Nutrition, Epigenetics, and Diseases

Increasing epidemiological evidence suggests that maternal nutrition and environmental exposure early in development play an important role in susceptibility to disease in later life. In addition, these disease outcomes seem to pass through subsequent generations. Epigenetic modifications provide a potential link between the nutrition status during critical periods in development and changes in gene expression that may lead to disease phenotypes. An increasing body of evidence from experimental animal studies supports the role of epigenetics in disease susceptibility during critical developmental periods, including periconceptional period, gestation, and early postnatal period. The rapid improvements in genetic and epigenetic technologies will allow comprehensive investigations of the relevance of these epigenetic phenomena in human diseases

Spectral behavior of preconditioned non-Hermitian multilevel block Toeplitz matrices with matrix-valued symbol

This note is devoted to preconditioning strategies for non-Hermitian multilevel block Toeplitz linear systems associated with a multivariate Lebesgue integrable matrix-valued symbol. In particular, we consider special preconditioned matrices, where the preconditioner has a band multilevel block Toeplitz structure, and we complement known results on the localization of the spectrum with global distribution results for the eigenvalues of the preconditioned matrices. In this respect, our main result is as follows. Let $I_k:=(-\pi,\pi)^k$, let $\mathcal M_s$ be the linear space of complex $s\times s$ matrices, and let $f,g:I_k\to\mathcal M_s$ be functions whose components $f_{ij},\,g_{ij}:I_k\to\mathbb C,\ i,j=1,\ldots,s,$ belong to $L^\infty$. Consider the matrices $T_n^{-1}(g)T_n(f)$, where $n:=(n_1,\ldots,n_k)$ varies in $\mathbb N^k$ and $T_n(f),T_n(g)$ are the multilevel block Toeplitz matrices of size $n_1\cdots n_ks$ generated by $f,g$. Then $\{T_n^{-1}(g)T_n(f)\}_{n\in\mathbb N^k}\sim_\lambda g^{-1}f$, i.e. the family of matrices $\{T_n^{-1}(g)T_n(f)\}_{n\in\mathbb N^k}$ has a global (asymptotic) spectral distribution described by the function $g^{-1}f$, provided $g$ possesses certain properties (which ensure in particular the invertibility of $T_n^{-1}(g)$ for all $n$) and the following topological conditions are met: the essential range of $g^{-1}f$, defined as the union of the essential ranges of the eigenvalue functions $\lambda_j(g^{-1}f),\ j=1,\ldots,s$, does not disconnect the complex plane and has empty interior. This result generalizes the one obtained by Donatelli, Neytcheva, Serra-Capizzano in a previous work, concerning the non-preconditioned case $g=1$. The last part of this note is devoted to numerical experiments, which confirm the theoretical analysis and suggest the choice of optimal GMRES preconditioning techniques to be used for the considered linear systems.Comment: 18 pages, 26 figure

Latent Tuberculosis Infection among Healthcare Students and Postgraduates in a Mediterranean Italian Area: What Correlation with Work Exposure?

Background: Tuberculosis screening is part of the standard protocol for evaluating the risk of infection in healthcare workers. The aim of this study was to evaluate the prevalence of latent tuberculosis infection (LTBI) among students attending various healthcare profession degree courses and postgraduate medical courses at the School of Medicine of the University of Palermo, Italy, and assess the possible professional origin of infection. Methods: In total, 2946 students (2082 undergraduates and 864 postgraduates) took part in a screening program for LTBI between January 2014 to April 2019 using the tuberculin skin test (TST). Students with a positive TST result underwent a Quantiferon-TB test (QFT). Results: Among the 2082 undergraduates, 23 (1.1%) had a positiveTST;theresultwasconfirmedwithQFTfor13(0.62%)ofthem. Amongthe864postgraduate students,24(2.78%)hadapositiveTSTandonly18(2.08%)showedapositiveQTF.Latenttuberculosis infectionsweresignificantlymorefrequentamongpostgraduatesthanundergraduates(2.08% > 0.62%, p < 0.0001). There was a higher number of subjects previously vaccinated for TB (18.87% > 0.24%, p < 0.0001), and of vaccinated subjects found positive for TST and QTF (66.67% > 7.69%, p = 0.001) in the postgraduate group. Conclusion: Latent TB is relatively low among medical school students in our geographic area. Nevertheless, this infectious disease must be regarded as a re-emerging biohazard for which preventive strategies are required to limit the risk of infection, especially among exposed workers

