568 research outputs found
Entrepreneurship as Boundary Object: Toward Reintegration of Colombia’s Ex-Militants into Civil Society
War and other violent conflicts greatly degrade a country’s economic, social, and marketing systems. In the aftermath of conflict, national and international organizations develop different strategies, such as business development, aimed at the reconstruction of these systems. This article draws on boundary theory to frame the way in which entrepreneurship can help ex-militants to discard war-activities and to reintegrate peacefully and productively into a peace-time economy. An interpretive study examining the life-narratives of former militants of illegal groups involved in Colombia’s armed conflict – the world’s longest, lasting 52 years – regarding their business start-ups was designed and administered. Findings extend current Macromarketing and Entrepreneurship literature by showing how policies and entrepreneurial business practices in recovering marketing systems can help ex-militants to overcome discrimination, to transform their identities and to reintegrate peacefully into civil society, which in turn may portend a more inclusive and equitable marketing system and robust national economy
Caracterización limnológica de la laguna Salada de Chiprana (Zaragoza, España) y sus comunidades de bacterias fototróficas
Equivalent circuits for simulating irregular PV arrays under partial shading conditions
El modelado y simulación de sistemas fotovoltaicos (PV) son áreas de investigación abiertas ya que las curvas I-V y P-V son comúnmente requeridas para analizar el desempeño de instalaciones PV. Para obtener dichas curvas se pueden utilizar paquetes de cómputo, sin embargo, el tipo de conexión y el tamaño del arreglo PV pueden ocasionar largos tiempos de simulación. Para superar dicha dificultad se han propuesto técnicas basadas en los puntos de inflexión para modelar el arreglo PV con el objetivo de reconstruir exactamente las curvas eléctricas requeridas. Sin embargo, tal análisis ha sido aplicado solo a la configuración serie-paralelo (SP), la cual es solo una de las alternativas para conectar arreglos PV entre otras opciones de conexión regular o irregular. Por esto, se requiere una aproximación más general. Este artículo presenta una proximación para obtener las curvas características de cualquier arreglo PV, regular o irregular, extendiendo el análisis de los puntos de inflexión. Entonces, de las curvas eléctricas del arreglo PV es simplificado utilizando circuitos equivalentes en intervalos definidos por los puntos de inflexión. Tal procedimiento está basado en definir cuáles módulos se activan debido al comportamiento de los diodos de bypass. Finalmente, la aproximación propuesta permite analizar cualquier arreglo PV sin requerir de simulaciones largas. La solución fue validada por medio de resultados de simulación obtenidos en Matlab®.Modeling and simulation of photovoltaic (PV) systems are open research areas since I-V and P-V curves are commonly required to analyze the performance of PV installations. To obtain such curves commercial software packages can be used, however the connection type and size of the PV array may cause large simulation times. To overcome such an issue several techniques based on analyzing the inflection points have been proposed to model the PV array with the aim of reconstruct accurately the required electrical curves. However, such analysis has been applied only for series-parallel (SP) configuration, which is just one alternative to connect PV arrays among several other regular or irregular options. Therefore, a more general approach is needed. This paper presents an approach to obtain the characteristics curves for any PV array, regular or irregular, by extending the inflection points analysis. Then, the calculation of the PV array electrical curves is simplified by using equivalent circuits within the intervals defined by the inflection points. Such a procedure is based on defining which modules become active due to the behavior of the bypass diodes. Finally, the proposed approach enables to analyze any PV array without requiring long electrical simulations. The solution was validated by means of simulation results obtained in Matlab®
Search Space Calculation to Improve Parameter Estimation of Excitation Control Systems
En este artículo se presenta un método para calcular el espacio de búsqueda de cada parámetro del modelo de un sistema de control de excitación. Con el espacio de búsqueda calculado se pretende reducir el número de conjuntos de parámetros solución que pueden ser encontrados por el algoritmo de estimación, reduciendo su tiempo de procesamiento. El método considera un rango de la constante de tiempo del generador sincrónico entre 4s y 10s, un índice de desempeño del sistema de control de excitación, una técnica de diseño de controladores y la estructura del modelo del sistema de control de excitación. Cuando se usa el espacio de búsqueda obtenido para estimar los parámetros, el algoritmo toma menos tiempo de procesamiento y los parámetros estimados son cercanos a los parámetros de referencia.A method to calculate the search space for each parameter in an excitation control system is presented in this paper. The calculated search space is intended to reduce the number of parameter solution sets that can be found by an estimation algorithm, reducing its processing time. The method considers a synchronous generator time constant range between 4s and 10s, an excitation control system performance index, a controller design technique, and the excitation control system model structure. When the obtained search space is used to estimate the parameters, less processing time is used by the algorithm. Also the estimated parameters are closer to the reference ones
Biomasa de macrófitos acuáticos en la marisma del Parque Nacional de Doñana (SW España): importancia y factores ambientales que controlan su distribución
Floquet stability analysis of a two-layer oscillatory flow near a flexible wall
We investigate the linear Floquet stability of two fluid layers undergoing
oscillations in the direction parallel to the flexible wall that separates
them. This canonical configuration is inspired by the cerebrospinal fluid flow
in the spinal canal of subjects with hydro-/syringomyelia.The analysis focuses
on the marginal conditions for the onset of instability, and how these depend
on the spatial wavelength of the perturbation, and on the values of the control
parameters, which are the two channel widths, the Reynolds number, and the wall
stiffness. Unstable perturbations are found to oscillate synchronous with the
