The bulbus arteriosus of the holocephalan heart

El resumen aparece en el Program & Abstracts of the 10th International Congress of Vertebrate Morphology, Barcelona 2013.Anatomical Record, Volume 296, Special Feature — 1: P-074.Previous work has shown that the outflow tract of the elasmobranch heart, namely the cardiac portion intercalated between the ventricle and the ventral aorta, does not consist of a single component, the conus arteriosus, as has classically been assumed, but two, the myocardial conus arteriosus and the non-myocardial bulbus arteriosus. From the evolutionary perspective, knowledge of the anatomy of the cardiac outflow tract of the holocephali is important, as they are the sister group of elasmobranchs. Our aim is to describe the cardiac outflow tract of four holocephalan species, two of them, Chimaera monstrosa and Hydrolagus affinis of the family Chimaeridae, and the other two, Harriotta raleighana and Rhinochimaera atlantica, of the family Rhinochimaeridae. The cardiac outflow tract of the four species consisted of a myocardial conus arteriosus, furnished with valves, and a bulbus arteriosus devoid of cardiac muscle. Both the bulbus and conus are tubular in shape. The length of the bulbus relative to the total length of the outflow tract is somewhat smaller in the rhinochimaerids (15%-19%) than in the chimaerids (19%-23%). The bulbus is covered by epicardium and is crossed by the main coronary artery trunks. Histologically, the bulbus is mainly composed of elastin and collagen, and, to a lesser extent, by smooth muscle. This suggests that in holocephalans, the bulbus actively helps to protect the gill vasculature from exposure to high-pressure pulses of blood. Our results prove that the bulbus arteriosus is common to chondrichthyans. In addition, they support the hypothesis that the cardiac outflow tract consisted of a conus arteriosus and a bulbus arteriosus from the beginning of the jawed vertebrate radiation, contributing to our understanding of the morphological changes that have occurred at the arterial pole of the heart in both actinopterygians and sarcopterygians.Proyecto CGL2010-16417/BOS; Fondos FEDE

MYOCARDIAL STRUCTURE AND VASCULARIZATION OF THE HEART VENTRICLE IN HOLOCEPHALI: IMPLICATIONS FOR HEART EVOLUTION

El resumen aparece en el Program & Abstracts of the 10th International Congress of Vertebrate Morphology, Barcelona 2013. Anatomical Record, Volume 296, Special Feature — 1: P-075.It has been classically assumed that the ventricle of the primitive vertebrate heart is composed of spongy myocardium, supplied exclusively by oxygen-poor, luminal blood. This idea is on two facts: (1) extant agnathans have a spongy ventricular myocardium, and (2) in avian and mammalian embryos, the formation of trabeculated myocardium precedes the appearance of compact myocardium. Recently, it has been proposed that, like elasmobranchs, the early gnathostomes possess a fully vascularised ventricle composed of mixed myocardium. We tested this idea by studying the structure and vascularisation of the ventricular myocardium in four holocephalan species of the families Chimaeridae and Rhinochimaeridae. Chimaera monstrosa, Hidrolagus affinis and Harriotta raleighana have a spongy myocardium covered by a thin layer of cardiac muscle. In H. raleighana, the compacta is reduced to an extremely fine rim. In all three species there is a well-developed coronary artery system consisting of subepicardial vessels which give off branches that penetrate the myocardial trabeculae. Rhinochimaera atlantica has no compacta and its ventricular coronary artery system is reduced to subepicardial vessels that do not enter the spongy layer. This report is the first to show that in wild living vertebrates, a coronary artery system supplying the whole myocardium exists in the absence of a well-developed compacta, which supports experimental work that shows that myocardial cell proliferation and coronary vascular growth rely on genetically separated programs. We conclude that the mixed ventricular myocardium is primitive for chondrichthyans, and that the lack of compacta in some holocephalans is a derived character. Moreover our results support the hypotheses that the mixed myocardium is the primitive condition in gnathostomes, and that the absence of a compacta in different actinopterygian taxa is the result of its repeated loss during evolution.Proyecto CGL2010-16417/BOS; Fondos FEDE

Polymeric foams as the matrix of voltammetric sensors for the detection of catechol, hydroquinone, and their mixtures

