Short communication: Effects of the addition of a marigold extract to diets fed to channel catfish (Ictalurus punctatus) on growth parameters

The expansion of aquaculture in the last 10 years has made it an important source of protein worldwide. However, increased production, and the culture intensification it carries, results in higher risk of infectious disease due to poor water quality and high stocking densities. ... Marigold (Tagetes erecta L.) is a plant native to Mexico whose flowers accumulate carotenoids. Natural carotenoids extracted from marigold have been used in aquaculture to help in the survival of fish juvenile stages by strengthening their immunological system, thus reducing mortality rates. The effect of carotenoids in fish health may exert a positive effect on fish growth indices; however, these effects on growth parameters have not been studied in channel catfish (Ictalurus punctatus), which is the most cultured fish species in north-eastern Mexico, and one of the most cultured on the southern United States. Consequently, the aim of this study was to investigate if there were significant differences in growth among channel catfish juveniles when fed diets containing various carotenoid doses from a natural source

Short communication: Effects of the addition of a marigold extract to diets fed to channel catfish (Ictalurus punctatus) on growth parameters

The expansion of aquaculture in the last 10 years has made it an important source of protein worldwide. However, increased production, and the culture intensification it carries, results in higher risk of infectious disease due to poor water quality and high stocking densities. ... Marigold (Tagetes erecta L.) is a plant native to Mexico whose flowers accumulate carotenoids. Natural carotenoids extracted from marigold have been used in aquaculture to help in the survival of fish juvenile stages by strengthening their immunological system, thus reducing mortality rates. The effect of carotenoids in fish health may exert a positive effect on fish growth indices; however, these effects on growth parameters have not been studied in channel catfish (Ictalurus punctatus), which is the most cultured fish species in north-eastern Mexico, and one of the most cultured on the southern United States. Consequently, the aim of this study was to investigate if there were significant differences in growth among channel catfish juveniles when fed diets containing various carotenoid doses from a natural source

UNA NOTA SOBRE POLINOMIOS DE GEGENBAUER

The main objective of this work is to study some properties which satisfy differential properties of the Gegenbauer orthogonal polynomials fP(l)n (x)g with n 2 N and l > 1 2 real, as the differential equation, Rodrigues formula, norm, derivative of order one. Furthermore, we show some algebraic properties such as explicit expression, principal coefficient, recurrence formula three terms and the Christoffel-Darboux formula.El objetivo principal de este trabajo es estudiar algunas propiedades diferenciales que satisfacen los polinomios ortogonalesde Gegenbauer  como la ecuación diferencial, formula de Rodrigues, norma, derivada de orden uno. Además, mostraremos algunas propiedades algebraicas tales como: expresión explicita, coeficiente principal, fórmula de recurrencia a tres términos y la fórmula de Christoffel-Darboux.  

Response of different sowing densities on agronomic parameters in the cultivation of mejen corn in Tabasco, Mexico

ABSTRACT Objective: To evaluate the response of planting densities on agronomic parameters in native Mejen maize from the State of Tabasco, Mexico. Design/methodology/approach: A randomized complete block design with four repetitions was used, where the treatments were: T1: 0.25 m between plants and two seeds per blow (80,000 plants ha-1), T2: 0.50 m between plants and three seeds per blow. blow (60,000 plants ha-1), T3: 0.75 m between plants and four seeds per blow (53,333 plants ha-1) and (T4: 1 m between plants and five seeds per blow (50,000 plants ha-1) The variables were: height of plant without male flower (APSFM, cm), of ear (AM, cm), dry biomass of plant, bracts and rachis (ton ha-1), number of bracts, rows per ear , grain per row and grain per ear, and grain yield (GY, ton ha-1). Results: It was shown that the morphological response of the plants, ears and GY was influenced by the planting densities. The treatment of 80,000 plants ha-1 expressed a GY of 4.75 ton ha-1 higher than the regional average of 1.94 t ha-1 in traditional systems in Tabasco. Limitations on study/implications: The native maize architecture allows the use of high densities to increase productivity. Findings/conclusions: It was shown that despite obtaining a lower number of grains per ear in the treatments with greater planting distances, this is compensated by the higher number of plants per row by obtaining higher grain yields. Keywords: ear, bracts, rachis, grain yield, rows.Objective: To evaluate the response of sowing densities on agronomic parameters in the native mejen corn. Design/Methodology/Approach: A randomized complete block design with four repetitions was used for the treatments: T1 (0.25 m between plants and two seeds per hole (80,000 plants ha-1)), T2 (0.50 m between plants and three seeds per hole (60,000 plants ha-1)), T3 (0.75 m between plants and four seeds per hole (53,333 plants ha-1)), and T4 (1 m between plants and five seeds per hole (50,000 plants ha-1)). The following variables were determined: plant height without male flower (PHWMF, cm), ear size (ES, cm), plant, bracts, and rachis dry biomass (t ha-1); number of bracts, rows per ear, grain per row, grains per ear, and grain yield (GY, t ha-1). Results: Sowing densities influence the morphological response of plants, ears, and GY. The treatment with 80,000 plants ha-1 recorded a GY of 4.75 t ha-1 in traditional systems in Tabasco —greater than the regional average of 1.94 t ha-1. Study Limitations/Implications: The architecture of native corn allows an increase in productivity, as a result of the use of high densities. Findings/Conclusions: Although treatments with greater sowing distances obtained a lower number of grains per ear, this phenomenon is compensated by the greater number of plants per row that leads to higher grain yields

