341 research outputs found
Corruption and entrepreneurship: A bibliometric analysis
The impact of corruption on entrepreneurial dynamics became an attractive topic for scholars after the appearance of public scandals that led to the delegitimization of many governments in the last 40 years. The research that explored the relationship between corruption and entrepreneurship has produced controversial results. It appears that the interaction of these two constructs is influenced by contextual factors both at an individual and national level of analysis. By using a bibliometric methodology and a fractional counting method to analyse the scientific literature on corruption and entrepreneurship, this paper identifies and analyses 180 articles recorded in the Scopus database. It represents a contribution by showing the state of the art of research on corruption and entrepreneurship and proposes future lines of research. Important results have been found about the evolution of the volume of articles and citations on this topic over time. Significant academic interest in this field commenced in the 21st century, and more specifically in the last ten years. This work also provides findings about the most prolific journals, institutions and authors, as well as the most relevant countries, with the United States and United Kingdom leading in terms of the number of publications. In addition, an in-depth analysis of authors' keywords has identified different trends, such as institutions, economic growth, shadow economy, regulation, Africa, culture, economic development, business environment, and informal economy. Finally, some future research lines are proposed, such as institutional theory, tax morale, corruption perceptions, European regions, risk aversion and institutional entrepreneurship
Procesos de alteración de materiales pétreos en edificios de interés histórico
This is a general survey of the different stages in the technicaldiagnostic activities carried out at present on the conservation state of monuments previous to restoration.Diagnostic studies are commonly hased on the effects of pollution (external factor), and on the study of rock porosity and its hydric properties (interna1 factors). Other alteration processes may also be caused by the mineralogical nature, as well as the crystallochemical characteristics of the rock. These mechanisms may be determinig factors that can go unnoticed if no in-depth petroiogicai and crystallochemical studies are carried out, especially those using the new techniques of electron microscopy and electron drilling.Here a rock of Miocenic age from the " Covas del Llorito" near Tarragona quarries is described. This partially dolomitized calcisiltite presents a zoned idiotypic fabric, with an anomalous intracrystalline distribution of calcium and magnesium, non-stechiomehic and deficient in magnesium. These crystalls undergo a differential disolution of their nuclei, wich produces abundan1 intracrystalline moldic porosity, and subsequent disaggregation and the formation of sand. This predisposition to alteration, of diagenetic origin, is speeded up by existing gypsum efflorescences, external to the rock
Entrepreneurship and psychological disorders in academic publishing
The role that different psychological disorders play in entrepreneurial intentions and behaviors is of increasing interest and importance to the scientific community. Scholars have undertaken a range of investigations that demonstrate that individuals with specific psychological disorders should be treated differently to other individuals. Some studies contribute to psychological disorders shifting from a disability paradigm to a paradigm of diversity. The main objective of this work is to carry out a preliminary analysis of the literature published about the relationship between psychological disorders and entrepreneurship. For this purpose, a bibliometric methodology and a fractional counting method of clustering were developed, identifying and analyzing 108 documents as recorded in the Web of Science and Scopus databases on the relationship between entrepreneurship and psychological disorders. This paper represents a contribution to the state-of-the-art of research on entrepreneurship and psychological disorders, identifying trends and proposing future topics and research lines
Valoración clínica de resultados en artrodesis trapecio-metacarpiana: placa atornillada vs agujas de Kirschner
La rizartrosis es una patología frecuente. Cuando el tratamiento conservador es insuficiente, se indica
un tratamiento quirúrgico. Existen diversas técnicas, entre las más ampliamente utilizadas está la artrodesis trapeciometacarpiana.
Realizamos un estudio retrospectivo 44 casos (57 intervenciones) comparando dos métodos de
artrodesis, agujas de Kirschner y placas atornilladas. Se realizó una valoración radiológica, clínica y funcional de los
casos para determinar las posibles ventajas de un método sobre otro. La edad media fue 56,5 5,9 años. Se utilizaron
33 agujas Kirschner, 24 placas atornilladas. Mejoría en los resultados de los cuestionarios EVA (4,8 3,4) y DASH
(23,2 23,5). El 44,7% movilidad con escala de Kapandji de 10. Se analizaron estadísticamente los datos, no encontrando
diferencias significativas entre los dos métodos en cuanto a la consolidación, estado funcional ni complicaciones.
