10,778 research outputs found
Molecular Gas Content of HI Monsters and Implications to Cold Gas Content Evolution in Galaxies
We present 12CO (J=1-0) observations of a sample of local galaxies
(0.04<z<0.08) with a large neutral hydrogen reservoir, or "HI monsters". The
data were obtained using the Redshift Search Receiver on the FCRAO 14 m
telescope. The sample consists of 20 HI-massive galaxies with M(HI)>3e10Msun
from the ALFALFA survey and 8 LSBs with a comparable M(HI) (>1.5e10Msun). Our
sample selection is purely based on the amount of neutral hydrogen, thereby
providing a chance to study how atomic and molecular gas relate to each other
in these HI-massive systems. We have detected CO in 15 out of 20 ALFALFA
selected galaxies and 4 out of 8 LSBs with molecular gas mass M(H2) of
(1-11)e9Msun. Their total cold gas masses of (2-7e10Msun make them some of the
most gas-massive galaxies identified to date in the Local Universe. Observed
trends associated with HI, H2, and stellar properties of the HI massive
galaxies and the field comparison sample are analyzed in the context of
theoretical models of galaxy cold gas content and evolution, and the importance
of total gas content and improved recipes for handling spatially differentiated
behaviors of disk and halo gas are identified as potential areas of improvement
for the modeling.Comment: 18 pages, 11 figures, 2 tables; Accepted for publication in MNRA
Interactions in sustainable supply chain management: a framework review
Purpose – This study evaluates the research conducted among the interim, dyadic interactions that bridge the stand-alone measures of economic, environmental, and social performance and the level of sustainability, as suggested in the Carter & Rogers (2008) framework.
Design/methodology/approach – This paper conducts a systematic literature review based on the Tranfield et al. (2003) method of the articles published in 13 major journals in the area of supply chain management between the years of 2010 and 2016. Results were analyzed using an expert panel.
Findings – The area of research between environmental and social performance is sparse and relegated to empirical investigation. As an important area of interaction, this area needs more research to answer the how and why questions. The economic activity seems to be the persistent theme among the interactions.
Research implications – The literature on the “ES” interactions is lacking in both theoretical and analytical content. Studies explaining the motivations, optimal levels, and context that drive these interactions are needed. The extant research portrays economic performance as if it cannot be sacrificed for social welfare. This approach is not in line with the progressive view of SSCM but instead the binary view with an economic emphasis.
Practical implications – To improve sustainability, organizations need the triple bottom line (TBL) framework that defines sustainability in isolation. However, they also need to understand how and why these interactions take place that drive sustainability in organizations.
Originality/value – This is the first study to examine the literature specifically dedicated to the essential, interim, dyadic interactions that bridge the gap between stand-alone performance and the TBL that creates true sustainability. It also shows how the literature views the existence of sustainability is progressive, but many describe sustainability as binary. It is possible that economic sustainability is binary, and progressive characterizations of SSCM could be the reason behind the results favoring economic performance over environmental and social
Electrodynamics of the vanadium oxides VO2 and V2O3
The optical/infrared properties of films of vanadium dioxide (VO2) and
vanadium sesquioxide (V2O3) have been investigated via ellipsometry and
near-normal incidence reflectance measurements from far infrared to ultraviolet
frequencies. Significant changes occur in the optical conductivity of both VO2
and V2O3 across the metal-insulator transitions at least up to (and possibly
beyond) 6 eV. We argue that such changes in optical conductivity and electronic
spectral weight over a broad frequency range is evidence of the important role
of electronic correlations to the metal-insulator transitions in both of these
vanadium oxides. We observe a sharp optical transition with possible final
state (exciton) effects in the insulating phase of VO2. This sharp optical
transition occurs between narrow a1g bands that arise from the
