2,433 research outputs found
Validating an American scale in Hong Kong: the Center for Epidemiological Studies of Depression Scale (CESD)
No full textThe construct validity of a Chinese-language version of the Center for Epidemiological Studies Depression Scale (CES-D; Radloff, 1977) was tested on a sample of 138 Hong Kong Chinese married couples. Confirmatory factor analysis identified 2 factors: (a) depressive symptom factors and (b) interpersonal problem factors. Those factors attained convergent, discriminant, and structural validity when evaluated against social desirability. The CES-D also manifested nomological validity in terms of its significant relationships with measures of life satisfaction and stressful life events
Risk analysis of High-Temperature Aquifer Thermal Energy Storage (HT-ATES)
No full textThe storage of heat in aquifers, also referred to as Aquifer Thermal Energy Storage (ATES), bears a high potential to bridge the seasonal gap between periods of highest thermal energy demand and supply. With storage temperatures higher than 50 °C, High-Temperature (HT) ATES is capable to facilitate the integration of (non-)renewable heat sources into complex energy systems. While the complexity of ATES technology is positively correlated to the required storage temperature, HT-ATES faces multidisciplinary challenges and risks impeding a rapid market uptake worldwide. Therefore, the aim of this study is to provide an overview and analysis of these risks of HT-ATES to facilitate global technology adoption. Risk are identified considering experiences of past HT-ATES projects and analyzed by ATES and geothermal energy experts. An online survey among 38 international experts revealed that technical risks are expected to be less critical than legal, social and organizational risks. This is confirmed by the lessons learned from past HT-ATES projects, where high heat recovery values were achieved, and technical feasibility was demonstrated. Although HT-ATES is less flexible than competing technologies such as pits or buffer tanks, the main problems encountered are attributed to a loss of the heat source and fluctuating or decreasing heating demands. Considering that a HT-ATES system has a lifetime of more than 30 years, it is crucial to develop energy concepts which take into account the conditions both for heat sources and heat sinks. Finally, a site-specific risk analysis for HT-ATES in the city of Hamburg revealed that some risks strongly depend on local boundary conditions. A project-specific risk management is therefore indispensable and should be addressed in future research and project developments.Accepted Author ManuscriptWater Resource
Improving identification of HT-ATES performance drivers and -barriers
No full textHigh temperature aquifer thermal energy storage (HT-ATES) can potentially solve the mismatch between heat supply and demand. It can provide a large scale seasonal heat storage solution. Thereby it enables an increase in full load hours of the base heat source, which can benefit project performance on both costs and emissions. However, the limited number of successful pilot projects indicates the technology has not escaped its state of infancy. There is a gap from concept to implementation, which is signified by the disagreement of experts on performance drivers and barriers of HT-ATES. This research aims to narrow the described knowledge gap, by improving identification of HT-ATES performance drivers and barriers. Thereby it strives to improve decision making of HT-ATES implementation, and further enhance future HT-ATES application in heating projects. The broad scope of research demands both a diagnostic and design-orientated approach, and fits seamlessly with a multi-criteria decision analysis. The analysis entails the stages of creating, evaluating, comparing and ranking of case-specific scenarios. Parametric variation changes the conditions for HT-ATES implementation across the scenarios. A simulation model is developed and connected to a groundwater model to apply the parametric variation, to create the different scenarios, and consequently to produce the quantitative information for further evaluation. During the stages of creating, evaluating, comparing and ranking, the methodology systematically produces new results on the opportunities and risks introduced by HT-ATES, and additionally on the HT-ATES performance drivers and barriers. The results show that HT-ATES enables the opportunity of improving project performance with respect to the internal rate of return and emissions. Groundwater impact remains the greatest risk, but it can be minimised with smart decision making. To support the decision maker and to overcome the risk of groundwater impact, the research proposes several performance-enhancing, non-explicit guidelines. The guidelines focus on realising an HT-ATES implementation, where project performance with respect to internal rate of return, emissions and groundwater impact are balanced. Thereby they explain the major HT-ATES performance drivers and barriers. The guidelines are summarised below. The decision maker is recommended to .. 1. .. minimise the uncertainty, through thorough subsurface characterization before implementation. Secondly, to focus on aquifers with a minimum depth of 200 [m] and a minimum hydraulic conductivity of 5 [m/d] 2. .. assure network return temperatures during peak demand are below expected storage temperatures 3. .. not consider project life-times exceeding 20 years 4. .. assure yearly maximum base source heat production is always lower than yearly consumer heat demand 5. .. to strive for a flat demand curve and apply peak-shaving, by means of, for example, variable heat prices Currently, the guidelines have the purpose of giving direction to the decision maker, but they will become more explicit once the methodology is improved, and the uncertainty and number of assumptions in the model is decreased.Electrical Engineering | Sustainable Energy Technolog
