julilili42/papers huggingface dataset:
Markov random field-based clustering of vibration data
2010-10-01

Abstract — A safe traversal of a mobile robot in an unknown environment requires the determination of local ground surface properties. As a first step, a broad structure of the underlying environment can be established by clustering terrain sections which exhibit similar features. In this work, we focus on an unsupervised learning approach to segment different terrain types according to the clustering of acquired vibration signals. Therefore, we present a Markov random field-based clustering approach taking the inherent temporal dependencies between consecutive measurements into account. The applied generative model assumes that the class labels of neighboring vibration segments are generated by prior distributions with similar parameters. A temporally constrained expectation maximization algorithm enables the efficient estimation of its parameters considering a predefined set of neighboring vibration segments. Since the size of the neighbor set proves to be data-dependent, we derive a general means of estimating this set size from the observed data. We show that the Markov random field clustering approach generates valid models for a variety of driving speeds even in situations of frequent terrain changes. I.
Body landmark detection for a fully automatic AAA stent graft planning software system
2010-10-01

In this paper, we present an approach to automate the planning of an endovascular stent graft for abdominal aortic aneurysms (AAAs), which are treated with bifurcated prosthesis (Y-stents) when located close to the iliac bifurcation. During the intervention, the folded Y-stent graft — consisting of several parts — is inserted via the iliac region and expanded inside the patient's body. The first step of the proposed approach is to detect different body landmarks with a statistical method. In the next step, these landmarks are used to calculate two vascular centerlines, which provide multiplanar reformatting (MPR) slices that are used for an automatic segmentation of the artery walls. The segmented artery walls provide the manufacturer specific measures to choose an adequate bifurcated prosthesis. In a final step, the expansion of the stent is simulated in the patient's data. Results for 50 abdominal aortic aneurysm cases provided by computed tomography angiography (CTA) acquisitions are successfully verified by a virtual stenting expert.
Orbital migration models under test
2010-10-01

Abstract Planet-disk interaction predicts a change in the orbital elements of an embedded planet. Through linear and fully hydrodynamical studies it has been found that migration is typically directed inwards. Hence, this migration process gives natural explanation for the presence of the ’hot’ planets orbiting close to the parent star, and it plays a mayor role in explaining the formation of resonant planetary systems. However, standard migration models for locally isothermal disks indicate a too rapid inward migration for small mass planets, and a large number of massive planets are found very far away from the star. Recent studies, including more complete disk physics, have opened up new paths to slow down or even reverse migration. The new findings on migration are discussed and connected to the observational properties of planetary systems.
Conditions for outward migration
2010-10-01

Abstract The migration of protoplanets in discs not only depends on the thermodynamics of the ambient disc but also on the orbital parameters of the embedded planet. In the fully radiative regime, planets can migrate outward if their orbital parameters fit in a very small range. We simulate planets in fully radiative discs (and isothermal discs - for reference) and determine the influence of the orbital parameters ( a , e and i ) and the planetary mass on the migration time scale and direction.
RTOS-aware modeling of embedded hardware/software systems
2010-10-01

Modern embedded systems such as mobile phones or electronic control units from the automotive domain include a bulk of highly complex and highly interacting functions. Due to several reasons-flexibility and cost effectiveness may be the most important ones-a large and permanently growing part of these functions is implemented in software. This comes along with the demand for more and more processing power, paving the way for multi-core architectures, and widespread use of real-time operating systems. Application software implementation and operating system configuration strongly influence the overall system behavior. Design methodologies for such complex systems, consisting of hardware, software and real-time operating systems, must provide an early, model-based view on the overall system. The approach described in this paper enables automatic generation of system-level models of complex systems from abstract application specifications. Additionally, a compiler-based technique allows automatic calculation of precise software runtime information and annotation of the generated model. The resulting system-level model facilitates early exploration of systems on high level of abstraction, taking into account functional and temporal characteristics of hardware, software and real-time operating system. A key feature of the approach is its high accuracy, which is shown by applying it to an industrial application from the automotive domain.
Self-resonant modes in Josephson junctions with a phase discontinuity
2010-10-01

