931 research outputs found
Application of Osteopathic Manipulative Medicine to Ameliorate Sepsis Induced Ileus
Graduate
Basi
The First Three Rungs of the Cosmological Distance Ladder
It is straightforward to determine the size of the Earth and the distance to
the Moon without making use of a telescope. The methods have been known since
the 3rd century BC. However, few amateur or professional astronomers have
worked this out from data they themselves have taken. Here we use a gnomon to
determine the latitude and longitude of South Bend, Indiana, and College
Station, Texas, and determine a value of the radius of the Earth of 6290 km,
only 1.4 percent smaller than the true value. We use the method of Aristarchus
and the size of the Earth's shadow during the lunar eclipse of 2011 June 15 to
derive an estimate of the distance to the Moon (62.3 R_Earth), some 3.3 percent
greater than the true mean value. We use measurements of the angular motion of
the Moon against the background stars over the course of two nights, using a
simple cross staff device, to estimate the Moon's distance at perigee and
apogee. Finally, we use simultaneous CCD observations of asteroid 1996 HW1
obtained with small telescopes in Socorro, New Mexico, and Ojai, California, to
derive a value of the Astronomical Unit of (1.59 +/- 0.19) X 10^8 km, about 6
percent too large. The data and methods presented here can easily become part
of a beginning astronomy lab class.Comment: 34 pages, 11 figures, accepted for publication in American Journal of
Physic
Caltech Faint Galaxy Redshift Survey X: A Redshift Survey in the Region of the Hubble Deep Field North
A redshift survey has been carried out in the region of the Hubble Deep Field
North using the Low Resolution Imaging Spectrograph at the Keck Observatory.
The resulting redshift catalog, which contains 671 entries, is a compendium of
our own data together with published LRIS/Keck data. It is more than 92%
complete for objects, irrespective of morphology, to mag in the HDF
itself and to mag in the Flanking Fields within a diameter of 8 arcmin
centered on the HDF, an unusually high completion for a magnitude limited
survey performed with a large telescope. A median redshift is reached
at .
Strong peaks in the redshift distribution, which arise when a group or poor
cluster of galaxies intersect the area surveyed, can be identified to in this dataset. More than 68% of the galaxies are members of these
redshift peaks. In a few cases, closely spaced peaks in can be resolved
into separate groups of galaxies that can be distinguished in both velocity and
location on the sky.
The radial separation of these peaks in the pencil-beam survey is consistent
with a characteristic length scale for the their separation of 70 Mpc
in our adopted cosmology (, ). Strong
galaxy clustering is in evidence at all epochs back to . (abstract
abridged)Comment: Accepted to the ApJ. This version contains all the figures and
tables. 2 minor typos in table 2b correcte
Long-term outcome after early infrainguinal graft failure
AbstractPurpose: To determine the long-term outcome and prognostic factors after early infrainguinal graft failure (<30 days).Methods: Retrospective analysis of limb salvage data, patency data, and prognostic risk factors in 112 new infrainguinal bypass grafts from 1985 to 1995 that occluded within 30 days of operation.Result: Thirty-six femoropopliteal and 76 femorotibial/femoropedal arterial bypass (âindexâ) procedures were performed for rest pain (50%), tissue loss (31%), or disabling claudication (19%). In 103 patients, an immediate additional revascularization (âtakebackâ) procedure was performed at the time of early graft failure. Life table analysis of the takeback procedures for threatened limbs (n = 84) revealed limb salvage rates of 74%, 54%, 40%, and 31% at 1 month, 1 year, 3 years, and 5 years, respectively. The 1-month limb salvage rate (threatened limbs) was 12% (1 of 8) in patients who were not taken back for revascularization and 33% (4 of 12) in patients who had undergone more than one takeback procedure within 30 days. The secondary graft patency rates for the takeback procedures (n = 103) were 70%, 37%, 27%, and 23% at 1 month, 1 year, 3 years, and 5 years, respectively. Univariate and life table analysis revealed that patients who were given anticoagulation medication after the index procedure (before graft thrombosis) or patients who had undergone previous ipsilateral leg revascularization had significantly lower rates of limb salvage and graft patency (p < 0.05). The limb salvage rate was also significantly worse in patients who had single-vessel runoff compared with those who had multiple-vessel runoff (p < 0.01). Thrombectomy and revision or complete graft replacement had a better secondary patency rate than thrombectomy alone (p < 0.05). Autogenous vein grafts had better outcome than polytetrafluoroethylene-containing grafts, but statistical significance was not achieved. No significant differences in limb salvage or graft patency rates were found between femoropopliteal versus femorotibial/femoropedal bypass grafting, age, gender, previous inflow surgery, diabetes, hypertension, smoking, or cardiac, renal, or pulmonary disease.Conclusion: The long-term limb salvage and graft patency rates after takeback revascularization procedures for early graft failure are poor. Despite poor outcome, a single takeback procedure appears warranted in all patients. Multiple takeback procedures, however, do not appear to be justified, especially in patients who are given anticoagulation medication after the index bypass procedure, repeat leg bypass procedures, or if there is no potential for graft revision
IR and UV Galaxies at z=0.6 -- Evolution of Dust Attenuation and Stellar Mass as Revealed by SWIRE and GALEX
We study dust attenuation and stellar mass of star-forming
galaxies using new SWIRE observations in IR and GALEX observations in UV. Two
samples are selected from the SWIRE and GALEX source catalogs in the
SWIRE/GALEX field ELAIS-N1-00 ( deg). The UV selected sample
has 600 galaxies with photometric redshift (hereafter photo-z) and NUV (corresponding to \rm L_{FUV} \geq 10^{9.6} L_\sun).
