RESUMO
BACKGROUND: This study examined perceptions of coercion, pressures and procedural injustice and how such perceptions influenced psychological well-being in those who experienced a UK COVID-19 lockdown, with a view to preparing for the possibility of future lockdowns. METHODS: 40 individuals categorised as perceiving the lockdown(s) as either highly or lowly coercive took part in one of six asynchronous virtual focus groups (AVFGs). RESULTS: Using thematic analysis, the following key themes were identified in participants' discussions: (1) Choice, control and freedom; (2) threats; (3) fairness; (4) circumstantial factors; and (5) psychological factors. CONCLUSIONS: As the first qualitative study to investigate the psychological construct of perceived coercion in relation to COVID-19 lockdowns, its findings suggest that the extent to which individuals perceived pandemic-related lockdowns as coercive may have been linked to their acceptance of restrictions. Preparing for future pandemics should include consideration of perceptions of coercion and efforts to combat this, particularly in relation to differences in equity, in addition to clarity of public health messaging and public engagement.
Assuntos
COVID-19 , Coerção , Humanos , Pandemias/prevenção & controle , COVID-19/prevenção & controle , Controle de Doenças Transmissíveis , Justiça Social , Reino Unido/epidemiologiaRESUMO
Paranoia is a common symptom of psychotic disorders but is also present on a spectrum of severity in the general population. Although paranoia is associated with an increased tendency to perceive cohesion and conspiracy within groups, the mechanistic basis of this variation remains unclear. One potential avenue involves the brain's dopaminergic system, which is known to be altered in psychosis. In this study, we used large-N online samples to establish the association between trait paranoia and perceptions of cohesion and conspiracy. We further evaluated the role of dopamine on perceptions of cohesion and conspiracy using a double-blind, placebo-controlled laboratory experiment where participants received levodopa or a placebo control. Our results were mixed: group perceptions and perceptions of cohesion were higher among more paranoid individuals but were not altered under dopamine administration. We outline the potential reasons for these discrepancies and the broader implications for understanding paranoia in terms of dopamine dysregulation.
Assuntos
Transtornos Paranoides , Transtornos Psicóticos , Humanos , Dopamina , Transtornos Paranoides/tratamento farmacológico , Percepção , Método Duplo-CegoRESUMO
Jaggery is a kind of unrefined non-centrifugal sugar (NCS) used mainly in Asia, Africa, Latin America, and the Caribbean. Traditionally, jaggery is produced by concentrating sugarcane juice in open pans with the help of bagasse combustion. However, due to thermal energy loss with flue gases and an unscientific approach in plant construction, jaggery plants have a poor thermal efficiency of less than 25%, poor emission characteristics, and a high bagasse consumption rate. Advanced jaggery-making techniques use solar energy and heat pumps for jaggery production. However, these techniques are in the early stage of development, and the literature indicates that these techniques should be used in conjuction with traditional ones to improve the performance of jaggery making plants. This literature review describes advances in jaggery-making methods, critically analyzed them, and provides a qualitative comparison of these methods. Further, gaps in the existing literature are identified and reported for future research direction. In addition, efforts have been made to quantify and estimate the emissions reduction and bagasse consumption potentials from the traditional jaggery industry to make this rural industry a sustainable and profitable business for rural entrepreneurs. The comparison with the recently developed clean combustion device exhibits that the harmful emissions from the jaggery industry could be reduced drastically viz. 95%-98% of PM2.5; 92%-95% of CO, and 52-60% of CO2, while saving more than 35% of bagasse consumption. Implemented at a national scale, it may reduce nearly 3% of all harmful emissions in the country, which is equally applicable elsewhere.
