953 research outputs found
Prospects for Assessing Enhanced Geothermal System (EGS) Basement Rock Flow Stimulation by Wellbore Temperature Data
We use Matlab 3D finite element fluid flow/transport modelling to simulate localized wellbore temperature events of order 0.05â0.1 °C logged in Fennoscandia basement rock at ~1.5 km depths. The temperature events are approximated as steady-state heat transport due to fluid draining from the crust into the wellbore via naturally occurring fracture-connectivity structures. Flow simulation is based on the empirics of spatially-correlated fracture-connectivity fluid flow widely attested by well-log, well-core, and well-production data. Matching model wellbore-centric radial temperature profiles to a 2D analytic expression for steady-state radial heat transport with Peclet number Pe ⥠r0Ïv0/D (r0 = wellbore radius, v0 = Darcy velocity at r0, Ï = ambient porosity, D = rock-water thermal diffusivity), gives Pe ~ 10â15 for fracture-connectivity flow intersecting the well, and Pe ~ 0 for ambient crust. Darcy flow for model Pe ~ 10 at radius ~10 m from the wellbore gives permeability estimate Îș ~ 0.02 Darcy for flow driven by differential fluid pressure between least principal crustal stress pore pressure and hydrostatic wellbore pressure. Model temperature event flow permeability Îșm ~ 0.02 Darcy is related to well-core ambient permeability Îș ~ 1 ”Darcy by empirical poroperm relation Îșm ~ Îș exp(αmÏ) for Ï ~ 0.01 and αm ~ 1000. Our modelling of OTN1 wellbore temperature events helps assess the prospect of reactivating fossilized fracture-connectivity flow for EGS permeability stimulation of basement rock.Peer reviewe
Microeconomic Evidence on Price-Setting
The last decade has seen a burst of micro price studies. Many studies analyze data underlying national CPIs and PPIs. Others focus on more granular sub-national grocery store data. We review these studies with an eye toward the role of price setting in business cycles. We summarize with ten stylized facts: Prices change at least once a year, with temporary price discounts and product turnover often playing an important role. After excluding many short-lived prices, prices change closer to once a year. The frequency of price changes differs widely across goods, however, with more cyclical goods exhibiting greater price flexibility. The timing of price changes is little synchronized across sellers. The hazard (and size) of price changes does not increase with the age of the price. The cross-sectional distribution of price changes is thick-tailed, but contains many small price changes too. Finally, strong linkages exist between price changes and wage changes.
Combined Oxides of Iron, Manganese and Silica as Oxygen Carriers for Chemical-Looping Combustion
Spray-dried particles with the chemical compositions of Fe0.66Mn1.33SiO3 and FeMnSiO3 have been examined as oxygen carrier materials for chemical-looping combustion. The performance of the materials was examined in oxygen release experiments and during fuel operation with natural gas and syngas. The experiments were carried out in a fluidized-bed chemical-looping reactor system designed for a thermal power of 300 W. The reactor system includes an air reactor and a fuel reactor, as well as loop seals and means for circulation of the oxygen carrier particles. Both materials were able to release gas phase oxygen in inert atmosphere at temperatures between 800-950°C, and with approximately equal oxygen concentrations. Fe0.66Mn1.33SiO3 provided higher conversion of natural gas as compared to FeMnSiO3 and the fuel conversion increased with temperature for both materials. During natural gas operation with Fe0.66Mn1.33SiO3 the conversion reached 100% at around 950°C with a fuel reactor inventory of 235 kg/MW. The fuel conversion was improved when the solids inventory was increased; this improvement could especially be observed for FeMnSiO3 as the fuel conversion was lower for this material. Fe0.66Mn1.33SiO3 provided higher fuel conversion than FeMnSiO3 also when syngas was used as fuel. The fuel conversion increased with temperature for both materials and full conversion was reached above 800°C with a fuel reactor inventory of 225 kg/MW for Fe0.66Mn1.33SiO3, while FeMnSiO3 was incapable of providing full conversion. A rather large elutriation of fines and a significant change in particle size distribution could be observed during operation for both materials.
