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Advanced aspects of radiation protection in the use of particle accelerators in the medical field / Aspetti avanzati di radioprotezione nell'uso di acceleratori di particelle in campo medicoInfantino, Angelo <1985> 29 April 2015 (has links)
In this work, the well-known MC code FLUKA was used to simulate the GE PETrace cyclotron (16.5 MeV) installed at “S. Orsola-Malpighi” University Hospital (Bologna, IT) and routinely used in the production of positron emitting radionuclides. Simulations yielded estimates of various quantities of interest, including: the effective dose distribution around the equipment; the effective number of neutron produced per incident proton and their spectral distribution; the activation of the structure of the cyclotron and the vault walls; the activation of the ambient air, in particular the production of 41Ar, the assessment of the saturation yield of radionuclides used in nuclear medicine. The simulations were validated against experimental measurements in terms of physical and transport parameters to be used at the energy range of interest in the medical field.
The validated model was also extensively used in several practical applications uncluding the direct cyclotron production of non-standard radionuclides such as 99mTc, the production of medical radionuclides at TRIUMF (Vancouver, CA) TR13 cyclotron (13 MeV), the complete design of the new PET facility of “Sacro Cuore – Don Calabria” Hospital (Negrar, IT), including the ACSI TR19 (19 MeV) cyclotron, the dose field around the energy selection system (degrader) of a proton therapy cyclotron, the design of plug-doors for a new cyclotron facility, in which a 70 MeV cyclotron will be installed, and the partial decommissioning of a PET facility, including the replacement of a Scanditronix MC17 cyclotron with a new TR19 cyclotron. / In questo lavoro, il codice Monte Carlo (MC) FLUKA è stato utilizzato per simulare il ciclotrone GE PETtrace (16.5 MeV) installato presso l’azienda ospedaliera “S. Orsola-Malpighi” (Bologna, IT), quotidianamente utilizzato per la produzione di radiofarmaci PET. Le simulazioni sono state effettuate per valutare diversi fenomeni e quantità d’interesse radiologico tra cui l’equivalente di dose ambientale nell’intorno dell’acceleratore, il numero di neutroni emessi per protone incidente e la loro distribuzione spettrale, l’attivazione dei componenti del ciclotrone e delle pareti del bunker, l’attivazione dell’aria interna al bunker ed in particolare la produzione di 41Ar, la resa a saturazione di radionuclidi d’interesse in medicina nucleare. Le simulazioni sono state validate, in termini di parametri fisici e di trasporto da utilizzare nel range energetico caratteristico delle applicazioni mediche, con una serie di misure sperimentali.
Il modello MC validato è stato quindi applicato ad altri casi pratici quali lo studio di fattibilità della produzione diretta in ciclotrone di 99mTc, la produzione di radionuclidi ad uso medico con il ciclotrone TR13 (13 MeV) installato presso il centro di ricerca TRIUMF (Vancouver, CA), la progettazione completa del nuovo centro PET dell’ospedale “Sacro Cuore-Don Calabria” di Negrar (Verona, IT), incluso il ciclotrone ACSI TR19 (19 MeV), lo studio del campo di dose nell’intorno di un sistema di selezione dell’energia (degrader) di un ciclotrone per terapia, la progettazione di specifiche “porte a tappo” per un sito di produzione di radionuclidi ad uso medico, in cui verrà installato un ciclotrone da 70 MeV e sei diverse beam line, e per il parziale decommissioning di un centro PET e la sostituzione di un ciclotrone Scanditronix MC17 (17 MeV), attualmente installato, con una nuova unità TR19.
