Refine
Has Fulltext
- no (23) (remove)
Document Type
- Article (11)
- Part of a Book (4)
- Doctoral Thesis (3)
- Monograph/Edited Volume (1)
- Conference Proceeding (1)
- Moving Images (1)
- Other (1)
- Review (1)
Is part of the Bibliography
- yes (23) (remove)
Keywords
- Migration (23) (remove)
Institute
- Fachgruppe Politik- & Verwaltungswissenschaft (6)
- Historisches Institut (3)
- Institut für Biochemie und Biologie (2)
- Sozialwissenschaften (2)
- Department Erziehungswissenschaft (1)
- Department Sport- und Gesundheitswissenschaften (1)
- Department für Inklusionspädagogik (1)
- Institut für Ernährungswissenschaft (1)
- Institut für Geowissenschaften (1)
- Institut für Germanistik (1)
In response to mounting evidence on the dangers of irregular migration from Africa to Europe, the number of information campaigns which aim to raise awareness about the potential risks has rapidly increased. Governments, international organizations and civil society organizations implement a variety of campaigns to counter the spread of misinformation accelerated by smuggling and trafficking networks. The evidence on the effects of such information interventions on potential migrants remains limited and largely anecdotal. More generally, the role of risk perceptions in the decision-making process of potential irregular migrants is rarely explicitly tested, despite the fact that the concept of risk pervades conventional migration models, particularly in the field of economics. We address this gap by assessing the effects of a peer-to-peer information intervention on the perceptions, knowledge and intentions of potential migrants in Dakar, Senegal, using a randomized controlled trial design. The results show that - three months after the intervention - peer-to-peer information events increase potential migrants' subjective information levels, raise risk awareness, and reduce intentions to migrate irregularly. We find no substantial effects on factual migration knowledge. We discuss how the effects may be driven by the trust and identification-enhancing nature of peer-to-peer communication. <br /> (c) 2021 Elsevier Ltd. All rights reserved.
Measuring migration 2.0
(2021)
The interest in human migration is at its all-time high, yet data to measure migration is notoriously limited. “Big data” or “digital trace data” have emerged as new sources of migration measurement complementing ‘traditional’ census, administrative and survey data. This paper reviews the strengths and weaknesses of eight novel, digital data sources along five domains: reliability, validity, scope, access and ethics. The review highlights the opportunities for migration scholars but also stresses the ethical and empirical challenges. This review intends to be of service to researchers and policy analysts alike and help them navigate this new and increasingly complex field.
One of the tremendous discoveries by the Cassini spacecraft has been the detection of propeller structures in Saturn's A ring. Although the generating moonlet is too small to be resolved by the cameras aboard Cassini, its produced density structure within the rings, caused by its gravity can be well observed. The largest observed propeller is called Blériot and has an azimuthal extent over several thousand kilometers. Thanks to its large size, Blériot could be identified in different images over a time span of over 10 years, allowing the reconstruction of its orbital evolution. It turns out that Blériot deviates considerably from its expected Keplerian orbit in azimuthal direction by several thousand kilometers. This excess motion can be well reconstructed by a superposition of three harmonics, and therefore resembles the typical fingerprint of a resonantly perturbed body. This PhD thesis is directed to the excess motion of Blériot. Resonant perturbations are a known for some of the outer satellites of Saturn. Thus, in the first part of this thesis, we seek for suiting resonance candidates nearby the propeller, which might explain the observed periods and amplitudes. In numeric simulations, we show that indeed resonances by Prometheus, Pandora and Mimas can explain the libration periods in good agreement, but not the amplitudes. The amplitude problem is solved by the introduction of a propeller-moonlet interaction model, where we assume a broken symmetry of the propeller by a small displacement of the moonlet. This results in a librating motion the moonlet around the propeller's symmetry center due to the non-vanishing accelerations. The retardation of the reaction of the propeller structure to the motion of the moonlet causes the propeller to become asymmetric. Hydrodynamic simulations to test our analytical model confirm our predictions. In the second part of this thesis, we consider a stochastic migration of the moonlet, which is an alternative hypothesis to explain the observed excess motion of Blériot. The mean-longitude is a time-integrated quantity and thus introduces a correlation between the independent kicks of a random walk, smoothing the noise and thus makes the residual look similar to the observed one for Blériot. We apply a diagonalization test to decorrelated the observed residuals for the propellers Blériot and Earhart and the ring-moon Daphnis. It turns out that the decorrelated distributions do not strictly follow the expected Gaussian distribution. The decorrelation method fails to distinguish a correlated random walk from a noisy libration and thus we provide an alternative study. Assuming the three-harmonic fit to be a valid representation of the excess motion for Blériot, independently from its origin, we test the likelihood that this excess motion can be created by a random walk. It turns out that a non-correlated and correlated random walk is unlikely to explain the observed excess motion.
