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Sample records for macho massive compact

  1. A cosmological context for compact massive galaxies

    CERN Document Server

    Stringer, Martin; Vecchia, Claudio Dalla; Martinez-Valpuesta, Inma

    2015-01-01

    To provide a quantitative cosmological context to ongoing observational work on the formation histories and location of compact massive galaxies, we locate and study a sample of exceptionally compact systems in the Bolshoi simulation, using the dark matter structural parameters from a real, compact massive galaxy (NGC1277) as a basis for our working criteria. We find that over 80% of objects in this nominal compact category are substructures of more massive groups or clusters, and that the probability of a given massive substructure being this compact increases significantly with the mass of the host structure; rising to ~30% for the most massive clusters in the simulation. Tracking the main progenitors of this subsample back to z=2, we find them all to be distinct structures with scale radii and densities representative of the population as a whole at this epoch. What does characterise their histories, in addition to mostly becoming substructures, is that they have almost all experienced below-average mass a...

  2. Forming Compact Massive Galaxies at z~2

    CERN Document Server

    van Dokkum, Pieter G; Franx, Marijn; Momcheva, Ivelina; Brammer, Gabriel; Schreiber, Natascha M Forster; Skelton, Rosalind E; Whitaker, Katherine E; van der Wel, Arjen; Bezanson, Rachel; Fumagalli, Mattia; Kriek, Mariska; Leja, Joel; Wuyts, Stijn

    2015-01-01

    In this paper we study a key phase in the formation of massive galaxies: the transition of star forming galaxies into massive (M_stars~10^11 Msun), compact (r_e~1 kpc) quiescent galaxies, which takes place from z~3 to z~1.5. We use HST grism redshifts and extensive photometry in all five 3D-HST/CANDELS fields, more than doubling the area used previously for such studies, and combine these data with Keck MOSFIRE and NIRSPEC spectroscopy. We first confirm that a population of massive, compact, star forming galaxies exists at z~2, using K-band spectroscopy of 25 of these objects at 2.0

  3. How a Star Cluster Ruled Out MACHOs

    Science.gov (United States)

    Kohler, Susanna

    2016-08-01

    Are massive black holes hiding in the halos of galaxies, making up the majority of the universes mysterious dark matter? This possibility may have been ruled out by a star cluster in a small galaxy recently discovered orbiting the Milky Way.Dark Matter CandidatesThe relative amounts of the different constituents of the universe. Dark matter makes up ~27%. [ESA/Planck]Roughly 27% of the mass and energy in the observable universe is made up of dark matter matter invisible to us, which is neither accounted for by observable baryonic matter nor dark energy.What makes up this dark matter? Among the many proposed candidates, one of the least exotic is that of massive compact halo objects, or MACHOs. MACHOs are hypothesized to be black holes that formed in the early universe and now hide in galactic halos. We cant detect light from these objects but their mass adds to the gravitational pull of galaxies.So far, MACHOs prospects arent looking great. They have not been detected in gravitational lensing surveys, ruling out MACHOs between 10-7 and 30 solar masses as the dominant component of dark matter in our galaxy. MACHOs over 100 solar masses have also been ruled out, due to the existence of fragile wide halo binaries that would have been disrupted by the presence of such large black holes.But what about MACHOs between 30 and 100 solar masses? In a new study, Timothy Brandt (NASA Sagan Postdoctoral Fellow at the Institute for Advanced Study, in Princeton, NJ) uses a recently discovered faint galaxy, Eridanus II, to place constraints on MACHOs in this mass range.MACHO constraints from the survival of a star cluster in Eri II, assuming a cluster age of 3 Gyr (a lower bound; constraints increase when assuming an age of 12 Gyr). [Adapted from Brandt 2016]A Star Cluster in Eri IIEridanus II is an ultra-faint dwarf galaxy that lies roughly 1.2 million light-years away from us. This dim object is a satellite galaxy of the Milky Way, discovered as part of the Dark Energy Survey

  4. The fate of high-redshift massive compact galaxies

    CERN Document Server

    de la Rosa, Ignacio G; Ferreras, Ignacio; Almeida, Jorge Sánchez; Vecchia, Claudio Dalla; Martínez-Valpuesta, Inma; Stringer, Martin

    2016-01-01

    Massive high-redshift quiescent compact galaxies (nicknamed red nuggets) have been traditionally connected to present-day elliptical galaxies, often overlooking the relationships that they may have with other galaxy types. We use large bulge-disk decomposition catalogues based on the Sloan Digital Sky Survey (SDSS) to check the hypothesis that red nuggets have survived as compact cores embedded inside the haloes or disks of present-day massive galaxies. In this study, we designate a "compact core" as the bulge component that satisfies a prescribed compactness criterion. Photometric and dynamic mass-size and mass-density relations are used to show that, in the inner regions of galaxies at z ~ 0.1, there are "abundant" compact cores matching the peculiar properties of the red nuggets, an abundance comparable to that of red nuggets at z ~ 1.5. Furthermore, the morphology distribution of the present-day galaxies hosting compact cores is used to demonstrate that, in addition to the standard channel connecting red ...

  5. The Cosmological Quark-Hadron Transition and Massive Compact Halo Objects

    CERN Document Server

    Banerjee, S; Ghosh, S; Raha, S; Sinha, B; Banerjee, Shibaji; Bhattacharyya, Abhijit; Ghosh, Sanjay K.; Raha, Sibaji; Sinha, Bikash

    2000-01-01

    One of the abiding mysteries in the so-called standard cosmological model is the nature of the dark matter. It is universally accepted that there is an abundance of matter in the universe which is non-luminous, due to their very weak interaction, if at all, with the other forms of matter, excepting of course the gravitational attraction. Speculations as to the nature of dark matter are numerous, often bordering on exotics, and searches for such exotic matter is a very active field of astroparticle physics at the dawn of the new century. Nevertheless, in recent years, there has been experimental evidence for at least one form of dark matter - the massive compact halo objects detected through gravitational microlensing effects proposed by Paczynski some years ago. To date, no clear consensus as to what these objects, referred to in the literature as well as in the following by the acronym MACHO, are made of; for a brief discussion of some of the suggestions, see below. In this work, we show that they find a nat...

  6. Can very compact and very massive neutron stars both exist?

    CERN Document Server

    Drago, Alessandro; Pagliara, Giuseppe

    2013-01-01

    The existence of neutron stars with masses of $\\sim 2\\,M_{\\odot}$ requires a stiff equation of state at high densities. On the other hand, the necessary appearance also at high densities of new degrees of freedom, such as hyperons and $\\Delta$ resonances, can lead to a strong softening of the equation of state with resulting maximum masses of $\\sim 1.5\\, M_{\\odot}$ and radii smaller than $\\sim 10$ km. Hints for the existence of compact stellar objects with very small radii have been found in recent statistical analysis of quiescent low-mass X-ray binaries in globular clusters. We propose an interpretation of these two apparently contradicting measurements, large masses and small radii, in terms of two separate families of compact stars: hadronic stars, whose equation of state is soft, can be very compact, while quark stars, whose equation of state is stiff, can be very massive. In this respect an early appearance of $\\Delta$ resonances is crucial to guarantee the stability of the branch of hadronic stars. Our...

  7. A Massive Pulsar in a Compact Relativistic Binary

    CERN Document Server

    Antoniadis, John; Wex, Norbert; Tauris, Thomas M; Lynch, Ryan S; van Kerkwijk, Marten H; Kramer, Michael; Bassa, Cees; Dhillon, Vik S; Driebe, Thomas; Hessels, Jason W T; Kaspi, Victoria M; Kondratiev, Vladislav I; Langer, Norbert; Marsh, Thomas R; McLaughlin, Maura A; Pennucci, Timothy T; Ransom, Scott M; Stairs, Ingrid H; van Leeuwen, Joeri; Verbiest, Joris P W; Whelan, David G; 10.1126/science.1233232

    2013-01-01

    Many physically motivated extensions to general relativity (GR) predict significant deviations in the properties of spacetime surrounding massive neutron stars. We report the measurement of a 2.01 +/- 0.04 solar mass pulsar in a 2.46-hr orbit with a 0.172 +/- 0.003 solar mass white dwarf. The high pulsar mass and the compact orbit make this system a sensitive laboratory of a previously untested strong-field gravity regime. Thus far, the observed orbital decay agrees with GR, supporting its validity even for the extreme conditions present in the system. The resulting constraints on deviations support the use of GR-based templates for ground-based gravitational wave detectors. Additionally, the system strengthens recent constraints on the properties of dense matter and provides insight to binary stellar astrophysics and pulsar recycling.

  8. The compact group--fossil group connection: observations of a massive compact group at z=0.22

    CERN Document Server

    de Oliveira, Claudia L Mendes

    2007-01-01

    It has been suggested that fossil groups could be the cannibalized remains of compact groups, that lost energy through tidal friction. However, in the nearby universe, compact groups which are close to the merging phase and display a wealth of interacting features (such as HCG 31 and HCG 79) have very low velocity dispersions and poor neighborhoods, unlike the massive, cluster-like fossil groups studied to date. In fact, known z=0 compact groups are very seldom embedded in massive enough structures which may have resembled the intergalactic medium of fossil groups. In this paper we study the dynamical properties of CG6, a massive compact group at z=0.220 that has several properties in common with known fossil groups. We report on new g' and i' imaging and multi-slit spectroscopic performed with GMOS on Gemini South. The system has 20 members, within a radius of 1 h_70^-1 Mpc, a velocity dispersion of 700 km/s and has a mass of 1.8 x 10^14 h_70^-1 Msun, similar to that of the most massive fossil groups known. ...

  9. Finite source sizes and the information content of macho-type lens search light curves

    Science.gov (United States)

    Nemiroff, Robert J.; Wickramasinghe, W. A. D. T.

    1994-01-01

    If the dark halo matter is primarily composed of Massive Compact Halo Objects (MACHOs) toward the lower end of the possible detection range (less than 10(exp -3) solar mass) a fraction of the lens detection events should involve the lens crossing directly in front of the disk of the background star. Previously, Nemiroff has shown that each crossing would create an inflection point in the light curve of the MACHO event. Such inflection points would allow a measure of the time it took for the lens to cross the stellar disk. Given an independent estimate of the stellar radius by other methods, one could then obtain a more accurate estimate of the velocity of the lens. This velocity could then, in turn, be used to obtain a more accurate estimate of the mass range for the MACHO or disk star doing the lensing.

  10. Building massive compact planetesimal disks from the accretion of pebbles

    CERN Document Server

    Moriarty, John

    2015-01-01

    We present a model in which planetesimal disks are built from the combination of planetesimal formation and accretion of radially drifting pebbles onto existing planetesimals. In this model, the rate of accretion of pebbles onto planetesimals quickly outpaces the rate of direct planetesimal formation in the inner disk. This allows for the formation of a high mass inner disk without the need for enhanced planetesimal formation or a massive protoplanetary disk. Our proposed mechanism for planetesimal disk growth does not require any special conditions to operate. Consequently, we expect that high mass planetesimal disks form naturally in nearly all systems. The extent of this growth is controlled by the total mass in pebbles that drifts through the inner disk. Anything that reduces the rate or duration of pebble delivery will correspondingly reduce the final mass of the planetesimal disk. Therefore, we expect that low mass stars (with less massive protoplanetary disks), low metallicity stars and stars with gian...

  11. The delayed time distribution of massive double compact star mergers

    CERN Document Server

    Mennekens, N

    2016-01-01

    In order to investigate the temporal evolution of binary populations in general, double compact star binaries and mergers in particular within a galactic evolution context, a most straightforward method is obviously the implementation of a detailed binary evolutionary model in a galactic chemical evolution code. To our knowledge, only the Brussels galactic code explicitly accounts for binaries. With a galactic code that does not explicitly include binaries, the temporal evolution of the population of double compact star binaries and mergers can be estimated with reasonable accuracy if the delayed time distribution (DTD) for these mergers is available. The DTD for supernovae type Ia has been studied extensively the last decade. In the present paper we present the DTD for merging double neutron star binaries and mixed systems consisting of a neutron star and a black hole. The latter mergers are very promising sites for the production of r-process elements and the DTDs can be used to study the galactic evolution...

  12. Towards a census of super-compact massive galaxies in the Kilo Degree Survey

    CERN Document Server

    Tortora, C; Napolitano, N R; Roy, N; Radovich, M; Cavuoti, S; Brescia, M; Longo, G; Getman, F; Capaccioli, M; Grado, L; Kuijken, K H; de Jong, J T A; McFarland, J P

    2015-01-01

    The abundance of compact and massive early-type galaxies (ETGs) can provide significant constraints on the galaxy merging history. The optical Kilo Degree Survey (KiDS), carried out with the VST, gives a unique opportunity to perform a complete census of the most compact galaxies in the Universe. This paper presents a first census of compact galaxy candidates from the first 156 square degrees of KIDS. Effective radii (Re) in the g-, r-, and i- bands are derived fitting galaxy images with PSF-convolved S\\'ersic models, high-quality photo-z, are derived from machine learning techniques, and stellar masses, are calculated by fitting aperture photometry with predictions from stellar population models. After the morphological star/galaxy separation, massiveness ($M_{\\star} > 8 \\times 10^{10}\\, \\rm M_{\\odot}$) and compactness ($R_{e} 0.2, while, remarkably, no such system is found at z<0.2. (abridged)

  13. The diverse evolutionary paths of simulated high-z massive, compact galaxies to z = 0

    Science.gov (United States)

    Wellons, Sarah; Torrey, Paul; Ma, Chung-Pei; Rodriguez-Gomez, Vicente; Pillepich, Annalisa; Nelson, Dylan; Genel, Shy; Vogelsberger, Mark; Hernquist, Lars

    2016-02-01

    Massive quiescent galaxies have much smaller physical sizes at high redshift than today. The strong evolution of galaxy size may be caused by progenitor bias, major and minor mergers, adiabatic expansion, and/or renewed star formation, but it is difficult to test these theories observationally. Herein, we select a sample of 35 massive, compact galaxies (M* = 1-3 × 1011 M⊙, M*/R1.5 > 1010.5 M⊙/kpc1.5) at z = 2 in the cosmological hydrodynamical simulation Illustris and trace them forwards to z = 0 to uncover their evolution and identify their descendants. By z = 0, the original factor of 3 difference in stellar mass spreads to a factor of 20. The dark matter halo masses similarly spread from a factor of 5 to 40. The galaxies' evolutionary paths are diverse: about half acquire an ex situ envelope and are the core of a more massive descendant, a third survive undisturbed and gain very little mass, 15 per cent are consumed in a merger with a more massive galaxy, and a small remainder are thoroughly mixed by major mergers. The galaxies grow in size as well as mass, and only ˜10 per cent remain compact by z = 0. The majority of the size growth is driven by the acquisition of ex situ mass. The most massive galaxies at z = 0 are the most likely to have compact progenitors, but this trend possesses significant dispersion which precludes a direct linkage to compact galaxies at z = 2. The compact galaxies' merger rates are influenced by their z = 2 environments, so that isolated or satellite compact galaxies (which are protected from mergers) are the most likely to survive to the present day.

  14. Binary sdB Stars with Massive Compact Companions

    CERN Document Server

    Geier, S; Edelmann, H; Heber, U; Napiwotzki, R

    2008-01-01

    The masses of compact objects like white dwarfs, neutron stars and black holes are fundamental to astrophysics, but very difficult to measure. We present the results of an analysis of subluminous B (sdB) stars in close binary systems with unseen compact companions to derive their masses and clarify their nature. Radial velocity curves were obtained from time resolved spectroscopy. The atmospheric parameters were determined in a quantitative spectral analysis. Based on high resolution spectra we were able to measure the projected rotational velocity of the stars with high accuracy. In the distribution of projected rotational velocities signs of tidal locking with the companions are visible. By detecting ellipsoidal variations in the lightcurve of an sdB binary we were able to show that subdwarf binaries with orbital periods up to 0.6 d are most likely synchronized. In this case, the inclination angles and companion masses of the binaries can be tightly constrained. Five invisible companions have masses that ar...

  15. M32 Analogs? A Population of Massive Ultra Compact Dwarf Galaxies in intermediate redshift CLASH Clusters

    CERN Document Server

    Zhang, Yuanyuan

    2016-01-01

    We report the discovery of relatively massive, M32-like Ultra Compact Dwarf (UCD) galaxy candidates in $0.2massive galaxy clusters imaged by the CLASH survey. Examining the nearly unresolved objects in the survey, we identify a sample of compact objects concentrated around the brightest cluster galaxies with colors similar to cluster red sequence galaxies. Their colors and magnitudes suggest stellar masses around $10^9 \\mathrm{M_{\\odot}}$. More than half of these galaxies have half-light radii smaller than 200pc, falling into the category of massive Ultra Compact Dwarfs (UCD), with properties similar to M32. The properties are consistent with a tidal stripping origin, but we can not rule out the possibility that they are early-formed compact objects trapped in massive dark matter halos. The 17 CLASH clusters studied in this work on average contain 2.7 of these objects in the their central 0.3 Mpc and 0.6 in their central 50 kpc. Our study demonstrates the possibility of statistically characteriz...

  16. The fate of high redshift massive compact galaxies in dense environments

    Energy Technology Data Exchange (ETDEWEB)

    Kaufmann, Tobias; /Zurich, ETH; Mayer, Lucio; /Zurich U.; Carollo, Marcella; /Zurich, ETH; Feldmann, Robert; /Fermilab /Chicago U., KICP

    2012-01-01

    Massive compact galaxies seem to be more common at high redshift than in the local universe, especially in denser environments. To investigate the fate of such massive galaxies identified at z {approx} 2 we analyse the evolution of their properties in three cosmological hydrodynamical simulations that form virialized galaxy groups of mass {approx} 10{sup 13} M{sub {circle_dot}} hosting a central massive elliptical/S0 galaxy by redshift zero. We find that at redshift {approx} 2 the population of galaxies with M{sub *} > 2 x 10{sup 10} M{sub {circle_dot}} is diverse in terms of mass, velocity dispersion, star formation and effective radius, containing both very compact and relatively extended objects. In each simulation all the compact satellite galaxies have merged into the central galaxy by redshift 0 (with the exception of one simulation where one of such satellite galaxy survives). Satellites of similar mass at z = 0 are all less compact than their high redshift counterparts. They form later than the galaxies in the z = 2 sample and enter the group potential at z < 1, when dynamical friction times are longer than the Hubble time. Also, by z = 0 the central galaxies have increased substantially their characteristic radius via a combination of in situ star formation and mergers. Hence in a group environment descendants of compact galaxies either evolve towards larger sizes or they disappear before the present time as a result of the environment in which they evolve. Since the group-sized halos that we consider are representative of dense environments in the {Lambda}CDM cosmology, we conclude that the majority of high redshift compact massive galaxies do not survive until today as a result of the environment.

  17. Constraints on MACHO Dark Matter from the Star Cluster in the Dwarf Galaxy Eridanus II

    CERN Document Server

    Brandt, Timothy D

    2016-01-01

    I show that a recently discovered star cluster near the center of the ultra-faint dwarf galaxy Eridanus II provides strong constraints on massive compact halo objects (MACHOs) of >~5 M_sun as the main component of dark matter. MACHO dark matter will dynamically heat the cluster, driving it to larger sizes and higher velocity dispersions until it dissolves into its host galaxy. The star cluster has a luminosity of just ~2000 L_sun and is relatively puffy, with a half-light radius of 13 pc, making it much more fragile than other known clusters in dwarf galaxies. For a wide range of plausible dark matter halo properties, Eri II's star cluster combines with existing constraints from microlensing, wide binaries, and disk kinematics to rule out dark matter composed entirely of MACHOs from ~10$^{-7}$ M_sun up to arbitrarily high masses. The cluster in Eri II closes the ~20--100 M_sun window of allowed MACHO dark matter and provides much stronger constraints than wide Galactic binaries for MACHOs of up to thousands o...

  18. On the Origin of the HII Regions Associated with Massive and Compact Superstar Clusters

    Science.gov (United States)

    Silich, Sergiy; Tenorio-Tagle, Guillermo; Muñoz-Tuñón, Casiana

    This contribution to the IV Korea-Mexico meeting deals with the hydrodynamics of the matter reinserted within super star clusters (SSCs) by both stellar winds and supernova explosions, results recently printed in The Astrophysical Journal (Silich et al. 2007). The motivation of such a project arose from the persistent presence of the small mass and compact HII regions that sit right on top of many massive and compact SSCs, from which one expects a large mechanical energy power. The data used for our calculations appear only recently (see Smith et al. 2006) for the massive and compact SSC M82-A1. We presented in our paper the calculated flow, derived through analytical and semi-analytical methods, which led to almost identical results. We have found out that the only way of accommodating a compact HII region (4.5 pc in radius, in the case of M82-A1) on top of a 6.3 Myr old and massive (> 10^6 M_{⊙}) SSC with a half light radius of 3 pc, requires of two assumptions: a very low heating efficiency (Tagle et al. 2007) and a high pressure in the surrounding medium.

  19. A high stellar velocity dispersion for a compact massive galaxy at redshift z = 2.186.

    Science.gov (United States)

    van Dokkum, Pieter G; Kriek, Mariska; Franx, Marijn

    2009-08-06

    Recent studies have found that the oldest and most luminous galaxies in the early Universe are surprisingly compact, having stellar masses similar to present-day elliptical galaxies but much smaller sizes. This finding has attracted considerable attention, as it suggests that massive galaxies have grown in size by a factor of about five over the past ten billion years (10 Gyr). A key test of these results is a determination of the stellar kinematics of one of the compact galaxies: if the sizes of these objects are as extreme as has been claimed, their stars are expected to have much higher velocities than those in present-day galaxies of the same mass. Here we report a measurement of the stellar velocity dispersion of a massive compact galaxy at redshift z = 2.186, corresponding to a look-back time of 10.7 Gyr. The velocity dispersion is very high at km s(-1), consistent with the mass and compactness of the galaxy inferred from photometric data. This would indicate significant recent structural and dynamical evolution of massive galaxies over the past 10 Gyr. The uncertainty in the dispersion was determined from simulations that include the effects of noise and template mismatch. However, we cannot exclude the possibility that some subtle systematic effect may have influenced the analysis, given the low signal-to-noise ratio of our spectrum.

  20. Compact Stellar Systems in the Fornax Cluster Super-massive Star Clusters or Extremely Compact Dwarf Galaxies?

    CERN Document Server

    Drinkwater, M J; Gregg, M D; Phillipps, S

    2000-01-01

    We describe a population of compact objects in the centre of the Fornax Cluster which were discovered as part of our 2dF Fornax Spectroscopic Survey. These objects have spectra typical of old stellar systems, but are unresolved on photographic sky survey plates. They have absolute magnitudes -13compact dwarf galaxies. These objects are all within 30 arcminutes of the central galaxy of the cluster, NGC 1399, but are distributed over larger radii than the globular cluster system of that galaxy. We suggest that these objects are either super-massive star clusters (intra-cluster globular clusters or tidally stripped nuclei of dwarf galaxies) or a new type of low-luminosity compact elliptical dwarf (M32-type) galaxy. The best way to test these hypotheses will be to obtain high resolution imaging and high-dispersion spectroscopy to determine their structures and mass-to-light ratios. This will allow us ...

  1. A new direction for dark matter research: intermediate-mass compact halo objects

    Science.gov (United States)

    Chapline, George F.; Frampton, Paul H.

    2016-11-01

    The failure to find evidence for elementary particles that could serve as the constituents of dark matter brings to mind suggestions that dark matter might consist of massive compact objects (MACHOs). In particular, it has recently been argued that MACHOs with masses > 15Msolar may have been prolifically produced at the onset of the big bang. Although a variety of astrophysical signatures for primordial MACHOs with masses in this range have been discussed in the literature, we favor a strategy that uses the potential for magnification of stars outside our galaxy due to gravitational microlensing of these stars by MACHOs in the halo of our galaxy. We point out that the effect of the motion of the Earth on the shape of the micro-lensing brightening curves provides a promising approach to testing over the course of next several years the hypothesis that dark matter consists of massive compact objects.

  2. Ultra deep sub-kpc view of nearby massive compact galaxies

    CERN Document Server

    Trujillo, Ignacio; Ferre-Mateu, Anna

    2012-01-01

    Using Gemini North telescope ultra deep and high resolution (sub-kpc) K-band adaptive optics imaging of a sample of 4 nearby (z~0.15) massive (~10^{11}M_{sun}) compact (R<1.5 kpc) galaxies, we have explored the structural properties of these rare objects with an unprecedented detail. Our surface brightness profiles expand over 12 magnitudes in range, allowing us to explore the presence of any faint extended envelope on these objects down to stellar mass densities ~10^{6} M_{sun}/kpc^{2} at radial distances of ~15 kpc. We find no evidence for any extended faint tail altering the compactness of these galaxies. Our objects are elongated, resembling visually S0 galaxies and have a central stellar mass density well above the stellar mass densities of objects with similar stellar mass but normal size in the present universe. If these massive compact objects will eventually transform into normal size galaxies, the processes driving this size growth will have to migrate around 2-3x10^{10}M_{sun} stellar mass from ...

  3. The MACHO project 2nd year LMC microlensing results and dark matter implications

    CERN Document Server

    Pratt, M R; Allsman, R A; Alves, D R; Axelrod, T S; Becker, A C; Bennett, D P; Cook, K H; Freeman, K C; Griest, K; Guern, J A; Lehner, M J; Marshall, S L; Peterson, B A; Quinn, P J; Rodgers, A W; Stubbs, C W; Sutherland, W; Welch, D L

    1996-01-01

    The MACHO Project is searching for galactic dark matter in the form of massive compact halo objects (Machos). Millions of stars in the Large Magellanic Cloud (LMC), Small Magellanic Cloud (SMC), and Galactic bulge are photometrically monitored in an attempt to detect rare gravitational microlensing events caused by otherwise invisible Machos. Analysis of two years of photometry on 8.5 million stars in the LMC reveals 8 candidate microlensing events, far more than the \\sim1 event expected from lensing by low-mass stars in known galactic populations. From these eight events we estimate the optical depth towards the LMC from events with 2 < \\that < 200 days to be \\tau_2^{200} \\approx 2.9 ^{+1.4}_{-0.9} \\ten{-7}. This exceeds the optical depth of 0.5\\ten{-7} expected from known stars and is to be compared with an optical depth of 4.7\\ten{-7} predicted for a ``standard'' halo composed entirely of Machos. The total mass in this lensing population is \\approx 2^{+1.2}_{-0.7} \\ten{11} \\msun (within 50 kpc from t...

  4. Compact E+A Galaxies as a Progenitor of Massive Compact Quiescent Galaxies at 0.2

    CERN Document Server

    Zahid, H Jabran; Geller, Margaret J; Damjanov, Ivana; Chillingarian, Igor; Sohn, Jubee; Salmi, Fadia; Hwang, Ho Seong

    2016-01-01

    We search the Sloan Digital Sky Survey and the Baryon Oscillation Sky Survey to identify ~5500 massive compact quiescent galaxy candidates at 0.2compact E+A galaxies suggest that they are a progenitor of massive compact quiescent galaxies. Thus, two separate classes of objects-compact E+A and compact quiescent galaxies-may be linked by a common evolutionary sequence. The typical stellar population age of compact E+A galaxies is <1 Gyr. The existence of compact E+A galaxies with young stellar populations at 0.2compact quiescent galaxies first appear at intermediate redshifts. We derive a lower limit for the number density of compact E+A galaxies. Assuming passive evolution, we convert this number density into an app...

  5. The diverse evolutionary paths of simulated high-$z$ massive, compact galaxies to $z = 0$

    CERN Document Server

    Wellons, Sarah; Ma, Chung-Pei; Rodriguez-Gomez, Vicente; Pillepich, Annalisa; Nelson, Dylan; Genel, Shy; Vogelsberger, Mark; Hernquist, Lars

    2015-01-01

    Massive quiescent galaxies at high redshift have been observed to have much smaller physical sizes than their local counterparts. Several mechanisms have been invoked to explain the strong evolution of galaxy size with redshift, including progenitor bias, major and minor mergers, adiabatic expansion, and renewed star formation. However, it is difficult to connect galaxy populations between cosmological epochs to test these theories observationally. Herein, we select a sample of 35 massive, compact galaxies ($M_*$ = 1-3 x $10^{11}$ M$_\\odot$, $M_*/R^{1.5}$ > $10^{10.5}$ M$_\\odot$/kpc$^{1.5}$) at z=2 in the cosmological hydrodynamical simulation Illustris and trace them forward to z=0 to uncover how they evolve to the present day. By z=0, the original factor of 3 difference in stellar mass has spread to a factor of 20. The spread in dark matter halo mass similarly increases from a factor of 5 to a factor of 40. The compact galaxies' evolutionary paths are diverse: about half acquire an ex-situ envelope and exis...

  6. A new direction for dark matter research: intermediate mass compact halo objects

    CERN Document Server

    Axelrod, T; Dawson, W; Frampton, P H

    2016-01-01

    The failure to find evidence for elementary particles that could serve as the constituents of dark matter brings to mind suggestions that dark matter might consist of massive compact objects (MACHOs). In particular, it has recently been argued that MACHOs with masses > 15 solar masses may have been prolifically produced at the onset of the big bang. Although a variety of astrophysical signatures for primordial MACHOs with masses in this range have been discussed in the literature, we favor a strategy that uses the potential for gravitational microlensing of stars outside our galaxy to directly detect the presence of MACHOs in the halo of our galaxy. We point out that the effect of the motion of the Earth on the shape of the microlensing brightening curves provides a promising approach to confirming over the course of next several years that dark matter consists of MACHOs.

  7. Secular evolution of compact binaries near massive black holes: Gravitational wave sources and other exotica

    CERN Document Server

    Antonini, Fabio

    2012-01-01

    The environment near super massive black holes (SMBHs) in galactic nuclei contain a large number of stars and compact objects. A fraction of these are likely to be members of binaries. Here we discuss the binary population of stellar black holes and neutron stars near SMBHs and focus on the secular evolution of such binaries, due to the perturbation by the SMBH. Binaries with highly inclined orbits in respect to their orbit around the SMBH are strongly affected by secular Kozai processes, which periodically change their eccentricities and inclinations (Kozai-cycles). During periapsis approach, at the highest eccentricities during the Kozai-cycles, gravitational wave emission becomes highly efficient. Some binaries in this environment can inspiral and coalesce at timescales much shorter than a Hubble time and much shorter than similar binaries which do not reside near a SMBH. The close environment of SMBHs could therefore serve as catalyst for the inspiral and coalescence of binaries, and strongly affect their...

  8. On the Extreme Positive Feedback Star-Forming Mode from Massive and Compact Superstar Clusters

    CERN Document Server

    Tenorio-Tagle, G; Munoz-Tunon, A R; Tenorio-Tagle, Guillermo; Silich, Sergiy; Munoz-Tunon, Ary Rodriguez Gonzalez & Casiana

    2005-01-01

    The force of gravity acting within the volume occupied by young, compact and massive superstar clusters, is here shown to drive in situ all the matter deposited by winds and supernovae into several generations of star formation. These events are promoted by radiative cooling which drains the thermal energy of the ejected gas causing its accumulation to then rapidly exceed the gravitational instability criterion. A detailed account of the integrated ionizing radiation and mechanical luminosity as a function of time is here shown to lead to a new stationary solution. In this, the mass deposition rate $\\dot M$, instead of causing a wind as in the adiabatic solution, turns into a positive feedback star-forming mode equal to the star formation rate. Some of the implications of this extreme positive feedback mode are discussed.

  9. An over-massive black hole in the compact lenticular galaxy NGC 1277.

    Science.gov (United States)

    van den Bosch, Remco C E; Gebhardt, Karl; Gültekin, Kayhan; van de Ven, Glenn; van der Wel, Arjen; Walsh, Jonelle L

    2012-11-29

    Most massive galaxies have supermassive black holes at their centres, and the masses of the black holes are believed to correlate with properties of the host-galaxy bulge component. Several explanations have been proposed for the existence of these locally established empirical relationships, including the non-causal, statistical process of galaxy-galaxy merging, direct feedback between the black hole and its host galaxy, and galaxy-galaxy merging and the subsequent violent relaxation and dissipation. The empirical scaling relations are therefore important for distinguishing between various theoretical models of galaxy evolution, and they furthermore form the basis for all black-hole mass measurements at large distances. Observations have shown that the mass of the black hole is typically 0.1 per cent of the mass of the stellar bulge of the galaxy. Until now, the galaxy with the largest known fraction of its mass in its central black hole (11 per cent) was the small galaxy NGC 4486B. Here we report observations of the stellar kinematics of NGC 1277, which is a compact, lenticular galaxy with a mass of 1.2 × 10(11) solar masses. From the data, we determine that the mass of the central black hole is 1.7 × 10(10) solar masses, or 59 per cent of its bulge mass. We also show observations of five other compact galaxies that have properties similar to NGC 1277 and therefore may also contain over-massive black holes. It is not yet known if these galaxies represent a tail of a distribution, or if disk-dominated galaxies fail to follow the usual black-hole mass scaling relations.

  10. The Most Massive Ultra-Compact Dwarf Galaxy in the Virgo Cluster

    CERN Document Server

    Liu, Chengze; Toloba, Elisa; Mihos, J Christopher; Ferrarese, Laura; Alamo-Martínez, Karla; Zhang, Hong-Xin; Côté, Patrick; Cuillandre, Jean-Charles; Cunningham, Emily C; Guhathakurta, Puragra; Gwyn, Stephen; Herczeg, Gregory; Lim, Sungsoon; Puzia, Thomas H; Roediger, Joel; Sánchez-Janssen, Rubén; Yin, Jun

    2015-01-01

    We report on the properties of the most massive ultra-compact dwarf galaxy (UCD) in the nearby Virgo Cluster of galaxies using imaging from the Next Generation Virgo Cluster Survey (NGVS) and spectroscopy from Keck/DEIMOS. This object (M59-UCD3) appears to be associated with the massive Virgo galaxy M59 (NGC 4621), has an integrated velocity dispersion of 78 km/s, a dynamical mass of $3.7\\times10^8 M_\\odot$, and an effective radius ($R_e$) of 25 pc. With an effective surface mass density of $9.4\\times10^{10} M_\\odot/kpc^2$, it is the densest galaxy in the local Universe discovered to date, surpassing the density of the luminous Virgo UCD, M60-UCD1. M59-UCD3 has a total luminosity of $M_{g'}=-14.2$ mag, and a spectral energy distribution consistent with an old (14 Gyr) stellar population with [Fe/H]=0.0 and [$\\alpha$/Fe]=+0.2. We also examine deep imaging around M59 and find a broad low surface brightness stream pointing towards M59-UCD3, which may represent a tidal remnant of the UCD progenitor. This UCD, alo...

  11. Compact High-Redshift Galaxies Are the Cores of Present-Day Massive Spheroids

    CERN Document Server

    Hopkins, Philip F; Murray, Norman; Quataert, Eliot; Lauer, Tod; Ma, Chung-Pei

    2009-01-01

    Observations suggest that effective radii of high-z massive spheroids are as much as a factor ~6 smaller than low-z galaxies of comparable mass. Given the apparent absence of low-z counterparts, this has often been interpreted as indicating that the high density, compact red galaxies must be 'puffed up' by some mechanism. We compare the ensemble of high-z observations with large samples of well-observed low-z ellipticals. At the same physical radii, the stellar surface mass densities of low and high-z systems are comparable. Moreover, the abundance of high surface density material at low redshift is comparable to or larger than that observed at z>1-2, consistent with the continuous buildup of spheroids over this time. The entire population of compact, high-z red galaxies may be the progenitors of the high-density cores of present-day ellipticals, with no need for a decrease in stellar density from z=2 to z=0. The primary difference between low and high-z systems is thus the observed low-density material at la...

  12. POINT-AGAPE Pixel Lensing Survey of M31 Evidence for a MACHO contribution to Galactic Halos

    CERN Document Server

    Novati, S C; An, J; Baillon, Paul; Belokurov, V; Carr, B J; Creze, M; Evans, N W; Giraud-Héraud, Yannick; Gould, A; Jetzer, P; Kaplan, J; Kerins, E; Hewett, P C; Smartt, S J; Stalin, C S; Tsapras, Y; Weston, M J; Jetzer, Ph.

    2005-01-01

    The POINT-AGAPE collaboration is carrying out a search for gravitational microlensing toward M31 to reveal galactic dark matter in the form of MACHOs (Massive Astrophysical Compact Halo Objects) in the halos of the Milky Way and M31. A high-threshold analysis of 3 years of data yields 6 bright, short--duration microlensing events, which are confronted to a simulation of the observations and the analysis. The observed signal is much larger than expected from self lensing alone and we conclude, at the 95% confidence level, that at least 20% of the halo mass in the direction of M31 must be in the form of MACHOs if their average mass lies in the range 0.5-1 M$_\\odot$. This lower bound drops to 8% for MACHOs with masses $\\sim 0.01$ M$_\\odot$. In addition, we discuss a likely binary microlensing candidate with caustic crossing. Its location, some 32' away from the centre of M31, supports our conclusion that we are detecting a MACHO signal in the direction of M31.

  13. What Are the Progenitors of Compact, Massive, Quiescent Galaxies at z=2.3? The Population of Massive Galaxies at z>3 from NMBS and CANDELS

    CERN Document Server

    Stefanon, Mauro; Rudnick, Gregory H; Brammer, Gabriel B; Whitaker, Katherine E

    2013-01-01

    [Abridged] Using public data from the NMBS and CANDELS surveys, we study the population of massive galaxies at z>3 to identify the potential progenitors of z~2 compact, massive, quiescent (CMQ) galaxies, furthering our understanding of the evolution of massive galaxies. Our work is enabled by high-resolution CANDELS images and accurate photometric redshifts, stellar masses and star formation rates (SFRs) from 37-band NMBS photometry. The total number of z>3 massive galaxies is consistent with the number of massive quiescent (MQ) galaxies at z~2, implying that the SFRs for all of these galaxies must be much lower by z~2. We discover 4 CMQ galaxies at z>3, pushing back the time for which such galaxies have been observed. However, the volume density for these galaxies is significantly less than that of galaxies at z10^(10.6)Msun, likely to become members of the CMQ galaxy population at z~2. We evolve the stellar masses and SFRs of each individual z>3 galaxy adopting 5 different star formation histories (SFHs) an...

  14. Gravitational radiation from compact binary systems in the massive Brans-Dicke theory of gravity

    CERN Document Server

    Alsing, Justin; Will, Clifford; Zaglauer, Helmut

    2011-01-01

    We derive the equations of motion, the periastron shift, and the gravitational radiation damping for quasicircular compact binaries in a massive variant of the Brans-Dicke theory of gravity. We also study the Shapiro time delay and the Nordtvedt effect in this theory. By comparing with recent observational data, we put bounds on the two parameters of the theory: the Brans-Dicke coupling parameter \\omega_{BD} and the scalar mass m_s. We find that the most stringent bounds come from Cassini measurements of the Shapiro time delay in the Solar System, that yield a lower bound \\omega_{BD}>40000 for scalar masses m_s1000 for m_s1250 for m_s<10^{-20} eV. A first estimate suggests that bounds comparable to the Shapiro time delay may come from observations of radiation damping in the eccentric white dwarf-neutron star binary PSR J1141-6545, but a quantitative prediction requires the extension of our work to eccentric orbits.

  15. Early formation of massive, compact, spheroidal galaxies with classical profiles by violent disc instability or mergers

    CERN Document Server

    Ceverino, Daniel; Tweed, Dylan; Primack, Joel

    2014-01-01

    We address the formation of massive stellar spheroids between redshifts $z=4$ and 1 using a suite of AMR hydro-cosmological simulations. The spheroids form as bulges, and the spheroid mass growth is partly driven by violent disc instability (VDI) and partly by mergers. A kinematic decomposition to disc and spheroid yields that the mass fraction in the spheroid is between 50% and 90% and is roughly constant in time, consistent with a cosmological steady state of VDI discs that are continuously fed from the cosmic web. The density profile of the spheroid is typically classical, with a Sersic index $n = 4.5\\pm 1$, independent of whether it grew by mergers or VDI. The disc is characterized by $n=1.5\\pm 0.5$, and the whole galaxy by $n=3\\pm 1$. The high-redshift spheroids are compact due to the dissipative inflow of gas and the high universal density. The stellar surface density within the effective radius of each galaxy as it evolves remains roughly constant in time after its first growth. For galaxies of a fixed...

  16. The MACHO data pipeline

    CERN Document Server

    Axelrod, T S; Quinn, P J; Bennett, D P; Freeman, K C; Peterson, B A; Rodgers, A W; Alcock, C B; Cook, K H; Griest, K; Marshall, S L; Pratt, M R; Stubbs, C W; Sutherland, W

    1995-01-01

    The MACHO experiment is searching for dark matter in the halo of the Galaxy by monitoring more than 20 million stars in the LMC and Galactic bulge for gravitational microlensing events. The hardware consists of a 50 inch telescope, a two-color 32 megapixel ccd camera, and a network of computers. On clear nights the system generates up to 8 GB of raw data and 1 GB of reduced data. The computer system is responsible for all realtime control tasks, for data reduction, and for storing all data associated with each observation in a data base. The subject of this paper is the software system that handles these functions. It is an integrated system controlled by Petri nets that consists of multiple processes communicating via mailboxes and a bulletin board. The system is highly automated, readily extensible, and incorporates flexible error recovery capabilities. It is implemented with C++ in a Unix environment.

  17. The Morphologies of Massive Galaxies at 1Compact Bulges, and the Rise and Fall of Massive Disks

    CERN Document Server

    Bruce, V A; Cirasuolo, M; McLure, R J; Targett, T A; Bell, E F; Croton, D J; Dekel, A; Faber, S M; Ferguson, H C; Grogin, N A; Kocevski, D D; Koekemoer, A M; Koo, D C; Lai, K; Lotz, J M; McGrath, E J; Newman, J A; van der Wel, A

    2012-01-01

    We have used deep, HST, near-IR imaging to study the morphological properties of the most massive galaxies at high z, modelling the WFC3/IR H-band images of the ~200 galaxies in the CANDELS-UDS field with 1 10^11 M_sun. We have used both single-Sersic and bulge+disk models, have investigated the errors/biases introduced by uncertainties in the background and the PSF, and have obtained formally-acceptable model fits to >90% of the galaxies. Our results indicate that these massive galaxies at 1 2 the compact bulges display effective radii a factor ~4 smaller than local ellipticals of comparable mass. These trends appear to extend to the bulge components of disk-dominated galaxies, and vice versa. We also find that, while such massive galaxies at low z are bulge-dominated, at 1 2 they are mostly disk-dominated. The majority of the disk-dominated galaxies are actively forming stars, but this is also true for many of the bulge-dominated systems. Interestingly, however, while most of the quiescent galaxies are b...

  18. The fate of a red nugget: In-situ star formation of satellites around a massive compact galaxy

    CERN Document Server

    Morishita, Takahiro

    2015-01-01

    To study the accretion phase for local massive galaxies, we search accreting satellites around a massive compact galaxy (M_*~3.9x10^10Msun), spectroscopically confirmed (z_spec-1.9213) in the eXtreme Deep Field, which has been originally reported in Szomoru et al. We detect 1369 satellite candidates within the projected virial radius (rvir~300 kpc) of the compact galaxy in the all-combined ACS image with 5sigma-limiting magnitude of mACS~30.6 ABmag, which corresponds to ~1.6x10^7M_sun at the redshift. The photometric redshift measured with 12 multi-band images confirms 34 satellites out of the candidates. Most of the satellites are found to have the rest-frame colors consistent with star forming galaxies. We investigate the relation between stellar mass and star formation rate (the star formation main sequence), and find the steeper slope at the low-mass end (<10^8M_sun), while more massive satellites are consistently on the sequence reported in previous studies. Within the uncertainties of star formation ...

  19. QSO Selection Algorithm Using Time Variability and Machine Learning: Selection of 1,620 QSO Candidates from MACHO LMC Database

    CERN Document Server

    Kim, Dae-Won; Byun, Yong-Ik; Alcock, Charles; Khardon, Roni

    2011-01-01

    We present a new QSO selection algorithm using a Support Vector Machine (SVM), a supervised classification method, on a set of extracted times series features including period, amplitude, color, and autocorrelation value. We train a model that separates QSOs from variable stars, non-variable stars and microlensing events using 58 known QSOs, 1,629 variable stars and 4,288 non-variables using the MAssive Compact Halo Object (MACHO) database as a training set. To estimate the efficiency and the accuracy of the model, we perform a cross-validation test using the training set. The test shows that the model correctly identifies ~80% of known QSOs with a 25% false positive rate. The majority of the false positives are Be stars. We applied the trained model to the MACHO Large Magellanic Cloud (LMC) dataset, which consists of 40 million lightcurves, and found 1,620 QSO candidates. During the selection none of the 33,242 known MACHO variables were misclassified as QSO candidates. In order to estimate the true false po...

  20. Disky elliptical galaxies and the allegedly over-massive black hole in the compact massive `ES' galaxy NGC 1271

    CERN Document Server

    Graham, Alister W; Savorgnan, Giulia A D

    2016-01-01

    While spiral and lenticular galaxies have large-scale disks extending beyond their bulges, and most local early-type galaxies with 10^{10} < M_*/M_Sun < 2x10^{11} contain a disk (e.g., ATLAS^3D), the early-type galaxies do possess a range of disk sizes. The edge-on, `intermediate-scale' disk in the `disky elliptical' galaxy NGC 1271 has led to some uncertainty as to what is its spheroidal component. Walsh et al. reported a directly measured black hole mass of 3x10^9 M_Sun for this galaxy; which they remarked was an order of magnitude greater than what they expected based on their derivation of the host spheroid's luminosity. Our near-infrared image analysis supports a small embedded disk within a massive spheroidal component with M_{sph,*} = (0.9+/-0.2)x10^{11} M_Sun (using M_*/L_H = 1.4 from Walsh et al.). This places NGC 1271 just 1.6-sigma above the near-linear M_bh-M_{sph,*} relation for early-type galaxies. Therefore, past speculation that there may be a systematic difference in the black hole scal...

  1. Deep Chandra Observations of the Compact Starburst Galaxy Henize 2-10: X-rays from the Massive Black Hole

    CERN Document Server

    Reines, Amy; Miller, Jon; Sivakoff, Gregory; Greene, Jenny; Hickox, Ryan; Johnson, Kelsey

    2016-01-01

    We present follow-up X-ray observations of the candidate massive black hole (BH) in the nucleus of the low-mass, compact starburst galaxy Henize 2-10. Using new high-resolution observations from the Chandra X-ray Observatory totaling 200 ks in duration, as well as archival Chandra observations from 2001, we demonstrate the presence of a previously unidentified X-ray point source that is spatially coincident with the known nuclear radio source in Henize 2-10 (i.e., the massive BH). We show that the hard X-ray emission previously identified in the 2001 observation is dominated by a source that is distinct from the nucleus, with the properties expected for a high-mass X-ray binary. The X-ray luminosity of the nuclear source suggests the massive BH is radiating significantly below its Eddington limit (~10^-6 L_Edd), and the soft spectrum resembles other weakly accreting massive BHs including Sagittarius A*. Analysis of the X-ray light curve of the nucleus reveals the tentative detection of a ~9-hour periodicity, ...

  2. Gravitational Waves Notes, Issue #5 : "The Capra research programme for capture of small compact objects by massive black holes"

    CERN Document Server

    Amaro-Seoane, Pau; Thornburg, Jonathan

    2011-01-01

    GW Notes was born from the need for a journal where the distinct communities involved in gravitation wave research might gather. While these three communities - astrophysics, general relativity and data analysis - have made significant collaborative progress over recent years, we believe that it is indispensable to future advancement that they draw closer, and that they speak a common idiom. In this 6th GW Note (since we started numbering with #0), we present the work of Jonathan Thornburg, who has been fully-refereed, on the Capra research programme for capture of small compact objects by massive black holes.

  3. The Majority of Compact Massive Galaxies at z~2 are Disk Dominated

    CERN Document Server

    van der Wel, Arjen; Wuyts, Stijn; McGrath, Elizabeth J; Koekemoer, Anton M; Bell, Eric F; Holden, Bradford P; Robaina, Aday R; McIntosh, Daniel H

    2011-01-01

    We investigate the stellar structure of massive, quiescent galaxies at z~2, based on HST/WFC3 imaging from the Early Release Science program. Our sample of 14 galaxies has stellar masses of M* > 10^{10.8} Msol and photometric redshifts of 1.5 < z < 2.5. In agreement with previous work, their half-light radii are <2 kpc, much smaller than equally massive galaxies in the present-day universe. A significant subset of the sample appear highly flattened in projection, which implies, considering viewing angle statistics, that a significant fraction of the galaxies in our sample have pronounced disks. This is corroborated by two-dimensional surface brightness profile fits. We estimate that 65% +/- 15% of the population of massive, quiescent z~2 galaxies are disk-dominated. The median disk scale length is 1.5 kpc, substantially smaller than the disks of equally massive galaxies in the present-day universe. Our results provide strong observational evidence that the much-discussed ultra-dense high-redshift gal...

  4. Massive Stars and Their Compact Remnants in High-Mass X-Ray Binaries

    NARCIS (Netherlands)

    Kaper, L.; van der Meer, A.

    2007-01-01

    In a high-mass X-ray binary (HMXB) a massive star interacts with a neutron-star or black-hole companion in various ways. The gravitational interaction enables the measurement of fundamental parameters such as the mass of both binary components, providing important constraints on the evolutionary his

  5. Priming Macho Attitudes and Emotions.

    Science.gov (United States)

    Beaver, Erik D.; And Others

    1992-01-01

    Investigated the effects of reading one of four priming stimuli stories (control, consenting sex, rape, or family) on males' evaluations of, and emotional reactions to, two videotaped date-rape scenarios. Results supported the concepts of a macho personality and revealed interactive effects for both the rape and family prime. (RJM)

  6. Producción masiva y simultánea de machos de Ceratitis capitata (Diptera: Tephritidae y parasitoides Dichasmimorpha longicaudata (Hymenoptera: Braconidae Massive and simultaneous production of Ceratitis capitata (Diptera: Tephritidae males and Diachasmimorpha longicaudata (Hymenoptera: Braconidae parasitoids

    Directory of Open Access Journals (Sweden)

    Silvia N. López

    2006-12-01

    Full Text Available En la línea de sexado genético «Cast191» las hembras de Ceratitis capitata son homocigotas para el gen slow , lo que reduce su velocidad de desarrollo; los machos son heterocigotas y muestran una velocidad de desarrollo normal. Esta característica permitió producir, con Cast191, machos estériles por un lado, y parasitoides criados sobre las larvas remanentes por el otro. Nuestro objetivo con este trabajo fue producir ambos insumos simultáneamente y a una escala mayor que hasta ahora. Además, bajo estas condiciones, y en un intento por aumentar la separación entre sexos, se aplicó a las larvas del primer estadío un pulso de 15º C, durante 1 ó 2 días, luego del cual se las mantuvo a 20º C ó 25º C, hasta que entraron al estado de pupa, luego se mantuvo todo el material a 25º C. La mejor separación de sexos, lograda con el tratamiento a 20º C sin pulso de frío, se usó para comparar la calidad del parasitoide Diachasmimorpha longicaudata, criado sobre las larvas obtenidas tras la separación de los machos, con aquellos criados sobre la línea salvaje. Para ello, este tratamiento de separación fue aplicado en la cría de la mosca, y el material remanente de dieta con larvas fue expuesto al parasitoide. La tasa de parasitismo obtenida fue semejante a la hallada sobre la línea salvaje, y la tasa sexual de la F 1 del parasitoide presentó un sesgo hacia las hembras aún mayor. Se discute la factibilidad de utilizar la línea Cast191 de C. Capitata, para la producción a mayor escala de machos de mosca y para la cría masiva del parasitoide D. longicaudata.In the genetic sexing strain «Cast191», the females of Ceratitis capitata are homozygous for the mutation slow , slowing down their rate of development, and the males are heterozygous, having a normal rate of development. This feature made Cast191 capable of producing sterile males, on one hand, and parasitoids that are reared on the remaining larvae, on the other. The

  7. Size Evolution of Early-Type Galaxies and Massive Compact Objects as the Dark Matter

    CERN Document Server

    Totani, Tomonori

    2009-01-01

    The dramatic size evolution of early-type galaxies from z ~ 2 to 0 poses a new challenge in the theory of galaxy formation, which may not be explained by the standard picture. It is shown here that the size evolution can be explained if the non-baryonic cold dark matter is composed of compact objects having a mass scale of ~10^5 M_sun. This form of dark matter is consistent with or only weakly constrained by the currently available observations. The kinetic energy of the dark compact objects is transferred to stars by dynamical friction, and stars around the effective radius are pushed out to larger radii, resulting in a pure size evolution. This scenario has several good properties to explain the observations, including the ubiquitous nature of size evolution and faster disappearance of higher density galaxies.

  8. HerMES : SPIRE detection of high redshift massive compact galaxies in GOODS-N field

    CERN Document Server

    Cava, A; Perez-Fournon, I; Buitrago, F; Trujillo, I; Altieri, B; Amblard, A; Auld, R; Bock, J; Brisbin, D; Burgarella, D; Castro-Rodriguez, N; Chanial, P; Cirasuolo, M; Clements, D L; Conselice, C J; Cooray, A; Eales, S; Elbaz, D; Ferrero, P; Franceschini, A; Glenn, J; Solares, E A Gonzalez; Griffin, M; Ibar, E; Ivison, R J; Marchetti, L; Morrison, G E; Mortier, A M J; Oliver, S J; Page, M J; Papageorgiou, A; Pearson, C P; Pohlen, M; Rawlings, J I; Raymond, G; Rigopoulou, D; Roseboom, I G; Rowan-Robinson, M; Scott, D; Seymour, N; Smith, A J; Symeonidis, M; Tugwell, K E; Vaccari, M; Valtchanov, I; Vieira, J D; Vigroux, L; Wang, L; Wright, G

    2010-01-01

    We have analysed the rest-frame far infrared (FIR) properties of a sample of massive (Mstar > 10^11Msun) galaxies at 2massive galaxies with structural parameters characterised with HST NICMOS-3. We study detections at submm Herschel bands, together with Spitzer 24{\\mu}m data, as a function of the morphological type, mass and size. We find that 26/45 sources are detected at MIPS-24{\\mu}m and 15/45 (all MIPS-24{\\mu}m detections) are detected at SPIRE-250{\\mu}m, with disk-like galaxies more easily detected. We derive star formation rates (SFR) and specific star formation rates (sSFR) by fitting the spectral energy distribution (SED) of our sources, taking into account non-detections for SPIRE and syst...

  9. Unveiling a Compact Cluster of Massive and Young Stars in IRAS 17233-3606

    CERN Document Server

    Zapata, Luis A; Menten, Karl M; Schilke, Peter; Rolffs, Rainer; Hieret, Carolin

    2008-01-01

    We have analyzed sensitive high spatial resolution archival radio continuum data at 1.3, 2.0, 3.6 and 6.0 cm as well as the H2O maser molecular line data obtained using the Very Large Array (VLA) in its hybrid AB configuration toward the high-mass star-forming region IRAS 17233-3606 (G351.78-0.54). We find nine compact radio sources associated with this region, six of them are new radio detections. We discuss the characteristics of these sources based mostly on their spectral indices and find that most of them appear to be optically thin or thick ultra- and hyper-compact HII regions ionized by B ZAMS stars. Furthermore, in a few cases the radio emission may arise from optically thick dusty disks and/or cores, however more observations at different wavelengths are necessity to firmly confirm their true nature. In addition, we compared our centimeter maps with the mid-infrared images fromthe Spitzer Space Observatory GLIMPSE survey revealing a cluster of young protostars in the region together with multiple col...

  10. NGC 1277: A MASSIVE COMPACT RELIC GALAXY IN THE NEARBY UNIVERSE

    Energy Technology Data Exchange (ETDEWEB)

    Trujillo, Ignacio; Vazdekis, Alexandre [Instituto de Astrofísica de Canarias, c/Vía Láctea s/n, E-38205-La Laguna, Tenerife (Spain); Ferré-Mateu, Anna [Subaru Telescope, 650 North A' ohoku Place, Hilo, HI 96720 (United States); Balcells, Marc [Isaac Newton Group of Telescopes, E-38700 Santa Cruz de La Palma, Canary Islands (Spain); Sánchez-Blázquez, Patricia, E-mail: trujillo@iac.es [Departamento de Física Teórica, Universidad Autónoma de Madrid, E-28049, Cantoblanco, Madrid (Spain)

    2014-01-10

    As early as 10 Gyr ago, galaxies with more than 10{sup 11} M {sub ☉} of stars already existed. While most of these massive galaxies must have subsequently transformed through on-going star formation and mergers with other galaxies, a small fraction (≲0.1%) may have survived untouched until today. Searches for such relic galaxies, useful windows to explore the early universe, have been inconclusive to date: galaxies with masses and sizes like those observed at high redshift (M {sub *} ≳ 10{sup 11} M {sub ☉}; R{sub e} ≲ 1.5 kpc) have been found in the local universe, but their stars are far too young for the galaxy to be a relic galaxy. This paper explores the first case of a nearby galaxy, NGC 1277 (at a distance of 73 Mpc in the Perseus galaxy cluster), which fulfills many criteria to be considered a relic galaxy. Using deep optical spectroscopy, we derive the star formation history along the structure of the galaxy: the stellar populations are uniformly old (>10 Gyr) with no evidence for more recent star formation episodes. The metallicity of their stars is super-solar ([Fe/H] = 0.20 ± 0.04 with a smooth decline toward the outer regions) and α-enriched ([α/Fe] = 0.4 ± 0.1). This suggests a very short formation time scale for the bulk of the stars in this galaxy. This object also rotates very fast (V {sub rot} ∼ 300 km s{sup –1}) and has a large central velocity dispersion (σ > 300 km s{sup –1}). NGC 1277 allows the exploration in full detail of properties such as the structure, internal dynamics, metallicity, and initial mass function as they were at ∼10-12 Gyr ago when the first massive galaxies were built.

  11. Compact Graph Representations and Parallel Connectivity Algorithms for Massive Dynamic Network Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Madduri, Kamesh; Bader, David A.

    2009-02-15

    Graph-theoretic abstractions are extensively used to analyze massive data sets. Temporal data streams from socioeconomic interactions, social networking web sites, communication traffic, and scientific computing can be intuitively modeled as graphs. We present the first study of novel high-performance combinatorial techniques for analyzing large-scale information networks, encapsulating dynamic interaction data in the order of billions of entities. We present new data structures to represent dynamic interaction networks, and discuss algorithms for processing parallel insertions and deletions of edges in small-world networks. With these new approaches, we achieve an average performance rate of 25 million structural updates per second and a parallel speedup of nearly28 on a 64-way Sun UltraSPARC T2 multicore processor, for insertions and deletions to a small-world network of 33.5 million vertices and 268 million edges. We also design parallel implementations of fundamental dynamic graph kernels related to connectivity and centrality queries. Our implementations are freely distributed as part of the open-source SNAP (Small-world Network Analysis and Partitioning) complex network analysis framework.

  12. An Over-Massive Black Hole in the Compact Lenticular Galaxy NGC1277

    CERN Document Server

    Bosch, Remco C E van den; Gültekin, Kayhan; van de Ven, Glenn; van der Wel, Arjen; Walsh, Jonelle L; 10.1038/nature11592

    2012-01-01

    All massive galaxies likely have supermassive black holes at their centers, and the masses of the black holes are known to correlate with properties of the host galaxy bulge component. Several explanations have been proposed for the existence of these locally-established empirical relationships; they include the non-causal, statistical process of galaxy-galaxy merging, direct feedback between the black hole and its host galaxy, or galaxy-galaxy merging and the subsequent violent relaxation and dissipation. The empirical scaling relations are thus important for distinguishing between various theoretical models of galaxy evolution, and they further form the basis for all black hole mass measurements at large distances. In particular, observations have shown that the mass of the black hole is typically 0.1% of the stellar bulge mass of the galaxy. The small galaxy NGC4486B currently has the largest published fraction of its mass in a black hole at 11%. Here we report observations of the stellar kinematics of NGC...

  13. Formation of Massive Galaxies at High Redshift: Cold Streams, Clumpy Disks and Compact Spheroids

    CERN Document Server

    Dekel, Avishai; Ceverino, Daniel

    2009-01-01

    We present a simple theoretical framework for massive galaxies at high redshift, where most of the assembly and star formation occurred. The evolution is governed by the interplay between fueling by smooth and clumpy streams and stabilization by a spheroid, leading to a bimodality in galaxy type by z~3. Disks of giant clumps and high star formation rate (SFR) form when the streams are smoother than average. The streams maintain a dense disk that undergoes gravitational fragmentation into several giant clumps, each a few percent of the disk mass. The disk may reach a disk-to-total mass ratio d~0.5 due to the dark-matter halo before it settles into a steady state with a slowly growing bulge, d=0.5-0.25. The clump interactions self-regulate an unstable disk with a dispersion-to-rotation ratio sigma_r/V=0.3-0.15. Encounters and dynamical friction induce inward clump migration in 10 dynamical times, ~0.5Gyr, while the disk expands in response. The inflowing smooth streams replenish the draining disk and prolong th...

