Necesidad y alcance de la matemática en las ciencias sociales

Los científicos sociales destacan la creciente necesidad de matematización en la construcción de modelos y teorías. Consideramos que la Matemática elemental, la Estadística descriptiva y la Lógica clásica, utilizadas en las investigaciones, se muestran insuficientes y requieren el aporte de nuevos conocimientos. Estas reflexiones se enmarcan teóricamente en los límites de la Socio epistemología contemporánea, que incluye la Teoría de las Representaciones Sociales. Su utilización es de rigurosa actualidad en investigaciones relacionadas con la educación, ya que una Representación Social es un potente instrumento teórico para conocer la manera en que se construyen las ideas compartidas en las comunidades y la incorporación del conocimiento del sentido común al ámbito científico. Nuestro objetivo es mostrar la utilidad de los conocimientos lógico-matemáticos en la construcción de teorías Económicas, consideradas en la actualidad la más matematizada de las Ciencias Sociales

Correlations between Elastic, Calorimetric, and Polar Properties of Ferroelectric PbSc0.5Ta0.5O3 (PST)

Calorimetric, elastic, and polar properties of ferrolectric lead scandium tantalate PbSc0.5Ta0.5O3 (PST) with 65% cation order have been investigated in the vicinity of the paraelectric-ferroelectric transition at Ttrans = 295K. Comparison of temperature dependencies of the excess specific heat and elastic properties indicate that both anomalies stem from ther- mal fluctuations of order parameters in three dimensions. These fluctuations are consistent with tweed microstructure. This transition is driven by several coupled thermodynamic order parameters, as evidenced by a strongly non-linear scaling of the excess entropy with the squared ferroelectric polarization.National Natural Science Foundation of China (51850410520, 51320105014 and 51621063

Breast cancer analysis by confocal energy dispersive micro-XRD

In this work, the confocal energy dispersive micro-XRD technique has been employed to efficiently study differences between normal and malignant carcinomas in breast tissues. This technique has been implemented with low angular divergence glass monocapillaries in the excitation and detection channels. The microdiffractometer operates with a scattering angle of (20.3 ± 0.9)° that defines a cross section for analysis (0.178 mm × 0.175 mm), with a depth resolution of 1.18 mm. The obtained momentum transfer resolution between 3.9 and 10.9% was found to be highly useful to identify the scattering profiles of adipose tissues without any data processing. Differentiation between tissues with similar scattering profiles, such as fibroglandular and neoplastic tissues, has been achieved by processing the spectra within the framework of diffraction theory for scattering intensity. The obtained results allowed the development of a deterministic diagnostic model based on the evaluation of the depth profiles by confocal micro-XRD. In this model, the modulation of the scattering profiles caused by X-ray attenuation was analyzed to differentiate neoplastic tissues. The spatial resolution of the technique was the key aspect of the process, helping to detect variations in X-ray attenuation and to select uniform volume of analysis without superimposed scattering profiles.Fil: Escudero, Rodrigo Oscar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; ArgentinaFil: Cabral, María C.. Hospital Provincial Maternal Dr. Felipe Lucini; ArgentinaFil: Valladares, Mariana. Hospital Provincial Maternal Dr. Felipe Lucini; ArgentinaFil: Franco, María A.. Hospital Provincial Maternal Dr. Felipe Lucini; ArgentinaFil: Perez, Roberto Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; Argentin

