The statistical properties of tropical ice clouds generated by the West-African and Australian monsoons from ground-based radar-lidar observations

In the present paper we characterize the statistical properties of non-precipitating tropical ice clouds (deep ice anvils resulting from deep convection and cirrus clouds) over Niamey, Niger, West Africa, and Darwin, northern Australia, using ground-based radar–lidar observations from the Atmospheric Radiation Measurement (ARM) programme. The ice cloud properties analysed in this paper are the frequency of ice cloud occurrence, cloud fraction, the morphological properties (cloud-top height, base height, and thickness), the microphysical and radiative properties (ice water content, visible extinction, effective radius, terminal fall speed, and concentration), and the internal cloud dynamics (in-cloud vertical air velocity). The main highlight of the paper is that it characterizes for the first time the probability density functions of the tropical ice cloud properties, their vertical variability and their diurnal variability at the same time. This is particularly important over West Africa, since the ARM deployment in Niamey provides the first vertically resolved observations of non-precipitating ice clouds in this crucial area in terms of redistribution of water and energy in the troposphere. The comparison between the two sites also provides an additional observational basis for the evaluation of the parametrization of clouds in large-scale models, which should be able to reproduce both the statistical properties at each site and the differences between the two sites. The frequency of ice cloud occurrence is found to be much larger over Darwin when compared to Niamey, and with a much larger diurnal variability, which is well correlated with the diurnal cycle of deep convective activity. The diurnal cycle of the ice cloud occurrence over Niamey is also much less correlated with that of deep convective activity than over Darwin, probably owing to the fact that Niamey is further away from the deep convective sources of the region. The frequency distributions of cloud fraction are strongly bimodal and broadly similar over the two sites, with a predominance of clouds characterized either by a very small cloud fraction (less than 0.3) or a very large cloud fraction (larger than 0.9). The ice clouds over Darwin are also much thicker (by 1 km or more statistically) and are characterized by a much larger diurnal variability than ice clouds over Niamey. Ice clouds over Niamey are also characterized by smaller particle sizes and fall speeds but in much larger concentrations, thereby carrying more ice water and producing more visible extinction than the ice clouds over Darwin. It is also found that there is a much larger occurrence of downward in-cloud air motions less than 1 m s−1 over Darwin, which together with the larger fall speeds retrieved over Darwin indicates that the life cycle of ice clouds is probably shorter over Darwin than over Niamey.

Mozzarella-type curd made from buffalo, cows’ and ultrafiltered cows’ milk. 2. Physicochemical properties, curd yield and quality, casein fractions & micelles size

Buffalo milk contains (40–60 %) more protein, fat and calcium than cows’ milk. These constituents were enhanced by ultrafiltration (UF) of cows’ milk to give a product with similar levels to those found in the buffalo milk. Mozzarella-type curd was made from buffalo, cows’ and UF cows’ milk to compare the overall curd yield and quality. The curd yield on both dry and wet weight basis, curd moisture content and overall curd fat retention were found to be higher in the UF cows’ milk than for either the buffalo or the cows’ milk preparations. The minimum whey fat losses occurred in the UF cows’ curd when compared to the cows’ and the buffalo curd. The whey protein losses were found to be higher in the UF cows’ curd than those for the buffalo and the cows’ curds. The total mineral content of the curd was also higher in the UF cows’ milk than that found in either the buffalo or the cows’ milk. SEM micrographs showed that casein micelles sizes were different in the two different types of milk. Casein micelles were also observed to be deformed in the UF cows’ milk samples. UF cows’ milk contained higher amounts of both the αs1- and αs2-casein moieties than either the buffalo or the cows’ milk. Buffalo milk was found to contain a higher concentration of β-casein than either the UF cows’ or untreated cows’ milk samples. Gel strength was found to be higher in the resultant buffalo curd than for curds made from either native cows’ milk or those made from UF cows’ milk. The mineral distribution was also different in the three different types of bovine milk, measured by energy-dispersive X-ray (EDX) analysis. Differences in the curd quality observed between the buffalo and the cows’ milk appear to result from the differences in casein composition and overall micelle structure, rather than casein concentration alone.

Impact of vegetation and preferential source areas on global dust aerosol: results from a model study

[1] We present a model of the dust cycle that successfully predicts dust emissions as determined by land surface properties, monthly vegetation and snow cover, and 6-hourly surface wind speeds for the years 1982–1993. The model takes account of the role of dry lake beds as preferential source areas for dust emission. The occurrence of these preferential sources is determined by a water routing and storage model. The dust source scheme also explicitly takes into account the role of vegetation type as well as monthly vegetation cover. Dust transport is computed using assimilated winds for the years 1987–1990. Deposition of dust occurs through dry and wet deposition, where subcloud scavenging is calculated using assimilated precipitation fields. Comparison of simulated patterns of atmospheric dust loading with the Total Ozone Mapping Spectrometer satellite absorbing aerosol index shows that the model produces realistic results from daily to interannual timescales. The magnitude of dust deposition agrees well with sediment flux data from marine sites. Emission of submicron dust from preferential source areas are required for the computation of a realistic dust optical thickness. Sensitivity studies show that Asian dust source strengths are particularly sensitive to the seasonality of vegetation cover.

