Bayesian approach to LR assessment in case of rare type match: careful derivation and limits

The likelihood ratio (LR) is largely used to evaluate the relative weight of forensic data regarding two hypotheses and for its assessment Bayesian methods are widespread in the forensic field. However, the Bayesian `recipe' for the LR presented in most of literature consists in plugging-in Bayesian estimates of the involved nuisance parameters into a frequentist-defined LR: frequentist and Bayesian methods are thus mixed, giving rise to solutions obtained by hybrid reasoning. This paper provides the derivation of a proper Bayesian approach to assess LR for the `rare type match problem', the situation in which the expert wants to evaluate a match between the profile of a suspect and that of a trace from the crime scene, and this profile has never been observed before in the database of reference. Bayesian LR assessment using the two most popular Bayesian models (beta-binomial and Dirichlet-multinomial) is discussed and compared to corresponding plug-in versions

A nonparametric Bayesian approach to the rare type match problem

The "rare type match problem" is the situation in which the suspect's DNA profile, matching the DNA profile of the crime stain, is not in the database of reference. The evaluation of this match in the light of the two competing hypotheses (the crime stain has been left by the suspect or by another person) is based on the calculation of the likelihood ratio and depends on the population proportions of the DNA profiles, that are unknown. We propose a Bayesian nonparametric method that uses a two-parameter Poisson Dirichlet distribution as a prior over the ranked population proportions, and discards the information about the names of the different DNA profiles. This fits very well the data coming from European Y-STR DNA profiles, and the calculation of the likelihood ratio becomes quite simple thanks to a justified Empirical Bayes approach.Comment: arXiv admin note: text overlap with arXiv:1506.0844

Impact of model choice on LR assessment in case of rare haplotype match (frequentist approach)

The likelihood ratio (LR) measures the relative weight of forensic data regarding two hypotheses. Several levels of uncertainty arise if frequentist methods are chosen for its assessment: the assumed population model only approximates the true one and its parameters are estimated through a database. Moreover, it may be wise to discard part of data, especially that only indirectly related to the hypotheses. Different reductions define different LRs. Therefore, it is more sensible to talk about "a" LR instead of "the" LR, and the error involved in the estimation should be quantified. Two frequentist methods are proposed in the light of these points for the `rare type match problem', that is when a match between the perpetrator's and the suspect's DNA profile, never observed before in the database of reference, is to be evaluated

A first principles based polarizable O(N) interatomic force field for bulk silica

We present a reformulation of the Tangney-Scandolo interatomic force field for silica J. Chem. Phys. 117, 8898 (2002), which removes the requirement to perform an Ewald summation. We use a Yukawa factor to screen electrostatic interactions and a cutoff distance to limit the interatomic potential range to around 10 Å. A reparametrization of the potential is carried out, fitting to data from density functional theory calculations. These calculations were performed within the local density approximation since we find that this choice of functional leads to a better match to the experimental structural and elastic properties of quartz and amorphous silica than the generalized gradient approximation approach used to parametrize the original Tangney-Scandolo force field. The resulting O(N) scheme makes it possible to model hundreds of thousands of atoms with modest computational resources, without compromising the force field accuracy. The new potential is validated by calculating structural, elastic, vibrational, and thermodynamic properties of $\alpha$-quartz and amorphous silica

Modeling the Epidemic Outbreak and Dynamics of COVID-19 in Croatia

The paper deals with a modeling of the ongoing epidemic caused by Coronavirus disease 2019 (COVID-19) on the closed territory of the Republic of Croatia. Using the official public information on the number of confirmed infected, recovered and deceased individuals, the modified SEIR compartmental model is developed to describe the underlying dynamics of the epidemic. Fitted modified SEIR model provides the prediction of the disease progression in the near future, considering strict control interventions by means of social distancing and quarantine for infected and at-risk individuals introduced at the beginning of COVID-19 spread on February, 25th by Croatian Ministry of Health. Assuming the accuracy of provided data and satisfactory representativeness of the model used, the basic reproduction number is derived. Obtained results portray potential positive developments and justify the stringent precautionary measures introduced by the Ministry of Health.Comment: 5 pages, 6 figures, to appear in the Proceedings of the SpliTech2020 conferenc

Considérer sur le plan économique, environnemental, légal, communicationnel et logistique, la possibilité de troquer l’eau en bouteille par de l’eau courante dans le domaine hospitalier tout particulièrement aux Hôpitaux Universitaires de Genève

Le présent travail a pour but d’étudier la faisabilité d’un passage de la consommation de l’eau en bouteille à l’eau du réseau