688 research outputs found

    Sharpening of natural guide stars for low-order wavefront sensing using patrolling laser guide stars

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    A laser guide star (LGS) adaptive optics (AO) system generally requires additional tip/tilt information derived using a natural guide star (NGS), while multi-LGS systems will benefit from measurement of additional low-order wavefront modes using one or more NGS's. If we use AO sharpened NGS's, we can improve both the measurement accuracy and accessible sky fraction while also minimizing the observational overhead of faint NGS acquisition. Multi-object adaptive optics (MOAO) sharpening of NGS is possible where a good estimate of the NGS wavefront can be made, for example where tomographic wavefront information is available. We describe a new approach for high Strehl ratio sharpening, based on additional patrolling laser beacons, to eliminate generalized anisoplanatism and minimize tomography error in the NGS direction

    Magnetic Monopole Noise

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    Magnetic monopoles are hypothetical elementary particles exhibiting quantized magnetic charge m0=±(h/μ0e)m_0=\pm(h/\mu_0e) and quantized magnetic flux Φ0=±h/e\Phi_0=\pm h/e. A classic proposal for detecting such magnetic charges is to measure the quantized jump in magnetic flux Φ\Phi threading the loop of a superconducting quantum interference device (SQUID) when a monopole passes through it. Naturally, with the theoretical discovery that a plasma of emergent magnetic charges should exist in several lanthanide-pyrochlore magnetic insulators, including Dy2_2Ti2_2O7_7, this SQUID technique was proposed for their direct detection. Experimentally, this has proven extremely challenging because of the high number density, and the generation-recombination (GR) fluctuations, of the monopole plasma. Recently, however, theoretical advances have allowed the spectral density of magnetic-flux noise SΦ(ω,T)S_{\Phi}(\omega,T) due to GR fluctuations of ±m\pm m_* magnetic charge pairs to be determined. These theories present a sequence of strikingly clear predictions for the magnetic-flux noise signature of emergent magnetic monopoles. Here we report development of a high-sensitivity, SQUID based flux-noise spectrometer, and consequent measurements of the frequency and temperature dependence of SΦ(ω,T)S_{\Phi}(\omega,T) for Dy2_2Ti2_2O7_7 samples. Virtually all the elements of SΦ(ω,T)S_{\Phi}(\omega,T) predicted for a magnetic monopole plasma, including the existence of intense magnetization noise and its characteristic frequency and temperature dependence, are detected directly. Moreover, comparisons of simulated and measured correlation functions CΦ(t)C_{\Phi}(t) of the magnetic-flux noise Φ(t)\Phi(t) imply that the motion of magnetic charges is strongly correlated because traversal of the same trajectory by two magnetic charges of same sign is forbidden

    Internalized Consensual Non-Monogamy Negativity and Relationship Quality Among People Engaged in Polyamory, Swinging, and Open Relationships

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    Drawing on an internalized homonegativity and minority stress framework, the present study sought to address whether people engaged in consensual non-monogamy (CNM) internalize stigma toward their relationship style, and if internalized CNM negativity is associated with poorer relationship quality and functioning. We recruited a community sample of 339 people engaged in CNM (open, swinging, or polyamorous relationship) with at least two concurrent partners. Participants completed a newly developed measure of internalized CNM negativity (which assessed personal discomfort, social discomfort, and public identification) and four measures of relationship quality for each partner. Regression analyses showed that personal discomfort with CNM (e.g., wanting to change one’s relationship style or endorsing CNM as unnatural) was associated with lower satisfaction with romantic and sexual relationship agreements, global relationship satisfaction, and commitment (but not sexual satisfaction) in both concurrent relationships. The other two dimensions of internalized CNM negativity, social discomfort and public identification, were not related to relationship quality with either partner. These findings provide support for the notion that prevailing mononormativity (idealization of monogamy in society) can become applied to the self and negatively impact relationship quality. Understanding the processes in which broader societal stigma toward CNM can become internalized and affect well-being provides a new direction for research at the intersection of public health, psychology, and sexuality

    RESPOND – A patient-centred programme to prevent secondary falls in older people presenting to the emergency department with a fall: Protocol for a mixed methods programme evaluation.

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    Background Programme evaluations conducted alongside randomised controlled trials (RCTs) have potential to enhance understanding of trial outcomes. This paper describes a multi-level programme evaluation to be conducted alongside an RCT of a falls prevention programme (RESPOND). Objectives 1) To conduct a process evaluation in order to identify the degree of implementation fidelity and associated barriers and facilitators. 2) To evaluate the primary intended impact of the programme: participation in fall prevention strategies, and the factors influencing participation. 3) To identify the factors influencing RESPOND RCT outcomes: falls, fall injuries and ED re-presentations. Methods/ Design Five hundred and twenty eight community-dwelling adults aged 60–90 years presenting to two EDs with a fall will be recruited and randomly assigned to the intervention or standard care group. All RESPOND participants and RESPOND clinicians will be included in the evaluation. A mixed methods design will be used and a programme logic model will frame the evaluation. Data will be sourced from interviews, focus groups, questionnaires, clinician case notes, recruitment records, participant-completed calendars, hospital administrative datasets, and audio-recordings of intervention contacts. Quantitative data will be analysed via descriptive and inferential statistics and qualitative data will be interpreted using thematic analysis. Discussion The RESPOND programme evaluation will provide information about contextual and influencing factors related to the RCT outcomes. The results will assist researchers, clinicians, and policy makers to make decisions about future falls prevention interventions. Insights gained are likely to be transferable to preventive health programmes for a range of chronic conditions