Producción CientíficaPorous electrodes based on polymethylmethacrylate and graphite foams (PMMA_G_F) have been developed and characterized. Such devices have been successfully used as voltammetric sensors to analyze catechol, hydroquinone, and their mixtures. The presence of pores induces important changes in the oxidation/reduction mechanism of catechol and hydroquinone with respect to the sensing properties observed in nonfoamed PMMA_graphite electrodes (PMMA_G). The electropolymerization processes of catechol or hydroquinone at the electrode surface observed using PMMA_G do not occur at the surface of the foamed PMM_G_F. In addition, the limits of detection observed in foamed electrodes are one order of magnitude lower than the observed in the nonfoamed electrodes. Moreover, foamed electrodes can be used to detect simultaneously both isomers and a remarkable increase in the electrocatalytic properties shown by the foamed samples, produces a decrease in the oxidation potential peak of catechol in presence of hydroquinone, from +0.7 V to +0.3 V. Peak currents increased linearly with concentration of catechol in presence of hydroquinone over the range of 0.37·10−3 M to 1.69·10−3 M with a limit of detection (LOD) of 0.27 mM. These effects demonstrate the advantages obtained by increasing the active surface by means of porous structures.Ministerio de Economía, Industria y Competitividad - Fondo Europeo de Desarrollo Regional (project AGL2015-67482-R)Junta de Castilla y Leon - Fondo Europeo de Desarrollo Regional (project VA-011U16

Anatomical, histochemical and immunohistochemical characterization of the outflow tract of ray hearts (Rajiformes; Chondrichthyes)

El resumen aparece en el Program & Abstracts of the 11th International Congress of Vertebrate Morphology, Washington DC 2016. Anatomical Record, Volume 299, Special Feature: 264.Recent work has shown that the cardiac outflow tract of sharks and chimaeras does not consist of a single myocardial component, the conus arteriosus, as classically accepted, but two, namely, the myocardial conus arteriosus and the non-myocardial bulbus arteriosus. However, the anatomical composition of the outflow tract of the batoid hearts remains unknown. The present study was designed to fill this gap. The material examined consisted of hearts of two species of rays, namely, the Mediterranean starry ray (Raja asterias) and sandy ray (Leucoraja circularis). They were studied using scanning electron microscopy, and histochemical and inmunohistochemical techniques. In both species, the outflow tract consists of two components, proximal and distal with regard to the ventricle. The proximal component is the conus arteriosus; it is characterized by the presence of compact myocardium in its wall and several transverse rows of pocket-shaped valves at its luminal side. Each valve consists of a leaflet and its supporting sinus. Histologically, the leaflet has two fibrosas, inner and outer, and a middle coat, the spongiosa. The distal component lacks myocardium. Its wall consists of smooth muscle cells, elastic fibers and collagen. Thus, it shows an arterial-like structure. However, it differs from the aorta because it is covered by the epicardium and crossed by coronary arteries. These findings indicate that the distal component is morphologically equivalent to the bulbus arteriosus of sharks and chimaeras. In contrast to foregoing descriptions, the valves of the first transverse row are distally anchored to the bulbus arteriosus and not to the ventral aorta. Our findings give added support to the notion that presence of a bulbus arteriosus at the arterial pole of the heart is common to all chondrichtyans, and not an apomorphy of actinopterygians as classically thought.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. CGL2014-52356-P, CEIMAR, BIO 203, FEDE

Registro de tapir centroamericano (Tapirus bairdii) con cámaras-trampa en la sierra Madre de Oaxaca, México

ResumenEn este trabajo se presenta evidencia del tapir centroamericano (Tapirus bairdii) obtenida en la sierra Norte de Oaxaca por medio de cámaras-trampa durante marzo y abril de 2012, confirmando su presencia en esta región.AbstractThis paper presents evidence of the Baird's tapir (Tapirus bairdii) obtained in the Sierra Norte de Oaxaca by camera traps in March and April 2012, confirming its presence in this region

The neutron time-of-flight facility n-TOF at CERN: Phase II

Neutron-induced reactions are studied at the neutron time-of-flight facility n-TOF at CERN. The facility uses 6∼ns wide pulses of 20 GeV/c protons impinging on a lead spallation target. The large neutron energy range and the high instantaneous neutron flux combined with high resolution are among the key characteristics of the facility. After a first phase of data taking during the period 2001-2004, the facility has been refurbished with an upgraded spallation target and cooling system for a second phase of data taking which started in 2009. Since 2010, the experimental area at 185 m where the neutron beam arrives, has been modified into a worksector of type A, allowing the extension of the physics program to include neutron-induced reactions on radioactive isotopes

Mundos virtuales 3D para la comunicación e interacción en el momento educativo online

3D Virtual Worlds offer the possibility of a redesign of communication situations of traditional online education, being its potentiality to restore characteristics of classical classroom education. Here we present the design of a teaching methodology that includes the phases of action for the development of educational activities in 3D platforms as complementary resource for online education. As a result, it is confirmed the positive impact of its use in learning skills, social dimension of learning and student motivation.Los Mundos Virtuales 3D ofrecen la posibilidad de un rediseño de las situaciones de comunicación educativa online tradicionales, siendo su potencialidad la de restituir características propias de la educación presencial clásica. Aquí presentamos el diseño de una metodología docente que recoge las fases de actuación para el desarrollo de actividades educativas en plataformas 3D, como recurso complementario para la enseñanza online. Como resultado, se confirma el impacto positivo de su uso en el aprendizaje de competencias, la dimensión social del aprendizaje y la motivación de los alumnos

