1,140 research outputs found
Linking Star Formation and Black Hole Mass Growth in External Galaxies
Active galactic nuclei (AGNs) count among the most extreme phenomena in astrophysics. An AGN lies at the center of an active galaxy and at the heart of an AGN lies in turn a supermassive black hole (SMBH). Multiple connections have been found between the central SMBH and the bulge of its host galaxy. A co-evolution is implied from this, as a bulge is typically more massive than the SMBH at its center by virtually always more than a factor of 100.
Some objects from the so-called low-luminosity type-1 quasi-stellar object (LLQSO) sample have been analyzed with respect to black hole mass - bulge luminosity relations for inactive galaxies. It was found that LLQSOs deviate from these relations either due to undermassive SMBHs or overluminous bulges. The latter is a more likely explanation, as there are signs for star formation in the bulges. This work increases the previous sample size by almost a factor of 2 and examines findings in the context of the overall larger sample.
The additional LLQSOs were observed in two epochs in 2019, utilizing the New Technology Telescope equipped with the near-infrared instrument SOFI. Bulge magnitudes as substitutes for the luminosities are found from K-band imaging, while long-slit spectroscopy, covering roughly the H- and K-band, enables the identification of diagnostic lines and SMBH mass estimates.
The addition of the new LLQSOs to the previously analyzed objects within the same diagram reveals a similar scatter for both samples. LLQSOs lie on average below the suggested literature relations for inactive galaxies, strengthening previous findings significantly. Furthermore, the new LLQSOs also show signs for star formation based on spectral features that originate from molecular gas. The results support a scenario, in which star formation precedes the growth of the SMBH. This matches the idea of a trajectory of LLQSOs in the diagram, that first shifts these objects away from literature relations and subsequently back towards these
Eine unbekannte Schrift von Bernardino Ochino
Recent work on the edition of Heinrich Bullinger’s correspondence from the year 1546 has unearthed an interesting letter by Ambrosius Blarer, the reformer of Constance. In a list of publications connected with the raging Schmalkaldic War, he mentions the pamphlet “Ein gesprech des Teütschen Lands und der hoffnung diese gegenwertige Kriegsleüff betreffend […]”, attributing it to the Italian reformer Bernardino Ochino. This article corroborates Ochino’s hitherto unknown authorship, as well as providing an edition of the pamphlet with a commentary and analysis
Toward composing variable structure models and their interfaces: a case of intensional coupling definitions
In this thesis, we investigate a combination of traditional component-based and variable structure modeling. The focus is on a structural consistent specification of couplings in modular, hierarchical models with a variable structure. For this, we exploitintensional definitions, as known from logic, and introduce a novel intensional coupling definition, which allows a concise yet expressive specification of complex communication and interaction patterns in static as well as variable structure models, without the need to worryabout structural consistency.In der Arbeit untersuchen wir ein Zusammenbringen von klassischer komponenten-basierter und variabler Strukturmodellierung. Der Fokus liegt dabei auf der Spezifikation von strukturkonsistenten Kopplungen in modular-hierarchischen Modellen mit einer variablen Struktur. Dafür nutzen wir intensionale Definitionen, wie sie aus der Logik bekannt sind, und führen ein neuartiges Konzept von intensionalen Kopplungen ein, welches kompakte gleichzeitig ausdrucksstarke Spezifikationen von komplexen Kommunikations- und Interaktionsmuster in statischen und variablen Strukturmodellen erlaubt
Quantitatively consistent computation of coherent and incoherent radiation in particle-in-cell codes - a general form factor formalism for macro-particles
Quantitative predictions from synthetic radiation diagnostics often have to
consider all accelerated particles. For particle-in-cell (PIC) codes, this not
only means including all macro-particles but also taking into account the
discrete electron distribution associated with them. This paper presents a
general form factor formalism that allows to determine the radiation from this
discrete electron distribution in order to compute the coherent and incoherent
radiation self-consistently. Furthermore, we discuss a memory-efficient
implementation that allows PIC simulations with billions of macro-particles.
