Phosphorus dynamics in waters of the Pacific Ocean

Tagged phosphorus was used to measure principal indices of mineral phosphorus variations in the euphotic zone of the East Pacific, i.e. total rate of uptake of phosphate phosphorus by microplankton (A_t), fraction consumed by phytoplankton (A_p/A_t), and turnover time (T). A_t reached its greatest values (150-280 ng/l/hour) in the upwelling zone of the Peru traverse, where development of phytoplankton was induced by upwelling. In other areas of this traverse values were 40-80 ng/l/hour in surface layers. In less productive waters on two other profiles (off Central America and California), values were lower, between 20 and 40 ng/l. On the vertical profile maxima of A_t were found at the upper boundary of the thermocline. Turnover time of PO4 phosphorus (T) in zones of phytoplankton abundance was very short, between 1.5 and 4 days. At most other stations it was 10-40 days, increasing to 100-200 days or longer at the lower boundary of the euphotic zone. In areas of phytoplankton abundance it accounted for 60-80% of total uptake of PO4 phosphorus. But in zones of elevated bacterial abundance, A_p/A_t fell to 20-40%. Data indicating lack of correlation between PO4 phosphorus and productivity are presented. It is emphasized that the above measures of PO4 phosphorus dynamics can be used for obtaining measures of functional condition and successional phase of marine plankton communities.

Curso de literatura general.

Indices.

Alfonsi Salmeronis ... Commentarii in Euangelicam historiam [et] in Acta Apostolorum in duodecim tomos distributi ...

Mode of access: Internet.

Release currents of IP₃ receptor channel clusters and concentration profiles

We simulate currents and concentration profiles generated by Ca2+ release from the endoplasmic reticulum (ER) to the cytosol through IP3 receptor channel clusters. Clusters are described as conducting pores in the lumenal membrane with a diameter from 6 nm to 36 nm. The endoplasmic reticulum is modeled as a disc with a radius of 1–12 mm and an inner height of 28 nm. We adapt the dependence of the currents on the trans Ca2+ concentration (intralumenal) measured in lipid bilayer experiments to the cellular geometry. Simulated currents are compared with signal mass measurements in Xenopus oocytes. We find that release currents depend linearly on the concentration of free Ca2+ in the lumen. The release current is approximately proportional to the square root of the number of open channels in a cluster. Cytosolic concentrations at the location of the cluster range from 25 μM to 170 μM. Concentration increase due to puffs in a distance of a few micrometers from the puff site is found to be in the nanomolar range. Release currents decay biexponentially with timescales of < 1 s and a few seconds. Concentration profiles decay with timescales of 0.125–0.250 s upon termination of release.

Notas sobre un modelo político-administrativo eficaz para el siglo XX. Dirección integral del desarrollo: el caso de Costa Rica

Introducción Debemos dejar claro, desde el principio, la premisa ideológica-política que sustenta todo el análisis presente: el Estado y su Administración no tienen que ser “inherentemente” perniciosos ni ineficaces o ineficientes en su papel interventor y regulador del sistema social como un todo. Son los hombres y los esquemas que éstos desarrollan, quienes generan condiciones de mediatización y ausencia del compromiso y motivación en la burocracia como sistema de acción del Estado y en los cuadros tecnocráticos estatales, Pero no tiene que ser siempre así, y menos de frente a un Estado que en futuro previsible no va a perder su papel, significación e impacto global y específico en América Latina, a pesar de los embates por privatizar y reducir el gasto público.

Objetivo fundamental de la universidad sostenible; educar al eco-ciudadano

Resumen No se puede hablar de desarrollo sostenible, si por desarrollo se entiende el modelo actualmente imperante en la sociedad de consumo del siglo  XXI. Para que sea sostenible se necesita situar esta sostenibilidad en un modelo ecológico de desarrollo humano. ¿En qué consiste este último tipo de desarrollo?¿En qué cosmovisión se soporta? Es la primera pregunta que se pretende contestar en el presente artículo. Para ello nos fijamos en siete puntos: quiénes son los autores que han contribuido al nacimiento del nuevo pensamiento; por qué es necesaria otra metanarrativa; qué cosmovisiones se han sucedido en la historia; cuál es la finalidad de la cosmovisión ecológica y de la moderna; principios fundamentales de ambas cosmologías; cuáles son las raíces físicas y astrofísicas de la cosmovisión ecológica y de la mecanicista o clásica; y qué consecuencias filosóficas se derivan de esos referentes.

A experiência da ESEV TV - televisão académica on-line

The study focuses on the analysis of the academic experience entitled Television of the Superior School of Education from Viseu (ESEV TV). This academic project has been an online experience since 2011 and comprises a space of experimentation and broadcasting for audiovisual contents. The significance of the digital sphere embodied mostly through the internet places this medium as the ideal platform to the exchange of contents created by the academic community and favors its dissemination to a heterogeneous audience. The implementation of this audiovisual project encourages the collaboration and the creative initiative of those involved in it and, at the same time, intents to improve the capabilities of expression and communication skills of the participants. It is also an objective of this creative initiative to build an historical archive of audiovisual produced material as also as to promote the integration of students, strengthening ethical and moral values and increasing communication strategies. ESEV TV is available to all study cycles from the institution where it is allocated and represents a workshop camp where it is possible to practice techniques and develop knowledge in the television production area. The accomplishment of the project purpose is inextricably dependent on the existence of a working group constantly updated, also multidisciplinary, that aggregates students from different areas. This complex interdependent mission is guided by teachers with knowledge and experience in the audiovisual field. The team work expects to produce an interesting online schedule that reunites, at the same time, information, culture, education and entertainment.

Resolución 186 del 30 de septiembre de 2009: ¿Bajo que criterios evalúa la cámara de comercio la toma de decisiones en las sociedades de responsabilidad limitada ?

Servicios registrales