The effect of coherence and multiple scattering on laser radar air pollution measurements

Effect of coherence and multiple scattering on laser radar air pollution measurement

Public Attitudes and Systems-Analysis: Need for a Communications Framework

It is well known that urban and environmental problems are too complex to be amenable to complete quantitative solution. Most systems analysts have responded by constructing simulations that operate at a level of aggregation which allows for the use of some form of quantitative methodology. In doing so we have lost the ability to incorporate disaggregated and qualitative public attitudes in the overall system's analysis. Yet, public attitudes play a major role in the structure and function of urban and environmental systems and must be communicated to the analyst to avoid their being left outside the system boundary. It is the purpose of this paper to describe the major specifications of a communications framework between the public or its representatives and the systems analyst. The public sector decision making process has several areas in need of improved communications. One of these -- the feedback communication between the analyst and the public -- is being addressed here

Inventaires systématiques et sémantiques du patrimoine et des musées: [interfaces hommes-machines agiles]

Le but de ce projet est de donner une vue homogène d’un système d’informations muséal hétérogène. Ce qui permettra d’une part de faire des requêtes sur un ensemble de musées sans se préoccuper des aspects techniques sous-jacents et d’autre part de consolider les données réparties dans des sources n’ayant pas, a priori, de relations explicites. Cette homogénéité doit être mise en place par une architecture particulière impactant : la technologie il faut pouvoir interroger des bases de données de diverses technologies ; les modèles des bases de données il faut pouvoir interroger plusieurs bases de données simultanément même si leurs structures de données ne sont pas identiques ; le métier il faut intégrer la façon dont la base a été pensée à son origine et son objectif local. Ce mémoire fait partie d’un projet articulé en quatre volets et dont certaines parties ont été réalisées par plusieurs étudiants de la HEG. Les quatre volets de ce projet sont : les interfaces hommes-machines agiles, les connecteurs, la communication par agent et l’ontologie commune. Mon travail concerne la partie « interfaces hommes-machines agiles ». Cela implique l’utilisation de technologies web qui se chargera d’interpréter les résultats issus d’une recherche et de les présenter dynamiquement sur une page web. Ce mémoire est constitué de cinq parties et d’une conclusion. La première partie présente l’état de l’art des systèmes de classification des collections des musées et particulièrement de Genève (API) et Lausanne (Muséris). La seconde partie décrit le mandat qui m’a été confié. La troisième partie analyse le domaine et les démarches que j’ai mis en oeuvre. La quatrième partie s’étend sur les technologies utilisées dans le cadre du mandat. La cinquième partie détaille la réalisation du mandat et les étapes réalisées. La conclusion du mémoire présente une synthèse de l’ensemble du projet et une discussion sur mon expérience

Compositional variations of sea-salt-mode aerosol particles from the North Atlantic

Individual sea-salt-mode aerosol particles collected during the Atlantic Stratocumulus Transition Experiment/Marine Aerosol and Gas Exchange (ASTEX/MAGE) experiment in June 1992 were studied using transmission electron microscopy in both imaging and analysis modes. The set of eight samples provided an opportunity to compare ''clean,'' ''intermediate,'' and ''dirty'' oceanic aerosols. In the clean samples, major species include NaCl, mixed-cation (Na, Mg, K, and Ca) sulfates, and in some particles, NaNO3. The same compounds also occur in intermediate samples, but compositional groups can be distinguished that are characterized by low- and high-Cl losses from sea salt. In these samples, most Cl loss is compensated by NaNO3 formation. Several compositional groups occur in the dirty samples; these include, in addition to the particle types in clean and intermediate samples, Na2SO4 (with minor Mg, K, and Ca), (NH4)(2)SO4, and silicates. The uniform compositions of sea-salt-mode particles in the clean samples suggest that the same process was acting on all particles. Their excess sulfate and nitrate probably formed through the oxidation of SO2 in the sea-salt aerosol water and by reactions between NOx and NaCl. On the other hand, distinct compositional groups in the dirty samples reveal that long-range transport of continental air masses resulted in the mixing of aerosols that were exposed to different conditions. In addition to O-3 oxidation, cloud processing may have contributed to the formation of excess sulfate in these samples

Soot and sulfate aerosol particles in the remote marine troposphere

Sulfate aerosol particles containing soot aggregates were observed in the marine troposphere in both hemispheres under conditions that ranged from extremely clean to heavily polluted. Even in clean air above the remote Southern Ocean during the First Aerosol Characterization Experiment (ACE 1), depending on the sample, between 10 and 45% of sulfate particles contained soot inclusions. We identified aircraft emissions and biomass burning as the most likely major sources of soot. Internally mixed soot and sulfate appear to comprise a globally significant fraction of aerosols in the troposphere. Anthropogenic combustion aerosols can thus potentially change the radiative climate effects of sulfate aerosols and may have an impact on cloud properties even in the remote troposphere

