Summary: The continuous changes in the use of soil for agricultural and livestock activities, as well the geographical location on sites affected by continuous wind currents, have caused changes in soil characteristics in a period of 40 years. To identify such changes, this study was performed in the north of the state of Zacatecas. The results of soil from 300 samples obtained in the laboratory analysis in 1976 were compared against an equal number of samples obtained in 2016. “Raster” images were generated by georeferencing the sampling sites and interpolating with “kriging”. The coinciding determinations between databases showed the differences between them by overlapping both images. The wind erosion was estimated and the levels of erosion associated with the sites where the changes occurred. The image analysis shows a matching area where sand content and soil pH increased. Such surface represents 401 907 ha of 2 118 000 ha covered by the images, where calcium has decreased in 98% of the surface, as well as potassium (59%), organic matter (58%), magnesium (49%) and sodium (35%) in 40 years, identifying areas of accumulation and soil loss associated with values of wind erosion. The prevailing SW winds that cause wind erosion were identified with values from 8 to 32 Mg ha-1 in 100 209 ha of accumulation and 233 587 ha of losses in 40 years. Of the total identified, 199 753 ha are agricultural areas and 202 154 are for livestock use. The identification of areas should help define plans and public policies for technological intervention.

Resumen: Los cambios continuos en el uso del suelo en actividades agrícolas y pecuarias, así como, la ubicación geográfica en sitios afectados por corrientes continuas de viento, han provocado cambios en las características del suelo en un periodo de 40 años. Para identificar tales cambios, se llevó a cabo el presente estudio en la región norte del estado de Zacatecas. Se utilizaron resultados de análisis de laboratorio de 300 muestras obtenidas en 1976 que fueron comparadas contra un número igual de muestras obtenidas en 2016. Al ubicar los sitios de muestreo se generaron imágenes “raster”, por interpolación con “kriging”. Se encontraron diferencias de las determinaciones coincidentes entre ambas bases de datos, al sobreponer ambas imágenes. Se estimó la erosión eólica de 2016 y se asoció los niveles de erosión con los sitios donde se presentaron los cambios. El traslape de imágenes muestra un área de coincidencia donde se incrementó el contenido de arena y el pH del suelo. Tal superficie representa 401 907 ha, de un total de 2 118 000 ha cubiertas por las imágenes. En ella se encontró que en 40 años ha disminuido el calcio en 98% de la superficie, así como, el potasio (59%), la materia orgánica (59%), magnesio (49%) y sodio (35%) con lo que se identificaron áreas de acumulación y pérdidas de suelo asociadas a valores altos de erosión eólica. Se identificaron los vientos predominantes del suroeste que provocan la erosión eólica con valores de 8 a 32 Mg ha-1 en 100 209 ha de acumulación y 233 587 ha de pérdidas en 40 años. Del total identificado 199 753 ha son áreas agrícolas y 202 154 son de uso pecuario. La identificación de áreas ayudará a definir planes y políticas públicas de intervención tecnológica.

Resumen La interacción entre la capa freática salina y somera y la agricultura intensiva da lugar a un frágil equilibrio entre la acumulación y lixiviación de sales en los suelos de marisma recuperada del sector de riego B-XII, en el suroeste de España. Evaluamos el potencial de la tomografía de inducción electromagnética (EMI) e imágenes de NDVI de Sentinel 2 para el seguimiento de la salinidad del suelo a escala de parcela en esta zona, usando mediciones de la conductividad eléctrica aparente (ECa) del suelo realizadas en 2017 y 2020. Las estimaciones de la conductividad eléctrica (EC) obtenidas mediante inversión de la ECa mostraron una fuerte correlación (R≈0,90) con la conductividad del extracto de pasta saturada (ECe) y la relación de absorción de sodio (SAR), lo que dio lugar a ecuaciones de calibración lineales con R2≈0,80 para ambos años y resultados de validación cruzada de exclusión (LOOCV) fiables para los horizontes subsuperficiales de 0,55 < R2 < 0,81. El patrón espacial de EC mostró correlación inversa con el del NDVI para tomate para industria, algodón y remolacha cultivados entre los años 2017 y 2019, alcanzando valores R de -0,64, -0,87 y -0,73, respectivamente.

