Nonlinear saturation of electrostatic waves: mobile ions modify trapping scaling

The amplitude equation for an unstable electrostatic wave in a multi-species Vlasov plasma has been derived. The dynamics of the mode amplitude $\rho(t)$ is studied using an expansion in $\rho$; in particular, in the limit $\gamma\rightarrow0^+$, the singularities in the expansion coefficients are analyzed to predict the asymptotic dependence of the electric field on the linear growth rate $\gamma$. Generically $|E_k|\sim \gamma^{5/2}$, as $\gamma\rightarrow0^+$, but in the limit of infinite ion mass or for instabilities in reflection-symmetric systems due to real eigenvalues the more familiar trapping scaling $|E_k|\sim \gamma^{2}$ is predicted.Comment: 13 pages (Latex/RevTex), 4 postscript encapsulated figures which are included using the utility "uufiles". They should be automatically included with the text when it is downloaded. Figures also available in hard copy from the authors ([email protected]

Algebro-Geometric Solutions of the Boussinesq Hierarchy

We continue a recently developed systematic approach to the Bousinesq (Bsq) hierarchy and its algebro-geometric solutions. Our formalism includes a recursive construction of Lax pairs and establishes associated Burchnall-Chaundy curves, Baker-Akhiezer functions and Dubrovin-type equations for analogs of Dirichlet and Neumann divisors. The principal aim of this paper is a detailed theta function representation of all algebro-geometric quasi-periodic solutions and related quantities of the Bsq hierarchy.Comment: LaTeX, 48 page

Hipertensão arterial sistémica em idade pediátrica

The definition of hypertension (HT) in the pediatric age group is based on the normal distribution of blood pressure (BP) in healthy children. Normal BP is defined as being below the 90th percentile for gender, age and height, and hypertension as equal to or higher than the 95th percentile on at least three separate occasions. If the values are above the 90th percentile but below the 95th percentile, the child should be considered prehypertensive. Ambulatory BP monitoring is useful in the assessment of BP levels in the young. P values in children and adolescents have creased in the last decade, in parallel with increases in body mass index, and HT now has a prevalence of 2-5%. Obesity in childhood and adolescence is one of the main predictors of HT in adulthood, but it is also associated with other cardiovascular risk factors such as dyslipidemia, abnormal glucose metabolism, insulin resistance, inflammation and impaired vascular function. Left ventricular hypertrophy is the most prominent evidence of target organ damage caused by hypertension in children and adolescents. The goal for antihypertensive treatment is to reduce BP below the 95th percentile. Weight control, with regular physical activity and dietary changes, is the primary therapy for obesity-related hypertension. Weight loss decreases not only BP but also other cardiovascular risk factors. The indications for use of antihypertensive drugs are: symptomatic hypertension, secondary hypertension, established hypertensive target organ damage, stage 2 hypertension and failure of nonpharmacologic measures

On scattering of solitons for the Klein-Gordon equation coupled to a particle

We establish the long time soliton asymptotics for the translation invariant nonlinear system consisting of the Klein-Gordon equation coupled to a charged relativistic particle. The coupled system has a six dimensional invariant manifold of the soliton solutions. We show that in the large time approximation any finite energy solution, with the initial state close to the solitary manifold, is a sum of a soliton and a dispersive wave which is a solution of the free Klein-Gordon equation. It is assumed that the charge density satisfies the Wiener condition which is a version of the ``Fermi Golden Rule''. The proof is based on an extension of the general strategy introduced by Soffer and Weinstein, Buslaev and Perelman, and others: symplectic projection in Hilbert space onto the solitary manifold, modulation equations for the parameters of the projection, and decay of the transversal component.Comment: 47 pages, 2 figure

Hacia una política posfundacional: reconsideraciones en torno de la revolución, la fundación y el poder en Hannah Arendt

En las páginas siguientes nos adentraremos en el problema de la fundación en Sobre la revolucion siguiendo dos hipótesis de lectura, por un lado, que la tematización de la fundación en Arendt da lugar a lo que denominamos, siguiendo a Oliver Marchart (2009), una política posfundacional, que se sustenta en fundamentos contingentes pero a la vez de relativa estabilidad. A partir de esto, indagamos en torno del acto constituyente y del tipo de fundación en que está pensando Arendt, así como en sus reverberaciones para una crítica de la democracia representativa. Por otro lado, en torno de la fundación sostenemos que es posible encontrar dos conceptualizaciones del poder -el poder de reunión y el poder fundacional-, que resultan complementarias pero irreductibles al poder discursivo tal y como es presentado en La condición humana. El poder que surge vinculado con la fundación es un poder atravesado por la conflictividad y la violencia, lo que nos permitirá desmarcar la concepción de Arendt de la posición de Habermas (2000), a la vez que reconsiderar la política y sus vínculos con el poder y la violencia.Facultad de Humanidades y Ciencias de la Educació

Hacia una política posfundacional: reconsideraciones en torno de la revolución, la fundación y el poder en Hannah Arendt