Antimicrobial resistance of heterotrophic marine bacteria isolated from seawater and sands of recreational beaches with different organic pollution levels in southeastern Brazil: evidences of resistance dissemination

Antimicrobial resistance of marine heterotrophic bacteria to different antimicrobials agents were evaluated in seawater, dry and wet sands from three marine recreational beaches with different pollution levels. In all studied beaches, the greatest frequencies of resistance were found in relation to penicillin. on Gonzaguinha, the most polluted beach, 72.3% of all isolated strains showed simple resistance, whilst 8.33% had multiple resistance. The values found on Ilha Porchat beach, were 70.8% and 6.9% for simple and multiple resistances, respectively. on GuaraA(0), the less polluted beach, only 35.3% of isolated strains had simple resistance. Multiple resistance was not observed. While samples from Gonzaguinha and Ilha Porchat beach showed isolated strains resistant to seven and six different antimicrobial agents, respectively, samples from GuaraA(0) beach were resistant only to penicillin and erytromicin. The positive correlations obtained between the degree of seawater contamination and frequency and variability of bacterial resistance indicate that polluted marine recreational waters and sands are sources of resistant bacteria contributing thus, to the dissemination of bacterial resistance.

Influence of management on plankton community of fishponds during the dry and rainy seasons

Aim: The present investigation aims at evaluating attention to the occurrence and abundance of planktonic communities in fishponds and their relationships to the management employed; Methods: Seven fishponds (V1-V7) fertilized with different treatments were analyzed by monthly sampling, taken between July and December/07, during both dry and rainy seasons; Results: Euglenophyceae and Chlorophyceae were most representative during the studied period. In the fishpond with organic fertilizer Cyanobacteria was more than 65 and 90% of total phytoplankton abundance in September and August, mainly represented by Microcystis sp. (14,595 and 22,500 ind.L-1, respectively). An inverse relationship occurred between Copepoda and Cladocera, and Copepoda and Rotifera were present in all fishponds during the both seasons. Diversity (H') and species richness was low and equitability indices generally showed the highest values for zooplankton. The lowest values were observed for phytoplankton during the rainy season; Conclusions: The use of organic fertilizer and the random emptying of the fishponds affected directly and species diversity and richness, with dominance of Cyanobacteria emphasizing the need to adopt a management technique to increase fishponds productivity and consequently, fish production.

Physical, chemical and microbiological aspects during the dry and rainy seasons in a pond covered by macrophyte used in aquaculture water supply

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

Distribution of contagious and environmental mastitis agents isolated from milk samples collected from clinically health buffalo cows between brazilian dry and rainy seasons of the year

The present study was performed to evaluate the microbiological characteristics of clinically health quarters submitted to milking and also to observe the distribution of contagious and environmental agents between brazilian dry and rainy seasons of the year. During nine months 734 quarters from 37 buffalo cows were submitted monthly to udder inspection, palpation and strip cup test before milking. 734 asseptic milk samples were inoculated in 10% ovine blood agar and in MacConkey agar media, then incubated for 72 hours at 37 C. Among the 580 isolated microrganisms, 182 (31,38%) were recovered from samples collected during the rainy season and 398 (68,62%) from the dry season. In the rainy period the most prevalent agents were: bacteria from the genus Corynebacterium sp (53,30%), Staphylococcus sp (19,78%) and Rhodococcus equi (13,74%). In the dry period, the commonest ones were: Corynebacterium sp (44,97%), Staphylococcus sp (18,84%) and Micrococcus sp (9,55%). The results demonstrated that the methods used to select health quarters in brazilian dairy buffalo farms allow the transmission of contagious bacteria during both seasons of the year, maintaining agents known to cause mainly subclinical inflammatory reactions that compromise cronically the physiology and production of the mammary gland.

