1,499 research outputs found

    An Introduction to the Chalk Aquifers of Northern Europe

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    We briefly outline the progressive development of approaches to both the characterization and simulation of the hydrogeology of northern European chalk aquifers, which were some of the first in the world to be studied. The volume's scope includes work on water resources and quality, chalk streams and wetland ecosystems, chalks as heat reservoirs for building temperature regulation, sources of groundwater flood risk and impacts of engineering on the subsurface, and diffuse and point-source pollution affecting these aquifers. It excludes hydrocarbon-related studies and those focused on offshore chalk sequences. We briefly outline the current state of knowledge of hydrogeological processes, characterization, assessment and modelling, and the increasingly recognized importance of karst features. The latter were little discussed 20 years ago and are still often neglected. There follows a brief quantitative analysis of publication topics relating to chalk hydrogeology in the scientific literature over the past three decades, which highlights key trends including both the purposes of studies and the methods employed. We present a summary of the topics and contributions within this volume, and conclude by identifying the key issues that need to be addressed in order to ensure the sustainability of our chalk aquifers for the future

    Reminiscence therapy for dementia

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    BACKGROUND: This updated Cochrane Review of reminiscence therapy (RT) for dementia was first published in 1998, and last updated in 2005. RT involves the discussion of memories and past experiences with other people using tangible prompts such as photographs or music to evoke memories and stimulate conversation. RT is implemented widely in a range of settings using a variety of formats. OBJECTIVES: To assess the effects of RT on people living with dementia and their carers, taking into account differences in its implementation, including setting (care home, community) and modality (group, individual). SEARCH METHODS: We searched ALOIS (the Cochrane Dementia and Cognitive Improvement Group's Specialized Register) on 6 April 2017 using the search term 'reminiscence.' SELECTION CRITERIA: We included all randomised controlled trials of RT for dementia in which the duration of the intervention was at least four weeks (or six sessions) and that had a 'no treatment' or passive control group. Outcomes of interest were quality of life (QoL), cognition, communication, behaviour, mood and carer outcomes. DATA COLLECTION AND ANALYSIS: Two authors (LOP and EF) independently extracted data and assessed risk of bias. Where necessary, we contacted study authors for additional information. We pooled data from all sufficiently similar studies reporting on each outcome. We undertook subgroup analysis by setting (community versus care home) and by modality (individual versus group). We used GRADE methods to assess the overall quality of evidence for each outcome. MAIN RESULTS: We included 22 studies involving 1972 people with dementia. Meta-analyses included data from 16 studies (1749 participants). Apart from six studies with risk of selection bias, the overall risk of bias in the studies was low.Overall, moderate quality evidence indicated RT did not have an important effect on QoL immediately after the intervention period compared with no treatment (standardised mean difference (SMD) 0.11, 95% confidence interval (CI) -0.12 to 0.33; I2= 59%; 8 studies; 1060 participants). Inconsistency between studies mainly related to the study setting. There was probably a slight benefit in favour of RT in care homes post-treatment (SMD 0.46, 95% CI 0.18 to 0.75; 3 studies; 193 participants), but little or no difference in QoL in community settings (867 participants from five studies).For cognitive measures, there was high quality evidence for a very small benefit, of doubtful clinical importance, associated with reminiscence at the end of treatment (SMD 0.11, 95% CI 0.00 to 0.23; 14 studies; 1219 participants), but little or no difference at longer-term follow-up. There was a probable slight improvement for individual reminiscence and for care homes when analysed separately, but little or no difference for community settings or for group studies. Nine studies included the widely used Mini-Mental State Examination (MMSE) as a cognitive measure, and, on this scale, there was high quality evidence for an improvement at the end of treatment (mean difference (MD) 1.87 points, 95% CI 0.54 to 3.20; 437 participants). There was a similar effect at longer-term follow-up, but the quality of evidence for this analysis was low (1.8 points, 95% CI -0.06 to 3.65).For communication measures, there may have been a benefit of RT at the end of treatment (SMD -0.51 points, 95% CI -0.97 to -0.05; I2= 62%; negative scores indicated improvement; 6 studies; 249 participants), but there was inconsistency between studies, related to the RT modality. At follow-up, there was probably a slight benefit of RT (SMD -0.49 points, 95% CI -0.77 to -0.21; 4 studies; 204 participants). Effects were uncertain for individual RT, with very low quality evidence available. For reminiscence groups, evidence of moderate quality indicated a probable slight benefit immediately (SMD -0.39, 95% CI -0.71 to -0.06; 4 studies; 153 participants), and at later follow-up. Community participants probably benefited at end of treatment and follow-up. For care home participants, the results were inconsistent between studies and, while there may be an improvement at follow-up, at the end of treatment the evidence quality was very low and effects were uncertain.Other outcome domains examined for people with dementia included mood, functioning in daily activities, agitation/irritability and relationship quality. There were no clear effects in these domains. Individual reminiscence was probably associated with a slight benefit on depression scales, although its clinical importance was uncertain (SMD -0.41, 95% CI -0.76 to -0.06; 4 studies; 131 participants). We found no evidence of any harmful effects on people with dementia.We also looked at outcomes for carers, including stress, mood and quality of relationship with the person with dementia (from the carer's perspective). We found no evidence of effects on carers other than a potential adverse outcome related to carer anxiety at longer-term follow-up, based on two studies that had involved the carer jointly in reminiscence groups with people with dementia. The control group carers were probably slightly less anxious (MD 0.56 points, 95% CI -0.17 to 1.30; 464 participants), but this result is of uncertain clinical importance, and is also consistent with little or no effect. AUTHORS' CONCLUSIONS: The effects of reminiscence interventions are inconsistent, often small in size and can differ considerably across settings and modalities. RT has some positive effects on people with dementia in the domains of QoL, cognition, communication and mood. Care home studies show the widest range of benefits, including QoL, cognition and communication (at follow-up). Individual RT is associated with probable benefits for cognition and mood. Group RT and a community setting are associated with probable improvements in communication. The wide range of RT interventions across studies makes comparisons and evaluation of relative benefits difficult. Treatment protocols are not described in sufficient detail in many publications. There have been welcome improvements in the quality of research on RT since the previous version of this review, although there still remains a need for more randomised controlled trials following clear, detailed treatment protocols, especially allowing the effects of simple and integrative RT to be compared

