Im Rahmen der vorliegenden Arbeit wurden kapselumhüllte Hüftgelenkmodelle mit 22 – 44 mm Durchmesser durch Hebelwirkung luxiert, wobei die wirkende Kraft, die resultierende Dislokation und der intraartikuläre Absolutdruck kontinuierlich gemessen wurden. Parallel dazu wurde die technische Range of Motion bis zum Impingement und bis zur Luxation bestimmt. Die durchgeführten Hebelversuche ergaben bei Zunahme des Kopfdurchmessers eine erhebliche Zunahme des Luxationswiderstandes der untersuchten Gelenkmodelle. Im Gegensatz dazu ergab die Messung der technischen Range of Motion bei größerem Gelenkdurchmesser einen geringen Zuwachs, dessen praktische Wirksamkeit durch existierende Literatur auf Grund von Knochen-Knochen-Impingement in Zweifel gezogen wird (Burroughs et al. 2005). Die Hypothese ist somit anzunehmen. Die starke Zunahme des Luxationswiderstandes und die gering erweiterte techROM sprechen neben anderen Argumenten dafür, dass die permanente hüftstabilisierende Wirkung des atmosphärischen Druckes, die auch als Weber-Effekt bezeichnet werden kann, die Hauptursache für die deutlich verminderte Luxationsneigung größerer Köpfe nach hüftendoprothetischen Eingriffen darstellt. Daraus können folgende Konsequenzen für die Hüftendoprothetik abgeleitet werden: 1. Die Schonung und Rekonstruktion der Gelenkkapsel ist eine wichtige Voraussetzung für die Wirksamkeit des Weber-Effektes. Zahlreiche Studien belegen, dass durch die Kapselrekonstruktion die Anzahl der von Luxationen betroffenen Patienten um 90 % gesenkt werden kann (Pellicci et al. 1998; Bottner und Pellicci 2006; Prietzel et al. 2014), weshalb die Kapselrekonstruktion zu empfehlen ist. 2. Gelenkköpfe mit größerem Durchmesser besitzen in Folge des Weber-Effektes eine wesentlich größere Gelenkstabilität bzw. einen höheren Luxationswiderstand. Daraus resultiert offensichtlich die klinisch nachgewiesene wesentlich geringere Luxationsra-te (Bistolfi et al. 2011; Howie et al. 2012, Zajonz et al. 2015). Gegenwärtige Nachteile größerer Köpfe wie höherer Abrieb und vermehrte Belastung von Pfannenveranke-rung und Konus müssen jedoch berücksichtigt werden. Der Einsatz größerer Gelenk-köpfe ist zukünftig in der Hüftendoprothetik anzustreben. Gegenwärtig ist bei normalem Luxationsrisiko und somit bei primären HTEP-Implantationen der Einsatz von Gelenkköpfen bis 36 mm Durchmesser vertretbar. Bei erhöhtem Luxationsrisiko (z. B. bei bestimmten HTEP-Revisionen) sind dagegen 40-mm- und 44-mm-Köpfe gerechtfertigt, soweit diese in Abhängigkeit vom Pfannendurchmesser realisierbar sind (Zajonz et al. 2015). 3. Der Einsatz einer intrakapsulären Redondrainage beschleunigt durch die Eliminierung eingedrungener Luft und durch die Minimierung des postoperativen Hämatoseroms die Restitution physiologischer Gelenkverhältnisse. Dies ist gleichfalls eine wichtige Voraussetzung für die Wirksamkeit des Weber-Effektes und daher zu empfehlen (Prietzel et al. 2007).

