Soberania e acumulação de capital: uma análise crítica de Hugo Grotius, Pasquale Mancini e Hans Kelsen

A soberania já foi conceituada de diversos modos ao longo da história. Apesar disso, não deixou de ser a categoria mais elementar do direito internacional; expressando o fundamento de atuação dos Estados, foi através da soberania que o direito internacional se desenvolveu do Século XVII até os dias de hoje. Isso evidencia uma distinção entre o conteúdo da soberania, quer dizer, o seu modo de manifestação, o seu conceito, que se altera em cada período histórico, de um lado, e, do outro, a forma jurídica internacional expressa pela soberania, que se mantém intacta e que existe independentemente do conteúdo que lhe é dado, quer dizer, o lugar que ela ocupa no direito internacional. Através da análise do conceito de soberania fornecido por três autores clássicos de diferentes períodos históricos Hugo Grotius, Pasquale Mancini e Hans Kelsen o presente trabalho tem por objetivo demonstrar o caráter ideológico de cada teoria e, conseqüentemente, sua inexatidão. Para fazê-lo, foi adotado o método materialista dialético, através do qual a produção de idéias por parte do homem deve ser observada nos limites das suas condições de existência e as idéias produzidas como um reflexo consciente do mundo real. Cuida-se, assim, de observar o direito de superioridade afirmado por Grotius nos limites das condições de existência humana que se alteravam com a transição do feudalismo para capitalismo, e extrai-se o seu sentido da luta entre a Igreja e os monarcas que iam centralizando sob si o poder. Da mesma forma, observa-se o direito de nacionalidade de Mancini sob as condições de existência propiciadas pelo amadurecimento das classes sociais do capitalismo na Europa Ocidental como fruto da Revolução Industrial, extraindo-se seu sentido das lutas revolucionárias por libertação nacional que ali se desenrolavam. O caráter essencialmente limitado da soberania de Kelsen, enfim, será observado no contexto da passagem do capitalismo para sua época imperialista, como um reflexo consciente dos desenvolvimentos experimentados pelo direito internacional no fim do Século XIX e início do Século XX, após a Primeira Guerra Mundial. Assim, além de demonstrar o caráter ideológico e a inexatidão dos conceitos mencionados, busca-se demonstrar que o conteúdo da soberania em cada período histórico analisado encontra sua razão de ser na correspondente fase de desenvolvimento do capitalismo e que a forma jurídica soberania, isto é, o lugar que ela ocupa no direito internacional, é determinado pela necessidade do capitalismo de um instrumento de força que assegure a acumulação de capital, o Estado soberano.

Experimental study on inertial effects in liquid-solid flows

This thesis presents experimental measurements of the rheological behavior of liquid-solid mixtures at moderate Reynolds (defined by the shear rate and particle diameter) and Stokes numbers, ranging from 3 ≤ Re ≤ 1.6 × 10³ and 0.4 ≤ St ≤ 195. The experiments use a specifically designed Couette cylindrical rheometer that allows for probing the transition from transporting a pure liquid to transporting a dense suspension of particles. Measurements of the shear stress are presented for a wide range of particle concentration (10 to 60% in volume) and for particle to fluid density ratio between 1 and 1.05. The effective relative viscosity exhibits a strong dependence on the solid fraction for all density ratios tested. For density ratio of 1 the effective viscosity increases with Stokes number (St) for volume fractions (φ) lower than 40% and becomes constant for higher φ. When the particles are denser than the liquid, the effective viscosity shows a stronger dependance on St. An analysis of the particle resuspension for the case with a density ratio of 1.05 is presented and used to predict the local volume fraction where the shear stress measurements take place. When the local volume fraction is considered, the effective viscosity for settling and no settling particles is consistent, indicating that the effective viscosity is independent of differences in density between the solid and liquid phase. Shear stress measurements of pure fluids (no particles) were performed using the same rheometer, and a deviation from laminar behavior is observed for gap Reynolds numbers above 4× 10³, indicating the presence of hydrodynamic instabilities associated with the rotation of the outer cylinder. The increase on the effective viscosity with Stokes numbers observed for mixtures with φ ≤ 30% appears to be affected by such hydrodynamic instabilities. The effective viscosity for the current experiments is considerably higher than the one reported in non-inertial suspensions.

