Elektrische Transporteigenschaften von hochorientiertem pyrolytischen Graphit (HOPG)

In dieser Arbeit wurden die elektrischen und galvanomagnetischen Eigenschaften von hoch orientiertem pyrolytischen Graphit (HOPG) untersucht. Nach der Offenbarung von ungewöhnlichen Phänomenen im 2004 neu entdeckten alleinstehenden Graphen, stieg auch das Interesse an verwandten Kohlenstoffstrukturen. Trotz zahlreicher Untersuchungen bestehen nach wie vor Unklarheiten über so manche Transporteigenschaften von Graphit. Ziel dieser Arbeit ist es anhand von (Magneto)widerstands- und Hall-messungen die Ladungsträgerkonzentrationen und -beweglichkeiten von Elektronen und Löchern in Graphit unter zur Hilfenahme des Zweiband-modells zu ermitteln. Ferner werden in Abhängigkeit von Temperatur und Magnetfeld die Änderungen der Transporteigenschaften durch Gitterdefekte, Verunreinigungen und der Kristallitausrichtungen des Graphits an den Messresultaten von HOPG und im Vergleich zu anderen Graphitproben erläutert. Durch das Auftreten von Anomalien im Halleffekt und in der Magnetfeldabhängigkeit des Magnetowiderstandes wird die Beteiligung von Effekten durch die dreieckige Fermi-Oberflächen-Verzerrung und von Dirac-Fermionen genauer thematisiert. Dazu werden im Temperaturbereich von 10 bis 300K Messungen des Widerstandes, sowohl in den Graphitebenen, als auch senkrecht dazu vorgenommen. Ebenso unter Einwirkung eines Magnetfeldes senkrecht, als auch parallel zu den Graphitebenen. Genauso erfolgen Hallmessungen bei konstantem Magnetfeld bei beiden Magnetfeldrichtungen. Der Widerstand der Graphitebenen zeigt metallisches Verhalten über den gesamten Temperaturbereich. Der c-Achsen-Widerstand zeigt selbiges nur bis zu 36K - für Temperaturen darüber weist dieser Halbleiter-Verhalten auf. Bei 11K und 1T (senkrecht zu den Ebenen) konnte ein magnetoresistiver Effekt von über 11000% gemessen werden - für parallel orientierte Magnetfelder tritt keiner auf. Ein Halleffekt kann ebenfalls nur bei senkrechten B-Felder gemessen werden – bei einem Magnetfeld von 1T weist dieser stets negative Werte auf.The aim of this thesis was the investigation of the electrical and galvanomagnetic properties of highly oriented pyrolytic graphite. There has been a huge interest in graphite and related carbon-structures, after the revelation of unusual and unexpected phenomena on separated graphene in 2004. Plenty of examinations have been done on graphite, unclarities still remain in many transport properties. In this work (magneto)resistance- and Hall-measurements were performed, to examine the concentrations and mobilities of electrons and holes by using a two-band-model. The changes in the transport properties due to lattice-defects, contaminations and orientation of crystallites in terms of magnetic field and temperature will be discussed, also in comparison to other samples. Due to the appearance of anomalies in the Hall-effect and the magnetic-field-dependence of the magnetoresistance we will discuss a possible involvement of the effects of trigonal warping and Dirac-fermions. Measurements of the resistance along the graphite planes and perpendicular to them in the temperature range of 10 to 300K are presented. In addition, a magnetic field is applied parallel and perpendicular to the planes for magnetoresistance measurements. The Hall-effect is evaluated at constant field in the conventional in-plane arrangements, as well as for out-of-plane Hall fields. The resistance in the graphite planes shows metallic behaviour over the entire temperature range. The c-axis-resistance exhibits the same behaviour to 36K. For higher temperatures a semi-conductor-like dependence is seen. A magnetoresistive effect of 11000% has been measured at 11K and 1T (applied perpendicular to the graphite planes) – for parallel fields no effect could be detected. Hall-effect measurements are successful only at perpendicular fields – resulting in a negative Hall coefficient for 1T

"Sustainability is a nice Bonus" the role of sustainability in carsharing from a consumer perspective

