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The directional instability problem in systems with frictional contacts

Pinto da Costa, A.; Martins, J. A. C.; Figueiredo, I. N.; Júdice, J. J.
Fonte: Universidade de Coimbra Publicador: Universidade de Coimbra
Tipo: Artigo de Revista Científica Formato: aplication/PDF
ENG
Relevância na Pesquisa
36.39%
The research summarized in this paper addresses the directional instability of finite dimensional systems with unilateral frictional contacts. Conditions for the occurrence of this divergence type instability are discussed, complementarity formulations are developed, and numerical procedures are proposed for the solution of the corresponding non-smooth stability eigenproblems. Various examples are analytically or numerically solved and discussed, namely some finite element examples that have instability modes involving evolution towards slip or stick in different portions of the contact surface.; http://www.sciencedirect.com/science/article/B6V29-4B2CKPM-3/1/73c607a92e3ae8a3ac0468429856b8d5

Nonlocal magnetorotational instability

MIKHAILOVSKII, A. B.; LOMINADZE, J. G.; Galvao, Ricardo Magnus Osorio; CHURIKOV, A. P.; KHARSHILADZE, O. A.; EROKHIN, N. N.; AMADOR, C. H. S.
Fonte: AMER INST PHYSICS Publicador: AMER INST PHYSICS
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
36.39%
An analytical theory of the nonlocal magnetorotational instability (MRI) is developed for the simplest astrophysical plasma model. It is assumed that the rotation frequency profile has a steplike character, so that there are two regions in which it has constant different values, separated by a narrow transition layer. The surface wave approach is employed to investigate the MRI in this configuration. It is shown that the main regularities of the nonlocal MRI are similar to those of the local instability and that driving the nonaxisymmetric MRI is less effective than the axisymmetric one, also for the case of the nonlocal instability. The existence of nonlocal instabilities in nonmagnetized plasma is predicted. (c) 2008 American Institute of Physics.

Contributions to the theory of magnetorotational instability and waves in a rotating plasma

MIKHAILOVSKII, A. B.; LOMINADZE, J. G.; CHURIKOV, A. P.; TSYPIN, V. S.; EROKHIN, N. N.; EROKHIN, N. S.; KONOVALOV, S. V.; PASHITSKII, E. A.; STEPANOV, A. V.; VLADIMIROV, S. V.; Galvao, Ricardo Magnus Osorio
Fonte: MAIK NAUKA/INTERPERIODICA/SPRINGER Publicador: MAIK NAUKA/INTERPERIODICA/SPRINGER
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
36.39%
The one-fluid magnetohydrodynamic (MHD) theory of magnetorotational instability (MRI) in an ideal plasma is presented. The theory predicts the possibility of MRI for arbitrary 0, where 0 is the ratio of the plasma pressure to the magnetic field pressure. The kinetic theory of MRI in a collisionless plasma is developed. It is demonstrated that as in the ideal MHD, MRI can occur in such a plasma for arbitrary P. The mechanism of MRI is discussed; it is shown that the instability appears because of a perturbed parallel electric field. The electrodynamic description of MRI is formulated under the assumption that the dispersion relation is expressed in terms of the permittivity tensor; general properties of this tensor are analyzed. It is shown to be separated into the nonrotational and rotational parts. With this in mind, the first step for incorporation of MRI into the general theory of plasma instabilities is taken. The rotation effects on Alfven waves are considered.

Avaliação tomográfica dinâmica pré e pós-reconstrução do ligamento patelofemoral medial de pacientes com instabilidade patelar recidivante; Dynamic computerized tomography for analyzing patients with patellar instability before and after medial patellofemoral ligament reconstruction