El Venture capital como fuente de financiación del proceso emprendedor

En los últimos años la financiación de empresas de nueva creación se ha convertido en uno de los principales obstáculos para los emprendedores a la hora de poner en marcha sus ideas de negocio. La difícil situación económico-financiera actual y las características particulares de estas empresas hacen que la financiación bancaria sea una alternativa más bien inviable. Este trabajo pretende explorar otras fuentes de financiación alternativas a la bancaria que se puedan ajustar más a las características de las empresas de reciente creación y, más en concreto, estudiar el papel que ha jugado y juega el venture capital como fuente de financiación, analizando aspectos teóricos del mismo y su evolución en los últimos años para, posteriormente, desarrollar un estudio empírico que analice las características y resultados obtenidos por las empresas financiadas por venture capital en España en los últimos años.

Impacto solvencia II en un seguro de vida

La actividad aseguradora supone la transferencia de riesgos del asegurado al asegurador. El asegurador se compromete al pago de una prestación si el riesgo se realiza. Se produce un cambio en el ciclo productivo. El asegurador vende una cobertura sin conocer el momento y el coste exacto de dicha cobertura. Esta particularidad de la actividad aseguradora explica la necesidad para una entidad aseguradora de ser solvente en cada momento y ante cualquier imprevisto. Por ello, la solvencia de las entidades aseguradoras es un aspecto que se ha ido recogiendo en las distintas normativas que han regulado la actividad aseguradora y al que se ha ido dando cada vez más importancia. Actualmente la legislación vigente en materia de solvencia de las aseguradoras esta regulada por la directiva europea Solvencia I. Esta directiva establece dos conceptos para garantizar la solvencia: las provisiones técnicas y el margen de solvencia. Las provisiones técnicas son las calculadas para garantizar la solvencia estática de la compañía, es decir aquella que hace frente, en un instante temporal determinado, a los compromisos asumidos por la entidad. El margen de solvencia se destina a cubrir la solvencia dinámica, aquella que hace referencia a eventos futuros que puedan afectar la capacidad del asegurador. Sin embargo en una corriente de gestión global del riesgo en la que el sector bancario ya se había adelantado al sector asegurador con la normativa Basilea II, se decidió iniciar un proyecto europeo de reforma de Solvencia I y en noviembre del 2009 se adoptó la directiva 2009/138/CE del parlamento europeo y del consejo, sobre el seguro de vida, el acceso a la actividad de seguro y de reaseguro y su ejercicio mas conocida como Solvencia II. Esta directiva supone un profundo cambio en las reglas actuales de solvencia para las entidades aseguradoras. Este cambio persigue el objetivo de establecer un marco regulador común a nivel europeo que sea más adaptado al perfil de riesgo de cada entidad aseguradora. Esta nueva directiva define dos niveles distintos de capital: el SCR (requerimiento estándar de capital de solvencia) y el MCR (requerimiento mínimo de capital). Para el calculo del SCR se ha establecido que el asegurador tendrá la libertad de elegir entre dos modelos. Un modelo estándar propuesto por la Autoridad Europea de Seguros y Pensiones de Jubilación (EIOPA por sus siglas en inglés), que permitirá un calculo simple, y un modelo interno desarrollado por la propia entidad que deberá ser aprobado por las autoridades competentes. También se contempla la posibilidad de utilizar un modelo mixto que combine ambos, el estándar y el interno. Para el desarrollo del modelo estándar se han realizado una serie de estudios de impacto cuantitativos (QIS). El último estudio (QIS 5) ha sido el que ha planteado de forma más precisa el cálculo del SCR. Plantea unos shocks que se deberán de aplicar al balance de la entidad con el objetivo de estresarlo, y en base a los resultados obtenidos constituir el SCR. El objetivo de este trabajo es realizar una síntesis de las especificaciones técnicas del QIS5 para los seguros de vida y realizar una aplicación práctica para un seguro de vida mixto puro. En la aplicación práctica se determinarán los flujos de caja asociados a este producto para calcular su mejor estimación (Best estimate). Posteriormente se determinará el SCR aplicando los shocks para los riesgos de mortalidad, rescates y gastos. Por último, calcularemos el margen de riesgo asociado al SCR. Terminaremos el presente TFG con unas conclusiones, la bibliografía empleada así como un anexo con las tablas empleadas.

