570 research outputs found
Psychological analysis of social structure
It is an unfortunate result of the semi - practical aims which naturally influence social
philosophers, that they are apt throughout to
take up an indifferent, if not a hostile,
attitude to their given object. They hardly
believe in actual society as a botanist believes
in plants, or a biologist in vital processes.
And hence, social theory comes off badly. No
student can really appreciate an object for
which he is always apologising... It is in no
spirit of obscurantism ... that some t.ke up a
different position. They are convinced that
an actual living society is an infinitely higher
creature than a steam -engine, a plant, or an
animal; and that the best of their ideas are
not too good to be employed in analysing it
Photoelectric measurement of melanophoral activity of frog skin induced in vitro
No Abstract.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/50114/1/1030310202_ftp.pd
DuraSeal Exact is a safe adjunctive treatment for durotomy in spine: Postapproval study
Study designA nonrandomized, two-armed prospective study.ObjectiveWater-tight dural closure is paramount to the prevention of cerebrospinal fluid (CSF) leakage and associated complications. Synthetic polyethylene glycol (PEG) hydrogel has been used as an adjunct to sutured dural repair; however, its expansion postoperatively is a concern for neurological complications. A low-swell formulation of PEG sealant was introduced as DuraSeal Exact Spine Sealant System (DESS). A Post-Approval Study was performed primarily to evaluate the safety and efficacy of DESS for spinal dural repair compared to current alternatives, in a large patient population, reflecting a real-world practice.MethodsA total of 36 sites in the United States enrolled 429 patients treated with DESS as an adjunct to dural repair in the spinal sealant group and 406 patients treated with all other modalities in the control arm, from October 2011 to June 2016. The primary endpoint was the incidence of CSF leak within 90 days of operation. The secondary endpoints evaluated were deep surgical site infection and neurological serious adverse events.ResultsThe CSF leakage in the DESS group (6.6%) was not significantly different from the control group (6.5%) (p = .83), and there was no significant difference in the time to first leak. The two groups had no significant differences in deep surgical site infection (1.6% versus control 2.1%, p = .61) or proportion of subjects with neurological serious adverse events (2.9% versus control 1.6%, p = .516).ConclusionsDuraSeal Exact Spinal Sealant is safe when compared to current alternatives for spinal dural repair
The Substellar Mass Function: A Bayesian Approach
We report our efforts to constrain the form of the low-mass star and brown
dwarf mass function via Bayesian inference. Recent surveys of M, L, and T
dwarfs in the local solar neighborhood are an essential component of our study.
Uncertainties in the age distribution of local field stars make reliable
inference complicated. We adopt a wide range of plausible assumptions about the
rate of galactic star formation and show that their deviations from a uniform
rate produce little effect on the resulting luminosity function for a given
mass function. We use a Bayesian statistical formalism to evaluate the
probability of commonly used mass functions in light of recent discoveries. We
consider three functional forms of the mass function, include a two-segment
power law, a single power law with a low-mass cutoff, and a log-normal
distribution. Our results show that, at a 60% confidence level, the power-law
index, , for the low-mass arm of a two-segment power law has a value
between -0.5 and 0.5 for objects with masses between and . The best-fit index is at the 60% confidence
level for a single-segment mass function. Current data require this function
extend to at least with no restrictions placed on a lower mass
cutoff. Inferences of the parameter values for a log-normal mass function are
virtually unaffected by recent estimates of the local space density of L and T
dwarfs. We find no preference among these three forms using this method. We
discuss current and future capabilities that may eventually discriminate
between mass-function models and refine estimates of their associated parameter
values.Comment: 40 pages, 15 figures, 3 tables, accepted for publication in The
Astrophysical Journa
Constructing a WISE High Resolution Galaxy Atlas
After eight months of continuous observations, the Wide-field Infrared Survey
Explorer (WISE) mapped the entire sky at 3.4 {\mu}m, 4.6 {\mu}m, 12 {\mu}m and
22 {\mu}m. We have begun a dedicated WISE High Resolution Galaxy Atlas (WHRGA)
project to fully characterize large, nearby galaxies and produce a legacy image
atlas and source catalogue. Here we summarize the deconvolution technique used
to significantly improve the spatial resolution of WISE imaging, specifically
designed to study the internal anatomy of nearby galaxies. As a case study, we
present results for the galaxy NGC 1566, comparing the WISE super-resolution
image processing to that of Spitzer, GALEX and ground-based imaging. The is the
first paper in a two part series; results for a much larger sample of nearby
galaxies is presented in the second paper.Comment: Published in the AJ (2012, AJ, 144, 68
A new method of measuring the cluster peculiar velocity power spectrum
We propose to use spatial correlations of the kinetic Sunyaev-Zeldovich (KSZ)
flux as an estimator of the peculiar velocity power spectrum. In contrast with
conventional techniques, our new method does not require measurements of the
thermal SZ signal or the X-ray temperature. Moreover, this method has the
special advantage that the expected systematic errors are always sub-dominant
to statistical errors on all scales and redshifts of interest. We show that
future large sky coverage KSZ surveys may allow a peculiar velocity power
spectrum estimates of an accuracy reaching ~10%.Comment: 5 pages, 2 figures, MNRAS in Press (doi:
10.1111/j.1365-2966.2008.13454.x
Supernovae without host galaxy? - Hypervelocity stars in foreign galaxies
Harvesting the SAI supernova catalog, we search for SNe that apparently do
not occur within a distinct host galaxy but lie a great distance apart from
their assigned host galaxy. Assuming two possible explanations for this
host-lessness of a fraction of reported SNe, namely (i) a host galaxy which is
too faint to be detected within the limits of currently available surveys or
(ii) a hypervelocity star (HVS) as progenitor of the SN,we want to distinguish
between these two cases. To do so, we use deep imaging to test explanation (i).
If within our detection limit of 27 mag/arcsec^2, the central surface
brightness of the faintest known LSB galaxy so far, no galaxy could be
identified, we discard this explanation and regard the SN, after several other
checks, to have had a hypervelocity star progenitor. Analyzing a selected
subsample of five host-less SNe we find one, SN 2006bx in UGC5434, to be put in
the hypervelocity progenitor category with a high probability, exhibiting a
projected velocity of > 800 km/s. SN 1969L in NGC1058 is most likely an example
for a very extended star-forming disk visible only in the far-UV, not in the
optical wavebands. Therefore this SN is clearly due to in situ star formation.
This mechanism may also apply for two other SNe we investigated (SN 1970L and
SN 1997C), but this cannot be determined with final certainty. Another one, SN
2005nc associated with a gamma-ray burst (GRB 050525), is a special case not
covered by our initial assumptions. Even with deep Hubble data, a host galaxy
could not be unambiguously identified.Comment: 11 pages, 7 figures, accepted for publication by A&A, abstract
abridged due to arXiv requirements, rev. 2 after language correction
Survival and Growth of Hatchling Crocodylus porosus in Saltwater Without Access to Fresh Drinking Water
It has been suggested that C. porosus select nest sites which provide a source of freshwater for hatchlings during the dry season. From a mark-recapture study, we conclude that hatchling C. porosus can survive and grow in hyperosmotic saltwater without drinking fresh water. Hence, the siting of nests is unlikely to be the consequence of a requirement by hatchlings for fresh water. Considered along with other information, our observations imply that hatchling C. porosus have functional salt glands
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