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Certified reference material (CRM) for natural (40K,210Pb,210Po,226Ra,228Ra,228Th,230Th,232Th,234U,235U, and238U) and anthropogenic (137Cs,239+240Pu, and241Am) radionuclides in marine sediment from the Baltic Sea (IAEA-465) has been developed. Information values are given for 238Pu,239Pu and240Pu. Altogether 27 laboratories participated in this exercise. Radiometric (alpha-spectrometry, gamma-spectrometry and beta counting, as well as mass spectrometry (ICP-MS and AMS) techniques were applied in measurements. The CRM is intended to be used for Quality Assurance/Quality Control of radionuclide analyses, for the development and validation of analytical methods, for the development of reference methods and for training purposes.
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Sedimentos Geológicos , Monitoramento de Radiação , Poluentes Radioativos da Água , Sedimentos Geológicos/química , Poluentes Radioativos da Água/análise , Plutônio/análise , Padrões de Referência , Radioisótopos/análise , Radioisótopos de Césio/análise , Tório/análiseRESUMO
The aim of this work was to improve the commonly used method for 226Ra determination in water and to establish its application in solid samples. This method is based on the coprecipitation of Ra with BaSO4 and gross alpha counting of the precipitate. An exhaustive study of the coprecipitation behaviour of the most abundant cations present in solid samples was performed to avoid incorrect radiochemical yields. As a result, it was considered necessary to introduce two new purification steps into the conventional method. Likewise, two nuclides, 241Am and 226Ra, were compared to obtain the mass efficiency curve given their different behaviour in the coprecipitation process. While Ra behaves similarly to Ba, Am coprecipitates, forming mixed crystals that may behave differently in the self-absorption process. The influence of the cations on the chemical yield with no precipitate purification was: Sr2+â«Fe3+>Mg2+≈Ca2+>K+≈Na+. The method was successfully applied to soil, sediment, and plant ash samples.
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Rádio (Elemento) , Poluentes Radioativos da Água , Radioquímica , Compostos Radiofarmacêuticos , Rádio (Elemento)/análise , Contagem de Cintilação/métodos , Poluentes Radioativos da Água/análiseRESUMO
Accurate measurement of naturally occurring radionuclides in blast furnace slag, a by-product of the steel industry, is required for compliance with building regulations where it is often used as an ingredient in cement. A matrix reference blast furnace slag material has been developed to support traceability in these measurements. Raw material provided by a commercial producer underwent stability and homogeneity testing, as well as characterisation of matrix constituents, to provide a final candidate reference material. The radionuclide content was then determined during a comparison exercise that included 23 laboratories from 14 countries. Participants determined the activity per unit mass for 226Ra, 232Th and 40K using a range of techniques. The consensus values obtained from the power-moderated mean of the reported participant results were used as indicative activity per unit mass values for the three radionuclides: A0(226Ra) = 106.3 (34) Bq·kg-1, A0(232Th) = 130.0 (48) Bq·kg-1 and A0(40K) = 161 (11) Bq·kg-1 (where the number in parentheses is the numerical value of the combined standard uncertainty referred to the corresponding last digits of the quoted result). This exercise helps to address the current shortage of NORM industry reference materials, putting in place infrastructure for production of further reference materials.
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Cement based materials may contain varying levels of radionuclides, mainly 226Ra (from the 238U series), 232Th and 40K, which are used to determine the Activity Concentration Index ("ACI"). According to the European directive Euratom 2013/59 in these materials, the "ACI" must be < 1 to be suitable for their use in construction. In this paper, data on the activity concentration of natural radionuclides in cement-based materials (i.e. cements, additions, pigments and aggregates) as well as their chemical composition are presented. Radioactivity measurements have been determined by using gamma spectroscopy the chemical compositions have been determined by X-Ray Fluorescence. Data for cements measured shown that white cements present a lower concentration of activity than conventional CEM I. In addition, the CAC (Calcium aluminate cements) present high activity concentration in the 232Th series. Regarding additions, FA (Fly Ash) are those that present the highest concentration of activity in the 238U and 232Th series, while olive biomass ashes are those supplementary cementitious materials that show the highest concentration of activity for 40K. Some pigments used in mortar and concrete technology were also characterized. Granitic and volcanic rocks, potentially used as aggregates present much higher activity concentration than the siliceous aggregate.
