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The changing views on the evolutionary relationships of extant Salamandridae (Amphibia: Urodela)
(2018)
The phylogenetic relationships among members of the family Salamandridae have been repeatedly investigated over the last 90 years, with changing character and taxon sampling. We review the changing composition and the phylogenetic position of salamandrid genera and species groups and add a new phylogeny based exclusively on sequences of nuclear genes. Salamandrina often changed its position depending on the characters used. It was included several times in a clade together with the primitive newts (Echinotriton, Pleurodeles, Tylototriton) due to their seemingly ancestral morphology. The latter were often inferred as a monophyletic clade. Respective monophyly was almost consistently established in all molecular studies for true salamanders (Chioglossa, Lyciasalamandra, Mertensiella, Salamandra), modern Asian newts (Cynops, Laotriton, Pachytriton, Paramesotriton) and modern New World newts (Notophthalmus, Taricha). Reciprocal non-monophyly has been established through molecular studies for the European mountain newts (Calotriton, Euproctus) and the modern European newts (Ichthyosaura, Lissotriton, Neurergus, Ommatotriton, Triturus) since Calotriton was identified as the sister lineage of Triturus. In pre-molecular studies, their respective monophyly had almost always been assumed, mainly because a complex courtship behaviour shared by their respective members. Our nuclear tree is nearly identical to a mito-genomic tree, with all but one node being highly supported. The major difference concerns the position of Calotriton, which is no longer nested within the modern European newts. This has implications for the evolution of courtship behaviour of European newts. Within modern European newts, Ichthyosaura and Lissotriton changed their position compared to the mito-genomic tree. Previous molecular trees based on seemingly large nuclear data sets, but analysed together with mitochondrial data, did not reveal monophyly of modern European newts since taxon sampling and nuclear gene coverage was too poor to obtain conclusive results. We therefore conclude that mitochondrial and nuclear data should be analysed on their own.
Phylogeographic analyses point to long-term survival on the spot in micro-endemic Lycian salamanders
(2020)
Lycian salamanders (genus Lyciasalamandra) constitute an exceptional case of microendemism of an amphibian species on the Asian Minor mainland. These viviparous salamanders are confined to karstic limestone formations along the southern Anatolian coast and some islands. We here study the genetic differentiation within and among 118 populations of all seven Lyciasalamandra species across the entire genus’ distribution. Based on circa 900 base pairs of fragments of the mitochondrial 16SrDNA and ATPase genes, we analysed the spatial haplotype distribution as well as the genetic structure and demographic history of populations. We used 253 geo-referenced populations and CHELSA climate data to infer species distribution models which we projected on climatic conditions of the Last Glacial Maximum (LGM). Within all but one species, distinct phyloclades were identified, which only in parts matched current taxonomy. Most haplotypes (78%) were private to single populations. Sometimes population genetic parameters showed contradicting results, although in several cases they indicated recent population expansion of phyloclades. Climatic suitability of localities currently inhabited by salamanders was significantly lower during the LGM compared to recent climate. All data indicated a strong degree of isolation among Lyciasalamandra populations, even within phyloclades. Given the sometimes high degree of haplotype differentiation between adjacent populations, they must have survived periods of deteriorated climates during the Quaternary on the spot. However, the alternative explanation of male biased dispersal combined with a pronounced female philopatry can only be excluded if independent nuclear data confirm this result.
Advances in eye tracking technology have enabled the development of interactive experimental setups to study social attention. Since these setups differ substantially from the eye tracker manufacturer’s test conditions, validation is essential with regard to the quality of gaze data and other factors potentially threatening the validity of this signal. In this study, we evaluated the impact of accuracy and areas of interest (AOIs) size on the classification of simulated gaze (fixation) data. We defined AOIs of different sizes using the Limited-Radius Voronoi-Tessellation (LRVT) method, and simulated gaze data for facial target points with varying accuracy. As hypothesized, we found that accuracy and AOI size had strong effects on gaze classification. In addition, these effects were not independent and differed in falsely classified gaze inside AOIs (Type I errors; false alarms) and falsely classified gaze outside the predefined AOIs (Type II errors; misses). Our results indicate that smaller AOIs generally minimize false classifications as long as accuracy is good enough. For studies with lower accuracy, Type II errors can still be compensated to some extent by using larger AOIs, but at the cost of more probable Type I errors. Proper estimation of accuracy is therefore essential for making informed decisions regarding the size of AOIs in eye tracking research.
