A Geometric Look At Repeated Measures Design with Missing Observations

In this paper, we will provide a geometric view of Repeated Measures Design for unequal number of subjects per treatment that has missing observations. For our geometric development we restrict our design to three levels of factor A and four levels of factor B. The purpose of this paper is to develop a test statistics for hypotheses of interest i.e. no main effect A, no main effect B, and no AB interaction

Cattle as partners in conservation: the effects of grazing on indicators of rangeland health

2018 Summer.Includes bibliographical references.For centuries, the natural ecology of rangelands has supported large herds of herbivores. The partnership between these herbivores and the land has usually been, and can continue to be a sustainable one. However, the debate over the use of public lands for cattle grazing continues to intensify. Scientific literature and corresponding recommendations regarding cattle management on rangelands are conflictual. This thesis proposes that the resolution is not to remove grazing from rangelands, but to effectively manage grazing for specific landscapes and ecosystem types. Grassland ecosystems are highly dynamic and maintained by continuous adaptation to biotic and abiotic events. Therefore, strategic grazing management that also incorporates dynamic adaptation to environmental conditions may produce successful outcomes with respect to cattle grazing and sustainable land management. The objective of this study was to compare selected indicators of rangeland health in ungrazed areas to adjacent areas where strategic grazing management had been implemented. It was hypothesized that compared to areas excluded from grazing, areas where strategic grazing was implemented would exhibit: increased nutrient cycling by integration of organic carbon and nitrogen into the soil, increased abundance of native graminoids and native forbs, and reduced abundance of noxious weeds. It was hypothesized that forage quality would follow a particular pattern because of grazing: a decrease in forage quality shortly following grazing, an increase in forage quality with a period of rest, and a decrease in forage quality with continued absence of grazing. Paired grazed and ungrazed areas were established in 6 pastures across a grassland valley on Colorado's Front Range, which had not been grazed for at least 10 years. In 2016, baseline data were collected from both grazed and ungrazed areas prior to grazing. Subsequent data were collected in 2017, following strategic grazing management and adequate rest. Linear mixed models were used to compare differences between grazed and ungrazed areas. Results indicated no significant differences in soil organic carbon (P = 0.97), total nitrogen (P = 0.64), relative abundance of native graminoids (P = 0.15) or relative abundance of forbs/subshrubs (P = 0.74) between grazed and ungrazed areas. In regards to forage quality, crude protein was lower (P = <0.01) and neutral detergent fiber was higher (P = 0.05) at the conclusion of the grazing period, but acid detergent fiber did not differ (P = 0.51) in grazed versus ungrazed areas. Additionally, areas that were grazed in the spring and received 2-3 months of rest demonstrated higher forage quality than areas that were grazed in the fall and received 9-10 months of rest as indicated by higher crude protein (P = 0.03), and a tendency for lower neutral detergent fiber (P = 0.06), but no difference in acid detergent fiber (P = 0.97). Chi-square tests for soil and vegetation variables detected no variation between pairs of grazed and ungrazed areas across the landscape. This suggested that the biological variability within and between grazed and ungrazed areas was minimal, and that the strategic grazing regime, which incorporated flexibility in grazing intensity, stocking density, and season of grazing, produced homogeneous effects across all pastures. The results of this study indicated that one year of strategic grazing does not significantly affect select soil and vegetation variables and that further study is needed in order to inform application. As part of a long-term project, this collection of data and analysis was important for the initiation of a collaborative monitoring process, which will eventually determine if strategic grazing management proves to be helpful or harmful for land management goals. Continued research will aid ranchers and land managers in developing collaborations so that cattle might serve as partners in the conservation of rangelands, while maintaining animal performance and beef production objectives. Effective livestock management is key. Therefore, the human decision-making dimension is imperative to incorporate in future grazing studies

Partnerships on Colorado conservation lands: social-ecological outcomes of collaborative grazing management

Includes bibliographical references.2022 Fall.To view the abstract, please see the full text of the document

Analysis of Covariance For Repeated Measures Design with Missing Observations

analysis of covariance might be one of the most miS4nderstood and inadequately taught of all applied statistical methods. Many methods books do not deQl with it at all (Cullman et. aI., 1982), or sparingly (Brownlee, J965), and most of those that treat it substantially, such as Federer (1955), Snedecor and Cochran (J 980), Steel and Torrie (1980), and Winer (1971), concentrate on balanced data, namely those which have equal numbers of observations in the subclasses. What happens if the data are not balanced and moreover if some of the observations are missing? The missing observations complicate computations and affect what is estimable. The analysis of covariance would become more complex. The application of geometry in the analysis of covariance may of fer an understanding of the analysis as well as broaden the variety of methods that can be considered. When there are no missing observations on the repeated measures Factor(s) , computational algorithms can be used (see Henderson and Henderson, 1979)

