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Drought resistance of Douglas-Fir in central europe: Future viability and comparison to other temperate tree species
No full textThe climatic changes, which manifest in rising temperatures and increasing dryness, pose a significant challenge to terrestrial ecosystems. Trees, due to their sessile lifestyle and specific adaptation to a given location, are considered particularly vulnerable and are especially affected by these changes, primarily because of the rapid pace at which the environment is changing. Droughts are among the phenomena that are expected to occur more frequently in the future and will become increasingly extreme due to climate change. These are therefore referred to as 'climate change type drought events' or 'hot droughts.' The responses of tree species to drought vary considerably, making it crucial to understand the species-specific strategies for drought tolerance in order to select the most resilient species and provenances for future forests.
Douglas-fir (Pseudotsuga menziesii), originating from North America, is a widely distributed tree species in Europe and is considered a promising species for the future because it exhibits good drought adaptation while also having high economic value. This study aims to investigate the drought tolerance of different Douglas-fir provenances and seeks to describe the fundamental strategic differences in desiccation time between angiosperms and gymnosperms based on their hydraulic capacitance. The study focuses on two central hypotheses: (I) that Douglas-fir provenances from certain regions are more resistant to drought and therefore better suited for climate-resilient forests, and (II) that hydraulic capacity plays a crucial role in the drought tolerance of temperate gymnosperms and angiosperms.
To test these hypotheses, we conducted a gradient study in Central Europe on mature Douglas-fir trees and a drought stress experiment with 16 different temperate tree species. Several ecophysiological, morphological, and growth-related traits were measured, including hydraulic parameters, leaf morphology, carbon isotope ratios in leaves, xylem anatomical characteristics, and dendrochronological measurements.
The results show that Douglas-fir provenances from the northern interior regions grow more slowly and have a lower growth rate compared to provenances from coastal regions. This is associated with an adaptation to higher frost tolerance and appears to be genetically fixed. Provenances from the northern interior regions also demonstrated greater drought tolerance during the pan-European drought events of 2003 and 2018. Interestingly, dendroecological analysis revealed that these provenances had the lowest resistance but equal or even higher recovery rates. This is considered a drought-adapted behavior and is attributed to a more plastic stomatal response.
On a leaf morphological level, we observed a significant reduction in the specific leaf area (SLA) in the northern interior provenances, which correlates with slower growth and reduced photosynthetic area. This trait implies a smaller leaf surface area, and consequently, reduced transpiration area, which contributes to better drought tolerance. However, the physiological values of hydraulic efficiency (Huber value, leaf δ13C as a proxy for intrinsic water use efficiency iWUE) and hydraulic safety (P12, P50) showed no significant differences. For the hydraulic safety related to embolism resistance (P12, P50), this is not surprising, as these values are considered evolutionarily constrained in conifers and therefore show little variation.
When comparing desiccation times in young trees of 16 different temperate tree species, Douglas-fir exhibited the second-longest desiccation time after larch (Larix decidua), closely followed by silver fir (Abies alba). The ranking of the tree species clearly shows longer desiccation times for gymnosperms compared to angiosperms. This is largely due to experimental factors, such as insufficient pot volume for taproot species. However, it is also partly related to strategic behavior. The study on hydraulic capacitance shows that gymnosperms store more water in their stems than angiosperms and have a higher hydraulic capacity. This allows gymnosperms to utilize more stored water during droughts, helping them cope better. Gymnosperms also reduce their hydraulic capacity earlier in the desiccation phase compared to angiosperms.
This study provides strong evidence that northern interior provenances in Central Europe are more resilient to drought compared to coastal provenances. This means that provenance selection is a crucial factor in creating climate-resilient forests. Furthermore, compared to other temperate tree species, Douglas-fir demonstrates high drought tolerance, reflected in longer desiccation times. This suggests that Douglas-fir holds great potential for climate-resilient forests and, in combination with the right provenance choice, can play a key role.
