Can Impurity Effects Help to Identify the Symmetry of the Order Parameter of the Cuprates?

The effects of non-magnetic impurities on the properties of superconductors with order parameters (OP) of different symmetry are discussed. In particular, we contrast the case of a d_{x^2 - y^2} with various forms of an anisotropic s-wave (ASW) gap. The biggest qualitative difference occurs if the phase of the s-wave OP does not change sign.Comment: 2pages, uuencoded Postscript, to appear in the Proceedings of the M^2-HTSC IV conferenc

Terahertz Near-field Investigation of a Plasmonic GaAs Superlens

This work presents the first demonstration of a semiconductor based plasmonic near-field superlens, utilizing highly doped GaAs to generate infrared optical images with a spatial resolution beyond the difraction limit. Being easily transferable to other semiconductor materials, the concept described in this thesis can be exploited to realize spectrally adjustable superlenses in a wide spectral range. The idea of superlensing has been introduced theoretically in 2000, followed by numerous publications including experimental studies. The effect initiated great interest in optics, since in contrast to difraction limited conventional optical microscopy it enables subwavelength resolved imaging by reconstructing the evanescent waves emerging from an object. With techniques like scanning near-field optical microscopy (SNOM) and stimulated emission depletion (STED) being already successfully established to overcome the conventional restrictions, the concept of superlensing provides a novel, different route towards high resolution. Superlensing is a resonant phenomenon, relying either on the excitation of surface plasmons in metallic systems or on phonon resonances in dielectric structures. In this respect a superlens based on doped semiconductor benefits from the potential to be controlled in its operational wavelength by shifting the plasma frequency through adjustment of the free carrier concentration. For a proof of principle demonstration, we investigate a superlens consisting of a highly n-doped GaAs layer (n = 4 x 10^18 cm-3) sandwiched between two intrinsic layers. Recording near-field images of subwavelength sized gold stripes through the trilayer structure by means of SNOM in combination with a free-electron laser, we observe both enhanced signal and improved spatial resolution at radiation wavelengths close to l = 22 µm, which is in excellent agreement with simulations based on the Drude-Lorentz model of free electrons. Here, comparative investigations of a purely intrinsic reference sample confirm that the effect is mediated by the charge carriers within the doped layer. Furthermore, slightly differently doped samples provide indications for the expected spectral shift of the resonance. According to our calculations, the wavelength range to be exploited by n-GaAs based superlenses reaches far into the terahertz region, whereas other semiconductor materials are required to explore the near infrared

The Experiences of Dentists and Dental Hygienists as They Transition to Teaching as Clinical Instructors: A Transcendental Phenomenology

The purpose of this transcendental phenomenology was to explore the experiences of dentists and dental hygienists who transitioned from clinical practice to the role of clinical instructor at Southern University. The theory of andragogy was used to guide this study because it provided a framework for training clinical instructors as adult learners. This study focused on the central research question, What are the experiences of dentists and dental hygienists who have transitioned from clinical practice to the role of clinical instructors? A transcendental phenomenological study approach was used to provide a deeper understanding of participants\u27 experiences and their thought processes as they transitioned from clinical practitioners to their roles as clinical instructors. Purposeful sampling was used to recruit dentists and dental hygienists who served as clinical instructors in a dental hygiene program at a midwestern public university. Data collection was triangulated using individual interviews, photograph journals, and a virtual focus group. Data analysis was conducted using epoché, phenomenological reduction, imaginative variance, and synthesis of the structural and textural descriptions gathered during data collection. The researcher uncovered five themes from the data collection: life responsibilities, challenges faced, training received, training needed, and training delivery preferences. These themes helped to create an understanding of the phenomena of transitioning from clinical practitioner to clinical instructor as the participants experienced it. The study\u27s findings demonstrated the need to train dentists and dental hygienists to become clinical instructors. Keywords: dental hygiene, clinical instructor, adult learning theory, professional developmen

Affect Infusion and Detection through Faces in Computer-mediated Knowledge-sharing Decisions

Faces are important in both human communication and computer-mediated communication. In this study, I analyze the influence of emotional expressions in faces on knowledge-sharing decisions in a computer-mediated environment. I suggest that faces can be used for affect infusion and affect detection, which increases the effectiveness of knowledge-management systems. Using the affect infusion model, I discuss why emotions can be expected to influence knowledge-sharing decisions. Using the two-step primitive emotional contagion framework, I found that emotional facial expression attached to a knowledge-sharing request influenced knowledge-sharing decisions. This influence was mediated by the decision maker’s emotional valence in the facial expression tracked by Face Reader technology and held for females but not males. I discuss implications for designers of emotionally intelligent information systems and research

CONTRACT FRAME AND PARTICIPATION: MITIGATING DISADVANTAGES OF PENALTY CONTRACTS

Contracting is an important aspect of IT governance and control. This aspect involves the manner in which goals are set, their achievements rewarded and penalized. In the context of service level agreements it has been shown that contracts that involve penalties have positive effects on individuals’ effort and negative effects on individuals’ attitude such as fairness perception. The negative effects of penalty clauses are a likely reason why they are rarely found in contracting with individuals. Our study was motivated by the question whether negative effects of penalty contracts can be mitigated. In an experiment we found that controllee participation can mitigate such negative effects. This implies that controllee participation is even more important in the face of penalty contracts in order to maintain high fairness perception levels

Contextual Factors Influencing Perceived Importance and Trade-offs of Information Quality

With the ever-increasing importance of information quality (IQ), research focuses mainly on two approaches, criteria and assessment. Researchers developed a number of frameworks, criteria lists, and approaches for assessing and measuring IQ. Several studies confirm that IQ is a multi-criteria concept, and its evaluation should consider different aspects. However, research and discussions with practitioners indicate that assessing and managing IQ in organizations remains challenging. Despite the subjective character of quality, foremost frameworks and assessment methodologies do not often consider the context in which the assessment is performed. Trade-offs between criteria are often not considered in most frameworks despite strong evidence in the literature that suggests trade-off relations exist. Underlying a user-centric view, this study analyses the importance of selected contextual factors and their impact on IQ criteria. Empirical data are gathered using a questionnaire approach. Results suggest significant context impacts and show that the perceived importance of information quality criteria changed over the last decade. Information and communication technology, available resources, the user role, the department, and the type of information systems influence respondents’ perception of IQ. These factors are incorporated in a context-oriented IQ research framework