179 research outputs found

    Evolution from a molecular Rydberg gas to an ultracold plasma in a seeded supersonic expansion of NO

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    We report the spontaneous formation of a plasma from a gas of cold Rydberg molecules. Double-resonant laser excitation promotes nitric oxide, cooled to 1 K in a seeded supersonic molecular beam, to single Rydberg states extending as deep as 80 cm−1^{-1} below the lowest ionization threshold. The density of excited molecules in the illuminated volume is as high as 1 x 1013^{13} cm−3^{-3}. This population evolves to produce prompt free electrons and a durable cold plasma of electrons and intact NO+^{+} ions.Comment: 4 pages (two column) 3 figures; smaller figure files, corrected typo

    On the formation and decay of a molecular ultracold plasma

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    Double-resonant photoexcitation of nitric oxide in a molecular beam creates a dense ensemble of 50f(2)50f(2) Rydberg states, which evolves to form a plasma of free electrons trapped in the potential well of an NO+^+ spacecharge. The plasma travels at the velocity of the molecular beam, and, on passing through a grounded grid, yields an electron time-of-flight signal that gauges the plasma size and quantity of trapped electrons. This plasma expands at a rate that fits with an electron temperature as low as 5 K, colder that typically observed for atomic ultracold plasmas. The recombination of molecular NO+^+ cations with electrons forms neutral molecules excited by more than twice the energy of the NO chemical bond, and the question arises whether neutral fragmentation plays a role in shaping the redistribution of energy and particle density that directs the short-time evolution from Rydberg gas to plasma. To explore this question, we adapt a coupled rate-equations model established for atomic ultracold plasmas to describe the energy-grained avalanche of electron-Rydberg and electron-ion collisions in our system. Adding channels of Rydberg predissociation and two-body, electron- cation dissociative recombination to the atomic formalism, we investigate the kinetics by which this relaxation distributes particle density and energy over Rydberg states, free electrons and neutral fragments. The results of this investigation suggest some mechanisms by which molecular fragmentation channels can affect the state of the plasma

    Acceptability of Specialist Psychotherapy with Emotion for Anorexia in Kent and Sussex (SPEAKS): A novel intervention for anorexia nervosa

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    Investigate the acceptability of Specialist Psychotherapy with Emotion for Anorexia in Kent and Sussex (SPEAKS), a novel intervention for anorexia nervosa (AN), conducted as a feasibility trial to provide an initial test of the intervention. SPEAKS therapy lasting 9-12 months was provided to 34 people with AN or atypical AN by eight specialist eating disorder therapists trained in the model across two NHS Trusts in the UK (Kent and Sussex) during a feasibility trial. All participants were offered a post-therapy interview; sixteen patients and six therapists agreed. All patient participants were adult females. Interviews were semi-structured and asked questions around individuals' experience of SPEAKS, the acceptability of the intervention and of the research methods. Interviews were analyzed using thematic analysis. Key areas explored in line with research questions led to 5 overarching themes and 14 subthemes: (1) shift in treatment focus and experience, (2) balancing resources and treatment outcomes, (3) navigating the online treatment environment, (4) therapist adaptation and professional development, and (5) research processes. SPEAKS was found to be an acceptable intervention for treating AN from the perspective of patients and therapists. The findings provide strong support for delivery of a larger scale randomized control trial. Recommendations for future improvements, particularly pertaining to therapist understanding of the treatment model are detailed, alongside broader clinical implications. We aimed to evaluate the acceptability of a new anorexia nervosa treatment called SPEAKS. Interviews were conducted with patients and therapists involved in the pilot study and responses were analyzed. Results showed that both patients and therapists found SPEAKS to be an acceptable treatment for anorexia nervosa. The study suggests that SPEAKS meets the criteria for moving forward with a larger trial to assess its effectiveness. [Abstract copyright: © 2024 The Authors. International Journal of Eating Disorders published by Wiley Periodicals LLC.

