608 research outputs found
Mechanical Properties of Coronary Veins
There are several publications available and experiments were done regarding to the vessel biomechanical properties. In the range we could find in vitro and in vivo assessments data for elasticity properties. Even though we have many results in this topic we still don’t have enough data for special veins. Three coronary veins were investigated from pig’s heart. The aim of these experiments was to define and measure the longitudinal tensile stress and tensile strength of coronary veins. The tensile tests were done successfully and the tensile stress was defined in the range of 1.66-2.57 MPa
The PLATO End-to-End CCD Simulator -- Modelling space-based ultra-high precision CCD photometry for the assessment study of the PLATO Mission
The PLATO satellite mission project is a next generation ESA Cosmic Vision
satellite project dedicated to the detection of exo-planets and to
asteroseismology of their host-stars using ultra-high precision photometry. The
main goal of the PLATO mission is to provide a full statistical analysis of
exo-planetary systems around stars that are bright and close enough for
detailed follow-up studies. Many aspects concerning the design trade-off of a
space-based instrument and its performance can best be tackled through
realistic simulations of the expected observations. The complex interplay of
various noise sources in the course of the observations made such simulations
an indispensable part of the assessment study of the PLATO Payload Consortium.
We created an end-to-end CCD simulation software-tool, dubbed PLATOSim, which
simulates photometric time-series of CCD images by including realistic models
of the CCD and its electronics, the telescope optics, the stellar field, the
pointing uncertainty of the satellite (or Attitude Control System [ACS]
jitter), and all important natural noise sources. The main questions that were
addressed with this simulator were the noise properties of different
photometric algorithms, the selection of the optical design, the allowable
jitter amplitude, and the expected noise budget of light-curves as a function
of the stellar magnitude for different parameter conditions. The results of our
simulations showed that the proposed multi-telescope concept of PLATO can
fulfil the defined scientific goal of measuring more than 20000 cool dwarfs
brighter than mV =11 with a precision better than 27 ppm/h which is essential
for the study of earth-like exo-planetary systems using the transit method.Comment: 5 pages, submitted for the Proceedings of the 4th HELAS International
Conference: Seismological Challenges for Stellar Structur
The impact of exercise in improving executive function impairments among children and adolescents with ADHD, autism spectrum disorder, and fetal alcohol spectrum disorder: a systematic review and meta-analysis
Objective: he goal of this work was to perform a systematic review and meta-analysis evaluating and comparing exercise related improvements in various executive function (EF) domains among children and adolescents with attention-deficit hyperactivity disorder (ADHD), Autism Spectrum Disorders (ASD), and Fetal Alcohol Spectrum Disorders (FASD). Methods: A systematic literature research was conducted in PubMed, CENTRAL, and PsycInfo from October 1st, 2018 through January 30th, 2019 for original peer-reviewed articles investigating the relationship between exercise interventions and improvements in three domains of executive function (working memory, attention/set shifting, and response inhibition) among children and adolescents with ADHD, ASD, and FASD. Effect sizes (ES) were extracted and combined with random-effects meta-analytic methods. Covariates and moderators were then analyzed using meta-regression and subgroup analyses. Results: A total of 28 studies met inclusion criteria, containing information on 1,281 youth (N=1197 ADHD, N= 54 ASD, N=30 FASD). For ADHD, exercise interventions were associated with moderate improvements in attention/set-shifting (ES 0.38, 95% CI 0.01-0.75, k=14) and approached significance for working memory (ES 0.35, 95%CI -0.17-0.88, k=5) and response inhibition (ES 0.39, 95%CI -0.02-0.80, k=12). For ASD and FASD, exercise interventions were associated with large improvements in working memory (ES 1.36, 95%CI 1.08-1.64) and response inhibition (ES 0.78, 95%CI 0.21-1.35) and approached significance for attention/set-shifting (ES 0.69, 95% -0.28-1.66). There was evidence of substantial methodologic and substantive heterogeneity among studies. Sample size, mean age, study design, and the number or duration of intervention sessions did not significantly moderate the relationship between exercise and executive function. Conclusion: Exercise interventions among children and adolescents with neurodevelopmental disorders were associated with moderate improvements in executive function domains. Of note, studies of youth with ASD and FASD tended to report higher effect sizes compared to studies of youth with ADHD, albeit few existing studies. Exercise may be a potentially cost-effective and readily implementable intervention to improve executive function in these populations
A new method for the spectroscopic identification of stellar non-radial pulsation modes. II. Mode identification of the Delta Scuti star FG Virginis
We present a mode identification based on new high-resolution time-series
spectra of the non-radially pulsating Delta Scuti star FG~Vir (HD 106384, V =
6.57, A5V). From 2002 February to June a global Delta Scuti Network (DSN)
campaign, utilizing high-resolution spectroscopy and simultaneous photometry
has been conducted for FG~Vir in order to provide a theoretical pulsation
model. In this campaign we have acquired 969 Echelle spectra covering 147 hours
at six observatories. The mode identification was carried out by analyzing line
profile variations by means of the Fourier parameter fit method, where the
observational Fourier parameters across the line are fitted with theoretical
values. This method is especially well suited for determining the azimuthal
order m of non-radial pulsation modes and thus complementary with the method of
Daszynska-Daszkiewicz (2002) which does best at identifying the degree l. 15
frequencies between 9.2 and 33.5 c/d were detected spectroscopically. We
determined the azimuthal order m of 12 modes and constrained their harmonic
degree l. Only modes of low degree (l <= 4) were detected, most of them having
axisymmetric character mainly due to the relatively low projected rotational
velocity of FG Vir. The detected non-axisymmetric modes have azimuthal orders
between -2 and 1. We derived an inclination of 19 degrees, which implies an
equatorial rotational rate of 66 km/s.Comment: 14 pages, 26 figure
New ground-based observational methods and instrumentation for asteroseismology
Space instrumentation like SOHO, MOST, CoRoT and Kepler has been and is being
built to attain very high precision data to be used for asteroseismic analysis.
Nonetheless, there is a very strong need for providing additional information,
especially on mode identification. With this contribution I will review the
efforts been put on new ground-based instrumentation and the methodology that
can be used to achieve this aim.Comment: 6 pages. Review contribution to be published in Astrophysics and
Space Science Proceedings series (ASSP), in the proceedings of "20th Stellar
Pulsation Conference Series: Impact of new instrumentation and new insights
in stellar pulsations", 5-9 September 2011, Granada, Spai
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