GaN and InN nanowires grown by MBE: a comparison

Morphological, optical and transport properties of GaN and InN nanowires grown by molecular beam epitaxy (MBE) have been studied. The differences between the two materials in respect to growth parameters and optimization procedure was stressed. The nanowires crystalline quality has been investigated by means of their optical properties. A comparison of the transport characteristics was given. For each material a band schema was shown, which takes into account transport and optical features and is based on Fermi level pinning at the surface.Comment: 5 pages, 5 figure

Musicking with an interactive musical system: The effects of task motivation and user interface mode on non-musicians' creative engagement

Creative engagement with novel musical interfaces can be rewarding for non-musicians. However, designing novel musical interfaces for non-musicians can be challenging because they lack conceptual and technical musical skills. In this paper we explore the effects of task motivation (experiential goal vs utilitarian goal) and user interface mode (whether the content is editable, and whether content can be replayed), on non-musicians’ creative engagement with novel musical interfaces. We show through an empirical study of twenty-four parti- cipants that an experiential exploratory goal encourages users’ creative engagement compared to a utilitarian creative goal. We found that being able to replay records is less important when participants have an experiential exploratory goal than when they have a utilitarian creative goal. Results also indicate that allowing people to replay their musical ideas increased some aspects of their creative engagement which was further increased when they were able to edit their creations. We also found that creative engagement increased when the in- terface supported users in planning ahead. A descriptive model of non-musician’s creative engagement with musical interfaces is proposed including three modes of musicking. An optimal trajectory of creative engagement through these modes is suggested and a description of inferred motivations, output, status and activities during creative processes is discussed. Design implications are proposed for supporting novices’ creative engagement taking into consideration their motivation and skills, and supporting insight and real-time activity

The MeerKAT Galaxy Cluster Legacy Survey: I. Survey overview and highlights

Please abstract in the article.The South African Radio Astronomy Observatory (SARAO), the National Research Foundation (NRF), the National Radio Astronomy Observatory, US National Science Foundation, the South African Research Chairs Initiative of the DSI/NRF, the SARAO HCD programme, the South African Research Chairs Initiative of the Department of Science and Innovation.http://www.aanda.orghj2022Physic

Hanging tough:Post-PhD researchers dealing with career uncertainty

This study examines the impact of career uncertainty on post-PhD researchers? experiences. Drawing on an identity-trajectory approach and a qualitative design, we analysed experiences of post-PhDs from the UK and Switzerland. Our findings show that in the course of their work experiences, career uncertainty takes two different forms: intellectual uncertainty and occupational uncertainty. On a daily basis, both forms strongly impact the participants? work and personal lives and can limit their ability to plan for the future, restrict their developing research expertise and networks and induce tension in trying to reconcile work and personal lives. While often struggling with a blurred institutional status, participants ?hang tough? despite their uncertain situation, notably by clinging to the academic researcher identity. Contributing to the previous work on the increasing casualisation of post-PhD positions and the resulting challenges, our study offers new insights into how different aspects of career uncertainty influence post-PhDs? work and identity

The 'prismane' protein resolved: X-ray structure at 1.7A and multiple spectroscopy of two novel 4Fe clusters.

The three-dimensional structure of the native "putative prismane" protein from Desulfovibrio vulgaris (Hildenborough) has been solved by X-ray crystallography to a resolution of 1.72 Å. The molecule does not contain a [6Fe-6S] prismane cluster, but rather two 4Fe clusters some 12 Å apart and situated close to the interfaces formed by the three domains of the protein. Cluster 1 is a conventional [4Fe-4S] cubane bound, however, near the N-terminus by an unusual, sequential arrangement of four cysteine residues (Cys 3, 6, 15, 21). Cluster 2 is a novel 4Fe structure with two 72-sulfido bridges, two 72-oxo bridges, and a partially occupied, unidentified 72 bridge X. The protein ligands of cluster 2 are widely scattered through the second half of the sequence and include three cysteine residues (Cys 312, 434, 459), one persulfido-cysteine (Cys 406), two glutamates (Glu 268, 494), and one histidine (His 244). With this unusual mixture of bridging and external type of ligands, cluster 2 is named the "hybrid" cluster, and its asymmetric, open structure suggests that it could be the site of a catalytic activity. X-ray absorption spectroscopy at the Fe K-edge is readily interpretable in terms of the crystallographic model when allowance is made for volume contraction at 10 K; no Fe??Fe distances beyond 3.1 Å could be identified. EPR, Mössbauer and MCD spectroscopy have been used to define the oxidation states and the magnetism of the clusters in relation to the crystallographic structure. Reduced cluster 1 is a [4Fe-4S]1 cubane with S = 3/2; it is the first biological example of a "spin-admixed" iron-sulfur cluster. The hybrid cluster 2 has four oxidation states from (formally) all FeIII to three FeII plus one FeIII. The four iron ions are exchange coupled resulting in the system spins S = 0, 9/2, 0 (and 4), 1/2, respectively, for the four redox states. Resonance Raman spectroscopy suggests that the bridging ligand X which could not be identified unambiguously in the crystal structure is a solvent-exchangeable oxygen