Western larch (Larix occidentalis Nutt.) is a locally important species in the Nelson Forest Region, and to a lesser extent, in the Kamloops Forest Region. Its range extends from west of the Rockies to Okanagan Lake, and north to Salmon Arm, in the IDF, ICH, MS, and ESSF biogeoclimatic zones. Prior to this study, the site index curves developed for western larch in western Montana were used to model height and estimate site index in British Columbia. It has been suggested that these curves may not adequately reflect the height growth patterns of western larch in BC. Differences could arise from genetics, different methods of selecting sample trees, or climatic differences. The objective of this project was to produce accurate height growth models for western larch in BC.

Height growth models of coastal low- and mid-elevation Pacific silver fir, low-elevation white spruce, and low- and midelevation lodgepole pine have been used for predicting productivity of subalpine fir, Engelmann spruce, and lodgepole pine, respectively. These models, however, are biased in predicting height growth of high-elevation subalpine fir, Engelmann spruce, and lodgepole pine. To improve this situation, 329 sample plots (165 for subalpine fir, 90 for Engelmann spruce, and 74 for lodgepole pine) were located throughout the Engelmann Spruce-Subalpine Fir (ESSF) zone. Stem analysis was carried out on three dominant trees in each 0.04 ha sample plot. For each study species, a height growth model was developed on the data from two-thirds of the sample plots using the conditioned Chapman-Richards’ function; the model was validated using the remaining one-third of the sample plots.

Un nombre significatif d’enfants autistes ont une macrocéphalie. Malgré plusieurs études du périmètre crânien en autisme, peu d’études ont été faites sur des adultes. Aussi, les références actuelles en périmètre crânien (PC) adulte datent d’environ 20 ans. Les objectifs de cette étude étaient de construire une échelle de référence du PC adulte, et de comparer les taux de macrocéphalie entre un groupe d’adultes autistes et un groupe d’adultes neurotypiques. Dans cette étude, 221 sujets masculins adultes étaient recrutés de différents milieux afin de déterminer le meilleur modèle prédictif du PC et de construire l’échelle de référence. La hauteur et le poids étaient mesurés pour chaque participant afin de déterminer leur influence sur les dimensions crâniennes. Pour la partie comparative, 30 autistes et 36 sujets neurotypiques, tous adultes, étaient recrutés à partir de la base de données du laboratoire de recherche. Pour l’échelle de référence, les résultats démontraient des corrélations positives entre le PC avec la hauteur et le poids. Après analyse, la corrélation conjointe de la hauteur et du poids sur le PC a été déterminée comme étant le modèle qui offre les résultats les plus significatifs dans la prédiction du PC. Pour la partie comparative, les taux de macrocéphalie atteignaient 10,00% chez les autistes contre 2,56% chez les neurotypiques selon la formule de régression linéaire obtenue du modèle. Cependant le test d’exactitude de Fisher n’a révélé aucune différence significative entre les 2 groupes. Mes résultats suggèrent qu’il est nécessaire de considérer la hauteur et le poids en construisant une référence du PC et que, même en utilisant la nouvelle référence, les taux de macrocéphalie demeurent plus élevés chez les autistes adultes que chez les adultes neurotypiques en dépit de l’absence de différences significatives. / A significant proportion of autistic children have macrocephaly. Despite numerous head circumference studies in autism, few studies in adults exist. Also, current adult head circumference (HC) references are around 20 years old. The purposes of this study were to construct an adult head measurement reference chart, and to compare macrocephaly rates between a group of autistic adults and a group of typically developing adults. In this study, 221 male adults were recruited from various settings in order to determine the best predictive model for HC and to construct the reference chart. Height and weight were measured for each participant in order to evaluate their influence on head dimensions. For the comparison part, 30 autistic and 36 typically developing adult subjects were recruited from within the research lab’s database. For the reference chart, results showed positive correlations between HC, and both height and weight. After analysis, the combined influence of both height and weight on HC size has was determined to be the model showing most significant results in predicting HC. For the comparison part, macrocephaly rates reached 10.00% in the autistic group against 2.56% in the control group according to the linear regression formula obtained from the model. However, the Fisher’s exact test revealed no significant difference in macrocephaly rates between both groups. My results suggest the necessity of considering both height and weight when constructing a head circumference reference chart and that, even using a new reference, macrocephaly rates remain higher than normal in autistic adults although not significantly different enough from the typically developing adults.

Metabolic syndrome is a cluster of disorders including central obesity, hypertension, dyslipidemia, and hyperglycemia. Today's metabolic syndrome definitions identify central obesity by waist circumference (WC) measurements. A recent pilot study suggests that cut-points derived from a waist-to-height ratio (WHtR), or Index of Central Obesity (ICO), is a more accurate measurement of central obesity. This study compared the association between the metabolic syndrome components and central obese parameters (ICO and WC) among the white, black, and Hispanic adults in the United States. The subjects' data was obtained from the 2005-2006 National Health and Nutrition Examination Survey. ICO was highly correlated with metabolic syndrome components among white subjects and the least correlated in Hispanic subjects. Multivariate logistic regression analysis did not indicate that ICO was a better parameter for metabolic syndrome than WC. Other WHtR cut-points may be more sensitive in predicting metabolic syndrome components than the values used in this study.