  14. The pressure confined wind of the massive and compact superstar cluster M82-A1

    CERN Document Server

    Silich, Sergiy; Munoz-Tunon, Casiana

    2007-01-01

    The observed parameters of the young superstar cluster M82-A1 and its associated compact HII region are here shown to indicate a low heating efficiency or immediate loss, through radiative cooling, of a large fraction of the energy inserted by stellar winds and supernovae during the early evolution of the cluster. This implies a bimodal hydrodynamic solution which leads to a reduced mass deposition rate into the ISM, with a much reduced outflow velocity. Furthermore, to match the observed parameters of the HII region associated to M82-A1, the resultant star cluster wind is here shown to ought to be confined by a high pressure interstellar medium. The cluster wind parameters, as well as the location of the reverse shock, its cooling length and the radius of the standing outer HII region are derived analytically. All of these properties are then confirmed with a semi-analytical integration of the flow equations, which provides us also with the run of the hydrodynamic variables as a function of radius. The impac...

  15. Two Moderate-Redshift Analogs to Compact Massive Early-Type Galaxies at High Redshifts

    CERN Document Server

    Stockton, Alan; Larson, Kirsten

    2009-01-01

    From a search of a portion of the sky covered by the SDSS and UKIDSS databases, we have located 2 galaxies at z~0.5 that have properties similar to those of the luminous passive compact galaxies found at z~2.5. From Keck moderate-resolution spectroscopy and laser-guided adaptive-optics imaging of these galaxies, we can begin to put together a more detailed picture of what their high-redshift counterparts might be like. Spectral-synthesis models that fit the u to K photometry also seem to give good fits to the spectral features. From these models, we estimate masses in the range of 3-4 10^11 M_sun for both galaxies. Under the assumption that these are spheroidal galaxies, our velocity dispersions give estimated masses about a factor of 3 smaller. However, our high-resolution imaging data indicate that these galaxies are not normal spheroids, and the interpretation of the kinematic data depends critically on the actual morphologies and the nature of the stellar orbits. While recent suggestions that the populati...

  16. Quasi-stellar Object Selection Algorithm Using Time Variability and Machine Learning: Selection of 1620 Quasi-stellar Object Candidates from MACHO Large Magellanic Cloud Database

    Science.gov (United States)

    Kim, Dae-Won; Protopapas, Pavlos; Byun, Yong-Ik; Alcock, Charles; Khardon, Roni; Trichas, Markos

    2011-07-01

    We present a new quasi-stellar object (QSO) selection algorithm using a Support Vector Machine, a supervised classification method, on a set of extracted time series features including period, amplitude, color, and autocorrelation value. We train a model that separates QSOs from variable stars, non-variable stars, and microlensing events using 58 known QSOs, 1629 variable stars, and 4288 non-variables in the MAssive Compact Halo Object (MACHO) database as a training set. To estimate the efficiency and the accuracy of the model, we perform a cross-validation test using the training set. The test shows that the model correctly identifies ~80% of known QSOs with a 25% false-positive rate. The majority of the false positives are Be stars. We applied the trained model to the MACHO Large Magellanic Cloud (LMC) data set, which consists of 40 million light curves, and found 1620 QSO candidates. During the selection none of the 33,242 known MACHO variables were misclassified as QSO candidates. In order to estimate the true false-positive rate, we crossmatched the candidates with astronomical catalogs including the Spitzer Surveying the Agents of a Galaxy's Evolution LMC catalog and a few X-ray catalogs. The results further suggest that the majority of the candidates, more than 70%, are QSOs.

  17. Subarcsecond Imaging of the NGC 6334 I(N) Protocluster: Two Dozen Compact Sources and a Massive Disk Candidate

    CERN Document Server

    Hunter, T R; Cyganowski, C J; Young, K H

    2014-01-01

    Using the SMA and VLA, we have imaged the massive protocluster NGC6334I(N) at high angular resolution (0.5"~650AU) from 6cm to 0.87mm, detecting 18 new compact continuum sources. Three of the new sources are coincident with previously-identified water masers. Together with the previously-known sources, these data bring the number of likely protocluster members to 25 for a protostellar density of ~700 pc^-3. Our preliminary measurement of the Q-parameter of the minimum spanning tree is 0.82 -- close to the value for a uniform volume distribution. All of the (nine) sources with detections at multiple frequencies have SEDs consistent with dust emission, and two (SMA1b and SMA4) also have long wavelength emission consistent with a central hypercompact HII region. Thermal spectral line emission, including CH3CN, is detected in six sources: LTE model fitting of CH3CN(J=12-11) yields temperatures of 72-373K, confirming the presence of multiple hot cores. The fitted LSR velocities range from -3.3 to -7.0 km/s, with a...

  18. Morphology Dependence Of Stellar Age in Quenched Galaxies at Redshift ~ 1.2: Massive Compact Galaxies Are Older Than More Extended Ones

    CERN Document Server

    Williams, Christina C; Bezanson, Rachel; Cappelluti, Nico; Cassata, Paolo; Liu, Teng; Lee, Bomee; Tundo, Elena; Vanzella, Eros

    2016-01-01

    We report the detection of morphology-dependent stellar age in massive quenched galaxies at redshift z~1.2. The sense of the dependence is that compact quenched galaxies are 0.5-2 Gyr older than normal-sized ones. The evidence comes from three different age indicators, Dn4000, H$\\delta_{A}$, and fits to spectral synthesis models, applied to the stacked optical spectra of massive, quenched galaxies observed during the CANDELS project. All age indicators consistently show that the dominant stellar populations of compact passive galaxies are older than those of their normally-sized counterparts, with the Dn4000 and model fitting in excellent quantitative agreement. We detect weak [OII] emission in a fraction of passive galaxies, and the strength of the line, when present, is similar between the two samples; however, compact galaxies have a significantly lower frequency of [OII] emission than normal ones. A fraction of both compact and normal galaxies are also individually detected in the 4 Ms Chandra X-ray image...

  19. Are compact massive galaxies at high-z really quiescent? A mid-infrared to submillimeter study of the GOODS NICMOS Survey sample

    CERN Document Server

    Viero, Marco P; Buitrago, Fernando; Marsden, Gaelen; Bauer, Amanda E; Trujillo, Ignacio; Conselice, Christopher J; Pérez-González, Pablo G; Chapin, Edward L; Devlin, Mark J; Halpern, Mark; Mentuch, Erin; Netterfield, Calvin B; Pascale, Enzo; Rex, Marie; Scott, Douglas; Truch, Matthew D P; Wiebe, Donald V

    2010-01-01

    We present measurements of the average flux densities of massive ($M_{*} \\approx 2\\times 10^{11}~\\rm M_{\\odot}$) galaxies at redshifts $1.7 2$ (spheroid-like) population is forming stars with median [interquartile] $\\rm SFR=57~[36, 83]~\\rm M_{\\odot}~yr^{-1}$. Thus, while the star formation signal in this sample is clearly dominated by disk-like galaxies, on average the compact, spheroid-like population appear to be red but not dead, and that localized, dust obscured star formation is a likely mechanism for size evolution in this population, consistent with several models of galaxy growth.

  20. Lensing of Fast Radio Bursts as a Probe of Compact Dark Matter

    CERN Document Server

    Muñoz, Julian B; Dai, Liang; Kamionkowski, Marc

    2016-01-01

    The possibility that part of the dark matter is made of massive compact halo objects (MACHOs) remains poorly constrained over a wide range of masses, and especially in the $20-100\\, M_\\odot$ window. We show that strong gravitational lensing of extragalactic fast radio bursts (FRBs) by MACHOs of masses larger than $\\sim20\\,M_\\odot$ would result in repeated FRBs with an observable time delay. Strong lensing of an FRB by a lens of mass $M_L$ induces two images, separated by a typical time delay $\\sim$ few $\\times(M_L/30\\, M_\\odot)$ milliseconds. Considering the expected FRB detection rate by upcoming experiments, such as CHIME, of $10^4$ FRBs per year, we should observe from tens to hundreds of repeated bursts yearly, if MACHOs in this window make up all the dark matter. A null search for echoes with just $10^4$ FRBs, would constrain the fraction $f_{\\rm DM}$ of dark matter in MACHOs to $f_{\\rm DM}\\lesssim 0.08$ for $M_L\\gtrsim 20\\,M_\\odot$.

  1. Lensing of Fast Radio Bursts as a Probe of Compact Dark Matter.

    Science.gov (United States)

    Muñoz, Julian B; Kovetz, Ely D; Dai, Liang; Kamionkowski, Marc

    2016-08-26

    The possibility that part of the dark matter is made of massive compact halo objects (MACHOs) remains poorly constrained over a wide range of masses, and especially in the 20-100  M_{⊙} window. We show that strong gravitational lensing of extragalactic fast radio bursts (FRBs) by MACHOs of masses larger than ∼20  M_{⊙} would result in repeated FRBs with an observable time delay. Strong lensing of a FRB by a lens of mass M_{L} induces two images, separated by a typical time delay ∼few×(M_{L}/30  M_{⊙})  msec. Considering the expected FRB detection rate by upcoming experiments, such as canadian hydrogen intensity mapping experiment (CHIME), of 10^{4} FRBs per year, we should observe from tens to hundreds of repeated bursts yearly, if MACHOs in this window make up all the dark matter. A null search for echoes with just 10^{4} FRBs would constrain the fraction f_{DM} of dark matter in MACHOs to f_{DM}≲0.08 for M_{L}≳20  M_{⊙}.

  2. Spectroscopic Confirmation of an Ultra Massive and Compact Galaxy at z=3.35: A Detailed Look at an Early Progenitor of Local Most Massive Ellipticals

    CERN Document Server

    Marsan, Z Cemile; Brammer, Gabriel B; Stefanon, Mauro; Muzzin, Adam; Fernandez-Soto, Alberto; Hainline, Kevin N; Labbe, Ivo; Toft, Sune; van Dokkum, Pieter G

    2014-01-01

    We present the first spectroscopic confirmation of an ultra-massive galaxy at redshift z>3 using data from Keck-NIRSPEC, VLT-Xshooter, and GTC-Osiris. We detect strong [OIII] and Ly$\\alpha$ emission, and weak [OII], CIV, and HeII, placing C1-23152 at a spectroscopic redshift of $z_{spec}$=3.351. The modeling of the emission-line corrected spectral energy distribution results in a best-fit stellar mass of $M_{*}=3.1^{+0.6}_{-0.7}\\times10^{11} M_{\\odot}$, a star-formation rate of 4 in a highly dissipative, intense, and short burst of star formation. C1-23152 is completing its transition to a post-starburst phase while hosting a powerful AGN, potentially responsible for the quenching of the star formation activity.

  3. The MACHO Project Sample of Galactic Bulge High-Amplitude Scuti Stars: Pulsation Behavior and Stellar Properties

    Energy Technology Data Exchange (ETDEWEB)

    Bennett, D.P.; Cook, K.H.; Freeman, K.C.; Geha, M.; Griest, K.; Lehner, M.J.; Marshall, S.L.; McNamara, B.J.; Minniti, D.; Nelson, C.; Peterson, B.A.; Popowski, P.; Pratt, M.R.; Quinn, P.J.; Rodgers, A.W.; Sutherland, W.; Templeton, M.R.; Vandehei, T.; Welch, D.L.

    1999-11-16

    We have detected 90 objects with periods and lightcurve structure similar to those of field {delta} Scuti stars, using the Massive Compact Halo Object (MACHO) Project database of Galactic bulge photometry. If we assume similar extinction values for all candidates and absolute magnitudes similar to those of other field high-amplitude {delta} Scuti stars (HADS), the majority of these objects lie in or near the Galactic bulge. At least two of these objects are likely foreground {delta} Scuti stars, one of which may be an evolved nonradial pulsator, similar to other evolved, disk-population {delta} Scuti stars. We have analyzed the light curves of these objects and find that they are similar to the light curves of field {delta} Scuti stars and the {delta} Scuti stars found by the Optical Gravitational Lens Experiment (OGLE). However, the amplitude distribution of these sources lies between those of low- and high-amplitude {delta} Scuti stars, which suggests that they may be an intermediate population. We have found nine double-mode HADS with frequency ratios ranging from 0.75 to 0.79, four probable double- and multiple-mode objects, and another four objects with marginal detections of secondary modes. The low frequencies (5-14 cycles d{sup -1}) and the observed period ratios of {approx}0.77 suggest that the majority of these objects are evolved stars pulsating in fundamental or first overtone radial modes.

  4. Are the most super-massive dark compact objects harbored at the center of dark matter halos?

    CERN Document Server

    Argüelles, Carlos R

    2014-01-01

    Essay selected for Honorable mention 2014 by the Gravity Research Foundation. We study an isothermal system of semi-degenerate self-gravitating fermions in General Relativity (GR). The most general solutions present mass density profiles with a central degenerate compact core governed by quantum statistics followed by an extended plateau, and ending in a power law behaviour $r^{-2}$. By fixing the fermion mass $m$ in the keV regime, the different solutions depending on the free parameters of the model: the degeneracy and temperature parameters at the center, are systematically constructed along the one-parameter sequences of equilibrium configurations up to the critical point, which is represented by the maximum in a central density ($\\rho_0$) Vs. core mass ($M_c$) diagram. We show that for fully degenerate cores, the Oppenheimer-Volkoff (OV) mass limit $M_{c}^{cr}\\propto M_{pl}^3/m^2$ is obtained, while instead for low degenerate cores, the critical core mass increases showing the temperature effects in a no...

  5. Automatic QSO Selection Using Machine Learning: Application on Massive Astronomical Database

    Science.gov (United States)

    Kim, D.-W.; Protopapas, P.; Alcock, C.; Byun, Y.-I.; Khardon, R.

    2011-07-01

    We present a new QSO (Quasi-Stellar Object) selection algorithm using Support Vector Machine (SVM), a supervised classification method, on a set of multiple extracted times series features such as period, amplitude, color, and autocorrelation value. We train a model that separates QSOs from variable stars, non-variable stars and microlensing events using the richest possible training set consisting of all known types of variables including QSOs from the MAssive Compact Halo Object (MACHO) database. We applied the trained model on the MACHO Large Magellanic Cloud (LMC) dataset, which consists of 40 million lightcurves, and found 1,620 QSO candidates. During the selection none of the 33,242 known MACHO variables were misclassified as QSO candidates. In order to estimate the true false positive rate, we crossmatched the candidates with astronomical catalogs including the Spitzer Surveying the Agents of a Galaxy's Evolution (SAGE) LMC catalog. The results further suggest that the majority of the candidates, more than 70%, are QSOs.

  6. Amistad entre machos adultos de monos aulladores negros y dorados

    Directory of Open Access Journals (Sweden)

    Kowalewski, Martín M.

    2007-01-01

    Full Text Available El éxito reproductivo de los machos depende fundamentalmente del número de hembras que puedan fertilizar. Por lo tanto, los machos deberían competir activamente por las fertilizaciones. Sin embargo, en muchas especies de primates no-humanos, los machos conviven pacíficamente en grupos sociales. En este estudio exploramos las relaciones afiliativas entre machos de Alouatta caraya en la Isla Brasilera (27º 20’ S-58º 40’ W en el Noreste argentino. Dos grupos multimacho fueron estudiados durante 5 días por mes durante el año 2004. Definimos amistad como las interacciones afiliativas en díadas incluyendo proximidad, tolerancia durante la alimentación, interacciones de acicalamiento, y soporte en coaliciones. Por ejemplo, encontramos que los índices de asociación entre individuos basados en distancias y acicalamiento, difieren significativamente de lo esperado por azar a lo largo del año y en diferentes contextos comportamentales (p<0.05. Esto sugiere la existencia de pares de machos que se asociaron con mayor frecuencia que lo esperado por azar en ambos grupos. La existencia de afinidad social entre machos emparentados y no emparentados nos presenta nuevas preguntas en el estudio de la evolución de la amistad en primates no-humanos. Este tipo de estudios permite modelar nuevas ideas acerca de la historia evolutiva de la amistad en humanos.

  7. Measurement of the abundance of stellar mass compact objects in the galactic halo by detecting micro-lenses in the Large Magellanic Cloud; Mesure de l'abondance des astres sombres de masse stellaire dans le halo galactique par la recherche de phenomenes de microlentilles vers les nuages de magellan

    Energy Technology Data Exchange (ETDEWEB)

    Lasserre, Th

    2000-05-09

    Many experimental and theoretical results lead to the conclusion that at least 80 percent of the mass of our Galaxy is dark. Part of this so-called dark matter could be in the form of stellar mass compact objects, called MACHOS; these could be detected using the gravitational microlensing effect. The first generation experiments EROS1 and MACHO have strongly constrained the galactic abundance of objects lighter than 0.01 solar mass to less than 10 percent of the total mass. In parallel, the observation by the MACHO group of massive candidates (half the Sun's mass), numerous enough to constitute 50 percent of galactic dark matter, was a further motivation for the EROS group to extend this search to stellar mass objects in a second phase, EROS2. The present work deals with the analysis of 25 million stellar light curves in the Large Magellanic Cloud, observed for three years in order to extract the rare microlensing candidates and to measure the galactic halo mass fraction in the form of compact objects. After recalling the motivations of this search and the theoretical context, I describe the EROS2 experiment. The observational strategy and the photometric reduction procedures needed to deal with the 1.2 To of data are then presented. A new method to detect micro-lenses is detailed, as well as a discussion of background light curves, poorly known. We do not find enough microlensing candidates to explain the galactic rotation curve; this confirms, and improve on previous EROS1 and EROS2 results. Combining all results from EROS allows to exclude that MACHOS with a mass between 10 e-7 and 10 solar mass are important constituents of the galactic halo. This statement agrees with recent results from the MACHO group, although our interpretations differ, namely on the topics of the location of the lenses, and of a possible contamination of the microlensing ample by background phenomena. (author)

  8. The Next Generation Microlensing Search: SuperMacho

    Energy Technology Data Exchange (ETDEWEB)

    Drake, A; Cook, K; Hiriart, R; Keller, S; Miknaitis, G; Nilolaev, S; Olsen, K; Prochter, G; Rest, A; Schmidt, B; Smith, C; Stubbs, C; Suntzeff, N; Welch, D; Becker, A; Clocchiati, A; Covarrubias, R

    2003-10-27

    Past microlensing experiments such as the MACHO project have discovered the presence of a larger than expected number of microlensing events toward the Large Magellanic Cloud (LMC). These events could represent a large fraction of the dark matter in the halo of our Galaxy, if they are indeed due to halo lenses. However the locations of most of the lenses are poorly defined. The SuperMacho project will detect and follow up {approx}60 microlensing events exhibiting special properties due to binarity, etc., will allow us to better determine the location and nature of the lenses causing the LMC microlensing events.

  9. Weak and compact radio emission in early massive star formation regions: an ionized jet toward G11.11–0.12P1

    Energy Technology Data Exchange (ETDEWEB)

    Rosero, V.; Hofner, P.; McCoy, M. [Physics Department, New Mexico Tech, 801 Leroy Place, Socorro, NM 87801 (United States); Kurtz, S.; Loinard, L.; Carrasco-González, C.; Rodríguez, L. F. [Centro de Radioastronomía y Astrofísica, Universidad Nacional Autónoma de México, Morelia 58090 (Mexico); Menten, K. M.; Wyrowski, F. [Max-Planck-Institute für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn (Germany); Araya, E. D. [Physics Department, Western Illinois University, 1 University Circle, Macomb, IL 61455 (United States); Cesaroni, R. [INAF, Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, I-50125 Firenze (Italy); Ellingsen, S. P., E-mail: viviana@nmt.edu [School of Physical Sciences, University of Tasmania, Private Bag 37, Hobart, Tasmania 7001 (Australia)

    2014-12-01

    We report 1.3 cm and 6 cm continuum observations toward the massive proto-stellar candidate G11.11–0.12P1 using the Karl G. Jansky Very Large Array. We detect a string of four unresolved radio continuum sources coincident with the mid-infrared source in G11P1. The continuum sources have positive spectral indices consistent with a thermal (free-free) ionized jet. The most likely origins of the ionized gas are shocks due to the interaction of a stellar wind with the surrounding high-density material. We also present NIR United Kingdom Infrared Telescope (UKIRT) archival data that show an extended structure detected only at K band (2.2 μm), which is oriented perpendicular to the jet, and that may be scattered light from a circumstellar disk around the massive protostar. Our observations plus the UKIRT archival data thus provide new evidence that a disk/jet system is present in the massive proto-stellar candidate located in the G11.11–0.12P1 core.

  10. On the Reported Death of the MACHO Era

    CERN Document Server

    Quinn, D P; Irwin, M J; Marshall, J; Koch, A; Belokurov, V

    2009-01-01

    We present radial velocity measurements of four wide halo binary candidates from the sample in Chaname & Gould (2004; CG04) which, to date, is the only sample containing a large number of such candidates. The four candidates that we have observed have projected separations >0.1 pc, and include the two widest binaries from the sample, with separations of 0.45 and 1.1 pc. We confirm that three of the four CG04 candidates are genuine, including the one with the largest separation. The fourth candidate, however, is spurious at the 5-sigma level. In the light of these measurements we re-examine the implications for MACHO models of the Galactic halo. Our analysis casts doubt on what MACHO constraints can be drawn from the existing sample of wide halo binaries.

  11. IVOA Compliant Services for the MACHO Data Archive

    CERN Document Server

    Smillie, Jonathan G

    2009-01-01

    The MACHO Project generated two-colour photometric lightcurves for 73 million stars in the LMC, SMC, and the Galactic bulge during its 8 years of observing. This photometry, along with all images from the over 100 thousand observations from which it was derived, and an associated catalogue of 21 thousand LMC variable stars, is now available via web-services which comply with standards defined by the International Virtual Observatory Alliance (IVOA).

  12. Not enough stellar Mass Machos in the Galactic Halo

    CERN Document Server

    Lasserre, T; Albert, J N; Andersen, J; Ansari, R; Aubourg, E; Bareyre, P; Bauer, F; Beaulieu, J P; Blanc, G; Bouquet, A; Char, S; Charlot, X; Couchot, F; Coutures, C; Derue, F; Ferlet, R; Glicenstein, J F; Goldman, B; Gould, A; Graff, D; Gros, M H; Haïssinski, J; Hamilton, J C; Hardin, D; De Kat, J; Kim, A; Lesquoy, E; Loup, C; Magneville, C; Mansoux, B; Marquette, J B; Maurice, E; Milshtein, A I; Moniez, M; Palanque-Delabrouille, Nathalie; Perdereau, O; Prévôt, L; Regnault, N; Rich, J; Spiro, Michel; Vidal-Madjar, A; Vigroux, L; Zylberajch, S

    2000-01-01

    We combine new results from the search for microlensing towards the LargeMagellanic Cloud (LMC) by EROS2 (Experience de Recherche d'Objets Sombres) withlimits previously reported by EROS1 and EROS2 towards both Magellanic Clouds.The derived upper limit on the abundance of stellar mass MACHOs rules out suchobjects as an important component of the Galactic halo if their mass is smallerthan 1 solar mass.

  13. Confirmation of the remarkable compactness of massive quiescent galaxies at z~2.3: early-type galaxies did not form in a simple monolithic collapse

    CERN Document Server

    van Dokkum, Pieter; Kriek, Mariska; Holden, Bradford; Illingworth, Garth; Magee, Daniel; Bouwens, Rychard; Marchesini, Danilo; Quadri, Ryan; Rudnick, Greg; Taylor, Edward; Toft, Sune

    2008-01-01

    Using deep near-infrared spectroscopy Kriek et al. (2006) found that ~45% of massive galaxies at z~2.3 have evolved stellar populations and little or no ongoing star formation. Here we determine the sizes of these quiescent galaxies using deep, high-resolution images obtained with HST/NIC2 and laser guide star-assisted Keck/AO. Considering that their median stellar mass is 1.7x10^11 Solar masses the galaxies are remarkably small, with a median effective radius of 0.9 kpc. Galaxies of similar mass in the nearby Universe have sizes of ~5 kpc and average stellar densities which are two orders of magnitude lower than the z~2.3 galaxies. These results extend earlier work at z~1.5 and confirm previous studies at z>2 which lacked spectroscopic redshifts and imaging of sufficient resolution to resolve the galaxies. Our findings demonstrate that fully assembled early-type galaxies make up at most ~10% of the population of K-selected quiescent galaxies at z~2.3, effectively ruling out simple monolithic models for their...

  14. Gravitational waves from a compact star in a circular, inspiral orbit, in the equatorial plane of a massive, spinning black hole, as observed by LISA

    Energy Technology Data Exchange (ETDEWEB)

    Finn, Lee Samuel; Thorne, Kip S.

    2000-12-15

    Results are presented from high-precision computations of the orbital evolution and emitted gravitational waves for a stellar-mass object spiraling into a massive black hole in a slowly shrinking, circular, equatorial orbit. The focus of these computations is inspiral near the innermost stable circular orbit (isco) -- more particularly, on orbits for which the angular velocity {Omega} is 0.03{approx}<{Omega}/{Omega}{sub isco}{<=}1.0. The computations are based on the Teuksolsky-Sasaki-Nakamura formalism, and the results are tabulated in a set of functions that are of order unity and represent relativistic corrections to low-orbital-velocity formulas. These tables can form a foundation for future design studies for the LISA space-based gravitational-wave mission. A first survey of applications to LISA is presented: Signal to noise ratios S/N are computed and graphed as functions of the time-evolving gravitational-wave frequency for the lowest three harmonics of the orbital period, and for various representative values of the hole's mass M and spin a and the inspiraling object's mass {mu}, with the distance to Earth chosen to be r{sub o}=1 Gpc. These S/N's show a very strong dependence on the black-hole spin, as well as on M and {mu}. Graphs are presented showing the range of the {l_brace}M,a,{mu}{r_brace} parameter space, for which S/N>10 at r{sub 0}=1 Gpc during the last year of inspiral. The hole's spin a has a factor of {approx}10 influence on the range of M (at fixed {mu}) for which S/N>10, and the presence or absence of a white-dwarf--binary background has a factor of {approx}3 influence. A comparison with predicted event rates shows strong promise for detecting these waves, but not beyond about 1 Gpc if the inspiraling object is a white dwarf or neutron star. This argues for a modest lowering of LISA's noise floor. A brief discussion is given of the prospects for extracting information from the observed waves.

  15. Massive Gravity

    National Research Council Canada - National Science Library

    de Rham, Claudia

    2014-01-01

    We review recent progress in massive gravity. We start by showing how different theories of massive gravity emerge from a higher-dimensional theory of general relativity, leading to the Dvali–Gabadadze–Porrati model (DGP...

  16. Massive gravity

    OpenAIRE

    Claudia de Rham

    2016-01-01

    We review recent progress in massive gravity. We start by showing how different theories of massive gravity emerge from a higher-dimensional theory of general relativity, leading to the Dvali-Gabadadze-Porrati model (DGP), cascading gravity, and ghost-free massive gravity. We then explore their theoretical and phenomenological consistency, proving the absence of Boulware-Deser ghosts and reviewing the Vainshtein mechanism and the cosmological solutions in these models. Finally, we present alt...

  17. Massive Gravity

    OpenAIRE

    de Rham, Claudia

    2014-01-01

    We review recent progress in massive gravity. We start by showing how different theories of massive gravity emerge from a higher-dimensional theory of general relativity, leading to the Dvali-Gabadadze-Porrati model (DGP), cascading gravity, and ghost-free massive gravity. We then explore their theoretical and phenomenological consistency, proving the absence of Boulware-Deser ghosts and reviewing the Vainshtein mechanism and the cosmological solutions in these models. Finally, we present alt...

  18. Massive Gravity

    OpenAIRE

    2014-01-01

    We review recent progress in massive gravity. We start by showing how different theories of massive gravity emerge from a higher-dimensional theory of general relativity, leading to the Dvali–Gabadadze–Porrati model (DGP), cascading gravity, and ghost-free massive gravity. We then explore their theoretical and phenomenological consistency, proving the absence of Boulware–Deser ghosts and reviewing the Vainshtein mechanism and the cosmological solutions in these models. Finally, we present alt...

  19. Massive Stars

    Science.gov (United States)

    Livio, Mario; Villaver, Eva

    2009-11-01

    Participants; Preface Mario Livio and Eva Villaver; 1. High-mass star formation by gravitational collapse of massive cores M. R. Krumholz; 2. Observations of massive star formation N. A. Patel; 3. Massive star formation in the Galactic center D. F. Figer; 4. An X-ray tour of massive star-forming regions with Chandra L. K. Townsley; 5. Massive stars: feedback effects in the local universe M. S. Oey and C. J. Clarke; 6. The initial mass function in clusters B. G. Elmegreen; 7. Massive stars and star clusters in the Antennae galaxies B. C. Whitmore; 8. On the binarity of Eta Carinae T. R. Gull; 9. Parameters and winds of hot massive stars R. P. Kudritzki and M. A. Urbaneja; 10. Unraveling the Galaxy to find the first stars J. Tumlinson; 11. Optically observable zero-age main-sequence O stars N. R. Walborn; 12. Metallicity-dependent Wolf-Raynet winds P. A. Crowther; 13. Eruptive mass loss in very massive stars and Population III stars N. Smith; 14. From progenitor to afterlife R. A. Chevalier; 15. Pair-production supernovae: theory and observation E. Scannapieco; 16. Cosmic infrared background and Population III: an overview A. Kashlinsky.

  20. The M31 pixel lensing plan campaign: MACHO lensing and self-lensing signals

    Energy Technology Data Exchange (ETDEWEB)

    Calchi Novati, S.; Scarpetta, G. [Istituto Internazionale per gli Alti Studi Scientifici (IIASS), Via Pellegrino 19, I-84019 Vietri Sul Mare (Italy); Bozza, V. [Dipartimento di Fisica E. R. Caianiello, Università di Salerno, Via Giovanni Paolo II 132, I-84084 Fisciano (Italy); Bruni, I.; Gualandi, R. [INAF, Osservatorio Astronomico di Bologna, Via Ranzani 1, I-40127 Bologna (Italy); Dall' Ora, M. [INAF, Osservatorio Astronomico di Capodimonte, Salita Moiariello 16, I-80131 Napoli (Italy); De Paolis, F.; Ingrosso, G.; Nucita, A.; Strafella, F. [Dipartimento di Matematica e Fisica E. De Giorgi, Università del Salento, CP 193, I-73100 Lecce (Italy); Dominik, M. [SUPA, University of St Andrews, School of Physics and Astronomy, North Haugh, St Andrews, KY16 9SS (United Kingdom); Jetzer, Ph. [Institute for Theoretical Physics, University of Zürich, Winterthurerstrasse 190, 8057 Zürich (Switzerland); Mancini, L. [Max Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg (Germany); Safonova, M.; Subramaniam, A. [Indian Institute of Astrophysics, Bangalore 560 034 (India); Sereno, M. [Dipartimento di Scienza Applicata e Tecnologia, Politecnico di Torino, Corso Duca degli Abruzzi 24, I-10129 Torino (Italy); Gould, A. [Department of Astronomy, Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States); Collaboration: PLAN Collaboration

    2014-03-10

    We present the final analysis of the observational campaign carried out by the PLAN (Pixel Lensing Andromeda) collaboration to detect a dark matter signal in form of MACHOs through the microlensing effect. The campaign consists of about 1 month/year observations carried out over 4 years (2007-2010) at the 1.5 m Cassini telescope in Loiano (Astronomical Observatory of BOLOGNA, OAB) plus 10 days of data taken in 2010 at the 2 m Himalayan Chandra Telescope monitoring the central part of M31 (two fields of about 13' × 12.'6). We establish a fully automated pipeline for the search and the characterization of microlensing flux variations. As a result, we detect three microlensing candidates. We evaluate the expected signal through a full Monte Carlo simulation of the experiment completed by an analysis of the detection efficiency of our pipeline. We consider both 'self lensing' and 'MACHO lensing' lens populations, given by M31 stars and dark matter halo MACHOs, in M31 and the Milky Way, respectively. The total number of events is consistent with the expected self-lensing rate. Specifically, we evaluate an expected signal of about two self-lensing events. As for MACHO lensing, for full 0.5(10{sup –2}) M {sub ☉} MACHO halos, our prediction is for about four (seven) events. The comparatively small number of expected MACHO versus self-lensing events, together with the small number statistics at our disposal, do not enable us to put strong constraints on that population. Rather, the hypothesis, suggested by a previous analysis, on the MACHO nature of OAB-07-N2, one of the microlensing candidates, translates into a sizeable lower limit for the halo mass fraction in form of the would-be MACHO population, f, of about 15% for 0.5 M {sub ☉} MACHOs.

  1. Galactic Bulge Microlensing Events from the MACHO Collaboration

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, C L; Griest, K; Popowski, P; Cook, K H; Drake, A J; Minniti, D; Myer, D G; Alcock, C; Allsman, R A; Alves, D R; Axelrod, T S; Becker, A C; Bennett, D P; Freeman, K C; Geha, M; Lehner, M J; Marshall, S L; Nelson, C A; Peterson, B A; Quinn, P J; Stubbs, C W; Sutherland, W; Vandehei, T; Welch, D L

    2005-06-16

    The authors present a catalog of 450 relatively high signal-to-noise microlensing events observed by the MACHO collaboration between 1993 and 1999. The events are distributed throughout the fields and, as expected, they show clear concentration toward the Galactic center. No optical depth is given for this sample since no blending efficiency calculation has been performed, and they find evidence for substantial blending. In a companion paper they give optical depths for the sub-sample of events on clump giant source stars, where blending is a less significant effect. Several events with sources that may belong to the Sagittarius dwarf galaxy are identified. For these events even relatively low dispersion spectra could suffice to classify these events as either consistent with Sagittarius membership or as non-Sagittarius sources. Several unusual events, such as microlensing of periodic variable source stars, binary lens events, and an event showing extended source effects are identified. They also identify a number of contaminating background events as cataclysmic variable stars.

  2. Compact Orthoalgebras

    CERN Document Server

    Wilce, A

    2004-01-01

    We initiate a study of topological orthoalgebras (TOAs), concentrating on the compact case. Examples of TOAs include topological orthomodular lattices, and also the projection lattice of a Hilbert space. As the latter example illustrates, a lattice-ordered TOA need not be a topological lattice. However, we show that a compact Boolean TOA is a topological Boolean algebra. Using this, we prove that any compact regular TOA is atomistic, and has a compact center. We prove also that any compact TOA with isolated 0 is of finite height. We then focus on stably ordered TOAs: those in which the upper-set generated by an open set is open. These include both topological orthomodular lattices and interval orthoalgebras -- in particular, projection lattices. We show that the topology of a compact stably-ordered TOA with isolated 0 is determined by that of of its space of atoms.

  3. Increased Understanding of Accretion in Massive YSOs

    Science.gov (United States)

    De Wit, Willem-Jan; Caratti, A.; Kraus, S.

    2017-06-01

    That massive stars up to 20Msol form by disk accretion is by now reasonably well established. We will present the latest observational results for the formation of single and multiple massive YSOs. By means of optical interferometry using the newly commissioned instrument Gravity at the VLT-I, we show the discovery of a young, embedded, 170AU-wide binary and is the most massive and most compact accreting young binary to date. We will also present the results of a multi-site multi-epoch follow-up campaign of the first well studied accretion outburst in a massive YSO.

  4. MASSIVE STAR FORMATION IN THE MAGELLANIC CLOUDS

    Directory of Open Access Journals (Sweden)

    M. Rubio

    2009-01-01

    Full Text Available Multiwavelenghts studies of massive star formation regions in the LMC and SMC reveal that a second generation of stars is being formed in dense molecular clouds located in the surroundings of the massive clusters. These dense molecular clouds have survive the action of massive star UV radiation elds and winds and they appear as compact dense H2 knots in regions of weak CO emission. We present results of observations obtained towards massive star forming regions in the low metallicity molecular clouds in the Magellanic Clouds and investigate its implication on star formation in the early universe.

  5. Efecto del color del oponente en el desencadenamiento de la agresividad en los machos de Betta splendens

    OpenAIRE

    Remón Ugarte, Estíbaliz

    2012-01-01

    [ES] Los machos de Betta splendens se muestran más agresivos ante la presencia de otros machos de la misma especie y color similar al suyo, en comparación con la agresividad desplegada ante machos de tonalidad distinta [EN] Betta splendens males show greater aggressive responses when facing against other cospecific males of similar color in comparison with males of different color

  6. An improved quasar detection method in EROS-2 and MACHO LMC datasets

    CERN Document Server

    Pichara, Karim; Kim, Dae-Won; Marquette, Jean-Baptiste; Tisserand, Patrick; 10.1111/j.1365-2966.2012.22061.x

    2013-01-01

    We present a new classification method for quasar identification in the EROS-2 and MACHO datasets based on a boosted version of Random Forest classifier. We use a set of variability features including parameters of a continuous auto regressive model. We prove that continuous auto regressive parameters are very important discriminators in the classification process. We create two training sets (one for EROS-2 and one for MACHO datasets) using known quasars found in the LMC. Our model's accuracy in both EROS-2 and MACHO training sets is about 90% precision and 86% recall, improving the state of the art models accuracy in quasar detection. We apply the model on the complete, including 28 million objects, EROS-2 and MACHO LMC datasets, finding 1160 and 2551 candidates respectively. To further validate our list of candidates, we crossmatched our list with a previous 663 known strong candidates, getting 74% of matches for MACHO and 40% in EROS-2. The main difference on matching level is because EROS-2 is a slightly...

  7. The Evolution and Explosion of Massive Stars

    OpenAIRE

    Sukhbold, Tuguldur

    2016-01-01

    How a massive star ends its life depends upon how that life has been lived - the rotation, mass and composition it was born with, mass loss and exchange, and the complex convective and nuclear burning episodes it experienced along the way. In the end, the presupernova stellar core has a density structure that can be characterized by its "compactness" - essentially how fast the density declines outside the iron core. The likelihood that a massive star explodes, by any means, is sensitive to th...

  8. The MACHO Project HST Follow-Up: The Large Magellanic Cloud Microlensing Source Stars

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, C.A.; /LLNL, Livermore /UC, Berkeley; Drake, A.J.; /Caltech; Cook, K.H.; /LLNL, Livermore /UC, Berkeley; Bennett, D.P.; /Caltech /Notre Dame U.; Popowski, P.; /Garching, Max Planck Inst.; Dalal, N.; /Toronto U.; Nikolaev, S.; /LLNL, Livermore; Alcock, C.; /Caltech /Harvard-Smithsonian Ctr. Astrophys.; Axelrod, T.S.; /Arizona U.; Becker, A.C. /Washington U., Seattle; Freeman, K.C.; /Res. Sch. Astron. Astrophys., Weston Creek; Geha, M.; /Yale U.; Griest, K.; /UC, San Diego; Keller, S.C.; /LLNL, Livermore; Lehner, M.J.; /Harvard-Smithsonian Ctr. Astrophys. /Taipei, Inst. Astron. Astrophys.; Marshall, S.L.; /SLAC; Minniti, D.; /Rio de Janeiro, Pont. U. Catol. /Vatican Astron. Observ.; Pratt, M.R.; /Aradigm, Hayward; Quinn, P.J.; /Western Australia U.; Stubbs, C.W.; /UC, Berkeley /Harvard U.; Sutherland, W.; /Oxford U. /Oran, Sci. Tech. U. /Garching, Max Planck Inst. /McMaster U.

    2009-06-25

    We present Hubble Space Telescope (HST) WFPC2 photometry of 13 microlensed source stars from the 5.7 year Large Magellanic Cloud (LMC) survey conducted by the MACHO Project. The microlensing source stars are identified by deriving accurate centroids in the ground-based MACHO images using difference image analysis (DIA) and then transforming the DIA coordinates to the HST frame. None of these sources is coincident with a background galaxy, which rules out the possibility that the MACHO LMC microlensing sample is contaminated with misidentified supernovae or AGN in galaxies behind the LMC. This supports the conclusion that the MACHO LMC microlensing sample has only a small amount of contamination due to non-microlensing forms of variability. We compare the WFPC2 source star magnitudes with the lensed flux predictions derived from microlensing fits to the light curve data. In most cases the source star brightness is accurately predicted. Finally, we develop a statistic which constrains the location of the Large Magellanic Cloud (LMC) microlensing source stars with respect to the distributions of stars and dust in the LMC and compare this to the predictions of various models of LMC microlensing. This test excludes at {approx}> 90% confidence level models where more than 80% of the source stars lie behind the LMC. Exotic models that attempt to explain the excess LMC microlensing optical depth seen by MACHO with a population of background sources are disfavored or excluded by this test. Models in which most of the lenses reside in a halo or spheroid distribution associated with either the Milky Way or the LMC are consistent which these data, but LMC halo or spheroid models are favored by the combined MACHO and EROS microlensing results.

  9. Efecto del virus de artritis encefalitis caprina en el aparato reproductor de machos caprinos

    OpenAIRE

    Humberto Alejandro Martínez Rodríguez; Hugo Ramírez Álvarez; Jorge Tórtora Pérez; Álvaro Aguilar Setién; Germán Isauro Garrido Fariña; Juan Antonio Montaraz Crespo

    2005-01-01

    Se evaluó el efecto del virus de artritis encefalitis caprina (AEC) en el aparato reproductor de machos caprinos. Catorce machos se dividieron en 4 grupos de estudio: I) testigos no infectados (n=3), II) infectados experimentalmente con la cepa FES-C.UNAM (n=3), III) naturalmente infectados (n=5) y IV) infectados experimentalmente con una cepa de referencia de la colección americana de tipos de cultivo (ATCC) (n=3). Cada 30 días durante todo el experimento (10 meses), se colectó sangre y s...

  10. Comportamiento agresivo del macho del ratón de los volcanes Neotomodon alstoni (Rodentia: Cricetidae)

    OpenAIRE

    Granados, Humberto; Luis, Juana; Agustín CARMONA; Espinosa, Guillermo; Arenas, Teresa

    2015-01-01

    Se estudió el comportamiento agresivo de los machos del ratón de los volcanes, Neotomodon alstoni, con 50 pares de ratones que fueron clasificados como posibles dominantes (O) y subordinados (S) a través del Método de Melzack- Thompson. La agresividad se registró en las combinaciones: O vs. O y S vs. S. Se formaron dos grupos: Grupo 1 con 12 pares de machos O y 13 S, y Grupo Il con JI O y 14 S. En el Grupo I el nivel de agresividad se cuantificó después de una semana de apareamiento y después...

  11. 76 FR 15306 - Macho Springs Power I, LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes...

    Science.gov (United States)

    2011-03-21

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Macho Springs Power I, LLC; Supplemental Notice That Initial Market-Based... above-referenced proceeding of Macho Springs Power I, LLC's application for market-based rate...

  12. The mass function of primordial rogue planet MACHOs in quasar nano-lensing

    NARCIS (Netherlands)

    Schild, R.E; Nieuwenhuizen, T.M.; Gibson, C.H.

    2012-01-01

    The recent Sumi et al (2010 Astrophys. J. 710 1641; 2011 Nature 473 349) detection of free roaming planet mass MACHOs in cosmologically significant numbers recalls their original detection in quasar microlening studies (Colley and Schild 2003 Astrophys. J. 594 97; Schild R E 1996 Astrophys. J. 464

  13. Compact NMR

    Energy Technology Data Exchange (ETDEWEB)

    Bluemich, Bernhard; Haber-Pohlmeier, Sabina; Zia, Wasif [RWTH Aachen Univ. (Germany). Inst. fuer Technische und Makromolekulare Chemie (ITMC)

    2014-06-01

    Nuclear Magnetic Resonance (NMR) spectroscopy is the most popular method for chemists to analyze molecular structures, while Magnetic Resonance Imaging (MRI) is a non-invasive diagnostic tool for medical doctors that provides high-contrast images of biological tissue. In both applications, the sample (or patient) is positioned inside a large, superconducting magnet to magnetize the atomic nuclei. Interrogating radio-frequency pulses result in frequency spectra that provide the chemist with molecular information, the medical doctor with anatomic images, and materials scientist with NMR relaxation parameters. Recent advances in magnet technology have led to a variety of small permanent magnets to allow compact and low-cost instruments. The goal of this book is to provide an introduction to the practical use of compact NMR at a level nearly as basic as the operation of a smart phone.

  14. Compact Vortices

    CERN Document Server

    Bazeia, D; Marques, M A; Menezes, R; Zafalan, I

    2016-01-01

    We study a family of Maxwell-Higgs models, described by the inclusion of a function of the scalar field that represent generalized magnetic permeability. We search for vortex configurations which obey first-order differential equations that solve the equations of motion. We first deal with the asymptotic behavior of the field configurations, and then implement a numerical study of the solutions, the energy density and the magnetic field. We work with the generalized permeability having distinct profiles, giving rise to new models, and we investigate how the vortices behave, compared with the solutions of the corresponding standard models. In particular, we show how to build compact vortices, that is, vortex solutions with the energy density and magnetic field vanishing outside a compact region of the plane.

  15. Compact vortices

    Energy Technology Data Exchange (ETDEWEB)

    Bazeia, D.; Losano, L.; Marques, M.A.; Zafalan, I. [Universidade Federal da Paraiba, Departamento de Fisica, Joao Pessoa, PB (Brazil); Menezes, R. [Universidade Federal da Paraiba, Departamento de Ciencias Exatas, Rio Tinto, PB (Brazil); Universidade Federal de Campina Grande, Departamento de Fisica, Campina Grande, PB (Brazil)

    2017-02-15

    We study a family of Maxwell-Higgs models, described by the inclusion of a function of the scalar field that represent generalized magnetic permeability. We search for vortex configurations which obey first-order differential equations that solve the equations of motion. We first deal with the asymptotic behavior of the field configurations, and then implement a numerical study of the solutions, the energy density and the magnetic field. We work with the generalized permeability having distinct profiles, giving rise to new models, and we investigate how the vortices behave, compared with the solutions of the corresponding standard models. In particular, we show how to build compact vortices, that is, vortex solutions with the energy density and magnetic field vanishing outside a compact region of the plane. (orig.)

  16. ATLASGAL --- towards a complete sample of massive star forming clumps

    CERN Document Server

    Urquhart, J S; Csengeri, T; Wyrowski, F; Schuller, F; Hoare, M G; Lumsden, S L; Mottram, J C; Thompson, M A; Menten, K M; Walmsley, C M; Bronfman, L; Pfalzner, S; König, C; Wienen, M

    2014-01-01

    By matching infrared-selected, massive young stellar objects (MYSOs) and compact HII regions in the RMS survey to massive clumps found in the submillimetre ATLASGAL survey, we have identified ~1000 embedded young massive stars between 280\\degr < $\\ell$ < 350\\degr and 10degr < $\\ell$ < 60\\degr with |b|<1.5degr. Combined with an existing sample of radio-selected methanol masers and compact HII regions, the result is a catalogue of ~1700 massive stars embedded within ~1300 clumps located across the inner Galaxy, containing three observationally distinct subsamples, methanol-maser, MYSO and HII-region associations, covering the most important tracers of massive star formation, thought to represent key stages of evolution. We find that massive star formation is strongly correlated with the regions of highest column density in spherical, centrally condensed clumps. We find no significant differences between the three samples in clump structure or the relative location of the embedded stars, which sug...

  17. The formation of compact groups of galaxies

    Institute of Scientific and Technical Information of China (English)

    马駬; 俞允强

    1999-01-01

    In the compact group of galaxies the galaxies can merge into a few massive ones in a very short time, so they must be formed very recently. On the other hand, according to the theory of structure formation, the denser system should form earlier. By analyzing the apparent paradox, we suggest that the merging process of CDM halo plays an important role in the formation of the compact groups of galaxies: it delays the formation of compact groups of galaxies, and makes the groups of galaxies much denser.

  18. Carcinoma mamario en un canino macho: caracterización clínica e inmunohistoquímica

    OpenAIRE

    JI Arias; Paredes, E.; CG Torres

    2015-01-01

    Las neoplasias mamarias en perros machos son poco comunes, no superando el 2% de la totalidad de casos de tumores mamarios en machos y hembras. Estos han mostrado ser en su mayoría de baja malignidad y positivos a la presencia del receptor de estradiol α. En este reporte se presenta un caso de tumor mamario en un perro mestizo macho, que fue evaluado clínicamente, resuelto quirúrgicamente y estudiado citológica, histológica e inmunohistoquimicamente mediante el estudio de proteínas como recep...

  19. Discovery of Five New R. Coronae Borealis Stars in the MACHO Galactic Bulge Database

    Energy Technology Data Exchange (ETDEWEB)

    Zaniewshi, A; Clayton, G C; Welch, D; Gordon, K D; Minniti, D; Cook, K

    2005-06-16

    We have identified five new R Coronae Borealis (RCB) stars in the Galactic bulge using the MACHO Project photometry database, raising the total number of known Galactic RCB stars to about 40. We have obtained spectra to confirm the identifications. The fact that four out of the five newly identified RCB stars are ''cool'' (T{sub eff} < 6000 K) rather than ''warm'' (T{sub eff} > 6000 K) suggests that the preponderance of warm RCB stars among the existing sample is a selection bias. These cool RCB stars are redder and fainter than their warm counterparts and may have been missed in surveys done with blue plates. Based on the number of new RCB stars discovered in the MACHO bulge fields, there may be {approx}250 RCB stars in the reddened ''exclusion'' zone toward the bulge.

  20. Retrato. Nieto de Unamuno con el busto de su abuelo hecho por Victorio Macho.

    OpenAIRE

    Cuesta (Licenciado)

    2010-01-01

    1 fot.; papel; imagen 9 x 14 cm. - Retrato. Nieto de Unamuno con el busto de su abuelo hecho por Victorio Macho. (Imagen troquelada en papel mate con base de color marfil, medida total 16,9 x 22,7. Sello troquelado del autor en ángulo inferior derecho: "Cuesta, Avda. Blasco Ibanez, 7". ). - Procedencia: fondo Miguel de Unamuno. - Buena Conservación.

  1. Spectroscopy of MACHO 97-SMC-1: Self-Lensing within the Small Magellanic Cloud

    Science.gov (United States)

    Sahu, Kailash C.; Sahu, M. S.

    1998-12-01

    More than a dozen microlensing events have been detected so far toward the LMC, and two have been detected toward the SMC. If all of the lenses are in the Galactic halo, both the LMC and the SMC events are expected to have similar timescales. However, the first event toward the SMC, MACHO 97-SMC-1, had a timescale of 123 days, which is much larger than the typical timescale for the LMC events. Since the observed timescale of the SMC event would need the mass of the halo lens to be ~3 Msolar, it has been argued earlier that the lens must be within the SMC, which we spectroscopically confirm in this Letter. From optical depth estimates, we first show that the stars within the SMC play a dominant role as gravitational lenses and can fully account for the observed microlensing events, mainly due to its large physical depth. We also show that if the lenses are within the Magellanic Clouds, then the SMC events should be longer in duration than the LMC events, a fact that is consistent with the observations. The timescale of the event implies that the mass of the lens is >~2 Msolar if it is in the Milky Way disk or halo, in which case the lens, if it is a normal star, is expected to be bright and should reveal itself in the spectrum. Here, we present an optical spectrum of MACHO 97-SMC-1 obtained in 1997 May that shows that the source is a main-sequence B star. There is no trace of any contribution from the lens, which suggests that the lens is not in the Milky Way disk or halo but is a low-mass star within the SMC. The other alternative, that the lens could be a black hole in the Galactic halo, cannot be ruled out from the spectrum alone, but this is disfavored by the timescales of the LMC events. It is worth noting here that MACHO SMC-98-1 is the only other observed event toward the SMC. This was a binary lens event for which the caustic crossing timescale as observed by the PLANET, MACHO, EROS, and OGLE collaborations suggests that the lens is within the SMC

  2. Globular cluster-massive black hole interactions in galactic centers

    CERN Document Server

    Capuzzo-Dolcetta, R

    2016-01-01

    Many, if not all, galaxies host massive compact objects at their centers. They are present as singularities (super massive black holes) or high density star clusters (nuclear tar clusters). In some cases they coexist, and interact more or less strongly. In this short paper I will talk of the 'merger' globular cluster scenario, which has been shown in the past to be an explanation of the substantial mass accumulation in galactic centers. In particular, I will present the many astrophysical implications of such scenario pointing the attention on the mutual feedback of orbitally decaying globular clusters with massive and super massive black holes.

  3. Antenna Splitting Functions for Massive Particles

    Energy Technology Data Exchange (ETDEWEB)

    Larkoski, Andrew J.; Peskin, Michael E.; /SLAC

    2011-06-22

    An antenna shower is a parton shower in which the basic move is a color-coherent 2 {yields} 3 parton splitting process. In this paper, we give compact forms for the spin-dependent antenna splitting functions involving massive partons of spin 0 and spin 1/2. We hope that this formalism we have presented will be useful in describing the QCD dynamics of the top quark and other heavy particles at LHC.

  4. Testing LMC Microlensing Scenarios: The Discrimination Power of the SuperMACHO Microlensing Survey

    Energy Technology Data Exchange (ETDEWEB)

    Rest, A; Stubbs, C; Becker, A C; Miknaitis, G A; Miceli, A; Covarrubias, R; Hawley, S L; Smith, C; Suntzeff, N B; Olsen, K; Prieto, J; Hiriart, R; Welch, D L; Cook, K; Nikolaev, S; Proctor, G; Clocchiatti, A; Minniti, D; Garg, A; Challis, P; Keller, S C; Scmidt, B P

    2004-05-27

    Characterizing the nature and spatial distribution of the lensing objects that produce the observed microlensing optical depth toward the Large Magellanic Cloud (LMC) remains an open problem. They present an appraisal of the ability of the SuperMACHO Project, a next-generation microlensing survey pointed toward the LMC, to discriminate between various proposed lensing populations. they consider two scenarios: lensing by a uniform foreground screen of objects and self-lensing of LMC stars. The optical depth for ''screen-lensing'' is essentially constant across the face of the LMC; whereas, the optical depth for self-lensing shows a strong spatial dependence. they have carried out extensive simulations, based upon actual data obtained during the first year of the project, to assess the SuperMACHO survey's ability to discriminate between these two scenarios. In the simulations they predict the expected number of observed microlensing events for each of their fields by adding artificial stars to the images and estimating the spatial and temporal efficiency of detecting microlensing events using Monte-Carlo methods. They find that the event rate itself shows significant sensitivity to the choice of the LMC luminosity function shape and other parameters, limiting the conclusions which can be drawn from the absolute rate. By instead determining the differential event rate across the LMC, they can decrease the impact of these systematic uncertainties rendering the conclusions more robust. With this approach the SuperMACHO Project should be able to distinguish between the two categories of lens populations and provide important constraints on the nature of the lensing objects.

  5. Curvas de referencia para valorar el crecimiento físico de ratas machos Wistar

    Directory of Open Access Journals (Sweden)

    Marco Cossio-Bolaños

    2013-12-01

    Full Text Available Introducción: Las ratas Wistar son una de las cepas más populares y utilizadas cotidianamente para la investigación en el laboratorio sirviendo como una importante herramienta de investigación, por lo que, exige el control estricto de variables como la edad, el sexo y el peso corporal, y de esta forma poder extrapolar los resultados al modelo humano. Objetivo: Desarrollar curvas de referencia para valorar el crecimiento físico de ratas machos Wistar en función de la edad cronológica y la maduración somática desde una perspectiva no-invasiva. Metodología: Fueron estudiadas 731 ratas machos Wistar de forma transversal. Se evaluó la edad, peso corporal y la superficie corporal. Se utilizó el método LMS para construir curvas de percentil en función del peso y la maduración somática. Resultados: Las curvas de crecimiento físico propuestas sirven para realizar el seguimiento del crecimiento físico y el diagnóstico del estado nutricional de ratas machos de cepa Wistar. Los puntos de corte prepuestos son: P3, P10, P25, P50, P75, P90 y P97. Conclusión: Los resultados sugieren que los científicos de diversas áreas puedan usar tales referencias, con el objetivo de extrapolar las fases del crecimiento somático de la rata de laboratorio al modelo humano y es una alternativa no-invasiva para valorar el crecimiento y el estado nutricional.

  6. Epidemiology of Massive Transfusion

    DEFF Research Database (Denmark)

    Halmin, Märit; Chiesa, Flaminia; Vasan, Senthil K;

    2016-01-01

    OBJECTIVE: There is an increasing focus on massive transfusion, but there is a paucity of comprehensive descriptions of the massively transfused patients and their outcomes. The objective of this study is to describe the incidence rate of massive transfusion, patient characteristics, and the mort...

  7. Are gluons massive ?

    CERN Document Server

    Gilani, A H S

    2004-01-01

    It is claimed that only one gluon is massless and the other seven gluons are massive. Out of eight gluons, six are colored and two are neutral. Among neutral gluons, one is massless and other one is massive. Massive neutral gluon is heavier than the colored gluons. Gluons can only be predicted by set theory but not by SU(3).

  8. Neutron stars structure in the context of massive gravity

    Science.gov (United States)

    Hendi, S. H.; Bordbar, G. H.; Eslam Panah, B.; Panahiyan, S.

    2017-07-01

    Motivated by the recent interests in spin-2 massive gravitons, we study the structure of neutron star in the context of massive gravity. The modifications of TOV equation in the presence of massive gravity are explored in 4 and higher dimensions. Next, by considering the modern equation of state for the neutron star matter (which is extracted by the lowest order constrained variational (LOCV) method with the AV18 potential), different physical properties of the neutron star (such as Le Chatelier's principle, stability and energy conditions) are investigated. It is shown that consideration of the massive gravity has specific contributions into the structure of neutron star and introduces new prescriptions for the massive astrophysical objects. The mass-radius relation is examined and the effects of massive gravity on the Schwarzschild radius, average density, compactness, gravitational redshift and dynamical stability are studied. Finally, a relation between mass and radius of neutron star versus the Planck mass is extracted.

  9. HADS in the Large Magellanic Cloud: Initial findings from the SuperMACHO project

    Energy Technology Data Exchange (ETDEWEB)

    Garg, A

    2009-07-14

    The SuperMACHO Project is a five-year survey toward the Large Magellanic Cloud (LMC) aimed at understanding the nature of the populations of lenses responsible for the excess microlensing rates observed by the MACHO project. Survey observations were completed in 2006. A rich side-product of this survey is a catalog of variable sources down to a depth of VR 23, including many classes of pulsating variables such as {delta}-Scuti and RR Lyrae. Through their position in the Period-Luminosity diagram and their light curve characteristics we have identified 2323 high amplitude {delta}-Scuti (HADS) having high quality light curves. sing Fourier decomposition of the HADS light curves, we find that the period-luminosity (PL) relation defined by the firt-overtone (FO) pulsators does not show a clear separation from the PL-relation defined by the fundamental (F) pulsators. This differs from other instability strip pulsators such as type c RR Lyrae. We also present evidence for a larger amplitude, subluminous population of HADS similar to that observed in Fornax.

  10. Compaction Behavior of Isomalt after Roll Compaction

    OpenAIRE

    2012-01-01

    The suitability of the new isomalt grade galenIQ™ 801 for dry granulation and following tableting is evaluated in this study. Isomalt alone, as well as a blend of equal parts with dibasic calcium phosphate, is roll compacted and tableted. Particle size distribution and flowability of the granules and friability and disintegration time of the tablets are determined. Tensile strength of tablets is related to the specific compaction force during roll compaction and the tableting force....

  11. Efectos de una dosis baja de bisfenol A sobre el eje reproductor de ratas machos prepúberes

    OpenAIRE

    Gámez, Juan Manuel; Penalba, Romina; Cardoso, Nancy Patricia; Ponzo, Osvaldo Juan; Carbone, Silvia Elena; Pandolfi, Matias; Scacchi, Pablo; Reynoso, Roxana María

    2015-01-01

    El objetivo del presente trabajo fue estudiar el efecto de una dosis baja de bisfenol A (BPA) sobre el eje reproductor de ratas macho prepúberes, expuestas durante la gestación y la lactancia. Se trató a ratas hembra preñadas con una dosis aproximada de exposición de BPA de 3 mg, administrado en el agua de bebida, y el tratamiento continuó durante la lactancia. Las crías macho fueron sacrificadas a los 35 días de vida, etapa prepuberal. Se evaluó el peso corporal durante el desarrollo de las...

  12. AN IMPROVED CATALOG OF HALO WIDE BINARIES AND LIMITS ON HALO DARK MATTER (MACHOS

    Directory of Open Access Journals (Sweden)

    C. Allen

    2014-01-01

    Full Text Available A partir de una extensa b ́squeda en la literatura, hemos construido un cat ́logo mejorado de binarias abiertas u a del halo gal ́ctico. La probable pertenencia de nuestras binarias al halo gal ́ctico fue verificada mediante el a a diagrama de movimiento propio reducido para 252 candidatos. Despu ́s de eliminar las estrellas del disco, e subsisten 212 probables binarias del halo, para 150 de las cuales pudimos calcular ́rbitas gal ́cticas y con ello, o a determinar la fracci ́n de sus vidas que pasan en el disco. Estudiamos la distribuci ́n de separaciones angulares o o (o semiejes esperados para la totalidad del cat ́logo, as ́ como para distintas sub-muestras. Encontramos que, a ı en todos los casos, la distribuci ́n se representa bien por una ley de potencias con exponente −1 (distribuci ́n o o de Oepik hasta distintos l ́ ımites para las separaciones angulares o semiejes esperados. Para las 50 binarias que pasan toda su vida en el disco (entre z = ±500 pc el l ́ ımite es de 19000 au, mientras que para el grupo de binarias que pasa s ́lo el 18% de su vida en el disco el l ́ o ımite que encontramos es de 63000 au. Empleamos este cat ́logo a ımites superiores a las masas de los perturbadores masivos del halo (MACHOs. Tomando en para encontrar l ́ cuenta los efectos din ́micos del disco gal ́ctico, as ́ como la densidad no uniforme del halo, encontramos una a a ı cota superior de 13 M⊙ para la masa de los MACHOs. Esta cota, junto con las cotas inferiores encontradas en otros estudios, pr ́cticamente excluye la existencia de MACHOs en el halo gal ́ctico.

