45 resultados para Secret key


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Angiogenesis is a tightly regulated process in vertebrates that leads to the formation of new blood vessels from pre-existing vessels or by the recruitment of bone marrow-derived endothelial precursor cells[1]. During embryogenesis, after stimulation by proangiogenic factors, such as VEGF or FGF, it contributes to the maturation of the vascular plexus. In adults, it is important in some physiologic conditions, such as wound healing or the reproductive cycle in females, although most of the time it is"switched off" by endogenous inhibitors, such as endostatin or angiostatin. Furthermore, its misregulation is the cause of many pathological situations, as it contributes to tumor development[2], diabetic retinopathy[3], rheumatoid arthritis[4], psoriasis[5], but also cardiovascular disorders[6] and obesity[7]

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The fossil crown wasp Electrostephanus petiolatus Brues comb. rev.(Stephanidae, Electrostephaninae) is re-described from a single male preserved in middle Eocene Baltic Amber. The holotype was lost or destroyed around the time of World War II and subsequent interpretations of its identity have been based solely on the brief descriptive comments provided by Brues in his original account. The new specimen matches the original description and illustration provided by Brues in every detail and we hereby consider them to be conspecific, selecting the specimen as a neotype for the purpose of stabilizing the nomenclature for this fossil species. This neotype exhibits a free first metasomal tergum and sternum, contrary to the assertion of previous workers who indicated these to be fused. Accordingly, this species does indeed belong to the genus Electrostephanus Brues rather than to Denaeostephanus Engel & Grimaldi (Stephaninae). Electrostephanus petiolatus is transferred to a new subgenus, Electrostephanodes n. subgen. , based on its elongate pseudo- petiole and slender gaster, but may eventually warrant generic status as the phylogenetic placement of these fossil lineages continues to be clarifi ed. A revised key to the Baltic amber crown wasps is provided.

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Són moltes les veus que, des de la literatura i el pensament, alerten dels perills d"una concepció totalitària de l"espai comú, on l"expressió pública esdevé no pas un dret ciutadà, sinó una exigència comunitària. Si s"exigeix al ciutadà i a l"estranger que ho diguin tot, llavors a les ciutats democràtiques no queda lloc per a la diferència.

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Són moltes les veus que, des de la literatura i el pensament, alerten dels perills d"una concepció totalitària de l"espai comú, on l"expressió pública esdevé no pas un dret ciutadà, sinó una exigència comunitària. Si s"exigeix al ciutadà i a l"estranger que ho diguin tot, llavors a les ciutats democràtiques no queda lloc per a la diferència.

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Previous studies have identified the rivalry among technological platforms as one of the main driving forces of broadband services penetration. This paper draws on data from the Spanish market between 2005 and 2011 to estimate the main determinants of broadband prices. Controlling for broadband tariffs features and network variables, we examine the impact of the different modes of competition on prices. We find that inter-platform competition has no significant effects over prices, while intra-platform competition is a key driver of the prices charged in the broadband market. Our analysis suggests that the impact of different types of competition on prices is critically affected by the levels of development of the broadband market achieved by the considered country

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The vast majority of users don’t seek results beyond the second page offered by the search engine, so if a site fails to be among the top 20 (second page), it says that this page does not have good SEO and, therefore, is not visible to the user. The overall objective of this project is to conduct a study to discover the factors that determine (or not) the positioning of websites in a search engine.

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Gold metallogelators is an emerging area of research. The number of results published in the literature is still scarce. The majority of these gels is observed in organic solvents, and the potential applications are still to be explored. In this work, we present an overview about gold metallogelators divided in two different groups depending on the type of solvent used in the gelation process (organogelators and hydrogelators). A careful analysis of the data shows that aurophilic interactions are a common motif directly involved in gelation involving Au(I) complexes. There are also some Au(III) derivatives able to produce gels but in this case the organic ligands determine the aggregation process. A last section is included about the potential applications that have been reported until now with this new and amazing class of supramolecular assemblies.

