5,139 research outputs found
Clinical and radiographic observation of the periodontium in patients undergoing orthodontic therapy: first twenty-seven months
Thesis (MSD) --Boston University (Periodontics).Includes bibliographic references: leaves 84-89.Twenty-two male patients from 12-14 years of age were selected prior to active orthodontic therapy at Boston University School of Graduate
Dentistry's Departmant of Orthodontics. These patients were projected
to undergo full-banded orthodontic treatnent.
The objective of this investigation was designed as a long tenn project
to document the quantitative and qualitative changes occurring in the
periodontium during and following orthodontic therapy.
The patients were examined for the first 9 month period by
Dr. Stuart Sears and Dr. Sergio Tejedor-Leon.
Relocation of two families reduced the number of patients to twenty
which were examined for the second 9 nonth period by Dr. Robert E. Roe
and Dr. Robert P. Rubins. [TRUNCATED
Geometric phase for an adiabatically evolving open quantum system
We derive an elegant solution for a two-level system evolving adiabatically
under the influence of a driving field with a time-dependent phase, which
includes open system effects such as dephasing and spontaneous emission. This
solution, which is obtained by working in the representation corresponding to
the eigenstates of the time-dependent Hermitian Hamiltonian, enables the
dynamic and geometric phases of the evolving density matrix to be separated and
relatively easily calculated.Comment: 10 pages, 0 figure
An Examination of Georgia Young Farmer Program Participants’ Learning Style Preferences
This study was designed to describe Georgia Young Farmer Program participants’ learning style preferences. Using survey research methods, a questionnaire was designed to collect data related to the purpose of the study. The population for this study included active members in the program. Study findings showed that participants had a preference for kinesthetic learning over visual and auditory learning. While participants indicated a preference for kinesthetic learning, all three learning styles were deemed effective. Preferences for learning styles and perception of effectiveness did not differ by personal characteristics. Recommendations include taking learning style preferences into account when designing and delivering programming, training for teachers, and continuing to assess learners’ preferences
Performance of Trajectory Models with Wind Uncertainty
Typical aircraft trajectory predictors use wind forecasts but do not account for the forecast uncertainty. A method for generating estimates of wind prediction uncertainty is described and its effect on aircraft trajectory prediction uncertainty is investigated. The procedure for estimating the wind prediction uncertainty relies uses a time-lagged ensemble of weather model forecasts from the hourly updated Rapid Update Cycle (RUC) weather prediction system. Forecast uncertainty is estimated using measures of the spread amongst various RUC time-lagged ensemble forecasts. This proof of concept study illustrates the estimated uncertainty and the actual wind errors, and documents the validity of the assumed ensemble-forecast accuracy relationship. Aircraft trajectory predictions are made using RUC winds with provision for the estimated uncertainty. Results for a set of simulated flights indicate this simple approach effectively translates the wind uncertainty estimate into an aircraft trajectory uncertainty. A key strength of the method is the ability to relate uncertainty to specific weather phenomena (contained in the various ensemble members) allowing identification of regional variations in uncertainty
Interactive effects between group and single-subject response patterns
A two-part study was undertaken to investigate the effects of movement experiences on lower extremity function during impact activities. Group and single-subject performances were evaluated for a total of 12 male volunteers during landing (Study I) and running (Study II) activities. Standard biomechanical techniques were used to obtain kinematic (200 Hz) and kinetic (1000 Hz) data during soft, normal and stiff-knee landings (Study I) and for under, normal, and over-stride running (Study II). Performance trials were tested for normality, condition differences were documented and multiple regression models were computed to predict the first (F1) and second (F2) maximum vertical forces during landing and the maximum impact force (IF) during running. Results of the study identified condition differences with no deviations from normality, thereby achieving the goal of increasing performance heterogeneity to benefit the modeling procedures. Group regression model results for F1, F2 and IF each identified a single predictor variable that accounted for 74.7, 98.6 and 81.6% explained variance (EV), respectively. Single-subject predictors and EV values varied and demonstrated a number of different strategies. The group models were not representative of any of the individual subjects\u27 performances and indicate that group models can describe a mythical average performer. These results suggest that researchers must be cautious when evaluating group performance patterns
Recruitment, growth and mortality of an Antarctic hexactinellid sponge, Anoxycalyx joubini.
Polar ecosystems are sensitive to climate forcing, and we often lack baselines to evaluate changes. Here we report a nearly 50-year study in which a sudden shift in the population dynamics of an ecologically important, structure-forming hexactinellid sponge, Anoxycalyx joubini was observed. This is the largest Antarctic sponge, with individuals growing over two meters tall. In order to investigate life history characteristics of Antarctic marine invertebrates, artificial substrata were deployed at a number of sites in the southern portion of the Ross Sea between 1967 and 1975. Over a 22-year period, no growth or settlement was recorded for A. joubini on these substrata; however, in 2004 and 2010, A. joubini was observed to have settled and grown to large sizes on some but not all artificial substrata. This single settlement and growth event correlates with a region-wide shift in phytoplankton productivity driven by the calving of a massive iceberg. We also report almost complete mortality of large sponges followed over 40 years. Given our warming global climate, similar system-wide changes are expected in the future
Simulating Windows-Based Cyber Attacks Using Live Virtual Machine Introspection
Static memory analysis has been proven a valuable technique for digital forensics. However, the memory capture technique halts the system causing the loss of important dynamic system data. As a result, live analysis techniques have emerged to complement static analysis. In this paper, a compiled memory analysis tool for virtualization (CMAT-V) is presented as a virtual machine introspection (VMI) utility to conduct live analysis during simulated cyber attacks. CMAT-V leverages static memory dump analysis techniques to provide live system state awareness. CMAT-V parses an arbitrary memory dump from a simulated guest operating system (OS) to extract user information, network usage, active process information and registry files. Unlike some VMI applications, CMAT-V bridges the semantic gap using derivation techniques. This provides increased operating system compatibility for current and future operating systems. This research demonstrates the usefulness of CMAT-V as a situational awareness tool during simulated cyber attacks and measures the overall performance of CMAT-V
The validity and reliability of a novel indoor player tracking system for use within wheelchair court sports
The aim of the current study was to investigate the validity and reliability of a radio- frequency based system for accurately tracking athlete movement within the wheelchair court sports. Four wheelchair specific tests were devised to assess the system during i) static measurements ii) incremental fixed speeds iii) peak speeds, and iv) multi-directional movements. During each test, three sampling frequencies (4, 8 & 16 Hz) were compared to a criterion method for distance, mean and peak speeds. Absolute static error remained between 0.19-0.32 m across the session. Distance values (test ii) showed greatest relative error in 4 Hz tags (1.3%), with significantly lower errors seen in higher frequency tags (< 1.0%). Relative peak speed errors of < 2.0% (test iii) were revealed across all sampling frequencies in relation to the criterion (4.00 ± 0.09 m·sˉ¹). Results showed 8 and 16 Hz sampling frequencies displayed the closest to criterion values, whilst intra-tag reliability never exceeded 2.0% coefficient of variation (% CV) during peak speed detection. Minimal relative distance errors (< 0.2%) were also seen across sampling frequencies (test iv). To conclude, the indoor tracking system is deemed an acceptable tool for tracking wheelchair court match-play using a tag frequency of 8 or 16 Hz
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