18,561 research outputs found
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Assessment of the tissue distribution of transplanted human endothelial progenitor cells by radioactive labeling
Background— Transplantation of endothelial progenitor cells (EPCs) improves vascularization and left ventricular function after experimental myocardial ischemia. However, tissue distribution of transplanted EPCs has not yet been monitored in living animals. Therefore, we tested whether radioactive labeling allows us to detect injected EPCs
Consequences of wall stiffness for a beta-soft potential
Modifications of the infinite square well E(5) and X(5) descriptions of
transitional nuclear structure are considered. The eigenproblem for a potential
with linear sloped walls is solved. The consequences of the introduction of
sloped walls and of a quadratic transition operator are investigated.Comment: RevTeX 4, 8 pages, as published in Phys. Rev.
Sonoluminescing air bubbles rectify argon
The dynamics of single bubble sonoluminescence (SBSL) strongly depends on the
percentage of inert gas within the bubble. We propose a theory for this
dependence, based on a combination of principles from sonochemistry and
hydrodynamic stability. The nitrogen and oxygen dissociation and subsequent
reaction to water soluble gases implies that strongly forced air bubbles
eventually consist of pure argon. Thus it is the partial argon (or any other
inert gas) pressure which is relevant for stability. The theory provides
quantitative explanations for many aspects of SBSL.Comment: 4 page
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Emergency department visits for acute asthma by adults who ran out of their inhaled medications
This study was designed to determine the percentage of asthma-related emergency department (ED) visits made by patients who recently ran out of their inhaled short-acting beta-agonists or inhaled corticosteroids and to characterize this understudied patient population. A secondary analysis was performed of data from four ED-based multicenter studies of acute asthma during 1996–1998 (n = 64 EDs). In each study, consecutive adult patients, aged 18–54 years, with acute asthma underwent a structured interview that assessed running out of inhaled medications. The analytic cohort comprised 1095 adults. Overall, 324 patients (30%; 95% confidence interval [CI], 27–32%) ran out of either of their inhaled beta-agonists or inhaled corticosteroids during the week before their index ED visit; 311 (28%; 95% CI, 26–31%) ran out of inhaled beta-agonists per se. Among a subset of 518 patients on inhaled corticosteroids, 55 patients (11%; 95% CI, 8–14%) ran out of inhaled corticosteroids. In the multivariable model, predictors of running out of an asthma medication were male sex, non-Hispanic black race, Hispanic ethnicity, no insurance, lower household income, and use of EDs as the preferred source of asthma prescriptions (all p < 0.05). Among patients who ran out of medications, 49% (95% CI, 43–55%) ran out of inhaled beta-agonists and 72% (95% CI, 58–84%) ran out of inhaled corticosteroids, before onset of their acute asthma symptoms. In 1095 adult ED patients with acute asthma, we found that 30% ran out of their inhaled asthma medications before the ED visit. Asthma patients who ran out of medications had sociodemographic characteristics that may help with identification of preventable ED visits. Multifaceted strategies needed to ensure optimal use of inhaled medications are warranted
Encapsulation of phosphorus dopants in silicon for the fabrication of a quantum computer
The incorporation of phosphorus in silicon is studied by analyzing phosphorus
delta-doped layers using a combination of scanning tunneling microscopy,
secondary ion mass spectrometry and Hall effect measurements. The samples are
prepared by phosphine saturation dosing of a Si(100) surface at room
temperature, a critical annealing step to incorporate phosphorus atoms, and
subsequent epitaxial silicon overgrowth. We observe minimal dopant segregation
(5 nm), complete electrical activation at a silicon growth temperature of 250
degrees C and a high two-dimensional electron mobility of 100 cm2/Vs at a
temperature of 4.2 K. These results, along with preliminary studies aimed at
further minimizing dopant diffusion, bode well for the fabrication of
atomically precise dopant arrays in silicon such as those found in recent
solid-state quantum computer architectures.Comment: 3 pages, 4 figure
Using participatory design and visual narrative inquiry to investigate researchers’ data challenges and recommendations for library research data services
