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PubMed1983

Classification of schizo-affective patients by multidimensional scaling and cluster analysis.

269 patients with schizophrenia, schizo-affective or affective disorders admitted to a hospital in Zürich were examined by the AMP system and the syndrome checklist of Wing and co-workers. The data were analyzed using a special set-theoretical similarity measure for nonlinear graduations, multidimensional scaling to achieve a metric representation of the similarity matrices, and a cluster analysis, originally described by Meisel in 1972.

Bipolar Disorder↗
PubMed1995

Hydrophobic cluster analysis and secondary structure predictions revealed that major and minor structural subunits of K88-related adhesins of Escherichia coli share a common overall fold and differ structurally from other fimbrial subunits.

The structural relatedness of K88-related major and minor subunits was deduced from their sequences by hydrophobic cluster analysis (HCA) and secondary structure predictions produced by the profile neural network prediction program (PHD) on multiple sequence alignments. Although the weak residue identity between major and minor subunits is evidence of a high evolutionary distance, an overall structural similarity was observed In addition, clear amphipathic conformations were conserved in predicted secondary structure. On the basis of this predicted structural similarity, a schematic 2D model of ClpG subunit was developed.

Amino Acid Sequence↗
PubMed1984

Cluster analysis of genes in codon space.

We construct a "codon space" in which a given DNA sequence can be plotted as a function of its base composition in each of the three codon positions. We demonstrate that the base composition is very highly nonrandom, with sequences from more primitive organisms having the least random compositions. By using cluster analysis on the points plotted in codon space we show that there is a strong correlation between base composition and type of organism, with the most primitive organisms having the highest A or T content in the second and third codon positions. A smooth transition toward lower A + T and higher G + C content is observed in the second and third codon positions as the evolutionary complexity of the organism increases. Besides this general trend, more detailed structure can be observed in the clustering that will become clearer as the data base is increased.

Bacteriophages↗
PubMed2000

Determination of generic body-seat interface shapes by cluster analysis.

The purpose of this study was to determine typical or generic shape patterns of the buttock-seat interface for elderly wheelchair users. The group of subjects was composed of 30 elderly people (aged 65 or older) and the shapes of the body-seat interface were measured by the electronic shape sensor (ESS). By analyzing the dissimilarity in geometrical shape descriptors or parameters, four distinct generic shapes were identified by means of the cluster analysis method. The results suggest that the generic shapes were mainly characterized by the lateral symmetry of the shapes. The determination of elderly people's seat interface shapes into distinct clusters may lead to a more comprehensive understanding of the seat support interface and more effective seat cushion designs.

Aged↗
PubMed2006

Morphological development of Aspergillus niger in submerged citric acid fermentation as a function of the spore inoculum level. Application of neural network and cluster analysis for characterization of mycelial morphology.

BACKGROUND: Although the citric acid fermentation by Aspergillus niger is one of the most important industrial microbial processes and various aspects of the fermentation appear in a very large number of publications since the 1950s, the effect of the spore inoculum level on fungal morphology is a rather neglected area. The aim of the presented investigations was to quantify the effects of changing spore inoculum level on the resulting mycelial morphology and to investigate the physiology that underlines the phenomena. Batch fermentations were carried out in a stirred tank bioreactor, which were inoculated directly with spores in concentrations ranging from 10(4) to 10(9) spores per ml. Morphological features, evaluated by digital image analysis, were classified using an artificial neural network (ANN), which considered four main object types: globular and elongated pellets, clumps and free mycelial trees. The significance of the particular morphological features and their combination was determined by cluster analysis. RESULTS: Cell volume fraction analysis for the various inoculum levels tested revealed that by rising the spore inoculum level from 10(4) to 10(9) spores per ml, a clear transition from pelleted to dispersed forms occurs. Glucosamine formation and release by the mycelium appears to be related to spore inoculum level. Maximum concentrations detected in fermentations inoculated with 10(4) and 10(5) spores/ml, where pellets predominated. At much higher inoculum levels (10(8), 10(9) spores/ml), lower dissolved oxygen levels during the early fermentation phase were associated with slower ammonium ions uptakes and significantly lower glucosamine concentrations while the mycelium developed in dispersed morphologies. A big increase in the main and total hyphal lengths and branching frequency was observed in mycelial trees as inoculum levels rise from 10(4) to 10(9) spores/ml, while in aggregated forms particle sizes and their compactness decreased. CONCLUSION: The methods used in this study, allowed for the detailed quantification of the transition between the two extreme morphological forms. The impact of spore inoculum level on the detailed characteristics of the particular morphological forms produced was high. Control of mycelial morphology is often regarded as a prerequisite to ensure increased productivities in industrial applications. The research described here demonstrates that adjusting the spore inoculum level controls effectively mycelial morphology.