Abstract The presence of a shallow saline water table in combination with intensive agriculture in the reclaimed marshes of the B-XII irrigation district, in SW Spain, may disrupt the fragile balance between salt accumulation and leaching in the root zone. We evaluate the potential of electromagnetic induction tomography (EMI) and the use of Sentinel 2 NDVI imagery for field-scale soil salinity monitoring using soil apparent electrical conductivity (ECa) measured in 2017 and 2020. Depth-specific electrical conductivity (EC), obtained from the inversion of ECa, showed a strong correlation (R≈0.90) with laboratory-analysed saturated paste extract conductivity (ECe) and sodium adsorption ratio (SAR), resulting in linear calibration equations with R2≈0.80 for both years and reliable cross-validation of exclusion (LOOCV) results for the subsoil (0.55 < R2 < 0.81). The spatial pattern of EC showed inverse correlation with NDVI for processed tomato, cotton and sugar beet, cropped between 2017 and 2019, reaching R values of -0.64, -0.87 and -0.73, respectively.

Abstract Submesoscale eddies (1-10 km diameter) were identified using surface velocity observations obtained from a high-frequency radar system (HFR) operated in Todos Santos Bay (TSB), Baja California, Mexico. Eddies were detected through a special case of the Okubo-Weiss parameter for divergent flows in the form of eigenvalues of the Jacobian matrix. The detection method, applied for a surface velocity grid, shows encouraging results in the recognition and tracking of submesoscale features in TSB. The detection method is rapid and efficient. Results show the formation and persistence of an eddy structure inside the Bay in December 6, 2010, displaying a trajectory from NE to SW until disappearing at the center of the Bay. The eddy is approximately 4 km in diameter with a frequency of ~0.1f (f is the Coriolis parameter). The real part of the Okubo-Weiss parameter ranged between − 4 × 10 − 9 to − 1 × 10 − 9 s − 2, and outlined the eddy for approximately 9 hours. Although it is difficult to identify the origin of the detected submesoscale eddy, its appearance coincided with a drop in relative atmospheric humidity suggesting land-ocean Santa Ana winds as a possible generating mechanism.

Resumen Después de la cosecha del fruto chirimoya, los árboles liberan enormes cantidades de hojas, las cuales son quemadas por los agricultores. Este trabajo muestra que las hojas pueden ser usadas para nuestro beneficio como antioxidante. Se determinaron los compuestos fenólicos (CF) y la actividad antioxidante (AA) de los extractos de la hoja seca de Annona cherimola Mill en etanol al 70% v/v, agua a 80 °C, y agua subcrítica (AS) a 110, 120 y 130 °C, siguiendo un diseño factorial con el programa Minitab. Los CF se cuantificaron con la metodología de Folin Ciocalteu y la AA con el 2,2-difenil-1-picrilhidrazilo (DPPH) y con el poder antioxidante reductor del hierro (FRAP). Los resultados indicaron que el tipo de solvente y el tiempo de extracción presentaron un efecto significativo en el contenido de CF y AA de los extractos. Se concluyó que el extracto de hoja de chirimoya es un potencial antioxidante. El extracto de AS a 130 °C presentó el mayor contenido de CF (5,6 g EAG/100 g de hoja seca) y el extracto etanólico presentó mayor AA (0,86 mg equivalente trolox/mg extracto seco; IC50=0,020 mg de extracto seco/mL de extracto de hoja seca y FRAP de 1710,14 μmol equivalente trolox /g de hoja seca) y los extractos obtenidos con AS a menor temperatura presentaron mayores valores de AA.

Abstract After harvesting cherimoya fruit, the trees release huge amounts of leaves, which are burned by farmers. This work shows that the leaves can be used as a source of antioxidants. Total phenolic compounds (TPC) and antioxidant activity (AA) of extracts of the dry leaf of Annona cherimola Mill in 70% v/v ethanol, water at 80 °C, subcritical water (SW) at 110 °C, 120 °C and 130 °C were determined, following a factorial design with the Minitab program. The TPC was quantified with the Folin Ciocalteu methodology, and the AA with 2,2-diphenyl-1-picrilhidrazil (DPPH) and Ferric Reducing Antioxidant Power (FRAP). Results indicate that the type of solvent and the extraction time had a significant effect on the TPC and AA of the extracts. Extracts of cherimoya leaves were found to be a potential antioxidant. The extract of SW at 130 °C presented the highest content of TPC (5.6 g EAG/100 g dry leaves) and the ethanolic extract had the highest AA (0.86 mg trolox equivalent/mg dry extract, IC50 = 0.020 mg dry extract/mL extract of dry leaves and FRAP of 1710.14 μmol ET/g dry leaves) and the extracts obtained with SW at a lower temperature presented a higher AA value.

