Temperature Effects on Development in \u3ci\u3eAphelinus Albipodus\u3c/i\u3e (Hymenoptera: Aphelinidae) From Two Geographic Regions

Aphelinus albipodus Hayat & Fatima was imported to the United States for classical biological control of the Russian wheat aphid, Diuraphis noxia (Mordvilko). Temperature effects on development of A. albipodus from two geographic regions (hereafter referred to as strains) were measured using the Russian wheat aphid as host. Temperature thresholds for egg to mummy, mummy to adult, and egg to adult development were 8.9,10.9, and 9.7°C for A. albipodus collected near Pingluo, China, and were and 8.5, 10.3, and 9.6°C for A. albipodus collected near Urumqi, China. The time required to develop from egg to adult did not differ among strains. However, when total immature development was partitioned into egg to mummy and mummy to adult, the time required for development through these two periods differed among strains. The Urumqi strain developed faster than the Pingluo strain from egg to mummy, while the Pingluo strain developed faster from mummy to adult. Degree-day requirements for egg to mummy development were 135 and 104 for the Pingluo and Urumqi strains, respectively. Corresponding requirements for mummy to adult development were 70 and 101 degree-days. The ability to vary immature development rate in response to climate or other factors could have adaptive significance because it would permit the parasitoid to exploit environments over a broad geographic range

Achieving "Massive MIMO" Spectral Efficiency with a Not-so-Large Number of Antennas

The main focus and contribution of this paper is a novel network-MIMO TDD architecture that achieves spectral efficiencies comparable with "Massive MIMO", with one order of magnitude fewer antennas per active user per cell. The proposed architecture is based on a family of network-MIMO schemes defined by small clusters of cooperating base stations, zero-forcing multiuser MIMO precoding with suitable inter-cluster interference constraints, uplink pilot signals reuse across cells, and frequency reuse. The key idea consists of partitioning the users population into geographically determined "bins", such that all users in the same bin are statistically equivalent, and use the optimal network-MIMO architecture in the family for each bin. A scheduler takes care of serving the different bins on the time-frequency slots, in order to maximize a desired network utility function that captures some desired notion of fairness. This results in a mixed-mode network-MIMO architecture, where different schemes, each of which is optimized for the served user bin, are multiplexed in time-frequency. In order to carry out the performance analysis and the optimization of the proposed architecture in a clean and computationally efficient way, we consider the large-system regime where the number of users, the number of antennas, and the channel coherence block length go to infinity with fixed ratios. The performance predicted by the large-system asymptotic analysis matches very well the finite-dimensional simulations. Overall, the system spectral efficiency obtained by the proposed architecture is similar to that achieved by "Massive MIMO", with a 10-fold reduction in the number of antennas at the base stations (roughly, from 500 to 50 antennas).Comment: Full version with appendice (proofs of theorems). A shortened version without appendice was submitted to IEEE Trans. on Wireless Commun. Appendix B was revised after submissio

Determinants of Demand for Participation in Wildlife Hunting: A County level Analysis

We developed an economic demand model of wildlife hunting and found that sociodemograpahic and ecological characteristics of county are its strong predictors. Result shows that the hunting is not popular among younger generation; and promoting hunting clubs and lease-hunting, recruiting young hunters could be effective policy considerations for retaining/promoting hunting.Wildlife hunting, License sales, Demand model, Resource /Energy Economics and Policy, Q21, Q26, L83,

Seismic Waveguide of Metamaterials

We have developed a new method of an earthquake-resistant design to support conventional aseismic designs using acoustic metamaterials. We suggest a simple and practical method to reduce the amplitude of a seismic wave exponentially. Our device is an attenuator of a seismic wave. Constructing a cylindrical shell-type waveguide that creates a stop-band for the seismic wave, we convert the wave into an evanescent wave for some frequency range without touching the building we want to protect.Comment: 4 pages, 4 figure

Forecasting Housing Prices under Different Submarket Assumptions

This research evaluated forecasting accuracy of hedonic price models based on a number of different submarket assumptions. Using home sale data for the City of Knoxville and vicinities merged with geographic information, we found that forecasting housing prices with submarkets defined using expert knowledge and by school district and combining information conveyed in different modeling strategies are more accurate and efficient than models that are spatially aggregated, or with submarkets defined by statistical clustering techniques. This finding provided useful implications for housing price prediction in an urban setting and surrounding areas in that forecasting models based on expert knowledge of market structure or public school quality and simple model combining techniques may outperform the models using more sophisticated statistical techniques.Clustering, Forecasting, Hedonic price, Housing Submarket, Demand and Price Analysis, C53, R21,

Dynamical mean-field theory of Hubbard-Holstein model at half-filling: Zero temperature metal-insulator and insulator-insulator transitions

We study the Hubbard-Holstein model, which includes both the electron-electron and electron-phonon interactions characterized by $U$ and $g$, respectively, employing the dynamical mean-field theory combined with Wilson's numerical renormalization group technique. A zero temperature phase diagram of metal-insulator and insulator-insulator transitions at half-filling is mapped out which exhibits the interplay between $U$ and $g$. As $U$ ($g$) is increased, a metal to Mott-Hubbard insulator (bipolaron insulator) transition occurs, and the two insulating states are distinct and can not be adiabatically connected. The nature of and transitions between the three states are discussed.Comment: 5 pages, 4 figures. Submitted to Physical Review Letter