Impact of bacteria and yeast with probiotic properties on performance, digestibility, health status and gut environment of growing pigs in Vietnam

This thesis aimed to evaluate the effects of six lactic acid bacteria (LAB) strains and Bacillus subtilis H4, Saccharomyces boulardii Sb, and a microbial enzyme mixture, supplemented to basal diets on the performance, diet digestibility, health status, and gut environment of growing pigs under Vietnamese conditions. The results showed that three different 3-strain-LAB complexes, comprising combinations of Enterococcus faecium 6H2, Lactobacillus acidophilus C3, Pediococcus pentosaceus D7, L. plantarum 1K8 and L. plantarum 3K2 improved performance, digestibility, health status and gut environment of the LAB-supplemented piglets in the first two weeks post-weaning (Per I), but not in the following 3 weeks (Per II). Adding an LAB strain (L. fermentum NC1) alone or combined with the Bacillus, or combined with a Bacillus and yeast complex, to a 3-strain-LAB complex showed improvements in the performance, diet digestibility, health status and gut environment of the probiotics-supplemented piglets in both Per I and II. The inclusion of Bacillus resulted in higher nutrient digestibility, and the addition of Saccharomyces showed improvements in the scouring scores of the piglets. Supplementation with either a microbial enzyme mixture alone or a combination of a 3-strain-LAB complex and yeast in a weaner diet improved the performance and diet digestibility in piglets in Per I. In Per II, no changes in performance or digestibility were found in enzymes-fed piglets, while improved performance and diet digestibility were obtained in piglets fed the LAB-yeast diet. There was lack of response of piglets to this enzyme mixture when these enzymes were supplemented to the diet that contained the complex of LAB and yeast in both Per I and II. Dietary supplementation with the combination of Bacillus, Saccharomyces and 4-strain-LAB complex had positive effects on performance and digestibility in grower pigs, but not in finisher pigs, while supplementation with the Bacillus alone or combined with Saccharomyces did not affect the performance and digestibility in grower and finisher pigs. The results of these studies suggest that combinations of suitable strains of Bacillus, Saccharomyces and LAB can be used as an alternative to antibiotic feed additives in pig production under the conditions of Vietnam

Viscosity solutions to parabolic complex Monge-Amp\`ere equations

In this paper, we study the Cauchy-Dirichlet problem for Parabolic complex Monge-Amp\`ere equations on a strongly pseudoconvex domain by the viscosity method. We extend the results in [EGZ15b] on the existence of solution and the convergence at infinity. We also establish the H\"older regularity of the solutions when the Cauchy-Dirichlet data are H\"older continuous.Comment: 35 pages. arXiv admin note: text overlap with arXiv:1407.2494 by other author

Quantum Gauss Jordan Elimination

In this paper we construct the Quantum Gau\ss Jordan Elimination (QGJE) Algorithm and estimate the complexity time of computation of Reduced Row Echelon Form (RREF) of an $N\times N$ matrix using QGJE procedure. The main theorem asserts that QGJE has computation time of order $2^{N/2}$

Path Tracking Controller of Quadruped Robot for Obstacle Avoidance Using Potential Functions Method

This paper proposes a tracking controller for obstacle avoidance of a quadruped robot using potential functions method. The followings are done for this task. At first, a ceiling-mounted camera system is installed for image processing. The goal point and obstacles are separated and recognized by a color recognition method. Second, a path planning algorithm using potential functions method is proposed to generate the path to avoid obstacles and to plan a path for the quadruped robot to reach from start point to goal point. Third, a quadruped robot is chosen as the mobile platform for this study and the kinematic model for the robot is presented. Fourth, a tracking controller is designed for the quadruped robot to track the trajectory based on the backstepping method using Lyapunov function. Finally, the simulation results are presented to show the effectiveness of the proposed trajectory planning algorithm and the tracking controller. [Keywords— Path tracking; back stepping; obstacles avoidance; potential functions; quadruped robot]

Occurrence and dissipation of the antibiotics sulfamethoxazole, sulfadiazine, trimethoprim, and enrofloxacin in the Mekong Delta, Vietnam

The Mekong Delta in Vietnam has seen a rapid development and intensification of aquaculture in the last decades, with a corresponding widespread use of antibiotics. This study provides information on current antibiotic use in freshwater aquaculture, as well as on resulting antibiotic concentrations in the aquatic environment of the Mekong Delta. Two major production steps, fish hatcheries and mature fish cultivation, were surveyed (50 fish farm interviews) for antibiotic use. Different water sources, including surface water, groundwater and piped water (164 water samples) were systematically screened for antibiotic residues. To better understand antibiotic fate under tropical conditions, the dissipation behavior of selected antibiotics in the aquatic environment was investigated for the first time in mesocosm experiments. None of the investigated antibiotics were detected in groundwater and piped water samples. Surface water, which is still often used for drinking and domestic purposes by local populations, contained median concentrations of 21 ng L-1 sulfamethoxazole (SMX), 4 ng L-1 sulfadiazine (SDZ), 17 ng L-1 trimethoprim (TRIM), and 12 ng L-1 enrofloxacin (ENRO). These concentrations were lower than the predicted no effect concentrations (PNECs) and minimum inhibitory concentrations (MICs), suggesting limited antibiotic-related risk to aquatic ecosystems in the monitored systems. The dissipation half-lives of the studied antibiotics ranged from <1 to 44 days, depending on the availability of sunlight and sediment. Among the studied antibiotics TRIM was the most persistent in water systems. TRIM was not susceptible to photodegradation, while the dissipation of ENRO and SDZ was influenced by photolysis. The recorded dissipation models gave good predictions of the occurrence and concentrations of TRIM, ENRO and SDZ in surface water. In summary, the currently measured concentrations of the investigated antibiotics are unlikely to cause immediate risks to the aquatic environment, yet the persistence of these antibiotics is of concern and might lead to chronic exposure of aquatic organisms as well as humans