35,790 research outputs found
Effective use of ERTS multisensor data in the Northern Great Plains
The author has identified the following significant results. ERTS imagery was used as a tool in the identification and refinement of soil association areas; to classify land use patterns between crop and fallow fields; to identify corn, soybeans, and oats; and to identify broad generalized range ecosystems. Various data handling techniques were developed and applied to accomplish these tasks. A map outlining soil associations and relative land values was completed on a base mosaic of ERTS imagery and is included as an appendix to the report
Observations of Hierarchical Solar-Type Multiple Star Systems
Twenty multiple stellar systems with solar-type primaries were observed at
high angular resolution using the PALM-3000 adaptive optics system at the 5 m
Hale telescope. The goal was to complement the knowledge of hierarchical
multiplicity in the solar neighborhood by confirming recent discoveries by the
visible Robo-AO system with new near-infrared observations with PALM-3000. The
physical status of most, but not all, of the new pairs is confirmed by
photometry in the Ks band and new positional measurements. In addition, we
resolved for the first time five close sub-systems: the known astrometric
binary in HIP 17129AB, companions to the primaries of HIP 33555, and HIP
118213, and the companions to the secondaries in HIP 25300 and HIP 101430. We
place the components on a color-magnitude diagram and discuss each multiple
system individually.Comment: Accepted to Astronomical Journa
Measuring non-extensitivity parameters in a turbulent Couette-Taylor flow
We investigate probability density functions of velocity differences at
different distances r measured in a Couette-Taylor flow for a range of Reynolds
numbers Re. There is good agreement with the predictions of a theoretical model
based on non-extensive statistical mechanics (where the entropies are
non-additive for independent subsystems). We extract the scale-dependent
non-extensitivity parameter q(r, Re) from the laboratory data.Comment: 8 pages, 5 figure
Resummation Effects in Vector-Boson and Higgs Associated Production
Fixed-order QCD radiative corrections to the vector-boson and Higgs
associated production channels, pp -> VH (V=W, Z), at hadron colliders are well
understood. We combine higher order perturbative QCD calculations with
soft-gluon resummation of both threshold logarithms and logarithms which are
important at low transverse momentum of the VH pair. We study the effects of
both types of logarithms on the scale dependence of the total cross section and
on various kinematic distributions. The next-to-next-to-next-to-leading
logarithmic (NNNLL) resummed total cross sections at the LHC are almost
identical to the fixed-order perturbative next-to-next-to-leading order (NNLO)
rates, indicating the excellent convergence of the perturbative QCD series.
Resummation of the VH transverse momentum (p_T) spectrum provides reliable
results for small values of p_T and suggests that implementing a jet-veto will
significantly decrease the cross sections.Comment: 25 pages, references update
Multiwavelength Observations of Swift J1753.5-0127
We present contemporaneous X-ray, ultraviolet, optical and near-infrared
observations of the black hole binary system, Swift J1753.5-0127, acquired in
2012 October. The UV observations, obtained with the Cosmic Origins
Spectrograph on the Hubble Space Telescope, are the first UV spectra of this
system. The dereddened UV spectrum is characterized by a smooth, blue continuum
and broad emission lines of CIV and HeII. The system was stable in the UV to
<10% during our observations. We estimated the interstellar reddening by
fitting the 2175 A absorption feature and fit the interstellar absorption
profile of Ly to directly measure the neutral hydrogen column density
along the line of sight. By comparing the UV continuum flux to steady-state
thin accretion disk models, we determined upper limits on the distance to the
system as a function of black hole mass. The continuum is well fit with disk
models dominated by viscous heating rather than irradiation. The broadband
spectral energy distribution shows the system has declined at all wavelengths
since previous broadband observations in 2005 and 2007. If we assume that the
UV emission is dominated by the accretion disk the inner radius of the disk
must be truncated at radii above the ISCO to be consistent with the X-ray flux,
requiring significant mass loss from outflows and/or energy loss via advection
into the black hole to maintain energy balance.Comment: To appear in the Ap
Online information needs of cancer patients and their organizations
Increasingly patients, relatives and carers are accessing health information via the internet. However, the health profession and people affected by cancer are becoming concerned with the quality of that information. A European survey was conducted under the auspices of the FP7 European Commission funded Eurocancercoms project1 during the period September 2010–March 2011. Its aim was to assess current online information needs of people with cancer particularly those who seek information using online social media technologies and the internet more broadly. A literature review was undertaken to gain a greater understanding of health seeking behaviour regarding cancer patients’ information needs and patient preferences for accessing different formats and media. This was used to inform the design and validation of online pan-European, multi-lingual questionnaires distributed via patient organizations and via specific Eurocancercoms partner organizations. This paper presents the results of this survey and suggests recommendations to be incorporated into the design of the online platform, ecancerHub, one of the intended outcomes of the Eurocancercoms project following this research. People want a wide variety of easy to find, easy to understand accurate information about cancer and how it is likely to impact on their everyday lives and on those close to them. They differ in the amount and detail of the information they would like and on their ability to identify quality information and understand it sufficiently to base their health-care decisions on. The majority of respondents raised the issue of quality of information and many requested recommendations of websites by the people who usually influence them most, the health professionals involved in their care
Know the Star, Know the Planet. III. Discovery of Late-Type Companions to Two Exoplanet Host Stars
We discuss two multiple star systems that host known exoplanets: HD 2638 and
30 Ari B. Adaptive optics imagery revealed an additional stellar companion to
both stars. We collected multi-epoch images of the systems with Robo-AO and the
PALM-3000 adaptive optics systems at Palomar Observatory and provide relative
photometry and astrometry. The astrometry indicates that the companions share
common proper motion with their respective primaries. Both of the new
companions have projected separations less than 30 AU from the exoplanet host
star. Using the projected separations to compute orbital periods of the new
stellar companions, HD 2638 has a period of 130 yrs and 30 Ari B has a period
of 80 years. Previous studies have shown that the true period is most likely
within a factor of three of these estimated values. The additional component to
the 30 Ari makes it the second confirmed quadruple system known to host an
exoplanet. HD 2638 hosts a hot Jupiter and the discovery of a new companion
strengthens the connection between hot Jupiters and binary stars. We place the
systems on a color-magnitude diagram and derive masses for the companions which
turn out to be roughly 0.5 solar mass stars.Comment: Accepted to Astronomical Journal, 16 pages, 5 Figure
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