bluuebunny/crossref_metadata_2025 huggingface dataset:
Mixing in the Solar Tachocline
Authors: Brun Allan Sacha
Published: March 2016

We conduct numerical simulations of updated solar models including a physical treatment of the tachocline (Spiegel & Zahn 1992), the rotational transition layer localized at the base of the solar convection zone. We first describe what is the current understanding of this thin shear layer. We then show that we improve substantially the agreement between the models and the observed Sun by taking into account the macroscopic mixing occuring within this region.
The Role of the Central (Pulkovo) Observatory in Southern Hemisphere Star Observations
Authors: Abalakin V.K. , Arkharov A.A. , Gnedin Y.N. , Kanayev I.I. , Polojentsev D.D. , Potter H.I.
Published: March 2016

The Nicholas Central Astronomical Observatory in Pulkovo, near Saint-Petersburg, was inaugurated as Russia's principal astronomical institution on 19 (7) August 1839. Construction of the observatory had begun in 1834 following the edict of the Russian Emperor Nicholas I, who had invited as his adviser Professor Friedrich Georg Wilhelm Struve, the Director of the Dorpat Observatory. Emperor Nicholas I appointed Wilhelm Struve as the Director of the new observatory. With regard to funding, the emperor had given Struve a carte blanche to enable him to order from German telescope makers the best astrometric instruments designed according to Struve's own ideas. Hence Wilhelm Struve is to be considered as the co-founder of Pulkovo Observatory.
How Oxygen Affects the CMDs and Predicted Ages of Extreme Population II Stars
Authors: VandenBerg Don A. , Bell R.A.
Published: March 2016

Stellar evolutionary models for [Fe/H] = −2.27 have been constructed to examine how predicted C-M diagrams, age versus turnoff-luminosity relations, the luminosities of the red-giant “bump” and tip, and the Teff/color of a zero-age horizontal branch model of fixed mass are affected by varying the assumed abundance of oxygen (with and without enhancements in the other α-elements).
Dust in Evolving Galaxies
Authors: Andreani Paola
Published: March 2016

I will first review the observational evidence relating dust emission and the energy production in the far-IR/submm range. This latter contains crucial information on the global baryons transformation and the related stellar activity in the Universe. Present knowledge on this topic relies mainly on the far-IR local surveys of IRAS and ISO missions and on submm/mm surveys performed with SCUBA and MAMBO arrays. Further constraints are provided by the measurements of the Cosmic far-IR Background (CFIRB). Our scanty knowledge of galaxy formation and evolution is mainly caused by the difficulties of unveiling stellar activity at redshifts larger than 1 and at present we may only have detected massive objects in a transient hyper-luminous phase. We still lack an unbiased census of the much more numerous population of lower luminosity dusty objects. It will soon be possible to disclose the entire history of evolving dusty objects, and therefore of the stellar activity, selecting unbiased samples out of far-IR imaging and photometry in deep far-IR surveys.
Radio Halos in Merging Clusters
Authors: Giovannini Gabriele , Feretti Luigina
Published: March 2016

The number of known diffuse radio sources in clusters of galaxies (halos and relics) has grown in recent years, making it possible to derive statistical considerations on the physical conditions of these sources and on the properties of related clusters. We will discuss the percentage of clusters with a diffuse source and will show evidence that diffuse sources are associated with X-ray luminous clusters which have undergone recent merger processes.
Photometric Calibrations after HIPPARCOS or: The Fine Structure of the HR-Diagram Revealed
Authors: Grenon Michel
Published: March 2016

The Hipparcos parallaxes allow us to revisit photometric calibrations in terms of Mv and to evaluate the effects of the overall metallicity across the HR-diagram. For evolved stars the spread in mass remains the major and irreducible source of errors in the photometric Mv. If the relative locations of open cluster main-sequences are fully explained by the ∆Mv versus ∆[M/H] relation, the residual scatter in the lower main sequence appears due to additional parameters such as rotation or gravitational settling of the heavy elements. These cannot readily be studied by a purely photometric approach.
Some Aspects of Galactic Cosmic Ray Acceleration
Authors: Butt Yousaf Mahmood
Published: March 2016

I give a synopsis of two aspects of the Galactic Cosmic Ray (GCR) acceleration problem: the importance of the medium energy gamma-ray window, and several specific astrophysical sources which merit further investigation. NOTE: figures may be found in the on-line version only: astro-ph/0309758.
Ejection of Bi-Helical Fields from the Sun
Authors: Brandenburg Axel , Blackman Eric G.
Published: March 2016

It is argued that much of the observed magnetic helicity losses at the solar surface may represent a reduction of an otherwise more dominant nonlinearity of solar and stellar dynamos. This nonlinearity is proportional to the internal twist (as opposed to writhe) of helical and sigmoidal surface structures.
Helicity and the SOLIS Vector-Spectromagnetograph
Authors: Keller Christoph U. , Harvey John W. , Henney Carl J. , Jones Harrison P.
Published: March 2016

The SOLIS Vector-Spectromagnetograph (VSM) is a compact, highly efficient vector-polarimeter that measures the magnetic field vector over the full solar disk within 12 minutes. Helicity-related quantities will be derived from the observed vector field.
HST Observations of Young Stellar Clusters in Nearby Galaxies
Authors: Larsen Søren S.
Published: March 2016