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This study explores the effect of 229Th tracer tail interference on the determination of the sensitivity of 230Th alpha spectrometry of samples with environmental levels of radioactivity. Tracer peak tail interference was calculated with Suma-Alpha, whilst Visual Basic for Applications (VBA in Excel©) software was used to study the variation in sensitivity in terms of the amount of tracer added. Unnecessary increases in the amount of tracer or extended sample measuring times were observed to have adverse effects on method sensitivity (Detection Limit- Ld).
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The γ-radiation emitted by building materials is calculated from the activity indices for 232Th, 226Ra and 40K and expressed as the activity concentration index (ACI). Gamma spectroscopy is a non-destructive technique frequently used to simultaneously determine the indices for several radionuclides. Spectral interpretation poses a number of challenges, including identification of γ-lines subject to summing-in effects, interference from other γ-ray emitting radionuclides and the time required to reach secular equilibrium. These challenges are not fully addressed by Canberra Industries' Genie 2000, the software used by many laboratories to analyse samples. This article describes a Microsoft Excel workbook that exploits Genie 2000 flexibility to program applications with Visual Basic using Canberra's Nuclear Data Access Library and batch procedure tools. The workbook determines 40K activity concentration after correcting for 228Ac interference and 226Ra activity directly from the γ-peak at 186.5â¯keV. The method proposed was tested by participating in 13 national and international scale inter-comparison exercises. The results were statistically indistinguishable from the reference values at a coverage factor of kâ¯=â¯3 and no statistically significant differences were identified between the respective means by a Student's t pairwise comparison.
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INTRODUCTION: Supra-glottic airway devices (SADs) with an inbuilt drain channel, such as the LMA Proseal™ (LMA-P), LMA SupremeTM (LMA-S) and i-gel™ (i-gel), have been used for laparoscopic cholecystectomy. We compared safety, efficacy, and ease of use, as well as the incidence of adverse events between these devices. METHODS: One hundred and eighty adult, ASA 1-3 patients scheduled to undergo elective cholecystectomy under general anesthesia were randomly allocated to one of three groups: LMA-P, LMA-S or i-gel. The primary outcome was to evaluate oropharyngeal leak pressure (OLP). Secondary outcomes were to evaluated speed of insertion, ease of insertion of the device and the drain tube, as well as the incidence of intraoperative adverse events and postoperative oropharyngeal discomfort (POPD). RESULTS: Mean OLP was significantly higher for LMA-P (LMA-P 30.87; i-gel 29.28; LMA-S 29.02 cm H20, P = 0.007). OLP was correlated with a higher maximum tidal achieved volume (P = 0.025). Insertion times were shorter for the i-gel, which was 1.7 s faster to insert than LMA-P (P = 0.04). The success rate on first attempt was higher for the LMA-S (P = 0.004). The drain tube was easily inserted in the LMA-S group (p < 0.001). I-gel showed higher sore throat scoring 2 hours postoperatively (P = 0.008) and reported slower POPD decrease during that time (P < 0.001). CONCLUSIONS: Among SAD's, LMA-S is the easiest to insert (including the drain tube), LMA-P achieved the best leak pressure, and i-gel fastest to insert, although associated with the worst POPD scoring.
