The stratigraphy of Sierra de Neiba (Dominican Republic)

La reciente cartografía a escala 1:50.000 de los sectores centrales y meridionales, más desconocidos, de la Sierra de Neiba ha permitido establecer con mayor precisión su estratigrafía. Los materiales más antiguos corresponden a la Unidad de El Manguito, del Cretácico Superior. Son calizas y lutitas pizarrosas con intercalaciones de basaltos que afloran como un fragmento o bloque tectónico de interpretación estructural dudosa en el núcleo de un anticlinal. Por su edad, se considera que esta unidad debe constituir el sustrato de las series paleógenas de la Sierra de Neiba; la composición geoquímica de los basaltos (OIB-basaltos alcalinos intraplaca) sugiere su correlación con la meseta oceánica del Caribe. El registro estratigráfico más o menos continuo comienza en el Eoceno Inferior con el desarrollo de una extensa plataforma carbonatada, relativamente uniforme, que fue el medio de depósito de la Fm Neiba (sensu lato) y sus equivalentes, hasta el Mioceno Inferior. Durante buena parte del Eoceno, estos depósitos carbonatados coexistieron o fueron sustituidos por materiales volcánicos de signatura toleítica a alcalina (OIT a OIA) que se agrupan bajo la nueva denominación de Complejo Volcanosedimentario de El Aguacate de Neiba y se interpretan como generados en un contexto de intraplaca asociados al desarrollo de una pluma mantélica. La sedimentación de la Fm Sombrerito durante el Mioceno muestra los primeros signos de inestabilidad en la región: mientras que en los sectores septentrionales y centrales de la sierra sus facies más típicas se depositan en una cuenca turbidítica, en su extremo suroccidental afloran las calizas arrecifales de su Mb Barahona, propias de ambientes de plataforma somera, que se extienden con gran uniformidad hacia el sur hasta los dominios de la Sierra de Bahoruco. La Unidad de Cortadero, de nueva denominación y equivalente en edad a la Fm Sombrerito, con una posición intermedia entre ambos tipos de facies, puede representar el tránsito entre ellas.The recent 1:50.0000 scale mapping of the central and southern, most unknown, parts of the Sierra de Neiba, has allowed to establish its stratigraphy with higher precision. The oldest materials belong to the El Manguito Unit, of Upper Cretaceous age. They are limestones and shales with interbedded basalts that outcrop as part of a fragment or tectonic block of unknown structural origin in the core of an anticline. In view of its age, this unit may be considered to be the substratum of the Sierra de Neiba Palaeogene formations. The geochemical signature of the basalts (OIB-alkaline intraplate basalts) suggests their correlation to the Caribbean oceanic plateau. The continuous stratigraphic record starts in the Lower Eocene with the onset of an extensive relatively uniform carbonate platform that was the depositional environment for the Neiba Fm (sensu lato) and equivalent units up to the Lower Miocene. During most of the Eocene, these carbonate deposits coexisted with, or were replaced by, volcanic materials of a tholeitic to alkaline signature (OIT to OIA) grouped under the new denomination of El Aguacate de Neiba Volcanosedimentary Complex, and interpreted to originate in an intraplate context under the effect of a mantel plume. The sedimentation of the Sombrerito Fm during the Miocene reveals the first signs of regional instability: whereas in the northern and central areas of the sierra its most typical facies were deposited in a turbiditic basin, in its southwest margin the coral reef limestones of the Barahona Mb represent shallow platform environments that extended farther south to the domains of Sierra de Bahoruco. It is suggested that the Cortadero Unit, with the same age as the Sombrerito Fm and an intermediate position between these two extreme kind of facies, may represent the transition from one to the other.Depto. de Mineralogía y PetrologíaFac. de Ciencias GeológicasTRUERepública Dominicana. Dirección General de MineríaUnidad Técnica de Gestión del programa SYSMINpu

Instagraff:The Influence of Web 2.0, Social Media, and User-Created Content Upon Graffiti Culture Performed in Cyber/Space.

