Receptividad estigmática en manzano (Malus x pumila, Mill.)

Panel(S5-P7) presentado en la Reunión de la Sociedad Española de Fisiología Vegetal (SEFV) (18ª. Zaragoza. 8-11 septiembre 2009).La receptividad estigmática es un parámetro floral que determina el tiempo en el que los estigmas mantienen la capacidad de generar un ambiente propicio para la germinación de los granos de polen. Este parámetro afecta directamente al éxito reproductivo y tiene especial relevancia en especies cultivadas en las que tiene una clara repercusión en la cosecha. A pesar de su relevancia, se desconocen los factores determinantes de la receptividad estigmática. En este trabajo se estudia la receptividad estigmática en manzano (Malus xpumila, Mill.). Para ello se ha evaluado el momento en que se adquiere la receptividad estigmática observando los cambios en los tejidos del estigma, así como el comportamiento del polen tras su llegada a la superficie estigmática. Con este propósito se han realizado fijaciones secuenciales de los estilos para la observación de cambios histoquímicos en diversos estados de desarrollo previos a la apertura floral. Del mismo modo, se han observado cambios producidos por la polinización en las células estigmáticas. Finalmente, y tras observaciones secuenciales en el tiempo, se ha evaluado el comportamiento de los granos de polen en el estigma tras la polinización. Los resultados permiten establecer el marco espacio temporal en el cual las flores del manzano son receptivas, así como los cambios en las células que acompañan la adquisición de la receptividad y apoyan la interacción polen-estigma.Este estudio ha sido financiado, con CICYT AGL2006-13529-C02-O1, por una beca FPI a Juan M. Losada y por el Grupo de Excelencia de Aragón A-43.Peer reviewe

The influence of the progamic phase for fruiting in the apple tree

24 p., 12 fig., 6 tabl. The definitive version is available at http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1744-7348Final fruit production is the result of a number of processes, over which several environmental circumstances interact. But it is often difficult to disentangle the part played by each of these factors in the final crop. The aim of this work is to evaluate the influence of the progamic phase for fruiting in the apple tree. For this purpose we track back the process that goes from flower to fruit, identifying the inflection points where the final crop is reduced. We evaluate early versus late fruit development, pollination versus non-pollination, and the effect of the progamic phase that goes from pollination to fertilization. From flowers to fruits 15 weeks elapsed, but the final fruit set settled 8 weeks after flowering, and the main flower–fruit drop occurred 3–4 weeks after flowering. Differences between dropped fruits and those that remained in the tree emerged earlier, and the onset of fruiting started 7 days after pollination. This time was coincident with the time lapse of the progamic phase. These results show that fruiting gets established well ahead of cropping, but also that the progamic phase is the main determinant of the final fruit set in apple trees.This work was supported by Ministerio de Ciencia e Innovación (MICINN)-FEDER[AGL2006-13529-C02-01, AGL 12621-C02-01 and AGL 2012–40239] and Gobierno de Aragón [group A43]. J. M. L. was supported by a FPI fellowship [BES-2007-16059] from the MICINN.Peer reviewe

Do trade and financial linkages foster business cycle synchronization in a small economy?

We estimate a system of equations to analyze whether bilateral trade and financial linkages influence business cycle synchronization directly and/or indirectly. Our paper builds upon the existing literature by using bilateral trade and financial flows for a small, open economy (Spain) as benchmark for the results, instead of the US as generally done in the literature. We find that both the similarity of productive structure and trade links promote the synchronization of cycles. However, bilateral financial links are inversely related to the co movement of output. This might point to financial integration allowing an easiertransfer of resources between two economies, which could enable their decoupling, as predicted by a standard model of international business cycles. Both the effects of trade and financial links on output synchronization are statistically significant and economically relevan

Site Selectivity for CO Adsorption and Stripping on Stepped and Kinked Platinum Surfaces in Alkaline Medium

