160 research outputs found
Poisson geometrical symmetries associated to non-commutative formal diffeomorphisms
Let G be the group of all formal power series starting with x with
coefficients in a field k of zero characteristic (with the composition
product), and let F[G] be its function algebra. C. Brouder and A. Frabetti
introduced a non-commutative, non-cocommutative graded Hopf algebra H, via a
direct process of ``disabelianisation'' of F[G], i.e. taking the like
presentation of the latter as an algebra but dropping the commutativity
constraint. In this paper we apply a general method to provide four
one-parameters deformations of H, which are quantum groups whose semiclassical
limits are Poisson geometrical symmetries such as Poisson groups or Lie
bialgebras, namely two quantum function algebras and two quantum universal
enveloping algebras. In particular the two Poisson groups are extensions of G,
isomorphic as proalgebraic Poisson varieties but not as proalgebraic groups.
This analysis easily extends to a hudge family of Hopf algebras of similar
nature, thus yielding a method to associate to such "generalized symmetries"
some classical geometrical symmetries (such as Poisson groups and Lie
bialgebras) in a natural way: the present case then stands as a simplest, toy
model for the general situation.Comment: AMS-TeX file, 34 pages. To appear in Communications in Mathematical
Physics. Minor corrections have been fixed here and ther
The Development and Validation of a Low Back Pain Knowledge Questionnaire – LKQ
OBJECTIVE: The objective of this study was to develop and validate a questionnaire on specific knowledge about low back pain entitled "The Low Back Pain Knowledge Questionnaire". INTRODUCTION: There is a need for instruments to assess patient knowledge regarding chronic illness. Such methods can contribute to the education of patients. METHODS: The Low Back Pain Knowledge Questionnaire was developed through five focus groups. The questionnaire was distributed to 50 patients to assess their comprehension of the terms. To assess the reproducibility, 20 patients were surveyed by two different interviewers on the same day and twice by a single interviewer with a one-to-two week interval. For the construct validation, the Low Back Pain Knowledge Questionnaire was given to 20 healthcare professionals with knowledge on low back pain and 20 patients to determine whether the questionnaire would discriminate between the two different populations. To assess the sensitivity of the questionnaire to changes in the knowledge level of the patients, it was given to 60 patients who were randomly assigned to the Intervention Group and the Control Group. The Intervention Group answered the questionnaire both before and after attending a chronic back pain educational program (back school), whereas the Control Group answered the questionnaire twice with an interval of one month and no educational intervention. RESULTS: The focus groups generated a questionnaire with 16 items. The Spearman's correlation coefficient and the intra-class correlation coefficients ranged from 0.61 to 0.95 in the assessments of the intra-observer and inter-observer reproducibility (p< 0.01). In the construct validation, the healthcare professionals and patients showed statistically different scores (p< 0.001). In the phase regarding the sensitivity to change, the Intervention Group exhibited a significant increase in their specific knowledge over the Control Group (p< 0.001). CONCLUSION: The Low Back Pain Knowledge Questionnaire was validated and proved to be reproducible, valid and sensitive to changes in patient knowledge
Cell Model System for Glucocorticoid-Induced Osteoporosis
Dexamethasone, a corticosteroid that inhibits inflammation, is commonly used for the treatment of arthritis. However, glucocorticoid-induced osteoporosis is a side effect that commonly occurs after dexamethasone treatment. One of the mechanisms by which glucocorticoids are thought to suppress bone formation is through their effect on the wnt/ ß-catenin signaling pathway. The wnt/ ß-catenin pathway is essential in the formation of new osteoblasts and the prevention of osteoblast apoptosis. However, treatment with dexamethasone is thought to destabilize and inhibit nuclear translocation of ß-catenin, decreasing the survival of osteoblasts. By using precursor mouse osteoblast MC3T3 cells, we will analyze antisense morpholino oligonucleotide targeted to Col11a1 as a potential treatment to reverse or block the detrimental effects of dexamethasone on the wnt signaling pathway. MC3T3 cells will be exposed to different treatments in vitro, then aspects of the cell cycle will be analyzed by markers of apoptosis, specific signaling pathways, and cell proliferation rates. While the data obtained in this experiment is relevant to human cell functioning, future research with human cells will strengthen this line of investigation further and establish greater relevance to human health
