Effects of litter manipulation in a tropical Eucalyptus plantation on leaching of mineral nutrients, dissolved organic nitrogen and dissolved organic carbon

Although many studies have shown that soil solution chemistry can be a reliable indicator of biogeochemical cycling in forest ecosystems, the effects of litter manipulations on the fluxes of dissolved elements in gravitational soil solutions have rarely been investigated. We estimated the fluxes of NH4-N, NO3-N, K, Ca, Mg, Na, Cl, dissolved organic nitrogen (DON) and dissolved organic carbon (DOC) over the first two years after re-planting Eucalyptus trees in the coastal area of Congo. Two treatments were replicated in two blocks after clear-cutting 7-year-old stands: in treatment R, all the litter above the mineral soil was removed before planting, and in a double slash (DS) treatment, the amount of harvest residues was doubled. The soil solutions were sampled down to a depth of 4 m and the water fluxes were estimated using the Hydrus 1D model parameterized from soil moisture measurements in 4 plots. Isotopic and spectroscopic analytical techniques were used to assess the changes in dissolved organic matter (DOM) properties throughout the transfer in the soil. The first year after planting, the fluxes of NH4-N, K, Ca, Mg, Na, Cl and DOC in the topsoil of the DS treatment were 2-5 times higher than in R, which showed that litter was a major source of dissolved nutrients. Nutrient fluxes in gravitational solutions decreased sharply in the second year after planting, irrespective of the soil depth, as a result of intense nutrient uptake by Eucalyptus trees. Losses of dissolved nutrients were noticeably low in these Eucalyptus plantations despite a low cation exchange capacity, a coarse soil texture and large amounts of harvest residues left on-site at the clear cut in the DS treatment. All together, these results clarified the strong effect of litter manipulation observed on eucalypt growth in Congolese sandy soils. DOM fluxes, as well as changes in delta C-13, C:N and aromaticity of DOM throughout the soil profile showed that the organic compounds produced in the litter layer were mainly consumed by microorganisms or retained in the topsoil. Below a depth of 15 cm, most of the DOC and the DON originated from the first 2 cm of the soil and the exchanges between soil solutions and soil organic matter were low. (C) 2014 Elsevier B.V. All rights reserved.

Dissolved uranium, radium and radon evolution in the Continental Intercalaire aquifer, Algeria and Tunisia

Natural, dissolved U-238-series radionuclides (U, Ra-226, Rn-222) and activity ratios (A.R.s: U-234/U-238; Ra-228/Ra-226) in Continental Intercalaire (Cl) groundwaters and limited samples from the overlying Complexe Terminal (CT) aquifers of Algeria and Tunisia are discussed alongside core measurements for U/Th (and K) in the contexts of radiological water quality, geochemical controls in the aquifer, and water residence times. A redox barrier is characterised downgradient in the Algerian Cl for which a trend of increasing U-234/U-238 A.R.s with decreasing U-contents due to recoil-dominated U-234 solution under reducing conditions allows residence time modelling similar to 500 ka for the highest enhanced A.R. = 3.17. Geochemical modelling therefore identifies waters towards the centre of the Grand Erg Oriental basin as palaeowaters in line with reported C-14 and Cl-36 ages. A similar U-234/U-238 trend is evidenced in a few of the Tunisian CI waters. The paleoage status of these waters is affirmed by both noble gas recharge temperatures and simple modelling of dissolved, radiogenic He-4-contents both for sampled Algerian and Tunisian CI and CT waters. For the regions studied these waters therefore should be regarded as "fossil" waters and treated effectively as a non-renewable resource. (C) 2014 The Authors. Published by Elsevier Ltd.

Caracterização isotópica do CO2 dissolvido em águas subterrâneas no município de Paulínia, SP

Pós-graduação em Geociências e Meio Ambiente - IGCE

Screening the toxicity and biodegradability of petroleum hydrocarbons by a rapid colorimetric method

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Synthesis of polycationic bentonite-ionene complexes and their benzene adsorption capacity

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

The Cuticular Hydrocarbons Profiles in the Colonial Recognition of the Neotropical Eusocial Wasp, Mischocyttarus cassununga (Hymenoptera: Vespidae)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

The application of neural networks to the analysis of dissolved gases in insulating oil used in transformers

The state of insulating oils used in transformers is determined through the accomplishment of physical-chemical tests, which determine the state of the oil, as well as the chromatography test, which determines possible faults in the equipment. This article concentrate on determining, from a new methodology, a relationship among the variation of the indices obtained from the physical-chemical tests with those indices supplied by the chromatography tests.The determination of the relationship among the tests is accomplished through the application of neural networks. From the data obtained by physical-chemical tests, the network is capable to determine the relationship among the concentration of the main gases present in a certain sample, which were detected by the chromatography tests.More specifically, the proposed approach uses neural networks of perceptron type constituted of multiple layers. After the process of network training, it is possible to determine the existent relationship between the physical-chemical tests and the amount of gases present in the insulating oil.

