2,589 research outputs found
Representational differences in how students compare measurements
Measurement uncertainty plays a critical role in the process of experimental
physics. It is useful to be able to assess student proficiency around the topic
to iteratively improve instruction and student learning. For the topic of
measurement uncertainty, we developed an assessment tool called the Survey of
Physics Reasoning on Uncertainty Concepts in Experiments (SPRUCE), which aims
to assess students' knowledge, and use of, a variety of concepts related to
measurement uncertainty. This assessment includes two isomorphic questions
focused on comparing two measurements with uncertainty. One is presented
numerically and the other pictorially. Despite the questions probing identical
concepts, students answer them in different ways, indicating that they rely on
distinct modes of representation to make sense of measurement uncertainty and
comparisons. Specifically, students score much higher on the pictorially
represented item, which suggests possible instructional changes to leverage
students' use of representations while working with concepts of measurement
uncertainty.Comment: 4 pages, 2 figures, to be published in PERC Conference Proceedings
202
EuSrMnO: a three-dimensional XY spin glass
The frequency, temperature, and dc-bias dependence of the ac-susceptibility
of a high quality single crystal of the EuSrMnO layered
manganite is investigated. EuSrMnO behaves like a XY spin
glass with a strong basal anisotropy. Dynamical and static scalings reveal a
three-dimensional phase transition near = 18 K, and yield critical
exponent values between those of Heisenberg- and Ising-like systems, albeit
slightly closer to the Ising case. Interestingly, as in the latter system, the
here observed rejuvenation effects are rather weak. The origin and nature of
the low temperature XY spin glass state is discussed.Comment: REVTeX 4 style; 5 pages, 4 figure
Couplet scoring for research based assessment instruments
Contemporary content-focused research-based assessment instruments typically
use instrument items (i.e., questions) as the unit of assessment for instrument
scoring, reporting, and validation. However, traditional item-based scoring has
a number of limitations, including several arising from the use of the common
assessment development conventions of single-construct items,
unidimensionality, and single-correct-answer items. Couplet scoring, introduced
in this paper, employs the couplet as an alternative unit of assessment, where
a couplet is essentially an item viewed and scored through the lens of a
specific assessment objective (AO). With couplet scoring, a single item may
have more than one AO and therefore more than one couplet. In this paper, we
outline the limitations of traditional item scoring, introduce couplet scoring
and discuss its affordances (especially as they relate to limitations of item
scoring), and use a recently developed content RBAI to ground our discussion.Comment: 13 pages, 2 figure
Experimental phase equilibria constraints on pre-eruptive storage conditions of the Soufreiere Hills magma
Transcriptomic analysis of autistic brain reveals convergent molecular pathology.
Autism spectrum disorder (ASD) is a common, highly heritable neurodevelopmental condition characterized by marked genetic heterogeneity. Thus, a fundamental question is whether autism represents an aetiologically heterogeneous disorder in which the myriad genetic or environmental risk factors perturb common underlying molecular pathways in the brain. Here, we demonstrate consistent differences in transcriptome organization between autistic and normal brain by gene co-expression network analysis. Remarkably, regional patterns of gene expression that typically distinguish frontal and temporal cortex are significantly attenuated in the ASD brain, suggesting abnormalities in cortical patterning. We further identify discrete modules of co-expressed genes associated with autism: a neuronal module enriched for known autism susceptibility genes, including the neuronal specific splicing factor A2BP1 (also known as FOX1), and a module enriched for immune genes and glial markers. Using high-throughput RNA sequencing we demonstrate dysregulated splicing of A2BP1-dependent alternative exons in the ASD brain. Moreover, using a published autism genome-wide association study (GWAS) data set, we show that the neuronal module is enriched for genetically associated variants, providing independent support for the causal involvement of these genes in autism. In contrast, the immune-glial module showed no enrichment for autism GWAS signals, indicating a non-genetic aetiology for this process. Collectively, our results provide strong evidence for convergent molecular abnormalities in ASD, and implicate transcriptional and splicing dysregulation as underlying mechanisms of neuronal dysfunction in this disorder
Recommended from our members
Dementia assessment and management in primary care settings: a survey of current provider practices in the United States.
BACKGROUND:Primary care providers (PCPs) are typically the first to screen and evaluate patients for neurocognitive disorders (NCDs), including mild cognitive impairment and dementia. However, data on PCP attitudes and evaluation and management practices are sparse. Our objective was to quantify perspectives and behaviors of PCPs and neurologists with respect to NCD evaluation and management. METHODS:A cross-sectional survey with 150 PCPs and 50 neurologists in the United States who evaluated more than 10 patients over age 55 per month. The 51-item survey assessed clinical practice characteristics, and confidence, perceived barriers, and typical practices when diagnosing and managing patients with NCDs. RESULTS:PCPs and neurologists reported similar confidence and approaches to general medical care and laboratory testing. Though over half of PCPs performed cognitive screening or referred patients for cognitive testing in over 50% of their patients, only 20% reported high confidence in interpreting results of cognitive tests. PCPs were more likely to order CT scans than MRIs, and only 14% of PCPs reported high confidence interpreting brain imaging findings, compared to 70% of specialists. Only 21% of PCPs were highly confident that they correctly recognized when a patient had an NCD, and only 13% were highly confident in making a specific NCD diagnosis (compared to 72 and 44% for neurologists, both p < 0.001). A quarter of all providers identified lack of familiarity with diagnostic criteria for NCD syndromes as a barrier to clinical practice. CONCLUSIONS:This study demonstrates how PCPs approach diagnosis and management of patients with NCDs, and identified areas for improvement in regards to cognitive testing and neuroimaging. This study also identified all providers' lack of familiarity with published diagnostic criteria for NCD syndromes. These findings may inform the development of new policies and interventions to help providers improve the efficacy of their decision processes and deliver better quality care to patients with NCDs
Survey of physics reasoning on uncertainty concepts in experiments: an assessment of measurement uncertainty for introductory physics labs
Measurement uncertainty is a critical feature of experimental research in the
physical sciences, and the concepts and practices surrounding measurement
uncertainty are important components of physics lab courses. However, there has
not been a broadly applicable, research-based assessment tool that allows
physics instructors to easily measure students' knowledge of measurement
uncertainty concepts and practices. To address this need, we employed
Evidence-Centered Design to create the Survey of Physics Reasoning on
Uncertainty Concepts in Experiments (SPRUCE). SPRUCE is a pre-post assessment
instrument intended for use in introductory (first- and second-year) physics
lab courses to help instructors and researchers identify student strengths and
challenges with measurement uncertainty. In this paper, we discuss the
development of SPRUCE's assessment items guided by Evidence-Centered Design,
focusing on how instructors' and researchers' assessment priorities were
incorporated into the assessment items and how students' reasoning from pilot
testing informed decisions around item answer options.Comment: 23 pages, 11 figures, submitted as part of the Physical Review
Physics Education Research Focused Collection on Instructional Labs:
Improving Traditions and New Direction
Signatures of Spin Glass Freezing in NiO Nanoparticles
We present a detailed study of the magnetic properties of sol-gel prepared
nickel oxide nanoparticles of different sizes. We report various measurements
such as frequency, field and temperature dependence of ac susceptibility,
temperature and field dependence of dc magnetization and time decay of
thermoremanent magnetization. Our results and analysis show that the system
behaves as a spin glass.Comment: 8 pages, 9 figure
- …