Aim of the work: to explain possibilities of natural birch regeneration if clearcut areas, to detect main influencing factors and their intensity. Object of the work: Clearcut areas from 1996, 1999 and 2002 of site types Lfs and Lds of Pakruojis State Forest Enterprise. Methods: for analysis of regeneration quality, rectangular sample plots were selected. They were placed in the clearcut areas 20, 40 and 60 metres from their western edge. The density, height and age of sapling according to tree species was determined. Saplings were evaluated according to their growth conditions: prepared or unprepared soil. Dependence of saplings density on the stand from western side as well as dependence saplings density and height on precedent stand was investigated. Research data was processed using methods of dispersive and regression analysis. Results: it was determined, that regeneration of birch depends on site type and precedent stand, soil preparation, stand from western site of the clearcut. Soil preparation, stand from western site of the clearcut have the biggest influence on birch saplings density. Height of birch saplings depends on soil preparation and soil type. Distance from stand edge have no influence on birch natural regeneration.

Disertaciją sudaro darbai, autoriaus atlikti 2006-2013 metais. Šiuos darbus jungianti tema yra algebrinių kreivių, apibrėžtų virš racionaliųjų skaičių, šeimos, einančios per taškus, kurių koordinatės priklauso duotam skaičių kūnui ar jo sveikųjų skaičių žiedui. Pirmoje disertacijos dalyje yra gaunama vidutinio mažo aukščio racionaliųjų taškų kiekio ant fiksuoto žanro hiperelipsinių kreivių asimptotika. Antroje dalyje šis rezultatas išplečiamas, apibūdinant vidutinį homogeninių daugianarių reikšmių taškuose, kurių koordinatės yra mažo aukščio tarpusavyje pirminiai skaičiai, sutampančių su duoto vieno kintamojo daugianario reikšmėmis sveikuosiuose taškuose, skaičių. Trečioje dalyje sukonstruojamos nedidelės kreivių, apibrėžtų virš racionaliųjų skaičių ir išvengiančių taškų, kurių koordinatės priklauso duotam skaičių kūnui, šeimos. Ketvirtoje dalyje nagrinėjamos kongruenčių skaičių kreivės. Įrodoma, kad bent pusė pirminių skaičių p, kurie lieka inertiški cikliniame skaičių kūne K, atitinka kreives 16p^2 = x^4 - y^2, neturinčias netrivialių taškų su koordinatėmis to kūno sveikųjų skaičių žiede. Paskutinėje dalyje iliustruojamas Gauso sveikųjų skaičių skaidymosi daugikliais vienatinumo taikymas įrodant, kad konkreti hiperelipsinė kreivė neturi taškų su sveikosiomis koordinatėmis. / In this document, the author collected his work that ranges through the years 2006-2013. The common theme that occurs in its five separate parts is that of families of algebraic curves defined over the rational numbers with points over a number field or over its ring of integers. In the first part, average number of rational points of small height on hyperelliptic curves of fixed genus is described. In the second part, this result is extended to describing how often, on average, values of homogeneous polynomials at pairs of small coprime integers are values of a given univariate polynomial with integer coefficients. Further, small families of curves that are defined over the rational numbers and do not have points over a given number field are constructed. In the subsequent part, congruent number curves are investigated. It is shown that, given a cyclic number field K, at least half of the prime numbers p that remain inert in K correspond to curves 16p^2 = x^4 - y^2 that do not have nontrivial points over the ring of integers of K. In the last part, a short exposition to a classical technique of showing that a particular curve does not have integral points is given.

In this document, the author collected his work that ranges through the years 2006 - 2013. The common theme that occurs in its five parts is that of families of algebraic curves defined over the rational numbers with points over a number field or over its ring of integers. In the first part, average number of rational points of small height on hyperelliptic curves of fixed genus is described. In the second part, this result is extended to describing how often, on average, values of homogeneous polynomials at pairs of small coprime integers are values of a given univariate polynomial with integer coefficients. Further, small families of curves that are defined over the rational numbers and do not have points over a given number field are constructed. In the subsequent part, congruent number curves are investigated. It is shown that, given a cyclic number field K, at least half of the prime numbers p that remain inert in K correspond to curves 16p^2 = x^4 - y^2 that do not have nontrivial points over the ring of integers of K. In the last part, a short exposition to a classical technique of showing that a particular curve does not have integral points is given. / Disertaciją sudaro darbai, autoriaus atlikti 2006-2013 metais. Šiuos darbus jungianti tema yra algebrinių kreivių, apibrėžtų virš racionaliųjų skaičių, šeimos, einančios per taškus, kurių koordinatės priklauso duotam skaičių kūnui ar jo sveikųjų skaičių žiedui. Pirmoje disertacijos dalyje yra gaunama vidutinio mažo aukščio racionaliųjų taškų kiekio ant fiksuoto žanro hiperelipsinių kreivių asimptotika. Antroje dalyje šis rezultatas išplečiamas, apibūdinant vidutinį homogeninių daugianarių reikšmių taškuose, kurių koordinatės yra mažo aukščio tarpusavyje pirminiai skaičiai, sutampančių su duoto vieno kintamojo daugianario reikšmėmis sveikuosiuose taškuose, skaičių. Trečioje dalyje sukonstruojamos nedidelės kreivių, apibrėžtų virš racionaliųjų skaičių ir išvengiančių taškų, kurių koordinatės priklauso duotam skaičių kūnui, šeimos. Ketvirtoje dalyje nagrinėjamos kongruenčių skaičių kreivės. Įrodoma, kad bent pusė pirminių skaičių p, kurie lieka inertiški cikliniame skaičių kūne K, atitinka kreives 16p^2 = x^4 - y^2, neturinčias netrivialių taškų su koordinatėmis to kūno sveikųjų skaičių žiede. Paskutinėje dalyje iliustruojamas Gauso sveikųjų skaičių skaidymosi daugikliais vienatinumo taikymas įrodant, kad konkreti hiperelipsinė kreivė neturi taškų su sveikosiomis koordinatėmis.

