Lightning-Induced Voltages on Overhead Lines-Application of the Extended Rusck Model

Lightning-induced overvoltages have a considerable impact on the power quality of overhead distribution and telecommunications systems, and various models have been developed for the computation of the electromagnetic transients caused by indirect strokes. The most adequate has been shown to be the one proposed by Agrawal et al.; the Rusck model can be visualized as a particular case, as both models are equivalent when the lightning channel is perpendicular to the ground plane. In this paper, an extension of the Rusck model that enables the calculation of lightning-induced transients considering flashes to nearby elevated structures and realistic line configurations is tested against data obtained from both natural lightning and scale model experiments. The latter, performed under controlled conditions, can be used also to verify the validity of other coupling models and relevant codes. The so-called Extended Rusck Model, which is shown to be sufficiently accurate, is applied to the analysis of lightning-induced voltages on lines with a shield wire and/or surge arresters. The investigation conducted indicates that the ratio between the peak values of the voltages induced by typical first and subsequent strokes can be either greater or smaller than the unity, depending on the line configuration.

Accurate prediction of the Si/SiO(2) interface band offset using the self-consistent ab initio DFT/LDA-1/2 method

We use the density functional theory/local-density approximation (DFT/LDA)-1/2 method [L. G. Ferreira , Phys. Rev. B 78, 125116 (2008)], which attempts to fix the electron self-energy deficiency of DFT/LDA by half-ionizing the whole Bloch band of the crystal, to calculate the band offsets of two Si/SiO(2) interface models. Our results are similar to those obtained with a ""state-of-the-art"" GW approach [R. Shaltaf , Phys. Rev. Lett. 100, 186401 (2008)], with the advantage of being as computationally inexpensive as the usual DFT/LDA. Our band gap and band offset predictions are in excellent agreement with experiments.

Loviisan ydinvoimalaitoksen todennäköisyyspohjaisen riskianalyysin tason 2 epävarmuustarkastelut

Diplomityössä tarkastellaan Loviisan ydinvoimalaitoksen todennäköisyyspohjaisen riskianalyysin tason 2 epävarmuuksia. Tason 2 riskitutkimuksissa tutkitaan ydinvoimalaitosonnettomuuksia, joiden seurauksena osa reaktorin radioaktiivisista aineista vapautuu ympäristöön. Näiden tutkimuksien päätulos on suuren päästön vuotuinen taajuus ja se on pääosin todelliseen laitoshistoriaan perustuva tilastollinen odotusarvo. Tämän odotusarvon uskottavuutta voidaan parantaa huomioimalla merkittävimmät laskentaan liittyvät epävarmuudet. Epävarmuuksia laskentaan aiheutuu muiden muassa vakavan reaktorionnettomuuden ilmiöistä, turvallisuusjärjestelmien laitteista, inhimillisistä toiminnoista sekä luotettavuusmallin määrittelemättömistä osista. Diplomityössä kuvataan, kuinka epävarmuustarkastelut integroidaan osaksi Loviisan ydinvoimalaitoksen todennäköisyyspohjaisia riskianalyysejä. Tämä toteutetaan diplomityössä kehitetyillä apuohjelmilla PRALA:lla ja PRATU:lla, joiden avulla voidaan lisätä laitoshistorian perusteella muodostetut epävarmuusparametrit osaksi riskianalyysien luotettavuusdataa. Lisäksi diplomityössä on laskettu laskentaesimerkkinä Loviisan ydinvoimalaitoksen suuren päästön vuotuisen taajuuden vaihtelua kuvaava luottamusväli. Tämä laskentaesimerkki pohjautuu pääosin konservatiivisiin epävarmuusarvioihin, ei todellisiin tilastollisiin epävarmuuksiin. Laskentaesimerkin tulosten perusteella Loviisan suuren päästön taajuudella on laaja vaihteluväli; virhekertoimeksi saatiin 8,4 nykyisillä epävarmuusparametreilla. Suuren päästön taajuuden luottamusväliä voidaan kuitenkin tulevaisuudessa supistaa, kun hyödynnetään todelliseen laitoshistoriaan perustuvia epävarmuusparametreja.

