Impact of constrained rewiring on network structure and node dynamics

In this paper, we study an adaptive spatial network. We consider a susceptible-infected-susceptible (SIS) epidemic on the network, with a link or contact rewiring process constrained by spatial proximity. In particular, we assume that susceptible nodes break links with infected nodes independently of distance and reconnect at random to susceptible nodes available within a given radius. By systematically manipulating this radius we investigate the impact of rewiring on the structure of the network and characteristics of the epidemic.We adopt a step-by-step approach whereby we first study the impact of rewiring on the network structure in the absence of an epidemic, then with nodes assigned a disease status but without disease dynamics, and finally running network and epidemic dynamics simultaneously. In the case of no labeling and no epidemic dynamics, we provide both analytic and semianalytic formulas for the value of clustering achieved in the network. Our results also show that the rewiring radius and the network’s initial structure have a pronounced effect on the endemic equilibrium, with increasingly large rewiring radiuses yielding smaller disease prevalence

Majorana bound states in a coupled quantum-dot hybrid-nanowire system

Hybrid nanowires combining semiconductor and superconductor materials appear well suited for the creation, detection, and control of Majorana bound states (MBSs). We demonstrate the emergence of MBSs from coalescing Andreev bound states (ABSs) in a hybrid InAs nanowire with epitaxial Al, using a quantum dot at the end of the nanowire as a spectrometer. Electrostatic gating tuned the nanowire density to a regime of one or a few ABSs. In an applied axial magnetic field, a topological phase emerges in which ABSs move to zero energy and remain there, forming MBSs. We observed hybridization of the MBS with the end-dot bound state, which is in agreement with a numerical model. The ABS/MBS spectra provide parameters that are useful for understanding topological superconductivity in this system.Comment: Article and Supplementary Materia

Impact of boundaries on fully connected random geometric networks

Many complex networks exhibit a percolation transition involving a macroscopic connected component, with universal features largely independent of the microscopic model and the macroscopic domain geometry. In contrast, we show that the transition to full connectivity is strongly influenced by details of the boundary, but observe an alternative form of universality. Our approach correctly distinguishes connectivity properties of networks in domains with equal bulk contributions. It also facilitates system design to promote or avoid full connectivity for diverse geometries in arbitrary dimension.Comment: 6 pages, 3 figure

Transport signatures of quasiparticle poisoning in a Majorana island

We investigate effects of quasiparticle poisoning in a Majorana island with strong tunnel coupling to normal-metal leads. In addition to the main Coulomb blockade diamonds, "shadow" diamonds appear, shifted by 1e in gate voltage, consistent with transport through an excited (poisoned) state of the island. Comparison to a simple model yields an estimate of parity lifetime for the strongly coupled island (~ 1 {\mu}s) and sets a bound for a weakly coupled island (> 10 {\mu}s). Fluctuations in the gate-voltage spacing of Coulomb peaks at high field, reflecting Majorana hybridization, are enhanced by the reduced lever arm at strong coupling. In energy units, fluctuations are consistent with previous measurements.Comment: includes supplementary materia

Modularity and community detection in bipartite networks

The modularity of a network quantifies the extent, relative to a null model network, to which vertices cluster into community groups. We define a null model appropriate for bipartite networks, and use it to define a bipartite modularity. The bipartite modularity is presented in terms of a modularity matrix B; some key properties of the eigenspectrum of B are identified and used to describe an algorithm for identifying modules in bipartite networks. The algorithm is based on the idea that the modules in the two parts of the network are dependent, with each part mutually being used to induce the vertices for the other part into the modules. We apply the algorithm to real-world network data, showing that the algorithm successfully identifies the modular structure of bipartite networks.Comment: RevTex 4, 11 pages, 3 figures, 1 table; modest extensions to conten

Evaluation de l’effet repulsif d’extraits de neem (Azadirachta indica A. Juss., 1830) sur le charançon de la patate douce (Cylas puncticollis Boheman, 1833) en condition de laboratoire a Korhogo, nord de la Cote d’Ivoire

