The present paper studies the \textit{approximate value iteration} (AVI) algorithm for the average cost criterion with bounded costs and Borel spaces. It is shown the convergence of the algorithm and provided a performance bound assuming that the model satisfies a standard continuity-compactness assumption and a uniform ergodicity condition. This is done for the class of approximation procedures that can be represented by linear positive operators which give exact representation of constant functions and also satisfy certain continuity property. The main point is that these operators define transition probabilities on the state space of the controlled system. This has the following important consequences: (a) the approximating function is the average value of the target function with respect to the induced transition probability; (b) the approximation step in the AVI algorithm can be seen as a perturbation of the original Markov model; (c) the perturbed model inherits the ergodicity properties imposed on the original Markov model. These facts allow to bound the AVI algorithm performance in terms of the accuracy of the approximations given by this kind of operators for the primitive data model, namely, the one-step reward function and the system transition law. The bounds are given in terms of the supremum norm of bounded functions and the total variation norm of finite-signed measures. The results are illustrated with numerical approximations for a class of single item inventory systems with linear order cost, no set-up cost and no back-orders.
There are nine antirealist explanations of the success of science in the literature. I raise difficulties against all of them except the latest one, and then construct a pessimistic induction that the latest one will turn out to be problematic because its eight forerunners turned out to be problematic. This pessimistic induction is on a par with the traditional pessimistic induction that successful present scientific theories will be revealed to be false because successful past scientific theories were revealed to be false., V literatuře existuje devět antirealistických vysvětlení úspěchu vědy. Vyvolávám obtíže proti všem, s výjimkou posledního, a pak buduji pesimistickou indukci, že poslední z nich bude problematická, protože osm předchůdců se ukázalo jako problematické. Tato pesimistická indukce je na stejné úrovni s tradiční pesimistickou indukcí, že úspěšné současné vědecké teorie budou odhaleny jako nepravdivé, protože úspěšné minulé vědecké teorie byly odhaleny jako nepravdivé., and Seungbae Park
Motivated by applications to transition semigroups, we introduce the notion of a norming dual pair and study a Pettis-type integral on such pairs. In particular, we establish a sufficient condition for integrability. We also introduce and study a class of semigroups on such dual pairs which are an abstract version of transition semigroups. Using our results, we give conditions ensuring that a semigroup consisting of kernel operators has a Laplace transform which also consists of kernel operators. We also provide conditions under which a semigroup is uniquely determined by its Laplace transform.
A phycoerythrin-allophycocyanin (PE-AP) complex was obtained from intact phycobilisomes of the marine red alga Polysiphonia urceolata. Study of spectral properties and polypeptide components showed that the complex contains PE, phycocyanin, AP, and higher proportional linker proteins of the four groups present in intact phycobilisomes. and Li Sun, Shumei Wang.
PAM (pulse amplitude modulation) fluorometers can be used to estimate the electron transport rate (ETR) [μmol(e-) m-2 s-1] from photosynthetic yield determinations, provided the absorptance (Abtλ) of the photoorganism is known. The standard assumed value used for absorptance is 0.84 (leaf absorptance factor, AbtF). We described a reflectance-absorptancetransmittance (RAT) meter for routine experimental measurements of the actual absorptance of leaves. The RAT uses a red-green-blue (RGB) LED diode light source to measure absorptances at wavelengths suitable for use with PAM fluorometers and infrared gas analysers. Results using the RAT were compared to Abtλ spectra using a Taylor integrating sphere on bird’s nest fern (Asplenium nidus), banana, Doryanthes excelsa, Kalanchoe daigremontiana, and sugarcane. Parallel venation had no significant effect upon Abt465 in banana, Doryanthes, a Dendrobium orchid, pineapple, and sugarcane, but there was a slight difference in the case of the fern A. nidus. The average Abt465 (approximately 0.96) and Abt625 (approximately 0.89) were approximately 14% and 6% higher than the standard value (AbtF = 0.84). The PAR-range Abt400-700 was only approximately 5% higher than the standard value (approximately 0.88) based on averaged absorptance from the blue, green, and red light data and from where the RGB-diode was used as a ‘white’ light source. In some species, absorptances at blue and red wavelengths are quite different (e.g. water lily). Reflectance measurements of leaves using the RAT would also be useful for remote sensing studies., R. J. Ritchie, J. W. Runcie., and Obsahuje bibliografii
This article discusses the issues raised by James M. Robertson in his review of Joseph Grim Feinberg’s The Paradox of Authenticity: Folklore Performance in Post-Communist Slovakia, which appeared in Contradictions (2019, no. 2). Focusing on the nature and form of a re-politicized folklore, the article argues that to make full sense of the question of authenticity in a modern folkloric movement, authenticity must be seen against the broader backdrop of the alienation inherent to consumer capitalist society. Folklore, it concludes, can become re-politicized by emphasizing people’s participation in art as part of a broader countercultural movement that challenges the consumerist paradigm.
Chronic sojourn in hypoxic environment results in the structural remodeling of peripheral pulmonary arteries and pulmonary hypertension. We hypothesize that the pathogenesis of changes in pulmonary vascular structure is related to the increase of radical production induced by lung tissue hypoxia. Hypoxia primes alveolar macrophages to produce more hydrogen peroxide. Furthermore, the increased release of oxygen radicals by other hypoxic lung cells cannot be excluded. Several recent reports demonstrate the oxidant damage of lungs exposed to chronic hypoxia. The production of nitric oxide is high in animals with hypoxic pulmonary hypertension and the serum concentration of nitrotyrosine (radical product of nitric oxide and superoxide interaction) is also increased in chronically hypoxic rats. Antioxidants were shown to be effective in the prevention of hypoxia induced pulmonary hypertension. We suppose that the mechanism by which the radicals stimulate of the vascular remodeling is due to their effect on the metabolism of vascular wall matrix proteins. Non-enzymatic protein alterations and/or activation of collagenolytic matrix metalloproteinases may also participate. The presence of low-molecular weight cleavage products of matrix proteins stimulates the mesenchymal proliferation in the wall of distal pulmonary arteries. Thickened and less compliant peripheral pulmonary vasculature is then more resistant to the blood flow and the hypoxic pulmonary hypertension is developed., J. Herget, J. Wilhelm, J. Novotná, A. Eckhardt, R. Vytášek, L. Mrázková, M. Ošťádal., and Obsahuje bibliografii
In this paper is proved a weighted inequality for Riesz potential similar to the classical one by D. Adams. Here the gain of integrability is not always algebraic, as in the classical case, but depends on the growth properties of a certain function measuring some local potential of the weight.