Equilibrium dynamics in two-sector models of endogenous growth

This paper presents an account of the dynamics of endogenous growth models with physical capital and human capital. We consider some important extensions of the basic framework of Lucas (1988) and Uzawa (1964), including physical capital in the human capital technology and leisure activities as an additional argument of agents' welfare

A two-sector model of endogenous growth with leisure

In this paper we analyze a class of endogenous growth models with physical and human capital and with three altematives uses of time: unqualified leisure, work and education. In contrast to some other related models, we find that, even in the absence of technological extemalities, there could be multiple balanced paths. We provide a characterization of the qualitative behavior of consumption, leísure, work and education over those balanced paths, and study their transitional dynamics

Equilibrium dynamics in two-sector models of endogenous growth.

This paper presents an account of the dynamics of endogenous growth models with physical capital and human capital. We consider some important extensions of the basic framework of Lucas (1988) and Uzawa (1964), including physical capital in the human capital technology and leisure activities as an additional argument of agents' welfare.Endogenous growth; Physical capital; Human capital; Long-term growth; Transitional dynamics;

A two-sector model of endogenous growth with leisure.

In this paper we analyze a class of endogenous growth models with physical and human capital and with three altematives uses of time: unqualified leisure, work and education. In contrast to some other related models, we find that, even in the absence of technological extemalities, there could be multiple balanced paths. We provide a characterization of the qualitative behavior of consumption, leísure, work and education over those balanced paths, and study their transitional dynamics.

Active Exterior Cloaking

A new method of cloaking is presented. For two-dimensional quasistatics it is proven how a single active exterior cloaking device can be used to shield an object from surrounding fields, yet produce very small scattered fields. The problem is reduced to finding a polynomial which is approximately one within one disk and zero within a second disk, and such a polynomial is constructed. For the two-dimensional Helmholtz equation, it is numerically shown that three active exterior devices placed around the object suffice to produce very good cloaking.Comment: 4 pages, 3 figures, submitted to Physical Review Letter

Periodontal Inflammation and Its Relationship with the Risk of Cardiovascular Diseases: Literature Review

For dental practice today, it has become important to emphasize the relevance of periodontal inflammation and oral microorganisms in the development and progression of atherosclerosis and cardiovascular diseases. Generally, the focus on PI as a causal factor of CVD is due to the great complexity and interaction that present the Gram-negative bacteria characteristic of chronic periodontal disease with the vast vascularization of the stomatognathic system. In many recent studies, researchers examined the association at the cellular and molecular level between periodontal and cardiovascular diseases.  Although the specific causal correlation as a determining risk factor has not been established, it seems that periodontal disease is associated with several systemic diseases. In this connection, atherosclerosis is important in recent years. There is a possibility of an association documented in several field investigations, and this one refers to a systemic bacteremia caused by poor oral hygiene, which in turn can cause bacterial growth on the atherosclerotic plaques located in the coronary arteries, which possibly

Digestibility Coefficients and Energy in Alfalfa Hay from Chimborazo and Tungurahua

