Maximising Social Interactions and Effectiveness within Distance Learning Courses: Cases from Construction

Advanced Internet technologies have revolutionised the delivery of distance learning education. As a result, the physical proximity between learners and the learning providers has become less important. However, whilst the pervasiveness of these technological developments has reached unprecedented levels, critics argue that the student learning experience is still not as effective as conventional face-to-face delivery. In this regard, surveys of distance learning courses reveal that there is often a lack of social interaction attributed to this method of delivery, which tends to leave learners feeling isolated due to a lack of engagement, direction, guidance and support by the tutor. This paper defines and conceptualises this phenomenon by investigating the extent to which distance-learning programmes provide the social interactions of an equivalent traditional classroom setting. In this respect, two distance learning case studies were investigated, covering the UK and Slovenian markets respectively. Research findings identified that delivery success is strongly dependent on the particular context to which the specific distance learning course is designed, structured and augmented. It is therefore recommended that designers of distance learning courses should balance the tensions and nuances associated with commercial viability and pedagogic effectiveness

Spinor Bose-Einstein Condensates with Many Vortices

Vortex-lattice structures of antiferromagnetic spinor Bose-Einstein condensates with hyperfine spin F=1 are investigated theoretically based on the Ginzburg-Pitaevskii equations near $T_{c}$. The Abrikosov lattice with clear core regions are found {\em never stable} at any rotation drive $\Omega$. Instead, each component $\Psi_{i}$ $(i=0,\pm 1)$ prefers to shift the core locations from the others to realize almost uniform order-parameter amplitude with complicated magnetic-moment configurations. This system is characterized by many competing metastable structures so that quite a variety of vortices may be realized with a small change in external parameters.Comment: 4 page

Computing the first eigenpair of the p-Laplacian via inverse iteration of sublinear supersolutions

We introduce an iterative method for computing the first eigenpair $(\lambda_{p},e_{p})$ for the $p$-Laplacian operator with homogeneous Dirichlet data as the limit of $(\mu_{q,}u_{q})$ as $q\rightarrow p^{-}$, where $u_{q}$ is the positive solution of the sublinear Lane-Emden equation $-\Delta_{p}u_{q}=\mu_{q}u_{q}^{q-1}$ with same boundary data. The method is shown to work for any smooth, bounded domain. Solutions to the Lane-Emden problem are obtained through inverse iteration of a super-solution which is derived from the solution to the torsional creep problem. Convergence of $u_{q}$ to $e_{p}$ is in the $C^{1}$-norm and the rate of convergence of $\mu_{q}$ to $\lambda_{p}$ is at least $O(p-q)$. Numerical evidence is presented.Comment: Section 5 was rewritten. Jed Brown was added as autho

Axisymmetric versus Non-axisymmetric Vortices in Spinor Bose-Einstein Condensates

The structure and stability of various vortices in F=1 spinor Bose-Einstein condensates are investigated by solving the extended Gross-Pitaevskii equation under rotation. We perform an extensive search for stable vortices, considering both axisymmetric and non-axisymmetric vortices and covering a wide range of ferromagnetic and antiferromagnetic interactions. The topological defect called Mermin-Ho (Anderson-Toulouse) vortex is shown to be stable for ferromagnetic case. The phase diagram is established in a plane of external rotation Omega vs total magnetization M by comparing the free energies of possible vortices. It is shown that there are qualitative differences between axisymmetric and non-axisymmetric vortices which are manifested in the Omega- and M-dependences.Comment: 9 pages, 9 figure

Exploring relationships between shock-induced microstructures and H₂O and Cl in apatite grains from eucrite meteorites

The abundance and isotopic composition of volatile elements in meteorites is critical for understanding planetary evolution, given their importance in a variety of geochemical processes. There has been significant interest in the mineral apatite, which occurs as a minor phase in most meteorites and is known to contain appreciable amounts of volatiles (up to wt. % F, Cl, and OH). Impact-driven shock metamorphism, pervasive within many meteorites, can potentially modify the original signatures of volatiles through processes such as devolatilization and diffusion. In this study, we investigate the microstructures of apatite grains from six eucrites across a broad range of shock stages (S1–S5) using electron backscatter diffraction (EBSD) to explore shock-induced crystallographic features in apatite. New Cl and H abundance and isotopic composition data were collected on moderate to highly shocked samples (S3-S5) by Nano Secondary Ion Mass Spectrometry (NanoSIMS). Previously reported volatile data for S1 and S2 eucrites were integrated with EBSD findings in this study. Our findings indicate that apatite microstructures become increasingly more complex at higher shock stages. At low shock stages (S1–S2) samples display brecciation and fracturing of apatite. Samples in S3 and S4 display increasing crystal plastic deformation indicated by increasing spread in pole figures. At the higher shock stages (S4/S5) there is potential recrystallisation demonstrated by an increased density of subgrain boundaries. The Cl content and δ37Cl values of highly-shocked apatite grains range from ∼ 940–1410 ppm and – 3.38 to + 7.70 ‰, respectively, within the range observed in less-shocked eucrites. In contrast, H2O abundances are more variable (from 186 to ∼ 4010 ppm), however, the measured water content still falls within the range previously reported for low-shock eucrites. The measured δD values range from – 157 to + 163 ‰, also within the range of values from known low-shock basaltic eucrites. Weighted averages for both isotopic systems (δD − 122 ± 20 ‰, δ37Cl + 1.76 ± 0.66 ‰) are consistent with the range displayed in other inner Solar System bodies. NanoSIMS isotope images of apatite grains display heterogeneity in their Cl abundance at the nanoscale which increases in complexity with shock stage. This increasing complexity, however, does not correlate with deformation microstructures observed in EBSD or with the Cl isotopic composition at either an inter-grain or intra-grain scale. These findings are similar to analyses of variably shocked lunar apatite and, therefore, apatite appears to be a robust recorder of Cl and H (at least at spatial resolution and precision currently achievable by NanoSIMS) on airless bodies, despite intensive shock

