T-wave alternans predicts mortality in a population undergoing a clinically indicated exercise test.

Eur Heart J. 2007 Oct;28(19):2332-7. Epub 2007 Jul 25.

Isentropic Exergy and Pressure of the Shock Wave Caused by the Explosion of a Pressure Vessel

An accidental burst of a pressure vessel is an uncontrollable and explosion-like batch process. In this study it is called an explosion. The destructive effectof a pressure vessel explosion is relative to the amount of energy released in it. However, in the field of pressure vessel safety, a mutual understanding concerning the definition of explosion energy has not yet been achieved. In this study the definition of isentropic exergy is presented. Isentropic exergy is the greatest possible destructive energy which can be obtained from a pressure vessel explosion when its state changes in an isentropic way from the initial to the final state. Finally, after the change process, the gas has similar pressure and flow velocity as the environment. Isentropic exergy differs from common exergy inthat the process is assumed to be isentropic and the final gas temperature usually differs from the ambient temperature. The explosion process is so fast that there is no time for the significant heat exchange needed for the common exergy.Therefore an explosion is better characterized by isentropic exergy. Isentropicexergy is a characteristic of a pressure vessel and it is simple to calculate. Isentropic exergy can be defined also for any thermodynamic system, such as the shock wave system developing around an exploding pressure vessel. At the beginning of the explosion process the shock wave system has the same isentropic exergyas the pressure vessel. When the system expands to the environment, its isentropic exergy decreases because of the increase of entropy in the shock wave. The shock wave system contains the pressure vessel gas and a growing amount of ambient gas. The destructive effect of the shock wave on the ambient structures decreases when its distance from the starting point increases. This arises firstly from the fact that the shock wave system is distributed to a larger space. Secondly, the increase of entropy in the shock waves reduces the amount of isentropic exergy. Equations concerning the change of isentropic exergy in shock waves are derived. By means of isentropic exergy and the known flow theories, equations illustrating the pressure of the shock wave as a function of distance are derived. Amethod is proposed as an application of the equations. The method is applicablefor all shapes of pressure vessels in general use, such as spheres, cylinders and tubes. The results of this method are compared to measurements made by various researchers and to accident reports on pressure vessel explosions. The test measurements are found to be analogous with the proposed method and the findings in the accident reports are not controversial to it.

On Short Exponential Sums Involving Fourier Coefficients of Holomorphic Cusp Forms

By an exponential sum of the Fourier coefficients of a holomorphic cusp form we mean the sum which is formed by first taking the Fourier series of the said form,then cutting the beginning and the tail away and considering the remaining sum on the real axis. For simplicity’s sake, typically the coefficients are normalized. However, this isn’t so important as the normalization can be done and removed simply by using partial summation. We improve the approximate functional equation for the exponential sums of the Fourier coefficients of the holomorphic cusp forms by giving an explicit upper bound for the error term appearing in the equation. The approximate functional equation is originally due to Jutila [9] and a crucial tool for transforming sums into shorter sums. This transformation changes the point of the real axis on which the sum is to be considered. We also improve known upper bounds for the size estimates of the exponential sums. For very short sums we do not obtain any better estimates than the very easy estimate obtained by multiplying the upper bound estimate for a Fourier coefficient (they are bounded by the divisor function as Deligne [2] showed) by the number of coefficients. This estimate is extremely rough as no possible cancellation is taken into account. However, with small sums, it is unclear whether there happens any remarkable amounts of cancellation.

“That you too were the I”: Forms of polyphonic communication in John Ashbery’s poetry

