2,590 research outputs found
Particle Pair Production in Cosmological General Relativity
The Cosmological General Relativity (CGR) of Carmeli, a 5-dimensional (5-D)
theory of time, space and velocity, predicts the existence of an acceleration
a_0 = c / tau due to the expansion of the universe, where c is the speed of
light in vacuum, tau = 1 / h is the Hubble-Carmeli time constant, where h is
the Hubble constant at zero distance and no gravity.
The Carmeli force on a particle of mass m is F_c = m a_0, a fifth force in
nature.
In CGR, the effective mass density rho_eff = rho - rho_c, where rho is the
matter density and rho_c is the critical mass density which we identify with
the vacuum mass density rho_vac = -rho_c.
The fields resulting from the weak field solution of the Einstein field
equations in 5-D CGR and the Carmeli force are used to hypothesize the
production of a pair of particles.
The mass of each particle is found to be m = tau c^3 / 4 G, where G is
Newton's constant.
The vacuum mass density derived from the physics is rho_vac = -rho_c = -3 /
(8 pi G tau^2).
The cosmic microwave background (CMB) black body radiation at the temperature
T_o = 2.72548 K which fills that volume is found to have a relationship to the
ionization energy of the Hydrogen atom. Define the radiation energy
epsilon_gamma = (1 - g) m c^2 / N_gamma, where (1-g) is the fraction of the
initial energy m c^2 which converts to photons, g is a function of the baryon
density parameter Omega_b and N_gamma is the total number of photons in the CMB
radiation field. We make the connection with the ionization energy of the first
quantum level of the Hydrogen atom by the hypothesis epsilon_gamma = [(1 - g) m
c^2] / N_gamma = alpha^2 mu c^2 / 2, where alpha is the fine-structure constant
and mu = m_p f / (1 + f), where f= m_e / m_p with m_e the electron mass and m_p
the proton mass.Comment: 14 pages, 0 figures. The final publication is available at
springerlink.co
Adubação não radicular com duas fontes de zinco em Coffea arábica L. "mundo novo" (B.Rodr.) Choussy
A trial was carried out on an eight old coffee plantation with visible zinc problems. The plantation was situated nearly the city of Jaú (22º30'S, 48º30'W). State of São Paulo, Brazil. The soil is classified as medium texture Oxisol of low base saturation (Latossol Vermelho Amarelo - fase arenosa). The pulverization program started in november 1977, followed in march and July 1978 (heavy harvest) and ended in march and July 1979 (light harvest). Is should be mentioned that a well reconized characteristic of arábica coffe is its habit of biennial bearing, a very heavy harvest is most often followed by a light load the next year. The following treatments and amounts of chemicals per cova hole (4 trees) were tested in accordance with a random block design: 1. 1 g of zinc (zinc sulphate, 0.5%) 2. 3 g of nitrogen (urea, 1.3%) 3. 1 g of zinc + 3 g of nitrogen (zinc sulphate 0.5% + urea 1.3%) 4. 0.25 g, 0.50 g, 1.00 g, 2.00 g of zinc plus 0.75 g, 1.50 g, 3.00 g and 6.00 of nitrogen (correspondent to NZN* 15-0-0-5 as 0.75%, 1-5%, 3.0% and 6.0% by v/v). Foliar absorption data were obtained by collecting the 3rd and 4th pairs of the coffee leaves and analysed them for N, P, K, Ca, Mg, S, B, Cu, Fe, Mn, and Zn. The main results may be summarized as follows: 1. The maximum calculated yields of clean coffee were obtained by the applications of 5.84 1 of NZN (1.13%) per hectare. 