555 resultados para horne-zeilinger entanglement


Relevância:

10.00% 10.00%

Publicador:

Resumo:

Résumé :Introduction : La mitoxantrone est un anthracénédione cytostatique aux ef¬fets immunosuppresseurs et -modulateurs qui est administré entre autre dans les évolutions graves de la sclérose en plaques (SEP). Peu d'études concernant l'efficacité et la tolérance de la mitoxantrone ont été publiées. Un travail de re¬cherche statistique s'imposait en raison du nombre de patients souffrant de SEP traités par ce médicament dans le service de neurologie de l'hôpital cantonal d'Aarau.Méthode : Au total, 66 patients souffrant de SEP ont été traités par la mi¬toxantrone dans la période 07/2000-06/2007. 48 d'entre eux avaient reçu préa¬lablement une autre substance modifiant l'évolution de la maladie (« prétrai¬tement » : interféron bêta-la/b, glatirameracétate, azathioprine). Dans cette étude rétrospective, nous avons comparé l'effet de la mitoxantrone par rapport au prétraitement mentionné ci-dessus. Les paramètres appliqués concernaient l'évolution de l'expanded disability status scale (EDSS) et le nombre annuel de poussées pendant la durée du traitement. Une influence du type de SEP, de l'âge au début du traitement par la mitoxantrone, du sexe, de la durée de la théra¬pie et de la maladie ainsi que de la dose cumulative de la mitoxantrone a été recherchée. Nous avons également discuté des éventuels effets indésirables surve¬nus. Nous n'avons pas différencié les substances du prétraitement, étant donné qu'elles avaient été appliquées dans des combinaisons multiples. L'évaluation sta¬tistique a été effectuée en respectant les indications du test de Mann-Whitney ainsi que du Wilcoxon signed-rank test.Résultats : En moyenne, l'EDSS s'est stabilisée (-0,05/année chez tous les 66 patients) tandis que la maladie avait progressé de 0,32/année sous le pré¬traitement (la différence est significative avec p=0,0004 au Wilcoxon signed- rank test bilatéral). Sous le prétraitement, les patients avaient subi en moyenne 1,72 poussées par année, sous la mitoxantrone 0,26 (différence significative avec p<0,0001). La thérapie a dû être arrêtée à cause d'effets indésirables chez quatre patients sous la mitoxantrone (deux avec une granulocytopénie, deux avec une diminution de la fraction d'éjection cardiaque).Discussion : La mitoxantrone s'est avéré une substance particulièrement ef¬ficace même dans les situations dans lesquelles le décours de la maladie n'a pas pu être influencé par d'autres médicaments. Ses effets indésirables doivent être pondérés par rapport à la progression de la maladie et aux effets indési¬rables des autres substances. Les schémas d'application varient beaucoup dans la littérature et doivent être mieux définis.Zusammenfassung :Einleitung: Mitoxantron ist ein zytostatisches Anthracenedion mit immunsup- pressiven und -modulatorischen Eigenschaften, das unter anderem bei schwe¬ren Verläufen der Multiplen Sklerose eingesetzt wird. Bisher befassten sich nur wenige randomisierte und plazebokontrollierte Studien mit Wirksamkeit und Tolerabilität des Medikamentes.Methoden: 66 MS-Patienten der neurologischen Klinik des Kantonsspitals Aar- au wurden zwischen Juli 2000 und Juni 2007 mit Mitoxantron behandelt. 48 davon erhielten zuvor eine MS-spezifische Behandlung mit Interferon ß-1 a oder b, Glatirameracetat oder Azathioprin. Anhand der Veränderung der Expanded Disability Status Scale (EDSS) und der jährlichen Schubrate und mit Hilfe von MRI-Aufnahmen zeichneten wir retrospektiv die Wirksamkeit der Behandlung nach und stellten sie in Beziehung zu einer eventuell erfolgten Vorbehandlung. Des weiteren wurde die Effektivität in Verhältnis zu den Faktoren Verlaufsform, Alter bei Behandlungsbeginn, Behandlungszeit sowie weiteren Parametern ge¬bracht. Wir verglichen die Wirkung von Mitoxantron bei den noch laufenden Behandlungen mit der bei den bereits abgeschlossenen und wir diskutierten die Veränderung von MRI-Aufnahmen des ZNS unter der Therapie mit Mitoxan¬tron. Nebenwirkungen wurden erwähnt.Resultate: Im Durchschnitt wurde der EDSS-Wert stabilisiert (-0, 05/Jahr bei allen 66 Patienten), während die Krankheit unter der verlaufsmodifizierenden Vorbehandlung um durchschnittlich 0,32/Jahr fortschritt (Unterschied signifi¬kant mit p=0,0004 im zweiseitigen Wilcoxon signed-rank test). Die Schubrate betrug 0,26 unter Mitoxantron gegenüber 1,72/Jahr unter Vorbehandlung (Un¬terschied signifikant mit p<0,0001). Bei vier Patienten musste die Therapie auf¬grund von Nebenwirkungen abgebrochen werden (zweimal Granulozytopenie, zweimal verminderte kardiale Auswurffraktion).Diskussion: Mitoxantron ist offensichtlich selbst dann eine äusserst effektive verlaufsmodifizierende Substanz, wenn die Krankheit durch andere Medikamen¬te nicht zu beeinflussen ist. Die Risiken des Medikamentes müssen gegen das Krankheitsfortschreiten und die Nachteile anderer verlaufsmodifizierender Sub¬stanzen abgewogen werden. Die Anwendungsalgorithmen für Mitoxantron vari¬ieren in der Literatur sehr und müssen besser definiert werden.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

