11 |
The anatomy and biomechanical properties of bifurcations in hazel (Corylus avellana L.)Slater, Duncan Royd January 2016 (has links)
The anatomy of bifurcations in trees requires further scientific investigation as the current anatomical model for them is logically flawed. The provision of a better model will assist in scientific studies of woody plants, the risk assessment of junctions in mature trees and provide bio-inspiration for Y-shaped joints in composite materials. In this study, the xylem formed in the central axis of a hazel (Corylus avellana L.) bifurcation is shown to provide a disproportionately greater amount of its tensile strength. CT scanning identified that this centrally-placed xylem was 28.1% denser, with 63% less vessels formed in this tissue, such vessels being 50.5% of the diameter and 32.5% of the length of those formed in adjacent stem tissues. The wood grain pattern at the bifurcation apices were 22 times more tortuous, forming interlocking patterns that acted to resist tensile forces by requiring the extraction or breaking of wood fibres along their length (the axial tensile strength of wood). Subsequent tests confirmed that this conferred more than 100% additional tensile strength to these specialised xylem tissues. These findings provided the basis of a novel anatomical model for bifurcations in woody plants. Further to this, the effects of several factors upon junction strength and biomechanical behaviour were assessed in bifurcations of hazel, identifying the weakening effect of bark inclusions and three types of artificial modification as well as differences in wind-induced movement between bifurcation types. This study concludes that further investigations of bifurcations in a wider range of woody plants and observations of the developmental stages of the interlocking wood grain patterns found at bifurcations would usefully add to existing knowledge.
|
12 |
Investigating the influence of vehicular traffic on a major trunk road on rural air qualityObara, Paul Goodluck January 2012 (has links)
Traffic population in the UK has grown by 27% in 2002 and predicted to continue to an estimated 38% in 2016 and up to 60% by 2031. This means vehicular emissions from road transport may account for higher proportion of total emissions of pollutants resulting in air pollution with its attendant consequences. Although poor air quality concerns has often been linked to urban areas, many rural areas apparently have locations where air quality objectives may be threatened especially in the wake of increasing vehicular population. Thus, this elicits the necessity to investigate the relationship between vehicular emissions and air quality. This study investigated the influence of vehicular traffic on a major trunk road on rural air quality through continuous measurements of nitrogen dioxide, sulphur dioxide and hydrocarbon between June 2008 and April 2010 along a major trunk road in a catalogued rural environment in the UK. Collection and analysis of pollutants was by Dräger short-term tubes and Dräger passive diffusion tube techniques. Throughout the sampling period, concentrations of sulphur dioxide were not detected using the short-term tube technique but were detected by the passive diffusion tubes. The study found that variations in mean concentrations of the pollutants were synonymous with traffic frequency and were influenced by meteorological conditions especially wind speed, temperature and relative humidity. Results observed concentration decline trend with increasing distance and showed maximum concentrations during winter, mainly in areas of close proximity to anthropogenic source, and minimum in summer. Values between winter year 1 and winter year 2 monitoring campaigns showed significant difference (P<0.05 and R=0.91) as was in summer year 1 and year 2 (P<0.05 and R=0.94), spring year 1 and year 2 (P<0.05 and R=0.84) and autumn year 1 and year 2 (P<0.05 and R=0.79). When compared with the guidance limits, NO2 Page ii showed exceededance at roadside and 50 m, and at some sample sites, up to 100 m from the road. Conversely, SO2 did not show any exceedance but statistical analyses was mostly significant between concentrations and distance at p≤0.05, suggesting the variability of pollutants, as well as the influence of distance on their temporal and spatial distribution. Results also show that pollutants correlated very well with daily traffic population with strong positive r2 and R-values. Similarly, the study considered the application of hazel leave (Corylus avellana) and ryegrass (Lolium perenne) vegetation samples in monitoring rural air quality. Both samples were collected in different seasons and distances (5m, 50m, and 100m) from the A49 trunk road at four rural sites characterised with diverse traffic densities and anthropogenic activities. The aim