Une stratégie de gestion intégrée des insectes nuisibles à la culture de la patate douce a été élaborée pour réduire les pertes dues à ceux-ci. Ainsi, les propriétés répulsives des extraits de feuilles et d’amandes de neem ont été évaluées sur Cylas puncticollis, un charançon de la patate douce. Pour ce faire, quatre concentrations d’extraits ont été préparées à raison de quatre répétitions par concentration. Le test a consisté à la détermination du pourcentage de charançons présents dans la zone traitée. Chacune des concentrations d’extraits a été appliquée sur la moitié d’un papier buvard placé dans une boite de Pétri de 9 cm de diamètre et sur lequel 10 charançons ont été posés. Les effets répulsifs des extraits ont été comparés à ceux d’un insecticide chimique et l’eau distillée. Le test avec 20 cL/L d’extraits de feuilles a causé 85 % de répulsion contre 45 % pour les amandes à 25 g/L. Les extraits ont significativement causé plus de répulsion que l’eau distillée et l’insecticide chimique. Les tests ont révélé un potentiel plus répulsif des extraits de feuilles comparé à celui des amandes. Les extraits de neem pourraient constituer une alternative crédible à la lutte chimique pour la protection de la patate douce contre ce charançon. English title: Evaluation of the repellent effect of neem extracts (Azadirachta indica A. Juss., 1830) on the sweet potato weevil (Cylas puncticollis Boheman, 1833) under laboratory conditions in Korhogo, northern Côte d’Ivoire Abstract An integrated pest management strategy for sweet potatoes has been developed to reduce pest losses. Thus, the repellent properties of neem leaf and kernel extracts were evaluated on Cylas puncticollis, a sweet potato weevil. For this purpose, four concentrations of extracts were prepared with four replicates per concentration. The test consisted of determining the percentage of weevils in the treated area. Each of the extract concentrations was applied to half of a blotting paper placed in 9 cm diameter Petri dishes on which 10 weevils were placed. The repellent effects of the extracts were compared to those of a chemical insecticide and distilled water. Test with 20 cL/L leaf extract caused 85% repellence compared to 45% for almonds at 25 g/L. Compared to the chemical insecticide and distilled water, the extracts caused significantly more repellence. The tests revealed a higher repellent potential of the leaf extracts compared to those of almonds. Neem extracts could be a credible alternative to chemical control for the protection of sweet potato against this weevil. Keywords: Neem extracts, Repellent effect, Sweet potato, Cylas puncticolli

Multiple Nuclear Polarization States in a Double Quantum Dot

We observe multiple stable states of nuclear polarization in a double quantum dot under conditions of electron spin resonance. The stable states can be understood within an elaborated theoretical rate equation model for the polarization in each of the dots, in the limit of strong driving. This model also captures unusual features of the data, such as fast switching and a `wrong' sign of polarization. The results reported enable applications of this polarization effect, including manipulation and control of nuclear fields.Comment: 5 pages, 4 figures, 7 pages supplementary materia

Genes adopt non-optimal codon usage to generate cell cycle-dependent oscillations in protein levels

Most cell cycle-regulated genes adopt non-optimal codon usage, namely, their translation involves wobbly matching codons. Here, the authors show that tRNA expression is cyclic and that codon usage, therefore, can give rise to cell-cycle regulation of proteins

Bloggers Behavior and Emergent Communities in Blog Space

Interactions between users in cyberspace may lead to phenomena different from those observed in common social networks. Here we analyse large data sets about users and Blogs which they write and comment, mapped onto a bipartite graph. In such enlarged Blog space we trace user activity over time, which results in robust temporal patterns of user--Blog behavior and the emergence of communities. With the spectral methods applied to the projection on weighted user network we detect clusters of users related to their common interests and habits. Our results suggest that different mechanisms may play the role in the case of very popular Blogs. Our analysis makes a suitable basis for theoretical modeling of the evolution of cyber communities and for practical study of the data, in particular for an efficient search of interesting Blog clusters and further retrieval of their contents by text analysis