Assuntos
Extratos Vegetais , Saccharum , Gases , Temperatura AltaRESUMO
Weakening drinking-related reward memories by blocking their reconsolidation is a potential novel strategy for treating alcohol use disorders. However, few viable pharmacological options exist for reconsolidation interference in humans. We therefore examined whether the NMDA receptor antagonising gas, Nitrous Oxide (N2O) could reduce drinking by preventing the post-retrieval restabilisation of alcohol memories in a group of hazardous drinkers. Critically, we focussed on whether prediction error (PE; a key determinant of reconsolidation) was experienced at retrieval. Sixty hazardous drinkers were randomised to one of three groups that retrieved alcohol memories either with negative PE (Retrieval + PE), no PE (Retrieval no PE) or non-alcohol memory retrieval with PE (No-retrieval +PE). All participants then inhaled 50% N2O for 30â¯min. The primary outcome was change in beer consumption and alcohol cue-driven urge to drink from the week preceding manipulation (baseline) to the week following manipulation (test). The manipulation did not affect drinking following the intended retrieval+/- PE conditions However, a manipulation check, using a measure of subjective surprise, revealed that the group-level manipulation did not achieve the intended differences in PE at retrieval. Assessment of outcomes according to whether alcohol-relevant PE was actually experienced at retrieval, showed N2O produced reductions in drinking in a retrieval and PE-dependent fashion. These preliminary findings highlight the importance of directly testing assumptions about memory reactivation procedures in reconsolidation research and suggest that N2O should be further investigated as a potential reconsolidation-blocking agent.
Assuntos
Consumo de Bebidas Alcoólicas/tratamento farmacológico , Consumo de Bebidas Alcoólicas/psicologia , Consolidação da Memória/efeitos dos fármacos , Rememoração Mental/efeitos dos fármacos , Óxido Nitroso/uso terapêutico , Adulto , Idoso , Anestésicos Inalatórios/uso terapêutico , Fissura/efeitos dos fármacos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Adulto JovemRESUMO
BACKGROUND: Post-traumatic stress disorder (PTSD) involves maladaptive long-term memory formation which underlies involuntary intrusive thoughts about the trauma. Preventing the development of such maladaptive memory is a key aim in preventing the development of PTSD. We examined whether the N-methyl d-aspartate receptor (NMDAR) antagonist gas nitrous oxide (N2O) could reduce the frequency of intrusive memories by inhibiting NMDAR-dependent memory consolidation in a laboratory analogue of psychological trauma. METHOD: Participants were randomized to inhale N2O (N = 25) or medical air (N = 25) after viewing a negatively valenced emotional film clip ('trauma film'). Participants subsequently completed a daily diary assessing frequency of intrusive thoughts relating to the film clip. A week later, participants completed an explicit memory recall task related to the film. RESULTS: Post-encoding N2O sped the reduction in intrusive memory frequency, with a significant reduction by the next day in the N2O group compared to 4 days later in the air group. N2O also interacted with post-film dissociation, producing increased intrusion frequency in those who were highly dissociated at baseline. Sleep length and quality the night after viewing the film did not differ between the groups. CONCLUSION: N2O speeds the reduction of intrusive analogue trauma memory in a time-dependent manner, consistent with sleep-dependent long-term consolidation disruption. Further research with this drug is warranted to determine its potential to inoculate against enduring effects of psychological trauma; however, caution is also urged in dissociated individuals where N2O may aggravate PTSD-like symptomatology.
Assuntos
Analgésicos não Narcóticos/farmacologia , Consolidação da Memória/efeitos dos fármacos , Óxido Nitroso/farmacologia , Trauma Psicológico/psicologia , Adolescente , Adulto , Feminino , Frequência Cardíaca , Humanos , Masculino , Memória/efeitos dos fármacos , Rememoração Mental/efeitos dos fármacos , Modelos Teóricos , Trauma Psicológico/fisiopatologia , Sono , Transtornos de Estresse Pós-Traumáticos/psicologia , Adulto JovemRESUMO
We report an inter-comparison of eight models designed to predict the radiological exposure of radionuclides in marine biota. The models were required to simulate dynamically the uptake and turnover of radionuclides by marine organisms. Model predictions of radionuclide uptake and turnover using kinetic calculations based on biological half-life (TB1/2) and/or more complex metabolic modelling approaches were used to predict activity concentrations and, consequently, dose rates of (90)Sr, (131)I and (137)Cs to fish, crustaceans, macroalgae and molluscs under circumstances where the water concentrations are changing with time. For comparison, the ERICA Tool, a model commonly used in environmental assessment, and which uses equilibrium concentration ratios, was also used. As input to the models we used hydrodynamic forecasts of water and sediment activity concentrations using a simulated scenario reflecting the Fukushima accident releases. Although model variability is important, the intercomparison gives logical results, in that the dynamic models predict consistently a pattern of delayed rise of activity concentration in biota and slow decline instead of the instantaneous equilibrium with the activity concentration in seawater predicted by the ERICA Tool. The differences between ERICA and the dynamic models increase the shorter the TB1/2 becomes; however, there is significant variability between models, underpinned by parameter and methodological differences between them. The need to validate the dynamic models used in this intercomparison has been highlighted, particularly in regards to optimisation of the model biokinetic parameters.
