Luminous Infrared Galaxies in the Local Universe

We study the morphology and star formation properties of 159 local luminous infrared galaxy (LIRG) using multi-color images from Data Release 2 (DR2) of the Sloan Digital Sky Survey (SDSS). The LIRGs are selected from a cross-correlation analysis between the IRAS survey and SDSS. They are all brighter than 15.9 mag in the r-band and below redshift ~ 0.1, and so can be reliably classified morphologically. We find that the fractions of interacting/merging and spiral galaxies are ~ 48% and ~ 40% respectively. Our results complement and confirm the decline (increase) in the fraction of spiral (interacting/merging) galaxies from z ~1 to z ~ 0.1, as found by Melbourne, Koo & Le Floc'h (2005). About 75% of spiral galaxies in the local LIRGs are barred, indicating that bars may play an important role in triggering star formation rates > 20 M_{sun}/yr in the local universe. Compared with high redshift LIRGs, local LIRGs have lower specific star formation rates, smaller cold gas fractions and a narrower range of stellar masses. Local LIRGs appear to be either merging galaxies forming intermediate mass ellipticals or spiral galaxies undergoing high star formation activities regulated by bars.Comment: 22 pages, 5 figures, accepted for publication in ApJ, title changed, typos corrected,major revisions following referee's comments,updated reference

The Physical Connections Among IR QSOs, PG QSOs and Narrow-Line Seyfert 1 Galaxies

We study the properties of infrared-selected QSOs (IR QSOs), optically-selected QSOs (PG QSOs) and Narrow Line Seyfert 1 galaxies (NLS1s). We compare their properties from the infrared to the optical and examine various correlations among the black hole mass, accretion rate, star formation rate and optical and infrared luminosities. We find that the infrared excess in IR QSOs is mostly in the far infrared, and their infrared spectral indices suggest that the excess emission is from low temperature dust heated by starbursts rather than AGNs. The infrared excess is therefore a useful criterion to separate the relative contributions of starbursts and AGNs. We further find a tight correlation between the star formation rate and the accretion rate of central AGNs for IR QSOs. The ratio of the star formation rate and the accretion rate is about several hundred for IR QSOs, but decreases with the central black hole mass. This shows that the tight correlation between the stellar mass and the central black hole mass is preserved in massive starbursts during violent mergers. We suggest that the higher Eddington ratios of NLS1s and IR QSOs imply that they are in the early stage of evolution toward classical Seyfert 1's and QSOs, respectively.Comment: 32 pages, 6 figures, accepted by Ap

Overcoming the Circular Problem for \gamma-ray Bursts in Cosmological Global Fitting Analysis

Due to the lack of low redshift long Gamma-Ray Bursts (GRBs), the circular problem has been a severe obstacle for using GRBs as cosmological candles. In this paper, we present a new method to deal with such a problem in MCMC global fitting analysis. Assuming that a certain type of correlations between different observables exists in a subsample of GRBs, for the parameters involved in the correlation relation, we treat them as free parameters and determine them simultaneously with cosmological parameters through MCMC analysis on GRB data together with other observational data. Then the circular problem is naturally eliminated in this procedure. We take the Ghirlanda relation as an example while keeping in mind the debate about its physical validity. Together with SNe Ia, WMAP and SDSS data, we include 27 GRBs with the reported Ghirlanda relation in our study, and perform MCMC global fitting. We consider the $\Lambda$CDM model and dynamical dark energy models. In each case, in addition to the constraints on the relevant cosmological parameters, we obtain the best fit values as well as the distributions of the correlation parameters $A$ and $C$. We find that the observational data sets other than GRBs can affect $A$ and $C$ considerably through their degeneracies with the cosmological parameters. The results on $A$ and $C$ for different cosmological models are in well agreement within $1\sigma$ range. The best fit value of $A$ in all models being analyzed is $A\sim 1.53$ with $\sigma \sim 0.08$. For $C$, we have the best value in the range of $0.94-0.98$ with $\sigma\sim 0.1$. It is also noted that the distributions of $A$ and $C$ are generally broader than the priors used in many studies in literature. (Abriged)Comment: 9 pages, 2 figures, 2 tables, Accepted for publication in Ap

Monolithic millimeter-wave diode grid frequency multiplier arrays

Monolithic diode frequency multiplier arrays, including barrier-N-N(+) (BNN) doubler, multi-quantum-barrier-varactor (MQBV) tripler, Schottky-quantum-barrier-varactor (SQBV) tripler, and resonant-tunneling-diode (RTD) tripler arrays, have been successfully fabricated with yields between 85 and 99 percent. Frequency doubling and/or tripling have been observed for all the arrays. Output powers of 2.4-2.6 W (eta = 10-18 percent) at 66 GHz with the BNN doubler and 3.8-10 W (eta = 1.7-4 percent) at 99 GHz with the SQBV tripler have been achieved

LIDAR vs. GEODAS land elevation data in hurricane induced inundation modelling

International audienceLIDAR (Light Detection and Ranging) and GEODAS (GEOphysical DAta System) are respectively taken as the land elevation data for a 3-D storm surge and inundation model to investigate the subsequent inundation differences. Hilton Head, South Carolina, and Croatan-Albemarle-Pamlico Estuary System (CAPES), North Carolina, are the two investigated regions. Significant inundation differences with LIDAR versus GEODAS are found in both regions. The modeled inundation area with GEODAS is larger than with LIDAR. For Category 2?3 hypothetical hurricanes, the maximum inundation difference in Hilton Head region is 67%, while the difference in the CAPES is 156%. Generally, vertical precision difference of the two databases is the major reason for the inundation difference. Recently constructed man-made structures, not included in the GEODAS, but included in the LIDAR data sets may be another contributing reason

mGluR5 antagonism inhibits cocaine reinforcement and relapse by elevation of extracellular glutamate in the nucleus accumbens via a CB1 receptor mechanism.

