Um tabuleiro de duas faces: o l��dico e o aleat��rio na fic����o cient��fica de Philip K. Dick

Embora apenas quatro t��tulos da obra de Philip K. Dick abordem o tema do acaso ��� Solar Lottery (escrito em 1954), The Man in the High Castle (1961), The Game Players of Titan (1963) e A Maze of Death (1968) ���, este surge contudo associado, e de forma bastante coerente, a outros, como a oposi����o humano/inumano ou a dial��ctica entre a percep����o e a realidade, que s��o mais comummente referidos como dominantes no autor. A estrat��gia seguida neste artigo consiste, ap��s uma sum��ria passagem pelas novelas acima referidas, na demonstra����o de como uma aparente dualidade no tratamento do acaso pode ser resolvida a partir do momento em que se assume uma perspectiva mais alargada do universo tem��tico de Philip K. Dick.

Ampicilina K em dose ��nica, por via oral, no tratamento da gonorr��ia

Foram tratados 70 pacientes do sexo masculino portadores de uretrite gonoc��cica aguda com 3,0 g de Ampicilina K por via oral, em dose ��nica. Em 87,1% dos casos houve desaparecimento da secre����o uretral; na grande maioria dos casos entre 24 e 72 horas. Considerados mais 3 casos em que houve persist��ncia da secre����o p��s tratamento, mas com aus��ncia de gonococos aos exames bacteriol��gicos (cura bacteriol��gica) o sucesso terap��utico pode ser elevado para 91,4%.

Biologia de Anopheles (Kerteszia) neivai H., D. & K., 1913 (Diptera: Culicidae) en la costa Pac��fica de Colombia: I. Fluctuaci��n de la poblaci��n larval y caracter��sticas de sus criaderos

En Charambir��, localidad del munic��pio de Istmina (Choc��) en la costa Pac��fica de Colombia, donde existe un problema de malaria end��mica, se estudi�� la fluctuaci��n de la poblaci��n larval y las caracter��sticas de los criaderos de Anopheles (Kerteszia) neivai, especie considerada como posible vectora de malaria en esa regi��n del pa��s. La vegetaci��n circundante fue dividida en tres estratos de acuerdo al grado de cobertura foliar. Se demarcaron cuadrantes de 100 m&#178 en cada estrato para el muestreo de plantas ep��fitas de la fam��lia Bromeliaceae, en las cuales se acumula agua que sirve como criadero para esta especie de anofelino. Se tomaron datos de temperatura, pH y volumen del agua contenida en cada bromelia. El mayor n��mero de larvas se detect�� en el estrato 1 (manglar) a una altitud inferior a 4 m, pero no se encontr�� evidencia significativa de estratificaci��n vertical de la poblaci��n larval de A. neivai hasta los 8 m. Se evidenci�� una correlaci��n lineal positiva entre el n��mero de larvas y el volumen de agua contenida en cada bromelia; por otra parte se observ�� tambi��n una correlaci��n directa entre la precipitaci��n mensual acumulada y la fluctuaci��n poblacional de esta especie. Los ��ndices larvales mas altos se observaron entre los meses de marzo a abril y de julio a agosto. La mortalidad larval fue alta en el primer estad��o (43,5%) y solo un 23,7% sobrevivi�� hasta el cuarto.

Biologia de Anopheles (Kerteszia) neivai H., D. & K., 1913 (Diptera: Culicidae) en la costa Pac��fica de Colombia: II. Fluctuaci��n de la poblaci��n adulta

