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Objectives: The Wisconsin Card Sorting Test (WCST) is a complex measure of executive function that is frequently employed to investigate the schizophrenia spectrum. The successful completion of the task requires the interaction of multiple intact executive processes, including attention, inhibition, cognitive flexibility, and concept formation. Considerable cognitive heterogeneity exists among the schizophrenia spectrum population, with substantive evidence to support the existence of distinct cognitive phenotypes. The within-group performance heterogeneity of individuals with schizophrenia spectrum disorder (SSD) on the WCST has yet to be investigated. A data-driven cluster analysis was performed to characterise WCST performance heterogeneity. Methods: Hierarchical cluster analysis with k-means optimisation was employed to identify homogenous subgroups in a sample of 210 schizophrenia spectrum participants. Emergent clusters were then compared to each other and a group of 194 healthy controls (HC) on WCST performance and demographic/clinical variables. Results: Three clusters emerged and were validated via altered design iterations. Clusters were deemed to reflect a relatively intact patient subgroup, a moderately impaired patient subgroup, and a severely impaired patient subgroup. Conclusions: Considerable within-group heterogeneity exists on the WCST. Identification of subgroups of patients who exhibit homogenous performance on measures of executive functioning may assist in optimising cognitive interventions. Previous associations found using the WCST among schizophrenia spectrum participants should be reappraised. (JINS, 2019, 25, 750–760)
We present a revised chronology for the Kolomoki site (9ER1) in Georgia, occupied primarily during the Middle and Late Woodland periods (ca. 200 BC to AD 1050). The considerable extent of the site has been noted for more than a century but came into sharper focus with the archaeological investigations by Sears (1956) and Pluckhahn (2003). The site includes at least nine mounds, a large central plaza, and a discontinuous habitation area nearly a kilometer in diameter. Previous interpretations assumed gradual and incremental changes in the community plan. We present a greatly revised chronology, based on new investigations in some of the lesser-known portions of the site and a doubling of the number of absolute dates. Bayesian modeling of these and previous dates reveals that, far from the gradualist assumption of previous work, the community at Kolomoki was dynamically transformed several times in its history, reaching its greatest spatial extent and formal complexity in two relatively short-lived phases. In these intervals, the village incorporated permanent residents and visitors into a single community in which daily face-to-face interactions were minimized even as communal identity was celebrated.
Current group-average analysis suggests quantitative but not qualitative cognitive differences between schizophrenia (SZ) and bipolar disorder (BD). There is increasing recognition that cognitive within-group heterogeneity exists in both disorders, but it remains unclear as to whether between-group comparisons of performance in cognitive subgroups emerging from within each of these nosological categories uphold group-average findings. We addressed this by identifying cognitive subgroups in large samples of SZ and BD patients independently, and comparing their cognitive profiles. The utility of a cross-diagnostic clustering approach to understanding cognitive heterogeneity in these patients was also explored.
Hierarchical clustering analyses were conducted using cognitive data from 1541 participants (SZ n = 564, BD n = 402, healthy control n = 575).
Three qualitatively and quantitatively similar clusters emerged within each clinical group: a severely impaired cluster, a mild-moderately impaired cluster and a relatively intact cognitive cluster. A cross-diagnostic clustering solution also resulted in three subgroups and was superior in reducing cognitive heterogeneity compared with disorder clustering independently.
Quantitative SZ–BD cognitive differences commonly seen using group averages did not hold when cognitive heterogeneity was factored into our sample. Members of each corresponding subgroup, irrespective of diagnosis, might be manifesting the outcome of differences in shared cognitive risk factors.
Interactions with the bodies of hunted animals often follow prescriptions pertaining to social relationships among human and non-human persons. Despite this, deposits of archaeological food remains are seldom considered in terms of deliberate placement, instead serving primarily as reflections of preparation and consumption activities. The residues of feasts, in particular, are often highlighted as indexes of special consumption events, although such salient occasions might also be expected to highlight ritualized depositional practices as well. This study reconsiders the archaeological residues of feasts through the vantage of a fauna-filled pit in late Pre-Columbian Florida. Most of the contents of the feature correlate with a large feast, but the structure of the deposit and inclusion of specific elements reflects scrupulous emplacement. Drawing on North American relational ontologies, we explore the idea that this pit feature was created as a deliberate bundle, the result of an intentional act of interment that was concerned with positioning its contents in ways that manifested and shaped various relationships.
