Alex Guillen

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Drosophila subobscura has recently colonized the American continent and is an excellent model for studying evolution in action. Previous analyses have shown that these colonizing populations have significant latitudinal clines for the frequencies of some chromosomal arrangements that parallel those clines found in the Old World. These results strongly(More)
Chromosome variability within three populations ofScilla autumnalis was analysed. Among a total of 167 individuals we have detected one triploid structural heterozygote, 26 B-containing (with two different B-types), 11 structural variants (in the fifth chromosome pair), and one asynaptic. The possible relation between both types of chromosome variability(More)
We assessed the differences in appetitive responses to visual stimuli by three species of praying mantis (Insecta: Mantodea), Tenodera aridifolia sinensis, Mantis religiosa, and Cilnia humeralis. Tethered, adult females watched computer generated stimuli (erratically moving disks or linearly moving rectangles) that varied along predetermined parameters.(More)
A novel modified India ink technique for the diagnosis of Cryptococcus neoformans in cerebrospinal fluid specimens is described. It employs 2% chromium mercury and India ink. This technique allows a clear identification of some external and internal structures of the organism. Three layers from the outer capsule that have previously been discerned only by(More)
Path-coefficient analysis based on an ontogenetic model was used to study the relationships between tuber yield and yield components as influenced by cultivar and nitrogen fertilization. Four experiments were carried out from 1987 to 1989 in Granada, southern Spain. Two of these experiments used six potato cultivars with a single N rate, while the other two(More)
The authors study shear flow in hybrid-aligned nematic cells under the action of an applied electric field by solving numerically a hydrodynamic model. The authors apply this model to a flow-aligning nematic liquid crystal (4'-n-pentyl-4-cyanobiphenyl) and obtain the director's configuration and the velocity profile at the stationary state. The authors(More)
A popular method for generating micron-sized aerosols is to submerge ultrasonic (ω~MHz) piezoelectric oscillators in a water bath. The submerged oscillator atomizes the fluid, creating droplets with radii proportional to the wavelength of the standing wave at the fluid surface. Classical theory for the Faraday instability predicts a parametric instability(More)
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