112 research outputs found

    Modelling of Dynamic Games with Imperfect Information

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    Práce se zabývá studiem sekvenčních strategických her a to převážně her s nedokonalou informací, návrhem strategické situace vykazující prvky nedokonalé informace, implementací modelu a experimentováním s modelem. Pro práci byla zvolena hra DarkElf. Jedná se o tahovou strategickou ekonomicko-vojenskou hru, v níž se výsledné akce hráčů aplikují současně v předem známý okamžik.This work concentrates on the study of dynamic games; in particular games with imperfect information, implementation of a model and experimentation with the model. The game DarkElf was chosen for this project. It is a strategic, turn based game with economic and military features, where the decisions made by players are simultaneously implemented at a predetermined time.

    Model of Strategic Decision-Making in a Multi-Player Game with Aspects of Cooperation

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    Práce se zabývá studiem matematických modelů lidského chování v sekvenčních strategických hrách, návrhem strategické situace vykazující prvky kooperace, implementací modelu a experimentováním s modelem. Pro práci byla zvolena hra DarkElf. Jedná se o tahovou strategickou ekonomicko-vojenskou hru, v níž se výsledné akce hráčů aplikují současně v předem známý okamžik.This work concentrates on the study of mathematical models of human behaviour in dynamic games; in particular games with aspects of cooperation, implementation of a model and experimentation with the model. The game DarkElf was chosen for this project. It is a strategic, turn based game with economic and military features, where the decisions made by players are simultaneously implemented at a predetermined time.

    MusE GAs FLOw and Wind (MEGAFLOW) I: First MUSE results on background quasars

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    The physical properties of galactic winds are one of the keys to understand galaxy formation and evolution. These properties can be constrained thanks to background quasar lines of sight (LOS) passing near star-forming galaxies (SFGs). We present the first results of the MusE GAs FLOw and Wind (MEGAFLOW) survey obtained of 2 quasar fields which have 8 MgII absorbers of which 3 have rest-equivalent width greater than 0.8 \AA. With the new Multi Unit Spectroscopic Explorer (MUSE) spectrograph on the Very Large Telescope (VLT), we detect 6 (75%\%) MgII host galaxy candidates withing a radius of 30 arcsec from the quasar LOS. Out of these 6 galaxy--quasar pairs, from geometrical arguments, one is likely probing galactic outflows, two are classified as "ambiguous", two are likely probing extended gaseous disks and one pair seems to be a merger. We focus on the wind-pair and constrain the outflow using a high resolution quasar spectra from Ultraviolet and Visual Echelle Spectrograph (UVES). Assuming the metal absorption to be due to gas flowing out of the detected galaxy through a cone along the minor axis, we find outflow velocities of the order of \approx 150 km/s (i.e. smaller than the escape velocity) with a loading factor, η=M˙out/\eta =\dot M_{\rm out}/SFR, of \approx 0.7. We see evidence for an open conical flow, with a low-density inner core. In the future, MUSE will provide us with about 80 multiple galaxy-quasar pairs in two dozen fields.Comment: 20 pages, 16 figures, accepted for publication in Ap

    Ubiquitous giant Ly α\alpha nebulae around the brightest quasars at z3.5z\sim3.5 revealed with MUSE

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    Direct Ly α\alpha imaging of intergalactic gas at z2z\sim2 has recently revealed giant cosmological structures around quasars, e.g. the Slug Nebula (Cantalupo et al. 2014). Despite their high luminosity, the detection rate of such systems in narrow-band and spectroscopic surveys is less than 10%, possibly encoding crucial information on the distribution of gas around quasars and the quasar emission properties. In this study, we use the MUSE integral-field instrument to perform a blind survey for giant Ly α\alpha nebulae around 17 bright radio-quiet quasars at 3<z<43<z<4 that does not suffer from most of the limitations of previous surveys. After data reduction and analysis performed with specifically developed tools, we found that each quasar is surrounded by giant Ly α\alpha nebulae with projected sizes larger than 100 physical kpc and, in some cases, extending up to 320 kpc. The circularly averaged surface brightness profiles of the nebulae appear very similar to each other despite their different morphologies and are consistent with power laws with slopes 1.8\approx-1.8. The similarity between the properties of all these nebulae and the Slug Nebula suggests a similar origin for all systems and that a large fraction of gas around bright quasars could be in a relatively "cold" (T\sim104^4K) and dense phase. In addition, our results imply that such gas is ubiquitous within at least 50 kpc from bright quasars at 3<z<43<z<4 independently of the quasar emission opening angle, or extending up to 200 kpc for quasar isotropic emission.Comment: 19 pages, 9 figures, 3 Tables, accepted to Ap

    Possible Signatures of a Cold-Flow Disk from MUSE using a z=1 galaxy--quasar pair towards SDSSJ1422-0001

