Cilindro de gás

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Cilindro de gás

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Frascos

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kit educacional para controle e supervisão aplicado a nível

PEREIRA, J. P. ; CASTRO, B. P. S. ; VALENTIM, R. A. M. . Kit Educacional para Controle e Supervisão Aplicado a Nível. Holos, Natal, v. 2, p. 68-72, 2009

Efeitos da tilápia do Nilo (Oreochromis niloticus) e do enriquecimento por nutrientes sobre a comunidade planctônica em um lago artificial no semi-árido brasileiro

The major aim of this study was to test the hypothesis that the introduction of the Nile tilapia (Oreochromis niloticus) and the enrichment with nutrients (N and P) interact synergistically to change the structure of plankton communities, increase phytoplankton biomass and decrease water transparency of a semi-arid tropical reservoir. One field experiment was performed during five weeks in twenty enclosures (8m3) to where four treatments were randomly allocated: with tilapia addition (T), with nutrients addition (NP), with tilapia and nutrients addition (T+NP) and a control treatment with no tilapia or nutrients addition (C). A two-way repeated measures ANOVA was done to test for time (t), tilapia (T) and nutrient (NP) effects and their interaction on water transparency, total phosphorus, total nitrogen, phytoplankton and zooplankton. The results show that there was no effect of nutrient addition on these variables but significant fish effects on the biomass of total zooplankton, nauplii, rotifers, cladocerans and calanoid copepods, on the biovolume of Bacillariophyta, Zygnemaphyceae and large algae (GALD ≥ 50 μm) and on Secchi depth. In addition, we found significant interaction effects between tilapia and nutrients on Secchi depth and rotifers. Overall, tilapia decreased the biomass of most zooplankton taxa and large algae (diatoms) and decreased the water transparency while nutrient enrichment increased the biomass of zooplankton (rotifers) but only in the absence of tilapia. In conclusion, the influence of fish on the reservoir plankton community and water transparency was greater than that of nutrient loading. This finding suggests that biomanipulation should be a greater priority in the restoration of eutrophic reservoirs in tropical semi-arid regions

Avaliação da toxicidade de florações naturais e de cultura de cianobactérias: efeitos sobre Ceriodaphnia silvestri (Crustacea, Cladocera)

