9,451 research outputs found
The Value of Terroir: Hedonic Estimation of Vineyard Sale Prices
We examine the value of terroir, which refers to the special characteristics of a place that impart unique qualities to the wine produced. We do this by conducting a hedonic analysis of vineyard sales in the Willamette Valley of Oregon to ascertain whether site attributes, such as slope, aspect, elevation, and soil types, or designated appellations are more important determinants of price. We find that prices are strongly determined by sub-AVA appellation designations, but not by specific site attributes. These results indicate that the concept of terroir matters economically, although the reality of terroir--as proxied for by locational attributes--is not significant.
Dynamics and Steady States in excitable mobile agent systems
We study the spreading of excitations in 2D systems of mobile agents where
the excitation is transmitted when a quiescent agent keeps contact with an
excited one during a non-vanishing time. We show that the steady states
strongly depend on the spatial agent dynamics. Moreover, the coupling between
exposition time () and agent-agent contact rate (CR) becomes crucial to
understand the excitation dynamics, which exhibits three regimes with CR: no
excitation for low CR, an excited regime in which the number of quiescent
agents (S) is inversely proportional to CR, and for high CR, a novel third
regime, model dependent, here S scales with an exponent , with
being the scaling exponent of with CR
Designing novel applications for emerging multimedia technology
Current R&D in media technologies such as Multimedia, Semantic Web and Sensor Web technologies are advancing in a fierce rate and will sure to become part of our important regular items in a 'conventional' technology inventory in near future. While the R&D nature of these technologies means their accuracy, reliability and robustness are not sufficient enough to be used in real world yet, we want to envision now the near-future where these technologies will have matured and used in real applications in order to explore and start shaping many possible new ways these novel technologies could be utilised.
In this talk, some of this effort in designing novel applications that incorporate various media technologies as their backend will be presented. Examples include novel scenarios of LifeLogging application that incorporate automatic structuring of millions of photos passively captured from a SenseCam (wearable digital camera that automatically takes photos triggered by environmental sensors) and an interactive TV application incorporating a number of multimedia tools yet extremely simple and easy to use with a remote control in a lean-back position. The talk will conclude with remarks on how the design of novel applications that have no precedence or existing user base should require somewhat different approach from those suggested and practiced in conventional usability engineering methodology
Exploring the planetary-mass population in the Upper Scorpius association
We aim at identifying very low-mass isolated planetary-mass member candidates
in the nearest OB association to the Sun, Upper Scorpius (145 pc; 5-10 Myr), to
constrain the form and shape of the luminosity function and mass spectrum in
this regime. We conducted a deep multi-band (=21.2, =20.5, =22.0 mag)
photometric survey of six square degrees in the central region of Upper
Scorpius. We extend the current sequence of astrometric and spectroscopic
members by about two magnitudes in and one magnitude in , reaching
potentially T-type free-floating members in the association with predicted
masses below 5 Jupiter masses, well into the planetary-mass regime. We
extracted a sample of 57 candidates in this area and present infrared
spectroscopy confirming two of them as young L-type members with characteristic
spectral features of 10 Myr-old brown dwarfs. Among the 57 candidates, we
highlight 10 new candidates fainter than the coolest members previously
confirmed spectroscopically. We do not see any obvious sign of decrease in the
mass spectrum of the association, suggesting that star processes can form
substellar objects with masses down to 4-5 Jupiter masses.Comment: 14 pages, 8 figures, 3 tables, 1 appendix with 3 tables that will be
public through Vizier at CDS, accepted by MNRA
The WFCAM Multi-wavelength Variable Star Catalog
Stellar variability in the near-infrared (NIR) remains largely unexplored.
The exploitation of public science archives with data-mining methods offers a
perspective for the time-domain exploration of the NIR sky. We perform a
comprehensive search for stellar variability using the optical-NIR multi-band
photometric data in the public Calibration Database of the WFCAM Science
Archive (WSA), with the aim of contributing to the general census of variable
stars, and to extend the current scarce inventory of accurate NIR light curves
for a number of variable star classes. We introduce new variability indices
designed for multi-band data with correlated sampling, and apply them for
pre-selecting variable star candidates, i.e., light curves that are dominated
by correlated variations, from noise-dominated ones. Pre-selection criteria are
established by robust numerical tests for evaluating the response of
variability indices to colored noise characteristic to the data. We find 275
periodic variable stars and an additional 44 objects with suspected variability
with uncertain periods or apparently aperiodic variation. Only 44 of these
objects had been previously known, including 11 RR~Lyrae stars in the outskirts
of the globular cluster M3 (NGC~5272). We provide a preliminary classification
of the new variable stars that have well-measured light curves, but the
variability types of a large number of objects remain ambiguous. We classify
most of the new variables as contact binary stars, but we also find several
pulsating stars, among which 34 are probably new field RR~Lyrae and 3 are
likely Cepheids. We also identify 32 highly reddened variable objects close to
previously known dark nebulae, suggesting that these are embedded young stellar
objects. We publish our results and all light-curve data as the WFCAM Variable
Star Catalog.Comment: 21 pages, 11 figure
- …