Sex differences in susceptibility to the Poggendorff illusion.

This study presents experimental results indicating that there are sex differences in the susceptibility to a geometric optical illusion. Participants (57 male and 39 female undergraduate students) performed 3 trials on a test involving the Poggendorff illusion. Analysis indicated that the magnitude of the illusion diminished significantly with each trial and that the percent perceived error was significantly larger for women than for men.

Neuroendocrine epithelial cells in the broncho-parabronchial transition of embryonic, immature and mature quail (Coturnix coturnix).

The main objective of this integrated light microscopic, transmission and scanning electron microscopic study was to describe in greater detail the structural pattern and developmental stages of pulmonary neuroendocrine epithelial cells (PNECs) in the broncho-parabronchial transition (BPT) of both developing and mature quail. In mature quail the BPT appeared as a diaphragm opening into the parabronchial vestibulum. Perpendicular sections revealed two bilayered crest-like entrance folds invested by a uniform population of granular cells with lamellar bodies and a brush border of blunt microvilli.

Nutrient stress, host plant quality and herbivore performance of a leaf-mining fly on grass.

Environmental stresses affect plant growth and performance in nature. Host plant quality in turn affects herbivore performance and population dynamics. In view of these interactions, two major hypotheses were formulated.

Integrated condition indices as a measure of whole effluent toxicity in zebrafish (Danio rerio).

Toxic exposure of organisms interferes with organismal integrity at the biochemical level and ultimately gives rise to effects at the individual level. These effects may result in reductions in ecologically relevant characteristics such as growth, reproduction, and survival. A chronic toxicity test with zebrafish (Danio rerio) was conducted where fish were exposed to 50, 75, and 100% effluent for 28 d under flow-through conditions.

Distribution and role of Na(+)/K(+) ATPase in endocardial endothelium.

Objective: In mammalian cardiomyocytes, alpha isoforms of Na(+)/K(+) ATPase have specific localisation and function, but their role in endocardial endothelium is unknown.

Methods: Different alpha isoforms in endocardial endothelium and cardiomyocytes of rabbit were investigated by measuring contractile parameters of papillary muscles, by RT-PCR, by Western blots and by immunocytochemistry.

Results: Inhibition of Na(+)/K(+) ATPase by decreasing external K(+) from 5.

Functional implications of extensive new data on the innervation of pulmonary neuroepithelial bodies.

Pulmonary neuroepithelial bodies (NEBs) are innervated organoid groups of neuroendocrine cells, present in the epithelial lining of intrapulmonary airways of man and all air-breathing vertebrates studied so far. NEBs receive a vagal nodose sensory innervation that is considered by other authors as their main, if not their only innervation, although apparently not needed for the normal development and maintenance of NEBs. In the present study of NEBs in the developing rat lung (gestational day 16 - adult), immunoreactivity (IR) for calcitonin gene-related peptide (CGRP; a marker for NEBs), protein gene product 9.

Esterase variation in the periwinkle Littorina littorea, along the western and eastern Scheldt estuarium.

Variation in esterase expression (EST) has been investigated in 360 specimens of the periwinkle Littorina littorea collected at nine sites along the polluted western Scheldt and the relatively clean eastern Scheldt estuary. Mean number of EST bands differed among the sites, while a Dice similarity based multi-dimensional scaling along with a minimum spanning tree procedure, revealed an estuary based structuring, clustering the most polluted and least saline like sites together. The underlying factors and mechanisms (i.

Intersex and sterility in the periwinkle Littorina littorea (Mollusca: Gastropoda) along the Western Scheldt estuary, The Netherlands.

In this study we present the results of an intersex survey of Littorina littorea along the heavily polluted Western Scheldt estuary (the Netherlands), and record for the first time the intersex phenomenon in L. littorea from Dutch waters. Intersex differed significantly between localities and was the highest in the vicinity of the harbours of Antwerp and Vlissingen, as reflected by the I

Effect of temperature on the uptake of waterborne strontium in the common carp, Cyprinus carpio (L.).

