554 research outputs found
The Partition Function of Multicomponent Log-Gases
We give an expression for the partition function of a one-dimensional log-gas
comprised of particles of (possibly) different integer charge at inverse
temperature {\beta} = 1 (restricted to the line in the presence of a
neutralizing field) in terms of the Berezin integral of an associated non-
homogeneous alternating tensor. This is the analog of the de Bruijn integral
identities [3] (for {\beta} = 1 and {\beta} = 4) ensembles extended to
multicomponent ensembles.Comment: 14 page
Chiral primary one-point functions in the D3-D7 defect conformal field theory
JHEP is an open-access journal funded by SCOAP3 and licensed under CC BY 4.0archiveprefix: arXiv primaryclass: hep-th reportnumber: NORDITA-2012-81 slaccitation: %%CITATION = ARXIV:1210.7015;%%archiveprefix: arXiv primaryclass: hep-th reportnumber: NORDITA-2012-81 slaccitation: %%CITATION = ARXIV:1210.7015;%%C.F.K. and D.Y. were supported in part by FNU through grant number 272-08-0329.
G.W.S. is supported by NSERC of Canada and by the Villum foundation through their
Velux Visiting Professor program
New results for the SQCD Hilbert series
We derive new explicit results for the Hilbert series of N=1 supersymmetric
QCD with U(N_c) and SU(N_c) color symmetry. We use two methods which have
previously been applied to similar computational problems in the analysis of
decay of unstable D-branes: expansions using Schur polynomials, and the log-gas
approach related to random matrix theory.Comment: 33 pages, 2 figures; v2: references and comments on the 3rd order
phase transition added; v3: refs. correcte
Holographic zero sound at finite temperature in the Sakai-Sugimoto model
In this paper, we study the fate of the holographic zero sound mode at finite
temperature and non-zero baryon density in the deconfined phase of the
Sakai-Sugimoto model of holographic QCD. We establish the existence of such a
mode for a wide range of temperatures and investigate the dispersion relation,
quasi-normal modes, and spectral functions of the collective excitations in
four different regimes, namely, the collisionless quantum, collisionless
thermal, and two distinct hydrodynamic regimes. For sufficiently high
temperatures, the zero sound completely disappears, and the low energy physics
is dominated by an emergent diffusive mode. We compare our findings to
Landau-Fermi liquid theory and to other holographic models.Comment: 1+24 pages, 19 figures, PDFTeX, v2: some comments and references
added, v3: some clarifications relating to the different regimes added,
matches version accepted for publication in JHEP, v4: corrected typo in eq.
(3.18
Risk-based early prevention in comparison with routine prevention of dental caries: a 7-year follow-up of a controlled clinical trial; clinical and economic aspects
BACKGROUND: The results in an earlier study with 2–5-year-old children indicated that, in comparison with conventional prevention, a risk-based prevention programme was effective in reducing dental caries in a low-caries community. The aim of the present study was to examine the clinical and economic findings seven years after the cessation of the targeted programme, from the perspective of public health care. METHODS: The present material was collected from the dental records of the public health care centres, and included all dental visits after the 5-year examination until the 12-year examination. The groups were compared in relation to clinically detected caries at the age of 12 years, the number of dental visits needed from 5 to 12 years of age, and the estimation of running costs during these years. Statistical analyses included univariate analysis of variance, and calculation of absolute risk reduction and number needed to treat (NNT) values. RESULTS: At the age of 12 years, DMF was significantly related to the risk category determined ten years earlier, in both study groups. In the risk-based group, the absolute risk reduction for caries in permanent dentition was 0.13 (95% confidence interval 0.06 – 0.21), and the associated NNT value was 8 (95% confidence interval 5 – 17). The total number of preventive, as well as restorative visits was lower in the risk-based than in the routine prevention group. The findings indicate that early risk-based prevention can be correctly targeted, clinically effective, and economically profitable also from the long-term point of view. CONCLUSION: Early prevention of dental caries also has long-term benefits in a 7-year follow-up perspective. This seems to hold true as regards targeting, as well as clinical and economic effectiveness. Success in risk-based prevention enables successful work division, and consequently, economic effectiveness