The understanding of the crystallization of aluminosilicate phases in nuclear waste glasses is a major challenge for nuclear waste vitrification. Robust studies on the compositional dependence of nepheline formation have focused on large compositional spaces with hundreds of glass compositions. However, there are clear benefits to obtaining complete descriptions of the conditions under which crystallization occurs for specific glasses, adding to the understanding of nucleation and growth kinetics and interfacial conditions. The focus of this work was the investigation of the microstructure and composition of one simulant high-level nuclear waste glass crystallized under isothermal and continuous cooling schedules. It was observed that conditions of low undercooling, nepheline was the most abundant aluminosilicate phase. Further undercooling led to the formation of additional phases such as calcium phosphate. Nepheline composition was independent of thermal history.
The determination of the long-term stability and corrosion of vitrified nuclear waste is an important aspect of research for the U.S. Department of Energy (DOE). It is necessary to understand the rate and mechanisms of Nuclear Waste Glass (NWG) corrosion to determine whether or not the glassy matrix will be able to retain radionuclides for the required repository performance time period. Glass corrosion and the rate of glass corrosions is determined by both chemical and microscopy. Electron Microprobe Analysis (EPMA) is a common and powerful method utilized in the examination of the chemographic difference between corroded and uncorroded NGWs. In this work, two forms of quantitative and semi-quantitative EPMA methods are defined by optimizing the instruments counting statistics against a standard glass and NIST minerals that have compositions similar to the glasses under examination. Data collected on both the planar and cross-sectioned surfaces of an unaltered simulated NWG by Standard based Wavelength Dispersive Spectroscopy (WDS) was found to be comparable to the theoretical composition of the glass. Conventional standardless Energy Dispersive Spectroscopy (EDS) data collected on the same surfaces was not comparable. However, standard-based EDS analysis is shown to be able to discriminate between unaltered and corroded glass surfaces.
A complete understanding of radioactive waste glass interactions with near-field materials is essential for appropriate nuclear waste repository performance assessment. In many geologic repository designs, Fe is present both in the natural environment and in the containers that will hold the waste glasses. In this paper we discuss investigations of the alteration of International Simple Glass (ISG) in the presence of Fe0 foil and hematite (Fe2O3). Based on solid analysis, ISG alteration is more pronounced in the presence of Fe0 than with hematite. Additionally, typical glass corrosion is observed for distances of 5 mm between Fe materials and ISG, but incorporation of Fe in the alteration layer is only observed for systems exhibiting full contact between Fe0 material and ISG. Solution analysis results indicate that diatomaceous earth minimizes corrosion to a larger extent than fumed silica does when present with iron and ISG.