  13. Eclipsing binary stars in the Large and Small Magellanic Clouds from the MACHO project: The Sample

    Energy Technology Data Exchange (ETDEWEB)

    Faccioli, L; Alcock, C; Cook, K; Prochter, G; Protopapas, P; Syphers, D

    2007-03-29

    We present a new sample of 4634 eclipsing binary stars in the Large Magellanic Cloud (LMC), expanding on a previous sample of 611 objects and a new sample of 1509 eclipsing binary stars in the Small Magellanic Cloud (SMC), that were identified in the light curve database of the MACHO project. We perform a cross correlation with the OGLE-II LMC sample, finding 1236 matches. A cross correlation with the OGLE-II SMC sample finds 698 matches. We then compare the LMC subsamples corresponding to center and the periphery of the LMC and find only minor differences between the two populations. These samples are sufficiently large and complete that statistical studies of the binary star populations are possible.

  14. Propuesta de ecuaciones para predecir la composición corporal de ratas machos wistar

    Directory of Open Access Journals (Sweden)

    Marco Antonio Cossio-Bolaños

    2010-04-01

    Full Text Available Introducción: La evaluación de la composición corporal es importante, porque permite conocer el fraccionamiento del peso corporal en peso muscular, peso graso, peso residual y peso óseo, tanto en humanos, como en animales. Objetivos: Validar ecuaciones somáticas para predecir la composición corporal de un modelo tri-compartimental (peso graso, peso libre de grasa y peso residual de ratas machos wistar. Diseño: Estudio de tipo descriptivo de corte transversal. Institución: Facultad de Biología de la universidad estatal UNICAMP, Sao Paulo, Brasil. Material biológico: Ratas machos wistar. Métodos: Se estudió a 10 ratas machos wistar, con un promedio de edad de (X=98,00±10,40 días, se les evaluó el peso corporal (g. Enseguida fueron sacrificados y se procedió al fraccionamiento del peso graso (piel, peso libre de grasa (músculo y hueso y peso residual (PR (g. Los resultados fueron analizados por estadística descriptiva de media aritmética (X, desviación estándar (DE y correlación producto momento de Pearson (r. Para predecir los componentes, se aplicó regresiones estadísticas simples y múltiples, a partir del peso corporal (g y la edad (días como variables independientes. Por otro lado, para verificar la concordancia entre el método directo de disección in vitro con las ecuaciones de regresión, se utilizó el plotaje de Bland y Altman. Principales medidas de resultados: Validación de ecuaciones somáticas para predecir la composición corporal de ratas. Resultados: Se verificó altos coeficientes de correlación (r con el peso corporal y edad, los cuales dieron origen a ecuaciones que permitieron predecir el peso graso (PG = -31,6+(0,361*PT-(0,345*edad (R2=0,73 y peso libre de grasa (PLG = 19,9+(0,453*PT + (0,114*edad (R2=0,94. Sin embargo, el peso residual (PR fue obtenido por medio de una deducción matemática (PR=peso total-(PLG+PG. Así mismo, el plotaje de Bland y Altman permitió determinar alta concordancia

  15. Halo-lensing or Self-lensing? Locating the MACHO Lenses

    Science.gov (United States)

    Nelson, C. A.; Cook, K. H.; Popowski, P.; Drake, A. J.; Marshall, S. L.; Griest, K.; Vandehei, T.; Alcock, C.; Allsman, R. A.; Axelrod, T. S.; Freeman, K. C.; Peterson, B. A.; Alves, D. R.; Becker, A. C.; Stubbs, C. W.; Tomaney, A. B.; Bennett, D. P.; Geha, M.; Lehner, M. J.; Minniti, D.; Pratt, M. R.; Quinn, P. J.; Sutherland, W.; Welch, D.; MACHO Collaboration

    2000-12-01

    There are two principle geometrical arrangements which may explain Large Magellanic Cloud (LMC) microlensing: a) halo-lensing, in which the lensed object is part of the Milky Way galactic halo and b) self-lensing, in which the lensed object is part of the LMC. Self-lensing in turn may be broken into two categories: LMC-LMC self-lensing, in which both the source and the lens reside in the LMC and background self-lensing, in which the lens is a star in the LMC and the source star is drawn from some population behind the LMC. Models suggest the contribution of LMC-LMC self-lensing is small, so the nature of LMC microlensing may be estimated from the location of the microlensing source stars. If the source stars are in the LMC then microlensing is dominated by halo-lensing; conversely if the source stars are located behind the LMC then microlensing is dominated by self-lensing. Since background populations reside behind the LMC, we expect them to be both redder and fainter then the average population of the LMC. We attempt to determine if the MACHO source stars come from such a background population by comparing the HST color-magnitude diagram (CMD) of source stars to the CMD of the average population of the LMC and looking for the effects of extra reddening and extinction. The microlensing source stars are identified by deriving accurate centroids in the ground-based MACHO images using difference image analysis (DIA) and then transforming the DIA coordinates to the HST frame. Preliminary results suggest that halo-lensing accounts for ≳ 40% of the observed microlensing results. Support provided by NASA, DOE, NSF and NPSC.

  16. Machos in M31? Absence of Evidence but not Evidence of Absence

    Energy Technology Data Exchange (ETDEWEB)

    de Jong, Jelte T.A.; Widrow, Lawrence M.; Cseresnjes, Patrick; Kuijken, Konrad; Crotts, Arlin P.S.; Bergier, Alexander; Baltz, Edward A.; Gyuk, Geza; Sackett, Penny D.; Uglesich, Robert R.; Sutherland, Will J.; /Kapteyn Astron. Inst., Groningen /Queen' s U., Kingston /Columbia U., Astron. Astrophys. /Leiden Observ. /KIPAC, Menlo Park /Chicago U.,

    2005-07-14

    We present results of a microlensing survey toward the Andromeda Galaxy (M31) carried out during four observing seasons at the Isaac Newton Telescope (INT). This survey is part of the larger microlensing survey toward M31 performed by the Microlensing Exploration of the Galaxy and Andromeda (MEGA) collaboration. Using a fully automated search algorithm, we indentify 14 candidate microlensing events, three of which are reported here for the first time. Observations obtained at the Mayall telescope are combined with the INT data to produce composite light curves for these candidates. The results from the survey are compared with theoretical predictions for the number and distribution of events. These predictions are based on a Monte Carlo calculation of the detection efficiency and disk-bulge-halo models for M31. The models provide the full phase-space distribution functions (DFs) for the lens and source populations and are motivated by dynamical and observational considerations. They include differential extinction and span a wide range of parameter space characterized primarily by the mass-to-light ratios for the disk and bulge. For most models, the observed event rate is consistent with the rate predicted for self-lensing--a MACHO halo fraction of 30% or higher can be ruled at the 95% confidence level. The event distribution does show a large near-far asymmetry hinting at a halo contribution to the microlensing signal. Two candidate events are located at particularly large projected radii on the far side of the disk. These events are difficult to explain by self lensing and only somewhat easier to explain by MACHO lensing. A possibility is that one of these is due to a lens in a giant stellar stream.

  17. Logistics of massive transfusions.

    Science.gov (United States)

    DeLoughery, Thomas G

    2010-01-01

    Care of the patient with massive bleeding involves more than aggressive surgery and infusion of large amounts of blood products. The proper management of massive transfusions-whether they are in trauma patients or other bleeding patients-requires coordination of the personnel in the surgical suite or the emergency department, the blood bank, and laboratory.

  18. Simplifying Massive Contour Maps

    DEFF Research Database (Denmark)

    Arge, Lars; Deleuran, Lasse Kosetski; Mølhave, Thomas;

    2012-01-01

    We present a simple, efficient and practical algorithm for constructing and subsequently simplifying contour maps from massive high-resolution DEMs, under some practically realistic assumptions on the DEM and contours.......We present a simple, efficient and practical algorithm for constructing and subsequently simplifying contour maps from massive high-resolution DEMs, under some practically realistic assumptions on the DEM and contours....

  19. CANDELS+3D-HST: Compact SFGs at z ~ 2-3, the Progenitors of the First Quiescent Galaxies

    NARCIS (Netherlands)

    Barro, G.; Faber, S. M.; Pérez-González, P. G.; Pacifici, C.; Trump, J. R.; Koo, D. C.; Wuyts, S.; Guo, Y.; Bell, E.; Dekel, A.; Porter, L.; Primack, J.; Ferguson, H.; Ashby, M. L. N.; Caputi, K.; Ceverino, D.; Croton, D.; Fazio, G. G.; Giavalisco, M.; Hsu, L.; Kocevski, D.; Koekemoer, A.; Kurczynski, P.; Kollipara, P.; Lee, J.; McIntosh, D. H.; McGrath, E.; Moody, C.; Somerville, R.; Papovich, C.; Salvato, M.; Santini, P.; Tal, T.; van der Wel, A.; Williams, C. C.; Willner, S. P.; Zolotov, A.

    2014-01-01

    We analyze the star-forming and structural properties of 45 massive (log(M/M ⊙) >10) compact star-forming galaxies (SFGs) at 2 compact quiescent galaxies at z ~ 2. The optical/NIR and far-IR Spitzer/Herschel colors indicate that most compact SFGs are

  20. On Compact Graphs

    Institute of Scientific and Technical Information of China (English)

    Ping WANG; Jiong Sheng LI

    2005-01-01

    Let G be a finite simple graph with adjacency matrix A, and let P(A) be the convex closure of the set of all permutation matrices commuting with A. G is said to be compact if every doubly stochastic matrix which commutes with A is in P(A). In this paper, we characterize 3-regular compact graphs and prove that if G is a connected regular compact graph, G - v is also compact, and give a family of almost regular compact connected graphs.

  1. Compactness in Metric Spaces

    Directory of Open Access Journals (Sweden)

    Nakasho Kazuhisa

    2016-09-01

    Full Text Available In this article, we mainly formalize in Mizar [2] the equivalence among a few compactness definitions of metric spaces, norm spaces, and the real line. In the first section, we formalized general topological properties of metric spaces. We discussed openness and closedness of subsets in metric spaces in terms of convergence of element sequences. In the second section, we firstly formalize the definition of sequentially compact, and then discuss the equivalence of compactness, countable compactness, sequential compactness, and totally boundedness with completeness in metric spaces.

  2. Superdense massive galaxies in the Nearby Universe

    CERN Document Server

    Trujillo, Ignacio; de Lorenzo-Caceres, Adriana; Vazdekis, Alexandre; de la Rosa, Ignacio G; Cava, Antonio

    2009-01-01

    Superdense massive galaxies (r_e~1 kpc; M~10^{11} Msun) were common in the early universe (z>1.5). Within some hierarchical merging scenarios, a non-negligible fraction (1-10%) of these galaxies is expected to survive since that epoch retaining their compactness and presenting old stellar populations in the present universe. Using the NYU Value-Added Galaxy Catalog from the SDSS Data Release 6 we find only a tiny fraction of galaxies (~0.03%) with r_e8x10^{10} Msun in the local Universe (z<0.2). Surprinsingly, they are relatively young (~2 Gyr) and metal-rich ([Z/H]~0.2). The consequences of these findings within the current two competing size evolution scenarios for the most massive galaxies ("dry" mergers vs "puffing up" due to quasar activity) are discussed.

  3. The Dynamics of Massive Starless Cores

    Science.gov (United States)

    Tan, Jonathan; Caselli, P.; Fontani, F.; Kong, S.; Butler, M. J.

    2012-05-01

    Progress towards resolving a decade-long debate about how massive stars form can be made by determining if massive starless cores exist in a state of near virial equilibrium. These are the initial conditions invoked by the Core Accretion model of McKee & Tan (2003). Alternatively, the Competitive Accretion model of Bonnell et al. (2001) requires sub-virial conditions. We have identified 4 prime examples of massive ( 50 Msun) cores from mid-infrared (MIR) extinction mapping (Butler & Tan 2009, 2012) of Infrared Dark Clouds. We have found spectacularly high deuterated fractions of N_2H+ of 0.5 in these objects with the IRAM 30m telescope (Fontani et al. 2011). Thus N_2D+ is expected to be an excellent tracer of the kinematics of these cold, dark cores, where most other molecular tracers are thought to be depleted from the gas phase. We report on ALMA Cycle 0 Compact Configuration Band 6 observations of these 4 cores that probe the N_2D+(3-2) line on scales from 9" down to 2.3", well-matched to the structures we see in MIR extinction and discuss their implications for massive star formation theories.

  4. Supersymmetrizing Massive Gravity

    CERN Document Server

    Malaeb, Ola

    2013-01-01

    When four scalar fields with global Lorentz symmetry are coupled to gravity and take a vacuum expectation value breaking diffeomorphism invariance spontaneously, the graviton becomes massive. This model is supersymmetrized by considering four N=1 chiral superfields with global Lorentz symmetry. When the scalar components of the chiral multiplets z^A acquire a vacuum expectation value, both diffeomorphism invariance and local supersymmetry are broken spontaneously. The global Lorentz index A becomes identified with the space-time Lorentz index making the scalar fields z^A vectors and the chiral spinors \\psi^A spin-3/2 Rarita-Schwinger fields. The global supersymmetry is promoted to a local one using the rules of tensor calculus of coupling the N=1 supergravity Lagrangian to the four chiral multiplets. We show that the spectrum of the model in the broken phase consists of a massive spin-2 field, two massive spin-3/2 fields with different mass and a massive vector.

  5. Peculiarities of massive vectormesons

    CERN Document Server

    Schroer, Bert

    2015-01-01

    Massive QED, different from its massless counterpart, posesses two conserved charges; one is a screened (vanishing) Maxwell charge which is directly associated with the massive vectormesons through the identically conserved Maxwell current while the particle-antiparticle counting charge has its origin on the matter side. A somewhat peculiar situation arises in case of A-H couplings to Hermitian matter fields; in that case the only current is the screened Maxwell current and the coupling disappears in the massless limit. In case of selfinteracting massive vectormesons the situation becomes even more peculiar in that the usually renormalizability guaranteeing validity of the first order power-counting criterion breaks down in second order and requires the compensatory presence of an additional A-H coupling. In this case the massive counterpart of (spinor or scalar) QCD needs the presence of the A-H coupling which only disappears in the massless limit. Some aspect of these observation have already been noticed i...

  6. Cosmic String Loops as the Seeds of Super-Massive Black Holes

    CERN Document Server

    Bramberger, Sebastian F; Jreidini, Paul; Quintin, Jerome

    2015-01-01

    Recent discoveries of super-massive black holes at high redshifts indicate a possible tension with the standard Lambda CDM paradigm of early universe cosmology which has difficulties in explaining the origin of the required nonlinear compact seeds which trigger the formation of these super-massive black holes. Here we show that cosmic string loops which result from a scaling solution of strings formed during a phase transition in the very early universe lead to an additional source of compact seeds. The number density of string-induced seeds dominates at high redshifts and can help trigger the formation of the observed super-massive black holes.

  7. PLÁTANO MACHO (Musa aab, CÁRDENAS, TABASCO, MÉXICO

    Directory of Open Access Journals (Sweden)

    Eder Ramos-Hern\\u00E1ndez

    2011-01-01

    Full Text Available Este experimento se realizó en Cárdenas, Tabasco, México en un suelo con textura franca, pH moderadamente ácido, contenido de materia orgánica y nitrógeno total bajo, cultivado con plátano macho, con el objetivo de determinar el control de arvenses con A. pintoi en una plantación de plátano macho. Se utilizó un arreglo factoria l alojado en un diseño de bloques completos al azar, con sombreado y tip o de cobertura vegetal asocia da al plátano como factores, con tres repe ticiones (octubre 2008-agosto 2009. Tanto el factor sombreado como el factor cobertura tuvie ron dos niveles de porcentaje: 45 (s= ± 11,1 y 50 (s= ± 13,2% de sombra, para suelos con arvenses y, con A. pintoi, respectivamente. Se utilizaron los índices de Shannon-Wie ver (H´ y similitud de Sörensen (S para determinar la riqueza de especie s. A los once meses después de establecido el experimento los valores de H´ no mostrarondiferencias significativas entre los tratamientos, S= 0,8 entre los dos niveles de sombra. Las especie s arvenses dominantes fueron: T. triangulare, S. podophylum, P. paniculatum y C. diffusa. Entre los tratamie ntos probados, el de suelo con arvenses a nivel de 50% de sombra fue el que presentó (p=0,05 mayor producción MS (375,3 ± 83,3 g/m2. La MS producida por A. pintoi fue mayor (p=0,05 con 45% (s= ± 11,1 de sombra (198 g/m2 que la producida a 50% (s= ± 13,2 sombra (150,4 g/m2. Se encontró que el nivel de efectividad de A. pintoi para controlar arvenses fue de 52,3% (con 45 ± 11,1% de sombra y 70,5% (con 50 ± 13,2% sombra.

  8. Quantum massive conformal gravity

    Energy Technology Data Exchange (ETDEWEB)

    Faria, F.F. [Universidade Estadual do Piaui, Centro de Ciencias da Natureza, Teresina, PI (Brazil)

    2016-04-15

    We first find the linear approximation of the second plus fourth order derivative massive conformal gravity action. Then we reduce the linearized action to separated second order derivative terms, which allows us to quantize the theory by using the standard first order canonical quantization method. It is shown that quantum massive conformal gravity is renormalizable but has ghost states. A possible decoupling of these ghost states at high energies is discussed. (orig.)

  9. Real-time acquisition of compact volumetric maps

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Buildingcompact 3D maps of the environment models has become an important research topic. This paper presented an efficient stream decimation algorithm of massive meshes. The algorithm adapted the pre-processing step leading to lower in-core memory consumption. This algorithm is applied to reconstructing compact terrain with mobile robot, achieving satisfying results.

  10. Compaction behavior of isomalt after roll compaction.

    Science.gov (United States)

    Quodbach, Julian; Mosig, Johanna; Kleinebudde, Peter

    2012-09-27

    The suitability of the new isomalt grade galenIQ™ 801 for dry granulation and following tableting is evaluated in this study. Isomalt alone, as well as a blend of equal parts with dibasic calcium phosphate, is roll compacted and tableted. Particle size distribution and flowability of the granules and friability and disintegration time of the tablets are determined. Tensile strength of tablets is related to the specific compaction force during roll compaction and the tableting force. In all cases, the tensile strength increases with raising tableting forces. The specific compaction force has a different influence. For isomalt alone the tensile strength is highest for tablets made from granules prepared at 2 kN/cm and 6 kN/cm and decreases at higher values, i.e., >10 kN/cm. Tensile strength of the blend tablets is almost one third lower compared to the strongest tablets of pure isomalt. Friability of pure isomalt tablets is above the limit. Disintegration time is longest when the tensile strength is at its maximum and decreases with higher porosity and lower tensile strengths. Isomalt proves to be suitable for tableting after roll compaction. Even though the capacity as a binder might not be as high as of other excipients, it is a further alternative for the formulation scientist.

  11. Compaction Behavior of Isomalt after Roll Compaction

    Directory of Open Access Journals (Sweden)

    Peter Kleinebudde

    2012-09-01

    Full Text Available The suitability of the new isomalt grade galenIQ™ 801 for dry granulation and following tableting is evaluated in this study. Isomalt alone, as well as a blend of equal parts with dibasic calcium phosphate, is roll compacted and tableted. Particle size distribution and flowability of the granules and friability and disintegration time of the tablets are determined. Tensile strength of tablets is related to the specific compaction force during roll compaction and the tableting force. In all cases, the tensile strength increases with raising tableting forces. The specific compaction force has a different influence. For isomalt alone the tensile strength is highest for tablets made from granules prepared at 2 kN/cm and 6 kN/cm and decreases at higher values, i.e., >10 kN/cm. Tensile strength of the blend tablets is almost one third lower compared to the strongest tablets of pure isomalt. Friability of pure isomalt tablets is above the limit. Disintegration time is longest when the tensile strength is at its maximum and decreases with higher porosity and lower tensile strengths. Isomalt proves to be suitable for tableting after roll compaction. Even though the capacity as a binder might not be as high as of other excipients, it is a further alternative for the formulation scientist.

  12. Self-Compacting Concrete

    OpenAIRE

    Okamura, Hajime; Ouchi, Masahiro

    2003-01-01

    Self-compacting concrete was first developed in 1988 to achieve durable concrete structures. Since then, various investigations have been carried out and this type of concrete has been used in practical structures in Japan, mainly by large construction companies. Investigations for establishing a rational mix-design method and self-compactability testing methods have been carried out from the viewpoint of making self-compacting concrete a standard concrete.

  13. Self-Compacting Concrete

    OpenAIRE

    Okamura, Hajime; Ouchi, Masahiro

    2003-01-01

    Self-compacting concrete was first developed in 1988 to achieve durable concrete structures. Since then, various investigations have been carried out and this type of concrete has been used in practical structures in Japan, mainly by large construction companies. Investigations for establishing a rational mix-design method and self-compactability testing methods have been carried out from the viewpoint of making self-compacting concrete a standard concrete.

  14. Compact Antenna Range

    Data.gov (United States)

    Federal Laboratory Consortium — Facility consists of a folded compact antenna range including a computer controlled three axis position table, parabolic reflector and RF sources for the measurement...

  15. Compact Polarimetry Potentials

    Science.gov (United States)

    Truong-Loi, My-Linh; Dubois-Fernandez, Pascale; Pottier, Eric

    2011-01-01

    The goal of this study is to show the potential of a compact-pol SAR system for vegetation applications. Compact-pol concept has been suggested to minimize the system design while maximize the information and is declined as the ?/4, ?/2 and hybrid modes. In this paper, the applications such as biomass and vegetation height estimates are first presented, then, the equivalence between compact-pol data simulated from full-pol data and compact-pol data processed from raw data as such is shown. Finally, a calibration procedure using external targets is proposed.

  16. Mechanics of tissue compaction.

    Science.gov (United States)

    Turlier, Hervé; Maître, Jean-Léon

    2015-12-01

    During embryonic development, tissues deform by a succession and combination of morphogenetic processes. Tissue compaction is the morphogenetic process by which a tissue adopts a tighter structure. Recent studies characterized the respective roles of cells' adhesive and contractile properties in tissue compaction. In this review, we formalize the mechanical and molecular principles of tissue compaction and we analyze through the prism of this framework several morphogenetic events: the compaction of the early mouse embryo, the formation of the fly retina, the segmentation of somites and the separation of germ layers during gastrulation.

  17. Compact Polarimetry Potentials

    Science.gov (United States)

    Truong-Loi, My-Linh; Dubois-Fernandez, Pascale; Pottier, Eric

    2011-01-01

    The goal of this study is to show the potential of a compact-pol SAR system for vegetation applications. Compact-pol concept has been suggested to minimize the system design while maximize the information and is declined as the ?/4, ?/2 and hybrid modes. In this paper, the applications such as biomass and vegetation height estimates are first presented, then, the equivalence between compact-pol data simulated from full-pol data and compact-pol data processed from raw data as such is shown. Finally, a calibration procedure using external targets is proposed.

  18. Compact Antenna Range

    Data.gov (United States)

    Federal Laboratory Consortium — Facility consists of a folded compact antenna range including a computer controlled three axis position table, parabolic reflector and RF sources for the measurement...

  19. On Planetary Companions to the MACHO-98-BLG-35 Microlens Star

    CERN Document Server

    Rhie, S H; Becker, A C; Peterson, B A; Fragile, P C; Johnson, B R; Quinn, J L; Crouch, A; Gray, J; King, L; Messenger, B B; Thomson, S; Bond, I A; Abe, F; Carter, B S; Dodd, R J; Hearnshaw, J B; Honda, M; Juga Ku Jun; Kabe, S; Kilmartin, P M; Koribalski, B S; Masuda, K; Matsubara, Y; Muraki, Y; Nakamura, T; Nankivell, G R; Noda, S; Rattenbury, N J; Reid, M; Rumsey, N J; Saitô, T; Sato, H; Sato, S; Sekiguchi, M; Sullivan, D J; Sumi, T; Watase, Y; Yanagisawa, T; Yock, P C M; Yoshizawa, M; Saito, To.

    1999-01-01

    We present observations of microlensing event MACHO-98-BLG-35 which reached a peak magnification factor of almost 80. These observations by the Microlensing Planet Search (MPS) and the MOA Collaborations place strong constraints on the possible planetary system of the lens star and show intriguing evidence of a low mass planet with a mass fraction 4*10^{-5} < \\epsilon < 2*10^{-4}. A giant planet with \\epsilon = 10^{-3} is excluded from 95% of the region between 0.4 and 2.5 R_E from the lens star, where R_E is the Einstein ring radius of the lens. This exclusion region is more extensive than the generic "lensing zone" which is 0.6 - 1.6 R_E. For smaller mass planets, we can exclude 57% of the "lensing zone" for \\epsilon = 10^{-4} and 14% of the lensing zone for \\epsilon = 10^{-5}. The mass fraction \\epsilon = 10^{-5} corresponds to an Earth mass planet for a lensing star of mass ~0.3 M_{sun}. A number of similar events will provide statistically significant constraints on the prevalence of Earth mass pla...

  20. Spectroscopy of MACHO 97-SMC-1 self-lensing within the SMC

    CERN Document Server

    Sahu, K C; Sahu, Kailash C.

    1998-01-01

    More than a dozen microlensing events have been detected so far towards the LMC and 2 towards the SMC. If all the lenses are in the Galactic halo, both the LMC and the SMC events are expected to have similar time scales. However, the first event towards the SMC, MACHO 97-SMC-1, had a time scale of 123 days which is much larger than the typical time scale for the LMC events. From optical depth estimates, we first show that the stars within the SMC play a dominant role as gravitational lenses and can fully account for the observed microlensing events, mainly due to its large physical depth. We also show that if the lenses are within the Magellanic Clouds, then the SMC events should be longer in duration than the LMC events, a fact that is consistent with the observations. The time scale of the event implies that the mass of the lens is >2 solar masses if it is in the Milky Way disk or halo, in which case the lens is expected to be bright and should reveal itself in the spectrum. Here, we present an optical spec...

  1. Som de cabra macho: sonoridade, nordestinidade e masculinidades no forró

    Directory of Open Access Journals (Sweden)

    Felipe Trotta

    2013-01-01

    Full Text Available Neste artigo serão discutidas as complexidades da construção da identidade nordestina articulada a partir de determinadas sonoridades assumidas coletivamente como “características”. Parte-se da ideia de que a noção de nordestinidade está estreitamente relacionada com a ideia de masculinidade. O tipo nordestino, cabra macho e sertanejo forte, é descrito em sons, imagens e narrativas que estabelecem um modelo de masculinidade efetivo, compartilhado em canções e timbres. Como um gênero musical estreitamente identificado com o Nordeste, o forró negocia em seu repertório modos de pensar e acionar essa masculinidade nordestina, ligada às ideias de força e virilidade. Suas sonoridades instrumentais mais características – a sanfona e, atualmente, o naipe de metais – acionam tais modelos e, deste modo, processam e atualizam tanto o pertencimento regional quanto certos modelos de masculinidade.

  2. Theories of the massive star formation: a (short) review

    CERN Document Server

    Hennebelle, Patrick

    2012-01-01

    We briefly review the recent numerical works that have been performed to understand the formation of massive stars. After a brief description of the classical works, we review more specifically $i)$ the problem of building stars more massive than 20 $M_\\odot$ and $ii)$ how to prevent the massive cores to fragment in many objects. Multi-D simulations succeed in circumventing the radiative pressure leading to the formation of massive stars although some questions are still debated regarding how is accretion exactly proceeding. While the core fragmentation is slightly reduced by the radiative feedback and the magnetic field when they are treated separately, it is almost entirely suppressed when both of them are included. This is because, magnetic field by removing angular momentum focusses the flow in a compact region. This makes the radiative feedback very efficient leading to a significant increase of the temperature.

  3. Two Massive, Low-Luminosity Cores Toward Infrared Dark Clouds

    CERN Document Server

    Swift, Jonathan J

    2009-01-01

    This article presents high-resolution interferometric mosaics in the 850 micron waveband of two massive, quiescent infrared dark clouds. The two clouds were chosen based on their likelihood to represent environments preceding the formation of massive stars. The brightest compact sources detected in each cloud have masses of approximately 110 and 60 solar masses with radii < 0.1 pc, implying mean volume densities of approximately 1 million particles per cubic centimeter and mean column densities of about 1 gram per square centimeter. Supplementary data show these cores to be cold and inactive. Low upper limits to their bolometric luminosities and temperatures place them at a very early stage of evolution while current models of massive star formation suggest they have the potential to form massive stars.

  4. Mexican papita viroid and tomato planta macho viroid belong to a single species in the genus Pospiviroid.

    Science.gov (United States)

    Verhoeven, J Th J; Roenhorst, J W; Owens, R A

    2011-08-01

    Tomato planta macho viroid (TPMVd) and Mexican papita viroid (MPVd) are two closely related (>90% sequence identity) members of the genus Pospiviroid. Their current status as members of separate species is based upon the reported ability of TPMVd to replicate in Gomphrena globosa and the inability of this viroid to evoke flower break in N. glutinosa. Characterization of a viroid recently isolated from diseased tomato plants grown in Mexico (identical to GenBank accession GQ131573) casts doubt on this earlier report and indicates that these viroids should be classified as members of a single species. Giving priority to the older name, we propose including both of these viroids in the current species Tomato planta macho viroid.

  5. Machos y brujas en la Patagonia”. Trabajo, masculinidad y espacio de la reproducción

    Directory of Open Access Journals (Sweden)

    Hernán M. Palermo

    2016-05-01

    Full Text Available The title "Machos and Witches in Patagonia" illustrates the core debate of this article and attempts to problematize the processes emphasized by social class and gender relations. "Machos" refers to the social construction of the oil worker as imposed by the production system. Meanwhile, "witches” refers to the witch-hunts of the sixteenth, seventeenth and eighteenth centuries, and the practice in which women were confined to the domestic sphere and their reproductive role of the workforce. Therefore, we want to analyze the link between the production process of the oil workforce inside the production system and outside of their work experiences in Comodoro Rivadavia, Argentinian Patagonia. Given that masculinity and femininity are relational gender positions, we will discuss the role of men and women in the organization of work, as a whole.

  6. Desempenho reprodutivo de ovelhas morada nova submetidas a induÃÃo do estro pelo efeito macho

    OpenAIRE

    2013-01-01

    O presente trabalho teve como objetivo principal avaliar a eficiÃncia do efeito macho como mÃtodo indutivo da atividade estral em trÃs categorias (NulÃparas, PrimÃparas e PlurÃparas) de fÃmeas ovinas mestiÃas (MORADA NOVA X SPRD), e no desempenho reprodutivo, a partir de dados obtidos de manifestaÃÃo de estro; intervalo entre a introduÃÃo do macho e o inÃcio do estro; grau de sincronizaÃÃo; repetiÃÃo de estros; taxa de prenhez; taxa de partos; taxa de gemelaridade e Ãndice de prolificidade. E...

  7. Isolated compact elliptical galaxies: Stellar systems that ran away

    CERN Document Server

    Chilingarian, Igor

    2015-01-01

    Compact elliptical galaxies form a rare class of stellar system (~30 presently known) characterized by high stellar densities and small sizes and often harboring metal-rich stars. They were thought to form through tidal stripping of massive progenitors, until two isolated objects were discovered where massive galaxies performing the stripping could not be identified. By mining astronomical survey data, we have now found 195 compact elliptical galaxies in all types of environment. They all share similar dynamical and stellar population properties. Dynamical analysis for nonisolated galaxies demonstrates the feasibility of their ejection from host clusters and groups by three-body encounters, which is in agreement with numerical simulations. Hence, isolated compact elliptical and isolated quiescent dwarf galaxies are tidally stripped systems that ran away from their hosts.

  8. Compaction properties of isomalt

    NARCIS (Netherlands)

    Bolhuis, Gerad K.; Engelhart, Jeffrey J. P.; Eissens, Anko C.

    2009-01-01

    Although other polyols have been described extensively as filler-binders in direct compaction of tablets, the polyol isomalt is rather unknown as pharmaceutical excipient, in spite of its description in all the main pharmacopoeias. In this paper the compaction properties of different types of ispoma

  9. Compact Information Representations

    Science.gov (United States)

    2016-08-02

    network traffic, information retrieval, and databases are faced with very large, inherently high-dimensional, or naturally streaming datasets. This...proposal aims at developing mathematically rigorous and general- purpose statistical methods based on stable random projections, to achieve compact...detections (e.g., DDoS attacks), machine learning, databases , and search. Fundamentally, compact data representations are highly beneficial because they

  10. Chemically homogeneous evolution in massive binaries

    CERN Document Server

    de Mink, S E; Langer, N; Pols, O R

    2010-01-01

    Rotation can have severe consequences for the evolution of massive stars. It is now considered as one of the main parameters, alongside mass and metallicity that determine the final fate of single stars. In massive, fast rotating stars mixing processes induced by rotation may be so efficient that helium produced in the center is mixed throughout the envelope. Such stars evolve almost chemically homogeneously. At low metallicity they remain blue and compact, while they gradually evolve into Wolf-Rayet stars and possibly into progenitors of long gamma-ray bursts. In binaries this type of evolution may occur because of (I) tides in very close binaries, as a result of (II) spin up by mass transfer, as result of (III) a merger of the two stars and (IV) when one of the components in the binary was born with a very high initial rotation rate. As these stars stay compact, the evolutionary channels are very different from what classical binary evolutionary models predict. In this contribution we discuss examples of ne...

  11. Cosmic decoherence: massive fields

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Junyu [Department of Physics, California Institute of Technology,Pasadena, California 91125 (United States); School of the Gifted Young, University of Science and Technology of China,Hefei, Anhui 230026 (China); Sou, Chon-Man; Wang, Yi [Department of Physics, The Hong Kong University of Science and Technology,Clear Water Bay, Kowloon, Hong Kong (China)

    2016-10-14

    We study the decoherence of massive fields during inflation based on the Zurek’s density matrix approach. With the cubic interaction between inflaton and massive fields, the reduced density matrix for the massive fields can be calculated in the Schrödinger picture which is related to the variance of the non-Gaussian exponent in the wave functional. The decoherence rate is computed in the one-loop form from functional integration. For heavy fields with m≳O(H), quantum fluctuations will easily stay in the quantum state and decoherence is unlikely. While for light fields with mass smaller than O(H), quantum fluctuations are easily decohered within 5∼10 e-folds after Hubble crossing. Thus heavy fields can play a key role in studying problems involving inflationary quantum information.

  12. Cosmic Decoherence: Massive Fields

    CERN Document Server

    Liu, Junyu; Wang, Yi

    2016-01-01

    We study the decoherence of massive fields during inflation based on the Zurek's density matrix approach. With the cubic interaction between inflaton and massive fields, the reduced density matrix for the massive fields can be calculated in the Schr\\"odinger picture which is related to the variance of the non-Gaussian exponent in the wave functional. The decoherence rate is computed in the one-loop form from functional integration. For heavy fields with $m\\gtrsim \\mathcal{O}(H)$, quantum fluctuations will easily stay in the quantum state and decoherence is unlikely. While for light fields with mass smaller than $\\mathcal{O}(H)$, quantum fluctuations are easily decohered within $5\\sim10$ e-folds after Hubble crossing. Thus heavy fields can play a key role in studying problems involving inflationary quantum information.

  13. Compaction properties of isomalt.

    Science.gov (United States)

    Bolhuis, Gerad K; Engelhart, Jeffrey J P; Eissens, Anko C

    2009-08-01

    Although other polyols have been described extensively as filler-binders in direct compaction of tablets, the polyol isomalt is rather unknown as pharmaceutical excipient, in spite of its description in all the main pharmacopoeias. In this paper the compaction properties of different types of ispomalt were studied. The types used were the standard product sieved isomalt, milled isomalt and two types of agglomerated isomalt with a different ratio between 6-O-alpha-d-glucopyranosyl-d-sorbitol (GPS) and 1-O-alpha-d-glucopyranosyl-d-mannitol dihydrate (GPM). Powder flow properties, specific surface area and densities of the different types were investigated. Compactibility was investigated by compression of the tablets on a compaction simulator, simulating the compression on high-speed tabletting machines. Lubricant sensitivity was measured by compressing unlubricated tablets and tablets lubricated with 1% magnesium stearate on an instrumented hydraulic press. Sieved isomalt had excellent flow properties but the compactibility was found to be poor whereas the lubricant sensitivity was high. Milling resulted in both a strong increase in compactibility as an effect of the higher surface area for bonding and a decrease in lubricant sensitivity as an effect of the higher surface area to be coated with magnesium stearate. However, the flow properties of milled isomalt were too bad for use as filler-binder in direct compaction. Just as could be expected, agglomeration of milled isomalt by fluid bed agglomeration improved flowability. The good compaction properties and the low lubricant sensitivity were maintained. This effect is caused by an early fragmentation of the agglomerated material during the compaction process, producing clean, lubricant-free particles and a high surface for bonding. The different GPS/GPM ratios of the agglomerated isomalt types studied had no significant effect on the compaction properties.

  14. The prevalence of dwarf galaxy compact groups over cosmic time

    Science.gov (United States)

    Wiens, Christopher

    2017-01-01

    Galaxy interactions are critical to the evolution of the universe, influencing everything from star formation to the structure of the known universe. By studying galaxy interactions through computer simulations, we are instantaneously able to observe processes that normally take billions of years. “Compact groups” are extremely dense assemblies of at least 3 but typically no more than 10 galaxies that are interacting gravitationally. These groups yield much information about galaxy interactions and mergers in dense environments but are difficult to observe at high redshifts. Compact groups of only dwarf galaxies probe a regime of galaxy evolution that has been hypothesized to be common in the early universe. Here we investigate the populations of such dwarf galaxy compact groups in the Millennium II simulation. Millennium II is a massive n-body simulation of cold dark matter particles on a time scale equivalent to the known universe; allowing us to access to high redshift galaxies and the ability to track their descendants. Our preliminary findings indicate that these dwarf galaxy compact groups do exist in the Millennium II simulation. In the simulation, there is a non-inconsequential number of dwarf compact groups with an evolutionary track that mirrors the more massive compact groups with a peak in groups around a redshift of 2.

  15. Jerarquías sociales y aprendizaje: el papel del condicionamiento pavloviano en la competencia intra sexual en machos de Codorniz japonesa Coturnix Japonica

    OpenAIRE

    Montoya Loaiza, Bibiana Carolina

    2010-01-01

    Los dos experimentos que componen este estudio fueron desarrollados con el propósito de evaluar la existencia de un valor adaptativo en el condicionamiento pavloviano en el contexto del establecimiento de relaciones ganador-perdedor asociadas a la competencia por una pareja reproductiva en machos de codorniz japonesa (Coturnix japonica). Fueron tomados dos tipos de medidas, conductuales y moleculares (paternidades). En el experimento 1, se observaron durante 40 días grupos de tres machos acop...

  16. Problems of Massive Gravities

    CERN Document Server

    Deser, S; Ong, Y C; Waldron, A

    2014-01-01

    The method of characteristics is a key tool for studying consistency of equations of motion; it allows issues such as predictability, maximal propagation speed, superluminality, unitarity and acausality to be addressed without requiring explicit solutions. We review this method and its application to massive gravity theories to show the limitations of these models' physical viability: Among their problems are loss of unique evolution, superluminal signals, matter coupling inconsistencies and micro-acausality (propagation of signals around local closed timelike/causal curves). We extend previous no-go results to the entire three-parameter range of massive gravity theories. It is also argued that bimetric models suffer a similar fate.

  17. Exigência de Lisina para Pintos de Corte Machos Mantidos em Ambiente com Alta Temperatura

    Directory of Open Access Journals (Sweden)

    Borges Aurélio Ferreira

    2002-01-01

    Full Text Available Foram utilizados 400 pintos de corte machos da linhagem Avian Farms, com peso médio de 35 ± 0,15 g, no período de 1 a 21 dias de idade, mantidos em ambiente com alta temperatura ( 29,1 ± 0,39ºC, umidade relativa em 59,7 ± 3,16%, temperatura de globo negro em 28,9 ± 0,42ºC e índice de temperatura de globo e umidade (ITGU em 77,4 ± 0,59. O delineamento utilizado foi o inteiramente casualizado, com cinco tratamentos (1,04; 1,10; 1,16; 1,22; e 1,28% de lisina total na ração, oito repetições e 10 aves por repetição. Avaliou-se o efeito de níveis de lisina total sobre desempenho, consumo de lisina total, deposições de proteína e gordura na carcaça e pesos absoluto e relativo da gordura abdominal e do coração, fígado e intestinos. O fornecimento de ração e água foi à vontade. Os níveis de proteína bruta, minerais e vitaminas atenderam às exigências dos animais. Verificou-se efeito quadrático dos níveis de lisina total da ração sobre o ganho de peso, que aumentou, e a conversão alimentar, que melhorou até os níveis de 1,20 e 1,24%, respectivamente. O consumo de ração não variou, enquanto o consumo de lisina total aumentou em razão dos tratamentos. Não se observou efeito dos níveis de lisina da ração sobre os pesos absoluto e relativo do coração e do intestino e o peso relativo do fígado. No entanto, o peso absoluto do fígado aumentou de forma quadrática até o nível de 1,17% de lisina total da ração. Com relação à taxa de deposição de proteína, constatou-se aumento quadrático até o nível de 1,26% de lisina total, enquanto a taxa de deposição de gordura não variou com o nível de lisina da ração. Concluiu-se que frangos de corte machos no período de 1 a 21 dias de idade, submetidos à alta temperatura (29,1ºC, exigem 1,20% de lisina total, correspondente a 1,02% de lisina digestível.

  18. Lomo de macho: Cuerpo, masculinidad y violencia de un grupo de simpatizantes del fútbol

    Directory of Open Access Journals (Sweden)

    José Antonio Garriga Zucal

    2005-12-01

    Full Text Available En este trabajo analizaremos usos y representaciones corporales de los integrantes de una "hinchada" de fútbol, buscando reconstruir el modelo corporal de estos actores. Pelearse en un estadio contra parcialidades rivales, beber o consumir drogas prohibidas y concebir de forma positiva la gordura son prácticas y representaciones que constituyen a los hinchas y que conforman una particular idea de cuerpo. Estos parámetros forman y delinean una corporalidad que tiene vínculos directos con la masculinidad. Ésta se sustenta en usos y representaciones corporales; la prueba final de ser comprendido como un "verdadero hombre", un "macho", según los estándares del grupo, se concreta por intermedio del rol testimonial del cuerpo. Corporalidad y hombría son vehículos que posibilitan identificar a estos actores con determinados espacios sociales, distinguiéndose de aquellos cuyos usos y prácticas los ubican en las antípodas del mapa socialIn this work we will analyze the uses and corporal representations of a gang hooligans, seeking to reconstruct the corporal pattern of these actors. To fight in a stadium against rival gangs, to drink or to consume forbidden drugs and to conceive the obesity in a positive way are practices and representations that configure the hooligans and that form a particular idea of the body. These parameters outline a corporality that has direct links with the masculine identity. This is based on uses and corporal representations; the final test for being identified as a "true man", as a "male", according to the group standards, is by means of the body's testimonial role. Corporality and manliness are means that facilitate the identification of these actors with certain social spaces, being distinguished of those whose uses and practices locate them in the antipodes of the social map.

  19. Evaluación de canales de bovinos machos engordados en sistemas silvopastoriles

    Directory of Open Access Journals (Sweden)

    Jorge Iraola

    2016-01-01

    Full Text Available Se evaluaron 90 canales de tres ciclos productivos de bovinos machos, cebados en un sistema silvo-pastoril con inclusión de Leucaena leucocephala. Se utilizaron 30 animales por cada ciclo productivo: Cebú, Cebú mestizo y Mestizos lecheros Holstein x Cebú , con un peso vivo de sacrificio entre 399 y 420 kg. Se aplicó un modelo lineal mixto a partir de un PROC MIXED del SAS. Se consideraron, como efectos fijos: ciclo productivo, la interacción de la covarianza del peso al sacrificio con el ciclo productivo; y como aleatorios: el efecto del animal anidado dentro de ciclo productivo y el error residual. Se estudiaron los indicadores: peso sacrificio, peso de la canal caliente, peso de la canal fría, carne, hueso y grasa, el rendimiento de todas las partes de la canal. Se realizaron análisis de regresiones lineales relacionadas con el rendimiento cárnico con el programa estadístico INFOSTAT. Se encontraron diferencias (P<0.05 entre ciclos productivos respecto de la canal y las demás partes. El tercer ciclo presentó el mayor porcentaje de hueso en la canal y menor rendimiento cárnico. Todos los ciclos productivos manifestaron un comportamiento lineal favorable en silvopastoreo con leucaena. Se concluye que los ciclos 1 y 2 tuvieron mejor comportamiento en canal con respecto al tercer ciclo con los animales Mestizos lecheros; lo cual está asociado al plano de alimentación y el peso de sacrificio que condicionaron el rendimiento cárnico.

  20. The Properties of Long Period Variables in the LMC from MACHO

    Energy Technology Data Exchange (ETDEWEB)

    Fraser, O J; Hawley, S L; Cook, K H

    2008-05-06

    We present a new analysis of the long period variables in the Large Magellanic Cloud from the MACHO Variable Star Catalog. Three-quarters of our sample of evolved, variable stars have periodic light curves. We characterize the stars in our sample using the multiple periods found in their frequency spectra. Additionally, we use single-epoch 2MASS measurements to construct the average infrared light curves for different groups of these stars. Comparison with evolutionary models shows that stars on the RGB or the Early AGB often show non-periodic variability, but begin to pulsate with periods on the two shortest period-luminosity sequences (1 & 2) when they brighten to K{sub s} {approx} 13. The stars on the Thermally Pulsing AGB are more likely to pulsate with longer periods that lie on the next two P-L sequences (3 & 4), including the sequence associated with the Miras in the LMC. The Petersen diagram and its variants show that multi-periodic stars on each pair of these sequences (3 & 4, and 1 & 2), typically pulsate with periods associated only with that pair. The periods in these multi-periodic stars become longer and stronger as the star evolves. We further constrain the mechanism behind the long secondary periods (LSPs) seen in half of our sample, and find that there is a close match between the luminosity functions of the LSP stars and all of the stars in our sample, and that these star's pulsation amplitudes are relatively wavelength independent. Although this is characteristic of stellar multiplicity, the large number of these variables is problematic for that explanation.

  1. The Evolution of Compact Binary Star Systems

    Directory of Open Access Journals (Sweden)

    Yungelson, Lev R.

    2006-12-01

    Full Text Available We review the formation and evolution of compact binary stars consisting of white dwarfs (WDs, neutron stars (NSs, and black holes (BHs. Binary NSs and BHs are thought to be the primary astrophysical sources of gravitational waves (GWs within the frequency band of ground-based detectors, while compact binaries of WDs are important sources of GWs at lower frequencies to be covered by space interferometers (LISA. Major uncertainties in the current understanding of properties of NSs and BHs most relevant to the GW studies are discussed, including the treatment of the natal kicks which compact stellar remnants acquire during the core collapse of massive stars and the common envelope phase of binary evolution. We discuss the coalescence rates of binary NSs and BHs and prospects for their detections, the formation and evolution of binary WDs and their observational manifestations. Special attention is given to AM CVn-stars -- compact binaries in which the Roche lobe is filled by another WD or a low-mass partially degenerate helium-star, as these stars are thought to be the best LISA verification binary GW sources.

  2. Massive and Open

    Science.gov (United States)

    Fasimpaur, Karen

    2013-01-01

    MOOCs--massive open online courses--are all the rage these days, with hundreds of thousands of participants signing up and investors plunking down millions to get a piece of the pie. Why is there so much excitement about this new disruptive form of online learning, and how does this model apply to professional learning for teachers? Traditional…

  3. Multiplicity of massive stars

    CERN Document Server

    Preibisch, T; Zinnecker, H; Preibisch, Thomas; Weigelt, Gerd; Zinnecker, Hans

    2000-01-01

    We discuss the observed multiplicity of massive stars and implications on theories of massive star formation. After a short summary of the literature on massive star multiplicity, we focus on the O- and B-type stars in the Orion Nebula Cluster, which constitute a homogenous sample of very young massive stars. 13 of these stars have recently been the targets of a bispectrum speckle interferometry survey for companions. Considering the visual and also the known spectroscopic companions of these stars, the total number of companions is at least 14. Extrapolation with correction for the unresolved systems suggests that there are at least 1.5 and perhaps as much as 4 companions per primary star on average. This number is clearly higher than the mean number of about 0.5 companions per primary star found for the low-mass stars in the general field population and also in the Orion Nebula cluster. This suggests that a different mechanism is at work in the formation of high-mass multiple systems in the dense Orion Nebu...

  4. Massive antenatal fetomaternal hemorrhage

    DEFF Research Database (Denmark)

    Dziegiel, Morten Hanefeld; Koldkjaer, Ole; Berkowicz, Adela

    2005-01-01

    Massive fetomaternal hemorrhage (FMH) can lead to life-threatening anemia. Quantification based on flow cytometry with anti-hemoglobin F (HbF) is applicable in all cases but underestimation of large fetal bleeds has been reported. A large FMH from an ABO-compatible fetus allows an estimation...

  5. Small Valdivia compact spaces

    CERN Document Server

    Kubi's, W; Kubi\\'s, Wieslaw; Michalewski, Henryk

    2005-01-01

    We prove a preservation theorem for the class of Valdivia compact spaces, which involves inverse sequences of ``simple'' retractions. Consequently, a compact space of weight $\\loe\\aleph_1$ is Valdivia compact iff it is the limit of an inverse sequence of metric compacta whose bonding maps are retractions. As a corollary, we show that the class of Valdivia compacta of weight at most $\\aleph_1$ is preserved both under retractions and under open 0-dimensional images. Finally, we characterize the class of all Valdivia compacta in the language of category theory, which implies that this class is preserved under all continuous weight preserving functors.

  6. General Relativity&Compact Stars

    Energy Technology Data Exchange (ETDEWEB)

    Glendenning, Norman K.

    2005-08-16

    Compact stars--broadly grouped as neutron stars and white dwarfs--are the ashes of luminous stars. One or the other is the fate that awaits the cores of most stars after a lifetime of tens to thousands of millions of years. Whichever of these objects is formed at the end of the life of a particular luminous star, the compact object will live in many respects unchanged from the state in which it was formed. Neutron stars themselves can take several forms--hyperon, hybrid, or strange quark star. Likewise white dwarfs take different forms though only in the dominant nuclear species. A black hole is probably the fate of the most massive stars, an inaccessible region of spacetime into which the entire star, ashes and all, falls at the end of the luminous phase. Neutron stars are the smallest, densest stars known. Like all stars, neutron stars rotate--some as many as a few hundred times a second. A star rotating at such a rate will experience an enormous centrifugal force that must be balanced by gravity or else it will be ripped apart. The balance of the two forces informs us of the lower limit on the stellar density. Neutron stars are 10{sup 14} times denser than Earth. Some neutron stars are in binary orbit with a companion. Application of orbital mechanics allows an assessment of masses in some cases. The mass of a neutron star is typically 1.5 solar masses. They can therefore infer their radii: about ten kilometers. Into such a small object, the entire mass of our sun and more, is compressed.

  7. Higgsless superconductivity from topological defects in compact BF terms

    CERN Document Server

    Diamantini, M Cristina

    2014-01-01

    We present a new Higgsless model of superconductivity, inspired from anyon superconductivity but P- and T-invariant and generalizable to any dimension. In D space dimensions it involves a (D-1)-form fictitious pseudovector gauge field which originates from the condensation of topological defects in compact low-energy effective BF theories. In the average field approximation, the corresponding uniform emergent charge creates a gap for the (D-2)-dimensional branes via the Magnus force, the dual of the Lorentz force. One particular combination of intrinsic and emergent charge fluctuations that leaves the total charge distribution invariant constitutes an isolated gapless mode leading to superfluidity. The remaining massive modes organise themselves into a D-dimensional charged, massive vector. There is no massive Higgs scalar as there is no local order parameter. When electromagnetism is switched on, a generalised Higgs phenomenon takes place: the photon eats up not only the gapless mode but the massive vector t...

  8. Compact microchannel system

    Science.gov (United States)

    Griffiths, Stewart

    2003-09-30

    The present invention provides compact geometries for the layout of microchannel columns through the use of turns and straight channel segments. These compact geometries permit the use of long separation or reaction columns on a small microchannel substrate or, equivalently, permit columns of a fixed length to occupy a smaller substrate area. The new geometries are based in part on mathematical analyses that provide the minimum turn radius for which column performance in not degraded. In particular, we find that straight channel segments of sufficient length reduce the required minimum turn radius, enabling compact channel layout when turns and straight segments are combined. The compact geometries are obtained by using turns and straight segments in overlapped or nested arrangements to form pleated or coiled columns.

  9. The effects of host galaxy properties on merging compact binaries detectable by LIGO

    Science.gov (United States)

    O'Shaughnessy, R.; Bellovary, J. M.; Brooks, A.; Shen, S.; Governato, F.; Christensen, C. R.

    2017-01-01

    Cosmological simulations of galaxy formation can produce present-day galaxies with a large range of assembly and star formation histories. A detailed study of the metallicity evolution and star formation history of such simulations can assist in predicting Laser Interferometer Gravitational-Wave Observatory (LIGO)-detectable compact object binary mergers. Recent simulations of compact binary evolution suggest that the compact object merger rate depends sensitively on the progenitor's metallicity. Rare low-metallicity star formation during galaxy assembly can produce more detected compact binaries than typical star formation. Using detailed simulations of galaxy and chemical evolution, we determine how sensitively the compact binary populations of galaxies with a similar present-day appearance depend on the details of their assembly. We also demonstrate by concrete example the extent to which dwarf galaxies overabundantly produce compact binary mergers, particularly binary black holes, relative to more massive galaxies. We discuss the implications for transient multimessenger astronomy with compact binary sources.

  10. Desempenho em confinamento de machos bovinos inteiros Canchim, Aberdeen angus e cruzamentos recíprocos

    Directory of Open Access Journals (Sweden)

    Perotto Daniel

    2002-01-01

    Full Text Available Foram analisados o consumo diário de matéria seca (MS por 100kg de peso vivo (CMS, a conversão alimentar (CA e o ganho de peso médio diário (GMD de 118 machos bovinos inteiros Canchim (Cn, Aberdeen Angus (Ab e cruzamentos recíprocos (CnAb (F1, 3/4Cn+1/4Ab, 5/8Cn+3/8Ab e 11/16Cn+5/16Ab e AbCn (F1, 5/8Ab+3/8Cn e 11/16Ab+5/16Cn. Esses animais foram alimentados em baias individuais por 84 a 95 dias com silagem de milho à vontade mais concentrado (17,8% de PB e 79% de NDT fornecido à base de 1% do peso vivo do animal por dia. As características foram analisadas por um modelo que incluiu os efeitos fixos de ano do confinamento, grupo genético, período e ano x período e o efeito aleatório de animal dentro de grupo genético dentro de ano. A relação MS do concentrado:MS da silagem foi incluída como co-variável no modelo. Posteriormente, as características foram analisadas por um modelo de regressão que incluiu coeficientes representando as frações esperadas de Ab nos genótipos dos animais e das mães e as heterozigoses individual e materna. As médias para CMS, CA e GMD foram 2,44kg de MS/100kg de PV/dia, 6,97kg de MS/kg de GMD e 1,435kg/dia, respectivamente. O grupo genético influenciou o CMS (P<0,01 e o GMD (P<0,06. O Ab igualou-se ao AbCn apresentando maior CMS e menor GMD que o Cn e o CnAb. Não houve heterose para qualquer das características indicando que o cruzamento alternado Cn x Ab seria igual à média das raças paternas.

  11. Minimal massive 3D gravity

    NARCIS (Netherlands)

    Bergshoeff, Eric; Hohm, Olaf; Merbis, Wout; Routh, Alasdair J.; Townsend, Paul K.

    2014-01-01

    We present an alternative to topologically massive gravity (TMG) with the same 'minimal' bulk properties; i.e. a single local degree of freedom that is realized as a massive graviton in linearization about an anti-de Sitter (AdS) vacuum. However, in contrast to TMG, the new 'minimal massive gravity'

  12. New improved massive gravity

    Science.gov (United States)

    Dereli, T.; Yetişmişoğlu, C.

    2016-06-01

    We derive the field equations for topologically massive gravity coupled with the most general quadratic curvature terms using the language of exterior differential forms and a first-order constrained variational principle. We find variational field equations both in the presence and absence of torsion. We then show that spaces of constant negative curvature (i.e. the anti de-Sitter space AdS 3) and constant torsion provide exact solutions.

  13. SO(3) massive gravity

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Chunshan

    2013-11-25

    In this Letter, we propose a massive gravity theory with 5 degrees of freedom. The mass term is constructed by 3 Stückelberg scalar fields, which respects SO(3) symmetry in the fields' configuration. By the analysis on the linear cosmological perturbations, we found that such 5 d.o.f. are free from ghost instability, gradient instability, and tachyonic instability.

  14. Dual massive gravity

    Energy Technology Data Exchange (ETDEWEB)

    Morand, Kevin, E-mail: Kevin.Morand@lmpt.univ-tours.fr [Laboratoire de Mathematiques et Physique Theorique, Universite Francois-Rabelais Tours, Federation Denis Poisson - CNRS, Parc de Grandmont, 37200 Tours (France); Solodukhin, Sergey N., E-mail: Sergey.Solodukhin@lmpt.univ-tours.fr [Laboratoire de Mathematiques et Physique Theorique, Universite Francois-Rabelais Tours, Federation Denis Poisson - CNRS, Parc de Grandmont, 37200 Tours (France)

    2012-08-29

    The linearized massive gravity in three dimensions, over any maximally symmetric background, is known to be presented in a self-dual form as a first order equation which encodes not only the massive Klein-Gordon type field equation but also the supplementary transverse-traceless conditions. We generalize this construction to higher dimensions. The appropriate dual description in d dimensions, additionally to a (non-symmetric) tensor field h{sub {mu}{nu}}, involves an extra rank-(d-1) field equivalently represented by the torsion rank-3 tensor. The symmetry condition for h{sub {mu}{nu}} arises on-shell as a consequence of the field equations. The action principle of the dual theory is formulated. The focus has been made on four dimensions. Solving one of the fields in terms of the other and putting back in the action one obtains two other equivalent formulations of the theory in which the action is quadratic in derivatives. In one of these representations the theory is formulated entirely in terms of a rank-2 non-symmetric tensor h{sub {mu}{nu}}. This quadratic theory is not identical to the Fierz-Pauli theory and contains the coupling between the symmetric and antisymmetric parts of h{sub {mu}{nu}}. Nevertheless, the only singularity in the propagator is the same as in the Fierz-Pauli theory so that only the massive spin-2 particle is propagating. In the other representation, the theory is formulated in terms of the torsion rank-3 tensor only. We analyze the conditions which follow from the field equations and show that they restrict to 5 degrees of freedom thus producing an alternative description to the massive spin-2 particle. A generalization to higher dimensions is suggested.

  15. Phases of massive gravity

    Science.gov (United States)

    Dubovsky, Sergei L.

    2004-10-01

    We systematically study the most general Lorentz-violating graviton mass invariant under three-dimensional Eucledian group. We find that at general values of mass parameters the massive graviton has six propagating degrees of freedom, and some of them are ghosts or lead to rapid classical instabilities. However, there is a number of different regions in the mass parameter space where massive gravity is described by a consistent low-energy effective theory with cutoff ~ (mMPl)1/2. This theory is free of rapid instabilities and vDVZ discontinuity. Each of these regions is characterized by certain fine-tuning relations between mass parameters, generalizing the Fierz Pauli condition. In some cases the required fine-tunings are consequences of the existence of the subgroups of the diffeomorphism group that are left unbroken by the graviton mass. We found two new cases, when the resulting theories have a property of UV insensitivity, i.e. remain well behaved after inclusion of arbitrary higher dimension operators without assuming any fine-tunings among the coefficients of these operators, besides those enforced by the symmetries. These theories can be thought of as generalizations of the ghost condensate model with a smaller residual symmetry group. We briefly discuss what kind of cosmology can one expect in massive gravity and argue that the allowed values of the graviton mass may be quite large, affecting growth of primordial perturbations, structure formation and, perhaps, enhancing the backreaction of inhomogeneities on the expansion rate of the Universe.

