2,441 research outputs found
COVID-19 catalysing assessment transformation: A case of the online open book examination
Under COVID-19 lockdown conditions, the imposition of social distancing and restricted mobility, disrupted the traditional way of assessment in higher education. The closed book examination, conducted under proctored conditions, had to be substituted for the online open book examination (OOBE), posing challenges to both conventional and Open Distance Learning (ODL) institutions. The OOBE became a new experience to lecturers and students. Considering COVID-19 as a potential catalyst for educational transformation, the experiences gained in this format of assessment presents a valuable frame of reference for future learning. The aim is to extract lessons from this innovative learning experience to inform future assessment practices. The study is set in the context of a B.Ed. (Hons) compulsory module, offered at an Open Distance Learning (ODL) institution in South Africa. It is guided by the research question: “what were students’ experiences of their first online, open-book final examination and what are the implications for policy, practice and research?” This is a qualitative study, using as data, student emails on their experiences of the OOBE. The results show that the OOBE is an innovative assessment practice in higher education, in need of deeper understanding and (re)training. We conclude that the OOBE offers transformational opportunities in higher education assessment practices, to replace the traditional closed-book examination. We make recommendations to assist lecturers and students in approaching the OOBE in future
An Ecological Dynamics perspective on Adventure Tourism
Traditional definitions for adventure tourism have focused on the adventure tourism activity or the adventure tourism environment. In these cases the activity is most often associated with risk and the environment associated with unfamiliarity and natural terrains. Critiques of these definitions have pointed out that this traditional perspective is limited. The risk focus is paradoxical as clients purchase adventure experiences involving risk and uncertainty, whereas tour operators must minimize the risk and emphasize safety. Additionally, adventure tourism can also take place in urban or man-made environments. Furthermore, the traditional definitions mostly ignore the lived experience of the adventure consumer. Individuals undertake adventure for a variety of reasons, including risk and thrills, health and well-being, connection to others and nature, recreational mastery, and personal development. We propose a nuanced conceptual understanding of adventure tourism within an ecological dynamics perspective that considers the relationship between the person, the adventure activity and the surrounding environment, and the recognition of affordances that support well-being. This theoretical approach provides a useful framework for operators and researchers that encourages a more personalized and meaningful experience for the tourist
Dietary fibre enrichment of supplemental feed modulates the development of the intestinal tract in suckling piglets
Background: Commercial pre-weaning diets are formulated to be highly digestible and nutrient-dense and contain low levels of dietary fibre. In contrast, pigs in a natural setting are manipulating fibre-rich plant material from a young age. Moreover, dietary fibre affects gastrointestinal tract (GIT) development and health in older pigs. We hypothesised that supplemental diets that contain vegetal fibres are accelerating GIT development in suckling piglets in terms of size and functionality. From d 2 of life, sow-suckled piglets had access to a low fibre diet (CON), a diet with a fermentable long-chain arabinoxylan (lc-AXOS), a diet with a largely non-fermentable purified cellulose (CELL), or a diet containing both fibres. During the initial 2 weeks, the control diet was a high-density milk replacer, followed by a dry and highly digestible creep meal. Upon weaning at 25 d, 15 piglets from each treatment group, identified as eaters and originating from six or seven litters, were sacrificed for post-mortem examination of GIT morphology, small intestinal permeability and metabolic profile of the digesta. The microbiota composition of the mid-colon was evaluated in a sub-set of ten piglets.
Results: No major statistical interactions between the fibre sources were observed. Piglets consumed the fibre-containing milk supplements and creep diets well. Stomach size and small intestinal permeability was not affected. Large intestinal fill was increased with lc-AXOS only, while relative large intestinal weight was increased with both fibre sources (P < 0.050). Also, CELL decreased ileal pH and tended to increase ileal DM content compared to CON (P < 0.050). Moreover, the concentration of volatile fatty acids was increased in the caecum (P < 0.100) and mid-colon (P < 0.050) by addition of CELL. lc-AXOS only stimulated caecal propionate (P < 0.050). The microbiota composition showed a high individual variation and limited dietary impact. Nonetheless, CELL induced minor shifts in specific genera, with notable reductions of Escherichia-Shigella.