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Occupational exposure to fluorinated ski waxNilsson, Helena January 2012 (has links)
Per- and polyfluorinated substances (PFAS) are used in the production of ski wax to reduce the friction between the snow and the ski. In this occupational study of ski wax technicians’ exposure to PFAS and particulate aerosol we have collected whole blood (wb) (n =94), air (n =84) and aerosol (n =159) samples at World Cup events from 2007-2011. We have analysed the blood, air and aerosol with respect to 13 perfluorocarboxylic acids (PFCAs), 4 perfluorosulfonic acids (PFSAs), 3 fluorotelomer alcohols (FTOHs), 3 fluorotelomer acids (FTCAs) and 3 unsaturated fluorotelomer acids (FTUCAs). Further, we assessed the exposure to 3 particulate aerosol fractions (inhalable, respirable and total aerosol) in air. In comparison to a general population, several of the PFCA blood levels are elevated in the technicians’, primarily erfluorooctanoate (PFOA) and perfluorononate (PFNA) with concentrations up to 628 and 163 ng/mL wb, respectively. Further, we detected FTUCAs and FTCAs in the blood, suggesting biotransformation of FTOHs to PFCAs. The metabolites 5:3 and 7:3 FTCA were detected in all blood samples at levels up to 6.1 and 3.9 ng/mL wb. Levels of perfluorohexadecanoic acid PFHxDA) and perfluorooctadecanoic acid (PFOcDA) were detected in the technician’s blood at mean concentration up to 4.22 ng/mL wb and 4.25 ng/mL wb. The FTOH levels in air of the wax cabin during work ranged up to 997 000 ng/m3 (average=114 000 ng/m3 ) and PFOA up to 4 890 ng/m3 (average= 526 ng/m3 . FTOHs were not detected in aerosols but PFOA showed average levels of 12 000 ng/m3 (range=1 230- 46 900 ng/m3 ). The occupational exposure limit (OEL) of 2 mg/m3 was exceeded in 37% of the personal measurements with aerosol concentrations up to 15 mg/m3 . Keywords : Perfluorinated, polyfluorinated, FIS, occupational exposure, ski wax, iotransformation, metabolism, fluorotelomer alcohol, fluorotelomer acid, aerosol, dust, UPLC/MS-MS, GC/MS-MS
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Analýza uplatnění absolventů informatiky FIS VŠE / Analysis of Use of Graduates from Faculty of Informatics and Statistics University of Economics in PragueŘepík, Martin January 2011 (has links)
This thesis deals with the analysis of informatics fields of study taught at public universities in the Czech Republic. The aim is to describe degree courses and their comparison with the teaching of informatics at the Faculty of Informatics and Statistics of the University of Economics in Prague. At the end the courses taught at FIS University of Economics in Prague are confronted with the statistics of graduates based on information from a database of personal agency Grafton Recruitment. Based on this are defined recommendations for further improvement of teaching of informatics at FIS University of Economics in Prague.
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Johann Nepomuk Hummels Sonate in fis-Moll Op. 81 – Studien zu Entstehungshintergrund, Rezeption und formaler StrukturTiemeyer, Daniel 29 October 2020 (has links)
The article examines the significance of one of Johann Nepomuk Hummel’s masterpieces. First, it highlights the circumstances of its production and the contemporary critical acclaim in the AmZ. In a second step, Robert Schumann’s involvement with this work is shown. In his journal, the sonata of Hummel is mentioned several times which indicates the engagement of the young piano discipline. In a short article, published in the NZfM in the year 1839, Schumann links this sonata with the compositional “way of Mozart” and thus gives an important hint to the formal design of the piece itself. Aspects of formal organization and structure of this sonata are analyzed and presented in the third part of the essay. In opposition to Beethoven’s motivic development, Hummel pursues another strategy of formal structure by stringing together each of the segments and themes. Thus, the focus shifts from a dynamic design of sonata-form to a more epic layout of the piece. Additionally, technical development and innovations concerning piano techniques and virtuosity are examined.
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Konzepte großmaßstäbiger BodenkartenSteininger, Michael, Wurbs, Daniel, Möller, Markus, Gerstmann, Henning 22 July 2020 (has links)
Auf Basis der Daten des Fachinformationssystems Boden, der Bodenschätzung und weiterer Informationen aus einer digitalen Reliefanalyse und der Landnutzung wurden Methoden zur digitalen Erstellung von großmaßstäbigen Bodenkarten (digital soil mapping) Sachsens getestet. Die Publikation beschreibt die Aufbereitung der Grundlagendaten sowie die Anwendung der Methoden.
Redaktionsschluss: 22.01.2020
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Spatial Patterns of Molecular Traits in Bacterial Genomes / Bacterial Molecular Properties and Genomic PositionLato, Daniella Fiora January 2021 (has links)
The placement of genetic information within bacterial genomes is intentionally organized, creates predictable gradients of molecular properties along the origin-terminus of replication axis. Previous studies have reported that genes located near the origin of replication generally have a higher expression level, increased dosage, and are more conserved than genes located near the terminus of replication. Additionally, substitution rates usually increases with increasing distance from the origin of replication. However, the constant reorganization of genetic information is often overlooked when considering spatial molecular trends.
