1,109 research outputs found
Design effects for multiple design samples
In some situations the sample design of a survey is rather complex, consisting of fundamentally different designs in different domains. The design effect for estimates based upon the total sample is a weighted sum of the domainspecific design effects. We derive these weights under an appropriate model and illustrate their use with data from the European Social Survey (ESS)
Approximations to b* in the prediction of design effects due to clustering
Kish’s well-known expression for the design effect due to clustering is often used to inform sample design, using an approximation such as b in place of b. If the design involves either weighting or variation in cluster sample sizes, this can be a poor approximation. In this article we discuss the sensitivity of the approximation to departures from the implicit assumptions and propose an alternative approximation
Model collaboration: university library system and rehabilitation research team to advance telepractice knowledge.
This Publisher's Report describes the collaboration between a university library system's scholarly communication and publishing office and a federally funded research team, the Rehabilitation Engineering Research Center (RERC) on Telerehabilitation. This novel interdisciplinary collaboration engages librarians, information technologists, publishing professionals, clinicians, policy experts, and engineers and has produced a new Open Access journal, International Journal of Telerehabilitation, and a developing, interactive web-based product dedicated to disseminating information about telerehabilitation. Readership statistics are presented for March 1, 2011 - February 29, 2012
Scholarly Communication and Publishing Lunch and Learn Talks
This series of talks focuses on issues in scholarly communication and publishing presented to University Library System (ULS), University of Pittsburgh colleagues by staff members of the ULS Office of Scholarly Communication and Publishing. Many of these talks feature "toolbox" tips on how to apply knowledge gained from the talks. Links to recordings of the talks are provided when available. For topics and presentations, see the record for each talk
Three-dimensional Models of Core-collapse Supernovae From Low-mass Progenitors With Implications for Crab
We present 3D full-sphere supernova simulations of non-rotating low-mass (~9
Msun) progenitors, covering the entire evolution from core collapse through
bounce and shock revival, through shock breakout from the stellar surface,
until fallback is completed several days later. We obtain low-energy explosions
[~(0.5-1.0)x 10^{50} erg] of iron-core progenitors at the low-mass end of the
core-collapse supernova (LMCCSN) domain and compare to a super-AGB (sAGB)
progenitor with an oxygen-neon-magnesium core that collapses and explodes as
electron-capture supernova (ECSN). The onset of the explosion in the LMCCSN
models is modelled self-consistently using the Vertex-Prometheus code, whereas
the ECSN explosion is modelled using parametric neutrino transport in the
Prometheus-HOTB code, choosing different explosion energies in the range of
previous self-consistent models. The sAGB and LMCCSN progenitors that share
structural similarities have almost spherical explosions with little metal
mixing into the hydrogen envelope. A LMCCSN with less 2nd dredge-up results in
a highly asymmetric explosion. It shows efficient mixing and dramatic shock
deceleration in the extended hydrogen envelope. Both properties allow fast
nickel plumes to catch up with the shock, leading to extreme shock deformation
and aspherical shock breakout. Fallback masses of <~5x10^{-3} Msun have no
significant effects on the neutron star (NS) masses and kicks. The anisotropic
fallback carries considerable angular momentum, however, and determines the
spin of the newly-born NS. The LMCCSNe model with less 2nd dredge-up results in
a hydrodynamic and neutrino-induced NS kick of >40 km/s and a NS spin period of
~30 ms, both not largely different from those of the Crab pulsar at birth.Comment: 47 pages, 27 figures, 6 tables; minor revisions, accepted by MNRA
Scholarly Communication and Publishing Lunch and Learn Talk #1: ULS Journal Publishing -- Why We Do It
This series of talks focuses on issues in scholarly communication and publishing presented to University Library System (ULS), University of Pittsburgh colleagues by staff members of the ULS Office of Scholarly Communication and Publishing. Many of these talks feature "toolbox" tips on how to apply knowledge gained from the talks. Links to recordings of the talks are provided when available. For topics and presentations, see the record for each talk
Short-term exposure to heat stress attenuates appetite and intestinal integrity in growing pigs 1
Acute heat stress (HS) and heat stroke can be detrimental to the health, well-being, and performance of mammals such as swine. Therefore, our objective was to chronologically characterize how a growing pig perceives and initially copes with a severe heat load. Crossbred gilts (n=32; 63.8±2.9 kg) were subjected to HS conditions (37°C and 40% humidity) with ad libitum intake for 0, 2, 4, or 6 h (n=8/time point). Rectal temperature (Tr), respiration rates (RR), and feed intake were determined every 2 h. Pigs were euthanized at each time point and fresh ileum and colon samples were mounted into modified Ussing chambers to assess ex vivo intestinal integrity and function. Transepithelial electrical resistance (TER) and fluorescein isothiocyanate-labeled dextran (FD4) permeability were assessed. As expected, Tr increased linearly over time (P\u3c0.001) with the highest temperature observed at 6 h of HS. Compared to the 0-h thermal-neutral (TN) pigs, RR increased (230%; P\u3c0.001) in the first 2 h and remained elevated over the 6 h of HS (P\u3c0.05). Feed intake was dramatically reduced due to HS and this corresponded with significant changes in plasma glucose, ghrelin, and glucose-dependent insulinotropic peptide (P\u3c0.050). At as early as 2 h of HS, ileum TER linearly decreased (P\u3c0.01), while FD4 linearly increased with time (P\u3c0.05). Colon TER and FD4 changed due to HS in quadratic responses over time (P=0.050) similar to the ileum but were less pronounced. In response to HS, ileum and colon heat shock protein (HSP) 70 mRNA and protein abundance increased linearly over time (P\u3c0.050). Altogether, these data indicated that a short duration of HS (2-6 h) compromised feed intake and intestinal integrity in growing pigs
