Yes / Dust storms are one of the natural phenomena, which have increased in frequency in recent years in North Africa, Australia and northern China. Satellite remote sensing is the common method for monitoring dust storms but its use for identifying dust storms over sandy ground is still limited as the two share similar characteristics. In this study, an artificial neural network (ANN) is used to detect dust storm using 46 sets of data acquired between 2001 and 2010 over North Africa by the Moderate Resolution Imaging Spectroradiometer (MODIS) instruments aboard the Terra and Aqua satellites. The ANN uses image data generated from Brightness Temperature Difference (BTD) between bands 23 and 31 and BTD between bands 31 and 32 with three bands 1, 3, and 4, to classify individual pixels on the basis of their multiple-band values. In comparison with the manually detection of dust storms, the ANN approach gave better result than the Thermal Infrared Integrated Dust Index approach for dust storms detection over the Sahara. The trained ANN using data from the Sahara desert gave an accuracy of 0.88 when tested on data from the Gobi desert and managed to detect 90 out of the 96 dust storm events captured worldwide by Terra and Aqua satellites in 2011 that were classified as dusty images on NASA Earth Observatory. / IEEE Geoscience and Remote Sensing Society

Light pollution is a problem that affects both living creatures as well as the perception of the night sky. As artificial lighting becomes more affordable and energy efficient, more and more lights are being used, further increasing the light pollution produced by us humans where cities with larger populations experience the largest amount of light pollution. There is however a knowledge gap in the field of light pollution regarding the possibility of a relationship between sky view factor and the brightness of the night sky. This study attempts to reduce that knowledge gap. By using cameras to take photos in different locations, the brightness of the night sky can be compared and together with the sky view factor of each location in can be determined if there exist such a relationship. Based on the results of this study, trends suggesting that this relationship exists emerges, however not to the extent that any definite conclusions can be drawn without further studies.

Im Unterschied zu anderen RNA Viren vervielfältigen Influenzaviren ihr Genom im Zellkern infizierter Zellen. Für die erfolgreiche Vermehrung müssen neu gebildete Genomsegmente (virale Ribonukleoproteine, vRNPs) wieder aus dem Zellkern exportiert werden. Dafür nutzt Influenza einen Exportkomplex, der sich aus dem viralen Matrixprotein 1 (M1) und Nukleusexportprotein (NEP) zusammensetzt und vRNPs unter Verwendung des zellulären Exportproteins CRM1 aus dem Zellkern transportiert. Zahlreiche Fragen im Zusammenhang mit dem Exportkomplex sind noch unbeantwortet: Wie viele Exportkomplexe werden pro vRNP gebunden? Wie interagieren die Proteine innerhalb des Komplexes mit vRNPs? Wie wird die zeitliche und räumliche Präsenz der beteiligten Proteine im Verlauf der Infektion reguliert? Um zu einem besseren Verständnis beizutragen, wurden in der vorliegenden Arbeit Fluoreszenzfluktuationsspektroskopie und molecular brightness-Analysen genutzt, um die Oligomerisierung der beteiligten Exportkomplexproteine zu quantifizieren. Werden Fluoreszenzproteine für solche Untersuchungen verwendet, treten häufig nicht-fluoreszente Zustände auf, die die Bestimmung des Oligomerzustandes beeinflussen. Daher wurde in dieser Arbeit ein einfaches Korrekturmodel vorgestellt, das die Population an nicht-fluoreszenten Zuständen berücksichtigt, und somit die genaue Bestimmung des Oligomerzustandes erlaubt. Dadurch konnte zum ersten Mal gezeigt werden, dass NEP Homodimere im Zytoplasma ausbildet, wohingegen eine um das 2,5-fach geringere Homodimerpopulation im Zellkern vorhanden war. Durch die Integration von Informationen über den Lokalisationsphänotyp und den Oligomerzustand von NEP sowie mehrerer Mutanten, konnte ein Modell abgeleitet werden, dass den Regulationsmechanismus beschreibt: Durch vorrübergehendes Maskieren und Demaskieren der beiden Nukleusexportsignale wird der Transport von NEP reguliert. Die Dimerisierung im Zytoplasma und Monomerisierung im Zellkern unterstützen diesen Mechanismus. / Influenza viruses are the causative agent of severe epidemics and pandemics, causing up to 650,000 deaths annually. Unlike other RNA viruses, Influenza viruses replicate their genome within the nucleus of cells. Hence, progeny genome segments - viral ribonucleoproteins (vRNPs) - need to be exported from the nucleus to complete the replication cycle. To fulfil this task, Influenza relies on a viral nuclear export complex built from M1 and NEP, that mediates export by hijacking the cellular CRM1-dependent export machinery. In this context a number of questions remain unanswered, such as how many export complexes bind to a single vRNP, what is the exact interaction pattern of vRNPs with export complex proteins, and how translocation of nuclear export relevant proteins such as NEP are regulated and optimally timed during the course of infection? In the present study, the potential of NEP to form homo-dimers in situ was shown for the first time by applying fluorescence fluctuation spectroscopy (FFS) and molecular brightness analysis, that allows determination of protein oligomerization in living cells. However, when using fluorescent proteins in FFS studies non-fluorescent states are observed, which strongly affect molecular brightness analysis. Therefore, in this study a simple correction model was described, taking into account quantified non-fluorescent state fractions, to finally allow accurate and unbiased determination of oligomerization. This way it was shown, that NEP forms homo-dimers within the cytoplasm of cells, whereas a 2.5-fold lower homo-dimer population was observed in the nucleus. Combining the subcellular localization dependent oligomeric state of NEP and several NEP mutants with their localization phenotypes, a regulation mechanism was proposed in which the translocation of NEP is regulated by transient masking and unmasking of its two NESs, which is supported by dimerization in the cytoplasm and monomerization in the nucleus of cells, respectively.