[Truncated abstract] First metatarsophalangeal joint (MTPJ1) motion is an important factor in normal weight transference during walking. Disruptions to normal range can influence joints both proximal and distal to the MTPJ1, potentially leading to pain and dysfunction. Whilst the MTPJ1 has been investigated significantly, the numerous methodologies described to quantify range of motion can be questioned and makes comparisons difficult. Range of MTPJ1 motion is commonly assessed in a clinical setting to determine pathology as well as to make decisions on appropriate intervention. The anatomical and biomechanical influence of tendo Achilles load and MTPJ1 motion has been well described; however few studies measuring MTPJ1 range control for Achilles load or describe ankle joint positioning. Further to this the effects of reducing tendo Achilles stiffness on MTPJ1 extensions has yet to be investigated. The purpose of this study was to describe a technique to quantify passive MTPJ1 extension and to determine the influence of ankle joint position on joint range. Secondly the effect of calf muscle stretching on MTPJ1 range was also investigated. The information gathered will assist both research and clinical protocols for quantifying MTPJ1 range, and provide a greater understanding of the anatomic and biomechanical relationship between tendo Achilles load and MTPJ1 extension. In order to fulfil the purposes of the study it was necessary to establish a reliable methodology to quantify non weight bearing MTPJ1 extension. Reliability testing was undertaken in three parts. '...' The results demonstrated a statistically significant increase in joint range immediately following a one minute stretch for variables ankle joint range of motion as well as MTPJ1 extension for ankle joint plantar flexed at 10 Newton's and ankle joint neutral and plantar flexed at 30 Newtons. No significant differences were noted in ankle or MTPJ1 range of motion in either the control group on immediate re-testing, or in both groups after a one week stretch program. The findings of this study support those documented in the literature pertaining to the ankle joint position, tendo Achilles load and plantar fascial stiffness to MTPJ1 range of motion. Increased stiffness at the MTPJ1 was noted dependant on ankle joint position from ankle joint plantar flexion through to ankle joint dorsiflexion. This appears most likely due to increases in tendo Achilles load and subsequent forces transmitted to the plantar aponeurosis. The present study also demonstrated a trend towards increased joint extensibility and limb dominance. The study also supports previous literature into gender differences and joint extensibility, with a positive trend towards increased MTPJ1 range evident in the female subjects tested. The study also demonstrated the immediate effect of calf muscle stretching on ankle and MTPJ1 range of motion. It remains however unclear as to the exact mechanisms involved in producing increased joint range be it reflex inhibition or actual changes to the viscoelastic properties of the soft tissues. Despite this, no changes were evident following a one week stretching program, which supports previous literature describing a short lag time before soft tissues revert to baseline length properties following a single stretch session.

In this study, biological and chemical characteristics were determined for two high-elevation meadow-to-forest transitions located in the Central Oregon Cascades. The chloroform fumigation incubation method (CFIM) was used to determine microbial biomass C(MBC) and the N flush due to fumigation (NF), and meadow values were compared to forest values for each. Meadow and forest MBC values were also compared for estimates of MBC determined with microscopy and these values were compared to CFIM estimates. Net N mineralization and C mineralization were determined for an 85-d incubation period and used as a measure of labile C and N. Microbial biomass C and NF were then compared to these labile pools in order to investigate the relationship between the amount of each nutrient stored in biomass and the magnitude of the respective labile nutrient pool for each. Long-term and short-term net N mineralization rates and C/N ratios were also compared for meadow and forest soils, and the relationship between these two characteristics was examined. In general, microbial biomass estimates made with the CFIM method did not show any significant differences between meadow and forest soils. Mean MBC for both sites as determined by CFIM was estimated to be 369 and 406 μg C g⁻¹ soil in meadow and forest soils, respectively. Mean NF was estimated to be 37 and 56 μg N g⁻¹ soil in meadow and forest soils, respectively. MBC estimates made using microscopy showed biomass C to be greater in the forest than in the meadow. Mean MBC as determined by microscopy was estimated to be 529 and 1846 μg C g⁻¹ soil in meadow and forest soils, respectively. The NF measured as a percentage of the net N mineralized over 85 d was significantly greater in the forest than in the meadow soils, but was a substantial percentage in both. The means of these values were 30 and 166% in meadow and forest soils, respectively. This led to the conclusion that biomass N may be a very important pool of stored labile N in this ecosystem. Net N mineralization rates were almost always greater in the meadow than in the forest soils. Net N mineralization for the 10-d incubations averaged 21 μg N g⁻¹ soil in the meadow and 8 μg N g⁻¹ soil in the forest Rates for long-term N mineralization averaged 126 μg N g⁻¹ soil in the meadow and 52 μg N g⁻¹ soil in the forest. Net N mineralization rates were correlated with C/N ratios for both short-term and long-term incubations. / Graduation date: 2002

Small herds of cows were observed and spatially mapped over continuous twenty-four hour periods. Treatments were implemented that investigated the effect of water site and supplementation on animal distribution patterns. A series of six observation periods constituted each observation series. Observation series were repeated winter (January) and summer (July) for two years. Forage conditions varied considerably between years and seasons. Three regression models for different periods related forage variables to animal use with R�� values ranging from 0.51 to 0.77. A spatial point analysis, Ripley's K, also discerned differences in spatial point arrangements related to differences in forage and season. It detected and quantified changes caused by locating a high-protein supplement in the pasture. Swale sites and slopes of less than 10 percent were preferred for grazing in all seasons. Water sources and shade trees were distribution focal points for three observation series. In the winter of 1998, animals spent more time on warmer sites. We recorded more cow activity and movement at night than other researchers. Resting areas had aspect and elevation attributes that relate to temperature regulation. Animal positions were analyzed to determine cattle subgroups. Forage availability and thermoregulatory needs influenced the distance between associated members. Social dominance and subgroup membership were closely related to the age of individual animals. A geographic information system based technique called multi-criteria evaluation was used to develop temporal/spatial models predicting cattle distribution across the landscape. Summer models worked better than winter models because water sources and shade sites were more consistent as focal points for cattle activities. / Graduation date: 2002