We extend the theory of self-resonances in short Josephson junctions to the case of a piecewise constant critical current density and a κ discontinuity in the Josephson phase. We calculate the amplitude of the self-resonances as a function of applied magnetic field by using an extension of the approach introduced by Kulik for conventional Josephson junctions (I. O. Kulik, JETP Lett. 2, 84 (1965)). The theory given here agrees with existing experiments on superconducting–insulator–ferromagnet–superconductor 0–π Josephson junctions. The results are relevant to the characterization of all modern 0–π junctions as well as 0–κ junctions with artificially created phase discontinuities: high-temperature grain boundary junctions, junctions with a ferromagnetic barrier, and junctions with current injectors.
OP10.06: Influence of second trimester placental volume, shell volume and intraplacental circulation on birth weight
2010-10-01

Fetal growth anomalies may be caused by impaired placentation and reduced placental circulation. In the second trimester placental volume and vascularization can be assessed by 3D ultrasound and 3D power Doppler. Thus, we investigated the influence of placental volume parameters, placental shell volumes and intraplacental circulation on birth weight. 111 patients with singleton pregnancy and gestational age between 14 + 4 and 18 + 0 weeks were included in this study. Fetal biometry with regard to biparietal diameter (BPD), head circumference (HC), abdominal circumference (AC) and femur length (FL) was routinely performed. Placental volume (PV), five placental ratios (PR1 = PV/BPD; PR2 = PV/HC; PR3 = PV/AC, PR4 = PV/FL, PR5 = PV/FI) and flow indices (FI) were calculated by using the VOCAL software program. Furthermore, shell volumes, defined as the outer 3 mm and 5 mm layer of each placenta and their corresponding FI were measured. In linear regression analysis PV and PR1-4 but not FI of the entire placenta were significantly associated birth weight. However, these parameters were unable to predict birth weight below the 10th and above the 90th percentile in a logistic regression model. Focusing on the placental shell volumes could enhance the significance and correlations between PV, all five placental ratios and birth weight as demonstrated in linear regression analysis. Second trimester placental volume parameters alone are significantly associated with birth weight. Placental shell measurements at the early 2nd trimester show a weak correlation between placental vascularization and birth weight. Therefore, this technique may allow more insight into intraplacental circulation in its outer parts.
OP38.02: Association between birth weight and second trimester 3D placental volumetry, intraplacental vascularization and amniotic fluid cytokines
2010-10-01

The placenta is of utmost importance for fetal growth and well-being. Defective placentation and impaired placental circulation may result in anomalies of fetal growth. Growth factors and cytokines in the amniotic fluid may reflect changes in placental function and fetal growth. Therefore, it was our aim to investigate whether 3D placental volume parameters, intraplacental circulation and different amniotic fluid parameters are associated with birth weight. 210 patients with singleton pregnancy and gestational age between 15 + 0 and 17 + 6 weeks were included in our study. Fetal biometry with regard to biparietal diameter (BPD), head circumference (HC), abdominal circumference (AC) and femur length (FL) was routinely performed. Placental volume and vascularization were assessed by 3D ultrasound and 3D power Doppler. Placental volume (PV), four placental ratios (PR1 = PV/BPD; PR2 = PV/HC; PR3 = PV/AC, PR4 = PV/FL) and vascularization indices (VI, FI, VFI) were calculated. Visfatin, leptin, endoglin, VEGF and PIGF were measured in the amniotic fluid. While in linear regression analysis both PV, the four placental ratios, VI and VFI had a significant influence on birth weight only FI significantly predicted birth weight below the 10th percentile in logistic regression analysis. Leptin and Visfatin in the amniotic fluid were significantly associated with birth weight in linear regression analysis. The same applied to VEGF and PV/FI. Second trimester placental volume and vascularization parameters correlate with birth weight. Additionally, leptin and visfatin in the amniotic are associated with fetal development. Placental volumetry and vacularization may be early markers for fetal growth anomalies.
3D global simulations of proto-planetary disk with dynamically evolving outer edge of dead zone
2010-10-01

