993 resultados para relativistic plasmas


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A relativistic bound-state formalism is used to calculate the branching ratio Γ(V→H+γ)/Γ(V→e+e-) where H is a Higgs scalar and significant relativistic effects have been obtained compared to the nonrelativistic calculation originally due to Wilczek

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This study focuses on two philosophical issues related to the interpretation of art. Firstly, it considers the role of authorial intentions in interpretation. Secondly, the study raises the issue of relativism in interpretation through a discussion of the relativistic tendencies apparent in the views of three major figures of contemporary philosophy: Joseph Margolis, Hans-Georg Gadamer, and Richard Rorty. The major goal of the thesis is to develop a theory of interpretation supporting the role of authorial intentions in interpretation on the basis of Donald Davidson s late philosophy of language and the holistic account of interpretation that underlies different parts of his philosophy. It is my belief that an intentionalist view of interpretation built on Davidsonian elements manages to form the most convincing defense of that interpretive position against the skepticism present in the views of Margolis, Gadamer, and Rorty. The theoretical issues addressed in the thesis are illuminated by discussions of case-examples, most importantly Richard Wagner s The Valkyrie, Thomas Adés America: A Prophecy, and some symphonies by Dimitri Shostakovich. In chapter one, I present a critical discussion of Margolis robust relativism. While finding Margolis criticism of the self-refutive argument plausible, I, nevertheless, argue that the relativistic logic Margolis offers should not be favored in interpretation. The first parts of chapter two outline Davidsonian intentionalism by presenting a reading of Davidson s later work in philosophy of language and mind, and by indicating its relationship to Davidson s views of literature. Then, I shall compare Davidson s ideas with some recent modest forms of intentionalism found in analytic aesthetics, and argue that Davidsonian intentionalism is in many respects more satisfactory compared to them. Chapter three engages Gadamer s hermeneutics by defending E.D. Hirsch s criticism of Gadamer. Uncovering the shortcomings in the replies of Gadamer s followers to Hirsch s criticism serves as a basis for the defense of intentionalism in interpretation carried out in the chapter. That defense is then extended with a discussion of some recent hermeneutic readings of Davidson s views. Chapter four deals with the standing of intentionalism through Rorty s pragmatist approach to literature. By indicating the position of pragmatist notions of aesthetic experience and imagination in Davidsonian intentionalism, it is shown that an intentionalist approach need not be as impoverished with regard to the value Rorty attributes to literature as he assumes. The concluding chapter outlines some ways in which one can be a pluralist with regard to art and interpretation without falling into relativism.

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Religion without religion. The challenge of radical postmodern philosophy of religion. The aim of this study is to examine the central ideas of Mark C. Taylor, Don Cupitt, and Grace Jantzen on the subject of the philosophy of religion. The method is a qualitative, systematic analysis of the works of the aforementioned philosophers. The purpose is to present, analyze, identify, find connections, and to gain an understanding of the original texts. This thesis shows that radical postmodern religion is “religion without religion”. God is “dead” and the concept of God is seen as “writing”, an ideal, a relationship of meanings or a language. In ethics, there are no objective values or principles. People must create their own morality. Reality is each person´s concept of reality. Language is universal in that language and reality cannot be considered separately. The human subject is contingent and formed in the linguistic and social context. According to postmodern feminism, the ideas that men present as facts are often degrading to women, distort reality and support the power of men. For this reason, we should create a new kind of philosophy of religion and a new language that takes women into consideration. Finally, we will study some philosophers, who have used postmodern ideas in a more moderate manner. In this way, we will look for a balanced solution between modernism and postmodernism. This study shows that the postmodern idea of religion is very different from classical Christianity. Ethics becomes subjective, anarchistic and nihilistic. Epistemology is relativistic and the human being becomes the measure of all things. Objective reality becomes blurry. Language is seen to be game-like, and it has no relation to reality. The moral responsibility of a subject becomes problematic. Science and rationality come into question without the permanent core provided by our consciousness. Women are not in an epistemologically privileged position. The truth claims by either men or women must each be evaluated one at a time. Many postmodern ideas can successfully be made of use if used in moderate manner.

