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A new variety of Solanum sisymbriifolium obtained by in vitro polyploidization
(2024)
A non-traditional fluid problem: transition between theoretical models from Stokes’ to turbulent flow
(IOP Science, 2018) Salomone, Horacio D.; Olivieri, Néstor A.; Raviola, Lisandro A.; Véliz, Maximiliano Ezequiel
In the context of fluid mechanics courses, it is customary to consider the problem of a sphere falling under the action of gravity inside a viscous fluid. Under suitable assumptions, this phenomenon can be modelled using Stokes' law and is routinely reproduced in teaching laboratories to determine terminal velocities and fluid viscosities. In many cases, however, the measured physical quantities show important deviations with respect to the predictions deduced from the simple Stokes' model, and the causes of these apparent'anomalies'(for example, whether the flow is laminar or turbulent) are seldom discussed in the classroom. On the other hand, there are various variable-mass problems that students tackle during elementary mechanics courses and which are discussed in many textbooks. In this work, we combine both kinds of problems and analyse—both theoretically and experimentally—the evolution of a system composed of a sphere pulled by a chain of variable length inside a tube filled with water. We investigate the effects of different forces acting on the system such as weight, buoyancy, viscous friction and drag force. By means of a sequence of mathematical models of increasing complexity, we obtain a progressive fit that accounts for the experimental data. The contrast between the various models exposes the strengths and weaknessess of each one. The proposed experience can be useful for integrating concepts of elementary mechanics and fluids, and is suitable as laboratory practice, stressing the importance of the experimental validation of theoretical models and showing the model-building processes in a didactic framework.
An Intrinsically Explainable Method to Decode P300 Waveforms from EEG Signal Plots Based on Convolutional Neural Networks
(2024) Ail, B.E.; Ramele, R.; Gambini, J.; Santos, J.M.
Ancient varieties can help control weed density while preserving weed diversity
(2023) Federico, Ana Ailén; Pimet, Eric; Arnaud Coffin, Chantal; Ducourtieux, Wilfried
Anthropogenic Infection of Domestic Cats With SARS-CoV-2 Alpha Variant B.1.1.7 Lineage in Buenos Aires
(Frontiers Media, 2022) Pecora, Andrea; Malacari, Darío Amílcar; Mozgovoj, Marina Valeria; Díaz, María de los Ángeles; Peralta, Andrea Verónica; Cacciabue, Marco Polo Domingo; Puebla, Andrea Fabiana; Carusso, Cristian; Mundo, Silvia Leonor; González López Ledesma, María Mora; Gamarnik, Andrea Vanesa
SARS-CoV-2 reverse zoonosis, particularly to domestic animals, and the potential role of infected animals in perpetuating the spread of the virus is an issue of increasing concern. In this case report, we identified the natural infection of two cats by SARS-CoV-2, in Argentina, whose owner had been previously infected by SARS-CoV-2. Viral genetic material was detected in feline oropharyngeal (OP) and rectal (R) swab by RT-qPCR, and sequence analysis revealed that the virus infecting the owner and one cat were genetically similar. The alpha variant (B.1.1.7 lineage) was identified with a unique additional mutation, strongly suggesting human-to-cat route of transmission. This study reinforces the One Health concept and the importance of integrating human, animal, and environmental perspectives to promptly address relevant health issues.
Assessing small RNA profiles in potato diploid hybrid and its resynthesized allopolyploid reveals conserved abundance with distinct genomic distribution
(2024) Zavallo, D.; Cara, N.; Leone, M.
Asymptotic Distribution of Certain Types of Entropy under the Multinomial Law
(2023) Rey, A.A.; Frery, A.C.; Lucini, M.; Gambini, J.; Chagas, E.T.C.; Ramos, H.S.
Average-case complexity of the Euclidean algorithm with a fixed polynomial over a finite field
(Cambridge University Press, 2021) Giménez, Nardo; Matera, Guillermo; Pérez, Mariana Valeria; Privitelli, Melina Lorena
We analyse the behaviour of the Euclidean algorithm applied to pairs (g,f) of univariate nonconstant polynomials over a finite field Fq of q elements when the highest degree polynomial g is fixed. Considering all the elements f of fixed degree, we establish asymptotically optimal bounds in terms of q for the number of elements f that are relatively prime with g and for the average degree of gcd(g,f) . We also exhibit asymptotically optimal bounds for the average-case complexity of the Euclidean algorithm applied to pairs (g,f) as above.