Finally, the study highlights the importance of understanding the various physiological and morphological strategies employed by different tree species in response to drought. Future research should further investigate the genetic mechanisms behind these adaptations and explore the potential of other species to adapt to changing climate conditions, particularly through additional gradient studies and manipulative experiments.:Table of contents I
Summary V
Zusammenfassung VII
Abbreviations IX
Chapter 1 2
1. General Introduction 2
1.1. Temperate forest ecosystems and droughts 2
1.2. Tree hydraulic and strategies under drought conditions 3
1.2.1. Water transport and the water potential 4
1.2.2. The influence of drought on the tree hydraulic system 5
1.2.3. Tree drought reaction strategies and the role of the water storage capacitance 6
1.3. Phenotypic plasticity and the importance in climate change 8
1.4. Tree ring growth in terms of climate change and droughts 9
1.5. Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) 9
1.6. Project objectives 10
1.7. Experimental design, study sites, and measured parameters 11
1.7.1. Part I: Gradient study 11
1.7.2. Part II: Greenhouse drying out experiment 12
1.7.3. Summary of parameters 14
Chapter 2 16
2. Radial growth reduction during extreme drought of Douglas-fir provenances across a climatic gradient in Central Europe 17
2.1. Introduction 17
2.2. Materials and Methods 19
Study sites 19
Climatic data 21
Provenance clustering 21
Tree structure and aboveground biomass increment 22
Wood core sampling, preparation, and processing 23
Drought response indices 23
Data analysis 23
2.3. Results 24
Long-term aboveground biomass and radial growth increment 24
Growth-response during extreme drought exposure 26
Drought response indices 27
2.4 Discussion 30
Growth behavior of the climate-at-origin groups across the gradient 31
Vulnerability of radial growth to extreme drought events 32
Drought response indices 33
Implementations to future management decisions 33
Conclusion 35
Chapter 3 36
3. The effect of climate at origin on Douglas-fir growth, leaf traits, and embolism resistance along a rainfall gradient in Central Europe 37
3.1. Introduction 37
3.2. Material and Method 39
Study sites and climate 39
Provenance selection and clustering into climate-origin groups 42
Tree structure and aboveground biomass increment 43
Branch sampling 43
Vulnerability curves 43
Leaf traits 44
Statistical analysis 44
3.3. Results 45
Differences between climate-origin groups 45
Variation in functional traits along the climatic gradient 47
Intra-specific trait variability on different levels of organization 50
3.4. Discussion 51
Trait variability between climate-origin groups 51
Effects of water availability along the gradient on trait variability 53
Sources of variation on different levels of organization 54
Conclusion 55
Chapter 4 56
4. Water storage strategies in drought conditions: The fundamental differences between broad-leaf trees and conifers of temperate forests 57
4.1. Introduction 57
4.2. Material and Method 60
Plant material 60
Shoot hydraulic capacitance and water content 60
Wood density and saturated water content 63
Vulnerability curves 63
Vessel anatomical traits from light microscopy 63
Leaf traits 64
Data analysis 64
4.3. Results 65
Water stored, xylem anatomy, and xylem vulnerability 65
Shoot hydraulic capacitance phases 66
Water relations at different stages of drought 69
Shoot capacitance in relation to xylem structure and stored water 71
4.4. Discussion 73
The different water storage and Cshoot strategies in a drought situation 73
Cshoot and the relation to xylem anatomy 74
Conclusion 75
Chapter 5 76
5. Synthesis 77
5.1. Douglas-fir: The drought resistance of different provenances 77
5.2. Temperate conifers and angiosperms under drought 80
5.3. Determination of desiccation times for temperate tree species 82
5.4. Outlook 85
References 87
Appendices 120
Chapter 2 121
Chapter 3 139
Chapter 4 151
Acknowledgments 153
Curriculum Vitae 154
Anlage 1 157
Anlage 2 15
Investigation of Modes of Toxic Action of Ionic Liquids by In vitro Cell-based Bioassays
No full textDer umfangreiche Einsatz ionischer Chemikalien in der Industrie rückt auch Bedenken bezüglich ihrer Auswirkungen auf die menschliche Gesundheit und die Umwelt stärker in den Mittelpunkt des Interesses. Die aktuell gebräuchlichen Modelle und Methoden zur Risikobewertung von Chemikalien konzentrieren sich bisher jedoch hauptsächlich auf neutrale organische Verbindungen, was ihre direkte Anwendung für ionische Verbindungen einschränkt. Für eine bessere Risikobewertung ionischer Chemikalien sind zuverlässige Daten für eine Vielzahl von Strukturen erforderlich, um die Standardmethoden zu verfeinern. Ionische Flüssigkeiten (Ionic Liquids, ILs) können als epitome chemische Gruppe für Struktur-Aktivitäts-Beziehungen (engl. Structure-activity relationships, SAR) betrachtet werden. Ihre Verwendung kann dazu beitragen, Datenlücken für ionische Chemikalien zu schließen und zur Entwicklung von Vorhersagemodellen beizutragen. Mechanistisches Wissen über die toxischen Wirkungsweisen (engl. Mode of toxic action, MOA) einer chemischen Verbindung ist für die Risikobewertung von entscheidender Bedeutung, doch ist in diesem Kontext über ILs nur wenig bekannt. Ein zellbasierter In-vitro-Bioassay bietet einen leistungsstarken Ansatz zur systematischen Untersuchung der MOAs. Das übergeordnete Ziel dieser Arbeit war daher die Anwendung von In-vitro-Bioassay-Ansätzen zur Erforschung der MOAs von ILs. Diese Arbeit zielte insbesondere darauf ab, 1) die potenzielle MOA von ILs zu untersuchen und s die wichtigsten Strukturelemente zu identifizieren, 2) die Wechselwirkungen ausgewählter IL-Strukturen mit Bioassay-Komponenten zu untersuchen und 3) nach einem potenziellen Analyseinstrument zur Expositionsbewertung von IL-Kationen in einem In-vitro-Bioassay zu suchen.
