37,218 research outputs found
Intestinal Microbial Ecology of Broilers Vaccinated and Challenged With Mixed Eimeria Species, and Supplemented with Essential Oil Blends
Intestinal microbiota is an important component in the development of defense mechanisms in the gut mucosa. This project determined the dynamics of intestinal microbial communities (MC) of broilers vaccinated at first day of age with live oocysts of Eimeria species and fed diets supplemented with 2 specific essential oil (EO) blends, Crina Poultry (CP) and Crina Alternate (CA). Five treatments were analyzed: 1) unmedicated-uninfected (UU) control; 2) unmedicated-infected (UI) control; 3) vaccinated with Advent cocci-vaccine and without feed additive (COV) supplements; 4) vaccinated with Advent and supplemented with CP; and 5) vaccinated with Advent and supplemented with CA. The EO blends were added at 100 ppm to the same basal diets. Chicks were gavage-infected at 19 d of age with Eimeria acervulina, Eimeria maxima, and Eimeria tenella. Duodenal, ileal, and cecal samples were taken from 12 birds per treatment just before the infection and 7 d after the challenge, pooled in 6 samples, and frozen. Denaturing gradient gel electrophoresis was used to examine PCR-amplified fragments of the bacterial 16S ribosomal DNA variable region. Results are presented as percentages of similarity coefficients (SC). Dendrograms of amplicon patterns indicated MC differences due to intestinal location, feed additives, and cocci infection. The EO blends CP and CA did affect MC in all gut sections. The cocci-infection caused drastic MC population shifts in duodenal, ileal, and cecal sections (36.7, 55.4, and 36.2% SC, respectively). The CP-supplemented birds had higher SC between pre- and postchallenge MC in duodenal and ileal (73.3, 81.8%) than COV (66.4, 66.5%). However, COV broilers had the smallest changes in cecal MC after infection (79.5% SC). We concluded that cocci-vaccination causes small changes in intestinal MC, but challenge causes drastic shifts. The EO blend supplementation modulates MC in cocci-vaccinated broilers, avoiding drastic shifts after a mixed coccidia infection. Correlations between MC dynamics and host responses are discussed
Baseline report on the evaluation of Familias en Acción
This report describes the survey that was carried out in 122 communities in rural Colombia by the consortium formed by the Institute for Fiscal Studies, Econometria and SEI as the baseline for the impact evaluation of Familias en Acción, a programme to foster the accumulation of human capital in rural Colombia, run by the Colombian government.
In this report, we will not describe in detail the programme or the methodology of the proposed evaluation, as this was done in IFS-Econometria-SEI (2003a). The main aim of the document is to discuss the first, baseline survey that was collected for this evaluation. While the baseline survey cannot, by definition, be used to perform impact evaluation, towards the end of the report we exploit the slightly peculiar way in which the programme was started and
have a first very preliminary glance at some of the impacts that the programme might have.
The methodological caveats on interpreting these results should be taken very seriously.
This report does not contain an extensive ‘fieldwork’ report. This is included in SEI (2003).
Analogously, we do not discuss extensively the operation of the programme and the evidence that emerged on related issues and on targeting. These issues are covered in IFS-Econometria- SEI (2003b, 2003c). We will be referring to some of the issues raised in those reports, however.
