Teores de aminoácidos e fenóis em plântulas de algodoeiro (Gossypium hirsutum L. cv. 'IAC-17') sob ação de reguladores vegetais

This research deals with the effects of exogenous growth regulators on dry weight, contents of aminoacids and phenolic compounds in leaves of cotton plants. To study the influence of the chemicals, cotton seeds were immersed during 22 hours in water solutions of (2-chloroethyl) trimethylammonium chloride (CCC) at concentration of 2000 ppm, succinic acid-2,2-dimethylhydrazide 4000 ppm,gibberellic acid 100 ppm, indolylacetic acid (IAA) 100 ppm, and water as check treatment. CCC 2000 ppm increased the dry weight in the leaves of cotton plants. This growth retardant increased the content of free aminoacids in cotton leaves. IAA 100 ppm reduced the concentration of aminoacids in the treated plants. The contents of phenolic compounds in leaves of cotton was increased by CCC, in relation to check treatment.Verificaram-se os efeitos da aplicação de reguladores de crescimento na porcentagem de materia seca, aminoácidos livres totais e compostos fenólicos nas folhas de algodoeiro 'lAC-l7'. Para se estudar a ação dos fitoreguladores, sementes de algodoeiro foram imersas durante 22 horas em soluções aquosas de cloreto (2-cloroetil) trimetilamônio (CCC) na concentração de 2000 ppm, ácido succínico-2,2-dimetilhidrazida 4000 ppm, ácido giberélico 100 ppm, ácido indolilacético (IAA) 100 ppm e água como controle. Plântulas com 33 dias de idade foram coletadas, sendo em seguida realizada a amostragem de folhas em laboratório, para efetuar-se a extração dos compostos. Observou-se que CCC 2000 ppm promoveu aumento no peso seco das folhas de algodoeiro. Esse retardador de crescimento aumentou o conteúdo de aminoácidos livres totais nas folhas estudadas. IAA 100 ppm reduziu a concentração de aminoácidos, nas plantas tratadas. O teor de fenóis totais nas folhas de Gossypium hirsutum foi aumentado por efeito do CCC com relação ao controle

HighP–TNano-Mechanics of Polycrystalline Nickel

We have conducted highP–Tsynchrotron X-ray and time-of-flight neutron diffraction experiments as well as indentation measurements to study equation of state, constitutive properties, and hardness of nanocrystalline and bulk nickel. Our lattice volume–pressure data present a clear evidence of elastic softening in nanocrystalline Ni as compared with the bulk nickel. We show that the enhanced overall compressibility of nanocrystalline Ni is a consequence of the higher compressibility of the surface shell of Ni nanocrystals, which supports the results of molecular dynamics simulation and a generalized model of a nanocrystal with expanded surface layer. The analytical methods we developed based on the peak-profile of diffraction data allow us to identify “micro/local” yield due to high stress concentration at the grain-to-grain contacts and “macro/bulk” yield due to deviatoric stress over the entire sample. The graphic approach of our strain/stress analyses can also reveal the corresponding yield strength, grain crushing/growth, work hardening/softening, and thermal relaxation under highP–Tconditions, as well as the intrinsic residual/surface strains in the polycrystalline bulks. From micro-indentation measurements, we found that a low-temperature annealing (T < 0.4 Tm) hardens nanocrystalline Ni, leading to an inverse Hall–Petch relationship. We explain this abnormal Hall–Petch effect in terms of impurity segregation to the grain boundaries of the nanocrystalline Ni

Processos de democracia direta: sim ou não? Os argumentos clássicos à luz da teoria e da prática

Regularmente surgem controvérsias sobre os processos de democracia direta, dos quais os mecanismos mais frequentes são a iniciativa popular, o plebiscito e o referendo. Por um lado, há autores que defendem a posição de que essas instituições tornam o jogo político mais lento, caro, confuso e ilegítimo; outros defendem a posição contrária e argumentam que processos de democracia direta são fundamentais para os cidadãos e a qualidade da democracia. O presente estudo analisa esse tema em torno de sete questões, baseadas em considerações teóricas e pesquisas empíricas: 1. A questão entre o minimalismo e o maximalismo democrático; 2. A concorrência entre maioria e minoria; 3. A concorrência entre as instituições representativas e os processos de democracia direta; 4. A questão da competência dos cidadãos; 5. A questão dos efeitos colaterais dos processos de democracia direta; 6. A questão do tamanho do eleitorado; 7. A questão dos custos dos processos de democracia direta. As sete questões são analisadas a partir de uma revisão bibliográfica que considera tanto fontes nacionais como internacionais. O estudo mostra que os processos de democracia direta podem ser um complemento para as instituições representativas em um sistema democrático. O bom desempenho dos plebiscitos, referendos e iniciativas populares depende tanto da regulamentação destes como também do desempenho das outras instituições políticas e da situação socioeconômica de um país. O estudo permite ampliar e aprofundar o debate sobre processos de democracia direta no Brasil

Polar Stratospheric Clouds during SOLVE/THESEO: Comparison of Lidar Observations with in Situ Measurements

Polar stratospheric clouds (PSCs) were observed on several flights during the 1999/2000 SOLVE/THESEO mission. Here we present an analysis of PSC size distribution, composition, and particle phase based on near coincident measurements using the Multiangle Aerosol Spectrometer Probe (MASP) and Focused Cavity Aerosol Spectrometer (FCAS III) on board the ER-2 as well as lidar instruments on board the DC-8 and Falcon aircrafts. We calculate the aerosol backscatter ratios and aerosol depolarization ratios at infrared and visible wavelengths based on the particle size distributions measured by the MASP and FCAS III instruments. We then compare our calculations to observed lidar measurements taken from on board the DC-8 and Falcon aircraft, which flew the same flight paths as the ER-2 on 20 January and 3 February 2000, respectively. Our comparison shows that calculations based on the mixed clouds containing small (submicrometer) spherical particles and large (2.5–22 μm diameter) nonspherical particles seen by the FCAS III and MASP are consistent with lidar observations. Our analysis shows that the infrared aerosol depolarization ratio must be measured to detect and identify mixed PSC clouds and that relying only on measurements of depolarization in the visible causes incorrect identification of mixed clouds as solution droplets. This study suggests that mixed clouds of supercooled ternary solutions were observed in coexistence with larger solid nitric acid hydrate particles

Evaluating the role of NAT, NAD, and liquid H2SO4/H2O/HNO3 solutions in Antarctic polar stratospheric cloud aerosol: Observations and implications

Journal of Geophysical Research, Vol. 102, No. D11 pp. 13,255-13,282.Airborne measurements of total reactive nitrogen (NOy) and polar stratospheric cloud (PSC) aerosol particles were made in the Antarctic (68 degrees S) as part of the NASA Airborne Southern Hemisphere Ozone Experiment/Measurements for Assessing the Effects of the Stratospheric Aircraft (ASHOE/MAESA) campaign in late July 1994..