The integrated WRF/urban modelling system: development, evaluation, and applications to urban environmental problems

To bridge the gaps between traditional mesoscale modelling and microscale modelling, the National Center for Atmospheric Research, in collaboration with other agencies and research groups, has developed an integrated urban modelling system coupled to the weather research and forecasting (WRF) model as a community tool to address urban environmental issues. The core of this WRF/urban modelling system consists of the following: (1) three methods with different degrees of freedom to parameterize urban surface processes, ranging from a simple bulk parameterization to a sophisticated multi-layer urban canopy model with an indoor–outdoor exchange sub-model that directly interacts with the atmospheric boundary layer, (2) coupling to fine-scale computational fluid dynamic Reynolds-averaged Navier–Stokes and Large-Eddy simulation models for transport and dispersion (T&D) applications, (3) procedures to incorporate high-resolution urban land use, building morphology, and anthropogenic heating data using the National Urban Database and Access Portal Tool (NUDAPT), and (4) an urbanized high-resolution land data assimilation system. This paper provides an overview of this modelling system; addresses the daunting challenges of initializing the coupled WRF/urban model and of specifying the potentially vast number of parameters required to execute the WRF/urban model; explores the model sensitivity to these urban parameters; and evaluates the ability of WRF/urban to capture urban heat islands, complex boundary-layer structures aloft, and urban plume T&D for several major metropolitan regions. Recent applications of this modelling system illustrate its promising utility, as a regional climate-modelling tool, to investigate impacts of future urbanization on regional meteorological conditions and on air quality under future climate change scenarios. Copyright © 2010 Royal Meteorological Society

Soliton spectrum of integrable models with local symmetries

The soliton spectrum (massive and massless) of a family of integrable models with local U(1) and U(1) ⊗U(1) symmetries is studied. These models represent relevant integrable deformations of SL(2,ℝ) ⊗U(1) n-1-WZW and SL(2,ℝ) ⊗ SL(2,ℝ) ⊗U(1) n-2-WZW models. Their massless solitons appear as specific topological solutions of the U(1)(or U(1) ⊗ U(1)-) CFTs. The nonconformal analog of the GKO-coset formula is derived and used in the construction of the composite massive solitons of the ungauged integrable models. © SISSA/ISAS 2002.

J/Ψ in nuclear matter

We report on recent estimates of the J/Ψ mass shift in infinite nuclear matter and finite nuclei arising from in-medium D and D* meson loops. The density dependence of the J/Ψ mass shift is evaluated employing medium-modified D and D* meson masses derived within the quark-meson coupling model. Using a local density approximation, J/Ψ-nuclear bound state energies are calculated for a range of nuclei. We predict that J/Ψ-nuclear bound states should be observed with a clear signal in experiments, provided the J/Ψ meson is produced in recoilless kinematics. © Published under licence by IOP Publishing Ltd.

Internalized somatostatin receptor subtype 2 in neuroendocrine tumors of octreotide-treated patients

Somatostatin receptor subtype 2 (sst(2)) is widely expressed in neuroendocrine tumors and can be visualized immunohistochemically at the cell membrane for diagnostic purposes. Recently, it has been demonstrated in animal sst(2) tumor models in vivo that somatostatin analog treatment was able to induce a complete internalization of the tumor sst(2).