  16. The Massive Stellar Population of W49: A Spectroscopic Survey

    CERN Document Server

    Wu, Shi-Wei; Bestenlehner, Joachim M; Henning, Thomas; Pasquali, Anna; Brandner, Wolfgang; Stolte, Andrea

    2016-01-01

    Massive stars form on different scales ranging from large, dispersed OB associations to compact, dense starburst clusters. The complex structure of regions of massive star formation, and the involved short timescales provide a challenge for our understanding of their birth and early evolution. As one of the most massive and luminous star-forming region in our Galaxy, W49 is the ideal place to study the formation of the most massive stars. By classifying the massive young stars deeply embedded into the molecular cloud of W49, we aim to investigate and trace the star formation history of this region. We analyse near-infrared $K$-band spectroscopic observations of W49 from LBT/LUCI combined with $JHK$ images obtained with NTT/SOFI and LBT/LUCI. Based on $JHK$-band photometry and K-band spectroscopy the massive stars are placed in a Hertzsprung Russell diagram. By comparison with evolutionary models, their age and hence the star formation history of W49 can be investigated. Fourteen O type stars as well as two yo...

  17. Macondo transmariconizado: una lectura torcida del realismo mágico en "Paso del macho" de Juan Carlos Bautista

    OpenAIRE

    Hernández, César Othón

    2015-01-01

    El presente artículo examina la novela corta mexicana Paso del macho (2011, Juan Carlos Bautista) a partir del realismo mágico. Desde su aparición en la década de los 60 hasta la actualidad, el realismo mágico ha ganado un prestigio que lo ha convertido, tanto en los imaginarios nacionales latinoamericanos como en la industria editorial de los países del norte, en el modelo representativo de la literatura latinoamericana. En este sentido, podría afirmarse que el realismo mágico es un modelo l...

  18. Efectos reproductivos, endocrinologicos e histologicos del antagonista de GnRH acyline en caninos y felinos machos

    OpenAIRE

    García Romero, Guadalupe

    2012-01-01

    Con el objetivo de contribuir al desarrollo del control farmacológico de la reproducción en caninos y felinos machos, el presente Trabajo de Tesis consistió en describir los efectos endocrinos e histológicos reproductivos de un antagonista de tercera generación del factor liberador de gonadotrofinas (GnRH), acyline, en estas especies. En el primer capítulo, con un diseño aleatorizado y con grupo control, se utilizaron un total de 13 perr...

  19. Evidence for (and Against) Progenitor Bias in the Size Growth of Compact Red Galaxies

    CERN Document Server

    Keating, Stephanie K; Schiavon, Ricardo P; Graves, Genevieve; Damjanov, Ivana; Yan, Renbin; Newman, Jeffrey; Simard, Luc

    2014-01-01

    Most massive passive galaxies are compact at high redshifts, but similarly compact massive galaxies are rare in the local universe. The most common interpretation of this phenomenon is that massive galaxies have grown in size by a factor of about five since redshift z=2. An alternative explanation is that recently quenched massive galaxies are larger (a "progenitor bias"). In this paper we explore the importance of progenitor bias by looking for systematic differences in the stellar populations of compact early-type galaxies in the DEEP2 survey as a function of size. Our analysis is based on applying the statistical technique of bootstrap resampling to constrain differences in the median ages of our samples and to begin to characterize the distribution of stellar populations in our co-added spectra. The light-weighted ages of compact early-type galaxies at redshifts 0.5 < z < 1.4 are compared to those of a control sample of larger galaxies at similar redshifts. We find that massive compact early-type ga...

  20. An Active Black Hole in a Compact Dwarf

    Science.gov (United States)

    Kohler, Susanna

    2016-05-01

    A new type of galaxy has just been added to the galaxy zoo: a small, compact, and old elliptical galaxy that shows signs of a monster black hole actively accreting material in its center. What can this unusual discovery tell us about how compact elliptical galaxies form?A New Galactic BeastCompact elliptical galaxies are an extremely rare early-type dwarf galaxy. Consistent with their name, compact ellipticals are small, very compact collections of ancient stars; these galaxies exhibit a high surface brightness and arent actively forming stars.Optical view of the ancient compact elliptical galaxy SDSS J085431.18+173730.5 (center of image) in an SDSS color composite image. [Adapted from Paudel et al. 2016]Most compact ellipticals are found in dense environments, particularly around massive galaxies. This has led astronomers to believe that compact ellipticals might form via the tidal stripping of a once-large galaxy in interactions with another, massive galaxy. In this model, once the original galaxys outer layers are stripped away, the compact inner bulge component would be left behind as a compact elliptical galaxy. Recent discoveries of a few isolated compact ellipticals, however, have strained this model.Now a new galaxy has been found to confuse our classification schemes: the first-ever compact elliptical to also display signs of an active galactic nucleus. Led by Sanjaya Paudel (Korea Astronomy and Space Science Institute), a team of scientists discovered SDSS J085431.18+173730.5 serendipitously in Sloan Digital Sky Survey data. The team used SDSS images and spectroscopy in combination with data from the Canada-France-Hawaii Telescope to learn more about this unique galaxy.Puzzling CharacteristicsSDSS J085431.18+173730.5 presents an interesting conundrum. Ancient compact ellipticals are supposed to be devoid of gas, with no fuel left to trigger nuclear activity. Yet SDSS J085431.18+173730.5 clearly shows the emission lines that indicate active accretion onto

  1. Compactness theorems of fuzzy semantics

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The relationship among diverse fuzzy semantics vs. the corresponding logic consequence operators has been analyzed systematically. The results that compactness and logical compactness of fuzzy semantics are equivalent to compactness and continuity of the logic consequence operator induced by the semantics respectively have been proved under certain conditions. A general compactness theorem of fuzzy semantics have been established which says that every fuzzy semantics defined on a free algebra with members corresponding to continuous functions is compact.

  2. CANDELS+3D-HST : Compact SFGs at z~2-3, the progenitors of the first quiescent galaxies

    NARCIS (Netherlands)

    Barro, G.; Faber, S. M.; Perez-Gonzalez, P. G.; Pacifici, C.; Trump, J. R.; Koo, D. C.; Wuyts, S.; Guo, Y.; Bell, E.; Dekel, A.; Porter, L.; Primack, J.; Ferguson, H.; Ashby, M. L. N.; Caputi, K.; Ceverino, D.; Croton, D.; Fazio, G. G.; Giavalisco, M.; Hsu, L.; Kocevski, D.; Koekemoer, A.; Kurczynski, P.; Kollipara, P.; Lee, J.; McIntosh, D. H.; McGrath, E.; Moody, C.; Somerville, R.; Papovich, C.; Salvato, M.; Santini, P.; Tal, T.; van der Wel, A.; Williams, C.C.; Willner, S. P.; Zolotov, A.

    2014-01-01

    We analyze the star-forming and structural properties of 45 massive (log(M/M-circle dot) > 10) compact star-forming galaxies (SFGs) at 2 compact quiescent galaxies at z similar to 2. The optical/NIR and far-IR Spitzer/Herschel colors indicate that mos

  3. Intelligent compaction theory of high roller compacted concrete dam

    Institute of Scientific and Technical Information of China (English)

    Liu Donghai

    2012-01-01

    The concept and realization process of intelligent compaction for the construction of high roller compacted concrete dam were presented, as well as the theory of monitoring and intelligent feedback control. Based on the real-time analysis of the compaction index, a multiple regression model of the dam compactness was established and a realime estimation method of compaction quality for the entire work area of roller compacted concrete dam was proposed finally. The adaptive adjustment of the roiling process parameters was achieved, with the speed, the exciting force, the roller pass and the compaction thickness meeting the standards during the whole construction process. As a result, the compaction quality and construction efficiency can be improved. The research provides a new way for the construction quality control of roller compacted concrete dam.

  4. The Evolution of Compact Binary Star Systems

    Directory of Open Access Journals (Sweden)

    Konstantin A. Postnov

    2014-05-01

    Full Text Available We review the formation and evolution of compact binary stars consisting of white dwarfs (WDs, neutron stars (NSs, and black holes (BHs. Mergings of compact-star binaries are expected to be the most important sources for forthcoming gravitational-wave (GW astronomy. In the first part of the review, we discuss observational manifestations of close binaries with NS and/or BH components and their merger rate, crucial points in the formation and evolution of compact stars in binary systems, including the treatment of the natal kicks, which NSs and BHs acquire during the core collapse of massive stars and the common envelope phase of binary evolution, which are most relevant to the merging rates of NS-NS, NS-BH and BH-BH binaries. The second part of the review is devoted mainly to the formation and evolution of binary WDs and their observational manifestations, including their role as progenitors of cosmologically-important thermonuclear SN Ia. We also consider AM CVn-stars, which are thought to be the best verification binary GW sources for future low-frequency GW space interferometers.

  5. The compactness of presupernova stellar cores

    Energy Technology Data Exchange (ETDEWEB)

    Sukhbold, Tuguldur; Woosley, S. E., E-mail: sukhbold@ucolick.org [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States)

    2014-03-01

    The success or failure of the neutrino-transport mechanism for producing a supernova in an evolved massive star is known to be sensitive not only to the mass of the iron core that collapses, but also to the density gradient in the silicon and oxygen shells surrounding that core. Here we study the systematics of a presupernova core's 'compactness' as a function of the mass of the star and the physics used in its calculation. Fine-meshed surveys of presupernova evolution are calculated for stars from 15 to 65 M {sub ☉}. The metallicity and the efficiency of semiconvection and overshoot mixing are both varied and bare carbon-oxygen cores are explored as well as full hydrogenic stars. Two different codes, KEPLER and MESA, are used for the study. A complex interplay of carbon and oxygen burning, especially in shells, can cause rapid variations in the compactness for stars of very nearly the same mass. On larger scales, the distribution of compactness with main sequence mass is found to be robustly non-monotonic, implying islands of 'explodabilty,' particularly around 8-20 M {sub ☉} and 25-30 M {sub ☉}. The carbon-oxygen (CO) core mass of a presupernova star is a better, (though still ambiguous) discriminant of its core structure than the main sequence mass.

  6. The Evolution of Compact Binary Star Systems.

    Science.gov (United States)

    Postnov, Konstantin A; Yungelson, Lev R

    2014-01-01

    We review the formation and evolution of compact binary stars consisting of white dwarfs (WDs), neutron stars (NSs), and black holes (BHs). Mergings of compact-star binaries are expected to be the most important sources for forthcoming gravitational-wave (GW) astronomy. In the first part of the review, we discuss observational manifestations of close binaries with NS and/or BH components and their merger rate, crucial points in the formation and evolution of compact stars in binary systems, including the treatment of the natal kicks, which NSs and BHs acquire during the core collapse of massive stars and the common envelope phase of binary evolution, which are most relevant to the merging rates of NS-NS, NS-BH and BH-BH binaries. The second part of the review is devoted mainly to the formation and evolution of binary WDs and their observational manifestations, including their role as progenitors of cosmologically-important thermonuclear SN Ia. We also consider AM CVn-stars, which are thought to be the best verification binary GW sources for future low-frequency GW space interferometers.

  7. Massively Parallel Genetics.

    Science.gov (United States)

    Shendure, Jay; Fields, Stanley

    2016-06-01

    Human genetics has historically depended on the identification of individuals whose natural genetic variation underlies an observable trait or disease risk. Here we argue that new technologies now augment this historical approach by allowing the use of massively parallel assays in model systems to measure the functional effects of genetic variation in many human genes. These studies will help establish the disease risk of both observed and potential genetic variants and to overcome the problem of "variants of uncertain significance." Copyright © 2016 by the Genetics Society of America.

  8. The sizes of massive quiescent and star forming galaxies at z~4 with ZFOURGE and CANDELS

    CERN Document Server

    Straatman, Caroline M S; Spitler, Lee R; Glazebrook, Karl; Tomczak, Adam; Allen, Rebecca; Brammer, Gabriel B; Cowley, Michael; van Dokkum, Pieter; Kacprzak, Glenn G; Kawinwanichakij, Lalit; Mehrtens, Nicola; Nanayakkara, Themiya; Papovich, Casey; Persson, S Eric; Quadri, Ryan F; Rees, Glen; Tilvi, Vithal; Tran, Kim-Vy; Whitaker, Katherine E

    2015-01-01

    We study the rest-frame ultra-violet sizes of massive (~0.8 x 10^11 M_Sun) galaxies at 3.45 x, between 2compact star-forming galaxies at z~4 and their large rest-frame ultra-violet median sizes suggest that the formation phase of compact cores is very short and/or highly dust obscured.

  9. Massive star forming environments

    Science.gov (United States)

    Devine, Kathryn Elizabeth

    2010-12-01

    We present a study of the earliest stages of massive star formation, in which we focus on Infrared Dark Clouds (IRDCs) and young massive clusters. We present Very Large Array spectral line observations of ammonia (NH 3) and CCS toward four IRDCs. The NH3 lines provide diagnostics of the temperature and density structure within IRDCs. Based upon the NH 3 column density, IRDCs have masses of ˜ 103 to 10 4 M⊙ . We detect twenty NH3 clumps within four IRDCs, with radii regions are presented from the Near Infrared Imager (NIRIM) camera on the 3.5 m WIYN telescope. We report J, H, and K' band photometry in the clusters AFGL437, AFGL5180, and AFGL5142 and use these results to probe the stellar populations, extinction, and ages of the clusters. We find that all three clusters suffer significant extinction (AK ˜1), have ages ≤ 5 Myr, and are actively forming stars. We conclude that the properties of these embedded clusters are consistent with their evolving from IRDC clumps.

  10. Phases of massive gravity

    CERN Document Server

    Dubovsky, S L

    2004-01-01

    We systematically study the most general Lorentz-violating graviton mass invariant under three-dimensional Eucledian group using the explicitly covariant language. We find that at general values of mass parameters the massive graviton has six propagating degrees of freedom, and some of them are ghosts or lead to rapid classical instabilities. However, there is a number of different regions in the mass parameter space where massive gravity can be described by a consistent low-energy effective theory with cutoff $\\sim\\sqrt{mM_{Pl}}$ free of rapid instabilities and vDVZ discontinuity. Each of these regions is characterized by certain fine-tuning relations between mass parameters, generalizing the Fierz--Pauli condition. In some cases the required fine-tunings are consequences of the existence of the subgroups of the diffeomorphism group that are left unbroken by the graviton mass. We found two new cases, when the resulting theories have a property of UV insensitivity, i.e. remain well behaved after inclusion of ...

  11. Limestone compaction: an enigma

    Science.gov (United States)

    Shinn, Eugene A.; Halley, Robert B.; Hudson, J. Harold; Lidz, Barbara H.

    1977-01-01

    Compression of an undisturbed carbonate sediment core under a pressure of 556 kg/cm2 produced a “rock” with sedimentary structures similar to typical ancient fine-grained limestones. Surprisingly, shells, foraminifera, and other fossils were not noticeably crushed, which indicates that absence of crushed fossils in ancient limestones can no longer be considered evidence that limestones do not compact.

  12. Compact rotating cup anemometer

    Science.gov (United States)

    Wellman, J. B.

    1968-01-01

    Compact, collapsible rotating cup anemometer is used in remote locations where portability and durability are factors in the choice of equipment. This lightweight instrument has a low wind-velocity threshold, is capable of withstanding large mechanical shocks while in its stowed configuration, and has fast response to wind fluctuations.

  13. The structural and dynamical properties of compact elliptical galaxies

    Science.gov (United States)

    Yıldırım, Akın; van den Bosch, Remco C. E.; van de Ven, Glenn; Martín-Navarro, Ignacio; Walsh, Jonelle L.; Husemann, Bernd; Gültekin, Kayhan; Gebhardt, Karl

    2017-07-01

    Dedicated photometric and spectroscopic surveys have provided unambiguous evidence for a strong stellar mass-size evolution of galaxies within the last 10 Gyr. The likely progenitors of today's most massive galaxies are remarkably small, discy, passive and have already assembled much of their stellar mass at redshift z = 2. An in-depth analysis of these objects, however, is currently not feasible due to the lack of high-quality, spatially resolved photometric and spectroscopic data. In this paper, we present a sample of nearby compact elliptical galaxies (CEGs), which bear resemblance to the massive and quiescent galaxy population at earlier times. Hubble Space Telescope (HST) and wide-field integral field unit (IFU) data have been obtained, and are used to constrain orbit-based dynamical models and stellar population synthesis (SPS) fits, to unravel their structural and dynamical properties. We first show that our galaxies are outliers in the present-day stellar mass-size relation. They are, however, consistent with the mass-size relation of compact, massive and quiescent galaxies at redshift z = 2. The compact sizes of our nearby galaxies imply high central stellar mass surface densities, which are also in agreement with the massive galaxy population at higher redshift, hinting at strong dissipational processes during their formation. Corroborating evidence for a largely passive evolution within the last 10 Gyr is provided by their orbital distribution as well as their stellar populations, which are difficult to reconcile with a very active (major) merging history. This all supports that we can use nearby CEGs as local analogues of the high-redshift, massive and quiescent galaxy population, thus providing additional constraints for models of galaxy formation and evolution.

  14. Improving the compaction properties of roller compacted calcium carbonate.

    Science.gov (United States)

    Bacher, C; Olsen, P M; Bertelsen, P; Kristensen, J; Sonnergaard, J M

    2007-09-05

    The effects of roller compaction process parameters, morphological forms of calcium carbonate and particle size of sorbitol on flow, compaction and compression properties were investigated. The morphology of the calcium carbonate and the sorbitol particle size were more influential on the compaction properties than the settings of the roller compactor. The roller compaction process was demonstrated to be robust and stable in regard to flowability and compactibility. The flowability of the granules was improved adequately to facilitate compression in a production scale rotary tablet press. By adding sorbitol to the calcium carbonate, the compressibility - characterized by the Walker coefficient W(ID) - and the compactibility C(P) were improved considerably. A correlation between the consolidation characteristics was demonstrated. Compactibility data from the compaction simulator correlated with the tablet press for two of the calcium carbonates, the cubic form and the ground quality.

  15. CANDELS: The progenitors of compact quiescent galaxies at z~2

    CERN Document Server

    Barro, Guillermo; Perez-Gonzalez, Pablo G; Koo, David C; Williams, Christina C; Kocevski, Dale D; Trump, Jonathan R; Mozena, Mark; McGrath, Elizabeth; van der Wel, Arjen; Wuyts, Stijn; Bell, Eric F; Croton, Darren J; Dekel, Avishai; Ashby, M L N; Ferguson, Henry C; Fontana, Adriano; Giavalisco, Mauro; Grogin, Norman A; Guo, Yicheng; Hathi, Nimish P; Hopkins, Philip F; Huang, Kuang-Han; Koekemoer, Anton M; Kartaltepe, Jeyhan S; Lee, Kyoung-Soo; Newman, Jeffrey A; Porter, Lauren A; Primack, Joel R; Ryan, Russell E; Rosario, David; Somerville, Rachel S

    2012-01-01

    We combine high-resolution HST/WFC3 images with multi-wavelength photometry to track the evolution of structure and activity of massive (log(M*) > 10) galaxies at redshifts z = 1.4 - 3 in two fields of the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS). We detect compact, star-forming galaxies (cSFGs) whose number densities, masses, sizes, and star formation rates qualify them as likely progenitors of compact, quiescent, massive galaxies (cQGs) at z = 1.5 - 3. At z > 2 most cSFGs have specific star-formation rates (sSFR = 10^-9 yr^-1) half that of typical, massive SFGs at the same epoch, and host X-ray luminous AGN 30 times (~30%) more frequently. These properties suggest that cSFGs are formed by gas-rich processes (mergers or disk-instabilities) that induce a compact starburst and feed an AGN, which, in turn, quench the star formation on dynamical timescales (few 10^8 yr). The cSFGs are continuously being formed at z = 2 - 3 and fade to cQGs by z = 1.5. After this epoch, cSFGs are r...

  16. The effects of host galaxy properties on merging compact binaries detectable by LIGO

    CERN Document Server

    O'Shaughnessy, Richard; Brooks, Alyson; Shen, Sijing; Governato, Fabio; Christensen, Charlotte

    2016-01-01

    Cosmological simulations of galaxy formation can produce present-day galaxies with a large range of assembly and star formation histories. A detailed study of the metallicity evolution and star formation history of such simulations can assist in predicting LIGO-detectable compact object binary mergers. Recent simulations of compact binary evolution suggest the compact object merger rate depends sensitively on the progenitor's metallicity. Rare low-metallicity star formation during galaxy assembly can produce more detected compact binaries than typical star formation. Using detailed simulations of galaxy and chemical evolution, we determine how sensitively the compact binary populations of galaxies with similar present-day appearance depend on the details of their assembly. We also demonstrate by concrete example the extent to which dwarf galaxies overabundantly produce compact binary mergers, particularly binary black holes, relative to more massive galaxies. We discuss the implications for transient multimes...

  17. NÃveis de isoleucina digestÃvel para suÃnos machos castrados dos 15 aos 30 kg

    OpenAIRE

    Doglas Batista Lazzeri

    2011-01-01

    Com o objetivo de determinar a exigÃncia de isoleucina digestÃvel para suÃnos machos castrados dos 15 aos 30 kg de peso vivo, foram realizados dois experimentos, um de digestibilidade e outro de desempenho. Para determinar o coeficiente de digestibilidade ileal dos aminoÃcidos da raÃÃo basal, foram utilizados 10 suÃnos, machos castrados, mestiÃos, com peso mÃdio inicial de 15,00Â0,27 kg, alojados individualmente em gaiolas de metabolismo, em um delineamento inteiramente ao acaso, com dois tra...

  18. EFECTOS DE LA RELACIÓN HEMBRA: MACHO Y EDAD DE LOS REPRODUCTORES EN EL COMPORTAMIENTO REPRODUCTIVO DE LA CODORNIZ JAPONESA (Coturnix coturnix japónica)

    OpenAIRE

    Valladares Pérez, Jorge; Ingeniero Zootecnista. Práctica Privada (Perú).; Cumpa Gavidia, Marcial Estanislao; Departamento Académico de Producción Animal Facultad de Zootecnia, Universidad Nacional Agraria La Molina (Perú).

    2016-01-01

    El objetivo del presente estudio fue evaluar los efectos de la relación de apareamiento hembra: macho y edad de los reproductores sobre la producción de huevos, fertilidad e incubabilidad de la codorniz japonesa. En este estudio, las codornices reproductoras fueron colocadas en jaulas en relaciones hembra: macho de 3:1, 4:1 y 5:1. Además, las reproductoras fueron separadas en dos grupos de 21 y 47 semanas de edad. Se utilizó el Diseño de Bloques completamente randomizado con arreglo factorial...

  19. Magnetized massive stars as magnetar progenitors

    CERN Document Server

    Hu, Ren-Yu

    2009-01-01

    The origin of ultra-intense magnetic fields on magnetars is a mystery in modern astrophysics. We model the core collapse dynamics of massive progenitor stars with high surface magnetic fields in the theoretical framework of a self-similar general polytropic magnetofluid under the self-gravity with a quasi-spherical symmetry. With the specification of physical parameters such as mass density, temperature, magnetic field and wind mass loss rate on the progenitor stellar surface and the consideration of a rebound shock breaking through the stellar interior and envelope, we find a remnant compact object (i.e. neutron star) left behind at the centre with a radius of $\\sim 10^6$ cm and a mass range of $\\sim 1-3$ solar masses. Moreover, we find that surface magnetic fields of such kind of compact objects can be $\\sim 10^{14}-10^{15}$ G, consistent with those inferred for magnetars which include soft gamma-ray repeaters (SGRs) and anomalous X-ray pulsars (AXPs). The magnetic field enhancement factor critically depend...

  20. Runaway Massive Binaries and Cluster Ejection Scenarios

    CERN Document Server

    McSwain, M V; Boyajian, T S; Grundstrom, E D; Roberts, M S E; Ransom, Scott M.; Boyajian, Tabetha S.; Grundstrom, Erika D.

    2006-01-01

    The production of runaway massive binaries offers key insights into the evolution of close binary stars and open clusters. The stars HD 14633 and HD 15137 are rare examples of such runaway systems, and in this work we investigate the mechanism by which they were ejected from their parent open cluster, NGC 654. We discuss observational characteristics that can be used to distinguish supernova ejected systems from those ejected by dynamical interactions, and we present the results of a new radio pulsar search of these systems as well as estimates of their predicted X-ray flux assuming that each binary contains a compact object. Since neither pulsars nor X-ray emission are observed in these systems, we cannot conclude that these binaries contain compact companions. We also consider whether they may have been ejected by dynamical interactions in the dense environment where they formed, and our simulations of four-body interactions suggest that a dynamical origin is possible but unlikely. We recommend further X-ra...

  1. Massive Storage Systems

    Institute of Scientific and Technical Information of China (English)

    Dan Feng; Hai Jin

    2006-01-01

    To accommodate the explosively increasing amount of data in many areas such as scientific computing and e-Business, physical storage devices and control components have been separated from traditional computing systems to become a scalable, intelligent storage subsystem that, when appropriately designed, should provide transparent storage interface, effective data allocation, flexible and efficient storage management, and other impressive features. The design goals and desirable features of such a storage subsystem include high performance, high scalability, high availability, high reliability and high security. Extensive research has been conducted in this field by researchers all over the world, yet many issues still remain open and challenging. This paper studies five different online massive storage systems and one offline storage system that we have developed with the research grant support from China. The storage pool with multiple network-attached RAIDs avoids expensive store-and-forward data copying between the server and storage system, improving data transfer rate by a factor of 2-3 over a traditional disk array. Two types of high performance distributed storage systems for local-area network storage are introduced in the paper. One of them is the Virtual Interface Storage Architecture (VISA) where VI as a communication protocol replaces the TCP/IP protocol in the system. VISA's performance is shown to achieve better than that of IP SAN by designing and implementing the vSCSI (VI-attached SCSI) protocol to support SCSI commands in the VI network. The other is a fault-tolerant parallel virtual file system that is designed and implemented to provide high I/O performance and high reliability. A global distributed storage system for wide-area network storage is discussed in detail in the paper, where a Storage Service Provider is added to provide storage service and plays the role of user agent for the storage system. Object based Storage Systems not only

  2. Higher dimensional nonlinear massive gravity

    CERN Document Server

    Do, Tuan Q

    2016-01-01

    Inspired by a recent ghost-free nonlinear massive gravity in four-dimensional spacetime, we study its higher dimensional scenarios. As a result, we are able to show the constant-like behavior of massive graviton terms for some well-known metrics such as the Friedmann-Lemaitre-Robertson-Walker, Bianchi type I, and Schwarzschild-Tangherlini-(A)dS metrics in a specific five-dimensional nonlinear massive gravity under an assumption that its fiducial metrics are compatible with physical ones. In addition, some simple cosmological solutions of the five-dimensional massive gravity will be figured out consistently.

  3. ATLASGAL --- properties of compact HII regions and their natal clumps

    CERN Document Server

    Urquhart, J S; Moore, T J T; Purcell, C R; Hoare, M G; Schuller, F; Wyrowski, F; Csengeri, T; Menten, K M; Lumsden, S L; Kurtz, S; Walmsley, C M; Bronfman, L; Morgan, L K; Eden, D J; Russeil, D

    2013-01-01

    We present a complete sample of molecular clumps containing compact and ultra-compact (UC) HII regions between \\ell=10\\degr and 60\\degr\\ and $|b|<1\\degr, identified by combining the the ATLASGAL submm and CORNISH radio continuum surveys with visual examination of archival infrared data. Our sample is complete to optically thin, compact and UCHII regions driven by a zero age main sequence star of spectral type B0 or earlier embedded within a 1,000 Msun clump. In total we identify 213 compact and UCHII regions, associated with 170 clumps. Unambiguous kinematic distances are derived for these clumps and used to estimate their masses and physical sizes, as well as the Lyman continuum fluxes and sizes of their embedded HII regions. We find a clear lower envelope for the surface density of molecular clumps hosting massive star formation of 0.05 g cm^{-2}, which is consistent with a similar sample of clumps associated with 6.7 GHz masers. The mass of the most massive embedded stars is closely correlated with the ...

  4. Progress in Compact Toroid Experiments

    Energy Technology Data Exchange (ETDEWEB)

    Dolan, Thomas James

    2002-09-01

    The term "compact toroids" as used here means spherical tokamaks, spheromaks, and field reversed configurations, but not reversed field pinches. There are about 17 compact toroid experiments under construction or operating, with approximate parameters listed in Table 1.

  5. Magnetospheres of massive stars

    Science.gov (United States)

    Küker, M.

    We study the interaction of line-driven winds from massive stars with the magnetic field rooted in these stars by carrying out numerical simulations using the Nirvana MHD code in 2D in spherical polar coordinates. The code's adaptive mesh refinement feature allows high spatial resolution across the whole simulation box. We study both O and Wolf-Rayet stars for a range of magnetic field strengths from weak to strong as measured by the confinement parameter. For weak fields our simulations show that the initially dipolar field opens up far away from the star and a thin disk-like structure forms in the equatorial plane of the magnetic field. For stronger fields the disk is disrupted close to the stellar surface and closed field lines persist at low latitudes. For very strong fields a pronounced magnetosphere forms where the gas is forced to move along the field lines and eventually falls back to the stellar surface.

  6. massive excision of liver

    Directory of Open Access Journals (Sweden)

    Dong-liang LI

    2014-10-01

    Full Text Available Objective To observe the promotion effect of bone mesenchymal stem cells (BMSCs transplantation and mobilized bone marrow stem cells on the recovery of liver function and liver tissue regeneration after massive partial hepatectomy in rats. Methods The rats were randomly divided into four groups after massive partial hepatectomy (about 85%, namely massive hepatectomy group (control group, n=15, received massive hepatectomy only, G-CSF group [n=15, received rhG-CSF 150μg/(kg•d by intraperitoneal injection after the operation for 5 days], MSCs group [n=15, received 5ml suspension of MSCs (about 1.5×106 by tail vein injection after the operation], and G-CSF+MSCs group [n=14, received 1.5ml suspension of MSCs (about 1.5×106 by tail vein injection and rhG-CSF 150μg/(kg•d by intraperitoneal injection for 5 days after the operation]. The CD34+ cells in the peripheral blood of the rats were assessed by flow cytometry after G-CSF mobilization. Liver function tests including ALT, AST and ALB were performed on the 3rd and 9th day after surgery. All the rats were sacrificed and liver tissue was harvested for histopathological study. The expression of Ki-67 and BrdU positive cells in the liver were determined by immunohistochemistry. Results Flow cytometric results identified the isolated cells were MSCs. BMSCs in peripheral blood significantly increased in number after rhG-CSF mobilization, and reaching the maximum number on the 5th day. After mobilization for 3, 5 and 9 days, the positive CD34 cells in G-CSF group were 0.009%, 0.016%, 0.019% respectively, which were higher than those in control group. The level of albumin was significantly elevated in three treatment groups compared with control group on the 9th day after the hepatectomy (P<0.05 or P<0.01. The expression of Ki-67 (110.16±27.64, 103.57±33.90, 98.52±21.87 vs 72.39±27.04 cells and BrdU positive cells (17.96±5.57, 16.45±5.75, 16.66±5.11 vs 11.72±3.83 cells in three

  7. An Extended Star Formation History in an Ultra Compact Dwarf

    CERN Document Server

    Norris, Mark A; Faifer, Favio R; Kannappan, Sheila J; Forte, Juan Carlos; Bosch, Remco C E van den

    2015-01-01

    There has been significant controversy over the mechanisms responsible for forming compact stellar systems like ultra compact dwarfs (UCDs), with suggestions that UCDs are simply the high mass extension of the globular cluster (GC) population, or alternatively, the liberated nuclei of galaxies tidally stripped by larger companions. Definitive examples of UCDs formed by either route have been difficult to find, with only a handful of persuasive examples of stripped-nucleus type UCDs being known. In this paper we present very deep Gemini/GMOS spectroscopic observations of the suspected stripped nucleus UCD NGC 4546-UCD1 taken in good seeing conditions (< 0.7"). With these data we examine the spatially resolved kinematics and star formation history of this unusual object. We find no evidence of a rise in the central velocity dispersion of the UCD, suggesting that this UCD lacks a massive central black hole like those found in some other compact stellar systems, a conclusion confirmed by detailed dynamical mod...

  8. A massive graviton in topologically new massive gravity

    CERN Document Server

    Kim, Yong-Wan; Park, Young-Jai

    2013-01-01

    We investigate the topologically new massive gravity in three dimensions. It turns out that a single massive mode is propagating in the flat spacetime, comparing to the conformal Chern-Simons gravity which has no physically propagating degrees of freedom. Also we discuss the realization of the BMS/GCA correspondence.

  9. The United Nations Global Compact

    DEFF Research Database (Denmark)

    Rasche, Andreas; Waddock, Sandra; McIntosh, Malcolm

    2013-01-01

    This article reviews the interdisciplinary literature on the UN Global Compact. The review identifies three research perspectives, which scholars have used to study the UN Global Compact so far: a historical perspective discussing the Global Compact in the context of UN-business relations...

  10. Bovinos machos en pastoreo restringido complementados con caña de azúcar y maíz

    Directory of Open Access Journals (Sweden)

    Jorge Iraola

    2016-01-01

    Full Text Available Se evaluó el comportamiento productivo de bovinos machos en pastoreo restringido de gramíneas tropicales y leguminosas herbáceas complementados con energía. Se utilizaron 24 añojos mestizos lecheros durante el periodo seco. Se realizó análisis de varianza según diseño completamente aleatorizado con dos tratamientos. Se determinaron algunos indicadores productivos. Se encontró diferencia para la ganancia media diaria en el tratamiento con mayor inclusión de caña de azúcar. Se concluye que el pastoreo restringido de leguminosas herbáceas con complementación energética durante el periodo seco, garantizó adecuado comportamiento productivo y ganancias a favor del tratamiento con mayor nivel de caña de azúcar.

  11. Compact fusion reactors

    CERN Document Server

    CERN. Geneva

    2015-01-01

    Fusion research is currently to a large extent focused on tokamak (ITER) and inertial confinement (NIF) research. In addition to these large international or national efforts there are private companies performing fusion research using much smaller devices than ITER or NIF. The attempt to achieve fusion energy production through relatively small and compact devices compared to tokamaks decreases the costs and building time of the reactors and this has allowed some private companies to enter the field, like EMC2, General Fusion, Helion Energy, Lawrenceville Plasma Physics and Lockheed Martin. Some of these companies are trying to demonstrate net energy production within the next few years. If they are successful their next step is to attempt to commercialize their technology. In this presentation an overview of compact fusion reactor concepts is given.

  12. Compact Spreader Schemes

    Energy Technology Data Exchange (ETDEWEB)

    Placidi, M.; Jung, J. -Y.; Ratti, A.; Sun, C.

    2014-07-25

    This paper describes beam distribution schemes adopting a novel implementation based on low amplitude vertical deflections combined with horizontal ones generated by Lambertson-type septum magnets. This scheme offers substantial compactness in the longitudinal layouts of the beam lines and increased flexibility for beam delivery of multiple beam lines on a shot-to-shot basis. Fast kickers (FK) or transverse electric field RF Deflectors (RFD) provide the low amplitude deflections. Initially proposed at the Stanford Linear Accelerator Center (SLAC) as tools for beam diagnostics and more recently adopted for multiline beam pattern schemes, RFDs offer repetition capabilities and a likely better amplitude reproducibility when compared to FKs, which, in turn, offer more modest financial involvements both in construction and operation. Both solutions represent an ideal approach for the design of compact beam distribution systems resulting in space and cost savings while preserving flexibility and beam quality.

  13. Compact fiber optic accelerometer

    Institute of Scientific and Technical Information of China (English)

    Feng Peng; Jun Yang; Bing Wu; Yonggui Yuan; Xingliang Li; Ai Zhou; Libo Yuan

    2012-01-01

    A compact fiber optic accelerometer based on a Michelson interferometer is proposed and demonstrated.In the proposed system,the sensing element consists of two single-mode fibers glued together by epoxy,which then act as a simple supported beam.By demodulating the optical phase shift,the acceleration is determined as proportional to the force applied on the central position of the two single-mode fibers.This simple model is able to calculate the sensitivity and the resonant frequency of the compact accelerometer.The experimental results show that the sensitivity and the resonant frequency of the accelerometer are 0.42 rad/g and 600 Hz,respectively.

  14. Analysis of laboratory compaction methods of roller compacted concrete

    Science.gov (United States)

    Trtík, Tomáš; Chylík, Roman; Bílý, Petr; Fládr, Josef

    2017-09-01

    Roller-Compacted Concrete (RCC) is an ordinary concrete poured and compacted with machines typically used for laying of asphalt road layers. One of the problems connected with this technology is preparation of representative samples in the laboratory. The aim of this work was to analyse two methods of preparation of RCC laboratory samples with bulk density as the comparative parameter. The first method used dynamic compaction by pneumatic hammer. The second method of compaction had a static character. The specimens were loaded by precisely defined force in laboratory loading machine to create the same conditions as during static rolling (in the Czech Republic, only static rolling is commonly used). Bulk densities obtained by the two compaction methods were compared with core drills extracted from real RCC structure. The results have shown that the samples produced by pneumatic hammer tend to overestimate the bulk density of the material. For both compaction methods, immediate bearing index test was performed to verify the quality of compaction. A fundamental difference between static and dynamic compaction was identified. In static compaction, initial resistance to penetration of the mandrel was higher, after exceeding certain limit the resistance was constant. This means that the samples were well compacted just on the surface. Specimens made by pneumatic hammer actively resisted throughout the test, the whole volume was uniformly compacted.

  15. Massive Gravity in Three Dimensions

    NARCIS (Netherlands)

    Bergshoeff, Eric A.; Hohm, Olaf; Townsend, Paul K.

    2009-01-01

    A particular higher-derivative extension of the Einstein-Hilbert action in three spacetime dimensions is shown to be equivalent at the linearized level to the (unitary) Pauli-Fierz action for a massive spin-2 field. A more general model, which also includes "topologically-massive" gravity as a speci

  16. Gravitational lensing by compact objects within plasma

    CERN Document Server

    Rogers, Adam

    2016-01-01

    Frequency-dependent gravitational lens effects are found for trajectories of electromagnetic rays passing through a distribution of plasma near a massive object. Ray propagation through plasma adds extra terms to the equations of motion that depend on the plasma refractive index. For low-frequency rays these refractive effects can dominate, turning the gravitational lens into a mirror. While light rays behave like particles with an effective mass given by the plasma frequency in a medium with constant density, an inhomogeneous plasma introduces more complicated behavior even for the spherically symmetric case. As a physical example, the pulse profile of a compact object sheathed in a dense plasma is examined, which introduces dramatic frequency-dependent shifts from the behavior in vacuum.

  17. New Results on Charged Compact Boson Stars

    CERN Document Server

    Kumar, Sanjeev; Kulshreshtha, Daya Shankar

    2016-01-01

    In this work we present some new results which we have obtained in a study of the phase diagram of charged compact boson stars in the theory involving massive complex scalar fields coupled to the U(1) gauge field and gravity in a conical potential in the presence of a cosmological constant $\\Lambda$ which we treat as a free parameter taking positive and negative values and thereby allowing us to study the theory in the de Sitter and Anti de Sitter spaces respectively. In our studies, we obtain four bifurcation points (possibility of more bifurcation points being not ruled out) in the de Sitter region. We present a detailed discussion of the various regions in our phase diagram with respect to four bifurcation points. Our theory is seen to have rich physics in a particular domain for positive values of $\\Lambda$ which is consistent with the accelerated expansion of the universe.

  18. How can young massive clusters reach their present-day sizes?

    Science.gov (United States)

    Banerjee, Sambaran; Kroupa, Pavel

    2017-01-01

    Context. The classic question of how young massive star clusters attain the shapes and sizes, as we find them today, is still a difficult one. Both observational and computational studies of star-forming massive molecular gas clouds suggest that massive cluster formation is primarily triggered along the small-scale (≲0.3 pc) filamentary substructures within the clouds. Aims: The present study investigates the possible ways in which a filament-like, compact, massive star cluster (effective radius 0.1-0.3 pc) can expand more than 10 times, still remaining massive enough (≳ 104M⊙) to become the young massive star cluster that we observe today. Methods: To this end, model massive clusters (initially 104-105M⊙) are evolved using Sverre Aarseth's state-of-the-art N-body code NBODY7. Apart from the accurate calculation of two-body relaxation of the constituent stars, these evolutionary models take into account stellar-evolutionary mass loss and dynamical energy injection due to massive, tight primordial binaries and stellar-remnant black holes and neutron stars. These calculations also include a solar-neighbourhood-like external tidal field. All the computed clusters expand with time, and their sizes (effective radii) are compared with those observed for young massive clusters (≲ 100 Myr) in the Milky Way and other nearby galaxies. Results: In this study, it is found that beginning from the above compact sizes, a star cluster cannot expand on its own, i.e., due to two-body relaxation, stellar mass loss, and dynamical heating by primordial binaries and compact stars up to the observed sizes of young massive clusters; star clusters always remain much more compact than the observed ones. Conclusions: This calls for additional mechanisms that boost the expansion of a massive cluster after its assembly. Using further N-body calculations, it is shown that a substantial residual gas expulsion with ≈ 30% star formation efficiency can indeed swell the newborn embedded

  19. Towards a census of supercompact massive galaxies in the Kilo Degree Survey

    NARCIS (Netherlands)

    Tortora, C.; La Barbera, F.; Napolitano, N. R.; Roy, N.; Radovich, M.; Cavuoti, S.; Brescia, M.; Longo, G.; Getman, F.; Capaccioli, M.; Grado, A.; Kuijken, K. H.; de Jong, J. T. A.; Mc Farland, J.; Puddu, E.

    2016-01-01

    The abundance of compact, massive, early-type galaxies (ETGs) provides important constraints to galaxy formation scenarios. Thanks to the area covered, depth, excellent spatial resolution and seeing, the ESO Public optical Kilo Degree Survey (KiDS), carried out with the VLT Survey Telescope, offers

  20. Two-loop RG functions of the massive φ4 field theory in general dimensions

    Directory of Open Access Journals (Sweden)

    M.A. Shpot

    2010-01-01

    Full Text Available Two-loop Feynman integrals of the massive φ4d field theory are explicitly obtained for generic space dimensions d. Corresponding renormalization-group functions are expressed in a compact form in terms of Gauss hypergeometric functions. A number of interesting and useful relations are given for these integrals as well as for several special mathematical functions and constants.

  1. Towards a census of supercompact massive galaxies in the Kilo Degree Survey

    NARCIS (Netherlands)

    Tortora, C.; La Barbera, F.; Napolitano, N. R.; Roy, N.; Radovich, M.; Cavuoti, S.; Brescia, M.; Longo, G.; Getman, F.; Capaccioli, M.; Grado, A.; Kuijken, K. H.; de Jong, J. T. A.; Mc Farland, J.; Puddu, E.

    2016-01-01

    The abundance of compact, massive, early-type galaxies (ETGs) provides important constraints to galaxy formation scenarios. Thanks to the area covered, depth, excellent spatial resolution and seeing, the ESO Public optical Kilo Degree Survey (KiDS), carried out with the VLT Survey Telescope, offers

  2. THE CASE AGAINST A MASSIVE BLACK-HOLE AT THE GALACTIC-CENTER

    NARCIS (Netherlands)

    SANDERS, RH

    1992-01-01

    MANY of the compact near-infrared sources observed in the central parsec of our Galaxy have been shown to be very massive, luminous blue stars with strong helium lines and fast winds, perhaps similar to Wolf-Rayet stars1-3; and the complex near-infrared source IRS16, which appears to be the central

  3. Hydraulic conductivity of compacted zeolites.

    Science.gov (United States)

    Oren, A Hakan; Ozdamar, Tuğçe

    2013-06-01

    Hydraulic conductivities of compacted zeolites were investigated as a function of compaction water content and zeolite particle size. Initially, the compaction characteristics of zeolites were determined. The compaction test results showed that maximum dry unit weight (γ(dmax)) of fine zeolite was greater than that of granular zeolites. The γ(dmax) of compacted zeolites was between 1.01 and 1.17 Mg m(-3) and optimum water content (w(opt)) was between 38% and 53%. Regardless of zeolite particle size, compacted zeolites had low γ(dmax) and high w(opt) when compared with compacted natural soils. Then, hydraulic conductivity tests were run on compacted zeolites. The hydraulic conductivity values were within the range of 2.0 × 10(-3) cm s(-1) to 1.1 × 10(-7) cm s(-1). Hydraulic conductivity of all compacted zeolites decreased almost 50 times as the water content increased. It is noteworthy that hydraulic conductivity of compacted zeolite was strongly dependent on the zeolite particle size. The hydraulic conductivity decreased almost three orders of magnitude up to 39% fine content; then, it remained almost unchanged beyond 39%. Only one report was found in the literature on the hydraulic conductivity of compacted zeolite, which is in agreement with the findings of this study.

  4. Massive gauge-flation

    Science.gov (United States)

    Nieto, Carlos M.; Rodríguez, Yeinzon

    2016-06-01

    Gauge-flation model at zeroth-order in cosmological perturbation theory offers an interesting scenario for realizing inflation within a particle physics context, allowing us to investigate interesting possible connections between inflation and the subsequent evolution of the Universe. Difficulties, however, arise at the perturbative level, thus motivating a modification of the original model. In order to agree with the latest Planck observations, we modify the model such that the new dynamics can produce a relation between the spectral index ns and the tensor-to-scalar ratio r allowed by the data. By including an identical mass term for each of the fields of the system, we find interesting dynamics leading to slow-roll inflation of the right length. The presence of the mass term has the potential to modify the ns versus r relation so as to agree with the data. As a first step, we study the model at zeroth-order in cosmological perturbation theory, finding the conditions required for slow-roll inflation and the number of e-foldings of inflation. Numerical solutions are used to explore the impact of the mass term. We conclude that the massive version of gauge-flation offers a viable inflationary model.

  5. Compact star forming galaxies as the progenitors of compact quiescent galaxies: Clustering result

    Science.gov (United States)

    Lin, Xiaozhi; Fan, Lulu; Kong, Xu; Fang, Guanwen

    2017-02-01

    We present a measurement of the spatial clustering of massive compact galaxies at 1.2 ≤ z ≤ 3 in CANDELS/3D-HST fields. We obtain the correlation length for compact quiescent galaxies (cQGs) at z ∼ 1.6 of r0 = 7.1-2.6+2.3 h-1 Mpc and compact star forming galaxies (cSFGs) at z ∼ 2.5 of r0 = 7.7-2.9+2.7 h-1 Mpc assuming a power-law slope γ = 1.8 . The characteristic dark matter halo masses MH of cQGs at z ∼ 1.6 and cSFGs at z ∼ 2.5 are ∼ 7.1 ×1012h-1M⊙ and ∼ 4.4 ×1012h-1M⊙ , respectively. Our clustering result suggests that cQGs at z ∼ 1.6 are possibly the progenitors of local luminous ETGs and the descendants of cSFGs and SMGs at z > 2. Thus an evolutionary connection involving SMGs, cSFGs, QSOs, cQGs and local luminous ETGs has been indicated by our clustering result.

  6. Compact star forming galaxies as the progenitors of compact quiescent galaxies: clustering result

    CERN Document Server

    Lin, Xiaozhi; Kong, Xu; Fang, Guanwen

    2016-01-01

    We present a measurement of the spatial clustering of massive compact galaxies at $1.2\\le z \\le 3$ in CANDELS/3D-HST fields. We obtain the correlation length for compact quiescent galaxies (cQGs) at $z\\sim1.6$ of $r_{0}=7.1_{-2.6}^{+2.3}\\ h^{-1}Mpc$ and compact star forming galaxies (cSFGs) at $z\\sim2.5$ of $r_{0}=7.7_{-2.9}^{+2.7}\\ h^{-1}Mpc$ assuming a power-law slope $\\gamma =1.8$. The characteristic dark matter halo masses $M_H$ of cQGs at $z\\sim1.6$ and cSFGs at $z\\sim2.5$ are $\\sim7.1\\times 10^{12}\\ h^{-1} M_\\odot$ and $\\sim4.4\\times10^{12}\\ h^{-1} M_\\odot$, respectively. Our clustering result suggests that cQGs at $z\\sim1.6$ are possibly the progenitors of local luminous ETGs and the descendants of cSFGs and SMGs at $z>2$. Thus an evolutionary connection involving SMGs, cSFGs, QSOs, cQGs and local luminous ETGs has been indicated by our clustering result.

  7. EVIDENCE FOR (AND AGAINST) PROGENITOR BIAS IN THE SIZE GROWTH OF COMPACT RED GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Keating, Stephanie K.; Abraham, Roberto G. [Department of Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, ON M5S 3H4 (Canada); Schiavon, Ricardo [Gemini Observatory, 670 North A' ohoku Place, Hilo, HI 96720 (United States); Graves, Genevieve [Department of Astronomy, University of California, Berkeley, CA 94720 (United States); Damjanov, Ivana [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Yan, Renbin [Department of Physics and Astronomy, University of Kentucky, 505 Rose Street, Lexington, KY 40506-0055 (United States); Newman, Jeffrey [Department of Physics and Astronomy, University of Pittsburgh, 3941 O' Hara Street, Pittsburgh, PA 15260 (United States); Simard, Luc [National Research Council of Canada, 5071 West Saanich Road, Victoria, BC V9E 2E7 (Canada)

    2015-01-01

    Most massive, passive galaxies are compact at high redshifts, but similarly compact massive galaxies are rare in the local universe. The most common interpretation of this phenomenon is that massive galaxies have grown in size by a factor of about five since redshift z = 2. An alternative explanation is that recently quenched massive galaxies are larger (a {sup p}rogenitor bias{sup )}. In this paper, we explore the importance of progenitor bias by looking for systematic differences in the stellar populations of compact early-type galaxies in the DEEP2 survey as a function of size. Our analysis is based on applying the statistical technique of bootstrap resampling to constrain differences in the median ages of our samples and to begin to characterize the distribution of stellar populations in our co-added spectra. The light-weighted ages of compact early-type galaxies at redshifts 0.5 < z < 1.4 are compared to those of a control sample of larger galaxies at similar redshifts. We find that massive compact early-type galaxies selected on the basis of red color and high bulge-to-total ratio are younger than similarly selected larger galaxies, suggesting that size growth in these objects is not driven mainly by progenitor bias, and that individual galaxies grow as their stellar populations age. However, compact early-type galaxies selected on the basis of image smoothness and high bulge-to-total ratio are older than a control sample of larger galaxies. Progenitor bias will play a significant role in defining the apparent size changes of early-type galaxies if they are selected on the basis of the smoothness of their light distributions.

  8. Compact LINAC for deuterons

    Energy Technology Data Exchange (ETDEWEB)

    Kurennoy, S S [Los Alamos National Laboratory; O' Hara, J F [Los Alamos National Laboratory; Rybarcyk, L J [Los Alamos National Laboratory

    2008-01-01

    We are developing a compact deuteron-beam accelerator up to the deuteron energy of a few MeV based on room-temperature inter-digital H-mode (IH) accelerating structures with the transverse beam focusing using permanent-magnet quadrupoles (PMQ). Combining electromagnetic 3-D modeling with beam dynamics simulations and thermal-stress analysis, we show that IHPMQ structures provide very efficient and practical accelerators for light-ion beams of considerable currents at the beam velocities around a few percent of the speed of light. IH-structures with PMQ focusing following a short RFQ can also be beneficial in the front end of ion linacs.

  9. Compact synchrotron light sources

    CERN Document Server

    Weihreter, Ernst

    1996-01-01

    This book covers a new niche in circular accelerator design, motivated by the promising industrial prospects of recent micromanufacturing methods - X-ray lithography, synchrotron radiation-based micromachining and microanalysis techniques. It describes the basic concepts and the essential challenges for the development of compact synchrotron radiation sources from an accelerator designer's point of view and gives an outline of the actual state of the art. The volume is intended as an introduction and as a reference for physicists, engineers and managers involved in this rapidly developing fiel

  10. Compact Q-balls

    CERN Document Server

    Bazeia, D; Marques, M A; Menezes, R; da Rocha, R

    2016-01-01

    In this work we deal with non-topological solutions of the Q-ball type in two space-time dimensions, in models described by a single complex scalar field that engenders global symmetry. The main novelty is the presence of stable Q-balls solutions that live in a compact interval of the real line and appear from a family of models controlled by two distinct parameters. We find analytical solutions and study their charge and energy, and show how to control the parameters to make the Q-balls classically and quantum mechanically stable.

  11. The Destructive Birth of Massive Stars and Massive Star Clusters

    Science.gov (United States)

    Rosen, Anna; Krumholz, Mark; McKee, Christopher F.; Klein, Richard I.; Ramirez-Ruiz, Enrico

    2017-01-01

    Massive stars play an essential role in the Universe. They are rare, yet the energy and momentum they inject into the interstellar medium with their intense radiation fields dwarfs the contribution by their vastly more numerous low-mass cousins. Previous theoretical and observational studies have concluded that the feedback associated with massive stars' radiation fields is the dominant mechanism regulating massive star and massive star cluster (MSC) formation. Therefore detailed simulation of the formation of massive stars and MSCs, which host hundreds to thousands of massive stars, requires an accurate treatment of radiation. For this purpose, we have developed a new, highly accurate hybrid radiation algorithm that properly treats the absorption of the direct radiation field from stars and the re-emission and processing by interstellar dust. We use our new tool to perform a suite of three-dimensional radiation-hydrodynamic simulations of the formation of massive stars and MSCs. For individual massive stellar systems, we simulate the collapse of massive pre-stellar cores with laminar and turbulent initial conditions and properly resolve regions where we expect instabilities to grow. We find that mass is channeled to the massive stellar system via gravitational and Rayleigh-Taylor (RT) instabilities. For laminar initial conditions, proper treatment of the direct radiation field produces later onset of RT instability, but does not suppress it entirely provided the edges of the radiation-dominated bubbles are adequately resolved. RT instabilities arise immediately for turbulent pre-stellar cores because the initial turbulence seeds the instabilities. To model MSC formation, we simulate the collapse of a dense, turbulent, magnetized Mcl = 106 M⊙ molecular cloud. We find that the influence of the magnetic pressure and radiative feedback slows down star formation. Furthermore, we find that star formation is suppressed along dense filaments where the magnetic field is

  12. Gauge Model with Massive Gravitons

    Institute of Scientific and Technical Information of China (English)

    WU Ning

    2003-01-01

    Gauge theory of gravity is formulated based on principle of local gauge invariance. Because the model hasstrict local gravitational gauge symmetry, and gauge theory of gravity is a perturbatively renormalizable quantum model.However, in the original model, all gauge gravitons are massless. We want to ask whether there exist massive gravitonsin Nature. In this paper, we will propose a gauge model with massive gravitons. The mass term of gravitational gaugefield is introduced into the theory without violating the strict local gravitational gauge symmetry. Massive gravitons canbe considered to be possible origin of dark energy and dark matter in the Universe.

  13. A not so massive cluster hosting a very massive star

    CERN Document Server

    Alegría, S Ramírez; Borissova, J; Kurtev, R; Navarro, C; Kuhn, M; Carballo-Bello, J A

    2015-01-01

    We present the first physical characterization of the young open cluster VVV CL041. We spectroscopically observed the cluster main-sequence stellar population and a very-massive star candidate: WR62-2. CMFGEN modeling to our near-infrared spectra indicates that WR62-2 is a very luminous (10$^{6.4\\pm0.2} L_{\\odot}$) and massive ($\\sim80 M_{\\odot}$) star.

  14. Improving compact gravity inversion using new weighting functions

    Science.gov (United States)

    Ghalehnoee, Mohammad Hossein; Ansari, Abdolhamid; Ghorbani, Ahmad

    2017-01-01

    We have developed a method to estimate the geometry, location and densities of anomalies coming from 2-D gravity data based on compact gravity inversion technique. Compact gravity inversion is simple, fast and user friendly but severely depends on the number of model parameters, that is, by increasing the model parameters, the anomalies tend to concentrate near the surface. To overcome this ambiguity new weighting functions based on density contrast, depth, and compactness models have been introduced. Variable compactness factors have been defined here to get either a sharp or a smooth model based on the depth of the source or existence of prior information. Depth weighting derived from one station of gravity data whereas the effect of gravity data is 2-D and 3-D. To compensate this limitation an innovating weighting function namely kernel function has been introduced which multiplies with weight and compactness matrixes to yield a general model weighting function. The method is tested using three different sets of synthetic examples: a body at various depths (20, 40, 80 and 140 m), two bodies at the same depth but various distances to estimate lateral resolution and three bodies with negative and positive density contrast in different depths. The method is also applied to three real gravity data of Woodlawn massive sulphide body, sulphides mineralization of British Colombia and iron ore body of Missouri. The method produces solutions consistent with the known geologic attributes of the gravity sources, illustrating its potential practicality.

  15. Improving compact gravity inversion based on new weighting functions

    Science.gov (United States)

    Ghalehnoee, Mohammad Hossein; Ansari, Abdolhamid; Ghorbani, Ahmad

    2016-11-01

    We have developed a method to estimate the geometry, location and densities of anomalies coming from two-dimensional gravity data based on compact gravity inversion technique. Compact gravity inversion is simple, fast and user friendly but severely depends on the number of model parameters, i.e. by increasing the model parameters, the anomalies tend to concentrate near the surface. To overcome this ambiguity new weighting functions based on density contrast, depth, and compactness models have been introduced. Variable compactness factors have been defined here to get either a sharp or a smooth model based on the depth of the source or existence of prior information. Depth weighting derived from one station of gravity data whereas the effect of gravity data is two- and three-dimensional. To compensate this limitation an innovating weighting function namely kernel function has been introduced which multiplies with weight and compactness matrixes to yield a general model weighting function. The method is tested using three different sets of synthetic examples: a body at various depths (20, 40, 80 and 140 m), two bodies at the same depth but various distances to estimate lateral resolution and three bodies with negative and positive density contrast in different depths. The method is also applied to three real gravity data of Woodlawn massive sulfide body, sulfides mineralization of British Colombia and iron ore body of Missouri. The method produces solutions consistent with the known geologic attributes of the gravity sources, illustrating its potential practicality.

  16. Lacunarity for compact groups.

    Science.gov (United States)

    Edwards, R E; Hewitt, E; Ross, K A

    1971-01-01

    Let G be a compact Abelian group with character group X. A subset Delta of X is called a [unk](q) set (1 < q < infinity) if for all trigonometric polynomials f = [unk](k=1) (n) alpha(k)chi(k) (chi(1),...,chi(n) [unk] Delta) an inequality parallelf parallel(q) [unk] [unk] parallelf parallel(1) obtains, where [unk] is a positive constant depending only on Delta. The subset Delta is called a Sidon set if every bounded function on Delta can be matched by a Fourier-Stieltjes transform. It is known that every Sidon set is a [unk](q) set for all q. For G = T, X = Z, Rudin (J. Math. Mech., 9, 203 (1960)) has found a set that is [unk](q) for all q but not Sidon. We extend this result to all infinite compact Abelian groups G: the character group X contains a subset Delta that is [unk](q) for all q, 1 < q < infinity, but Delta is not a Sidon set.

  17. A compact SADM family

    Science.gov (United States)

    Barbet, Vincent; Le Quintrec, Cyrille; Jeandot, Xavier; Chaix, Alain; Grain, Eric; Roux, Jerome

    2005-07-01

    Alcatel Space has developed a new SADM family driven by cost, modularity, mass and performances. The modularity concept is based on separating the rotation drive function from the electrical transfer function. The drive actuator has been designed for various applications where pointing and reliability is needed. It can be associated with high dissipative rotary devices (SA collectors, RF joints..). The design goal was to minimize the number of parts in order to reach the most simple and compact mechanism. Mass reduction was achieved by reducing as much as possible the load path between the Solar Array interface and the spacecraft interface. Following these guidelines, the drive actuator was developed and qualified on ATV SADM (part od Alcatel Space Solar Array Drive Sub System for ATV). Further more a high power integrated collector was qualified inside the SADM for Geo-stationary telecom satellite (SPACEBUS platforms). Fine thermal and mechanical modeling was necessary to predict SADM behaviors for the numerous thermal environments over the missions (steady and transient cases). These modeling were well correlated through mechanical and thermal balances qualification tests. The challenging approach of thermal dissipation in a compact design leads to a family of 3 SADM capabilities form 2kW up to 15kW per SADM weighing less than 4.5 kg each.

  18. Compact electrostatic comb actuator

    Science.gov (United States)

    Rodgers, M. Steven; Burg, Michael S.; Jensen, Brian D.; Miller, Samuel L.; Barnes, Stephen M.

    2000-01-01

    A compact electrostatic comb actuator is disclosed for microelectromechanical (MEM) applications. The actuator is based upon a plurality of meshed electrostatic combs, some of which are stationary and others of which are moveable. One or more restoring springs are fabricated within an outline of the electrostatic combs (i.e. superposed with the moveable electrostatic combs) to considerably reduce the space required for the actuator. Additionally, a truss structure is provided to support the moveable electrostatic combs and prevent bending or distortion of these combs due to unbalanced electrostatic forces or external loading. The truss structure formed about the moveable electrostatic combs allows the spacing between the interdigitated fingers of the combs to be reduced to about one micron or less, thereby substantially increasing the number of active fingers which can be provided in a given area. Finally, electrostatic shields can be used in the actuator to substantially reduce unwanted electrostatic fields to further improve performance of the device. As a result, the compact electrostatic comb actuator of the present invention occupies only a fraction of the space required for conventional electrostatic comb actuators, while providing a substantial increase in the available drive force (up to one-hundred times).

