SIGNALING STUDIES IN THE EMERGING KIWIFRUIT PATHOGEN Pseudomonas syringae pv. actinidiaeSree Gowrinadh Javvadi
, 2017, doktorska disertacija
Opis: In the past two decades emerging and re-emerging plant pathogens have caused new threats to the
production of several economically important crops, one among them is P. syringae pv. actinidiae
(PSA) which causes canker or leaf spot on kiwifruit plants. PSA enters plant through wounds and
remains dormant in cortex tissue of the branches, and spreads in the tissue to cause severe
symptoms from winter to early spring. The disease can be visualized by brown discoloration of
buds, dark brown angular spots surrounded by yellow haloes on leaves, cankers with white to
reddish (oxydation) exudate on twigs and trunks, fruit collapse, wilting and eventually plant
mortality. Current control methods have their own significance in disease control, however there
is considerable lack of clear understanding of PSA pathogenicity. Virulence of plant pathogens
often relies on the synchronized/coordinated expression of pathogenicity factors via quorum
sensing (QS). Therefore, investigations on QS in PSA may lead to develop novel disease control
strategies and reliable methods to curb the disease. It is currently unknown whether PSA produces
a QS signal molecule thus the aim of this thesis is to investigate whether PSA possesses a QS
system. As genome mining did not reveal the presence of any currently known QS system, this
study initially by metabolomics was aimed at identifying potentially low molecular weight
secondary metabolite QS molecules produced by PSA. Azelaic acid was discovered to be produced
by PSA, this is the first report of azelaic acid production by bacteria. The characterization and
possible role of azelaic acid in QS is presented. Since azelaic acid is ubiquitous in nature, in
addition to determining its biological role, the catabolism of azelaic acid in bacteria using the
efficient degrader Pseudomonas nitroreducens DSM 9128 was also studied.
Ključne besede: Quorum sensing, Azelaic acid, Metabolomics, Catabolism
Objavljeno: 19.12.2017; Ogledov: 130; Prenosov: 7
Polno besedilo (4,41 MB)
Development of Slovenian linguistic terminology in Slovenian grammars in the 18th and 19th centuriesMitja Trojar
, 2017, doktorska disertacija
Opis: The dissertation describes the problems of metalanguage and peculiarities of linguistic terminology. Special attention is paid to autonymy, which plays a central role in metalanguage.
The dissertation presents the life and work of Eugen Wüster, the founder of traditional terminology, and the principal tenets of his approach to terminology. Traditional terminology is critically evaluated; we show its inability to describe linguistic terminology: it lacks a coherent theoretical apparatus enabling description, its semantic theory is based on classical definition, which in many cases cannot be formulated, which means that traditional terminology is also unable to account for translation of terms and comparison of concepts across different concept systems.
A sample of 50 basic linguistic terms from 19 grammars from the 18th, 19th and 20th centuries was used to examine the development of Slovenian linguistic terminology and to ascertain who played the most important role in it. The research shows that Anton Janežič made by far the most important contribution to Slovenian linguistic terminology: he introduced 27 terms (in both his 1854 and 1863 grammars), which represents 54% of the 50 terms retained by Breznik.
The dissertation also contains some remarks on the semantics of linguistic terms.
The scientific relevance of the thesis lies in its critical evaluation of traditional terminology; the results show that traditional terminology faces a number of theoretical problems; a new theory of terminology is needed, one that will be able to account for translation of terms as well as for diachronic conceptual change. The scientific relevance of results related to the second research goal (determining the contributions of individual grammarians to the development of Slovenian linguistic terminology) consists in proposing a model of research that could be used in order to measure the influence of a specific author on the introduction of new terms.
