Comparação entre Algoritmos de Aprendizado de Máquina para a Identificação de Floresta Tropical Sazonalmente Seca

O objetivo do estudo foi avaliar o potencial dos algoritmos de aprendizado de máquina k-Nearest Neighbor (kNN), Random Forest (RF), Support Vector Machine (SVM) e Artificial Neural Networks (ANN) na identificação das fitofisionomias da Caatinga a partir de imagens OLI/Landsat 8. Para tanto, foi elaborado um arquivo vetorial de treinamento com as amostras dos diferentes padrões dos usos e cobertura da terra, a fim de orientar os algoritmos no processo de classificação. A validação das classificações foi obtida por meio da validação cruzada, do tipo k-fold, com 30 repetições, sendo avaliada a qualidade da classificação a partir dos valores expressos pelo coeficiente Kappa. Para verificar a existência de diferenças significativas entre os algoritmos foi aplicado o teste estatístico de Friedman e Nemenyi. O algoritmo RF apresentou os maiores valores para o coeficiente Kappa, expressando um valor médio de 0,9841. Por outro lado, a ANN demonstrou desempenho inferior aos demais, englobando um valor médio de 0,7551, ocasionado pela confusão espectral na identificação da classe nuvem/sombra com a classe água. Apesar de todos os algoritmos testados apresentarem bons resultados, o algoritmo RF diferiu significativamente dos demais, expressando resultados superiores quando aplicado à identificação de padrões espaciais na Caatinga. Conclui-se que o uso de algoritmos de aprendizagem de máquina é eficiente na identificação de fitofisionomias da Caatinga, com destaque para o RF, o qual englobou melhor a variação dos padrões espectrais dos usos, podendo ser utilizado para estudos posteriores relacionados com a Caatinga.

Comparison Between Three Methods to Monitor Reservoir Extension in the Brazilian Semi-Arid Region

The State of Pernambuco covers an extensive semi-arid area where the Caatinga biome dominates. This region is characterized by long periods of drought, highlighting the need for water resource optimization. This paper aimed to compare three methods to assess reservoir changes: MapBiomas' products, the Normalized Difference Water Index (NDWI), and a support vector machine (SVM) algorithm. Initially, we obtained the monthly precipitation from 1987 to 2019 and calculated the yearly accumulation. Mapbiomas, Landsat 7 ETM, and Landsat 8 OLI data from 2012-2018 were accessed and processed using the Google Earth Engine platform. We obtained the annual image with the median pixel criterion to determine the NDWI and quantify the annual reservoir area. For the supervised classification with SVM, samples from different land-use types of the study area were used to train the algorithm. From 2012 to 2018, a reservoir reduction of 63.42% was observed with MapBiomas images, 69.49% with NDWI images, and 67.69% using the SVM algorithm. The results obtained using NDWI were the most similar to those from the artificial intelligence classification, indicating that NDWI can be used to monitor the reservoir conditions

Características agronômicas e sensibilidade ao rachamento de bagas de uvas sem sementes

As variedades de uvas sem sementes apresentam maior dificuldades de adaptação às condições tropicais do semiárido nordestino, exibindo produções reduzidas e irregulares, resultado de sua baixa fertilidade de gemas, desgrane elevado e suscetibilidade à rachadura de bagas. O objetivo deste trabalho foi avaliar aspectos relacionados à susceptibilidade ao rachamento e podridão de bagas e características agronômicas de uvas sem sementes sob as condições do Submédio do Vale São Francisco. Para isso, o experimento foi conduzido no Campo Experimental de Bebedouro na Embrapa Semiárido, em Petrolina-PE. Foram avaliadas cinco variedades ao longo de dois ciclos de produção, correspondendo aos anos de 2013 e 2014. Utilizaram-se as variedades Adona, BRS Clara, BRS Maria Bonita, Arizul e Thompson Seedless, nas quais foram determinadas as seguintes variáveis: produção (Kg planta-1), número de cachos, massa do cacho (g); teor de sólidos solúveis (oBrix) e acidez titulável (g de ácido tartárico 100mL-1); bagas rachadas (%) e bagas podres (%). Os resultados mostraram que tanto o percentual de rachamento quanto o de podridão apontaram para as variedades BRS Clara e Adona como as mais tolerantes e a variedade Thompson Seedless como a mais suscetível. A maior produção por planta foi obtida no Ciclo 2 para a variedade BRS Clara (20,63 Kg planta-1), seguida da Adona (17,52 Kg planta-1. Assim, as variedades BRS clara e Adona destacaram-se com melhores características de qualidade e maior tolerância à rachadura e podridões de bagas, apresentando potencial para produção de duas safras ao ano no Submédio do Vale São Francisco

