Ceramide in the Outer Mitochondrial Membrane and its Role in Apoptosis

"Ceramides constitute a class of lipids found in different locations such as the outer mitochondrial membrane (OMM), whose permeabilization is a point-of-no-return in apoptosis. This phenomenon has been linked to the Voltage Dependent Anion Channel (VDAC), with which Ceramides can interact via a membrane-buried Glutamate residue in isoforms 1 and 2. To study the role of Ceramides in apoptosis, a Coarse Grain (CG) model of this lipid was created and subsequently optimized in terms of Solvent Accessible Surface Area and topology parameters. The latter were developed through a trial-and-error approach until the CG behavior resembled the atomistic references. The obtained parameters were further tested but results were inconclusive, probably due to the method used. Nevertheless, preliminary data demonstrated the model to properly interact with the Glutamate of VDAC."N/

Some aspects of the synchronization in coupled maps

Through numerical simulations we analyze the synchronization time and the Lyapunov dimension of a coupled map lattice consisting of a chain of chaotic logistic maps exhibiting power law interactions. From the observed behaviors we find a lower bound for the size $N$ of the lattice, independent of the range and strength of the interaction, which imposes a practical lower bound in numerical simulations for the system to be considered in the thermodynamic limit. We also observe the existence of a strong correlation between the averaged synchronization time and the Lyapunov dimension. This is an interesting result because it allows an analytical estimation of the synchronization time, which otherwise requires numerical simulations.Comment: 4 pages, 6 figure

Connect to success consulting program Liliana Alves Jewelry Design

This Work Project includes a business plan and an internationalization strategy for a Portuguese jewelry designer Liliana Alves. The purpose of the business plan is to evaluate the current situation of the company in the Portuguese market and find ways to improve it, while the internationalization strategy aims to increase revenues by expanding the operations abroad. The main suggestions comprise of unifying the inconsistent distribution strategy, taking advantage of time-reducing production processes, and increasing the margins through lowering fixed costs. Furthermore, current and potential internationalization locations are analyzed and entry strategies suggested

Synchronization time in a hyperbolic dynamical system with long-range interactions

We show that the threshold of complete synchronization in a lattice of coupled non-smooth chaotic maps is determined by linear stability along the directions transversal to the synchronization subspace. We examine carefully the sychronization time and show that a inadequate observation of the system evolution leads to wrong results. We present both careful numerical experiments and a rigorous mathematical explanation confirming this fact, allowing for a generalization involving hyperbolic coupled map lattices.Comment: 22 pages (preprint format), 4 figures - accepted for publication in Physica A (June 28, 2010

Validity of numerical trajectories in the synchronization transition of complex systems

We investigate the relationship between the loss of synchronization and the onset of shadowing breakdown {\it via} unstable dimension variability in complex systems. In the neighborhood of the critical transition to strongly non-hyperbolic behavior, the system undergoes on-off intermittency with respect to the synchronization state. There are potentially severe consequences of these facts on the validity of the computer-generated trajectories obtained from dynamical systems whose synchronization manifolds share the same non-hyperbolic properties.Comment: 4 pages, 4 figure

On the consistency of a repulsive gravity phase in the early Universe

We exploit the possibility of existence of a repulsive gravity phase in the evolution of the Universe. A toy model with a free scalar field minimally coupled to gravity, but with the "wrong sign" for the energy and negative curvature for the spatial section, is studied in detail. The background solutions display a bouncing, non-singular Universe. The model is well-behaved with respect to tensor perturbations. But, it exhibits growing models with respect to scalar perturbations whose maximum occurs in the bouncing. Hence, large inhomogeneties are produced. At least for this case, a repulsive phase may destroy homogeneity, and in this sense it may be unstable. A newtonian analogous model is worked out; it displays qualitatively the same behaviour. The generality of this result is discussed. In particular, it is shown that the addition of an attractive radiative fluid does not change essentially the results. We discuss also a quantum version of the classical repulsive phase, through the Wheeler-de Witt equation in mini-superspace, and we show that it displays essentially the same scenario as the corresponding attractive phase.Comment: Latex file, 15 pages, 7 figures. There is a new figure, a new section and some other minor correction

Troubles with quantum anistropic cosmological models: Loss of unitarity

The anisotropic Bianchi I cosmological model coupled with perfect fluid is quantized in the minisuperspace. The perfect fluid is described by using the Schutz formalism which allows to attribute dynamical degrees of freedom to matter. A Schr\"odinger-type equation is obtained where the matter variables play the role of time. However, the signature of the kinetic term is hyperbolic. This Schr\"odinger-like equation is solved and a wave packet is constructed. The norm of the resulting wave function comes out to be time dependent, indicating the loss of unitarity in this model. The loss of unitarity is due to the fact that the effective Hamiltonian is hermitian but not self-adjoint. The expectation value and the bohmian trajectories are evaluated leading to different cosmological scenarios, what is a consequence of the absence of a unitary quantum structure. The consistency of this quantum model is discussed as well as the generality of the absence of unitarity in anisotropic quantum models.Comment: Latex file, 18 pages. To appear in General Relativity and Gravitatio

