Reconceptualizar el constructo de oportunidad: una respuesta a un dilema teórico a través de una revisión sistemática de la literatura

After Shane’s seminal work in 2000 which highlighted the importance of entrepreneurial opportunities, the number of studies focusing on entrepreneurial opportunity increased rapidly. Different definitions of this concept were provided in the field, ranging from subjective to objective ones, which gave rise to a lack of consensus among researchers and this, in turn, was an obstacle that slowed down theorizing in entrepreneurship. Taking into account the past trends in management sciences, it seems to be the right moment to re-conceptualize the core construct of opportunity. The major critique of existing definitions is their operationalization. To provide a better operationalization, the present study aimed to offer a more accurate conceptual definition. To this end, the study first examined current debates on opportunity, which revealed the major problem causing the debates. Then, through a systematic literature review, from among more than seven thousand documents in the Scopus database containing opportunity keywords, 74 papers were selected following different phases of filtration. The papers were analyzed in detail to extract different constructs. Then, using the framework of Hansen et al, they were classified along six dimensions. The concepts under each dimension were examined to finally provide a bigger picture of the construct of opportunity and offer a re-conceptualization. The results of this study highlight the gaps for future research and pave the ground for other systematic literature reviews in the field.Después de que el influyente trabajo de Shane en 2000 destacó la importancia de las oportunidades empresariales, el número de estudios centrados en las oportunidades empresariales aumentó rápidamente. En el campo se aportaron distintas definiciones de este concepto, que van desde las subjetivas hasta las objetivas, lo que generó una falta de consenso entre los investigadores y esto, a su vez, fue un obstáculo que frenó la teorización en el emprendimiento. Teniendo en cuenta las tendencias pasadas en las ciencias de la administración, parece ser el momento adecuado para reconceptualizar el constructo central de la oportunidad. La principal crítica de las definiciones existentes es su operacionalización. Para brindar una mejor operacionalización, el presente estudio tuvo como objetivo ofrecer una definición conceptual más precisa. Con este fin, el estudio examinó en primer lugar los debates actuales sobre las oportunidades que revelaron el principal problema que suscitan los debates. Luego, mediante una revisión sistemática de la literatura, de entre más de siete mil documentos en la base de datos Scopus que contienen palabras clave de oportunidad, se seleccionaron 74 artículos siguiendo diferentes fases de filtración. Los artículos se analizaron en detalle para extraer diferentes constructos. Luego, utilizando el marco de Hansen et al, se clasificaron en seis dimensiones. Se examinaron los conceptos de cada dimensión para finalmente proporcionar una imagen más amplia del constructo de oportunidad y ofrecer una reconceptualización. Los resultados de este estudio destacan las brechas para futuras investigaciones y preparan el terreno para otras revisiones sistemáticas de la literatura en este campo

Correlation between CRP and IL-6 Serum Levels after Induction of Diabetes and Eight Weeks Resistance Training in Rats

Introduction: Systemic low-grade chronic inflammation is considered to be one of the significant characteristics of diabetes mellitus. This study aimed to investigate the correlation between C- reactive protein (CRP) and interleukin- 6 (IL-6) serum levels, after induction of diabetes and eight weeks of resistance training in rats. Methods: For the purpose of this experimental study, 24 streptozotocin induced diabetic rats were divided into three groups of 8 including (1) first week diabetic control, (2) last week diabetic control and (3) resistance training. Moreover, 8 healthy rats were chosen as the first week healthy control groups to assess the effects of diabetes induction on CRP and IL-6 serum levels. Rats of group 3 were subjected to an eight-week resistance training (3 days/week). Kolmogorov-Smirnov, independent-samples t-test, and Pearson correlation coefficient, were used for data analysis (p≤0.05). Results: Induction of diabetes had a significant effect on the increased serum levels of CRP (p = 0.01) and IL-6 (p = 0.01). However, after 8 weeks of resistance training, a significant decrease was observed in CRP (p = 0.001) and IL-6 (p = 0.01) serum levels of streptozotocin induced diabetic rats. Also, there was no significant correlation between CRP and IL-6 serum levels, after the induction of diabetes (p = 0.23) and eight weeks of resistance training (p=0.65). Conclusion: It appears that there is no correlation between CRP and IL-6 serum levels, after the induction of diabetes and eight weeks of resistance training in rats

Usage of date (phoenix dactylifera l.) seeds in human health and animal feed

This chapter outlines the applications of date seeds to health promotion and disease prevention. Epidemiological studies have consistently shown that high fruit and vegetable consumption is associated with a reduced risk of several chronic diseases, such as coronary heart disease, cardiovascular disease, cancers, atherosclerosis, neurodegenerative diseases (such as Parkinson and Alzheimer), and inflammation, as well as aging. This is attributed to the fact that these foods may provide an optimal mixture of phytochemicals such as dietary fiber; natural antioxidants such as vitamins C, E, and beta-carotene; and phenolic compounds. Date seed protein contains the majority of essential amino acids. Date seeds are a very rich source of dietary fiber, phenolics, and antioxidants that makes them a good ingredient for functional foods. Phenolic compounds of fruit seeds, such as phenolic acids and flavonoids, have been shown to possess many beneficial effects, including antioxidant, anticarcinogenic, antimicrobial, antimutagenic, and anti-inflammatory activities and the reduction of cardiovascular disease. The advantages of incorporating date seeds into the animal diet include increased weight gain, improved feed efficiency, and improved meat palatability. A few studies have reported allergy or hypersensitivity to date palm fruit and pollen. The high concentration of selenium detected in some date varieties, which is related to the selenium content of the soil, also gives some cause for concern

Influence of nanocatalyst on oxidative coupling, steam and dry reforming of methane: A short review

The influence of nanocatalyst on three main reactions for natural gas conversion such as steam reforming, dry reforming and oxidative coupling of methane has been reviewed with an emphasis on the literatures’ reports and results. Although literatures’ experimental results showed that the conversion of methane over the nanocatalysts was higher than that obtained from the ordinary catalysts, there was no correlation between the conversion of methane and the average sizes of the nanoparticles. The results of some nanocatalyst are also compared to ordinary catalysts in the literature which shows the improved influence of nanoscale catalyst performance on methane conversion