The effect of temperature on the uptake kinetics of strontium (Sr) in the common carp (Cyprinus carpio) was studied in vivo, exposing pre-acclimated fish to a wide range of Sr concentrations in water (Sr(total)=0.2-10,000 microM; Ca(total)=348 microM) at 10, 20, 25 and 30 degrees C. Sr uptake rates were determined in the whole body, gills and blood of the fish after an exposure period of 3 h and were analyzed as a function of the free-ion activity of Sr and Ca in water.

Effect of middle ear components on eardrum quasi-static deformation.

Eardrum deformation induced by quasi-static middle ear pressure was studied at progressive stages of dissection of gerbil temporal bones. With our high resolution moiré interferometer we recorded the shape and deformation of the eardrum along a line perpendicular to the manubrium and through the umbo, at different middle ear pressures. The deformation was measured from the medial side, after serially removing the cochlea, removing the stapes, cutting the tensor tympani, exposing the incudo-mallear joint, and cutting the anterior bony process which connects the malleus to the tympanic bone.

Lateral asymmetries in attentional priming during a semantic and a visuospatial task.

This study tests the hypothesis that lateral cueing of attention activates the contralateral hemisphere and also that performance on a semantic and a visuospatial task will differentially be affected depending on the visual field (right or left) to which attention was drawn. In an experimental setting, 68 subjects performed both a semantic and a visuospatial discriminating task, whereby visual priming signals unbeknownst were presented to either the left or the right visual field. For the semantic task (which is believed to engage primarily the left hemisphere) priming signals enhanced performance more when they were presented to the right visual field.

Optimization of adult performance determines host choice in a grass miner.

Models and empirical studies on host selection in plant-insect, algae-amphipod, host-parasite and prey-predator systems assume that oviposition preference is determined by the quality of the oviposition site for offspring development. According to the oviposition-preference-offspring-performance hypothesis, oviposition-preference hierarchy should correspond to host suitability for offspring development because females maximize their fitness by optimizing offspring performance. We show, we believe for the first time, that adult feeding site and related adult performance may explain most of the variation in adult feeding and oviposition site selection of an oligophagous grass miner, Chromatomyia nigra (Diptera).

Morphological and metabolic changes in common carp, Cyprinus carpio, during short-term copper exposure: interactions between Cu2+ and plasma cortisol elevation.

The effects of increased endogenous cortisol levels were compared with those of sublethal copper exposure in the freshwater common carp, Cyprinus carpio. Fish were exposed to either increased levels of endogenous cortisol (200 ng/ml) or sublethal copper (1.9 microM) alone or were pretreated by elevating plasma cortisol levels prior to copper exposure to assess whether interactions between both treatments occurred.

A mechanistic model for the uptake of waterborne strontium in the common carp (Cyprinus carpio L.).

The release of radioactive strontium to the environment is of concern due to the strong accumulation of this calcium resembling element in the bone and other tissues. To predict the effects of changes in environmental conditions on the uptake of Sr2+ and Ca2+ by freshwater fish, a Michaelis-Menten type model is introduced that accounts for the effects of chemical speciation, hydrogen ion activity, and metal ion competition. The uptake kinetics were characterized in vivo from short-term exposure experiments using the common carp (Cyprinus carpio) as the model organism.

Heavy metal levels in the sediments of four Dar es Salaam mangroves. Accumulation in, and effect on the morphology of the periwinkle, Littoraria scabra (Mollusca: Gastropoda).

Heavy metals were determined in the soft tissue and shells of the littorinid, Littoraria scabra, and in the sediments of four mangrove areas along the Dar es Salaam coastline where L. scabra was collected. Several metals accumulate, preferentially in the animals' soft body parts, but do not seem to affect the shell morphology of this species.

Food stress and predator-induced stress shape developmental performance in a damselfly.

I studied effects of stress factors like food shortage, non-lethal predator presence and autotomy on survival and larval performance (growth rate, development rate and developmental stability) of larvae of the damselfly Lestes sponsa. In a laboratory experiment, larvae were raised during their last two instars at two food levels (high or low) crossed with two levels of autotomy (caudal lamellae present or absent). These treatments were nested within three levels of predation risk (Aeshna cyanea absent, Chironomus-fed caged Aeshna or Lestes-fed caged Aeshna).