A EDUCAÇÃO AMBIENTAL NA PERSPECTIVA DE FORMAÇÃO PARA A PARTICIPAÇÃO SOCIAL DAS POPULAÇÕES QUILOMBOLAS

O presente artigo tem como objetivo analisar o papel da educação ambiental na perspectiva de formação para a participação social das populações quilombolas. Para isso, a metodologia utilizada, contou com a realização de uma revisão bibliográfica e documental que substanciasse a temática apresentada. A humanidade hodiernamente se depara com a necessidade de mudanças bruscas para garantir um equilíbrio que promova o desenvolvimento humano sem comprometer a sadia qualidade de vida para as gerações futuras. A superação do atual modelo de desenvolvimento socioambiental constitui o desafio para todas as populações, mas em especial, as quilombolas. A não valorização de seus saberes tradicionais contribui para a perpetuação das desigualdades sociais e culturais. A educação ambiental pode abrir caminhos para a superação das atuais estruturas políticas, culturais e econômicas, enquanto simultaneamente desafia o olhar colonial que historicamente marginalizou e subestimou essas comunidades. Concluiu-se que a educação ambiental desempenha um papel fundamental na formação das lideranças e no fortalecimento das redes e associações quilombolas, permitindo que essas comunidades sejam protagonistas na defesa de seus direitos e na construção de políticas públicas voltadas para a sustentabilidade e a justiça ambiental. Ao promover a conscientização, o conhecimento e a ação, a educação ambiental capacita os cidadãos a serem agentes de mudança, promovendo a colaboração, o diálogo e a tomada de decisões coletivas em prol do meio ambiente

Analytical results for coupled map lattices with long-range interactions

We obtain exact analytical results for lattices of maps with couplings that decay with distance as $r^{-\alpha}$. We analyze the effect of the coupling range on the system dynamics through the Lyapunov spectrum. For lattices whose elements are piecewise linear maps, we get an algebraic expression for the Lyapunov spectrum. When the local dynamics is given by a nonlinear map, the Lyapunov spectrum for a completely synchronized state is analytically obtained. The critical lines characterizing the synchronization transition are determined from the expression for the largest transversal Lyapunov exponent. In particular, it is shown that in the thermodynamical limit, such transition is only possible for sufficiently long-range interactions, namely, for $\alpha\le alpha_c<d$, where $d$ is the lattice dimension.Comment: 4 pages, 2 figures, corrections included. Phys. Rev. E 68, 045202(R) (2003); correction in pres

Endocrine profiles and ovulation rate of cows superovulated with FSH following passive immunization against steroid free-bovine follicular fluid

Ten multiparous non-lactating cows were randomly assigned to one of two groups. On days 8 to 12 after estrus, the first group was given 100 ml antiserum against steroid-free bovine follicular fluid (anti-bFF), which was produced in ovariectomized sheep. The second group (control) was given 100 ml nonimmune ovariectomized sheep serum. Six hours after injection, both groups were superovulated with FSH (18 NIH-FSH-S1 units) and LH (0.29 NIH-LH-S1 units) in a 4-day decreasing regime. On the morning of the third day a luteolytic dose of prostaglandin F2alpha analogue (cloprostenol) was given. Artificial inseminations (AI) were done 48 and 60 h later. Embryos were collected 7 days after AI by a nonsurgical method. Blood samples were taken throughout the experimental period and plasma concentrations of FSH, LH and progesterone were determined by radioimmunoassay. All cows from the immunized group, and 3 out of 5 cows in the control group, had more than 2 CL. There was no significant difference (P&gt;;0.05) in the ovulation rate between immunized and control groups (14.4 and 9.9, respectively). The number of recovered embryos was not significantly different (P&gt;;0.05) between groups, although cows immunized against bFF had a greater number of transferable embryos (3.4 ± 1.0 versus 0.8 ± 0.4, P&lt;0.05). Plasma gonadotrophin concentrations were not correlated with either ovulation rate or number of recovered embryos. Plasma progesterone concentration was positively correlated (r = 0.88, P&lt;0.01) to ovulation rate. Results suggested that passive immunization of cows with anti-bFF before superovulation did not reduce the variability of ovarian response.Dez vacas multíparas, secas, foram distribuídas aleatoriamente em dois grupos de cinco animais cada. Nos dias 8 a 12 do diestro, o primeiro grupo recebeu 100 ml de anti-soro contra líquido folicular livre de esteróides (anti-LFb) produzido em ovelhas ovariectomizadas. O segundo grupo (controle) recebeu 100 ml de soro de ovelhas não-imunizadas. Seis horas após a aplicação, os dois grupos foram superovulados com FSH (18 NIH-FSH-S1 unidades) e LH (0,29 NIH-LH-S1 unidades) administrados em quantidades decrescentes durante quatro dias. Na manhã do terceiro dia, foi administrada uma dose luteolítica de cloprostenol. Duas inseminações foram realizadas 48 e 60 horas após. Os embriões foram recuperados pelo método cervical 7 dias após a primeira inseminação. Amostras de sangue foram coletadas durante todo o período experimental para determinar, por radioimunoensaio, as concentrações plasmáticas de FSH, LH e progesterona. Todas as vacas do grupo imunizado e 3 do grupo controle apresentaram mais de 2 CL. Não existiu diferença significativa (P&gt;;0,05) na taxa de ovulação entre os grupos imunizado e controle (14,4 e 9,9, respectivamente). O número de embriões recuperado não foi significativamente diferente (P&gt;;0,05) entre os grupos, embora o grupo imunizado tenha apresentado maior número de embriões transferíveis (3,4 ± 1,0 versus 0,8 ± 0,4, P&lt;0,05). As concentrações de gonadotrofinas plasmáticas não foram correlacionadas com a taxa de ovulação ou com o número de embriões recuperados. As concentrações de progesterona plasmática foram positivamente correlacionadas (r = 0,88, P&lt;0,01) com a taxa de ovulação. Os resultados sugerem que o anti-LFb, aplicado antes da superovulação, não reduz a variabilidade da resposta ovariana