Gobbi, Riccardo Gomes
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 26/05/2015 PT
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A instabilidade patelar é uma patologia comum dentro da especialidade da cirurgia do joelho. O principal fator estabilizador dessa articulação é o ligamento patelofemoral medial, sendo esta a principal estrutura a ser reconstruída no tratamento cirúrgico da instabilidade patelar. Apesar de sua reconstrução apresentar excelentes resultados clínicos, não se sabe ao certo o real efeito in vivo desse procedimento no movimento da patela ao redor do fêmur. A avaliação da articulação patelofemoral tradicionalmente é feita através de exames de imagem estáticos. Com a evolução dos aparelhos de tomografia computadorizada, se tornou possível realizar esse exame durante movimento ativo, técnica ainda pouco utilizada para estudo de articulações como o joelho. O objetivo deste estudo foi padronizar o uso da tomografia de 320 fileiras de detectores para estudo dinâmico da articulação patelofemoral em pacientes com instabilidade patelar recidivante pré e pós-reconstrução do ligamento patelofemoral medial, analisando o efeito da cirurgia no trajeto da patela ao longo do arco de movimento. Foram selecionados 10 pacientes com instabilidade patelar e indicação de reconstrução do ligamento patelofemoral medial isolada...

Atlantoaxial instability secondary to agenesis of the odontoid process of the axis without rupture of the dorsal atlantoaxial ligament in a dog; Instabilidade atlantoaxial secundária à agenesia do processo odontóide do áxis sem ruptura do ligamento atlantoaxial dorsal em cão

Voll, Juliana; Voll, Rodolfo; Gaiga, Leandro Haczkiewwicz; Pigatto, João Antonio Tadeu; Teixeira, Fabio dos Santos
Fonte: Universidade Federal do Rio Grande do Sul Publicador: Universidade Federal do Rio Grande do Sul
Tipo: Artigo de Revista Científica Formato: application/pdf
ENG
Relevância na Pesquisa
36.44%
A instabilidade atlantoaxial é uma condição congênita ou traumática que causa dor cervical e vários graus de disfunção neurológica. Um caso de instabilidade atlantoaxial secundário a agenesia do processo odontóide do áxis sem evidência de ruptura do ligamento atlantoaxial dorsal em um cão tratado cirurgicamente com sucesso é relatado. Um cão da raça Lhasa Apso, macho, 9 meses de idade, 8,5 Kg atendido no Hospital de Clínicas Veterinárias da Universidade Federal do Rio Grande do Sul. O exame neurológico evidenciou hiperestesia à palpação da região cervical cranial, tetraparesia não ambulatória com reflexos aumentados e deficiência proprioceptiva nos membros torácicos e pélvicos. O exame radiográfico simples na posição ventrodorsal demonstrou agenesia do processo odontóide; não houve evidência de instabilidade atlantoaxial na posição látero lateral. O diagnóstico de instabilidade atlantoaxial secundária à agenesia de processo odontóide foi estabelecido pelos sinais clínicos e exame radiográfico na posição ventrodorsal. O cão foi submetido a tratamento cirúrgico utilizando-se a técnica de estabilização ventral com pinos transarticulares. A estabilização das vértebras foi feita com pinos de Steinmann e metilmetacrilato. Uma semana de pós-operatório o exame neurológico evidenciou tetraparesia ambulatória e o radiológico...

Polymorphic variation of mononucleotide microsatellites in healthy humans and its implications for microsatellite instability screening; Variação polimórfica de microssatélites mononucleotídicos em indivíduos normais e sua implicação no rastreamento de instabilidade de microssatélites

