Across two experiments I sought to determine the relation between the Imitation developmental cusp and the emulative echoic cusp in preschoolers classified with a learning disability. In Experiment I, the participants were 36 preschoolers selected via a convenience sample, where the goal was to test for relations between the preverbal developmental cusp and foundational learning capability of Imitation, the preverbal and emulative verbal developmental cusps in the participant’s repertoire, and the reinforcement value of age-appropriate toys and activities. Results showed significant correlations between Imitation and conditioned reinforcement for observing adult faces and voices, parroting, echoics, and listener literacy, as well as significant relations between Imitation and conditioned reinforcement for playing with toys, puzzles, coloring materials, and Play-Doh. Findings show that Imitation is either a prerequisite or a corequisite to emulative verbal developmental cusps. Experiment II had two goals. The first was to determine whether educationally classified preschoolers with a disability can emit various imitative responses when the researcher presents instruction through a smart device using the mirror training protocol. The second was to determine whether the echoic behavior and observing responses of the participants would change as a result of undergoing the synchronous mirror training protocol. Results show a functional relation between the acquisition of the verbal foundational Imitation cusp and increases in emission of various imitative responses and emulative echoic responses, across both in-person and virtual conditions.

Detta examensarbete handlar om att få ökad förståelse om hur pedagoger ser på skapande material i verksamheten och närmare bestämt om pedagogerna har något didaktisk tanke när de låter barnen arbeta med play doh deg.Genom kvalitativa intervjuer med pedagoger på olika förskolor har jag undersökt hur de arbetar med skapande material på förskolan och hur de tänker kring barnens lärande i skapande. För att få bredare förståelse valde jag pedagoger som arbetar både med de minsta barnen och de något äldre barnen.Resultatet visar att pedagogerna är mycket positiva till skapande material och ser det som brett område som kan vara användbart till mycket. De upplever play doh som ett billigt och bra material som man lätt kan fixa själv på förskolan. De upplever att barnen tycker att det är roligt att dega, det infinner sig ett lugn hos dem och de ser även att kräver koncentration och sätter igång fantasin hos barnen. Alla barn kan vara med och utforska degen på sitt sätt oavsett ålder, vilket bidrar till att det är ett demokratiskt material. Det bidrar till ett stort lärande hos barnen både genom språket, matematiken och tekniken, samt utvecklar samarbetsförmågan. / This study examines how working educators understand and use creative material and if they have any didactic thoughts when they let children use a material such as Play Doh.By using qualitative interviews with teachers from different pre-schools I have examined how they use creative material in pre-school and their conceptions of children´s learning during creative activities. In order to get a wider perspective and understanding I have chosen to conduct interviews with pre-school teachers working with both toddlers and older children.The result shows that the working educators have a very positive experience of creative material and see creative work as a useful tool for learning in many ways. They also view the material as a cheap and easy way to get children to express themselves. From the working educators' point of view, the children find it very amusing and become calm, concentrated and use their imagination to the edge. Despite age, every child is able to explore and use the material, which makes it a democratic material. This contributes to a large amount of learning both regarding language, math and technique and also develops an ability to work together with other children.

DNS over HTTPS (DoH) is a protocol used to send traditional DNS traffic over HTTPS. This causes the DNS name resolving traffic to be encrypted and transmitted over the same port as regular HTTPS traffic. This thesis maps a number of previous vulnerabilities in DNS and compares those risks with the DoH protocol and its implementation, mainly focusing on cache poisoning. A number of attacks from a DoH server to a DoH client are applied. The results show that it is possible to inject incorrect data into the DoH client’s cache. The consequences of this can be extensive, an example of this is a redirect to a malicious webpage, which when using DoH can be difficult to detect because the DNS traffic is encrypted. Further work is needed to mitigate the security holes discovered, as well as to further identify potential threats.

