While there is general agreement among researchers in the field of language and learning disabilities upon the language hypothesis for reading failure, little research has been explored concerning the relationship between the phonological production skills of preschool children and the same children's prereading abilities in kindergarten. This study examined two aspects of phonological skill (a) the relationship of early phonological production errors and later success on phonological awareness and general prereading skill, and (b) determining if prereading deficits in a group of children with a history of lanquage delay reside specifically in the phonological awareness items or the prereading score in general. The subjects used for this study included 29 "normal" talkers and 30 "late talkers", as determined by the Language Development survey (Rescorla, 1989) when the subjects were between 20-34 months. When the subjects were three years old, a language sample was obtained and later phonemically transcribed from audio tape and entered into the PEPPER computer program to compute the percentage consonants correct (PCC) for each child. The subjects were later evaluated during their kindergarten year for reading readiness, using the Developmental Skills Checklist. This study found that Late Talkers have significantly lower PCCs than there normal talking peers at age three, but their PCCs do not predict their prereading or phonological awareness skills at kindergarten. Phonological awareness was further investigated in terms of supraseqmental and segmental levels of phonological awareness, there was no significant difference between the groups on either level of phonological awareness. However, there was a nonsignificant trend (p

The contemporary research suggests that some children who present with early language delays as toddlers outgrow their delays while others continue to develop long-term language difficulties. Several studies over the years have focused on factors that might aid in predicting the outcome of late talkers. This current study emphasized exploring gender as a possible predictive factor. The purpose of this study was to determine if significant differences exist in the rate of growth in language skills, as indexed by scores on the Developmental Sentence Scoring (DSS) procedure (Lee, 1974) of boys versus girls who are late to start talking as toddlers. The research hypothesis was that boys who present as LT toddlers would score significantly higher than LT girls at each age level tested. The DSS is a norm-referenced instrument that assesses age-appropriate morphological development and syntax. The LT subjects used were part of the Portland Language Development Project, a longitudinal study. Spontaneous speech samples were collected, transcribed, and analyzed using the DSS procedure once each year from the time they were approximately 3 years of age, until the age of 7. Late talking children in this present study were grouped by gender. A Chi Square test was used to determine if the proportion of males scoring above the 10th percentile on the DSS was significantly different than the proportion of females scoring above the 10th percentile at each age. Results from this analysis indicated that at the age of 3 years, more boys than girls scored above the 10th percentile on the DSS. There were no significant differences found at the ages of 4, 5, 6, and 7. At-test was used to compare average DSS scores between the two genders for each year of the study. This test revealed a significant difference between the LT girls' and LT boys' scores at the age of 3 years. No significant differences were found for the subsequent years. However, difference between boys' and girls' scores at age 7 approached significance, with boys again scoring higher.

The narrative, just like any lectured or monologue information which is shared, does not depend to any great extent on context. Therefore, ability to encode and decode the information to be presented verbally is required, that is, in order for the speaker to be able to verbalize what he or she wants to say while taking into consideration the listener's needs. This indicates that production of strong narratives depends on higher level language skills, and so children's narratives provide a sensitive means of assessing children's language development. The purpose of this study was to compare the narrative ability of children at second grade age, using a wordless picture book, with differing rates of language development. Subjects were assigned to three diagnostic groups, (normal, history of expressive language delay, and chronic expressive language delay) based on their original diagnoses at 20 - 34 months (normal or late-talker) and their Developmental Sentence Score (Lee, 1974) at second grade age. During the second grade assessment, each subject was audiotaped producing a spontaneous narrative using a wordless picture book. These narratives were scored on eight measures: Mean Length of Utterance per T-Unit, TypeToken Ratio, Narration Length in T-Units, Information, Average Sentence Length, Lexical Diversity, Cohesion, and Narrative Stage. Results of the ANOVA and the Duncan Test multiple comparison procedures revealed significant differences among the groups on only one variable - Mean Length of Utterance per T-Unit. Children in the normal language group and the history of expressive language delay group performed significantly better than the group of children with chronic expressive language delay. No significant differences were found between the normal language group and the history of expressive language delay subjects.

Current research in early language development suggests that children who were diagnosed during preschool with expressive language delay would demonstrate difficulties during elementary school years (Scarborough and Dobrich, 1990). This purpose of the present study was to qualitatively describe the outcome of children with a history of early language delay and differing levels of expressive performance (ELD and HELD), as reported by the parents. A questionnaire was developed to determine the children's current age and grade level, past and present reading ability and reading interests, best and worst academic subject, special services and diagnosed disability, speech and language concerns, friendships concerns, and behavioral and motor issues. The study used Developmental Sentence Scoring (Lee, 197 4), which determined which children continued to function below the normal range at second grade. Once identified, these children were placed into two groups indicating early language delay (ELD) and history of early language delay (HELD). The data was collected from parent interviews and placed into tables for analysis. Case vignettes were developed for each ELD and HELD subject. The suggested trends from the study include: Differences in reading material, literacy related play activities, number of friends, and similar special services received in school.

