1,065 research outputs found
Magnetically tunable Feshbach resonances in Li plus Yb 3PJ
We have investigated magnetically tunable Feshbach resonances arising from the interaction of Li(2S) with metastable Yb(3P2) and(3P0). ForYb(3P2), all the resonance features are strongly suppressed by inelastic collisions that produce Yb in its lower-lying 3P1 and 3P0 states. For Yb(3P0), sharp resonances exist but they are extremely narrow (widths less than 1 mG)
Sympathetic cooling of fluorine atoms with ultracold atomic hydrogen
We consider the prospect of using ultracold hydrogen atoms for sympathetic cooling of fluorine atoms to microkelvin temperatures. We carry out quantum-mechanical calculations on collisions between cold F and H atoms in magnetically trappable states and show that the ratio of elastic to inelastic cross sections remains high across a wide range of temperatures and magnetic fields. For F atoms initially in the spin-stretched state (2P3/2, f = mf = +2), sympathetic cooling appears likely to succeed from starting temperatures around 1 K or even higher. This occurs because inelastic collisions are suppressed by p-wave and d-wave barriers that are 600 mK and 3.2 K high, respectively. In combination with recent results on H + NH and H + OH collisions [M. L. González-Martínez and J. M. Hutson, Phys. Rev. Lett. 111, 203004 (2013)], this establishes ultracold H atoms as a very promising and versatile coolant for atoms and molecules that cannot be laser-cooled
Fatty acid composition of Mytilus galloprovincialis larvae fed on different micoralgal diets: effect on larval growth and survival.
The influence of dietary essential fatty acid on bivalve larval growth and survival has been reported by several authors. The objectives of the current research were (1) to describe fatty acid composition of Mytilus galloprovincialis D-larvae and (2) to investigate the influence of algal lipid composition on larval growth and survival. Larvae were fed with two diets, A (Tetraselmis suecica + Isochrisis galbana) and B (Tetraselmis suecica + Chaetoceros sp). After fifteen days the larval growth was significantly higher with diet B than with diet A. The survival was also different, being 28% in diet A and 22.4 % in diet B. The percentages of veliger, pediveliger and amorphous larvae were higher in group A than in B, while in the latter there were not amorphous larvae and the 21 % were postlarvae. So, the microalgae Chaetoceros sp seems to enhance larvae growth and development. The difference in diet also produced changes in fatty acid profiles being the most important change ones (1) the increase of 14:0 in both groups, (2) 16:0 decreased in group A but it increased in group B and (3) total MUFA showed higher levels in both trials. Total PUFA n-6 level was higher in group A due to the 18:2n-6 increase. Arachidonic acid level was augmented with both diets. EPA level diminished in group A but it augmented in group B, DHA behaviour was opposite, increasing in group A but decreasing in group B. This is due to the high level of EPA in Chaetoceros sp and DHA in Isochrysis galbana (Fernández-Reiriz et al., 2006). These results do not coincide with other studies which suggest that DHA is a key requirement for larval development and growth of other bivalve species (Caers et al., 1999). In our case diet rich in EPA seems to be better in mussel larva culture than the diet rich in DHA. This work was supported by Interreg Project 0251_ECOAQUA_5_E, financed by the EDRF (European Regional Development Fund). www.juntadeandalucia.es/agriculturaypesca/ifapa/ecoaqua.