Control por bloques adaptativo por modelo de referencia In silico para pacientes con diabetes tipo 1

En este trabajo se presenta un controlador adaptativo por modelo de referencia basado en la transformación del modelo no lineal a la forma controlable por bloques (MRAC-NBC) y unilateral. El controlador está formado por dos lazos, uno donde se ajusta el seguimiento del modelo del paciente y el otro donde se propone la glucosa de seguimiento para el paciente virtual. Las ganancias del NBC son ajustadas de forma heurística mediante la comparación de los estados del modelo de referencia con respecto a la estimación de los estados del paciente. En el lazo del modelo de referencia la dinámica se obtiene mediante el modelo de Bergman con un conjunto medio de parámetros, mientras que el lazo de paciente utiliza el mismo modelo, pero parametrizado de forma diferente. El MRAC-NBC respecto del NBC es capaz de conducir la glucemia del paciente a una glucosa objetivo independientemente de la variabilidad interpaciente y de las ingestas, aumentando el Target In Range en más del 18 %

Search for low-mass WIMPs in a 0.6 kg day exposure of the DAMIC experiment at SNOLAB

We present results of a dark matter search performed with a 0.6 kg day exposure of the DAMIC experiment at the SNOLAB underground laboratory. We measure the energy spectrum of ionization events in the bulk silicon of charge-coupled devices down to a signal of 60 eV electron equivalent. The data are consistent with radiogenic backgrounds, and constraints on the spin-independent WIMP-nucleon elastic-scattering cross section are accordingly placed. A region of parameter space relevant to the potential signal from the CDMS-II Si experiment is excluded using the same target for the first time. This result obtained with a limited exposure demonstrates the potential to explore the low-mass WIMP region (<10 GeV/$c^{2}$) of the upcoming DAMIC100, a 100 g detector currently being installed in SNOLAB.Comment: 11 pages, 11 figure

Gaia Early Data Release 3:Modelling and calibration of Gaia's point and line spread functions

Context: The unprecedented astrometric precision of the Gaia mission relies on accurate estimates of the locations of sources in the Gaia data stream. This is ultimately performed by point spread function (PSF) fitting, which in turn requires an accurate reconstruction of the PSF. Gaia Early Data Release 3 (EDR3) will, for the first time, use a PSF calibration that models several of the strongest dependences, leading to signficantly reduced systematic errors. Aims: We describe the PSF model and calibration pipeline implemented for Gaia EDR3, including an analysis of the calibration results over the 34 months of data. We include a discussion of the limitations of the current pipeline and directions for future releases. This will be of use both to users of Gaia data and as a reference for other precision astrometry missions. Methods: We develop models of the 1D line spread function (LSF) and 2D PSF profiles based on a linear combination of basis components. We fit the models to selected primary sources in independent time ranges, using simple parameterisations for the colour and other dependences. Variation in time is smoothed by merging the independent calibrations in a square root information filter, with resets at certain mission events that induce a discontinuous change in the PSF. Results: The PSF calibration shows strong time and colour dependences that accurately reproduce the varying state of the Gaia astrometric instrument. Analysis of the residuals reveals both the performance and the limitations of the current models and calibration pipeline, and indicates the directions for future development. Conclusions: The PSF modelling and calibration carried out for Gaia EDR3 represents a major step forwards in the data processing and will lead to reduced systematic errors in the core mission data products. Further significant improvements are expected in the future data releases.Comment: Accepted by A&A for inclusion in Gaia EDR3 special issu