Neuroelectromagnetic correlates of perceptual closure processes

Perceptual closure refers to the coherent perception of an object under circumstances when the visual information is incomplete. Although the perceptual closure index observed in electroencephalography reflects that an object has been recognized, the full spatiotemporal dynamics of cortical source activity underlying perceptual closure processing remain unknown so far. To address this question, we recorded magnetoencephalographic activity in 15 subjects (11 females) during a visual closure task and performed beamforming over a sequence of successive short time windows to localize high-frequency gamma-band activity (60–100 Hz). Two-tone images of human faces (Mooney faces) were used to examine perceptual closure. Event-related fields exhibited a magnetic closure index between 250 and 325 ms. Time-frequency analyses revealed sustained high-frequency gamma-band activity associated with the processing of Mooney stimuli; closure-related gamma-band activity was observed between 200 and 300 ms over occipitotemporal channels. Time-resolved source reconstruction revealed an early (0–200 ms) coactivation of caudal inferior temporal gyrus (cITG) and regions in posterior parietal cortex (PPC). At the time of perceptual closure (200–400 ms), the activation in cITG extended to the fusiform gyrus, if a face was perceived. Our data provide the first electrophysiological evidence that perceptual closure for Mooney faces starts with an interaction between areas related to processing of three-dimensional structure from shading cues (cITG) and areas associated with the activation of long-term memory templates (PPC). Later, at the moment of perceptual closure, inferior temporal cortex areas specialized for the perceived object are activated, i.e., the fusiform gyrus related to face processing for Mooney stimuli.

Biomechanics on the Half Shell: Functional Performance Influences Patterns of Morphological Variation in the Emydid Turtle carapace

This study uses the carapace of emydid turtles to address hypothesized differences between terrestrial and aquatic species. Geometric morphometrics are used to quantify shell shape, and performance is estimated for two shell functions: shell strength and hydrodynamics. Aquatic turtle shells differ in shape from terrestrial turtle shells and are characterized by lower frontal areas and presumably lower drag. Terrestrial turtle shells are stronger than those of aquatic turtles; many-to-one mapping of morphology to function does not entirely mitigate a functional trade-off between mechanical strength and hydrodynamic performance. Furthermore, areas of morphospace characterized by exceptionally poor performance in either of the functions are not occupied by any emydid species. Though aquatic and terrestrial species show no significant differences in the rate of morphological evolution, aquatic species show a higher lineage density, indicative of a greater amount of convergence in their evolutionary history. The techniques employed in this study, including the modeling of theoretical shapes to assess performance in unoccupied areas of morphospace, suggest a framework for future studies of morphological variation.

La transferencia en la clínica con niños : Continuidades y rupturas

Cada marco teórico recorta una dimensión posible respecto del funcionamiento del aparato psíquico, dando lugar a la puesta en forma de los alcances y los límites, a partir de los cuales se delimitan vías posibles de intervención. En el entramado que allí se constituye, el concepto de transferencia encuentra su asiento. Ahora bien, ¿qué rasgos de particularidad atraviesan las nociones conceptuales cuando se emplazan y articulan con los movimientos fundacionales que dan cuenta de los tiempos de constitución psíquica? Determinar la singularidad de los conceptos, desde su emplazamiento en la red conceptual que cerca los tiempos de la constitución, supone remitirse a los inicios de una práctica. Para ello, se circunscribirán ciertas coordenadas que darán cuenta del trayecto teórico-clínico propuesto por aquellos autores que trazaron el origen de la clínica con niños y adolescentes. La presente investigación se conforma a partir de las propuestas de trabajo dadas en el marco de la carrera de Especialización en Clínica Psicoanalítica con Niños y Adolescentes de la Facultad de Psicología de la UNLP, cuya directora es la profesora psicóloga Norma Najt

La transferencia en la clínica con niños : Continuidades y rupturas

Cada marco teórico recorta una dimensión posible respecto del funcionamiento del aparato psíquico, dando lugar a la puesta en forma de los alcances y los límites, a partir de los cuales se delimitan vías posibles de intervención. En el entramado que allí se constituye, el concepto de transferencia encuentra su asiento. Ahora bien, ¿qué rasgos de particularidad atraviesan las nociones conceptuales cuando se emplazan y articulan con los movimientos fundacionales que dan cuenta de los tiempos de constitución psíquica? Determinar la singularidad de los conceptos, desde su emplazamiento en la red conceptual que cerca los tiempos de la constitución, supone remitirse a los inicios de una práctica. Para ello, se circunscribirán ciertas coordenadas que darán cuenta del trayecto teórico-clínico propuesto por aquellos autores que trazaron el origen de la clínica con niños y adolescentes. La presente investigación se conforma a partir de las propuestas de trabajo dadas en el marco de la carrera de Especialización en Clínica Psicoanalítica con Niños y Adolescentes de la Facultad de Psicología de la UNLP, cuya directora es la profesora psicóloga Norma Najt

