Bidens pilosa L. (Asteraceae) control in sunflower with residual herbicides

One of the most damaging species in sunflower crops in Brazil is the hairy beggartick (Bidens pilosa L). The large number of seeds, the various vegetative cycles during the year, the staggered germination and the scarcity of selective and effective herbicides to control this weed in sunflower are some of attributes that hinder the control of hairy beggartick populations. Two experiments were carried out to evaluate the control of hairy beggarticks, as well as sunflower tolerance to herbicides. The treatments were as follows: S-metolachlor (1,200 and 2,400 g ai ha-1), flumioxazin (60 and 120 g ai ha-1), and sulfentrazone (150 and 300 g ai ha-1) and two controls (weedy and weed-free check). The selectivity of the herbicides was higher at low doses. Flumioxazin and sulfentrazone caused injury to sunflowers at the highest doses and mainly in sandy soils. Although S-metolachlor did not cause visual symptoms of injury, the higher dose reduced sunflower yield. The herbicides sulfentrazone and flumioxazin provided satisfactory control of hairy beggartick plants in both types of soils. S-metolachlor presented medium control of hairy beggarticks in clay soil; however, its efficiency was slightly higher when applied in sandy soil. The most efficient herbicide for controlling hairy beggartick plants was flumioxazin, followed by sulfentrazone

Bidens pilosa L. (Asteraceae) control in sunflower with residual herbicides

One of the most damaging species in sunflower crops in Brazil is the hairy beggartick (Bidens pilosa L). The large number of seeds, the various vegetative cycles during the year, the staggered germination and the scarcity of selective and effective herbicides to control this weed in sunflower are some of attributes that hinder the control of hairy beggartick populations. Two experiments were carried out to evaluate the control of hairy beggarticks, as well as sunflower tolerance to herbicides. The treatments were as follows: S-metolachlor (1,200 and 2,400 g ai ha-1), flumioxazin (60 and 120 g ai ha-1), and sulfentrazone (150 and 300 g ai ha-1) and two controls (weedy and weed-free check). The selectivity of the herbicides was higher at low doses. Flumioxazin and sulfentrazone caused injury to sunflowers at the highest doses and mainly in sandy soils. Although S-metolachlor did not cause visual symptoms of injury, the higher dose reduced sunflower yield. The herbicides sulfentrazone and flumioxazin provided satisfactory control of hairy beggartick plants in both types of soils. S-metolachlor presented medium control of hairy beggarticks in clay soil; however, its efficiency was slightly higher when applied in sandy soil. The most efficient herbicide for controlling hairy beggartick plants was flumioxazin, followed by sulfentrazone.One of the most damaging species in sunflower crops in Brazil is the hairy beggartick (Bidens pilosa L). The large number of seeds, the various vegetative cycles during the year, the staggered germination and the scarcity of selective and effective herbicides to control this weed in sunflower are some of attributes that hinder the control of hairy beggartick populations. Two experiments were carried out to evaluate the control of hairy beggarticks, as well as sunflower tolerance to herbicides. The treatments were as follows: S-metolachlor (1,200 and 2,400 g ai ha-1), flumioxazin (60 and 120 g ai ha-1), and sulfentrazone (150 and 300 g ai ha-1) and two controls (weedy and weed-free check). The selectivity of the herbicides was higher at low doses. Flumioxazin and sulfentrazone caused injury to sunflowers at the highest doses and mainly in sandy soils. Although S-metolachlor did not cause visual symptoms of injury, the higher dose reduced sunflower yield. The herbicides sulfentrazone and flumioxazin provided satisfactory control of hairy beggartick plants in both types of soils. S-metolachlor presented medium control of hairy beggarticks in clay soil; however, its efficiency was slightly higher when applied in sandy soil. The most efficient herbicide for controlling hairy beggartick plants was flumioxazin, followed by sulfentrazone