Diagnóstico ambiental em área com vazamento de combustíveis por meio da integração de dados geofísicos e geoquímicos no município de São Manuel - SP

The contamination of the physical environment occurs as a result of the lack of planning and inadequate management of hazardous products. Due to the difficulty of the characterization and study of soil and groundwater, the contamination has been long neglected. The characterization of these areas by research techniques through direct methods such as physical and chemical analysis, are widely used in the diagnosis and monitoring. However, despite presenting quantitative results, this method is not representative in spatial terms. The purpose of this work is to bring geophysical complementation with the diagnosis, bringing the spatial element for the detection of the contamination plume. In the study area, there was a railway accident in 1999 in which three wagons fell and spilled 240,000 L of diesel onto the soil. The main objective is to assess the presence of contaminants in the residual phase and dissolved in the subsurface, using the technique of Electrical Tomography (ETR), understand the effects of natural attenuation process in the degradation of hydrocarbons and changes in electrical properties in soil and groundwater. The results allowed the definition of three distinct patterns of resistivity region with presence of dissolved phase, set in a historical chemical analyzes: low values (> 60Ω.m) associated with the presence of hydrocarbons in an advanced stage of degradation, intermediate values (260Ω.me 511Ω .m) indicative of coexistence of residual hydrocarbons and dissolved phase, and high values (> 1000Ω.m), which reveal the prevalence of residual phase with incipient degradation, possibly in high toxicity concentrations for effective action of biodegradation processes. The diagnostic of areas with potential accumulation of residual phase can subsidize the planning of remediation techniques and promote the complete decontamination of the area

Histological analysis of healing process after rat teeth replantation maintained in Resveratrol dissolved in dimethyl sufoxide (DMSO)

Tissue repair after replantation of avulsed teeth is directly related to the extent of damage to the cells of the periodontal ligament. Thus, immediate replantation is the treatment of choice for avulsed permanent teeth. To achieve more favorable prognostics, adequate storage media must be used to preserve periodontal ligament cells. A series of storage media are studied and show good results, such as saliva, milk, Hank's balanced solution (HBSS) and ViaSpan. However, recent studies were performed using news and promising storage media. Resveratrol has been extensively studied because of its antioxidant properties and its ability to prolong life of many organisms from yeast to mammals. One of its limitations is its poor solubility in aqueous vehicles. For this reason, the aim of this study was to evaluate the healing repair process after replantation of teeth of rats kept in Resveratrol using dimethyl sulfoxide (DMSO) as a vehicle. This study was approved by the Ethics Committee on Research with Animals, of the School of Dentistry of Araçatuba, Univ. Estadual Paulista, UNESP, Araçatuba, SP, Brazil. Were used 40 male rats, under general anesthesia upper right incisor were extracted and replanted. Treatments were done, dividing in four groups, of 10 animals each. In group I, the teeth were be extracted and immediately replanted into their sockets of origin (positive control). In group II, the teeth were immersed in 50 mL of resveratrol in DMSO (0.0512 g / ml) for 60 minutes. In group III teeth were kept for 60 minutes in 50 ml of DMSO. In group IV, the teeth were kept in dry for the same period (negative control). Then the teeth of animals in Groups II, III and IV were replanted in their sockets. Systemic antibiotics were administrated in all groups, and 60 days post-operative the animals were euthanized. The specimens were processed and stained in HE for histomorphological analysis. The results showed that resveratrol as storage media, was not able to improve the rep

Avaliação do processo de contaminação e remediação de água subterrânea por hidrocarbonetos

Pós-graduação em Engenharia Civil e Ambiental - FEB

Cuticular Hydrocarbons as Chemotaxonomic Characters for Nasutitermes corniger (Motschulsky) and N. ephratae (Holmgren) (Isoptera: Termitidae)