    Sea-level constraints on the amplitude and source distribution of Meltwater Pulse 1A.

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    During the last deglaciation, sea levels rose as ice sheets retreated. This climate transition was punctuated by periods of more intense melting; the largest and most rapid of these—Meltwater Pulse 1A—occurred about 14,500 years ago, with rates of sea-level rise reaching approximately 4 m per century1, 2, 3. Such rates of rise suggest ice-sheet instability, but the meltwater sources are poorly constrained, thus limiting our understanding of the causes and impacts of the event4, 5, 6, 7. In particular, geophysical modelling studies constrained by tropical sea-level records1, 8, 9 suggest an Antarctic contribution of more than seven metres, whereas most reconstructions10 from Antarctica indicate no substantial change in ice-sheet volume around the time of Meltwater Pulse 1A. Here we use a glacial isostatic adjustment model to reinterpret tropical sea-level reconstructions from Barbados2, the Sunda Shelf3 and Tahiti1. According to our results, global mean sea-level rise during Meltwater Pulse 1A was between 8.6 and 14.6 m (95% probability). As for the melt partitioning, we find an allowable contribution from Antarctica of either 4.1 to 10.0 m or 0 to 6.9 m (95% probability), using two recent estimates11, 12 of the contribution from the North American ice sheets. We conclude that with current geologic constraints, the method applied here is unable to support or refute the possibility of a significant Antarctic contribution to Meltwater Pulse 1A

    Introducing EMMIE: An evidence rating scale to encourage mixed-method crime prevention synthesis reviews

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    Objectives This short report describes the need for, and the development of, a coding system to distil the quality and coverage of systematic reviews of the evidence relating to crime prevention interventions. The starting point for the coding system concerns the evidence needs of policymakers and practitioners. Methods The coding scheme (EMMIE) proposed builds on previous scales that have been developed to assess the probity, coverage and utility of evidence both in health and criminal justice. It also draws on the principles of realist synthesis and review. Results The proposed EMMIE scale identifies five dimensions to which systematic reviews intended to inform crime prevention should speak. These are the Effect of intervention, the identification of the causal Mechanism(s) through which interventions are intended to work, the factors that Moderate their impact, the articulation of practical Implementation issues, and the Economic costs of intervention