was to determine the elemental content and trends within the samples and to investigate the influence of distance from the road, height from ground level, and sampling season on the elemental levels. The levels of Al, As, Ba, Ca, Si, Mg, S, Cd, Cr, Na, Ni, Sb, Se, Sn, Mo, Mn, C, K, P, Cl, Ti, Fe, Zn, and Pb were determined using X-ray fluorescence (XRF), inductively coupled plasma-mass spectrometer (ICP-MS), and Scanning Electron Microscopy-Energy Dispersive X-ray spectrometer (SEM-EDX). Results show that despite the traffic differentials between the sampling sites, the pollution level of heavy metals were generally low in all sampling site and concentrations of Cr, Cu, Ni, Pb, and Ti exhibited inverse relationship with distance, decreasing in levels with increasing distance from the trunk road. Although root uptake from the soil is a potential source of heavy metals, geochemistry research of the study area did not show any evidence that proves any major heavy metals deposit concerns in the soil. It is therefore possible that heavy metal emissions were deposited in a form that was not readily available for root uptake, thereby narrowing the presence of heavy metal pollutants to other potential Page iii sources. However, this study found high level of heavy metals at the roadside measurements in the order of Zn (0.703 ppm) > Ti (0.346 ppm) > Cr (0.111 ppm) > Cu (0.106 ppm) > Pb (0.026 ppm) > Ni (0.025 ppm). They were found in different magnitudes higher than their respective levels at 50 and 100 m from the trunk road and therefore tend to support traffic origin. Findings from this study show that heavy metals exhibited different degree of correlation between individual elements, ranging from very strong positive to weak, as well as negative correlations. Statistical analyses show that the elements predominantly exhibited statistically significant differences between elements and between distances from the road. Overall, findings from this study demonstrate that both vegetation species prove to be successfully useful in determining the pollution status and trends of traffic-related heavy metals.
|
13 |
Jerubės (Bonasa bonasia) buveinių pasirinkimo ypatumai Asvejos regioniniame parke / Peculiarities of habitat selection by Hazel Grouse (Bonasa bonasia) in the forests of Asveja Regional ParkMatulionytė, Kristina 29 June 2009 (has links)
Tyrimai atlikti 2008 m. Asvejos regioninio parko miškuose. Tyrimų metu užregistruota 18 jerubių (Bonasa Bonasia L). Analizuota šios rūšies biologijos, ekologijos ypatumai labiausiai įtakojantys buveinių pasirinkimą. Jerubės veisimosi metu dažniau pasirenka sklypus, kuriuose pirmąjį medžių ardą formuoja paprastoji pušis (Pinus sylvestris L.), beržas (Betula), paprastoji eglė (Picea abies L). Reikšmingos įtakos medynų amžius, lajų susiglaudimo laipsnis, pomiškio tankumas jerubės buveinių pasirinkimui nenustatyta. Jerubės dažniausiai pasirinko medynus augančius derlingesnėse augavietėse. Nustatyta, kad jerubės dažniau aptinkamos medynuose su vyraujančiu paprastojo lazdyno, paprastosios ievos bei dalinai sausmedžio traku, todėl šios medyno struktūrinės dalies įtaka jerubės buveinių pasirinkimui laikytina reikšminga. / The Researchs was done in forest of Asveja regional park in 2008. Was registrated 18 Bonasa Bonasia L. during the research. This sort biological and ecological peculiarity mostly influencing residence selection was analyzed. Grouses in breeding season mostly picks plots, where first trees dissensions forms Pinus sylvestris L., Betula, Picea abies L. Significant, forests age, folding degree, underwood thickness, influence of grouses residense selection wasn‘t found. Grouses mostly picked forests which grew in productive areas. Were identyfied, that grouses mostly were found in forest with dominent ordinary nutwood, ordinary eva and partly honeysuckle glade, thats why these forests structural part has significant influence on grouses residence selection.
|
14 |
Hazel Dormouse ecology and conservation in woodlandsGoodwin, Cecily Erica Diana January 2018 (has links)
The extent and quality of forested habitats have changed across Europe and as a result many forest species have suffered declines and range contractions. European legislation has been introduced to conserve those species that have been negatively impacted by widespread land-use changes. In order to assess the needs of declining species and the efficacy of these protective measures, the effects of habitat type, configuration and management on individuals and populations needs to be understood. In this thesis, I have investigated patterns and drivers of variation in the status of populations of hazel dormouse Muscardinus avellanarius in the United Kingdom. I have assessed the effects of variation in habitat on hazel dormice at multiple spatial scales, and related this to woodland management.