Cossio, Silvia Liliana; Coura, Renata dos Santos; Bortolini, Maria Cátira; Giugliani, Roberto; Prolla, Patrícia Ashton; Prolla, João Carlos
Fonte: Universidade Federal do Rio Grande do Sul Publicador: Universidade Federal do Rio Grande do Sul
Tipo: Artigo de Revista Científica Formato: application/pdf
ENG
Relevância na Pesquisa
36.39%
Racional - No Brasil, o câncer colorretal é o sexto tumor em freqüência e o quinto em mortalidade. Marcadores moleculares têm sido associados com o prognóstico da doença, especialmente em relação à resposta terapêutica e taxa de sobrevida. Dentre eles, a instabilidade de microssatélites tem sido amplamente estudada. O estado de instabilidade de microssatélites é usualmente determinado pela comparação entre tecido tumoral e tecido normal correspondente de um mesmo paciente e a instabilidade se caracteriza pela diferença no perfi l do produto de amplifi cação por PCR destes tecidos em um determinado locus. Usualmente, é utilizado um painel de cinco marcadores para este propósito. Dois deles (BAT-25 e BAT-26) são considerados monomórfi cos em populações de origem européia. Objetivo - Analisar a freqüência de variação constitutiva nos loci BAT-25 e BAT-26 em amostra de indivíduos do sul do Brasil. Métodos - Duzentos e dezesseis indivíduos saudáveis e não relacionados foram analisados para determinar a freqüência de variação alélica nestes loci. O rastreamento de variantes alélicas foi feito por “polymerase chain reaction – single strand conformation polymorphism” (PCR-SSCP). Resultados - Observou-se possível variação alélica constitutiva em 7% e 6% dos pacientes nos loci BAT-25 e BAT-26...

Political instability and inflation volatility

Aisen, Ari; Veiga, Francisco José
Fonte: Springer Netherlands Publicador: Springer Netherlands
Tipo: Artigo de Revista Científica
Publicado em /06/2008 ENG
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The views expressed in this paper are those of the authors and do not necessarily represent those of the IMF or IMF policy.; The purpose of this paper is to empirically analyze the effects of political instability, social polarization and the quality of institutions on inflation volatility over time and across countries. Using the system-GMM estimator for linear dynamic panel data models on a sample covering 160 countries, analyzed in the period from 1960 to 1999, this paper finds that higher degrees of political instability and social polarization, less democracy, and lower de facto central bank independence are associated with more volatile inflation rates. Furthermore, political instability has greater effects on inflation volatility in developing countries with lower degrees of central bank independence and economic freedom.

How does political instability affect economic growth?

Aisen, Ari; Veiga, Francisco José
Fonte: Universidade do Minho. Núcleo de Investigação em Políticas Económicas (NIPE) Publicador: Universidade do Minho. Núcleo de Investigação em Políticas Económicas (NIPE)
Tipo: Trabalho em Andamento
Publicado em //2010 ENG
Relevância na Pesquisa
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The purpose of this paper is to empirically determine the effects of political instability on economic growth. Using the system-GMM estimator for linear dynamic panel data models on a sample covering up to 169 countries, and 5-year periods from 1960 to 2004, we find that higher degrees of political instability are associated with lower growth rates of GDP per capita. Regarding the channels of transmission, we find that political instability adversely affects growth by lowering the rates of productivity growth and, to a smaller degree, physical and human capital accumulation. Finally, economic freedom and ethnic homogeneity are beneficial to growth, while democracy may have a small negative effect.; Fundação para a Ciência e a Tecnologia (FCT) - Programa Operacional Ciência e Inovação 2010 (POCI 2010); Fundo Europeu de Desenvolvimento Regional (FEDER)

How does political instability affect economic growth?

Aisen, Ari; Veiga, Francisco José
Fonte: International Monetary Fund Publicador: International Monetary Fund
Tipo: Trabalho em Andamento
Publicado em /01/2011 ENG
Relevância na Pesquisa
36.39%
The purpose of this paper is to empirically determine the effects of political instability on economic growth. Using the system-GMM estimator for linear dynamic panel data models on a sample covering up to 169 countries, and 5-year periods from 1960 to 2004, we find that higher degrees of political instability are associated with lower growth rates of GDP per capita. Regarding the channels of transmission, we find that political instability adversely affects growth by lowering the rates of productivity growth and, to a smaller degree, physical and human capital accumulation. Finally, economic freedom and ethnic homogeneity are beneficial to growth, while democracy may have a small negative effect.