Die Zytotoxizitätsdaten von 45 ILs, die systematisch für SAR-Studien ausgewählt wurden, wurde in Hochdurchsatz-Reportergen-Assays (AREc32- und AhR-CALUX-Assays) bewertet. Die Ergebnisse zeigten, dass die Hydrophobizität eine Schlüsselrolle für die Zytotoxizität in drei untersuchten Zelllinien spielt. Gemessene frei gelöste Konzentrationen im Medium (engl. Cfree) zeigten darüber hinaus einen kontinuierlichen Anstieg der Toxizität mit zunehmender Hydrophobizität, selbst jenseits einer Seitenkettenlänge von ≥ 12 Kohlenstoffen, für welche in verschiedenen Toxizitätsstudien bereits ein Seitenketten-Cut-off-Effekt vermutet wurde. Trotz der starken Korrelation zwischen Zytotoxizität und Hydrophobizität wurden erhebliche Unterschiede zwischen den gemessenen zytotoxischen Konzentrationen und den für die Basistoxizität vorhergesagten Konzentrationen festgestellt. Darüber hinaus variierte die Zytotoxizität erheblich zwischen den Zelllinien und den chemischen Gruppen der untersuchten ILs (organische Kationen vs. komplexe Anionen), was für die Basislinientoxizität von neutralen organischen Verbindungen nicht beobachtet wurde. Alle Ergebnisse deuten darauf hin, dass entweder 1) (einige) ILs eine spezifische Wirkungsweise (MOA) haben, die über die Basislinientoxizität hinausgeht, oder 2) dass das Basislinientoxizitätsmodell für ILs möglicherweise nicht universell anwendbar ist, sondern zelllinien- oder gruppenspezifisch variiert. Daraufhin wurde die spezifische MOA von ILs durch Reportergen-Aktivierungs-Assays und eine Tox21-Bibliotheksanalyse untersucht. Alle beobachteten MOAs schienen jedoch unspezifisch ausgelöst zu werden, da sie bei Konzentrationen auftraten, die denen zur Auslösung von Zytotoxizität entsprachen. Darüber hinaus war die Bildung bioreaktiver Metaboliten unwahrscheinlich, da nur bei einigen wenigen quaternären Ammoniumverbindungen eine Seitenkettenoxidation festgestellt wurde.
