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Conducting Experiments (conducting + experiment)
Selected AbstractsAntixenosis phloem-based resistance to aphids: is it the rule?ECOLOGICAL ENTOMOLOGY, Issue 4 2010VINCENT LE ROUX 1. The concept of plant defence syndrome states that plant species growing in similar biotic or abiotic constraints should have convergent defensive traits. This article is a first step to test the prediction of this concept, by conducting experiments on wild Solanum species (or accessions) that originated from the Andes. The nature and the tissue localisation of the resistance of five wild Solanum species known to be resistant against the aphids Myzus persicae and Macrosiphum euphorbiae were determined by olfactometry and electrical penetration graph experiments. 2. Volatile organic compounds may contribute to wild Solanum resistance, depending on Solanum accessions and aphid species. Volatiles of S. bukasovii and S. stoloniferum PI 275248 were not attractive to M. persicae, whereas S. bukasovii was repulsive to M. euphorbiae. In contrast, volatiles of S. stoloniferum PI 275248 were attractive for M. euphorbiae. 3. Some wild Solanum species presented a generalised resistance in all plant tissues, so as for S. bukasovii and S. stoloniferum PI 275248 against M. persicae. However, except for S. bukasovii which was susceptible to M. euphorbiae, all tested Solanum species presented a phloem-based antixenosis resistance against the two aphid species. 4. A review of articles focused on the nature of resistance of wild Solanum species against aphids corroborated with our results, i.e. a phloem-based antixenosis resistance against aphids is the rule concerning the system aphids,wild Solanum species. [source] Semantic Differences in Sifaka (Propithecus verreauxi) Alarm Calls: A Reflection of Genetic or Cultural Variants?ETHOLOGY, Issue 9 2006Claudia Fichtel In this study, we compared the usage of alarm calls and anti-predator strategies between a captive and a wild lemur population. The wild lemur population was studied earlier in Western Madagascar (Fichtel & Kappeler 2002). The captive population was studied in outdoor enclosures of the Duke University Primate Center. Alarm calls and anti-predator behavior were elicited by conducting experiments with both vocal and visual dummies. We scored the subjects' immediate behavioral responses, including alarm calls, from video recordings made during the experiments. In principle, both populations have a mixed alarm call system with functionally referential alarm calls for aerial predators and general alarm calls for terrestrial and aerial predators and for situations associated with high arousal, such as group encounters. Although wild and captive sifakas exhibit the same alarm call system and use the same alarm call types, we discovered striking differences in the usage and perception of some of the alarm calls. We argue that these differences indicate either an evolutionary drift in the meaning of these calls or reflect cultural variation. The latter possibility is consistent with our understanding of the ontogeny of call usage and comprehension. [source] Expression and identification of a new splice variant of neuroglycan C, a transmembrane chondroitin sulfate proteoglycan, in the human brainJOURNAL OF NEUROSCIENCE RESEARCH, Issue 1 2006Sachiko Aono Abstract Neuroglycan C (NGC) is a transmembrane chondroitin sulfate proteoglycan with an EGF module. We studied the expression of NGC in the human brain, mainly in the hippocampus, and confirmed some observations by conducting experiments using rat brain. In humans, NGC mRNA was expressed exclusively in the brain, especially in the immature brain. The telencephalon, including the hippocampus and neocortex, showed strong mRNA expression. NGC was immunolocalized to neuropils in the hippocampus and neocortex of the adult rat. RT-PCR experiments showed that four splice variants (NGC-I, -II, -III, and -IV) were expressed in the adult human hippocampus. By Western blotting, the expression as proteins of all splice variants except NGC-II was confirmed in the adult rat hippocampus. NGC-IV, which was first found in the present study, had the shortest cytoplasmic domain among the four variants. NGC-IV mRNA was expressed by neurons, but not by astrocytes, in culture prepared from the fetal rat hippocampus, suggesting that NGC-IV plays a role specific to neurons. In addition, the human NGC gene, which is registered as CSPG5, comprised six exons and was approximately 19 kb in size. In exon 2, a single nucleotide polymorphism resulting in Val188Gly in the NGC ectodomain was observed. © 2005 Wiley-Liss, Inc. [source] Microwave and conventional curing of thick-section thermoset composite laminates: Experiment and simulationPOLYMER COMPOSITES, Issue 2 2001Erik T. Thostenson In conventional processing, thermal gradients cause differential curing of thick laminates and undesirable outside-in solidification. To reduce thermal gradients, thick laminates are processed at lower cure temperatures and heated with slow heating rates, resulting in excessive cure times. Microwaves can transmit energy volumetrically and instantaneously through direct interaction of materials with applied electromagnetic fields. The more efficient energy transfer of microwaves can alleviate the problems associated with differential curing, and the preferred inside-out solidification can be obtained. In this work, both microwave curing and thermal curing of 24.5 mm (1 inch) thick-section glass/epoxy laminates are investigated through the development of a numerical process simulation and conducting experiments in processing thick laminates in a conventional autoclave and a microwave furnace. Outside-in curing of the autoclave-processed laminate resulted in visible matrix cracks, while cracks were not visible in the microwave-processed laminate. Both numerical and experimental results show that volumetric heating due to microwaves promotes an inside-out cure and can dramatically reduce the overall processing time. [source] Mathematical model for mixing index in gas,solid fluidized bed: an analysisASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 4 2010Abanti Sahoo Abstract An available theoretical model for mixing index in gas-solid fluidized bed has been analyzed for further modification and improvement. Assumption of 50% bed material moving in the upward direction and rest 50% in the downward direction considered for the above model (the counter-flow circulation model) has been analyzed for optimum result. A computer program was run for different bed conditions by varying operating parameters, namely, the mixture composition, fractions of bed materials, minimum fluidization velocity of the jetsam particles and that of the bed materials (i.e. mixture of the jetsam and the flotsam particles). The developed model was solved by finite difference (central differencing). Fraction of the bed material moving in the upward direction was varied from 0 to 100% and the minimum fluidization velocity was varied within the Umf of the flotsam to that of the jetsam particles (i.e. 0.465,1.0335 m/s). Optimum fraction of bed materials with respect to its distribution (as per the earlier proposed model) in the upward and downward streams during the fluidization process was found to be 20 and 80%, respectively. The modified model was validated by conducting experiments on fluidization and studying the mixing characteristics of regular homogeneous materials (sago) in a 15 × 100 cm cylindrical column. Fairly good agreement was observed between the values of mixing index obtained from the proposed modified model and the experimental observations. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd. [source] Different Stimuli Reduce Attraction to Pollinators in Male and Female Figs in the Dioecious Fig Ficus hispidaBIOTROPICA, Issue 6 2009Hao-Yuan Hu ABSTRACT Fig trees (Ficus) and their obligate pollinating wasps (Hymenoptera, Chalcidoidea, Agaonidae) are a classic example of a coevolved mutualism. Pollinating wasps are attracted to figs only when figs are receptive. It has been shown that figs will lose their attraction to pollinators sooner in monoecious and male dioecious figs when multiple pollinators have entered the enclosed inflorescence. However, little is known about the nature of the stimulus inducing the loss of attraction. By conducting experiments on the functionally dioecious fig, Ficus hispida, we show that (1) different stimuli induce the loss of attraction in each sex, pollination in female figs, and oviposition in male figs; and (2) foundress number affects the loss of attraction in both sexes only when the prerequisites (i.e., pollination in female figs and oviposition in male figs) have been satisfied. In general, the more foundresses that enter, the earlier the fig will lose its receptivity. We argue that the stimuli in male and female figs are adaptations to the fulfillment of its respective reproduction. [source] | ||||||||||