Nonlinear dynamics in ventricular fibrillation.

Electrogram recordings of ventricular fibrillation appear complex and possibly chaotic. However, sequences of beat-to-beat intervals obtained from these recordings are generally short, making it difficult to explicitly demonstrate nonlinear dynamics. Motivated by the work of Sugihara on atmospheric dynamics and the Durbin-Watson test for nonlinearity, we introduce a new statistical test that recovers significant dynamical patterns from smoothed lag plots. This test is used to show highly significant nonlinear dynamics in a stable canine model of ventricular fibrillation.

Role of oxidation in the neurotoxic effects of intrastriatal dopamine injections.

We have examined the biochemical and histological effects of high concentrations of dopamine (0.05-1.0 micromol) injected into the rat striatum. Twenty-four hours after such injections, the oxidation products of dopamine and dihydroxyphenylacetic acid were detected as both free and protein-bound cysteinyl dopamine and cysteinyl dihydroxyphenylacetic acid. Protein-bound cysteinyl catechols were increased 7- to 20-fold above control tissue levels. By 7 days postinjection, the protein-bound cysteinyl catechols were still detectable, although reduced in concentration, whereas the free forms could no longer be measured. Histological examination of striatum at 7 days revealed a central core of nonspecific damage including neuronal loss and gliosis. This core was surrounded by a region containing a marked reduction in tyrosine hydroxylase immunoreactivity but no apparent loss of serotonin or synaptophysin immunoreactivity. When dopamine was injected with an equimolar concentration of either ascorbic acid or glutathione, the formation of protein-bound cysteinyl catechols was greatly reduced. Moreover, the specific loss of tyrosine hydroxylase immunoreactivity associated with dopamine injections was no longer detectable, although the nonspecific changes in cytoarchitecture were still apparent. Thus, following its oxidation, dopamine in high concentrations binds to protein in the striatum, an event that is correlated with the specific loss of dopaminergic terminals. We suggest that the selective degeneration of dopamine neurons in Parkinson's disease may be caused by an imbalance between the oxidation of dopamine and the availability of antioxidant defenses.

Estrutura espacial urbana e mobilidade: o caso da Região Metropolitana de São Paulo

A metrópole de São Paulo é a maior e mais importante aglomeração urbana do Brasil e está entre as dez maiores áreas urbanas do mundo. No entanto, a forma como acessibilidade espacial ocorre gera um fardo para a população e para a atividade econômica. Este trabalho pretende contribuir para a discussão de como melhorar a acessibilidade na Região Metropolitana de São Paulo estudando as características e impactos de estruturas espaciais urbana, analisando criticamente a estrutura espacial da metrópole e proporcionando sugestões de melhorias a fim de proporcionar uma mobilidade mais sustentável. Os procedimentos metodológicos incluem uma revisão bibliográfica sobre o tema e uma caracterização da estrutura espacial da Região Metropolitana de São Paulo, considerando a alocação de população, alocação de empregos e os padrões de deslocamento para os modais individual, coletivo e não motorizado. Apresentamos um relato da evolução recente, com dados das pesquisas de origem e destino realizadas pelo Metrô em 1997 e 2007 e da pesquisa de mobilidade de 2012. Também realizamos uma caracterização mais aprofundada com os dados da pesquisa de 2007. As cidades se desenvolvem com base no trade-off entre proximidade e mobilidade: a fim de maximizar as possibilidades de interação, as pessoas e as empresas tendem a se localizar onde o deslocamento necessário para executar essas interações requer menos custos financeiros, perda de tempo e desconforto. Esse processo molda a alocação espacial de atividades, que define parcialmente os hábitos de transporte. A estrutura espacial urbana pode ser caracterizada por sua escala (padrões compacto ou disperso), arranjo de densidades (padrão disperso ou clusterizado) e arranjo de atividade (padrão monocêntrico ou policêntrico). Estruturas espaciais com padrão mais compacto apresentam menores distâncias de viagem, reduzindo o impacto ambiental das viagens e viabilizando o transporte não motorizado e coletivo, e levam a um uso mais eficiente da terra, menor custo de infraestrutura e maior equidade no acesso ao transporte. Já estruturas clusterizadas policêntricas são associadas com maior facilidade de acesso à terra. Existe um debate sobre a capacidade de estruturas policêntricas resultarem em uma aproximação generalizada de empregos e residências. A Região Metropolitana de São Paulo apresenta um padrão monocêntrico na escala metropolitana, com fortes movimentos pendulares da periferia para o centro expandido da iii capital. Durante o período de análise, foi observada uma realocação da população para áreas mais centrais da cidade e uma centralização dos empregos ainda mais forte, resultando no agravamento dos movimentos pendulares. Existe uma clara divisão modal por renda: as classes mais altas utilizam majoritariamente automóveis, enquanto as classes mais baixas utilizam majoritariamente transporte coletivo e não motorizado. Para o futuro, o novo plano diretor tem o mérito de caminhar na direção do desenvolvimento urbano orientado pelo transporte sustentável, porém os níveis de densidade máxima permitidos ainda são parecidos com o do plano anterior e a largura dos eixos de adensamento é restrita. Acreditamos ser vantajoso um aumento do adensamento em áreas próximas dos empregos; geração de polos de adensamento em áreas mais afastadas dos empregos, mas próximas das infraestruturas de transporte coletivo de alta velocidade, e desencorajamento do adensamento em áreas com baixa acessibilidade. Também é necessária uma gestão integrada dos transportes, provendo infraestrutura para viagens não motorizadas e viagens intermodais, e uma gestão dos impactos negativos do adensamento.

