1000 resultados para Pteridium aquilinum (L .) Kuhn.


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Two new Standard pollen diagrams from the raised bog AgerÃds mosse in central Scania are presented and discussed. They have been made giving extensive consideration to the NAP and spores also. The new diagrams comprise in the main only the Post-glacial and can easily be compared with the earlier published Standard diagram from the bog (T. NILSSON 1935). The development of the Post-glacial Vegetation in the surroundings is also discussed and compared with the conditions in the southernmost part of the province (BjärsjÃholmssjÃn, T. Nilsson 1961). One of the new diagrams has been prepared in connection with the study of a core brought up by means of a special borer in order to bring about C14 datings. The core was almost Ãmlong and had a diameter of 6 cm. It was divided into pieces of 2-6 cm, which were preserved. After the preparation of the pollen diagram, suitable samples were selected for C14 dating. In all 33 samples, comprising the whole Post-glacial inclusive of the youngest part of the Late-glacial, were C14-dated. With the aid of the C14 dates the growth conditions of the bog are discussed. After very slow Sedimentation of predominantly minerogenous deposits in the last part of the Late-glacial, and still slow Sedimentation of gyttjas in the oldest part of the Post-glacial, the rate of growth (primarily of the gyttja) distinctly increased in the first part of the Late Boreal. A temporary retardation of the growth of the sphagnum peat at the end of the Sub-boreal is probably entirely local. The average rate of growth of the really highly humified parts of the old sphagnum peat amounts to 42 mm per Century, that of the slightly humified young sphagnum peat 81 mm per Century or somewhat more. Based on the C14-determinations, the pollen zone boundaries have been given the following approximate dates: boundary Late-glacial/Post-glacial (DR/PB) 8300 B.C., boundary Pre-boreal/Boreal (PB/BO) 7900 B.C., boundary Early Boreal/Late Boreal (BO 1/2) 6800 B.C., boundary Boreal/Atlantic (BO/AT) 6200 B.C., boundary Early Atlantic/Late Atlantic (AT 1/2) 4600 B.C. (?), boundary Atlantic/Sub-boreal (AT/SB) 3300 B.C., boundary Early Sub-boreal/Late Sub-boreal (SB 1/2) 1700-1800 B.C., boundary Sub-boreal/Sub-atlantic (SB/ SA) 300 B.C., boundary Early Sub-atlantic/Late Sub-atlantic (SA 1/2) 650 A.D.

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Waste biomass is generated during the conservation management of semi-natural habitats, and represents an unused resource and potential bioenergy feedstock that does not compete with food production. Thermogravimetric analysis was used to characterise a representative range of biomass generated during conservation management in Wales. Of the biomass types assessed, those dominated by rush (Juncus effuses) and bracken (Pteridium aquilinum) exhibited the highest and lowest volatile compositions respectively and were selected for bench scale conversion via fast pyrolysis. Each biomass type was ensiled and a sub-sample of silage was washed and pressed. Demineralization of conservation biomass through washing and pressing was associated with higher oil yields following fast pyrolysis. The oil yields were within the published range established for the dedicated energy crops miscanthus and willow. In order to examine the potential a multiple output energy system was developed with gross power production estimates following valorisation of the press fluid, char and oil. If used in multi fuel industrial burners the char and oil alone would displace 3.9 Ã 105 tonnes per year of No. 2 light oil using Welsh biomass from conservation management. Bioenergy and product development using these feedstocks could simultaneously support biodiversity management and displace fossil fuels, thereby reducing GHG emissions. Gross power generation predictions show good potential.

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Within a larger program research work is being done on the history of settlement and landscape of the 'Siedlungskammer' FlÃgeln and the adjacent area. The 'Siedlungskammer' consists of an isolated pleistocene sand ground (Geest-island) surroundet by bogs. Starting from the edge of the Geest, near which large-scale archaeological excavations are carried out, three raised bog profiles were taken at 300, 500 and 4000 m off the prehistoric settlement. They were investigated by means of pollen analysis, and reflect in a decreasing way the activities of man on the Geestisland. Another pollen diagram from the nearby fen peat was worked out for comparison. At the same time it helped to date back a prehistoric sand path to the Roman period. The pollen diagrams cover the vegetational history without gaps from the early Atlantic period to modern times. The vegetation was decisively determined by the poor soils of this area. T'he pollen diagrams give evidence of the activity of settlers since the Neolithic age, with some gaps in the beginning, but later continuously from the middle of the Bronze age until the early migration period. The influence of the nearby settlement, which existed from the Birth of Christ to the 4/5th century, comes out distinctly. Among the cereals which were then cultivated here, there also was rye, at least in the 4/5th century, but most probably already during the Roman period. Besides that people cultivated barley, oats, and flax. The settlement break during the so-called dark ages between the 4/5th century and the time about 800 A.D. was confirmed by pollen analysis. During this time the area was once more covered by forests. The fluctuations of man's activities during the late Middle Ages and modern times, as they are made visible by pollen analysis, correspond to historically wellknown developments.