Tratamentos pré-germinativos em sementes de espécies da Caatinga

Algumas espécies da Caatinga apresentam sementes com dormência, um mecanismo que permite a germinação quando as condições ambientais propiciarem seu estabelecimento e sobrevivência; esta característica é vantajosa para a perpetuação e indesejável para os produtores que necessitam de uma rápida produção destas plantas. O estudo objetivou avaliar a eficiência da aplicação de tratamentos pré-germinativos em sementes de Angico (Anadenanthera colubrina) (Vell.) Brenan, Jurema-branca (Piptadenia stipulacea) (Benth.) Ducke e Mulungu (Erythrina velutina Willd.). Foram conduzidos dois experimentos independentes na Unidade Acadêmica de Serra Talhada. Sementes de Angico, Jurema-branca e Mulungu foram dispostas em delineamento experimental inteiramente casualizado, com quatro repetições e 15 sementes. Foram aplicados os tratamentos pré-germinativos: T1-testemunha, T2-escarificação mecânica em extremidade oposta ao hilo com lixa de madeira, T3-escarificação mecânica em extremidade oposta ao hilo com lixa de madeira + imersão em água sob temperatura ambiente por 24 horas e T4-tratamento térmico com imersão em água a 80ºC por 2 minutos. A eficiência foi avaliada pelos parâmetros: porcentagem de germinação e índice de velocidade de emergência (IVE), dados biométricos (30 dias após a semeadura), como altura das plântulas, número de folhas e diâmetro do coleto. As sementes de Jurema-branca (P. stipulacea) e Mulungu (E. velutina), submetidas aos tratamentos pré-germinativos T2 e T3, apresentaram melhores desempenhos germinativos, refletidos no crescimento da plântula. O Angico (A. colubrina) não se mostrou sensível à aplicação dos tratamentos e a germinação foi anulada em decorrência da aplicação do tratamento T3. Em todos os casos foram observadas variações nos parâmetros em decorrência, possivelmente, das condições atmosféricas

Índices morfofisiológicos e biofísicos da palma forrageira cultivada sob tecnologias hídricas na bacia do Rio Pajeú

Estima-se que metade da superfície da Caatinga já foi modificada. A remoção da vegetação aumenta a fragilidade das terras e intensifica o processo de desertificação. Sob condições de aporte hídrico variado, a adoção de tecnologias hídricas é indicada. As características morfofisiológicas e biofísicas da palma forrageira foram investigadas neste estudo como indicativo à adequação do manejo da cultura sob diferentes tecnologias hídricas (clones, irrigação e cobertura morta). O experimento foi conduzido em blocos casualizados, com três repetições, e sob três ambientes de crescimento com uma ou mais tecnologias hídricas: RH(-) - clones sob regime hídrico inferior à normal climatológica (sequeiro); RH(+) - clones sob regime hídrico superior à normal climatológica (irrigado); e, RH(+C) - clones sob regime hídrico superior à normal climatológica (irrigado) e adoção de cobertura morta. Os clones avaliados foram: IPA Sertânia e Miúda, e Orelha de Elefante Mexicana. Medidas biométricas foram obtidas ao longo do tempo e a matéria seca na ocasião da colheita, a partir dos quais, calculou-se índices morfofisiológicos e biofísicos. Os ambientes de crescimento e sua interação com os clones afetaram apenas a magnitude do índice de distribuição dos cladódios de 5ª ordem (p < 0,05), mas foram decisivos na sazonalidade do acúmulo de matéria seca pelos clones. A maioria dos índices morfofisiológicos e biofísicos foi influenciada pelo tipo de clone (p < 0,05). Os índices biofísicos se mostram ótimas opções de substituição ou complementação dos índices morfofisiológicos quando se dispõem apenas de dados biométricos e de matéria seca da ocasião da colheita da palma forrageira

