60 resultados para Filósofos - Portugal - séc. 20


Relevância:

20.00% 20.00%

Publicador:

Resumo:

Samples of YBa2Cu3O7-y + 20 mol% Y2BaCuO5 have been melt processed and quenched from temperatures ranging from 975 to 1100°C. The microstructure of the samples have been characterized via a combination of x-ray diffractometry, optical microscopy, scanning electron microscopy, energy dispersive x-ray spectrometry and wavelength dispersive x-ray spectrometry. BaCuO2 (BC1) and BaCu2O2 (BC2) crystallize from the melt of samples quenched from temperatures between 985 and 1100°C in air. The average yttrium content differs for BC1 and BC2, and it is 4.3 and 5.1 at.%, respectively. Holding times of 20 hours at temperatures above or equal to 1040°C give rise to a dendritic pattern of BC1 surrounded by BC2. The complex changes of the nature of the melt as a function of temperature and time are likely to play a significant role in the mechanism of melt texturing.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Background IL-20 is a pleiotrophic member of the IL-10 family and plays a role in skin biology and the development of haematopoietic cells. Recently, IL-20 has been demonstrated to have potential anti-angiogenic effects in non-small cell lung cancer (NSCLC) by down regulating COX-2. Methods The expression of IL-20 and its cognate receptors (IL-20RA/B and IL-22R1) was examined in a series of resected fresh frozen NSCLC tumours. Additionally, the expression and epigenetic regulation of this family was examined in normal bronchial epithelial and NSCLC cell lines. Furthermore, the effect of IL-20 on VEGF family members was examined. Results The expression of IL-20 and its receptors are frequently dysregulated in NSCLC. IL-20RB mRNA was significantly elevated in NSCLC tumours (p < 0.01). Protein levels of the receptors, IL-20RB and IL-22R1, were significantly increased (p < 0.01) in the tumours of NSCLC patients. IL-20 and its receptors were found to be epigenetically regulated through histone post-translational modifications and DNA CpG residue methylation. In addition, treatment with recombinant IL-20 resulted in decreased expression of the VEGF family members at the mRNA level. Conclusions This family of genes are dysregulated in NSCLC and are subject to epigenetic regulation. Whilst the anti-angiogenic properties of IL-20 require further clarification, targeting this family via epigenetic means may be a viable therapeutic option in lung cancer treatment. © 2011 Elsevier Ltd. All rights reserved.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This is the first volume in a book series examining how organizations in the creative industries respond to disruptive change and how they themselves generate business innovations. The aspiration of this book series is to understand some of the common forces behind the disruptions occurring in so many creative industries today and identifying the most promising strategies and responses by organizations to create new value propositions, business models and business practices that can enable these industry participants to cope with and eventually thrive as their industries and sectors are transformed. The chapters included in the volume examine the processes of disruption and transformation due to the technology of the Internet, social forces driven by social media, the development of new portable digital devices with greater capabilities and smaller size, the decreasing costs of new information, and the creation of new business models and forms of intellectual property ownership rights for a digitized industry. The context for this volume is the publishing industries, understood as the industries for the publishing of fiction and non-fiction books, academic literature, consumer as well as trade magazines, and daily newspapers. This volume includes chapters by an internationally diverse array of media scholars whose chapters provide insights into these phenomena in Eastern Europe, Finland, France, Germany, Norway, Portugal, Russia, and the United States, using different methodological frameworks including, but not limited to, surveys, in-depth interviews and multiple-case studies. One gap that this book series seeks to fill is that between the study of business innovation and disruption by innovation scholars largely based in business school settings and similar studies by scholarly experts from non-business school disciplines, including the broader social sciences (e.g. sociology, political science, economic geography) and creative industry based professional school disciplines (e.g. architecture, communications, design, film making, journalism, media studies, performing arts, photography and television). Future volumes of this book series will examine disruption and business innovation in the film, video and photography sectors (volume two), the music sector (volume three) and interactive entertainment (volume four), with subsequent volumes focusing on the most relevant developments in creative industry business innovation and disruption that emerge.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This article summarizes a panel held at the 15th Pacific Asia Conference on Information Systems (PACIS) in Brisbane, Austrailia, in 2011. The panelists proposed a new research agenda for information systems success research. The DeLone and McLean IS Success Model has been one of the most influential models in Information Systems research. However, the nature of information systems continues to change. Information systems are increasingly implemented across layers of infrastructure and application architecture. The diffusion of information systems into many spheres of life means that information systems success needs to be considered in multiple contexts. Services play a much more prominent role in the economies of countries, making the “service” context of information systems increasingly important. Further, improved understandings of theory and measurement offer new opportunities for novel approaches and new research questions about information systems success.