Using Non-Parametric Tests to Evaluate Traffic Forecasting Performance.

This paper proposes the use of a number of nonparametric comparison methods for evaluating traffic flow forecasting techniques. The advantage to these methods is that they are free of any distributional assumptions and can be legitimately used on small datasets. To demonstrate the applicability of these tests, a number of models for the forecasting of traffic flows are developed. The one-step-ahead forecasts produced are then assessed using nonparametric methods. Consideration is given as to whether a method is universally good or good at reproducing a particular aspect of the original series. That choice will be dictated, to a degree, by the user’s purpose for assessing traffic flow

Neutrino Mixing and Future Solar Neutrino Experiments

Possibilities of a model independent treatment of the data from future real-time solar neutrino experiments (SNO, Super-Kamiokande and others) are discussed. It is shown that in the general case of transitions of the initial solar $\nu_e$'s into $\nu_\mu$ and/or $\nu_\tau$ the total flux of initial 8B neutrinos and the $\nu_e$ survival probability can be determined directly from the experimental data. Lower bounds for the probability of transition of solar $\nu_e$'s into all possible sterile states are derived and expressed through measurable quantities.Comment: 3 pages. Compressed postscript file. If you prefer the uncompressed postscript file or a hardcopy of the paper, please write to [email protected]. Talk presented by S.M. Bilenky at TAUP93. DFTT 66/9

The construction and analysis of marker gene libraries

Marker genes for viruses are typically amplified from aquatic samples to determine whether specific viruses are present in the sample, or to examine the diversity of a group of related viruses. In this chapter, we will provide an overview of common methods used to amplify, clone, sequence, and analyze virus marker genes, and will focus our discussion on viruses infecting algae, bacteria, and heterotrophic flagellates. Within this chapter, we endeavor to highlight critical aspects and components of these methods. To this end, instead of providing a detailed experimental protocol for each of the steps involved in examining virus marker gene libraries, we have provided a few key considerations, recommendations, and options for each step. We conclude this chapter with a brief discussion of research on a major capsid protein (g20) of cyanomyoviruses using this work as a case study for polymerase chain reaction primer design and development. By building on the experience of numerous labs, this chapter should not only be useful to the new virus ecologist, but also serve as a valuable resource to established research groups

Neutron Path Length Correction of a 3He Spin Filter

Abstract3He neutron spin filters (NSF) have been widely used for polarized neutron instrumentation for worldwide neutron facilities. Here we report characterization of the two-dimensional neutron path variation of a 3He NSF when a large divergent, scattered neutron beam passes through the end windows of a cylindrical 3He cell. Path length variations of the transmission of the unpolarized neutrons through a 3He NSF and neutron polarization produced from a 3He NSF are characterized. We present a ray-tracing model to explain the path length variation and corresponding neutron transmission and neutron polarization variations, and compare the measured variations to those calculated from the model. Although the path length effect is not large, it should be corrected in the polarization efficiency correction software when a 3He NSF is used for SANS polarization analysis. The path length variation effect can be adopted to other types of neutron scattering spectrometers when using 3He NSFs

Ligand shell morphology of water-soluble mixed-monolayer protected gold nanoparticles

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2007.Includes bibliographical references (leaves 41-43).Nanoparticles comprise a versatile class of nanomaterials that consist of particles that have a characteristic length scale less than 100nm. They are on a similar length scale as many biological elements, so it is fitting that they are being used increasingly in biological systems for a variety of applications. Interesting properties of water-soluble metal nanoparticles that could lead to novel biological applications include bio-catalytic, sensing, and light scattering capabilities. We will present here the characterization of novel highly water-soluble gold nanoparticles that can be used as model systems to study the fundamental mechanisms of cellular uptake and intracellular trafficking.by Suelin Chen.S.M

Results of the MRI substudy of the intravenous magnesium efficacy in stroke trial

