830 resultados para Southwestern Montana
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More than 30 epiphytic lichens, collected in Agadir (Morroco) and along a 150-km transect from the Atlantic Ocean eastward, were analyzed for their metal content and lead isotopic composition. This dataset was used to evaluate atmospheric metal contamination and the impact of the city on the surrounding area. The concentrations of Cu, Pb, and Zn (average ± 1 SD) were 20.9 ± 15.2 μg g−1, 13.8 ± 9.0 μg g−1, and 56.6 ± 26.6 μg g−1, respectively, with the highest values observed in lichens collected within the urban area. The 206Pb/207Pb and 208Pb/207Pb ratios in the lichens varied from 1.146 to 1.186 and from 2.423 to 2.460, respectively. Alkyllead-gasoline sold in Morocco by the major petrol companies gave isotopic ratios of 206Pb/207Pb = 1.076–1.081 and 208Pb/207Pb = 2.348–2.360. These new, homogeneous values for gasoline-derived lead improve and update the scarce isotopic database of potential lead sources in Morocco, and may be of great value to future environmental surveys on the presence of lead in natural reservoirs, where it persists over time (e.g., soils and sediments). The interest of normalizing metal concentrations in lichens to concentrations of a lithogenic element is demonstrated by the consistency of the results thus obtained with lead isotopic ratios. Leaded gasoline contributed less than 50% of the total amount of lead accumulated in lichens, even in areas subject to high vehicular traffic. This strongly suggests that the recent banishment of leaded gasoline in Morocco will not trigger a drastic improvement in air quality, at least in Agadir.
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The names Opuntia bulbispina, O. clavata, O. emoryi and O. grahamii, originally proposed by George Engelmann between 1848 and 1856, are reviewed and typified after new findings of previously unknown voucher specimens. Original materials collected by some of the collaborators employed by Engelmann during the Mexican Boundary Survey were discovered in a loan from the Torrey Herbarium at the New York Botanical Garden (NY). Many of the materials include fragments of stems and fruits, and others include only sectioned flowers and some seeds. Particularly good descriptions of the species here concerned were published in Engelmann’s “Synopsis of the Cactaceae” in 1857, and exceptional illustrations were produced by Paulus Roetter and printed in “Cactaceae of the Boundary” in 1859. The problems surrounding some previous typifications of these names range from typification of joint lectotypes to illegitimate typifications of illustrations when original material was known to exist. The materials selected for typification were collected by the Mexican Boundary Survey and are lodged at the herbaria of the Missouri Botanical Garden (MO) and the New York Botanical Garden (NY); some are illustrations published by Engelmann.
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We evaluate the effects of spatial resolution on the ability of a regional climate model to reproduce observed extreme precipitation for a region in the Southwestern United States. A total of 73 National Climate Data Center observational sites spread throughout Arizona and New Mexico are compared with regional climate simulations at the spatial resolutions of 50 km and 10 km for a 31 year period from 1980 to 2010. We analyze mean, 3-hourly and 24-hourly extreme precipitation events using WRF regional model simulations driven by NCEP-2 reanalysis. The mean climatological spatial structure of precipitation in the Southwest is well represented by the 10 km resolution but missing in the coarse (50 km resolution) simulation. However, the fine grid has a larger positive bias in mean summer precipitation than the coarse-resolution grid. The large overestimation in the simulation is in part due to scale-dependent deficiencies in the Kain-Fritsch convective parameterization scheme that generate excessive precipitation and induce a slow eastward propagation of the moist convective summer systems in the high-resolution simulation. Despite this overestimation in the mean, the 10 km simulation captures individual extreme summer precipitation events better than the 50 km simulation. In winter, however, the two simulations appear to perform equally in simulating extremes.
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A recent field campaign in southwest England used numerical modeling integrated with aircraft and radar observations to investigate the dynamic and microphysical interactions that can result in heavy convective precipitation. The COnvective Precipitation Experiment (COPE) was a joint UK-US field campaign held during the summer of 2013 in the southwest peninsula of England, designed to study convective clouds that produce heavy rain leading to flash floods. The clouds form along convergence lines that develop regularly due to the topography. Major flash floods have occurred in the past, most famously at Boscastle in 2004. It has been suggested that much of the rain was produced by warm rain processes, similar to some flash floods that have occurred in the US. The overarching goal of COPE is to improve quantitative convective precipitation forecasting by understanding the interactions of the cloud microphysics and dynamics and thereby to improve NWP model skill for forecasts of flash floods. Two research aircraft, the University of Wyoming King Air and the UK BAe 146, obtained detailed in situ and remote sensing measurements in, around, and below storms on several days. A new fast-scanning X-band dual-polarization Doppler radar made 360-deg volume scans over 10 elevation angles approximately every 5 minutes, and was augmented by two UK Met Office C-band radars and the Chilbolton S-band radar. Detailed aerosol measurements were made on the aircraft and on the ground. This paper: (i) provides an overview of the COPE field campaign and the resulting dataset; (ii) presents examples of heavy convective rainfall in clouds containing ice and also in relatively shallow clouds through the warm rain process alone; and (iii) explains how COPE data will be used to improve high-resolution NWP models for operational use.