Effects of density differences on lateral mixing in open-channel flows

This study investigates lateral mixing of tracer fluids in turbulent open-channel flows when the tracer and ambient fluids have different densities. Longitudinal dispersion in flows with longitudinal density gradients is investigated also.

Lateral mixing was studied in a laboratory flume by introducing fluid tracers at the ambient flow velocity continuously and uniformly across a fraction of the flume width and over the entire depth of the ambient flow. Fluid samples were taken to obtain concentration distributions in cross-sections at various distances, x, downstream from the tracer source. The data were used to calculate variances of the lateral distributions of the depth-averaged concentration. When there was a difference in density between the tracer and the ambient fluids, lateral mixing close to the source was enhanced by density-induced secondary flows; however, far downstream where the density gradients were small, lateral mixing rates were independent of the initial density difference. A dimensional analysis of the problem and the data show that the normalized variance is a function of only three dimensionless numbers, which represent: (1) the x-coordinate, (2) the source width, and (3) the buoyancy flux from the source.

A simplified set of equations of motion for a fluid with a horizontal density gradient was integrated to give an expression for the density-induced velocity distribution. The dispersion coefficient due to this velocity distribution was also obtained. Using this dispersion coefficient in an analysis for predicting lateral mixing rates in the experiments of this investigation gave only qualitative agreement with the data. However, predicted longitudinal salinity distributions in an idealized laboratory estuary agree well with published data.

Transferência de renda e capital portador de juros: uma insidiosa captura

Esta dissertação tem como objeto de estudo a relação entre capital portador de juros e programas de transferência de renda na atualidade. O objetivo pretendido é a análise da dinâmica de organização desta forma de capital e seus desdobramentos na contemporaneidade, bem como os impactos e determinações impostas às políticas sociais em tempos de financeirização do capital. Partimos da hipótese de que os programas de transferência de renda contribuem para o processo de contra-reforma das políticas sociais, tanto pela focalização preconizada como pela priorização orçamentária, em detrimento dos demais programas e projetos da assistência social, além de permitirem a remuneração do capital portador de juros por meio dos recursos que destinam às instituições bancárias. A pesquisa realizada utilizou-se de análise documental e teórica com base na tradição marxista, buscando analisar criticamente as configurações das políticas sociais na atualidade e o papel das transferências de renda. Buscamos ainda analisar o orçamento público no âmbito federal referente à Seguridade Social e, em particular, aos programas de transferência de renda no âmbito da Assistência Social. Escolhemos estudar o orçamento da Renda Mensal Vitalícia, o Benefício de Prestação Continuada e o Programa Bolsa-Família, entre os anos de 2006 e 2009, analisando os recursos que estes destinam às instituições bancárias que operacionalizam o repasse dos benefícios. O resultado da pesquisa demonstrou que os programas de transferência de renda são estratégias de contra-reformar as políticas sociais ao incentivar o processo de assistencialização da Seguridade Social visto que apresentam um aumento contínuo e substancial no âmbito orçamentário e ao operarem com a seletividade do atendimento aos mais pobres na contramão dos princípios fundamentais presentes no texto constitucional. São ainda mecanismos de alimentação do capital portador de juros ao repassarem consideráveis somas de recursos para as instituições bancárias e inserirem a classe trabalhadora pobre no mundo das finanças.

Entrainment of fine sediments by turbulent flows

A study was made of the means by which turbulent flows entrain sediment grains from alluvial stream beds. Entrainment was considered to include both the initiation of sediment motion and the suspension of grains by the flow. Observations of grain motion induced by turbulent flows led to the formulation of an entrainment hypothesis. It was based on the concept of turbulent eddies disrupting the viscous sublayer and impinging directly onto the grain surface. It is suggested that entrainment results from the interaction between fluid elements within an eddy and the sediment grains.

