420 research outputs found
Rise and fall of Achille de Giovanni\u2019s clinical anthropometry
Achille de Giovanni (1838-1916), Italian clinician and pathologist, developed a constitutional method for clinical investigations based on the morphology of the human body. He was the first to use anthropometry with living patients with the aim of evaluating the relationship between form and function, between organic structures, physiology and pathology, for understanding \u201cindividuality\u201d in a scientific way. His clinical anthropometry gained some popularity during his life, but was completely forgotten few decades after his death. By consequence, he can be considered a loser from the point of view of the long-term impact of his theories and practices, but at the same time, some of his ideas could be still valid today
Bernardino Ramazzini, three hundred years after his death, Padua (Italy), October 18th, 2014
open2noThe year 2014 has marked the tercentenary from the death of Bernardino Ramazzini (1633-1714), universally credited as the founder of Occupational Health (5, 9, 10, 11). Indeed, the renowned physician died on November 5th 1714 in Padua, where he had been appointed as Professor of Practical Medicine at the local prestigious University from the year 1700. To commemorate this anniversary, the professors of Occupational Health of the University of Padua, the Italian Society of Occupational Health and Industrial Hygiene (SocietĂ Italiana di Medicina del Lavoro eIgiene Industriale, SIMLII), the International Commission on Occupational Health (ICOH) and the University of Padua organized a conference in the wonderful location of Palazzo Bo (Main Hall) under the patronage of the Padua Municipality, the Workers' Compensation Authority (INAIL), the Venetian Region and the Societas Internationalis Historiae MedicinaopenRiva, Michele Augusto; Zampieri, FabioRiva, Michele Augusto; Zampieri, Fabi
Controllability Metrics, Limitations and Algorithms for Complex Networks
This paper studies the problem of controlling complex networks, that is, the
joint problem of selecting a set of control nodes and of designing a control
input to steer a network to a target state. For this problem (i) we propose a
metric to quantify the difficulty of the control problem as a function of the
required control energy, (ii) we derive bounds based on the system dynamics
(network topology and weights) to characterize the tradeoff between the control
energy and the number of control nodes, and (iii) we propose an open-loop
control strategy with performance guarantees. In our strategy we select control
nodes by relying on network partitioning, and we design the control input by
leveraging optimal and distributed control techniques. Our findings show
several control limitations and properties. For instance, for Schur stable and
symmetric networks: (i) if the number of control nodes is constant, then the
control energy increases exponentially with the number of network nodes, (ii)
if the number of control nodes is a fixed fraction of the network nodes, then
certain networks can be controlled with constant energy independently of the
network dimension, and (iii) clustered networks may be easier to control
because, for sufficiently many control nodes, the control energy depends only
on the controllability properties of the clusters and on their coupling
strength. We validate our results with examples from power networks, social
networks, and epidemics spreading
5mC-hydroxylase activity is influenced by the PARylation of TET1 enzyme
5-hydroxymethylcytosine is a new epigenetic modification deriving from the oxidation of 5-methylcytosine by the TET hydroxylase enzymes. DNA hydroxymethylation drives DNA demethylation events and is involved in the control of gene expression. Deregulation of TET enzymes causes developmental defects and is associated with pathological conditions such as cancer. Little information thus far is available on the regulation of TET activity by post-translational modifications. Here we show that TET1 protein is able to interact with PARP-1/ARTD1 enzyme and is target of both noncovalent and covalent PARylation. In particular, we have demonstrated that the noncovalent binding of ADP-ribose polymers with TET1 catalytic domain decreases TET1 hydroxylase activity while the covalent PARylation stimulates TET1 enzyme. In addition, TET1 activates PARP-1/ARTD1 independently of DNA breaks. Collectively, our results highlight a complex interplay between PARylation and TET1 which may be helpful in coordinating the multiple biological roles played by 5-hydroxymethylcytosine and TET proteins
Gossip consensus algorithms via quantized communication
This paper considers the average consensus problem on a network of digital
links, and proposes a set of algorithms based on pairwise ''gossip''
communications and updates. We study the convergence properties of such
algorithms with the goal of answering two design questions, arising from the
literature: whether the agents should encode their communication by a
deterministic or a randomized quantizer, and whether they should use, and how,
exact information regarding their own states in the update.Comment: Accepted for publicatio
Ultra Luminous X-ray Sources: a deeper insight into their spectral evolution
We select a sample of nearby Ultraluminous X-ray sources with long XMM-Newton
observations and analyse all the available XMM-Newton data using both X-ray
spectral fitting techniques and hardness-intensity diagrams. The sample
includes IC 342 X-1, NGC 5204 X-1, NGC 5408 X-1, Holmberg IX X-1, Holmberg II
X-1, NGC 1313 X-1, NGC 1313 X-2 and NGC 253 X-1. We found that, although a
common reference model can be used to describe the X-ray spectra, the sources
show different spectral evolutions, phenomenologically described in terms of
variations in the properties of a soft component and a high energy tail.