The HST data archive contains images of several nearby spirals, suitable for detailed studies of the properties of individual star clusters and their surroundings. By combining structural information derived from HST images with ground-based photometry, it is possible to study cluster properties as a function of age and mass. While both the core and effective radii of young clusters correlate with mass, the slopes of these relations are shallower than for a constant-density relation, implying that the mean density increases with cluster mass. This must be accounted for in theories for cluster formation.
Star Cluster Formation in Extreme Starburst Environments
Authors: de Grijs Richard
Published: March 2016

The currently available empirical evidence on the star formation processes in the extreme, high-pressure environments induced by galaxy encounters, mostly based on high-resolution Hubble Space Telescope imaging observations, strongly suggests that star cluster formation is an important and perhaps even the dominant mode of star formation in the starburst events associated with galaxy interactions.
Stellar Populations, Butcher-Oemler Effect, Star Formation in Clusters
Authors: Poggianti Bianca M.
Published: March 2016

In this brief overview of the stellar populations of galaxies in clusters I highlight some of the most recent results, including the downsizing of the k+a population and the star formation-local density relation. I conclude discussing some open questions regarding the interpretation of the observational results, and speculating on the current meaning of the words “primordial” and “environmental”.
Can Bars be Destroyed by Central Mass Concentrations?
Authors: Athanassoula E. , Dehnen W. , Lambert J. C.
Published: March 2016

We use N-body simulations to follow the evolution of bars in the presence of a central mass concentration (CMC). We find that the bar amplitude decreases in response to the CMC, but the bar is not totally destroyed unless the CMC mass is several percent of that of the disc. More centrally concentrated CMCs are more efficient. The bar evolution does not stop after the CMC has fully grown, but continues well after that time.
“Super” Star Clusters
Authors: Grijs Richard de
Published: March 2016

The production of “super star clusters” (SSCs; luminous, compact star clusters) seems to be a hallmark of intense star formation, particularly in interacting and star-burst galaxies. Their sizes, luminosities, and mass estimates are entirely consistent with what is expected for young Milky Way-type globular clusters (GCs). SSCs are important because of what they can tell us about GC formation and evolution (e.g., initial characteristics and early survival rates). They are also of prime importance as probes of the formation and (chemical) evolution of their host galaxies, and of the initial mass function in the extreme environments required for cluster formation. Recent evidence lends support to the scenario that Milky Way-type GCs (although more metal rich), which were once thought to be the oldest building blocks of galaxies, are still forming today.
Joint Discussion 13: On Extragalactic Binaries
Authors: Ribas Ignasi , Giménez Alvaro
Published: March 2016

In this paper we discuss the impact of extragalactic binaries on astrophysics and briefly summarize the oral papers presented in Joint Discussion 13.
Binary Star Research Using the MACHO Database
Authors: Cook Kern H.
Published: March 2016

The MACHO Collaboration has produced a variable star catalog of the Magellanic Clouds which is a rich source of eclipsing binary systems. I will review the techniques that have been used by MACHO for identifying eclipsing binaries in a relatively automated fashion which is necessitated by the more than 230000 variable light curves cataloged. We have identified about 6000 eclipsing binaries using these techniques. These systems have periods ranging from hours to more than 1000 days. I will survey the binary star data from MACHO and highlight its use in investigating topics spanning the physics of supersoft gamma-ray sources to the distance of the Large Magellanic Cloud and point to future directions of research using this public resource.
Circularization in B-type Eclipsing Binaries in Both Magellanic Clouds
Authors: North P. , Zahn J.-P.
Published: March 2016

Making use of detached eclipsing binaries with B-type components discovered by the OGLE and MACHO teams in the SMC and in the LMC, we give the value of the fractional radius above which circularization occurs. This critical radius is around 0.24 to 0.26, regardless of the mass, surface gravity or metallicity, and is consistent with that found by Giuricin et al. (1984) for galactic binaries. These empirical facts are shown to be consistent with Zahn’s (1975) theory of tidal dissipation. This work confirms and extends that of North & Zahn (2003), thanks to a sample of 448 binaries taken from the recent OGLE catalogue of 2580 eclipsing binaries in the LMC (Wyrzykowski et al. 2003) and a more homogeneous interpretation of the lightcurves of the 148 SMC binaries.
Material Processing of Interstellar Dust in Comets
Authors: Kimura Hiroshi , Mann Ingrid
Published: March 2016

To better understand the processing of pristine materials in comets, we compare the composition of cometary and interstellar dust. We suggest that the deficit of N in comet dust bears evidence for the processing of the organic refractory mantle of pre-solar interstellar dust, unless it arises from the protosolar disk chemistry. The amorphous silicate core, in contrast, seems to be protected against processing due to the presence of the organic refractory mantle.
From Interstellar Matter To Comets: A Laboratory View
Authors: Ehrenfreund Pascale , Botta Oliver
Published: March 2016

Comets, formed in the cold outer parts of the solar system, provide a record of pristine material from the parent interstellar cloud. The investigation of outgassing curves from bright comets has provided a relationship to the abundances of interstellar ices and gas phase molecules. However, being porous and stratified in various layers of different densities and temperatures, the out-gassing characteristics of comets can not always be directly reconciled with the interstellar composition. This is due to the structure of the nuclear ice component, which contains different coexisting ice phases, clathrates, and trapped gases. Ices, silicates and carbonaceous compounds – studied through astronomical observations and by laboratory simulations – serve as reference material to obtain information on cometary bulk material. A major fraction of cosmic carbon in the interstellar medium, comets and meteorites seems to be incorporated into complex aromatic networks, which are difficult to observe and to identify spectroscopically. However, recent measurements of the macromolecular structure and soluble organic species in carbonaceous meteorites provide a powerful tool to investigate the link of small bodies in the solar system.
Impacts onto Cometary Nuclei
Authors: Leliwa-Kopystynski Jacek
Published: March 2016

