3,974 research outputs found
FMCG brand, supermarket chain and consumer relationships
The new FMCG (fast-moving consumer goods) landscape has increasingly been dominated by large retail chain stores that are highly concentrated. In the FMCG equation, the locus of power has shifted from manufacturers to retailers, particularly to large supermarket chains. Accepted views of brands have however tended to put emphasis on the relationship of manufacturer brands with consumers, thereby largely neglecting brand – reseller relationships. This has been identified as a gap in the literature. The research intends to address this gap by adopting a holistic study that encompasses a three-way brand, supermarket chain, and consumer relationship. The objective of the study is theory building
Insights into galaxy evolution from mid-infrared wavelengths
In this paper, I have attempted to highlight key results from deep extragalactic surveys at mid-infrared wavelengths. I discuss advances in our understanding of dust enshrouded star-formation and AGN activity at 0 3 will become possible only with future facilities like ALMA. Currently, the presence of dust can only be assessed in a small fraction of the youngest starbursts at z > 5 by looking for redshifted large equivalent width Hα emission in broadband filters like the IRAC 4.5μm passband. Hα to UV ratios in these objects are a tracer of dust extinction and measuring this ratio in GOODS galaxies indicate dust in ~20% of star-forming galaxies at z > 5. Finally, implications for reionization based on the measured stellar mass density and star-formation rates of galaxies at these redshifts are discussed
Unveiling the Progenitors of GRBs through Observations of their Host Galaxies
I discuss the possibility of differentiating between popular models for
gamma-ray bursts by using multiwavelength observations to constrain the
characteristics of their host galaxies, in particular the age of the stellar
populations.Comment: 3 pages, Proceedings of "Gamma-Ray Burst and Afterglow Astronomy
2001: A Workshop Celebrating the First Year of the HETE Mission", AI
Arp102B: An ADAF and a Torus ?
Arp102B is a nearby radio galaxy which displays the presence of double peaked
Balmer emission lines. Sub-arcsec Keck mid-infrared imaging and Spitzer
spectroscopy reveal a spatially compact mid-infrared source which displays
tentative evidence for variability. The F spectral
energy distribution is suggestive of an advection dominated accretion flow. The
absence of dust features over the 5-40 micron range make it unlikely that
thermal dust emission dominates the mid-infrared luminosity. We also detect the
presence of molecular hydrogen in emission which is asymmetrically redshifted
by ~500-1000 km/s from the systemic velocity of the galaxy. Since the
forbidden, low ionization lines in this galaxy are at the systemic velocity, we
suggest that the molecular hydrogen emission arises from a rotating molecular
gas structure surrounding the nuclear black hole at a distance of ~1 pc.Comment: 4 pages, 3 figures, Conference proceedings to appear in "The Central
Engine of Active Galactic Nuclei", ed. L. C. Ho and J.-M. Wang (San
Francisco: ASP
Convection in vertical Bridgman configurations
We are interested in tracing the convective profiles of vertical Bridgman growth in two configurations, the pure Rayleigh convective mode and the combined Rayleigh-Marangoni mode. In order to do so, we conducted a numerical investigation that involved a finite volume calculation. The governing equations were integrated about a cell volume, using the Gauss Theorem and the volume variables like temperature and velocity were related to the surface variables. In order to solve for the pressure field, we employed the continuity equation and the residuals resulted in a Poisson equation. Results and comments for the Rayleigh and Marangoni problems in a vertical cylinder or Bridgman configuration are given
Searching for the Highest Redshift Sources in 250-500 μm Submillimeter Surveys
