Competition between highway operators: can we expect toll differentiation?

Where there are alternative roads to the same destination, competition between profit maximizing road operators is possible. Tolls on such roads could perform two welfare enhancing functions; discouraging excessive driving and allocating drivers between roads. The second of these functions will typically require some roads to be more expensive to drive on, and to be less congested, than others. Bertrand equilibrium will not always peform this second function. It may fail to allocate the most impatient drivers to less congested roads, as it does not always deliver toll differentiation. The performance of this second function is dependent on the first. That is, whether or not competing roads will be differentiated by tolls and congestion, will depend in part on the importance of discouraging marginal drivers. The equilibrium will not generally be fully efficient, but will often provide efficiency gains over other decentralized options.congestion, road pricing, networks, market structure

Beyond-mean-field study of the possible "bubble" structure of 34Si

Recent self-consistent mean-field calculations predict a substantial depletion of the proton density in the interior of 34Si. In the present study, we investigate how correlations beyond the mean field modify this finding. The framework of the calculation is a particle-number and angular-momentum projected Generator Coordinate Method based on Hartree-Fock-Bogoliubov+Lipkin-Nogami states with axial quadrupole deformation. The parametrization SLy4 of the Skyrme energy density functional is used together with a density-dependent pairing energy functional. For the first time, the generator coordinate method is applied to the calculation of charge and transition densities. The impact of pairing correlations, symmetry restorations and shape mixing on the density profile is analyzed step by step. All these effects significantly alter the radial density profile, and tend to bring it closer to a Fermi-type density distribution.Comment: 9 pages, 7 figure

Long coherence times for edge spins

We show that in certain one-dimensional spin chains with open boundary conditions, the edge spins retain memory of their initial state for very long times. The long coherence times do not require disorder, only an ordered phase. In the integrable Ising and XYZ chains, the presence of a strong zero mode means the coherence time is infinite, even at infinite temperature. When Ising is perturbed by interactions breaking the integrability, the coherence time remains exponentially long in the perturbing couplings. We show that this is a consequence of an edge "almost" strong zero mode that almost commutes with the Hamiltonian. We compute this operator explicitly, allowing us to estimate accurately the plateau value of edge spin autocorrelator.Comment: 13 pages, 13 figures; references adde

Transport or Store? Synthesizing Flow-based Microfluidic Biochips using Distributed Channel Storage

Flow-based microfluidic biochips have attracted much atten- tion in the EDA community due to their miniaturized size and execution efficiency. Previous research, however, still follows the traditional computing model with a dedicated storage unit, which actually becomes a bottleneck of the performance of bio- chips. In this paper, we propose the first architectural synthe- sis framework considering distributed storage constructed tem- porarily from transportation channels to cache fluid samples. Since distributed storage can be accessed more efficiently than a dedicated storage unit and channels can switch between the roles of transportation and storage easily, biochips with this dis- tributed computing architecture can achieve a higher execution efficiency even with fewer resources. Experimental results con- firm that the execution efficiency of a bioassay can be improved by up to 28% while the number of valves in the biochip can be reduced effectively.Comment: ACM/IEEE Design Automation Conference (DAC), June 201

Temporal variability of the telluric sodium layer

The temporal variability of the telluric sodium layer is investigated by analyzing 28 nights of data obtained with the Colorado State University LIDAR experiment. The mean height power spectrum of the sodium layer was found to be well fit by a power law over the observed range of frequencies, 10 microhertz to 4 millhertz. The best fitting power law was found to be 10^\beta \nu^\alpha, with \alpha = -1.79 +/- 0.02 and \beta = 1.12 +/- 0.40. Applications to wavefront sensing require knowledge of the behavior of the sodium layer at kHz frequencies. Direct measurements at these frequencies do not exist. Extrapolation from low-frequency behavior to high frequencies suggests that this variability may be a significant source of error for laser-guide-star adaptive optics on large-aperture telescopes.Comment: 3 pages, 3 figures, accepted for publication in Optics Letter

Caractérisation Sédimentologique Et Minéralogique Des Formations Du Tertiaire-Quaternaire De La Région D’anyama Au Sud De La Côte d’Ivoire

Anyama is located on the onshore of the sedimentary basin of Côte d’Ivoire. It is to the east of the basin and the formations, particularly those dating back to the Quaternary may have been studied. Based on samples, collected from two drill holes (An1 and An2), each 114 m deep, a sedimentology and mineralogy characterization of Plio-Quaternary formations was carried out. The sedimentological study was assessed by taking account the lithology, the grain size, the transport model and the environment deposit of the sediments, the morphoscopy and the exoscopy of the quartz grain. The mineralogy study was made on clays through X-Ray Diffraction (XRD). Lithological characterization, revealed the presence of clay facies (kaolinite), sandy facies and mixed sediments, all covered with the earth bar. As for the size, it indicates coarse to medium sands with a positive asymmetry to almost positive, sands moderately classified to fairly classify. The relative mineralogy reveals the presence of silicon, aluminum and iron oxides. XRD indicates that quartz and kaolinite prevail and gypsum, rutile or anatase, illite and calcium sulfate hydrate are associated minerals

Mechanism Of Allosteric Modulation Of The Cys-Loop Receptors

The cys-loop receptor family is a major family of neurotransmitter-operated ion channels. They play important roles in fast synaptic transmission, controlling neuronal excitability, and brain function. These receptors are allosteric proteins, in that binding of a neurotransmitter to its binding site remotely controls the channel function. The cys-loop receptors also are subject to allosteric modulation by many pharmaceutical agents and endogenous modulators. By binding to a site of the receptor distinct from the neurotransmitter binding site, allosteric modulators alter the response of the receptors to their agonists. The mechanism of allosteric modulation is traditionally believed to be that allosteric modulators directly change the binding affinity of receptors for their agonists. More recent studies support the notion that these allosteric modulators are very weak agonists or antagonists by themselves. They directly alter channel gating, and thus change the distribution of the receptor across multiple different affinity states, indirectly influencing receptors\u27 sensitivity to agonists. There are two major locations of allosteric modulator binding sites. One is in subunit interfaces of the amino-terminal domain. The other is in the transmembrane domain close to the channel gating machinery. In this review, we also give some examples of well characterized allosteric binding pockets. © 2010 by the authors

A mammalian Wnt5a-Ror2-Vangl2 axis controls the cytoskeleton and confers cellular properties required for alveologenesis.

Alveolar formation increases the surface area for gas-exchange and is key to the physiological function of the lung. Alveolar epithelial cells, myofibroblasts and endothelial cells undergo coordinated morphogenesis to generate epithelial folds (secondary septa) to form alveoli. A mechanistic understanding of alveologenesis remains incomplete. We found that the planar cell polarity (PCP) pathway is required in alveolar epithelial cells and myofibroblasts for alveologenesis in mammals. Our studies uncovered a Wnt5a-Ror2-Vangl2 cascade that endows cellular properties and novel mechanisms of alveologenesis. This includes PDGF secretion from alveolar type I and type II cells, cell shape changes of type I cells and migration of myofibroblasts. All these cellular properties are conferred by changes in the cytoskeleton and represent a new facet of PCP function. These results extend our current model of PCP signaling from polarizing a field of epithelial cells to conferring new properties at subcellular levels to regulate collective cell behavior