    Satellite Time-Dilation Measurement

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    Contains reports on four research projects.National Aeronautics and Space Administration (Contract NASw-33)Lincoln Laboratory (Purchase Order DDL B-00283)United States ArmyUnited States NavyUnited States Air Force (Contract AF19(604)-5200

    The mechanisms and processes of connection: developing a causal chain model capturing impacts of receiving recorded mental health recovery narratives.

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    BACKGROUND: Mental health recovery narratives are a core component of recovery-oriented interventions such as peer support and anti-stigma campaigns. A substantial number of recorded recovery narratives are now publicly available online in different modalities and in published books. Whilst the benefits of telling one's story have been investigated, much less is known about how recorded narratives of differing modalities impact on recipients. A previous qualitative study identified connection to the narrator and/or to events in the narrative to be a core mechanism of change. The factors that influence how individuals connect with a recorded narrative are unknown. The aim of the current study was to characterise the immediate effects of receiving recovery narratives presented in a range of modalities (text, video and audio), by establishing the mechanisms of connection and the processes by which connection leads to outcomes. METHOD: A study involving 40 mental health service users in England was conducted. Participants were presented with up to 10 randomly-selected recovery narratives and were interviewed on the immediate impact of each narrative. Thematic analysis was used to identify the mechanisms of connection and how connection leads to outcome. RESULTS: Receiving a recovery narrative led participants to reflect upon their own experiences or those of others, which then led to connection through three mechanisms: comparing oneself with the narrative and narrator; learning about other's experiences; and experiencing empathy. These mechanisms led to outcomes through three processes: the identification of change (through attending to narrative structure); the interpretation of change (through attending to narrative content); and the internalisation of interpretations. CONCLUSIONS: This is the first study to identify mechanisms and processes of connection with recorded recovery narratives. The empirically-based causal chain model developed in this study describes the immediate effects on recipients. This model can inform selection of narratives for use in interventions, and be used to support peer support workers in recounting their own recovery narratives in ways which are maximally beneficial to others

    Hale: a multi-wavelength far-infrared polarimeter for SOFIA

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    A far-infrared polarimeter, Hale, will be proposed for the next round of instruments for SOFIA. Key features are: simultaneous detection of two components of polarization; detector arrays providing >4000 pixels on the sky; and four passbands between 53 μm and 215 μm, a range characterized by strong dependence of polarization on wavelength. At 53 μm the diffraction-limited resolution, 1.2 λ/D, will be 5.2 arcsec. In all passbands the systematic errors in polarization will be Δ(P) < 0.2%, Δθ< 2 °

    Atmospheric observations consistent with reported decline in the UK’s methane emissions, 2013 – 2020

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    Atmospheric measurements can be used as a tool to evaluate national greenhouse gas inventories through inverse modelling. Using 8 years of continuous methane (CH4) concentration data, this work assesses the United Kingdom's (UK) CH4 emissions over the period 2013–2020. Using two different inversion methods, we find mean emissions of 2.10 ± 0.09 and 2.12 ± 0.26 Tg yr−1 between 2013 and 2020, an overall trend of −0.05 ± 0.01 and −0.06 ± 0.04 Tg yr−2 and a 2 %–3 % decrease each year. This compares with the mean emissions of 2.23 Tg yr−1 and the trend of −0.03 Tg yr−2 (1 % annual decrease) reported in the UK's 2021 inventory between 2013 and 2019. We examine how sensitive these estimates are to various components of the inversion set-up, such as the measurement network configuration, the prior emissions estimate, the inversion method and the atmospheric transport model used. We find the decreasing trend to be due, primarily, to a reduction in emissions from England, which accounts for 70 % of the UK CH4 emissions. Comparisons during 2015 demonstrate consistency when different atmospheric transport models are used to map the relationship between sources and atmospheric observations at the aggregation level of the UK. The posterior annual national means and negative trend are found to be consistent across changes in network configuration. We show, using only two monitoring sites, that the same conclusions on mean UK emissions and negative trend would be reached as using the full six-site network, albeit with larger posterior uncertainties. However, emissions estimates from Scotland fail to converge on the same posterior under different inversion set-ups, highlighting a shortcoming of the current observation network in monitoring all of the UK. Although CH4 emissions in 2020 are estimated to have declined relative to previous years, this decrease is in line with the longer-term emissions trend and is not necessarily a response to national lockdowns