Resumo Depois da colheita da fruta Cherimoya, as árvores liberam grandes quantidades de folhas, que são queimadas pelos agricultores. Este trabalho mostra que as folhas podem ser usadas para nosso benefício como um antioxidante. Compostos fenólicos (FC) e a actividade antioxidante (AA) de extractos de folha seca Annona cherimola Mill em etanol a 70% v/v água a 80 °C, água subcrítica (AS) 110, 120, 130 °C, foram determinados seguindo um planejamento fatorial com o programa Minitab. Os FC foram quantificados com a metodologia Folin Ciocalteu; e a capacidade antioxidante (AA) com 2,2-difenil-1-picrilhidrazil (DPPH) e poder antioxidante redutor de ferro (FRAP). Os resultados indicaram que o tipo de solvente e o tempo de extração tiveram um efeito significativo no conteúdo deCFeAA dos extratos. Conclui-se que o extracto de folha de cherimoya é um potencial antioxidante, o extracto de AS 130 °C tinha o maior conteúdo de CF (5,6 g EAG/100 g folha seca) e o extracto etanólico mostraram maior AA (0,86 mg equivalente Trolox/mg extrato seco, IC50 = 0,020 mg extrato seco/mL extracto de folha seca e FRAP de 1710,14 μmol ET/g folha seca). Os extratos obtido com AS a uma temperatura mais baixa apresentaram um maior valor de AA.

Abstract The design and simulation of a Full-Bridge Flying-Capacitor Multilevel-Inverter (FB-FCMI) for high-voltage applications are presented. The power inverter topology consists of two legs: each one with three commutation cells, six switches and two flying-capacitors. The proposed control system provides twelve square signals for all switches that compose the inverter, which is driven at a commutation frequency f SW ≈6.66 kHz. The output frequency f 0, is equal to three times the commutation frequency. The inductor and capacitor in the resonant-circuit design is calculated based on f 0, which depends on the number of cells, N. The goal of the proposed inverter design is to demonstrate that, the output frequency increases as rate of f 0 = N∙ f SW. In order to show the effect of the increase in the number of cells, a resonant power inverter is designed and simulated, first with three and then with six switching cells, at f 0 = 20 kHz. Finally, the FB-FCMI is connected to the primary winding of the high-voltage transformer, while the secondary is coupled to a Dielectric Barrier Discharge reactor represented by its electrical model, to generate an electrical discharge in helium.

Resumen Se presenta el diseño y simulación de un Inversor Multinivel de Capacitores Flotados (FB-FCMI, por sus siglas en inglés) en puente completo para aplicaciones de alto voltaje. La topología del inversor de potencia consiste en dos ramas, cada una con tres células de conmutación, seis interruptores y dos condensadores flotados. El sistema de control proporciona doce señales cuadradas para todos los interruptores que componen el inversor, que se opera a frecuencia de conmutación f SW ≈6.66 kHz. La frecuencia de salida es f 0, y es igual a tres veces la frecuencia de conmutación. El diseño del inductor y condensador del circuito resonante se calcula con base en f 0, que está en función del número de células, N. El objetivo del diseño del inversor propuesto es demostrar que, la frecuencia de salida incrementa en proporción de f 0 = N∙ f SW. A fin de que se observe el efecto por el incremento en el número de células, un inversor resonante de potencia se diseña y simula, primero con tres y después con seis células de conmutación, a f 0 = 20 kHz. Finalmente, el FB-FCMI se conecta al primario de un transformador de alto voltaje, mientras que el secundario se acopla a una descarga de barrera dieléctrica para generar una descarga eléctrica en helio.