Anstatt das Vorhandensein spezifischer MOAs anzunehmen, wurde untersucht, inwieweit eine Verbesserung der Vorhersagemodelle für Basislinientoxizität von ILs erforderlich ist. Zu diesem Zweck wurde die Verteilung von ILs im In-vitro-Bioassay im Detail charakterisiert. Der Schwerpunkt lag auf organischen Kationen von ILs mit langen Alkylketten (≥ 8 Kohlenstoffe), da diese Strukturen durchweg die ausgeprägteste Zytotoxizität und die größten Abweichungen im Vergleich zur vorhergesagten Basislinientoxizität aufwiesen. Die speziellen Verhaltensweisen von IL-Kationen, wie die verstärkte Bindung an Kunststoffoberflächen und stärkere Affinität zu Membranlipiden im Vergleich zu Proteinen, zeigten ihre unterschiedlichen Wechselwirkungen mit Bioassay-Komponenten. Das verbesserte Massenbilanzmodell (MBM) mit experimentellen Verteilungsdaten lieferte eine gute Vorhersage der frei gelösten Anteile der untersuchten Verbindungen im Bioassay-Medium und bewies damit seine Anwendbarkeit für IL-Kationen. Insbesondere wurde eine signifikante Abweichung zwischen der frei gelösten Konzentration (Cfree) und der nominalen Konzentration (engl. Cnom) für IL-Kationen mit einem Membranlipid-Wasser-Verteilungskoeffizienten (engl. Kmw) von mehr als 5,5 log-Einheiten beobachtet, was die Bedeutung der Cfree-Bestimmung für eine stark mediumgebundene Chemikalie hervorhebt. Andererseits unterschätzte das MBM die Zellaffinität von IL-Kationen im Vergleich zu experimentell ermittelten Werten erheblich. Dieser Befund deutet darauf hin, dass die Interaktion von IL-Kationen mit Zellen komplexer ist, als es der Verteilungskoeffizient, der von einer einzigen Art von Phospholipid (d. h. Phosphatidylcholin) und Protein (d. h. Serumalbumin) abgeleitet wurde, erwarten lässt. Schließlich wurden die Konzentrationen in den Zellmembranen, die aus den gemessenen Kmw- und Cfree-Werten abgeleitet wurden, mehrere IL-Kationen, die zuvor im AREc32-Assay als excess toxicants identifiziert worden waren, als basislinientoxisch neu klassifiziert. Die Klassifizierung der Basistoxizität war jedoch von Zelllinie zu Zelllinie unterschiedlich, so dass die zugrundeliegenden Ursachen weiter erforscht werden müssen. Alle Ergebnisse unterstreichen die Notwendigkeit, spezifische Eigenschaften von IL-Kationen in Vorhersagemodellen zu berücksichtigen, anstatt sich auf Modelle zu stützen, die auf neutralen organischen Chemikalien basieren.
Die μElution-Platte für die Festphasenextraktion (engl. Solid-phase extraction, SPE), die mit einem schwachen Kationenaustausch-Sorbens (engl. Weak cation exchange, WCX) eingebettet ist, wurde als Hilfsmittel für die Cfree-Quantifizierung von IL-Kationen in Bioassay-Medien bewertet. Die Wechselwirkungen zwischen dem SPE-Sorptionsmittel und IL-Kationen, wie die Bindungsisotherme und die Gleichgewichtskinetik, wurden charakterisiert. Die SPE-Platte zeigte eine hohe Affinität und die selektive Sorption aller getesteten IL-Kationen aus dem Bioassay-Medium. Die mit der SPE-Platte gemessenen Cfree-Werte stimmten jedoch nur für hydrophobe IL-Kationen mit einer langen Seitenkette (≥ 14 Kohlenstoffe) mit denen überein, die durch Dialyse ermittelt wurden. Ihre hohe Affinität zu den Bestandteilen des Mediums könnte dazu führen, dass nach dem Kontakt mit dem SPE-Sorptionsmittel ein hoher chemischer Anteil (>30 %) in der Probe verbleibt, der eine vollständige Abreicherung in der Probe verhindert und eine zuverlässige Probenahme ermöglicht. Die Ergebnisse geben Aufschluss über das Potenzial des WCX-Sorptionsmittels für die selektive IL-Kationenextraktion. Die Optimierung der Sorptionsmittelmenge oder der Probenkontaktzeit könnte die Anwendung für die Bewertung der IL-Kationen-Exposition verbessern.
