Joel Perez

Simple Summary: The present study evaluates the effects of two dietary supplements (guanidinoacetic acid [GAA] and zilpaterol hydrochloride [ZLH]) on the productive performance of fattening lambs over a 60-day period. The inclusion of these additives did not result in significant differences in the parameters studied. However, serum glucose and creatinine levels in the GAA group were higher than those in the control group. These findings suggest that further research is needed to determine the optimal dosage and duration of GAA supplementation to enhance lamb growth and meat production. Abstract: This study evaluated the effects of dietary supplementation with guanidinoacetic acid (GAA) and zilpaterol hydrochloride (ZLH) on productive performance, carcass traits, and blood chemistry in non-castrated male lambs over 60 days. Twenty-four Pelibuey × Dorper crossbred lambs (16.3 ± 2.7 kg) were adapted to housing and diet for 14 days before being randomly assigned to one of three treatments: (1) Control: total mixed ration (TMR) without additives; (2) GAA: TMR with 0.2% GAA; and (3) ZLH: TMR with 6 mg/kg dry matter (DM) of ZLH for the last 30 days. No significant differences were observed in productive performance or carcass traits among treatments. However, lambs fed GAA showed higher serum glucose and creatinine levels than the control group (p < 0.05), suggesting a potential effect on energy metabolism. ZLH supplementation had no measurable impact on the parameters evaluated. These findings indicate that while GAA may influence certain metabolic indicators, further research with extended feeding periods or varying dosages is needed to clarify its effects on growth and carcass characteristics in lambs.

The objective of this research is to conduct a comparative analysis of the two models of growth and development that were applied in Peru over the past six decades (1961-2021). The objective is to conduct a comparative analysis of the Import Substitution Model (ISM) and the Liberal Model (LM), to determine which of these models has demonstrated superior performance in terms of economic growth and social welfare for the country. In this instance, the documentary and systematic review of the material obtained from both physical and virtual libraries was employed as a method. Consequently, a variety of economic indicators have been examined, including the primary indicator of economic growth, gross domestic product (GDP), to account for the effects of inflation and ensure the accuracy of the data. Furthermore, the principal social indicators have been examined and contrasted to gauge the nation's social well-being. The findings of the study demonstrate that the ML has demonstrably outstripped the MSI in terms of economic growth and the enhancement of social welfare for Peruvian society over the past three decades. However, it would be erroneous to assume that this model has entirely resolved the country's economic and social challenges.

The construct of the self is important in the domain of memory research. Recent work has shown that person memory is influenced by similarity of social targets to the self. The current experiments investigate self-similarity as defined by traits and political ideology to better understand how memory for social targets is organised. Across three experiments, participants formed positive or negative impressions based on each target’s picture, a trait-implying behavior (Experiments 1 & 2), and/or political ideology (conservative/liberal label in Experiment 2; political-ideological belief statements in Experiment 3) followed by a memory test. Results showed a self-similarity effect dependent on valence in Experiment 1, but not in Experiments 2 or 3 when participants processed ideological information associated with targets. These results suggest that self-similarity has an effect on memory for social targets, but that ideological information disrupts self-focused processing of others, suggesting that ideological information also has a powerful influence on what people remember about others (i.e. social targets).

Standard adaptive control is the preferred approach for stabilization and synchronization of chaotic systems when the structure of such systems is a priori known but the parameters are unknown. However, in the presence of unmodeled dynamics and/or disturbance, this approach is not effective anymore due to the drift of the parameter estimations, which eventually causes the instability of the closed-loop system. In this paper, a robustifying term, which consists of a saturation function, is used to avoid this problem. The robustifying term is added to the adaptive control law. Consequently, the learning law is also modified. The boundedness of the states and the parameter estimations is rigorously and thoroughly proven by means of Lyapunov like analysis based on Barbalat’s lemma. On these new conditions, the convergence to zero cannot be achieved due to the presence of unmodeled dynamics and/or disturbance. However, it is still possible to guarantee the asymptotic convergence to a bounded zone around zero. The width of this zone can be adjusted by the designer. The performance of this robust approach is verified by numerical simulations. Although, for simplicity, this strategy is only applied to the stabilization and synchronization of Zhang system, the procedure can easily be generalized to a broad class of chaotic systems.

La agroecología tiene como objetivo el conocimiento de los elementos y procesos claves en el funcionamiento de los agrosistemas, para su eficaz gestión en armonía con el ambiente. La protección vegetal ha sido enfocada tradicionalmente, bajo el concepto de lucha y control, utilizando arsenales químicos o biológicos y, en estos momentos, biotecnológicos. La aplicación de criterios ecológicos en protección vegetal ha permitido desarrollar procesos como la biofumigación, fundamentada en la utilización de los gases resultantes de la biodescomposición de la materia orgánica para el manejo de organismos patógenos de los vegetales. Es de esperar que el futuro de la agricultura muestre una mayor preocupación por el ambiente, la conservación de los recursos naturales, la salud de las personas y se destaque su contribución a la reducción de la pobreza, así como su aportación al desarrollo de los agrocombustibles.