Assuntos
Colecistectomia Laparoscópica/instrumentação , Máscaras Laríngeas , Adulto , Idoso , Anestesia Geral , Colecistectomia Laparoscópica/efeitos adversos , Transtornos de Deglutição/epidemiologia , Transtornos de Deglutição/etiologia , Disfonia/epidemiologia , Disfonia/etiologia , Desenho de Equipamento , Feminino , Humanos , Máscaras Laríngeas/efeitos adversos , Masculino , Pessoa de Meia-Idade , Conforto do Paciente , Segurança do Paciente , Faringite/epidemiologia , Faringite/etiologia , Complicações Pós-Operatórias/epidemiologia , Estudos ProspectivosRESUMO
The preparation and characterization of certified reference materials (CRMs) for radionuclide content in sediments collected offshore of Bikini Atoll (IAEA-410) and in the open northwest Pacific Ocean (IAEA-412) are described and the results of the certification process are presented. The certified radionuclides include: (40)K, (210)Pb ((210)Po), (226)Ra, (228)Ra, (228)Th, (232)Th, (234)U, (238)U, (239)Pu, (239+240)Pu and (241)Am for IAEA-410 and (40)K, (137)Cs, (210)Pb ((210)Po), (226)Ra, (228)Ra, (228)Th, (232)Th, (235)U, (238)U, (239)Pu, (240)Pu and (239+240)Pu for IAEA-412. The CRMs can be used for quality assurance and quality control purposes in the analysis of radionuclides in sediments, for development and validation of analytical methods and for staff training.
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Sedimentos Geológicos/análise , Radioisótopos/análise , Radioisótopos/normas , Radiometria/normas , Poluentes Radioativos do Solo/análise , Poluentes Radioativos do Solo/normas , Certificação/normas , Sedimentos Geológicos/química , Micronésia , Oceano Pacífico , Radioisótopos/química , Valores de Referência , Poluentes Radioativos do Solo/químicaRESUMO
BACKGROUND: The LMA Supreme(TM) (LMA-S) and i-gel(TM) are two of the most commonly used supraglottic airway devices (SADs) with an inbuilt drain channel. These devices are particularly indicated for performing certain procedures accompanied by high peak airway pressure, such as laparoscopy. This study compared the devices regarding efficacy, safety, ease of use and incidence of adverse events, focusing on the postoperative rate of sore throat, dysphagia or dysphonia and development with time, in patients undergoing laparoscopic cholecystectomy procedures under general anesthesia. METHODS: This was a prospective, randomized, controlled clinical study including 140 patients randomized into 2 groups undergoing elective laparoscopic cholecystectomy to use either i-gel or LMA-S. After the general anesthesia procedure, the speed of insertion, success rates, ease of insertion of the drain tube, leak pressure and tidal volume achieved by the devices were evaluated. The postoperative oropharyngeal discomfort (POPD) during the period of stay of the patients in the recovery room was also recorded. RESULTS: The mean leak pressure was comparable between the two groups (i-gel 28.18 ± 3.90 cmH2O and LMA-S 27.50 ± 4 cmH2O, p = 0.09), as well as maximum expiratory tidal volume provided (i-gel 559.60 ± 45.25 ml and LMA-S 548.95 ± 56.18 ml, p = 0.12). Insertion times were lower for the i-gel (10 ± 1.62 s) compared with the LMA-S (11.31 ± 2.85 s, p = 0.008). Insertion success rate at the first attempt was higher for the LMA-S (95 % compared with i-gel 79 %, p = 0.007). Drain tubes were easier to insert in the LMA-S group (p < 0.001). No differences were found between groups relating to intraoperative complications. Frequency of coughing and visible blood on removal of the device were low and comparable in both groups (p = 0.860 and p = 0.623, respectively). There were no differences relating to the incidence of sore throat, dysphagia or hoarseness at 10 min postoperatively between groups (p = 0.088). The i-gel group complained about a higher sore throat score at 2 h postoperatively (p = 0.009), specifically patients receiving i-gel suffered more from sore throats with 0.24 more points on the visual analog scale (VAS) than patients from the LMA-S group. The i-gel group also reported a lower POPD drop during the first 2 h (p < 0.001). CONCLUSION: No differences were found between i-gel and LMA-S regarding leak pressure in the groups of anesthetized patients undergoing laparoscopic cholecystectomy. The LMA-S was easier to insert than the i-gel (based on its better first time success rate) and this device showed better ease of drain tube insertion, although the i-gel was quicker to insert than the LMA-S. The i-gel resulted in higher sore throat scores at 2 h postoperatively and lower POPD reduction during the 2 h period studied in the recovery room was reported.