2. The applications of zinc sulphate (0.5%) and urea (1.3%) together or separate did not affected the coffee bean production. 3. The applications of 15.0 1 of NZN per hectare reduced the coffee yields. 4. Leaf damages and burning symptoms were observed by the applications of urea (1.3%) plus zinc sulphate (0.5%) and larger doses than 7.5 1 of NZN per hectare. 5. Leaf tissue analysis show that the concentrations of the elements were affecred by the age of the leaves and by the yields of the coffee trees. 6. The applications of increasing doses of NZN causes an increase in the concentration of zinc, manganese and boron in the leaves and decreased the concentration in calcium and potassium the leaves. 7. The concentration of zinc in the leaves associated with the heavy harvest, in July, was 70.0 ppm.Em cafezal com 8 anos de idade, com deficiência visível de zinco, situado em um Latossol Amarelo - fase arenosa, do município de Jaú, SP, procederam-se pulverizações em novembro, março e julho de 1978 (grande safra) e março e julho de 1979 (pequena safra), O delineamento experimental foi de blocos ao acaso e constou dos seguintes tratamentos, nas doses por planta: lg de zinco (sulfato de zinco 0,5%), 3g de nitrogênio (uréia 1,3%), lg de zinco + 3g de nitrogênio (sulfato de zinco 0,5% + uréia 1,3%) e 0,25g, 0,50g, 1 ,00g e 2,00g de zinco juntamente com 0,75g, l,50g, 3,00g e 6,00g de nitrogênio (respectivamente NZN 15-0-0-5 * a 0,75%, 3,00% e 6,00% v/v). Na época das pulverizaçoes foram coletadas amostras de 3º e 4º pares de folhas, e determinados os teores de nitrogênio, fósforo, potássio, cálcio, magnésio, boro, cobre, ferro, manganês e zinco. Os resultados mostraram que: a) a produção máxima calculada de café beneficiado foi 3-009,4 kg/ha, obtida com pulverizaçao de 5,84 1 de NZN por hectare (NZN 1 ,17%) ; b) o sulfato de zinco e a uréia, juntos ou isoladamente, não afetaram a produção; c) a dose de 15,0 1 de NZN por hectare diminuiu a produção; d) as aplicações de uréia (1,3%) + sulfato de zinco (0,5%) e de doses de NZN superiores a 7,51/ha provocaram injúrias visíveis nas folhas. Esse efeitos se agravaram com dosagens de 15 1 e 30 1 de NZN por hectare; e) as concentrações dos nutrientes nas folhas foram afetadas de maneira diferente pelas épocas de amostragem e pela produção do cafeeiro; f) a aplicação de doses crescentes de NZN provocou aumento nas concentrações de zinco, manganês e boro e diminuição nas de cálcio e potássio nas folhas, em determinadas épocas da grande ou pequena safra; g) a concentração de zinco em julho, relacionada com a maior produção do cafeeiro, foi 70 ppm
Gravitational non-commutativity and G\"odel-like spacetimes
We derive general conditions under which geodesics of stationary spacetimes
resemble trajectories of charged particles in an electromagnetic field. For
large curvatures (analogous to strong magnetic fields), the quantum
mechanicical states of these particles are confined to gravitational analogs of
{\it lowest Landau levels}. Furthermore, there is an effective
non-commutativity between their spatial coordinates. We point out that the
Som-Raychaudhuri and G\"odel spacetime and its generalisations are precisely of
the above type and compute the effective non-commutativities that they induce.
