Factors Affecting the Performance of Broilers

The efficiency of broiler production has increased greatly in recent years and can be attributed to advancements in the areas of breeding, management, nutrition, and disease control. No single factor in any one of these areas can be said to account for the major share of this increased efficiency but rather it is the combination of a large number of factors such as breeding techniques, and breed improvement, of improved management practices, and of advances in nutrition and disease control. The optimum combination of conditions or factors for broiler production is seldom, if ever, realized. Information which might have been considered adequate at the time it was obtained may soon become out-dated. To continue to increase the efficiency of broiler production, frequent re-evaluation of management factors must be made and new practices developed. It was with these thoughts in mind that the series of experiments herein reported were designed and conducted

Trees and grass contribution to soil organic carbon in agroforestry systems.

Agroforestry systems have the potential to enhance carbon (C) sequestration in soil compared with treeless (agricultural) systems (Montagnini & Nair, 2004). When one type of vegetation is replaced with another, stable isotope contents (?13 C) values can be used to identify soil organic carbon (SOC) derived from residues in the native vegetation and the new vegetation based on discrimination between C3 and C4 plants. The present study aimed to assessing the impact of difference land-use systems on C3 and C4 contribution to SOC. The experimental area is located inside the Cerrado biome. Soil samples were taken from six different land-use sites: (i) native local forest; (ii) Eucalyptus forest (EF) established in 1985 (OEC); (iii) EF established in 2004 (NEC); (iv) pasture of B. decumbens; (v) Agroforestry System (AF) established on 1994 (OAF); and (vi) AF established on 2004 (NAF). The establishment on AF was placed first with the eucalyptus planted and rice (Oryza sativa), soybean (Glycine max) and braquiaria grass (B. Brizantha cv. Marandu) in between trees rows. Soil was collected from four depths (0-10; 10-20; 20-50 and 50-100 cm). For stable C isotope analysis, whole soil was analyzed mass spectrometer. The percentage of SOC derived from the Brachiaria ssp., a C4 plant, or from the eucalyptus or native forest, a C3 plant, was estimated based on the equations: % C4-derived SOC = (?- ?T)/(?G- ?T) x 100 (1); % C3-derived SOC = 100 - % C4-derived SOC (2) Based on the equations 1 and 2 were calculated the contributions of each C3 and C4 species in SOC C-derived, as follows: C3-devived SOC (Mg ha-1) = (% C3-derived SOC) x (SOC content, Mg ha-1) (3); C4-derived SOC (Mg ha-1) = (% C4-derived SOC) x (SOC content, Mg ha-1) (4). A complete randomized design was used with Tukey?s studentized. Statistical differences were considered significant at p <0.05

Interhalogens as Oxidimetric Titrants: Part VIII* - Semimicro Determination of Some Thiourea Complexes Using Iodine Monochloride

599-60

Biexciton recombination rates in self-assembled quantum dots

The radiative recombination rates of interacting electron-hole pairs in a quantum dot are strongly affected by quantum correlations among electrons and holes in the dot. Recent measurements of the biexciton recombination rate in single self-assembled quantum dots have found values spanning from two times the single exciton recombination rate to values well below the exciton decay rate. In this paper, a Feynman path-integral formulation is developed to calculate recombination rates including thermal and many-body effects. Using real-space Monte Carlo integration, the path-integral expressions for realistic three-dimensional models of InGaAs/GaAs, CdSe/ZnSe, and InP/InGaP dots are evaluated, including anisotropic effective masses. Depending on size, radiative rates of typical dots lie in the regime between strong and intermediate confinement. The results compare favorably to recent experiments and calculations on related dot systems. Configuration interaction calculations using uncorrelated basis sets are found to be severely limited in calculating decay rates.Comment: 11 pages, 4 figure

Thermal Decomposition Studies: Part VII* - Kinetics of Depyridination of Pyridine-thiocyanato Complexes of Mn (II), Ni (II), Cu (II) & Zn (II)

402-40

Interhalogens as Oxidimetric Titrants: Part VI* - Oxidimetric Determinations with Bromine Monochloride

115-11

Cluster-based feedback control of turbulent post-stall separated flows

We propose a novel model-free self-learning cluster-based control strategy for general nonlinear feedback flow control technique, benchmarked for high-fidelity simulations of post-stall separated flows over an airfoil. The present approach partitions the flow trajectories (force measurements) into clusters, which correspond to characteristic coarse-grained phases in a low-dimensional feature space. A feedback control law is then sought for each cluster state through iterative evaluation and downhill simplex search to minimize power consumption in flight. Unsupervised clustering of the flow trajectories for in-situ learning and optimization of coarse-grained control laws are implemented in an automated manner as key enablers. Re-routing the flow trajectories, the optimized control laws shift the cluster populations to the aerodynamically favorable states. Utilizing limited number of sensor measurements for both clustering and optimization, these feedback laws were determined in only $O(10)$ iterations. The objective of the present work is not necessarily to suppress flow separation but to minimize the desired cost function to achieve enhanced aerodynamic performance. The present control approach is applied to the control of two and three-dimensional separated flows over a NACA 0012 airfoil with large-eddy simulations at an angle of attack of $9^\circ$, Reynolds number $Re = 23,000$ and free-stream Mach number $M_\infty = 0.3$. The optimized control laws effectively minimize the flight power consumption enabling the flows to reach a low-drag state. The present work aims to address the challenges associated with adaptive feedback control design for turbulent separated flows at moderate Reynolds number.Comment: 32 pages, 18 figure