Ključne besede: metalanguage, linguistic terminology, history of terminology, development of linguistic terminology, diachrony
Objavljeno: 27.11.2017; Ogledov: 160; Prenosov: 51
Polno besedilo (4,06 MB)
THE IMPACT OF EUROPEANISATION ON THE NATURE PROTECTION SYSTEM OF SELECTED COUNTRIES OF SOUTHEAST EUROPE ON THE EXAMPLE OF THE ESTABLISHMENT OF MULTI-LEVEL GOVERNANCE SYSTEM OF NATURA 2000Aleksandar Šobot
, 2017, doktorska disertacija
Opis: The Europeanisation of Southeastern Europe led to the pre-accession and accession process of joining countries of the former Yugoslavia to the European Union. Slovenia's accession to the formal process of accession to the European Union started in 1999. This process lasted until 2003. Then, in 2004, Slovenia joined the European Union. Croatia's access to the formal process of accession to the European Union started in 2003. This process lasted until 2012. Then, in 2013, Croatia joined the European Union. Bosnia and Herzegovina entered the pre-accession process with the process of stabilization and association with the European Union, which lasted from 1999 to 2015. Then, in 2016, Bosnia and Herzegovina officially submitted its application for European Union membership.
This paper examines the impact of the Europeanisation during this period on the nature protection system in the case of Slovenia, Croatia and Bosnia and Herzegovina while establishing multi-level governance system of protected areas within NATURA 2000 network. The analysis of the establishment of multi-level governance system is performed according to the morphogenetic model in three cycles as a case study. The case study is organized with the help of interviews and desk analysis of the relevant documents. In the first cycle were explained the projects/process of implementation of NATURA 2000 in Slovenia, Croatia and Bosnia and Herzegovina and its changing impacts on national legislation in the area of nature protection (environmental policy). The second cycle explains the role of the main actors in the establishment of multi-level governance system of NATURA 2000 such as the European Union institutions, competent ministries, national parks and non-governmental organisations (environmental polity). The third cycle outlines the contribution to the establishment of multi-level governance system of NATURA 2000 on the nature protection systems of Slovenia, Croatia and Bosnia and Herzegovina and their future challenges (environmental politics).
The main conclusions point to the major changes in the nature protection systems of Slovenia, Croatia and Bosnia and Herzegovina during the process of implementation/establishing multi-level governance system of NATURA 2000. Main legal and institutional points of implementation of NATURA 2000 with all positive and negative sides are presented here. In the end, implementation of the European ecological network NATURA 2000 in Slovenia is marked as an excellent example with significant changes in legal (laws on nature protection) and institutional (transformation of governmental institutions, establishment of new institutions and inclusion of NGOs in decision making) framework. This process in Croatia was marked as good with significant changes in legal (laws on nature protection, adopting new strategy of sustainable development) and institutional (transformation of governmental organisation, establishment of new institutions and inclusion of NGOs in decision making) framework. This process in Bosnia and Herzegovina was marked as satisfactory with significant changes in legal (adopting new entity laws on nature protection) and institutional (adopting coordination mechanism for inter-entity and inter-institutional cooperation as well as inclusion of NGOs in decision making) framework.
There are also significant weak points during the process of N2000 in all three countries (such as the late change of national legislative, not following the national legislative from governmental institution and not including NGOs into decision making), which during the proces of implementation of N2000 (for Croatia and Slovenia) or the process of preparation of implementation (for Bosnia and Herzegovina) cause significant problems, that call for action in the future in order to improve governance of natural resources /NATURA 2000. On the other hand, these points could serve as an example for all countries that underwent/or should undergo ...
