Crystallization and melting of bacteria colonies and Brownian Bugs

Motivated by the existence of remarkably ordered cluster arrays of bacteria colonies growing in Petri dishes and related problems, we study the spontaneous emergence of clustering and patterns in a simple nonequilibrium system: the individual-based interacting Brownian bug model. We map this discrete model into a continuous Langevin equation which is the starting point for our extensive numerical analyses. For the two-dimensional case we report on the spontaneous generation of localized clusters of activity as well as a melting/freezing transition from a disordered or isotropic phase to an ordered one characterized by hexagonal patterns. We study in detail the analogies and differences with the well-established Kosterlitz-Thouless-Halperin-Nelson-Young theory of equilibrium melting, as well as with another competing theory. For that, we study translational and orientational correlations and perform a careful defect analysis. We find a non standard one-stage, defect-mediated, transition whose nature is only partially elucidated.Comment: 13 Figures. 14 pages. Submitted to Phys. Rev.

Efecto sobre la calidad de la leche, características tecnológicas y producción quesera de la raza merina de grazalema frente al cruce con razas mejoradas

En los últimos años se están incorporando masivamente en España, en general y Andalucía en particular, razas ovinas foráneas de aptitud lechera, fundamentalmente las razas Assaf, Awassi y Lacaune. Su introducción está fomentando asimismo, la realización de cruces indiscriminados con nuestras razas ovinas autóctonas, de aptitud lechera pero de menor especialización, al menos cuantitativamente (Casas et al., 2005). El objetivo de este estudio ha sido analizar en dos grupos de animales de un mismo rebaño (ovejas puras de raza Merina de Grazalema, y ovejas cruzadas Merina de Grazalema x Awassi) las características de la producción lechera, y proceder a la elaboración de quesos para estudiar las posibles Consejería de Agricultura y Pesca 34 diferencias tecnológicas de los quesos derivados de ambas elaboraciones. A través del mismo se ha comprobado una mayor producción lechera de las ovejas cruzadas (167,35±13,20 kg frente a 136,84±4,25 kg) pero con un porcentaje de grasa (6,25±0,34 % frente a 8,27±0,22 %), proteína (4,71±0,14 % frente a 5,80±0,09 %) y extracto seco (10,97±0,46 % frente a 14,07±0,28 %) estadísticamente inferior. En cuanto a los parámetros de aptitud tecnológica, los valores de tiempo de coagulación medio (24,70±0,77 minutos), dureza media (dureza del coágulo a los 30 minutos) de 25,03±2,27 mm, y el rendimiento en cuajada (327,50±5,70 g/l), mostraron cifras inferiores a las referenciadas por Casas et al. (2005) para la raza ovina Merina de Grazalema. Finalmente, la velocidad de endurecimiento resultó mayor a los valores obtenidos en el trabajo citado anteriormente (4,59±0,54 min). Por otro lado, estos mismos parámetros mostraron valores inferiores en el tiempo de coagulación (19,60±0,62 minutos), velocidad de endurecimiento (3,97±0,38 min) y rendimiento en cuajada (290,55±6,67), mientras que la dureza media (32,85±2,03 mm) fue superior en las ovejas cruzadas, respecto a los valores encontrados en esta misma explotación para los animales puros. Como consecuencia de todo ello, el rendimiento quesero real fue del 30,25 % para las ovejas puras frente al 23,70 % de las cruzadas. Esto determina que la producción quesera real que se obtiene por oveja pura, sea superior al de la cruzada (41,38 kg queso fresco/ lactación frente a los 39,70 de la cruzada).Proyecto INIA. Ministerio de Educación y Ciencia

Gaidropsarus gallaeciae (Gadiformes: Gaidropsaridae), a New Northeast Atlantic Rockling Fish, with Commentary on the Taxonomy of the Genus

A new species of rockling fish genus Gaidropsarus is described based on six specimens collected in Galicia and Porcupine Banks, in Atlantic European waters. An analysis of morphological characters has confirmed the specific status of specimens of a previously described clade by comparison of DNA sequences. Gaidropsarus gallaeciae sp. nov. it is distinguished from congeners by the following combination of characters: 43–44 vertebrae; 54–60 third dorsal fin rays; 44–52 anal fin rays; 21–23 pectoral fin rays; head length 21.1–25.2% of standard length (SL); length of the pelvic fin 16.2–19% SL; length of the first dorsal fin ray 15.8–27% of head length (%HL); eye diameter 15.8–20.5% HL; and interorbital space 21.7–28% HL. Using the nucleotide sequence of the 5’ end of the mitochondrial COI gene as a molecular marker, the genetic p-distance between the new species and its congeners far exceeds the usual 2%, granting the former the status of an independent taxon, which is in accordance with the morphological identification. A comparison with the other 12 valid species of the genus is presented. The study also highlights the morphological diversity resulting from the meristic and biometric variability of Gaidropsarus species and lays the groundwork for future taxonomic studies on this genus.Versión del editor5,82