High-energy charged particles in the van Allen radiation belts and in solar energetic particle events can damage satellites on orbit leading to malfunctions and loss of satellite service. Here we describe some recent results from the SPACECAST project on modelling and forecasting the radiation belts, and modelling solar energetic particle events. We describe the SPACECAST forecasting system that uses physical models that include wave-particle interactions to forecast the electron radiation belts up to 3 h ahead. We show that the forecasts were able to reproduce the >2 MeV electron flux at GOES 13 during the moderate storm of 7-8 October 2012, and the period following a fast solar wind stream on 25-26 October 2012 to within a factor of 5 or so. At lower energies of 10- a few 100 keV we show that the electron flux at geostationary orbit depends sensitively on the high-energy tail of the source distribution near 10 RE on the nightside of the Earth, and that the source is best represented by a kappa distribution. We present a new model of whistler mode chorus determined from multiple satellite measurements which shows that the effects of wave-particle interactions beyond geostationary orbit are likely to be very significant. We also present radial diffusion coefficients calculated from satellite data at geostationary orbit which vary with Kp by over four orders of magnitude. We describe a new automated method to determine the position at the shock that is magnetically connected to the Earth for modelling solar energetic particle events and which takes into account entropy, and predict the form of the mean free path in the foreshock, and particle injection efficiency at the shock from analytical theory which can be tested in simulations.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

We show that in the limit of a large number of dimensions a wide class of nonextremal neutral black holes has a universal near-horizon limit. The limiting geometry is the two-dimensional black hole of string theory with a two-dimensional target space. Its conformal symmetry explains the properties of massless scalars found recently in the large-D limit. For black branes with string charges, the near-horizon geometry is that of the three-dimensional black strings of Horne and Horowitz. The analogies between the α′ expansion in string theory and the large-D expansion in gravity suggest a possible effective string description of the large-D limit of black holes. We comment on applications to several subjects, in particular to the problem of critical collapse.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

High-energy charged particles in the van Allen radiation belts and in solar energetic particle events can damage satellites on orbit leading to malfunctions and loss of satellite service. Here we describe some recent results from the SPACECAST project on modelling and forecasting the radiation belts, and modelling solar energetic particle events. We describe the SPACECAST forecasting system that uses physical models that include wave-particle interactions to forecast the electron radiation belts up to 3 h ahead. We show that the forecasts were able to reproduce the >2 MeV electron flux at GOES 13 during the moderate storm of 7-8 October 2012, and the period following a fast solar wind stream on 25-26 October 2012 to within a factor of 5 or so. At lower energies of 10- a few 100 keV we show that the electron flux at geostationary orbit depends sensitively on the high-energy tail of the source distribution near 10 RE on the nightside of the Earth, and that the source is best represented by a kappa distribution. We present a new model of whistler mode chorus determined from multiple satellite measurements which shows that the effects of wave-particle interactions beyond geostationary orbit are likely to be very significant. We also present radial diffusion coefficients calculated from satellite data at geostationary orbit which vary with Kp by over four orders of magnitude. We describe a new automated method to determine the position at the shock that is magnetically connected to the Earth for modelling solar energetic particle events and which takes into account entropy, and predict the form of the mean free path in the foreshock, and particle injection efficiency at the shock from analytical theory which can be tested in simulations.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

