17,556 research outputs found

    Satisfiability of CTL* with constraints

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    We show that satisfiability for CTL* with equality-, order-, and modulo-constraints over Z is decidable. Previously, decidability was only known for certain fragments of CTL*, e.g., the existential and positive fragments and EF.Comment: To appear at Concur 201

    Quasi-deterministic transport of Brownian particles in an oscillating periodic potential

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    We consider overdamped Brownian dynamics in a periodic potential with temporally oscillating amplitude. We analyze the transport which shows effective diffusion enhanced by the oscillations and derive approximate expressions for the diffusion coefficient. Furthermore we analyze the effect of the oscillating potential on the transport if additionally a constant force is applied. We show the existence of synchronization regimes at which the deterministic dynamics is in resonance with the potential oscillations giving rise to transport with extremely low dispersion. We distinguish slow and fast oscillatory driving and give analytical expressions for the mean velocity and effective diffusion.Comment: submitted: Feb 12th, 201

    Measures of galaxy dust and gas mass with Herschel photometry and prospects for ALMA

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    (Abridged) Combining the deepest Herschel extragalactic surveys (PEP, GOODS-H, HerMES), and Monte Carlo mock catalogs, we explore the robustness of dust mass estimates based on modeling of broad band spectral energy distributions (SEDs) with two popular approaches: Draine & Li (2007, DL07) and a modified black body (MBB). As long as the observed SED extends to at least 160-200 micron in the rest frame, M(dust) can be recovered with a >3 sigma significance and without the occurrence of systematics. An average offset of a factor ~1.5 exists between DL07- and MBB-based dust masses, based on consistent dust properties. At the depth of the deepest Herschel surveys (in the GOODS-S field) it is possible to retrieve dust masses with a S/N>=3 for galaxies on the main sequence of star formation (MS) down to M(stars)~1e10 [M(sun)] up to z~1. At higher redshift (z<=2) the same result is achieved only for objects at the tip of the MS or lying above it. Molecular gas masses, obtained converting M(dust) through the metallicity-dependent gas-to-dust ratio delta(GDR), are consistent with those based on the scaling of depletion time, and on CO spectroscopy. Focusing on CO-detected galaxies at z>1, the delta(GDR) dependence on metallicity is consistent with the local relation. We combine far-IR Herschel data and sub-mm ALMA expected fluxes to study the advantages of a full SED coverage.Comment: Accepted for publication in Astronomy and Astrophysics. Some figures have degraded quality for filesize reason

    CTMC calculations of electron capture and ionization in collisions of multiply charged ions with elliptical Rydberg atoms

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    We have performed classical trajectory Monte Carlo (CTMC) studies of electron capture and ionization in multiply charged (Q=8) ion-Rydberg atom collisions at intermediate impact velocities. Impact parallel to the minor and to the major axis, respectively, of the initial Kepler electron ellipse has been investigated. The important role of the initial electron momentum distribution found for singly charged ion impact is strongly disminished for higher projectile charge, while the initial spatial distribution remains important for all values of Q studied.Comment: 3 pages, 5 figure

    Dietary Folic Acid Needs of High Lean Growth Pigs

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    Twelve sets of five littermate barrows were utilized to determine the folic acid needs of a high lean genetic strain of pigs experiencing a low level of immune system activation. Pigs were penned individually and given ad libitum access to a corn, soybean meal, 27% milk product diet containing dietary concentrations of folic acid equivalent to 100, 200, 300, 400, and 500% of the current NRC (2) estimated requirement for 11 to 22 lb pigs. Pigs were started on test when the average litter weight reached 19 pounds and were taken off test as individual pigs reached a body weight of 51 pounds. Dietary folic acid concentration did not alter daily body weight gain, daily feed intake, feed:gain ratio, or rates of body protein and fat accretion. Based on these data, a dietary folic acid concentration of 0.14 mg per pound of feed is adequate to support optimal growth and body nutrient accretion in high lean growth pigs fed corn-soybean meal-milk product diets from 19 to 51 pounds

    Optical Versus Mid-Infrared Spectroscopic Classification of Ultraluminous Infrared Galaxies