En la mayor parte de los casos la clínica disminuye, se mejora la función con una excelente satisfacción del
paciente. No hemos encontrado diferencias en nuestro estudio en las variables observadas.Trapezio-metacarpal arthritis is common. In that cases in which has failed to respond to conservative
measures we need to use surgical procedures. One of them is the trapeziometacarpal arthrodesis. Retrospectiv
study 44 patients (57 arthrodeses), comparing two surgical arthrodesis procedures, K-wires versus plate and screws,
to assess the efficacy of these procedures with respect to patient satisfaction, radiological and clinical outcomes. Average
age was 56.5 5.9 years. 33 K-wires, 24 plate and screws. There were an improvement in quetionaires results VAS
(4.8 3.4) and DASH (23.2 23.5). The 44.7 % of patients scored a 10 in Kapandji test. We found no statistical differencees
between these procedures in non-union rate, functional outcome or complications. For most patients Trapeziometacarpal
arthrodesis reduces pain, improves function and results in excellent patient satisfaction. We have found
no differences between these procedures in our study
Comportamiento en conservación de cultivares de manzana ‘Reineta del Canadá’
Apple (Malus domestica Borkh) cultivars ‘Reinette du Canada’ (RC) and ‘Reinette Grise du Canada’ (RG) have been declared throughout the European Community as protected designation of origin (PDO) ‘Manzana Reineta del Bierzo’. The aim of this research was to find out the influence of storage technique on quality of PDO apple cultivars ‘RC’ and ‘RG’, and to evaluate the absence of traditional post-harvest treatments in these high quality cultivars in order to reduce pesticide residues in fruit. Apples were kept in standard cold storage or in controlled atmosphere (CA). At harvest time and during storage, fruit from each treatment and storage technique was analysed to determine quality parameters as well as disorder incidence. CA storage has been useful to delay the maturity process of PDO apple cultivars ‘RC’ and ‘RG’ and to reduce the incidence of storage disorders. Apple cultivars had different behaviour so ‘RG’ cultivar showed lower weight loss (5.1%), shrivelling (6.4%) and bitter-pit (11%) than ‘RC’ cultivar (8.3%, 60.8% and 34%, respectively) at the end of storage. The response of both cultivars to the treatment was quite different, so ‘RG’ adapted better than ‘RC’ to the absence of postharvest treatments. Untreated ‘RG’ showed more brightness, total soluble solids (TSS) and TSS:titratable acidity values than treated ‘RG’, factors that could improve consumer acceptance. Effectiveness of postharvest treatment in terms of bitter-pit was lower in ‘RG’ than in ‘RC’. These results indicate that ‘RG’ would adapt better to storage without the use of chemical postharvest treatments.Los cultivares de manzana (Malus domestica Borkh) ‘Reineta del Canadá’ (RC) y ‘Reineta Gris del Canadá’ (RG) han sido declarados en la Unión Europea como Denominación de Origen Protegida (DOP) ‘Manzana Reineta del Bierzo’. El objetivo de este trabajo fue averiguar la influencia de la técnica de conservación en la calidad de los cultivares de la DOP ‘Manzana Reineta del Bierzo’, ‘RC’ y ‘RG’, así como evaluar la ausencia de los tradicionales tratamientos postcosecha en estos cultivares de alta calidad con objeto de reducir los residuos finales en el fruto. Las manzanas fueron almacenadas en frío normal o en atmósfera controlada. En recolección y durante la conservación frigorífica se determinaron los parámetros de calidad y la incidencia de enfermedades. La técnica de atmósfera controlada fue útil para retrasar la maduración de los cultivares DOP ‘Manzana Reineta del Bierzo’ ‘RC’ and ‘RG’ y para reducir la incidencia de alteraciones durante conservación. Los cultivares tuvieron diferente comportamiento, de manera que ‘RG’ mostró menor pérdida de peso (5.1%), arrugamiento (6.4%) y bitter-pit (11%) que ‘RC’ (8.3%, 60.8% y 34%, respectivamente) al final de la conservación. La respuesta de los cultivares ante el tratamiento fue diferente, pues ‘RG’ se adaptó mejor que ‘RC’ a la ausencia de tratamientos. ‘RG’ no tratada mostró mayor brillo, sólidos solubles totales (TSS) y TSS:Acidez titulable que ‘RG’ tratada, lo cual podría aumentar la aceptación por parte del consumidor. La eficacia de los tratamientos postcosecha en el control de bitter-pit fue menor en ‘RG’ que en ‘RC’. Estos resultados indicarían que ‘RG’ se adaptaría mejor a una conservación sin tratamientos químicos postcosecha
Use of 3-aminotriazole to isolate oleate/acetate non-utilizing mutants of Aspergillus nidulans
