1,804 research outputs found
Kuhlmeier v. Hazelwood School District: The First amendment rights of Public High School Students
In Kuhlmeier v. Hazelwood School District, the Supreme Court held that high school students\u27 first amendment rights were not violated when their principal deleted articles from the school newspaper. The Court stated that the school newspaper was not a public forum for expression which normally receives full first amendment protection. The Court further held that the school principal did not violate students\u27 first amendment rights when he restricted the printing of articles due to the effect that they could have on other students.
The Supreme Court\u27s decision will undoubtedly curtail students\u27 rights to free speech and press. This casenote will first present a brief history of the first amendment as it applies to public schools. An analysis of the Kuhlmeier decision will follow, demonstrating why the Kuhlmeier holding represents a major step backwards for both first amendment freedom and the American educational process
Pre-training with Scientific Text Improves Educational Question Generation
With the boom of digital educational materials and scalable e-learning systems, the potential for realising AI-assisted personalised learning has skyrocketed. In this landscape, the automatic generation of educational questions will play a key role, enabling scalable self-assessment when a global population is manoeuvring their personalised learning journeys. We develop EduQG, a novel educational question generation model built by adapting a large language model. Our initial experiments demonstrate that EduQG can produce superior educational questions by pre-training on scientific text
Development and Psychometric Evaluation of the Assessment of Core CBT Skills (ACCS): An Observation Based Tool for Assessing Cognitive Behavioural Therapy Competence
This paper outlines the development and psychometric evaluation of the Assessment of Core CBT Skills (ACCS) rating scale. The ACCS aims to provide a novel assessment framework to deliver formative and summative feedback regarding therapistsâ performance within observed cognitive-behavioural treatment sessions, and for therapists to rate and reflect on their own performance. Findings from three studies are outlined: 1) a feedback study (N = 66) examining content validity, face validity and usability, 2) a focus group (N = 9) evaluating usability and utility, and 3) an evaluation of the psychometric properties of the ACCS in âreal worldâ CBT training and routine clinical practice contexts. Results suggest that the ACCS has good face validity, content validity, and usability and provides a user-friendly tool that is useful for promoting self-reflection and providing formative feedback. Scores on both the self and assessor-rated versions of the ACCS demonstrate good internal consistency, inter-rater reliability, and discriminant validity. In addition, ACCS scores were found to be correlated with, but distinct from the Revised Cognitive Therapy Scale (CTS-R) and were comparable to CTS-R scores in terms of internal consistency and discriminant validity. Additionally, the ACCS may have advantages over the CTS-R in terms of inter-rater reliability of scores. The studies also provided insight into areas for refinement and a number of modifications were undertaken to improve the scale. In summary, the ACCS is an appropriate and useful measure of CBT competence that can be used to promote self-reflection and provide therapists with formative and summative feedback
A Meiotic Checkpoint Alters Repair Partner Bias to Permit Inter-sister Repair of Persistent DSBs
Accurate meiotic chromosome segregation critically depends on the formation of inter-homolog crossovers initiated by double-strand breaks (DSBs). Inaccuracies in this process can drive aneuploidy and developmental defects, but how meiotic cells are protected from unscheduled DNA breaks remains unexplored. Here we define a checkpoint response to persistent meiotic DSBs in C. elegans that phosphorylates the synaptonemal complex (SC) to switch repair partner from the homolog to the sister chromatid. A key target of this response is the core SC component SYP-1, which is phosphorylated in response to ionizing radiation (IR) or unrepaired meiotic DSBs. Failure to phosphorylate (syp-16A) or dephosphorylate (syp-16D) SYP-1 in response to DNA damage results in chromosome non-dysjunction, hyper-sensitivity to IR-induced DSBs, and synthetic lethality with loss of brc-1BRCA1. Since BRC-1 is required for inter-sister repair, these observations reveal that checkpoint-dependent SYP-1 phosphorylation safeguards the germline against persistent meiotic DSBs by channelling repair to the sister chromatid.Cancer Research UK FC0010048UK Medical Research Council FC0010048Wellcome Trust FC0010048Ministerio de EconomĂa y Competitividad BFU2016-75058-PEuropean Research Council ERC2014 AdG669898 TARLOO
Taking Stock of Reality: Biased Perceptions of the Costs of Romantic Partnersâ Sacrifices
When romantic partners sacrifice their own self-interest to benefit the relationship, the sacrificer or recipient mayâfor various reasonsâbe biased in how they perceive the costs that the sacrificer incurs. In Study 1, romantic couples (N = 125) rated their own and their partnerâs costs after a conversation about a sacrifice in the laboratory, followed by extensive experience sampling in their natural environment. In Study 2, a preregistered experiment, individuals (N = 775) imagined a scenario in which they, their partner, or an unknown person sacrificed and rated the associated costs and benefits. Both studies demonstrated a consistent discrepancy between perceptions of own and partner sacrifice, driven primarily by people underestimating their own sacrifice costs and overestimating the benefits (Study 2). Results across studies showed that this underestimation bias helps people to feel better and feel more satisfied in the relationship when giving up their own goals and preferences for the relationship
RNA polymerase is poised for activation across the genome
Regulation of gene expression is integral to the development and survival of all organisms. Transcription begins with the assembly of a pre-initiation complex at the gene promoter, followed by initiation of RNA synthesis and the transition to productive elongation. In many cases, recruitment of RNA polymerase II (Pol II) to a promoter is necessary and sufficient for activation of genes. However, there are a few notable exceptions to this paradigm, including heat shock genes and several proto-oncogenes, whose expression is attenuated by regulated stalling of polymerase elongation within the promoter-proximal region. To determine the importance of polymerase stalling for transcription regulation, we carried out a genome-wide search for Drosophila melanogaster genes with Pol II stalled within the promoter-proximal region. Our data show that stalling is widespread, occurring at hundreds of genes that respond to stimuli and developmental signals. This finding indicates a role for regulation of polymerase elongation in the transcriptional responses to dynamic environmental and developmental cues
Cell-specific discrimination of desmosterol and desmosterol mimetics confers selective regulation of LXR and SREBP in macrophages.
