Abstract
The GeoModel toolkit is an open-source suite of standalone tools that provides the user with lightweight tools to describe, visualize, test, and debug detector descriptions and geometries ...for HEP standalone studies and experiments. GeoModel has been designed with independence and responsiveness in mind and offers a development environment free of other large HEP tools and frameworks, and with a very quick development cycle. With very few and lightweight dependencies, GeoModel is easy to install on all systems, in a modular way; and pre-compiled binaries are provided for the major platforms, for a quick and easy installation. Coded entirely in C++, GeoModel offers the user tools to describe geometries inside C++ code or in external XML files, create persistent representation with a low disk footprint and interactively visualize and inspect the geometry in a 3D view. It also offers a plugin mechanism and an optional Geant4 application to simulate the described geometry in a standalone environment. GeoModel has been developed as part of the software for the ATLAS experiment at the LHC, and evolved towards an experiment-independent toolkit. In this contribution, we describe all the available tools, with a focus on the latest additions, which provide users with more visualization, debug, and simulation tools.
Size‐segregated marine aerosols were collected at Mace Head Atmospheric Research Station (Ireland) during spring and autumn 2002 corresponding with the phytoplankton bloom periods in the North ...Atlantic. Strict control of the sampling, air mass back trajectory analysis, and analysis of pollutant tracers allowed the selection of a set of samples representative of clean marine conditions. A comprehensive chemical characterization of both (1) water‐soluble and water‐insoluble organic fraction and (2) water‐soluble inorganic ions was performed. The selected samples illustrated a consistent picture in terms of chemical composition. The supermicron mode predominantly comprises sea‐salt aerosol with a mass concentration of 10.16 ± 0.80 μg m−3, the remainder being non‐sea‐salt (nss) sulphate, 0.03 ± 0.01 μg m−3, and nitrate, 0.13 ± 0.04 μg m−3. By comparison, the mass of sea salt, nss sulphate, and nitrate in the submicron mode is found to be 0.39 ± 0.08 μg m−3, 0.26 ± 0.04 μg m−3, and 0.02 ± 0.01 μg m−3, respectively. Water‐soluble organic carbon (WSOC) is observed in the submicron mode with a mass concentration of 0.25 ± 0.04 μg m−3, comparable to that of nss sulphate, and in the supermicron mode with a mass concentration of 0.17 ± 0.04 μg m−3. The WSOC to total carbon (TC) ratio is found to be 0.20 ± 0.12 for the submicron fraction and 0.29 ± 0.08 for the supermicron fraction, while the black carbon (BC) to TC ratio is, on average, 0.032 ± 0.001 for both aerosol modes. The remaining carbon, water‐insoluble organic carbon, contributes 0.66 ± 0.11 μg m−3 and 0.26 ± 0.06 μg m−3 to the submicron and supermicron modes, respectively and, thus, represents the dominant submicron aerosol species. Furthermore, the WSOC chemical composition comprises mainly aliphatic and only partially oxidized species and humic‐like substances, resulting in appreciable surface‐active properties. The observed organic matter chemical features (size‐dependent concentration, hydrophobic nature of a substantial fraction of the organic matter, and low oxidized and surface‐active WSOC species) are consistent with the hypothesis of a primary marine source; bubble‐bursting processes, occurring at the surface of the North Atlantic Ocean during phytoplankton blooms, effectively transfer organic matter into marine aerosol particles, particularly enriching the fine‐aerosol fraction.
Aerosol properties have been monitored by ground-based in situ and remote sensing measurements at the station for atmospheric research located in Ispra, on the edge of the Po Valley, for almost one ...decade. In situ measurements are performed according to Global Atmosphere Watch recommendations, and quality is assured through the participation in regular inter-laboratory comparisons. Sun-photometer data are produced by the Aerosol Robotic Network (AERONET). Data show significant decreasing trends over the 2004–2010 period for a number of variables, including particulate matter (PM) mass concentration, aerosol scattering, backscattering and absorption coefficients, and aerosol optical thickness (AOT). In situ measurement data show no significant trends in the aerosol backscatter ratio, but they do show a significant decreasing trend of about −0.7 ± 0.3% yr−1 in the aerosol single scattering albedo (SSA) in the visible light range. Similar trends are observed in the SSA retrieved from sun-photometer measurements. Correlations appear between in situ PM mass concentration and aerosol scattering coefficient, on the one hand, and elemental carbon (EC) concentration and aerosol absorption coefficient, on the other hand. However, no increase in the EC / PM ratio was observed, which could have explained the decrease in SSA. The application of a simple approximation to calculate the direct radiative forcing by aerosols suggests a significant diminution in their cooling effect, mainly due to the decrease in AOT. Applying the methodology we present to those sites, where the necessary suite of measurements is available, would provide important information to inform future policies for air-quality enhancement and fast climate change mitigation.