La transferencia en la clínica con niños : Continuidades y rupturas

Cada marco teórico recorta una dimensión posible respecto del funcionamiento del aparato psíquico, dando lugar a la puesta en forma de los alcances y los límites, a partir de los cuales se delimitan vías posibles de intervención. En el entramado que allí se constituye, el concepto de transferencia encuentra su asiento. Ahora bien, ¿qué rasgos de particularidad atraviesan las nociones conceptuales cuando se emplazan y articulan con los movimientos fundacionales que dan cuenta de los tiempos de constitución psíquica? Determinar la singularidad de los conceptos, desde su emplazamiento en la red conceptual que cerca los tiempos de la constitución, supone remitirse a los inicios de una práctica. Para ello, se circunscribirán ciertas coordenadas que darán cuenta del trayecto teórico-clínico propuesto por aquellos autores que trazaron el origen de la clínica con niños y adolescentes. La presente investigación se conforma a partir de las propuestas de trabajo dadas en el marco de la carrera de Especialización en Clínica Psicoanalítica con Niños y Adolescentes de la Facultad de Psicología de la UNLP, cuya directora es la profesora psicóloga Norma Najt

Mineralogical, geochemical, and lipid biomarker study of cabonate precipitates at station GeoB9908-1

Carbonate precipitates recovered from 2,000 m water depth at the Dolgovskoy Mound (Shatsky Ridge, north eastern Black Sea) were studied using mineralogical, geochemical and lipid biomarker analyses. The carbonates differ in shape from simple pavements to cavernous structures with thick microbial mats attached to their lower side and within cavities. Low d13C values measured on carbonates (-41 to -32 per mill V-PDB) and extracted lipid biomarkers indicate that anaerobic oxidation of methane (AOM) played a crucial role in precipitating these carbonates. The internal structure of the carbonates is dominated by finely laminated coccolith ooze and homogeneous clay layers, both cemented by micritic high-magnesium calcite (HMC), and pure, botryoidal, yellowish low-magnesium calcite (LMC) grown in direct contact to microbial mats. d18O measurements suggest that the authigenic HMC precipitated in equilibrium with the Black Sea bottom water while the yellowish LMC rims have been growing in slightly 18O-depleted interstitial water. Although precipitated under significantly different environmental conditions, especially with respect to methane availability, all analysed carbonate samples show lipid patterns that are typical for ANME-1 dominated AOM consortia, in the case of the HMC samples with significant contributions of allochthonous components of marine and terrestrial origin, reflecting the hemipelagic nature of the primary sediment.

Multi-textured 3D humanoid reconstruction through passive and active automatic techniques = Reconstrucción de humanoides 3D multi-texturados mediante técnicas pasivas y activas automáticas