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Máscaras Laríngeas/efeitos adversos , Adulto , Pressão do Ar , Anestesia Geral , Anestésicos , Colecistectomia Laparoscópica/métodos , Tosse/epidemiologia , Transtornos de Deglutição/etiologia , Feminino , Humanos , Complicações Intraoperatórias/epidemiologia , Masculino , Pessoa de Meia-Idade , Orofaringe/lesões , Segurança do Paciente , Faringite/epidemiologia , Faringite/etiologia , Complicações Pós-Operatórias/epidemiologia , Estudos ProspectivosRESUMO
A Certified Reference Material (CRM) for radionuclides in seaweed (Fucus vesiculosus) from the Baltic Sea (IAEA-446) is described and the results of the certification process are presented. The (40)K, (137)Cs, (234)U and (239+240)Pu radionuclides were certified for this material, and information values for 12 other radionuclides ((90)Sr, (99)Tc, (210)Pb ((210)Po), (226)Ra, (228)Ra, (228)Th, (230)Th, (232)Th, (235)U, (238)U, (239)Pu and (240)Pu) are presented. The CRM can be used for Quality Assurance/Quality Control of analysis of radionuclides in seaweed and other biota samples, as well as for development and validation of analytical methods, and for training purposes.
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Alga Marinha/química , Poluentes Radioativos da Água/análise , Países Bálticos , Padrões de Referência , Poluentes Radioativos da Água/normasRESUMO
The vertical activity distribution and inventories of (239+240)Pu profile and Hg were determined in Sagua la Grande estuary, Cuba. The shape of the (239+240)Pu profile in the core column resembled very closely the history of atmospheric nuclear weapons' testing, and the maximum deposition in 1963 was recorded in the sediment core history. The (239+240)Pu activity concentrations in the surface layer sediments varied from 0.163 to 0.611 mBq g(-1). The inventory of (239+240)Pu was 42 ± 5.6 Bq m(-2), a value close to that expected from direct global fallout. Using the (239+240)Pu as a chronomarker the mass sedimentation rate in the area for the last 60 years was calculated, reaching values of 0.173 g cm(-2) y(-1). The mercury profile reflects the history of anthropogenic pollution in the estuary and perfectly describes the operation of the mercury-cell chlor-alkali plant, for production of NaOH, which began operations in 1980. The inventory of Hg was 2.42 ± 0.19 µg cm(-2). These results contribute to the scarce regional database for pollutants and anthropogenic radionuclides in the Caribbean marine environment, particularly in relation to (239+240)Pu.
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Sedimentos Geológicos/química , Mercúrio/análise , Plutônio/análise , Poluentes Químicos da Água/análise , Poluentes Radioativos da Água/análise , Cuba , Monitoramento de RadiaçãoRESUMO
A new Certified Reference Material (CRM) for radionuclides in sediment (IAEA-385) is described and the results of the certification process are presented. Eleven radionuclides ((40)K, (137)Cs, (226)Ra, (228)Ra, (230)Th, (232)Th, (234)U, (238)U, (238)Pu, (239+240)Pu and (241)Am) have been certified and information mass activities with 95% confidence intervals are given for seven other radionuclides ((90)Sr, (210)Pb((210)Po), (235)U, (239)Pu, (240)Pu and (241)Pu). Results for less frequently reported radionuclides ((60)Co, (99)Tc, (134)Cs, (155)Eu, (224)Ra and (239)Np) and information on some activity and mass ratios are also reported. The CRM can be used for quality assurance/quality control of the analysis of radionuclides in sediment samples, for the development and validation of analytical methods and for training purposes.