The IR selected sample contains 430 galaxies with mJy
(\rm L_{dust} \geq 10^{10.8} L_\sun) in the same photo-z range. It is found
that the mean ratios of the z=0.6 UV galaxies are
consistent with that of their z=0 counterparts of the same . For
IR galaxies, the mean ratios of the z=0.6 LIRGs (\rm
L_{dust} \sim 10^{11} L_\sun) are about a factor of 2 lower than local LIRGs,
whereas z=0.6 ULIRGs (\rm L_{dust} \sim 10^{12} L_\sun) have the same mean
ratios as their local counterparts. This is consistent
with the hypothesis that the dominant component of LIRG population has changed
from large, gas rich spirals at z to major-mergers at z=0. The stellar
mass of z=0.6 UV galaxies of \rm L_{FUV} \leq 10^{10.2} L_\sun is about a
factor 2 less than their local counterparts of the same luminosity, indicating
growth of these galaxies. The mass of z=0.6 UV lunmous galaxies (UVLGs: \rm
L_{FUV} > 10^{10.2} L_\sun) and IR selected galaxies, which are nearly
exclusively LIRGs and ULIRGs, is the same as their local counterparts.Comment: 27 pages, 8 figures, to be published in the Astrophysical Journal
Supplement series dedicated to GALEX result
Miniature exoplanet radial velocity array I: design, commissioning, and early photometric results
The MINiature Exoplanet Radial Velocity Array (MINERVA) is a US-based observational facility dedicated to the discovery and characterization of exoplanets around a nearby sample of bright stars. MINERVA employs a robotic array of four 0.7 m telescopes outfitted for both high-resolution spec- troscopy and photometry, and is designed for completely autonomous operation. The primary science program is a dedicated radial velocity survey and the secondary science objective is to obtain high precision transit light curves. The modular design of the facility and the flexibility of our hardware allows for both science programs to be pursued simultaneously, while the robotic control software provides a robust and efficient means to carry out nightly observations. In this article, we describe the design of MINERVA including major hardware components, software, and science goals. The telescopes and photometry cameras are characterized at our test facility on the Caltech campus in Pasadena, CA, and their on-sky performance is validated. New observations from our test facility demonstrate sub-mmag photometric precision of one of our radial velocity survey targets, and we present new transit observations and fits of WASP-52bâa known hot-Jupiter with an inflated radius and misaligned orbit. The process of relocating the MINERVA hardware to its final destination at the Fred Lawrence Whipple Observatory in southern Arizona has begun, and science operations are expected to commence within 2015
Dynamic clamp with StdpC software
Dynamic clamp is a powerful method that allows the introduction of artificial electrical components into target cells to simulate ionic conductances and synaptic inputs. This method is based on a fast cycle of measuring the membrane potential of a cell, calculating the current of a desired simulated component using an appropriate model and injecting this current into the cell. Here we present a dynamic clamp protocol using free, fully integrated, open-source software (StdpC, for spike timing-dependent plasticity clamp). Use of this protocol does not require specialist hardware, costly commercial software, experience in real-time operating systems or a strong programming background. The software enables the configuration and operation of a wide range of complex and fully automated dynamic clamp experiments through an intuitive and powerful interface with a minimal initial lead time of a few hours. After initial configuration, experimental results can be generated within minutes of establishing cell recording
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