Oleate non-utilizing (olu) mutants of Aspergillus nidulans were isolated on selective medium containing the catalase inhibitor, 3-aminotriazole (3-AT); in an attempt to obtain strains that would enable analysis of peroxisome biogenesis and function in filamentous fungi. Out of 816 putative mutants recovered from the selective medium, 40 were olu mutants. All of the olu mutants were unable to utilize acetate for growth, and so ressembled the acu mutants obtained by previous workers. The 40 olu mutants were placed in 5 different complementation groups
The exceptionally high diversity of small carnivorans from the Late Miocene hominid locality of Hammerschmiede (Bavaria, Germany)
The present study deals with new material of carnivorans (Mustelidae, Mephitidae, Ailuridae, Potamotheriinae and Viverridae) from the basal Tortonian (Late Miocene, late Astaracian) hominid-bearing locality of Hammerschmiede (Bavaria, Germany). The small carnivoran fauna includes 20 species belonging to nine different subfamilies (Guloninae, Lutrinae, Mellivorinae, Potamotheriinae, Leptarctinae, Mephitinae, Simocyoninae, Genettinae and Viverrinae). The identified forms include: “Martes” sansaniensis, “Martes” cf. munki, “Martes” sp., Circamustela hartmanni n. sp., Laphyctis mustelinus, Guloninae indet., Eomellivora moralesi, Vishnuonyx neptuni, Paralutra jaegeri, Lartetictis cf. dubia, Trocharion albanense, Palaeomeles pachecoi, Proputorius sansaniensis, Proputorius pusillus, Alopecocyon goeriachensis, Simocyoninae indet., Potamotherium sp., Semigenetta sansaniensis, Semigenetta grandis and Viverrictis modica. The new species Circamustela hartmanni n. sp. is differentiated from the other members of the genus by its small size and the morphology of its dental cusps in the upper and lower carnassials. This is one of the highest reported taxonomic diversities for fossil small carnivorans in the Miocene of Europe, including also first and last occurrences for several genera and species. Additionally, the assemblage comprises some rare taxa such as Palaeomeles pachecoi and Eomellivora moralesi. An ecomorphological comparison of the discovered taxa reveals possible cases of competition and niche partitioning. © 2022 Kargopoulos et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
Variabilidad de la actividad física en adolescentes españoles de 17-18 años en función del tipo de jornada y época del año
El objetivo de este estudio fue analizar la variabilidad de los niveles de actividad física de una muestra de 395 adolescentes españoles de 17-18 años, según la estación del año (otoño, invierno) y el tipo de jornada (entre semana, fin de semana). La medida de la actividad física se llevó a cabo a través del cuestionario de recuerdo Four by one-day physical activity questionnaire. Los adolescentes presentaron mayor gasto energético en invierno (M = 39.97 Kcal/kg/día) que en otoño (M = 37.31 Kcal/kg/día), y en fin de semana (M = 39.29 Kcal/kg/día) que en jornada escolar (M = 37.99 Kcal/kg/día). Las pruebas Chi-cuadrado muestran que hay más adolescentes 'activos' y 'moderadamente activos' en estos periodos en los que también hay mayor gasto energético. No obstante, en otoño los jóvenes presentaron mayor gasto energético durante la jornada escolar (M = 38.56 Kcal/kg/día) que en fin de semana (M = 36.06 Kcal/kg/día), mientras que en invierno ocurrió lo contrario (M = 42.52 Kcal/kg/día en fin de semana y M = 37.41 Kcal/kg/día durante la jornada escolar). Los resultados de este estudio indican que la estación del año y el tipo de jornada pueden afectar a los niveles de actividad física de los adolescentes, pero de modo distinto en comparación con otros países o zonas geográficas. En función de esta variabilidad particular, se plantean diversas estrategias para la promoción de la actividad física en los periodos más inactivos de la semana y el año.The aim of this study was to analyze the variability of physical activity levels, according to the season (winter, autumn) and type of day (weekend, school day), in a sample of 395 Spanish adolescents aged 17-18 years old. Physical activity was measured with the Four by one-day physical activity questionnaire. Adolescents showed more energy expenditure in winter (M = 39.97 Kcal/kg/day) than in autumn (M = 37.31 Kcal/kg/day), and during the weekend (M = 39.29 Kcal/kg/day) than the school day (M = 37.99 Kcal/kg/day). Chi-square tests showed that more teens were 'active' and 'moderately active' in these periods in which there were also more energy expenditure. Nevertheless, in autumn adolescents showed more energy expenditure during the school day (M = 38.56 Kcal/kg/day) than the weekend (M = 36.06 Kcal/kg/day), while the opposite happened in winter (M =42.52 Kcal/kg/day during weekend and M = 37.41 Kcal/kg/day during school day). Results from this study indicate season and type of day may influence adolescents' physical activity levels, but differently compared to other countries or geographical areas. According