Prioritized Metric Structures and Embedding

Metric data structures (distance oracles, distance labeling schemes, routing schemes) and low-distortion embeddings provide a powerful algorithmic methodology, which has been successfully applied for approximation algorithms \cite{llr}, online algorithms \cite{BBMN11}, distributed algorithms \cite{KKMPT12} and for computing sparsifiers \cite{ST04}. However, this methodology appears to have a limitation: the worst-case performance inherently depends on the cardinality of the metric, and one could not specify in advance which vertices/points should enjoy a better service (i.e., stretch/distortion, label size/dimension) than that given by the worst-case guarantee. In this paper we alleviate this limitation by devising a suit of {\em prioritized} metric data structures and embeddings. We show that given a priority ranking $(x_1,x_2,\ldots,x_n)$ of the graph vertices (respectively, metric points) one can devise a metric data structure (respectively, embedding) in which the stretch (resp., distortion) incurred by any pair containing a vertex $x_j$ will depend on the rank $j$ of the vertex. We also show that other important parameters, such as the label size and (in some sense) the dimension, may depend only on $j$. In some of our metric data structures (resp., embeddings) we achieve both prioritized stretch (resp., distortion) and label size (resp., dimension) {\em simultaneously}. The worst-case performance of our metric data structures and embeddings is typically asymptotically no worse than of their non-prioritized counterparts.Comment: To appear at STOC 201

How Rotation Affects Masses and Ages of Classical Cepheids

Classical Cepheid variable stars are both sensitive astrophysical laboratories and accurate cosmic distance tracers. We have recently investigated how the evolutionary effects of rotation impact the properties of these important stars and here provide an accessible overview of some key elements as well as two important consequences. Firstly, rotation resolves the long-standing Cepheid mass discrepancy problem. Second, rotation increases main sequence lifetimes, i.e, Cepheids are approximately twice as old as previously thought. Finally, we highlight the importance of the short-period ends of Cepheid period distributions as indicators for model adequacy.Comment: 5 pages, 4 figures, proceedings of the 22nd Los Alamos Stellar Pulsation Conference "Wide-field variability surveys: a 21st-century perspective" held in San Pedro de Atacama, Chile, Nov. 28 - Dec. 2, 201

Investigation on Pesticide “Cocktail” Mixture usage among Rice Farmers in the Kadjebi District of Ghana

Pesticide “cocktail” mixtures are described as global phenomenon especially among farmers despite potential disadvantages. This study aimed to investigate the presence of the practice among rice farmers in the Kadjebi district in the Volta region of Ghana. The study involved a descriptive survey of rice farmers in the district using structured questionnaires. A total of 200 farmers from 8 communities were interviewed, out of which 195 questionnaires were found good enough for analyses.  Data from the study was analysed using SPSS version 16 and the results expressed in simple descriptive statistics including frequency counts, percentages etc. It was realised that herbicides were the only pesticides used by the farmers on their fields and it was mainly for land preparation and weed control among plants. As much as 13 brands of herbicides were used among the farmers. It was also realised that mixing pesticides into pesticide “cocktail” mixtures was common among the farmers with about three-quarters of the farmers (73.8%) involved participating in the act. It is recommended that the potential health and environmental effects of the practices of the farmers be assessed. KEY WORDS: Pesticides, herbicides, pesticides “cocktail” mixture, rice farmers

Reversible work extraction in a hybrid opto-mechanical system

With the progress of nano-technology, thermodynamics also has to be scaled down, calling for specific protocols to extract and measure work. Usually, such protocols involve the action of an external, classical field (the battery) of infinite energy, that controls the energy levels of a small quantum system (the calorific fluid). Here we suggest a realistic device to reversibly extract work in a battery of finite energy : a hybrid optomechanical system. Such devices consist in an optically active two-level quantum system interacting strongly with a nano-mechanical oscillator that provides and stores mechanical work, playing the role of the battery. We identify protocols where the battery exchanges large, measurable amounts of work with the quantum emitter without getting entangled with it. When the quantum emitter is coupled to a thermal bath, we show that thermodynamic reversibility is attainable with state-of-the-art devices, paving the road towards the realization of a full cycle of information-to-energy conversion at the single bit level.Comment: 10 pages, 3 figure