Activation of liver X receptors (LXRs) with synthetic agonists promotes reverse cholesterol transport and protects against atherosclerosis in mouse models. Most synthetic LXR agonists also cause marked hypertriglyceridemia by inducing the expression of sterol regulatory element-binding protein (SREBP)1c and downstream genes that drive fatty acid biosynthesis. Recent studies demonstrated that desmosterol, an intermediate in the cholesterol biosynthetic pathway that suppresses SREBP processing by binding to SCAP, also binds and activates LXRs and is the most abundant LXR ligand in macrophage foam cells. Here we explore the potential of increasing endogenous desmosterol production or mimicking its activity as a means of inducing LXR activity while simultaneously suppressing SREBP1c-induced hypertriglyceridemia. Unexpectedly, while desmosterol strongly activated LXR target genes and suppressed SREBP pathways in mouse and human macrophages, it had almost no activity in mouse or human hepatocytes in vitro. We further demonstrate that sterol-based selective modulators of LXRs have biochemical and transcriptional properties predicted of desmosterol mimetics and selectively regulate LXR function in macrophages in vitro and in vivo. These studies thereby reveal cell-specific discrimination of endogenous and synthetic regulators of LXRs and SREBPs, providing a molecular basis for dissociation of LXR functions in macrophages from those in the liver that lead to hypertriglyceridemia
Correcting the Bias of Empirical Frequency Parameter Estimators in Codon Models
Markov models of codon substitution are powerful inferential tools for studying biological processes such as natural selection and preferences in amino acid substitution. The equilibrium character distributions of these models are almost always estimated using nucleotide frequencies observed in a sequence alignment, primarily as a matter of historical convention. In this note, we demonstrate that a popular class of such estimators are biased, and that this bias has an adverse effect on goodness of fit and estimates of substitution rates. We propose a âcorrectedâ empirical estimator that begins with observed nucleotide counts, but accounts for the nucleotide composition of stop codons. We show via simulation that the corrected estimates outperform the de facto standard estimates not just by providing better estimates of the frequencies themselves, but also by leading to improved estimation of other parameters in the evolutionary models. On a curated collection of sequence alignments, our estimators show a significant improvement in goodness of fit compared to the approach. Maximum likelihood estimation of the frequency parameters appears to be warranted in many cases, albeit at a greater computational cost. Our results demonstrate that there is little justification, either statistical or computational, for continued use of the -style estimators
Selective Constraints on Amino Acids Estimated by a Mechanistic Codon Substitution Model with Multiple Nucleotide Changes
Empirical substitution matrices represent the average tendencies of
substitutions over various protein families by sacrificing gene-level
resolution. We develop a codon-based model, in which mutational tendencies of
codon, a genetic code, and the strength of selective constraints against amino
acid replacements can be tailored to a given gene. First, selective constraints
averaged over proteins are estimated by maximizing the likelihood of each 1-PAM
matrix of empirical amino acid (JTT, WAG, and LG) and codon (KHG) substitution
matrices. Then, selective constraints specific to given proteins are
approximated as a linear function of those estimated from the empirical
substitution matrices.
Akaike information criterion (AIC) values indicate that a model allowing
multiple nucleotide changes fits the empirical substitution matrices
significantly better. Also, the ML estimates of transition-transversion bias
obtained from these empirical matrices are not so large as previously
estimated. The selective constraints are characteristic of proteins rather than
species. However, their relative strengths among amino acid pairs can be
approximated not to depend very much on protein families but amino acid pairs,
because the present model, in which selective constraints are approximated to
be a linear function of those estimated from the JTT/WAG/LG/KHG matrices, can
provide a good fit to other empirical substitution matrices including cpREV for
chloroplast proteins and mtREV for vertebrate mitochondrial proteins.
The present codon-based model with the ML estimates of selective constraints
and with adjustable mutation rates of nucleotide would be useful as a simple
substitution model in ML and Bayesian inferences of molecular phylogenetic
trees, and enables us to obtain biologically meaningful information at both
nucleotide and amino acid levels from codon and protein sequences.Comment: Table 9 in this article includes corrections for errata in the Table
9 published in 10.1371/journal.pone.0017244. Supporting information is
attached at the end of the article, and a computer-readable dataset of the ML
estimates of selective constraints is available from
10.1371/journal.pone.001724
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