267 research outputs found
Stability for Lie–Trotter products for some operator matrix semigroups
No full textCoupled systems of linear differential equations in Banach spaces can be often handled by the theory of C 0 -semigroups of operator matrices. We study the stability of Lie–Trotter products of such matrix semigroups, and present three classes of examples (abstract delay equations, abstract inhomogeneous equations, abstract dynamic boundary value problems) and some open problems. This survey is based on the papers [1], [2] and [5], to which we refer the interested reader for more details and extensive bibliographical information
ALTRUISM RECONSIDERED: EXPLORING NEW APPROACHES TO PROPERTY IN HUMAN TISSUE
No full textList of figures and tables -- List of contributors -- Acknowledgments -- 1. Introduction / Michael Steinmann -- Pt. I. Reciprocity and participation: overcoming the models of 'gift' and 'altruism' -- 2. Altruism in medical donations reconsidered: the reciprocity approach / Peter Sýkora -- 3. Notes on policy, language and human tissue / Richard Tutton -- Pt. II. Donation in the light of human embodiment -- 4. Why the body matters: the symbolic significance of human tissue / Alastair V. Campbell -- 5. Duties towards our bodies / Michael Steinmann -- Pt. III. Towards a richer understanding of property in ethics and law -- 6. Property in human tissue: triangulating the issue / Roger Brownsword -- 7. Property rights in the body a philosophical approach / Barbro Fröding -- 8. Reflections on entitlements in the human body from an equity perspective / Nils Hoppe -- Pt. IV. Models of governance: pitfalls and possibilities -- 9. Using tissue and material from the human body for biomedical research: proposals for a normative model / Christian Lenk and Nils Hoppe -- 10. Preventing conflicts of interests in the field of human biological materials: the 'contractual model' as an avant-garde / Christine Noiville -- 11. The model of trust / Caroline Mullen -- 12. Moore's Law and the taxman: some theses on the regulation of property in human tissue / Jasper A. Bovenberg -- 13. An investigation of the conception, management and regulation of tangible and intangible property in human tissue: the PropEur Project / Caroline Mullen and Heather Widdows -- Pt. V. The persisting challenges of regulation -- 14. Personal rights over an individual's biological sample stored for research / Aitziber Emaldi-Cirión -- 15. Human biological materials among civil, trade and health law: ethical, anthropological and legal implications of conflicts of law system / Catherine Labrusse-Riou -- 16. Indirect commodification of ova donation for assisted reproduction and for human cloning research: proposals for supranational regulation / Ingrid Schneider -- 17. Accessing genetic information: anomalies arising from the regulation of genetic material and genetic information in the UK / Alison Hall -- 18. Biobanks for research: the German National Ethics Council's opinion / Jochen Taupitz -- 19. European regulations on human tissue and cells transplantation / Ján Koller -- Inde
Instruments and obligations for regulating good agricultural practice - the case of documentation of pesticide use
No full textRecord-keeping of factor inputs is a key factor for farm controlling. In recent years many regulations have been introduced to establish compulsory documentation requirements, even within guidelines of good agricultural practice. Highlighting documentations of pesticide use, this paper gives an overview on the current legal and practical situation in Germany. Despite a large number of regulations, certainty about required modalities of record-keeping is low. A legal specification is upcoming. An aspect which is of greater importance than legal environment is the demand made by traders and related industry for traceability. The situation is discussed in the light of the current scope of farmers' documentation
Instruments and obligations for regulating good agricultural practice - the case of documentation of pesticide use
No full textRecord-keeping of factor inputs is a key factor for farm controlling. In recent years many regulations have been introduced to establish compulsory documentation requirements, even within guidelines of good agricultural practice. Highlighting documentations of pesticide use, this paper gives an overview on the current legal and practical situation in Germany. Despite a large number of regulations, certainty about required modalities of record-keeping is low. A legal specification is upcoming. An aspect which is of greater importance than legal environment is the demand made by traders and related industry for traceability. The situation is discussed in the light of the current scope of farmers' documentation
Suitability of vaccinia virus and bovine viral diarrhea virus (BVDV) for determining activities of three commonly-used alcohol-based hand rubs against enveloped viruses
