2,188 research outputs found
Influence of the Surface Viscosity on the Breakup of a Surfactant-Laden Drop
We examine both theoretically and experimentally the breakup of a pendant drop loaded with an
insoluble surfactant. The experiments show that a significant amount of surfactant is trapped in the resulting
satellite droplet. This result contradicts previous theoretical predictions, where the effects of surface tension
variation were limited to solutocapillarity and Marangoni stresses.We solve numerically the hydrodynamic
equations, including not only those effects but also those of surface shear and dilatational viscosities. We
show that surface viscosities play a critical role to explain the accumulation of surfactant in the satellite
droplet.Ministerio de Economía y Competitividad DPI2013-46485-C3-1-R, TRA2013- 45808-RJunta de Extremadura GR1004
Bacterial Ligase D preternary-precatalytic complex performs efficient abasic sites processing at double strand breaks during nonhomologous end joining
Abasic (AP) sites, the most common DNA lesions are frequently associated with double strand breaks (DSBs) and can pose a block to the final ligation. In many prokaryotes, nonhomologous end joining (NHEJ) repair of DSBs relies on a two-component machinery constituted by the ring-shaped DNA-binding Ku that recruits the multicatalytic protein Ligase D (LigD) to the ends. By using its polymerization and ligase activities, LigD fills the gaps that arise after realignment of the ends and seals the resulting nicks. Here, we show the presence of a robust AP lyase activity in the polymerization domain of Bacillus subtilis LigD (BsuLigD) that cleaves AP sites preferentially when they are proximal to recessive 5'-ends. Such a reaction depends on both, metal ions and the formation of a Watson¿Crick base pair between the incoming nucleotide and the templating one opposite the AP site. Only after processing the AP site, and in the presence of the Ku protein, BsuLigD catalyzes both, the in-trans addition of the nucleotide to the 3'-end of an incoming primer and the ligation of both ends. These results imply that formation of a preternary-precatalytic complex ensures the coupling of AP sites cleavage to the end-joining reaction by the bacterial LigDMinistry of Science, Innovation and Universities [BFU2017-83900-P AEI/FEDER UE to M.V.]; institutional grants from Fundacion Ramón Areces and Banco ´ de Santander to the Centro de Biología Molecular Severo Ocho
Breeding terrains with genetic terrain programming: the evolution of terrain generators
Although a number of terrain generation techniques have been proposed during the last few years, all of them have some
key constraints. Modelling techniques depend highly upon designer’s skills, time, and effort to obtain acceptable results, and
cannot be used to automatically generate terrains. The simpler methods allow only a narrow variety of terrain types and offer
little control on the outcome terrain. The Genetic Terrain Programming technique, based on evolutionary design with Genetic
Programming, allows designers to evolve terrains according to their aesthetic feelings or desired features. This technique evolves
Terrain Programmes (TPs) that are capable of generating a family of terrains—different terrains that consistently present the
same morphological characteristics. This paper presents a study about the persistence of morphological characteristics of terrains
generated with different resolutions by a given TP. Results show that it is possible to use low resolutions during the evolutionary
phase without compromising the outcome, and that terrain macrofeatures are scale invariant
Automatic evolution of programs for procedural generation of terrains for video games: accessibility and edge length constraints
Nowadays the video game industry is facing
a big challenge: keep costs under control as games become
bigger and more complex. Creation of game content,
such as character models, maps, levels, textures,
sound effects and so on, represent a big slice of total
game production cost. Hence, the video game industry
is increasingly turning to procedural content generation
to amplify the cost-effectiveness of the efforts of video
game designers. However, procedural methods for automated
content generation are difficult to create and
parametrize. In this work we study a Genetic Programming
based procedural content technique to generate
procedural terrains that do not require parametrization,
thus, allowing to save time and help reducing production
costs. Generated procedural terrains present aesthetic
appeal; however, unlike most techniques involving
aesthetic, our approach does not require a human to
perform the evaluation. Instead, the search is guided by
the weighted sum of two morphological metrics: terrain
accessibility and obstacle edge length. The combination of the two metrics allowed us to find a wide range of fit
terrains that present more scattered obstacles in different
locations, than our previous approach with a single
metric. Procedural terrains produced by this technique are already in use in a real video game
Genetic terrain programming: an aesthetic approach to terrain generation
Comunicação apresentada na conferência Computer Games and Allied Technology, 8, Singapore, 2008.Nowadays there are a wide range of techniques for terrain generation, but are focused on
providing realistic terrains often neglecting the aesthetic appeal. The Genetic Terrain
Programming technique, based on evolutionary design with Genetic Programming, allows
designers to evolve terrains according to their aesthetic feelings or desired features. This
technique evolves TPs (Terrain Programmes) that are capable of generating different terrains, but
consistently with the same features. This paper presents a study about the perseverance of
terrain features of the TPs across different LODs (Levels Of Detail). Results showed it is possible
