Stien, D., & Gastaldi, S. (2004). Design of polyaromatic hydrocarbon-supported tin reagents: A new family of tin reagents easily removable from reaction mixtures. J. Org. Chem., 69(13), 4464–4470.
Abstract: We report in this paper the preparation and use of stannanes 11, 12a, and 12b, compounds whose 3-pyrenylpropyl side chain affinity for activated carbon simplifies tin removal and product isolation. Our pyrene-supported reagents can be used for radical reductions and cyclizations (11), radical and cationic allylations (12a), and Stille couplings (12b) in much the same way as tributyltin derivatives.
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Degen, B., & Roubilk, D. W. (2004). Effects of animal pollination on pollen dispersal, selfing, and effective population size of tropical trees: A simulation study. Biotropica, 36(2), 165–179.
Abstract: Animals, especially insects, are principal pollen vectors of tropical trees and have behavior patterns that affect gene dispersal. Here, we explore complex pollination systems using a new simulation model Eco-Gene and considering, among other factors, flowering synchrony. spatial distribution of trees, degree of selfing, population densities, pollinator flight distances, pollen deposition, and pollinator response to floral display size. Sensitivity analyses using two contrasting tree data sets (Jacaranda copaia and Dipteryx odorata) determined the importance of each parameter on three response variables: the proportion of seeds from self-pollination, effective population size, and pollen dispersal. Spatial considerations and attractiveness of floral displays were prominent features determining the population genetic result of pollinators, and some biological implications of the results are discussed.
Keywords: Amazon; bees; Brazil; Dipteryx; Jacaranda; model; pollination; sensitivity analysis; trees
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Le Guen, V., Rodier-Goud, M., Troispoux, V., Xiong, T. C., Brottier, P., Billot, C., et al. (2004). Characterization of polymorphic microsatellite markers for Microcyclus ulei, causal, agent of South American leaf blight of rubber trees. Mol. Ecol. Notes, 4(1), 122–124.
Abstract: South American leaf blight caused by the ascomycete Microcyclus Wei is the most harmful disease of the rubber tree in Latin America and a potential threat to Asiatic and African natural rubber production. Until now, the variability of this fungus was assessed through observation of pathogenicity of isolates on a range of rubber tree clones with known resistance reactions. The present study describes the process used to design 11 microsatellite markers and evaluates their usefulness in detecting genetic polymorphism. Nine of these markers were polymorphic among six isolates from Brazil (with two to three alleles per locus) and five markers were polymorphic among four isolates from French Guiana (with two to four alleles per locus).
Keywords: Hevea brasiliensis; Microcyclus ulei; microsatellite markers; phytopathogenic fungi; South American leaf blight
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Gond, V., Bartholome, E., Ouattara, F., Nonguierma, A., & Bado, L. (2004). Monitoring and mapping of waters and wetlands in arid regions using the SPOT-4 VEGETATION imaging system. Int. J. Remote Sens., 25(5), 987–1004.
Abstract: Monitoring the state of small waterbodies and wetlands is very useful in dry regions, because their existence is entirely controlled by the rhythm of local rainfall. On VEGETATION image colour composites, waterbodies and marshy vegetation show up clearly. Yet simple image classification does not yield sufficiently good results because 'spectral signatures' vary significantly together with the ecological conditions of these surfaces. A robust contextual procedure taking into account local contrast was successfully developed and tested. A systematic validation was carried out and a map of waterbodies and wetlands was produced for Burkina Faso and neighbouring regions.
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Scotti-Saintagne, C., Bodenes, C., Barreneche, T., Pot, D., Plomion, C., & Kremer, A. (2004). Distribution of genomic regions differentiating oak species assessed by QTL detection. Heredity, 92(1), 20–30.
Abstract: Pedunculate oak and sessile oak are two sympatric inter-fertile species that exhibit leaf morphological differences. We aimed to detect quantitative trait loci (QTLs) of these traits in order to locate genomic regions involved in species differentiation. A total of 15 leaf morphological traits were assessed in a mixed forest stand composed of Quercus petraea and Q. robur and in a full-sib pedigree of Q. robur. The progeny of the full-sib family were vegetatively propagated in two successive experiments comprising 174 and 216 sibs, and assessments were made on two leaves collected on each of the 1080 and 1530 cuttings corresponding to the two experiments. Traits that exhibited strong species differences in the mixed stand tended also to have higher repeatability values in the mapping population, thus indicating higher genetic control. A genetic map was constructed for QTL detection. Composite interval mapping with the one QTL model was used for QTL detection. From one to three QTLs were detected for 13 traits. In-depth analysis of the QTLs, controlling the five morphological traits that exhibited the highest interspecific differences in the mixed stand, indicated that they were distributed on six linkage groups, with two clusters comprising QTLs of at least two discriminant traits. These results were reinforced when error 1 for QTL detection was set at 5% at the chromosome level, as up to nine clusters could be identified. In conclusion, traits involved in interspecific differentiation of oaks are under polygenic control and widespread in clusters across the genome.
Keywords: QTL; leaf morphology; repeatability; genetic map; Q. robur
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Yazdani, R., Scotti, I., Jansson, G., Plomion, C., & Mathur, G. (2003). Inheritance and diversity of simple sequence repeat (SSR) microsatellite markers in various families of Picea abies. Hereditas, 138(3), 219–227.