Tethered Monte Carlo: computing the effective potential without critical slowing down

We present Tethered Monte Carlo, a simple, general purpose method of computing the effective potential of the order parameter (Helmholtz free energy). This formalism is based on a new statistical ensemble, closely related to the micromagnetic one, but with an extended configuration space (through Creutz-like demons). Canonical averages for arbitrary values of the external magnetic field are computed without additional simulations. The method is put to work in the two-dimensional Ising model, where the existence of exact results enables us to perform high precision checks. A rather peculiar feature of our implementation, which employs a local Metropolis algorithm, is the total absence, within errors, of critical slowing down for magnetic observables. Indeed, high accuracy results are presented for lattices as large as L = 1024.

Tethered Monte Carlo: computing the effective potential without critical slowing down

We present Tethered Monte Carlo, a simple, general purpose method of computing the effective potential of the order parameter (Helmholtz free energy). This formalism is based on a new statistical ensemble, closely related to the micromagnetic one, but with an extended configuration space (through Creutz-like demons). Canonical averages for arbitrary values of the external magnetic field are computed without additional simulations. The method is put to work in the two-dimensional Ising model, where the existence of exact results enables us to perform high precision checks. A rather peculiar feature of our implementation, which employs a local Metropolis algorithm, is the total absence, within errors, of critical slowing down for magnetic observables. Indeed, high accuracy results are presented for lattices as large as L = 1024.

The representation of the world in national Arab news agencies: an exploration of (trans)national networks in the official Arab media

The purpose of this paper is to draw a map of the representation of the world and of Arab states as reflected by the countries of the region. To do so, we have analysed the news (4,093 news randomly collected on February and August 2005) produced by the governments of the Arab states through their national news agencies. Several regional and world maps had been constructed to show the official Arab representation of the World, the Arab countries conflict agenda, the persistence of colonial ties (with the European metropolis) and the emergence of new relationships (Asian countries). The representation of the world that appeared in the analysis focuses its interest on the USA, the war in Iraq, the Israel-Palestine conflict, the United Kingdom, France, and Iran. The Arab regional powers organise the flow of information (Saudi Arabia and Egypt) and the colonial past determines the current structure of communication (French-speaking bloc and English-speaking bloc).

Account with Harvard College, 1770-1771

The one page document records Harvard's debit account with Steward Hastings for nails and brads purchased between September 1770 and March 1771.

Receipt signed by James Winthrop, 1772 December 10

Handwritten receipt signed by James Winthrop acknowledging money received from the Steward, also signed by Steward Jonathan Hastings. A handwritten transcription of the Corporation vote on December 10, 1772 granting money for caring for the College Library since May 1, 1772, is signed by President Samuel Locke on other side of the document.

Glazier's report, [ca. 1765-1775]

On verso: S. Hastings, S. Kendal. This report outlines the glass needed for College buildings in the mid-18th century. Estimates include windows for Hollis, Massachusetts, and Harvard Halls and an unspecified College House.

Notes on cases in Boston, 1784-1790

Notes on various cases, including cases of burglary, debt, fraud, libel, receiving stolen goods, and one case of attempted murder of an infant by his mother.

Deed of sale, 1723 August 10

Deed between grantor John Hastings and grantee Andrew Bordman for the second lot in the second division on "Cambridge Rocks."

Deed of sale, 1723 August 10

Deed between grantor John Hastings and grantee Andrew Bordman for nine acres of property on "Cambridge Rocks."

Deed of sale, 1724 July 4

Deed between grantors Joseph Hastings and Daniel Hastings and grantee Andrew Bordman for property on Cambridge Rocks. The deed also includes the marks of Elizabeth Hastings and Abigail Hastings.

Bond, 1728/9 January 30

Handwritten bond of Andrew Bordman to John Hastings.

British Isles, 1818 (Raster Image)

This layer is a georeferenced raster image of the historic paper map entitled: Cary's reduction of his six sheet map of the British Isles : comprehending the whole of the turnpike roads : with the great rivers and the course of the different navigable canals, also the market and borough towns and villages adjoining the road : to which is added the actual distance from one market town to another ; with the exact admeasurement to each from the metropolis : drawn from the most recent surveys. It was published by J. Cary in 1818. Scale [ca. 1:424,000].The image inside the map neatline is georeferenced to the surface of the earth and fit to the Europe Lambert Conformal Conic coordinate system. All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, index maps, legends, or other information associated with the principal map. This map shows features such as drainage, cities and other human settlements, territorial boundaries, shoreline features, roads, and more. Relief shown by hachures. Includes inset: The Shetland Isles.This layer is part of a selection of digitally scanned and georeferenced historic maps from the Harvard Map Collection. These maps typically portray both natural and manmade features. The selection represents a range of originators, ground condition dates, scales, and map purposes.