Classifying and systemising uncertainty and instability : a dynamic social network approach to risk

Atkinson, Simon Reay; Mitchell, Matthew; Wehbe, Aminah; Ainsworth, Harold; Harré, Michael; Sousa, Sérgio; Wahlet, Ian
Fonte: EAID Engineer Australia Publicador: EAID Engineer Australia
Tipo: Conferência ou Objeto de Conferência
Publicado em //2014 ENG
Relevância na Pesquisa
36.39%
The narrow and probabilistic, ergodic approach to risk, to date, has potentially not fully understood or incorporated the dynamical synthetic ecology in which our systems actually operate. A dynamic synthetic ecology made even more complex and potentially uncertain and unstable through the degrees of socio-info/techno connectivity we now enjoy compared to 30 years ago. This means our decisions and solutions are often deeply entangled in ways that it is almost impossible to measure. Yet Risk Management continues to call for measured certainty based upon a potentially increasingly narrow and frozen understanding of Risk – usually ‘taken’ at the unit / operational but not the systems level. In this paper, we look at uncertainty and instability as being connected but not necessarily synonymous indicators of risk. In terms of instability, we look to classify different types of instability that a system may face including, for example, technical risks introduced through disruptive technologies.

Elimination of the numerical Cerenkov instability for spectral EM-PIC codes

Yu, P.; Xu, X.; Decyk, V. K.; Fiuza, F.; Vieira, J.; Tsung, F. S.; Fonseca, R. A.; Lu, W.; Silva, L. O.; Mori, W. B.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Publicado em //2015 ENG
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When using an electromagnetic particle-in-cell (EM-PIC) code to simulate a relativistically drifting plasma, a violent numerical instability known as the numerical Cerenkov instability (NCI) occurs. The NCI is due to the unphysical coupling of electromagnetic waves on a grid to wave–particle resonances, including aliased resonances, i.e., ω+2πμ/Δt=(k1+2πν1/Δx1)v0, where μ and ν1 refer to the time and space aliases and the plasma is drifting relativistically at velocity v0 in the View the MathML source-direction. We extend our previous work Xu et al. (2013) by recasting the numerical dispersion relation of a relativistically drifting plasma into a form which shows explicitly how the instability results from the coupling modes which are purely transverse electromagnetic (EM) modes and purely longitudinal modes in the rest frame of the plasma for each time and space aliasing. The dispersion relation for each μ and ν1 is the product of the dispersion relation of these two modes set equal to a coupling term that vanishes in the continuous limit. The new form of the numerical dispersion relation provides an accurate method of systematically calculating the growth rate and location of the mode in the fundamental Brillouin zone for any Maxwell solver for each μ and ν1. We then focus on the spectral Maxwell solver and systematically discuss its NCI modes. We show that the second fastest growing NCI mode for the spectral solver corresponds to μ=ν1=0...

A Breast Cancer Meta-Analysis of Two Expression Measures of Chromosomal Instability Reveals a Relationship with Younger Age at Diagnosis and High Risk Histopathological Variables

Endesfelder, David; McGranahan, Nicholas; Kschischo, Maik; Graham, Trevor A.; Swanton, Charles; Birkbak, Nicolai Juul; Szallasi, Zoltan
Fonte: Impact Journals LLC Publicador: Impact Journals LLC
Tipo: Artigo de Revista Científica
EN_US
Relevância na Pesquisa
36.44%
Breast cancer in younger patients often presents with adverse histopathological features, including increased frequency of estrogen receptor negative and lymph node positive disease status. Chromosomal instability (CIN) is increasingly recognised as an important prognostic variable in solid tumours. In a breast cancer meta-analysis of 2423 patients we examine the relationship between clinicopathological parameters and two distinct chromosomal instability gene expression signatures in order to address whether younger age at diagnosis is associated with increased tumour genome instability. We find that CIN, assessed by the two independently derived CIN expression signatures, is significantly associated with increased tumour size, ER negative or HER2 positive disease, higher tumour grade and younger age at diagnosis in ER negative breast cancer. These data support the hypothesis that chromosomal instability may be a defining feature of breast cancer biology and clinical outcome.

