List Distinguishing Parameters of Trees

A coloring of the vertices of a graph G is said to be distinguishing} provided no nontrivial automorphism of G preserves all of the vertex colors. The distinguishing number of G, D(G), is the minimum number of colors in a distinguishing coloring of G. The distinguishing chromatic number of G, chi_D(G), is the minimum number of colors in a distinguishing coloring of G that is also a proper coloring. Recently the notion of a distinguishing coloring was extended to that of a list distinguishing coloring. Given an assignment L= {L(v) : v in V(G)} of lists of available colors to the vertices of G, we say that G is (properly) L-distinguishable if there is a (proper) distinguishing coloring f of G such that f(v) is in L(v) for all v. The list distinguishing number of G, D_l(G), is the minimum integer k such that G is L-distinguishable for any list assignment L with |L(v)| = k for all v. Similarly, the list distinguishing chromatic number of G, denoted chi_{D_l}(G) is the minimum integer k such that G is properly L-distinguishable for any list assignment L with |L(v)| = k for all v. In this paper, we study these distinguishing parameters for trees, and in particular extend an enumerative technique of Cheng to show that for any tree T, D_l(T) = D(T), chi_D(T)=chi_{D_l}(T), and chi_D(T) <= D(T) + 1.Comment: 10 page

Charge Transfer Emission in Oligotriarylamine-Triarylborane Compounds

Donor–acceptor compounds exhibiting charge transfer emission are of interest in a variety of different contexts, for example, for nonlinear optical processes and for sensor applications. Recently investigated triarylamine–triarylborane compounds represent an important class of donor–acceptor systems, and we explored to what extent their charge-transfer properties can be further improved by using stronger amine donors and borane acceptors than prior studies. The oligotriarylamine employed here is a much stronger donor than previously used triarylamines containing single nitrogen centers. In order to increase the acceptor strength, the electron-accepting unit was equipped with two (instead of one) dimesitylboron substituents. In our comparative study, six donor–acceptor compounds were synthesized and investigated by cyclic voltammetry and optical spectroscopy. An increase of the donor strength through replacement of an ordinary triarylamine by an oligotriarylamine unit leads to the expected energetic stabilization of charge transfer (CT) excited states, but the emission solvatochromism is not more pronounced. The attempted increase of the acceptor strength by substitution of the acceptor moiety by two (instead of one) dimesitylboron groups leads to a drastic decrease of emission quantum yields. On the basis of these results, our purely experimental study provides fundamental guidelines for the design of new triarylamine–triarylborane donor–acceptor compounds with favorable charge-transfer emission properties

Object Detection and 3D Estimation via an FMCW Radar Using A Fully Convolutional Network

This paper considers object detection and 3D estimation using an FMCW radar. The state-of-the-art deep learning framework is employed instead of using traditional signal processing. In preparing the radar training data, the ground truth of an object orientation in 3D space is provided by conducting image analysis, of which the images are obtained through a coupled camera to the radar device. To ensure successful training of a fully convolutional network (FCN), we propose a normalization method, which is found to be essential to be applied to the radar signal before feeding into the neural network. The system after proper training is able to first detect the presence of an object in an environment. If it does, the system then further produces an estimation of its 3D position. Experimental results show that the proposed system can be successfully trained and employed for detecting a car and further estimating its 3D position in a noisy environment.Comment: 5 page

The FEM Wiki Project: A Conversion of a Training Resource for Field Epidemiologists into a Collaborative Web 2.0 Portal

While an ever increasing popularity of online wiki platforms, user-tagging tools, blogs, and forums is the core characteristic of the Web 2.0 era, converting an existing high-quality training module into a collaborative online space for an active community of practice (CoP) while preserving its quality approval processes is a challenging task. This is the aim of the ECDC-funded Field Epidemiology Manual (FEM) wiki project, based on training resources organized in 17 chapters developed for the European EPIET epidemiology training programme. This paper describes the challenges, solutions, and development processes behind the FEM wiki portal – an online collaborative Web 2.0 platform taking advantage of the user-generated input while preserving the structure, editorial processes and style of the existing FEM manual. We describe the need for ECDC-recognised content and discuss the editorial roles developed in this European project but applicable to any other training resource converted into an online wiki platform

The ALADIN Interactive Sky Atlas

The Aladin interactive sky atlas, developed at CDS, is a service providing simultaneous access to digitized images of the sky, astronomical catalogues, and databases. The driving motivation is to facilitate direct, visual comparison of observational data at any wavelength with images of the optical sky, and with reference catalogues. The set of available sky images consists of the STScI Digitized Sky Surveys, completed with high resolution images of crowded regions scanned at the MAMA facility in Paris. A Java WWW interface to the system is available at: http://aladin.u-strasbg.fr/Comment: 8 pages, 3 Postscript figures; to be published in A&

Zinc Extraction potential of two common crop plants, Nicotiana tabacum and Zea mays

A field study was conducted to investigate the efficiency of Zn phytoextraction by Nicotiana tabacum and Zea mays from a soil that had been artificially contaminated by different amounts of ZnSO4 (0, 50, 150, 350, 750 and 1550 mg kg−1 soil) 10 years prior to the present cropping. Increased NaNO3-extractable Zn in soil translated well into shoot concentrations (dry matter) in plants. Zn uptake by Z. mays increased linearly with increasing NaNO3-extractable Zn in soil, while for N. tabacum the increase could be described by a Langmuir isotherm. While Z. mays showed no significant decrease in biomass production up to the highest contamination level in soil, N. tabacum responded with a reduction of plant growth of about 50% compared with control plants at the highest Zn concentrations in soil. Maximum removal of Zn was 13 kg ha−1 y−1 with Z. mays and 11 kg ha−1 y−1 with N. tabacum. Calculated time required to reduce soil Zn from 350 to 150 mg kg−1 was about 55 years for N. tabacum and about 63 years for Z. mays at a soil pH of 4.8. At higher soil pH of 6.0 calculated decontamination time was about 87 years for N. tabacum and more than 200 years for Z. mays. Only small amounts of Zn were translocated into the seeds of N. tabacum and cobs of Z. mays. Therefore, corn cobs of Z. mays could be safely used for fodder and the seeds of N. tabacum, which are rich in oil, for industrial purposes, e.g. in the paint industr

Pulsed squeezed vacuum characterization without homodyning

Direct photon detection is experimentally implemented to measure the squeezing and purity of a single-mode squeezed vacuum state without an interferometric homodyne detection. Following a recent theoretical proposal [arXiv quant-ph/0311119], the setup only requires a tunable beamsplitter and a single-photon detector to fully characterize the generated Gaussian states. The experimental implementation of this procedure is discussed and compared with other reference methods.Comment: 8 pages, 7 figure

Distributed leadership, trust and online communities

This paper analyses the role of distributed leadership and trust in online communities. The team-based informal ethos of online collaboration requires a different kind of leadership from that in formal positional hierarchies. Such leadership may be more flexible and sophisticated, capable of encompassing ambiguity and rapid change. Online leaders need to be partially invisible, delegating power and distributing tasks. Yet, simultaneously, online communities are facilitated by the high visibility and subtle control of expert leaders. This paradox: that leaders need to be both highly visible and invisible as appropriate, was derived from prior research and tested in the analysis of online community discussions using a pattern-matching process. It is argued that both leader visibility and invisibility are important for the facilitation of trusting collaboration via distributed leadership. Advanced leadership responses to complex situations in online communities foster positive group interaction and decision-making, facilitated through active distribution of specific tasks