Sound waves and solitons in hot and dense nuclear matter

Assuming that nuclear matter can be treated as a perfect fluid, we study the propagation of perturbations in the baryon density. The equation of state is derived from a relativistic mean field model, which is a variant of the non-linear Walecka model. The expansion of the Euler and continuity equations of relativistic hydrodynamics around equilibrium configurations leads to differential equations for the density perturbation. We solve them numerically for linear and spherical perturbations and follow the propagation of the initial pulses. For linear perturbations we find single soliton solutions and solutions with one or more solitons followed by ""radiation"". Depending on the equation of state a strong damping may occur. We consider also the evolution of perturbations in a medium without dispersive effects. In this case we observe the formation and breaking of shock waves. We study all these equations also for matter at finite temperature. Our results may be relevant for the analysis of RHIC data. They suggest that the shock waves formed in the quark gluon plasma phase may survive and propagate in the hadronic phase. (C) 2009 Elseiver. B.V. All rights reserved.

Development and fabrication of an optimized thermo-electro-optic device using a Mach-Zehnder interferometer

The development and fabrication of a thermo-electro-optic sensor using a Mach-Zehnder interferometer and a resistive micro-heater placed in one of the device`s arms is presented. The Mach-Zehnder structure was fabricated on a single crystal silicon substrate using silicon oxynitride and amorphous hydrogenated silicon carbide films to form an anti-resonant reflective optical waveguide. The materials were deposited by Plasma enhanced chemical vapor deposition technique at low temperatures (similar to 320 degrees C). To optimize the heat transfer and increase the device response with current variation, part of the Mach-Zehnder sensor arm was suspended through front-side bulk micromachining of the silicon substrate in a KOH solution. With the temperature variation caused by the micro-heater, the refractive index of the core layer of the optical waveguide changes due to the thermo-optic effect. Since this variation occurs only in one of the Mach-Zehnder`s arm, a phase difference between the arms is produced, leading to electromagnetic interference. In this way, the current applied to the micro-resistor can control the device output optical power. Further, reactive ion etching technique was used in this work to define the device`s geometry, and a study of SF6 based etching rates on different composition of silicon oxynitride films is also presented. (C) 2007 Elsevier B.V. All rights reserved.

Elaboração de um manual de fabrico de cones

O cone de bolacha é um produto alimentar muito consumido, pois está associado ao gelado, que é um produto de muito sucesso. O cone de bolacha é o resultado de uma mistura de ingredientes (farinha de trigo, açúcar, lecitina de soja, amido de batata, caramelo, água e sal) que é homogeneizada e cozida. O seu fabrico percorre vários processos de produção, que vão desde a formulação da receita, até ao armazenamento do produto e à sua transferência para a Fábrica de Gelados da Olá, para a produção do gelado Cornetto. Como a garantia da qualidade dos produtos alimentares, e deste em particular, é de uma extrema importância, torna-se relevante o estudo de todos os seus mecanismos de fabrico, e dos parâmetros de controlo indispensáveis para o êxito do produto, e para a segurança do consumidor. Para garantir a manutenção da qualidade são apresentadas ferramentas de TPM. O objetivo principal desta Dissertação é apresentar um Manual de fabrico de Cones de Bolacha. Para a sua elaboração focaram-se não só as áreas de produção e de tecnologia, mas também as áreas de gestão, de qualidade e segurança alimentar. O estudo subjacente a este trabalho, realizou-se na nova Fábrica de Cones da Olá, situada em Santa Iria da Azóia.

Reduction theorems for operators on the cones of monotone functions

For a quasilinear operator on the semiaxis a reduction theorem is proved on the cones of monotone functions in Lp - Lq setting for 0 < q < ∞, 1<= p < ∞. The case 0 < p < 1 is also studied for operators with additional properties. In particular, we obtain critera for three-weight inequalities for the Hardy-type operators with Oinarov' kernel on monotone functions in the case 0 < q < p <= 1.