Resumo O presente estudo, realizado no arquipélago de Fernando de Noronha (4ºS/32ºW), teve como objetivo a avaliação da distribuição espacial e variações sazonais dos sedimentos e matéria orgânica sedimentar da plataforma insular norte de Fernando de Noronha ("Mar de Dentro"). Ao todo, 19 amostras de sedimentos foram coletadas entre dezembro de 2013, julho de 2014 e novembro de 2014. Os métodos analisados foram a granulometria, análise da fração arenosa, morfoscopia, teores de matéria orgânica total, carbonato de cálcio, carbono orgânico, nitrogênio total, fósforo sedimentar (orgânico, inorgânico e total), razões elementares (C/N e C/P) e razões isotópicas estáveis (δ13C e δ15N). Os resultados obtidos permitiram inferir que não há variação sazonal na distribuição sedimentar. Visto que os sedimentos da plataforma apresentam uma cobertura sedimentar carbonática (CaCO3≈ 88,3%), predominantemente de areias finas bem selecionadas, com baixos conteúdos orgânicos (MOT<2,87%, COT<4,29%, PT<0,44µmol/g) de origem marinha (δ13C≈ -22,17%PDB) em todos os períodos. Como conclusão, observou-se que ocorre uma mudança espacial, onde a parte SW é mais cascalhosa e a porção NE composta por areia fina, condicionada pela morfologia de fundo, fontes de sedimentos e ação das ondas. A geoquímica evidenciou algumas estações mais enriquecidas, com matéria orgânica (COT>3,0%; NT>0,4%) de origem mista (δ13C= -24,5 a -23,0%PDB), que foram associadas aos inputs antrópicos e aos processos bióticos e abióticos locais.

Abstract The present study was conducted in the Fernando de Noronha archipelago (4°S/32°W). The objective is the evaluation of the spatial distribution and seasonal variations in the sediments and sedimentary organic matter in the northern insular shelf of Fernando de Noronha ("Mar de Dentro"). Nineteen surface sediment samples were collected between December 2013, July 2014 and November 2014. The studied methods included analysis of the grain size, coarse fraction, morphoscopy, total organic matter content, calcium carbonate, organic carbon, total nitrogen, sedimentary phosphorus (organic, inorganic and total), elemental ratios (C/N, C/P) and stable isotopic ratios (δ13C-δ15N). The results allowed to infer that there is no seasonal variation in sediment distribution. Whereas, the shelf sediments present a calcareous sandy sedimentary cover (CaCO3≈ 88.3%), predominantly of well-sorted fine sands, with low organic matter content (TOM<2.87%, TOC<4.29%, TP<0.44µmol/g) and are mainly of marine origin (δ13C ≈ -22.17%PDB). As conclusions was observed a spatial variation, where the southwestern part is dominated by gravelly and northeast part is composed for fine sand, conditioned by the bottom morphology, sediments sources and, wave action. The geochemistry showed some stations with relative enrichment in organic matter content (TOC>3.0%; TN>0.4%) of mixed origin (δ13C= -24.5 to -23.0%PDB), which were related to anthropogenic impacts and the biotic and abiotic local processes.

Del fraccionamiento del extracto etanólico de hojas de Piper hispidum Swartz, se aisló e identificó cuatro productos descritos previamente en la bibliografía, pero reportados por primera vez en esta especie: P1 (5-hidroxi-7,4'-dimetoxiflavanona), P2 (oxido de cariofileno), P3 (esfatulenol) y P4 (trans-fitol). Sus estructuras fueron elucidadas en base a los datos de RMN 1H y 13C, incluyendo las correlaciones heteronucleares HSQC, HMBC y comparación con la literatura. La actividad leishmanicida de los compuestos fue ensayada contra dos cepas de Leishmania: L. amazonensis, L. braziliensis. Los resultados demostraron que la flavanona P1(5-hidroxi-7,4'-dimetoxiflavanona) presenta un CI5014.1 y 13.1 μg/mL y el terpeno P2 (oxido de cariofileno) una CI50 36.7 y 26.8 μg/mL, compuestos moderadamente activos comparados con la anfotericina B CI50=0.21 y 0.09 μg/ mL para ambas cepas.

Fractionation of ethanol extract of leaves of Piper hispidum Swartz were isolated and identified four products previously founds in bibliography, but first reported in this species: P1 (5-hydroxy-7, 4 '-dimetoxiflavanone), P2 (caryophyllene oxide), P3 (sphatulenol) and P4 (trans-phytol). Their structures were elucidated on the basis of data from 1H and13C NMR, including heteronuclear correlations HSQC, HMBC and comparison with the literature found. Leishmanicidal activity of the compounds was tested against two strains of Leishmania: L. amazonensis, L. braziliensis. The results showed that flavanone (5-hydroxy-7, 4'-dimetoxiflavanona) with IC50= 14.1 and 13.1 μg/mL, and terpene (caryophyllene oxide) with IC50 = 36.7 and 26.8 μg/mL were moderately active compared with Amphotericin B IC50 = 0.21 and 0.09 μg/mL for both strains.

