Social Distancing Causally Impacts the Spread of SARS-CoV-2: A U.S. Nationwide Event Study

We assess the causal impact of a spontaneous relaxation of social distancing practices on the spread of SARS-CoV-2 in the U.S., while controlling for social mobility and state-imposed social distancing restrictions. Using the quasi-experimental setting created by the U.S. nationwide protests precipitated by George Floyd’s tragic death on May 25, 2020, we document a country-wide increase of over 3·06 cases per day, per 100,000 population, following the onset of the protests (95% CI:2·47–3·65), and a further in-crease of 1·73 cases per day, per 100,000 population, in the counties in which the protests took place (95% CI:0·59–2·87). Relative to the week preceding the onset of the protests, this represents a 61·2% country-wide increase in COVID-19 cases, and a further 34·6% increase in the protest counties. Hence, we conclude that social distancing practices causally impact the spread of SARS-CoV-2. The observed effect cannot be explained by changes in social distancing restrictions and social mobility, and our placebo tests rule out the possibility that this finding is attributable to chance. Our research informs policy makers and provides insights regarding the usefulness of social distancing as an intervention to minimize the spread of SARS-CoV-2.

Bending-torsional elasticity and energetics of the plus-end microtubule tip

Microtubules (MTs), mesoscopic cellular filaments, grow primarily by the addition of GTP-bound tubulin dimers at their dynamic flaring plus-end tips. They operate as chemomechanical energy transducers with stochastic transitions to an astounding shortening motion upon hydrolyzing GTP to GDP. Time-resolved dynamics of the MT tip - a key determinant of this behavior - as a function of nucleotide state, internal lattice strain, and stabilizing lateral interactions have not been fully understood. Here, we use atomistic simulations to study the spontaneous relaxation of complete GTP-MT and GDP-MT tip models from unfavorable straight to relaxed splayed conformations and to comprehensively characterize the elasticity of MT tips. Our simulations reveal the dominance of viscoelastic dynamics of MT protofilaments during the relaxation process, driven by the stored bending-torsional strain and counterbalanced by the inter-protofilament interactions. We show that the post-hydrolysis MT tip is exposed to higher activation energy barriers for straight lattice formation, which translates into its inability to elongate. Our study provides an 'information ratchet' mechanism for the elastic energy conversion and release by MT tips and offers new insights into the mechanoenzymatics of MTs.

Симметрия икосаэдра и оптические свойства фуллерена С-=SUB=-60-=/SUB=-

The electron transitions property of the fullerene molecule is considered. Because of electron jumps between nearest neighbor is possible, the interaction of the $\pi$- electrons produces the appearance of the collective states, having truncated icosahedron symmetry. The irreducible representations of the icosahedral group allow us to subdivide the state functions into groups with separate energy sublevel. The good approximation of the wave functions for the irreducible representations developed by means of spherical functions superposition. The optical properties is presented by formula of the excitation cross-section for electronic levels and by formula of the spontaneous relaxation time, received with help of matrix element calculation. Because of Jahn–Teller effect, a time of non-radiative transition is much less than radiative relaxation time. The interaction with phonon spectrum produces the spontaneously broken symmetry and restricts electronic-emission spectrum, while the absorption in optical spectrum exists. Transfer of energy from electron states into phonon oscillations produces the thermal radiation. However, it is possible to solve problem of electron state decay.

Prototype Material for New Strategy of Photon Energy Storage

The smart utilization of photons is paid global attention from the viewpoint of renewable energy and information technology. However, it is still impossible to store photons as batteries and condensers do for electrons. All the present technologies utilize (the energy of) photons in situ, such as solar panels, or in spontaneous relaxation processes, such as photoluminescence. If we can store the energy of photons over an arbitrary period and utilize them on demand, not only we will make an innovative progress in energy management, but we will also be able to replace a part of electrons by photons in the information technology for more efficient performance. In this article, we review a prototype of such a material including the current status of related research as well as where we are heading for.

Social Distancing Causally Impacts the Spread of SARS-CoV-2: A U.S. Nationwide Event Study

ObjectivesTo assess the causal impact of a spontaneous relaxation of social distancing on the spread of SARS-CoV-2 in the United States (U.S.), while controlling for social mobility and state-imposed social distancing restrictions.DesignEvent study.SettingQuasi-experimental setting created by the U.S. nationwide protests precipitated by George Floyd’s tragic death on May 25, 2020.PopulationIndividuals in 3,142 U.S. counties from all 50 states and the District of Columbia.Main Outcome MeasuresThe number of daily confirmed COVID-19 cases in all U.S. counties between the period of January 22, 2020, and June 20, 2020, and the cumulative change in COVID-19 cases in protest counties relative to non-protest counties following the onset of the protests.ResultsWe document a country-wide increase of over 3·06 cases per day, per 100,000 population, following the onset of the protests (95%CI: 2·47–3·65), and a further increase of 1·73 cases per day, per 100,000 population, in the counties in which the protests took place (95%CI: 0·59–2·87). Relative to the week preceding the onset of the protests, this represents a 61·2% country-wide increase in COVID-19 cases, and a further 34·6% increase in the protest counties.ConclusionsOur study documents a significant increase in COVID-19 case counts in counties that experienced a protest, and we conclude that social distancing practices causally impact the spread of SARS-CoV-2. The observed effect cannot be explained by changes in social distancing restrictions and social mobility, and placebo tests rule out the possibility that this finding is attributable to chance. Our research informs policy makers and provides insights regarding the usefulness of social distancing as an intervention to minimize the spread of SARS-CoV-2.

Recycling of energy dissipated as heat accounts for high activity of Photosystem II

ABSTRACTPhotosystem II (PSII) converts light into chemical energy powering almost entire life on Earth. The primary photovoltaic reaction in the PSII reaction centre requires energy corresponding to 680 nm that is significantly higher than in the case of the low-energy states in the antenna complexes involved in the harvesting of excitations driving PSII. Here we show that despite seemingly insufficient energy, the low-energy excited states can power PSII thanks to the activity of the thermally-driven up-conversion. We demonstrate the operation of this mechanism both in intact leaves and in isolated pigment-protein complex LHCII. A mechanism is proposed, according to which the effective utilization of thermal energy in the photosynthetic apparatus is possible owing to the formation of LHCII supramolecular structures, leading to the coupled energy levels, corresponding to approx. 680 nm and 700 nm, capable of exchanging excitation energy through the spontaneous relaxation and the thermal up-conversion.TOC GRAPHICS