Available radiant energy in an agroforestry system with rubber tress: the productivity of common beans

O feijoeiro (Phaseolus vulgaris L.) adapta-se bem à radiação difusa, possibilitando seu cultivo em sistemas consorciados. O sistema agroflorestal (SAF) de seringueira (Hevea spp.) e feijoeiro é relatado em diversos países tropicais, com diversas vantagens em termos de produtividade e retorno econômico. Porém, os processos fisiológicos envolvidos na interação entre as duas espécies não estão devidamente compreendidos. Neste estudo, visou-se compreender os efeitos da modificação do ambiente pelas árvores na produtividade do feijoeiro, cultivado em SAF, em função de sua distância. Observo-se que a produtividade do feijoeiro está direta e positivamente relacionada à irradiância disponível, sendo diminuída com a proximidade das árvores. Assim, a mensuração ou estimativa da irradiância pode ser utilizada na predição do desempenho da leguminosa em SAF. O SAF proposto é adequado, visto que o excesso de radiação à cultura intercalar é atenuado pelas seringueiras durante o outono; no inverno, quando não ocorre este excesso, as seringueiras atenuaram menor porcentagem devido à queda de suas folhas. Não foram observadas diferenças no índice de colheita devido ao sombreamento; este, porém foi de 0,54 na semeadura de outono e de 0,38 na de inverno, parecendo ser característico para a cultura e a época de colheita.It is observed a great adaptation of common beans (Phaseolus vulgaris L.) to diffuse light, making possible its cultivation in association with other crops. Agroforestry systems (AFS) of rubber trees (Hevea spp.) and beans are extensively reported in many tropical countries, with many advantages in productivity and economic revenue terms. However, the physiological processes involved in the interaction between these species are not well understood yet. This study was aimed to verify the effects of environment modification due to trees in the productivity of common beans grown in AFS as a function of their distance across the rubber tree planting line. It was observed that beans productivity is direct and positively related to irradiation availability, decreasing with the proximity of the trees. Thus irradiation measurement or simulation can be useful on predicting beans production in AFS. The proposed AFS is suitable, as radiation excess to the intercrop is attenuated by the rubber tress during the autumn; in winter, when this excess does not occur, rubber trees attenuated a smaller percentage due to their leaffall. It was not observed differences in harvest index due to shade; however these were 0.54 in autumn and 0.38 in winter seeming to be characteristic to the crop and harvest time.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

A floresta aberta com bambu no sudoeste da Amazônia : padrões e processos em múltiplas escalas