Holographic DC conductivities from the open string metric
We study the DC conductivities of various holographic models using the open
string metric (OSM), which is an effective metric geometrizing density and
electromagnetic field effect. We propose a new way to compute the nonlinear
conductivity using OSM. As far as the final conductivity formula is concerned,
it is equivalent to the Karch-O'Bannon's real-action method. However, it yields
a geometrical insight and technical simplifications. Especially, a real-action
condition is interpreted as a regular geometry condition of OSM. As
applications of the OSM method, we study several holographic models on the
quantum Hall effect and strange metal. By comparing a Lifshitz background and
the Light-Cone AdS, we show how an extra parameter can change the temperature
scaling behavior of conductivity. Finally we discuss how OSM can be used to
study other transport coefficients, such as diffusion constant, and effective
temperature induced by the effective world volume horizon.Comment: 33 page
Submillimetric GPS distance measurement over short baselines: noise mitigation by global robust estimation
The potential use of GPS technology for precise length determination is currently a topic of
extensive research. A prior work was dedicated to submillimetric length determination over
short baselines and under ideal conditions of data availability and a clear environment. This
paper presents a new computation method suited to the less favourable working conditions that
are usually encountered in practice. It is based on both robust estimation theory and the use
of an ambiguity-free estimation method. As the experimental comparisons with the standard
procedure based on least-squares ambiguity determination show, it provides more stable
values and permits results to be obtained significant to the submillimetre level with time spans
of a few hours.This research is funded by the Spanish Ministry of Science and Innovation (AYA2011-23232).Baselga Moreno, S.; GarcĂa-Asenjo Villamayor, L.; Garrigues Talens, P. (2014). Submillimetric GPS distance measurement over short baselines: noise mitigation by global robust estimation. Measurement Science and Technology. 25(10):1-6. https://doi.org/10.1088/0957-0233/25/10/105004S162510Altamimi, Z., Collilieux, X., & MĂ©tivier, L. (2011). ITRF2008: an improved solution of the international terrestrial reference frame. Journal of Geodesy, 85(8), 457-473. doi:10.1007/s00190-011-0444-4Amiri-Simkooei, A. R., & Tiberius, C. C. J. M. (2006). Assessing receiver noise using GPS short baseline time series. GPS Solutions, 11(1), 21-35. doi:10.1007/s10291-006-0026-8Baire, Q., Bruyninx, C., Legrand, J., Pottiaux, E., Aerts, W., Defraigne, P., … Chevalier, J. M. (2013). Influence of different GPS receiver antenna calibration models on geodetic positioning. GPS Solutions, 18(4), 529-539. doi:10.1007/s10291-013-0349-1Baselga, S. (2007). Global Optimization Solution of Robust Estimation. Journal of Surveying Engineering, 133(3), 123-128. doi:10.1061/(asce)0733-9453(2007)133:3(123)Baselga, S. (2010). Global optimization applied to GPS positioning by ambiguity functions. Measurement Science and Technology, 21(12), 125102. doi:10.1088/0957-0233/21/12/125102Baselga, S. (2014). Ambiguity-Free Method for Fast and Precise GNSS Differential Positioning. Journal of Surveying Engineering, 140(1), 22-27. doi:10.1061/(asce)su.1943-5428.0000111Baselga, S., & GarcĂa-Asenjo, L. (2008). GNSS Differential Positioning by Robust Estimation. Journal of Surveying Engineering, 134(1), 21-25. doi:10.1061/(asce)0733-9453(2008)134:1(21)Baselga, S., & GarcĂa-Asenjo, L. (2008). Multipath Mitigation by Global Robust Estimation. Journal of Navigation, 61(3), 385-392. doi:10.1017/s0373463308004803Baselga, S., GarcĂa-Asenjo, L., & Garrigues, P. (2013). Submillimetric GPS distance measurement over short baselines: case study in inner consistency. Measurement Science and Technology, 24(7), 075001. doi:10.1088/0957-0233/24/7/075001Dow, J. M., Neilan, R. E., & Rizos, C. (2009). The International GNSS Service in a changing landscape of Global Navigation Satellite Systems. Journal of Geodesy, 83(3-4), 191-198. doi:10.1007/s00190-008-0300-3Griffiths, J., & Ray, J. R. (2012). Sub-daily alias and draconitic errors in the IGS orbits. GPS Solutions, 17(3), 413-422. doi:10.1007/s10291-012-0289-1Huber, P. J. (1981). Robust Statistics. Wiley Series in Probability and Statistics. doi:10.1002/0471725250Koivula, H., Häkli, P., Jokela, J., Buga, A., & Putrimas, R. (2011). GPS