276 research outputs found

    Low-Velocity Impacts on a Polymeric Foam for the Passive Safety Improvement of Sports Fields: Meshless Approach and Experimental Validation

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    Over the past few years, foam materials have been increasingly used in the passive safety of sport fields, to mitigate the risk of crash injury. Currently, the passive safety certification process of these materials represents an expensive and time-consuming task, since a considerable number of impact tests on material samples have to be carried out by an ad hoc testing apparatus. To overcome this difficulty and speed up the design process of new protective devices, a virtual model for the low-velocity impact behaviour of foam protective mats is needed. In this study a modelling approach based on the mesh-free Element Galerkin method was developed to investigate the impact behaviour of ethylene-vinyl acetate (EVA) foam protective mats. The main advantage of this novel technique is that the difficulties related to the computational mesh distortion and caused by the large deformation of the foam material are avoided and a good accuracy is achieved at a relatively low computational cost. The numerical model was validated statistically by comparing numerical and experimental acceleration data acquired during a series of impact events on EVA foam mats of various thicknesses. The findings of this study are useful for the design and improvement of foam protective devices and allow for optimizing sports fields’ facilities by reducing head injury risk by a reliable computational method

    Description of Diegoglossidium maradonai n. g. and n. sp. (Digenea: Alloglossidiidae) through an integrative taxonomy approach, with an amended diagnosis of the family

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    This paper describes Diegloglossidium maradonai n. g., n. sp. a parasite of the intestine of Hoplosternum littorale (Hancock) from La Plata River basin. The new genus is morphologically similar to members of Alloglossidiidae and Macroderoidiidae although they also share some traits observed in both families. Those families can be differentiated from each other by the combination of morphological features, including the density and distribution of the tegumental spines, the distribution of the vitelline follicles and the extent of the post-testicular space. The molecular analyses based on the large subunit of the ribosomal RNA gene, and the internal transcribed spacer (ITS) regions including ITS1, 5.8S and ITS2 unequivocally place the new genus in the family Alloglossidiidae which is amended based on new observed features. Diegoglossidium n. g. is characterized by a combination of characteristics, being most notably the presence of a deeply lobed ovary. Lastly, the geographical distribution and host associations of the two closely related Neotropical genera of Alloglossidiidae: Magnivitellinum and Diegoglossidium are discussed, and the host and distribution range of Magnivitellinum saltaensis is expanded into Argentina.Fil: Montes, Martin Miguel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Estudios Parasitológicos y de Vectores. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Estudios Parasitológicos y de Vectores; ArgentinaFil: Arredondo, Nathalia Jaquelina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Biodiversidad y Biología Experimental y Aplicada. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Biodiversidad y Biología Experimental y Aplicada; ArgentinaFil: Barneche, Jorge Adrian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Estudios Parasitológicos y de Vectores. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Estudios Parasitológicos y de Vectores; ArgentinaFil: Balcazar, Dario Emmanuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Estudios Parasitológicos y de Vectores. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Estudios Parasitológicos y de Vectores; ArgentinaFil: Cardarella, G. Reig. Universidad Bernardo O'higgins; ChileFil: Martorelli, Sergio Roberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Estudios Parasitológicos y de Vectores. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Estudios Parasitológicos y de Vectores; ArgentinaFil: Pérez Ponce de Leon, G. Universidad Nacional Autónoma de México; Méxic

    Morphology and Sequence Data of Mexican Populations of the Ciliate Parasite of Marine Fishes Trichodina rectuncinata (Ciliophora: Trichodinidae)

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    Trichodina rectuncinata is one of the trichodinids most widely distributed in marine fish. This ciliate species has been recorded in more than 20 host species belonging to 17 fish families worldwide. Previous comparative studies based on morphometric data revealed considerable morphological variation among specimens from different populations of T. rectuncinata. In this study, we conducted a morphometric- molecular analysis of three populations of T. rectuncinata to evaluate potential differences among 18S rRNA sequences, in relation to morphological variations. Smears were obtained from marine fishes in three localities along the Pacific coast of Mexico. Based on the shape of denticles, we found four different morphotypes for T. rectuncinata. This morphological variability does not correspond with the genetic divergence, suggesting that all analyzed populations belong to the same species. Further analyses using more variable markers are necessary to corroborate the findings of our study.Centro de Estudios Parasitológicos y de Vectore

