The SAT Anomaly: Does Average Class Size Impact Average SAT Score?

Because the SAT has the potential to set the trajectory of students’ educational careers, the SAT is arguably the most important examination for most American high-schoolers. Considering the importance of the SAT examination, we sought to examine whether there is a relationship between average SAT scores with average high school class size per public school district. Using Georgia county-level data, our findings indicate that there is a minute and statistically insignificant correlation between average class size and average SAT score. Our results do show, however, that other variables such as median household income, average expenditure per pupil, and average educational attainment do have statistically significant correlations with average SAT score

Microdevices and Methods of Manufacture

Illustrative embodiments of microdevices and methods of manufacturing such microdevices are disclosed. In at least one illustrative embodiment, a method of manufacturing one or more microdevices may include forming a liquid dispersion containing cellulose nanocrystals (CNC), depositing the liquid dispersion containing the CNC on a substrate, drying the liquid dispersion containing the CNC to form a solid film on the substrate, where the liquid dispersion contains a sufficient concentration of CNC to form a continuous solid film having a controlled microstructure, and processing the solid film to form the one or more microdevices on the substrate

Microdevices and methods of manufacture

Illustrative embodiments of microdevices and methods of manufacturing such microdevices are disclosed. In at least one illustrative embodiment, one or more microdevices may be formed on a substrate, with each of the one or more microdevices comprising a body micromachined from a continuous film formed on the substrate, the continuous film having a controlled microstructure of cellulose nanocrystals (CNC)

Carbon Nanotube and Cellulose Nanocrystal Hybrid Films

The use of cellulose nanocrystals (CNC) in high performance coatings is attractive for micro-scale structures or device fabrication due to the anisotropic geometry, however CNC are insulating materials. Carbon nanotubes (CNT) are also rod-shaped nanomaterials that display high mechanical strength and electrical conductivity. The hydrophobic regions of surface-modified CNC can interact with hydrophobic CNT and aid in association between the two anisotropic nanomaterials. The long-range electrostatic repulsion of CNC plays a role in forming a stable CNT and CNC mixture dispersion in water, which is integral to forming a uniform hybrid film. At concentrations favorable for film formation, the multiwalled nanotubes + CNC mixture dispersion shows cellular network formation, indicating local phase separation, while the single-walled nanotube + CNC mixture dispersion shows schlieren texture, indicating liquid crystal mixture formation. Conductive CNT + CNC hybrid films (5–20 μm thick) were cast on glass microscope slides with and without shear by blade coating. The CNT + CNC hybrid films electrical conductivity increased with increasing CNT loadings and some anisotropy was observed with the sheared hybrid films, although to a lesser extent than what was anticipated. Percolation models were applied to model the hybrid film conductivity and correlate with the hybrid film microstructure

Demography and movements of Snail kites in Florida

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The Proportion of Snail Kites Attempting to Breed and the Number of Breeding Attempts per Year in Florida

During the breeding season of 1995 we monitored the proportion of adult and subadult Snail Kites (Rostrhamus sociabilis) attempting to breed and the number of breeding attempts using radio telemetry. Our sample consisted of 23 adults (14 females, 9 males) and 9 subadults for which we had data over the entire breeding season. All adults attempted to breed at least once with an observed average of 1.4 (± 0.6 SD) breeding attempts per individual. In contrast, only 3 (33%) of the subadults attempted to breed. Of the adults, 15 (65%) made one breeding attempt, 7 (30%) made two breeding attempts,and 1 (4%) attempted three times. Only one bird (4%) successfully raised two broods. Our data are consistent with previous reports that \u3e1 breeding attempt by Snail Kites in Florida is common during some years, although our estimate for 1995 was lower han previously reported estimates. A combination of our estimation procedures, definitions of a breeding attempt, and annual variability of this parameter probably account for the disparity between our data and previous reports

Analysis of County Level E-Government Implementations

This study examines the stages of development for county-level e-government implementations in the United States for 344 randomly selected websites. Population size, poverty levels and income levels were examined. Results indicate that most counties have some form of e-government but counties with smaller populations are more likely to have only an online presence with no citizen interaction

Snail Kite Nest Success and Water Levels : A Reply to Beissinger and Snyder

Beissinger and Snyder present a commentary on our recent paper on spatial and temporal variability in nest success of Snail Kites (Rostrhamus sociabilis) in Florida (Dreitz et al. 2001). Beissinger and Snyder reanalyze a subset of data presented in our original paper to show that water levels have a significant influence on nest success. To make their argument, the authors conduct separate analyses for 5 of the original 11 wetlands; including only those having the most data. We agree with Beissinger and Snyder that water levels can affect nest success in some areas or years, as we stated in Dreitz et al. (2001). However, the purpose of our original paper was to examine the influences of nest success over broad spatial and temporal scales. When viewed in this context, using a meta-analysis, water levels alone explain only a small amount of the observed variation in nest success. One of the advantages of using a meta-analysis is that it uses all of the available data to provide an indication of the overall magnitude of an effect, which can easily be misinterpreted when viewed in a narrower context of individual study sites. We discuss the management implication of these alternative perspectives on water levels in light of their effect on habitat quality and persistence

Spatial and Temporal Variability in Nest Success of Snail Kites in Florida : A Meta-Analysis

Nesting success of Snail Kites (Rostrhamus sociabilis) in Florida is highly variable among years and locations, and hydrology is the most frequently reported explanatory factor. We conducted a meta-analysis to evaluate the extent of spatial and temporal variability in nesting success, and explicitly tested for the effects of annual minimum water levels. Data were obtained from six independent studies spanning 22 years and 11 wetlands. Our results indicated there was substantial spatial and temporal variability in nest success and that annual minimum water level, either as a categorical or continuous response, was not a significant source of this variation. Our results do not imply that low water levels do not influence nest success. Rather, they indicate that the number of nests affected by low water conditions was quite low

Annual Survival of Snail Kites in Florida: Radio Telemetry versus Capture-Resighting Data

We estimated annual survival of Snail Kites (Rostrhamus sociabilis) in Florida using the Kaplan-Meier estimator with data from 271 radio-tagged birds over a three-year period and capture-recapture (resighting) models with data from 1,319 banded birds over a six-year period. We tested the hypothesis that survival differed among three age classes using both data sources. We tested additional hypotheses about spatial and temporal variation using a combination of data from radio telemetry and single- and multistrata capture-recapture models. Results from these data sets were similar in their indications of the sources of variation in survival, but they differed in some parameter estimates. Both data sources indicated that survival was higher for adults than for juveniles, but they did not support delineation of a subadult age class. Our data also indicated that survival differed among years and regions for juveniles but not for adults. Estimates of juvenile survival using radio telemetry data were higher than estimates using capture-recapture models for two of three years (1992 and 1993). Ancillary evidence based on censored birds indicated that some mortality of radio-tagged juveniles went undetected during those years, resulting in biased estimates. Thus, we have greater confidence in our estimates of juvenile survival using capture-recapture models. Precision of estimates reflected the number of parameters estimated and was surprisingly similar between radio telemetry and single-stratum capture-recapture models, given the substantial differences in sample sizes. Not having to estimate resighting probability likely offsets, to some degree, the smaller sample sizes from our radio telemetry data. Precision of capture-recapture models was lower using multistrata models where region-specific parameters were estimated than using single-stratum models, where spatial variation in parameters was not taken into account