978 research outputs found

    Normal redefined: Exploring decontextualization of lorises (Nycticebus & Xanthonycticebus spp.) on social media platforms

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    Introduction: Decontextualization is a concept from psychology whereby new words are learned outside of the context of the here-and-now. Decontextualized language is used for discussing abstract concepts and is crucial to the development of academic language. When it comes to images, a dearth of context can lead to a lack of clarity, such as the use of ambiguous decontextualized images in environmental communication, leading to the promotion of greenwashing. Here we refer to decontextualization as the removal of wildlife from their wild ecological context. Images and videos of globally threatened species are increasingly popular on social media. Showing such taxa alongside humans may impact public perceptions of their abundance and need for conservation and can increase illegal trade. One group of animals that are particularly popular on social media platforms are the slow and pygmy lorises (Nycticebus spp., Xanthonycticebus spp.). Methods: Here, we examined 100 videos from three popular social media platforms (YouTube, TikTok, and Giphy) to calculate how often and in which ways these videos remove slow lorises from their natural ecological and behavioural context. We also examined views and likes to determine viewer engagement trends. We used relevant content from each site to assess the presence of decontextualization using five conditions. Results: In all but two videos, conditions of decontextualization were present and 77% of all videos had four to five conditions of decontextualization. Using Spearman correlation, we found a significant effect of decontextualization scores on the number of views and likes for YouTube and TikTok videos. Views were significantly higher when videos presented animals in anthropogenic settings (i.e., in human-made structures or in proximity of human artefacts). Additionally, views on TikTok and YouTube were significantly higher when animals displayed signs of stress or ill health and when they were in unnatural conditions. Discussion: Our case study of lorises provides an example of the danger of decontextualizing wild animals on social media. Public preference for imagery where animals are neglected is indicative that better guidelines need to be put in place and policed by social media platforms. Additionally, conservationists need to develop strategies to promote wild imagery and further explore decontextualization if we are to understand and address the drivers of the rampant illegal wildlife trade online

    Kz selective scattering within quasiparticle interference measurements of FeSe

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    Quasiparticle interference (QPI) provides a wealth of information relating to the electronic structure of a material. However, it is often assumed that this information is constrained to two-dimensional electronic states. We show that this is not necessarily the case. For FeSe, a system dominated by surface defects, we show that it is actually all electronic states with negligible group velocity in the z axis that are contained within the experimental data. By using a three-dimensional tight-binding model of FeSe, fit to photoemission measurements, we directly reproduce the experimental QPI scattering dispersion, within a T-matrix formalism, by including both kz=0 and kz=π electronic states. This result unifies both tunnelling based and photoemission based experiments on FeSe and highlights the importance of kz within surface sensitive measurements of QPI.Publisher PDFPeer reviewe

    FeSe and the missing electron pocket problem

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    LR acknowledges funding from the Royal Commission for the Exhibition 1851.The nature and origin of electronic nematicity remains a significant challenge in our understanding of the iron-based superconductors. This is particularly evident in the iron chalcogenide, FeSe, where it is currently unclear how the experimentally determined Fermi surface near the M point evolves from having two electron pockets in the tetragonal state, to exhibiting just a single electron pocket in the nematic state. This has posed a major theoretical challenge, which has become known as the missing electron pocket problem of FeSe, and is of central importance if we wish to uncover the secrets behind nematicity and superconductivity in the wider iron-based superconductors. Here, we review the recent experimental work uncovering this nematic Fermi surface of FeSe from both ARPES and STM measurements, as well as current theoretical attempts to explain this missing electron pocket of FeSe, with a particular focus on the emerging importance of incorporating the dxy orbital into theoretical descriptions of the nematic state. Furthermore, we will discuss the consequence this missing electron pocket has on the theoretical understanding of superconductivity in this system and present several remaining open questions and avenues for future research.Publisher PDFPeer reviewe