    Morphology and Sequence Data of Mexican Populations of the Ciliate Parasite of Marine Fishes Trichodina rectuncinata (Ciliophora: Trichodinidae)

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    Trichodina rectuncinata is one of the trichodinids most widely distributed in marine fish. This ciliate species has been recorded in more than 20 host species belonging to 17 fish families worldwide. Previous comparative studies based on morphometric data revealed considerable morphological variation among specimens from different populations of T. rectuncinata. In this study, we conducted a morphometric- molecular analysis of three populations of T. rectuncinata to evaluate potential differences among 18S rRNA sequences, in relation to morphological variations. Smears were obtained from marine fishes in three localities along the Pacific coast of Mexico. Based on the shape of denticles, we found four different morphotypes for T. rectuncinata. This morphological variability does not correspond with the genetic divergence, suggesting that all analyzed populations belong to the same species. Further analyses using more variable markers are necessary to corroborate the findings of our study.Fil: Islas Ortega, Alma G.. Universidad Nacional Autónoma de México; MéxicoFil: Aguilar Aguilar, Rogelio. Universidad Nacional Autónoma de México; MéxicoFil: Marcotegui, Paula Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Estudios Parasitológicos y de Vectores. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Estudios Parasitológicos y de Vectores; ArgentinaFil: Martorelli, Sergio Roberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Estudios Parasitológicos y de Vectores. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Estudios Parasitológicos y de Vectores; ArgentinaFil: Hernández Mena, David. Universidad Nacional Autónoma de México; MéxicoFil: Pérez Ponce de León, Gerardo. Universidad Nacional Autónoma de México; Méxic

    Morphology and Sequence Data of Mexican Populations of the Ciliate Parasite of Marine Fishes Trichodina rectuncinata (Ciliophora: Trichodinidae)

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    Trichodina rectuncinata is one of the trichodinids most widely distributed in marine fish. This ciliate species has been recorded in more than 20 host species belonging to 17 fish families worldwide. Previous comparative studies based on morphometric data revealed considerable morphological variation among specimens from different populations of T. rectuncinata. In this study, we conducted a morphometric- molecular analysis of three populations of T. rectuncinata to evaluate potential differences among 18S rRNA sequences, in relation to morphological variations. Smears were obtained from marine fishes in three localities along the Pacific coast of Mexico. Based on the shape of denticles, we found four different morphotypes for T. rectuncinata. This morphological variability does not correspond with the genetic divergence, suggesting that all analyzed populations belong to the same species. Further analyses using more variable markers are necessary to corroborate the findings of our study.Centro de Estudios Parasitológicos y de Vectore

    An Integrated Multiscale Method for the Characterisation of Active Faults in Offshore Areas. The Case of Sant\u2019Eufemia Gulf (Offshore Calabria, Italy)

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    Diagnostic morphological features (e.g., rectilinear seafloor scarps) and lateral offsets of the Upper Quaternary deposits are used to infer active faults in offshore areas. Although they deform a significant seafloor region, the active faults are not necessarily capable of producing large earthquakes as they correspond to shallow structures formed in response to local stresses. We present a multiscale approach to reconstruct the structural pattern in offshore areas and distinguish between shallow, non-seismogenic, active faults, and deep blind faults, potentially associated with large seismic moment release. The approach is based on the interpretation of marine seismic reflection data and quantitative morphometric analysis of multibeam bathymetry, and tested on the Sant\u2019Eufemia Gulf (southeastern Tyrrhenian Sea). Data highlights the occurrence of three major tectonic events since the Late Miocene. The first extensional or transtensional phase occurred during the Late Miocene. Since the Early Pliocene, a right-lateral transpressional tectonic event caused the positive inversion of deep (>3 km) tectonic features, and the formation of NE-SW faults in the central sector of the gulf. Also, NNE-SSW to NE-SW trending anticlines (e.g., Maida Ridge) developed in the eastern part of the area. Since the Early Pleistocene (Calabrian), shallow (<1.5 km) NNE-SSW oriented structures formed in a left-lateral transtensional regime. The new results integrated with previous literature indicates that the Late Miocene to Recent transpressional/transtensional structures developed in an 3cE-W oriented main displacement zone that extends from the Sant\u2019Eufemia Gulf to the Squillace Basin (Ionian offshore), and likely represents the upper plate response to a tear fault of the lower plate. The quantitative morphometric analysis of the study area and the bathymetric analysis of the Angitola Canyon indicate that NNE-SSW to NE-SW trending anticlines were negatively reactivated during the last tectonic phase. We also suggest that the deep structure below the Maida Ridge may correspond to the seismogenic source of the large magnitude earthquake that struck the western Calabrian region in 1905. The multiscale approach contributes to understanding the tectonic imprint of active faults from different hierarchical orders and the geometry of seismogenic faults developed in a lithospheric strike-slip zone orthogonal to the Calabrian Arc

