1,541 research outputs found
Feasibility study of storage concepts for Scout and other NASA solid propellant launch vehicles
Feasibility study of long term storing of Scout and other solid propellant launch vehicles in assembled, flightworthy configuration and facility requirement
Writing while Black: African American Vernacular English (AAVE) and perceived writing performance
In the education system, there have historically been inequities that have severely disadvantaged Black students academically. One area in which these inequities surface is on writing assessments in the form of lower scores. I argue that because the U.S. education system is centered around Standard American English (SAE), it disadvantages those from different linguistic backgrounds, specifically Black students, as they are most likely to be speakers of African American Vernacular English (AAVE). Although there are theoretical justifications for this, past literature has not empirically tied inequities on writing assessments to Black studentsâ use of AAVE. The current study used Natural Language Processing (NLP) to quantify studentsâ use of grammatical features of AAVE (e.g., multiple negation, completive done) on the written component of the Indiana Statewide Testing for Educational Progress-Plus (N=21,420) to investigate how studentsâ use of AAVE impacted writing scores. The relationships between race, gender, economic disadvantage, AAVE use, and writing scores were examined using a path model analysis in Mplus Version 8.4. Based on the results of the path model, it was concluded that those who identified as males and those who were economically disadvantaged had higher frequencies of AAVE use and lower scores on writing in comparison to those who identified as females and those who were not economically disadvantaged. Contrary to the hypothesized negative effect, as AAVE increased writing score increased (b=.05, p \u3c.001), but this parameter was small in magnitude and therefore ignorable. It was concluded that Black students received lower writing scores than white students, but based on the findings of the study, the score differences could not be attributed to Black studentsâ higher use of AAVE. Explanations for these unanticipated findings are explored and include assessment directions that may have limited the use of AAVE, concerns about the procedure used to measure AAVE, and assumptions made by the statistical model employed. Future research should continue to investigate the linguistic discrimination Black students experience as it relates to their use of AAVE and other factors mediating the relationship between race and writing, due to the presence of written components on consequential tests (SAT, GRE)
Chromosomal mapping of murine c-fes and c-src genes
The murine homologs of two viral oncogenes associated with tyrosine-specific kinase activity have been assigned to different loci in the mouse genome. The segregation of restriction site polymorphisms, as detected by probes that are specific for endogenous c-fes and c-src sequences, was followed in the DNA of recombinant inbred strains. The c-fes gene was mapped to the proximal portion of chromosome 7, very close to the Gpi-1 locus, whereas c-src was linked to the Psp locus on the distal half of chromosome 2
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Neurophysiological and brain structural markers of cognitive frailty differs from Alzheimerâs disease
AbstractWith increasing life span, there is growing importance of understanding the mechanisms of successful cognitive ageing. In contrast, cognitive frailty has been proposed to be a precursor to Alzheimerâs disease. Here we test the hypothesis that cognitively frail adults represent a branch of healthy ageing, distinct from latent dementia. We used electro-magnetoencephalography and magnetic resonance imaging to investigate the structural and neurophysiological features of cognitive frailty in relation to healthy aging, and clinical presentations of mild cognitive impairment and Alzheimerâs disease. Cognitive performance of the cognitively frail group was similar to those with mild cognitive impairment. We used a novel cross-modal oddball task to induce mismatch responses to unexpected stimuli. Both controls and cognitively frail showed stronger mismatch responses and larger temporal grey matter volume, compared to people with mild cognitive impairment and Alzheimerâs disease. Our results suggest that cognitively frail represents a spectrum of normal ageing rather than incipient or undiagnosed Alzheimerâs disease. Lower cognitive reserve, hearing impairment and medical comorbidity might contribute to the aetiology of cognitive impairment.The study was supported by the Medical Research Council [SUAG/004 RG91365, SUAG/046
RG101400; SUAG/051 RG101400], the Wellcome Trust [103838], the Dementias Platform UK
[MR/L023784/1 & MR/L023784/2], Alzheimerâs Research UK [ARUK-PG2017B-19], a Holt
Fellowship, and NIHR Cambridge Biomedical Research Centre (BRC-1215-20014). The views
expressed are those of the authors and not necessarily those of the NIHR or the Department of
Health and Social Care. For the purpose of open access, the author has applied a CC BY public
copyright license to any Author Accepted Manuscript version arising from this submission
In-Situ and Experimental Evidence for Acidic Weathering of Rocks and Soils on Mars
Experimental data for alteration of synthetic Martian basalts at pH=0-1 indicate that chemical fractionations at low pH are vastly different from those observed during terrestrial weathering. Rock analyses from Gusev crater are well described by the relationships apparent from low pH experimental alteration data. A model for rock surface alteration is developed which indicates that a leached alteration zone is present on rock surfaces at Gusev. This zone is not chemically fractionated to a large degree from the underlying rock interior, indicating that the rock surface alteration process has occurred at low fluid-to-rock ratio. The geochemistry of natural rock surfaces analyzed by APXS is consistent with a mixture between adhering soil/dust and the leached alteration zone. The chemistry of rock surfaces analyzed after brushing with the RAT is largely representative of the leached alteration zone. The chemistry of rock surfaces analyzed after grinding with the RAT is largely representative of the interior of the rock, relatively unaffected by the alteration process occurring at the rock surface. Elemental measurements from the Spirit, Opportunity, Pathfinder and Viking 1 landing sites indicate that soil chemistry from widely separated locations is consistent with the low-pH, low fluid to rock ratio alteration relationships developed for Gusev rocks. Soils are affected principally by mobility of FeO and MgO, consistent with alteration of olivine-bearing basalt and subsequent precipitation of FeO and MgO bearing secondary minerals as the primary control on soil geochemistry