En las páginas siguientes nos adentraremos en el problema de la fundación en Sobre la revolucion siguiendo dos hipótesis de lectura, por un lado, que la tematización de la fundación en Arendt da lugar a lo que denominamos, siguiendo a Oliver Marchart (2009), una política posfundacional, que se sustenta en fundamentos contingentes pero a la vez de relativa estabilidad. A partir de esto, indagamos en torno del acto constituyente y del tipo de fundación en que está pensando Arendt, así como en sus reverberaciones para una crítica de la democracia representativa. Por otro lado, en torno de la fundación sostenemos que es posible encontrar dos conceptualizaciones del poder -el poder de reunión y el poder fundacional-, que resultan complementarias pero irreductibles al poder discursivo tal y como es presentado en La condición humana. El poder que surge vinculado con la fundación es un poder atravesado por la conflictividad y la violencia, lo que nos permitirá desmarcar la concepción de Arendt de la posición de Habermas (2000), a la vez que reconsiderar la política y sus vínculos con el poder y la violencia.Facultad de Humanidades y Ciencias de la Educació

A dimension-breaking phenomenon for water waves with weak surface tension

It is well known that the water-wave problem with weak surface tension has small-amplitude line solitary-wave solutions which to leading order are described by the nonlinear Schr\"odinger equation. The present paper contains an existence theory for three-dimensional periodically modulated solitary-wave solutions which have a solitary-wave profile in the direction of propagation and are periodic in the transverse direction; they emanate from the line solitary waves in a dimension-breaking bifurcation. In addition, it is shown that the line solitary waves are linearly unstable to long-wavelength transverse perturbations. The key to these results is a formulation of the water wave problem as an evolutionary system in which the transverse horizontal variable plays the role of time, a careful study of the purely imaginary spectrum of the operator obtained by linearising the evolutionary system at a line solitary wave, and an application of an infinite-dimensional version of the classical Lyapunov centre theorem.Comment: The final publication is available at Springer via http://dx.doi.org/10.1007/s00205-015-0941-

The scaling attractor and ultimate dynamics for Smoluchowski's coagulation equations

We describe a basic framework for studying dynamic scaling that has roots in dynamical systems and probability theory. Within this framework, we study Smoluchowski's coagulation equation for the three simplest rate kernels $K(x,y)=2$, $x+y$ and $xy$. In another work, we classified all self-similar solutions and all universality classes (domains of attraction) for scaling limits under weak convergence (Comm. Pure Appl. Math 57 (2004)1197-1232). Here we add to this a complete description of the set of all limit points of solutions modulo scaling (the scaling attractor) and the dynamics on this limit set (the ultimate dynamics). The main tool is Bertoin's L\'{e}vy-Khintchine representation formula for eternal solutions of Smoluchowski's equation (Adv. Appl. Prob. 12 (2002) 547--64). This representation linearizes the dynamics on the scaling attractor, revealing these dynamics to be conjugate to a continuous dilation, and chaotic in a classical sense. Furthermore, our study of scaling limits explains how Smoluchowski dynamics ``compactifies'' in a natural way that accounts for clusters of zero and infinite size (dust and gel)

Anomalous Dynamic Scaling in Locally-Conserved Coarsening of Fractal Clusters

We report two-dimensional phase-field simulations of locally-conserved coarsening dynamics of random fractal clusters with fractal dimension D=1.7 and 1.5. The correlation function, cluster perimeter and solute mass are measured as functions of time. Analyzing the correlation function dynamics, we identify two different time-dependent length scales that exhibit power laws in time. The exponents of these power laws are independent of D, one of them is apparently the classic exponent 1/3. The solute mass versus time exhibits dynamic scaling with a D-dependent exponent, in agreement with a simple scaling theory.Comment: 5 pages, 4 figure

Perceptions and evaluations of front-line health workers regarding the Brazilian National Program for Improving Access and Quality to Primary Care (PMAQ): a mixed-method approach

Although it is well known that a successful implementation depends on the front-liners’ knowledge and participation, as well as on the organizational capacity of the institutions involved, we still know little about how front-line health workers have been involved in the implementation of the Brazilian National Program for Improving Access and Quality to Primary Care (PMAQ). This paper develops a contingent mixed-method approach to explore the perceptions of front-line health workers - managers, nurses, community health workers, and doctors - regarding the PMAQ (2nd round), and their evaluations concerning health unit organizational capacity. The research is guided by three relevant inter-related concepts from implementation theory: policy knowledge, participation, and organizational capacity. One hundred and twenty-seven health workers from 12 primary health care units in Goiânia, Goiás State, Brazil, answered semi-structured questionnaires, seeking to collect data on reasons for adherence, forms of participation, perceived impact (open-ended questions), and evaluation of organizational capacity (score between 0-10). Content analyses of qualitative data enabled us to categorize the variables “level of perceived impact of PMAQ” and “reasons for adhering to PMAQ”. The calculation and aggregation of the means for the scores given for organizational capacity enabled us to classify distinct levels of organizational capacity. We finally integrated both variables (Perceived-Impact and Organizational-Capacity) through cross-tabulation and the narrative. Results show that nurses are the main type of professional participating. The low organizational capacity and little policy knowledge affected workers participation in and their perceptions of the PMAQ