BACKGROUND: Therapeutic hypothermia following hypoxic ischaemic encephalopathy in term infants was introduced into Switzerland in 2005. Initial documentation of perinatal and resuscitation details was poor and neuromonitoring insufficient. In 2011, a National Asphyxia and Cooling Register was introduced. AIMS: To compare management of cooled infants before and after introduction of the register concerning documentation, neuromonitoring, cooling methods and evaluation of temperature variability between cooling methods. STUDY DESIGN: Data of cooled infants before the register was in place (first time period: 2005-2010) and afterwards (second time period: 2011-2012) was collected with a case report form. RESULTS: 150 infants were cooled during the first time period and 97 during the second time period. Most infants were cooled passively or passively with gel packs during both time periods (82% in 2005-2010 vs 70% in 2011-2012), however more infants were cooled actively during the second time period (18% versus 30%). Overall there was a significant reduction in temperature variability (p < 0.001) comparing the two time periods. A significantly higher proportion of temperature measurements within target temperature range (72% versus 77%, p < 0.001), fewer temperature measurements above (24% versus 7%, p < 0.001) and more temperatures below target range (4% versus 16%, p < 0.001) were recorded during the second time period. Neuromonitoring improved after introduction of the cooling register. CONCLUSION: Management of infants with HIE improved since introducing the register. Temperature variability was reduced, more temperature measurements in the target range and fewer temperature measurements above target range were observed. Neuromonitoring has improved, however imaging should be performed more often.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Due to the helical structure of DNA the process of DNA replication is topologically complex. Freshly replicated DNA molecules are catenated with each other and are frequently knotted. For proper functioning of DNA it is necessary to remove all of these entanglements. This is done by DNA topoisomerases that pass DNA segments through each other. However, it has been a riddle how DNA topoisomerases select the sites of their action. In highly crowded DNA in living cells random passages between contacting segments would only increase the extent of entanglement. Using molecular dynamics simulations we observed that in actively supercoiled DNA molecules the entanglements resulting from DNA knotting or catenation spontaneously approach sites of nicks and gaps in the DNA. Type I topoisomerases, that preferentially act at sites of nick and gaps, are thus naturally provided with DNA-DNA juxtapositions where a passage results in an error-free DNA unknotting or DNA decatenation.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The objective of this thesis was to identify the effects of different factors on the tension and tension relaxation of wet paper web after high-speed straining. The study was motivated by the plausible connection between wet web mechanical properties and wet web runnability on paper machines shown by previous studies. The mechanical properties of wet paper were examined using a fast tensile test rig with a strain rate of 1000%/s. Most of the tests were carried out with laboratory handsheets, but samples from a pilot paper machine were also used. The tension relaxation of paper was evaluated as the tension remaining after 0.475 s of relaxation (residual tension). The tensile and relaxation properties of wet webs were found to be strongly dependent on the quality and amount of fines. With low fines content, the tensile strength and residual tension of wet paper was mainly determined by the mechanical interactions between fibres at their contact points. As the fines strengthen the mechanical interaction in the network, the fibre properties also become important. Fibre deformations caused by the mechanical treatment of pulp were shown to reduce the mechanical properties of both dry and wet paper. However, the effect was significantly higher for wet paper. An increase of filler content from 10% to 25% greatly reduced the tensile strength of dry paper, but did not significantly impair wet web tensile strength or residual tension. Increased filler content in wet web was shown to increase the dryness of the wet web after the press section, which partly compensates for the reduction of fibrous material in the web. It is also presumable that fillers increase entanglement friction between fibres, which is beneficial for wet web strength. Different contaminants present in white water during sheet formation resulted in lowered surface tension and increased dryness after wet pressing. The addition of different contaminants reduced the tensile strength of the dry paper. The reduction of dry paper tensile strength could not be explained by the reduced surface tension, but rather on the tendency of different contaminants to interfere with the inter-fibre bonding. Additionally, wet web strength was not affected by the changes in the surface tension of white water or possible changes in the hydrophilicity of fibres caused by the addition of different contaminants. The spraying of different polymers on wet paper before wet pressing had a significant effect on both dry and wet web tensile strength, whereas wet web elastic modulus and residual tension were basically not affected. We suggest that the increase of dry and wet paper strength could be affected by the molecular level interactions between these chemicals and fibres. The most significant increases in dry and wet paper strength were achieved with a dual application of anionic and cationic polymers. Furthermore, selectively adding papermaking chemicals to different fibre fractions (as opposed to adding chemicals to the whole pulp) improved the wet web mechanical properties and the drainage of the pulp suspension.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

