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91 results on '"Figueroa, J. L."'

7. Digestible lysine levels in low-protein diets supplemented with synthetic amino acids for nursery, growing, and finishing barrows

Author

Figueroa, J. L., Estrada, J., Zamora, V., Cordero, J. L., Sánchez-Torres, M. T., Nieto, R., and Copado, J. M. F.

Subjects
Lysine levels, Plasma urea nitrogen concentration, Pigs, Low-protein diets
Abstract

peer-reviewed article To investigate the effect of lysine level in low-protein diets (LPD) an experiment was conducted with 36 barrows fed 174, 140 and 118 g/kg of crude protein (CP), and three digestible lysine levels. Low-protein diets were supplemented with crystalline amino acids (AA) to the same concentration as in the standard CP diet. Growth performance, carcass characteristics and plasma urea nitrogen concentration were evaluated. In nursery pigs, the addition of lysine to LPD quadratically increased backfat thickness (BF; P < 0.01), longissimus muscle area (LMA; P < 0.001), and lean meat percentage (LMP; P < 0.05). In the growing phase, reducing dietary protein decreased average daily gain (ADG; P < 0.09), final body weight (BW; P < 0.09), fat free lean gain (FFLG; P < 0.09), and LMA (P < 0.038); and increased BF (P < 0.05). Addition of lysine to LPD quadratically increased ADG (P < 0.01), average daily feed intake (ADFI; P < 0.05), final BW (P < 0.006), and FFLG (P < 0.002). In the finishing period, pigs fed LPD had lower ADFI (P < 0.03) and feed:gain ratio (FGR; P < 0.003). Addition of lysine to LPD linearly increased BF (P < 0.04), and quadratically increased ADFI (P < 0.02), FGR (P < 0.009), BF (P < 0.08), and LMA (P < 0.08). The plasma urea nitrogen concentration was reduced (P < 0.05) in all phases in pigs fed LPD. Lysine requirement for fattening barrows fed LPD may be higher than the recommended concentration for standard CP diets.

Published
2012

8. Physico-chemical water parameters variation in the floating cages of snappers (Lutjanus peru and L. guttatus) farmed in tropical sea

Author

Vargas-Machuca, S. C., Ponce-Palafox, J. T., Arredondo-Figueroa, J. L., Chavez-Ortiz, E. A., and Eduardo Jaime Vernon-Carter

Subjects
snappers, sea farm, Ingeniería, floating cage, Water physico-chemical parameters, Water physico, chemical parameters
Abstract

"The water column in a fish farm was sampled at three depth layers to determine large and short term changes in water quality. The overall goal of this study was to determine the variation of nutrient concentrations in the water column in open-ocean floating cages with cultures of Lutjanus peru (Pacific red snapper) and L. guttatus (spotted rose snapper). Nutrient concentration (ammonia-N, nitrite-N, nitrate-N, and phosphate) were evaluated every fifteen days in the water column at three stations (cages) and two depths; likewise, several water quality parameters were analyzed daily (water temperature, salinity, dissolved oxygen and Secchi disk). Analyses of water in general showed that no significant differences existed between the monthly concentration of nutrients from the control stations and depths. Nitrate was the nutrient with the highest concentration (2.83 to 3.56 mg/L); however, these values were relatively low and normal for these waters. The results show that when working with fish densities of 2500 to 3500 fish/cage and small quantities of food (60 ton/year) no impact is made on the water column quality in the floating cages culture system."

Published
2008

9. Sistema de Adquisición de Señales SEMG para la Detección de Fatiga Muscular.

Author

Correa-Figueroa, J. L., Morales-Sánchez, E., Huerta-Ruelas, J. A., González-Barbosa, J. J., and Cárdenas-Pérez, C. R.