Evaluation of Cytotoxicity and Genotoxicity of Acacia aroma Leaf Extracts

Acacia aroma, native plant from San Luis, Argentina, is commonly used as antiseptic and for healing of wounds. The present study was conducted to investigate the in vitro cytotoxicity and genotoxicity of hot aqueous extract (HAE) and ethanolic extract (EE) of A. aroma. The cytotoxic activity was assayed by neutral red uptake assay on Vero cell. Cell treatment with a range from 100 to 5000 g/mL of HAE and EE showed that 500 g/mL and 100 g/mL were the maximum noncytotoxic concentrations, respectively. The CC50 was 658 g/mL for EE and 1020 g/mL for HAE. The genotoxicity was tested by the single-cell gel electrophoresis comet assay. The results obtained in the evaluation of DNA cellular damage exposed to varied concentrations of the HAE showed no significant genotoxic effect at range of 1–20 mg/mL. The EE at 20 mg/mL showed moderate genotoxic effect related to the increase of the DNA percentage contained in tail of the comet; DNA was classified in category 2. At concentrations below 5 mg/mL, the results of cytotoxicity and genotoxicity of aqueous and ethanolic extracts of Acacia aroma guarantee the safety at cell and genomic level. However further studies are needed for longer periods including animal models to confirm the findings.Fil: Mattana, Claudia Maricel. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia; ArgentinaFil: Cangiano, Maria de Los Angeles. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Alcaraz, María Luciana. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Sosa, A.. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia; ArgentinaFil: Escobar, Franco Matias. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Sabini, C.. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales; ArgentinaFil: Sabini, Liliana Ines. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales; ArgentinaFil: Laciar, Analia Liliana. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia; Argentin

Dynamics of HeHHe+ Rotational State Changes Induced by Collision with He: A Possible New Path in Early Universe Chemistry

[EN]Ab initio calculations are employed to generate the rigid rotor (RR) potential energy surface (PES) describing the interaction of the linear molecular cation HeHHe+, at its equilibrium geometry, with the neutral He atom. The resulting interaction is employed to investigate the efficiency of rotational state-changing collisions at the temperatures relevant to the early universe conditions, where the latter molecule has been postulated to exist, albeit not yet observed. The inelastic rate coefficients are found to be fairly large and are compared with those found for another important cation just recently observed in the interstellar medium: the HeH+ polar molecule. The possibility for this cation to provide new options to energy dissipation routes under early universe conditions after the recombination era is briefly discussed

Magneto-caloric effect in the pseudo-binary intermetallic YPrFe17 compound

We have synthesized the intermetallic YPrFe17 compound by arc-melting. X-ray and neutron powder diffraction show that the crystal structure is rhombohedral with View the MathML source space group (Th2Zn17-type). The investigated compound exhibits a broad isothermal magnetic entropy change {\Delta}SM(T) associated with the ferro-to-paramagnetic phase transition (TC \approx 290 K). The |{\Delta}SM| (\approx 2.3 J kg-1 K-1) and the relative cooling power (\approx 100 J kg-1) have been calculated for applied magnetic field changes up to 1.5 T. A single master curve for {\Delta}SM under different values of the magnetic field change can be obtained by a rescaling of the temperature axis. The results are compared and discussed in terms of the magneto-caloric effect in the isostructural R2Fe17 (R = Y, Pr and Nd) binary intermetallic alloys.Comment: Preprint, 5 pages (postprint), 4 figures, regular pape

Paving the way for adequate myelination: The contribution of galectin-3, transferrin and iron

AbstractConsidering the worldwide incidence of well characterized demyelinating disorders such as Multiple Sclerosis (MS) and the increasing number of pathologies recently found to involve hypomyelinating factors such as micronutrient deficits, elucidating the molecular basis of central nervous system (CNS) demyelination, remyelination and hypomyelination becomes essential to the development of future neuroregenerative therapies. In this context, this review discusses novel findings on the contribution of galectin-3 (Gal-3), transferrin (Tf) and iron to the processes of myelination and remyelination and their potentially positive regulation of oligodendroglial precursor cell (OPC) differentiation. Studies were conducted in cuprizone (CPZ)-induced demyelination and iron deficiency (ID)-induced hypomyelination, and the participation of glial and neural stem cells (NSC) in the remyelination process was evaluated by means of both in vivo and in vitro assays on primary cell cultures

Understanding hydrodechlorination of chloromethanes. Past and future of the technology