The incidence of toxic cyanobacterial blooms is one of the important consequences of eutrophication in aquatic ecosystems. It is a very common phenomenon in reservoirs and shrimp ponds in the State of Rio Grande do Norte (RN), Brazil. Cyanobacterias produce toxins which can affect aquatic organisms and men trough the food chain. Aiming to contribute to the studies of cyanobacterias in RN, we propose: a) to evaluate the toxicity of isolated cyanobacterias in important fresh-water environments; and b) to verify the effects of both natural and cultured blooms occurred in reservoirs for human supply and in the cladoceran Ceriodaphnia silvestrii. This study was carried out using samples of natural blooms occurred between March and October of 2004 in Gargalheiras Dam (08º L e 39º W), in July of 2004 in Armando Ribeiro Gonçalves Dam (06o S e 37o W) and in commercial shrimp ponds (Litopenaeus vannamei) located in fresh-water environments. The samples were collected with plankton net (20µm.) for identification, isolation and obtaining of phytoplanktonic biomass for liophilization and later toxicity bioassays. The toxicity of cultured samples and natural blooms was investigated through bioassays in Swiss mice. Quantification of cyanobacteria in samples was conducted following the Ütermol method, with 300mL samples fixed with lugol. The toxicity test with Ceriodaphnia silvestrii followed ABNT, 2001 recommendations, and were accomplished with natural hepatotoxic bloom s samples and cultured samples of both non-toxic and neurotoxic C. raciborskii. In this test, five newborns, aged between 6 and 24 hours, were exposed to different concentrations (0 a 800 mg.L-1) of crude cyanobacterial extracts during 24 and 48 hours. Three replicates were used per treatment. The pH, temperature and dissolved oxygen at the beginning and after 24 and 48hours from the test were measured. We estimated the CL50 through the Trimmed Spearman-Karber method. The blooms were constituted by Microcystis panniformis, M. aeruginosa, Anabaena circinalis, Cylindrospermopsis raciborskii and Planktothrix agardhii, producers of mycrocistin-LR confirmed with HPLC analysis. Samples of hepatotoxic blooms registered toxinogenic potential for C. silvestrii, with CL50-24h value of 47.48 mg.L-1 and CL5048h of 38.15 mg.L-1 for GARG samples in march/2005; CL50-24h of 113,13 mg.L-1 and CL5048h of 88,24 mg.L-1 for ARG July/2004; CL50-24h of 300.39 mg.L-1 and CL50-48h of 149.89 mg.L-1 for GARG October/2005. For cultured samples, values of CL50-24h and CL50-48h for C. raciborskii toxic strains were 228.05 and 120.28 mg.L-1, respectively. There was no mortality of C. silvestrii during the tests with non-toxic C. raciborskii strain. The toxicity test with C. silvestrii presented good sensitivity degree to cyanotoxins. The toxicity of natural hepatotoxic blooms samples (microcystins) and cultured neurotoxic saxitoxins producer samples analyzed in this study give us strong indications of that toxin s influence on the zooplanktonic community structure in tropical aquatic environments. Eleven cyanobacteria strains were isolated, representing 6 species: Anabaenopsis sp., Cylindrospermopsis raciborskii, Chroococcus sp., Microcystis panniformis, Geitlerinema unigranulatum e Planktothrix agardhii. None presented toxicity in Swiss mice. The strains were catalogued and deposited in the Laboratório de Ecologia e Toxicologia de Organismos Aquáticos (LETMA), in UFRN, and will be utilized in ecotoxicológical and ecophysiological studies, aiming to clarify the causes and control of cyanobacterial blooms in aquatic environments in RN. This state s reservoirs must receive broader attention from the authorities, considering the constant blooms occurring in waters used for human consumption

Demanda química de oxigênio, clorofila a e comunidade fitoplanctônica como indicadores da qualidade da água no Canal do Pataxó/RN

The current study examined spatial-temporal modifications and water quality through chemical and biotic indicators during both dry (January, February and November 2006) and wet seasons (March to June 2006). This study was carried out in Armando Ribeiro Gonçalves Reservoir, RN, Canal do Pataxó and after the water station treatment (WST). The physical-chemical parameters were measured in situ and inorganic nutrients, chlorophyll a and Free Oxygen Demand (FOD) were analyzed in laboratory conditions. Quali quantitative analyses of phytoplankton were carried out utilizing Sedgwick-Rafter camera. Results indicate that DQO concentrations were low. FOD concentrations in the reservoir were comparatively higher in the dry season (5.21 mgL-1; 5.64 mgL-1 e 6.05 mgL-1) in relation to the wet season (4.52 mgL-1; 4.12 mgL-1 e 4.92 mgL-1), in surface, intermediate and bottom waters, respectively. FOD values were inferior to 1.0mgL-1in both Canal do Pataxó and after WST, which is considered adequate for public use reservoirs. Although FOD concentrations were low, Armando Ribeiro Gonçalves Reservoir, Canal do Pataxó and WST were classified as euthophizied, mesotrophic ad oligotrophic, respectively, considering the Index of Trophic State Criteria. Chlorophyll a concentrations in the study reservoir were higher in the surface (199.2 µgL-1) during the wet season, whereas in Canal do Pataxó concentrations decreased from 1.56 µgL-1 to 0.028 µgL-1, and after WST values were low (0.059 µgL-1). Dominance of cianobacterias, such as Planktotrhix agardhii (dry season) and Microcystis sp (wet season) was registered in all three areas. In the reservoir and Canal do Pataxó, density of cianobacterias, such as P. agardhii and Microcistys sp., was superior to the values allowed by the Health ministry (HM). However, after WST, density values of cianobacteria were inferior to values established by the HM

Potencialidades de cultivo de macroalgas no litoral do Rio Grande do Norte (NE, Brasil): uma perspectiva de integração de dados ambientais em sistemas de informação geográfica (SIG)