Religion and religious education : comparing and contrasting pupilsâ and teachersâ views in an English school
This publication builds on and develops the English findings of the qualitative study of European teenagersâ perspectives on religion and religious education (Knauth et al. 2008), part of âReligion in Education: A contribution to dialogue or a factor of conflict in transforming societies of European countries?â (REDCo) project. It uses data gathered from 27 pupils, aged 15-16, from a school in a multicultural Northern town in England and compares those findings with data gathered from ten teachers in the humanities faculty of the same school, collected during research for the Warwick REDCo Community of Practice. Comparisons are drawn between the teachersâ and their pupilsâ attitudes and values using the same structure as the European study: personal views and experiences of religion, the social dimension of religion, and religious education in school. The discussion offers an analysis of the similarities and differences in worldviews and beliefs which emerged. These include religious commitment/observance differences between the mainly Muslim-heritage pupils and their mainly non-practising Christian-heritage teachers. The research should inform the ways in which the statutory duties to promote community cohesion and equalities can be implemented in schools. It should also facilitate intercultural and interreligious understanding between teachers and the pupils from different ethnic and religious backgrounds
GABA-ergic Dynamics in Human Frontotemporal Networks Confirmed by Pharmaco-Magnetoencephalography.
To bridge the gap between preclinical cellular models of disease and in vivo imaging of human cognitive network dynamics, there is a pressing need for informative biophysical models. Here we assess dynamic causal models (DCM) of cortical network responses, as generative models of magnetoencephalographic observations during an auditory oddball roving paradigm in healthy adults. This paradigm induces robust perturbations that permeate frontotemporal networks, including an evoked 'mismatch negativity' response and transiently induced oscillations. Here, we probe GABAergic influences in the networks using double-blind placebo-controlled randomized-crossover administration of the GABA reuptake inhibitor, tiagabine (oral, 10 mg) in healthy older adults. We demonstrate the facility of conductance-based neural mass mean-field models, incorporating local synaptic connectivity, to investigate laminar-specific and GABAergic mechanisms of the auditory response. The neuronal model accurately recapitulated the observed magnetoencephalographic data. Using parametric empirical Bayes for optimal model inversion across both drug sessions, we identify the effect of tiagabine on GABAergic modulation of deep pyramidal and interneuronal cell populations. We found a transition of the main GABAergic drug effects from auditory cortex in standard trials to prefrontal cortex in deviant trials. The successful integration of pharmaco- magnetoencephalography with dynamic causal models of frontotemporal networks provides a potential platform on which to evaluate the effects of disease and pharmacological interventions.SIGNIFICANCE STATEMENT Understanding human brain function and developing new treatments require good models of brain function. We tested a detailed generative model of cortical microcircuits that accurately reproduced human magnetoencephalography, to quantify network dynamics and connectivity in frontotemporal cortex. This approach identified the effect of a test drug (GABA-reuptake inhibitor, tiagabine) on neuronal function (GABA-ergic dynamics), opening the way for psychopharmacological studies in health and disease with the mechanistic precision afforded by generative models of the brain
Scaling and Formulary cross sections for ion-atom impact ionization
The values of ion-atom ionization cross sections are frequently needed for
many applications that utilize the propagation of fast ions through matter.
When experimental data and theoretical calculations are not available,
approximate formulas are frequently used. This paper briefly summarizes the
most important theoretical results and approaches to cross section calculations
in order to place the discussion in historical perspective and offer a concise
introduction to the topic. Based on experimental data and theoretical
predictions, a new fit for ionization cross sections is proposed. The range of
validity and accuracy of several frequently used approximations (classical
trajectory, the Born approximation, and so forth) are discussed using, as
examples, the ionization cross sections of hydrogen and helium atoms by various
fully stripped ions.Comment: 46 pages, 8 figure
Finding a moral homeground: appropriately critical religious education and transmission of spiritual values
Values-inspired issues remain an important part of the British school curriculum. Avoiding moral relativism while fostering enthusiasm for spiritual values and applying them to non-curricular learning such as school ethos or children's home lives are challenges where spiritual, moral, social and cultural (SMSC) development might benefit from leadership by critical religious education (RE). Whether the school's model of spirituality is that of an individual spiritual tradition (schools of a particular religious character) or universal pluralistic religiosity (schools of plural religious character), the pedagogy of RE thought capable of leading SMSC development would be the dialogical approach with examples of successful implementation described by Gates, Ipgrave and Skeie. Marton's phenomenography, is thought to provide a valuable framework to allow the teacher to be appropriately critical in the transmission of spiritual values in schools of a particular religious character as evidenced by Hella's work in Lutheran schools
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