159 research outputs found
Assessing Teacher Attentiveness to Student Mathematical Thinking
This article illustrates an argument-based approach to presenting validity evidence for assessment items intended to measure a complex construct. Our focus is developing a measure of teachersâ ability to analyze and respond to studentsâ mathematical thinking for the purpose of program evaluation. Our validity argument consists of claims addressing connections between our item-development process and the theoretical model for the construct we are trying to measure: attentiveness. Evidence derived from theoretical arguments in conjunction with our multiphased item-development process is used to support the claims, including psychometric evidence of Rasch model fit and category ordering. Taken collectively, the evidence provides support for the claim that our selected-response items can measure increasing levels of attentiveness. More globally, our goal in presenting this work is to demonstrate how theoretical arguments and empirical evidence fit within an argument to support claims about how well a construct is represented, operationalized, and structured
Statewide Mathematics Professional Development: Teacher Knowledge, Self-Efficacy, and Beliefs
We examined the impact of a state mandated K-12 mathematics professional development course on knowledge, self-efficacy and beliefs of nearly 4,000 teachers and administrators. Participants completed the Mathematical Thinking for Instruction course, emphasizing student thinking, problem-solving, and content knowledge specific to mathematics instruction. Inventories utilizing items fromthe Learning Mathematics for Teaching project (2005) measured changes in participantsâ Mathematical Knowledge for Teaching (MKT) and an end-of-course self-evaluation enabled analysis of changes in MKT, self-efficacy and beliefs. Statistically significant changes were found in all three variables. This study adds to our understanding of the potential usefulness of mandating professional development as a policy vehicle for influencing educatorsâ mathematics knowledge and beliefs
Influence of Proportional Number Relationships on Item Accessibility and Studentsâ Strategies
Extensive evidence points to the need for mathematics instruction to tap into studentsâ informal understandings in order to conceptually develop formal mathematical ideas (Ahl, Moore, & Dixon, 1992; Freudenthal, 1973, 1991; Treffers, 1987). Contextual problems are a common means of helping students access their informal mathematical ideas (Lamon, 1993; Moore & Carlson, 2012). However, to successfully use context in this manner, we must ensure these problems are accessible to students and have the potential to promote connections to deeper or more formal mathematics (Jackson, Garrison, Wilson, Gibbons, & Shahan, 2013; Stein, Smith, Henningsen, & Silver, 2000). There is thus a need for research to identify what characteristics make contextual tasks accessible to students as a point of entry and useful for educators in analyzing and pressing studentsâ thinking
Can Teachers Accurately Predict Student Performance?
In two studies, we examined the effect of professional development to improve mathematics instruction on the accuracy of teachers\u27 monitoring of student learning. Study 1 was conducted with 36 teachers participating in three years of professional development. Judgment accuracy was influenced by the fidelity with which what was learned in the professional development. Study 2 was conducted with 64 teachers from 8 schools, which were randomly assigned to receive professional development or serve as a control. Judgment accuracy was greater for teachers receiving professional development than for teachers who did not and teachers were better to predict students\u27 computational skills
Early Elevation of Matrix Metalloproteinase-8 and -9 in Pediatric ARDS Is Associated with an Increased Risk of Prolonged Mechanical Ventilation
BACKGROUND: Matrix metalloproteinases (MMP) -8 and -9 may play key roles in the modulation of neutrophilic lung inflammation seen in pediatric Acute Respiratory Distress Syndrome (ARDS). We aimed to perform a comprehensive analysis of MMP-8 and MMP-9 activity in tracheal aspirates of pediatric ARDS patients compared with non-ARDS controls, testing whether increased MMP-8 and -9 activities were associated with clinical outcomes. METHODS: Tracheal aspirates were collected from 33 pediatric ARDS patients and 21 non-ARDS controls at 48 hours of intubation, and serially for those who remained intubated greater than five days. MMPs, tissue inhibitor of metalloproteinases (TIMPs), human neutrophil elastase (HNE) and myeloperoxidase (MPO) activity were measured by ELISA, and correlated with clinical indicators of disease severity such as PRISM (Pediatric Risk of Mortality) scores, oxygen index (OI), multi-organ system failure (MOSF) and clinical outcome measures including length of intubation, ventilator-free days (VFDs) and mortality in the Pediatric Intensive Care Unit (PICU). RESULTS: Active MMP-9 was elevated early in pediatric ARDS subjects compared to non-ARDS controls. Higher MMP-8 and active MMP-9 levels at 48 hours correlated with a longer course of mechanical ventilation (râ=â0.41, pâ=â0.018 and râ=â0.75, p<0.001; respectively) and fewer number of VFDs (râ=â-0.43, pâ=â0.013 and râ=â-0.76, p<0.001; respectively), independent of age, gender and severity of illness. Patients with the highest number of ventilator days had the highest levels of active MMP-9. MMP-9 and to a lesser extent MMP-8 activities in tracheal aspirates from ARDS subjects were sensitive to blockade by small molecule inhibitors. CONCLUSIONS: Higher MMP-8 and active MMP-9 levels at 48 hours of disease onset are associated with a longer duration of mechanical ventilation and fewer ventilator-free days among pediatric patients with ARDS. Together, these results identify early biomarkers predictive of disease course and potential therapeutic targets for this life threatening disease
