Suppression of backward scattering of Dirac fermions in iron pnictides Ba(Fe1−x_{1-x}Rux_xAs)2_2

We report electronic transport of Dirac cones when Fe is replaced by Ru, which has an isoelectronic electron configuration to Fe, using single crystals of Ba(Fe$_{1-x}$Ru$_x$As)$_2$. The electronic transport of parabolic bands is shown to be suppressed by scattering due to the crystal lattice distortion and the impurity effect of Ru, while that of the Dirac cone is not significantly reduced due to the intrinsic character of Dirac cones. It is clearly shown from magnetoresistance and Hall coefficient measurements that the inverse of average mobility, proportional to cyclotron effective mass, develops as the square root of the carrier number (n) of the Dirac cones. This is the unique character of the Dirac cone linear dispersion relationship. Scattering of Ru on the Dirac cones is discussed in terms of the estimated mean free path using experimental parameters.Comment: 6 pages, 3 figures, To be published in Phys. Rev.

The Infrared Properties of Submillimeter Galaxies: Clues From Ultra-Deep 70 Micron Imaging

We present 70 micron properties of submillimeter galaxies (SMGs) in the Great Observatories Origins Deep Survey (GOODS) North field. Out of thirty submillimeter galaxies (S_850 > 2 mJy) in the central GOODS-N region, we find two with secure 70 micron detections. These are the first 70 micron detections of SMGs. One of the matched SMGs is at z ~ 0.5 and has S_70/S_850 and S_70/S_24 ratios consistent with a cool galaxy. The second SMG (z = 1.2) has infrared-submm colors which indicate it is more actively forming stars. We examine the average 70 micron properties of the SMGs by performing a stacking analysis, which also allows us to estimate that S_850 > 2 mJy SMGs contribute 9 +- 3% of the 70 micron background light. The S_850/S_70 colors of the SMG population as a whole is best fit by cool galaxies, and because of the redshifting effects these constraints are mainly on the lower z sub-sample. We fit Spectral Energy Distributions (SEDs) to the far-infrared data points of the two detected SMGs and the average low redshift SMG (z_{median}= 1.4). We find that the average low-z SMG has a cooler dust temperature than local ultraluminous infrared galaxies (ULIRGs) of similar luminosity and an SED which is best fit by scaled up versions of normal spiral galaxies. The average low-z SMG is found to have a typical dust temperature T = 21 -- 33 K and infrared luminosity L_{8-1000 micron} = 8.0 \times 10^11 L_sun. We estimate the AGN contribution to the total infrared luminosity of low-z SMGs is less than 23%.Comment: Accepted by ApJ. 14 pages, 6 figures. Minor revisions 20th Dec 200

Y-aminobutyric acid type B (GABAB) receptor expression is needed for inhibition of N-type (Cav2.2) calcium channels by analgesic a-conotoxins

Background: A class of analgesic a-conotoxins potently inhibits N-type calcium channels. Results: The activity of a-conotoxins Vc1.1 and RgIA was reduced following knockdown of GABAB receptor expression in sensory neurons and can be reconstituted in HEK293 cells expressing human GABAB receptor and Cav2.2. Conclusion: GABAB receptors are needed for inhibition of Cav2.2 by Vc1.1 and RgIA. Significance: These analgesic a-conotoxins activate human GABAB receptors

Phase field modeling and computer implementation: A review

This paper presents an overview of the theories and computer implementation aspects of phase field models (PFM) of fracture. The advantage of PFM over discontinuous approaches to fracture is that PFM can elegantly simulate complicated fracture processes including fracture initiation, propagation, coalescence, and branching by using only a scalar field, the phase field. In addition, fracture is a natural outcome of the simulation and obtained through the solution of an additional differential equation related to the phase field. No extra fracture criteria are needed and an explicit representation of a crack surface as well as complex track crack procedures are avoided in PFM for fracture, which in turn dramatically facilitates the implementation. The PFM is thermodynamically consistent and can be easily extended to multi-physics problem by 'changing' the energy functional accordingly. Besides an overview of different PFMs, we also present comparative numerical benchmark examples to show the capability of PFMs

Heat flow and calculus on metric measure spaces with Ricci curvature bounded below - the compact case

We provide a quick overview of various calculus tools and of the main results concerning the heat flow on compact metric measure spaces, with applications to spaces with lower Ricci curvature bounds. Topics include the Hopf-Lax semigroup and the Hamilton-Jacobi equation in metric spaces, a new approach to differentiation and to the theory of Sobolev spaces over metric measure spaces, the equivalence of the L^2-gradient flow of a suitably defined "Dirichlet energy" and the Wasserstein gradient flow of the relative entropy functional, a metric version of Brenier's Theorem, and a new (stronger) definition of Ricci curvature bound from below for metric measure spaces. This new notion is stable w.r.t. measured Gromov-Hausdorff convergence and it is strictly connected with the linearity of the heat flow.Comment: To the memory of Enrico Magenes, whose exemplar life, research and teaching shaped generations of mathematician

Musical Activities, Prosocial Behaviors, and Executive Function Skills of Kindergarten Children

Prosocial behaviors and executive function are staples of child development. Engagement in music has been associated with enhanced prosocial behaviors and executive function skills in children and youth. Yet, research concerning the role of formal music programs in the development of these important behaviors and skills remains elusive. The aim of this exploratory study was to investigate the role of a 5-week music program on prosocial behaviors (instrumental helping and sharing) and executive function skills (cognitive flexibility and working memory/inhibition control) of 103 kindergarten children from two public schools in a large urban center in the United States, serving predominantly Latinx children from underserved communities. Our data suggested that the short music program positively influenced children's cognitive flexibility, but not working memory, nor prosocial skills (sharing and helping). Findings are discussed in light of earlier studies, methodological issues, and limitations, and in relation to developmental and cultural issues surrounding child participants. Implications for future research and practice are outlined

