Monitoring students’ growth using system dynamics

Researchers have long been trying to analyze the problems associated with the teaching processes at universities. Most such research is focused on trying to understand the problems associated with teaching and analyzing the impacts of these problems on student learning. However, little work has been done in modelling the teaching/learning process to understand how different problems affect the knowledge gained by the students. The problems may impact students’ motivational development, teachers’ teaching interest or even students’ learning process. In this paper, we propose a model that we use to simulate the existing teaching process at universities, using system dynamics. We demonstrate that an analysis of different parameters extracted from academic, personal and motivational fronts using system dynamics can provide a clear picture of the influence of real life events on students’ performance. System dynamics helped us to monitor the students’ growth over the duration of a course, guiding us to analyze the root cause of the problems. As a result, system dynamics helps to provide a solution for efficiently dealing with students’ difficulties. The results show various trends among teachers’ enthusiasm, students’ enthusiasm, students’ knowledge, test anxiety, teaching quality and students’ performance over time. For example, teachers’ enthusiasm reduces by approximately 4% when teachers’ mental stress increases by 10%

Effect of obesity on autonomic nervous system

The present study was carried out on 100 volunteers of which 50 subjects with BMI > 30kg/m2 were included in study group and 50 subjects with BMI < 30kg/m2 (non obese) were included in control group. The functioning of Autonomic nervous system was evaluated by six non-invasive tests- four of which were based mainly on parasympathetic control (30:15 ratio, standing to lying ratio (S/L ratio), expiration/inspiration ratio (E/I ratio) and valsalva maneuver) and two on sympathetic control (Blood pressure response to standing and cold pressor test). The results of the present study showed significantly low (p=0.001) S/L ratio in study group (1.04 ± 0.12) when compared to controls (1.12 ± 0.11) indicating impaired parasympathetic function. The mean change in sytolic blood pressure before and after cold pressor test (CPT) was less in study group (7.12 ± 5.28) as compared to control group (10.38 ± 6.35) and this was statistically significant (p=0.006) indicating impaired sympatheitc function. Thus ,in obese both division of ANS are affected which may be the cause of various cardiovascular complications

Effect of Graphene Interface on Potassiation in a Graphene- Selenium Heterostructure Cathode for Potassium-ion Batteries

Selenium (Se) cathodes are an exciting emerging high energy density storage system for Potassium ion batteries(KIB), where potassiation reactions are less understood. Here, we present an atomic-level investigation of KxSe cathode enclosed in hexagonal lattices of carbon(C) characteristic of multilayered graphene matrix and multiwalled carbon nanotubes (MW-CNTs). Microstructural changes directed by graphene substrate in KxSe cathode are contrasted with graphene-free cathode. Graphene's binding affinity for long-chain polyselenides (Se-Se-Se = -2.82 eV and Se-Se = -2.646 eV) and ability to induce reactivity between Se and K are investigated. Furthermore, intercalation voltage for graphene enclosed KxSe cathode reaction intermediates are calculated with K2Se as the final discharged product. Our results indicate a single-step reaction near a voltage of 1.55 V between K and Se cathode. Our findings suggest that operating at higher voltages (~2V) could result in the formation of reaction intermediates where intercalation/deintercalation of K could be a challenge, and therefore cause irreversible capacity losses in the battery. Primary issues are the high binding energy of long-chain polyselenides with graphene that discourage K storage and Se-Se bond dissociation at low K concentrations. A comparison with graphene-free cathode highlights the substantial changes a van der Waals (vdW) graphene interface can bring in atomic-structure and electrochemistry of the KxSe cathode.Comment: 7 Figures and 1 Tabl

Comparison of the long bone microstructure of two southern African marine birds, the Cape gannet (Morus capensis) and the African penguin (Spheniscus demersus) with respect to their aquatic adaptations

The Cape gannet (Morus capensis) and the African penguin (Spheniscus demersus) have distinct aquatic adaptations for locomotion. The gannet, which is an efficient flying bird, uses both fore- and hind limbs to propel itself under water. On the other hand, the flightless penguin swims underwater using only its forelimbs. In this study, the long bones of ten penguins and nine gannets were compared in terms of microanatomy and histology with respect to ontogenetic stage (hatchlings, juveniles and adults) and locomotion. Micronatomical and histological findings of the fore-limbs and hind limbs show that the bone microstructure of the gannets and the penguins differs significantly in term of compactness and bone remodelling. Penguin bones are more thick-walled and compact as compared to gannet bones and their cortical tissue is dominated by simple vascular canals whilst the medullary cavity is nearly absent. The forelimb bones of penguins are more compact that the hind limb bones. This is due to the aquatic adaptation of the bone to fore-limb underwater propulsion. On the other hand, the gannet bones are thin walled, less compact with primary osteons dominating the mid-cortex, and a large vacant medullary cavity is present. The gannet fore- and hind limb bones do not differ in terms of bone compactness. Ontogenetic differences in the penguin long bones show that the hatchling bears an active growth phase. Some of the bones of the juvenile penguins are still actively growing whilst the adult ones appear to have stopped growing as the bone mid-cortex is more organized. For the gannet species, the juvenile and adult differs in terms of the presence and thickness of the inner and outer circumferential layers and the presence of circumferential vascularizations. Intra-specific differences are noted in the juvenile penguins with one specimen still undergoing active growth depicted by the presence of numerous simple vascular canals. Amongst the adult penguins, one male specimen is actively molting as indicated by the presence of large resorption cavities in all of the long bones. One adult gannet individual possesses large resorption cavities in all its long bones as a result of starvation caused by perforation of its intestines. Inter-skeletal differences are noted with the stylopod and zeugopod being the most affected by sub-aquatic locomotion with osteosclerosis occurring the most in the proximal bone and decreases in the distal bones going from the pectoral to the pelvic bones in the African penguin. In the Cape gannet, the stylopod and ulna have micro-structural features for torsional resistance during flight

