Mundos virtuales y reales. Estudio de la integración de la realidad aumentada y virtual en educación formal

Tesis doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Formación de Profesorado y Educación, Departamento de Didáctica y Teoría de la Educación. Fecha de lectura: 8-09-201

A new Colombian pest species of the genus \u3ci\u3ePoecilocloeus\u3c/i\u3e Bruner (Orthoptera: Acrididae: Proctolabinae) on coffee, with a key to the Neotropical species

A remarkable new species of Poecilocloeus (Orthoptera: Acrididae: Proctolabinae) found damaging coffee plantations in the Western Andes of Colombia is described and named P. coffeaphilus n. sp. This new species is part of a distinct and colorful group of Proctolabinae grasshoppers, with most species found at low altitudes in the rainforest of the Amazon basin. In contrast, the new species is found at elevations of 1600 to 1800 m in the canopy of dense cloud forests, in the southwestern part of the department of Antioquia (Western Cordillera, Colombian Andes). Information about the natural history, behavior, natural enemies and control strategies in coffee plantations is given for this new species of masked grasshopper. A key to the Neotropical species of the fruticolus species group is presented. Una nueva y notable especie de Poecilocloeus (Orthoptera: Acrididae: Proctolabinae) encontrada afectando plantaciones de café en la cordillera occidental de Colombia es descrita y nombrada como P. coffeaphilus. La nueva especie hace parte de un grupo distintivo y colorido de saltamontes de la subfamilia Proctolabinae, con la mayoría de especies distribuidas a bajas altitudes en las selvas lluviosas de la cuenca amazónica. Por el contrario, la nueva especie se encuentra a altitudes entre 1.600 a 1.800 m en el dosel del bosque nublado, en el suroeste del departamento de Antioquia (Andes colombianos, Cordillera Occidental). Se da información acerca de la historia natural, comportamiento, enemigos naturales y estrategias de control de esta nueva especie de saltamonte enmascarado en cultivos de café. Se presenta una clave para las especies del grupo fruticolus de la región Neotropical

Full capacitance-matrix effects in driven Josephson-junction arrays

We study the dynamic response to external currents of periodic arrays of Josephson junctions, in a resistively capacitively shunted junction (RCSJ) model, including full capacitance-matrix effects}. We define and study three different models of the capacitance matrix $C_{\vec{r},\vec{r}'}$: Model A includes only mutual capacitances; Model B includes mutual and self capacitances, leading to exponential screening of the electrostatic fields; Model C includes a dense matrix $C_{\vec{r},\vec{r}'}$ that is constructed approximately from superposition of an exact analytic solution for the capacitance between two disks of finite radius and thickness. In the latter case the electrostatic fields decay algebraically. For comparison, we have also evaluated the full capacitance matrix using the MIT fastcap algorithm, good for small lattices, as well as a corresponding continuum effective-medium analytic evaluation of a finite voltage disk inside a zero-potential plane. In all cases the effective $C_{\vec{r},\vec{r}'}$ decays algebraically with distance, with different powers. We have then calculated current voltage characteristics for DC+AC currents for all models. We find that there are novel giant capacitive fractional steps in the I-V's for Models B and C, strongly dependent on the amount of screening involved. We find that these fractional steps are quantized in units inversely proportional to the lattice sizes and depend on the properties of $C_{\vec{r},\vec{r}'}$. We also show that the capacitive steps are not related to vortex oscillations but to localized screened phase-locking of a few rows in the lattice. The possible experimental relevance of these results is also discussed.Comment: 12 pages 18 Postscript figures, REVTEX style. Paper to appear in July 1, Vol. 58, Phys. Rev. B 1998 All PS figures include

Cyst-theca relationships of Gonyaulacales and Peridiniales (Dinophyceae) from Bahía Concepción, Gulf of California

Based on samples obtained in 2000-2002 from a 1-cm layer of surface sediment at two sites in Bahía Concepción in the Gulf of California, cyst-theca relationships were defined from cyst germination assays for Gonyaulax spinifera (= Spiniferites mirabilis), Protoce- ratium globosum, Preperidinium meunieri (= Dubridinium caperatum), Protoperidinium denticulatum (= Brigantedinium irregulare), and Protoperidinium cf. thorianum. All the taxa are illustrated with photomicrographs and descriptions of the resting and vegetative stages are given, including synonymy, size variation, distribution in Mexico, and global distribution, when known. As a result of cyst germination assays, the previously unknown cyst-theca relationship of P. globosum was described. We also confirmed the presence of the vegetative stage of P. denticulatum in the Gulf of California and heterospory in G. spinifera from Bahía Concepción. Cultures of G. spinifera and P. globosum were successfully established.Mediante ensayos de germinación se logró definir la relación quiste-teca de Gonyaulax spinifera (= Spiniferites mirabilis), Protoceratium globosum, Preperidinium meunieri (= Dubridinium caperatum), Protoperidinium denticulatum (= Brigantedinium irregulare) y Protoperidinium cf. thorianum. Los quistes se aislaron a partir del primer centímetro de sedimento superficial de muestras colectadas durante el periodo 2000-2002 en Bahía Concepción, Golfo de California. Los taxa identificados se ilustran con microfotografias, se describe la morfología de los estadios quístico y vegetativo, y también se incluye información sobre sinonimias, variación en talla y su distribución en México y en el mundo. Los ensayos de germinación permitieron describir por primera vez la relación quiste-teca de P. globosum, confirmar la presencia del estadio vegetativo de P. denticulatum en el Golfo de California y de la heterosporia en G. spinifera. También se establecieron con éxito cepas de G. spinifera y P. globosum

