927 resultados para Receiving waters


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This paper describes a sequential injection chromatography procedure for determination of picloram in waters exploring the low backpressure of a 2.5 cm long monolithic C18 column. Separation of the analyte from the matrix was achieved in less than 60 s using a mobile phase composed by 20:80 (v v-1) acetonitrile:5.0 mmol L-1 H3PO4 and flow rate of 30 μL s-1. Detection was made at 223 nm with a 40 mm optical path length cell. The limits of detection and quantification were 33 and 137 μg L-1, respectively. The proposed method is sensitive enough to monitor the maximum concentration level for picloram in drinking water (500 μg L-1). The sampling frequency is 60 analyses per hour, consuming only 300 μL of acetonitrile per analysis. The proposed methodology was applied to spiked river water samples and no statistically significant differences were observed in comparison to a conventional HPLC-UV method.

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Horizontal and vertical distribution patterns and abundance of larval phosichthyids were investigated from oblique and depth-stratified towns off Southeastern brazilian waters, from São Tomé cape (41ºW.; 22ºS.) to São Sebastião island (45ºW.; 24ºS.). The sampling was performed during two cruises (January/2002 -summer; August/2002 -winter). Overall 538 larvae of Phosichthyidae were collected during summer and 158 in the winter. Three species, Pollichthys mauli, Vinciguerria nimbaria and Ichthyioccoccus sp. occurred in the area, but Ichthyioccoccus sp. was extremely rare represented by only one specimen, caught in the oceanic region during the summer. Geographically, larval were concentrated in the oceanic region, and vertically distributed mainly between the surface and 80 m depth in the summer and winter. Larvae were more abundant during the night, performing a diel vertical migration in the water column. The results suggest that the meandering and eddies of Brazil Current play important role on the transport and distribution patterns of larval phosichthyids over the oceanic and neritic area in the Southeastern Brazil.

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A new cheilostome bryozoan genus Marcusadorea (type species Marcusadorea jamaicensis n. sp. from the north coast of Jamaica) is described and illustrated along with a second species, Coleopora corderoi Marcus, 1949 from Southeast Brazil. A third species, Holoporella tubulosa Canu & Bassler, 1928, described from the Caribbean, but also present in Brazil, is included in this genus and redescribed. At least one Indo-West-Pacific species, ""Cosciniopsis"" efatensis Tilbrook, 2006, is a congener.

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A green and highly sensitive analytical procedure was developed for the determination of free chlorine in natural waters, based on the reaction with N,N-diethyl-p-phenylenediamine (DPD). The flow system was designed with solenoid micro-pumps in order to improve mixing conditions by pulsed flows and to minimize reagent consumption as well as waste generation. A 100-cm optical path flow cell based on a liquid core waveguide was employed to increase sensitivity. A linear response was observed within the range 10.0 to 100.0 mu g L(-1), with the detection limit, coefficient of variation and sampling rate estimated as 6.8 mu g (99.7% confidence level), 0.9% (n = 20) and 60 determinations per hour, respectively. The consumption of the most toxic reagent (DPD) was reduced 20,000-fold and 30-fold in comparison to the batch method and flow injection with continuous reagent addition, respectively. The results for natural and tap water samples agreed with those obtained by the reference batch spectrophotometric procedure at the 95% confidence level. (C) 2010 Elsevier By. All rights reserved.

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An improved procedure is proposed for determination of the pesticide carbaryl in natural waters based on double cloud point extraction. The clean up step was carried out only with Triton X-114 in alkaline medium in order to avoid the use of toxic organic solvents as well as to minimise waste generation. Cloud point preconcentration of the product of the reaction of the analyte with p-aminophenol and cetyltrimethylammonium bromide was explored to increase sensitivity and improve the detection limit. Linear response was achieved within 10 and 500 mu g L-1 and the apparent molar absorptivity was estimated as 4.6 x 105 L mol-1 cm-1. The detection limit was estimated as 7 mu g L-1 at the 99.7% confidence level and the coefficient of variation was 3.4% (n = 8). Recoveries within 91 and 99% were estimated for carbaryl spiked water samples. The results obtained for natural water samples were in agreement with those achieved by the batch of spectrophotometric procedure at the 95% confidence level. The proposed procedure is then a simple, fast, inexpensive and greener alternative for carbaryl determination.