Two magnetotelluric (MT) profiles perpendicular to the trench provide information on the subduction of the Rivera plate under the Jalisco block (JB). The geometry of the subducting slab is inferred by the anomalous conductor on the top of the profile in the central part of the JB. High conductivity zones (<50 ohm-m) at depths shallower than 10 km are associated to dewatering of the oceanic crust below the accretion prism in the SW of the profile. Away from the coast, observed upper crustal conductors (<10 km) are interpreted as partial melt related to the Central Jalisco volcanic lineament. The source of the crustal conductor in the central part of the MT profile, ~25-75 km inland and depths between 40 and 60 km, is interpreted as a region of interconnected fluids associated with the metamorphic dehydration of the oceanic plate. Contrasting resistivity in the mantle wedge at depths below 40 km suggests that hot mantle material may be migrating upwards, mixing with dehydration reaction products. Near Bahla de Banderas subduction appears steeper closer to the trench than toward the SW suggesting a twisted oceanic subducting slab beneath the continental crustal block. Our results support the mantle upwelling model as an explanation for the reported 1.5 km uplift of the central part of the JB and subsidence of the fore arc region, as well as a change in mantle properties at the NW edge of the JB, which is backed by seismic data.

Dos perfiles magnetotelúricos (MT) perpendiculares a la trinchera proporcionan información del proceso de subducción de la placa de Rivera debajo del bloque de Jalisco (BJ). A partir del conductor anómalo inclinado que se asocia a la interface activa se deducen rasgos de la geometría de la placa que subduce. Zonas de conductividad anómala (<50 ohm-m) a profundidades inferiores a los 10 km se asocian a la deshidratación de la corteza oceánica debajo del prisma de acreción en el SW del perfil. Lejos de la costa, los conductores observados a profundidades de la corteza superior (<10 km) se interpretan como zonas de fusión parcial relacionadas al lineamiento volcánico de Jalisco Central. La fuente de la zona conductora cortical en la parte central del perfil MT, aproximadamente 25 a 75 km dentro del continente y entre los 40 y 60 km de profundidad, se interpreta como una región de fluidos interconectados asociados con la deshidratación de la corteza oceánica por procesos de metamorfismo. El contraste de resistividades en la cuña del manto debajo de ~40 km sugiere la migración ascendente de material caliente del manto que se mezcla con productos de reacciones metamórficas de la placa oceánica. El proceso de subducción de la placa de Rivera ocurre a un ángulo más pronunciado y más cercano a la trinchera en la parte noroeste que hacia la parte sureste de la zona de subducción, lo que sugiere una placa oceánica flexionada hacia el NW debajo del bloque de corteza continental. Nuestros resultados apoyan un modelo de ascenso del manto en la parte centro oriental del BJ, que explica el levantamiento topográfico de más de 1.5 km y la subsidencia en la zona del ante-arco reportada, además de un cambio en las propiedades eléctricas del manto en la zona, que parecen variar rápidamente, como lo sugieren también los datos sísmicos.

Se presenta el estudio bioestratigráfico semicuantitativo de nanofósiles calcáreos para tres secciones estratigráficas del Mioceno superior de la costa Pacífica de Colombia (SW de la Cuenca Tumaco costa adentro). Para establecer la biocronología de las asociaciones de nanofósiles recuperadas se identificaron las biozonas estándar y se compararon los bioeventos reconocidos con las edades obtenidas en otros estudios (e.g. ODP leg 138, ODP Leg 165). Un total de seis bioeventos fueron reconocidos, incluyendo los primeros registros o lower occurrence (LO) de Amaurolithus primus, Reticulofenestra rotaria, Amaurolithus delicatus, Amaurolithus amplificus y Amaurolithus tricorniculatus, y el último registro o highest occurrence (HO) de Reticulofenestra rotaria. Los resultados sugieren que las secciones abarcan un intervalo de tiempo entre el Tortoniense y el Mesiniense, correspondiente a las biozonas NN11a - NN11b de Martini (1971) y CN9a - CN9b de Okada and Bukry (1980).

