Objectives: Tooth extraction initiates a cascade of events that often leads to local anatomic changes in the alveolar ridge. Ridge preservation is a surgical approach aimed at minimizing hard and soft tissue volume loss. There have been contradicting reports on the efficacy of socket grafting for alveolar ridge preservation. Interestingly, there is a paucity of adequately powered randomized controlled clinical trials. The purpose of this study was to assess the effect of the application of a socket grafting technique on alveolar ridge dimensional changes following tooth extraction. Methods: Healthy patients requiring the extraction of one single-rooted tooth on either arch, from second premolar to second premolar, excluding mandibular incisors, and who met the eligibility criteria were recruited. Patients were then randomly assigned to either the control group, consisting of tooth extraction alone, or the experimental group, which consisted of extraction and simultaneous ridge preservation using an allograft bone material to fill the socket and a dense polytetrafluoroethylene membrane (dPTFE) to seal it. Cone beam computed tomography (CBCT) was obtained immediately prior to extraction (baseline) and at 14 weeks. Linear measurements with the use of a tooth-supported stent were obtained immediately after extraction (baseline) and at 14 weeks. Linear and volumetric measurements were made using data obtained from the CBCTs. Masked, calibrated examiners performed all radiographic measurements. Measurements obtained included buccal keratinized tissue width, buccal and lingual plate height and width, alveolar ridge horizontal width (CBCT); and alveolar ridge volume changes. Digital planning of dental implants was performed in the ideal restorative location and need for additional grafting was virtually determined. The primary outcome of interest was volumetric reduction of the alveolar ridge at 14 weeks. Linear mixed model statistical analyses were used to compare the mean change in the measurements between the grafted and control groups. Results: A total of 59 subjects were recruited, of which 53 patients (27 control and 26 experimental) completed the study. No statistically significant difference was found between the two groups at baseline for any of the parameters analyzed. At the 14 week follow-up appointment there was an average loss in height of the buccal plate of 1.17 mm and 0.61 mm for the control (CG) and experimental (ARP) groups, respectively, showing statistical significance (p=0.012). The lingual plate height was reduced 0.7 mm in CG and 0.47 mm in ARP with no statistical significance (0.075). A linear loss in the buccal-lingual dimension of the alveolar ridge was noted radiographically in both groups, 1.68mm in CG and 1.07mm in ARP, which demonstrated a statistical significant difference between them (p=0.023). Volumetric analysis demonstrated a mean volume loss of 15.83% in the CG showing statistical significance from the 8.36% loss shown in the ARP group. This difference demonstrates a clinical significance when virtual planning of implant placement in the ideal restorative location revealed the need for additional grafting at 13/27 or 48% of CG and 3/26 or 11% of ARP sites. Additionally, a very robust, statistically significant correlation was noted between buccal bone plate width and reduction of alveolar bone volume after 14 weeks of healing (p< 0.0001). A multivariate regression analysis revealed that within the control group a buccal plate <1mm lead to >10% volumetric reduction, while the same reduction in the graft group was only seen when the buccal plate was less that 0.6mm. Conclusions: In this study, a novel volumetric analysis of alveolar ridge reduction after tooth extraction was performed, which demonstrated that socket grafting for alveolar ridge preservation does provide a therapeutic benefit. This finding was associated to a decreased probability of requiring additional grafting at the implant site. The thickness of the buccal plate at the time of extraction appears to be a valuable factor to predict the amount of resorption that will take place, meaning that more resorption should be expected, as the buccal plate gets progressively thinner.

