The Contagion Effects of Repeated Activation in Social Networks

Demonstrations, protests, riots, and shifts in public opinion respond to the coordinating potential of communication networks. Digital technologies have turned interpersonal networks into massive, pervasive structures that constantly pulsate with information. Here, we propose a model that aims to analyze the contagion dynamics that emerge in networks when repeated activation is allowed, that is, when actors can engage recurrently in a collective effort. We analyze how the structure of communication networks impacts on the ability to coordinate actors, and we identify the conditions under which large-scale coordination is more likely to emerge.Comment: Submitted for publicatio

Improvement of InAs quantum dots optical properties in close proximity to GaAs(0 0 1) substrate surface

5 páginas, 4 figuras.-- PACS codes: 78.67.Hc; 81.05.Ea; 81.07.Ta; 81.15.Hi; 81.16.DnIn this work we demonstrate a growth process for obtaining high optical emission efficiency InAs/GaAs(0 0 1) quantum dots (QD) formed at short distance to the interface with the GaAs substrate. In particular, after an initial exposure of the substrate surface to long times of atomic hydrogen flux (tH up to 45 min) followed by a posterior growth of a GaAs buffer layer by atomic layer molecular beam epitaxy, both steps at low substrate temperature (TS=450 °C), an enhancement of InAs QD optical emission efficiency is obtained, even at close proximity (3.5 nm) to the substrate interface. This process fulfils the strict requirements in terms of substrate temperature and buffer layer thickness (distance from the QD to the substrate interface) for its possible use as an optimal regrowth protocol on previously patterned GaAs substrates.This work was financed by Spanish MEC(TEC2005-05781-C03- 01,NAN2004-09109-C04-01,Consolider-Ingenio 2010CSD2006- 00019),CAM (S 0505ESP0200)and by the SANDIE Network of excellence(Contract no. NMP4-CT-2004-500101 group TEP-0120). JMS and PAG thank the I3Pprogram.Peer reviewe

Study of the preparation process and variation of wall components in chia (Salvia hispanica L.) oil microencapsulation

A study of the microencapsulation process of omega-3 rich oil extracted from chia (Salvia hispanica L.) seeds was carried out, which included a comparative analysis of the microcapsules obtained by the spray- and freeze-drying methods using isolated soy proteins and maltodextrin as wall materials at different proportions. Color characterization of the obtained powders was performed and revealed a darker and yellower appearance of the freeze-dried samples compared with the spray-dried ones. Moisture content was measured for each sample and all presented values around 3.5%. The SEM micrographs revealed that spray-dried microcapsules can occur individually or may form clusters or aggregates, with the particles exhibiting a size range varying from 4 to 10 µm. Encapsulation efficiency was measured, with no significant differences found between drying methods or on varying the proportion of wall components (all samples presented values of aproximately 60%). The oxidative stability of microencapsulated oils under accelerated oxidative conditions revealed protection factors 2-fold higher for all samples. In addition, microencapsulated oil stored under 25 ºC revealed lower hydroperoxide values than those of unencapsulated oil throughout the whole storage test. Finally, oil encapsulated in SPI microcapsules also showed lower HPV values than that of the acceptable limit for virgin and cold-pressed vegetable oils (15 meq. O2/kg oil) during the storage test, while unencapsulated oil attained the acceptable limit in 62 days. This result represents an increase in the time of the oil shelf life of between 30 and 48%.Fil: González, Agustín. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Ciencia y Tecnología de Alimentos Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Ciencia y Tecnología de Alimentos Córdoba; ArgentinaFil: Martinez, Marcela Lilian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Paredes, Alejandro Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Unidad de Investigación y Desarrollo en Tecnología Farmacéutica. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Unidad de Investigación y Desarrollo en Tecnología Farmacéutica; ArgentinaFil: Leon, Alberto Edel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Ciencia y Tecnología de Alimentos Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Ciencia y Tecnología de Alimentos Córdoba; ArgentinaFil: Ribotta, Pablo Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Ciencia y Tecnología de Alimentos Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Ciencia y Tecnología de Alimentos Córdoba; Argentin

Ultrasound-Guided Percutaneous Neuromodulation in Multiple Sclerosis: A Case Report

