Local Density of States at Metal-Semiconductor Interfaces: An Atomic Scale Study

We investigate low temperature grown, abrupt, epitaxial, nonintermixed, defect-free n-type and p-type Fe/GaAs(110) interfaces by cross-sectional scanning tunneling microscopy and spectroscopy with atomic resolution. The probed local density of states shows that a model of the ideal metal-semiconductor interface requires a combination of metal-induced gap states and bond polarization at the interface which is nicely corroborated by density functional calculations. A three-dimensional finite element model of the space charge region yields a precise value for the Schottky barrier height

Eleventh Amendment: A Move towards Simplicity in the Test for Immunity

The Eleventh Amendment was ratified in response to Chisholm v. Georgia, which held that the language of Article III, § 2 makes a state amenable to suit in federal court by citizens of another state.\u27 By its express terms, Eleventh Amendment immunity is only available to states being sued by citizens of other states.\u27 Since its enactment some two centuries ago, the Amendment has been interpreted to extend to a state being sued by its own citizens and to agencies which constitute an arm-of-the- state. This note examines the Supreme Court\u27s restatement of the test for immunity and its impact in future Eleventh Amendment cases

Father Death and Adult Success Among the Tsimane: Implications for Marriage and Divorce

Human fathers are heavily involved in the rearing of children around the world. While there is great cross-cultural variation, the father is a recognizable role in all populations. This deviates from the standard mammalian pattern of little paternal investment. A logical explanation offered early by evolutionary theorists is that human fathers evolved the capacity for paternal concern because human children are remarkably needy and impose a great encumbrance on the mother (Lancaster & Lancaster, 1983; Lovejoy, 1981). Thus, fathers have greater opportunity to enhance the wellbeing of child and mother, as there is a deeper well of need to fill. Marginal gains of family investment are thus steeper, leading to greater possibility for such returns to supersede those provided by the short-term mating strategies that are typical of most mammals. However, the numerous studies that have explored the cross-cultural impact of father presence on child survivorship report mixed results (Sear & Mace, 2008), indicating that father presence (and by assumption, investment) does not universally associate with better-off children. Fathers may also play an important role in enhancing the future competitiveness of their children by enhancing their physical condition, teaching them important skills, accumulating heritable wealth, or by building social alliances (Hewlett, 1992; Scelza, 2010). Previous studies have largely focused on the wellbeing of juvenile children, but a more complete test of the impact of paternal investment concerns its effect on the reproductive value of children, which must include adult fertility. Our goal in this paper is to fill this gap in the literature by reporting several measures of achieved success of adults based on the number of years their fathers were alive and present during their childhood. Specifically, we explore the impact of father presence on offspring height, body mass index (BMI), age of first reproduction, completed fertility for age, and number of surviving children for age. We report only one significant finding out of ten specific tests (five predictions for both men and women), thus failing to find any robust pattern of father death impacting the achieved success of adult children. Finally, we relate our findings to the nature of Tsimane marriage. Marriage in humans is often considered a means of facilitating the providing of bi-parental care (Hurtado & Hill, 1992; Lovejoy, 1981). Among the Tsimane, marriages are fairly stable, particularly after children have been born, strengthening the prediction that the presence of Tsimane fathers should be important to the success of children. We thus explore alternative explanations for the stability of Tsimane marriages by examining alternative fitness pathways and constraints experienced by Tsimane men

Ecological evaluation of restored former sewage channels in the urbanised Emscher catchment