Assuntos
Organismos Aquáticos/metabolismo , Radioisótopos de Césio/metabolismo , Radioisótopos do Iodo/metabolismo , Modelos Teóricos , Monitoramento de Radiação/métodos , Radioisótopos de Estrôncio/metabolismo , Poluentes Radioativos da Água/metabolismo , Animais , Crustáceos/metabolismo , Peixes/metabolismo , Moluscos/metabolismo , Alga Marinha/metabolismoRESUMO
The transient period of memory instability that can be triggered when memories are retrieved under certain conditions offers an opportunity to modify the maladaptive memories at the heart of substance use disorders (SUDs). However, very well-learned memories (such as those in excessive drinking and alcohol use disorders) are resistant to destabilisation when retrieved or may not destabilise at all. Memory retrieval and intervention procedures that reliably destabilise and update maladaptive motivational memories may help to improve the long-term treatment of SUDs. In 59 hazardous drinkers, we tested a novel retrieval procedure for destabilising well-learned cue-drinking memory networks that maximises prediction error (PE) via guided expectancy violation during retrieval of these memories. This was compared with a retrieval procedure without PE and no-retrieval controls. We subsequently counterconditioned alcohol cues with disgusting tastes and images in all groups and assessed responding to alcohol stimuli 1 week later. Counterconditioning following PE retrieval produced generalised reductions in oculomotor attentional bias, explicit valuation and outcome expectancies in response to alcohol cues 1 week after intervention, evidence of updating of distributed motivational drinking memory networks. These findings demonstrate that well-learned cue-drinking memories can be destabilised and that learning history need not constrain memory destabilisation if PE is maximised at retrieval. Broad rewriting of diverse aspects of maladaptive memory by counterconditioning is achievable following this procedure. The procedure described may provide a platform for the development of novel memory-modifying interventions for SUDs.
Assuntos
Transtorno Amnésico Alcoólico , Consumo de Bebidas Alcoólicas , Adolescente , Adulto , Transtorno Amnésico Alcoólico/fisiopatologia , Transtorno Amnésico Alcoólico/psicologia , Transtorno Amnésico Alcoólico/terapia , Consumo de Bebidas Alcoólicas/fisiopatologia , Consumo de Bebidas Alcoólicas/psicologia , Sinais (Psicologia) , Retroalimentação Fisiológica , Humanos , Masculino , Consolidação da Memória , Transtornos da Memória/etiologia , Transtornos da Memória/fisiopatologia , Transtornos da Memória/psicologia , Rememoração Mental/fisiologia , Motivação/fisiologia , Neuropsicologia/métodos , Técnicas Psicológicas , Reprodutibilidade dos Testes , Reversão de Aprendizagem/fisiologiaRESUMO
BACKGROUND: The effects of opioid medication on cognitive functioning in patients with cancer and non-cancer pain remain unclear. METHOD: In this mechanistic randomized, double-blind, placebo-controlled, cross-over study of patients (n = 20) receiving sustained-release and immediate-release opioid medication as part of their palliative care, we examine memory effects of an additional dose of participants' immediate-release medication (oxycodone or morphine) or placebo. Immediate prose recall and recall of related and unrelated word pairs was assessed pre-and post-drug (placebo or immediate-release opioid). Memory for these stimuli was also tested after a delay on each testing occasion. Finally, performance on an 'interference' word pair task was assessed on the two testing occasions since proactive interference has been posited as a mechanism for acute opioid-induced memory impairment. RESULT: Unlike previous work, we found no evidence of memory impairment for material presented before or after individually tailored, 'breakthrough' doses of immediate-release opioid. Furthermore, immediate-release opioid did not result in increased memory interference. On the other hand, we found enhanced performance on the interference word pair task after immediate-release opioid, possibly indicating lower levels of interference. CONCLUSION: These results suggest that carefully titrated immediate-release doses of opioid drugs may not cause extensive memory impairment as previously reported, and in fact, may improve memory in certain circumstances. Importantly, our findings contrast strikingly with those of a study using the same robust design that showed significant memory impairment. We propose that factors, such as depressive symptoms, education level and sustained-release opioid levels may influence whether impairment is observed following immediate-release opioid treatment.