Abstract

This paper presents the development of a system for acquiring and processing of surface myoelectric signals or SEMG. The proposed system acquires signals SEMG skin surface using AgCl surface electrodes. The system has an amplification step and hardware filtering to streamline the processing time. Developed software for processing the Fourier transform SEMG amplified and filtered signal. Unlike other systems for acquisition of biological signals, which are developed for therapy or rehabilitation, this system is intended to be used for the control of robotic arms, so the software performs the measurement of fatigue using parameters like bleed average frequency and instantaneous power spectral density of the signal SEMG. [ABSTRACT FROM AUTHOR]

Published
2016
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10. Metaanálisis del efecto de dietas bajas en proteína y adicionada con aminoácidos sintéticos para cerdos machos castrados en finalización.

Author

González, M., Figueroa, J. L., Vaquera, H., Sánchez-Torresa, M. T., Ortega, M. E., Copado, J. M. F., and Martínez, J. A.

Abstract

Copyright of Archivos de Medicina Veterinaria is the property of Universidad Austral de Chile, Facultad de Ciencias Veterinarias and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Published
2016

31. Robust model predictive control of Wiener systems.

Author

Biagiola, S. I. and Figueroa, J. L.

Subjects
*ROBUST control, *PREDICTIVE control systems, *NONLINEAR theories, *LINEAR statistical models, *MATRIX inequalities, *UNCERTAINTY (Information theory)
Abstract

Block-oriented models (BOMs) have shown to be appealing and efficient as nonlinear representations for many applications. They are at the same time valid and simple models in a more extensive region than time-invariant linear models. In this work, Wiener models are considered. They are one of the most diffused BOMs, and their structure consists in a linear dynamics in cascade with a nonlinear static block. Particularly, the problem of control of these systems in the presence of uncertainty is treated. The proposed methodology makes use of a robust identification procedure in order to obtain a robust model to represent the uncertain system. This model is then employed to design a model predictive controller. The mathematical problem involved in the controller design is formulated in the context of the existing linear matrix inequalities (LMI) theory. The main feature of this approach is that it takes advantage of the static nature of the nonlinearity, which allows to solve the control problem by focusing only in the linear dynamics. This formulation results in a simplified design procedure, because the original nonlinear model predictive control (MPC) problem turns into a linear one. [ABSTRACT FROM AUTHOR]

Published
2011
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32. EFECTO DE LA CAL EN EL CONTROL DE GUSANOS BARRENADORES (POLYCHAETE: SPIONIDAE) EN UN CULTIVO EXPERIMENTAL DE OSTIÓN, VARIANDO EL TIEMPO DE INMERSIÓN Y LA FRECUENCIA DE APLICACIÓN.

Author

García-Ulloa, M., Gallo-García, M. C., Ponce-Palafox, J. T., and Arredondo-Figueroa, J. L.

Subjects
WORMS, OYSTER culture, BLISTERS, OYSTER shell, LIME (Minerals), EXPERIMENTS, TIME
Abstract

Copyright of Universidad & Ciencia is the property of Universidad Juarez Autonoma de Tabasco and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Published
2008

33. H ∞ control of a Wiener-type system.

Author

Biagiola, S. I., Agamennoni, O. E., and Figueroa, J. L.

Subjects
LINEAR systems, SYSTEMS theory, CAPACITORS, COMPUTER simulation, SIMULATION methods & models
Abstract

A Wiener system is a system which can be modelled as a linear dynamic followed by a static gain. The goal of this paper is to develop a robust H ∞ compensator for controlling an SISO Wiener system. The controller also takes the form of a Wiener model. The design approach consists of the approximation of the non-linear gain using a piecewise linear (PWL) function and in using a linear controller for each sector obtained from this approximation. Therefore, the general controller structure can be stated as a linear dynamic compensator in series with a PWL static gain. As an illustrative case, a neutralization pH reaction between a strong acid and a strong base in the presence of a buffer agent is dealt with. Computer simulations are developed for showing the performance of the proposed controller. [ABSTRACT FROM AUTHOR]

Published
2004
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34. The effect of Yucca schidigera liquid extract on water quality and survival of Pacific Red Snapper Lutjanus peru during acclimatization.

