Breathers as Metastable States for the Discrete NLS equation

We study metastable motions in weakly damped Hamiltonian systems. These are believed to inhibit the transport of energy through Hamiltonian, or nearly Hamiltonian, systems with many degrees of freedom. We investigate this question in a very simple model in which the breather solutions that are thought to be responsible for the metastable states can be computed perturbatively to an arbitrary order. Then, using a modulation hypothesis, we derive estimates for the rate at which the system drifts along this manifold of periodic orbits and verify the optimality of our estimates numerically.Comment: Corrected typos. Added Acknowledgmen

Culture et santé mentale en Haïti : une revue de littérature

Cet article passe en revue et résume l’ensemble de la littérature sur la santé mentale et les services de santé mentale en Haïti. Ce compte rendu a été rédigé à la suite du tremblement de terre qui a frappé Haïti en janvier 2010. Nous avons effectué des recherches dans Medline, Google Scholar et d’autres bases de données disponibles en vue de recueillir la littérature scientifique pertinente sur la santé mentale en Haïti. La consultation d’ouvrages de référence et de la littérature grise sur Haïti a complété les recherches. La première partie décrit les principales données historiques, économiques, sociologiques et anthropologiques qui permettent de comprendre sommairement Haïti et sa population. La démographie, la structure familiale, l’économie haïtienne et la religion y sont abordées. La deuxième partie est axée sur la santé mentale et les services de santé mentale. L’épidémiologie élémentaire des maladies mentales, les croyances au sujet des maladies mentales, les modèles explicatifs, les idiomes de détresse, les comportements de recherche d’aide, la configuration des services de santé mentale et l’étude des relations entre la religion et la santé mentale y sont examinés.This paper reviews and summarizes the available literature on Haitian mental health and mental health services. This review was conducted in light of the Haitian earthquake in January 2010. We searched Medline, Google Scholar and other available databases to gather scholarly literature relevant to mental health in Haiti. This was supplemented by consultation of key books and grey literature relevant to Haiti. The first part of the review describes historical, economic, sociological and anthropological factors essential to a basic understanding of Haiti and its people. This includes discussion of demography, family structure, Haitian economics and religion. The second part of the review focuses on mental health and mental health services. This includes a review of factors such as basic epidemiology of mental illness, common beliefs about mental illness, explanatory models, idioms of distress, help-seeking behavior, configuration of mental health services and the relationship between religion and mental health.Este artículo revisa y resume la literatura sobre la salud mental y los servicios de salud mental en Haití. Este informe fue redactado después del terremoto que sacudió a Haití en enero de 2010. Realizamos búsquedas en Medline, Google Scholar y otras bases de datos disponibles a fin de recopilar la literatura científica pertinente acerca de la salud mental en Haití. La investigación fue completada con obras de referencia y literatura gris acerca de Haití. La primera parte describe los principales datos históricos, económicos, sociológicos y antropológicos que permiten comprender someramente a Haití y a su población. Se abordan la demografía, la estructura familiar, la economía haitiana y la religión. La segunda parte se centra en la salud mental y los servicios de salud mental. Se examinan la epidemiología elemental de las enfermedades mentales, las creencias con respecto a las enfermedades mentales, los modelos explicativos, las expresiones de angustia, los comportamientos de búsqueda de ayuda, la configuración de los servicios de salud mental y el estudio de las relaciones entre la religión y la salud mental.Este artigo passa em revista e resume a literatura sobre a saúde mental e os serviços de saúde mental no Haiti. Este resumo foi redigido após o tremor de terra que atingiu o Haiti em janeiro de 2010. Realizamos pesquisas no Medline, no Google Scholar e em outros bancos de dados disponíveis visando reunir a literatura científica pertinente sobre a saúde mental no Haiti. A consulta de obras de referência e da literatura “cinzenta” sobre o Haiti completou as pesquisas. A primeira parte descreve os principais dados históricos, econômicos, sociológicos e antropológicos que permitem entender sumariamente o Haiti e sua população. São abordadas a demografia, a estrutura familiar, a economia haitiana e a religião. A segunda parte trata da saúde mental e dos serviços de saúde mental. São examinados: a epidemiologia elementar das doenças mentais, as crenças sobre as doenças mentais, os modelos explicativos, as demonstrações de desespero, os comportamentos de busca de auxílio, a configuração dos serviços de saúde mental e o estudo das relações entre a religião e a saúde mental

Possible Stratification Mechanism in Granular Mixtures

We propose a mechanism to explain what occurs when a mixture of grains of different sizes and different shapes (i.e. different repose angles) is poured into a quasi-two-dimensional cell. Specifically, we develop a model that displays spontaneous stratification of the large and small grains in alternating layers. We find that the key requirement for stratification is a difference in the repose angles of the two pure species, a prediction confirmed by experimental findings. We also identify a kink mechanism that appears to describe essential aspects of the dynamics of stratification.Comment: 4 pages, 4 figures, http://polymer.bu.edu/~hmakse/Home.htm

Volatility distribution in the S&P500 Stock Index

We study the volatility of the S&P500 stock index from 1984 to 1996 and find that the volatility distribution can be very well described by a log-normal function. Further, using detrended fluctuation analysis we show that the volatility is power-law correlated with Hurst exponent $\alpha\cong0.9$.Comment: 6 pages, 5 figure

Congenital bipartite lunate presenting as a misdiagnosed lunate fracture: a case report

