Surface Liming and Zinc Availability in a Long-Term Experiment under No-Till System

No-till (NT) system with crop rotation is one of the most effective strategies to improve agricultural sustainability in tropical and subtropical regions. To control soil acidity in NT, lime is broadcast on the surface without incorporation. The increase in soil pH due to surface liming may decrease zinc (Zn) availability and its uptake by crops. A field experiment was performed in Parana State, Brazil, on a loamy, kaolinitic, thermic Typic Hapludox to evaluate Zn bioavailability in a NT system after surface liming and re-liming. Dolomitic lime was surface applied on the main plots in July 1993 at the rates of 0, 2, 4, and 6 Mg ha-1. In June 2000, the main plots were divided in two subplots to study of the effect of surface re-liming at the rates of 0 and 3 Mg ha-1. The cropping sequence was soybean [Glycine max (L.) Merrill] (2001-2 and 2002-3), wheat (Triticum aestivum L.) (2003), soybean (2003-4), corn (Zea mays L.) (2004-5), and soybean (2005-6). Soil samples were collected at the following depths: 0-0.05, 0.05-0.10, and 0.10-0.20m, 10 years after surface liming and 3 years after surface re-liming. Soil Zn levels were extracted by four extractants: (i) 0.005molL-1 diethylenetriaminepentaacetic acid (DTPA) + 0.1molL-1 triethanolamine (TEA) + 0.01molL-1 calcium chloride (CaCl2) solution at pH7.3 (DTPA-TEA), (ii) 0.1molL-1 hydrochloric acid (HCl) solution, (iii) Mehlich 1 solution, and (iv) Mehlich 3 solution. Zinc concentrations in leaves and grains of soybean, wheat, and corn were also determined. Soil pH (0.01molL-1 CaCl2 suspension) varied from 4.4 to 6.1, at the 0- to 0.05-m depth, from 4.2 to 5.3 at the 0.05- to 0.10-m depth, and from 4.2 to 4.8 at the 0.10- to 0.20-m depth, after liming and re-liming. Zinc concentrations evaluated by DTPA-TEA, 0.1molL-1 HCl, Mehlich 1, and Mehlich 3 solutions were not changed as a result of lime rate application. Re-liming increased Zn concentrations extracted by 0.1molL-1 HCl at 0-0.05m deep and by DTPA-TEA at 0.05-0.10m deep. Surface-applied lime promoted a decrease in Zn concentrations of the crops, mainly in grains, because of increased soil pH at the surface layers. Regardless of the liming treatments, levels of Zn were sufficient to soybean, wheat, and corn nutrition under NT.Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq

Towards to the trans-bromination of 2-styrylpyridine with a palladacycle intermediary and structure analysis for trans-1,2-dibromo-2-styrylpyridine

The simple halogenation of alkynes in conventional organic reactions gives a blend of cis and trans isomers. It is proposed then, a synthesis of stereospecific halogenation of alkynes in trans position, using palladacycle as intermediaries. The recrystallization of the compound obtained by bromination of 2-Styrylpyridine, with cyclepalladium intermediary results in a single crystal, which is subjected to X-ray diffraction. The crystal packing is established through weak interactions of three types. The first one is of the type pi x pi interactions, from symmetry operation, between the centroids. The second one is of the type C-X center dot center dot center dot pi interactions. And the last type is an anomalous intermolecular interaction between halogens, C-X center dot center dot center dot X-C, with bond distances smaller than the sum of the van der Waals radii. The conformation on the C=C bond is trans and the dihedral angle between the aromatic rings is (with esd approximate) 18.1(3)degrees. (C) 2010 Elsevier B.V. All rights reserved

Atributos químicos de um Latossolo de cerrado sob plantio direto, de acordo com doses e formas de aplicação de calcário Chemical attributes of a cerrado Oxisol under no-tillage as affected by lime application methods and doses

