu Liang-Hu
Published: September 2014

Significance

Small RNAs (sRNAs) are most important regulators in eukaryotes. Although different kinds of sRNAs have been extensively studied in higher eukaryotes, their role remains largely unknown in protozoa. We have systematically investigated in the full genome the sRNAs of
Giardia lamblia
, the most primitive eukaryote known. Surprisingly, we have found that two major types of sRNAs (i.e., endogenous siRNAs and tRNA-derived sRNAs) are largely encoded in the genome of
G. lamblia
, whereas canonical microRNAs could not be identified in this parasite. Additional studies showed that both sRNAs might be involved in the differentiation regulation of
G. lamblia
. This study indicates that these two kinds of eukaryotic sRNAs emerged in the early evolution of eukaryotes.
Exact solution for a metapopulation version of Schelling’s model
Authors: Durrett Richard , Zhang Yuan
Published: September 2014

Significance

More than 40 y ago, Schelling introduced one of the first agent-based models in the social sciences. The model showed that even if people only have a mild preference for living with neighbors of the same color, complete segregation will occur. This model has been much discussed by social scientists and analyzed by physicists using analogies with spin-1 Ising models and other systems. Here, we study the metapopulation version of the model, which mimics the division of a city into neighborhoods, and we present the first analysis to our knowledge that gives detailed information about the structure of equilibria and explicit formulas for their densities.
Contesting Foreign Policy: Disagreement between the Ottoman Ministry of Foreign Affairs and the Ministry of War on the Shatt al-Arab Dispute with Iran, 1912–13
Authors: Kurt Burcu
Published: September 2014

The Shatt al-Arab question has been the subject of several studies, most of which concentrate on the internationalization of the subject. However, few, if any, works have analyzed how this territorial dispute was perceived within Ottoman bureaucratic circles. When the Ottoman Empire reinstated a constitutional monarchy in 1908, the Ottoman–Iranian border dispute regarding the Shatt al-Arab had to be readdressed, with international players involved in the process. Considering the role of foreign factors, this study focuses on the contesting interests of the Ottoman Ministry of Foreign Affairs and the Ministry of War on the Shatt al-Arab question (1912–13) and considers how these interests shaped foreign policy in the process of negotiating a resolution.
Lgr4 is required for endometrial receptivity acquired through ovarian hormone signaling
Authors: Kida Tomoyo , Oyama Kazunori , Sone Mizuki , Koizumi Masae , Hidema Shizu , Nishimori Katsuhiko
Published: September 2014

Previously, using the Keratin5-Cre transgenic mouse model we reported that female Lgr4-conditional KO mice (Lgr4K5 KO) showed subfertility with defective stromal decidualization due to abnormal development of the uterine gland. However, the impact of the LGR4 defect on luminal epithelial cells was not investigated in the previous report. Here, we focused on the receptive state of the luminal epithelium in Lgr4K5 KO mice that received ovarian hormone treatment. In Lgr4K5 KO mice, progesterone failed to inhibit the luminal epithelial cell proliferation. Immunohistochemical and qRT-PCR analyses revealed down-regulated progesterone signaling in the uterus of Lgr4K5 KO mice. These results demonstrated that LGR4 is essential for the acquisition of endometrial receptivity through ovarian hormone signaling.
The “Lessepsian invasion” – a case study revisited
Authors: Safriel Uriel N.
Published: September 2014

A case study of the Lessepsian invasion of the Mediterranean Sea was carried out during the 1970s by a Hebrew University of Jerusalem team that included Uzi Ritte and his research students. The study zoomed on two mollusk “trios” of mytilid bivalves and cerithiid gastropods, each including an invader, a closely related and ecologically similar indigenous Red Sea species and a Mediterranean indigenous competitor. This paper revisits the results, conclusions and projections made by the 1970s study in the context of a recent unified invasion biology framework, and in the view of the dynamic development of the Lessepsian invasion and research into it throughout the more than 30 years since the case study took place. The approach of studying “trios” to detect potential invaders and project the course of invasions has not been repeated in the Lessepsian system since the 1970s case study. But the findings that opportunistic life history traits linked with a match of habitat in the invaded range to a species’ ecological niche make this species a potential invader and enable it to coexist with an encountered competitor remain robust. Recent human-induced and other environmental changes in the Mediterranean have however highlighted a potential significance of propagule pressure in intensifying competitive exclusion and resource monopolization by the invader, to the point of potentially impacting the invaded ecosystem.
The effect of blocking inter-trial interval on sequential effects in absolute identification
Authors: Donkin Chris , Chan Vivian , Tran Sophia
Published: September 2014

