The ecology of the Hecate Strait population of butter sole (isopsetta isolepis (Lockington)) is studied to facilitate a better understanding of the fluctuations in abundance and to permit a more optimal utilisation of the stock. The reaction of the population to varying degrees of exploitation and natural mortality rates is analysed for steady and fluctuating recruitment using Ricker's model. The magnitude of error inherent in the models used for the theoretical studies of exploited populations is also examined by subjecting a hypothetical population in a steady state to various mortality and growth rates. This is done both for a continuous fishery and after appropriate modifications in Beverton's model for a seasonal fishery as well. Butter sole population spawning in Skidegate Inlet is confined to the Hecate Strait bank. The species show depth stratification, the young ones being found in shallower waters. Although the population exhibits seasonal movements between shallow and deeper waters, a north-south migration is limited mostly to the spawning population. Sexual differences in the time of onset of maturity and migratory pattern are also observed. No association between butter sole and related species of flatfish is noted. A study of the discreteness of the Hecate Strait population suggests that this area is inhabited by a single self-contained stock. Growth studies of butter sole indicate that there are annual, seasonal, regional and sexual differences. The average growth of butter sole belonging to a strong year class seems to be influenced by intra-specific competition, even though a tendency in later years to compensate for the initial difference in growth is also exhibited. The survival rate of butter sole above six years is relatively low. A comparison of the relative abundance of young butter sole taken in the 1952-1954 samples from along the Graham Island coast with the success and age composition of the fishery which existed from 1958-1960 when these year classes became fully exploitable, indicates that fluctuations in the butter sole population are mainly due to variations in early survival rate. Yield isopleths and equilibrium yield curves indicate that the maximum equilibrium yield will be obtained when the age of exploitation is 4.83 years or greater only when F is higher than 1.8. The fishing mortality operates for only a short time each year while natural mortality is continuous, and a change in the latter therefore influences the yield and biomass more than a similar change in the fishing mortality. A higher increase in the natural mortality with age results, under fluctuating recruitment, in greater deviations in yield and biomass. As the older age groups now contribute less to the population, the effects of fluctuations in abundance of the entering year class on the stock become more pronounced. There is little difference in the yield per recruit (Yw/R) estimates from Beverton's or Ricker's model for a hypothetical population under various situations, provided Ricker's model makes use of an exponential average of the biomass during each time period. The slight difference observed is due to the manner of depicting the growth pattern. Due to seasonal differences in growth rate, Yw/R estimate from Beverton's model, need not be more accurate than from Ricker's model. A heavier exploitation of the butter sole population is warranted on the basis of the theoretical studies, provided the heavier exploitation does not decrease the number of fertilized eggs by over-exploiting the males that are more abundant on the spawning grounds. Due to sexual differences in the population parameters and the migratory and recruitment patterns, the two sexes may be treated in further studies, as a special case of two competing populations exploited simultaneously. / Science, Faculty of / Zoology, Department of / Graduate

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Thesis (M.S.)--Oregon State University, 1992. / Typescript (photocopy). Includes bibliographical references (leaves 78-88). Also available on the World Wide Web.

ix, 77 leaves : ill. ; 29 cm Notes Typescript Thesis (M.S.)--University of Oregon, 1986 Includes vita and abstract Bibliography: leaves 73-77 Another copy on microfilm is located in Archives

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Ultra High Molecular Weight Polyethylene (UHMWPE) has been used as a ski sole material for many years due to its good tribological properties, good wear resistance and low friction coefficient. Recent studies have showed improved performance on wear rate and hydrophobicity with nanoparticle reinforced UHMWPE. In this study, different kinds of nano-composite UHMWPE’s were tested on snow to investigate if they are suitable as a ski sole material and to find the type of nano-composite UHMWPE that has the greatest potential. Further, the mechanisms of hydrophobicity and its influence on the friction level were examined. The friction coefficient was measured in a ski test rig and simple demonstrations under a microscope were made to simulate how water is dragged along the ski sole in contact with wet snow. Mechanical properties were measured with a CSM Nanoindentation Instrument and surface topography was examined in a Wyko Optical Profiler. The cross-linked UHMWPE material showed the lowest friction coefficient on snow. The hydrophobic demonstrations, together with the ski test results, questions the suggestion that high hydrophobicity enhances the ski glide. Nanoindentation was proved to give valuable data for mechanical properties, but it should be questioned whether it is a good technique for comparing different nano-composite UHMWPE materials. The ski tests show the importance of the characteristics of snow.

