22 resultados para Change in values
Resumo:
The issue of how contractility and adhesion are related to cell shape and migration pattern remains largely unresolved. In this paper we report that Gleevec (Imatinib), an Abl family kinase inhibitor, produces a profound change in the shape and migration of rat bladder tumor cells (NBTII) plated on collagen-coated substrates. Cells treated with Gleevec adopt a highly spread D-shape and migrate more rapidly with greater persistence. Accompanying this more spread state is an increase in integrin-mediated adhesion coupled with increases in the size and number of discrete adhesions. In addition, both total internal reflection fluorescence microscopy (TIRFM) and interference reflection microscopy (IRM) revealed a band of small punctate adhesions with rapid turnover near the cell leading margin. These changes led to an increase in global cell-substrate adhesion strength, as assessed by laminar flow experiments. Gleevec-treated cells have greater RhoA activity which, via myosin activation, led to an increase in the magnitude of total traction force applied to the substrate. These chemical and physical alterations upon Gleevec treatment produce the dramatic change in morphology and migration that is observed.
Resumo:
Freshwater species worldwide are experiencing dramatic declines partly attributable to ongoing climate change. It is expected that the future effects of climate change could be particularly severe in mediterranean climate (med-) regions, which host many endemic species already under great stress from the high level of human development. In this article, we review the climate and climate-induced changes in streams of med-regions and the responses of stream biota, focusing on both observed and anticipated ecological responses. We also discuss current knowledge gaps and conservation challenges. Expected climate alterations have already been observed in the last decades, and include: increased annual average air temperatures; decreased annual average precipitation; hydrologic alterations; and an increase in frequency, intensity and duration of extreme events, such as floods, droughts and fires. Recent observations, which are concordant with forecasts built, show stream biota of med-regions when facing climate changes tend to be displaced towards higher elevations and upper latitudes, communities tend to change their composition and homogenize, while some life-history traits seem to provide biota with resilience and resistance to adapt to the new conditions (as being short-lived, small, and resistant to low streamflow and desiccation). Nevertheless, such responses may be insufficient to cope with current and future environmental changes. Accurate forecasts of biotic changes and possible adaptations are difficult to obtain in med-regions mainly because of the difficulty of distinguishing disturbances due to natural variability from the effects of climate change, particularly regarding hydrology. Long-term studies are needed to disentangle such variability and improve knowledge regarding the ecological responses and the detection of early warning signals to climate change. Investments should focus on taxa beyond fish and macroinvertebrates, and in covering the less studied regions of Chile and South Africa. Scientists, policy makers and water managers must be involved in the climate change dialogue because the freshwater conservation concerns are huge.
Resumo:
Sex change in the protandrous fish Amphiprion akallopisos Bleeker, 1853 (F.Pomacentridae) has been analysed. Experiments consisted of placing males together after being separated from their mates, and observe changes in gonad histology at different periods, in order to identify signs of the sex change process. The presence of a first invagination on the male gonad wall, and the observation of the first cortical alveoli oocytes as an indication of the beginning of the vitellogenesis process, was the first symptom of the sex change, which has been detected after 18 days in one of the males. Period needed for the sex changing process was size independent. The process by which wall invagination is converted into ovarian lumen in the future mature ovary is also described
Resumo:
This article looks at the musical activity carried out at Palafrugell Music School as a musical education centre over the past forty years. After giving a brief description of the work carried out there by vocal and instrumental groups, the article analyses and offers examples and tangible motives that use activities to show that forming part of a coral or instrumental group helps personal development and promotes the acquisition of habits, alongside musical training and learning. In short, an education in values
Resumo:
El turisme rural, l’esport i la salut han adquirit de forma progressiva en els últims anys una importància cada vegada més gran. Una part creixent de la població ha anat incorporant de mica en mica dies de descans i repòs durant tot l’any. Aquesta realitat és deguda, parcialment, a l’augment del temps lliure i a la consideració del seu gaudi com un element per a la millora de la qualitat de vida. El turisme rural, a causa del canvi de valors experimentat en la societat contemporània, s’interrelaciona amb altres productes, com ara el turisme termal i les activitats esportives realitzades en contacte amb la natura, igual que amb altres serveis del sector del lleure, com ara l’espectacle, el joc, la cultura, etc. Aquesta situació determina la necessitat de plantejar sistemes de gestió professionals i aplicar estratègies que permetin de generar factors competitius i diferenciadors. Les empreses turístiques que han adoptat el paradigma empresarial de la gestió de qualitat total es caracteritzen per oferir qualitat de servei, i per assolir aquesta qualitat cal disposar d’un equip d’especialistes altament qualificats i experimentats. El propòsit d’aquest treball és analitzar les titulacions oficials relacionades amb les estacions termals en zones rurals i els serveis associats.
Resumo:
El turismo rural, el deporte y la salud han venido adquiriendo de forma progresiva en los últimos años una importancia cada vez mayor. Una parte creciente de la población ha ido incorporando paulatinamente días de descanso y reposo durante todo el año. Esta realidad es debida, en parte, al aumento del tiempo libre y a la consideración de su disfrute como un elemento para la mejora de la calidad de vida. El turismo rural, debido al cambio de valores sufrido en la sociedad contemporánea, se interrelaciona con otros productos como el turismo termal y las actividades deportivas realizadas en contacto con la naturaleza, al igual que con otros servicios del sector ocio, como pueden ser el espectáculo, el juego, la cultura, etc. Esta situación determina la necesidad de plantear sistemas de gestión profesionales y aplicar estrategias que permitan generar factores competitivos y diferenciadores. Las empresas turísticas que han adoptado el paradigma empresarial de la gestión de calidad total se caracterizan por ofrecer calidad de servicio, y para alcanzar dicha calidad es necesario disponer de un equipo de especialistas altamente cualificados y experimentados. El propósito de este trabajo es analizar las titulaciones oficiales relacionadas con las estaciones termales en zonas rurales y los servicios asociados.
Resumo:
Nitrogen isotope composition (δ15N) in plant organic matter is currently used as a natural tracer of nitrogen acquisition efficiency. However, the δ15N value of whole leaf material does not properly reflect the way in which N is assimilated because isotope fractionations along metabolic reactions may cause substantial differences among leaf compounds. In other words, any change in metabolic composition or allocation pattern may cause undesirable variability in leaf δ15N. Here, we investigated the δ15N in different leaf fractions and individual metabolites from rapeseed (Brassica napus) leaves. We show that there were substantial differences in δ15N between nitrogenous compounds (up to 30 ) and the content in (15N enriched) nitrate had a clear influence on leaf δ15N. Using a simple steady-state model of day metabolism, we suggest that the δ15N value in major amino acids was mostly explained by isotope fractionation associated with isotope effects on enzyme-catalysed reactions in primary nitrogen metabolism. δ15N values were further influenced by light versus dark conditions and the probable occurrence of alternative biosynthetic pathways. We conclude that both biochemical pathways (that fractionate between isotopes) and nitrogen sources (used for amino acid production) should be considered when interpreting the δ15N value of leaf nitrogenous compounds