Rotating spin-1 bosons in the lowest Landau level

We present results for the ground states of a system of spin-1 bosons in a rotating trap. We focus on the dilute, weakly interacting regime, and restrict the bosons to the quantum states in the lowest Landau level (LLL) in the plane (disc), sphere or torus geometries. We map out parts of the zero temperature phase diagram, using both exact quantum ground states and LLL mean field configurations. For the case of a spin-independent interaction we present exact quantum ground states at angular momentum $L\leq N$. For general values of the interaction parameters, we present mean field studies of general ground states at slow rotation and of lattices of vortices and skyrmions at higher rotation rates. Finally, we discuss quantum Hall liquid states at ultra-high rotation.Comment: 24 pages, 14 figures, RevTe

Development and external validation study of a melanoma risk prediction model incorporating clinically assessed naevi and solar lentigines

Background: Melanoma risk prediction models could be useful for matching preventive interventions to patients’ risk. Objectives: To develop and validate a model for incident first‐primary cutaneous melanoma using clinically assessed risk factors. Methods: We used unconditional logistic regression with backward selection from the Australian Melanoma Family Study (461 cases and 329 controls) in which age, sex and city of recruitment were kept in each step, and we externally validated it using the Leeds Melanoma Case–Control Study (960 cases and 513 controls). Candidate predictors included clinically assessed whole‐body naevi and solar lentigines, and self‐assessed pigmentation phenotype, sun exposure, family history and history of keratinocyte cancer. We evaluated the predictive strength and discrimination of the model risk factors using odds per age‐ and sex‐adjusted SD (OPERA) and the area under curve (AUC), and calibration using the Hosmer–Lemeshow test. Results: The final model included the number of naevi ≥ 2 mm in diameter on the whole body, solar lentigines on the upper back (a six‐level scale), hair colour at age 18 years and personal history of keratinocyte cancer. Naevi was the strongest risk factor; the OPERA was 3·51 [95% confidence interval (CI) 2·71–4·54] in the Australian study and 2·56 (95% CI 2·23–2·95) in the Leeds study. The AUC was 0·79 (95% CI 0·76–0·83) in the Australian study and 0·73 (95% CI 0·70–0·75) in the Leeds study. The Hosmer–Lemeshow test P‐value was 0·30 in the Australian study and < 0·001 in the Leeds study. Conclusions: This model had good discrimination and could be used by clinicians to stratify patients by melanoma risk for the targeting of preventive interventions. What's already known about this topic? Melanoma risk prediction models may be useful in prevention by tailoring interventions to personalized risk levels. For reasons of feasibility, time and cost many melanoma prediction models use self‐assessed risk factors. However, individuals tend to underestimate their naevus numbers. What does this study add? We present a melanoma risk prediction model, which includes clinically‐assessed whole‐body naevi and solar lentigines, and self‐assessed risk factors including pigmentation phenotype and history of keratinocyte cancer. This model performs well on discrimination, the model's ability to distinguish between individuals with and without melanoma, and may assist clinicians to stratify patients by melanoma risk for targeted preventive interventions

NMR and NQR Fluctuation Effects in Layered Superconductors

We study the effect of thermal fluctuations of the s-wave order parameter of a quasi two dimensional superconductor on the nuclear spin relaxation rate near the transition temperature Tc. We consider both the effects of the amplitude fluctuations and the Berezinskii-Kosterlitz-Thouless (BKT) phase fluctuations in weakly coupled layered superconductors. In the treatment of the amplitude fluctuations we employ the Gaussian approximation and evaluate the longitudinal relaxation rate 1/T1 for a clean s-wave superconductor, with and without pair breaking effects, using the static pair fluctuation propagator D. The increase in 1/T1 due to pair breaking in D is overcompensated by the decrease arising from the single particle Green's functions. The result is a strong effect on 1/T1 for even a small amount of pair breaking. The phase fluctuations are described in terms of dynamical BKT excitations in the form of pancake vortex-antivortex (VA) pairs. We calculate the effect of the magnetic field fluctuations caused by the translational motion of VA excitations on 1/T1 and on the transverse relaxation rate 1/T2 on both sides of the BKT transitation temperature T(BKT)<Tc. The results for the NQR relaxation rates depend strongly on the diffusion constant that governs the motion of free and bound vortices as well as the annihilation of VA pairs. We discuss the relaxation rates for real multilayer systems where the diffusion constant can be small and thus increase the lifetime of a VA pair, leading to an enhancement of the rates. We also discuss in some detail the experimental feasibility of observing the effects of amplitude fluctuations in layered s-wave superconductors such as the dichalcogenides and the effects of phase fluctuations in s- or d-wave superconductors such as the layered cuprates.Comment: 38 pages, 12 figure