The impact on the radiation spectra is demonstrated on a large scale LWFA
simulation.Comment: Proceedings of the EAAC 2017, This manuscript version is made
available under the CC-BY-NC-ND 4.0 licens
Acceder caminando a los humedales urbanos: una oportunidad de recreación y bienestar
Urban wetlands in Chilean cities are one of the urban ecosystems most affected by real estate developments. Despite their importance for recreation and biodiversity, they are constantly shrinking due to deficient urban planning processes. However, with the recent boom of green and sustainable cities, wetlands are being revalued through restoration projects and open urban parks, with natural value for the well-being of habitats and the urban population. In this sense, promoting accessibility through suitable infrastructure will contribute to improving the quality of life of inhabitants and the urban environment, specifically through the integration of blue-green infrastructure. Walkable access to a network of wetlands called "La Ruta del Agua" (“the water trail”) has been analyzed here, through a perception-based survey, looking to improve access to nature in cities. The urban wetlands assessed comprise five ecosystems located in different types of neighborhoods in the metropolitan area of Concepción, Chile. Although this is a local case study, it is relevant from a methodological perspective, given the existence of a large number of degraded urban wetlands in Latin America that are in danger of disappearing. The results show that wetlands are accessible by walking, but the fact that they are rarely visited, despite being close to residential areas, reveals a lack of integration as open green spaces, rich in biodiversity, and as places of recreation in the city of Concepción. The results of this study are valuable for the design of future “wetland parks”, one which must consider the ecosystem values, biodiversity, and recreation for people’s well-being.Los humedales de las ciudades chilenas constituyen uno de los ecosistemas urbanos más afectados por los desarrollos inmobiliarios. A pesar de sus valores en recreación y en biodiversidad, sufren una constante pérdida de superficie, debido a deficientes procesos de planificación urbana. Sin embargo, ante el auge de las ciudades verdes y sustentables, se están revalorizando por medio de proyectos de restauración y de parques urbanos abiertos, de valor natural para el bienestar de los hábitats y la población. En este sentido, propiciar una accesibilidad con una infraestructura adecuada aportará a mejorar la calidad de vida de los habitantes y por supuesto del entorno urbano, concretamente a través de la integración de infraestructura verde-azul (blue-green infrastructure). Con la finalidad de contribuir al acceso a la naturaleza en ciudades, se realiza aquí un análisis de accesibilidad a pie, a una red de humedales llamada “La Ruta del Agua”, mediante una encuesta de percepción. Los humedales urbanos evaluados son 5 ecosistemas con distintos entornos barriales en Concepción Metropolitano (Chile). Si bien se trata de un caso de estudio local, representa una contribución metodológica relevante, dada la existencia de una gran cantidad de humedales urbanos degradados en Latinoamérica y en peligro de desaparecer. Los resultados de acceso muestran que los humedales son accesibles por vía de la caminata, pero el hecho de que sean poco visitados, pese a su cercanía a las zonas residenciales, revela su falta de integración como espacios abiertos, verdes, ricos en biodiversidad y aptos para la recreación en la ciudad de Concepción. Los resultados de este estudio son valiosos para el diseño de futuros de proyectos de parques en humedales, parques que deben considerar los valores ecosistémicos, la biodiversidad y la recreación para el bienestar de las personas
Survival data of patients with breast cancer who were treated in the university hospital of Essen (West German Cancer Center) (First contac 1995-1999)
Mit der hier vorliegenden Untersuchung erfolgte die retrospektive Ermittlung der Überlebenszeiten derjenigen Patientinnen, die sich zwischen 1995 und 1999 mit der Diagnose eines metastasierten Mammakarzinoms in der Spezialambulanz der Inneren Klinik (Tumorforschung) des Universitätsklinikums Essen erstmalig vorstellten und in der Folge behandelt wurden. Dabei wurden – wegen der oben beschriebenen unterschiedlichen Prognose - besonders die Unterschiede bezüglich des Hormonrezeptorstatus und des Metastasierungsmusters (ossär gegen viszeral) herausgearbeitet.
