Influência do extrato pirolenhoso na calda de pulverização sobre o teor foliar de nutrientes em limoeiro 'Cravo'

Com o objetivo de avaliar o efeito da presença do extrato pirolenhoso (EP) na calda de pulverização sobre o teor foliar de nutrientes de limoeiro 'Cravo' (Citrus limonia Osbeck), foi desenvolvido um experimento com seis tratamentos e quatro repetições, em blocos ao acaso, em ambiente protegido. Os tratamentos constituíram da pulverização das soluções: T0 = água; T1 = solução de micronutrientes sem EP; T2 = solução de micronutrientes + EP (1cm³ dm-3); T3 = solução de micronutrientes + EP (2 cm³ dm-3); T4 = solução de micronutrientes + EP (5cm³ dm-3); T5 = solução de micronutrientes + EP (10 cm³ dm-3). A solução de micronutrientes foi preparada com sulfatos de Cu, Fe, Mn, Zn (250 mg dm-3 do elemento) e ácido bórico (42,5 mg dm-3 de B). As plantas foram cultivadas em tubetes cônicos de 0,280 dm³, com substrato sem a adição de micronutrientes na formulação. As soluções foram pulverizadas uma única vez, aos 140 dias após o plantio (DAP), momento em que as plantas apresentavam aproximadamente 20 cm de altura. Ao final do experimento (160 DAP), quantificaram-se a massa seca e os teores de macro e micronutrientes da parte aérea e sistema radicular. A presença do extrato pirolenhoso na solução de micronutrientes não interferiu na concentração foliar de B, Fe e Zn em mudas de limoeiro 'Cravo'. Entretanto, na concentração de 10 cm³ dm-3, aumentou a concentração foliar de Cu e Mn. Observou-se também que as plantas pulverizadas com soluções contendo EP (1 a 10 cm³ dm-3) + micronutrientes apresentaram menor teor de Fe e maior teor de Ca no sistema radicular.

Influence of sugar cane burning on aerosol soluble ion composition in Southeastern Brazil

Seasonal variability in the major soluble ion composition of atmospheric particulate matter in the principal sugar cane growing region of central São Paulo State indicates that pre-harvest burning of sugar cane plants is an important influence on the regional scale aerosol chemistry. Samples of particulate matter were collected between April 1999 and February 2001 in coarse (> 3.5 mum) and fine (< 3.5 mum) fractions, and analysed for HCOO-, CH3COO-, C2C42-, SO42- . Results indicated that the principal sources of the aerosols investigated NO3-, Cl-, Na+, K+, NH4+, Mg2+ and Ca2+ were local or regional in nature (scale of tens to a few hundreds of km), and that differences between air masses of varying origins were small. Fine particles were typically acidic, containing secondary nitrates, sulphates and organic species. Coarse fraction concentrations were mainly influenced by physical parameters (wind speed, movement of vehicles and surface condition) affecting rates of re-suspension, although secondary nitrate and sulphate were also present in the larger particles.Concentrations of all measured species except sodium and chloride were higher during the burning season. Although concentrations were lower than often found in polluted urban environments, the massive increases during much of the year, due to a single anthropogenic activity (sugar cane burning) are indicative of a very large perturbation of the lower troposphere in the region relative to the natural condition. These aerosols are suspected of promoting respiratory disease. They also represent an important mechanism for the tropospheric transport of species relevant to surface acidification (sulphates, nitrates, ammonium and organic acids) and soil nutrient status (potassium, nitrogen, ammonium, calcium), so their impact on fragile natural ecosystems (following deposition) needs to be considered. (C) 2004 Elsevier Ltd. All rights reserved.

Geologia e Caracterização Tecnológica do Minério de Manganês da Mina Córrego do Cocho, Itapira (SP)

The objects of this study are three manganese ore deposits and one mine derived from lateritic weathering of gondites (spessartine quartzites). These deposits are associated with Mn-rich garnet metasediments of the Itapira Group (Paleoproterozoic) and the reserves were estimated at approximately 2.0 × 10 6 tons with an average grade of 23% MnO 2. The ore minerals are cryptomelane, pyrolusite, lithiophorite, spessartine and psilomelane. Several crystal shapes and textural characteristics were identifi ed in this study, which are related to the degree of liberation, as confi rmed by heavy media separation method. In this study, we determined the main characteristics of the liberation of manganese, which is concentrated in the fi ne grain-size fraction and is lost during ore dressing. Therefore, the low average content of MnO 2 (28%) is due to this loss, whereas at grain size of minus 0.074 mm, contents near 40% MnO 2 were observed. This suggests that the ore can be used for manufacturing manganese sulphate fertilizers. A comparative study with the ore deposits located at Ouro Fino (MG), mainly with the Caneleiras mine, showed that higher degree of liberation occurs in the coarse grain-size fractions (0.84 to 0.074 mm with MnO 2 content of 38%). As a consequence, the ore can be used for manufacturing Fe-Si-Mn alloys.

Mineralizações auríferas hospedadas na faixa metavulcano-sedimentar Jacuí-Bom Jesus da Penha - Sudoeste de Minas Gerais

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Uso de sub-produtos da fabricação de carvão vegetal na formação do porta-enxerto limoeiro 'cravo' em ambiente protegido

Pós-graduação em Agronomia (Produção Vegetal) - FCAV

Síntese de microesferas de quitosana para aplicação em liberação controlada de drogas pelo método de atomização e coagulação

Chitosan is a natural biodegradable polymer with great potential for pharmaceutical applications due to its biocompatibility, high charge density , nontoxicity and mucoadhesion. Gel formation can be obtained by the interactions of chitosans with low molecular counterions such as polyphosphates, sulphates and crosslinking with glutaraldehyde. This gelling property of chitosan allows a wide range of applications such as coating of pharmaceuticals and food products, gel entrapment of biochemicals, whole cells, microorganisms and algae. One of its main applications is the synthesis of microspheres for coating of pharmaceuticals , magnetic particles an other substances. In such a way, we can build targeted drug delivery systems. In the present work, we applied the method of spraying and coagulation. The resulting microspheres, then, were characterized by optical microscopy