Aplicações científicas das equações diferenciais

16

Manejo nutricional de plantas matrizes de Coffea canephora destinadas à produção de estacas.

Na propagação vegetativa de cafeeiros Coffea canephora são utilizados propágulos vegetativos, denominados estacas, que são provenientes de jardins clonais. Dessa forma, o manejo nutricional deste jardim deve ser planejado para que as plantas produzam o maior número de estacas possível e que estas estacas estejam nutricionalmente equilibradas. Assim, o objetivo nesta proposta foi avaliar o efeito de doses crescentes de fertilizantes nitrogenados em plantas matrizes de C. canephora sobre a produção de propágulos vegetativos e sobre o crescimento de mudas clonais. Para isso, o estudo foi dividido em duas etapas: na primeira, foram utilizados cafeeiros C. canephora variedade botânica Robusta, conduzidas em jardim clonal pertencente ao Programa de Melhoramento Genético da Embrapa-RO, onde as parcelas foram compostas por sete doses de nitrogênio (0; 50; 100; 150; 200; 250 e 300 kg nitrogênio por hectare por ciclo, aplicado na forma de ureia), divididas em quatro aplicações, durante 150 dias. Nesta fase, a produção de estacas foi avaliada em duas épocas, janeiro e junho de 2019. Já na segunda etapa, que teve como objetivo avaliar o crescimento das mudas, foi mensurado a massa das estacas, conteúdo nutricional das estacas e a produção de mudas, por meio de análise de crescimento, ao zero; 48; 61; 80; 101; 122; 143 e 164 dias após o estaqueamento - DAE, e análise das características vegetativas, aos 122 DAE. Concluise que no período de setembro a janeiro, os cafeeiros C. canephora produzem maior quantidade de massa vegetativa e, consequentemente, de propágulos vegetativos, que no período de janeiro a junho, nas condições da Amazônia Sul Ocidental. As concentrações de nutrientes nos tecidos variam com a época do ano em razão de disponibilidade de nutrientes no solo e com a quantidade de massa seca acumulada. Aumento das doses de nitrogênio resulta em incremento de massa vegetativa, de propágulos e das concentrações de nitrogênio e potássio, mas não afetam os teores de fósforo, cálcio, magnésio e enxofre nos propágulos vegetativos de C. canephora e, independentemente da dose de N aplicada, os teores de nutrientes nas estacas segue a ordem K>N>Ca>P>Mg>S. O conteúdo de N, K na estaca aumenta enquanto o conteúdo de Ca diminui e os teores de P, Mg e S não são alterados com o incremento de doses de nitrogênio, aplicados na forma de ureia, em plantas matrizes de cafeeiros C. Canephora. Estacas crescidas com maiores doses de N dão origem a mudas com maior comprimento e diâmetro de caule, volume de raízes, área foliar e massa seca da parte aérea e total. The vegetative propagation of Coffea canephora coffee plants uses vegetative propagules, called cuttings, which come from clonal gardens. In this way, the nutritional management of this garden might be planned so that the plants produce the largest number of cuttings possible and nutritionally balanced. The objective of this proposal was to evaluate the effect of nitrogen doses of fertilizers on C. canephora parent plants on the production of vegetative propagules and on the growth of clonal seedlings. The experiment was divided into two stages: in the first, C. canephora Robusta botanical variety coffee trees were used, performed on clonal garden of genetic improvement program of Embrapa-RO. the plots were composed of seven nitrogen doses (0 ; 50; 100; 150; 200; 250 and 300 kg nitrogen per hectare per cycle, applied as urea form), divided into four applications. The cuttings production was evaluated in two times, January and June 2019. In the second stage, the seedlings growth was measured from the parameters: the cuttings mass, the nutritional content of cuttings and the seedlings production, with analysis of growth, in days zero; 48; 60; 81; 102; 123; 140 and 160 after staking and analysis of vegetative characteristics, at 123 DAE. Between September and January, C. canephora coffee trees produce a greater amount of vegetative mass and, consequently, of vegetative propagules, than between January and June, under the conditions of the South Western Amazon. In the way, the nutrients concentrations in the tissues change with the time of the year due to the nutrients availability in the soil and with the amount of accumulated dry mass. Increased nitrogen doses result in an increase in vegetative mass, propagules and nitrogen and potassium concentrations, but do not affect the phosphorus, calcium, magnesium and sulfur levels in the vegetative propagules of C. canephora and, regardless of the N dose applied. The nutrient contents in the cuttings follows the order K> N> Ca> P> Mg> S. The N and K contents in the cutting increases while the content of Ca decreases and the P, Mg and S levels are not altered with the increase of nitrogen doses, applied in plants of coffee plants C. Canephora. The results indicated a significant relationship between higher N doses and production of seedlings with greater length and diameter of stem, volume of roots, leaf area and dry mass of the aerial part and total.Dissertação (Mestrado em em Ciências Ambientais) - Programa de Pós-Graduação em Ciências Ambientais, Universidade Federal de Rondônia, Rolim de Moura. Orientador: Marcelo Curitiba Espindula

Programa de remuneração variável : um estudo de caso na Empresa I. Riedi

Orientador: Joel Souza e SilvaMonografia (Especialização) - Universidade Federal do Paraná, Setor de Ciências Sociais Aplicadas, Curso de Especialização em Administração de Pessoa

Atividade biológica de solo sob cultivo múltiplo de maracujá, abacaxi, milho, mandioca e plantas de cobertura.

