Soil organic carbon stock change due to land use activity along the agricultural frontier of the southwestern Amazon,Brazil, between 1970 and 2002

The southwestern portion of the Brazilian Amazon arguably represents the largest agricultural frontier in the world, and within this region the states of Rondônia and Mato Grosso have about 24% and 32% of their respective areas under agricultural management, which is almost half of the total area deforested in the Brazilian Amazon biome. Consequently, it is assumed that deforestation in this region has caused substantial loss of soil organic carbon (SOC). In this study, the changes in SOC stocks due to the land use change and management in the southwestern Amazon were estimated for two time periods from 1970–1985 and 1985–2002. An uncertainty analysis was also conducted using a Monte Carlo approach. The results showed that mineral soils converted to agricultural management lost a total of 5.37 and 3.74 Tg C yr^?1 between 1970–1985 and 1985–2002, respectively, along the Brazilian Agricultural Frontier in the states of Mato Grosso and Rondônia. Uncertainties in these estimates were ±37.3% and ±38.6% during the first and second time periods, respectively. The largest sources of uncertainty were associated with reference carbon (C) stocks, expert knowledge surveys about grassland condition, and the management factors for nominal and degraded grasslands. These results showed that land use change and management created a net loss of C from soils, however, the change in SOC stocks decreased substantially from the first to the second time period due to the increase in land under no‐tillage.     

The recombinant protein rSP03B is a valid antigen for screening dog exposure to Phlebotomus perniciosus across foci of canine leishmaniasis

The frequency of sandfly–host contacts can be measured by host antibody levels against sandfly salivary proteins. Recombinant salivary proteins are suggested to represent a valid replacement for salivary gland homogenate (SGH); however, it is necessary to prove that such antigens are recognized by antibodies against various populations of the same species. Phlebotomus perniciosus (Diptera: Psychodidae) is the main vector of Leishmania infantum (Trypanosomatida: Trypanosomatidae) in southwest Europe and is widespread from Portugal to Italy. In this study, sera were sampled from naturally exposed dogs from distant regions, including Campania (southern Italy), Umbria (central Italy) and the metropolitan Lisbon region (Portugal), where P. perniciosus is the unique or principal vector species. Sera were screened for anti‐P. perniciosus antibodies using SGH and 43‐kDa yellow‐related recombinant protein (rSP03B). A robust correlation between antibodies recognizing SGH and rSP03B was detected in all regions, suggesting substantial antigenic cross‐reactivity among different P. perniciosus populations. No significant differences in this relationship were detected between regions. Moreover, rSP03B and the native yellow‐related protein were shown to share similar antigenic epitopes, as canine immunoglobulin G (IgG) binding to the native protein was inhibited by pre‐incubation with the recombinant form. These findings suggest that rSP03B should be regarded as a universal marker of sandfly exposure throughout the geographical distribution of P. perniciosus.     

Effects of Gonadotropins on Motility of Human Ovary

THE occurrence of smooth muscle cells in the ovaries of many mammalian species suggests their possible function in the rupture of the ripe follicle by their contractions¹. In the rabbit, pig and sheep ovarian follicles, true smooth muscle cells are present in either or both the theca interna and externa. In women, follicles are surrounded by a network of reticular fibres and cells which resemble smooth muscle cells without fibrils². In a recent report, the ovaries of the cat have not only demonstrated spontaneous contractions in vitro but have also responded to adrenergic stimulation³. On the basis of these findings and in view of the fact that the stromal region of the ovaries of many species, including man, has adrenergic innervation, it has been proposed that contractions of the fibromuscular tissue may play a role in rupture of the follicle and extrusion of the ova³. In this report we describe changes in human intraovarian pressure which seem to result from contraction of the surrounding fibromuscular tissue. In some women marked changes in intraovarian pressure were observed after administration of human menopausal gonadotrophin and chorionic gonadotrophin. The study was carried out in six women of reproductive age who had to undergo abdominal surgery for correction of tubal occlusion (four patients) or tubal ligation. The two patients undergoing tubal ligation were on contraceptive pills for 3–5 years before the operation.     

The First Stages of Pre-harvest 'Peel Pitting' Development in 'Encore' Mandarin. An Histological and Ultrastructural Study

‘Peel pitting’ in the flavedo (the coloured epicarp)of ‘Encore’ mandarin arises as chlorotic spots.These spots correspond to parenchymal flattening and collapseof a variable number of sub-epidermal cell layers, which increasein parallel with the epidermis, extending between apparentlyhealthy zones. The first signs of cellular damage are associatedwith internal membrane disorganization of the plastids. Greatvesiculation of the cytoplasm occurs, followed by degradationof cytoplasmic membranes and accumulation of abundant osmiophilicmaterial, yielding amorphous and dense masses. The disorderstarted by September. Spotting was only observed on the outerside of the fruit and on portions of the rind most exposed toexternal factors. Radiation and high temperature of the rindover long periods may induce localized dehydration, plasmolysisand cell collapse.Copyright 1999 Annals of Botany Company Citrus, ‘Encore’ mandarin, pre-harvest pitting, peel disorder, histology, ultrastructure.