Efforts and Models of Education for Parents: the Danish Approach

The report examines the relationship between day care institutions, schools and so called “parents unfamiliar to education” as well as the relationship between the institutions. With in Danish public and professional discourse concepts like parents unfamiliar to education are usually referring to environments, parents or families with either no or just very restricted experience of education except for the basic school (folkeskole). The “grand old man” of Danish educational research, Prof. Em. Erik Jørgen Hansen, defines the concept as follows: Parents who are distant from or not familiar with education, are parents without tradition of education and by that fact they are not able to contribute constructively in order to back up their own children during their education. Many teachers and pedagogues are not used to that term; they rather prefer concepts like “socially exposed” or “socially disadvantaged” parents or social classes or strata. The report does not only focus on parents who are not capable to support the school achievements of their children, since a low level of education is usually connected with social disadvantage. Such parents are often not capable of understanding and meeting the demands from side of the school when sending their children to school. They lack the competencies or the necessary competence of action. For the moment being much attention is done from side of the Ministries of Education and Social Affairs (recently renamed Ministry of Welfare) in order to create equal possibilities for all children. Many kinds of expertise (directions, counsels, researchers, etc.) have been more than eager to promote recommendations aiming at achieving the ambitious goal: 2015 95% of all young people should complement a full education (classes 10.-12.). Research results are pointing out the importance of increased participation of parents. In other word the agenda is set for ‘parents’ education’. It seems necessary to underline that Danish welfare policy has been changing rather radical. The classic model was an understanding of welfare as social assurance and/or as social distribution – based on social solidarity. The modern model looks like welfare as social service and/or social investment. This means that citizens are changing role – from user and/or citizen to consumer and/or investor. The Danish state is in correspondence with decisions taken by the government investing in a national future shaped by global competition. The new models of welfare – “service” and “investment” – imply severe changes in hitherto known concepts of family life, relationship between parents and children etc. As an example the investment model points at a new implementation of the relationship between social rights and the rights of freedom. The service model has demonstrated that weakness that the access to qualified services in the field of health or education is becoming more and more dependent of the private purchasing power. The weakness of the investment model is that it represents a sort of “The Winner takes it all” – since a political majority is enabled to make agendas in societal fields former protected by the tripartite power and the rights of freedom of the citizens. The outcome of the Danish development seems to be an establishment of a political governed public service industry which on one side are capable of competing on market conditions and on the other are able being governed by contracts. This represents a new form of close linking of politics, economy and professional work. Attempts of controlling education, pedagogy and thereby the population are not a recent invention. In European history we could easily point at several such experiments. The real news is the linking between political priorities and exercise of public activities by economic incentives. By defining visible goals for the public servants, by introducing measurement of achievements and effects, and by implementing a new wage policy depending on achievements and/or effects a new system of accountability is manufactured. The consequences are already perceptible. The government decides to do some special interventions concerning parents, children or youngsters, the public servants on municipality level are instructed to carry out their services by following a manual, and the parents are no longer protected by privacy. Protection of privacy and minority is no longer a valuable argumentation to prevent further interventions in people’s life (health, food, school, etc.). The citizens are becoming objects of investment, also implying that people are investing in their own health, education, and family. This means that investments in changes of life style and development of competences go hand in hand. The below mentioned programmes are conditioned by this shift.

Modern mathematical methods and models; a book of experimental text materials.

v. 1. Multicomponent methods.--v. 2. Mathematical models.

The development of retinotectal maps: A review of models based on molecular gradients

Information about the world is often represented in the brain in the form of topographic maps. A paradigm example is the topographic representation of the visual world in the optic tectum/superior colliculus. This map initially forms during neural development using activity-independent molecular cues, most notably some type of chemospecific matching between molecular gradients in the retina and corresponding gradients in the tectum/superior colliculus. Exactly how this process might work has been studied both experimentally and theoretically for several decades. This review discusses the experimental data briefly, and then in more detail the theoretical models proposed. The principal conclusions are that (1) theoretical models have helped clarify several important ideas in the field, (2) earlier models were often more sophisticated than more recent models, and (3) substantial revisions to current modelling approaches are probably required to account for more than isolated subsets of the experimental data.

