Evaluación de los efectos genotóxicos del herbicida 2,4-D en Piaractus mesopotamicus a través del test de micronúcleos

The herbicide 2,4-D is currently one of the most used agrochemicals in agriculture. The fish are target of contamination, these when being in contact with toxics develop later alterations that can be studied, reason why they are used as models in the evaluation of aquatic ecosystems. There is scarce information about the effects of these pesticides in fish. Because of this, the objective of this work was to evaluate the possible impact of a contamination with 2,4-D, in sub-lethal concentrations in Piaractus mesopotamicus, through the frequency of micronuclei (MN) and alterations in the shape of the nuclei (NMA) in peripheral blood erythrocytes in chronic conditions (70 days). Two trials were conducted, one with the herbicide 2,4-D pure (P) and another with a commercial formulation (2,4-D bitter amine) (FC). Each experience was composed of five aquariums with two specimens in each, where different concentrations of the pesticide were administered (1 ppm, 1.8 ppm, 3.2 ppm, 5.6 ppm and 10 ppm), and in another with well water (control). A total of 4000 cells per individual were analyzed. Through the test MN and NMA the presence of diverse nuclear alterations was evidenced. The mentioned test for P and dilutions 1 ppm, 1.8 ppm, 3.2 ppm, 5.6 ppm of FC did not show significant differences with the control, while the concentration of 10 ppm of FC differed statistically from its control, this could be due to additional components in FC.Los herbicidas están siendo abundantemente utilizados haciendo que los mismos no solo lleguen al organismo específico sino también contaminen el medio ambiente donde son empleados. El herbicida 2,4-D es en la actualidad uno de los agroquímicos más utilizado en la agricultura. Los peces son blanco de la contaminación, éstos al estar en contacto con tóxicos desarrollan posteriormente alteraciones que pueden ser estudiadas, por lo cual son utilizados como modelos en la evaluacion de ecosistemas acuáticos. Existe escasa información acerca de los efectos de estos pesticidas en peces, siendo el actual trabajo el primero en evaluar efectos crónicos. El objetivo de la presente investigación fue evaluar el posible impacto de una contaminación con 2,4-D en concentraciones subletales en Piaractus mesopotamicus, a través de la frecuencia de micronúcleos (MN) y de las alteraciones en la forma de los núcleos (NMA) en eritrocitos de sangre periférica en condiciones crónicas (70 días). Se realizaron dos ensayos, uno con el herbicida 2,4-D puro (P) y otro con una formulación comercial (2,4-D amina Sumargo) (FC). Cada experiencia estuvo compuesta por cinco acuarios con dos ejemplares en cada uno, donde se administraron difererentes concentraciones del plaguicida (1 ppm, 1,8 ppm, 3,2 ppm, 5,6 ppm y 10 ppm), y en otra con agua de pozo (control). Se analizó un total de 4000 células por individuo. A través del test MN y NMA se evidenció la presencia de diversas alteraciones nucleares. El mencionado test para P y las diluciones 1 ppm, 1,8 ppm, 3,2 ppm, 5,6 ppm de FC no mostraron diferencias significativas con el control, mientras que la concentración de 10 ppm de FC se diferenció estadísticamente de su control. El presente trabajo aporta luz de los potenciales efectos nocivos del 2,4-D en el medio ambiente y posibilita nuevos estudios prospectivos y retrospectivos

Revealing hidden symmetries and gauge invariance of the massive Carroll-Field-Jackiw model

In this paper we have analyzed the improved version of the Gauge Unfixing (GU) formalism of the massive Carroll-Field-Jackiw model, which breaks both the Lorentz and gauge invariances, to disclose hidden symmetries to obtain gauge invariance, the key stone of the Standard Model. In this process, as usual, we have converted this second-class system into a first-class one and we have obtained two gauge invariant models. We have verified that the Poisson brackets involving the gauge invariant variables, obtained through the GU formalism, coincide with the Dirac brackets between the original second-class variables of the phase space. Finally, we have obtained two gauge invariant Lagrangians where one of them represents the Stueckelberg form.Comment: revised version. To appear in Europhysics Letter

Online trigger processing for a small-animal RPC-PET camera

A complex task for positron emission tomography (PET) cameras is the design of an appropriate coincidence-detec tion trigger system as it usually encompasses coincidences in a large number of channels and requires tight time specifications. Those requirements are even greater for a resistive plate chamber (RPC)-based detector technology since the time window specifica tion is quite small (in the order of a few hundred picoseconds) and the number of coincidence-channels can be quite large. Previous work showed that the time resolution for gamma photon pairs of a detector based on resistive plate chamber technology is under 300 ps full width at half maximum. This allows for a very tight time window for coincidence detection, with the corresponding benefits in reducing the number of random coincidences observed and, hence, the overall noise on the acquired image. In this paper, we first show experimental results of a coincidence-detection algo rithm implemented inside a Xilinx Virtex-5 field-programmable gate array for a small-animal RPC-PET camera being built.info:eu-repo/semantics/publishedVersio

