590 research outputs found

    Journal of a missionary tour to the Labaya Country (Guinea/Conakry) in 1850

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    The paper is an edited transcription of the journal of a missionary based in Freetown (Sierra Leone), who in 1850 visited part of what is today Guinea-Conakry, inhabited by Susu people. It is particularly informative about the protocols established in this region for commerce. The original text is supplemented by an introduction, a map, annotation and a detailed index

    Radiative heating in contrail cirrus

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    We developed an effective model (within our contrail cirrus prediction model, CoCiP) which computes the radiative heating rate in both the longwave and shortwave spectral ranges. The model parameterizes the impact of radiative heating on turbulent mixing and sublimation of ice particles in a thin cirrus layer

    Genotoxicity testing of antiparasitic nitrofurans in the Drosophila wing somatic mutation and recombination test

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    Nifurtimox and eight structurally related 5-nitrofuran compounds active against Trypanosoma cruzi were tested for genotoxicity in the wing somatic mutation and recombination test in Drosophila melanogaster. Nifurtimox, compound ada and compound 1B were clearly mutagenic and recombinogenic whereas the remaining six compounds were negative. In contrast to the situation in bacterial mutagenicity tests, nitroreductase activity is probably not decisive for the genotoxicity of these compounds in Drosophila. The three non-genotoxic nitrofurans with high antiparasitic activity are promising candidates for the replacement of nifurtimox. However, these compounds require further genotoxicity testing in eukaryotic assay systems for a final evaluatio

    Genotoxicity of 2-amino-3-methylimidazo(4, 5-f)quinoline (IQ) and related compounds in Drosophila

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    The potent food mutagen and carcinogen 2-amino-3-methyl-imidazo[4, 5-f]quinoline (IQ) and the structurally related heterocyclic aromatic amines 2-aminoimidazo[4, 5-f]quinoline (demethyl-IQ) and 2-amino-l-methylinudazo(4, 5-f)quinoline (iso-IQ) were assayed for genotoxicity in the wing somatic mutation and recombination test (SMART) as well as in the sex-linked recessive lethal (SLRL) test in Drosophila melanogaster. In addition, 3-methyl-2-nitroimidazo[4, 5-f]-quinoline (nitro-IQ), 2-nitrofluorene and 1, 8-dinitropyrene were also assayed in the wing spot test. IQ was clearly muta-genic in the SLRL test with highest activity in spermatids. Iso-IQ was more active than IQ whereas demethyl-IQ was inactive in this test. The same pattern of results was obtained in the wing SMART: iso-IQ produced >2-fold higher frequencies of spots than IQ and demethyl-IQ was clearly negative. In addition, nitro-IQ exhibited an approximately equal genotoxic activity as IQ. 2-Nitrofluorene and 1, 8-di-nitropyrene were both inactive in the wing spot test. These data provide good evidence for a correlation of genotoxic effects in germinal and somatic cells, and for the practical advantage of the wing spot test in Drosophila. Moreover, the results show structure-activity relationships among the heterocyclic aromatic amines and nitro compounds similar to those found in Salmonell

    Secondary succession in a Swiss mire after a bog burst

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    Severe natural disturbances can lead to the recovery of the original vegetation or the shift to new vegetation types. While post-disturbance succession is well documented for regularly disturbed ecosystems, little is known about the pathways and rapidity of vegetation dynamics after rare events such as peat mass movements in bogs. We monitored the floristic changes in a mire subject to a bog burst in 1987 for two decades through the repeated sampling of permanent plots. The mean species number per plot increased continuously, while the evenness increased only in the first decade and then slightly decreased. Declining species were mostly mire species, while colonist species were mostly wet meadow species. Species turnover was higher in the first decade after the disturbance, and was also higher in the area of peat erosion than in the area of peat accumulation. Changes in plant species composition indicate a succession towards tall-forb vegetation (Filipendulion), acidic fen vegetation (Caricion fuscae) and swamp willow forest (Salicion). We conclude that the effects of the disturbance are still ongoing, and that the mire's potential for recovery is therefore difficult to predic

    Facial expressions and personality: A kinematical investigation during an emotion induction experiment

