Rural Elementary Administrators’ Views of High-Stakes Testing

This study examines how rural elementary school administrators perceive the effects of high-stakes testing in comparison to suburban and urban elementary administrators. High-stakes testing had a greater impact, both positively and negatively, on rural administrators than on their counterparts in suburban and urban schools. Specifically, the positive effects were that rural administrators were more motivated by the testing program to do a better job, found the test results more useful in assessing teachers, and found the test results more useful in meeting the academic needs of students. The negative effects were that rural administrators felt more pressure than urban administrators to improve test scores and found their school rating to more negatively affect their ability to attract high quality teachers than administrators in suburban schools

Voices from the Frontlines:Teachers' Perceptions of High-Stakes Testing

The purpose of this study was to investigate whether teachers perceived Florida’s high-stakes testing program to be taking public schools in the right direction. More importantly, we sought to understand why teachers perceived the tests to be taking schools in the right or wrong direction. Based on the survey results of 708 teachers, we categorized their concerns and praises of high-stakes testing into ten themes. Most of the teachers believed that the testing program was not taking schools in the right direction. They commented that the test was used improperly and that the one-time test scores were not an accurate assessment of students’ learning and development. In addition, they cited negative effects on the curriculum, teaching and learning, and student and teacher motivation. The positive effects cited were much fewer in number and included the fact that the testing held students, educators, and parents accountable for their actions. Interestingly, teachers were not opposed to accountability, but rather, opposed the manner in which it was currently implemented. Only by understanding these positive and negative effects of the testing program can policymakers hope to improve upon it. To this end, we discuss several implications of these findings, including: limiting the use of test scores, changing the school grading criteria, using alternative assessments, modifying the curriculum, and taking steps to reduce teaching to the test

Reducing grains/loss asymmetry: A virtual reality choice experiment (VRCE) valuing land use change

Recent research suggests that, in some situations, numeric information may lack the 'evaluability' of visual representations of the same data. In such cases, reliance upon numeric information exacerbates tendencies for survey respondents to rely upon heuristics rather than their underlying preferences in formulating responses. Adapting such insights to the field of non-market valuation, for certain environmental goods, information on increases or decreases in the numeric levels of an attributes may trigger reliance upon the loss aversion heuristic, leading to an exacerbation of the well know gains/loss asymmetry problem (Horowitz and McConnell, 2002). A split sample choice experiment (CE) is described in which standard approaches to conveying a land use change scenario (relying principally on numeric information) are contrasted with an alternative treatment in which objectively identical information is presented in visual form via virtual reality (VR) visualisations. A third treatment combines both formats. Results show that the gains/loss asymmetry is roughly twice as strong under a conventional numeric CE design than in the presence of visual information. The combined VRCE methodology developed in the paper therefore significantly ameliorates this pervasive anomaly and, we contend, represents an exciting prospect for the incorporation of complex real world environments within economic analyses

Spatial selection and inheritance: applying evolutionary concepts to population dynamics in heterogeneous space.

Organisms in highly suitable sites generally produce more offspring, and offspring can inherit this suitability by not dispersing far. This combination of spatial selection and spatial inheritance acts to bias the distribution of organisms toward suitable sites and thereby increase mean fitness (i.e., per capita population increase). Thus, population growth rates in heterogeneous space change over time by a process conceptually analogous to evolution by natural selection, opening avenues for theoretical cross-pollination between evolutionary biology and ecology. We operationally define spatial inheritance and spatial selective differential and then combine these two factors in a modification of the breeder\u27s equation, derived from simple models of population growth in heterogeneous space. The modified breeder\u27s equation yields a conservative criterion for persistence in hostile environments estimable from field measurements. We apply this framework for understanding gypsy moth population persistence amidst abundant predators and find that the predictions of the modified breeder\u27s equation match initial changes in population growth rate in independent simulation output. The analogy between spatial dynamics and natural selection conceptually links ecology and evolution, provides a spatially implicit framework for modeling spatial population dynamics, and represents an important null model for studying habitat selection

Limited Dispersal and Heterogeneous Predation Risk Synergistically Enhance Persistence of Rare Prey

White-footed mice prey on gypsy moth pupae while foraging for other, more abundant food. Mice appear capable of locally extirpating moths since mice exert high predation pressure on sparse pupae and are numerically decoupled from moth populations. Nevertheless, during 23 years of monitoring, moths persisted at scales .1 ha despite frequent extinctions at smaller spatial scales. We hypothesized that spatially heterogeneous intensity in mouse foraging and/or limited moth dispersal might allow moth persistence. Using a spatially explicit, individual-based, empirically parameterized model, we show that neither spatially heterogeneous predation by mice, nor limited moth dispersal alone allows moth persistence at typical mouse densities. However, synergy between both factors allows moth population persistence at naturally occurring mouse densities. For example, in models with 40 mice/ha, both limited moth dispersal with spatially homogeneous predation risk and spatially heterogeneous predation risk with unlimited moth dispersal had a 0% chance of moth persistence, but the combination of limited dispersal and heterogeneous predation risk resulted in a ~75% chance of moth persistence. Furthermore, both for limited moth dispersal with spatially homogeneous predation risk and for spatially heterogeneous predation risk with unlimited moth dispersal, moth persistence was only guaranteed at very low mouse densities, while the combination of limited moth dispersal with heterogeneous predation guaranteed moth persistence within a broad range of mouse densities. The findings illustrate a novel mechanism of ‘‘spatial selection and satiation’’ that can enhance rare species persistence under intense incidental predation by generalist predators