Consumer Advisory Bulletin, Prevent Home Repair Scams and Disputes, Mach 2008

The Attorney General’s Consumer Protection Division receives hundreds of calls and consumer complaints every year. Follow these tips to avoid unexpected expense and disappointments. This record is about: Prevent Home Repair Scams and Disputes

Regulated exocytosis of an H+/myo-inositol symporter at synapses and growth cones.

Phosphoinositides, synthesized from myo-inositol, play a critical role in the development of growth cones and in synaptic activity. As neurons cannot synthesize inositol, they take it up from the extracellular milieu. Here, we demonstrate that, in brain and PC12 cells, the recently identified H(+)/myo-inositol symporter HMIT is present in intracellular vesicles that are distinct from synaptic and dense-core vesicles. We further show that HMIT can be triggered to appear on the cell surface following cell depolarization, activation of protein kinase C or increased intracellular calcium concentrations. HMIT cell surface expression takes place preferentially in regions of nerve growth and at varicosities and leads to increased myo-inositol uptake. The symporter is then endocytosed in a dynamin-dependent manner and becomes available for a subsequent cycle of stimulated exocytosis. HMIT is thus expressed in a vesicular compartment involved in activity-dependent regulation of myo-inositol uptake in neurons. This may be essential for sustained signaling and vesicular traffic activities in growth cones and at synapses.

El origen de la construcción fenomenalista: Mach, Moore y Whitehead

It's usually believed that the idea of applying logical methods to constructivist phenomenalism was, --in general- a result of Russell's originality. In this paper is argued that some important ideas were in fact due to Mach, Moore and Whitehead. According to the author, Russell got from Mach the general idea of epistemology as an analysis of scientific concepts and, specially,the idea of sensations as the building blocks for his logical construction. Moore made Russell believe that only sensations are known in a direct way, and so, the existence of external objects as the cause of our perceptions is only inferred. Moreover, according to the author, Russell's views on sense data -his sensibilia- are also due to Moore. Finally, Russell got from Whitehead the idea of the phenomenical reconstruction as an alternative to the causal theory of perception, and also how the logical construction should be done. The author undertakes also a detailed analysis of some early works of Whitehead not very well known.

Dosimetria dos cones radiocirúrgicos Radionics de diâmetros de 5 mm a 50 mm para um feixe de 6 MV de um acelerador linear Mevatron MD digital

Os parâmetros dosimétricos de um feixe de raios X de pequeno diâmetro para um sistema de radiocirurgia comercial foram medidos em água com um detector de diodo de Si do tipo p. As razões tecido-máximo, o fator de espalhamento total e os perfis dos feixes a profundidades de 5 e 10 cm foram medidos para 17 feixes de diâmetros circulares de 5 mm a 50 mm, em incrementos de 2,5 mm. Os fatores de espalhamento totais caíram lentamente, de 0,947 para 0,888 entre os cones de 50 mm e 12,5 mm de diâmetro (variação de 7%); para os cones entre 10 mm e 5 mm de diâmetro, esta queda foi bem maior, de 0,854 para 0,666 (variação de 28%). Os valores obtidos para a relação tecido-máximo são consistentes com dados publicados. Os perfis dos feixes foram medidos nas direções x e y, e estão dentro de 0,2 mm para todos os cones entre as duas direções. A medida da largura à meia-altura se encontra dentro de 1 mm com o diâmetro nominal dos cones.

A signaling mechanism coupling netrin-1/deleted in colorectal cancer chemoattraction to SNARE-mediated exocytosis in axonal growth cones