Clinical Instability of the Knee and Functional Differences Following Tibial Plateau Fractures Versus Distal Femoral Fractures

Ebrahimzadeh, Mohammad Hosein; Birjandinejad, Ali; Moradi, Ali; Fathi Choghadeh, Maysam; Rezazadeh, Jafar; Omidi-Kashani, Farzad
Fonte: Kowsar Publicador: Kowsar
Tipo: Artigo de Revista Científica
EN_US
Relevância na Pesquisa
36.44%
Background: Fractures of the knee account for about 6% of all trauma admissions. While its management is mostly focused on fracture treatment, it is not the only factor that defines the final outcome. Objectives: This study aimed to study objective and subjective outcomes after proximal tibial versus distal femoral fractures in terms of knee instability and health-related quality of life. Patients and Methods: This retrospective, cross-sectional, cohort study was carried out on 80 patients with either isolated proximal tibial (n = 42) or distal femoral (n = 38) fractures, who underwent open reduction and internal fixation. All the fractures were classified based on the Schatzker and AO classification for tibial plateau and distal femoral fractures, respectively. The patients were followed and examined by an orthopedic knee surgeon for clinical assessment of knee instability. In their last follow-up visit, these patients completed a Lysholm knee score and the short-form (SF) 36 health survey. Results: Among the 42 tibial plateau fractures, 25% were classified as Schatzker type 2. Of the 38 distal femoral fractures, we did not find any type B1 or B3 fractures. The overall prevalence of anterior and posterior instability was 42% and 20%...

Rac2-MRC-cIII-generated ROS cause genomic instability in chronic myeloid leukemia stem cells and primitive progenitors

Nieborowska-Skorska, M.; Kopinski, P.; Ray, R.; Hoser, G.; Ngaba, D.; Flis, S.; Cramer, K.; Reddy, M.; Koptyra, M.; Penserga, T.; Glodkowska-Mrowka, E.; Bolton, E.; Holyoake, T.; Eaves, C.; Cerny-Reiterer, S.; Valent, P.; Hochhaus, A.; Hughes, T.; Van der
Fonte: Amer Soc Hematology Publicador: Amer Soc Hematology
Tipo: Artigo de Revista Científica
Publicado em //2012 EN
Relevância na Pesquisa
36.44%
Chronic myeloid leukemia in chronic phase (CML-CP) is induced by BCR-ABL1 oncogenic tyrosine kinase. Tyrosine kinase inhibitors eliminate the bulk of CML-CP cells, but fail to eradicate leukemia stem cells (LSCs) and leukemia progenitor cells (LPCs) displaying innate and acquired resistance, respectively. These cells may accumulate genomic instability, leading to disease relapse and/or malignant progression to a fatal blast phase. In the present study, we show that Rac2 GTPase alters mitochondrial membrane potential and electron flow through the mitochondrial respiratory chain complex III (MRC-cIII), thereby generating high levels of reactive oxygen species (ROS) in CML-CP LSCs and primitive LPCs. MRCcIII– generated ROS promote oxidative DNA damage to trigger genomic instability, resulting in an accumulation of chromosomal aberrations and tyrosine kinase inhibitor–resistant BCR-ABL1 mutants. JAK2(V617F) and FLT3(ITD)–positive polycythemia vera cells and acute myeloid leukemia cells also produce ROS via MRCcIII. In the present study, inhibition of Rac2 by genetic deletion or a smallmolecule inhibitor and down-regulation of mitochondrial ROS by disruption of MRC-cIII, expression of mitochondriatargeted catalase, or addition of ROSscavenging mitochondria-targeted peptide aptamer reduced genomic instability. We postulate that the Rac2-MRC-cIII pathway triggers ROS-mediated genomic instability in LSCs and primitive LPCs...

