Aspectos físico-químicos e biológicos relacionados à ocorrência de Biomphalaria glabrata em focos litorâneos da esquistossomose em Pernambuco

This study analyzes the physico-chemical and biological parameters of freshwater aquatic environments in coastal areas of the State of Pernambuco, Brazil, where snail vector foci and cases of schistosomiasis have been recorded. The tests were carried out using standard methods and sediments were analyzed using the X-ray fluorescence technique. The micro-algae were analyzed using conventional microscopy. The most abundant chemical elements in the sediments were Fe, Ca, Si and Al and there were high concentrations of electrolytes in comparison with data published in the literature. The mean values for salinity (7.7 g/L) and sulfate (489 mg/L) were much higher than normal for freshwater environments. The micro-algae identified are those that inhabit environments with higher levels of salinity. The snail Biomphalaria glabrata seems, therefore, to be more tolerant to salty environments and this constitutes a risk of spread of schistosomiasis.

Determinação da composição isotópica de estrôncio em águas naturais: exemplos de sua aplicação em águas subsuperficiais da zona costeira na região Bragantina-PA

Analytical procedures used for determining the concentrations and isotope composition of strontium in subsurface waters, by mass spectrometry, are described. Sampling was performed in coastal plateaus, salt marsh and mangrove environments in the coastal region of Pará. Coastal plateau waters have delta87Sr between 1.51 and 6.26‰ and Sr concentration bellow 58 ppb. Salt marsh waters show delta87Sr between 0.55 and 0.90‰ and Sr concentration between 93 and 114 ppm, while mangrove waters have delta87Sr‰ around zero and Sr concentration above 15 ppm. Differences in the 87Sr/86Sr ratio in these subsurface waters are detected, as well as seasonal variations in the coastal pleteau waters.

Size distribution of atmospheric particulate ionic species at a coastal site in Portugal

A Berner impactor was used to collect size-differentiated aerosol samples from March to August 2003 in the city of Aveiro, on the Portuguese west coast. The samples were analysed for the main water-soluble ion species. The average concentration of sulphate, nitrate, chloride and ammonium was 6.38, 3.09, 1.67 and 1.27 µg m-3, respectively. The results show that SO4(2-) and NH4+ were consistently present in the fine fraction < 1 µm, which represents, on average, 72 and 89% of their total atmospheric concentrations, respectively. The NO3-particles were concentrated in the coarse size. Chloride presented the characteristic coarse mode for marine aerosols. During some spring/summer events, an ammonium surplus was observed (NH4+/SO4(2-) molar ratios > 2), possibly due to greater availability of ammonia coming from agricultural activities or from the neighbouring chemical industrial complex. During the remaining periods, the aerosol was found to be somewhat acidic and predominantly in the form of ammonium bisulphate (NH4+/SO4(2-) molar ratios = 0.5-1.25). Samples collected under a major or exclusive influence of maritime air masses were essentially constituted by coarse particles with enrichment in sea salt, while for air masses of continental origin the contribution of water-soluble ionic species in the fine mode was more pronounced.

Corrosion of steel reinforced concrete in the tropical coastal atmosphere of Havana City, Cuba

The influence of chloride deposition rate on concrete using an atmospheric corrosion approach is rarely studied in the literature. Seven exposure sites were selected in Havana City, Cuba, for exposure of reinforced concrete samples. Two significantly different atmospheric corrosivity levels with respect to corrosion of steel reinforced concrete were observed after two years of exposure depending on atmospheric chloride deposition and w/c ratio of the concrete. Changes in corrosion current are related to changes in chloride penetration and chloride atmospheric deposition. The influence of sulphur compound deposition could also be a parameter to consider in atmospheric corrosion of steel reinforced concrete.

