22 research outputs found

    Identifying geographical patterns of wildfire orientation: a watershed-based analysis

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    We searched for geographical patterns in the orientation of wildfires, using watersheds as spatial support for the analysis. An 1975–2005 annual fire atlas of mainland Portugal was used to compute the orientation of fire perimeters and watersheds, using principal component analysis. Circular statistics were employed to test for the existence of a preferred, as opposed to random, mean fire orientation in each watershed, and to search for evidence of orographic channelling of fire by comparing fire orientation and watershed orientation. We also tested for differences in fire orientation patterns under conditions of mild versus severe fire weather. Our findings show that in the 31 year period of the study, 84% of the overall area burned is accounted for by watersheds where fires display preferential orientation. Twelve of 102 watersheds display evidence of alignment between fire and watershed orientation and we found no distinction in fire orientation as response to fire weather. The spatial arrangement of watersheds where fires present similar orientation suggests wind as a major driver of the broader patterns found in this study. Results from this analysis ought to be relevant for supporting the delineation of landscape- scale fuelbreaks

    A test for directional-linear independence, with applications to wildfire orientation and size

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    Original PaperA nonparametric test for assessing the independence between a directional random variable (circular or spherical, as particular cases) and a linear one is proposed in this paper. The statistic is based on the squared distance between nonparametric kernel density estimates and its calibration is done by a permutation approach. The size and power characteristics of various variants of the test are investigated and compared with those for classical correlation-based tests of independence in an extensive simulation study. Finally, the best-performing variant of the new test is applied in the analysis of the relation between the orientation and size of Portuguese wildfire

    Electron-beam irradiation preserves nutritional profile of Agaricus bisporus Portobello

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    All over the world, mushrooms are highly consumed due to their high contents of digestible proteins, carbohydrates, vitamins and fibers. Mushrooms contain about 90% of water, which leads to a faster deterioration due to senescence, browning, water loss and microbial attack. Despite of the immense popularity of this food worldwide, data regarding alternative technologies to increase mushrooms shelf-life are scarce. Ionizing radiation processing is recognized as a safe and effective method for conservation, being widely used to extend the shelf-life of raw foods. The present work reports the effects of storage time (0, 4 and 8 days) and electron-beam irradiation on the nutritional composition (moisture, fat, proteins, ash, carbohydrates and energy) of Agaricus bisporus Portobello samples. The irradiation was performed with a 10 MeV energy irradiator at the doses of 1, 2 and 5 kGy. The proximate composition was evaluated by AOAC official procedures. Storage time (ST) and electron-beam (EB) irradiation showed a significant interaction in all cases (p-value > 0.05), indicating that the effects potentially exerted by ST depended on EB dose and vice-versa. Considering the individual effect of each factor, EB induced more changes than ST, which in fact had a significant effect only for protein and carbohydrates. Among different EB doses, despite the significant differences, it is evident that the nutritional profiles were not greatly changed with any applied dose. Therefore, up to 5 kGy, EB seems to be a suitable conservation treatment for A. bisporus Portobello.Foundation for Science and Technology (FCT, Portugal) and FEDER under Programme PT2020 for financial support to CIMO (UID/AGR/00690/2013), C2TN (UID/Multi/04349/2013), grant to A. Fernandes (SFRH/BPD/114753/2016) and L. Barros contract; European Structural and Investment Funds (ESIF) (Regional Operational Program Norte 2020, Project ValorNatural®); Rural Development Program (Project MicoCoating, PDR2020-101-031472); International Atomic Energy Agency (IAEA) Coordinated Research Project D61024 DEXAFI.info:eu-repo/semantics/publishedVersio

    Intoxicação por Senecio spp. em bovinos no Rio Grande do Sul: condições ambientais favoráveis e medidas de controle

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    Este trabalho teve por objetivo revisar os principais aspectos da intoxicação por Senecio spp. no Rio Grande do Sul no que se refere à patologia, patogenia e epidemiologia dessa importante causa de morte em bovinos nesse Estado. Foram abordados, também, os principais fatores climáticos e ambientais que aparentemente favorecem a emergência e o estabelecimento da planta e a ocorrência da intoxicação, que tem aumentado a sua frequência nos últimos anos no Estado, e as possíveis formas de controle da planta incluindo o manejo correto do solo e a utilização de espécies domésticas menos susceptíveis nas áreas invadidas

