La FP ha de dur a la universitat? La formació professional compleix uns objectius diferents al batxillerat.

Alumnes de formació professional copen els graus dedicats a formar el professorat. La irrupcio d'estudiants de FP deixa fora de la universitat alguns batxillers.

L'estímul del talent per progressar. El programa Noustalents.cat s'ha de convertir en un planter de joves científics

Divendres passat, el president Montilla, amb els consellers Maragall i Huget, va presentar el programa Noustalents.cat, un projecte gestionar per Talència -Institució per Foment de la Recerca Catalana i la Viència- que té per objectiu la promoció del talent en ciències naturals i socials, tecnologia i matemàtiques.

Optimized back-focal-plane interferometry directly measures forces of optically trapped particles

Back-focal-plane interferometry is used to measure displacements of optically trapped samples with very high spatial and temporal resolution. However, the technique is closely related to a method that measures the rate of change in light momentum. It has long been known that displacements of the interference pattern at the back focal plane may be used to track the optical force directly, provided that a considerable fraction of the light is effectively monitored. Nonetheless, the practical application of this idea has been limited to counter-propagating, low-aperture beams where the accurate momentum measurements are possible. Here, we experimentally show that the connection can be extended to single-beam optical traps. In particular, we show that, in a gradient trap, the calibration product κ·β (where κ is the trap stiffness and 1/β is the position sensitivity) corresponds to the factor that converts detector signals into momentum changes; this factor is uniquely determined by three construction features of the detection instrument and does not depend, therefore, on the specific conditions of the experiment. Then, we find that force measurements obtained from back-focal-plane displacements are in practice not restricted to a linear relationship with position and hence they can be extended outside that regime. Finally, and more importantly, we show that these properties are still recognizable even when the system is not fully optimized for light collection. These results should enable a more general use of back-focal-plane interferometry whenever the ultimate goal is the measurement of the forces exerted by an optical trap.

Optimized back-focal-plane interferometry directly measures forces of optically trapped particles

Back-focal-plane interferometry is used to measure displacements of optically trapped samples with very high spatial and temporal resolution. However, the technique is closely related to a method that measures the rate of change in light momentum. It has long been known that displacements of the interference pattern at the back focal plane may be used to track the optical force directly, provided that a considerable fraction of the light is effectively monitored. Nonetheless, the practical application of this idea has been limited to counter-propagating, low-aperture beams where the accurate momentum measurements are possible. Here, we experimentally show that the connection can be extended to single-beam optical traps. In particular, we show that, in a gradient trap, the calibration product κ·β (where κ is the trap stiffness and 1/β is the position sensitivity) corresponds to the factor that converts detector signals into momentum changes; this factor is uniquely determined by three construction features of the detection instrument and does not depend, therefore, on the specific conditions of the experiment. Then, we find that force measurements obtained from back-focal-plane displacements are in practice not restricted to a linear relationship with position and hence they can be extended outside that regime. Finally, and more importantly, we show that these properties are still recognizable even when the system is not fully optimized for light collection. These results should enable a more general use of back-focal-plane interferometry whenever the ultimate goal is the measurement of the forces exerted by an optical trap.

Effects of nutrients and turbulence on the production of transparent exopolymer particles: a mesocosm study

The production of transparent exopolymer particles (TEP) in response to several environmental variables was studied in 2 mesocosm experiments. The first (Expt 1) examined a gradient of 4 nutrient levels; the second (Expt 2) examined different conditions of silicate availability and zooplankton presence. Tanks were separated in 2 series, one subjected to turbulence and the other not influenced by turbulence. In tanks with nutrient addition, TEP were rapidly formed, with net apparent production rates closely linked to chl a growth rates, suggesting that phytoplankton cells were actively exuding TEP precursors. High nutrient availability increased the absolute concentration of TEP; however, the relative quantity of TEP produced was found to be lower, as TEP concentration per unit of phytoplankton biomass was inversely related to the initial nitrate dose. In Expt 1, an increase in TEP volume (3 to 48 µm equivalent spherical diameter) with nutrient dose was observed; in Expt 2, both silicate addition and turbulence enhanced TEP production and favored aggregation to larger TEP (>48 µm). The presence of zooplankton lowered TEP concentration and changed the size distribution of TEP, presumably by grazing on TEP or phytoplankton. For lower nutrient concentrations, the ratio of particulate organic carbon (POC) to particulate organic nitrogen (PON) followed the Redfield ratio. At higher nutrient conditions, when nutrients were exhausted during the post-bloom, a decoupling of carbon and nitrogen dynamics occurred and was correlated to TEP formation, with a large flow of carbon channeled toward the TEP pool in turbulent tanks. TEP accounted for an increase in POC concentration of 50% in high-nutrient and turbulent conditions. The study of TEP dynamics is crucial to understanding the biogeochemical response of the aquatic system to forcing variables such as nutrient availability and turbulence intensity.