Tese (doutorado)—Universidade de Brasília, Instituto de Ciências Biológicas, Programa de Pós-Graduação em Ecologia, 2001.Florestas ombrófilas abertas com bambus arborescentes e espinhosos do gênero Guadua, cobrem cerca de 180.000 km2 ' do sudoeste da Amazônia e são facilmente identificadas através de imagens do satélite Landsat. Além de semelparas e monocárpicas, estas espécies de bambu possuem incrível habilidade de crescimento horizontal através de rizomas, crescimento vertical extremamente rápido e hábito semiescandente. Guadua weberbaueri tem um ciclo de vida que varia de 29 à 32 anos e distribuição ampla na região. A amplitude de distribuição e o caráter dominante desses bambus determinam padrões estruturais tanto das comunidades ecológicas quanto da paisagem. Estes padrões são a resultante de mecanismos e processos que ocorrem nas escalas populacional e organísmica (individual). Este estudo objetivou: i) identificar as relações entre as diferentes escalas ecológicas na determinação dos padrões e dos processos que expliquem a distribuição das florestas com bambu no Estado do Acre; ii) na escala individual, investigar a estrutura dos rizomas, a estratégia de crescimento clonal e a alocação de biomassa de Guadua weberbaueri; iii) na escala populacional, calcular as taxas de crescimento, recrutamento e mortalidade de colmos de G. weberbaueri; iv) na escala de comunidade, analisar os efeitos de G. weberbaueri sobre a estrutura e a dinâmica da floresta; v) na escala de paisagem, identificar os padrões temporais e espaciais da floresta com bambu; v) desenvolver um modelo ecológico conceituai que integre as informações geradas nas diferentes escalas. Na escala individual, há evidências de integração fisiológica entre os módulos, e a forma de crescimento clonal, combina as estratégias guerrilheira e lalangeal; estes são os mecanismos de compartilhamento de recursos, de forageamento e captura de espaço, que afetam a capacidade competitiva de G. weberbaueri. O crescimento dos colmos sofre forte influência da sazonal idade, especialmente durante a estação chuvosa. O incremento médio na altura total foi 3,4 m/mês. A média da taxa de recrutamento e de mortalidade de colmos para o período de 1996-2000, foi de 21% e 14%, respectivamente. É provável que as variações climáticas observadas no período tenham sido promovidas pelos fenômenos El Nino e La Nina. Guadua weberbaueri afeta a estrutura da comunidade florestal, reduzindo a densidade de árvores e a área basal da floresta, e diminuindo de 30 à 50% o potencial de armazenamento de carbono. O bambu também altera a composição florística, reduzindo em quase 40% o número de espécies em uma amostra de um hectare. A riqueza resultante é uma das menores da Amazônia. A ação seletiva do bambu favorece o crescimento de espécies características dos estágios iniciais da sucessão ecológica, cujo ciclo de vida curto em implicações diretas sobre a dinâmica da floresta. A taxa de mortalidade anual (3,4%) e o turnover (29 anos), permitem caracterizar essa floresta como uma das mais dinâmicas da Amazônia. Na escala de paisagem, bordas nítidas foram observadas entre a floresta com bambu ocorrendo em terreno colinoso e solo argiloso da Depressão Rio Acre-Javari e a floresta sem bambu no terreno dissecado e solo arenoso no Planalto Rebaixado da Amazônia Ocidental, onde o bambu inexiste. Bordas arredondadas identificadas entre a floresta com bambu e a floresta sem bambu sugerem que a expansão ou está em curso ou que foi mediada por fogo pretérito. Internamente a floresta com bambu apresenta dois tipos de borda. Bordas temporais nítidas, que ocorrem quando distintas populações de Guadua apresentam assincronia no florescimento e mortalidade, e bordas difusas, foram relacionadas com a variação na densidade do bambu ao longo da topossequência (mais densos nas vertentes e fundos de vale). As relações entre os padrões e processos estudados foram exploradas a partir da integração do conhecimento ecológico nas múltiplas escalas, através do desenvolvimento de um modelo ecológico descritivo. Este modelo explora como os mecanismos biológicos que ocorrem em escalas mais finas, podem assinalar padrões detectados em grande escala.Open forests with arborescent and thorny bamboos of the genus Guadua, covers about 180,000 km2 of the Southwestern Amazonia and are easily identified through Landsat satellite images. Guadua species are semelparous and monocarpic, grow horizontally through rhizomes, and have a fast growth and climbing habit. Guadua weberbaueri has a 29-32-year life-cycle and has a widespread distribution in the region. Bamboo distribution and dominance are determinants of both community and landscape patterns. These patterns are the result of mechanisms and processes that occur at the population and organismic (individual) scales. The aim of this study was: i) to identify the relationships between patterns and processes that explain the bamboo-forest distribution in Acre State; ii) at the individual scale, to investigate the structure of rhizomes, the clonal growth strategy, and biomass alocation in Guadua weberbaueri', iii) at the population scale, to record growth, recruitment and mortality of G. weberbaueri culms; iv) at the community scale, to analyze the effects of G. weberbaueri on the structure and dynamics of the forest; v) at the landscape scale, to identify spatial and temporal modifications in bamboo-forest; vi) finally to develop a conceptual ecological model that integrates information generated in the diferent scales. At the individual scale, there arc evidence of physiological integration between ramcis; clonal growth form combines both guerrilla and phalanx strategies; these are the mechanisms G. weberbaueri uses for foraging for resources for spatial occupation; both affect the competitive ability of the species. Culm growth is affected by climate seasonality, particularly during the rainy season. The average increment in height was 3.4 meters per month. The rate of culm recruitment and mortality during the 1996-2000 period, was 21% and 14%, respectively. Possibly the observed variation was promoted by the Eil Nino and La Nina phenomena. Giuidua weberbaueri affects community structure, reducing tree density and the basal area of the forest, and by decreasing the carbon storage potencial by 30-50%. The bamboo alters the floristic composition, reducing the number of species in a one hectare plot by almost 40%. The resulting richness is one of the smallest reported for the Amazon. The bamboo also favors the growth of early successional trees, whose short life cycle may have direct effects on the forest dynamics. The annual tree mortality rate (3.4%) and turnover time (29 years), make this as one of the most dynamic forests in the Amazon. At the landscape scale, quite distinctive borders were observed between forest with bamboos occuring in slope terrains and loamy soil of the Rio Acre-Javari depression; on the other hand the forest without bamboos occur in the dissected land and sandy soils of the Planalto Rcbaixado da Amazonia Ocidental. Round borders identified in the images suggest either ongoing expansion or expansion that was mediated by fire. Inside the forest with bamboo two border types are identified: a distinctively “temporal border” that occurs when different Guadua‘s populations present asynchronous mass flowering and mortality; and diffuse borders, which is related to differences in bamboo density along the catena (denser in the slopes and valleys). The relationship between the observed patterns and mechanisms (processes) studied were explored in a conceptual model that integrates the multiple ecological scales. The model explores how the biological mechanisms at finer scales can affect patterns detected at broader scales