Em áreas cultivadas em sistema plantio direto, a incorporação de calcário não é desejável. Com isso, o corretivo é aplicado sobre a superfície e concentra-se nos primeiros centímetros do solo. Para avaliar a correção da acidez de camadas mais profundas do perfil, com o passar do tempo, estudou-se o efeito de doses de calcário dolomítico (2,0, 4,9 e 7,8 t ha-1), aplicadas em superfície ou incorporadas, nos atributos químicos de um Latossolo Vermelho distrófico de cerrado. Amostras de terra foram coletadas nas profundidades de 0-5, 5-10, 10-20 e 20-40 cm, aos seis, 18 e 30 meses da aplicação do corretivo. Após seis meses, a calagem superficial promoveu aumento nos valores de pH, na saturação por bases e nos teores de Ca e Mg trocáveis, bem como diminuição nos teores de Al trocável e da acidez potencial (H + Al) somente na camada de 0-5 cm. Aos 18 e 30 meses da aplicação do calcário, tais efeitos estenderam-se até 10 cm. A incorporação do calcário proporcionou correção da acidez do solo até 20 cm de profundidade, a partir de seis meses após a sua aplicação. A calagem na superfície ou com incorporação não influenciou a correção da acidez do subsolo (20-40 cm). A saturação por bases na profundidade de 0-20 cm ficou abaixo da estimada pelo cálculo da dose do corretivo, mesmo com a incorporação do calcário, após 30 meses. A aplicação de calcário reduziu os teores de Mn e Fe no solo até à profundidade de 10 cm, quando realizada na superfície, e até 20 cm, quando incorporada, em conseqüência do aumento do pH proporcionado pela calagem. Mesmo assim, os teores de Mn e Fe no solo mantiveram-se acima dos limites considerados baixos.<br>Lime incorporation is not desirable in no-tillage systems. Lime is therefore applied on the soil surface, concentrating the product on the first few centimeters of the profile. We evaluated the aftereffects of dolomitic limestone (2.0, 4.9 and 7.8 t ha-1) application, either on surface or incorporated, on the deeper layers of a Typic Haplustox from the Brazilian Cerrado. Soil samples were collected at six, 18 and 30 months after liming at depths of 0-5, 5-10, 10-20, and 20-40 cm. After six months the pH, base saturation (BS), and Ca and Mg concentration increased after surface liming, while both Al concentration and potential acidity (H + Al) were reduced only down to 5 cm. These effects extended down to 10 cm when evaluated at 18 and 30 months after liming. Lime incorporation decreased the soil acidity to a depth of up to 20 cm six months after the application. Surface or incorporated liming did not influence the soil acidity in the subsoil (20 - 40 cm). Base saturation at 0-20 cm depth was lower than the estimated BS, even 30 months after liming. Manganese and Fe concentration decreased at 10 cm depth after surface liming and decreased at 20 cm after lime incorporation as a consequence of the pH increase. Still, the concentration of these micronutrients remained above the limit considered critical for plants

Humanización en contexto pediátrico: el papel de los payasos en la mejora del ambiente vivido por el niño hospitalizado Interface

Valorizando a importância dos aspetos psicossociais da internação pediátrica, e procurando a criança “por detrás” do corpo doente, vários hospitais têm investido na humanização de espaços, rotinas e atmosfera, procurando promover ambientes acolhedores e atenuantes das experiências negativas vividas pela criança (e família) durante a internação. A par de uma tentativa de sistematização de alguns dos esforços realizados até a data em nível da definição do conceito de “humanização” – nomeadamente em contexto pediátrico –, reflete-se acerca das potencialidades de alguns programas existentes nesse contexto, nomeadamente aqueles que aliam a arte, a recreação, o lazer e o humor como meios privilegiados de comunicação e expressão. Entre estes, destaca-se a intervenção dos palhaços de hospital, como promotora da livre expressão da criança, da sua autonomia, criatividade, exploração e conhecimento do mundo e consequente desenvolvimento psicossocial.In order to place value on the importance of psychosocial aspects of pediatric hospitalization, and to seek the child “behind” the sick body, many hospitals have been investing in humanizing their spaces, routines, and atmospheres aiming welcoming environments that will reduce the negative experiences of the children and their families during the hospital stay. In this paper, an attempt was made to systematize some of the efforts undertaken so far to define the concept of “humanization” specifically in the pediatric context. Reflections on the potential of some existing programs within this context are also provided, specifically those that combine art, recreation, leisure activities and humor as preferred means of communication and expression. Among these, interventions by hospital clowns are highlighted as promoters of free expression among children, along with autonomy, creativity, exploration, and knowledge of the world, with consequent psychosocial development.Valorizando la importancia de los aspectos psicosociales de la internación pediátrica y buscando al niño “por detrás” del cuerpo enfermo, varios hospitales han invertido en la humanización de sus espacios, rutinas y atmósfera, promovendo ambientes acogedores y atenuadores de las experiencias negativas vividas por el niño durante la internación. En el presente artículo, juntamente con un intento de sistematización de esfuerzos hasta la fecha en el ámbito de la definición de “humanización”, principalmente en el contexto pediátrico, se reflexiona sobre las potencialidades de algunos programas existentes, principalmente aquellos que unen el arte, la recreación, el ocio y el humor como medios privilegiados de comunicación y de expresión. Entre ellos, los autores destacan la intervención de los payasos de hospital, como promotora de la libre expresión del niño, de su autonomía, creatividad, exploración y conocimiento del mundo y su desarrollo psicosocial.info:eu-repo/semantics/publishedVersio