Großstädte sind in den letzten Jahrzehnten einem massiven wirtschaftlichen und gesellschaftlichen Wandel ausgesetzt, der die städtische Sozialstruktur einmal mehr entscheidend veränderte. Basierend auf Erkenntnissen der Stadtsoziologie sowie der Arbeitsmarkt- und Migrationsforschung untersucht der vorliegende Beitrag diese Entwicklung am Beispiel Wiens. Dabei wird insbesondere der These einer zunehmenden sozialen Polarisierung in Städten nachgegangen. Es zeigt sich, dass auch in Wien die Mittelschichten im letzten Vierteljahrhundert geschrumpft sind. Ergebnisse aus multinomialen logistischen Regressionsmodellen und Dekompositionsanalysen weisen zudem darauf hin, dass Veränderungen am Arbeitsmarkt (z. B. zunehmende Verbreitung von Teilzeit) und in der Bevölkerungszusammensetzung (z. B. Herkunft von Zuwanderern) zu diesem Wandel beigetragen haben, während das steigende Bildungsniveau der Stadtbevölkerung ein noch stärkeres Schrumpfen der Mittelschicht verhindert hat.
Organizing immigration
(2020)
Immigration constitutes a dynamic policy field with – often quite unpredictable – dynamics. This is based on immigration constituting a ‘wicked problem’ meaning that it is characterized by uncertainty, ambiguity and complexity. Due to the dynamics in the policy field, expectations towards public administrations often change. Following neo-institutionalist theory, public administrations depend on meeting the expectations in the organizational field in order to maintain legitimacy as the basis for, e.g., resources and compliance of stakeholders. With the dynamics in the policy field, expectations might change and public administrations consequently need to adapt in order to maintain or repair the then threatened legitimacy. If their organizational legitimacy is threatened by a perception of structures and processes being inadequate for changed expectations, an ‘institutional crisis’ unfolds. However, we know little about ministerial bureaucracies’ structural reactions to such crucial momentums and how this effects the quest for coordination within policy-making. Overall, the dissertation thus links to both policy analysis and public administration research and consists of five publications. It asks: How do structures in ministerial bureaucracies change in the context of institutional crises? And what effect do these changes have on ministerial coordination? The dissertation hereby focusses on the above described dynamic policy field of immigration in Germany in the period from 2005 to 2017 and pursues three objectives: 1) to identify the context and impulse for changes in the structures of ministerial bureaucracies, 2) to describe respective changes with regard to their organizational structures, and 3) to identify their effect on coordination. It hereby compares and contrasts institutional crises by incremental change and shock as well as changes and effects at federal and Länder level which allows a comprehensive answer to both of the research questions. Theoretically, the dissertation follows neo-institutionalist theory with a particular focus on changes in organizational structures, coordination and crisis management. Methodologically, it follows a comparative design. Each article (except for the literature review), focusses on ministerial bureaucracies at one governmental level (federal or Länder) and on an institutional crisis induced by either an incremental process or a shock. Thus, responses and effects can be compared and contrasted across impulses for institutional crises and governmental levels. Overall, the dissertation follows a mixed methods approach with a majority of qualitative single and small-n case studies based on document analysis and semi-structured interviews. Additionally, two articles use quantitative methods as they best suited the respective research question. The rather explorative nature of these two articles however fits to the overall interpretivist approach of the dissertation. Overall, the dissertation’s core argument is: Within the investigation period, varying dynamics and thus impulses for institutional crises took place in the German policy field of immigration. Respectively, expectations by stakeholders on how the politico-administrative system should address the policy problem changed. Ministerial administrations at both the federal and Länder level adapted to these expectations in order to maintain, or regain respectively, organizational legitimacy. The administration hereby referred to well-known recipes of structural changes. Institutional crises do not constitute fields of experimentation. The new structures had an immediate effect on ministerial coordination, with respect to both the horizontal and vertical dimension. Yet, they did not mean a comprehensive change of the system in place. The dissertation thus challenges the idea of the toppling effect of crises and rather shows that adaptability and persistence of public administrations constitute two sides of the same coin.