Background Iron deficiency (ID) is the world‟s most prevalent micronutrient deficiency and predominantly affects developing countries, also South Africa. In areas with low fish consumption and high n-6 PUFA vegetable oil intake, there is a risk for having inadequate n-3 PUFA status. Both iron and n-3 PUFA play important roles in the immune response, and supplementation is a strategy to alleviate deficiencies. However, little is known about potential interactive effects between concurrent iron and n-3 PUFA supplementation on the immune system. This is also important in the context that iron supplementation may be unsafe and may increase morbidity and mortality. Aim The overall aim of this thesis was to assess the effects of iron and docosahexaenoic (DHA)/eicosapentaenoic acid (EPA) supplementation, alone and in combination, on the immune system of ID children. More specifically, these effects were investigated on the occurrence and duration of illness and school-absenteeism due to illness, peripheral blood mononuclear cell (PBMC), red blood cell (RBC) and plasma total phospholipid fatty acid composition, iron status, fatty acid-derived immune modulators and targeted PBMC gene expression. Furthermore, association of PBMC, RBC and plasma total phospholipid fatty acid composition with allergic disease, were also examined. Design In a 2-by-2 factorial, randomised, double-blind, placebo-controlled trial, South African children (n = 321, aged 6–11 y) were randomly assigned to receive oral supplements of either 1) iron (50 mg as ferrous sulphate) plus placebo; 2) DHA/EPA (420/80 mg) plus placebo; 3) iron plus DHA/EPA (420/80 mg); or 4) placebo plus placebo for 8.5 mo, four times per week. Absenteeism and illness symptoms were recorded and biochemical parameters for compliance as well as parameters fundamental to immune function were assessed at baseline and endpoint. Furthermore, in a cross-sectional design, associations of allergic disease with baseline fatty acid composition of PBMC, RBC and plasma were examined. Results The combination of iron and DHA/EPA significantly attenuated respiratory illness caused by iron supplementation. DHA/EPA supplementation alone improved respiratory symptoms at school, but increased headache-related absenteeism. DHA/EPA and iron supplementation individually tended to increase and decrease anti-inflammatory DHA and EPA-derived mediators, respectively. Furthermore the anti-inflammatory DHA-derived immune mediator, 17HDHA was higher in the DHA/EPA plus placebo and iron plus DHA/EPA groups than in the iron plus placebo group. Also, the pro-inflammatory arachidonic acid (AA)-derived modulators (5- and 15-hydroxyeicosapentaenoic acid) were significantly lower in the iron plus DHA/EPA group compared to the placebo plus placebo groups. In the study population, 27.2% of the children had allergic disease and AA in PBMC phospholipids was significantly lower in the allergic children than in the non-allergic children. In RBC phospholipids dihomo-gamma-linolenic acid (DGLA) and the ratio of DGLA: linoleic acid (LA) correlated negatively and the n-6:n-3 PUFA ratio positively with total immunoglobulin E (tIgE). Furthermore, trans-C18:1n-9, tended to be higher in the allergic group. Conclusion DHA/EPA prevented respiratory illness caused by iron supplementation and although DHA/EPA on its own reduced respiratory morbidity when the children were present at school, surprisingly it increased the likelihood of being absent with headache and fever. The biochemical findings compliment the clinical results and support previous observations about DHA/EPA supplementation to reduce inflammation, but add to the current knowledge base that a relatively high oral dose of non-haem iron modulates circulating lipid-derived immune modulators and related gene expression. Furthermore, when supplementing with iron and DHA/EPA combined, in this ID population with low fish intake, the anti-inflammatory effect of DHA/EPA is maintained concurrently with attenuation of respiratory morbidity. This finding support the notion that excess iron (probably as non-transferrin bound iron) becomes available for pathogens and is probably why we found that iron increased respiratory infectious morbidity. The improved clinical outcome with combined supplementation seems to be related to increased lipid-mediator synthesis gene expression and the availability of DHA/EPA, leading to a more pro-resolving profile and enhanced immune competence. Overall these results give better insight into immune function and infectious morbidity in relation to n-3 PUFA and iron status and treatment, as well as the possible association of fatty acid status with allergic disease in young South-African school children. / PhD (Nutrition), North-West University, Potchefstroom Campus, 2015

