Anelastic dynamo models with variable electrical conductivity: an application to gas giants

The observed surface dynamics of Jupiter and Saturn is dominated by a banded system of zonal winds. Their depth remains unclear but they are thought to be confined to the very outer envelopes where hydrogen remains molecular and the electrical conductivity is small. The dynamo maintaining the dipole-dominated magnetic fields of both gas giants likely operates in the deeper interior where hydrogen assumes a metallic state. Here, we present numerical simulations that attempt to model both the zonal winds and the interior dynamo action in an integrated approach. Using the anelastic version of the MHD code MagIC, we explore the effects of density stratification and radial electrical conductivity variation. The electrical conductivity is mostly assumed to remain constant in the thicker inner metallic region and it decays exponentially towards the outer boundary throughout the molecular envelope. Our results show that the combination of stronger density stratification and weaker conducting outer layer is essential for reconciling dipole dominated dynamo action and a fierce equatorial zonal jet. Previous simulations with homogeneous electrical conductivity show that both are merely exclusive, with solutions either having strong zonal winds and multipolar magnetic fields or weak zonal winds and dipole-dominated magnetic fields. All jets tend to be geostrophic and therefore reach right through the convective shell in our simulations. The particular setup explored here allows a strong equatorial jet to remain confined to the weaker conducting outer region where it does not interfere with the deeper seated dynamo action. The flanking mid to high latitude jets, on the other hand, have to remain faint to yield a strongly dipolar magnetic field. The fiercer jets on Jupiter and Saturn only seem compatible with the observed dipolar fields when they remain confined to a weaker conducting outer layer.Comment: 16 pages, 11 figures, 2 tables, submitted to PEP

Essential tremor: clinical observations

The authors have studied 53 patients with essential tremor, focusing its clinical and epidemiological aspects. There were familial history in 37.70% of all cases, prevailing in females (56.60%) and white people (69.80%); nevertheless this difference can not be assured from the statistical point of view due to lack of population data. We agreed that the main incidence of this syndrome occurred beyond the 5th decade, specially during the 6th and 7th decades. Topographically, we could observe that the hand tremor predominated, with an incidence of 96.20% of the total number of cases, followed by head tremor (28.30%), voice tremor (16.99%), leg tremor (11.30%), tongue tremor (3.78%) and trunk tremor (1.88%). These focal tremors were seldom observed alone and we noted frequent association with hand tremor.Foram analisados 53 casos de tremor essencial (TE) do Ambulatório de Distúrbios do Movimento da Disciplina de Neurologia do Hospital Universitário Pedro Ernesto - UERJ, quanto a história familiar, sexo, idade e áreas de acometimento corporal. Dos pacientes avaliados, somente 37,70% apresentavam história familiar para TE. Observa-se predomínio do sexo feminino (56,60%) em relação ao masculino (43,40%) e da raça branca (69,80%) sobre as demais, entretanto, não se pode afirmar que esta diferença seja estatisticamente significativa, por não se dispor de dados populacionais. Nossos achados mostraram maior incidência após os 50 anos de idade, predominando nas 6ª e 7ª décadas, principalmente nesta última. O acometimento das mãos (96,20%) prevaleceu sobre as demais áreas corporais: cefálico (28,30%), de voz (16,99%), de pernas (11,30%), de língua (3,78%) e de tronco (1,88%). Estes dificilmente se apresentavam isolados e ocorriam, em sua maioria, associados ao tremor de mãos.EPMUniversidade do Estado do Rio de Janeiro Hospital Universitário Pedro Ernesto Ambulatório de Distúrbios do MovimentoUNIFESP, EPMSciEL

A PAISAGEM EM ALEXANDER VON HUMBOLDT: O MODO DESCRITIVO DOS QUADROS DA NATUREZA

A PAISAGEM EM ALEXANDER VON HUMBOLDT: O MODO DESCRITIVO DOS QUADROS DA NATUREZ

Consistent scaling laws in anelastic spherical shell dynamos

Numerical dynamo models always employ parameter values that differ by orders of magnitude from the values expected in natural objects. However, such models have been successful in qualitatively reproducing properties of planetary and stellar dynamos. This qualitative agreement fuels the idea that both numerical models and astrophysical objects may operate in the same asymptotic regime of dynamics. This can be tested by exploring the scaling behavior of the models. For convection-driven incompressible spherical shell dynamos with constant material properties, scaling laws had been established previously that relate flow velocity and magnetic field strength to the available power. Here we analyze 273 direct numerical simulations using the anelastic approximation, involving also cases with radius-dependent magnetic, thermal and viscous diffusivities. These better represent conditions in gas giant planets and low-mass stars compared to Boussinesq models. Our study provides strong support for the hypothesis that both mean velocity and mean magnetic field strength scale as a function of power generated by buoyancy forces in the same way for a wide range of conditions.Comment: 9 pages, 4 figures, 1 table; data used in the paper can be found in "Dataset.txt" file available in the source; to appear in Ap