It is expected that the Deep Impact mission will hit the Comet Tempel 1 nucleus in July 4, 2005. So, modeling of the impacts onto icy/mineral granular and porous materials, and therefore low-dense media, are very relevant. A model of result of the impact onto icy-mineral-porous target is presented on the basis of many series of impact experiments performed in the laboratories. Experimental results are extrapolated to the Deep Impact scale and farther on, to the planetary scale of collisions, e.g., to impacts of the meteorites on comet nuclei. Crucial for modeling are the parameters of the medium forming the nucleus. The most important of them are the ice to total mass ratio and the porosity. Both are virtually unknown, so they are discussed within the large ranges. Self-references. Icarus, 131, 210-222, 1998; Planet. Space Sci., 48, 1437-1446, 2000; Icarus, 158, 516-531, 2002.
Rapid Interstellar Scintillation of Quasar PKS 1257-326
Authors: Bignall Hayley E. , Jauncey David L. , Lovell James E. J. , Tzioumis Anastasios K. , Macquart Jean-Pierre , Kedziora-Chudczer Lucyna
Published: March 2016

PKS 1257—326 is one of three quasars known to show unusually large and rapid, intra-hour intensity variations, as a result of scintillation in the turbulent Galactic interstellar medium. We have measured time delays in the variability pattern arrival times at the VLA and the ATCA, as well as an annual cycle in the time-scale of variability for this source. Results of the two-station time delay observations are presented here. Implications for the scintillation of this source are discussed in the light of these results, together with results from two years of monitoring with the ATCA.
The Jets in Micro-Quasars and Quasars: A Comparison
Authors: Spencer Ralph
Published: March 2016

The discovery of relativistic jets in radio emitting X-ray binaries in our own galaxy has led to the term ‘microquasar’ being coined for these objects. In this paper the properties of microquasars are compared with those of quasars and radio galaxies, with the aim of trying to see how the similarities and differences can inform us about the physical conditions and evolution of jets. GRS1915+105 and SS433 are also discussed in more detail.
The Deep Space 1 Encounter with Comet 19P/Borrelly
Authors: Nelson Robert M.
Published: March 2016

On 22 Sept 2001 at 22h 29m 33s UTC the Deep Space 1 (DS1) spacecraft encountered the comet 19P/Borrelly at a distance of 2171 km. Measurements were undertaken by two dedicated science instruments on the spacecraft and by the spacecraft’s ion propulsion system diagnostic sensors (IDS). The images are the highest resolution ever obtained of a cometary nucleus and show topography and albedo differences on the surface at a resolution of 47m. The disk averaged geometric albedo is less than 0.03, among the lowest of any solar system object observed. The surface reflectance varies by a factor of three; the most absorbing areas having a normal reflectance of less than 0.01. Material is being emitted of from localized regions on the nucleus generally in the sunward direction. These regions are cylindrically shaped about 0.5 km in diameter and about 5 km in length. The cometary bow shock and other features associated with the cometary environs are asymmetrically offset from the sun-Borrelly axis. This suggests that the localized emission regions seen in the images may cause the coma to be asymmetrically offset from the sun-nucleus line. Such an offset has not been reported in previous spacecraft encounters with other comets.
Volcanism on Io: the Post-Galileo View, and a Comparison with Earth
Authors: Davies Ashley Gerard
Published: March 2016

At the end of the Galileo mission in September 2003, and approximately three years after the Cassini Jovian flyby, it is an appropriate time to reflect on the recent advances made in Io science. Data have been analyzed and volcanic processes have begun to be quantified. This paper reviews these advances from a purely volcano-logical perspective, looking at particular volcanos of interest, and comparing styles of ionian activity with those seen on Earth.
Characterization of the Zonal Wind Flow in the Upper Atmosphere of Titan with the VLT
Authors: Courtin Régis , Luz David , Gautier Daniel , Appourchaux Thierry , Lebreton Jean-Pierre , Ferri Francesca , Lara Luisa , Hourdin Frédéric , Kaufer Andreas
Published: March 2016

We report on recent efforts to characterize the zonal wind flow in the upper atmosphere of Titan from high resolution spectroscopic observations with the Very Large Telescope.
The Huygens Mission to Titan: Overview and status
Authors: Lebreton J.-P. , Matson D. L.
Published: March 2016

Huygens is an entry probe designed to descend under parachute through the atmosphere of Titan, Saturn’s largest moon. The Huygens Probe is provided by the European Space Agency (ESA) for the Cassini/Huygens mission to Saturn and Titan. The Huygens mission will be conducted on the 3rd Orbit around Saturn. The probe will be released around December 25, 2004 for entry in Titan on January 14, 2005. This paper provided an overview of the Huygens mission. The status of the probe and of the mission was reviewed, and opportunities for Titan observations by the Orbiter during the first two orbits were discussed. The Cassini/Huygens mission is a joint undertaking by NASA and ESA, with ASI as a partner via a bilateral agreement with NASA.
ASTROD I: Mission Concept and Venus Flybys
Authors: Li Guangyu , Ni Wei-Tou , Tang Chien-Jen
Published: March 2016