La influencia de la composición en ácidos grasos de la dieta ha sido estudiada por diversos autores. Los objetivos de este trabajo fuero (1) describir la composición en ácidos grasos de las larvas D de Mytilus galloprovincialis y (2) investigar la influencia de la composición lipídica de las microalgas en el crecimiento y supervivencia larvario. Las larvas se fueron alimentadas con dos dietas,A (Tetraselmis suecica + Isochrisis galbana) y B (Tetraselmis suecica + Chaetoceros sp). Tras quince días el crecimiento larvario fue significativamente mayor con la dieta B que con la dieta A. La supervivencia también fue diferente, siendo 28 % en la dieta A y 22.4% en la dieta B. El porcentaje de las larvas veliger, pediveliger y amorfas fue mayor en A que en B, mientras que en éste no hubo amorfas y el 21 % fueron postlarvas. Por lo tanto la microalga Chaetoceros sp mejora el cultivo larvario. La diferencia en la dieta también produjo cambios en el perfil de ácidos grasos siendo los más importantes (1) el incremento del 14:0 en ambos grupos, (2) el 16:0 decreció en el grupo A pero aumentó en el B y (3) el total de monoinsaturados mostró mayores valores en ambos grupos. El total de PUFA n-6 fue mayor en el grupo A debido al incremento de 18:2n-6. El nivel de ácido araquidónico aumentó en ambos grupos. El nivel de EPA disminuyó en el grupo A pero aumentó en el grupo B, el comportamiento del DHA fue el contrario, incrementando en el grupo A y disminuyendo en el B. Esto fue debido al alto nivel de EPA en Chaetoceros sp y DHA en Isochrysis galbana (Fernández-Reiriz et al., 2006). Estos resultados no coinciden con otros estudios que sugieren que el DHA es un requerimiento clave para el desarrollo y crecimiento larvarios de otras especies de bivalvos (Caers et al., 1999). En nuestro caso la dieta rica en EPA parece ser mejor para el cultivo larvario de mejillones que la dieta rica en DHA. Este trabajo fue apoyado por el proyecto Interreg 0251_ECOAQUA_5_E, financiado por el FEDER (Fondo Europeo de Desarrollo Regional). www.juntadeandalucia.es/agriculturaypesca/ifapa/ecoaqua.</p
Lie point symmetries for generalised Fisher's equations describing tumour dynamics
A huge variety of phenomena are governed by ordinary differential equations (ODEs) and partial differential equations (PDEs). However, there is no general method to solve them. Obtaining solutions for differential equations is one of the greatest problem for both applied mathematics and physics. Multiple integration methods have been developed to the day to solve particular types of differential equations, specially those focused on physical or biological phenomena. In this work, we review several applications of the Lie method to obtain solutions of reaction-diffusion equations describing cell dynamics and tumour invasion.We would like to acknowledge group FQM-201 from Junta de Andalucia. We also would like to acknowledge Profs. Rita Tracina and Mariano Torrisi from the University of Catania (Italy) and Victor M. Perez Garcia from the University of Castilla-La Mancha (Spain) for discussions. This work was partially supported by the Fundacion Espanola para la Ciencia y la Tecnologia [UCA PR214], the Asociacion Pablo Ugarte (APU, Spain) and Inversion Territorial Integrada de la Provincia de Cadiz [ITI-0038-2019]
Las Comunidades de Macroparasitos del Mero, Epinephelus morio (Pisces: Serranidae), en la Peninsula de Yucatan, Mexico
Critical velocity in kink-defect interaction models: rigorous results
In this work we study a model of interaction of kinks of the sine-Gordon equation with a weak defect. We obtain rigorous results concerning the so-called critical velocity derived in [7] by a geometric approach. More specifically, we prove that a heteroclinic orbit in the energy level 0 of a 2-dof Hamiltonian is destroyed giving rise to heteroclinic connections between certain elements (at infinity) for exponentially small (in e) energy levels. In this setting Melnikov theory does not apply because there are exponentially small phenomena.Peer ReviewedPostprint (published version
Crystal structure of the FAD-containing ferredoxin-NADP+ reductase from the plant pathogen Xanthomonas axonopodis pv. citri
We have solved the structure of ferredoxin-NADP(H) reductase, FPR, from the plant pathogen Xanthomonas axonopodis pv. citri, responsible for citrus canker, at a resolution of 1.5¿Å. This structure reveals differences in the mobility of specific loops when compared to other FPRs, probably unrelated to the hydride transfer process, which contributes to explaining the structural and functional divergence between the subclass I FPRs. Interactions of the C-terminus of the enzyme with the phosphoadenosine of the cofactor FAD limit its mobility, thus affecting the entrance of nicotinamide into the active site. This structure opens the possibility of rationally designing drugs against the X. axonopodis pv. citri phytopathogen
Aprovechamiento de residuos de la industria textil para la preparación de telas de carbón activo.
