555 research outputs found
Echocardiographic evaluation of left ventricular morphology and function in young male football players and runners
Background: Long-term physical exercise leads to left ventricular morphological adaptations,
which vary with the kind of sport and the intensity and extent of the training. Although
the echocardiographic changes related to exercise in athletes participating in various sports
have been well described, changes associated with football players have been less well documented.
The aim of this study was to investigate the morphological adaptations of the heart to
athletic training and to compare by means of echocardiography the left ventricular dimensions,
masses and systolic functions of runners and football players.
Methods: A total of 40 male football players, 18 male long and middle-distance runners and
25 sedentary males were enrolled to the study and M-mode and two-dimensional
echocardiograms with Doppler analysis were performed in all subjects.
Results: The runners and football players were shown to have significantly greater left ventricular
end-diastolic internal dimensions, left ventricular mass (corrected for body mass,
height and body surface area), end-diastolic interventricular septum thicknesses and ejection
fraction values than a control group. The present results show no significant difference between
the left ventricular adaptations of runners and football players except when the left
ventricular mass is indexed with body mass, the runners being thinner.
Conclusions: The present results show that the echocardiographic findings of left ventricular
adaptations in runners and football players are quite similar and lead to physiological enlargement
of the heart. (Cardiol J 2007; 14: 37–43
Infinitely Large New Dimensions
We construct intersecting brane configurations in Anti-de-Sitter space
localizing gravity to the intersection region, with any number of extra
dimensions. This allows us to construct two kinds of theories with infinitely
large new dimensions, TeV scale quantum gravity and sub-millimeter deviations
from Newton's Law. The effective 4D Planck scale is determined in
terms of the fundamental Planck scale and the radius of curvature
via the familiar relation ; acts as an
effective radius of compactification for gravity on the intersection. Taking
TeV and sub-mm reproduces the phenomenology of theories
with large extra dimensions. Alternately, taking ,
and placing our 3-brane a distance away from the
intersection gives us a theory with an exponential determination of the
Weak/Planck hierarchy.Comment: 4 pages, revtex, no figure
A hybrid modular approach for dynamic fault tree analysis
YesOver the years, several approaches have been developed for the quantitative analysis of dynamic fault trees (DFTs). These approaches have strong theoretical and mathematical foundations; however, they appear to suffer from the state-space explosion and high computational requirements, compromising their efficacy. Modularisation techniques have been developed to address these issues by identifying and quantifying static and dynamic modules of the fault tree separately by using binary decision diagrams and Markov models. Although these approaches appear effective in reducing computational effort and avoiding state-space explosion, the reliance of the Markov chain on exponentially distributed data of system components can limit their widespread industrial applications. In this paper, we propose a hybrid modularisation scheme where independent sub-trees of a DFT are identified and quantified in a hierarchical order. A hybrid framework with the combination of algebraic solution, Petri Nets, and Monte Carlo simulation is used to increase the efficiency of the solution. The proposed approach uses the advantages of each existing approach in the right place (independent module). We have experimented the proposed approach on five independent hypothetical and industrial examples in which the experiments show the capabilities of the proposed approach facing repeated basic events and non-exponential failure distributions. The proposed approach could provide an approximate solution to DFTs without unacceptable loss of accuracy. Moreover, the use of modularised or hierarchical Petri nets makes this approach more generally applicable by allowing quantitative evaluation of DFTs with a wide range of failure rate distributions for basic events of the tree.This work was supported in part by the Dependability Engineering Innovation for Cyber Physical Systems (CPS) (DEIS) H2020 Project under Grant 732242, and in part by the LIVEBIO: Light-weight Verification for Synthetic Biology Project under Grant EPSRC EP/R043787/1
