Systematischer Review und Meta-Analysen zu Effekten selektiver Partnerwahl (Assortative Mating), mit Fokus auf Alter, Bildung und physische Aspekte

Dieser systematische Review beleuchtet das Thema Assortative Mating in den Variablen Alter, Bildung, Körpergröße, Körpergewicht und BMI. Assortative Mating kann als die nicht zufällige Partnerwahl nach Kriterien der Ähnlichkeit der Partner in diversen Merkmalen beschrieben werden und ist seit den Zeiten Charles Darwins Gegenstand der Wissenschaft (Buss, 1984a). Die Ähnlichkeiten zwischen den Paaren wurden in dieser Arbeit in Form einer Meta-Analyse berechnet und diskutiert, um Schlüsse über die Forschung von 1903 bis 2012 ziehen zu können. Es wird ein Überblick über häufig im Zusammenhang mit Assortative Mating stehende Begriffe, Erklärungsmodelle der Partnerwahl sowie Hintergründe des Forschungsinteresses gegeben. Die Anfänge der Forschung werden ab Beginn des 20. Jahrhunderts dargestellt. Forschungsberichte in den Variablen Alter, Bildung, Körpergröße, Körpergewicht und BMI werden einzeln im Überblick erläutert. Die Berechnung der meta-analytischen Ergebnisse mit dem Programm Comprehensive Meta-Analysis, 2.0. konzentriert sich auf die Korrelationen der Paare in den zu interessierenden Variablen, Effekte des Publikationsjahres und Subgruppeneffekte der Herkunft der Stichproben. Die Ergebnisse zeigen, dass in allen interessierenden Variablen ein signifikanter Zusammenhang zwischen den Partnern besteht. Diese Zusammenhänge variieren von schwachen Effekten wie für Körpergröße, Körpergewicht und BMI, über starke Effekte für Bildung bis zu sehr starken Zusammenhängen für die Variable Alter. Die Hypothese, dass diese Merkmale bei der Partnerwahl eine wichtige Rolle spielen, lässt sich somit bestätigen und entspricht den, in der Literatur vorhandenen, Forschungsergebnissen. Die Ergebnisse der Metaregressionen für das Jahr der Veröffentlichung konnten für die Variablen Bildung und BMI ebenfalls signifikante Effekte finden und einen Einfluss der Zeit der Studienpublikation beweisen. Subgruppeneffekte zeigen für die Merkmale Alter, Bildung und Körpergröße signifikante Unterschiede in der Herkunft der Paare. Auf mögliche Erklärungsansätze der gefundenen Korrelationen, Metaregressions-und Subgruppeneffekte wird in der Diskussion eingegangen. 77 Weitere Bereiche der zukünftigen Forschung können ausgereiftere Erklärungsansätze, warum sich die Partner in den beschriebenen Merkmalen ähneln, darstellen. Des Weiteren sind noch mehr Studien von Interesse, die Paare aus nicht-westlichen Ländern untersuchen, da es dazu im Vergleich noch wenige Ergebnisse gibt und es wahrscheinlich ist, dass es zu Abweichungen im Vergleich zu den Industrienationen kommen könnte. Da in der bisherigen Forschung vor allem Untersuchungen zu Langzeitbeziehungen überwiegen, ist es für die Zukunft interessant zu erkunden, wie sich die Partnerwahl bei kürzeren Beziehungen abspielt. Ebenfalls zukünftige Forschungsinteressen liegen in der Partnerwahl unter bestimmten Umständen wie z.B. bei Speed-Dating Events, Studien zur Partnerwahl mit Hilfe elektronischer Mittel wie dem Internet und Studien über den Lebensverlauf bzw. einzelne Lebensabschnitte der Partner

An assessment of the effectiveness of the Crossways Farm Village constructed wetland in the treatment of domestic wastewater

A mass balance study was conducted comparing inflowing and outflowing solute loads in order to calculate the treatment efficiency of a free water surface (FWS) constructed wetland used to treat domestic wastewater following primary treatment in an anaerobic reactor and oxidation in a rotating biological contractor. Water samples were taken at six locations down the length of the treatment system and analysed for nitrate nitrogen (NO3-N), nitrite nitrogen (NO2-N), ammonia nitrogen (NH4-N) and phosphorus as phosphate (PO4-P). Flow was determined using two V notch weirs combined with pressure transducers based on an empirically derived stage-discharge relationship. The concentration of each solute (g.m-3) multiplied by flow (m3.day-1) provides a measurement of the mass of each solute entering and leaving the treatment wetland such that the difference (inflow – outflow) indicates the nett storage in, or loss from, the wetland. In order to determine the water balance, apart from measuring surface inflows and outflows, rainfall was measured using an onsite rain gauge. Evapotranspirational losses were determined using the Penman-Monteith equation based on weather data collected at an onsite weather station. Other than water that entered the wetland via the primary water treatment works, surface inflows could be ignored as the wetland was sealed with a plastic liner, which also prevented groundwater inflow and outflow. Wetland outputs via surface outflow and evapotranspiration were then subtracted from wetland inputs to determine the water balance over the study period. Approximately 10.5% of water inputs into the hydrological mass balance calculation was not accounted for, which is considered to be accounted for by inaccuracy associated with the estimation of evapotranspiration and possibly by differences in water levels in the wetland at the start and end of the experiment. Total input, output and storage of NO3-N, NO2-N, NH4-N and PO4-P was calculated from April 2016 to September 2016 to give the treatment efficiency of the FWS wetland system. Results showed a 91.5% reduction in NO3-N, 76.6% reduction in NH4-N, and 88.8% reduction in PO4P between the inflow and outflow. Wetland sediment and vegetation (Typha capensis) samples were also analysed for nitrogen and phosphorus content to give an estimate of nutrient stocks/storage accumulated in plant tissues and sediments over the lifespan of the wetland. Standing stock calculations showed that a total of 450.1kg of nitrogen is stored in the wetlands, of which 69.3kg is stored in wetland sediments. Wetland phosphorus retention was found to be significantly lower with a total of 57.1kg of phosphorus, of which 77.4% was stored in sediments, indicating that wetland sediments comprise the largest store and therefore removal pathway of nutrients in the Crossways Farm Village FWS wetland

