2,836 research outputs found
Recommended from our members
Effective Temperature Of Uranus
NASA NGR 09-015-047, NGR 22-007-270, NGR 44-012-152Astronom
Regret Aversion and False Reference Points in Residential Real Estate
This study empirically exams the combination of regret aversion and false reference points in a residential real estate context. Survey respondents were put in a hypothetical situation, where they had purchased an investment property several years ago. Hindsight knowledge about a foregone all time high was introduced. As hypothesized, respondents on average expressed higher regret if they had actively failed to sell at the all time high (commission scenario) than if they had simply been unaware of the potential gain (omission scenario). Women were found to be more susceptible to regret aversion and false reference points than men.
Atmospheric Biomarkers and their Evolution over Geological Timescales
The search for life on extrasolar planets is based on the assumption that one
can screen extrasolar planets for habitability spectroscopically. The first
space born instruments able to detect as well as characterize extrasolar
planets, Darwin and terrestrial planet finder (TPF-I and TPF-C) are scheduled
to launch before the end of the next decade. The composition of the planetary
surface, atmosphere, and its temperature-pressure profile influence a
detectable spectroscopic signal considerably. For future space-based missions
it will be crucial to know this influence to interpret the observed signals and
detect signatures of life in remotely observed atmospheres. We give an overview
of biomarkers in the visible and IR range, corresponding to the TPF-C and
TPF-I/DARWIN concepts, respectively. We also give an overview of the evolution
of biomarkers over time and its implication for the search for life on
extrasolar Earth-like planets. We show that atmospheric features on Earth can
provide clues of biological activities for at least 2 billion years.Comment: for high resolution images see
http://cfa-www.harvard.edu/~lkaltenegge
Dynamically-Coupled Oscillators -- Cooperative Behavior via Dynamical Interaction --
We propose a theoretical framework to study the cooperative behavior of
dynamically coupled oscillators (DCOs) that possess dynamical interactions.
Then, to understand synchronization phenomena in networks of interneurons which
possess inhibitory interactions, we propose a DCO model with dynamics of
interactions that tend to cause 180-degree phase lags. Employing an approach
developed here, we demonstrate that although our model displays synchronization
at high frequencies, it does not exhibit synchronization at low frequencies
because this dynamical interaction does not cause a phase lag sufficiently
large to cancel the effect of the inhibition. We interpret the disappearance of
synchronization in our model with decreasing frequency as describing the
breakdown of synchronization in the interneuron network of the CA1 area below
the critical frequency of 20 Hz.Comment: 10 pages, 3 figure
The A20 Protein Interacts with the EpsteinâBarr Virus Latent Membrane Protein 1 (LMP1) and Alters the LMP1/TRAF1/TRADD Complex
The Epstein-Barr virus (EBV) latent membrane protein 1 (LMP1) interacts with the tumor necrosis factor receptor (TNFR)-associated factor (TRAF) molecules, which are important for LMP1-mediated signaling. Two domains of LMP1 can independently activate NF-kB, carboxyl-terminal activating region 1 (CTAR1) and CTAR2. The activation of NF-kB by CTAR1 occurs through direct interaction of LMP1 with the TRAF molecules, whereas CTAR2 interacts with the TNFR-associated death domain protein (TRADD) to activate NF-kB and the c-Jun N-terminal kinase (JNK). A20, which is induced by LMP1 through NF-kB, can block NF-kB activation from both domains of LMP1 and inhibit JNK activation from CTAR2. A20 also has been shown to associate with TRAF1 and TRAF2. In this study, an interaction between LMP1 and A20 was detected that was increased by TRAF2 overexpression. A20 did not affect the association of TRAF1 with TRAF2 but did displace TRAF1 from the LMP1 complex. The interaction of LMP1 and TRADD was decreased in the presence of A20, and the LMP1-A20 association was decreased by TRADD, suggesting that A20 and TRADD both interact with LMP1 and may compete for binding. These data indicate that A20 alters the interactions between LMP1 and the TRAF molecules and TRADD, affecting the activation of NF-kB, JNK, and perhaps other TRAF-mediated signaling events
First Keck Nulling Observations of a Young Stellar Object: Probing the Circumstellar Environment of the Herbig Ae star MWC 325
We present the first N-band nulling plus K- and L-band V2 observations of a
young stellar object, MWC325, taken with the 85 m baseline Keck Interferometer.