Insgesamt trägt diese Arbeit nicht nur zur effektiven Durchführung von In-vitro-Bioassays für MOA-Untersuchungen bei, sondern fördert auch das Verständnischemischer Verteilungsprozesse, was die Expositionsbewertung verbessern und die Vorhersagemodelle für ILs verfeinern kann. Die daraus gewonnenen Erkenntnisse bilden zusammen mit den noch offenen Fragen eine Grundlage für künftige Studien, um das mechanistische Verständnis der toxischen Wirkungen von ILs aufzuklären und deren Risikobewertung zu verbessern.The extensive use of charged chemicals in industries has increased concerns about their impacts on human health and the environment. However, current chemical risk assessment have mainly focused on neutral organic chemicals, limiting their direct application to charged chemicals. For a better risk assessment of charged chemicals, reliable data covering a diverse set of structures is required to refine the standard methods. Ionic liquids (ILs) can be proposed as an epitome chemical group for structure activity relationship (SAR) studies. Their use can help fill data gaps for charged chemicals and contribute to the development of predictive models. Mechanistic knowledge of the modes of toxic action (MOA) of a chemical is crucial for risk assessment, yet little is known about ILs. An in vitro cell-based bioassay provides a powerful approach to systematically investigate the MOA. Therefore, the overarching objective of this thesis was to implement in vitro bioassay approaches to explore the MOA of ILs. Specifically, this work aimed to 1) screen potential MOA of ILs and identify key structural elements governing theses effects, 2) investigate the interactions of selected IL structures with bioassay components, and 3) search for a potential analytical tool for exposure assessment of IL cations in an in vitro bioassay.
Cytotoxicity of 45 ILs, systematically selected for SAR studies, was evaluated in high-throughput reporter gene assays (AREc32 and AhR-CALUX assays). Results showed that hydrophobicity plays a key role in determining cytotoxicity across three investigated cell lines. Despite the strong correlation between cytotoxicity and hydrophobicity, considerable differences were observed between measured cytotoxic concentrations and concentrations predicted for baseline toxicity. Moreover, cytotoxicity varied considerably between the cell lines and chemical groups (organic cations vs complex anions), which was not observed for neutral organic baseline toxicants. All findings indicated either 1) that (some) ILs have specific MOA beyond baseline toxicity, or 2) that the baseline toxicity model for ILs may not be universal, but rather cell line- or chemical group-specific. In response, the specific MOA of ILs was explored through reporter gene activation assays and Tox21 library analysis. However, all observed effects appeared to be nonspecific as they occurred at concentrations similar to cytotoxicity. Additionally, the formation of bioreactive metabolites was unlikely since only side chain oxidation was detected in a few quaternary ammonium compounds.
Instead of assuming the presence of a specific MOA, the need to improve the baseline toxicity prediction for ILs was assessed by investigating the partitioning of ILs in in vitro. The focus was placed on organic cations of ILs with long alkyl chain lengths (≥ 8 carbons), as these structures consistently exhibited the most pronounced cytotoxicity and the largest deviations from predicted baseline toxicity. The behaviors of the IL cations, such as enhanced binding to a plastic plate, and stronger affinity for membrane lipids compared to proteins, demonstrated their distinct interactions with bioassay components. The improved mass balance model (MBM) with experimental partitioning data provided a good prediction of the freely dissolved chemical fractions in the bioassay medium, confirming its applicability to IL cations. A significant deviation between the freely dissolved concentration (Cfree) and the nominal concentration (Cnom) was observed for IL cations with a membrane lipid-water partition coefficient (Kmw) higher than 5.5 in log units, highlighting the importance of Cfree assessment for a highly medium-bound chemical. On the other hand, the MBM underestimated cell affinity of IL cations compared to experimentally determined values. This finding implies that the interaction of IL cations with cells is more complex than expected simply based on partition coefficients derived from a single type of phospholipid (i.e., phosphatidylcholine) and protein (i.e., serum albumin). Finally, the concentrations in cell membranes, derived from the measured Cfree and Kmw, reclassified several IL cations, previously identified as excess toxicants in the AREc32 assay, as baseline toxicants. However, the baseline toxicant classification differed between different cell lines, addressing a further need to elucidate the underlying causes. All results highlight the need to consider specific properties of IL cations in predictive models, rather than relying on those based on neutral organic chemicals.
The μElution solid-phase extraction (SPE) plate containing weak cation exchange (WCX) sorbent was evaluated as a tool for Cfree quantification of IL cations in bioassay medium. The interactions between the SPE sorbent and IL cations, such as the binding isotherm and equilibrium kinetics, were characterized. The SPE plate showed high affinity and the selective sorption of all tested IL cations from the bioassay medium. However, the Cfree values measured by the SPE plate agreed with those derived by dialysis only for hydrophobic IL cations with a long side chain (≥ 14 carbons). Their high affinity for medium components could leave a high chemical fraction (>30%) in the sample after contact with the SPE sorbent, preventing a complete depletion in the sample and allowing for a reliable sampling. The results shed light on the potential of the WCX sorbent for selective IL cation extraction. Optimizing the sorbent amount or sample contact time may enhance its application for IL cation exposure assessment.