In this Thesis I discuss the exact dynamics of simple non-Markovian systems. I focus on fundamental questions at the core of non-Markovian theory and investigate the dynamics of quantum correlations under non-Markovian decoherence. In the first context I present the connection between two different non-Markovian approaches, and compare two distinct definitions of non-Markovianity. The general aim is to characterize in exemplary cases which part of the environment is responsible for the feedback of information typical of non- Markovian dynamics. I also show how such a feedback of information is not always described by certain types of master equations commonly used to tackle non-Markovian dynamics. In the second context I characterize the dynamics of two qubits in a common non-Markovian reservoir, and introduce a new dynamical effect in a wellknown model, i.e., two qubits under depolarizing channels. In the first model the exact solution of the dynamics is found, and the entanglement behavior is extensively studied. The non-Markovianity of the reservoir and reservoirmediated-interaction between the qubits cause non-trivial dynamical features. The dynamical interplay between different types of correlations is also investigated. In the second model the study of quantum and classical correlations demonstrates the existence of a new effect: the sudden transition between classical and quantum decoherence. This phenomenon involves the complete preservation of the initial quantum correlations for long intervals of time of the order of the relaxation time of the system.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

In this Thesis the interaction of an electromagnetic field and matter is studied from various aspects in the general framework of cold atoms. Our subjects cover a wide spectrum of phenomena ranging from semiclassical few-level models to fully quantum mechanical interaction with structured reservoirs leading to non-Markovian open quantum system dynamics. Within closed quantum systems, we propose a selective method to manipulate the motional state of atoms in a time-dependent double-well potential and interpret the method in terms of adiabatic processes. Also, we derive a simple wave-packet model, based on distributions of generalized eigenstates, explaining the finite visibility of interference in overlapping continuous-wave atom lasers. In the context of open quantum systems, we develop an unraveling of non-Markovian dynamics in terms of piecewise deterministic quantum jump processes confined in the Hilbert space of the reduced system - the non-Markovian quantum jump method. As examples, we apply it for simple 2- and 3-level systems interacting with a structured reservoir. Also, in the context of ion-cavity QED we study the entanglement generation based on collective Dicke modes in experimentally realistic conditions including photonic losses and an atomic spontaneous decay.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Kirjallisuusarvostelu