Excitatory synaptic inputs on myenteric Dogiel type II neurones of the pig ileum.

The synaptic input on myenteric Dogiel type II neurones (n = 63) obtained from the ileum of 17 pigs was studied by intracellular recording. In 77% of the neurones, electrical stimulation of a fibre tract evoked fast excitatory postsynaptic potentials (fEPSPs) with an amplitude of 6 +/- 5 mV (mean +/- S.D.

Is there a geographical pattern in the breeding system of a complex of hermaphroditic slugs (Mollusca: Gastropoda: Carinarion)?

Allozyme analyses of the hermaphroditic slugs Arion (Carinarion) fasciatus, A. (C.) circumscriptus and A.

Dynamics of (Cd,Zn)-metallothioneins in gills, liver and kidney of common carp Cyprinus carpio during cadmium exposure.

Cadmium concentrations, (Cd,Zn)-metallothionein (MT) concentrations, MT synthesis and the relative amounts of cadmium bound to (Cd,Zn)-MTs were determined in gills, liver and kidney of common carp Cyprinus carpio exposed to 0, 0.5 microM (0.06 mg.

Stress responses and changes in protein metabolism in carp Cyprinus carpio during cadmium exposure.

Stress responses and changes in protein metabolism were studied in common carp Cyprinus carpio exposed to 0, 0.8, 4, and 20 microM cadmium (Cd) over a 29-day period. Blood and other tissue samples were taken after 4 and 29 days of exposure.

Cadmium-binding to transferrin in the plasma of the common carp Cyprinus carpio.

In this study, it was investigated by autoradiography with radioactive cadmium after Western blotting of two-dimensional electrophoresis gels, to which proteins cadmium is mainly bound in plasma of common carp Cyprinus carpio. The obtained results demonstrate that in carp plasma, cadmium is primarily bound to two high molecular weight proteins. Relative small amounts are bound to a protein with M(r) approximately 60000.

Bioavailability of Cd to the common carp, Cyprinus carpio, in the presence of humic acid.

The uptake of cadmium by the common carp, Cyprinus carpio, was studied in chemically defined freshwater in the absence and presence of commercial humic acid. This was done to evaluate whether the cadmium uptake by carp in the presence of humic acid was related to the ambient Cd2+ -ion activity or whether the complexed metal also contributed to the uptake. Uptake of Cd during a 3-h period of exposure was used as a measure of the biological availability of the metal.

Accumulation of metals in the tissues of three spined stickelback (Gasterosteus aculeatus) from natural fresh waters.

Three spined sticklebacks (Gasterosteus aculeatus) were sampled from five different watercourses in Flanders (Belgium). Concentrations of cadmium, lead, copper, and zinc were measured in water, sediment, food, and fish tissues. Considered as food was the taxonomic groups of macroinvertebrates predominately present in the stomach of the sticklebacks at the different sites.

Microstructure of Cu(x)Mo6S8 Chevrel phase thin films on R-plane sapphire.

Cu(x)Mo6S8 Chevrel phase thin films epitaxially grown on R-plane sapphire substrates have been studied using field emission scanning electron microscopy (FE-SEM) and high-resolution transmission electron microscopy (HREM). For samples grown in optimal conditions, the SEM images evidence oriented grains of about 100 nm average size; the HREM images of cross-section samples allow to deduce the local epitaxial relations between the substrates and films. HREM also evidences two grain families, previously deduced from X-ray and reflection high-energy electron diffraction studies.

Cluster diversity and entropy on the percolation model: the lattice animal identification algorithm.

We present an algorithm to identify and count different lattice animals (LA's) in the site-percolation model. This algorithm allows a definition of clusters based on the distinction of cluster shapes, in contrast with the well-known Hoshen-Kopelman algorithm, in which the clusters are differentiated by their sizes. It consists in coding each unit cell of a cluster according to the nearest neighbors (NN) and ordering the codes in a proper sequence.