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Common genetic variants in the CLDN2 and PRSS1-PRSS2 loci alter risk for alcohol-related and sporadic pancreatitis
Pancreatitis is a complex, progressively destructive inflammatory disorder. Alcohol was long thought to be the primary causative agent, but genetic contributions have been of interest since the discovery that rare PRSS1, CFTR, and SPINK1 variants were associated with pancreatitis risk. We now report two significant genome-wide associations identified and replicated at PRSS1-PRSS2 (1Ă10-12) and x-linked CLDN2 (p < 1Ă10-21) through a two-stage genome-wide study (Stage 1, 676 cases and 4507 controls; Stage 2, 910 cases and 4170 controls). The PRSS1 variant affects susceptibility by altering expression of the primary trypsinogen gene. The CLDN2 risk allele is associated with atypical localization of claudin-2 in pancreatic acinar cells. The homozygous (or hemizygous male) CLDN2 genotype confers the greatest risk, and its alleles interact with alcohol consumption to amplify risk. These results could partially explain the high frequency of alcohol-related pancreatitis in men â male hemizygous frequency is 0.26, female homozygote is 0.07
A Joint Fermi-GBM and Swift-BAT Analysis of Gravitational-wave Candidates from the Third Gravitational-wave Observing Run
We present Fermi Gamma-ray Burst Monitor (Fermi-GBM) and Swift Burst Alert Telescope (Swift-BAT) searches for gamma-ray/X-ray counterparts to gravitational-wave (GW) candidate events identified during the third observing run of the Advanced LIGO and Advanced Virgo detectors. Using Fermi-GBM onboard triggers and subthreshold gamma-ray burst (GRB) candidates found in the Fermi-GBM ground analyses, the Targeted Search and the Untargeted Search, we investigate whether there are any coincident GRBs associated with the GWs. We also search the Swift-BAT rate data around the GW times to determine whether a GRB counterpart is present. No counterparts are found. Using both the Fermi-GBM Targeted Search and the Swift- BAT search, we calculate flux upper limits and present joint upper limits on the gamma-ray luminosity of each GW. Given these limits, we constrain theoretical models for the emission of gamma rays from binary black hole mergers
Search for continuous gravitational wave emission from the Milky Way center in O3 LIGO--Virgo data
We present a directed search for continuous gravitational wave (CW) signals
emitted by spinning neutron stars located in the inner parsecs of the Galactic
Center (GC). Compelling evidence for the presence of a numerous population of
neutron stars has been reported in the literature, turning this region into a
very interesting place to look for CWs. In this search, data from the full O3
LIGO--Virgo run in the detector frequency band have been
used. No significant detection was found and 95 confidence level upper
limits on the signal strain amplitude were computed, over the full search band,
with the deepest limit of about at .
These results are significantly more constraining than those reported in
previous searches. We use these limits to put constraints on the fiducial
neutron star ellipticity and r-mode amplitude. These limits can be also
translated into constraints in the black hole mass -- boson mass plane for a
hypothetical population of boson clouds around spinning black holes located in
the GC.Comment: 25 pages, 5 figure
All-sky search for continuous gravitational waves from isolated neutron stars using Advanced LIGO and Advanced Virgo O3 data
We present results of an all-sky search for continuous gravitational waves which can be produced by spinning neutron stars with an asymmetry around their rotation axis, using data from the third observing run of the Advanced LIGO and Advanced Virgo detectors. Four different analysis methods are used to search in a gravitational-wave frequency band from 10 to 2048 Hz and a first frequency derivative from to Hz/s. No statistically-significant periodic gravitational-wave signal is observed by any of the four searches. As a result, upper limits on the gravitational-wave strain amplitude are calculated. The best upper limits are obtained in the frequency range of 100 to 200 Hz and they are at 95\% confidence-level. The minimum upper limit of is achieved at a frequency 111.5 Hz. We also place constraints on the rates and abundances of nearby planetary- and asteroid-mass primordial black holes that could give rise to continuous gravitational-wave signals
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