Què s'ha fet en el pla d'igualtat de gènere?

Podeu consultar la Setena trobada de professorat de Ciències de la Salut completa a: http://hdl.handle.net/2445/43352

Què s'ha fet en el pla d'igualtat de gènere?

Podeu consultar la Setena trobada de professorat de Ciències de la Salut completa a: http://hdl.handle.net/2445/43352

Què s'ha fet en el pla d'igualtat de gènere?

Podeu consultar la Setena trobada de professorat de Ciències de la Salut completa a: http://hdl.handle.net/2445/43352

Hi ha diferències en l’èxit acadèmic d’homes i dones en el Curs de formació bàsica?

Objectiu de l'anàlisi és veure la relació entre el nivell d’estudis previ dels aspirants i l’èxit acadèmic al CFB Com mesurem l’èxit acadèmic? Variable 1:Excel·lència (grup d’aspirants que treuen una nota igual o superior a 8) Com mesurem el nivell d’estudis previ? Variable 2:Nivell d’estudis previ (estudis bàsics obligatoris – estudis mitjans 1 – estudis mitjans 2 - estudis superiors) Per què utilitzem la variable nivell d’estudis previ? És la variable que més pes explicatiu té (predicció) en la nota final que l’aspirant obté en el CFB (més que altres variables com classe social, edat, suport familiar...)

Magnetization reversal mechanisms in colloidal dispersions of magnetite particles

We have studied the structural and magnetic properties of colloids consisting of different concentrations of magnetite particles dispersed in kerosene. Our data for the temperature dependence of the low field magnetization and the saturation coercive force of the samples evidenced the occurrence, in different temperature ranges, of Neel- and Brown-type relaxation processes whose characteristics were largely influenced by strong dipolar interparticle interactions.

Lovemarks. Las claves por las que Apple se ha convertido en la marca que más pasiones levanta

En aquest treball es posa en context l'evolució de les marques i els consumidors, la seva relació a través del branding i el branding emocional. Els dos aspectes més importants són l'anàlisi del concepte de Lovemark i de la marca Apple. El treball queda recolzat amb l'elaboració d'una enquesta per confirmar la hipòtesi: "La passió per Apple va més enllà dels productes que llancin".

Projecte de plantació de 23,58 ha de fruiters de llavor al terme municipal de El Poal (Lleida)

Projecte de plantació de 23,58 ha de fruiters de llavor i la seva explotació, construcció d’una bassa de reg per a l’autoabastiment, instal•lació de reg localitzat i construcció d’una nau magatzem per a maquinària, oficina, serveis per als treballadors, magatzem de productes i capçal de reg.

Proyecto de una explotación frutal de 21 ha en Albelda (Huesca)

Transformació d´ una explotació mitjançant la plantació de fruiters, la instal•lació d´una infraestructura de reg i la construcció de una nau-magatzem. A l´ actualitat, la finca es dedica al cultiu de extensius. Es situa a la partida de les Unilles, que pertany al terme municipal d´ Albelda (Osca). La finca ocupa una superfície total de 21 ha, de les quals 8,6 ha es dedicaran a la implantació de perer y 10,3 ha a la de poma, a la resta de la superfície s´ hi faran els camins de la finca i la nau magatzem.

A semi-grand canonical Monte Carlo simulation model for ion binding to ionizable surfaces: Proton binding of carboxylated latex particles as a case study

In this paper, we present a computer simulation study of the ion binding process at an ionizable surface using a semi-grand canonical Monte Carlo method that models the surface as a discrete distribution of charged and neutral functional groups in equilibrium with explicit ions modelled in the context of the primitive model. The parameters of the simulation model were tuned and checked by comparison with experimental titrations of carboxylated latex particles in the presence of different ionic strengths of monovalent ions. The titration of these particles was analysed by calculating the degree of dissociation of the latex functional groups vs. pH curves at different background salt concentrations. As the charge of the titrated surface changes during the simulation, a procedure to keep the electroneutrality of the system is required. Here, two approaches are used with the choice depending on the ion selected to maintain electroneutrality: counterion or coion procedures. We compare and discuss the difference between the procedures. The simulations also provided a microscopic description of the electrostatic double layer (EDL) structure as a function of pH and ionic strength. The results allow us to quantify the effect of the size of the background salt ions and of the surface functional groups on the degree of dissociation. The non-homogeneous structure of the EDL was revealed by plotting the counterion density profiles around charged and neutral surface functional groups. © 2011 American Institute of Physics.