Viscosity and Diffusion: Crowding and Salt Effects in Protein Solutions
We report on a joint experimental-theoretical study of collective diffusion
in, and static shear viscosity of solutions of bovine serum albumin (BSA)
proteins, focusing on the dependence on protein and salt concentration. Data
obtained from dynamic light scattering and rheometric measurements are compared
to theoretical calculations based on an analytically treatable spheroid model
of BSA with isotropic screened Coulomb plus hard-sphere interactions. The only
input to the dynamics calculations is the static structure factor obtained from
a consistent theoretical fit to a concentration series of small-angle X-ray
scattering (SAXS) data. This fit is based on an integral equation scheme that
combines high accuracy with low computational cost. All experimentally probed
dynamic and static properties are reproduced theoretically with an at least
semi-quantitative accuracy. For lower protein concentration and low salinity,
both theory and experiment show a maximum in the reduced viscosity, caused by
the electrostatic repulsion of proteins. The validity range of a generalized
Stokes-Einstein (GSE) relation connecting viscosity, collective diffusion
coefficient, and osmotic compressibility, proposed by Kholodenko and Douglas
[PRE 51, 1081 (1995)] is examined. Significant violation of the GSE relation is
found, both in experimental data and in theoretical models, in semi-dilute
systems at physiological salinity, and under low-salt conditions for arbitrary
protein concentrations
Brazilian consensus on the treatment of fibromyalgia
UNIFESP Ambulatório de FibromialgiaUFPR HC ambulatório de fibromialgiaUNIFESPUNIFESP Setor de reumatismos de partes molesPUC-SP Departamento de MedicinaPUC-Campinas Hospital Universitário Serviço de ReumatologiaSociedade Brasileira de ReumatologiaSanta Casa de Belo Horizonte Ambulatório de Fibromialgia Programa de Residência Médica em ReumatologiaFMUSP HC Serviço de ReumatologiaSanta Casa de Campo Grande Setor de Reumatologia programa de Residência em Clínica MédicaUniversidade Federal de Ciências da Saúde de Porto AlegreUNiSULUniversidade Federal do Espírito Santo Hospital Universitário serviço de ReumatologiaSociedade Brasileira de Clínica MédicaSociedade Brasileira para o Estudo da DorAssociação Brasileira de Medicina Física e ReabilitaçãoUniversidade de São Paulo Faculdade de MedicinaUniversidade Federal FluminenseAcademia Brasileira de Neurologia Departamento de DorEuropean Neurological Society Subcomitê de DorPeripheral Nerve SocietyFMUSP Grupo de MãoSociedade Brasileira de ortopedia e TraumatologiaAxia.Bio farmacoeconomia e pesquisa em saúdeUNIFESP Núcleo de Gestão de PesquisasUNIFESP, Ambulatório de FibromialgiaUNIFESP, Setor de reumatismos de partes molesUNIFESP, Núcleo de Gestão de PesquisasSciEL
Ecosystem Overfishing in the Ocean
Fisheries catches represent a net export of mass and energy that can no longer be used by trophic levels higher than those fished. Thus, exploitation implies a depletion of secondary production of higher trophic levels (here the production of mass and energy by herbivores and carnivores in the ecosystem) due to the removal of prey. The depletion of secondary production due to the export of biomass and energy through catches was recently formulated as a proxy for evaluating the ecosystem impacts of fishing–i.e., the level of ecosystem overfishing. Here we evaluate the historical and current risk of ecosystem overfishing at a global scale by quantifying the depletion of secondary production using the best available fisheries and ecological data (i.e., catch and primary production). Our results highlight an increasing trend in the number of unsustainable fisheries (i.e., an increase in the risk of ecosystem overfishing) from the 1950s to the 2000s, and illustrate the worldwide geographic expansion of overfishing. These results enable to assess when and where fishing became unsustainable at the ecosystem level. At present, total catch per capita from Large Marine Ecosystems is at least twice the value estimated to ensure fishing at moderate sustainable levels
Disentangling the pollen signal from fen systems : modern and Holocene studies from southern and eastern England