Background My thesis aimed at the ecological evaluation of restored former sewage channels located in the highly urbanised Emscher catchment in western Germany. Prior to restoration the study streams had been used as open sewers for decades and benthic invertebrate life was not possible except for some sewage tolerant Oligochaeta. Restoration measures included the construction of underground sewers for the wastewater, the near-natural remodeling of riparian areas and of the stream bed. The unique situation in the streams of the Emscher catchment allowed to investigate the recolonisation of restored urban streams by benthic invertebrates and follow-up, the restoration success and additionally, the primary factors influencing the recolonisation. According to literature the following factors predominantly influence recolonisation: the recolonisation potential (e.g. Sundermann et al. 2011a; Tonkin et al. 2014), the species dispersal capability (Cañedo-Argüelles et al. 2015), the environmental conditions and landscape context (Hughes et al. 2008; Reynolds et al. 2013) and the succession processes (McCook 1994). These influencing factors were mainly investigated in streams of the open landscape. Therefore, their influence on the urban streams of the Emscher catchment was analysed in this thesis. For this purpose, new indicators were developed and indicators of the Water Framework Directive (WFD) were used. The WFD aims at improving the chemical and biological quality of European waters. For heavily modified water bodies, like the streams of the Emscher system, the goal is to reach the “Good Ecological Potential” until 2015 (or under certain circumstances until 2021 or 2027) (European Commission 2000). In summary, this thesis focussed on the ecological evaluation of the three main topics: First, the ecological assessment of the restored streams after restoration according to the WFD and environmental parameters influencing the Good Ecological Potential; second, the primary colonisation by benthic invertebrates after restoration and their recolonisation patterns; and third, the succession of benthic invertebrates communities and environmental parameters steering the succession process. Ecological assessment The thesis starts with an overview of the ecological status of restored sites in the whole Emscher catchment. Based on 248 taxa lists of benthic invertebrates sampled in restored sites by different sampling methods, the analysis focused on the Ecological Potential according to the requirements of the WFD. As possible explanatory parameters for the Ecological Potential, amongst others, riparian land use, stream habitats, and time since restoration were included into a PCA analysis. Almost 40 % of the sites already achieve the Good Ecological Potential at the recent sampling. Environmental parameters enhancing the probability of meeting the Good Ecological Potential include: connection of restored sites to an unmodified stream section upstream, dead wood in the stream bed, good hydro-morphological structure, deciduous riparian vegetation and unsealed surface in the stream´s surrounding, while the occurrence of iron ochre and sewage overflows located upstream of the sampling sites hinder the achievement of the Good Ecological Potential. This study also reveals that the Ecological Potential of the restored streams in the Emscher system is only indirectly determined by the factor time. Although the statistical analysis presented this factor as most influencing, in the minority of cases a parallel development of the Ecological Potential and time was found. Instead, the above mentioned environmental conditions of a restored site are of greater importance for the assessment and the achievement of the Good Ecological Potential. In conclusion, the factor “time since restoration” must be interpreted as a proxy for the overall development of the (aquatic and terrestrial) habitats in and at the restored sites. Recolonisation The recolonisation success and a good ecological assessment of the streams are amongst others dependent on recolonisation sources and the dispersal capabilities of taxa. Therefore, in a second step I analysed the recolonisation processes by benthic invertebrates. For this analysis, the case study catchment of the Boye, a 77 km² sub-catchment of the Emscher was chosen. This catchment has a high number of restored streams with almost the same ecological conditions as the whole Emscher catchment. In the spring 2012, seven restored sites connected to near-natural upstream sections were sampled, which were never used as sewage channels and are in good status morphologically. Furthermore, six unconnected restored sites were sampled. Restoration measures had been conducted between one and 19 years before sampling. Additionally, 21 near-natural sites within the catchment and eleven near-natural sites in neighbouring catchments were sampled. Near-natural sites were considered to be potential source sites from which benthic invertebrates might colonise the restored sites. 128 taxa were recorded and were categorised into five dispersal classes reflecting dispersal capabilities and degree of ecological specialisation, according to a literature review. Assemblages at restored sites were characterised by lower numbers of taxa and/or high abundances of hololimnic taxa and poorly dispersing winged species and by higher species numbers and abundance of strongly dispersing generalists. A recolonisation sequence was derived from the observed patterns, in which winged, strongly dispersing generalists colonised most rapidly and were followed by hololimnic species, weakly dispersing generalists and habitat specialists. Restored sites connected to near-natural upstream sections were colonised more rapidly than unconnected restored sites, particularly by habitat specialists. Almost 90 % of the recolonisation events originated from sources within a distance of 5 km. A succession from pioneer assemblages to more mature communities, which resembles that of the surrounding near-natural sites, was observed. In summary, assemblages in connected, restored sites needed 9 to 19 years to reach maturation, while the settlement of assemblages in unconnected sites are expected to require more time. Succession While successional changes of assemblages in lakes or wetlands are well documented, these processes are poorly understood in streams. Following stream restoration and primary recolonisation the benthic invertebrate assemblage is also supposed to undergo a succession, as new habitats have been generated. These successional changes are important to predict the taxonomical development, thus indirectly the development of the ecological assessment, of restored sites. Therefore, the same 13 sites in the seven restored streams as of the Boye sub-catchment in chapter 3 were investigated again in the spring 2013. For each site environmental parameters expected to steer the succession process were collected. Their influence on the inter-annual taxonomical change was tested with correlation analyses (Spearman’s rho). The 21 near-natural sites within the Boye catchment and 11 near-natural sites in neighbouring catchments sampled in 2012 served again as source sites for the analysis. Within 1 year time, the restored sites have undergone further succession, which lead to a higher resemblance of their assemblages to those of the source sites. These results were derived from similarity analyses, non-metric multidimensional scaling and therefrom developed change values, which show the taxonomical change of a site after 1 year dependent of the recolonisation sources. The assemblages of young restored sites changed more markedly than assemblages of old restored sites within the time span of 1 year. In the first years after restoration instable assemblages with high abundances of eurytopic pioneer taxa were found, while 5 years after restoration assemblages were increasingly similar to those of the source sites and mature assemblages were observed 9 to 10 years after restoration. Differences between young restored sites connected and unconnected to near-natural upstream sections were observed, suggesting a strong colonisation with organisms from upstream sections particularly in the first years. The succession towards near-natural assemblages is further supported by recolonisation sources in the surroundings, the presence of gravel/stones at the stream bottom and a low share of urban land use in the surrounding. Especially urban land use is associated with several stressors (e.g. diffuse inputs, morphological degradation, hydraulic stress) leading to unstable, less predictable and less favourable conditions. Conclusion and future prospects From the results of the first study, suggestions, as the creation/enhancement of growth of deciduous woody riparian vegetation along buffer strips of the streams, the reduction and improvement of sewage overflows, the provisioning of a connection to the streams tributaries, and active addition of dead wood to the streams, for further optimisation of the restoration of urban streams were derived. They serve as recommendations to improve restoration measures in the future. Furthermore, the second study showed that the establishment of mature habitat conditions, in particular woody riparian vegetation, is a prerequisite for the recolonisation of habitat specialists, which indicate the maturation progress of a restored site. In the planning phase of a restoration this knowledge can be used to especially create habitats in order to promote the recolonisation of sensitive species. Several streams of the Emscher catchment are still isolated after restoration and not directly connected to colonisation sources. For these streams a possible approach might be an assisted migration of invertebrates, which would not reach these streams on their own. This can probably help to reach the target assemblage and the Good Ecological Potential in due course. The results of the second and third study suggest that the invertebrate assemblages will reflect the restoration effects in sense of maturation at earliest 5 years, but more likely a decade, after restoration. Applying the “change value” used in the third study, timeframes for the monitoring of restored sites can be aligned for each river network, dependent of the recolonisation sources of the surrounding and the environmental conditions of the study streams´ catchment. My findings about succession help to set realistic goals in stream restoration. It can be detected at an early stage, whether the restoration target or the achievement of the Good Ecological Potential is realistic for a stream or not. Often, the success of a restoration measure initially does not result in the Good Ecological Potential. Nevertheless, it is important to know, whether a site has reached a “small success”, in terms of a taxonomic improvement, after a restoration measure. For this purpose, the dispersal classes of the second study can be used. The dispersal classification is transferable to other catchments and additional taxa could be classified following the described rules. As the number of taxa representing different dispersal classes is more constant than species richness or similarity patterns, dispersal classes could be used as a generic trait to analyse assemblage maturation. Small successes like the recolonisation of demanding taxa can get apparent. To better understand the processes of recolonisation and succession, long term studies, ideally also addressing population genetics, are advisable in the future

