Role of multi-level states on quantum-dot emission in photonic-crystal cavities

Semiconductor quantum dots embedded in photonic-crystal nanostructures have been the subject of intense study. In this context, quantum dots are often considered to be simple two-level emitters, i.e., the complexities arising from the internal finestructure are neglected. We show that due to the intricate spatial variations of the electric field polarization found in photonic crystal, the two orthogonal finestructure states of quantum dots in general both couple significantly to a cavity mode, implying that the two-level description is not sufficient. As a consequence the emission dynamics and spectra, which are often recorded in experiments, are modified both in the weak- and strong-coupling regimes. The proposed effects are found to be significant for system parameters of current state-of-the-art photonic-crystal cavities

What Happens in Therapy? Adolescents' Expectations and Perceptions of Psychotherapy

An empirically based measure of adolescent pre-treatment expectations and perceptions of psychotherapy is provided with supporting literature from service-use models, common factors research, evidence-based practice principles, and expectancies. The development of the Psychotherapy Expectations and Perceptions Inventory (PEPI) is described with initial psychometric properties reported based on data from 546 adolescents (age 14-18). Results indicate adequate internal consistency and a 3 factor structure measuring negative expectancies, process/outcome expectancies, and expectancies for a positive therapeutic relationship. Boys reported greater negative expectancies, but also greater expectancies for a positive therapeutic relationship. Girls reported greater therapy process/outcome expectancies. Level of contact with mental illness was not a significant predictor for any factors. An item response report is provided. Clinical and educational implications are discussed. Clinicians might be advised assess adolescent expectancies in treatment to facilitate greater rapport and engagement in the therapeutic process in order to foster more therapeutic change

Strong, Bold, and Kind: Self-Control and Cooperation in Social Dilemmas

We develop a model relating self-control, risk preferences and conflict identification to cooperation patterns in social dilemmas. We subject our model to data from an experimental public goods game and a risk experiment, and we measure conflict identification and self-control. As predicted, we find a robust association between self-control and higher levels of cooperation, and the association is weaker for more risk-averse individuals. Free riders differ from other contributor types only in their tendency not to have identified a self-control conflict in the first place. Our model accounts for the data at least as well as do other models

Single Crystal Growth of FeGa3 and FeGa3−xGex from High‐Temperature Solution Using the Czochralski Method

Single crystal growth and characterization of the binary semiconducting compound FeGa3 and its Ge‐substitute FeGa3–xGex are reported. Whereas there have been several investigations on the thermoelectric properties based on small samples grown by the flux method, this study is the first approach using the Czochralski growth technique from well‐oriented single‐crystalline seeds. Problems and solutions of the growth of cm3‐size single crystals are discussed in detail. Ge segregation in FeGa3–xGex is described by a segregation coefficient lower than unity which leads to an axially increasing Ge content along the pulling direction. Consequences with respect to lattice parameter changes and thermoanalytic measurements are reported

SE-ENRICHMENT OF CARROT AND ONION VIA FOLIAR APPLICATION

The aim of this work was to study the selenium accumulation in carrot and onion plants using foliar application by sodium selenite and sodium selenate. Furthermore, we aimed at identifying the Se species biosynthesised by onion and carrot plants. The results were used to prepare for production of 77Se enriched plants for an ongoing human absorption study

Spin dynamics of FeGa3−x_{3-x}Gex_x studied by Electron Spin Resonance

The intermetallic semiconductor FeGa$_{3}$ acquires itinerant ferromagnetism upon electron doping by a partial replacement of Ga with Ge. We studied the electron spin resonance (ESR) of high-quality single crystals of FeGa$_{3-x}$Ge$_x$ for $x$ from 0 up to 0.162 where ferromagnetic order is observed. For $x = 0$ we observed a well-defined ESR signal, indicating the presence of pre-formed magnetic moments in the semiconducting phase. Upon Ge doping the occurrence of itinerant magnetism clearly affects the ESR properties below $\approx 40$~K whereas at higher temperatures an ESR signal as seen in FeGa$_{3}$ prevails independent on the Ge-content. The present results show that the ESR of FeGa$_{3-x}$Ge$_x$ is an appropriate and direct tool to investigate the evolution of 3d-based itinerant magnetism.Comment: 12 pages, 7 figure