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Sedimentos Geológicos/análise , Guias de Prática Clínica como Assunto , Monitoramento de Radiação/normas , Radioisótopos/análise , Radioisótopos/normas , Irlanda , Oceanos e Mares , Doses de Radiação , Valores de ReferênciaRESUMO
The dispersion and fate of the Rhone River inputs to the Gulf of Lions (Northwestern Mediterranean Sea) have been studied through the spatial and temporal distributions of plutonium isotopes in continental shelf sediments. Plutonium isotopes ((238)Pu and (239,240)Pu) are appropriate tracers to follow the dispersion of particulate matter due both to their high affinity for particles and their long half-lives. In the Rhone River valley, plutonium isotopes originate from both the weathering of the catchment basin contaminated by global atmospheric fallout, and the liquid effluents released from the Marcoule reprocessing plant since 1961. This work presents a first detailed study on (238)Pu and (239,240)Pu distributions in sediments from the Rhone prodelta to the adjacent continental shelf, since the decommissioning of Marcoule in 1997. The vertical distribution of Pu isotopes has been analysed in a 4.75 m long core sampled in 2001 at the Rhone mouth. Despite this length, plutonium is found at the last 10 cm, manifesting the high sedimentation rate of the prodeltaic area and its ability for trapping fine-grained sediments and associated contaminants. The highest (238)Pu and (239,240)Pu concentrations reached 1.26 and 5.97 Bq kg(-1) respectively and were found within the layer 280-290 cm. The (238)Pu/(239,240)Pu activity ratios (AR) demonstrated an efficient and huge trapping of the Pu isotopes derived from Marcoule. The fresh sediments, located on the top of the core, show lower plutonium activity concentrations and lower (238)Pu/(239,240)Pu ratios. This decrease is in close relation with the shut down of the Marcoule reprocessing plant in 1997. In 2001, plutonium isotopes were also analysed in 21 surface sediments located offshore and concentrations ranged from 0.03 to 0.17 Bq kg(-1) for (238)Pu and from 0.33 to 1.72 Bq kg(-1) for (239,240)Pu. The (238)Pu/(239,240)Pu AR ranged from 0.24 close to the river mouth to 0.06 southwards, indicating the decreasing influence of the Marcoule releases (global fallout AR 0.03-0.05 and Marcoule AR 0.30). This is in good agreement with the main direction spread of the Rhone River plume and the bottom current. This dataset has been compared to those obtained in the same area in 1984 and 1990 in order to follow the time trend in Pu concentrations. This comparison highlights the decrease with time in plutonium concentrations close to the Rhone River mouth, but further away this reduction is not so evident.
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Sedimentos Geológicos/análise , Plutônio/análise , Poluentes Radioativos da Água/análise , Monitoramento Ambiental , França , Resíduos Radioativos , Rios , Fatores de TempoRESUMO
Within an extensive multinational and multidisciplinary project carried out in Doñana National Park (Spain) to investigate its preservation and regeneration, the filling velocity of the salt marshes has been evaluated through the calculation of their average sediment accumulation rates. (239+240)Pu and (137)Cs from weapons testing fallout and total (210)Pb distribution profiles and inventories have been determined in some of the most characteristic zones of the park, namely, the ponds (or "lucios") and the waterjets (or "caños"). Plutonium inventories range from 16 to 101 Bq m(-2), (137)Cs values fluctuate between 514 and 3,758 Bq m(-2) and unsupported (210)Pb values comprise between 124 and 9398 Bq m(-2). Average sedimentation rates range from 3 to 5 mm y(-1) (1952-2002). These data are higher than those obtained by carbon dating for the period 6,500 AD-present, estimated as 1.5-2 mm y(-1), suggesting an increase in the accumulation of sediments and the alteration of the park's hydrodynamics caused by the re-channeling of the major rivers feeding the salt marshes.
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Radioisótopos de Césio/análise , Radioisótopos de Chumbo/análise , Plutônio/análise , Cinza Radioativa/análise , Água do Mar/química , Áreas Alagadas , Sedimentos Geológicos/química , Humanos , Radioisótopos , Poluentes Radioativos do Solo/análise , Espanha , Poluentes Radioativos da Água/análise , Contaminação Radioativa da Água/análiseRESUMO
A certified reference material (CRM) for radionuclides in fish sample IAEA-414 (mixed fish from the Irish Sea and North Seas) is described and the results of the certification process are presented. Nine radionuclides (40K, 137Cs, 232Th, 234U, 235U, 238U, 238Pu, 239+240Pu and 241Am) were certified for this material. Information on massic activities with 95% confidence intervals is given for six other radionuclides (90Sr, 210Pb(210Po), 226Ra, 239Pu, 240Pu 241Pu). Less frequently reported radionuclides (99Tc, 129I, 228Th, 230Th and 237Np) and information on some activity and mass ratios are also included. The CRM can be used for quality assurance/quality control of the analysis of radionuclides in fish sample, for the development and validation of analytical methods and for training purposes. The material is available from IAEA, Vienna, in 100 g units.