Anaerobic co-digestion of pear residues and sewage sludge using a CSTR digester. Influence of the feed procedure

Anaerobic co-digestion of pear residues with sewage sludge is feasible. Important differences are obtained from the two feed regimes tested, with better results for the so-called continuous feed. The organic loading rate (OLR) is the important parameter for the methane productionUniversidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Strong coupling between weakly guided semiconductor nanowire modes and an organic dye

The light-matter coupling between electromagnetic modes guided by a semiconductor nanowire and excitonic states of molecules localized in its surrounding media is studied from both classical and quantum perspectives, with the aim of describing the strong-coupling regime. Weakly guided modes (bare photonic modes) are found through a classical analysis, identifying those lowest-order modes presenting large electromagnetic fields spreading outside the nanowire while preserving their robust guided behavior. Experimental fits of the dielectric permittivity of an organic dye that exhibits excitonic states are used for realistic scenarios. A quantum model properly confirms through an avoided mode crossing that the strong-coupling regime can be achieved for this configuration, leading to Rabi splitting values above 100 meV. In addition, it is shown that the coupling strength depends on the fraction of energy spread outside the nanowire, rather than on the mode field localization. These results open up a new avenue towards strong-coupling phenomenology involving propagating modes in nonabsorbing media.The authors acknowledge the Spanish Ministerio de Economía, Industria y Competitividad for financial support through Grants No. MAT2014-53432-C5-5-R, No. FIS2015-69295-C3-2-P, and No. FIS2017-91413-EXP; the María de Maeztu program for Units of Excellence in R&D (MDM-2014-0377); and an FPU Fellowship (D.R.A.) and a Ramón y Cajal grant (J.F.). We also acknowledge funding from the European Research Council (ERC-2016-STG-714870

Using Location-Allocation Algorithms to Distribute Multioutlet Hydrants in Irrigation Networks Design

Location-allocation algorithms allow for situating services in an efficient way in zones where the demand is dispersed across the area. In the present work, the minisum location-allocation algorithm is used to optimize the placement multioutlet hydrants, which are needed to supply irrigation to the region. The objective function aims to minimize the total access costs of the service. Because the total number of hydrants is the same as what currently exists the results can be compared with the presented solution. The proposed model reduces the total distance run to access the service, from 16,177 m to 13,560 m (16.17%), and the objective function (proportional to the cost) by 28.95%. © 2012 American Society of Civil Engineers.González Villa, FJ.; García Prats, A. (2011). Using Location-Allocation Algorithms to Distribute Multioutlet Hydrants in Irrigation Networks Design. Journal of Irrigation and Drainage Engineering. 274-283. doi:10.1061/(ASCE)IR.1943-4774.0000405S27428

Ultrahigh-quality factor resonant dielectric metasurfaces based on hollow nanocuboids

In this work, a dielectric metasurface consisting of hollow dielectric nanocuboids, with ultrahigh quality factor, is theoretically proposed and demonstrated. The variation of the hole size of the cuboid allows for the tuning of the resonant anapole mode in the nanoparticles. The metasurface is designed to operate in two complementary modes, namely electromagnetically induced transparency and narrowband selective reflection. Thanks to the non-radiative nature of the anapole resonances, the minimal absorption losses of the dielectric materials, and the near-field coupling among the metasurface nanoparticles, a very high quality factor of =2.5×106 is achieved. The resonators are characterized by a simple bulk geometry and the subwavelength dimensions of the metasurface permit operation in the non-diffractive regime. The high quality factors and strong energy confinement of the proposed devices open new avenues of research on light-matter interactions, which may find direct applications, e.g., in non-linear devices, biological sensors, laser cavities, and optical communications.Research and Development Program through the Comunidad de Madrid (SINFOTON S2013/MIT-2790); Ministerio de Economia y Competitividad of Spain (TEC2013-47342-C2-2-R); mobility programs of Carlos III University and "Jose Castillejo" of the Ministerio de Educacion, Cultura y Deporte of Spain