433 research outputs found
Local Martingale and Pathwise Solutions for an Abstract Fluids Model
We establish the existence and uniqueness of both local martingale and local
pathwise solutions of an abstract nonlinear stochastic evolution system. The
primary application of this abstract framework is to infer the local existence
of strong, pathwise solutions to the 3D primitive equations of the oceans and
atmosphere forced by a nonlinear multiplicative white noise. Instead of
developing our results specifically for the 3D primitive equations we choose to
develop them in a slightly abstract framework which covers many related forms
of these equations (atmosphere, oceans, coupled atmosphere-ocean, on the
sphere, on the {\beta}-plane approximation etc and the incompressible
Navier-Stokes equations). In applications, all of the details are given for the
{\beta}-plane approximation of the oceans equations
How colonization bottlenecks, tissue niches, and transmission strategies shape protozoan infections
Protozoan pathogens such as Plasmodium spp., Leishmania spp., Toxoplasma gondii, and Trypanosoma spp. are often associated with high-mortality, acute and chronic diseases of global health concern. For transmission and immune evasion, protozoans have evolved diverse strategies to interact with a range of host tissue environments. These interactions are linked to disease pathology, yet our understanding of the association between parasite colonization and host homeostatic disruption is limited. Recently developed techniques for cellular barcoding have the potential to uncover the biology regulating parasite transmission, dissemination, and the stability of infection. Understanding bottlenecks to infection and the in vivo tissue niches that facilitate chronic infection and spread has the potential to reveal new aspects of parasite biology
Parameter Estimation for the Stochastically Perturbed Navier-Stokes Equations
We consider a parameter estimation problem to determine the viscosity
of a stochastically perturbed 2D Navier-Stokes system. We derive several
different classes of estimators based on the first Fourier modes of a
single sample path observed on a finite time interval. We study the consistency
and asymptotic normality of these estimators. Our analysis treats strong,
pathwise solutions for both the periodic and bounded domain cases in the
presence of an additive white (in time) noise.Comment: to appear in SP
Epidemic space
The aim of this article is to highlight the importance of 'spatiality' in understanding the materialization of risk society and cultivation of risk sensibilities. More specifically it provides a cultural analysis of pathogen virulence (as a social phenomenon) by means of tracing and mapping the spatial flows that operate in the uncharted zones between the microphysics of infection and the macrophysics of epidemics. It will be argued that epidemic space consists of three types of forces: the vector, the index and the vortex. It will draw on Latour's Actor Network Theory to argue that epidemic space is geared towards instability when the vortex (of expanding associations and concerns) displaces the index (of finding a single cause)
Editorial
Deise Mancebo, Anna Uziel, Ariane P. Ewald, Eleonôra T. Prestrelo, Luciano da Fonseca Eli
CONCEITOS APLICADOS À POLUIÇÃO DO SOLO DECORRENTE DO DERRAME DE PETRÓLEO E SEUS DERIVADOS
A camada superficial da crosta terrestre, chamada de solo, tem fundamental importância para a vida de várias espécies. Porém, muitas atividades decorrentes do ser humano têm provocado a poluição do solo. O aumento constante da produção de lixo é o principal responsável pela poluição do solo. O chorume e a produção de gases ocorrem durante o processo de decomposição do acúmulo de lixo, o chorume é um líquido poluente e com forte odor, ele infiltra o solo, causando a contaminação do lençol freático. A utilização de agrotóxicos, pesticida e fertilizantes químicos nas atividades agrícolas também contaminam o solo, córregos e rios, sendo prejudiciais às formas de vida microbiológicas presentes no solo. A contaminação do solo com petróleo cru e seus derivados vêm se tornando um grande problema mundial, prejudicial ao solo devido aos seus compostos tóxicos, presentes em concentrações elevadas. A biorremediação é o processo pelo qual organismos vivos, como microrganismos,fungos, plantas, onde suas enzimas são utilizadas para reduzir as contaminações no ambiente
Perfil da qualidade do Biodiesel, Diesel B S10 e B S500 em uma distribuidora na Região Norte do Brasil / Quality profile of Biodiesel, Diesel B S10 and B S500 in a distributor in Northern Brazil
O Biodiesel é misturado ao diesel rodoviário, atualmente variando entre 10% e 12% de biodiesel, formando o diesel B S10 e Diesel B S500 que é distribuído para os postos revendedores e consumido em todo país. Esse percentual é responsável pela diminuição de enxofre emitido para atmosfera, pois o biodiesel não possui esse contaminante em sua composição, além de proporcionar efeitos de degradação biológica e físico-química extremamente danosos aos consumidores finais. O biodiesel utilizado na região norte é afetado pela logística, clima, tempo de armazenagem e pela própria higroscopicidade, agregando mais umidade do que outras regiões do país com a consequente elevação do teor de água acima do limite especificado de 350 mg/kg, regulado pela ANP n° 45/2014. Pretendeu-se com este trabalho traçar um perfil das análises físico-químicas dos produtos comercializado na região, bem como realizar um monitoramento sistemático do biodiesel e diesel B armazenados nos tanques de uma distribuidora da região norte. Face às misturas realizadas do biodiesel com o diesel fornecido entregue em Manaus buscou-se também traçar um do perfil da qualidade desses combustíveis nos tanques da distribuidora e que são comercializados para os postos de gasolina e consumidor final. Observando-se que biodiesel apresentou uma diminuição do teor de água mais ainda está acima do limite de especificação, o diesel B S10 está próximo do limite que atualmente é 200 mg/kg e o B S500 apresentou valor de teor de água abaixo de 300 mg/kg.
No differences in in vivo kinematics between six different types of knee prostheses
Purpose: The aim of this study was to compare a broad range of total knee prostheses with different design parameters to determine whether in vivo kinematics was consistently related to design. The hypothesis was that there are no clear recognizable differences in in vivo kinematics between different design parameters or prostheses. Methods: At two sites, data were collected by a single observer on 52 knees (49 subjects with rheumatoid arthritis or osteoarthritis). Six different total knee prostheses were used: multi-radius, single-radius, fixed-bearing, mobilebearing, posterior-stabilized, cruciate retaining and cruciate sacrificing. Knee kinematics was recorded using fluoroscopy as the patients performed a step-up motion. Results: There was a significant effect of prosthetic design on all outcome parameters; however, post hoc tests showed that the NexGen group was responsible for 80% of the significant values. The range of knee flexion was much smaller in this group, resulting in smaller anterior-posterior translations and rotations. Conclusion: Despite kinematics being generally consistent with the kinematics intended by their design, there were no clear recognizable differences in in vivo kinematics between different design parameters or prostheses. Hence, the differences in design parameters or prostheses are not distinct enough to have an effect on clinical outcome of patients.Biomechanical EngineeringMechanical, Maritime and Materials Engineerin
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