The cellular epitranscriptome

Several chemical modifications in cellular RNAs have been identified to date. The most common internal modification of eukaryotic RNAs is known as m6A. This modification is able to configure the outcome of gene expression by adjusting RNA decay, translation efficiency, RNA structure and alternative splicing. Although thousands of m6A sites were found in RNAs of several plant species, nearly nothing is known about the impact of m6A on plant acclimation. Here, we showed that mRNAs encoding writers, erasers and readers - proteins capable of installing, removing and recognizing/interpreting RNA modifications, respectively, - are responsive to cold, heat and high light conditions in Arabidopsis thaliana. Quantification of m6A by mass spectrometric analysis showed that m6A-modified poly(A)-enriched mRNAs are more abundant under cold acclimation. Under this condition, knockdown lines for components of the major m6A writer complex showed a decrease in photosynthetic performance, especially in the fip37-4 mutant. Immunological analysis of photosynthetic proteins and blue native gels has shown that under cold specific proteins and supercomplexes are downregulated in fip37-4. Interestingly, fip37-4 has a further role in thylakoid organization under cold as revealed by chloroplast ultrastructure analysis. In addition, ROS formation was increased while the expression of cold acclimation-related genes was reduced in fip37-4 at low temperatures. Plant development regarding leaf area, weight, chlorophyll/anthocyanin content and root development was impaired under control, but a much stronger deficiency especially in photosynthesis was clear under cold acclimation. Altogether, these results indicate that FIP37-based RNA methylations play crucial roles in plastid functions under cold and several other aspects of plant development

Underwater Communications based on Resonant Inductive Links

Em anos mais recentes, os veículos não tripulados têm sofrido um avanço considerável no seu desenvolvimento. Devido ao subsequente aumento de interesse na exploração do oceano, em especial zonas de condições extremas cujo acesso está impossibilitado. Em concreto, nas aplicações subaquáticas, existem problemas substanciais relativos ao carregamento de forma wireless dos aparelhos, mais especificamente, à monitorização deste processo, assim como, na transferência dos dados recolhidos. Esta dissertação apresenta uma solução para o controlo de parâmetros associados ao carregamento wireless, reaproveitando o acoplamento indutivo ressonante para, além da transferência de potência já implementada, transmitir dados. Denote-se que o estudo e implementação foram desenvolvidos num sistema com um comutador de alta tensão, optimizado para uma resistência de carga igual a 12.5 Ohm, uma frequência de ressonância de 240 kHz para uma transferência de potência na ordem dos 80 W com uma eficiência máxima no acoplamento de 94%. O trabalho desenvolvido explora um patamar substancial de corrente disponível, desde 0.5 A a 2.5 A com um conjunto de resistências entre 1 Ohm a 11 Ohm. Com estes valores é possível determinar diferentes estados que, por sua vez, permitem uma comunicação wireless com um grande alcance dinâmico. A eficiência geral do acoplamento não sofre uma grande alteração para os diferentes estados necessários para o envio de informação. Sabendo que o teor de sal afeta diretamente o acoplamento e, consequentemente, os níveis de corrente do sistema, e ainda que os valores de salinidade do mar variam de região para região, é possível regular esta variação mudando o valor da resistência responsável pela modulação da carga, reforçando a modularidade do sistema. Este desenvolvimento apresenta uma solução simples e viável, apresentando-se como uma forte alternativa ao uso de circuitos externos adicionais.During more recent years there has been a considerable advancement in unmanned vehicles, more so in autonomous underwater vehicles, following the increasing interest in exploring unreachable parts of the ocean. Underwater autonomous work poses substantial obstacles when it comes to wirelessly charging the devices and most importantly to the monitoring of such operation, as well as the transfer of the data gathered. This thesis presents a solution for overseeing the parameters that come with the wireless charging of a system, repurposing the resonant inductive link to transmit bits of data in addition to the power transfer already in place. Furthermore, the work was developed on system designed with a high-voltage switching power driver, optimized for load resistance equal to 12.5 Ohm, having a resonance frequency of 240 kHz for a power transfer in the order of 80 W with a link efficiency up to 94%. The present work explores the substantial threshold of current available at the primary coil, from 0.5 A to 2.5 A with a variation of resistance from 1 Ohm to 11 Ohm seen at the secondary coil. This allows for a detection of different states which provide a wireless communication with a wide dynamic range. The overall efficiency of the link is not greatly affected by the different states necessary to transmit information. Knowing that the salinity value of the sea differs from region to region and in turn, both the levels of current and threshold are affected, it is possible to regulate the value of the resistance responsible for the load modulation to atone such difference, which makes for a system with a high level of modularity. This presents a simple and viable solution that is a clear alternative to the need of additional aftermarket circuits to monitor and assist the charging of devices underwater

