22 research outputs found
Comparing observed and modelled components of the Atlantic Meridional Overturning Circulation at 26° N
The Coupled Model Intercomparison Project (CMIP) allows the assessment of the representation of the Atlantic Meridional Overturning Circulation (AMOC) in climate models. While CMIP Phase 6 models display a large spread in AMOC strength, the multi-model mean strength agrees reasonably well with observed estimates from RAPID1, but this does not hold for the AMOC's various components. In CMIP Phase 6 (CMIP6), the present-day AMOC is characterized by a lack of lower North Atlantic Deep Water (lNADW) due to the small scale of Greenland–Iceland–Scotland Ridge overflow and too much mixing. This is compensated for by increased recirculation in the subtropical gyre and more Antarctic Bottom Water (AABW). Deep-water circulation is dominated by a distinct deep western boundary current (DWBC) with minor interior recirculation compared with observations. The future decline in the AMOC of 7 Sv by 2100 under a Shared Socioeconomic Pathway 5-8.5 (SSP5-8.5) emission scenario is associated with decreased northward western boundary current transport in combination with reduced southward flow of upper North Atlantic Deep Water (uNADW). In CMIP6, wind stress curl decreases with time by 14 % so that wind-driven thermocline recirculation in the subtropical gyre is reduced by 4 Sv (17 %) by 2100. The reduction in western boundary current transport of 11 Sv is more than the decrease in wind-driven gyre transport, indicating a decrease over time in the component of the Gulf Stream originating from the South Atlantic
Acclimation of plants to light gradients in leaf canopies: evidence for a possible role for cytokinins transported in the transpiration stream
English revision
Utiliza imaginativas situaciones de la vida real para ayudar a los estudiantes de doce y trece años a comprender y recordar lo esencial de la etapa clave 3 (Key Stage 3) de Inglés. Este planteamiento refleja el actual cambio en el método de enseñanza que hace énfasis en un aprendizaje contextualizado, es decir, el aprendizaje acerca de las cosas dentro de una situación relevante. Entreteje personajes humorísticos, escenarios de la vida real, rompecabezas y actividades con ejercicios de aprendizaje más formal. Cada tres actividades hay un test de conocimientos. Tiene glosario, respuestas a los pasatiempos y a los tests de conocimientos.SCBiblioteca de Educación del Ministerio de Educación, Cultura y Deporte; Calle San Agustín, 5 - 3 planta; 28014 Madrid; Tel. +34917748000; [email protected]
Comparing observed and modelled components of the Atlantic Meridional Overturning Circulation at 26°N
The Coupled Model Intercomparison Project (CMIP) allows assessment of the representation of the Atlantic Meridional Overturning Circulation (AMOC) in climate models. While CMIP Phase 6 models display a large spread in AMOC strength by a factor of three, the multi-model mean strength agrees reasonably well with observed estimates from RAPID1, but this does not hold for its various components. In CMIP6 the present-day AMOC is characterised by a lack of lower North Atlantic Deep Water (lNADW), due to the small-scale of Greenland-Iceland-Scotland Ridge overflow and too much mixing. This is compensated by increased recirculation in the subtropical gyre and more Antarctic Bottom Water (AABW). Deep-water circulation is dominated by a distinct deep western boundary current (DWBC) with minor interior recirculation compared to observations. The future decline in the AMOC to 2100 of 7Sv under a SSP5-8.5 scenario is associated with decreased northward western boundary current transport in combination with reduced southward flow of upper North Atlantic Deep Water (uNADW). In CMIP6, wind stress curl decreases with time by 14% so that the wind-driven thermocline recirculation in the subtropical gyre is reduced by 4 Sv (17%) by 2100. The reduction in western boundary current transport of 11Sv is more than the decrease in the wind-driven gyre transport suggesting a decrease over time in the component of the Gulf Stream originating in the South Atlantic
The image, status, and reputation of library and information science
La imatge que els bibliotecaris i documentalistes tenen d'ells mateixosés pobra i menysvalorada. L'estudi es basa en una enquesta d'opinió feta a professionals de tot el món. S'hi fa palès l'estatus baix de la professió i s'identifiquen els aspectes que més incideixen en aquesta situació, així com les vies de solució.The image that librarians and documentalists hold of themselves is extremely poor according to an opinion survey given to professionals around the world. While the study reveals the evidently low status of the profession, the factors that occur most frequently in that situation are identified along with ways to remedy the problem
Functional Significance of Shade-Induced Leaf Senescence in Dense Canopies: An Experimental Test Using Transgenic Tobacco
Delayed senescence in cauliflower transformed with an autoregulated isopentenyl transferase gene
Effect of Climate Conditions and Plant Developmental Stage on the Stability of Antibodies Expressed in Transgenic Tobacco
Plants are regarded as a promising system for the production of heterologous proteins. However, little is known about the influence of plant physiology and plant development on the yield and quality of the heterologous proteins produced in plants. To investigate this, tobacco (Nicotiana tabacum cv Samsun NN) was transformed with a single construct that contained behind constitutive promotors the light- and heavy-chain genes of a mouse antibody. The in planta stability of the antibody was analyzed in transgenic plants that were grown under high and low irradiation at 15°C and 25°C. High-light conditions favored the production of biomass, of total soluble protein, and of antibody. The plants grown at 25°C developed faster and contained less antibody per amount of leaf tissue than the plants grown at 15°C. Both endogenous protein and antibody content showed a strong decline during leaf development. The heavy chains of the antibody underwent in planta degradation via relatively stable fragments. In vitro incubations of purified plantibody with leaf extracts of wild-type tobacco indicated the involvement of acidic proteases. It is interesting that the same antibody produced by mouse hybridoma cells exhibited higher stability in this in vitro assay. This may be explained by the assumption that the plant type of N-glycosylation contributes less to the stability of the antibody than the mouse-type of N-glycosylation. The results of this study indicate that proteolytic degradation during plant development can be an important factor affecting yield and homogeneity of heterologous protein produced by transgenic plants