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    We use a background quasar to detect the presence of circum-galactic gas around a z=0.91z=0.91 low-mass star forming galaxy. Data from the new Multi Unit Spectroscopic Explorer (MUSE) on the VLT show that the host galaxy has a dust-corrected star-formation rate (SFR) of 4.7±\pm0.2 Msun/yr, with no companion down to 0.22 Msun/yr (5 σ\sigma) within 240 kpc (30"). Using a high-resolution spectrum (UVES) of the background quasar, which is fortuitously aligned with the galaxy major axis (with an azimuth angle α\alpha of only 1515^\circ), we find, in the gas kinematics traced by low-ionization lines, distinct signatures consistent with those expected for a "cold flow disk" extending at least 12 kpc (3×R1/23\times R_{1/2}). We estimate the mass accretion rate M˙in\dot M_{\rm in} to be at least two to three times larger than the SFR, using the geometric constraints from the IFU data and the HI column density of logNHI20.4\log N_{\rm HI} \simeq 20.4 obtained from a {\it HST}/COS NUV spectrum. From a detailed analysis of the low-ionization lines (e.g. ZnII, CrII, TiII, MnII, SiII), the accreting material appears to be enriched to about 0.4 ZZ_\odot (albeit with large uncertainties: logZ/Z=0.4 ± 0.4\log Z/Z_\odot=-0.4~\pm~0.4), which is comparable to the galaxy metallicity (12+logO/H=8.7±0.212+\log \rm O/H=8.7\pm0.2), implying a large recycling fraction from past outflows. Blue-shifted MgII and FeII absorptions in the galaxy spectrum from the MUSE data reveal the presence of an outflow. The MgII and FeII doublet ratios indicate emission infilling due to scattering processes, but the MUSE data do not show any signs of fluorescent FeII* emission.Comment: 17 pages, 11 figures, in press (ApJ), minor edits after the proofs. Data available at http://muse-vlt.eu/science/j1422

    Determining initial and follow-up costs of cardiovascular events in a US managed care population

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    <p>Abstract</p> <p>Background</p> <p>Cardiovascular (CV) events are prevalent and expensive worldwide both in terms of direct medical costs at the time of the event and follow-up healthcare after the event. This study aims to determine initial and follow-up costs for cardiovascular (CV) events in US managed care enrollees and to compare to healthcare costs for matched patients without CV events.</p> <p>Methods</p> <p>A 5.5-year retrospective matched cohort analysis of claims records for adult enrollees in ~90 US health plans. Patients hospitalized for first CV event were identified from a database containing a representative sample of the commercially-insured US population. The CV-event group (n = 29,688) was matched to a control group with similar demographics but no claims for CV-related events. Endpoints were total direct medical costs for inpatient and outpatient services and pharmacy (paid insurance amount).</p> <p>Results</p> <p>Overall, mean initial inpatient costs were US dollars ()16,981percase(standarddeviation[SD]=) 16,981 per case (standard deviation [SD] = 20,474), ranging from 6,699foratransientischemicattack(meanlengthofstay[LOS]=3.7days)to6,699 for a transient ischemic attack (mean length of stay [LOS] = 3.7 days) to 56,024 for a coronary artery bypass graft (CABG) (mean LOS = 9.2 days). Overall mean health-care cost during 1-year follow-up was 16,582(SD=16,582 (SD = 34,425), an excess of 13,792overthemeancostofmatchedcontrols.ThisdifferenceinaveragecostsbetweenCVeventandmatchedcontrolsubjectswas13,792 over the mean cost of matched controls. This difference in average costs between CV-event and matched-control subjects was 20,862 and 26,014aftertwoandthreeyearsoffollowup.Meanoverallinpatientcostsforsecondeventsweresimilartothoseforfirstevents(26,014 after two and three years of follow-up. Mean overall inpatient costs for second events were similar to those for first events (17,705/case; SD = $22,703). The multivariable regression model adjusting for demographic and clinical characteristics indicated that the presence of a CV event was positively associated with total follow-up costs (P < 0.0001).</p> <p>Conclusions</p> <p>Initial hospitalization and follow-up costs vary widely by type of CV event. The 1-year follow-up costs for CV events were almost as high as the initial hospitalization costs, but much higher for 2- and 3-year follow-up.</p

    Small conductance calcium-activated potassium current is important in transmural repolarization of failing human ventricles

