32 research outputs found

    Deciphering the impact of uncertainty on the accuracy of large wildfire spread simulations

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    Predicting wildfire spread is a challenging task fraught with uncertainties. ‘Perfect’ predictions are unfeasible since uncertainties will always be present. Improving fire spread predictions is important to reduce its negative environmental impacts. Here, we propose to understand, characterize, and quantify the impact of uncertainty in the accuracy of fire spread predictions for very large wildfires. We frame this work from the perspective of the major problems commonly faced by fire model users, namely the necessity of accounting for uncertainty in input data to produce reliable and useful fire spread predictions. Uncertainty in input variables was propagated throughout the modeling framework and its impact was evaluated by estimating the spatial discrepancy between simulated and satellite-observed fire progression data, for eight very large wildfires in Portugal. Results showed that uncertainties in wind speed and direction, fuel model assignment and typology, location and timing of ignitions, had a major impact on prediction accuracy.We argue that uncertainties in these variables should be integrated in future fire spread simulation approaches, and provide the necessary data for any firemodel user to do soinfo:eu-repo/semantics/publishedVersio

    Records of Mantodea (Insecta) collected with light trap at 45 meters height over an Amazon forest canopy, at ZF-2 nucleus, Manaus, Brazil

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    Insect collections were carried out monthly from January to December of 2004, during three nights of lunar transition third quarter moon/new moon from 18 p.m. to 6 a.m. They were collected over a vertical white sheet illuminated by a 250 watts mixed light and a 20 watts black light (BL) and black light bulb (BLB) lamps. The light trap was mounted at 45 meters height in a metallic tower of 50 meters height, in a "platô de terra firme", in the Cueiras River basin, in Manaus, Amazonas, Brazil. It was collected 23 species of Mantodea: Chaeteessidae (1 species); Mantoididae (2); Mantidae (15); Thespidae (2) and Acanthopidae (3). Six new species were registered and they will be described opportunely in the following genera: Cardioptera Burmeister, 1838; Phyllovates Kirby, 1904; Pseudovates Saussure, 1869; Stagmomantis Saussure, 1869; Stagmatoptera Burmeister, 1838 and Metilia Stal, 1877. Three species previously recorded to an indetermined Brazilian region are being recorded to Brazilian Amazon: Heterovates pardalina Saussure, 1872; Macromantis ovalifolia (Stoll, 1813) and Photina reticulata (Burmeister, 1838). Four records are new for the Amazonas state: Angela guianensis Rehn, 1906; Photina gracillis Giglio-Tos, 1915; Raptrix perspicua (Fabricius, 1787) and Vates festae Gigio-Tos, 1914. The specimens number collected monthly are presented for each species.Foram realizadas coletas mensais de insetos de janeiro a dezembro de 2004, durante três noites de transição lunar minguante/nova, das 18:00 às 06:00 horas. Os espécimes foram capturados em um lençol iluminado com lâmpada de 250 watts, luz mista de vapor de mercúrio e lâmpada de 20 watts black light (BL) e black light bulb (BLB). A armadilha foi montada a 45 metros de altura numa torre metálica de 50 metros, que ultrapassa a maioria das copas das árvores, num platô de terra firme, na bacia do rio Cuieiras, Manaus, Amazonas, Brasil. Foram coletados 23 espécies de Mantodea, sendo Chaeteessidae (1 espécie); Mantoididae (2); Mantidae (15); Thespidae (2) e Acanthopidae (3). Seis espécies são novas e serão descritas oportunamente nos seguintes gênerosCardioptera Burmeister, 1838, Phyllovates Kirby, 1904, Pseudovates Saussure, 1869, Stagmomantis Saussure, 1869, Stagmatoptera Burmeister, 1838 e Metilia Stal, 1877. Três espécies registradas para o Brasil sem uma região determinada estão sendo registradas para a Amazônia brasileiraHeterovates pardalina Saussure, 1872, Macromantis ovalifolia (Stoll, 1813) e Photina reticulata (Burmeister, 1838). Quatro registros são novos para o estado do AmazonasAngela guianensis Rehn, 1906, Photina gracillis Giglio-Tos, 1915, Raptrix perspicua (Fabricius, 1787) e Vates festae Gigio-Tos, 1914. Os números de indivíduos, em cada coleta mensal, são apresentados para cada espécie

    Assignment of the bisulfide bridges in bothropstoxin-I, a Myonecrotic Lys49 PLA2 homolog from bothrops jararacussu snake venom

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    Bothropstoxin-I (BthTX-I), a Lys49 phospholipase A2 homolog with no apparent catalytic activity, was first isolated from Bothrops jararacussu snake venom and completely sequenced in this laboratory. It is a 121-amino-acid single polypeptide chain, highly myonecrotic, despite its inability to catalyze hydrolysis of egg yolk phospholipids, and has 14 half-cystine residues identified at positions 27, 29, 44, 45, 50, 51, 61, 84, 91, 96, 98, 105, 123, and 131 (numbering according to the conventional alignment including gaps, so that the last residue is Cys 131). In order to access its seven disulfide bridges, two strategies were followed: (1) Sequencing of isolated peptides from (tryptic + SV8) and chymotryptic digests by Edman-dansyl degradation; (2) crystallization of the protein and determination of the crystal structure so that at least two additional disulfide bridges could be identified in the final electron density map. Identification of the disulfide-containing peptides from the enzymatic digests was achieved following the disappearance of the original peptides from the HPLC profile after reduction and carboxymethylation of the digest. Following this procedure, four bridges were initially identified from the tryptic and SV8 digests: Cys50-Cysl31, Cys51-Cys98, Cys61-Cys91, and Cys84-Cys96. From the chymotryptic digest other peptides were isolated either containing some of the above bridges, therefore confirming the results from the tryptic digest, or presenting a new bond between Cys27 and Cys 123. The two remaining bridges were identified as Cys29-Cys45 and Cys44-Cysl05 by determination of the crystal structure, showing that BthTX-I disulfide bonds follow the normal pattern of group II PLA2s. © 2001 Plenum Publishing Corporation

    Expression of ion channels during differentiation of a human skeletal muscle cell line

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    An immortal, cloned cell Line (RCMH), obtained from human skeletal muscle was established in our laboratory and shown to express muscle specific proteins. We measured ligand binding to ion channels, ion currents using whole cell patch clamp and intracellular calcium both in cells grown in complete media and in cells grown for 4-40 days in media supplemented with hormones and nutrients (differentiating media). Markers for differentiated muscle, such as the muscle isoform of creatine kinase and the cytoskeletal proteins alpha-actinin, alpha-sarcomeric actin, myosin and titin were present in early stages. Receptors for gamma toxin from Tityus serrulatus scorpion venom, a specific modulator for voltage dependent sodium channels, were present (0.9-1.0 pmol mg(-1) protein) during stage 1 (0-6 days in culture with differentiating media) and increased by 50% in stage 3 (more than 13 days in differentiating media). High and low affinity dihydropyridine receptors present in stage 1 convert into a single type of high affinity receptors in stage 3. Both intracellular calcium release and InsP(3) receptors were evident in stage 1 but ryanodine receptors were expressed only in stage 3. RCMH cells showed no voltage sensitive currents in stage 1. Between 7 and 10 days in differentiating media (stage 2), an outward potassium current was observed. Small inward currents appeared only in stage 3; we identified both tetrodotoxin sensitive and tetrodotoxin resistant sodium currents as well as calcium currents. This pattern is consistent with the expression of voltage dependent calcium release before appearance of both the action potential and ryanodine receptors
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