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We study the stochastic force dynamics of a model microswimmer (Chlamydomonas reinhardtii), using a combined experimental, theoretical, and numerical approach. While swimming dynamics have been extensively studied using hydrodynamic approaches, which infer forces from the viscous flow field, we directly measure the stochastic forces generated by the microswimmer using an optical trap via the photon momentum method. We analyze the force dynamics by modeling the microswimmer as a self-propelled particle, \`a la active matter, and analyze its energetics using methods from stochastic thermodynamics. We find complex oscillatory force dynamics and power dissipation on the order of ${10}^{6}\phantom{\rule{4pt}{0ex}}{k}_{B}T/s\phantom{\rule{4pt}{0ex}}(\ensuremath{\sim}\text{fW}$).

We study the stochastic force dynamics of a model microswimmer (Chlamydomonas reinhardtii), using a combined experimental, theoretical, and numerical approach. While swimming dynamics have been extensively studied using hydrodynamic approaches, which infer forces from the viscous flow field, we directly measure the stochastic forces generated by the microswimmer using an optical trap via the photon momentum method. We analyze the force dynamics by modeling the microswimmer as a self-propelled particle, à la active matter, and analyze its energetics using methods from stochastic thermodynamics. We find complex oscillatory force dynamics and power dissipation on the order of 10^{6}k_{B}T/s(∼fW).

A dinâmica envolvida no processo de extração de petróleo em ambiente offshore envolve malhas de dutos interligando poços a plataformas e estas a navios aliviadores, permitindo o escoamento produtivo realizado. Como ofensor nesse ambiente marinho, a salinidade característica da água é fonte de corrosão nos dutos que compõem a cadeia de produção submarina. O presente trabalho buscou, por meio da utilização da Metodologia de Análise e Solução de Problemas (MASP) tratar o caso específico de um oleoduto submarino que apresenta corrosividade severa que poderia causar sérios danos ambientais, além de todo impacto à imagem da organização responsável pela extração de petróleo. A partir dessa sistemática, objetivou-se identificar as causas responsáveis para ocorrência não desejada, elaborar e executar um plano de ação que evite recorrência, com posterior verificação da eficácia e padronização. Os resultados obtidos atenderam aos objetivos propostos, sendo possível determinar que o fator gerador do evento indesejado fora a dosagem inadequada de desemulsificante no tratamento do petróleo produzido e com a padronização de parâmetros operacionais da planta de processo. Houve êxito na eliminação do problema com a perenização do conhecimento obtido para manutenção da operação da plataforma dentro dos quesitos considerados seguros em relação ao meio ambiente, pessoas e patrimônio.

The dynamics involved in the process of oil extraction in the offshore environment involves pipeline meshes interconnecting wells to platforms and these to relief ships, allowing the productive flow realized. As an offender in this marine environment, salinity characteristic of water is a source of corrosion in the pipelines that make up the underwater production chain. The present work sought to treat the specific case of a submarine pipeline that presents severe corrosivity that could cause serious environmental damages, as well as the impact of the image of the organization responsible for oil extraction. Based on this systematics, the objective was to identify the responsible causes for undesired occurrence, to elaborate and execute a plan of action that avoids recurrence, with subsequent verification of efficacy and standardization. The obtained results met the proposed objectives and it was possible to determine that the factor generating the undesired event was the inadequate dosage of demulsifier in the treatment of the oil produced and with the standardization of the operational parameters of the process plant. There was success in eliminating the problem with the maintenance of the knowledge obtained to maintain the operation of the platform within the issues considered safe in relation to the environment, people and assets. A dinâmica envolvida no processo de extração de petróleo em ambiente offshore envolve malhas de dutos interligando poços a plataformas e estas a navios aliviadores, permitindo o escoamento produtivo realizado. Como ofensor nesse ambiente marinho, a salinidade característica da água é fonte de corrosão nos dutos que compõem a cadeia de produção submarina. O presente trabalho buscou, por meio da utilização da Metodologia de Análise e Solução de Problemas (MASP) tratar o caso específico de um oleoduto submarino que apresenta corrosividade severa que poderia causar sérios danos ambientais, além de todo impacto à imagem da organização responsável pela extração de petróleo. A partir dessa sistemática, objetivou-se identificar as causas responsáveis para ocorrência não desejada, elaborar e executar um plano de ação que evite recorrência, com posterior verificação da eficácia e padronização. Os resultados obtidos atenderam aos objetivos propostos, sendo possível determinar que o fator gerador do evento indesejado fora a dosagem inadequada de desemulsificante no tratamento do petróleo produzido e com a padronização de parâmetros operacionais da planta de processo. Houve êxito na eliminação do problema com a perenização do conhecimento obtido para manutenção da operação da plataforma dentro dos quesitos considerados seguros em relação ao meio ambiente, pessoas e patrimônio.

Aggregatibacter actinomycetemcomitans is a Gram-negative bacillus, member of the HACEK group of bacteria, and it is a very rare cause of endocarditis. It is also an extremely rare cause of device-associated infection of the heart. We describe the case of a 25 year-old man who presented with pacemaker-associated endocarditis due to Aggregatibacter actinomycetemcomitans and also discuss the implications and treatment of this organism.