Author

Castillo-Vargasmachuca, S., Ponce-Palafox, J. T., Arredondo-Figueroa, J. L., García-Ulloa, M., Benítez-Valle, A., Martínez-Cárdenas, L., Puga-López, D., and Seidavi, A.

Subjects
YUCCA schidigera, PLANT extracts, PHYSIOLOGICAL effects of water quality, BOCACCIO, FISH mortality, ACCLIMATIZATION (Plants)
Abstract

Copyright of Archivos de Medicina Veterinaria is the property of Universidad Austral de Chile, Facultad de Ciencias Veterinarias and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Published
2015
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36. Adaptive Piecewise Linear Predistorters for Nonlinear Power Amplifiers With Memory.

Author

Mei Yen Cheong, Werner, S., Bruno, M. J., Figueroa, J. L., Cousseau, J. E., and Wichman, R.

Subjects
POWER amplifiers, ANALOG electronic systems, ELECTRONIC amplifiers, DIGITAL electronics, INTEGRATED circuits, COMPLEMENTARY metal oxide semiconductors, ELECTRONIC circuits, PHOTOVOLTAIC cells
Abstract

We propose novel direct and indirect learning predistorters (PDs) that employ a new baseband simplicial canonical piecewise linear (SCPWL) function. The performance of the proposed PDs is easily controlled by varying the number of segments of the SCPWL function. When comparing to polynomial-based PDs, our SCPWL-based PDs are more robust for modeling strong nonlinearities and are less sensitive to input noise. In particular, we show that noise appearing in the feedback path of an indirect learning SCPWL-PD has negligible effect on the performance while the polynomial counterpart suffers from a noise-induced coefficient bias. We consider adaptive implementations of both Hammerstein-based and memory-based SCPWL PDs; the former featuring less parameters to be identified while the latter renders more straightforward parameter identification. When deriving the PD algorithms, we avoid a separate PA identification step which allows for a true real-time, or sample-by-sample, implementation without an alternating PA and PD identification procedure. However, to arrive at efficient sample-by-sample algorithms for Hammerstein PDs we need to bypass the problem of the associated nonconvex cost function. This is done by employing a modified, linear-in-the-parameter, Wiener model whose parameters can be explicitly or implicitly used for both indirect and direct learning. Extensive simulations confirm that the proposed SCPWL PDs outperform their polynomial counterparts, especially when noise is present in the feedback path of the indirect learning structure. The same is also verified by circuit level simulations on the Freescale MRF6S23100H class-AB PA in an 802.16d WiMAX system. [ABSTRACT FROM PUBLISHER]

Published
2012
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37. Shear Wave Velocity Measurement in Centrifuge Using Bender Elements

Author

Figueroa, J. L., Zeng, X., and Fu, Lei

Abstract

Measuring soil properties during a centrifuge flight is important for the interpretation and analysis of experimental data. In recent years, progress has been made in developing devices for in-flight measurement. This paper describes the application of the bender element technique in the measurement of shear wave velocities during the flight, spinup and spin-down of a centrifuge. Three model tests were conducted on a dry sand deposit. The experimental setup, test procedures, and test results are described in detail. The shear wave velocities in horizontal and inclined planes are measured, which are used to calculate the shear moduli in the corresponding shear planes. Test results have good repeatability and agree well with both the results of resonant column tests and calculations conducted with a commonly used empirical equation. This study shows that the bender element technique has a great potential as a reliable and inexpensive method to measure an important soil property during the flight of a centrifuge.

Published
2004
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38. State Estimation in Nonlinear Processes. Application to pH Process Control

Author

Biagiola, S. I. and Figueroa, J. L.

