mGPT: A Probabilistic Planner Based on Heuristic Search

We describe the version of the GPT planner used in the probabilistic track of the 4th International Planning Competition (IPC-4). This version, called mGPT, solves Markov Decision Processes specified in the PPDDL language by extracting and using different classes of lower bounds along with various heuristic-search algorithms. The lower bounds are extracted from deterministic relaxations where the alternative probabilistic effects of an action are mapped into different, independent, deterministic actions. The heuristic-search algorithms use these lower bounds for focusing the updates and delivering a consistent value function over all states reachable from the initial state and the greedy policy

Tobacco Spending and its Crowd-Out of Other Goods

Smoking is an expensive habit. Smoking households spend, on average, more than $1000 annually on cigarettes. For households in which some members smoke, smoking expenditures crowd-out other purchases, which may affect other household members, as well as the smoker. We empirically analyze how expenditures on tobacco crowd out consumption of other goods, estimating the patterns of substitution between tobacco products and other expenditures. We use the Consumer Expenditure Survey (1995 to 2001), which we complement with regional price data, and state cigarette prices. We estimate a consumer demand system of expenditures on cigarettes, food, alcohol, housing, apparel, transportation, medical care and controls for socio-economic variables and other sources of observable heterogeneity. Descriptive data indicate that, compared to non-smokers, smokers spend less on housing. Results from the demand system indicate that as the price of cigarettes rises, households increase the quantity of food purchased, and, in some samples, reduce the quantity of apparel and housing purchased.

Kinetics of Particles Adsorption Processes Driven by Diffusion

The kinetics of the deposition of colloidal particles onto a solid surface is analytically studied. We take into account both the diffusion of particles from the bulk as well as the geometrical aspects of the layer of adsorbed particles. We derive the first kinetic equation for the coverage of the surface (a generalized Langmuir equation) whose predictions are in agreement with recent simulation results where diffusion of particles from the bulk is explicitly considered.Comment: 4 page

Vortices in simulations of solar surface convection

We report on the occurrence of small-scale vortices in simulations of the convective solar surface. Using an eigenanalysis of the velocity gradient tensor, we find the subset of high vorticity regions in which the plasma is swirling. The swirling regions form an unsteady, tangled network of filaments in the turbulent downflow lanes. Near-surface vertical vortices are underdense and cause a local depression of the optical surface. They are potentially observable as bright points in the dark intergranular lanes. Vortex features typically exist for a few minutes, during which they are moved and twisted by the motion of the ambient plasma. The bigger vortices found in the simulations are possibly, but not necessarily, related to observations of granular-scale spiraling pathlines in "cork animations" or feature tracking.Comment: 11 pages, 13 figures, accepted for publication in A&A, complementary movies at http://www.mps.mpg.de/homes/moll/strudel/papermovies

Evidence of photospheric vortex flows at supergranular junctions observed by FG/SOT (Hinode)

Twisting motions of different nature are observed in several layers of the solar atmosphere. Chromospheric sunspot whorls and rotation of sunspots or even higher up in the lower corona sigmoids are examples of the large scale twisted topology of many solar features. Nevertheless, their occurrence at large scale in the quiet photosphere has not been investigated. The present study reveals the existence of vortex flows located at the supergranular junctions of the quiet Sun. We use a 1-hour and a 5-hour time series of the granulation in Blue continuum and G-band images from FG/SOT to derive the photospheric flows. A feature tracking technique called Balltracking is performed to track the granules and reveal the underlying flow fields. In both time series we identify long-lasting vortex flow located at supergranular junctions. The first vortex flow lasts at least 1 hour and is ~20-arcsec-wide (~15.5 Mm). The second vortex flow lasts more than 2 hours and is ~27-arcsec-wide (~21 Mm).Comment: 4 pages, 10 figure

A Note on the Spectrum of Composition Operators on Spaces of Real Analytic Functions