Carsharing has been discussed as one of the most prominent examples of the sharing economy. The worldwide growth of services whereby consumers share access to cars rather than owning a car themselves could be a sustainable solution to environmental problems. However, first research indicates that consumers' environmental concerns play a minor role for using a carsharing compared to financial considerations. Moreover, prior research on B2C carsharing services may not be applicable to P2P services. The current research addresses this gap by investigating the role of sustainability in B2C and P2P carsharing from consumers' perspective. By applying quantitative as well as qualitative methods three studies show that consumers' image of carsharing is "greener" than owning a car and that environmental concerns play a role when consumers decide to use P2P service over B2C services. However, interviews with carsharing users indicate that the sustainable impact of carsharing is rather perceived as a positive side effect than a main argument for carsharing. This should be considered by policy makers and marketers when promoting carsharing because of sustainable benefits

Preventing Conflicts in Sharing Communities as a Means of Promoting Sustainability

The sharing economy is a new promising trend with many positive outcomes on society and the environment, as it provides potential for sustainable solutions due to the reduction of resource consumption and less waste. However, research and practice show that sharing comes with its own share of problems. People often act selfishly, and in worst-case scenarios try to take advantage of others without contributing to the shared good. To achieve the higher goal of sustainability, it is important that conflicts in the sharing economy are prevented, and a setting is achieved that allows people to easily behave in a cooperative and sustainable way. The present research examines which conflicts emerge in sharing communities (study 1) and community gardens in particular (study 2), and whether regulation can prevent conflicts in large groups. Two exploratory studies were conducted. First, a qualitative study with consumers and non-consumers of the sharing economy revealed that regulatory systems are perceived as important for preventing the exploitation of other community members, but also that cooperation should not be enforced with strict controls and punishment. Rather, problems should be discussed in a democratic group setting, rules and goals should be set up together, and trust should be built. Second, a questionnaire study with community gardeners in Austria confirmed these results, and showed that trust is related to less conflict in community gardens, while harsh forms of regulation are related to a potential for greater conflict. Additionally, the results indicate that soft forms of regulation are related to fewer relationship and task conflicts, better conflict resolutions, a high sense of community, and greater trust in the community. We then discuss how these findings can be used to regulate sharing economy activities and give limitations and directions for future studies

The Influence of Regulation on Trust and Risk Preference in Sharing Communities

Sharing within communities has gained popularity in recent years. However, taking part in a community also comes with a certain amount of risk. This perceived amount of risk can be contained by regulations within a community as well as by potential participants’ trust in the community and the other members. We argue for a relation between regulation and the willingness to take the risk of joining a sharing community with trust as a mediator. Thereby, we distinguish between two kinds of regulation (soft and harsh regulation) and two kinds of trust (implicit and reason-based trust) on two different levels (vertical and horizontal trust). In one laboratory and one online experiment with 432 participants overall, we found that the compound of high soft and low harsh regulation increases participants’ willingness to take the risk of participation and that the effect of soft regulation is mediated mainly by vertical and horizontal reason-based trust. Based on our results, we encourage sharing communities to count on soft regulation in order to increase potential members’ trust in the community and therefore take the risk to participate

Cell-type specificity of genomic imprinting in cerebral cortex

In mammalian genomes, a subset of genes is regulated by genomic imprinting, resulting in silencing of one parental allele. Imprinting is essential for cerebral cortex development, but prevalence and functional impact in individual cells is unclear. Here, we determined allelic expression in cortical cell types and established a quantitative platform to interrogate imprinting in single cells. We created cells with uniparental chromosome disomy (UPD) containing two copies of either the maternal or the paternal chromosome; hence, imprinted genes will be 2-fold overexpressed or not expressed. By genetic labeling of UPD, we determined cellular phenotypes and transcriptional responses to deregulated imprinted gene expression at unprecedented single-cell resolution. We discovered an unexpected degree of cell-type specificity and a novel function of imprinting in the regulation of cortical astrocyte survival. More generally, our results suggest functional relevance of imprinted gene expression in glial astrocyte lineage and thus for generating cortical cell-type diversity

China neemt (Volvo) over

De gebeurtenissen sinds de overname van Volvo Cars door het Chinese Geely in 2010 tarten soms de verbeelding, alleszins voor de gemiddelde leek. In dit artikel zal worden aangetoond dat de Chinezen echter een zeer doordachte strategie gebruiken om hun geopolitieke en –economische doelen te verwezenlijken

Chromatin mapping and single-cell immune profiling define the temporal dynamics of ibrutinib response in CLL