This work reports experimental evidence that the adsorption of CO on Pt surfaces composed by (111) terraces and steps and/or kinks in alkaline media occurs faster on sites with (100) symmetry, followed by (110) sites. On the other hand, the (111) terrace has the lowest adsorption rate. CO electrooxidation demonstrates the existence of a close relationship between the preferential site CO occupancy and the peak multiplicity observed in CO stripping voltammetry. For the stepped Pt(554) and Pt(544) and kinked Pt(875) single crystal surfaces, the CO stripping process takes place at high potentials (0.80 V vs RHE) when only the (110) or (100) step sites are blocked by CO. However, when the terrace sites with (111) symmetry are fully occupied, new CO stripping peaks appear at lower potentials (<0.68 V vs RHE). For all surfaces, it is observed that the first released sites after partial CO oxidation are (111) terrace sites, followed by the step (110) sites and sites with (100) symmetry. The results of partial CO oxidation suggest that the diffusion of adsorbed CO from sites with (110) or (100) symmetry toward unoccupied (111) terrace sites is negligible. However, CO diffusion from terrace sites to step or kink sites cannot be discarded during the growth of the adsorbed CO adlayer, because of the preferential site occupancy for these latter sites. Due to the fact that the CO oxidation process on stepped Pt surfaces in alkaline media occurs at different potentials on different sites, the activation energies for CO oxidation on the different sites have been estimated. The results for full CO coverage and CO decorated stepped surfaces are in good agreement, indicating that the oxidation of CO on the different sites is not coupled. In the absence of CO on terrace sites, in situ FTIR spectroscopy shows that CO molecules on the (110) step sites are essentially linearly bonded, while on the (100) step sites both linearly and bridge bonded CO are observed. The comparison of these spectra with those obtained when a full coverage is attained shows that the band frequencies for CO on step sites are highly coupled with those on the terrace sites.M.J.S.F. would like to thank CNPq, Brazil, for financial support for his postdoctoral stay at Universidad de Alicante. This work has been financially supported by the MICINN (Spain) (project CTQ2010-16271) and Generalitat Valenciana (project PROMETEO/2009/045, -FEDER)

Anatomical Study of the Canine Limbs in Relation to External Skeletal Fixation: Introduction and Delimitation of Safe, Hazardous and Unsafe Corridors

An anatomical study of the canine limbs was carried out in order to identify, locate and measure the extent of the safe, hazardous and unsafe corridors for pin insertion for the use of external skeletal fixation. Topographical dissections and cross-sections of fresh anatomical specimens of canine limbs were used to localise important neurovascular structures and musculotendinous units and to measure the extent of the corridors. Safe corridors for external skeletal fixator pin insertion are clearly present in the eccentric bones of the canine lower limbs. Although no clear safe passages were identified in concentric bones of the upper limb, hazardous areas and lines are described as the safest for application of external fixation frames. The feasibility of the application of different fixator configurations through safe areas in the canine appendicular long bones is discussed. Some guidelines are given in order to allow the orthopaedic surgeon to follow sound anatomical principles of fixator application and to reduce the incidence of some avoidable complications