Substrate with Organosuper® for cucumber seedlings formation in protected environments and polystyrene trays

Culture environments, trays and doses of organic compost were evaluated in the formation of cucumber seedlings (Cucumis sativus L.). Five environmental conditions were tested: (A1) a greenhouse with height of 2.5 m, covered with polyethylene film, (A2) nursery with height of 2.5 m, monofilament fabric, 50% shading, (A3) nursery with height of 2.5 m, heat-reflective screen, 50% shading, (A4) nursery with a height of 1.8 m, covered with coconut tree straw and (A5) greenhouse with height of 4.0 m, covered with polyethylene film, with zenith opening and thermo-reflective cloth under the plastic. Trays of 72 (R1) and 128 (R2) cells were filled with 93% soil and 7% organic compound (S1), 86% soil and 14% organic compound (S2) and 79% soil and 21% organic compound (S3). It was used a randomized design in split-split-plot scheme, with five replicates (environments x trays x substrates). The greenhouses provide the best environments for the formation of cucumber seedlings. A tray of 72 cells is the best container, promoting more vigorous seedlings in substrate with soil and 7 or 14% organic compound.

Formation of beetroot seedlings in different protected environments, substrates and containers in Aquidauana region, State of Mato Grosso do Sul, Brazil

This study with beetroot seedlings, cultivar Top Tall Early Wonder, was carried out at the State University of Mato Grosso do Sul (UEMS/Aquidauana), from October to November 2008. Three environments of cultivation were used: greenhouse; nursery with monofilament screen of 50 % of shading; and nursery with aluminized thermal reflective screen of 50% of shading. In these environments, three polystyrene trays of 72, 128 and 200 cells, filled with four substrates, were tested: soil; Plantmax®; coconut fiber and vermiculite. There were no replication environments and then each one was considered an experiment alone. For each environment, it was adopted a completely randomized design in factorial scheme 3x4 (three trays x four substrates), with four replications, performing individual analysis of variance and joint analysis of experiments for environment comparisons. The monofilament screen is the best environment for seedlings produced in tray of 72 cells, and the greenhouse was the best environment for seedlings produced in trays of 128 cells. The best seedlings were formed in the tray of 72 cells. Vermiculite was the best substrate.

Probabilistic structure of an annual extreme rainfall series of a coastal area of the State of São Paulo, Brazil

This study aimed to describe the probabilistic structure of the annual series of extreme daily rainfall (Preabs), available from the weather station of Ubatuba, State of São Paulo, Brazil (1935-2009), by using the general distribution of extreme value (GEV). The autocorrelation function, the Mann-Kendall test, and the wavelet analysis were used in order to evaluate the presence of serial correlations, trends, and periodical components. Considering the results obtained using these three statistical methods, it was possible to assume the hypothesis that this temporal series is free from persistence, trends, and periodicals components. Based on quantitative and qualitative adhesion tests, it was found that the GEV may be used in order to quantify the probabilities of the Preabs data. The best results of GEV were obtained when the parameters of this function were estimated using the method of maximum likelihood. The method of L-moments has also shown satisfactory results.

Production of baruzeiro seedling in different protected environments and substrates

The high seedlings quality is essential for deployment of homogeneous orchards. This study evaluated the baruzeiro (Dipteryx alata Vog) seedlings formation on different substrates within protected environments. It was used substrates with100% of cattle manure; 100% of cassava stems; 100% of vermiculite; 50% of cattle manure + 50% of cassava stems; 50% of cattle manure + 50% of vermiculite; 50% of cassava stems + 50% of vermiculite; and + ⅓ of cattle manure + ⅓ of cassava stems + ⅓ of vermiculite. These substrates were tested in protected areas: greenhouse; black shade net of 50% shading; and aluminized thermo-reflective screen of 50% shading. A completely randomized experimental design with five replicates of four plants was adopted. Initially, data were submitted to analysis of individual variance of the substrates, in each environment of cultivation, then performing the evaluation of the residual mean square and the analysis of these environments together for comparison. The best substrate for baruzeiro seedlings was pure vermiculite. The substrates with 100% of manure and the substrate with 33.33% of the mixed studied materials can be used for seedlings formation. The environment with screen can be indicated for the production of baruzeiro seedlings, since it gave vigor to the seedlings.

