Earth science learning in SMALLab: A design experiment for mixed reality

Conversational technologies such as email, chat rooms, and blogs have made the transition from novel communication technologies to powerful tools for learning. Currently virtual worlds are undergoing the same transition. We argue that the next wave of innovation is at the level of the computer interface, and that mixed-reality environments offer important advantages over prior technologies. Thus, mixed reality is positioned to have a broad impact on the future of K-12 collaborative learning. We propose three design imperatives that arise from our ongoing work in this area grounded in research from the learning sciences and human-computer interaction. By way of example, we present one such platform, the Situated Multimedia Arts Learning Lab [SMALLab]. SMALLab is a mixed-reality environment that affords face-to-face interaction by colocated participants within a mediated space. We present a recent design experiment that involved the development of a new SMALLab learning scenario and a collaborative student participation framework for a 3-day intervention for 72 high school earth science students. We analyzed student and teacher exchanges from classroom sessions both during the intervention and during regular classroom instruction and found significant increases in the number of student-driven exchanges within SMALLab. We also found that students made significant achievement gains. We conclude that mixed reality can have a positive impact on collaborative learning and that it is poised for broad dissemination into mainstream K-12 contexts.     

Detroit River phosphorus loads: Anatomy of a binational watershed

As a result of increased harmful algal blooms and hypoxia in Lake Erie, the US and Canada revised their phosphorus loading targets under the 2012 Great Lakes Water Quality Agreement. The focus of this paper is the Detroit River and its watershed, a source of 25% of the total phosphorus (TP) load to Lake Erie. Its load declined 37% since 1998, due chiefly to improvements at the regional Great Lakes Water Authority Water Resource Recovery Facility (WRRF) in Detroit and phosphorus sequestered by zebra and quagga mussels in Lake Huron. In addition to the 54% of the load from Lake Huron, nonpoint sources contribute 57% of the TP load and 50% of the dissolved reactive phosphorus load, with the remaining balance from point sources. After Lake Huron, the largest source is the WRRF, which has already reduced its load by over 40%. Currently, loads from Lake Huron and further reductions from the WRRF are not part of the reduction strategy, therefore remaining watershed sources will need to decline by 72% to meet the Water Quality Agreement target - a daunting challenge. Because other urban sources are very small, most of the reduction would have to come from agriculturally-dominated lands. The most effective way to reduce those loads is to apply combinations of practices like cover crops, buffer strips, wetlands, and applying fertilizer below the soil surface on the lands with the highest phosphorus losses. However, our simulations suggest even extensive conservation on those lands may not be enough.     

Effect of multi‐branched PDLA additives on the mechanical and thermomechanical properties of blends with PLLA

Stereocomplex formation between poly(l ‐lactic acid) (PLLA) and poly(d ‐lactic acid) (PDLA) in the melt state was investigated and altered via the addition of multi‐branched poly(d ‐lactide) (PDLA) additives. Two different multi‐branched PDLA additives, a 3‐arm and 4‐arm star‐shaped polymeric structure, were synthesized as potential heat resistance modifiers and incorporated into PLLA at 5, 10, and 20 (w/w) through melt blending. Mechanical and thermomechanical properties of these blends were compared with linear poly(l ‐lactide) (PLLA) as well as with blends formed by the addition of two linear PDLA analogs that had similar molecular weights to their branched counterparts. Blends with linear PDLA additives exhibited two distinct melting peaks at 170–180°C and 200–250°C which implied that two distinct crystalline domains were present, that of the homopolymer and that of the stereocomplex, the more stable crystalline structure formed by the co‐crystallization of both d ‐ and l ‐lactide enantiomers. In contrast, blends of PLLA with multi‐branched PDLA formed a single broad melting peak indicative of mainly formation of the stereocomplex, behavior which was confirmed by X‐ray diffraction (XRD) analysis. The heat deflection temperature determined by thermal mechanical analysis was improved for all blends compared to neat PLLA, with increases of up to180°C for 20% addition of the 3‐arm PLLA additive. Rheological properties of the blends, as characterized by complex viscosity (η*), remained stable over a wide temperature range. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 132, 42858.     

DisplaySearch：宏基收购后的挣扎

Display Search新一季度笔记本市场的销售量及前景预测的研究报告指出：宏基在收购了Gateway和Packard Bell后似乎进行着一番挣扎。     

Scoping Antifungal Activities of Various Forms of Chitosan Oligomers and Their Potential Fixation in Wood

Chitosan oligomers （average Dp-4） are known for their antifungal activity and wood decay resistance. These oligomers are susceptible to moisture, and promote yeast growth upon air exposure after a sufficient length of time. Chitosan oligomers of three different states viz. completely dried, freshly prepared and highly viscous form, were prepared to compare their in-vitro antifungal activities against three brown-rot fungi, two sapstain and one mould fungus using agar nutrient medium. Additionally, a mixture of chitosan oligomers and boric acid was used for wood treatment. The nutrient medium bioassay results show that all states of chitosan oligomers inhibited the growth of tested basidiomycetes fungi, but not sapstain and mould fungi. Subsequently, wood decay results confirm antifungal activity of chitosan oligomers plus boron against basidiomycetes, but highlighted their leachability upon water exposure.     