    Weak Localization Effect in Superconductors by Radiation Damage

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    Large reductions of the superconducting transition temperature TcT_{c} and the accompanying loss of the thermal electrical resistivity (electron-phonon interaction) due to radiation damage have been observed for several A15 compounds, Chevrel phase and Ternary superconductors, and NbSe2\rm{NbSe_{2}} in the high fluence regime. We examine these behaviors based on the recent theory of weak localization effect in superconductors. We find a good fitting to the experimental data. In particular, weak localization correction to the phonon-mediated interaction is derived from the density correlation function. It is shown that weak localization has a strong influence on both the phonon-mediated interaction and the electron-phonon interaction, which leads to the universal correlation of TcT_{c} and resistance ratio.Comment: 16 pages plus 3 figures, revtex, 76 references, For more information, Plesse see http://www.fen.bilkent.edu.tr/~yjki

    Three-dimensional Noninvasive Monitoring Iodine-131 Uptake in the Thyroid Using a Modified Cerenkov Luminescence Tomography Approach

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    BACKGROUND: Cerenkov luminescence tomography (CLT) provides the three-dimensional (3D) radiopharmaceutical biodistribution in small living animals, which is vital to biomedical imaging. However, existing single-spectral and multispectral methods are not very efficient and effective at reconstructing the distribution of the radionuclide tracer. In this paper, we present a semi-quantitative Cerenkov radiation spectral characteristic-based source reconstruction method named the hybrid spectral CLT, to efficiently reconstruct the radionuclide tracer with both encouraging reconstruction results and less acquisition and image reconstruction time. METHODOLOGY/PRINCIPAL FINDINGS: We constructed the implantation mouse model implanted with a 400 µCi Na(131)I radioactive source and the physiological mouse model received an intravenous tail injection of 400 µCi radiopharmaceutical Iodine-131 (I-131) to validate the performance of the hybrid spectral CLT and compared the reconstruction results, acquisition, and image reconstruction time with that of single-spectral and multispectral CLT. Furthermore, we performed 3D noninvasive monitoring of I-131 uptake in the thyroid and quantified I-131 uptake in vivo using hybrid spectral CLT. Results showed that the reconstruction based on the hybrid spectral CLT was more accurate in localization and quantification than using single-spectral CLT, and was more efficient in the in vivo experiment compared with multispectral CLT. Additionally, 3D visualization of longitudinal observations suggested that the reconstructed energy of I-131 uptake in the thyroid increased with acquisition time and there was a robust correlation between the reconstructed energy versus the gamma ray counts of I-131 (r(2) = 0.8240). The ex vivo biodistribution experiment further confirmed the I-131 uptake in the thyroid for hybrid spectral CLT. CONCLUSIONS/SIGNIFICANCE: Results indicated that hybrid spectral CLT could be potentially used for thyroid imaging to evaluate its function and monitor its treatment for thyroid cancer

    Relative fat oxidation is higher in children than adults

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    Background: Prepubescent children may oxidize fatty acids more readily than adults. Therefore, dietary fat needs would be higher for children compared with adults. The dietary fat recommendations are higher for children 4 to 18 yrs (i.e., 25 to 35% of energy) compared with adults (i.e., 20 to 35% of energy). Despite this, many parents and children restrict dietary fat for health reasons. Methods: This study assessed whether rates of fat oxidation are similar between prepubescent children and adults. Ten children (8.7 ± 1.4 yr, 33 ± 13 kg mean ± SD) in Tanner stage 1 and 10 adults (41.6 ± 8 yr, 74 ± 13 kg) were fed a weight maintenance diet for three days to maintain body weight and to establish a consistent background for metabolic rate measurements (all foods provided). Metabolic rate was measured on three separate occasions before and immediately after breakfast and for 9 hrs using a hood system (twice) or a room calorimeter (once) where continuous metabolic measurements were taken. Results: During all three sessions whole body fat oxidation was higher in children (lower RQ) compared to adults (mean RQ= 0.84 ± .016 for children and 0.87 ± .02, for adults, p < 0.02). Although, total grams of fat oxidized was similar in children (62.7 ± 20 g/24 hrs) compared to adults (51.4 ± 19 g/24 hrs), the grams of fat oxidized relative to calorie expenditure was higher in children (0.047 ± .01 g/kcal, compared to adults (0.032 ± .01 p < 0.02). Females oxidized more fat relative to calorie expenditure than males of a similar age. A two way ANOVA showed no interaction between gender and age in terms of fax oxidation. Conclusion: These data suggest that fat oxidation relative to total calorie expenditure is higher in prepubescent children than in adults. Consistent with current dietary guidelines, a moderate fat diet is appropriate for children within the context of a diet that meets their energy and nutrient needs. Originally published Nutrition Journal, Vol. 6, No. 19, Aug 200