Height and body-mass index trajectories of school-aged children and adolescents from 1985 to 2019 in 200 countries and territories: a pooled analysis of 2181 population-based studies with 65 million participants

Summary Background Comparable global data on health and nutrition of school-aged children and adolescents are scarce. We aimed to estimate age trajectories and time trends in mean height and mean body-mass index (BMI), which measures weight gain beyond what is expected from height gain, for school-aged children and adolescents. Methods For this pooled analysis, we used a database of cardiometabolic risk factors collated by the Non-Communicable Disease Risk Factor Collaboration. We applied a Bayesian hierarchical model to estimate trends from 1985 to 2019 in mean height and mean BMI in 1-year age groups for ages 5–19 years. The model allowed for non-linear changes over time in mean height and mean BMI and for non-linear changes with age of children and adolescents, including periods of rapid growth during adolescence. Findings We pooled data from 2181 population-based studies, with measurements of height and weight in 65 million participants in 200 countries and territories. In 2019, we estimated a difference of 20 cm or higher in mean height of 19-year-old adolescents between countries with the tallest populations (the Netherlands, Montenegro, Estonia, and Bosnia and Herzegovina for boys; and the Netherlands, Montenegro, Denmark, and Iceland for girls) and those with the shortest populations (Timor-Leste, Laos, Solomon Islands, and Papua New Guinea for boys; and Guatemala, Bangladesh, Nepal, and Timor-Leste for girls). In the same year, the difference between the highest mean BMI (in Pacific island countries, Kuwait, Bahrain, The Bahamas, Chile, the USA, and New Zealand for both boys and girls and in South Africa for girls) and lowest mean BMI (in India, Bangladesh, Timor-Leste, Ethiopia, and Chad for boys and girls; and in Japan and Romania for girls) was approximately 9–10 kg/m2. In some countries, children aged 5 years started with healthier height or BMI than the global median and, in some cases, as healthy as the best performing countries, but they became progressively less healthy compared with their comparators as they grew older by not growing as tall (eg, boys in Austria and Barbados, and girls in Belgium and Puerto Rico) or gaining too much weight for their height (eg, girls and boys in Kuwait, Bahrain, Fiji, Jamaica, and Mexico; and girls in South Africa and New Zealand). In other countries, growing children overtook the height of their comparators (eg, Latvia, Czech Republic, Morocco, and Iran) or curbed their weight gain (eg, Italy, France, and Croatia) in late childhood and adolescence. When changes in both height and BMI were considered, girls in South Korea, Vietnam, Saudi Arabia, Turkey, and some central Asian countries (eg, Armenia and Azerbaijan), and boys in central and western Europe (eg, Portugal, Denmark, Poland, and Montenegro) had the healthiest changes in anthropometric status over the past 3·5 decades because, compared with children and adolescents in other countries, they had a much larger gain in height than they did in BMI. The unhealthiest changes—gaining too little height, too much weight for their height compared with children in other countries, or both—occurred in many countries in sub-Saharan Africa, New Zealand, and the USA for boys and girls; in Malaysia and some Pacific island nations for boys; and in Mexico for girls. Interpretation The height and BMI trajectories over age and time of school-aged children and adolescents are highly variable across countries, which indicates heterogeneous nutritional quality and lifelong health advantages and risks

Worldwide trends in underweight and obesity from 1990 to 2022: a pooled analysis of 3663 population-representative studies with 222 million children, adolescents, and adults