Abstract

In the field of process engineering, there are many factors that demand the knowledge of one part of the state vector, if not the full one. Among others, the implementation of nonlinear control methods as well as monitoring of some relevant process variables can be mentioned. The purpose of this paper is to introduce a nonlinear state observer of full order (i.e., the order of the observer matches the order of the nonlinear system observed) in order to estimate all of the state variables of the process. Though the estimated states can be used for many purposes, in this work we aim at using the estimations for output reference tracking. In particular, we deal with the pH neutralization process, which is widely recognized as a difficult problem for the purpose of control. To achieve the pH control goal, a simple algorithm is proposed which lies on a stable reference error dynamics model. Finally, computer simulations are developed for showing the performance of both the nonlinear observer and the control strategy based on pH measurement. For this purpose, a neutralization reaction between a strong acid and a strong base in the presence of a buffer agent is dealt with.

Published
2002

47. Productive response of pigs to low-protein diets added synthetic amino acids and yeast culture.

Author

Reynoso, E., Cervantes, M., Figueroa, J. L., and Cuca, J. M.

Subjects
*DIARRHEA, *LOW-protein diet, *AMINO acids, *THERAPEUTICS, *DIET in disease
Abstract

The article presents two studies which aimed to determine the benefits for the productive performance and diarrhea incidence of including yeast culture into standard and low-protein diets, to which synthetic amino acids were added. In the first experiment, 64 hybrid pigs were used and distributed in a complete random block design with four treatments. The effect of adding yeast culture to standard and low-protein diets on 64 pigs was assessed in the second through a complete random block design with factorial arrangement 2 x 2 and four repetitions.

Published
2004

49. Model uncertainty estimation of a solid oxide fuel cell using a Volterra-type model.

Author

Biagiola, S. I., Schmidt, C., and Figueroa, J. L.

Subjects
*SOLID oxide fuel cells, *VOLTERRA equations, *ESTIMATION theory, *MIMO systems, *POLYNOMIALS, *SIMULATION methods & models
Abstract

The dynamic nature of solid oxide fuel cells (SOFC) shows that they can be conceived as multi-input multi-output nonlinear processes. Aiming at dynamic simulation and control, this work presents a modeling study of a SOFC stack following a gray-box modeling approach. For such purpose, a Modified Generalized Memory Polynomial (MGMP) model is identified based only on input-output data of the system. Additionally, dedicated estimation is dealt with in order to cope with the presence of possible model uncertainty. Simulation results are given to illustrate the quality of the obtained model which is compared with other modeling approaches. [ABSTRACT FROM AUTHOR]

Published
2014
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50. [Functional endoscopic evaluation of swallowing in infants with deglutition disorders].

Author

Partida-Justo I, Israel Grijalva-Otero JE, Ramírez-Figueroa JL, Sepúlveda-Vildosola AC, and Zurita-Cruz JN

Subjects
Child, Preschool, Female, Humans, Infant, Male, Predictive Value of Tests, Reproducibility of Results, Sensitivity and Specificity, Video Recording, Deglutition physiology, Deglutition Disorders diagnosis, Endoscopy methods, Fluoroscopy methods
Abstract

Background: Functional endoscopic evaluation of swallowing (FEES) is a recognized method for Deglutition Disorders (DD) in adults, with anecdotal experience in children, obtaining not conclusive results., Objective: To compare the accuracy of test FEES in infants with high suspicion of altered DD seen in a third level hospital with the gold standard Videofluoroscopic (VF)., Patients, Material and Methods: The results and findings by FEES and VF of 66 children with clinical diagnosis of DD were compared., Statistical Analysis: An estimate of the sensitivity and specificity of FEES was performed. As well as calculating positive predictive value (PPV), negative predictive value (NPV) and likelihood ratios., Results: 60 patients enrolled, 4 and FEES showed high sensitivity to identify the presence of aspiration and penetration (9 98%) and high specificity for the arrest of spillage and waste (94% and 95%). Gastroesophageal reflux to make the diagnosis of DD with FEES had a sensitivity of 80% and specificity of 84%. Spill and penetration had the highest agreement with respect to the gold standard of 0.81., Conclusions: FEES in infants diagnosed with DD had a sensitivity of 80.8% and specificity 85.3%. 0696 concordance regarding to the VFD in the diagnosis of DD, and to identify suction stroke had a kappa of 0815.

Published
2017

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