Abstract 3D global MHD simulations of magneto-driven turbulence are performed for the disk of 100 AU with reduced amount of 10μm fluffy dust grains. We use X-ray and cosmic ray ionization, as well as simplified treatment of recombination on dust grains. The ionization of gas and charging of dust grains are dynamically evolving during the simulation, making the zone of high magnetic dissipation (’dead’ zone) variable. In our simulations, the jump in MRI-driven turbulent viscosity inside and outside of dead zone is insignificant. We find no hard edge, but rather a smooth transition between active and dead zone. Subsequently, there is no visible pressure bump at outer edge of the dead zone.
Porosity models for pre-planetesimals: modified P-α like models and the effect of dissipated energy
2010-10-01

Abstract The outcome of collisions between pre-planetesimals is important in the theory of planetesimal formation by collisional growth and strongly depends on their internal structure . Since pre-planetesimals are highly porous , reaching 90% porosity, they could show the so called anomalous behaviour (decrease of density during shock compression, e.g. Bolkhovitinov &amp; Khvostov 1978). Due to involved sizes (&gt;dm), laboratory experiments are unfeasible therefore numerical simulations equipped with adequate porosity models are necessary. Here we focus on the P -α model and its variations. We found that they are suitable for applications in the high porosity range only after a modification of the basic equations, that avoids an inconsistency and takes into account the effect of dissipated energy, is performed.
Evaluation of Inter-Observer Agreement Shows that Intercellular Space Distance is a Reliable Marker of GERD
2010-10-01

Purpose: Intercellular Space Distance (ISD) of esophageal epithelium measured by electron microscopy (EM) has been shown to be an early morphological maker of GERD, present in patients with heartburn even when endoscopy is normal (i.e. no erosive esophagitis). Although ISD has been shown to be a useful marker of GERD in several studies, the reliability of ISD measurements has not been tested. Our purpose was to evaluate the inter-observer agreement, correlation, and concordance for ISD measured in patients with normal and dilated ISD. Methods: We evaluated inter-observer agreement and correlation for ISD measured by two blinded independent observers in 10 subjects: 6 GERD patients (heartburn plus erosive esophagitis or abnormal impedance-pH monitoring) and 4 healthy controls with normal endoscopy and negative impedance-pH monitoring. All subjects underwent endoscopy with biopsies taken 5 cm above the esophagogastric junction. ISD was determined by transmission EM of esophageal biopsies at 5,000x magnification using computer-assisted morphometry (Image J software). 10 measurements of ISD were taken in each of 10 micrographs; mean patient ISD was the average of these 100 measurements. Mean ISD per patient and per micrograph was determined by the 2 blinded independent observers; Cohen's kappa for interobserver agreement, as well as Pearson correlation coefficient were calculated. In addition, concordance between the two readers for a diagnosis of normal versus increased ISD was assessed (upper limit of normal ISD was defined as 0.69 μm in a previous study). Results: Mean ISD for each patient measured by the two observers is shown in the table. We found substantial agreement between the two observers for average patient ISD (Kappa=0.78, correlation coefficient=0.99) as well as for average micrograph ISD (Kappa=0.82, correlation coefficient=0.96 photograph). Both observers 1 and 2 found increased mean ISD (> 0. 69 μm) in the 6 GERD patients; observer 1 found normal ISD in the 4 healthy controls; observer 2 found normal ISD in 3 of 4 controls, for a total concordance in 9/10 individuals. Conclusion: The substantial inter-observer agreement, good correlation and high concordance for measurement of ISD indicates that this is a reliable method, lending further support to its use as a marker of GERD. The findings should be confirmed in a larger study.Table: [41]
Diazepam Decreases Action Potential Firing of Neocortical Neurons via Two Distinct Mechanisms
2010-10-02