Here, we explore the interplay of genomic reorganization along the origin and terminus of replication axis of gene expression and substitutions in Escherichia coli, Bacillus subtilis, Streptomyces, and Sinorhizobium meliloti. Using ancestral reconstruction to account for genome reorganization, we demonstrated that the correlation between the number of substitutions and distance from the origin of replication is significant but small and inconsistent in direction. In another study, we looked at the overall expression levels of all genes from the same bacteria, and
confirmed that gene expression tends to decrease when moving away from the origin of replication.
We looked specifically at how inversions - one type of genomic reorganization - impact gene expression between closely related strains of E. coli. Some inversions cause significant differences in gene expression compared to non-inverted regions, however, the variation in expression does not significantly differ between inverted and non-inverted regions. This change in gene expression may be due to the expression regulation properties of two nucleoid proteins, Histone-like Nucleoid-Structuring (H-NS) and Factor for inversion stimulation (Fis), who’s binding sites had a significant positive correlation with inverted regions.
In conclusion, we highlight the impact that genomic rearrangements and location have on molecular trends in bacteria, illustrating the importance of considering spatial trends in molecular evolutionary analysis, and to ensure accurate generalization of previously determined trends. Assuming that molecular trends are exclusively in one direction can be problematic. / Dissertation / Doctor of Philosophy (PhD)
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Modeling the Urban Boundary Layer in Complex TerrainZonato, Andrea 06 December 2021 (has links)
In this work, various topics regarding (urban) boundary simulations for a city situated in the alps will be discussed. First of all, we will present novel parameterization adopted to take into account the effect of mitigation strategies, such as rooftop Photovoltaic Panels and Green Roofs, on the urban environment, and their effect on average temperature and energy consumption by buildings. Secondly, a new turbulence closure, that adopts a diagnostic equation for dissipation rate, and then independent on mixing length scales, will be introduced. The new turbulence closure, implemented into the WRF model, has been coupled with multi-layer urban parameterization schemes and compared with high-resolution CFD and LES simulations.
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Imaging Chloride Homeostasis in NeuronsArosio, Daniele January 2017 (has links)
Intracellular chloride and pH are fundamental regulators of neuronal excitability and they are often co-modulated during excitation-inhibition activity. The study of their homeostasis requires simultaneous measurements in vivo in multiple neurons. Combining random mutagenesis screening, protein engineering and two-photon-imaging this thesis work led to the discovery of new chloride-sensitive GFP mutants and to the establishment of ratiometric imaging procedures for the quantitative combined imaging of intraneuronal pH and chloride. These achievements have been demonstrated in vivo in the mouse cortex, in real-time monitoring the dynamic changes of ions concentrations during epileptic-like discharges, and in glioblastoma primary cells, measuring osmotic swelling responses to various drugs treatment.
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Assessing solar radiation components over the alpine region Advanced modeling techniques for environmental and technological applications.Castelli, Mariapina January 2015 (has links)
This thesis examines various methods for estimating the spatial distribution of solar radiation, and in particular its diffuse and direct components in mountainous regions. The study area is the Province of Bolzano (Italy). The motivation behind this work is that radiation components are an essential input for a series of applications, such as modeling various natural processes, assessing the effect of atmospheric pollutants on Earth's climate, and planning technological applications converting solar energy into electric power. The main mechanisms that should be considered when estimating solar radiation are: absorption and scattering by clouds and aerosols, and shading, reflections and sky obstructions by terrain. Ground-based measurements capture all these effects, but are unevenly distributed and poorly available in the Italian Alps. Consequently they are inadequate for assessing spatially distributed incoming radiation through interpolation. Furthermore conventional weather stations generally do not measure radiation components. As an alternative, decomposition methods can be applied for splitting global irradiance into the direct and diffuse components. In this study a logistic function was developed from the data measured at three alpine sites in Italy and Switzerland. The validation of this model gave MAB = 51 Wm^-2, and MBD = -17 Wm^-2 for the hourly averages of diffuse radiation. In addition, artificial intelligence methods, such as artificial neural networks (ANN), can be applied for reproducing the functional relationship between radiation components and meteorological and geometrical factors. Here a multilayer perceptron ANN model was implemented which derives diffuse irradiance from global irradiance and other predictors. Results show good accuracy (MAB in [32,43] Wm^-2, and MBD in [-7,-25] Wm^-2) suggesting that ANN are an interesting tool for decomposing solar radiation into direct and diffuse, and they can reach low error and high