Evaluation of an eye tracking setup for studying visual attention in face-to-face conversations
(2021)
Many eye tracking studies use facial stimuli presented on a display to investigate attentional processing of social stimuli. To introduce a more realistic approach that allows interaction between two real people, we evaluated a new eye tracking setup in three independent studies in terms of data quality, short-term reliability and feasibility. Study 1 measured the robustness, precision and accuracy for calibration stimuli compared to a classical display-based setup. Study 2 used the identical measures with an independent study sample to compare the data quality for a photograph of a face (2D) and the face of the real person (3D). Study 3 evaluated data quality over the course of a real face-to-face conversation and examined the gaze behavior on the facial features of the conversation partner. Study 1 provides evidence that quality indices for the scene-based setup were comparable to those of a classical display-based setup. Average accuracy was better than 0.4° visual angle. Study 2 demonstrates that eye tracking quality is sufficient for 3D stimuli and robust against short interruptions without re-calibration. Study 3 confirms the long-term stability of tracking accuracy during a face-to-face interaction and demonstrates typical gaze patterns for facial features. Thus, the eye tracking setup presented here seems feasible for studying gaze behavior in dyadic face-to-face interactions. Eye tracking data obtained with this setup achieves an accuracy that is sufficient for investigating behavior such as eye contact in social interactions in a range of populations including clinical conditions, such as autism spectrum and social phobia.
For decades, academics and practitioners aim to understand whether and how (economic) events affect firm value. Optimally, these events occur exogenously, i.e. suddenly and unexpectedly, so that an accurate evaluation of the effects on firm value can be conducted. However, recent studies show that even the evaluation of exogenous events is often prone to many challenges that can lead to diverse interpretations, resulting in heated debates. Recently, there have been intense debates in particular on the impact of takeover defenses and of Covid-19 on firm value. The announcements of takeover defenses and the propagation of Covid-19 are exogenous events that occur worldwide and are economically important, but have been insufficiently examined. By answering open research questions, this dissertation aims to provide a greater understanding about the heterogeneous effects that exogenous events such as the announcements of takeover defenses and the propagation of Covid-19 have on firm value. In addition, this dissertation analyzes the influence of certain firm characteristics on the effects of these two exogenous events and identifies influencing factors that explain contradictory results in the existing literature and thus can reconcile different views.
This paper describes the concept of the hyperspectral Earth-observing thermal infrared (TIR) satellite mission HiTeSEM (High-resolution Temperature and Spectral Emissivity Mapping). The scientific goal is to measure specific key variables from the biosphere, hydrosphere, pedosphere, and geosphere related to two global problems of significant societal relevance: food security and human health. The key variables comprise land and sea surface radiation temperature and emissivity, surface moisture, thermal inertia, evapotranspiration, soil minerals and grain size components, soil organic carbon, plant physiological variables, and heat fluxes. The retrieval of this information requires a TIR imaging system with adequate spatial and spectral resolutions and with day-night following observation capability. Another challenge is the monitoring of temporally high dynamic features like energy fluxes, which require adequate revisit time. The suggested solution is a sensor pointing concept to allow high revisit times for selected target regions (1"5 days at off-nadir). At the same time, global observations in the nadir direction are guaranteed with a lower temporal repeat cycle (>1 month). To account for the demand of a high spatial resolution for complex targets, it is suggested to combine in one optic (1) a hyperspectral TIR system with ~75 bands at 7.2"12.5 -µm (instrument NEDT 0.05 K"0.1 K) and a ground sampling distance (GSD) of 60 m, and (2) a panchromatic high-resolution TIR-imager with two channels (8.0"10.25 -µm and 10.25"12.5 -µm) and a GSD of 20 m. The identified science case requires a good correlation of the instrument orbit with Sentinel-2 (maximum delay of 1"3 days) to combine data from the visible and near infrared (VNIR), the shortwave infrared (SWIR) and TIR spectral regions and to refine parameter retrieval.