O objetivo deste trabalho foi avaliar o efeito de plantas de cobertura em cultivo consorciado de maracujá, abacaxi, mandioca e milho sobre a atividade biológica do solo em período chuvoso e de estiagem. O experimento foi conduzido em Rio Branco, Acre, em um ARGISSOLO AMARELO Alítico plíntico. O delineamento experimental utilizado foi o de blocos casualizados completos com parcelas subdivididas e quatro repetições. Nas parcelas foram estudadas épocas de avaliação (março, maio, agosto e outubro de 2011) e, nas subparcelas, plantas de cobertura [kudzu tropical (Pueraria phaseoloides), crotalaria (Crotalaria espectabilis), amendoim forrageiro (Arachis pintoi), feijão de porco (Canavalia ensiformis) e plantas espontâneas]. Foram avaliadas respiração (edáfica e basal), biomassa microbiana, e quocientes metabólico (qCO2) e microbiano (qMIC). No final do período chuvoso, em condições de adequada umidade e oxigenação do solo, a cobertura com crotalária potencializa a atividade microbiana juntamente com e feijão de porco, que proporciona maior respiração edáfica. No período com maior restrição do oxigênio no solo (outubro a março - estação chuvosa) e de água (agosto - característico da estação seca), o amendoim forrageiro mantém alta atividade microbiana. No período de maior precipitação pluviométrica (março), o solo sob plantas espontâneas apresenta maiores biomassa microbiana e eficiência metabólica

Precision production environments for sugarcane fields

Sugarcane (saccharum spp.) in Brazil is managed on the basis of “production environments”. These “production environments” are used for many purposes, such as variety allocation, application of fertilizers and definition of the planting and harvesting periods. A quality classification is essential to ensure high economic returns. However, the classification is carried out by few and, most of the time, non-representative soil samples, showing unreal local conditions of soil spatial variability and resulting in classifications that are imprecise. One of the important tools in the precision agriculture technological package is the apparent electrical conductivity (ECa) sensors that can quickly map soil spatial variability with high-resolution and at low-cost. The aim of the present work was to show that soil ECa maps are able to assist classification of the "production environments" in sugarcane fields and rapidly and accurately reflect the yield potential. Two sugarcane fields (35 and 100 ha) were mapped with an electromagnetic induction sensor to measure soil ECa and were sampled by a dense sampling grid. The results showed that the ECa technique was able to reflect mainly the spatial variability of the clay content, evidencing regions with different yield potentials, guiding soil sampling to soil classification that is both more secure and more accurate. Furthermore, ECa allowed for more precise classification, where new “production environments”, different from those previously defined by the traditional sampling methods, were revealed. Thus, sugarcane growers will be able to allocate suitable varieties and fertilize their agricultural fields in a coherent way with higher quality, guaranteeing greater sustainability and economic return on their production

Influence of nitrogen fertilization in mother plants on the growth and quality of clonal seedlings of Coffea canephora ?Robusta? plants.

The nutritional management of the coffee clonal garden influences the production and physiological quality and seedlings production of vegetative propagules. Thus, this study aimed to analyze the seedlings? production from clonal cuttings taken from Coffea canephora mother plants grown with increasing nitrogen mineral doses. The cuttings were taken from C. canephora var. botany Robusta, from the Embrapa Genetic Improvement Program of Rondônia. The mother plants received nitrogen fertilizer at different doses: 0 (Control); 50; 100; 150; 200; 250 and 300 kg of N per hectare divided into 4 applications, during 150 days of orthotropic stems growth (shoots). The following parameters were evaluated: Dry mass of cuttings, nutritional content of cuttings, and seedlings production, with growth analysis at 0, 48, 61, 80, 101, 122, 143, and 164 days after staking (DAS) and analysis of vegetative characteristics at 122 DAS. The nitrogen fertilization in the mother plant resulted in the variation of macronutrient accumulation in cuttings, but the order K> N> Ca> P> Mg> S was maintained, regardless of N dose. In addition, a positive correlation between nitrogen doses and dry matter accumulation, as well as the physiological quality of seedlings was identified

Navigating 'the pit of doom': Affective responses to teaching 'grammar'

publication-status: Publishedtypes: ArticleThis article presents the outcomes of a study investigating current secondary English teachers' beliefs about grammar teaching, and illustrates the salience of teachers' emotional response to the issue. Interviews with 31 teachers reveal two discourses which frame the ways in which teachers express their feelings: a dominant discourse of grammar as threatening, reactionary and dull, and an oppositional discourse which positions grammar as inspiring, fascinating, and empowering. The influence of these discourses on practice is explored, along with examples of how attitudes can change as a result of participation in a research project. © 2012 National Association for the Teaching of English

Paving the way for research findings: writers' rhetorical choices in education and applied linguistics

Notwithstanding the existence of previous investigations into how research results are presented in different academic disciplines, fewer studies have looked into how authors pave the way for their results, the interdisciplinary differences in ‘result pavements’, and the interconnections between their communicative functions and linguistic choices. Using the techniques of genre analysis, I have analyzed two corpora of research reports in applied linguistics and education in order to identify the possible ways in which experienced writers schematically pave the way for their findings. Using evidence based on authentic research articles, this study demonstrates how writers set the stage for their research results by (i) demonstrating their control of the structure and flow of result-related information, (ii) connecting past research with a current finding while furnishing pertinent background elements that lead the readership progressively to specific findings, (iii) regenerating readers’ interest in their initial research purposes, and (iv) deploying locatives to embed results in a ‘space-saving strategy’ aimed at presenting an abridged Results section. I have also analyzed interdisciplinary differences in the frequencies of these rhetorical steps and the range of intricate linguistic mechanisms employed by authors as communicative resources in each step to establish a smooth rhetorical transition that sets the stage for their research results