Transforming Ates To Ht-Ates, Insights From Dutch Pilot Project
No full textAquifer Thermal Energy Storage (ATES) systems combined with a heat pump save energy for space heating and cooling of buildings. In most countries the temperature of the stored heat is allowed up to 25-30°C. However, when heat is available at higher temperatures (e.g. waste heat, solar heat), it is more efficient to store higher temperatures because that improves heat pump performance or makes it unnecessary. Therefore, interest in HT-ATES development is growing. Next to developing new HT-ATES projects, there is also a large potential for additional energy savings by transforming ‘regular’ low-temperature LT-ATES systems to a HT-ATES. Such a transformation is tested for a greenhouse system in the Netherlands. This greenhouse has a LT-ATES system operational since 2012, and from 2015 onwards heat is stored in the warm well at temperatures up to 45°C. In this HT-ATES transformation pilot, water quality parameters are closely monitored as well as temperature distribution in the subsurface (using DTS). Together with the operators, the results from the ATES monitoring are used to continuously improve system performance. Numerical groundwater and heat flow simulations of actual and expected well pumping data are used to evaluate how well operation can be optimized. In this paper, the optimization using monitoring results and simulations is discussed as well as general and site specific lessons/conclusions for such transformations.Water Resource
"Put your own house in order first": local perceptions of EU influence on Romani integration policies in the Czech Republic
No full textThis article examines the influence of the European Union (EU) on the development and implementation of Romani integration policy in the Czech Republic from the perspective of those responsible for policy delivery. Based on analysis of key policy documents and research conducted in the Czech Republic, this article first examines how Romani integration became a more important issue during membership negotiations and then discusses how the criticism of the European Commission's Regular Reports was received by those responsible for implementing pro-Romani policies. Finally, the paper assesses how the status of full EU membership has impacted on integration policy. The article concludes that while funding for Romani integration projects has benefitted some groups, the overall impression of the EU is of a remote institution, quick to criticise and unwilling to practise what it preaches
Metabolic and serotonergic modulation of hypothalamic arcuate nucleus neurones in vitro
No full text1. The effects of glucose on the electrophysiological properties of rat hypothalamic arcuate nucleus (ARC) neurones were investigated. Neurones were recorded in 10 mM (hyperglycaemic) and 2 mM (euglycaemic) glucose-containing aCSF. The major findings were that input resistance increased in 10 mM glucose, there was an increase in the activity of neurones in 2 mM glucose and there were a greater percentage of neurones expressing lh in 10 mM glucose. Subthreshold active conductances were differentially expressed in ARC neurones including: anomalous inward rectification Q. ), time- and voltage-dependent inward rectification 00, A-like transient outward rectification (IA) and T-type calcium-like conductance. Characterisation of the differential expression of these conductances may represent one way of functionally classifying ARC neurones.
2. Whole-cell patch clamp recording techniques were used in isolated hypothalamic brain slice preparations to investigate the effects of 5-HT on ARC neurones. Bath application of 5-HT induced a membrane depolarisation in a sub-population of ARC neurones (30%), a response that persisted in the presence of TTX indicating a direct effect. 5-HT excited ARC neurones through three potential mechanisms: closure of one or more resting potassium conductances; activation of a non-selective cation channel, or a combination of the two; or activation of a pump in the membrane. This response was mediated through the 5-HT2A. 5-HT2B and/or 5-HT2C receptors revealed using a range of 5-HT receptor agonists and antagonists. 5-HT was shown to excite CART-expressing neurones suggesting an anorexigenic role for 5-HT, via 5-HT2 receptors at the level of the ARC.
3.5-HT induced a membrane hyperpolarisation in a sub-population of ARC neurones (37%). The 5-HT-induced hyperpolarisation persisted in the presence of TTX indicating a direct effect on ARC neurones. 5-HT inhibited ARC neurones most likely through the activation of one or more potassium conductances,including an inwardly rectifying potassium conductance. Potential roles for 5-HTIA, 5-HTIB and 5-HT7 receptors were suggested from studies utilising 5-HT receptor agonists and antagonists. 5-HT inhibited orexigenic NPY/AgRP neurones, identified by their response to ghrelin and by their electrophysiological properties, suggesting an anorexigenic role for 5-HT, acting via 5-HTI and 5-HT7 receptors on NPY/AgRP neurones at the level of the ARC.