to this specific variability, several strategies for the promotion of physical activity in the most inactive periods of the week and the year are suggested.O objectivo deste estudo foi analisar a variabilidade dos níveis de actividade física de uma amostra de 395 adolescentes espanhóis de 17-18 anos, segundo a estação do ano (outono, inverno) e o tipo de dia (durante a semana, fim-de-semana). A medida de actividade física foi levada a cabo através do questionário retrospectivo, Four by one-day physical activity questionnaire. Os adolescentes apresentaram maior gasto energético no inverno (M = 39.97 Kcal/kg/dia) que no outono (M = 37.31 Kcal/kg/dia), e no fim-de-semana (M = 39.29 Kcal/kg/dia) que num dia escolar (M = 37.99 Kcal/kg/dia). Os testes de Qui-Quadrado mostram que existem mais adolescentes "activos" e "moderadamente activos" nestes períodos onde também há mais gasto energético. Não obstante, no outono os jovens revelaram maior gasto energético durante um dia escolar (M = 38.56 Kcal/kg/dia) que no fim-de-semana (M= 36.06 Kcal/kg/dia), enquanto que no inverno se verificou o oposto (M= 42.52 Kcal/kg/dia no fim-de-semana e M= 37.41 Kcal/kg/dia durante um dia escolar). Os resultados deste estudo indicam que a estação do ano e o tipo de dia podem afectar os níveis de actividade física dos adolescentes, mas não de forma distinta comparativamente com outros países e zonas geográficas. Em função desta variabilidade particular, sugeremse diversas estratégias para a promoção da actividade física nos períodos de maior inactividade da semana ou do ano
New route to pyrido[1,2-b]pyridazinium inner salts. Evidence of a 1,3-dipolar cycloaddition-ring expansion process
2-Alkoxycarbonylpyridinium N-aminides behave as 1,3-dipoles when reacted with Michael accepters, giving rise to the corresponding cycloadducts which, depending on their regioisomeric nature, subsequently undergo a ring expansion to give pyrido[1,2-b]pyridazinium inner salts.We wish to express our thanks to the Comisión Interministerial de Ciencia y Tecnología (CICYT, project PM97-004) and to the Ministerio de Educación y Ciencia for a grant to one of
us (J.V.M)
Muerte neural temprana: un proceso inadvertido en el desarrollo del sistema nervioso.
15 p.-7 fig.[EN]During the development of the vertebrate nervous system, multiple physiological
processes are involved in the generation of its complex cytoarchitecture and
functionality. Among them, programmed cell death has been recognized as a key
process that affects connecting neurons. By contrast, there is limited information
available regarding the cell death that affects neuroepithelial cells, and recently
born neurons and glia, hindering the comprehensive understanding of neural
development. We have demonstrated that exquisitely regulated PCD occurs during
early stages of neural development such as neurulation and neurogenesis. We have
characterized how survival signals from proteins like proinsulin/insulin, c-Raf, and
HSC70 counteract caspase-dependent apoptosis, which affects neuroepithelial cells
proliferation and the generation of retinal ganglion cells. Furthermore, the characterization of these physiological signals during retinal neurogenesis has the
potential to provide new therapeutic tools to attenuate retinal neurodegeneration.[ES]Durante el desarrollo del sistema nervioso de vertebrados, múltiples procesos fisiológicos participan en la generación de su compleja arquitectura celular y funcionalidad. Entre ellos, la muerte celular programada que afecta a neuronas de conexión está reconocido como un proceso fundamental. Por otro lado, hay escasa información disponible acerca de la muerte celular que afecta a células neuroepiteliales y a neuronas y glía recién nacidas, lo que impide que tengamos una noción completa sobre el desarrollo neural. Los estudios de nuestro laboratorio han demostrado que la muerte celular programada se encuentra finamente regulada y ocurre en etapas tan tempranas del desarrollo como la neurulación o la neurogénesis. Hemos caracterizado el papel que moléculas de supervivencia, como la proinsulina/insulina, c-Raf o HSC70, desempeñan bloqueando la apoptosis dependiente de caspasas, proceso que afecta a células neuroepiteliales proliferativas, así como a la generación de las células ganglionares de la retina. Es más, la caracterización de estas señales fisiológicas originadas durante la neurogénesis de la retina nos ha proporcionado una nueva herramienta terapéutica potencial para el tratamiento y atenuación de las neurodegeneraciones retinianas.Research in the laboratory is funded by grants-in-aid from the Spanish Ministerio de Educación y Ciencia (SAF2007-66175-C02-01 to EJdlR, BFU2007-61055/BMC to FdP, and BFU2006-00508 to PB).Peer reviewe
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