  19. Compaction of Titanium Powders

    Energy Technology Data Exchange (ETDEWEB)

    Gerdemann, Stephen,J; Jablonski, Paul, J

    2011-05-01

    Accurate modeling of powder densification has been an area of active research for more than 60 years. The earliest efforts were focused on linearization of the data because computers were not readily available to assist with curve-fitting methods. In this work, eight different titanium powders (three different sizes of sponge fines<150 {micro}m,<75 {micro}m, and<45 {micro}m; two different sizes of a hydride-dehydride [HDH]<75 {micro}m and<45 {micro}m; an atomized powder; a commercially pure [CP] Ti powder from International Titanium Powder [ITP]; and a Ti 6 4 alloy powder) were cold pressed in a single-acting die instrumented to collect stress and deformation data during compaction. From these data, the density of each compact was calculated and then plotted as a function of pressure. The results show that densification of all the powders, regardless of particle size, shape, or chemistry, can be modeled accurately as the sum of an initial density plus the sum of a rearrangement term and a work-hardening term. These last two terms are found to be a function of applied pressure and take the form of an exponential rise.

  20. Infrared color selection of massive galaxies at z > 3

    CERN Document Server

    Wang, T; Schreiber, C; Pannella, M; Shu, X; Willner, S P; Ashby, M L N; Huang, J -S; Fontana, A; Dekel, A; Daddi, E; Ferguson, H C; Dunlop, J; Ciesla, L; Koekemoer, A M; Giavalisco, M; Boutsia, K; Finkelstein, S; Juneau, S; Barro, G; Koo, D C; Michałowski, M J; Orellana, G; Lu, Y; Castellano, M; Bourne, N; Buitrago, F; Santini, P; Faber, S M; Hathi, N; Lucas, R A; Pérez-González, P G

    2016-01-01

    We introduce a new color-selection technique to identify high-redshift, massive galaxies that are systematically missed by Lyman-break selection. The new selection is based on the H_{160} and IRAC 4.5um bands, specifically H - [4.5] > 2.25 mag. These galaxies, dubbed "HIEROs", include two major populations that can be separated with an additional J - H color. The populations are massive and dusty star-forming galaxies at z > 3 (JH-blue) and extremely dusty galaxies at z 3) HIEROs, which have a median photometric redshift z ~4.4 and stellar massM_{*}~10^{10.6} Msun, and are much fainter in the rest-frame UV than similarly massive Lyman-break galaxies (LBGs). Their star formation rates (SFRs) reaches ~240 Msun yr^{-1} leading to a specific SFR, sSFR ~4.2 Gyr^{-1}, suggesting that the sSFRs for massive galaxies continue to grow at z > 2 but at a lower growth rate than from z=0 to z=2. With a median half-light radius of 2 kpc, including ~20% as compact as quiescent galaxies at similar redshifts, JH-blue HIEROs r...

  1. Produção de sementes macho-estéreis em arroz Male-sterile rice seed production

    Directory of Open Access Journals (Sweden)

    Claudio Bragantini

    2001-02-01

    Full Text Available A obtenção comercial de sementes da linhagem macho-estéril é uma das limitações para viabilizar a produção de híbridos de arroz (Oryza sativa L.. Este trabalho buscou estudar três proporções entre a linhagem macho-estéril (linhagem A e a mantenedora (linhagem B. As proporções estudadas foram 8:4, 10:2 e 14:4. As características avaliadas para determinar qual das proporções apresenta maior potencial foram: número e porcentagem de grãos cheios por panículas, e número de grãos de pólen por unidade de área. A proporção 8:4 produziu maior porcentagem de grãos cheios por panícula que as outras duas, mas, proporcionalmente, ocupa maior área física com a linhagem B no campo. Foram observadas diferenças estatísticas na porcentagem de grãos cheios entre as amostras coletadas nas várias fileiras da linhagem A (diferentes distâncias da fonte polinizadora, e observou-se uma influência marcante com relação à direção predominante dos ventos. O número de grãos de pólen foi igual para todas as relações e distâncias da fonte de pólen; por isso, não foi o fator determinante das diferenças observadas em porcentagem de grãos cheios por panícula. Os resultados permitiram concluir que a proporção 10:2 é a de maior potencial para a produção comercial de sementes da linhagem macho-estéril.Commercial male-sterile rice (Oryza sativa L. seed production is one of the limitations to allow large scale hybrid seed production. This work studied three ratios between male-sterile line (A line and maintainer (B line. The A:B ratios used in the study were: 8:4, 10:2 and 14:4. The evaluated traits to determine which ratio is more suitable were: number and percentage of filled grains per panicle and number of pollen grains per unit area. The 8:4 ratio produced statistically significant higher percentage of filled grains per panicle than the other two, but proportionally it requires more field area for the B line. Statistical

  2. How can young massive clusters reach their present-day sizes?

    CERN Document Server

    Banerjee, Sambaran

    2015-01-01

    The classic question that how young massive star clusters attain their shapes and sizes, as we find them today, remains to be a challenge. Both observational and computational studies of star-forming massive molecular gas clouds infer that massive cluster formation is primarily triggered along the small-scale ($\\lesssim0.3$ pc) filamentary substructures within the clouds. The present study is intended to investigate the possible ways in which a filament-like-compact, massive star cluster (effective radius 0.1-0.3 pc) can expand $\\gtrsim10$ times, still remaining massive enough ($\\gtrsim10^4 M_\\odot$), to become a young massive star cluster, as we observe today. To that end, model massive clusters (of initially $10^4 M_\\odot-10^5 M_\\odot$) are evolved using Sverre Aarseth's state-of-the-art N-body code NBODY7. All the computed clusters expand with time, whose sizes (effective radii) are compared with those observed for young massive clusters, of age $\\lesssim100$ Myr, in the Milky Way and other nearby galaxies...

  3. METHYL CYANIDE OBSERVATIONS TOWARD MASSIVE PROTOSTARS

    Energy Technology Data Exchange (ETDEWEB)

    Rosero, V.; Hofner, P. [Physics Department, New Mexico Tech, 801 Leroy Place, Socorro, NM 87801 (United States); Kurtz, S. [Centro de Radioastronomia y Astrofisica, Universidad Nacional Autonoma de Mexico, Morelia 58090 (Mexico); Bieging, J. [Department of Astronomy and Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Araya, E. D. [Physics Department, Western Illinois University, 1 University Circle, Macomb, IL 61455 (United States)

    2013-07-01

    We report the results of a survey in the CH{sub 3}CN J = 12 {yields} 11 transition toward a sample of massive proto-stellar candidates. The observations were carried out with the 10 m Submillimeter Telescope on Mount Graham, AZ. We detected this molecular line in 9 out of 21 observed sources. In six cases this is the first detection of this transition. We also obtained full beam sampled cross-scans for five sources which show that the lower K-components can be extended on the arcminute angular scale. The higher K-components, however, are always found to be compact with respect to our 36'' beam. A Boltzmann population diagram analysis of the central spectra indicates CH{sub 3}CN column densities of about 10{sup 14} cm{sup -2}, and rotational temperatures above 50 K, which confirms these sources as hot molecular cores. Independent fits to line velocity and width for the individual K-components resulted in the detection of an increasing blueshift with increasing line excitation for four sources. Comparison with mid-infrared (mid-IR) images from the SPITZER GLIMPSE/IRAC archive for six sources show that the CH{sub 3}CN emission is generally coincident with a bright mid-IR source. Our data clearly show that the CH{sub 3}CN J = 12 {yields} 11 transition is a good probe of the hot molecular gas near massive protostars, and provide the basis for future interferometric studies.

  4. On stable compact minimal submanifolds

    CERN Document Server

    Torralbo, Francisco

    2010-01-01

    Stable compact minimal submanifolds of the product of a sphere and any Riemannian manifold are classified whenever the dimension of the sphere is at least three. The complete classification of the stable compact minimal submanifolds of the product of two spheres is obtained. Also, it is proved that the only stable compact minimal surfaces of the product of a 2-sphere and any Riemann surface are the complex ones.

  5. Características seminales del macho cabrío Serrano Transmontano (Semen characteristics of the Serrano Transmontano buck

    Directory of Open Access Journals (Sweden)

    Almendra, L.

    2005-12-01

    Full Text Available Las características de producción espermática constituyen uno de los factores más importantes del desarrollo de programas de inseminación artificial. El objetivo del presente trabajo consistió en el estudio de algunas de las características del semen producido a lo largo del año por machos cabríos de la raza Serrana Ecotipo Transmontano. Fueron estudiados 8 animales (4 adultos datando la primera recogida de semen con más de 18 meses y 4 machos jóvenes con 6-10 meses de edad. Las variables analizadas fueron el volumen (n=378; 0,859 ± 0,337 ml, la concentración (n=227; 4,791 x 106 ± 1,694 espermatozóides/ml, la motilidad masal (n=314; 3,7 ± 0,8 y la motilidad individual (n=308; 69,2 ± 14,1 %. Se observó una influencia muy significativa (P0,05. A pesar de las variaciones observadas, las características seminales (volumen de eyaculado y motilidad espermática, no parecen constituir un factor adverso en la utilización del semen en inseminación artificial, cualquiera que sea la época del año. Sperm production is one of the most important factors for the development of artificial insemination programs. The objective of this study was the evaluation of some characteristics of semen produced throughout the year by bucks of the breed Serrana ecotype Transmontano. Eight male goats were studied (4 adult males, more than 18 months old at the first semen collection and 4 young males 6-10 months old. Variables studied were volume of ejaculate (n=378; 0.859 ± 0.337 ml, sperm number (n=227; 4.791 x 106 ± 1.694 sperm cells/ml, sperm mass motility (n=314; 3.7 ± 0.8 and sperm individual motility (n=308; 69.2 ± 14.1 %. Age of males influenced significantly (P0,05. In spite of the observed variations, the seminal characteristics (volume of the ejaculate and sperm motility don't seem to constitute an adverse factor to the use of the semen in artificial insemination in any season throughout the year

  6. Desenvolvimento corporal e testicular em machos de codornas de corte e de postura de 25 a 360 dias

    Directory of Open Access Journals (Sweden)

    Tatiana C. Santos

    2012-11-01

    Full Text Available Codornas do tipo carne e tipo ovos foram analisadas para determinar o desenvolvimento reprodutivo, a puberdade e o início da senilidade. Para tal, 288 codornas (144 codornas de corte e 144 de postura foram acompanhadas desde a eclosão até os 360 dias de idade. As aves foram distribuídas por idade em 18 grupos, sendo 8 codornas/grupo/tipo de codorna. Após 35 dias as codornas foram mantidas em condições de fotoperíodo de dias longos (17luz: 7escuro. O peso vivo e os valores morfométricos e histológicos testiculares foram determinados em cada período. Os dados obtidos foram analisados para determinar a curva de crescimento e o comportamento dos parâmetros analisados. O modelo que mais se adequou aos dados foi o modelo não linear de Gompertz (Y=A exp [-B e (-kt]. O peso vivo e as características testiculares macro e microscópicas apresentaram comportamento alométrico entre si, sendo que, aproximadamente aos 60 dias os machos apresentaram-se sexualmente desenvolvidos, e estabilizaram o peso corporal por volta dos 100 dias. O testículo direito é mais cranial que o esquerdo e diferem em relação a comprimento e largura, porém não foi observada diferenças (P>0,05 para peso testicular. As codornas de corte apresentaram peso corporal e peso testicular maiores que as codornas de postura, porém as codornas de postura apresentaram peso relativo testicular maior. Durante todo o período analisado os machos puderam ser considerados sexualmente aptos. Os reprodutores apresentaram características sexuais ativas até os 360 dias de idade, representadas pelo tamanho testicular e pela atividade celular nos túbulos seminíferos.

  7. Compact Groups of Galaxies with Complete Spectroscopic Redshifts in the Local Universe

    CERN Document Server

    Sohn, Jubee; Geller, Margaret J; Diaferio, Antonaldo; Rines, Kenneth J; Lee, Myung Gyoon; Lee, Gwang-Ho

    2016-01-01

    Dynamical analysis of compact groups provides important tests of models of compact group formation and evolution. By compiling 2066 redshifts from FLWO/FAST, from the literature, and from SDSS DR12 in the fields of compact groups in \\citet{McC09}, we construct the largest sample of compact groups with complete spectroscopic redshifts in the redshift range $0.01 < z < 0.22$. This large redshift sample shows that the interloper fraction in the \\citet{McC09} compact group candidates is $\\sim 42\\%$. A secure sample of 332 compact groups includes 192 groups with four or more member galaxies and 140 groups with three members. The fraction of early-type galaxies in these compact groups is 62\\%, slightly higher than for the original Hickson compact groups. The velocity dispersions of early- and late-type galaxies in compact groups change little with groupcentric radius; the radii sampled are less than $100 ~h^{-1}$ kpc, smaller than the radii typically sampled by members of massive clusters of galaxies. The phy...

  8. Atacama Compact Array Antennas

    CERN Document Server

    Saito, Masao; Nakanishi, Kouichiro; Naoi, Takahiro; Yamada, Masumi; Saito, Hiro; Ikenoue, Bungo; Kato, Yoshihiro; Morita, Kou-ichiro; Mizuno, Norikazu; Iguchi, Satoru

    2011-01-01

    We report major performance test results of the Atacama Compact Array (ACA) 7-m and 12-m antennas of ALMA (Atacama Large Millimeter/submillimeter Array). The four major performances of the ACA antennas are all-sky pointing (to be not more than 2.0 arcsec), offset pointing (to be < 0.6 arcsec) surface accuracy (< 25(20) micrometer for 12(7)m-antenna), stability of path-length (15 micrometer over 3 min), and high servo capability (6 degrees/s for Azimuth and 3 degrees/s for Elevation). The high performance of the ACA antenna has been extensively evaluated at the Site Erection Facility area at an altitude of about 2900 meters. Test results of pointing performance, surface performance, and fast motion capability are demonstrated.

  9. Compact particle accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Elizondo-Decanini, Juan M.

    2017-08-29

    A compact particle accelerator having an input portion configured to receive power to produce particles for acceleration, where the input portion includes a switch, is provided. In a general embodiment, a vacuum tube receives particles produced from the input portion at a first end, and a plurality of wafer stacks are positioned serially along the vacuum tube. Each of the plurality of wafer stacks include a dielectric and metal-oxide pair, wherein each of the plurality of wafer stacks further accelerate the particles in the vacuum tube. A beam shaper coupled to a second end of the vacuum tube shapes the particles accelerated by the plurality of wafer stacks into a beam and an output portion outputs the beam.

  10. How Robust Are the Size Measurements of High-redshift Compact Galaxies?

    CERN Document Server

    Davari, Roozbeh; Peng, Chien Y; Huang, Song

    2014-01-01

    Massive quiescent galaxies at $z \\approx 2$ are apparently much more compact than galaxies of comparable mass today. How robust are these size measurements? We perform comprehensive simulations to determine possible biases and uncertainties in fitting single-component light distributions to real galaxies. In particular, we examine the robustness of the measurements of the luminosity, size, and other structural parameters. We devise simulations with increasing realism to systematically disentangle effects due to the technique (specifically using GALFIT) and the intrinsic structures of the galaxies. By accurately capturing the detailed substructures of nearby elliptical galaxies and then rescaling their sizes and signal-to-noise to mimic galaxies at different redshifts, we confirm that the massive quiescent galaxies at $z \\approx 2$ are significantly more compact intrinsically than their local counterparts. Their observed compactness is not a result of missing faint outer light due to systematic errors in model...

  11. A Population of Compact Elliptical Galaxies Detected with the Virtual Observatory

    CERN Document Server

    Chilingarian, Igor; Revaz, Yves; Dodonov, Serguei; Durand, Daniel; Durret, Florence; Micol, Alberto; Slezak, Eric

    2009-01-01

    Compact elliptical galaxies are characterized by small sizes and high stellar densities. They are thought to form through tidal stripping of massive progenitors. However, only a handful of them were known, preventing us from understanding the role played by this mechanism in galaxy evolution. We present a population of 21 compact elliptical galaxies gathered with the Virtual Observatory. Follow-up spectroscopy and data mining, using high-resolution images and large databases, show that all the galaxies exhibit old metal-rich stellar populations different from those of dwarf elliptical galaxies of similar masses but similar to those of more massive early-type galaxies, supporting the tidal stripping scenario. Their internal properties are reproduced by numerical simulations, which result in compact dynamically hot remnants resembling the galaxies in our sample.

  12. Spectroscopic Analysis of subluminous B Stars in Binaries with compact Companions

    CERN Document Server

    Geier, S; Edelmann, H; Heber, U; Napiwotzki, R

    2006-01-01

    The masses of compact objects like white dwarfs, neutron stars and black holes are fundamental to astrophysics, but very difficult to measure. We present the results of an analysis of subluminous B (sdB) stars in close binary systems with unseen compact companions to derive their masses and clarify their nature. Radial velocity curves were obtained from time resolved spectroscopy. The atmospheric parameters were determined in a quantitative spectral analysis. Based on high resolution spectra we were able to measure the projected rotational velocity of the stars with high accuracy. The assumption of orbital synchronization makes it possible to constrain inclination angle and companion mass of the binaries. Five invisible companions have masses that are compatible with that of normal white dwarfs or late type main sequence stars. But four sdBs have very massive companions like heavy white dwarfs > 1 Mo, neutron stars or even black holes. Such a high fraction of massive compact companions is not expected from cu...

  13. Galaxy evolution. Isolated compact elliptical galaxies: stellar systems that ran away.

    Science.gov (United States)

    Chilingarian, Igor; Zolotukhin, Ivan

    2015-04-24

    Compact elliptical galaxies form a rare class of stellar system (~30 presently known) characterized by high stellar densities and small sizes and often harboring metal-rich stars. They were thought to form through tidal stripping of massive progenitors, until two isolated objects were discovered where massive galaxies performing the stripping could not be identified. By mining astronomical survey data, we have now found 195 compact elliptical galaxies in all types of environment. They all share similar dynamical and stellar population properties. Dynamical analysis for nonisolated galaxies demonstrates the feasibility of their ejection from host clusters and groups by three-body encounters, which is in agreement with numerical simulations. Hence, isolated compact elliptical and isolated quiescent dwarf galaxies are tidally stripped systems that ran away from their hosts.

  14. MACHO Alert 95-30 First Real-Time Observation of Extended Source Effects in Gravitational Microlensing

    CERN Document Server

    Alcock, C B; Allsman, R A; Alves, D R; Axelrod, T S; Banks, T; Beaulieu, S F; Becker, A C; Becker, R H; Bennett, D P; Bond, I A; Carter, B S; Cook, K H; Dodd, R J; Freeman, K C; Gregg, M D; Griest, K; Hearnshaw, J B; Heller, A; Honda, M; Juga Ku Jun; Kabe, S; Kaspi, S; Kilmartin, P M; Kitamura, A; Kovo, O; Lehner, M J; Love, T E; Maoz, D; Marshall, S L; Matsubara, Y; Minniti, D; Miyamoto, M; Muraki, Y; Nakamura, T; Peterson, B A; Pratt, M R; Quinn, P J; Reid, I N; Reid, M; Reiss, D; Retter, A; Rodgers, A W; Sargent, W L W; Sato, H; Sekiguchi, M; Stetson, P B; Stubbs, C W; Sullivan, D J; Sutherland, W; Tomaney, A B; Vandehei, T; Watase, Y; Welch, D L; Yanagisawa, T; Yoshizawa, M; Yock, P C M

    1997-01-01

    We present analysis of MACHO Alert 95-30, a dramatic gravitational microlensing event towards the Galactic bulge whose peak magnification departs significantly from the standard point-source microlensing model. Alert 95-30 was observed in real-time by the Global Microlensing Alert Network (GMAN), which obtained densely sampled photometric and spectroscopic data throughout the event. We interpret the light-curve ``fine structure'' as indicating transit of the lens across the extended face of the source star. This signifies resolution of a star several kpc distant. We find a lens angular impact parameter theta_{min}/theta_{source} = 0.715 +/- 0.003. This information, along with the radius and distance of the source, provides an additional constraint on the lensing system. Spectroscopic and photometric data indicate the source is an M4 III star of radius 61 +/- 12 Rsun, located on the far side of the bulge at 9 kpc. We derive a lens angular velocity, relative to the source, of 21.5 +/- 4.9 km/s/kpc, where the er...

  15. XMM-Newton observation of MACHO 104.20906.960: a dwarf nova candidate with a 2 h period

    CERN Document Server

    Nucita, A A; De Paolis, F; Ingrosso, G; Maiolo, B M T; Guainazzi, M

    2008-01-01

    The binaries known as cataclysmic variables are particular binary systems in which the primary star (a white dwarf) accretes material from a secondary via Roche-lobe mechanism. Usually, these objects have orbital period of a few hours so that a detailed temporal analysis can be performed. Here, we present Chandra ${\\it XMM}$-Newton observations of a dwarf nova candidate identified in the past by optical observations towards the galactic Bulge and labeled as MACHO 104.20906.960. After a spectral analysis, we used the Lomb-Scargle technique for the period search and evaluated the confidence level using Monte-Carlo simulations. In this case, we found that the $X$-ray source shows a period of $2.03_{-0.07}^{+0.09} $ hours (3$\\sigma$ error) so that it is most likely a system of interacting objects. The modulation of the signal was found with a confidence level of $>$99%. The spectrum can be described by a two thermal plasma components with X-ray flux in the 0.3--10 keV energy band of $1.77_{-0.19}^{+0.16}\\times10^...

  16. O órgão odorífero abdominal do macho de Caligo arisbe Hbn. (Lepidoptera, Brassolidae

    Directory of Open Access Journals (Sweden)

    Rudolf Barth

    1953-12-01

    Full Text Available 1. O órgão odorífero do macho de Caligo arisbe é descrito morfológica e histològicamente. 2. O órgão consta de pares de placas glandulares de hipoderme com escamas odoríferas no quarto e quinto segmento do abdomen e de um aparelho auxiliar na asa posterior para a evaporação da secreção. 3. O aparelho auxiliar consta de 4 filas de cerdas e de uma área nua de evaporação com uma área em forma de anel com cerdas compridas. 4. Devido a falta de trabéculas as escamas odoríferas podem ser aumentadas em forma de vesícula. 5. O exame histológico demonstra nas células glandulares a presença de ergastoplasma e plastósomos grandes no pólo basal da célula. 6. A inserção é especialisada em alto grau. O pedúnculo da escama tem uma situação móvel o que facilita uma emissão da secreção em choque.

  17. Holographically Viable Extensions of Topologically Massive and Minimal Massive Gravity?

    CERN Document Server

    Altas, Emel

    2015-01-01

    Recently, an extension of the topologically massive gravity (TMG) in $2+1$ dimensions, dubbed as minimal massive gravity (MMG), was found which is free of the bulk-boundary unitarity clash that inflicts the former theory and all the other known three dimensional theories. Field equations of MMG differ from those of TMG at quadratic terms in the curvature that do not come from the variation of an action depending on the metric alone. Here we show that MMG is a unique theory and there does not exist a deformation of TMG or MMG at the cubic and quartic order (and beyond) in the curvature that is consistent at the level of the field equations. The only extension of TMG with the desired bulk and boundary properties having a single massive degree of freedom is MMG.

  18. The evolution of massive and very massive stars in clusters

    CERN Document Server

    Vanbeveren, Dany

    2008-01-01

    The present paper reviews massive star (initial mass smaller than 120 M0) and very massive star (initial mass larger than 120 M0) evolution. I will focus on evolutionary facts and questions that may critically affect predictions of population and spectral synthesis of starburst regions. We discuss the ever-lasting factor 2 or more uncertainty in the stellar wind mass loss rates. We may ask ourselves if stellar rotation is one of the keys to understand the universe, why so many massive stars are binary components and why binaries are ignored or are considered as the poor cousins by some people? And finally, do ultra luminous X-ray sources harbor an intermediate mass black hole with a mass of the order of 1000 M0?

  19. Lisina digestível para suínos machos não castrados de alto potencial genético em fase de crescimento

    OpenAIRE

    Kiefer, Charles; Donzele,Juarez Lopes; Oliveira,Rita Flávia Miranda de

    2010-01-01

    Este estudo foi realizado com o objetivo de determinar a exigência de lisina digestível para suínos machos não castrados de alto potencial genético em fase de crescimento. Foram utilizados 320 machos não castrados e 80 castrados, com peso inicial de 27,75±1,61kg, distribuídos em delineamento experimental em blocos ao acaso composto por cinco tratamentos (0,90; 1,00; 1,10 e 1,20% de lisina digestível para não castrados e 1,10% de lisina digestível para castrados), oito repetições, com 1...

  20. The Finslerian compact star model

    Energy Technology Data Exchange (ETDEWEB)

    Rahaman, Farook; Paul, Nupur [Jadavpur University, Department of Mathematics, Kolkata, West Bengal (India); De, S.S. [University of Calcutta, Department of Applied Mathematics, Kolkata (India); Ray, Saibal [Government College of Engineering and Ceramic Technology, Department of Physics, Kolkata, West Bengal (India); Jafry, M.A.K. [Shibpur Dinobundhoo Institution, Department of Physics, Howrah, West Bengal (India)

    2015-11-15

    We construct a toy model for compact stars based on the Finslerian structure of spacetime. By assuming a particular mass function, we find an exact solution of the Finsler-Einstein field equations with an anisotropic matter distribution. The solutions are revealed to be physically interesting and pertinent for the explanation of compact stars. (orig.)

  1. Warm compacting behavior of stainless steel powders

    Institute of Scientific and Technical Information of China (English)

    肖志瑜; 柯美元; 陈维平; 召明; 李元元

    2004-01-01

    The warm compacting behaviors of four different kinds of stainless steel powders, 304L, 316L, 410L and 430L, were studied. The results show that warm compaction can be applied to stainless steel powders. The green densities and strengths of compacts obtained through warm compaction are generally higher than those obtained through cold compaction. The compacting behaviors in warm compaction and cold compaction are similar.Under the compacting pressure of 700 MPa, the warm compacted densities are 0. 10 - 0.22 g/cm3 higher than the cold compacted ones, and the green strengths are 11.5 %-50 % higher. The optimal warm compacting temperature is 100 - 110 ℃. In the die wall lubricated warm compaction, the optimum internal lubricant content is 0.2%.

  2. Variación en loci isoenzimáticos entre machos y hembras de Lutzomyia shannoni (Dyar (Diptera: Psychodidae de Colombia

    Directory of Open Access Journals (Sweden)

    Estrella Cárdenas

    2000-12-01

    Full Text Available Se analizaron por sexo poblaciones silvestres de Lutzomyia shannoni de tres localidades distantes entre si: Palambi (Nariño, Cimitarra (Santander y Chinácota (Norte de Santander, con el fin de establecer la variación en 11 isoenzimas. Estas muestras se compararon con ejemplares de una colonia mantenida en el Laboratorio de Entomologia del INS desde 1992. Se utilizó el sistema de electroforesis vertical en geles de poliacrilarnida al 6%. Se encontró una heterocigosidad promedio entre 18.5 y 24,7% en las hembras silvestres y entre 13,5 y 19.4% entre los machos silvestres. La heterocigosidad promedio en las hembras de la colonia fue de 14,8% mientras que en los machos fue de 20.1%. Se detectaron entre 2,0 y 2,5 alelos por locus. La distancia genética de Nei entre las poblaciones fue baja y osciló entre 0,005 y 0,073. En la muestra de la colonia de 79 individuos. el locus Gpifue homocigoto en todas las hembras y heterocigoto en todos los machos. Aunque esta observación es probablemente una consecuencia de la colonización, indica que el locus Gpi está fuertemente unido a los cromosomas que determinan el sexo, con el alelo Gpi0,62 unido al locus que determina hembras y el alelo Gpi0,72 asociado con el locus que determina machos.

  3. Constraints on the evolutionary mechanisms of massive galaxies since z~1 from their velocity dispersions

    CERN Document Server

    de Arriba, L Peralta; Trujillo, I; Falcón-Barroso, J; Tapia, T; Cardiel, N; Gallego, J; Guzmán, R; Hempel, A; Martín-Navarro, I; Pérez-González, P G; Sánchez-Bláquez, P

    2015-01-01

    Several authors have reported that the dynamical masses of massive compact galaxies (M_star > 10^11 M_sun, r_e ~ 1 kpc), computed as M_dyn = 5.0 sigma_e^2 r_e / G, are lower than their stellar masses M_star. In a previous study from our group, the discrepancy is interpreted as a breakdown of the assumptions of virial equilibrium and homology that underlie the M_dyn determinations. Here we present new spectroscopy of six redshift z~1.0 massive compact ellipticals from the Extended Groth Strip, obtained with the 10.4-m Gran Telescopio Canarias. We obtain velocity dispersions in the range 161 to 340 km s^-1. As found by previous studies of massive compact galaxies, our velocity dispersions are lower than the virial expectation, and all of our galaxies show M_dyn < M_star. Adding data from the literature, we build a sample covering a range of stellar masses and compactness in a narrow redshift range z~1.0. This allows us to exclude systematic effects on the data and evolutionary effects on the galaxy populatio...

  4. Submillimeter galaxies as progenitors of compact quiescent galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Toft, S.; Zirm, A.; Krogager, J.-K.; Man, A. W. S. [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Mariesvej 30, DK-2100 Copenhagen (Denmark); Smolčić, V.; Krpan, J. [Physics Department, University of Zagreb, Bijenička cesta 32, 10002 Zagreb (Croatia); Magnelli, B.; Karim, A. [Argelander Institute for Astronomy, Auf dem Hügel 71, Bonn, D-53121 (Germany); Michalowski, M. [Scottish Universities Physics Alliance, Institute for Astronomy, University of Edinburgh, Royal Observatory, Edinburgh, EH9 3HJ (United Kingdom); Capak, P. [Spitzer Science Center, 314-6 Caltech, 1201 East California Boulevard, Pasadena, CA 91125 (United States); Sheth, K. [National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903 (United States); Schawinski, K. [ETH Zurich, Institute for Astronomy, Department of Physics, Wolfgang-Pauli-Strasse 27, CH-8093 Zurich (Switzerland); Wuyts, S.; Lutz, D.; Staguhn, J.; Berta, S. [MPE, Postfach 1312, D-85741 Garching (Germany); Sanders, D. [Institute for Astronomy, 2680 Woodlawn Drive, University of Hawaii, Honolulu, HI 96822 (United States); Mccracken, H. [Institut dAstrophysique de Paris, UMR7095 CNRS, Universite Pierre et Marie Curie, 98 bis Boulevard Arago, F-75014 Paris (France); Riechers, D., E-mail: sune@dark-cosmology.dk [Department of Astronomy, Cornell University, 220 Space Sciences Building, Ithaca, NY 14853 (United States)

    2014-02-20

    Three billion years after the big bang (at redshift z = 2), half of the most massive galaxies were already old, quiescent systems with little to no residual star formation and extremely compact with stellar mass densities at least an order of magnitude larger than in low-redshift ellipticals, their descendants. Little is known about how they formed, but their evolved, dense stellar populations suggest formation within intense, compact starbursts 1-2 Gyr earlier (at 3 < z < 6). Simulations show that gas-rich major mergers can give rise to such starbursts, which produce dense remnants. Submillimeter-selected galaxies (SMGs) are prime examples of intense, gas-rich starbursts. With a new, representative spectroscopic sample of compact, quiescent galaxies at z = 2 and a statistically well-understood sample of SMGs, we show that z = 3-6 SMGs are consistent with being the progenitors of z = 2 quiescent galaxies, matching their formation redshifts and their distributions of sizes, stellar masses, and internal velocities. Assuming an evolutionary connection, their space densities also match if the mean duty cycle of SMG starbursts is 42{sub −29}{sup +40} Myr (consistent with independent estimates), which indicates that the bulk of stars in these massive galaxies were formed in a major, early surge of star formation. These results suggest a coherent picture of the formation history of the most massive galaxies in the universe, from their initial burst of violent star formation through their appearance as high stellar-density galaxy cores and to their ultimate fate as giant ellipticals.

  5. ATLASGAL --- Complete compact source catalogue: 280\\degr\\ $ <\\ell <$ 60\\degr

    CERN Document Server

    Urquhart, J S; Wyrowski, F; Schuller, F; Bontemps, S; Bronfman, L; Menten, K M; Walmsley, C M; Contreras, Y; Beuther, H; Wienen, M; Linz, H

    2014-01-01

    The APEX Telescope Large Area Survey of the Galaxy (ATLASGAL) is the largest and most sensitive systematic survey of the inner Galactic plane in the submillimetre wavelength regime. The observations were carried out with the Large APEX Bolometer Camera (LABOCA), an array of 295 bolometers observing at 870\\,$\\mu$m (345 GHz). Aim: In this research note we present the compact source catalogue for the 280\\degr\\ $ <\\ell <$ 330\\degr\\ and 21\\degr\\ $ <\\ell <$ 60\\degr\\ regions of this survey. Method: The construction of this catalogue was made with the source extraction routine \\sex\\ using the same input parameters and procedures used to analyse the inner Galaxy region presented in an earlier publication (i.e., 330\\degr\\ $ <\\ell <$ 21\\degr). Results: We have identified 3523 compact sources and present a catalogue of their properties. When combined with the regions already published this provides a comprehensive and unbiased database of ~10163 massive, dense clumps located across the inner Galaxy.

  6. A massive, dead disk galaxy in the early Universe.

    Science.gov (United States)

    Toft, Sune; Zabl, Johannes; Richard, Johan; Gallazzi, Anna; Zibetti, Stefano; Prescott, Moire; Grillo, Claudio; Man, Allison W S; Lee, Nicholas Y; Gómez-Guijarro, Carlos; Stockmann, Mikkel; Magdis, Georgios; Steinhardt, Charles L

    2017-06-21

    At redshift z = 2, when the Universe was just three billion years old, half of the most massive galaxies were extremely compact and had already exhausted their fuel for star formation. It is believed that they were formed in intense nuclear starbursts and that they ultimately grew into the most massive local elliptical galaxies seen today, through mergers with minor companions, but validating this picture requires higher-resolution observations of their centres than is currently possible. Magnification from gravitational lensing offers an opportunity to resolve the inner regions of galaxies. Here we report an analysis of the stellar populations and kinematics of a lensed z = 2.1478 compact galaxy, which-surprisingly-turns out to be a fast-spinning, rotationally supported disk galaxy. Its stars must have formed in a disk, rather than in a merger-driven nuclear starburst. The galaxy was probably fed by streams of cold gas, which were able to penetrate the hot halo gas until they were cut off by shock heating from the dark matter halo. This result confirms previous indirect indications that the first galaxies to cease star formation must have gone through major changes not just in their structure, but also in their kinematics, to evolve into present-day elliptical galaxies.

  7. A new route towards merging massive black holes

    CERN Document Server

    Marchant, Pablo; Podsiadlowski, Philipp; Tauris, Thomas; Moriya, Takashi

    2016-01-01

    Recent advances in gravitational-wave astronomy make the direct detection of gravitational waves from the merger of two stellar-mass compact objects a realistic prospect. Evolutionary scenarios towards mergers of double compact objects generally invoke common-envelope evolution which is poorly understood, leading to large uncertainties in merger rates. We explore the alternative scenario of massive overcontact binary (MOB) evolution, which involves two very massive stars in a very tight binary which remain fully mixed due to their tidally induced high spin. We use the public stellar-evolution code MESA to systematically study this channel by means of detailed simulations. We find that, at low metallicity, MOBs produce double-black-hole (BH+BH) systems that will merge within a Hubble time with mass ratios close to one, in two mass ranges, ~25...60msun and >~ 130msun, with pair instability supernovae (PISNe) being produced in-between. Our models are also able to reproduce counterparts of various stages in the M...

  8. Perturbations in Massive Gravity Cosmology

    CERN Document Server

    Crisostomi, Marco; Pilo, Luigi

    2012-01-01

    We study cosmological perturbations for a ghost free massive gravity theory formulated with a dynamical extra metric that is needed to massive deform GR. In this formulation FRW background solutions fall in two branches. In the dynamics of perturbations around the first branch solutions, no extra degree of freedom with respect to GR ispresent at linearized level, likewise what is found in the Stuckelberg formulation of massive gravity where the extra metric isflat and non dynamical. In the first branch, perturbations are probably strongly coupled. On the contrary, for perturbations around the second branch solutions all expected degrees of freedom propagate. While tensor and vector perturbations of the physical metric that couples with matter follow closely the ones of GR, scalars develop an exponential Jeans-like instability on sub-horizon scales. On the other hand, around a de Sitter background there is no instability. We argue that one could get rid of the instabilities by introducing a mirror dark matter ...

  9. Massive ascites of unknown origin

    Science.gov (United States)

    Yuan, Shi-Min

    2014-01-01

    Massive ascites of unknown origin is an uncommon condition, which represent a diagnostic challenge. Patients with delayed diagnosis and treatment may have a poor prognosis. A 22-year-old female was referred to this hospital due to a 4-year progressive abdominal distension with massive ascites of unknown origin. By thorough investigations, she was eventually diagnosed as chronic calcified constrictive pericarditis. She received pericardiectomy and had an uneventful postoperative course. With a few day paracentesis, ascites did not progress any more. She was doing well at 5-month follow-up and has returned to work. Extracardiac manifestations, such as massive ascites and liver cirrhosis, were rare in patients with constrictive pericarditis. Pericardiectomy can be a radical solution for the treatment of chronic constrictive pericarditis. In order to avoid delayed diagnosis and treatment, physicians have to bear in mind this rare manifestation of chronic calcified constrictive pericarditis. PMID:24600502

  10. Quantum Corrections in Massive Gravity

    CERN Document Server

    de Rham, Claudia; Ribeiro, Raquel H

    2013-01-01

    We compute the one-loop quantum corrections to the potential of ghost-free massive gravity. We show how the mass of external matter fields contribute to the running of the cosmological constant, but do not change the ghost-free structure of the massive gravity potential at one-loop. When considering gravitons running in the loops, we show how the structure of the potential gets destabilized at the quantum level, but in a way which would never involve a ghost with a mass smaller than the Planck scale. This is done by explicitly computing the one-loop effective action and supplementing it with the Vainshtein mechanism. We conclude that to one-loop order the special mass structure of ghost-free massive gravity is technically natural.

  11. Quantum corrections in massive gravity

    Science.gov (United States)

    de Rham, Claudia; Heisenberg, Lavinia; Ribeiro, Raquel H.

    2013-10-01

    We compute the one-loop quantum corrections to the potential of ghost-free massive gravity. We show how the mass of external matter fields contributes to the running of the cosmological constant, but does not change the ghost-free structure of the massive gravity potential at one-loop. When considering gravitons running in the loops, we show how the structure of the potential gets destabilized at the quantum level, but in a way which would never involve a ghost with a mass smaller than the Planck scale. This is done by explicitly computing the one-loop effective action and supplementing it with the Vainshtein mechanism. We conclude that to one-loop order the special mass structure of ghost-free massive gravity is technically natural.

  12. Searching for Compact Radio Sources Associated with UCHII Regions

    Science.gov (United States)

    Masqué, Josep M.; Rodríguez, Luis F.; Trinidad, Miguel A.; Kurtz, Stan; Dzib, Sergio A.; Rodríguez-Rico, Carlos A.; Loinard, Laurent

    2017-02-01

    Ultra-compact (UC)H ii regions represent a very early stage of massive star formation. The structure and evolution of these regions are not yet fully understood. Interferometric observations showed in recent years that compact sources of uncertain nature are associated with some UCH ii regions. To examine this, we carried out VLA 1.3 cm observations in the A configuration of selected UCH ii regions in order to report additional cases of compact sources embedded in UCH ii regions. With these observations, we find 13 compact sources that are associated with 9 UCH ii regions. Although we cannot establish an unambiguous nature for the newly detected sources, we assess some of their observational properties. According to the results, we can distinguish between two types of compact sources. One type corresponds to sources that are probably deeply embedded in the dense ionized gas of the UCH ii region. These sources are photoevaporated by the exciting star of the region and will last for 104–105 years. They may play a crucial role in the evolution of the UCH ii region as the photoevaporated material could replenish the expanding plasma and might provide a solution to the so-called lifetime problem of these regions. The second type of compact sources is not associated with the densest ionized gas of the region. A few of these sources appear resolved and may be photoevaporating objects such as those of the first type, but with significantly lower mass depletion rates. The remaining sources of this second type appear unresolved, and their properties are varied. We speculate on the similarity between the sources of the second type and those of the Orion population of radio sources.

  13. Compact objects from gravitational collapse: an analytical toy model

    Energy Technology Data Exchange (ETDEWEB)

    Malafarina, Daniele [Nazarbayev University, Department of Physics, Astana (Kazakhstan); Joshi, Pankaj S. [Tata Institute of Fundamental Research, Mumbai (India)

    2015-12-15

    We develop here a procedure to obtain regular static configurations resulting from dynamical gravitational collapse of a massive matter cloud in general relativity. Under certain general physical assumptions for the collapsing cloud, we find the class of dynamical models that lead to an equilibrium configuration. To illustrate this, we provide a class of perfect fluid collapse models that lead to a static constant density object as limit. We suggest that similar models might possibly constitute the basis for the description of formation of compact objects in nature. (orig.)

  14. Compact Dexterous Robotic Hand

    Science.gov (United States)

    Lovchik, Christopher Scott (Inventor); Diftler, Myron A. (Inventor)

    2001-01-01

    A compact robotic hand includes a palm housing, a wrist section, and a forearm section. The palm housing supports a plurality of fingers and one or more movable palm members that cooperate with the fingers to grasp and/or release an object. Each flexible finger comprises a plurality of hingedly connected segments, including a proximal segment pivotally connected to the palm housing. The proximal finger segment includes at least one groove defining first and second cam surfaces for engagement with a cable. A plurality of lead screw assemblies each carried by the palm housing are supplied with power from a flexible shaft rotated by an actuator and output linear motion to a cable move a finger. The cable is secured within a respective groove and enables each finger to move between an opened and closed position. A decoupling assembly pivotally connected to a proximal finger segment enables a cable connected thereto to control movement of an intermediate and distal finger segment independent of movement of the proximal finger segment. The dexterous robotic hand closely resembles the function of a human hand yet is light weight and capable of grasping both heavy and light objects with a high degree of precision.

  15. A Massive Substellar Companion to the Massive Giant HD 119445

    CERN Document Server

    Omiya, Masashi; Han, Inwoo; Lee, Byeong-Cheol; Sato, Bun'ei; Kambe, Eiji; Kim, Kang-Min; Yoon, Tae Seog; Yoshida, Michitoshi; Masuda, Seiji; Toyota, Eri; Urakawa, Seitaro; Takada-Hidai, Masahide

    2009-01-01

    We detected a brown dwarf-mass companion around the intermediate-mass giant star HD 119445 (G6III) using the Doppler technique. This discovery is the first result from a Korean-Japanese planet search program based on precise radial velocity measurements. The radial velocity of this star exhibits a periodic Keplerian variation with a period, semi-amplitude and eccentricity of 410.2 days, 413.5 m/s and 0.082, respectively. Adopting a stellar mass of 3.9 M_solar, we were able to confirm the presence of a massive substellar companion with a semimajor axis of 1.71 AU and a minimum mass of 37.6 M_Jup, which falls in the middle of the brown dwarf-mass region. This substellar companion is the most massive ever discovered within 3 AU of a central intermediate-mass star. The host star also ranks among the most massive stars with substellar companions ever detected by the Doppler technique. This result supports the current view of substellar systems that more massive substellar companions tend to exist around more massi...

  16. Broadbeam for Massive MIMO Systems

    Science.gov (United States)

    Qiao, Deli; Qian, Haifeng; Li, Geoffrey Ye

    2016-05-01

    Massive MIMO has been identified as one of the promising disruptive air interface techniques to address the huge capacity requirement demanded by 5G wireless communications. For practical deployment of such systems, the control message need to be broadcast to all users reliably in the cell using broadbeam. A broadbeam is expected to have the same radiated power in all directions to cover users in any place in a cell. In this paper, we will show that there is no perfect broadbeam. Therefore, we develop a method for generating broadbeam that can allow tiny fluctuations in radiated power. Overall, this can serve as an ingredient for practical deployment of the massive MIMO systems.

  17. Cleaning Massive Sonar Point Clouds

    DEFF Research Database (Denmark)

    Arge, Lars Allan; Larsen, Kasper Green; Mølhave, Thomas;

    2010-01-01

    We consider the problem of automatically cleaning massive sonar data point clouds, that is, the problem of automatically removing noisy points that for example appear as a result of scans of (shoals of) fish, multiple reflections, scanner self-reflections, refraction in gas bubbles, and so on. We...... describe a new algorithm that avoids the problems of previous local-neighbourhood based algorithms. Our algorithm is theoretically I/O-efficient, that is, it is capable of efficiently processing massive sonar point clouds that do not fit in internal memory but must reside on disk. The algorithm is also...

  18. Massive Gravitons on Bohmian Congruences

    CERN Document Server

    Fathi, Mohsen

    2016-01-01

    Taking a quantum corrected form of Raychaudhuri equation in a geometric background described by a Lorentz-violating massive theory of gravity, we go through investigating a time-like congruence of massive gravitons affected by a Bohmian quantum potential. We find some definite conditions upon which these gravitons are confined to diverging Bohmian trajectories. The respective behaviour of those quantum potentials are also derived and discussed. Additionally, and through a relativistic quantum treatment of a typical wave function, we demonstrate schematic conditions on the associated frequency to the gravitons, in order to satisfy the necessity of divergence.

  19. High Impact Technology Compact Combustion (HITCC) Compact Core Technologies

    Science.gov (United States)

    2016-01-01

    the CO and CO2 net reaction rates from the FGM. This, in turn, provides another benefit . That is, the source term in YC is not just now dependent on...AFRL-RQ-WP-TR-2016-0010 HIGH IMPACT TECHNOLOGY COMPACT COMBUSTION (HITCC) COMPACT CORE TECHNOLOGIES Andrew W. Caswell Combustion...information exchange, and its publication does not constitute the Government’s approval or disapproval of its ideas or findings. *Disseminated

  20. Spinning Kerr black holes with stationary massive scalar clouds: The large-coupling regime

    CERN Document Server

    Hod, Shahar

    2016-01-01

    We study analytically the Klein-Gordon wave equation for stationary massive scalar fields linearly coupled to spinning Kerr black holes. In particular, using the WKB approximation, we derive a compact formula for the discrete spectrum of scalar field masses which characterize the stationary composed Kerr-black-hole-massive-scalar-field configurations in the large-coupling regime $M\\mu\\gg1$ (here $M$ and $\\mu$ are respectively the mass of the central black hole and the proper mass of the scalar field). We confirm our analytically derived formula for the Kerr-scalar-field mass spectrum with numerical data that recently appeared in the literature.

  1. Compact Grism Spectrometer

    Science.gov (United States)

    Teare, S. W.

    2003-05-01

    Many observatories and instrument builders are retrofitting visible and near-infrared spectrometers into their existing imaging cameras. Camera designs that reimage the focal plane and have the optical filters located in a pseudo collimated beam are ideal candidates for the addition of a spectrometer. One device commonly used as the dispersing element for such spectrometers is a grism. The traditional grism is constructed from a prism that has had a diffraction grating applied on one surface. The objective of such a design is to use the prism wedge angle to select the desired "in-line" or "zero-deviation" wavelength that passes through on axis. The grating on the surface of the prism provides much of the dispersion for the spectrometer. A grism can also be used in a "constant-dispersion" design which provides an almost linear spatial scale across the spectrum. In this paper we provide an overview of the development of a grism spectrometer for use in a near infrared camera and demonstrate that a compact grism spectrometer can be developed on a very modest budget that can be afforded at almost any facility. The grism design was prototyped using visible light and then a final device was constructed which provides partial coverage in the near infrared I, J, H and K astronomical bands using the appropriate band pass filter for order sorting. The near infrared grism presented here provides a spectral resolution of about 650 and velocity resolution of about 450 km/s. The design of this grism relied on a computer code called Xspect, developed by the author, to determine the various critical parameters of the grism. This work was supported by a small equipment grant from NASA and administered by the AAS.

  2. Compact instantaneous water heater

    Energy Technology Data Exchange (ETDEWEB)

    Azevedo, Jorge G.W.; Machado, Antonio R.; Ferraz, Andre D.; Rocha, Ivan C.C. da; Konishi, Ricardo [Companhia de Gas de Santa Catarina (SCGAS), Florianopolis, SC (Brazil); Lehmkuhl, Willian A.; Francisco Jr, Roberto W.; Hatanaka, Ricardo L.; Pereira, Fernando M.; Oliveira, Amir A.M. [Universidade Federal de Santa Catarina (UFSC), Florianopolis, SC (Brazil)

    2012-07-01

    This paper presents an experimental study of combustion in an inert porous medium in a liquid heating device application. This project aims to increase efficiency in the application of natural gas in residential and commercial sectors with the use of advanced combustion and heat transfer. The goal is to facilitate the development of a high performance compact water heater allowing hot water supply for up to two simultaneous showers. The experiment consists in a cylindrical porous burner with an integrated annular water heat exchanger. The reactants were injected radially into the burner and the flame stabilizes within the porous matrix. The water circulates in a coiled pipe positioned at the center of the burner. This configuration allows for heat transfer by conduction and radiation from the solid matrix to the heat exchanger. This article presented preliminary experimental results of a new water heater based on an annular porous burner. The range of equivalence ratios tested varied from 0.65 to 0.8. The power range was varied from 3 to 5 kW. Increasing the equivalence ratio or decreasing the total power input of the burner resulted in increased thermal efficiencies of the water heater. Thermal efficiencies varying from 60 to 92% were obtained. The condition for the goal of a comfortable bath was 20 deg C for 8-12 L/min. This preliminary prototype has achieved water temperature of 11deg C for 5 L/min. Further optimizations will be necessary in order to achieve intense heating with high thermal efficiency. (author)

  3. Massively parallel quantum computer simulator

    NARCIS (Netherlands)

    De Raedt, K.; Michielsen, K.; De Raedt, H.; Trieu, B.; Arnold, G.; Richter, M.; Lippert, Th.; Watanabe, H.; Ito, N.

    2007-01-01

    We describe portable software to simulate universal quantum computers on massive parallel Computers. We illustrate the use of the simulation software by running various quantum algorithms on different computer architectures, such as a IBM BlueGene/L, a IBM Regatta p690+, a Hitachi SR11000/J1, a Cray

  4. Understanding massively open online courses.

    Science.gov (United States)

    Billings, Diane M

    2014-02-01

    Massively open online courses (MOOCs) are an innovative delivery system for educational offerings. MOOCs have been hailed with optimism for making education accessible to many, but at the same time, they have been criticized for poor participant completion rates. Nurse educators are considering whether and how to use MOOCs; this column explains MOOCs and their advantages and disadvantages for nurse educators.

  5. Fast, Massively Parallel Data Processors

    Science.gov (United States)

    Heaton, Robert A.; Blevins, Donald W.; Davis, ED

    1994-01-01

    Proposed fast, massively parallel data processor contains 8x16 array of processing elements with efficient interconnection scheme and options for flexible local control. Processing elements communicate with each other on "X" interconnection grid with external memory via high-capacity input/output bus. This approach to conditional operation nearly doubles speed of various arithmetic operations.

  6. Five-loop massive tadpoles

    CERN Document Server

    Luthe, T

    2016-01-01

    We provide an update on a long-term project that aims at evaluating massive vacuum integrals at the five-loop frontier, with high precision and in various space-time dimensions. A number of applications are sketched, mainly concerning the determination of anomalous dimensions, for quantum field theories in four, three and two dimensions.

  7. Cosmological solutions with massive gravitons

    Energy Technology Data Exchange (ETDEWEB)

    Chamseddine, Ali H. [Physics Department, American University of Beirut (Lebanon); Laboratoire de Mathematiques et Physique Theorique CNRS-UMR 6083, Universite de Tours, Parc de Grandmont, 37200 Tours (France); LE STUDIUM, Loire Valley Institute for Advanced Studies, Tours and Orleans (France); I.H.E.S., F-91440 Bures-sur-Yvette (France); Volkov, Mikhail S., E-mail: volkov@lmpt.univ-tours.fr [Laboratoire de Mathematiques et Physique Theorique CNRS-UMR 6083, Universite de Tours, Parc de Grandmont, 37200 Tours (France)

    2011-10-25

    We present solutions describing spatially closed, open, or flat cosmologies in the massive gravity theory within the recently proposed tetrad formulation. We find that the effect of the graviton mass is equivalent to introducing to the Einstein equations a matter source that can consist of several different matter types - a cosmological term, quintessence, gas of cosmic strings, and non-relativistic cold matter.

  8. Non-local massive gravity

    CERN Document Server

    Modesto, Leonardo

    2013-01-01

    We present a general covariant action for massive gravity merging together a class of "non-polynomial" and super-renormalizable or finite theories of gravity with the non-local theory of gravity recently proposed by Jaccard, Maggiore and Mitsou (arXiv:1305.3034 [hep-th]). Our diffeomorphism invariant action gives rise to the equations of motion appearing in non-local massive massive gravity plus quadratic curvature terms. Not only the massive graviton propagator reduces smoothly to the massless one without a vDVZ discontinuity, but also our finite theory of gravity is unitary at tree level around the Minkowski background. We also show that, as long as the graviton mass $m$ is much smaller the today's Hubble parameter $H_0$, a late-time cosmic acceleration can be realized without a dark energy component due to the growth of a scalar degree of freedom. In the presence of the cosmological constant $\\Lambda$, the dominance of the non-local mass term leads to a kind of "degravitation" for $\\Lambda$ at the late cos...

  9. Supernovae from massive AGB stars

    NARCIS (Netherlands)

    Poelarends, A.J.T.; Izzard, R.G.; Herwig, F.; Langer, N.; Heger, A.

    2006-01-01

    We present new computations of the final fate of massive AGB-stars. These stars form ONeMg cores after a phase of carbon burning and are called Super AGB stars (SAGB). Detailed stellar evolutionary models until the thermally pulsing AGB were computed using three di erent stellar evolution codes. The

  10. Causality Constraints on Massive Gravity

    CERN Document Server

    Camanho, Xian O; Rahman, Rakibur

    2016-01-01

    The parameter space of the de Rham-Gabadadze-Tolley massive gravity ought to be constrained essentially to a line. The theory is shown to admit pp-wave backgrounds on which linear fluctuations otherwise undergo significant time advances, potentially leading to closed time-like curves. This classical phenomenon takes place well within the theory's validity regime.

  11. Supervised detection of anomalous light curves in massive astronomical catalogs

    Energy Technology Data Exchange (ETDEWEB)

    Nun, Isadora; Pichara, Karim [Computer Science Department, Pontificia Universidad Católica de Chile, Santiago (Chile); Protopapas, Pavlos [Institute for Applied Computational Science, Harvard University, Cambridge, MA (United States); Kim, Dae-Won [Max-Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg (Germany)

    2014-09-20

    The development of synoptic sky surveys has led to a massive amount of data for which resources needed for analysis are beyond human capabilities. In order to process this information and to extract all possible knowledge, machine learning techniques become necessary. Here we present a new methodology to automatically discover unknown variable objects in large astronomical catalogs. With the aim of taking full advantage of all information we have about known objects, our method is based on a supervised algorithm. In particular, we train a random forest classifier using known variability classes of objects and obtain votes for each of the objects in the training set. We then model this voting distribution with a Bayesian network and obtain the joint voting distribution among the training objects. Consequently, an unknown object is considered as an outlier insofar it has a low joint probability. By leaving out one of the classes on the training set, we perform a validity test and show that when the random forest classifier attempts to classify unknown light curves (the class left out), it votes with an unusual distribution among the classes. This rare voting is detected by the Bayesian network and expressed as a low joint probability. Our method is suitable for exploring massive data sets given that the training process is performed offline. We tested our algorithm on 20 million light curves from the MACHO catalog and generated a list of anomalous candidates. After analysis, we divided the candidates into two main classes of outliers: artifacts and intrinsic outliers. Artifacts were principally due to air mass variation, seasonal variation, bad calibration, or instrumental errors and were consequently removed from our outlier list and added to the training set. After retraining, we selected about 4000 objects, which we passed to a post-analysis stage by performing a cross-match with all publicly available catalogs. Within these candidates we identified certain known

  12. New Radio Continuum Observations of the Compact Source Projected Inside NGC 6334A

    CERN Document Server

    Rodr'\\iguez, Luis F; Dzib, Sergio A; Loinard, Laurent; Kurtz, Stanley E

    2013-01-01

    A handful of HII regions are known to exhibit a compact radio source near their centers. The nature of these compact radio sources is not well established. We present the analysis of new as well as archival Very Large Array observations of the compact source projected near the center of the NGC 6334A HII region, part of the NGC 6334 complex. We show that the compact source is time variable on a scale of years and determine for one epoch a non-thermal spectrum, suggestive of synchrotron emission. We propose that this source could be the wind interaction region of a massive binary system that could be the ionizing source of NGC 6334A.

  13. Compact, Ultrasensitive Formaldehyde Monitor Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Small Business Innovative Research Phase II proposal seeks to develop a compact UV laser ?based sensor for Earth science and planetary atmosphere exploration....

  14. Countably determined compact abelian groups

    CERN Document Server

    Dikranjan, Dikran

    2008-01-01

    For an abelian topological group G let G^* be the dual group of all continuous characters endowed with the compact open topology. A subgroup D of G determines G if the restriction homomorphism G^* --> D^* of the dual groups is a topological isomorphism. Given a scattered compact subset X of an infinite compact abelian group G such that |X|compact abelian group determined by its countable subgroup must be metrizable. This gives a negative answer to questions of Comfort, Hernandez, Macario, Raczkowski and Trigos-Arrieta, as well as provides short proofs of main results established in three manuscripts by these authors.

  15. Compact energy conversion module Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This STTR project delivers a compact vibration-based Energy Conversion Module (ECM) that powers sensors for purposes like structural health monitoring (SHM). NASA...

  16. What Is Business's Social Compact?

    Science.gov (United States)

    Avishai, Bernard

    1994-01-01

    Under the "new" social compact, businesses must focus on continuous learning and thus have both an obligation to support teaching and an opportunity to profit from it. Learning organizations must also be teaching organizations. (SK)

  17. What Is Business's Social Compact?

    Science.gov (United States)

    Avishai, Bernard

    1994-01-01

    Under the "new" social compact, businesses must focus on continuous learning and thus have both an obligation to support teaching and an opportunity to profit from it. Learning organizations must also be teaching organizations. (SK)

  18. Compact, Airborne Multispecies Sensor Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Small Business Innovative Research Phase I proposal seeks to develop a compact mid-infrared laser spectrometer to benefit Earth science research activities. To...

  19. A dearth of short-period massive binaries in the young massive star forming region M 17. Evidence for a large orbital separation at birth?

    Science.gov (United States)

    Sana, H.; Ramírez-Tannus, M. C.; de Koter, A.; Kaper, L.; Tramper, F.; Bik, A.

    2017-03-01

    Aims: The formation of massive stars remains poorly understood and little is known about their birth multiplicity properties. Here, we aim to quantitatively investigate the strikingly low radial-velocity dispersion measured for a sample of 11 massive pre- and near-main-sequence stars (σ1D= 5.6 ± 0.2 km s-1) in the very young massive star forming region M 17, in order to obtain first constraints on the multiplicity properties of young massive stellar objects. Methods: We compute the radial-velocity dispersion of synthetic populations of massive stars for various multiplicity properties and we compare the obtained σ1D distributions to the observed value. We specifically investigate two scenarios: a low binary fraction and a dearth of short-period binary systems. Results: Simulated populations with low binary fractions () or with truncated period distributions (Pcutoff > 9 months) are able to reproduce the low σ1D observed within their 68%-confidence intervals. Furthermore, parent populations with fbin > 0.42 or Pcutoff star formation process. In the context of the second scenario, compact binaries must form later on, and the cut-off period may be related to physical length-scales representative of the bloated pre-main-sequence stellar radii or of their accretion disks. Conclusions: If the obtained constraints for the M 17's massive-star population are representative of the multiplicity properties of massive young stellar objects, our results may provide support to a massive star formation process in which binaries are initially formed at larger separations, then harden or migrate to produce the typical (untruncated) power-law period distribution observed in few Myr-old OB binaries.

  20. Compact Quiescent Galaxies at Intermediate Redshifts

    CERN Document Server

    Hsu, Li-Yen; Shih, Hsin-Yi

    2014-01-01

    From several searches of the area common to the Sloan Digital Sky Survey and the United Kingdom Infrared Telescope Infrared Deep Sky Survey, we have identified objects that have properties similar to those of the luminous quiescent compact galaxies found at z > 2. Here we present our results of 22 galaxies between z ~ 0.4 and z ~ 0.9 based on observations with the Keck I, Keck II and Subaru telescopes on Mauna Kea. By exploring sizes, morphologies, and stellar populations of these galaxies, we found that most of the galaxies we identified actually formed most of their stars at z 2 in the literature. Several of these young objects appear to be disk-like or possibly prolate. This lines up with several previous studies, which found that massive quiescent galaxies at high redshifts often have disk-like morphologies. If these galaxies were to be confirmed to be disks, their formation would be more likely caused by gas accretion than by major mergers. On the other hand, if these galaxies were to be confirmed to be...