Instagraff, graffiti found on the social media website Instagram, examines social and technological advances that have prompted graffiti culture to appear ‘mainstream’. Recognising the birth of Web 2.0 as a key turning point, this study analyses images from social media accounts of graffiti writers, relating them to the works of Goffman (1959), Burgess (2007), and Baudrillard (1970). Its findings suggest that online representations of graffiti culture are no longer necessarily based upon sensory, deviant, risk-taking associated with urban graffiti. The use of social media by young would-be graffiti writers has created new avenues for the commercialisation of a vibrant, but deviant, subculture. Therefore, graffiti shared on social media cannot be considered a true representation of graffiti subculture, but a procession of simulacra, developing new forms of graffiti culture dislocated from graffiti’s deviant origins

Surviving in isolation: genetic variation, bottlenecks and reproductive strategies in the Canarian endemic Limonium macrophyllum (Plumbaginaceae)

Oceanic archipelagos are typically rich in endemic taxa, because they offer ideal conditions for diversification and speciation in isolation. One of the most remarkable evolutionary radiations on the Canary Islands comprises the 16 species included in Limonium subsection Nobiles, all of which are subject to diverse threats, and legally protected. Since many of them are single-island endemics limited to one or a few populations, there exists a risk that a loss of genetic variation might limit their longterm survival. In this study, we used eight newly developed microsatellite markers to characterize the levels of genetic variation and inbreeding in L. macrophyllum, a species endemic to the North-east of Tenerife that belongs to Limonium subsection Nobiles. We detected generally low levels of genetic variation over all populations (HT = 0.363), and substantial differentiation among populations (FST = 0.188;RST = 0.186) coupled with a negligible degree of inbreeding (F = 0.042). Obligate outcrossing may have maintained L. macrophyllum relatively unaffected by inbreeding despite the species’ limited dispersal ability and the genetic bottlenecks likely caused by a prolonged history of grazing. Although several factors still constitute a risk for the conservation of L. macrophyllum, the lack of inbreeding and the recent positive demographic trends observed in the populations of this species are factors that favour its future persistence

La construcción de la mirada en The Ax Fight: la aproximación pedagógica en el cine etnográfico de Tim Asch

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Identification of novel human dipeptidyl peptidase-IV inhibitors of natural origin (part I): virtual screening and activity assays.

BACKGROUND: There has been great interest in determining whether natural products show biological activity toward protein targets of pharmacological relevance. One target of particular interest is DPP-IV whose most important substrates are incretins that, among other beneficial effects, stimulates insulin biosynthesis and secretion. Incretins have very short half-lives because of their rapid degradation by DPP-IV and, therefore, inhibiting this enzyme improves glucose homeostasis. As a result, DPP-IV inhibitors are of considerable interest to the pharmaceutical industry. The main goals of this study were (a) to develop a virtual screening process to identify potential DPP-IV inhibitors of natural origin; (b) to evaluate the reliability of our virtual-screening protocol by experimentally testing the in vitro activity of selected natural-product hits; and (c) to use the most active hit for predicting derivatives with higher binding affinities for the DPP-IV binding site. METHODOLOGY/PRINCIPAL FINDINGS: We predicted that 446 out of the 89,165 molecules present in the natural products subset of the ZINC database would inhibit DPP-IV with good ADMET properties. Notably, when these 446 molecules were merged with 2,342 known DPP-IV inhibitors and the resulting set was classified into 50 clusters according to chemical similarity, there were 12 clusters that contained only natural products for which no DPP-IV inhibitory activity has been previously reported. Nine molecules from 7 of these 12 clusters were then selected for in vitro activity testing and 7 out of the 9 molecules were shown to inhibit DPP-IV (where the remaining two molecules could not be solubilized, preventing the evaluation of their DPP-IV inhibitory activity). Then, the hit with the highest activity was used as a lead compound in the prediction of more potent derivatives. CONCLUSIONS/SIGNIFICANCE: We have demonstrated that our virtual-screening protocol was successful in identifying novel lead compounds for developing more potent DPP-IV inhibitors

Teens, Media and Collaborative Cultures : Exploiting Teens' Transmedia Skills in the Classroom

nonPeerReviewe