Activity and habitat use of two species of stingrays (Myliobatiformes: Potamotrygonidae) in the upper Paraná River basin, Southeastern Brazil

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Structure and feeding of a stream fish assemblage in southeastern Brazil: evidence of low seasonal influences

Aim: The present study was developed in a deforested stream located in a region that exhibits marked seasonality with the purpose to investigate whether ecological descriptors of the quantitative structure (i.e., composition, abundance, biomass, species richness, diversity) and feeding of fishes do change between the dry and wet periods. Methods: Sampling was conducted bimonthly from April 2004 to February 2005 by using a standardized effort with electrofishing equipment and environmental variables measurements. Results: We collected 713 fishes belonging to 23 species. The most abundant species were Gymnotus carapo (24.0%) and Poecilia reticulata (23.8%). Species richness, abundance, and biomass showed to be higher in the wet period, but these differences were not significant and did not influence the multivariate pattern of the assemblage (ANOSIM, R = 0.148). Nevertheless, average dissimilarity between community structure in the dry and wet periods was 52.7%, mainly due to the differential contribution of P. reticulata, notably more abundant in the wet season, under quasi-hypoxic water conditions. Examination of 333 gastric contents of 12 species evidenced that food variety was higher in the dry period. of these species, 67% (Astyanax altiparanae, Astyanax fasciatus, Geophagus brasiliensis, Gymnotus carapo, Hypostomus ancistroides, Phalloceros harpagos, Poecilia reticulata, and Rhamdia quelen) kept the diet throughout the year, being classified in the same trophic groups in both periods, and detritus was the most important item for half of them, followed by aquatic insects. Overall, no significant differences in the community's diet between periods were registered (ANOSIM, R = [long dash]0.04). Conclusions: This relative constancy suggests a quite regular availability of resources (mainly shelters in submerged marginal grasses and detritus) along the year.

Effect of conditioning methods on the microtensile bond strength of phosphate monomer-based cement on zirconia ceramic in dry and aged conditions

The objective of this study was to evaluate the durability of bond strength between a resin cement and aluminous ceramic submitted to various surface conditioning methods. Twenty-four blocks (5 X 5 X 4 mm 3) of a glass-in filtrated zirconia-alumina ceramic (inCeram Zirconia Classic) were randomly divided into three surface treatment groups: ST1-Air-abrasion with 110-mu m Al2O3 particles + silanization; ST2-Laboratory tribochemical silica coating method (110-mu m Al2O3, ilO-PM Silica) (Rocatec) + silanization; ST3-Chairside tribochemical silica coating method (30-mu m SiOx) (CoJet) + silanization. Each treated ceramic block was placed in its silicone mold with the treated surface exposed. The resin cement (Panavia F) was prepared and injected into the mold over the treated surface. Specimens were sectioned to achieve nontrimmed bar specimens (14 sp/block) that were randomly divided into two conditions: (a) Dry-microtensile test after sectioning; (b) Thermocycling (TC)-(6,000X, 5-55 degrees C) and water storage (150 days). Thus, six experimental groups were obtained (11 = 50): Gr1-ST1 + dry; Gr2-ST1 + TC. Gr3-ST2 + dry; Gr4-ST2 + TC; Gr5-ST3 + dry; Gr6ST3 + TC. After microtensile testing, the failure types were noted. ST2 (25.1 +/- 11) and ST3 (24.1 +/- 7.4) presented statistically higher bond strength (MPa) than that of STI (17.5 +/- 8) regardless of aging conditions (p < 0.0001). While Gr2 revealed the lowest results (13.3 +/- 6.4), the other groups (21.7 +/- 7.4-25. 9 +/- 9.1) showed statistically no significant differences (two-way ANOVA and Tukey's test, a 0.05). The majority of the failures were mixed (82%) followed by adhesive failures (18%). Gr2 presented significantly higher incidence of ADHESIVE failures (54%) than those of other groups (p = 0.0001). Both laboratory and chairside silica coating plus silanization showed durable bond strength. After aging, airabrasion with 110-mu m Al2O3 + silanization showed the largest decrease indicating that aging is fundamental for bond strength testing for acid-resistant Arconia ceramics in order to estimate their long-term performance in the mouth. (c) 2007 Wiley Periodicals, Inc.

Effects of Surface Hydration and Application Method on the Bond Strength of Self-Etching Adhesives to Dentin

The effect of application methods and dentin hydration on the bond strength of three self-etching adhesives (SEA) were evaluated; 195 extracted bovine incisors were used. The buccal surface was ground in order to expose the dentin, which remained 2-mm minimum thickness, measured by a thickness meter through an opening on the lingual surface. Adper Single Bond 2 (TM) was used for the control group. The SEA were applied following two modes of application: passive or active and two hydration states of the dentin surface-dry and wet. After light-curing, composite buildups were made using Grandio (TM) composite. The specimens were sectioned and tested with a microtensile bond strength test. The application method and the hydration state resulted in statistical differences (p = 0.000) making the values of active application for mu TBS to dentin higher than passive application. The wet surfaces showed higher mu TBS to dentin ratios than dry surfaces. There were no statistical differences in mu TBS among the SEA tested but there were differences regarding to control group.

