On the microstructure, growth pattern and original porosity of belemnite rostra: insights from calcitic Jurassic belemnites

Calcitic belemnite rostra are usually employed to perform paleoenvironmental studies based on geochemical data. However, several questions, such as their original porosity and microstructure, remain open, despite they are essential to make accurate interpretations based on geochemical analyses.This paper revisits and enlightens some of these questions. Petrographic data demonstrate that calcite crystals of the rostrum solidum of belemnites grow from spherulites that successively develop along the apical line, resulting in a “regular spherulithic prismatic” microstructure. Radially arranged calcite crystals emerge and diverge from the spherulites: towards the apex, crystals grow until a new spherulite is formed; towards the external walls of the rostrum, the crystals become progressively bigger and prismatic. Adjacent crystals slightly vary in their c-axis orientation, resulting in undulose extinction. Concentric growth layering develops at different scales and is superimposed and traversed by a radial pattern, which results in the micro-fibrous texture that is observed in the calcite crystals in the rostra.Petrographic data demonstrate that single calcite crystals in the rostra have a composite nature, which strongly suggests that the belemnite rostra were originally porous. Single crystals consistently comprise two distinct zones or sectors in optical continuity: 1) the inner zone is fluorescent, has relatively low optical relief under transmitted light (TL) microscopy, a dark-grey color under backscatter electron microscopy (BSEM), a commonly triangular shape, a “patchy” appearance and relatively high Mg and Na contents; 2) the outer sector is non-fluorescent, has relatively high optical relief under TL, a light-grey color under BSEM and low Mg and Na contents. The inner and fluorescent sectors are interpreted to have formed first as a product of biologically controlled mineralization during belemnite skeletal growth and the non-fluorescent outer sectors as overgrowths of the former, filling the intra- and inter-crystalline porosity. This question has important implications for making paleoenvironmental and/or paleoclimatic interpretations based on geochemical analyses of belemnite rostra.Finally, the petrographic features of composite calcite crystals in the rostra also suggest the non-classical crystallization of belemnite rostra, as previously suggested by other authors.

Análisis de la producción científica de los arquitectos técnicos docentes universitarios en España. 1980-2015. Estudio de revistas indizadas en WOS-SCOPUS-CSIC (ICYT-ISOC)

Se estudia la producción científica de los Arquitectos Técnicos docentes universitarios en España en los últimos 35 años ya que el cambio del título académico al de Grado, el aumento del número de doctores y el desarrollo de una política académica que ha convertido en parámetro especial para medir la calidad de la Universidad la cantidad y calidad de los artículos publicados han propiciado un cambio sustancial en esta área del conocimiento. Se determina la investigación producida a través del análisis de las bases de datos WOS-SCOPUS-CSIC(ICYT-ISOC) y las revistas más utilizadas por esta disciplina y se analiza el número de publicaciones de este colectivo por Universidades y revistas. El estudio llevado a cabo evidencia un cambio sustancial en la producción científica de los arquitectos técnicos en España.

Las comedias húngaras de Lope de Vega: una cadena de intertextualidad y reescritura

Dentro del conjunto de comedias dedicadas a la historia de Hungría, Lope de Vega cuenta con tres comedias con numerosas similitudes: El príncipe melanc��lico, El cuerdo loco y La sortija del olvido. Este trabajo examina las relaciones de intertextualidad y reescritura en las tres obras, así como algunos aspectos del desarrollo de la comedia palatina lopesca.

Quintus Curtius before his sources: the episode of Alexander and the Scythians on the Tanais

Quintus Curtius found in his sources a speech where a Scythian censured Alexander, followed by the King’s reply. Curtius drastically abridged this second discourse in order to highlight the criticism of the Macedonian. The Scythian’s words have a striking rhetorical language and some allusions taken from Greek literature, in addition to possible indirect references to Caligula. Curtius declares that he follows his source word-for-word aiming to justify these inconsistencies, but also trying to hide the manipulations he has done to achieve his own narrative purposes.

"Et occidetur virtute Domini Antichristus a Mikaele arcangelo". Paisaje y escatología en Sant Miquel de Llíria (s. XIV d. C.)