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The effects of diet composition and ration size on the activities of key enzymes involved in intermediary metabolism were studied in the liver of gilthead sea bream (Sparus aurata). Highcarbohydrate, low-protein diets stimulated 6-phosphofructo 1-kinase (EC 2.7.1.11), pyruvate kinase (EC 2.7.1.40), glucose-6-phosphate dehydrogenase (EC 1.1.1.49) and 6-phosphogluconate dehydrogenase (EC 1.1.1.44) enzyme activities, while they decreased alanine aminotransferase (EC 2.6.1.2) activity. A high degree of correlation was found between food ration size and the activity of the enzymes 6-phosphofructo 1-kinase, pyruvate kinase, glucose-6-phosphate dehydrogenase (positive correlations) and fructose-1,6-bisphosphatase (EC 3.1.3.11) (negative correlation). These correlations matched well with the high correlation also found between ration size and growth rate in starved fish refed for 22 d. Limited feeding (5 g/kg body weight) for 22 d decreased the activities of the key enzymes for glycolysis and lipogenesis, and alanine aminotransferase activity. The findings presented here indicate a high level of metabolic adaptation to both diet type and ration size. In particular, adaptation of enzyme activities to the consumption of a diet with a high carbohydrate level suggests that a carnivorous fish like Sparus aurata can tolerate partial replacement of protein by carbohydrate in the commercial diets supplied in culture. The relationship between enzyme activities, ration size and fish growth indicates that the enzymes quickly respond to dietary manipulations of cultured fish.

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The effects of diet composition and ration size on the activities of key enzymes involved in intermediary metabolism were studied in the liver of gilthead sea bream (Sparus aurata). Highcarbohydrate, low-protein diets stimulated 6-phosphofructo 1-kinase (EC 2.7.1.11), pyruvate kinase (EC 2.7.1.40), glucose-6-phosphate dehydrogenase (EC 1.1.1.49) and 6-phosphogluconate dehydrogenase (EC 1.1.1.44) enzyme activities, while they decreased alanine aminotransferase (EC 2.6.1.2) activity. A high degree of correlation was found between food ration size and the activity of the enzymes 6-phosphofructo 1-kinase, pyruvate kinase, glucose-6-phosphate dehydrogenase (positive correlations) and fructose-1,6-bisphosphatase (EC 3.1.3.11) (negative correlation). These correlations matched well with the high correlation also found between ration size and growth rate in starved fish refed for 22 d. Limited feeding (5 g/kg body weight) for 22 d decreased the activities of the key enzymes for glycolysis and lipogenesis, and alanine aminotransferase activity. The findings presented here indicate a high level of metabolic adaptation to both diet type and ration size. In particular, adaptation of enzyme activities to the consumption of a diet with a high carbohydrate level suggests that a carnivorous fish like Sparus aurata can tolerate partial replacement of protein by carbohydrate in the commercial diets supplied in culture. The relationship between enzyme activities, ration size and fish growth indicates that the enzymes quickly respond to dietary manipulations of cultured fish.

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The Argentine ant, Linepithema humile, is a world-wide invasive ant species. Its presence has a strong negative impact on ant diversity. The present study attempts to highlight the reasons for the coexistence of this highly dominant species with Plagiolepis pygmaea, the only native ant species that has proved able to resist the invasion in a natural ecosystem in the north-east of the Iberian Peninsula. To quantify the aggressiveness level of both species we performed aggressiveness tests on workers in different areas: a) Argentine ant workers from areas with P. pygmaea, b) Argentine ant workers from areas without P. pygmaea, c) P. pygmaea from a non-invaded area and d) P. pygmaea from an invaded area. We also confronted Argentine ant workers with P. pallidula and T. nigerrimum. These aggressiveness tests showed that the coexistence of these two species of ants was not due to a habituation process, since the aggressiveness level observed between the four kinds of confrontations were fairly similar. We also found a lack of aggressiveness between Argentine ant workers and P. pygmaea, and highly submissive behavior in the latter when confronted with the invader. The peaceful character of P. pygmaea together with its markedly submissive behavior may be the main factors behind the coexistence of these species in the study area

