Prediction of Eighth-Grade Achievement at Moxee Central School Using Metropolitan Achievement Test Scores from Early Elementary Grades

The main purpose of this study was to determine the relationship between the grade equivalent scores of the second, third and fourth grades of the Metropolitan Achievement Tests (MAT) and the eighth grade scores of the same MST test for use in predicting success in subsequent achievement tests as found on file at the Moxee High School

Sources and pathways of trace elements in urban environments: A multielemental qualitative approach

A geochemical model of an urban environment is presented in which multielemental tracers are used to characterise the circulation of trace elements in particulate matter_atmospheric aerosol, street dust and urban soil, within a city

Issues in Assessing Environmental Exposures to Manufactured Nanomaterials

Manufactured nanomaterials (MNs) are commonly considered to be commercial products possessing at least one dimension in the size range of 10−9 m to 10−7 m. As particles in this size range represent the smaller fraction of colloidal particles characterized by dimensions of 10−9 m to 10−6 m, they differ from both molecular species and bulk particulate matter in the sense that they are unlikely to exhibit significant settling under normal gravitational conditions and they are also likely to exhibit significantly diminished diffusivities (when compared to truly dissolved species) in environmental media. As air/water, air/soil, and water/soil intermedium transport is governed by diffusive processes in the absence of significant gravitational and inertial impaction processes in environmental systems, models of MN environmental intermedium transport behavior will likely require an emphasis on kinetic approaches. This review focuses on the likely environmental fate and transport of MNs in atmospheric and aquatic systems. Should significant atmospheric MNs emission occur, previous observations suggest that MNs may likely exhibit an atmospheric residence time of ten to twenty days. Moreover, while atmospheric MN aggregates in a size range of 10−7 m to 10−6 m will likely be most mobile, they are least likely to deposit in the human respiratory system. An examination of various procedures including the Derjaguin-Landau-Verwey-Overbeek (DLVO) theory of colloidal particle suspension stability in water indicates that more sophisticated approaches may be necessary in order to develop aquatic exposure models of acceptable uncertainty. In addition, concepts such as Critical Coagulation Concentrations and Critical Zeta Potentials may prove to be quite useful in environmental aquatic exposure assessments

PHOTOCHEMISTRY IN TERRESTRIAL EXOPLANET ATMOSPHERES. II. H₂S AND SO₂ PHOTOCHEMISTRY IN ANOXIC ATMOSPHERES

Sulfur gases are common components in the volcanic and biological emission on Earth, and are expected to be important input gases for atmospheres on terrestrial exoplanets. We study the atmospheric composition and the spectra of terrestrial exoplanets with sulfur compounds (i.e., H₂S and SO₂) emitted from their surfaces. We use a comprehensive one-dimensional photochemistry model and radiative transfer model to investigate the sulfur chemistry in atmospheres ranging from reducing to oxidizing. The most important finding is that both H₂S and SO₂ are chemically short-lived in virtually all types of atmospheres on terrestrial exoplanets, based on models of H₂, N₂, and CO₂ atmospheres. This implies that direct detection of surface sulfur emission is unlikely, as their surface emission rates need to be extremely high (>1000 times Earth's volcanic sulfur emission) for these gases to build up to a detectable level. We also find that sulfur compounds emitted from the surface lead to photochemical formation of elemental sulfur and sulfuric acid in the atmosphere, which would condense to form aerosols if saturated. For terrestrial exoplanets in the habitable zone of Sun-like stars or M stars, Earth-like sulfur emission rates result in optically thick haze composed of elemental sulfur in reducing H₂-dominated atmospheres for a wide range of particle diameters (0.1-1 μm), which is assumed as a free parameter in our simulations. In oxidized atmospheres composed of N₂ and CO₂, optically thick haze, composed of elemental sulfur aerosols (S₈) or sulfuric acid aerosols (H₂SO₄), will form if the surface sulfur emission is two orders of magnitude more than the volcanic sulfur emission of Earth. Although direct detection of H₂S and SO₂ by their spectral features is unlikely, their emission might be inferred by observing aerosol-related features in reflected light with future generation space telescopes.United States. National Aeronautics and Space Administration (NASA Earth and Space Science Fellowship (NESSF / NNX11AP47H

Deposition velocity of phosphorus-containing particles over southern Lake Huron, April-October, 1975

Total mass, phosphorus concentration and the size distribution of phosphorus-containing particles were determined. Samples were collected aboard the R/V Roger R. Simons and at eleven land-based stations from April to October, 1975. Based on cross-lake mass and phosphorus concentration gradients, size distribution and vertical profiles, a mixing box model was used to determine a deposition velocity for phosphorus-containing particles of 0.57cm s-1.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/23709/1/0000681.pd

Model predictions and a summary of dry deposition velocity data

Literature values of independent measurements of dry deposition velocities are summarized as a function of particle diameter and gas speciation. In most of the experiments reported in the literature, there are uncertainties that have hindered the development of general predictive deposition velocity models. However, one model (Sehmel and Hodgson, 1978) offers a more useful approach for predicting particle dry deposition velocities as a function of particle diameter, friction velocity, aerodynamic surface roughness, and particle density