quasi-one-dimensional chains of vanadium dimers. Electronic correlations in the
metallic phases of both VO2 and V2O3 lead to reduction of the kinetic energy of
the charge carriers compared to band theory values, with paramagnetic metallic
V2O3 showing evidence of stronger correlations compared to rutile metallic VO2.Comment: 11 pages, 7 figure
The Deep SWIRE Field I. 20cm Continuum Radio Observations: A Crowded Sky
We present results from deep radio observations taken with the VLA at a
center frequency of 1400 MHz cover a region of the SWIRE Spitzer Legacy survey,
centered at 10 46 00, 59 01 00 (J2000). The reduction and cataloging of the
radio sources are described. The survey presented is the deepest so far in
terms of the radio source density on the sky. Perhaps surprisingly, the sources
down to the bottom of the catalog have median angular sizes greater than 1
arcsecond, like their cousins 10-100 times stronger. If the log N - log S
normalization remains constant at the lowest flux densities, there are about 6
sources per square arcminute down to 15 microJy at 20cm. Given the finite
source sizes this implies we may reach the natural confusion limit near 1
microJy.Comment: 29 pages, 11 figures, accepted A
A Study of CO Emission in High Redshift QSOs Using the Owens Valley Millimeter Array
Searches for CO emission in high-redshift objects have traditionally suffered
from the accuracy of optically-derived redshifts due to lack of bandwidth in
correlators at radio observatories. This problem has motivated the creation of
the new COBRA continuum correlator, with 4 GHz available bandwidth, at the
Owens Valley Radio Observatory Millimeter Array. Presented here are the first
scientific results from COBRA. We report detections of redshifted CO(J=3-2)
emission in the QSOs SMM J04135+10277 and VCV J140955.5+562827, as well as a
probable detection in RX J0911.4+0551. At redshifts of z=2.846, z=2.585, and
z=2.796, we find integrated CO flux densities of 5.4 Jy km/s, 2.4 Jy km/s, and
2.9 Jy km/s for SMM J04135+10277, VCV J140955.5+562827, and RX J0911.4+0551,
respectively, over linewidths of Delta(V_{FWHM}) ~ 350 km/s. These
measurements, when corrected for gravitational lensing, correspond to molecular
gas masses of order M(H_2) ~ 10^{9.6-11.1} solar masses, and are consistent
with previous CO observations of high-redshift QSOs. We also report 3-sigma
upper limits on CO(3-2) emission in the QSO LBQS 0018-0220 of 1.3 Jy km/s. We
do not detect significant 3mm continuum emission from any of the QSOs, with the
exception of a tentative (3-sigma) detection in RX J0911.4+0551 of S_{3mm}=0.92
mJy/beam.Comment: 18 pages, 5 figures, 2 tables, accepted to ApJ. Changes made for
version 2: citations added, 2 objects added to Table 2 and Figure
Assisted Tachyonic Inflation
The model of inflation with a single tachyon field generates larger
anisotropy and has difficulties in describing the formation of the Universe .
In this paper we consider a model with multi tachyon fields and study the
assisted inflationary solution. Our results show that this model satisfies the
observation.Comment: 5 pages, no figures, a revised version and reference adde
The versatile terahertz reflection and transmission spectrometer with the location of objects of researches in the horizontal plane
The experimental setup of versatile pulse terahertz reflection and transmission spectrometer and operation concept were described. Using this setup the temporary forms of THz signal reflected from and transmitted through the samples like amino acids, dental tissue and normal were obtained. The possibility of structural determination of powdered media was demonstrated using this method
The dust emission SED of X-ray emitting regions in Stephan's Quintet
We analysed the Spitzer maps of Stephan's Quintet in order to investigate the
nature of the dust emission associated with the X-ray emitting regions of the
large scale intergalactic shock and of the group halo. This emission can in
principle be powered by dust-gas particle collisions, thus providing efficient
cooling of the hot gas. However the results of our analysis suggest that the
dust emission from those regions is mostly powered by photons. Nonetheless dust
collisional heating could be important in determining the cooling of the IGM
gas and the large scale star formation morphology observed in SQ.Comment: Conference proceedings IAU Symposium 284 "The Spectral energy
distribution of galaxies", 5-9 September 2011, Preston, U
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