Custos ecológicos : dilemas dacotonicultura em Mato Grosso

Este trabalho discute os dilemas ecológicos do capital aplicado na cotonicultura no estado de Mato Grosso, no Centro-Oeste do Brasil. O modelo tecnológico utilizado é o chamado de "revolução verde", que se inicia com corte raso da mata nativa e depois estabelece culturas dependentes de insumos químicos, que geram erosão, perda de nutrientes do solo e perda de funções ecossistêmicas. A perda da fertilidade natural força o uso cada vez maior de agrotóxicos e fertilizantes. A estagnação da produtividade da terra conjugada com a elevação dos custos do trabalho mecânico e dos insumos aumenta o custo de produção de algodão, gerando dúvidas sobre a capacidade de competição do ramo. É desta forma que se expressam os custos ecológicos na monocultura do algodão no trópico úmido. Este modelo tecnológico não apresenta sinais de evolução rumo a uma nova racionalidade produtiva agroecológica necessária para recuperar a estrutura e a funcionalidade dos ecossistemas naturais locais e a revitalizar os sistemas de cotonicultura da região.This paper discusses the ecological dilemmas of agrarian capital applied in cotton crops in MatoGrosso. The technological model used has generated strong homogenization of the environment, loss of nutrients in the soil and caused ecological imbalance that has pressed the application of capital in the form of pesticides and fertilizers. The stagnation in productivity of land coupled with the rising costs of pest control has raised the price of cotton, creating doubts about the competition ability of this cluster. The ecological costs involved in the cotton monoculture in the humid tropic can make unviable the present model. This model doesn't show signal of evolution to a new productive rationality capable to sustain the structure and function of ecosystems that support the techno-economic projects

Consumo de combustíveis no Brasil e Mato Grosso: estimativa do custo ecológico da emissão de gases de efeito estufa

<div align="justify">O principal objetivo deste trabalho foi estimar o nível da emissão de gases deefeito estufa (GEE) a partir do consumo de combustíveis fósseis e renováveis noBrasil e no estado de Mato Grosso entre os anos de 2003 e 2010. Uma vezreconhecido o quantum de emissão de GEE, calculou-se o custo ecológico destaemissão a partir dos preços da tonelada de carbono comercializada na BolsaEuropeia do Clima e na Bolsa do Clima de Chicago. A partir deste exercício,estimou-se o peso deste custo ecológico sobre o Produto Interno Bruto do Brasil ede Mato Grosso no período analisado, considerando hipoteticamente a incorporaçãodestes custos externos na matriz produtiva de ambas as referências espaciais.Utilizando a base de dados de consumo de combustíveis do Brasil e de Mato Grossoda Agência Nacional de Petróleo, Gás Natural e Biocombustíveis, foi empregado oMétodo “Top-Down” ou método de referência do IPCC para estimar as emissões dedióxido de carbono. Atrelou-se o preço do carbono nas Bolsas da Europa e dosEstados Unidos à emissão de gases do efeito estufa, para se estimar os custosexternos, chamados aqui também de custos ecológicos. Os resultados mostram queos custos ecológicos estão tendendo a redução neste período, tanto pela contençãoda emissão de GEE frente ao PIB quanto pela tendência negativa dos preços docarbono nas bolsas internacionais.<br><br>Abstract The main objective of this study was to estimate the level of greenhouse gasesemission (GHG) from the consumption of fossil and renewable fuels in Brazil and inthe state of Mato Grosso between the years 2003 and 2010. Once recognized thequantum of GHG emission, was calculated the ecological cost of this emission asfrom the prices of the ton of carbon traded on the European Climate Exchange andon the Chicago Climate Exchange. From this exercise, was estimated the weight ofthis ecological cost on Gross Domestic Product (GDP) of the Brazil and of MatoGrosso in the period analyzed, considering hypothetically the incorporation of theseexternal costs in the productive matrix of both the spatial references. Using thedatabase of fuel consumption in Brazil and Mato Grosso of the National Agency ofPetroleum, Natural Gas and Biofuels, we employed the method "Top Down" orIPCC’s reference method to estimate emissions of carbon dioxide. Attached the priceof the carbon in the exchanges of the Europe and of the United States to greenhousegases emission, to estimate the external costs, called here of the ecological costs.The results show that ecological costs are tending at reduction during this period,both by contention of the GHG emission compared to GDP as by the negative trendof the carbon prices in the international exchanges.</div