Since centuries ago, the Asians use seaweed as an important source of feeding and are their greatest world-wide consumers. The migration of these peoples for other countries, made the demand for seaweed to increase. This increasing demand prompted an industry with annual values of around US$ 6 billion. The algal biomass used for the industry is collected in natural reservoirs or cultivated. The market necessity for products of the seaweed base promotes an unsustainable exploration of the natural banks, compromising its associated biological balance. In this context, seaweed culture appears as a viable alternative to prevent the depletion of these natural supplies. Geographic Information Systems (GIS) provide space and produce information that can facilitate the evaluation of important physical and socio-economic characteristics for the planning of seaweed culture. This objective of this study is to identify potential coastal areas for seaweed culture in the state of Rio Grande do Norte, from the integration of social-environmental data in the SIG. In order to achieve this objective, a geo-referred database composed of geographical maps, nautical maps and orbital digital images was assembled; and a bank of attributes including physical and oceanographical variables (winds, chains, bathymetry, operational distance from the culture) and social and environmental factors (main income, experience with seaweed harvesting, demographic density, proximity of the sheltered coast and distance of the banks) was produced. In the modeling of the data, the integration of the space database with the bank of attributes for the attainment of the map of potentiality of seaweed culture was carried out. Of a total of 2,011 ha analyzed by the GIS for the culture of seaweed, around 34% or 682 ha were indicated as high potential, 55% or 1,101 ha as medium potential, and 11% or 228 ha as low potential. The good indices of potentiality obtained in the localities studied demonstrate that there are adequate conditions for the installation of seaweed culture in the state of Rio Grande do Norte

Estudo sobre a participação de rodedores na cadeia de transmissão de Leishmania infantum (Protozoa: Trypanosomatidae) no Rio Grande do Norte

American visceral leishmaniasis is a zoonosis caused by Leishmania infantum and transmitted by the bite of the sand flies Lutzomia longipalpis.The main domestic reservoir is the dog, while foxes and opposums are the known wild reservoirs. However, identification of natural infections with L. infantum in rodents appears for need of investigating the participation of these rodents how source of infection of the parasite. In the present work the Leishmania infantum infection was investigated in rodents captured in Rio Grande do Norte, aiming at to offer subsidies to the understanding of the epidemic chains of LVA in the State. Thirteen Galea spixii were distributed in four groups, being G1 the group control with four animals and the others, G2, G3 and G4, with three animals each. Those animals were intraperitoneally inoculated with 107 promastigotas of L. infantum and accompanied for, respectively, 30, 90 and 180 days. Weekly the animals were monitored as for the corporal weight and rectal temperature. At the end of each stipulated period the animals were killed. Blood were used for determination of the parameters biochemical and haematological, PCR, ELISA, microscopic examination and cultivation in NNN medium. Liver, spleen and lymph node were used in Giemsa-stained impression and cultivation in NNN medium. Liver and spleen fragments were still used in PCR and histopathological, respectively. At the same time 79 rodents of the species Rattus rattus, Bolomys lasiurus, Oligoryzomys nigripis, Oryzomys subflavus and Trichomys apereoides were captured in the Municipal districts of Brejinho, Campo Grande, Coronel Ezequiel, Passa e Fica and Vázea for identification of natural infection with L. infantum. Evidence of infection was checked by direct examination of Giemsa-stained impression of liver, spleen and blood and culture of these tissues in NNN medium. Antibodies were researched by ELISA. They were not found differences among the weigh corporal final, rectal temperature and biochemical and haematological parameters of the Galea spixii controls and infected. The rectal temperature of the animals varied from 36OC to 40OC. For the first time values of the haematocrit (33,6% to 42,8%), hemoglobin (10,2 to 14,5g/dl), erythrocyts number (4,67x106 to 6,90x106/mm3), total leukocytes (0,9x103 to 9,2x103/mm3), platelets (49x103 to 509x103/mm3) total proteins (1,56 to 6,06 g/dl), albumin (1,34 to 3,05 g/dl) and globulins (0,20 to 3,01 g/dl) of the Galea spixii were determined. The lymphocytes were the most abundant leucocytes. Infection for L. infantum was diagnosed in two animals euthanasied 180 days after the infection. In one of the animals was also identified antibodies anti-Leishmania. The parasite was not found in none of the five other species of rodents captured. Galea spixii are resistant to the infection for L. infantum and they are not good models for the study for visceral leishmaniose, although they can act as infection sources. More studies are necessary to determine the paper of the rodents in the epidemic chain of transmission of the visceral leishmaniose in the State of Rio Grande do Norte

