Forest biomass and wood consumption In the lower course of the Amazon: a case study of rhe Urubueua Island

Várzea and terra-firme forests in the lower course of the Amazon were compared in terms of forest structure, wood volume increments and forest biomass. The wood volume of várzea forests was smaller than that of terra-firme forests, particularly when severe human intervention such as the cultivation of açaí palm occurred. The difference was even greater in the forest weight comparison because of the lower wood density of várzea trees. These trees are not directly influenced by water stress during the dry season, while late wood with a high density is formed in the terra-firme trees. The annual forest disappearance area due to firewood for tile factories was estimated to be about 276 ha on the island investigated, which had an area of 36,200 ha. Assuming that the forests are rotatively cultivated every 25 to 30 years, the total deforestation area is 6,870-6,948 ha in 25 years and 8,244~8,337 ha in 30 years. This result means that the balance between forest biomass and utilization is not in crisis, however, this balance might be lost as long as substitutive energy such as electricity is not supplied.

Wood specific gravity of trees and forest types in the southern Peruvian Amazon

Estimates of terrestrial biomass depend critically on reliable information about the specific gravity of the wood of forest trees. The study reported on here was carried out in the southern Peruvian Amazon and involved collection of wood samples from trees (70 spp.) in intact forest stands. Results demonstrate the high degree of variability in specific gravity (ovendry weight/green volume) in trees at single locations. Three forest types (swamp, high terrace forest with alluvial soil, and sandy-soil forest) had values close to the average reported for tropical forest woods (.69). Two early successional forest types, which make up as much as 12% of the total vegetated area in this part of the Amazon, had values significantly lower (.40). An increase in specific gravity with increasing age of the tree, which has been reported in some spe cies of tropical-forest woods, is seen in a positive relationship between specific gravity and di ameter for a species prevalent in one plot. Increases in specific gravity with tree and forest age may be significant in estimating changes in carbon stores over time.

Floristic, edaphic and structural characteristics of flooded and unflooded forests in the lower Rio Purús region of central Amazonia, Brazil

Despite a natural history interest in the early 1900s, relatively little ecological research has been carried out in the Rio Purús basin of central Amazonia, Brazil. Here we describe a new study area in the region of Lago Uauaçú with an emphasis on the climate, forest structure and composition, and soil characteristics between adjacent unflooded (terra firme) and seasonally inundated forests; situated within both the white-water (várzea) and black-water (igapó) drainage systems that dominate the landscape. The climate was found to be typical of that of the central Amazon. Várzea forest soils had high concentrations of nutrients, while terra firme and igapó soils were comparatively nutrient-poor. Terra firme forests were the most floristically diverse forest type, whereas várzea was intermediate, and igapó the most species-poor. The Lecythidaceae was the most important family in terra firme while the Euphorbiaceae was the most important in both várzea and igapó. There were significant differences between forest types in terms of number of saplings, canopy cover and understorey density. In contrasting our results with other published information, we conclude that the Lago Uauaçú region consists of a typical central Amazonian forest macro-mosaic, but is a unique area with high conservation value due to the intimate juxtaposition of terra firme, várzea and igapó forests.

Coronary heart disease clinical manifestation and risk factors in Japanese immigrants and their descendents in the city of São Paulo

OBJECTIVE: To assess whether a difference exists in coronary heart disease clinical manifestations and the prevalence of risk factors between Japanese immigrants and their descendents in the city of São Paulo. METHODS: Retrospective analysis of coronary artery disease clinical manifestations and the prevalence of risk factors, comparing 128 Japanese immigrants (Japanese group) with 304 Japanese descendents (Nisei group). RESULTS: The initial manifestation of the disease was earlier in the Nisei group (mean = 53 years), a difference of 12 years when compared with that in the Japanese group (mean = 65 years) (P<0.001). Myocardial infarction was the first manifestation in both groups (P = 0.83). The following parameters were independently associated with early coronary events: smoking (OR = 2.25; 95% CI = 1.35-3.77; P<0.002); Nisei group (OR = 10.22; 95% CI = 5.64-18.5; P<0.001); and female sex (OR = 5.04; 95% CI = 2.66-9.52; P<0.001). CONCLUSION: The clinical presentation of coronary heart disease in the Japanese and their descendents in the city of São Paulo was similar, but coronary heart disease onset occurred approximately 12 years earlier in the Nisei group than in the Japanese group.

