Growth and physiological characteristics of the weed false johnsongrass ( Sorghum arundinaceum (Desv.) Stapf)

ABSTRACT Sorghum arundinaceum (Desv.) Stapf is a weed that belongs to the Poaceae family and is widespread throughout Brazil. Despite the frequent occurrence, infesting cultivated areas, there is little research concerning the biology and physiology of this species. The objective of this research was to evaluate the growth, carbon partitioning and physiological characteristics of the weed Sorghum arundinaceum in greenhouse. Plants were collected at regular intervals of seven days, from 22 to 113 days after transplanting (DAT). In each sample, we determined plant height, root volume, leaf area and dry matter, and subsequently we perfomed the growth analysis, we have determined the dry matter partitioning among organs, the accumulation of dry matter, the specific leaf area, the relative growth rate and leaf weight ratio. At 36, 78 and 113 DAT, the photosynthetic and transpiration rates, stomatal conductance, CO2 concentration and chlorophyll fluorescence were evaluated. The Sorghum arundinaceum reached 1.91 in height, with slow initial growth and allocated much of the biomass in the roots. The photosynthetic rate and the maximum quantum yield of FSII are similar throughout the growth cycle. At maturity the Sorghum arundinaceum presents higher values of transpiration rate, stomatal conductance and non-photochemical quenching coefficient (NPQ).

Cantaloupe melon ( Cucumis melo L.) conservation using hydrocooling

ABSTRACT Maintaining cantaloupe melon at field temperature impairs conservation as it speeds up cell metabolism and transpiration, and, consequently, reduces shelf life. This study aimed to evaluate the conservation of Torreon hybrid cantaloupe using the hydrocooling treatment. Fruits were harvested at the commercial maturity stage (60 days after planting), in the morning, at the Nova California Farm, municipality of Mossoró-RN, in September 2007. One set of fruit was immersed in chilled water at 5 ºC for 5 min, at the packing house, while the remaining set was not hydro cooled. Then, both sets (treated and untreated with hydrocooling) were pre-cooled in air forced tunnels at 7 ºC, until the temperature in the pulp reached 10 ºC. Both fruit sets were stored for 0, 14, 21, 28 and 35 days under modified atmosphere at 3 ± 1 oC and 90 ± 5% RH. After each storage period, the fruits were incubated in an atmosphere-controlled chamber at 20 ± 2 oC and 80 ± 5% de RH, for seven days. The following characteristics were evaluated: external and internal appearance, mass loss, soluble solids, firmness and titrable acidity. The experiment was arranged in a completely randomized split-plot design with four replications of three fruits. The plots consisted of the hydrocooling conditions (with and without fruit soaking in chilled water), and the sub-plots consisted of the storage times (0, 14, 21, 28 and 35 days).The treatment with hydrocooling was efficient in keeping the firmness and soluble solids of the fruits and shortened the pre-cooling time in the cooling tunnel. However, hydrocooling did not increase fruit shelf-life.

L'APPORT DE LA SOCIOLOGIE PRAGMATIQUE FRANÇAISE AUX ÉTUDES CRITIQUES EN MANAGEMENT

La sociologie pragmatique française (SP), inspirée des travaux de Luc Boltanski et Laurent Thévenot, est de plus en plus utilisée par les études organisationnelles en management. Pourtant, la dimension critique de cette approche n'a pas encore été intégrée au profit de la connaissance en management et organisations (MOK). Dans cet article, nous explicitons l'apport que cette sociologie peut représenter pour les études critiques en management (CMS). En tant que science de la science des acteurs, nous suggérons que la SP est fertile pour développer une approche de performativité critique. En particulier, nous démontrons que l'approche permet de mettre en lumière les nouvelles formes de domination plus complexes s'exerçant dans les organisations contemporaines. En utilisant des études empiriques d'organisations mobilisant la SP, nous montrons comment les concepts de compromis et d'épreuve développés par cette approche présentent un outillage permettant de renouveler la critique des organisations au profit de la MOK.

ESTRADAS LÍQUIDAS, COMÉRCIO SÓLIDO: ÍNDIOS E REGATÕES NA AMAZÔNIA (SÉCULO XIX)

O artigo analisa as relações entre os índios e os comerciantes ambulantes que, na Amazônia do século XIX, eram conhecidos como regatões. Com base em documentos da época, constata-se que nem sempre os índios foram vítimas ingênuas e passivas diante dos regatões e que é necessário enfatizar a dimensão simbólica das trocas, a fim de recuperar o protagonismo indígena nas relações estabelecidas com os comerciantes e com as mercadorias que eles vendiam.

Teste de susceptibilidade do percevejo, Cimex lectularius L. (Hemiptera, Cimicidae) ao DDT em Belo Horizonte, MG (Brasil)

O nível de susceptibilidade de percevejos adultos, Cimex lectularius, ao DDT, em Belo Horizonte, Minas Gerais (Brasil), foi determinado durante o período de 1985 a 1986. Os resultados indicaram, para os insetos testados, que uma dose de 4,0% do inseticida não foi suficiente para matar 55% dos insetos. Os dados permitem concluir que existem colonias de percevejos resistentes ao DDT em Belo Horizonte.