Metagenômica comparativa de solo de regiões de mata atlântica e caatinga do estado do Rio Grande do Norte - Brasil

The microorganisms play very important roles in maintaining ecosystems, which explains the enormous interest in understanding the relationship between these organisms as well as between them and the environment. It is estimated that the total number of prokaryotic cells on Earth is between 4 and 6 x 1030, constituting an enormous biological and genetic pool to be explored. Although currently only 1% of all this wealth can be cultivated by standard laboratory techniques, metagenomic tools allow access to the genomic potential of environmental samples in a independent culture manner, and in combination with third generation sequencing technologies, the samples coverage become even greater. Soils, in particular, are the major reservoirs of this diversity, and many important environments around us, as the Brazilian biomes Caatinga and Atlantic Forest, are poorly studied. Thus, the genetic material from environmental soil samples of Caatinga and Atlantic Forest biomes were extracted by direct techniques, pyrosequenced, and the sequences generated were analyzed by bioinformatics programs (MEGAN MG-RAST and WEBCarma). Taxonomic comparative profiles of the samples showed that the phyla Proteobacteria, Actinobacteria, Acidobacteria and Planctomycetes were the most representative. In addition, fungi of the phylum Ascomycota were identified predominantly in the soil sample from the Atlantic Forest. Metabolic profiles showed that despite the existence of environmental differences, sequences from both samples were similarly placed in the various functional subsystems, indicating no specific habitat functions. This work, a pioneer in taxonomic and metabolic comparative analysis of soil samples from Brazilian biomes, contributes to the knowledge of these complex environmental systems, so far little explored

Estudo clínico-laboratorial e histopatológico de cães naturalmente infectados por Leishmania chagasi com diferentes graus de manifestação física

Canine Visceral Leishmania (CVL) is an important zoonotic disease that has a world wide distribution and has a large impact on public health on the American Continent, especially in Brazil, where the nature of endemic diseases in humans affects a large part of the nation. The influence of the prevalence of CVL in the increased rate of human cases in endemic areas and in the unleashing of epidemic outbreaks shows the need for a more profound understanding, that would generate significant advances in the current measures used to control the reservoirs of sickness that are practiced by the Programa Nacional de Vigilância e Controle da Leishmaniose Visceral. The present work describes and compares the clinical-laboratorial and histopathological findings of twenty-three dogs that were naturally infected by Leishmania chagasi, from endemic areas in metropolitan Natal, Rio Grande do Norte, Brazil. These animals, that were selected and given physical and serological exams (IFI and ELISA rK-39), were classified according to the degree of clinical severity and had blood samples drawn (whole blood and serum) for a complete hemogram and a coagulogram to be done as well as biochemical tests for kidney and liver function. The confirmation of infection by L. chagasi was done after the euthanasia of the animals, through the direct demonstration of the parasite in the impression of the spleen and liver crowned with GIEMSA and through a cultivation by means of NNN/Schneider. According to the clinical evaluation, the animals were classified as asymptomatic (7), oligosymptomatic (7) and polysymptomatic (9). Among the animals that were chosen to be autopsied, there were 2 asymptomatic, 3 oligosymptomatic and 3 polysymptomatic, for the purpose of studying their histopathology, having collected fragments of the spleen, liver, kidneys and skin and were fixed in 10% tamponed formol. The comparison between the average parameters of the clinical-laboratory tested animals in the groups was done through the Student t test (a<0.05). The main clinical signals observed were lymphadenomegaly, alopecy, dermatitis, exfoliation, cutaneous ulcers, onicogriphosis and emaciation. The main clinical-laboratorial alterations established, mainly in the polysymptomatic group, were anemia, hyperproteinemia, hyperglobulinemia, alterations in the albumin/globulin ratio and increased ALT activity. Renal alterations were not verified (urea and creatinine levels were normal). Thrombocytopenia was observed in three clinical groups. However, the other indicators of coagulation function (TAP and TTPA) did not have abnormal variations. There were inflammatory infiltrations and leishmania amastigotes in the skin of polysymptomatic dogs, however, they were not found in the skin of asymptomatic animals. Hypertrophy and hyperplasia of the phagocyte mononuclear system, leishmania amastigote parasites were found in the macrophages, extramedullary hematopoiesis and degenerative alterations were detected in the spleen and liver of 8 of the animals submitted to histopathological exams. In accord with these results, it was demonstrated that the expected alterations in the hematological and biochemical parameters in function of their viscerotropic nature of CVL are mainly observed in the more advanced stages of the disease. The absence of inflammatory infiltration and parasite load in the skin suggest that infected animals without symptoms may have an importance irrelevant to the infectiousness of the vector

