A Cross-National Comparison of Consumers\u27 Attitudes Toward Direct Marketing and Purchase Intention

Existing research indicates that attitudes toward the three elements of direct marketing (the source, mode, and response channel) influence consumers\u27 intentions to purchase directly marketed products. While research investigating attitudes and consumers\u27 response has been conducted in the U.S., there has been no research to date which examines attitude structures and purchase intentions towards direct marketing in a multi-country setting, in spite of the standardized global efforts of direct marketeers. This study presents findings on attitude structures regarding direct marketing for three affluent open markets, the U.S., Singapore, and the Netherlands and empirically investigates the relationships between these consumers\u27 attitudes toward the three elements of direct marketing and purchase intentions

Electron Scattering in AlGaN/GaN Structures

We present data on mobility lifetime, $\tau_t$, quantum lifetime, $\tau_q$, and cyclotron resonance lifetime, $\tau_{CR}$, of a sequence of high-mobility two-dimensional electron gases in the AlGaN/GaN system, covering a density range of $\sim1-4.5\times10^{12}$cm$^{-2}$. We observe a large discrepancy between $\tau_q$ and $\tau_{CR}$ ($\tau_q\sim\tau_{CR}$/6) and explain it as the result of density fluctuations of only a few percent. Therefore, only $\tau_{CR}$ --and not $\tau_q$ -- is a reliable measure of the time between electron scattering events in these specimens. The ratio $\tau_t / \tau_{CR}$ increases with increasing density in this series of samples, but scattering over this density range remains predominantly in the large-angle scattering regime

Modeling and Analysis of Content Caching in Wireless Small Cell Networks

Network densification with small cell base stations is a promising solution to satisfy future data traffic demands. However, increasing small cell base station density alone does not ensure better users quality-of-experience and incurs high operational expenditures. Therefore, content caching on different network elements has been proposed as a mean of offloading he backhaul by caching strategic contents at the network edge, thereby reducing latency. In this paper, we investigate cache-enabled small cells in which we model and characterize the outage probability, defined as the probability of not satisfying users requests over a given coverage area. We analytically derive a closed form expression of the outage probability as a function of signal-to-interference ratio, cache size, small cell base station density and threshold distance. By assuming the distribution of base stations as a Poisson point process, we derive the probability of finding a specific content within a threshold distance and the optimal small cell base station density that achieves a given target cache hit probability. Furthermore, simulation results are performed to validate the analytical model.Comment: accepted for publication, IEEE ISWCS 201

Non-parabolicity of the conduction band of wurtzite GaN

Using cyclotron resonance, we measure the effective mass, $m$*, of electrons in AlGaN/GaN heterostructures with densities, $n_{2D}\sim 1-6\times10^{12}$cm$^{-2}$. From our extensive data, we extrapolate a band edge mass of $(0.208\pm0.002) m_e$. By comparing our $m$* data with the results of a multi-band \textbf{k.p} calculation we infer that the effect of remote bands is essential in explaining the observed conduction band non-parabolicity (NP). Our calculation of polaron mass corrections -- including finite width and screening - suggests those to be negligible. It implies that the behavior of $m*(n_{2D})$ can be understood solely in terms of NP. Finally, using our NP and polaron corrections, we are able to reduce the large scatter in the published band edge mass values

The phytosociological analysis of saline area of Tehsil Ferozewala, District Sheikhupura (Punjab), Pakistan

This study is a broad ecological survey, and classification of the vegetation of Agro Farm plantations of a Tehsil Ferozewala (District Sheikhupura) Punjab, Pakistan. The vegetation survey description and classification was according to Zurich-Montpellier School of thought is based on over 300 Relevé Method. In all twelve associations i.e. Suaedetum fruticosae, Kochietum indicum Diplachnetum fuscae, Desmostochyetum bipinnatae, maurorae, Polypogaetum monspeliensae, Erythraeo-Polypogaetum monspeliensae, Veteviarietum cylindrieae, Scirpetum maritimae and Typhetum angustitae are recognized and each association is further sub-divided into sub-associations and classified into its respective class, order and alliances according to central European Phyto-sociological methods. Several relationships of the plant community types have been worked out during this study. The soil characteristics of each vegetation type are discussed in relation to soil texture; pH, Conductivity, Carbonates, Bicarbonates, Chlorides and Sulphate as well as ecological affinities of each association are also described. By reintegrating these trees and shrubs back into agriculture landscape to reverse salinity such as Atriplex amnicla, Tamarix aphylla, Phoenix dactilifera, Prosopis spp. Susbenia bispinasa, Sesbenia sesbena, Casorina, Grewia asiatie, Psidium guava etc. The incorporation of these plants (grasses, shrubs and trees) into agriculture land system of the Punjab has potential to increase crop, fiber, wood and animal production and degradation of land will also be halted.Key words: Phyto-sociological, agroforestry, relev’es, plant associations, characteristic species, differential species, companion species

Covid-19 Re-infection vs Prolonged Viral Shedding

  Since December 2019, COVID 19 pandemic has devastated communities across the world. As number of patients recovered from COVID 19 continue to rise, question of acquired immunity versus chances of re-infection becomes critical to understand the future spread of infection. Here, we present a case of a patient previously recovered from COVID-19, develops new symptoms concerning for possible re-infection with positive reverse transcriptase-polymerase chain reaction (RT-PCR) after few months of initial infection. &nbsp

Disorder mediated splitting of the cyclotron resonance in two-dimensional electron systems

We perform a direct study of the magnitude of the anomalous splitting in the cyclotron resonance (CR) of a two-dimensional electron system (2DES) as a function of sample disorder. In a series of AlGaAs/GaAs quantum wells, identical except for a range of carbon doping in the well, we find the CR splitting to vanish at high sample mobilities but to increase dramatically with increasing impurity density and electron scattering rates. This observation lends strong support to the conjecture that the non-zero wavevector, roton-like minimum in the dispersion of 2D magnetoplasmons comes into resonance with the CR, with the two modes being coupled via disorder.Comment: accepted to PRB Rapid Com

Acoustic phonon scattering in a low density, high mobility AlGaN/GaN field effect transistor

We report on the temperature dependence of the mobility, $\mu$, of the two-dimensional electron gas in a variable density AlGaN/GaN field effect transistor, with carrier densities ranging from 0.4$\times10^{12}$ cm$^{-2}$ to 3.0$\times10^{12}$ cm$^{-2}$ and a peak mobility of 80,000 cm$^{2}$/Vs. Between 20 K and 50 K we observe a linear dependence $\mu_{ac}^{-1} = \alpha$T indicating that acoustic phonon scattering dominates the temperature dependence of the mobility, with $\alpha$ being a monotonically increasing function of decreasing 2D electron density. This behavior is contrary to predictions of scattering in a degenerate electron gas, but consistent with calculations which account for thermal broadening and the temperature dependence of the electron screening. Our data imply a deformation potential D = 12-15 eV.Comment: 3 pages, 2 figures, RevTeX. Submitted to Appl Phys Let