304 research outputs found
Traditional systems of goat management. III. Reproductive performance of SRD (Non-descript) does and kid mortality.
Abstract: The reproductive performance of 50 adult SRD does maintained in native caatinga pasture at a stocking rate of 1 to 1.5 ha/head/year was evaluated. Two bucks were used in natural matings from September 1978 until December 1980. A total of 93 kiddings and 28 abortions occurred. Three pregnancies occurred before initiation of the experiment. From the 90 parturitions, 57.7%, 35.6%, 1.1 % and 5.6% bore singles, twins, triplets and undetermined, respectively. The flock showed an overall prolificacy of 1.38. From the initial fIock, 15(30%), 28(56%), 5(10%) and 2(4%) does presented one, two, three and zero kiddings, respectively during the period of study. Neither gestation length nor kidding interval were influenced by type of birth. Length of open period was influenced by season of the year when data were classified by season and kidding status at the open period. Combination of kidding type at previous and following kiddings showed a significant influence (P < 0.05) on the length of the open period. AnimaIs which kidded first singles and then singles or twins showed a shorter open period than animaIs which firstly kidded twins and then aborted at the following pregnant (109 Ys 188 days). The peak of kid mortality occurred between 7 and 112 days of age. Kid mortality appears not to be influenced by sex or type of birth. Overall kid mortality was 76%. The age at dead of kids was influenced by season and sex as weil as by their interaction. Males bom during the rainyseason survived longer than any other class studied. [Sistema tradicional de manejo de caprinos. III. Desempenho reprodutivo de caprinos SRD e mortalidade de cabritos]. Resumo: Avaliou-se o desempenho de 50 fêmeas de cabras SRD adultas mantidas em um piquete de pastagem nativa com uma lotação de 1 a 1,5 ha/cab/ano. Neste rebanho, dois reprodutores foram usados em monta natural de setembro de 1978 a dezembro de 1980. Foram observados 93 partos e 28 abortos. Ocorreram três prenhezes antes do início do experimento. Dos 90 partos restantes, 57,1%, 35,6%, 1,1% e 5,6% forem simples, duplos, triplos e não determinados, respectivamente. O rebanho mostrou uma prolificidade de 1,38. Para o rebanho inicial 15 (30%), 28 (56%), 5 (10%) e 2 (4%) das cabras pariram uma, duas, três e nenhuma vez, respectivamente, durante o período estudado. O período de gestação e o intervalo entre os partos não foram influenciados pelo tipo de nascimento. O período vazio foi influenciado pela estação do ano, quando os dados foram classificados por estação e tipo de parto. A combinação do tipo de parto, na parição inicial e na parição seguinte, teve influência significativa no período vazio. Os animais que pariram primeiramente simples e depois simples ou duplos apresentaram um período vazio menor (109 vs 188 dias) do que os animais que pariram primeiramente múltiplos e depois abortaram na prenhez seguinte. O pique de mortalidade (32%) ocorreu entre 7 e 112 dias de idade. A mortalidade de cabritos parece não ter sido influenciada pelo sexo e tipo de nascimento. A mortalidade total das crias foi de 76%. A idade à morte desses animais foi influencieda pela estação, sexo e interação de ambos. Os machos nascidos durante a estação chuvosa sobreviveram mais tempo do que os nascidos nas outras classes estudadas
Cosmological Implications of a Non-Separable 5D Solution of the Vacuum Einstein Field Equations
An exact class of solutions of the 5D vacuum Einstein field equations (EFEs)
is obtained. The metric coefficients are found to be non-separable functions of
time and the extra coordinate and the induced metric on = constant
hypersurfaces has the form of a Friedmann-Robertson-Walker cosmology. The 5D
manifold and 3D and 4D submanifolds are in general curved, which distinguishes
this solution from previous ones in the literature. The singularity structure
of the manifold is explored: some models in the class do not exhibit a big
bang, while other exhibit a big bang and a big crunch. For the models with an
initial singularity, the equation of state of the induced matter evolves from
radiation like at early epochs to Milne-like at late times and the big bang
manifests itself as a singular hypersurface in 5D. The projection of comoving
5D null geodesics onto the 4D submanifold is shown to be compatible with
standard 4D comoving trajectories, while the expansion of 5D null congruences
is shown to be in line with conventional notions of the Hubble expansion.Comment: 8 pages, in press in J. Math. Phy
Traditional system of goat management. II. Postweaning growth performance of the SRD (Nondescript) goats.
