PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “cluster analysis”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 703 records · Page 39Linked to original sources
PubMed1985

A cluster analysis of Million Clinical Multiaxial Inventory (MCMI) profiles: more about a taxonomy of alcoholic subtypes.

MCMI and MMPI data were obtained from 125 male veteran alcoholic inpatients. MCMI profiles were classified into five relatively homogeneous subgroups by a hierarchical clustering technique. One-way ANOVAs were calculated for each of the MMPI scales; patients were classified according to MCMI group membership. Results showed that conceptually meaningful clusters exist among MCMI profiles, that statistically significant relationships exist between MCMI profiles and MMPI scale scores, and that these relationships are consistent with trends reported in the literature. The study provides additional support for the idea that a potentially useful taxonomy exists for alcoholics and suggests that the MCMI could be a useful tool in subsequent research on understanding and treating different patterns of alcoholism.

Adult↗
PubMed1999

Cluster analysis and finite-size scaling for Ising spin systems.

Based on the connection between the Ising model and a correlated percolation model, we calculate the distribution function for the fraction (c) of lattice sites in percolating clusters in subgraphs with n percolating clusters, f(n)(c), and the distribution function for magnetization (m) in subgraphs with n percolating clusters, p(n)(m). We find that f(n)(c) and p(n)(m) have very good finite-size scaling behavior and that they have universal finite-size scaling functions for the model on square, plane triangular, and honeycomb lattices when aspect ratios of these lattices have the proportions 1:square root[3]/2:square root[3]. The complex structure of the magnetization distribution function p(m) for the system with large aspect ratio could be understood from the independent orientations of two or more percolation clusters in such a system.

Journal Article↗
PubMed1987

[Factor and cluster analysis on the study of mimetic communication in monkeys].

The mimics elements, typical mimic complexes and frequency of mimics display in different behavioral contexts in representatives of 10 species of monkeys and apes have been investigated. The methods of factor and cluster analyses have been applied to reveal a connection between mimics and phylogenetical level of the species. A dendrogram of interspecies relationships is presented. The type of species social structure is one of the main factors in mimic communication development.

Animal Communication↗
PubMed2025

Premorbid functioning trajectories and the one-year course of cognitive performance in first-episode psychosis: a cluster analysis in PSYSCAN.

BACKGROUND: We examined the course of cognitive performance in first-episode psychosis (FEP) compared to healthy controls (HC), and whether this varied across subgroups of patients defined by premorbid functioning (PMF) trajectories, using a clustering approach. METHODS: Data were collected in 302 FEP and 136 HC subjects participating in PSYSCAN (HEALTH.2013.2.2.1-2-FEP). K-means clustering (Euclidean distance) was used to cluster longitudinal trajectories of different PMF domains simultaneously. Since PMF was assessed retrospectively using the Premorbid Adjustment Scale (PAS), findings should be interpreted with caution, although PAS ratings have shown reasonable validity against prospective data. RESULTS: As expected, FEP showed impaired performance across all cognitive domains compared to HC. We identified four trajectories of PMF: a normal premorbid developmental trajectory (globally-normal, 21 %), stable intermediate PMF across domains (stable-intermediate, 29 %), stable poor or deteriorating PMF in the academic domain (normal-social/poor-academic, 29 %), and a globally impaired group with poor/deteriorating PMF across domains (globally-poor, 21 %). These clusters showed distinct levels of post-onset impairments in sustained visual attention, visual working memory and emotion recognition. CONCLUSIONS: This study confirms a positive association between PMF and cognitive performance in the early years following psychosis onset. It aligns with findings that individuals later diagnosed with schizophrenia already show developmental deficits/lags from childhood to early adolescence compared to normally developing children. As PMF can be considered a proxy for cognitive reserve, our results suggest that higher reserve acts as a buffer against cognitive decline and supports better performance on sustained visual attention, complex visual working memory, and aspects of emotion recognition.

Clustering↗
PubMedDate not supplied

Hierarchical cluster analysis of emotional concerns and personality characteristics in a freshman population.

An investigation was conducted to examine correlates of emotional concerns and personality characteristics in a general freshman population. The scores were analysed using agglomerative and divisive hierarchical clustering methods. The results indicate the presence of a coherent group which concerns emotional factors, and show a distinct user group strongly related to the first group. The data do not determine the importance of various personality factors in influencing emotional concerns.

Adolescent↗
PubMed2006

Ultrafast dynamics in atomic clusters: analysis and control.

We present a study of dynamics and ultrafast observables in the frame of pump-probe negative-to-neutral-to-positive ion (NeNePo) spectroscopy illustrated by the examples of bimetallic trimers Ag2Au-/Ag2Au/Ag2Au+ and silver oxides Ag3O2-/Ag3O2/Ag3O2+ in the context of cluster reactivity. First principle multistate adiabatic dynamics allows us to determine time scales of different ultrafast processes and conditions under which these processes can be experimentally observed. Furthermore, we present a strategy for optimal pump-dump control in complex systems based on the ab initio Wigner distribution approach and apply it to tailor laser fields for selective control of the isomerization process in Na3F2. The shapes of pulses can be assigned to underlying processes, and therefore control can be used as a tool for analysis.

Journal Article↗
PubMed1988

Empirically derived Symptom Checklist 90 subgroups of chronic pain patients: a cluster analysis.

Four hundred fifty-three chronic pain patients completed a Symptom Checklist 90 (SCL-90) and a comprehensive pain evaluation questionnaire. All patients were evaluated by a physician and rated on degree of pain pathology and pain behavior. The SCL-90 data were analyzed using two clustering procedures and replicated over two similar samples. Three distinct profiles emerged and represented high, medium, and low scores on the SCL-90. No differences were found between subgroups on demographic characteristics, compensation status, pain duration, or pain ratings. Patients in the high-profile subgroup showed the most emotional distress, reported that their pain interfered the most with all activities, and were most often judged to have high pain behavior. Little evidence was found to support a "denial" profile, as previously predicted. Further support was found for using the SCL-90 in assessing chronic pain patients.

Activities of Daily Living↗
PubMed1985

[Functional interrelations of brain structures in the cat during the generation of rhythmic activity. III. Cluster analysis of rhythmic indices].

The functional interrelationships of the brain structures of freely moving cats in generation of rhythmic EEG activity during the states of drowsiness and light sleep were evaluated using the claster analysis of mean values indexes of rhythms in different structures as well as correlation coefficients between them in time. It was shown that according these parameters visual cortical areas and lateral geniculate body appeared in different clusters. Lateral geniculate body suggested not to be the only pacemaker of EEG rhythms in visual cortex. The wide convergence of subcortical inputs to the visual cortex and possibility of autonomic generation of EEG rhythms at the cortical level are discussed as putative mechanisms of dissociation of EEG activities in visual cortex and thalamus.

Animals↗