Instability-induced formation and nonequilibrium dynamics of phase defects in polariton condensates

Liew, T. C. H.; Egorov, O. A.; Matuszewski, M.; Kyriienko, O.; Ma, X.; Ostrovskaya, E. A.
Fonte: American Physical Society Publicador: American Physical Society
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
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We study, theoretically and numerically, the onset and development of modulational instability in an incoherently pumped spatially homogeneous polariton condensate. Within the framework of mean-field theory, we identify regimes of modulational instability in two cases: (1) strong feedback between the condensate and reservoir, which may occur in scalar condensates, and (2) parametric scattering in the presence of polarization splitting in spinor condensates. In both cases we investigate the instability-induced textures in space and time including nonequilibrium dynamics of phase dislocations and vortices. In particular we discuss the mechanism of vortex destabilization and formation of spiraling waves. We also identify the presence of topological defects, which take the form of half-vortex pairs in the spinor case, giving an “eyelet” structure in intensity and dipole-type structure in the spin polarization. In the modulationally stable parameter domains, we observe formation of the phase defects in the process of condensate formation from an initially spatially incoherent low-density state. In analogy to the Kibble-Zurek-type scaling for nonequilibrium phase transitions, we find that the defect density scales with the pumping rate.

When Instability Increases the Effectiveness of Aid Projects

Guillaumont, Patrick; Laajaj, Rachid
Fonte: World Bank, Washington, DC Publicador: World Bank, Washington, DC
Tipo: Publications & Research :: Policy Research Working Paper; Publications & Research
ENGLISH; EN_US
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36.44%
The authors assess the effect of economic instability on the success of projects funded by the World Bank using the outcome of the projects, which is a notation of their overall success determined by the Bank's Independent Evaluation Group. It has been argued in macroeconomic studies that aid effectiveness is higher in vulnerable countries because it dampens the negative effects of shocks. The authors show that this finding is not inconsistent with the observation that the success of the projects is lower in an unstable environment. Instability, in particular the instability of exports, harms aid projects as it harms the rest of the economy, while the success of projects decreases when the total amount of aid received increases, due to absorptive capacity limitations. But this decrease is slower when instability is higher, showing a positive effect of aid through its stabilizing impact. The authors find the same results keeping only the projects funded by nonconcessionary loans, which suggests that the cushioning effect of aid extends not only to aid funded projects but to whole sets of projects. Corroborating macroeconomic findings, their results lead to the same conclusion that more aid should be allocated to more vulnerable countries...

Alliance Politics in Hybrid Regimes : Political Stability and Instability since World War II

Gagné, Jean-François
Fonte: Université de Montréal Publicador: Université de Montréal
Tipo: Thèse ou Mémoire numérique / Electronic Thesis or Dissertation
EN
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36.44%
Cette thèse étudie la stabilité et l’instabilité politique des régimes hybrides. Elle pose la question suivante : dans quelles conditions l’autorité des élites au pouvoir est-elle reconnue ou contestée? Notre réponse s’articule en lien avec le caractère inclusif ou exclusif de la coalition dirigeante : c’est-à-dire, l’alliance stratégique des élites dirigeantes avec les groupes sociaux dominants. L’inclusion de ces derniers favorise le consentement et la stabilité; leur exclusion entraîne l’affrontement et l’instabilité politique. Sa composition dépend (i) du degré de violence organisée extra-légale et (ii) du degré de pénétration de l’État sur le territoire et dans l’économie. La première variable permet d’identifier quel groupe social au sein de l’État (militaires) ou du régime (partis d’opposition) est dominant et influence les formes de communication politique avec les élites dirigeantes. La deuxième variable permet d’identifier quel groupe social au sein de l’État (fonctionnaires) ou de la société (chefs locaux) est dominant et oriente les rapports entre les régions et le pouvoir central. L’apport de la recherche est d’approfondir notre compréhension des institutions politiques dans les régimes hybrides en mettant l’accent sur l’identité des groupes sociaux dominants dans un contexte donné. La thèse propose un modèle simple...

