STRUCTURAL DEVELOPMENTS IN THE MEXICAN LIVESTOCK SUBSECTOR: THE CASE OF FEEDER CATTLE AND BEEF PRODUCTION

Livestock Production/Industries,

Boundary-layer turbulence in experiments of quasi-Keplerian flows

Most flows in nature and engineering are turbulent because of their large velocities and spatial scales. Laboratory experiments of rotating quasi-Keplerian flows, for which the angular velocity decreases radially but the angular momentum increases, are however laminar at Reynolds numbers exceeding one million. This is in apparent contradiction to direct numerical simulations showing that in these experiments turbulence transition is triggered by the axial boundaries. We here show numerically that as the Reynolds number increases turbulence becomes progressively confined to the boundary layers and the flow in the bulk fully relaminarizes. Our findings support that turbulence is unlikely to occur in isothermal constant density quasi-Keplerian flows.Comment: 16 pages, 8 figures. Accepted for publication in Journal of Fluid Mechanic

Phase-field simulation of core-annular pipe flow

Phase-field methods have long been used to model the flow of immiscible fluids. Their ability to naturally capture interface topological changes is widely recognized, but their accuracy in simulating flows of real fluids in practical geometries is not established. We here quantitatively investigate the convergence of the phase-field method to the sharp-interface limit with simulations of two-phase pipe flow. We focus on core-annular flows, in which a highly viscous fluid is lubricated by a less viscous fluid, and validate our simulations with an analytic laminar solution, a formal linear stability analysis and also in the fully nonlinear regime. We demonstrate the ability of the phase-field method to accurately deal with non-rectangular geometry, strong advection, unsteady fluctuations and large viscosity contrast. We argue that phase-field methods are very promising for quantitatively studying moderately turbulent flows, especially at high concentrations of the disperse phase.Comment: Paper accepted for publication in International Journal of Multiphase Flo

Methods for Detection of Matrix Metalloproteinases as Biomarkers in Cardiovascular Disease

Matrix metalloproteinases (MMPs) are a family of zinc-dependent proteolytic enzymes that degrade extracellular matrix (ECM) components like collagen, fibronectin, and laminin. While this activity is important for normal development, morphogenesis, and wound healing, deregulation of MMP activity has been implicated in a number of cardiovascular diseases, including congenital heart defects, atherosclerosis, myocardial infarction, and congestive heart failure. MMPs are good potential diagnostic indicators of cardiovascular disease, but current detection methods are time consuming and quite laborious. This review will discuss MMP biology, current methods for detection of MMPs from patient samples, and potential new developments in multiplexed analysis of MMPs

Conductive and convective heat transfer in fluid flows between differentially heated and rotating cylinders

The flow of fluid confined between a heated rotating cylinder and a cooled stationary cylinder is a canonical experiment for the study of heat transfer in engineering. The theoretical treatment of this system is greatly simplified if the cylinders are assumed to be of infinite length or periodic in the axial direction, in which cases heat transfer occurs only through conduction as in a solid. We here investigate numerically heat transfer and the onset of turbulence in such flows by using both periodic and no-slip boundary conditions in the axial direction. We obtain a simple linear criterion that determines whether the infinite-cylinder assumption can be employed. The curvature of the cylinders enters this linear relationship through the slope and additive constant. For a given length-to-gap aspect ratio there is a critical Rayleigh number beyond which the laminar flow in the finite system is convective and so the behaviour is entirely different from the periodic case. The criterion does not depend on the Prandtl number and appears quite robust with respect to the Reynolds number. In particular, it continues to work reasonably in the turbulent regime.Comment: 25 pages, 9 figure

Review: The Role Of Hyperleptinemia In Chronic Degenerative Diseases

Leptin is a protein that belongs to the family of cytokines, it’s mainly produced by adipose tissue and its main function is to inform the nervous system about the amount of such tissue present in the organism, it also participates in the regulation of the neuroendocrine function and in the control of food intake; however, this molecule can also act in other tissues because their receptors are present in them. It has been identified that abnormal values of this protein can lead to have or aggravate some pathologies, such as cardiovascular, inflammatory, cancer, etc; since leptin is considered as a hormone that has proliferative, mitogenic, antiapoptotic and proinflammatory activity. Hyperleptinemia is a condition presented when leptin levels are above the normal level in the bloodstream (1-15 ng/ml) usually caused by physiological disorders such as obesity. Hyperleptinemia has been associated with several chronic degenerative diseases, where it has a strong relationship with the molecular basis of these diseases, either by direct action on the tissue or by its chemotactic ability to attract other molecules involved in the development of the disease. Because of these, abnormal levels of leptin in the body can be considered as a marker of disease, as described in this review

A bi-objective model for the integrated frequency-timetabling problem

The urban transport planning process has four basic activities: network design, timetable construction, vehicle scheduling and crew scheduling. In this work we focus on the urban bus timetable construction problem which has two sub-activities: bus frequency calculation and bus departures setting. Typically, these sub-activities are done sequentially, which has some drawbacks: to overcome these drawback we propose to integrate both these sub-activities. We take into consideration: multiple planning periods, synchronizations events (a synchronization occurs when two buses from different routes arrive to a node within a time window), fixed and variable operations costs and uncertain demand in each period

O PROCESSO DECISÓRIO EM UM CAMPUS DE UMA INSTITUIÇÃO DE ENSINO SUPERIOR DE SANTA CATARINA: UMA RELAÇÃO COM O DESENVOLVIMENTO ORGANIZACIONAL

O processo decisório é fundamental para a administração das organizações e mapear o perfil predominante de decisão possibilita o gerenciamento de melhorias a partir da análise de atitudes perante a gestão e seus resultados. Este artigo apresenta o perfil de tomada de decisão dos gestores de um campus de uma Instituição de Ensino Superior Pública e estabelecer uma relação com o desenvolvimento organizacional. Trata-se de um estudo de caso a partir de pesquisa aplicada, descritiva e com abordagens qualitativa e quantitativa. A coleta de dados foi através de questionários e sua análise resultou da interpretação de gráficos e das respostas das questões abertas. Os resultados obtidos mostraram o estilo de decisão predominante e as dificuldades encontradas no processo de tomada de decisão. Com isso ressalta-se a importância do estudo na área do processo decisório para que seja intensificada a busca pela missão desta instituição