Scholarly Communication and Publishing Lunch and Learn Talk #12: Kickstarting Open Access Week 2014
For the June 2014 talk, we discussed plans for Open Access Week 2014, the 7th Open Access Week commemorated internationally and the 4th at Pitt. We began with a report on the recent SPARC-sponsored 2014 Open Access Week Planning Kickoff Webcast. Featuring speakers from California, Kansas, and Kenya, the webcast offered many good ideas on how to engage faculty, students, and library colleagues in Open Access Week activities and scholarly communications issues. Then we continued with some brainstorming to generate ideas on how we can use Open Access Week to get our message out about the open sharing of knowledge and how we can all deliver that message in a way that resonates with Pitt faculty and students. We also discussed some of our ideas for this year's Open Access Week, scheduled for October 20-26, 2014
Strangeness Enhancement in Heavy Ion Collisions - Evidence for Quark-Gluon-Matter ?
The centrality dependence of (multi-)strange hadron abundances is studied for
Pb(158 AGeV)Pb reactions and compared to p(158 GeV)Pb collisions. The
microscopic transport model UrQMD is used for this analysis. The predicted
Lambda/pi-, Xi-/pi- and Omega-/pi- ratios are enhanced due to rescattering in
central Pb-Pb collisions as compared to peripheral Pb-Pb or p-Pb collisions. A
reduction of the constituent quark masses to the current quark masses m_s \sim
230 MeV, m_q \sim 10 MeV, as motivated by chiral symmetry restoration, enhances
the hyperon yields to the experimentally observed high values. Similar results
are obtained by an ad hoc overall increase of the color electric field strength
(effective string tension of kappa=3 GeV/fm). The enhancement depends strongly
on the kinematical cuts. The maximum enhancement is predicted around
midrapidity. For Lambda's, strangeness suppression is predicted at
projectile/target rapidity. For Omega's, the predicted enhancement can be as
large as one order of magnitude. Comparisons of Pb-Pb data to proton induced
asymmetric (p-A) collisions are hampered due to the predicted strong asymmetry
in the various rapidity distributions of the different (strange) particle
species. In p-Pb collisions, strangeness is locally (in rapidity) not
conserved. The present comparison to the data of the WA97 and NA49
collaborations clearly supports the suggestion that conventional (free)
hadronic scenarios are unable to describe the observed high (anti-)hyperon
yields in central collisions. The doubling of the strangeness to nonstrange
suppression factor, gamma_s \approx 0.65, might be interpreted as a signal of a
phase of nearly massless particles.Comment: published version, discussion on strange mesons and new table added,
extended discussion on strange baryon yields. Latex, 20 pages, including 5
eps-figure
Puerperal influence of bovine uterine health status on the mRNA expression of pro-inflammatory factors
After parturition, uterine bacterial infections lead to inflammatory processes
such as subclinical/clinical endometritis with high prevalence in dairy cows.
Endometrial epithelial cells participate in this immune response with the
production of pro-inflammatory factors. The objective of the present study was
to evaluate the endometrial mRNA expression pattern of pro inflammatory
factors during a selected postpartum (pp) period. Dairy cows with three
different uterine health conditions on days 24-30 pp (healthy: n = 11,
subclinical endometritis: n = 10, clinical endometritis: n = 10) were sampled
using the cytobrush technique. Subsequently, each cow was sampled 3 more times
in weekly intervals (days 31-37 pp; days 38-44 pp; days 45-51 pp). Samples
were subjected to mRNA analysis performed by RT-qPCR. Additionally, an
analysis of cultivable bacteria was performed at the early/late stage of the
selected puerperal period. mRNA expression of 16 candidate genes was analyzed
by using two different approaches. The first approach referred to the initial
grouping on days 24-30 pp to reveal long-term effects of the uterine health on
the subsequent puerperal period. The second approach considered the current
uterine health status at each sampling to elucidate the impact of different
points in time. Long-term effects seem to appear for chemokines, prostacyclin
synthase and prostaglandin D2 synthase. If related to the current uterine
health, the majority of candidate genes were significantly higher expressed in
endometritic cows on days 45-51 pp in contrast to earlier stages of the
puerperium. Microbiological analysis revealed the significantly higher
prevalence of Trueperella pyogenes findings in cows with clinical endometritis
on days 24-30 pp, but no correlations were found on days 45-51 pp. In
conclusion, a strong immune response to subclinical/clinical endometritis in
the late puerperium may be related to the negative impact of these conditions
on reproductive performance in dairy cows
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