Ring chromosome instability evaluation in six patients with autosomal rings

SODRE, C. P.; GUILHERME, R. S.; MELONI, V. F. A.; BRUNONI, D.; JULIANO, Y.; ANDRADE, J. A. D.; BELANGERO, S. I. N.; CHRISTOFOLINI, D. M.; KULIKOWSKI, L. D.; MELARAGNO, M. I.
Fonte: FUNPEC-EDITORA Publicador: FUNPEC-EDITORA
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
36.44%
Ring chromosomes are often associated with abnormal phenotypes due to loss of genomic material and also because of ring instability at mitosis after sister chromatid exchange events. We investigated ring chromosome instability in six patients with ring chromosomes 4, 14, 15, and 18 by examining 48- and 72-h lymphocyte cultures at the first, second and subsequent cell divisions after bromodeoxyuridine incorporation. Although most cells from all patients showed only one monocentric ring chromosome, ring chromosome loss and secondary aberrations were observed both in 48-and 72-h lymphocyte cultures and in metaphase cells of the different cell generations. We found no clear-cut correlation between ring size and ring instability; we also did not find differences between apparently complete rings and rings with genetic material loss. The cytogenetic findings revealed secondary aberrations in all ring chromosome patients. We concluded that cells with ring chromosome instability can multiply and survive in vivo, and that they can influence the patient's phenotype.

Novas lideranças sul-americanas: clivagens sobre o binômio estabilidade-instabilidade política; New south american leadership: cleavages in the stability-instability binomy; Nouveaux leaders sud-américains: clivage sur le binôme stabilité-instabilité politique

VILLA, Rafael Duarte
Fonte: Universidade Federal do Paraná Publicador: Universidade Federal do Paraná
Tipo: Artigo de Revista Científica
POR
Relevância na Pesquisa
36.44%
Este artigo trata da instabilidade política na América Latina, especialmente dos países componentes da Região Andina, do Cone Sul e do Brasil. Investigamos as causas do surgimento de novas lideranças políticas nesses países e a relação dessas lideranças com situações de estabilidade ou de instabilidade políticas. O artigo sustenta que o surgimento de novas lideranças na América Latina, que tem emergido numa dinâmica de estabilidade e instabilidade política, não pode ser compreendido unicamente por hipóteses que ressaltem os traços populistas ou de falhas da modernização política, dado que a casuística mais profunda de tal emergência deveria ser procurada em novas clivagens que apontam para uma renovação de elites, mas também para o surgimento de clivagens de identidade étnica e social assim como de um novo padrão de relacionamento entre movimentos sociais e novas lideranças. Concluímos que a ascensão de novas lideranças políticas nos países analisados está geralmente ligada a uma crise de legitimidade do sistema político. Assumimos também que o "neopopulismo" pode ser uma variável explicativa da emergência de novos atores nos contextos de instabilidade política, não podendo tal variável, entretanto...

Patellofemoral instability: evaluation by magnetic resonance imaging

Souza,Patricia Martins e; Gabetto,Marcelo Sadock de Sa; Serrao,Marcelo Ganem; Vieira,Luiz Antonio Martins; Oliveira,Diogo Cals de
Fonte: Sociedade Brasileira de Ortopedia e Traumatologia Publicador: Sociedade Brasileira de Ortopedia e Traumatologia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/04/2013 EN
Relevância na Pesquisa
36.44%
OBJECTIVE: To determine the contribution of magnetic resonance imaging (MRI) in evaluating patelofemoral instability. METHODS: 39 patients (45 knees) with patellar instability underwent knee magnetic resonance images between October 2009 and July 2011, at the Rede Lab's D'Or, in the city of Rio de Janeiro, State of Rio de Janeiro, were included. MRI were analyzed for the presence of bone, hyaline cartilage and soft-tissue abnormalities, as well as anatomic variants that may contribute to chronic patellar instability. RESULTS: The authors found, of the 45 knees analysed, bone changes in 44%, cartilaginous injuries in 64%, disruption of the medial patellofemoral ligament (MPFL) in 29% and joint morphology abnormalities in 73% patients. Meniscal tears were also identified in 2 (4%) patients and fibular fracture in one (2%) patient. CONCLUSION: MRI allowed the detection of predisposing factors that may contribute to the development of patellofemoral instability and the diagnosis of bone, hyaline cartilage, ligamentous and meniscal abnormalities.