971 research outputs found
Improving dialysis adherence for high risk patients using automated messaging: Proof of concept
AbstractComorbidities and socioeconomic barriers often limit patient adherence and self-management with hemodialysis. Missed sessions, often associated with communication barriers, can result in emergency dialysis and avoidable hospitalizations. This proof of concept study explored using a novel digital-messaging platform, EpxDialysis, to improve patient-to-dialysis center communication via widely available text messaging and telephone technology. A randomized controlled trial was conducted through Washington University-affiliated hemodialysis centers involving ESRD patients with poor attendance, defined as missing 2–6 sessions over the preceding 12 weeks. A cross-over study design evaluated appointment adherence between intervention and control groups. Comparing nonadherence rates eight weeks prior to enrollment, median appointment adherence after using the system increased by 75%, and median number of unintended hospitalization days fell by 31%. A conservative cost-benefit analysis of EpxDialysis demonstrates a 1:36 savings ratio from appointment adherence. EpxDialysis is a low-risk, cost-effective, intervention for increasing hemodialysis adherence in high-risk patients, especially at centers caring for vulnerable and low-income patients.</jats:p
Image processing techniques for improved porosity estimation
The work reported here is on the first phase of the development of an automated image analysis package. It is intended that the initial application should be to the problem of porosity estimation in powder metals. Although a great deal of work has been concentrated recently on using ultrasonic velocity changes and attenuation for porosity estimation, the problem can also be addressed through acoustical imaging
Element Abundances at High-redshift: Magellan MIKE Observations of sub-Damped Lyman-alpha Absorbers at 1.7 < z <2.4
We present chemical abundance measurements from high-resolution observations
of 5 sub-damped Lyman-alpha absorbers at 1.7 < z < 2.4 observed with the
Magellan Inamori Kyocera Echelle (MIKE) spectrograph on the 6.5-m Magellan II
Clay telescope. Lines of Zn II, Mg I, Mg II, Al II, Al III, S II, Si II, Si IV,
C II, C II*, C IV, Ni II, Mn II and Fe II were detected and column densities
were determined. The metallicity of the absorbing gas, inferred from the nearly
undepleted element Zn, is in the range of < -0.95 to +0.25 dex for the five
absorbers in our sample, with three of the systems being near-solar or
super-solar. We also investigate the effect of ionisation on the observed
abundances using photoionisation modelling. Combining our data with other
sub-DLA and DLA data from the literature, we report the most complete existing
determination of the metallicity vs. redshift relation for sub-DLAs and DLAs.
We confirm the suggestion from previous investigations that sub-DLAs are, on
average, more metal-rich than DLAs and evolve faster. We also discuss relative
abundances and abundance ratios in these absorbers. The more metal-rich systems
show significant dust depletion levels, as suggested by the ratios [Zn/Cr] and
[Zn/Fe]. For the majority of the systems in our sample, the [Mn/Fe] vs. [Zn/H]
trend is consistent with that seen previously for lower-redshift sub-DLAs. We
also measure the velocity width values for the sub-DLAs in our sample from
unsaturated absorption lines of Fe II 2344, 2374, 2600 A, and examine where
these systems lie in a plot of metallicity vs. velocity dispersion. Finally, we
examine cooling rate vs. H I column density in these sub-DLAs, and compare this
with the data from DLAs and the Milky Way ISM. We find that most of the systems
in our sample show higher cooling rate values compared to those seen in the
DLAs.Comment: Accepted for publication in the Monthly Notices of The Royal
Astronomical Societ
Solution of fractional Drinfeld-Sokolov-Wilson equation using Homotopy perturbation transform method
In this article, the approximate solutions of the non-linear Drinfeld-Sokolov-Wilson equation with fractional time derivative have been obtained. The fractional derivative is described in the Caputo sense. He’s polynomial is used to tackle the nonlinearity which arise in our considered problems. A time fractional nonlinear partial differential equation has been computed numerically. The numerical procedures illustrate the effectiveness and reliability of the method. Effects of fractional order time derivatives on the solutions for different particular cases are presented through graphs
Hubble Space Telescope Observations of Sub-Damped Lyman-alpha Absorbers at z < 0.5, and Implications for Galaxy Chemical Evolution
We report observations of four sub-damped Lyman-alpha (sub-DLA) quasar
absorbers at z<0.5 obtained with the Hubble Space Telescope Cosmic Origins
Spectrograph. We measure the available neutrals or ions of C, N, O, Si, P, S,
Ar, Mn, Fe, and/or Ni. Our data have doubled the sub-DLA metallicity samples at
z<0.5 and improved constraints on sub-DLA chemical evolution. All four of our
sub-DLAs are consistent with near-solar or super-solar metallicities and
relatively modest ionization corrections; observations of more lines and
detailed modeling will help to verify this. Combining our data with
measurements from the literature, we confirm previous suggestions that the
N(HI)-weighted mean metallicity of sub-DLAs exceeds that of DLAs at all
redshifts studied, even after making ionization corrections for sub-DLAs. The
absorber toward PHL 1598 shows significant dust depletion. The absorbers toward
PHL 1226 and PKS 0439-433 show the S/P ratio consistent with solar, i.e., they
lack a profound odd-even effect. The absorber toward Q0439-433 shows
super-solar Mn/Fe. For several sub-DLAs at z<0.5, [N/S] is below the level
expected for secondary N production, suggesting a delay in the release of the
secondary N or a tertiary N production mechanism. We constrain the electron
density using Si II* and C II* absorption. We also report different metallicity
vs. Delta V_90 relations for sub-DLAs and DLAs. For two sub-DLAs with
detections of emission lines from the underlying galaxies, our measurements of
the absorption-line metallicities are consistent with the emission-line
metallicities, suggesting that metallicity gradients are not significant in
these galaxies.Comment: 77 pages, 13 figures; accepted for publication in the Astrophysical
Journal. Submitted (in the original form) May 26, 2014; accepted Apr. 15,
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