Revisiting the nonplace Urban Realm: Have we come full circle?

Melvin Webber's seminal papers of 1963/64, which posited the arrival of a Nonplace Urban Realm and called upon planners to abandon their obsession with space, have proved highly prescient: metropolitan areas have deconcentrated and spread as he suggested, and the arrival of the informational age further reinforces these trends by creating a spaceless economy. But urban agglomeration economies do continue to operate, and traditional urban nodes will remain important in the new space‐economy.     

The rank one mixed μ problem and ‘kharitonov-type’ analysis

The general mixed μ problem has been shown to be NP hard, so that the exact solution of the general problem is computationally intractable, except for small problems. In this paper we consider not the general problem, but a particular special case of this problem, the rank one mixed μ problem. We show that for this case the mixed μ problem is equivalent to its upper bound (which is convex), and it can in fact be computed easily (and exactly). This special case is shown to be equivalent to the so-called ‘affine parameter variation’ problem (for a polynomial with perturbed coefficients) which has been examined in detail in the literature, and for which several celebrated ‘Kharitonov-type’ results have been proven.     

Finances and Well-Being: A Dynamic Equilibrium Model of Resources.

This study of 513 Dutch farmers tested a dynamic equilibrium model of resources (an extension of the conservation of resources theory; S. E. Hobfoll, 1989, 1998, 2001). With structural equation modeling, the advantages of a 3-wave longitudinal design were comprehensively used, such as addressing bidirectional causal effects and within-individual vs. between-individual change. This allowed for a careful analysis of the management function of resources in the stress process. Results showed that well-being had stronger within-person stability than finances. Increased levels of financial problems temporarily increased psychological distress but not self-reported illness. Conversely, farmers with higher stable baselines of psychological distress also had higher baselines of self-reported illness and experienced more negative changes in their financial situation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Simulation of the VVER-1000 pump start-up experiment of the OECD V1000CT benchmark with CATHARE and TRAC-PF1

In the framework of joint effort between the Nuclear Energy Agency (NEA) of OECD, the United States Department of Energy (US DOE), and the Commissariat a l'Energie Atomique (CEA), France a coupled three-dimensional (3D) thermal-hydraulics/neutron kinetics benchmark for VVER-1000 was defined. The benchmark consists of calculation of a pump start-up experiment labelled V1000CT-1 (Phase 1), as well as a vessel mixing experiment and main steam line break (MSLB) transient labelled V1000CT-2 (Phase 2), respectively. The reference nuclear plant is Kozloduy-6 in Bulgaria. The overall objective is to assess computer codes used in the analysis of VVER-1000 reactivity transients. A specific objective is to assess the vessel mixing models used in system codes. Plant data are available for code validation consisting of one experiment of pump start-up (V1000CT-1) and one experiment of steam generator isolation (V1000CT-2). The validated codes can be used to calculate asymmetric MSLB transients involving similar mixing patterns. This paper summarizes a comparison of CATHARE and TRAC-PF1 system code results for V1000CT-1, Exercise 1, which is a full plant point kinetics simulation of a reactor coolant system (RCS) pump start-up experiment. The reference plant data include integral and sector average parameters. The comparison is made from the point of view of vessel mixing and full system simulation. CATHARE used a six-sector multiple 1D vessel thermal-hydraulic model with cross flows and TRAC used a six-sector, 18-channel coarse-mesh 3D vessel model. Good agreement in terms of integral parameters and inter-loop mixing is observed.     

Development and adoption of measures for increasing the safety of power-generating units of nuclear power plants with RBMK reactors in 1986–2005

The basic stages and directions of upgrading and reconstruction of the power-generating units of nuclear power plants with RBMK reactors over a period of 20 yr since the Chernobyl accident are reflected in this paper. The greatest amount of work was done in 1986–1990 on all units with RBMK-1000 and-1500 reactors which were operating at that time in the USSR. The purpose of the upgrade was to improve the neutron-physical characteristics of the reactor cores, increase the response speed of the safety and control system and decrease the positive effect of water outflow from the cooling loop of this system, increase the flow capacity of the systems performing emergency discharge of the steam-gas mixture from the reactor, and improve the basic operating documentation. The subsequent stages of the upgrading and reconstruction concerned mainly the first-generation power-generating units (Nos. 1 and 2 units of the Leningrad and Kursk nuclear power plants). These works were performed to make the power-generating units conform to the requirements of the modern normative documents on safety and allow for the possibility of these units to remain in operation after the nominal 30-yr service life has been exhausted. __________ Translated from Atomnaya énergiya, Vol. 100, No. 4, pp. 312–320, April, 2006.     