The interaction between endothelial cells and pericytes is crucial for the stabilization of newly formed vessels in angiogenesis. The comprehension of the mechanisms regulating peiicyte recruitment might open therapeutical perspectives on vascular-related pathologies. Sphingosine 1phosphate (SIP) is a bioactive sphingolipid that derives from sphingomyelin catabolism and regulates biological functions in cell survival, proliferation, and differentiation. In this study, we aimed to identify the role of SIP axis in the intercellular communication between human mesenchymal progenitor mesoangioblasts (MAB) and endothelial cells (human microvascular endothelial cells (HMVEC)) in the formation of capillary-like structures. We demonstrated that the SIP biosynthetic pathway brought about by sphingosine kinases (SK) SKI and SK2 as well as spinster homolog 2 (SPNS2) transporter in H-MVEC is crucial for MAB migration measured by Boyden chambers and for the formation and stabilization of capillary-like structures in a 3D Matrigel culture. Moreover, the conditioned medium (CM) harvested from HMVEC, where SKI, 5K2, and SPNS2 were down-regulated, exerted a significantly diminished effect on MAB capillary morphogenesis and migration. Notably, we demonstrated that S I Pi and Si p3 receptors were positively involved in CM-induced capillary-like formation and migration, while S I P2 exerted a negative role on CM-induced migratory action of MAB. Finally, SK inhibition as well as MAB SlPi and S1P3 down-regulation impaired HMVEC-MAB cross-talk significantly reducing in vivo angiogenesis evaluated by Matrigel plug assay. These findings individuate novel targets for the employment of MAB in vascular-related pathologic conditions.
Armed conflicts trigger region-specific mechanisms that affect land use change. Deforestation is presented as one of the most common negative environmental impacts resulting from armed conflicts, with relevant consequences in terms of greenhouse gas emissions and loss of ecosystem services. However, the impact of armed conflict on forests is complex and may simultaneously lead to positive and negative environmental outcomes, i.e. forest regrowth and deforestation, in different regions even within a country. We investigate the impact that armed conflict exerted over forest dynamics at different spatial scales in Colombia and for the global tropics during the period 1992–2015. Through the analysis of its internally displaced population (departures) our results suggest that, albeit finding forest regrowth in some municipalities, the Colombian conflict predominantly exerted a negative impact on its forests. A further examination of georeferenced fighting locations in Colombia and across the globe shows that conflict areas were 8 and 4 times more likely to undergo deforestation, respectively, in the following years in relation to average deforestation rates. This study represents a municipality level, long-term spatial analysis of the diverging effects the Colombian conflict exerted over its forest dynamics over two distinct periods of increasing and decreasing conflict intensity. Moreover, it presents the first quantified estimate of conflict's negative impact on forest ecosystems across the globe. The relationship between armed conflict and land use change is of global relevance given the recent increase of armed conflicts across the world and the importance of a possible exacerbation of armed conflicts and migration as climate change impacts increase.
Poverty and social exclusion are closely related to an increased risk for the deterioration of mental health. In 2018 approximately 19% of the German population were threatened by poverty and the associated social ostracization. Migrant groups in particular often show an increased risk for poverty and are often exposed to multiple socioeconomic stress factors depending on the context of migration, pre-migration and post-migration social factors. Numerous studies have shown that societal exclusion, precarious living conditions and the residential environment negatively affect mental health beyond the effects of pre-migration risk factors. This article provides a review and discussion on the relationship between mental health, poverty and related constructs, such as social cohesion, social capital and social exclusion in general as well as in specific risk groups, such as migrant and refugee populations.
Being perceived as a foreigner regardless of one's generational status, citizenship, or self-identification is called foreigner objectification. This is a form of identity denial and is linked to psychological distress. To test how foreigner objectification could be measured in Europe, we assessed whether the Foreigner Objectification Scale demonstrated reliability and validity with German adolescents. The sample included 806 9th graders from 17 high schools. The results showed that the scale demonstrates good reliability, scalar measurement invariance across gender and citizenship status, and partial scalar measurement invariance across family heritage, generational status, and cultural self-identification. Adolescents who scored higher on the scale also reported greater school behavioral disengagement, lower life satisfaction, and stronger ethnic identity. Our findings suggest that the scale is psychometrically sound and is linked in theoretically consistent ways to adjustment and ethnic identity. We conclude that this scale offers another way to capture subtle discrimination experiences that add to a more comprehensive understanding of discrimination and the related implications in Europe.