Background and objectives: Patients undergoing total hip arthroplasty (THA) may have femoral deformities classified as either coxa vara, coxa valga, or physiologic. Understanding patients' anatomies is of importance for surgeons in an effort to tailor not only surgical approach, but also implant selection, and ultimately ensure optimal outcomes. The goal of the present study is to determine the efficacy of implanting a lower neck shaft angle (NSA) femoral stem in patients with coxa vara deformities and determine short-term clinical outcomes. Design: A retrospective chart review study. Methods: The study took place at The Texas Center for Joint Replacement in Plano, Texas. Two patient groups, clinical outcomes group and EOS group, were used for this study. The clinical outcomes group contained 55 patients who had undergone primary THA surgery from June 2013 to June 2015 by the senior author. The EOS group contained 36 patients who had undergone primary THA, and completed both preoperative and postoperative biplanar X-rays (low dose imaging device EOS) to obtain three-dimensional reconstructions of the skeletal system from October 2015 to November 2016. Operations were performed in all hips through the anterior supine intermuscular approach utilizing a 123° NSA femoral stem, which was lower than the NSA (133°) found in standard femoral stem implants. Outcome measures: Pre- and postoperative Harris hip scores used to assess clinical outcomes following surgery. Pre- and postoperative femoral offset, NSA, and femur length determined by EOS. Results: In the EOS group, mean femoral offset decreased by 3.5 mm, from 41.08 mm preoperatively to 37.6 mm postoperatively. Mean femoral NSAs decreased by 0.02°, from 123.02° preoperatively to 123.00° postoperatively. Mean femur length decreased by 2.4mm, from 404.2 mm preoperatively to 401.8 mm postoperatively. In the clinical outcomes group, mean Harris hip scores rose from 47 preoperatively to 93 postoperatively. Hip flexion range of motion improved from 87.5° preoperatively to 98° postoperatively. Conclusion: The lower NSA femoral stem examined in this study was proven to accurately restore NSA by 0.03°, femoral offset by 3.47 mm, and femur length by 2 mm, all within clinically documented satisfactory ranges without no revisions, suggesting excellent clinical outcomes in patients with coxa vara hip deformities. THA surgeons may consider utilizing femoral stems with a lower NSA in an effort to adequately restore hip function in patients with coxa vara hip deformities. Trial registration: This is a retrospective chart review study, therefore registration was not required.

LBBB and Heart Block. Background: Patients with left bundle branch block (LBBB) undergoing right heart catheterization can develop complete heart block (CHB) or right bundle branch block (RBBB) in response to right bundle branch (RBB) trauma. We hypothesized that LBBB patients with an initial r wave (≥1 mm) in lead V1 have intact left to right ventricular septal (VS) activation suggesting persistent conduction over the left bundle branch. Trauma to the RBB should result in RBBB pattern rather than CHB in such patients. Methods: Between January 2002 and February 2007, we prospectively evaluated 27 consecutive patients with LBBB developing either CHB or RBBB during right heart catheterization. The prevalence of an r wave ≥1 mm in lead V1 was determined using 118 serial LBBB electrocardiographs (ECGs) from our hospital database. Results: Catheter trauma to the RBB resulted in CHB in 18 patients and RBBB in 9 patients. All 6 patients with ≥1 mm r wave in V1 developed RBBB. Among these 6 patients q wave in lead I, V5, or V6 were present in 3. Four patients (3 in CHB group and 1 in RBBB group) developed spontaneous CHB during a median follow-up of 61 months. V1 q wave ≥1 mm was present in 28% of hospitalized complete LBBB patients. Conclusions: An initial r wave of ≥1 mm in lead V1 suggests intact left to right VS activation and identifies LBBB patients at low risk of CHB during right heart catheterization. These preliminary findings indicate that an initial r wave of ≥1 mm in lead V1, present in approximately 28% of ECGs with classically defined LBBB, may constitute a new exclusion criterion when defining complete LBBB. (J Cardiovasc Electrophysiol, Vol. pp. 781-785, July 2010)

El presente trabajo se lo ha desarrollado pensando en los servicios que las nuevas tecnologías ofrecerán y además pensando hacia donde las tecnologías actuales tienden a migrar, es por ello, que se tiene objetivos claves como dar a conocer los conceptos básicos de la tecnología MPLS, presentar soluciones de proveedores de servicio a empresas que deseen entablar redes de voz y datos con sus sucursales mediante el transporte confiable punto a punto utilizando etiquetamiento de paquetes, validar el desempeño de la tecnología MPLS mediante aplicaciones como: Redes Privadas Virtuales, Ingeniería de Tráfico y Calidad de Servicio. Al describir la funcionalidad de una red MPLS se indica las funcionalidades de los elementos participantes en un dominio, induciendo además una teoría introductoria a las diversas aplicaciones que se pueden ofrecer al tener a esta tecnología ya implementada en el Backbone de un proveedor de servicios de red. El diseño que puede ser ofrecido por un proveedor de servicios a una empresa que desee conectar sus sucursales por medio de tecnologías de transporte que le garanticen fiabilidad en el manejo y envío de su información debe ser el mas apropiado, dando a conocer la topología de red y las herramientas representativas para el diseño de la misma. La implementación del diseño de la topología de la red MPLS con el uso de herramientas muy poderosas tales como el simulador Dynamips debe presentar características que permitan tener un visión clara de lo que será una implementación con equipos reales.