En la localidad de Charambir��, situada en el munic��pio de Istmina (Choc��) en la costa Pac��fica de Colombia, se presenta un problema de malaria end��mica asociada con grandes poblaciones de mosquitos Anopheles del subg��nero Kerteszia (A. neivai). Estos se cr��an en las colecciones de agua formadas por plantas ep��fitas de la fam��lia Bromeliaceae, que son muy abundantes en los ��rboles de mangle. En esa localidad se estudiaron: fluctuaci��n poblacional y algunos aspectos ecol��gicos y etol��gicos de los adultos de esa especie de mosquito, con el objetivo de determinar su papel en la transmisi��n de malaria. Todos los mosquitos fueron colectados por cebos humanos. Los picos m��ximos de actividad ocurrieron en las horas crepusculares de la ma��ana y de la tarde (5:30 a 6:30 y 18:00 a 19:00 horas). En el per��odo nocturno la actividad intradomiciliar fue baja y no hubo ninguna durante el d��a. El estado gonadotr��fico de las hembras colectadas durante nos picos de actividad, mostr�� la existencia de dos poblaciones de mosquitos: una, en su mayor��a individuos j��venes que buscan su alimento en las horas de la tarde y la otra compuesta por individuos mas longevos, que buscan su alimento en la ma��ana. El estudio de la variaci��n estacional mostr�� que las poblaciones son bajas en los meses de poca precipitaci��n, pero a medida que aumenta el ��ndice pluviom��trico, aumenta el n��mero de mosquitos. Se discute la relaci��n que existe entre la presencia de los mosquitos y la prevalencia de malaria humana; se sugiere que A. neivai puede ser el responsable de la transmisi��n de malaria en la zona estudiada.

Biologia de Anopheles (Kerteszia) neivai H., D. & K., 1913 (Diptera: Culicidae) en la Costa Pac��fica de Colombia: III. Medidas de luminosidad y el comportamiento de picadura

El estudio del comportamiento de picadura de mosquitos capturados picando humanos en un ��rea despejada del poblado de Charambir��, Choc��, en la costa Pac��fica de Colombia, indico que cambios en la intensidad de la luz, influenciaban el in��cio y el fin de la actividad de vuelo de Anopheles (Kerteszia) neivai, especie con marcados h��bitos crepusculares. Esta especie est�� considerada como vectora de esa enfermedad, malaria, en la costa pac��fica colombiana.

Biolog��a de Anopheles (Kerteszia) neivai H., D. & K., 1913 (Diptera: Culicidae) en la Costa Pacifica de Colombia: IV - Estructura et��rea y transmisi��n de malaria

Con el fin de determinar la dinamica de transmisi��n de malaria en el poblado de Charambir�� (Choc��), Colombia, se estudi�� la estructura et��rea de Anopheles neivai (reconocido vector en la Costa Pac��fica) con base en su estado gonadotr��fico. Se recolectaron mosquitos intradomiciliarmente durante el crep��sculo vespertino con cebos humanos y aspiradores bucales. Los mosquitos recolectados se mantuvieron en cajas cil��ndricas de cart��n con papel humedecido y dispensadores alimenticios hasta su disecci��n al d��a siguiente. De los 200 mosquitos disecados entre septiembre y octubre de 1986,68 (34%) presentaban huellas de menos de tres oviposturas y los restantes (66%) hab��an efectuado al menos tres oviposturas. La diferencia entre el primer grupo considerado como mosquitos "no infectivos" y el segundo considerado como los "potencialmente infectivos" fue altamente significativa (X�� = 10,68; P = 0,001). El 1,5% de A. neivai estudiados presentaban huellas correspondientes a 10 oviposturas mostrando una marcada longevidad y m��ltiples alimentaciones sangu��neas. Los resultados sugieren que existe un alto riesgo de contraer malaria en Charambir�� durante el crep��sculo vespertino.

Improving a Cluster Based Directional Channel Model in Realistic Macro-Cell Environment

In this paper a realistic directional channel model that is an extension of the COST 273 channel model is presented. The model uses a cluster of scatterers and visibility region generation based strategy with increased realism, due to the introduction of terrain and clutter information. New approaches for path-loss prediction and line of sight modeling are considered, affecting the cluster path gain model implementation. The new model was implemented using terrain, clutter, street and user mobility information for the city of Lisbon, Portugal. Some of the model's outputs are presented, mainly path loss and small/large-scale fading statistics.

Phototransistor with nanocrystalline Si/amorphous Si bilayer channel

We report a field-effect phototransistor with a channel comprising a thin nanocrystalline silicon transport layer and a thicker hydrogenated amorphous silicon absorption layer. The semiconductor and dielectric layers were deposited by radio-frequency plasma enhanced chemical vapor deposition. The phototransistor with channel length of 24 microns and photosensitive area of 1.4 mm(2) shows an off-current of about 1 pA, and high photoconductive gain in the subthreshold region. Measurements of the quantum efficiency at different incident light intensities and biasing conditions, along with spectral-response characteristics, and threshold voltage stability characterization demonstrate the feasibility of the phototransistor for low light level detection.

