A review of the research in testing in secondary school general science from 1938-1952 including nine reviews of standardized tests

Thesis (Ed.M.)--Boston Universit

Maine’s Oldest Historical Societies

This preface provides an overview of the material to be discussed in the issue

From Dark Matter to the Earth's Deep Interior: There and Back Again

This thesis is a two-way transfer of knowledge between cosmology and seismology, aiming to substantially advance imaging methods and uncertainty quantification in both fields. I develop a method using wavelets to simulate the uncertainty in a set of existing global seismic tomography images to assess the robustness of mantle plume-like structures. Several plumes are identified, including one that is rarely discussed in the seismological literature. I present a new classification of the most likely deep mantle plumes from my automated method, potentially resolving past discrepancies between deep mantle plumes inferred by visual analysis of tomography models and other geophysical data. Following on from this, I create new images of the upper-most mantle and their associated uncertainties using a sparsity-promoting wavelet prior and an advanced probabilistic inversion scheme. These new images exhibit the expected tectonic features such as plate boundaries and continental cratons. Importantly, the uncertainties obtained are physically reasonable and informative, in that they reflect the heterogenous data distribution and also highlight artefacts due to an incomplete forward model. These inversions are a first step towards building a fully probabilistic upper-mantle model in a sparse wavelet basis. I then apply the same advanced probabilistic method to the problem of full-sky cosmological mass-mapping. However, this is severely limited by the computational complexity of high-resolution spherical harmonic transforms. In response to this, I use, for the first time in cosmology, a trans-dimensional algorithm to build galaxy cluster-scale mass-maps. This new approach performs better than the standard mass-mapping method, with the added benefit that uncertainties are naturally recovered. With more accurate mass-maps and uncertainties, this method will be a valuable tool for cosmological inference with the new high-resolution data expected from upcoming galaxy surveys, potentially providing new insights into the interactions of dark matter particles in colliding galaxy cluster systems

A1_1 A Leak in Space

In the interest of risk management, it is important that we consider all possible eventualities that could endanger the crew of future manned spaceflights. In this paper, we derive the rate of loss of oxygen when a hole compromises a ship and determine how long a crew have to act before oxygen reaches critical levels. We find the relation, t = 2.8×10-3 V/A s, where V is the volume of the cabin, t is the time till critical levels are reached and A is the area of the exposed hole. We conclude that, for a reasonable V, the crew have a very limited amount of time to act. This makes it clear that the best solution is to compartmentalise a ship, as there is enough time vacate the area and seal off the leak

A1_3 Hydrogen Atom in One Dimension

We investigated the ground state energy of the hydrogen atom if it existed in a world with only one spatial dimension. Using variational principle, we found that the ground state energy of a 1D hydrogen atom is less than or equal to 0.17 eV

Cost Implication of Packaging and Labeling on Profitability of Bakery Firms in Ebonyi State, Nigeria

The food processing industry and their distributors are presently facing extra challenges and demands on how to provide the variety of foods that are expected from them by the consumers and still strive to remain profitable. The study aims to ascertain the cost effect of packaging and labeling on the profitability of bakery firms in Ebonyi State, Nigeria. The study adopted an ex-post facto research design. The data used was mainly time series data which are quantitative in nature and the ten year-data generated for the study was analyzed using multiple regressions. The Microsoft Excel spreadsheet was used to transform the data into its usable format for analyses and the Statistical Package for Social Sciences (SPSS) was employed for data analysis at 5% level of significance. The findings, however, revealed that the cost of packaging and labeling has no significant effect on the profitability of bakery firms in Ebonyi State, Nigeria. Notwithstanding the potential for packaging to successfully achieve marketing goals in bakery, it is recommended that managers should be mindful of the percentage of their operating costs that goes into packaging in order not to affect their profits negatively. Keywords: Bakery, Packaging, Labeling, Profitability

Atmospheric effects on testing and calibrating star tracking algorithms

Star trackers are usually considered to be the most accurate sensors, able to achieve a sub-arcminute precision. Star tracker algorithms are often tested and validated with simulated space views. Testing the algorithms with real space images is expensive as it requires implementing them on existing in-space star trackers, or launching new satellites. This study shows that those algorithms are usually performing poorly with groundbased sky pictures and that some adaptations are necessary to take into account the atmospheric effects. In order to tackle this issue, this study will start by implementing and testing two published Lost-In-Space algorithms with a simulated sensor to compare their performance against various noise sources. After comparing the space-based generated views with groundbased images, an adaptation for the aforementioned algorithms is proposed. In order to counter the effect of atmospheric extinction, the number of stars visible in the image is increased by modifying the field-of-view of the camera, the exposure time and estimating the experimental inter-star angular distance error. The idea is to match the star density used in the state-of-the-art algorithms in the experimental pictures. The modified algorithms are tested with the experimental images, and the adaptation process is validated with a good success rate

Calibration and testing strategies to correct atmospheric effects on star tracking algorithms

Star trackers are usually considered to be the most accurate sensors, able to achieve a sub-arcminute precision. Star tracker algorithms are often tested and validated with simulated space views. Testing the algorithms with real space images is expensive as it requires implementing them on existing in-space star trackers, or to launch new satellites. This study shows that those algorithms are usually performing poorly with ground-based sky pictures and that some adaptations are necessary to take into account the atmospheric effects. The adaptation of star tracking algorithms to ground pictures could ease the prototyping phase for new star trackers, or for ground-based and air-borne star trackers, without the need to buy specific testing simulators. In order to tackle this issue, this study will start by implementing and testing two published Lost-In-Space algorithms with a simulated sensor to compare their performance against various noise sources. After comparing the space-based generated views with ground-based images, an adaptation for the aforementioned algorithms is proposed. In order to counter the effect of atmospheric extinction, the number of stars visible in the image is increased by modifying the field-of-view of the camera, the exposure time and estimating the experimental inter-star angular distance error. The idea is to match the star density used in the state-of-the-art algorithms in the experimental pictures. The modified algorithms are tested with the experimental images, and the adaptation process is validated with a good success rate