Desarrollo de un software en MATLAB para la simulación de campo ultrasónico

The study of the acoustic field generated by an ultrasonic transducer is fundamental to its construction and characterization, because it defines how it will behave before being built. It also defines whether it is feasible or not, for the application to which it was designed. It can also lead to modifications to the project so it behaves as expected. In this work, a software was implemented in MATLAB®, for computational simulation of acoustic fields generated by ultrasonic transducers of different configurations. Two models were used, Zemanek and Stepanishen. Transducers with focus and apodization and transmission medium with attenuation may also be simulated. For the simulation of Zemanek’s model, the mathematical method of discretization was used. The Stepanishen’s model used an analytical solution for the impulse response. The developed programs were aggregated into a computer package, named FSIM, and a graphic interface was created. The user can choose among some of the transducer configurations and simulation parameters already implemented. FSIM has a modular architecture and allows further simulation modules to be added. The simulations were validated comparing results to those previously published in classical papers from Zemanek, and from Lockwood and Willete, in addition to prior results from research studies conducted at the Biomedical Engineering Department of the School of Electrical and Computing Engineering at the Universidade Estadual de Campinas (UNICAMP).El estudio del campo acústico generado por un transductor ultrasónico es fundamental para su construcción y caracterización, ya que define cómo se comportará antes de ser construido. También define si realmente es factible para la aplicación a la que fue diseñado, y también puede sugerir modificaciones al proyecto, para que se comporte como se espera. En este trabajo un software fue implementado en MATLAB®, para la simulación computacional de los campos acústicos generados por los transductores ultrasónicos de diferentes configuraciones. Dos modelos fueran usados, Zemanek y Stepanishen. Transductores con el enfoque y apodización y medios con atenuación también pueden ser simulados. Para la simulación del modelo de Zemanek, se utilizó el método matemático de discretización y para el modelo de Stepanishen, se empleó una solución analítica para la respuesta impulsiva. Los programas desarrollados fueron agregados en un paquete computacional, llamado FSIM, y una interfaz gráfica fue creada. El usuario puede elegir entre algunas configuraciones del transductor y parámetros de simulación ya implementados; FSIM tiene una arquitectura modular y permite que otros módulos de simulación sean añadidos. Las simulaciones fueron validadas comparando resultados obtenidos previamente por otros trabajos de investigación del Departamento de Ingeniería Biomédica de la Facultad de Ingeniería Eléctrica y Computación de la UNICAMP y por los artículos clásicos de Zemanek y Lockwood y Willette

The development of upright face perception depends on evolved orientation-specific mechanisms and experience

Here we examine whether our impressive ability to perceive upright faces arises from evolved orientation-specific mechanisms, our extensive experience with upright faces, or both factors. To do so, we tested Claudio, a man with a congenital joint disorder causing his head to be rotated back so that it is positioned between his shoulder blades. As a result, Claudio has seen more faces reversed in orientation to his own face than matched to it. Controls exhibited large inversion effects on all tasks, but Claudio performed similarly with upright and inverted faces in both detection and identity-matching tasks, indicating these abilities are the product of evolved mechanisms and experience. In contrast, he showed clear upright superiority when detecting “Thatcherized” faces (faces with vertically flipped features), suggesting experience plays a greater role in this judgment. Together, these findings indicate that both evolved orientation-specific mechanisms and experience contribute to our proficiency with upright faces

Antigen, antibody and immune complex detection in serum samples from rats experimentally infected with Strongyloides venezuelensis

AbstractIn order to establish an antigen, antibody and immune complex detection by enzyme-linked immunosorbent assay (ELISA) in serum samples, normal or immunocompromised Wistar rats experimentally infected with Strongyloides venezuelensis were used. The microtitre plates were coated with IgG anti-S. venezuelensis for antigen and immune complex detection and with alkaline parasite extract for antibody detection. Analysis revealed at least 12.5μg/mL of S. venezuelensis specific antigens in serum samples. Assay for antigen detection was not a good approach for evaluating infection in normal or immunocompromised rats. In normal rats IgG specific for S. venezuelensis was preferentially detected during the first 13days post-infection (p.i.) and immune complex detection was significantly reduced in 21 p.i. day. On the other hand, in immunocompromised rats, IgG and immune complex were detected during the entire kinetic (5, 8, 13 and 21 p.i). These results suggest that immune complex screening seems to be an alternative for early strongyloidiasis diagnosis in immunocompromised individuals