    Mid-to-late Holocene upper slope contourite deposits off Capo Vaticano (Mediterranean Sea): High-resolution record of contourite cyclicity, bottom current variability and sandy facies

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    none13noThe upper continental slope offshore Capo Vaticano (southern Tyrrhenian Sea) is characterized by a contourite depositional system with well-developed elongated sediment drifts. This system is related to a northward paleo-bottom current, similar to the present-day modified-Levantine Intermediate Water (modified-LIW) flowing from the Messina Strait. In this work, we show results from an integrated analysis of descriptive oceanography, high-resolution seismic profiles and core data (i.e., grain size, foraminiferal assemblages, tephrostratigraphy and AMS radiocarbon dating) collected from the crest and moat sectors of drift deposits. The studied succession formed since the mid Holocene, under the action of the modified-LIW and the stratigraphic architecture indicates an upslope migration of the moat and rather stable position of the crest sector. Grain-size features recorded from two sediment cores indicate the occurrence of a succession of complete bi-gradational sand-rich contourite sequences. Sandy facies were observed both as lag deposits formed in active moat channel and as coarser intervals of bi-gradational sequences forming drift deposits close to its crest. Their occurrence would highlight that upper slope environments impacted by intermediate water masses and proximal to sandy sources may represent favorable settings for accumulation of sandy sediment. The moat sector is characterized by a more complex stratigraphic record, where either moat sedimentation or lateral deposition of finer sediment occur, suggesting that further investigation is required to better understand this complex element of contourite systems. Based on available age information, some of the bi-gradational sequences probably formed during the Dark Age Cold Period, providing example of a small-scale cyclicity of contourite deposition, likely related to short-term (possibly multicentennial scale) fluctuations of the paleo modified-LIW. According to age constraints and analysis of foraminiferal assemblages, these fluctuations were likely governed by climate variations, with a weaker activity during warmer periods and faster currents during colder events.openMartorelli E., Bosman A., Casalbore D., Chiocci F., Conte A.M., Di Bella L., Ercilla G., Falcini F., Falco P., Frezza V., Gaglianone G., Giaccio B., Mancini M.Martorelli, E.; Bosman, A.; Casalbore, D.; Chiocci, F.; Conte, A. M.; Di Bella, L.; Ercilla, G.; Falcini, F.; Falco, P.; Frezza, V.; Gaglianone, G.; Giaccio, B.; Mancini, M

    Towards Critical Occidentalism Studies: Re-inventing the 'West' and 'Japan' in Mangaesque Popular Cultures

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    This paper investigates the reproduction of the imagined geography of the ‘West’ in contemporary Japan by employing a relational, intersectional and positional approach in order to examine Occidentalism and its hegemonic identification and othering process. Particular attention will be paid to emerging Japanese subcultures enacting a parodic and sexualised re-invention of Westernness and Japaneseness within a globalising mangaesque media mix

    Shiga toxin-producing Escherichia coli (STEC) O22:H8 isolated from cattle reduces E. coli O157:H7 adherence in vitro and in vivo

