Highly structured slow solar wind emerging from an equatorial coronal hole.

During the solar minimum, when the Sun is at its least active, the solar wind1,2 is observed at high latitudes as a predominantly fast (more than 500 kilometres per second), highly Alfvénic rarefied stream of plasma originating from deep within coronal holes. Closer to the ecliptic plane, the solar wind is interspersed with a more variable slow wind3 of less than 500 kilometres per second. The precise origins of the slow wind streams are less certain4; theories and observations suggest that they may originate at the tips of helmet streamers5,6, from interchange reconnection near coronal hole boundaries7,8, or within coronal holes with highly diverging magnetic fields9,10. The heating mechanism required to drive the solar wind is also unresolved, although candidate mechanisms include Alfvén-wave turbulence11,12, heating by reconnection in nanoflares13, ion cyclotron wave heating14 and acceleration by thermal gradients1. At a distance of one astronomical unit, the wind is mixed and evolved, and therefore much of the diagnostic structure of these sources and processes has been lost. Here we present observations from the Parker Solar Probe15 at 36 to 54 solar radii that show evidence of slow Alfvénic solar wind emerging from a small equatorial coronal hole. The measured magnetic field exhibits patches of large, intermittent reversals that are associated with jets of plasma and enhanced Poynting flux and that are interspersed in a smoother and less turbulent flow with a near-radial magnetic field. Furthermore, plasma-wave measurements suggest the existence of electron and ion velocity-space micro-instabilities10,16 that are associated with plasma heating and thermalization processes. Our measurements suggest that there is an impulsive mechanism associated with solar-wind energization and that micro-instabilities play a part in heating, and we provide evidence that low-latitude coronal holes are a key source of the slow solar wind.

Use of autologous tooth-derived material as a graft in the post-extraction socket. Split-mouth study with radiological and histological analysis.

BACKGROUND: The healing process after tooth removal involves bone remodelling which implies some loss of alveolar bone volume. Among materials proposed for minimising this remodelling and preserving the bone, autologous dental tissue is a promising option, but more data are needed. In this context, we evaluated size and density changes using cone beam computed tomography in autologous dental material (ADM)-preserved sockets compared to controls, and assessed biological responses by histological analysis. METHODS: A split-mouth study was conducted including 22 patients, who underwent removal of ≥ 2 single-rooted teeth with intact sockets, assigning one socket to the experimental group which received ADM for alveolar preservation and another to the control group, which only underwent blood clot stabilisation. Cone beam computed tomography was performed postoperatively (week 0) and at weeks 8 and 16 to assess socket size and bone density. Histological analysis was carried out on trephine biopsies taken (Ø4 × 4.5 mm) from the experimental group. RESULTS: Less horizontal shrinkage was observed in the ADM group, especially at week 16 considering the group-by-time interaction for the following variables: difference in height between the lingual and buccal alveolar crests (-1.00; p < .01; 95% CI: -0.28 - -1.73), and half-widths, measured as the distance from the long axis of the missing tooth to the buccal alveolar crest at 1 mm (-0.61; p < .01; 95% CI: -0.18 - -1.04) and at 3 mm (-0.56; p < .01; 95% CI: -0.15 - -0.97) below the crest, with mean decreases of 1.07 and 2.14 mm in height difference, 0.66 and 1.32 mm in half-width at 1 mm and 0.43 and 1.02 mm in half-width at 3 mm in ADM and control groups respectively. Densitometry analysis showed higher bone densities in Hounsfield units in the ADM group considering all factors analysed regardless of time point and socket third (coronal, middle, or apical). Histologically, there were no signs of inflammation or foreign body reaction, and dentin particles were surrounded by and in close contact with bone tissue. CONCLUSION: These results add to the evidence that dentin can be used successfully as a material for alveolar socket preservation, given its desirable mechanical and biological properties, and warrant larger studies.

3D solid of SARS-CoV-2 viral particles applying Legendre polynomials from tomography Fourier analysis.

