No Tertiary relicts? A biogeographical study on the Macaronesian laurel forest species in Daucus (Apiaceae), Geranium (Geraniaceae), Gesnouinia (Urticaceae), Phyllis (Rubiaceae), Semele (Asparagaceae) and Visnea (Pentaphylacaceae)

The Macaronesian laurel forest is characterized by humidity-adapted, evergreen trees with glossy, entire and elongated leaves. Based on fossil data, this vegetation type has been regarded as a relict of Tertiary, European/Mediterranean forests since at least the middle of the 19th century. In contrast to that, more recent studies indicate that the Macaronesian laurel forest species may be much younger than previously thought, with the majority of the analyzed species dating to the Plio-/Pleistocene. Furthermore, they recovered a rather heterogeneous geographical origin, suggesting that the Mediterranean region, other Macaronesian vegetation zones as well as tropical areas have served as source areas for the corresponding species. Although previous analyses included quite characteristic taxa, e.g. all of the Macaronesian Lauraceae, only a small number (around 26%) of laurel forest genera has been studied to this day, most of them are woody. In this dissertation, the biogeography of six typical and widespread Macaronesian laurel forest genera (Daucus, Geranium, Gesnouinia, Phyllis, Semele and Visnea) is studied, covering different life-forms and ecologies. Conducting molecular phylogenetic and dating analyses as well as ancestral area estimations, a) the timeframes for the colonization of Macaronesia and the laurel forest, b) the geographical origin of the colonizers and c) the timeframes for inter-archipelago and inter-island dispersal were studied. Furthermore, the usefulness of stem ages and crown ages for inferring the colonization times is tested. Additional analyses were conducted for Gesnouinia and Visnea. In Gesnouinia, the wood anatomy was studied as the genus was considered as potentially insular woody in previous studies, which would contradict a relict status. For Visnea, fossils of the extinct V. germanica from the Miocene to Pliocene of Germany and Italy were analyzed regarding their affinity to laurel forest V. mocanera using MicroCT scans. The results obtained here provide further support for the heterogeneous origin of the Macaronesian laurel forest and indicate that stem ages should be preferred over crown ages for inferring the relict status. A relict origin of Visnea (Oligocene age) and the laurel forest taxa of Geranium (Miocene age) is very likely, whereas the situation is ambiguous in Semele and Daucus. The latter two are of Miocene age, but their phylogenetic position is poorly resolved. Laurel forest Gesnouinia and Phyllis originated within Macaronesia and are clearly no relicts from the Tertiary by their source area. Dispersal from or into the dry infra-Canarian vegetation is indicated for both genera, with the time frames differing. In Phyllis, dispersal falls into the Early Pliocene, whereas in Gesnouinia, an overlap with range-shifts associated with the Pleistocene glaciation cycles is recovered. The non-relictual trait of insular woodiness could not be unambiguously inferred for Gesnouinia. While woodiness in Gesnouinia probably is derived, it may have evolved prior to island colonization. Interarchipelago colonization between Madeira and the Canary Islands is inferred to be young in most taxa, overlapping with Pleistocene sea-level fluctuations and the timeframes recovered for species from other Macaronesian vegetation zones. The same is found for inter-island colonization within the archipelagos. For the Macaronesian laurel forest as a whole, the newly generated data as well as literature data indicate that there is likely no obvious relationship between time of colonization and life-form or time of colonization and the extant ecological niche occupied within the forest. Instead, data points towards a link between time of colonization and the main source area of the colonizers. In the humid climate of the Late Miocene, habitat conservative dispersal from the Mediterranean/Europe to newly emerged islands and habitat space created by catastrophic events seems to have predominated. In the still humid Early Pliocene, the influx from the Mediterranean/Europe decreased and the majority of colonizers originated within Macaronesia. During the Late Pliocene climatic deterioration (cooler, drier and increasing seasonal), dispersal from the Mediterranean, probably non-habitat conservatively, was prevalent. In the course of the Pleistocene (Early and Middle), climatic changes and range shifts associated with the glaciation cycles possibly promoted the arrival of a large amount of Macaronesian taxa. Pleistocene establishment is also indicated for a number of Mediterranean/European taxa, but restricted to the Early Pleistocene. Colonization events from Asia, the New World and (Eastern) Africa seem to be rare and likely occurred prior to the Pleistocene. They may have been facilitated by the lack of e.g. climatic, tectonic or marine barriers during certain periods of time

