Burning Velocity of Turbulent Methane/Air Premixed Flames in Subatmospheric Environments.

The aim of our work was to study turbulent premixed flames in subatmospheric conditions. For this purpose, turbulent premixed flames of lean methane/air mixtures were stabilized in a nozzle-type Bunsen burner and analyzed using Schlieren visualization and image processing to calculate turbulent burning velocities by the mean-angle method. Moreover, hot-wire anemometer measurements were performed to characterize the turbulent aspects of the flow. The environmental conditions were 0.85 atm, 0.98 atm, and 295 ± 2 K. The turbulence-flame interaction was analyzed based on the geometric parameters combined with laminar flame properties (which were experimentally and numerically determined), integral length scale, and Kolmogorov length scale. Our results show that the effects of subatmospheric pressure on turbulent burning velocity are significant. The ratio between turbulent and laminar burning velocities increases with turbulence intensity, but this effect tends to decrease as the atmospheric pressure is reduced. We propose a general empirical correlation as a function between S T/S L and u'/S L based on the experimental results obtained in this study and the equivalence ratio and pressure we established.

Cómo motivar y motivarse en tiempos de crisis / No disponible

La motivación laboral constituye un tipo de comportamiento adaptativo con el que respondemos de manera eficaz a las demandas de nuestro trabajo. La crisis actual ha supuesto el cambio de algunas condiciones laborales básicas (horarios, retribución, seguridad, etc.) que están incidiendo en un tipo de motivación, determinada por condiciones externas al trabajador, que la investigación conoce es una motivación débil en intensidad y poco persistente en el tiempo. Propondremos algunas guías que se centran en el estímulo de motivaciones más autónomas y bajo el control del trabajador en base a investigaciones propias que hemos venido desarrollando en los últimos años. Gran parte de estas investigaciones se han basado en una comprensión dinámica de la motivación laboral. Entender la dinámica de la motivación nos aporta este tipo de guías útiles para la acción

Work motivation is an adaptive behavior that allow us to respond effectively to our job demands. The current crisis has introduced changes in some basic labour conditions (timetable, salary, security, etc.) that are affecting a type of motivation determined by external conditions of the worker. Research shows that this nonself-determined motivation is weaker in intensity and less persitent over time than the self-determined motivation. Based on the research we have been developing in recent years we propose some guidelines that focus on encouraging a more autonomous and self-determined motivation. Much of this research has been based on a dynamic understanding of work motivation. Understanding the dynamics of motivation gives us useful guides to action

Fluctuations in work motivation: tasks do not matter!

Previous studies have shown that work motivation fluctuates considerably and in a nonlinear way over time. In the present research, we are interested in studying if the task at hand does or does not influence the presence of these fluctuations. We gathered daily registers from 69 workers during 21 consecutive working days (7036 registers) of task developed and levels of motivation, self-efficacy beliefs and instrumentalities perception. These registers were then categorized into a list of labor activities in main tasks and subtasks by means of three judges with a high level of agreement (97.47% for tasks, and 98.64% for subtasks). Taking the MSSD statistic (mean squared successive difference) of the average of motivation, self-efficacy and instrumentality, and using hierarchical regression analysis we have found that tasks (beta = .03; p = .188) and subtasks (beta = .10; p = .268) do not affect the presence of fluctuations in motivation. These results reveal instability in work motivation independently from the tasks and subtasks that the workers do. We proceed to find that fluctuations in work motivation show a fractal structure across the different tasks we do in a working day. Implications of these results to motivational theory will be discussed as well as possible explanations (e.g. the influence of affect in work motivation) and directions for future research are provided.

Chaos in human behavior: the case of work motivation.

This study considers the complex dynamics of work motivation. Forty-eight employees completed a work-motivation diary several times per day over a period of four weeks. The obtained time series were analysed using different methodologies derived from chaos theory (i.e. recurrence plots, Lyapunov exponents, correlation dimension and surrogate data). Results showed chaotic dynamics in 75% of cases. The findings confirm the universality of chaotic behavior within human behavior, challenge some of the underlying assumptions on which work motivation theories are based, and suggest that chaos theory may offer useful and relevant information on how this process is managed within organizations.

Chaos in human behavior: the case of work motivation

This study considers the complex dynamics of work motivation. Forty-eight employees completed a work-motivation diary several times per day over a period of four weeks. The obtained time series were analysed using different methodologies derived from chaos theory (i.e. recurrence plots, Lyapunov exponents, correlation dimension and surrogate data). Results showed chaotic dynamics in 75% of cases. The findings confirm the universality of chaotic behavior within human behavior, challenge some of the underlying assumptions on which work motivation theories are based, and suggest that chaos theory may offer useful and relevant information on how this process is managed within organizations (AU)

Se realizó un estudio con el objetivo de explorar la posible dinámica caótica de la motivación en el trabajo. Cuarenta y ocho trabajadores contestaron un diario sobre su motivación en el trabajo varias veces al día durante cuatro semanas. Las series obtenidas fueron sometidas a diferentes técnicas de análisis no lineal derivadas de la teoría del caos (gráficos de recurrencia, exponentes de Lyapunov, dimensión de correlación y surrogate data). Los resultados mostraron dinámicas caóticas en un 75% de los casos. Ello confirma la universalidad del comportamiento caótico también dentro del comportamiento humano. Tales resultados cuestionan algunos de los supuestos fundamentales en los que se basan las teorías más establecidas y sugieren que la teoría del caos puede ofrecer información útil y relevante acerca de cómo gestionar la motivación en contextos laborales (AU)

[Variables related to the emergence of differential patterns in work motivation]. / Factores asociados a la emergencia de patrones diferenciales de la motivación en el trabajo.