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Peixes/metabolismo , Guias como Assunto , Monitoramento de Radiação/métodos , Monitoramento de Radiação/normas , Radioisótopos/análise , Radioisótopos/normas , Padrões de Referência , Animais , Cooperação Internacional , Irlanda , Oceanos e Mares , Doses de Radiação , Valores de Referência , Reprodutibilidade dos Testes , Sensibilidade e EspecificidadeRESUMO
The National Institute of Standards and Technology (NIST) Standard Reference Material (SRM) for seaweed was developed through an interlaboratory comparison with 24 participants from 16 countries. After evaluating different techniques to calculate certified values for the radionuclides, the median method was found to be the most representative technique. The certified values were provided for 13 radionuclides and information values were given for 15 more radionuclides. Results for the natural decay series showed disequilibrium in both the uranium and thorium series.
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Guias como Assunto , Monitoramento de Radiação/normas , Radioisótopos/análise , Radioisótopos/normas , Padrões de Referência , Alga Marinha/química , Poluentes Radioativos da Água/análise , Cooperação Internacional , Doses de Radiação , Monitoramento de Radiação/métodos , Valores de Referência , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Poluentes Radioativos da Água/normasRESUMO
The activity concentrations and fluxes of natural (210Pb, 210Po) and anthropogenic (239,240Pu, 137Cs) radionuclides have been determined in the different water masses crossing the Strait of Gibraltar. New data have been gathered during four multidisciplinary and multinational sampling campaigns, performed between 1997 and 1999 within the framework of the CANIGO-FLUGIST Project. Mean activity concentrations of 210Po (1.53+/-0.34 Bq m(-3), n = 30) and 210Pb (1.16+/-0.50 Bq m(-3), n = 31) in the Atlantic water entering the Mediterranean basin are about double those measured in the Mediterranean outflow, namely 0.84+/-0.34 Bq m(-3) (n = 22) for 210Po and 0.66+/-0.34 Bq m(-3) (n = 22) for 210Pb. The opposite trend is observed for 231,240Pu, with average concentrations of 9.9+/-3.0 mBq m(-3) (n = 29) in the incoming Atlantic flow and 22.0+/-3.0 mBq m(-3) (n = 22) in the outpouring Mediterranean water. In the case of 137Cs, the same concentrations were quantified in the waters moving inwards (2.52+/-0.28 Bq m(-3), n = 27) and outwards (2.14+/-0.52 Bq m(-3), n = 21) from the Mediterranean Sea. On this basis, the Mediterranean basin experiences a net annual input flux of 14 TBq of 210Pb and 19 TBq of 210Po, and a net annual loss of 0.34 TBq of 239,240Pu, while--at present--137Cs input and output fluxes appear to be balanced.
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Radioisótopos/análise , Poluentes Radioativos da Água/análise , Radioisótopos de Césio/análise , Monitoramento Ambiental , Radioisótopos de Chumbo/análise , Plutônio/análise , Polônio/análise , Espanha , Movimentos da ÁguaRESUMO
Continental margins are important areas to be considered when studying the distributions and depositions of pollutants, both conventional and radioactive. Coastal sediments accumulate most of those contaminants which can be introduced following atmospheric and/or fluvial pathways. Moreover, their residence times within the water column are usually shortened due to their affinity to associate with the downward falling particulate matter, more abundant at shallower depths. In this paper the distribution profiles and inventories of plutonium, americium and cesium are detailed, providing useful information about recent sedimentation phenomena such as sediment mixing, slumping processes and bioturbation. Unsupported 210Pb data are used as reliable indicators of enhanced/reduced deposition events. Also, the calculated inventories have enabled the estimation of the radiological contribution of the Spanish Mediterranean margin to the total radioactivity deposited onto the Mediterranean sea floor.