We explore a technique for identifying the highest redshift (z>4) sources in Herschel/SPIRE and BLAST submillimeter surveys by localizing the position of the far-infrared dust peak. Just as Spitzer/IRAC was used to identify stellar "bump" sources, the far-IR peak is also a redshift indicator; although the latter also depends on the average dust temperature. We demonstrate the wide range of allowable redshifts for a reasonable range of dust temperatures and show that it is impossible to constraint the redshift of individual objects using solely the position of the far-IR peak. By fitting spectral energy distribution models to simulated Herschel/SPIRE photometry we show the utility of radio and/or far-infrared data in breaking this degeneracy. With prior knowledge of the dust temperature distribution it is possible to obtain statistical samples of high redshift submillimeter galaxy (SMG) candidates. We apply this technique to the BLAST survey of ECDFS to constrain the number of dusty galaxies at z>4. We find 8 ± 2 galaxies with flux density ratios of S_(500)_>S_(350); this sets an upper limit of 17 ± 4 deg^(–2) if we assume all are at z>4. This is 45 mJy (L_(IR)>2 × 10^(13) L_☉ for z>4). Modeling with conventional temperature and redshift distributions estimates the percentage of these 500 μm peak galaxies at z>4 to be between 10% and 85%. Our results are consistent with other estimates of the number density of very high redshift SMGs and follow the decline in the star formation rate density at z>4
On the Gaussian Many-to-One X Channel
In this paper, the Gaussian many-to-one X channel, which is a special case of
general multiuser X channel, is studied. In the Gaussian many-to-one X channel,
communication links exist between all transmitters and one of the receivers,
along with a communication link between each transmitter and its corresponding
receiver. As per the X channel assumption, transmission of messages is allowed
on all the links of the channel. This communication model is different from the
corresponding many-to-one interference channel (IC). Transmission strategies
which involve using Gaussian codebooks and treating interference from a subset
of transmitters as noise are formulated for the above channel. Sum-rate is used
as the criterion of optimality for evaluating the strategies. Initially, a many-to-one X channel is considered and three transmission strategies
are analyzed. The first two strategies are shown to achieve sum-rate capacity
under certain channel conditions. For the third strategy, a sum-rate outer
bound is derived and the gap between the outer bound and the achieved rate is
characterized. These results are later extended to the case. Next,
a region in which the many-to-one X channel can be operated as a many-to-one IC
without loss of sum-rate is identified. Further, in the above region, it is
shown that using Gaussian codebooks and treating interference as noise achieves
a rate point that is within bits from the sum-rate capacity.
Subsequently, some implications of the above results to the Gaussian
many-to-one IC are discussed. Transmission strategies for the many-to-one IC
are formulated and channel conditions under which the strategies achieve
sum-rate capacity are obtained. A region where the sum-rate capacity can be
characterized to within bits is also identified.Comment: Submitted to IEEE Transactions on Information Theory; Revised and
updated version of the original draf
Vegetation hot spot signatures from synergy of DSCOVR EPIC, Terra MISR, MODIS and geostationary sensors
It has been widely recognized that the hotspot region in Bidirectional Reflectance Factors (BRF) of vegetated surfaces represents the most information-rich directions in the directional distribution of canopy reflected radiation. The hotspot effect is strongly correlated with canopy architectural parameters such as foliage size and shape, crown geometry and within-crown foliage arrangement, leaf area index and its sunlit fraction. Here we present a new methodology that synergistically incorporate features of Terra Multi-angle Imaging SpectroRadiometer (MISR) and Moderate Resolution Imaging Spectroradiometer (MODIS), Aqua MODIS, Earth Polychromatic Imaging Camera (EPIC) onboard the Deep Space Climate Observatory (DSCOVR), Advanced Baseline Imager (ABI) carried by the Geostationary Operational Environmental Satellites (GOES) R series and Advanced Himawari Imager (AHI) observation geometries and results in a new type of hot spot signatures that maximally sensitive to vegetation changes. We discuss a physical basis for the synergy of multi-sensor data. Five areas that include Amazonian forests (evergreen broadleaf forest), Mississippi forest (deciduous forest), Heihe River Basin (crops), Genhe forest (coniferous forest) and Australia central grassland were selected to generate time series of hot spot signatures of different land cover types for the period of concurrent Terra/Aqua/DSCOVR and geostationary observations. We demonstrate value of the hot spot signatures for monitoring changes and biophysical processes in vegetated land through analyses of variations in magnitude and shape of angular distribution of canopy reflected radiation and the rigorous use of radiative transfer theory.Accepted manuscrip
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