Background Underweight and obesity are associated with adverse health outcomes throughout the life course. We estimated the individual and combined prevalence of underweight or thinness and obesity, and their changes, from 1990 to 2022 for adults and school-aged children and adolescents in 200 countries and territories. Methods We used data from 3663 population-based studies with 222 million participants that measured height and weight in representative samples of the general population. We used a Bayesian hierarchical model to estimate trends in the prevalence of different BMI categories, separately for adults (age ≥20 years) and school-aged children and adolescents (age 5–19 years), from 1990 to 2022 for 200 countries and territories. For adults, we report the individual and combined prevalence of underweight (BMI <18·5 kg/m2) and obesity (BMI ≥30 kg/m2). For schoolaged children and adolescents, we report thinness (BMI <2 SD below the median of the WHO growth reference) and obesity (BMI >2 SD above the median). Findings From 1990 to 2022, the combined prevalence of underweight and obesity in adults decreased in 11 countries (6%) for women and 17 (9%) for men with a posterior probability of at least 0·80 that the observed changes were true decreases. The combined prevalence increased in 162 countries (81%) for women and 140 countries (70%) for men with a posterior probability of at least 0·80. In 2022, the combined prevalence of underweight and obesity was highest in island nations in the Caribbean and Polynesia and Micronesia, and countries in the Middle East and north Africa. Obesity prevalence was higher than underweight with posterior probability of at least 0·80 in 177 countries (89%) for women and 145 (73%) for men in 2022, whereas the converse was true in 16 countries (8%) for women, and 39 (20%) for men. From 1990 to 2022, the combined prevalence of thinness and obesity decreased among girls in five countries (3%) and among boys in 15 countries (8%) with a posterior probability of at least 0·80, and increased among girls in 140 countries (70%) and boys in 137 countries (69%) with a posterior probability of at least 0·80. The countries with highest combined prevalence of thinness and obesity in school-aged children and adolescents in 2022 were in Polynesia and Micronesia and the Caribbean for both sexes, and Chile and Qatar for boys. Combined prevalence was also high in some countries in south Asia, such as India and Pakistan, where thinness remained prevalent despite having declined. In 2022, obesity in school-aged children and adolescents was more prevalent than thinness with a posterior probability of at least 0·80 among girls in 133 countries (67%) and boys in 125 countries (63%), whereas the converse was true in 35 countries (18%) and 42 countries (21%), respectively. In almost all countries for both adults and school-aged children and adolescents, the increases in double burden were driven by increases in obesity, and decreases in double burden by declining underweight or thinness. Interpretation The combined burden of underweight and obesity has increased in most countries, driven by an increase in obesity, while underweight and thinness remain prevalent in south Asia and parts of Africa. A healthy nutrition transition that enhances access to nutritious foods is needed to address the remaining burden of underweight while curbing and reversing the increase in obesit

Rationale, study design, and analysis plan of the Alveolar Recruitment for ARDS Trial (ART): Study protocol for a randomized controlled trial

