11 research outputs found

    Water and energy fluxes from a woodland savanna (cerrado) in southeast Brazil

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    Study region: The area of woodland savanna (cerrado) is located in southeast Brazil (21°36′ to 44′ S, 47°34′ to 41′ W). Study focus: The cerrado sensu-stricto savanna evapotranspiration was observed using the eddy-covariance method over three years. New hydrological insights for the region: The first year total rainfall (R = 1664 mm) was 11% above the long-term rainfall (1498 mm) and the total evapotranspiration (ET = 1242 mm) and water equivalent of available energy (Av = 1835 mm) were approximately 4% and 2% greater, respectively, than in the second year when the rainfall total was 5% lower than the long-term average. In the third year despite the total rainfall (1259 mm) being 24% lower than the first year and 16% lower than the average, the totals of ET (1242 mm) and Av (1815 mm) were approximately the same. The small variation in the observed annual ET totals shows that in this cerrado vegetation the deep soil moisture content supports the ET in a dry year and the water available for recharging the soil profile and groundwater (∼R − ET) was dominated by the rainfall amount being significantly greater in the wet year (422 mm) than in the dry year (13 mm)

    Environmental assessment of industrial production of microalgal biodiesel in central-south Chile

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    Biofuels from microalgae have the potential to replace fossil fuels, without competing with other products derived from crops. This study aims to perform a cradle-to-gate Life Cycle Assessment of the industrial production of microalgal biodiesel, using an autochthonous Chilean Phaeodactylum tricornutum strain, considering 1 MJ of biodiesel as the functional unit. For the compilation of the Life Cycle Inventory, real experimental data were obtained from the pilot-scale cultivation in a photobioreactor (PBR) module located in the city of Concepción, in Chile. The scale-up to the industrial plant considers that PBR modules are of the same size as those used in the pilot-scale. The Life Cycle Impacts Analysis considered the ReCiPe 2016 Endpoint (H) V1.00 method. Results show that the whole process contributes to a total of 5.74 kgCO2eq per MJ of biodiesel produced. PBR construction materials and energy consumption are the main contributors to the life cycle environmental impacts. The sensitivity analysis shows that energy consumption, water reuse and transportation distance of seawater from ocean to the industrial plant are the critical parameters that most affect the overall environmental performance of the system. The rate of water reuse is particularly critical to the global warming potential. Results also show that the valorization of co-products is an important aspect to improve the environmental performance of microalgal biodiesel production. Therefore, this study supports the decision-making process in biofuel production to promote the development of sustainable pilot and large-scale algae-based industry.publishe

    Large expert-curated database for benchmarking document similarity detection in biomedical literature search

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    Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe

    Biotechnological potential of Phaeodactylum tricornutum for biorefinery processes

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    Microalgae are a rich source of proteins, carbohydrates and lipids, among other components, and thus, are considered to be the next generation biomass. However, in order to enhance the economic viability of its industrial production, all biomass components need to be valorized, requiring a multi-product biorefinery. Thus, this work proposes and conceptually analyses biorefinery processes for valorizing Phaeodactylum tricornutum for biofuels and high-value compounds, based on real data from a pilot-scale process. The algal biomass was biochemically characterized and the production was scaled-up to an industrial approach to analyze three biorefinery configurations, based on a 18 ton·year−1 of microalga biomass. The biomass revealed a composition of 7.85 wt% carbohydrates, 38.40 wt% proteins, 9.08 wt% lipids, 0.86 wt% fucoxanthin and 5.19 wt% biosilica. The biorefinery process addressed for biofuels production has an estimated annual production of 1.72, 0.35 and 1361 m3·year−1 of respectively biodiesel, bioethanol and biomethane. The biorefinery addressed for high-value compounds yields 0.18, 0.93 and 6.95 ton·year−1 of respectively fucoxanthin, biosilica and protein. The biorefinery designed for valorizing full microalgae biomass, showed to be more beneficial for promoting a circular economy. Biorefinery approach is useful for making sound and profitable decisions regarding microalgae bioproducts.info:eu-repo/semantics/publishedVersio

    Fluxes of CO2 above a plantation of Eucalyptus in southeast Brazil

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    Eddy-covariance measurements of net ecosystem exchange of CO2 (NEE) and estimates of gross ecosystem productivity (GEP) and ecosystem respiration (RE) were obtained in a 2–4 year old Eucalyptus plantation during two years with very different winter rainfall. In the first (drier) year the annual NEE, GEP and RE were lower than the sums in the second (normal) year, and conversely the total respiratory costs of assimilated carbon were higher in the dry year than in the normal year. Although the net primary production (NPP) in the first year was 23% lower than that of the second year, the decrease in the carbon use efficiency (CUE = NPP/GEP) was 11% and autotrophic respiration utilized more resources in the first, dry year than in the second, normal year. The time variations in NEE were followed by NPP, because in these young Eucalyptus plantations NEE is very largely dominated by NPP, and heterotrophic respiration plays only a relatively minor role. During the dry season a pronounced hysteresis was observed in the relationship between NEE and photosynthetically active radiation, and NEE fluxes were inversely proportional to humidity saturation deficit values greater than 0.8 kPa. Nighttime fluxes of CO2 during calm conditions when the friction velocity (u*) was below the threshold (0.25 m s−1) were estimated based on a Q10 temperature-dependence relationship adjusted separately for different classes of soil moisture content, which regulated the temperature sensitivity of ecosystem respiratio

    Avaliação dos fatores oficiais de correção da produção até o primeiro controle leiteiro em vacas Holandesas Evaluation of correction factors used to estimate milk production from calving to the first monthly control