Purpose – The purpose of this paper is to report on an information gathering study on users’ research data-related challenges and proposals for library research data services (RDS). This study probes how early career researchers visually conceptualize the research process in their disciplines, their self-reported research data challenges, and their recommendations for library RDS. Design/methodology/approach – Two focus group sessions were undertaken with a total of eight early career researchers. Adopting the visual narrative inquiry method, the participants were asked to sketch the general research process in their domain. The individuals’ illustrations of the research process were then used as the basis for reflecting on their data-related needs and potential RDS that would assist them during the research process. Findings – Participants presented a research process that was more personal and, in most cases, more imperfect than the research lifecycle models that academic libraries are increasingly using for RDS development and communication. The authors present their data-related challenges, which included data access barriers, low knowledge of best practices for research data management, the need for a deeper understanding of post-publication impact, and inconsistent awareness of existing library and institution RDS. The authors outline RDS recommendations that participants proposed, which included a web-based tools, customized training sessions, and “distilled” guides to research data best practices. Practical implications – The study flagged users’ gaps in understandings of existing library and institutional RDS, suggesting that there may be an opportunity to engage users in the design of communications plans for services. The findings from this user study will inform the development of RDS at the institution. Originality/value – This paper puts forth a methodological approach that academic libraries can adapt for understanding users’ needs and user-generated design solutions
General theory for integer-type algorithm for higher order differential equations
Based on functional analysis, we propose an algorithm for finite-norm
solutions of higher-order linear Fuchsian-type ordinary differential equations
(ODEs) P(x,d/dx)f(x)=0 with P(x,d/dx):=[\sum_m p_m (x) (d/dx)^m] by using only
the four arithmetical operations on integers. This algorithm is based on a
band-diagonal matrix representation of the differential operator P(x,d/dx),
though it is quite different from the usual Galerkin methods. This
representation is made for the respective CONSs of the input Hilbert space H
and the output Hilbert space H' of P(x,d/dx). This band-diagonal matrix enables
the construction of a recursive algorithm for solving the ODE. However, a
solution of the simultaneous linear equations represented by this matrix does
not necessarily correspond to the true solution of ODE. We show that when this
solution is an l^2 sequence, it corresponds to the true solution of ODE. We
invent a method based on an integer-type algorithm for extracting only l^2
components. Further, the concrete choice of Hilbert spaces H and H' is also
given for our algorithm when p_m is a polynomial or a rational function with
rational coefficients. We check how our algorithm works based on several
numerical demonstrations related to special functions, where the results show
that the accuracy of our method is extremely high.Comment: Errors concerning numbering of figures are fixe
Chemotactic Collapse and Mesenchymal Morphogenesis
We study the effect of chemotactic signaling among mesenchymal cells. We show
that the particular physiology of the mesenchymal cells allows one-dimensional
collapse in contrast to the case of bacteria, and that the mesenchymal
morphogenesis represents thus a more complex type of pattern formation than
those found in bacterial colonies. We finally compare our theoretical
predictions with recent in vitro experiments
Automatic correction of hand pointing in stereoscopic depth
In order to examine whether stereoscopic depth information could drive fast automatic correction of hand pointing, an experiment was designed in a 3D visual environment in which participants were asked to point to a target at different stereoscopic depths as quickly and accurately as possible within a limited time window (≤300 ms). The experiment consisted of two tasks: "depthGO" in which participants were asked to point to the new target position if the target jumped, and "depthSTOP" in which participants were instructed to abort their ongoing movements after the target jumped. The depth jump was designed to occur in 20% of the trials in both tasks. Results showed that fast automatic correction of hand movements could be driven by stereoscopic depth to occur in as early as 190 ms.This work was supported by the Grants from the National Natural Science Foundation of China (60970062 and 61173116) and the Doctoral Fund of Ministry of Education of China (20110072110014)
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