Holographic optical tweezers combined with back-focal-plane displacement detection

A major problem with holographic optical tweezers (HOTs) is their incompatibility with laser-based position detection methods, such as back-focal-plane interferometry (BFPI). The alternatives generally used with HOTs, like high-speed video tracking, do not offer the same spatial and temporal bandwidths. This has limited the use of this technique in precise quantitative experiments. In this paper, we present an optical trap design that combines digital holography and back-focal-plane displacement detection. We show that, with a particularly simple setup, it is possible to generate a set of multiple holographic traps and an additional static non-holographic trap with orthogonal polarizations and that they can be, therefore, easily separated for measuring positions and forces with the high positional and temporal resolutions of laser-based detection. We prove that measurements from both polarizations contain less than 1% crosstalk and that traps in our setup are harmonic within the typical range. We further tested the instrument in a DNA stretching experiment and we discuss an interesting property of this configuration: the small drift of the differential signal between traps.

Going with the consumer towards the social Web environment : a review of extant knowledge

The social Web environment cannot be explained without taking into account the use made by consumers of the web technologies in the field of e-commerce. Starting with a systematic background of the growing body of research on marketing and consumer behaviour on the Web; this article presents a critical review of the main contributions on this theme, integrating also the research field of consumer behaviour in the social Web environment. It concludes with some managerial guidelines for successful use of the social Web in the commercial activities and in the establishment of fruitful relationships between the consumers and the brand.

Contemporary engagements within corridors of the past: temporal elasticity, graffiti, and the materiality of St. Rock Street, Barcelona

In a medieval Barcelonan side-street, urine, rubbish, and a bewildering array of graphic imagery splatters the narrowing walls between two major thoroughfares. A contemporary conflict between residents, unknown artists and others is played out using banners, bottles, stickers, posters, stencils, spray paint, and bodily substances. In this shadowed liminality, local and global debates are superimposed upon substructures constructed from disease, prostitution, and the Saint of the Plague. The continuing urban struggle constitutes temporal statements of dirt and purity, violence and humour, dominance and resistance, death and salvation. Like the renovated facades masking the crumbling remains of structures long neglected, the government’s literal whitewashing of the art is a temporal cover-up of a discursive symptom stretching from deeply embedded preconditions. However, from his niche in the angular bend of the alley bearing his name, the statue of St. Rock remains unblinkingly staring, raised above the contestations expressed below.

Creación y gestión de una marca. El caso IUBUD, fundas de madera para dispositivos Apple

Aquest treball d’investigació, té com a objectiu principal, desenvolupar una estratègia de Brand management després d’haver estudiat diferents teories sobre creació i gestió de marques. Des de el naixement de las marques, han sigut molts els autors que han estudiat aquest fenomen per assentar las bases del que avui es coneix com branding, disciplina que s’encarrega de l’estudi d’aquestes. Entre aquests autors podem trobar diferents teories o models de Brand management. El meu treball de final de carrera, en una primera part, analitzarà els conceptes des de la perspectiva dels diferents autors. Són diverses las metodologies que podem trobar en aquesta disciplina, des de el seu origen més acadèmic, de màrqueting o econòmic, per tant, durant el desenvolupament d’aquest treball final de carrera, s’estudiaran algunes d’aquestes vessants i es valoraran las seves conclusions, per a posteriorment desenvolupar una metodologia pròpia i dur la a la pràctica per a la creació d’una marca real. La segona part consisteix en aplicar la metodologia, a un cas pràctic, i poder crear una marca des de cero, amb una base científica, que ens guiï al llarg de tots els processos de presa de decisions. Des de l’anàlisi previ, passant per l’estratègia de marca i finalment de comunicació. Això ens ha permès crear una marca per a un producte concret, i aconseguir posicionar lo en el mercat. Per finalitzar, es presenten las aplicacions corresponents a la marca, resultants d’haver seguit la metodologia plantejada inicialment. Aquest treball de final de carrera es contempla amb annexos en els que queden documentats els processos y anàlisis citats al llarg del desenvolupament.

Quaternary active tectonic structures in the offshore Bajo Segura basin (SE Iberian Peninsula Mediterranean Sea).

The Bajo Segura fault zone (BSFZ) is the northern terminal splay of the Eastern Betic shear zone (EBSZ), a large left-lateral strike-slip fault system of sigmoid geometry stretching more than 450 km from Alicante to Almería. The BSFZ extends from the onshore Bajo Segura basin further into the Mediterranean Sea and shows a moderate instrumental seismic activity characterized by small earthquakes. Nevertheless, the zone was affected by large historical earthquakes of which the largest was the 1829 Torrevieja earthquake (IEMS98 X). The onshore area of the BSFZ is marked by active transpressive structures (faults and folds), whereas the offshore area has been scarcely explored from the tectonic point of view. During the EVENT-SHELF cruise, a total of 10 high-resolution single-channel seismic sparker profiles were obtained along and across the offshore Bajo Segura basin. Analysis of these profiles resulted in (a) the identification of 6 Quaternary seismo-stratigraphic units bounded by five horizons corresponding to regional erosional surfaces related to global sea level lowstands; and (b) the mapping of the active sub-seafloor structures and their correlation with those described onshore. Moreover, the results suggest that the Bajo Segura blind thrust fault or the Torrevieja left-lateral strike-slip fault, with prolongation offshore, could be considered as the source of the 1829 Torrevieja earthquake. These data improve our understanding of present deformation along the BSFZ and provide new insights into the seismic hazard in the area.