Philipp University of Marburg

Why are there so many species in the tropics? Ecologists have no definite answer to this question. While theories explaining biodiversity maintenance have arisen in the past few decades, testing them with empirical data in tropical rainforests can be challenging because of the slow dynamics of tree communities. By focusing on bryophytes and lichens living on leaves - ‘epiphylls’ - EPIDYN aims to test the two main types of biodiversity theories in an ecological system of much faster dynamics and easier replication than tropical rain forests, while maintaining similarly high levels of biodiversity. To this end, leaves will be monitored in a tropical rainforest in Panama under different light and moisture conditions - the most limiting factors for bryophytes and lichens in tropical rainforests. In so doing, EPIDYN will be the first study to explicitly address species interactions and community dynamics among epiphyll species within leaves. Theoretical models of biodiversity maintenance in plant communities range from ‘neutral theories’ to niche-based models. In both types of models, species interactions play an important role, but the predicted outcomes differ. For example, in vegetation succession, the neutral ‘priority effect’ predicts that any first species to arrive in a new habitat will dominate, while models favoring ecological niches consider a range of species interactions, both negative (competition, allopathy) and positive (facilitation). In this project I aim to determine: (1) which are the most appropriate theoretical models to describe species interactions and successional dynamics in epiphyll communities, and (2) how the relative applicability of each model depends on environmental conditions. Using state-of-the-art spatial pattern analysis as well as innovative model testing, EPIDYN will provide an original approach to testing fundamental ecological theory in an abundant but little-researched miniature-scale ecosystem.

Human visual perception is one of the best-studied areas of research on the human mind. However, 99% of that research is concentrated on the central region making up less than 1% of our visual field. This is the region that gets mapped onto the fovea, where vision is best. However, information from the peripheral parts of a scene is highly important. Mediated by attention and eye movements, it is essential for guiding us through our environment. In the brain, the foveal and peripheral parts of the visual field undergo vastly different processing regimes. Since objects normally do not change their appearance, whether we view them foveally or peripherally, our visual system must integrate and calibrate peripheral information before an eye movement with foveal information after an eye movement. We are planning to address these processes in four series of experiments. First, we will study the perception of basic visual features, such as orientation, numerosity and colour across the visual field and their integration in peripheral and foveal vision across eye movements. Second, we will investigate how this integration is supported by attention and memory resources. Third, since the integration requires learning and plasticity, we will track changes across the life span and study how healthy subjects can learn to compensate for artificial changes of peripheral and foveal vision. And fourth, we will explore whether we can manipulate the integration process for the optimal guidance of eye movements in complex natural search tasks. The project will provide insights how the brain achieves a stable and homogeneous representation of the visual environment despite the ever changing sensory input and the inhomogeneity of processing across the visual field. We will reveal the basic learning mechanisms that allow a continuous calibration of peripheral and foveal vision, and that could be used in the long run for behavioural training of patients suffering from vision impairments.

The primary goal of this Fellowship, entitled “SEmiconductor disk Lasers for EffiCient Terahertz generation” (SELECT), is to train a talented researcher through a research project focused on the development of high-performance laser sources based on semiconductor disk lasers and novel periodically poled ferroelectric and semiconductor crystals that can offer an access to new wavelengths not covered by available gain media, particularly in the THz spectral region, which are desired for THz spectroscopy, Biomedical imaging, and Safety and Security applications. The novel high-performance vertical-external-cavity surface-emitting-laser, with remarkable output parameters, will be used as a source of ultra-efficient THz emission in the 0.8-3THz spectral window based on difference frequency generation in advanced quasi-phase-matched crystals. The success of the interdisciplinary project will lead to a number of multidisciplinary disruptive innovations in Photonics with significant scientific, technical, economic and social impact, from spectroscopy and biomedical imaging to security screening and quality control. The Fellow - Dr. Ksenia Fedorova - will be trained in the fast growing field of science, technology and industrial applications of semiconductor lasers and THz technology, receiving access to a unique training experience at the host – Philipps- Universität Marburg, and at academic and industrial secondments: Aston University, Innolume GmbH, M-Squared Lasers Ltd. The project will enable the Fellow to be a rare asset to European research; she will gain a set of multidisciplinary professional skills in both theoretical and practical fields, starting from the laser system design and fabrication and finishing with implementing the final product into real industrial applications. The SELECT outputs will be relevant to the EU Photonics industry through offering new efficient compact THz lasers, which will also contribute to the enhancement of EU scientific excellence.