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Accurate archaeological and palaeoenvironmental reconstructions using phytoliths relies on the study of modern reference material. In eastern Acre, Brazil, we examined whether the five most common forest types present today were able to be differentiated by their soil phytolith assemblages, and thus provide analogues with which to compare palaeoecological assemblages from pre-Columbian earthwork sites in the region. Surface soils and vegetation from dense humid evergreen forest, dense humid evergreen forest with high palm abundance, palm forest, bamboo forest and fluvial forest were sampled and their phytoliths analysed. Relative phytolith frequencies were statistically compared using Principal Components Analyses (PCAs). We found the major differences in species composition to be well-represented by the phytolith assemblages as all forest types, apart from the two sub-types of dense humid evergreen forest, could be differentiated. Larger phytoliths from the sand fraction were found to be more ecologically diagnostic than those from the silt fraction. The surface soil phytolith assemblages we analysed can therefore be used as analogues to improve the accuracy of archaeological and palaeoecological reconstructions in the region.
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A Regional Climate Model (RegCM3) 10-year (1990-1999) simulation over southwestern South Atlantic Ocean (SAO) is evaluated to assess the mean climatology and the simulation errors of turbulent fluxes over the sea. Moreover, the relationship between these fluxes and the rainfall over some cyclogenetic areas is also analyzed. The RegCM3 results are validated using some reanalyses datasets (ERA40, R2, GPCP and WHOI). The summer and winter spatial patterns of latent and sensible heat fluxes simulated by the RegCM3 are in agreement with the reanalyses (WHOI, R2 and ERA40). They show large latent heat fluxes exchange in the subtropical SAO and at higher latitudes in the warm waters of Brazil Current. In particular, the magnitude of RegCM3 latent heat fluxes is similar to the WHOI, which is probably related to two factors: (a) small specific humidity bias, and (b) the RegCM3 flux algorithm. In contrast, the RegCM3 presents large overestimation of sensible heat flux, though it simulates well their spatial pattern. This simulation error is associated with the RegCM3 underestimation of the 2-m air temperature. In southwestern SAO, in three known cyclogenetic areas, the reanalyses and the RegCM3 show the existence of different physical mechanisms that control the annual cycles of latent/sensible heating and rainfall. It is shown that over the eastern coast of Uruguay (35A degrees-43A degrees S) and the southeastern coast of Argentina (44A degrees-52A degrees S) the sea-air moisture and heat exchange play an important role to control the annual cycle of precipitation. This does not happen on the south/southeastern coast of Brazil.
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The Guarguaraz Complex, in western Argentina, comprises a metasedimentary assemblage, associated with mafic sills and ultramafic bodies intruded by basaltic dikes, which are interpreted as Ordovician dismembered ophiolites. Two kinds of dikes are recognized, a group associated with the metasediments and the other ophiolite-related. Both have N-MORB signatures, with epsilon(Nd) between +3.5 and +8.2, indicating a depleted source, and Grenville model ages between 0.99 and 1.62 Ga. A whole-rock Sm-Nd isochron yielded an age of 655 +/- 76 Ma for these mafic rocks, which is compatible with cianobacteria and acritarchae recognized in the clastic metasedimentary platform sequences, that indicate a Neoproterozoic (Vendian)-Cambrian age of deposition. The Guarguaraz metasedimentary-ophiolitic complex represents, therefore, a remnant of an oceanic basin developed to the west of the Grenville-aged Cuyania terrane during the Neoproterozoic. The southernmost extension of these metasedimentary sequences in Cordon del Portillo might represent part of this platform and not fragments of the Chilenia terrane. An extensional event related to the fragmentation of Rodinia is represented by the mafic and ultramafic rocks. The Devonian docking of Chilenia emplaced remnants of ocean floor and slices of the Cuyania terrane (Las Yaretas Gneisses) in tectonic contact with the Neoproterozoic metasediments, marking the Devonian western border of Gondwana. (C) 2009 Elsevier Ltd. All rights reserved.
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The southwestern margin of the Eastern Ghats Belt characteristically exposes mafic dykes intruding massif-type charnockites. Dykes of olivine basalt of alkaline composition have characteristic trace element signatures comparable with Ocean Island Basalt (OIB). Most importantly strong positive Nb anomaly and low values of Zr/Nb ratio are consistent with OIB source of the mafic dykes. K-Ar isotopic data indicate two cooling ages at 740 and 530 Ma. The Pan-African thermal event could be related to reactivation of major shear zones and represented by leuco-granite vein along minor shear bands. And 740 Ma cooling age may indicate the low grade metamorphic imprints, noted in some of the dykes. Although no intrusion age could be determined from the present dataset, it could be constrained by some age data of the host charnockite gneiss and Alkaline rocks of the adjacent Prakasam Province. Assuming an intrusion age of similar to 1.3 Ga, Sr-Nd isotopic composition of the dykes indicate that they preserved time-integrated LREE enrichment. In view of the chemical signatures of OIB source, the mafic dykes could as well be related to continental rifting, around 1.3 Ga, which may have been initiated by intra-plate volcanism.
