395 research outputs found

    A personal-computer-based imaging Stokes polarimeter for solar observations

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    For measurements of vector magnetic field over solar active regions, a Stokes polarimeter for studying the polarisation profiles on selected spectral lines is described. This paper gives details of the relevant CCD imaging system and the personal computer (PC)-based acquisition, together with the image analysis techniques necessary for the task. Field trials and tests of the system are also described

    On the non-planar beta-deformed N=4 super-Yang-Mills theory

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    The beta-deformation is one of the two superconformal deformations of the N=4 super-Yang-Mills theory. At the planar level it shares all of its properties except for supersymmetry, which is broken to the minimal amount. The tree-level amplitudes of this theory exhibit new features which depart from the commonly assumed properties of gauge theories with fields in the adjoint representation. We analyze in detail complete one-loop amplitudes and a nonplanar two-loop amplitude of this theory and show that, despite having only N=1 supersymmetry, two-loop amplitudes have a further-improved ultraviolet behavior. This phenomenon is a counterpart of a similar improvement previously observed in the double-trace amplitude of the N=4 super-Yang-Mills theory at three and four loop order and points to the existence of additional structure in both the deformed and undeformed theories.Comment: 39 pages, 8 figure

    Amplifying the Security of Functional Encryption, Unconditionally

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    Security amplification is a fundamental problem in cryptography. In this work, we study security amplification for functional encryption (FE). We show two main results: 1) For any constant epsilon in (0,1), we can amplify any FE scheme for P/poly which is epsilon-secure against all polynomial sized adversaries to a fully secure FE scheme for P/poly, unconditionally. 2) For any constant epsilon in (0,1), we can amplify any FE scheme for P/poly which is epsilon-secure against subexponential sized adversaries to a fully subexponentially secure FE scheme for P/poly, unconditionally. Furthermore, both of our amplification results preserve compactness of the underlying FE scheme. Previously, amplification results for FE were only known assuming subexponentially secure LWE. Along the way, we introduce a new form of homomorphic secret sharing called set homomorphic secret sharing that may be of independent interest. Additionally, we introduce a new technique, which allows one to argue security amplification of nested primitives, and prove a general theorem that can be used to analyze the security amplification of parallel repetitions

    Maternal ethnic ancestry and adverse perinatal outcomes in New York City

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    To examine the association between narrowly defined subsets of maternal ethnicity and birth outcomes

    Hybrid-NLIE for the AdS/CFT spectral problem

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    Hybrid-NLIE equations, an alternative finite NLIE description for the spectral problem of the super sigma model of AdS/CFT and its gamma-deformations are derived by replacing the semi-infinite SU(2) and SU(4) parts of the AdS/CFT TBA equations by a few appropriately chosen complex NLIE variables, which are coupled among themselves and to the Y-functions associated to the remaining central nodes of the TBA diagram. The integral equations are written explicitly for the ground state of the gamma-deformed system. We linearize these NLIE equations, analytically calculate the first correction to the asymptotic solution and find agreement with analogous results coming from the original TBA formalism. Our equations differ substantially from the recently published finite FiNLIE formulation of the spectral problem.Comment: 63 pages, 1 figur

    In vivo serotonin 1A receptor hippocampal binding potential in depression and reported childhood adversity

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    Abstract Background Reported childhood adversity (CA) is associated with development of depression in adulthood and predicts a more severe course of illness. Although elevated serotonin 1A receptor (5-HT1AR) binding potential, especially in the raphe nuclei, has been shown to be a trait associated with major depression, we did not replicate this finding in an independent sample using the partial agonist positron emission tomography tracer [11C]CUMI-101. Evidence suggests that CA can induce long-lasting changes in expression of 5-HT1AR, and thus, a history of CA may explain the disparate findings. Methods Following up on our initial report, 28 unmedicated participants in a current depressive episode (bipolar n = 16, unipolar n = 12) and 19 non-depressed healthy volunteers (HVs) underwent [11C]CUMI-101 imaging to quantify 5-HT1AR binding potential. Participants in a depressive episode were stratified into mild/moderate and severe CA groups via the Childhood Trauma Questionnaire. We hypothesized higher hippocampal and raphe nuclei 5-HT1AR with severe CA compared with mild/moderate CA and HVs. Results There was a group-by-region effect (p = 0.011) when considering HV, depressive episode mild/moderate CA, and depressive episode severe CA groups, driven by significantly higher hippocampal 5-HT1AR binding potential in participants in a depressive episode with severe CA relative to HVs (p = 0.019). Contrary to our hypothesis, no significant binding potential differences were detected in the raphe nuclei (p -value s > 0.05). Conclusions With replication in larger samples, elevated hippocampal 5-HT1AR binding potential may serve as a promising biomarker through which to investigate the neurobiological link between CA and depression

    Quantum Symmetries and Marginal Deformations

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    We study the symmetries of the N=1 exactly marginal deformations of N=4 Super Yang-Mills theory. For generic values of the parameters, these deformations are known to break the SU(3) part of the R-symmetry group down to a discrete subgroup. However, a closer look from the perspective of quantum groups reveals that the Lagrangian is in fact invariant under a certain Hopf algebra which is a non-standard quantum deformation of the algebra of functions on SU(3). Our discussion is motivated by the desire to better understand why these theories have significant differences from N=4 SYM regarding the planar integrability (or rather lack thereof) of the spin chains encoding their spectrum. However, our construction works at the level of the classical Lagrangian, without relying on the language of spin chains. Our approach might eventually provide a better understanding of the finiteness properties of these theories as well as help in the construction of their AdS/CFT duals.Comment: 1+40 pages. v2: minor clarifications and references added. v3: Added an appendix, fixed minor typo

    Predicting recovery at home after Ambulatory Surgery

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    The correct implementation of Ambulatory Surgery must be accompanied by an accurate monitoring of the patient post-discharge state. We fit different statistical models to predict the first hours postoperative status of a discharged patient. We will also be able to predict, for any discharged patient, the probability of needing a closer follow-up, or of having a normal progress at home

    Non Inflammatory Boronate Based Glucose-Responsive Insulin Delivery Systems

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    Boronic acids, known to bind diols, were screened to identify non-inflammatory cross-linkers for the preparation of glucose sensitive and insulin releasing agglomerates of liposomes (Agglomerated Vesicle Technology-AVT). This was done in order to select a suitable replacement for the previously used cross-linker, ConcanavalinA (ConA), a lectin known to have both toxic and inflammatory effects in vivo. Lead-compounds were selected from screens that involved testing for inflammatory potential, cytotoxicity and glucose-binding. These were then conjugated to insulin-encapsulating nanoparticles and agglomerated via sugar-boronate ester linkages to form AVTs. In vitro, the particles demonstrated triggered release of insulin upon exposure to physiologically relevant concentrations of glucose (10 mmoles/L–40 mmoles/L). The agglomerates were also shown to be responsive to multiple spikes in glucose levels over several hours, releasing insulin at a rate defined by the concentration of the glucose trigger
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