Chloromethanes are a group of volatile organic compounds that are harmful to the environment and human health. Abundant studies have verified that hydrodechlorination might be an effective treatment to remove these chlorinated pollutants. The most outstanding advantages of this technique are the moderate operating conditions used and the possibility of obtaining less hazardous valuable products. This review presents a global analysis of experimental and theoretical studies regarding the hydrodechlorination of chloromethanes. The catalysts used and their synthesis methods are summarized. Their physicochemical properties are analyzed in order to deeply understand their influence on the catalytic performance. Moreover, the main causes of the catalyst deactivation are explained, and prevention and regeneration methods are suggested. The reaction systems used and the effect of the operating conditions on the catalytic activity are also analyzed. Besides, the mechanisms and kinetics of the process at the atomic level are reviewed. Finally, a new perspective for the upgrading of chloromethanes, via hydrodechlorination, to valuable hydrocarbons for industry, such as light olefins, is discussedThe authors gratefully acknowledge financial support through research projects SI1/PJI/2019-00487 (Comunidad de Madrid/UAM) and CTM2017-85498-R (FEDER/Ministerio de Ciencia, Innovación y Universidades-Agencia Estatal de Investigación). M. Martín Martínez acknowledges a postdoctoral grant, 2017-T2/AMB-5668, from the Comunidad de Madrid “Atracción de talento investigador” programme. S. Liu acknowledges MINECO for his research grant PRE2018-08442

Effects of salinity and B excess on the growth, photosynthesis, water relation and mineral composition of laurustinus grown in greenhouse

Trabajo presentado en el XXVIII International Horticultural Congress on Science and Horticulture for People (IHC2010): International Symposium on Greenhouse 2010 and Soilless Cultivation, celebrado en Lisboa, Portugal, del 22 al 27 de agosto de 2010A greenhouse study was conducted to determine the interactive effects of NaCl salinity and boron on the growth, plant water status, gas exchange, chlorophyll fluorescence and concentrations of sodium (Na), chloride (Cl) and boron (B) in laurustinus (Viburnum tinus L.). Potted plants were grown in a factorial combination of salinity (2 and 6 dS m-1) and boron (1 and 6 mg L-1). Plant dry weight (DW) decreased with salinity and B excess, particularly as a result of the former. The salinity × B interaction on the plant DW was not significant (additive effects). Salinity increased Na and Cl concentrations in leaf (20 and 35 mg g-1 DW, respectively) resulting in foliar injury. The application of 6 mg L-1 of B (B toxicity or B excess) produced injury symptoms in old leaves (leaf tip and edge burn). Salinity and B toxicity led to leaves dropping, especially the former. B toxicity led to higher B concentrations in insured leaves (1385 mg kg-1 DW) and salinity reduced it to 425 (B x NaCl antagonistic effect). Boron excess did no alter Na and Cl concentrations in leaf. Salinity decreased stomatal conductance (gs) as a regulatory mechanism against osmotic stress, which resulted in a dropping photosynthesis (Pn). Leaf water parameters were only affected by salinity, which enhanced a process of osmotic adjustment and improving the plant water status. Salt-stressed plants showed an adaptive response to salinity, which decreased gs, Pn and quantum yield of photosystem II (éPSII), and dissipated the excess radiant energy as heat (increased non-photochemical quenching [NPQ]). The combination of salinity and B excess maintained éPSII and decreased the effectiveness of stomatal regulation, NPQ and Pn. This caused the lowest plant DW and suggests disorders in electron transport (photorespiration). Our findings suggest that: (1) laurustinus is a B excess sensitive species, (2) salinity reduced the accumulation of B in leaves of the B excess stressed plants but was not enough to prevent injuries in PSII, and (3) B excess or/and salinity provide plants of poor commercial quality.This research was supported by CICYT projects (CICYT AGL2008-05258-CO2- 1-AGR and CICYT AGL2008-05258-CO2-2-AGR), SENECA project (08669/PI/08) and by the Consejería de Agricultura y Agua de la Región de Murcia, program (UPCTCEBAS- IMIDA 2008).Peer Reviewe