Chaos and crises in a model for cooperative hunting: A symbolic dynamics approach

In this work we investigate the population dynamics of cooperative hunting extending the McCann and Yodzis model for a three-species food chain system with a predator, a prey, and a resource species. The new model considers that a given fraction sigma of predators cooperates in prey's hunting, while the rest of the population 1-sigma hunts without cooperation. We use the theory of symbolic dynamics to study the topological entropy and the parameter space ordering of the kneading sequences associated with one-dimensional maps that reproduce significant aspects of the dynamics of the species under several degrees of cooperative hunting. Our model also allows us to investigate the so-called deterministic extinction via chaotic crisis and transient chaos in the framework of cooperative hunting. The symbolic sequences allow us to identify a critical boundary in the parameter spaces (K, C-0) and (K, sigma) which separates two scenarios: (i) all-species coexistence and (ii) predator's extinction via chaotic crisis. We show that the crisis value of the carrying capacity K-c decreases at increasing sigma, indicating that predator's populations with high degree of cooperative hunting are more sensitive to the chaotic crises. We also show that the control method of Dhamala and Lai [Phys. Rev. E 59, 1646 (1999)] can sustain the chaotic behavior after the crisis for systems with cooperative hunting. We finally analyze and quantify the inner structure of the target regions obtained with this control method for wider parameter values beyond the crisis, showing a power law dependence of the extinction transients on such critical parameters.

Enthalpies of Solution of 1-Butyl-3-methylimidazolium Tetrafluoroborate in 15 Solvents at 298.15 K

Enthalpies of solution of 1-butyl-3-methylimidazolium tetra fluoroborate, [BMIm]BF4, are reported at 298.15 K in a set of 15 hydrogen bond donor and hydrogen bond acceptor solvents, chosen by their diversity, namely, water, methanol, ethanol, 1,2-ethanediol, 2-choroethanol, 2-methoxyethanol, formamide, propylene carbonate, nitromethane, acetonitrile, dimethyl sulfoxide, acetone, N,N-dimethylformamide, N,N-dimethylacetamide, and aniline. These values are shown to be largely independent of [BMIm]BF4 concentration. The obtained enthalpies of solution vary from very endothermic to quite exothermic, thus showing a very high sensitivity of the enthalpies of solution of [BMIm]BF4 to solvent properties. Solvent effects on the solution process of this IL are analyzed by a quantitative structure-property relationship methodology, using the TAKA equation and a modified equation, which significantly improves the model's predictive ability. The observed differences in the enthalpies of solution are rationalized in terms of the solvent properties found to be relevant, that is, pi* and E-T(N).

Variation of magnetic properties in sedimentary rocks hosting the Foum Zguid dyke (southern Morocco): Combined effects of re-crystallization and Fe-metasomatism

The effects of dyke intrusion on the magnetic properties of host sedimentary rocks are still poorly understood. Therefore, we have evaluated bulk magnetic parameters of standard palaeomagnetic samples collected along several sections across the sediments hosting the Foum Zguid dyke in southern Morocco. The study has been completed with the evaluation of the magnetic fabric after laboratory application of sequential heating experiments. The present study shows that: (1) close to Fourn Zguid dykes, the variations of the bulk magnetic parameters and of the magnetic fabric is strongly related with re-crystallization and Fe-metasomatism intensity. (2) The thermal experiments on AMS of samples collected farther from the dyke and, thus, less affected by heating during dyke emplacement, indicate that 300-400 degrees C is the minimum experimental temperature necessary to trigger appreciable transformations of the pre-existing magnetic fabrics. For temperatures higher than ca. 580 degrees C, the magnetic fabric transformations are fully realized, with complete transposition of the initial fabric to a fabric similar to that of samples collected close to the dyke. Therefore, measured variations of the magnetic fabric can be used to evaluate re-crystallization temperatures experienced by the host sedimentary rock during dyke emplacement. The distinct magnetic behaviour observed along the cross-sections strongly suggests that samples collected farther from the dyke margins did not experience thermal episodes with temperatures higher than 300 degrees C after dyke emplacement. (3) AMS data shows a gradual variation of the magnetic fabric with distance from the dyke margin, from sub-horizontal K-3 away from the dyke to vertical K3 close to the dyke. Experimental heating shows that heat alone can be responsible for this strong variation. Therefore, such orientation changes should not be unequivocally interpreted as the result of a stress field (resulting from the emplacement of the dyke, for instance). (4) Magnetic studies prove to be a very sensitive tool to assess rock magnetic transformations, thermally and chemically induced by dyke intrusion in hosting sediments.

