Transverse Target Spin asymmetries in exclusive ρ0\rho^0 muoproduction

Generalized Parton Distributions (GPDs) provide a dynamical picture of the nucleon. The exclusive production of $\rho^0$ mesons on a transversely polarised target is sensitive to the nucleon helicity-flip GPDs $E$ which are related to the total angular momentum of quarks and gluons. In 2007 and 2010 the COMPASS experiment at CERN collected data by scattering a 160 GeV/c muon beam off a transversely polarised NH$_3$ target. The final state particles were detected with the two-stage spectrometer with high resolution tracking. In this talk new results for the azimuthal asymmetries $A_{\text{UT}}$ and $A_{\text{LT}}$ are presented.Comment: Conference: C13-04-2

IT Multisourcing Management : A Qualitative Study from the Vendor's Perspective

IT multisourcing is an outsourcing method that combines services of various different vendors in a single technology focused undertaking. This study investigates the benefits and disadvantages that an IT multisourcing setting presents to the vendor from a management perspective. As vendors are responding to client needs, studying their experiences can present valuable information for managing IT multisourcing projects for client companies and their decision makers. The study aims to gather as much information of multisourcing from the vendors’ perspective, but due to the main focus in previously conducted research articles being on the client’s side, there is a gap in research to be filled. This study aims to fill the gap by interviewing eight IT industry experts with experience from IT outsourcing and multisourcing projects. As multisourcing describes a situation where one client contracts two or more independent vendors on a single IT project or undertaking, it is also a situation where the different tasks assigned to vendors have some impact on each other. This is true in most cases, even though the vendors may operate independently from each other. It has been shown that multisourcing is only efficient when vendors are communicating with each other. This study also focuses on examining the communication and cooperation activities of the various operators in a multisourcing setting. Through examination of a selection of most ocmmonly used models in IT multisourcing, the thesis aims to expand the knowledge on what the benefits and disadvantages of IT multisourcing are as well as what the management challenges in these settings are with an emphasis on the vendor's view point

Money and a Room of One’s Own?! A Feminist Deconstruction of the Situation of Female Jazz Musicians 1960–1980

‘What does it take for a woman to be able to write a novel?' asks Virginia Woolf in A Room of One's Own. The answer is surprisingly mundane: She needs money and a room of her own. Although Woolf writes at length about passion and talent, she concludes that material preconditions are actually more crucial. Similarly, the present article argues that there has been no lack of interest in jazz among female musicians, but a lack of socially accepted possibilities for professionalisation. This article endeavours to deconstruct some of the socio-cultural contexts and frameworks of music-making in a feminist way. To this end, the most crucial findings from semi-structured interviews with Norma Winstone, Sidsel Endresen, Aki Takase and Uschi Brüning are presented and discussed. To contextualise the interviews, Bourdieu's analyses of the academic and literary fields will be referred to with relation to the institutionalisation of jazz, while questions of canonicity and historiography will be discussed, as well as questions surrounding performativity and corporeality. Linking up with research surrounding these issues in other musical styles, this article attempts to map and contextualise the debate about gender and the arts in its complex, sometimes controversial and even paradoxical dynamic

Unusual synchronization phenomena during electrodissolution of silicon: the role of nonlinear global coupling

The photoelectrodissolution of n-type silicon constitutes a convenient model system to study the nonlinear dynamics of oscillatory media. On the silicon surface, a silicon oxide layer forms. In the lateral direction, the thickness of this layer is not uniform. Rather, several spatio-temporal patterns in the oxide layer emerge spontaneously, ranging from cluster patterns and turbulence to quite peculiar dynamics like chimera states. Introducing a nonlinear global coupling in the complex Ginzburg-Landau equation allows us to identify this nonlinear coupling as the essential ingredient to describe the patterns found in the experiments. The nonlinear global coupling is designed in such a way, as to capture an important, experimentally observed feature: the spatially averaged oxide-layer thickness shows nearly harmonic oscillations. Simulations of the modified complex Ginzburg-Landau equation capture the experimental dynamics very well.Comment: To appear as a chapter in "Engineering of Chemical Complexity II" (eds. A.S. Mikhailov and G.Ertl) at World Scientific in Singapor