4. The effects of feeding-related signals on hypothalamic neuropeptide expression were investigated using real-time-PCR. A new protocol measuring gene expression from hypothalamic explants was developed. Effects of GABA and AMPA on c-fos expression were investigated and subsequent studies showed leptin and glucose modulated the expression of NPY, POMC and AgRP, in fed and fasted animals. Further work is required to validate this novel approach to studying the central control of energy balance
Hydrogen sulfide activates TRPA1 and releases 5-HT from epithelioid cells of the chicken thoracic aorta
No full textEpithelioid cells in the chicken thoracic aorta are chemoreceptor cells that release 5-HT in response to hypoxia. It is likely that these cells play a role in chemoreception similar to that of glomus cells in the carotid bodies of mammals. Recently, H2S was reported to be a key mediator of carotid glomus cell responses to hypoxia. The aim of the present study was to reveal the mechanism of action of H2S on 5-HT outflow from chemoreceptor cells in the chicken thoracic aorta. The 5-HT outflow induced by NaHS, an H2S donor, and Na2S3, a polysulfide, was measured by using a HPLC equipped with an electrochemical detector. NaHS (0.3-3 mM) caused a concentration-dependent increase in 5-HT outflow, which was significantly inhibited by the removal of extracellular Ca2+. outflow induced by NaHS (0.3 mM) was also significantly inhibited by voltage-dependent L- and N-type Ca2+ channel blockers and a selective TRPA1 channel blocker. Cinnamaldehyde, a TRPA1 agonist, mimicked the secretory response to H2S. 5-HT outflow induced by Na2S3 (10 M) was also inhibited by the TRPA1 channel blocker. Furthermore, the expression of TRPA1 was localized to 5-HT-containing chemoreceptor cells in the aortic wall. These findings suggest that the activation of TRPA1 and voltage-dependent Ca2+ channels is involved in H2S-evoked 5-HT release from chemoreceptor cells in the chicken aorta. (C) 2016 Elsevier Inc. All rights reserved
Neurexins in serotonergic neurons regulate serotonin transmission and complex mouse behaviors [preprint]
No full textThis article is a preprint. Preprints are preliminary reports of work that have not been certified by peer review.Extensive serotonin (5-HT) innervation throughout the brain corroborates 5-HT’s modulatory role in numerous cognitive activities. Volume transmission is the major mode for 5-HT transmission but mechanisms underlying 5-HT signaling are still largely unknown. Abnormal brain 5-HT levels and function have been implicated in autism spectrum disorder (ASD). Neurexin (Nrxn) genes encode presynaptic cell adhesion molecules important for the regulation of synaptic neurotransmitter release, notably glutamatergic and GABAergic transmission. Mutations in Nrxn genes are associated with neurodevelopmental disorders including ASD. However, the role of Nrxn genes in the 5-HT system is poorly understood. Here, we generated a mouse model with all three Nrxn genes disrupted specifically in 5-HT neurons to study how Nrxns affect 5-HT transmission. Loss of Nrxns in 5-HT neurons impaired 5-HT release in the dorsal raphe nucleus and dorsal hippocampus and decreased serotonin transporter distribution in specific brain areas. Furthermore, 5-HT neuron-specific Nrxn knockout reduced sociability and increased depressive-like behavior. Our results highlight functional roles for Nrxns in 5-HT neurotransmission and the execution of complex behaviors.MD/Ph
High-Temperature Aquifer Thermal Energy Storage (HT-ATES) system for research development and demonstration on the TU Delft campus
No full textAt present, over half of all primary energy used in Europe is used for heating and cooling. Therefore, decarbonizing the heating supply is essential to achieve climate targets. Underground thermal energy storage is a key enabling technology for the energy transition to buffer the large seasonal mismatch between thermal energy demand and sustainable thermal energy production capabilities. In Delft, a High-Temperature Aquifer Thermal Energy Storage (HT-ATES) system will be installed at the campus of Delft University of Technology (TU Delft). It will be integrated in the wider heating system on and around the TU Delft campus, which itself is undergoing a transformation to optimally supply sustainable thermal energy. The district heating network will be extended and utilize the thermal energy from a geothermal doublet producing heat at around 75-80°C with a flow rate of ~350m3/hr. Excess energy produced by the geothermal well in summer will be stored in the HT-ATES system, and will be utilised when demand exceeds production throughout the winter. The HT-ATES system will comprise of 7 wells (3 hot wells of 80°C and 4 warm wells of 50°C) to a depth of approximately 200m, with storage in an unconsolidated sedimentary aquifer between 160-200m depth. It is designed so that the instantaneous excess power from the geothermal project can be stored and demand from the district heating network be extracted from the system.The HT-ATES system at TU Delft is partially funded by local stakeholders and the European commission within the PUSH-IT project and has two primary goals: (i) to reduce carbon emissions on TU Delft campus , and (ii) to create a unique demonstration, education and research infrastructure. The complexity of a HT-ATES requires innovative solutions during the entire system life cycle. The scientific programme that is initially planned within the project is therefore focusing on various research fields and includes:- Characterisation of the subsurface formations including mechanical, hydraulic, thermal, and chemical properties.- Evaluation and monitoring of the biological conditions and microbial diversity, and potential impact on water quality.- Innovations in drilling and completion, monitoring and performance.- Quantification of the system performance and system impact during multiple storage cycles and the full lifecycle of the HT-ATES. This will include extensively monitoring temperature distribution and water quality in the subsurface to characterise behaviour and improve models.- Demonstrate and develop the implementation of HT-ATES in an urban setting, including control of the system in the built-environment and transforming the conventional heat network to a future-proof heat network.- To allow access to other universities or institutions with active programmes in the field of Geothermal Science and Engineering to jointly carry out research and perform experiments.-Societal engagement and legal evaluation for improving the just energy transition.Geo-engineeringWater Resource
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