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The present manuscript represents the completion of a research path carried forward during my doctoral studies in the University of Turku. It contains information regarding my scientific contribution to the field of open quantum systems, accomplished in collaboration with other scientists. The main subject investigated in the thesis is the non-Markovian dynamics of open quantum systems with focus on continuous variable quantum channels, e.g. quantum Brownian motion models. Non-Markovianity is here interpreted as a manifestation of the existence of a flow of information exchanged by the system and environment during the dynamical evolution. While in Markovian systems the flow is unidirectional, i.e. from the system to the environment, in non-Markovian systems there are time windows in which the flow is reversed and the quantum state of the system may regain coherence and correlations previously lost. Signatures of a non-Markovian behavior have been studied in connection with the dynamics of quantum correlations like entanglement or quantum discord. Moreover, in the attempt to recognisee non-Markovianity as a resource for quantum technologies, it is proposed, for the first time, to consider its effects in practical quantum key distribution protocols. It has been proven that security of coherent state protocols can be enhanced using non-Markovian properties of the transmission channels. The thesis is divided in two parts: in the first part I introduce the reader to the world of continuous variable open quantum systems and non-Markovian dynamics. The second part instead consists of a collection of five publications inherent to the topic.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Äänitetty radiosta.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Pro gradu -tutkielmani käsittelee sukupuolen ja seksuaalisuuden keskinäisiä intraaktiivisia vuorovaikutussuhteita elettyjen, ei-heteroseksuaalisten transsukupuolisten ruumiiden kokemuksissa. Tutkielmani haastaa sukupuolen ja seksuaalisuuden pysyvyyden käsityksiä sekä niihin liittyviä yhteiskunnallisia normeja kuvaten tapoja, joilla seksuaalisuuden ja sukupuolen kokeminen ja käytännöt liikkuvat, kehittyvät ja vuorovaikuttavat eletyissä transsukupuolisuuden ruumiillistumissa. Haastattelen kuutta suomalaista, syntymässä naiseksi määriteltyä transsukupuolista henkilöä liittyen heidän kokemuksiinsa sukupuolesta, seksuaalisuudesta ja näiden muutoksista heidän tähänastisen elämänsä aikana. Tarkastelen nauhoitettuja ja litteroituja haastattelutekstejä transtutkimusta, queer-teoriaa ja feminististä uusmaterialistista filosofiaa yhdistävän teoreettisen kehyksen kautta keskittyen siihen, miten sukupuoli ja seksuaalisuus vaikuttavat toistensa kehitykseen, muutokseen ja materialisoitumiseen eri elämänvaiheissa ja tilanteissa. Erityisen tärkeiksi teoreettisiksi vaikuttajiksi tutkielmassani muodostuvat Judith Butlerin Gender Trouble (2006 [1990]) -teoksessaan hahmottelema performatiivisen sukupuolen teoria, Sara Ahmedin analyysi teoksessa Queer Phenomenology. Orientations, Objects, Others (2006) ja Karen Baradin teoksessa Meeting the Universe Halfway. Quantum Physics and the Entanglement of Matter and Meaning (2007) teoretisoima toimijuudellinen realismi. Päästäkseni kiinni sukupuolen ja seksuaalisuuden yhtymäkohtiin erittelen ensin niitä ominaisuuksia ja kokemuksia, jotka näyttäytyvät haastatteluteksteissäni oleellisina seksuaalisuuden ja sukupuolen kannalta. Tarkastelen seksuaalisuutta suuntautumisen, halun ja seksuaalisten käytäntöjen näkökulmasta: vaikka nämä seksuaalisuuden aspektit ovat kiinteästi kytköksissä toisiinsa, niitä ei voi kokonaan palauttaa toisiinsa. Sukupuolta käsittelen performatiivisuuden näkökulmasta painottaen transsukupuolisiin ruumiisiin ja niiden materiaalisuuteen liittyviä erityispiirteitä. Sukupuolen ja seksuaalisuuden suhteita toisiinsa tarkastelen sekä sellaisissa tilanteissa, joissa niitä on vaikea erottaa toisistaan, että sellaisissa, joissa niiden voidaan nähdä tuottavan toinentoisiaan. Tutkielmallani on etnografisia, filosofisia ja poliittisia ulottuvuuksia. Yhtäältä tahdon kuvata ja analysoida elettyjä transsukupuolisia kokemuksia ja tuottaa tietoa vähän tutkitun ihmisryhmän todellisuudesta. Toisaalta osallistun sukupuolifilosofiseen keskusteluun ruumiillisuudesta ja sukupuolen ja seksuaalisuuden olemuksesta. Lähestyn tutkimusprosessiani niin sanotusta transgender standpoint -näkökulmasta; kirjoitan transsukupuolisena ruumiina, transsukupuolisia ruumiita koskien, pyrkimyksenäni edistää elävien transsukupuolisten ruumiiden asemaa, toimijuutta ja näkyvyyttä yhteiskunnassa.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The Horne-Östberg questionnaire partly covers some factors that may be important determinants of peak time and characterize patterns of behavior. We conducted a study for the evaluation of self-reported behavioral states (hunger sensation, availability for study, physical exercise, solving daily problems, and time preferences) as expressions of underlying cyclic activity. Three hundred and eighteen community subjects without history of medical, psychiatric, or sleep disorders were evaluated in a cross-sectional design. A self-report about daily highest level of activity was used to categorize individuals into morning, evening, and indifferently active. Time-related behavioral states were evaluated with 23 visual analog questions. The responses to most analogic questions were significantly different between morning and evening active subjects. Logistic regression analysis identified a group of behaviors more strongly associated with the self-reported activity pattern (common wake up time, highest subjective fatigue, as well as wake up, bedtime, exercise and study preferences). These findings suggested that the patterns of activity presented by normal adults were related to specific common behavioral characteristics that may contribute to peak time.