Super-spreading Events and Contribution to Transmission of MERS, SARS, and COVID-19

There is no clear definition for the term ‘super-spreader’ or ‘super-spreading event’. The World Health Organization refers to a super-spreader as a patient (or an event) that may transmit infection to a larger number of individuals than is usual by one individual (or event). In the severe acute respiratory syndrome (SARS) situation, a super-spreading event was defined as the transmission of SARS to at ≥8 contacts, and other authors defined this as individuals infecting an unusually large number of secondary cases [ 1 , 2 ]. A super-spreading event could merely be defined as an event in which one patient infects far more people than an average patient does, which is estimated by the basic reproduction number (R0)

Controlled nucleation of topological defects in the stripe domain patterns of Lateral multilayers with Perpendicular Magnetic Anisotropy: competition between magnetostatic, exchange and misfit interactions

Magnetic lateral multilayers have been fabricated on weak perpendicular magnetic anisotropy amorphous Nd-Co films in order to perform a systematic study on the conditions for controlled nucleation of topological defects within their magnetic stripe domain pattern. A lateral thickness modulation of period $w$ is defined on the nanostructured samples that, in turn, induces a lateral modulation of both magnetic stripe domain periods $\lambda$ and average in-plane magnetization component $M_{inplane}$. Depending on lateral multilayer period and in-plane applied field, thin and thick regions switch independently during in-plane magnetization reversal and domain walls are created within the in-plane magnetization configuration coupled to variable angle grain boundaries and disclinations within the magnetic stripe domain patterns. This process is mainly driven by the competition between rotatable anisotropy (that couples the magnetic stripe pattern to in-plane magnetization) and in-plane shape anisotropy induced by the periodic thickness modulation. However, as the structural period $w$ becomes comparable to magnetic stripe period $\lambda$, the nucleation of topological defects at the interfaces between thin and thick regions is hindered by a size effect and stripe domains in the different thickness regions become strongly coupled.Comment: 10 pages, 7 figures, submitted to Physical Review

Direct and Heterodyne Detection of Microwaves in a Metallic Single Wall Carbon Nanotube

This letter reports measurements of microwave (up to 4.5 GHz) detection in metallic single-walled carbon nanotubes. The measured voltage responsivity was found to be 114 V/W at 77K. We also demonstrated heterodyne detection at 1 GHz. The detection mechanism can be explained based on standard microwave detector theory and the nonlinearity of the DC IV-curve. We discuss the possible causes of this nonlinearity. While the frequency response is limited by circuit parasitics in this measurement, we discuss evidence that indicates that the effect is much faster and that applications of carbon nanotubes as terahertz detectors are feasible

Optimizing Scan Homogeneity for Building Full-3D Lidars based on Rotating a Multi-Beam Velodyne Rangefinder

Multi-beam lidar (MBL) scanners are compact, light, and accessible 3D sensors with high data rates, but they offer limited vertical resolution and field of view (FOV). Some recent robotics research has profited from the addition of a degree-of-freedom (DOF) to an MBL to build rotating multi-beam lidars (RMBL) that can achieve high-resolution scans with full spherical FOV. In a previous work, we offered a methodology to analyze the complex 3D scan measurement distributions produced by RMBLs with a rolling DOF and no pitching. In this paper, we investigate the effect of introducing constant pitch angles in the construction of the RMBLs with the purpose of finding a kinematic configuration that optimizes scan homogeneity with a spherical FOV. To this end, we propose a scalar index of 3D sensor homogeneity that is based on the spherical formulation of Ripley's K function. The optimization is performed for the widely used Puck (VLP-16) and HDL-32 sensors by Velodyne.This work was partially funded by the Spanish project {DPI2015-65186-R}. The publication has received support from Universidad de Málaga, Campus de Excelencia Andalucía Tech

An Experiment on the Neolithic Agricultural Revolution. Causes and Impact on Inequality

Testing causal relationships expressed by mathematical models on facts about human behaviour across history is challenging. A prominent example is the Neolithic agricultural revolution [1]. Many theoretical models of the adoption of agriculture has been put forward [2] but none has been tested. The only exception is [3], that uses a computational approach with agent-based simulations of evolutionary games. Here, we propose two games that resemble the conditions of human societies before and after the agricultural revolution. The agricultural revolution is modelled as an exogenous shock in the lab (n=180, 60 independent groups), and the transition from foraging to farming results from an equilibrium selection process decided by experimental subjects. The experimental data replicate the known facts that foragers organized themselves around division of labour [4] and were more egalitarian than farmers [5]. There is also evidence of bi-modal distribution along the foraging-farming axis with many in-between groups [6, 7, 8]. These results provide direct evidence that the modes of production determine the system of values of societies (inequality) and lend support for the idea that human moved in a widespread manner from foraging to farming societies. We also find that cultural and institutional preconditions were crucial for farming [9], as more egalitarian foraging groups adopted earlier agricultural techniques, but inequality raises in farming societies as agriculture settles [10], with the long run success of agriculture being determined by the land-owner’s legitimacy. These results enrich our understanding of the Neolithic agricultural revolution and highlight the relevance of experimental methodology to generate a rich dataset that complements the fragmented evidence from archaeological sites

Emergence of COVID-19 (formerly 2019-novel Coronavirus): a new threat from China

Coronaviruses cause diseases in birds, mammals, and humans, and were first identified in the mid-1960s (Lee, 2015; Bande et al., 2015; CDC, 2020). These viruses are named for the crown-like spikes on their surface (CDC, 2020). Based on the classification of the International Committee for Taxonomy of Viruses (ICTV) coronaviruses are from order Nidovirales, family Coronaviridae and subfamily Coronavirinae. The viruses contain a positive sense, single-stranded Ribonucleic acid (RNA) genome ranged from 26 to 32 kilobases (kb) in length and thus have the largest genomes for RNA viruses (van Regenmortel et al., 2000). These viruses are further divided into four main subgroups named alpha, beta, gamma, and delta. There are seven human coronaviruses cause infection in humans including 229E (alpha coronavirus), NL63 (alpha coronavirus), OC43 (beta coronavirus), HKU1 (beta coronavirus), Middle East Respiratory Syndrome, or MERS (beta coronavirus), Severe Acute Respiratory Syndrome, or SARS (beta coronavirus), and the newly identified 2019 Novel Coronavirus (2019-nCoV) (CDC, 2020). Common symptoms of the disease include fever, cough, respiratory symptoms, shortness of breath and breathing difficulties (WHO, 2020)