ASTROD I with one spacecraft ranging optically with ground stations is a first step for a full ASTROD (Astrodynamical Space Test of Relativity using Optical Devices) mission. The goals are testing relativity with the relativistic parameter γ measured to 10~7, measuring solar-system parameters more precisely, and improving the present-day sensitivity for gravitational wave detection using Doppler tracking by radio waves. In this paper, we present the mission concept and the orbit design for ASTROD I with an emphasis on Venus flybys. The spacecraft is to be launched into an inner solar orbit with initial period about 290 days to encounter Venus twice to receive gravity-assistance for achieving shorter period (165 days or less) to reach the other side of the Sun for a sooner measurement of Shapiro time delay. For a launch on June 17, 2010, after two encounters with Venus, the orbital period can be shortened to 165 days and the spacecraft orbit reaches inside Mercury orbit. After about 400 days from launch, the spacecraft will arrive at the other side of the Sun and the relativistic parameter γ can be determined to 0.1 ppm or better. A simulation of the accuracy for determining the relativistic parameters γ and β, and the solar quadrupole parameter J2 gives 10−7, 10−7 and 10−8 for their respective uncertainties. In this simulation, we assume a 10 ps timing accuracy and 10−13 m/s2(Hz)1/2 at frequency f ~ 100μHz inertial sensor/accelerometer noise. Other orbits separated by synodic periods of Venus can readily be found. We discuss the sensitivity and noise reduction requirements, the atmosphere transmission noise, timing noise, spacecraft environmental noise, test-mass sensor back-action, and test mass-spacecraft control-loop noise and stiffness. In the second Venus flyby, the ASTROD I could also be swung into an elliptic 360-day orbit and stay near opposite side of the Sun for many good measurements of the Shapiro time delays — 19 times in 10 years. This is an interesting alternative. In the two Venus flybys, Venus multiple moments can be determined very precisely. In this paper, we also review ASTROD and discuss its gravitational-wave sensitivities.
The Cultural Backdrop to Prospection: Exploring the Relevance of Time–Space Distanciation
Authors: Palitsky Roman , Sullivan Daniel , Keefer Lucas A. , Stewart Sheridan A.
Published: March 2016

Although the phenomena of prospection are embedded within cultural contexts, the impact of culture on prospection has not been subjected to systematic study. Drawing on theory and research in social and environmental psychology, sociology, and anthropology, we observe that time and space are heterogeneously organized and understood across different cultural settings, and propose that the cultural organization of time and space impacts the processes of prospection. We employ the construct of time–space distanciation (TSD), first introduced by Anthony Giddens, to describe the relationship between culture and understandings of time and space. TSD refers to the process through which cultural assumptions about the relationship between time and space change attributable to technological, economic, and social structural transitions. We present a diachronic account of changes in TSD (focusing on postindustrial societies), followed by a review of the applications of this construct for current prospection theory and research. TSD introduces a useful means for organizing broad social factors such as wealth, technology, and ideology, and bringing them into relation with individuals’ processes of prospection, by looking at the relationships between time and space presumed within cultures.
Prospection in Individual and Interpersonal Corruption Dilemmas
Authors: Köbis Nils C. , van Prooijen Jan-Willem , Righetti Francesca , Van Lange Paul A. M.
Published: March 2016

Corruption represents 1 of the main societal challenges of our time. At present, there is no theoretical framework distinguishing the prospective decision-making processes involved in different acts of corruption. We differentiate between 2 broad categories of corrupt acts that have different implications for prospective cognition: individual corrupt acts, which refer to a power holder individually abusing entrusted power; and interpersonal corrupt acts, which refer to a power holder abusing entrusted power in collaboration with other corrupt agents. We model the decision structure as 2 inherently different social dilemmas: individual corruption requires a power holder to prospect own and collective consequences, whereas interpersonal corruption requires a prospection of self-interest, the interest of corrupt partner(s) conflict and collective interests (nested social dilemma). Individual and interpersonal corruption rest on different prospective decision-making processes, which we illustrate along intrapersonal factors (prospection of costs and benefits, self-control, guilt) and interpersonal factors (social norms, trust). We explore the advantages of this novel distinction for theory development, experimental corruption research, as well as anticorruption efforts.
Cultural Differences between East Asian and North American in Temporal Orientation
Authors: Gao Xuan
Published: March 2016

Based on East Asian and North American differences in holistic versus analytical cognitive processing style and the tendency to predict cyclical versus linear trends, this review proposes cultural differences in their temporal orientation. Building on prior research that has compared the cultural differences on past, present, and future orientation, this review hypothesizes that East Asians focus on the past and future more than North Americans, and North Americans focus on the present more than East Asians. It is suggested that in addition to a cultural difference in the focus on the 3 temporal domains, when moving from any past or future time point toward the present, North Americans’ focus on the temporal domain grows more than East Asians’ focus. I present evidence in three categories based on how temporal orientation is defined. Specially, I compare East Asians’ and North Americans’ focus on a temporal domain, their mental representation of a temporal domain and their subjective temporal distance to a temporal domain.
Introduction to the Special Issue: The Science of Prospection
Authors: Baumeister Roy F. , Vohs Kathleen D.
Published: March 2016

