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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
, let be the linear space of complex matrices, and let be functions whose components
belong to .
Consider the matrices , where varies
in and are the multilevel block Toeplitz matrices
of size generated by . Then
, i.e. the family
of matrices has a global (asymptotic)
spectral distribution described by the function , provided
possesses certain properties (which ensure in particular the invertibility of
for all ) and the following topological conditions are met:
the essential range of , defined as the union of the essential ranges
of the eigenvalue functions , 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 . 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;theresultwasconïŹrmedwithQFTfor13(0.62%)ofthem. Amongthe864postgraduate students,24(2.78%)hadapositiveTSTandonly18(2.08%)showedapositiveQTF.Latenttuberculosis infectionsweresigniïŹcantlymorefrequentamongpostgraduatesthanundergraduates(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 . We
derive the accretion rate from the mass of a spherical shell whose inner radius
is , 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 -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 , our prescription
returns an average MAR within of the average rate derived from the
merger trees of dark matter halos extracted from -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
La prigione nella memoria e la demitizzazione dellâeroico
The paper focuses on three masterpieces of the twentieth-century musical production â BĂšla BartĂłkâs Bluebeardâs Castle, Luigi Dellapiccolaâs The Prisoner and Arnold Schoenbergâs 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 è discutere la relazione fra la comparsa di termini antichi relativi alla teoria musicale e l’effettiva possibilità 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 è il ruolo della percezione all’interno di questa descrizione? Simha Arom’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 relationships between the occurrences of ancient terms connected to music theory and the strength possibility of description in modern music contexts. How can we use concepts like Talea, Color, Organum in the description of rhythmical structures conceived outside the western canonical theory? The Arom’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
Social cost of chronic pain in Italy
Chronic pain negatively impacts on sick people's daily life and their working ability, and it is a heavy financial burden on the health systems. This article is aimed at evaluating the social costs of chronic pain in Italy.The analysis is based on national tariffs and prices and on epidemiologic, health resource consumption, and absence from work published data; when no information specifically related to Italy was available, results from studies carried out in other European Countries were used as appropriate.The average annual cost per patient amounts to âŹ4,556, 31% of which (âŹ1,400) is charged on the National Health Service. Of this share, 51% is due to hospitalisation and 6% to analgesic drug (mostly NSAIDs) costs. Indirect costs (âŹ3,157) are caused by sickness leaves (31%) and retirements.Based on an estimated prevalence of 8 million people with pain in Italy, the impact of chronic pain direct costs on public health expenditure results 9.6%, whereas the impact of total costs on gross domestic product..
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