Identificación Robusta de Sistemas no Lineales mediante Algoritmos Evolutivos

[EN] The identification process of the parameters of a nominal model and its uncertainty, when it is used for Robust Control, is known as Parametric Robust Identification (RI). A possible approach to RI, which is appropriate when noise statistical properties unknown and/or model error invalidate statistical approaches, is the deterministic one (Set Membership Estimation). This deterministic approach assumes that identification error (IE), differences between the simulated outputs of the model and the measured outputs of the process, although unknown, will be bounded. Therefore, the objective is to estimate the parameters set of a model which keeps the identification error bounded by a certain norm and bound. This set is known as the feasible parameter set (FPS). For linear in their parameters models, the FPS is, if it exists, a convex polytope. In nonlinear models, the polytope can be non-convex even disjoint. In this thesis a RI methodology, which permits to estimate any kind of FPS in nonlinear models when IE is bounded by several norms simultaneously, is presented. This methodology converts the RI problem into a multimodal optimization problem with optimal global infinities, which constitute the FPS. For its optimization a specific evolutionary algorithm e-GA has been developed, to characterize the FPS by means of a discrete set of models FPS^* adequately distributed along the FPS. The methodology comes accompanied by a procedure that makes easy the determination of bounds, associated to the norms of the IE, in order to guarantee an FPS\neq\emptyset. For that, the Pareto Front information, which is obtained by means of minimization norms of the IE in a multobjective context is used. To solve the multobjective problem an evolutionary algorithm e-MOGA has been developed. In addition, a nominal model of restricted interpolated projection which belongs to the FPS is proposed. It is optimal in both identification and estimation errors in the parameter space. The RI of three nonlinear models, with real data, is presented as application examples of the proposed methodology: a thermal process, a model which shows the blockage that produces a given drug on the ionic currents of a cardiac cell and a greenhouse climate model (temperature and humidity) with roses hydroponic crop.[ES] Al proceso de identificación de los parámetros de un modelo nominal y su incertidumbre para su utilización en Control Robusto se le conoce como Identificación Robusta Paramétrica (IR). Un posible enfoque para abordar la IR, que resulta apropiado cuando el desconocimiento de las propiedades estadísticas del ruido y/o la dinámica no modelada invalidan los enfoques estocásticos, es el determinístico (Set Membership Estimation). Este enfoque asume que el error de identificación (EI), diferencia entre las salidas medidas de proceso y las simuladas del modelo, aunque es desconocido, está acotado. De ahí que, bajo este enfoque, se persiga la determinación del conjunto de parámetros que consiguen mantener el EI acotado para una determinada norma y cota. Dicho conjunto es conocido como el conjunto de parámetros factibles (FPS). Cuando el modelo es lineal respecto de sus parámetros, el FPS, si existe, es un politopo convexo. En modelos no lineales dicho politopo puede ser no convexo e incluso inconexo. En esta tesis se presenta una metodología de IR que permite determinar FPS, de cualquier tipo, en modelos no lineales cualesquiera, acotando el EI simultáneamente mediante varias normas. La metodología transforma el problema de IR en un problema de optimización multimodal con infinitos óptimos globales, los cuales constituyen el FPS. Para su optimización se ha desarrollado un algoritmo evolutivo (EA) específico e-GA, que caracteriza el FPS mediante un conjunto discreto de modelos FPS* adecuadamente distribuido a lo largo del FPS. La metodología viene acompañada de un procedimiento que facilita la determinación de las cotas, asociadas a las normas que acotan el EI, para asegurar que FPS no se aun conjutno vacío. Para ello, se utiliza la información que genera el frente de Pareto resultante de la minimización simultánea de las normas mediante una optimización multiobjetivo.Para resolver este problema de optimización se ha desarrollado el algoritmo evolutivo e-MOGA. Adicionalmente, se propone como modelo nominal un modelo de proyección interpolada restringida que, pertenenciendo al FPS, resulta óptimo respecto del error de identificación y respecto del error de estimación en el espacio de parámetros. Como ejemplos de aplicación de la metodología propuesta se presenta la IR, con datos reales, de los parámetros de tres modelos no lineales: un sistema térmico, un modelo que refleja el bloqueo que produce un determinado fármaco sobre las corrientes iónicas de una célula cardíaca y el modelo climático de un invernadero (temperatura y humedad) con cultivo hidropónico de rosas.[CA] Al procés d'identificació dels paràmetres d'un model nominal i la seua incertesa per a la seua utilització en Control Robust se'l coneix com a Identificació Robusta Paramètrica (IR). Un possible enfocament per a abordar l'IR, que resulta apropiat quan el desconeixement de les propietats estadístiques del soroll i/o la dinàmica no modelada invaliden els enfocaments estocàstics, és el determinístic (Set Membership Estimation). Aquest enfocament assumeix que l'error d'identificació (EI), diferència entre les eixides mesurades del procés i les simulades del model, encara que és desconegut, està acotat. Davall aquest enfocament, es persegueix la determinació del conjunt de paràmetres que aconsegueixen mantenir l'EI acotat per a una determinada norma i cota. Dit conjunt és conegut com el conjunt de paràmetres factibles (FPS). Quan el model és lineal respecte dels seus paràmetres, el FPS, si existeix, és un politop convex. En models no lineals dit politop pot ser no convex i fins i tot inconnex. En aquesta tesi es presenta una metodologia d'IR que permet determinar FPS, de qualsevol tipus, en models no lineals qualsevol, acotant l'EI simultàniament mitjançant diverses normes. La metodologia transforma el problema d'IR en un problema d'optimització multimodal amb infinits òptims globals, els quals constitueixen el FPS. Per a la seua optimització s'ha desenvolupat un algoritme evolutiu (EA) específic e-GA, que caracteritza el FPS mitjançant un conjunt discret de models FPS^* adequadament distribuït al llarg del FPS. La metodologia ve acompanyada d'un procediment que facilita la determinació de les cotes, associades a les normes que acoten l'EI, per a assegurar que FPS\neq\emptyset. Per a això, s'utilitza la informació que genera el front de Pareto resultant de la minimització simultània de les normes mitjançant una optimització multiobjetiu. Per a la resoldre, el problema multiobjectiu s'ha desenvolupat l'algoritme evolutiu e-MOGA. Addicionalment, es proposa com a model nominal un model de projecció interpolada restringida que, pertanyent al FPS, resulta òptim respecte de l'error d'identificació i respecte de l'error de estimació en l'espai de paràmetres. Com a exemples d'aplicació de la metodologia proposada es presenta l'IR, amb dades reals, dels paràmetres de tres models no lineals: un sistema tèrmic, un model que reflecteix el bloqueig que produeix un determinat fàrmac sobre els corrents iònics d'una cèl·lula cardíaca i el model climàtic d'un hivernacle (temperatura i humitat) amb cultiu hidropònic de roses.Herrero Durá, JM. (2006). Identificación Robusta de Sistemas no Lineales mediante Algoritmos Evolutivos [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/13139

