1,239 research outputs found
Troubleshooting During a Language Class: Analysis of Classroom Discourse in First-Year Japanese as a Foreign Language Classrooms
Much of the existing empirical research on classroom discourse has been framed by the notion of the Initiation-Response-Feedback (IRF) sequence, but this very notion has been challenged by scholars as the IRF sequence may not be as productive as existing literature shows. This paper aims to contribute to the existing literature on classroom discourse on how teachers and students negotiate their interactions in the classroom in light of classroom management with a more fluid version of the IRF sequence. I analyzed three separate moments of classroom interaction in a Japanese as a Foreign Language (JFL) classroom at the university level in this paper, where the teachers and students are engaging in resolving an issue in class, which I use the generic term ‘troubleshooting’ to describe the interaction. The findings reveal that troubleshooting can happen at any point in time during class: mid-activity, transitioning between activities, or pre-activity. By showcasing these examples, we may be able to further examine the fluidity of the classroom discourse, as well as how participants experience the classroom
Small Community Water Systems Have the Highest Prevalence of Mn in Drinking Water in California, USA
Manganese (Mn) is currently regulated as a secondary contaminant in California, USA; however, recent revisions of the World Health Organization drinking water guidelines have increased regulatory attention of Mn in drinking water due to increasing reports of neurotoxic effects in infants and children. In this study, Mn concentrations reported to California’s Safe Drinking Water Information System were used to estimate the potentially exposed population within California based on system size. We estimate that between 2011 and 2021, over 525,000 users in areas with reported Mn data are potentially exposed to Mn concentrations exceeding the WHO health-based guideline (80 μg L–1), and over 34,000 users are potentially exposed to Mn concentrations exceeding the U.S. Environmental Protection Agency health-advisory limit (300 μg L–1). Water treatment significantly decreased Mn concentrations compared to intake concentrations for all system sizes. However, smaller water systems have a wider range and a higher skew of Mn concentrations in finished water than larger systems. Additionally, higher Mn concentrations were found in systems above the maximum contaminant levels for chromium and arsenic. The treatment of these primary contaminants appears to also remove Mn. Lastly, data missingness remains a barrier to accurately assess public exposure to Mn in very small, small, and medium community water system-delivered water
OSSOS VI. Striking Biases in the detection of large semimajor axis Trans-Neptunian Objects
The accumulating, but small, set of large semi-major axis trans-Neptunian
objects (TNOs) shows an apparent clustering in the orientations of their
orbits. This clustering must either be representative of the intrinsic
distribution of these TNOs, or else arise as a result of observation biases
and/or statistically expected variations for such a small set of detected
objects. The clustered TNOs were detected across different and independent
surveys, which has led to claims that the detections are therefore free of
observational bias. This apparent clustering has led to the so-called "Planet
9" hypothesis that a super-Earth currently resides in the distant solar system
and causes this clustering. The Outer Solar System Origins Survey (OSSOS) is a
large program that ran on the Canada-France-Hawaii Telescope from 2013--2017,
discovering more than 800 new TNOs. One of the primary design goals of OSSOS
was the careful determination of observational biases that would manifest
within the detected sample. We demonstrate the striking and non-intuitive
biases that exist for the detection of TNOs with large semi-major axes. The
eight large semi-major axis OSSOS detections are an independent dataset, of
comparable size to the conglomerate samples used in previous studies. We
conclude that the orbital distribution of the OSSOS sample is consistent with
being detected from a uniform underlying angular distribution.Comment: Accepted for publicatio
Inhibition of Chromium(III) Oxidation through Manganese(IV) Oxide Passivation and Iron(II) Abiotic Reduction
Manganese (Mn) oxides are strong oxidants that are ubiquitous in soils and can oxidize redox-active metals, including chromium (Cr). In soil environments, trivalent chromium (Cr(III)) is a benign, immobile micronutrient, whereas the hexavalent Cr(VI) form is present as a highly mobile, toxic chromate oxyanion. Although many studies have characterized the capacity of Mn(III/IV) oxides to oxidize Cr(III) to toxic Cr(VI), the oxidative capacity of Mn oxides in the presence of potentially passivating soil constituents, specifically reduced soluble iron (Fe(II)aq), remains unresolved. We hypothesized that chemical processes at redox interfaces, such as diffusion-limited environments within soil aggregates, can lead to decreased Cr(VI) production from Mn oxide-driven oxidation due to passivation by Fe(II)aq. A multichamber diffusion-limited reactor was used to simulate transport at soil redox interfaces and investigate the capacity of poorly crystalline and crystalline Mn oxides to oxidize solid Cr(III) minerals to Cr(VI) in the presence of Fe(II)aq. As predicted, Cr(VI) was produced through the Mn oxide-catalyzed oxidation of Cr(III) at a rate controlled by the solubility of Cr(OH)3. However, in the presence of Fe(II)aq, the concentration of aqueous Cr(VI) decreased as a function of the Fe(II)aq concentration, where high concentrations of Fe(II)aq completely inhibited Cr(VI) production, likely through both the passivation of the Mn oxide and the direct reduction of Cr(VI) by Fe(II). At both low (14 μM) and high (100 μM) Fe(II)aq concentrations, the iron oxide minerals hematite (Fe2O3) and goethite (α-FeOOH) were associated with the Mn oxides, which can cause surface passivation, a likely role that decreases Cr(III) oxidation. Additionally, the Cr(III) oxidation rate decreased with increasing crystallinity of the Mn oxides whether or not Fe(II) was present
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Linking extreme precipitation in Southeast Asia to equatorial waves
Equatorially trapped waves, such as Kelvin Waves, Equatorial Rossby Waves and Westward-moving Mixed Rossby-Gravity (WMRG) Waves, play a major role in organizing tropical convection on synoptic to sub-seasonal timescales. These waves have the potential to provide an important source of predictability for high impact weather in Southeast (SE) Asia and the tropics more widely. To aid understanding of the role played in high impact weather by such waves, the observed statistical relationship between identified equatorial waves and heavy rainfall in SE Asia is examined for the period 1998-2016.