Breaking the Degeneracy in Magnetic Cataclysmic Variable X-Ray Spectral Modeling Using X-Ray Light Curves
(IOP Publishing, 2022) Belloni, Diogo; Luna, Gerardo Juan Manuel
We present an analysis of mock X-ray spectra and light curves of magnetic cataclysmic variables using an upgraded version of the 3D cyclops code. This 3D representation of the accretion flow allows us to properly model total and partial occultation of the postshock region by the white dwarf as well as the modulation of the X-ray light curves due to the phase-dependent extinction of the preshock region. We carried out detailed postshock region modeling in a four-dimensional parameter space by varying the white dwarf mass and magnetic field strength as well as the magnetosphere radius and the specific accretion rate. To calculate the postshock region temperature and density profiles, we assumed equipartition between ions and electrons; took into account the white dwarf gravitational potential, the finite size of the magnetosphere, and a dipole-like magnetic field geometry; and considered cooling by both bremsstrahlung and cyclotron radiative processes. By investigating the impact of the parameters on the resulting X-ray continuum spectra, we show that there is an inevitable degeneracy in the four-dimensional parameter space investigated here, which compromises X-ray continuum spectral fitting strategies and can lead to incorrect parameter estimates. However, the inclusion of X-ray light curves in different energy ranges can break this degeneracy, and it therefore remains, in principle, possible to use X-ray data to derive fundamental parameters of magnetic cataclysmic variables, which represents an essential step toward understanding their formation and evolution.
Chandra High Energy Transmission Gratings Spectra of V3890 Sgr
(IOP Publishing, 2020) Orio, M.; Drake, J. J.; Ness, J. U.; Behar, E.; Darnley, M. J; Gallagher, J; Kuin, N. P. M; Luna, Gerardo Juan Manuel
The recurrent nova (RN) V3890 Sgr was observed during the seventh day after the onset of its most recent outburst, with the Chandra ACIS-S camera and High Energy Transmission Gratings. A rich emission line spectrum was detected, due to transitions of Fe-L and K-shell ions ranging from neon to iron. The measured absorbed flux is ≈10−10 erg cm−2 s −1 in the 1.4–15 Å range (0.77–8.86 keV). The line profiles are asymmetric, blueshifted, and skewed toward the blue side, as if the ejecta moving toward us are less absorbed than the receding ejecta. The full width at half-maximum of most emission lines is 1000–1200 km s−1 , with some extended blue wings. The spectrum is thermal and consistent with a plasma in collisional ionization equilibrium with column density 1.3 × 1022 cm−2 and at least two components at temperatures of about 1 and 4 keV, possibly a forward and a reverse shock, or regions with differently mixed ejecta and a red giant wind. The spectrum is remarkably similar to the symbiotic RNe V745 Sco and RS Oph, but we cannot distinguish whether the shocks occurred at a distance of a few au from the red giant, or near the giant’s photosphere, in a high-density medium containing only a low mass. The ratios of the flux in lines of aluminum, magnesium, and neon relative to the flux in lines of silicon and iron probably indicate a carbon–oxygen white dwarf.
Complete genome sequence of deformed wing virus and black queen cell virus isolated from honeybees (Apis mellifera) in Argentina
(2024) González, Fernanda N.; Ferrufino, Cecilia; Dus Santos, María José; Carignano, Hugo A.
We report the complete genome sequence of deformed wing virus and black queen cell virus isolated from Argentinean’s honeybees. These sequence data will be valuable for future research on the viral variants present in the country and the development of strategies to control the spread of these viruses in apiaries.
Cooperativity in regulation of membrane protein function : phenomenological analysis of the effects of pH and phospholipids
(2023) Zerbetto De Palma, G; Recoulat Angelini, A.A.; Vitali, V.
