668 research outputs found
Cellulose is degraded during phloem necrosis of Hevea brasiliensis
La nécrose du phloème d'Hévéa est une grave maladie répandue dans les plantations ouest-africaines. A l'échelle ultrastructurale, l'altération des parois cellulaires est la modification la plus fréquemment observée. Une étude cytochimique a été entreprise dans le but de mieux comprendre les mécanismes de la dégradation de la cellulose des parois. Les observations microscopiques ont également montré la présence de vésicules paramurales et de dépôts le long des parois dans les espaces périplasmiques, suggérant la participation directe, ou indirecte, de microorganismes à la nécrose du phloème d'Hévéa. (D'après résumé d'auteur
New method for extracting quasi-bound states from the continuum
A new parameter-free method is proposed for treatment of single-particle
resonances in the real-energy continuum shell model. This method yields
quasi-bound states embedded in the continuum which provide a natural
generalization of weakly bound single-particle states.Comment: 22 pages, 10 figure
Plane waves with negative phase velocity in Faraday chiral mediums
The propagation of plane waves in a Faraday chiral medium is investigated.
Conditions for the phase velocity to be directed opposite to the direction of
power flow are derived for propagation in an arbitrary direction; simplified
conditions which apply to propagation parallel to the distinguished axis are
also established. These negative phase-velocity conditions are explored
numerically using a representative Faraday chiral medium, arising from the
homogenization of an isotropic chiral medium and a magnetically biased ferrite.
It is demonstrated that the phase velocity may be directed opposite to power
flow, provided that the gyrotropic parameter of the ferrite component medium is
sufficiently large compared with the corresponding nongyrotropic permeability
parameters.Comment: accepted for publication in Phys. Rev.
Finite-Dimensional Bicomplex Hilbert Spaces
This paper is a detailed study of finite-dimensional modules defined on
bicomplex numbers. A number of results are proved on bicomplex square matrices,
linear operators, orthogonal bases, self-adjoint operators and Hilbert spaces,
including the spectral decomposition theorem. Applications to concepts relevant
to quantum mechanics, like the evolution operator, are pointed out.Comment: 21 page
Inverse determination of transient local heat transfer in a liquid microlayer
La détermination de la répartition locale de la température de surface dans une micro-couche liquide est très complexe. Cet article présente les résultats d'analyse inverse des mesures sur le refroidissement d'un disque chauffé par un minijet d'eau réparti sur la surface d'échange sous la forme d'une micro-couche liquide. La distribution locale des densités de flux surfaciques est obtenue par résolution du problème inverse de conduction de la chaleur en transitoire
Searching for biomarkers of aneurysmal disease
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Key factors in children's competence to consent to clinical research
Background: Although law is established on a strong presumption that persons younger than a certain age are not competent to consent, statutory age limits for asking children's consent to clinical research differ widely internationally. From a clinical perspective, competence is assumed to involve many factors including the developmental stage, the influence of parents and peers, and life experience. We examined potential determining factors for children's competence to consent to clinical research and to what extent they explain the variation in competence judgments. Methods: From January 1, 2012 through January 1, 2014, pediatric patients aged 6 to 18 years, eligible for clinical research studies were enrolled prospectively at various in- and outpatient pediatric departments. Children's competence to consent was assessed by MacArthur Competence Assessment Tool for Clinical Research. Potential determining child variables included age, gender, intelligence, disease experience, ethnicity and socio-economic status (SES). We used logistic regression analysis and change in explained variance in competence judgments to quantify the contribution of a child variable to the total explained variance. Contextual factors included risk and complexity of the decision to participate, parental competence judgment and the child's or parents decision to participate. Results: Out of 209 eligible patients, 161 were included (mean age, 10.6 years, 47.2 % male). Age, SES, intelligence, ethnicity, complexity, parental competence judgment and trial participation were univariately associated with competence (P∈∈0.05). Conclusions: Age is the factor that explaines most of to the variance in children's competence to consent, followed by intelligence. Experience with disease did not affect competence in this study, nor did other variables. Clinical trial registration: Development and use of a standardized instrument for assessing children's competence to consent in drug trials: Are legally established age limits valid?, NTR3918
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