Finite Sample Performance in CointegrationAnalysis of Nonlinear Time Series with LongMemory

Nonlinear functions of multivariate financial time series can exhibit longmemory and fractional cointegration. However, tools for analysingthese phenomena have principally been justified under assumptionsthat are invalid in this setting. Determination of asymptotic theoryunder more plausible assumptions can be complicated and lengthy.We discuss these issues and present a Monte Carlo study, showingthat asymptotic theory should not necessarily be expected to provide agood approximation to finite-sample behaviour.Fractional cointegration, memory estimation,stochastic volatility.

Fractional Cointegration In StochasticVolatility Models

Asset returns are frequently assumed to be determined by one or more commonfactors. We consider a bivariate factor model, where the unobservable commonfactor and idiosyncratic errors are stationary and serially uncorrelated, but havestrong dependence in higher moments. Stochastic volatility models for the latentvariables are employed, in view of their direct application to asset pricing models.Assuming the underlying persistence is higher in the factor than in the errors, afractional cointegrating relationship can be recovered by suitable transformation ofthe data. We propose a narrow band semiparametric estimate of the factorloadings, which is shown to be consistent with a rate of convergence, and its finitesample properties are investigated in a Monte Carlo experiment.Fractional cointegration, stochastic volatility, narrow band leastsquares, semiparametric analysis.

A BAYESIAN ANALYSIS OF THE AGES OF FOUR OPEN CLUSTERS

In this paper we apply a Bayesian technique to determine the best fit of stellar evolution models to find the main sequence turn off age and other cluster parameters of four intermediate-age open clusters: NGC 2360, NGC 2477, NGC 2660, and NGC 3960. Our algorithm utilizes a Markov chain Monte Carlo technique to fit these various parameters, objectively finding the best fit isochrone for each cluster. The result is a high precision isochrone fit. We compare these results with the those of traditional “by eye” isochrone fitting methods. By applying this Bayesian technique to NGC 2360, NGC 2477, NGC 2660, and NGC 3960 we determine the ages of these clusters to be 1.35 ± 0.05, 1.02 ± 0.02, 1.64 ± 0.04, and 0.860 ± 0.04 Gyr, respectively. The results of this paper continue our effort to determine cluster ages to higher precision than that offered by these traditional methods of isochrone fitting

Is the Lambda CDM Model Consistent with Observations of Large-Scale Structure?

The claim that large-scale structure data independently prefers the Lambda Cold Dark Matter model is a myth. However, an updated compilation of large-scale structure observations cannot rule out Lambda CDM at 95% confidence. We explore the possibility of improving the model by adding Hot Dark Matter but the fit becomes worse; this allows us to set limits on the neutrino mass.Comment: To appear in Proceedings of "Sources and Detection of Dark Matter/Energy in the Universe", ed. D. B. Cline. 6 pages, including 2 color figure

Identifying spatial and temporal dynamics of proglacial groundwater-surface-water exchange using combined temperature-tracing methods

The effect of proglacial groundwater systems on surface hydrology and ecology in cold regions often is neglected when assessing the ecohydrological implications of climate change. We present a novel approach in which we combined 2 temperature-tracing techniques to assess the spatial patterns and short-term temporal dynamics of groundwater–surface-water exchange in the proglacial zone of Skaftafellsjökull, a retreating glacier in southeastern Iceland. Our study focuses on localized groundwater discharge to a surface-water environment, where high temporal- and spatial-resolution mapping of sediment surface and subsurface temperatures (10–15 cm depth) were obtained by Fiber-Optic Distributed Temperature Sensing (FO-DTS). The FO-DTS survey identified temporally consistent locations of temperature anomalies at the sediment–water interface, indicating distinct zones of cooler groundwater upwelling. The high-resolution FO-DTS surveys were combined with calculations of 1-dimensional groundwater seepage fluxes based on 3 vertical sediment temperature profiles, covering depths of 10, 25, and 40 cm below the lake bed. The calculated groundwater seepage rates ranged between 1.02 to 6.10 m/d. We used the combined techniques successfully to identify substantial temporal and spatial heterogeneities in groundwater–surface exchange fluxes that have relevance for the ecohydrological functioning of the investigated system and its potential resilience to environmental change

BAYESIAN ANALYSIS OF TWO STELLAR POPULATIONS IN GALACTIC GLOBULAR CLUSTERS I: STATISTICAL AND COMPUTATIONAL METHODS

We develop a Bayesian model for globular clusters composed of multiple stellar populations, extending earlier statistical models for open clusters composed of simple (single) stellar populations (e.g., van Dyk et al. 2009; Stein et al. 2013). Specifically, we model globular clusters with two populations that differ in helium abundance. Our model assumes a hierarchical structuring of the parameters in which physical properties—age, metallicity, helium abundance, distance, absorption, and initial mass—are common to (i) the cluster as a whole or to (ii) individual populations within a cluster, or are unique to (iii) individual stars. An adaptive Markov chain Monte Carlo (MCMC) algorithm is devised for model fitting that greatly improves convergence relative to its precursor non-adaptive MCMC algorithm. Our model and computational tools are incorporated into an open-source software suite known as BASE-9. We use numerical studies to demonstrate that our method can recover parameters of two-population clusters, and also show model misspecification can potentially be identified. As a proof of concept, we analyze the two stellar populations of globular cluster NGC 5272 using our model and methods. (BASE-9 is available from GitHub: https://github.com/argiopetech/base/releases)