The proliferation of video games and other applications of computer graphics in everyday life demands a much easier way to create animatable virtual human characters. Traditionally, this has been the job of highly skilled artists and animators that painstakingly model, rig and animate their avatars, and usually have to tune them for each application and transmission/rendering platform. The emergence of virtual/mixed reality environments also calls for practical and costeffective ways to produce custom models of actual people. The purpose of the present dissertation is bringing 3D human scanning closer to the average user. For this, two different techniques are presented, one passive and one active. The first one is a fully automatic system for generating statically multi-textured avatars of real people captured with several standard cameras. Our system uses a state-of-the-art shape from silhouette technique to retrieve the shape of subject. However, to deal with the lack of detail that is common in the facial region for these kind of techniques, which do not handle concavities correctly, our system proposes an approach to improve the quality of this region. This face enhancement technique uses a generic facial model which is transformed according to the specific facial features of the subject. Moreover, this system features a novel technique for generating view-independent texture atlases computed from the original images. This static multi-texturing system yields a seamless texture atlas calculated by combining the color information from several photos. We suppress the color seams due to image misalignments and irregular lighting conditions that multi-texturing approaches typically suffer from, while minimizing the blurring effect introduced by color blending techniques. The second technique features a system to retrieve a fully animatable 3D model of a human using a commercial depth sensor. Differently to other approaches in the current state of the art, our system does not require the user to be completely still through the scanning process, and neither the depth sensor is moved around the subject to cover all its surface. Instead, the depth sensor remains static and the skeleton tracking information is used to compensate the user’s movements during the scanning stage. RESUMEN La popularización de videojuegos y otras aplicaciones de los gráficos por ordenador en el día a día requiere una manera más sencilla de crear modelos virtuales humanos animables. Tradicionalmente, estos modelos han sido creados por artistas profesionales que cuidadosamente los modelan y animan, y que tienen que adaptar específicamente para cada aplicación y plataforma de transmisión o visualización. La aparición de los entornos de realidad virtual/mixta aumenta incluso más la demanda de técnicas prácticas y baratas para producir modelos 3D representando personas reales. El objetivo de esta tesis es acercar el escaneo de humanos en 3D al usuario medio. Para ello, se presentan dos técnicas diferentes, una pasiva y una activa. La primera es un sistema automático para generar avatares multi-texturizados de personas reales mediante una serie de cámaras comunes. Nuestro sistema usa técnicas del estado del arte basadas en shape from silhouette para extraer la forma del sujeto a escanear. Sin embargo, este tipo de técnicas no gestiona las concavidades correctamente, por lo que nuestro sistema propone una manera de incrementar la calidad en una región del modelo que se ve especialmente afectada: la cara. Esta técnica de mejora facial usa un modelo 3D genérico de una cara y lo modifica según los rasgos faciales específicos del sujeto. Además, el sistema incluye una novedosa técnica para generar un atlas de textura a partir de las imágenes capturadas. Este sistema de multi-texturización consigue un atlas de textura sin transiciones abruptas de color gracias a su manera de mezclar la información de color de varias imágenes sobre cada triángulo. Todas las costuras y discontinuidades de color debidas a las condiciones de iluminación irregulares son eliminadas, minimizando el efecto de desenfoque de la interpolación que normalmente introducen este tipo de métodos. La segunda técnica presenta un sistema para conseguir un modelo humano 3D completamente animable utilizando un sensor de profundidad. A diferencia de otros métodos del estado de arte, nuestro sistema no requiere que el usuario esté completamente quieto durante el proceso de escaneado, ni mover el sensor alrededor del sujeto para cubrir toda su superficie. Por el contrario, el sensor se mantiene estático y el esqueleto virtual de la persona, que se va siguiendo durante el proceso, se utiliza para compensar sus movimientos durante el escaneado.

Non-normally distributed data and non-parametric statistics

Different types of numerical data can be collected in a scientific investigation and the choice of statistical analysis will often depend on the distribution of the data. A basic distinction between variables is whether they are ‘parametric’ or ‘non-parametric’. When a variable is parametric, the data come from a symmetrically shaped distribution known as the ‘Gaussian’ or ‘normal distribution’ whereas non-parametric variables may have a distribution which deviates markedly in shape from normal. This article describes several aspects of the problem of non-normality including: (1) how to test for two common types of deviation from a normal distribution, viz., ‘skew’ and ‘kurtosis’, (2) how to fit the normal distribution to a sample of data, (3) the transformation of non-normally distributed data and scores, and (4) commonly used ‘non-parametric’ statistics which can be used in a variety of circumstances.

Entre cartas e contos na sala de aula: diálogos e afetos em textos de Mário de Andrade e Câmara Cascudo

Specific educational material production for a group of level IV – 8th and 9th years of Youth and Adults Education, having as starting point the reading of a series of letter of correspondence between Câmara Cascudo and Mário de Andrade in the 1920s, and the verification of the way the dialog between the two authors reveals elements that transpire themselves in the tale entitled “Piá não sofre? Sofre”, from the book Os contos de Belazarte, de Mário de Andrade. The educational material production was preceded by the analysis of the selected tale, which will be studied along with some of the letters, in an analysis of the textual, discursive and semantic features of the text in representation of these both genres: letter and tale. The selected tale was written between 1923 and 1926, dates close to the years when the author came by Rio Grande do Norte state, in the years from 1927 to 1929, accompanied by Câmara Cascudo, being also this period that there are records of letters in the set of correspondence between them. To the reading of the selected material, it was used theoretical references from literature and literary historiography, especially the history of Brazilian modernist movement. To the production of the educational material, it was chosen as theoretical reference the accumulated knowledge in the area of literature teaching, literacy and the recommendations of the Brazilian National Curriculum Parameters. The methodology in this study was constructed from the theoretical references and had as basic support the study of didactic sequences from which a specific thematic unit got its shape from, required by the analyzed material and tested in a classroom.