The relation of the concentration of macronutrients in the substrate and in the foliage to cell wall thickness and cellulose concentration in the xylem of slash pine (Pinus elliotti)

Sand culture experiments, using a sub-irrigation technique, were installed in order to find out the effects of the macronutrients N, P, K, Ca, Mg and S on growth, aspect, mineral composition, length of fibers, thickness of cell wall and cellulose concentration in slash pine. The aim was to obtain, under controlled conditions, basic information which could eventually lead to practical means designed to increase the rate of growth and to make of slash pine a richer source of cellulose. Nitrogen, Phosphorus, Potassium Experiment A 3 x 3 x 3 factorial design with two replicates was used. Nitrogen was supplied initially at the levels of 25, 50 and 100 ppm; phosphorus was given at the rates of 5, 10 and 20 ppm; potassium was supplied at the rates of 25, 50 and 100 ppm; six months after the experiment was started the first level for each element was dropped to zero. Others macro and all micronutrients were supplied at uniform rates. Fifteen hours of illumination per day were provided. The experimental technique for growing the slash pine seedlings proved quite satisfactory. Symptoms of deficiency of nitrogen, phosphorus and potassium were observed, described and recorded in photographs and water colors. These informations will help to identify abnormalities which may appear under field conditions. Chemical analysis of the several plant parts, on the other hand, give a valuable means to assess the nutritional status of slash pine, thus confirming when needed, the visual diagnosis. The correctness of manurial pratices, on the other hand, can be judged with the help of the analytical data tabulated. Under the experimental conditions nitrogen caused the highest increases on growth, as measured by increments in height and dry weights, whereas the effects of phosphorus and potassium were less marked. Cellulose concentration was not significantly affected by the treatments used. Higher levels of N seemed to decrease both length of fiber elements and the thickness of cell wall. The effects of P and K were not well defined. Calcium, Magnesium, Sulfur Experiment A 3 x 3 x 3 factorial design with two replicates was used. Calcium was supplied initially at the levels of 12.5, 25 and 50 ppm; magnesium and sulfur were given at the rates of 6, 12.5 and 25 ppm. Other macro and micronutrients were supplied at uniform rates, common to all treatments. Three months after starting the experiment the first level for each element was dropped to zero. Symptoms of deficiency of calcium, magnesium and sulfur were observed, described and recorded as in the case of the previous experiment. Chemical analysis were made, both for mineral content and cellulose concentration. Length of fibers and thickness of cell wall were measured. Both calcium and magnesium increase height, sulfur failing to give significant response. Dry weight was beneficially affected by calcium and sulfur. The levels of calcium, magnesium and sulfur in the needles associated with deficiency and maximum growth are comparable with those found in the literature. Cellulose concentration increased when the level of sulfur in the substrate was raised. The thickness of cell wall was negatively affected by the treatments; no effect was observed with regards to length of fibers.

Increasing the efficiency of utilization of soil and fertilizer phosphorus in the subtropical and tropical agricultural systems C