A semiquantitative biostratigraphic study of calcareous nannofossils for three upper Miocene stratigraphic sections on the Pacific coast of Colombia (SW of the Tumaco onshore basin) is presented. To stablish the biochronology of the recovered nannofossils assemblages, standar biozones and previous recognized bioevents were identified and compared with other studies (e.g. ODP Leg 138, ODP Leg 165). A total of six bioevents were reconigzed, including the first record or lower occurrence (LO) of Amaurolithus primus, Reticulofenestra rotaria, Amaurolithus delicatus, Amaurolithus amplificus and Amaurolithus tricorniculatus, and the last record or highest occurrence (HO) of Reticulofenestra rotaria. Results suggest that the sections comprise a Tortonian to Messinian time interval, corresponding to the NN11a - NN11b biozones of Martini (1971) and CN9a - CN9b of Okada and Bukry (1980).

In this study we report the characterization of a leachate contaminated site, by following a methodology that integrates geophysical and geohydrological data to better constrain a hydrogeological model. The characterization of the site (subsurface structure, soil characteristics) included six seismic refraction profiles, three electromagnetic lines using transient domain electromagnetic soundings (TDEM), two electric resistivity tomography (ERT) profiles, five vertical electrical sounding (VES) and geohydrological testings and analysis to support the delimitation of the contaminant plume. The study area corresponds to the leachate lagoon of Oaxaca City landfill, southern Mexico. Its inferred hydrogeological model constitutes an example of the uselfuness of the integration of several diverse methods applied with the same objective, thus reducing the ambiguity of applying a single characterization technique. The results indicate that low resistivity values from 1.5 to 2.5 Ohm-m are related to a leachate polluted soil underlying the leachate lagoon and also associated with an anomaly enclosed in the rockbed. A displacement of the polluted plume to the SW from the lagoon was also detected. Water quality is quite good but the human activity in the study area confers a risk to the Zaachila aquifer.

Se reporta en este estudio la caracterización de una zona contaminada por lixiviados, siguiendo una metodología que integra datos geofísicos y geohidrológicos para proponer un modelo hidrogeológico del fenómeno. La caracterización del sitio (la estructura del subsuelo, y las características del suelo) incluyó seis perfiles sísmicos de refracción, tres líneas electromagnéticas (FDEM), dos perfiles eléctricos (ERT), cinco sondeos eléctricos verticales (SEV), y una serie de pruebas geohidrológicas para delimitar la pluma contaminante. El área de estudio corresponde a la laguna de lixiviados del relleno sanitario de la ciudad de Oaxaca, sur de México. El modelo hidrogeológico que se presenta constituye un ejemplo del potencial de la integración de varios métodos aplicados con el mismo objetivo; reduciendo así la ambigüedad de la respuesta geofísica. Los resultados indican que los valores de baja resistividad (1.5 a 2.5 Ohm-m) se relacionan con un suelo contaminado subyaciendo a la laguna de lixiviados y al medio fracturado. También se detectó un desplazamiento de la pluma contaminante hacia el SW de la laguna. La calidad del agua es buena, pero la actividad humana en el área de estudio confiere un riesgo para el acuífero superficial de Zaachila.

Objective. A computerized version of the Schaltenbrand and Wahren's stereotactic brain atlas for image-guided functional neurosurgery planning has been developed and integrated into our PC-based planning system. Methods. The SW atlas plates were digitized, contoured and labeled for both hemispheres. The computerized atlas may be interactively registered with patient's data using linear and non-linear transformation. The implemented computational tools and applications are presented. Results. Our computer system permits navigation through original or reconstructed slices, multiple-views synchronization and zoom to improve the localization of the commisures and the surgical targets, likewise the optimum path selection. Atlas position in the target’s region can be interactively actualized and lesion’s position and volume may be simulated. Conclusions. Its benefits of this approach include increased accuracy of target definition, decreased the number of electrode tracts and for instance the time of the surgery, and reduced surgical complications.