Pauli principle and chaos in a magnetized disk

We present results of a detailed quantum mechanical study of a gas of $N$ noninteracting electrons confined to a circular boundary and subject to homogeneous dc plus ac magnetic fields $(B=B_{dc}+B_{ac}f(t)$, with $f(t+2\pi/\omega_0)=f(t)$). We earlier found a one-particle {\it classical} phase diagram of the (scaled) Larmor frequency $\tilde\omega_c=omega_c/\omega_0$ {\rm vs} $\epsilon=B_{ac}/B_{dc}$ that separates regular from chaotic regimes. We also showed that the quantum spectrum statistics changed from Poisson to Gaussian orthogonal ensembles in the transition from classically integrable to chaotic dynamics. Here we find that, as a function of $N$ and $(\epsilon,\tilde\omega_c)$, there are clear quantum signatures in the magnetic response, when going from the single-particle classically regular to chaotic regimes. In the quasi-integrable regime the magnetization non-monotonically oscillates between diamagnetic and paramagnetic as a function of $N$. We quantitatively understand this behavior from a perturbation theory analysis. In the chaotic regime, however, we find that the magnetization oscillates as a function of $N$ but it is {\it always} diamagnetic. Equivalent results are also presented for the orbital currents. We also find that the time-averaged energy grows like $N^2$ in the quasi-integrable regime but changes to a linear $N$ dependence in the chaotic regime. In contrast, the results with Bose statistics are akin to the single-particle case and thus different from the fermionic case. We also give an estimate of possible experimental parameters were our results may be seen in semiconductor quantum dot billiards.Comment: 22 pages, 7 GIF figures, Phys. Rev. E. (1999

Serological evaluation of bovine herpesvirus 1 and 5 in cattle-breeding systems on Colombia’s high plains

Objective. The aim of this study was to determine the presence of Bovine herpesvirus – 1 (BoHV- 1) and Bovine herpesvirus 5 (BoHV-5) neutralizing antibodies in herds on the Colombian high plains and their correlation with the level of cross-protection against both herpesviruses. Materials and methods. This study was carried out on cattle farms located around the towns of Puerto López and Puerto Gaitán in Colombia’s Meta department. Sampling was made by convenience. Twenty-three farms were involved in the study; 488 sera samples were taken by random sampling. Virus neutralization test were performed according to the protocols of the OIE. Each serum was evaluated independently for each virus, BoHV-1 and BoHV-5. Results. The serological test confirmed the presence of BoHV-1 and BoHV-5 infections in the Colombian bovine population in 100% and 73.9% respectively. However, crossreaction for both viruses was not evident in all farms evaluated. Conclusions. Alpha-herpesviruses are amongst the most significant infectious agents affecting cattle. Bovine herpesvirus 1 (BoHV-1) is found throughout the whole world and is endemic in Colombian bovine population, whereas bovine herpesvirus 5 (BoHV-5) has limited geographical distribution, mainly being reported in South-America (Brazil and Argentina), and we also confirmed the presence of BoHV-5 in Colombia. Objetivo. El objetivo de este estudio fue determinar la presencia de anticuerpos para herpesvirus bovino 1 (BoHV-1) y herpesvirus bovino 5 (BoHV-5), así como también determinar el nivel de protección cruzada contra los dos herpesvirus en hatos de la altillanura colombiana. Materiales y métodos. Este estudio se realizó en fincas ubicadas en los municipios de Puerto López y Puerto Gaitán departamento del Meta. Se realizó un muestreo por conveniencia. Se emplearon 23 fincas, donde se realizó un muestreo al azar en cada una para un total de 488 muestras. Las muestras de suero fueron analizadas mediante sero-neutralización viral empleando los protocolos de la OIE. Cada uno de los sueros fue evaluado de manera independiente para cada uno de los virus BoHV-1 y BoHV-5. Resultados. Mediante la sero-neutralización viral se confirmó la presencia de BoHV-1 y BoHV-5 en la población bovina colombiana en 100% y 73.9%, respectivamente. Sin embargo, la reactividad 2016 cruzada no fue evidente en todas las fincas evaluadas. Conclusiones. Los alfa-herpesvirus bovinos se encuentran entre los agentes infecciosos más importantes del ganado bovino. Particularmente, el herpesvirus bovino 1 (BoHV-1) presenta una distribución mundial, siendo endémico en la población bovina colombiana, mientras que el herpesvirus bovino 5 (BoHV-5), presenta una distribución geográfica limitada; reportándose principalmente en Suramérica (Brasil y Argentina), comprobándose la presencia de este en los hatos colombianos

