5,151 research outputs found
The association among diet, dietary fiber, and bowel preparation at colonoscopy
BACKGROUND AND AIMS: Pre-colonoscopy dietary restrictions vary widely and lack evidence-based guidance. We investigated whether fiber and various other foods/macronutrients consumed during the 3 days before colonoscopy are associated with bowel preparation quality.
METHODS: This was a prospective observational study among patients scheduled for outpatient colonoscopy. Patients received instructions including split-dose polyethylene glycol, avoidance of vegetables/beans 2 days before colonoscopy, and a clear liquid diet the day before colonoscopy. Two 24-hour dietary recall interviews and 1 patient-recorded food log measured dietary intake on the 3 days before colonoscopy. The Nutrition Data System for Research was used to estimate dietary exposures. Our primary outcome was the quality of bowel preparation measured by the Boston Bowel Preparation Scale (BBPS).
RESULTS: We enrolled 201 patients from November 2015 to September 2016 with complete data for 168. The mean age was 59 years (standard deviation, 7 years), and 90% of colonoscopies were conducted for screening/surveillance. Only 17% and 77% of patients complied with diet restrictions 2 and 1 day(s) before colonoscopy, respectively. We found no association between foods consumed 2 and 3 days before colonoscopy and BBPS scores. However, BPPS was positively associated with intake of gelatin, and inversely associated with intake of red meat, poultry, and vegetables on the day before colonoscopy.
CONCLUSIONS: Our findings support recent guidelines encouraging unrestricted diets >1 day before colonoscopy if using a split-dose bowel regimen. Furthermore, we found no evidence to restrict dietary fiber 1 day before colonoscopy. We also found evidence to promote consumption of gelatin and avoidance of red meat, poultry, and vegetables 1 day before colonoscopy.Dr Jacobson has acted as a consultant for MOTUS GI and Remedy Partners. All other authors disclosed no financial relationships relevant to this publication. Supported by NIH/NIDDK R21DK105476. (R21DK105476 - NIH/NIDDK)Accepted manuscrip
System model development for nuclear thermal propulsion
A critical enabling technology in the evolutionary development of nuclear thermal propulsion (NTP) is the ability to predict the system performance under a variety of operating conditions. This is crucial for mission analysis and for control subsystem testing as well as for the modeling of various failure modes. Performance must be accurately predicted during steady-state and transient operation, including startup, shutdown, and post operation cooling. The development and application of verified and validated system models has the potential to reduce the design, testing, and cost and time required for the technology to reach flight-ready status. Since Oct. 1991, the U.S. Department of Energy (DOE), Department of Defense (DOD), and NASA have initiated critical technology development efforts for NTP systems to be used on Space Exploration Initiative (SEI) missions to the Moon and Mars. This paper presents the strategy and progress of an interagency NASA/DOE/DOD team for NTP system modeling. It is the intent of the interagency team to develop several levels of computer programs to simulate various NTP systems. The first level will provide rapid, parameterized calculations of overall system performance. Succeeding computer programs will provide analysis of each component in sufficient detail to guide the design teams and experimental efforts. The computer programs will allow simulation of the entire system to allow prediction of the integrated performance. An interagency team was formed for this task to use the best capabilities available and to assure appropriate peer review
Hyperadrenocorticism of calorie restriction contributes to its anti‐inflammatory action in mice
Starbursts versus Truncated Star Formation in Nearby Clusters of Galaxies
We present long-slit spectroscopy, B and R bandpass imaging, and 21 cm
observations of a sample of early-type galaxies in nearby clusters which are
known to be either in a star-forming phase or to have had star formation which
recently terminated. From the long-slit spectra, obtained with the Blanco 4-m
telescope, we find that emission lines in the star-forming cluster galaxies are
significantly more centrally concentrated than in a sample of field galaxies.
The broadband imaging reveals that two currently star-forming early-type
galaxies in the Pegasus I cluster have blue nuclei, again indicating that
recent star formation has been concentrated. In contrast, the two galaxies for
which star formation has already ended show no central color gradient. The
Pegasus I galaxy with the most evident signs of ongoing star formation
(NGC7648), exhibits signatures of a tidal encounter. Neutral hydrogen
observations of that galaxy with the Arecibo radiotelescope reveal the presence
of ~4 x 10^8 solar masses of HI. Arecibo observations of other current or
recent star-forming early-type galaxies in Pegasus I indicate smaller amounts
of gas in one of them, and only upper limits in others.Comment: to be published in Astronomical Journa
Importance of Tests for the Complete Lorentz Structure of the t --> W+ b vertex at Hadron Colliders
The most general Lorentz-invariant decay-density-matrix for , or for , is expressed in terms
of eight helicity parameters. The parameters are physically defined in terms of
partial-width-intensities for polarized-final-states in decay.