generality. On the other hand, radiative transfer models (RTM) can describe accurately the effect of aerosols and clouds. Indeed in this study the RTM libRadtran was exploited for calculating vertical profiles of direct aerosol radiative forcing, atmospheric absorption and heating rate from measurements of black carbon, aerosol number size distribution and chemical composition. This allowed to model the effect of aerosols on radiation and climate. However, despite their flexibility in including as much information as available on the atmosphere, RTM are computationally expensive, thus their operational application requires optimization strategies. Algorithms based on satellite data can overcome these limitations. They exploit RTM-based look up tables for modeling clear-sky radiation, and derive the radiative effect of clouds from remote observations of reflected radiation. However results strongly depend on the spatial resolution of satellite data and on the accuracy of the external input. In this thesis the algorithm HelioMont, developed by MeteoSwiss, was validated at three alpine locations. This algorithm exploits high temporal resolution METEOSAT satellite data (1 km at nadir). Results indicate that the algorithm is able to provide monthly climatologies of both global irradiance and its components over complex terrain with an error of 10 Wm^-2. However the estimation of the diffuse and direct components of irradiance on daily and hourly time scale is associated with an error exceeding 50 Wm^-2, especially under clear-sky conditions. This problem is attributable to the low spatial and temporal resolution of aerosol distribution in the atmosphere used in the clear-sky scheme. To quantify the potential improvement, daily averages of accurate aerosol and water vapor data were exploited at the AERONET stations of Bolzano and Davos. Clear-sky radiation was simulated by the RTM libRadtran, and low values of bias were found between RTM simulations and ground measurements. This confirmed that HelioMont performance would benefit from more accurate local-scale aerosol boundary conditions. In summary, the analysis of different methods demonstrates that algorithms based on geostationary satellite data are a suitable tool for reproducing both the temporal and the spatial variability of surface radiation at regional scale. However better performances are achievable with a more detailed characterization of the local-scale clear-sky atmospheric conditions. In contrast, for plot scale applications, either the logistic function or ANN can be used for retrieving solar radiation components.
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Isolated objects in quadratic gravitySilveravalle, Samuele Marco 07 June 2023 (has links)
Quadratic curvature terms are commonly introduced in the action as first-order corrections of General Relativity, and, in this thesis, we investigated their impact on the most simple isolated objects, that are the static and spherically symmetric ones. Most of the work has been done in the context of Stelle's theory of gravity, in which the most general quadratic contractions of curvature tensors are added to the action of General Relativity without a cosmological constant. We studied this theory's possible static, spherically symmetric and asymptotically flat solutions with both analytical approximations and numerical methods. We found black holes with Schwarzschild and non-Schwarzschild nature, naked singularities which can have either an attractive or repulsive gravitational potential in the origin, non-symmetric wormholes which connects an asymptotically flat spacetime with an asymptotically singular one, and non-vacuum solutions modeled by perfect fluids with different equations of state. We described the general geometrical properties of these solutions and linked these short-scale behaviors to the values of the parameters which characterize the gravitational field at large distances. We studied linear perturbations of these solutions, finding that most are unstable, and presented a first attempt to picture the parameter space of stable solutions. We also studied the Thermodynamics of black holes and described their evaporation process: we found that either evaporation leads black holes to unstable configurations, or the predictions of quadratic gravity are unphysical. We also considered the possibility of generalizing Stelle's theory by removing the dependence from the only mass-scale present by including a new dynamical scalar field, making the theory scale invariant. Having a more complex theory, we did not investigate exotic solutions but limited ourselves to the impact of the new additional degrees of freedom on known analytical solutions. It was already known that in a cosmological setting this theory admits a transition between two de Sitter configurations; we analyzed the same problem in the context of static and spherically symmetric solutions and found a transition between two Schwarzschild-de Sitter configurations. In order to do that, we studied both linear perturbations and the semiclassical approximation of the path integral formulation of Euclidean quantum gravity. At last, we tried to extract some phenomenological signatures of the exotic solutions. In particular, we investigated the shadow of an object on background free-falling light, and a possible way of determining the behavior close to the origin using mass measurements that rely on different physical processes. We show that, whenever these measurements are applied to the case of compact stars, in principle it could be possible to distinguish solutions where different equations of state describe the fluid.
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