Journal Article↗
PubMed1984

[Cluster analysis of alcoholic patients based on personality variables, social insecurity and control orientation].

200 alcoholics from 6 clinics with different therapeutic orientations were tested with the Freiburg Personality Inventory (Fahrenberg et al. 1978), an assertiveness-inventory (Ullrich u. Ullrich 1977), and a translated version of the Levenson (1973)-Locus of Control. On the base of a hierarchical-agglomerative cluster analysis four types of patients were suggested: 1) An aggressive-depressive, 2) a depressive-social anxious external controlled, 3) an assertive, 4) and a high stable alcoholic with well-balanced mood and internal control. The highest changes of generalized variance in a stepwise discriminant analysis were found on depression, misfortune-anxiety, impulsivity and control by powerful others. The reclassification rate was 85.5%. Out of 24 biographical data no one differed between the groups. The hypotheses of a population variation over different clinics was not supported. Differential therapeutic indications for the groups were discussed.

Alcoholism↗
PubMed1990

The identification of psychiatric disorders in children who fail to attend school: a cluster analysis of a non-clinical population.

Interviews were conducted with parents of 100 children taken to a 'school attendance committee', because of persistent failure to attend school. Clinical assessment of the attendance problem was carried out so that children were categorized as 'school refusers' (N = 24), 'truants' (N = 53), 'both refusers and truants' (N = 9), or as 'neither' (N = 14). Any ICD-9 psychiatric disorder was separately identified. Cluster analysis of information collected in a standard way indicated that there was a group of children with the features of 'school refusal' who often had generalized neurotic disorders as well and who were mostly girls, another group with the features of 'truancy' all of whom had conduct disorders who were mainly boys, and a third cluster of children who were usually 'truants' but less often psychiatrically disturbed. The study provided evidence for the existence of school refusal with and without generalized neurotic disturbance in a non-clinical population.

Absenteeism↗
PubMed1988

Typology of mood assessment curves by means of cluster analysis of computerized mathematical descriptions of time-series mood data collected from depressive inpatients treated with antidepressants.

A recently developed method for the computerized description of mood curves was applied to self-evaluation mood data of a large sample of 136 depressive inpatients. The values of the mathematical parameters from this description were analysed by cluster analysis to determine different types of mood courses of patients undergoing therapy with antidepressants. In general, the most unfavorable type of mood course was overrepresented in the group of neurotic depressive patients, the most favorable one in the group of endogenous depressive patients. But in this latter diagnostic group, a remarkable proportion of patients with the unfavorable mood course was observed, indicating the well-known phenomenon of non-response to antidepressants. The results can be interpreted as a validation of the new method of computerized description of mood curves. This method might lead to interesting possibilities in drug treatment evaluation.

Antidepressive Agents↗
PubMed1986

Cluster analysis of food consumption patterns of older Americans.

This study uses data from the 1977-78 Nationwide Food Consumption Survey (NFCS) to develop a classification scheme for differentiating individuals into groups that have similar patterns of food consumption. The article examines the nutritional adequacy of those food patterns and identifies the socioeconomic factors associated with each pattern. Cluster analysis is used to identify the food consumption patterns of a nationally representative sample of persons aged 65 through 74 years. The results indicate that the food patterns of older persons can be well categorized as light eaters, heavy eaters, or consumers of large amounts of alcoholic beverages, salty snack products, animal fat products, legumes, or sweets and desserts. Following those different food patterns leads to noteworthy differences in nutrient intakes. Ethnic group membership and residence status are found to be the most important socioeconomic factors associated with differences in the food patterns followed.

Aged↗
PubMed1982

[High-risk groups in pre-school children. Cluster analysis (author's transl)].

