9,472 research outputs found
ISOGAL Survey of Baade's Windows in the Mid-infrared
The ISOGAL mid-infrared survey of areas close to the Galactic Plane aims to
determine their stellar content and its possible bearing on the history of the
Galaxy. The NGC6522 and Sgr I Baade's Windows of low obscuration towards the
inner parts of the Bulge represent ideal places in which to calibrate and
understand the ISOGAL colour-magnitude diagrams.
The survey observations were made with the ISOCAM instrument of the ISO
satellite. The filter bands chosen were LW2(~7 microns) and LW3(~15 microns).
The results presented here show that most of the detected objects are late
M-type giants on the AGB, with a cut-off for those earlier than M3-M4. The most
luminous members of these two Bulge fields at 7 microns are the Mira variables.
However, it is evident that they represent the end of a sequence of increasing
15 micron dust emission which commences with M giants of earlier sub-type.
In observations of late-type giants the ISOCAM 15 micron band is mainly
sensitive to the cool silicate or aluminate dust shells which overwhelm the
photospheric emission. However, in ordinary M-giant stars, the 7 micron band is
not strongly affected by dust emission and may be influenced instead by
absorption. The nu2 band of water at 6.25 microns and the SiO fundamental at
7.9 microns are likely contribitors to this effect.
A group of late M stars has been found which vary little or not at all but
have infrared colours typical of well-developed dust shells. Their luminosities
are similar to those of 200-300 day Miras but they have slightly redder
[7]-[15] colours which form an extension of the ordinary M giant sequence.
The Mira dust shells show a mid-infrared [7]-[15] colour-period relation. ca
700 days.Comment: 13 pages 15 figure
Diffraction-Limited Imaging and Photometry of NGC 1068
The nearby Seyfert 2 Galaxy NGC 1068 was observed with speckle imaging
techniques in the near-infrared H-band (1.6 microns) at the Hale 200-inch
Telescope and K-band (2.2 microns) at the 10 m Keck I Telescope.
Images with diffraction limited or near-diffraction limited resolutions of
0.''05 - 0.''1 were obtained and used to search for structure in the nuclear
region. Images of the nucleus of NGC 1068 reveal an extended region of emission
which accounts for nearly 50% of the nuclear flux at K-band. This region
extends 10 pc on either side of an unresolved point source nucleus which is at
most, 0.''02 or 1.4 pc in size. Both the point source and the newly imaged
extended emission are very red, with identical H-K colors corresponding to a
color temperature of 800 K. While the point source is of a size to be
consistent with grains in thermal equilibrium with the nuclear source, the
extended emission is not. It must consist either of nuclear emission which has
been reflected off an extended dusty disk or of small grains raised to
transiently high temperatures by reflected UV photons.Comment: accepted to AJ, AAS LaTeX and epsfig, 22 pages incl. 5 ps figure
Projectile Excitations in Reactions
It has recently been proven from measurements of the spin-transfer
coefficients and that there is a small but non-vanishing
component , in the inclusive reaction
cross section . It is shown that the dominant part of the measured
can be explained in terms of the projectile excitation
mechanism. An estimate is further made of contributions to from
s-wave rescattering process. It is found that s-wave rescattering contribution
is much smaller than the contribution coming from projectile
excitation mechanism. The addition of s-wave rescattering contribution to the
dominant part, however, improves the fit to the data.Comment: 9 pages, Revtex, figures can be obtained upon reques
Transforming Sustainable Value in the Construction Industry – The role of Social Movements
Projects pursuing the balance of economic, ecological, and social aspects are being increasingly implemented by the construction industry. This shift represents a paradigm change and evidences new values being acknowledged within the sector. Concurrently, construction scholars tend to emphasize the creation, retention and addition of value, focusing mostly on costs and client deliverables. However, less attention is paid to the process of value change, specifically one that focuses on alternative stakeholders, such as Social Movements. We employ Social Movement theory to comprehend how these organizations affect the notion of value and value change in this industry. Their role is accentuated as a source for a value paradigm change in the form of institutional pressures that shape the values of other stakeholders of the construction industry. These pressures elicit a response in the form of a broader incorporation of sustainable practices amongst construction projects, which effectively alters the industry’s notion of value. Additionally, we showcase a theoretical model that describes the pressure channels originated by Social Movements and their process mechanism affecting the construction industry
Noise Effects on the Complex Patterns of Abnormal Heartbeats
Patients at high risk for sudden death often exhibit complex heart rhythms in
which abnormal heartbeats are interspersed with normal heartbeats. We analyze
such a complex rhythm in a single patient over a 12-hour period and show that
the rhythm can be described by a theoretical model consisting of two
interacting oscillators with stochastic elements. By varying the magnitude of
the noise, we show that for an intermediate level of noise, the model gives
best agreement with key statistical features of the dynamics.Comment: 4 pages, 4 figures, RevTe
Schwarzschild Atmospheric Processes: A Classical Path to the Quantum
We develop some classical descriptions for processes in the Schwarzschild
string atmosphere. These processes suggest relationships between macroscopic
and microscopic scales. The classical descriptions developed in this essay
highlight the fundamental quantum nature of the Schwarzschild atmospheric
processes.Comment: to appear in Gen. Rel. Gra
As indicações geográficas como estratégia mercadológica para vinhos.