Directed cell migration and axonal guidance are essential steps in neural development. Both processes are controlled by specific guidance cues that activate the signaling cascades that ultimately control cytoskeletal dynamics. Another essential step in migration and axonal guidance is the regulation of plasmalemma turnover and exocytosis in leading edges and growth cones. However, the cross talk mechanisms linking guidance receptors and membrane exocytosis are not understood. Netrin-1 is a chemoattractive cue required for the formation of commissural pathways. Here, we show that the Netrin-1 receptor deleted in colorectal cancer (DCC) forms a protein complex with the t-SNARE (target SNARE) protein Syntaxin-1 (Sytx1). This interaction is Netrin-1 dependent both in vitro and in vivo, and requires specific Sytx1 and DCC domains. Blockade of Sytx1 function by using botulinum toxins abolished Netrin-1-dependent chemoattraction of axons in mouse neuronal cultures. Similar loss-of-function experiments in the chicken spinal cord in vivo using dominant-negative Sytx1 constructs or RNAi led to defects in commissural axon pathfinding reminiscent to those described in Netrin-1 and DCC loss-of-function models. We also show that Netrin-1 elicits exocytosis at growth cones in a Sytx1-dependent manner. Moreover, we demonstrate that the Sytx1/DCC complex associates with the v-SNARE (vesicle SNARE) tetanus neurotoxin-insensitive vesicle-associated membrane protein (TI-VAMP) and that knockdown of TI-VAMP in the commissural pathway in the spinal cord results in aberrant axonal guidance phenotypes. Our data provide evidence of a new signaling mechanism that couples chemotropic Netrin-1/DCC axonal guidance and Sytx1/TI-VAMP SNARE proteins regulating membrane turnover and exocytosis.

A signaling mechanism coupling netrin-1/deleted in colorectal cancer chemoattraction to SNARE-mediated exocytosis in axonal growth cones

Directed cell migration and axonal guidance are essential steps in neural development. Both processes are controlled by specific guidance cues that activate the signaling cascades that ultimately control cytoskeletal dynamics. Another essential step in migration and axonal guidance is the regulation of plasmalemma turnover and exocytosis in leading edges and growth cones. However, the cross talk mechanisms linking guidance receptors and membrane exocytosis are not understood. Netrin-1 is a chemoattractive cue required for the formation of commissural pathways. Here, we show that the Netrin-1 receptor deleted in colorectal cancer (DCC) forms a protein complex with the t-SNARE (target SNARE) protein Syntaxin-1 (Sytx1). This interaction is Netrin-1 dependent both in vitro and in vivo, and requires specific Sytx1 and DCC domains. Blockade of Sytx1 function by using botulinum toxins abolished Netrin-1-dependent chemoattraction of axons in mouse neuronal cultures. Similar loss-of-function experiments in the chicken spinal cord in vivo using dominant-negative Sytx1 constructs or RNAi led to defects in commissural axon pathfinding reminiscent to those described in Netrin-1 and DCC loss-of-function models. We also show that Netrin-1 elicits exocytosis at growth cones in a Sytx1-dependent manner. Moreover, we demonstrate that the Sytx1/DCC complex associates with the v-SNARE (vesicle SNARE) tetanus neurotoxin-insensitive vesicle-associated membrane protein (TI-VAMP) and that knockdown of TI-VAMP in the commissural pathway in the spinal cord results in aberrant axonal guidance phenotypes. Our data provide evidence of a new signaling mechanism that couples chemotropic Netrin-1/DCC axonal guidance and Sytx1/TI-VAMP SNARE proteins regulating membrane turnover and exocytosis.

A signaling mechanism coupling netrin-1/deleted in colorectal cancer chemoattraction to SNARE-mediated exocytosis in axonal growth cones

Directed cell migration and axonal guidance are essential steps in neural development. Both processes are controlled by specific guidance cues that activate the signaling cascades that ultimately control cytoskeletal dynamics. Another essential step in migration and axonal guidance is the regulation of plasmalemma turnover and exocytosis in leading edges and growth cones. However, the cross talk mechanisms linking guidance receptors and membrane exocytosis are not understood. Netrin-1 is a chemoattractive cue required for the formation of commissural pathways. Here, we show that the Netrin-1 receptor deleted in colorectal cancer (DCC) forms a protein complex with the t-SNARE (target SNARE) protein Syntaxin-1 (Sytx1). This interaction is Netrin-1 dependent both in vitro and in vivo, and requires specific Sytx1 and DCC domains. Blockade of Sytx1 function by using botulinum toxins abolished Netrin-1-dependent chemoattraction of axons in mouse neuronal cultures. Similar loss-of-function experiments in the chicken spinal cord in vivo using dominant-negative Sytx1 constructs or RNAi led to defects in commissural axon pathfinding reminiscent to those described in Netrin-1 and DCC loss-of-function models. We also show that Netrin-1 elicits exocytosis at growth cones in a Sytx1-dependent manner. Moreover, we demonstrate that the Sytx1/DCC complex associates with the v-SNARE (vesicle SNARE) tetanus neurotoxin-insensitive vesicle-associated membrane protein (TI-VAMP) and that knockdown of TI-VAMP in the commissural pathway in the spinal cord results in aberrant axonal guidance phenotypes. Our data provide evidence of a new signaling mechanism that couples chemotropic Netrin-1/DCC axonal guidance and Sytx1/TI-VAMP SNARE proteins regulating membrane turnover and exocytosis.