We show the construction of 3D solids (volumetric 3D models) of SARS-CoV-2 viral particles from the tomographic studies (videos) of SARS-CoV-2-infected tissues. To this aim, we propose a video analysis (tomographic images) by frames (medical images of the virus), which we set as our metadata. We optimize the frames by means of Fourier analysis, which induces a periodicity with simple structure patterns to minimize noise filtering and to obtain an optimal phase of the objects in the image, focusing on the SARS-CoV-2 cells to obtain a medical image under study phase (MIS) (process repeated over all frames). We build a Python algorithm based on Legendre polynomials called "2DLegendre_Fit," which generates (using multilinear interpolation) intermediate images between neighboring MIS phases. We used this code to generate m images of size M×M, resulting in a matrix with size M×M×M (3D solid). Finally, we show the 3D solid of the SARS-CoV-2 viral particle as part of our results in several videos, subsequently rotated and filtered to identify the glicoprotein spike protein, membrane protein, envelope, and the hemagglutinin esterase. We show the algorithms in our proposal along with the main MATLAB functions such as FourierM and Results as well as the data required for the program execution in order to reproduce our results.

Filter construction using Ronchi masks and Legendre polynomials to analyze the noise in aberrations by applying the irradiance transport equation.

We tested different optical elements placed in three different positions by applying the irradiance transport equation (ITE), obtaining the wavefront $[ W(x,y) ]$[W(x,y)] and aberration surface [$ \textit{AS}(r,\theta ) $AS(r,θ)]. The existing noise in the captures $ I $I as well as in the $ W $W and $ AS $AS were analyzed applying several filters: first a filter based on Legendre polynomials (LP), generating the most probable points increasing the data resolution; second, a filter based on a 50 deg 2D-LP was used as a multilineal fit (multiple linear regression); and third, an ideal bandpass filter in the Fourier space after inducing a periodicity using Ronchi simulated masks with periods in $ x,y,xy $x,y,xy was used to perform data scanning (similar to the four-step phase-shifting method). Signal-to-noise ratio values were obtained for each proposed filter along with the most probable image free from noise, determined from a linear combination of the original data and the applied filters.

Optical-topological concepts in isomorphisms projecting bi-Ronchi masks to obtain 3D profiles from objects in 2D images.

We introduce a technique for obtaining three-dimensional (3D) profiles of objects captured in two-dimensional (2D) flat images (FI). This technique performs a numerical approximation of the object's topography from their image gray tones, analyzing topological concepts such as algebraic bases construction, metric functions in terms of such bases, as well as modeling and development of an isomorphism to project masks (fringe patterns) in the FI, allowing us to use the optimal 3D profilometry techniques. Among these techniques, phase shifting (four steps) is applied in the pattern shifts of the projected masks, but with a 2D shift from left to right and from top to bottom, simultaneously. Moreover, the fringe patterns in the masks are binary and with superposed periods in x, y (bi-Ronchi). We show the results of the construction of the masks, as well as their projection into the FIs. We also show the 3D profilometry of the objects after the projection and phase-shifting application and a simple segmentation to observe a particular object. Subsequently, we perform the analysis of a single Mg crystal's micrography.

Two-dimensional Legendre polynomials as a basis for interpolation of data to optimize the solution of the irradiance transport equation analyzed as a boundary problem on surfaces testing.

In this paper, we give a solution to the irradiance transport equation (ITE) using the two-dimensional (2D) Legendre polynomials (LPs) and an interpolator (i-LP) based on the LP. In the first place, we analyze the experimental data; subsequently, we proceed to fit the most probable 2D LPs' surface to the data in order to obtain the wavefront surface (W(x,y) of the elements under test) as a solution of the ITE differential equation associated with a boundary problem; and finally, we interpolate the resulting fitting. The interpolation is built from LP to increase the resolution and sharpness of the data. We apply the ITE to these results in order to obtain the wavefront as a nondeterministic solution that increases the resolution of the ITE as an optical test, and we compare our results regarding the obtained aberration surfaces (AS(x,y)).