Background: Acute respiratory distress syndrome (ARDS) is associated with high in-hospital mortality. Alveolar recruitment followed by ventilation at optimal titrated PEEP may reduce ventilator-induced lung injury and improve oxygenation in patients with ARDS, but the effects on mortality and other clinical outcomes remain unknown. This article reports the rationale, study design, and analysis plan of the Alveolar Recruitment for ARDS Trial (ART). Methods/Design: ART is a pragmatic, multicenter, randomized (concealed), controlled trial, which aims to determine if maximum stepwise alveolar recruitment associated with PEEP titration is able to increase 28-day survival in patients with ARDS compared to conventional treatment (ARDSNet strategy). We will enroll adult patients with ARDS of less than 72 h duration. The intervention group will receive an alveolar recruitment maneuver, with stepwise increases of PEEP achieving 45 cmH(2)O and peak pressure of 60 cmH2O, followed by ventilation with optimal PEEP titrated according to the static compliance of the respiratory system. In the control group, mechanical ventilation will follow a conventional protocol (ARDSNet). In both groups, we will use controlled volume mode with low tidal volumes (4 to 6 mL/kg of predicted body weight) and targeting plateau pressure <= 30 cmH2O. The primary outcome is 28-day survival, and the secondary outcomes are: length of ICU stay; length of hospital stay; pneumothorax requiring chest tube during first 7 days; barotrauma during first 7 days; mechanical ventilation-free days from days 1 to 28; ICU, in-hospital, and 6-month survival. ART is an event-guided trial planned to last until 520 events (deaths within 28 days) are observed. These events allow detection of a hazard ratio of 0.75, with 90% power and two-tailed type I error of 5%. All analysis will follow the intention-to-treat principle. Discussion: If the ART strategy with maximum recruitment and PEEP titration improves 28-day survival, this will represent a notable advance to the care of ARDS patients. Conversely, if the ART strategy is similar or inferior to the current evidence-based strategy (ARDSNet), this should also change current practice as many institutions routinely employ recruitment maneuvers and set PEEP levels according to some titration method.Hospital do Coracao (HCor) as part of the Program 'Hospitais de Excelencia a Servico do SUS (PROADI-SUS)'Brazilian Ministry of Healt

Heterogeneous contributions of change in population distribution of body mass index to change in obesity and underweight NCD Risk Factor Collaboration (NCD-RisC)

From 1985 to 2016, the prevalence of underweight decreased, and that of obesity and severe obesity increased, in most regions, with significant variation in the magnitude of these changes across regions. We investigated how much change in mean body mass index (BMI) explains changes in the prevalence of underweight, obesity, and severe obesity in different regions using data from 2896 population-based studies with 187 million participants. Changes in the prevalence of underweight and total obesity, and to a lesser extent severe obesity, are largely driven by shifts in the distribution of BMI, with smaller contributions from changes in the shape of the distribution. In East and Southeast Asia and sub-Saharan Africa, the underweight tail of the BMI distribution was left behind as the distribution shifted. There is a need for policies that address all forms of malnutrition by making healthy foods accessible and affordable, while restricting unhealthy foods through fiscal and regulatory restrictions

Seasonal analysis of CO 2 fluxes, energy and water vapor over a Caatinga ecosystem preserved in a dry year in Petrolina-PE