Die mediane Überlebenszeit der Gesamtgruppe betrug 25 Monate bei einer 4-, bzw. 5-Jahresüberlebenswahrscheinlichkeit von 24,2 und 19,3%. In Fällen mit Hormonrezeptor-negativer Erkrankung betrug die mediane Überlebenszeit 19,3 Monate, die 4-, bzw. 5-Jahresüberlebenswahrscheinlichkeit lag bei 13,3 und 9,3%. Patientinnen mit initial hepatischer Metastasierung erreichten hingegen nur eine mediane Überlebenszeit von 23,6 Monaten bei einer 4- und 5-Jahresüberlebenswahrscheinlichkeit von 20,9, bzw. 11,9%.
Die ermittelten Überlebenszeiten liegen damit geringfügig über denen, die in der neueren Literatur angegeben werden, obwohl etliche der neueren Medikamente (z.B. Trastuzumab bei Erkrankung mit Her2-Überexpression) für viele dieser Patientinnen noch nicht zur Verfügung standen
Development and Operationalisation of Local Sustainability Indicators - A Global South Perspective on Data Challenges and Opportunities for GIScience (Short Paper)
Evaluating and monitoring the sustainable development of nations and cities requires sets of indicators. Such indicator sets should measure equity, health, environmental, or governmental progress or recess - among other sustainability aspects. In 2015 the United Nations ratified 17 Sustainable Development Goals (SDG) assessed through 231 indicators. However, other - local - sets of indicators have been developed too. In this paper we review geodata challenges that emerged when we developed four sustainability indicator sets in Chile. Faced challenges include (geo)data availability and data representativeness, among others. We analyse how GIScience knowledge has contributed to indicator development and outline three priority research topics: (i) updating indicators based on automated processes, while respecting representativeness, (ii) tools for planning scenario generation, and (iii) methods for short- and long-term forecasting
The different worlds of inequality: Psychological determinants and implications of economic inequality
Social and economic inequalities have been a concern in human societies throughout history. In recent years especially wealth and income inequality have been the focus of controversial public, political, and scientific debates. The present thesis seeks to contribute to the ongoing inequality debate by regarding economic inequality from a psychological point of view. Together with Detlef Fetchenhauer, Thomas Schlösser, and Daniel Ehlebracht, I experimentally investigated the psychological determinants and consequences of economic inequality in three different studies. Of the many aspects that inequality comprises, we particularly focused on the association between inequality and justice (Chapter 2 and Chapter 3) as well as its consequences for affects, emotions, and cooperation (Chapter 2 and Chapter 4).
In this context, inequality as conceived in Chapter 2 might be most comparable to income inequality because it emerges as a consequence of individuals’ performance in a working task. Inequality as conceived in Chapter 3 and Chapter 4 might be most comparable to wealth inequality because it is the result of a random assignment to an advantageous or disadvantageous societal position, as is inheritance. Nevertheless, all inequalities examined within this research project are closely related, as they share an economic or monetary basis.
In Chapter 2, we experimentally explored the emotional and affective consequences of inequality and their association to justice perceptions. In particular, our participants had to solve effort-based tasks and were assigned to compensation systems referred to as tournament system and equality system. Whereas tournament systems evoked high outcome disparities, equality systems, as they were applied, caused equal outcome distributions. In accordance with prior research (e.g., Schlösser & Fetchenhauer, 2015), we found that the equality system was perceived to be more just than the tournament system. Yet, the effect of the system’s justice on affect and emotions was found to be small and both appeared, instead, to be crucially determined by the income and the status of a participant within a given system. For instance, those that benefited from the unequal tournament system perceived the system to be unjust but reported the highest positive affect and the lowest negative affect, anger, and guilt. A possible explanation might be that—within our research paradigm—beneficiaries cannot be hold accountable for the negative consequences of the exogenously determined compensation systems which might detach their justice perceptions and affects as well as emotions.
In Chapter 3, we investigated whether a person’s personal sensitivity towards justice (i.e., justice sensitivity) predicts equality preferences in democratic systems. Prior research found that unequal distributions are likely to be perceived as unjust (e.g., Deutsch, 1975), hence, we assumed that persons who are truly concerned about the just treatment of others (i.e., other-sensitive persons) hold a genuine preference for equal distributions and low inequality. Persons who show the tendency to predominantly care about a just treatment for themselves (i.e., victim-sensitive persons) were instead assumed to hold no genuine distributional preferences, but rather prefer the degree of inequality within their monetary self-interest. With the help of a so-called welfare state game (e.g., Biniossek & Fetchenhauer, 2007; Lotz & Fetchenhauer, 2012), we measured equality preferences in a democratic decision-making process. Indeed, other-sensitive persons displayed a general preference for low inequality irrespective of whether they financially gained or lost out on that decision. In contrast, victim-sensitive persons preferred either low inequality or high inequality depending on whether the one or the other was in their financial interest.