Sequential effects are ubiquitous in decision-making, but no more than in the absolute identification task where participants must identify stimuli from a set of items that vary on a single dimension. A number of competing explanations for these sequential effects have been proposed, and recently Matthews and Stewart [(2009a). The effect of inter-stimulus interval on sequential effects in absolute identification. The Quarterly Journal of Experimental Psychology, 62, 2014–2029] showed that manipulations of the time between decisions is useful in discriminating between these accounts. We use a Bayesian hierarchical regression model to show that inter-trial interval has an influence on behaviour when it varies across different blocks of trials, but not when it varies from trial to trial. We discuss the implications of both our and Matthews and Stewart's results on the effect of inter-trial interval for theories of sequential effects.
Inter-hemispheric dynamics revealed by reaction time in the Dimond paradigm
Authors: Leblanc-Sirois Yanick , Braun Claude M. J.
Published: September 2014

The Dimond paradigm (DP) consists of tachistoscopically presenting two stimuli to be discriminated—either both stimuli in a single visual hemifield or one in each. The DP has recently been implemented using predecessors to index homotopy of the callosal fibre projection with reaction time (RT) as the dependent measure. Using simple perceptual discrimination tasks, it has recently been reported that the advantage of the unilateral stimulation condition significantly decreases with practice. This effect has been interpreted as being due to the plasticity of the callosal network. Two experiments were designed to replicate these two little-known effects, namely callosal homotopy and callosal network plasticity. In addition, new evidence of another type of callosal network plasticity, termed “callosal network dispatching”, was sought by introducing double manipulation of orientations of both stimulus-contours and inter-stimulus arrays to the DP. Strong support for the callosal homotopy and callosal network plasticity effects was obtained. In addition, evidence for a “callosal network dispatcher” effect accrued.
Relative prediction error and protection from attentional blink in human associative learning
Authors: Glautier Steven , Shih Shui-l
Published: September 2014

The relationship between predictive learning and attentional processing was investigated in two experiments. During a learning procedure participants viewed rapid serial visual presentation (RSVP) of stimuli in the context of a choice-reaction-time (CRT) task. Salient stimuli in the RSVP streams were either predictive or non-predictive for the outcome of the CRT task. Following this procedure we measured attentional blink (AB) to the predictive and non-predictive stimuli. In Experiment 1, despite the use of a large sample and checks demonstrating the validity of the learning procedure and the AB measure, we did not observe reduced AB for predictive stimuli. In contrast, in Experiment 2, where the predictive stimuli occurred alongside salient non-predictive comparison stimuli, we did find less AB for predictive than for non-predictive stimuli. Our results support an attentional model of learning in which relative prediction error is used to increase learning rates for good predictors and reduce learning rates for poor predictors and provide confirmation of the AB learning effect.
IKK-induced NF-κB1 p105 proteolysis is critical for B cell antibody responses to T cell–dependent antigen
Authors: Jacque Emilie , Schweighoffer Edina , Visekruna Alexander , Papoutsopoulou Stamatia , Janzen Julia , Zillwood Rachel , Tarlinton David M. , Tybulewicz Victor L.J. , Ley Steven C.
Published: September 2014