El presente articulo intenta determinar las razones por las que el santuario de Sant Miquel de Llíria, uno de los más importantes de la actual provincia de Valencia, se consagró al arc��ngel guerrero. Se estudia para ello la historia de su culto en Occidente, haciendo hincapié en aspectos como su relación con los lugares elevados y la frecuente proximidad de sus santuarios con aquellos dedicados a la Virgen. Atenderemos también a aspectos fundamentales del contexto histórico, como los movimientos de renovación espiritual medievales, la influencia del médico y teólogo Arnau de Vilanova en la Valencia de principios del siglo XIV y las profecías escatológicas vinculadas a la llegada del Anticristo.

Elaboración de un plan de inventarios y sistemas de control de inventarios en la empresa El Carrusel Cía. Ltda

Ingeniero Comercial

Dise?o de un proyecto ambiental a partir de la problem?tica de la Cuenca Media del R?o Ca?averalejo

El presente trabajo plantea c?mo dise?ar una propuesta educativa de manera transversal e interdisciplinar al curr?culo, el cual tiene como objetivo contribuir a la formaci?n ambiental de la comunidad educativa a trav?s de la problem?tica de la cuenca media del r?o Ca?averalejo. Dado que hay muchas Instituciones Educativas que hacen parte de este contexto, esta propuesta est? dirigida a cualquiera de ellas, en el proyecto se aborda como eje transversal la Educaci?n Ambiental, ya que esta juega un papel determinante como medio de cambio cultural, para promover un desarrollo humano integral, implicando para ello una reformulaci?n de actitudes, valores y pr?cticas de los individuos entre s? y de la sociedad en relaci?n a su responsabilidad con el entorno. Para ello fue necesario realizar un diagn?stico de la cuenca media del r?o Ca?averalejo, el cual est? constituido por un conjunto de estudios, an?lisis, propuestas de actuaci?n, seguimiento que abarcan el estado ambiental en todo el ?mbito territorial y el conocimiento de la situaci?n actual de los elementos de un sistema ambiental, en nuestro caso la cuenca del r?o Ca?averalejo, as? como la actividad y comportamiento de dicho sistema. Lo cual sirvi? como fundamento para dise?ar diferentes m?todos y estrategias transversales e interdisciplinares al curr?culo.

Extração de metais (K, Mg, Ba, Ca, Cr, Mn, Li, Fe) de água produzida utilizando sistema microemulsionado

The produced water is a byproduct formed due to production of petroleum and carries with it a high amount of contaminants such as oil particles in suspension, organic compounds and metals. Thus, these latter pollutants are very difficult to treat because of its high solubility in water. The objective of this work is to use and evaluate a microemulsioned system to remove metals ( K , Mg , Ba , Ca , Cr , Mn , Li , Fe ) of synthetic produced water. For the extraction of metals, it was used a pseudoternary diagram containing the following phases: synthetic produced water as the aqueous phase (AP), hexane as organic phase (OP), and a cosurfactant/surfactant ratio equal to four (C/S = 4) as the third phase, where the OCS (saponified coconut oil) was used as surfactant and n-butanol as cosurfactant. The synthetic produced water was prepared in a bench scale and the region of interest in the diagram for the removal of metals was determined by experimental design called. Ten points located in the phase Winsor II were selected in an area with a large amount of water and small amounts of reagents. The samples were analyzed in atomic absorption spectrometer, and the results were evaluated through a statistical assesment, allowing the efficiency analysis of the effects and their interactions. The results showed percentages of extraction above 90% for the metals manganese, iron, chromium, calcium, barium and magnesium, and around 45% for metals lithium and potassium. The optimal point for the simultaneous removal of metals was calculated using statistical artifact multiple response function (MR). This calculation showed that the point of greatest extraction of metals occurs was the J point, with the composition [72% AP, 9% OP, 19% C/S], obtaining a global extraction percentage about 80%. Considering the aspects analyzed, the microemulsioned system has shown itself to be an effective alternative in the extraction of metals on synthetic produced water remediation

Gobierno empresarial: etnografía de un proyecto de cultura organizacional en la C��a. Aceros Ltda

La presente investigación analiza las dinámicas y relaciones sociales de la implementación de un estudio de cultura organizacional en un escenario etnográfico concreto. El propósito del presente trabajo, es analizar el estudio de la cultura organizacional como una técnica de gobierno con unas prácticas específicas, negociadas, consensuadas y establecidas en el marco de la participación de los empleados en el estudio realizado por la empresa.