Efficient approximation to calculate time delay and dispersion in linearly chirped periodical microphotonic structures

The Bloch mode propagation through the chirped periodical structure is defined by its local dispersion relation. In a slowly varying structure its time delay is the integral of the local inverse group velocity along the propagation direction. The integration can be strongly simplified for linearly chirped structures if the assumption is made that the local dispersion relation is just a scaled and shifted version of the dispersion relation at the input. This assumption leads to exact solutions for the structures with locally uniaxial deformation and provides a good approximation for arbitrary structures with small chirps. The approach is demonstrated for high index contrast chirped Bragg mirrors and complicated photonic crystal waveguide structures, including coupled waveguides and a slow group velocity waveguide.     

Remote sensing of species mixtures in conifer plantations using LiDAR height and intensity data

In even-aged, single species conifer plantations LiDAR height data can be modelled to provide accurate estimates of tree height and volume. However, it is apparent that growth models developed for single species stands are not directly transferable to a more general situation of mixed species plantations. This paper evaluates the ability of small footprint, dual-return, pulsed airborne LiDAR data to estimate the proportion of the productive species when mixed with a nurse crop in closed canopy plantations. A study area located in Galloway Forest District in Scotland is used as an example of Lodgepole pine and Sitka spruce mixed plantation; this area contains good examples of a wide range of pure and mixed species plantation types. Three species groups are studied: areas of pure Sitka spruce, areas of pure Lodgepole pine and areas where the two species have been planted together. Two approaches are assessed for detection of plantation mixtures: the first uses LiDAR intensity data to separate spruce and pine species and the second uses LiDAR-derived canopy density measures, coefficient of variation, skewness, percent of ground returns (which provides a measure of canopy openness) and the mean canopy height, which enables areas with height variations to be identified. From analysis of LiDAR data extracted from 54 study plots using logistic regression, the coefficient of variation and LiDAR intensity data provide the most useful predictors of the proportion of spruce in a pine/spruce mixture with coefficients of determination (R²) of 0.914 and 0.930 respectively. The method could be developed as a mapping tool, which in combination with existing inventory data should help to improve timber volume forecasting for mixed species even-aged plantations.     

Advanced modulation formats for more robust optical transmission systems

Interest in advanced modulation formats for optical communication systems has so far experienced two major waves. The first one was motivated by the potential to enhance receiver sensitivity of thermal noise-limited systems using coherent detection in combination with phase shift keying. It ended with the advent of optical amplification, enabling high sensitivities together with polarization insensitive, simple and stable direct detection. The second wave is still rolling, fueled by the potential of advanced modulation formats to increase robustness of optical transmission systems against signal distortions. Due to performance limitations given by direct detection and nonlinear effects in the transmission fiber, it is not decided yet, whether there will be widespread application in carrier networks.     

Width-restricted layering of acyclic digraphs with consideration of dummy nodes

This paper deals with the problem of finding graph layerings restricted to a given maximal width. However, other than previous approaches for width-restricted layering, we take into account the space for dummy nodes, which are introduced by edges crossing a layer. The main result is that the problem of finding a width-restricted layering under consideration of dummy nodes is NP-complete even when all regular nodes have the same constant width and all dummy nodes have the same constant width.     

Stimulatory effects of tannins and cholic acid on tryptic hydrolysis of proteins: Ecological implications

The biochemical basis for considering tannins as digestion inhibitors has been reexamined. Both stimulatory and inhibitory effects of tannins on tryptic hydrolysis are reported. We show how stimulation may result from tannin-induced structural changes in the substrate protein, effectively denaturing it. The surfactant and bile constituent cholic acid also produced similar stimulatory effects. These results have considerable implications for normal digestive physiology as well as for the impact of tannins on argicultural and natural herbivore populations.