Eletroestimulação funcional do assoalho pélvico versus terapia com os cones vaginais para o tratamento de incontinência urinária de esforço

OBJETIVO: comparar os efeitos da eletroestimulação funcional do assoalho pélvico e da terapia com os cones em mulheres com incontinência urinária de esforço (IUE). MÉTODOS: estudo clínico randomizado. Selecionamos 45 pacientes com IUE, avaliamos os efeitos da eletroestimulação funcional do assoalho pélvico no tratamento da IUE em 24 mulheres empregando dados clínicos (diário miccional, pad test e questionário de qualidade de vida - I-QoL). As pacientes se submeteram a duas sessões semanais, com duração de 20 minutos cada, durante quatro meses consecutivos, com supervisão de uma fisioterapeuta. Foi utilizado eletrodo de aproximadamente 10 cm de comprimento e 3,5 cm de largura, com duplo anel metálico e formato cilíndrico, posicionado no terço médio da vagina. Os parâmetros elétricos utilizados foram: intensidade de corrente variando de 10 a 100 mA e frequência fixa em 50 Hz com duração de pulso de 1 mili/seg. Avaliamos também 21 pacientes que se submeteram ao tratamento com cones vaginais. A terapia com os cones foi feita em duas sessões semanais com duração de 45 minutos. O peso dos cones variou de 20 a 100 g. RESULTADOS: não houve diferença entre os resultados da eletroestimulação para o assoalho pélvico e da terapia com os cones vaginais para o tratamento da incontinência urinária de esforço (p>0,05). Observamos, após quatro meses, melhora significativa dos índices de qualidade de vida das pacientes tratadas com eletroestimulação (40,3 versus 82,9) e com os cones (47,7 versus 84,1). Houve diminuição significante do peso do absorvente (pad test) nos dois grupos antes e depois do término dos tratamentos (28,5 e 32 g versus 2,0 e 3,0 g, para o grupo da eletroestimulação e cones, respectivamente). Finalmente, houve diminuição significativa no número de perdas urinárias avaliadas pelo diário miccional nos dois grupos (p<0,0001). CONCLUSÕES: a eletroestimulação e os cones vaginais foram efetivos no tratamento de mulheres com IUE.

Stability of preconditioned finite volume schemes at low Mach numbers

In [4], Guillard and Viozat propose a finite volume method for the simulation of inviscid steady as well as unsteady flows at low Mach numbers, based on a preconditioning technique. The scheme satisfies the results of a single scale asymptotic analysis in a discrete sense and comprises the advantage that this can be derived by a slight modification of the dissipation term within the numerical flux function. Unfortunately, it can be observed by numerical experiments that the preconditioned approach combined with an explicit time integration scheme turns out to be unstable if the time step Dt does not satisfy the requirement to be O(M2) as the Mach number M tends to zero, whereas the corresponding standard method remains stable up to Dt=O(M), M to 0, which results from the well-known CFL-condition. We present a comprehensive mathematical substantiation of this numerical phenomenon by means of a von Neumann stability analysis, which reveals that in contrast to the standard approach, the dissipation matrix of the preconditioned numerical flux function possesses an eigenvalue growing like M-2 as M tends to zero, thus causing the diminishment of the stability region of the explicit scheme. Thereby, we present statements for both the standard preconditioner used by Guillard and Viozat [4] and the more general one due to Turkel [21]. The theoretical results are after wards confirmed by numerical experiments.