Psychology's main theories explain human behavior by pointing to the past: childhood experiences, socialization, reinforcement history. Yet recent evidence has suggested that people do not spend much time actively thinking about the past. The articles in this special issue reflect a growing sentiment that prospection should be a central focus of psychology. They are about 2 central themes: prediction and pragmatic planning. Prediction studies are largely about when people make predictions and their accuracy (including what mistakes people make). Pragmatic planning, which from evolutionary standpoints might be the more common and basic form of thinking about the future, involves anticipating what a person will have to do, decide, perform. The 2 approaches are quite compatible: prediction in service of pragmatic adjustments would be highly adaptive. To accurately imagine what might happen is likely not an end to itself, because that alone does not enable a person to make changes or ready oneself for the event if and when it comes to fruition. The articles in this special issue—whether on prospection, prediction, pragmatic planning, or prediction in service of preparation and planning—suggest avenues to pave the way for psychology's brightest future.
Plasma cell alloantigen ENPP1 is expressed by a subset of human B cells with potential regulatory functions
Authors: Yoon Jeongheon , Wang Hongsheng , Kim Yong Chan , Yoshimoto Momoko , Abbasi Sadia , Morse Herbert C
Published: March 2016

Plasma cell alloantigen 1 (PC1), also known as ENPP1 (ectonucleotide pyrophosphatase/phosphodiesterase 1), is an enzyme involved primarily in hydrolysis of adenosine triphosphate at the cell surface. Although the expression pattern of PC1 is relatively broad, its expression in B cells is found at significant levels only in terminally differentiated germinal center B cells, plasma cells and a subset of B‐1a cells in mice. Here we describe studies designed to determine whether expression of PC1 might define novel populations of human B cells with similarities to mouse B cells. We found that PC1 is expressed in small populations of human B lineage cells in peripheral blood, cord blood, tonsils, bone marrow and pediatric peritoneal fluid, with the highest levels in plasma cells. The characteristics of human PC1+ B cells differ from mouse peritoneal B‐1a subsets and from features of the human CD20+CD27+CD43+CD70− B‐cell subset proposed to be human B‐1 cells. Expression of PC1 was greatly increased in B cells stimulated with the combination of CD40 ligand, interleukin (IL)‐4 and IL‐21. In addition, PC1+ B cells activated CD4+ T regulatory cells. ENPP1 thus defines a subset of human B cells that differs significantly from mouse peritoneal B‐1a and proposed human B‐1 cells.
Reconstruction and topological characterization of the sigma factor regulatory network of Mycobacterium tuberculosis
Authors: Chauhan Rinki , Ravi Janani , Datta Pratik , Chen Tianlong , Schnappinger Dirk , Bassler Kevin E. , Balázsi Gábor , Gennaro Maria Laura
Published: March 2016

Accessory sigma factors, which reprogram RNA polymerase to transcribe specific gene sets, activate bacterial adaptive responses to noxious environments. Here we reconstruct the complete sigma factor regulatory network of the human pathogen Mycobacterium tuberculosis by an integrated approach. The approach combines identification of direct regulatory interactions between M. tuberculosis sigma factors in an E. coli model system, validation of selected links in M. tuberculosis, and extensive literature review. The resulting network comprises 41 direct interactions among all 13 sigma factors. Analysis of network topology reveals (i) a three-tiered hierarchy initiating at master regulators, (ii) high connectivity and (iii) distinct communities containing multiple sigma factors. These topological features are likely associated with multi-layer signal processing and specialized stress responses involving multiple sigma factors. Moreover, the identification of overrepresented network motifs, such as autoregulation and coregulation of sigma and anti-sigma factor pairs, provides structural information that is relevant for studies of network dynamics.
Laboratory observations of slow earthquakes and the spectrum of tectonic fault slip modes
Authors: Leeman J. R. , Saffer D. M. , Scuderi M. M. , Marone C.
Published: March 2016

Slow earthquakes represent an important conundrum in earthquake physics. While regular earthquakes are catastrophic events with rupture velocities governed by elastic wave speed, the processes that underlie slow fault slip phenomena, including recent discoveries of tremor, slow-slip and low-frequency earthquakes, are less understood. Theoretical models and sparse laboratory observations have provided insights, but the physics of slow fault rupture remain enigmatic. Here we report on laboratory observations that illuminate the mechanics of slow-slip phenomena. We show that a spectrum of slow-slip behaviours arises near the threshold between stable and unstable failure, and is governed by frictional dynamics via the interplay of fault frictional properties, effective normal stress and the elastic stiffness of the surrounding material. This generalizable frictional mechanism may act in concert with other hypothesized processes that damp dynamic ruptures, and is consistent with the broad range of geologic environments where slow earthquakes are observed.
Topological vacuum bubbles by anyon braiding
Authors: Han Cheolhee , Park Jinhong , Gefen Yuval , Sim H.-S.
Published: March 2016

According to a basic rule of fermionic and bosonic many-body physics, known as the linked cluster theorem, physical observables are not affected by vacuum bubbles, which represent virtual particles created from vacuum and self-annihilating without interacting with real particles. Here we show that this conventional knowledge must be revised for anyons, quasiparticles that obey fractional exchange statistics intermediate between fermions and bosons. We find that a certain class of vacuum bubbles of Abelian anyons does affect physical observables. They represent virtually excited anyons that wind around real anyonic excitations. These topological bubbles result in a temperature-dependent phase shift of Fabry–Perot interference patterns in the fractional quantum Hall regime accessible in current experiments, thus providing a tool for direct and unambiguous observation of elusive fractional statistics.
Chirality of nanophotonic waveguide with embedded quantum emitter for unidirectional spin transfer
Authors: Coles R. J. , Price D. M. , Dixon J. E. , Royall B. , Clarke E. , Kok P. , Skolnick M. S. , Fox A. M. , Makhonin M. N.
Published: March 2016