Conclusions: Adding dietary fibres to the supplemental diet of suckling piglets altered large intestinal morphology but not small intestinal permeability. Moreover, dietary fibre showed effects on fermentation and modest changes of microbial populations in the hindgut, with more prominent effects from the low-fermentable cellulose
Effects of textured socks on balance control during single-leg standing in healthy adults
Balance is important in many activities of daily living and sports movements. Texture, added to shoe insole material, has been shown to improve balance in young, older and pathological populations. The aim of this study was to develop and test textured socks, which might have several potential benefits over insole use including: they can be worn without, or transferred between,shoes, and texture can be applied to areas of the foot other than the plantar surface. Prototypes socks were made with nodules (5
mm diameter) sewn onto socks on: 1) the plantar surface, 2) the dorsal surface, 3) sides of the foot and 4) covering the entire surface. Participants (n=13) performed three single-legged stance trials, standing on a force platform. with eyes open and eyes closed, whilst wearing each of the prototype socks and a control sock. Balance was quantified using the postural time-toboundary measure. Results revealed a trend towards improved balance in the Sides sock condition (eyes open d = 0.62, eyes closed d = 0.51) conditions. This finding supported previous data from studies showing benefits of wearing insoles with plastic
tubing around the perimeter of the foot, suggesting that textured socks might be useful as an intervention to improve balance
Hindrance of Heavy-ion Fusion at Extreme Sub-Barrier Energies in Open-shell Colliding Systems
The excitation function for the fusion-evaporation reaction 64Ni+100Mo has
been measured down to a cross-section of ~5 nb. Extensive coupled-channels
calculations have been performed, which cannot reproduce the steep fall-off of
the excitation function at extreme sub-barrier energies. Thus, this system
exhibits a hindrance for fusion, a phenomenon that has been discovered only
recently. In the S-factor representation introduced to quantify the hindrance,
a maximum is observed at E_s=120.6 MeV, which corresponds to 90% of the
reference energy E_s^ref, a value expected from systematics of closed-shell
systems. A systematic analysis of Ni-induced fusion reactions leading to
compound nuclei with mass A=100-200 is presented in order to explore a possible
dependence of the fusion hindrance on nuclear structure.Comment: 10 pages, 9 figures, Submitted to Phys. Rev.
Calcific uraemic arteriolopathy (calciphylaxis) in patients on renal replacement therapy
Background. Calcific uraemic arteriolopathy (calciphylaxis) is an unusual and potentially fatal condition characterised by small-vessel calcification and ischaemic skin necrosis. It mainly affects patients with end-stage renal disease (ESRD) on haemodialysis, but may rarely occur in the absence of ESRD in conditions such as primary hyperparathyroidism, malignancy, alcoholic liver disease and connective tissue disease.Methods. We reviewed the records of all patients diagnosed with calciphylaxis while on renal replacement therapy at Tygerberg Hospital, Cape Town, South Africa, between 1990 and 2014, to describe its presentation, course and final outcome.Results. Nineteen patients developed calciphylaxis over this period. Their median age was 34 years and 13 (68.4%) were female. Fifteen (78.9%) had received a kidney transplant. All patients had painful skin lesions that rapidly progressed to infarction. Small-vessel calcification was seen on skin biopsy in 13 patients. Twelve patients had hyperparathyroidism. Several of the transplanted patients had been treated for graft rejection in the year preceding the diagnosis. Treatment consisted of good wound care and efforts to normalise serum calcium and phosphate levels. Five patients received an urgent parathyroidectomy. The outcome was fatal in 17 patients, with sepsis being the main cause of death.Conclusions. In our patients, calciphylaxis carried a worse prognosis than previously reported internationally. It should always be considered in the differential diagnosis of painful skin lesions in the dialysis or transplant patient
Modal Approach to Casimir Forces in Periodic Structures
We present a modal approach to calculate finite temperature Casimir
interactions between two periodically modulated surfaces. The scattering
formula is used and the reflection matrices of the patterned surfaces are
calculated decomposing the electromagnetic field into the natural modes of the
structures. The Casimir force gradient from a deeply etched silicon grating is
evaluated using the modal approach and compared to experiment for validation.
The Casimir force from a two dimensional periodic structure is computed and
deviations from the proximity force approximation examined.Comment: 13 pages, 7 figure
Spin Networks for Non-Compact Groups
Spin networks are natural generalization of Wilson loops functionals. They
have been extensively studied in the case where the gauge group is compact and
it has been shown that they naturally form a basis of gauge invariant
observables. Physically the restriction to compact gauge group is enough for
the study of Yang-mills theories, however it is well known that non-compact
groups naturally arise as internal gauge groups for Lorentzian gravity models.
In this context a proper construction of gauge invariant observables is needed.
The purpose of this work is to define the notion of spin network states for
non-compact groups. We first built, by a careful gauge fixing procedure, a
natural measure and a Hilbert space structure on the space of gauge invariant
graph connection. Spin networks are then defined as generalized eigenvectors of
a complete set of hermitic commuting operators. We show how the delicate issue
of taking the quotient of a space by non compact groups can be address in term
of algebraic geometry. We finally construct the full Hilbert space containing
all spin network states. Having in mind application to gravity we illustrate
our results for the groups SL(2,R), SL(2,C).Comment: 43pages, many figures, some comments adde
Time-dependent properties of proton decay from crossing single-particle metastable states in deformed nuclei
A dynamical study of the decay of a metastable state by quantum tunneling
through an anisotropic, non separable, two-dimensional potential barrier is
performed by the numerical solution of the time-dependent Schrodinger equation.
Initial quasi- stationary proton states are chosen in the framework of a
deformed Woods-Saxon single-particle model. The decay of two sets of states
corresponding to true and quasi levels-crossing is studied and the evolution of
their decay properties as a function of nuclear deformation is calculated
around the crossing point. The results show that the investigation of the
proton decay from metastable states in deformed nuclei can unambiguously
distinguish between the two types of crossing and determine the structure of
the nuclear states involved.Comment: 15 pages, 9 figures, submitted to Phys. Rev.
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