Assuntos
Afeto/efeitos dos fármacos , Analgésicos Opioides/farmacologia , Dor Irruptiva/tratamento farmacológico , Rememoração Mental/efeitos dos fármacos , Morfina/farmacologia , Oxicodona/farmacologia , Idoso , Analgésicos Opioides/uso terapêutico , Dor Irruptiva/etiologia , Preparações de Ação Retardada , Método Duplo-Cego , Feminino , Humanos , Masculino , Memória/efeitos dos fármacos , Pessoa de Meia-Idade , Morfina/uso terapêutico , Neoplasias/complicações , Testes Neuropsicológicos , Oxicodona/uso terapêutico , Dor/tratamento farmacológico , Dor/etiologiaRESUMO
The RESRAD-BIOTA Level 1 default Biota Concentration Guides (BCGs) are generic screening environmental medium concentrations based on reasonably conservative concentration ratios (CRs). These CRs had been identified from available literature for a variety of biota organisms. The International Atomic Energy Agency (IAEA) Technical Report Series (TRS) handbook on radionuclide transfer to wildlife was recently published with data that can be compared with the RESRAD-BIOTA values. In addition, previous IAEA Environmental Modeling for Radiation Safety (EMRAS) II Biota Working Group model comparison results are examined by comparing them with those obtained using the new TRS CR values for wildlife. Since the CR affects only internal doses, the effect on the overall dose depends on the relative contribution from internal and external exposure pathways.
Assuntos
Biota , Modelos Teóricos , Radioisótopos/metabolismo , Animais , Monitoramento de RadiaçãoRESUMO
Whole-organism concentration ratios (CRwo-media) for plutonium (Pu) in wildlife were calculated using data from the broad range of organism types and environmental settings of the US nuclear research program. Original sources included site-specific reports and scientific journal articles typically from 1960s to 80s research. Most of the calculated CRwo-media values are new to existing data sets, and, for some wildlife categories, serve to fill gaps or add to sparse data including those for terrestrial reptile; freshwater bird, crustacean and zooplankton; and marine crustacean and zooplankton. Ratios of Pu concentration in the whole-organism to that in specific tissues and organs are provided here for a range of freshwater and marine fish. The CRwo-media values in fish living in liquid discharge ponds were two orders of magnitude higher than those for similar species living in lakes receiving Pu from atmospheric fallout, suggesting the physico-chemical form of the source Pu can dominate over other factors related to transfer, such as organism size and feeding behavior. Small rodent data indicated one to two order of magnitude increases when carcass, pelt, and gastrointestinal tract were included together in the whole-organism calculation compared to that for carcass alone. Only 4% of Pu resided in the carcass of small rodents compared to 75% in the gastrointestinal tract and 21% in the pelt.
Assuntos
Plutônio/análise , Plutônio/metabolismo , Monitoramento de Radiação , Animais , Aves/metabolismo , Crustáceos/química , Crustáceos/metabolismo , Água Doce , Cinza Radioativa , Zooplâncton/química , Zooplâncton/metabolismoRESUMO
Radiological doses to terrestrial wildlife were examined in this model inter-comparison study that emphasised factors causing variability in dose estimation. The study participants used varying modelling approaches and information sources to estimate dose rates and tissue concentrations for a range of biota types exposed to soil contamination at a shallow radionuclide waste burial site in Australia. Results indicated that the dominant factor causing variation in dose rate estimates (up to three orders of magnitude on mean total dose rates) was the soil-to-organism transfer of radionuclides that included variation in transfer parameter values as well as transfer calculation methods. Additional variation was associated with other modelling factors including: how participants conceptualised and modelled the exposure configurations (two orders of magnitude); which progeny to include with the parent radionuclide (typically less than one order of magnitude); and dose calculation parameters, including radiation weighting factors and dose conversion coefficients (typically less than one order of magnitude). Probabilistic approaches to model parameterisation were used to encompass and describe variable model parameters and outcomes. The study confirms the need for continued evaluation of the underlying mechanisms governing soil-to-organism transfer of radionuclides to improve estimation of dose rates to terrestrial wildlife. The exposure pathways and configurations available in most current codes are limited when considering instances where organisms access subsurface contamination through rooting, burrowing, or using different localised waste areas as part of their habitual routines.