Multiple sclerosis is a degenerative inflammatory disease that causes different musculoskeletal problems. Its impact has led to the study of treatment alternatives such as the use of invasive physiotherapy. In this study, we analyze the effects of ultrasound-guided percutaneous neuromodulation to a 51-year-old man suffering from multiple sclerosis and an associated hemiparesis in the left upper limb. A dry needling needle was placed in contact with the median nerve under ultrasound guidance and 10 trains of 10 seconds of electrostimulation with a frequency of 10 Hz and an impulse width of 240 µs were applied, with 10 seconds of pause between them. There was a significant improvement in the grip strength immediately after the treatment which increased progressively at 24 hours and at 4 days follow-up. There was also an improvement in the hand function, with a decrease in the time necessary to perform the 9 Hole Peg Test immediately after the treatment, which was maintained at 24 hours and at 4 days follow-up. Future studies with larger samples are needed to further test the effects of this invasive physiotherapy technique as well as its possible applications to other neurological conditions

Joint denoising and decompression using CNN regularization

International audienceWavelet compression schemes (such as JPEG2000) lead to very specific visual artifacts due to the quantization of noisy wavelet coefficients. They have highly spatialy-correlated structure that makes it difficult to be removed with standard denoising algorithms. In this work, we propose a joint denoising and decompression method that combines a data-fitting term which takes into account the quantization process and an implicit prior contained in a stateof-the-art denoising CNN

Investigación cualitativa asistida por ordenador en economía de la empresa

El interés por la comprensión holística de las organizaciones se manifiesta en la proliferación de artículos basados en metodologías cualitativas. Este hecho no se ve acompañado con el empleo de herramientas que contribuyan a la validez y fiabilidad de las investigaciones. Este trabajo pone de manifiesto la existencia de programas específicos para el tratamiento de datos cualitativos y explica la contribución que realizan en las diferentes fases del proceso de investigación. También analiza las ventajas e inconvenientes que se derivan de su uso y reflexiona acerca de su repercusión en la investigación de la Economía de la Empresa

Nanoóptica: controlando la luz en la nanoescala

La localización de la luz en diversas nanoestructuras ha permitido superar los límites de la óptica convencional, posibilitando un control sin precedentes de diversos procesos optoelectrónicos. La comprensión de la interacción entre la luz y la materia en la nanoescala sienta las bases de la generación, control, y manipulación de haces de luz en espacios ínfimos, abriendo un nuevo abanico de posibilidades tecnológicas. Entre otras, la nanoóptica permite obtener imagenes nanoscópicas de nanopartículas y sustancias biológicas, transmitir señal óptica de alta densidad en dispositivos, realizar termoterapia contra células cancerígenas o mejorar las prestaciones de células solares.Peer Reviewe

Drops with non-circular footprints

In this paper we study the morphology of drops formed on partially wetting substrates, whose footprint is not circular. This type of drops is a consequence of the breakup processes occurring in thin films when anisotropic contact line motions take place. The anisotropy is basically due to hysteresis effects of the contact angle since some parts of the contact line are wetting, while others are dewetting. Here, we obtain a peculiar drop shape from the rupture of a long liquid filament sitting on a solid substrate, and analyze its shape and contact angles by means of goniometric and refractive techniques. We also find a non--trivial steady state solution for the drop shape within the long wave approximation (lubrication theory), and compare most of its features with experimental data. This solution is presented both in Cartesian and polar coordinates, whose constants must be determined by a certain group of measured parameters. Besides, we obtain the dynamics of the drop generation from numerical simulations of the full Navier--Stokes equation, where we emulate the hysteretic effects with an appropriate spatial distribution of the static contact angle over the substrate

Evolution of the Hurdle-Unit Kinematic Parameters in the 60 m Indoor Hurdle Race.

The aims of this study were to compare the five hurdle-unit split times from the deterministic model with the hurdle-to-hurdle model and with the official time, to compare the step kinematics of each hurdle-unit intervals, and to relate these variables to their respective hurdle-unit split times. The temporal and spatial parameters of the 60 m hurdles race were calculated during the 44th Spanish and 12th IAAF World Indoor Championships (men: n = 59; women: n = 51). The hurdle-unit split times from the deterministic model showed a high correlation (r = 0.99; p < 0.001) with the split times of the hurdle-to-hurdle model and faster split times were related to shorter step and flight times in hurdle steps for both genders. At the first hurdle, male athletes tended to increase their flight and contact times while the tendency of female athletes was to decrease their contact and flight times. In addition, at the first hurdle, both genders presented shorter take-off distance, shorter landing distance, and greater step width than in the remaining hurdles of the race. Therefore, coaches should implement training programs that have an impact on these key variables according to the specific demands of each hurdle-unit phase and gender.post-print2650 K