Moiré-Ronchigram analysis applied in the characterization of aberration surfaces and optical surface parameters from 3D wavefronts.

In this work, we propose the construction of the Moiré-Ronchigram as a pattern obtained from simple Ronchigrams, superposed and with a slight degree of rotation, to obtain a 3D wavefront. The aberrations in the obtained wavefront are fitted to the aberration Zernike polynomial of degree 12 in order to obtain a polynomial expression of a high degree of efficiency, which is subsequently compared with the general equation of quadrics (considering the coefficients accordingly) to obtain essential parameters (as focus, eccentricity, or F number) that allow us to understand and manipulate the optical elements under test optimally. Finally, we compare our results analyzing optical surfaces to make a weak statistic of our proposed method.

Use of autologous tooth-derived graft material in the post-extraction dental socket. Pilot study.

BACKGROUND: The objectives of the present pilot study are to compare via CBCT the alveolar contraction suffered both vertically and horizontally between the control group and the group using autologous dental material (ADM), as well as to study the densitometric differences between both post-extraction sockets. MATERIAL AND METHODS: A split-mouth study was performed in n = 9 patients who required two extraction of single-rooted teeth deemed suitable for deferred rehabilitation with osseointegrated implants. Two groups were formed - a control group, in which the post-extraction socket was not filled, and an ADM group, in which the alveolar defect was filled with freshly processed autogenous dental material. Both dimensional and densitometric analyses of the alveoli were performed in both groups immediately after surgery (baseline), as well as 8 weeks and 16 weeks later. RESULTS: The mean height of alveolar bone loss was: VL (Control 1.77 mm, loss of 16.87% of initial alveolar height; ADM 0.42 mm, loss of 4.2% of initial alveolar height), HL-BCB (Control 2.22 mm, ADM 0.16 mm, p= 0.067 at 16 weeks). The mean bone loss of the vestibular width (VL-BCB) was much higher in the control group (1.91 mm at 1 mm, 1.3 mm at 3 mm, and 0.89 mm at 5 mm) than in the ADM group (0.46 mm at 1 mm, 0.21 mm at 3 mm, 0.01 at 5 mm, p=0.098 at 16 weeks). At 16 weeks, densitometric analysis of the coronal alveolar area revealed a bone density of 564.35 ± 288.73 HU in the control group and 922.68 ± 250.82 HU in the ADM group (p=0.045 ). CONCLUSIONS: In light of these preliminary results, autologous dentine may be considered a promising material for use in socket preservation techniques.

A new mechanochemical model: coupled Ginzburg-Landau and Swift-Hohenberg equations in biological patterns of marine animals.

In this work the skin coating of some vertebrate marine animals is modeled considering only dermis, epidermis and basal layers. The biological process takes into account: cellular diffusion of the epidermis, diffusion inhibition and long-range spatial interaction (nonlocal effect on diffusive dispersal) for cells of dermal tissue. The chemical and physical interactions between dermis and epidermis are represented by coupling quadratic terms and nonlinear terms additional. The model presents an interesting property associated with their gradient form: a connection between some physical, chemical and biological systems. The model equations proposed are solved with numerical methods to study the spatially stable emergent configurations. The spatiotemporal dynamic obtained of the numerical solution of these equations, present similarity with biological behaviors that have been found recently in the cellular movement of chromatophores (as contact-dependent depolarization and repulsion movement between melanophores, xanthophores and iridophores). The numerical solution of the model shows a great variety of beautiful patterns that are robust to changes of boundary condition. The resultant patterns are very similar to the pigmentation of some fish.

Selective Pressure by Rifampicin Modulates Mutation Rates and Evolutionary Trajectories of Mycobacterial Genomes.

