1,733 research outputs found
Seven fat years or seven lean years for freight transport modelling? Developments since 2013.
Freight transport modelling has seen many developments in this century. A key trend was the inclusion of more aspects of logistics thinking in freight transport models for the public sector. In de Jong et al. (2013) is a list of topics that were expected to be the main areas for further development in freight transport modelling in the next decade. The current paper describes the developments that have actually taken place in modelling freight transport, at the international, national, regional, and urban level, and compares these to the list in the 2013 paper
Providing person-centered care for patients with complex healthcare needs: A qualitative study
Background People with chronic conditions have complex healthcare needs that lead to challenges for adequate healthcare provision. Current healthcare services do not always respond adequately to their needs. A modular perspective, in particular providing visualization of the modular service architecture, is promising for improving the responsiveness of healthcare services to the complex healthcare needs of people with chronic conditions. The modular service architecture provides a comprehensive representation of the components and modules of healthcare provision. In this study, we explore this further in a qualitative multiple case study on healthcare provision for children with Down syndrome in the Netherlands. Methods Data collection for four cases involved 53 semi-structured interviews with healthcare professionals and 21 semi-structured interviews with patients (the parents of children with Down syndrome as proxy). In addition, we gathered data by means of practice observations and analysis of relevant documents. The interviews were audio-recorded, transcribed verbatim and analyzed utilizing the Miles and Huberman approach. Results Our study shows that the perspectives on healthcare provision of professionals and patients differ substantially. The visualization of the modular service architecture that was based on the healthcare professionalsâ perspective provided a complete representation of (para)medical outcomes relevant to the professionalsâ own discipline. In contrast, the modular service architecture based on the patientsâ perspective, which we define as a person-centered modular service architecture, provided a representation of the healthcare service that was primarily based on functional outcomes and the overall wellbeing of the patients. Conclusion Our study shows that visualization of the modular service architecture can be a useful tool to better address the complex needs and requirements of people with a chronic condition. We suggest that a person-centered modular service architecture that focuses on functional outcomes and overall wellbeing, enables increased responsiveness of healthcare services to people with complex healthcare needs and provision of truly person-centered care
Detection of Coxiella burnetii in complex matrices by using multiplex quantitative PCR during a major Q fever outbreak in the Netherlands
Q fever, caused by Coxiella burnetii, is a zoonosis with a worldwide distribution. A large rural area in the southeast of the Netherlands was heavily affected by Q fever between 2007 and 2009. This initiated the development of a robust and internally controlled multiplex quantitative PCR (qPCR) assay for the detection of C. burnetii DNA in veterinary and environmental matrices on suspected Q fever-affected farms. The qPCR detects three C. burnetii targets (icd, com1, and IS1111) and one Bacillus thuringiensis internal control target (cry1b). Bacillus thuringiensis spores were added to samples to control both DNA extraction and PCR amplification. The performance of the qPCR assay was investigated and showed a high efficiency; a limit of detection of 13.0, 10.6, and 10.4 copies per reaction for the targets icd, com1, and IS1111, respectively; and no crossreactivity with the nontarget organisms tested. Screening for C. burnetii DNA on 29 suspected Q fever-affected farms during the Q fever epidemic in 2008 showed that swabs from dust-accumulating surfaces contained higher levels of C. burnetii DNA than vaginal swabs from goats or sheep. PCR inhibition by coextracted substances was observed in some environmental samples, and 10- or 100-fold dilutions of samples were sufficient to obtain interpretable signals for both the C. burnetii targets and the internal control. The inclusion of an internal control target and three C. burnetii targets in one multiplex qPCR assay showed that complex veterinary and environmental matrices can be screened reliably for the presence of C. burnetii DNA during an outbreak. © 2011, American Society for Microbiology
Spin-triplet superconductivity in quasi-one dimension
We consider a system with electron-phonon interaction, antiferromagnetic
fluctuations and disconnected open Fermi surfaces. The existence of odd-parity
superconductivity in this circumstance is shown for the first time. If it is
applied to the quasi-one-dimensional systems like the organic conductors
(TMTSF)_2X we obtain spin-triplet superconductivity with nodeless gap. Our
result is also valid in higher dimensions(2d and 3d).Comment: 2 page
Relatie tussen bestrijdingsmiddelen en biota in oppervlaktewater : een haalbaarheidsstudie naar toepassingsmogelijkheden van multivariate analysetechnieken
Environmental Biology - ol
Between overt and covert research: concealment and disclosure in an ethnographic study of commercial hospitality
