1,721,024 research outputs found
A case of complex matter: Coexistence of multiple phase separation in cuprates
No full textNato Sciente Series II Mathematics, Physics and Chemistr
Sars-Cov2 world pandemic recurrent waves controlled by variants evolution and vaccination campaign
Full text linkWhile understanding the time evolution of Covid-19 pandemic is needed to plan economics and tune sanitary policies, a quantitative information of the recurrent epidemic waves is elusive. This work describes a statistical physics study of the subsequent waves in the epidemic spreading of Covid-19 and disclose the frequency components of the epidemic waves pattern over two years in United States, United Kingdom and Japan. These countries have been taken as representative cases of different containment policies such as "Mitigation" (USA and UK) and "Zero Covid" (Japan) policies. The supercritical phases in spreading have been identified by intervals with RIC-index > 0. We have used the wavelet transform of infection and fatality waves to get the spectral analysis showing a dominant component around 130 days. Data of the world dynamic clearly indicates also the crossover to a different phase due to the enforcement of vaccination campaign. In Japan and United Kingdom, we observed the emergence in the infection waves of a long period component (~ 170 days) during vaccination campaign. These results indicate slowing down of the epidemic spreading dynamics due to the vaccination campaign. Finally, we find an intrinsic difference between infection and fatality waves pointing to a non-trivial variation of the lethality due to different gene variants
Epidemic spreading in an expanded parameter space: the supercritical scaling laws and subcritical metastable phases
Full text linkWhile the mathematical laws of uncontrolled epidemic spreading are well known, the statistical physics of coronavirus epidemics with containment measures is currently lacking. The modelling of available data of the first wave of the Covid-19 pandemic in 2020 over 230 days, in different countries representative of different containment policies is relevant to quantify the efficiency of these policies to face the containment of any successive wave. At this aim we have built a 3D phase diagram tracking the simultaneous evolution and the interplay of the doubling time, T (d), and the reproductive number, R (t) measured using the methodological definition used by the Robert Koch Institute. In this expanded parameter space three different main phases, supercritical, critical and subcritical are identified. Moreover, we have found that in the supercritical regime with R (t) > 1 the doubling time is smaller than 40 days. In this phase we have established the power law relation between T (d) and (R (t) - 1)(-nu) with the exponent nu depending on the definition of reproductive number. In the subcritical regime where R (t) < 1 and T (d) > 100 days, we have identified arrested metastable phases where T (d) is nearly constant
Efficiency of COVID-19 mobile contact tracing containment by measuring time-dependent doubling time
Full text linkThe COVID-19 epidemic of the novel coronavirus (severe acute respiratory syndrome SARS-CoV-2) has spread around the world. While different containment policies using non-pharmaceutical interventions have been applied, their efficiencies are not known quantitatively. We show that the doubling timeT(d)(t) with the successs factor, the characteristic time of the exponential growth ofT(d)(t) in the arrested regime, is a reliable tool for early predictions of epidemic spread time evolution and provides a quantitative measure of the success of different containment measures. The efficiency of the containment policylockdown case finding mobile tracing(LFT) using mandatory mobile contact tracing is much higher than that of thelockdown stop and gopolicy proposed by the Imperial College team in London. A very lowsfactor was reached by the LFT policy, giving the shortest time width of the positive case curve and the lowest number of fatalities. The LFT policy was able to reduce the number of fatalities by a factor of 100 in the first 100 d of the COVID-19 epidemic, reduce the time width of the COVID-19 pandemic curve by a factor 2.5, and rapidly stop new outbreaks and thereby avoid a second wave to date
Myelin basic protein dynamics from out-of-equilibrium functional state to degraded state in myelin
No full textLiving matter is a quasi-stationary out-of-equilibrium system; in this physical condition, structural fluctuations at nano- and meso-scales are needed to understand the physics behind its biological functionality. Myelin has a simple ultrastructure whose fluctuations show correlated disorder in its functional out-of-equilibrium state. However, there is no information on the relationship between this correlated disorder and the dynamics of the intrinsically disordered Myelin Basic Protein (MBP) which is expected to influence the membrane structure and overall functionality. In this work, we have investigated the role of this protein structural dynamics in the myelin ultrastructure fluctuations in various conditions, by using synchrotron Scanning micro X Ray Diffraction and Small Angle X ray Scattering. We have induced the crossover from out-of-equilibrium functional state to in-equilibrium degeneration changing the pH to values far from physiological condition.The observed compression of the cytosolic layer thickness probes that the intrinsic large MBP fluctuations preserve the cytosol structure also in the degraded state. Thus, the transition of myelin ultrastructure from correlated to uncorrelated disordered state, is principally affected by the deformation of the membrane and extracellular domain
Controlling Photoinduced Electron Transfer Via Defects Self-Organization for Novel Functional Macromolecular Systems
No full textCommon features in high Tc cuprates and diborides
No full textThe features of the normal state of cuprate superconductors, that drive up the Tc from the low temperature range TcTbH, i.e., the “smoking gun” for the “high-Tc” has not been found even after 18 years from the discovery of the superconductivity in these complex doped Mott insulators. Magnesium diboride provides a superconductor with Tc>TbH that has a normal phase well described by the standard solid state theory. Therefore it provides the simplest system for the “high Tc superconductivity” as the atomic hydrogen was the simplest system for the “quantum mechanics”. Here we show that the normal state of the magnesium diboride shows key features, that are in common with cuprates, and shed light on the pairing mechanism for Tc amplification in the high-Tc superconductors
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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