No description available.

SIMS est une technique d'analyse sensible de la surface. La probabilité d'ionisation dépend de l'état chimique de la surface. La génération des ions positifs est améliorée par le bombardement de la surface avec des éléments électronégatifs.Sur le NanoSIMS 50 de CAMECA, dont la configuration optique nécessite une polarité opposée entre ions primaires et secondaires, l'analyse des ions positifs se fait sous bombardement d'ions O-, générés dans un duoplasmatron. La faible brillance de la source en mode O- a comme conséquence une faible résolution latérale des analyses. Pour y remédier, nous avons étudié la possibilité de générer d’autres faisceaux d’ions primaires négatifs. Dans cet objectif, nous avons étudié la génération par duoplasmatron d'ions F-, Cl-, Br- et I- en fonction du champ magnétique, du courant d'arc et de la pression totale des gaz. Le courant d'ions et le diamètre du faisceau ont été mesurés afin de déterminer la brillance de la source en mode F-, Cl-, Br- et I-. Une brillance 5 fois plus élevée en mode F- qu'en mode O- a été déterminée.En utilisant les faisceaux F-, Cl-, Br- et I-, le rendement de pulvérisation, la concentration d'ions primaires implantés et le rendement utile ont été mesurés pour des semi-conducteurs et des métaux. Suite à une faible concentration en halogène à la surface des semi-conducteurs, résultant des processus de décapage, le rendement utile sous bombardement halogène était plus faible que sous bombardement O-. Pour les métaux (p.ex. Ni, Cu et Ag) par contre, une amélioration du rendement utile sous bombardement halogène jusqu'à deux ordres de grandeurs, comparé au bombardement O-, a été mesurée / Secondary Ion Mass spectrometry (SIMS) is a powerful surface analysis technique. The ionisation probability strongly depends on the chemical surface state. The generation of positive secondary ions can be enhanced by surface bombardment with electronegative elements.Due to the optical configuration of the CAMECA NanoSIMS 50, that necessitates an opposite polarity of incoming and ejected ions, analyses of positive ions are realized with primary O- ions, generated in a duoplasmatron ion source. As a consequence of the low O- brightness of the duoplasmatron source, the lateral resolution of the analyses on the NanoSIMS 50 is not satisfactory in the positive secondary mode. In this work, we studied the feasibility of different alternative negative primary ion beams. We investigated the possibility of F-, Cl-, Br- and I- ion generation with a duoplasmatron as a function of the source parameters, notably the magnetic field strength, the arc current and the total gas pressure. The ion current and the beam diameter were measured in order to determine the F-, Cl-, Br- and I- brightness of the source. A comparative study with the O- brightness demonstrates an increase of the F- brightness by a factor of 5.By using the F-, Cl-, Br- and I- bombardment, the sputtering yield, the concentration of implanted primary ions and the useful yield of different semi-conductor and metal samples were analysed. As a consequence of a low halogen concentration, related to etching effects, no enhancement of the useful yield could be noticed for the semi-conductors. For metals however (e.g. Ni, Cu and Ag), useful yield enhancements by up to a factor of 100 compared to the O- bombardment could be demonstrated

Dust storms are one of the natural hazards, which have increased in frequency in the recent years over Sahara desert, Australia, the Arabian Desert, Turkmenistan and northern China, which have worsened during the last decade. Dust storms increase air pollution, impact on urban areas and farms as well as affecting ground and air traffic. They cause damage to human health, reduce the temperature, cause damage to communication facilities, reduce visibility which delays both road and air traffic and impact on both urban and rural areas. Thus, it is important to know the causation, movement and radiation effects of dust storms. The monitoring and forecasting of dust storms is increasing in order to help governments reduce the negative impact of these storms. Satellite remote sensing is the most common method but its use over sandy ground is still limited as the two share similar characteristics. However, satellite remote sensing using true-colour images or estimates of aerosol optical thickness (AOT) and algorithms such as the deep blue algorithm have limitations for identifying dust storms. Many researchers have studied the detection of dust storms during daytime in a number of different regions of the world including China, Australia, America, and North Africa using a variety of satellite data but fewer studies have focused on detecting dust storms at night. The key elements of this present study are to use data from the Moderate Resolution Imaging Spectroradiometers on the Terra and Aqua satellites to develop more effective automated method for detecting dust storms during both day and night and generate a MODIS dust storm database.