    Répteis em fragmentos de Cerrado e Mata Atlântica no Campo das Vertentes, Estado de Minas Gerais, Sudeste do Brasil

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    Os dados sobre a fauna reptiliana em Minas Gerais são pontuais e revelam carência de informações sobre esse grupo, principalmente em regiões de transição entre a Mata Atlântica e o Cerrado. A área do estudo está situada no município de Ritápolis (21° 01' 37.07" S e 44° 19' 11.84" O), microrregião Campo das Vertentes, Estado de Minas Gerais, Sudeste do Brasil. Pretendeu-se com a presente pesquisa conhecer a composição da fauna de répteis local. As observações, capturas e coletas foram realizadas quinzenalmente, durante dois dias consecutivos, de agosto de 2005 a julho de 2006. As capturas foram realizadas por meio de armadilhas de interceptação e queda, distribuídas em oito sítios, sendo quatro em área de mata de galeria e quatro em área aberta, perfazendo um esforço amostral de 6.912 horas-balde. Foi também realizada procura ativa e encontros ocasionais com registros fotográficos dos espécimes, e, no caso de serpentes, alguns exemplares foram entregues por terceiros quando encontradas mortos. Registrou-se a presença de 31 espécies de répteis, sendo duas espécies de cágados, nove de lagartos, duas de anfisbenas e 18 de serpentes. Apenas os lagartos Cercosaura ocellata, Enyalius bilineatus e Tupinambis merianae e as serpentes Leptodeira annulata e Apostolepis assimilis foram capturados nas armadilhas de queda. Os lagartos mais comuns foram Ameiva ameiva e Mabuya frenata, e as serpentes mais abundantes foram Oxyrhophus guibei e Sibynomorphus mikanii. Os lagartos estão bem representados na área, com espécies típicas de mata, como Enyalius bilineatus, e de áreas aberta de cerrado, como Ameiva ameiva e Mabuya frenata. A fauna de serpentes possui representantes típicos de áreas abertas do Cerrado, como O. guibei e Micrurus frontalis, e de regiões florestadas, como Liophis poecilogyrus e Philodryas olfersii. A diversidade de espécies de répteis e o registro prévio de Amphisbaena dubia e Hydromedusa tectifera para o Estado de Minas Gerais indicam a grande potencialidade do Campo das Vertentes em revelar a ocorrência de espécies novas ou a ampliação na distribuição de outras

    Effects of electron-beam irradiation on fatty acids profile of Agaricus bisporus Portobello

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    The knowledge about the composition of mushrooms used in food has been increasing in recent years, but their high perishability leads to immediate quality losses after harvesting, which is a drawback for the distribution and marketing of the fresh product. Furthermore, mushrooms have a great popularity all over the world, but data on alternative technologies to increase their shelf life of mushrooms are insufficient. Irradiation is a technique recognized as safe and effective for conservation, and is widely used to extend the shelf life of raw foods. This work evaluates the effects of storage time (ST) (0, 4 and 8 days) and electron-beam (EB) irradiation on fatty acids profile (characterized by GC-FID) of fresh samples of Agaricus bisporus Portobello. The irradiation was performed with a 10 MeV energy irradiator at doses of 1, 2 and 5 kGy. ST and EB irradiation had a cooperative effect (i.e., the interaction among factors was significant, p-value < 0.05) over fatty acids profile. Comparing each factor individually, EB had a more noticeable effect than ST; in fact, the differences among fatty acids percentages for each EB dose were significant in all cases except C18:1n9c (oleic acid), while ST had no significant effects on C12:0, C13:0, C15:0, C18:1n9c, C18:2n6t, C18:3n3, C21:0 and MUFA. Linoleic acid (C18:2n6c) was the most abundant acid (≈78%), presenting slightly higher percentages in mushrooms irradiated with 1 kGy, showing in turn a minor decrease after 8 days of storage. Palmitic acid (≈8%) and stearic acid (≈4%), were the other main fatty acids in A. bisporus. Despite the detected differences, mushrooms presented a similar profile either within different EB doses, as well as along ST. Nevertheless, the 4-days storage maintains the fatty acids profile in higher extent than the 8-days storage; likewise, the best EB dose resulted to be 1 kGy.Foundation for Science and Technology (FCT, Portugal) and FEDER under Programme PT2020 for financial support to CIMO (UID/AGR/00690/2013), C2TN (UID/Multi/04349/2013), A. Fernandes grant (SFRH/BPD/114753/2016) and L. Barros contract; European Structural and Investment Funds (ESIF) (Regional Operational Program Norte 2020, Project ValorNatural®); Rural Development Program (Project MicoCoating, PDR2020-101-031472); International Atomic Energy Agency (IAEA) Coordinated Research Project D61024 DEXAFI.info:eu-repo/semantics/publishedVersio