to use low LODs during the evolutionary phase without compromising results and the terrain
features generated by a TPs are scale invariant
GenTP: uma ferramenta interactiva para a geração artificial de terrenos
Actualmente existe uma grande variedade de técnicas de geração
artificial de terrenos. No entanto todas elas estão focadas em fornecer
terrenos de aspecto realista, negligenciando por vezes a estética e a
criatividade. Este artigo apresenta uma ferramenta interactiva para a geração
artificial de terrenos, designada GenTP, inspirada nos sistemas de arte
evolutiva com programação genética. Esta ferramenta permite aos designers
evoluir TPs (Terrain Programs) de acordo com o seu sentido estético ou
características desejadas. Os TPs, o produto desta ferramenta, geram terrenos
diferentes a cada execução, mas sempre coerentes nas sua características
morfológicas
Aplicación de SFM-MVS con precisión mejorada para la restitución fotogramétrica y comparacion de las imágenes aéreas de archivo pre y post erupción en Isla Decepción (Shetland Del Sur, Antártida)
[EN] Despite today's extensive remote sensing imagery with all kinds of sensors, the use of old aerial imagery is still importantin the study of slowly evolving land processes to reconstruct past landscape forms. Numerous organisations sharephotogrammetric data in public repositories, offering opportunities to exploit them to identify historical, natural andanthropogenic topographic changes, which is particularly interesting if they are difficult to access areas, possibly affectedsince historic times by climate change and other geodynamic processes. This work proposes and applies a workflow basedon the SfM-MVS photogrammetric technique to 22 and 33 historical aerial photographs of the English FIDASE (1956/57)and Argentinean Navy (1968) flights, scanned at 1016dpi and 96dpi, black and white, of Deception Island (South Shetland,Antarctica). The photogrammetric processing controls the threshold values of the reconstruction uncertainties andprojection accuracy. The 3D point clouds obtained are geroreferenced with 37 ground control points (GCP) geographicallypositioned in a QuickBird2 satellite image over island areas not affected by volcanism. The quality of the DTM is controlledby comparison with the 1960 topographic map 1:25000 of the island, which allows the volumes of material emitted in thevolcanic eruption of 1967 to be evaluated. The results obtained improve considerably and extend the set of resultscompared to those obtained by classical contour line digitizing. The applied method, the DTM and orthomosaic of 1956and 1968 presented will allow us to evaluate, together with the analysis applied to later historical flights, English 1979 andChilean 1986, the recent changes produced by the recent volcanism, the local external geodynamics, the possible climaticdeterioration and the scope of current human activity from 1956 to the present day.[ES] A pesar de la actualmente minuciosa toma de imágenes con sensores de todo tipo, la utilización de antiguas imágenes
aéreas sigue siendo importante en el estudio de procesos del terreno de evolución lenta para reconstruir las formas
pasadas del paisaje. Numerosas administraciones comparten los datos fotogramétricos en depósitos públicos, ofreciendo
oportunidades para explotarlos y detectar cambios topográficos históricos naturales y antropogénicos, lo cual resulta ser
de mayor interés si son zonas de difícil acceso, posiblemente afectadas desde tiempos pretéritos por el cambio climático
y otros procesos geodinámicos. Este trabajo, propone y aplica un flujo de trabajo basado en la técnica fotogramétrica SfMMVS a 22 y 33 fotos aéreas históricas de los vuelos inglés FIDASE (1956/57) y de la Armada Argentina (1968),
escaneadas a 1016ppp y 96ppp, en blanco y negro, de la Isla Decepción (Shetland del Sur, Antártida). El procesado
fotogramétrico controla los valores umbral de las incertidumbres de la reconstrucción y precisiones de proyección. Las
nubes de puntos 3D obtenidas son gerorreferenciadas con 37 puntos de control terrestre (GCP) geográficamente
posicionados en una imagen QuickBird2 sobre zonas no afectadas por vulcanismo. La calidad de los MDE se controla
comparándolo con el mapa topográfico 1:25000 de la Isla lo que permite evaluar los volúmenes de material emitido en la
erupción volcánica de 1967. Los resultados obtenidos mejoran notablemente y extienden el conjunto de resultados frente
los obtenidos por digitalización clásica de las curvas de nivel. El método aplicado, los MDE y ortomosaico de 1956 y 1968
presentados permitirán evaluar, junto con el análisis aplicado a vuelos históricos posteriores, inglés de 1979 y chileno de
1986, los cambios recientes producidos por el volcanismo reciente, la geodinámica externa local, el posible deterioro
climático y ámbito de afección de la actividad humana actual desde 1956 hasta la actualidad.This work has been developed within the Project "Auscultación de procesos activos sobre la ladera y la costa acantilada del entorno próximo de la Base Antártica Española Gabriel de Castilla" of the INTA - Ejército de Tierra financed by the Ministry of Defence and collaboration with UPM. The authors are grateful for the support received from the BGC staff, the Antarctic Campaign Office and the Logistics Division of the Army General Staff, the Hydrographic Institute of the Navy (IHM), Spanish Polar Committee (CPE), and Universities.Paredes, C.; De La Vega-Panizo, R.; Ropero, M. (2021). Application of improved accuracy SFM-MVS for photogrammetric restitution and comparison of pre- and post-eruption archival aerial imagery on Deception Island (South Shetland, Antarctica). En Proceedings 3rd Congress in Geomatics Engineering. Editorial Universitat Politècnica de València. 15-25. https://doi.org/10.4995/CiGeo2021.2021.12755152
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