Image quality measures are used to optimize image processing algorithms and evaluate their performances. The only reliable way to assess image quality is subjective evaluation by human observers, where the mean value of their scores is used as the quality measure. This is known as mean opinion score (MOS). In addition to this measure there are various objective (quantitative) measures. Most widely used quantitative measures are: mean squared error (MSE), peak signal to noise ratio (PSNR) and signal to noise ratio (SNR). Since these simple measures do not always produce results that are in agreement with subjective evaluation, many other quality measures have been proposed. They are mostly various modifications of MSE, which try to take into account some properties of human visual system (HVS) such as nonlinear character of brightness perception, contrast sensitivity function (CSF) and texture masking. In these approaches quality measure is computed as MSE of input image intensities or frequency domain coefficients obtained after some transform (DFT, DCT etc.), weighted by some coefficients which account for the mentioned properties of HVS. These measures have some advantages over MSE, but their ability to predict image quality is still limited. A different approach is presented here. Quality measure proposed here uses simple model of HVS, which has one user-defined parameter, whose value depends on the reference image. This quality measure is based on the average value of locally computed correlation coefficients. This takes into account structural similarity between original and distorted images, which cannot be measured by MSE or any kind of weighted MSE. The proposed measure also differentiates between random and signal dependant distortion, because these two have different effect on human observer. This is achieved by computing the average correlation coefficient between reference image and error image. Performance of the proposed quality measure is illustrated by examples involving images with different types of degradation.

Ma thèse a pour objet l’étude des couleurs du mobilier d’apparat en bronze dans le monde gréco-romain, produit entre le IIe s. av. n. è. et le IIe s. de n. è. en Méditerranée. Elle place au cœur de sa démarche historique la caractérisation des couleurs, leur analyse technique et l’étude de leurs valeurs symboliques, associées à des contextes de production et de réception précis. Redonner en effet aux couleurs toute leur place dans l’ameublement de luxe en bronze, en conduire l’étude typologique, iconographique et technique, les replacer dans leur contexte de réception permet de comprendre non seulement l’impact visuel recherché par le maître de maison, mais aussi et surtout leurs valeurs spécifiques dans l’élaboration du discours des élites à destination de leurs semblables et des autres classes de la société. Pour identifier et comprendre cette polychromie, une démarche interdisciplinaire combinant des méthodologies archéologiques, archéométriques et sociologiques a été appliquée. 538 pièces de mobilier en bronze à décors polychromes sont ainsi recensées et réparties dans diverses catégories. Ces multiples données sont réunies et mises en relation grâce à la création et l’utilisation d’une base de données relationnelle nommée « Iris ». La convergence de ces méthodes et de ces angles d’attaque du matériel étudié vise à un seul but : apprécier la valeur des couleurs et des autres traitements de surface de ces objets de luxe d’inspiration grecque dans le processus général d’acculturation des populations et provinces romaines au modèle gréco-romain, un modèle défini par Paul Veyne comme propre à un Empire où « la culture y était hellénique et le pouvoir était romain ». / My thesis aims to study the colours of bronze ceremonial furniture produced by the Greco-Roman world between the 2nd century BCE and the 2nd century CE in the Mediterranean. The main objective is to characterize of colours, their technical properties, and symbolic values associated with specific production and reception contexts.Consequently, by using archaeological contexts, techno-typological and iconographic studies, the objective of this research is to characterize the specificity and originality of the use and visual impact of bronze in the elaboration of the discourse of the Greco-Roman elite, owner of this ostentatious furniture; this discourse is also aimed at this elite as other classes of Roman society.My thesis explores as much the history of techniques as that of arts and mentalities. It combines archaeological, archaeometric, and sociological methodologies for an interdisciplinary approach. 538 pieces of bronze furniture with polychrome decorations are identified and divided into different categories. Furthermore, these multiple data are also collected and linked through the creation and use of a relational database named “Iris”.The convergence of these methods has a single purpose: to appreciate the significance of colours and to investigate other surface treatments on Greek inspired luxury furnishings. The gradual acculturation of “the Greek world” as a result of Roman expansion is evident in a study of this furniture, its colours, and other treatments using the same historical perspective as defined by Paul Veyne as: an Empire where “la culture y était hellénique et le pouvoir était romain”.

<p><font face="Arial"> <p align="left">The aim of this study is to compare proximal caries depth on unenhanced storage phosphor plate images and conventional film images. The phosphor plate images were then copied by increasing and decreasing both contrast and brightness respectively. The enhanced phosphor plate images were compared with the unenhanced storage phosphor plate images and conventional film images for the detection of proximal caries diagnosis.</p> </font></p>

No description available.