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The aim of this dissertation is to explore the academic thinking and personal epistemology of university students. More specifically, the aim is to understand and promote students’ research and academic skills as a central goal of academic studies in the research-intensive university of Helsinki. Two of the four studies examine the personal epistemology of psychology students in different study phases, and the variation in personal epistemology among final-year psychology, theology and pharmacy students. Furthermore, personal epistemology was explored as a phenomenon among the student groups. In the fourth study the individual answers of the students interviewed are investigated in more detail. The main focus is on examining students’ beliefs about the nature of knowledge and knowledge acquisition as a representation of their personal epistemology. Study I presents a model which describes the main elements and aspects of teaching and learning in pharmacy education. Firstly, the meaning of quality of teaching and learning is explored. On the basis of this information, the study concentrates on the pedagogical implications of changing pharmacy teaching to improve the quality of learning. Study II describes the results of a cross-sectional study of psychology students participating in undergraduate and master’s level psychology programmes. The students (N = 53) were interviewed concerning their beliefs about knowledge and knowing, the aim being to explore students’ responses about thinking and reasoning. The results are analysed using content analysis to create categories of personal epistemology and comparisons among the students according to the phase of their studies. Study III examines interdisciplinary differences in final-year psychology, pharmacy and theology students’ (N = 52) academic thinking and personal epistemology. The aims of study IV are to examine and compare the consistency of personal epistemology profiles among university students (N = 87) representing three academic disciplines. The individual answers are examined and rated on a scale from absolutist to evaluativist thinking. On the basis of this data, three personal epistemology profiles are identified: a) absolutist profiles; b) relativistic profiles; and c) evaluativist profiles consisting of the subgroups entitled “limited” and “sophisticated”. The results of the studies clearly demonstrate that personal epistemology varies between students in different age groups, study phases, and disciplines. Three categories, including several subcategories, emerge to describe the personal epistemology of students. Furthermore, three personal epistemology profiles can be identified from the data. The comparison between students reveals interesting differences and similarities among student groups, and developmental trends of personal epistemology.

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Gaussian-beam-type solutions to the Maxwell equations are constructed by using results from relativistic front analysis, and the propagation characteristics of these beams are analyzed. The rays of geometrical optics are shown to be the trajectories of energy flow, as given by the Poynting vector. The longitudinal components of the field vectors in the direction of the beam axis, though small, are shown to be essential for a consistent description.

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The hydromagnetic Kelvin-Helmholtz (K-H) instability problem is studied for a three-layered system analytically by arriving at the marginal instability condition. As the magnetic field directions are taken to vary in the three regions, both the angle and finite thickness effects are seen on the instability criterion. When the relative flow speed of the plasmas on the two sides of the interfaces separating the inner and the surrounding layers is U < Uc, where Uc is the critical speed, the system is stable both for symmetric and asymmetric perturbations. However, unlike the case of the interface bounded by two semiinfinite media, Uc is no longer the minimum critical speed above which the system will be unstable for all wavenumbers; another critical speed U* > Uc is introduced due to the finiteness of the system. When Uc < U < U*, the instability can set in either through the symmetric or asymmetric mode, depending on the ratio of the plasma parameters and angle between the magnetic field directions across the boundaries. The instability arises for a finite range of wavenumbers, thus giving rise to the upper and lower cut-off frequencies for the spectra of hydromagnetic surface waves generated by the K-H instability mechanism. When U > U*, both the modes are unstable for short wavelengths. The results are finally used to explain some observational features of the dependence of hydromagnetic energy spectra in the magnetosphere on the interplanetary parameters.

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By using singular surface theory and ray theory the speeds of propagation of fast and slow waves, propagating into a medium in arbitrary motion, have been obtained in relativistic magnetohydrodynamics. The differential equation governing the growth of these waves along the rays has been derived and the solution has been presented in integral form.

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The Alfvén surface waves propagating along a viscous conducting fluid-vacuum interface have been studied. It is found that besides the "ordinary" Alfvén surface waves, modified by viscosity effects, the interface can support a second mode which is the over-damped solution of the dispersion equation. The possibility of observation of a two-mode structure of Alfvén surface waves in the laboratory and in the solar coronal plasmas is discussed.

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Extending the work of earlier papers on the relativistic-front description of paraxial optics and the formulation of Fourier optics for vector waves consistent with the Maxwell equations, we generalize the Jones calculus of axial plane waves to describe the action of the most general linear optical system on paraxial Maxwell fields. Several examples are worked out, and in each case it is shown that the formalism leads to physically correct results. The importance of retaining the small components of the field vectors along the axis of the system for a consistent description is emphasized.