Scalable quantum technologies may be achieved by faithful conversion between matter qubits and photonic qubits in integrated circuit geometries. Within this context, quantum dots possess well-defined spin states (matter qubits), which couple efficiently to photons. By embedding them in nanophotonic waveguides, they provide a promising platform for quantum technology implementations. In this paper, we demonstrate that the naturally occurring electromagnetic field chirality that arises in nanobeam waveguides leads to unidirectional photon emission from quantum dot spin states, with resultant in-plane transfer of matter-qubit information. The chiral behaviour occurs despite the non-chiral geometry and material of the waveguides. Using dot registration techniques, we achieve a quantum emitter deterministically positioned at a chiral point and realize spin-path conversion by design. We further show that the chiral phenomena are much more tolerant to dot position than in standard photonic crystal waveguides, exhibit spin-path readout up to 95±5% and have potential to serve as the basis of spin-logic and network implementations.
Systematic quantification of HDR and NHEJ reveals effects of locus, nuclease, and cell type on genome-editing
Authors: Miyaoka Yuichiro , Berman Jennifer R. , Cooper Samantha B. , Mayerl Steven J. , Chan Amanda H. , Zhang Bin , Karlin-Neumann George A. , Conklin Bruce R.
Published: March 2016

Precise genome-editing relies on the repair of sequence-specific nuclease-induced DNA nicking or double-strand breaks (DSBs) by homology-directed repair (HDR). However, nonhomologous end-joining (NHEJ), an error-prone repair, acts concurrently, reducing the rate of high-fidelity edits. The identification of genome-editing conditions that favor HDR over NHEJ has been hindered by the lack of a simple method to measure HDR and NHEJ directly and simultaneously at endogenous loci. To overcome this challenge, we developed a novel, rapid, digital PCR–based assay that can simultaneously detect one HDR or NHEJ event out of 1,000 copies of the genome. Using this assay, we systematically monitored genome-editing outcomes of CRISPR-associated protein 9 (Cas9), Cas9 nickases, catalytically dead Cas9 fused to FokI, and transcription activator–like effector nuclease at three disease-associated endogenous gene loci in HEK293T cells, HeLa cells, and human induced pluripotent stem cells. Although it is widely thought that NHEJ generally occurs more often than HDR, we found that more HDR than NHEJ was induced under multiple conditions. Surprisingly, the HDR/NHEJ ratios were highly dependent on gene locus, nuclease platform, and cell type. The new assay system, and our findings based on it, will enable mechanistic studies of genome-editing and help improve genome-editing technology.
Inhibitory Effect of Sophorolipid on Candida albicans Biofilm Formation and Hyphal Growth
Authors: Haque Farazul , Alfatah Md. , Ganesan K. , Bhattacharyya Mani Shankar
Published: March 2016

Candida albicans causes superficial and life-threatening systemic infections. These are difficult to treat often due to drug resistance, particularly because C. albicans biofilms are inherently resistant to most antifungals. Sophorolipid (SL), a glycolipid biosurfactant, has been shown to have antimicrobial and anticancer properties. In this study, we investigated the effect of SL on C. albicans biofilm formation and preformed biofilms. SL was found to inhibit C. albicans biofilm formation as well as reduce the viability of preformed biofilms. Moreover, SL, when used along with amphotericin B (AmB) or fluconazole (FLZ), was found to act synergistically against biofilm formation and preformed biofilms. Effect of SL on C. albicans biofilm formation was further visualized by scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM), which revealed absence of hyphae, typical biofilm architecture and alteration in the morphology of biofilm cells. We also found that SL downregulates the expression of hypha specific genes HWP1, ALS1, ALS3, ECE1 and SAP4, which possibly explains the inhibitory effect of SL on hyphae and biofilm formation.
Transplantation of Defined Populations of Differentiated Human Neural Stem Cell Progeny
Authors: Fortin Jeff M. , Azari Hassan , Zheng Tong , Darioosh Roya P. , Schmoll Michael E. , Vedam-Mai Vinata , Deleyrolle Loic P. , Reynolds Brent A.
Published: March 2016

Many neurological injuries are likely too extensive for the limited repair capacity of endogenous neural stem cells (NSCs). An alternative is to isolate NSCs from a donor and expand them in vitro as transplantation material. Numerous groups have already transplanted neural stem and precursor cells. A caveat to this approach is the undefined phenotypic distribution of the donor cells, which has three principle drawbacks: (1) Stem-like cells retain the capacity to proliferate in vivo. (2) There is little control over the cells’ terminal differentiation, e.g., a graft intended to replace neurons might choose a predominantly glial fate. (3) There is limited ability of researchers to alter the combination of cell types in pursuit of a precise treatment. We demonstrate a procedure for differentiating human neural precursor cells (hNPCs) in vitro, followed by isolation of the neuronal progeny. We transplanted undifferentiated hNPCs or a defined concentration of hNPC-derived neurons into mice, then compared these two groups with regard to their survival, proliferation and phenotypic fate. We present evidence suggesting that in vitro-differentiated-and-purified neurons survive as well in vivo as their undifferentiated progenitors and undergo less proliferation and less astrocytic differentiation. We also describe techniques for optimizing low-temperature cell preservation and portability.
Two host microRNAs influence WSSV replication via STAT gene regulation
Authors: Huang Ying , Wang Wen , Ren Qian
Published: March 2016

