Linguloidean brachiopods from the Lower Ordovician (Tremadocian) of northwestern Argentina

The new obolid Torobolus subplanus gen. et sp. nov., from the lower Temadocian Devendeus Formation, the new species Libecoviella tilcarensis and Leptembolon argentinum, and Ectenoglossa sp. from upper Tremadocian beds of the Santa Rosita Formation are described and ilustrated. Libecoviella is typical of the upper Tremadocian and Floian strata of the Prague basin (Trenice and Klabava formations, respectively) and it has been reported recently from Australia. Leptembolon has been recorded in the same Bohemian formations, but together with other taxa it forms the Thysanotos-Leptembolon Association present in northern Estonia and a series of high-latitude terranes. The record of Leptembolon and Libecoviella in the high- to temperate-latitude Central Andean region attests for a peri-Gondwanan distribution of these genera. The presence of Bohemian-like obolids in northwestern Argentina suggests a migratory route linking the Central Andean basin with north Gondwana and Perunica along the clastic platforms fringing the North African and Brazilian shieldsFil: Benedetto, Juan Luis Arnaldo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones en Ciencias de la Tierra. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Investigaciones en Ciencias de la Tierra; ArgentinaFil: Muñoz, Diego Fernando. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones en Ciencias de la Tierra. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Investigaciones en Ciencias de la Tierra; Argentin

The eoorthid brachiopod Apheoorthina in the Lower Ordovician of NW Argentina and the dispersal pathways along western Gondwana

The eoorthid brachiopod Apheoorthina is reported for the first time from the Lower Ordovician of NW Argentina. It is represented by a species similar to A. ferrigena from the Tremadocian of the Prague Basin, increasing the faunal affinities between the Central Andean Basin and the South European microcontinents, in particular the Bohemian region (Perunica). Nine out of the fourteen brachiopod genera reported from the Tremadocian of the Central Andean Basin (~64 %) are shared with the Mediterranean region, four of which (~ 28 %) have been recorded in the Prague Basin, and two (Kvania and Apheoorthina) are restricted to the Central Andes and Perunica. Dispersal pathways around Gondwana are analyzed in the light of major factors affecting large-scale distribution of brachiopods (environment, larval capacity for dispersal, oceanic currents).The presence in Apheoorthina aff. ferrigena of a well-preserved larval protegulum measuring 420 μm in width and 210 μm in length strongly suggests that this species had planktotrophic larvae capable of long-distance dispersal. According to recent oceanatmosphere general circulation models for the Ordovician Period, the Central Andean margin was dominated by the cold-water Antarctica Current. Despite the complex nonzonal pattern produced by current deflections around the peri-Gondwanan microcontinents, the general westward circulation sense favoured larval dispersal from the Andean region to North Africa, Avalonia, the Armorican Terrane Assemblage, and Perunica. On the other hand, the eastwards flowing Gondwana Current connected the North Gondwana waters with the South American epicontinental seas, which could explain the reversed migration of some brachiopods.Fil: Muñoz, Diego Fernando. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones en Ciencias de la Tierra. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Investigaciones en Ciencias de la Tierra; ArgentinaFil: Benedetto, Juan Luis Arnaldo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones en Ciencias de la Tierra. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Investigaciones en Ciencias de la Tierra; Argentin

Distance-based kernels for real-valued data

We consider distance-based similarity measures for real-valued vectors of interest in kernel-based machine learning algorithms. In particular, a truncated Euclidean similarity measure and a self-normalized similarity measure related to the Canberra distance. It is proved that they are positive semi-definite (p.s.d.), thus facilitating their use in kernel-based methods, like the Support Vector Machine, a very popular machine learning tool. These kernels may be better suited than standard kernels (like the RBF) in certain situations, that are described in the paper. Some rather general results concerning positivity properties are presented in detail as well as some interesting ways of proving the p.s.d. property.Peer ReviewedPostprint (author's final draft