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    Background/Aims: In order to elucidate the relationship between personality traits and expression of positive emotions in healthy volunteers, standardized personality inventories and kinematical analysis of facial expressions can be helpful and were applied in the present study. Methods: Markers fixed at distinct points of the face emitting ultrasonic signals at high frequency gave a direct measure of facial movements with high spatial-temporal resolution. Forty-six healthy participants (mean age: 40.7 years; 20 males, 26 females) watching a witty movie ('Mr. Bean') were investigated. Results: Speed of `laughing' was associated with higher scores on Zuckerman's Sensation Seeking Scale and NEO-FFI (Openness to Experience). Conclusion: Kinematical analysis of facial expressions seems to reflect sensation seeking and related personality styles. Higher speed of facial movements in sensation seekers suggests lowered serotonergic function. Copyright (c) 2006 S. Karger AG, Basel

    Five-year changes in Swiss mire vegetation

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    To assess whether short-term changes in mire vegetation can be detected using the phytosociological approach, paired vegetation relevés from two surveys of 112 mire sites of Switzerland were assigned to phytosociological alliances through a numerical approach. About 30% of the plots were assigned to different alliances in the two surveys. These transitions were analysed based on species frequencies and interpreted ecologically using Landolt's indicator values. Transitions between different alliances were more frequently related to the appearance of new species rather than to the disappearance of species. Transitions from and to peat bog communities were frequent. Many plots with fen vegetation were transformed into other wetland types. Fen-grassland increased in abundance, mainly at the cost of small-sedge fens. To re-establish the function of the Swiss mires as peat producers, we recommend to raise the mean summer water table to a maximum depth of 10c

    A phytosociological classification of Swiss mire vegetation

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    The mapping and monitoring of Swiss mires has so far relied on a classification system based on expert judgement, which was not supported by a quantitative vegetation analysis and which did not include all wetland vegetation types described in the country. Based on a spatially representative sample of 17,608 relevés from 112 Swiss mires, we address the following questions: (1) How abundant are wetland vegetation types (phytosociological alliances) in Swiss mires? (2) How are they distributed across the country--is there a regional pattern? (3) How clearly are they separated from each other? (4) How clear and reliable is their ecological interpretation? Using published wetland vegetation relevés and lists of diagnostic species for phytosociological units (associations and alliances) established by experts, we developed a numerical method for assigning relevés to units through the calculation of similarity indices. We applied this method to our sample of 17,608 relevés and estimated the total area covered by each vegetation type in Switzerland. We found that vegetation types not included in previous mapping were either rare in Switzerland (partly due to mire drainage) or poorly distinguished from other vegetation units. In an ordination, the Swiss mire vegetation formed a triangular gradient system with the Sphagnion medii, the Caricion davallianae and the Phragmition australis as extreme types. Phytosociological alliances were clearly separated in a subset of 2,265 relevés, which had a strong similarity to one particular association, but poorly separated across all relevés, of which many could not be unequivocally assigned to one association. However, ecological gradients were reflected equally well by the vegetation types in either case. Overall, phytosociological alliances distinguished until now proved suitable schemes to describe and interpret vegetation gradients. Nevertheless, we see the urgent need to establish a data base of Swiss wetland relevés for a more reliable definition of some vegetation unit

    Protection by Panax ginseng C.A. Meyer against the genotoxicity of doxorubicin in somatic cells of Drosophila melanogaster

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    Panax ginseng is one of the most widely prescribed herbal medicines for the treatment of cancer, diabetes, chronic inflammation, and neurodegenerative and cardiovascular diseases. Since the use of alternative medicines in combination with conventional therapy may increase the risk of unwanted interactions, we investigated the possible genotoxicity of a water-soluble form of the dry root of P. ginseng (2.5, 5.0 or 10.0 mg/mL) and its ability to protect against the genotoxicity of doxorubicin (DOX; 0.125 mg/mL) by using the Drosophila melanogaster wing somatic mutation and recombination test (SMART) with standard and high-bioactivation crosses of flies. Panax ginseng was not genotoxic at the concentrations tested, whereas DOX-induced genotoxicity in marker-heterozygous flies resulted mainly from mitotic recombination. At low concentrations, P. ginseng had antirecombinogenic activity that was independent of the concentration of extract used. Recombination events may promote cancer, but little is known about the ability of P. ginseng to inhibit such recombination or modulate DNA repair mechanisms.CNPqCoordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES)FAPEMIGUF
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