A Scalable Tile Map Service for Distributing Dynamic Choropleth Maps

In this paper we propose a solution to several key limitations of current web based mapping systems: slow rendering speeds and the restriction of online map viewing to a small number of areal units as well as a limited number of users. Our approach is implemented as a Scalable Tile Map Service that distributes dynamic choropleth maps in real-time through a new caching methodology. This new Map Service lays the foundation for advances in web based applications reliant on dynamic map rendering such as emergency management systems and interactive exploratory spatial data analysis. We present the results of an empirical illustration in which this new methodology is used to facilitate collaborative decision making by visualizing spatial outcomes of simulation results on the fly.

Self-Organizing Maps and the US Urban Spatial Structure

This article considers urban spatial structure in US cities using a multi- dimensional approach. We select six key variables (commuting costs, den- sity, employment dispersion/concentration, land-use mix, polycentricity and size) from the urban literature and define measures to quantify them. We then apply these measures to 359 metropolitan areas from the 2000 US Census. The adopted methodological strategy combines two novel techniques for the social sciences to explore the existence of relevant pat- terns in such multi-dimensional datasets. Geodesic self-organizing maps (SOM) are used to visualize the whole set of information in a meaningful way, while the recently developed clustering algorithm of the max-p is applied to draw boundaries within the SOM and analyze which cities fall into each of them. JEL C45, R0, R12, R14. Keywords Urban spatial structure, self-organizing maps, US metropolitan areas

Effects of Irregular Topology in Spherical Self-Organizing Maps

We explore the effect of different topologies on properties of self-organizing maps (SOM). We suggest several diagnostics for measuring topology-induced errors in SOM and use these in a comparison of four different topologies. The results show that SOM is less sensitive to localized irregularities in the network structure than the literature may otherwise suggest. Further, the results support the use of spherical topologies as a solution to the boundary problem in traditional SOM.

The Importance of Lens Galaxy Environments

While many strong gravitational lens galaxies are suspected to lie in groups or clusters of galaxies, environmental effects in lens models are often unconstrained and sometimes ignored. We show that this creates significant biases in a variety of lensing applications, by creating mock lenses associated with each of 13 galaxies in a realistic model group, and then analyzing them with standard techniques. We find that standard models of double lenses, which neglect environment, grossly overestimate the ellipticity of the lens galaxy (de/e~0.5) and the Hubble constant (dh/h~0.22). Standard models of quad lenses, which approximate the environment as a tidal shear, recover the ellipticity reasonably well (|de/e|<~0.24) but overestimate the Hubble constant (dh/h~0.15), and have significant (~30%) errors in the millilensing analyses used to constrain the amount of substructure in dark matter halos. For both doubles and quads, standard models slightly overestimate the velocity dispersion of the lens galaxy (d(sigma)/sigma~0.06), and underestimate the magnifications of the images (d(mu)/mu ~ -0.25). Standard analyses of lens statistics overestimate Omega_Lambda (by 0.05-0.14), and underestimate the ratio of quads to doubles (by a factor of 2). These biases help explain some long-standing puzzles (such as the high observed quad/double ratio), but aggravate others (such as the low value of H_0 inferred from lensing). Most of the biases are caused by neglect of the convergence from the mass associated with the environment, but additional uncertainty is introduced by neglect of higher-order terms. Fortunately, we show that directly observing and modeling lens environments should make it possible to remove the biases and reduce the uncertainties associated with environments to the few percent level. (Abridged)Comment: 14 emulateapj pages; accepted in Ap

Coherent Population Trapping of Electron Spins in a Semiconductor

In high-purity n-type GaAs under strong magnetic field, we are able to isolate a lambda system composed of two Zeeman states of neutral-donor bound electrons and the lowest Zeeman state of bound excitons. When the two-photon detuning of this system is zero, we observe a pronounced dip in the excited-state photoluminescence indicating the creation of the coherent population-trapped state. Our data are consistent with a steady-state three-level density-matrix model. The observation of coherent population trapping in GaAs indicates that this and similar semiconductor systems could be used for various EIT-type experiments.Comment: 5 pages, 4 figures replaced 6/25/2007 with PRL versio