The rate and range of ongoing changes in social and ecological systems and particularly the global environmental degradation illustrates the need of holistic and sustainable approaches for the governance of natural resources to ensure their well-functioning for future generations (Rockström et al. 2009). The narrative of common pool resources system such as SES of small-scale fisheries, reports world-wide of stock collapse, environmental degradation and overexploitation (Cinner et al. 2013). In order to understand the complexity of system interactions in those resource systems, the consideration of local scale specific phenomena is of great relevance (Ostrom 2007b). The focus of this thesis consequently is the social-ecological system of a small scale fishery in a heavily urbanised coastal wetland on the fringes of Ghana ́s capital Accra. With the theoretical foundation of the social-ecological system (SES) theory (Folke et al. 2004; Berkes et al. 2003; G. S. Cumming 2011) and the social-ecological system framework (SESF) by Ostrom (2007a) and McGinnis & Ostrom (2014) as analytical tool, the study ex- amines the role of the fishers as focal actor group and the governance system based on traditional ecological knowledge (TEK) (Berkes et al. 2003). While the common narrative of system collapse is partly confirmed for the focal system, also contradicting findings about the diversity of the actor group, their sustainable and responsible exploitation of the deltas resources have been found, that rather illustrate the fishers as potential cooperation partners for the development of sustainable governance strategies (see Hollup 2000) than simply as bur- den to the system. However, the results also show that in order to achieve sustainable outcomes in the focal SES, so far unsuccessful top-down governance efforts have to work cooperatively with the fishers to challenge the multiple threats to the system from external perturbation and internal changes, in the long run.
Today obesity has been recognized as a disease. Evidence suggests that obesity often has Genetic, environmental, psychological and other factors. Growing evidence points to heredity as a strong determining factor of obesity. The characterization of uncoupling proteins (UCP) represents a major breakthrough of genetic factors towards understanding the molecular basis for energy expenditure and therefore likely to have important implication for the cause and treatment of human obesity. UCPs as mitochondrial anion carriers which creates a pathway that allows dissipation of the proton electrochemical gradient therefore which when deregulated are key risk factors in the development of obesity and other eating disorders. In order to better understand the roles of both UCP2 and UCP3 which considered as prime candidate genes involved in the pathogenesis of obesity, this study elucidate (1) Genomic organization: The human UCP2 (3) gene spans over 8.7 kb (7.5 kb) distributed on 8 (7) exons. Three UCP genes may have evolved from a common ancestor or are the result from gene duplication events. Two mRNA transcripts are generated from hUCP3 gene, the long and short form of hUCP3 is differing by the presence or absence of 37 amino acid residues at the C-terminus. (2) Mutational analysis revealed a mutation in exon 4 of hUCP2 resulting in the substitution of an alanine by a valine at codon 55 and an insertion polymorphism in exon 8 consisted of a 45 bp repeat located 150 bp downstream of the stop codon in the 3'-UTR. The allele frequencies of both polymorphisms were not significantly elevated in a subgroup of children characterized by low Resting Metabolic Rates (RMR). (3) Promoter Analysis showed that the promoter region of hUCP2 lacks a classical TATA or CAAT box. Functional characterization of hUCP2 promoter showed that minimal promoter activity was observed within 65 bp upstream of the transcriptional start site. 75 bp further upstream a strong cis-acting regulatory element was identified which significantly enhanced basal promoter activity. The regulation of human UCP2 gene expression involves complex interactions among positive and negative regulatory elements. the 5"-flanking region of the hUCP3 gene were characterized in which contains both TATA and CAAT boxes as well as consensus motifs for PPRE, TRE, CRE and muscle-specific MyoD and MEF2 sites. Functional characterization identified a cis-acting negative regulatory element between - 2983 and -982 while the region between -982 and -284 showed greatly increased basal promoter activity suggesting the presence of a strong enhancer element. Promoter activity was particularly enhanced in the murine skeletal muscle cell line C2C12 reflecting the tissue-selective expression pattern of UCP3.
Cortisol exhibits typical ultradian and circadian rhythm and disturbances in its secretory pattern have been described in stress-related pathology. The aim of this thesis was to dissect the underlying structure of cortisol pulsatility and to develop tools to investigate the effects of this pulsatility on immune cell trafficking and the responsiveness of the neuroendocrine system and GR target genes to stress. Deconvolution modeling was set up as a tool for investigation of the pulsatile secretion underlying the ultradian cortisol rhythm. This further allowed us to investigate the role of the single cortisol pulses on the immune cell trafficking and the role of induced cortisol pulses on the kinetics of expression of GR target genes. The development of these three tools, would allow to induce and investigate in future the significance of single cortisol pulses for health and disease.
Designing a Randomized Trial with an Age Simulation Suit—Representing People with Health Impairments
(2020)
Due to demographic change, there is an increasing demand for professional care services, whereby this demand cannot be met by available caregivers. To enable adequate care by relieving informal and formal care, the independence of people with chronic diseases has to be preserved for as long as possible. Assistance approaches can be used that support promoting physical activity, which is a main predictor of independence. One challenge is to design and test such approaches without affecting the people in focus. In this paper, we propose a design for a randomized trial to enable the use of an age simulation suit to generate reference data of people with health impairments with young and healthy participants. Therefore, we focus on situations of increased physical activity.