Characterizing the radio continuum emission from intense starburst galaxies

© 2016 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.The intrinsic thermal (free-free) and non-thermal (synchrotron) emission components that comprise the radio continuum of galaxies represent unique, dust-free measures of star formation rates (SFR). Such high SFR galaxies will dominate the deepest current and future radio surveys. We disentangle the thermal and non-thermal emission components of the radio continuum of six ultraluminous infrared galaxies (LFIR > 1012.5 L?) at redshifts of 0.2 = z = 0.5 and 22 IR selected galaxies. Radio data over a wide frequency range (0.8 < ? <10 GHz) are fitted with a star-forming galaxy model comprising of thermal and non-thermal components. The luminosities of both radio continuum components are strongly correlated to the 60 µm luminosity across many orders of magnitude (consistent with the far-IR to radio correlation). We demonstrate that the spectral index of the radio continuum spectral energy distribution is a useful proxy for the thermal fraction. We also find that there is an increase in mean and scatter of the thermal fraction with FIR to radio luminosity ratio which could be influenced by different time-scales of the thermal and non-thermal emission mechanisms

High-resolution VLA Imaging of SDSS Stripe 82 at 1.4 GHz

We present a high-resolution radio survey of the Sloan Digital Sky Survey (SDSS) Southern Equatorial Stripe, a.k.a. Stripe 82. This 1.4 GHz survey was conducted with the Very Large Array (VLA) primarily in the A-configuration, with supplemental B-configuration data to increase sensitivity to extended structure. The survey has an angular resolution of 1.8" and achieves a median rms noise of 52 microJy/bm over 92 deg^2. This is the deepest 1.4 GHz survey to achieve this large of an area, filling a gap in the phase space between small, deep and large, shallow surveys. It also serves as a pilot project for a larger high-resolution survey with the Expanded Very Large Array (EVLA). We discuss the technical design of the survey and details of the observations, and we outline our method for data reduction. We present a catalog of 17,969 isolated radio components, for an overall source density of ~195 sources/deg^2. The astrometric accuracy of the data is excellent, with an internal check utilizing multiply-observed sources yielding an rms scatter of 0.19" in both right ascension and declination. A comparison to the SDSS DR7 Quasar Catalog further confirms that the astrometry is well tied to the optical reference frame, with mean offsets of 0.02" +/- 0.01" in right ascension, and 0.01" +/- 0.02" in declination. A check of our photometry reveals a small, negative CLEAN-like bias on the level of 35 microJy. We report on the catalog completeness, finding that 97% of FIRST-detected quasars are recovered in the new Stripe 82 radio catalog, while faint, extended sources are more likely to be resolved out by the resolution bias. We conclude with a discussion of the optical counterparts to the catalog sources, including 76 newly-detected radio quasars. The full catalog as well as a search page and cutout server are available online at http://third.ucllnl.org/cgi-bin/stripe82cutout.Comment: 18 pages, 22, figures. Submitted to AJ, revised to address referee's comment

The Comoving Infrared Luminosity Density: Domination of Cold Galaxies across 0<z<1

In this paper we examine the contribution of galaxies with different infrared (IR) spectral energy distributions (SEDs) to the comoving infrared luminosity density, a proxy for the comoving star formation rate (SFR) density. We characterise galaxies as having either a cold or hot IR SED depending upon whether the rest-frame wavelength of their peak IR energy output is above or below 90um. Our work is based on a far-IR selected sample both in the local Universe and at high redshift, the former consisting of IRAS 60um-selected galaxies at z<0.07 and the latter of Spitzer 70um selected galaxies across 0.1<z<1. We find that the total IR luminosity densities for each redshift/luminosity bin agree well with results derived from other deep mid/far-IR surveys. At z<0.07 we observe the previously known results: that moderate luminosity galaxies (L_IR<10^11 Lsun) dominate the total luminosity density and that the fraction of cold galaxies decreases with increasing luminosity, becoming negligible at the highest luminosities. Conversely, above z=0.1 we find that luminous IR galaxies (L_IR>10^11 Lsun), the majority of which are cold, dominate the IR luminosity density. We therefore infer that cold galaxies dominate the IR luminosity density across the whole 0<z<1 range, hence appear to be the main driver behind the increase in SFR density up to z~1 whereas local luminous galaxies are not, on the whole, representative of the high redshift population.Comment: 5 pages, 3 figures, accepted for publication in MNRA

Seasonal variation of phytoplankton in My Thanh River, Mekong delta, Vietnam

A study on the seasonal variation of phytoplankton composition was conducted at the upper, middle, and lower parts of the My Thanh River, which supplies an important source of water for aquaculture. Qualitative and quantitative samples of phytoplankton were collected monthly at both high and low tide. The results showed that a total of 171 phytoplankton (algae) species were recorded, belonging to 59 genera and 5 phyla. Diatoms were the most abundant group with the highest species number, followed by green algae. The other phyla possessed a lower number of species. The species composition was more diverse in the rainy season and at high tide at most of the sampling sites. The mean density of algae varied from 30,900-43,521 ind.L^-1^. The density of diatoms was higher in the middle and lower parts. At the same time, euglenoids displayed the highest density in the upper part, showing a difference in the dominant algae group under the influence of salinity. Salinity was found to be significantly positively correlated (p<0.01) with diatoms, whereas it was negatively correlated (p<0.05) with blue-green algae and euglenoids. The algae composition was quite diverse, with the H' index ranging from 2.0-3.3, showing the water quality was slightly to moderately polluted