Metabotropic glutamate receptor 5 (mGluR5) antagonism inhibits cocaine self-administration and reinstatement of drug-seeking behavior. However, the cellular and molecular mechanisms underlying this action are poorly understood. Here we report a presynaptic glutamate/cannabinoid mechanism that may underlie this action. Systemic or intra-nucleus accumbens (NAc) administration of the mGluR5 antagonist 2-methyl-6-(phenylethynyl)-pyridine (MPEP) dose-dependently reduced cocaine (and sucrose) self-administration and cocaine-induced reinstatement of drug-seeking behavior. The reduction in cocaine-taking and cocaine-seeking was associated with a reduction in cocaine-enhanced extracellular glutamate, but not cocaine-enhanced extracellular dopamine (DA) in the NAc. MPEP alone, when administered systemically or locally into the NAc, elevated extracellular glutamate, but not DA. Similarly, the cannabinoid CB1 receptor antagonist, rimonabant, elevated NAc glutamate, not DA. mGluR5s were found mainly in striatal medium-spiny neurons, not in astrocytes, and MPEP-enhanced extracellular glutamate was blocked by a NAc CB1 receptor antagonist or N-type Ca++ channel blocker, suggesting that a retrograde endocannabinoid-signaling mechanism underlies MPEP-induced glutamate release. This interpretation was further supported by our findings that genetic deletion of CB1 receptors in CB1-knockout mice blocked both MPEP-enhanced extracellular glutamate and MPEP-induced reductions in cocaine self-administration. Together, these results indicate that the therapeutic anti-cocaine effects of mGluR5 antagonists are mediated by elevation of extracellular glutamate in the NAc via an endocannabinoid-CB1 receptor disinhibition mechanism

Ferroelectric polarization control of magnetic anisotropy in PbZr0.2Ti0.8O3/La0.8Sr0.2MnO3 heterostructures

The interfacial coupling between the switchable polarization and neighboring magnetic order makes ferroelectric/ferromagnetic composite structures a versatile platform to realize voltage control of magnetic anisotropy. We report the nonvolatile ferroelectric field effect modulation of the magnetocrystalline anisotropy (MCA) in epitaxial PbZr0.2Ti0.8O3 (PZT)/La0.8Sr0.2MnO3 (LSMO) heterostructures grown on (001) SrTiO3 substrates. Planar Hall effect measurements show that the in-plane magnetic anisotropy energy in LSMO is enhanced by about 22% in the hole accumulation state compared to the depletion state, in quantitative agreement with our first-principles density functional theory calculations. Modeling the spin-orbit coupling effect with second-order perturbation theory points to the critical role of the d-orbital occupancy in controlling MCA. Our work provides insights into the effect of ferroelectric polarization on the magnetic anisotropy at the composite multiferroic interfaces, paving the path for their implementation into high-performance, low-power spintronic applications

Probing for cosmological parameters with LAMOST measurement

In this paper we study the sensitivity of the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) project to the determination of cosmological parameters, employing the Monte Carlo Markov Chains (MCMC) method. For comparison, we first analyze the constraints on cosmological parameters from current observational data, including WMAP, SDSS and SN Ia. We then simulate the 3D matter power spectrum data expected from LAMOST, together with the simulated CMB data for PLANCK and the SN Ia from 5-year Supernovae Legacy Survey (SNLS). With the simulated data, we investigate the future improvement on cosmological parameter constraints, emphasizing the role of LAMOST. Our results show the potential of LAMOST in probing for the cosmological parameters, especially in constraining the equation-of-state (EoS) of the dark energy and the neutrino mass.Comment: 7 pages and 3 figures. Replaced with version accepted for publication in JCA

MAGNETO - ELECTRIC LOGIC DEVICES USING SEMICONDUCTOR CHANNEL WITH LARGE SPIN - ORBIT COUPLING

Antiferromagnetic magneto - electric spin - orbit read ( AF SOR ) logic devices are presented . The devices include a voltage - controlled magnetoelectric ( ME ) layer that switches polarization in response to an electric field from the applied voltage and a narrow channel conductor of a spin - orbit coupling ( SOC ) material on the ME layer . One or more sources and one or more drains , each optionally formed of ferromagnetic material , are provided on the SOC material

Building integrated solar thermal (BIST) technologies and their applications: a review of structural design and architectural integration

Solar energy has enormous potential to meet the majority of present world energy demand by effective integration with local building components. One of the most promising technologies is building integrated solar thermal (BIST) technology. This paper presents a review of the available literature covering various types of BIST technologies and their applications in terms of structural design and architectural integration. The review covers detailed description of BIST systems using air, hydraulic (water/heat pipe/refrigerant) and phase changing materials (PCM) as the working medium. The fundamental structure of BIST and the various specific structures of available BIST in the literature are described. Design criteria and practical operation conditions of BIST systems are illustrated. The state of pilot projects is also fully depicted. Current barriers and future development opportunities are therefore concluded. Based on the thorough review, it is clear that BIST is very promising devices with considerable energy saving prospective and building integration feasibility. This review shall facilitate the development of solar driven service for buildings and help the corresponding saving in fossil fuel consumption and the reduction in carbon emission