In vitro Induction of Entamoeba histolytica Cyst-like Structures from Trophozoites

Inhibition of encystment can be conceived as a potentially useful mechanism to block the transmission of Entamoeba histolytica under natural conditions. Unfortunately, amoeba encystment has not been achieved in vitro and drugs inhibiting the formation of cysts are not available. Luminal conditions inducing encystment in vivo are also unknown, but cellular stress such as exposure to reactive oxygen species from immune cells or intestinal microbiota could be involved. A role for certain divalent cations as cofactors of enzymes involved in excystment has also been described. In this study, we show that trophozoite cultures, treated with hydrogen peroxide in the presence of trace amounts of several cations, transform into small-sized spherical and refringent structures that exhibit resistance to different detergents. Ultrastructural analysis under scanning and transmission electron microscopy revealed multinucleated structures (some with four nuclei) with smooth, thick membranes and multiple vacuoles. Staining with calcofluor white, as well as an ELISA binding assay using wheat germ agglutinin, demonstrated the presence of polymers of N-acetylglucosamine (chitin), which is the primary component of the natural cyst walls. Over-expression of glucosamine 6-phosphate isomerase, likely to be the rate-limiting enzyme in the chitin synthesis pathway, was also confirmed by RT-PCR. These results suggest that E. histolytica trophozoites activated encystment pathways when exposed to our treatment

Seasonal and spatial variability in condition of age-0+ Argentine hake Merluccius hubbsi Marini, 1933, in the San Jorge Gulf (Argentina): A bottom-up perspective

In the north Patagonian region of the Argentinean Continental Shelf, the San Jorge Gulf (SJG; 45°‐47°S, 65°30ʹ‐67°30ʹW) is the main nursery ground of age‐0+ Argentine hake Merluccius hubbsi Marini, 1933, one of the most important fishery resources in Argentina. The gulf exhibits strong seasonal and spatial fluctuations in environmental features, which might affect survival of age‐0+ individuals and recruitment to the adult population. Our main goal was to evaluate the seasonal and spatial dynamics of their nutritional status within the SJG in winter 2016, spring 2016 and summer 2017. Condition indices (relative condition factor Kn, hepatosomatic index HSI and liver lipid content %L) and diet information (feeding incidence and relative importance of prey) were combined with physical (temperature and salinity) and biological (satellite chlorophyll‐a concentration; chl‐a) data. Age‐0+ condition indices and prey intake showed significant seasonal variations, with minimum values in winter, intermediate in summer and maximum in spring, strongly coupled to the mean chl‐a concentration in each season. Herbivorous euphausiids Euphausia spp. were the preferred prey along the study period. A bottom‐up effect on condition of age‐0+ hake is suggested, manifested as lower condition values in winter, the less productive season. Spatially, better conditioned individuals matched sectors of the gulf where chl‐a concentrations were higher, coupled to the presence of frontal systems. Monitoring age‐0+ hake nutritional status is relevant in the current global change scenario, which might modify phytoplankton biomass and composition and, consequently, the herbivorous zooplankton abundances.Fil: Temperoni, Brenda. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Subsede Instituto Nacional de Investigación y Desarrollo Pesquero; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Massa, Agueda Elena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Subsede Instituto Nacional de Investigación y Desarrollo Pesquero; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Martos, Patricia. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Ciencias Marinas; ArgentinaFil: Marrari, Marina. Ministerio de Defensa. Armada Argentina. Servicio de Hidrografía Naval. Departamento Oceanografía; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Exploring metabolic responses of potato tissue induced by electric pulses

In this study, we investigated the metabolic responses of potato tissue induced by pulsed electric field (PEF). Potato tissue was subjected to field strengths ranging from 30 to 500 V/cm, with a single rectangular pulse of 10 μs, 100 μs, or 1 ms. Metabolic responses were monitored using isothermal calorimetry, changes on electrical resistance during the delivery of the pulse, as well as impedance measurements. Our results show that the metabolic response involves oxygen consuming pathways as well as other unidentified events that are shown to be insensitive to metabolic inhibitors such as KCN and sodium azide. The metabolic response is strongly dependent on pulsing conditions and is independent of the total permeabilization achieved by the pulse. Evidence shows that calorimetry is a simple and powerful method for exploring conditions for metabolic stimulation, providing information on metabolic responses that can not be obtained from electrical measurements. This study set the basis for further investigations on defense-related consequences of PEF-induced stress.Sparbanksstiftelsen Färs & Frosta (Sweden).Fundação para a Ciência e a Tecnologia (FCT).Lund University (Sweden).Department of Cell and Organism Biology; Department of Plant Biochemistry