Metrology: Bringing Traceable Scale to a Local Crustal Deformation GPS Network. International Association of Geodesy Symposia, 105-112. doi:10.1007/978-3-642-20338-1_13Niu, X., Chen, Q., Zhang, Q., Zhang, H., Niu, J., Chen, K., … Liu, J. (2013). Using Allan variance to analyze the error characteristics of GNSS positioning. GPS Solutions, 18(2), 231-242. doi:10.1007/s10291-013-0324-xRay, J., Altamimi, Z., Collilieux, X., & van Dam, T. (2007). Anomalous harmonics in the spectra of GPS position estimates. GPS Solutions, 12(1), 55-64. doi:10.1007/s10291-007-0067-7Snay, R. A., & Soler, T. (2008). Continuously Operating Reference Station (CORS): History, Applications, and Future Enhancements. Journal of Surveying Engineering, 134(4), 95-104. doi:10.1061/(asce)0733-9453(2008)134:4(95)Wieser, A., & Brunner, F. K. (2002). Short Static GPS Sessions: Robust Estimation Results. GPS Solutions, 5(3), 70-79. doi:10.1007/pl00012901Yang, Y. (1999). Robust estimation of geodetic datum transformation. Journal of Geodesy, 73(5), 268-274. doi:10.1007/s001900050243Yang, Y., Song, L., & Xu, T. (2002). Robust estimator for correlated observations based on bifactor equivalent weights. Journal of Geodesy, 76(6-7), 353-358. doi:10.1007/s00190-002-0256-
A holographic model for the fractional quantum Hall effect
Experimental data for fractional quantum Hall systems can to a large extent
be explained by assuming the existence of a modular symmetry group commuting
with the renormalization group flow and hence mapping different phases of
two-dimensional electron gases into each other. Based on this insight, we
construct a phenomenological holographic model which captures many features of
the fractional quantum Hall effect. Using an SL(2,Z)-invariant
Einstein-Maxwell-axio-dilaton theory capturing the important modular
transformation properties of quantum Hall physics, we find dyonic diatonic
black hole solutions which are gapped and have a Hall conductivity equal to the
filling fraction, as expected for quantum Hall states. We also provide several
technical results on the general behavior of the gauge field fluctuations
around these dyonic dilatonic black hole solutions: We specify a sufficient
criterion for IR normalizability of the fluctuations, demonstrate the
preservation of the gap under the SL(2,Z) action, and prove that the
singularity of the fluctuation problem in the presence of a magnetic field is
an accessory singularity. We finish with a preliminary investigation of the
possible IR scaling solutions of our model and some speculations on how they
could be important for the observed universality of quantum Hall transitions.Comment: 86 pages, 16 figures; v.2 references added, typos fixed, improved
discussion of ref. [39]; v.3 more references added and typos fixed, several
statements clarified, v.4 version accepted for publication in JHE
Disk Partition Function and Oscillatory Rolling Tachyons
An exact cubic open string field theory rolling tachyon solution was recently
found by Kiermaier et. al. and Schnabl. This oscillatory solution has been
argued to be related by a field redefinition to the simple exponential rolling
tachyon deformation of boundary conformal theory. In the latter approach, the
disk partition function takes a simple form. Out of curiosity, we compute the
disk partition function for an oscillatory tachyon profile, and find that the
result is nevertheless almost the same.Comment: 17 pages, 2 figures. v4: discussion clarified, appendix added,
conclusions unchanged; version to appear in J.Phys.
Body-mass index and risk of obesity-related complex multimorbidity : an observational multicohort study
Background The accumulation of disparate diseases in complex multimorbidity makes prevention difficult if each disease is targeted separately. We aimed to examine obesity as a shared risk factor for common diseases, determine associations between obesity-related diseases, and examine the role of obesity in the development of complex multimorbidity (four or more comorbid diseases). Methods We did an observational study and used pooled prospective data from two Finnish cohort studies (the Health and Social Support Study and the Finnish Public Sector Study) comprising 114 657 adults aged 16-78 years at study entry (1998-2013). A cohort of 499 357 adults (aged 38-73 years at study entry; 2006-10) from the UK Biobank provided replication in an independent population. BMI and clinical characteristics were assessed at baseline. BMIs were categorised as obesity (Peer reviewe
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