822 research outputs found
Samenspel duurzaam en gezond?; Duurzaam eten in consumentenperspectief
Om de consument te informeren over gezondere en duurzamere voedselpatronen wil het ministerie van EL&I wil weten in hoeverre consumenten samenhang ervaren tussen duurzaamheid en gezondheid. In het onderzoek is de beschikbare literatuur over consumentenpercepties van gezonde en duurzame voedselkeuzes bestudeerd. Vervolgens is tijdens drie focusgroepen, ieder met zes deelnemers, onderzocht hoe consumenten omgaan met de combinatie van gezondheid en duurzaamheid in hun voedselkeuzes. Tot slot is na een online survey onder een steekproef van 942 consumenten getoetst in hoeverre zij voor verschillende producten een verband zien tussen gezondheid en verschillende aspecten van duurzaamheid
Insulating and Conducting Phases of RbC60
Optical measurements were performed on thin films of RbC,
identified by X-ray diffraction as mostly material. The samples were
subjected to various heat treatments, including quenching and slow cooling from
400K. The dramatic increase in the transmission of the quenched samples, and
the relaxation towards the transmission observed in slow cooled samples
provides direct evidence for the existence of a metastable insulating phase.
Slow cooling results in a phase transition between two electrically conducting
phases.Comment: Minor revisions. Submitted to PRB, RevTeX 3.0 file, 2 postscript
figures included, ir_dop
Structure and properties of a novel fulleride Sm6C60
A novel fulleride Sm6C60 has been synthesized using high temperature solid
state reaction. The Rietveld refinement on high resolution synchrotron X-ray
powder diffraction data shows that Sm6C60 is isostructural with body-centered
cubic A6C60 (A=K, Ba). Raman spectrum of Sm6C60 is similar to that of Ba6C60,
and the frequencies of two Ag modes in Sm6C60 are nearly the same as that of
Ba6C60, suggesting that Sm is divalent and hybridization between C60 molecules
and the Sm atom could exist in Sm6C60. Resistivity measurement shows a weak
T-linear behavior above 180 K, the transport at low temperature is mainly
dominated by granular-metal theory.Comment: 9 pages, 3 figures, submitted to Phys. Rev. B (March 12, 1999
Neonatal sepsis in alloimmune hemolytic disease of the fetus and newborn: a retrospective cohort study of 260 neonates
Background: Among neonates with hemolytic disease of the fetus and newborn (HDFN), we aimed to describe the frequency of central-line use, indications for insertion, and incidence of confirmed and suspected sepsis, including antibiotic treatment over a 10-year surveillance period. Study Design and Methods: All neonates with HDFN admitted to our neonatal intensive care unit between January 2012 and December 2021 were included in this retrospective, cohort study. Annual proportions of infants with a central-line and central-line-associated bloodstream infection (CLABSI) rates (per 1000 central-line days and per 100 infants) were evaluated. Numbers of confirmed and suspected early- and late-onset sepsis episodes were assessed over the entire study period. Results: Of the 260 included infants, 25 (9.6%) were evaluated for suspected sepsis, with 16 (6.2%) having >= 1 confirmed sepsis episode. A total of 123 central-lines were placed in 98 (37.7%) neonates, with impending exchange transfusion (ET) being the most frequent indication. Of the 34 (34.7%) neonates in whom a central-line was placed due to impending ET, 11 (32.4%) received no ET. Overall CLABSI incidence was 13.58 per 1000 central-line days. Neonates with a central-line had a higher risk for confirmed late-onset infection (RR 1.11, 95% CI: 1.04-1.20) and sepsis work-up (RR 1.10, 95% CI: 1.03-1.17) compared to infants without a central-line. Conclusions: Sepsis incidence among neonates with HDFN remains high, in particular in those with a central-line. Considering the substantial proportion of neonates with a central-line without eventual ET, central-line placement should be delayed until the likelihood of ET is high.Developmen
Tests of CPT Invariance at Neutrino Factories
We investigate possible tests of CPT invariance on the level of event rates
at neutrino factories. We do not assume any specific model but phenomenological
differences in the neutrino-antineutrino masses and mixing angles in a Lorentz
invariance preserving context, such as it could be induced by physics beyond
the Standard Model. We especially focus on the muon neutrino and antineutrino
disappearance channels in order to obtain constraints on the
neutrino-antineutrino mass and mixing angle differences; we found, for example,
that the sensitivity
could be achieved.Comment: 6 pages, 1 figure, RevTeX4. Final version to be published in Phys.