A 3 years supervision of 415 pre-school children was undertaken in Paris from 1974 to 1977. Four epidemiological sets of questions provided information on the familial and social situation as well as on the physical and psychological development of the child at 3, 9, 18 and 36 months of age. A cluster analysis was applied to the behavior and health variables in the 3 year-old child and 3 different groups were identified. Most children (69%) belong to the first group, characterized by the absence of difficulties or the presence of a few minor symptoms, 10% of the children belong to the third group, a "high risk group" because of their high frequency of symptoms. Half-way between these 2 groups, a "low-risk group" (21%) was identified. The reliability of this analysis was further supported by the study of the families (especially their social and economic status and the parents' mental health). This study also revealed the early onset of the symptoms in high risk children.

Behavior↗
PubMed2005

Applications of hierarchical cluster analysis (CLA) and principal component analysis (PCA) in feed structure and feed molecular chemistry research, using synchrotron-based Fourier transform infrared (FTIR) microspectroscopy.

Synchrotron technology based Fourier transform infrared microspectroscopy (S-FTIR) is a recently emerging bioanalytical microprobe capable of exploring the molecular chemistry within microstructures of feed tissues at a cellular or subcellular level. To date there has been very little application of hierarchical cluster analysis (CLA) and principal component analysis (PCA) to the study of feed inherent microstructures and feed molecular chemistry between feeds and/or between different structures within a feed, in relation to feed quality and nutrient availability using S-FTIR. In this paper, multivariate statistical methods--CLA and PCA--were used to analyze synchrotron-based FTIR individual spectra obtained from feed inherent microstructures within intact tissues by using the S-FTIR as a novel approach. The S-FTIR spectral data of three feed inherent structures (strucutre 1, feed pericarp; structure 2, feed aleurone; structure 3, feed endosperm) and different varieties of feeds within cellular dimensions were collected at the National Synchrotron Light Source (NSLS) at Brookhaven National Laboratory (BNL), U.S. Department of Energy (NSLS-BNL, New York). Both PCA and CLA methods gave satisfactory analytical results and are conclusive in showing that they can discriminate and classify inherent structures and molecular chemistry between and among the feed tissues. They also can be used to identify whether differences exist between the varieties. These statistical analyses place synchrotron-based FTIR microspectroscopy at the forefront of those new potential techniques that could be used in rapid, nondestructive, and noninvasive screening of feed intrinsic microstructures and feed molecular chemistry in relation to the quality and nutritive value of feeds.

Analysis of Variance↗
PubMed1987

Cluster analysis of antibiotic susceptibility patterns of clinical isolates as a tool in nosocomial infection surveillance.

Hospital infections represent a major epidemiological problem. The first step in the detection of nosocomial infections consists in assessing the probability that two or more isolates from different patients are similar or different. Many methods are available for typing purposes. Among these, antibiotic susceptibility patterns do not need extra cost or extra work and are available "on line" every moment they are needed. A mathematical technique of elaboration is proposed for disk zone sizes, in order to assess the probability of two or more clinical isolates to be the same strain. Antibiograms performed according to Kirby-Bauer are evaluated detecting zone sizes by a computer controlled device and then submitted to cluster analysis. Similarity of strains is reported in a dendrogram, in which strains are successively fused. Strains that share a common susceptibility pattern are considered a "cluster". At last, epidemiological maps are constructed for each group of strains, in which all the isolates are reported, ordered for patients, plotted on the day the specimen was collected, drawn in a different shape according to the source of specimen, and shadowed by the pattern of its cluster. This method of reporting data directly allows to detect cross infections among patients and can be used as a first typing step before other more expensive procedures.

Anti-Bacterial Agents↗
PubMed1984

[Study of the process of alcoholism in young persons using cluster analysis].

An epidemiological survey was carried out among high school students of 3 French regions. Their use of drugs (alcohol, tobacco, psychotropic drugs, illicit drugs) was studied, as well as their self-perception of personality, relations inside and outside the family, school performance, and lifestyle. Different aspects of drinking were considered: regularity of intake, quantity absorbed, inebriation. The use of alcoholic drinks together with psychotropic substances was studied. A cluster analysis applied to adolescent personality self-perception revealed 10 different personality types (5 for the boys; 5 for the girls). The social, family, and relational characteristics of each personality type are described. The correlations between personality self-perception and liquor use allow us to define 3 profiles of heavy drinkers.

Achievement↗
PubMed2005

Scoring of visual field measured through Humphrey perimetry: principal component varimax rotation followed by validated cluster analysis.