The Cartoogechaye terrane (CT) is an enigmatic migmatite terrane within the Central Blue Ridge province of the southern Appalachians. Previous work identified exotic Pb isotope compositions within the CT (Quinn, 2012). More recent studies that mapped the extent of potentially exotic metaigneous lithologies yield U-Pb zircon ages consistent with a native Laurentian margin metasedimentary origin (Larkin, 2016). This study focused on the possible extent of similar lithologies in the Clyde quadrangle and provides further constraints on the crustal affinity of the CT. The Clyde quadrangle consists of four distinct lithologic packages: the CT, Ashe metamorphic suite, Great Smoky Group, and Grenville basement. Five samples within the Clyde quadrangle and one sample from Wayah Bald quadrangle were collected for detrital zircon (DZ) U-Pb geochronology and whole rock geochemistry for comparison similar anlayses from other bedrock units in the region. Dominant DZ age modes consist of the Grenville doublet (1050 Ma and 1150 Ma) or a modified version of it. Minor age modes exist at ~450 Ma, 600-750 Ma, and 1300-1550 Ma. Zircons for all but one sample display heterogeneous external and internal cathodoluminescence morphologies, consistent with a sedimentary protolith for the paragneisses. Whole rock compositions are consistent with weathering of and derivation from a local basement source. U-Pb age data are most consistent with an eastern Laurentian sedimentary provenance for five samples. The presence of 450-460 Ma grains is most consistent with high-grade Taconian regional metamorphism. The lack of a major Shawinigan age mode and zircon morphology for ca. 980-1050 Ma metamorphic zircons indicate that sample CLY16-1 is a syn-orogenic metasediment within the Grenville basement underlying the CT.

Optically stimulated luminescence (OSL) dating beach ridge sediments is one method for resolving barrier island growth at intermediate scales (decades-centuries), information that is lacking for Louisiana. This research combines OSL, GPR, aerial imagery, and cores to document temporal and spatial evolution of a Louisiana barrier island. Grand Isle is composed of beach ridges organized in distinct, unconformable sets that began forming 0.75 ka until 0.575 ka when deposition ceased, the ridges were partially eroded, and deposition resumed in a more eastward direction. The central ridges formed between 370±30 and 170±10 years ago at a rate of one ridge every 11.6 years with sand from the eroding Caminada headland that, with flanking barriers, forms the Bayou Lafourche transgressive depositional system. Grand Isle’s lithosome (92,600,000 cubic meters) requires an annual longshore transport of 128,625 cubic meters. The lithosome thickness (10 meters) and steady sediment supply stabilize the island relative to other Louisiana barriers.

The purpose of this research is to investigate the performance of some ridge regression estimators for the logistic regression model in the presence of moderate to high correlation among the explanatory variables. As a performance criterion, we use the mean square error (MSE), the mean absolute percentage error (MAPE), the magnitude of bias, and the percentage of times the ridge regression estimator produces a higher MSE than the maximum likelihood estimator. A Monto Carlo simulation study has been executed to compare the performance of the ridge regression estimators under different experimental conditions. The degree of correlation, sample size, number of independent variables, and log odds ratio has been varied in the design of experiment. Simulation results show that under certain conditions, the ridge regression estimators outperform the maximum likelihood estimator. Moreover, an empirical data analysis supports the main findings of this study. This thesis proposed and recommended some good ridge regression estimators of the logistic regression model for the practitioners in the field of health, physical and social sciences.

Introduction: The purpose of this study was to evaluate the changes in marginal ridge alignment occurring through normal growth and development from early childhood to late adulthood and to examine if any statistical variation exists between males and females. Methods: Dental casts of 38 subjects (15 females and 23 males) from the Iowa Growth Study were selected. The marginal ridge discrepancy was measured as the absolute value difference between adjacent marginal ridges of 20 interproximal contacts with both the ABO tool (data not shown) and a vertically mounted digital caliper. Upper and lower casts were tripoded to a level plane defined by the most posterior tooth and central point of the most erupted central incisor. A 15 subject calibration was used to measure inter-examiner reliability using the Cronbach’s Alpha and Kappa tests. The independent samples t test was used to examine the correlation of marginal ridge discrepancies between males and females. Results: Cronbach alpha (p ≤ .001) and Kappa test (p ≤ .01) show excellent inter-rater reliability. The independent sample t test showed no statistical significance, with minimal exception, in marginal ridge discrepancies between males and females matched for age (p > .05). Group 1 showed significantly higher number of marginal ridge discrepancies within ABO range of 0 – 0.5 mm of males and females compared to Group 2. Conclusion: Based on this study, no statistically significant differences were found in marginal ridge discrepancies between males and females. Also, the magnitude of marginal ridge discrepancies of erupting permanent teeth shows a decrease as an individual proceeds through growth and development and they remain relatively “level” during primary dentition.