Assuntos
Modelos Biológicos , Doses de Radiação , Monitoramento de Radiação/métodos , Resíduos Radioativos/análise , Radioisótopos/análise , Poluentes Radioativos do Solo/análise , Animais , Ecossistema , New South Wales , Plantas/química , Plantas/efeitos dos fármacos , Radioisótopos/farmacocinética , Poluentes Radioativos do Solo/farmacocinéticaRESUMO
An exercise to compare 10 approaches for the calculation of unweighted whole-body absorbed dose rates was conducted for 74 radionuclides and five of the ICRP's Reference Animals and Plants, or RAPs (duck, frog, flatfish egg, rat and elongated earthworm), selected for this exercise to cover a range of body sizes, dimensions and exposure scenarios. Results were analysed using a non-parametric method requiring no specific hypotheses about the statistical distribution of data. The obtained unweighted absorbed dose rates for internal exposure compare well between the different approaches, with 70% of the results falling within a range of variation of ±20%. The variation is greater for external exposure, although 90% of the estimates are within an order of magnitude of one another. There are some discernible patterns where specific models over- or under-predicted. These are explained based on the methodological differences including number of daughter products included in the calculation of dose rate for a parent nuclide; source-target geometry; databases for discrete energy and yield of radionuclides; rounding errors in integration algorithms; and intrinsic differences in calculation methods. For certain radionuclides, these factors combine to generate systematic variations between approaches. Overall, the technique chosen to interpret the data enabled methodological differences in dosimetry calculations to be quantified and compared, allowing the identification of common issues between different approaches and providing greater assurance on the fundamental dose conversion coefficient approaches used in available models for assessing radiological effects to biota.
Assuntos
Patos/metabolismo , Linguados/metabolismo , Modelos Biológicos , Oligoquetos/metabolismo , Radioisótopos/farmacocinética , Radiometria/métodos , Ratos/metabolismo , Absorção , Animais , Biodiversidade , Carga Corporal (Radioterapia) , Simulação por Computador , Doses de Radiação , Radioisótopos/análise , Eficiência Biológica Relativa , Especificidade da EspécieRESUMO
Under the International Atomic Energy Agency (IAEA)'s EMRAS (Environmental Modelling for Radiation Safety) programme, activity concentrations of (60)Co, (90)Sr, (137)Cs and (3)H in Perch Lake at Atomic Energy of Canada Limited's Chalk River Laboratories site were predicted, in freshwater primary producers, invertebrates, fishes, herpetofauna and mammals using eleven modelling approaches. Comparison of predicted radionuclide concentrations in the different species types with measured values highlighted a number of areas where additional work and understanding is required to improve the predictions of radionuclide transfer. For some species, the differences could be explained by ecological factors such as trophic level or the influence of stable analogues. Model predictions were relatively poor for mammalian species and herpetofauna compared with measured values, partly due to a lack of relevant data. In addition, concentration ratios are sometimes under-predicted when derived from experiments performed under controlled laboratory conditions representative of conditions in other water bodies.
Assuntos
Água Doce/análise , Modelos Biológicos , Plantas , Monitoramento de Radiação/métodos , Radioisótopos/análise , Radioisótopos/farmacocinética , Animais , Canadá , Simulação por Computador , Internacionalidade , Especificidade da EspécieRESUMO
There is now general acknowledgement that there is a requirement to demonstrate that species other than humans are protected from anthropogenic releases of radioactivity. A number of approaches have been developed for estimating the exposure of wildlife and some of these are being used to conduct regulatory assessments. There is a requirement to compare the outputs of such approaches against available data sets to ensure that they are robust and fit for purpose. In this paper we describe the application of seven approaches for predicting the whole-body ((90)Sr, (137)Cs, (241)Am and Pu isotope) activity concentrations and absorbed dose rates for a range of terrestrial species within the Chernobyl exclusion zone. Predictions are compared against available measurement data, including estimates of external dose rate recorded by thermoluminescent dosimeters attached to rodent species. Potential reasons for differences between predictions between the various approaches and the available data are explored.