Resistance to the frontline antibiotic rifampicin constitutes a challenge to the treatment and control of tuberculosis. Here, we analyzed the mutational landscape of Mycobacterium smegmatis during long-term evolution with increasing concentrations of rifampicin, using a mutation accumulation assay combined with whole-genome sequencing. Antibiotic treatment enhanced the acquisition of mutations, doubling the genome-wide mutation rate of the wild-type cells. While antibiotic exposure led to extinction of almost all wild-type lines, the hypermutable phenotype of the ΔnucS mutant strain (noncanonical mismatch repair deficient) provided an efficient response to the antibiotic, leading to high rates of survival. This adaptative advantage resulted in the emergence of higher levels of rifampicin resistance, an accelerated acquisition of drug resistance mutations in rpoB (ß RNA polymerase), and a wider diversity of evolutionary pathways that led to drug resistance. Finally, this approach revealed a subset of adaptive genes under positive selection with rifampicin that could be associated with the development of antibiotic resistance. IMPORTANCE Rifampicin is the most important first-line antibiotic against mycobacterial infections, including tuberculosis, one of the top causes of death worldwide. Acquisition of rifampicin resistance constitutes a major global public health problem that makes the control of the disease challenging. Here, we performed an experimental evolution assay under antibiotic selection to analyze the response and adaptation of mycobacteria, leading to the acquisition of rifampicin resistance. This approach explored the total number of mutations that arose in the mycobacterial genomes under long-term rifampicin exposure, using whole-genome sequencing. Our results revealed the effect of rifampicin at a genomic level, identifying different mechanisms and multiple pathways leading to rifampicin resistance in mycobacteria. Moreover, this study detected that an increase in the rate of mutations led to enhanced levels of drug resistance and survival. In summary, all of these results could be useful to understand and prevent the emergence of drug-resistant isolates in mycobacterial infections.

Introducing a Combination of ICA-EMD to Suppress Muscle and Ocular Artifacts in EEG Signals.

This paper presents a combination of Independent Component Analysis (ICA) with Empirical Mode Decomposition (EMD) to suppress muscle and ocular artifacts in electroencephalographic (EEG) signals: By means of ICA, the EEG signals are decomposed into independent components. To avoid the suppression of artifactual components still containing physiological information, EMD is applied to decompose the components in Intrinsic Mode Functions (IMFs). The IMFs with mainly muscle artifacts are removed, and a new data set of independent components without muscle artifacts is generated. From this set, the components containing ocular artifacts are suppressed and clean data are reconstructed. In this way, the muscle and ocular artifacts are better suppressed than using pure ICA, or pure EMD. The performance of the proposed combination is applied to a semi-simulated data set, and three real EEG data sets from healthy subjects contaminated with both artifacts.

HARD X-RAY EMISSION DURING FLARES AND PHOTOSPHERIC FIELD CHANGES.

We study the correlation between abrupt permanent changes of magnetic field during X-class flares observed by the Global Oscillation Network Group and Helioseismic and Magnetic Imager instruments, and the hard X-ray (HXR) emission observed by RHESSI, to relate the photospheric field changes to the coronal restructuring and investigate the origin of the field changes. We find that spatially the early RHESSI emission corresponds well to locations of the strong field changes. The field changes occur predominantly in the regions of strong magnetic field near the polarity inversion line (PIL). The later RHESSI emission does not correspond to significant field changes as the flare footpoints are moving away from the PIL. Most of the field changes start before or around the start time of the detectable HXR signal, and they end at about the same time or later than the detectable HXR flare emission. Some of the field changes propagate with speed close to that of the HXR footpoint at a later phase of the flare. The propagation of the field changes often takes place after the strongest peak in the HXR signal when the footpoints start moving away from the PIL, i.e., the field changes follow the same trajectory as the HXR footpoint, but at an earlier time. Thus, the field changes and HXR emission are spatio-temporally related but not co-spatial nor simultaneous. We also find that in the strongest X-class flares the amplitudes of the field changes peak a few minutes earlier than the peak of the HXR signal. We briefly discuss this observed time delay in terms of the formation of current sheets during eruptions.

Bone marrow toxicity after yellow phosphorus ingestion.