LINE POSITIONS FOR THE ν2 AND ν4 BANDS OF THE 5 ISOTOPOLOGUES OF GERMANE

\begin{wrapfigure}{r}{0pt} \includegraphics[scale=0.24]{GeH4_exp_sim.eps} \end{wrapfigure} Germane (GeH$_4$) is present in the atmospheres of the giant planets Jupiter and Saturn. Our recent analysis presented the complete modeling of line positions and intensities in the $\nu_1/\nu_3$ stretching dyad region near 2100~cm$^{-1}$\footnote{V. Boudon {\em et al.\/}, {\em J. Quant. Spectrosc. Radiat. Transfer} {\bf 205}, 174--183 (2018)}, of great interest for planetary applications. Nevertheless, this region contains a lot of hot bands. This situation leads to a very dense spectrum making deeper analyses difficult. In this study we present the first analysis and modeling of line positions in the $\nu_2/\nu_4$ bending dyad region for the five isotopologues. This analysis was conducted thanks to the formalism and programs developed in Dijon and allows to determine energy levels that are well suited for the hot band analyses, and therefore is a great improvement in the development of an accurate modeling needed for radiative transfer calculation for giant planets. These data will be integrated in our spectroscopic database (GeCaSDa\footnote{{http://vamdc.icb.cnrs.fr/PHP/gecasda.php}}) of calculated positions and intensities as soon as absolute intensities will be extracted from the spectra

SPECTROSCOPIC DATABASES FOR THE VAMDC PORTAL: NEW TOOLS AND IMPROVEMENTS

\begin{wrapfigure}{r}{0pt} \includegraphics[scale=0.5]{JPL-HITRAN-H2CO.eps} \end{wrapfigure} Dijon spectroscopic databases include calculated line lists, in positions and intensities, that are obtained from experimental spectroscopic analyses. They contain 6 molecules: CH$_4$, C$_2$H$_4$, CF$_4$, SF$_6$, GeH$_4$ and RuO$_4$ and are all compatibles with the XSAMS (XML Schema for Atoms, Molecules, and Solids) format adopted with the Virtual Atomic and Molecular Data Centre (VAMDC) Project. VAMDC, the worldwide consortium which federates atomic and molecular databases through an e-science infrastructure, aims to provide a unique access point for scientists seeking the best atomic and molecular data for their studies. So far, development of new tools allows to easily download and compare data issued from different databases in a single XML document or into the HITRAN2004 format. Making the comparison that easy will help data users in the choice of data that best match their needs. It will also help data producers by checking the consistency of their data

HIGH-RESOLUTION FAR INFRARED SPECTROSCOPY AND ANALYSES OF TRIOXANE

\begin{wrapfigure}{r}{0pt} \includegraphics[scale=0.2]{Trioxane.eps} \end{wrapfigure} Trioxane, (H$_2$CO)$_3$, is a symmetric top that belongs to the $C_{3v}$ symmetry group. The molecule owns 20 fundamental modes that are dispatched as 7 symmetric vibrations of type A1, 3 vibrations of type A2 and 10 doubly degenerate vibrations of type $E$. Infrared spectra of trioxane have been recorded in the 50--650 cm$^{-1}$ range using a high resolution Bruker IFS 125 interferometer located at the AILES beamline of the SOLEIL synchrotron facility. Owing to its higher brilliance in the far-infrared region, the SOLEIL synchrotron radiation was used to improve the signal-to-noise ratio of the spectrum at the maximal resolution of 0.001 cm$^{-1}$. We present here a detailed analysis and modeling of intense OCO deformation $\nu_7$ and $\nu_{19}$ modes as well as weaker CH$_2$ torsion $\nu_{20}$ mode and its first overtone 2$\nu_{20}$. Thanks to the formalism and programs developed in Dijon, we could determine accurately the effective Hamiltonian parameters for these 3 modes

FIRST ANALYSIS OF DOUBLY DEUTERATED DIMETHYL ETHER

\begin{wrapfigure}{r}{0pt} \includegraphics[scale=0.2]{DME2d.eps} \end{wrapfigure} Dimethyl ether is one of the most abundant molecule in star-forming regions. Like other complex organic molecules, its formation process is not yet clearly established. The study of deuteration may provide crucial hints. The mono-deuterated species (CH$_2$DOCH$_3$) was studied in 2012. This analysis led to a detection in ISM and results have been published by Richard et \emph{al}.\footnote{C. Richard et al., A\&A, 552, A117, 2013}. The spectra of the doubly deuterated species were recorded in Lille from 150 to 1500 GHz. We used the ERHAM code to treat the torsion of the methyl-group. So far, the analysis of both conformer symmetric and asymmetric are still in progress and we will present the first spectroscopic results, and their ISM search as well. This project has received financial support from the CNRS through the MITI interdisciplinary programs

Resources Description, Selection, Reservation and Verification on a Large-scale Testbed

International audienceThe management of resources on testbeds, including their description, reservation and verification, is a challenging issue, especially on of large scale testbeds such as those used for research on High Performance Computing or Clouds. In this paper, we present the solution designed for the Grid'5000 testbed in order to: (1) provide users with an in-depth and machine-parsable description of the testbed's resources; (2) enable multi-criteria selection and reservation of resources using a HPC resource manager; (3) ensure that the description of the resources remains accurate

Wolverine density distribution reflects past persecution and current management in Scandinavia

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