HOPF BIFURCATION ANALYSIS FOR SIMPLE THIRD-ORDER QUADRATIC SYSTEMS

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Reconstructing the Density of States by History-Dependent Metadynamics

We present a novel method for the calculation of the energy density of states D(E) for systems described by classical statistical mechanics. The method builds on an extension of a recently proposed strategy that allows the free energy profile of a canonical system to be recovered within a pre-assigned accuracy,[A. Laio and M. Parrinello, PNAS 2002]. The method allows a good control over the error on the recovered system entropy. This fact is exploited to obtain D(E) more efficiently by combining measurements at different temperatures. The accuracy and efficiency of the method are tested for the two-dimensional Ising model (up to size 50x50) by comparison with both exact results and previous studies. This method is a general one and should be applicable to more realistic model systems

Are Major a Posteriori Dietary Patterns Reproducible in the Italian Population? A Systematic Review and Quantitative Assessment

Although a posteriori dietary patterns (DPs) naturally reflect actual dietary behavior in a population, their specificity limits generalizability. Among other issues, the absence of a standardized approach to analysis have further hindered discovery of genuinely reproducible DPs across studies from the same/similar populations. A systematic review on a posteriori DPs from principal component analysis or exploratory factor analysis (EFA) across study populations from Italy provides the basis to explore assessment and drivers of DP reproducibility in a case study of epidemiological interest. First to our knowledge, we carried out a qualitative (i.e., similarity plots built on text descriptions) and quantitative (i.e., congruence coefficients, CCs) assessment of DP reproducibility. The 52 selected articles were published in 2001–2022 and represented dietary habits in 1965–2022 from 70% of the Italian regions; children/adolescents, pregnancy/breastfeeding women, and elderly were considered in 15 articles. The included studies mainly derived EFA-based DPs on food groups from food frequency questionnaires and were of “good quality” according to standard scales. Based on text descriptions, the 186 identified DPs were collapsed into 113 (69 food-based and 44 nutrient-based) apparently different DPs (39.3% reduction), later summarized along with the 3 “Mmixed-Salad/Vegetable-based Patterns,” “Pasta-and-Meat-oriented/Starchy Patterns,” and “Ddairy Products” and “Ssweets/Animal-based Patterns” groups, by matching similar food-based and nutrient-based groups of collapsed DPs. Based on CCs (215 CCs, 68 DPs, 18 articles using the same input lists), all pairs of DPs showing the same/similar names were at least “fairly similar” and ∼81% were “equivalent.” The 30 “equivalent” DPs ended up into 6 genuinely different DPs (80% reduction) that targeted fruits and (raw) vegetables, pasta and meat combined, and cheese and deli meats. Such reduction reflects the same study design, list of input variables, and DP identification method followed across articles from the same groups. This review was registered at PROSPERO as CRD42022341037

Growing spinach in a floating system with different volumes of aerated or non-aerated nutrient solution

Vegetables grown in a floating system may encounter problems of hypoxia at root level, especially in the summer when temperature is high. Depending on the species, oxygen deficiency may cause a lower yield due to a reduction in water and mineral uptake by the plants. On the other hand, plants under oxygen stress may reduce nitrate accumulation, thus ameliorating produce quality. In the present work spinach was grown in summer and autumn in a floating system in different volumes (252, 126 and 60 l per m2 of cultivated area) of aerated or non aerated nutrient solution. Aeration kept oxygen concentration at 7-8 mg l-1 while in the non aerated solution oxygen decreased gradually reaching at harvest, on average, values of 1.92 mg l-1 and 2.83 mg l 1 in summer and autumn respectively. Such levels of hypoxia did not affect yield and did not reduce nitrate accumulation either. On the contrary, in the summer cycle leaf nitrate content was significantly lower when the nutrient solution was aerated. Reduction of the volume of the solution to 60 l m-2 of cultivated area induced a decrease in nitrate accumulation without negative effect on yield. No significant aeration x volume interaction was observed

RNA denaturation: excluded volume, pseudoknots and transition scenarios

A lattice model of RNA denaturation which fully accounts for the excluded volume effects among nucleotides is proposed. A numerical study shows that interactions forming pseudoknots must be included in order to get a sharp continuous transition. Otherwise a smooth crossover occurs from the swollen linear polymer behavior to highly ramified, almost compact conformations with secondary structures. In the latter scenario, which is appropriate when these structures are much more stable than pseudoknot links, probability distributions for the lengths of both loops and main branches obey scaling with nonclassical exponents.Comment: 4 pages 3 figure

Defects-related early childhood caries as hints of possible maternal–fetal health issues: Evidence from medieval northern Italy

Developmental defects of enamel (DDE) are important markers of stress as they arise from the disruption of ameloblastic activity during enamel matrix secretion and mineralization. Defects on the crowns of the deciduous dentition provide insights into maternal–fetal health because they can emerge during intrauterine development as a result of gestational issues. The presence of previous defective enamel represents one of the most predisposing causes of caries development. Thus, circular caries on the deciduous dentition are considered an indicator of stress because of their ascertained relation with dental enamel defects. In bioarchaeological analysis, these lesions allow us to deepen the question of maternal–fetal health issues in the ancient period. Here, we present evidence of defects-related early childhood caries in three infants from a medieval cemetery in northern Italy. The findings in the dentitions of the three subjects were investigated with a multi-analytical approach, including macroscopic examination, microscopic observation, cone-beam computed tomography (CBCT), scanning electron microscopy (SEM), and histological sections. In the specimens analyzed, the lesions observed in the dentitions appeared to have arisen during the fetal period and then protracted in the postnatal life, suggesting the implication of in utero environment and maternal health in the etiology of defects