169 research outputs found
A Multi-Case Examination of Training of Self-Explanation when Combined with Worked Examples
As more students enter higher education unprepared for college level mathematics, amelioration of deficiencies may be a key barrier which, once faced, will increase overall college graduation rates (Attewell, Lavin, Domina, & Levey, 2006). Corequisite courses offer the opportunity for the underprepared learner to take the gateway mathematics course with support (Complete College America, 2012). Upon passing, mathematics and STEM courses will “unlock,” thus allowing the learner to successfully complete their degree requirements. Faculty are challenged to retain the rigor of college-level coursework while supporting learners who possess a wide range of mathematics levels (Daugherty, Gomez, Carew, Mendoza-Graf, & Miller, 2018). Implementing a corequisite curriculum requires the creation or adaptation of materials and instructional strategies to align the basic skills instruction into the college-level content. A case study was conducted with the sample population of college undergraduates (N = 43) enrolled in two sections of College Algebra and participated within a 14-week semester course. A generative learning strategy, self-explanation when combined with worked examples, was introduced during Week 5, when multi-step problems were encountered. Training within the intervention was given to one section. The other section was informed that the strategy was useful to understanding mathematics. The quality of the self-explanation produced was evaluated at the beginning and end of the intervention. Attitudinal data was captured in a pre-and post-Mathematical Attitudes and Perception Surveys (MAPS), in addition to participant semi-structured interviews and a reflection.
The sections were compared on measures of quality of the artifact produced, MAPS survey data, and through categories of ability as determined by incoming ACT score. The result indicated that those trained in self-explanation when combined with worked examples produced artifacts of higher quality. The participants who had the lowest incoming mathematical scores (ACT mathematics sub score \u3c 17) produced higher quality self-explanations than any other mathematical score category from either case.
Attitudinal data showed that the trained section had marked increases in mathematical attitudes, with the highest increase in confidence. The untrained section’s attitudes stayed relatively consistent throughout the study. Interviews and reflections indicated that, for both sections, the intervention assisted in mathematical understanding and metacognition. Trained participants used both components to understand and identify mathematical knowledge gaps. The majority of the untrained participants devoted more attention to the worked example portion of the intervention to create mathematical meaning and identify misunderstandings.
This study found that training the learner was an important aspect of the intervention and was necessary to produce results of a higher quality along with positive mathematical attitudes
Variation in the performance of speech acts in Peninsular Spanish: apologies and requests
This study examines variations in the performance of speech acts and additional discourse features in situational speech patterns of Peninsular Spanish. Based on studies by Blum-Kulka, et al. (1989), nine situations were created, varying from less severe to more severe, to elicit natural responses for apologies and requests. Forty participants from Castile and Andalusia were interviewed, and the data were coded to examine the differences in speech act realizations and the use of specific discourse features. The participants’ responses were classified by regional, gender, and age differences for the data set. Sociolinguistic differences in the use of additional discourse features were also compared, examining the use of alerters, personal address items, intensifiers, polite markers, hedges, accepting responsibility, offering repair, and the expression of need. In part three of this study, native speaker judgments and metalinguistic discussions were conducted to test the speech act data of participants from Castile and Andalusia and to verify the acceptability of the responses. Results show that in the performance of speech acts, little variation is seen for region, gender, and age. The speech acts for apologies and requests are formulaic in nature, and only change with situational variation. Likewise, even though some differences exist, there is no statistical significance in the use of additional discourse features according to region, gender, and age. The use of these discourse features provides information for Spanish language variation and in the areas of linguistic politeness and language and gender. Results from the metalinguistic discussions provide qualitative data, supporting the findings of speech act realizations. Further investigation is suggested modifying targeted speech acts and situational contexts
Design Effects of Multilevel Estimates From National Probability Samples
Abstract This research empirically evaluates data sets from the National Center for Education Statistics (NCES) for design effects of ignoring the sampling design in weighted two-level analyses. Currently, researchers may ignore the sampling design beyond the levels that they model which might result in incorrect inferences regarding hypotheses due to biased standard error estimates; the degree of bias depends on the informativeness of any ignored stratification and clustering in the sampling design. Some multilevel software packages accommodate first-stage sampling design information for two-level models but not all. For five example public release data sets from the NCES, design effects of ignoring the sampling design in unconditional and conditional two-level models are presented for 15 dependent variables selected based on a review of published research using these five data sets. Empirical findings suggest that there are minor effects of ignoring the additional sampling design and no differences in inference would be made had the first-stage sampling design been ignored. Strategically, researchers without access to multilevel software that can accommodate the sampling might consider including stratification variables as independent variables at level 2 of their model
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Prevalence and characteristics of student attitude surveys used in public elementary schools in the United States