The mass accretion rate of galaxy clusters: a measurable quantity

We explore the possibility of measuring the mass accretion rate (MAR) of galaxy clusters from their mass profiles beyond the virial radius $R_{200}$. We derive the accretion rate from the mass of a spherical shell whose inner radius is $2R_{200}$, whose thickness changes with redshift, and whose infall velocity is assumed to be equal to the mean infall velocity of the spherical shells of dark matter halos extracted from $N$-body simulations. This approximation is rather crude in hierarchical clustering scenarios where both smooth accretion and aggregation of smaller dark matter halos contribute to the mass accretion of clusters.Nevertheless, in the redshift range $z=[0,2]$, our prescription returns an average MAR within $20-40 \%$ of the average rate derived from the merger trees of dark matter halos extracted from $N$-body simulations. The MAR of galaxy clusters has been the topic of numerous detailed numerical and theoretical investigations, but so far it has remained inaccessible to measurements in the real universe. Since the measurement of the mass profile of clusters beyond their virial radius can be performed with the caustic technique applied to dense redshift surveys of the cluster outer regions, our result suggests that measuring the mean MAR of a sample of galaxy clusters is actually feasible. We thus provide a new potential observational test of the cosmological and structure formation models.Comment: 11 pages, 7 figures, 5 tables, minor text modifications to match the published version, typos correcte

Codon and Reverse Codon: A Theoretical Approach to Reinterpret the Genetic Code Table

The genetic code table represents a fundamental scheme to translate a genetic code into a sequence of amino acids and, therefore, the possibility of operating the synthesis of all the proteins necessary for the life of organisms. Unfortunately, the various biological mechanisms are not fully clear. Hence, in this report, we analyzed the genetic code table and the amino acids codified by codons with an original theoretical and statistical approach based on the concept of permutations. We found an interesting reinterpretation of many codons, as reverse codons, which could help clarify some as-yet-unknown aspects in the field of protein folding

Analysis of Concurrent and Correlated Stirring Mechanisms in Reverberation Chambers

A new multivariate statistical analysis is proposed to derive the estimates of effective sample sizes of reverberation chamber (RC) measurement data. Concurrent correlation effects, related to different and simultaneously acting stirring mechanisms, are taken into account and individually quantified. The mean and variance of correlated measurement data are also estimated, as well as the variance of the grand mean. The analysis is independent on the parent probability distributions. Formulae are obtained through a step-by-step derivation, stemming from basic statistical principles and general assumptions, which are deemed to be applicable to the correlation structures of RC measurement data. Experiments and comparison with closed-form predictions confirm the validity and generality of the analysis.</p

Recensione a Morton Feldman

Recensione a Morton feldma

La prigione nella memoria e la demitizzazione dell’eroico

The paper focuses on three masterpieces of the twentieth-century musical production – Bèla Bartók’s Bluebeard’s Castle, Luigi Dellapiccola’s The Prisoner and Arnold Schoenberg’s A Survivor from Warsaw. In these, the central theme of captivity is made more lively thanks to the expressive power of a dreamlike setting. The purpose is to depict the relation between the dimensions of memory and dream, for that generation of composers who witnessed the transition between the two world conflicts, which dramatically marked the last century, and the political instability that followed or anticipated them.

Terminologia tecnica e riappropriazione concettuale: le polifonie medievali come laboratorio compositivo

Gli studi di Simha Arom sulla polifonia africana ha avuto un notevole impatto sulla cultura occidentale, in modo particolare con riferimento alla teoria ritmica della composizione. Scopo principale di questo studio &egrave; discutere la relazione fra la comparsa di termini antichi relativi alla teoria musicale e l&rsquo;effettiva possibilit&agrave; di descriverli in contesti musicali moderni.In che modo si possono usare concetti come talea, color, organum nella descrizione di strutture ritmiche concepite al di fuori della teoria canonica occidentale? Gli scritti di Arom mostrano come oggi sia ancora possibile individuare un nesso tra modelli africani di scansione ritmica e il concetto occidentale di dissonanza temporale: ma qual &egrave; il ruolo della percezione all&rsquo;interno di questa descrizione?&nbsp;Simha Arom&rsquo;s Studies in African Polyphony had a great impact in Western Culture, especially inside the Rhythmic Theory of Composition: the main aim of this work is a discussion about the&nbsp; relationships between the occurrences&nbsp; of&nbsp; ancient terms connected to music theory and the strength possibility of description&nbsp; in modern music contexts. How can we use concepts like Talea, Color, Organum in the description of rhythmical structures conceived outside the western canonical&nbsp; theory? The Arom&rsquo;s writings show us that today is still possible to establish a link between African models of Rhythmical periods and the Western Concept of temporal dissonance: but what is the role of perception inside this description