51 research outputs found

    NUEVOS APORTES AL CONOCIMIENTO DE LA HERPETOFAUNA DE LA FORMACIÓN CERRO AZUL (MIOCENO SUPERIOR), PROVINCIA DE LA PAMPA, ARGENTINA

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    ABSTRACTNew fossil specimens of amphibians and reptiles found in several localities of the Cerro Azul Formation (Upper Miocene) from La Pampa province are described. The new records include a fragmentary skull remain assigned to the frog genusCeratophrys, carapace fragments of the tortoise genusChelonoidis, vertebrae referred to the lizardTupinambis, and a trunk vertebra of a colubroid snake compared with the living colubroid genusPhilodryas. Previous Tertiary records of genera of amphibians and reptiles, as well as the studied assemblage from the Upper Miocene of La Pampa, indicate that almost the modern genera that conform the Neotropical herpetofauna were well in progress by the Miocene, a similar pattern observed in other parts of the world.RESUMENSe describen nuevos materiales fósiles de anfibios y reptiles hallados en sedimentos referidos a la Formación Cerro Azul (Mioceno Superior), procedentes de numerosas localidades de la provincia de La Pampa, Argentina. Los nuevos registros se basan en un resto craneano de anuro asignado al géneroCeratophrys, restos de caparazón de tortugas terrestres del géneroChelonoidis, vértebras asignables al lagarto de la familia TeiidaeTupinambis, y una vértebra troncal de serpiente comparable al género de colubroideos actualesPhilodryas. Tanto los registros terciarios previos de géneros actuales de anfibios y reptiles en América del Sur, como así también la asociación recuperada en el Mioceno Superior de La Pampa sugieren que la mayoría de los géneros que componen la herpetofauna Neotropical estaban presentes en el Mioceno, patrón similar al observado en otras regiones del mundo

    Identification of most relevant variables and processes to assess the environmental impacts of remediation technologies along their life cycles: Focus on the waste management scenarios

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    The application of Life Cycle Assessment (LCA) to remediation technologies is still not a consolidated practice and it is especially lacking in the assessment of the environmental impacts associated to the management of the waste produced during remediation. This study aims at addressing these methodological gaps by identifying the typologies of waste typically generated during the remediation of a contaminated site and classifying them according to the European Waste Catalogue (EWC) codes. Thereafter, the following steps are: (i) the identification of the waste management scenarios (WMSs) applicable to the identified waste typologies, (ii) the selection of Life Cycle Assessment processes that can be used to assess the impacts of the different WMSs and (iii) the quantification and comparison of the environmental impacts caused by the different WMSs applied considering hazardousness levels to which the same waste may belong in relation to its contamination levels and characteristics: inert, non-hazardous and hazardous waste (Waste Framework Directive 2008/98/EC). As results, a matrix reporting the classes and typologies of waste, their EWC codes, their different WMSs and the suitable LCA processes from the Ecoinvent database that can be applied to each EWC within a specific WMS, has been developed. Additionally, the comparative assessment of the impacts caused by the Ecoinvent processes applicable to the same waste typology within the same WMS has been performed to support the selection of the most appropriate WMS case by case

    A methodology to assess a mobile urban street cleaning activity

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    An experimental methodology to assess the human exposure of a street cleaning service, performed by a worker handling a leaf blower followed by a water-flushing sweeper, was developed. The sampling campaign was achieved by considering data from road dust, personal air sampling and portable particulate matter detector. The experimental design allowed to obtain qualitative and quantitative information on the chemical composition of road dust, the size and chemical composition of potentially inhalable particles suspended during the street cleaning activity, as well as the duration of the particles' suspension effect. The methodology employed showed: i) the compliance with the occupational exposure threshold values for the total inhalable dust and with the occupational exposure limit values according to national and international regulatory approaches for polycyclic aromatic hydrocarbons (PAH) and inorganic elements; ii) a good agreement of the metals concentrations from the road dust (i.e., calcium, magnesium, potassium, iron, aluminium and sodium) with those from the material collected by the personal air sampler, highlighting the negligible effect of the investigated sweeping activity compared to the material already present on the road; iii) a similar pattern of inorganic elements within the three different monitoring areas; iv) a “dust wave” effect detected by the particle counter lasting no more than 2 min. Thus, such information suggested that performing the urban sweeping activity in the early mornings, when there is a general low PM10-PM2.5 average concentration, low traffic intensity, and the almost absence of passers-by, lead to a low probability of citizens’ exposure

    Reproducibility of Buccal Gingival Profile Using a Custom Pick-Up Impression Technique : A 2-Year Prospective Multicenter Study

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    Purpose The aim of this study was to transfer the provisional restoration emergence profile to the final implant-supported restoration and to buccal gingival margin (BGM) stability after 2 years of function. Materials and Methods A total of 33 patients were recruited for treatment of single gaps by means of 33 implant-supported restorations. Fixed provisional crowns were screwed to the fixture and adjusted until the complete peri-implant soft tissue maturation was achieved. After 12 weeks, a second fixture impression was taken by means of a pick-up customization technique in order to transfer the clinical aspect of the peri-implant soft tissues to the master cast. A definitive restoration was delivered. A standardized method from digital photographs was used to assess the gingival margin modification (BGM) from the provisional (P) to the definitive prosthesis installation at baseline (D0), and after 1 (D1) and 2 years (D2) of function. Also, marginal bone loss (MBL) was calculated after 1 (D1) and 2 years (D2) of definitive restoration function. Results The BGM index at the time of the final restoration installation (D0) was 0.12 \ub1 0.33 mm if compared with the BGM position of the provisional restoration (P); it was of 0.12 \ub1 0.46 mm after 1-year of follow-up (D1) and of 0.31 \ub1 0.21 after 2 years of function (D2). No significant difference was calculated between measurements in different follow-up visits (p > 0.05). No significant MBL was measured between the baseline (D0) and the 1-year follow-up (p = 0.816) with a mean MBL value of 0.2 \ub1 0.1 mm. Similar result was calculated after 2 years (p = 0.684) with a mean MBL value of 0.3 \ub1 0.2. Conclusion A modified impression pick-up may be helpful to reproduce the gingival margin position from the provisional to the definitive restoration. Moreover, the gingival zenith position during the follow-up period seemed to be stable. Clinical Significance The modification of the standard impression pick-up technique may contribute to reproducing a natural emergence profile of esthetic implant prosthetic restorations (from the provisional to the definitive restoration.) With this technique, implant soft tissues stability around CAD-CAM (computer aided design - computer aided manufacturing) abutments can be easily obtained, and the customized abutment shape may better support the scalloped peri-implant soft tissues architecture, especially in anterior areas

    Direct ink writing of geopolymeric inks

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    The development of geopolymeric inks with optimized rheological properties for DIW is presented; several inks with different water content and additives were compared to determine which parameters enable extrusion as well as shape retention. It is a challenging task, because the inks are subjected to ongoing poly-condensation reactions which continuously modify their rheological properties over time. Highly porous ceramic lattices (porosity up to 3c71\ua0vol%) were fabricated with 3c0.8\ua0mm struts and unsupported features with very limited sagging. Their physical and mechanical properties were characterized and correlated. Our approach can be successfully extended to other formulations. Geopolymeric foams have recently been proven as suitable for water filtration; the use of precisely designed, non stochastic printed structures could enhance the mechanical properties of the porous components, provide a better control of pressure drop and fluid dynamics inside the part and improve their performances consistently
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