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Gravitaation kvanttiteorian muotoilu on ollut teoreettisten fyysikkojen tavoitteena kvanttimekaniikan synnystä lähtien. Kvanttimekaniikan soveltaminen korkean energian ilmiöihin yleisen suhteellisuusteorian viitekehyksessä johtaa aika-avaruuden koordinaattien operatiiviseen ei-kommutoivuuteen. Ei-kommutoivia aika-avaruuden geometrioita tavataan myös avointen säikeiden säieteorioiden tietyillä matalan energian rajoilla. Ei-kommutoivan aika-avaruuden gravitaatioteoria voisi olla yhteensopiva kvanttimekaniikan kanssa ja se voisi mahdollistaa erittäin lyhyiden etäisyyksien ja korkeiden energioiden prosessien ei-lokaaliksi uskotun fysiikan kuvauksen, sekä tuottaa yleisen suhteellisuusteorian kanssa yhtenevän teorian pitkillä etäisyyksillä. Tässä työssä tarkastelen gravitaatiota Poincarén symmetrian mittakenttäteoriana ja pyrin yleistämään tämän näkemyksen ei-kommutoiviin aika-avaruuksiin. Ensin esittelen Poincarén symmetrian keskeisen roolin relativistisessa fysiikassa ja sen kuinka klassinen gravitaatioteoria johdetaan Poincarén symmetrian mittakenttäteoriana kommutoivassa aika-avaruudessa. Jatkan esittelemällä ei-kommutoivan aika-avaruuden ja kvanttikenttäteorian muotoilun ei-kommutoivassa aika-avaruudessa. Mittasymmetrioiden lokaalin luonteen vuoksi tarkastelen huolellisesti mittakenttäteorioiden muotoilua ei-kommutoivassa aika-avaruudessa. Erityistä huomiota kiinnitetään näiden teorioiden vääristyneeseen Poincarén symmetriaan, joka on ei-kommutoivan aika-avaruuden omaama uudentyyppinen kvanttisymmetria. Seuraavaksi tarkastelen ei-kommutoivan gravitaatioteorian muotoilun ongelmia ja niihin kirjallisuudessa esitettyjä ratkaisuehdotuksia. Selitän kuinka kaikissa tähänastisissa lähestymistavoissa epäonnistutaan muotoilla kovarianssi yleisten koordinaattimunnosten suhteen, joka on yleisen suhteellisuusteorian kulmakivi. Lopuksi tutkin mahdollisuutta yleistää vääristynyt Poincarén symmetria lokaaliksi mittasymmetriaksi --- gravitaation ei-kommutoivan mittakenttäteorian saavuttamisen toivossa. Osoitan, että tällaista yleistystä ei voida saavuttaa vääristämällä Poincarén symmetriaa kovariantilla twist-elementillä. Näin ollen ei-kommutoivan gravitaation ja vääristyneen Poincarén symmetrian tutkimuksessa tulee jatkossa keskittyä muihin lähestymistapoihin.

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There is intense activity in the area of theoretical chemistry of gold. It is now possible to predict new molecular species, and more recently, solids by combining relativistic methodology with isoelectronic thinking. In this thesis we predict a series of solid sheet-type crystals for Group-11 cyanides, MCN (M=Cu, Ag, Au), and Group-2 and 12 carbides MC2 (M=Be-Ba, Zn-Hg). The idea of sheets is then extended to nanostrips which can be bent to nanorings. The bending energies and deformation frequencies can be systematized by treating these molecules as an elastic bodies. In these species Au atoms act as an 'intermolecular glue'. Further suggested molecular species are the new uncongested aurocarbons, and the neutral Au_nHg_m clusters. Many of the suggested species are expected to be stabilized by aurophilic interactions. We also estimate the MP2 basis-set limit of the aurophilicity for the model compounds [ClAuPH_3]_2 and [P(AuPH_3)_4]^+. Beside investigating the size of the basis-set applied, our research confirms that the 19-VE TZVP+2f level, used a decade ago, already produced 74 % of the present aurophilic attraction energy for the [ClAuPH_3]_2 dimer. Likewise we verify the preferred C4v structure for the [P(AuPH_3)_4]^+ cation at the MP2 level. We also perform the first calculation on model aurophilic systems using the SCS-MP2 method and compare the results to high-accuracy CCSD(T) ones. The recently obtained high-resolution microwave spectra on MCN molecules (M=Cu, Ag, Au) provide an excellent testing ground for quantum chemistry. MP2 or CCSD(T) calculations, correlating all 19 valence electrons of Au and including BSSE and SO corrections, are able to give bond lengths to 0.6 pm, or better. Our calculated vibrational frequencies are expected to be better than the currently available experimental estimates. Qualitative evidence for multiple Au-C bonding in triatomic AuCN is also found.