No full textBackground A procedure for including activity against enveloped viruses in the post-contamination treatment of hands has been recommended, but so far no European standard is available to implement it. In 2004, the German Robert Koch-Institute (RKI) and the German Association for the Control of Virus Disease (DVV) suggested that vaccinia virus and bovine viral diarrhea virus (BVDV) should be used as test viruses in a quantitative suspension test to determine the activity of a disinfectant against all enveloped viruses. Methods We have studied the activities of three commonly-used alcohol-based hand rubs (hand rub A, based on 45% propan-2-ol, 30% propan-1-ol and 0.2% mecetronium etilsulfate; hand rub B, based on 80% ethanol; hand rub C, based on 95% ethanol) against vaccinia virus and BVDV, and in addition against four other clinically relevant enveloped viruses: herpes simplex virus (HSV) types 1 and 2, and human and avian influenza A virus. The hand rubs were challenged with different organic loads at exposure time of 15, 30 and 60 s. According to the guidelines of both BGA/RKI and DVV, and EN 14476:2005, the reduction of infectivity of each test virus was measured on appropriate cell lines using a quantitative suspension test. Results All three alcohol-based hand rubs reduced the infectivity of vaccinia virus and BVDV by >= 4 log10-steps within 15 s, irrespective of the type of organic load. Similar reductions of infectivity were seen against the other four enveloped viruses within 15 s in the presence of different types of organic load. Conclusions Commonly used alcohol-based hand rubs with a total alcohol concentration >= 75% can be assumed to be active against clinically relevant enveloped viruses if they effectively reduce the infectivities of vaccinia virus and BVDV in a quantitative suspension test
Mosasaurs from Germany - a brief history of the first 100 years of research
No full textIn Germany, mosasaur remains are very rare and only incompletely known. However, the earliest records date back to the 1830s, when tooth crowns were found in the chalk of the Isle of Rugen. A number of prominent figures in German palaeontology and geosciences of the 19th and 20th centuries focused on these remains, including, among others, Friedrich von Hagenow, Hermann von Meyer, Andreas Wagner, Hanns Bruno Geinitz and Josef Pompeckj. Most of these works were only short notes, given the scant material. However, the discovery of fragmentary cranial remains in Westphalia in 1908 led to a more comprehensive discussion, which is also of historical importance, as it illustrates the discussions on the highly controversial and radical universal phylogenetic theory proposed by Gustav Steinmann in 1908. This theory saw the existence of continuous lines of descent, evolving in parallel, and did not regard higher taxonomic units as monophyletic groups but as intermediate paraphyletic stages of evolution. In this idea, nearly all fossil taxa form part of these lineages, which extend into the present time, and natural extinction occurs very rarely, if ever. In Steinmann's concept, mosasaurs were not closely related to squamates but formed an intermediate member in a anagenetic chain from Triassic thalattosaurs to extant baleen whales. The newly found specimen led Josef Pompeckj to write a vehement rebuttal to Steinmann's theory, published in 1910, showing that his conclusions were conjectural and speculative, being based on convergence and not supported by scientific evidence. This particular specimen, housed in Gottingen, later also inspired a piece of palaeoart by Franz Roubal under the instructions of Othenio Abel. With the exception of a vertebra from the Campanian of former East Prussia (now Russian Federation), and a possible vertebra from the Cenomanian of Dresden, Saxony, all datable material - today partly lost - originated from the northern part of present-day Germany and stratigraphically from the Campanian-Maastrichtian. The purported record from the Cenomanian of Bavaria ( southeastern Germany) was most probably an error, based on Upper Jurassic crocodilian material
Multiphoton Ionization of Laser Cooled Lithium
No full textReaction microscopes enable kinematically complete measurements of atomic and molecular fragmentation. An ultracold atomic target is usually provided by a supersonic gas jet. The apparatus developed in the course of this thesis for the first time combines the principle of the reaction microscope with a magneto-optical trap. This allows for the preparation of lithium atoms in the sub-mK range. Being a three-electron system, its simple atomic structure makes lithium a model system of great topical interest for all kinds of ionization reactions. In order not to deteriorate the determination of the momenta of the charged fragments by the magnetic field of the trap, a pulsed mode of operation is adopted, creating field-free conditions during data acquisition and making efficient use of the stored target. The novel apparatus provides a versatile target for investigations on fragmentation of lithium by electron, ion and photon impact. For the first time, momentum-resolved measurements on multiphoton ionization in intense laser fields with pulse durations of 25~fs and peak intensities in the range between 10~W/cm and 10~W/cm were performed. The acquired photoelectron spectra exhibit unexpected structures such as a preferred emission in the direction perpendicular to the laser polarization axis, which are not fully understood yet. Presently, corresponding calculations are being done in several theory groups
Normbruch durch phonetische Interferenzen. Tabudiskurse vor dem Hintergrund der Sprechwirkungsforschung
No full textWhen speaking of linguistic taboos in an intercultural context, one generally thinks of certain linguistic behavior that is sanctioned in one culture but not in the other. Seldom considered, however, is that not only “what” is said but also “how” it is said may be viewed as offensive. Along with the subject matter that is frowned upon in some cultures – money, sex, and death are typical examples – certain aspects of foreign-language accent and speech habits, must also be considered, since they evoke similar confusion and negative reactions.