Abstract: The pattern of growth of SRD kids from an average of 153 days up to approximately 461 days of age was studied. Weights at the ages of 153 (W 5 ), 181 (W5), 209 (W7 ), 237 (W8 ), 265 (W9 ), 293 (W10 ), 321 (VI 1 ), 349 (W1 2), 461 (W15 ) days and calculated weight gains (G) between every weight interval G5 - (W5 - Weaning weight) through G12 - (W1 2 - W 1 ) were evaluated. Data were initially recorded on 54 kids and diminished thereafter at every interval due to kid mortaiity. The least squares analysis of vaiiance showed a significant season of birth effect (P 0.05) with the exception of type of birth for G 12 (P 0,05), com excecao do tipo de nascimento para G12 (P<0,025). As covariancias de peso da mae ao parto e idade do cabrito no momento da pesagem, foram significativas em algumas idades. Ja para o peso ao nascer, a covariavel foi significativa para P7, P8, P10 (P<0,005), P9 (P<0,001), P6, P11 e G12 (P<0,025)
Effective spacetime from multi-dimensional gravity
We study the effective spacetimes in lower dimensions that can be extracted
from a multidimensional generalization of the Schwarzschild-Tangherlini
spacetimes derived by Fadeev, Ivashchuk and Melnikov ({\it Phys. Lett,} {\bf A
161} (1991) 98). The higher-dimensional spacetime has
dimensions, where and are the number of "internal" and "external" extra
dimensions, respectively. We analyze the effective spacetime obtained
after dimensional reduction of the external dimensions. We find that when
the extra dimensions are compact (i) the physics in lower dimensions is
independent of and the character of the singularities in higher dimensions,
and (ii) the total gravitational mass of the effective matter distribution
is less than the Schwarzshild mass. In contrast, when the extra dimensions
are large this is not so; the physics in does explicitly depend on
, as well as on the nature of the singularities in high dimensions, and the
mass of the effective matter distribution (with the exception of wormhole-like
distributions) is bigger than the Schwarzshild mass. These results may be
relevant to observations for an experimental/observational test of the theory.Comment: A typo in Eq. (24) is fixe
Características espermáticas de caprinos Moxotó de acordo com a morfologia escrotal.
bitstream/item/36457/1/CT-06.pd
Reconstruction of Five-dimensional Bounce cosmological Models From Deceleration Factor
In this paper, we consider a class of five-dimensional Ricci-flat vacuum
solutions, which contain two arbitrary functions and . It is
shown that can be rewritten as a new arbitrary function in
terms of redshift and the can be determined by choosing particular
deceleration parameters which gives early deceleration and late time
acceleration. In this way, the cosmological model can be reconstructed and
the evolution of the universe can be determined.Comment: 5 pages, 1 figure, to be published in IJT
Self-similar cosmologies in 5D: Our universe as a topological separation from an empty 5D Minkowski space
In this paper we find the most general self-similar, homogeneous and
isotropic, Ricci flat cosmologies in 5D. These cosmologies show a number of
interesting features: (i) the field equations allow a complete integration in
terms of one arbitrary function of the similarity variable, and a free
parameter; (ii) the three-dimensional spatial surfaces are flat; (iii) the
extra dimension is spacelike; (iv) the general solution is Riemann-flat in 5D
but curved in 4D, which means that an observer confined to 4D spacetime can
relate this curvature to the presence of matter, as determined by the Einstein
equations in 4D. We show that these cosmologies can be interpreted, or used, as
5D Riemann-flat embeddings for spatially-flat FRW cosmologies in 4D. In this
interpretation our universe arises as a topological separation from an empty 5D
Minkowski space, as envisioned by Zeldovich
Stabilization of test particles in Induced Matter Kaluza-Klein theory
The stability conditions for the motion of classical test particles in an -dimensional Induced Matter Kaluza-Klein theory is studied. We show that
stabilization requires a variance of the strong energy condition for the
induced matter to hold and that it is related to the hierarchy problem.
Stabilization of test particles in a FRW universe is also discussed.Comment: 15 pages, 1 figure, to appear in Class. Quantum Gra
Active gravitational mass and the invariant characterization of Reissner-Nordstrom spacetime
We analyse the concept of active gravitational mass for Reissner-Nordstrom
spacetime in terms of scalar polynomial invariants and the Karlhede
classification. We show that while the Kretschmann scalar does not produce the
expected expression for the active gravitational mass, both scalar polynomial
invariants formed from the Weyl tensor, and the Cartan scalars, do.Comment: 6 pages Latex, to appear in General Relativity and Gravitatio
Embeddings in Spacetimes Sourced by Scalar Fields
The extension of the Campbell-Magaard embedding theorem to general relativity
with minimally-coupled scalar fields is formulated and proven. The result is
applied to the case of a self-interacting scalar field for which new embeddings
are found, and to Brans-Dicke theory. The relationship between Campbell-Magaard
theorem and the general relativity, Cauchy and initial value problems is
outlined.Comment: RevTEX (11 pages)/ To appear in the Journal of Mathematical Physic
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