The cyl Genes Reveal the Biosynthetic and Evolutionary Origins of the Group B Streptococcus Hemolytic Lipid, Granadaene

Group B Streptococcus (GBS) is a b-hemolytic, Gram-positive bacterium that commonly colonizes the female lower genital tract and is associated with fetal injury, preterm birth, spontaneous abortion, and neonatal infections. A major factor promoting GBS virulence is the b-hemolysin/cytolysin, which is cytotoxic to several host cells. We recently showed that the ornithine rhamnolipid pigment, Granadaene, produced by the gene products of the cyl operon, is hemolytic. Here, we demonstrate that heterologous expression of the GBS cyl operon conferred hemolysis, pigmentation, and cytoxicity to Lactococcus lactis, a model non-hemolytic Gram-positive bacterium. Similarly, pigment purified from L. lactis is hemolytic, cytolytic, and identical in structure to Granadaene extracted from GBS, indicating the cyl operon is sufficient for Granadaene production in a heterologous host. Using a systematic survey of phyletic patterns and contextual associations of the cyl genes, we identify homologs of the cyl operon in physiologically diverse Gram-positive bacteria and propose undescribed functions of cyl gene products. Together, these findings bring greater understanding to the biosynthesis and evolutionary foundations of a key GBS virulence factor and suggest that such potentially toxic lipids may be encoded by other bacteria.This work was supported by funding from the National Institutes of Health grants R01AI112619, R01AI33976, R01AI00989, and R21AI125907 to LR. The NIH training grant T32AI07509 (PI: Lee Ann Campbell) supported CW. LI and LA were supported by intramural funds from NLM, NIH