Suicidal ingestions of fireworks containing yellow phosphorus occur often during holidays. A case is reported of a 17 year old woman who intentionally ingested an estimated amount of 5.5 mg of yellow phosphorus, presenting with upper abdominal pain as the only complaint, a physical examination was normal. Blood tests showed a considerable decrease in the granulocyte count; the bone marrow biopsy revealed a decreased cellular mass with degenerative changes. Spontaneous remission was observed during the next 48 hours, with no further complaints.

Prototipo de Silla de Ruedas Dirigida Usando Parpadeos / A Wheel Chair Prototype Moved by means of Eye Blinks

Resumen El presente trabajo describe un prototipo de una silla de ruedas que es dirigido hacia enfrente y hacia atrás usando 2 o 3 parpadeos, respectivamente, y es detenido cuando se alcanzan ciertos niveles de atención. El objetivo principal es que las personas que tienen discapacidad motora en sus extremidades puedan usarlo para desplazarse y les brinde autonomía. Para captar la señal de los parpadeos, se utilizó la diadema MindWave Mobile de Neurosky. Se implementó un circuito electrónico en conjunto con Arduino que permite complementar la ejecución del accionamiento del prototipo. El prototipo se probó con 10 personas cuyas edades oscilan entre 20 y 35 años. Los resultados muestran que, en un 80% de los casos, el prototipo se mueve correctamente. La gran ventaja del presente trabajo es que la interfaz cerebro-computadora con la que cuenta este prototipo no requiere entrenamiento previo del sistema, por lo cual, puede ser usado por cualquier persona. Además, su costo es más accesible comparado con otros dispositivos para el mismo fin.

Abstract The present work describes a prototype of a wheel chair directed by means of eye blinks, which can be moved forwards, and backwards using 2 or 3 eye blinks, respectively, and stopped when a certain attention level is met. The main objective of this work is to help people, who have motor disabilities on their arms and legs, move and have autonomy. In order to register the eye blinking signals, the MindWave Mobile device from Neurosky was used. Moreover, an electronic circuit in combination with Arduino has been used to make the prototype work. This prototype has been tested in 10 healthy people from 20 to 35 years old. According to the results, in 80% of the cases the prototype worked correctly. The main advantage of the present work is that the brain-computer interface, which is part of the prototype, does not require training, and hence, it could be used by most of the people. Moreover, its cost is less than similar devices.

Identificación Estable de Fuentes Asociadas a Focos Epilépticos Ubicadas sobre la Corteza / Stable Identification of Sources Associated with Epileptic Focus on the Cerebral Cortex

Resumen Objetivo: Presentar un algoritmo estable que determina, a partir de mediciones electroencefalográficas, los parámetros de fuentes de tipo dipolar asociadas a focos epilépticos ubicados sobre la superficie de la corteza cerebral. Metodología: Se utiliza un problema de contorno para establecer correlaciones entre la fuente y la medición. El problema se divide en dos subproblemas lineales y en cada uno de ellos, se utilizan el método de mínimos cuadrados y la regularización de Tikhonov para encontrar soluciones estables. Estos subproblemas son problemas mal planteados en el sentido de Hadamard, debido a la inestabilidad numérica que presentan, es decir, pequeños cambios en las mediciones pueden producir grandes variaciones en la solución de cada problema. El parámetro de regularización de Tikhonov fue elegido usando el método de la curva L. Para hallar la solución del problema de contorno se utiliza el método de las series de Fourier y el Método del Elemento Finito. Resultados: Se propuso un tipo de fuente para representar a los focos epilépticos en la corteza cerebral y un algoritmo estable para el problema de identificación de los parámetros de dichas fuentes. Se desarrollaron ejemplos sintéticos y programas en MATLAB para el caso de geometría simple bidimensional. Originalidad: La separación del problema original en dos subproblemas así como los ejemplos sintéticos son producto de esta investigación. Conclusión general: Se propuso un algoritmo estable que determina a los parámetros de fuentes de corriente dipolar definidas en la corteza cerebral.

