Noise As a Factor of Green Areas Soundscape Creation

The research subject presented in the paper is acoustic perception, the perception  of a sound landscape by a  human.  The  paper  aim  was  formulated  -  knowing  the sources of noise based on the subjective assessment of recipients allows for sustainable management of green areas (city parks). The need to shape a harmonious landscape may contribute to finding a new function and attractive form for the studied areas. Research carried out for selected city parks in Bydgoszcz (Poland) concerns the registration of responses of people assessing the sound landscape (subjective approach). Completed studies allow ”translating” subjective assessments into meaningful values using fuzzy cognitive maps. The scenarios completed show the possibility of using tools supporting the decision-making process in urban planning of city parks in relation to existing acoustic conditions. Keywords: Noise, Soundscape, Green areas, Urban planning, Environmen

The Impact of Heterogenous Cell Populations on Impedance-Based Cell Analysis

Many in vitro studies for drug development are based on population-averaging measurement techniques without giving information about cell-to-cell variability within the cell ensembles under study. However, such heterogeneities in cell cultures are omnipresent and can arise by several causes, like spontaneous genetic mutations, different metabolic situations or different cell cycle states of individual cells. Moreover, microenvironmental conditions, like cell crowding, might force cell ensembles to form subpopulations with distinct characteristics. Therefore, single phenotypically different subpopulations may be overseen or averaged responses across different subpopulations might not reflect the majority of the cells, leading to misinterpretations of data – one possible reason for the high failure rate in clinical trials. This thesis addressed the fundamental question of how cell-to-cell variability in populations influence the signal of population-based assays by using three different approaches. The first project addressed the impact of evenly distributed heterogeneities within cell populations, introduced by mixing a cell line expressing a certain G protein-coupled receptor (GPCR) with a cell line not expressing this receptor type, on the impedance-based cell analysis. The second project focused on the development of an impedance-based assay for the future purpose of spatiotemporally introducing heterogeneities in an isogenic cell population, expressing a certain GPCR, by switching an appropriate, photochromic ligand by illumination. The third project addressed the quantification of the impact of heterogeneities within cell populations on the impedance-based cell analysis in a theoretical manner. The first project focused on the impact of cell-to-cell variability on the population-based impedance signal by mixing cell lines in different ratios prior to the seeding onto the co-planar gold electrodes. The evenly distributed heterogeneities in the resulting cell populations were generated by co-culturing two cell lines with one of them expressing a GPCR predominantly coupled to one of the three main canonical G-protein pathways (Gq, Gs, Gi/o). A protocol was established to obtain co-cultures with distinct cell ratios resulting in well-defined areal receptor densities (ARD) as verified by supported microscopic staining studies. The stimulation of cell ensembles with varying ARD by the GPCR's endogenous ligands was analyzed in detail by wholistic impedance-based cell assays. Efficacies and potencies, which describe the maximal agonist effect and the activity of a drug, were compared to those of the pure and original cell lines. It was shown that both parameters were dependent on the ARD and the coupled signaling cascades in distinct ways: for the Gq pathway, efficacy decreased non-linearly with decreasing ARD, while the Gs- and Gi/o-pathways exhibited an almost linear dependency of efficacy on the ARD. The potencies observed for the Gq- and Gi/o-coupled signaling pathway decreased with decreasing ARD, while the potency of the Gs-pathway was almost independent of the ARD. Simple simulations indicated that underlying communication processes between stimulated and non-stimulated cells within the populations under study may be responsible for these trends. Additionally, two proximal assay techniques were used to assist the interpretation of impedance analysis and to assign the impact of the ARD on the signal to a certain part of the signaling cascade. The radioligand competition binding assay confirmed the correct co-culturing strategy for such heterogeneous cell populations and confirmed the corresponding potency to be independent of the population composition. Population-based Ca2+ imaging highlighted the impact of altering the ARD on second messenger mobilization. Again, the ARD did not affect the potency, but the analysis of the response on a single-cell level proposed cell communication as a potential mechanism explaining the dependency of impedance on ARD. Moreover, the stimulation of a co-culture, consisting of two GPCR-expressing cell lines, was analyzed impedimetrically. The outcomes indicated that the potency dependency on the ARD was caused by the simultaneous activation of two different signaling pathways. The obtained data confirmed that the impact of artificially introduced heterogeneities in the cell population under study on the obtained impedance signal was indeed significant. Nevertheless, it remains elusive, whether these results can be translated to other cell lines or other GPCRs. This project addressed the fundamental question of areal heterogeneities influencing the impedance signal. However, further studies on cell ensembles with different compositions and other measurement techniques have to be carried out to obtain a broader picture of such impacts on population-based measurements and its significance for the drug development process. In the second project of this thesis, an assay was developed for the future purpose of introducing cell-to-cell variability within isogenic cell populations by spatiotemporal illumination of photochromic GPCR-ligands, which can be toggled between their bioactive and -inactive isomer. Thus, it was required to establish a protocol to active in situ such a ligand by online irradiation with light and to monitor the cell responses in a time-resolved manner. The wholistic impedance-based cell assay was appropriate to monitor the in situ toggling of a model photoswitchable ligand for a Gq-coupled receptor. To accomplish the superordinate goal, it will be necessary to establish a measurement setup, which is capable of spatiotemporal illumination of the cell culture, so that a small subpopulation can be stimulated in a spatiotemporally well-defined manner after the systemic addition of the bioinactive species of a photoswitchable ligand. The third part of this thesis addressed the impact of heterogeneous cell populations on the impedance readout by theoretical means. For this purpose, a MATLAB-based algorithm was developed, capable of simulating different cell types following the electric cell-substrate impedance sensing (ECIS) model. In contrast to the conventional mode, which assumes global cell-related parameters (α for the cell-substrate contacts, Rb for the cell-cell contacts, Cm for the cell membrane capacitances) for the whole population, the new approach emulated cell populations by cell-related parameters, each showing a Gaussian distribution with a mean and a deviation value. After successful validation of the underlying algorithm, discrepancies from the ECIS model using global parameters were found for such populations with heterogeneous cell-related parameters for three distinct cell types, emulating leaky, moderately tight, and tight cells. Especially the deviation of the Gaussian-distributed parameters α and Rb had a big impact on the spectra. In direct comparison to the reference, which was a homogenous cell population with global parameter values being equal to the mean values of the Gaussian distribution, a systematical misestimation could be found for α (up to 110 % of the reference value) and underestimation for Rb (down to 78 % of the reference value) when the deviation values were set to 30 % of the mean values. In contrast, Cm was found to be very robust for deviations up to 30 % (100 % of the reference value). In summary, the thesis has demonstrated in an experimental and theoretical manner that cell-to-cell variability has indeed major impacts on the population-based impedance signal, having the potential to misdirect data interpretation. These can affect fundamental as well as pharmacological research. Thus, it is crucial to address such heterogeneities within cell populations in future studies using population- as well as single-cell-based assay techniques