Production of tomato seedlings using different substrates and trays in three protected environments

The seedlings production is an essential part for vegetables production. Thus, this study aimed to evaluate the environment, the substrates and the containers in the development of tomato seedlings, cv. Santa crus Kada Gigante, in Aquidauana -MS, Brazil region, from October to November, 2008. Polystyrene trays with 72; 128 and 200 cells, filled with four substrates (soil; Plantmax®; coconut fiber and vermiculite) were tested in three protected environments (greenhouse; screened with Sombrite® and screened with Aluminet®). The experimental design was completely randomized, factorial scheme 3x4 (three trays x four substrates), with four replications, being analyzed individual variance analysis and joint analysis for the environments. The environment with screens (Sombrite® and Aluminet®), the trays with 72 cells and the vermiculite produced better results.

Citrus root distribution under water stress grown in sandy soil of central Florida

The experiment was conducted in an orchard located in University of Florida (Citrus Research and Education Center), Lake Alfred, Polk County, Florida, USA. The objective of this study was to evaluate the effects of water stress in root distribution of 'Valencia' orange tree on 'Swingle' citrumelo rootstock. Three treatments were imposed on the trees: 1) normal irrigation with microsprinklers, 2) no irrigation in winter (November through mid-March) and 3) rainfall exclusion by placing a water repelling fabric (Tyvek) under the trees. Trees in treatments 1 and 2 received normal rainfall during the winter, but treatment 3 received no rain. Normal irrigation was resumed on all treatments in mid March. Soil was collected using root auger head (0.09 m diameter and height 0.25 m) in two opposing quadrants (West and East at 3 horizontal distances from tree trunk (1, 2 and 3 m) and 4 depths (0.0-0.15; 0.15-0.30; 0.30-0.60 and 0.60-0.90 m). The results from root sampling showed that there was a significant difference in root distribution between irrigated treatment and non irrigated/non rainfall.

Experimental evaluation of the performance of a wireless sensor network in agricultural environments

The aim of this study was to perform an experimental study to evaluate the proper operation distance between the nodes of a wireless sensor network available on the market for different agricultural crops (maize, physic nut, eucalyptus). The experimental data of the network performance offers to farmers and researchers information that might be useful to the sizing and project of the wireless sensor networks in similar situations to those studied. The evaluation showed that the separation of the nodes depends on the type of culture and it is a critical factor to ensure the feasibility of using WSN. In the configuration used, sending packets every 2 seconds, the battery life was about four days. Therefore, the autonomy may be increased with a longer interval of time between sending packets.

Volume of polyethylene bags for development of papaya seedlings in protected environments

The objective of this study was to test container of polyethylene bags and protected environments on the papaya seedlings production, from May to August of 2008, in Aquidauana state of Mato Grosso do Sul (MS), Brazil. Five bags of polyethylene were used: 7.5 cm x 11.5 cm, 205.9 cm³; 8.4 cm x 10.6 cm, 238.1cm³; 10.0 cm x 16.5 cm, 525.2 cm³; 12.0 cm x 12.0 cm, 550.0 cm³ and 15.0 cm x 21.5 cm, 1539.8 cm³. These containers were placed in three protected environments: greenhouse; screened nursery with Sombrite® and screened nursery with Aluminet®. Because there is no replication of growing environment, each one was considered an experiment. For each cultivation environment, it was adopted a completely randomized design with eight replications of two plants each. Initially, data were submitted to analysis of individual variance of the container (for each cultivation environment), then performing the evaluation of the residual mean squares and the combined analysis of these environments for comparison of protected environments. The greenhouse and nursery with thermal reflector screen produced the best seedlings. The bags of 15.0 x 21.5 cm produced the best papaya seedlings. The Dickson Quality Index pointed the nursery with screen of thermal reflector as the environment that produced the most vigorous seedlings, when using the best container.

