186 research outputs found
Geometric structures on loop and path spaces
Is is known that the loop space associated to a Riemannian manifold admits a
quasi-symplectic structure. This article shows that this structure is not
likely to recover the underlying Riemannian metric by proving a result that is
a strong indication of the "almost" independence of the quasi-symplectic
structure with respect to the metric. Finally conditions to have contact
structures on these spaces are studied.Comment: Final version. To appear in Proceedings of Math. Sci. Indian Academy
of Science
First record of Oligochoerus limnophilus (Acoela, Acoelomorpha) from British waters
Primer registro de Oligochoerus limnophilus (Acoela, Acoelomorpha) en aguas británicas
Informamos de la existencia de poblaciones del acelo Oligochoerus limnophilus (Acoelomorpha) en la islas Británicas sobre la base de los especímenes capturados en el río Támesis (también conocido localmente como río Isis) a su paso por Oxford, Inglaterra, ampliando así considerablemente el área de distribución de la especie, restringida hasta ahora al continente europeo. La información gráfica que aportamos, imágenes de especímenes vivos y proyecciones CLSM de estructuras informativas seleccionadas por su valor sistemático, corrobora su estrecha relación con el género Convoluta Ørsted, 1843.We report the occurrence of the acoel Oligochoerus limnophilus (Acoelomorpha) from the British Islands, based on specimens captured in the river Thames (locally known as the river Isis) in Oxford, England, thereby considerably widening the distributional range of the species that had formerly been reported only from continental Europe. We further present live images and CLSM-projections of systematically informative structures that corroborate a close relationship with the genus Convoluta Ørsted, 1843.Primer registre d'Oligochoerus limnophilus (Acoela, Acoelomorpha) en aigües britàniques
Informem de l'existència de poblacions de l'acel Oligochoerus limnophilus (Acoelomorpha) a les illes Britàniques sobre la base dels espècimens capturats al riu Tàmesi (també conegut localment com a riu Isis) al pas per Oxford, Anglaterra, amb la qual cosa ampliem considerablement l'àrea de distribució de l'espècie, restringida fins ara al continent europeu. La informació gràfica que aportem, imatges d'espècimens vius i projeccions CLSM d'estructures informatives seleccionades pel seu valor sistemàtic, corrobora l'estreta relació amb el gènere Convoluta Ørsted, 1843
Memoria sobre el estado y situación política en que se hallaba el reino de Nueva España en agosto de 1823
Copia digital. Madrid : Ministerio de Cultura. Subdirección General de Coordinación Bibliotecaria, 200
Evolutionary Analysis of Mitogenomes from Parasitic and Free-Living Flatworms
Copyright: © 2015 Solà et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. The attached file is the published version of the article
Optimizing the production of the biosurfactant lichenysin and its application in biofilm control
Aims: Apply response surface methodology (RSM) to develop and optimize an economical medium for lichenysin production, which is a surfactant produced by Bacillus licheniformis and evaluate the application of lichenysin in the prevention and disruption of pathogenic micro-organism biofilm that creates health problems in the food industry and hospitals. Results: An economical medium containing molasses was optimized to enhance lichenysin production by RSM. A production of 3.2 g l 1 of lichenysin was achieved with an optimum medium containing 107.82 g l 1 of molasses, 6.47 g l 1 of NaNO3 and 9.7 g l 1 of K2HPO4/KH2PO4, in which molasses and phosphate salts had a significant effect on biosurfactant production. Lichenysin was effectively applied in a surface pre-treatment to avoid microbial biofilm development of methicillin-resistant Staphylococcus aureus (MRSA) (68.73%) and Candida albicans (74.35%), with ED50 values of 8.3 and 17.2 lg ml 1 respectively. It was also very efficient in a surface posttreatment to remove biofilms of MRSA (55.74%) and Yersinia enterocolitica (51.51%), with an ED50 of 2.79 and 4.09 lg ml 1 respectively. Conclusions: Lichenysin was found to have notable anti-adhesion activity, being able to prevent and eliminate the biofilm formation by pathogenic strains associated with foodborne illness. This new medium resulted in a fourfold increase in production compared with the nonoptimized medium. Significance and Impact of the Study: Molasses can be regarded as a useful resource for biotechnological applications, such as the production of lichenysin. The use of agro-industrial substrates has an important role in the sustainable and competitive development of several industrial sectors, as well as in industrial residues management. Additionally, lichenysin is particularly effective in preventing biofilm formation by strains problematic for the food industry and in the hospital environment. Lichenysin also efficiently disrupts biofilm
Microestructure and mechanical properties of biomorphic SiC obtained from eucalyptus
El desarrollo de materiales cerámicos con una estructura de tipo celular, similar a la del hueso o la madera, ha sido una
cuestión que ha suscitado un gran interés en los últimos años. Su atractivo se debe al hecho de poseer una estructura porosa
altamente interconectada de baja densidad, perfeccionada por la evolución.
En el caso del SiC biomórfico (bio-SiC) el proceso de fabricación es sencillo: se piroliza una pieza de madera y a continuación
se inyecta con silicio líquido, el material así obtenido es un compuesto Si/SiC en el que el SiC mimetiza la estructura de la
madera original.
En este trabajo se estudian las propiedades mecánicas del SiC biomórfico fabricado a partir de eucalipto (madera dura con
una distribución bimodal de poros). Se ha estudiado el comportamiento mecánico del mismo (resistencia a compresión,
resistencia a flexión, tenacidad de fractura y módulo de elasticidad) entre 25 y 1350 o
C. Asimismo, se discute la relación entre
el comportamiento mecánico del material y su microestructura.The development of cellular ceramics with a biological structure, like bones and wood, has been a matter of interest in
recent years. A low density highly interconnected structure, perfected by evolution, rises as the principal advantage of these
materials.
In the case of biomimetic SiC (biomorphic SiC, or bioSiC), the fabrication process technique is quite simple: a piece of wood
is pyrolysed and is infiltrated with molten silicon after, the final product is a composite Si/SiC, which replicates the wood
anisotropic microstructure
This work focus on the mechanical properties of bioSiC fabricated using eucalyptus wood as precursor (hard wood with
a bimodal channel distribution). It has been studied the mechanical behavior of this bioSiC (compression strength, flexure
strength, fracture toughness and elastic modulus) between 25 and 1350 o
C. It is also discussed the relationship between
mechanical behavior of the material and its microstructure
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