Geo-material provenance and technological properties investigation in Copper Age menhirs production at Allai (central-western Sardinia, Italy)

During the 2nd millennium BC anthropomorphic menhirs belonging to a 3rd millennium BC sanctuary were reused as building material in the Arasseda Nuraghe (Sardinia, Italy). To analyse the Arasseda menhirs and the local Monte Ironi geological samples (presenting similar visual features), chemical (pXRF, ICP-OES, ICP-MS), mineralogical-chemical (PXRD) and physical (Mohs hardness) measurements were performed. Through the experimental data, the menhirs source provenance and the technological properties (workability, durability) of the raw material chosen for sculptural purposes during Copper Age were investigated. To the authors’ knowledge this is the first archaeometric study on the Arasseda menhirs (the third on Sardinian menhirs) and one between the few recently developed on European megaliths

Comparisons of Hyv\"arinen and pairwise estimators in two simple linear time series models

The aim of this paper is to compare numerically the performance of two estimators based on Hyv\"arinen's local homogeneous scoring rule with that of the full and the pairwise maximum likelihood estimators. In particular, two different model settings, for which both full and pairwise maximum likelihood estimators can be obtained, have been considered: the first order autoregressive model (AR(1)) and the moving average model (MA(1)). Simulation studies highlight very different behaviours for the Hyv\"arinen scoring rule estimators relative to the pairwise likelihood estimators in these two settings.Comment: 14 pages, 2 figure

Comparing predictive distributions in EMOS

EMOS models are widely used post-processing techniques for obtaining predictive distributions from ensembles for future weather variables. A predictive distribution can be easily obtained by substituting the unknown parameters with suitable estimates in the distribution of the future variable, thus obtaining a so called estimative distribution. Nonetheless, these distributions may perform poorly in terms of coverage probability of the corresponding quantiles. In this work we propose the use of calibrated predictive distributions in the context of EMOS models. The proposed calibrated predictive distribution improves on estimative solutions, producing quantiles with exact coverage level. A simulation study assesses the goodness of the calibrated predictive distribution in terms of coverage probabilities and also logarithmic score and CRPS

Modern likelihood inference for the parameter of skewness: an application to monozygotic twin studies

We consider the use of modern likelihood asymptotics in the construction of confidence intervals for the parameter which determines the skewness of the distribution of the maximum/minimumof an exchangeable bivariate normal randomvector. This distribution represents the reference model for assessing the degree of concordance of a continuos mono-zygotic twin trait when interest focuses on the pairwise maximum or minimum. Simulation studies were conducted to investigate the accuracy of the proposed method and to compare it to available alternatives. Accuracy is evaluated in terms of both coverage probability and expected length of the interval. We, furthermore, illustrate the suitability of our method by re-analyzing the data from a study which compares different measurements taken on the brains of mono-zygotic twins

Likelihood Asymptotics in Nonregular Settings: A Review with Emphasis on the Likelihood Ratio

This paper reviews the most common situations where one or more regularity conditions which underlie classical likelihood-based parametric inference fail. We identify three main classes of problems: boundary problems, indeterminate parameter problems -- which include non-identifiable parameters and singular information matrices -- and change-point problems. The review focuses on the large-sample properties of the likelihood ratio statistic. We emphasize analytical solutions and acknowledge software implementations where available. We furthermore give summary insight about the possible tools to derivate the key results. Other approaches to hypothesis testing and connections to estimation are listed in the annotated bibliography of the Supplementary Material

Colloidal CoFe2O4-based nanoparticles for Magnetic Fluid Hyperthermia

In the field of biomedicine, important issues to address are the early-stage diagnosis and targeted therapies. Since the last two decades, magnetic nanoparticles have been proposed as potentially powerful due to their unique chemical-physical properties. Magnetic nanoparticles can be applied in a wide variety of biomedical fields from the magnetic separation and Magnetic Resonance Imaging (MRI) to drug delivery and Magnetic Fluid Hyperthermia (MFH).1 In particular, MFH is based on the heat released by magnetic nanoparticles subjected to an alternate external magnetic field. Among the different material features affecting the hyperthermic efficiency, the magnetic properties are clearly the most important. Therefore, the optimisation of the magnetic properties, aimed to increase the heating ability and to reduce the magnetic material dose to be inserted in the human body, is still an active research field. In 2013 alone, 682 works have been published in the literature on the topic of magnetic hyperthermia.2 Despite cobalt toxicity, cobalt-containing materials and especially cobalt ferrite nanoparticles have been proposed as promising heat mediators due to its high anisotropy.3–13 In this thesis, the results obtained on two different systems, designed with the idea of studying the effect on the hyperthermic properties of proper tuning of the magnetic properties, are presented. Both the sets of samples are based on cobalt ferrite nanoparticles. The first strategy consists on the substitution of cobalt ions with zinc ones with the aim of tuning the magnetic properties of the system and, at the same time, decrease the toxicity of the material. The second way is on the contrary represented by the coating of cobalt ferrite cores by means of biocompatible or less toxic isostructural phases (i.e. magnetite/maghemite or manganese ferrite)

Two generalizations of the skew-normal distribution and two variants of McCarthy's theorem

The thesis is structured into two main parts. The first and major part is concerned with the skew-normal distribution, introduced by Azzalini (1985) [6], while the second one is connected with the scoring rules. In part one the problem of finding confidence intervals for the skewness parameter of the skew-normal distribution is addressed. Two new five-parameter continuous distributions which generalize the skew-normal distribution as well as some other well-known distributions are proposed and studied. Some mathematical properties of both distributions are derived. Part two is focused on the extension of the theorem of characterization of scoring rules, due to McCarthy (1956) ([16] of part 2), in two directions: for countable infinite sample spaces, but with bounded score and for finite sample spaces, but with unbounded score