Three-Body Dynamics and Self-Powering of an Electrodynamic Tether in a Plasmasphere

The dynamics of an electrodynamic tether in a three-body gravitational environment are investigated. In the classical two-body scenario the extraction of power is at the expense of orbital kinetic energy. As a result of power extraction, an electrodynamic tether satellite system loses altitude and deorbits. This concept has been proposed and well investigated in the past, for example for orbital debris mitigation and spent stages reentry. On the other hand, in the three-body scenario an electrodynamic tether can be placed in an equilibrium position fixed with respect to the two primary bodies without deorbiting, and at the same time generate power for onboard use. The appearance of new equilibrium positions in the perturbed three-body problem allow this to happen as the electrical power is extracted at the expenses of the plasma corotating with the primary body. Fundamental differences between the classical twobody dynamics and the new phenomena appearing in the circular restricted three-body problem perturbed by the electrodynamic force of the electrodynamic tether are shown in the paper. An interesting application of an electrodynamic tether placed in the Jupiter plasma torus is then considered, in which the electrodynamic tether generates useful electrical power of about 1 kW with a 20-km-long electrodynamic tether from the environmental plasma without losing orbital energy

Variability in disease phenotypes within a single PRNP genotype suggests the existence of multiple natural sheep scarpie strains within Europe

Variability of pathological phenotypes within classical sheep scrapie cases has been reported for some time, but in many instances it has been attributed to differences in the PRNP genotype of the host. To address this issue we have examined by immunohistochemistry (IHC) and Western blotting (WB) for the disease-associated form of the prion protein (PrPd), the brains of 23 sheep from five European countries, all of which were of the same ARQ/ARQ genotype. As a result of IHC examinations, sheep were distributed into five groups with different phenotypes and the groups were the same regardless of the scoring method used, ‘long’ or ‘short’ PrPd profiling. The groups made did not respond to the geographical origin of the cases and did not correlate with the vacuolar lesion profiles, which showed a high individual variability. Discriminatory IHC and WB methods coincided to detect a ‘CH1641-like’ case but otherwise correlated poorly in the classification of disease phenotypes. No other polymorphisms of the PRNP gene were found that could account for the pathological differences, except perhaps for a sheep from Spain with a mutation at codon 103 and a unique pathological phenotype. Preliminary evidence indicates that those different IHC phenotypes correlate with distinct biological properties on bioassay, suggesting that they are indicative of strain diversity. We therefore conclude that natural scrapie strains exist and that they can be revealed by detailed pathological examinations, which can be harmonized between laboratories to produce comparable results

Seeding approach to bubble nucleation in superheated Lennard-Jones fluids

We investigate vapor homogeneous nucleation in a superheated Lennard-Jones liquid with computer simulations. Special simulation techniques are required to address this study since the nucleation of a critical vapor bubble-one that has an equal chance to grow or shrink-in a moderately superheated liquid is a rare event. We use the Seeding method, which combines Classical Nucleation Theory with computer simulations of a liquid containing a vapor bubble to provide bubble nucleation rates in a wide temperature range. Seeding has been successfully applied to investigate the nucleation of crystals in supercooled fluids, and here we apply it to the liquid-to-vapor transition. We find that the Seeding method provides nucleation rates that are consistent with independent calculations not based on the assumptions of Classical Nucleation Theory. Different criteria to determine the radius of the critical bubble give different rate values. The accuracy of each criterion depends of the degree of superheating. Moreover, seeding simulations show that the surface tension depends on pressure for a given temperature. Therefore, using Classical Nucleation Theory with the coexistence surface tension does not provide good estimates of the nucleation rate

Toxicological Study Employing Repeated Doses of Garcinielliptone FC, a Polyisoprenylated-Benzophenone Isolated from Seed of Platonia Insignis Mart

