Unusual manganese enrichment in the Mesoarchean Mozaan Group, Pongola Supergroup, South Africa

An unusual sediment-hosted manganese deposit is described from the Mesoarchean Mozaan Group, Pongola Supergroup, South Africa. MnO contents up to 15 wt.% were observed in marine clastic and chemical sedimentary rocks. Mn enrichment is interpreted to have resulted from the hydrothermal alteration of manganiferous shale and BIF parent rocks, the primary MnO contents of which are as high as 8.5 wt.%. A detailed mineralogical and petrographic study shows that these parent rocks are characterized by manganoan siderite, ferroan rhodochrosite and other Mn-Fe-rich mineral phases, such as kutnohorite and Fe-Mn-chlorite. Their hypogene alteration gave rise to a diversification of mineral assemblages where ferroan tephroite, calcian rhodochrosite, rhodochrosite, pyrochroite, pyrophanite, cronstedtite, manganoan Fe-rich chlorite and manganoan phlogopite partially or totally replaced the previous mineral assemblage. Thermodynamic modeling performed on chlorite phases associated with the described mineral assemblages illustrates a decrease of average crystallization temperatures from ca. 310 °C during early metamorphic stages to ca. 250 °C during a hydrothermal stage. Mineral transformation processes were thus related to retrograde metamorphism and/or hydrothermal alteration post-dating metamorphism and gave rise to progressive Mn enrichment from unaltered parent to altered rocks. The timing of hypogene alteration was constrained by 40Ar/39Ar dating to between about 1500 and 1100 Ma ago, reflecting tectonic processes associated with the Namaqua-Natal orogeny along the southern Kaapvaal Craton margin. Manganiferous shale and BIF of the Mozaan Group may represent the oldest known examples of primary sedimentary Mn deposition, related to oxidation of dissolved Mn(II) by free oxygen in a shallow marine environment. Oxygenic photosynthesis would have acted as a first-order control during Mn precipitation. This hypothesis opens a new perspective for better constraining secular evolution of sediment-hosted mineral deposits linked to oxygen levels in the atmosphere-hydrosphere system during the Archean Eon

Netlang: A software for the linguistic analysis of corpora by means of complex networks

To date there is no software that directly connects the linguistic analysis of a conversation to a network program. Networks programs are able to extract statistical information from data basis with information about systems of interacting elements. Language has also been conceived and studied as a complex system. However, most proposals do not analyze language according to linguistic theory, but use instead computational systems that should save time at the price of leaving aside many crucial aspects for linguistic theory. Some approaches to network studies on language do apply precise linguistic analyses, made by a linguist. The problem until now has been the lack of interface between the analysis of a sentence and its integration into the network that could be managed by a linguist and that could save the analysis of any language. Previous works have used old software that was not created for these purposes and that often produced problems with some idiosyncrasies of the target language. The desired interface should be able to deal with the syntactic peculiarities of a particular language, the options of linguistic theory preferred by the user and the preservation of morpho-syntactic information (lexical categories and syntactic relations between items). Netlang is the first program able to do that. Recently, a new kind of linguistic analysis has been developed, which is able to extract a complexity pattern from the speaker’s linguistic production which is depicted as a network where words are inside nodes, and these nodes connect each other by means of edges or links (the information inside the edge can be syntactic, semantic, etc.). The Netlang software has become the bridge between rough linguistic data and the network program. Netlang has integrated and improved the functions of programs used in the past, namely the DGA annotator and two scripts (ToXML.pl and Xml2Pairs.py) used for transforming and pruning data. Netlang allows the researcher to make accurate linguistic analysis by means of syntactic dependency relations between words, while tracking record of the nature of such syntactic relationships (subject, object, etc). The Netlang software is presented as a new tool that solve many problems detected in the past. The most important improvement is that Netlang integrates three past applications into one program, and is able to produce a series of file formats that can be read by a network program. Through the Netlang software, the linguistic network analysis based on syntactic analyses, characterized for its low cost and the completely non-invasive procedure aims to evolve into a sufficiently fine grained tool for clinical diagnosis in potential cases of language disorders

Efecto del medio y de la herencia sobre los pesos al nacer, destete y 16 meses de edad en la raza costeño con cuernos

Con el objetivo de estimar parámetros genéticos para los caracteres productivos, pesos al nacer, destete y 16 meses de edad, en la raza Costeño con Cuernos en la estación experimental de Turipaná, ubicada en el municipio de Cereté, norte de Colombia, fueron analizados 1303, 1108 y 841 datos, para los pesos al nacer (PD), al destete (PD) y peso a los 16 meses (P16M), respectivamente, en el periodo 1991 al año 2001. Las medias observadas y desvíos estándares para dichos caracteres fueron 29.03 ± 3.69Kg, 173.27± 23.71Kg y 228.36 ± 27.64Kg., respectivamente. Los valores estimados y los errores para los coeficientes de repetibilidad y de heredabilidad para los PN, PD y P16M fueron 0.05 ± 0.02; 0.08 ± 0.03; 0.082 ± 0.048; 0.26± 0.82 y 0.22 ± 0.089, respectivamente. Los coeficientes de correlación genética fueron 0.19 para PN x PD y 0.045 para PD x P16M