Bragg spaced quantum wells represent a unique class of resonant photonic materials, wherein a photonic bandgap is created by the periodic spacing of quantum wells and the associated variation in the complex susceptibility (index and absorption) of the material. Interest in BSQWs has grown in the past decade due to their large ultrafast nonlinearities and the corresponding large ultrafast reflectivity changes and transmissivity. These nonlinearities are of particular interest in areas of communication technology, where ultrafast all-optical logic components have become increasingly in demand. This research will further investigate BSQWs and the for the first time effects of spin-dependent nonlinear excitation on their photonic band structures. It will also investigate how these effects can be used in all-optical polarization switching and tunable optical buffer (slow light) applications.

Due to the increasing cost of soybean meal and concerns of excess N being excreted into the environment, new protein supplements have been developed. Two products that have shown potential in increasing N utilization efficiency are slow release urea (SRU; Optigen) and ruminal escape protein derived from yeast (YMP; DEMP). The objective of this study was to assess the effects of feeding these 2 supplements in high-forage [(54% of total dietary dry matter (DM)] dairy diets on nutrient utilization, feed efficiency, lactational performance of dairy cows, and their impacts on income-over feed costs. Twelve multiparous dairy cows were used in a triple 4 × 4 Latin square design with one square consisting of ruminally cannulated cows. Treatments included: 1) control, 2) SRU-supplemented total mixed ration (TMR, SRUT), 3) YMP-supplemented TMR (YMPT), and 4) SRU and YMP-supplemented TMR (SYT). The control consisted only of a mixture of soybean meal and canola meal (SBMCM) in a 50:50 ratio. The SRU and the YMP were supplemented at 0.49% and 1.15% DM, respectively. The experiment consisted of 4 periods lasting 28 d each (21 d of adaptation and 7 d of sampling). Cows fed YMPT and SYT had decreased intake of DM, and all supplemented treatments had lower crude protein intake compared to those fed the control. Milk yield tended to have the greatest increase in YMPT compared with the control (41.1 vs. 39.7 kg/d) as well as a tendency for increased milk fat and protein yields. Feed efficiencies based on yields of milk, 3.5% fat-corrected milk, and energy-corrected milk increased at 10-16% due to protein supplementation. Cows fed with protein supplements partitioned less energy toward body weight gain, but tended to partition more energy toward milk production. Efficiency of use of feed N to milk N increased by feeding SRUT and YMPT, and milk N-to-manure N ratio increased in YMPT. Cows fed SRUT or YMPT tended to improve income-over feed costs. Overall results from this experiment indicate that replacing SBMCM with SRU and YMP in high-forage dairy diets can be a good approach to enhance dairy profitability through improved nutrient utilization efficiencies by lactating dairy cows.

A true time delay multi-bit MEMS phase shifter topology based on impedance-matched slow-wave CPW sections on a 500µm thick quartz substrate is presented. Design equations based on the approximate model for a distributed line is derived and used in optimization of the unit cell parameters. A semi-lumped model for the unit cell is derived and its equivalent circuit parameters are extracted from measurement and EM simulation data. This unit cell model can be cascaded to accurately predict N-section phase shifter performance. Experimental data for a 4.6mm long 4-bit device shows a maximum phase error of 5.5° and S11 less than -21dB from 1-50GHz. A reconfigurable MEMS transmission line based on cascaded capacitors and slow-wave sections has been developed to provide independent Zo - and β-tuning. In the Zo-mode of operation, a 7.4mm long line provides Zo-tuning from 52 to 40Ω (+/-2Ω) with constant phase between the states through 50GHz. The same transmission line is reconfigured by addressing the MEM elements differently and experimental data for a 1-bit version shows 358°/dB (or 58°/mm) with S11 less than -25dB at 50GHz. The combined effect of Zo- and β-tuning is also realized using a 5-bit version. An electronically tunable TRL calibration set that utilizes a 4-bit true time delay MEMS phase shifter topology, is demonstrated. The accuracy of the tunable TRL is close to a conventional multi-line TRL calibration and shows a maximum error bound of 0.12 at 40GHz. The Tunable TRL method provides for an efficient usage of wafer area while retaining the accuracy associated with the TRL technique, and reduces the number of probe placements.