<p><b>Background and Purpose:</b>Although magnesium is neuroprotective in animal stroke models, no clinical benefit was confirmed in the Intravenous Magnesium Efficacy in Stroke (IMAGES) trial of acute stroke patients. The Magnetic Resonance in IMAGES (MR IMAGES) substudy investigated the effects of magnesium on the imaging surrogate outcome of infarct growth.</p> <p><b>Methods:</b> IMAGES trial patients in participating centers were randomized to receive either intravenous magnesium or placebo within 12 hours of stroke onset. Infarct growth was defined as volume difference between baseline diffusion-weighted imaging and day 90 fluid-attenuated inversion recovery image lesions. Patients who died were imputed the largest infarct growth observed.</p> <p><b>Results:</b> Among the 90 patients included in the primary analysis, there was no difference in infarct growth (median absolute growth, P=0.639; median percentage growth, P=0.616; proportion with any growth, P=0.212) between the 46 treated with magnesium and 44 with placebo. Infarct growth correlated with NIHSS score change from baseline to day 90. There was a trend showing baseline serum glucose correlated with infarct growth with magnesium treatment, but not in the placebo group. The mismatch frequency was reduced from 73% to 47% by increasing the mismatch threshold from >20% to >100% of core volume.</p> <p><b>Conclusions:</b> Infarct growth, confirmed here as a surrogate for clinical progression, was similar between magnesium and placebo treatment, paralleling the main IMAGES trial clinical outcomes. Glucose was a covariate for infarct growth with magnesium treatment. A more stringent mismatch threshold to define penumbra more appropriately would have excluded half of the patients in this 12-hour time window stroke study.</p&gt

Gravitomagnetic Effects in the Propagation of Electromagnetic Waves in Variable Gravitational Fields of Arbitrary-Moving and Spinning Bodies

Propagation of light in the gravitational field of self-gravitating spinning bodies moving with arbitrary velocities is discussed. The gravitational field is assumed to be "weak" everywhere. Equations of motion of a light ray are solved in the first post-Minkowskian approximation that is linear with respect to the universal gravitational constant $G$. We do not restrict ourselves with the approximation of gravitational lens so that the solution of light geodesics is applicable for arbitrary locations of source of light and observer. This formalism is applied for studying corrections to the Shapiro time delay in binary pulsars caused by the rotation of pulsar and its companion. We also derive the correction to the light deflection angle caused by rotation of gravitating bodies in the solar system (Sun, planets) or a gravitational lens. The gravitational shift of frequency due to the combined translational and rotational motions of light-ray-deflecting bodies is analyzed as well. We give a general derivation of the formula describing the relativistic rotation of the plane of polarization of electromagnetic waves (Skrotskii effect). This formula is valid for arbitrary translational and rotational motion of gravitating bodies and greatly extends the results of previous researchers. Finally, we discuss the Skrotskii effect for gravitational waves emitted by localized sources such as a binary system. The theoretical results of this paper can be applied for studying various relativistic effects in microarcsecond space astrometry and developing corresponding algorithms for data processing in space astrometric missions such as FAME, SIM, and GAIA.Comment: 36 pages, 1 figure, submitted to Phys. Rev.

A framework for bounding nonlocality of state discrimination

We consider the class of protocols that can be implemented by local quantum operations and classical communication (LOCC) between two parties. In particular, we focus on the task of discriminating a known set of quantum states by LOCC. Building on the work in the paper "Quantum nonlocality without entanglement" [BDF+99], we provide a framework for bounding the amount of nonlocality in a given set of bipartite quantum states in terms of a lower bound on the probability of error in any LOCC discrimination protocol. We apply our framework to an orthonormal product basis known as the domino states and obtain an alternative and simplified proof that quantifies its nonlocality. We generalize this result for similar bases in larger dimensions, as well as the "rotated" domino states, resolving a long-standing open question [BDF+99].Comment: 33 pages, 7 figures, 1 tabl