MicroRNAs (miRNAs) have important roles in post-transcriptional regulation of gene expression. During viral infection, viruses utilize hosts to enhance their replication by altering cellular miRNAs. The Janus kinase (JAK)/signal transducer and activator of transcription (STAT) pathway plays crucial roles in the antiviral responses. In this study, two miRNAs (miR-9041 and miR-9850) from Macrobrachium rosenbergii were found to promote white spot syndrome virus (WSSV) replication. The up-regulation of miR-9041 or miR-9850 suppresses STAT expression in the gills of M. rosenbergii, which subsequently down-regulates the expression of its downstream dynamin (Dnm) genes: Dnm1, Dnm2, and Dnm3. Knockdown of miR-9041 and miR-9850 restricts WSSV replication by up-regulating STAT and Dnm gene expression. The silencing of STAT, Dnm1, Dnm2, or Dnm3 led to an increase of the number of WSSV copies in shrimp. The injection of recombinant Dnm1, Dnm2, or Dnm3 proteins could inhibit WSSV replication in vivo. Overall, our research indicates the roles of host miRNAs in the enhancement of WSSV replication by regulating the host JAK/STAT pathway.
Oligomerization as a strategy for cold adaptation: Structure and dynamics of the GH1 β-glucosidase from Exiguobacterium antarcticum B7
Authors: Zanphorlin Leticia Maria , de Giuseppe Priscila Oliveira , Honorato Rodrigo Vargas , Tonoli Celisa Caldana Costa , Fattori Juliana , Crespim Elaine , de Oliveira Paulo Sergio Lopes , Ruller Roberto , Murakami Mario Tyago
Published: March 2016

Psychrophilic enzymes evolved from a plethora of structural scaffolds via multiple molecular pathways. Elucidating their adaptive strategies is instrumental to understand how life can thrive in cold ecosystems and to tailor enzymes for biotechnological applications at low temperatures. In this work, we used X-ray crystallography,in solutionstudies and molecular dynamics simulations to reveal the structural basis for cold adaptation of the GH1 β-glucosidase fromExiguobacterium antarcticumB7. We discovered that the selective pressure of low temperatures favored mutations that redesigned the protein surface, reduced the number of salt bridges, exposed more hydrophobic regions to the solvent and gave rise to a tetrameric arrangement not found in mesophilic and thermophilic homologues. As a result, some solvent-exposed regions became more flexible in the cold-adapted tetramer, likely contributing to enhance enzymatic activity at cold environments. The tetramer stabilizes the native conformation of the enzyme, leading to a 10-fold higher activity compared to the disassembled monomers. According to phylogenetic analysis, diverse adaptive strategies to cold environments emerged in the GH1 family, being tetramerization an alternative, not a rule. These findings reveal a novel strategy for enzyme cold adaptation and provide a framework for the semi-rational engineering of β-glucosidases aiming at cold industrial processes.
The transfer of titanium dioxide nanoparticles from the host plant to butterfly larvae through a food chain
Authors: Kubo-Irie Miyoko , Yokoyama Masaaki , Shinkai Yusuke , Niki Rikio , Takeda Ken , Irie Masaru
Published: March 2016

This study aimed to examine the transfer of nanoparticles within a terrestrial food chain. Oviposited eggs of the swallowtail butterfly (Atrophaneura alcinous) were hatched on the leaves of the host plant (Aristolochia debilis) and the root stock and root hairs were submerged in a suspension of 10 μg/ml titanium dioxide nanoparticles (TiO2-NPs) in a 100 ml bottle. The presence of TiO2-NPs in the veins of the leaves was confirmed by X-ray analytical microscopy (X-ray AM). The hatched 1st instar larvae fed on the leaves to moult into 2nd instar larvae. Small agglomerates of TiO2-NPs less than 150 nm in diameter were identified in the vascular tissue of the exposed plant, the midgut and the excreta of the larvae by transmission electron microscopy. The image of Ti elemental mapping by X-ray AM was analysed with the quantitative spatial information mapping (QSIM) technique. The results demonstrated that TiO2-NPs were transferred from the plant to the larvae and they were disseminated throughout the environment via larval excreta.
Sex reversal assessments reveal different vulnerability to endocrine disruption between deeply diverged anuran lineages
Authors: Tamschick Stephanie , Rozenblut-Kościsty Beata , Ogielska Maria , Lehmann Andreas , Lymberakis Petros , Hoffmann Frauke , Lutz Ilka , Kloas Werner , Stöck Matthias
Published: March 2016

Multiple anthropogenic stressors cause worldwide amphibian declines. Among several poorly investigated causes is global pollution of aquatic ecosystems with endocrine disrupting compounds (EDCs). These substances interfere with the endocrine system and can affect the sexual development of vertebrates including amphibians. We test the susceptibility to an environmentally relevant contraceptive, the artificial estrogen 17α-ethinylestradiol (EE2), simultaneously in three deeply divergent systematic anuran families, a model-species,Xenopus laevis(Pipidae) and two non-models,Hyla arborea(Hylidae) andBufo viridis(Bufonidae). Our new approach combines synchronized tadpole exposure to three EE2-concentrations (50, 500, 5,000 ng/L) in a flow-through-system and pioneers genetic and histological sexing of metamorphs in non-model anurans for EDC-studies. This novel methodology reveals striking quantitative differences in genetic-male-to-phenotypic-female sex reversal in non-model vs. model species. Our findings qualify molecular sexing in EDC-analyses as requirement to identify sex reversals and state-of-the-art approaches as mandatory to detect species-specific vulnerabilities to EDCs in amphibians.
Redox proteins of hydroxylating bacterial dioxygenases establish a regulatory cascade that prevents gratuitous induction of tetralin biodegradation genes
Authors: Ledesma-García Laura , Sánchez-Azqueta Ana , Medina Milagros , Reyes-Ramírez Francisca , Santero Eduardo
Published: March 2016