A pulsating jet was used to simulate the flow conditions in a turbulent boundary layer. Evidence is presented to establish the validity of this representation. Experiments were made to determine the dependence of jet strength, defined below, upon sediment and fluid properties. For a given sediment and fluid, and fixed jet geometry there were two critical values of jet strength: one at which grains started to roll across the bed, and one at which grains were projected up from the bed. The jet strength K, is a function of the pulse frequency, ω, and the pulse amplitude, A, defined by

K = Aω^-s

Where s is the slope of a plot of log A against log ω. Pulse amplitude is equal to the volume of fluid ejected at each pulse divided by the cross sectional area of the jet tube.

Dimensional analysis was used to determine the parameters by which the data from the experiments could be correlated. Based on this, a method was devised for computing the pulse amplitude and frequency necessary either to move or project grains from the bed for any specified fluid and sediment combination.

Experiments made in a laboratory flume with a turbulent flow over a sediment bed are described. Dye injection was used to show the presence, in a turbulent boundary layer, of two important aspects of the pulsating jet model and the impinging eddy hypothesis. These were the intermittent nature of the sublayer and the presence of velocities with vertical components adjacent to the sediment bed.

A discussion of flow conditions, and the resultant grain motion, that occurred over sediment beds of different form is given. The observed effects of the sediment and fluid interaction are explained, in each case, in terms of the entrainment hypothesis.

The study does not suggest that the proposed entrainment mechanism is the only one by which grains can be entrained. However, in the writer’s opinion, the evidence presented strongly suggests that the impingement of turbulent eddies onto a sediment bed plays a dominant role in the process.

Particle fluid mechanics in shear flows, acoustic waves, and shock waves

Three different categories of flow problems of a fluid containing small particles are being considered here. They are: (i) a fluid containing small, non-reacting particles (Parts I and II); (ii) a fluid containing reacting particles (Parts III and IV); and (iii) a fluid containing particles of two distinct sizes with collisions between two groups of particles (Part V).

Part I

A numerical solution is obtained for a fluid containing small particles flowing over an infinite disc rotating at a constant angular velocity. It is a boundary layer type flow, and the boundary layer thickness for the mixture is estimated. For large Reynolds number, the solution suggests the boundary layer approximation of a fluid-particle mixture by assuming W = W_p. The error introduced is consistent with the Prandtl’s boundary layer approximation. Outside the boundary layer, the flow field has to satisfy the “inviscid equation” in which the viscous stress terms are absent while the drag force between the particle cloud and the fluid is still important. Increase of particle concentration reduces the boundary layer thickness and the amount of mixture being transported outwardly is reduced. A new parameter, β = 1/Ω τ_v, is introduced which is also proportional to μ. The secondary flow of the particle cloud depends very much on β. For small values of β, the particle cloud velocity attains its maximum value on the surface of the disc, and for infinitely large values of β, both the radial and axial particle velocity components vanish on the surface of the disc.

Part II

The “inviscid” equation for a gas-particle mixture is linearized to describe the flow over a wavy wall. Corresponding to the Prandtl-Glauert equation for pure gas, a fourth order partial differential equation in terms of the velocity potential ϕ is obtained for the mixture. The solution is obtained for the flow over a periodic wavy wall. For equilibrium flows where λ_v and λ_T approach zero and frozen flows in which λ_v and λ_T become infinitely large, the flow problem is basically similar to that obtained by Ackeret for a pure gas. For finite values of λ_v and λ_T, all quantities except v are not in phase with the wavy wall. Thus the drag coefficient C_D is present even in the subsonic case, and similarly, all quantities decay exponentially for supersonic flows. The phase shift and the attenuation factor increase for increasing particle concentration.

