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Browsing Publicaciones by Subject "Ciencias Exactas y Naturales"

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    Enteroparasitosis en una población infantil del municipio de Hurlingham, Buenos Aires
    (Fundación Revista Medicina, 2022) de la Fourniere, Sofía Ana María.; Helman, María Elisa; Consiglio, Ezequiel; Etchemendi, Sebastián; Farber, Marisa Diana; López Arias, Ludmila Sol
    Los parásitos intestinales tienen mayor impacto en las poblaciones infantiles ya que pueden, a largo plazo, conducir a un retraso en el crecimiento con alteración del desarrollo cognitivo. Sumado a esto, los entornos de vulnerabilidad social favorecen la transmisión y permanencia de estos parásitos en el ambiente. Métodos: En un estudio transversal realizado en el Municipio de Hurlingham (conurbano bonaerense) se estimó la prevalencia de enteroparasitosis y sus factores de riesgo asociados en una población infantil concurrente a Centros de Atención Primaria para la Salud locales mediante un análisis coproparasitológico, un test de Graham y una encuesta socioambiental y laboral. Resultados: Un total de 66 niñas (50.8%) y 64 niños (49.2%) entre 0 a 12 años fueron analizados. El 89.1% de los mayores de 4 años estaban escolarizados. En el 28.5% de los hogares la madre o el padre tenía trabajo formal y el 63.8% percibía la asignación universal por hijo (AUH). Se observaron condiciones de vulnerabilidad social en la población analizada, tales como: falta de acceso al agua de red y cloacas y un saneamiento ambiental deficiente. El diagnóstico parasitológico reveló un total de 75 casos [57.7% (IC 95%: 48.7-66.3)] de parasitosis. Los protistas fueron los parásitos más frecuentes y las especies más prevalentes: Blastocystis spp, Enterobius vermicularis, Giardia lamblia y Cryptosporidium sp. La presencia de parásitos estuvo asociada a la escolarización (p<0.01) y a la edad del niño (p<0.05). Discusión: Este fue el primer relevamiento sobre las enteroparasitosis en el municipio de Hurlingham y el contexto socioeconómico y ambiental donde se desarrollan.
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    Nodal and churchill1 position the expression of a notch ligand during Xenopus germ layer segregation
    (2022) Favarolo, María Belén; Revinski, Diego R.; López, Silvia L.; Garavaglia, Matías
    In vertebrates, Nodal signaling plays a major role in endomesoderm induction, but germ layer delimitation is poorly understood. In avian embryos, the neural/mesoderm boundary is controlled by the transcription factor CHURCHILL1, presumably through the repressor ZEB2, but there is scarce knowledge about its role in other vertebrates. During amphibian gastrulation, Delta/Notch signaling refines germ layer boundaries in the marginal zone, but it is unknown the place this pathway occupies in the network comprising Churchill1 and Nodal. Here, we show that Xenopus churchill1 is expressed in the presumptive neuroectoderm at mid-blastula transition and during gastrulation, upregulates zeb2, prevents dll1 expression in the neuroectoderm, and favors neuroectoderm over endomesoderm development. Nodal signaling prevents dll1 expression in the endoderm but induces it in the presumptive mesoderm, from where it activates Notch1 and its target gene hes4 in the non-involuting marginal zone. We propose a model where Nodal and Churchill1 position Dll1/Notch1/Hes4 domains in the marginal zone, ensuring the delimitation between mesoderm and neuroectoderm.
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    The educational community and its knowledge and perceptions of native and invasive alien species
    (2021) Sosa, Alejandro Joaquín; Jiménez, Nadia Lis; Faltlhauser, Ana Claudia; Righetti, Tomás; Mc Kay, Fernando; Bruzzone, Octavio Augusto; Stiers, Iris; Fernández Souto, Adriana Beatríz
    Environmental education seeks to foster an appreciation for nature and the impact of humans on it while introducing citizens to scientifc thinking. Tiological invasions afect diferent aspects of life on earth and mandate urgent management actions. Education and public awareness are strongly recommended for successful prevention and management of invasive alien species (IAS). This work presents a study on knowledge and perception of the educational community of Argentina about native species and IAS. We designed an on-line semi-structured questionnaire to examine perception of the environment, recognition of native species and IAS and awareness about biological invasions. Educators recognised an important number of biotic components, mostly represented by trees, birds and mammals. Recognition of native species and IAS, and awareness of biological invasions were diferent between NST (Natural Science Teachers) and non-NST. Respondents had diferent performances when they were exposed to recognising native species though written names or photographs. Out of 532 respondents, 56% knew what biological invasions are, 21% answered “Maybe” and 23% had never heard about them. We need to foster capacity-building and encourage a two-way communication between educators and scientists, formally and informally, to engage the participation of the whole society in recognition, prevention and management of IAS.
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    Transient and asymmetric dust structures in the TeV-bright nova RS Oph revealed by spectropolarimetry
    (EDP Sciences, 2023) Nikolov, Y.; Luna, Gerardo Juan Manuel; Stoyanov, K. A.; Borisov, G.; Mukai, K.; Sokoloski, J. L.; Avramova Boncheva, A.
    A long-standing question related to nova eruptions is how these eruptions might lead to dust formation, despite the ostensibly inhospitable environment for dust within the hot, irradiated ejecta. In the novae of systems such as the symbiotic binary RS Ophiuchi (RS Oph), ejecta from the white dwarf collide with pre-existing circumstellar material fed by the wind from the red-giant companion, offering a particularly clear view of some nova shocks and any associated dust production. In this work, we use the spectropolarimetric monitoring of the recurrent nova RS Oph starting two days after its eruption in August 2021 to show that: 1) dust was present in the RS Oph system as early as two days into the 2021 eruption; 2) the spatial distribution of this early dust was asymmetric, with components both aligned with and perpendicular to the orbital plane of the binary; 3) between two and nine days after the start of the eruption, this early dust was gradually destroyed; and 4) dust was again created, aligned roughly with the orbital plane of the binary more than 80 days after the start of the outburst, most likely as a result of shocks that arose as the ejecta interacted with circumbinary material concentrated in the orbital plane. The modeling of X-rays and very-high-energy (GeV and TeV) emission from RS Oph days to months into the 2021 eruption suggests that collisions between the ejecta and the circumbinary material may have led to shock formation in two distinct regions: the polar regions perpendicular to the orbital plane, where collimated outflows have been observed after prior eruptions, and a circumbinary torus in the orbital plane. The observations described here indicate that dust formed in approximately the same two regions, supporting the connection between shocks and dust in novae and revealing a very early onset of asymmetry. The spectropolarimetric signatures of RS Oph in the first week into the 2021 outburst indicate: 1) polarized flux across the Hα emission line and 2) the position angle orientation relative to the radio axis is similar to what is seen from the spectropolarimetric signatures of active galactic nuclei (AGNs)