PURPOSE: To extract unidimensional, well-separated latent scores that are anatomically and clinically valid from 52 standardized variables collected by Humphrey visual field (VF) perimetry (Carl Zeiss Meditec, Dublin, CA). METHODS: Visual field data of 437 patients were collected and classified by a glaucoma specialist into seven clinical groups: irregularities of VF (IVF), nasal step (NaS), arcuate scotoma (AC), paracentral scotoma (PCS), blind-spot enlargement (BSE), diffuse deficit (DD), and advanced deficit (AD). The number and content of constituent variable scores were identified by principal components analysis followed by Varimax Rotation and simple clustering, taking spatial distribution homogeneity and visual system anatomy into account. Unidimensionality was checked by a stepwise Cronbach alpha curve. Clinical predictability of the derived scores was checked by comparing clinical groups (ANOVA). RESULTS: Patients older than 60 years comprised 53.3% of the sample. The average mean deviation was -9.2 dB and pattern standard deviation was 6.5 dB. Six scores were identified: four peripheral scores (nasal superior, NS; nasal inferior, NI; temporal superior, TS; and temporal inferior, TI) and two paracentral scores (PCSs; superior, PCSS; and inferior, PCSI). Cronbach alpha was always >0.90. The six scores decreased sequentially from IVF to DD to AD. Scores of AC were lower in NS, NI, and TS; PCSS was less in PCS; BSE scores were less in TS and TI; NaS scores were less in NS and NI. CONCLUSIONS: Six well-separated, optimal scores were obtained from the Humphrey perimetry matrix. Internal reliability was good. It was possible to discriminate between clinical subgroups. Further analyses, based on longitudinal data, must be performed to confirm these findings.

Cluster Analysis↗
PubMed2003

A description of how metal pollution occurs in the Tinto-Odiel rias (Huelva-Spain) through the application of cluster analysis.

In the last few decades, the study of space-time distribution and variations of heavy metals in estuaries has been extensively studied as an environmental indicator. In the case described here, the combination of acid water from mines, industrial effluents and sea water plays a determining role in the evolutionary process of the chemical makeup of the water in the estuary of the Tinto and Odiel Rivers, located in the southwest of the Iberian Peninsula. Based on the statistical treatment of the data from the analysis of the water samples from this system, which has been affected by processes of industrial and mining pollution, the 16 variables analyzed can be grouped into two large families. Each family presents high, positive Pearson r values that suggest common origins (fluvial or sea) for the pollutants present in the water analyzed and allow their subsequent contrast through cluster analysis.

Environmental Monitoring↗
PubMed2001

An improved optimization strategy and its application to clustering analysis.

In this paper, a new optimization strategy is put forward which locates as many potential unimodal regions as possible in the search space. The potential optima can be further explored by a global optimization method for searching in the identified unimodal regions. The proposed strategy was evaluated by the optimization of test functions. The results obtained by this approach are comparable with those achieved by variable step size generalized simulated annealing (VSGSA) and a genetic algorithm (GA). Finally, we used this strategy in a clustering analysis of a tobacco data set.

Algorithms↗
PubMed1992

Main structural and functional features of the basic cytosolic bovine 21 kDa protein delineated through hydrophobic cluster analysis and molecular modelling.

A 21 kDa protein purified from bovine brain cytosol was previously described as a hydrophobic ligand binding protein; however, its accurate biological function remained still uncertain. In order to get further information about its potential biological role, an extended prediction of its secondary and three dimensional structures was undertaken. We describe here a process which permitted us to discover a structural homology between the 21 kDa protein and the N-domain of yeast phosphoglycerate kinase (PGK). This process is based on comparing the 21 kDa protein with all the proteins presenting a slight homology, by using the Hydrophobic Cluster Analysis (HCA) method. According to the observed similarity between the N-domain of yeast PGK and the 21 kDa protein, we built a model which was shown to possess a potential binding site for nucleotides. Moreover, the model obtained presents three-dimensional (3D) structure similarity with adenylate kinase. These results suggest two main hypotheses: (i) the 21 kDa protein may belong to the kinase family; (ii) the binding of a nucleotide could imply a modification of the 3D structure of the 21 kDa protein that can promote the transfer of hydrophobic ligands to the plasma membrane. Meanwhile, verification of these hypotheses has been in part performed experimentally: the 21 kDa protein binds MgATP as well as, to a lesser extent, phosphoglycerate.

Amino Acid Sequence↗