Variations at low energies are accounted for (mostly) by changes in the
normalization of the soft component and/or in the column density to the source,
while variations in the high energy tail by changes in the parameters of an
optically thick corona. This spectral variability is rather well characterized
on a colour-colour and hardness-intensity diagram in terms of suitably defined
hardness ratios. We suggest the existence of a variability pattern on the
hardness-intensity diagram and we interpret it in terms of the switch between a
near-Eddington and a super-Eddington accretion regime. The transition between
the two regimes seems to be driven mostly by changes in the contribution of the
soft component, which can be explained in terms of the increasing importance of
wind emission. The analysis is complemented by an investigation of the
short-term time variability of all the sources. In general, no clear
correlation between the spectral and temporal properties is found.Comment: 15 pages, 7 figures, 5 tables. Accepted for publication in MNRA
Galileo Galilei: Science vs. faith
Galileo Galilei (1564\u20131642), professor of mathematics at the University of Padua from 1592 to 1610, was a pillar in the history of our University and a symbol of freedom for research and teaching, well stated in the university motto \u2018\u2018Universa Universis Patavina Libertas\u2019\u2019 (Total freedom in Padua, open to all the world).1 He invented the experimental method, based on evidence and calculation (\u2018\u2018science is measure\u2019\u2019) and was able, by using the telescope, to confirm the Copernican heliocentric theory, a challenge to the Bible. Bertrand Russell (1872\u20131970), in his book \u2018\u2018The Problems of Philosophy\u2019\u2019 stated: \u2018\u2018Almost everything that distinguishes modern world from earlier centuries is attributable
to science, which achieved the most spectacular triumphs in the seventeenth century. Together with Harvey, Newton and Keplero, Galileo was a protagonist of this scientific revolution in the late Renaissance\u2019\u2019. His life was a continuous struggle to defend science from the influence of religious prejudices. He was catholic, forced by the Inquisition to deny his views, and was condemned to home arrest for the rest of his life. Here is the history of his life, a pendulum between science and religious beliefs
Andreas Vesalius: Celebrating 500 years of dissecting nature
December 31st, 2014 marked the 500-year anniversary of the birth of Andreas Vesalius. Vesalius, considered as the founder of modern anatomy, had profoundly changed not only human anatomy, but also the intellectual structure of medicine. The impact of his scientific revolution can be recognized even today. In this article we review the life, anatomical work, and achievements of Andreas Vesalius
DNA methylation dynamics in aging: How far are we from understanding the mechanisms?
DNA methylation is currently the most promising molecular marker for monitoring aging and predicting life expectancy. However, the mechanisms underlying age-related DNA methylation changes remain mostly undiscovered.Here we discuss the current knowledge of the dynamic nature of DNA epigenome landscape in mammals, and propose putative molecular mechanisms for aging-associated DNA epigenetic changes. Specifically, we describe age-related variations of methylcytosine and its oxidative derivatives in relation to the dynamics of chromatin structure, histone post-translational modifications and their modulators.Finally, we are proposing a conceptual framework that could explain the complex nature of the effects of age on DNA methylation patterns. This combines the accumulation of DNA methylation noise and also all of the predictable, site-specific DNA methylation changes.Gathering information in this area would pave the way for future investigation aimed at establishing a possible causative role of epigenetic mechanisms in aging
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