Efetividade da doxiciclina na profilaxia contra letptospirose

Leptospirosis is a worldwide zoonosis of considerable medical and economical importance that affects humans in both urban and rural contexts, as well as domestic animals and wild fauna. Leptospira interrogans is the causative agent and is transmitted to humans by indirect contact with contaminated soil or water. The clinical syndromes include sub clinical infection, self-limited anicteric febrile illness, and severe and potentially fatal illness, known as Weil´s syndrome. In developed countries, leptospirosis is related to occupational or recreational activities while in developing countries, outbreaks occur during floods. In those regions, traditional strategies to prevent the transmission are difficulties to be implemented because of costs and lack of community acceptance. In addition, no efficient vaccine is available for human use. Several studies have suggested that chemoprophylaxis with doxycycline pre and post-exposure may be effective to prevent leptospirosis. Leptospirosis has been reported in rural areas of the State of Rio Grande do Norte, Brazil since 1985 in rice farmers who present the anicteric illness. The disease cause great social and economics impact. The study was conducted in São Miguel where an epidemic of leptospirosis in rice farmers was reported. The main objective was to determine the efficacy of doxycycline in preventing Leptospira exposure. A taxa de soroprevalência de leptospirose na população estudada antes e após a colheita foi de 14,2% (n=22) e de 16.6% (n=27) respectivamente. Anti-Leptospira serology was determined for 61 subjects in two instances, pre and post-exposure to potential contaminated water. There was an increased risk of 29.0 per cent in acquiring infection for individuals that did not use doxycycline. In addition, an increased risk of 30.0 % observed in farmers who did not use protection when exposed to Leptospira. The adhesion to preventive chemoprophylaxis was 55.7%. Therefore doxycycline, under specific circunstances appears to be an effective alternative to protect against leptosprirosis infection. A large sample composed of individuals to adhere to preventive therapy is needed to define time, dosage and length of use of doxycycline in this area

Influência da vermiculita expandida na resistência à compressão e reologia de pastas cimentantes de poços de petróleo

