Técnicas para la preparación de esqueletos secos de lepidosaurios

Se describen en detalle dos técnicas para la preparación de esqueletos secos de lepidosaurios, 1.- La técnica de maceración bacteriana en agua genera la total desarticulación del ejemplar preparado mediante la descomposición de los tejidos blandos, sin producir ninguna alteración química o física de los elementos óseos, permitiendo observar la naturaleza del contacto entre distintos elementos óseos; 2.- La técnica mediante hipoclorito de sodio (NaClO) que propicia la disolución de los tejidos blandos, permitiendo preservar al ejemplar en el estado de articulación deseado. Sin embargo, esta técnica puede producir cierto grado de descalcificación, dependiendo de las concentraciones utilizadas de NaClO y del tiempo de exposición a la misma. Ambas técnicas han sido utilizadas con éxito en otros vertebrados como anuros y pequeños mamíferos.Two techniques for the preparation of dry skeletons of small-sized lepidosaurs are described here, 1.- The technique of bacterial maceration in water generates total disarticulation of the specimens through anaerobic decomposition of soft tissues, without any chemical or physical modifi cation of bones. This technique has demonstrated to be useful for the observation of articular surfaces or of contact between bony elements; 2.- The diluted solutions of sodium hypochlorite (NaClO) technique is useful to quickly dissolution of soft tissues, allowing the preservation of bony elements in articulation. However, it presents the inconvenience of a slight decalcifi cation of the specimens. These techniques have been also used with positive results in anurans and small-sized mammals.Fil: Scanferla, Carlos Agustín. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales; Argentin

Postnatal ontogeny and the evolution of macrostomy in snakes

Macrostomy is the anatomical feature present in macrostomatan snakes that permits the ingestion of entire prey with high cross-sectional area. It depends on several anatomical traits in the skeleton and soft tissues, of which the elongation of gnathic complex and backward rotation of the quadrate represent crucial skeletal requirements. Here, the relevance of postnatal development of these skull structures and their relationship with macrohabitat and diet are explored. Contrary to the condition present in lizards and basal snakes that occupy underground macrohabitats, elements of the gnathic complex of most macrostomatan snakes that exploit surface macrohabitats display conspicuous elongation during postnatal growth, relative to the rest of the skull, as well as further backward rotation of the quadrate bone. Remarkably, several clades of small cryptozoic macrostomatans reverse these postnatal transformations and return to a diet based on prey with low cross-sectional area such as annelids, insects or elongated vertebrates, thus resembling the condition present in underground basal snakes. Dietary ontogenetic shift observed in most macrostomatan snakes is directly linked with this ontogenetic trajectory, indicating that this shift is acquired progressively as the gnathic complex elongates and the quadrate rotates backward during postnatal ontogeny. The numerous independent events of reversion in the gnathic complex and prey type choice observed in underground macrostomatans and the presence of skeletal requirements for macrostomy in extinct non-macrostomatan species reinforce the possibility that basal snakes represent underground survivors of clades that had the skeletal requirements for macrostomy. Taken together, the data presented here suggest that macrostomy has been shaped during multiple episodes of occupation of underground and surface macrohabitats throughout the evolution of snakes.Fil: Scanferla, Carlos Agustín. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Bio y Geociencias del NOA. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Museo de Ciencias Naturales. Instituto de Bio y Geociencias del NOA; Argentin

Studies on 6-sector-site deployment in downlink LTE

Mobile data traffic is expected to increase massively in the following years. Consequently, service operators are induced to increase the capacity of their networks continually to attract more subscribers and maximize their revenues. At the same time, they want to minimize operational costs and capital expenditures. Among the alternatives that aim to increase the network capacity, higher order sectorization, and in particular a six sectorized configuration, is nowadays attracting a lot of attention for LTE macro-cell deployments since a higher number of sectors per site results in improved site capacity and coverage. A six sectorized configuration is attractive for both roll-out phase and growth phase of the network. In the roll-out phase, the radio access network is planned with 6-sector sites instead of 3-sector sites with the advantage that less sites are needed for the same capacity and coverage requirements. In the growth phase, the six sectorized configuration can be used to upgrade existing 3-sector sites where the traffic grows beyond the current sites' capabilities. Therefore, no additional expensive and time consuming contracts need to be signed for the locations of the new sites, while the existing sites are used more efficiently. However, although potentially a 6-sector site can offer a double capacity than a 3-sector site, several factors prevent the capacity from growing proportionately to the number of sectors. Consequently, there is an uncertainty on whether the capacity gain is high enough to justify the extra costs of the additional equipment and, more specifically, whether the 6-sector-site deployment is more economically attractive than a 3-sector-site deployment. The aim of this report is to solve this uncertainty. First, we present the main factors that affect the capacity gain. Next, we quantify the impact of these factors on the capacity gain in downlink LTE with the use of a system level simulator. Finally, we use the results of the simulation study as inputs for an economic study to access the reasons for a possible deployment of 6-sector sites instead of 3-sector sites for LTE