Interaction Of Hydrogen With A Pd(210)- And A Ni(210) Surface

Titelseite und Inhaltsverzeichnis 0\. Einleitung 5 1\. Allgemeiner Teil 7 1.2. Die (210)-Oberfläche 7 1.2. Allgemeines zur H-Adsorption 10 1.3. Dissoziation von Wasserstoff auf Metalloberflächen 13 1.4. Zur Bindung von Wasserstoffmolekülen an Metalloberflächen 23 1.5. Beispiele für molekularen Wasserstoff auf Metalloberflächen 30 2\. Experimenteller Teil 35 2.1. Augerelektronenspektroskopie (AES) 35 2.3. Beugung langsamer Elektronen (LEED) 37 2.3. Thermodesorptionsspektroskopie (TDS) 40 2.4. Änderung der Austrittsarbeit 44 2.5. Photoemissionsspektroskopie (UPS) 47 2.6. Schwingungsspektroskopie (HREELS) 53 2.7. Apparativer Aufbau 60 2.8. Substrate 63 2.9. Probenpräparation 65 Motivation 67 3\. Untersuchungen der reinen Wasserstoffsysteme H2/Pd(210) und H2/Ni(210) 69 3.1. Wechselwirkung von Wasserstoff mit einer Pd(210)-Oberfläche 69 3.2. Wechselwirkung von Wasserstoff mit einer Ni(210)-Oberfläche 86 4\. Zur konkurrierenden Adsorption von atomaren und molekularen Wasserstoff 101 5\. Untersuchungen zum Subsurface-Zustand 118 6\. Das H2/CO/Pd(210)-Koadsorptionssystem 130 6.1. Das reine CO/Pd(210)-System 131 6.2. Die H/CO Koadsorption auf der Pd(210)-Oberfläche 138 6.3. Diskussion 144 7\. Diskussion 150 8.1. Zusammenfassung 167 8.2. Summary 169 9\. Literatur 1718 In der vorliegenden Arbeit wurde die Wechselwirkung von Wasserstoff mit einer Pd(210)- und Ni(210)-Oberfläche mit Hilfe von Thermodesorptionsspektren (TDS), Messungen der Austrittsarbeitsänderung (DF), Photoemissionsspektren (UPS), Elektronenenergieverlustspektren (HREELS) und H2/D2-Isotopenaustausch- Messungen untersucht. Das H2-Adsorptionsverhalten stimmt für beide Oberflächen stark überein: Bei Temperaturen größer als 100K adsorbiert Wasserstoff spontan dissoziativ und bildet unter Erhöhung der Austrittsarbeit drei atomare Bindungszustände. Wird die Adsorptionstemperatur auf 50K reduziert, adsorbiert der Wasserstoff zusätzlich molekular in zwei Chemisorptionszustände. Dabei wird die Austrittsarbeit vermindert. Die molekulare Natur dieser Zustände wurde mit Hilfe von H2/D2-Austauschexperimenten, durch die Beobachtung einer H-H-Schwingungsbande im HREELS und der Detektion von s-H2/Pd- bzw. s*-H2/Pd- Bindungszuständen im UPS belegt. Neben den relativ hohen Desorptionstemperaturen weist auch die energetische Lage der Signale in den HREEL- und UP-Spektren eine chemisorptive Wechselwirkung nach. Die in den UP- Spektren beobachtete H2-induzierte Änderung der d-Bandstruktur kann mit einem Bindungsmodell entsprechend dem s-Hin/p-Rückbindungs-Synergismus nach Dewar- Chatt-Duncanson bzw. Blyholder erklärt werden. Die Beobachtung von chemisorbierten H2-Molekülen auf einer Übergangsoberfläche ist ungewöhnlich. Nach dem Harris-Andersson-Modell sollte auf Übergangsmetallen die Dissoziation spontan erfolgen, auf Edelmetallen hingegen inhibiert sein. Hier können bei Temperaturen kleiner als 10K molekular physisorbierter Wasserstoff stabilisiert werden. Das heißt, es besteht nur eine schwache Van-der-Waals-Wechselwirkung zwischen Molekül und Oberfläche. Das einzige weitere Beispiel von molekular chemisorbiertem Wasserstoff auf einer Übergangsmetalloberfläche ist das von A.-S. Mårtensson untersuchte H2/Ni(510)-System. Ist diese gestuften Ni(110)-Oberfläche mit atomarem Wasserstoff gesättigt, adsorbiert weiterer Wasserstoff molekular an den Stufen. Aus HREELS-Daten ergibt sich eine on top Adsorption. Wir machen ähnliche Beobachtungen: Während die atomare Adsorption auf der Pd(210)- bzw. Ni(210)-Oberfläche in hochkoordinierte Plätze erfolgt, adsorbiert das Molekül on top auf Substratatomen der ersten Lage. DF\- und TD- Experimente deuten darauf hin, daß zur Stabilisierung der molekularen Zustände eine partielle atomare Vorbelegung der Oberfläche notwendig ist. Mit Hilfe des in einer Kooperation mit einer Theoretischen Gruppe (A. Groß an der TU München) entwickelten Adsorptionsmodells wird den verschiedenen molekularen Desorptionssignalen derselbe Adsorptionsplatz bei unterschiedlicher atomarer Vorbedeckung zugeordnet. Der molekulare Adsorptionsplatz on top an den gering koordinierten Substratatomen der ersten Lage ist gleichzeitig der Dissoziationsplatz. Ändert sich aufgrund der benachbarten atomaren Adsorption von Wasserstoff die d-Bandstruktur und damit die Reaktivität dieser ausgezeichneten Substratatome, wird der dort gebildete molekulare Vorläufer- Zustand stabilisiert. Die in dieser Arbeit vorgestellten Systeme unterscheiden sich im Hinblick auf die Besetzung des Subsurface-Zustandes. Für die Pd(210)-Oberfläche wird eine Absorption von Wasserstoff in oberflächennahe Zwischengitterplätze beobachtet, für die H2/Ni(210)-Oberfläche nicht. Dabei ist mit Besetzung des Subsurface- Zustandes keine Änderung der Austrittsarbeit oder die Detektion eines Schwingungsverlustes im HREELS verbunden. In den TD-Spektren wird der Absorption ein schmales Niedertemperatur-Signal zugeordnet. Diese Beobachtung wird mit Hilfe des von Okuyama entwickelten Stamping-Modells diskutiert. Eine H-Absorption wurde bereits für andere offene Pd-Oberflächen ( (110) und (310) ) beobachtet und gilt als besondere Elementeigenschaft von Palladium. Im Unterschied zu den Pd(110)- und Pd(310)-Oberflächen ist zur Absorption in den Pd(210)-Kristall keine Rekonstruktion nötig. Dies und die Beobachtung der Abhängigkeit der Absorptionsgeschwindigkeit von der Probenpräparation ist Anlaß dafür die Existenz eines