Theatre Exhibitions, Models and the Quest for Anschauung

The large-scale theatre exhibitions in Vienna (1892), Berlin (1910) and Magdeburg (1927) contained extensive displays on the history of German-language theatre. This article analyses the pedagogical and epistemological discussions about different ways of mediating theatre history that formed part of the context of the three exhibitions. Curators and scholars used the German term Anschauung to measure the transfer of knowledge in historical exhibitions, reconstruction models and historiography books. This article contributes to the recent scholarship on forms of exhibiting, collecting and archiving theatre, dance and performance. It shows that theatre became an area of focus within the culture of national and international large-scale exhibitions around 1900. This was accompanied by discussions about the appropriate medium to present the history of theatre. Informed by museum pedagogy and humanities hermeneutics, curators and scholars conceived of divergent concepts of theatre history Anschauung

Complementarities of HRM Practices - A Case for Employing Multiple Methods and Integrating Multiple Fields

We provide an overview over different literature streams that aim at explaining the origin of persistent productivity differences across organizations by variation in the use of management practices. We focus on human resource management (HRM) practices, document gaps in the literature, and show how insights from behavioral economics can inform the analysis. To this end, we develop a simple agency model illustrating how social preferences influence the design and impact of incentive schemes, investigate how auxiliary HRM practices can strengthen this interaction, and provide an overview over empirical investigations of this questions. Finally, we identify avenues for further research in this field

First High-Precision Mass Measurements at PENTATRAP on highly charged Xe and Re ions

The high-precision Penning-trap mass spectrometer Pentatrap was designed to perform mass-ratio measurements of highly charged ions with relative uncertainties of 10−11. The unique features of the Pentatrap experiment are the external ion sources providing highly charged ions, the detection systems with single-ion sensitivity and especially the stack of five Penning traps, which allows simultaneous measurements of single ions in the traps. In the scope of this thesis, the first high-precision mass measurements with a relative precision partially below δm/m ≈ 10−11 were performed. As a first benchmark test, the mass differences of five xenon isotope pairs were determined. Comparison to the literature values led to an improvement of the uncertainty of the mass differences of a factor between 4 and 1700, in agreement with literature. In order to demonstrate the accuracy of Pentatrap, the binding energy of the 37th electron in 132Xe was determined as a proof-of-principle measurement by determining the mass difference of 132Xe17+ and 132Xe18+. The agreement of the result with theory allows performing stringent tests of quantum electrodynamics using binding energies in ions with an even higher charge state in the future. Lastly, the discovery of metastable electronic states in highly charged rhe- nium and osmium ions by mass difference measurements, confirmed by theory, extends the applicability of Penning-trap mass spectrometry to tests of atomic structure theories and to the identification of long-lived excited states for a possible new generation of clocks using highly charged ions

A Review of Positive Feedback Mechanisms in Technology Markets, Regional Clusters, and Organizations

The concept of path dependence has often been criticized as vague and only narrowly applicable. Although we can find some very refined definitions of the concept, we also find a wide range of empirical phenomena being described as path-dependent. We argue that more detailed accounts of the positive feedback mechanisms that form paths can take path dependence beyond this state of being overdetermined, but under-specified. Reviewing three well-described cases of path-dependent dynamics in technology markets, regional clustering, and organizations, we define a core set of positive feedback mechanisms that constitute path dependence at different analysis levels and clarify the relationship between positive feedback and increasing returns. We show that path-dependent processes, that is, processes driven by positive feedback that veer toward rigidity or lock-in, can be (but do not have to be) found under many labels, including structural inertia, coevolution, or institutional persistence. We conclude that a precise definition of path dependence does not need to be at odds with the concept’s widespread use in understanding organizational and industrial development processes