Several problems related to the loss of hydraulic seal in oilwells, causing gas migration and/or contamination of the production zone by water, have been reported. The loss of the hydraulic seal is a consequence of cracks which can be occasioned either by the invasion of gas during the wait on cement or by the expansion of the casing causing the fracture of the cement sheath. In case of the pressure of the formation is higher than the pressure in the annulus, gas can migrate into the slurry and form microannulus, which are channels where gas migrates after the cement is set. Cracks can be also occasioned by the fracture of the cement sheath when it does not withstand the thermal and dynamic loads. In reservoirs where the oil is heavy, steam water injection operation is required in order to get the oil flowing. This operation increases the temperature of the casing, and then it expands and causes the fracture of the cement sheath in the annulus. When the failures on the cement are detected, remedial cementing is required, which raise costs caused by the interventions. Once the use of cement in the construction civil sector is older than its use in the petroleum sector, it is common to bring technologies and solutions from the civil construction and apply them on the petroleum area. In this context, vermiculite, a mineral-clay widely encountered in Brazil, has been used, on its exfoliated form, in the civil construction, especially on the manufacture of lights and fireproof concretes with excellent thermal and acoustical properties. It has already been reported in scientific journals, studies of the addition of exfoliated vermiculite in Portland cements revealing good properties related to oilwell cementing operations. Thus, this study aimed to study the rheological behavior, thickening time, stability and compressive strength of the slurries made of Portland cement and exfoliated vermiculite in 5 different compositions, at room temperature and heated. The results showed that the compressive strength decreased with the addition of exfoliated vermiculite, however the values are still allowed for oiwell cementing operations. The thickening time of the slurry with no exfoliated vermiculite was 120 min and the thickening time of the slurry with 12 % of exfoliated vermiculite was 98 min. The stability and the rheological behavior of the slurries revealed that the exfoliated vermiculite absorbed water and therefore increased the viscosity of the slurries, even though increasing the factor cement-water. The stability experiment carried out at 133 ºF showed that, there was neither sedimentation nor reduction of the volume of the cement for the slurry with 12 % of exfoliated vermiculite. Thus, the addition of exfoliated vermiculite accelerates the set time of the cement and gives it a small shrinkage during the wait on cement, which are important to prevent gas migration

Análise do comportamento reológico de pastas de cimento contendo resíduos de pneu para poços de petróleo

The low tenacity presented by the Portland cement pastes used in the oil wells cementation has been motivating several researches with attention focused on alternative materials. Additives have been developed to generate flexible pastes with mechanical resistance capable to support the expansions and retractions of the metallic covering of the wells that submit to the steam injection, technique very used to increase the recovery factor in oil reservoirs with high viscosity. A fresh paste with inadequate rheological behavior may commit the cementation process seriously, involving flaws that affect the performance of the paste substantially in the hardened state. This work proposes the elaboration and the rheological analysis of Portland cement pastes with addition of residues of rubber tire in several proportions, with the aim of minimizing the damages provoked in the hem cementing of these wells. By thermogravimetric analysis, the particles of eraser that go by the sieve of 0,5mm (35 mesh) opening and treated superficially with NaOH solution of 1 mol/L presented appropriate thermal resistance for wells that submit to thermal cyclic. The evaluation of the study based on the results of the rheological analysis of the pastes, complemented by the mechanical analysis, thickening, stability, tenor of free water and filtrate loss, being used as parameter a paste reference, without rubber addition. The results showed satisfactory rheology, passive of few corrections; considerable loss of mechanical resistance (traction and compression), compensated by earnings of tenacity, however with established limits for its application in oil wells; satisfactory stability, free water and thickening time

Avaliação da influência do nacl em pastas de cimento portland para cimentação de poços de petróleo em zonas evaporíticas

One of the major current challenges for oilwell companies is the extraction of oil from evaporitic zones, also known as pre-salt basins. Deep reservoirs are found under thick salt layers formed from the evaporation of sea water. Salt layers seal the flow of oil from underneath rock formations, which store hydrocarbons and increase the probability of success in oil and gas exploration. Oilwells are cemented using Portland-based slurries to promote mechanical stability and zonal isolation. For pre-salt oilwells, NaCl must be added to saturate the cement slurries, however, the presence of salt in the composition of slurries affects their overall behavior. Therefore, the objective of the present study was to evaluate the effect of the addition of 5 to 25% NaCl on selected properties of Portland-based slurries. A series of tests were carried out to assess the rheological behavior, thickening time, free water and ultrassonic compressive strength. In addition, the slurries were also characterized by thermal analysis, X ray diffraction and scanning electron microscopy. The results showed that the addition of NaCl affected the thickening time of the slurries. NaCl contents up to 10% shortened the thickening time of the slurries. On the other hand, concentrations in excess of 20% not only extended the thickening time, but also reduced the strength of hardened slurries. The addition of NaCl resulted in the formation of a different crystalline phase called Friedel´s salt, where free chlorine is bonded to tricalcium aluminate