This thesis presents content-related and construct-related validity evidence for science sub-tests within Student Selection Test (SST) in Turkey via underlying the content, cognitive processes, item characteristics, factorial structure, and group differences based on high school type. A total number of 126,245 students were present in the research from six type of school in the data of SST 2006. Reliability Analysis, Item Analysis, Principle Component Analysis (PCA) and one-way ANOVA have been carried out to evaluate the content-related and construct-related evidence of validity of SST. SPSS and ITEMAN programs were used to conduct the above-mentioned analyses. According to the results of content analysis, science items in the SST 2006 found to be measuring various cognitive processes under knowledge, understanding and problem solving cognitive domains. Those items loaded under three factors according to PCA findings which were measuring very close dimensions. Moreover, a threat to validity was detected via one-way ANOVA due to significant mean difference across high school types.

Student selection test in Turkey compose of two parts. The purpose of the first part is to assess students&rsquo / higher order thinking skills like analytical thinking, interpretation and reasoning about elementary school curriculum and 9th grade curricula objectives. On the other hand, second part of the test aims to assess students&rsquo / higher order thinking skills given in the high school curriculum. The main aim of this thesis is to analyze to what extend 2006, 2007 and 2008 student selection tests biology items assess higher order cognitive skills. In accordance with this purpose, elementary and high school curriculum and the appropriateness of the questions in the student selection test with the educational objectives of the curriculum are examined. In addition, dimensions of 2006, 2007, and 2008 SST biology items are examined by Exploratory Component Analysis and Confirmatory Component Analysis techniques. The result of those analysis revealed that SST biology items mostly focus on remembering skill and fail to assess higher order thinking skills. Additionally, there is not any consistency among 2006, 2007, and 2008 SSTs biology items in terms of dimensions which means there is not any construct in biology subtests of SSTs. The other aim of the present study is to identify how much academic and non-academic factors explain the biology achievement. While for academic factors reading comprehension, mathematics, physics, and chemistry achievements of students are used, age, gender, and school type are used for non-academic factors. Findings of the research revealed that academic factors, especially chemistry achievement, have significant affect on biology achievement. In terms of non-academic factors, graduating from selecting high school has important role for biology achievement. Additionally, older students and girls tend to have higher grades in biology.

The objective of this work was to understand microbial population density and diversity, both spatially and temporally, in wetland mesocosms to gain a better fundamental understanding for use in the optimization and design of constructed wetlands (CWs). A standardized community level physiological profiling (CLPP) data analysis protocol was adapted and utilized for CW mesocosms. A new one-dimensional metric was developed to track community divergence using BIOLOGTM ECO plate data. The method proved easy to use, did not require a background in multivariate statistics, and accurately described community divergence in mesocosm systems. To study mesocosm biofilm-bound bacterial communities an appropriate detachment protocol was required. Various shaking protocols were evaluated for their effectiveness in the detachment of bacteria from mesocosm pea gravel, with a focus on detachment of viable and representative bacterial communities. A protocol based on mechanical shaking with buffer and enzymes was identified as an optimal approach and used further in this study. The bacterial communities associated with the interstitial water, pea gravel media, and rhizospheric regions from both planted and unplanted CW mesocosms were profiled using the CLPP method and compared. Vertical community stratification was observed for all mesocosm systems. Rhizospheric communities were found to be significantly more active than their gravel-associated counterparts, suggesting that although rhizospheric bacteria were less abundant in the mesocosms they may play a more significant role in the removal and fate of water born contaminants. The start-up dynamics of CW mesocosms was investigated using the CLPP and standard CW characterization methods over an eight month period. All mesocosms showed a steep increase in interstitial community divergence until day 75-100, at which point a steady-state was reached. The interstitial communities were also characterized in terms of similarity based on experimental design treatments (planted/unplanted and origin of seeding inoculum). Four stages were identified during the start-up consisting of an initial stage where mesocosm communities were differentiated based on origin of the inoculum, a period where adjustments and shifts occurred in all mesocosm, a time where all mesocosm communities were quite similar, and a final state where community differentiations were made based plant presence in the mesocosms.