Diazepam induced a biphasic attenuation of spontaneous action potential firing of neocortical neurons. Low to moderate concentrations caused a monotonic, mild depression that is mediated via the classical binding site as it is antagonized by flumazenil. However, the effects of diazepam observed at high concentrations were not affected by flumazenil. Hence, these findings support the concept of at least 2 different binding sites for benzodiazepines on γ-aminobutyric acid type A receptors. Furthermore, our results are consistent with the hypothesis that the classical high-affinity binding site mediates low-dose diazepam actions, such as amnesia, anxiolysis, and sedation, while a second, nonclassical and independent site contributes to the anesthetic effects of diazepam, such as hypnosis and immobility.
Impact of restrictive physiology on intrinsic diastolic right ventricular function and lusitropy in children and adolescents after repair of tetralogy of Fallot
2010-10-03

Background Restrictive right ventricular (RV) physiology is a phenomenon considered potentially beneficial when detected in children and adolescents with repaired tetralogy of Fallot (ToF). It is typically characterised by antegrade flow in the pulmonary artery in late diastole at the time of atrial contraction. However, little is known about the impact of restrictive physiology on intrinsic diastolic RV function or lusitropy. Methods Diastolic function was prospectively assessed at baseline level and during dobutamine infusion using the pressure–volume conductance system. End diastolic forward flow in the pulmonary artery was measured by MRI. Results Twenty-five patients aged 17.9±7.5 years were studied. Although the end diastolic RV pressure, the time constant of isovolumic RV relaxation (τ) and dP/dtmin were similar between both groups, the slope of the end diastolic pressure–volume relationship (Eed) was significantly higher in the restrictive group indicating increased diastolic stiffness in these patients (0.14±0.05 vs 0.06±0.01, p=0.03). Dobutamine stress, however, led to an increase in Eed in the entire ToF cohort indicating an abnormal diastolic response to catecholamines in these patients. Conclusions Diastolic RV stiffness of repaired ToF patients with restrictive physiology is increased. The lusitropic response of the RV to β adrenergic agents is abnormal after ToF repair regardless of whether restrictive physiology is present or not. This has potential implications, particularly for postoperative drug management.
Long life of Gauss-Bonnet corrected black holes
2010-10-05

Dictated by the string theory and various higher dimensional scenarios, black holes in D &gt; 4-dimensional space-times must have higher curvature corrections. The first and dominant term is quadratic in curvature, and called the Gauss-Bonnet (GB) term. We shall show that although the Gauss-Bonnet correction changes black hole's geometry only softly, the emission of gravitons is suppressed by many orders even at quite small values of the GB coupling. The huge suppression of the graviton emission is due to the multiplication of the two effects: the quick cooling of the black hole when one turns on the GB coupling and the exponential decreasing of the gray-body factor of the tensor type of gravitons at small and moderate energies. At higher D the tensor gravitons emission is dominant, so that the overall lifetime of black holes with Gauss-Bonnet corrections is many orders larger than was expected. This effect should be relevant for the future experiments at the Large Hadron Collider (LHC).
Binocular rivalry: A time dependence of eye and stimulus contributions
2010-10-05

In binocular rivalry, the visual percept alternates stochastically between two dichoptically presented stimuli. It is established that both processes related to the eye of origin and binocular, stimulus-related processes account for these fluctuations in conscious perception. Here we studied how their relative contributions vary over time. We applied brief disruptions to rivalry displays, concurrent with an optional eye swap, at varying time intervals after one stimulus became visible (dominant). We found that early in a dominance phase the dominant eye determined the percept by stabilizing its own contribution (regardless of the stimulus), with an additional yet weaker stabilizing contribution of the stimulus (regardless of the eye). Their stabilizing contributions declined in parallel with time so that late in a dominance phase the stimulus (and in some cases also the eye-based) contribution turned negative, favoring a perceptual (or ocular) switch. Our findings show that depending on the time, first processes related to the eye of origin and then those related to the stimulus can have a greater net influence on the stability of the conscious percept. Their co-varying change may be due to feedback from image- to eye-of-origin representations.
Antitumor Activity of Glycosylated Molluscan Hemocyanins via Guerin Ascites Tumor
2010-10-05