Phenology is the dominant control of methane emissions in a tropical non-forested wetland

Tropical wetlands are a significant source of atmospheric methane (CH4), but their importance to the global CH4 budget is uncertain due to a paucity of direct observations. Net wetland emissions result from complex interactions and co-variation between microbial production and oxidation in the soil, and transport to the atmosphere. Here we show that phenology is the overarching control of net CH4 emissions to the atmosphere from a permanent, vegetated tropical swamp in the Okavango Delta, Botswana, and we find that vegetative processes modulate net CH4 emissions at sub-daily to inter-annual timescales. Without considering the role played by papyrus on regulating the efflux of CH4 to the atmosphere, the annual budget for the entire Okavango Delta, would be under- or over-estimated by a factor of two. Our measurements demonstrate the importance of including vegetative processes such as phenological cycles into wetlands emission budgets of CH4

From sink to source: high inter-annual variability in the carbon budget of a southern African wetland

We report on three years of continuous monitoring of carbon dioxide (CO2) and methane (CH4) emissions in two contrasting wetland areas of the Okavango Delta, Botswana: a perennial swamp and a seasonal floodplain. The hydrographic zones of the Okavango Delta possess distinct attributes (e.g. vegetation zonation, hydrology) which dictate their respective greenhouse gas (GHG) temporal emission patterns and magnitude. The perennial swamp was a net source of carbon (expressed in CO2-eq units), while the seasonal swamp was a sink in 2018. Despite differences in vegetation types and lifecycles, the net CO2 uptake was comparable at the two sites studied in 2018/2020 (−894.2 ± 127.4 g m−2 yr−1 at the perennial swamp, average of the 2018 and 2020 budgets, and −1024.5 ± 134.7 g m−2 yr−1 at the seasonal floodplain). The annual budgets of CH4 were however a factor of three larger at the permanent swamp in 2018 compared to the seasonal floodplain. Both ecosystems were sensitive to drought, which switched these sinks of atmospheric CO2 into sources in 2019. This phenomenon was particularly strong at the seasonal floodplain (net annual loss of CO2 of 1572.4 ± 158.1 g m−2), due to a sharp decrease in gross primary productivity. Similarly, drought caused CH4 emissions at the seasonal floodplain to decrease by a factor of 4 in 2019 compared to the previous year, but emissions from the perennial swamp were unaffected. Our study demonstrates that complex and divergent processes can coexist within the same landscape, and that meteorological anomalies can significantly perturb the balance of the individual terms of the GHG budget. Seasonal floodplains are particularly sensitive to drought, which exacerbate carbon losses to the atmosphere, and it is crucial to improve our understanding of the role played by such wetlands in order to better forecast how their emissions might evolve in a changing climate. Studying such hydro-ecosystems, particularly in the data-poor tropics, and how natural stressors such as drought affect them, can also inform on the potential impacts of man-made perturbations (e.g. construction of hydro-electric dams) and how these might be mitigated. Given the contrasting effects of drought on the CO2 and CH4 flux terms, it is crucial to evaluate an ecosystem's complete carbon budget instead of treating these GHGs in isolation

