1,367 research outputs found
Prevalencia, caracterización clínica y epidemiológica de la tuberculosis en personal de salud en El Salvador
La tuberculosis (TB) es la segunda causa de muerte por un único agente infeccioso a nivel mundial. Es mundialmente aceptado que el
personal de salud tiene riesgo aumentado de adquirir TB en comparación con la población general. Según datos de 2010, se estima
que 30,271 personas componen al personal del sistema público de salud en todo El Salvador, 12,926 (42.7%) en la Región Metropolitana.
Hasta este momento no existían datos que expresaran la importancia y el efecto de este problema en El Salvador. En esta investigación
descriptiva se analizaron los casos de TB en personal de salud de la Región Metropolitana de El Salvador y se demostró que éste tiene 2 a 5 veces el riesgo de enfermar de TB (IC=0.95) que la población general.Tesis para optar al Título de Doctor en Medicin
A fluorometric method for the assay of protein kinase activity
Protein kinases constitute one of the largest protein families in nature. Current methods to assay their activity involve the use of radioactive ATP or very expensive reagents. In this work, we developed a highly sensitive, cost-effective and straightforward protocol to measure protein kinase activity using a microplate layout. Released ADP is converted into NAD+, which is quantified by its fluorescent properties after alkaline treatment (linear range 0–10 nmol ADP). To validate our protocol, we characterized a recombinant calcium-dependent protein kinase from potato. Overall, this tool represents a critical step forward in the functional characterization of protein kinases.Fil: Rojas, Bruno Ezequiel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Agrobiotecnología del Litoral. Universidad Nacional del Litoral. Instituto de Agrobiotecnología del Litoral; ArgentinaFil: Santin, Franco. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; ArgentinaFil: Ulloa, Rita Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; ArgentinaFil: Iglesias, Alberto Alvaro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Agrobiotecnología del Litoral. Universidad Nacional del Litoral. Instituto de Agrobiotecnología del Litoral; ArgentinaFil: Figueroa, Carlos Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Agrobiotecnología del Litoral. Universidad Nacional del Litoral. Instituto de Agrobiotecnología del Litoral; Argentin
Attention-based Multi-fidelity Machine Learning Model for Computational Fractional Flow Reserve Assessment
Coronary Artery Disease (CAD) is one of the most common forms of heart
disease, which is caused by a buildup of atherosclerotic plaque (known as
stenosis) in the coronary arteries, leading to insufficient supplement of
blood, oxygen, and nutrients to the heart. Fractional Flow Reserve (FFR),
measuring the pressure ratio between the aorta and distal coronary artery, is
an invasive physiologic gold standard for assessing the severity of coronary
artery stenosis. Despite its benefits, invasive FFR assessment is still
underutilized due to its high cost, time-consuming, experimental variability,
and increased risk to patients. In this study, an attention-based
multi-fidelity machine learning model (AttMulFid) is proposed for
computationally efficient and accurate FFR assessment with uncertainty
measurement. Within AttMulFid, an autoencoder is utilized to intelligently
select geometric features from coronary arteries, with additional attention on
the key area. Results show that the geometric features are able to represent
the entirety of the geometric information and intelligently allocate attention
based on crucial properties of geometry. Furthermore, the AttMulFid is a
feasible approach for non-invasive, rapid, and accurate FFR assessment (with
0.002s/simulation)
Efects of non‑Newtonian viscosity on arterial and venous fow and transport
It is well known that blood exhibits non-Newtonian viscosity, but it is generally modeled as a Newtonian fluid. However, in situations of low shear rate, the validity of the Newtonian assumption is questionable. In this study, we investigated differences between Newtonian and non-Newtonian hemodynamic metrics such as velocity, vorticity, and wall shear stress. In addition, we investigated cardiovascular transport using two different approaches, Eulerian mass transport and Lagrangian particle tracking. Non-Newtonian solutions revealed important differences in both hemodynamic and transport metrics relative to the Newtonian model. Most notably for the hemodynamic metrics, in-plane velocity and vorticity were consistently larger in the Newtonian approximation for both arterial and venous flows. Conversely, wall shear stresses were larger for the non-Newtonian case for both the arterial and venous models. Our results also indicate that for the Lagrangian metrics, the history of accumulated shear was consistently larger for both arterial and venous flows in the Newtonian approximation. Lastly, our results also suggest that the Newtonian model produces larger near wall and luminal mass transport values compared to the non-Newtonian model, likely due to the increased vorticity and recirculation. These findings demonstrate the importance of accounting for non-Newtonian behavior in cardiovascular flows exhibiting significant regions of low shear rate and recirculation
Reconciling Speed Limits with Design Speeds