As a rule, soils of the subtropical and tropical regions, in which rainfall is not limiting, are acidic, and low in phosphorus, and, to a less extent, in other macro and micronutrients as well, such a sulfur, boron and zinc. The establishment of a permanent agricultural prac. tice therefore, demands relatively high usage of liming and phosphatic fertilization, to begin with. Several approaches, not mutually exclusive, could be used in order to increase the efficiency of utilization of soil and fertilizer phosphorus so that, goal of diminishing costs of production is reached. The use of liming materials bringing up pH to 6.0-6.5 causes the conversion of iron and aluminum phosphates to more available calcium phosphates; on the other hand, by raising calcium saturation in the exchange complex, it improves the development and operation if the root system which allows c or a higher utilization of all soil nutrients, including phosphorus, and helps of stand water deficits which may occur. The role of mycorrhizal fungi should be considered as a way of increasing soil and fertilizer P utilization, as well as the limitations thereof. Screening of and breeding for varieties with higher efficiency of uptake and utilization of soil and fertilizer phosphorus leads to a reduction in cost of inputs and to higher benefit/cost ratios. Corrective fertilization using ground rock phosphate helps to saturate the fixation power of the soil thereby reducing, as a consequence, the need for phosphorus in the maintenance fertilization. Maintenance fertilization, in which soluble phos-phatic sources are used, could be improved by several means whose performance has been proved: limimg, granula tion, placement, use of magnesium salts. Last, cost of phosphate fertilization could be further reduced, without impairing yields, through impairing yields, through changes in technology designed to obtain products better adapted to local conditions and to the availability or raw materials and energy sources.

New histochemical and morphological findings in the female genital tract of Boophilus microplus (Acari, Ixodidae): an attempt toward the elucidation of fertilization in ticks

At present not only is the site of fertilization in ticks still unknown but it is also unclear as to how this mystery can be solved. Signs of fertilization can be observed throughout the female genital tract and these can be clues for the elucidation of the unsolved questions relating to ticks fertilization. In Boophilus microplus (Canestrini, 1887) the most important signs are the following: the final eversion of the acrosomal canal in females ready for oviposition; the presence of small tubules, resembling the subplasmalemal process of the spermatozoon between the oviduct cells; budding nuclei throughout the female genital tract; and the two Feulgen and DAPI positive areas in the oocyte at vitelogenesis. These morphological characteristics suggest that fertilization takes place in the internal cylinder which extends from the uterus to the ovary itself.

Seasonal and diel variation in the fish assemblage of a Neotropical delta in southern Brazil

The objective of this study was to identify the patterns of seasonal and diel variation and the most important abiotic factors that influence variation in the fish assemblage of the Delta of the Jacuí River in southern Brazil. Seventy-two samples were collected over a one year period. Water temperature was the abiotic factor with the greatest influence on the distribution of the assemblage. The structure of the assemblage exhibited significant changes in terms of species abundance and biomass during the year, with the greatest abundance and biomass being observed during the autumn. There was no significant difference between day and night in terms of abundance, but biomass was significantly greater during the night than during the day.

Poliomyelitis: epidemiological aspects in Rio de Janeiro (Guanabara State) and adjacent areas in the period from 1961 to 1970

Based on the available data from the Hospital responsible for the care of paralitic poliomyelitis cases in Rio de Janeiro City (Guanabara State) and adjacent areas, and the laboratory studies carried out on these patients, the authors analize epidemiological aspects of poliomyelitis in a period of ten years (1961 to 1970). Paralitic poliomyelitis remains a public health problem, with a typical incidence in the less than 4 year age group. All three poliovirus types have been prevalent for at least one period of time during the last ten years. Trivalent oral vaccine has been used since 1961 but the vaccination levels achieved were not enough to a permanent control of the disease. A definite seasonal distribution of cases could not be observed with the available data. Active mass campaign vaccinations with previous motivation of all segments of the population, specially the low-income groups instead of passive waiting of children in Vaccination Centers seems to be the best aproach to control poliomyelitis in this area.