Bacterial dioxygenase systems are multicomponent enzymes that catalyze the initial degradation of many environmentally hazardous compounds. In Sphingopyxis granuli strain TFA tetralin dioxygenase hydroxylates tetralin, an organic contaminant. It consists of a ferredoxin reductase (ThnA4), a ferredoxin (ThnA3) and a oxygenase (ThnA1/ThnA2), forming a NAD(P)H–ThnA4–ThnA3–ThnA1/ThnA2 electron transport chain. ThnA3 has also a regulatory function since it prevents expression of tetralin degradation genes (thn) in the presence of non-metabolizable substrates of the catabolic pathway. This role is of physiological relevance since avoids gratuitous and wasteful production of catabolic enzymes. Our hypothesis for thn regulation implies that ThnA3 exerts its action by diverting electrons towards the regulator ThnY, an iron-sulfur flavoprotein that together with the transcriptional activator ThnR is necessary for thn gene expression. Here we analyze electron transfer among ThnA4, ThnA3 and ThnY by using stopped-flow spectrophotometry and determination of midpoint reduction potentials. Our results indicate that when accumulated in its reduced form ThnA3 is able to fully reduce ThnY. In addition, we have reproduced in vitro the regulatory circuit in the proposed physiological direction, NAD(P)H–ThnA4–ThnA3–ThnY. ThnA3 represents an unprecedented way of communication between a catabolic pathway and its regulatory system to prevent gratuitous induction.
Homonuclear decoupling for spectral simplification of carbon-13 enriched molecules in solution-state NMR enhanced by dissolution DNP
Authors: Chinthalapalli Srinivas , Bornet Aurélien , Carnevale Diego , Jannin Sami , Bodenhausen Geoffrey
Published: March 2016

Complex overlapping multiplets due to scalar couplingsnJ(13C,13C) in fully13C-enriched molecules can be simplified by polychromatic irradiation of selected spins.
Highly purified CNTs: an exceedingly efficient catalyst support for PEM fuel cell
Authors: Gupta Chanchal , Maheshwari Priyanka H. , Sachdev Divya , Sahu A. K. , Dhakate S. R.
Published: March 2016

High performance in PEM fuel cells has been achieved using purified CNTs as catalyst support.
Targeted design leads to tunable photoluminescence from perylene dicarboxdiimide–poly(oxyalkylene)/siloxane hybrids for luminescent solar concentrators
Authors: Meazzini Ilaria , Willis-Fox Niamh , Blayo Camille , Arlt Jochen , Clément Sébastien , Evans Rachel C.
Published: March 2016

The chain length and branching of the organic backbone of poly(oxyalkylene)/siloxane ureasils can be used to control the placement and orientation of a covalently-grafted perylene, leading to tunable photoluminescence.
Understanding thermoelectric properties from high-throughput calculations: trends, insights, and comparisons with experiment
Authors: Chen Wei , Pöhls Jan-Hendrik , Hautier Geoffroy , Broberg Danny , Bajaj Saurabh , Aydemir Umut , Gibbs Zachary M. , Zhu Hong , Asta Mark , Snyder G. Jeffrey , Meredig Bryce , White Mary Anne , Persson Kristin , Jain Anubhav
Published: March 2016

An overview of computed thermoelectric properties for more than 48 000 inorganic compounds from the Materials Project (MP).
Sensing activity of cholinesterases through a luminescence response of the hexarhenium cluster complex [{Re6S8}(OH)6]4−
Authors: Elistratova Julia G. , Mustafina Asiya R. , Brylev Konstantin A. , Petrov Konstantin A. , Shestopalov Michael A. , Mironov Yuri V. , Babaev Vasily M. , Rizvanov Ildar K. , Masson Patrick , Sinyashin Oleg G.
Published: March 2016

A new method to sense enzymatic hydrolysis of acetylcholine through a cluster luminescence.
Synergistic effect of Au and Rh on SrTiO3in significantly promoting visible-light-driven syngas production from CO2and H2O
Authors: Li Dewang , Ouyang Shuxin , Xu Hua , Lu Da , Zhao Ming , Zhang Xueliang , Ye Jinhua
Published: March 2016

A novel photocatalyst, Rh and Au coloaded SrTiO3, enables syngas photosynthesis to be realized under visible-light irradiation; the synergistic effect of Rh and Au plays a significant role in achieving enhanced photoactivity.
The stereoselective synthesis of dienes through dehalogenative homocoupling of terminal alkenyl bromides on Cu(110)
Authors: Sun Qiang , Cai Liangliang , Ma Honghong , Yuan Chunxue , Xu Wei
Published: March 2016

We have successfully achieved the stereoselective synthesis of a specific cis-diene moiety through a dehalogenative homocoupling of alkenyl bromides on the Cu(110) surface.
Nitrogen-doped carbon nanotube as a potential metal-free catalyst for CO oxidation
Authors: Lin I-Hsiang , Lu Yu-Huan , Chen Hsin-Tsung
Published: March 2016

We elucidate the possibility of nitrogen-doped carbon nanotube as a robust catalyst for CO oxidation.
Isothermal microcalorimetry as a tool to study solid–electrolyte interphase formation in lithium-ion cells
Authors: Hall David S. , Glazier Stephen L. , Dahn J. R.
Published: March 2016

Isothermal microcalorimetry can be used in conjunction with electrochemical measurements to study solid–electrolyte interphase (SEI) formation reactions as they occur in a Li-ion cell.