Making and making use of a baseline: botanical research and the legacy of Chico Mendes

The vision and charisma of Chico Mendes made Acre a destination for many people fascinated and inspired by the great socio-environmental experiments he was proposing; his murder only increased that interest.  The extractivist movement engendered by Chico Mendes, with a potentially strong role for basic research, was the primary reason that The New York Botanical Garden (NYBG) committed scientists and resources in order to study the flora of Acre and Southwestern (SW) Amazonia.  At the outset of our  collaborative agreement with the Universidade Federal do Acre (UFAC)[Federal University of Acre], Acre was botanically one of the least-known parts of Amazonia.  Thirty years later, it has come to be one of the best-known parts, due in great part to the First Catalogue of the Flora of Acre, Brazil, which contributed with the first ten percent of the checklist to the flora of all Brazil.  More importantly, we were able to add original data to arguments for the making of new protected areas in Acre.  In these process, we established Acre as a point of reference for botanical knowledge about Southwestern Amazonia. The NYBG/UFAC partnership was an early participant in the MAP (Madre de Dios-Acre-Pando) consortium and helped designate priorities portions of SW Amazonia to conservation.  Our botanical research in this region has emphasized potential applications to resource management.  Most recently, our efforts have focused on reforming forest management and monitoring by continuing to build on our baseline of knowledge of the flora, proposing better protocols for sampling and collection in forest inventories, offering training  courses to the certification of new generations of “master woodsmen”, and developing tools and resources for tree identification.  Our capacity-building efforts now focus primarily on communities situated in or close by protected areas, treating them as participants and collaborators in forest inventory and monitoring.  Making good use of traditional knowledge and focusing on forest communities as full participants and partners in projects devoted to inventory, management, monitoring and conservation of forests throughout Amazonia, we are doing our small part to honor the legacy of Chico Mendes

Contribuçao para o conhecimiento da flora vascular da serra do Açor (Portugal)

SILVEIRA, P. C., PAIvA, 1. A. R. & MARcos SAMANIEGO, N. 1998. Contribution to the knowledge of the vascular flora of Serrado A~or (Portugal). flor Complutensis 22: 145-151. Fifteen taxa with chorological interest are reponed from Sena do A 9or, situated between ihe provinces Beira Alta, Bejín Litoral anó Bejín Baixa in Portugal. The most interesting records include Ervsimum lagascae Rivas Goday & Bellot, Festuca summilusitana Franco & Rocha Afonso, Saxífraga fragosol Sennen and Fryngium duriar Gay ex Boiss.SILVEtRA, P. C., PAIVA, J. A. R. & MARCOS SAMANIEGO, N. 1998. Contribución al conocimiento de la flora vascular de la Sena do A~or (Portugal). flor Complutensis 22: 145-15 1. Se comentan 15 táxones deinterés corológico para la Sena do A~or, situada entre las provincias Beira Alta, Beira Litoral y Beira Baixa en Portugal. Destacamos Erysimum lagascae Rivas Goday & Bellot, Festuca summilusitana Franco & Rocha Afonso, Saxífraga fragosoi Sennen y Eryngium duriae Gay ex Boiss

Innovative Theoretical Approaches Used for RF Power Amplifiers in Modern HDTV Systems

The essential purpose of this chapter is to introduce theoretical and numerical approaches that can be used for modeling nonlinear effects that appear intrinsically in the design of power amplifiers that have been used widely in many modern high-density television (HDTV) architectures. Important effects like the pre-distortion using adaptive techniques, with distinct characteristics like amplitude, phase, and frequency, as well as, their specific nature such as AM/AM, AM/PM, PM/AM, and PM/PM, and constitute one of the main directions of this research. All theoretical and technological approaches have been supported by a consistent set of numerical data performed with one of the most important platform of simulations used in the great area of Radio Frequency (RF) and Microwave structures. As a direct application, we are introducing some efficient processes that can be used for the characterization of RF systems with a set of consistent laboratorial measures that permit us to visualize the effective cost and a complete architecture for the characterization of high-power amplifiers. With the continuous and innovative technological demand that is imposed by the international marketing has a great importance to find versatile systems that are capable of measuring several amplifier characteristics, as gain, output power, inter-modulation distortion of different signals, efficiency, current, and temperature that constitute another direction of research that has been demanded strongly for news advanced technologies used widely in modern HDTV systems

