Symmetry, singularities and integrability in complex dynamics II: Rescaling and time-translation in two-dimensional systems

The explicit integrability of second order ordinary differential equations invariant under time-translation and rescaling is investigated. Quadratic systems generated from the linearisable version of this class of equations are analysed to determine therelationship between the Painlev\'e and singularity properties of the different systems. The transformation contains a parameter and for critical values, intimately related to the possession of the Painlev\'e Property in the parent second order equation, one finds a difference from the generic behaviour. This study is a prelude to a full discussion of the class of transformations which preserve the Painlev\'e Property in the construction of quadratic systems from scalar nonlinear odes invariant under time translation and rescaling.Comment: 25 pp, latex. To appear in J.Math.Anal.App

Too expensive to treat? Non-treatment decisions at the margins of viability

This article seeks to challenge the assumption that it is legitimate to consider the costs of premature babies' future social and educational needs when deciding what treatment, if any, to provide in the neonatal intensive care unit (NICU) . It questions the elision that is made between the claim that a particular treatment is insufficiently cost-effective and the claim that a person will be a burden on the state in the future. It discusses a series of common misunderstandings about how treatment decisions are taken in the NICU and concludes by suggesting that the claim that premature babies are too expensive to treat may depend upon regarding a premature infant as if she were not yet a person, with rights and interests of her own

Limiting law: art in the street and street in the art

Conventional legal responses to street art have tended to characterize it as a problem that is best dealt with through criminal law sanctions. This is not necessarily a problem for street artists who have been keen to situate understandings of their work outside of the law. But attitudes are changing. Street art is increasingly seen as having commercial value, enhancing the cityscape, creating new local art markets, attracting tourists, and contributing to the gentrification of an area with the result that conventional ways of conceiving of street art have begun to pose new challenges to concepts of crime and property. Drawing on an observational study in London, this article proposes a new theorization of the legal problems posed by street art that pays close attention to the sensual experience of encountering it in the city and to street art as performance rather than artefact

The ownership of time: culture, property and social theory

The main argument of this thesis is that the future-oriented vision that characterizes modernity has, in recent years, become inverted into an obsession with the past, an obsession that is played out using the discourses of "ownership". The argument is developed by drawing a parallel between the question of time and place as it has been addressed in social theoretical discourses and (increasing) public concerns with owning the past - a past that is accessed and (more importantly) appropriated by means of claims to the ownership of ancient objects. The argument looks at two specific cases in which ownership of objects is translated into claims for ownership of the past: the Parthenon Marbles case and the Kennewick Man case. First, the argument engages in legal analysis of the property claims set out in these cases. Second, it analyses these legal claims by reference to the theories of Friedrich Nietzsche, Michel Foucault, and Frantz Fanon (among others) in order to question the meaning of these legal conflicts. What light do current social-theoretical discussions shed on the proliferation of cultural property and cultural heritage. Arguably, claims that turn on ownership of these sorts of objects themselves express a deep discomfort with the present understanding of modern society's location in time. The thesis concludes by suggesting that this obsession with the past is a reaction to the modernist obsession with the future, and that the lack of "place" that is so characteristic of modernity is also experienced as a lack of "time" for human flourishing. The proliferation of cultural property and cultural heritage cases and issues in law, and the increasing number of new museums, can be traced to these interconnecting absences, which discourses of ownership attempt to overcome