Structural and geochemical analyses of the Top and Casino deposits, Bald Mountain-Alligator Ridge district, Nevada, were conducted to determine how structures affected gold deposition in Carlin-type deposit s. We also examined how permeability changed over time in a fault that cuts siltstone-dominated sedimentary rocks. The association of gold and related arsenic with faults at the margins of a Jurassic pluton and sedimentary rocks suggests that ore fluids migrated along faults and fracture s. Permeability of the faults changed over time within the Casino deposit, where the ore-controlling fault was a distributed conduit in the early stages of mineralization but a barrier and a localized conduit a t opposite ends of the deposit during later stages. Results indicate that faults may significantly influence patterns of ore deposition and change character over deposit-scale distances, and continued slip along faults may create clay-rich low-permeability faults that are mineralized during early stages of development.

當我們在應用迴歸分析法時，往往會遇到兩個或多個自變數間存在著線性 關係的問題，即所謂多重共線性(multicollinearity)； 多重共線性的存 在會使得一般被廣泛運用的最小平方估計式 (least square estimator) 出現不穩定的情形。此估計式之總變異(total variance)會因共線性之程 度愈高而發散，呈現出不穩定的現象，進而影響其預測模式的能力。因此 相繼有學者提出改良共線性模式的方法，以期達到較精確且穩健的預測結 果。脊迴歸分析法(Ridge regression analysis) 便是其中之一；對於有 共線性存在之模式，若使用傳統脊估式，其總變異會較最小平方估計式穩 定。但傳統脊估式為一個偏量估計式(biased estimator)，故本文考慮採 用Jackknife 取一法以求降低脊迴歸估計式之偏量(bias)，此二法併用所 產生之一個新的估計式即本文所謂改良式脊迴歸估計式。本文將應用線性 模式Jackknife 估計式，配合脊迴歸分析法導出改良式脊迴歸估計式。並 另外利用電腦模擬出不同程度之共線性資料以比較分析傳統脊迴歸係數與 改良式脊迴歸係數，此二者於預測模式上之表現。結果顯示：改良式脊迴 歸估計係數對於降低估計偏差方面有顯著之改善，其預測能力亦優於傳統 脊迴歸係數，因此改良式脊迴歸估計式較傳統脊迴歸估計式更加穩定、精 確。迴歸分析是目前應用最廣泛之統計工具，不論是經濟模型、商業方面 以及醫學上之應用等均以求精求準之預測為主要目的，本文提出之改良式 脊迴歸係數，於共線性存在之迴歸模式下兼備了傳統脊迴歸係數穩定估計 式變異以求精，降低估計偏量以求準之優點，因此改良式脊迴歸係數於預 測模式上之貢獻是值得肯定的。

<p>In regression with near collinear explanatory variables, the least squares predictor has large variance. Ordinary least squares regression (OLSR) often leads to unrealistic regression coefficients. Several regularized regression methods have been proposed as alternatives. Well-known are principal components regression (PCR), ridge regression (RR) and continuum regression (CR). The latter two involve a continuous metaparameter, offering additional flexibility.</p><p>For a univariate response variable, CR incorporates OLSR, PLSR, and PCR as special cases, for special values of the metaparameter. CR is also closely related to RR. However, CR can in fact yield regressors that vary discontinuously with the metaparameter. Thus, the relation between CR and RR is not always one-to-one. We develop a new class of regression methods, LSRR, essentially the same as CR, but without discontinuities, and prove that any optimization principle will yield a regressor proportional to a RR, provided only that the principle implies maximizing some function of the regressor's sample correlation coefficient and its sample variance. For a multivariate response vector we demonstrate that a number of well-established regression methods are related, in that they are special cases of basically one general procedure. We try a more general method based on this procedure, with two meta-parameters. In a simulation study we compare this method to ridge regression, multivariate PLSR and repeated univariate PLSR. For most types of data studied, all methods do approximately equally well. There are cases where RR and LSRR yield larger errors than the other methods, and we conclude that one-factor methods are not adequate for situations where more than one latent variable are needed to describe the data. Among those based on latent variables, none of the methods tried is superior to the others in any obvious way.</p>

