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

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

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

Safe and sound: A longitudinal study of the sffects of a Sigma Theta Tau International membership-based mentoring program on job satisfaction and intention-to-stay in new BSN-prepared nurses

Session presented on Saturday, July 25, 2015: Purpose: Mentoring programs extending past two years are uncommon, and yet the stressors of nursing still result in significant turn over during this period of time. The impact of membership in the nursing society Sigma Theta Tau International (STTI) has not been studied regarding new graduate nurses\u27 transition to practice. This study proposes analysis of the impact of a two-year mentorship, with the additional supports available through STTI membership, and the opportunity of quarterly socialization with participant peers. Methods: Proposed is a nonprobability sample, mixed-method, longitudinal pilot research study, which aims to evaluate protege job satisfaction and intention-to-stay at their current employment throughout the first 24 months of professional nursing practice. These proteges will be offered a voluntary commitment to a 24-month-long partnership with experienced nurses. All dyads will be subject to a training and introduction day regarding expectations of the Safe and Sound Mentoring Program, and will be required to attend a minimum of six of the eight quarterly education, socialization, and interview days over the 24-month course of the mentorship program. The program utilizes the Academy of Medical-Surgical Nurses\u27 Mentoring program format as the framework. Results: (Proposed research) This is a proposed research study; components of the education and socialization days to augment the mentoring relationship are currently in development, therefore study results will not be discussed at this stage. As the mentoring project will be a collaborative study with two (2) STTI Chapters: Seattle, Washington, USA, and Brisbane, Australia regions, data and outcomes will be comparatively analyzed and results disseminated by the study authors. The study may help to determine whether a mentoring relationship in which new nurses have a constant ally with whom to discuss early-practice challenges is of benefit. This study may concurrently enhance the participants\u27 engagement with STTI, and become a STTI member benefit. Another potential contribution to current practice may include using a nationally-recognized academy\u27s (Academy of Medical-Surgical Nursing) mentoring program framework in conjunction with an international nursing society\u27s (Sigma Theta Tau International) human capital to enhance the success of new nurses. The ongoing international collaboration is a current benefit of STTI membership and fulfills part of the society\u27s mission. Conclusion: (Proposed research) All participants will respond to quantitative surveys sent electronically in a quarterly timeframe. Survey instruments include selected items from Laschinger\u27s Conditions of Work Effectiveness Questionnaire-II, the Organizational Commitment Scale (OCS), and TeamSTEPPS\u27 Teamwork Perception Questionnaire. New nurses will also respond to group interview questions on the quarterly meeting days, which will be audiotaped, transcribed, and coded for themes. Data analysis will use multivariate analysis of covariance (MANCOVA); testing will use the means of the multiple dyads to test for the difference in the two dependent variables: job satisfaction and intention-to-stay

Plutonium concentrations in airborne soil at Rocky Flats and Hanford determined during resuspension experiments

Plutonium resuspension results are summarized for experiments conducted by the author at Rocky Flats, onsite on the Hanford reservation, and for winds blowing from offsite onto the Hanford reservation near the Prosser barricade boundary. In each case, plutonium resuspension was shown by increased airborne plutonium concentrations as a function of either wind speed or as compared to fallout levels. All measured airborne concentrations were far below maximum permissible concentrations (MPC). Both plutonium and cesium concentrations on airborne soil were normalized by the quantity of airborne soil sampled. Airborne radionuclide concentrations in ..mu..Ci/g were related to published values for radionuclide concentrations on surface soils. For this ratio of radionuclide concentration per gram on airborne soil divided by that for ground surface soil, there are eight orders of magnitude uncertainty from 10/sup -4/ to 10/sup 4/. This uncertainty in the equality between plutonium concentrations per gram on airborne and surface soils is caused by only a fraction of the collected airborne soil being transported from offsite rather than all being resuspended from each study site and also by the great variabilities in surface contamination. Horizontal plutonium fluxes on airborne nonrespirable soils at all three sites were bracketed within the same four orders of magnitude from 10/sup -7/ to 10/sup -3/ ..mu..Ci/(m/sup 2/ day) for /sup 239/Pu and 10/sup -8/ to 10/sup -5/ ..mu..Ci/(m/sup 2/ day) for /sup 238/Pu. Airborne respirable /sup 239/Pu concentrations increased with wind speed for a southwest wind direction coming from offsite near the Hanford reservation Prosser barricade. Airborne plutonium fluxes on nonrespirable particles had isotopic ratios, /sup 240/Pu//sup 239/ /sup 240/Pu, similar to weapons grade plutonium rather than fallout plutonium