On Automorphisms and Focal Subgroups of Blocks

Given a p-block B of a finite group with defect group P and fusion system on P, we show that the rank of the group is invariant under stable equivalences of Morita type. The main ingredients are the construction, due to Broué and Puig, a theorem of Weiss on linear source modules, arguments of Hertweck and Kimmerle applying Weiss’ theorem to blocks, and connections with integrable derivations in the Hochschild cohomology of block algebras

Divergent mathematical treatments in utility theory

In this paper I study how divergent mathematical treatments affect mathematical modelling, with a special focus on utility theory. In particular I examine recent work on the ranking of information states and the discounting of future utilities, in order to show how, by replacing the standard analytical treatment of the models involved with one based on the framework of Nonstandard Analysis, diametrically opposite results are obtained. In both cases, the choice between the standard and nonstandard treatment amounts to a selection of set-theoretical parameters that cannot be made on purely empirical grounds. The analysis of this phenomenon gives rise to a simple logical account of the relativity of impossibility theorems in economic theory, which concludes the paper

Kinematics of the Local Universe XIII. 21-cm line measurements of 452 galaxies with the Nan\c{c}ay radiotelescope, JHK Tully-Fisher relation and preliminary maps of the peculiar velocity field

This paper presents 452 new 21-cm neutral hydrogen line measurements carried out with the FORT receiver of the meridian transit Nan\c{c}ay radiotelescope (NRT) in the period April 2003 -- March 2005. This observational programme is part of a larger project aiming at collecting an exhaustive and magnitude-complete HI extragalactic catalogue for Tully-Fisher applications (the so-called KLUN project, for Kinematics of the Local Universe studies, end in 2008). The whole on-line HI archive of the NRT contains today reduced HI-profiles for ~4500 spiral galaxies of declination delta > -40° (http://klun.obs-nancay.fr). As an example of application, we use direct Tully-Fisher relation in three (JHK) bands in deriving distances to a large catalog of 3126 spiral galaxies distributed through the whole sky and sampling well the radial velocity range between 0 and 8000 km/s. Thanks to an iterative method accounting for selection bias and smoothing effects, we show as a preliminary output a detailed and original map of the velocity field in the Local Universe

Lupus and Sjögren’s syndrome distinct disease endotypes clustered based on activity scores and immune profiles

Background: Sjögren’s syndrome (SS) is a chronic autoimmune disorder affecting approximately 0.1–0.4% of the general population with a female-to-male ratio of 9:1 usually diagnosed in the fourth and fifth decades of life [1]. Clinically, SS is typified by ocular and oral dryness developed as a consequence of the autoimmune process. It may occur either alone, as primary (p)SS, or secondary to other autoimmune disease, often rheumatoid arthritis (RA), systemic lupus erythematosus (SLE) or systemic sclerosis, secondary (s)SS. Objectives: 1) Identify the peripheral B and T cells abnormalities in patients with pSS, secondary SS associated with systemic lupus erythematosus (SLE) and SLE alone in comparison to healthy donors. 2) Correlate immune phenotypes with clinical features and serological parameters. 3) Identify distinct patients’ endotypes relevant for therapeutic strategies. Methods: Blood samples, clinical and laboratory parameters from 28 patients with pSS, 32 SLE, 15 SS/SLE and age/sex-matched HC were obtained. Immunophenotyping and lipid-raft analyses were performed by flow-cytometry. Results: There were distinct CD19+ B cells, and CD4+ and CD8+ T cell subpopulations observed in pSS, SLE and SS/SLE patients compared to healthy donors. SS/SLE have the most striking B cell phenotype abnormalities than patients with pSS or SLE (increased Bm2 cells and decreased early and late Bm5 cells).There were significant positive and negative correlations of immune cells with clinical parameters in pSS, SLE and SS/SLE patients. The fold-change of memory B cells was significantly reduced in all disease groups with comparison to healthy controls. Fold-change of CD8+ T responder cells were significantly reduced in all diseases, and similarly, CD4+ naïve T cells in SLE and SS/SLE. A highly significant increase in CD4+ T regulatory was observed in pSS. Hierarchical clustering of immune cells in patients yielded 5 distinct endotypes, with clustering reflected in patients with similar disease activity scores. Conclusions: This is the first comprehensive immunophenotype analysis performed patients with pSS, SLE and SS/SLE. We identified significant reduction in memory B cells fold-changed in all disease groups, reduction in CD4+ naïve T cells in SLE and SS/SLE and reduction in T responders in all disease CD8+ in comparison to healthy donors. The most significant T cell abnormalities were found in patients with SLE, however a significant correlation between lipid raft expression as marker of cell activation and disease activity score (ESSDAI) was found only in pSS patients. The five distinct disease endotype clustering showed distinct immune profile in patients with overlapping autoimmune conditions which is particularly relevant for stratification of therapy