Superlinear Increase of Photocurrent due to Stimulated Scattering into a Polariton Condensate

We show that when a monopolar current is passed through an n-i-n structure, superlinear photocurrent response occurs when there is a polariton condensate. This is in sharp contrast to the previously observed behavior for a standard semiconductor laser. Theoretical modeling shows that this is due to a stimulated exciton-exciton scattering process in which one exciton relaxes into the condensate, while another one dissociates into an electron-hole pair.Comment: 17 pages with 10 figure

Development of a community of inquiry in online and blended learning contexts

AbstractThis paper discusses findings of a mixed method research project with the goal to study the development of a community of inquiry in online and blended learning environments. A graduate course delivered online and blended format was the focus of the study. Data was gathered from the Community of Inquiry Survey and transcript analysis of online discussions to explore the developmental differences on each presence (social, teaching and cognitive). The results showed: significant differences on social and cognitive presence between two course formats and higher perceptions of the presences in blended course

Calculated and Observed Settlements of Multistory Building Founded on Loess

ln the Paper are presented the results of laboratory and field tests which were carried out on loess soil in Belgrade In order to determine the type of the foundation for the 13-storey building a preliminary investigation was made. In this phase of investigation exploratory borings and sampling were performed in a standard way. On the basis of the available laboratory and field test results it was concluded that the soil was made of macro porous land loess 14-20 m in thickness. lt was found that the loess on this location had the dry density varying between the limits γd = 15.5 - 15.8 kN/m3. Considering that the subsoil has high values of dry density, the designer adopted the shallow foundations. At the end of the period of three years one part of the building settled considerably and the differential settlements reached very high values. Due to the significant values of the angular distortion the building was seriously damaged. By additional investigation the undisturbed loess samples were cut from blocks and the laboratory results have shown much lower values of the deformation parameters than those obtained in the preliminary investigations. Using the deformation parameters and the coefficients of subsidence for the undisturbed samples cut from blocks, a very good agreement between the calculated and observed settlement was obtained

Low Doses of the Carcinogen Furan Alter Cell Cycle and Apoptosis Gene Expression in Rat Liver Independent of DNA Methylation

BACKGROUND: Evidence of potent rodent carcinogenicity via an unclear mechanism suggests that furan in various foods [leading to an intake of up to 3.5 mu g/kg body weight (bw)/day] may present a potential risk to human health

Smart Timing for Smart Products? Complementor Multihoming in Nascent Platform Markets

Complementor multihoming is becoming pervasive in platform-mediated markets populated by multiple platforms. In a study of the nascent “smart home” industry, we use a novel dataset to examine complementor strategies regarding timing of entry and timing of multihoming, with their corresponding performance implications. We find that early entrants to a platform market multihome faster than later entrants. While early entrants achieve lower performance than later entrants, this negative performance effect is mitigated for complementors that multihome fast. This implies that multihoming is an effective hedging strategy for early entrants in multi-platform markets characterized by high uncertainty. Also, multihoming scope (number of platforms a complementor joins) is associated with higher complementor performance and shorter time to the next platform adoption

Observation of nonequilibrium motion and equilibration in polariton rings

We present a study of the macroscopic dynamics of a polariton condensate formed by nonresonant optical excitation in a quasi-one-dimensional ring-shaped microcavity. The presence of a gradient in the cavity photon energy creates a macroscopic trap for the polaritons in which a coherent condensate is formed which evolves into a single-mode condensate at late times. With time- and energy-resolved imaging we show the role of interactions in the motion of the condensate as it undergoes equilibration in the ring. These experiments also give a direct measurement of the polariton-polariton interaction strength above the condensation threshold. Our observations are compared to the open-dissipative one-dimensional Gross-Pitaevskii equation which shows excellent qualitative agreement