Serial assessments are commonplace in neuropsychological practice and used to document cognitive trajectory for many clinical conditions. However, true change scores may be distorted by measurement error, repeated exposure to the assessment instrument, or person variables. The present study provides reliable change indices (RCI) for the Boston Naming Test, derived from a sample of 844 cognitively normal adults aged 56 years and older. All participants were retested between 9 and 24 months after their baseline exam. Results showed that a 4-point decline during a 9–15 month retest period or a 6-point decline during a 16–24 month retest period represents reliable change. These cutoff values were further characterized as a function of a person's age and family history of dementia. These findings may help clinicians and researchers to characterize with greater precision the temporal changes in confrontation naming ability. (JINS, 2012, 18, 375–378)
The electrical and physical quality of gate and passivation dielectrics significantly impacts the device performance of thin film transistors (TFTs). The passivation dielectric also needs to act as a barrier to protect the TFT device. As low temperature TFT processing becomes a requirement for novel applications and plastic substrates, there is a need for materials innovation that enables high quality plasma enhanced chemical vapor deposition (PECVD) gate dielectric deposition. In this context, this paper discusses structure-property relationships and strategies for precursor development in silicon nitride, silicon oxycarbide (SiOC) and silicon oxide films. Experiments with passivation SiOC films demonstrate the benefit of a superior precursor (LkB-500) and standard process optimization to enable lower temperature depositions. For gate SiO2 deposition (that are used with polysilicon TFTs for example), organosilicon precursors containing different types and amounts of Si, C, O and H bonding were experimentally compared to the industry standard TEOS (tetraethoxysilane) at different process conditions and temperatures. Major differences were identified in film quality especially wet etch rate or WER (correlating to film density) and dielectric constant (k) values (correlating to moisture absorption). Gate quality SiO2 films can be deposited by choosing precursors that can minimize residual Si-OH groups and enable higher density stable moisture-free films. For e.g., the optimized precursor AP-LTO® 770 is clearly better than TEOS for low temperature PECVD depositions based on density, WER, k charge density (measured by flatband voltage or Vfb); and leakage and breakdown voltage (Vbd) measurements. The design and development of such novel precursors is a key factor to successfully enable manufacturing of advanced low temperature processed devices.
Scores on the Boston Naming Test (BNT) are frequently lower for African American when compared with Caucasian adults. Although demographically based norms can mitigate the impact of this discrepancy on the likelihood of erroneous diagnostic impressions, a growing consensus suggests that group norms do not sufficiently address or advance our understanding of the underlying psychometric and sociocultural factors that lead to between-group score discrepancies. Using item response theory and methods to detect differential item functioning (DIF), the current investigation moves beyond comparisons of the summed total score to examine whether the conditional probability of responding correctly to individual BNT items differs between African American and Caucasian adults. Participants included 670 adults age 52 and older who took part in Mayo’s Older Americans and Older African Americans Normative Studies. Under a two-parameter logistic item response theory framework and after correction for the false discovery rate, 12 items where shown to demonstrate DIF. Of these 12 items, 6 (“dominoes,” “escalator,” “muzzle,” “latch,” “tripod,” and “palette”) were also identified in additional analyses using hierarchical logistic regression models and represent the strongest evidence for race/ethnicity-based DIF. These findings afford a finer characterization of the psychometric properties of the BNT and expand our understanding of between-group performance. (JINS, 2009, 15, 758–768.)
A central role for neuropsychological evaluations is the measurement
of change in cognitive functioning over time. However, change scores
obtained from repeated neuropsychological assessments may be affected by
normal variability because of measurement error and practice effects
caused by repeated measurements. The current study uses reliable change
estimates to establish normative rates of change on the Dementia Rating
Scale from baseline to first follow-up testing among 1080 cognitively
normal adults aged 65 and older. Results showed that a 6-point decline by
European Americans or a 9-point decline by African American adults within
a 9–15 month test-retest interval represents reliable change. Within
a 16–24-month test-retest interval, a 7-point decline among European
Americans or an 8-point decline among African American adults represents
reliable change. In addition, preliminary cross-validation was performed
in a clinical comparison sample of another 22 older adults. The findings
are discussed in the context of potential clinical and research
applications. (JINS, 2007, 13, 716–720.)
Growth failure is a common yet complex problem of childhood chronic kidney disease caused by multiple factors encountered due to the primary disease or secondary to the renal impairment. This review seeks to describe the various patho-physiological mechanisms contributing to growth failure in the various stages of childhood with particular emphasis on nutritional problems and endocrine dysfunction encountered whilst managing these children. In addition, we shall examine the role of body composition in chronic kidney disease, their relationship with growth and nutrition and the potential effect of abnormalities in fat mass and lean mass on long-term morbidity and mortality.