Part III

Using the boundary layer approximation, the initial development of the combustion zone between the laminar mixing of two parallel streams of oxidizing agent and small, solid, combustible particles suspended in an inert gas is investigated. For the special case when the two streams are moving at the same speed, a Green’s function exists for the differential equations describing first order gas temperature and oxidizer concentration. Solutions in terms of error functions and exponential integrals are obtained. Reactions occur within a relatively thin region of the order of λ_D. Thus, it seems advantageous in the general study of two-dimensional laminar flame problems to introduce a chemical boundary layer of thickness λ_D within which reactions take place. Outside this chemical boundary layer, the flow field corresponds to the ordinary fluid dynamics without chemical reaction.

Part IV

The shock wave structure in a condensing medium of small liquid droplets suspended in a homogeneous gas-vapor mixture consists of the conventional compressive wave followed by a relaxation region in which the particle cloud and gas mixture attain momentum and thermal equilibrium. Immediately following the compressive wave, the partial pressure corresponding to the vapor concentration in the gas mixture is higher than the vapor pressure of the liquid droplets and condensation sets in. Farther downstream of the shock, evaporation appears when the particle temperature is raised by the hot surrounding gas mixture. The thickness of the condensation region depends very much on the latent heat. For relatively high latent heat, the condensation zone is small compared with Ʌ_D.

For solid particles suspended initially in an inert gas, the relaxation zone immediately following the compression wave consists of a region where the particle temperature is first being raised to its melting point. When the particles are totally melted as the particle temperature is further increased, evaporation of the particles also plays a role.

The equilibrium condition downstream of the shock can be calculated and is independent of the model of the particle-gas mixture interaction.

Part V

For a gas containing particles of two distinct sizes and satisfying certain conditions, momentum transfer due to collisions between the two groups of particles can be taken into consideration using the classical elastic spherical ball model. Both in the relatively simple problem of normal shock wave and the perturbation solutions for the nozzle flow, the transfer of momentum due to collisions which decreases the velocity difference between the two groups of particles is clearly demonstrated. The difference in temperature as compared with the collisionless case is quite negligible.

I. Stokes flow past a thin screen. II. Viscous flows past porous bodies of finite size

Part I

The slow, viscous flow past a thin screen is analyzed based on Stokes equations. The problem is reduced to an associated electric potential problem as introduced by Roscoe. Alternatively, the problem is formulated in terms of a Stokeslet distribution, which turns out to be equivalent to the first approach.

Special interest is directed towards the solution of the Stokes flow past a circular annulus. A "Stokeslet" formulation is used in this analysis. The problem is finally reduced to solving a Fredholm integral equation of the second kind. Numerical data for the drag coefficient and the mean velocity through the hole of the annulus are obtained.

Stokes flow past a circular screen with numerous holes is also attempted by assuming a set of approximate boundary conditions. An "electric potential" formulation is used, and the problem is also reduced to solving a Fredholm integral equation of the second kind. Drag coefficient and mean velocity through the screen are computed.

Part II

The purpose of this investigation is to formulate correctly a set of boundary conditions to be prescribed at the interface between a viscous flow region and a porous medium so that the problem of a viscous flow past a porous body can be solved.

General macroscopic equations of motion for flow through porous media are first derived by averaging Stokes equations over a volume element of the medium. These equations, including viscous stresses for the description, are more general than Darcy's law. They reduce to Darcy's law when the Darcy number becomes extremely small.

The interface boundary conditions of the first kind are then formulated with respect to the general macroscopic equations applied within the porous region. An application of such equations and boundary conditions to a Poiseuille shear flow problem demonstrates that there usually exists a thin interface layer immediately inside the porous medium in which the tangential velocity varies exponentially and Darcy's law does not apply.

With Darcy's law assumed within the porous region, interface boundary conditions of the second kind are established which relate the flow variables across the interface layer. The primary feature is a jump condition on the tangential velocity, which is found to be directly proportional to the normal gradient of the tangential velocity immediately outside the porous medium. This is in agreement with the experimental results of Beavers, et al.

The derived boundary conditions are applied in the solutions of two other problems: (1) Viscous flow between a rotating solid cylinder and a stationary porous cylinder, and (2) Stokes flow past a porous sphere.