Deterministic ratchet from stationary light fields

Ratchets are dynamic systems where particle transport is induced by zero-average forces due to the interplay between nonlinearity and asymmetry. Generally, they rely on the effect of a strong external driving. We show that stationary optical lattices can be designed to generate particle flow in one direction while requiring neither noise nor driving. Such optical fields must be arranged to yield a combination of conservative (dipole) and nonconservative (radiation pressure) forces. Under strong friction all paths converge to a discrete set of limit periodic trajectories flowing in the same direction.Comment: 6 pages, 4 figure

Too little intervention or too much? The contribution of the State to the development of wine cooperatives in Spain

This article analyses the contribution of the State to the expansion of wine cooperatives in Spain over the course of the twentieth and the early years of the twenty-first centuries. We examine the legislation that created the institutional framework for their development, and the role of the State in providing both financial and technical assistance. We show that the State's contribution was critical to differences not just in the rate of their expansion but also in their distribution throughout the main winegrowing regions of Spain. Finally, we assess the consequences of State intervention on their overall performance, highlighting a lack of involvement as the main reason for the slow development of wine cooperatives in the early period, but also the dangers of excessive State intervention later

Giant enhanced diffusion of gold nanoparticles in optical vortex fields

We study the diffusion of a metal nanoparticle in the nonconservative force field of an optical vortex lattice. Radiation pressure in the vortex array is shown to induce a giant enhancement over the free thermal diffusion. Langevin dynamics simulations show that the diffusion coefficient of (50 nm radius) gold particles at room temperature is enhanced by 2 orders of magnitude at power densities of the order or smaller than those used to trap nanoparticles with optical tweezers

Scattering forces from the curl of the spin angular momentum of a light field

Light forces on small (Rayleigh) particles are usually described as the sum of two terms: the dipolar or gradient force and the scattering or radiation pressure force. The scattering force is traditionally considered proportional to the Poynting vector, which gives the direction and magnitude of the momentum flow. However, as we will show, there is an additional nonconservative contribution to the scattering force arising in a light field with nonuniform helicity. This force is shown to be proportional to the curl of the spin angular momentum of the light field. The relevance of the spin force is illustrated in the simple case of a 2D field geometry arising in the intersection region of two standing wavesThis work was supported by the Spanish MEC through the Consolider NanoLight (CSD2007-00046), FIS2005-05137 and FIS2006-11170-C02-02 projects, Microseres-CM and by the Spanish-French PICASSO program (HF2007- 0068

Reliability of two measurement indices for gingival enlargement

Background and objective: The objective of this study was to analyze the concordance of the vertical gingival overgrowth index (GOi) and the horizontal Miranda & Brunet index (MBi) and to compare their reliability and reproducibility for an early diagnosis of gingival enlargement. A wide range of methods has been employed to determine the severity of drug-induced gingival enlargement (DIGE) that has resulted in uncertainty with regard to the prevalence of this side effect. In recent studies, different indices have been used to grade DIGE. The large variability observed between studies and the differences between vertical and horizontal gingival-enlargement measurements could be the result of the use of nonreliable indices during the measurement process. Some indices involve invasive procedures that require many measurements, or even a data-processing system, while others are less convenient and technically expensive and complex. In previous studies we used two complementary indices - the vertical GOi and the horizontal MBi. The results of these studies found some differences between both indices, with the MBi rendering higher estimates of DIGE prevalence that was attributed to its greater sensitivity for the detection of minimal changes in gingival thickness. To our knowledge, there are no studies comparing different measurement indices for gingival enlargement that are supported by statistical concordance analysis. Material and methods:   Twelve plaster casts from patients who had worn orthodontic brackets, and who had different degrees of chronic inflammatory gingival enlargement, were analyzed. Three previously trained examiners registered twice the degree of buccal overgrowth, using the GOi and MBi, in all cast models with a minimum interval of 7 d between the first and the second evaluation. In total, from each cast, measurements from 16 gingival sites were taken using the GOi, and from nine gingival units (mesial and distal sites measurements) using the MBi. Concordance analysis of the registered measurements (intra-examiner and among examiners) for each index and between indices was assessed using the nonweighted Kappa index with a confidence interval of 95%. Results: We obtained 648 values for the GOi and the MBi. The overall score 0 (indicating absence of enlargement) was 32.7% and 19.8% for GOi and MBi, respectively, score 1 (light/moderate) was 39.7% and 48.1%, and score 2 (severe) was 27.6% and 32.1%. Concordance analysis for each index showed intra-examiner Kappa values of 0.820 for the GOi and 0.830 for the MBi. Interexaminer Kappa values were 0.720 for the GOi and 0.770 for the MBi. Concordance between indices showed Kappa values for the same examiner of 0.600, whereas concordance among different examiners was 0.550. Discrepancies between indices indicated a systematic skew, with 79-82.1% of discrepancy associated with a higher value for the MBi compared with the GOi. Conclusion: Both gingival enlargement indices analyzed are reliable, complementary and applicable for measuring gingival overgrowth. However, the MBi shows, with fewer measurements, a greater sensitivity than the GOi for the detection of the early stages of gingival enlargement, being adequate for the screening of large populations at risk