  1. Chemical Evolution of Blue Compact Galaxies

    Institute of Scientific and Technical Information of China (English)

    Fei Shi; Xu Kong; Fu-Zhen Cheng

    2006-01-01

    Based on a sample of 72 Blue Compact Galaxies (BCGs) observed with the 2.16 m telescope of the National Astronomical Observatories, Chinese Academy of Sciences (NAOC) and about 4000 strong emission line galaxies from the Sloan Digital Sky Survey,we analyzed their chemical evolution history using the revised chemical evolution model of Larsen et al. Our sample covers a much larger metallicity range (7.2<12+log(O/H) <9.0). We found that, in order to reproduce the observed abundance pattern and gas fraction over the whole metallicity range, a relatively continuous star formation history is needed for high metallicity galaxies, while assuming a series of instantaneous bursts with long quiescent periods (some Gyrs) for low metallicity galaxies. Model calculations also show that only the closed-box model is capable of reproducing the observational data over the whole metallicity range. Models that consider the ordinary winds and/or inflow can only fit the observations in the low metallicity range, and a model with enriched wind cannot fit the data in the whole metallicity range. This implies that the current adopted simple wind and inflow models are not applicable to massive galaxies, where the underlying physics of galactic winds or inflow could be more complicated.

  2. Ionized Outflows from Compact Steep Spectrum Sources

    CERN Document Server

    Shih, Hsin-Yi; Kewley, Lisa

    2013-01-01

    Massive outflows are known to exist, in the form of extended emission-line regions (EELRs), around about one-third of powerful FR II radio sources. We investigate the origin of these EELRs by studying the emission-line regions around compact-steep-spectrum (CSS) radio galaxies that are younger (10$^3$ to 10$^5$ years old) versions of the FR II radio galaxies. We have searched for and analyzed the emission-line regions around 11 CSS sources by taking integral field spectra using GMOS on Gemini North. We fit the [\\ion{O}{3}] $\\lambda 5007$ line and present the velocity maps for each detected emission-line region. We find, in most cases, that the emission-line regions have multi-component velocity structures with different velocity dispersions and/or flux distributions for each component. The velocity gradients of the emission-line gas are mostly well aligned with the radio axis, suggesting a direct causal link between the outflowing gas and the radio jets. The complex velocity structure may be a result of diffe...

  3. Molecular clouds associated with compact HII regionsin Galactic plane

    Institute of Scientific and Technical Information of China (English)

    孙锦; 沈家健; 孙艳春; 张燕平

    2002-01-01

    13CO (J = 1 - 0) emission of massive star forming region including 15 ultracompact and 4compact HII regions in Galactic plane was mapped with the 13.7 m millimeter wave telescope of Purple Mountain Observatory. The present observations provide the first complete structure of the clouds in 13CO with a higher spatial resolution and a wide-field coverage of 28′×45′. Combined with the images of far-infrared emission and dust color temperature obtained from ISSA, various possible dynamical connections between the compact HII regions and associated clouds were found. We presente some reasons to explain the formation of new dense cold core and molecular emission cavity in the massive star formation and early evolution. The luminosities of excitation stars for all HII regions and the main parameters of associated clouds are also derived. The results show that the newborn stars' luminosities are correlated with the 13CO column densities, masses (in 55"beam) and 13CO velocity widths obviously.``

  4. Directional Oscillations, Concentrations, and Compensated Compactness via Microlocal Compactness Forms

    Science.gov (United States)

    Rindler, Filip

    2015-01-01

    This work introduces microlocal compactness forms (MCFs) as a new tool to study oscillations and concentrations in L p -bounded sequences of functions. Decisively, MCFs retain information about the location, value distribution, and direction of oscillations and concentrations, thus extending at the same time the theories of (generalized) Young measures and H-measures. In L p -spaces oscillations and concentrations precisely discriminate between weak and strong compactness, and thus MCFs allow one to quantify the difference in compactness. The definition of MCFs involves a Fourier variable, whereby differential constraints on the functions in the sequence can also be investigated easily—a distinct advantage over Young measure theory. Furthermore, pointwise restrictions are reflected in the MCF as well, paving the way for applications to Tartar's framework of compensated compactness; consequently, we establish a new weak-to-strong compactness theorem in a "geometric" way. After developing several aspects of the abstract theory, we consider three applications; for lamination microstructures, the hierarchy of oscillations is reflected in the MCF. The directional information retained in an MCF is harnessed in the relaxation theory for anisotropic integral functionals. Finally, we indicate how the theory pertains to the study of propagation of singularities in certain systems of PDEs. The proofs combine measure theory, Young measures, and harmonic analysis.

  5. Multimedia over massive MIMO wireless systems

    OpenAIRE

    Wang, Haichao; Ge, Xiaohu; Zi, Ran; Zhang, Jing; Ni, Qiang

    2015-01-01

    To satisfy the massive wireless traffic transmission generated by multimedia applications, the massive multi-input-multi-output (MIMO) wireless system has emerged as a possible solution for future 5G wireless communication systems. However, the mutual coupling effect of massive MIMO systems has a negative effect potential on the wireless capacity. In this paper, the receive diversity gain is first defined and analyzed for massive MIMO wireless systems. Furthermore, we propose an effective cap...

  6. Características reprodutivas de onças-pintadas (Panthera onca machos, mantidos em cativeiro

    Directory of Open Access Journals (Sweden)

    Ronaldo Gonçalves Morato

    1999-01-01

    Full Text Available Quatro onças pintadas (Panthera onca, machos, adultos, mantidos no Zoológico de São Paulo (SP-Brasil, foram submetidos a avaliação seminal, quantificação hormonal e biometria testicular a cada dois meses pelo período de um ano. As amostras de sêmen foram obtidas por eletroejaculação e analisadas quanto ao pH, volume total, motilidade (0-100%, vigor (0-5, espermatozóides totais e morfologia. Amostras de sangue foram obtidas pela punção da veia cefálica imediatamente antes da eletroejaculação e o plasma foi estocado a -20ºC até a realização do radioimunoensaio para quantificação de testosterona. Comprimento e largura dos testículos direito e esquerdo foram obtidos com auxílio de paquímetro e os valores obtidos foram combinados para a obtenção de volume testicular. As amostras de sêmen mostraram elevado índice de espermatozóides morfologicamente anormais (média = 51%, baixos índice de motilidade (50,6% e vigor (2,2. Não foi encontrada correlação entre as características seminais, níveis plasmáticos de testosterona e volume testicular (Teste de Correlação de Spearman. Não foi detectado efeito da estação durante o ano para qualidade espermática, testosterona sérica e volume testicular (p>;0,05, Teste de Friedman. Os resultados sugerem que as onças pintadas mantidas em cativeiro não são sazonais e que a colheita e avaliação espermática podem ser realizadas em qualquer período do ano sem que haja perda na qualidade espermática. No entanto, as causas de elevado índice de espermatozóides morfologicamente anormais, encontrados neste estudo, devem ser investigadas.

  7. Vacuum polarization of massive spinor fields in static black-string backgrounds

    CERN Document Server

    Piedra, Owen Pavel Fernandez

    2007-01-01

    The renormalized mean value of the quantum Lagrangian and the corresponding components of the Energy-Momentum tensor for massive spinor fields coupled to an arbitrary gravitational field configuration having cylindrical symmetry are analytically evaluated using the Schwinger-DeWitt approximation, up to second order in the inverse mass value. The general results are employed to explicitly derive compact analytical expressions for the quantum mean Lagrangian and Energy- Momentum tensor in the particular background of the Black-String space-time.

  8. Stationary bound-state scalar configurations supported by rapidly-spinning exotic compact objects

    Science.gov (United States)

    Hod, Shahar

    2017-07-01

    Some quantum-gravity theories suggest that the absorbing horizon of a classical black hole should be replaced by a reflective surface which is located a microscopic distance above the would-be classical horizon. Instead of an absorbing black hole, the resulting horizonless spacetime describes a reflective exotic compact object. Motivated by this intriguing prediction, in the present paper we explore the physical properties of exotic compact objects which are linearly coupled to stationary bound-state massive scalar field configurations. In particular, solving the Klein-Gordon wave equation for a stationary scalar field of proper mass μ and spheroidal harmonic indices (l , m) in the background of a rapidly-rotating exotic compact object of mass M and angular momentum J = Ma, we derive a compact analytical formula for the discrete radii {rc (μ , l , m , M , a ; n) } of the exotic compact objects which can support the stationary bound-state massive scalar field configurations. We confirm our analytical results by direct numerical computations.

  9. Massive binary stars as a probe of massive star formation

    Science.gov (United States)

    Kiminki, Daniel C.

    2010-10-01

    Massive stars are among the largest and most influential objects we know of on a sub-galactic scale. Binary systems, composed of at least one of these stars, may be responsible for several types of phenomena, including type Ib/c supernovae, short and long gamma ray bursts, high-velocity runaway O and B-type stars, and the density of the parent star clusters. Our understanding of these stars has met with limited success, especially in the area of their formation. Current formation theories rely on the accumulated statistics of massive binary systems that are limited because of their sample size or the inhomogeneous environments from which the statistics are collected. The purpose of this work is to provide a higher-level analysis of close massive binary characteristics using the radial velocity information of 113 massive stars (B3 and earlier) and binary orbital properties for the 19 known close massive binaries in the Cygnus OB2 Association. This work provides an analysis using the largest amount of massive star and binary information ever compiled for an O-star rich cluster like Cygnus OB2, and compliments other O-star binary studies such as NGC 6231, NGC 2244, and NGC 6611. I first report the discovery of 73 new O or B-type stars and 13 new massive binaries by this survey. This work involved the use of 75 successful nights of spectroscopic observation at the Wyoming Infrared Observatory in addition to observations obtained using the Hydra multi-object spectrograph at WIYN, the HIRES echelle spectrograph at KECK, and the Hamilton spectrograph at LICK. I use these data to estimate the spectrophotometric distance to the cluster and to measure the mean systemic velocity and the one-sided velocity dispersion of the cluster. Finally, I compare these data to a series of Monte Carlo models, the results of which indicate that the binary fraction of the cluster is 57 +/- 5% and that the indices for the power law distributions, describing the log of the periods, mass

  10. Compactness in intuitionistic fuzzy topological spaces

    Directory of Open Access Journals (Sweden)

    S. E. Abbas

    2005-02-01

    Full Text Available We introduce fuzzy almost continuous mapping, fuzzy weakly continuous mapping, fuzzy compactness, fuzzy almost compactness, and fuzzy near compactness in intuitionistic fuzzy topological space in view of the definition of Å ostak, and study some of their properties. Also, we investigate the behavior of fuzzy compactness under several types of fuzzy continuous mappings.

  11. Minimal theory of massive gravity

    CERN Document Server

    De Felice, Antonio

    2016-01-01

    We propose a new theory of massive gravity with only two propagating degrees of freedom. After defining the theory in the unitary gauge in the vielbein language, we shall perform a Hamiltonian analysis to count the number of physical degrees of freedom, and then study some phenomenologies. While the homogeneous and isotropic background cosmology and the tensor linear perturbations around it are described by exactly the same equations as those in the de Rham - Gabadadze - Tolley (dRGT) massive gravity, the scalar and vector gravitational degrees of freedom are absent in the new theory at the fully nonlinear level. Hence the new theory provides a stable nonlinear completion of the self-accelerating cosmological solution that was originally found in the dRGT theory.

  12. Compact Intracloud Discharges

    Energy Technology Data Exchange (ETDEWEB)

    Smith, David A. [Univ. of Colorado, Boulder, CO (United States)

    1998-11-01

    In November of 1993, mysterious signals recorded by a satellite-borne broadband VHF radio science experiment called Blackboard led to a completely unexpected discovery. Prior to launch of the ALEXIS satellite, it was thought that its secondary payload, Blackboard, would most often detect the radio emissions from lightning when its receiver was not overwhelmed by noise from narrowband communication carriers. Instead, the vast majority of events that triggered the instrument were isolated pairs of pulses that were one hundred times more energetic than normal thunderstorm electrical emissions. The events, which came to be known as TIPPs (for transionospheric pulse pairs), presented a true mystery to the geophysics community. At the time, it was not even known whether the events had natural or anthropogenic origins. After two and one half years of research into the unique signals, two ground-based receiver arrays in New Mexico first began to detect and record thunderstorm radio emissions that were consistent with the Blackboard observations. On two occasions, the ground-based systems and Blackboard even recorded emissions that were produced by the same exact events. From the ground based observations, it has been determined that TIPP events areproduced by brief, singular, isolated, intracloud electrical discharges that occur in intense regions of thunderstorms. These discharges have been dubbed CIDS, an acronym for compact intracloud discharges. During the summer of 1996, ground-based receiver arrays were used to record the electric field change signals and broadband HF emissions from hundreds of CIDS. Event timing that was accurate to within a few microseconds made possible the determination of source locations using methods of differential time of arrival. Ionospheric reflections of signals were recorded in addition to groundwave/line-of-sight signals and were used to determine accurate altitudes for the discharges. Twenty-four CIDS were recorded from three

  13. Formation of Massive Stars: Theoretical Considerations

    Science.gov (United States)

    Yorke, Harold W.

    2008-01-01

    This slide presentation reviews theoretical considerations of the formation of massive stars. It addresses the questions that assuming a gravitationally unstable massive clump, how does enough material become concentrated into a sufficiently small volume within a sufficiently short time? and how does the forming massive star influence its immediate surroundings to limit its mass?

  14. Theoretical Considerations of Massive Star Formation

    Science.gov (United States)

    Yorke, Harold W.

    2006-01-01

    This viewgraph presentation reviews the formation of massive stars. The formation of massive stars is different in many ways from the formation of other stars. The presentation shows the math, and the mechanisms that must be possible for a massive star to form.

  15. Massive gravity on a brane

    Energy Technology Data Exchange (ETDEWEB)

    Chacko, Z.; Graesser, M.L.; Grojean, C.; Pilo, L.

    2003-12-11

    At present no theory of a massive graviton is known that is consistent with experiments at both long and short distances. The problem is that consistency with long distance experiments requires the graviton mass to be very small. Such a small graviton mass however implies an ultraviolet cutoff for the theory at length scales far larger than the millimeter scale at which gravity has already been measured. In this paper we attempt to construct a model which avoids this problem. We consider a brane world setup in warped AdS spacetime and we investigate the consequences of writing a mass term for the graviton on a the infrared brane where the local cutoff is of order a large (galactic) distance scale. The advantage of this setup is that the low cutoff for physics on the infrared brane does not significantly affect the predictivity of the theory for observers localized on the ultraviolet brane. For such observers the predictions of this theory agree with general relativity at distances smaller than the infrared scale but go over to those of a theory of massive gravity at longer distances. A careful analysis of the graviton two-point function, however, reveals the presence of a ghost in the low energy spectrum. A mode decomposition of the higher dimensional theory reveals that the ghost corresponds to the radion field. We also investigate the theory with a brane localized mass for the graviton on the ultraviolet brane, and show that the physics of this case is similar to that of a conventional four dimensional theory with a massive graviton, but with one important difference: when the infrared brane decouples and the would-be massive graviton gets heavier than the regular Kaluza-Klein modes, it becomes unstable and it has a finite width to decay off the brane into the continuum of Kaluza-Klein states.

  16. Massive star clusters in galaxies

    CERN Document Server

    Harris, William E

    2009-01-01

    The ensemble of all star clusters in a galaxy constitutes its star cluster system. In this review, the focus of the discussion is on the ability of star clusters, particularly the systems of old massive globular clusters (GCSs), to mark the early evolutionary history of galaxies. I review current themes and key findings in GCS research, and highlight some of the outstanding questions that are emerging from recent work.

  17. The Massive Thermal Basketball Diagram

    CERN Document Server

    Andersen, J O; Strickland, Michael T; Andersen, Jens O.; Braaten, Eric; Strickland, Michael

    2000-01-01

    The "basketball diagram" is a three-loop vacuum diagram for a scalar fieldtheory that cannot be expressed in terms of one-loop diagrams. We calculatethis diagram for a massive scalar field at nonzero temperature, reducing it toexpressions involving three-dimensional integrals that can be easily evaluatednumerically. We use this result to calculate the free energy for a massivescalar field with a phi^4 interaction to three-loop order.

  18. The Nature of Massive Neutrinos

    Directory of Open Access Journals (Sweden)

    S. T. Petcov

    2013-01-01

    massive Majorana neutrinos are summarised. The physics potential of the experiments, searching for ( β β 0 ν -decay for providing information on the type of the neutrino mass spectrum, on the absolute scale of neutrino masses, and on the Majorana CP-violation phases in the PMNS neutrino mixing matrix, is also briefly discussed. The opened questions and the main goals of future research in the field of neutrino physics are outlined.

  19. The Construction of Finer Compact Topologies

    OpenAIRE

    2005-01-01

    It is well known that each locally compact strongly sober topology is contained in a compact Hausdorff topology; just take the supremum of its topology with its dual topology. On the other hand, examples of compact topologies are known that do not have a finer compact Hausdorff topology. This led to the question (first explicitly formulated by D.E. Cameron) whether each compact topology is contained in a compact topology with respect to which all compact sets are closed. (For the obvious r...

  20. Compactly convex sets in linear topological spaces

    CERN Document Server

    Banakh, T; Ravsky, O

    2012-01-01

    A convex subset X of a linear topological space is called compactly convex if there is a continuous compact-valued map $\\Phi:X\\to exp(X)$ such that $[x,y]\\subset\\Phi(x)\\cup \\Phi(y)$ for all $x,y\\in X$. We prove that each convex subset of the plane is compactly convex. On the other hand, the space $R^3$ contains a convex set that is not compactly convex. Each compactly convex subset $X$ of a linear topological space $L$ has locally compact closure $\\bar X$ which is metrizable if and only if each compact subset of $X$ is metrizable.

  1. Estacionalidad reproductiva de los machos cabríos de la raza Alpino-Francés adaptados al subtrópico Mexicano

    Directory of Open Access Journals (Sweden)

    Evaristo Carrillo

    2010-01-01

    Full Text Available El objetivo del presente estudio fue determinar un posible patrón de estacionalidad reproductiva de los machos cabríos de la raza Alpino-Francés adaptados a condiciones intensivas del subtrópico Mexicano (26° LN. El estudio consideró 11 machos, los cuales fueron sometidos a las variaciones naturales del fotoperiodo de la Comarca Lagunera (13,41 h/luz durante el solsticio de verano y 10,19 h/luz en el solsticio de invierno. Los animales tuvieron libre acceso a heno de alfalfa (17 % PC y 200 g de concentrado comercial (14 % PC animal-1 día.1, durante todo el período experimental (diciembre a septiembre. Se observó una disminución (P<0.05 en la motilidad progresiva y el porcentaje de espermatozoides vivos al pasar de 1.4 ± 0.1 (escala de 1-5 y 21 ± 2 % de enero a junio, a valores de 2.5 ± 0.2 y del 49 ± 4 % durante julio a diciembre, respectivamente. La latencia a eyacular en vagina artificial fue de 102 ± 7 seg de diciembre a julio, observando una reducción a 52 ± 1 seg entre agosto y septiembre. El volumen del eyaculado fue de 0.1 ± 0.03 ml eyaculado-1 de enero a julio, observando un incremento a 0.5 ± 0.04 ml eyaculado-1 durante agosto, septiembre y diciembre. Los resultados del estudio demuestran que machos cabríos Alpino-Francés jóvenes criados con un esquema intensivo a 26° LN en el subtrópico mexicano muestran un patrón estacional con respecto a calidad espermática, libido y peso testicular que se extiende de enero a julio en esta latitud.

  2. Eficiência da eletroejaculação de morfotipos machos do camarão-de-água-doce Macrobrachium rosenbergii

    Directory of Open Access Journals (Sweden)

    Goldberg Rubens Sterental

    2000-01-01

    Full Text Available RESUMO - O objetivo deste trabalho foi avaliar a aplicabilidade da técnica de eletroejaculação para manejos de inseminação artificial, bem como o potencial ejaculatório de cada um dos tipos morfológicos de machos adultos do Macrobrachium rosenbergii. Estímulos elétricos foram aplicados em 48 exemplares de camarão-de-água-doce, recém capturados em viveiros de engorda, para melhor compreensão do comportamento reprodutivo de cada um: os de quela azul (BC, sexualmente ativos e dominantes; os de quela laranja (OC, sexualmente inativos; e os pequenos (SM, com comportamento oportunista, os quais somente realizam a cópula, caso a corte da fêmea tenha sido previamente realizada por um macho BC. Não houve diferença entre as freqüências de ejaculação observadas para machos OC e BC, que foram 85 e 100%, respectivamente, demonstrando que os primeiros possuem potencial fisiológico para a cópula. A freqüência de 46,2%, nos testes de eletroejaculação bem sucedidos para os indivíduos SM, foi mais baixa em relação aos outros dois morfotipos. A freqüência de 79,2% de ejaculações, obtida entre o total de animais usados, demonstrou o potencial dessa técnica para a obtenção de espermatóforos em quantidade suficiente para a manutenção de fêmeas ovadas em épocas de baixas temperaturas.

  3. Response compaction for system-on-a-chip based on advanced convolutional codes

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    This paper addresses the problem of test response compaction. In order to maximize compaction ratio, a single-output compactor based on a (n, n-1, m, 3) convolutional code is presented. When the proposed theorems are satisfied, the compactor can avoid two and any odd erroneous bits cancellations, and handle one unknown bit (X bit). When the X bits in response are clustered, multiple-weight check matrix design algorithm can be used to reduce the effect of massive X bits. Some extended experimental results show that the proposed encoder has an acceptable-level X tolerant capacity and low error cancellations probability.

  4. Two new confirmed massive relic galaxies: red nuggets in the present-day Universe

    Science.gov (United States)

    Ferré-Mateu, Anna; Trujillo, Ignacio; Martín-Navarro, Ignacio; Vazdekis, Alexandre; Mezcua, Mar; Balcells, Marc; Domínguez, Lilian

    2017-01-01

    We confirm two new local massive relic galaxies, i.e. untouched survivors of the early universe massive population: Mrk 1216 and PGC 032873. Both show early and peaked formation events within very short timescales (formation histories remain virtually unchanged out to several effective radii, even when considering the steeper IMF values inferred out to ˜3 effective radii. Their morphologies, kinematics and density profiles are like those found in the z>2 massive population, setting them apart of the typical z˜0 massive early-type galaxies. We find that there seems to exist a degree of relic that is related on how far into the path to become one of these typical z˜0 massive galaxies the compact relic has undergone. This path is partly dictated by the environment the galaxy lives in. For galaxies in rich environments, such as the previously reported relic galaxy NGC 1277, the most extreme properties (e.g. sizes, short formation timescales, larger super-massive black holes) are expected, while lower density environments will have galaxies with delayed and/or extended star formations, slightly larger sizes and not that extreme black hole masses. The confirmation of 3 relic galaxies up to a distance of 106 Mpc implies a lower limit in the number density of these red nuggets in the local universe of 6× 10-7 Mpc3, which is within the theoretical expectations.

  5. MASSIVE INFANT STARS ROCK THEIR CRADLE

    Science.gov (United States)

    2002-01-01

    Extremely intense radiation from newly born, ultra-bright stars has blown a glowing spherical bubble in the nebula N83B, also known as NGC 1748. A new NASA Hubble Space Telescope image has helped to decipher the complex interplay of gas and radiation of a star-forming region in a nearby galaxy. The image graphically illustrates just how these massive stars sculpt their environment by generating powerful winds that alter the shape of the parent gaseous nebula. These processes are also seen in our Milky Way in regions like the Orion Nebula. The Hubble telescope is famous for its contribution to our knowledge about star formation in very distant galaxies. Although most of the stars in the Universe were born several billions of years ago, when the Universe was young, star formation still continues today. This new Hubble image shows a very compact star-forming region in a small part of one of our neighboring galaxies - the Large Magellanic Cloud. This galaxy lies only 165,000 light-years from our Milky Way and can easily be seen with the naked eye from the Southern Hemisphere. Young, massive, ultra-bright stars are seen here just as they are born and emerge from the shelter of their pre-natal molecular cloud. Catching these hefty stars at their birthplace is not as easy as it may seem. Their high mass means that the young stars evolve very rapidly and are hard to find at this critical stage. Furthermore, they spend a good fraction of their youth hidden from view, shrouded by large quantities of dust in a molecular cloud. The only chance is to observe them just as they start to emerge from their cocoon - and then only with very high-resolution telescopes. Astronomers from France, the U.S., and Germany have used Hubble to study the fascinating interplay between gas, dust, and radiation from the newly born stars in this nebula. Its peculiar and turbulent structure has been revealed for the first time. This high-resolution study has also uncovered several individual stars

  6. Compact magnetic confinement fusion: Spherical torus and compact torus

    Directory of Open Access Journals (Sweden)

    Zhe Gao

    2016-05-01

    Full Text Available The spherical torus (ST and compact torus (CT are two kinds of alternative magnetic confinement fusion concepts with compact geometry. The ST is actually a sub-category of tokamak with a low aspect ratio; while the CT is a toroidal magnetic configuration with a simply-connected geometry including spheromak and field reversed pinch. The ST and CT have potential advantages for ultimate fusion reactor; while at present they can also provide unique fusion science and technology contributions for mainstream fusion research. However, some critical scientific and technology issues should be extensively investigated.

  7. Diseño de un sistema de tamizado semicontinuo para el aislamiento de almidón de plátano macho (musa paradisiaca l.)

    OpenAIRE

    Ramírez Cortes, Roberto

    2016-01-01

    El plátano macho (Musa paradisiaca L.) es un fruto climatérico que se recolecta en un estado de madurez fisiológica. En esta etapa posee un alto contenido de almidón, por lo cual es una importante fuente alterna para el aislamiento del polisacárido. Hasta ahora, los procesos reportados para su aislamiento, son llevados a cabo en lotes, y durante la operación de tamizado, se emplean grandes cantidades de agua para producir la liberación de los gránulos de almidón. El objetivo de este trabajo f...

  8. Control de la reproducción de los caprinos del subtrópico mexicano utilizando tratamientos fotoperiódicos y efecto macho

    OpenAIRE

    José Alberto Delgadillo Sánchez; José Alfredo Flores Cabrera; Francisco Gerardo Véliz Deras; Gerardo Duarte Moreno; Jesús Vielma Sifuentes; Pascal Poindron Massot; Benoît Malpaux

    2003-01-01

    En los caprinos locales del norte de México, en particular los de la Comarca Lagunera (26°N), existe una estacionalidad reproductiva. En los machos el periodo de reposo sexual ocurre de enero a abril, mientras que en las hembras, el periodo de anestro sucede de marzo a agosto. En ambos sexos, esta estacionalidad es provocada por las variaciones de la duración del día. Los días cortos estimulan la actividad sexual y los días largos la inhiben. Asimismo, la exposición a 2.5 meses de días largos...

  9. Producción masiva y simultánea de machos de Ceratitis capitata (Diptera: Tephritidae y parasitoides Dichasmimorpha longicaudata (Hymenoptera: Braconidae

    Directory of Open Access Journals (Sweden)

    Silvia N. LÓPEZ

    2006-01-01

    Full Text Available En la línea de sexado genético «Cast191» las hembras de Ceratitis capitata son homocigotas para el gen slow , lo que reduce su velocidad de desarrollo; los machos son heterocigotas y muestran una velocidad de desarrollo normal. Esta característica permitió producir, con Cast191, machos estériles por un lado, y parasitoides criados sobre las larvas remanentes por el otro. Nuestro objetivo con este trabajo fue producir ambos insumos simultáneamente y a una escala mayor que hasta ahora. Además, bajo estas condiciones, y en un intento por aumentar la separación entre sexos, se aplicó a las larvas del primer estadío un pulso de 15º C, durante 1 ó 2 días, luego del cual se las mantuvo a 20º C ó 25º C, hasta que entraron al estado de pupa, luego se mantuvo todo el material a 25º C. La mejor separación de sexos, lograda con el tratamiento a 20º C sin pulso de frío, se usó para comparar la calidad del parasitoide Diachasmimorpha longicaudata, criado sobre las larvas obtenidas tras la separación de los machos, con aquellos criados sobre la línea salvaje. Para ello, este tratamiento de separación fue aplicado en la cría de la mosca, y el material remanente de dieta con larvas fue expuesto al parasitoide. La tasa de parasitismo obtenida fue semejante a la hallada sobre la línea salvaje, y la tasa sexual de la F1 del parasitoide presentó un sesgo hacia las hembras aún mayor. Se discute la factibilidad de utilizar la línea Cast191 de C. Capitata, para la producción a mayor escala de machos de mosca y para la cría masiva del parasitoide D. longicaudata.

  10. Uso de testosterona en hembras caprinas adultas para la inducción de comportamiento de macho para la detección de estros

    OpenAIRE

    Rubén Darío Martínez Rojero; Lorenzo Reyna Santamaría

    2016-01-01

    Con el objetivo de evaluar dos tratamientos hormonales basados en testosterona sintética, para inducir comportamiento de macho en cabras de desecho, un grupo recibió 100 mg de propionato de testosterona, más 500 mg de enantato de testosterona con diferencia de 14 d; mientras que el otro grupo recibió dos inyecciones con 500 mg de enantato de testosterona. El tratamiento propionato+enantato superó en la eficiencia para la detección de estros (84.40%) a los ma- chos con mandil (test...

  11. EFECTO DE LA BEBIDA GASIFICADA EN LA PARED GÁSTRICA DE RATAS MACHO CON GASTRITIS INDUCIDA POR ÁCIDO ACETILSALICÍLICO

    OpenAIRE

    Alejandro Martinez; Katia Bravo; Saúl Gonzales; Diana Lecca; Melissa Mendoza; Melissa Paragua; Isabel Pinedo; Luis Ramos; Miriam Salcedo; Diana Torpoco; Yao-Te Wang; Ernesto Ráez

    2011-01-01

    Objetivo: Evaluar el efecto del consumo prolongado de una bebida gasificada sobre la pared gástrica de ratas con gastritis inducida por ácido acetilsalicílico. Métodos: Estudio experimental Participantes: ratas macho de 3,5 meses de edad Intervenciones: Se indujo gastritis mediante la administración oral diaria de 300 mg/kg de ácido acetilsalicílico, en solución con agua (grupo control) o bebida gasificada (grupo experimental). Luego de tres semanas se evaluaron las alteraciones histopatoló...

  12. Viral RNAs are unusually compact.

    Directory of Open Access Journals (Sweden)

    Ajaykumar Gopal

    Full Text Available A majority of viruses are composed of long single-stranded genomic RNA molecules encapsulated by protein shells with diameters of just a few tens of nanometers. We examine the extent to which these viral RNAs have evolved to be physically compact molecules to facilitate encapsulation. Measurements of equal-length viral, non-viral, coding and non-coding RNAs show viral RNAs to have among the smallest sizes in solution, i.e., the highest gel-electrophoretic mobilities and the smallest hydrodynamic radii. Using graph-theoretical analyses we demonstrate that their sizes correlate with the compactness of branching patterns in predicted secondary structure ensembles. The density of branching is determined by the number and relative positions of 3-helix junctions, and is highly sensitive to the presence of rare higher-order junctions with 4 or more helices. Compact branching arises from a preponderance of base pairing between nucleotides close to each other in the primary sequence. The density of branching represents a degree of freedom optimized by viral RNA genomes in response to the evolutionary pressure to be packaged reliably. Several families of viruses are analyzed to delineate the effects of capsid geometry, size and charge stabilization on the selective pressure for RNA compactness. Compact branching has important implications for RNA folding and viral assembly.

  13. What are the Progenitors of Compace, Massive, Quiescent Galaxies at z (equals) 2.3? The Population of Massive Galaxies at z (greater than) 3 From NMBS AND CANDELS

    Science.gov (United States)

    Stefanon, Mauro; Marchesini, Danilo; Rudnick, Gregory H.; Brammer, Gabriel B.; Tease, Katherine Whitaker

    2013-01-01

    Using public data from the NEWFIRM Medium-Band Survey (NMBS) and the Cosmic Assembly Near-Infrared Deep Extragalactic Legacy Survey (CANDELS), we investigate the population of massive galaxies at z > 3. The main aim of this work is to identify the potential progenitors of z 2 compact, massive, quiescent galaxies (CMQGs), furthering our understanding of the onset and evolution of massive galaxies. Our work is enabled by high-resolution images from CANDELS data and accurate photometric redshifts, stellar masses, and star formation rates (SFRs) from 37-band NMBS photometry. The total number of massive galaxies at z > 3 is consistent with the number of massive, quiescent galaxies (MQGs) at z 2, implying that the SFRs for all of these galaxies must be much lower by z 2. We discover four CMQGs at z > 3, pushing back the time for which such galaxies have been observed. However, the volume density for these galaxies is significantly less than that of galaxies at z star-forming galaxies at z 3 that are compact (Re 1010.6M; these galaxies are likely to become members of the massive, quiescent, compact galaxy population at z 2. We evolve the stellar masses and SFRs of each individual z > 3 galaxy adopting five different star formation histories (SFHs) and studying the resulting population of massive galaxies at z = 2.3. We find that declining or truncated SFHs are necessary to match the observed number density of MQGs at z 2, whereas a constant delayed-exponential SFH would result in a number density significantly smaller than observed. All of our assumed SFHs imply number densities of CMQGs at z 2 that are consistent with the observed number density. Better agreement with the observed number density of CMQGs at z 2 is obtained if merging is included in the analysis and better still if star formation quenching is assumed to shortly follow the merging event, as implied by recent models of the formation of MQGs.

  14. Higgsless superconductivity from topological defects in compact BF terms

    Directory of Open Access Journals (Sweden)

    M. Cristina Diamantini

    2015-02-01

    Full Text Available We present a new Higgsless model of superconductivity, inspired from anyon superconductivity but P- and T-invariant and generalisable to any dimension. While the original anyon superconductivity mechanism was based on incompressible quantum Hall fluids as average field states, our mechanism involves topological insulators as average field states. In D space dimensions it involves a (D−1-form fictitious pseudovector gauge field which originates from the condensation of topological defects in compact low-energy effective BF theories. In the average field approximation, the corresponding uniform emergent charge creates a gap for the (D−2-dimensional branes via the Magnus force, the dual of the Lorentz force. One particular combination of intrinsic and emergent charge fluctuations that leaves the total charge distribution invariant constitutes an isolated gapless mode leading to superfluidity. The remaining massive modes organise themselves into a D-dimensional charged, massive vector. There is no massive Higgs scalar as there is no local order parameter. When electromagnetism is switched on, the photon acquires mass by the topological BF mechanism. Although the charge of the gapless mode (2 and the topological order (4 are the same as those of the standard Higgs model, the two models of superconductivity are clearly different since the origins of the gap, reflected in the high-energy sectors are totally different. In 2D this type of superconductivity is explicitly realised as global superconductivity in Josephson junction arrays. In 3D this model predicts a possible phase transition from topological insulators to Higgsless superconductors.

  15. Higgsless superconductivity from topological defects in compact BF terms

    Science.gov (United States)

    Diamantini, M. Cristina; Trugenberger, Carlo A.

    2015-02-01

    We present a new Higgsless model of superconductivity, inspired from anyon superconductivity but P- and T-invariant and generalisable to any dimension. While the original anyon superconductivity mechanism was based on incompressible quantum Hall fluids as average field states, our mechanism involves topological insulators as average field states. In D space dimensions it involves a (D - 1)-form fictitious pseudovector gauge field which originates from the condensation of topological defects in compact low-energy effective BF theories. In the average field approximation, the corresponding uniform emergent charge creates a gap for the (D - 2)-dimensional branes via the Magnus force, the dual of the Lorentz force. One particular combination of intrinsic and emergent charge fluctuations that leaves the total charge distribution invariant constitutes an isolated gapless mode leading to superfluidity. The remaining massive modes organise themselves into a D-dimensional charged, massive vector. There is no massive Higgs scalar as there is no local order parameter. When electromagnetism is switched on, the photon acquires mass by the topological BF mechanism. Although the charge of the gapless mode (2) and the topological order (4) are the same as those of the standard Higgs model, the two models of superconductivity are clearly different since the origins of the gap, reflected in the high-energy sectors are totally different. In 2D this type of superconductivity is explicitly realised as global superconductivity in Josephson junction arrays. In 3D this model predicts a possible phase transition from topological insulators to Higgsless superconductors.

  16. Causality in 3D Massive Gravity Theories

    CERN Document Server

    Edelstein, Jose D; Kilicarslan, Ercan; Leoni, Matias; Tekin, Bayram

    2016-01-01

    We study the constraints coming from local causality requirement in various 2+1 dimensional dynamical theories of gravity. In Topologically Massive Gravity, with a single parity noninvariant massive degree of freedom, and in New Massive Gravity, with two massive spin-$2$ degrees of freedom, causality and unitarity are compatible with each other and they both require the Newton's constant to be negative. In their extensions, such as the Born-Infeld gravity and the minimal massive gravity the situation is similar and quite different from their higher dimensional counterparts, such as quadratic (e.g., Einstein-Gauss-Bonnet) or cubic theories, where causality and unitarity are in conflict.

  17. Compact orthogonal NMR field sensor

    Science.gov (United States)

    Gerald, II, Rex E.; Rathke, Jerome W [Homer Glen, IL

    2009-02-03

    A Compact Orthogonal Field Sensor for emitting two orthogonal electro-magnetic fields in a common space. More particularly, a replacement inductor for existing NMR (Nuclear Magnetic Resonance) sensors to allow for NMR imaging. The Compact Orthogonal Field Sensor has a conductive coil and a central conductor electrically connected in series. The central conductor is at least partially surrounded by the coil. The coil and central conductor are electrically or electro-magnetically connected to a device having a means for producing or inducing a current through the coil and central conductor. The Compact Orthogonal Field Sensor can be used in NMR imaging applications to determine the position and the associated NMR spectrum of a sample within the electro-magnetic field of the central conductor.

  18. Sub-millimeter galaxies as progenitors of compact quiescent galaxies

    CERN Document Server

    Toft, S; Magnelli, B; Karim, A; Zirm, A; Michalowski, M; Capak, P; Sheth, K; Schawinski, K; Krogager, J -K; Wuyts, S; Sanders, D; Man, A W S; Lutz, D; Staguhn, J; Berta, S; Mccracken, H; Krpan, J; Riechers, D

    2014-01-01

    Three billion years after the big bang (at redshift z=2), half of the most massive galaxies were already old, quiescent systems with little to no residual star formation and extremely compact with stellar mass densities at least an order of magnitude larger than in low redshift ellipticals, their descendants. Little is known about how they formed, but their evolved, dense stellar populations suggest formation within intense, compact starbursts 1-2 Gyr earlier (at 3compact quiescent galaxies at z=2 and a statistically well-understood sample of SMGs, we show that z=3-6 SMGs are consistent with being the progenitors of z=2 quiescent galaxies, matching their formation redshifts and their distributions of sizes, stellar masses and internal velocities. As...

  19. STABLE ISOTOPE GEOCHEMISTRY OF MASSIVE ICE

    Directory of Open Access Journals (Sweden)

    Yurij K. Vasil’chuk

    2016-01-01

    Full Text Available The paper summarises stable-isotope research on massive ice in the Russian and North American Arctic, and includes the latest understanding of massive-ice formation. A new classification of massive-ice complexes is proposed, encompassing the range and variabilityof massive ice. It distinguishes two new categories of massive-ice complexes: homogeneousmassive-ice complexes have a similar structure, properties and genesis throughout, whereasheterogeneous massive-ice complexes vary spatially (in their structure and properties andgenetically within a locality and consist of two or more homogeneous massive-ice bodies.Analysis of pollen and spores in massive ice from Subarctic regions and from ice and snow cover of Arctic ice caps assists with interpretation of the origin of massive ice. Radiocarbon ages of massive ice and host sediments are considered together with isotope values of heavy oxygen and deuterium from massive ice plotted at a uniform scale in order to assist interpretation and correlation of the ice.

  20. Professional Windows Embedded Compact 7

    CERN Document Server

    Phung, Samuel; Joubert, Thierry; Hall, Mike

    2011-01-01

    Learn to program an array of customized devices and solutions As a compact, highly efficient, scalable operating system, Windows Embedded Compact 7 (WEC7) is one of the best options for developing a new generation of network-enabled, media-rich, and service-oriented devices. This in-depth resource takes you through the benefits and capabilities of WEC7 so that you can start using this performance development platform today. Divided into several major sections, the book begins with an introduction and then moves on to coverage of OS design, application development, advanced application developm

  1. Compact monolithic capacitive discharge unit

    Science.gov (United States)

    Roesler, Alexander W.; Vernon, George E.; Hoke, Darren A.; De Marquis, Virginia K.; Harris, Steven M.

    2007-06-26

    A compact monolithic capacitive discharge unit (CDU) is disclosed in which a thyristor switch and a flyback charging circuit are both sandwiched about a ceramic energy storage capacitor. The result is a compact rugged assembly which provides a low-inductance current discharge path. The flyback charging circuit preferably includes a low-temperature co-fired ceramic transformer. The CDU can further include one or more ceramic substrates for enclosing the thyristor switch and for holding various passive components used in the flyback charging circuit. A load such as a detonator can also be attached directly to the CDU.

  2. The RMS Survey: Resolving kinematic distance ambiguities towards a sample of compact HII regions using HI absorption

    CERN Document Server

    Urquhart, J S; Lumsden, S L; Oudmaijer, R D; Moore, T J T; Mottram, J C; Cooper, H D B; Mottram, M; Rogers, H C

    2011-01-01

    We present high-resolution HI data obtained using the Australia Telescope Compact Array to resolve the near/far distance ambiguities towards a sample of compact HII regions from the Red MSX Source (RMS) survey. The high resolution data are complemented with lower resolution archival HI data extracted from the Southern and VLA Galactic Plane surveys. We resolve the distance ambiguity for nearly all of the 105 sources where the continuum was strong enough to allow analysis of the HI absorption line structure. This represents another step in the determination of distances to the total RMS sample, which with over 1,000 massive young stellar objects and compact HII regions, is the largest and most complete sample of its kind. The full sample will allow the distribution of massive star formation in the Galaxy to be examined.

  3. Compaction dynamics of crunchy granular material

    Directory of Open Access Journals (Sweden)

    Guillard François

    2017-01-01

    Full Text Available Compaction of brittle porous material leads to a wide variety of densification patterns. Static compaction bands occurs naturally in rocks or bones, and have important consequences in industry for the manufacturing of powder tablets or metallic foams for example. Recently, oscillatory compaction bands have been observed in brittle porous media like snow or cereals. We will discuss the great variety of densification patterns arising during the compaction of puffed rice, including erratic compaction at low velocity, one or several travelling compaction bands at medium velocity and homogeneous compaction at larger velocity. The conditions of existence of each pattern are studied thanks to a numerical spring lattice model undergoing breakage and is mapped to the phase diagram of the patterns based on dimensionless characteristic quantities. This also allows to rationalise the evolution of the compaction behaviour during a single test. Finally, the localisation of compaction bands is linked to the strain rate sensitivity of the material.

  4. New Ultra-Compact Dwarf Galaxies in Clusters

    Science.gov (United States)

    Kohler, Susanna

    2017-02-01

    How do ultra-compact dwarf galaxies (UCDs) galaxies that are especially small and dense form and evolve? Scientists have recently examined distant galaxy clusters, searching for more UCDs to help us answer this question.Origins of DwarfsIn recent years we have discovered a growing sample of small, very dense galaxies. Galaxies that are tens to hundreds of light-years across, with masses between a million and a billion solar masses, fall into category of ultra-compact dwarfs (UCDs).An example of an unresolved compact object from the authors survey that is likely an ultra-compact dwarf galaxy. [Adapted from Zhang Bell 2017]How do these dense and compact galaxies form? Two possibilities are commonly suggested:An initially larger galaxy was tidally stripped during interactions with other galaxies in a cluster, leaving behind only its small, dense core as a UCD.UCDs formed as compact galaxies at very early cosmic times. The ones living in a massive dark matter halo may have been able to remain compact over time, evolving into the objectswe see today.To better understand which of these formation scenarios applies to which galaxies, we need a larger sample size! Our census of UCDs is fairly limited and because theyare small and dim, most of the ones weve discovered are in the nearby universe. To build a good sample, we need to find UCDs at higher redshifts as well.A New SampleIn a recent study, two scientists from University of Michigan have demonstrated how we might find more UCDs. Yuanyuan Zhang (also affiliated with Fermilab) and Eric Bell used the Cluster Lensing and Supernova Survey with Hubble (CLASH) to search 17 galaxy clusters at intermediate redshifts of 0.2 z 0.6, looking for unresolved objects that might be UCDs.The mass and size distributions of the UCD candidates reported in this study, in the context of previously known nuclear star clusters, globular clusters (GCs), UCDs, compact elliptical galaxies (cEs), and dwarf galaxies. [Zhang Bell 2017]Zhang and

  5. Quantization of massive scalar fields over static black string backgrounds

    CERN Document Server

    Piedra, Owen Pavel Fernandez

    2007-01-01

    The renormalized mean value of the corresponding components of the Energy-Momentum tensor for massive scalar fields coupled to an arbitrary gravitational field configuration having cylindrical symmetry are analytically evaluated using the Schwinger-DeWitt approximation, up to second order in the inverse mass value. The general results are employed to explicitly derive compact analytical expressions for the Energy-Momentum tensor in the particular background of the Black-String spacetime. In the case of the Black String considered in this work, we proof that a violation of the weak energy condition occur at the horizon of the space-time for values of the coupling constant, that include as particular cases the most interesting of minimal and conformal coupling.

  6. Observing the onset of outflow collimation in a massive protostar

    CERN Document Server

    Carrasco-González, C; Cantó, J; Curiel, S; Surcis, G; Vlemmings, W H T; van Langevelde, H J; Goddi, C; Anglada, G; Kim, S -W; Kim, J -S; Gómez, J F

    2015-01-01

    The current paradigm of star formation through accretion disks, and magnetohydrodynamically driven gas ejections, predicts the development of collimated outflows, rather than expansion without any preferential direction. We present radio continuum observations of the massive protostar W75N(B)-VLA 2, showing that it is a thermal, collimated ionized wind and that it has evolved in 18 years from a compact source into an elongated one. This is consistent with the evolution of the associated expanding water-vapor maser shell, which changed from a nearly circular morphology, tracing an almost isotropic outflow, to an elliptical one outlining collimated motions. We model this behavior in terms of an episodic, short-lived, originally isotropic, ionized wind whose morphology evolves as it moves within a toroidal density stratification.

  7. Massive Star Evolution Nucleosynthesis and Nuclear Reaction Rate Uncertainties

    CERN Document Server

    Heger, A; Rauscher, T; Hoffman, R D; Boyes, M M

    2002-01-01

    We present a nucleosynthesis calculation of a 25 solar mass star of solar composition that includes all relevant isotopes up to polonium. In particular, all stable isotopes and necessary nuclear reaction rates are covered. We follow the stellar evolution from hydrogen burning till iron core collapse and simulate the explosion using a ``piston'' approach. We discuss the influence of two key nuclear reaction rates, C12(a,g) and Ne22(a,n), on stellar evolution and nucleosynthesis. The former significantly influences the resulting core sizes (iron, silicon, oxygen) and the overall presupernova structure of the star. It thus has significant consequences for the supernova explosion itself and the compact remnant formed. The later rate considerably affects the s-process in massive stars and we demonstrate the changes that different currently suggested values for this rate cause.

  8. Galileons Coupled to Massive Gravity: General Analysis and Cosmological Solutions

    CERN Document Server

    Goon, Garrett; Hinterbichler, Kurt; Mukohyama, Shinji; Trodden, Mark

    2014-01-01

    We further develop the framework for coupling galileons and Dirac-Born-Infeld (DBI) scalar fields to a massive graviton while retaining both the non-linear symmetries of the scalars and ghost-freedom of the theory. The general construction is recast in terms of vielbeins which simplifies calculations and allows for compact expressions. Expressions for the general form of the action are derived, with special emphasis on those models which descend from maximally symmetric spaces. We demonstrate the existence of maximally symmetric solutions to the fully non-linear theory and analyze their spectrum of quadratic fluctuations. Finally, we consider self-accelerating cosmological solutions and study their perturbations, showing that the vector and scalar modes have vanishing kinetic terms.

  9. Considerações gerais sôbre os órgãos odoríferos sexuais dos machos dos Lepidópteros

    Directory of Open Access Journals (Sweden)

    Rudolf Barth

    1953-12-01

    Full Text Available São determinadas as seguintes regras sôbre a função dos órgãos odoríferos dos machos dos Lepidópteros: l.ª regra: A secreção das glândulas age em forma de gás sobre a fêmea diminuindo a reação normal de fuga e provocando a disposição e preparação para a copulação. 2.ª regra: Os órgãos odoríferos nos machos de um grupo de espécies parentes encontram-se constantemente nos mesmos órgãos possuindo o mesmo tipo de estrutura (constância orgânica . 3.ª regra: As partes quitinosas (escamas odoríferas, cerdas distribuidoras, inserções etc. são especificadas para cada espécie (constância de forma. 4.ª regra: O grau de desenvolvimento e com isto o grau de eficiência dos órgãos odoríferos dos Lepidópteros noturnos é sempre mais elevado do que os dos diurnos.

  10. The MACHO Project LMC Variable Star Inventory; 4, Multimode RR Lyrae Stars, Distance to the LMC and Age of the Oldest Stars

    CERN Document Server

    Alcock, C B; Alves, D R; Axelrod, T S; Becker, A C; Bennett, D P; Cook, K H; Freeman, K C; Griest, K; Guern, J A; Lehner, M J; Marshall, S L; Minniti, D; Peterson, B A; Pratt, M R; Quinn, P J; Rodgers, A W; Sutherland, W; Welch, D L

    1996-01-01

    We report the discovery of 73 double-mode RR Lyrae (RRd) stars in fields near the bar of the LMC. The stars are detected among the MACHO database of short-period variables that currently contains about 7900 RR Lyrae stars. Fundamental periods (P_0) for these stars are found in the range 0.46-0.55 days and first overtone-to-fundamental period ratios are found to be in the range 0.742 < P_1/P_0 < 0.748. A significant fraction of our current sample have period ratios smaller than any previously discovered RRd variables. We present mean magnitudes, colors, and lightcurve properties for all LMC RRd stars detected to date. The range in period ratios is unexpectedly large. We present a determination of absolute magnitudes for these stars based primarily on pulsation theory and the assumption that all observed stars are at the fundamental blue edge (FBE) of the instability strip. Comparison of the calibrated MACHO V and R_KC photometry with these derived absolute magnitudes yields an absorption-corrected distan...

  11. Susceptibility and morbidity between male and female Swiss mice infected with Angiostrongylus costaricensis: Susceptibilidade e morbidade entre camundongos Swiss machos e fêmeas infectados com Angiostrongylus costaricensis

    Directory of Open Access Journals (Sweden)

    Márcia B. Mentz

    2010-10-01

    Full Text Available The gender of vertebrate hosts may affect the outcome of parasitic infections. An experimental murine infection with Angiostrongylus costaricensis was followed with determinations of body weight, fecal larval elimination, number and length of adult worms, number of macroscopic intestinal lesions, and mortality. Groups of male and female Swiss mice were infected with 10 3rd-stage A. costaricensis larvae per animal. The results indicate there are no significant differences related to gender of the host, except for higher length of worms developed in male mice.O sexo dos hospedeiros vertebrados pode influenciar no resultado de infecções parasitárias. A infecção experimental de camundongos com Angiostrongylus costaricensis foi acompanhada com observação do peso corporal, eliminação de larvas nas fezes, número e comprimento dos vermes adultos, número de lesões macroscópicas nos intestinos e mortalidade. Grupos de camundongos Swiss machos e fêmeas foram infectados cada um com 10 larvas de terceiro estágio de A. costaricensis. Os resultados indicam que não há diferenças significativas relacionados ao sexo dos hospedeiros, exceto pelo maior comprimento dos vermes nos hospedeiros machos.

  12. Experiencias de seguimiento de rastros por los machos de boa arco iris Epicrates cenchria alvarezi (Serpentes: Boidae mediado por mensajes químicos

    Directory of Open Access Journals (Sweden)

    Briguera, Verónica

    1997-01-01

    Full Text Available En el presente trabajo probamos la habilidad de los machos de Epicrates cenchria alvarezi para encontrar y seguir señales químicas depositadas en el sustrato como rastros de olor y examinamos el posible origen de la huella química. Los machos parecen rastrear a las hembras si éstas tienen obstáculos en los que propulsarse y en donde dejar el rastro químico. Los resultados sugieren que la piel de las hembras es una fuente probable de las señales olorosas. In some species of snakes it has been demostrated the ability of males to found and follow chemical signals deposited over sustrate as odor trails. In this paper we tested this ability in males of Epicrates cenchria alvarezi and we also examined the possible source of the chemical signals. Males seem to follow better the trails if females have obstacles to propel herselfs and where to lie a chemical trail. Results suggest that the skin of females is the probable source of the chemical signals.

  13. Prospects for early localization of gravitational-wave signals from compact binary coalescences with advanced detectors

    OpenAIRE

    Manzotti, Alessandro; Dietz, Alexander

    2012-01-01

    A leading candidate source of detectable gravitational waves is the inspiral and merger of pairs of stellar-mass compact objects. The advanced LIGO and advanced Virgo detectors will allow scientists to detect inspiral signals from more massive systems and at earlier times in the detector band, than with first generation detectors. The signal from a coalescence of two neutron stars is expected to stay in the sensitive band of advanced detectors for several minutes, thus allowing detection befo...

  14. Frequency stability of a tunable diode laser mounted in a compact Stirling cycle cooler

    Science.gov (United States)

    Durso, Santo S.; May, R. D.; Tuchscherer, M. A.; Webster, C. R.

    1989-01-01

    A tunable diode laser (TDL) has been operated with a compact lightweight closed-cycle Stirling cooler. The laser linewidth has been measured near 80 K and found to be about half of that when using more massive closed-cycle coolers. Novel applications include balloon-borne and aircraft-adapted instruments, where size, weight, and power requirements place stringent demands on necessary TDL cooling systems.

  15. Cosmological perturbations in massive bigravity

    Energy Technology Data Exchange (ETDEWEB)

    Lagos, Macarena; Ferreira, Pedro G., E-mail: m.lagos13@imperial.ac.uk, E-mail: p.ferreira1@physics.ox.ac.uk [Astrophysics, University of Oxford, DWB, Keble road, Oxford OX1 3RH (United Kingdom)

    2014-12-01

    We present a comprehensive analysis of classical scalar, vector and tensor cosmological perturbations in ghost-free massive bigravity. In particular, we find the full evolution equations and analytical solutions in a wide range of regimes. We show that there are viable cosmological backgrounds but, as has been found in the literature, these models generally have exponential instabilities in linear perturbation theory. However, it is possible to find stable scalar cosmological perturbations for a very particular choice of parameters. For this stable subclass of models we find that vector and tensor perturbations have growing solutions. We argue that special initial conditions are needed for tensor modes in order to have a viable model.

  16. Massive hiatal hernia in children.

    Science.gov (United States)

    al-Arfaj, A L; Khwaja, M S; Upadhyaya, P

    1991-08-01

    Ten children had massive hiatal hernias repaired between January 1982 and February 1991. Their clinical presentation, association with other congenital abnormalities, and postoperative complications were different from those seen in adults. Vomiting (n = 7) and anaemia (n = 7) were the most common symptoms, followed by respiratory distress (n = 5), cough (n = 3), and regurgitation (n = 3). Abdominal pain was uncommon. The clinical diagnosis was confirmed in seven cases by barium meal examination. The most common operation was Nissen's fundoplication (n = 7); the hiatus alone was repaired in the remainder. Five patients developed postoperative complications and two died probably as a result of delay in diagnosis and associated malformations.

  17. The Compact Project: Final Report.

    Science.gov (United States)

    National Alliance of Business, Inc., Washington, DC.

    The National Alliance of Business (NAB) surveyed the 12 sites that participated in the Compact Project to develop and implement programs of business-education collaboration. NAB studied start-up activities, key players, conditions for collaboration, accomplishments, challenges, and future plans. Program outcomes indicated that building successful…

  18. JACKSON'S THEOREM FOR COMPACT GROUPS

    Institute of Scientific and Technical Information of China (English)

    H. Vaezi; S. F. Rzaev

    2002-01-01

    In this article we consider the generalized shift operator defined by(Sh.f)(g) = ∫Gf (tut-1g)dton compact group G and by help of this operator we define "Spherical" modulus of continuity. So we proveStechkin and Jackson type theorems.

  19. Compact Photon Source Conceptual Design

    Energy Technology Data Exchange (ETDEWEB)

    Degtyarenko, Pavel V. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Wojtsekhowski, Bogdan B. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

    2016-04-01

    We describe options for the production of an intense photon beam at the CEBAF Hall D Tagger facility, needed for creating a high-quality secondary K 0 L delivered to the Hall D detector. The conceptual design for the Compact Photon Source apparatus is presented.

  20. DNA compaction by nonbinding macromolecules

    NARCIS (Netherlands)

    Vries, de R.J.

    2012-01-01

    Compaction of DNA by nonbinding macromolecules such as uncharged flexible polymer chains and negatively charged globular proteins is thought to have various applications in biophysics, for example in the formation of a nucleoid structure in bacteria. A simple experimental model that has been very

  1. Dynamics of a compact operator

    CERN Document Server

    Lim, Teck-Cheong

    2010-01-01

    Let $T:X\\to X$ be a compact linear (or more generally affine) operator from a Banach space into itself. For each $x\\in X$, the sequence of iterates $T^nx, n=0,1,...$ and its averages $\\frac{1}{k}\\sum_{k=0}^nT^{k-1}x, n=0,1,...$ are either bounded or approach infinity.

  2. DNA compaction by nonbinding macromolecules

    NARCIS (Netherlands)

    Vries, de R.J.

    2012-01-01

    Compaction of DNA by nonbinding macromolecules such as uncharged flexible polymer chains and negatively charged globular proteins is thought to have various applications in biophysics, for example in the formation of a nucleoid structure in bacteria. A simple experimental model that has been very we

  3. Fuzzy Soft Compact Topological Spaces

    Directory of Open Access Journals (Sweden)

    Seema Mishra

    2016-01-01

    Full Text Available In this paper, we have studied compactness in fuzzy soft topological spaces which is a generalization of the corresponding concept by R. Lowen in the case of fuzzy topological spaces. Several basic desirable results have been established. In particular, we have proved the counterparts of Alexander’s subbase lemma and Tychonoff theorem for fuzzy soft topological spaces.

  4. On sequential countably compact topological semigroups

    CERN Document Server

    Gutik, Oleg V; Repovš, Dušan

    2008-01-01

    We study topological and algebraic properties of sequential countably compact topological semigroups similar to compact topological semigroups. We prove that a sequential countably compact topological semigroup does not contain the bicyclic semigroup. Also we show that the closure of a subgroup in a sequential countably compact topological semigroup is a topological group, that the inversion in a Clifford sequential countably compact topological semigroup is continuous and we prove the analogue of the Rees-Suschkewitsch Theorem for simple regular sequential countably compact topological semigroups.

  5. Flow Control in a Compact Inlet

    Science.gov (United States)

    Vaccaro, John C.

    2011-12-01

    An experimental investigation of flow control, via various control jets actuators, was undertaken to eliminate separation and secondary flows in a compact inlet. The compact inlet studied was highly aggressive with a length-to-diameter ratio of 1.5. A brand new facility was designed and built to enable various actuation methodologies as well as multiple measurement techniques. Techniques included static surface pressure, total pressure, and stereoscopic particle image velocimetry. Experimental data were supplemented with numerical simulations courtesy of Prof. Kenneth Jansen, Dr. Onkar Sahni, and Yi Chen. The baseline flow field was found to be dominated by two massive separations and secondary flow structures. These secondary structures were present at the aerodynamic interface plane in the form of two counter-rotating vortices inducing upwash along centerline. A dominant shedding frequency of 350 Hz was measured both at the aerodynamic interface plane and along the lower surface of the inlet. Flow control experiments started utilizing a pair of control jets placed in streamwise locations where flow was found to separate. Tests were performed for a range of inlet Mach numbers from 0.2 to 0.44. Steady and unsteady static pressure measurements along the upper and lower walls of the duct were performed for various combinations of actuation. The parameters that were tested include the control jets momentum coefficient, their blowing ratio, the actuation frequency, as well as different combinations of jets. It was shown that using mass flux ratio as a criterion to define flow control is not sufficient, and one needs to provide both the momentum coefficient and the blowing ratio to quantify the flow control performance. A detailed study was undertaken on controlling the upstream separation point for an inlet Mach number of 0.44. Similar to the baseline flow field, the flow field associated with the activation of a two-dimensional control jet actuator was dominated by

  6. A Comprehensive Analysis of the Magnetic Standard Star HD 94660: Host of a Massive Compact Companion?

    CERN Document Server

    Bailey, J D; Landstreet, J D

    2015-01-01

    Detailed information about the magnetic geometry, atmospheric abundances and radial velocity variations has been obtained for the magnetic standard star HD 94660 based on high-dispersion spectroscopic and spectropolarimetric observations from the UVES, HARPSpol and ESPaDOnS instruments. We perform a detailed chemical abundance analysis using the spectrum synthesis code zeeman for a total of 17 elements. Using both line-of-sight and surface magnetic field measurements, we derive a simple magnetic field model that consists of dipole, quadrupole and octupole components. The observed magnetic field variations of HD 94660 are complex and suggest an inhomogeneous distribution of chemical elements over the stellar surface. This inhomogeneity is not reflected in the abundance analysis, from which all available spectra are modelled, but only a mean abundance is reported for each element. The derived abundances are mostly non-solar, with striking overabundances of Fe-peak and rare-earth elements. Of note are the clear ...

