891 research outputs found

    Encounters with the American Prairie: Realism, Idealism, and the Search for the Authentic Plains in the Nineteenth Century

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    The Great Plains are prevalent among the literature of the nineteenth century, but receive hardly a single representation among the landscapes of the Hudson River School. This is certainly surprising; the public was teeming with interest in the Midwest and yet the principal landscape painters who aimed to represent and idealize a burgeoning America offered hardly a glance past the Mississippi River. This geographical silence is the result of a tension between idealistic and empirical representations of the land, one echoed in James Fenimore Cooper’s The Prairie, Washington Irving’s A Tour on the Prairies, and Margaret Fuller’s Summer on the Lakes, in 1843. Margaret Fuller’s more physical and intimate Transcendentalism unifies this tension in a manner that heralds the rise of the Luminists and the plains-scapes of Worthington Whittredge

    An Analysis of the Reconceptualizing the Achieving Success Everyday Group Counseling Model

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    This article provides an evaluation of Steen et al.’s (2023) systematic review of group counseling interventions with Black male students. The article highlights strengths of the review including the effort to center the specific and unique needs of Black male students, the avoidance of comparative frameworks, and the use of critical race theory as an organizing principle so researchers do not problematize Black boys, the social and cultural heterogeneity of Black boys. Recommendations for future research include the consideration of students’ intersectional identities and studies that exhibit more methodological rigor

    Acceptor-like deep level defects in ion-implanted ZnO

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    N-type ZnO samples have been implanted with MeV Zn⁺ ions at room temperature to doses between 1×10⁸ and 2×10¹⁰cm⁻², and the defect evolution has been studied by capacitance-voltage and deep level transient spectroscopy measurements. The results show a dose dependent compensation by acceptor-like defects along the implantation depth profile, and at least four ion-induced deep-level defects arise, where two levels with energy positions of 1.06 and 1.2 eV below the conduction band increase linearly with ion dose and are attributed to intrinsic defects. Moreover, a re-distribution of defects as a function of depth is observed already at temperatures below 400 K.This work was supported by the Norwegian Research Council through the Frienergi program and the Australian Research Council through the Discovery projects program

    Assessing the reproducibility of discriminant function analyses.

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    Data are the foundation of empirical research, yet all too often the datasets underlying published papers are unavailable, incorrect, or poorly curated. This is a serious issue, because future researchers are then unable to validate published results or reuse data to explore new ideas and hypotheses. Even if data files are securely stored and accessible, they must also be accompanied by accurate labels and identifiers. To assess how often problems with metadata or data curation affect the reproducibility of published results, we attempted to reproduce Discriminant Function Analyses (DFAs) from the field of organismal biology. DFA is a commonly used statistical analysis that has changed little since its inception almost eight decades ago, and therefore provides an opportunity to test reproducibility among datasets of varying ages. Out of 100 papers we initially surveyed, fourteen were excluded because they did not present the common types of quantitative result from their DFA or gave insufficient details of their DFA. Of the remaining 86 datasets, there were 15 cases for which we were unable to confidently relate the dataset we received to the one used in the published analysis. The reasons ranged from incomprehensible or absent variable labels, the DFA being performed on an unspecified subset of the data, or the dataset we received being incomplete. We focused on reproducing three common summary statistics from DFAs: the percent variance explained, the percentage correctly assigned and the largest discriminant function coefficient. The reproducibility of the first two was fairly high (20 of 26, and 44 of 60 datasets, respectively), whereas our success rate with the discriminant function coefficients was lower (15 of 26 datasets). When considering all three summary statistics, we were able to completely reproduce 46 (65%) of 71 datasets. While our results show that a majority of studies are reproducible, they highlight the fact that many studies still are not the carefully curated research that the scientific community and public expects

    Journal Staff

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    The aluminum–zinc-vacancy (Al Zn −V Zn ) complex is identified as one of the dominant defects in Al-containing n -type ZnO after electron irradiation at room temperature with energies above 0.8 MeV. The complex is energetically favorable over the isolated V Zn , binding more than 90% of the stable V Zn ’s generated by the irradiation. It acts as a deep acceptor with the (0/− ) energy level located at approximately 1 eV above the valence band. Such a complex is concluded to be a defect of crucial and general importance that limits the n -type doping efficiency by complex formation with donors, thereby literally removing the donors, as well as by charge compensation

    Ab initio data-analytics study of carbon-dioxide activation on semiconductor oxide surfaces

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    The excessive emissions of carbon dioxide (CO2) into the atmosphere threaten to shift the CO2 cycle planet-wide and induce unpredictable climate changes. Using artificial intelligence (AI) trained on high-throughput first principles based data for a broad family of oxides, we develop a strategy for a rational design of catalytic materials for converting CO2 to fuels and other useful chemicals. We demonstrate that an electron transfer to the π-antibonding orbital of the adsorbed molecule and the associated bending of the initially linear molecule, previously proposed as the indicator of activation, are insufficient to account for the good catalytic performance of experimentally characterized oxide surfaces. Instead, our AI model identifies the common feature of these surfaces in the binding of a molecular O atom to a surface cation, which results in a strong elongation and therefore weakening of one molecular C-O bond. This finding suggests using the C-O bond elongation as an indicator of CO2 activation. Based on these findings, we propose a set of new promising oxide-based catalysts for CO2 conversion, and a recipe to find more

    Hydrogen induced optically-active defects in silicon photonic nanocavities

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    This work was supported by Era-NET NanoSci LECSIN project coordinated by F. Priolo, by the Italian Ministry of University and Research, FIRB contract No. RBAP06L4S5 and by the EPSRC UKSp project. Partial financial support by the Norwegian Research Council is also acknowledged.We demonstrate intense room temperature photoluminescence (PL) from optically active hydrogen- related defects incorporated into crystalline silicon. Hydrogen was incorporated into the device layer of a silicon on insulator (SOI) wafer by two methods: hydrogen plasma treatment and ion implantation. The room temperature PL spectra show two broad PL bands centered at 1300 and 1500 nm wavelengths: the first one relates to implanted defects while the other band mainly relates to the plasma treatment. Structural characterization reveals the presence of nanometric platelets and bubbles and we attribute different features of the emission spectrum to the presence of these different kind of defects. The emission is further enhanced by introducing defects into photonic crystal (PhC) nanocavities. Transmission electron microscopy analyses revealed that the isotropicity of plasma treatment causes the formation of a higher defects density around the whole cavity compared to the ion implantation technique, while ion implantation creates a lower density of defects embedded in the Si layer, resulting in a higher PL enhancement. These results further increase the understanding of the nature of optically active hydrogen defects and their relation with the observed photoluminescence, which will ultimately lead to the development of intense and tunable crystalline silicon light sources at room temperature.Publisher PDFPeer reviewe

    Editorial: Ethics, Values, and Designer Responsibility

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    As we rely upon increasingly complex sociotechnical systems to support ourselves and, by extension, the structures of society, it becomes yet more important to consider how ethics and values intertwine in design activity. Numerous methods that address issues related to ethics and value-centeredness in design activity exist, but it is unclear what role the design research and practice communities should play in shaping the future of these design approaches. Importantly, how might researchers and practitioners become more aware of the normative assumptions that underlie both their design activity and the design artifacts that result
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