Ključne besede: The Europeanisation of Southeastern Europe, the pre-accession process, the accession process, Slovenia, Croatia, Bosnia and Herzegovina, the nature protection system, NATURA 2000 protected areas
Objavljeno: 06.11.2017; Ogledov: 118; Prenosov: 39
Polno besedilo (2,77 MB)
Study of the properties of air flow over orographic barrierMaruška Mole
, 2017, doktorska disertacija
Opis: Earth’s atmosphere is a complex system. All weather phenomena take place in its lowest layer, the troposphere, which is strongly influenced by human activities and the underlying surface orography. A good example of the influence the orography has on the behavior of air flows is the appearance of strong north-east downslope wind in Vipava valley, called Bora. Numerical models used to analyze flows in complex terrain need meteorological data both for setting the initial conditions and the verification of modeling results. Obtaining spatial distributions of meteorological observables can be challenging, especially in the case of strong winds, such as Bora, where traditional methods may be inadequate due to prohibitive wind speeds. In most cases, vertical properties of the atmosphere can be obtained using remote sensing techniques. Contrary to vertical profile measurements with traditional methods, remote sensing techniques do not require the measuring device to be placed within the flow and are therefore more appropriate for measurements in severe weather conditions such as strong winds.
The aim of this thesis is a detailed analysis of wind and tropospheric structure properties in and above the Vipava valley in a variety of typical atmospheric conditions, including strong wind events. It employs a combination of high resolution wind and lidar data in addition to standard meteorological measurements.
In Ajdovščina, there are four predominant wind directions, two of them directly connected to Bora. In the case of Bora, periodicity analysis of wind data from Ajdovščina yielded a range of possible wind gust periods between 1 and 7 minutes. The periods were not stable, with the periodogram less noisy for stable wind directions. Wavelike structures were found to be present in the troposphere in half of the investigated cases, regardless of the presence of Bora. In statically stable conditions, gravity waves propagated throughout
the planetary boundary layer (PBL). In the case of Bora, the PBL experienced oscillations with periods between 1 and 2 minutes. A shear layer was present above the PBL, causing Kelvin-Helmholtz waves at its boundaries with periods ranging from 3 to 6 minutes. In some cases, periodic structures were observed above the shear layer as well, which were found to have longer periods than those within the PBL.
Ključne besede: remote sensing, Vipava valley, wind properties, Bora, wind gusts, wind periodicity, tropospheric structures, Kelvin-Helmholtz waves
Objavljeno: 18.09.2017; Ogledov: 351; Prenosov: 20
Polno besedilo (45,11 MB)
Meshless modeling of thermo-mechanics of low-frequency electromagnetic direct chill castingBoštjan Mavrič
, 2017, doktorska disertacija
Opis: The aim of this dissertation is to devise a meshless model describing the thermomechanical phenomena, which occur during DC casting of aluminium alloys under the influence of electromagnetic stirring. The thermoemchanical phenomena are important, because they can cause several type of defects, which can significantly deteriorate the quality of the resulting billet. The two most important of them are the hot tearing, which causes cracks to appear in the mushy zone, and the porosity, which demonstrates itself as micrometer sized voids in the microstructure of the billet.
To calculate the stresses and strains, a computational model of the stationary state of the process, stated in axial symmetry, is formulated. It uses Eulerian formulation by fixing the computational domain to the mold of the casting device allowing the material to move through the computational domain. The stresses are calculated from the stress equilibrium equations. The small strain approximation is used to consider the three contributions to strain. The strain consists of the thermal strain, which is caused by the inhomogeneous thermal profile in the billet, the viscoplastic strain, which is caused by the irreversible deformation because of the large stresses occurring in the billet, and the elastic strain.
The spatial discretization of the governing equations is performed by local radial basis function collocation method (LRBFCM) and the temporal discretization is achieved by the method of lines with implicit Euler formula. The method used for spatial discretization uses radial basis functions augmented by monomials to approximate the solution values on localized stencils. This approximation is used to construct the discretization coefficients of the differential operators present in the model. A flexible framework for formulation of multiphysics problems is developed to use the obtained discretization coefficients to construct the temporal discretization of the governing equations. The node arrangement, on which the spatial discretization is performed, was generated by a point-repel algorithm.