In Chapter 4, we finally investigated the relationship between democratically determined economic inequality and cooperation. Based on previous research which found that in particular endogenously induced inequality harms preconditions for cooperative behavior, such as trust (e.g., Greiner et al., 2012), we assumed that democratically induced inequality hampers cooperation. In accordance with this assumption, we found that groups which previously implemented high inequality through a majority choice displayed relatively low levels of cooperation compared to groups which previously implemented low inequality. In addition, we found that the mechanism driving this effect is likely based on motivated reasoning rather than based on self-selection, similarity, risk, or inequality aversion. These findings suggest that high degrees of inequality harm cooperation in democratic systems.
Chapter 5 provides an integrative discussion of the presented empirical research findings, while Chapter 6 suggests possible paths for future research
High-Yield Optical Undulators Scalable to Optical Free-Electron Laser Operation by Traveling-Wave Thomson-Scattering
All across physics research, incoherent and coherent light sources are extensively utilized. Especially highly brilliant X-ray sources such as third generation synchrotrons or free-electron lasers have become an invaluable tool enabling experimental techniques that are unique to these kinds of light sources. But these sources have developed to large scale facilities and a demand in compact laboratory scale sources providing radiation of similar quality arises nowadays.
This thesis focuses on Traveling-Wave Thomson-Scattering (TWTS) which allows for the realization of ultra-compact, inherently synchronized and highly brilliant light sources. The TWTS geometry provides optical undulators, through which electrons pass and thereby emit radiation, with hundreds to thousands of undulator periods by utilizing pulse-front tilted lasers pulses from high peak-power laser systems. TWTS can realize incoherent radiation sources with orders of magnitude higher photon yield than established head-on Thomson sources. Moreover, optical free-electron lasers (OFELs) can be realized with TWTS if state-of-the-art technology in electron accelerators and laser systems is utilized. Tilting the laser pulse front with respect to the wavefront by half of this interaction angle optimizes electron and laser pulse overlap by compensating the spatial offset between electrons and the laser pulse-front at the beginning of the interaction when the electrons are far from the laser pulse axis. The laser pulse-front tilt ensures continuous overlap between electrons and laser pulse while the electrons cross the laser pulse cross-sectional area. Thus the interaction distance can be controlled in TWTS by the laser pulse width rather than laser pulse duration. Utilizing wide, petawatt class laser pulses allows realizing thousands of optical undulator periods.
This thesis will show that TWTS OFELs emitting ultraviolet radiation are realizable today with existing technology for electron accelerators and laser systems. The requirements on electron bunch and laser pulse quality of these ultraviolet TWTS OFELs are discussed in detail as well as the corresponding requirements of TWTS OFELs emitting in the soft and hard X-ray range. These requirements are derived from scaling laws which stem from a self-consistent analytic description of the electron bunch and radiation field dynamics in TWTS OFELs presented within this thesis. It is shown that these dynamics in TWTS OFELs are qualitatively equivalent to the electron bunch and radiation field dynamics of standard free-electron lasers which analytically proves the applicability of TWTS for the realization of an optical free-electron laser.
Furthermore, experimental setup strategies to generate the pulse-front tilted TWTS laser pulses are presented and designs of experimental setups for the above examples are discussed. The presented setup strategies provide dispersion compensation, required due to angular dispersion of the laser pulse, which is especially relevant when building compact, high-yield hard X-ray TWTS sources in large interaction angle setups. An example of such an enhanced Thomson source by TWTS, which provides orders of magnitude higher spectral photon density than a comparable head-on interaction geometry, is presented, too.Inkohärente und kohärente Lichtquellen werden in allen Feldern der physikalischen Forschung intensiv eingesetzt. Im Besonderen ermöglichen hoch-brilliante Röntgenquellen, wie Synchrotrone der dritten Generation und Freie-Elektronen Laser, einzigartige Experimentiertechniken wodurch diese zu unverzichtbaren Werkzeugen wurden. Sie sind allerdings auch im Umfang zu Großforschungseinrichtungen herangewachsen. Um den hohen Bedarf an hoch-brillianten Lichtquellen zu decken, besteht daher die Notwendigkeit neuartige und kompakte Quellen zu entwickeln welche auf dem Maßstab eines Labors realisierbar sind.