The importance of IκB kinase (IKK)–induced proteolysis of NF-κB1 p105 in B cells was investigated using Nfkb1SSAA/SSAA mice, in which this NF-κB signaling pathway is blocked. Nfkb1SSAA mutation had no effect on the development and homeostasis of follicular mature (FM) B cells. However, analysis of mixed bone marrow chimeras revealed that Nfkb1SSAA/SSAA FM B cells were completely unable to mediate T cell–dependent antibody responses. Nfkb1SSAA mutation decreased B cell antigen receptor (BCR) activation of NF-κB in FM B cells, which selectively blocked BCR stimulation of cell survival and antigen-induced differentiation into plasmablasts and germinal center B cells due to reduced expression of Bcl-2 family proteins and IRF4, respectively. In contrast, the antigen-presenting function of FM B cells and their BCR-induced migration to the follicle T cell zone border, as well as their growth and proliferation after BCR stimulation, were not affected. All of the inhibitory effects of Nfkb1SSAA mutation on B cell functions were rescued by normalizing NF-κB activation genetically. Our study identifies critical B cell-intrinsic functions for IKK-induced NF-κB1 p105 proteolysis in the antigen-induced survival and differentiation of FM B cells, which are essential for T-dependent antibody responses.
Where is the land of Opportunity? The Geography of Intergenerational Mobility in the United States *
Authors: Chetty Raj , Hendren Nathaniel , Kline Patrick , Saez Emmanuel
Published: September 2014

We use administrative records on the incomes of more than 40 million children and their parents to describe three features of intergenerational mobility in the United States. First, we characterize the joint distribution of parent and child income at the national level. The conditional expectation of child income given parent income is linear in percentile ranks. On average, a 10 percentile increase in parent income is associated with a 3.4 percentile increase in a child’s income. Second, intergenerational mobility varies substantially across areas within the United States. For example, the probability that a child reaches the top quintile of the national income distribution starting from a family in the bottom quintile is 4.4% in Charlotte but 12.9% in San Jose. Third, we explore the factors correlated with upward mobility. High mobility areas have (i) less residential segregation, (ii) less income inequality, (iii) better primary schools, (iv) greater social capital, and (v) greater family stability. Although our descriptive analysis does not identify the causal mechanisms that determine upward mobility, the publicly available statistics on intergenerational mobility developed here can facilitate research on such mechanisms.
Transcriptome Analysis of a Ustilago maydis ust1 Deletion Mutant Uncovers Involvement of Laccase and Polyketide Synthase Genes in Spore Development
Authors: Islamovic Emir , García-Pedrajas María D. , Chacko Nadia , Andrews David L. , Covert Sarah F. , Gold Scott E.
Published: September 2014

Ustilago maydis, causal agent of corn smut disease, is a dimorphic fungus alternating between a saprobic budding haploid and an obligate pathogenic filamentous dikaryon. Maize responds to U. maydis colonization by producing tumorous structures, and only within these does the fungus sporulate, producing melanized sexual teliospores. Previously we identified Ust1, an APSES (Asm1p, Phd1p, Sok2p, Efg1p, and StuAp) transcription factor, whose deletion led to filamentous haploid growth and the production of highly pigmented teliospore-like structures in culture. In this study, we analyzed the transcriptome of a ust1 deletion mutant and functionally characterized two highly upregulated genes with potential roles in melanin biosynthesis: um05361, encoding a putative laccase (lac1), and um06414, encoding a polyketide synthase (pks1). The Δlac1 mutant strains showed dramatically reduced virulence on maize seedlings and fewer, less-pigmented teliospores in adult plants. The Δpks1 mutant was unaffected in seedling virulence but adult plant tumors generated hyaline, nonmelanized teliospores. Thus, whereas pks1 appeared to be restricted to the synthesis of melanin, lac1 showed a broader role in virulence. In conclusion, the ust1 deletion mutant provided an in vitro model for sporulation in U. maydis, and functional analysis supports the efficacy of this in vitro mutant analysis for identification of genes involved in in planta teliosporogenesis.
First Report of Carnation vein mottle virus Infecting Dianthus amurensis in China
Authors: Li M. R. , Zhu J. , Gao J. , Li R. H. , Li F.
Published: September 2014