The performance of the method is tested on several benchmark test cases. The accuracy of the discretization is estimated by comparing the analytic and the numerical solution to several stationary problems in thermomechancis. Of special interest is the performance of the method with respect to the choice of the shape parameter, which determines the spatial scale of the radial basis functions. Besides this, the dependence of the condition number of the interpolation matrix on the shape parameter is studied. The condition number is found fit to replace the condition number as the shape-determining free parameter of the method.
The implementation of the solver of time dependent problems is tested on problem of thermoelasticity, which couples the thermal transport with the elastic waves. The results of the problem are compared with the finite element method, showing good agreement of the two methods. The results are also compared with the results obtained by meshless local Petrov-Galerkin method and the proposed local collocation method demonstrated significantly better solution quality in the studied case.
The performance of the solver used to solve the system of nonlinear equations given by the viscoplastic constitutive equations is estimated on a quasi zero-dimensional problem. The results are found to match perfectly. Solution of a more complicated problem is obtained with the proposed method and the finite-element method, both methods giving practically the same solution, although some serious limitations of the chosen finite element solver are exposed during the selection of the problem parameters.
Finally, the devised method is applied to the problem of DC casting of aluminium alloys. The thermomechanical model relies on a model of heat and mass transfer to obtain the input fields needed in the solver. The required fields are: temperature, pressure, liquid
Ključne besede: thermomechanics, viscoplasticity, aluminium alloys, direct-chill casting, electromagnetic stirring, hot tearing, porosity, meshless methods, local collocation method, radial basis functions, shape parameter
Objavljeno: 28.06.2017; Ogledov: 548; Prenosov: 16
Polno besedilo (21,30 MB)
RE-CONCEPTUALIZATION OF THE CONSERVATION THEORY FOR THE MANAGEMENT OF ARCHAEOLOGICAL HERITAGEUsman Ali
, 2017, doktorska disertacija
Opis: ver the last few decades, the concept of “authenticity” has commonly been used as a criterion for heritage conservation and management in various regions around the world. In 1994, ICOMOS adopted the Nara document on Authenticity as an international recommendation to draw the attention of policy and decision makers on the values of cultural heritage, stressing on interdisciplinary of approaches. Interdisciplinary research of heritage studies includes analysis and evaluation methods to redefine the theories and methodologies of heritage preservation and management in different contexts. But, when dealing with Archaeological Heritage Management, various difficulties emerge in the adoption of prescribed criteria for heritage conservation and management.
The aim of this research is to examine and evaluate the compatibility and potential adaptation of these significant criteria from the Heritage International practice (I.e. UNESCO), including the spheres of law and philosophy, in the Management of Archaeological Heritage. Consequently, this dissertation is articulating according to the following concepts:
1. UNESCO already prescribed parameters and criteria of conservation and management of cultural heritage, but their full applicability on Archaeological Heritage Management should be verified;
2. The level of similarities and differences between Cultural and Archaeological Heritage in the conservation and management process should be discussed to highlight potential new research channels;
3. Is the adoption of the concept of Authenticity as a criterion, prescribed in UNESCO Operational Guideline, compatible enough to be applied to the Management of Archaeological Heritage or not?
4. Archaeological practice as a source of information provides various data and parameters. Are these attributions determining the management?
This dissertation concludes that thematic divisions of heritage studies foster and formulate various models and concepts (implicitly and explicitly), which determine many substantial criteria and integrated factors for the sustainability of archaeological heritage. These criteria and factors give
importance to the common theoretical and methodological research in archaeological heritage conservation theory and practice.
Ključne besede: World Heritage Studies, Archaeological Heritage Management, Authenticity, Heritage Conservation, Archaeological Theories, Heritage International Doctrine.
