A replica free evaluation of the neuronal population information with mixed continuous and discrete stimuli: from the linear to the asymptotic regime

Recent studies have explored theoretically the ability of populations of neurons to carry information about a set of stimuli, both in the case of purely discrete or purely continuous stimuli, and in the case of multidimensional continuous angular and discrete correlates, in presence of additional quenched disorder in the distribution. An analytical expression for the mutual information has been obtained in the limit of large noise by means of the replica trick. Here we show that the same results can actually be obtained in most cases without the use of replicas, by means of a much simpler expansion of the logarithm. Fitting the theoretical model to real neuronal data, we show that the introduction of correlations in the quenched disorder improves the fit, suggesting a possible role of signal correlations-actually detected in real data- in a redundant code. We show that even in the more difficult analysis of the asymptotic regime, an explicit expression for the mutual information can be obtained without resorting to the replica trick despite the presence of quenched disorder, both with a gaussian and with a more realistic thresholded-gaussian model. When the stimuli are mixed continuous and discrete, we find that with both models the information seem to grow logarithmically to infinity with the number of neurons and with the inverse of the noise, even though the exact general dependence cannot be derived explicitly for the thresholded gaussian model. In the large noise limit lower values of information were obtained with the thresholded-gaussian model, for a fixed value of the noise and of the population size. On the contrary, in the asymptotic regime, with very low values of the noise, a lower information value is obtained with the gaussian model.Comment: 34 pages, 5 figure

Now there will be trouble

The paper considers sentences in which “now” occurs in initial position and shows that the meaning they convey differs from the meaning of sentences that are otherwise identical except for “now” occurring in final position. We argue that the occurrence of “now” in initial position triggers a particular kind of modal reading for the sentence to which the adverb is prefixed. A general notion of modal forcing is proposed to provide a uniform account of this kind of reading. Armed with this account, we offer a solution to two tense-modal puzzles, which have to do with fatalism and the possibility of a changing past

Stability of the Recovery of Missing Samples in Derivative Oversampling

This paper deals with the problem of reconstructing a band-limited signal when a finite subset of its samples and of its derivative are missing. The technique used, due to P.J.S.G. Ferreira, is based on the use of a particular frame for band-limited functions and the relative oversampling formulas. We study the eigenvalues of the matrices arising in the procedure of recovering the lost samples, finding estimates of their eigenvalues and their dependence on the oversampling parameter and on the number of missing samples. When the missing samples are consecutive, the problem may become very ill-conditioned. We present a numerical procedure to overcome this difficulty, also in presence of noisy data, by using Tikhonov regularization techniques.Comment: 17 pages,8 figure

Modality, presupposition and discourse

This paper provides a semantic analysis of the particles afinal (European Portuguese) and alla fine (Italian) in terms of the notion of truth unpersistence, which can be situated at the intersection of epistemic modality and discourse structure. In the analysis proposed, the particles are propositional operators and require that the truth of a proposition p* fail to persist through a temporal succession of epistemic states, this proposition being incompatible with the prejacent, and that the interlocutors share knowledge of a previous epistemic attitude toward p*. We analyze two main cases (plan-related and non plan-related propositions) and also show that these particles are indexical to one (or more) epistemic agent(s) and allow for shifts in perspective

Introduction

Introduction to genericity in the nominal, verbal and sentential domain

L'IMPRESA FARMACIA: DINAMICHE GESTIONALI IN TEMPO DI CRISI. IL CASO "FARMACIE SAS"

L’obbiettivo di questo lavoro è innanzitutto quello di analizzare la particolare configurazione dell’impresa farmacia, con riferimento al bene farmaco e alla sua distribuzione, al ruolo della farmacia nell’ambito del Servizio Sanitario Nazionale, alla gestione e titolarità della farmacia pubblica e privata e ai suoi aspetti economico-finanziari con specifico riguardo alla remunerazione del farmacista, al ciclo economico e monetario e al bilancio della farmacia. Dopo di che verrà posta l’attenzione sulla crisi del settore farmaceutico in Italia, analizzando i vari aspetti normativi e economici che hanno portato a tale situazione, nonché alle relative conseguenze sull’impresa farmacia e ai possibili rimedi nell’ambito delle procedure concorsuali. La terza parte del lavoro sarà focalizzata sulla determinazione del valore economico della farmacia, sul concordato preventivo e sul fallimento della stessa, con particolare attenzione a come si pongono entrambe le procedure rispetto al risanamento dell’impresa in crisi e alla conservazione dei valori aziendali. Verrà analizzata la continuità aziendale all’interno del concordato preventivo, l’esercizio provvisorio e la cessione d’azienda all’interno della procedura di fallimento, il caso particolare dell’affitto dell’azienda farmacia. Infine nel quarto capitolo verrà proposto il caso specifico di una società che gestisce 5 farmacie, la quale trovandosi in forte crisi economico-finanziaria, ha fatto ricorso alla procedura di concordato preventivo, ma successivamente è stata dichiarata fallita con la disposizione dell’esercizio provvisorio