The major constituent from the hexane extract of the seeds of P. insignis is GFC (garcinielliptone FC). Doses of 25, 50and 75 mg/kg of GFC were aseptically suspended in 0.05% Tween 80 dissolved in 0.9% saline (vehicle) and orally administered for30, 90 and 120 consecutive days to adult Swiss mice. In this work, the repeated oral administration, in animals of both sexes,demonstrates that this compound is not able to induce mortality and/or behavioral changes in adult mice. In addition, body weightgain, feed intake and disposal of excreta were not altered by the administration of this compound with repeated doses. Furthermore,no differences in weight and macroscopic structure of the brain, liver, kidney, lung, heart and spleen between groups of male andfemale adult mice were observed after treatment. During the periods of treatment, GFC produced no significant changes onhaematological and biochemical parameters in male and female mice treated with all doses used. The aim of this study was toinvestigate the toxicological potential of GFC through behavioral, hematological, biochemical and morphological parameters inanimals in order to ensure the safe use of Platonia insignis in folk medicine.Fil: Silva, Ana P.. Federal University of Piauí; BrasilFil: Filho, José Carlos C. L. S.. North Union of Parana; BrasilFil: da Costa Júnior, Joaquim S.. Federal Institute of Piauí; BrasilFil: Peláez, Walter José. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; ArgentinaFil: Faillace, Martín Sebastián. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; ArgentinaFil: Falcão Ferraz, Alexandre de B.. Lutheran University of Brazil; BrasilFil: David, Jorge M.. Institute Of Chemistry, Federal University Of Bahia; Brasil. Universidade Federal da Bahia; BrasilFil: Freitas, Rivelilson M.. Federal University of Bahia; Brasi

Morphological variation of Astyanax species, subgenus Zygogaster (Teleostei, Characidae)

Astyanax es un género diverso de peces neotropicales, cuyas especies habitan gran variedad de ambientes acuáticos. La situación taxonómica de los subgéneros y de sus especies, no difiere de la problemática que presenta el género Astyanax. Basándonos en 354 individuos, se analizó la variación morfológica de cuatro especies del subgénero Zygogaster (A. atratoensis, A. caucanus, A. filiferus y A. magdalenae) mediante un análisis morfogeométrico comparado con dos especies del grupo hermano Poecilurichthys (A. orthodus y A. superbus). El ACP (Análisis de Componentes Principales) y AVC (Análisis de Variables Canónicas) evidenciaron afinidad morfológica entre los subgéneros e indicaron varianza en la profundidad del cuerpo, tendencia anterior del origen de la aleta dorsal y mancha humeral, depresión sobre la superficie dorsal del cráneo, y desplazamiento ventral de la orbita y el hocico. La variación entre las especies indicó aislamiento del tercer infraorbital del preopérculo y protrusión del extremo ventral del maxilar. La variación en estas estructuras evidencia especiación adaptativa como posible alternativa a la especiación por aislamiento geográfico. Palabras clave: Astyanax, Characido, Morfogeometría, Disparidad, Colombia.Astyanax es un género diverso de peces neotropicales, cuyas especies habitan gran variedad de ambientes acuáticos. La situación taxonómica de los subgéneros y de sus especies, no difiere de la problemática que presenta el género Astyanax. Basándonos en 354 individuos, se analizó la variación morfológica de cuatro especies del subgénero Zygogaster (A. atratoensis, A. caucanus, A. filiferus y A. magdalenae) mediante un análisis morfogeométrico comparado con dos especies del grupo hermano Poecilurichthys (A. orthodus y A. superbus). El ACP (Análisis de Componentes Principales) y AVC (Análisis de Variables Canónicas) evidenciaron afinidad morfológica entre los subgéneros e indicaron varianza en la profundidad del cuerpo, tendencia anterior del origen de la aleta dorsal y mancha humeral, depresión sobre la superficie dorsal del cráneo, y desplazamiento ventral de la orbita y el hocico. La variación entre las especies indicó aislamiento del tercer infraorbital del preopérculo y protrusión del extremo ventral del maxilar. La variación en estas estructuras evidencia especiación adaptativa como posible alternativa a la especiación por aislamiento geográfico. Palabras clave: Astyanax, Characido, Morfogeometría, Disparidad, Colombia.The diverse Neotropical fish genus Astyanax inhabits a variety of aquatic environments. As with other species in this genus, the taxonomic status and phylogenetic relationships of species of this subgenus remain largely undetermined. Based on 354 individuals, we analyzed the morphological variation of four species of the subgenus Zygogaster (A. atratoensis, A. caucanus, A. filiferus, and A. magdalenae) using procrustes analysis and compared findings with two species of the sister group: subgenus Poecilurichthys (A. orthodus y A. superbus). The PCA (Principal Component Analysis) and CVA (Canonical Variates Analysis) showed morphological affinity between the subgenera and indicated variance in body depth, anterior trend of dorsal fin origin and humeral spot, depression on the dorsal surface of the skull, and ventral displacement of the orbit and snout. The variation in these structures may provide evidence supporting adaptive speciation as an alternative to speciation driven by geographical isolation. Key words: Astyanax, Characid fish, Morphogeometry, Disparity, Colombia