Ultrasonic Characterization of Horizontal Density Variations in Oriented Strandboard

Random flake deposition in mat forming of oriented strandboard (OSB) results in inherent horizontal density variation that affects the panel strength quality. In this paper, a silicon gel coupled ultrasonic transmission (UT) was used to locate, map, and validate the horizontal density distribution in laboratory-made OSB. Two test boards were manufactured at each of three nominal density (ND) and three resin content (RC) levels. The UT variables velocity, attenuation, and root mean square voltage formed excellent complementary predictors of density for all RC and panel types. Based on the allowable ±10% variation in the average measured densities, both the general and polynomial models provided improved density prediction for boards at higher RC and ND levels. Using the contour and out-of-limits plots, the predicted horizontal densities gave a reasonable spatial approximation to the measured densities. All 6% RC panels with densities of 0.60 g/cm3 or greater conformed well to the limits, with declining conformity towards the lower RC panels

Fitting Weibull and Lognormal Distributions to Medium-Density Fiberboard Fiber and Wood Particle Length

Fiber lengths were analyzed for random samples of medium-density fiberboard (MDF) fibers and wood particles taken from eleven different populations. For six of the samples, the lognormal distribution fit the data, while the Weibull distribution did not. For three of the samples, the Weibull fit the data, while the lognormal did not. For two of the samples, both the lognormal and Weibull fit the data. Conclusions were based on hypothesis tests imposing a bound of 0.05 on the probability of making a Type I error for each test. Tests were based on large sample 95% nonparametric simultaneous confidence bands for the underlying cumulative distribution functions of the data

APCs in sinus floor augmentation.

After tooth loss in the posterior area of the maxilla, sinus floor elevation is often required to compensate the vertical bone loss due to sinus pneumatization. This narrative review reports on the potential benefits of autologous platelet concentrates (APCs) during this procedure. As for transcrestal approach, APCs have been used as "sole" substitute/graft. However, because of the low number of clinical trials available with PRGF, and even none for PRP, no definitive conclusions can be made regarding their efficacy. The number of studies on the use of L-PRF were outnumbered indicating good feasibility for vertical bone gain, with a high implant survival rate and a low degree of complications. PRP and PRGF have not been studied as a "single/sole" substitute for a one-stage lateral window approach, probably because of the weak physical characteristics of the membranes. L-PRF alone appears to be a predictable grafting material for lateral maxillary sinus grafting and a reduced RBH should not be considered as a risk factor. Compared to a "standard" bone substitute L-PRF shows slightly less vertical bone gain (consider enough membrane application and use of bony window as new sinus floor roof over the implant apices), enhanced early resorption (first 6 months after application), but a similar stable bone gain afterward. For a two-stage lateral window approach, APCs "alone" cannot be recommended, due to their weak withstand to the sinus pneumatization forces. APCs combined with bone substitutes seem to accelerate bone formation, without any additional benefits on the long-term new bone gain. The use of L-PRF membranes for the treatment of perforations appears to be an effective treatment option, but further clinical studies are needed to confirm this. Even though the abovementioned statements are based on large numbers of studies, additional RCTs comparing APCs with different types of grafting procedures for sinus elevation are needed

Activity Monitoring of Functional OprM Using a Biomimetic Microfluidic Device

International audienceThis paper describes the fabrication and use of a biomimetic microfluidic device for the monitoring of a functional porin reconstituted within miniaturized suspended artificial bilayer lipid membrane (BLM). Such a microfluidic device allows for 1) fluidic and electrical access to both sides of the BLM, 2) reproducible membrane protein insertion and long-term electrical monitoring of its conductance (Gi), thanks to the miniaturization of the BLM. We demonstrate here for the first time the feasibility to insert a large trans-membrane protein through its β-barrel, and monitor its functional activity during more than 1 hour (limited by buffer evaporation). In this paper, we specifically used our device for the monitoring of OprM, a bacterial efflux channel involved in the multidrug resistance of the bacteria Pseudomonas aeruginosa. Sub-steps of the OprM channel conductance were detected during the electrical recordings within our device, which might be due to oscillations between several structural conformations (sub-states) adopted by the protein, as part of its opening mechanism. This work is a first step towards the establishing of a genuine platform dedicated to the investigation of bacterial proteins under reconstituted conditions, a very promising tool for the screening of new inhibitors against bacterial channels involved in drug resistance