11,021 research outputs found
New urea-absorbing polymers for artificial kidney machines
Etherified polymer is made from modified cellulose derivative which is reacted with periodate. It will absorb 2 grams of urea per 100 grams of polymer. Indications are that polymers could be used to help remove uremic wastes in artificial kidneys, or they could be administered orally as therapy for uremia
Aldehyde-containing urea-absorbing polysaccharides
A novel aldehyde containing polymer (ACP) is prepared by reaction of a polysaccharide with periodate to introduce aldehyde groups onto the C2 - C3 carbon atoms. By introduction of ether and ester groups onto the pendant primary hydroxyl solubility characteristics are modified. The ACP is utilized to absorb nitrogen bases such as urea in vitro or in vivo
Detection of solvents using a distributed fibre optic sensor
A fibre optic sensor that is capable of distributed detection of liquid solvents is presented. Sensor interrogation using optical time domain reflectometry (OTDR) provides the capability of locating solvent spills to a precision of ±2 m over a total sensor length that may extend to 20 km
ULTRACAM photometry of the eclipsing cataclysmic variable OU Vir
We present high-speed, three-colour photometry of the faint eclipsing
cataclysmic variable OU Vir. For the first time in OU Vir, separate eclipses of
the white dwarf and bright spot have been observed. We use timings of these
eclipses to derive a purely photometric model of the system, obtaining a mass
ratio of q = 0.175 +/- 0.025, an inclination of i = 79.2 +/- 0.7 degrees and a
disc radius of Rd/a = 0.2315 +/- 0.0150. We separate the white dwarf eclipse
from the lightcurve and, by fitting a blackbody spectrum to its flux in each
passband, obtain a white dwarf temperature of T = 21700 +/- 1200 K and a
distance of D = 650 +/- 210 pc. Assuming that the primary obeys the Nauenberg
(1972) mass-radius relation for white dwarfs and allowing for temperature
effects, we also find a primary mass Mw/Msun = 0.90 +/- 0.19, primary radius
Rw/Rsun = 0.0097 +/- 0.0031 and orbital separation a/Rsun = 0.75 +/- 0.05.Comment: 8 pages LaTeX, 6 figures. Accepted by MNRAS; erratum added at end.
Mon.Not.Roy.Astron.Soc. 347 (2004) 1173, erratum in pres
Dissipative Particle Dynamics with energy conservation
Dissipative particle dynamics (DPD) does not conserve energy and this
precludes its use in the study of thermal processes in complex fluids. We
present here a generalization of DPD that incorporates an internal energy and a
temperature variable for each particle. The dissipation induced by the
dissipative forces between particles is invested in raising the internal energy
of the particles. Thermal conduction occurs by means of (inverse) temperature
differences. The model can be viewed as a simplified solver of the fluctuating
hydrodynamic equations and opens up the possibility of studying thermal
processes in complex fluids with a mesoscopic simulation technique.Comment: 5 page
Academic self-concept, gender and single-sex schooling
This paper assesses gender differences in academic self-concept for a cohort of children born in 1958 (the National Child Development Study). We address the question of whether attending single-sex or co-educational schools affected studentsâ perceptions of their own academic abilities (academic self-concept). Academic selfconcept was found to be highly gendered, even controlling for prior test scores. Boys had higher self-concepts in maths and science, and girls in English. Single-sex schooling reduced the gender gap in self-concept, while selective schooling was linked to lower academic self-concept overall
Liver Transplantation in Older Patients
To the Editor: The impact of liver transplantation on public health policy has not been delineated, partly because of uncertainty about the upper age limit for candidacy. We have compared the outlook in 363 adult recipients of livers who were less than 50 years old (mean +SD, 35.8+8.5) and 92 recipients who were 50 to 77 years old (mean +SD, 55.7+4.8). Cyclosporine and steroids1,2 were used for immunosuppression, and monoclonal antilymphocyte globulin3 and azathioprine were added as needed. The techniques of liver transplantation4 were not influenced by the age of the patient. The indications for transplantation are shown in Figure 1âŠ., No extract is available for articles shorter than 400 words. © 1987, Massachusetts Medical Society. All rights reserved
Initial evidence for the criterion-related and structural validity of the long versions of the direct and meta-perspectives of the Coach-Athlete Relationship Questionnaire
This is the author's accepted manuscript. The final published article is available from the link below. Copyright @ 2010 Taylor & Francis.The aim of the present study was to develop and initially validate a longer version of the direct (Jowett & Ntoumanis, 2004) and meta-perspectives (Jowett, 2009a, 2009b) of the Coach-Athlete Relationship Questionnaire (CART-Q). In Study 1, instruments (e.g. questionnaires, scales, and inventories) that have been used to assess relationship quality in the broader psychological literature were examined and items potentially relevant to the coach-athlete relationship were identified. The content validity of the identified items was then assessed using expert panels. A final questionnaire was subsequently prepared and administered to 693 participants (310 coaches and 383 athletes). Confirmatory factor analysis was employed to assess the multidimensional nature of the questionnaire based on the 3Cs (i.e. closeness, commitment, and complementarity) model of the coach-athlete relationship. The findings indicated that the direct and meta-perspective items of the long versions of the CART-Q approached an adequate data fit. Moreover, evidence for the internal consistency and criterion validity of the new instruments was also obtained. In Study 2, the newly developed measure was administered to an independent sample of 251 individuals (145 athletes and 106 coaches). Further statistical support was gained for the factorial validity and reliability of the longer version of the CART-Q
A note on q-Gaussians and non-Gaussians in statistical mechanics
The sum of sufficiently strongly correlated random variables will not in
general be Gaussian distributed in the limit N\to\infty. We revisit examples of
sums x that have recently been put forward as instances of variables obeying a
q-Gaussian law, that is, one of type (cst)\times[1-(1-q)x^2]^{1/(1-q)}. We show
by explicit calculation that the probability distributions in the examples are
actually analytically different from q-Gaussians, in spite of numerically
resembling them very closely. Although q-Gaussians exhibit many interesting
properties, the examples investigated do not support the idea that they play a
special role as limit distributions of correlated sums.Comment: 17 pages including 3 figures. Introduction and references expande
Final Calibration of the Berkeley Extreme and Far-Ultraviolet Spectrometer on the ORFEUS-SPAS I and II Missions
The Berkeley Extreme and Far-Ultraviolet Spectrometer (BEFS) flew as part of
the ORFEUS telescope on the ORFEUS-SPAS I and II space-shuttle missions in 1993
and 1996, respectively. The data obtained by this instrument have now entered
the public domain. To facilitate their use by the astronomical community, we
have re-extracted and re-calibrated both data sets, converted them into a
standard (FITS) format, and placed them in the Multimission Archive at Space
Telescope (MAST). Our final calibration yields improved wavelength scales and
effective-area curves for both data sets.Comment: To appear in the January 2002 issue of the PASP. 17 pages with 9
embedded postscript figures; uses emulateapj5.st
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