|
15 |
Structure, function, and analysis of Coleoptera and Heteroptera assemblages on two species of hazelnut in OregonWetherill, Karen R. 26 January 2000 (has links)
The European hazelnut, Corylus avellana L., was imported into the U.S. in the
late 1800's and is now grown throughout the Willamette Valley in Oregon. A native
species of hazelnut, C. cornuta Marshall, is a common shrub found in forested areas of
the Pacific Northwest. Foliage of both C. avellana and C. cornuta was sampled using
beating sheets. The objectives of the study were as follows: 1. To compile a complete list
of the Coleoptera and Heteroptera fauna of both species of hazelnut. 2. To determine the
amount of overlap across host plants. 3. To measure arthropod abundance and species
diversity within functional groups across a forest-edge-orchard gradient. 4. To use
ordination techniques to determine where peak abundance of individual taxa occur along
the forest-edge-orchard gradient. One hundred and thirty-two species of Coleoptera and
forty-nine species of Heteroptera were identified on Hazelnut foliage. The most
abundant Heteroptera in the orchards studied is a newly introduced mirid predator,
Malacocoris chlorizans (Panzer). There is a great deal of overlap between the two
hazelnut species. Most differences are attributed to rare species. Diversity and
abundance of predaceous Coleoptera and Heteroptera were severely hindered by IPM
management practices, involving insecticide usage, within the orchards. However, the
organic orchards retained high levels of diversity and abundance of predaceous
Coleoptera and Heteroptera in the centers of the orchards. The organic orchards had
higher diversity of phytophagous Coleoptera and Heteroptera as compared to IPM
orchards, but the abundance of those insects was not different between the IPM and
organic orchards. The ordinations of the Coloeptera data show that the peak abundances
of individual species often shift along the forest-edge-orchard gradient over time and that
the organic orchards retain peak abundances of predaceous Coleoptera even in late
season. The ordinations of the Heteroptera data show that several mirid predators are at
their peak abundances within the orchards of both IPM and organic orchards. / Graduation date: 2000
|
16 |
Subversive voices a study of text and performance in the interpretation and realisation of experimental poetry /Manning, Joanne Melissa. January 2005 (has links)
Thesis (PhD)--Macquarie University, Division of Humanities, Department of English, 2005. / "March 2002". Bibliography: p. 324-344.
|
17 |
Hassel (Corylus avellana) som indikator på markanvändningshistorikWallstedt, Lennart January 2015 (has links)
Hazel (Corylus avellana L.) is a common feature of meadows and pastures where it can grow in large populations and become very old. Is it possible to use the size of hazel stools for age determination and is it possible to use the size distribution of a population to provide information about how the land has been used? Hazel populations on ground where the lake-water level had been lowered, has been studied to validate an already developed growth model of hazel clones. Different hazel populations, on wooded meadows affected by mowing or grazing or overgrown meadows, were studied to evaluate the method utilizing hazel as land use indicator. The growth model was used to compare the size distributions of hazel populations with historical periods, which has been important for changes in agriculture or demography. The results show that the current growth model needs to be refined, but the method itself with a growth model based on the circumference of hazel bushes seems feasible. Additional studies about the influence of, for example, soils of different fertility are needed. The results also show that the size distribution in a population depends on how much meadows have been affected by mowing or grazing and that areas with similar land use have similar size distribution. Finally, some examples are reported about how a growth model can be used to compare historical periods of changes in agriculture, for example reduced livestock, with variations of the size distribution in a hazel population.
