To assess BAT activity in humans at a population level, infrared thermography (IRT) represents a safe, readily repeatable and affordable alternative to 18F-FDG-PET. Building upon a previously proposed method by our laboratory, we further refined the image computational algorithm to quantify BAT activation in the cervical-supraclavicular (C-SCV) region of healthy young men under thermo-neutral and cold exposure conditions. Additionally, we validated the whole-body calorimeter (WBC) in reliably measuring cold-induced thermogenesis. The temperature gradient between C-SCV-deltoid regions, and the corresponding difference in heat power output, increased upon cold air exposure relative to thermo-neutral conditions (by 74.88 %, p<0.0001; and by 71.34 %, p<0.0001 respectively). Resting and cumulative energy expenditure (EE) rose significantly (by 13.14 % and 9.12 % respectively, p=0.0001) while positive correlations between IRT measures and EE were found with cold air exposure (percentage change in heat power gradient between ROI and deltoid, cold air: r2 =0.29, p=0.026, Pearson's correlation). IRT and WBC can be used to study BAT activation. The refined algorithm allows for more automation and objectivity in IRT data analysis, especially under cold air exposures.
Felsenstein's classical model for Gaussian distributions on a phylogenetic tree is shown to be a toric variety in the space of concentration matrices. We present an exact semialgebraic characterization of this model, and we demonstrate how the toric structure leads to exact methods for maximum likelihood estimation. Our results also give new insights into the geometry of ultrametric matrices.
The paper deals with three issues. First we show a sufficient condition for a cylindrical local martingale to be a stochastic integral with respect to a cylindrical Wiener process. Secondly, we state an infinite dimensional version of the martingale problem of Stroock and Varadhan, and finally we apply the results to show that a weak existence plus uniqueness in law for deterministic initial conditions for an abstract stochastic evolution equation in a Banach space implies the strong Markov property.
Dnešní výklad Brownova pohybu vychází z předpokladu, že kapalina či plyn mají nespojitou strukturu a současné učebnice mu zpravidla nevěnují vice než několik řádků. Jak z fyzikálního, tak z pedagogického hlediska je však podstatně cennější (i zajímavější) historický postup, který k tvrzení, že látky sestávají z částic, dospívá jako k nevyhnutelnému důsledku existence tohoto jevu a jeho experimentálně zjištěných vlastností. Příspěvek rekapituluje fyzikálněhistorické souvislovsti a připomíná teoretické rozbory různých aspektů Brownova pohybu - provedené Abertem Einsteinem a Jeanem Perrinem -, jež po svém důvtipném a velice pracném Perrinově všestranném experimentálním ověření přivedly dvěma odlišnými cestami k nepochybnému závěru o částicové struktuře látek., From a physics and historical point of view, this article reviews the theoretical analyses of different aspects of Browninan motion carried out by Albert Einstein and Jean Perrin, which after experimental confirmation by Perrin, have led to two independent methods for the undoubte conclusion of the discrete structure of matter., Aleš Lacina., and Obsahuje seznam literatury