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A flow system designed with solenoid micro-pumps is proposed for the determination of paraquat in natural waters. The procedure involves the reaction of paraquat with dehydroascorbic acid followed by spectrophotometric measurements. The proposed procedure minimizes the main drawbacks related to the standard chromatographic procedure and to flow analysis and manual methods with spectrophotometric detection based on the reaction with sodium dithionite, i.e. high solvent consumption and waste generation and low sampling rate for chromatography and high instability of the reagent in the spectrophotometric procedures. A home-made 10-cm optical-path flow cell was employed for improving sensitivity and detection limit. Linear response was observed for paraquat concentrations in the range 0.10-5.0 mg L-1. The detection limit (99.7% confidence level), sampling rate and coefficient of variation (n = 10) were estimated as 22 mu g L-1, 63 measurements per hour and 1.0%, respectively. Results of determination of paraquat in natural water samples were in agreement with those achieved by the chromatographic reference procedure at the 95% confidence level. (c) 2008 Elsevier B.V. All rights reserved.

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A multi-pumping flow system exploiting prior assay is proposed for sequential turbidimetric determination of sulphate and chloride in natural waters. Both methods are implemented in the same manifold that provides facilities for: in-line sample clean-up with a Bio-Rex 70 mini-column with fluidized beads: addition of low amounts of sulphate or chloride ions to the reaction medium for improving supersaturation; analyte precipitation with Ba(2+) or Ag(+); real-time decision on the need for next assay. The sample is initially run for chloride determination, and the analytical signal is compared with a preset value. If higher, the sample is run again, now for sulphate determination. The strategy may lead to all increased sample throughput. The proposed system is computer-controlled and presents enhanced figures of merit. About 10 samples are run per hour (about 60 measurements) and results are reproducible and Unaffected by the presence of potential interfering ions at concentration levels usually found in natural waters. Accuracy was assessed against ion chromatography. (C) 2008 Elsevier B.V. All rights reserved.

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A rapid method for classification of mineral waters is proposed. The discrimination power was evaluated by a novel combination of chemometric data analysis and qualitative multi-elemental fingerprints of mineral water samples acquired from different regions of the Brazilian territory. The classification of mineral waters was assessed using only the wavelength emission intensities obtained by inductively coupled plasma optical emission spectrometry (ICP OES), monitoring different lines of Al, B, Ba, Ca, Cl, Cu, Co, Cr, Fe, K, Mg, Mn, Na, Ni, P, Pb, S, Sb, Si, Sr, Ti, V, and Zn, and Be, Dy, Gd, In, La, Sc and Y as internal standards. Data acquisition was done under robust (RC) and non-robust (NRC) conditions. Also, the combination of signal intensities of two or more emission lines for each element were evaluated instead of the individual lines. The performance of two classification-k-nearest neighbor (kNN) and soft independent modeling of class analogy (SIMCA)-and preprocessing algorithms, autoscaling and Pareto scaling, were evaluated for the ability to differentiate between the various samples in each approach tested (combination of robust or non-robust conditions with use of individual lines or sum of the intensities of emission lines). It was shown that qualitative ICP OES fingerprinting in combination with multivariate analysis is a promising analytical tool that has potential to become a recognized procedure for rapid authenticity and adulteration testing of mineral water samples or other material whose physicochemical properties (or origin) are directly related to mineral content.

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This study aimed to compare cognitive function of cancer pain patients being given opioids during their cancer treatment (n = 14) with that of patients receiving treatment without opioids (n = 12). Correlations between cognitive function, pain intensity, and opioid dose were analyzed. Patients were assessed 3 times in a I-month period, using the Trail-Making Test, Mini-Mental State Examination, Digit Span, and Brief Cognitive Screening Battery. Opioid use was not associated with clear cognitive impairment. Patients being treated without opioids did perform better in the Digit Span Test reverse-order test (P = .029) and the clock drawing test (P = .023), but the differences arose in just I assessment in each case. Pain intensity correlated negatively with scores in the Mini-Mental State Examination (P = .001) and some Brief Cognitive Screening Battery tests (incidental recall, immediate recall, and late recall; P <= .042) in the group receiving opioids. Opioid dose did not correlate with any of the measures of cognitive performance. However, the patients with the worst performance scores were those with more severe pain. Further studies are needed to clearly distinguish between the effects of opioids versus the effects of pain.

