3,615 research outputs found
Enzymes as Feed Additive to Aid in Responses Against Eimeria Species in Coccidia-Vaccinated Broilers Fed Corn-Soybean Meal Diets with Different Protein Levels
This research aimed to evaluate the effects of adding a combination of exogenous enzymes to starter diets varying in protein content and fed to broilers vaccinated at day of hatch with live oocysts and then challenged with mixed Eimeria spp. Five hundred four 1-d-old male Cobb-500 chickens were distributed in 72 cages. The design consisted of 12 treatments. Three anticoccidial control programs [ionophore (IO), coccidian vaccine (COV), and coccidia-vaccine + enzymes (COV + EC)] were evaluated under 3 CP levels (19, 21, and 23%), and 3 unmedicated-uninfected (UU) negative controls were included for each one of the protein levels. All chickens except those in unmedicated-uninfected negative controls were infected at 17 d of age with a mixed oral inoculum of Eimeria acervulina, Eimeria maxima, and Eimeria tenella. Live performance, lesion scores, oocyst counts, and samples for gut microflora profiles were evaluated 7 d postinfection. Ileal digestibility of amino acids (IDAA) was determined 8 d postinfection. Microbial communities (MC) were analyzed by G + C%, microbial numbers were counted by flow cytometry, and IgA concentrations were measured by ELISA. The lowest CP diets had poorer (P ≤ 0.001) BW gain and feed conversion ratio in the preinfection period. Coccidia-vaccinated broilers had lower performance than the ones fed ionophore diets during pre- and postchallenge periods. Intestinal lesion scores were affected (P ≤ 0.05) by anticoccidial control programs, but responses changed according to gut section. Feed additives or vaccination had no effect (P ≥ 0.05) on IDAA, and diets with 23% CP had the lowest (P ≤ 0.001) IDAA. Coccidial infection had no effect on MC numbers in the ileum but reduced MC numbers in ceca and suppressed ileal IgA production. The COV + EC treatment modulated MC during mixed coccidiosis infection but did not significantly improve chicken performance. Results indicated that feed enzymes may be used to modulate the gut microflora of cocci-vaccinated broiler chickens
Ehrenfest dynamics is purity non-preserving: a necessary ingredient for decoherence
We discuss the evolution of purity in mixed quantum/classical approaches to
electronic nonadiabatic dynamics in the context of the Ehrenfest model. As it
is impossible to exactly determine initial conditions for a realistic system,
we choose to work in the statistical Ehrenfest formalism that we introduced in
Ref. 1. From it, we develop a new framework to determine exactly the change in
the purity of the quantum subsystem along the evolution of a statistical
Ehrenfest system. In a simple case, we verify how and to which extent Ehrenfest
statistical dynamics makes a system with more than one classical trajectory and
an initial quantum pure state become a quantum mixed one. We prove this
numerically showing how the evolution of purity depends on time, on the
dimension of the quantum state space , and on the number of classical
trajectories of the initial distribution. The results in this work open new
perspectives for studying decoherence with Ehrenfest dynamics.Comment: Revtex 4-1, 14 pages, 2 figures. Final published versio
Quantum memories based on engineered dissipation
Storing quantum information for long times without disruptions is a major
requirement for most quantum information technologies. A very appealing
approach is to use self-correcting Hamiltonians, i.e. tailoring local
interactions among the qubits such that when the system is weakly coupled to a
cold bath the thermalization process takes a long time. Here we propose an
alternative but more powerful approach in which the coupling to a bath is
engineered, so that dissipation protects the encoded qubit against more general
kinds of errors. We show that the method can be implemented locally in four
dimensional lattice geometries by means of a toric code, and propose a simple
2D set-up for proof of principle experiments.Comment: 6 +8 pages, 4 figures, Includes minor corrections updated references
and aknowledgement
Towards a definition of quantum integrability
We briefly review the most relevant aspects of complete integrability for
classical systems and identify those aspects which should be present in a
definition of quantum integrability.
We show that a naive extension of classical concepts to the quantum framework
would not work because all infinite dimensional Hilbert spaces are unitarily
isomorphic and, as a consequence, it would not be easy to define degrees of
freedom. We argue that a geometrical formulation of quantum mechanics might
provide a way out.Comment: 37 pages, AmsLatex, 1 figur
NANoREG evaluation: Fish acute exposure to TiO2, ZnO and SiO2.