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O primeiro registro para o Atlântico Sul ocidental de uma espécie do gênero Malacoraja Stehmann, 1970 é feita com base na descrição de Malacoraja obscura, espécie nova, proveniente do talude continental do Sudeste brasileiro dos estados do Espírito Santo e Rio de Janeiro em profundidades de 808-1105 m. A espécie nova é conhecida através de cinco exemplares e é distinta de seus congêneres pela sua coloração dorsal composta por numerosas manchas esbranquiçadas e pequenas na região do disco e nadadeiras pélvicas, por apresentar uma fileira irregular de espinhos ao longo da superfície dorsal mediana da cauda a qual persiste em espécimes maiores (desde a base da cauda até dois-terços do seu comprimento numa fêmea de 680 mm de comprimento total, CT) e uma região pequena desprovida de dentículos na base ventral da cauda (estendendo somente até a margem distal da nadadeira pélvica). Outros caracteres diagnósticos em combinação incluem a ausência de espinhos escapulares em indivíduos maiores, número elevado de fileiras dentárias (64/62 fileiras num macho subadulto de 505 mm de CT e 76/74 numa fêmea de 680 mm de CT) e de vértebras (27-28 Vtr, 68-75 Vprd), coloração ventral do disco uniformemente castanha escura, duas fenestras pós-ventrais na cintura escapular, fenestra pós-ventral posterior grande, forame magno circular e dois forames para a carótida interna na placa basal ventral do neurocrânio. Machos adultos não são conhecidos, porém uma descrição anatômica de M. obscura, sp. nov., é fornecida. Comparações são realizadas com todo o material conhecido de M. kreffti, com a literatura sobre M. senta e com material abundante de M. spinacidermis da África do Sul; M. obscura, sp. nov., assemelha-se mais a M. spinacidermis do Atlântico Sul oriental em esqueleto dérmico, coloração e tamanho. Malacoraja é monofilético devido à sua espinulação e apêndices rostrais conspícuos e é aparentemente composta por dois grupos de espécies, um para M. obscura e M. spinacidermis e outro para M. kreffti e M. senta, porém a elucidação das relações filogenéticas entre as espécies necessita de mais informações anatômicas, principalmente das duas últimas espécies.
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Diet composition of the blue marlin, Makaira nigricans, from the southwestern equatorial Atlantic Ocean was analyzed between October 2004 and November 2005. In the 226 stomachs of fish ranging between 100 and 311 cm lower jaw -fork length (LJFL), 44 items were identified, including 31 fishes and 13 cephalopods. Seventy stomachs were empty (23.6 %). M. nigricans fed preferentially on heavy and muscular scombrid fishes especially upon the skipjack tuna, Katsuwonus pelamis (Linnaeus, 1758), probably to sustain their high metabolism, and on a variety of other items composed mainly by epipelagic species of fish and cephalopods.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Com o objetivo de avaliar a influência da temperatura sobre a porcentagem de germinação e o índice de velocidade de germinação (IVG) de sementes de Annona montana, conhecida como falsa graviola, espécie com potencial para porta-enxerto das variedades comerciais, testaram-se quatro temperaturas (20; 25; 30 e 35ºC). O trabalho foi desenvolvido em laboratório em câmaras de germinação tipo BOD, utilizando-se de sementes de três plantas provenientes do Banco de Germoplasma do Departamento de Produção Vegetal da Faculdade de Ciências Agrárias e Veterinárias - UNESP, Câmpus de Jaboticabal-SP. O delineamento experimental foi o inteiramente casualizado, com quatro repetições, com dez sementes cada. Pelos resultados obtidos, tem-se que tanto para o parâmetro porcentagem de germinação como para o IVG, os maiores valores observados foram para as sementes na temperatura de 30ºC (55% de germinação e IVG = 0,153), seguido da temperatura de 25ºC (25% de germinação e IVG = 0,088). Para as temperaturas de 20ºC e 35ºC, não foi observada ocorrência de germinação. A análise estatística dos dados de porcentagem de germinação foi transformada em arc-sen square root (x/100) e as médias foram comparadas pelo teste de Tukey, a 5% de probabilidade.
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The taxonomic identity of specimens of the genus Hippolyte Leach, 1814 of Laguna de Términos was considered including the colour and the presence-absence of tufts of plumose setae on the dorsal surface of the carapace and abdomen as secondary characteristics to morphological features of taxonomic value. Two groups were formed based on appearance: one transparent with setae and another green without setae. The analysis of five morphological characteristics in adult females of the two groups made it possible to identify only H. zostericola (Smith, 1873). Fecundity and fertility were similar (0.5>p>0.2) in both groups. The first zoea of both groups were also morphologically similar. Considering these results, it is concluded that the only species collected was H. zoslericola and that it has two phenotypical types. It is recomended that the morphological analysis of all larval stages be carried out.