The Bruton tyrosine kinase (BTK) inhibitor ibrutinib provides effective treatment for patients with chronic lymphocytic leukemia (CLL), despite extensive heterogeneity in this disease. To define the underlining regulatory dynamics, we analyze high-resolution time courses of ibrutinib treatment in patients with CLL, combining immune-phenotyping, single-cell transcriptome profiling, and chromatin mapping. We identify a consistent regulatory program starting with a sharp decrease of NF-kappa B binding in CLL cells, which is followed by reduced activity of lineage-defining transcription factors, erosion of CLL cell identity, and acquisition of a quiescence-like gene signature. We observe patient-to-patient variation in the speed of execution of this program, which we exploit to predict patient-specific dynamics in the response to ibrutinib based on the pre-treatment patient samples. In aggregate, our study describes time-dependent cellular, molecular, and regulatory effects for therapeutic inhibition of B cell receptor signaling in CLL, and it establishes a broadly applicable method for epigenome/transcriptome-based treatment monitoring

The Early Stages and Natural History of Antirrhea Adoptive Porphyrosticta (Watkins, 1928) in Eastern Ecuador (Lepidoptera: Nymphalidae: Morphinae)

Here we describe the immature stages and ecological associations of Antirrhea adoptiva porphyrosticta Watkins, 1928 (Lepidoptera:Nymphalidae:Morphinae). The cloud forest bamboo, Chusquea scandens Kunth (Bambusoidea: Poaceae), serves as the larval food plant for this butterfly in eastern Ecuador, the first hostplant record for Antirrhea outside the family Arecaceae. The larvae of A. adoptiva porphyrosticta are superficially similar to those of other Antirrhea species. We also provide observations on adult and larval behavior. Caterpillars of this butterfly species are parasitized by tachinid flies, as well as by Ichneumonidae and a newly described braconid wasp

Complex Interplay Between MAZR and Runx3 Regulates the Generation of Cytotoxic T Lymphocyte and Memory T Cells

The BTB zinc finger transcription factor MAZR (also known as PATZ1) controls, partially in synergy with the transcription factor Runx3, the development of CD8 lineage T cells. Here we explored the role of MAZR as well as combined activities of MAZR/Runx3 during cytotoxic T lymphocyte (CTL) and memory CD8(+) T cell differentiation. In contrast to the essential role of Runx3 for CTL effector function, the deletion of MAZR had a mild effect on the generation of CTLs in vitro. However, a transcriptome analysis demonstrated that the combined deletion of MAZR and Runx3 resulted in much more widespread downregulation of CTL signature genes compared to single Runx3 deletion, indicating that MAZR partially compensates for loss of Runx3 in CTLs. Moreover, in line with the findings made in vitro, the analysis of CTL responses to LCMV infection revealed that MAZR and Runx3 cooperatively regulate the expression of CD8 alpha, Granzyme B and perforin in vivo. Interestingly, while memory T cell differentiation is severely impaired in Runx3-deficient mice, the deletion of MAZR leads to an enlargement of the long-lived memory subset and also partially restored the differentiation defect caused by loss of Runx3. This indicates distinct functions of MAZR and Runx3 in the generation of memory T cell subsets, which is in contrast to their cooperative roles in CTLs. Together, our study demonstrates complex interplay between MAZR and Runx3 during CTL and memory T cell differentiation, and provides further insight into the molecular mechanisms underlying the establishment of CTL and memory T cell pools

The impact of web-based and face-to-face simulation on patient deterioration and patient safety : Protocol for a multi-site multi-method design

Background: There are international concerns in relation to the management of patient deterioration which has led to a body of evidence known as the 'failure to rescue' literature. Nursing staff are known to miss cues of deterioration and often fail to call for assistance. Medical Emergency Teams (Rapid Response Teams) do improve the management of acutely deteriorating patients, but first responders need the requisite skills to impact on patient safety. Methods/design: In this study we aim to address these issues in a mixed methods interventional trial with the objective of measuring and comparing the cost and clinical impact of face-to-face and web-based simulation programs on the management of patient deterioration and related patient outcomes. The education programs, known as 'FIRST2ACT', have been found to have an impact on education and will be tested in four hospitals in the State of Victoria, Australia. Nursing staff will be trained in primary (the first 8 min) responses to emergencies in two medical wards using a face-to-face approach and in two medical wards using a web-based version FIRST2ACTWeb. The impact of these interventions will be determined through quantitative and qualitative approaches, cost analyses and patient notes review (time series analyses) to measure quality of care and patient outcomes. Discussion: In this 18 month study it is hypothesised that both simulation programs will improve the detection and management of deteriorating patients but that the web-based program will have lower total costs. The study will also add to our overall understanding of the utility of simulation approaches in the preparation of nurses working in hospital wards. (ACTRN12616000468426, retrospectively registered 8.4.2016). © 2016 The Author(s)