Diese Dissertation widmet sich der Traveling-Wave Thomsonstreuung (TWTS) welche die Realisierung ultra-kompakter, intrinsisch synchronisierbarer und hoch-brillianter Röntgenquellen ermöglicht. TWTS ist eine Methode der Streuung von Laserpulsen an relativistischen Elektronen. Dabei durchquert ein Elektronenpuls mit nahezu Lichtgeschwindigkeit einen Laserpuls. Während der Durchquerung beginnen die Elektronen im Feld des Laserpulses zu oszillieren wobei sie Strahlung emittieren. Die ausgesandte Strahlung besitzt eine deutlich kürzere Wellenlänge als das Laserfeld aufgrund der hohen Elektronengeschwindigkeit und der damit verbundenen großen Dopplerverschiebung. Das besondere an TWTS ist, dass Elektronen- und Laserpropagationsrichtung einen Winkel einschließen sowie pulsfrontverkippte Hochleistungslaserpulse eingesetzt werden. Dadurch können um Größenordnungen längere Interaktionsdistanzen als in herkömmlichen frontalen Thomsonstreuungsanordnungen erreicht werden. TWTS ermöglicht dadurch die Realisierung optischer Freie-Elektronen Laser (OFEL) und inkohärenter Strahlungsquellen mit einer um Größenordnungen erhöhten Photonenausbeute gegenüber Thomsonstreuungsquellen in frontalen Interaktionsanordungen. Werden modernste Elektronenbeschleuniger und Lasersysteme genutzt, dann ist der Betrieb optischer Freie-Elektronen Laser bereits heute mit TWTS möglich.
Das wird in der Dissertation am Beispiel eines Vakuumultraviolettstrahlung emittierenden TWTS OFEL gezeigt. Dessen Anforderungen an die Qualität der Elektronen- und Laserpulse werden im Detail in der Arbeit besprochen sowie weitere Beispiele weicher und harter Röntgenstrahlung emittierender TWTS OFEL präsentiert. Diese Anforderungen werden anhand von Skalierungsvorschriften ermittelt welche aus einer selbstkonsistenten, 1.5 dimensionalen Theorie zur Wechselwirkung zwischen Elektronen und Laserfeld in TWTS abgeleitet sind. Sowohl die Theorie zur Wechselwirkung als auch die Ableitung der Skalierungsvorschriften sind Teile dieser Dissertation. Eine wichtige Erkenntnis der Theorie ist die qualitative Äquivalenz von Elektronen- und Strahlungsfeldbewegungsgleichungen in TWTS zu denen herkömmlicher Freie-Elektronen Laser. Das beweist analytisch die Möglichkeit zur Realisierung eines OFEL mit TWTS.
Einen weiteren wichtigen Teil dieser Dissertation bildet die Arbeit zur Generierung der Laserpulse mit verkippter Pulsfront. Optische Aufbauten zur Verkippung der Laserpulsfront werden vorgestellt und für einige der präsentierten TWTS OFEL ausführlich dargelegt. Die Aufbauten verkippen nicht nur die Laserpulsfront sondern gewähren gleichzeitig Kontrolle über die Laserpulsdispersionen. Dadurch kann während der gesamten Interaktionen eine ausreichend hohe Qualität des Laserfeldes sichergestellt werden, was für TWTS OFEL und inkohärente TWTS Lichtquellen mit großem Interaktionswinkel unbedingt notwendig ist. Ein Beispiel einer inkohärenten TWTS Lichtquelle wird ebenfalls präsentiert. Diese emittiert Strahlung mit einer um Größenordnungen höheren spektrale Photonendichte als eine herkömmliche Thomsonquelle in einer frontalen Streuanordnung mit vergleichbaren Laser- und Elektronenpulsen
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