Lymnaea viatrix and Lymnaea columella in the neotropical region: a distributional outline

A review of lymnaeid samples collected by the author from 106 localities in Mexico, Cuba, Jamaica, Haiti, Dominican Republic, Puerto Rico, Martinique, Saint Lucia, Guatemala, Costa Rica, Panamá, Ecuador, Peru, Bolivia, Chile, Argentina, Uruguay andBrazil showed that one of them (from Ecuador) belonged to Lymnaea cousini Jousseaume, 1887, and all the others to either L. viatrix Orbigny, 1835 or l. columella Say, 1817. The ranges of L. viatrix and L. columella overlap in Middle America, and in northern and southern South America (Venezuela-Colombia-Ecuador and northeastern Argentina-Uruguay-southernmost Brazil, respectively). L. viatrix was the only species found in Peru west of the Andes and in Chile, and is supposed to have migrated eastward to Argentina via the Negro river basin. The range of L. columella in South America is discontinuous. The species has been recorded from Venezuela, Colombia and Ecuador and, east of the Andes, from latitudes 15º S (central-west Brazil) to 35º S (La Plata, Argentina). Such a gap may be attributed to either introduction from the northern into the southern area, or migration along the unsampled region on the eastern side of the Andes, or extinction in the now vacant area. No lymnaeids have been found so far in Brazil north of latitude 15º S and in the Guianas.

Trypanosoma cruzi: vertebrate and invertebrate cycles in the same mammal host, the opossum Didelphis marsupialis

Epimastigotes multiplying extracellularly and metacyclic trypomastigotes, stages that correspond to the cycle of Trypanosoma cruzi in the intestinal lumen of its insect vector, were consistently found in the lumen of the anal glands of opossums Didelphis marsupialis inoculated subcutaneously with infective feces of triatomid bugs.

Biomphalaria straminea and other planorbids in the Dominican Republic

In addition to previous records of Biomphalaria glabrata in the Dominican Republic, the southern central communities of Haina Arriba and Boca Chica, in the National District, are reported as new localities for that species; other species collected were Biomphalaria obstructa, B. helophila, Drepanotrema lucidum and Lymnaea viatrix. Biomphalaria straminea, a potential vector of Schistosoma mansoni, was found for the first time in the country, in the River Iguamo, just outside of the community of San Pedro de Macorís.

Leishmaniasis in Bolivia: II. The involvement of Psychodopygus yucumensis and Psychodopygus llanosmartinsi in the selvatic transmission cycle of Leishmania braziliensis braziliensis in a lowland subandean region

An epidemiological survey of the vectors of cutaneous leishmaniasis ("espúndia" type) was caried out in the Alto Beni region of Bolivia, an area of Andean foothills at the Eastern limit of the Amazonian lowlands. The climate is typical wet tropical (15ºS latitude). Anthropophilic phlebotomine sandfly species were sampled at 20 sites, all forested. The importance of species from the Psychodopygus group, already suspected as a vector in the transmission of Leishmania from the braziliensis complex, was confirmed by: 1) the aggressiveness and diversity of the species encountered (83% of catches, nine species), 2) the discovery of a new anthropophilic species, P. yucumensis and 3) the isolation of a strain of Leishmania braziliensis braziliensis indistinguishable from human strains from the same area, from two species, P. llanosmartinsi and P. yucumensis.

Rheotaxis of Biomphalaria glabrata on vertical substrates and its role in the recolonization of habitats treated with molluscicides

The authors observed specimens of Biomphalaria glabrata climbing up the vertical wall of a ditch against the current. The snails that showed this behavior during application of a molluscicide in the breeding site survived and probably played a role in repopulation, which was observed three months later. These observations motivated field and laboratory investigations which led the authors to conclude that: a) this species is able to climb vertical surfaces both in field and laboratory situations; b) the current of water, as a physical stimulus, is sufficient to trigger this behavior (rheotaxis); c) rheotaxis on vertical surfaces depends on the presence of a necessarily moderate current; d) there are indications that B. glabrata may undergo habituation with respect to rheotaxis on vertical walls, e) the relationship between rheotaxis and habituation should be considered as a factor causing snail grouping in water bodies which may contribute to their localization in the field; f) rheotaxis on vertical surfaces may facilitate population dispersal, and its occurrence should be considered when campaigns for the control of schistosomiasis transmission are planned. The authors present some proposals to avoid the manifestation of this behavior in some filed situations.