This thesis analyzes the wireless propagation modeling of a 2.6 GHz band channel around the Tampa Bay area. Different empirical models are compared against measured data, and an adapted model, specific for the Tampa Bay area, is presented that builds on the accuracy of existing models. The effects of the propagation characteristics along bridges are also discussed, and a two-slope model is presented. The proposed models are based on a simple linear regression method, and statistical tests are evaluated for reliability thereof. The analysis also investigates the statistical properties of shadowing effects imposed on the wireless channel. The spatial correlation properties of shadowing effects are investigated in detail, and an extension of existing correlation models for shadowing effects is suggested where the correlation properties are studied in different distance ranges rather than the whole service coverage area.

Naturally fractured reservoirs have attracted an increased interest of exploration and production geophysics in recent years. In many instances, natural fractures control the permeability of the reservoir, and hence the ability to find and characterize fractured areas of the reservoir represents a major challenge for seismic investigations. In fractured and porous reservoirs the fluid affects elastic anisotropy of the rock and also causes significant frequency dependent attenuation and dispersion. In this study we develop a mathematical model for seismic wave attenuation and dispersion in a porous medium in a porous medium with aligned fractured, caused by wave induced fluid flow between pores and fractures. In this work fractures in the porous rock are modelled as very thin and highly porous layers in a porous background. Dry highly porous materials have low elastic moduli; thus dry skeleton of our system contains thin and soft layers, and is described by linear slip theory. The fluid saturated rock with high-porasity layers is described by equations of poroelasticity with periodically varying coefficients. These equations are analyzed using propagator matrix approach commonly used to study effective properties of layered system. This yields a dispersion equation for a periodically layered saturated porous medium taking into account fluid communication between pore spaces of the layers. Taking in this dispersion equation a limit of small thickness for high-porosity layers gives the velocity and attenuation as a function of frequency and fracture parameters. The results of this analysis show that porous saturated rock with aligned fractures exhibits significant attenuation and velocity dispersion due to wave induced fluid flow between pores and fractures. / At low frequencies the material properties are equal to those obtained by anisotropic Gassmann theory applied to a porous material with linear-slip, interfaces. At high frequencies the results are equivalent to those for fractures with vanishingly small normal slip in a solid (non-porous) background. The characteristic frequency of the attenuation and dispersion depends on the background permeability, fluid viscosity, as well as fracture density and spacing. The wave induced fluid flow between pores and fractures considered in this work has exactly the same physical nature as so-called squirt flow, which is widely believed to by a major cause of seismic attenuation. Hence, the present model can be viewed as a new model of squirt-flow attenuation, consistent with Biot’s theory of poroelasticity. The theoretical results of this work are also limited by the assumption of periodic distribution of fractures. In reality fractures may be distributed in a random fashion. Sensitivity of our results to the violation of the periodicity assumption was examined numerically using reflectivity modelling for layered poroelastic media. Numerical experiments for a random distribution of fractures of the same thickness still show surprisingly good agreement with theoretical results obtained for periodic fractures. However this agreement may break down if fracture properties are allowed to vary from fracture to fracture. The results of this thesis show how to compute frequency dependences of attenuation and velocity caused by wave induced fluid flow between pores and fractures. These results can be used to obtain important parameters of fractured reservoirs, such as permeability and fracture weakness, from attenuation measurements. The major requirement for the success of such an approach is that measurements must be made in over a relatively broad frequency range.

The close proximity of the Nicoya Peninsula to the Cocos-Caribbean Subduction zone plate boundary makes it a prime location to use GPS to study episodic tremor and slip. Nicoya Peninsula currently has operating networks of both continuous GPS (CGPS) and seismic stations designed to identify and characterize the pattern of episodic tremor and slip (ETS) events along the seismogenic zone under Costa Rica's Pacific Margin. The occurrence of slow slip events has been previously postulated in this region based on correlated fluid flow and seismic tremor events recorded near the margin wedge in 2000 and from sparse GPS observations in 2003. Paucity of data prevented details of these events from being resolved. In May 2007 a slow slip event was recorded on our densified GPS network. This slow slip event was also accompanied by seismic tremor, worked up by colleagues at the University of California - San Diego. I will present the GPS time series, correlated with the seismic tremor for the event in May 2007. I will also present the inferred pattern of slip on the plate interface from elastic half space inversion modeling compared with the tremor and Low Frequency Earthquake (LFE) locations. The geodetic slip and seismic tremor co-locate temporally very well. Spatially the seismic tremor and LFE locations are offset but not independent of both the up dip and down dip patches of geodetic slip. The identification of these slow slip events enhances our understanding of the nuances of the interseismic period. Previous studies of the interseismic strain accumulation patterns in the region of the Nicoya Peninsula have not accounted for the occurrence of slow slip, thus underestimating the magnitude of locking on the fault plane. My study resolves this bias by using our CGPS network to estimate the interseismic surface velocity field, accounting for the May 2007 slow slip event. I will present the results of this velocity field estimation and the results of inversions for locking patterns on the fault plane. My study has also elucidated a potential temporal variability in the locking pattern on the fault plane beneath Nicoya.