Application of product dioids for dead token detection in interval P-time event graphs

Linear description of interval P-time event graphs using a product idempotent semiring is proposed and applied to dead token detection. The dependence of dead token on initial condition is studied using residuation theory. Finally, the relationship with the spectral theory of matrices over product semirings is discusse

Modeling sea-salt aerosols in the atmosphere: 2. Atmospheric concentrations and fluxes

Atmospheric sea-salt aerosol concentrations are studied using both long-term observations and model simulations of Na+ at seven stations around the globe. Good agreement is achieved between observations and model predictions in the northern hemisphere. A stronger seasonal variation occurs in the high-latitude North Atlantic than in regions close to the equator and in high-latitude southern hemisphere. Generally, concentrations are higher for both boreal and austral winters. With the model, the production flux and removal flux at the atmosphere-ocean interface was calculated and used to estimate the global sea-salt budget. The flux also shows seasonal variation similar to that of sea-salt concentration. Depending on the geographic location, the model predicts that dry deposition accounts for 60–70% of the total sea-salt removed from the atmosphere while in-cloud and below-cloud precipitation scavenging accounts for about 1% and 28–39% of the remainder, respectively. The total amount of sea-salt aerosols emitted from the world oceans to the atmosphere is estimated to be in the vicinity of 1.17×1016 g yr−1. Approximately 99% of the sea-salt aerosol mass generated by wind falls back to the sea with about 1–2% remaining in the atmosphere to be exported from the original grid square (300×300 km). Only a small portion of that exported (∼4%) is associated with submicron particles that are likely to undergo long-range transport

Dendritic Spine Shape Analysis: A Clustering Perspective

Functional properties of neurons are strongly coupled with their morphology. Changes in neuronal activity alter morphological characteristics of dendritic spines. First step towards understanding the structure-function relationship is to group spines into main spine classes reported in the literature. Shape analysis of dendritic spines can help neuroscientists understand the underlying relationships. Due to unavailability of reliable automated tools, this analysis is currently performed manually which is a time-intensive and subjective task. Several studies on spine shape classification have been reported in the literature, however, there is an on-going debate on whether distinct spine shape classes exist or whether spines should be modeled through a continuum of shape variations. Another challenge is the subjectivity and bias that is introduced due to the supervised nature of classification approaches. In this paper, we aim to address these issues by presenting a clustering perspective. In this context, clustering may serve both confirmation of known patterns and discovery of new ones. We perform cluster analysis on two-photon microscopic images of spines using morphological, shape, and appearance based features and gain insights into the spine shape analysis problem. We use histogram of oriented gradients (HOG), disjunctive normal shape models (DNSM), morphological features, and intensity profile based features for cluster analysis. We use x-means to perform cluster analysis that selects the number of clusters automatically using the Bayesian information criterion (BIC). For all features, this analysis produces 4 clusters and we observe the formation of at least one cluster consisting of spines which are difficult to be assigned to a known class. This observation supports the argument of intermediate shape types.Comment: Accepted for BioImageComputing workshop at ECCV 201

(Quantum) Space-Time as a Statistical Geometry of Fuzzy Lumps and the Connection with Random Metric Spaces

We develop a kind of pregeometry consisting of a web of overlapping fuzzy lumps which interact with each other. The individual lumps are understood as certain closely entangled subgraphs (cliques) in a dynamically evolving network which, in a certain approximation, can be visualized as a time-dependent random graph. This strand of ideas is merged with another one, deriving from ideas, developed some time ago by Menger et al, that is, the concept of probabilistic- or random metric spaces, representing a natural extension of the metrical continuum into a more microscopic regime. It is our general goal to find a better adapted geometric environment for the description of microphysics. In this sense one may it also view as a dynamical randomisation of the causal-set framework developed by e.g. Sorkin et al. In doing this we incorporate, as a perhaps new aspect, various concepts from fuzzy set theory.Comment: 25 pages, Latex, no figures, some references added, some minor changes added relating to previous wor

Prospects for measuring the gravitational free-fall of antihydrogen with emulsion detectors

The main goal of the AEgIS experiment at CERN is to test the weak equivalence principle for antimatter. AEgIS will measure the free-fall of an antihydrogen beam traversing a moir\'e deflectometer. The goal is to determine the gravitational acceleration g for antihydrogen with an initial relative accuracy of 1% by using an emulsion detector combined with a silicon micro-strip detector to measure the time of flight. Nuclear emulsions can measure the annihilation vertex of antihydrogen atoms with a precision of about 1 - 2 microns r.m.s. We present here results for emulsion detectors operated in vacuum using low energy antiprotons from the CERN antiproton decelerator. We compare with Monte Carlo simulations, and discuss the impact on the AEgIS project.Comment: 20 pages, 16 figures, 3 table

Focal endoscopic mucosal resection before radiofrequency ablation is equally effective and safe compared with radiofrequency ablation alone for the eradication of Barrett's esophagus with advanced neoplasia