    Revealing the single electron pocket of FeSe in a single orthorhombic domain

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    Authors acknowledge Diamond Light Source for time on beamline I05-ARPES under Proposal SI23890. L.C.R. acknowledges funding from the Royal Commission for the Exhibition of 1851.We measure the electronic structure of FeSe from within individual orthorhombic domains. Enabled by an angle-resolved photoemission spectroscopy beamline with a highly focused beam spot (nano-ARPES), we identify clear stripelike orthorhombic domains in FeSe with a length scale of approximately 1-5 μm. Our photoemission measurements of the Fermi surface and band structure within individual domains reveal a single electron pocket at the Brillouin zone corner. This result provides clear evidence for a one-electron-pocket electronic structure of FeSe, observed without the application of uniaxial strain, and calls for further theoretical insight into this unusual Fermi surface topology. Our results also showcase the potential of nano-ARPES for the study of correlated materials with local domain structures.Publisher PDFPeer reviewe

    Collective modes and sound propagation in a p-wave superconductor: Sr2_2RuO4_4

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    There are five distinct collective modes in the recently discovered p-wave superconductor Sr2_2RuO4_4; phase and amplitude modes of the order parameter, clapping mode (real and imaginary), and spin wave. The first two modes also exist in the ordinary s-wave superconductors, while the clapping mode with the energy 2Δ(T)\sqrt{2} \Delta(T) is unique to Sr2_2RuO4_4 and couples to the sound wave. Here we report a theoretical study of the sound propagation in a two dimensional p-wave superconductor. We identified the clapping mode and study its effects on the longitudinal and transverse sound velocities in the superconducting state. In contrast to the case of 3^3He, there is no resonance absorption associated with the collective mode, since in metals ω/(vFq)1\omega/(v_F |{\bf q}|) \ll 1, where vFv_F is the Fermi velocity, {\bf q} is the wave vector, and ω\omega is the frequency of the sound wave. However, the velocity change in the collisionless limit gets modified by the contribution from the coupling to the clapping mode. We compute this contribution and comment on the visibility of the effect. In the diffusive limit, the contribution from the collective mode turns out to be negligible. The behaviors of the sound velocity change and the attenuation coefficient near TcT_c in the diffusive limit are calculated and compared with the existing experimental data wherever it is possible. We also present the results for the attenuation coefficients in both of the collisionless and diffusive limits at finite temperatures.Comment: RevTex, 12 pages, 2 figures, Replaced by the published versio

    New ternary blend strategy based on a vertically self-assembled passivation layer enabling efficient and photostable inverted organic solar cells

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    Herein, a new ternary strategy to fabricate efficient and photostable inverted organic photovoltaics (OPVs) is introduced by combining a bulk heterojunction (BHJ) blend and a fullerene self-assembled monolayer (C60 -SAM). Time-of-flight secondary-ion mass spectrometry - analysis reveals that the ternary blend is vertically phase separated with the C60 -SAM at the bottom and the BHJ on top. The average power conversion efficiency - of OPVs based on the ternary system is improved from 14.9% to 15.6% by C60 -SAM addition, mostly due to increased current density (Jsc ) and fill factor -. It is found that the C60 -SAM encourages the BHJ to make more face-on molecular orientation because grazing incidence wide-angle X-ray scattering - data show an increased face-on/edge-on orientation ratio in the ternary blend. Light-intensity dependent Jsc data and charge carrier lifetime analysis indicate suppressed bimolecular recombination and a longer charge carrier lifetime in the ternary system, resulting in the enhancement of OPV performance. Moreover, it is demonstrated that device photostability in the ternary blend is enhanced due to the vertically self-assembled C60 -SAM that successfully passivates the ZnO surface and protects BHJ layer from the UV-induced photocatalytic reactions of the ZnO. These results suggest a new perspective to improve both performance and photostability of OPVs using a facial ternary method