This article examines the ways in which problems of concealment emerged in an ethnographic study of a suburban bar and considers how disclosure of the research aims, the recruitment of informants, and elicitation of information was negotiated throughout the fieldwork. The case study demonstrates how the social context and the relationships with specific informants determined overtness or covertness in the research. It is argued that the existing literature on covert research and covert methods provides an inappropriate frame of reference with which to understand concealment in fieldwork. The article illustrates why concealment is sometimes necessary, and often unavoidable, and concludes that the criticisms leveled against covert methods should not stop the fieldworker from engaging in research that involves covertness
The initial conditions of isolated star formation - VI. SCUBA mapping of prestellar cores
Observations have been carried out with SCUBA at the JCMT of 52 molecular
cloud cores that do not contain any sign of protostellar activity. These are
all therefore candidate prestellar cores, which are believed to represent the
stage of star formation that precedes the formation of a protostar. 29 of the
52 cores were detected at 850 microns at varying levels of signal-to-noise
ratio greater than 3 sigma at peak. The detected cores were split into 'bright'
cores and `intermediate' cores, depending on their peak flux density at 850
microns. Cores with peak 850 microns flux densities greater than 170 mJy/beam
were designated 'bright' (13 cores), while those flux densities below this
value were designated 'intermediate' (16 cores). This dividing line corresponds
to A_v~50 under typical assumptions. The data are combined with our previously
published ISO data, and the physical parameters of the cores, such as density
and temperature, are calculated. Detailed fitting of the bright core radial
profiles shows that they are not critical Bonnor-Ebert spheres, in agreement
with previous findings. However, we find that intermediate cores, such as B68
(which has previously been claimed to be a Bonnor-Ebert sphere), may in fact be
consistent with the Bonnor-Ebert criterion, suggesting perhaps that cores pass
through such a phase during their evolution. We make rough estimates of core
lifetimes based on the statistics of detections and find that the lifetime of a
prestellar core is roughly ~3x10^5 years, while that of a bright core is
\~1.5x10^5 years. Comparisons with some magnetic and turbulence regulated
collapse models show that no model can match all of the data. Models that are
tuned to fit the total prestellar core lifetime, do not predict the relative
numbers of cores seen at each stage.Comment: 23 pages, 52 figures, accepted by MNRAS, alternate PDF w/all figures
available from
http://www.astro.cf.ac.uk/pub/Derek.Ward-Thompson/publications.htm
Structure in the 3D Galaxy Distribution: I. Methods and Example Results
Three methods for detecting and characterizing structure in point data, such
as that generated by redshift surveys, are described: classification using
self-organizing maps, segmentation using Bayesian blocks, and density
estimation using adaptive kernels. The first two methods are new, and allow
detection and characterization of structures of arbitrary shape and at a wide
range of spatial scales. These methods should elucidate not only clusters, but
also the more distributed, wide-ranging filaments and sheets, and further allow
the possibility of detecting and characterizing an even broader class of
shapes. The methods are demonstrated and compared in application to three data
sets: a carefully selected volume-limited sample from the Sloan Digital Sky
Survey redshift data, a similarly selected sample from the Millennium
Simulation, and a set of points independently drawn from a uniform probability
distribution -- a so-called Poisson distribution. We demonstrate a few of the
many ways in which these methods elucidate large scale structure in the
distribution of galaxies in the nearby Universe.Comment: Re-posted after referee corrections along with partially re-written
introduction. 80 pages, 31 figures, ApJ in Press. For full sized figures
please download from: http://astrophysics.arc.nasa.gov/~mway/lss1.pd
Shell formation and star formation in superbubble DEM 192
Was star formation in the OB associations, LH 51 and LH 54, triggered by the
growth of the superbubble DEM 192? To examine this possibility, we investigate
the stellar contents and star formation history, and model the evolution of the
shell. H-R diagrams constructed from UBV photometry and spectral
classifications indicate highly coeval star formation, with the entire massive
star population having an age of ~< 2-3 Myr. However, LH 54 is constrained to
an age of ~3 Myr by the presence of a WR star, and the IMF for LH 51 suggests a
lower-mass limit implying an age of 1-2 Myr. There is no evidence of an earlier
stellar population to create the superbubble, but the modeled shell kinematics
are consistent with an origin due to the strongest stellar winds of LH 54. It
might therefore be possible that LH 54 created the superbubble, which in turn
may have triggered the creation of LH 51. Within the errors, the spatial
distribution of stellar masses and IMF appear uniform within the associations.
We reinvestigate the estimates for stellar wind power L_w(t), during the
H-burning phase, and note that revised mass-loss rates yield a significantly
different form for L_w(t), and may affect stellar evolution timescales. We also
model superbubble expansion into an ambient medium with a sudden, discontinuous
drop in density, and find that this can easily reproduce the anomalously high
shell expansion velocities seen in many superbubbles.Comment: 18 pages, 12 figures, AASTeX; Figure 1 bitmapped. Accepted to AJ.
Table of Contents and preprint, including hi-resolution version of Figure 1,
available at: http://www.ast.cam.ac.uk/~oey/oeypubs.htm
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