Remarks on Non-Abelian Duality

A class of two-dimensional globally scale-invariant, but not conformally invariant, theories is obtained. These systems are identified in the process of discussing global and local scaling properties of models related by duality transformations, based on non-semisimple isometry groups. The construction of the dual partner of a given model is followed through; non-local as well as local versions of the former are discussed.Comment: 33 pages, CERN-TH.7414/94, RI-9-94, WIS-7-9

El problema es el “ladrillo” de la materia de “metodología de la investigacion”

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El problema es el “ladrillo” de la materia de “metodología de la investigacion”

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Hacia una teoría de la mente corporizada: la influencia de los mecanismos sensomotores en el desarrollo de la cognición

The aim of this article is to contribute to spread the enactive principles to design a theory of mind - and extensively, to provide new foundations for Artificial Intelligence. This theory has lately been progressively modifying the conviction that the mind is, above all, centered on the management of concepts. The abstract mind and its symbolic support have been the pillars of the cognitive paradigm, base of the traditional Artificial Intelligence. However, results obtained from the 1990's about the embodiment and situational cognition, completed in the last years with the updating carried out by authors as the neurophysiologist Francisco Varela, have permitted to define an alternative theoretical construct towards computationalism. We attempt to show a historical tour up to date and the problems that cognitive sciences have encountered in this trip to lay the foundations of some new pillars for a theory that allows understanding the mind.El objeto de este artículo es ayudar a divulgar los principios enactivistas para el diseño de una teoría de la mente (y por extensión, para dotar de nuevos fundamentos a la Inteligencia Artificial) que en los últimos años están desmontando progresivamente la convicción de que la mente se centra, ante todo, en manejar conceptos. El pensamiento abstracto y su soporte simbólico han sido los pilares del paradigma cognitivista, base de la inteligencia artificial tradicional. Sin embargo, los resultados provenientes de finales de la década de los 90 del siglo pasado sobre corporización y situacionalidad de la cognición, complementados por la puesta al día en los últimos años del trabajo de autores como el neurofisiólogo Francisco Varela, están permitiendo definir un constructo teórico alternativo al computacionalismo. Pretendemos mostrar elrecorrido histórico hasta la actualidad y los problemas que las ciencias cognitivas se han ido encontrando en este viaje de fundamentación de unos nuevos pilares para una teoría que permita la comprensión de la mente

First record of promops davisoni (Thomas, 1921) (chiroptera, molossidae) from Chile and a description of its echolocation calls

[Primer registro de promops davisoni (Thomas, 1921) (chiroptera, molossidae) en Chile, y des-cripción de sus llamadas de ecolocación]Few studies have been conducted on the bat fauna of the Arica and Parinacota region, northern Chile. The genus Promops (Gervais, 1855) is a poorly known group of molossid bats, with three species widely distributed in Central and South America. We report for the first time the species Promops davisoni in Chile. Identification was based on echolocation calls obtained at the Azapa and Lluta valleys and compared to reference calls from Tacna, Peru. We report the species as far as 127 km south of the previous published southernmost record in Pampa Alta, Peru. In addition we obtained an individual found at the Anzota caves, near the city of Arica. The species is found on the coast and in the fluvial valleys of Northern Chile, with altitudes ranging from sea level to 822 m a.s.l. We propose that the distribution of P. davisoni may extend further south, to the locality of Tana in the Tarapacá region, based on the capacity of the species to cross distances of over 100 km over large desert areas. With this species, we increase the known bat fauna of Chile to 14 species, and the bat fauna of the Arica and Parinacota region to nine species. © SAREM, 2018.Peer reviewe

A Problem with Non-Abelian Duality

We investigate duality transformations in a class of backgrounds with non-Abelian isometries, i.e. Bianchi-type (homogeneous) cosmologies in arbitrary dimensions. Simple duality transformations for the metric and the antisymmetric tensor field, generalizing those known from the Abelian isometry (Bianchi I) case, are obtained using either a Lagrangian or a Hamiltonian approach. Applying these prescriptions to a specific conformally invariant \s-model, we show that no dilaton transformation leads to a new conformal background. Some possible ways out of the problem are suggested.Comment: 14pages, CERN-TH.6960/93 ROM2F/93/24 (One reference and one paragraph added

Bio-based electrospun fibers for wound healing

Being designated to protect other tissues, skin is the first and largest human body organ to be injured and for this reason, it is accredited with a high capacity for self-repairing. However, in the case of profound lesions or large surface loss, the natural wound healing process may be ineffective or insufficient, leading to detrimental and painful conditions that require repair adjuvants and tissue substitutes. In addition to the conventional wound care options, biodegradable polymers, both synthetic and biologic origin, are gaining increased importance for their high biocompatibility, biodegradation, and bioactive properties, such as antimicrobial, immunomodulatory, cell proliferative, and angiogenic. To create a microenvironment suitable for the healing process, a key property is the ability of a polymer to be spun into submicrometric fibers (e.g., via electrospinning), since they mimic the fibrous extracellular matrix and can support neo- tissue growth. A number of biodegradable polymers used in the biomedical sector comply with the definition of bio-based polymers (known also as biopolymers), which are recently being used in other industrial sectors for reducing the material and energy impact on the environment, as they are derived from renewable biological resources. In this review, after a description of the fundamental concepts of wound healing, with emphasis on advanced wound dressings, the recent developments of bio-based natural and synthetic electrospun structures for efficient wound healing applications are highlighted and discussed. This review aims to improve awareness on the use of bio-based polymers in medical devices