Abstract Objective: To present a stable algorithm that determines, from electroencephalographic measurements, the parameters of dipolar sources associated with epileptic foci located on the cerebral cortex. Methodology: A boundary value problem is used to establish correlations between the sources and the measurements. The problem is divided into two linear subproblems and in each one, the method of Minimum Square and the Tikhonov regularization are used for finding stables solutions. These subproblems are an ill-posed problem in the Hadamard sense, which is due to the numerical instability, that is, small changes in the data can produce substantial variations in the solution of each problem. The Tikhonov regularization parameter was chosen using the L curve method. To find the solution of the boundary value problem are used the Fourier series method and the Finite Element Method. Results: A type of source that represents the epileptic foci on the cerebral cortex and a stable algorithm for finding the parameter of these sources were proposed. Synthetics examples and MATLAB programs were developed for the case of bidimensional geometry. Originality: The separation of the original problem into two subproblems and the synthetics examples are a product of this research. Conclusion: A stable algorithm was proposed for determining the parameters of the dipolar current defined on the cerebral cortex.

Analysis of the Inverse Electroencephalographic Problem for Volumetric Dipolar Sources Using a Simplification / Análisis del Problema Inverso Electroencefalográfico para Fuentes Dipolares Volumétricas por Medio de una Simplificación

Objective: To analyze the parameter identification problem for volumetric dipolar sources in the brain from measurement of the EEG on the scalp using a simplification which reduces the multilayer conductive medium problem to one homogeneous medium problem with a null Neumann boundary condition. Methodology: The minimum squares technique is used for parameter identification of the dipolar sources. The simple case in which the head is modelled by concentric circles is developed. This case was chosen because we were able to obtain the solution of the forward problem in exact form and for the simplicity of the exposition. Results: The parameter of the dipolar sources can be identified from the EEG on the scalp using the simplification. For the theoretical analysis the results developed for one homogeneous region are used. The numerical implementation is simpler than the multilayer case and the numerical computation requires minor computational cost. Conclusion: The feasibility for solving the parameter identification problem using the simplification is shown. These results can be extended to the case of concentric spheres and complex geometries but the solution cannot be found in exact form.

Objetivo: Analizar el problema de identificación de los parámetros para fuentes dipolares volumétricas en el cerebro a partir de la medición del EEG en el cuero cabelludo mediante una simplificación que reduce el problema de un medio conductor de múltiples capas a un problema en un medio homogéneo con una condición de Neumann nula en su frontera. Metodología: Se utiliza la técnica de mínimos cuadrados para identificar los parámetros de las fuentes dipolares. Se desarrolla el caso simple en el que la cabeza está modelada por círculos concéntricos debido a que la solución del problema directo se puede calcular en forma exacta y por la sencillez de la exposición. Resultados: Se identifican los parámetros de la fuente dipolar a partir del EEG sobre el cuero cabelludo usando la simplificación. Para el análisis teórico se utilizan los resultados desarrollados para una región homogénea. La implementación numérica es más simple y el cálculo numérico requiere menor costo computacional. Conclusión: Se muestra la factibilidad para resolver el problema de identificar los parámetros de una fuente dipolar por medio de la simplificación. Los resultados pueden ser extendidos al caso de esferas concéntricas y al de geometrías complejas pero la solución del problema directo no puede hallarse en forma exacta.

Simplificación del problema inverso electroencefalográfico a una sola región homogénea con condición de Neumann nula / Simplification of the Inverse Electroencephalographic Problem to One Homogeneous Region with Null Neumann Condition

