In this investigation, the acquisition of both functional and core content sight Words Was compared as replicated across three formats: direct massed trial instruction in a special education resource room, direct distributed trial instruction in a general education classroom, and embedded distributed trial instruction in a general education classroom. Four students With moderate disabilities across three age groups participated. During direct instructional trials, both functional and core content sight Words Were presented using a constant time delay procedure. During embedded trials, the students received instruction in the same manner as their peers Without disabilities (e.g., teacher lecture, Worksheets, activities). Although the results varied slightly across participants, there Were minimal differences in the acquisition and maintenance of both functional and core content sight Words across the three presentation formats.

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The roots of aquatic plants, including rice, release oxygen into the subsurface, precipitating reduced metals, such as iron (Fe) and manganese (Mn), as plaques that form on the surface of the roots. These plaques are a unique habitat for microorganisms and a hotspot for biogeochemical cycling, including the toxic trace metalloid arsenic (As). However, studying plaque deposition and mineral composition in this spatially and temporally heterogeneous environment is challenging, particularly in situ. Here, we describe a new technique for nondestructive and repeated rhizosphere sampling. We placed vinyl films that adhere Fe deposits from roots growing adjacent to the films into soil. The films were removed and replaced throughout plant growth and were characterized using a variety of spectroscopic (XRF imaging and Fe EXAFS) and microscopic (SEM and confocal) techniques. Fe deposits were most concentrated at lateral junctions and heterogeneity was apparent in the location and speciation of Fe-associated As in both pot and field studies. XRF imaging at multiple incident beam energies revealed that this As was mostly arsenate, although arsenite was present on the edge of the Fe deposit. Iron deposits were typically micron sized and consisted mostly of ferrihydrite, consistent with the data reported using conventional techniques. Moreover, Fe deposits were occupied by a variety of microorganisms. These films are a suitable technique to study a range of spatial and temporal questions regarding the biogeochemistry of aquatic plant roots.

Soils with seasonal or continuous water saturation are characterized by unique redoxrelated processes including Fe and Mn oxide reduction. Indicators of reduction in soils (IRIS) devices were created as low-cost, direct sensors of such reduced chemistry. Such IRIS devices are painted with oxides of Fe or Mn, inserted into the soil, and then removed after a period of time; once removed, the paint lost due to reductive dissolution of these oxides is used to indicate the presence, location, and/or intensity of reducing conditions. However, quantifying the paint removal using existing methods can be subjective and time consuming. Here, we describe the use of the IRIS Imager, an image analysis program that calculates removal of paint from IRIS films in L*a*b* color space (where L* is lightness, a* is red-green value, and b* is blueyellow value) by comparing the change in lightness between initial and final IRIS film images. Paint removal from films deployed in flooded rice (Oryza sativa L.) paddy soils were quantified using the IRIS Imager, the grid method, and chemical extractions of IRIS films. All three methods were suitable for quantification of paint removal, but the IRIS Imager provided additional statistics to assess heterogeneity in paint removal on individual films and a less subjective approach to quantifying Mn oxide paint removal when Fe oxidation on Mn films was present. This free software can be used with IRIS devices to reproducibly measure paint removal from Fe oxide and Mn oxide IRIS and Fe oxide precipitation on Mn oxide IRIS.Abbreviations: DCB, dithionite-citrate-bicarbonate; ICP-OES, inductively coupled plasma-optical emission spectrometry; IRIS, indicator of reduction in soils.

Indicators of reduction in soil (IRIS) devices are low-cost soil redox sensors coated with Fe or Mn oxides, which can be reductively dissolved from the device under suitable redox conditions. Removal of the metal oxide coating from the surface, leaving behind the white film, can be quantified and used as an indicator of reducing conditions in soils. Manganese IRIS, coated with birnessite, can also oxidize Fe(II), resulting in a color change from brown to orange that complicates the interpretation of coating removal. Here, we studied field-deployed Mn IRIS films where Fe oxidation was present to unravel the mechanisms of Mn oxidation of Fe(II) and the resulting minerals on the IRIS film surface. We observed reductions in the Mn average oxidation state when Fe precipitation was evident. Fe precipitation was primarily ferrihydrite (30−90%), but lepidocrocite and goethite were also detected, notably when the Mn average oxidation state decreased. The decrease in the average oxidation state of Mn was due to the adsorption of Mn(II) to the oxidized Fe and the precipitation of rhodochrosite (MnCO 3 ) on the film. The results were variable on small spatial scales (<1 mm), highlighting the suitability of IRIS in studying heterogeneous redox reactions in soil.Mn IRIS also provides a tool to bridge lab and field studies of the interactions between Mn oxides and reduced constituents.