Shot noise and photon-induced correlations in 500 GHz SIS detectors

Photon-induced current correlations in SIS detectors can result in an output noise that is greater or less than shot noise. Evidence of these correlations had been observed for 100 GHz rf by accurate noise measurements as reported in our previous work. We now present a detailed analysis of these current correlations for frequencies between 100 and 500 GHz. We also report new measurements of photon-induced noise in a 490 GHz SIS mixer, and discuss the Gaussian beam techniques used to eliminate the thermal background radiation. For small 490 GHz rf power, the output noise is equal to shot noise. The results of the 100 and 490 GHz photon noise measurement are summarized in context to shot noise and the effect of the current correlations predicted by the theoretical model

A multi-wavelength study of the unidentified TeV gamma-ray source HESS J1626-490

HESS J1626-490, so far only detected with the H.E.S.S. array of imaging atmospheric Cherenkov telescopes, could not be unambiguously identified with any source seen at lower energies. Therefore, we analyzed data from an archival XMM-Newton observation, pointed towards HESS J1626-490, to classify detected X-ray point-sources according to their spectral properties and their near-infrared counterparts from the 2MASS catalog. Furthermore, we characterized in detail the diffuse X-ray emission from a region compatible with the extended VHE signal. To characterize the Interstellar Medium surrounding HESS J1626-490 we analyzed $^{12}$CO(J=1-0) molecular line data from the NANTEN Galactic plane survey, HI data from the Southern Galactic Plane Survey and Spitzer data from the GLIMPSE and MIPSGAL surveys. None of the detected X-ray point sources fulfills the energetic requirements to be considered as the synchrotron radiation (SR) counterpart to the VHE source assuming an Inverse Compton (IC) emission scenario. We did not detect any diffuse X-ray excess emission originating from the region around HESS J1626-490 above the Galactic Background and the derived upper limit for the total X-ray flux disfavors a purely leptonic emission scenario for HESS J1626-490. We found a good morphological match between molecular and atomic gas in the -27km/s to -18km/s line-of-sight velocity range and HESS J1626-490. The cloud has a mass of 1.8$times 10^4$M$_{odot}$ and is located at a mean kinematic distance of $d$ = 1.8 kpc. Furthermore, we found a density depression in the HI gas at a similar distance which is spatially consistent with the SNR G335.2+00.1. We discuss various scenarios for the VHE emission, including the CO molecular cloud being a passive target for cosmic ray protons accelerated by the nearby SNR G335.2+00.1.Comment: 9 pages, 10 figures, A&A in press, updated to the final versio

Chandra HRC Localization of the Low Mass X-ray Binaries X1624-490 and X1702-429: The Infrared Counterparts

We report on the precise localization of the low mass X-ray binaries X1624-490 and X1702-429 with the Chandra HRC-I. We determine the best positions to be 16:28:02.825 -49:11:54.61 (J2000) and 17:06:15.314 -43:02:08.69 (J2000) for X1624-490 and X1702-429, respectively, with the nominal Chandra positional uncertainty of 0.6". We also obtained deep IR observations of the fields of these sources in an effort to identify the IR counterparts. A single, faint (Ks=18.3 +/- 0.1) source is visible inside the Chandra error circle of X1624-490, and we propose this source as its IR counterpart. For X1702-429, a Ks=16.5 +/- 0.07 source is visible at the edge of the Chandra error circle. The brightness of both counterpart candidates is comparable to that of other low mass X-ray binary IR counterparts when corrected for extinction and distance.Comment: 5 pages, 2 figures, accepted for publication in Ap

A rotating disk around the very young massive star AFGL 490

We observed the embedded, young 8--10 Msun star AFGL 490 at subarcsecond resolution with the Plateau de Bure Interferometer in the C17O (2--1) transition and found convincing evidence that AFGL 490 is surrounded by a rotating disk. Using two-dimensional modeling of the physical and chemical disk structure coupled to line radiative transfer, we constrain its basic parameters. We obtain a relatively high disk mass of 1 Msun and a radius of ~ 1500 AU. A plausible explanation for the apparent asymmetry of the disk morphology is given.Comment: 4 pages, 5 figure