This study focuses on the aerosol hygroscopic properties as determined from ground-based measurements and Mie theory. Usually, aerosol ground-based measurements are taken in dry conditions in order ...to have a consistency within networks. The dependence of the various aerosol optical characteristics (e.g. aerosol absorption, scattering, backscattering or extinction coefficients) on relative humidity has therefore to be established in order to determine their values in the atmosphere, where relative humidity can reach high values. We calculated mean monthly diurnal values of the aerosol hygroscopic growth factor at 90% relative humidity GF(90) based on measurements performed at the atmospheric research station in Ispra (Italy) with a Hygroscopicity Tandem Differential Mobility Analyzer over eight months in 2008 and 2009. Particle hygroscopicity increases with particle dry diameter ranging from 35 to 165 nm for all seasons. We observed a clear seasonal variation in GF(90) for particles larger than 75 nm, and a diurnal cycle in spring and winter for all sizes. For 165 nm particles, GF(90) averages 1.32 0.06. The effect of the particle hygroscopic growth on the aerosol optical properties (scattering, extinction, absorption and backscatter coefficients, asymmetry parameter and backscatter faction) was computed using the Mie theory, based on data obtained from a series of instruments running at our station. We found median enhancement factors (defined as ratios between the values of optical variables at 90% and 0% relative humidity) equal to 1.1, 2.1, 1.7, and 1.8, for the aerosol absorption, scattering, backscattering, and extinction coefficients, respectively. All except the absorption enhancement factors show a strong correlation with the hygroscopic growth factor. The enhancement factors observed at our site are among the lowest observed across the world for the aerosol scattering coefficient, and among the highest for the aerosol backscatter fraction.
Remote sensing represents a prospective tool to complement in situ measurements for monitoring particulate matter air pollution. The remotely sensed aerosol metric which is generally related to the ...in situ measured particulate matter mass concentration (PM) is the aerosol optical thickness (AOT), the vertically integrated aerosol extinction that optically quantifies the aerosol load in the whole atmospheric column. Annual variations in AOT and PM can follow very different patterns, indicating that the AOT‐to‐PM conversion is not straightforward. In the Po Valley, northern Italy, AOT and PM seasonal cycles exhibit a marked phase shift. Making use of aerosol extinction vertical profiles derived from continuous aerosol lidar measurements, we further searched through the AOT‐to‐PM10 relationship in this region. On the basis of a 2‐year (2006–2007) multisensor database, including remote sensing observations from ground and space and in situ measurements, this study: (1) discloses for the first time the height‐resolved seasonal variability of the aerosol optical properties in the Po Valley, (2) demonstrates and quantifies the crucial role of the aerosol vertical distribution in the AOT‐to‐PM relationship in this region, (3) suggests a methodology to rescale AOT to ground‐level aerosol extinction values that correlate with PM concentration and from which PM10 annual average and exceedances frequency of daily limit value can be retrieved within a few percentage points, and (4) highlights that the hygroscopic growth of the particles in the atmosphere is a critical factor for comparing in situ‐measured to remotely sensed aerosol properties.
Abstract This longitudinal study investigated the 3-D facial soft-tissue response to transverse palatal bone-anchored osteodistraction in 18 adult patients. Laser-scanned facial surface data were ...obtained for all patients before (T0 ), 6 months (T1 ) and 1 year (T2 ) after transverse palatal distraction. The averaged facial morphologies at T0 , T1 and T2 were calculated and compared. Sagittal and vertical measurements were obtained from lateral cephalograms to evaluate skeletal and dental movements. Pre- and immediate post-distraction dental casts were used to investigate transverse maxillary movements. Cutaneous changes were mainly observed in the paranasal regions and cheeks, in the range 1–3 mm, reflecting the underlying increase in the maxillary width. A significant enlargement of the nasal base was also demonstrated. The absolute magnitude of these facial changes was limited but clinically relevant. Variable skeletal movements were observed. These were of low magnitude and no systematic tendency could be demonstrated statistically. Significant changes were documented only with regard to orthodontic repositioning of the upper and lower incisors. The mean transverse increases in the maxillary dental arch were 6.7 mm at the intercanine, 6.8 mm at the interpremolar, and 6.1 mm at the intermolar levels.
We analyse the differences in the financial debt level of firms both in market-oriented systems (the US, the UK) and bank-oriented systems (Germany, France and Italy) on a sample of 3360 listed ...companies between the period 2006 and 2010. Results indicate that the debt level is significantly higher in market-oriented systems when compared to the book value of equity. We find confirmation that Book-to-Market (BTM) cannot explain the debt level in bank-oriented systems but, contrary to reference literature, we observe that the BTM ratio has a negative influence on the debt level in market-oriented systems, especially in the United States. We claim different reasons to explain the evidence: (i) the financing standards of market-oriented countries, with an inflationary effect of market values on debt; (ii) an underlying activity for ownership protection and (iii) the unfavourable conditions of stock market over the years of the financial crisis that reduced the convenience of equity issuance.
PDF