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A pouco conhecida vegetação de muçununga ocorre em Florestas Ombrófilas Densas de Terras Baixas no norte do Espírito Santo e Sul da Bahia, em locais de solo arenoso, úmido e fofo. Este trabalho teve como objetivo realizar estudos florísticos e fitofisionômicos para uma avaliação de como interferências antrópicas influenciaram a composição e a estrutura das muçunungas de Caravelas (17º41'13''S e 39º28'24''W) e Mucuri (18º10'29''S e 39º53'25''W), no Estado da Bahia. Foram realizadas incursões na vegetação para coletas botânicas e construção do espectro biológico. Foram feitos perfis em quatro diferentes estratos, em ambas as muçunungas. Na muçununga de Caravelas foram relacionadas 67 espécies de 32 famílias e na de Mucuri, 53 espécies de 31 famílias. Na listagem florística ficou evidenciada a maior riqueza da muçununga de Caravelas. Nos perfis é possível perceber maior equabilidade na distribuição dos indivíduos entre as espécies da muçununga de Caravelas que entre as espécies de Mucuri. Os impactos originários da atividade humana favoreceram as formas de vida hemicriptofítica e as lianas na muçununga de Mucuri. As espécies Baccharis trimera, Blechnum serrulatum, Imperata brasiliensis e Pteridium aquilinum são indicadoras dos impactos de passagem de fogo e pastejo bovino. Os impactos antrópicos nas muçunungas foram os principais responsáveis pela diminuição da biodiversidade nesse tipo de vegetação.

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A importância econômica, epidemiologia e controle das intoxicações por plantas em animais domésticos no Brasil são revisadas. Com os dados dos laboratórios de diagnóstico de diferentes regiões do país, as perdas anuais por mortes de animais foram estimadas em 820.761 a 1.755.763 bovinos, 399.800 a 445.309 ovinos, 52.675 a 63.292 caprinos e 38.559 equinos. No Brasil, atualmente, o número de plantas tóxicas é de 131 espécies e 79 gêneros e aumenta permanentemente. No entanto, a maioria das perdas são causadas por poucas plantas, incluindo Palicourea marcgravii, Amorimia spp., Senecio spp., Pteridium aquilinum, Ateleia glazioviana e Cestrum laevigatum em bovinos, Brachiaria spp em bovinos e ovinos, Nierembergia veitchii, Mimosa tenuiflora e Ipomoea asarifolia em ovinos, plantas que contêm swainsonina (Ipomoea carnea, Turbina cordata e Sida carpinifolia) em caprinos e Brachiaria humidicola e Crotalaria retusa em equinos. Os principais fatores epidemiológicos relacionados às intoxicações por plantas incluem palatabilidade, fome, sede, facilitação social, desconhecimento da planta, acesso a plantas tóxicas, dose tóxica, período de ingestão, variações de toxicidade e resistência/susceptibilidade dos animais às intoxicações. Quanto aos métodos de controle e profilaxia descrevem-se os resultados obtidos no Brasil com métodos recentemente desenvolvidos, incluindo controle biológico, aversão alimentar condicionada, utilização de variedades não tóxicas de forrageiras, utilização de animais resistentes às intoxicações e técnicas de indução de resistência.

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The contribution of four types of secondary woodlands to Scottish invertebrate biodiversity was investigated for coniferous plantation forestry, riparian ash-alder woodlands, early successional deciduous woodlands and climax deciduous woodlands. Considerable variation in the type and intensity of management within these four woodland types existed. Adult Diptera from 21 families, representing diverse trophic and ecological guilds, were sampled from 31 woodlands in the Aberdeenshire region of northeast Scotland, between June and August 2001. Environmental differences between woodlands were recorded at each site using environmental parameters such as pH and organic matter content, vegetation characteristics, including percentage canopy cover and dominant field layer plant species. Multivariate ordination techniques detected significant responses in the Dipteran communities to soil type, organic matter content, soil pH, field layer plant species richness, dominant field layer plant species and percentage cover of Pteridium aquilinum. Responses in terms of Dipteran abundance, species richness, diversity and evenness were observed to soil type and dominant species of the field layer vegetation. The role of woodland type and management in diversifying Diptera communities is discussed with a view to maintain and possibly enhance Dipteran and other invertebrate communities in Scottish secondary woodlands. (C) 2002 Elsevier Science B.V. All rights reserved.