    Alterations in male rats following in utero exposure to betamethasone suggests changes in reproductive programming

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    Antenatal betamethasone is used for accelerating fetal lung maturation for women at risk of preterm birth. Altered sperm parameters were reported in adult rats after intrauterine exposure to betamethasone. In this study, male rat offspring were assessed for reproductive development after dam exposure to betamethasone (0.1mg/kg) or vehicle on Days 12, 13, 18 and 19 of pregnancy. The treatment resulted in reduction in the offspring body weight, delay in preputial separation, decreased seminal vesicle weight, testosterone levels and fertility, and increased testicular weight. In the testis, morphologically abnormal seminiferous tubules were observed, characterized by an irregular cell distribution with Sertoli cell that were displaced towards the tubular lumen. These cells expressed both Connexin 43 (Cx43) and Proliferative Nuclear Cell Antigen (PCNA). In conclusion, intrauterine betamethasone treatment appears to promote reproductive programming and impairment of rat sexual development and fertility due to, at least in part, unusual testicular disorders

    Using an agent-based model to examine forest management outcomes in a fire-prone landscape in Oregon, USA

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    Fire-prone landscapes present many challenges for both managers and policy makers in developing adaptive behaviors and institutions. We used a coupled human and natural systems framework and an agent-based landscape model to examine how alternative management scenarios affect fire and ecosystem services metrics in a fire-prone multiownership landscape in the eastern Cascades of Oregon. Our model incorporated existing models of vegetation succession and fire spread and information from original empirical studies of landowner decision making. Our findings indicate that alternative management strategies can have variable effects on landscape outcomes over 50 years for fire, socioeconomic, and ecosystem services metrics. For example, scenarios with federal restoration treatments had slightly less high-severity fire than a scenario without treatment; exposure of homes in the wildland-urban interface to fire was also slightly less with restoration treatments compared to no management. Treatments appeared to be more effective at reducing high-severity fire in years with more fire than in years with less fire. Under the current management scenario, timber production could be maintained for at least 50 years on federal lands. Under an accelerated restoration scenario, timber production fell because of a shortage of areas meeting current stand structure treatment targets. Trade-offs between restoration outcomes (e.g., open forests with large fire-resistant trees) and habitat for species that require dense older forests were evident. For example, the proportional area of nesting habitat for northern spotted owl (Strix occidentalis) was somewhat less after 50 years under the restoration scenarios than under no management. However, the amount of resilient older forest structure and habitat for white-headed woodpecker (Leuconotopicus albolarvatus) was higher after 50 years under active management. More carbon was stored on this landscape without management than with management, despite the occurrence of high-severity wildfire. Our results and further applications of the model could be used in collaborative settings to facilitate discussion and development of policies and practices for fire-prone landscapes

    Multiparameter monitoring of Fogo Island, Cape Verde, for volcanic risk mitigation

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    Fogo Island in the Cape Verde Archipelago (North Atlantic) is a stratovolcano of nearly conical shape that rises 2829 m above sea level and 6000 m above the surrounding seafloor. With a population of 40 000, the island has known intense historical volcanic activity since AD 1500, with an average interval between eruptions of the order of 20 years. Twentieth-century rates were more subdued, with only two flank eruptions in 1951 and 1995. Following the 1995 eruption, increased awareness of the volcanic hazard affecting the population of the island led to the deployment of the permanent VIGIL Network. Seismographic stations (both broadband and short-period), tiltmeters and a CO2 sensor where installed in Fogo, together with a telemetry infrastructure to allow remote real-time monitoring. A broadband seismographic station was installed in neighbour Brava Island. The operation of the network was complemented by the introduction of routine geodetic and microgravity surveying and the operation of an automatic meteorological station. In this paper, we describe the methodology adopted to monitor the volcanic activity, combining real-time data analysis (volcanotectonic and volcanic earthquakes, volcanic tremor and tilt) with repeated surveying at intervals of several months (GPS, microgravity). Examples of data from the first years of operation are presented. In particular, the data pertaining to a period of anomalous activity in September–October 2000 are discussed, in the context of the risk mitigation strategy currently being developed
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