Spacetime could be simultaneously continuous and discrete in the same way that information can

There are competing schools of thought about the question of whether spacetime is fundamentally either continuous or discrete. Here, we consider the possibility that spacetime could be simultaneously continuous and discrete, in the same mathematical way that information can be simultaneously continuous and discrete. The equivalence of continuous and discrete information, which is of key importance in information theory, is established by Shannon sampling theory: of any bandlimited signal it suffices to record discrete samples to be able to perfectly reconstruct it everywhere, if the samples are taken at a rate of at least twice the bandlimit. It is known that physical fields on generic curved spaces obey a sampling theorem if they possess an ultraviolet cutoff. Most recently, methods of spectral geometry have been employed to show that also the very shape of a curved space (i.e., of a Riemannian manifold) can be discretely sampled and then reconstructed up to the cutoff scale. Here, we develop these results further, and we here also consider the generalization to curved spacetimes, i.e., to Lorentzian manifolds

Charm photoproduction at HERA: kt-factorization versus experimental data

We calculate the cross section of charm photoproduction at HERA collider in the framework of the kt-factorization QCD approach. Our analysis cover the inclusive charm production as well as charm and associated jet production processes. Both photon-gluon and gluon-gluon fusion mechanisms are taken into account. The unintegrated gluon densities in a proton and in a photon obtained from the full CCFM, from unified BFKL-DGLAP evolution equations as well as from the Kimber-Martin-Ryskin prescription are used. Our theoretical results are compared with the recent experimental data taken by the H1 and ZEUS collaborations at HERA. Special attention is put on the specific angular correlations which can provide unique information about non-collinear gluon evolution dynamics.Comment: 33 pages, 15 figures, 2 table

Prompt photon photoproduction at HERA in the k_T-factorization approach

We present calculations of the prompt photon photoproduction at HERA collider in the k_T-factorization approach. Both direct and resolved contributions are taken into account. The conservative error analisys is performed. The unintegrated parton densities in a proton and in a photon are determined using the Kimber-Martin-Ryskin prescription. We investigate both inclusive and associated with jet prompt photon photoproduction rates. In particular, we study the angular correlations between produced photon and hadronic jet in the transverse momentum plane which can provide a unique information about non-collinear evolution dynamics. We compare our theoretical predictions with recent experimental data taken by the H1 and ZEUS collaborations.Comment: 34 pages, 18 figure

Decomposing the Sources of Earnings Inequality Assessing the Role of Reallocation

This paper uses matched employer-employee data from the Longitudinal Employer Household Dynamics database to investigate the contribution of worker and firm reallocation to within industry changes in wage inequality between 1992 and 2003. We find that the entry and exit of firms and the sorting of workers and firms based on underlying worker "skills" are important determinants of changes in industry earnings distributions over time. Our results suggest that the underlying dynamics of earnings inequality are complex and are due to factors that cannot be measured in standard crosssectional data.

Schistosomiasis (mansoni) has a negative impact on serum levels of estradiol, progesterone and prolactin in the female baboon (Papio cynocephalus anubis)

To meet the growing concern for the well-being of laboratory animals, group-housing is now recommended for rats. The aim of the present study was to examine the effects of group-housing and relative weight within the group on feedingbehaviour in rats. Studies of the individual feeding behaviour of group-housed animals have been carried out in many farm animals. In these studies, when effects of group-housing and hierarchy on individual feeding behaviour are studied, theresults are often confounded by differences in age, body weight, genetic differences and earlier experience of the animal. All these factors were standardised in the present study. The individual meal patterns of 12 male Sprague-Dawley rats, ofthe same weight and age, housed singly were compared to their meal patterns after two weeks of housing in groups of three per cage, The feed intake and the feeding behaviour were recorded by computerised balances in combination with timelapse video recordings, during the group-housing period. Although when group-housed the rats made the same number of visits to the food cup as when housed singly, they ate more quickly, ate less per visit, and hence spent less time per dayeating. The increase in eating rate was significant for the rats assigned to be the medium weight or lightest in their groups but not for the rats designated to be heaviest in their groups, indicating that the relative weight of the rats had an effect on their eating behaviour

Transport Coefficients of Non-Newtonian Fluid and Causal Dissipative Hydrodynamics

A new formula to calculate the transport coefficients of the causal dissipative hydrodynamics is derived by using the projection operator method (Mori-Zwanzig formalism) in [T. Koide, Phys. Rev. E75, 060103(R) (2007)]. This is an extension of the Green-Kubo-Nakano (GKN) formula to the case of non-Newtonian fluids, which is the essential factor to preserve the relativistic causality in relativistic dissipative hydrodynamics. This formula is the generalization of the GKN formula in the sense that it can reproduce the GKN formula in a certain limit. In this work, we extend the previous work so as to apply to more general situations.Comment: 15 pages, no figure. Discussions are added in the concluding remarks. Accepted for publication in Phys. Rev.

High-accuracy sampling of saproxylic diversity indicators at regional scales with pheromones: The case of "Elater ferrugineus" (Coleoptera, Elateridae)

The rare beetle Elater ferrugineus was sampled at 47 sites in the county of Östergötland, Sweden by means of pheromone-baited traps to assess its value as an indicator species for hollow oak stands rich in rare saproxylic beetle species. In addition, Osmoderma eremita was also sampled with pheromone baits. These data were then compared against species survey data collected at the same sites by pitfall and window traps. Both species co-occur with many Red Listed saproxylic beetles, with E. ferrugineus being a somewhat better indicator for the rarest species. The conservation value of a site (measured as Red List points or number of Red Listed species) increased with the number of specimens of E. ferrugineus and O. eremita caught. Accuracy of sampling by means of pheromone trapping turned out to be radically different for the two model species. E. ferrugineus traps put out during July obtained full accuracy after only 6 days, whereas O. eremita traps needed to be out from early July to mid-August in order to obtain full accuracy with one trap per site. By using E. ferrugineus, or preferably both species, as indicator species, accuracy would increase and costs decrease for saproxylic biodiversity sampling, monitoring and identification of hotspots

Residue currents associated with weakly holomorphic functions

We construct Coleff-Herrera products and Bochner-Martinelli type residue currents associated with a tuple $f$ of weakly holomorphic functions, and show that these currents satisfy basic properties from the (strongly) holomorphic case, as the transformation law, the Poincar\'e-Lelong formula and the equivalence of the Coleff-Herrera product and the Bochner-Martinelli type residue current associated with $f$ when $f$ defines a complete intersection.Comment: 28 pages. Updated with some corrections from the revision process. In particular, corrected and clarified some things in Section 5 and 6 regarding products of weakly holomorphic functions and currents, and the definition of the Bochner-Martinelli type current

Bulk viscosity of superfluid neutron stars

The hydrodynamics, describing dynamical effects in superfluid neutron stars, essentially differs from the standard one-fluid hydrodynamics. In particular, we have four bulk viscosity coefficients in the theory instead of one. In this paper we calculate these coefficients, for the first time, assuming they are due to non-equilibrium beta-processes (such as modified or direct Urca process). The results of our analysis are used to estimate characteristic damping times of sound waves in superfluid neutron stars. It is demonstrated that all four bulk viscosity coefficients lead to comparable dissipation of sound waves and should be considered on the same footing.Comment: 11 pages, 1 figure, this version with some minor stylistic changes is published in Phys. Rev.