The Benefits of Outdoor Education for Students with Attention-Deficit Hyperactivity Disorder

ADHD diagnoses and pharmaceutical treatment have increased dramatically within this century. However, non-pharmaceutical treatments have not reflected this increase. One area where those diagnosed often struggle the most is within academic settings. This study argues for the benefit of outdoor education for students with ADHD, and suggests the importance of future research on this topic. In this study I examine the recent history of ADHD and evaluate trends in treatment, particularly green space as a form of treatment. These studies show both immediate and long-term benefits within a variety of settings. Within these studies, I identified a research gap in outdoor treatment within school settings. As well, I evaluate several studies of outdoor education within neurotypical populations and draw connections between the benefits found and how they would meet the needs of ADHD students. Examples include increases in self-regulation, self-efficacy, positive social interactions, and focus: areas of struggle for ADHD students. Given the benefit of nature education in a variety of settings as well as the specific benefits outdoor education provides to students (increases in self-regulation, self-efficacy, positive social interactions, and focus), I argue that we have sufficient evidence to suggest that outdoor education would benefit students with ADHD

Anonymity versus Privacy in the Dictator Game: Revealing Donor Decisions to Recipients Does Not Substantially Impact Donor Behavior

Anonymity is often offered in economic experiments in order to eliminate observer effects and induce behavior that would be exhibited under private circumstances. However, anonymity differs from privacy in that interactants are only unaware of each others' identities, while having full knowledge of each others' actions. Such situations are rare outside the laboratory and anonymity might not meet the requirements of some participants to psychologically engage as if their actions were private. In order to explore the impact of a lack of privacy on prosocial behaviors, I expand on a study reported in Dana et al. (2006) in which recipients were left unaware of the Dictator Game and given donations as “bonuses” to their show-up fees for other tasks. In the current study, I explore whether differences between a private Dictator Game (sensu Dana et al. (2006)) and a standard anonymous one are due to a desire by dictators to avoid shame or to pursue prestige. Participants of a Dictator Game were randomly assigned to one of four categories—one in which the recipient knew of (1) any donation by an anonymous donor (including zero donations), (2) nothing at all, (3) only zero donations, and (4) and only non-zero donations. The results suggest that a lack of privacy increases the shame that selfish-acting participants experience, but that removing such a cost has only minimal effects on actual behavior.The open access fee for this work was funded through the Texas A&M University Open Access to Knowledge (OAK) Fund