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    The origin of huge infrared luminosities of ultraluminous infrared galaxies (ULIGs) is still in question. Recently, Genzel et al. made mid-infrared (MIR) spectroscopy of a large number of ULIGs and found that the major energy source in them is massive stars formed in the recent starburst activity; i.e., ∌\sim 70% -- 80% of the sample are predominantly powered by the starburst. However, it is known that previous optical spectroscopic observations showed that the majority of ULIGs are classified as Seyferts or LINERs (low-ionization nuclear emission-line regions). In order to reconcile this difference, we compare types of emission-line activity for a sample of ULIGs which have been observed in both optical and MIR. We confirm the results of previous studies that the majority of ULIGs classified as LINERs based on the optical emission-line diagnostics turn to be starburst-dominated galaxies based on the MIR ones. Since the MIR spectroscopy can probe more heavily-reddened, inner parts of the ULIGs, it is quite unlikely that the inner parts are powered by the starburst while the outer parts are powered by non-stellar ionization sources. The most probable resolution of this dilemma is that the optical emission-line nebulae with the LINER properties are powered predominantly by shock heating driven by the superwind activity; i.e., a blast wave driven by a collective effect of a large number of supernovae in the central region of galaxy mergers.Comment: 15 pages, 2 tables, and 3 eps figures. The Astrophysical Journal (Part 1), in pres

    The Signed Roman Domatic Number of a Digraph

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    Let DD be a finite and simple digraph with vertex set V(D)V(D).A {\em signed Roman dominating function} on the digraph DD isa function f:V(D)⟶{−1,1,2}f:V (D)\longrightarrow \{-1, 1, 2\} such that∑u∈N−[v]f(u)≄1\sum_{u\in N^-[v]}f(u)\ge 1 for every v∈V(D)v\in V(D), where N−[v]N^-[v] consists of vv andall inner neighbors of vv, and every vertex u∈V(D)u\in V(D) for which f(u)=−1f(u)=-1 has an innerneighbor vv for which f(v)=2f(v)=2. A set {f1,f2,
,fd}\{f_1,f_2,\ldots,f_d\} of distinct signedRoman dominating functions on DD with the property that ∑i=1dfi(v)≀1\sum_{i=1}^df_i(v)\le 1 for eachv∈V(D)v\in V(D), is called a {\em signed Roman dominating family} (of functions) on DD. The maximumnumber of functions in a signed Roman dominating family on DD is the {\em signed Roman domaticnumber} of DD, denoted by dsR(D)d_{sR}(D). In this paper we initiate the study of signed Romandomatic number in digraphs and we present some sharp bounds for dsR(D)d_{sR}(D). In addition, wedetermine the signed Roman domatic number of some digraphs. Some of our results are extensionsof well-known properties of the signed Roman domatic number of graphs

    Local Swift-BAT active galactic nuclei prefer circumnuclear star formation

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    We use Herschel data to analyze the size of the far-infrared 70micron emission for z<0.06 local samples of 277 hosts of Swift-BAT selected active galactic nuclei (AGN), and 515 comparison galaxies that are not detected by BAT. For modest far-infrared luminosities 8.5<log(LFIR)<10.5, we find large scatter of half light radii Re70 for both populations, but a typical Re70 <~ 1 kpc for the BAT hosts that is only half that of comparison galaxies of same far-infrared luminosity. The result mostly reflects a more compact distribution of star formation (and hence gas) in the AGN hosts, but compact AGN heated dust may contribute in some extremely AGN-dominated systems. Our findings are in support of an AGN-host coevolution where accretion onto the central black hole and star formation are fed from the same gas reservoir, with more efficient black hole feeding if that reservoir is more concentrated. The significant scatter in the far-infrared sizes emphasizes that we are mostly probing spatial scales much larger than those of actual accretion, and that rapid accretion variations can smear the distinction between the AGN and comparison categories. Large samples are hence needed to detect structural differences that favour feeding of the black hole. No size difference AGN host vs. comparison galaxies is observed at higher far-infrared luminosities log(LFIR)>10.5 (star formation rates >~ 6 Msun/yr), possibly because these are typically reached in more compact regions in the first place.Comment: 7 pages, 3 figures, accepted for publication in Astronomy & Astrophysic

    A Compact Starburst Core in the Dusty Lyman Break Galaxy Westphal-MD11

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    Using the IRAM Plateau de Bure Interferometer, we have searched for CO(3-2) emission from the dusty Lyman break galaxy Westphal-MD11 at z = 2.98. Our sensitive upper limit is surprisingly low relative to the system's 850 um flux density and implies a far-IR/CO luminosity ratio as elevated as those seen in local ultraluminous mergers. We conclude that the observed dust emission must originate in a compact structure radiating near its blackbody limit and that a relatively modest molecular gas reservoir must be fuelling an intense nuclear starburst (and/or deeply buried active nucleus) that may have been triggered by a major merger. In this regard, Westphal-MD11 contrasts strikingly with the lensed Lyman break galaxy MS1512-cB58, which is being observed apparently midway through an extended episode of more quiescent disk star formation.Comment: 5 pages, 1 figure (emulateapj), accepted by ApJ
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