Objetivou-se com este trabalho analisar o comportamento sazonal dos fluxos de carbono, energia e água, e dos padrões diurnos das trocas gasosas de espécies ocorrentes em uma área de Caatinga preservada. O experimento foi conduzido na Embrapa Semiárido (9,05o S; 40,19o W; 350m), no município de Petrolina, PE, durante o ano de 2012, que foi caracterizado climaticamente pela ocorrência de longo período de estiagem, quando choveu apenas 92 mm. Os fluxos de carbono, energia e água foram medidos usando o sistema Covariância dos vórtices turbulentos acoplado a uma torre micrometeorológica de 16 metros. Ao longo do tempo foram feitas medições do conteúdo de água no solo e do nível de cobertura do solo (NCS), bem como campanhas para determinação da variação diurna das trocas gasosas (fotossíntese, transpiração e condutância estomática) de cinco espécies de maior ocorrência na área experimental (Poincianella microphylla (Mart. ex G. Don) L. P. Queiroz, Croton conduplicatus Kunth, Bauhinia cheilantha (Bong.) Steud., Manihot pseudoglaziovii (Pax & Hoffman), Commiphora leptophloeos (Mart.) Gillett). As campanhas foram realizadas em quatro datas, com diferentes disponibilidades hídricas, em intervalo de medições de 2 horas. A partir dos dados experimentais foi determinado o balanço de radiação e os fluxos de CO 2 (NEE), calor latente (LE), calor sensível (H) e de calor no solo, em escala sazonal e em dias específicos (a depender do NCS e das condições de nebulosidade), bem como as frações da radiação fotossinteticamente ativa absorvida e interceptada. A interação entre a atmosfera e a vegetação na troca de vapor d’água foi realizada por meio do fator de desacoplamento (Ω), da resistência da superfície e aerodinâmica. Os valores de LE foram integrados para a obtenção da evapotranspiração real diária. Os dados do NEE foi particionado por meio da aplicação de modelos matemáticos para a determinação da produtividade primária bruta e da respiração do ecossistema. Os resultados revelaram que a sazonalidade da disponibilidade de água durante o ano de 2012 influenciou o padrão dos balanços de radiação e de energia, maximizando a relação H/Rn (~ 77%) (em que, Rn é o saldo de radiação). Assim, a evapotranspiração sob condições de seca intensa foi dependente do déficit de pressão de vapor e do controle da superfície, demonstrando um forte acoplamento da vegetação com atmosfera (Ω ~ 0,04). Todavia, essa interação variou em resposta ao progresso da deficiência hídrica após os eventos de chuva, quando a eficiência de uso da água das espécies foi otimizada, mesmo com a intensa redução da assimilação de dióxido de carbono. As espécies P. microphylla, C. conduplicatus, B. cheilantha, e M. pseudoglaziovii apresentaram maior otimização do uso da água em função do horário do dia e das condições sazonais de disponibilidade hídrica. O ecossistema de Caatinga preservada atuou durante um ano climaticamente seco como uma fonte de carbono para a atmosfera, com uma emissão igual a 468,18 gC m -2 ano -1The objective of this study was to analyze the seasonal behavior of the carbon, energy and water fluxes, and the diurnal patterns of gas exchange of species occurring in an area of Caatinga preserved. The experiment was conducted at Embrapa Semi-Arid (9,05o S; 40,19o W; 350m), in the city of Petrolina, PE, during the year 2012, which was characterized by the occurrence of climatically long period of drought, when rained only 92 mm. Fluxes of carbon, energy and water were measured using the Covariância dos vórtices turbulentos system coupled with a micrometeorological tower of 16 meters. Over time measurements of water content in soil and the coverage index (CI) were made, as well as campaigns to determine the diurnal variation of gas exchange (photosynthesis, transpiration and stomatal conductance) of the five most common species in the experimental area (Poincianella microphylla (Mart. ex G. Don) LP Queiroz, Croton conduplicatus Kunth, Bauhinia cheilantha (Bong.) Steud., Manihot pseudoglaziovii (Pax & Hoffman), Commiphora leptophloeos (Mart.) Gillett). The campaigns were conducted in four different dates with different water availability in the range of measurements of two hours. From the experimental data we determined the radiation balance and CO 2 fluxes (NEE), latent heat (LE), sensible heat (H) and soil heat in seasonal scale and on specific days (depending on IC and of cloudy conditions), as well as the fractions of photosynthetically active radiation absorbed and intercepted. The interaction between the atmosphere and the vegetation in the exchange of water vapor was performed by means of the decoupling factor (Ω) of the surface resistance and aerodynamics. LE values were integrated to obtain the daily evapotranspiration. The data was partitioned NEE through the application of mathematical models for determination of the gross primary productivity and respiration of the ecosystem. The results revealed that the seasonality of water availability during the year 2012 influenced the pattern of the radiation balance and energy, maximizing H / Rn ratio (~ 77%) (where, Rn is the net radiation). Thus, evapotranspiration under conditions of severe drought was dependent on the vapor pressure and the surface control deficit, demonstrating a strong coupling of the vegetation with the atmosphere (~ 0.04 Ω). However, this interaction varied in response to the progress of water stress after rain events, when the efficiency of water use species was optimized, even with the intense reduction of the assimilation of carbon dioxide. The species P. microphylla, C. conduplicatus, cheilantha B. and M. pseudoglaziovii showed greater optimization of water use as a function of time of day and seasonal water availability conditions. The Caatinga ecosystem preserved acted during a climatically dry year as a source of carbon to the atmosphere, with an emission equal to 468.18 gC m -2 year -1 .Coordenação de Aperfeiçoamento de Pessoal de Nível Superio