Mathematical Modeling of Blood Coagulation

Blood coagulation is a series of biochemical reactions that take place to form a blood clot. Abnormalities in coagulation, such as under-clotting or over- clotting, can lead to significant blood loss, cardiac arrest, damage to vital organs, or even death. Thus, understanding quantitatively how blood coagulation works is important in informing clinical decisions about treating deficiencies and disorders. Quantifying blood coagulation is possible through mathematical modeling. This review presents different mathematical models that have been developed in the past 30 years to describe the biochemistry, biophysics, and clinical applications of blood coagulation research. This review includes the strengths and limitations of models, as well as suggestions for future work

Minimal tori with low nullity

AbstractThe nullity of a minimal submanifold M⊂Sn is the dimension of the nullspace of the second variation of the area functional. That space contains as a subspace the effect of the group of rigid motions SO(n+1) of the ambient space, modulo those motions which preserve M, whose dimension is the Killing nullity kn(M) of M. In the case of 2-dimensional tori M in S3, there is an additional naturally-defined 2-dimensional subspace that contributes to the nullity; the dimension of the sum of the action of the rigid motions and this space is the natural nullity nnt(M). In this paper we will study minimal tori in S3 with natural nullity less than 8. We construct minimal immersions of the plane R2 in S3 that contain all possible examples of tori with nnt(M)<8. We prove that the examples of Lawson and Hsiang with kn(M)=5 also have nnt(M)=5, and we prove that if the nnt(M)⩽6 then the group of isometries of M is not trivial

Funciones de producción y eficiencia técnica en el eje cafetero colombiano: una aproximación con frontera estocástica

Este estudio estimó la forma funcional de producción cafetera en Colombia mediante fronteras estocásticas (FEP). Con esto, se analizó la importancia de los principales insumos empleados en la producción de café (cantidad de hectáreas cultivadas, mano de obra utilizada, maquinaria requerida y cantidad de fertilizantes aplicados), que afectan la productividad. Igualmente, se determinó la existencia de economías a escala en productores pequeños, medianos, grandes y sector general cafetero; ubicados en Caldas, Quindío y Risaralda. Finalmente, fue evaluada la eficiencia técnica (ET) en la producción. Entre los principales resultados, se destaca que la función de producción cafetera tiene una forma funcional Translog minflex Laurent para pequeños, medianos, grandes y sector general del eje cafetero colombiano. Así, para pequeños, medianos y sector general de cafeteros existe ineficiencia técnica y estocástica en la actividad agrícola; caso contrario, en grandes que son eficientes técnicamente aunque no estocásticamente. Por consiguiente, la medida de eficiencia técnica obtenida mediante FEP, indica que el promedio de rendimiento para el sector general es de 70%, en pequeños 70%, medianos 66% y grandes del 99%. Dada la heterogeneidad, en la producción de café, los pequeños, medianos y sector general de caficultores presentan rendimientos crecientes a escala, mientras los grandes cafeteros exhiben rendimientos decrecientes a escala; en el eje cafetero colombiano. De acuerdo con estos resultados, el insumo más importante en el sector cafetero, unidades medianas y pequeñas es el área productiva en café, mientras para los grandes es la mano de obra empleada en el cultivo.función de producción cafetera, pequeños caficultores, medianos caficultores, grandes caficultores y sector general cafetero, frontera estocástica de producción, eficiencia técnica, análisis de economías a escala., Crop Production/Industries, Q12, D24, C01, C29,

Simulating chemistry using quantum computers

The difficulty of simulating quantum systems, well-known to quantum chemists, prompted the idea of quantum computation. One can avoid the steep scaling associated with the exact simulation of increasingly large quantum systems on conventional computers, by mapping the quantum system to another, more controllable one. In this review, we discuss to what extent the ideas in quantum computation, now a well-established field, have been applied to chemical problems. We describe algorithms that achieve significant advantages for the electronic-structure problem, the simulation of chemical dynamics, protein folding, and other tasks. Although theory is still ahead of experiment, we outline recent advances that have led to the first chemical calculations on small quantum information processors.Comment: 27 pages. Submitted to Ann. Rev. Phys. Che

A new combined quasigeoid model in Tierra del Fuego

This work focuses on the development of a combined quasigeoid model for Tierra del Fuego province. The Equivalent Source Technique (EST) is applied together with the remove-compute-restore technique in order to combine gravity and GPS/levelling observations and to obtain a quasigeoid model. This model features an improved accuracy in relation to previous models. A discussion about the geodetic reference system is also presented. Geodetic coordinates of all stations used were transformed to TDF08 to be in accordance with the new geodetic reference frame of Argentina. After a cross validation procedure it is determined that a 5cm (r.m.s.) quasigeoid model has been achieved for the major part of the province, fulfilling the requirements for its practical use. New Global Geopotential Models (GGM) are introduced in the discussion, particularly the EGM2008 which is used for evaluation purposes. It shows a 9cm agreement after its evaluation on the levelling lines

La l?dica como estrategia pedag?gica para el fortalecimiento del aprendizaje significativo en los ni?os del grado preescolar del centro educativo Maranatha