Thick deposits of peat derived from fen environments accumulated in the coastal lowland areas adjacent to the North Sea during the middle and late Holocene. These sediments are frequently used in pollen-based reconstructions of in situ and more distant vegetation. However, discriminating between wetland and dry land originating pollen signals, and between the potential fen communities present in the wetland, is complex. In this study, a suite of analytical approaches are used to explore the pollen signal of modern fen communities and compare them against Holocene pollen assemblages. At two sites in eastern England, Woodwalton Fen and Upton Broad, vegetation composition was recorded around a series of moss polster sampling points. The communities investigated included herbaceous fen communities under different cutting regimes, a grazed area, glades, and woodland with canopies dominated by Alnus glutinosa and Betula. Cluster analysis is used to provide an overview of, and compare the structure within, the datasets consisting of the vegetation, the vegetation converted to palynological equivalents, and the pollen data. It is demonstrated that any loss of taxonomic precision in pollen identifications does not pose particular problems when attempting to identify fen communities, including tall-herbaceous vegetation, in the pollen record. Indices of Association imply pollen presence can be interpreted as indicating the local presence for some taxa, though few of these are confined to a particular community. Herbaceous fen vegetation subject to different management regimes are, however, shown to produce distinctive pollen signatures. Middle and late Holocene pollen assemblages from eastern (Fenland) and southern (Romney Marsh) England, interpreted as derived from fen vegetation, are compared against the modern pollen dataset using ordination. Most of the fossil samples plot out within or adjacent to the groupings produced by the modern samples in the ordinations. While these investigations demonstrate that modern pollen work can help improve the interpretation of Holocene assemblages they also call attention to a number of limitations including the restricted range of communities from which modern samples are currently available and the potential for non-analogous modern vegetation. The paper concludes with ideas to aid the interpretation of pollen data collected from fen peats and suggestions for future work
CD8+ T Cells and IFN-γ Mediate the Time-Dependent Accumulation of Infected Red Blood Cells in Deep Organs during Experimental Cerebral Malaria
Background: Infection with Plasmodium berghei ANKA (PbA) in susceptible mice induces a syndrome called experimental cerebral malaria (ECM) with severe pathologies occurring in various mouse organs. Immune mediators such as T cells or cytokines have been implicated in the pathogenesis of ECM. Red blood cells infected with PbA parasites have been shown to accumulate in the brain and other tissues during infection. This accumulation is thought to be involved in PbA–induced pathologies, which mechanisms are poorly understood. Methods and Findings: Using transgenic PbA parasites expressing the luciferase protein, we have assessed by real-time in vivo imaging the dynamic and temporal contribution of different immune factors in infected red blood cell (IRBC) accumulation and distribution in different organs during PbA infection. Using deficient mice or depleting antibodies, we observed that CD8 + T cells and IFN-c drive the rapid increase in total parasite biomass and accumulation of IRBC in the brain and in different organs 6–12 days post-infection, at a time when mice develop ECM. Other cells types like CD4 + T cells, monocytes or neutrophils or cytokines such as IL-12 and TNF-a did not influence the early increase of total parasite biomass and IRBC accumulation in different organs. Conclusions: CD8 + T cells and IFN-c are the major immune mediators controlling the time-dependent accumulation of P. berghei-infected red blood cells in tissues
Assessment of acute myocardial infarction: current status and recommendations from the North American society for cardiovascular imaging and the European society of cardiac radiology
There are a number of imaging tests that are used in the setting of acute myocardial infarction and acute coronary syndrome. Each has their strengths and limitations. Experts from the European Society of Cardiac Radiology and the North American Society for Cardiovascular Imaging together with other prominent imagers reviewed the literature. It is clear that there is a definite role for imaging in these patients. While comparative accuracy, convenience and cost have largely guided test decisions in the past, the introduction of newer tests is being held to a higher standard which compares patient outcomes. Multicenter randomized comparative effectiveness trials with outcome measures are required
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