In recent years, context-sensitive highway design has been promoted to ensure that designers consider the environmental, scenic, aesthetic, historic, community, and preservation aspects of the road. Context-sensitive design may lead to situations where the current design standards cannot be met because of restricting local conditions. Indiana has road sections designed and built some time ago. In a considerable number of roads with the statutory limit of 55 mph (90 km/h), the road geometry does not meet the current standards. At individual intersections and on curves, advisory speeds are posted together with warning signs. Although this solution increases the safety of road users and allows for traveling at reasonably high speeds outside of these segments, the final solution is to upgrade their geometry to the desirable level. This report presents models that predict user-selected percentile free-flow speeds on two-lane rural and four-lane rural and suburban highways. The percentile speeds are computed as a linear combination of the mean speed and the standard deviation in panel data models with random effects. The developed percentile speed models involve more design variables than typical speed models, and separate the mean speed factors from the speed dispersion factors. These benefits ease the model interpretation and its use in highway design. The study results should help designers bring the predicted speed to the desired speed as close as possible given the budget constraints. Engineering judgment can then be applied to balance safety and construction cost in highway improvement projects
Volume filtered FEM-DEM framework for simulating particle-laden flows in complex geometries
We present a computational framework for modeling large-scale particle-laden
flows in complex domains with the goal of enabling simulations in medical-image
derived patient specific geometries. The framework is based on a
volume-filtered Eulerian-Lagrangian method that uses a finite element method
(FEM) to solve for the fluid phase coupled with a discrete element method (DEM)
for the particle phase, with varying levels of coupling between the phases. The
fluid phase is solved on a three-dimensional unstructured grid using a
stabilized FEM. The particle phase is modeled as rigid spheres and their motion
is calculated according to Newton's second law for translation and rotation. We
propose an efficient and conservative particle-fluid coupling scheme compatible
with the FEM basis that enables convergence under grid refinement of the
two-way coupling terms. Efficient algorithms for neighbor detection for
particle-particle collision and particle-wall collisions are adopted. The
method is applied to a few different test cases and the results are analyzed
qualitatively. The results demonstrate the capabilities of the implementation
and the potential of the method for simulating large-scale particle-laden flows
in complex geometries.Comment: 15 pages, 11 figure
Lesiones orales más frecuentes en pacientes edéntulos portadores de prótesis total.
A group of 210 patients with total maxillary and mandibular prostheses were examined to identify the main pathological alterations suffered by edentulous patients. The observed results determined that the average age at which the largest edentulous population is found is between 56 and 65 years with a higher prevalence of females. Of these more than 50% have used oral prostheses for more than 12 years with an adequate hygiene quality in 116 patients where the most frequent oral pathology associated with edentulism was fibrous hyperplasia (epulis), found in 19 patients, followed by stomatitis sub-prosthesis. Se examinó a 210 pacientes portadores de prótesis total maxilar y mandibular para identificar las principales alteraciones patológicas que padecen los pacientes edentulos. Los resultados observados determinaron que el promedio de edad donde se encuentra la mayor población edéntula ocurre entre los 56 y 65 años con una prevalencia mayor en el género femenino, de estos más del 50% han empleado prótesis bucales por más de 12 años con una calidad en la higiene adecuada en 116 pacientes donde la patología bucal más frecuente asociada al edentulismo fue la hiperplasia fibrosa (épulis) en 19 de ellos seguida por la estomatitis subprotésica
Perspectivas de las exportaciones de servicios en Chile
67 p.La investigación consiste en identificar, describir y analizar el entorno del comercio de servicios exportables de Chile. Para lo anterior se analizaran las exportaciones de servicios del periodo 1995 - 1998, según cifras arrojadas por el Banco Central de Chile en el ámbito nacional y regional, su tendencia en US$ FOB, por empresa, variedad de servicios y mercados de destino. De esta forma se podrá visualizar la participación que tiene este tipo de exportación a países, mercados y al bloque MERCOSUR. Quienes son los principales exportadores y cuales son los servicios que se exportan en mayor magnitud. Con el objeto de conocer la regulación del Comercio Internacional de Servicios, el trabajo abordara una descripción de la principal legislación existente y los cambios que se requieren para avanzar en su modernización del sector, si fuere necesario. Finalmente el trabajo aporta para cada subsector de servicios, sugerencias para mejorar y liberalizar el comercio de servicios
Proceso de certificación de infraestructura física educativa en el Estado de México, dentro del Programa Escuelas al Cien de la Secretaría de Educación
El programa de Escuelas al Cien fue una iniciativa del Gobierno Federal encabezado por el Lic. Enrique Peña Nieto y que tenía como objetivo: Mejorar las condiciones físicas y de equipamiento de las escuelas de educación básica. La operación del programa en la entidad, estuvo a cargo de la Secretaría de Educación Estatal, la cual tuvo que adoptar procesos de modernización en varias de sus áreas. Este trabajo aborda la temática relativa a esos cambios
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