Objetivo. Desarrollar un atlas estereotáctico computarizado de Schaltenbrand y Wahren para la planificación de neurocirugías funcionales guiadas por imágenes. Este atlas está integrado al sistema de planificación STASSIS, desarrollado para computadoras personales. Métodos. Los cortes originales del atlas fueron digitalizados y se trazaron los contornos para ambos hemisferios. El corregistro del atlas con las imágenes del paciente se realiza mediante transformaciones rígidas y no rígidas. Se presentan las herramientas computacionales implementadas y sus aplicaciones durante el procedimiento quirúrgico. Resultados. El sistema permite la navegación continua tanto a través de los cortes originales como de las reconstrucciones, la sincronización de múltiples vistas y el uso de ampliaciones, lo que permite incrementar la exactitud en la localización de las comisuras y los blancos quirúrgicos, así como la selección óptima de las trayectorias. Los contornos del atlas se pueden ajustar a la anatomía del paciente. La posición del atlas en la región del blanco se puede actualizar de forma interactiva y simular la posición y volumen de las lesiones. Conclusiones. Los beneficios de esta metodología incluyen la mejora en la exactitud de la localización del primer blanco quirúrgico, disminución del número de trayectos con los electrodos y, por tanto, del tiempo de la cirugía, y la reducción de las posibles complicaciones quirúrgicas.

OBJETIVO: O objetivo do presente estudo foi verificar o efeito da abstinência do fumo nas respostas cardiovasculares ao exercício físico progressivo submáximo em mulheres sedentárias fumantes. MÉTODOS: A pressão arterial sistólica (PAS) e diastólica (PAD) e a freqüência cardíaca (FC) foram medidas de forma não invasiva em mulheres jovens não fumantes (MNF, n = 7) e fumantes (MF, n = 7), sem e com abstinência do fumo por 24 horas, em repouso, durante a realização do teste submáximo em bicicleta ergométrica e na recuperação. RESULTADOS: Em repouso, a PAD e a FC foram maiores nas MF (76 ± 1mmHg e 86 ± 5bpm) quando comparadas com as MNF (68 ± 2mmHg e 72 ± 2bpm). Após 24 horas sem o tabaco essas medidas foram normalizadas. Durante o exercício, a PAS e a FC aumentaram nos grupos estudados. A PAD foi maior nas MF (~15%) em relação às MNF em todos os estágios do exercício. Na situação de abstinência, a PAD aumentou somente no último estágio de exercício. Na recuperação tanto a PAD quanto a FC foram maiores nas MF, na situação basal e com abstinência de 24h, quando comparadas as MNF. CONCLUSÃO: Estes resultados demonstram que mulheres jovens fumantes apresentam prejuízo em parâmetros hemodinâmicos em repouso e em resposta ao exercício submáximo, os quais, podem ser em parte revertidos pela abstinência em curto prazo do uso do tabaco.

OBJECTIVE: The objective of the present study was to verify the effect of tobacco smoking abstinence on cardiovascular responses to progressive submaximal physical exercise in sedentary female smokers. METHODS: Systolic blood pressure (SBP), diastolic blood pressure (DBP) and heart rate (HR) were non-invasively measured in young non-smoking women (NSW, n = 7) and smoking women (SW, n = 7), with and without tobacco abstinence for 24 hours, at rest, during the accomplishment of a submaximal bicycle ergometric test and recovery period. RESULTS: At rest, DBP and HR were higher in the SW group (76 ± 1 mmHg and 86 ± 5 bpm) when compared to the NSW group (68 ± 2 mmHg and 72 ± 2 bpm). After 24 hours of no tobacco use, the groups presented similar values. During exercise, SBP and HR increased in the studied groups. DBP was higher in the SW group (~15%) in relation to the NSW group in all periods of exercise training. In the abstinence period, DBP only increased in the last load of exercise. During recovery period, in basal condition and 24h-abstinence, both DBP and HR were higher in the SW group when compared to the NSW group. CONCLUSION: These results show that young female smokers present harmful consequences in hemodynamic parameters at rest and in response to submaximal exercise. These findings can be partly reverted by short-term abstinence from tobacco use.

In this work, we employed the Density Functional Theory to determine thermodynamic properties of isotropic and nematic phases of liquid crystals, based on a "Convex Peg" model. The Helmholtz-free energy of the molecular system, a convex hard core within an encircling spherical square-well (SW) potential, is obtained from a second-order perturbation theory for SW nonspherical particles, combined with the Parsons decoupling approximation of the translational and rotational degrees of freedom, and a long-range approximation for the evaluation of the perturbation terms. The theory is applied to predict the phase diagram and isotropic-nematic transition of p-azoxyanisole (PAA), 4 -pentyl - 4' - cyanobiphenyl (5CB) and 4 - 4'- bis (heptiloxy) azoxybenzene (HOAOB). To do this, an estimation of the volume and k of a Liquid Crystal molecule was derived using IPCM calculations; the volume obtained is mapped into a hard ellipsoid revolution volume of a Convex Peg molecule. A very good agreement in the prediction of the thermodynamic properties is obtained when they are compared with experimental data.