Una experiència d'aprenentatge basada en projectes en l'àmbit de la informàtica

En aquest treball es presenta l'adaptació a l'EEES de les assignatures de Algorismes i Programació (AP) i Llenguatges de Programació (LP) de la titulació d'Enginyeria Informàtica de la UAB. Per a aquesta adaptació s'ha utilitzat, entre d'altres, una metodologia d'aprenentatge basada en un projecte comú. AP engloba coneixements teòrics sobre anàlisi i disseny d'algorismes, mentre que a LP es treballa el llenguatge de programació C i la seva aplicació pràctica. Tradicionalment aquestes dues assignatures s'han tractat de forma independent malgrat que els seus continguts són complementaris. Amb la finalitat de treure un benefici d'aquesta vinculació es va decidir coordinar els seus programes. A més, per a potenciar la transferència de coneixements d'una assignatura a l'altra es proposa desenvolupar un projecte comú al llarg del curs. D'aquesta manera s'aconsegueix de forma més natural que AP i LP comparteixin un mateix fil argumental i a la vegada els alumnes adquireixen una visió més global dels fonaments de la programació. A l'inici del curs es proposa un enunciat genèric que presenta el projecte sense especificar què aportarà cada assignatura a la seva resolució. Els projectes que es plantegen intenten ser atractius pels alumnes per tal de motivar-los. Per això, bàsicament es proposa la programació de jocs. A mesura que el curs avança es van detallant els passos que cal seguir a nivell de disseny (AP) i a nivell d'implementació (LP) per a construir la solució final. La implementació d'aquesta metodologia ha estat molt satisfactòria i s'ha observat un major interès per part dels alumnes. A més, ha descendit el nombre de no presentats i ha pujat el nombre d'aprovats i la nota mitjana. In this work we describe part of the process carried out to adapt to the EEES two subjects (Algorithms and Programming - AP and Programming Languages - LP) of the degree on Computer Science at UAB. The adaptation is based on the utilization of a Project-Based Learning methodology.AP is a subject devoted to explain the theoretical basis of the analysis and design of algorithms, whereas LP applies these theoretical concepts using the C programming language. In the past, both subjects were seen as independent units although their contents are clearly complementary. In order to exploit this complementarity we decided to work towards a greater coordination of activities. The basis of this coordination is the development of a common programming project along all the semester. In this way, both subjects share the same piece of work and the students can acquire a global view of the programming basis. At the beginning of the semester we propose a generic problem that the students must solve and implement. We try to propose projects that can be appealing and motivating to the students. A good source of inspiration for that is programming videogames. As the semester advances we provide more details about the work to be done at the level of the design of the algorithm (AP) and at the level of programming in C (LP). The results of using this methodology are quite satisfactory. We have observed a greater interest and motivation of the students. Besides we have also quantitatively improved the academic results

Las cooperativas vinícolas bajo las dictaduras de Mussolini y Franco

Este articulo analiza las consecuencias de la intervencion estatal sobre las cooperativas vinicolas bajo los regimenes autoritarios de Mussolini en Italia y de Franco en Espana hasta los afios 1950. Se argumenta que el caracter de la intervencion fue bastante similar en ambos paises, puesto que el re­gimen franquista tome la organizacion corporativa del regimen fascista como modelo, si bien las consecuencias de la accion del Estado fueron mas profundas en el caso de Espana, fundamental­mente por la mayor duracion del regimen de Franco y tambien porque la gran expansion de! coope­rativismo vitivinicola se produjo en Espana durante el Franquismo

Phosphotyrosine proteins in platelets from patients with storage pool disease: direct relation between granule defects and defective signal transduction

Background and objectives: storage pool diseases (SPD) are heterogeneous disorders associated with an abnormal presence of intraplatelet granules, which cause mild to moderate bleeding diathesis. We investigated signaling through tyrosine phosphorylation of proteins occurring in platelets with total or partial absence of dense- and alpha-granules in response to activation. Design and methods: we included a patient with severe delta-SPD, a patient with severe alpha-SPD or gray platelet syndrome, and six patients with partial deficiency of dense or a-granules. SPD was confirmed by electron microscopy evaluation of platelet ultrastructure. Platelet function was evaluated by bleeding time determination and conventional aggregometry. Platelet suspensions were activated with collagen and thrombin to analyze changes in tyrosine phosphorylation of proteins by electrophoresis and Western-blotting. Results: bleeding times were prolonged in all the patients included. Aggregation responses were slightly decreased in delta-SPD and normal in the rest of patients. Tyrosine phosphorylation in platelets from patients with partial forms of SPD was equivalent to that observed in control platelets, absent in response to collagen and thrombin activation in delta-SPD, and deficient only to thrombin activation in alpha-SPD. Interpretation and conclusions: tyrosine phosphorylation of proteins in activated platelets is highly dependent on the substances contained in the dense-granules and moderately dependent on those contained in the alpha-granules. A minimum amount of intraplatelet granules ensures signaling through tyrosine phosphorylation of proteins

Salivary secretory disorders, inducing drugs, and clinical management

Background: Salivary secretory disorders can be the result of a wide range of factors. Their prevalence and negative effects on the patient's quality of life oblige the clinician to confront the issue. Aim: To review the salivary secretory disorders, inducing drugs and their clinical management. Methods: In this article, a literature search of these dysfunctions was conducted with the assistance of a research librarian in the MEDLINE/PubMed Database. Results: Xerostomia, or dry mouth syndrome, can be caused by medication, systemic diseases such as Sjögren's Syndrome, glandular pathologies, and radiotherapy of the head and neck. Treatment of dry mouth is aimed at both minimizing its symptoms and preventing oral complications with the employment of sialogogues and topical acting substances. Sialorrhea and drooling, are mainly due to medication or neurological systemic disease. There are various therapeutic, pharmacologic, and surgical alternatives for its management. The pharmacology of most of the substances employed for the treatment of salivary disorders is well-known. Nevertheless, in some cases a significant improvement in salivary function has not been observed after their administration. Conclusion: At present, there are numerous frequently prescribed drugs whose unwanted effects include some kind of salivary disorder. In addition, the differing pathologic mechanisms, and the great variety of existing treatments hinder the clinical management of these patients. The authors have designed an algorithm to facilitate the decision making process when physicians, oral surgeons, or dentists face these salivary dysfunctions