Analyses for identification of interacting proteins of the molybdenum insertase Cnx1 from Arabidopsis thaliana

Der Molybdäncofaktor ist essentieller Bestandteil aller eukaryotischen Molybdoenzyme. In A. thaliana vermittelt das Cnx1-Protein die Molybdän-Übertragung auf Molybdopterin. Anhand der Homologie zum humanen Gephyrin, das zahlreiche Protein-Wechselwirkungen eingeht, wurde auf das Vorhandensein unbekannter Cnx1-Interaktionspartner geschlossen. Die vorliegende Arbeit war auf die Detektion von Proteinen fokussiert, die als Liganden an die pflanzliche Molybdän-Insertase binden. Als konservierte Äquivalente von humanen Gephyrin-Interaktionspartnern kamen A. thaliana Profiline und die GABARAP-homologen APG8-Proteine für eine Cnx1-Wechselwirkung in Frage. Hinsichtlich einer möglichen Cnx1-Profilin-Bindung konnten jedoch keine eindeutigen Ergebnisse erzielt werden. Im Falle der neun APG8-Proteine ergaben sich aufgrund biochemischer Ansätze für APG8g, h und i Hinweise auf eine Interaktion mit Cnx1. Zur Suche nach neuen Interaktionspartnern wurde das USPS-System für eine Cnx1-Bait-Fusion etabliert. Das Screening einer A. thaliana cDNA-Bank resultierte in der Identifizierung von fünf Proteinen, die potentiell mit der pflanzlichen Molybdän-Insertase in Wechselwirkung stehen. Mit der putativen Nukleotid-Hydrolase HIT konnte ein Protein bestimmt werden, für das eine Cnx1-Interaktion sehr wahrscheinlich ist. Weiterhin sprechen mehrere Anhaltspunkte für eine Cnx1-Wechselwirkung der Thioredoxine TRX H2/H3, des putativen Urease Hilfs-Proteins UreG sowie der Adenin Phosphoribosyltransferase APRT1. In Form des möglicherweise an Cnx1 bindenden putativen Kupfer-Chaperons CCH ergab sich eine potentielle Verbindung zur Umsetzung von Kupfer-Molybdopterin im dritten Schritt der Moco-Biosynthese und somit ein neuer Hinweis auf eine Vernetzung von Molybdän- und Kupfer-Stoffwechsel. Durch die Identifizierung neuer putativer Cnx1-Interaktionspartner konnte die Grundlage für Experimente zur endgültigen Verifizierung der Wechselwirkungen sowie zu deren funktioneller Charakterisierung geschaffen werden.The molybdenum cofactor is essential compound of all eukaryotic molybdoenzymes. In A. thaliana the Cnx1 protein catalyzes the molybdenum transfer to molybdopterin. According to the homology to its human counterpart Gephyrin that undergoes several protein interactions, the presence of yet unknown Cnx1 binding proteins was proposed. The present work was focussed on the detection of proteins being ligands of the plant molybdenum insertase. As conserved equivalents of human Gephyrin binding proteins, A. thaliana Profilins and the GABARAP-homologous APG8 proteins were considered to putatively interact with Cnx1. Nevertheless, no consistent results could be achieved in case of assumed Cnx1-Profilin binding. Regarding the nine APG8 proteins, evidences for Cnx1 interactions of APG8g, h and i were obtained using biochemical approaches. In order to search for novel Cnx1 ligands, the USPS system was established for a Cnx1 bait fusion. Screening of an A. thaliana cDNA library resulted in the identification of five proteins putatively interacting with the plant molybdenum insertase. In case of the putative Nucleotide Hydrolase HIT, a protein could be determined that is very likely binding to Cnx1. Moreover, several results were found indicating towards a Cnx1 interaction of Thioredoxins TRX H2/H3, the putative Urease accessory protein UreG and the Adenine Phosphoribosyltransferase APRT1. The possibly Cnx1 binding copper chaperone CCH provides a putative connection to the turnover of copper molybdopterin within the third step of moco biosynthesis and can therefor considered to present new evidence for a linkage between molybdenum and copper metabolism. By the identification of novel putative Cnx1 ligands, the base for further approaches could be generated in order to finally verify those interactions and to investigate and characterize their functional implications