A more thorough investigation of phonetic interference as a specific cause of linguistic breaches requires that the taboo discourse be explored in the context of speech-effect research. After showing how prosodic errors occur and discussing their role in foreign-language learning, the author analyzes foreign-language speech habits and accents in terms of their culture-specific reception, noting that these phonetic elements represent sources of confusion that violate the linguistic norm and, in some cases, may be seen as taboo. The Italian accent in German as a foreign language serves as an example.
The intention here is to show that it is an undervaluation of some forms of phonetic interference to view them as merely unavoidable attributes of foreign-language speakers. Rather, it is important to consider the possibility that they represent disruptive elements that can seriously compromise intercultural verbal communication – indeed, can cause a complete rupture of the same. ----------
Wenn man von sprachlichen Tabubrüchen im interkulturellen Kontext spricht, so hat man im Allgemeinen bestimmte sprachliche Handlungen vor Augen, die in der einen Kultur sanktioniert werden, in der anderen dagegen nicht. Überlegungen dazu, dass nicht nur das „Was“, sondern auch das „Wie“ Anstoß erregen kann, werden weniger angestellt. Denn neben thematisch bedingten Tabus wie Geld, Sex, Tod etc., die in unterschiedlichen Kulturen kontroverse Bedeutungen haben können, müssen bestimmte Aspekte von fremdsprachlichem Akzent und Sprechgewohnheiten mit einbezogen werden, da sie ebensolche Irritationen verursachen und auf ähnliche Weise negative Reaktionen hervorrufen.
Um diese spezifische Form des durch phonetische Interferenzen bedingten Normbruchs genauer untersuchen zu können, muss der Tabudiskurs in den Rahmen der Sprechwirkungsforschung gestellt werden. Zunächst soll gezeigt werden, wie prosodische Fehler entstehen und welchen Stellenwert sie beim Erlernen einer Fremdsprache haben. Daraufhin wird die Sprechwirkung von fremdsprachlichen Sprechgewohnheiten und Akzenten auf ihre kulturbezogene Rezeption hin betrachtet und dargelegt, durch welche phonetischen Elemente Irritationen entstehen, die als Normverletzung, ja in einigen Fällen als Tabubruch gelten können. Als Beispiel dient der italienische Akzent im Deutschen.
Auf diese Weise soll gezeigt werden, dass die Bedeutung phonetischer Interferenzen dann unterbewertet wird, wenn man sie lediglich als unvermeidliche Eigenschaft fremdsprachlicher Sprecher betrachtet. Denn es ist möglich, dass sie ein Störfaktor sind, der das interkulturelle Gespräch massiv beeinträchtigt, ja den Abbruch desselben verursachen kann
Analytical and numerical investigations of resistive cooling of trapped ion clouds
No full textThe resistive cooling is a proven method in Penning trap physics for ion-cooling which
can be applied both to single ions and ion clouds. In Penning traps ions are stored by the
superposition of an electrical and magnetic field. The electrical field is generated by an
arrangement of electrodes whose potentials can be manipulated during the experiment,
which allows to control the frequencies of the ion dynamics externally. The electrical
field caused by the ions themselves lead to a surface charge density on the trapping
electrodes. The surface charge density is coupled to the dynamics of the ions and leads
to a current signal, which can be picked-up to drive a dissipative resonant circuit. This
changes the potential of the pick-up electrode and therefore the shape of the trapping
potential. In resonance the change of the electrical field adapts in response to the ion
motion, so that within one oscillation period the ion acceleration and the electrical field
have a coherent and an incoherent phase. Due to the imperfection of the resonant circuit
energy is converted into heat so that in the coherent phase of motion less amount of
energy is flowing back from the resonant circuit to the ions. This continues until the
ions signal disappears in the noise of the resonant circuit and no further cooling is taking
place.
In case of a single ion, the theory is in good agreement with the experiment but in case
of ion clouds no theoretical model can fully explain the measurements. In this thesis,
the resistive cooling of ion clouds from a molecular dynamic point of view is modelled,
analysed and studied numerically . The modelling attaches particular importance to the
description of the mutual coupling of the resonant circuit and the ion cloud. The model
derived for the calculation of the induced charge takes into account the full phase space
distribution of ions and exceeds in precision previous models. Further, the modelling
takes into account the electrostatic field, the magnetic field and the ion-ion interaction.