<p>Abstract</p> <p>Introduction</p> <p>A rare case of congenital bipartite lunate in a child is reported. Carpal variants are very uncommon as independent entities, with only three previous reports of this condition in the English literature.</p> <p>Case presentation</p> <p>An 11-year-old Caucasian boy presented with pain in the left wrist after a fall. Radiographs in the emergency department demonstrated a lunate that was divided into palmar and dorsal parts, causing a misdiagnosis of fractured lunate. Magnetic resonance imaging was then used to differentiate between the two diagnoses.</p> <p>Conclusion</p> <p>Very few cases of bipartite lunate have been reported in the literature, and unless awareness is raised about congenital anomalies such as this variant, confusion may arise.</p

Correlations in Economic Time Series

The correlation function of a financial index of the New York stock exchange, the S&P 500, is analyzed at 1 min intervals over the 13-year period, Jan 84 -- Dec 96. We quantify the correlations of the absolute values of the index increment. We find that these correlations can be described by two different power laws with a crossover time t_\times\approx 600 min. Detrended fluctuation analysis gives exponents $\alpha_1=0.66$ and $\alpha_2=0.93$ for $t<t_\times$ and $t>t_\times$ respectively. Power spectrum analysis gives corresponding exponents $\beta_1=0.31$ and $\beta_2=0.90$ for $f>f_\times$ and $f< f_\times$ respectively.Comment: 6 pages, 2 figure

Dynamics of a ferromagnetic domain wall and the Barkhausen effect

We derive an equation of motion for the the dynamics of a ferromagnetic domain wall driven by an external magnetic field through a disordered medium and we study the associated depinning transition. The long-range dipolar interactions set the upper critical dimension to be $d_c=3$, so we suggest that mean-field exponents describe the Barkhausen effect for three-dimensional soft ferromagnetic materials. We analyze the scaling of the Barkhausen jumps as a function of the field driving rate and the intensity of the demagnetizing field, and find results in quantitative agreement with experiments on crystalline and amorphous soft ferromagnetic alloys.Comment: 4 RevTex pages, 3 ps figures embedde

Insights into the pathogenesis of ulcerative colitis from a murine model of stasis-induced dysbiosis, colonic metaplasia, and genetic susceptibility

Author Posting. © The Author(s), 2016. This is the author's version of the work. It is posted here by permission of American Physiological Society for personal use, not for redistribution. The definitive version was published in American Journal of Physiology-Gastrointestinal and Liver Physiology 310 (2016): G973-G988, doi:10.1152/ajpgi.00017.2016.Gut dysbiosis, host genetics, and environmental triggers are implicated as causative factors in inflammatory bowel disease (IBD), yet mechanistic insights are lacking. Longitudinal analysis of ulcerative colitis patients following total colectomy with ileal anal anastomosis (IPAA) where >50% develop pouchitis, offers a unique setting to examine cause vs. effect. To recapitulate human IPAA, we employed a mouse model of surgically created blind self-filling (SFL) and self- emptying (SEL) ileal loops using wild-type (WT), IL-10 KO (IL10), and TLR4 KO (T4), and IL10/T4 double KO mice. After 5 weeks, loop histology, host gene/protein expression, and bacterial 16s rRNA profiles were examined. SFL exhibit fecal stasis due to directional motility oriented towards the loop end, whereas SEL remain empty. In wild type mice, SFL, but not SEL, develop pouch-like microbial communities without accompanying active inflammation. However, in genetically susceptible IL-10-/- deficient mice, SFL, but not SEL, exhibit severe inflammation and mucosal transcriptomes resembling human pouchitis. The inflammation associated with IL- 10-/- required TLR4, as animals lacking both pathways displayed little disease. Furthermore, germ-free IL10-/- mice conventionalized with SFL, but not SEL, microbiota populations develop severe colitis. These data support essential roles of stasis-induced, colon-like microbiota, TLR4- mediated colonic metaplasia, and genetic susceptibility in the development of pouchitis and possibly UC. However, these factors by themselves are not sufficient. Similarities between this model and human UC/pouchitis provide opportunities for gaining insights into the mechanistic basis of IBD and for identification of targets for novel preventative and therapeutic interventions.NIDDK DK42086 (DDRCC), UH3 DK083993, Leona and Harry Helmsley Trust (SHARE), R37 DK47722, T32 DK07074, F32 DK105728, Gastrointestinal Research Foundation of Chicago, Peter and Carol Goldman Family Research grant.2017-06-0

Near-Infrared Laser Adjuvant for Influenza Vaccine

Safe and effective immunologic adjuvants are often essential for vaccines. However, the choice of adjuvant for licensed vaccines is limited, especially for those that are administered intradermally. We show that non-tissue damaging, near-infrared (NIR) laser light given in short exposures to small areas of skin, without the use of additional chemical or biological agents, significantly increases immune responses to intradermal influenza vaccination without augmenting IgE. The NIR laser-adjuvanted vaccine confers increased protection in a murine influenza lethal challenge model as compared to unadjuvanted vaccine. We show that NIR laser treatment induces the expression of specific chemokines in the skin resulting in recruitment and activation of dendritic cells and is safe to use in both mice and humans. The NIR laser adjuvant technology provides a novel, safe, low-cost, simple-to-use, potentially broadly applicable and clinically feasible approach to enhancing vaccine efficacy as an alternative to chemical and biological adjuvants