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    Para o cálculo oficial do desempenho de vacas Holandesas no Brasil, com base em controles leiteiros mensais, são utilizados os fatores de correção propostos por Everett & Carter (1968) para estimar a produção parcial do parto ao primeiro controle diário de uma dada lactação. A adequacidade destes fatores foi avaliada em 262 lactações oriundas de dois rebanhos que adotavam controle diário da produção de leite por vaca. Os dados foram divididos em classes com base na idade ao parto (CIP): CIP 1 (até 3 anos), CIP 2 (3,1 a 4 anos), CIP 3 (4,1 a 5 anos), CIP 4 (5,1 a 6 anos) e CIP 5 (acima de 6,1 anos) com 104, 56, 44, 18 e 40 lactações, respectivamente. A produção de leite do parto até um dia pré-definido da lactação foi estimada com os fatores oficiais e assumindo que o primeiro controle da produção naquela lactação ocorreu nos dias 6º, 20º, 34º, 48º, 62º ou 75º. Os dados estimados foram comparados aos dados reais calculados com a pesagem diária do leite. Em todas as CIP, os fatores oficiais superestimaram a produção acumulada até o primeiro controle e o erro relativo de superestimação decresceu com o avançar do dia do primeiro controle. A quantidade superestimada de leite no período aumentou com o avançar do dia do primeiro controle e foi 13,9 e 87,1 kg na CIP 1 e 20,6 e 196,3 kg na CIP 2 para os dias 6º e 75º, respectivamente. As CIPs 3, 4 e 5 apresentaram valores intermediários. Novos fatores para dias do primeiro controle variando de 6 a 75 e nas 5 CIPs foram gerados pela mesma metodologia descrita por Everett & Carter (1968). Os fatores gerados foram menores que os importados e rotineiramente utilizados para cálculo oficial de lactações no Brasil.<br>Official Holstein cow performance data in Brazil, based on monthly milk weights, is calculated using the correction factors proposed by Everett & Carter (1968) to estimate the partial production from calving to the first daily control in a given lactation. The adequacy of these factors was evaluated using 262 lactations from two herds with daily control of milk production per cow. Data were divided into classes based on age at calving (CIP): CIP 1 (up to 3 years), CIP 2 (3.1 to 4 years), CIP 3 (4.1 to 5 years), CIP 4 (5.1 to 6 years) and CIP 5 (above 6.1 years) which included 104, 56, 44, 18 and 40 lactations, respectively. Milk yield from calving to a set day of lactation was estimated with the official factors and assuming that the first control of production of that given lactation occurred on days 6th, 20th, 34th, 48th, 62nd or 75th. Estimated data was compared with real data calculated from daily milk weights. For all CIPs, official factors overestimated the production from calving to first control and the relative overestimation error decreased with advance in the first control day. The overestimated amount of milk in that period increased with advance in the first control day and was 13.9 and 87.1 kg in CIP 1 and 20.6 and 196.3 kg in CIP 2 for days 6th and 75th, respectively. CIPs 3, 4, and 5 had intermediate values. New factors for first control days ranging from 6 to 75 and in all 5 CIPs were generated using the same methodology described by Everett & Carter (1968). The generated factors were smaller than the ones imported and routinely used to calculate official lactation records in Brazil

    The impact of the method of consent on response rates in the ISAAC time trends study

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    BACKGROUND: Centres in Phases I and III of the International Study of Asthma and Allergies in Childhood (ISAAC) programme used the method of consent (passive or active) required by local ethics committees. METHODS: Retrospectively, relationships between achieved response rates and method of consent for 13-14 and 6-7-year-olds (adolescents and children, respectively), were examined between phases and between English and non-English language centres. RESULTS: Information was obtained for 113 of 115 centres for adolescents and 72/72 centres for children. Both age groups: most centres using passive consent achieved high response rates (>80% adolescents and >70% children). English language centres using active consent showed a larger decrease in response rate. Adolescents: seven centres changed from passive consent in Phase I to active consent in Phase III (median decrease of 13%), with five centres showing lower response rates (as low as 34%). Children: no centre changed consent method between phases. Centres using active consent had lower median response rates (lowest response rate 45%). CONCLUSION: The requirement for active consent for population school-based questionnaire studies can impact negatively on response rates, particularly English language centres, thus adversely affecting the validity of the data. Ethics committees need to consider this issue carefully. © 2010 The Union

    Growing knowledge: an overview of Seed Plant diversity in Brazil

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    Growing knowledge: an overview of Seed Plant diversity in Brazil

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    Abstract An updated inventory of Brazilian seed plants is presented and offers important insights into the country's biodiversity. This work started in 2010, with the publication of the Plants and Fungi Catalogue, and has been updated since by more than 430 specialists working online. Brazil is home to 32,086 native Angiosperms and 23 native Gymnosperms, showing an increase of 3% in its species richness in relation to 2010. The Amazon Rainforest is the richest Brazilian biome for Gymnosperms, while the Atlantic Rainforest is the richest one for Angiosperms. There was a considerable increment in the number of species and endemism rates for biomes, except for the Amazon that showed a decrease of 2.5% of recorded endemics. However, well over half of Brazillian seed plant species (57.4%) is endemic to this territory. The proportion of life-forms varies among different biomes: trees are more expressive in the Amazon and Atlantic Rainforest biomes while herbs predominate in the Pampa, and lianas are more expressive in the Amazon, Atlantic Rainforest, and Pantanal. This compilation serves not only to quantify Brazilian biodiversity, but also to highlight areas where there information is lacking and to provide a framework for the challenge faced in conserving Brazil's unique and diverse flora
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