The objective of this work was to understand microbial population density and diversity, both spatially and temporally, in wetland mesocosms to gain a better fundamental understanding for use in the optimization and design of constructed wetlands (CWs). A standardized community level physiological profiling (CLPP) data analysis protocol was adapted and utilized for CW mesocosms. A new one-dimensional metric was developed to track community divergence using BIOLOGTM ECO plate data. The method proved easy to use, did not require a background in multivariate statistics, and accurately described community divergence in mesocosm systems. To study mesocosm biofilm-bound bacterial communities an appropriate detachment protocol was required. Various shaking protocols were evaluated for their effectiveness in the detachment of bacteria from mesocosm pea gravel, with a focus on detachment of viable and representative bacterial communities. A protocol based on mechanical shaking with buffer and enzymes was identified as an optimal approach and used further in this study. The bacterial communities associated with the interstitial water, pea gravel media, and rhizospheric regions from both planted and unplanted CW mesocosms were profiled using the CLPP method and compared. Vertical community stratification was observed for all mesocosm systems. Rhizospheric communities were found to be significantly more active than their gravel-associated counterparts, suggesting that although rhizospheric bacteria were less abundant in the mesocosms they may play a more significant role in the removal and fate of water born contaminants. The start-up dynamics of CW mesocosms was investigated using the CLPP and standard CW characterization methods over an eight month period. All mesocosms showed a steep increase in interstitial community divergence until day 75-100, at which point a steady-state was reached. The interstitial communities were also characterized in terms of similarity based on experimental design treatments (planted/unplanted and origin of seeding inoculum). Four stages were identified during the start-up consisting of an initial stage where mesocosm communities were differentiated based on origin of the inoculum, a period where adjustments and shifts occurred in all mesocosm, a time where all mesocosm communities were quite similar, and a final state where community differentiations were made based plant presence in the mesocosms.

The dynamics captured in the ocean surface current data provided by satellite altimetry has been a subject of debate since the past decade. In particular, the contribution of surface and interior dynamics to altimetry remains unclear. One avenue to settling this issue is to compare the turbulence (for example, the nature of spectra and interscale fluxes) captured by altimetry to theories of two-dimensional, surface and interior quasigeostrophic turbulence. In this thesis, we focus on mesoscales (i.e., scales of the order of few hundred kms) that are well resolved by altimetry data. Aspects of two dimensional, three dimensional, geotropic and surface quasigeostrophic turbulence are revisited and compared with the observations. Specifically, we compute kinetic energy (KE) spectra and fluxes in five geographical regions (all over the globe) using 21 years of 0.25◦resolution daily data as provided by the AVISO project. We report a strong forward cascade of KE at small scales (accompanied by a spectral scaling of the form k−3) and a robust inverse cascade at larger scales. Further, we show that the small diver-gent part in horizontal velocity data drives the strong forward flux of KE. Indeed, on considering only the non-divergent part of the flow, in accord with incompressible two-dimensional turbulence, the inverse cascade is unaffected, but the forward transfer becomes very weak and the spectral slopes over this range of scales tend to a relatively steeper k−3.5scaling. We note that our results do not agree with interior first bar clinic mode quasigeostrophic (incorrect strength of forward flux) or surface-quasigeostrophic (incorrect spectral slopes) turbulence. Rather, the results are compatible with rotating shallow water and rotating stratified Boussinesq models in which condition of geostrophic balance is dominant but the divergence of horizontal velocity field is not exactly zero. Having seen the “mean” picture of fluxes and spectra from altimetry, in the second part of the thesis we investigate the variability of these entities. In particular, we employ Empirical Or-thogonal Function (EOF) analysis and focus on the variability in the spectral flux. Remarkably, over the entire globe, irrespective of the region under consideration, we see that the first two EOFs explain a large part of the variability in flux anomalies. The geometry of these modes is distinct, the first represents a single signed transfer across scales (i.e. large to small or small to large depending on the sign of the associated principal component), while the second is a mixed mode in that it exhibits a forward/inverse transfer at large/small scales.