Tarkastelen tutkimuksessani amerikkalaisen John Ashberyn (1927–) runoudessa lmenevää moniäänisyyttä. Runoutta pidetään yleensä yksiäänisenä puheena, kun taas omaanin ajatellaan erityisesti Mihail Bahtinin vaikutuksesta olevan luonnostaan oniääninen kirjallisuudenlaji. Ashberyn postmoderni runous haastaa tämän äsityksen. Ashbery tunnetaan vakiintuneita runouskäsityksiä vastaan kirjoittavana avantgarde-runoilijana. Pääasiallisina tutkimuskohteinani ovat Ashberyn pitkä runoelma nimeltä ”Litany” (1979) sekä lyhyiden runojen valikoima Your Name Here (2000). Vertailukohtana tarkastelen Ashberyn yhdessä James Schuylerin kanssa kirjoittamaa romaania A Nest of Ninnies (1969). Teoreettisena pohjana on käytetty Ashberyä käsittelevän muun tutkimuksen lisäksi muun muassa jälkistrukturalistisiin teorioihin liittyviä ajatuksia pronominien vaikutuksesta siihen miten lukija muodostaa käsityksen subjektiivisesta läsnäolosta runossa. Ashbery käyttää persoonapronomineja ilman selkeitä viittaussuhteita. Viittaussuhteiden hämärtymisen ja fragmentaarisuuden vuoksi Ashberyn runoja pidetään usein vaikeina, eikä niistä ole helppo löytää yhtä selkeää aihetta. Hajanaisuus on kuitenkin motivoitua, koska juuri se mahdollistaa moniäänisyyden ja avoimen tekstin, joka voi sisältää monia merkityksiä. Kun runossa ei ole yhden puhujan hallitsevaa ääntä, lukijan rooli merkitysten muodostajana nousee keskeiseksi. ”Litany” on selkeästi metatekstuaalinen runo, jossa fiktiivinen taso sekoittuu runouden, taiteen ja kritiikin mahdollisuuksien pohdintaan. Runo hahmottelee uudenlaista, moniäänistä teorian ja runouden rajoja purkavaa kommunikaation muotoa. Toisen persoonan pronominien voidaan runossa usein ajatella puhuttelevan lukijaa. Your Name Here -kokoelmassa puolestaan toisen persoonan pronominipositiot määrittyvät usein tietyiksi henkilöhahmoiksi runojen maailmassa, ja pronominipositioiden kautta runoissa rakentuu moniäänisiä dialogeja määrittymättömien henkilöhahmojen välille. Näin lukijan huomio suunnataan ensisijaisesti kommunikaation ja arkipäivän kielenkäytön kliseiden sävyihin ja asiayhteyksiin pikemminkin kuin yksittäisten lausumien sisältöön. A Nest of Ninnies -romaani toimii näennäisestä dialogisuudestaan huolimatta ennen kaikkea yksiäänisesti, sillä romaanin yksiulotteisten henkilöhahmojen esittämiä ajatuksia hallitsee parodioimaan pyrkivä kertojanääni. Ashberyn runojen ja romaanin tarkasteleminen osoittaa, että käsitys runoudesta väistämättä yksiäänisenä ja romaanista moniäänisenä ei ole kaikilta osin ongelmaton. Moniääninen, monimerkityksinen runo voi tarjota toiselle itsenäisen aseman.

Dialogue in the crisis of representation : realism and antirealism in the context of the conversation between theologians and quantum physicists in Göttingen 1949-1961

The aim of this study is to analyse the content of the interdisciplinary conversations in Göttingen between 1949 and 1961. The task is to compare models for describing reality presented by quantum physicists and theologians. Descriptions of reality indifferent disciplines are conditioned by the development of the concept of reality in philosophy, physics and theology. Our basic problem is stated in the question: How is it possible for the intramental image to match the external object?Cartesian knowledge presupposes clear and distinct ideas in the mind prior to observation resulting in a true correspondence between the observed object and the cogitative observing subject. The Kantian synthesis between rationalism and empiricism emphasises an extended character of representation. The human mind is not a passive receiver of external information, but is actively construing intramental representations of external reality in the epistemological process. Heidegger's aim was to reach a more primordial mode of understanding reality than what is possible in the Cartesian Subject-Object distinction. In Heidegger's philosophy, ontology as being-in-the-world is prior to knowledge concerning being. Ontology can be grasped only in the totality of being (Dasein), not only as an object of reflection and perception. According to Bohr, quantum mechanics introduces an irreducible loss in representation, which classically understood is a deficiency in knowledge. The conflicting aspects (particle and wave pictures) in our comprehension of physical reality, cannot be completely accommodated into an entire and coherent model of reality. What Bohr rejects is not realism, but the classical Einsteinian version of it. By the use of complementary descriptions, Bohr tries to save a fundamentally realistic position. The fundamental question in Barthian theology is the problem of God as an object of theological discourse. Dialectics is Barth¿s way to express knowledge of God avoiding a speculative theology and a human-centred religious self-consciousness. In Barthian theology, the human capacity for knowledge, independently of revelation, is insufficient to comprehend the being of God. Our knowledge of God is real knowledge in revelation and our words are made to correspond with the divine reality in an analogy of faith. The point of the Bultmannian demythologising programme was to claim the real existence of God beyond our faculties. We cannot simply define God as a human ideal of existence or a focus of values. The theological programme of Bultmann emphasised the notion that we can talk meaningfully of God only insofar as we have existential experience of his intervention. Common to all these twentieth century philosophical, physical and theological positions, is a form of anti-Cartesianism. Consequently, in regard to their epistemology, they can be labelled antirealist. This common insight also made it possible to find a common meeting point between the different disciplines. In this study, the different standpoints from all three areas and the conversations in Göttingen are analysed in the frameworkof realism/antirealism. One of the first tasks in the Göttingen conversations was to analyse the nature of the likeness between the complementary structures inquantum physics introduced by Niels Bohr and the dialectical forms in the Barthian doctrine of God. The reaction against epistemological Cartesianism, metaphysics of substance and deterministic description of reality was the common point of departure for theologians and physicists in the Göttingen discussions. In his complementarity, Bohr anticipated the crossing of traditional epistemic boundaries and the generalisation of epistemological strategies by introducing interpretative procedures across various disciplines.

Method and arrangement for collecting wave energy

US-patentti nro: US 7,908,854 B2