Cost-Effective Method to Perform SARS-CoV-2 Variant Surveillance: Detection of Alpha, Gamma, Lambda, Delta, Epsilon, and Zeta in Argentina :
(Frontiers Media, 2021) Torres, Carolina; Mojsiejczuk, Laura Noelia; Acuña, Dolores; Alexay, Sofía; Dus Santos, María José; Amadio, Ariel Fernando
SARS-CoV-2 variants with concerning characteristics have emerged since the end of 2020. Surveillance of SARS-CoV-2 variants was performed on a total of 4,851 samples from the capital city and 10 provinces of Argentina, during 51 epidemiological weeks (EWs) that covered the end of the first wave and the ongoing second wave of the COVID-19 pandemic in the country (EW 44/2020 to EW 41/2021). The surveillance strategy was mainly based on Sanger sequencing of a Spike coding region that allows the identification of signature mutations associated with variants. In addition, whole-genome sequences were obtained from 637 samples. The main variants found were Gamma and Lambda, and to a lesser extent, Alpha, Zeta, and Epsilon, and more recently, Delta. Whereas, Gamma dominated in different regions of the country, both Gamma and Lambda prevailed in the most populated area, the metropolitan region of Buenos Aires. The lineages that circulated on the first wave were replaced by emergent variants in a term of a few weeks. At the end of the ongoing second wave, Delta began to be detected, replacing Gamma and Lambda. This scenario is consistent with the Latin American variant landscape, so far characterized by a concurrent increase in Delta circulation and a stabilization in the number of cases. The cost-effective surveillance protocol presented here allowed for a rapid response in a resource-limited setting, added information on the expansion of Lambda in South America, and contributed to the implementation of public health measures to control the disease spread in Argentina.
Crop diversity improves carbon, nitrogen and soil biological functions in an agroecological system
(2023) Ortíz, J.; Faggioli, V.; Zamora, M.; Boccolini, M.; Lorenzón, C.; Pegoraro, V.; Gabbarini, L.
Definition of the Emmallodera perlifera Species Group (Coleoptera: Tenebrionidae: Scotobiini) from Argentina with Descriptions of Two New Species
(Polish Academy of Sciences, 2022) Silvestro, Violeta Ayelen; Macagno, Hilda Beatríz; Flores, Gustavo Ernesto
The genus Emmallodera Blanchard, 1842 (Tenebrionidae: Scotobiini) is widely distributed in western and southern Argentina and partially in southern Chile, inhabiting the biogeographic provinces Patagonian, Chacoan and Monte. The genus Emmallodera is well characterized within Scotobiini by the presence of a single spine on the profemur of its species, as well as by having pointed terminal antennomeres, and the tarsomeres loosely articulated to each other. Within the genus, E. perlifera Burmeister, 1875 is the largest species and is the only one characterized by the presence of tubercles on elytral intervals. Analysis of the recently collected specimens resulted in discovery of two new species (E. payunia Silvestro and Flores sp. nov. and E. andina Silvestro and Macagno sp. nov.), which share the main diagnostic features of E. perlifera but possess enough differences in elytral configuration and male genitalia to confirm that they are not conspecific. Under a deep morphological revision, it can be concluded that all of the three above-mentioned species constitute a well-characterized species-group inside the genus Emmallodera, while each of these taxa inhabits different biogeographic provinces, i.e.: Emmallodera perlifera (Monte and Chaco), E. payunia Silvestro and Flores sp. nov. (Patagonian) and E. andina Silvestro and Macagno sp. nov. (Puna). This paper includes taxonomic characterization of the group, designation of lectotype for E. perlifera, descriptions of the two new species, habitus photographs, illustrations of genital features and a distribution map.
Detección de SARS-CoV-2 en contactos estrechos asintomáticos de casos confirmados por diagnóstico molecular, provincia de Buenos Aires, Argentina
(2021) Fischerman, L.; Ercole, R.; Mozgovoj, M.; Dus Santo, M.J.; Didier Garnham, M.; Lemes Lenivov, F.; Benvenutti, M.L.; Santana, L.
Detection of porcine circovirus 2, porcine parvovirus 1, and torque teno sus virus k2a in wild boars from northeastern Patagonia, Argentina
(2023) De Maio, F.A.; Winter, M.; Abate, S.; Iglesias, N.G.
Development and standardization of an enzyme-linked inmunosorbent for the detection of orthohantavirus infection in Argentina based on its bacterial-expressed nucleocapside protein
(2024) Muzulin, P.; Brignone, J.; Iglesias, N.G.; Rodríguez, M.; Irazu, L.; García, J. B.; Levis, S.
Diversidad de cultivos mejora el carbono, nitrogeno y las funciones biológicas del suelo en un sistema agroecologico.
(2023) Ortíz, J.; Faggioli, V.; Zamora, M.; Boccolini, M.; Lorenzón, C.; Pegoraro, V.; Gabbarini, L.
Enteroparasitosis en una población infantil del municipio de Hurlingham, Buenos Aires
(Fundación Revista Medicina, 2022) López Arias, Ludmila Sol; de la Fourniere, Sofía Ana María; Helman, María Elisa; Consiglio, Ezequiel; Etchemendi, Sebastián; Farber, Marisa Diana
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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