Interparticle gap distributions on one-dimensional lattices

We analyse the successive binding of two species of particles on a one-dimensional discrete lattice, where the second variety is deposited only after complete adsorption of the first. We consider the two extreme cases of a perfectly irreversible initial deposition, with non-sliding particles, and that of a fully equilibrated one. For the latter we construct the exact gap distribution from the Tonks gas partition function. This distribution is contrasted with that obtained from the random sequential adsorption process. We discuss implications for the kinetics of adsorption of the second species, as well as experimental relevance of our results

Diversità culturale, cittadinanza, diritti dei migranti

SOMMARIO: 1. Premessa. – 2. La tutela della diversità culturale nell'ordinamento europeo. – 3. Cittadinanza, appartenenze, diritti dei migranti. – 4. Diritti culturali e cittadinanza europea

The Effects of Statistical Multiplicity of Infection on Virus Quantification and Infectivity Assays

Many biological assays are employed in virology to quantify parameters of interest. Two such classes of assays, virus quantification assays (VQA) and infectivity assays (IA), aim to estimate the number of viruses present in a solution, and the ability of a viral strain to successfully infect a host cell, respectively. VQAs operate at extremely dilute concentrations and results can be subject to stochastic variability in virus-cell interactions. At the other extreme, high viral particle concentrations are used in IAs, resulting in large numbers of viruses infecting each cell, enough for measurable change in total transcription activity. Furthermore, host cells can be infected at any concentration regime by multiple particles, resulting in a statistical multiplicity of infection (SMOI) and yielding potentially significant variability in the assay signal and parameter estimates. We develop probabilistic models for SMOI at low and high viral particle concentration limits and apply them to the plaque (VQA), endpoint dilution (VQA), and luciferase reporter (IA) assays. A web-based tool implementing our models and analysis is also developed and presented. We test our proposed new methods for inferring experimental parameters from data using numerical simulations and show improvement on existing procedures in all limits.Comment: 19 pages, 11 figures, 1 tabl

Onset, timing, and exposure therapy of stress disorders: mechanistic insight from a mathematical model of oscillating neuroendocrine dynamics

The hypothalamic-pituitary-adrenal (HPA) axis is a neuroendocrine system that regulates numerous physiological processes. Disruptions in the activity of the HPA axis are correlated with many stress-related diseases such as post-traumatic stress disorder (PTSD) and major depressive disorder. In this paper, we characterize "normal" and "diseased" states of the HPA axis as basins of attraction of a dynamical system describing the inhibition of peptide hormones such as corticotropin-releasing hormone (CRH) and adrenocorticotropic hormone (ACTH) by circulating glucocorticoids such as cortisol (CORT). In addition to including key physiological features such as ultradian oscillations in cortisol levels and self-upregulation of CRH neuron activity, our model distinguishes the relatively slow process of cortisol-mediated CRH biosynthesis from rapid trans-synaptic effects that regulate the CRH secretion process. Crucially, we find that the slow regulation mechanism mediates external stress-driven transitions between the stable states in novel, intensity, duration, and timing-dependent ways. These results indicate that the timing of traumatic events may be an important factor in determining if and how patients will exhibit hallmarks of stress disorders. Our model also suggests a mechanism whereby exposure therapy of stress disorders such as PTSD may act to normalize downstream dysregulation of the HPA axis.Comment: 30 pages, 16 figures, submitted to BMC Biology Direc

Note su uguaglianza e differenza nella disciplina delle autonomie territoriali

Il tema oggetto delle presenti note si pone in linea di ideale proseguimento e sviluppo della riflessione svoltasi nell'ambito di un recente convegno, dedicato a Le disuguaglianze sostenibili nei sistemi autonomistici multilivello. L'idea di fondo, assunta a dato di base della riflessione comune, avvalorata da numerosi e recenti studi, anche di carattere monografico, muove dalla presa d'atto del superamento - sancito formalmente con la riforma del Titolo Quinto della Parte Seconda della Costituzione, ma all'esito di un dibattito che ha accompagnato il percorso dell'ordinamento post-unitario fin dalle sue origini (quando fu scartata l'opzione per il modello “della differenziazione” delle autonomie territoriali, sull'esempio austriaco) – del modello tradizionale di amministrazione locale che nella uniforme disciplina delle autonomie territoriali ricercava la garanzia dell'unità dell'ordinamento e, insieme, dell'eguale trattamento disciplinare degli amministrati su tutto il territorio nazionale. Un modello in cui l'uniformità era costruita ed intesa, pertanto, anche quale articolazione organizzativa dell'uguaglianza: mezzo e tecnica di garanzia di una uguaglianza formale che, tuttavia, consentiva e mascherava disuguaglianze sostanziali formidabili