Forty-four cuticular hydrocarbon components from workers of the termites Nasutitermes corniger (Motschulsky) and N. ephratae (Holmgren) from three localities in Panama were characterized by capillary gas chromatography-electron impact mass spectrometry. Both species contain qualitatively identical homologous series of n-alkanes; 2-, 3-, 11-,13-,14-, and 15-methylalkanes; 11,15-, 12,16-, and 13,17-dimethylalkanes; and 11,15,19- and 13, 17,21-trimethylalkanes. Both species also contain a single alkene, 9-hentriacontene. The two species, however, are readily distinguished chemically by differences among the relative abundances of 11 of their major hydrocarbon components.

Relatin Dissolved Oxygen Concentration to Fish Distribution in Jarecki Lake

Abstract Water temperature and dissolved oxygen (DO) profiles were measured once every month from mid July to mid February in a relatively deep sand-pit lake in southeast Nebraska. These profiles showed depleted DO concentrations below the thermocline during summer stratification indicating areas fish will likely avoid in summer months. Colder temperatures in fall caused complete mixing of the water column allowing fish to inhabit all depths of the lake. An inverse temperature stratification occurred directly below the ice during winter months as ice cover cooled the surface water to below 4 degrees Celsius. Ice cover also blocked air – water oxygen transfer and reduced light for photosynthesizing algae. Associated with winter ice cover, DO concentrations in the hypolimnion decreased significantly, once again reducing available fish habitat. It is likely anglers will have a higher success rate catching fishing in water above 6 meters (m) (~20 feet) in a eutrophic sandpit lake during hot summer months and below ice cover in winter. Fish can utilize all depths of the lake during fall turnover and could theoretically be caught by anglers anywhere in the lake.

Polycyclic aromatic hydrocarbons and petroleum biomarkers in Sao Sebastiao Channel, Brazil: Assessment of petroleum contamination

Polycyclic aromatic hydrocarbons (PAHs) and non-aromatic hydrocarbons (NAHs), including n-alkanes, isoprenoids and petroleum biomarkers (terpanes, hopanes, steranes and diasteranes), were quantified by gas chromatography with flame ionization and mass spectrometer detectors in sediment samples collected from the Sao Sebastiao Channel (SSC), Brazil, where the largest Brazilian maritime petroleum terminal is located The concentrations of total PAHs. total n-alkanes and petroleum biomarkers ranged from below the detection limits to 370 ng g(-1,) 28 mu g g(-1), 2200 ng g(-1) (dry weight), respectively. The analysis of PAN distribution suggested combustion sources of PAHs as the main input for these compounds with smaller amount from petroleum contamination The distribution of petroleum biomarkers undoubtedly demonstrated petroleum as a source of anthropogenic contamination throughout the region. The assessment of petrogenic sources of contamination in marine sediment is more challenging if only PAH analysis were carried out, which demonstrates that more stable hydrocarbons such as petroleum biomarkers are useful for investigating potential presence of petroleum (C) 2009 Elsevier Ltd. All rights reserved.

Historical record of polycyclic aromatic hydrocarbons (PAHs) and spheroidal carbonaceous particles (SCPs) in marine sediment cores from Admiralty Bay, King George Island, Antarctica

This paper describes the first results of polycyclic aromatic hydrocarbons (PAHs) and spheroidal carbonaceous particles (SCPs) in sediment cores of Admiralty Bay, Antarctica. These markers were used to assess the local input of anthropogenic materials (particulate and organic compounds) as a result of the influence of human occupation in a sub-Antarctic region and a possible long-range atmospheric transport of combustion products from sources in South America. The highest SCPs and PAHs concentrations were observed during the last 30 years, when three research stations were built in the area and industrial activities in South America increased. The concentrations of SCPs and PAHs were much lower than those of other regions in the northern hemisphere and other reported data for the southern hemisphere. The PAH isomer ratios showed that the major sources of PAHs are fossil fuels/petroleum, biomass combustion and sewage contribution generally close to the Brazilian scientific station. (C) 2009 Elsevier Ltd. All rights reserved.

Chlorinated pesticides, polychlorinated biphenyls and polycyclic aromatic hydrocarbons in the fat tissue of seabirds from King George Island, Antarctica

Antarctic Brazilian Program (PROANTAR)