10,948 research outputs found
A Burst-by-Burst Adaptive Joint-Detection Based CDMA Speech Transceiver
No full textA burst-by-burst adaptive speech transceiver is proposed, which can drop its source coding rate and speech quality under transceiver control in order to invoke a more error resilient modem mode amongst less favourable channel conditions. The novel, high-quality, Adaptive Multi-Rate (AMR) speech codec [5], operated at bit rates of 4.75 and 10.2 kbps and combined with sourcesensitivity-matched Redundant Residue Number Systems (RRNS) based channel codes. Burst-by-burst adaptive Joint-Detection based Code-Division Multiple Access (JDCDMA) is used for transmitting the dual-rate bitstream generated by the AMR speech codec
5-ht inhibition of rat insulin 2 promoter cre recombinase transgene and proopiomelanocortin neuron excitability in the mouse arcuate nucleus
No full textA number of anti-obesity agents have been developed that enhance hypothalamic 5-HT transmission. Various studies have demonstrated that arcuate neurons, which express proopiomelanocortin peptides (POMC neurons), and neuropeptide Y with agouti-related protein (NPY/AgRP) neurons, are components of the hypothalamic circuits responsible for energy homeostasis. An additional arcuate neuron population, rat insulin 2 promoter Cre recombinase transgene (RIPCre) neurons, has recently been implicated in hypothalamic melanocortin circuits involved in energy balance. It is currently unclear how 5-HT modifies neuron excitability in these local arcuate neuronal circuits. We show that 5-HT alters the excitability of the majority of mouse arcuate RIPCre neurons, by either hyperpolarization and inhibition or depolarization and excitation. RIPCre neurons sensitive to 5-HT, predominantly exhibit hyperpolarization and pharmacological studies indicate that inhibition of neuronal firing is likely to be through 5-HT1F receptors increasing current through a voltage-dependent potassium conductance. Indeed, 5-HT1F receptor immunoreactivity co-localizes with RIPCre green fluorescent protein expression. A minority population of POMC neurons also respond to 5-HT by hyperpolarization, and this appears to be mediated by the same receptor-channel mechanism. As neither POMC nor RIPCre neuronal populations display a common electrical response to 5-HT, this may indicate that sub-divisions of POMC and RIPCre neurons exist, perhaps serving different outputs. (C) 2009 IBRO. Published by Elsevier Ltd. All rights reserved.</p
"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
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
Hybrid method for natural frequency extraction: Performance improvement using Newton-Raphson method
No full textIt is shown how it is possible to extract more accurate natural frequencies by combining the existing natural frequency extraction methods with a numerical root finding procedure. An application of this hybrid method to a simulated transient response is demonstrated to show the superiority of this hybrid method over the original natural frequency extraction methods which do not use numerical root search procedures.X114sciescopu
How does proximity to crime influence people's perception of safety?
No full textIndividuals may put themselves at risk of criminal victimisation through a misguided sense of safety born from the optimistic notion that crime happens “elsewhere”. Despite the analogous
nature of fear and perceived safety, the latter has received far less research attention within the criminological literature. As perceptions of safety are guided by cognitive appraisals of the threat a danger poses, the present study aimed to investigate whether crimes that occur in nearby locations affect perceptions of safety more so than those that occur further away, due to the proximity of the danger or threat thereof.
Respondents were given a number of fictitious scenarios within which a crime was presented as having occurred at one of four locations, ranging in distance from the respondents’ hometown (i.e. the independent variable). The respondents rated each scenario in terms of its seriousness, how safe they would perceive themselves to be following the news of the crimes and how likely they would be to engage in precautionary measures following the crimes (i.e. the dependent variables). The relationship between crime seriousness, perceived safety and a numberof prominent sociodemographic factors that have emerged from the fear of crime literature were also examined.
Proximate crimes were found to produce lower perceptions of safety; higher crime
seriousness ratings; and greater likelihood of engaging in reactive behaviours than distant crimes, as hypothesised. It was found that young people, females and those who get most of their crime information from local news sources tended to report lower safety perceptions, although several findings were inconsistent with previous research. Possible explanations and implications of the findings are discussed and an argument is made for the importance of increasing individuals’
knowledge and awareness of victimisation risks, rather than attempting to reduce fear of crime as
has been a major research focus to date
Esimiestyön nykytila-analyysi: Case: HT Laser Oy Keuruu
No full textOpinnäytetyön tavoitteena oli tutkia esimiestyön nykytilaa toimeksiantajan Keuruun tuotantoyksikössä, missä tuotanto on kasvanut paljon viimeisen kahden vuoden aikana. Esimiestyön nykytilan selvittämisen lisäksi selvitettiin mahdollisia kehitysehdotuksia, miten esimiestyön kehittyminen tulevaisuudessa voitaisiin mahdollistaa. Tutkimustulosten avulla pyrittiin lisäämään toimeksiantajan tietoisuutta esimiestyön sisällöstä ja mitä esimiesosaamista yksiköstä löytyy tutkimusta tehtäessä. Opinnäytetyön toimeksiantaja oli HT Laser Oy, joka on kotimainen metallialan yritys.