Avaliação dos teores de N, P, K, Ca, Mg e S em plantas de gravioleira cultivadas em solução nutritiva com omissão de macronutrientes.

Com o objetivo de avaliar os teores de N, P, K, Ca, Mg e S nas folhas, caule e raízes de plantar de gravioleira, conduziu-se experimento em casa de vegetação, utilizando a técnica do elemento faltante. O delineamento experimental foi inteiramente casualizado com quatro repetições e os tratamentos foram: completo, omissão de N, P, K, Ca, Mg e S. Os resultados analíticos evidenciaram que a omissão individual de macronutrientes promoveu alterações nas concentrações de N, P, K, Ca, Mg e S nas plantar de gravioleira. Foram verificados efeitos de varias interações entre os nutrientes. Com base nos teores em g kg-1 dos macronutrientes nas folhas, infere-se, em uma primeira aproximação, dos valores adequados (completo) e do deficiente (omissão), sendo: N =14,70 e 8,82; P = 0,92 e 0,47; K = 12,35 e 2,62; Ca = 14,11 e 3,44; Mg = 3,59 e 1,09; S = 5,32 e 2,30.

Bone response to a Ca- and P-enriched titanium surface obtained by anodization

This study evaluated bone response to a Ca- and P- enriched titanium (Ti) surface treated by a multiphase anodic spark deposition coating (BSP-AK). Two mongrel dogs received bilateral implantation of 3 Ti cylinders (4.1 x 12 mm) in the humerus, being either BSP-AK treated or untreated (machined - control). At 8 weeks postimplantation, bone fragments containing the implants were harvested and processed for histologic and histomorphometric analyses. Bone formation was observed in cortical area and towards the medullary canal associated to approximately 1/3 of implant extension. In most cases, in the medullary area, collagen fiber bundles were detected adjacent and oriented parallel to Ti surfaces. Such connective tissue formation exhibited focal areas of mineralized matrix lined by active osteoblasts. The mean percentages of bone-to-implant contact were 2.3 (0.0-7.2 range) for BSP-AK and 0.4 (0.0-1.3 range) for control. Although the Mann-Whitney test did not detect statistically significant differences between groups, these results indicate a trend of BSP-AK treated surfaces to support contact osteogenesis in an experimental model that produces low bone-to-implant contact values.

Allosteric Control of Gating Mechanisms Revisited: The Large Conductance Ca(2+)-Activated K(+) Channel

Large-conductance Ca(2+)-activated K(+) channels (BK) play a fundamental role in modulating membrane potential in many cell types. The gating of BK channels and its modulation by Ca(2+) and voltage has been the subject of intensive research over almost three decades, yielding several of the most complicated kinetic mechanisms ever proposed. A large number of open and closed states disposed, respectively, in two planes, named tiers, characterize these mechanisms. Transitions between states in the same plane are cooperative and modulated by Ca(2+). Transitions across planes are highly concerted and voltage-dependent. Here we reexamine the validity of the two-tiered hypothesis by restricting attention to the modulation by Ca(2+). Large single channel data sets at five Ca(2+) concentrations were simultaneously analyzed from a Bayesian perspective by using hidden Markov models and Markov-chain Monte Carlo stochastic integration techniques. Our results support a dramatic reduction in model complexity, favoring a simple mechanism derived from the Monod-Wyman-Changeux allosteric model for homotetramers, able to explain the Ca(2+) modulation of the gating process. This model differs from the standard Monod-Wyman-Changeux scheme in that one distinguishes when two Ca(2+) ions are bound to adjacent or diagonal subunits of the tetramer.

Intracellular Ca(2+) Regulation During Neuronal Differentiation of Murine Embryonal Carcinoma and Mesenchymal Stem Cells

