Duplication of the chromosome number of diploid Brachiaria brizantha plants using colchicine.

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Gain-Scheduled Controller for Fault Accommodation in Linear Parameter Varying Systems with Imprecise Measurements

We present the design of H∞ and H2 gain-scheduled fault-accommodation controllers for discrete-time Linear Parameter Varying systems. We design our conditions as Bilinear Matrix Inequalities, assuming that the scheduled parameters are imprecise, which is a commonly found characteristic of practical applications that happens due to measurement noise and inaccuracy on its estimation/acquisition procedure. The proposed solution is based on the use of a multi-simplex approach for solving the main conditions, which guarantees the stability of the system under imprecise measurements on the scheduling parameters. The efficacy of the proposed approach is illustrated with a numerical example

On-Chip Tests for the Characterization of the Mechanical Strength of Polysilicon †

Microelectromechanical systems (MEMS) are nowadays widespread in the sensor market, with several different applications. New production techniques and ever smaller device geometries require a continuous investigation of potential failure mechanisms in such devices. This work presents an experimental on-chip setup to assess the geometry- and material-dependent strength of stoppers adopted to limit the deformation of movable parts, using an electrostatically actuated device. A series of comb-finger and parallel plate capacitors are used to provide a rather large stroke to a shuttle, connected to the anchors through flexible springs. Upon application of a varying voltage, failure of stoppers of variable size is observed and confirmed by post-mortem DC–V curves. The results of the experimental campaign are collected to infer the stochastic property of the strength of polycrystalline, columnar silicon films

Efeito do déficit hídrico no crescimento de acessos de Brachiaria brizantha Stap.

Foram avaliados quatro acessos de Brachiaria brizantha BRA 004308, BRA 004367, BRA 006866 e BRA 007277, em condições de déficit hídrico. Os tratamentos foram arranjados em esquema fatorial 4x2 (quatro acessos e duas condição hídrica) no delineamento em blocos ao acaso com quatros repetições. O experimento foi instalado em casa-de-vegetação e o déficit hídrico foi imposto durante quatro dias consecutivos, durante os quais foram feitas as análises de taxa de alongamento foliar (crn/perfilho/dia). No último dia de estresse foram feitas as análises de área foliar através do integrador foliar e a pesagem das amostras de raiz, folhas e hastes para determinação do peso seco. Para a área foliar específica, que expressa à razão entre área foliar e a massa seca de folhas, os acessos BRA 004367 e BRA 006866 em condições de estresse não diferiram da testemunha (P>0,05), indicando uma boa resposta destes acessos em manter sua área foliar mesmo em condições de déficit hídrico. Já os acessos BRA 004308 e BRA 007277 reduziram drasticamente suas AFE (P<0,05). Os acessos BRA 006866 e BRA 004367 foram os que se mostraram mais resistentes ao déficit hídrico

Selection of Panicum maximum hybrids in Brazil.

In search of new cultivars with differentials that better meet the needs of the cattle ranchers, crosses between five sexual plants and the apomictic accessions PM20, PM21 and Myiage were carried out at Embrapa Beef Cattle, Campo Grande, MS, Brazil. Accessions PM20 and PM21 were used to generate shorter hybrids for use under grazing and for crop-livestock integration; Myiage was used because of its ability to retain seeds.bitstream/item/210922/1/Selection-of-Panicum-maximum-hybrids-in-Brazil.pd

GISH-based comparative genomic analysis in Urochloa P. Beauv.

The genus Urochloa P. Beauv. [syn. Brachiaria (Trin.) Griseb.] comprises species of great economic relevance as forages. The genomic constitution for the allotetraploid species Urochloa brizantha (cv. Marandu) and Urochloa decumbens (cv. Basilisk) and the diploid Urochloa ruziziensis was previously proposed as BBB1B1, B1B1B2B2 and B2B2, respectively. Evidence indicates U. ruziziensis as the ancestral donor of genome B2 in U. decumbens allotetraploidy, but the origin of the genomes B and B1 is still unknown. There are diploid genotypes of U. brizantha and U. decumbens that ay be potential ancestors of the tetraploids. The aim of this study was to determine the genomic constitution and relationships between genotypes of U. brizantha (2x and 4x), U. decumbens (2x and 4x) and U. ruziziensis (2x) via genomic in situ hybridization (GISH). Additionally, chromosome number and genome size were verified for the diploid genotypes. The diploids U. brizantha and U. decumbens presented 2n = 2x = 18 chromosomes and DNA content of 1.79 and 1.44 pg, respectively. The GISH analysis revealed high homology between the diploids U. brizantha and U. decumbens, which suggests relatively short divergence time. The GISH using genomic probes from the diploid accessions on the tetraploid accessions? chromosomes presented similar patterns, highlighting the genome B1 present in both of the tetraploids. Based on GISH results, the genomic constitution was proposed for the diploid genotypes of U. brizantha (B1B1) and U. decumbens (B1&#8242;B1&#8242;) and both were pointed as donors of genome B1 (or B1&#8242;), present in the allotetraploid genotypes

Uso de miniestacas destacadas de espécies florestais para testes de patogenicidade.

A podridão e morte de miniestacas tem sido verificada na produção de mudas clonais de acácia-negra, eucalipto, erva-mate e pínus. Porém, vários fungos rotineiramente são encontrados em associação com a doença, dificultando sua etiologia. Assim, uma metodologia foi desenvolvida para se fazer o teste de patogenicidade com fungos isolados de miniestacas com podridão. A metodologia foi considerada eficiente, rápida e de fácil aplicação para determinar a patogenicidade de fungos em miniestacas destacadas