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Tension banding castration of cattle is gaining favour because it is relatively simple to perform and is promoted by retailers of the banders as a humane castration method. Two experiments were conducted, under tropical conditions using Bos indicus bulls comparing tension banding (Band) and surgical (Surgical) castration of weaner (7–10 months old) and mature (22–25 months old) bulls with and without pain management (NSAID (ketoprofen) or saline injected intramuscularly immediately prior to castration). Welfare outcomes were assessed using a range of measures; this paper reports on some physiological, morbidity and productivity-related responses to augment the behavioural responses reported in an accompanying paper. Blood samples were taken on the day of castration (day 0) at the time of restraint (0 min) and 30 min (weaners) or 40 min (mature bulls), 2 h, and 7 h; and days 1, 2, 3, 7, 14, 21 and 28 post-castration. Plasmas from day 0 were assayed for cortisol, creatine kinase, total protein and packed cell volume. Plasmas from the other samples were assayed for cortisol and haptoglobin (plus the 0 min sample). Liveweights were recorded approximately weekly to 6 weeks and at 2 and 3 months post-castration. Castration sites were checked at these same times to 2 months post-castration to score the extent of healing and presence of sepsis. Cortisol concentrations (mean ± s.e. nmol/L) were significantly (P < 0.05) higher in the Band (67 ± 4.5) compared with Surgical weaners (42 ± 4.5) at 2 h post-castration, but at 24 h post-castration were greater in the Surgical (43 ± 3.2) compared with the Band weaners (30 ± 3.2). The main effect of ketoprofen was on the cortisol concentrations of the mature Surgical bulls; concentrations were significantly reduced at 40 min (47 ± 7.2 vs. 71 ± 7.2 nmol/L for saline) and 2 h post-castration (24 ± 7.2, vs. 87 ± 7.2 nmol/L for saline). Ketoprofen, however, had no effect on the Band mature bulls, with their cortisol concentrations averaging 54 ± 5.1 nmol/L at 40 min and 92 ± 5.1 nmol/L at 2 h. Cortisol concentrations were also significantly elevated in the Band (83 ± 3.0 nmol/L) compared with Surgical mature bulls (57 ± 3.0 nmol/L) at weeks 2–4 post-castration. The timing of this elevation coincided with significantly elevated haptoglobin concentrations (mg/mL) in the Band bulls (2.97 ± 0.102 for mature bulls and 1.71 ± 0.025 for weaners, vs. 2.10 ± 0.102 and 1.45 ± 0.025 respectively for the Surgical treatment) and evidence of slow wound healing and sepsis in both the weaner (0.81 ± 0.089 not healed at week 4 for Band, 0.13 ± 0.078 for Surgical) and mature bulls (0.81 ± 0.090 at week 4 for Band, 0.38 ± 0.104 for Surgical). Overall, liveweight gains of both age groups were not affected by castration method. The findings of acute pain, chronic inflammation and possibly chronic pain in the mature bulls at least, together with poor wound healing in the Band bulls support behavioural findings reported in the accompanying paper and demonstrate that tension banding produces inferior welfare outcomes for weaner and mature bulls compared with surgical castration.