The Department of Energy Oak Ridge Reservation (ORR) and the nearby adjoining City of Oak Ridge, Tennessee had experienced a rise in deer-vehicle collisions (DVCs) to the point where safety for employees and residents became a concern. I investigated the effect of hunting, land cover, road mileage, season, lunar phase, sex, and change in traffic patterns that coincide with work shifts on DVCs from 1975 - 2008. The study area was divided into grids of 1.5 km² each for administration and data recording by managing agencies. Statistical analyses were performed on the ORR (121 grids) and GIS analyses were performed on the entire study area that included ORR and the city of Oak Ridge (190 grids). The number of DVCs in 1975 was 16 and reached a high of 273 in 1985. Therefore, managers initiated a hunting program in 1985 and recorded deer harvest numbers by grid each year. Deer harvest has been occurring from 1985 until present, except when hunting was cancelled due to security concerns after the September 11 terrorist attacks in 2001. By 2008, the number of DVCs had decreased to 100 per year. When hunting first started in 1985, they harvested 926 deer. By 2008, that number was down to 481. I used GIS mapping to record DVCs, deer harvest per grid, landcover types, and mileage per grid to determine factors affecting DVCs on the smaller landscape. Following the initiation of annual hunts, both the annual deer harvest and the number of DVC’s have fallen, presumably because the overall deer population has declined from high pre-hunting levels. Deer harvest appears to be related to landcover characteristics, as a higher percentage of deer were harvested from forested areas than from other landcover types, as forested areas were most prominent. The months of October, November, and December had the highest DVC numbers. Increased traffic during starting and leaving shift times seem to increase the number of DVCs as well. Lunar phases only seem to significantly increase DVCs during the gestation and fawning seasons. Does are involved more frequently with DVCs than bucks during gestation, fawning and prerut, but not during the rutting season. I expect managers can use this data to guide intensive local management aimed at reducing DVCs by increasing the number of deer harvested and increased public education.

In regression with near collinear explanatory variables, the least squares predictor has large variance. Ordinary least squares regression (OLSR) often leads to unrealistic regression coefficients. Several regularized regression methods have been proposed as alternatives. Well-known are principal components regression (PCR), ridge regression (RR) and continuum regression (CR). The latter two involve a continuous metaparameter, offering additional flexibility. For a univariate response variable, CR incorporates OLSR, PLSR, and PCR as special cases, for special values of the metaparameter. CR is also closely related to RR. However, CR can in fact yield regressors that vary discontinuously with the metaparameter. Thus, the relation between CR and RR is not always one-to-one. We develop a new class of regression methods, LSRR, essentially the same as CR, but without discontinuities, and prove that any optimization principle will yield a regressor proportional to a RR, provided only that the principle implies maximizing some function of the regressor's sample correlation coefficient and its sample variance. For a multivariate response vector we demonstrate that a number of well-established regression methods are related, in that they are special cases of basically one general procedure. We try a more general method based on this procedure, with two meta-parameters. In a simulation study we compare this method to ridge regression, multivariate PLSR and repeated univariate PLSR. For most types of data studied, all methods do approximately equally well. There are cases where RR and LSRR yield larger errors than the other methods, and we conclude that one-factor methods are not adequate for situations where more than one latent variable are needed to describe the data. Among those based on latent variables, none of the methods tried is superior to the others in any obvious way.