Thesis (M.S.)--Oregon State University, 2008. / Printout. Includes bibliographical references (leaves 57-62). Also available on the World Wide Web.

Garnet-bearing gneisses from the vicinity of Passo del Sole, Central Swiss Alps, have undergone a complex history of metamorphism and deformation that has imbued them with unique compositional and textural variations. Complex, concentric zoning patterns in garnet may be correlated between porphyroblasts on the scale of a hand sample; however, the character of the Ca, Mn, and Y zoning patterns in garnet vary within single layers on the meter-scale. Within a hand sample, individual compositional zones can be correlated from crystal to crystal on the basis of chemical similarities (e.g., intricate yet identical variations in calcium concentration; equivalent manganese concentrations at zone boundaries) and textural similarities (e.g., initiation of inclusiontrail curvature). These relationships allow the identification of individual compositional zones as time markers during garnet growth. Detailed examination of garnet growth zoning patterns, in combination with measurements of inclusion-trail curvature within garnet porphyroblasts and detailed thermodynamic models of the garnet growth history in selected samples, together with an assumed heating rate associated with Alpine metamorphism, allows quantification of strain-rates during prograde amphibolite-facies metamorphism along the northern margin of the Lucomagno nappe. Constraints on the nucleation and timing of garnet growth and garnet growth rate mechanisms permit further insight into the relationship between strainrate and metamorphism at Passo del Sole than had previously been possible with this method: variations in strain-rate magnitude of over a factor of ten (10⁻¹⁴ - 10⁻¹³ s⁻¹) are observed, which correlate with core-to-rim changes in compositional zoning. The source of the incredible diversity of compositional zoning patterns in garnet is hypothesized to be open-system infiltration of ephemeral, channelized Ca- or Mn-rich fluids derived from magmatic sources or equilibrated with metamorphic rocks deeper in the section. Stages of garnet growth associated with increased strain rates are also correlated with the high-Ca or high-Mn zones within the garnet porphyroblasts, presumably as the result of strain softening associated with the passage of these fluids. In-situ oxygen isotope analysis using SIMS demonstrates that the changes in majorelement zoning patterns correlate with small shifts in the isotopic composition of garnet. / text

Flippfloppsandaler förknippas med sol och ledighet i Sverige. Men i många andra länder är det en sko som används dagligen, året om. Det sägs vara världens mest sålda sko. Den är billig och åker lätt på foten men den åker lika snabbt av. Vid kraftigt regn riskerar avställda floppfloppsandaler att flyta iväg från sina ägare. De åker längs vattendrag och inte sällan ut i havet tillsammans med en massa annat skräp. För personen som blev av med sandalerna kanske det inte gör så mycket, det går ju att köpa ett par nya i närmsta kiosk. Men faktum är att de är en del av ett stort problem. Plaster i haven bryts inte ner biologiskt utan blir mindre och mindre bitar av solen. Plastbitarna äts av fiskar och fåglar som tar skada. Plast drar också till sig gifter som PCB och DDT. När människor äter fisk som fått i sig plast vandrar gifterna uppåt i näringskedjan. Efter att länge färdats på havet kanske flippfloppsandalen spolas upp på land. Och kanske hittas den då av företaget och organisationen Ocean Sole i Kenya. De plockar tappade flippfloppsandaler i slumområden och längs Kenyas kust. Vissa sandaler har flutit dit ända från Asien. Flippfloppsandalerna sorteras, tvättas, limmas ihop, skärs till och slipas av hantverkare i Nairobi därefter. De blir till allt från skulpturer till smycken som säljs världen över. Ocean Sole återvinner ett ton flippfloppsandaler i veckan och det ser inte ut som att de någonsin kommer få slut på material. Flippfloppsandalen är i sig en symbol för slit- och slängsamhället men bär också ett meddelande från havet om att havet håller på att bli världens soptipp. Radioreportaget belyser därmed ett stort problem genom en enskild produkts livscykel.