Covariance structure analyses of a core neuropsychological test
battery consisting of the Wechsler Adult Intelligence Scale–Revised,
Wechsler Memory Scale–Revised, and Auditory Verbal Learning Test
have previously identified a 5-factor model in a sample of cognitively
normal White volunteers from Mayo's Older Americans Normative Studies
(MOANS). The present study sought to replicate this factor structure in a
sample of 289 cognitively normal, community-dwelling African American
elders from Mayo's Older African Americans Normative Studies
(MOAANS). The original 5-factor model was tested against 2 alternative
4-factor models and a 6-factor model generated on a substantive basis.
Confirmatory factor analysis supported the construct validity of this core
battery in older African Americans by replicating the original 5-factor
model of Verbal Comprehension, Perceptual Organization,
Attention/Concentration, Learning, and Retention as viable in the
present sample. (JINS, 2005, 11, 184–191.)
The relationship between apolipoprotein E (apoE) genotype and
cognitive performance was examined in 200 patients with probable
Alzheimer's disease (AD). Differences between composite
measures of verbal and nonverbal functioning were used to define
asymmetric patterns of cognition. Patients who were homozygous
for apoE ε4 demonstrated relatively worse nonverbal as compared
to verbal cognitive ability. In contrast, participants who were
heterozygous for apoE ε4 or who possessed no ε4 allele
demonstrated relatively equivalent verbal and nonverbal cognitive
abilities. Although age and dementia severity also contributed
to these patterns, apoE genotype appears to have a significant
unique contribution to cognitive performance in these individuals.
The ε4 allele may thus be associated with a specific
neurocognitive phenotype among patients with AD, with the overall
pattern of cognitive asymmetry dependent upon ε4 dose.
(JINS, 2003, 9, 751–759.)
We present the results of two imaging surveys for companions to low-luminosity dwarfs, one with Keck to a limiting magnitude of K = 20, and the other with HST to a limiting magnitude of I = 23. No companions were found at separations of 0″.5 to 20″.0, but seven companions were found within 0″.5. Based on sub-stellar evolutionary models, we estimate the companion detection efficiency as a function of mass ratio. This modeling, coupled with the data, place strong upper limits on the mass ratios of unobserved companions. We conclude that no companions exist in the optimal sensitivity regions of both surveys for q > 0.85 (HST), and q > 0.4 (Keck).
Rapid eye movement (REM) sleep behavior disorder (RBD) is a
sleep disturbance that commonly occurs in Dementia with Lewy
bodies (DLB). Retrospective examination of DLB course has shown
that RBD and cognitive decline may precede the onset of
parkinsonism and visual hallucinations. Therefore, some patients
with DLB may initially present with dementia and RBD, but would
not meet current formal criteria for probable DLB at that time.
The purpose of this study is to determine whether patients with
dementia and RBD, who do not have parkinsonism or visual
hallucinations, have cognitive profiles that can be distinguished
from autopsy-confirmed definite AD, but not from clinically
probable DLB. If so, this would support the hypothesis that
the presence of RBD and dementia, as the only presenting symptoms,
reflects the early manifestation of DLB. Results show that early
dementia in probable DLB and dementia with RBD are
neuropsychologically indistinguishable. Both groups differ from
definite AD of a similar early stage with significantly worse
visual perceptual organization, sequencing and letter fluency
but significantly better confrontation naming and verbal memory.
In addition, follow-up data from a subset of patients with dementia
and RBD reveal the subsequent development of parkinsonism or
hallucinations 1 to 6 years later. Results indicate that the
presentation of dementia and RBD is suggestive of underlying
Lewy body disease and not Alzheimer's disease. This provides
further evidence in support of including RBD as one of the core
diagnostic features of DLB. (JINS, 2002, 8, 907–914.)
In field trials conducted in 1989 and 1990, fifteen postemergence herbicides were tested for phytotoxicity to kenaf. Clethodim (110 g ai ha–1), fluazifop (220 g ai ha–1), quizalofop (70 g ai ha–1), and sethoxydim (210 g ai ha–1) were not phytotoxic to kenaf in the cotyledonary stage. MSMA (2.2 kg ha–1) was not phytotoxic to kenaf at the cotyledonary or 35-cm stage. All other herbicides applied postemergence to kenaf caused significant injury.
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