Near-death experiences: Out of body and out of mind?

Comments on the original article, "Implications of near-death experiences for a post-materialist psychology," by B. Greyson (see record 2010-03251-005). Greyson (2010) has argued that complex consciousness (i.e., near-death experiences, or NDEs) under conditions such as cardiac arrest and general anesthesia challenge “materialist reductionism” and require a revised psychology anchored in 21st-century quantum physics that includes consciousness in its conceptual formulation. Unfortunately, Greyson fails to specify how quantum mechanics or a holistic approach can (a) enlighten our understanding of NDEs and (b) pave a foundation for a “new scientific conceptualization of the interface between mind and brain (Greyson, 2010, p. 43).” We agree with Greyson that NDEs are fascinating phenomena, and we further recognize that quantum mechanics undergirds chemistry, and so surely plays some as-yet- undefined role in mental processes. However, we sharply disagree that it is necessary to “expand models of the mind” on the basis of quantum mechanics “before we can progress in our understanding of consciousness and the brain (Greyson, 2010, p. 43).” We do not wish to duel with Greyson regarding if and when the brain is “completely disabled” during NDEs, but instead argue that the future is bright for understanding NDEs in terms of the everyday workings of the brain, and suggest important avenues of inquiry. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Influence of sampling depth on Escherichia coli concentrations in beach monitoring

While the US Environmental Protection Agency's (EPA) Beaches Environmental Assessment and Coastal Health (BEACH) Act requires coastal and Great Lakes’ states to implement plans for monitoring bacterial contamination of recreational beach water, exactly how this monitoring should occur has not been regulated. This study examined differences in concentration of Escherichia coli in water collected from different depths and from different horizontal locations across the beach. E. coli concentrations were significantly different (p<0.05), when water from different depths was compared. Sampling water at depths of 30, 60, and 120 cm resulted in significantly lower E. coli concentrations as depth increased. Had the State of Wisconsin chosen to collect beach water monitoring samples at a shallower or deeper depth, numbers of beach closures and the potential risk to public health would have changed substantially. These data imply that a revised and standardized protocol for monitoring beach water should be adopted by all states of a monitoring region to better compare microbial contamination of beaches and protect public health.     

Seasonal and clonal variations in technological and thermal properties of raw Hevea natural rubber

This study was undertaken over a 10‐month period under environmental conditions within the state of Mato Grosso, Brazil, to evaluate the causes of variation in the technological and thermal properties of raw natural rubber (NR) from different clones of Hevea brasiliensis (GT 1, PR 255, FX 3864, and RRIM 600). These clones were chosen to represent good clones available in Brazil. The technological properties of raw NR were evaluated in terms of their dry rubber content (DRC), Wallace plasticity, plasticity retention index (PRI), and Mooney viscosity. The thermal performance was evaluated with the thermogravimetry (TG)/differential thermogravimetry (DTG) technique. There were significant variations (p < 0.01 and p < 0.05) between clones and tappings for all technological properties, except for the percentage DRC among the clones. Of the clones studied, clone PR 255 presented the highest sensitivity to thermooxidation, as measured by its PRI value. The clone type and period of the year did not significantly influence the thermal behavior (TG/DTG under a nitrogen atmosphere) among the four clones evaluated. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

The corrosion performance of magnesium alloy AM-SC1 in automotive engine block applications

The magnesium alloy AM-SC1 has been developed as a creep-resistant automotive engine block material. This paper outlines its corrosion performance under laboratory test conditions, considering corrosion on both the external and internal surfaces. This study found that AM-SC1 has a corrosion performance comparable to AZ91 when subjected to an aggressive salt-spray environment or in galvanic-coupling environments. This article further demonstrates that, with the appropriate selection of a commercially available engine coolant, the internal corrosion of AM-SC1 can be maintained at a tolerable level. In addition, internal corrosion resistance can be significantly improved by the addition of fluorides to the coolant solution. It is concluded that AM-SC1 can be successfully used in an engine environment provided that some simple corrosion-prevention strategies are adopted. For more information, contact Guangling Song, University of Queensland, Brisbane, Australia; +61 7 3365 4197; fax +61 7 3365 3888; e-mail g.song@minmet.uq.edu.au.