Variación morfológica de las especies de Astyanax, subgénero Zygogaster (Teleostei, Characidae)

Morphological variation of Astyanax species, subgenus Zygogaster (Teleostei, Characidae) The diverse Neotropical fish genus Astyanax inhabits a variety of aquatic environments. As with other species in this genus, the taxonomic status and phylogenetic relationships of species of this subgenus remain largely undetermined. Based on 354 individuals, we analyzed the morphological variation of four species of the subgenus Zygogaster (A. atratoensis, A. caucanus, A. filiferus, and A. magdalenae) using procrustes analysis and compared findings with two species of the sister group: subgenus Poecilurichthys (A. orthodus and A. superbus). The PCA (Principal Component Analysis) and CVA (Canonical Variates Analysis) showed morphological affinity between the subgenera and indicated variance in body depth, anterior trend of dorsal fin origin and humeral spot, depression on the dorsal surface of the skull, and ventral displacement of the orbit and snout. The variation in these structures may provide evidence supporting adaptive speciation as an alternative to speciation driven by geographical isolation

Photocatalytic degradation of contaminants of concern with composite NF-TiO2 films under visible and solar light

This study reports the synthesis and characterization of composite nitrogen and fluorine co-doped titanium dioxide (NF-TiO2) for the removal of contaminants of concern (COCs) in wastewater under visible and solar light. Monodisperse anatase TiO2 nanoparticles of different sizes and Evonik P25 were assembled to immobilized NF-TiO2 by direct incorporation into the sol-gel or by the layer-by-layer technique. The composite films were characterized with X-ray diffraction, high resolution-transmission electron microscopy, environmental scanning electron microscopy, and porosimetry analysis. The photocatalytic degradation of atrazine, carbamazepine, and caffeine was evaluated in a synthetic water solution and in an effluent from a hybrid biological concentrator reactor (BCR). Minor aggregation and improved distribution of monodisperse titania particles was obtained with NF-TiO2-monodisperse (10 and 50 nm) from the layer-by-layer technique than with NF-TiO2 + monodisperse TiO2 (300 nm) directly incorporated into the sol. The photocatalysts synthesized with the layer-by-layer method achieved significantly higher degradation rates in contrast with NF-TiO2-monodisperse titania (300 nm) and slightly faster values when compared with NF-TiO2-P25. Using NF-TiO2 layer-by-layer with monodisperse TiO2 (50 nm) under the solar light irradiation, the respective degradation rates in synthetic water and BCR effluent were 14.6 and 9.5·10-3 min-1 for caffeine, 12.5 and 9.0·10-3 min-1 for carbamazepine, and 10.9 and 5.8·10-3 min-1 for atrazine. These results suggest that the layer-by-layer technique is a promising method for the synthesis of composite TiO2-based films compared to the direct addition of nanoparticles into the sol