2,464 research outputs found

    A magnetic instability of the non-Abelian Sakai-Sugimoto model

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    In this follow-up paper of 1105.2217 we further discuss the occurrence of a magnetically induced tachyonic instability of the rho meson in the two-flavour Sakai-Sugimoto model, uplifting two remaining approximations in the previous paper. That is, firstly, the magnetically induced splitting of the branes is now taken into account, evaluating without approximations the symmetrized trace which enters in the non-Abelian Dirac-Born-Infeld (DBI) action. This leads to an extra mass generating effect for the charged heavy-light rho meson through a holographic Higgs mechanism. Secondly, we compare the results in the approximation to second order in the field strength to the results using the full DBI-action. Both improvements cause an increase of the critical magnetic field for the onset of rho meson condensation. In addition, the stability in the scalar sector in the presence of the magnetic field is discussed.Comment: 42 pages, v2: version accepted for publication in JHE

    Entanglement Dynamics in 2D CFT with Boundary: Entropic origin of JT gravity and Schwarzian QM

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    We study the dynamics of the geometric entanglement entropy of a 2D CFT in the presence of a boundary. We show that this dynamics is governed by local equations of motion, that take the same form as 2D Jackiw-Teitelboim gravity coupled to the CFT. If we assume that the boundary has a small thickness ϵ\epsilon and constant boundary entropy, we derive that its location satisfies the equations of motion of Schwarzian quantum mechanics with coupling constant C=cϵ/12πC = {c \epsilon}/{12\pi}. We rederive this result via energy-momentum conservation.Comment: 6 pages, 2 figure

    The relationship between self-blame for the onset of a chronic physical health condition and emotional distress : a systematic literature review

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    Objective: Past literature presents contrasting perspectives regarding the potential influence of self-blame on adjustment to illness. This systematic literature review aimed to summarise findings from all investigations to date that have explored the relationship between self-blame for the onset of a chronic physical health condition and emotional distress. Method: Between November 2014 and February 2015 electronic databases were searched for relevant literature. Only those studies which assessed self-blame directly and related specifically to illness onset were included within the review. The methodological and reporting quality of all eligible articles was assessed and themes within the findings were discussed using a narrative synthesis approach. Results: The majority of studies found self-blame to be associated with increased distress. However, several concerns with the quality of the reviewed articles may undermine the validity of their conclusions. Conclusions: It is important for professionals supporting people with chronic physical health conditions to have an understanding of how of self-critical causal attributions might relate to emotional distress. Further research is required to understand the concept of self-blame, the factors that may encourage this belief and to develop reliable and valid measures of this experience

    Cross-layer framework and optimization for efficient use of the energy budget of IoT Nodes

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    Both physical and MAC-layer need to be jointly optimized to maximize the autonomy of IoT devices. Therefore, a cross-layer design is imperative to effectively realize Low Power Wide Area networks (LPWANs). In the present paper, a cross-layer assessment framework including power modeling is proposed. Through this simulation framework, the energy consumption of IoT devices, currently deployed in LoRaWAN networks, is evaluated. We demonstrate that a cross-layer approach significantly improves energy efficiency and overall throughput. Two major contributions are made. First, an open-source LPWAN assessment framework has been conceived. It allows testing and evaluating hypotheses and schemes. Secondly, as a representative case, the LoRaWAN protocol is assessed. The findings indicate how a cross-layer approach can optimize LPWANs in terms of energy efficiency and throughput. For instance, it is shown that the use of larger payloads can reduce up to three times the energy consumption on quasi-static channels yet may bring an energy penalty under adverse dynamic conditions

    Segmented Strings in AdS3AdS_3

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    We study segmented strings in flat space and in AdS3AdS_3. In flat space, these well known classical motions describe strings which at any instant of time are piecewise linear. In AdS3AdS_3, the worldsheet is composed of faces each of which is a region bounded by null geodesics in an AdS2AdS_2 subspace of AdS3AdS_3. The time evolution can be described by specifying the null geodesic motion of kinks in the string at which two segments are joined. The outcome of collisions of kinks on the worldsheet can be worked out essentially using considerations of causality. We study several examples of closed segmented strings in AdS3AdS_3 and find an unexpected quasi-periodic behavior. We also work out a WKB analysis of quantum states of yo-yo strings in AdS3AdS_3 and find a logarithmic term reminiscent of the logarithmic twist of string states on the leading Regge trajectory.Comment: 38 pages, 5 figure

    Between Tradition and Prophecy: The Impact of the Personality of Chiara Lubich

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    How does change occur in society? How does it occur in religion? A sociological approach to these questions deals with issues not addressed by historians. Is a given change primarily a question of contextual factors, or do individual personalities have an independent role in bringing about such change? The author examines the case of Chiara Lubich and the foundation of the Focolare Movement. He asks whether Chiara Lubich and the Focolare represent phenomena that cannot be entirely attributed to the normal flow of historical processes. What is the role of tradition in this story, and what stems from innovation

    An EVH1/WH1 domain as a key actor in TGFβ signalling

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    AbstractEVH1 (enabled VASP (vasodilator-stimulated protein) homology 1)/WH1 (WASP (Wiskott–Aldrich syndrome protein) homology 1) domains, present in Ena VASP and WASP, are protein interaction modules specialised in binding proline-rich ligands. An EVH1/WH1 domain is here identified in the recently cloned SMIF protein, a key protein in transforming growth factor-β (TGFβ) signalling which was not yet related to defined domains. The SMIF EVH1/WH1 domain interacts with the proline-rich Smad4 activation domain, leading to translocation of so-formed complex to the nucleus where SMIF possesses strong intrinsic TGFβ-inducible transcriptional activity. This finding highlights the pivotal role that the EVH1/WH1 family of domains play in multiple eukaryotic signal transduction pathways
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