193 research outputs found

    No evidence of suitability of prophylactic fluids for wildfire prevention at landscape scales

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    Yu et al. propose a viscoelastic fluid as a prophylactic fire-retardant treatment in landscapes at high risk of wildfires. We argue that, while the idea is worth exploring further, their data do not support its suitability for real landscape-scale applications.Peer reviewe

    Elaeophorosis in Red Deer from Spain

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    Elaeophorosis, caused by Elaeophora elaphi, was observed in red deer (Cervus elaphus) from Toledo Province (Spain) for the first time. Adult specimens of Elaeophora elaphi were found in the hepatic vessels of nine of 151 red deer between October 1994 and September 1995; intensity of infection was two to 18 nematodes per host. Adult nematodes were only found during the period from fall through early spring. No differences were present between sex or age groups. Parasites were not found in a limited sample from fallow deer (Dama dama). Blood samples were negative for the presence of microfilariae

    Forest floor chemical transformations in a boreal forest fire 2 and their correlations with temperature and heating duration 3

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    samples taken pre-and post-fire were characterized using elemental and δ 13 C 24 analysis, differential scanning calorimetry and 13 C nuclear magnetic resonance. 25 During this typical boreal crown fire average maximum temperature (Tmax) at the forest 26 floor was 745 ºC (550<Tmax<976 ºC) with the average heating duration (t) >300 ºC 37 Almost half of the initial total C stock in the forest floor (20 Mg C ha -1 ) was affected b

    Assessing non–parametric estimators of species richness. A case study with birds in green areas of the city of Puebla, Mexico

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    Nuestro objetivo fue evaluar el desempeño de estimadores no paramétricos de la riqueza de especies con datos reales. Durante la temporada de cría de 2003 censamos las comunidades de aves en dos áreas verdes de la ciudad de Puebla (México), y obtuvimos las corres¬pondientes curvas de rarefacción, que fueron ajustadas a dos funciones de acumulación de especies no asintóticas y siete asintóticas. Según criterios de la teoría de la información, la función de acumulación de Weibull o la Beta–P fueron las que mejor describieron estas curvas de acumulación, y asumimos que sus asíntotas estimaron la riqueza real en los dos sitios. Después evaluamos el sesgo, la precisión y la exactitud de cinco estimadores no paramétricos de la riqueza de especies (ICE, Chao 2, Jackknife 1, Jackknife 2 y Bootstrap) para esfuerzos de muestreo crecientes (1–53 unidades de censo). Todos los estimadores no paramétricos aquí evaluados subestimaron la riqueza asintótica la mayor parte del tiempo, en especial en una de las comunidades. Sin embargo, tras combinar los datos de los dos sitios, sólo ICE, Jackknife 1 y Jackknife 2 mostraron sesgos menores al 10% con algún esfuerzo de muestreo, aunque únicamente Jackknife 1 tuvo una exactitud global alta (error medio relativo al cuadradox100 &lt; 5%), incluso con esfuerzos de muestreo bajos (cerca del 20% del total de las unidades de censo). En conclusión, proponemos que el estimador no paramétrico Jackknife 1 puede usarse como un límite inferior de la riqueza de especies de aves en áreas urbanas similares a las de nuestro estudio. Palabras clave: Exactitud, Sesgo, Biodiversidad, Aves, Inventarios, Jackknife, Precisión, Urbanización.Nuestro objetivo fue evaluar el desempeño de estimadores no paramétricos de la riqueza de especies con datos reales. Durante la temporada de cría de 2003 censamos las comunidades de aves en dos áreas verdes de la ciudad de Puebla (México), y obtuvimos las corres¬pondientes curvas de rarefacción, que fueron ajustadas a dos funciones de acumulación de especies no asintóticas y siete asintóticas. Según criterios de la teoría de la información, la función de acumulación de Weibull o la Beta–P fueron las que mejor describieron estas curvas de acumulación, y asumimos que sus asíntotas estimaron la riqueza real en los dos sitios. Después evaluamos el sesgo, la precisión y la exactitud de cinco estimadores no paramétricos de la riqueza de especies (ICE, Chao 2, Jackknife 1, Jackknife 2 y Bootstrap) para esfuerzos de muestreo crecientes (1–53 unidades de censo). Todos los estimadores no paramétricos aquí evaluados subestimaron la riqueza asintótica la mayor parte del tiempo, en especial en una de las comunidades. Sin embargo, tras combinar los datos de los dos sitios, sólo ICE, Jackknife 1 y Jackknife 2 mostraron sesgos menores al 10% con algún esfuerzo de muestreo, aunque únicamente Jackknife 1 tuvo una exactitud global alta (error medio relativo al cuadradox100 &lt; 5%), incluso con esfuerzos de muestreo bajos (cerca del 20% del total de las unidades de censo). En conclusión, proponemos que el estimador no paramétrico Jackknife 1 puede usarse como un límite inferior de la riqueza de especies de aves en áreas urbanas similares a las de nuestro estudio. Palabras clave: Exactitud, Sesgo, Biodiversidad, Aves, Inventarios, Jackknife, Precisión, Urbanización.Our objective was to evaluate the performance of non–parametric estimators of spe¬cies richness with real data. During the 2003 breeding season, bird communities were sampled in two green areas in the city of Puebla (Mexico), and the corresponding sample–based rarefaction curves were obtained. Mean data were adjusted to two non–asymptotic and seven asymptotic accumulation functions, and the best model was selected by means of reliability criteria in information theory. The cumulative Weibull and the Beta–P functions were the best–fit models. Bias, precision and accuracy of five non–parametric estimators of species richness (ICE, Chao2, Jackknife 1, Jackknife 2, and Bootstrap) were then assessed for increasing sampling efforts (1–53 sampling units) against the asymptote of the selected accumulation functions. All the non–parametric estimators here evaluated underestimated true richness most of the time, specially in one of the sites. However, after combining data from the two assemblages, only ICE, and Jackknife 1 and 2 exhibited bias below 10% with different sampling efforts, and only Jackknife 1 was globally accurate (scaled mean squared errorx100< 5%, even with low sampling efforts, ca. 20% of the total). Therefore, we propose using the Jackknife 1 non–parametric estimator as a lower limit to measure bird species richness in urban sites similar to those in the present study. Key words: Accuracy, Bias, Biodiversity, Birds, Inventories, Jackknife, Precision, Urbanization