Energy Efficient Glazed Office Building Envelope Solutions for Different European Climates

The aim of this study is to show the critical aspects of a completely glazed high rise office building from an energy efficiency point of view in different European climates. The achievable consumptions and the most influential parameters such as glazing U-value, VT/SHGC and shading and their optimal values were investigated. The study has been carried out for a theoretical office building in Italy and Lithuania, representatively of a southern and northern EU climate. The building chosen is representative of all the glazed-simple shape buildings and the analysis of the entirety of the building enables a clear and im-mediate outcome of global consumptions. Number of DesignBuilder simulations were performed and the annual consumptions are summed with the primary energy criteria. Results show the critical aspects of 100% WWR buildings: in the coldest climate the main problem is the huge surface of relatively high glass U-value compared with standard walls, while in the warmer one the main efforts need to be done to avoid the summer overheating caused by incoming solar radiation. Finally, it is shown that it is difficult to lower the overall primary energy consumptions below 130 and 140 kWh/m2a for North-Italy and Lithuania locations respectively. The analysis is focused only in the envelope parameter, thus it is not included renewable energy systems, which can generate higher energy efficiencies

Exquisitely preserved fossil snakes of messel: Insight into the evolution, biogeography, habitat preferences and sensory ecology of early boas

Our knowledge of early evolution of snakes is improving, but all that we can infer about the evolution of modern clades of snakes such as boas (Booidea) is still based on isolated bones. Here, we resolve the phylogenetic relationships of Eoconstrictor fischeri comb. nov. and other booids from the early-middle Eocene of Messel (Germany), the best-known fossil snake assemblage yet discovered. Our combined analyses demonstrate an affinity of Eoconstrictor with Neotropical boas, thus entailing a South America-to-Europe dispersal event. Other booid species from Messel are related to different New World clades, reinforcing the cosmopolitan nature of the Messel booid fauna. Our analyses indicate that Eoconstrictor was a terrestrial, medium- to large-bodied snake that bore labial pit organs in the upper jaw, the earliest evidence that the visual system in snakes incorporated the infrared spectrum. Evaluation of the known palaeobiology of Eoconstrictor provides no evidence that pit organs played a role in the predator–prey relations of this stem boid. At the same time, the morphological diversity of Messel booids reflects the occupation of several terrestrial macrohabitats, and even in the earliest booid community the relation between pit organs and body size is similar to that seen in booids todayFil: Scanferla, Carlos Agustín. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Bio y Geociencias del NOA. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Museo de Ciencias Naturales. Instituto de Bio y Geociencias del NOA; Argentina. Senckenberg Research Institute; AlemaniaFil: Smith, Krister T.. Senckenberg Research Institute; Alemania. Goethe Universitat Frankfurt; Alemani

3D printed geopolymeric lattices: Effect of different filler materials on mechanical properties

Our group developed mixtures based on geopolymer for additive manufacturing of porous components via direct ink writing (DIW). We optimized the rheological properties in order to obtain suitable inks for the production of highly porous lattices. It should be noted that, as geopolymer mixtures are subjected to ongoing poly-condensation reactions, their viscosity changes with time in what can be seen as a 4D printing process. Different materials were added to the mixture, such as glass and plastic fibers, as well as fillers like sand, to produce innovative 3D printed geopolymeric composites. The influence of these materials on the mechanical properties was evaluated

How to minimize the environmental contamination caused by hydrocarbon releases by onshore pipelines: The key role of a three-dimensional three-phase fluid flow numerical model

The contamination impact and the migration of the contaminant into the surrounding environment due to the presence of a spilled oil pipeline will cause significant damage to the natural ecosystem. For this reason, it is decisive to develop a rapid response strategy that might include accurate predictions of oil migration trajectories from numerical simulation modeling. In this paper, a three-dimensional model based on a high-resolution shock-capturing conservative method to resolve the nonlinear governing partial differential equations of the migration of a spilled light nonaqueous liquid oil contaminant in a variably saturated zone is employed to investigate the migration of the oil pipeline leakage with great accuracy. The effects on the oil type density, gasoline and diesel oil, the unsaturated zone depth, its saturation, the hydraulic gradient, and the pressure oil pipeline are investigated through the temporal evolution of the contaminant migration following the saturation profiles of the three-phase fluids flow in the variably saturated zone. The calculation results indicate that the leaking oil's pressure is the parameter that significantly affects the contaminants' arrival time to the groundwater table. Also, the water saturation of the unsaturated zone influences the arrival time as the water saturation increases for a fixed depth. The unsaturated zone depth significantly influences the contaminant migration unsaturated zone. At the same time, the oil density and the hydraulic gradient have limited effects on the contaminant migration in the variably saturated zone.Comment: 46 pages, 19 figure