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En la lluita contra el càncer, la recerca de nous fàrmacs cada cop més efectius i específics sovint troba un escull important: en molts tumors hi ha una petita fracció de cèl·lules resistents, que no es poden eliminar fàcilment. Tanmateix, el principal problema no és aquest, sinó que, a més, acostumen a respondre als fàrmacs incrementant la taxa de proliferació i la capacitat de fer metàstasi. Això fa que alguns tractaments no acabin de ser del tot efectius a llarg termini, per la presència cada cop més nombrosa i dispersa d'aquestes cèl·lules canceroses resistents. L'equip de recerca de Joan Massagué, al Memorial Sloan Kettering Cancer Center de Nova York, ha demostrat que aquest efecte a llarg termini induït pels mateixos fàrmacs és perquè les cèl·lules sensibles, abans de morir, preparen un ambient molt favorable per a les resistents.

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We hypothesized that the analysis of mRNA level and activity of key enzymes in amino acid and carbohydrate metabolism in a feeding/fasting/refeeding setting could improve our understanding of how a carnivorous fish, like the European seabass (Dicentrarchus labrax), responds to changes in dietary intake at the hepatic level. To this end cDNA fragments encoding genes for cytosolic and mitochondrial alanine aminotransferase (cALT; mALT), pyruvate kinase (PK), glucose 6-phosphate dehydrogenase (G6PDH) and 6-phosphogluconate dehydrogenase (6PGDH) were cloned and sequenced. Measurement of mRNA levels through quantitative real-time PCR performed in livers of fasted seabass revealed a significant increase in cALT (8.5-fold induction)while promoting a drastic 45-fold down-regulation of PK in relation to the levels found in fed seabass. These observations were corroborated by enzyme activity meaning that during food deprivation an increase in the capacity of pyruvate generation happened via alanine to offset the reduction in pyruvate derived via glycolysis. After a 3-day refeeding period cALT returned to control levels while PK was not able to rebound. No alterations were detected in the expression levels of G6PDH while 6PGDH was revealed to be more sensitive specially to fasting, as confirmed by a significant 5.7-fold decrease in mRNA levels with no recovery after refeeding. Our results indicate that in early stages of refeeding, the liver prioritized the restoration of systemic normoglycemia and replenishment of hepatic glycogen. In a later stage, once regular feeding is re-established, dietary fuel may then be channeled to glycolysis and de novo lipogenesis.

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We hypothesized that the analysis of mRNA level and activity of key enzymes in amino acid and carbohydrate metabolism in a feeding/fasting/refeeding setting could improve our understanding of how a carnivorous fish, like the European seabass (Dicentrarchus labrax), responds to changes in dietary intake at the hepatic level. To this end cDNA fragments encoding genes for cytosolic and mitochondrial alanine aminotransferase (cALT; mALT), pyruvate kinase (PK), glucose 6-phosphate dehydrogenase (G6PDH) and 6-phosphogluconate dehydrogenase (6PGDH) were cloned and sequenced. Measurement of mRNA levels through quantitative real-time PCR performed in livers of fasted seabass revealed a significant increase in cALT (8.5-fold induction)while promoting a drastic 45-fold down-regulation of PK in relation to the levels found in fed seabass. These observations were corroborated by enzyme activity meaning that during food deprivation an increase in the capacity of pyruvate generation happened via alanine to offset the reduction in pyruvate derived via glycolysis. After a 3-day refeeding period cALT returned to control levels while PK was not able to rebound. No alterations were detected in the expression levels of G6PDH while 6PGDH was revealed to be more sensitive specially to fasting, as confirmed by a significant 5.7-fold decrease in mRNA levels with no recovery after refeeding. Our results indicate that in early stages of refeeding, the liver prioritized the restoration of systemic normoglycemia and replenishment of hepatic glycogen. In a later stage, once regular feeding is re-established, dietary fuel may then be channeled to glycolysis and de novo lipogenesis.

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The physical education curriculum stresses the importance of improving students’ key motor skills. This idea agrees with the contributions of research into motor development concerning the important role these skills play in child development. In order to facilitate this improvement is essential to know the different basic aspects of how these key motor skills evolve as well as the essential factors related to the characteristics and conditions of educational practice