    Weed control options in conventional and GM maize

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    En el proyecto AMIGA, que estudia los posibles efectos de los cultivos modificados genéticamente y su manejo sobre el agro-eco-sistema y la biodiversidad, se han evaluado varios tratamientos herbicidas sobre maíz Bt y maíz convencional. Se estableció un ensayo de seis hectáreas durante dos años en el que se han utilizado cinco manejos con herbicida que incluyen tratamiento convencional, reducido, glifosato y dos combinaciones de los anteriores. Se muestreó a lo largo del desarrollo del cultivo para determinar las especies de malas hierbas y artrópodos en el tiempo así como su abundancia y diversidad mediante examen visual y uso de trampas de gravedad y adhesivas amarillas. En este trabajo se presentan datos de abundancia de malas hierbas a madurez fisiológica del cultivo y del total de artrópodos en muestreo visual.Effect on weeds and arthropods In the context of AMIGA project which studies the posible effects of genetically modified crops and their management on the agro-ecosystem and biodiversity, we have studied various herbicide treatments applied on conventional and Bt A field was conducted for two years in a six ha plot. Five herbicide treatments including conventional, reduced, glyphosate and two herbicides combinations were established. We sampled along the cropping period to determine the species of weeds and arthropods over time and their abundance and diversity. The presence of arthropods was determined by visual examination and the use of pitfall and yellow sticky traps. In this work whole abundance of weeds at physiological maturity of the crop and total abundance of arthropod in visual examination are presented

    Co-Infection with Cryptosporidium meleagridis and Enterocytozoon bieneusi in an HIV+ Colombian Patient

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    A 44-year-old human immunodeficiency virus-infected (HIV+) female with severe immunodeficiency Category 3 (C3) diagnosed in 2010 was admitted to hospital with acute diarrhoea. She was non-adherent to antiretroviral therapy (ART) and had a previous suspicion of respiratory symptoms with a cough that had been persisting for 15 days. Clinical examination revealed severe immune deterioration (viral load: 109,655 copies/mL; CD4+ count: 14 cells/mm3), respiratory symptoms (negative sputum Gram stain and tuberculosis culture), and neurological deterioration (serological assays negative for Cryptococcus spp. and Toxoplasma gondii). A coproculture was negative for Campylobacter spp., Salmonella spp., and Shigella spp. Ziehl–Neelsen staining of faecal smears revealed the presence of Cryptosporidium spp. oocysts. PCR testing and sequencing confirmed a concomitant infection with C. meleagridis and Enterocytozoon bieneusi. The patient was treated with metronidazole (500 mg every 8 h for 5 days) and nitazoxanide (500 mg every 12 h for 14 days). After requesting voluntary discharge and abandoning ART and parasiticidal treatments, she experienced a dramatic deterioration of her state of health and contact with her was lost. Our results have demonstrated that molecular-based testing improves the detection of opportunistic pathogens that are difficult to detect by routine microscopy, allows for transmission dynamics investigations, and assists in choosing the best chemotherapeutical option.This research was funded by the Health Institute Carlos III (ISCIII) and the Ministry of Economy and Competitiveness (Spain) under project PI16CIII/00024.S

    Carbon sequestration potential and physicochemical properties differ between wildfire charcoals and slow-pyrolysis biochars