The evolution of haemoglobin gene loci in amniotes

The genes in alpha ({u03B1})- and beta ({u03B2})- globin clusters constitute a functional haemoglobin molecule, crucial for oxygen transportation. In most fish and amphibians, {u03B1}- and {u03B2}-globin genes are located together, whereas in amniotes (birds and mammals), there are two distinct clusters. Several complex models have been proposed to explain the evolution of these gene clusters. However, there was a lack of data for key positions in amniote phylogeny to discern which one was most parsimonious. Therefore, the main aims of this project were to characterise {u03B1}- and {u03B2}-globin clusters and their regulatory regions in a monotreme Ornithorhynchus anatinus (Australian duck-billed platypus) and two reptilian species Pogona vitticeps (Australian bearded dragon) and Anolis carolinensis (green anole lizard), to gain insight into globin loci evolution. This thesis is presented as a collection of research papers covering each topic, and a review and discussion that summarises my research. The first paper (Chapter 2) reports a comprehensive study on the characterisation, expression and evolution of {u03B1}- and {u03B2}-globin gene clusters in the platypus, using a combination of molecular and bioinformatics approaches. The most important findings from this work leading to the development of a new and simple model for globin gene evolution concerned the discovery of a {u03B2}-like globin gene within the a-globin cluster and genomic context analysis of {u03B1}- and {u03B2}-globin clusters across vertebrates. I showed that the amniote a-globin cluster is in fact the same as the a-{u03B2} cluster found in fish and amphibians, and both clusters share common flanking genes (C16orf35 and LUC7L). I proposed a transposition model in which a copy of {u03B2}-globin gene was inserted into a cluster of olfactory receptors (flanked by RRMl, CCKBR and ILK) in the ancestor of amniotes, thus originating the amniote {u03B2}-globin cluster. To elaborate this model further, my second paper (Chapter 3) reviews some events that could have led to this transposition, and their effects on the current fate of regulation. Information on the organization of globin genes in reptiles was required to test this transpositional model. I looked into the globin gene organization in the green anole using a bioinformatics approach and in the bearded dragon using a molecular approach. The results are reported in Chapter 4 and my third paper, which describe how fragmentary data from the green anole genome sequence assembly and mapping data from bearded dragon provided further evidence to support my proposed model for the evolution of the {u03B2}-globin gene cluster in amniotes. I also studied the evolution of regulatory regions of the platypus {u03B1}- and {u03B2}-globin clusters to address the question whether the translocation of the {u03B2}-globin locus resulted in a transposition of its regulatory region, or whether a new regulatory region evolved as a result of this translocation (reported in the fourth paper, Chapter 5). By using some novel techniques, I showed that the platypus a-globin has a major regulatory element that is conserved with other jawed vertebrates, whereas the regulatory regions of their {u03B2}-globin cluster do not show any conservation at the sequence level to those of birds and therian mammals. This suggested that the regulatory regions of amniote {u03B2}-globin genes evolved either more rapidly (more substitutions) or more extensively (e.g. more rearrangements) from a common ancestral regulatory region. Alternatively, these regulatory regions may have independent origins in different amniote lineages. In my final chapter, I discuss the overall implications of my findings on this area of research. I highlight the special value of studying non-model species mammals and reptiles, by which researchers are able to gain novel information about globin evolution and regulation

Life cycle and host preferences in the Agapanthus borer (Neuranethes spodopterodes)

The species Neuranethes spodopterodes is a pest of the Agapanthus species. The larva feeds gregariously on the leaves and rhizomes and cause extensive damage to the plant. This study shows the N.spodopterodes have 6 larval instars. The use of the head capsule width as a morphometric parameter and applying it to Dyar‟s rule gives significant results which allow for adequate determination of the larval instar. The Agapanthus borer has a life cycle that last approximately 84 days. Some species of Agapanthus are the preferred host plant for oviposition by the female N.spodopterodes. Agapanthus inapertus, Agapanthus caulescens and Agapanthus praecox are the most infested with the Agapanthus borer eggs. Leaf sizes do not appear to be a factor that influences the female choice. There appears to be no preference from the larva during feeding. The larva fed equally on all the six Agapanthus species including A. africanus (p&gt;0.05). This shows that the chemical composition of these species is closely related. Since the larva has no feeding preference, this reinforces the fact that it is the female moth that chooses the host plant and that it abides with preference-performance hypothesis. Since A. africanus is subjected to feeding by the larva under laboratory conditions, it could potential imply that in the event of a range shift by the gravid female, that this species of plant is at risk of extinction. The presence of a parasitoid wasp, Trichogramma in the egg of N. spodopterodes and that the level of parasitism is about 86% suggests that this parasitoid could potentially be used as a biological control agent of the Agapanthus borer