Physiological responses of Amazonian flooded plants to the global climate change

Conforme previsões do último relatório do IPCC (Intergovernmental Panel of Climatic Change) em 2007, até meados deste século haverá um aumento na concentração de CO2 na atmosfera podendo chegar a 720 μmol mol-1. Consequentemente haverá uma elevação da temperatura de até +3 °C, o que ocorrerá em conjunto com mudanças no padrão de precipitação. O mesmo relatório sugere que isto poderá acarretar uma substituição gradual da floresta tropical por vegetação similar a uma savana na parte oriental da Amazônia, porém nada é conclusivo. Diante dessas possibilidades, pergunta-se - Como as espécies de árvores que compõem as regiões de alagamento da Amazônia irão responder às alterações climáticas por vir? Apesar dessas previsões serem pessimistas, o alagamento ainda ocorrerá por vários anos na Amazônia e é de grande importância compreender os efeitos do alagamento sobre as respostas fisiológicas das plantas num contexto das mudanças climáticas. Os principais efeitos sobre a sinalização metabólica e hormonal durante o alagamento são revisados e os possíveis efeitos que as mudanças climáticas poderão ter sobre as plantas amazônicas são discutidos. As informações existentes sugerem que sob alagamento, as plantas tendem a mobilizar reservas para suprir a demanda de carbono necessário para a manutenção do metabolismo sob o estresse da falta de oxigênio. Até certo limite, com o aumento da concentração de CO2, as plantas tendem a fazer mais fotossíntese e a produzir mais biomassa, que poderão aumentar ainda mais com um acréscimo de temperatura de até 3 °C. Alternativamente, com o alagamento, há uma diminuição geral do potencial de crescimento e é possível que quando em condições de CO2 e temperatura elevados os efeitos positivo e negativo se somem. Com isso, as respostas fisiológicas poderão ser amenizadas ou, ainda, promover maior crescimento para a maioria das espécies de regiões alagáveis até o meio do século. Porém, quando a temperatura e o CO2 atingirem valores acima dos ótimos para a maioria das plantas, estas possivelmente diminuirão a atividade fisiológica.According to the last report of IPCC (Intergovernmental Panel of Climatic Change, 2007) an increase in atmospheric CO2 concentration to ca. 0.072% is predicted to occur until the middle of this century. As a result, a tandem elevation of temperature of ca. +3 °C and a decrease in precipitation are to be expected. It has also been suggested that this scenario may lead to a gradual substitution of the tropical forest for savanna-like vegetation in Eastern parts of the Amazon. Within this perspective, a worth question is how the tree species that make up the Amazonian floodplains will respond to the global climatic change? Although predictions have been quite pessimistic, flooding of part of the Amazon will continue to occur for several years and it is important to understand its synergistic effects within the scenario of climate change. In this work, features related to plant metabolism and hormonal signaling during flooding is revised, and the possible effects that the climatic changes might have on plants from the Amazon are discussed. The information available in the literature suggests that under flooding, plants tend to mobilize storage compounds to supply carbon demand needed for maintenance metabolism under the effect of stress caused by the lack of oxygen. In contrast, under elevated CO2 concentration, plants tend to increase photosynthesis and biomass. With an increase of about 3 °C these parameters may increase even more. Alternatively, with flooding, there is a general decrease in growth potential and it is possible that while favorable conditions of elevated CO2 and temperature prevail, the positive effects may be counterbalanced by the negative effects of flooding. Thus, the physiological responses might be imperceptible or promote further growth up to the middle of the 21st Century for most species that occur in the floodplains. However, if temperature and CO2 levels surpass the threshold of optimal conditions for most plants, a decrease in physiological activity is to be expected

Early Identification of Abused Domains in TLD through Passive DNS Applying Machine Learning Techniques

DNS is vital for the proper functioning of the Internet. However, users use this structure for domain registration and abuse. These domains are used as tools for these users to carry out the most varied attacks. Thus, early detection of abused domains prevents more people from falling into scams. In this work, an approach for identifying abused domains was developed using passive DNS collected from an authoritative DNS server TLD along with the data enriched through geolocation, thus enabling a global view of the domains. Therefore, the system monitors the domain’s first seven days of life after its first DNS query, in which two behavior checks are performed, the first with three days and the second with seven days. The generated models apply the machine learning algorithm LightGBM, and because of the unbalanced data, the combination of Cluster Centroids and K-Means SMOTE techniques were used. As a result, it obtained an average AUC of 0.9673 for the three-day model and an average AUC of 0.9674 for the seven-day model. Finally, the validation of three and seven days in a test environment reached a TPR of 0.8656 and 0.8682, respectively. It was noted that the system has a satisfactory performance for the early identification of abused domains and the importance of a TLD to identify these domains