Dianthus amurensis, commonly known as Amur Pink, is a species of the genus Dianthus in the family Caryophyllaceae. This perennial Dianthus is also a Chinese medicinal herb. In August 2012, mosaic, leaf cupping, leaf distortion, reduction in leaf size, and flower-breaking symptoms were observed on some D. amurensis plants in a Chinese herb nursery in Changchun, Jilin Province, China. Disease incidences ranged from 40 to 50% in different plots. Symptoms on diseased D. amurensis were similar to those on the diseased D. caryophyllus, D. barbatus, and D. japonicus. The symptoms resembled to those caused by Carnation vein mottle virus (CVMoV), a member of genus Potyvirus in the family Potyviridae (3). CVMoV infects carnations (D. caryophyllus) worldwide and causes a serious disease. To investigate the presence of CVMoV, leaf samples were collected from three symptomatic plants and tested by dot-ELISA using universal potyvirus group monoclonal antibody (Agdia, Inc., Elkhart, IN). The antibody reacted with the diseased samples, supporting the presence of a potyvirus. To identify the potyvirus species, total nucleic acids were extracted from the diseased samples by a CTAB method (2) and used as template in RT-PCR with potyvirus universal primers Sprimer and M4T (1). An amplicon of the expected size (~1.7 kb) was obtained from all three diseased samples. The amplicons were cloned into pMD18-T vector (TaKaRa, Dalian, China) and sequenced. Sequences obtained from all three samples were identical and deposited in GenBank (Accession No. KJ605654). BLAST search showed that the nucleotide sequence shared 97 and 98% identity with a Japanese CVMoV isolate infecting D. japonicus (AB017630) (3) and a Korean CVMoV isolate (AY512554), respectively. The results confirmed the association of CVMoV with the disease on D. amurensis. To determine the pathogenicity of CVMoV to D. amurensis plants, purified CVMoV from the diseased plants were used to inoculate to healthy Dianthus spp. plants. Inoculated Dianthus spp. plants also showed the symptoms of mottle, leaf cupping, and leaf distortion, and CVMoV could be detected by RT-PCR from these plants. The result confirms that CVMoV is the causal agent of the disease. To our knowledge, this is the first report of CVMoV infection in D. amurensis. Since D. amurensis is economically important in China, proper virus management strategies for the cultivation of this crop should be adopted.

References: (1) J. Chen et al. Arch. Virol. 146:757, 2001. (2) R. Li et al. J. Virol. Methods 154:48, 2008. (3) T. Sasaya et al. J. Gen. Plant Pathol. 66:251, 2000.
Characterization of the Dual Subcellular Localization of Lilium LsGRP1, a Plant Class II Glycine-Rich Protein
Authors: Lin Chia-Hua , Chen Chao-Ying
Published: September 2014

The defense-related gene LsGRP1 exhibits an increased level of expression in Lilium spp. after being infected by Botrytis elliptica, the fungal pathogen of lily leaf blight. In this study, the expression profile of the LsGRP1 protein (a plant class II glycine-rich protein) was characterized biochemically and its subcellular localization in lily leaves was evaluated using immunohistochemistry, enhanced green fluorescent protein (EGFP) imaging, and protein extraction analysis. Using an LsGRP1-specific antibody, LsGRP1 was found to be most abundant in epidermal cells and phloem tissues. Leaves from lily plants at different growth stages demonstrated similar levels of 14- and 16-kDa LsGRP1 and a decreased amount of 23-kDa LsGRP1 at the senescence stage. LsGRP1-EGFP imaging and protein extraction assays revealed that 14-kDa LsGRP1 was located in the plasma membrane whereas 16- and 23-kDa LsGRP1 was weakly bound to the cell wall. The time course analyses of LsGRP1 expression in response to salicylic acid treatment or B. elliptica infection showed an increased accumulation of 14- and 23-kDa LsGRP1 over time. Because 23-kDa LsGRP1 could be detected by an ubiquitin antibody, conversion of 14-kDa to 23-kDa LsGRP1 via mono-ubiquitination was presumed, which is a phenomenon that has not been reported for a plant class II glycine-rich protein.
Screening Metagenomic Data for Viruses Using the E-Probe Diagnostic Nucleic Acid Assay
Authors: Stobbe A. H. , Schneider W. L. , Hoyt P. R. , Melcher U.
Published: September 2014