Entre cartas e contos na sala de aula: diálogos e afetos em textos de Mário de Andrade e Câmara Cascudo

Specific educational material production for a group of level IV – 8th and 9th years of Youth and Adults Education, having as starting point the reading of a series of letter of correspondence between Câmara Cascudo and Mário de Andrade in the 1920s, and the verification of the way the dialog between the two authors reveals elements that transpire themselves in the tale entitled “Piá não sofre? Sofre”, from the book Os contos de Belazarte, de Mário de Andrade. The educational material production was preceded by the analysis of the selected tale, which will be studied along with some of the letters, in an analysis of the textual, discursive and semantic features of the text in representation of these both genres: letter and tale. The selected tale was written between 1923 and 1926, dates close to the years when the author came by Rio Grande do Norte state, in the years from 1927 to 1929, accompanied by Câmara Cascudo, being also this period that there are records of letters in the set of correspondence between them. To the reading of the selected material, it was used theoretical references from literature and literary historiography, especially the history of Brazilian modernist movement. To the production of the educational material, it was chosen as theoretical reference the accumulated knowledge in the area of literature teaching, literacy and the recommendations of the Brazilian National Curriculum Parameters. The methodology in this study was constructed from the theoretical references and had as basic support the study of didactic sequences from which a specific thematic unit got its shape from, required by the analyzed material and tested in a classroom.

STRUCTURAL ANALYSIS OF RIBOSOME BINDING ELEMENTS OF THE 3´ UTR IN TWO POSITIVE-STRAND PLANT RNA VIRUSES

Turnip crinkle virus (TCV) and Pea enation mosaic virus (PEMV) are two positive (+)-strand RNA viruses that are used to investigate the regulation of translation and replication due to their small size and simple genomes. Both viruses contain cap-independent translation elements (CITEs) within their 3´ untranslated regions (UTRs) that fold into tRNA-shaped structures (TSS) according to nuclear magnetic resonance and small angle x-ray scattering analysis (TCV) and computational prediction (PEMV). Specifically, the TCV TSS can directly associate with ribosomes and participates in RNA-dependent RNA polymerase (RdRp) binding. The PEMV kissing-loop TSS (kl-TSS) can simultaneously bind to ribosomes and associate with the 5´ UTR of the viral genome. Mutational analysis and chemical structure probing methods provide great insight into the function and secondary structure of the two 3´ CITEs. However, lack of 3-D structural information has limited our understanding of their functional dynamics. Here, I report the folding dynamics for the TCV TSS using optical tweezers (OT), a single molecule technique. My study of the unfolding/folding pathways for the TCV TSS has provided an unexpected unfolding pathway, confirmed the presence of Ψ3 and hairpin elements, and suggested an interconnection between the hairpins and pseudoknots. In addition, this study has demonstrated the importance of the adjacent upstream adenylate-rich sequence for the formation of H4a/Ψ3 along with the contribution of magnesium to the stability of the TCV TSS. In my second project, I report on the structural analysis of the PEMV kl-TSS using NMR and SAXS. This study has re-confirmed the base-pair pattern for the PEMV kl-TSS and the proposed interaction of the PEMV kl-TSS with its interacting partner, hairpin 5H2. The molecular envelope of the kl-TSS built from SAXS analysis suggests the kl-TSS has two functional conformations, one of which has a different shape from the previously predicted tRNA-shaped form. Along with applying biophysical methods to study the structural folding dynamics of RNAs, I have also developed a technique that improves the production of large quantities of recombinant RNAs in vivo for NMR study. In this project, I report using the wild-type and mutant E.coli strains to produce cost-effective, site-specific labeled, recombinant RNAs. This technique was validated with four representative RNAs of different sizes and complexity to produce milligram amounts of RNAs. The benefit of using site-specific labeled RNAs made from E.coli was demonstrated with several NMR techniques.

Shape discrimination using invariants defined from higher-order spectra

An approach to pattern recognition using invariant parameters based on higher-order spectra is presented. In particular, bispectral invariants are used to classify one-dimensional shapes. The bispectrum, which is translation invariant, is integrated along straight lines passing through the origin in bifrequency space. The phase of the integrated bispectrum is shown to be scale- and amplification-invariant. A minimal set of these invariants is selected as the feature vector for pattern classification. Pattern recognition using higher-order spectral invariants is fast, suited for parallel implementation, and works for signals corrupted by Gaussian noise. The classification technique is shown to distinguish two similar but different bolts given their one-dimensional profiles

Looming aircraft threats : shape-based passive ranging of aircraft from monocular vision

This paper proposes new techniques for aircraft shape estimation, passive ranging, and shape-adaptive hidden Markov model filtering which are suitable for a monocular vision-based non-cooperative collision avoidance system. Vision-based passive ranging is an important missing technology that could play a significant role in resolving the sense-and-avoid problem in un-manned aerial vehicles (UAVs); a barrier hindering the wider adoption of UAVs for civilian applications. The feasibility of the pro- posed shape estimation, passive ranging and shape-adaptive filtering techniques is evaluated on flight test data.