Objetivo: Presentar una simplificación del Problema Inverso Electroencefalográfico (PIE) del caso de varias capas conductoras a una región homogénea con condición de Neumann Nula. Metodología: Se divide el PIE en tres problemas, dos de los cuales se resuelven usando el potencial medido en el cuero cabelludo y con estas soluciones y el tercer problema se lleva a cabo la simplificación. Para validar la simplificación se genera un ejemplo sintético usando el modelo de esferas concéntricas. Resultados: Por medio de la simplificación la fuente se determina a partir de la ecuación de Poisson con una condición de Neumann nula y un dato adicional sobre la frontera de la región homogénea, el cual se obtiene de la medición. Esto es válido para regiones generales con fronteras suficientemente suaves. Adicionalmente, para el caso de esferas concéntricas, se plantea el PIE para el caso de una fuente dipolar (que representa a focos epilépticos) usando esta simplificación y la técnica de la función de Green. Conclusión: La simplificación presentada aquí permite analizar el PIE en una región lo cual simplifica su estudio teórico y numérico. En particular, puede ser útil para el análisis del problema de identificación de los parámetros de una fuente dipolar.

Objective: To give a simplification of the Inverse Electroencephalographic Problem (IEP) from the case of multilayer conductive medium to the case of a homogeneous region with null Neumann condition. Methodology: IEP is divided in three problems, two of which are resolved using the measurements of potential on the scalp and with these solutions and the third problem the simplification is carried out. In order to validate the simplification a synthetic example is generated using the model of concentric spheres. Results: Through of simplification, the source is determined from the Poisson equation with null Neumann condition and an additional data on the boundary of the homogeneous region, which is obtained from the measurement. This is valid for regions with smooth boundary. Additionally, in the case of concentric spheres, it is statement the identification problem for dipolar sources (representing epileptic focus) using this simplification and Green function. Conclusion: The simplification presented here allows us to analyze the inverse problem in one region, which simplifies the theoretical and numerical study. In particular it may be useful to analyze the problem of parameter identification of a dipolar source.

Clinical, pathological and toxicological findings of a iatrogenic selenium toxicosis case in feeder pigs.

Histopathological and toxicological analyses confirmed a clinical diagnosis of selenium (Se) intoxication in pigs from a farm in Spain. After an initial episode of diarrhoea, animals presented both dermatological and neurological signs; the most obvious sign was a marked hind limb paresis. Cutaneous lesions consisted on diffuse alopecia, multifocal skin necrosis and coronary band necrosis of the hooves. Central nervous system lesions involved the cervical and lumbar intumescences of the spinal cord and consisted of a severe, bilateral symmetrical poliomyelomalacia of the ventral horns; pons and medulla oblongata also presented lesions of polioencephalomalacia. Analyses of feed and sera from clinically affected pigs revealed a marked increase in Se concentration. Clinical investigations indicated that a failure in Se dosage in feed was the cause of the toxicosis.

Changes in EEG alpha power induced by repetitive ipsi- and contralateral hand movements.

Changes in alpha activity induced by hand movements, both ipsi and contralateral to left brain hemisphere were studied. Seven channels of EEG (F3, C3, P3, O1, T3, T5 and CZ referred to nasion) were processed by a minicomputer. The values which correspond to three tasks (rest, right hand and left hand movement) were analyzed by means of an ANOVA of three factors. Our data bring us to the following conclusions: The two movements (left and right hand) cannot be differentiated by alpha band power in any electrode position and both of them decrease the alpha power significantly. This decreasing effect is not homogeneous in the whole hemisphere, being greater in the central area.

Mining functional information associated with expression arrays.

Deciphering the networks of interactions between molecules in biological systems has gained momentum with the monitoring of gene expression patterns at the genomic scale. Expression array experiments provide vast amounts of experimental data about these networks, the analysis of which requires new computational methods. In particular, issues related to the extraction of biological information are key for the end users. We propose here a strategy, implemented in a system called GEISHA (gene expression information system for human analysis) and able to detect biological terms significantly associated to different gene expression clusters by mining collections of Medline abstracts. GEISHA is based on a comparison of the frequency of abstracts linked to different gene clusters and containing a given term. Interpretation by the end user of the biological meaning of the terms is facilitated by embedding them in the corresponding significant sentences and abstracts and by establishing relations with other, equally significant terms. The information provided by GEISHA for the available yeast expression data compares favorably with the functional annotations provided by human experts, demonstrating the potential value of GEISHA as an assistant for the analysis of expression array experiments.