Los residuos generados por la industria textil en España se han cuantificado sobre unas 30.000 Toneladas durante los últimos años. Debido al gran volumen de almacenamiento que necesitan estos residuos, así como la problemática generada por la disponibilidad geográfica, hacen que sea de gran interés el estudio del aprovechamiento de estos materiales, siendo de gran importancia la obtención de materiales carbonosos que poseen originariamente una estructura fibrilar en forma continua, cuya forma presenta características muy interesantes para distintas aplicaciones. En el presente trabajo se muestran los resultados de preparación y caracterización de materiales carbonosos a partir de residuos de la industria textil, usando como materia prima tejidos de algodón, los cuales se activarán químicamente con H3PO4. Las telas de carbón activo obtenidas serán usadas para testar su aplicación como adsorbentes y como materiales para almacenamiento de energía.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
Maritime studies and shipping bussines: a trend research on education programs
The Schools of Maritime Engineering & Business of the Spanish Universities forms the future professionals of the Spanish Merchant Marine who will sail the seven seas transporting goods in all its various forms. This remains a very important profession however, the importance of these activities it is not usually well known by the rest of the society not directly involved with the maritime world. The professions have been evolving, and the maritime job is not an exception. The marine professionals had opened new gates to develop new activities in other di erent positions which traditionally were busy by others carriers, for example, shipping companies. However, training in this sense is lacking, nautical students in most of the cases are not trained and specialized in this regard. The idea of this research paper is to quantify and identify the needs for the training and propose a training plan according to current needs in this area. The methodology of this work, has consisted of comparative analysis based on the results obtained from di erent surveys. The first survey has been conducted in several schools of nautical and maritime studies, considering the di erent levels existent at training programs, perception from students in relation to major weaknesses and missing elements. The second survey focused on experts in shipping & maritime logistics considering their experience from the trainee students with the objective to identify the core skills that will be required from a professional point of view. The results of both surveys have been combined, performing a comparative analysis in order to define a curriculum model that should cover the academic and business abilities gaps identified during the study
Intra-Abdominal Pressure as a Marker of Enteral Nutrition Intolerance in Critically Ill Patients. The PIANE Study
To determine whether elevated intra-abdominal pressure (IAP) is associated with a higher rate of enteral nutrition-related gastrointestinal (GI) complications; to assess the value of IAP as a predictor of enteral nutrition (EN) intolerance. Intensive Care Unit (ICU) patients on mechanical ventilation requiring at least 5 days of EN were recruited for a prospective, observational, non-interventional, multicenter study. EN was performed and GI complications were managed with an established protocol. IAP was determined via a urinary catheter. Patients who developed any GI complications were considered as presenting EN intolerance. Variables related to EN, IAP and GI complications were monitored daily. Statistical analysis compared patients without GI complications (group A) vs. GI complications (group B). 247 patients were recruited from 28 participating ICUs (group A: 119, group B: 128). No differences between groups were recorded. Patients in group B (p < 0.001) spent more days on EN (8.1 ± 8.4 vs. 18.1 ± 13.7), on mechanical ventilation (8.0 ± 7.7 vs. 19.3 ± 14.9) and in the ICU (12.3 ± 11.4 vs. 24.8 ± 17.5). IAP prior to the GI complication was (14.3 ± 3.1 vs. 15.8 ± 4.8) (p < 0.003). The best IAP value identified for EN intolerance was 14 mmHg but it had low sensitivity and specificity. Although a higher IAP was associated with EN intolerance, IAP alone did not emerge as a good predictor of EN intolerance in critically ill patients
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