3,690 research outputs found
Open Space – a collaborative process for facilitating Tourism IT partnerships
The success of IT projects depends on the success of the partnerships on which they are based. However past research by the author has identified a significant rate of failure in these partnerships, predominantly due to an overly technical mindset, leading to the question: “how do we ensure that, as technological solutions are implemented within tourism, due consideration is given to human-centred issues?” The tourism partnership literature is explored for additional insights revealing that issues connected with power, participation and normative positions play a major role. The method, Open Space, is investigated for its ability to engage stakeholders in free and open debate. This paper reports on a one-day Open Space event sponsored by two major intermediaries in the UK travel industry who wanted to consult their business partners. Both the running of the event and its results reveal how Open Space has the potential to address some of the weaknesses associated with tourism partnerships
The 2011 Workplace Employment Relations Study: first findings
The 2011 Workplace Employment Relations Study (WERS) is the sixth survey of employment relations in Britain. It collected data from a representative sample of 2,680 British workplaces, from: 2,680 workplace managers responsible for employment relations and personnel 1,002 worker representatives 21,981 employee
Detection of gravity modes in the massive binary V380 Cyg from Kepler spacebased photometry and high-resolution spectroscopy
We report the discovery of low-amplitude gravity-mode oscillations in the
massive binary star V380 Cyg, from 180 d of Kepler custom-aperture space
photometry and 5 months of high-resolution high signal-to-noise spectroscopy.
The new data are of unprecedented quality and allowed to improve the orbital
and fundamental parameters for this binary. The orbital solution was subtracted
from the photometric data and led to the detection of periodic intrinsic
variability with frequencies of which some are multiples of the orbital
frequency and others are not. Spectral disentangling allowed the detection of
line-profile variability in the primary. With our discovery of intrinsic
variability interpreted as gravity mode oscillations, V380 Cyg becomes an
important laboratory for future seismic tuning of the near-core physics in
massive B-type stars.Comment: 5 pages, 4 figures, 2 tables. Accepted for publication in MNRAS
Letter
Initial Characteristics of Kepler Short Cadence Data
The Kepler Mission offers two options for observations -- either Long Cadence
(LC) used for the bulk of core mission science, or Short Cadence (SC) which is
used for applications such as asteroseismology of solar-like stars and transit
timing measurements of exoplanets where the 1-minute sampling is critical. We
discuss the characteristics of SC data obtained in the 33.5-day long Quarter 1
(Q1) observations with Kepler which completed on 15 June 2009. The truly
excellent time series precisions are nearly Poisson limited at 11th magnitude
providing per-point measurement errors of 200 parts-per-million per minute. For
extremely saturated stars near 7th magnitude precisions of 40 ppm are reached,
while for background limited measurements at 17th magnitude precisions of 7
mmag are maintained. We note the presence of two additive artifacts, one that
generates regularly spaced peaks in frequency, and one that involves additive
offsets in the time domain inversely proportional to stellar brightness. The
difference between LC and SC sampling is illustrated for transit observations
of TrES-2.Comment: 5 pages, 4 figures, ApJ Letters in pres
Fast Ensemble Smoothing
Smoothing is essential to many oceanographic, meteorological and hydrological
applications. The interval smoothing problem updates all desired states within
a time interval using all available observations. The fixed-lag smoothing
problem updates only a fixed number of states prior to the observation at
current time. The fixed-lag smoothing problem is, in general, thought to be
computationally faster than a fixed-interval smoother, and can be an
appropriate approximation for long interval-smoothing problems. In this paper,
we use an ensemble-based approach to fixed-interval and fixed-lag smoothing,
and synthesize two algorithms. The first algorithm produces a linear time
solution to the interval smoothing problem with a fixed factor, and the second
one produces a fixed-lag solution that is independent of the lag length.
Identical-twin experiments conducted with the Lorenz-95 model show that for lag
lengths approximately equal to the error doubling time, or for long intervals
the proposed methods can provide significant computational savings. These
results suggest that ensemble methods yield both fixed-interval and fixed-lag
smoothing solutions that cost little additional effort over filtering and model
propagation, in the sense that in practical ensemble application the additional
increment is a small fraction of either filtering or model propagation costs.
We also show that fixed-interval smoothing can perform as fast as fixed-lag
smoothing and may be advantageous when memory is not an issue
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Predictive impact of rare genomic copy number variations in siblings of individuals with autism spectrum disorders.