zur Absorption notwendigen Strukturensembles auf der nicht-rekonstruierten Pd(210)-Oberfläche zu diskutieren. Als solches wird der vierfachkoordinierte Muldenplatz und sein benachbarter dreifachkoordinierter (111)-Mikrofacettenplatz identifiziert. Daneben wurde auch die H/CO-Koadsorption auf der Pd(210)-Oberfläche untersucht. Wenn Wasserstoff präadsorbiert und anschließend CO dosiert wird, beobachten wir eine H/CO-Komplexbildung. Dies wird durch die Detektion eines sogenannten S-Signals im H2-TD-Spektrum und eines nH-O-Schwingungsverlustes im HREELS belegt. Im Gegensatz zu anderen Koadsorptionssystemen desorbiert der S-Wasserstoff nicht bei den niedrigeren Temperaturen des Desorptionsbereiches, sondern simultan mit dem Stabilsten der CO-Zustände. Dies deutet auf eine ungewöhnlich stabile Komplex-Bildung hin.8 This work presents investigations of the interaction of hydrogen with a Pd(210) and Ni(210) surface using LEED (low energy electron diffraction), thermal desorption spectroscopy (TDS), work-function measurements (DF),vibrational loss measurements (HREELS), and isotope exchange experiments. The interaction of hydrogen with both surfaces is very similar. For temperatures above 100K, hydrogen chemisorbs spontaneously forming atoms in three binding states (b1, b2, b3). The atomic adsorption leads to a work function increase. If the temperature is reduced to 50K, hydrogen additionally chemisorbs into two molecular states (g1, g2). In contrast to the b-adsorption, the population of g-states induces a work-function decrease. The molecular nature of the g-states was confirmed by observation of the H-H vibration mode in HREELS, by the detection of the s-H2/Pd- and s*-H2/Pd- bonding in UPS, and by H2/D2-exchange experiments. The energy range of the HREELS- and UPS-signals and the relatively high desorption temperature in TD-spectra verify a real chemisorptive interaction between molecule and surface. We consider a side-on complex configuration which allows a s/s*-synergism equivalent to the Blyholder backbonding mechanism for CO chemisorption or the classical Dewar-Chatt-Duncanson model for the bonding situation in olefine or other organometallic complexes. A molecular chemisorption of H2 on a transition metal surface is unusual. In general, hydrogen adsorbs dissociatively. While on noble metals the dissociation is hindered by a sizable energy barrier, it occurs spontaneously on transition metal surfaces. If molecular adsorption states exist, they are usually very weakly bound in shallow physisorption wells; beyond, it requires surface temperatures below 20K to stabilize those states. At Ni(510), molecular chemisorption has been observed at surface temperatures up to 125K, presumably at the steps, but only after the surface was passivated with a dense atomic layer. We made similar observations, namely the coexistence of chemisorbed molecular and atomic hydrogen on the relatively open Pd(210) and Ni(210) surfaces although the surfaces were not fully passivated. While the atomic adsorption takes place in high coordinated sites, the molecule adsorbs on top. It is very difficult to identify experimentally the exact location and nature of the hydrogen adsorption states. In order to obtain this microscopic information, A. Groß et al. performed DFT calculations. The results suggest that the hydrogen molecule is first attracted to the top Pd atoms. At the clean Pd(210) surface, no stable molecular adsorption state should exist and the hydrogen molecule dissociates into the higher coordinated sites. Due to the presence of atomic hydrogen on the surface however, this behavior changed considerably. The presence of hydrogen atoms leads to a molecular adsorption state at the top site. That the top site`s reactivity is hardly influenced by the pre-adsorbed hydrogen atoms can be traced back to the induced change in the local density of states. In the case of Pd, we observed the absorption of hydrogen atoms which reside ?close to the surface?. Evidence for such a ?subsurface state? is a low- temperature thermal desorption feature which cannot be saturated, combined with a vanishing work function change and negligible vibrational loss contributions of the respective H state. We discuss our observations using the stamping model developed by Okuyama. The hydrogen absorption has already been observed on other open palladium surfaces and is considered as a specific feature of the element palladium. But in contrast to other open Pd surfaces, the Pd(210) surface need not to reconstruct for absorption. Futhermore, the absorption velocity depends on the preparation of the sample. Both observations give rise to the assumption that a certain ensemble of substrate atoms necessary for chemisorption exists on the non-reconstructed Pd(210) surface. We can identify this ensemble as the four-fold coordinated hollow site and the neighbouring three-fold coordinated site. In addition, we examined the H/CO-coadsorption on the Pd(210) surface. If the Pd crystal was first exposed to hydrogen and then to carbon monoxid, we observed the formation of H/CO-complexes. This observation was verified by the detection of a so-called S desorption signal in TDS and by a O-H vibrational loss in HREELS. In contrast to other coadsorption systems the S-hydrogen does not desorb in the low temperature area. Rather, hydrogen desorbs simultaneously with the strongly bound carbon monoxid, indicating an unusually stable complex