As observed in most molluscan hemocyanins, high-mannose type glycans were identified in hemocyanins from Rapana venosa (RvH), Helix lucorum (HlH) and keyhole limpet (Megatura crenulata). In addition, a glycan with a branching structure containing xylose, fucose and terminal methyl hexose was identified in β-HlH. We have examined the immuno-adjuvant properties of hemocyanins, their derivatives and conjugates associated with the cell mediated immunity in experimental tumor-bearing animals with ascites tumor of Guerin. After immunization of the animals with the experimental vaccine preparations, the highest values of splenic lymphocytes were observed in groups immunized with the conjugates RvH-TAg, β-HlH-TAg and KLH-TAg (42.3%; 40.8% and 40.58%, respectively) than with the native hemocyanins (36.5%; 35.1% and 32.4%, respectively). The immunization of rats with the hemocyanins β-HlH, RvH and KLH and their conjugates, prolonged the median survival time of tumor-bearing animals compared with non-immunized animals (39, 33, 31 and 7 days, respectively). Both hemocyanins β-HlH and RvH activate the immune system of the experimental animals and therefore could be a good alternative for KLH. For this reason they could be included into the composition of non-specific anti-tumor vaccines to enhance their effectiveness.
Propagation of Seasonal Temperature Signals into an Aquifer upon Bank Infiltration
2010-10-06

Infiltrating river water carries the temperature signal of the river into the adjacent aquifer. While the diurnal temperature fluctuations are strongly dampened, the seasonal fluctuations are much less attenuated and can be followed into the aquifer over longer distances. In one‐dimensional model with uniform properties, this signal is propagated with a retarded velocity, and its amplitude decreases exponentially with distance. Therefore, time shifts in seasonal temperature signals between rivers and groundwater observation points may be used to estimate infiltration rates and near‐river groundwater velocities. As demonstrated in this study, however, the interpretation is nonunique under realistic conditions. We analyze a synthetic test case of a two‐dimensional cross section perpendicular to a losing stream, accounting for multi‐dimensional flow due to a partially penetrating channel, convective‐conductive heat transport within the aquifer, and heat exchange with the underlying aquitard and the land surface. We compare different conceptual simplifications of the domain in order to elaborate on the importance of different system elements. We find that temperature propagation within the shallow aquifer can be highly influenced by conduction through the unsaturated zone and into the underlying aquitard. In contrast, regional groundwater recharge has no major effect on the simulated results. In our setup, multi‐dimensionality of the flow field is important only close to the river. We conclude that over‐simplistic analytical models can introduce substantial errors if vertical heat exchange at the aquifer boundaries is not accounted for. This has to be considered when using seasonal temperature fluctuations as a natural tracer for bank infiltration.
Operational assimilation of GPS slant path delay measurements into the MM5 4DVAR system
2010-10-06

A forward operator for Global Positioning System (GPS) slant total delay (STD) data and its adjoint were implemented into the Mesoscale Model version 5 (MM5) 4DVAR system to investigate its impact on quantitative precipitation forecasting (QPF). An operational forecast system was set up providing two forecasts per day, one driven by ECMWF forecasts only and the other additionally by 4DVAR of GPS STD data. The investigation of statistics for August 2007 demonstrated a positive impact on the representation of the water-vapour field and the diurnal cycle of precipitation in southwest Germany. The spread of observation-minus-model departures was strongly reduced during the first 6 h of the simulations. As compared to the control simulation, the averaged diurnal cycle of precipitation in the 4DVAR integration was closer to observations in spite of the limitations of the 4DVAR system. Especially promising is the almost complete removal of the spin-up at the beginning of the simulation. This study not only demonstrates the potential of water vapour data assimilation for nowcasting and short-range QPF. It also suggests that improved GPS retrievals and extended networks are important to further improve the forecast performance and demonstrates the potential to apply observation operators for model verification.