A comparison of under-age and regular-age children admitted to grade one in a suburban public school system.

Thesis (Ed.M.)--Boston Universit

The Virginia Iron, Coal, and Coke company and the growth and decline of Southern Appalachia’s iron industry: 1880-1930.

During the late nineteenth century, the penetration of industrial capitalism into southern Appalachia fundamentally altered the region’s economy. Historians have thoroughly studied this period’s coal and timber industries, but little scholarly attention has been paid to the iron industry. Iron production also made great strides in both output and scale as railroads and mining increased demand for iron products. The growth of Birmingham’s iron and steel industry has dominated the studies of iron that have been done, but between the 1880s and 1920s the iron industry of southwest Virginia and east Tennessee also were thoroughly modernized. The consolidation of the Virginia Iron, Coal, and Coke Company (VIC&CC) provides an excellent lens through which to observe this region’s industrial transformation. At the turn of the twentieth century the VIC&CC consolidated ownership and management of practically all of this region’s iron industry, and for decades management attempted to compete in the national iron market. This thesis examines the conditions that made the organization of the VIC&CC possible, the company’s attempt to profitably produce iron, and the activities of two businessmen (one a native of Virginia and prominent player in the state’s iron industry, and the other a New Yorker and seasoned veteran of Wall Street) that both played integral roles in this company’s business. During the studied timeframe, coal came to dominate the company’s interests over iron, and shortly after World War I, management dissolved its iron department. Although the iron industry ultimately failed, it still played a valuable role in southern Appalachia’s economic transformation

Saliz discolor: Prospects for phytoremediation of lead and polycyclic aromatic hydrocarbons

Members of the genus Salix, more commonly known as willows, are of great interest in the field of phytoremediation. Their ability to rapidly accumulate biomass, grow in disturbed conditions, aggressively seek water and development of extensive root systems are well documented – all highly desirable traits for phytoremediation, yet the remediation capabilities of most species remains unknown. The present study seeks to determine the ability of Salix discolor to remediate lead and polycyclic aromatic hydrocarbons (PAHs) – two of the most common pollutants in urban and industrial areas and which are often found in states of co-contamination. The ability of S. discolor to remove these contaminants from aqueous media was tested using a hydroponic experiment. The treatments consisted of an uncontaminated control, lead or PAH contamination and lead and PAH co-contamination. The concentration of the media was monitored weekly, and at the conclusion of the experiment the accumulation of the lead and PAHs in the roots, shoots and leaves of the plants will be analyzed using atomic absorption spectrometry and gas chromatography – mass spectrometry, respectively. Additionally, biomass accumulation will be recorded to determine the effects of contamination on the growth of the plants. Results are pending until the experiment has concluded. *Indicates faculty mentor

A Citizen Observatory Approach for Developing a Disease Outbreak Early Warning System

In health matters, early warning systems are timely surveillance systems that collect information on epidemic-prone diseases to trigger prompt public health interventions. However, these systems rarely apply statistical methods to detect changes in trends or sentinel events that would require intervention. Often, they rely on an in-depth review done by epidemiologists of the data coming in, which is rarely done systematically. This research introduced the use of ICT for collecting and analyzing citizen observations on disease trends and outbreaks. A citizen observatory ICT tool, which utilizes mobile and web features was developed. Data was collected on symptoms observed from diseases in four locations within Nairobi city. The system made use of mathematical models and outlier detection techniques to detect observations that deviated from the expected pattern in the dataset. New clusters were considered as outliers and the system flagged them as potential outbreaks. We clustered data using a K-Means algorithm and the Euclidean distance of each object from its corresponding cluster centre was obtained. From the results, the developed prototype was able to detect an outbreak of Flu and URTI diseases for the period of study. The proposed tool can therefore enhance the management of risks associated with disease outbreaks.  Keywords: Early Warning Systems, citizen observatory, health surveillance, Outlier Detection, Modeling disease outbreak

The BTC40 Survey for Quasars at 4.8 < z < 6

The BTC40 Survey for high-redshift quasars is a multicolor search using images obtained with the Big Throughput Camera (BTC) on the CTIO 4-m telescope in V, I, and z filters to search for quasars at redshifts of 4.8 < z < 6. The survey covers 40 sq. deg. in B, V, & I and 36 sq. deg. in z. Limiting magnitudes (3 sigma) reach to V = 24.6, I = 22.9 and z = 22.9. We used the (V-I) vs. (I-z) two-color diagram to select high-redshift quasar candidates from the objects classified as point sources in the imaging data. Follow-up spectroscopy with the AAT and CTIO 4-m telescopes of candidates having I < 21.5 has yielded two quasars with redshifts of z = 4.6 and z = 4.8 as well as four emission line galaxies with z = 0.6. Fainter candidates have been identified down to I = 22 for future spectroscopy on 8-m class telescopes.Comment: 27 pages, 8 figures; Accepted for publication in the Astronomical Journa

Environmental Dependence of the Fundamental Plane of Galaxy Clusters

Galaxy clusters approximate a planar (FP) distribution in a three-dimensional parameter space which can be characterized by optical luminosity, half-light radius, and X-ray luminosity. Using a high-quality catalog of cluster redshifts, we find the nearest neighbor cluster for those common to an FP study and the cluster catalog. Examining scatter about the FP, we find 99.2% confidence that it is dependent on nearest neighbor distance. Our study of X-Ray clusters finds that those with high central gas densities are systematically closer to neighbor clusters. If we combine results here with those of Fritsch and Buchert, we find an explanation for some of our previous conclusions: Clusters in close proximity to other clusters are more likely to have massive cooling flows because they are more relaxed and have higher central gas densities.Comment: Accepted for publication in Astrophysical Journal Letters. Moderate revisions, including more statistical analysis and discussion. Latex, 7 page

The coastal grasslands of Maputaland, South Africa : effects of fire and grazing on vegetation structure, diversity, and composition.

Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2007.A series of trials and investigations were implemented to address concerns surrounding the dynamics of the fire-climax wooded/edaphic grasslands within the iSimangaliso Wetland Park, northern KwaZulu-Natal, South Africa. The research problem surrounded inadequate historical evaluations of changes in vegetation structure, grasslands progressing to a woody dominated composition, and increases in Helichrysum kraussii (Curry bush). These were addressed as follows: Firstly, the recovery of vegetation in response to different periods of fire exclusion in different communities along a topographical gradient of a coastal dune area, was assessed over a two year period. Secondly, the regeneration after wildfire of the persistent, stress tolerant shrub H. kraussii, was studied on different catenal positions with differing fire exclusion periods and with and without defoliation of surrounding plant biomass in the coastal edaphic grasslands north of Manzengwenya, South Africa. Thirdly, aerial photography from 1937, 1975, and 2000 was georectified, digitised and analysed using a Geographic Information System to examine broad vegetation changes in response to different management regimes for a site on the Eastern Shores of Lake St Lucia and a site within the Tewate Wilderness Area. In the absence of fire, the coastal edaphic grasslands progressed to a closed canopied scrub forest within six years. An increase in fire exclusion period resulted in a decrease in species abundance, an increase in woody height, and a decrease in plant density. Richness increased initially but declined marginally with increased fire exclusion period. Higher lying east and west facing sites had a better veld condition index compared with bottom sites and had an increased response (vigour) to defoliation but were far more likely to succeed through to woody scrub forest. Woody plant biomass vigour was greater for west facing sites. Ordination of species composition across sites in response to fire exclusion and catenal position revealed greater similarities within exclusion periods than between. Bottom sites were more similar with similarity decreasing for east and west facing sites. Fire exclusion resulted in an initial increase in woody species and a subsequent increase in herbaceous species. iii Growth response of H. kraussii was unaffected by catenal position and fire exclusion period, whereas defoliation of surrounding grass tended to increase in size (P<0.05). Density and height for this species however increased with increasing fire exclusion. An increase in soil moisture negatively affected H. kraussii growth indicating susceptibility to high water tables. The number of other woody species establishing beneath H. kraussii may be due to changes in the transmission of light through the canopy where an increase in canopy diameter resulted in an increase of photosynthetically active radiation at the soil surface. The effects of fire on landscape change were investigated for the Eastern Shores and Tewate Wilderness Area, iSimangaliso Wetland Park, South Africa using aerial photography. Changes to historical disturbance regimes largely through active exclusion of fire resulted in the majority of the higher lying coastal grasslands changing to savanna scrub or closed canopied forest within 63 years on the Eastern Shores. The degree of fragmentation of these grasslands was greatly reduced within the Tewate Wilderness Area where disturbance regimes included greater frequencies of fire. Hygrophilous grasslands remained largely unaffected by woody encroachment but did not preclude woody species establishment indicating possible susceptibility during long drier periods. Frequent fires result in the maintained distribution of the higher grasslands. This vegetation type is a system which becomes resilient in response to fire, whereas in the absence of fire readily progresses to Dune Forest. The coastal grasslands above the high water table are therefore highly unstable and transformed easily in the absence of regular disturbance. It would appear that a threshold of approximately six years exists, after which substantial management intervention may be required to reverse the succession back to grassland. The growth of H. kraussii was unaffected by fire and remained persistent irrespective of fire exclusion period. An ability to attain size (height and canopy diameter) was limited with increased soil moisture but density was reduced through regular burning. Frequent fires are necessary to reduce density of H. kraussii and reduce the competitive advantage gained with age

Outsourcing Intensity and Ownership: Theory and Evidence from California General Care Hospitals

For-profit hospitals in California contract out services much more intensely than either public hospitals or private nonprofit hospitals. To explain why, we build a model in which the outsourcing decision is a trade-off between net revenues and some nonmonetary benefit to the manager, which we call “bias” in the manner of production. Since nonprofit firms must consume profits indirectly, they trade off differently than for-profit firms. This difference is exaggerated in services where nonmonetary benefits are particularly important but minimized when the firm is hit with a fixed-cost shock. We test these predictions in a panel of California hospitals, finding evidence for each. These results suggest that a model of public or nonprofit make-or-buy decisions should be more than a simple relabeling of a model derived in the for-profit context

Outsourcing Intensity and Ownership: Theory and Evidence from California General Care Hospitals

For-profit hospitals in California contract out services much more intensely than either public hospitals or private nonprofit hospitals. To explain why, we build a model in which the outsourcing decision is a trade-off between net revenues and some nonmonetary benefit to the manager, which we call “bias” in the manner of production. Since nonprofit firms must consume profits indirectly, they trade off differently than for-profit firms. This difference is exaggerated in services where nonmonetary benefits are particularly important but minimized when the firm is hit with a fixed-cost shock. We test these predictions in a panel of California hospitals, finding evidence for each. These results suggest that a model of public or nonprofit make-or-buy decisions should be more than a simple relabeling of a model derived in the for-profit context