There is anecdotal evidence of an increase in school administrator\u27s use of surveys of students to obtain school climate information even though it is difficult to obtain valid measurement from student self-report. To better understand the context, this research estimated the prevalence of the use of student surveys in elementary schools and reviewed the types of questions and response options currently used in applied settings. A survey was administered to a nationally representative sample of 300 public elementary school principals (34% response rate). Approximately half of the schools use surveys of students in their schools, with rates of surveying depending on the grade. A qualitative review of example surveys suggests that many typically-used questions may be problematic, given research on best methods of attitude measurement. Suggestions for practice and future research directions are provided. Accessed 11,640 times on https://pareonline.net from May 18, 2010 to December 31, 2019. For downloads from January 1, 2020 forward, please click on the PlumX Metrics link to the right
Development of coronary dysfunction in adult progeny after maternal engineered nanomaterial inhalation during gestation
Maternal exposure to environmental contaminants during pregnancy can profoundly influence the risk of developing cardiovascular disease in adult offspring. Our previous studies have demonstrated impaired cardiovascular health, microvascular reactivity, and cardiac function in fetal and young adult progeny after maternal inhalation of nano-sized titanium dioxide (nano-TiO2) aerosols during gestation. The present study was designed to evaluate the development of cardiovascular and metabolic diseases later in adulthood. Pregnant Sprague-Dawley rats were exposed to nano-TiO2 aerosols (similar to 10 mg/m(3), 134 nm median diameter) for 4 h per day, 5 days per week, beginning on gestational day (GD) 4 and ending on GD 19. Progeny were delivered in-house. Body weight was recorded weekly after birth. After 47 weeks, the body weight of exposed progeny was 9.4% greater compared with controls. Heart weight, mean arterial pressure, and plasma biomarkers of inflammation, dyslipidemia, and glycemic control were recorded at 3, 9 and 12 months of age, with no significant adaptations. While no clinical risk factors (i.e., hypertension, dyslipidemia, or systemic inflammation) emerged pertaining to the development of cardiovascular disease, we identified impaired endothelium-dependent and -independent arteriolar dysfunction and cardiac morphological alterations consistent with myocardial inflammation, degeneration, and necrosis in exposed progeny at 12 months. In conclusion, maternal inhalation of nano-TiO2 aerosols during gestation may promote the development of coronary disease in adult offspring
Structure-Function Relationships of the Mycobacterium tuberculosis Transcription Factor WhiB1
Background
Members of the WhiB-like (Wbl) protein family possess iron-sulfur clusters and are implicated in the regulation of developmental processes in Actinomycetes. Mycobacterium tuberculosis possesses seven Wbl proteins. The [4Fe-4S] cluster of M. tuberculosis WhiB1 is relatively insensitive to O2 but very sensitive to nitric oxide (NO). Nitric oxide nitrosylates the WhiB1 iron-sulfur cluster and promotes DNA-binding; the apo-forms of WhiB1 also bind DNA. However, the molecular requirements for iron-sulfur cluster acquisition and for DNA-binding by WhiB1 are poorly characterized.
Methods and Findings
WhiB1 variants were created by site-directed mutagenesis and the abilities of the corresponding proteins to acquire an iron-sulfur cluster and/or bind to whiB1 promoter DNA were assessed. All four Cys residues (Cys9, 37, 40, and 46) in the N-terminal region of WhiB1 were required for incorporation of a [4Fe-4S] cluster, whereas a possible alternative cluster ligand Asp13 (by analogy with M. smegmatis WhiB2) was not. The C-terminal region of WhiB1 is predicted to house the DNA-binding domain of the protein consisting of a predicted β-turn (58GVWGG62) followed by two amino acid motifs (72KRRN75 and 78TKAR81) that are conserved in WhiB1 proteins. Gly residues (Gly58, 61 and 62) in the β-turn and positively-charged residues (Lys72, Arg73, Arg74, Lys79 and Arg81) in the downstream conserved regions were required for binding of WhiB1 DNA.
Conclusions
Site-directed mutagenesis of M. tuberculosis whiB1 and characterization of the corresponding proteins has been used to explore structure-function relationships of the NO-responsive transcription factor WhiB1. This showed that all four conserved Cys residues in the N-terminal region are required for incorporation of iron-sulfur clusters but not for DNA-binding. Analysis of variants with amino acid substitutions in the C-terminal region revealed the crucial roles played by a predicted β-turn and two conserved positively-charged motifs in facilitating DNA-binding, but not iron-sulfur cluster acquisition, by WhiB1
Use of magnetic source imaging to assess recovery after severe traumatic brain injury—an MEG pilot study
RationaleSevere TBI (sTBI) is a devastating neurological injury that comprises a significant global trauma burden. Early comprehensive neurocritical care and rehabilitation improve outcomes for such patients, although better diagnostic and prognostic tools are necessary to guide personalized treatment plans.MethodsIn this study, we explored the feasibility of conducting resting state magnetoencephalography (MEG) in a case series of sTBI patients acutely after injury (~7 days), and then about 1.5 and 8 months after injury. Synthetic aperture magnetometry (SAM) was utilized to localize source power in the canonical frequency bands of delta, theta, alpha, beta, and gamma, as well as DC–80 Hz.ResultsAt the first scan, SAM source maps revealed zones of hypofunction, islands of preserved activity, and hemispheric asymmetry across bandwidths, with markedly reduced power on the side of injury for each patient. GCS scores improved at scan 2 and by scan 3 the patients were ambulatory. The SAM maps for scans 2 and 3 varied, with most patients showing increasing power over time, especially in gamma, but a continued reduction in power in damaged areas and hemispheric asymmetry and/or relative diminishment in power at the site of injury. At the group level for scan 1, there was a large excess of neural generators operating within the delta band relative to control participants, while the number of neural generators for beta and gamma were significantly reduced. At scan 2 there was increased beta power relative to controls. At scan 3 there was increased group-wise delta power in comparison to controls.ConclusionIn summary, this pilot study shows that MEG can be safely used to monitor and track the recovery of brain function in patients with severe TBI as well as to identify patient-specific regions of decreased or altered brain function. Such MEG maps of brain function may be used in the future to tailor patient-specific rehabilitation plans to target regions of altered spectral power with neurostimulation and other treatments
Phase I pharmacokinetic and pharmacodynarnic study of 17-allylamino, 17-demethoxygeldanamycin in patients with advanced malignancies
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