|
18 |
Jerubės (Tetrastes bonasia) populiacijų genetinės struktūros įvertinimas lietuvoje, naudojant mikrosatelitų molekulinius žymenis / Evaluation of genetic variation in a Hazel Grouse (Tetrastes bonasia) population in Lithuania using microsatellite markersTomaitė, Gintarė 13 August 2012 (has links)
Šiame darbe buvo tiriamas Lietuvoje gyvenančių jerubių genetinis variabilumas panaudojant mikrosatelitinių pradmenų analizės metodus. Pavyzdžiai buvo surinkti iš Rietavo savivaldybėje, Ukmergės, Trakų, Vilniaus, Šakių ir Telšių rajonuose esančių miškų. DNR buvo išskiriama iš neinvaziniu būdu surinktų pavyzdžių, iškritusių plunksnų bei surinktų ekskrementų. Kadangi specialių mikrosatelitinių pradmenų jerubių rūšiai dar nėra sukurta, šiame darbe buvo panaudotos trys žvyrėms (Lagopus lagopus) specifiški mikrosatelitinių lokusų pagausinimui skirti pradmenys. Buvo apskaičiuoti alelių, genotipų ir heterozigotiškumo dažniai, ir individai iš Ukmergės MU pasižymėjo žemu alelių dažniu ir aukštu homozigotų dažniu. Mitochondrinės DNR analizė parodė, kad tarp 12 Lietuvos populiacijai priklausančių jerubių sekų, net 8 buvo skirtingos ir dėl to priskirtinos 8 skirtingiems haplotipais. Mitochondrinės DNR sekų filogenetiniai ryšiai parodė, kad Lietuvos jerubių populiacijoje aptikti haplotipai formuoja dvi filogenetiškai tolimas šakas, tuo tarpu Lenkijos haplotipų įvairovė gerokai didesnė. Tikėtina, kad šiuos skirtumus labiausiai įtakoja nevienodi lyginamų imčių dydžiai. / Non-invasively collected samples of feathers and faeces of Hazel Grouse (Tetrastes bonasia) were collected in different parts of Lithuania and covered several local populations of Rietavas, Ukmergė, Trakai, Vilnius, Šakiai and Telšiai districts. Three primer pairs of microsatellite loci, designed for taxonomically related Red Grouse (Lagopus lagopus scoticus), were used to verify their suitability for evaluation of genetic structure. Allele and genotype frequencies as well as heterozygosity were calculated and individuals from Ukmergė showed low frequency of allele, and high in homozigosity. Mitochondrial DNA analysis showed that in 12 sequences from Lithuanian population, 8 of them were different and could be assigned to 8 different haplotypes. Neighbour joining tree showed that haplotypes in Lithuanian population forms two branches with high distance. While variability of Poland haplotypes, obtained from Gene Bank was bigger. That could be affected by different compared samples sizes.
|
19 |
Anna May Wong and Hazel Ying Lee--Two Second Generation Chinese American Women in World War IISui, Qianyu, Sui, Qianyu January 2012 (has links)
Applying a historical approach which contextualizes ethnic and gender perspectives, this thesis investigates the obstacles that second-generation Chinese American women encountered as they moved into the public sphere. This included sexual restraints at home and racial harassment outside. This study examines, as well, the opportunities that stimulated these women to break from their confinements.
Anna May Wong and Hazel Ying Lee will serve as two role models among this second generation of women who successfully combined their cultural heritage with their education in the U.S. Their contributions inspired a whole generation of young bi-cultural women of their time. I will argue that, although the second generation had gone through cultural acculturation and resistance toward American mainstream culture, they constructed their new Chinese American identity during World War II through a synthesis of their contribution to the gender relations and ethnic identification in nationalist project.
|
20 |
Movement, growth and mortality of brook trout within the Hazel River, Shenandoah National ParkBryan, Roger D. 10 November 2009 (has links)
Density and standing stock of brook trout within the Hazel River, Shenandoah National Park, declined sharply between 1982 and 1989. Most of the reduction occurred within the middle and lower reaches, where density of brook trout declined 66% and 920/0, respectively. This study characterized the movement, growth, and mortality of the Hazel River brook trout population in 1989-1990 and examined the role of these phenomena in the recovery of that population. Physical habitat appeared excellent throughout the stream, with adequate pools, cover, and spawning substrate in all sections. Results from visible implant tag recoveries established that the majority (60%) of adult and yearling trout were sedentary during the one year study period. Brook trout exhibiting movement tended to move upstream during the fall over relatively short distances ( < 250 m). Movements of up to 700 m (up- and downstream) were observed in less than 5% of post-juvenile trout. Young-of-the-year (YOY) trout moved more frequently than other age groups and tended to move downstream; they are probably the primary vehicle of downstream recolonization. Growth and condition of Hazel River brook trout were typical of other streams within Shenandoah National Park. Poor growth occurred during the summer months, which is typical of southeast stream trout populations. Generally, growth was higher in areas where density was lowest. Estimated mortality over summer was highest (400/0) for yearling and adult trout within the upper reaches. Despite closure of the Hazel River to angling for two years, its brook trout population remained depressed in 1989. The study demonstrated that recovery of depleted trout stocks through intrastream migration may be slow. Reasons for the continued depression of the brook trout population in the Hazel River may include predation by American eels, illegal angIer harvest, the sedentary nature of stream-dwelling trout, or a combination of these factors / Master of Science
|
Page generated in 0.0441 seconds