TAMANHO AMOSTRAL PARA CONSERVAÇÃO EX SITU DE ESPÉCIES ARBÓREAS COM SISTEMA MISTO DE REPRODUÇÃO

O objetivo deste trabalho foi determinar o número de plantas por progênie e o número de progênies necessárias para a conservação ex situ de populações de espécies arbóreas, com sistema misto de reprodução. O número de progênies foi determinado da relação entre o tamanho efetivo alvo da conservação ( N.) e o tamanho efetivo de variância ( N ) de uma simples progênie de polinização • 0,8)

Sunflower resistance to acetolactate synthase-inhibiting herbicides

Sunflower is very sensitive to herbicides applied in post-emergence to control broad-leaf weeds. Researchers have developed herbicide-resistant genotypes to imidazolinone herbicides. This study aimed to evaluate the selectivity of imidazolinone and sulfonylurea herbicides applied on sunflower plants (Tera 8003 and Tera 8011) resistant to acetolactate synthase-inhibiting herbicides. The experiments were conducted at Embrapa Gado de Leite, in Coronel Pacheco, Minas Gerais State, and Valença, Rio de Janeiro State, Brazil. The experimental design was randomized complete blocks, with four replications. The treatments consisted of hoed control, imazapyr 25 g a.i. ha-1 and 50 g a.i. ha-1, imazethapyr 70 g a.i. ha-1 and 100 g a.i. ha-1, nicosulfuron 20 g a.i. ha-1 and 32 g a.i. ha-1, and chlorimuron 7.5 g a.i. ha-1 + 0.05% v/v of mineral oil. The crop injury percentage, chlorophyll content (SPAD index), plant height, dry matter production and percentage, and yield were evaluated. The imazethapyr doses (70 g a.i. ha-1 and 100 g a.i. ha-1) were the most selective ones, the nicosulfuron dose (20 g a.i. ha-1) showed moderate tolerance, and imazapyr and chlorimuron caused greater injury, for both sunflower hybrids

Control of volunteer soybean plants in sunflower crop

Sunflower (Helianthus annuus) sown offseason, after soybean crop (Glycine max), is affected by the competition imposed by volunteer plants. Two experiments were carried out to evaluate the control of volunteer soybean plants in sunflower crops. The sulfentrazone herbicide (75 g ha-1, 100 g ha-1 and 250 g ha-1) causes phytotoxicity to sunflower immediately after application, however, plants recover, with no yield losses. These doses do not cause the total death of volunteer soybean plants, but temporarily paralyzes their growth, avoiding the competition with the sunflower crop. The glufosinate ammonium and ametryn herbicides are effective in controlling volunteer soybean plants, however, symptoms of phytotoxicity in the sunflower crop are high, reflecting in losses of dry weight biomass and crop yield. The other treatments do not provide satisfactory control of volunteer soybean plants and even reduce the sunflower dry weight biomass and yield