Abstract: A large number of sequence-specific SSRs were screened by using electrophoresis on metaphore agarose gels with the bands visualized by ethidium bromide staining. Many SSRs appeared as codominant and many as dominant markers, with presence or absence of bands. A simple Mendelian inheritance pattern for most codominant and dominant SSR loci was found. For many codominant SSR markers, null alleles were detected. The proportion of dominant microsatellites detected in this study (close to 50 %) was much higher than that commonly reported in many other studies. A high proportion of dominant markers together with a high frequency of codominant markers with null alleles may represent two important limitations for the use of microsatellites in different studies. On the other hand, many polymorphic codominant SSR microsatellite markers were found to be highly repeatable, and can be used for population studies, seed certification, quality control of controlled crosses, paternity analysis, pollen contamination, and mapping of QTL in related families. In this paper, we report on the inheritance pattern and diversity of codominant and dominant SSR microsatellites in seven families of Picea abies sharing a common mother.
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Marcon, E., & Puech, F. (2003). Evaluating the geographic concentration of industries using distance-based methods. J. Econ. Geogr., 3(4), 409–428.
Abstract: We propose new methods for evaluating the spatial distribution of firms. To assess whether firms are concentrated or dispersed, economists have traditionally used indices that analyse the heterogeneity of a spatial structure at a single geographic level. We introduce distance-based methods, Besag's L function (derived from Ripley's K function) and Diggle and Chetwynd's D function to describe simultaneously spatial distribution at different geographical scales. Our empirical applications consider the distribution of French manufacturing firms in the Paris area and in France generally. For some geographic levels, results show significant concentration or dispersion of firms according to their sector of activity.
Keywords: agglomeration; clustering; geographic concentration; location of firms
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Clair, B., Arinero, R., Leveque, G., Ramonda, M., & Thibaut, B. (2003). Imaging the mechanical properties of wood cell wall layers by atomic force modulation microscopy. IAWA J., 24(3), 223–230.
Abstract: Atomic Force Microscopy in force modulation mode was used to study the elastic properties of the different fibre wall layers of the tension wood of holm oak and normal wood of boco. The method is based on the measurement of the resonance frequency of the microscope lever in contact with the sample. This frequency is related to the reduced Young modulus E* = E/(1-nu(2)) of the material, supposed to be isotropic. 'Elastic' images of the cell are obtained simultaneously with the topographic images, which allows the observation of the mechanical properties of the cells at a nanometric scale. Layers G, S-1, S-2 and ML can clearly be distinguished. By comparison with known materials an estimation of the absolute modulus is given in the range 5-20 GPa, but should be considered with caution, because the inherent anisotropy of the materials has not been taken into account.
Keywords: wood; cell wall; mechanical properties; elastic modulus; tension wood
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Melieres, M. A., Pourchet, M., Charles-Dominique, P., & Gaucher, P. (2003). Mercury in canopy leaves of French Guiana in remote areas. Sci. Total Environ., 311(1-3), 261–267.
Abstract: A study of total Hg concentration in the foliage of the canopy was carried out in two remote areas in French Guiana. The sampled canopy is representative of the French Guiana canopy. The concentration in the foliage, 64+/-14 ng g(-1) (dry wt.), is used to estimate the annual input of total Hg to the soil through the litterfall, found to be 45+/-10 mug m(-2) y(-1). As translocation is negligible, mercury in the canopy originates mainly from atmospheric uptake by the leaves and this litterfall deposit represents a direct atmospheric input from the background atmospheric load into the soil. (C) 2003 Elsevier Science B.V. All rights reserved.
Keywords: mercury; canopy; rainforest; Hg atmosphere soil transfer
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Lobova, T. A., Mori, S. A., Blanchard, F., Peckham, H., & Charles-Dominique, P. (2003). Cecropia as a food resource for bats in French Guiana and the significance of fruit structure in seed dispersal and longevity. Am. J. Bot., 90(3), 388–403.
Abstract: Cecropia (Cecropiaceae) is a Neotropical genus of pioneer plants. A review of bat/plant dispersal interactions revealed that 15 species of Cecropia are consumed by 32 species of bats. In French Guiana, bats were captured in primary and secondary forests, yielding 936 fecal samples with diaspores, among which 162 contained fruits of C. obtusa, C. palmata, and C. sciadophylla. A comparative morphological and anatomical study of fruits and seeds taken directly from herbarium specimens, bat feces, and an experimental soil seed bank was made. Contrary to previous reports, the dispersal unit of Cecropia is the fruit not the seed. Bats consume the infructescence, digest pulp derived from the enlarged, fleshy perianth, and defecate the fruits. The mucilaginous pericarp of Cecropia is described. The external mucilage production of Cecropia may facilitate endozoochory. The exocarp and part of the mesocarp may be lost after passage through the digestive tract of bats, but fruits buried for a year in the soil seed bank remain structurally unchanged. Fruit characters were found to be useful for identifying species of bat-dispersed Cecropia. Bat dispersal is not necessary for seed germination but it increases seed survival and subsequent germination. Fruit structure plays a significant role in seed longevity.
Keywords: bat dispersal; Cecropia; French Guiana; fruit anatomy; fruit morphology; mucilage; Neotropical bats; soil seed bank
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