Next generation sequencing (NGS) is not used commonly in diagnostics, in part due to the large amount of time and computational power needed to identify the taxonomic origin of each sequence in a NGS data set. By using the unassembled NGS data sets as the target for searches, pathogen-specific sequences, termed e-probes, could be used as queries to enable detection of specific viruses or organisms in plant sample metagenomes. This method, designated e-probe diagnostic nucleic acid assay, first tested with mock sequence databases, was tested with NGS data sets generated from plants infected with a DNA (Bean golden yellow mosaic virus, BGYMV) or an RNA (Plum pox virus, PPV) virus. In addition, the ability to detect and differentiate among strains of a single virus species, PPV, was examined by using probe sets that were specific to strains. The use of probe sets for multiple viruses determined that one sample was dually infected with BGYMV and Bean golden mosaic virus.
Astroglial cradle in the life of the synapse
Authors: Verkhratsky Alexei , Nedergaard Maiken
Published: September 2014

Astroglial perisynaptic sheath covers the majority of synapses in the central nervous system. This glial coverage evolved as a part of the synaptic structure in which elements directly responsible for neurotransmission (exocytotic machinery and appropriate receptors) concentrate in neuronal membranes, whereas multiple molecules imperative for homeostatic maintenance of the synapse (transporters for neurotransmitters, ions, amino acids, etc.) are shifted to glial membranes that have substantially larger surface area. The astrocytic perisynaptic processes act as an ‘astroglial cradle’ essential for synaptogenesis, maturation, isolation and maintenance of synapses, representing the fundamental mechanism contributing to synaptic connectivity, synaptic plasticity and information processing in the nervous system.
Spatial properties of astrocyte gap junction coupling in the rat hippocampus
Authors: Anders Stefanie , Minge Daniel , Griemsmann Stephanie , Herde Michel K. , Steinhäuser Christian , Henneberger Christian
Published: September 2014

Gap junction coupling enables astrocytes to form large networks. Its strength determines how easily a signalling molecule diffuses through the network and how far a locally initiated signal can spread. Changes of coupling strength are well-documented during development and in response to various stimuli. Precise quantification of coupling is needed for studying such modifications and their functional consequences. We therefore explored spatial properties of astrocyte coupling in a model simulating dye loading of single astrocytes. Dye spread into the astrocyte network could be characterized by a coupling length constant and coupling anisotropy. In experiments, the fluorescent marker Alexa Fluor 594 was used to measure these parameters in CA1 and dentate gyrus of the rat hippocampus. Coupling did not differ between regions but showed a temperature-dependence, partially owing to changes of intracellular diffusivity, detected by measuring coupling length constants but not the more variable cell counts of dye-coupled astrocytes. We further found that coupling is anisotropic depending on distance to the pyramidal cell layer, which correlated with regional differences of astrocyte morphology. This demonstrates that applying these new analytical approaches provides useful quantitative information on gap junction coupling and its heterogeneity.
Organization, control and function of extrasynaptic NMDA receptors
Authors: Papouin Thomas , Oliet Stéphane H. R.
Published: September 2014

N
-methyl
d
-aspartate receptors (NMDARs) exist in different forms owing to multiple combinations of subunits that can assemble into a functional receptor. In addition, they are located not only at synapses but also at extrasynaptic sites. There has been intense speculation over the past decade about whether specific NMDAR subtypes and/or locations are responsible for inducing synaptic plasticity and excitotoxicity. Here, we review the latest findings on the organization, subunit composition and endogenous control of NMDARs at extrasynaptic sites and consider their putative functions. Because astrocytes are capable of controlling NMDARs through the release of gliotransmitters, we also discuss the role of the glial environment in regulating the activity of these receptors.