The parameters are the partial width, the quark's chirality parameter
, the polarimetry parameter , a "pre-SSB" test parameter
, and four - interference parameters , ,
, which test for violation. They can be
used to test for non-CKM-type CP violation, anomalous 's, top
weak magnetism, weak electricity, and second-class currents. By stage-two
spin-correlation techniques, percent level statistical uncertainites are
typical for measurements at the Tevatron, and several mill level uncertainites
are typical at the LHC.Comment: Minor clarifications. Expression for r_{+-} corrected. 19 pages LaTex
+ Tables + 1 Figur
On the Correlation of Torque and Luminosity in GX 1+4
Over five years of daily hard X-ray (>20 keV) monitoring of the 2-min
accretion-powered pulsar GX 1+4 with the Compton Gamma Ray Observatory/BATSE
large-area detectors has found nearly continuous rapid spin-down, interrupted
by a bright 200-d spin-up episode. During spin-down, the torque becomes more
negative as the luminosity increases (assuming that the 20-60 keV pulsed flux
traces bolometric luminosity), the opposite of what is predicted by standard
accretion torque theory. No changes in the shape of the 20-100 keV pulsed
energy spectrum were detected, so that a very drastic change in the spectrum
below 20 keV or the pulsed fraction would be required to make the 20-60 keV
pulsed flux a poor luminosity tracer. These are the first observations which
flatly contradict standard magnetic disk accretion theory, and they may have
important implications for understanding the spin evolution of X-ray binaries,
cataclysmic variables, and protostars. We briefly discuss the possibility that
GX 1+4 may be accreting from a retrograde disk during spin-down, as previously
suggested.Comment: 10 pages including 3 PS figures. To appear in ApJ Letter
Note on paramoudra-like carbonate concretions in the Urenui Formation, North Taranaki: possible plumbing system for a Late Miocene methane seep field
A reconnaissance study of calcitic and dolomitic tubular concretions in upper slope mudstone of the Late Miocene Urenui Formation exposed along the north Taranaki coastline indicates that they have a complex diagenetic history involving different phases of carbonate cementation and likely hydrofracturing associated with build up of fluid/gas pressures. The concretions resemble classical paramoudra in the European chalk, but are not siliceous and do not have a trace fossil origin. Stable oxygen and carbon isotope data suggest that the micritic carbonate cements in the Urenui paramoudra were probably sourced primarily from ascending methane fluid/gases, and that they precipitated entirely within the host mudstone below the seafloor. We suggest the paramoudra may mark the subsurface plumbing networks of a Late Miocene cold seep system, in which case they have relevance to the evolution and migration of hydrocarbons in Taranaki Basin, at this site perhaps focussed along the Taranaki Fault. The presence of dislodged and mass-emplaced paramoudra in the axial conglomerate of channels within the Urenui mudstone suggests there could be a connection between the loci of seep field development and slope failure and canyon cutting on the Late Miocene Taranaki margin
Realization of a system with metastable states of a capacitively-shunted fluxonium
We realize a system in a superconducting circuit, with metastable
states exhibiting lifetimes up to 8\,ms. We exponentially suppress the
tunneling matrix elements involved in spontaneous energy relaxation by creating
a "heavy" fluxonium, realized by adding a capacitive shunt to the original
circuit design. The device allows for both cavity-assisted and direct
fluorescent readout, as well as state preparation schemes akin to optical
pumping. Since direct transitions between the metastable states are strongly
suppressed, we utilize Raman transitions for coherent manipulation of the
states.Comment: Total of 10 pages. 5 pages in main tex, and 5 in supplement. Total of
9 figures in entire documen
A Nova Outburst Powered by Shocks
Classical novae are runaway thermonuclear burning events on the surfaces of
accreting white dwarfs in close binary star systems, sometimes appearing as new
naked-eye sources in the night sky. The standard model of novae predicts that
their optical luminosity derives from energy released near the hot white dwarf
which is reprocessed through the ejected material. Recent studies with the
Fermi Large Area Telescope have shown that many classical novae are accompanied
by gigaelectronvolt gamma-ray emission. This emission likely originates from
strong shocks, providing new insights into the properties of nova outflows and
allowing them to be used as laboratories to study the unknown efficiency of
particle acceleration in shocks. Here we report gamma-ray and optical
observations of the Milky Way nova ASASSN-16ma, which is among the brightest
novae ever detected in gamma-rays. The gamma-ray and optical light curves show
a remarkable correlation, implying that the majority of the optical light comes
from reprocessed emission from shocks rather than the white dwarf. The ratio of
gamma-ray to optical flux in ASASSN-16ma directly constrains the acceleration
efficiency of non-thermal particles to be ~0.005, favouring hadronic models for
the gamma-ray emission. The need to accelerate particles up to energies
exceeding 100 gigaelectronvolts provides compelling evidence for magnetic field
amplification in the shocks.Comment: Published in Nature Astronomy. This is the authors' version with 55
pages, 8 figures, and 3 table
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