[EN] In this paper the spectrum of composition operators on the space of real analytic functions is investigated. In some cases it is completely determined while in some other cases it is only estimated.The research of the authors was partially supported by MEC and FEDER Project MTM2013-43540-P and the work of of Bonet by the Grant GV Project Prometeo II/2013/013. The research of Domanski was supported by National Center of Science, Poland, Grant No. DEC-2013/10/A/ST1/00091.Bonet Solves, JA.; Domanski, P. (2017). A Note on the Spectrum of Composition Operators on Spaces of Real Analytic Functions. Complex Analysis and Operator Theory. 11(1):161-174. https://doi.org/10.1007/s11785-016-0589-5S161174111Belitskii, G., Lyubich, Y.: The Abel equation and total solvability of linear functional equations. Studia Math. 127, 81–97 (1998)Belitskii, G., Lyubich, Y.: The real analytic solutions of the Abel functional equation. Studia Math. 134, 135–141 (1999)Belitskii, G., Tkachenko, V.: One-Dimensional Functional Equations. Springer, Basel (2003)Belitskii, G., Tkachenko, V.: Functional equations in real analytic functions. Studia Math. 143, 153–174 (2000)Bonet, J., Domański, P.: Power bounded composition operators on spaces of analytic functions. Collect. Math. 62, 69–83 (2011)Bonet, J., Domański, P.: Hypercyclic composition operators on spaces of real analytic fucntions. Math. Proc. Cambridge Phil. Soc. 153, 489–503 (2012)Bonet, J., Domański, P.: Abel’s functional equation and eigenvalues of composition operators on spaces of real analytic functions. Integr. Equ. Oper. Theor. 81, 455–482 (2015). doi: 10.1007/s00020-014-2175-4Cartan, H.: Variétés analytiques réelles et variétés analytiques complexes. Bull. Soc. Math. France 85, 77–99 (1957)Domański, P.: Notes on real analytic functions and classical operators, Topics in Complex Analysis and Operator Theory (Winter School in Complex Analysis and Operator Theory, Valencia, February 2010), Contemporary Math. 561 (2012) 3–47. Amer. Math. Soc, Providence (2012)Domański, P., Goliński, M., Langenbruch, M.: A note on composition operators on spaces of real analytic functions. Ann. Polon. Mat. 103, 209–216 (2012)Domański, P., Langenbruch, M.: Composition operators on spaces of real analytic functions. Math. Nachr. 254–255, 68–86 (2003)Domański, P., Langenbruch, M.: Coherent analytic sets and composition of real analytic functions. J. reine angew. Math. 582, 41–59 (2005)Domański, P., Langenbruch, M.: Composition operators with closed image on spaces of real analytic functions. Bull. Lond. Math. Soc. 38, 636–646 (2006)Domański, P., Vogt, D.: The space of real analytic functions has no basis. Studia Math. 142, 187–200 (2000)Hörmander, L.: An Introduction to Complex Analysis in Several Variables. North Holland, Amsterdam (1986)Meise, R., Vogt, D.: Introduction to Functional Analysis. Clarendon, Oxford (1997)Smajdor, W.: On the existence and uniqueness of analytic solutions of the functional equation $$\varphi (z)=h(z,\varphi [f(z)])$$ φ ( z ) = h ( z , φ [ f ( z ) ] ) . Ann. Polon. Math. 19, 37–45 (1967

Serum S-adenosylmethionine, but not methionine, increases in response to overfeeding in humans

Background: Plasma concentration of the methyl donor S-adenosylmethionine (SAM) is linearly associated with body mass index (BMI) and fat mass. As SAM is a high-energy compound and a sensor of cellular nutrient status, we hypothesized that SAM would increase with overfeeding. Methods: Forty normal to overweight men and women were overfed by 1250 kcal per day for 28 days. Results: Serum SAM increased from 106 to 130 nmol/l (P=0.006). In stratified analysis, only those with weight gain above the median (high-weight gainers; average weight gain 3.9±0.3 kg) had increased SAM (+42%, P=0.001), whereas low-weight gainers (weight gain 1.5±0.2 kg) did not (Pinteraction=0.018). Overfeeding did not alter serum concentrations of the SAM precursor, methionine or the products, S-adenosyl-homocysteine and homocysteine. The SAM/SAH (S-adenosylhomocysteine) ratio was unchanged in the total population, but increased in high-weight gainers (+52%, P=0.006, Pinteraction =0.005). Change in SAM correlated positively with change in weight (r=0.33, P=0.041) and fat mass (r=0.44, P=0.009), but not with change in protein intake or plasma methionine, glucose, insulin or low-density lipoprotein (LDL)-cholesterol. Conclusion: Overfeeding raised serum SAM in proportion to the fat mass gained. The increase in SAM may help stabilize methionine levels, and denotes a responsiveness of SAM to nutrient state in humans. The role of SAM in human energy metabolism deserves further attention.A K Elshorbagy, F Jernerén, D Samocha-Bonet, H Refsum and L K Heilbron

Histogram Reweighting Method for Dynamic Properties

The histogram reweighting technique, widely used to analyze Monte Carlo data, is shown to be applicable to dynamic properties obtained from Molecular Dynamics simulations. The theory presented here is based on the fact that the correlation functions in systems in thermodynamic equilibrium are averages over initial conditions of functions of the trajectory of the system in phase-space, the latter depending on the volume, the total number of particles and the classical Hamiltonian. Thus, the well-known histogram reweighting method can almost straightforwardly be applied to reconstruct the probability distribution of initial states at different thermodynamic conditions, without extra computational effort. Correlation functions and transport coefficients are obtained with this method from few simulation data sets.Comment: 4 pages, 3 figure