Brief survey on computational solutions for Bayesian inference

In this paper, we present a brief review of research work attempting to tackle the issue of tractability in Bayesian inference, including an analysis of the applicability and trade-offs of each proposed solution. In recent years, the Bayesian approach has become increasingly popular, endowing autonomous systems with the ability to deal with uncertainty and incompleteness. However, these systems are also expected to be efficient, while Bayesian inference in general is known to be an NP-hard problem, making it paramount to develop approaches dealing with this complexity in order to allow the implementation of usable Bayesian solutions. Novel computational paradigms and also major developments in massively parallel computation technologies, such as multi-core processors, GPUs and FPGAs, provide us with an inkling of the roadmap in Bayesian computation for upcoming years

Extended-release niacin increases anti-apolipoprotein A-I antibodies that block the antioxidant effect of high-density lipoprotein-cholesterol: the EXPLORE clinical trial.

Extended-release niacin (ERN) is the most effective agent for increasing high-density lipoprotein-cholesterol (HDL-C). Having previously identified anti-HDL antibodies, we investigated whether ERN affected the antioxidant capacity of HDL and whether ERN was associated with the production of antibodies against HDL (aHDL) and apolipoprotein A-I (aApoA-I). METHODS: Twenty-one patients older than 18 years, with HDL-C ≤40 mg dl-1 (men) or ≤50 mg dl-1 (women) were randomly assigned to receive daily ERN (n = 10) or placebo (n = 11) for two sequential 12-week periods, with 4 weeks of wash-out before cross-over. Primary outcome was change of paraoxonase-1 (PON1) activity and secondary outcomes were changes in aHDL and aApoA-I antibodies. Clinical Trial Unique Identifier: EudraCT 2006-006889-42. RESULTS: The effect of ERN on PON1 activity was nonsignificant (coefficient estimate 20.83 U l-1 , 95% confidence interval [CI] -9.88 to 51.53; P = 0.184). ERN was associated with an increase in HDL-C levels (coefficient estimate 5.21 mg dl-1 , 95% CI 1.16 to 9.25; P = 0.012) and its subclasses HDL2 (coefficient estimate 2.46 mg dl-1 , 95% CI 0.57 to 4.34; P = 0.011) and HDL3 (coefficient estimate 2.73 mg dl-1 , 95% CI 0.47 to 4.98; P = 0.018). ERN was significantly associated with the production of aApoA-I antibodies (coefficient estimate 0.25 μg ml-1 , 95% CI 0.09-0.40; P = 0.001). aApoA-I titres at baseline were correlated with decreased PON activity. CONCLUSIONS: The rise in HDL-C achieved with ERN was not matched by improved antioxidant capacity, eventually hampered by the emergence of aApoA-I antibodies. These results may explain why Niacin and other lipid lowering agents fail to reduce cardiovascular risk.info:eu-repo/semantics/publishedVersio

Seed and Seedling Anatomy in Euterpe oleraceae Mart. during the Germination Process

peer reviewe

Antibodies against HDL Components in Ischaemic Stroke and Coronary Artery Disease

Quantitative and qualitative defects of high-density lipoprotein (HDL) are important in atherogenesis. In this study, we investigated whether antibodies against HDL components had additional value to conventional cardiovascular risk factors for the diagnosis of ischaemic stroke (IS) and coronary artery disease (CAD). Cross-sectional study was conducted on 53 patients with IS, 51 with CAD and 55 healthy controls, and in vitro studies to validate findings of the clinical study. We determined serum immunoglobulin G (IgG) antibodies against HDL (aHDL), apolipoproteins (aApoA-I, aApoA-II and aApoC-I) and paraoxonase-1 (aPON1) as well as PON1 activity (PON1a), total antioxidant capacity and biomarkers of endothelial activation (serum nitric oxide metabolites, 3-nitrotyrosine, VCAM-1 and ICAM-1); in vitro assays tested the capacity of IgG aHDL purified from high titer patients to inhibit PON1a and to reverse protective effect of HDL on endothelial cells. IgG aHDL, aApoA-I and aPON1 were higher in IS and CAD than controls (p < 0.001), predicted negatively PON1a and positively VCAM-1 and ICAM-1. By adding IgG aHDL and aApoA-I to a traditional cardiovascular risk factors model for IS and by adding IgG aHDL in a similar model for CAD, we obtained better discrimination of IS and CAD from healthy controls. IgG aHDL purified from IS and CAD inhibited PON1a by 38% (p < 0.01) and abrogated the protective effect of HDL on VCAM-1 expression by 126% compared with non-specific human IgG (p < 0.001). IgG against HDL components interfere with the antioxidant and anti-inflammatory properties of HDL and may represent novel biomarkers for vascular disease that need to be investigated in prospective studies.info:eu-repo/semantics/publishedVersio

SmartEx: a case study on user profiling and adaptation in exhibition booths

An investigation into user profiling and adaptation with exhibition booth as a case study is reported. First a review of the field of exhibitions and trade fairs and a summary introduction to adaptation and profiling are given. We then introduce three criteria for the evaluation of exhibition booth: effectiveness, efficiency and affect. Effectiveness is related the amount of information collected, efficiency is a measurement of the time taken to collect the information, and affect is the perception of the experience and the mood booth visitors have during and after their visit. We have selected these criteria to assess adaptive and profiled exhibition booths, we call smart exhibition (SmartEx). The assessment is performed with an experiment with three test conditions (non-profiled/non adaptive, profiled/non-adaptive and profiled adaptive presentations). Results of the experiment are presented along discussion. While there is significant improvements of effectiveness and efficiency between the two-first test conditions, the improvement is not significant for the last test condition, for reasons explained. As for the affect, the results show that it has an under-estimated importance in people minds and that it should be addressed more carefully