The Laboratory of Ecotoxicology and Biosafety from Embrapa Environment participated in nanomaterial ecotoxicity evaluation inside the NANOoREG approach. Toxicity test were performed with Brachydanio rerio (zebrafish), according to Nanoreg SOPFish, Acute Toxicity Test for NANoREG core nanomaterials, Version 1 (Souza, Freitas and Zucolotto, 2015). Fish were maintained in reconstituted water (pH 7±0.5, conductivity 600±50 mS/cm, 28oC ± 1oC), under a 14/10h light /dark cycle, they were not feed during the test. The Nanoreg material tested were ZnO (2883578/JRCNM01101a/99070), TiO2 (2883578/ JRCNM01001a/990407) and SiO2 (PRA02/7625, 7627, 7629, 7630). A nanomaterial stock suspension of 1 g/L in ultrapure water was sonicated during 15 min, 400 W/L, 20 kHz before preparing the test suspension. All materials were tested at a maximum concentration of 100 mg/L with and without NOM Suwanee River (10 mg/L). Fish were exposed in a proportion of 1.0 g fish/L during 96 hours in a static system with constant aeration. Animals wereevaluated concerning mortality and behavior abnormalities (loss of equilibrium, swimming behavior, respiratory function, etc.). There was no mortality or abnormal behavior. So, the estimated LC50 is greater than 100 mg/L to all nanomaterials tested. Results obtained by these SOP were useful to provide information for regulatory decisions
Assessing the Hierarchical Hamiltonian Splitting Integrator for Collisionless N-body Simulations
The N-body problem has become one of the hottest topics in the fields of
computational dynamics and cosmology. The large dynamical range in some
astrophysical problems led to the use of adaptive time steps to integrate
particle trajectories, however, the search of optimal strategies is still
challenging. We quantify the performance of the hierarchical time step
integrator Hamiltonian Splitting (HamSp) for collisionless multistep
simulations. We compare with the constant step Leap-Frog (LeapF) integrator and
the adaptive one (AKDK). Additionally, we explore the impact of different time
step assigning functions. There is a computational overhead in HamSp however
there are two interesting advantages: choosing a convenient time-step function
may compensate and even turn around the efficiency compared with AKDK. We test
both reversibility and time symmetry. The symmetrized nature of the HamSp
integration is able to provide time-reversible integration for medium time
scales and overall deliver better energy conservation for long integration
times, and the linear and angular momentum are preserved at machine precision.
We address the impact of using different integrators in astrophysical systems.
We found that in most situations both AKDK and HamSp are able to correctly
simulate the problems. We conclude that HamSp is an attractive and competitive
alternative to AKDK, with, in some cases, faster and with better energy and
momentum conservation. The use of recently discussed Bridge splitting
techniques with HamSp may allow to reach considerably high efficiency.Comment: 13 pages, 16 figure
Proton and Helium Spectra from the CREAM-III Flight
Primary cosmic-ray elemental spectra have been measured with the
balloon-borne Cosmic Ray Energetics And Mass (CREAM) experiment since 2004. The
third CREAM payload (CREAM-III) flew for 29 days during the 2007-2008 Antarctic
season. Energies of incident particles above 1 TeV are measured with a
calorimeter. Individual elements are clearly separated with a charge resolution
of ~0.12 e (in charge units) and ~0.14 e for protons and helium nuclei,
respectively, using two layers of silicon charge detectors. The measured proton
and helium energy spectra at the top of the atmosphere are harder than other
existing measurements at a few tens of GeV. The relative abundance of protons
to helium nuclei is 9.53+-0.03 for the range of 1 TeV/n to 63 TeV/n. The ratio
is considerably smaller than other measurements at a few tens of GeV/n. The
spectra become softer above ~20 TeV. However, our statistical uncertainties are
large at these energies and more data are needed
Foundations Performance of Large Diameter Tanks
The paper presents a detailed case history of foundation performance of six 60-m diameter, 15-m high, floating roof fuel oil tanks and six 96.8-m diameter, 20-m high, fixed roof process water tanks built for a large power plant. Tank walls were supported by concrete ringwall footings. General subsurface conditions at the site are discussed, along with proposed site grading and the rationale for tank foundation selection. Because vibro-replacement improvement of site soils had been used beneath settlement-sensitive structures, there was skepticism regarding the decision to support the tanks on unimproved soils. To allay doubts about the adequacy of tank foundation performance, a staged hydrotesting procedure and an extensive settlement monitoring program were developed and implemented. The excellent tank hydrotesting results demonstrated that ground improvement was not needed due to the more settlement-tolerant nature of the tanks
A recursive kinematic random forest and alpha beta filter classifier for 2D radar tracks
In this work, we show that by using a recursive random forest together with an alpha beta filter classifier it is possible to classify radar tracks from the tracks’ kinematic data. The kinematic data is from a 2D scanning radar without Doppler or height information. We use random forest as this classifier implicit handles the uncertainty in the position measurements. As stationary targets can have an apparently high speed because of the measurement uncertainty, we use an alpha beta filter classifier to classify stationary targets from moving targets. We show an overall classification rate from simulated data at 82.6 % and from real world data 79.7 %. Additional to the confusion matrix we also show recordings of real world data
Edge Detection in SAR images using phase stretch transform
In this work a novel approach to edge detection on Synthetic Aperture Radar (SAR) images is introduced. The proposed method uses an optics inspired transform which emulates the diffraction of an image through a medium with nonlinear dispersive properties. The experimental results show that the output of the introduced Phase Stretch Transform (PST) in conjunction with further morphological operations can be effectively used for image edge detection
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