Moduli Space of (0,2) Conformal Field Theories

In this thesis we study aspects of (0,2) superconformal field theories (SCFTs), which are suitable for compactification of the heterotic string. In the first part, we study a class of (2,2) SCFTs obtained by fibering a Landau-Ginzburg (LG) orbifold CFT over a compact K\"ahler base manifold. While such models are naturally obtained as phases in a gauged linear sigma model (GLSM), our construction is independent of such an embedding. We discuss the general properties of such theories and present a technique to study the massless spectrum of the associated heterotic compactification. We test the validity of our method by applying it to hybrid phases of GLSMs and comparing spectra among the phases. In the second part, we turn to the study of the role of accidental symmetries in two-dimensional (0,2) SCFTs obtained by RG flow from (0,2) LG theories. These accidental symmetries are ubiquitous, and, unlike in the case of (2,2) theories, their identification is key to correctly identifying the IR fixed point and its properties. We develop a number of tools that help to identify such accidental symmetries in the context of (0,2) LG models and provide a conjecture for a toric structure of the SCFT moduli space in a large class of models. In the final part, we study the stability of heterotic compactifications described by (0,2) GLSMs with respect to worldsheet instanton corrections to the space-time superpotential following the work of Beasley and Witten. We show that generic models elude the vanishing theorem proved there, and may not determine supersymmetric heterotic vacua. We then construct a subclass of GLSMs for which a vanishing theorem holds.

Development of 3D Cancer Cell Models to Test Metabolic Interventions as an Anticancer Strategy

In recent years, it has become evident that the role of mitochondria in the metabolic rewiring is essential for cancer development and progression. The metabolic profile during tumorigenesis has been performed mainly in traditional 2D cell models, including cell lines of various lineages and phenotypes. Although useful in many ways, their relevance can be often debatable, as they lack the interactions between different cells of the tumour microenvironment and/or interaction with the extracellular matrix 1,2. Improved models are now being developed using 3D cell culture technology, contributing with increased physiological relevance 3,4. In this work, we improved a method for the generation of 3D models from healthy and tumour colon tissue, based on organoid technology, and performed their molecular and biochemical characterization and validation. Further, in-plate cryopreservation was applied to these models, and optimal results were obtained in terms of cell viability and functionality of the cryopreserved models. We also cryopreserved colon fibroblasts with the aim to introduce them in a co-culture cryopreserved model with organoids. This technology allows the conversion of cell models into “plug and play” formats. Therefore, cryopreservation in-plate facilitates the accessibility of specialized cell models to cell-based research and application, in cases where otherwise such specialized models would be out of reach. Finally, we briefly explored the field of bioprinting, by testing a new matrix to support the growth of colon tumour organoids, which revealed promising preliminary results. To facilitate the reader, we organized this thesis into chapters, divided by the main points of work which include development, characterization and validation of the model, commercial output, and associated applications. Each chapter has a brief introduction, followed by results and discussion and a final conclusion. The thesis has also a general discussion and conclusion section in the end, which covers the main results obtained during this work.

Protective Effect of RC-3095, an Antagonist of the Gastrin-Releasing Peptide Receptor, in Experimental Arthritis

Objective. To evaluate the antiinflammatory effects of RC-3095 in 2 experimental models of arthritis, collagen-induced arthritis (CIA) and antigen-induced arthritis (AIA), and to determine the mechanisms of action involved. Methods. RC-3095 was administered daily to mice with CIA and mice with AIA, after induction of disease with methylated bovine serum albumin. Disease incidence and severity were assessed using a clinical index and evaluation of histologic features, respectively. In mice with CIA, gastrin-releasing peptide receptor (GRPR) was detected by immunohistochemical analysis, while in mice with AIA, migration of neutrophils, presence of glycosaminoglycans, and lymphocyte proliferation, determined using the MTT assay, were assessed. Expression of cytokines interleukin-17 (IL-17), IL-1 beta, and tumor necrosis factor alpha (TNF alpha) was evaluated in all mouse knees using enzyme-linked immunosorbent assay. Treg cell production was assessed by flow cytometry in the joints of mice with AIA. Results. In mice with AIA, administration of RC-3095 reduced neutrophil migration, mechanical hypernociception, and proteoglycan loss. These findings were associated with inhibition of the levels of all 3 proinflammatory cytokines, decreased lymphocyte proliferation, and increased Treg cell numbers. In the CIA model, treatment with RC-3095 led to a significant reduction in arthritis clinical scores and the severity of disease determined histologically. Synovial inflammation, synovial hyperplasia, pannus formation, and extensive erosive changes were all dramatically reduced in the arthritic mice treated with RC-3095. Furthermore, arthritic mice treated with RC-3095 showed a significant reduction in the concentrations of IL-17, IL-1 beta, and TNF alpha, and showed a diminished expression of GRPR. Conclusion. These findings suggest that the GRP pathway has a significant role in chronic arthritis, and its inhibition can be explored as a possible therapeutic strategy in rheumatoid arthritis.