    Electronic anisotropies revealed by detwinned angle-resolved photo-emission spectroscopy measurements of FeSe

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    We report high resolution ARPES measurements of detwinned FeSe single crystals. The application of a mechanical strain is used to promote the volume fraction of one of the orthorhombic domains in the sample, which we estimate to be 80%\% detwinned. While the full structure of the electron pockets consisting of two crossed ellipses may be observed in the tetragonal phase at temperatures above 90~K, we find that remarkably, only one peanut-shaped electron pocket oriented along the longer aa axis contributes to the ARPES measurement at low temperatures in the nematic phase, with the expected pocket along bb being not observed. Thus the low temperature Fermi surface of FeSe as experimentally determined by ARPES consists of one elliptical hole pocket and one orthogonally-oriented peanut-shaped electron pocket. Our measurements clarify the long-standing controversies over the interpretation of ARPES measurements of FeSe

    Half-quantum vortex and d-soliton in Sr2_2RuO4_4

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    Assuming that the superconductivity in Sr2_2RuO4_4 is described by a planar p-wave order parameter, we consider possible topological defects in Sr2_2RuO4_4. In particular, it is shown that both of the d^{\hat d}-soliton and half-quantum vortex can be created in the presence of the magnetic field parallel to the aa-bb plane. We discuss how one can detect the d^{\hat d}-soliton and half-quantum vortex experimentally.Comment: 8 pages, 3 figure

    The Effect of Self-Reported REM Behavior Disorder Symptomology on Intrusive Memories in Post-Traumatic Stress Disorder

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    Background: PTSD is characterised by severe sleep disturbances, which is increasingly recognised to in many cases consist of similar symptomology to sleep disorders such as REM Behaviour Disorder (RBD). The present study aimed to investigate whether different aspects of sleep quality influence intrusive memory development and whether PTSD status moderates this relationship.Participants and Methods: 34 PTSD, 52 trauma-exposed (TE) and 42 non-trauma exposed (NTE) participants completed an emotional memory task, where they viewed 60 images (20 positive, 20 negative and 20 neutral) and, two days later, reported how many intrusive memories they had of each valence category. Participants also completed three measures of sleep quality: the Pittsburgh Sleep Quality Index, the REM Behaviour Disorder Screening Questionnaire and total hours slept before each session.Results: The PTSD group reported poorer sleep quality than both TE and NTE groups on all three measures, and significantly more negative intrusive memories than the NTE group. Mediation analyses revealed that self-reported RBD symptomology before the second session mediated the relationship between PTSD status and intrusive memories. Follow-up moderation analyses revealed that self-reported RBD symptomology before the second session was only a significant predictor of intrusion in the PTSD group, though with a small effect size.Conclusions: These findings suggest that RBD symptomology is an indicator of consolidation of intrusive memories in PTSD but not trauma-exposed or healthy participants, which supports the relevance of characterising RBD in PTSD

    Comparison of CDMS [100] and [111] oriented germanium detectors

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    The Cryogenic Dark Matter Search (CDMS) utilizes large mass, 3" diameter ×\times 1" thick target masses as particle detectors. The target is instrumented with both phonon and ionization sensors and comparison of energy in each channel provides event-by-event classification of electron and nuclear recoils. Fiducial volume is determined by the ability to obtain good phonon and ionization signal at a particular location. Due to electronic band structure in germanium, electron mass is described by an anisotropic tensor with heavy mass aligned along the symmetry axis defined by the [111] Miller index (L valley), resulting in large lateral component to the transport. The spatial distribution of electrons varies significantly for detectors which have their longitudinal axis orientations described by either the [100] or [111] Miller indices. Electric fields with large fringing component at high detector radius also affect the spatial distribution of electrons and holes. Both effects are studied in a 3 dimensional Monte Carlo and the impact on fiducial volume is discussed.Comment: Low Temperature Detector 14 conference proceedings to be published in the Journal of Low Temperature Physic
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