Identification of genetic biomarkers associated with autism spectrum disorders (ASDs) could improve recurrence prediction for families with a child with ASD. Here, we describe clinical microarray findings for 253 longitudinally phenotyped ASD families from the Baby Siblings Research Consortium (BSRC), encompassing 288 infant siblings. By age 3, 103 siblings (35.8%) were diagnosed with ASD and 54 (18.8%) were developing atypically. Thirteen siblings have copy number variants (CNVs) involving ASD-relevant genes: 6 with ASD, 5 atypically developing, and 2 typically developing. Within these families, an ASD-related CNV in a sibling has a positive predictive value (PPV) for ASD or atypical development of 0.83; the Simons Simplex Collection of ASD families shows similar PPVs. Polygenic risk analyses suggest that common genetic variants may also contribute to ASD. CNV findings would have been pre-symptomatically predictive of ASD or atypical development in 11 (7%) of the 157 BSRC siblings who were eventually diagnosed clinically
Dynamical masses, absolute radii and 3D orbits of the triply eclipsing star HD 181068 from Kepler photometry
HD 181068 is the brighter of the two known triply eclipsing hierarchical triple stars in the
Kepler field. It has been continuously observed for more than 2 yr with the Kepler space
telescope. Of the nine quarters of the data, three have been obtained in short-cadence mode,
that is one point per 58.9 s. Here we analyse this unique data set to determine absolute physical
parameters (most importantly the masses and radii) and full orbital configuration using a
sophisticated novel approach. We measure eclipse timing variations (ETVs), which are then
combined with the single-lined radial velocity measurements to yield masses in a manner
equivalent to double-lined spectroscopic binaries. We have also developed a new light-curve
synthesis code that is used to model the triple, mutual eclipses and the effects of the changing
tidal field on the stellar surface and the relativistic Doppler beaming. By combining the stellar
masses from the ETV study with the simultaneous light-curve analysis we determine the
absolute radii of the three stars. Our results indicate that the close and the wide subsystems
revolve in almost exactly coplanar and prograde orbits. The newly determined parameters
draw a consistent picture of the system with such details that have been beyond reach before
Low False-Positive Rate of Kepler Candidates Estimated From A Combination Of Spitzer And Follow-Up Observations
(Abridged) NASA's Kepler mission has provided several thousand transiting
planet candidates, yet only a small subset have been confirmed as true planets.
Therefore, the most fundamental question about these candidates is the fraction
of bona fide planets. Estimating the rate of false positives of the overall
Kepler sample is necessary to derive the planet occurrence rate. We present the
results from two large observational campaigns that were conducted with the
Spitzer telescope during the the Kepler mission. These observations are
dedicated to estimating the false positive rate (FPR) amongst the Kepler
candidates. We select a sub-sample of 51 candidates, spanning wide ranges in
stellar, orbital and planetary parameter space, and we observe their transits
with Spitzer at 4.5 microns. We use these observations to measures the
candidate's transit depths and infrared magnitudes. A bandpass-dependent depth
alerts us to the potential presence of a blending star that could be the source
of the observed eclipse: a false-positive scenario. For most of the candidates
(85%), the transit depths measured with Kepler are consistent with the depths
measured with Spitzer as expected for planetary objects, while we find that the
most discrepant measurements are due to the presence of unresolved stars that
dilute the photometry. The Spitzer constraints on their own yield FPRs between
5-40%, depending on the KOIs. By considering the population of the Kepler field
stars, and by combining follow-up observations (imaging) when available, we
find that the overall FPR of our sample is low. The measured upper limit on the
FPR of our sample is 8.8% at a confidence level of 3 sigma. This observational
result, which uses the achromatic property of planetary transit signals that is
not investigated by the Kepler observations, provides an independent indication
that Kepler's false positive rate is low.Comment: 33 pages, 16 figures, 3 tables; accepted for publication in ApJ on
February 7, 201
Benefits Analysis of Wind-Optimal Operations For Trans-Atlantic Flights
North Atlantic Tracks are trans-Atlantic routes across the busiest oceanic airspace in the world. This study analyzes and compares current flight-plan routes to wind-optimal routes for trans-Atlantic flights in terms of aircraft fuel burn, emissions and the associated climate impact. The historical flight track data recorded by EUROCONTROL's Central Flow Management Unit is merged with data from FAA's Enhanced Traffic Management System to provide an accurate flight movement database containing the highest available flight path resolution in both systems. The combined database is adopted for airspace simulation integrated with aircraft fuel burn and emissions models, contrail models, simplified climate response models, and a common climate metric to assess the climate impact of flight routes within the Organized Track System (OTS). The fuel burn and emissions for the tracks in the OTS are compared with the corresponding quantities for the wind-optimized routes to evaluate the potential environmental benefits of flying wind-optimal routes in North Atlantic Airspace. The potential fuel savings and reduction in emissions depend on existing inefficiencies in current flight plans, atmospheric conditions and location of the city-pairs. The potential benefits are scaled by comparing them with actual flight tests that have been conducted since 2010 between a few city-pairs in the transatlantic and trans-pacific region to improve fuel consumption and reduce the environmental impact of aviation
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