Visual Rhetoric in Outdoor Advertising

The paper presents a research, the aim of which is to find out how graphic expressions and visual language can be used for persuasion. The research material consists of outdoor advertisements photographed in their actual exhibition places in a city environment. Outdoor advertising media, which are used to communicate visual messages from a sender to several addressees, participate in building the visual city culture and open manifold solutions in design. The visual language used in the research material is analyzed in order to find out how advertising messages, their denotations and connotations, are constructed and how arguments used for persuasion are visualized. The first analysis is based on the knowledge and methods used in graphic design practice, which has been defined to be the process of making, choosing and arranging marks in order to convey a message. The analysis shows that different modes, techniques and visual elements are applied to attract the attention of spectators and arouse interest towards the message of an artefact. The second analysis is based on communication studies and semiotics, especially on Roman Jakobson’s theory about the functions of communication. The method of combining two analyses reveals different ways of using visual language and syntaxes to announce the excellence of an advertised product, service or subject. It also shows various types of visual arguments used in advertisements. Three types of visual rhetoric emerge from the research material. They are called brand rhetoric, personalized rhetoric and poetic rhetoric. The taxonomy of visual rhetoric exemplifies how visual language can be constructed and used for persuasion. It shows that the decisions in design influence the messages and meanings created. The research calls for further studies as regards the reception of visual rhetoric and suggests that the taxonomy of visual rhetoric could be applied in visual communication design and in the analysis of advertising messages. Keywords: Outdoor Advertisement/Advertising; Visual Rhetoric; Visual Language; Graphic Design; Visual Communication Design; Advertising Message</p

Information strategy development in the UK and Ireland: a role for Aleph

This paper looks at the role of the Ex Libris Strategy Group of UK and Irish Chief Librarians. It then analyses the role of Information provision at a strategic level in Universities in the UK. The paper identifies a Top Ten Wish List for development and partnership working with Ex Libris, comprising: Back to Basics, the Corporate Context, E-Journals, E-Books, Open Access, OAI compliance, the Catalogue, Management Information, Virtual and Managed Learning Environments, and international developments in information provision. The paper concludes that libraries must: support the institutional Mission, be seen to deliver, support their customers, and be cost-effective. Ex Libris software and products have an important role to play in delivering this agenda

Dielectric measurement based microstrip transmission line

The measurement of complex dielectric properties of materials at radio frequency is very important especially in the research fields, such as material science, microwave circuit design, absorber development, biological research, etc. Dielectric measurement is important because it can provide the electrical and magnetic characteristics of the materials, which proved useful in many research and development fields.The proposed technique present a simple microstrip transmission line method for the broadband radio frequency characterization of dielectric constant of non-dispersive materials. A microstrip line having impedance other than 50 Ω is designed and material under test is used as the substrate. The impedance mismatch between a non-50 Ω characteristic impedance of the microstrip line and 50 Ω coaxial to microstrip connectors generates significant reflection/transmission at the input ports. The mismatch between the input impedance and port is used to extract the dielectric constant of the substrate. For experimental validation, the microstrip trace is sticked on the test substrate which are FR4, Teflon and Roger 5880. During the measurement, the microstrip line is connected to vector network analyser through SMA connectors. It is found that this technique introduce error of 10.83%, 7.53% and 21.32% for FR4, Teflon and Roger 5880 respectively. On the other hand, the comparison with the experimental measurement shows 13.5%, 52.95% and 31.40% of error for FR4, Teflon and Roger 5880 respectively. The future research, can focus on measuring the dielectric properties of dispersive material including its loss factor material based on Kramers-kronig relationship

Redressing disadvantage and ensuring social cohesion: the role of distance education and elearning policies in the European Union 1957-2007

This paper analyses the development and implementation of the European Union's policies in distance higher education and elearning since the 1957 Treaty of Rome. Distance education emerged in the 1960s and 70s as an instrument at national level to redress disadvantage, and to provide flexible, high-quality and cost-effective access to higher education to adults who were unable, for geographical, employment or personal reasons, to attend on-campus. Analysis of EU policy documents and interviews with key individuals indicates that the support of influential policy entrepreneurs and networks brought distance education to the centre stage in EU education and training policy for a brief period in the early 1990s, culminating in the Maastricht Treaty on European Union (1992), which committed the EU to ‘encouraging the development of distance education’. Since then, distance learning has been superceded by elearning, and is linked in EU rhetoric to social cohesion in the context of making Europe the most competitive economy in the world. Yet, despite the great potential of elearning, this paper outlines the challenges to its wider adoption. These include the persistence of the digital divide in Europe; student resistance to elearning approaches; and the problem of achieving cost-effectiveness in elearning. Much remains to be done to ensure the flexibility in terms of time, place, pace, and indeed accessibility, which would enable adult students to participate in lifelong learning on a truly democratic basis

East Midlands Transport Equipment Sector Strategy

Transport equipment has been identified as a key sector in the East Midlands economy. This strategy sets out a vision for the development of the sector and how it can contribute to the attainment of regional economic development objectives