    Crafting interactive decoration

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    © 2017 ACM. everyday artefacts. This involves adorning them with decorative patterns that enhance their beauty while triggering digital interactions when scanned with cameras. These are realized using an existing augmented reality technique that embeds computer readable codes into the topological structures of hand-drawn patterns. We describe a research through design process that engaged artisans to craft a portfolio of interactive artefacts, including ceramic bowls, embroidered gift cards, fabric souvenirs, and an acoustic guitar. We annotate this portfolio with reflections on the crafting process, revealing how artisans addressed pattern, materials, form and function, and digital mappings throughout their craft process. Further reflection on our portfolio reveals how they bridged between human and system perceptions of visual patterns and engaged in a deep embedding of digital interactions into physical materials. Our findings demonstrate the potential for interactive decoration, distilling the craft knowledge involved in creating aesthetic and functional decoration, highlight the need for transparent computer vision technologies, and raise wider issues for HCI's growing engagement with craft

    Using recorded mental health recovery narratives as a resource for others: Narrative Experiences Online (NEON) intervention development

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    Background: The internet enables sharing of narratives about health concerns on a substantial scale, and some digital health narratives have been integrated into digital health interventions. Narratives describing recovery from health problems are a focus of research, including those presented in recorded (eg, invariant) form. No clinical trial has been conducted on a web-based intervention providing access to a collection of Recorded Recovery Narratives (RRNs). Objective: This study presents knowledge produced through the development of the Narrative Experiences Online (NEON) Intervention, a web-based intervention incorporating the algorithmic recommendation of RRNs. Methods: Knowledge was gathered through knowledge integration (KI) activities. KI1 synthesized previous studies to produce the NEON Impact Model describing how accessing RRNs produces health-related outcomes. KI2 developed curation principles for the NEON Collection of RRNs through consultation with the NEON Lived Experience Advisory Panel and the curation of a preliminary collection. KI3 identified harm minimization strategies for the NEON Intervention through consultation with the NEON International Advisory Board and Lived Experience Advisory Panel. The NEON Intervention was finalized through 2 research studies (RS). In RS1, mental health service users (N=40) rated the immediate impact of randomly presented narratives to validate narrative feedback questions used to inform the recommendation algorithm. In RS2, mental health service users (n=25) were interviewed about their immediate response to a prototype of the NEON Intervention and trial procedures and then were interviewed again after 1 month of use. The usability and acceptability of the prototype and trial procedures were evaluated and refinements were made. Results: KI1 produced the NEON Impact Model, which identifies moderators (recipient and context), mechanisms of connection (reflection, comparison, learning, and empathy), processes (identification of change from narrative structure or content and internalization of observed change), and outcomes (helpful and unhelpful). KI2 identified 22 curation principles, including a mission to build a large, heterogeneous collection to maximize opportunities for connection. KI3 identified seven harm minimization strategies, including content warnings, proactive and reactive blocking of narratives, and providing resources for the self-management of emotional distress. RS1 found variation in the impact of narratives on different participants, indicating that participant-level feedback on individual narratives is needed to inform a recommender system. The order of presentation did not predict narrative feedback. RS2 identified amendments to web-based trial procedures and the NEON Intervention. Participants accessed some narratives multiple times, use reduced over the 4-week period, and narrative feedback was provided for 31.8% (105/330) of narrative accesses. Conclusions: RRNs can be integrated into web-based interventions. Evaluating the NEON Intervention in a clinical trial is feasible. The mixed methods design for developing the NEON Intervention can guide its extension to other clinical populations, the design of other web-based mental health interventions, and the development of narrative-based interventions in mental health
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