Altogether, this work not only contributes to the effective implementation of in vitro bioassays for MOA investigations, but also advances the understanding of chemical partitioning that can strengthen the exposure assessment and refine predictive models for ILs. The knowledge gained from this, along with the remaining open questions, provides a foundation for future studies to elucidate the mechanistic understanding of the toxic effects of ILs and to improve risk assessment
Mit Kollaboration zum Standard: Empirisch basierte Bestimmung von Lehrkräfte-Expertise im Bereich Deutsch als Zweitsprache (DaZ)
Get PDFDer Beitrag befasst sich mit dem kollaborativen und zugleich empirisch basierten Prozess des Standardsettings in einem interdisziplinären Forschungsprojekt, welches Lehrkräfte-Expertise im Bereich Deutsch als Zweitsprache (DaZ) mithilfe von Aufgaben zu kurzen Unterrichtsvideos erfasst hat. Ausgehend von Annahmen aus der Expertiseforschung steht dabei die Frage im Fokus, wie sich anhand der Testergebnisse von N = 295 angehenden und praktizierenden Lehrkräften sowie unter der aktiven Beteiligung von einschlägigen Fachexpert*innen mithilfe der Bookmark-Methode theorie- und datenbasiert Schwellen von Kompetenz ermitteln lassen. Eine inhaltliche Beschreibung der im Beitrag hergeleiteten Kompetenzniveaus entlang eines Beispiel-Testitems schließt die Darstellung des Prozesses ab. Interpretiert werden die in der Stichprobe erreichten Kompetenzniveaus mit Bezug auf die Lehrer*innenbildung im Bereich DaZ.The article deals with the collaborative and at the same time empirically based standard setting procedure in an interdisciplinary research project. The project assessed teacher expertise in the field of German as a Second Language (GSL) using tasks on short instructional videos. Based on assumptions from expertise research, we determine thresholds of competence in a theory- and data-based manner using the bookmark method. The procedure uses N = 295 prospective and practising teachers’ test results while also depending on the active participation of relevant experts. We conclude the procedure by describing the competence levels derived in the article along an example test item. Finally, we interpret the competence levels achieved in the sample with reference to teacher training in the field of GSL
Economic fatigue damage monitoring for vehicle fleets using the scattering transform
Get PDFVehicle monitoring is an important prequisite for predictive maintenance applications. Virtual sensors can be deployed to establish relationships between fatigue related quantities of interest and readily available measurement data, which reduces the costs of monitoring for vehicle fleets. This work describes a data-driven virtual sensing approach using the scattering transform and principal component analysis. These data transformations are used to obtain a reduced representation of acceleration data, which is suitable for the identification of fatigue critical events during vehicle operation. Results of a previous study using an eBike demonstrator are summarized and the methodology is applied to experimental data of a sensor equipped light rail vehicle. In both applications, fictitious fatigue damage contributions are estimated accurately and physical interpretations of the reduced representation are found
Investigation of the influence of the torso, lips and vocal tract configuration on speech directivity using measurements from a custom head and torso simulator
Get PDFThe human voice is a directional sound source. This property has been explored for more than 200 years, mainly using measurements of human participants. Some efforts have been made to understand the anatomical parameters that influence speech directivity, e.g., the mouth opening, diffraction and reflections due to the head and torso, the lips and the vocal tract. However, these parameters have mostly been studied separately, without being integrated into a complete model or replica. The aim of this work was to study the combined influence of the torso, the lips and the vocal tract geometry on speech directivity. For this purpose, a simplified head and torso simulator was built; this simulator made it possible to vary these parameters independently. It consisted of two spheres representing the head and the torso into which vocal tract replicas with or without lips could be inserted. The directivity patterns were measured in an anechoic room with a turntable and a microphone that could be placed at different angular positions. Different effects such as torso diffraction and reflections, the correlation of the mouth dimensions with directionality, the higher-order modes and the increase in directionality due to the lips were confirmed and further documented. Interactions between the different parameters were found. It was observed that torso diffraction and reflections were enhanced by the presence of the lips, that they could be modified or masked by the effect of higher-order modes and that the lips tend to attenuate the effect of higher-order modes
