Formation Energies of Antiphase Boundaries in GaAs and GaP: An ab Initio Study

Electronic and structural properties of antiphase boundaries in group III-V semiconductor compounds have been receiving increased attention due to the potential to integration of optically-active III-V heterostructures on silicon or germanium substrates. The formation energies of {110}, {111}, {112}, and {113} antiphase boundaries in GaAs and GaP were studied theoretically using a full-potential linearized augmented plane-wave density-functional approach. Results of the study reveal that the stoichiometric {110} boundaries are the most energetically favorable in both compounds. The specific formation energy γ of the remaining antiphase boundaries increases in the order of γ{113} ≈ γ{112} < γ{111}, which suggests {113} and {112} as possible planes for faceting and annihilation of antiphase boundaries in GaAs and GaP

A two-strain model of infectious disease spread with asymmetric temporary immunity periods and partial cross-immunity

We introduce a two-strain model with asymmetric temporary immunity periods and partial cross-immunity. We derive explicit conditions for competitive exclusion and coexistence of the strains depending on the strain-specific basic reproduction numbers, temporary immunity periods, and degree of cross-immunity. The results of our bifurcation analysis suggest that, even when two strains share similar basic reproduction numbers and other epidemiological parameters, a disparity in temporary immunity periods and partial or complete cross-immunity can provide a significant competitive advantage. To analyze the dynamics, we introduce a quasi-steady state reduced model which assumes the original strain remains at its endemic steady state. We completely analyze the resulting reduced planar hybrid switching system using linear stability analysis, planar phase-plane analysis, and the Bendixson-Dulac criterion. We validate both the full and reduced models with COVID-19 incidence data, focusing on the Delta (B.1.617.2), Omicron (B.1.1.529), and Kraken (XBB.1.5) variants. These numerical studies suggest that, while early novel strains of COVID-19 had a tendency toward dramatic takeovers and extinction of ancestral strains, more recent strains have the capacity for co-existence.Comment: 29 pages, 18 figure

Selective deletion of cochlear hair cells causes rapid age-dependent changes in spiral ganglion and cochlear nucleus neurons

During nervous system development, critical periods are usually defined as early periods during which manipulations dramatically change neuronal structure or function, whereas the same manipulations in mature animals have little or no effect on the same property. Neurons in the ventral cochlear nucleus (CN) are dependent on excitatory afferent input for survival during a critical period of development. Cochlear removal in young mammals and birds results in rapid death of target neurons in the CN. Cochlear removal in older animals results in little or no neuron death. However, the extent to which hair-cell-specific afferent activity prevents neuronal death in the neonatal brain is unknown. We further explore this phenomenon using a new mouse model that allows temporal control of cochlear hair cell deletion. Hair cells express the human diphtheria toxin (DT) receptor behind the Pou4f3 promoter. Injections of DT resulted in nearly complete loss of organ of Corti hair cells within 1 week of injection regardless of the age of injection. Injection of DT did not influence surrounding supporting cells directly in the sensory epithelium or spiral ganglion neurons (SGNs). Loss of hair cells in neonates resulted in rapid and profound neuronal loss in the ventral CN, but not when hair cells were eliminated at a more mature age. In addition, normal survival of SGNs was dependent on hair cell integrity early in development and less so in mature animals. This defines a previously undocumented critical period for SGN survival

Computational screening of cathode materials for Zn-ion rechargeable batteries

We propose a comprehensive set of indicators (including methods to obtain and analyse them) for computational screening of candidate cathode materials for rechargeable Zn-ion aqueous batteries relying on Zn$^{2+}$ intercalation processes. The indicators capture feasibility of Zn$^{2+}$ intercalation and transport within the material, the thermodynamic stability of charged and discharged material structures, electrochemical stability of the cathode material and electrolyte, volume expansion, and energy storage capacity. The approach was applied to well-known cathode materials ($\alpha$-MnO$_2$ and V$_2$O$_5$) as well as some potential alternatives (MoS$_2$, ZrP$_2$O$_7$, MoO$_3$, and FeO$_2$). We show that selection of cathode materials for Zn-ion aqueous rechargeable batteries is a multifaceted problem, and first principle calculations can help to narrow down the search. Despite us being unable to identify a particularly successful cathode material, tools and techniques developed in this work can be applied more broadly to screen a wider array of potential material compositions and structures, with the goal of identifying next generation cathode materials for aqueous rechargeable batteries with the intercalation energy storage mechanism not limited to Zn$^{2+}$ ions.Comment: 36 pages, 8 figures, 5 table

Universal Continuous Variable Quantum Computation in the Micromaser

We present universal continuous variable quantum computation (CVQC) in the micromaser. With a brief history as motivation we present the background theory and define universal CVQC. We then show how to generate a set of operations in the micromaser which can be used to achieve universal CVQC. It then follows that the micromaser is a potential architecture for CVQC but our proof is easily adaptable to other potential physical systems.Comment: 12 pages, 4 figures, accepted for a presentation at the 9th International Conference on Unconventional Computation (UC10) and LNCS proceedings

Analytical model of brittle destruction based on hypothesis of scale similarity

The size distribution of dust particles in nuclear fusion devices is close to the power function. A function of this kind can be the result of brittle destruction. From the similarity assumption it follows that the size distribution obeys the power law with the exponent between -4 and -1. The model of destruction has much in common with the fractal theory. The power exponent can be expressed in terms of the fractal dimension. Reasonable assumptions on the shape of fragments concretize the power exponent, and vice versa possible destruction laws can be inferred on the basis of measured size distributions.Comment: 10 pages, 3 figure

A two-strain model of infectious disease spread with asymmetric temporary immunity periods and partial cross-immunity

We introduce a two-strain model with asymmetric temporary immunity periods and partial cross-immunity. We derive explicit conditions for competitive exclusion and coexistence of the strains depending on the strain-specific basic reproduction numbers, temporary immunity periods, and degree of cross-immunity. The results of our bifurcation analysis suggest that, even when two strains share similar basic reproduction numbers and other epidemiological parameters, a disparity in temporary immunity periods and partial or complete cross-immunity can provide a significant competitive advantage. To analyze the dynamics, we introduce a quasi-steady state reduced model which assumes the original strain remains at its endemic steady state. We completely analyze the resulting reduced planar hybrid switching system using linear stability analysis, planar phase-plane analysis, and the Bendixson-Dulac criterion. We validate both the full and reduced models with COVID-19 incidence data, focusing on the Delta (B.1.617.2), Omicron (B.1.1.529), and Kraken (XBB.1.5) variants. These numerical studies suggest that, while early novel strains of COVID-19 had a tendency toward dramatic takeovers and extinction of ancestral strains, more recent strains have the capacity for co-existence