The Keck nuller was designed for the study of faint dust signatures associated
with debris disks, but it also has a unique capability for studying the
temperature and density distribution of denser disks found around young stellar
objects. Interferometric observations of MWC 325 at K, L and N encompass a
factor of five in spectral range and thus, especially when spectrally dispersed
within each band, enable characterization of the structure of the inner disk
regions where planets form. Fitting our observations with geometric models such
as a uniform disk or a Gaussian disk show that the apparent size increases
monotonically with wavelength in the 2-12 um wavelength region, confirming the
widely held assumption based on radiative transfer models, now with spatially
resolved measurements over broad wavelength range, that disks are extended with
a temperature gradient. The effective size is a factor of about 1.3 and 2
larger in the L-band and N-band, respectively, compared to that in the K-band.
The existing interferometric measurements and the spectral energy distribution
can be reproduced by a flat disk or a weakly-shadowed nearly flat-disk model,
with only slight flaring in the outer regions of the disk, consisting of
representative "sub-micron" (0.1 um) and "micron" (2 um) grains of a 50:50
ratio of silicate and graphite. This is marked contrast with the disks
previously found in other Herbig Ae/Be stars suggesting a wide variety in the
disk properties among Herbig Ae/Be stars.Comment: Accepted for publication in the Ap
Impact Analysis of OCR Quality on Research Tasks in Digital Archives
Humanities scholars increasingly rely on digital archives for their research in place of time-consuming visits to physical archives. This shift in research methodology has the hidden cost of working with digi- tally processed historical documents: how much trust can a scholar place in noisy representations of source texts? In a series of interviews with historians about their use of digital archives, we found that scholars are aware that optical character recognition (OCR) errors may bias their results. They were, however, unable to quantify this bias or to indicate what information they would need to estimate it. Based on the interviews and a literature study, we provide a classification scheme relating schol- arly research tasks to their specific OCR-induced uncertainty and the data required for more reliable uncertainty estimations. We conducted a use case study on a national newspaper archive with example research tasks. From this we learned what data is typically available in digital archives and how it could be used to reduce and/or assess the uncer- tainty in result sets. We conclude that the current knowledge situation on the usersâ side as well as on the tool makers and data providersâ side is insufficient and needs further research to be improved
Second Screen Interactions for Automatically Web-Enriched Broadcast Video
Including hypermedia in broadcast video combines content formatted
for a lean-forward medium (the Web) with a lean-back one (TV) to form a
hybrid medium. We identify four challenges for interacting with and
experiencing this new medium. We discuss the role a second screen may play in
addressing these challenges
The prevalence of visual anomalies among adult offenders
Fifty-three incarcerated adult sexual offenders from a voluntary treatment program at the Oregon State Correctional Facility were screened for visual anomalies. Subjects were divided into two groups based on intellectual function, one a higher functioning (HF) group, and one a social skills (SS) group. The two groups were compared based on a screening battery probing ocular health, eye movement skills, visual perceptual abilities and accommodative/vergence abilities. The ocular health did not differ between the two groups or from the general population. Differences were found in visual perceptual function between the high and low functioning groups. The HF group outperformed the lower on all perceptual and eye movement tests except the subjective eye movement evaluation. Unexpected differences were found between the two groups in the areas of accommodative posture, vergence facility, and distance monocular acuities
Imaging the spotty surface of Betelgeuse in the H band
This paper reports on H-band interferometric observations of Betelgeuse made
at the three-telescope interferometer IOTA. We image Betelgeuse and its
asymmetries to understand the spatial variation of the photosphere, including
its diameter, limb darkening, effective temperature, surrounding brightness,
and bright (or dark) star spots. We used different theoretical simulations of
the photosphere and dusty environment to model the visibility data. We made
images with parametric modeling and two image reconstruction algorithms: MIRA
and WISARD. We measure an average limb-darkened diameter of 44.28 +/- 0.15 mas
with linear and quadratic models and a Rosseland diameter of 45.03 +/- 0.12 mas
with a MARCS model. These measurements lead us to derive an updated effective
temperature of 3600 +/- 66 K. We detect a fully-resolved environment to which
the silicate dust shell is likely to contribute. By using two imaging
reconstruction algorithms, we unveiled two bright spots on the surface of
Betelgeuse. One spot has a diameter of about 11 mas and accounts for about 8.5%
of the total flux. The second one is unresolved (diameter < 9 mas) with 4.5% of
the total flux. Resolved images of Betelgeuse in the H band are asymmetric at
the level of a few percent. The MOLsphere is not detected in this wavelength
range. The amount of measured limb-darkening is in good agreement with model
predictions. The two spots imaged at the surface of the star are potential
signatures of convective cells.Comment: 10 pages, 10 figures, accepted for publication in A&A, references
adde
- âŚ