Strength, muscle quality and functional capacity in liver transplanted familial amyloidotic polineuropathy patients

Liver transplantation is the unique treatment for several end stage diseases. Familial Amiloidotic Polineuropathy (FAP) is a neurodegenerative disease related with systemic deposition of amyloidal fibre mainly on peripheral nervous system, clinically translated by an autonomous sensitive-motor neuropathy with severe functional limitations in some cases. The unique treatment for FAP disease is a liver transplant with a very aggressive medication to muscle metabolism and force production. To our knowledge there are no quantitative characterizations of body composition, strength or functional capacity in this population. The purpose of this study was to compare levels of specific strength (isometric strength adjusted by lean mass or muscle quality) and functional capacity (meters in 6 minutes walk test) between FAP patients after a liver transplant (4.1��2 months after transplant surgery) (FAPT) and a healthy group (HG).

Classifica����o sem��ntica de imagens com k-NN e RN

Um dos maiores desafios tecnol��gicos no presente �� o de se conseguir gerar e manter, de uma maneira eficiente e consistente, uma base de dados de objectos multim��dia, em particular, de imagens. A necessidade de desenvolver m��todos de pesquisa autom��ticos baseados no conte��do sem��ntico das imagens tornou-se de m��xima import��ncia. MPEG-7 �� um standard que descreve o contudo dos dados multim��dia que suportam estes requisitos operacionais. Adiciona um conjunto de descritores audiovisuais de baixo n��vel. O histograma �� a caracter��stica mais utilizada para representar as caracter��sticas globais de uma imagem. Neste trabalho �� usado o ���Edge Histogram Descriptor��� (EHD), que resulta numa representa����o de baixo n��vel que permite a computa����o da similaridade entre imagens. Neste trabalho, �� obtida uma caracteriza����o sem��ntica da imagem baseada neste descritor usando dois m��todos da classifica����o: o algoritmo k Nearest Neighbors (k-NN) e uma Rede Neuronal (RN) de retro propaga����o. No algoritmo k-NN �� usada a dist��ncia Euclidiana entre os descritores de duas imagens para calcular a similaridade entre imagens diferentes. A RN requer um processo de aprendizagem pr��via, que inclui responder correctamente ��s amostras do treino e ��s amostras de teste. No fim deste trabalho, ser�� apresentado um estudo sobre os resultados dos dois m��todos da classifica����o.

Symbolic dynamics and renormalization of non-autonomous k periodic dynamical systems

The purpose of this paper was to introduce the symbolic formalism based on kneading theory, which allows us to study the renormalization of non-autonomous periodic dynamical systems.

Detection of Change in Fluorescence Between Reactive Cyan and the Yellow Fluorophores Using a-SiC:H Multilayer Transducers

The transducer consists of a semiconductor device based on two stacked -i-n heterostructures that were designed to detect the emissions of the fluorescence resonance energy transfer between fluorophores in the cyan (470 nm) and yellow (588 nm) range of the spectrum. This research represents a preliminary study on the use of such wavelength-sensitive devices as photodetectors for this kind of application. The device was characterized through optoelectronic measurements concerning spectral response measurements under different electrical and optical biasing conditions. To simulate the fluorescence resonance energy transfer (FRET) pairs, a chromatic time-dependent combination of cyan and yellow wavelengths was applied to the device. The generated photocurrent was measured under reverse and forward bias to read out the output photocurrent signal. A different wavelength-biasing light was also superimposed. Results show that under reverse bias, the photocurrent signal presents four separate levels, each one assigned to the different wavelength combinations of the FRET pairs. If a blue background is superimposed, the yellow channel is enhanced and the cyan suppressed, while under red irradiation, the opposite behavior occurs. So, under suitable biasing light, the transducer is able to detect separately the cyan and yellow fluorescence pairs. An electrical model, supported by a numerical simulation, supports the transduction mechanism of the device.