Rev.
Ab Initio Calculation of the Lattice Distortions induced by Substitutional Ag- and Cu- Impurities in Alkali Halide Crystals
An ab initio study of the doping of alkali halide crystals (AX: A = Li, Na,
K, Rb; X = F, Cl, Br, I) by ns2 anions (Ag- and Cu-) is presented. Large active
clusters with 179 ions embedded in the surrounding crystalline lattice are
considered in order to describe properly the lattice relaxation induced by the
introduction of substitutional impurities. In all the cases considered, the
lattice distortions imply the concerted movement of several shells of
neighbors. The shell displacements are smaller for the smaller anion Cu-, as
expected. The study of the family of rock-salt alkali halides (excepting CsF)
allows us to extract trends that might be useful at a predictive level in the
study of other impurity systems. Those trends are presented and discussed in
terms of simple geometric arguments.Comment: LaTeX file. 8 pages, 3 EPS pictures. New version contains
calculations of the energy of formation of the defects with model clusters of
different size
A priori collaboration in population imaging: The Uniform Neuro-Imaging of Virchow-Robin Spaces Enlargement consortium
Introduction: Virchow-Robin spaces (VRS), or perivascular spaces, are compartments of interstitial fluid enclosing cerebral blood vessels and are potential imaging markers of various underlying brain pathologies. Despite a growing interest in the study of enlarged VRS, the heterogeneity in rating and quantification methods combined with small sample sizes have so far hampered advancement in the field. Methods: The Uniform Neuro-Imaging of Virchow-Robin Spaces Enlargement (UNIVRSE) consortium was established with primary aims to harmonize rating and analysis (www.uconsortium.org). The UNIVRSE consortium brings together 13 (sub)cohorts from five countries, totaling 16,000 subjects and over 25,000 scans. Eight different magnetic resonance imaging protocols were used in the consortium. Results: VRS rating was harmonized using a validated protocol that was developed by the two founding members, with high reliability independent of scanner type, rater experience, or concomitant brain pathology. Initial analyses revealed risk factors for enlarged VRS including increased age, sex, high blood pressure, brain infarcts, and white matter lesions, but this varied by brain region. Discussion: Early collaborative efforts between cohort studies with respect to data harmonization and joint analyses can advance the field of population (neuro)imaging. The UNIVRSE consortium will focus efforts on other potential correlates of enlarged VRS, including genetics, cognition, stroke, and dementia
Origin and Evolution of Saturn's Ring System
The origin and long-term evolution of Saturn's rings is still an unsolved
problem in modern planetary science. In this chapter we review the current
state of our knowledge on this long-standing question for the main rings (A,
Cassini Division, B, C), the F Ring, and the diffuse rings (E and G). During
the Voyager era, models of evolutionary processes affecting the rings on long
time scales (erosion, viscous spreading, accretion, ballistic transport, etc.)