First in-beam studies of a Resistive-Plate WELL gaseous multiplier

We present the results of the first in-beam studies of a medium size (10$\times$10 cm$^2$) Resistive-Plate WELL (RPWELL): a single-sided THGEM coupled to a pad anode through a resistive layer of high bulk resistivity ($\sim$10$^9 \Omega$cm). The 6.2~mm thick (excluding readout electronics) single-stage detector was studied with 150~GeV muons and pions. Signals were recorded from 1$\times$1 cm$^2$ square copper pads with APV25-SRS readout electronics. The single-element detector was operated in Ne\(5% $\mathrm{CH_{4}}$) at a gas gain of a few times 10$^4$, reaching 99$\%$ detection efficiency at average pad multiplicity of $\sim$1.2. Operation at particle fluxes up to $\sim$10$^4$ Hz/cm$^2$ resulted in $\sim$23$\%$ gain drop leading to $\sim$5$\%$ efficiency loss. The striking feature was the discharge-free operation, also in intense pion beams. These results pave the way towards robust, efficient large-scale detectors for applications requiring economic solutions at moderate spatial and energy resolutions.Comment: Accepted by JINS

Pressure dependence of Raman modes in double wall carbon nanotubes filled with α-Fe.

The preparation of highly anisotropic one-dimensional (1D) structures confined into carbon nanotubes (CNTs) in general is a key objective in CNTs research. In this work, the capillary effect was used to fill double wall carbon nanotubes with iron. The samples are characterized by Mössbauer and Raman spectroscopy, transmission electron microscopy, scanning area electron diffraction, and magnetization. In order to investigate their structural stability and compare it with that of single wall carbon nanotubes (SWNTs), elucidating the differences induced by the inner-outer tube interaction, unpolarized Raman spectra of tangential modes of double wall carbon nanotubes (DWNTs) filled with 1D nanocrystallin α-Fe excited with 514 nm were studied at room temperature and elevated pressure. Up to 16 GPa we find a pressure coefficient for the internal tube of 4.3 cm−1 GPa−1 and for the external tube of 5.5 cm−1 GPa−1. In addition, the tangential band of the external and internal tubes broadens and decreases in amplitude. All findings lead to the conclusion that the outer tube acts as a protection shield for the inner tubes (at least up 16 GPa). Structural phase transitions were not observed in this range of pressure

Late-Time Behavior of Stellar Collapse and Explosions: I. Linearized Perturbations

Problem with the figures should be corrected. Apparently a broken uuencoder was the cause.Comment: 16pp, RevTex, 6 figures (included), NSF-ITP-93-8

Development of tools to support the production planning in a textile company

Technologies are constantly evolving and so with advances in industry 4.0, its intelligent technologies with production planning and control (PPC) give rise to a smart PPC. Nowadays, one of the fundamental systems in a company is the ERP, since it allows the integration of various information from the different areas belonging to an organization, which allows access to data in real time, among other things. Through a work carried out in a textile company, it was noticeable the need to develop a tool to support its installed ERP system and the respective data control. Thus, it is noted that PPC systems, which include the integration of all areas of a company, must be adapted to its environment, work method and characteristics. With the application of this tool, it was possible to perceive an increase in efficiency and speed in obtaining the desired results, being that it is still under development and could evolve even more.FCT - Fundação para a Ciência e a Tecnologia(UIDB/00319/2020

A Comparison between the Presence and Absence of Regulation in the Spanish Electricity Market

There is an important gap in the literature on the promotion of competition in electricity markets in what pertains to the analysis of two different streams: the absence and presence of regulation. Accordingly, the main objective of this study is to analyze the interactions among market power indexes, marginal costs, and bidding strategies in the two mentioned scenarios, for comparative purposes. The methodology used is based on panel cointegration methods. The results point to the significant inclusion of different bidding strategies in the retail market: (i) fuel prices exercise a differential impact on the power plants’ marginal costs, (ii) the marginal costs have a significantly positive effect on quantity sold and on net quantity, and (iii) the market power measures under regulation have a significantly positive long-term impact on the quantity sold and a negative impact on net quantity supplied in wholesale market. Although there is some literature on this issue, the main novelty of this article is the discussion of the regulatory implications that could have been adopted in order to control and mitigate the market power, to encourage new investments in new technologies, and to recover sunk costs with the transition to a competitive market