Electronic transport through a quantum dot network

The conductance through a finite quantum dot network is studied as a function of inter-dot coupling. As the coupling is reduced, the system undergoes a transition from the antidot regime to the tight binding limit, where Coulomb resonances with on average increasing charging energies are observed. Percolation models are used to describe the conduction in the open and closed regime and contributions from different blockaded regions can be identified. A strong negative average magnetoresistance in the Coulomb blockade regime is in good quantitative agreement with theoretical predictions for magnetotunneling between individual quantum dots.Comment: 5 pages, 5 figure

Etude et modélisation des potentiels du SAR basse fréquence pour l'exploration de la sub-surface en contexte aride

La télédétection radar a connu un grand développement ces dernières années, majoritairement pour l'observation de la Terre, mais également pour l'exploration planétaire. Alors que l'essentiel des applications à ce jour concerne l'étude des surfaces, le SAR permet, sous certaines conditions d'aridité, de scruter les sous-sols et c'est cette capacité que nous avons étudié plus en détail. L'objectif de notre travail était de valider, de façon expérimentale et théorique, un ensemble de techniques et de méthodes permettant d'étudier et de caractériser le sous-sol à distance. A partir de l'étude de deux sites tests (le Pyla, France et la région de Bir Safsaf, Egypte), nos travaux ont permis de mettre en évidence des structures enfouies (interface géologique, humidité du sous-sol) par des signatures caractéristiques et d'évaluer les performances de tels systèmes, laissant entrevoir des champs d'applications nouveaux et très vastes : ressource en eau, cartographie géologique, archéologie, etc.Up to now, radar remote-sensing have been mostly used for Earth-Observation. It is now used in investigation projects on solar system bodies as well. Most of applications usually concern surfaces but, in arid conditions, the SAR can help souding and analyzing the subsurface, and we particularly focused on this ability. Using experimental and theoritical approaches, the aim of our work was to validate a set of techniques and methods in order to quantitatively study and characterize the subsurface structures. From studies performed on two test-sites (the Pyla Dune in France and the Bir Safsaf region in Egypt), we put in evidence the presence of embedded structures (geological interface, moisture) and determined their characteristics. We also estimated the penetrating performances of such systems and studied a typical signature of the subsurface moisture. Our results are of interest for a wide range of applications like water resources prospection, geological mapping, archeology, etc

Unproceedings of the Fourth .Astronomy Conference (.Astronomy 4), Heidelberg, Germany, July 9-11 2012

The goal of the .Astronomy conference series is to bring together astronomers, educators, developers and others interested in using the Internet as a medium for astronomy. Attendance at the event is limited to approximately 50 participants, and days are split into mornings of scheduled talks, followed by 'unconference' afternoons, where sessions are defined by participants during the course of the event. Participants in unconference sessions are discouraged from formal presentations, with discussion, workshop-style formats or informal practical tutorials encouraged. The conference also designates one day as a 'hack day', in which attendees collaborate in groups on day-long projects for presentation the following morning. These hacks are often a way of concentrating effort, learning new skills, and exploring ideas in a practical fashion. The emphasis on informal, focused interaction makes recording proceedings more difficult than for a normal meeting. While the first .Astronomy conference is preserved formally in a book, more recent iterations are not documented. We therefore, in the spirit of .Astronomy, report 'unproceedings' from .Astronomy 4, which was held in Heidelberg in July 2012.Comment: 11 pages, 1 figure, .Astronomy 4, #dotastr

Tuning the Nigerian Slit Gong

An experimental and theoretical investigation of the Nigerian slit gong is reported. It is shown that in tuning the gong the artisan ensures that the frequencies of the two lowest mechanical resonances are nearly coincident with the frequencies of two of the acoustic resonances of the internal cavity. Four possible tuning parameters are identified and the effects of changing these parameters is discussed

Study of some factors affecting efficiency of reproduction in dairy cattle serviced by artificial insemination

This bulletin is a report on Department of Dairy Husbandry research project number 89 entitled 'Increasing the effectiveness of artificial insemination as a means of improving dairy cattle'--P. [2].Includes bibliographical references (pages 40-42)

West Nile premembrane-envelope genetic vaccine encoded as a chimera containing the transmembrane and cytoplasmic domains of a lysosome-associated membrane protein: increased cellular concentration of the transgene product, targeting to the MHC II compartment, and enhanced neutralizing antibody response

AbstractA genetic vaccine for West Nile virus (WN) has been synthesized with the WN premembrane-envelope (WN preM-E) gene sequences encoded as a chimera with the transmembrane and carboxyl terminal domains of the lysosome-associated membrane protein (LAMP). The LAMP sequences are used to direct the antigen protein to the major histocompatibility class II (MHC II) vesicular compartment of transfected professional antigen-presenting cells (APCs). Vaccine constructs encoding the native WN preM-E and WN preM-E/LAMP chimera were synthesized in pVAX1 and pITR plasmid backbones. Extracts of human fibroblast 293 and monkey kidney COS-7 cells transfected with the WN preM-E/LAMP chimera constructs contained much greater amounts of E than did the cells transfected with constructs encoding the native WN preM-E. This difference in the concentration of native E and the E/LAMP chimera in transfected cells is attributed to the secretion of native E. The amount of preM protein in cell extracts, in contrast to the E protein, and the levels of DNA and RNA transcripts, did not differ between WN preM-E- and WN preM-E/LAMP-transfected cells. Additionally, confocal and immunoelectron microscopic analyses of transfected B cells showed localization of the WN preM-E/LAMP chimera in vesicular compartments containing endogenous LAMP, MHC II, and H2-M, whereas native viral preM-E lacking the LAMP sequences was distributed within the cellular vesicular network with little LAMP or MHC II association. Mice immunized with a DNA construct expressing the WN preM-E/LAMP antigen induced significant antibody and long-term neutralization titers in contrast to the minimal and short-lived neutralization titer of mice vaccinated with a plasmid expressing the untargeted antigen. These results underscore the utility of LAMP targeting of the WN envelope to the MHC II compartments in the design of a genetic WN vaccine