Probing the desert with fermion masses
We use the SU(3) SU(2) U(1) renormalization-group equations to place upper limits on the scale where new physics beyond the standard model must emerge. Our bounds rely solely on the structure of the renormalization-group equations and on the magnitudes of heavy-quark masses. For example, if Σm2q>~(450 GeV)2, new physics must be found below 105 GeV
Renormalization-group constraints in supersymmetric theories
We use the SU(3) SU(2) U(1) renormalization-group equations to constrain fermion masses and charged-scalar couplings in supersymmetric grand unified theories
Black Holes at the LHC
If the scale of quantum gravity is near a TeV, the LHC will be producing one
black hole (BH) about every second. The BH decays into prompt, hard photons and
charged leptons is a clean signature with low background. The absence of
significant missing energy allows the reconstruction of the mass of the
decaying BH. The correlation between the BH mass and its temperature, deduced
from the energy spectrum of the decay products, can test experimentally the
higher dimensional Hawking evaporation law. It can also determine the number of
large new dimensions and the scale of quantum gravity.Comment: 5 pages, 3 figures, submitted to PRL. Results presented at the Les
Houches Workshop "Physics at the TeV Colliders" (May 30, 2001) and the
"Avatars of M-Theory" conference, ITP at Santa Barbara (June 7, 2001),
http://online.itp.ucsb.edu/online/mtheory_c01/dimopoulo
Towards an Integrated Approach to Verification and Model-Based Testing in System Engineering
yesEngineering design in general and system design of embedded software have a direct impact on the final engineering product and the software implementation, respectively. Guaranteeing that the models utilised meet the specified requirements is beneficial in detecting misbehaviour and software flaws. This requires an integrated approach, combining verification and model-based testing methodology and notations and methods from system engineering and software engineering. In this paper, we propose a model-based approach integrating various notations utilised in the functional design of complex systems with formal verification and testing. We illustrate our approach on the cruise control system of an e-Bike case study
Echokardiograficzna ocena morfologii oraz funkcji lewej komory u młodych piłkarzy i wyczynowych biegaczy
Wstęp: Długotrwały wysiłek fizyczny powoduje zmiany adaptacyjne w budowie i funkcji mięśnia lewej komory, zależne od rodzaju i intensywności uprawianego sportu. Choć przeprowadzono
wiele badań opisujących echokardiograficzne odmienności serc sportowców, w dostępnym piśmiennictwie brakuje szczegółowej analizy zmian dotyczących zawodowego trenowania
piłki nożnej. Celem przedstawionego badania była ocena morfologicznych zmian związanych z wyczynowym uprawianiem sportu oraz porównanie zmierzonych echokardiograficznie wymiarów, masy i funkcji skurczowej lewej komory u biegaczy i piłkarzy.
Metody: Badaniami objęto 40 piłkarzy, 18 biegaczy długo- i średniodystansowych oraz 25 mężczyzn prowadzących siedzący tryb życia (grupa kontrolna). U wszystkich wykonano
badanie echokardiograficzne z oceną wymiarów lewej komory w prezentacji jedno- (M-mode) i dwuwymiarowej (2-D) oraz analizę przepływów za pomocą techniki fali doplerowskiej.
Wyniki: U osób uprawiających sport, w porównaniu z grupą kontrolną, stwierdzono statystycznie istotne zwiększenie wymiaru końcoworozkurczowego lewej komory, masy lewej komory (również po korekcji względem wzrostu, masy i powierzchni ciała), grubości przegrody międzykomorowej oraz frakcji wyrzutowej. Nie wykazano istotnych różnic w wartościach parametrów
echochokardiograficznych (z wyjątkiem wskaźnika masy lewej komory) między biegaczami a piłkarzami.
Wnioski: Przedstawione wyniki sugerują, że zwiększenie wymiarów lewej komory, podobne w obu grupach, stanowi fizjologiczną adaptację serca do wykonywanego wysiłku fizycznego
Experimental consequences of family unification
Theories of family unification predict four left-handed and four right-handed families of quarks and leptons, all with masses below 265 GeV. The lightest mirror quark has a mass of less than 140 GeV. All charged leptons are lighter than 55 GeV, and the lightest is below 40 GeV. All five new neutrinos have masses less than 40 GeV and contribute to the width of the Z0. We study the decays of these new families, and discuss rare processes such as μ→eγ. We also examine proton decay, and show that it can proceed into e+π0 at the observable but acceptable rate of 1032±1 yr
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