Este texto tem como objetivo principal analisar, em termos de estratégia mercadológica, as indicações geográficas (IGs) como instrumento de agregação de valor para o agronegócio brasileiro. Além de analisar a evolução do conceito de indicações geográficas no Brasil, na França e em outros países, este trabalho discute os aspectos mercadológicos desse mecanismo da propriedade intelectual. A fim de ilustrar e sustentar a discussão, apresentam-se os resultados de um estudo das IGs, levando-se em conta a percepção das vinícolas brasileiras e de um nicho do mercado consumidor de vinhos do Distrito Federal, Brasil. Neste estudo, foi observado que as IGs são um fator de diferenciação mercadológica nesse nicho de mercado e, também, uma característica relevante que agrega valor aos vinho s. No mínimo 57% dos consumidores pesquisados estariam dispostos a pagar mais por vinhos que possuíssem uma IG. Por sua vez, as vinícolas brasileiras estão cientes da importância mercadológica das IGs, já que 83% das empresas pesquisadas têm tomado iniciativa com esse propósito. Exceto em alguns casos, observou-se o quão distintas são as percepções dos atores da cadeia pesquisada em relação aos fatores mercadológicos estudados, principalmente sobre a IG. Por fim, são tecidas considerações a respeito das indicações geográficas como uma oportunidade de agregação de valor para o agronegócio brasileiro, sugerindo-se que a construção de uma estratégia mercadológica baseada nas indicações geográficas, tendo como público-alvo consumidores que buscam qualidade superior, pode ser comercialmente positiva para determinados produtores e regiões do agronegócio nacional
Research on nonlinear optical materials: an assessment. IV. Photorefractive and liquid crystal materials
This panel considered two separate subject areas: photorefractive materials used for nonlinear optics and liquid crystal materials used in light valves. Two related subjects were not considered due to lack of expertise on the panel: photorefractive materials used in light valves and liquid crystal materials used in nonlinear optics. Although the inclusion of a discussion of light valves by a panel on nonlinear optical materials at first seems odd, it is logical because light valves and photorefractive materials perform common functions
Massive Stars in the Quintuplet Cluster
We present near-infrared photometry and K-band spectra of newly-identified
massive stars in the Quintuplet Cluster, one of the three massive clusters
projected within 50 pc of the Galactic Center. We find that the cluster
contains a variety of massive stars, including more unambiguously identified
Wolf-Rayet stars than any cluster in the Galaxy, and over a dozen stars in
earlier stages of evolution, i.e., LBV, Ofpe/WN9, and OB supergiants. One newly
identified star is the second ``Luminous Blue Variable'' in the cluster, after
the ``Pistol Star.'' Given the evolutionary stages of the identified stars, the
cluster appears to be about 4 \pm 1 Myr old, assuming coeval formation. The
total mass in observed stars is \sim 10^3 \Msun, and the implied mass is
\sim 10^4 \Msun, assuming a lower mass cutoff of 1 \Msun and a Salpeter
initial mass function. The implied mass density in stars is at least a few
thousand \Msun pc^{-3}. The newly-identified stars increase the estimated
ionizing flux from this cluster by about an order of magnitude with respect to
earlier estimates, to 10^{50.9} photons/s, or roughly what is required to
ionize the nearby ``Sickle'' HII region (G0.18 - 0.04). The total luminosity
from the massive cluster stars is \Lsun, enough to account
for the heating of the nearby molecular cloud, M0.20 - 0.033. We propose a
picture which integrates most of the major features in this part of the sky,
excepting the non-thermal filaments. We compare the cluster to other young
massive clusters and globular clusters, finding that it is unique in stellar
content and age, except, perhaps, for the young cluster in the central parsec
of the Galaxy. In addition, we find that the cluster is comparable to small
``super star clusters.'
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