This report is divided into five chapters. In Chapter 1, we briefly summarise the main features of the programme and its proposed evaluation. A more detailed description of both of these aspects is contained in IFS-Econometria-SEI (2003a). Here, however, we give some details on the expansion of the programme and on the features of this expansion that allow a first and preliminary analysis of the impact of the programme. In Chapter 2, we describe the statistical methodology that will be used in the report. This includes the methodology for the data description that constitutes the largest part of the report and for the preliminary impact evaluation. Chapter 3 describes the baseline survey. This chapter is divided into several
sections, each referring to a particular module. In each section, we first describe the ‘treatment’ population – that is, the households eligible for the programme that were living in villages targeted by the programme. We then move on to the population living in ‘control’ villages –
that is, in villages that were not targeted by the programme and yet are, nonetheless, reasonably similar to the treatment villages. Chapter 4 presents the preliminary impact evaluation
Plankton blooms in vortices: The role of biological and hydrodynamic time scales
We study the interplay of hydrodynamic mesoscale structures and the growth of
plankton in the wake of an island, and its interaction with a coastal
upwelling. Our focus is on a mechanism for the emergence of localized plankton
blooms in vortices. Using a coupled system of a kinematic flow mimicking the
mesoscale structures behind the island and a simple three component model for
the marine ecosystem, we show that the long residence times of nutrients and
plankton in the vicinity of the island and the confinement of plankton within
vortices are key factors for the appearance of localized plankton bloomsComment: 29 pages, 9 figure
Biological activity in the wake of an island close to a coastal upwelling
Hydrodynamic forcing plays an important role in shaping the dynamics of
marine organisms, in particular of plankton. In this work we study the
planktonic biological activity in the wake of an island which is close to an
upwelling region. Our research is based on numerical analysis of a kinematic
flow mimicking the hydrodynamics in the wake, coupled to a three-component
plankton model. Depending on model parameters different phenomena are
described: a) The lack of transport of nutrients and plankton across the wake,
so that the influence of upwelling on primary production on the other side of
the wake is blocked. b) For sufficiently high vorticity, the role of the wake
in facilitating this transport and leading to an enhancement of primary
production. Finally c) we show that under certain conditions the interplay
between wake structures and biological growth leads to plankton blooms inside
mesoscale hydrodynamic vortices that act as incubators of primary production.Comment: 42 pages, 9 figure
Modelling the Product Development performance of Colombian Companies
Organised by: Cranfield UniversityThis paper presents the general model of the Product Development Process (PDP) in the Metal mechanics
Industry in Barranquilla-Colombia, since this sector contributes significantly to the productivity of this
industrial city. This case study counted on a five-company sample. The main goal was to model the current
conditions of the PDP according to the Concurrent Engineering philosophy. The companies were selected
according to their productive profile, in order to contrast differences regarding the structure of their
productive processes, conformation of multidisciplinary teams, integration of different areas, customers and
suppliers to the PDP; human resources, information, technology and marketing constraints.Mori Seiki – The Machine Tool Compan
Wide binaries as a critical test for Gravity theories
Assuming Newton's gravity and GR to be valid at all scales leads to the dark
matter hypothesis as a requirement demanded by the observed dynamics and
measured baryonic content at galactic and extragalactic scales. Alternatively,
modified gravity scenarios where a change of regime appears at acceleration
scales have been proposed. This modified regime at will
generically be characterised by equilibrium velocities which become independent
of distance. Here we identify a critical test in this debate and we propose its
application to samples of wide binary stars. Since for systems
the acceleration drops below at scales of around 7000 AU, a statistical
survey of wide binaries with relative velocities and separations reaching
AU and beyond should prove useful to the above debate. We apply the
proposed test to the best currently available data. Results show a constant
upper limit to the relative velocities in wide binaries which is independent of
separation for over three orders of magnitude, in analogy with galactic flat
rotation curves in the same acceleration regime. Our results are
suggestive of a breakdown of Kepler's third law beyond
scales, in accordance with generic predictions of modified gravity theories
designed not to require any dark matter at galactic scales and beyond.Comment: 4 pages 1 figure, Proceedings of the COSGRAV12 meeting, Kolkata,
India, 7th - 11th February, 201
Strong one-pion decay of , and
Working in the framework of a nonrelativistic quark model we evaluate the
widths for the strong one-pion decays ,
and . We take advantage of
the constraints imposed by heavy quark symmetry to solve the three-body problem
by means of a simple variational ansatz. We use partial conservation of the
axial current hypothesis to get the strong vertices from weak axial current
matrix elements. Our results are in good agreement with experimental data.Comment: 3 latex pages. Contribution to the Proceedings of the Quark
Confinement and the Hadron Spectrum VII Conference (QCHS7) Ponta Delgada (PT)
Sept 2-7, 200
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