En este trabajo utilizamos la teoría de los funcionales de la densidad para determinar las propiedades termodinámicas de las fases isótropa y nemática de los cristales líquidos, basados en el modelo Convex Peg. La energía libre de Helmholtz del sistema molecular, una coraza dura circunscrita por un potencial tipo pozo cuadrado esférico (SW), es obtenida de una teoría de perturbaciones a segundo orden para partículas no esféricas SW, combinadas con la aproximación de desacoplamiento de Parsons de los grados de libertad traslacionales y rotacionales, y una aproximación de largo alcance para la evaluación de los términos de perturbación. La teoría es aplicada para predecir el diagrama de fase y la transición isótropa-nemática del p-azoxianisol (PAA), 4 - pentyl - 4' - cyanobiphenyl (5CB) y el 4 - 4'- bis (heptiloxy) azoxybenzene (HOAOB). Para hacer esto fueron derivadas una estimación del volumen y k del cristal líquido utilizando calculos IPCM; el volumen obtenido es mapeado al volumen de un elipsoide de revolución rígido de una molécula Convex Peg. Un muy buen acuerdo es obtenido en la predicción de las propiedades termodinámicas cuando son comparadas con los datos experimentales.

Apesar do diagnóstico da anemia infecciosa e mais evidências recentes de infecção em campo (Brentano & Ottati, 1999), não havia até hoje dados disponíveis da prevalência do vírus da anemia das galinhas (CAV) no Brasil. Uma vez que o conhecimento da prevalência do vírus e da distribuição de anticorpos nos lotes de matrizes é essencial para o delineamento de estratégias de controle da doença, realizamos um levantamento em 5 Estados com produção comercial intensiva de linhas de corte, abrangendo lotes de aves com diferentes idades. De 2.355 soros testados por ELISA, 89% foram positivos, indicando a alta prevalência do CAV no Brasil, em todos os Estados testados. A análise do soro de aves das 6 até as 70 semanas de idade demonstrou que lotes de 6 a 18 semanas apresentam desuniformidade na imunidade ao CAV, caracterizada por títulos de anticorpos abaixo dos níveis considerados protetores e aves ainda negativas para o CAV. A desuniformidade nos títulos de anticorpos e a ausência dos mesmos são evidentes ainda, mas em menor proporção também até as 24 semanas, enquanto que apenas partir das 25 semanas há 100% de soroconversão, acompanhada de significativa redução da desuniformidade no título de anticorpos das matrizes para menos de 2,5% das aves. Esses resultados fornecem evidência de uma progressiva disseminação do vírus em matrizes de corte, mas com riscos da presença de aves ainda susceptíveis à transmissão vertical e inadequada transferência de imunidade passiva no início do período de postura, que podem culminar em surtos da doença na progênie.

Although the isolation and identification of CAV as well as other recent diagnosis of the virus in broiler flocks have provided evidence for chicken anemia virus, Brentano & Ottati (1999), the prevalence of CAV had not yet been determined in Brazil. Since the knowledge of the prevalence of the virus and the level of antibodies against CAV in breeders flocks provide key information for designing control measures against chicken infectious anemia, we conducted a serological survey in broiler breeders of different ages, in five States with intensive commercial broiler flock production. Of a total of 2,355 sera tested by a commercial ELISA assay, 89% were found positive for antibodies to CAV, indicating a high prevalence of the virus in Brazil, in all the surveyed states. The analysis of antibodies to CAV in 6 to 70 week-old breeders showed that flocks between 6 and 18 weeks of age have the highest number of seronegative and low antibody titer chickens, thus representing the age group with the most uneven level of immunity against CAV. Chickens with negative or low antibody titers were still detected until 24 weeks of age, whereas at 25 weeks there was a 100% seroconversion to CAV and a reduction to less than 2,5% in the number of chickens with low antibody titers. These results provide evidence for a gradual and progressive virus spread in broiler breeder flocks, with the occurrence of a small percentage of chickens with low antibody titers at beginning of lay and therefore susceptible to inadequate transfer of passive immunity and vertical transmission of CAV to their progeny.