Effects of daily changes in environmental factors on the abundance and richness of Odonata

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Different responses in bulk density and saturated hydraulic conductivity to soil deformation by logging machinery on a Ferralsol under native forest

Ferralsols have high structural stability, although structural degradation has been observed to result from forest to tillage or pasture conversion. An experimental series of forest skidder passes in an east Amazonian natural forest was performed for testing the effects of mechanical stress during selective logging operations on a clay-rich Ferralsol under both dry and wet soil conditions. Distinct ruts formed up to 25 cm depth only under wet conditions. After nine passes the initially very low surface bulk density of between 0.69 and 0.80 g cm(-3) increased to 1.05 g cm(-3) in the wet soil and 0.92 g cm(-3) in the dry soil. Saturated hydraulic conductivities, initially > 250 mm h(-1), declined to a minimum of around 10 mm h(-1) in the wet soil after the first pass, and in the dry soil more gradually after nine passes. The contrasting response of bulk density and saturated hydraulic conductivity is explained by exposure of subsoil material at the base of the ruts where macrostructure rapidly deteriorated under wet conditions. We attribute the resultant moderately high hydraulic conductivities to the formation of stable microaggregates with fine sand to coarse silt textures. We conclude that the topsoil macrostructure of Ferralsols is subject to similar deterioration to that of Luvisols in temperate zones. The stable microstructure prevents marked compaction and decrease in hydraulic conductivity under wetter and more plastic soil conditions. However, typical tropical storms may regularly exceed the infiltration capacity of the deformed soils. In the deeper ruts water may concentrate and cause surface run-off, even in gently sloping areas. To avoid soil erosion, logging operations in sloping areas should therefore be restricted to dry soil conditions when rut formation is minimal.

Precipitation chemistry and wet deposition in Kruger National Park, South Africa

The chemical composition, as well as the sources contributing to rainwater chemistry have been determined at Skukuza, in the Kruger National Park, South Africa. Major inorganic and organic ions were determined in 93 rainwater samples collected using an automated wet-only sampler from July 1999 to June 2002. The results indicate that the rain is acidic and the averaged precipitation pH was 4.72. This acidity results from a mixture of mineral acids (82%, of which 50% is H2SO4) and organic acids (18%). Most of the H2SO4 component can be attributed to the emissions of sulphur dioxide from the industrial region on the Highveld. The wet deposition of S and N is 5.9 kgS.ha(-1).yr(-1) and 2.8 kgN.ha(-1).yr(-1), respectively. The N deposition was mainly in the form of NH4+. Terrigenous, sea salt component, nitrogenous and anthropogenic pollutants have been identified as potential sources of chemical components in rainwater. The results are compared to observations from other African regions.

Microtensile bond strength of a resin cement to feldpathic ceramic after different etching and silanization regimens in dry and aged conditions

Objectives. This study evaluated the durability of bond strength between resin cement and a feldspathic ceramic submitted to different etching regimens with and without silane coupling agent application.Methods. Thirty-two blocks (6.4 mm x 6.4 mm x 4.8 mm) were fabricated using a microparticulate feldspathic ceramic (Vita VM7), ultrasonically cleaned with water for 5 min and randomly divided into four groups, according to the type of etching agent and silanization method: method 1, etching with 10% hydrofluoric (HF) acid gel for I min + silanization; method 2, HF only; method 3, etching with 1.23% acidulated phosphate fluoride (APF) for 5 min + silanization; method 4, APF only. Conditioned blocks were positioned in their individual silicone molds and resin cement (Panavia F) was applied on the treated surfaces. Specimens were stored in distilled water (37 degrees C) for 24 h prior to sectioning. After sectioning the ceramic-cement blocks in x- and Y-axis with a bonded area of approximately 0.6 mm(2), the microsticks of each block were randomly divided into two storage conditions: Dry, immediate testing; TC, thermal cycling (12,000 times) + water storage for 150 d, yielding to eight experimental groups. Microtensile bond strength tests were performed in universal testing machine (cross-head speed: 1 mm/min) and failure types were noted. Data obtained (MPa) were analyzed with three-way ANOVA and Tukey's test (alpha = 0.05).Results. Significant influence of the use of silane (p < 0.0001), storage conditions (p = 0.0013) and surface treatment were observed (p = 0.0014). The highest bond strengths were achieved in both dry and thermocycled conditions when the ceramics were etched with HF acid gel and silanized (17.4 +/- 5.8 and 17.4 +/- 4.8 MPa, respectively). Silanization after HF acid gel and APT treatment increased the results dramatically (14.5 +/- 4.2-17.4 +/- 4.8 MPa) compared to non-silanized groups (2.6 +/- 0.8-8.9 +/- 3.1 MPa) where the failure type was exclusively (100%) adhesive between the cement and the ceramic.Significance. Silanization of the feldspathic ceramic surface after APF or HF acid etching increased the microtensile bond strength results significantly, with the latter providing higher results. Long-term thermocycling and water storage did not decrease the results in silanized groups. (C) 2006 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.