31 research outputs found
Planetary evolution with atmospheric photoevaporation II: Fitting the slope of the radius valley by combining boil-off and XUV-driven escape
The Kepler satellite has revealed a gap between sub-Neptunes and super-Earths
that atmospheric escape models had predicted as an evaporation valley. We seek
to contrast results from a simple XUV-driven energy-limited (ELIM) escape model
against those from a direct hydrodynamic (HYDRO) model. Besides XUV-driven
escape, the latter also includes the boil-off regime. We couple the two models
to an internal structure model and follow the planets' temporal evolution over
Gyr. To see the population-wide imprint of the two models, we first employ a
rectangular grid in initial conditions. We then study the slope of the valley
also for initial conditions derived from the Kepler planets. For the
rectangular grid, we find that the power-law slope of the valley with respect
to orbital period is -0.18 and -0.11 in the ELIM and HYDRO model, respectively.
For the initial conditions derived from the Kepler planets, the results are
similar (-0.16 and -0.10). While the slope found with the ELIM model is steeper
than observed, the one of the HYDRO model is in excellent agreement with
observations. The reason for the shallower slope is caused by the two regimes
in which the ELIM model fails: First, puffy planets at low stellar irradiation.
For them, boil-off dominates mass loss. However, boil-off is absent in the ELIM
model, thus it underestimates escape relative to HYDRO. Second, massive compact
planets at high XUV irradiation. For them, the ELIM approximation overestimates
escape relative to the HYDRO case because of cooling by thermal conduction,
neglected in the ELIM model. The two effects act together in concert to yield
in the HYDRO model a shallower slope of the valley that agrees very well with
observations. We conclude that an escape model that includes boil-off and a
more realistic treatment of cooling mechanisms can reproduce one of the most
important constraints, the valley slope.Comment: 20 pages, 11 figures, accepted to A&
A hybrid approach for alarm verification using stream processing, machine learning and text analytics
False alarms triggered by security sensors incur high costs for all parties involved. According to police reports, a large majority of alarms are false. Recent advances in machine learning can enable automatically classifying alarms. However, building a scalable alarm verification system is a challenge, since the system needs to: (1) process thousands of alarms in real-time, (2) classify false alarms with high accuracy and (3) perform historic data analysis to enable better insights into the results for human operators. This requires a mix of machine learning, stream and batch processing â technologies which are typically optimized independently. We combine all three into a single, real-world application.
This paper describes the implementation and evaluation of an alarm verification system we developed jointly with Sitasys, the market leader in alarm transmission in central Europe. Our system can process around 30K alarms per second with a verification accuracy of above 90%
A compact 20-pass thin-disk multipass amplifier stable against thermal lensing effects and delivering 330 mJ pulses with
We report on an Yb:YAG thin-disk multipass amplifier delivering 50 ns long
pulses at a central wavelength of 1030 nm with an energy of 330 mJ at a
repetition rate of 100 Hz. The beam quality factor at the maximum energy was
measured to be . The small signal gain is 20, and the gain
at 330 mJ was measured to be 6.9. The 20-pass amplifier is designed as a
concatenation of stable resonator segments in which the beam is alternately
Fourier transformed and relay-imaged back to the disk by a 4f-imaging optical
scheme stage. The Fourier transform propagation makes the output beam robust
against spherical phase front distortions, while the 4f-stage is used to
compensate the thermal lens of the thin-disk and to reduce the footprint of the
amplifier
Tuberculosis in HIV-Negative and HIV-Infected Patients in a Low-Incidence Country: Clinical Characteristics and Treatment Outcomes
BACKGROUND: In Switzerland and other developed countries, the number of tuberculosis (TB) cases has been decreasing for decades, but HIV-infected patients and migrants remain risk groups. The aim of this study was to compare characteristics of TB in HIV-negative and HIV-infected patients diagnosed in Switzerland, and between coinfected patients enrolled and not enrolled in the national Swiss HIV Cohort Study (SHCS).
METHODS AND FINDINGS: All patients diagnosed with culture-confirmed TB in the SHCS and a random sample of culture-confirmed cases reported to the national TB registry 2000-2008 were included. Outcomes were assessed in HIV-infected patients and considered successful in case of cure or treatment completion. Ninety-three SHCS patients and 288 patients selected randomly from 4221 registered patients were analyzed. The registry sample included 10 (3.5%) coinfected patients not enrolled in the SHCS: the estimated number of HIV-infected patients not enrolled in the SHCS but reported to the registry 2000-2008 was 146 (95% CI 122-173). Coinfected patients were more likely to be from sub-Saharan Africa (51.5% versus 15.8%, P<0.0001) and to present disseminated disease (23.9% vs. 3.4%, P<0.0001) than HIV-negative patients. Coinfected patients not enrolled in the SHCS were asylum seekers or migrant workers, with lower CD4 cell counts at TB diagnosis (median CD4 count 79 cells/”L compared to 149 cells/”L among SHCS patients, Pâ=â0.07). There were 6 patients (60.0%) with successful outcomes compared to 82 (88.2%) patients in the SHCS (Pâ=â0.023).