Tutkimus toteutettiin kvalitatiivisella tutkimusotteella. Tutkimus toteutettiin yksilöteemahaastatteluilla toimeksiantajan tiloissa. Haastatteluihin osallistui kuusi yksikön kymmenestä esimiehestä. Haastattelut pidettiin vuoden 2018 loka- ja marraskuun aikana.
Tutkimustuloksista selvisi, että yksikön esimiestyön sisältö ei ole juurikaan muuttunut tuotannon kasvusta huolimatta. Yksikössä työskentelee motivoituneita ja kehittymishaluisia esimiehiä, jotka johtavat tuotantoa vahvan tuotantoon liittyvän substanssiosaamisen avulla. Esimiesten työ keskittyy lähinnä tuotannon johtamiseen ja kehittämiseen sekä tehokkuuden ylläpitämiseen. Monet yksikön esimiestyössä esiintyvät haasteet ja puutteet johtuvat siitä, että esimiestyön sisältöä ja periaatteita ei ole määritetty. Määrittämättömät kokonaisuudet aiheuttavat epäselvyyttä ja käsitykset jäävät yksilöiden tasolle.
Saatujen tulosten pohjalta jatkotutkimuksena voisi toteuttaa yksikön esimiestyötä ammatillistavan ja vakiinnuttavan dokumentin laatimisen, jossa luodaan raamit organisaation edellyttämälle esimiestyölle. Dokumentti voisi olla laajempi koonnos koko organisaation toiminnan periaatteista tai nimenomaan esimiehille suunnattu dokumentti, jossa määritellään esimiestyön periaatteet ja työtehtävät.The aim of the thesis was to examine the current state of managerial work in one of the client’s factories located in Keuruu. The production volume of the factory has increased significantly in the past two years. In addition to examining the current state of managerial work, potential development proposals were mapped out. The aim was to increase the client’s knowledge regarding the contents of managerial work and what leadership skills could be detected in the factory during the time of the study. The client of this study was HT Laser Oy which is a Finnish company working in the metal industry.
The study was executed by using qualitative research methods. The study consisted of individual theme interviews which were carried out for six out of the ten managers working in the factory. The interviews were held during October and November of 2018.
The research results showed that the contents of managerial work in the factory have not experienced major changes despite the increase in production volume. The managers of the factory were motivated to develop their managing skills. Production lines ware managed by having a high level of practical know-how regarding the production. Management was focused on production management and development and maintaining production efficiency. Many of the detected challenges were a consequence of the lack of definitions regarding managerial work. Undefined aspects of management caused ambiguity and thus perceptions were created and maintained on an individual’s level.
Based on the results of the study, further studies could focus on developing a document that would define a frame for managerial work based on requirements set by the organization. The document would professionalize and solidify managerial work in the organization. The document could be a compilation of the overall principles of the whole organization or a document aimed strictly towards the managers which would specifically define the principles and job functions of managerial work
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
Constitutively active 5-HT receptors: An explanation of how 5-HT antagonists inhibit gut motility in species where 5-HT is not a enteric neurotransmitter ?
No full textAntagonists of 5-Hydroxytryptamine (5-HT) receptors are well known to inhibit gastrointestinal (GI)-motility and transit in a variety of mammals, including humans. Originally, these observations had been interpreted by many investigators (including us) as evidence that endogenous 5-HT plays a major role in GI motility. This seemed a logical assumption. However, the story changed dramatically after recent studies revealed that 5-HT antagonists still blocked major GI motility patterns (peristalsis and colonic migrating motor complexes) in segments of intestine depleted of all 5-HT. Then, these results were further supported by Dr. Gershons’ laboratory, which showed that genetic deletion of all genes that synthesizes 5-HT had minor, or no inhibitory effects on GI transit in vivo. If 5-HT was essential for GI motility patterns and transit, then one would expect major disruptions in motility and transit when 5-HT synthesis was genetically ablated. This does not occur. The inhibitory effects of 5-HT antagonists on GI motility clearly occur independently of any 5-HT in the gut. Evidence now suggests that 5-HT antagonists act on 5-HT receptors in the gut which are constitutively active, and don’t require 5-HT for their activation. This would explain a long-standing mystery of how 5-HT antagonists inhibit gut motility in species like mice, rats and humans where 5-HT is not an enteric neurotransmitter. Studies are now increasingly demonstrating that the presence of a neurochemical in enteric neurons does not mean they function as neurotransmitters. Caution should be exercised when interpreting any inhibitory effects of 5-HT antagonists on GI motility
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
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