had suggested that Saturn's rings are not older than 100 My. In addition,
Saturn's large system of diffuse rings has been thought to be the result of
material loss from one or more of Saturn's satellites. In the Cassini era, high
spatial and spectral resolution data have allowed progress to be made on some
of these questions. Discoveries such as the ''propellers'' in the A ring, the
shape of ring-embedded moonlets, the clumps in the F Ring, and Enceladus' plume
provide new constraints on evolutionary processes in Saturn's rings. At the
same time, advances in numerical simulations over the last 20 years have opened
the way to realistic models of the rings's fine scale structure, and progress
in our understanding of the formation of the Solar System provides a
better-defined historical context in which to understand ring formation. All
these elements have important implications for the origin and long-term
evolution of Saturn's rings. They strengthen the idea that Saturn's rings are
very dynamical and rapidly evolving, while new arguments suggest that the rings
could be older than previously believed, provided that they are regularly
renewed. Key evolutionary processes, timescales and possible scenarios for the
rings's origin are reviewed in the light of tComment: Chapter 17 of the book ''Saturn After Cassini-Huygens'' Saturn from
Cassini-Huygens, Dougherty, M.K.; Esposito, L.W.; Krimigis, S.M. (Ed.) (2009)
537-57
An overview of research activities and achievement in Geotechnics from the Scottish Universities Geotechnics Network (SUGN)
ABSTRACT: Design of geotechnical systems is often challenging as it requires the understanding of complex soil behaviour and its influence on field-scale performance of geo-structures. To advance the scientific knowledge and the technological development in geotechnical engineering, a Scottish academic community, named Scottish Universities Geotechnics Network (SUGN), was established in 2001, composing of eight higher education institutions. The network gathers geotechnics researchers, including experimentalists as well as centrifuge, constitutive, and numerical modellers, to generate multiple synergies for building larger collaboration and wider research dissemination in and beyond Scotland. The paper will highlight the research excellence and leading work undertaken in SUGN emphasising some of the contribution to the geotechnical research community and some of the significant research outcomes. RÉSUMÉ: Conception de systèmes géotechniques est souvent difficile car elle nécessite la compréhension du comportement des sols complexes et son influence sur la performance échelle du champ de géo-structures. Pour faire avancer la connaissance scientifique et le développement technologique en ingénierie géotechnique, une communauté universitaire écossais, nommé écossais universités Géotechnique réseau (SUGN), a été créé en 2001, la composition des huit établissements d'enseignement supérieur. Le réseau réunit géotechnique chercheurs, y compris les expérimentateurs ainsi que centrifugeuse, constitutif, et les modélisateurs numériques, de générer des synergies multiples pour la construction de plus grande collaboration et une plus large diffusion de la recherche en Ecosse et au-delà. Le document mettra l'accent sur l'excellence de la recherche et de diriger le travail entrepris dans SUGN soulignant certains de la contribution à la communauté de recherche en géotechnique et certains des résultats importants de la recherche
Modeling of the condyle elements within a biomechanical knee model
The development of a computational multibody knee model able to capture some of the fundamental properties of the human knee articulation is presented. This desideratum is reached by including the kinetics of the real knee articulation. The research question is whether an accurate modeling of the condyle contact in the knee will lead to reproduction of the complex combination of flexion/extension, abduction/adduction and tibial rotation ob-served in the real knee? The model is composed by two anatomic segments, the tibia and the femur, whose characteristics are functions of the geometric and anatomic properties of the real bones. The biomechanical model characterization is developed under the framework of multibody systems methodologies using Cartesian coordinates. The type of approach used in the proposed knee model is the joint surface contact conditions between ellipsoids, represent-ing the two femoral condyles, and points, representing the tibial plateau and the menisci. These elements are closely fitted to the actual knee geometry. This task is undertaken by con-sidering a parameter optimization process to replicate experimental data published in the lit-erature, namely that by Lafortune and his co-workers in 1992. Then, kinematic data in the form of flexion/extension patterns are imposed on the model corresponding to the stance phase of the human gait. From the results obtained, by performing several computational simulations, it can be observed that the knee model approximates the average secondary mo-tion patterns observed in the literature. Because the literature reports considerable inter-individual differences in the secondary motion patterns, the knee model presented here is also used to check whether it is possible to reproduce the observed differences with reasonable variations of bone shape parameters. This task is accomplished by a parameter study, in which the main variables that define the geometry of condyles are taken into account. It was observed that the data reveal a difference in secondary kinematics of the knee in flexion ver-sus extension. The likely explanation for this fact is the elastic component of the secondary motions created by the combination of joint forces and soft tissue deformations. The proposed knee model is, therefore, used to investigate whether this observed behavior can be explained by reasonable elastic deformations of the points representing the menisci in the model.Fundação para a Ciência e a Tecnologia (FCT) - PROPAFE – Design and Development of a Patello-Femoral Prosthesis (PTDC/EME-PME/67687/2006), DACHOR - Multibody Dynamics
and Control of Hybrid Active Orthoses MIT-Pt/BSHHMS/0042/2008, BIOJOINTS -
Development of advanced biological joint models for human locomotion biomechanics
(PTDC/EME-PME/099764/2008)
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