Magnetic Fluffy Dark Matter

We explore extensions of inelastic Dark Matter and Magnetic inelastic Dark Matter where the WIMP can scatter to a tower of heavier states. We assume a WIMP mass $m_\chi \sim \mathcal{O}(1-100)$ GeV and a constant splitting between successive states $\delta \sim\mathcal{O}(1 - 100)$ keV. For the spin-independent scattering scenario we find that the direct experiments CDMS and XENON strongly constrain most of the DAMA/LIBRA preferred parameter space, while for WIMPs that interact with nuclei via their magnetic moment a region of parameter space corresponding to $m_{\chi}\sim 11$ GeV and $\delta < 15$ keV is allowed by all the present direct detection constraints.Comment: 16 pages, 6 figures, added comments about magnetic moment form factor to Sec 3.1.2 and results to Sec 3.2.2, final version to be published in JHE

The Cosmology of Composite Inelastic Dark Matter

Composite dark matter is a natural setting for implementing inelastic dark matter - the O(100 keV) mass splitting arises from spin-spin interactions of constituent fermions. In models where the constituents are charged under an axial U(1) gauge symmetry that also couples to the Standard Model quarks, dark matter scatters inelastically off Standard Model nuclei and can explain the DAMA/LIBRA annual modulation signal. This article describes the early Universe cosmology of a minimal implementation of a composite inelastic dark matter model where the dark matter is a meson composed of a light and a heavy quark. The synthesis of the constituent quarks into dark mesons and baryons results in several qualitatively different configurations of the resulting dark matter hadrons depending on the relative mass scales in the system.Comment: 31 pages, 4 figures; references added, typos correcte

An Electron Fixed Target Experiment to Search for a New Vector Boson A' Decaying to e+e-

We describe an experiment to search for a new vector boson A' with weak coupling alpha' > 6 x 10^{-8} alpha to electrons (alpha=e^2/4pi) in the mass range 65 MeV < m_A' < 550 MeV. New vector bosons with such small couplings arise naturally from a small kinetic mixing of the "dark photon" A' with the photon -- one of the very few ways in which new forces can couple to the Standard Model -- and have received considerable attention as an explanation of various dark matter related anomalies. A' bosons are produced by radiation off an electron beam, and could appear as narrow resonances with small production cross-section in the trident e+e- spectrum. We summarize the experimental approach described in a proposal submitted to Jefferson Laboratory's PAC35, PR-10-009. This experiment, the A' Experiment (APEX), uses the electron beam of the Continuous Electron Beam Accelerator Facility at Jefferson Laboratory (CEBAF) at energies of ~1-4 GeV incident on 0.5-10% radiation length Tungsten wire mesh targets, and measures the resulting e+e- pairs to search for the A' using the High Resolution Spectrometer and the septum magnet in Hall A. With a ~1 month run, APEX will achieve very good sensitivity because the statistics of e+e- pairs will be ~10,000 times larger in the explored mass range than any previous search for the A' boson. These statistics and the excellent mass resolution of the spectrometers allow sensitivity to alpha'/alpha one to three orders of magnitude below current limits, in a region of parameter space of great theoretical and phenomenological interest. Similar experiments could also be performed at other facilities, such as the Mainz Microtron.Comment: 19 pages, 12 figures, 2 table

Low-Energy Signals from Kinetic Mixing with a Warped Abelian Hidden Sector

We investigate the detailed phenomenology of a light Abelian hidden sector in the Randall-Sundrum framework. Relative to other works with light hidden sectors, the main new feature is a tower of hidden Kaluza-Klein vectors that kinetically mix with the Standard Model photon and Z. We investigate the decay properties of the hidden sector fields in some detail, and develop an approach for calculating processes initiated on the ultraviolet brane of a warped space with large injection momentum relative to the infrared scale. Using these results, we determine the detailed bounds on the light warped hidden sector from precision electroweak measurements and low-energy experiments. We find viable regions of parameter space that lead to significant production rates for several of the hidden Kaluza-Klein vectors in meson factories and fixed-target experiments. This offers the possibility of exploring the structure of an extra spacetime dimension with lower-energy probes.Comment: (1+32) Pages, 13 Figures. v2: JHEP version (minor modifications, results unchanged

Diagnosing Spin at the LHC via Vector Boson Fusion

We propose a new technique for determining the spin of new massive particles that might be discovered at the Large Hadron Collider. The method relies on pair-production of the new particles in a kinematic regime where the vector boson fusion production mechanism is enhanced. For this regime, we show that the distribution of the leading jets as a function of their relative azimuthal angle can be used to distinguish spin-0 from spin-1/2 particles. We illustrate this effect by considering the particular cases of (i) strongly-interacting, stable particles and (ii) supersymmetric particles carrying color charge. We argue that this method should be applicable in a wide range of new physics scenarios.Comment: 5 pages, 4 figure