Strategic Alliances as a form of Coopetition and its impact on the Performance of Airlines: A Case Study analysis of Lufthansa, Finnair, and Alitalia

The research on coopetition (i.e., simultaneous cooperation and competition) has increased significantly over the last two decades. Noteworthy findings have been made, including the benefits that a firm gains from such a relationship. However, only limited studies centralize the impact on performance through coopetition. Existing studies on coopetition and the effect on performance show mixed outcomes, and researchers claim that the results depend on the firm's industry. Thus, it is relevant to analyze the impact of coopetition on market performance. The following study will examine the aforementioned research gap by looking into the airline industry where coopetition relationship has been practiced in the form of strategic alliances for more than 20 years. The empirical analysis was based on a multiple case study of three airlines, from three different countries, operating in three different alliances. That allowed to investigate similarities and differences among the diverse sized companies in terms of the performance impact. Primary data were collected through semi-structured interviews. Additionally, annual reports were used as secondary data and to enhance credibility through triangulation. Findings show that in general, coopetition through strategic alliances contributes positively to airlines. Nevertheless, the degree of how much airlines benefit from alliances depends on the position in the network and the airline's size. Airlines of small size gain most from the relationship, and airlines with a central position in the alliance give more to the strategic alliances than they get out. The findings reveal that airlines of large size gain less from alliances and increasingly form other types of partnerships like joint ventures that create a more balanced give and gain relationship. Notwithstanding, the COVID epidemic will have a crucial impact on airlines and increase the importance of strategic alliances and partnerships further