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

Turbophoresis in forced inhomogeneous turbulence

We show, by direct numerical simulations, that heavy inertial particles (characterized by Stokes number St) in inhomogeneously forced statistically stationary isothermal turbulent flows cluster at the minima of mean-square turbulent velocity. Two turbulent transport processes, turbophoresis and turbulent diffusion together determine the spatial distribution of the particles. If the turbulent diffusivity is assumed to scale with turbulent root-mean-square velocity, as is the case for homogeneous turbulence, the turbophoretic coefficient can be calculated. Indeed, for the above assumption, the non-dimensional product of the turbophoretic coefficient and the rms velocity is shown to increase with St for small St, reach a maxima for St ≈ 10 and decrease as ∼ St - 0. 33 for large St. © 2018, The Author(s).publishedVersio

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

Continuous record of microparticle concentration and size distribution in the central Greenland NGRIP ice core during the last glacial period

A novel laser microparticle detector used in conjunctionwith continuous sample melting has provided a more than 1500 mlong record of particle concentration and size distribution of theNGRIP ice core, covering continuously the period approx. from9.5-100kyr before present; measurements were at 1.65 m depthresolution, corresponding to approx. 35-200yr. Particleconcentration increased by a factor of 100 in the Last GlacialMaximum (LGM) compared to the Preboreal, and sharp variations ofconcentration occurred synchronously with rapid changes in thed18O temperature proxy. The lognormal mode μ of thevolume distribution shows clear systematic variations with smallermodes during warmer climates and coarser modes during colderperiods. We find μ ~ 1.7 μm diameter during LGM andμ ~ 1.3 μm during the Preboreal. On timescales belowseveral 100 years μ and the particle concentration exhibit acertain degree of independence present especially during warmperiods, when μ was also more variable. Using highlysimplifying considerations for the atmospheric transport anddeposition of particles we infer that (i) the observed changes ofμ in the ice largely reflect changes in the size of airborneparticles above the ice sheet and (ii) changes of μ areindicative of changes in long range atmospheric transport time.From the observed size changes we estimate shorter transit timesby roughly 25% during LGM compared to the Preboreal. Theassociated particle concentration increase from more efficientlong range transport is estimated to less than one order ofmagnitude

Transuranic resuspension

Characteristics of aged resuspension sources are more uncertain than those of new resuspension sources, which can be investigated using inert-particle controlled-tracer sources. Even though airborne concentrations are low, one aged uniform-area source which can be used for resuspension studies is the accumulated radionuclide fallout in the soil from stratospheric and tropospheric fallout debris. Airborne radionuclide concentrations from this source were investigated at convenient locations on the Hanford site. The objective is to summarize plutonium and americium resuspension research conducted by the Pacific Northwest Laboratory from 1977 to 1983. Airborne plutonium was determined at five sites in the Hanford area, and both plutonium and americium were determined at two Hanford sites. Airborne plutonium and americium were examined as a function of aerodynamic particle diameter, sampling height, wind speed increments, and wind direction increments. The following results are discussed: airborne radionuclide concentrations, ..mu..Ci/cm/sup 3/ of sampled air; radionuclide activity densities, ..mu..Ci/g of airborne solids; airborne plutonium fluxes, ..mu..Ci/(m/sup 2/ day); /sup 241/Am//sup 239 +240/Pu) activity ratios, (..mu..Ci /sup 241/Am)/(..mu..Ci/sup 239 +240/Pu); and airborne solid concentrations, ..mu..g/m/sup 3/ of sampled air. In addition, a relationship based on field data for aged plutonium sources at Bikini Atoll, the Hanford site, and Rocky Flats was developed to estimate the maximum expected plutonium activity density on airborne solids compared to activity densities for bulk surface-soil samples. As a result, it is possible to more accurately predict resuspension factor ranges as a function of the resuspension source activity densities. 31 references, 18 figures, 5 tables