The objective of this thesis was to determine the association of leg length (LL), a marker of early childhood conditions, with metabolic abnormalities underlying type 2 diabetes. Utilizing data from a population at-risk for diabetes, the associations of LL with i) insulin resistance (IR) and beta-cell dysfunction and ii) a continuous metabolic syndrome risk score (MetScore) were analyzed. Results showed that shorter LL was associated with IR and beta-cell dysfunction, and that the combination of short legs and large waist (a marker of adult obesogenic conditions) was associated with the greatest IR. Height, a marker of overall childhood conditions, was found to be inversely associated with the MetScore. Therefore, both adverse childhood conditions and early-late life mismatched conditions may increase the risk for diabetes through differing pathways. Improving childhood conditions (i.e. nutritionally or economically) may be an important strategy to prevent diabetes.

The objective of this thesis was to determine the association of leg length (LL), a marker of early childhood conditions, with metabolic abnormalities underlying type 2 diabetes. Utilizing data from a population at-risk for diabetes, the associations of LL with i) insulin resistance (IR) and beta-cell dysfunction and ii) a continuous metabolic syndrome risk score (MetScore) were analyzed. Results showed that shorter LL was associated with IR and beta-cell dysfunction, and that the combination of short legs and large waist (a marker of adult obesogenic conditions) was associated with the greatest IR. Height, a marker of overall childhood conditions, was found to be inversely associated with the MetScore. Therefore, both adverse childhood conditions and early-late life mismatched conditions may increase the risk for diabetes through differing pathways. Improving childhood conditions (i.e. nutritionally or economically) may be an important strategy to prevent diabetes.

Background: Obesity-related diseases are arising as a major problem among children. inflammation has recently been identified to play an important role in the relationship between obesity.- as well as stunting-related diseases. Objectives: The aim of this study was to assess the association between serum tumour necrosis factor-alpha (TNF-α), interleukin-6 (IL-6) and C-reactive protein (CRP) concentrations and a variety of cardiometabolic and anthropometric indices of children in a township outside Potchefstroom, South Africa. Methods: Blood samples of 115 girls and 78 boys (mean age 15.6 ± 1.35) in the Physical Activity in the Young (PLAY) study were cross-sectionally analysed. Trained fieldworkers collected the demographic, Tanner growth stage and habitual physical activity information. Physiologists measured the children’s blood pressure. Anthropometric measurements were taken by. trained post-graduate students with level 1 or 2 qualifications in anthropometrics. A standard test battery was administered by trained postgraduate students in Human Movement Science to assess muscular strength. flexibility and endurance of the children. Blood samples were collected, centrifuged and stored frozen until further analyses. Results: Stunted girls had a significantly higher serum TNF-α concentration than the non-stunted girls (p=0.03). The factor analyses showed that the inflammatory. status clustered with the height for age-z-scores (HAZ) scores and the waist-hip-ratio (WHR). The HAZ-score of the over-fat boys (- 1.46) was significantly smaller than the lean boys (- 1.14, p=0.0 1). whereas the over-fat girls had a trend for a smaller HAZ-score (-1.07) than the lean girls (-0.89). No significant differences were found between the over-fat and the lean children-s inflammatory status. TNF-α and CRP levels tended to be higher in the over-fat children than in lean children. The girls' scrum IL-6 and CRP concentrations correlated significantly with their body mass index (BMI) and WHR (p<0.05 )and their TNF-α and IL-6 concentrations correlated significantly with their WHR (p<0.01 and p<0.05, respectively). Conclusion: In comparison to the non-stunted girls, stunted girls had a statistically significantly higher TNF-α concentration. Unusual fat distribution that is found in over-fat and stunted children may be associated with low-grade inflammation in children. More research is needed on these associations with markers of inflammation in a long-term longitudinal study. / Thesis (M.Sc. (Nutrition))--North-West University, Potchefstroom Campus, 2007.