Evolution of fermionic systems as an expectation over Poisson processes

We derive an exact probabilistic representation for the evolution of a Hubbard model with site- and spin-dependent hopping coefficients and site-dependent interactions in terms of an associated stochastic dynamics of a collection of Poisson processes.Comment: 4 pages, contribution to the proceedings of tenth International Conference on Recent Progress in Many-Body Theories, Seattle, 199

External validity of randomized controlled trials on Alzheimer's disease: the biases of frailty and biological aging

To date, the external validity of randomized controlled trials (RCTs) on Alzheimer's disease (AD) has been assessed only considering monodimensional variables. Nevertheless, looking at isolated and single characteristics cannot guarantee a sufficient level of appreciation of the AD patients' complexity. The only way to understand whether the two worlds (i.e., research and clinics) deal with the same type of patients is to adopt multidimensional approaches more holistically reflecting the biological age of the individual. In the present study, we compared measures of frailty/biological aging [assessed by a Frailty Index (FI)] of a sample of patients with AD resulted eligible and subsequently included in phase III RCTs compared to patients referring to the same clinical service, but not considered for inclusion. The "RCT sample" and the "real world sample" were found to be statistically similar for all the considered sociodemographic and clinical variables. Nevertheless, the "real world sample" was found to be significantly frailer compared to the "RCT sample," as indicated by higher FI scores [0.28 (SD 0.1) vs. 0.17 (SD 0.1);p < 0.001, respectively]. Moreover, when assessing the relationship between FI and age, we found that the correlation was almost null in the "RCT sample" (Spearman'sr = 0.01;p = 0.98), while it was statistically significant in the "real world sample" (r = 0.49;p = 0.02). The application of too rigid designs may result in the poor representativeness of RCT samples. It may even imply the study of a condition biologically different from that observed in the "real world." The adoption of multidimensional measures capable to capture the individual's biological age may facilitate evaluating the external validity of clinical studies, implicitly improving the interpretation of the results and their translation in the clinical arena

Wasserstein stability of porous medium-type equations on manifolds with Ricci curvature bounded below

Given a complete, connected Riemannian manifold $\mathbb{M}^n$ with Ricci curvature bounded from below, we discuss the stability of the solutions of a porous medium-type equation with respect to the 2-Wasserstein distance. We produce (sharp) stability estimates under negative curvature bounds, which to some extent generalize well-known results by Sturm and Otto-Westdickenberg. The strategy of the proof mainly relies on a quantitative $L^1-L^\infty$ smoothing property of the equation considered, combined with the Hamiltonian approach developed by Ambrosio, Mondino and Savar\'e in a metric-measure setting

Comparing indirect encodings by evolutionary attractor analysis in the trait space of modular robots

In evolutionary robotics, the representation of the robot is of primary importance. Often indirect encodings are used, whereby a complex developmental process grows a body and a brain from a genotype. In this work, we aim at improving the interpretability of robot morphologies and behaviours resulting from indirect encoding. We develop and use a methodology that focuses on the analysis of evolutionary attractors, represented in what we call the trait space: Using trait descriptors defined in the literature, we define morphological and behavioural Cartesian planes where we project the phenotype of the final population. In our experiments we show that, using this analysis method, we are able to better discern the effect of encodings that differ only in minor details

The effect of severity and personality on the psychotic presentation of major depression

The aim of the present study was to evaluate whether symptom severity or personality traits are associated with psychotic symptoms in major depression (MD), since it is still debated whether psychotic depression represents the most severe form of depression or the effect of personality structure. The study included 163 patients affected by MD who were divided into four groups on the basis of the presence/absence of melancholic features and psychotic symptoms. All subjects completed the Structured Clinical Interview for DSM-IV Disorders (SCID-IV), the Structured Clinical Interview for DSM-IV Personality Disorders (SIDP-IV) and the Hamilton Rating Scale for Depression (Ham-D). Personality was assessed after MD remission (absence of DSM-IV criteria and Ham-D score lower than 7 for at least 2 months). Psychotic symptoms were positively associated with symptom severity (higher Ham-D total score) and with paranoid and schizotypal traits and negatively related to histrionic traits. Our data support the view that the effect of paranoid-schizotypal traits and symptom severity on the presence of psychotic symptoms in MD occurs separately and they are independent of each other. © 2011 Elsevier Ltd

The TAS-20 more likely measures negative affects rather than alexithymia itself in patients with major depression, panic disorder, eating disorders and substance use disorders

Background This study evaluates whether the difference in Toronto Alexithymia Scale-20 item (TAS-20) between patients with major depression (MD), panic disorder (PD), eating disorders (ED), and substance use disorders (SUD) and healthy controls persisted after controlling for the severity of anxiety and depression. Methods Thirty-eight patients with MD, 58 with PD, 52 with ED, and 30 with SUD and 78 healthy controls (C) completed the TAS-20, the Hamilton Rating Scale for Anxiety (Ham-A), the Hamilton Rating Scale for Depression (Ham-D). Results The differences in TAS-20 scores observed between patient groups, regardless of the type of their disorders, and controls disappeared after controlling for the effect of anxiety and depression severity. In contrast, the differences in severity of anxiety and depression between patients and controls were still present, after excluding the effect of alexithymic levels. Conclusions Our data suggest that alexithymic levels, as measured by the TAS-20, are modulated by the severity of symptoms, supporting the view that alexithymia can represent a state phenomenon in patients with MD, PD, ED and SUD, because the TAS-20 seems overly sensitive to a general distress syndrome, and it is more likely to measure negative affects rather than alexithymia itself. \ua9 2014 Elsevier Inc

Hallermann–Streiff syndrome with severe bilateral enophthalmos and radiological evidence of silent brain syndrome: a new congenital silent brain syndrome?

BACKGROUND: We present the first case of a congenital form of silent brain syndrome (SBS) in a young patient affected by Hallermann-Streiff syndrome (HSS) and the surgical management of the associated eyelid anomalies. METHODS: HSS signs were evaluated according to the Francois criteria. Orbital computed tomography (CT) and genetic analysis were performed. An upper eyelid retractor-free recession was performed. Follow-up visits were performed at day 1, weeks 1 and 3, and months 3, 6, 9 (for both eyes), and 12 (for left eye) after surgery. RESULTS: The patient exhibited six of the seven signs of HSS. Orbital CT showed bilateral enophthalmos and upward bowing of the orbital roof with air entrapment under the upper eyelid as previously described for SBS. Genetic analysis showed a 2q polymorphism. During follow-up, the cornea showed absence of epithelial damage and the upper eyelids were lowered symmetrically, with a regular contour. CONCLUSION: Our HSS patient shares features with SBS. We postulate that SBS could include more than one pattern, ie, an acquired form following ventriculoperitoneal shunting and this newly reported congenital form in our HSS patient in whom typical syndromic skull anomalies led to this condition. The surgical treatment has been effective in restoring an appropriate lid level, with good globe apposition and a good cosmetic result

Improving RL Power for On-Line Evolution of Gaits in Modular Robots

This paper addresses the problem of on-line gait learning in modular robots whose shape is not known in advance. The best algorithm for this problem known to us is a reinforcement learning method, called RL PoWER. In this study we revisit the original RL PoWER algorithm and observe that in essence it is a specific evolutionary algorithm. Based on this insight we propose two modifications of the main search operators and compare the quality of the evolved gaits when either or both of these modified operators are employed. The results show that using 2-parent crossover as well as mutation with self- adaptive step-sizes can significantly improve the performance of the original algorithm