Increases in the amount of precipitation and the likelihood of extreme precipitation in SE Asia are linked to all three types of waves that are included in analysis; Kelvin, equatorial Rossby and WMRG waves. There is both increased mean rainfall and increased probability of occurrence of heavy rainfall on days when high amplitude waves propagate over SE Asia. In particular, heavy precipitation can be up to three times more likely in regions of SE Asia during equatorial waves, including Malaysia, Indonesia and the Philippines. Kelvin waves have a large influence on heavy rainfall over Indonesia, WMRG and Kelvin waves impact Malaysia rainfall, and equatorial Rossby and WMRG waves are linked to increased rainfall over the Philippines. Based on this study it can be concluded that the probability of extreme precipitation in this region is dependent on equatorial wave activity. Therefore, the skill in probabilistic prediction of extreme precipitation in SE Asia would be expected to be conditional on the skill in equatorial wave prediction, and the modelled relationship between equatorial waves and convection
OSSOS III - Resonant Trans-Neptunian Populations: Constraints from the first quarter of the Outer Solar System Origins Survey
The first two observational sky "blocks" of the Outer Solar System Origins
Survey (OSSOS) have significantly increased the number of well-characterized
observed trans-Neptunian objects (TNOs) in Neptune's mean motion resonances. We
describe the 31 securely resonant TNOs detected by OSSOS so far, and we use
them to independently verify the resonant population models from the
Canada-France Ecliptic Plane Survey (CFEPS; Gladman et al. 2012), with which we
find broad agreement. We confirm that the 5:2 resonance is more populated than
models of the outer Solar System's dynamical history predict; our minimum
population estimate shows that the high eccentricity (e>0.35) portion of the
resonance is at least as populous as the 2:1 and possibly as populated as the
3:2 resonance. One OSSOS block was well-suited to detecting objects trapped at
low libration amplitudes in Neptune's 3:2 resonance, a population of interest
in testing the origins of resonant TNOs. We detected three 3:2 objects with
libration amplitudes below the cutoff modeled by CFEPS; OSSOS thus offers new
constraints on this distribution. The OSSOS detections confirm that the 2:1
resonance has a dynamically colder inclination distribution than either the 3:2
or 5:2 resonances. Using the combined OSSOS and CFEPS 2:1 detections, we
constrain the fraction of 2:1 objects in the symmetric mode of libration to be
0.2-0.85; we also constrain the fraction of leading vs. trailing asymmetric
librators, which has been theoretically predicted to vary depending on
Neptune's migration history, to be 0.05-0.8. Future OSSOS blocks will improve
these constraints.Comment: Accepted for publication in A
Antimicrobial resistance control activities at a tertiary hospital in a low-resource setting: an example of Queen Elizabeth Central Hospital in Malawi
BackgroundAddressing AMR has been most problematic in low- and middle-income countries, which lack infrastructure, diagnostic capacity, and robust data management systems, among other factors. The implementation of locally-led efforts in a low-income country to develop sustainability and build capacity for AMR control within the existing infrastructure has not been well documented.MethodsWe detail current AMR control initiatives at Queen Elizabeth Central Hospital, a tertiary referral government hospital in Malawi with limited resources, and present the activities accomplished to date, lessons learned, and challenges ahead.ResultsThe key areas of AMR control initiatives that the group focused on included laboratory diagnostics and surveillance, antimicrobial stewardship, infection prevention and control, pharmacy, leadership, education, and funding.DiscussionThe hospital AMR Control Working Group increased awareness, built capacity, and implemented activities around AMR control throughout the hospital, in spite of the resource limitations in this setting. Our results are based on the substantial leadership provided by the working group and committed stakeholders who have taken ownership of this process.ConclusionLimited resources pose a challenge to the implementation of AMR control activities in low- and middle-income countries. Leadership is central to implementation. Future efforts will need to transition the initiative from an almost fully personal commitment to one with wider engagement to ensure sustainability
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