We show that the non-commutativity for G\"odel spacetime is identical to that
on the fuzzy sphere. Finally, we show how the star product naturally emerges in
Som-Raychaudhuri spacetimes.Comment: Two sections added (Relation to the fuzzy sphere, Emergence of the
star product). 10 pages, Revtex. To appear in General Relativity and
Gravitatio
Modelling the electric field applied to a tokamak
The vector potential for the Ohmic heating coil system of a tokamak is
obtained in semi-analytical form. Comparison is made to the potential of a
simple, finite solenoid. In the quasi-static limit, the time rate of change of
the potential determines the induced electromotive force through the
Maxwell-Lodge effect. Discussion of the gauge constraint is included.Comment: 13 pages, 7 figures, final versio
Nature of singularity formed by the gravitational collapse in Husain space-time with electromagnetic field and scalar field
In this work, we have investigated the outcome of gravitational collapse in
Husain space-time in the presence of electro-magnetic and a scalar field with
potential. In order to study the nature of the singularity, global behavior of
radial null geodesics have been taken into account. The nature of singularities
formed has been thoroughly studied for all possible variations of the
parameters. These choices of parameters has been presented in tabular form in
various dimensions. It is seen that irrespective of whatever values of the
parameters chosen, the collapse always results in a naked singularity in all
dimensions. There is less possibility of formation of a black hole. Hence this
work is a significant counterexample of the cosmic censorship hypothesis.Comment: 9 pages, 19 figure
Gravitational Collapse in Higher Dimensional Husain Space-Time
We investigate exact solution in higher dimensional Husain model for a null
fluid source with pressure and density are related by the following
relations (i) , (ii) (variable
modified Chaplygin) and (iii) (polytropic). We have studied
the nature of singularity in gravitational collapse for the above equations of
state and also for different choices of the of the parameters and
namely, (i) , constant (generalized Chaplygin), (ii) constant
(modified Chaplygin). It is found that the nature of singularity is independent
of these choices of different equation of state except for variable Chaplygin
model. Choices of various parameters are shown in tabular form. Finally,
matching of Szekeres model with exterior Husain space-time is done.Comment: 12 latex pages, No figure, RevTex styl
Description Of Rhodnius Marabaensis Sp. N. (hemiptera, Reduviidade, Triatominae) From Pará State, Brazil
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Rhodnius marabaensis sp. n. was collected on 12 May 2014 in the Murumurú Environmental Reserve in the city of Marabá, Pará State, Brazil. This study was based on previous consultation of morphological descriptions of 19 Rhodnius species and compared to the identification key for the genus Rhodnius. The examination included specimens from 18 Rhodnius species held in the Brazilian National and International Triatomine Taxonomy Reference Laboratory in the Oswaldo Cruz Institute in Rio de Janeiro, Brazil. The morphological characteristics of the head, thorax, abdomen, genitalia, and eggs have been determined. Rhodnius prolixus and R. robustus were examined in more detail because the BLAST analysis of a cyt-b sequence shows they are closely related to the new species, which also occurs in the northern region of Brazil. The most notable morphological features that distinguish R. marabaensis sp. n. are the keel-shaped apex of the head, the length of the second segment of the antennae, the shapes of the prosternum, mesosternum and metasternum, the set of spots on the abdomen, the male genitalia, the posterior and ventral surfaces of the external female genitalia, and the morphological characteristics of the eggs. Rhodnius jacundaensis Serra, Serra and Von Atzingen (1980) nomen nudum specimens deposited at the Maraba Cultural Center Foundation - MCCF were examined and considered as a synonym of R. marabaensis sp. n. © Eder dos Santos Souza et al.201662145622010/15386-3, FAPESP, Fundação de Amparo à Pesquisa do Estado de São Paulo23038-005285/2011-2012, CAPES, Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorCNPq, Conselho Nacional de Desenvolvimento Científico e TecnológicoFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq
Tuberculosis determined by Mycobacterium bovis in captive waterbucks (Kobus ellipsiprymnus) in São Paulo, Brazil
Two waterbucks from São Paulo Zoo Foundation exhibited respiratory symptoms in July 2004. After euthanasia, granulommas in lungs and mediastinic lymph nodes were observed. Acid-fast bacilli isolated were identified as Mycobacterium bovis spoligotype SB0121 by PRA and spoligotyping. They were born and kept in the same enclosure with the same group, without any contact to other species housed in the zoo. This is the first detailed description of M. bovis infection in Kobus ellipsiprymnus.FAPES
Space-time inhomogeneity, anisotropy and gravitational collapse
We investigate the evolution of non-adiabatic collapse of a shear-free
spherically symmetric stellar configuration with anisotropic stresses
accompanied with radial heat flux. The collapse begins from a curvature
singularity with infinite mass and size on an inhomogeneous space-time
background. The collapse is found to proceed without formation of an even
horizon to singularity when the collapsing configuration radiates all its mass
energy. The impact of inhomogeneity on various parameters of the collapsing
stellar configuration is examined in some specific space-time backgrounds.Comment: To appear in Gen. Relativ. Gra
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