CONCLUSIONS: The clinical presentation of coinfected patients differed from HIV-negative TB patients. The number of HIV-infected patients diagnosed with TB outside the SHCS is similar to the number diagnosed within the cohort but outcomes are poorer in patients not followed up in the national cohort. Special efforts are required to address the needs of this vulnerable population
Parameter identification of the KUKA LBR iiwa robot including constraints on physical feasibility
The newly released KUKA LBR iiwa R820 robot stands for intelligent industrial work assistant (iiwa) and is, like its predecessor LBR IV, equipped with torque sensors in each joint, and can be controlled through a real-time interface. Although the dynamic model of the robot is not published by the manufacturer, its knowledge is indispensible for simulation and control based on the system model. This paper presents the identification of the minimal set of base parameters, as well as a consistent set of physical parameters, which are required for stable dynamic simulations, are identified by solving a nonlinear optimization problem, where constraints are included to ensure physical feasibility. A validation and cross-validation in simulation and experiments show a very accurate representation of the robot's dynamics by the resulting models. As a result, both sets of identified parameters are given.ISSN:2405-896
Spontanes retropharyngeales HĂ€matom mit letalem Ausgang.
Einleitung
Halsschmerz, Dysphagie und Dyspnoe sind die hĂ€ufigsten Symptomen, aufgrund derer Patienten einen Arzt aufsuchen. Hierbei handelt es sich um unspezifische Symptome mit vielfĂ€ltigen Ursachen. Mögliche im Retropharyngealraum lokalisierte Pathologien sind in der ĂŒberwiegenden Anzahl der FĂ€lle selbst limitierend oder durch medikamentöse Therapien beherrschbar (Bsp.: Pharyngitis, Tonsillitis, Seitenstrangangina). Deutlich seltener sind im Spatium retropharyngeum lokalisierte Abszesse, Neoplasien (Bsp.: Lipome, Neurofibrome, Liposarkome) oder HĂ€matome (SchmĂ€l F et al. HNO 2002; 50: 418âââ423). Letztlich können auch degenerative VerĂ€nderungen der WirbelsĂ€ule, eine ektop verlaufende Arteria carotis interna oder seltene Manifestationen von Systemerkrankungen (Bsp.: Sarkoidose) zu einer unterschiedlich stark ausgeprĂ€gten Vorwölbung der Pharynxhinterwand und Einengung der Luft- und Speiseröhre fĂŒhren.
Anhand des vorliegenden Falls wird die klinische PrÀsentation sowie die radiologische Diagnose eines retropharyngealen HÀmatoms diskutiert und die anatomische Beziehung der Halskompartimente mit besonderem Fokus auf den Retropharyngealraum dargestellt
Regional variation in orthopedic surgery in Switzerland
The study systematically describes the frequency and geographic variability of major surgical interventions for musculoskeletal disorders in Switzerland. Age- and sex-standardized rates for joint replacements, arthroscopies, spine surgery and hip fracture repair were calculated for hospital service regions. Various statistical analyses were used to measure the extent of variation. The authors argue that the surgery of hip fractures can be used as index surgery in the context of analyzing variations in orthopedic surgery. Temporal trends imply that patient demand and supply factors related to clinical ambiguity and non-medical incentives of providers are far more important components leading to increased use than the sole effect of an aging population
Spontanes retropharyngeales HĂ€matom mit letalem Ausgang
Halsschmerz, Dysphagie und Dyspnoe sind die hĂ€ufigsten Symptomen, aufgrund derer Patienten einen Arzt aufsuchen. Hierbei handelt es sich um unspezifische Symptome mit vielfĂ€ltigen Ursachen. Mögliche im Retropharyngealraum lokalisierte Pathologien sind in der ĂŒberwiegenden Anzahl der FĂ€lle selbst limitierend oder durch medikamentöse Therapien beherrschbar (Bsp.: Pharyngitis, Tonsillitis, Seitenstrangangina). Deutlich seltener sind im Spatium retropharyngeum lokalisierte Abszesse, Neoplasien (Bsp.: Lipome, Neurofibrome, Liposarkome) oder HĂ€matome (SchmĂ€l F et al. HNO 2002; 50: 418âââ423). Letztlich können auch degenerative VerĂ€nderungen der WirbelsĂ€ule, eine ektop verlaufende Arteria carotis interna oder seltene Manifestationen von Systemerkrankungen (Bsp.: Sarkoidose) zu einer unterschiedlich stark ausgeprĂ€gten Vorwölbung der Pharynxhinterwand und Einengung der Luft- und Speiseröhre fĂŒhren.
Anhand des vorliegenden Falls wird die klinische PrÀsentation sowie die radiologische Diagnose eines retropharyngealen HÀmatoms diskutiert und die anatomische Beziehung der Halskompartimente mit besonderem Fokus auf den Retropharyngealraum dargestellt
Cdh5/VE-cadherin Promotes Endothelial Cell Interface Elongation via Cortical Actin Polymerization during Angiogenic Sprouting
SummaryOrgan morphogenesis requires the coordination of cell behaviors. Here, we have analyzed dynamic endothelial cell behaviors underlying sprouting angiogenesis in vivo. Two different mechanisms contribute to sprout outgrowth: tip cells show strong migratory behavior, whereas extension of the stalk is dependent upon cell elongation. To investigate the function of Cdh5 in sprout outgrowth, we generated null mutations in the zebrafish cdh5 gene, and we found that junctional remodeling and cell elongation are impaired in mutant embryos. The defects are associated with a disorganization of the actin cytoskeleton and cannot be rescued by expression of a truncated version of Cdh5. Finally, the defects in junctional remodeling can be phenocopied by pharmacological inhibition of actin polymerization, but not by inhibiting actin-myosin contractility. Taken together, our results support a model in which Cdh5 organizes junctional and cortical actin cytoskeletons, as well as provides structural support for polymerizing F-actin cables during endothelial cell elongation