Both materials could work as oxygen carrier for chemical-looping with oxygen uncoupling. Fe0.66Mn1.33SiO3 would be preferred as it has higher conversion of both syngas and natural gas, but the attrition behavior of the material would need to be further investigated
PSYKOEDUKATION I RĂDE KORS â fra mentale skemaer til handling i fĂŠllesskaber
Denne artikel beskriver forskellige psykoedukative forlÞb for traumatiserede asylansÞgere i RÞde Kors Centre i Danmark. Gennem observation, interviews og lÊsning af evalueringsrapporter blev forlÞbene undersÞgt med henblik pÄ en beskrivelse af deres praksis. Artiklen viser, at resultaterne af forlÞbene bedre kan forstÄs i en community-psykologisk end i en kognitiv teoriramme. De alternative fortÊllinger, der blev skabt i interventionsrummet, kan kun blive effektive i dagliglivet, hvis den praktiske og sociale kontekst for dette inkluderes i forlÞbet. Deltagerne fortalte, at de fik mest ud af forlÞbene, nÄr disse praktisk og socialt forandrede deres muligheder i fÊllesskabet, sÄvel pÄ centret som udenfor, gennem opbygning af social kontakter og gennem Þgede praktiske fÊrdigheder. At kunne pÄvirke udformningen af dagligdagen, sammen med de Þvrige deltagere i denne, blev vurderet som et positivt udkomme af de bedste af programmerne
The NMDA antagonist memantine affects training induced motor cortex plasticity â a study using transcranial magnetic stimulation [ISRCTN65784760]
BACKGROUND: Training of a repetitive synchronised movement of two limb muscles leads to short-term plastic changes in the primary motor cortex, which can be assessed by transcranial magnetic stimulation (TMS) mapping. We used this paradigm to study the effect of memantine, a NDMA antagonist, on short-term motor cortex plasticity in 20 healthy human subjects, and we were especially interested in possible differential effects of different treatment regimens. In a randomised double-blinded cross over study design we therefore administered placebo or memantine either as a single dosage or as an ascending dosage over 8 days. Before and after one hour of motor training, which consisted of a repetitive co-contraction of the abductor pollicis brevis (APB) and the deltoid muscle, we assessed the motor output map of the APB muscle by TMS under the different conditions. RESULTS: We found a significant medial shift of the APB motor output map after training in the placebo condition, indicating training-induced short-term plastic changes in the motor cortex. A single dosage of memantine had no significant effect on this training-induced plasticity, whereas memantine administered in an ascending dosage over 8 days was able to block the cortical effect of the motor training. The memantine serum levels after 8 days were markedly higher than the serum levels after a single dosage of memantine, but there was no individual correlation between the shift of the motor output map and the memantine serum level. Besides, repeated administration of a low memantine dosage also led to an effective blockade of training-induced cortical plasticity in spite of serum levels comparable to those reached after single dose administration, suggesting that the repeated administration was more important for the blocking effect than the memantine serum levels. CONCLUSION: We conclude that the NMDA-antagonist memantine is able to block training-induced motor cortex plasticity when administered over 8 days, but not after administration of a single dose. This differential effect might be mainly due to the prolonged action of memantine at the NMDA receptor. These findings must be considered if clinical studies are designed, which aim at evaluating the potency of memantine to prevent "maladaptive" plasticity, e.g. after limb amputation
PSYKOLOGISKT TRAUMA â UR ETT EKOLOGISKT COMMUNITY PSYKOLOGISKT PERSPEKTIV
Artiklen prĂŠsenterer den Ăžkologiske psykologiske retning inden for community psykologi og viser, hvorledes den kan anvendes i psykologisk intervention over for psykiske traumer. Ăkologisk psykologi drejer sig om helheden af person-situation-omgivelser og dermed om tilpasningen mellem disse. Recovery og livskvalitet ses i denne forstĂ„elsesramme som balancen mellem de forskellige dele og den samlende ramme, de tilsammen udgĂžr. I artiklen gives et konkret eksempel pĂ„ de problemer, manglende tilpasning mellem en persons ressourcer, den sociale stĂžtte og de kollektive mestringsstrategier, kan give. Synsvinklen Ă„bner dermed for en interventionsform, der medtĂŠnker disse synsvinkler
Stress-testing the VBF approximation in multijet final states
We consider electro-weak Higgs plus three jets production at NLO QCD beyond
strict VBF acceptance cuts. We investigate, for the first time, how accurate
the VBF approximation is in these regions and within perturbative
uncertainties, by a detailed comparison of full and approximate calculations.
We find that a rapidity gap between the tagging jets guarantees a good
approximation, while an invariant mass cut alone is not sufficient, which needs
to be confronted with experimental choices. We also find that a significant
part of the QCD corrections can be attributed to Higgs-Strahlungs-type
topologies.Comment: 6 pages, 5 figures, add VBSCAN report numbe
Antibiotic Containing Bone Substitute in Major Hip Surgery:A Long Term Gentamicin Elution Study
Objectives: The objective is to present the antibiotic elution from a locally implanted gentamicin containing hydroxyapatite and calcium sulphate bone substitute with an extended follow up of 30 days. We also compare the pharmacokinetics of the ceramic bone substitute with a published study on gentamicin containing poly (methyl methacrylate) (PMMA) bone cement used in primary total hip arthroplasty. Methods: Gentamicin release was measured in the urine for a month and the serum for 4 days in 10 patients operated for trochanteric hip fractures and 10 patients in uncemented hip revisions. 17 patients were followed up at one year and 3 patients at 6 months. Results and Discussion: The gentamicin concentrations measured in serum were low and approximately 100 times less than in urine during the first days, indicating high local concentrations at the implant site. The elution from the biphasic bone substitute showed a stronger burst and higher gentamicin concentrations for the first week compared to that reported for PMMA used in hip arthroplasty. Also, for the bone substitute a complete gentamicin elution was obtained after 30 days, while for the PMMA cement sub-inhibitory MIC levels of gentamicin were still present in urine 60 days past surgery. No infections were detected. Conclusions: A new biphasic bone substitute containing antibiotics could potentially be used to prevent infection in patients treated for trochanteric hip fractures or uncemented hip revisions. The gentamicin elution from the bone substitute is efficient with high initial local gentamicin concentrations and complete release at 30 days
Online encoder-decoder anomaly detection using encoder-decoder architecture with novel self-configuring neural networks & pure linear genetic programming for embedded systems
Recent anomaly detection techniques focus on the use of neural networks and an encoder-decoder architecture. However, these techniques lead to trade offs if implemented in an embedded environment such as high heat management, power consumption and hardware costs. This paper presents two related new methods for anomaly detection within data sets gathered from an autonomous mini-vehicle with a CAN bus. The first method which to the best of our knowledge is the first use of encoder-decoder architecture for anomaly detection using linear genetic programming (LGP). Second method uses self-configuring neural network that is created using evolutionary algorithm paradigm learning both architecture and weights suitable for embedded systems. Both approaches have the following advantages: it is inexpensive regarding resource use, can be run on almost any embedded board due to linear register machine advantages in computation. The proposed methods are also faster by at least one order of magnitude, and it includes both inference and complete training
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