Background Iron deficiency (ID) is the world‟s most prevalent micronutrient deficiency and predominantly affects developing countries, also South Africa. In areas with low fish consumption and high n-6 PUFA vegetable oil intake, there is a risk for having inadequate n-3 PUFA status. Both iron and n-3 PUFA play important roles in the immune response, and supplementation is a strategy to alleviate deficiencies. However, little is known about potential interactive effects between concurrent iron and n-3 PUFA supplementation on the immune system. This is also important in the context that iron supplementation may be unsafe and may increase morbidity and mortality. Aim The overall aim of this thesis was to assess the effects of iron and docosahexaenoic (DHA)/eicosapentaenoic acid (EPA) supplementation, alone and in combination, on the immune system of ID children. More specifically, these effects were investigated on the occurrence and duration of illness and school-absenteeism due to illness, peripheral blood mononuclear cell (PBMC), red blood cell (RBC) and plasma total phospholipid fatty acid composition, iron status, fatty acid-derived immune modulators and targeted PBMC gene expression. Furthermore, association of PBMC, RBC and plasma total phospholipid fatty acid composition with allergic disease, were also examined. Design In a 2-by-2 factorial, randomised, double-blind, placebo-controlled trial, South African children (n = 321, aged 6–11 y) were randomly assigned to receive oral supplements of either 1) iron (50 mg as ferrous sulphate) plus placebo; 2) DHA/EPA (420/80 mg) plus placebo; 3) iron plus DHA/EPA (420/80 mg); or 4) placebo plus placebo for 8.5 mo, four times per week. Absenteeism and illness symptoms were recorded and biochemical parameters for compliance as well as parameters fundamental to immune function were assessed at baseline and endpoint. Furthermore, in a cross-sectional design, associations of allergic disease with baseline fatty acid composition of PBMC, RBC and plasma were examined. Results The combination of iron and DHA/EPA significantly attenuated respiratory illness caused by iron supplementation. DHA/EPA supplementation alone improved respiratory symptoms at school, but increased headache-related absenteeism. DHA/EPA and iron supplementation individually tended to increase and decrease anti-inflammatory DHA and EPA-derived mediators, respectively. Furthermore the anti-inflammatory DHA-derived immune mediator, 17HDHA was higher in the DHA/EPA plus placebo and iron plus DHA/EPA groups than in the iron plus placebo group. Also, the pro-inflammatory arachidonic acid (AA)-derived modulators (5- and 15-hydroxyeicosapentaenoic acid) were significantly lower in the iron plus DHA/EPA group compared to the placebo plus placebo groups. In the study population, 27.2% of the children had allergic disease and AA in PBMC phospholipids was significantly lower in the allergic children than in the non-allergic children. In RBC phospholipids dihomo-gamma-linolenic acid (DGLA) and the ratio of DGLA: linoleic acid (LA) correlated negatively and the n-6:n-3 PUFA ratio positively with total immunoglobulin E (tIgE). Furthermore, trans-C18:1n-9, tended to be higher in the allergic group. Conclusion DHA/EPA prevented respiratory illness caused by iron supplementation and although DHA/EPA on its own reduced respiratory morbidity when the children were present at school, surprisingly it increased the likelihood of being absent with headache and fever. The biochemical findings compliment the clinical results and support previous observations about DHA/EPA supplementation to reduce inflammation, but add to the current knowledge base that a relatively high oral dose of non-haem iron modulates circulating lipid-derived immune modulators and related gene expression. Furthermore, when supplementing with iron and DHA/EPA combined, in this ID population with low fish intake, the anti-inflammatory effect of DHA/EPA is maintained concurrently with attenuation of respiratory morbidity. This finding support the notion that excess iron (probably as non-transferrin bound iron) becomes available for pathogens and is probably why we found that iron increased respiratory infectious morbidity. The improved clinical outcome with combined supplementation seems to be related to increased lipid-mediator synthesis gene expression and the availability of DHA/EPA, leading to a more pro-resolving profile and enhanced immune competence. Overall these results give better insight into immune function and infectious morbidity in relation to n-3 PUFA and iron status and treatment, as well as the possible association of fatty acid status with allergic disease in young South-African school children. / PhD (Nutrition), North-West University, Potchefstroom Campus, 2015