This study was part of a project (Grasas By Pass), funded by Ciencias Pecuarias ESPOCH. Samples from Chimborazo and Tungurahua were analyzed. The statistical analysis included descriptive analysis and significance tests, including Tukey test. The following results of ranges were found in the first phase: humidity: 7.79% (± 0.06) – 9.99% (± 0.08); ashes: 9.16% (± 0.14) – 10.50% (± 0.01); protein: 18.73% (± 0.10) – 21.37% (± 0.52); crude fiber: 31.64% (± 0.26) – 41.69% (± 0.11); ethereal extract: 1.36% (± 0.22) – 2.13% (± 0.50); and ELN: 28.30% (± 0.09) – 34.46% (± 0.24). The results from the second phase were: F.D.N.: 41.39% (± 1.32) – 51.77% (± 0.01); F.D.A.: 37.36% (± 0.26) – 45.47% (± 1.04); and L.D.A.: 7.85% (± 0.48) – 9.30% (± 0.39). In vivo digestibility tests were developed in metabolic cages with six sheep per treatment for 11 days. The following results were found: Dry matter digestibility coefficient (C.D.M.S.): 60.78% – 66.42%; organic matter (C.D.M.O.): 61.97% – 68.24%; protein (C.D.P.B.): 74.35% – 80.23%; crude fiber (C.D.F.C): 43.73% – 59.39%; ethereal extract (C.D.E.E.): 26.56% – 51.76%; and E.L.N. (C.D.ELN): 67.26% – 81.96%. Finally, the Van Es equations were applied to estimate the values of E.M., E.Nl., E.Ng. and N.D.T. The digestibility and energy coefficients for the hay from Chimborazo - San Juan were higher, and there were lower values for Tungurahua – Cunchibamba. Keywords: chemical composition, digestibility coefficient, useful energy. RESUMEN Como parte del proyecto financiado Grasas By Pass, de la Facultad de Ciencias Pecuarias ESPOCH; se analizaron muestras procedentes de Chimborazo y Tungurahua; el análisis estadístico incluyó análisis descriptivo y pruebas de significancia según Tukey P < 0.0001, en la primera etapa se realizó el análisis proximal que reportó rangos de: humedad 7,79% (±0,06)  –9,99% (±0,08), cenizas 9,16% (±0,14) – 10,50% (±0,01), proteína 18,73% (±0,10) – 21,37% (±0,52), fibra cruda 31,64% (±0,26) – 41,69% (±0,11), extracto etéreo 1,36% (±0,22) – 2,13% (±0,50) y E.L.N. 28,30% (±0,09) – 34,46% (±0,24). La segunda fase analizó: F.D.N.  con valores de 41,39% (±1,32)  –  51,77%(±0,01),  F.D.A.  37,36% (±0,26)  –  45,47% (±1,04)  y  L.D.A.  7,85% (±0,48)  – 9,30% (±0,39).  Se desarrolló las pruebas de digestibilidad In vivo en jaulas metabólicas con 6 ovinos por tratamiento durante 11 días, encontrándose rangos para el coeficiente de digestibilidad de la materia seca (C.D.M.S.) desde 60,78% – 66,42%; materia orgánica (C.D.M.O.) de 61,97% a 68,24%, proteína (C.D.P.B.) de 74,35% a 80,23%, fibra cruda (C.D.F.C) desde 43,73% hasta 59,39%, extracto etéreo (C.D.E.E.) 26,56% a 51,76%, y E.L.N. (C.D.ELN) desde 67,26% hasta 81,96%.  Finalmente se aplicó las ecuaciones de Van Es para estimar los valores de E.M., E.Nl., E.Ng. N.D.T. Siendo más elevados los coeficientes de digestibilidad y energía para los henos de Chimborazo - San Juan y valores más bajos para Tungurahua- Cunchibamba. Palabras claves: composición química, coeficiente de digestibilidad, energía útil

Evolution of an elliptical bubble in an accelerating extensional flow

Mathematical models that describe the dynamical behavior of a thin gas bubble embedded in a glass fiber during a fiber drawing process have been discussed and analyzed. The starting point for the mathematical modeling was the equations presented in [1] for a glass fiber with a hole undergoing extensional flow. These equations were reconsidered here with the additional reduction that the hole, i.e. the gas bubble, was thin as compared to the radius of the fiber and of finite extent. The primary model considered was one in which the mass of the gas inside the bubble was fixed. This fixed-mass model involved equations for the axial velocity and fiber radius, and equations for the radius of the bubble and the gas pressure inside the bubble. The model equations assumed that the temperature of the furnace of the drawing tower was known. The governing equations of the bubble are hyperbolic and predict that the bubble cannot extend beyond the limiting characteristics specified by the ends of the initial bubble shape. An analysis of pinch-off was performed, and it was found that pinch-off can occur, depending on the parameters of the model, due to surface tension when the bubble radius is small. In order to determine the evolution of a bubble, a numerical method of solution was presented. The method was used to study the evolution of two different initial bubble shapes, one convex and the other non-convex. Both initial bubble shapes had fore-aft symmetry, and it was found that the bubbles stretched and elongated severely during the drawing process. For the convex shape, fore-aft symmetry was lost in the middle of the drawing process, but the symmetry was re-gained by the end of the drawing tower. A small amount of pinch-off was observed at each end for this case, so that the final bubble length was slightly shorter than its theoretical maximum length. For the non-convex initial shape, pinch-off occurred in the middle of the bubble resulting in two bubbles by the end of the fiber draw. The two bubbles had different final pressures and did not have fore-aft symmetry. An extension of the fixed-mass model was considered in which the gas in the bubble was allowed to diffuse into the surrounding glass. The governing equations for this leaky-mass model were developed and manipulated into a form suitable for a numerical treatment