Endoscopic mucosal resection (EMR) is commonly performed before radiofrequency ablation (RFA) for nodular dysplastic Barrett’s esophagus (BE)

Multiplicity dependence of jet-like two-particle correlations in p-Pb collisions at sNN\sqrt{s_{NN}} = 5.02 TeV

Two-particle angular correlations between unidentified charged trigger and associated particles are measured by the ALICE detector in p-Pb collisions at a nucleon-nucleon centre-of-mass energy of 5.02 TeV. The transverse-momentum range 0.7 $< p_{\rm{T}, assoc} < p_{\rm{T}, trig} <$ 5.0 GeV/$c$ is examined, to include correlations induced by jets originating from low momen\-tum-transfer scatterings (minijets). The correlations expressed as associated yield per trigger particle are obtained in the pseudorapidity range $|\eta|<0.9$. The near-side long-range pseudorapidity correlations observed in high-multiplicity p-Pb collisions are subtracted from both near-side short-range and away-side correlations in order to remove the non-jet-like components. The yields in the jet-like peaks are found to be invariant with event multiplicity with the exception of events with low multiplicity. This invariance is consistent with the particles being produced via the incoherent fragmentation of multiple parton--parton scatterings, while the yield related to the previously observed ridge structures is not jet-related. The number of uncorrelated sources of particle production is found to increase linearly with multiplicity, suggesting no saturation of the number of multi-parton interactions even in the highest multiplicity p-Pb collisions. Further, the number scales in the intermediate multiplicity region with the number of binary nucleon-nucleon collisions estimated with a Glauber Monte-Carlo simulation.Comment: 23 pages, 6 captioned figures, 1 table, authors from page 17, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/161

Multi-particle azimuthal correlations in p-Pb and Pb-Pb collisions at the CERN Large Hadron Collider

Measurements of multi-particle azimuthal correlations (cumulants) for charged particles in p-Pb and Pb-Pb collisions are presented. They help address the question of whether there is evidence for global, flow-like, azimuthal correlations in the p-Pb system. Comparisons are made to measurements from the larger Pb-Pb system, where such evidence is established. In particular, the second harmonic two-particle cumulants are found to decrease with multiplicity, characteristic of a dominance of few-particle correlations in p-Pb collisions. However, when a $|\Delta \eta|$ gap is placed to suppress such correlations, the two-particle cumulants begin to rise at high-multiplicity, indicating the presence of global azimuthal correlations. The Pb-Pb values are higher than the p-Pb values at similar multiplicities. In both systems, the second harmonic four-particle cumulants exhibit a transition from positive to negative values when the multiplicity increases. The negative values allow for a measurement of $v_{2}\{4\}$ to be made, which is found to be higher in Pb-Pb collisions at similar multiplicities. The second harmonic six-particle cumulants are also found to be higher in Pb-Pb collisions. In Pb-Pb collisions, we generally find $v_{2}\{4\} \simeq v_{2}\{6\}\neq 0$ which is indicative of a Bessel-Gaussian function for the $v_{2}$ distribution. For very high-multiplicity Pb-Pb collisions, we observe that the four- and six-particle cumulants become consistent with 0. Finally, third harmonic two-particle cumulants in p-Pb and Pb-Pb are measured. These are found to be similar for overlapping multiplicities, when a $|\Delta\eta| > 1.4$ gap is placed.Comment: 25 pages, 11 captioned figures, 3 tables, authors from page 20, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/87

Intestinal Metaplasia Recurs Infrequently in Patients Successfully Treated for Barrett's Esophagus With Radiofrequency Ablation

Radiofrequency ablation (RFA) of Barrett’s esophagus (BE) is safe and effective in eradicating dysplasia and intestinal metaplasia and may reduce rates of esophageal adenocarcinoma (EAC). We assessed rates of and risk factors for disease recurrence after successful treatment of BE with RFA

Three-dimensional reconstruction of synapses and dendritic spines in the rat and ground squirrel hippocampus: New structural-functional paradigms for synaptic function

Published data are reviewed along with our own data on synaptic plasticity and rearrangements of synaptic organelles in the central nervous system. Contemporary laser scanning and confocal microscopy techniques are discussed, along with the use of serial ultrathin sections for in vivo and in vitro studies of dendritic spines, including those addressing relationships between morphological changes and the efficiency of synaptic transmission, especially in conditions of the long-term potentiation model. Different categories of dendritic spines and postsynaptic densities are analyzed, as are the roles of filopodia in originating spines. The role of serial ultrathin sections for unbiased quantitative stereological analysis and three-dimensional reconstruction is assessed. The authors data on the formation of more than two synapses on single mushroom spines on neurons in hippocampal field CA1 are discussed. Analysis of these data provides evidence for new paradigms in both the organization and functioning of synapses