base flow. The wavelength of the most unstable perturbation, of the order of
the stroke length of the basic oscillatory motion, depends strongly on the wall
stiffness, but is only weakly influenced by the channel widths and the Reynolds
number. In general, around criticality, it was found that increasing the
Reynolds number has a destabilizing effect, and that decreasing the canal
widths stabilizes the instability. The wall stiffness on the other hand has a
non-monotonic effect, exhibiting an intermediate value for which the
instability is maximally amplified. The present analysis is a first step
towards a better understanding of the physical mechanisms that govern many
(bio)fluid mechanical problems that involve oscillatory flows near compliant
walls
Effects of empowering leadership under boundary conditions in the hospitality industry
This study tests the positive effects of empowering leadership (ELSH) under boundary conditions in the hospitality
industry. We propose the existence of an interactive process through which ELSH behaviors interact with
employees’ personality type to condition their engagement, which in turn influences their extra-role service
behavior. We use data from 294 employees and structural equation modeling. The results show that the interaction
of ELSH with employees’ independent and interdependent personality is negatively related to their
engagement. This decrease in engagement is then reflected in decreased extra-role service behaviors due to the
positive relationship between engagement and extra-role service. These findings suggest that self-construal is a
significant boundary condition capable of changing the positive relationship between ELSH and engagement to a
negative one. Not considering this relationship when establishing a leadership strategy such as ELSH in the
hospitality context could render efforts to achieve the goal of high-quality service ineffective.European Regional Development Fund (European Union)Spanish Government ECO2017-84138-PJunta de Andalucia A-SEJ-154-UGR18University of Granada/CBU
El directivo «acosado»: un estudio empírico de los factores individuales, organizativos y contextuales
The aim of this paper is to study the determinants of workplace bullying in a group of employees with a privileged position within the company: managers. First of all, we define the phenomenon. After we make a review of literature with the object to set related variables in a global model of workplace bullying. A sample population of 608 managers was obtained from the microdata file of the last European Working Conditions Survey (European Foundation for the Improvement of Living and Working Conditions). The methodology used to achieve our research objectives is based on the binary logistic regression model. With this statistical technique we determine the probability of the occurrence of an event –workplace bullying in this case– compared to the probability of the occurrence of the opposite event. The global model is integrated by individual, organizational and contextual factors and predicts the likelihood of workplace bullying in 68% (61,6% between bullied managers and 75,9% between non bullied managers). The resulting model for managers is similar to models of workplace bullying for employees in general.El objetivo del presente trabajo es estudiar los factores determinantes del acoso laboral que inciden en un colectivo de trabajadores con una situación privilegiada dentro de la empresa: los directivos. Tras delimitar conceptualmente el fenómeno, se realiza un recorrido sobre los hallazgos obtenidos a nivel empírico para establecer las variables presentes en un modelo global del acoso laboral. Con una submuestra aleatoria de 608 directivos y mandos intermedios obtenida de la última Encuesta Europea de Condiciones de Trabajo se estima, por etapas, un modelo de regresión logística binaria, para determinar la probabilidad de ocurrencia del acoso. El modelo global obtenido contiene variables a nivel individual, laboral-organizativas y contextuales y predice la probabilidad de acoso en un 68 por 100 (61,6% en directivos acosados y 73,9% en directivos no acosados), obteniéndose un modelo de acoso entre directivos muy similar al que se deduce de la literatura empírica analizada para todo tipo de trabajadores
Variable climate suitability for wheat blast (Magnaporthe oryzae pathotype Triticum) in Asia: results from a continental-scale modeling approach
Crop fungal diseases constitute a major cause of yield loss. The development of crop disease monitoring and forecasting tools is an important effort to aid farmers in adapting to climate variability and change. Recognizing weather as a main driver of fungal disease outbreaks, this work assesses the climate suitability for wheat blast (Magnaporthe oryzae pathotype Triticum, MoT) development in Asian wheat-producing countries. MOT was reported for the first time in Bangladesh in 2016 and could spread to other countries, provided that environmental conditions are suitable to spore development, distribution, and infection. With results from a generic infection model driven by air temperature and humidity, and motivated by the necessity to assess the potential distribution of MoT based on the response to weather drivers only, we quantify potential MOT infection events across Asia for the period 1980–2019. The results show a potential higher incidence of MOT in Bangladesh, Myanmar, and some areas of India, where the number of potential infection (NPI) events averaged up to 15 during wheat heading. Interannual trends show an increase in NPI over those three countries, which in turns show their higher interannual variability. Cold/dry conditions in countries such as Afghanistan and Pakistan appear to render them unlikely candidates for MOT establishment. The relationship between seasonal climate anomalies and NPI suggests a greater association with relative humidity than with temperature. These results could help to focus future efforts to develop management strategies where weather conditions are conducive for the establishment of MOT
Reconstrucción de defectos faríngeos
Reconstruction of pharyngeal defects continues to present a clinical challenge for the head and
neck surgeon. We have different reconstructive options to preserve speech, airway, and
swallowing functions. Reconstructive surgery implies a balance between oncologic cure, patient
morbidity, and quality of life.
Classical reconstructive techniques include pedicled cervical cutaneous or myocutaneous flaps
and distal myocutaneous flaps such as from the pectoralis major. Current microvascular techniqu
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