Equilibrium and non-equilibrium Ising models by means of PCA

We propose a unified approach to reversible and irreversible PCA dynamics, and we show that in the case of 1D and 2D nearest neighbour Ising systems with periodic boundary conditions we are able to compute the stationary measure of the dynamics also when the latter is irreversible. We also show how, according to [DPSS12], the stationary measure is very close to the Gibbs for a suitable choice of the parameters of the PCA dynamics, both in the reversible and in the irreversible cases. We discuss some numerical aspects regarding this topic, including a possible parallel implementation

On the blockage problem and the non-analyticity of the current for the parallel TASEP on a ring

The Totally Asymmetric Simple Exclusion Process (TASEP) is an important example of a particle system driven by an irreversible Markov chain. In this paper we give a simple yet rigorous derivation of the chain stationary measure in the case of parallel updating rule. In this parallel framework we then consider the blockage problem (aka slow bond problem). We find the exact expression of the current for an arbitrary blockage intensity $\varepsilon$ in the case of the so-called rule-184 cellular automaton, i.e. a parallel TASEP where at each step all particles free-to-move are actually moved. Finally, we investigate through numerical experiments the conjecture that for parallel updates other than rule-184 the current may be non-analytic in the blockage intensity around the value $\varepsilon = 0$

On the statistical description of the inbound air traffic over Heathrow airport

We present a model to describe the inbound air traffic over a congested hub. We show that this model gives a very accurate description of the traffic by the comparison of our theoretical distribution of the queue with the actual distribution observed over Heathrow airport. We discuss also the robustness of our model

Predictive modeling of inbound demand at major European airports with Poisson and Pre-Scheduled Random Arrivals

This paper presents an exhaustive study of the arrivals process at eight major European airports. Using inbound traffic data, we define, compare, and contrast a data-driven in-homogeneous Poisson and Pre-Scheduled Random Arrivals (PSRA) point process with respect to their ability to predict future demand. As part of this analysis, we show the weaknesses and difficulties of using a non-homogeneous Poisson process to model the arrivals stream. On the other hand, our novel and simple data-driven (PSRA) model captures and predicts the main properties of the typical arrivals stream with good accuracy. These results have important implication for the modeling and simulation-based analyses of inbound traffic and can improve the use of available capacity, thus reducing air traffic delays. In a nutshell, the results lead to the conclusion that, in the European context, the (PSRA) model provides more accurate predictions

Marginal structural models with dose-delay joint-exposure for assessing variations to chemotherapy intensity

Marginal structural models are causal models designed to adjust for time-dependent confounders in observational studies with dynamically adjusted treatments. They are robust tools to assess causality in complex longitudinal data. In this paper, a marginal structural model is proposed with an innovative dose-delay joint-exposure model for Inverse-Probability-of-Treatment Weighted estimation of the causal effect of alterations to the therapy intensity. The model is motivated by a precise clinical question concerning the possibility of reducing dosages in a regimen. It is applied to data from a randomised trial of chemotherapy in osteosarcoma, an aggressive primary bone-tumour. Chemotherapy data are complex because their longitudinal nature encompasses many clinical details like composition and organisation of multi-drug regimens, or dynamical therapy adjustments. This manuscript focuses on the clinical dynamical process of adjusting the therapy according to the patient’s toxicity history, and the causal effect on the outcome of interest of such therapy modifications. Depending on patients’ toxicity levels, variations to therapy intensity may be achieved by physicians through the allocation of either a reduction or a delay of the next planned dose. Thus, a negative feedback is present between exposure to cytotoxic agents and toxicity levels, which acts as time-dependent confounders. The construction of the model is illustrated highlighting the high complexity and entanglement of chemotherapy data. Built to address dosage reductions, the model also shows that delays in therapy administration should be avoided. The last aspect makes sense from the cytological point of view, but it is seldom addressed in the literature

The concept of care complexity: a qualitative study

Background: Hospital organisations based on the level of care intensity have clearly revealed a concept, that of care complexity, which has been widely used for decades in the healthcare field. Despite its wide use, this concept is still poorly defined and it is often confused with and replaced by similar concepts such as care intensity or workload. This study aims to describe the meaning of care complexity as perceived by nurses in their day-to-day experience of hospital clinical care, rehabilitation, home care, and organisation. Design and methods: Fifteen interviews were conducted with nurses belonging to clinical-care areas and to heterogeneous organisational areas. The interview was of an unstructured type. The participants were selected using a propositional methodology. Colaizzi’s descriptive phenomenological method was chosen for the analysis of the interviews. Results: The nurses who were interviewed predominantly perceive the definition of care complexity as coinciding with that of workload. Nevertheless, the managerial perspective does not appear to be exclusive, as from the in-depth interviews three fundamental themes emerge that are associated with the concept of care complexity: the patient, the nurse and the organisation. Conclusions: The study highlights that care complexity consists of both quantitative and qualitative aspects that do not refer only to the organisational dimension. The use of the terminology employed today should be reconsidered: it appears to be inappropriate to talk of measurement of care complexity, as this concept also consists of qualitative – thus not entirely quantifiable – aspects referring to the person being cared for. In this sense, reference should instead be made to the evaluation of care complexity, which would also constitute a better and more complete basis for defining the nursing skills required in professional nursing practice

Data analytics for trajectory selection and preference-model extrapolation in the European airspace

Representing airspace users’ preferences in Air Traffic Flow Management (ATFM) mathematical models is becoming of high relevance. ATFM models aim to reduce congestion (en-route and at both departure and destination airports) and maximize the Air Traffic Management (ATM) system efficiency by determining the best trajectory for each aircraft. In this framework, the a-priori selection of possible alternative trajectories for each flight plays a crucial role. In this work, we analyze initial trajectories queried from Eurocontrol DDR2 data source. Clustering trajectories yields groups that are homogeneous with respect to known (geometry of the trajectory, speed) and partially known or unknown factors (en-route charges, fuel consumption, weather, etc.). Associations between grouped trajectories and potential choice-determinants are successively explored and evaluated, and the predictive value of the determinants is finally validated. For a given origin-destination pair, this ultimately leads to determining a set of flight trajectories and information on related airspace users’ preferences

Research progress on aerobiology in the last 30 years. A focus on methodology and occupational health

Aerobiology, as a scientific discipline, developed during the last century and has been applied to different types of organisms and scenarios. In the context of the Integrated Evaluation of Indoor Particulate Exposure (VIEPI) project, we conducted a bibliometric study of the scientific literature on aerobiology from the last three decades, establishing the recent advances and the critical issues regarding the application of aerobiological methods to occupational settings. The data were collected from Scopus,Web of Science and PubMed. We explored the distribution of the articles in different years and research areas and realized a bibliometric analysis using the CiteSpace software. The results indicated that the number of publications is increasing. The studies related to environmental sciences were the most represented, while the number of occupational studies was more limited. The most common keywords were related to pollen, fungal spores and their relation with phenology, climate change and human health. This article shows that aerobiology is not restricted to the study of pollen and spores, extending the discipline and the application of aerobiological methods to occupational settings, currently under-explored