Quantum Correlations in Two-Boson Wavefunctions

We present the Schmidt decomposition for arbitrary wavefunctions of two indistinguishable bosons, extending the recent studies of entanglement or quantum correlations for two fermion systems [J. Schliemann et al., Phys. Rev. B {\bf 63}, 085311 (2001) and quant-ph/0012094]. We point out that the von Neumann entropy of the reduced single particle density matrix remains to be a good entanglement measure for two identical particles.Comment: in press at Phys. Rev.

Infection Regulates Pro-Resolving Mediators that Lower Antibiotic Requirements

Underlying mechanisms for how bacterial infections contribute to active resolution of acute inflammation are unknown. Here, we performed exudate leukocyte trafficking and mediator-metabololipidomics of murine peritoneal Escherichia coli (E. coli) infections with temporal identification of pro-inflammatory (prostaglandins and leukotrienes) and specialized pro-resolving mediators (SPM). In self-resolving E. coli exudates ($10^5$ CFU), the dominant SPM identified were resolvin (Rv) D5 and protectin D1 (PD1), which at 12 h were significantly greater than levels in exudates from higher titer E. coli ($10^7$ CFU) challenged mice. Germ-free mice displayed endogenous RvD1 and PD1 levels higher than in conventional mice. RvD1 and RvD5 (ng/mouse) each reduced bacterial titers in blood and exudates, E. coli-induced hypothermia and increased survival, demonstrating the first actions of RvD5. With human polymorphonuclear neutrophils (PMN) and macrophages, RvD1, RvD5, and PD1 each directly enhanced phagocytosis of E. coli, and RvD5 counter-regulated a panel of pro-inflammatory genes, including NF-κB and TNF-α. RvD5 activated the RvD1 receptor, GPR32, to enhance phagocytosis. With self-limited E. coli infections, RvD1 and the antibiotic ciprofloxacin accelerated resolution, each shortening resolution intervals (Ri). Host-directed RvD1 actions enhanced ciprofloxacin’s therapeutic actions. In $10^7$ CFU E. coli infections, SPM (RvD1, RvD5, PD1) together with ciprofloxacin also heightened host antimicrobial responses. In skin infections, SPM enhanced vancomycin clearance of Staphylococcus aureus. These results demonstrate that specific SPM are temporally and differentially regulated during infections and that they are anti-phlogistic, enhance containment and lower antibiotic requirements for bacterial clearance

Ефективність антихелікобактерних комплексів у хворих на пептичну виразку, асоційовану з хелікобактеріозом і оцінка їх впливу на стан слизового бар’єра гастродуоденальної зони

Мета - вивчити у хворих на пептичну виразку (ПВ), асоційовану з хелікобактеріозом (HP), терапевтичну ефективність антихелікобактерних комплексів (АХБК), а також їх влив на стан метаболічних процесів у слизовому бар’єрі гастродуоденальної зони

High-frequency pressure variations in the vicinity of a surface CO2 flux chamber

We report measurements of 2 Hz pressure fluctuations at and below the soil surface in the vicinity of a surface-based CO2 flux chamber. These measurements were part of a field experiment to examine the possible role of pressure pumping due to atmospheric pressure fluctuations on measurements of surface fluxes of CO2. Under the moderate wind speeds, warm temperatures, and dry soil conditions present at the time of our observations, the chamber had no effect on the pressure field in its near vicinity that could be detected above the level of natural pressure fluctuations in the vicinity. At frequencies at or \u3c2 Hz, pressure fluctuations easily penetrated the soil to depths of several cm with little attenuation. We conclude that the presence of the chamber does not introduce pressure perturbations that lead to biases in measurements of surface fluxes of CO2