Changes in intracellular Ca(2+) concentration ([Ca(2+)](i)) play a central role in neuronal differentiation. However, Ca(2+) signaling in this process remains poorly understood and it is unknown whether embryonic and adult stem cells share the same signaling pathways. To clarify this issue, neuronal differentiation was analyzed in two cell lines: embryonic P19 carcinoma stem cells (CSCs) and adult murine bone-marrow mesenchymal stem cells (MSC). We studied Ca(2+) release from the endoplasmic reticulum via intracellular ryanodine-sensitive (RyR) and IP(3)-sensitive (IP(3)R) receptors. We observed that caffeine, a RyR agonist, induced a [Ca(2+)](i) response that increased throughout neuronal differentiation. We also demonstrated a functional coupling between RyRs and L-but not with N-, P-, or Q-type Ca(v)1 Ca(2+) channels, both in embryonal CSC and adult MSC. We also found that agonists of L-type channels and of RyRs increase neurogenesis and neuronal differentiation, while antagonists of these channels have the opposite effect. Thus, our data demonstrate that in both cell lines RyRs control internal Ca(2+) release following voltage-dependent Ca(2+) entry via L-type Ca(2+) channels. This study shows that both in embryonal CSC and adult MSC [Ca(2+)](i) is controlled by a common pathway, indicating that coupling of L-type Ca(2+) channels and RyRs may be a conserved mechanism necessary for neuronal differentiation.

Exercise training and caloric restriction prevent reduction in cardiac Ca(2+)-handling protein profile in obese rats

Previous studies show that exercise training and caloric restriction improve cardiac function in obesity. However, the molecular mechanisms underlying this effect on cardiac function remain unknown. Thus, we studied the effect of exercise training and/or caloric restriction on cardiac function and Ca(2+) handling protein expression in obese rats. To accomplish this goal, male rats fed with a high-fat and sucrose diet for 25 weeks were randomly assigned into 4 groups: high-fat and sucrose diet, high-fat and sucrose diet and exercise training, caloric restriction, and exercise training and caloric restriction. An additional lean group was studied. The study was conducted for 10 weeks. Cardiac function was evaluated by echocardiography and Ca(2+) handling protein expression by Western blotting. Our results showed that visceral fat mass, circulating leptin, epinephrine, and norepinephrine levels were higher in rats on the high-fat and sucrose diet compared with the lean rats. Cardiac nitrate levels, reduced/oxidized glutathione, left ventricular fractional shortening, and protein expression of phosphorylated Ser(2808)-ryanodine receptor and Thr(17-)phospholamban were lower in rats on the high-fat and sucrose diet compared with lean rats. Exercise training and/or caloric restriction prevented increases in visceral fat mass, circulating leptin, epinephrine, and norepinephrine levels and prevented reduction in cardiac nitrate levels and reduced: oxidized glutathione ratio. Exercise training and/or caloric restriction prevented reduction in left ventricular fractional shortening and in phosphorylation of the Ser(2808)-ryanodine receptor and Thr(17)-phospholamban. These findings show that exercise training and/or caloric restriction prevent cardiac dysfunction in high-fat and sucrose diet rats, which seems to be attributed to decreased circulating neurohormone levels. In addition, this nonpharmacological paradigm prevents a reduction in the Ser(2808)-ryanodine receptor and Thr(17-)phospholamban phosphorylation and redox status. (Hypertension. 2010;56:629-635.)

Dehydromonocrotaline induces cyclosporine A-insensitive mitochondrial permeability transition/cytochrome c release

Monocrotaline (MCT) is a pyrrolizidine alkaloid present in plants of the genus Crotalaria that causes cytotoxicity and genotoxicity in animals and humans. It is well established that the toxicity of MCT results from its hepatic bioactivation to dehydromonocrotaline (DHM), an alkylating agent, but the exact mechanism of action remains unknown. In a previous study, we demonstrated DHM`s inhibition of mitochondrial NADH-dehydrogenase activity at micromolar concentrations, which is an effect associated with a significant reduction in ATP synthesis. As a follow-up study, we have evaluated the ability of DHM to induce mitochondrial permeability transition (MPT) and its associated processes in isolated rat liver mitochondria. In the presence of 10 mu M Ca(2+), DHM (50-250 mu M) elicited MPT in a concentration-dependent, but cyclosporine A-independent manner, as assessed by mitochondrial swelling, which is associated with mitochondrial Ca(2+) efflux and cytochrome c release. DHM (50-250 mu M) did not cause hydrogen peroxide accumulation but did deplete endogenous glutathione and NAD(P)H, while oxidizing protein thiol groups. These results potentially indicate the involvement of mitochondria, via apoptosis, in the well-documented cytotoxicity of monocrotaline. (C) 2009 Elsevier Ltd. All rights reserved.