Association between maternal employment and the child´s mental health: a systematic review with meta‑analysis
Get PDFThe recent rise in maternal workforce participation has led to more research regarding the role of maternal employment for (early) childhood mental health. This systematic review with meta-analysis covers new evidence on the association of both variables. A systematic literature search was conducted. Studies had to compare children 0–7 years of age on the basis of their mothers’ employment status, working amount, employment duration, i.e., how long the mother had been back at work after birth, or timing of return to work. Child mental health was operationalized as behavior problems and prosocial behavior. Narrative and meta-analytic syntheses of evidence were conducted. Maternal employment was associated with more conduct problems but less internalizing behavior problems and anxious/depressed behavior in children; full-time employment was linked to more externalizing behavior problems and more hyperactivity/inattention. Longer employment duration was related to less (internalizing) behavior problems and more prosocial behavior but also more externalizing behavior problems. Narrative syntheses indicated early maternal return to work to be associated with more child externalizing behavior problems and less prosocial behavior. Whether maternal employment is associated with child mental health strongly depends on both variables’ operationalization. Especially part-time employment, longer employment duration, and return to work only after the first year postpartum may be beneficial for child mental health. Practical implications pertain to an expanded offer of family leave and the endorsement of maternal employment after the first year postpartum. Here, factors that may buffer the negative associations with full-time employment warrant consideration
Entwicklungsanamnese und Familienanamnese bei Anorexia nervosa: Evaluation des Diagnostikinstruments Anamnese am Beispiel etablierter Items
Get PDFHintergrund Die Anamnese spielt als Diagnostikinstrument eine wichtige Rolle in der Medizin. Sie kann sowohl die Diagnosestellung als auch den weiteren Verlauf und die Behandlung einer Erkrankung maßgeblich beeinflussen. In der Kinder- und Jugendpsychiatrie kommt der Anamnese eine besonders wichtige Rolle zu. Eine Herausforderung für die Untersuchenden besteht hierbei in einer ausreichend detaillierten und zugleich präzisen Erhebung der Anamnese. Fragestellung Im Rahmen dieser Studie erfolgte die strukturierte Erprobung und Evaluierung des Diagnostikinstruments Anamnese anhand etablierter Items. Hier wurden die Entwicklungs- und Familienanamnese von AN-Patientinnen im Vergleich mit einer Kontrollgruppe im Rahmen eines strukturierten klinischen Interviews erfasst. Folgende Hypothesen wurden untersucht: Hypothese 1: Anhand der untersuchten Items ergibt sich ein Anamnese-Profil der Entwicklungs- und Familiengeschichte der AN-Patientinnen, welches sich statistisch signifikant von dem der Kontrollgruppe unterscheidet. Hypothese 2: Das Anamnese-Profil der AN-Patientinnen stimmt mit dem aktuellen Stand der Wissenschaft überein. Material und Methoden
Mittels eines Dokumentationsbogens, welcher in Zusammenschau etablierter Anamnese-Items durch Experten der Kinder- und Jugendpsychiatrie erstellt wurde, erfolgte die retrospektive Anamnese. Hierbei handelte es sich um eine Fremdanamnese durch jeweils einen Elternteil. Die Stichprobe umfasste 96 Probandinnen. Hiervon hatte ein Teil im Alter von 12-17 Jahren die Diagnose einer AN erhalten (n = 52), während der andere Teil keine psychiatrische Erkrankung aufwies und somit als Kontrollgruppe (n = 44) diente. Die mittels strukturiertem klinischen Interview erhaltenen Informationen wurden anhand einer Kategorisierung (0 – normales Verhalten; 1 – leicht pathologisches Verhalten; 2 – stark pathologisches Verhalten) in numerische Daten überführt und durch diese Operationalisierung einer statistischen Auswertung zugänglich gemacht. Ergebnisse: Es ergaben sich statistisch signifikante Unterschiede in der Entwicklungs- und Familienanamnese der beiden Gruppen. Somit konnte anhand der untersuchten Items ein Anamnese-Profil der AN erhoben werden, welches sich von dem der Kontrollgruppe unterscheidet (Hypothese 1). Dieses Anamneseprofil stimmt überwiegend mit dem aktuellen Stand der Wissenschaft überein (Hypothese 2). Schlussfolgerungen: Somit stellen die hier untersuchten Items ein valides diagnostisches Messinstrument zur Erhebung der Entwicklungs- und Familienanamnese von AN-Patientinnen dar. Die in der Studie erhaltenen Ergebnisse unterstreichen den Stellenwert der Anamnese in der Diagnostik und legen eine weitere Auseinandersetzung mit der Anwendung und empirischen Evaluation von Anamneseverfahren nahe
