An EPROM-based function generator

A circuit is described to produce arbitrary time-dependent voltage functions derived from digital information stored in EPROMs. While this circuit is designed to be used as a modulator of the microwave pump source or a solid state low noise maser, it can be readily adapted for other applications

Investigation of a 2-Colour Undulator FEL Using Puffin

Initial studies of a 2-colour FEL amplifier using one monoenergetic electron beam are presented. The interaction is modelled using the unaveraged, broadband FEL code Puffin. A series of undulator modules are tuned to generate two resonant frequencies along the FEL interaction and a self-consistent 2-colour FEL interaction at widely spaced non-harmonic wavelengths at 1nm and 2.4nm is demonstrated.Comment: Submitted to The 35th International Free-Electron Laser Conference, Manhattan, New York (2013

A Mixed Method Investigation of Industry Recognized Credentials and Academic Achievement Among Urban Schools in the State of Missouri

The purpose of this study was to gather the effectiveness of the Industry Recognized Credentials in preparing Career and Technical Education students’ postsecondary opportunities. This study sought to explore if students’ exposure to Career and Technical Education (CTE) programing and attainment of Industry Recognized Credentials leads to positive postsecondary placement for Kansas City Public High School students. The researcher collected data from the 2018, 2019, 2020, and 2021 school years. The researcher conducted a t-Test for difference in proportions, and the data revealed that the percentage of graduates attaining IRC for 2020-2021 was significantly higher than the previous years. The data showed a significant enrollment drop with no recovery in the next three academic years. The results from the survey data indicated that 72.5% of students planned to attend a two-year or four-year institution following graduation. The survey results revealed that 64.71% of the student respondents stated they were familiar with the Industry Recognized Credentials offered within the KCPS. The results from the focus group showed that students across the district were somewhat familiar with IRCs. Some respondents believed that the CTE program was designed only for manual jobs within the skilled trade areas, such as construction, trade, and auto technician. They were unaware the program could lead to college, as well as careers

Educational Groupings In The Middle School Science Classroom

Grouping students for learning has historically been debated among educational professionals. Twenty-first century skills encourage students to work together within their classrooms in preparation for future careers. Adopting Next Generation Science Standards (NGSS) has required educators to encourage collaboration among students for science learning. Understanding the implications of student groupings and differentiated instructional strategies on learning requires an important conversation for educators who strive to support all learners needs sufficiently and prepare them for their future. This qualitative study examines and describes the perceptions of teachers regarding the role of educational student groupings on student learning of science concepts. Ten middle school science teachers participated in one-to-one interviews to gather data. Results indicate teachers group students with a purpose to collectively learn in a collaborative environment as well as a way to maximum their time and resources. Grouping was found to be most efficient when students were working together cooperatively as engaged participants, free from behavioral distractions and supported with special education staff when needed. NGSS influenced classroom instruction by aligning curricular standards and introducing a high level of inquiry, collaboration and twenty-first century skills. These findings support the need for educational grouping professional development for science teachers to strengthen their understanding and practice within the classroom. This study’s findings informs teachers and school leaders as they strive to respond to requirements for educational groupings outlined by Next Generation Science Standards and 21st century skills

A preliminary report on work conducted in 1985 to evaluate Plantago ovata as a potential crop in the Ord River irrigation area

This paper reports on the first year of a 3 year programme aimed at developing P. ovata as a crop in the Ord River Irrigation Area (O.R.I.A.) of Kimberley region of Western Australia. The data from one year of trials indicate that Plantago ovata is highly suited to mechanisation and the Ord River Irrigation Area (ORIA). Machine harvested yields of up to 1.2 t/ha off 0.12 ha were achieved (after cleaning). The maximum hand harvested yield was 2.1 t/ha, 60 per cent higher than any other published value. Cununurra clays proved the best soil type for growth of the crop and this corresponds with an underutilised, developed resource of 14,000 ha

An extended model of the quantum free-electron laser

Previous models of the quantum regime of operation of the Free Electron Laser (QFEL) have performed an averaging and the application of periodic boundary conditions to the coupled Maxwell - Schrodinger equations over short, resonant wavelength intervals of the interaction. Here, an extended, one-dimensional model of the QFEL interaction is presented in the absence of any such averaging or application of periodic boundary conditions, the absence of the latter allowing electron diffusion processes to be modeled throughout the pulse. The model is used to investigate how both the steady-state (CW) and pulsed regimes of QFEL operation are affected. In the steady-state regime it is found that the electrons are confined to evolve as a 2-level system, similar to the previous QFEL models. In the pulsed regime Coherent Spontaneous Emission (CSE) due to the shape of the electron pulse current distribution is shown to be present in the QFEL regime for the first time. However, unlike the classical case, CSE in the QFEL is damped by the effects of quantum diffusion of the electron wavefunction. Electron recoil from the QFEL interaction can also cause a diffusive drift between the recoiled and non-recoiled parts of the electron pulse wavefunction, effectively removing the recoiled part from the primary electron-radiation interaction.Comment: Submitted to Optics Expres

Age at quitting smoking as a predictor of risk of cardiovascular disease incidence independent of smoking status, time since quitting and pack-years

BACKGROUND Risk prediction for CVD events has been shown to vary according to current smoking status, pack-years smoked over a lifetime, time since quitting and age at quitting. The latter two are closely and inversely related. It is not known whether the age at which one quits smoking is an additional important predictor of CVD events. The aim of this study was to determine whether the risk of CVD events varied according to age at quitting after taking into account current smoking status, lifetime pack-years smoked and time since quitting. FINDINGS We used the Cox proportional hazards model to evaluate the risk of developing a first CVD event for a cohort of participants in the Framingham Offspring Heart Study who attended the fourth examination between ages 30 and 74 years and were free of CVD. Those who quit before the median age of 37 years had a risk of CVD incidence similar to those who were never smokers. The incorporation of age at quitting in the smoking variable resulted in better prediction than the model which had a simple current smoker/non-smoker measure and the one that incorporated both time since quitting and pack-years. These models demonstrated good discrimination, calibration and global fit. The risk among those quitting more than 5 years prior to the baseline exam and those whose age at quitting was prior to 44 years was similar to the risk among never smokers. However, the risk among those quitting less than 5 years prior to the baseline exam and those who continued to smoke until 44 years of age (or beyond) was two and a half times higher than that of never smokers. CONCLUSIONS Age at quitting improves the prediction of risk of CVD incidence even after other smoking measures are taken into account. The clinical benefit of adding age at quitting to the model with other smoking measures may be greater than the associated costs. Thus, age at quitting should be considered in addition to smoking status, time since quitting and pack-years when counselling individuals about their cardiovascular risk.This research was supported by an NHMRC health services research grant (no. 465130), an NHMRC/NHF PhD scholarship and a Vichealth Fellowship

Vibrational frequencies and tuning of the African mbira

The acoustic spectrum of the mbira, a musical instrument from Africa that produces sound by the vibration of cantilevered metal rods, has been measured. It is found that the most prominent overtones present in the spectrum have frequencies that are approximately 5 and 14 times the lowest frequency. A finite-element model of the vibration of the key that takes into account the acoustic radiation efficiency of the various normal modes reveals that the far-field power spectrum is dominated by modes involving predominately transverse motion of the key. Modes involving longitudinal motion do not radiate efficiently, and therefore contribute little to the sound produced. The high frequencies of the dominant overtones relative to the fundamental make it unlikely that the tunings of the mbira that are used by expert musicians are determined by matching the fundamental frequencies of the upper keys with the overtones of the lower keys