Duplex 2404: caratterizzazione microstrutturale dopo trattamenti termici

Caratterizzazione microstrutturare dell'acciaio inossidabile lean duplex LDX 2404 come materiale tal quale, solubilizzato e trattato isotermicamente a temperature interne all'intervallo critico. Si cercata la temperatura ottimale di solubilizzazione ed indagato se l'acciaio presenti precipitazione di fasi secondarie dopo trattaemnti isotermiciope

Eficacia de células madre en rehabilitación ósea en pacientes con atrofia ósea alveolar: revisión sistemática

En condiciones estables, a nivel óseo, existe un equilibrio constante entre reabsorción y formación ósea. En pacientes sujetos a traumas, enfermedad periodontal, resecciones quirúrgicas por tumores o malformaciones congénitas, esta armonía falla. Para garantizar funciones diarias, como masticación o fonación resulta necesario regenerar hueso alveolar para favorecer la colocación, en segundo lugar, de implantes dentales que sustituyan los dientes ausentes. El presente estudio pretende estudiar como la ingeniera biomédica, mediante el uso de células madre sea capaz de rehabilitar pacientes con atrofias óseas alveolares y pueda representar el futuro de la regeneración ósea en odontología.Universidad Europea de ValenciaGrado en OdontologíaPresencia

El origen y evolución temprana de las serpientes : Análisis anatómico y filogenético de los ofidios cretácicos y paleógenos de la Patagonia y Bolivia

Este trabajo de tesis doctoral tiene como objetivo principal el análisis de dos relevantes escamados procedentes del Cretácico Superior de la Patagonia Argentina, Najash rionegrina y Dinilysia patagonica, como así también dos nuevas serpientes avanzadas del grupo de los Macrostomata, (denominados Taxón A y B) procedentes de la localidad del Terciario Inferior (Paleoceno) de Tiupampa, Bolivia. Se realizó un análisis anatómico detallado de estos taxones fósiles en conjunto con un gran número de representantes de los más relevantes grupos de serpientes actuales, complementando estas observaciones con imágenes obtenidas a través de tomografía computada de rayos X y microscopía electrónica. Para evaluar las relaciones filogenéticas de los taxones motivo de esta tesis se realizó un análisis cladístico en el cual se combinaron datos morfológicos y moleculares, el cual arrojó novedosos resultados como así también la confirmación de algunos grupos previamente propuestos. Najash rionegrina y Dinilysia patagonica constituyen sucesivos grupos hermanos de todas las demás serpientes fósiles y vivientes, de esta manera quedando ambos taxones excluidos del clado Serpentes. A su vez, el grupo de escamados más cercanamente emparentado a este grupo son los saurios ápodos fosoriales Amphisbaenia-Dibamidae. Las serpientes marinas cretácicas de Medio Oriente (Pachyrhachis, Haasiophis y Eupodophis), como así también los "Madtsoideos" australianos (Wonambi y Yurunggur) se emplazan claramente dentro de Serpentes, constituyendo grupos bien definidos dentro de Macrostomata, aunque con afinidades inciertas con los demás clados de este gran grupo de serpientes avanzadas. Estos rasgos topológicos obtenidos indican que el origen de las serpientes aconteció en ambientes terrestres, sugiriendo a su vez que la alternancia de hábitos de vida fosorial-de superficie presentes en los taxones que conforman el linaje de escamados que dio origen al grupo modeló el plan corporal que hoy en día poseen las serpientes. El Taxón A constituye el grupo hermano de los Tropidophiidae (Tropidophis y Trachyboa), serpientes Macrostomata actuales distribuidas en Centro y Sudamérica,constituyendo así el primer taxón fósil relacionado a este grupo de serpientes Neotropicales. Así, es posible inferir que la historia de estas serpientes posee una edad mínima de 60 millones de años en el continente Americano, siendo congruente con la hipótesis que plantea un origen de los Tropidophiidae en este continente. El Taxón B emerge como el grupo hermano de Caenophidia, grupo que incluye a las serpientes más derivadas, constituyendo la primer evidencia en lo que respecta a los orígenes del grupo de serpientes más diverso en la actualidad. La morfología del maxilar y su dentición de tipo anisodonte con una notoria diastema permite inferir que dicha especie poseyó un sistema de inoculación de veneno, el cual representa el registro más antiguo de dicho complejo morfofuncional. Así, la presencia de sistemas de inoculación de veneno parece no ser un atributo propio de los Caenophidia más derivados como fuera planteado previamente, indicando que el/los sistemas de inoculación de veneno en serpientes estuvieron más ampliamente distribuidos dentro de los Macrostomata de lo que se pensó previamente. Así, gracias a su creciente registro fósil, América del Sur emerge como una de las regiones del planeta con mayor relevancia en cuanto al origen y evolución de las serpientes.Facultad de Ciencias Naturales y Muse