Glucose induced IEG expression in the thiamin-deficient rat brain

Glucose loading of rats made thiamin deficient by dietary deprivation of thiamin and the administration of pyrithiamin (40 mug/100 g, i.p.) precipitates an acute neuropathy, a model of Wernicke's encephalopathy in man (Zimitat and Nixon, Metab. Brain Dis. 1999;14:1-20). Immunohistochemical detection of Fos proteins was used as a marker to identify neuronal populations in the thiamin-deficient rat brain affected by glucose loading. As thiamin deficiency progressed, the extent and intensity of Fos-Like immunoreactivity (FLI) in brain structures typically affected by thiamin deficiency (the thalamus, mammillary bodies, inferior colliculus, vestibular nucleus and inferior olives) were markedly increased when compared to thiamin-replete controls. Glucose loading for 1-3 days further increased the intensity of FLI in these same regions, consistent with a dependence of Fos expression on carbohydrate metabolism as well as on thiamin deficiency. The timed acute changes that follow a bolus glucose load administered to thiamin-deficient animals may provide a sequential account of events in the pathogenesis of brain damage in this model of Wernicke's encephalopathy. (C) 2001 Elsevier Science B.V. All rights reserved.

Determination of regional flow by use of intravascular PET tracers: Microvascular theory and experimental validation for pig livers

Today, the standard approach for the kinetic analysis of dynamic PET studies is compartment models, in which the tracer and its metabolites are confined to a few well-mixed compartments. We examine whether the standard model is suitable for modern PET data or whether theories including more physiologic realism can advance the interpretation of dynamic PET data. A more detailed microvascular theory is developed for intravascular tracers in single-capillary and multiple-capillary systems. The microvascular models, which account for concentration gradients in capillaries, are validated and compared with the standard model in a pig liver study. Methods: Eight pigs underwent a 5-min dynamic PET study after O-15-carbon monoxide inhalation. Throughout each experiment, hepatic arterial blood and portal venous blood were sampled, and flow was measured with transit-time flow meters. The hepatic dual-inlet concentration was calculated as the flow-weighted inlet concentration. Dynamic PET data were analyzed with a traditional single-compartment model and 2 microvascular models. Results: Microvascular models provided a better fit of the tissue activity of an intravascular tracer than did the compartment model. In particular, the early dynamic phase after a tracer bolus injection was much improved. The regional hepatic blood flow estimates provided by the microvascular models (1.3 +/- 0.3 mL min(-1) mL(-1) for the single-capillary model and 1.14 +/- 0.14 min(-1) mL(-1) for the multiple-capillary model) (mean +/- SEM mL of blood min(-1) mL of liver tissue(-1)) were in agreement with the total blood flow measured by flow meters and normalized to liver weight (1.03 +/- 0.12 mL min(-1) mL(-1)). Conclusion: Compared with the standard compartment model, the 2 microvascular models provide a superior description of tissue activity after an intravascular tracer bolus injection. The microvascular models include only parameters with a clear-cut physiologic interpretation and are applicable to capillary beds in any organ. In this study, the microvascular models were validated for the liver and provided quantitative regional flow estimates in agreement with flow measurements.