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The recent emergence of novel pathogenic human and animal coronaviruses has highlighted the need for antiviral therapies that are effective against a spectrum of these viruses. We have used several strains of murine hepatitis virus (MHV) in cell culture and in vivo in mouse models to investigate the antiviral characteristics of peptide-conjugated antisense phosphorodiamidate morpholino oligomers (P-PMOs). Ten P-PMOs directed against various target sites in the viral genome were tested in cell culture, and one of these (5TERM), which was complementary to the 5' terminus of the genomic RNA, was effective against six strains of MHV. Further studies were carried out with various arginine-rich peptides conjugated to the 5TERM PMO sequence in order to evaluate efficacy and toxicity and thereby select candidates for in vivo testing. In uninfected mice, prolonged P-PMO treatment did not result in weight loss or detectable histopathologic changes. 5TERM P-PMO treatment reduced viral titers in target organs and protected mice against virus-induced tissue damage. Prophylactic 5TERM P-PMO treatment decreased the amount of weight loss associated with infection under most experimental conditions. Treatment also prolonged survival in two lethal challenge models. In some cases of high-dose viral inoculation followed by delayed treatment, 5TERM P-PMO treatment was not protective and increased morbidity in the treated group, suggesting that P-PMO may cause toxic effects in diseased mice that were not apparent in the uninfected animals. However, the strong antiviral effect observed suggests that with further development, P-PMO may provide an effective therapeutic approach against a broad range of coronavirus infections.

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Evidence is presented of widespread changes in structure and species composition between the 1980s and 2003â2004 from surveys of 249 British broadleaved woodlands. Structural components examined include canopy cover, vertical vegetation profiles, field-layer cover and deadwood abundance. Woods were located in 13 geographical localities and the patterns of change were examined for each locality as well as across all woods. Changes were not uniform throughout the localities; overall, there were significant decreases in canopy cover and increases in sub-canopy (2â10 m) cover. Changes in 0.5â2 m vegetation cover showed strong geographic patterns, increasing in western localities, but declining or showing no change in eastern localities. There were significant increases in canopy ash Fraxinus excelsior and decreases in oak Quercus robur/petraea. Shrub layer ash and honeysuckle Lonicera periclymenum increased while birch Betula spp. hawthorn Crataegus monogyna and hazel Corylus avellana declined. Within the field layer, both bracken Pteridium aquilinum and herbs increased. Overall, deadwood generally increased. Changes were consistent with reductions in active woodland management and changes in grazing and browsing pressure. These findings have important implications for sustainable active management of British broadleaved woodlands to meet silvicultural and biodiversity objectives.

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Pós-graduação em Medicina Veterinária - FCAV

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PURPOSE: In this study we examined the arterial-adaptive dilatation and Doppler velocimetry, especially RI values, in normal fetuses with a single umbilical artery (SUA). MATERIALS AND METHODS: We studied 195 fetuses from 18 to 39 weeks of gestational age with a prenatally identified SUA retrospectively. They were enrolled in this study if the following information applied: > 18 weeks of gestational age, no structural or chromosomal abnormalities, and histopathological confirmation of SUA. Sonographic examination included evaluation of the umbilical artery resistance and the cross-sectional area of the umbilical cord, and its vessels were measured in all cases. Small for gestational age (SGA) was diagnosed when the birth weight was below the 10th percentile for gestational age. Fetuses with intrauterine growth restriction were defined as those with biometric data below the 5th percentile. RESULTS: There were 119 cases of prenatally identified SUA which met the inclusion criteria. RI values were below the 10th percentile in 33/119 (27.33) and below the 50th percentile in 73/119 (61.33). RI values below the 10th percentile were significantly more likely to be in the normal collective than in the growth restricted collective [31/87 (35.63%) vs. 2/32 (6.25%); p = 0.001]. Even more significant differences became apparent when comparing the RI values below the 50th percentile of both groups. An umbilical artery diameter over the 90th percentile was found in 49 (41.9%) of cases and was significantly more likely to be present in normal growing fetuses than in the growth restricted group. CONCLUSION: Normal fetuses with SUA are at higher risk to be born as SGA. With our study results we can confirm the hypothesis that Doppler flow measurements and arterial diameter in SUA are different from those found in normal fetal umbilical arteries. RI values over the 50th percentile or a cross-sectional area of the artery below 95th percentile after 26th week of gestation significantly increases the risk of SGA.