1,053 research outputs found
Hybridization of sub-gap states in one-dimensional superconductor/semiconductor Coulomb islands
We present measurements of one-dimensional superconductor-semiconductor
Coulomb islands, fabricated by gate confinement of a two-dimensional InAs
heterostructure with an epitaxial Al layer. When tuned via electrostatic side
gates to regimes without sub-gap states, Coulomb blockade reveals Cooper-pair
mediated transport. When sub-gap states are present, Coulomb peak positions and
heights oscillate in a correlated way with magnetic field and gate voltage, as
predicted theoretically, with (anti) crossings in (parallel) transverse
magnetic field indicating Rashba-type spin-orbit coupling. Overall results are
consistent with a picture of overlapping Majorana zero modes in finite wires
SCHOOLING BEHAVIOUR OF SARDINE SARDINOPS SAGAX IN FALSE BAY, SOUTH AFRICA
The schooling behaviour of sardine Sardinops sagax in False Bay on the south coast of South Africa was studied in October 1995 using high-resolution sonar and a hull-mounted, echo-integration unit. School formation and disintegration were studied, and school shape, packing density, swimming behaviour and inter- and intra-school event rates were quantified. Mean fish density was 29.5 fish m-3 (SD 46 fish m-3), but it varied between schools by a factor of about 100 (from 2 to 233 fish m-3). Tracked schools moved at average speeds of 0.67–1.59 m s-3. Schools changed shape on average every 2.08 minutes, and underwent either splits or merges with other schools on average every 5 minutes. Relationships between the geometric dimensions and biomass of the schools were established.Afr. J. mar. Sci. 25: 185–19
Ultralong Copper Phthalocyanine Nanowires with New Crystal Structure and Broad Optical Absorption
The development of molecular nanostructures plays a major role in emerging
organic electronic applications, as it leads to improved performance and is
compatible with our increasing need for miniaturisation. In particular,
nanowires have been obtained from solution or vapour phase and have displayed
high conductivity, or large interfacial areas in solar cells. In all cases
however, the crystal structure remains as in films or bulk, and the
exploitation of wires requires extensive post-growth manipulation as their
orientations are random. Here we report copper phthalocyanine (CuPc) nanowires
with diameters of 10-100 nm, high directionality and unprecedented aspect
ratios. We demonstrate that they adopt a new crystal phase, designated
eta-CuPc, where the molecules stack along the long axis. The resulting high
electronic overlap along the centimetre length stacks achieved in our wires
mediates antiferromagnetic couplings and broadens the optical absorption
spectrum. The ability to fabricate ultralong, flexible metal phthalocyanine
nanowires opens new possibilities for applications of these simple molecules
Morphology and spectral properties of the DART impact ejecta with VLT/MUSE
Context. On September 26, 2022, the NASA DART mission impacted the asteroid Dimorphos, the smaller component of the Didymos binary asteroid system. This provided a unique opportunity to observe, in real time, the evolution of the ejecta cloud produced by the impact and the formation of a tail.
Aims. We present observations performed with the MUSE instrument at the Very Large Telescope to characterise the morphology, spectral properties, and evolution of the ejecta. The Didymos system was observed with MUSE on 11 nights from just before impact to almost one month post-impact, using both wide-field observations without adaptive optics and narrow-field observations with adaptive optics.
Methods. We produced white light images that were used to study the morphology of the ejecta at different spatial scales. The spectral information was used to search for gas emission from either exposed ice or propellant, and to study the spatial and temporal variation of the ejecta dust reflectance through reflectance maps.