  7. Compaction and relaxation of biofilms

    KAUST Repository

    Valladares Linares, R.

    2015-06-18

    Operation of membrane systems for water treatment can be seriously hampered by biofouling. A better characterization of biofilms in membrane systems and their impact on membrane performance may help to develop effective biofouling control strategies. The objective of this study was to determine the occurrence, extent and timescale of biofilm compaction and relaxation (decompaction), caused by permeate flux variations. The impact of permeate flux changes on biofilm thickness, structure and stiffness was investigated in situ and non-destructively with optical coherence tomography using membrane fouling monitors operated at a constant crossflow velocity of 0.1 m s−1 with permeate production. The permeate flux was varied sequentially from 20 to 60 and back to 20 L m−2 h−1. The study showed that the average biofilm thickness on the membrane decreased after elevating the permeate flux from 20 to 60 L m−2 h−1 while the biofilm thickness increased again after restoring the original flux of 20 L m−2 h−1, indicating the occurrence of biofilm compaction and relaxation. Within a few seconds after the flux change, the biofilm thickness was changed and stabilized, biofilm compaction occurred faster than the relaxation after restoring the original permeate flux. The initial biofilm parameters were not fully reinstated: the biofilm thickness was reduced by 21%, biofilm stiffness had increased and the hydraulic biofilm resistance was elevated by 16%. Biofilm thickness was related to the hydraulic biofilm resistance. Membrane performance losses are related to the biofilm thickness, density and morphology, which are influenced by (variations in) hydraulic conditions. A (temporarily) permeate flux increase caused biofilm compaction, together with membrane performance losses. The impact of biofilms on membrane performance can be influenced (increased and reduced) by operational parameters. The article shows that a (temporary) pressure increase leads to more

  8. Radio observations of massive stars

    CERN Document Server

    Blomme, Ronny

    2011-01-01

    Detectable radio emission occurs during almost all phases of massive star evolution. I will concentrate on the thermal and non-thermal continuum emission from early-type stars. The thermal radio emission is due to free-free interactions in the ionized stellar wind material. Early ideas that this would lead to an easy and straightforward way of measuring the mass-loss rates were thwarted by the presence of clumping in the stellar wind. Multi-wavelength observations provide important constraints on this clumping, but do not allow its full determination. Non-thermal radio emission is associated with binarity. This conclusion was already known for some time for Wolf-Rayet stars and in recent years it has become clear that it is also true for O-type stars. In a massive-star binary, the two stellar winds collide and around the shocks a fraction of the electrons are accelerated to relativistic speeds. Spiralling in the magnetic field these electrons emit synchrotron radiation, which we detect as non-thermal radio em...

  9. Solid Holography and Massive Gravity

    CERN Document Server

    Alberte, Lasma; Khmelnitsky, Andrei; Pujolas, Oriol

    2015-01-01

    Momentum dissipation is an important ingredient in condensed matter physics that requires a translation breaking sector. In the bottom-up gauge/gravity duality, this implies that the gravity dual is massive. We start here a systematic analysis of holographic massive gravity (HMG) theories, which admit field theory dual interpretations and which, therefore, might store interesting condensed matter applications. We show that there are many phases of HMG that are fully consistent effective field theories and which have been left overlooked in the literature. The most important distinction between the different HMG phases is that they can be clearly separated into solids and fluids. This can be done both at the level of the unbroken spacetime symmetries as well as concerning the elastic properties of the dual materials. We extract the modulus of rigidity of the solid HMG black brane solutions and show how it relates to the graviton mass term. We also consider the implications of the different HMGs on the electric...

  10. CANDELS+3D-HST: compact SFGs at z~2-3, the progenitors of the first quiescent galaxies

    CERN Document Server

    Barro, G; Perez-Gonzalez, P G; Pacifici, C; Trump, J R; Koo, D C; Wuyts, S; Guo, Y; Bell, E; Dekel, A; Porter, L; Primack, J; Ferguson, H; Ashby, M; Caputi, K; Ceverino, D; Croton, D; Fazio, G; Giavalisco, M; Hsu, L; Kocevski, D; Koekemoer, A; Kurczynski, P; Kollipara, P; Lee, J; McIntosh, D; McGrath, E; Moody, C; Somerville, R; Papovich, C; Salvato, M; Santini, P; Williams, C C; Willner, S; Zolotov, A

    2013-01-01

    We analyze the star-forming and structural properties of 45 massive (log(M/Msun)>10) compact star-forming galaxies (SFGs) at 2compact quiescent galaxies at z~2. The optical/NIR and far-IR Spitzer/Herschel colors indicate that most compact SFGs are heavily obscured. Nearly half (47%) host an X-ray bright AGN. In contrast, only about 10% of other massive galaxies at that time host AGNs. Compact SFGs have centrally-concentrated light profiles and spheroidal morphologies similar to quiescent galaxies, and are thus strikingly different from other SFGs. Most compact SFGs lie either within the SFR-M main sequence (65%) or below (30%), on the expected evolutionary path towards quiescent galaxies. These results show conclusively that galaxies become more compact before they lose their gas and dust, quenching star formation. Using extensive HST photometry from CANDELS and grism spectroscopy from the 3D-HST survey, we model their stellar populations with either expon...

  11. A Massive Spiral Galaxy in the Zone of Avoidance

    CERN Document Server

    Donley, J L; Koribalski, B S; Kraan-Korteweg, R C; Schröder, A; Staveley-Smith, L

    2006-01-01

    We report the discovery of a very HI-massive disk galaxy, HIZOA J0836-43, at a velocity of v_hel = 10689 km/s, corresponding to a distance of 148 Mpc (assuming H_0=75 km/s/Mpc). It was found during the course of a systematic HI survey of the southern Zone of Avoidance (|b| < 5 deg) with the multibeam system at the 64m Parkes radio telescope. Follow-up observations with the Australia Telescope Compact Array (ATCA) reveal an extended HI disk. We derive an HI mass of 7.5 x 10^10 Msun. Using the HI radius, we estimate a total dynamical mass of 1.4 x 10^12 Msun, similar to the most massive known disk galaxies such as Malin 1. HIZOA J0836-43 lies deep in the Zone of Avoidance (l, b = 262.48 deg, -1.64 deg) where the optical extinction is very high, A_B = 9.8. However, in the near-infrared wavebands, where the extinction is considerably lower, HIZOA J0836-43 is clearly detected by both DENIS and 2MASS. Deep AAT near-infrared (Ks and H-band) images show that HIZOA J0836-43 is an inclined disk galaxy with a promine...

  12. Asymmetric core-collapse of rapidly-rotating massive star

    CERN Document Server

    Gilkis, Avishai

    2016-01-01

    Non-axisymmetric features are found in the core-collapse of a rapidly-rotating massive star, which may have important implications for magnetic field amplification and production of a bipolar outflow that can explode the star, as well as for r-process nucleosynthesis and natal kicks. The collapse of an evolved rapidly-rotating massive star is followed in three-dimensional hydrodynamic simulations using the FLASH code with neutrino leakage. A rotating proto-neutron star (PNS) forms with a non-zero linear velocity. This process might contribute to the natal kick of the remnant compact object. The PNS is surrounded by a turbulent medium, where high shearing is likely to amplify magnetic fields, which in turn can drive a bipolar outflow. Neutron-rich material in the PNS vicinity may induce strong r-process nucleosynthesis. The rapidly-rotating PNS possesses a rotational energy of E>10foe, some of which may possibly be deposited later on in the SN ejecta through a magnetar spin down process. These processes may be...

  13. PROTOSTELLAR OUTFLOW HEATING IN A GROWING MASSIVE PROTOCLUSTER

    Energy Technology Data Exchange (ETDEWEB)

    Wang Ke; Wu Yuefang; Zhang Huawei [Department of Astronomy, School of Physics, Peking University, Beijing 100871 (China); Zhang Qizhou [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Li Huabai, E-mail: kwang@cfa.harvard.edu [Max-Planck Institute for Astronomy, Koenigstuhl 17, D-69117 Heidelberg (Germany)

    2012-02-15

    The dense molecular clump P1 in the infrared dark cloud complex G28.34+0.06 harbors a massive protostellar cluster at its extreme youth. Our previous Submillimeter Array observations revealed several jet-like CO outflows emanating from the protostars, indicative of intense accretion and potential interaction with ambient natal materials. Here, we present the Expanded Very Large Array spectral line observations toward P1 in the NH{sub 3} (J,K) = (1,1), (2,2), (3,3) lines, as well as H{sub 2}O and class I CH{sub 3}OH masers. Multiple NH{sub 3} transitions reveal the heated gas widely spread in the 1 pc clump. The temperature distribution is highly structured; the heated gas is offset from the protostars, and morphologically matches the outflows very well. Hot spots of spatially compact, spectrally broad NH{sub 3} (3,3) emission features are also found coincident with the outflows. A weak NH{sub 3} (3,3) maser is discovered at the interface between an outflow jet and the ambient gas. These findings suggest that protostellar heating may not be effective in suppressing fragmentation during the formation of massive cores.

  14. The massive stellar population of W49: A spectroscopic survey

    Science.gov (United States)

    Wu, Shi-Wei; Bik, Arjan; Bestenlehner, Joachim M.; Henning, Thomas; Pasquali, Anna; Brandner, Wolfgang; Stolte, Andrea

    2016-05-01

    Context. Massive stars form on different scales that range from large, dispersed OB associations to compact, dense starburst clusters. The complex structure of regions of massive star formation and the involved short timescales provide a challenge for our understanding of their birth and early evolution. As one of the most massive and luminous star-forming region in our Galaxy, W49 is the ideal place to study the formation of the most massive stars. Aims: By classifying the massive young stars that are deeply embedded in the molecular cloud of W49, we aim to investigate and trace the star formation history of this region. Methods: We analyse near-infrared K-band spectroscopic observations of W49 from LBT/LUCI combined with JHK images obtained with NTT/SOFI and LBT/LUCI. Based on JHK-band photometry and K-band spectroscopy, the massive stars are placed in a Hertzsprung Russell diagram. By comparison with evolutionary models, their age and hence the star formation history of W49 can be investigated. Results: Fourteen O-type stars, as well as two young stellar objects (YSOs), are identified by our spectroscopic survey. Eleven O stars are main sequence stars with subtypes ranging from O3 to O9.5 and masses ranging from ~20 M⊙ to ~120 M⊙. Three of the O stars show strong wind features and are considered to be Of-type supergiants with masses beyond 100 M⊙. The two YSOs show CO emission, which is indicative of the presence of circumstellar disks in the central region of the massive cluster. The age of the cluster is estimated as ~1.5 Myr, with star formation continuing in different parts of the region. The ionising photons from the central massive stars have not yet cleared the molecular cocoon surrounding the cluster. W49 is comparable to extragalactic star-forming regions, and it provides us with a unique chance to study a starburst in detail. Based on data acquired using the Large Binocular Telescope (LBT). The LBT is an international collaboration among

  15. The abundance of compact quiescent galaxies since z ˜ 0.6

    Science.gov (United States)

    Charbonnier, Aldée; Huertas-Company, Marc; Gonçalves, Thiago S.; Menéndez-Delmestre, Karín; Bundy, Kevin; Galliano, Emmanuel; Moraes, Bruno; Makler, Martín; Pereira, Maria E. S.; Erben, Thomas; Hildebrandt, Hendrik; Shan, Huan-Yuan; Caminha, Gabriel B.; Grossi, Marco; Riguccini, Laurie

    2017-08-01

    We set out to quantify the number density of quiescent massive compact galaxies at intermediate redshifts. We determine structural parameters based on i-band imaging using the Canada-France-Hawaii Telescope (CFHT) equatorial Sloan Digital Sky Survey (SDSS) Stripe 82 (CS82) survey (˜170 deg2) taking advantage of an exquisite median seeing of ˜0.6 arcsec. We select compact massive (M⋆ > 5 × 1010 M⊙) galaxies within the redshift range of 0.2 10. We systematically measure a factor of ˜5 more compacts at the same redshift than what was previously reported on smaller fields with Hubble Space Telescope (HST) imaging, which are more affected by cosmic variance. This means that the decrease in number density from z ˜ 1.5 to z ˜ 0.2 might be only of a factor of ˜2-5, significantly smaller than what was previously reported. This supports progenitor bias as the main contributor to the size evolution. This milder decrease is roughly compatible with the predictions from recent numerical simulations. Only the most extreme compact galaxies, with Reff 1010.7 M⊙, appear to drop in number by a factor of ˜20 and hence likely experience a noticeable size evolution.

  16. Imaging of Three Possible Low Redshift Analogs to High Redshift Compact Red Galaxies

    CERN Document Server

    Shih, Hsin-Yi

    2011-01-01

    As part of a larger program to identify and characterize possible low-redshift analogs to massive compact red galaxies found at high redshift, we have examined the morphologies of three low-redshift compact galaxies drawn from the sample of Trujillo et al. (2009). Using deeper and higher resolution images, we have found faint and relatively extensive outer structures in addition to the compact cores identified in the earlier measurements. One object appears to have a small companion that may be involved in an ongoing minor merger of the sort that could be responsible for building up the outer parts of these galaxies. The ages of the dominant stellar populations in these objects are found to be around 2--4 Gyr, in good agreement with the previous estimates. The presence of diffuse outer structures in these galaxies indicates that truly compact and massive red galaxies are exceedingly rare at low redshift. The relatively young stellar populations suggest that the accretion of the extensive outer material must o...

  17. Filter Bank Multicarrier for Massive MIMO

    OpenAIRE

    Farhang, Arman,; Marchetti, Nicola; Doyle, Linda E.; Farhang-Boroujeny, Behrouz

    2014-01-01

    This paper introduces filter bank multicarrier (FBMC) as a potential candidate in the application of massive MIMO communication. It also points out the advantages of FBMC over OFDM (orthogonal frequency division multiplexing) in the application of massive MIMO. The absence of cyclic prefix in FBMC increases the bandwidth efficiency. In addition, FBMC allows carrier aggregation straightforwardly. Self-equalization, a property of FBMC in massive MIMO that is introduced in this paper, has the im...

  18. Massive Gravity with N=1 local Supersymmetry

    CERN Document Server

    Malaeb, Ola

    2013-01-01

    A consistent theory of massive gravity, where the graviton acquires mass by spontaneously breaking diffeomorphism invariance, is now well established. We supersymmetrize this construction using N =1 fields. Coupling to N = 1 supergravity is done by applying the rules of tensor calculus to construct an action invariant under local N = 1 supersymmetry. The supersymmetric action is shown, at the quadratic level, to be free of ghosts and have as its spectrum a massive graviton, two gravitinos with different masses, and a massive vector.

  19. On the singularities of massive superstring amplitudes

    Energy Technology Data Exchange (ETDEWEB)

    Foda, O.

    1987-06-04

    Superstring one-loop amplitudes with massive external states are shown to be in general ill-defined due to internal on-shell propagators. However, we argue that since any massive string state (in the uncompactified theory) has a finite lifetime to decay into massless particles, such amplitudes are not terms in the perturbative expansion of physical S-matrix elements: These can be defined only with massless external states. Consistent massive amplitudes repuire an off-shell formalism.

  20. The antipodal sets of compact symmetric spaces

    National Research Council Canada - National Science Library

    Liu, Xingda; Deng, Shaoqiang

    2014-01-01

    We study the antipodal set of a point in a compact Riemannian symmetric space. It turns out that we can give an explicit description of the antipodal set of a point in any connected simply connected compact Riemannian symmetric space...

  1. Rate type isotach compaction of consolidated sandstone

    NARCIS (Netherlands)

    Waal, J.A. de; Thienen-Visser, K. van; Pruiksma, J.P.

    2015-01-01

    Laboratory experiments on samples from a consolidated sandstone reservoir are presented that demonstrate rate type compaction behaviour similar to that observed on unconsolidated sands and soils. Such rate type behaviour can have large consequences for reservoir compaction, surface subsidence and

  2. Warm compaction powder metallurgy of Cu

    Institute of Scientific and Technical Information of China (English)

    NGAI Tungwai Leo; WANG Shang-lin; LI Yuan-yuan; ZHOU Zho-yao; CHEN Wei-ping

    2005-01-01

    A series of experiments were carried out using different admixed lubricant contents,different compaction pressures and temperatures in order to study the warm compaction of copper powder.Results show that too much admixed lubricant will lead to the squeeze out of the lubricant from the compact during the warm compaction processing of Cu powder.Results also show that blisters can be found in sintered samples that contain lubricant less than 0.15% (mass fraction).Optimal warm compaction parameters for producing high density powder metallurgy copper material are obtained.Compacts with green density of 8.6 g/cm3 and a sintered density of 8.83 g/cm3 can be produced by warm compacting the Cu powder,which contains 0.2% admixed lubricant,and is compacted at 145 ℃ with a pressure of 700 Mpa.

  3. Compact wire array sources: power scaling and implosion physics.

    Energy Technology Data Exchange (ETDEWEB)

    Serrano, Jason Dimitri; Chuvatin, Alexander S. (Laboratoire du Centre National de la Recherche Scientifique Ecole Polytechnique, Palaiseau, France); Jones, M. C.; Vesey, Roger Alan; Waisman, Eduardo M.; Ivanov, V. V. (University of Nevada - Reno, Reno, NV); Esaulov, Andrey A. (University of Nevada - Reno, Reno, NV); Ampleford, David J.; Cuneo, Michael Edward; Kantsyrev, Victor Leonidovich (University of Nevada - Reno, Reno, NV); Coverdale, Christine Anne; Rudakov, L. I. (Icarus Research, Bethesda, MD); Jones, Brent Manley; Safronova, Alla S. (University of Nevada - Reno, Reno, NV); Vigil, Marcelino Patricio

    2008-09-01

    compare this to cylindrical array results in the context of a K-shell yield scaling model. We have also performed an initial study of compact 3 mm diameter cylindrical wire arrays, which are alternate candidates for a multi-pinch vacuum hohlraum concept. These massive 3.4 and 6 mg/cm loads may have been impacted by opacity, producing a maximum x-ray power of 7 TW at 4.5 MA, 45 ns. Future research directions in compact x-ray sources are discussed.

  4. Rotation and massive close binary evolution

    CERN Document Server

    Langer, N; Yoon, S -C; Hunter, I; Brott, I; Lennon, D J; de Mink, S E; Verheijdt, M

    2008-01-01

    We review the role of rotation in massive close binary systems. Rotation has been advocated as an essential ingredient in massive single star models. However, rotation clearly is most important in massive binaries where one star accretes matter from a close companion, as the resulting spin-up drives the accretor towards critical rotation. Here, we explore our understanding of this process, and its observable consequences. When accounting for these consequences, the question remains whether rotational effects in massive single stars are still needed to explain the observations.

  5. Megaloblastic anemia presenting with massive reversible splenomegaly.

    Science.gov (United States)

    Behera, Vineet; Randive, Makarand; Sharma, Praveen; Nair, Velu

    2015-06-01

    Megaloblastic anemia (MA) is a common disorder with varied manifestations. It generally results in mild to moderate splenomegaly which is due to sequestration of macrocytic erythrocytes in spleen. Massive splenomegaly is generally seen in infections, myeloproliferative diseases, neoplasms, storage disorders or hematological conditions; but is not heard of and has rarely been reported in MA. We discuss a case of massive splenomegaly who presented with symptomatic anemia and was found to have MA. He was extensive evaluated for all other causes of massive splenomegaly which was normal. Further, after a therapeutic trial of MA he showed a regression in spleen size confirming that the massive splenomegaly was attributable to MA.

  6. The origin of the most massive black holes at high-z: BlueTides and the next quasar frontier

    Science.gov (United States)

    Di Matteo, Tiziana; Croft, Rupert A. C.; Feng, Yu; Waters, Dacen; Wilkins, Stephen

    2017-06-01

    The growth of the most massive black holes in the early Universe, consistent with the detection of highly luminous quasars at z > 6 implies sustained, critical accretion of material to grow and power them. Given a black hole (BH) seed scenario, it is still uncertain which conditions in the early Universe allow the fastest BH growth. Large-scale hydrodynamical cosmological simulations of structure formation allow us to explore the conditions conducive to the growth of the earliest supermassive BHs. We use the cosmological hydrodynamic simulation BlueTides, which incorporates a variety of baryon physics in a (400 h-1Mpc)3 volume with 0.7 trillion particles to follow the earliest phases of BH critical growth. At z = 8 the most massive BHs (a handful) approach masses of 108 M_{⊙} with the most massive (with M_BH = 4 × 10^8 M_{⊙}) being found in an extremely compact (compared to present day) spheroid-dominated host galaxy. Examining the large-scale environment of hosts, we find that the initial tidal field is more important than overdensity in setting the conditions for early BH growth. In regions of low tidal fields gas accretes 'cold' on to the BH and falls along thin, radial filaments straight into the centre forming the most compact galaxies and most massive BHs at the earliest times. Regions of high tidal fields instead induce larger coherent angular momenta and influence the formation of the first population of massive compact discs. The extreme early growth depends on the early interplay of high gas densities and the tidal field that shapes the mode of accretion. Mergers may play a minor role in the formation of the first generation, rare massive BHs.

  7. Aspectos qualitativos da carcaça e da carne de machos braford superprecoces, desmamados aos 72 ou 210 dias de idade

    Directory of Open Access Journals (Sweden)

    Vaz Fabiano Nunes

    2002-01-01

    Full Text Available Este trabalho foi conduzido com o objetivo de estudar os aspectos qualitativos da carcaça e da carne de machos Braford (5/8 Hereford 3/8 Nelore desmamados em duas idades, aos 72 (T72 ou 210 (T210 dias. Utilizaram-se 36 bezerros, não castrados, os quais foram terminados em confinamento e abatidos aos quatorze meses de idade. Não houve diferença significativa para as porcentagens de músculo, gordura e osso, sendo que as médias entre os dois tratamentos para essas características foram de 63,29; 21,97; e 15,03%, respectivamente. O T72 apresentou maior relação músculo/osso (4,49 contra 4,02 que o T210, não existindo diferença entre os dois tratamentos para relação músculo + gordura/osso. A cor, textura e marmoreio da carne foram semelhantes entre os dois tratamentos, sendo os valores observados no T72 de 4,19; 3,31; e 5,75 pontos, respectivamente, e no T210 de 3,89; 3,63; e 5,63 pontos, citados na mesma ordem. A maciez da carne foi classificada como levemente acima da média nos dois tratamentos e a força de cizalhamento foi de 7,36 e 7,17 kg, respectivamente, para T72 e T210. Os animais do T72 apresentaram 6,32 e 5,97 pontos, respectivamente, para palatabilidade e suculência da carne; nos animais do T210, esses valores foram de 6,41 e 6,08 pontos. A quebra ao descongelamento da carne foi 4,84% e a quebra à cocção, de 28,97%, no T72, enquanto no T210 estes valores foram de 7,01 e 26,76%, citados na mesma ordem. Machos Braford desmamados aos 72 ou 210 dias de idade e abatidos aos quatorze meses de idade apresentaram carne com características sensoriais semelhantes, indicando que os dois manejos são adequados para a produção de machos superprecoces.

  8. The Kolmogorov-Riesz compactness theorem

    CERN Document Server

    Hanche-Olsen, Harald

    2009-01-01

    We show that the Arzela-Ascoli theorem and Kolmogorov compactness theorem both are consequences of a simple lemma on compactness in metric spaces. Their relation to Helly's theorem is discussed. The paper contains a detailed discussion on the historical background of the Kolmogorov compactness theorem.

  9. Equationally Compact Acts : Coproducts / Peeter Normak

    Index Scriptorium Estoniae

    Normak, Peeter

    1998-01-01

    In this article equational compactness of acts and its generalizations are discussed. As equational compactness does not carry over to coproducts a slight generalization of c-equational campactness is introduced. It is proved that a coproduct of acts is c-equationally compact if and only if all components are c-equationally campact

  10. Equationally Compact Acts : Coproducts / Peeter Normak

    Index Scriptorium Estoniae

    Normak, Peeter

    1998-01-01

    In this article equational compactness of acts and its generalizations are discussed. As equational compactness does not carry over to coproducts a slight generalization of c-equational campactness is introduced. It is proved that a coproduct of acts is c-equationally compact if and only if all components are c-equationally campact

  11. Formation and evolution of compact binaries

    NARCIS (Netherlands)

    Sluijs, Marcel Vincent van der

    2006-01-01

    In this thesis we investigate the formation and evolution of compact binaries. Chapters 2 through 4 deal with the formation of luminous, ultra-compact X-ray binaries in globular clusters. We show that the proposed scenario of magnetic capture produces too few ultra-compact X-ray binaries to explain

  12. Massive Parallel Quantum Computer Simulator

    CERN Document Server

    De Raedt, K; De Raedt, H; Ito, N; Lippert, T; Michielsen, K; Richter, M; Trieu, B; Watanabe, H; Lippert, Th.

    2006-01-01

    We describe portable software to simulate universal quantum computers on massive parallel computers. We illustrate the use of the simulation software by running various quantum algorithms on different computer architectures, such as a IBM BlueGene/L, a IBM Regatta p690+, a Hitachi SR11000/J1, a Cray X1E, a SGI Altix 3700 and clusters of PCs running Windows XP. We study the performance of the software by simulating quantum computers containing up to 36 qubits, using up to 4096 processors and up to 1 TB of memory. Our results demonstrate that the simulator exhibits nearly ideal scaling as a function of the number of processors and suggest that the simulation software described in this paper may also serve as benchmark for testing high-end parallel computers.

  13. Massive Variability Surveys from Venezuela

    CERN Document Server

    Briceño, C

    2003-01-01

    At the Venezuela National Astronomical Observatory we are carrying out variability surveys spanning many hundreds of square degrees near the celestial equator, using an 8k x 8k CCD Mosaic Camera optimized for drift-scanning on a 1m Schmidt telescope. Among the initial efforts was a project to obtain the first moderately deep, homogeneous sample of young stars over an area of ~180sqr.deg. encompassing the entire Orion OB1 association, one of the nearest and most active regions of star formation. The results show that variability is a powerful technique to identify pre-main sequence populations, specially in sparse areas devoid of gas and dust. We are currently developing a massive database, equipped with web-based data mining tools, that will make our data and results available to the astronomical community.

  14. Stable massive particles at colliders

    Energy Technology Data Exchange (ETDEWEB)

    Fairbairn, M.; /Stockholm U.; Kraan, A.C.; /Pennsylvania U.; Milstead, D.A.; /Stockholm U.; Sjostrand, T.; /Lund U.; Skands, P.; /Fermilab; Sloan, T.; /Lancaster U.

    2006-11-01

    We review the theoretical motivations and experimental status of searches for stable massive particles (SMPs) which could be sufficiently long-lived as to be directly detected at collider experiments. The discovery of such particles would address a number of important questions in modern physics including the origin and composition of dark matter in the universe and the unification of the fundamental forces. This review describes the techniques used in SMP-searches at collider experiments and the limits so far obtained on the production of SMPs which possess various colour, electric and magnetic charge quantum numbers. We also describe theoretical scenarios which predict SMPs, the phenomenology needed to model their production at colliders and interactions with matter. In addition, the interplay between collider searches and open questions in cosmology such as dark matter composition are addressed.

  15. Mixing in massive stellar mergers

    CERN Document Server

    Gaburov, E; Zwart, S Portegies

    2007-01-01

    The early evolution of dense star clusters is possibly dominated by close interactions between stars, and physical collisions between stars may occur quite frequently. Simulating a stellar collision event can be an intensive numerical task, as detailed calculations of this process require hydrodynamic simulations in three dimensions. We present a computationally inexpensive method in which we approximate the merger process, including shock heating, hydrodynamic mixing and mass loss, with a simple algorithm which is based on conservation laws and a basic qualitative understanding of the hydrodynamics of stellar mergers. The algorithm is based on Archimedes' principle, which dictates the distribution of the fluid in stable equilibrium situation. We calibrate and apply the method to mergers of massive stars, as these are expected to occur in young and dense star clusters. We find that mergers between spectral type B stars ($\\sim$10\\msun) result in substantial mixing, whereas mergers between stars of different sp...

  16. Derivative couplings in massive bigravity

    CERN Document Server

    Gao, Xian

    2016-01-01

    In this work we study the cosmological perturbations in massive bigravity in the presence of non-minimal derivative couplings. For this purpose we consider a specific subclass of Horndeski scalar-tensor interactions that live on the unique composite effective metric. For the viability of the model both metrics have to be dynamical. Nevertheless, the number of allowed kinetic terms is crucial. We adapt to the restriction of having one single kinetic term. After deriving the full set of equations of motion for flat Friedmann-Lemaitre-Robertson-Walker background, we study linear perturbations on top of it. We show explicitly that only four tensor, two vector and two scalar degrees of freedom propagate, one of which being the Horndeski scalar, while the Boulware-Deser ghost can be integrated out.

  17. Derivative couplings in massive bigravity

    Science.gov (United States)

    Gao, Xian; Heisenberg, Lavinia

    2016-03-01

    In this work we study the cosmological perturbations in massive bigravity in the presence of non-minimal derivative couplings. For this purpose we consider a specific subclass of Horndeski scalar-tensor interactions that live on the unique composite effective metric. For the viability of the model both metrics have to be dynamical. Nevertheless, the number of allowed kinetic terms is crucial. We adapt to the restriction of having one single kinetic term. After deriving the full set of equations of motion for flat Friedmann-Lemaitre-Robertson-Walker background, we study linear perturbations on top of it. We show explicitly that only four tensor, two vector and two scalar degrees of freedom propagate, one of which being the Horndeski scalar, while the Boulware-Deser ghost can be integrated out.

  18. C++ and Massively Parallel Computers

    Directory of Open Access Journals (Sweden)

    Daniel J. Lickly

    1993-01-01

    Full Text Available Our goal is to apply the software engineering advantages of object-oriented programming to the raw power of massively parallel architectures. To do this we have constructed a hierarchy of C++ classes to support the data-parallel paradigm. Feasibility studies and initial coding can be supported by any serial machine that has a C++ compiler. Parallel execution requires an extended Cfront, which understands the data-parallel classes and generates C* code. (C* is a data-parallel superset of ANSI C developed by Thinking Machines Corporation. This approach provides potential portability across parallel architectures and leverages the existing compiler technology for translating data-parallel programs onto both SIMD and MIMD hardware.

  19. Massive Black Holes and Galaxies

    CERN Document Server

    CERN. Geneva

    2016-01-01

    Evidence has been accumulating for several decades that many galaxies harbor central mass concentrations that may be in the form of black holes with masses between a few million to a few billion time the mass of the Sun. I will discuss measurements over the last two decades, employing adaptive optics imaging and spectroscopy on large ground-based telescopes that prove the existence of such a massive black hole in the Center of our Milky Way, beyond any reasonable doubt. These data also provide key insights into its properties and environment. Most recently, a tidally disrupting cloud of gas has been discovered on an almost radial orbit that reached its peri-distance of ~2000 Schwarzschild radii in 2014, promising to be a valuable tool for exploring the innermost accretion zone. Future interferometric studies of the Galactic Center Black hole promise to be able to test gravity in its strong field limit.

  20. Cosmological attractors in massive gravity

    CERN Document Server

    Dubovsky, S; Tkachev, I I

    2005-01-01

    We study Lorentz-violating models of massive gravity which preserve rotations and are invariant under time-dependent shifts of the spatial coordinates. In the linear approximation the Newtonian potential in these models has an extra ``confining'' term proportional to the distance from the source. We argue that during cosmological expansion the Universe may be driven to an attractor point with larger symmetry which includes particular simultaneous dilatations of time and space coordinates. The confining term in the potential vanishes as one approaches the attractor. In the vicinity of the attractor the extra contribution is present in the Friedmann equation which, in a certain range of parameters, gives rise to the cosmic acceleration.

  1. Compact lanthanum hexaboride hollow cathode.

    Science.gov (United States)

    Goebel, Dan M; Watkins, Ronald M

    2010-08-01

    A compact lanthanum hexaboride hollow cathode has been developed for space applications where size and mass are important and research and industrial applications where access for implementation might be limited. The cathode design features a refractory metal cathode tube that is easily manufactured, mechanically captured orifice and end plates to eliminate expensive e-beam welding, graphite sleeves to provide a diffusion boundary to protect the LaB6 insert from chemical reactions with the refractory metal tube, and several heater designs to provide long life. The compact LaB(6) hollow cathode assembly including emitter, support tube, heater, and keeper electrode is less than 2 cm in diameter and has been fabricated in lengths of 6-15 cm for different applications. The cathode has been operated continuously at discharge currents of 5-60 A in xenon. Slightly larger diameter versions of this design have operated at up to 100 A of discharge current.

  2. Target-local Gromov compactness

    CERN Document Server

    Fish, Joel W

    2009-01-01

    We prove a version of Gromov's compactness theorem for pseudo-holomorphic curves which holds locally in the target symplectic manifold. This result applies to sequences of curves with an unbounded number of free boundary components, and in families of degenerating target manifolds which have unbounded geometry (e.g. no uniform energy threshold). Core elements of the proof regard curves as submanifolds (rather than maps) and then adapt methods from the theory of minimal surfaces.

  3. Multipole structure of compact objects

    CERN Document Server

    Quevedo, Hernando

    2016-01-01

    We analyze the applications of general relativity in relativistic astrophysics in order to solve the problem of describing the geometric and physical properties of the interior and exterior gravitational and electromagnetic fields of compact objects. We focus on the interpretation of exact solutions of Einstein's equations in terms of their multipole moments structure. In view of the lack of physical interior solutions, we propose an alternative approach in which higher multipoles should be taken into account.

  4. Weak compactness of biharmonic maps

    Directory of Open Access Journals (Sweden)

    Shenzhou Zheng

    2012-10-01

    Full Text Available This article shows that if a sequence of weak solutions of a perturbed biharmonic map satisfies $Phi_ko 0$ in $(W^{2,2}^*$ and $u_kightharpoonup u$ weakly in $W^{2,2}$, then $u$ is a biharmonic map. In particular, we show that the space of biharmonic maps is sequentially compact under the weak-$W^{2,2}$ topology.

  5. Compact differences of composition operators

    CERN Document Server

    Heller, Katherine; Weir, Rachel J

    2010-01-01

    When $\\varphi$ and $\\psi$ are linear-fractional self-maps of the unit ball $B_N$ in ${\\mathbb C}^N$, $N\\geq 1$, we show that the difference $C_{\\varphi}-C_{\\psi}$ cannot be non-trivially compact on either the Hardy space $H^2(B_N)$ or any weighted Bergman space $A^2_{\\alpha}(B_N)$. Our arguments emphasize geometrical properties of the inducing maps $\\varphi$ and $\\psi$.

  6. 78 FR 61384 - Meeting of the Compact Council for the National Crime Prevention and Privacy Compact

    Science.gov (United States)

    2013-10-03

    ... Federal Bureau of Investigation Meeting of the Compact Council for the National Crime Prevention and... of this notice is to announce a meeting of the National Crime Prevention and Privacy Compact Council (Council) created by the National Crime Prevention and Privacy Compact Act of 1998 (Compact). Thus far,...

  7. 78 FR 20355 - Meeting of the Compact Council for the National Crime Prevention and Privacy Compact

    Science.gov (United States)

    2013-04-04

    ... Federal Bureau of Investigation Meeting of the Compact Council for the National Crime Prevention and... this notice is to announce a meeting of the National Crime Prevention and Privacy Compact Council (Council) created by the National Crime Prevention and Privacy Compact Act of 1998 (Compact). Thus far,...

  8. 77 FR 60475 - Meeting of the Compact Council for the National Crime Prevention and Privacy Compact

    Science.gov (United States)

    2012-10-03

    ... Federal Bureau of Investigation Meeting of the Compact Council for the National Crime Prevention and... of this notice is to announce a meeting of the National Crime Prevention and Privacy Compact Council (Council) created by the National Crime Prevention and Privacy Compact Act of 1998 (Compact). Thus far,...

  9. 76 FR 20044 - Meeting of the Compact Council for the National Crime Prevention and Privacy Compact

    Science.gov (United States)

    2011-04-11

    ... Federal Bureau of Investigation Meeting of the Compact Council for the National Crime Prevention and... this notice is to announce a meeting of the National Crime Prevention and Privacy Compact Council (Council) created by the National Crime Prevention and Privacy Compact Act of 1998 (Compact). Thus far,...

  10. 75 FR 62568 - Meeting of the Compact Council for the National Crime Prevention and Privacy Compact

    Science.gov (United States)

    2010-10-12

    ... Federal Bureau of Investigation Meeting of the Compact Council for the National Crime Prevention and... this notice is to announce a meeting of the National Crime Prevention and Privacy Compact Council (Council) created by the National Crime Prevention and Privacy Compact Act of 1998 (Compact). Thus far,...

  11. 76 FR 66326 - Meeting of the Compact Council for the National Crime Prevention and Privacy Compact

    Science.gov (United States)

    2011-10-26

    ... Federal Bureau of Investigation Meeting of the Compact Council for the National Crime Prevention and... this notice is to announce a meeting of the National Crime Prevention and Privacy Compact Council (Council) created by the National Crime Prevention and Privacy Compact Act of 1998 (Compact). Thus far,...

  12. 77 FR 20051 - Meeting of the Compact Council for the National Crime Prevention and Privacy Compact

    Science.gov (United States)

    2012-04-03

    ... Federal Bureau of Investigation Meeting of the Compact Council for the National Crime Prevention and... this notice is to announce a meeting of the National Crime Prevention and Privacy Compact Council (Council) created by the National Crime Prevention and Privacy Compact Act of 1998 (Compact). Thus far,...

  13. GT1_cdedes_1: Heating and cooling mechanics in massive star formation

    Science.gov (United States)

    Dedes, C.

    2010-03-01

    Massive stars are important constituents of the interstellar medium (ISM) in our Galaxy and beyond. Their strong feedback processes influence the dynamics, energetics and chemistry of the surrounding interstellar medium both locally and on large scales. An important question to be answered is the one of cooling and heating mechanisms in regions of massive star formation. In the vicinity of massive stars, heating is provided mostly by far-UV (FUV) and infra-red radiation. Cooling is mostly provided by emission in the fine structure lines of CII. There are however other atomic and molecular lines such as OI, CO, OH and H_2O which can become significant coolants in the dense, embedded regions of massive star formation. This early phase when the forming massive star is still deeply embedded in its natal envelope, yet already interacting with, and potentially destroying, its environment through copious amounts of UV radiation, massive outflows and ultra compact HII (UCHII) regions, is an important phase in the star formation process. To understand the heating and cooling balance in this phase, one has to consider the contributions of various radiative and dynamical processes such as the FUV radiation from the young star itself, shocks created by strong stellar winds and the photon dominated regions (PDRs) where the radiation impinges on the molecular material. The tracers of these processes can be observed in the far-infrared, a wavelength range that is now accessible at unprecedented high spectral and spatial resolution with the Herschel Space Observatory. We propose to observe the aformentioned tracers of cooling and heating in the massive star forming region IRAS 12326-6245 to obtain a complete picture of the different processes, the regions they originate from and how they interact. This proposal is for time granted to the HIFI hardware team (PI: Frank Helmich) and to be accounted as part of the Swiss guaranteed time (Lead-Co-I: Arnold O. Benz).

  14. Strings in compact cosmological spaces

    CERN Document Server

    Craps, Ben; Konechny, Anatoly

    2013-01-01

    We confront the problem of giving a fundamental definition to perturbative string theory in spacetimes with totally compact space (taken to be a torus for simplicity, though the nature of the problem is very general) and non-compact time. Due to backreaction induced by the presence of even a single string quantum, the usual formulation of perturbative string theory in a fixed classical background is infrared-divergent at all subleading orders in the string coupling, and needs to be amended. The problem can be seen as a closed string analogue of D0-brane recoil under an impact by closed strings (a situation displaying extremely similar infrared divergences). Inspired by the collective coordinate treatment of the D0-brane recoil, whereby the translational modes of the D0-brane are introduced as explicit dynamical variables in the path integral, we construct a similar formalism for the case of string-induced gravitational backreaction, in which the spatially uniform modes of the background fields on the compact ...

  15. Comminution circuits for compact itabirites

    Directory of Open Access Journals (Sweden)

    Pedro Ferreira Pinto

    Full Text Available Abstract In the beneficiation of compact Itabirites, crushing and grinding account for major operational and capital costs. As such, the study and development of comminution circuits have a fundamental importance for feasibility and optimization of compact Itabirite beneficiation. This work makes a comparison between comminution circuits for compact Itabirites from the Iron Quadrangle. The circuits developed are: a crushing and ball mill circuit (CB, a SAG mill and ball mill circuit (SAB and a single stage SAG mill circuit (SSSAG. For the SAB circuit, the use of pebble crushing is analyzed (SABC. An industrial circuit for 25 million tons of run of mine was developed for each route from tests on a pilot scale (grinding and industrial scale. The energy consumption obtained for grinding in the pilot tests was compared with that reported by Donda and Bond. The SSSAG route had the lowest energy consumption, 11.8kWh/t and the SAB route had the highest energy consumption, 15.8kWh/t. The CB and SABC routes had a similar energy consumption of 14.4 kWh/t and 14.5 kWh/t respectively.

  16. Compact Stellarator Path to DEMO

    Science.gov (United States)

    Lyon, J. F.

    2007-11-01

    Issues for a DEMO reactor are sustaining an ignited/high-Q plasma in steady state, avoiding disruptions and large variations in power flux to the wall, adequate confinement of thermal plasma and alpha-particles, control of a burning plasma, particle and power handling, etc. Compact stellarators have key advantages -- steady-state high-plasma-density operation without external current drive or disruptions, stability without a close conducting wall or active feedback systems, and low recirculating power -- in addition to moderate plasma aspect ratio, good confinement, and high-beta potential. The ARIES-CS study established that compact stellarators can be competitive with tokamaks as reactors. Many of the issues for a compact stellarator DEMO can be answered using results from large tokamaks, ITER D-T experiments and fusion materials, technology and component development programs, in addition to stellarators in operation, under construction or in development. However, a large next-generation stellarator will be needed to address some physics issues: size scaling and confinement at higher parameters, burning plasma issues, and operation with a strongly radiative divertor. Technology issues include simpler coils, structure, and divertor fabrication, and better cost information.

  17. X-ray emission from hot subdwarfs with compact companions

    CERN Document Server

    Mereghetti, Sandro; Esposito, Paolo; Tiengo, Andrea

    2012-01-01

    We review the X-ray observations of hot subdwarf stars. While no X-ray emission has been detected yet from binaries containing B-type subdwarfs, interesting results have been obtained in the case of the two luminous O-type subdwarfs HD 49798 and BD +37 442. Both of them are members of binary systems in which the X-ray luminosity is powered by accretion onto a compact object: a rapidly spinning (13.2 s) and massive (1.28 M_sun) white dwarf in the case of HD 49798 and most likely a neutron star, spinning at 19.2 s, in the case of BD +37 442. Their study can shed light on the poorly known processes taking place during common envelope evolutionary phases and on the properties of wind mass loss from hot subdwarfs.

  18. Influência do pH final na bioquímica e qualidade do músculo Longissimus dorsi de animais Bos taurus indicus machos inteiros

    OpenAIRE

    Clara Lucía Contreras Baron

    2016-01-01

    O pH final (pHf) no músculo post mortem é amplamente utilizado como um indicador potencial de maciez e é um fator importante associado à qualidade de carne. O Brasil é líder mundial nas exportações de carne bovina, porém não são conhecidos os valores de pHf do músculo pós-abate e seu impacto na qualidade da carne de animais machos inteiros Bos taurus indicus. Baseado no exposto, objetivou-se com este trabalho identificar o atual \\"status\\" dos valores de pHf 24 h post mortem apresentados no f...

  19. Relações metionina + cistina: lisina digestíveis para codornas de corte machos em fase de terminação

    OpenAIRE

    2016-01-01

    RESUMO Com o objetivo de estimar as melhores relações metionina + cistina: lisina digestíveis para codornas de corte machos durante os períodos de 22 a 28 e 29 a 35 dias de idade foram desenvolvidos dois experimentos. As aves foram submetidas a uma ração basal deficiente em metionina + cistina digestível, sendo esta suplementada com cinco níveis de DL-Metionina, em substituição ao ácido glutâmico e amido, resultando nas seguintes relações metionina + cistina: lisina digestíveis: 0,68; 0,73; 0...

  20. Fontes e Níveis de Energia Digestível em Rações para Suínos Machos Inteiros dos 60 aos 100 kg

    OpenAIRE

    Mascarenhas Alessandra Gimenez; Donzele Juarez Lopes; Oliveira Rita Flávia Miranda de; Ferreira Aloízio Soares; Lopes Rogério dos Santos; Tavares Sandra Lúcia

    2002-01-01

    Visando avaliar o efeito de duas fontes lipídicas (óleo de soja e gordura de coco) e de quatro níveis de energia digestível (3350, 3450, 3550 e 3650 kcal/kg de ração) sobre o desempenho de suínos machos inteiros, dos 60 aos 100 kg, foram utilizados oitenta animais, distribuídos num arranjo fatorial 2 x 4 (fontes x níveis de energia), em delineamento de blocos ao acaso, com cinco repetições de dois animais por baia. As rações experimentais, formuladas à base de milho, farelo de soja e suplemen...

  1. Propuesta de una ecuación lineal para valorar la velocidad de crecimiento somático a partir de la masa corporal de ratas machos Wistar

    Directory of Open Access Journals (Sweden)

    Marco Antonio Cossio-Bolanos

    2012-04-01

    Full Text Available Introducción: Para conocer el grado de maduración biológica de los roedores es necesaria la aplicación de métodos invasivos y no-invasivos, para lo cual los estudios que engloban diversas cepas de ratas necesitan de procedimientos simples de manera de controlar los efectos de confusión que la maduración biológica pudiera ocasionar. Objetivos: Determinar la velocidad de crecimiento (VC de ratas machos Wistar a partir de la masa corporal y proponer ecuaciones de regresión lineal para predecir el pico de velocidad de crecimiento (PVC. Diseño: Estudio longitudinal de cohorte. Institución: Universidad Estadual de Campinas, São Paulo, Brasil, Departamento de Farmacología. Métodos: De un total de 101 ratas, se seleccionó de forma probabilística-aleatoria (tablas aleatorias 25 ratas machos Wistar de 3 semanas de vida (21 días de edad. Se evaluó la masa corporal (g cada semana, hasta las 16 semanas de vida. Para el análisis estadístico se utilizó la estadística descriptiva de la media aritmética (X y desviación estándar (DE. Para determinar las diferencias significativas entre las edades se usó ANOVA para medidas repetitivas (p<0,001 y para correlacionar las variables de edad, peso y PVC se utilizó (r de Pearson (p<0,001. La predicción del PVC se efectuó a través del análisis de regresión lineal simple y múltiple StepWise (p<0,001. Principales medidas de resultados: Velocidad de crecimiento; propuesta de ecuaciones de regresión lineal para predecir el pico de velocidad de crecimiento. Resultados: Los resultados muestran que la velocidad de crecimiento evaluada a través de la masa corporal se presentó alrededor de los 42 días de vida. Con dichos resultados se generó tres ecuaciones de regresión lineal simple y múltiple, donde el coeficiente de determinación (R² para el modelo 1 fue 0,99, para el modelo 2, 0,89 y para el modelo 3, 0,99, respectivamente. Estas ecuaciones permiten predecir la proximidad y el

  2. Motion Analysis of Fiber Band in Compact Field of Compact Spinning

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The technological process of compact spinning and the compact procedure of fiber band in compact field are briefly illustrated. The motions of fiber band in compact field are discussed theoretically from which tilting angle of suction slot in profile tube, additional twists created by fiber band's rotating around its own axis and ultimate twists in compact yarn are deduced accordingly. The existence of additional twists is also verified through experiments.

  3. Influencia de la madurez sexual y la castración sobre la actividad eléctrica cardíaca en conejos machos y hembras

    Directory of Open Access Journals (Sweden)

    Gabriela Y. Eizikovits

    2010-08-01

    Full Text Available Es bien conocida la existencia de diferencias en la actividad eléctrica cardíaca asociadas al sexo. Si bien estas diferencias habitualmente se relacionan al efecto de la madurez y de las hormonas sexuales gonadales, todavía existen controversias al respecto. El objetivo de este trabajo fue evaluar el efecto que la madurez sexual y la castración producen sobre los distintos parámetros del electrocardiograma de superficie y de la duración de los potenciales de acción (DPA. Se utilizaron conejos jóvenes (menores de un mes de edad y adultos (mayores de seis meses de edad. Las diferencias obtenidas en las hembras se observan en la repolarización tardía, mientras que en los machos ocurren en la repolarización temprana. Existiría una relación entre las diferencias observadas en la duración desde el pico máximo hasta el fin de la onda T (Tpf y las observadas en la DPA al 90% de la repolarización (DPA90 en las hembras, mientras que en los machos la relación existe entre la duración desde el punto J hasta el pico máximo de la onda T (JTp y la DPA al 30 y 50% de la repolarización (DPA30 y DPA50. Si bien existen diferencias que podrían ser debidas a factores hormonales otras serían debidas a factores no hormonales.

  4. How I treat patients with massive hemorrhage

    DEFF Research Database (Denmark)

    Johansson, Pär I; Stensballe, Jakob; Oliveri, Roberto

    2014-01-01

    Massive hemorrhage is associated with coagulopathy and high mortality. The transfusion guidelines up to 2006 recommended that resuscitation of massive hemorrhage should occur in successive steps using crystalloids, colloids and red blood cells (RBC) in the early phase, and plasma and platelets in...

  5. Stefan-Boltzmann law for massive photons

    CERN Document Server

    Moreira, E S

    2015-01-01

    Thirty years ago a paper appeared in the literature generalizing the Stefan-Boltzmann law to include massive photons. The paper suffers from a flaw though: it assumes that a massive photon travels at the speed of (massless) light. The present work fixes the mistake and presents the correct formula for the radiance.

  6. Stefan-Boltzmann Law for Massive Photons

    Science.gov (United States)

    Moreira, E. S.; Ribeiro, T. G.

    2016-08-01

    This paper generalizes the Stefan-Boltzmann law to include massive photons. A crucial ingredient to obtain the correct formula for the radiance is to realize that a massive photon does not travel at the speed of (massless) light. It follows that, contrary to what could be expected, the radiance is not proportional to the energy density times the speed of light.

  7. Mass Loss and Evolution of Massive Stars

    NARCIS (Netherlands)

    Lamers, H.J.G.L.M.

    2013-01-01

    I discuss the early observations and the discovery of stellar winds from massive stars, including the development of wind theories, the effects of mass loss on stellar evolution, the role of rotation and the evolutionary connection between different types of massive stars. Because of the special

  8. The massive Kaluza-Klein monopole

    NARCIS (Netherlands)

    Bergshoeff, E; Eyras, E; Lozano, Y

    1998-01-01

    We construct the (bosonic) effective worldvolume action of an M-theory Kaluza-Klein monopole in a background given by the bosonic sector of eleven-dimensional massive supergravity, i.e, a "massive Kaluza-Klein monopole". As a consistency check we show that the direct dimensional reduction along the

  9. 10 billion years of massive Galaxies

    NARCIS (Netherlands)

    Taylor, Edward Nairne Cunningham

    2009-01-01

    The most massive galaxies in the local universe are not forming new stars -- but we don’t know why. As a step towards figuring out why big galaxies stop forming stars, we set out to measure when they stop forming stars. By looking at the colors of massive galaxies have changed over 10 billion year

  10. On the singularities of massive superstring amplitudes

    NARCIS (Netherlands)

    Foda, O.

    1987-01-01

    Superstring one-loop amplitudes with massive external states are shown to be in general ill-defined due to internal on-shell propagators. However, we argue that since any massive string state (in the uncompactified theory) has a finite lifetime to decay into massless particles, such amplitudes are n

  11. On the singularities of massive superstring amplitudes

    NARCIS (Netherlands)

    Foda, O.

    1987-01-01

    Superstring one-loop amplitudes with massive external states are shown to be in general ill-defined due to internal on-shell propagators. However, we argue that since any massive string state (in the uncompactified theory) has a finite lifetime to decay into massless particles, such amplitudes are

  12. XFEM for Thermal Crack of Massive Concrete

    Directory of Open Access Journals (Sweden)

    Guowei Liu

    2013-01-01

    Full Text Available Thermal cracking of massive concrete structures occurs as a result of stresses caused by hydration in real environment conditions. The extended finite element method that combines thermal fields and creep is used in this study to analyze the thermal cracking of massive concrete structures. The temperature field is accurately simulated through an equivalent equation of heat conduction that considers the effect of a cooling pipe system. The time-dependent creep behavior of massive concrete is determined by the viscoelastic constitutive model with Prony series. Based on the degree of hydration, we consider the main properties related to cracking evolving with time. Numerical simulations of a real massive concrete structure are conducted. Results show that the developed method is efficient for numerical calculations of thermal cracks on massive concrete. Further analyses indicate that a cooling system and appropriate heat preservation measures can efficiently prevent the occurrence of thermal cracks.

  13. Massive Star Formation: The Power of Interferometry

    CERN Document Server

    Beuther, Henrik

    2007-01-01

    This article presents recent work to constrain the physical and chemical properties in high-mass star formation based largely on interferometric high-spatial-resolution continuum and spectral line studies at (sub)mm wavelengths. After outlining the concepts, potential observational tests, a proposed evolutionary sequence and different possible definitions for massive protostars, four particular topics are highlighted: (a) What are the physical conditions at the onset of massive star formation? (b) What are the characteristics of potential massive accretion disks and what do they tell us about massive star formation in general? (c) How do massive clumps fragment, and what does it imply to high-mass star formation? (d) What do we learn from imaging spectral line surveys with respect to the chemistry itself as well as for utilizing molecules as tools for astrophysical investigations?

  14. Massive MIMO Wireless Networks: An Overview

    Directory of Open Access Journals (Sweden)

    Noha Hassan

    2017-09-01

    Full Text Available Massive multiple-input-multiple-output (MIMO systems use few hundred antennas to simultaneously serve large number of wireless broadband terminals. It has been incorporated into standards like long term evolution (LTE and IEEE802.11 (Wi-Fi. Basically, the more the antennas, the better shall be the performance. Massive MIMO systems envision accurate beamforming and decoding with simpler and possibly linear algorithms. However, efficient signal processing techniques have to be used at both ends to overcome the signaling overhead complexity. There are few fundamental issues about massive MIMO networks that need to be better understood before their successful deployment. In this paper, we present a detailed review of massive MIMO homogeneous, and heterogeneous systems, highlighting key system components, pros, cons, and research directions. In addition, we emphasize the advantage of employing millimeter wave (mmWave frequency in the beamforming, and precoding operations in single, and multi-tier massive MIMO systems.

  15. Too large and overlooked? Extended free-free emission towards massive star formation regions

    CERN Document Server

    Longmore, S N; Keto, E; Kurtz, S; Walsh, A J

    2009-01-01

    We present Australia Telescope Compact Array observations towards 6 massive star formation regions which, from their strong 24 GHz continuum emission but no compact 8 GHz continuum emission, appeared good candidates for hyper-compact HII regions. However, the properties of the ionised gas derived from the 19 to 93 GHz continuum emission and H70 alpha + H57 alpha radio recombination line data show the majority of these sources are, in fact, regions of spatially-extended, optically-thin free-free emission. These extended sources were missed in the previous 8 GHz observations due to a combination of spatial-filtering, poor surface brightness sensitivity and primary beam attenuation. We consider the implications that a significant number of these extended HII regions may have been missed by previous surveys of massive star formation regions. If the original sample of 21 sources is representative of the population as a whole, the fact that 6 contain previously undetected extended free-free emission suggests a larg...

  16. Der Global Compact und der Schutz der Menschenrechte

    OpenAIRE

    Hamm, Brigitte I.

    2011-01-01

    Inhalt: - I. Einleitung - II. Was ist der Global Compact? - III. Wie funktioniert der Global Compact? - IV. Der Global Compact will kein Verhaltenskodex sein. - V. Der Global Compact als Bestandteil von „global governance“ - VI. Der Global Compact und der Schutz der Menschenrechte - VII. Ausschau - Literatur - Teilnehmer des Global Compact

  17. A massively asynchronous, parallel brain

    Science.gov (United States)

    Zeki, Semir

    2015-01-01

    Whether the visual brain uses a parallel or a serial, hierarchical, strategy to process visual signals, the end result appears to be that different attributes of the visual scene are perceived asynchronously—with colour leading form (orientation) by 40 ms and direction of motion by about 80 ms. Whatever the neural root of this asynchrony, it creates a problem that has not been properly addressed, namely how visual attributes that are perceived asynchronously over brief time windows after stimulus onset are bound together in the longer term to give us a unified experience of the visual world, in which all attributes are apparently seen in perfect registration. In this review, I suggest that there is no central neural clock in the (visual) brain that synchronizes the activity of different processing systems. More likely, activity in each of the parallel processing-perceptual systems of the visual brain is reset independently, making of the brain a massively asynchronous organ, just like the new generation of more efficient computers promise to be. Given the asynchronous operations of the brain, it is likely that the results of activities in the different processing-perceptual systems are not bound by physiological interactions between cells in the specialized visual areas, but post-perceptually, outside the visual brain. PMID:25823871

  18. Origin of ultra-compact dwarfs: a dynamical perspective

    Science.gov (United States)

    Zhang, Hong-Xin; Peng, Eric W.; Côté, Patrick; Liu, Chengze; Ferrarese, Laura; Cuillandre, Jean-Charles; Caldwell, Nelson; Gwyn, Stephen D. J.; Jordán, Andrés; Lançon, Ariane; Li, Biao; Muñoz, Roberto P.; Puzia, Thomas H.; Bekki, Kenji; Blakeslee, John; Boselli, Alessandro; Drinkwater, Michael J.; Duc, Pierre-Alain; Durrell, Patrick; Emsellem, Eric; Firth, Peter; Sánchez-Janssen, Ruben

    2016-02-01

    Discovery of ultra-compact dwarfs (UCDs) in the past 15 years blurs the once thought clear division between classic globular clusters (GCs) and early-type galaxies. The intermediate nature of UCDs, which are larger and more massive than typical GCs but more compact than typical dwarf galaxies, has triggered hot debate on whether UCDs should be considered galactic in origin or merely the most extreme GCs. Previous studies of various scaling relations, stellar populations and internal dynamics did not give an unambiguous answer to the primary origin of UCDs. In this contribution, we present the first ever detailed study of global dynamics of 97 UCDs (r h >~ 10 pc) associated with the central cD galaxy of the Virgo cluster, M87. We found that UCDs follow a different radial number density profile and different rotational properties from GCs. The orbital anisotropies of UCDs are tangentially-biased within ~ 40 kpc of M87 and become radially-biased with radius further out. In contrast, the blue GCs, which have similar median colors to our sample of UCDs, become more tangentially-biased at larger radii beyond ~ 40 kpc. Our analysis suggests that most UCDs in M87 are not consistent with being merely the most luminous and extended examples of otherwise normal GCs. The radially-biased orbital structure of UCDs at large radii is in general agreement with the scenario that most UCDs originated from the tidally threshed dwarf galaxies.

  19. Self-compacting concrete (SCC)

    DEFF Research Database (Denmark)

    Geiker, Mette Rica

    2008-01-01

    In many aspects Self-Compacting Concrete (SCC, “Self-Consolidating Concrete” in North America) can be considered the concrete of the future. SCC is a family of tailored concretes with special engineered properties in the fresh state. SCC flows into the formwork and around even complicated...... reinforcement arrangements under its own weight. Thus, SCC is not vibrated like conventional concrete. This drastically improves the working environment during construction, the productivity, and potentially improves the homogeneity and quality of the concrete. In addition SCC provides larger architectural...

  20. Porewater chemistry in compacted bentonite

    Energy Technology Data Exchange (ETDEWEB)

    Muurinen, A.; Lehikoinen, J. [VTT Chemical Technology, Espoo (Finland)

    1999-03-01

    In this study, the porewater chemistry in compacted bentonite, considered as an engineered barrier in the repository of spent fuel, has been studied in interaction experiments. Many parameters, like the composition and density of bentonite, composition of the solution, bentonite-to-water ratio (B/W), surrounding conditions and experimental time have been varied in the experiments. At the end of the interaction the equilibrating solution, the porewaters squeezed out of the bentonite samples, and bentonites themselves were analyzed to give information for the interpretation and modelling of the interaction. Equilibrium modelling was performed with the HYDRAQL/CE computer code 33 refs.

  1. Compact Radiometers Expand Climate Knowledge

    Science.gov (United States)

    2010-01-01

    To gain a better understanding of Earth's water, energy, and carbon cycles, NASA plans to embark on the Soil Moisture Active and Passive mission in 2015. To prepare, Goddard Space Flight Center provided Small Business Innovation Research (SBIR) funding to ProSensing Inc., of Amherst, Massachusetts, to develop a compact ultrastable radiometer for sea surface salinity and soil moisture mapping. ProSensing incorporated small, low-cost, high-performance elements into just a few circuit boards and now offers two lightweight radiometers commercially. Government research agencies, university research groups, and large corporations around the world are using the devices for mapping soil moisture, ocean salinity, and wind speed.

