308 research outputs found
Entanglement entropies in the ground states of helium-like atoms
We examine the entanglement in the ground states of helium and helium-like
ions using an original Hylleraas expansion. The von Neumann and linear
entropies of the reduced density matrix are accurately computed by performing
the Schmidt decomposition of the S singlet spatial wavefunctions. The results
presented are more accurate than currently available in published literature.Comment: 6 pages, 1 figur
Entanglement in helium atom confined in an impenetrable cavity
We explore ground-state entanglement properties of helium atom confined at
the center of an impenetrable spherical cavity of varying radius by using
explicitly correlated Hylleraas-type basis set. Results for the dependencies of
the von Neumann and linear entanglement entropic measures on the cavity radius
are discussed in details. Some highly accurate numerical results for the von
Neumann and linear entropy are reported for the first time. It is found that
the transition to the strong confinement regime is manifested by the entropies
as an appearance of the inflection points on their variations.Comment: 4 pages, 1 figure, Accepted by EPJ
Quantum entanglement of two harmonically trapped dipolar particles
We study systems of two identical dipolar particles confined in quasi
one-dimensional harmonic traps. Numerical results for the dependencies of the
entanglement on the control parameters of the systems are provided and
discussed in detail. In the limit of a strong interaction between the
particles, the occupancies and the von Neumann entropies of the bosonic and
fermionic ground states are derived in closed analytic forms by applying the
harmonic approximation. The strong correlation regimes of the system with the
dipolar bosons and the system with the charged ones are compared with each
other in regard to aspects of their entanglement.Comment: 5 pages,2 figure
The Impact of a Reading Workshop Approach in a Seventh Grade Supplemental Reading Class
This paper describes a problem of practice that developed due to a downward trend in reading achievement scores in an independent middle school in the Southeast. To address this problem, the researcher conducted an action research, mixed methods study to examine the impact of a reading workshop approach in a seventh-grade supplemental reading class. The mixed methods study was guided by one research question designed to collect quantitative data: What is the impact of a reading workshop approach on seventh-grade studentsā reading achievement as measured by the STAR reading assessment? It was also guided by two qualitative research questions that sought to measure both studentsā perceptions and teachersā perceptions regarding the effectiveness of a reading workshop model in a seventh-grade classroom. The results of the study indicated an increase in student achievement when the program was implemented with fidelity. Both student and teacher perceptions validated these results. An action plan and implications for immediate classroom practice as well as future research are included based on this studyās findings
Predicting Early Mild Cognitive Impairment With Free Recall: The Primacy of Primacy.
OBJECTIVES: Serial position effects have been found to discriminate between normal and pathological aging, and to predict conversion from Mild Cognitive Impairment (MCI) to Alzheimer's disease (AD). Different scoring methods have been used to estimate the accuracy of these predictions. In the current study, we investigated delayed primacy as predictor of progression to early MCI over established diagnostic memory methods. We also compared three serial position methods (regional, standard and delayed scores) to determine which measure is the most sensitive in differentiating between individuals who develop early MCI from a baseline of cognitively intact older adults. METHOD: Data were analyzed with binary logistic regression and with receiver-operating characteristic (ROC). Baseline serial position scores were collected using the Rey's Auditory Verbal Learning Test and used to predict conversion to early MCI. The diagnosis of early MCI was obtained through statistical algorithm and consequent consensus conference. One hundred and ninety-one participants were included in the analyses. All participants were aged 60 or above and cognitively intact at baseline. RESULTS: The binary logistic regression showed that delayed primacy was the only predictor of conversion to early MCI, when compared to total and delayed recall. ROC curves showed that delayed primacy was still the most sensitive predictor of progression to early MCI when compared to other serial position measures. CONCLUSIONS: These findings are consistent with previous studies and support the hypothesis that delayed primacy may be a useful cognitive marker of early detection of neurodegeneration
Temporal contiguity and ageing: The role of memory organization in cognitive decline
The temporal contiguity effect is the tendency to form associations between items presented in nearby study positions. In the present study, we explored whether temporal contiguity predicted conversion to cognitively unimpairedādeclining (CUD) status from a baseline of unimpaired older adults. Data from 419 participants were drawn from the Wisconsin Registry of Alzheimerās Prevention (WRAP) data set and analysed with binary logistic regressions. Temporal contiguity was calculated using the Rey Auditory Verbal Learning Test. Other predictors included age, years of education, sex, APOEāĪµ4 status, and other measures of memory recall. Lower temporal contiguity predicted conversion to CUD after accounting for covariates. These findings support the hypothesis that temporal organization in memory is related to cognitive decline and suggest that temporal contiguity may be used for studies of early detection
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