1,692 research outputs found

    Measurement of Linear Stark Interference in 199Hg

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    We present measurements of Stark interference in the 61S0^1S_0 \rightarrow 63P1^3P_1 transition in 199^{199}Hg, a process whereby a static electric field EE mixes magnetic dipole and electric quadrupole couplings into an electric dipole transition, leading to EE-linear energy shifts similar to those produced by a permanent atomic electric dipole moment (EDM). The measured interference amplitude, aSIa_{SI} = (aM1+aE2)(a_{M1} + a_{E2}) = (5.8 ±\pm 1.5)×109\times 10^{-9} (kV/cm)1^{-1}, agrees with relativistic, many-body predictions and confirms that earlier central-field estimates are a factor of 10 too large. More importantly, this study validates the capability of the 199^{199}Hg EDM search apparatus to resolve non-trivial, controlled, and sub-nHz Larmor frequency shifts with EDM-like characteristics.Comment: 4 pages, 4 figures, 1 table; revised in response to reviewer comment

    Improved limit on the permanent electric dipole moment of 199Hg

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    We report the results of a new experimental search for a permanent electric dipole moment of 199Hg utilizing a stack of four vapor cells. We find d(199Hg) = (0.49 \pm 1.29_stat \pm 0.76_syst) x 10^{-29} e cm, and interpret this as a new upper bound, |d(199Hg)| < 3.1 x 10^{-29} e cm (95% C.L.). This result improves our previous 199Hg limit by a factor of 7, and can be used to set new constraints on CP violation in physics beyond the standard model.Comment: 4 pages, 4 figures. additional reference, minor edits in response to reviewer comment

    Inequality, poverty and the privatization of essential services: A "systems of provision" study of water, energy and local buses in the UK

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    This paper is concerned with the distributional effects of the deregulation and privatization of essential services in Britain since the 1980s, based on a cross-sector study of water, energy and local bus transport. Our approach locates end users within the structures and processes, and prevailing narratives that underpin both production and consumption. This framework highlights the ways that the provisioning of these vital services is contested, contradictory and underpinned by power relations. We show that, at one end, investors in these sectors have made generous returns on their investments but their methods of profit maximization are often not in the public interest. Meanwhile these profits are financed by end users’ payments of bills and fares. Many lower-income households face challenges in terms of affording, and even accessing, these essential services. Regulation has failed to provide adequate social protection. We argue that adverse social outcomes emerge from systemic factors embedded in these modes of provision. A narrative of politically-neutral, technocratic solutions belies the underlying contested nature of privatized monopolistic shared essential services. Moreover, a policy preoccupation with markets and competition obscures the inequality embedded in the underlying structures and processes and undermines more collective and equitable forms of provisioning

    Endogenous fantasy and learning in digital games.

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    Many people believe that educational games are effective because they motivate children to actively engage in a learning activity as part of playing the game. However, seminal work by Malone (1981), exploring the motivational aspects of digital games, concluded that the educational effectiveness of a digital game depends on the way in which learning content is integrated into the fantasy context of the game. In particular, he claimed that content which is intrinsically related to the fantasy will produce better learning than that which is merely extrinsically related. However, this distinction between intrinsic and extrinsic (or endogenous and exogenous) fantasy is a concept that has developed a confused standing over the following years. This paper will address this confusion by providing a review and critique of the empirical and theoretical foundations of endogenous fantasy, and its relevance to creating educational digital games. Substantial concerns are raised about the empirical basis of this work and a theoretical critique of endogenous fantasy is offered, concluding that endogenous fantasy is a misnomer, in so far as the "integral and continuing relationship" of fantasy cannot be justified as a critical means of improving the effectiveness of educational digital games. An alternative perspective on the intrinsic integration of learning content is described, incorporating game mechanics, flow and representations

    How do SYMPtoms and management tasks in chronic heart failure imPACT a person's life (SYMPACT)? Protocol for a mixed-methods study.

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    AIMS: Patients with chronic heart failure (CHF) struggle to follow self-care plans, which may lead to worsening illness and poor quality of life. Burden of treatment (BoT) describes this workload and its impact on patients' lives. Suggesting the balance between a patient's treatment workload and their capability to manage it is crucial. If BoT is reduced, self-care engagement and quality of life may improve. This article describes the SYMPACT study design and methods used to explore how symptoms and management tasks impact CHF patients' lives. METHODS AND RESULTS: We used a sequential exploratory mixed-methods design to investigate the interaction between symptoms and BoT in CHF patients. CONCLUSIONS: If symptoms and BoT are intrinsically linked, then the high level of symptoms experienced by CHF patients may lead to increased treatment burden, which likely decreases patients' engagement with self-care plans. SYMPACT may identify modifiable factors to improve CHF patients' experience

    Negative emotional experiences during navigation enhance parahippocampal activity during recall of place information

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    It is known that the parahippocampal cortex is involved in object-place associations in spatial learning, but it remains unknown whether activity within this region is modulated by affective signals during navigation. Here we used fMRI to measure the neural consequences of emotional experiences on place memory during navigation. A day before scanning, participants undertook an active object location memory task within a virtual house in which each room was associated with a different schedule of task-irrelevant emotional events. The events varied in valence (positive, negative, or neutral) and in their rate of occurrence (intermittent vs. constant). On a subsequent day, we measured neural activity while participants were shown static images of the previously learned virtual environment, now in the absence of any affective stimuli. Our results showed that parahippocampal activity was significantly enhanced bilaterally when participants viewed images of a room in which they had previously encountered negatively arousing events. We conclude that such automatic enhancement of place representations by aversive emotional events serves as an important adaptive mechanism for avoiding future threats
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