This study assessed how logging-access roads may have contributed to observed historical increases in peak discharges associated with small and large logged basins in the western Cascades of Oregon. The study was conducted on the Lookout Creek (62km��) and the upper Blue River (118km��) basins. Potential road effects on hydrology were examined using a combination of field surveys and spatial modeling with a geographic information system (GIS). Road networks were similar in both basins with respect to hillslope position, orientation, and stream crossings, but roads in Blue River were constructed one or two decades later than roads in Lookout Creek. A total of 20% (62 km) of the road length was sampled to assess routing of surface flow, using 31 2-km transects stratified by decade of construction and hillslope position. Along each transect, ditches and culvert outlets were examined and this information used to predict the probable routing of water to (1) existing stream channels, (2) newly eroded gullies downslope of culvert outlets, or (3) subsurface flow. Nearly 60% of the surveyed road length appeared to route water directly to stream channels or into gullies. Over time, the length of road connected to stream crossings has decreased, while the length of road discharging runoff that reinfiltrates to subsurface flow has increased, as roads have progressed up hillslopes and onto ridges in Lookout Creek and Blue River. The relatively constant proportion of the road network draining to gullies over time suggests that roads have the potential to become integrated into stream networks, even when constructed on unchannelled hillslope positions. An extended stream network, assumed to exist under storm conditions, was simulated for the basins using a digital elevation model. Although gullies and ditches differ from natural channels, extrapolation of field surveys using the GIS suggested that roads might extend the stream network by as much as 40% during storm events. It is hypothesized that such an effect could decrease the time of concentration of stormflow and contribute to higher peak discharges observed after clearcutting and road construction in these basins. Differences in the magnitude of road effects on peak flow generation may occur among road systems according to hillslope position of roads, road age, soil saturation, geologic substrate, and climate. These differences may explain the range of observed results from paired-basin studies examining road effects on hydrologic response. / Graduation date: 1994

The abundance and spatial heterogeneity of coarse woody debris (CWD) on the forest floor is a prominent feature of Pacific Northwest (PNW) forest ecosystems. The effect of CWD on soil solution chemistry, nutrient cycling and availability, soil physical structure and formation of soil organic matter, however, remains unknown. Therefore, studies on the spatial and temporal imprint of CWD on forest soils are timely and can fill critical gaps in our understanding of the role of CWD in PNW forest ecosystems. I investigated the effect of CWD on soils and soil solution at the H.J. Andrews Experimental Forest in a two-part study. Mineral soils were sampled beneath CWD to a depth of 60 cm. The top 15 cm of soil was also repeatedly sampled for seasonal differences. Control leachate, CWD leachate and soil solution from control soils and from under CWD were collected from the fall of 1999 until the spring of 2001. Results indicated that CWD leachates were much more acidic than water leaching from the forest floor without CWD. Intermediate stages of CWD decomposition had the highest concentrations of hydrophobic compounds and polyphenols of all stages of decay. Correspondingly, surface soils sampled from under well-decayed CWD were more acidic and had more exchangeable acidity and aluminum, and a lower percent base saturation than soils under the forest floor. Nutrient pools were not different under CWD, although nitrogen fluxes were slower under CWD. Although we had hypothesized that the spatial variability of CWD inputs may affect forest soils under CWD, we found that the spatial variability is much more temporal than I had hypothesized and is limited to the top five centimeters of the underlying soil. / Graduation date: 2002