Gene expression profiling of bone cells on smooth and rough titanium surfaces

Titanium (Ti) and Ti alloys are widely used as dental and orthopaedic implants, but the effects of the surface characteristics of these materials on the response of cells and target tissues is not well understood. The present study has therefore examined the effects of a rough Ti (RT) and a smooth Ti (ST) surface on human bone cells in vitro. Scanning electron microscopy showed attachment and spreading of cells on both surfaces. Expression profiling using ATLAS™ gene arrays showed marked differences in gene responses after 3 h of culture. A number of osteoblast genes were identified as "roughness response" genes on the basis of changes in expression on the RT compared with the ST surfaces. The surface roughness of Ti was thus found to have a profound effect on the profile of genes expressed by the bone cells, and suggests that improvements in the biological activity and possibly the clinical efficacy of these materials could be achieved by selective regulation of gene expression mediated by controlled modification of Ti surface

Quantifying a Dynamic Risk Landscape: Heterogeneous Predator Activity and Implications for Prey Persistence

Spatial heterogeneity in predation risk can ameliorate impacts on prey populations, particularly for prey of generalists. Spatially heterogeneous risk implies the existence of refugia, and the spatial scale of those refugia and their persistence over time affect whether prey can avoid predation by aggregating therein. Our objective was to quantify the magnitude, spatial scale, and temporal persistence of heterogeneity in risk of predation by white-footed mice (Peromyscus leucopus), an abundant generalist predator of gypsy moths (Lymantria dispar) and songbirds. We used track plates to measure white-footed mouse activity at .170 trees in each of three forest plots in upstate New York during summers of 2003–2005. We quantified the mean and coefficient of variation of track activity among trees by fitting the beta-binomial distribution to data from each plot and study period. We measured temporal persistence by disattenuated autocorrelation, and spatial scale by fitting exponential variograms. Mice were much less abundant in 2005 than the other two years, leading to lower overall track activity but higher coefficient of variation among trees. Mouse track activity at individual trees was positively autocorrelated between monthly study periods in 2003 and 2004, and even between the two years, whereas temporal autocorrelation in 2005 was much weaker. Track activity showed positive spatial autocorrelation over lag distances from ;30 to .1000 m. These findings indicate that mouse activity, and hence risk to their prey, varies substantially in space at spatial and temporal scales that appear responsive to mouse population dynamics. The spatial scale and temporal persistence of that variation imply that prey may benefit from returning to, or failing to disperse from, refugia

Use of Track Plates to Quantify Predation Risk at Small Spatial Scales

Spatial heterogeneity in risk is a critical component of predator-prey interactions. However, at small spatial scales, it is difficult to quantify predation risk without altering it. We used track plates to measure local predation risk created by white-footed mouse (Peromyscus leucopus) foraging activity on oak-forest plots in Millbrook, New York. Live gypsy moth pupae (Lymantria dispar) were placed at 2 heights on trees and monitored for predation. Pupae deployed on trees visited by mice were more likely to be eaten than those on trees not visited. Logistic regression indicated that predation rates on gypsy moth pupae were positively correlated with track activity, indicating that areas of concentrated mouse activity were areas of heightened risk for gypsy moths. Survival of individual oat grains placed on and 50 cm from track plates were not statistically different, indicating that mice exhibited no detectable behavioral reaction toward track plates. We conclude that track plates offer an economical and reliable means of quantifying local risk of attack by terrestrial mammals without substantially altering the spatial distribution of risk

Dust in the Photospheric Environment: Unified Cloudy Models of M, L, and T Dwarfs

We address the problem of how dust forms and how it could be sustained in the static photospheres of cool dwarfs for a long time. In the cool and dense gas, dust forms easily at the condensation temperature, T_cond, and the dust can be in detailed balance with the ambient gas so long as it remains smaller than the critical radius, r_cr. However, dust will grow larger and segregate from the gas when it will be larger than r_cr somewhere at the lower temperature, which we refer to as the critical temperature, T_cr. Then, the large dust grains will precipitate below the photosphere and only the small dust grains in the region of T_cr < T < T_cond can be sustained in the photosphere. Thus a dust cloud is formed. Incorporating the dust cloud, non-grey model photo- spheres in radiative-convective equilibrium are extended to T_eff as low as 800K. Observed colors and spectra of cool dwarfs can consistently be accounted for by a single grid of our cloudy models. This fact in turn can be regarded as supporting evidence for our basic assumption on the cloud formation.Comment: 50 pages with 14 postscript figures, to be published in Astrophys.