    Ethanol Distribution, Dispensing, and Use: Analysis of a Portion of the Biomass-to-Biofuels Supply Chain Using System Dynamics

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    The Energy Independence and Security Act of 2007 targets use of 36 billion gallons of biofuels per year by 2022. Achieving this may require substantial changes to current transportation fuel systems for distribution, dispensing, and use in vehicles. The U.S. Department of Energy and the National Renewable Energy Laboratory designed a system dynamics approach to help focus government action by determining what supply chain changes would have the greatest potential to accelerate biofuels deployment. The National Renewable Energy Laboratory developed the Biomass Scenario Model, a system dynamics model which represents the primary system effects and dependencies in the biomass-to-biofuels supply chain. The model provides a framework for developing scenarios and conducting biofuels policy analysis. This paper focuses on the downstream portion of the supply chain–represented in the distribution logistics, dispensing station, and fuel utilization, and vehicle modules of the Biomass Scenario Model. This model initially focused on ethanol, but has since been expanded to include other biofuels. Some portions of this system are represented dynamically with major interactions and feedbacks, especially those related to a dispensing station owner’s decision whether to offer ethanol fuel and a consumer’s choice whether to purchase that fuel. Other portions of the system are modeled with little or no dynamics; the vehicle choices of consumers are represented as discrete scenarios. This paper explores conditions needed to sustain an ethanol fuel market and identifies implications of these findings for program and policy goals. A large, economically sustainable ethanol fuel market (or other biofuel market) requires low end-user fuel price relative to gasoline and sufficient producer payment, which are difficult to achieve simultaneously. Other requirements (different for ethanol vs. other biofuel markets) include the need for infrastructure for distribution and dispensing and widespread use of high ethanol blends in flexible-fuel vehicles

    Peroxisome Proliferator-Activated Receptor alpha (PPAR alpha) down-regulation in cystic fibrosis lymphocytes

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    Background: PPARs exhibit anti-inflammatory capacities and are potential modulators of the inflammatory response. We hypothesized that their expression and/or function may be altered in cystic fibrosis (CF), a disorder characterized by an excessive host inflammatory response. Methods: PPARα, β and γ mRNA levels were measured in peripheral blood cells of CF patients and healthy subjects via RT-PCR. PPARα protein expression and subcellular localization was determined via western blot and immunofluorescence, respectively. The activity of PPARα was analyzed by gel shift assay. Results: In lymphocytes, the expression of PPARα mRNA, but not of PPARβ, was reduced (-37%; p < 0.002) in CF patients compared with healthy persons and was therefore further analyzed. A similar reduction of PPARα was observed at protein level (-26%; p < 0.05). The transcription factor was mainly expressed in the cytosol of lymphocytes, with low expression in the nucleus. Moreover, DNA binding activity of the transcription factor was 36% less in lymphocytes of patients (p < 0.01). For PPARα and PPARβ mRNA expression in monocytes and neutrophils, no significant differences were observed between CF patients and healthy persons. In all cells, PPARγ mRNA levels were below the detection limit. Conclusion: Lymphocytes are important regulators of the inflammatory response by releasing cytokines and antibodies. The diminished lymphocytic expression and activity of PPARα may therefore contribute to the inflammatory processes that are observed in CF
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