Assuntos
Acidente Nuclear de Chernobyl , Exposição Ambiental/análise , Exposição Ambiental/estatística & dados numéricos , Modelos Biológicos , Radiometria/estatística & dados numéricos , Radiometria/veterinária , Animais , Simulação por Computador , Internacionalidade , Doses de Radiação , Ucrânia/epidemiologiaRESUMO
Diabetic encephalopathy is characterized by impaired cognitive functions that appear to underlie neuronal damage triggered by glucose driven oxidative stress. Hyperglycemia-induced oxidative stress in diabetic brain may initiate structural and functional changes in synaptosomal membranes. The objective of the present study was to examine the neuroprotective role of N-acetylcysteine (NAC) in hyperglycemia-induced alterations in lipid composition and activity of membrane bound enzymes (Na(+),K(+)-ATPase and Ca(2+)-ATPase) in the rodent model of type 1 diabetes. Male Wistar rats weighing between 180 and 200 g were rendered diabetic by a single injection of streptozotocin (50 mg/kg body weight, i.p.). The diabetic animals were administered NAC (1.4-1.5 g/kg body weight) for eight weeks and lipid composition along with membrane fluidity were determined. A significant increase in lipid peroxidation was observed in cerebral cortex of diabetic rats. NAC administration on the other hand lowered the hyperglycemia-induced lipid peroxidation to near control levels. The increased lipid peroxidation following chronic hyperglycemia was accompanied by a significant increase in the total lipids which can be attributed to increase in the levels of cholesterol, triglycerides and glycolipids. On the contrary phospholipid and ganglioside levels were decreased. Hyperglycemia-induced increase in cholesterol to phospholipid ratio reflected decrease in membrane fluidity. Fluorescence polarization (p) with DPH also confirmed decrease in synaptosomal membrane fluidity that influenced the activity of membrane bound enzymes. An inverse correlation was found between fluorescence polarization with the activities of Na(+),K(+)-ATPase (r(2)=0.416, P<0.05) and Ca(2+) ATPase (r(2)=0.604, P<0.05). NAC was found to significantly improve lipid composition, restore membrane fluidity and activity of membrane bound enzymes. Our results clearly suggest perturbations in lipid composition and membrane fluidity as a major factor in the development of diabetic encephalopathy. Furthermore, NAC administration ameliorated the effect of hyperglycemia on oxidative stress and alterations in lipid composition thereby restoring membrane fluidity and activity of membrane bound enzymes.
Assuntos
Acetilcisteína/farmacologia , Antioxidantes/farmacologia , Hiperglicemia/metabolismo , Membranas Intracelulares/efeitos dos fármacos , Fluidez de Membrana/efeitos dos fármacos , Fármacos Neuroprotetores/farmacologia , Sinaptossomos/efeitos dos fármacos , Animais , Glicemia/metabolismo , ATPases Transportadoras de Cálcio/metabolismo , Córtex Cerebral/química , Diabetes Mellitus Experimental/metabolismo , Membranas Intracelulares/enzimologia , Peroxidação de Lipídeos/efeitos dos fármacos , Lipídeos/análise , Masculino , Ligação Proteica , Ratos , Ratos Wistar , ATPase Trocadora de Sódio-Potássio/metabolismo , Sinaptossomos/enzimologiaRESUMO
The RESRAD-RDD methodology was applied to model the short- and long-term radiation exposures after a hypothetical radiological dispersal device (RDD) event in an urban environment. It was assumed that an RDD event would result in outside surface contamination of the exterior walls and roofs of surrounding buildings, as well as associated paved areas and lawns. The contaminants also might move inside the buildings and deposit on floors and interior walls. Some important input parameters include occupancy factors, building characteristics, and weathering of surface contamination. The modeling results include predicted external dose rates, relative contributions from important surfaces, annual and cumulative doses, and radionuclide concentrations. Potential countermeasures evaluated include grass removal, soil removal, and washing of paved areas.
Assuntos
Planejamento em Desastres/métodos , Recuperação e Remediação Ambiental/métodos , Monitoramento de Radiação/métodos , Proteção Radiológica/métodos , Liberação Nociva de Radioativos , Terrorismo/prevenção & controle , Aerossóis , Poluentes Atmosféricos , Cidades , Arquitetura de Instituições de Saúde , Substâncias Perigosas , Humanos , Modelos TeóricosRESUMO
The Urban Remediation Working Group of the International Atomic Energy Agency's EMRAS (Environmental Modelling for Radiation Safety) program was organized to address issues of remediation assessment modelling for urban areas contaminated with dispersed radionuclides. The present paper describes the second of two modelling exercises. This exercise was based on a hypothetical dispersal of radioactivity in an urban area from a radiological dispersal device, with reference surface contamination at selected sites used as the primary input information. Modelling endpoints for the exercise included radionuclide concentrations and external dose rates at specified locations, contributions to the dose rates from individual surfaces, and annual and cumulative external doses to specified reference individuals. Model predictions were performed for a "no action" situation (with no remedial measures) and for selected countermeasures. The exercise provided an opportunity for comparison of three modelling approaches, as well as a comparison of the predicted effectiveness of various countermeasures in terms of their short-term and long-term effects on predicted doses to humans.