  2. Compact Hermitian Young Projection Operators

    CERN Document Server

    Alcock-Zeilinger, Judith

    2016-01-01

    In this paper, we describe a compact and practical algorithm to construct Hermitian Young projection operators for irreducible representations of the special unitary group SU(N), and discuss why ordinary Young projection operators are unsuitable for physics applications. The proof of this construction algorithm uses the iterative method described by Keppeler and Sj\\"odahl. We further show that Hermitian Young projection operators share desirable properties with Young tableaux, namely a nested hierarchy when "adding a particle". We end by exhibiting the enormous advantage of the Hermitian Young projection operators constructed in this paper over those given by Keppeler and Sj\\"odahl.

  3. Compact objects in Horndeski gravity

    CERN Document Server

    Silva, Hector O; Minamitsuji, Masato; Berti, Emanuele

    2016-01-01

    Horndeski gravity holds a special position as the most general extension of Einstein's theory of general relativity with a single scalar degree of freedom and second-order field equations. Because of these features, Horndeski gravity is an attractive phenomenological playground to investigate the consequences of modifications of general relativity in cosmology and astrophysics. We present a review of the progress made so far in the study of compact objects (black holes and neutron stars) within Horndeski gravity. In particular, we review our recent work on slowly rotating black holes and present some new results on slowly rotating neutron stars.

  4. Discovery of Compact Quiescent Galaxies at Intermediate Redshifts in DEEP2

    Science.gov (United States)

    Blancato, Kirsten; Chilingarian, Igor; Damjanov, Ivana; Moran, Sean; Katkov, Ivan

    2015-01-01

    Compact quiescent galaxies in the redshift range 0.6 histories of these objects from the high redshift z ≥ 2 Universe to the local z ~ 0 Universe. We identify the first intermediate redshift compact quiescent galaxies by searching a sample of 1,089 objects in the DEEP2 Redshift Survey that have multi-band photometry, spectral fitting, and readily available structural parameters. We find 27 compact quiescent candidates between z = 0.6 and z = 1.1 where each candidate galaxy has archival Hubble Space Telescope (HST) imaging and is visually confirmed to be early-type. The candidates have half-light radii ranging from 0.83 2 which suggests these objects may be the relics of the observed high redshift compact galaxies and formation at z ≤ 2 which suggests there is an additional population of more recently formed massive compact galaxies. This work is supported in part by the NSF REU and DOD ASSURE programs under NSF grant no. 1262851 and by the Smithsonian Institution.

  5. Compaction and Quenching of High-z Galaxies: Blue and Red Nuggets in Cosmological Simulations

    CERN Document Server

    Zolotov, Adi; Mandelker, Nir; Tweed, Dylan; Inoue, Shigeki; DeGraf, Colin; Ceverino, Daniel; Primack, Joel

    2014-01-01

    We use cosmological simulations to study a characteristic evolution pattern of high redshift galaxies. Early, stream-fed, highly perturbed, gas-rich discs undergo phases of dissipative contraction into compact, star-forming systems (blue nuggets) at z~4-2. The peak of gas compaction marks the onset of central gas depletion and inside-out quenching into compact ellipticals (red nuggets) by z~2. These are sometimes surrounded by gas rings or grow extended dry stellar envelopes. The compaction occurs at a roughly constant specific star-formation rate (SFR), and the quenching occurs at a constant stellar surface density within the inner kpc (Sigma_1). Massive galaxies quench earlier, faster, and at a higher Sigma_1 than lower-mass galaxies, which compactify and attempt to quench more than once. This evolution pattern is consistent with the way galaxies populate the SFR-radius-mass space, and with gradients and scatter across the main sequence. The compaction is triggered by an intense inflow episode, involving me...

  6. Turmoil in Orion: The Nearest Massive Protostar

    CERN Document Server

    Tan, Jonathan C

    2008-01-01

    I discuss different theories of massive star formation: formation from massive cores, competitive Bondi-Hoyle accretion, and protostellar collisions. I summarize basic features of the Turbulent Core Model (TCM). I then introduce the Orion Kleinmann-Low (KL) region, embedded in the Orion Nebula Cluster (ONC) and one of the nearest regions of massive star formation. The KL region contains three principal radio sources, known as "I", "n" and "BN". BN is known to be a runaway star, almost certainly set in motion by dynamical ejection within the ONC from a multiple system of massive stars, that would leave behind a recoiling, hard, massive, probably eccentric binary. I review the debate about whether this binary is Theta^1C, the most massive star in the ONC, or source "I", and argue that it is most likely to be Theta^1C, since this is now known be a recoiling, hard, massive, eccentric binary, with properties that satisfy the energy and momentum constraints implied by BN's motion. Source "n" is a relatively low-mas...

  7. Machos e Brothers: uma etnografia sobre o armário em relações homoeróticas masculinas criadas on-line Machos and brothers: an ethnography about the closet in male homoerotic relations created on-line

    Directory of Open Access Journals (Sweden)

    Richard Miskolci

    2013-04-01

    Full Text Available A partir de uma etnografia feita com homens que se apresentam como Macho ou Brother em salas de bate-papo dirigidas a um público gay e bissexual da cidade de São Paulo, este artigo explora como eles articulam plataformas de busca de parceiros com o objetivo de criar relações em segredo. Esses homens apresentam-se e buscam parceiros que se descrevem como "discretos" e "fora do meio gay", forjando relações dentro do regime de controle da sexualidade conhecido como armário. Busco expor e compreender as normas de sexualidade e gênero que regem o armário desses usuários, os quais buscam manter seu status heterossexual mesmo tendo relações amorosas e/ou sexuais com outros homens.Based on an ethnography with men who introduce themselves as Macho or Brother in chatrooms directed toward a gay and bisexual audience in the city of São Paulo, this article explores how these users articulate different platforms to create secret relationships. These men introduce themselves and search for partners that can be described as "straight acting" and "not part of the gay scene" creating relations shaped by the sexuality control regime known as the closet. This analysis tries to expose gender and sexuality norms that shape these users' closet, or the way they act trying to keep their heterosexual status while also having sexual or love relationship with other men.

  8. A compact THz imaging system

    Science.gov (United States)

    Sešek, Aleksander; Å vigelj, Andrej; Trontelj, Janez

    2015-03-01

    The objective of this paper is the development of a compact low cost imaging THz system, usable for observation of the objects near to the system and also for stand-off detection. The performance of the system remains at the high standard of more expensive and bulkiest system on the market. It is easy to operate as it is not dependent on any fine mechanical adjustments. As it is compact and it consumes low power, also a portable system was developed for stand-off detection of concealed objects under textile or inside packages. These requirements rule out all optical systems like Time Domain Spectroscopy systems which need fine optical component positioning and requires a large amount of time to perform a scan and the image capture pixel-by-pixel. They are also almost not suitable for stand-off detection due to low output power. In the paper the antenna - bolometer sensor microstructure is presented and the THz system described. Analysis and design guidelines for the bolometer itself are discussed. The measurement results for both near and stand-off THz imaging are also presented.

  9. Compact sources for eyesafe illumination

    Science.gov (United States)

    Baranova, N.; Pu, R.; Stebbins, K.; Bystryak, I.; Rayno, M.; Ezzo, K.; DePriest, C.

    2017-02-01

    Q-Peak has demonstrated a novel, compact, pulsed eyesafe laser architecture operating with <10 mJ pulse energies at repetition rates as high as 160 Hz. The design leverages an end-pumped solid-state laser geometry to produce adequate eyesafe beam quality (M2 4), while also providing a path towards higher-density laser architectures for pulsed eyesafe applications. The baseline discussed in this paper has shown a unique capability for high pulse repetition rates in a compact package, and offers additional potential for power scaling based on birefringence compensation. The laser consists of an actively Q-switched oscillator cavity producing pulse-widths <30 ns, and utilizing an end-pumped Nd: YAG gain medium with a Rubidium Titanyl Phosphate (RTP) electro-optical crystal. The oscillator provides an effective front-end-seed for an optical parametric oscillator (OPO), which utilizes Potassium Titanyl Arsenate (KTA) in a linear OPO geometry. This laser efficiently operates in the eyesafe band, and has been designed to fit within a volume of 3760 cm3. We will discuss details of the optical system design, modeled thermal effects and stress-induced birefringence, as well as experimental advantages of the end-pumped laser geometry, along with proposed paths to higher eyesafe pulse energies.

  10. Compact Microscope Imaging System Developed

    Science.gov (United States)

    McDowell, Mark

    2001-01-01

    The Compact Microscope Imaging System (CMIS) is a diagnostic tool with intelligent controls for use in space, industrial, medical, and security applications. The CMIS can be used in situ with a minimum amount of user intervention. This system, which was developed at the NASA Glenn Research Center, can scan, find areas of interest, focus, and acquire images automatically. Large numbers of multiple cell experiments require microscopy for in situ observations; this is only feasible with compact microscope systems. CMIS is a miniature machine vision system that combines intelligent image processing with remote control capabilities. The software also has a user-friendly interface that can be used independently of the hardware for post-experiment analysis. CMIS has potential commercial uses in the automated online inspection of precision parts, medical imaging, security industry (examination of currency in automated teller machines and fingerprint identification in secure entry locks), environmental industry (automated examination of soil/water samples), biomedical field (automated blood/cell analysis), and microscopy community. CMIS will improve research in several ways: It will expand the capabilities of MSD experiments utilizing microscope technology. It may be used in lunar and Martian experiments (Rover Robot). Because of its reduced size, it will enable experiments that were not feasible previously. It may be incorporated into existing shuttle orbiter and space station experiments, including glove-box-sized experiments as well as ground-based experiments.

  11. Geotechnical Aspects of Explosive Compaction

    Directory of Open Access Journals (Sweden)

    Mahdi Shakeran

    2016-01-01

    Full Text Available Explosive Compaction (EC is the ground modification technique whereby the energy released from setting off explosives in subsoil inducing artificial earthquake effects, which compact the soil layers. The efficiency of EC predominantly depends on the soil profile, grain size distribution, initial status, and the intensity of energy applied to the soil. In this paper, in order to investigate the geotechnical aspects, which play an important role in performance of EC, a database has been compiled from thirteen-field tests or construction sites around the world, where EC has been successfully applied for modifying soil. This research focuses on evaluation of grain size distribution and initial stability status of deposits besides changes of soil penetration resistance due to EC. Results indicated suitable EC performance for unstable and liquefiable deposits having particle sizes ranging from gravel to silty sand with less than 40% silt content and less than 10% clay content. However, EC is most effective in fine-to-medium sands with a fine content less than 5% and hydraulically deposited with initial relative density ranging from 30% to 60%. Moreover, it has been observed that EC can be an effective method to improve the density, stability, and resistance of the target soils.

  12. Compact Visualisation of Video Summaries

    Directory of Open Access Journals (Sweden)

    Ćalić Janko

    2007-01-01

    Full Text Available This paper presents a system for compact and intuitive video summarisation aimed at both high-end professional production environments and small-screen portable devices. To represent large amounts of information in the form of a video key-frame summary, this paper studies the narrative grammar of comics, and using its universal and intuitive rules, lays out visual summaries in an efficient and user-centered way. In addition, the system exploits visual attention modelling and rapid serial visual presentation to generate highly compact summaries on mobile devices. A robust real-time algorithm for key-frame extraction is presented. The system ranks importance of key-frame sizes in the final layout by balancing the dominant visual representability and discovery of unanticipated content utilising a specific cost function and an unsupervised robust spectral clustering technique. A final layout is created using an optimisation algorithm based on dynamic programming. Algorithm efficiency and robustness are demonstrated by comparing the results with a manually labelled ground truth and with optimal panelling solutions.

  13. Using massive digital libraries a LITA guide

    CERN Document Server

    Weiss, Andrew

    2014-01-01

    Some have viewed the ascendance of the digital library as some kind of existential apocalypse, nothing less than the beginning of the end for the traditional library. But Weiss, recognizing the concept of the library as a ""big idea"" that has been implemented in many ways over thousands of years, is not so gloomy. In this thought-provoking and unabashedly optimistic book, he explores how massive digital libraries are already adapting to society's needs, and looks ahead to the massive digital libraries of tomorrow, coveringThe author's criteria for defining massive digital librariesA history o

  14. Geometric massive higher spins and current exchanges

    CERN Document Server

    Francia, Dario

    2008-01-01

    Generalised Fierz-Pauli mass terms allow to describe massive higher-spin fields on flat background by means of simple quadratic deformations of the corresponding geometric, massless Lagrangians. In this framework there is no need for auxiliary fields. We briefly review the construction in the bosonic case and study the interaction of these massive fields with external sources, computing the corresponding propagators. In the same fashion as for the massive graviton, but differently from theories where auxiliary fields are present, the structure of the current exchange is completely determined by the form of the mass term itself.

  15. Massive Star Formation: Accreting from Companion

    Indian Academy of Sciences (India)

    X. Chen; J. S. Zhang

    2014-09-01

    We report the possible accretion from companion in the massive star forming region (G350.69–0.49). This region seems to be a binary system composed of a diffuse object (possible nebulae or UC HII region) and a Massive Young Stellar Object (MYSO) seen in Spitzer IRAC image. The diffuse object and MYSO are connected by the shock-excited 4.5 m emission, suggesting that the massive star may form through accreting material from the companion in this system.

  16. Morganella morganii sepsis with massive hemolysis.

    Science.gov (United States)

    Kim, Jong Hoon; Cho, Chong Rae; Um, Tae Hyun; Rhu, Ji Yoon; Kim, Eu Suk; Jeong, Jae Won; Lee, Hye Ran

    2007-12-01

    Morganella morganii is a facultative gram-negative and anaerobic rod. It may be a cause of devastating infections in neonates and immunocompromised hosts. Some bacterial infections such as Clostridium and Vibrio are associated with hemolysis. However, massive hemolysis caused by M. morganii sepsis has not yet been reported. We observed a 59-yr-old man who had chemotherapy-induced neutropenia and was found to have massive hemolysis and metabolic acidosis due to sepsis. He died 6 hr after admission in spite of aggressive treatment. Two sets of blood cultures revealed the growth of M. morganii. We report here that M. morganii sepsis can cause fatal massive hemolysis leading to death.

  17. Brittle and compaction creep in porous sandstone

    Science.gov (United States)

    Heap, Michael; Brantut, Nicolas; Baud, Patrick; Meredith, Philip

    2015-04-01

    Strain localisation in the Earth's crust occurs at all scales, from the fracture of grains at the microscale to crustal-scale faulting. Over the last fifty years, laboratory rock deformation studies have exposed the variety of deformation mechanisms and failure modes of rock. Broadly speaking, rock failure can be described as either dilatant (brittle) or compactive. While dilatant failure in porous sandstones is manifest as shear fracturing, their failure in the compactant regime can be characterised by either distributed cataclastic flow or the formation of localised compaction bands. To better understand the time-dependency of strain localisation (shear fracturing and compaction band growth), we performed triaxial deformation experiments on water-saturated Bleurswiller sandstone (porosity = 24%) under a constant stress (creep) in the dilatant and compactive regimes, with particular focus on time-dependent compaction band formation in the compactive regime. Our experiments show that inelastic strain accumulates at a constant stress in the brittle and compactive regimes leading to the development of shear fractures and compaction bands, respectively. While creep in the dilatant regime is characterised by an increase in porosity and, ultimately, an acceleration in axial strain to shear failure (as observed in previous studies), compaction creep is characterised by a reduction in porosity and a gradual deceleration in axial strain. The overall deceleration in axial strain, AE activity, and porosity change during creep compaction is punctuated by excursions interpreted as the formation of compaction bands. The growth rate of compaction bands formed during creep is lower as the applied differential stress, and hence background creep strain rate, is decreased, although the inelastic strain required for a compaction band remains constant over strain rates spanning several orders of magnitude. We find that, despite the large differences in strain rate and growth rate

  18. Massive Black Hole Binary Evolution

    Directory of Open Access Journals (Sweden)

    Merritt David

    2005-11-01

    Full Text Available Coalescence of binary supermassive black holes (SBHs would constitute the strongest sources of gravitational waves to be observed by LISA. While the formation of binary SBHs during galaxy mergers is almost inevitable, coalescence requires that the separation between binary components first drop by a few orders of magnitude, due presumably to interaction of the binary with stars and gas in a galactic nucleus. This article reviews the observational evidence for binary SBHs and discusses how they would evolve. No completely convincing case of a bound, binary SBH has yet been found, although a handful of systems (e.g. interacting galaxies; remnants of galaxy mergers are now believed to contain two SBHs at projected separations of <~ 1kpc. N-body studies of binary evolution in gas-free galaxies have reached large enough particle numbers to reproduce the slow, “diffusive” refilling of the binary’s loss cone that is believed to characterize binary evolution in real galactic nuclei. While some of the results of these simulations - e.g. the binary hardening rate and eccentricity evolution - are strongly N-dependent, others - e.g. the “damage” inflicted by the binary on the nucleus - are not. Luminous early-type galaxies often exhibit depleted cores with masses of ~ 1-2 times the mass of their nuclear SBHs, consistent with the predictions of the binary model. Studies of the interaction of massive binaries with gas are still in their infancy, although much progress is expected in the near future. Binary coalescence has a large influence on the spins of SBHs, even for mass ratios as extreme as 10:1, and evidence of spin-flips may have been observed.

  19. Detection of Prominent Stellar Disks in the Progenitors of Present-day Massive Elliptical Galaxies

    Science.gov (United States)

    Davari, Roozbeh H.; Ho, Luis C.; Mobasher, Bahram; Canalizo, Gabriela

    2017-02-01

    Massive galaxies at high redshifts (z > 2) show different characteristics from their local counterparts: they are compact and most likely have a disk. In this study, we trace the evolution of local massive galaxies by performing a detailed morphological analysis, namely, fitting single Sérsic profiles and performing bulge+disk decompositions. We analyze ∼250 massive galaxies selected from all CANDELS fields (COSMOS, UDS, EGS, GOODS-South, and GOODS-North). We confirm that both star-forming and quiescent galaxies increase their sizes significantly from z ≈ 2.5 to the present day. The global Sérsic index of quiescent galaxies increases over time (from n ≈ 2.5 to n > 4), while that of star-forming galaxies remains roughly constant (n ≈ 2.5). By decomposing galaxy profiles into bulge+disk components, we find that massive galaxies at high redshift have prominent stellar disks, which are also evident from visual inspection of the images. By z ≈ 0.5, the majority of the disks disappear and massive quiescent galaxies begin to resemble the local elliptical galaxies. Star-forming galaxies have lower bulge-to-total ratios (B/T) than their quiescent counterparts in each redshift bin. The bulges of star-forming and quiescent galaxies follow different evolutionary histories, while their disks evolve similarly. Based on our morphological analysis and previous cosmological simulations, we argue that major mergers, along with minor mergers, have played a crucial role in the significant increase in size of high-z galaxies and the destruction of their massive and large-scale disks.

  20. Towards a census of supercompact massive galaxies in the Kilo Degree Survey

    Science.gov (United States)

    Tortora, C.; La Barbera, F.; Napolitano, N. R.; Roy, N.; Radovich, M.; Cavuoti, S.; Brescia, M.; Longo, G.; Getman, F.; Capaccioli, M.; Grado, A.; Kuijken, K. H.; de Jong, J. T. A.; McFarland, J. P.; Puddu, E.

    2016-04-01

    The abundance of compact, massive, early-type galaxies (ETGs) provides important constraints to galaxy formation scenarios. Thanks to the area covered, depth, excellent spatial resolution and seeing, the ESO Public optical Kilo Degree Survey (KiDS), carried out with the VLT Survey Telescope, offers a unique opportunity to conduct a complete census of the most compact galaxies in the Universe. This paper presents a first census of such systems from the first 156 deg2 of KiDS. Our analysis relies on g-, r- and i-band effective radii (Re), derived by fitting galaxy images with point spread function (PSF)-convolved Sérsic models, high-quality photometric redshifts, zphot, estimated from machine learning techniques, and stellar masses, M⋆, calculated from KiDS aperture photometry. After massiveness ({M_{⋆}}≳ 8 × 10^{10} M_{⊙}) and compactness ({R_e}≲ 1.5 kpc in g, r and i bands) criteria are applied, a visual inspection of the candidates plus near-infrared photometry from VIKING-DR1 are used to refine our sample. The final catalogue, to be spectroscopically confirmed, consists of 92 systems in the redshift range z ˜ 0.2-0.7. This sample, which we expect to increase by a factor of 10 over the total survey area, represents the first attempt to select massive supercompact ETGs (MSCGs) in KiDS. We investigate the impact of redshift systematics in the selection, finding that this seems to be a major source of contamination in our sample. A preliminary analysis shows that MSCGs exhibit negative internal colour gradients, consistent with a passive evolution of these systems. We find that the number density of MSCGs is only mildly consistent with predictions from simulations at z > 0.2, while no such system is found at z < 0.2.

  1. ALMA Reveals Potential Localized Dust Enrichment from Massive Star Clusters in II Zw 40

    Science.gov (United States)

    Consiglio, S. Michelle; Turner, Jean L.; Beck, Sara; Meier, David S.

    2016-12-01

    We present subarcsecond images of submillimeter CO and continuum emission from a local galaxy forming massive star clusters: the blue compact dwarf galaxy II Zw 40. At ˜0.″4 resolution (20 pc), the CO(3-2), CO(1-0), 3 mm, and 870 μm continuum maps illustrate star formation on the scales of individual molecular clouds. Dust contributes about one-third of the 870 μm continuum emission, with free-free accounting for the rest. On these scales, there is not a good correspondence between gas, dust, and free-free emission. Dust continuum is enhanced toward the star-forming region as compared to the CO emission. We suggest that an unexpectedly low and spatially variable gas-to-dust ratio is the result of rapid and localized dust enrichment of clouds by the massive clusters of the starburst.

  2. An Apparent Precessing Helical Outflow from a Massive Evolved Star: Evidence for Binary Interaction

    CERN Document Server

    Lau, Ryan M; Herter, Terry L; Morris, Mark R; Mills, Elisabeth A C; Ressler, Michael E

    2015-01-01

    Massive, evolved stars play a crucial role in the metal-enrichment, dust budget, and energetics of the interstellar medium; however, the details of their evolution are uncertain because of their rarity and short lifetimes before exploding as supernovae. Discrepancies between theoretical predictions from single-star evolutionary models and observations of massive stars have evoked a shifting paradigm that implicates the importance of binary interaction. We present mid- to far-infrared observations from the Stratospheric Observatory for Infrared Astronomy (SOFIA) of a conical ``helix'' of warm dust ($\\sim180$ K) that appears to extend from the Wolf-Rayet star WR102c. Our interpretation of the helix is a precessing, collimated outflow that emerged from WR102c during a previous evolutionary phase as a rapidly rotating luminous blue variable. We attribute the precession of WR102c to gravitational interactions with an unseen compact binary companion whose orbital period can be constrained to $800\\,\\mathrm{d}

  3. Stellar feedback from a massive Super Star Cluster in the Antennae merger

    Science.gov (United States)

    Herrera, Cinthya N.; Boulanger, Francois

    2017-03-01

    Stellar feedback from massive stars can unbind and disperse large amount of molecular gas, affecting the star formation efficiency. Based on ALMA and VLT observations in the Antennae galaxies we study a massive (~ 107 M⊙) and young (~ 3 Myr) SSC, B1, associated with compact molecular and ionized emission, which suggests that it is embedded in its parent cloud. However, we found contradictories and puzzling results on the structure and dynamics of the matter around the cluster, indicating that SSC B1 is not embedded in its parent cloud after all. We propose that radiation pressure was highly enhanced at the early stages of the SSC formation, disrupting the parent cloud in parent cloud in the more extended CO gas. Higher angular resolution observations are needed to validate this interpretation and to understand the origin and fate of the component seen to be associated with SSC B1.

  4. Dynamical masses and non-homology of massive elliptical galaxies grown by dry mergers

    CERN Document Server

    Frigo, Matteo

    2016-01-01

    We study whether dry merger-driven size growth of massive elliptical galaxies depends on their initial structural concentration, and analyse the validity of the homology hypothesis for virial mass determination in massive ellipticals grown by dry mergers. High-resolution simulations of a few realistic merger trees, starting with compact progenitors of different structural concentrations (S\\'ersic indices n), show that galaxy growth has little dependence on the initial S\\'ersic index (larger n leads to slightly larger size growth), and depends more on other particulars of the merger history. We show that the deposition of accreted matter in the outer parts leads to a systematic and predictable breaking of the homology between remnants and progenitors, which we characterize through the evolution, during the course of the merger history, of virial coefficients K = GM/Re \\sigma^2 associated to the most commonly-used dynamical and stellar mass parameters. The virial coefficient for the luminous mass, K , is about ...

  5. ALMA Reveals Potential Localized Dust Enrichment from Massive Star Clusters in II Zw 40

    CERN Document Server

    Consiglio, S Michelle; Beck, Sara; Meier, David S

    2016-01-01

    We present subarcsecond images of submillimeter CO and continuum emission from a local galaxy forming massive star clusters: the blue compact dwarf galaxy II Zw 40. At $\\sim$0.4" resolution (20 pc), the CO(3-2), CO(1-0), 3mm and 870${\\mu}$m continuum maps illustrate star formation on the scales of individual molecular clouds. Dust contributes about a third of the 870${\\mu}$m continuum emission, with free-free accounting for the rest. On these scales, there is not a good correspondence between gas, dust, and free-free emission. Dust continuum is enhanced toward the star-forming region as compared to the CO emission. We suggest that an unexpectedly low and spatially variable gas-to-dust ratio is the result of massive clusters of the starburst.

  6. Baryon currents in QCD with compact dimensions

    CERN Document Server

    Lucini, B; Pica, C; Lucini, Biagio; Patella, Agostino; Pica, Claudio

    2007-01-01

    On a compact space with non-trivial cycles, for sufficiently small values of the radii of the compact dimensions, SU(N) gauge theories coupled with fermions in the fundamental representation spontaneously break charge conjugation, time reversal and parity. We show at one loop in perturbation theory that physical signature for this phenomenon is a non-zero baryonic current wrapping around the compact directions. The persistence of this current beyond the perturbative regime is checked by lattice simulations.

  7. Constraints on Massive Star Formation: Cygnus OB2 was always an Association

    CERN Document Server

    Wright, Nicholas J; Goodwin, Simon P; Drake, Jeremy J

    2013-01-01

    We examine substructure and mass segregation in the massive OB association Cygnus OB2 to better understand its initial conditions. Using a well understood Chandra X-ray selected sample of young stars we find that Cyg OB2 exhibits considerable physical substructure and has no evidence for mass segregation, both indications that the association is not dynamically evolved. Combined with previous kinematical studies we conclude that Cyg OB2 is dynamically very young, and what we observe now is very close to its initial conditions: Cyg OB2 formed as a highly substructured, unbound association with a low volume density (< 100 stars/pc^3). This is inconsistent with the idea that all stars form in dense, compact clusters. The massive stars in Cyg OB2 show no evidence for having formed particularly close to one another, nor in regions of higher than average density. Since Cyg OB2 contains stars as massive as ~100 Mo this result suggests that very massive stars can be born in relatively low-density environments. Thi...

  8. A massive molecular outflow in the dense dust core AGAL G337.916-00.477

    CERN Document Server

    Torii, Kazufumi; Hasegawa, Keisuke; Ohama, Akio; Yamamoto, Hiroaki; Tachihara, Kengo; Tokuda, Kazuki; Onishi, Toshikazu; Hattori, Yasuki; Ishihara, Daisuke; Kaneda, Hidehiro; Fukui, Yasuo

    2016-01-01

    The massive molecular outflows erupting from the high-mass young stellar objects provide important clues to understand the mechanism of the high-mass star formation. Based on new CO J=3-2 and J=1-0 observations with ASTE and Mopra, we discovered a new and very young massive bipolar outflow associated with the dense dust core AGAL G337.916-00.477 (AGAL337.9-S), located at 3.2kpc. The outflow is very compact less than 1,pc and is not fully resolved in the angular resolutions of ASTE and Mopra. The maximum velocities of the outflow lobes are as high as 30-40km/s. The total source luminosity for AGAL337.9-S was estimated to be ~10^5 Lo. Compared with the other massive outflows, we concluded that the AGAL337.9-S outflow is certainly one of the most massive and youngest high-mass young stellar objects ever known in the Milky Way. The short dynamical timescale ~10^4yrs of the outflow and mid-infrared-faint spectral energy distribution of AGAL337.9-S support for its young age. We also found that another dust core AGA...

  9. Detection of Prominent Stellar Disks in the Progenitors of Present-day Massive Elliptical Galaxies

    CERN Document Server

    Davari, Roozbeh H; Mobasher, Bahram; Canalizo, Gabriela

    2016-01-01

    Massive galaxies at higher redshifts ($\\emph{z}$ $>$ 2) show different characteristics from their local counterparts: They are compact and most likely have a disk. In this study, we trace the evolution of local massive galaxies by performing a detailed morphological analysis, namely, fitting single S\\'{e}rsic profiles and performing bulge+disk decompositions. We analyze $\\sim$ 250 massive galaxies selected from all CANDELS fields (COSMOS, UDS, EGS, GOODS-South and GOODS-North). We confirm that both star-forming and quiescent galaxies increase their sizes significantly from $\\emph{z}$ $\\approx$ 2.5 to the present day. The global S\\'{e}rsic index of quiescent galaxies increases over time (from $n$ $\\approx$ 2.5 to $n$ $>$ 4), while that of star-forming galaxies remains roughly constant ($n$ $\\approx$ 2.5). By decomposing galaxy profiles into bulge+disk components, we find that massive galaxies at high redshift have prominent stellar disks, which are also evident from visual inspection of the images. By $z$ $\\ap...

  10. Massive relic galaxies challenge the co-evolution of SMBHs and their host galaxies

    CERN Document Server

    Ferré-Mateu, Anna; Trujillo, Ignacio; Balcells, Marc; Bosch, Remco C E van den

    2015-01-01

    We study a sample of eight massive galaxies that are extreme outliers (3-5$\\sigma$) in the M$_{\\bullet}$-M$_\\mathrm{bulge}$ local scaling relation. Two of these galaxies are confirmed to host extremely large super massive black holes (SMBHs), whereas the virial mass estimates for the other six are also consistent with having abnormally large SMBHs. From the analysis of their star formation histories and their structural properties we find that all these extreme outliers can be considered as relic galaxies from the early (z$\\sim$2) Universe: i.e. they are compact (R$_{\\mathrm{e}}$$<$2 kpc) and have purely old stellar populations (t$\\gtrsim$10 Gyr). In order to explain the nature of such deviations from the local relations, we propose a scenario in which the hosts of these \\"uber-massive SMBHs are galaxies that have followed a different evolutionary path than the two-phase growth channel assumed for massive galaxies. Once the SMBH and the core of the galaxy are formed at z$\\sim$2, the galaxy skips the second...

  11. GRay: a Massively Parallel GPU-Based Code for Ray Tracing in Relativistic Spacetimes

    CERN Document Server

    Chan, Chi-kwan; Ozel, Feryal

    2013-01-01

    We introduce GRay, a massively parallel integrator designed to trace the trajectories of billions of photons in a curved spacetime. This GPU-based integrator employs the stream processing paradigm, is implemented in CUDA C/C++, and runs on nVidia graphics cards. The peak performance of GRay using single precision floating-point arithmetic on a single GPU exceeds 300 GFLOP (or 1 nanosecond per photon per time step). For a realistic problem, where the peak performance cannot be reached, GRay is two orders of magnitude faster than existing CPU-based ray tracing codes. This performance enhancement allows more effective searches of large parameter spaces when comparing theoretical predictions of images, spectra, and lightcurves from the vicinities of compact objects to observations. GRay can also perform on-the-fly ray tracing within general relativistic magnetohydrodynamic algorithms that simulate accretion flows around compact objects. Making use of this algorithm, we calculate the properties of the shadows of K...

  12. How robust are the size measurements of high-redshift compact galaxies?

    Energy Technology Data Exchange (ETDEWEB)

    Davari, Roozbeh [University of California, Riverside 900 University Avenue, Riverside, CA 92521 (United States); Ho, Luis C. [The Observatories of the Carnegie Institution for Science 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Peng, Chien Y. [Giant Magellan Telescope Organization 251 South Lake Avenue, Suite 300 Pasadena, CA 91101 (United States); Huang, Song [School of Space Science and Astronomy, Nanjing University, Nanjing 210093 (China)

    2014-05-20

    Massive quiescent galaxies at z ≈ 2 are apparently much more compact than galaxies of comparable mass today. How robust are these size measurements? We perform comprehensive simulations to determine possible biases and uncertainties in fitting single-component light distributions to real galaxies. In particular, we examine the robustness of the measurements of the luminosity, size, and other structural parameters. We devise simulations with increasing realism to systematically disentangle effects due to the technique (specifically using GALFIT) and the intrinsic structures of the galaxies. By accurately capturing the detailed substructures of nearby elliptical galaxies and then rescaling their sizes and signal-to-noise to mimic galaxies at different redshifts, we confirm that the massive quiescent galaxies at z ≈ 2 are significantly more compact intrinsically than their local counterparts. Their observed compactness is not a result of missing faint outer light due to systematic errors in modeling. In fact, we find that fitting multi-component galaxies with a single Sérsic profile, the procedure most commonly adopted in the literature, biases the inferred sizes higher by up to 10%-20%, which accentuates the amount of size evolution required. If the sky estimation has been done robustly and the model for the point-spread function is fairly accurate, GALFIT can retrieve the properties of single-component galaxies over a wide range of signal-to-noise ratios without introducing any systematic errors.

  13. A COMPACT GROUP OF GALAXIES AT Z = 2.48 HOSTING AN AGN-DRIVEN OUTFLOW

    Energy Technology Data Exchange (ETDEWEB)

    Shih, Hsin-Yi [Gemini Observatory, 670 N Aohoku Place, Hilo, HI 96720 (United States); Stockton, Alan, E-mail: jshih@gemini.edu, E-mail: stockton@ifa.hawaii.edu [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States)

    2015-12-10

    We present observations of a remarkable compact group of galaxies at z = 2.48. Four galaxies, all within 40 kpc of each other, surround a powerful high-redshift radio source. This group comprises two compact red passive galaxies and a pair of merging galaxies. One of the red galaxies, with an apparent stellar mass of 3.6 × 10{sup 11}M{sub ⊙} and an effective radius of 470 pc, is one of the most extreme examples of a massive quiescent compact galaxy found so far. One of the pair of merging galaxies hosts the active galactic nucleus (AGN) producing the large powerful radio structure. The merger is massive and enriched, consistent with the mass–metallicity relation expected at this redshift. Close to the merging nuclei, the emission lines exhibit broad and asymmetric profiles that suggest outflows powered either by a very young expanding radio jet or by AGN radiation. At ≳50 kpc from the system, we found a fainter extended-emission region that may be a part of a radio-jet-driven outflow.

  14. Compact Solar Combisystem for an Apartment Building

    National Research Council Canada - National Science Library

    Bolonina, Alona; Rochas, Claudio; Kibure, Inese; Rosa, Marika; Blumberga, Dagnija

    2010-01-01

    ... _________________________________________________________________________________ Volume 4 29 Compact Solar Combisystem for an Apartment Building Alona Bolonina, Institute of Energy Systems and Environment, Riga Technical University, Claudio...

  15. On compact generation of some deformed surfaces

    CERN Document Server

    Lowen, Wendy

    2012-01-01

    We obtain a theorem which allows to prove compact generation of derived categories of Grothendieck categories, based upon certain coverings by localizations. This theorem follows from an application of Rouquier's cocovering theorem in the triangulated context, and it implies Neeman's result on compact generation of quasi-compact separated schemes. We investigate applications of our theorem to non-commutative deformations of such schemes. In general there are obstructions, but for instance our approach yields compact generation of all first order deformations of quasi-projective surfaces.

  16. Computing Decoupled Residuals for Compact Disc Players

    DEFF Research Database (Denmark)

    Odgaard, Peter Fogh; Stoustrup, Jakob; Andersen, Palle

    2006-01-01

    In order to improve Compact Disc Players playability regarding playing Compact Discs with surface faults, like scratches and fingerprints etc, the attention has been put on fault tolerant control schemes. Almost every of those methods are based on fault detection. The standard approach is to use...... a pair of residuals generated by Compact Disc Player. However, these residuals depend on the performance of position servos in the Compact Disc Player. In other publications of the same authors a pair of decoupled residuals is derived. However, the computation of these alternative residuals has been...

  17. Evolution of intermediate mass and massive binary stars: physics, mass loss, and rotation

    CERN Document Server

    Vanbeveren, D

    2016-01-01

    In the present review we discuss the past and present status of the interacting OB-type binary frequency. We critically examine the popular idea that Be-stars and supergiant sgB[e] stars are binary evolutionary products. The effects of rotation on stellar evolution in general, stellar population studies in particular, and the link with binaries will be evaluated. Finally a discussion is presented of massive double compact star binary mergers as possible major sites of chemical enrichment of r-process elements and as the origin of recent aLIGO GW events.

  18. A Cosmological Study in Massive Gravity theory

    CERN Document Server

    Pan, Supriya

    2015-01-01

    A detailed study of the various cosmological aspects in massive gravity theory has been presented in the present work. For the homogeneous and isotropic FLRW model, the deceleration parameter has been evaluated, and, it has been examined whether there is any transition from deceleration to acceleration in recent past, or not. With the proper choice of the free parameters, it has been shown that the massive gravity theory is equivalent to Einstein gravity with a modified Newtonian gravitational constant together with a negative cosmological constant. Also, in this context, it has been examined whether the emergent scenario is possible, or not, in massive gravity theory. Finally, we have done a cosmographic analysis in massive gravity theory.

  19. Gauged/Massive Supergravities in Diverse Dimensions

    CERN Document Server

    Alonso-Alberca, N; Alonso-Alberca, Natxo; Ortin, Tomas

    2003-01-01

    We show how massive/gauged maximal supergravities in 11-n dimensions with SO(n-l,l) gauge groups (and other non-semisimple subgroups of Sl(n,R)) can be systematically obtained by dimensional reduction of ``massive 11-dimensional supergravity''. This series of massive/gauged supergravities includes, for instance, Romans' massive N=2A,d=10 supergravity for n=1, N=2,d=9 SO(2) and SO(1,1) gauged supergravities for n=2, and N=8,d=5 SO(6-l,l) gauged supergravity. In all cases, higher p-form fields get masses through the Stuckelberg mechanism which is an alternative to self-duality in odd dimensions.

  20. Symmetries of Massive and Massless Neutrinos

    CERN Document Server

    Kim, Y S

    2016-01-01

    Wigner's little groups are subgroups of the Lorentz group dictating the internal space-time symmetries of massive and massless particles. These little groups are like O(3) and E(2) for massive and massless particles respectively. While the geometry of the O(3) symmetry is familiar to us, the geometry of the flat plane cannot explain the E(2)-like symmetry for massless particles. However, the geometry of a circular cylinder can explain the symmetry with the helicity and gauge degrees of freedom. It is shown further that the symmetry of the massless particle can be obtained as a zero-mass limit of O(3)-like symmetry for massive particles. It is shown further that the polarization of massless neutrinos is a consequence of gauge invariance, while the symmetry of massive neutrinos is still like O(3).

  1. Massive perturbers in the galactic center

    CERN Document Server

    Perets, H B; Alexander, T; Perets, Hagai B.; Hopman, Clovis; Alexander, Tal

    2006-01-01

    We investigate the role of massive perturbers, such as giant molecular clouds or stellar clusters, in supplying low-angular momentum stars that pass very close to the central massive black hole (MBH) or fall into it. We show that massive pe rturbers can play an important role in supplying both binaries and single stars to the vicinity of the MBH. We discuss possible implications for the ejection of high velocity stars; for the capture of stars on tight orbits around the MBH; for the emission of gravitational waves from low-eccentricity inspiraling stars; and for the origin of the young main sequence B stars observed very near the Gal actic MBH. Massive perturbers may also enhance the the growth rate of MBHs, and may accelerate the dynamical orbital decay of coalescing binary MBHs.

  2. Magnetic monopole solutions with a massive dilaton

    CERN Document Server

    Forgács, Péter; Forgacs, Peter; Gyurusi, Jozsef

    1998-01-01

    Static, spherically symmetric monopole solutions of a spontaneously broken SU(2) gauge theory coupled to a massive dilaton field are studied in detail in function of the dilaton coupling strength and of the dilaton mass.

  3. Current management of massive hemorrhage in trauma

    DEFF Research Database (Denmark)

    Johansson, Pär I; Stensballe, Jakob; Ostrowski, Sisse R

    2012-01-01

    ABSTRACT: Hemorrhage remains a major cause of potentially preventable deaths. Trauma and massive transfusion are associated with coagulopathy secondary to tissue injury, hypoperfusion, dilution, and consumption of clotting factors and platelets. Concepts of damage control surgery have evolved...

  4. TEORÍA DE BILL MUNDY EN EL MECANIZADO DE COBRE CON BROCAS Y MACHOS ESPECIALES BILL MUNDY THEORY. SPECIAL DRILLS AND TAPS TOOLS IN COPPER MACHINING

    Directory of Open Access Journals (Sweden)

    Alejandro Colque C

    2008-06-01

    Full Text Available El mecanizado del cobre, debido a su fluidez, produce una viruta plástica y continua que afecta la calidad superficial de las piezas mecanizadas. El método desarrollado por el ingeniero norteamericano Bill Mundy permite obtener el mejor ángulo de corte para mecanizar un material. El taladrado y el roscado con machos son dos procesos de mecanizado que tienen aspectos en común. Diseños de nuevas herramientas, nuevos materiales y técnicas de mecanizado, mejorías en la lubricación, diferentes velocidades de corte y avances, son variables que se deben estudiar para obtener una menor potencia, mayor duración de la herramienta y buen acabado superficial. En este trabajo probetas de cobre fueron ensayadas a tracción y se determinó experimentalmente el ángulo efectivo de corte, de acuerdo con la teoría de Bill Mundy. Posteriormente se fabricaron nuevas probetas que fueron perforadas con brocas tipo H, N y W, con refrigeración externa, refrigeración interna y en seco. Se usaron machos de máquina de dos y tres hélices. En cada perforación se midió la velocidad de rotación, avance, fuerza de corte, momento torsor y potencia necesaria. Se verificó que en el taladrado de cobre un ángulo mayor de la hélice favorece el desmenuzado de la viruta y disminuye el momento torsor. Brocas con refrigeración interna pueden ser utilizadas con mayores velocidades y muestran una mejor calidad superficial del perforado. Las brocas y machos con un ángulo de ataque próximo al ángulo calculado experimentalmente por la teoría de Bill Mundy muestran un buen comportamiento en el mecanizado y menor consumo de potencia.Copper drilling produces plastic and continuous chip. Bill Mundy a North American engineer developed a method who allows determines experimentally the best cutting angle material machining. Drilling and threading processes has several aspects in common. New tools design, new materials, new techniques, new lubrication and cooling improvement

  5. Desempenho em confinamento de machos bovinos superjovens de diferentes grupos genéticos Feedlot performance of young steers of different genetic groups

    Directory of Open Access Journals (Sweden)

    Fabiano Nunes Vaz

    2013-03-01

    Full Text Available O objetivo deste trabalho foi avaliar o desempenho em confinamento de machos não-castrados superjovens, das raças Hereford, 3/4 Hereford 1/4 Nelore, 5/8 Hereford 3/8 Nelore e 3/4 Charolês 1/4 Nelore, confinados dos sete aos quatorze meses de idade. Os tratamentos foram os quatro genótipos e o delineamento estatístico foi o inteiramente casualizado com quatro tratamentos e oito repetições. Não houve diferença estatística entre os grupos genéticos para peso final e ganho de peso médio diário. O consumo de matéria seca foi maior nos animais com Hereford no genótipo em relação aos 3/4 Charolês, mas em relação a 100 kg de peso vivo, este foi maior nos 3/4 Hereford em relação aos 5/8 Hereford e 3/4 Charolês. O consumo diário ajustado para tamanho metabólico foi superior nos 3/4 Hereford em relação aos 5/8 Hereford e 3/4 Charolês. Machos 3/4 Charolês apresentaram menor consumo de energia digestível que os demais. Ajustado para 100 kg de peso vivo, o consumo de energia digestível foi superior nos Hereford e 3/4 Hereford em relação aos 5/8 Hereford, os quais mostraram maior consumo que os 3/4 Charolês. O desempenho em confinamento de machos superjovens Hereford, 3/4 Hereford e 5/8 Hereford é similar e permite o abate desses genótipos para produção de carne aos quatorze meses, com peso de abate adequado à demanda de mercado.The objective of this work was to evaluate the feedlot performance of young non-castrated Hereford, 3/4 Hereford 1/4 Nellore, 5/8 Hereford 3/8 Nellore and 3/4 Charolais 1/4 Nellore steers, when confined from seven to fourteen months of age. The treatments were the genotypes, and the statistical design was completely randomized, with four treatments and eight replications. There was no statistical difference between the genetic groups for final weight and average daily weight gain. The dry-matter intake was higher in animals with Hereford in the genotype in relation to the 3/4 Charolais, but per

  6. 5G multimedia massive MIMO communications systems

    OpenAIRE

    Ge, Xiaohu; Wang, Haichao; Zi, Ran; Li, Qiang; Ni, Qiang

    2016-01-01

    In the fifth generation (5G) wireless communication systems, a majority of the traffic demands are contributed by various multimedia applications. To support the future 5G multimedia communication systems, the massive multiple-input multiple-output (MIMO) technique is recognized as a key enabler because of its high spectral efficiency. The massive antennas and radio frequency chains not only improve the implementation cost of 5G wireless communication systems but also result in an intense mut...

  7. Exoplanet recycling in massive white-dwarf debris discs

    Science.gov (United States)

    Van Lieshout, Rik

    2017-06-01

    When a star evolves into a white dwarf, the planetary system it hosts can become unstable. Planets in such systems may then be scattered onto star-grazing orbits, leading to their tidal disruption as they pass within the white dwarf’s Roche limit. We study the massive, compact debris discs that may arrise from this process using a combination of analytical estimates and numerical modelling. The discs are gravitationally unstable, resulting in an enhanced effective viscosity due to angular momentum transport associated with self-gravity wakes. For disc masses greater than ~1026 g (corresponding to progenitor objects comparable to the Galilean moons), viscous spreading dominates over Poynting-Robertson drag in the outer parts of the disc. In such massive discs, mass is transported both in- and outwards. When the outward-flowing material spreads beyond the Roche limit, it coagulates into new (minor) planets in a process analogous to the ongoing formation of Saturn’s innermost moonlets. This process recycles a substantial fraction of the original disc mass (tens of percents), with the bulk of the mass locked in a single large body orbitting in a 2:1 mean-motion resonance with the Roche limit. As such, the recycling of a tidally disrupted super-Earth could yield an Earth-mass planet on a 10--20 hr orbit. For white dwarfs with a temperature below 6000-7000 K (corresponding to a cooling age of >1--2 Gyr), this orbit is located in the white dwarf’s habitable zone. The recycling process also creates a string of smaller bodies just outside the Roche limit. These may account for the collection of minor planets postulated to orbit white dwarf WD 1145+017.

  8. Efecto terapéutico del extracto etanólico de Erythroxylum coca spp. en anemia ferropénica inducida en ratas Holtzman macho

    Directory of Open Access Journals (Sweden)

    Evelyn F. Gonzales-Carazas

    2013-01-01

    Full Text Available Introducción: La hoja de coca ha sido usada tradicionalmente con fines medicinales y contiene altos niveles de hierro. Objetivos: Determinar el efecto del extracto etanólico de Erythroxylum coca spp. frente a anemia ferropénica inducida por dieta deficiente en hierro, en ratas Holtzman macho. Diseño: Experimental. Lugar: Laboratorio del Instituto de Patología, Facultad de Medicina, Universidad Nacional Mayor de San Marcos. Material biológico: Dieciocho ratas Holtzman macho de 16 días de edad recién destetadas. Intervenciones: Se formó tres grupos de seis ratas cada uno: a grupo hierro suficiente (HS, recibió 25 g/d de alimento balanceado durante 7 semanas; b grupo hierro deficiente (HD, recibió 25 g/d de dieta ferropénica durante 7 semanas; y, c el grupo hierro deficiente - extracto E. coca (HD-EC, recibió 25 g/d de dieta ferropénica durante 7 semanas y a partir de la semana 5 se agregó 18 g/d de extracto de E. coca. Principales medidas de resultados: Nivel sérico de hemoglobina, peso y talla. Resultados: Al finalizar el tratamiento, se observó aumento significativo de la hemoglobina en el grupo HD-EC (p=0,04. Se encontró diferencia significativa en los niveles séricos de hemoglobina entre los grupos HD-EC y HD (p=0,0062. No se encontró diferencia significativa en los valores de hemoglobina entre los grupos HD-EC y HS (p= 0,06. No se evidenció diferencia en el peso y la talla entre los grupos HD y HD-EC (p=0,20 y p=0,23, respectivamente. Conclusiones: E. coca presenta efecto antianémico experimental, sustentado en los resultados de los niveles de hemoglobina.

  9. MODELO TEÓRICO PARA EXPLICAR LA ACUMULACIÓN DE GOTAS LIPÍDICAS EN EMBRIONES BOVINOS MACHOS O HEMBRAS PRODUCIDOS in vitro

    Directory of Open Access Journals (Sweden)

    OLIVERA MARTHA

    2008-08-01

    Full Text Available La glucosa 6-fosfato deshidrogenasa (G6PD, codificada por un gen ubicado en el cromosoma X, es la enzima limitante de vía de las pentosas fosfato (PF. La entrada de la glucosa así como su flujo y el rendimiento metabólico de esta vía están determinados tanto por los mismos niveles glucosa así como por la actividad de la G6PD. Por esta vía, la glucosa regula la trascripción de varios genes lipogénicos. En algunos embriones hembra producidos in vitro, se registra un retardo en la normal inactivación de uno de sus cromosomas X, lo cual se traduce en una doble actividad de los genes allí ubicados, si se compara con los embriones macho producidos in vitro. Se postula entonces que, la sobre-regulación de la vía PF a consecuencia de la doble dosis de su enzima limitante (G6PD y en presencia de elevados niveles de glucosa (mayores a 2,5 mM en el medio de cultivo, conllevaría a un dimorfismo sexual en relación con la transcripción de los genes Acetil CoA Carboxilasa Alfa (en adelante ACACA, símbolo oficial de la acetyl-Coenzyme A carboxylase alpha, y la Sintetasa de Ácidos Grasos (en edelante FASN, símbolo oficial de la fatty acid synthase que corriente abajo codifican para las enzimas limitantes en la síntesis de lípidos. Este dimorfismo sexual para el fenotipo metabolismo de lípidos, derivaría en una mayor acumulación citoplasmática de gotas lipídicas en los embriones hembra en comparación con los embriones machos que, de ser así, tendría efectos expansivos sobre el metabolismo general, la actividad transcripcional de otros genes y sobre la resistencia a la criopreservación.

  10. MODELO TEÓRICO PARA EXPLICAR LA ACUMULACIÓN DE GOTAS LIPÍDICAS EN EMBRIONES BOVINOS MACHOS O HEMBRAS PRODUCIDOS in vitro

    Directory of Open Access Journals (Sweden)

    OMAR CAMARGO

    2008-01-01

    Full Text Available La glucosa 6-fosfato deshidrogenasa (G6PD, codificada por un gen ubicado en el cromosoma X, es la enzima limitante de vía de las pentosas fosfato (PF. La entrada de la glucosa así como su flujo y el rendimiento metabólico de esta vía están deter- minados tanto por los mismos niveles glucosa así como por la actividad de la G6PD. Por esta vía, la glucosa regula la trascripción de varios genes lipogénicos. En algunos embriones hembra producidos in vitro, se registra un retardo en la normal inactivación de uno de sus cromosomas X, lo cual se traduce en una doble actividad de los genes allí ubicados, si se compara con los embriones macho producidos in vitro. Se postula entonces que, la sobre-regulación de la vía PF a consecuencia de la doble dosis de su enzima limitante (G6PD y en presencia de elevados niveles de glucosa (mayores a 2,5 mM en el medio de cultivo, conllevaría a un dimorfismo sexual en relación con la transcripción de los genes Acetil CoA Carboxilasa Alfa (en adelante ACACA, símbolo oficial de la acetyl-Coenzyme A carboxylase alpha, y la Sintetasa de Ácidos Grasos (en edelante FASN, símbolo oficial de la fatty acid synthase que corriente abajo codifican para las enzimas limitantes en la síntesis de lípidos. Este dimorfismo sexual para el fenotipo metabolismo de lípidos, derivaría en una mayor acumulación citoplasmática de gotas lipídicas en los embriones hembra en comparación con los embriones machos que, de ser así, tendría efectos expansivos sobre el metabolismo general, la actividad transcripcional de otros genes y sobre la resistencia a la criopreservación.

  11. Studies of accelerated compact toruses

    Energy Technology Data Exchange (ETDEWEB)

    Hartman, C.W.; Eddleman, J.; Hammer, J.H.

    1983-01-04

    In an earlier publication we considered acceleration of plasma rings (Compact Torus). Several possible accelerator configurations were suggested and the possibility of focusing the accelerated rings was discussed. In this paper we consider one scheme, acceleration of a ring between coaxial electrodes by a B/sub theta/ field as in a coaxial rail-gun. If the electrodes are conical, a ring accelerated towards the apex of the cone undergoes self-similar compression (focusing) during acceleration. Because the allowable acceleration force, F/sub a/ = kappaU/sub m//R where (kappa < 1), increases as R/sup -2/, the accelerating distance for conical electrodes is considerably shortened over that required for coaxial electrodes. In either case, however, since the accelerating flux can expand as the ring moves, most of the accelerating field energy can be converted into kinetic energy of the ring leading to high efficiency.

  12. Gravitational waves from compact objects

    Institute of Scientific and Technical Information of China (English)

    José Antonio de Freitas Pacheco

    2010-01-01

    Large ground-based laser beam interferometers are presently in operation both in the USA (LIGO) and in Europe (VIRGO) and potential sources that might be detected by these instruments are revisited. The present generation of detectors does not have a sensitivity high enough to probe a significant volume of the universe and,consequently, predicted event rates are very low. The planned advanced generation of interferometers will probably be able to detect, for the first time, a gravitational signal. Advanced LIGO and EGO instruments are expected to detect few (some): binary coalescences consisting of either two neutron stars, two black holes or a neutron star and a black hole. In space, the sensitivity of the planned LISA spacecraft constellation will allow the detection of the gravitational signals, even within a "pessimistic" range of possible signals, produced during the capture of compact objects by supermassive black holes, at a rate of a few tens per year.

  13. A Compact UWB Diversity Antenna

    Directory of Open Access Journals (Sweden)

    Hui Zhao

    2014-01-01

    Full Text Available A compact printed ultrawideband (UWB diversity antenna with a size of 30 mm × 36 mm operating at a frequency range of 3.1–10.6 GHz is proposed. The antenna is composed of two semielliptical monopoles fed by two microstrip lines. Two semicircular slots, two rectangular slots, and one stub are introduced in the ground plane to adjust the impedance bandwidth of the antenna and improve the isolation between two feeding ports. The simulated and measured results show that impedance bandwidth of the proposed antenna can cover the whole UWB band with a good isolation of < −15 dB. The radiation patterns, peak antenna gain, and envelope correlation coefficient are also measured and discussed. The measured results show that the proposed antenna can be a good candidate for some portable MIMO/diversity UWB applications.

  14. Compact Digital High Voltage Charger

    CERN Document Server

    Li, Ge

    2005-01-01

    The operation of classical resonant circuit developed for the pulse energizing is investigated. The HV pulse or generator is very compact by a soft switching circuit made up of IGBT working at over 30 kHZ. The frequencies of macro pulses andμpulses can be arbitrarily tuned below resonant frequency to digitalize the HV pulse power. Theμpulses can also be connected by filter circuit to get the HVDC power. The circuit topology is given and its novel control logic is analyzed by flowchart. The circuit is part of a system consisting of a AC or DC LV power supply, a pulse transformer, the pulse generator implemented by LV capacitor and leakage inductance of the transformer, a HV DC or pulse power supply and the charged HV capacitor of the modulators.

  15. Saloplastics: processing compact polyelectrolyte complexes.

    Science.gov (United States)

    Schaaf, Pierre; Schlenoff, Joseph B

    2015-04-17

    Polyelectrolyte complexes (PECs) are prepared by mixing solutions of oppositely charged polyelectrolytes. These diffuse, amorphous precipitates may be compacted into dense materials, CoPECs, by ultracentrifugation (ucPECs) or extrusion (exPECs). The presence of salt water is essential in plasticizing PECs to allow them to be reformed and fused. When hydrated, CoPECs are versatile, rugged, biocompatible, elastic materials with applications including bioinspired materials, supports for enzymes and (nano)composites. In this review, various methods for making CoPECs are described, as well as fundamental responses of CoPEC mechanical properties to salt concentration. Possible applications as synthetic cartilage, enzymatically active biocomposites, self-healing materials, and magnetic nanocomposites are presented.

  16. CIM—Compact intensity modulation

    Science.gov (United States)

    Bleuel, M.; Lang, E.; Gähler, R.; Lal, J.

    2008-07-01

    Compact intensity modulation (CIM), a new method to modulate the intensity of a neutron beam is demonstrated. CIM allows the production of arbitrary signals where the focus point can be chosen and changed without any constraints. A novel feature in this technique compared to spin echo techniques is that the neutron polarization is kept parallel or anti-parallel to the static fields during the passage through the magnetic fields and the beating pattern at the detector is produced by an amplitude modulation (AM) of the adiabatic RF-spin flippers rather than Larmor precession like in neutron spin echo (NSE) instruments; thus, the achievable contrast is very high and the instrument resolution can be changed very quickly. This gives the fascinating possibility at pulsed neutron sources to sweep the modulation frequency of the flippers in order to increase dynamic resolution range during the same neutron pulse.

  17. Spiral Inflector For Compact Cyclotron

    CERN Document Server

    Karamysheva, G A

    2004-01-01

    Compact cyclotron for explosives detection by nuclear resonance absorption of γ-rays in nitrogen is under development [1] Cyclotron will be equipped with the external ion source. The injection system consists of a double-drift beam bunching system, a spiral inflector, beam diagnostics, focusing and adjustment elements [2]. The spiral inflector for ion bending from axial to median plane is used. Computer model of spiral inflector for the Customs cyclotron is developed. 3D electrostatic field calculations of the designed inflector are performed. Calculated electric field map and magnetic field map of the cyclotron [3] are used for beam dynamic simulations. Numeric simulations are carried out for 500 particles using code for calculation of particle dynamics by integration of differential equations in Cartesian coordinate system written in MATLAB. Direct Coulomb particle-to-particle method is used to take into account space-charge effects.

  18. The Compactness of Construction Grammars

    CERN Document Server

    Zadrozny, W

    1995-01-01

    We present an argument for {\\em construction grammars} based on the minimum description length (MDL) principle (a formal version of the Ockham Razor). The argument consists in using linguistic and computational evidence in setting up a formal model, and then applying the MDL principle to prove its superiority with respect to alternative models. We show that construction-based representations are at least an order of magnitude more compact that the corresponding lexicalized representations of the same linguistic data. The result is significant for our understanding of the relationship between syntax and semantics, and consequently for choosing NLP architectures. For instance, whether the processing should proceed in a pipeline from syntax to semantics to pragmatics, and whether all linguistic information should be combined in a set of constraints. From a broader perspective, this paper does not only argue for a certain model of processing, but also provides a methodology for determining advantages of different...

  19. Compact RFID Enabled Moisture Sensor

    Directory of Open Access Journals (Sweden)

    U. H. Khan

    2016-09-01

    Full Text Available This research proposes a novel, low-cost RFID tag sensor antenna implemented using commercially available Kodak photo-paper. The aim of this paper is to investigate the possibility of stable, RFID centric communication under varying moisture levels. Variation in the frequency response of the RFID tag in presence of moisture is used to detect different moisture levels. Combination of unique jaw shaped contours and T-matching network is used for impedance matching which results in compact size and minimal ink consumption. Proposed tag is 1.4 × 9.4 cm2 in size and shows optimum results for various moisture levels upto 45% in FCC band with a bore sight read range of 12.1 m.

  20. Compact oleic acid in HAMLET.

    Science.gov (United States)

    Fast, Jonas; Mossberg, Ann-Kristin; Nilsson, Hanna; Svanborg, Catharina; Akke, Mikael; Linse, Sara

    2005-11-07

    HAMLET (human alpha-lactalbumin made lethal to tumor cells) is a complex between alpha-lactalbumin and oleic acid that induces apoptosis in tumor cells, but not in healthy cells. Heteronuclear nuclear magnetic resonance (NMR) spectroscopy was used to determine the structure of 13C-oleic acid in HAMLET, and to study the 15N-labeled protein. Nuclear Overhauser enhancement spectroscopy shows that the two ends of the fatty acid are in close proximity and close to the double bond, indicating that the oleic acid is bound to HAMLET in a compact conformation. The data further show that HAMLET is a partly unfolded/molten globule-like complex under physiological conditions.