Studies were conducted on the dynamics of live, standing recent dead, and standing old dead herbage for a desert grassland site in the southwestern United States. Data were collected at eleven sample dates from August 24, 1979 to October 18, 1980. Coefficients of variation for biomass data for most species exceeded 400% with only the most abundant species sampled with coefficients of variation less than 100%. Coefficients of variation generally were less than 80% for the perennial grasses as a group. The mean rate of transfer of biomass from live herbage to standing recent dead herbage was 0.21% per day for 203 days when expressed as a percentage of the peak live herbage. A rate of transfer of 0.53% per day of live herbage to standing dead for 109 days for perennial grasses in the desert grassland was found during early vegetative growth. A high proportion of leaves to culms was present during this period as compared to the summer growing season. Heavy precipitation in the early part of September accelerated growth of live herbage, and also accounted for losses of standing recent dead and standing old dead herbage to the surface litter component. The loss of dry leaves from standing grass culms due to rainfall impact contributes to an underestimate of net primary production. Standing old dead biomass accumulated following the depression in September. Transformation of the recent dead herbage to an appearance of old dead late in the summer also contributed to underestimating of current year production based on peak crop method due to the identification of recent dead herbage as the old dead component. Summation of growth increments by sample periods provided the highest estimate of aboveground net primary productivity when compared to estimates based on peak standing crop, summation of species peaks, and summation of significant growth increments by sample periods. Estimates of net productivity were 186% of the estimate at peak standing crop. Estimates of net production based on significant growth increments by sample periods yield the lowest value for net production, because poor precision of samples restricted data to few significant values. Based on the peak periods for standing biomass of lifeform groups, a minimum of four sample dates are recommended to estimate aboveground net primary production for semidesert grassland in southeastern Arizona. These sample dates include: (1) late April to sample spring peaks by perennial grasses, annual forbs and annual grasses; (2) late June to capture the spring trough; (3) late September to sample peak crops of perennial forbs, and half-shrubs; and (4) mid to late October to sample the fall peak for perennial grasses. Net production estimates by the peak crop method for perennial grasses varied from 18.7 g/m² in 1979 to 86.1 g/m² in 1980. This variability was attributed to the differences in the amount of rainfall in 1979 and 1980. This factor, therefore, largely influenced the repeatability of biomass estimates from one year to another. The large amount of time (approximately 644 man-hours) needed to sample and separate live and dead components by species for 20 quadrats at each harvest date, together with the year-to-year variability and the need for a minimum of four sample dates to effectively sample the desert grassland community, makes biomass data impractical for general use as a data base in land-use planning. However, this effort should be looked at from the standpoint of research studies describing the dynamics of range systems based on temporal characteristics and transfer functions to provide data which can help design management strategies for these range ecosystems.

This item was digitized as part of the Million Books Project led by Carnegie Mellon University and supported by grants from the National Science Foundation (NSF). Cornell University coordinated the participation of land-grant and agricultural libraries in providing historical agricultural information for the digitization project; the University of Arizona Libraries, the College of Agriculture and Life Sciences, and the Office of Arid Lands Studies collaborated in the selection and provision of material for the digitization project.

ABSTRACT ROBUSTNESS OF TWO FORMULAS TO CORRECT PEARSON CORRELATION FOR RESTRICTION OF RANGE by Dung Minh Tran Many research studies involving Pearson correlations are conducted in settings where one of the two variables has a restricted range in the sample. For example, this situation occurs when tests are used for selecting candidates for employment or university admission. Often after selection, there is interest in correlating the selection variable, which has a restricted range, to a criterion variable. The focus of this research was to compare Alexander, Alliger, and Hanges’s (1984) formula to Thorndike’s (1947) formula and population values using Monte Carlo simulation when the assumption of normal distribution is violated in a particular way. In both Thorndike’s and Alexander et al.’s correction formulas, values for the variances in the restricted and the unrestricted situations are required. For both formulas, the variance in restricted situations was a sample estimate. In the Monte Carlo simulation, the difference between the two approaches was that in Thorndike’s formula, the variance in the unrestricted situation was the population variance from the exogenous variable, whereas in Alexander et al.’s approach, the population variance was estimated based on the sample variance in the restricted situation. In the simulation, robustness situations were created from non-normal distributions for predicted group membership in a classification problem. As expected, Thorndike’s corrected correlation values were more accurate than Alexander et al.’s corrected correlation values, and Thorndike’s formula had a smaller standard error of estimates. Absolute values of the mean differences between the estimated and population correlations for Alexander et al.’s approach compared to Thorndike’s approach in robustness situations ranged from 1.37 to 2.15 larger. Nevertheless, Alexander et al.’s approach, which is based only on estimated variances, appears to be a worthwhile correction in most of the simulated situations with a few notable exceptions for non-normal distributions.

Open grassland productivity was measured within adjacent East Kootenay range units to evaluate forage availability and calculate elk (Cervus canadensis nelsoni) and cattle (Bos taurus) sustainable carrying capacity targets. This research extends rangeland monitoring with an analysis of site differentiation and comparative grazing pressure to 2008 population estimates. Significant productivity differences were found between grass and shrubs for range units (p=0.024 and p<0.0001) and different biogeoclimatic zones (p=0.042 and p<0.0001). Notable grazing pressure distinctions occurred: cattle exceeded the Rampart Mayook carrying capacity, elk exceeded the Pickering Hills carrying capacity, and both species had sustainable populations within the Power Plant range unit. These results provide clear direction for stock management and offer valuable rangeland insight. Furthermore, the study introduces cover-percentage productivity estimation (CPPE), a simple grassland productivity assessment method. Pearson correlation coefficients were significant and high between productivity results and cover estimates, indicating that CPPE will be a useful field tool.