Several longitudinal studies have shown that motivation at work acts chaotically. In very few cases, it may be linear or random. However, the factors that might explain why these different patterns emerge have not been analysed to date. In this exploratory study, we interviewed 73 employees whose motivational patterns were previously known. The results revealed that chaotic patterns were associated with high levels of motivation, self-efficacy beliefs, and perceptions of instrumentality, and also with intrinsic personal goal orientation and a perception of high work control. Linear patterns were associated with extrinsic goals and a perception of work as difficult, and random patterns were linked to high flexibility at work.

Factores asociados a la emergencia de patrones diferenciales de la motivación en el trabajo / Variables related to the emergence of differential patterns in work motivation

Diferentes investigaciones usando diseños longitudinales han logrado identificar que la motivación en el trabajo se comporta principalmente de forma caótica y excepcionalmente mostrando otro tipo de comportamientos (lineal o azaroso). Sin embargo, hasta el momento no se ha estudiado acerca de los factores explicativos de la emergencia de estos patrones distintos. Con el objetivo de afrontar esta cuestión, 73 trabajadores, cuyo patrón motivacional era conocido, fueron entrevistados con el fin de estudiar de manera exploratoria una serie de aspectos de su trabajo. Los resultados revelaron que el patrón caótico se asoció a altos valores de motivación, autoeficacia y percepción de instrumentalidad, orientación a metas personales intrínsecas y a una alta percepción de control sobre el trabajo. Frente a ellos el patrón lineal se asoció con metas extrínsecas y una percepción del trabajo como difícil y el patrón azaroso apareció asociado con una alta flexibilidad en el trabajo

Several longitudinal studies have shown that motivation at work acts chaotically. In very few cases, it may be linear or random. However, the factors that might explain why these different patterns emerge have not been analysed to date. In this exploratory study, we interviewed 73 employees whose motivational patterns were previously known. The results revealed that chaotic patterns were associated with high levels of motivation, self-efficacy beliefs, and perceptions of instrumentality, and also with intrinsic personal goal orientation and a perception of high work control. Linear patterns were associated with extrinsic goals and a perception of work as difficult, and random patterns were linked to high flexibility at work

An approach to the study of dynamics of work motivation using the diary method.

This study is concerned with work motivation as a dynamic process. Twenty workers kept a motivation diary over a period of several weeks. Using a PDA they recorded their level of motivation, self-efficacy beliefs and perceived instrumentality with respect to the task being carried out. The time series obtained were analyzed using common procedures in the study of dynamic systems in order to determine whether motivation followed linear or nonlinear patterns. The results revealed highly nonlinear dynamics for the different variables studied. The implications of these findings are discussed and questions are raised regarding the basic assumptions underlying current theories and models of motivation, for example, the assumptions of linearity and stability.

Factores de riesgo, incidencia y prevalencia de enfermedades cardiovasculares en una poblacion entre 25 y 70 años en la ciudad de Cartagena de Indias (Bolivar) / Factors of risk, incidence and prevalence of cardiovascular diseases in Cartagena de Indias population

Las enfermedades cardiovasculares son, en la actualidad, la primera causa de muerte y una de las principales causas de invalidez en los países occidentales. Este hecho ha coincidido con una serie de cambios en los hábitos que acompañan el proceso socioeconómico del desarrollo y que se relacionan directamente con el cambio de una sociedad tradicional agraria y rural a una sociedad en la que la mayoría de la población vive en los grandes centros urbanos y adopta los hábitos ligados a la sociedad industrial. Es destacable el alto grado de conocimiento del papel de los factores de riesgo por parte de la comunidad médica en general y de alguna parte de la población. En el presente estudio se ha confirmado el impacto que tienen los factores de riesgo tales como hipertensión arterial, dislipidemia, diabetes, obesidad, cardiopatías, tabaquismo, alcohol y drogas, sobre las enfermedades cardiovasculares específicamente en la población cartagenera de distintos estratos sociales, arrojando resultados sobre el tema que coinciden con la literatura mundial. Si se asocian varios factores de riesgo, la situación de riesgo global será más alta aunque por separado cada factor no demuestre mucha importancia. Controlando los factores de riesgo, en la población general y llevando políticas de prevención y atención primaria se podrán evitar eventos catastróficos en todos los pacientes que presenten dichos factores; en los individuos de alto riesgo son aplicables las recomendaciones generales de la población, si bien deben realizarse con una intensidad aún mayor, estas recomendaciones en forma general se exponen en el desarrollo del artículo