Objavljeno: 22.06.2017; Ogledov: 595; Prenosov: 36
Polno besedilo (2,37 MB)
Synthesis and characterization of metal/semiconductor nanocomposites for photocatalysisTina Mavrič
, doktorska disertacija
Opis: The doctoral dissertation focused on improving photocatalytic activity of nanopowdered ZnO by constructing I) Metal-Semiconductor and II) Semiconductor-Semiconductor heterostructures. Both heterostructure types have been reported to have a beneficial effect on photocatalytic efficiency. For the first part (I) Ag/ZnO nanocomposite was synthesized. Here we investigated an influence of polyvinylpyrrolidone (PVP) addition during the synthesis on the particle properties and their photoactivity. The second part (II) describes procedure development of ZnO based semiconductor-semiconductor composite that resulted in synthesis of highly efficient ZnO/CuWO4 composite.
Ag/ZnO nanocomposite was synthesized from precursors in ethylene glycol (EG) in a hydrothermal reactor at 180 °C for 3h. No further thermal treatment was required after the synthesis since all samples showed good crystallinity. Silver precursor loading was 2.7 wt%, because this amount has shown the best photoactivity in preliminary sample testings. Two separate batches of Ag/ZnO nanopowders were prepared, one with addition of PVP, one without (labelled Ag/ZnO and Ag/ZnO*, respectively). All powders were in nanometer range, TEM images showed a major difference between the samples with and without PVP. While Ag nanoparticles were deposited uniformly over ZnO, Ag/ZnO* exhibited a substantial agglomeration of Ag. The photocatalytic efficiency was assessed under UV-Vis light. Ag/ZnO reached complete decolourization of 10–5 M methyl orange (MO) already in 80 min after the beginning of irradiation. The calculated degradation rate constant (k) for the Ag/ZnO was almost 2-times larger than for TiO2 P25 and 4-times larger than for ZnO. Ag/ZnO* also showed higher activity than pure ZnO*, but was inferior to Ag/ZnO (1.6-times of Ag/ZnO*). A reusability test performed on Ag/ZnO showed an excellent photoactivity of reused powders; second and third cycle exhibited higher photoactivity than the first cycle. The supreme photocatalytic activity of Ag/ZnO was also confirmed by degradation of terephthalic acid.
To develop an efficient semiconductor-semiconductor heterostructure we have synthesized a combination of several materials with ZnO. We performed preliminary photocatalytic tests in order to assess the functionality of these heterostructures. The tested systems were the following: ZnO/MWCNT, ZnO/GO, ZnO/SiC, ZnO/Co3O4, ZnO/AgVO3. The synthesis of heterostructures was done via hydrothermal synthesis. The commercial or synthesized powers were dispersed together with the ZnO precursor in EG medium (180 °C/3h). The aim was to obtain higher photoactivity than that of pure ZnO. None of these systems was able to outperform pure ZnO.
ZnO/CuWO4 system has, however, significantly improved ZnO photoactivity. Several synthesis routes were investigated, including the influence of different structure directing agents (PVP, CTAB, starch). The best performing system was obtained by separate hydrothermal synthesis of ZnO and CuWO4 in water with PVP. XRD analysis confirmed that to obtain the crystalline CuWO4 thermal treatment (500 °C) is needed. The heterostructure was also synthesized in ethanolic solution. ZnO particles were in a nanometer range, CuWO4 were larger and ranged from 200 to 400 nm. CuWO4 has successfully decreased the charge recombination in ZnO, which was confirmed by transient absorption spectroscopy studies. The photocatalytic activity was assessed for both MO and TPA (10–4 M) degradation. The ZnO/CuWO4 composite has completely decolourized the dye in 60 min of UV-Vis irradiation. k for ZnO/CuWO4 was ~2.5-times larger than that of ZnO. A 3-cycle reusability test with MO showed a small decrease in efficiency in the last cycle. TPA degradation has revealed lower efficiency for ZnO/CuWO4 in air but high efficiency in O2 and N2 atmosphere, where it reached 90% and 55% degradation rate, respectively.
Ključne besede: photocatalysis, zinc oxide, heterostructures, powders, Ag/ZnO composites, ZnO/CuWO4 composites
Objavljeno: 31.05.2017; Ogledov: 913; Prenosov: 98
Polno besedilo (4,11 MB)