    Sharpening of natural guide stars for low-order wavefront sensing using patrolling laser guide stars

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    A laser guide star (LGS) adaptive optics (AO) system generally requires additional tip/tilt information derived using a natural guide star (NGS), while multi-LGS systems will benefit from measurement of additional low-order wavefront modes using one or more NGS's. If we use AO sharpened NGS's, we can improve both the measurement accuracy and accessible sky fraction while also minimizing the observational overhead of faint NGS acquisition. Multi-object adaptive optics (MOAO) sharpening of NGS is possible where a good estimate of the NGS wavefront can be made, for example where tomographic wavefront information is available. We describe a new approach for high Strehl ratio sharpening, based on additional patrolling laser beacons, to eliminate generalized anisoplanatism and minimize tomography error in the NGS direction

    One-pot silyl ketene imine formation-nucleophilic addition reactions of acetonitrile with acetals and nitrones

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    Trimethylsilyl trifluoromethanesulfonate (TMSOTf) and a trialkylamine base promote the conversion of acetonitrile to its silyl ketene imine in situ when acetonitrile is employed as solvent. Residual TMSOTf acts as a Lewis acid catalyst to activate acetals and nitrones in the reaction mixture, yielding β-methoxynitriles and β-(silyloxy)aminonitriles, respectively. Some reaction products undergo elimination under the reaction conditions to provide the α,β-unsaturated nitrile directly

    Multiple guide star tomography demonstration at Palomar observatory

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    We have built and field tested a multiple guide star tomograph with four Shack-Hartmann wavefront sensors. We predict the wavefront on the fourth sensor channel estimated using wavefront information from the other three channels using synchronously recorded data. This system helps in the design of wavefront sensors for future extremely large telescopes that will use multi conjugate adaptive optics and multi object adaptive optics. Different wavefront prediction algorithms are being tested with the data obtained. We describe the system, its current capabilities and some preliminary results

    \u27It promoted a positive culture around falls prevention\u27: staff response to a patient education programme—a qualitative evaluation

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    Objectives: The purpose of this study was to understand how staff responded to individualized patient falls prevention education delivered as part of a cluster randomised trial, including how they perceived the education contributed to falls prevention on their wards. Design: A qualitative explanatory study. Methods: 5 focus groups were conducted at participatory hospital sites. The purposive sample of clinical staff (including nurses, physiotherapists and quality improvement staff ) worked on aged care rehabilitation wards when a cluster randomised trial evaluating a patient education programme was conducted. During the intervention period, an educator, who was a trained health professional and not a member of staff, provided individualised falls prevention education to patients with good levels of cognition (Mini-Mental State Examination \u3e23/30). Clinical staff were provided with training to support the programme and their feedback was sought after the trial concluded, to understand how they perceived the programme impacted on falls prevention. Data were thematically analysed using NVivo qualitative data analysis software. Results: 5 focus groups were conducted at different hospitals (n=30 participants). Staff perceived that the education created a positive culture around falls prevention and further, facilitated teamwork, whereby patients and staff worked together to address falls prevention. The educator was perceived to be a valuable member of the team. Staff reported that they developed increased knowledge and awareness about creating a safe ward environment. Patients being proactive and empowered to engage in falls prevention strategies, such as ringing the bell for assistance, was viewed as supporting staff falls prevention efforts and motivating staff to change practice. Conclusions: Staff responded positively to patient falls prevention education being delivered on their wards. Providing individualised patient education to older patients with good levels of cognition can empower staff and patients to work as a team to address falls prevention on hospital rehabilitation wards

    Educators’ perspectives about how older hospital patients can engage in a falls prevention education programme: a qualitative process evaluation

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    Objectives - Falls are the most frequent adverse event reported in hospitals. Patient and staff education delivered by trained educators significantly reduced falls and injurious falls in an older rehabilitation population. The purpose of the study was to explore the educators’ perspectives of delivering the education and to conceptualise how the programme worked to prevent falls among older patients who received the education. Design - A qualitative exploratory study. Methods - Data were gathered from three sources: conducting a focus group and an interview (n=10 educators), written educator notes and reflective researcher field notes based on interactions with the educators during the primary study. The educators delivered the programme on eight rehabilitation wards for periods of between 10 and 40 weeks. They provided older patients with individualised education to engage in falls prevention and provided staff with education to support patient actions. Data were thematically analysed and presented using a conceptual framework. Results - Falls prevention education led to mutual understanding between staff and patients which assisted patients to engage in falls prevention behaviours. Mutual understanding was derived from the following observations: the educators perceived that they could facilitate an effective three-way interaction between staff actions, patient actions and the ward environment which led to behaviour change on the wards. This included engaging with staff and patients, and assisting them to reconcile differing perspectives about falls prevention behaviours. Conclusions - Individualised falls prevention education effectively provides patients who receive it with the capability and motivation to develop and undertake behavioural strategies that reduce their falls, if supported by staff and the ward environment
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