Online or offline? Exploring working memory constraints in spatial updating

All spatial representation theories rely upon two spatial updating processes in order to maintain spatially consistent self-to-object relationships: movement-driven, automatic online updating and offline, conscious mental transformations of perspective. Theoretical differentiation based on offline updating is difficult given the equivalent predictions for many of the spatial tasks commonly used (i.e. egocentric pointing). However, representational theories do diverge with respect to the predicted working memory constraints of online updating. In experiment one participants studied groups of 4, 6, & 8 targets, engaged in a 180º rotation on half the trials and completed a series of judgments of relative direction and egocentric pointing. Set size effects for both tasks were limited to latencies alone, suggesting offline updating. Experiment two had participants study smaller (3 target) configurations and make egocentric pointing responses. On half the trials, participants engaged in either a verbal or spatial 1-back task during both retention and rotation periods. No effect of dual-task load or type were found for egocentric pointing. Both latencies and errors were significantly greater for the post-rotation pointing suggesting offline updating. The lack of evidence for online updating is surprising and contrary to previous findings that it is an obligatory automatic process (e.g. Farrell & Thomson, 1998). Multiple models were developed within ACT-R/S (Harrison & Schunn, 2003) illustrating the sufficiency of offline updating to account for the current findings. The challenges of detecting online updating and investigating its working memory constraints are discussed in the light of these results and simulations

A STUDY OF THE ENERGETICS OF THE CL2/MGO(001) INTERFACE USING CORRELATION CORRECTED PERIODIC HARTREE-FOCK THEORY

Published versio

Genetic risk scores demonstrate the cumulative association of single nucleotide polymorphisms in gut microbiome-related genes with obesity phenotypes in preschool age children

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/151317/1/ijpo12530_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/151317/2/ijpo12530.pd

Periodontitis: implementation tools for daily practice

This article offers a practical approach for practitioners when classifying periodontitis following the publication of the 2017 Classification of Periodontal and Peri-Implant Diseases and Conditions

Operationalising cognitive fatigability in multiple sclerosis: a Gordian knot that can be cut?

Background: Researchers have attempted to operationalise objective measures of cognitive fatigability in multiple sclerosis (MS) to overcome the perceived subjectivity of patient-reported outcomes of fatigue (PROs). Measures of cognitive fatigability examine decrements in performance during sustained neurocognitive tasks. Objective: This personal viewpoint briefly summarises available evidence for measures of cognitive fatigability in MS and considers their overall utility. Results: Studies suggest there may be a construct that is distinct from self-reported fatigue, reflecting a new potential intervention target. However, assessments vary and findings across and within measures are inconsistent. Few measures have been guided by a coherent theory, and those identified are likely to be influenced by other confounds, such as cognitive impairment caused more directly by disease processes, depression and assessment biases. Conclusion: Future research may benefit from (a) developing a guiding theory of cognitive fatigability, (b) examining ecological and construct validity of existing assessments and (c) exploring whether the more promising cognitive fatigability measures are correlated with impaired functioning after accounting for possible confounds. Given the issues raised, we caution that our purposes as researchers may be better served by continuing our search for a more objective cognitive fatigability construct that runs in parallel with improving, rather than devaluing, current PROs

A Candidate Dual Active Galactic Nucleus At Z=1.175

The X-ray source CXOXBJ142607.6+353351 (CXOJ1426+35), which was identified in a 172 ks Chandra image in the Bootes field, shows double-peaked rest-frame optical/UV emission lines, separated by 0.''69 (5.5 kpc) in the spatial dimension and by 690 km s(-1) in the velocity dimension. The high excitation lines and emission line ratios indicate both systems are ionized by an active galactic nucleus (AGN) continuum, and the double-peaked profile resembles that of candidate dual AGNs. At a redshift of z = 1.175, this source is the highest redshift candidate dual AGN yet identified. However, many sources have similar emission line profiles for which other interpretations are favored. We have analyzed the substantial archival data available in this field as well as acquired near-infrared (NIR) adaptive optics (AO) imaging and NIR slit spectroscopy. The X-ray spectrum is hard, implying a column density of several 10(23) cm(-2). Though heavily obscured, the source is also one of the brightest in the field, with an absorption-corrected 2-10 keV luminosity of similar to 10(45) erg s(-1). Outflows driven by an accretion disk may produce the double-peaked lines if the central engine accretes near the Eddington limit. However, we may be seeing the narrow line regions of two AGNs following a galactic merger. While the AO image reveals only a single source, a second AGN would easily be obscured by the significant extinction inferred from the X-ray data. Understanding the physical processes producing the complex emission line profiles seen in CXOJ1426+35 and related sources is important for interpreting the growing population of dual AGN candidates.National Science Foundation AST-0708490Strategic University Research Partnership ProgramNational Aeronautics and Space AdministrationW. M. Keck FoundationSmithsonian Astrophysical Observatory SV4-74018, A31Astronom

Magnetic tight-binding and the iron-chromium enthalpy anomaly

We describe a self consistent magnetic tight-binding theory based in an expansion of the Hohenberg-Kohn density functional to second order, about a non spin polarised reference density. We show how a first order expansion about a density having a trial input magnetic moment leads to the Stoner--Slater rigid band model. We employ a simple set of tight-binding parameters that accurately describes electronic structure and energetics, and show these to be transferable between first row transition metals and their alloys. We make a number of calculations of the electronic structure of dilute Cr impurities in Fe which we compare with results using the local spin density approximation. The rigid band model provides a powerful means for interpreting complex magnetic configurations in alloys; using this approach we are able to advance a simple and readily understood explanation for the observed anomaly in the enthalpy of mixing.Comment: Submitted to Phys Rev

Outlining an Acceptance and Commitment Therapy approach to treatment non-adherence

Non-adherence to effective treatments - inclusive of medications, physiotherapy, and psychological interventions – is a significant problem in healthcare delivery. The World Health Organisation reported an non-adherence rate of 30-50% in people taking medication for long-term conditions (Sabaté, 2003), which leads to significant adverse clinical, social and financial impacts (Khan & Socha-Dietrich , 2018). This problem is not restricted to medications. For example, uptake of pulmonary rehabilitation groups for COPD (Garrod, Marshall, Barley, & Jones, 2006) and psychological therapy groups for mental health conditions are often sub-optimal (Brebach, Sharpe, Costa, Rhodes, & Butow, 2016; Byrne et al., 2019; Michelson & Sclare, 2009). Despite extensive research on the causes of non-adherence (Kardas, Lewek, & Matyjaszczyk, 2013) and the evaluation of interventions (Conn, Ruppar, Enriquez, & Cooper, 2016), the challenge of non-adherence is still very much present