Surface modification of banana-based lignocellulose fibres

Lignocellulosic raw materials were isolated from rachis of Musa acuminata Colla var. cavendish and characterised before and after chemical modification. The rachis was submitted to different mechanical treatments, milling and defibration, resulting in rachis powder and rachis fi bers, respectively. The chemical composition of these two samples was established and it was shown that rachis fibres exhibited higher polysaccharide and lignin contents and lower amounts of ash and extractives components, as compared with the rachis powder. The effects of solvent extrac tion, alkali treatment and chemical modification using phenyl isocyanate, maleic anhydride, alkenyl succinic anhydride and alkyl ketone dimer as grafting agents were studied. The materials were characterized in terms of chemical structure by ATR–FT-IR and 13C-CP-MAS-NMR spectroscopy, morphology by scanning electron microscopy and surface energies by inverse gas chromatography and contact angle measurements. The surface energy of these materials was found to be very close to other similar lignocellulosic materials. Finally, the water absorption of these materials before and after treatment was ascertained. The modified fibres showed considerable changes in ATR–FT-IR and 13C-CP-MAS-NMR spectra and surface properties, providing very convincing evidence that chemical grafting had occurred.info:eu-repo/semantics/publishedVersio

Short-term alterations in hippocampal glutamate transport system caused by one-single neonatal seizure episode: Implications on behavioral performance in adulthood

AbstractImpairment in the activity and expression of glutamate transporters has been found in experimental models of epilepsy in adult animals. However, there are few studies investigating alterations on glutamate transporters caused by epilepsy in newborn animals, especially in the early periods after seizures. In this study, alterations in the hippocampal glutamate transporters activity and immunocontent were investigated in neonatal rats (7 days old) submitted to kainate-induced seizures model. Glutamate uptake, glutamate transporters (GLT-1, GLAST, EAAC1) and glutamine synthetase (GS) were assessed in hippocampal slices obtained 12h, 24h, 48h, 72h and 60 days after seizures. Immunoreactivity for hippocampal GFAP, NeuN and DAPI were assessed 24h after seizure. Behavioral analysis (elevated-plus maze and inhibitory avoidance task) was also investigated in the adult animals (60 days old). The decrease on glutamate uptake was observed in hippocampal slices obtained 24h after seizures. The immunocontent of GLT-1 increased at 12h and decreased at 24h (+62% and −20%, respectively), while GLAST increased up to 48h after seizures. No alterations were observed for EAAC1 and GS. It should be mentioned that there were no long-term changes in tested glutamate transporters at 60 days after kainate treatment. GFAP immunoreactivity increased in all hippocampal subfields (CA1, CA3 and dentate gyrus) with no alterations in NeuN and DAPI staining. In the adulthood, kainate-treated rats showed anxiety-related behavior and lower performance in the inhibitory avoidance task. Our findings indicate that acute modifications on hippocampal glutamate transporters triggered by a single convulsive event in early life may play a role in the behavioral alterations observed in adulthood

Structural characterization of lignin from leaf sheaths of “dwarf cavendish” banana plant

Dioxane lignin (DL) isolated from leaf sheaths of banana plant (Musa acuminata Colla var. cavendish) and in situ lignin were submitted to a comprehensive structural characterization employing spectroscopic (UV, FTIR, solid state 13C CP-MAS NMR, liquid state 13C and 1H NMR) and chemical degradation techniques (permanganate and nitrobenzene oxidation). Results obtained showed that banana plant leaf sheath lignin is of HGS type with a molar proportion of p-hydroxyphenyl (H)/guaiacyl (G)/syringyl (S) units of 12:25:63. Most of the H units in DL are terminal phenolic coumarates linked to other lignin substructures by benzyl and Cgamma-ester bonds in contrast to ferulates that are mainly ether linked to bulk lignin. It is proposed that banana plant leaf sheath lignin is chemically bonded to suberin-like components of cell tissues by ester linkages via essentially hydroxycinnamic acid residues. beta-O-4 structures (0.31/C6), the most abundant in DL, comprise mainly S units, whereas a significant proportion of G units is bonded by beta-5, 5-5', and 4-O-5' linkages contributing to ca. 80% of condensed structures in DL.info:eu-repo/semantics/publishedVersio