Los componentes del tracto de salida cardiaco de los primeros vertebrados mandibulados están conservados en los anfibios

Estudios recientes han modificado las nociones que se habían asumido clásicamente sobre la composición del tracto de salida cardiaco de los condrictios. En este grupo el tracto de salida consta, no sólo de un cono arterioso, de naturaleza miocárdica, sino también de un bulbo arterioso, cuya pared carece de miocardio. El bulbo es un segmento intrapericárdico, interpuesto entre el cono y la aorta ventral, tapizado por epicardio y recorrido por arterias coronarias. Dichos estudios sugieren que este diseño del tracto de salida se corresponde con la condición primitiva del carácter en los vertebrados mandibulados. Además, otra serie de investigaciones han puesto de manifiesto que el bulbo arterioso de los peces es homólogo a las porciones basales intrapericárdicas de la aorta y de la arteria pulmonar de las aves y los mamíferos. Por su parte, aunque la anatomía y fisiología del tracto de salida del corazón de los anfibios constituyen temas frecuentemente tratados en la bibliografía, existe una notable confusión en la terminología empleada para designar esta parte del corazón, motivada, probablemente, por la escasez de estudios microscópicos sobre este componente cardiaco. A tenor de los antecedentes expuestos, se ha estudiado el tracto de salida cardiaco en ejemplares adultos del anuro Xenopus laevis. Dicho estudio ha consistido en el examen anatómico de material fresco, la observación de muestras mediante microscopía electrónica de barrido, la aplicación de técnicas histomorfológicas para microscopía óptica y la realización de reconstrucciones digitales tridimensionales. El tracto de salida cardiaco de X. laevis consta, como el de los vertebrados pisciformes, de dos componentes, uno proximal y otro distal con respecto al ventrículo. El componente proximal es el cono arterioso, que está recorrido internamente por la cresta espiral y presenta, en ambos extremos, sendas hileras de válvulas. La pared del cono es de naturaleza miocárdica y está irrigada por arterias coronarias. El componente distal es asimismo intrapericárdico, está compuesto por musculatura lisa y tejido elástico, está tapizado por epicardio y recorrido por arterias coronarias y muestra una tabicación interna progresivamente más compleja en sentido caudocefálico. Nuestros resultados sugieren que dicho componente distal, que constituye las bases intrapericárdicas de las arterias sistémico-carotídeas y pulmo-cutáneas, es homólogo al bulbo arterioso de los vertebrados pisciformes. Por tanto, el bulbo arterioso se ha conservado desde los primeros vertebrados mandibulados y a partir de él se han formado las bases de los troncos aórticos y pulmonares de los tetrápodos.CGL2014-52356-P (Ministerio de Economía y Competitividad), FPU15/03209 (Ministerio de Educación, Cultura y Deporte), fondos FEDER, Universidad de Málaga.Campus de Excelencia Internacional Andalucía Tech

Aesthetic Quality Properties of Carbonate Breccias Associated with Textural and Compositional Factors: Marrón Emperador Ornamental Stone (Upper Cretaceous, Southeast Spain)

The aesthetic properties of ornamental stones, including colour, texture, and the presence or absence of discontinuities, are influential in their use and marketing. This is particularly critical in brecciated rocks such as the Marrón Emperador (ME) ornamental stone, a dark brown breccia dolostone (Upper Cretaceous, southeast Spain). ME shows a high chromatic and textural variability, which is one of its most appreciated commercial features. Through a petrographic, mineralogical, geochemical and colourimetric study of samples obtained from quarries, outcrops and/or drilling cores, several quality categories have been established, as well as the relationship between the aesthetic properties of ME ornamental stone with its compositional and textural factors. Three main types of breccia constitute the ME exploitable lithotect: crackle and mosaic packbreccias, and rubble floatbreccias. Breccia clasts are mainly composed of hypidiotopic-idiotopic medium- to coarsely-crystalline dolosparites, microcrystalline dolosparites and dolomicrites. Results show that diagenetic processes are mainly responsible for the colour of ME dolostones, revealing that the Sr content is a key factor. The darker brown dolomites always show a higher Sr content, where other typical chromophore elements in dolomites, such as Fe and Mn, do not present this correlation. This study provides evidence for the complexity of processes and factors that are responsible for aesthetic quality features in ornamental stones

El empleo de la cascarilla de algodón en la alimentación de ganado bovino de cebo

Los autores realizan una experiencia de cebo sobre e1nco lotes de bovinos de raza frisona y retinta, con un total de 137 animlles, empleando como alimentos cascarilla de algodón, y cascarilla de algodón más un 30 por 100 de mazorca integral de maiz. Se obtienen incrementos diarios de 1,09 Kg con un consumo energético de 21,7 Mcal/cabeza y día. Los resultados satisfactorios obtenidos, deben atribuirse, fundamentalmente, al alto valor nutritivo de la cascarilla empleada