Coffee seedlings in different substrates and protected environments

The production of high-quality seedlings is a critical factor for successful implementation of a determined crop in the field. In order to evaluate the production of coffee seedlings, experiments were conducted with different substrates and in different protected environments. Treatments consisted of evaluation of the following substrates: 50% cattle manure + 50% commercial substrate, 50% cattle manure + 50% vermiculite, 50% commercial substrate + 50% vermiculite, 1/3 cattle manure + 1/3 commercial substrate + 1/3 vermiculite, 50% cattle manure + 50% sand, 1/3 sand + 1/3 cattle manure + 1/3 commercial substrate and 50% commercial substrate + 50% sand. These substrates were tested in different protected environments: agricultural greenhouse, mesh screen with 50% shading, aluminized screen with 50% shading, black screen with 30% shading, black screen with 70% shading, nursery with a buriti straw roof and full sunlight. In each environment, the experiments were conducted in a completely randomized design with five replicates of four plants each followed by joint analysis. The substrates containing 50% cattle manure associated with vermiculite or the commercial substrate may be indicated for production of coffee seedlings. Screened environments with 30, 50 and 70% shading resulted in the highest quality seedlings.

Seedlings of Acrocomia aculeata in diferent substrates and protected environments

The seedling production stage is the key to achieve uniformity in tree breeding stage. This study evaluated "bocaiúva" (Acrocomia aculeata) seedling formation, with pre-germinated seeds in different substrates and protected environments, in the University of Mato Grosso do Sul State, Aquidauana, MS. As substrates, we used 100% cattle manure (M), 100% cassava branches (CB), 100% vermiculite (V), 50% cattle manure + 50% cassava branches, 50 % cattle manure + 50% vermiculite, 50% cassava branches + 50% vermiculite and ⅓ cattle manure + ⅓ cassava branches + ⅓ vermiculite. These substrates were tested in a greenhouse covered with 150 µm low density polyethylene (LDPE) film under thermo-reflective screen with 50% shading under film; black screen with 50% shading on the sides; black monofilament screen with 50% shading set on roof and sides; and aluminized thermo- reflective screen with 50% shading set on roof and sides. The completely randomized experimental design with 5 replications of 5 plants each was adopted. Initially, data were submitted to analysis of substrate individual variance in each growing environment, then performing the waste mean square evaluation and their environment joint analysis for comparison. The best growing environment is the thermo-reflective screen compared to LDPE greenhouse and black screen set. All substrates containing manure are recommended for bocaiúva seedlings formation. The pure cassava branch is not indicated for seedling, even using chemical fertilizer.

Distribution of water in sandy soil applied by drip

The search for the use of water with high levels of efficiency has motivated the use of drip irrigation in several agricultural systems. However, for the efficiency be ensured, it is necessary that the water distribution in the soil profile must to be known in more details. As it is a highly variable process, function of the local characteristics, is essential the study of each case. The objective of this research was evaluating the water distribution in the soil profile, from drippers installed in surface and 0.15 m below the soil surface. The experiment was realized in the Technical Center of Irrigation (TCI) of the State University of Maringá - PR. The water monitoring in the soil profile was done with TDR probes installed in a box containing sandy soil, at the depths from 0.05 to 0.80 m; and 0.05 to 0.35 m of lateral spacing, at intervals of 0.05 m, totalizing 30 probes. The treatments were differentiated in relation of the installation depth of the emitters (0.0 and 0.15 m) and flow (1, 2, 4, 6, and 8 L h-1). The irrigation time was 8 hours continuous with reading of the TDR probes each 30 minutes. The results allowed concluding that the wet area with the emitter positioned on the soil surface was directly proportional to the flow increase. For the underground dripper, this area was substantially smaller and the water losses by percolation were higher, mainly to the flows higher than 4 L h-1, which provided to unacceptable water losses that should be avoided.