A mechanistic perspective on plastically flexible coordination polymers

Mechanical flexibility in single crystals of covalently bound materials is a fascinating and poorly understood phenomenon. We present here the first example of a plastically flexible one‐dimensional (1D) coordination polymer. The compound [Zn(μ‐Cl)2(3,5‐dichloropyridine)2]n is flexible over two crystallographic faces. Remarkably, the single crystal remains intact when bent to 180°. A combination of microscopy, diffraction, and spectroscopic studies have been used to probe the structural response of the crystal lattice to mechanical bending. Deformation of the covalent polymer chains does not appear to be responsible for the observed macroscopic bending. Instead, our results suggest that mechanical bending occurs by displacement of the coordination polymer chains. Based on experimental and theoretical evidence, we propose a new model for mechanical flexibility in 1D coordination polymers. Moreover, our calculations propose a cause of the different mechanical properties of this compound and a structurally similar elastic material

Mechanical Properties of Boehmite Evaluated by Atomic Force Microscopy Experiments and Molecular Dynamic Finite Element Simulations

Boehmite nanoparticles show great potential in improving mechanical properties of fiber reinforced polymers. In order to predict the properties of nanocomposites, knowledge about the material parameters of the constituent phases, including the boehmite particles, is crucial. In this study, the mechanical behavior of boehmite is investigated using Atomic Force Microscopy (AFM) experiments and Molecular Dynamic Finite Element Method (MDFEM) simulations. Young's modulus of the perfect crystalline boehmite nanoparticles is derived from numerical AFM simulations. Results of AFM experiments on boehmite nanoparticles deviate significantly. Possible causes are identified by experiments on complementary types of boehmite, that is, geological and hydrothermally synthesized samples, and further simulations of imperfect crystals and combined boehmite/epoxymodels. Under certain circumstances, the mechanical behavior of boehmite was found to be dominated by inelastic effects that are discussed in detail in the present work. The studies are substantiated with accompanying X-ray diffraction and Raman experiments.DFG/FOR/202

Short- and Long-Range Mechanical and Chemical Interphases Caused by Interaction of Boehmite (γ-AlOOH) with Anhydride-Cured Epoxy Resins

Understanding the interaction between boehmite and epoxy and the formation of their interphases with different mechanical and chemical structures is crucial to predict and optimize the properties of epoxy-boehmite nanocomposites. Probing the interfacial properties with atomic force microscopy (AFM)-based methods, especially particle-matrix long-range interactions, is challenging. This is due to size limitations of various analytical methods in resolving nanoparticles and their interphases, the overlap of interphases, and the effect of buried particles that prevent the accurate interphase property measurement. Here, we develop a layered model system in which the epoxy is cured in contact with a thin layer of hydrothermally synthesized boehmite. Different microscopy methods are employed to evaluate the interfacial properties. With intermodulation atomic force microscopy (ImAFM) and amplitude dependence force spectroscopy (ADFS), which contain information about stiffness, electrostatic, and van der Waals forces, a soft interphase was detected between the epoxy and boehmite. Surface potential maps obtained by scanning Kelvin probe microscopy (SKPM) revealed another interphase about one order of magnitude larger than the mechanical interphase. The AFM-infrared spectroscopy (AFM-IR) technique reveals that the soft interphase consists of unreacted curing agent. The long-range electrical interphase is attributed to the chemical alteration of the bulk epoxy and the formation of new absorption bands.DFG, 232311024, FOR 2021: Wirkprinzipien nanoskaliger Matrixadditive für den Faserverbundleichtba

Long-Time Behavior of Surface Properties of Microstructures Fabricated by Multiphoton Lithography

The multiphoton lithography (MPL) technique represents the future of 3D microprinting, enabling the production of complex microscale objects with high precision. Although the MPL fabrication parameters are widely evaluated and discussed, not much attention has been given to the microscopic properties of 3D objects with respect to their surface properties and time-dependent stability. These properties are of crucial importance when it comes to the safe and durable use of these structures in biomedical applications. In this work, we investigate the surface properties of the MPL-produced SZ2080 polymeric microstructures with regard to the physical aging processes during the post-production stage. The influence of aging on the polymeric microstructures was investigated by means of Atomic Force Microscopy (AFM) and X-ray Photoelectron Spectroscopy (XPS). As a result, a time-dependent change in Young’s Modulus, plastic deformation, and adhesion and their correlation to the development in chemical composition of the surface of MPL-microstructures are evaluated. The results presented here are valuable for the application of MPL-fabricated 3D objects in general, but especially in medical technology as they give detailed information of the physical and chemical time-dependent dynamic behavior of MPL-printed surfaces and thus their suitability and performance in biological systems.DFG, 457594480, Funktionale Polymer- und Nanokomposit-3D-Architekturen mittels Multi-PhotonenLaserstrukturierung für hochentwickelte Anwendungen in MikrobauelementenDFG, 232311024, Wirkprinzipien nanoskaliger Matrixadditive für den Faserverbundleichtba