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The Pastor and the Bible: Finnish Evangelical Lutheran Pastors Relationship with the Bible Since 1970s there has been extensive discussion in Finland about questions relating to the interpretation of the Bible. The themes of this discussion have focused on the trustworthiness and authority of the Bible, and the discussion has attracted participation not only from representatives of the Evangelical Lutheran Church of Finland but also from representatives of the academic community. The discussion has resulted in extensive publication on the relation of postmodern theology to the Bible. Despite this debate and the texts that have been produced, there is little empirical data on how Evangelical Lutheran pastors with theological education view the Bible. In the present study, 22 pastors of the Evangelical Lutheran Church of Finland were interviewed about how they defined their relationship with the Bible. The interview material was analyzed by means of data-based content analysis. The analysis showed, first, that the pastors viewed the Bible as a mirror of the spiritual growth that they had experienced in the past. Second, the Bible was viewed as a source in the interpretation of matters of faith. The third theme concerned the pastors key experiences in their relationship with the authority of the Bible. The time periods that were significant in defining pastors spiritual growth and past perspective on the Bible included childhood, youth, the period of theological education, and the time spent as a pastor. In childhood, the Bible was part of the spiritual atmosphere of the home, and parents and grandparents made a crucial contribution to the child s emerging view of the Bible. In childhood, the Bible was essentially the Old Testament and its exciting stories. In youth, reading the Bible became more personal, and the teachings of Jesus began to take on a more central role. In youth, most of the interviewees had strong experiences of faith and began to view the Bible as an absolute and divine source of dogma. The period of theological studies meant a change in their relationship with the Bible and particularly, revelation of the human aspects of the Bible. These changes were associated with a deepening of belief in the Bible and also a painful crisis in questions related to the trustworthiness of the Bible. For many of the interviewees, their relationship with the Bible changed also when they started their work as pastors. When faced with a call to work as a pastor, the interviewees created a synthesis of the secure faith that they had experienced in their childhood and the more critical views with which they had become acquainted during their theological education. Pastorhood meant the beginning of public teaching of the Bible. The interviewees felt that, in this new role, they discovered again - but now in a deeper sense - the trustworthiness in the bible that they had experienced during their childhood. Based on the interviewees experiences during the periods mentioned above, five different interpretations were formed regarding how the interviewed pastors viewed their past relationship with the Bible. These interpretations were detachment from literal interpretation of the Bible (1), changes in their relationship with the Bible arising from experiences of faith (2), a slow process during which their relationship with the Bible became more human (3), overcoming hardships (4), and no change in their relationship with the Bible (5). In interpretations 1-3, the past was described as a linear development and journey towards a more coherent relationship with the Bible. Interpretations 4-5, in turn, reflected a desire to detach oneself from the perspectives of linear development and change and, instead, emphasize the immutable and process-like nature of one s relationship with the Bible. Concerning the Bible as a source in matters of faith, a conspicuous aspect of the interviews was that all pastors wanted to disconnect themselves from a fundamentalistic view of the Bible, regarding this as an intellectually dishonest relationship with the Bible. On the other hand, none of the interviewees supported a totally relativist view of the Bible. Instead, all interviewees regarded the Bible as a vital source for both them and the Evangelical Lutheran Church. Between the two poles of extremely fundamental and extremely relativistic views, four different categories of viewing the Bible emerged from the interviews: absolute truth (a), a book about the message of salvation (b), a book about holiness and generous love (c), and a source of inspiration (d). The views in categories (a) and (b) emphasized the divine nature of the Bible. According to the pastors who expressed these views, the Bible contains a clear and trustworthy message of God. The views in categories (c) and (d), in turn, emphasized the human aspects of the Bible. The pastors who expressed these views regarded the Bible as a collection of books that was born in a specific historical and cultural context and includes material characteristic to this time. Due to the time-bound nature of the Bible, each generation has to update its view of the Bible. The views in categories (c) and (d) arose from human reality. Comparisons of the views in the different categories indicated that despite their obvious differences, they also shared some common features. The views in categories (a) and (d) shared the common feature of absoluteness, which was seen in category (a) as an emphasis on dogmatism and in category (d) as an emphasis on rationalism. The views in categories (b) and (c), in turn, shared the common feature of a flexible and dynamic relationship with the Bible. The key experiences that appeared to characterize pastors relationship with the authority of the Bible were a joy that arises from self-evidence, awakening to confusion, fear of openness, falling back upon paradoxes, and new confidence. These experiences reveal the circular nature of the process that was common to all interviewees interpretation of their relationship with the Bible. That is, the interviewees experiences of their relationship with the Bible seem to go through a circular process that is activated again and again in new life events. It is like a journey from self-evidence towards critical questions and again back to new confidence. The interview material showed, hence, that relationship with the Bible are characterized by a process that involves experiences of trust, questioning and new trust. The present study brings out the multifaceted reality of pastors relationship with the Bible. The study breaks down contradictions between conservative and liberal views of the Bible by showing how representatives of these opposing poles share commonalities in their attitudes. The study points to a close association between an individual s life history and his or her relationship with the Bible, and lays the groundwork for future studies to investigate the relation between personality and view of the Bible.

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An attempt has been made to generalise a method developed earlier for the qualitative assessment of crossover frequencies (existence and behaviour) in multicomponent plasmas with one negative ion species to plasmas with any number of positive and negative ion species. It is shown that a great deal of qualitative information can be obtained regarding the crossover frequencies for any given plasma model without recourse to cumbersome numerical study. Possible applications of the study in the interpretation of frequency time spectrograms for the detection of negative ion whistlers and in the measurement of concentrations and masses of negative ions are noted.

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Heating of laser produced plasmas by an instability is investigated. For intense laser beams anomalous absorption is found. A comparison is made with the experiment.