Economic effects of the digital divide on pensioners in Germany regarding retail banking services

In the recent two decades, many service sector companies like banks altered their services and fees towards a regime whereby customers either bank online on their own or face comparatively high fees. The current phase of interest rates close to zero or even below - due to the euro crisis - enhances this trend. Many commercial banks in Germany have increased their fees for current accounts significantly, the common "free current account" policy has come more or less to an end. Many of the pensioners - in Germany there are more than 20 million retirees - are affected, because their pensions are quite low and they are not familiar with doing their banking the online way. This paper analyzes the situation based upon statistical data and develops other fee structures which are more just, from a social point of view, than burdening the elderly with low incomes

Environmental impact of shopping via the internet

Shopping via the internet is booming. High growth figures can still be expected in the future. More and more customers buy their goods online; the goods are then delivered to their home. Online customers especially love convenience. On the Internet, the large assortment is at a glance, the selection is independent of time and place, furthermore many products are cheaper. In this way, the customer can save money, save time and avoid ways to the city center. But is online shopping also climate-friendly? Climate-conscious behavior is an aspect that is currently being discussed a lot. The rapidly growing e-commerce is publicly criticized in many places for not being sustainable. Reference is made in particular to increase packaging waste, high return rates (and presumably destruction of returned goods) as well as longer distances that have to be covered for items in e-commerce on the way to the customer. Studies come to very different assessments of the environmental impact of ecommerce compared to traditional retail. This paper focuses on traffic-related environmental impacts when evaluating e-commerce

Insufficient Conditions for Distance Learning in Germany Exacerbate Educational Inequity

Every three years, the OECD conducts the so-called PISA studies (Programme for International Student Assessment), the largest international studies of school performance. These studies test whether participating pupils can apply their acquired knowledge and link information in a meaningful way - key competencies for being successful in the information society of the 21st century. Some 600,000 pupils from 79 countries and regions participated in the latest 2018 PISA test. In the first test, conducted in 2000, Germany's pupils performed poorly, but now they achieve above-average results. But of concern to german education policymakers is the substantial achievement gap between pupils from favorable socioeconomic backgrounds and those from unfavorable social backgrounds in Germany. Although there has been progress since the first study in 2000, there have been setbacks in recent years. Further setbacks could follow. Due to the Corona crisis, schools had to be closed for several weeks. At short notice and without preparation distance learning was prescribed. However, Germany is not sufficiently prepared for this. In an international comparison, the technical equipment in schools, a prerequisite for sustainable "digital" learning success for pupils, is not particularly good. Pupils' conditions at home, especially among disadvantaged pupils, are also often not conducive to successful distance learning. They are less well equipped with PCs and laptops, have less access to the Internet, receive significantly less support from their parents, and their housing conditions are much more cramped. This raises fears that social selectivity could increase

Crystalline silicate dust around evolved stars I. The sample stars

This is the first paper in a series of three where we present the first comprehensive inventory of solid state emission bands observed in a sample of 17 oxygen-rich circumstellar dust shells surrounding evolved stars. The data were taken with the Short and Long Wavelength Spectrographs on board of the Infrared Space Observatory (ISO) and cover the 2.4 to 195 micron wavelength range. The spectra show the presence of broad 10 and 18 micron bands that can be attributed to amorphous silicates. In addition, at least 49 narrow bands are found whose position and width indicate they can be attributed to crystalline silicates. Almost all of these bands were not known before ISO. We have measured the peak positions, widths and strengths of the individual, continuum subtracted bands. Based on these measurements, we were able to order the spectra in sequence of decreasing crystalline silicate band strength. We found that the strength of the emission bands correlates with the geometry of the circumstellar shell, as derived from direct imaging or inferred from the shape of the spectral energy distribution. This naturally divides the sample into objects that show a disk-like geometry (strong crystalline silicate bands), and objects whose dust shell is characteristic of an outflow (weak crystalline silicate bands). All stars with the 33.6 micron forsterite band stronger than 20 percent over continuum are disk sources. We define spectral regions (called complexes) where a concentration of emission bands is evident, at 10, 18, 23, 28, 33, 40 and 60 micron. We derive average shapes for these complexes and compare these to the individual band shapes of the programme stars.Comment: 41 pages, 20 figures, accepted by A&A. Tables 4 to 20 are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A