Implantação de modelo de previsão de demanda em uma microempresa de vestuário

O presente artigo propõe a implantação de um modelo de previsão de demanda baseado em séries temporais. O estudo foi realizado em uma microempresa de vestuário com venda de produtos próprios e de terceiros, totalizando aproximadamente 8 mil itens. A metodologia proposta consistiu na coleta e classificação dos dados, seguida da escolha do modelo mais adequado e sua aplicação e avaliação dos resultados. A escolha do modelo considerou a relação entre a acurácia das previsões e a simplicidade de aplicação. O modelo utilizado é uma variante do método de Holt-winters. O modelo proposto apresentou erros na previsão bastante variados entre os grupos, com MPE a partir de 2% e MAPE a partir de 12%, para alguns dos grupos mais representativos. A melhoria da gestão de estoques e de compras na empresa são resultados esperados com a sua aplicação, com consequente diminuição de seus custos operacionais.This article proposes the implementation of a time series forecasting model. The study was performed in a small clothing company, which sells its own products as well as third part ones, totalizing eight thousand items. The indicated methodology consists in data collection and classification, followed by the choice of the most suitable model and its application and results evaluation. The choice for the model considered the relation between the accuracy of the predictions and the simplicity of the application. The model used is a variant of the Holt-Winters method. The proposed model presented several different errors in the forecast amongst the groups, with a MPE from 2% and a MAPE from 12%, for some of the most representative groups. The improvement in the inventory management and procurement in the company are the expected results with the application of the model, with consequential minimization of operational costs

Quasi-exactly solvable cases of the N-dimensional symmetric quartic anharmonic oscillator

The O(N) invariant quartic anharmonic oscillator is shown to be exactly solvable if the interaction parameter satisfies special conditions. The problem is directly related to that of a quantum double well anharmonic oscillator in an external field. A finite dimensional matrix equation for the problem is constructed explicitly, along with analytical expressions for some excited states in the system. The corresponding Niven equations for determining the polynomial solutions for the problem are given.Comment: 7 pages, RevTeX4. A discussion on the N=1 case has been added with the boundary condition properly treate

Quasi-Exactly Solvable Potentials with Two Known Eigenstates

A new supersymmetry method for the generation of the quasi-exactly solvable (QES) potentials with two known eigenstates is proposed. Using this method we obtained new QES potentials for which we found in explicit form the energy levels and wave functions of the ground state and first excited state.Comment: 13 pages, Latex, replaced by revised versio

Pathophysiology of Resistant Hypertension: The Role of Sympathetic Nervous System

Resistant hypertension (RH) is a powerful risk factor for cardiovascular morbidity and mortality. Among the characteristics of patients with RH, obesity, obstructive sleep apnea, and aldosterone excess are covering a great area of the mosaic of RH phenotype. Increased sympathetic nervous system (SNS) activity is present in all these underlying conditions, supporting its crucial role in the pathophysiology of antihypertensive treatment resistance. Current clinical and experimental knowledge points towards an impact of several factors on SNS activation, namely, insulin resistance, adipokines, endothelial dysfunction, cyclic intermittent hypoxaemia, aldosterone effects on central nervous system, chemoreceptors, and baroreceptors dysregulation. The further investigation and understanding of the mechanisms leading to SNS activation could reveal novel therapeutic targets and expand our treatment options in the challenging management of RH

An unusual pattern of three major components of the cardiovascular system: multimodality imaging and review of the literature

INTRODUCTION: Coronary artery anomalies are found in 0.4% to 1.4% of patients who undergo coronary angiography. Anomalous origin of left coronary artery from the right sinus of Valsava is the rarest, with a reported prevalence of 0.02 –0.03% according to angiographic studies. CASE PRESENTATION: We present the rare case of a 42-year-old-man suffering from stable angina with unusual development of 3 major components of the cardiovascular system Coronary angiography revealed an anomalous origin of the left coronary artery from the ostium of the right coronary artery. Magnetic resonance angiography depicted an anomalous origin of the left common carotid artery from the innominate artery and an aneurysm of descending thoracic aorta. Coronary computed tomography angiography revealed the course of left coronary artery between aortic root and conus arteriosus at the level of the right ventricular outflow tract. In this report we attempt to highlight the rarity of this vascular anatomy. CONCLUSION: Anomalous origins of the coronary arteries are rare, but may cause myocardial ischemia and sudden death. Thus, their reliable identification is a matter of paramount importance possibly evaluating the effects of therapeutic intervention. Newer imaging modalities improve the illumination of vascular system anatomy, shedding light to diagnostic dilemmas that come up in daily medical practice