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    Pyrogenic carbon (PyC), produced naturally (wildfire charcoal) and anthropogenically (biochar), is extensively studied due to its importance in several disciplines, including global climate dynamics, agronomy and paleosciences. Charcoal and biochar are commonly used as analogues for each other to infer respective carbon sequestration potentials, production conditions, and environmental roles and fates. The direct comparability of corresponding natural and anthropogenic PyC, however, has never been tested. Here we compared key physicochemical properties (elemental composition, δ13C and PAHs signatures, chemical recalcitrance, density and porosity) and carbon sequestration potentials of PyC materials formed from two identical feedstocks (pine forest floor and wood) under wildfire charring- and slow-pyrolysis conditions. Wildfire charcoals were formed under higher maximum temperatures and oxygen availabilities, but much shorter heating durations than slow-pyrolysis biochars, resulting in differing physicochemical properties. These differences are particularly relevant regarding their respective roles as carbon sinks, as even the wildfire charcoals formed at the highest temperatures had lower carbon sequestration potentials than most slow-pyrolysis biochars. Our results challenge the common notion that natural charcoal and biochar are well suited as proxies for each other, and suggest that biochar’s environmental residence time may be underestimated when based on natural charcoal as a proxy, and vice versa

    The Relevance of Pyrogenic Carbon for Carbon Budgets From Fires: Insights From the FIREX Experiment

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    Vegetation fires play an important role in global and regional carbon cycles. Due to climate warming and land use shifts, fire patterns are changing and fire impacts increasing in many of the world's regions. Reducing uncertainties in carbon budgeting calculations from fires is therefore fundamental to advance our current understanding and forecasting capabilities. Here we study 20 chamber burns from the FIREX FireLab experiment, which burnt a representative set of North American wildland fuels, to assess the following: (i) differences in carbon emission estimations between the commonly used “consumed biomass” approach and the “burnt carbon” approach; (ii) pyrogenic carbon (PyC) production rates; and (iii) thermal and chemical recalcitrance of the PyC produced, as proxies of its biogeochemical stability. We find that the “consumed biomass” approach leads to overestimation of carbon emissions by 2–27% (most values between 2% and 10%). This accounting error arises largely from not considering PyC production and, even if relatively small, can therefore have important implications for medium‐ and long‐term carbon budgeting. A large fraction (34–100%) of this PyC was contained in the charred fine residue, a postfire material frequently overlooked in fire carbon research. However, the most recalcitrant PyC was in the form of woody charcoal, with estimated half‐lives for most samples exceeding 1,000 years. Combustion efficiency was relatively high in these laboratory burns compared to actual wildland fire conditions, likely leading to lower PyC production rates. We therefore argue that the PyC production values obtained here, and associated overestimation of carbon emissions, should be taken as low‐end estimates for wildland fire conditions

    Global fire emissions buffered by the production of pyrogenic carbon

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    Landscape fires burn 3–5 million km2 of the Earth’s surface annually. They emit 2.2 Pg of carbon per year to the atmosphere, but also convert a significant fraction of the burned vegetation biomass into pyrogenic carbon. Pyrogenic carbon can be stored in terrestrial and marine pools for centuries to millennia and therefore its production can be considered a mechanism for long-term carbon sequestration. Pyrogenic carbon stocks and dynamics are not considered in global carbon cycle models, which leads to systematic errors in carbon accounting. Here we present a comprehensive dataset of pyrogenic carbon production factors from field and experimental fires and merge this with the Global Fire Emissions Database to quantify the global pyrogenic carbon production flux. We found that 256 (uncertainty range: 196–340) Tg of biomass carbon was converted annually into pyrogenic carbon between 1997 and 2016. Our central estimate equates to 12% of the annual carbon emitted globally by landscape fires, which indicates that their emissions are buffered by pyrogenic carbon production. We further estimate that cumulative pyrogenic carbon production is 60 Pg since 1750, or 33–40% of the global biomass carbon lost through land use change in this period. Our results demonstrate that pyrogenic carbon production by landscape fires could be a significant, but overlooked, sink for atmospheric CO2

    Advances in prevention and therapy of neonatal dairy calf diarrhoea : a systematical review with emphasis on colostrum management and fluid therapy

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    Neonatal calf diarrhoea remains the most common cause of morbidity and mortality in preweaned dairy calves worldwide. This complex disease can be triggered by both infectious and non-infectious causes. The four most important enteropathogens leading to neonatal dairy calf diarrhoea are Escherichia coli, rota-and coronavirus, and Cryptosporidium parvum. Besides treating diarrhoeic neonatal dairy calves, the veterinarian is the most obvious person to advise the dairy farmer on prevention and treatment of this disease. This review deals with prevention and treatment of neonatal dairy calf diarrhoea focusing on the importance of a good colostrum management and a correct fluid therapy
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