The relation between interest and achievement in fourth grade reading

Thesis (Ed.M.)--Boston Universit

A study to ascertain what effect the study of homophones has on spelling achievement

Thesis (Ed.M.)--Boston Universit

A study to ascertain what effect the study of homophones has on spelling achievement

Thesis (Ed.M.)--Boston Universit

Comparative ecotoxicity of three polluted industrial soils for the Collembola Folsomia candida

We tried to quantify the ecotoxicity of three industrial soil samples contaminated by different metals, using the Collembolan Folsomia candida as a biological model and mortality, growth and reproduction as parameters. The observed ecotoxicities are rather normal for the first such soil sample (aluminum factory) but are high for the second sample (ore treatment) and relatively low for the third one (zinc factory) considering its high metal concentrations. For these last two soil samples, an unusual ecotoxicity plotting is observed: two high ecotoxicity recordings fit with a low and high percentage of polluted soil to non-polluted soil and noticeably lower ecotoxicity recordings are observed between them. Chemical analyses of metals in pore waters show that arsenic probably explains part of such an unusual ecotoxicity curve. Otherwise, mortality and growth of the animals are less sensitive parameters than reproduction. Our experiments show that the results of the ecotoxicological assays of polluted soils are complex and difficult to interpre

Classification cards applied to team and individual learning.

Thesis (Ed.M.)--Boston Universit

"All You Need is Love" - and What about Gender? Engendering Burton's Human Needs Theory

Ye

Rotating disk electrodes to assess river biofilm thickness and elasticity

The present study examined the relevance of an electrochemical method based on a rotating disk electrode (RDE) to assess river biofilm thickness and elasticity. An in situ colonisation experiment in the River Garonne (France) in August 2009 sought to obtain natural river biofilms exhibiting differentiated architecture. A constricted pipe providing two contrasted flow conditions (about 0.1 and 0.45 m s−1 in inflow and constricted sections respectively) and containing 24 RDE was immersed in the river for 21 days. Biofilm thickness and elasticity were quantified using an electrochemical assay on 7 and 21 days old RDE-grown biofilms (t7 and t21, respectively). Biofilm thickness was affected by colonisation length and flow conditions and ranged from 36 ± 15 μm (mean ± standard deviation, n = 6) in the fast flow section at t7 to 340 ± 140 μm (n = 3) in the slow flow section at t21. Comparing the electrochemical signal to stereomicroscopic estimates of biofilms thickness indicated that the method consistently allowed (i) to detect early biofilm colonisation in the river and (ii) to measure biofilm thickness of up to a few hundred μm. Biofilm elasticity, i.e. biofilm squeeze by hydrodynamic constraint, was significantly higher in the slow (1300 ± 480 μm rpm1/2, n = 8) than in the fast flow sections (790 ± 350 μm rpm1/2, n = 11). Diatom and bacterial density, and biofilm-covered RDE surface analyses (i) confirmed that microbial accrual resulted in biofilm formation on the RDE surface, and (ii) indicated that thickness and elasticity represent useful integrative parameters of biofilm architecture that could be measured on natural river assemblages using the proposed electrochemical method