Results. We searched for, but did not detect, emission from [OI], Xe, NH2, and H2O+ in a 1′×1′ field of view in our observations starting almost 4h after impact. We detected a number of morphological features, including a short-lived ejecta cloud visible on September 27 towards the east, spirals, clumps, and a tail that started forming only a few hours after impact. The analysis of the reflectance maps showed that the initial ejecta was bluer than the system before impact, while the tail and spirals were redder than the initial ejecta, consistent with them being made of larger particles. Over the few weeks following impact, the tail became redder. No significant colour differences could be seen between the clumps and the initial ejecta
Conceptualizing the adventure-sports coach
As a comparatively recent development, the adventure-sports coach struggles for a clear and distinct identity. The generic term ‘instructor’ no longer characterizes the role and function of this subgroup of outdoor professionals. Indeed, although the fields of adventure/outdoor education and leadership are comparatively well researched, the arrival of this ‘new kid on the block’ appears to challenge both the adventure-sports old guard and traditional views of sports coaching. In an attempt to offer clarity and stimulate debate, this paper attempts to conceptualize the adventure-sports coach in the context of the existing roles in the field and current motivations for activity in the outdoors. We identify issues that are specific to the adventure-sports coach while also recognizing those skills and competencies shared with other professionals, both in the adventure sports profession and traditional sports coaching fields. Based on this review, we offer a conceptual model which may be used to focus debate, stimulate research and, at a possible later stage, to underpin accreditation, training and professional development
Creativity mindset as the organizational capability: the role of creativity-relevant processes, domain-relevant skills and intrinsic task motivation
Purpose The objective of this study is to examine the structural relationship between creativity-relevant processes, domain-relevant skills, intrinsic task motivation, creativity and the moderating effect of social environment (sufficient resources, workgroup support, realistic work pressure and lack of organizational impediments). Design/methodology/approach A total of 289 valid questionnaires were collected from engineering students in Malaysian universities to test the measurement as well as the structural model using partial least squares (PLS) path modelling. Findings While the statistical results support the structural relationships (direct effects), the social environment shows the insignificant moderating effect (except creativity relevant process to sufficient resource to creativity). Work-group support, sufficient resources and lack of organizational impediments, as the three factors of the social environment, will not have any effect on creativity of upcoming engineers. This study reveals that while a high level of domain-relevant skills, intrinsic task motivation and creativity-relevant processes influence creativity among the sample of engineering students, social environment acts as an insignificant moderator to the creativity perception. Originality/value While businesses in the emerging markets mostly neglect the concept of developing creative mindsets among engineering students, in the competitive world of business that is extremely fast-paced, being creative within a business setting will act as a paramount criterion to differentiate. Practical and theoretical implications are discussed
The Angular Correlation Function of K=19.5 Galaxies and the Detection of a Cluster at z=0.775
On five K-band Omega camera images, covering a total of 162.2 sq. arcmin to
K=19.5, we investigate (i) the clustering environment of 5 radio galaxies at
0.7<z<0.8 and (ii) the galaxy angular correlation function. We detect a cluster
of estimated Abell richness class 1 or 2, centred on the radio galaxy 5C6.75 at
z=0.775. Of the other radio galaxies, two appear to be in less rich groups or
structures, and two in field environments. The mean clustering environment of
all 5 is similar to that of radio galaxies at more moderate redshifts of
0.35<z<0.55. The angular correlation function of the galaxies, at limits
K=18.5--20.0, is most consistent with a luminosity evolution model in which
E/S0 galaxies are much more clustered than spirals (r_0=8.4 compared to 4.2 1/h
Mpc) and clustering is approximately stable (epsilon=0), although the
clustering may exceed the stable model at the highest (z>1.5) redshifts. We
also find a significant excess of 1.5--5.0 arcsec separation pairs of galaxies
compared to the expectation from the inward extrapolation of omega(theta). To
K=19.5, we estimate that 11.0\pm 3.4 per cent of galaxies are in close pairs in
excess of omega(theta). This can be explained if the local rate of galaxy
mergers and interactions increases with redshift as with
.Comment: 14 pages, latex, 8 figures, submitted to MNRA
The solution structure of the human IgG2 subclass is distinct from those for human IgG1 and IgG4 providing an explanation for their discrete functions
Human IgG2 antibody displays distinct therapeutically-useful properties compared with the IgG1, IgG3 and IgG4 antibody subclasses. IgG2 is the second most abundant IgG subclass, being able to bind human FcγRII/FcγRIII, but not to FcγRI or complement C1q. Structural information on IgG2 is limited by the absence of a full-length crystal structure for this. To this end, we determined the solution structure of human myeloma IgG2 by atomistic X-ray and neutron scattering modelling. Analytical ultracentrifugation disclosed that IgG2 is monomeric with a sedimentation coefficient s020,w of 7.2 S. IgG2 dimer formation was ≤ 5% and independent of the buffer conditions. Small-angle X-ray scattering in a range of NaCl concentrations and in light and heavy water revealed that the X-ray radius of gyration Rg is 5.2-5.4 nm, after allowing for radiation damage at higher concentrations, and that the neutron Rg value of 5.0 nm remained unchanged in all conditions. The X-ray and neutron distance distribution curves P(r) revealed two peaks, M1 and M2, that were unchanged in different buffers. The creation of ˃123,000 physically-realistic atomistic models by Monte Carlo simulations for joint X-ray and neutron-scattering curve fits, constrained by the requirement of correct disulfide bridges in the hinge, resulted in the determination of symmetric Y-shaped IgG2 structures. These molecular structures were distinct from those for asymmetric IgG1 and asymmetric and symmetric IgG4, and were attributable to the four hinge disulfides. Our IgG2 structures rationalize the existence of the human IgG1, IgG2, and IgG4 subclasses, and explain the receptor binding functions of IgG2
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