This leads to a system of coupled differential equations, which is investigated numerically
and analytically. The model includes the single ion case which is extended by a description
of the dynamics of the ion and the resonant circuit. Furthermore, the model allows
the derivation and calculation of geometrical parameters. In the case of ion clouds, the
mechanisms driving the cooling will be identified and the particular cooling behaviour
is explained based on numerical and analytical investigations.Das resistive Kühlen ist eine in der Penningfallen-Physik erprobte Methode zum Kühlen
von Ionen, die sowohl auf einzelne Ionen sowie Ionenwolken angewandt werden kann.
In Penningfallen werden Ionen durch
¨
Uberlagerung eines elektrischen und magnetischen
Feldes gespeichert. Das elektrische Feld wird durch eine Anordnung von Elektroden
erzeugt, deren Potentiale während des Experimentes extern gesteuert werden können.
Somit wird eine Kontrolle der Bewegungsfrequenzen der Ionen möglich. Das von den
Ionen erzeugte elektrische Feld verursacht in den Fallenelektroden eine an die Ionen-
dynamik gekoppelte Ladungsdichte und somit einen Strom. Wird das Signal durch einen
externen dissipativen resonanten Schwingkreis geleitet, kommt es zu einer Spannungs-
änderung an den Elektroden und somit zu einerÄnderung des elektrischen Speicherfeldes.
Diese Feldänderung passt sich in Resonanz der Ionenbewegung an, sodass sie innerhalb
einer Oszillationsperiode je zur Hälfte gleichgerichtet bzw. entgegengesetzt zur
Ionenbeschleunigung wirkt. Aufgrund der Imperfektion des Schwingkreises wird Energie
in Wärme umgewandelt und somit in der gleichgerichteten Phase weniger Energie an
die Ionen zurückgegeben als w¨ ahrend der entgegengerichteten Phase entnommen wurde.
Dies geschieht solange bis das Ionensignal im Rauschen des Schwingkreises verschwindet
und keine weitere Kühlung mehr stattfinden kann.
Im Falle einzelner Ionen erklärt die Theorie das Experiment sehr gut. Betrachtet man
allerdings Ionenwolken, gibt es kein theoretisches Modell, welches mit den im Experiment
gemessenen Kühlkurven in Einklang zu bringen ist. In dieser Arbeit wird die resistive
Kühlung von Ionenwolken aus molekulardynamischer Sicht modelliert, analysiert
sowie numerisch simuliert. Bei der Modellierung wird besonderer Wert auf die Beschreibung
der wechselseitigen Koppelung von Schwingkreis und Ionenwolke gelegt. Das dabei hergeleitete
Modell zur Berechnung der induzierten Ladung berücksichtigt die vollständige
Phasenraumverteilung der Ionen und übersteigt in Präzision bisherige Modelle. In der
Modellbildung wird darüber hinaus die elektrostatische Feldkraft, das Magnetfeld sowie
die Ion-Ion-Wechselwirkung berücksichtigt. Dies führt zu einem System von gekoppelten
Differentialgleichungen, welches sowohl numerisch als auch analytisch untersucht wird.
Das Modell inkludiert den bekannten Einteilchenfall und erweitert diesen um die Beschreibung
der Ionen- und Schwingkreisdynamik sowie um Methoden für die Berechnung geometrischer
Parameter. Im Fall von Ionenwolken kann sowohl durch numerische als auch analytische
Untersuchungen gezeigt werden, welche Mechanismen für die Kühlung von Bedeutung sind
und wie daraus der für Wolken charakteristische Kühlverlauf entsteht
Design, construction and commissioning of a gas mixing system for gaseous particle detectors
No full textThe success of gaseous particle detectors started around 1900, when first attempts were made by Curie, Townsend and Geiger. After the development of the Geiger-Müller counter, gaseous detectors have been used in many particle physics experiments and they were involved in many particle discoveries. Today gaseous particle detectors are part of the majority of particle physics experiments. A large variety of detector types has been developed until now ranging from drift tube systems for muon detectors over large volume time projection chambers to micro pattern gas detectors. For their operation gaseous detectors need gas systems, which supply the gas mixture at the needed flow and pressure. The gas system presented in this thesis can be used for research and development of gas ionisation particle detectors. During the commissioning phase and beyond, this system was used to do systematic measurements of various gas parameters. These studies help understanding gas properties and can improve detector simulations. Commissioning tests were done using one monitoring chamber, which is the same that are used for the Time Projection Chamber inside the ND280 detector of the T2K-experiment. Due to the high precision of the gas mixture, the system helps understanding the systematic effects of the monitoring chambers. At the same time possible alternative gas mixtures for the Time Projection Chamber (TPC) operation were investigated. Also a sensitivity study of the drift velocity regarding the gas composition has been done. Furthermore also other mixtures have been mixed and have been tested for future use in particle detectors. All the tests done with this system may assist the election of the gas mixture. In this thesis, the general concept and the physical results achieved during commissioning and fine tuning are presented
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