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    BACKGROUND: The transmural distribution of apamin-sensitive small conductance Ca(2+)-activated K(+) (SK) current (IKAS) in failing human ventricles remains unclear. METHODS AND RESULTS: We optically mapped left ventricular wedge preparations from 12 failing native hearts and 2 rejected cardiac allografts explanted during transplant surgery. We determined transmural action potential duration (APD) before and after 100 nmol/L apamin administration in all wedges and after sequential administration of apamin, chromanol, and E4031 in 4 wedges. Apamin prolonged APD from 363 ms (95% confidence interval [CI], 341-385) to 409 (95% CI, 385-434; P<0.001) in all hearts, and reduced the transmural conduction velocity from 36 cm/s (95% CI, 30-42) to 32 cm/s (95% CI, 27-37; P=0.001) in 12 native failing hearts at 1000 ms pacing cycle length (PCL). The percent APD prolongation is negatively correlated with baseline APD and positively correlated with PCL. Only 1 wedge had M-cell islands. The percentages of APD prolongation in the last 4 hearts at 2000 ms PCL after apamin, chromanol, and E4031 were 9.1% (95% CI, 3.9-14.2), 17.3% (95% CI, 3.1-31.5), and 35.9% (95% CI, 15.7-56.1), respectively. Immunohistochemical staining of subtype 2 of SK protein showed increased expression in intercalated discs of myocytes. CONCLUSIONS: SK current is important in the transmural repolarization in failing human ventricles. The magnitude of IKAS is positively correlated with the PCL, but negatively correlated with APD when PCL is fixed. There is abundant subtype 2 of SK protein in the intercalated discs of myocytes

    Simultaneous Recordings of Intrinsic Cardiac Nerve Activities and Skin Sympathetic Nerve Activities From Human Patients During the Postoperative Period

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    Background Intrinsic cardiac nerve activity (ICNA) and skin nerve activity (SKNA) are both associated with cardiac arrhythmias in dogs. Objective The purpose of this study was to test the hypothesis that ICNA and SKNA correlate with postoperative cardiac arrhythmias in humans. Methods Eleven patients (mean age 60 ± 13 years; 4 women) were enrolled in this study. Electrical signals were simultaneously recorded from electrocardiogram (ECG) patch electrodes on the chest wall and from 2 temporary pacing wires placed during open heart surgery on the left atrial epicardial fat pad. The signals were filtered to display SKNA and ICNA. Premature atrial contractions (PACs) and premature ventricular contractions were determined manually. The SKNA and ICNA of the first 300 minutes of each patient were calculated minute by minute to determine baseline average amplitudes of nerve activities and to determine their correlation with arrhythmia burden. Results We processed 1365 ± 973 minutes of recording per patient. Low-amplitude SKNA and ICNA were present at all time, while the burst discharges were observed much less frequently. Both SKNA and burst ICNA were significantly associated with the onset of PACs and premature ventricular contractions. Baseline average ICNA (aICNA), but not average SKNA, had a significant association with PAC burden. The correlation coefficient (r) between aICNA and PAC burden was 0.78 (P < .01). A patient with the greatest aICNA developed postoperative atrial fibrillation. Conclusion ICNA and SKNA can be recorded from human patients in the postoperative period. The baseline magnitude of ICNA correlates with PAC burden and development of postoperative atrial fibrillation

    Data quality and patient characteristics in European ANCA-associated vasculitis registries: data retrieval by federated querying

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    Objectives This study aims to describe the data structure and harmonisation process, explore data quality and define characteristics, treatment, and outcomes of patients across six federated antineutrophil cytoplasmic antibody-associated vasculitis (AAV) registries.Methods Through creation of the vasculitis-specific Findable, Accessible, Interoperable, Reusable, VASCulitis ontology, we harmonised the registries and enabled semantic interoperability. We assessed data quality across the domains of uniqueness, consistency, completeness and correctness. Aggregated data were retrieved using the semantic query language SPARQL Protocol and Resource Description Framework Query Language (SPARQL) and outcome rates were assessed through random effects meta-analysis.Results A total of 5282 cases of AAV were identified. Uniqueness and data-type consistency were 100% across all assessed variables. Completeness and correctness varied from 49%–100% to 60%–100%, respectively. There were 2754 (52.1%) cases classified as granulomatosis with polyangiitis (GPA), 1580 (29.9%) as microscopic polyangiitis and 937 (17.7%) as eosinophilic GPA. The pattern of organ involvement included: lung in 3281 (65.1%), ear-nose-throat in 2860 (56.7%) and kidney in 2534 (50.2%). Intravenous cyclophosphamide was used as remission induction therapy in 982 (50.7%), rituximab in 505 (17.7%) and pulsed intravenous glucocorticoid use was highly variable (11%–91%). Overall mortality and incidence rates of end-stage kidney disease were 28.8 (95% CI 19.7 to 42.2) and 24.8 (95% CI 19.7 to 31.1) per 1000 patient-years, respectively.Conclusions In the largest reported AAV cohort-study, we federated patient registries using semantic web technologies and highlighted concerns about data quality. The comparison of patient characteristics, treatment and outcomes was hampered by heterogeneous recruitment settings
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