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The peritubular zone of the rat testis has an extensive extracellular matrix (ECM). Fibronectin (FN) is distributed primarily in the basal lamina of the seminiferous tubule boundary tissue and is synthesized by peritubular myoid cells. Several extracellular changes are mediated by growth factors and these changes occur at the time of hormone mediated testicular development, particularly in the peritubular zone. The effects of serum or dibutyryl cyclic AMP (cAMP) on FN production by the mesenchymal peritubular myoid cells were evaluated. Rats of various ages (10, 15, 20, 40 and 80 days) were employed for immunofluorescent localization of rat testicular FN in frozen sections. In all age groups tested, FN was primarily present in a broad layer around each seminiferous tubule, and blood vessel, and in variable distribution throughout the interstitial stroma. By day 20 there was no clear distinction in FN staining between the peritubular zone and the interstitial tissue. This indicates an involvement of FN in the ECM developments which occur in the peritubular zone of the testis at this time. The peritubular myoid cells were isolated from 20-22 day old rat testis and cultured on glass coverslips. These cells were grown to confluence with 10% fetal calf serum (FCS) in medium until day 4 and then subcultured to have secondary monocultures maintained with or without serum. By means of immunofluorescence and cytochemistry using avidin-biotin peroxidase complex it was observed that peritubular myoid cells were positive for FN and most of the FN was localized in the perinuclear region. Subcultured peritubular myoid cells maintained for 4 days in medium containing FCS developed an extensive interconnecting FN matrix. In the presence of 0.5 mM cAMP in culture, FN became localized along the filamentous process of peritubular myoid cells and more prominently in the areas of triangulated multi-cell aggregates as well as on the surface of the contracted small spherical cells. The addition of cAMP in the presence of FCS, also caused a noticeable change in the staining pattern; FN was detected along the filamentous process developing into a complex network of cells encased in an extensive matrix. It would appear that the translocation of FN in the cytoplasmic extensions of peritubular myoid cells may be a direct consequence of morphological changes associated with metabolic regulation of cAMP. This may also be related to the puberty associated development of in vivo changes in the ECM produced by peritubular myoid cells.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Using a state, pressure, response framework, we provide an evidence-based reflection on environmental outcomes in Australia and New Zealand across the domains of climate change, biodiversity, freshwater and marine management, emphasising the role of Indigenous and business perspectives. Significant developments have occurred in the past 20 years through affirmation of Indigenous rights and responsibilities. Responses to climate change have tended to emphasise passive risk management with unclear outcomes. Despite meeting biodiversity protection targets, outcomes are worsening, suggesting a need to challenge the dualistic preservation/production land categorisations. In freshwater and marine management, a mix of collaborative and market-based responses has emerged, although their efficacy remains untested. A reliance on voluntary approaches by business makes critical assessment of progress difficult. Thus, despite strong progress in some areas, the adaptiveness of environmental management remains limited, and many indicators suggest continuing decline in environmental condition. Our responses have been largely pacifying in nature, leading to perverse outcomes and failure to acknowledge alternatives that might address deteriorating environmental conditions. A shift is needed towards deliberative policy experimentation that truly values the application of novel and diversified approaches and facilitates integrated learning across environmental domains.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The 20% ethanol intermittent-access (IAE) two-bottle-choice drinking procedure has been shown to produce high voluntary ethanol consumption in a number of rat strains. For this study, we applied this procedure to male Fischer (F344) rats, a strain previously reported to exhibit low levels of ethanol consumption. We also subjected these animals to a two-week ethanoldeprivation- period to see if they would exhibit an alcohol deprivation effect (ADE) signified by a transient increase in alcohol consumption following deprivation. Our data show a separation between high and low consuming animals within this strain, with high-consumers exhibiting an escalation in consumption. In contrast, Fischer rats did not show a significant separation between high and low consumers or any significant escalation in consumption, using the 20% ethanol continuous-access two-bottle-choice drinking protocol. Following the two-week deprivation period, animals in the high (but not the low) IAE group exhibited the transient increase in ethanol consumption and preference typically associated with an ADE. Together, the data suggest that the intermittent access protocol is a useful protocol for increasing ethanol consumption.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Bactrocera papayae Drew & Hancock, Bactrocera philippinensis Drew & Hancock, Bactrocera carambolae Drew & Hancock, and Bactrocera invadens Drew, Tsuruta & White are four horticultural pest tephritid fruit fly species that are highly similar, morphologically and genetically, to the destructive pest, the Oriental fruit fly, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae). This similarity has rendered the discovery of reliable diagnostic characters problematic, which, in view of the economic importance of these taxa and the international trade implications, has resulted in ongoing difficulties for many areas of plant protection and food security. Consequently, a major international collaborative and integrated multidisciplinary research effort was initiated in 2009 to build upon existing literature with the specific aim of resolving biological species limits among B. papayae, B. philippinensis, B. carambolae, B. invadens and B. dorsalis to overcome constraints to pest management and international trade. Bactrocera philippinensis has recently been synonymized with B. papayae as a result of this initiative and this review corroborates that finding; however, the other names remain in use. While consistent characters have been found to reliably distinguish B. carambolae from B. dorsalis, B. invadens and B. papayae, no such characters have been found to differentiate the latter three putative species. We conclude that B. carambolae is a valid species and that the remaining taxa, B. dorsalis, B. invadens and B. papayae, represent the same species. Thus, we consider B. dorsalis (Hendel) as the senior synonym of B. papayae Drew and Hancock syn.n. and B. invadens Drew, Tsuruta & White syn.n. A redescription of B. dorsalis is provided. Given the agricultural importance of B. dorsalis, this taxonomic decision will have significant global plant biosecurity implications, affecting pest management, quarantine, international trade, postharvest treatment and basic research. Throughout the paper, we emphasize the value of independent and multidisciplinary tools in delimiting species, particularly in complicated cases involving morphologically cryptic taxa.