Butyrate oxidation by liver enzymes

originalFil: Leloir, Luis Federico. Instituto de Fisiología. Facultad de Medicina. Universidad de Buenos Aires; ArgentinaFil: Muñoz, Juan M.. Instituto de Fisiología. Facultad de Medicina. Universidad de Buenos Aires; ArgentinaBlanco y negro8 páginas en pdfLFL-PI-O-ART. Artículos científicosUnidad documental simpleAR-HYL-201

Modelling and frequency analysis of semi-active controlled suspension systems of an automobile

This paper presents the modeling, analysis and performance comparison of passive, semi-active and active controlled suspension systems of an automobile. Starting from a simplified quarter car suspension model, a frequency analysis in a proposed passive suspension is made, evaluating its performance against the variation of some of its parameters. Subsequently, a comparison between the passive and actuated (semi-active) suspension systems is presented, so as to show their advantages and disadvantages. Finally, several types of semi-active suspension controllers are proposed (modified Skyhook, modified Groundhook, PID, Model predictive control) and compared to each other

Fatty acid oxidation by liver enzymes

originalFil: Muñoz, Juan M.. Instituto de Fisiología. Facultad de Medicina. Universidad de Buenos Aires; ArgentinaFil: Leloir, Luis Federico. Instituto de Fisiología. Facultad de Medicina. Universidad de Buenos Aires; ArgentinaBlanco y negro8 páginas en pdfLFL-PI-O-ART. Artículos científicosUnidad documental simpleAR-HYL-201

Naturaleza, jardín y ciudad en el Nuevo Mundo

El artículo se basa en el capítulo 5 (punto 5.2) de la tesis doctoral. Explica la relación entre la forma urbana y la naturaleza del entorno, así como la introducción de la naturaleza (alamedas y paseos) en la estructura urbana de la ciudad colonia

Beach Nourishment: A 21st Century Review

Long-term erosion is experienced by most of the coastlines worldwide, and it is usually attributed not only to sea level rise but also to the retention of sand in dams, the occupation of dry beaches by urbanized areas, the disturbance of the natural patterns of longshore drift, the mining of sand as building material for construction, and so on. Beach nourishment has evolved as the favored erosion-mitigation strategy in many areas of the world. The increasing number of people living on the coast, the safety of those people, and the high values of coastal property are all factors that have made beach nourishment a cost-effective strategy for managing erosion in many locations. However, a new scenario of sand scarcity and environmental care has arisen in recent decades. There have been a number of different and interesting cases of various aspects of beach nourishment in the last years. The purpose of this Special Issue has been to publish the different experiences and research related to this topic. After a careful review process, nine papers were included. Their thematic contributions include the use of field methods such as the use of remotely piloted aircraft systems (RPAS) or un-manned aerial vehicles (UAV) for faster and automated mapping of the coastal area or the acquisition of geomagnetic data in marine environments; the use of multi-approach methodologies to assess the interaction between coastal structures and beaches and in particular of submerged pipelines; the need to adopt a plan for the optimal use of limited resources of available sediment from a regional perspective and the assessment of the effectiveness of beach nourishments; the understanding of the role of submerged geological control of beach profiles together with the implementation of innovative beach nourishment strategies while facing the non-trivial challenge of visualizing and communicating mesoscale modeling assumptions, uncertainties and outcomes to both coastal specialists and decision makers; and the influence of sea-level rise and erosion on diminution of beach habitats

A new approach to influence analysis in linear models

propose a new approach to the study of influence in the General Linear Model based on conditional bias. This approach enables us to apply such an analysis to all particular cases of this model. The theoretical foundation, on which this approach is based, does not presuppose a particular hypothesis on the distribution of the variables. Applying the results obtained to the Multiple Linear Regression Model, measures of influence are obtained as already proposed by other authors. Finally we carry out an application of the results on the analysis of covariance

Non-Lipschitz differentiable functions on slit domains

It is proved the existence of large algebraic structures –including large vector subspaces or infinitely generated free algebras– inside the family of non-Lipschitz differentiable real functions with bounded gradient defined on special non-convex plane domains. In particular, this yields that there are many differentiable functions on plane domains that do not satisfy the Mean Value Theorem.Plan Andaluz de Investigación (Junta de Andalucía)Ministerio de Economía y Competitividad (MINECO). Españ