Geophysical analysis of an area affected by subsurface dissolution - case study of an inland salt marsh in northern Thuringia, Germany

The subsurface dissolution of soluble rocks can affect areas over a long period of time and pose a severe hazard. We show the benefits of a combined approach using P-wave and SH-wave reflection seismics, electrical resistivity tomography, transient electromagnetics, and gravimetry for a better understanding of the dissolution process. The study area, "Esperstedter Ried"in northern Thuringia, Germany, located south of the Kyffhäuser hills, is a large inland salt marsh that developed due to dissolution of soluble rocks at approximately 300 m depth. We were able to locate buried dissolution structures and zones, faults and fractures, and potential fluid pathways, aquifers, and aquitards based on seismic and electromagnetic surveys. Further improvement of the model was accomplished by analyzing gravimetry data that indicates dissolution-induced mass movement, as shown by local minima of the Bouguer anomaly for the Esperstedter Ried. Forward modeling of the gravimetry data, in combination with the seismic results, delivered a cross section through the inland salt marsh from north to south. We conclude that tectonic movements during the Tertiary, which led to the uplift of the Kyffhäuser hills and the formation of faults parallel and perpendicular to the low mountain range, were the initial trigger for subsurface dissolution. The faults and the fractured Triassic and lower Tertiary deposits serve as fluid pathways for groundwater to leach the deep Permian Zechstein deposits, since dissolution and erosional processes are more intense near faults. The artesian-confined saltwater rises towards the surface along the faults and fracture networks, and it formed the inland salt marsh over time. In the past, dissolution of the Zechstein formations formed several, now buried, sagging and collapse structures, and, since the entire region is affected by recent sinkhole development, dissolution is still ongoing. From the results of this study, we suggest that the combined geophysical investigation of areas prone to subsurface dissolution can improve the knowledge of control factors, hazardous areas, and thus local dissolution processes

An Experimental Analysis Of the Demand For Payday Loans

The payday loan industry is one of the fastest growing segments of the consumer financial services market in the United States. We design an environment similar to the one that payday loan customers face and then conduct a laboratory experiment to examine what effect, if any, the existence of payday loans has on individuals\u27 abilities to manage and to survive financial setbacks. Our primary objective is to examine whether access to payday loans improves or worsens the likelihood of financial survival in our experiment. We also test the degree to which people\u27s use of payday loans affects their ability to survive financially. We find that payday loans help the subjects to absorb expenditure shocks and therefore survive financially. However, subjects whose demand for payday loans exceeds a certain threshold level are at a greater risk than a corresponding subject in the treatment in which payday loans do not exist

A high-precision wound healing assay based on photosensitized culture substrates

Quantitative assessment of cell migration in vitro is often required in fundamental and applied research from different biomedical areas including wound repair, tumor metastasis or developmental biology. A collection of assays has been established throughout the years like the most widely used scratch assay or the so-called barrier assay. It is the principle of these assays to introduce a lesion into an otherwise confluent monolayer in order to study the migration of cells from the periphery into this artificial wound and determine the migration rate from the time necessary for wound closure. A novel assay makes use of photosensitizers doped into a polystyrene matrix. A thin layer of this composite material is coated on the bottom of regular cell culture ware showing perfect biocompatibility. When adherent cells are grown on this coating, resonant excitation of the photosensitizer induces a very local generation of 1O2, which kills the cells residing at the site of illumination. Cells outside the site of illumination are not harmed. When excitation of the photosensitizer is conducted by microscopic illumination, high-precision wounding in any size and geometry is available even in microfluidic channels. Besides proof-of-concept experiments, this study gives further insight into the mechanism of photosensitizer-mediated cell wounding

Top Quarks and Electroweak Symmetry Breaking in Little Higgs Models

`Little Higgs' models, in which the Higgs particle arises as a pseudo-Goldstone boson, have a natural mechanism of electroweak symmetry breaking associated with the large value of the top quark Yukawa coupling. The mechanism typically involves a new heavy SU(2)_{L} singlet top quark, T. We discuss the relationship of the Higgs boson and the two top quarks. We suggest experimental tests of the Little Higgs mechanism of electroweak symmetry breaking using the production and decay of the T at the Large Hadron Collider.Comment: 28 pages, 6 figures; new ST fits (Fig. 3,4

Monitoring the Reversibility of GPCR Signaling by Combining Photochromic Ligands with Label-free Impedance Analysis

G protein-coupled cell surface receptors (GPCR) trigger complex intracellular signaling cascades upon agonist binding. Classic pharmacological assays provide information about binding affinities, activation or blockade at different stages of the signaling cascade, but real time dynamics and reversibility of these processes remain often disguised. We show that combining photochromic NPY receptor ligands, which can be toggled in their receptor activation ability by irradiation with light of different wavelengths, with whole cell label-free impedance assays allows observing the cell response to receptor activation and its reversibility over time. The concept demonstrated on NPY receptors may be well applicable to many other GPCRs providing a deeper insight into the time course of intracellular signaling processes