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The interaction between poly(o-ethoxyaniline) (POEA) adsorbed onto solid substrates and humic substances (HS) and Cu(2+) ions has been investigated using UV-vis spectroscopy and atomic force microscopy (AFM). Both HS and Cu(2+) are able to dope POEA and change film morphology. This interaction was exploited in a sensor array made with nanostructured films of POEA, sulfonated lignin and HS, which could detect small concentrations of HS and Cu(2+) in water. (C) 2009 Elsevier B.V. All rights reserved.

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Background: The use of complementary and alternative medicine (CAM) to treat cancer patients has increased around the world, and its benefits have been described. These therapies represent an important theme in oncology and have been used in parallel with conventional therapies. Objective: This study aimed to assess the outcomes of using relaxation with visualization and acupuncture on the quality of life of cancer patients undergoing chemotherapy treatment and to compare these outcomes with patients who did not choose to receive the intervention. Methods: Participants chose to be in either the intervention group (IG) or control group (CG). They completed the Quality of Life Questionnaire-Core 30 at the start and end of chemotherapy. The IG was chosen by 38 patients with different types of cancer who completed weekly relaxation with visualization and acupuncture sessions, whereas the CG was composed of 37 patients who did not receive the intervention. Results: Statistically significant results evidenced an increase in global health and emotional and social functions and a decrease in fatigue and loss of appetite for the IG, and an increase in global health for the CG (P <= .05). A highly significant difference was found when comparing the post-chemotherapy scores of the Quality of Life Questionnaire-Core 30 in the global health domain between the CG and the IG (P <= .001), indicating positive outcomes of the CAM intervention. Conclusion: Adults with cancer are able to choose between involvement or not with this kind of CAM intervention. Global health could be improved by participating in this type of intervention. Implications for Practice: Choosing whether to be involved may be assisted by knowing the positive outcomes for some patients.

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Hydrochemical processes involved in the development of hydromorphic Podzols are a major concern for the upper Amazon Basin because of the extent of the areas affected by such processes and the large amounts of organic carbon and associated metals exported to the rivers. The dynamics and chemical composition of ground and surface waters were studied along an Acrisol-Podzol sequence lying in an open depression of a plateau. Water levels were monitored along the sequence over a period of 2 years by means of piezometers. Water was sampled in zero-tension lysimeters for groundwater and for surface water in the drainage network of the depression. The pH and concentrations of organic carbon and major elements (Si, Fe and Al) were determined. The contrasted changes reported for concentrations of Si, organic carbon and metals (Fe, Al) mainly reflect the dynamics of the groundwater and the weathering conditions that prevail in the soils. Iron is released by the reductive dissolution of Fe oxides, mostly in the Bg horizons of the upslope Acrisols. It moves laterally under the control of hydraulic gradients and migrates through the iron-depleted Podzols where it is exported to the river network. Aluminium is released from the dissolution of Al-bearing minerals (gibbsite and kaolinite) at the margin of the podzolic area but is immobilized as organo-Al complexes in spodic horizons. In downslope positions, the quick recharge of the groundwater and large release of organic compounds lead to acidification and a loss of metals (mainly Al), previously stored in the Podzols.

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An unusual saltwater population of the "freshwater" crocodilian, Crocodylus johnstoni, was studied in the estuary of the Limmen Bight River in Australia's Northern Territory and compared with populations in permanently freshwater habitats. Crocodiles in the river were found across a large salinity gradient, from fresh water to a salinity of 24 mg.ml-1, more than twice the body fluid concentration. Plasma osmolarity, concentrations of plasma Na+, Cl-, and K+, and exchangeable Na+ pools were all remarkably constant across the salinity spectrum and were not substantially higher or more variable than those in crocodiles from permanently freshwater habitats. Body fluid volumes did not vary; condition factor and hydration status of crocodiles were not correlated with salinity and were not different from those of crocodiles from permanently fresh water. C. johnstoni clearly has considerable powers of osmoregulation in waters of low to medium salinity. Whether this osmoregulatory competence, extends to continuously hyperosmotic environments is not known, but distributional data suggest that C. johnstoni in hyperosmotic conditions may require periodic access to hypoosmotic water. The study demonstrates a physiological capacity for colonisation of at least some estuarine waters by this normally stenohaline freshwater crocodilian.

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Street elevation.

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Street elevation.