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    Problem addressed Shiga toxin-producing Escherichia coli (STEC) are a group of bacteria responsible for food-associated diseases. Clinical features include a wide range of symptoms such as diarrhea, hemorrhagic colitis and the hemolytic uremic syndrome (HUS), a life-threatening condition. Objective Our group has observed that animals naturally colonized with STEC strains of unknown serotype were not efficiently colonized with E. coli O157:H7 after experimental infection. In order to assess the basis of the interference, three STEC strains were isolated from STEC persistently-colonized healthy cattle from a dairy farm in Buenos Aires, Argentina. Methods and results The three isolated strains are E. coli O22:H8 and carry the stx1 and stx2d genes. The activatable activity of Stx2d was demonstrated in vitro. The three strains carry the adhesins iha, ehaA and lpfO113. E. coli O22:H8 formed stronger biofilms in abiotic surface than E. coli O157:H7 (eae+, stx2+) and displayed a more adherent phenotype in vitro towards HeLa cells. Furthermore, when both serotypes were cultured together O22:H8 could reduce O157:H7 adherence in vitro. When calves were intragastrically pre-challenged with 108 CFU of a mixture of the three STEC strains and two days later challenged with the same dose of the strain E. coli O157:H7 438/99, the shedding of the pathogen was significantly reduced. Conclusions These results suggest that E. coli O22:H8, a serotype rarely associated with human illness, might compete with O157:H7 at the bovine recto-anal junction, making non-O157 carrying-calves less susceptible to O157:H7 colonization and shedding of the bacteria to the environment.Fil: Martorelli, Luisina. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Patobiología; ArgentinaFil: Albanese, Adriana Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Fisiología y Biofísica Bernardo Houssay. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Fisiología y Biofísica Bernardo Houssay; ArgentinaFil: Vilte, Daniel. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Patobiología; ArgentinaFil: Cantet, Rodolfo Juan Carlos. Universidad de Buenos Aires. Facultad de Agronomía; ArgentinaFil: Bentancor, Adriana Beatriz. Universidad de Buenos Aires. Facultad de Ciencias Veterinarias; ArgentinaFil: Zolezzi, G.. Dirección Nacional de Institutos de Investigación. Administración Nacional de Laboratorios e Institutos de Salud. Instituto Nacional de Enfermedades Infecciosas; ArgentinaFil: Chinen, I.. Dirección Nacional de Institutos de Investigación. Administración Nacional de Laboratorios e Institutos de Salud. Instituto Nacional de Enfermedades Infecciosas; ArgentinaFil: Ibarra, Cristina Adriana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Fisiología y Biofísica Bernardo Houssay. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Fisiología y Biofísica Bernardo Houssay; ArgentinaFil: Rivas, M.. Dirección Nacional de Institutos de Investigación. Administración Nacional de Laboratorios e Institutos de Salud. Instituto Nacional de Enfermedades Infecciosas; ArgentinaFil: Mercado, Elsa Cristina. Instituto Nacional de Tecnología Agropecuaria. Centro Nacional de Investigaciones Agropecuarias Castelar. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Patobiología; ArgentinaFil: Cataldi, Ángel Adrián. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Biotecnología; Argentin

    The Bortoluzzi Mud Volcano (Ionian Sea, Italy) and its potential for tracking the seismic cycle of active faults

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    The Ionian Sea in southern Italy is at the center of active interaction and convergence between the Eurasian and African-Adriatic plates in the Mediterranean. This area is seismically active with instrumentally and/or historically recorded Mw > 7:0 earthquakes, and it is affected by recently discovered long strike-slip faults across the active Calabrian accretionary wedge. Many mud volcanoes occur on top of the wedge. A recently discovered one (called the Bortoluzzi Mud Volcano or BMV) was surveyed during the Seismofaults 2017 cruise (May 2017). High-resolution bathymetric backscatter surveys, seismic reflection profiles, geochemical and earthquake data, and a gravity core are used here to geologically, geochemically, and geophysically characterize this structure. The BMV is a circular feature ' 22 m high and ' 1100 m in diameter with steep slopes (up to a dip of 22). It sits atop the Calabrian accretionary wedge and a system of flower-like oblique-slip faults that are probably seismically active as demonstrated by earthquake hypocentral and focal data. Geochemistry of water samples from the seawater column on top of the BMV shows a significant contamination of the bottom waters from saline (evaporite-type) CH4-dominated crustal-derived fluids similar to the fluids collected from a mud volcano located on the Calabria mainland over the same accretionary wedge. These results attest to the occurrence of open crustal pathways for fluids through the BMV down to at least the Messinian evaporites at about-3000 m. This evidence is also substantiated by helium isotope ratios and by comparison and contrast with different geochemical data from three seawater columns located over other active faults in the Ionian Sea area. One conclusion is that the BMV may be useful for tracking the seismic cycle of active faults through geochemical monitoring. Due to the widespread diffusion of mud volcanoes in seismically active settings, this study contributes to indicating a future path for the use of mud volcanoes in the monitoring and mitigation of natural hazards
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