Assuntos
Recuperação e Remediação Ambiental/métodos , Radioatividade , Cidades , Modelos TeóricosRESUMO
A number of models have recently been, or are currently being, developed to enable the assessment of radiation doses from ionising radiation to non-human species. A key component of these models is the ability to predict whole-organism activity concentrations in a wide range of wildlife. In this paper, we compare the whole-organism activity concentrations predicted by eight models participating within the IAEA Environmental Modelling for Radiation Safety programme for a range of radionuclides to terrestrial and freshwater organisms. In many instances, there was considerable variation, ranging over orders of magnitude, between the predictions of the different models. Reasons for this variability (including methodology, data source and data availability) are identified and discussed. The active participation of groups responsible for the development of key models within this exercise is a useful step forward in providing the transparency in methodology and data provenance required for models which are either currently being used for regulatory purposes or which may be used in the future. The work reported in this paper, and supported by other findings, demonstrates that the largest contribution to variability between model predictions is the parameterisation of their transfer components. There is a clear need to focus efforts and provide authoritative compilations of those data which are available.
Assuntos
Ecossistema , Modelos Biológicos , Radiometria/métodos , Compostos Radiofarmacêuticos/análise , Compostos Radiofarmacêuticos/farmacocinética , Animais , Biodiversidade , Simulação por Computador , Humanos , Doses de Radiação , Reprodutibilidade dos Testes , Sensibilidade e EspecificidadeRESUMO
As part of the requirement for terminating the licenses of nuclear power plants or other nuclear facilities, license termination plans or decommissioning plans are submitted by the licensee to the U.S. Nuclear Regulatory Commission (NRC) for review and approval. Decommissioning plans generally refer to the decommissioning of nonreactor facilities, while license termination plans specifically refer to the decommissioning of nuclear reactor facilities. To provide a uniform and consistent review of dose modeling aspects of these plans and to address NRC-wide knowledge management issues, the NRC, in 2006, commissioned Argonne National Laboratory to develop a Web-based training course on reviewing radiological dose assessments for license termination. The course, which had first been developed in 2005 to target specific aspects of the review processes for license termination plans and decommissioning plans, evolved from a live classroom course into a Web-based training course in 2006. The objective of the Web-based training course is to train NRC staff members (who have various relevant job functions and are located at headquarters, regional offices, and site locations) to conduct an effective review of dose modeling in accordance with the latest NRC guidance, including NUREG-1757, Volumes 1 and 2. The exact size of the staff population who will receive the training has not yet been accurately determined but will depend on various factors such as the decommissioning activities at the NRC. This Web-based training course is designed to give NRC staff members modern, flexible access to training. To this end, the course is divided into 16 modules: 9 core modules that deal with basic topics, and 7 advanced modules that deal with complex issues or job-specific topics. The core and advanced modules are tailored to various NRC staff members with different job functions. The Web-based system uses the commercially available software Articulate, which incorporates audio, video, and animation in slide presentations and has glossary, document search, and Internet connectivity features. The training course has been implemented on an NRC system that allows staff members to register, select courses, track records, and self-administer quizzes.
Assuntos
Internet , Licenciamento , Centrais Elétricas , Doses de Radiação , Monitoramento de Radiação/métodos , Proteção Radiológica/métodos , Humanos , Proteção Radiológica/legislação & jurisprudência , Proteção Radiológica/normas , Medição de Risco , Gestão da Segurança , Software , Estados UnidosRESUMO
The Urban Remediation Working Group of the International Atomic Energy Agency's Environmental Modelling for Radiation Safety (EMRAS) programme was established to improve modelling and assessment capabilities for radioactively contaminated urban situations, including the effects of countermeasures. An example of the Working Group's activities is an exercise based on Chernobyl fallout data in Ukraine, which has provided an opportunity to compare predictions among several models and with available measurements, to discuss reasons for discrepancies, and to identify areas where additional information would be helpful.