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Poluentes Radioativos do Ar/análise , Monitoramento Ambiental , Poluentes Ambientais , Sedimentos Geológicos/química , Poluentes Radioativos da Água/análise , Amerício/análise , Radioisótopos de Césio/análise , Plutônio/análise , Movimentos da ÁguaRESUMO
INTRODUCTION: Although life threatening emergencies in dental practice are not frequent, dentists have to be competent in providing basic life support (BLS). OBJECTIVES: The aim of this work was to study the level of skills acquisition among dentistry students in two different periods of one rescuer-BLS training, a first short practice training of 2 h followed by 8 h of practice over a period of 2 months. METHODS: One hundred and sixteen second-year undergraduate students of Anesthesiology at the Dental School of the Complutense University in Madrid were tested at the end of the two periods of learning using a recording manikin with a validated scoring system (Laerdal Resusci-Anne). This manikin recorded the percentage of adequate chest compressions and insuflations, rate of chest compressions and the causes of error in each case. RESULTS: Final global results were, 51.66+/-3.0% adequate chest compressions; and 54.44+/-3.61% adequate insuflations. The kinds of errors where different in both tests were, wrong hand position (26.92+/-2.96 vs. 12.29+/-2.40%, P<0.001); excessive compressions (27.71+/-2.90 vs. 16.02+/-2.33%, P<0.05); and weak compressions (23.28+/-3.24 vs. 16.77+/-2.57%, P<0.05). Regression analysis found a positive correlation among excessive compression, height and weight (P<0.001) and a negative correlation between weak compression, height and weight (P<0.001). CONCLUSIONS: The poor overall results, although similar to those shown in the literature, have made us question the validity of our methods of teaching BLS. We were able to establish a correlation between demographic and sociocultural variables with the typical errors, and to begin the process of improving our teaching methods.
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Reanimação Cardiopulmonar/educação , Educação em Odontologia , Adulto , Competência Clínica , Avaliação Educacional , Feminino , Humanos , Masculino , Análise de Regressão , Espanha , Ensino/métodosRESUMO
It is well established that the main source of the plutonium found in marine sediments throughout the Northern Hemisphere is global stratospheric fallout, characterized by a typical 240Pu/239Pu atom ratio of approximately 0.18. Measurement of perturbations in this ratio at various sites which had been subjected to close-in fallout, mainly from surface-based testing (e.g. Bikini Atoll, Nevada test site, Mururoa Atoll), has confirmed the feasibility of using this ratio to distinguish plutonium from different fallout sources. In the present study, the 240Pu/239Pu ratio has been examined in samples of sediment (and soil) collected at Thule (Greenland) and Palomares (Spain), where accidents involving the release and dispersion of plutonium from fractured nuclear weapons occurred in 1968 and 1966, respectively. The 240Pu/239Pu ratio was measured by high-resolution alpha spectrometry and spectral deconvolution, and confirmed in the case of the most active samples by high-resolution X-ray spectrometry. Only samples which displayed plutonium heterogeneities, i.e. hot particles or concentrations well in excess (at least two orders of magnitude) of those expected from global fallout, were selected for analysis. The analytical results showed that at Thule the mean 240Pu/239Pu atom ratio was 0.033 +/- 0.004 (n = 4), while at Palomares the equivalent ratio appeared to be significantly higher at 0.056 +/- 0.003 (n = 4). Both ratios are indicative of low burn-up plutonium and are consistent with those reported for weapons-grade plutonium. It is noteworthy that the mean 238Pu/239Pu activity ratio in the Thule samples, at 0.0150 +/- 0.0017 (n = 4), was also lower than that measured in the Palomares samples, namely, 0.0275 +/- 0.0012 (n = 4). The 241Pu/239Pu ratios were similarly different. Finally, the data show, in contrast to Palomares, that not all of the samples from the Thule accident site were contaminated with plutonium of identical isotopic composition.