Development of yarns from recycled carbon fiber based on friction spinning technology with specific properties for thermoset composites
Get PDFBecause of a growing demand and usage of carbon fiber, effective methods to re-use waste and recycled carbon fiber recoverable either from process scraps or from end-of-life components are attracting increased attention. The development of different hybrid yarn structures consisting of recycled carbon fiber and thermoplastic fibers (recycled carbon fiber content approx. 50% by weight) for thermoplastic composites have been reported earlier. Yarns with high recycled carbon fiber content (>90% by weight) required for thermoset composites are still not realizable due to high shortening in recycled carbon fiber length (≥70%) during different processing steps of spinning. The reason lies in low shear strength, smooth fiber surface and high brittleness of recycled carbon fiber. Second, a lack of crimp in recycled carbon fiber leads to drafting errors during the drawing and spinning process. In this paper, the spinning limit regarding the core to sheath ratio of noble yarns with a recycled carbon fiber content greater than 90% by weight based on friction spinning technology for thermoset composites is reported. Slivers of recycled carbon fiber solely required for the development of yarns are produced on carding and drawing machines optimized for the gentle processing of recycled carbon fiber. Furthermore, different spinning parameters such as spinning drum speed and suction air pressure are investigated and their effect on tensile properties of yarn is analyzed. The results show that yarns with high recycled carbon fiber content (>90% by weight) can be produced with reproducible quality on the DREF-3000 friction spinning machine
Cohesin SMC1β promotes closed chromatin and controls TERRA expression at spermatocyte telomeres
Get PDFPrevious data showed that meiotic cohesin SMC1β protects spermatocyte telomeres from damage. The underlying reason, however, remained unknown as the expressions of telomerase and shelterin components were normal in Smc1β−/− spermatocytes. Here. we report that SMC1β restricts expression of the long noncoding RNA TERRA (telomeric repeat containing RNA) in spermatocytes. In somatic cell lines increased TERRA was reported to cause telomere damage through altering telomere chromatin structure. In Smc1β−/− spermatocytes, we observed strongly increased levels of TERRA which accumulate on damaged chromosomal ends, where enhanced R-loop formation was found. This suggested a more open chromatin configuration near telomeres in Smc1β−/− spermatocytes, which was confirmed by ATAC-seq. Telomere-distal regions were not affected by the absence of SMC1β but RNA-seq revealed increased transcriptional activity in telomere-proximal regions. Thus, SMC1β promotes closed chromatin specifically near telomeres and limits TERRA expression in spermatocytes
Cybersickness as the virtual reality sickness questionnaire (VRSQ) measures it!? –an environment-specific revision of the VRSQ
Get PDFBackground: Virtual Reality (VR) does not only include the use of stereoscopic images, but also possibilities for an interaction with and participation in a computer-generated environment. However, laboratory studies primarily focus on the first part of the definition only. In this context, comparing results from different VR applications with diverging goals becomes difficult. This is especially true in the field of cybersickness research (visually induced motion sickness in VR), as self-report symptom questionnaires are used. The prominent Simulator Sickness Questionnaire (SSQ) is criticized for the lack of specificity, the double factorial loadings, the outdatedness, and the unrepresentative sample. VR-specific revisions like the Virtual Reality Sickness Questionnaire (VRSQ) address these criticisms but lack generalizability.
Methods: The current paper uses a Confirmatory Factor Analysis of the VRSQ with data from three different VR environments and a sample size of N = 244. The environments had different setups, visual complexities, and interaction possibilities. These characteristics influenced the factorial structure of the VRSQ as a moderator. Furthermore, to control for VR-unrelated effects Baseline ratings were taken into account.
Results: The Confirmatory Factor Analysis indicated a moderate fit for the global model, but a misspecification for two of the three environments. Only the environment similar to the original VRSQ paper converged with the model.
Conclusions: In conclusion, a detailed description of the VR environment is required in scientific method reports. Focusing on VR accessibility for physically impaired in addition to healthy subjects, an added Baseline measurement can address the discriminant validity. Until generalizable VR-specific revisions of the SSQ are validated, the paper suggests using the Δ-SSQ in aggregated raw format