Reply to Comment on Circular Dichroism in the Angle-Resolved Photoemission Spectrum of the High-Temperature Bi2Sr2CaCu2O8 Superconductor http://arxiv.org/abs/1004.1648

We conclude that arguments of Norman et al. in their Comment do not provide a significant basis for their claim that the geometric mechanism for explaining the observations reported by them is not viable. More generally, our study highlights the importance of assessing structural issues before invoking exotic mechanisms for explaining unusual spectroscopic observations, especially in complex materia

Effect of symmetry distortions on photoelectron selection rules and spectra of Bi_2Sr_2CaCu_2O_{8+ delta}

We derive photoelectron selection rules along the glide plane in orthorhombic Bi_2Sr_2CaCu_2O_{8+\delta} (Bi2212). These selection rules explain the reversed intensity behavior of the shadow and the main band of the material as a natural consequence of the variating representation of the final state as a function of k_\parallel. Our one-step simulations strongly support the structural origin of the shadow band but we also introduce a scenario for detecting antiferromagnetic signatures in low doping.Comment: AMS-LaTeX, 5 pages, 4 figure

Hybrids of the bHLH and bZIP Protein Motifs Display Different DNA-Binding Activities In Vivo vs. In Vitro

Minimalist hybrids comprising the DNA-binding domain of bHLH/PAS (basic-helix-loop-helix/Per-Arnt-Sim) protein Arnt fused to the leucine zipper (LZ) dimerization domain from bZIP (basic region-leucine zipper) protein C/EBP were designed to bind the E-box DNA site, CACGTG, targeted by bHLHZ (basic-helix-loop-helix-zipper) proteins Myc and Max, as well as the Arnt homodimer. The bHLHZ-like structure of ArntbHLH-C/EBP comprises the Arnt bHLH domain fused to the C/EBP LZ: i.e. swap of the 330 aa PAS domain for the 29 aa LZ. In the yeast one-hybrid assay (Y1H), transcriptional activation from the E-box was strong by ArntbHLH-C/EBP, and undetectable for the truncated ArntbHLH (PAS removed), as detected via readout from the HIS3 and lacZ reporters. In contrast, fluorescence anisotropy titrations showed affinities for the E-box with ArntbHLH-C/EBP and ArntbHLH comparable to other transcription factors (Kd 148.9 nM and 40.2 nM, respectively), but only under select conditions that maintained folded protein. Although in vivo yeast results and in vitro spectroscopic studies for ArntbHLH-C/EBP targeting the E-box correlate well, the same does not hold for ArntbHLH. As circular dichroism confirms that ArntbHLH-C/EBP is a much more strongly α-helical structure than ArntbHLH, we conclude that the nonfunctional ArntbHLH in the Y1H must be due to misfolding, leading to the false negative that this protein is incapable of targeting the E-box. Many experiments, including protein design and selections from large libraries, depend on protein domains remaining well-behaved in the nonnative experimental environment, especially small motifs like the bHLH (60–70 aa). Interestingly, a short helical LZ can serve as a folding- and/or solubility-enhancing tag, an important device given the focus of current research on exploration of vast networks of biomolecular interactions

Characterization of photonic crystal waveguides using Fabry-Perot resonances

A method for characterization of short photonic crystal waveguides is presented. The method utilizes mirror-enhanced Fabry–Perot resonances in the photonic crystal waveguide as well as in the insertion waveguides on either side of the photonic crystal waveguide. The method is applied to three-row defect (W3) photonic crystal waveguides fabricated into silicon-on-insulator wafers. The results are compared with those obtained with the conventional Fabry–Perot method

THE SOURCES AND DYNAMICS OF EMOTIONS IN ENTREPRENEURSHIP EDUCATION LEARNING PROCESS

The study investigates student experiences of entrepreneurship education and focuses on gaining a better understanding of the main sources of emotions as well as the role and dynamics of emotions in learning. Data was collected in three entrepreneurship education settings in Estonia, Finland and Namibia using in-depth interviews (N = 79) and was analysed using qualitative thematic analysis. As a result, three themes highlighting the main sources of emotions were identified: 1) new kind of learning environment, 2) collaborative learning, and 3) challenging tasks. The learning environment sub-categories were: 1a) uncertainty and confusion, 1b) theory versus practice and 1c) support from outside. The collaborative learning sub-categories consist of: 2a) teamwork, 2b) time pressure and 2c) individual differences. Challenging tasks had the sub-categories: 3a) overcoming knowledge and skills gaps, 3b) interacting with the outside world and 3c) leadership and managing people. In addition, dynamic patterns of emotions in the course of learning processes were identified