137 p. Recurso Electr?nicoEl presente documento da cuenta del trabajo de investigaci?n formativa realizado en el Centro Educativo Maranatha de la comuna dos de la ciudad de Ibagu?, el cual involucra el estudio cualitativo, de enfoque etnogr?fico, desarrollado en dos fases: en la primera se realiz? un ejercicio de caracterizaci?n, donde se reconoce el contexto que rodea a los ni?os de grado preescolar utilizando diversas t?cnicas e instrumentos tales como cuestionarios, entrevistas, observaci?n (participante y no participante), indagaci?n documental, diarios de campo, entre otras; evidenciando de esta manera una problem?tica susceptible de ser intervenida para su mejoramiento. En la segunda fase, se realiza la intervenci?n de la problem?tica detectada, est? se realiza mediante el Proyecto Pedag?gico de Aula ?Juego, me divierto y aprendo? el cual involucra a los estudiantes, docentes, directivos y padres de familia del grado preescolar; dicha intervenci?n se realiza mediante actividades integradoras dirigidas a cada uno de los agentes educativos. El Proyecto Pedag?gico de Aula implementado se basa principalmente en el desarrollo de estrategias l?dico-pedag?gicas, las cuales crean un ambiente de alegr?a y disfrute frente al proceso de formaci?n infantil, promoviendo as? el fortalecimiento del aprendizaje significativo en los ni?os, generando la dinamizaci?n del trabajo de aula, haci?ndolos protagonistas de su formaci?n, buscando el mejoramiento del proceso de ense?anzaaprendizaje sin incurrir en la rutina obligada del modelo tradicional. Palabras claves: L?dica, aprendizaje significativo, estrategias pedag?gicas, dinamismo.The following document provides a detail report of the formative research held in Maranatha Primary School, located in the second commune of Ibague, which involves a qualitative study with an ethnographic approach, developed in two stages: in the first one there was a characterization where the researchers recognized the context that surrounded the kindergarten students using several techniques and instruments such a questionnaires, interviews, observational study (participant and non-participant), documentary inquiry, field dairy, among others; it evidences that there is a problematic eligible for intervention and further improvement. In the second stage, there is an intervention of the problems identified, it is held through the Classroom Pedagogical Project: ?I play, have fun and learn? which involves students, teachers, managers and parents in kindergarten; such intervention is carried out by taking into account inclusive activities directed to each educative agent. The Classroom Pedagogical Project, after been implemented, is mainly based on the development of playful-pedagogical strategies, which create a funny and joyful environment towards the early childhood education process, promoting in this way the consolidation of the meaningful learning in children, this in turn stimulates classwork, making us play the major role in the teaching-learning process without incurring into the traditional model routine. Keywords: playful, meaningful learning, pedagogical strategies, dynamism

Estudio comparativo de dos métodos de radiografías forzadas para detectar la insuficiencia del ligamento cruzado anterior

En 32 pacientes con rotura unilateral de ligamento cruzado anterior (LCA) comprobada mediante artroscopia se efectuó previamente una radiografía forzada de ambas rodillas para estudiar el desplazamiento anterior de la tibia. Cada paciente fue estudiado mediante dos métodos diferentes, Lachman activo radiológico (LAR) y TelosR. Se asumió el diagnóstico radiológico de inestabilidad cuando la diferencia en el desplazamiento entre la rodilla lesionada y su control fue superior a 3 mm. Los resultados demuestran que la diferencia media del desplazamiento entre la rodilla lesionada y la normal fue superior a 3 mm con ambos métodos. En el lado interno 3,7 ± 3,7 mm con el LAR y 4,8 ± 5,8 mm con el Telos (diferencias no significativas). En el lado externo esta diferencia fue de 4,3 ± 4,7 nun con el LAR y de 6,8 ± 6 mm con el Telos (p < 0,05). A pesar de estos resultados, ambos métodos mostraron una sensibilidad para la detección de la insuficiencia ligamentosa inferior al 70%, lo que cuestiona su valor para el diagnóstico de la misma.In a prospective study, 32 patients with arthroscopically proved anterior cruciate ligament rupture were previously stressradiographied on both knees through two methods: the quadriceps-contraction technique (QCT) and the TelosR device. Instability was assumed when radiological differential displacement between injured and normal knee was greated than 3 mm. Results showed that this differential displacement was greater than 3 mm with both methods: 3,7 ± 3,7 mm v.s. 4,8 ± 5,8 mm in the medial side (differences not significant) and 4,3 ± 4,7 mm v.s. 6,8 ± 6 mm (p < 0.05) for the lateral side with the QCT and TelosR respectively. In spite of these differences, both methods showed a sensitivity lower than 70%

Towards a tidal loading model for the Argentine-German Geodetic Observatory (La Plata)

We present a regionalized model of ocean tidal loading effects for the Argentine-German Geodetic Observatory in La Plata. It provides the amplitudes and phases of gravity variations and vertical deformation for nine tidal constituents to be applied as corrections to the observatory’s future geodetic observation data. This model combines a global ocean tide model with a model of the tides in the Río de la Plata estuary. A comparison with conventional predictions based only on the global ocean tide model reveals the importance of the incorporation of the regional tide model. Tidal loading at the observatory is dominated by the tides in the Atlantic Ocean. An additional contribution of local tidal loading in channels and groundwater is examined. The magnitude of the tidal loading is also reviewed in the context of the effects of solid earth tides, atmospheric loading and non-tidal loadsFacultad de Ciencias Naturales y Muse