Dyson-Schwinger loop equations of the two-matrix model: Correlations in quantum chaos.
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Journal Article↗
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Out-patient rehabilitation improves activities of daily living, quality of life and exercise tolerance in chronic obstructive pulmonary disease.
The purpose of this study was to investigate the effects on activities of daily living, quality of life, and exercise tolerance of a comprehensive out-patient rehabilitation programme for patients with moderate-to-severe chronic obstructive pulmonary disease. In this randomized and controlled trial, the main outcome measures were Activities of Daily Living (ADL) score, York Quality of Life Questionnaire (YQLQ) score, Chronic Respiratory Disease Questionnaire (CRDQ) score, 6 min walking distance (6MWD), forced expiratory volume in one second (FEV1), and forced vital capacity (FVC). The rehabilitation programme included physical training, occupational therapy, education, and smoking cessation therapy, and lasted for 12 weeks. The patients were evaluated at entry, halfway through, and at the end of the programme. Follow-up was at 24 weeks. Forty seven patients were recruited, and 16 in each group completed the trial. There were significant differences in the improvements in ADL and CRDQ between the control and the treatment groups at 12 and 24 weeks, and at 24 weeks, respectively. At 6, 12 and 24 weeks, improvements in the 6MWD were 21.6 versus 79.8, 36.1 versus 113.1 and 21.4 versus 96.2 for control and treatment groups, respectively (p<0.004). A correlation matrix showed only ADL and 6MWD to be significantly correlated; the matrix was also used to validate the translated questionnaires. The programme required 124 staff-hours in total. An inexpensive, comprehensive out-patient rehabilitation programme can produce long-term improvement in activities of daily living, quality of life, and exercise tolerance in patients with moderate-to-severe chronic obstructive pulmonary disease.
Activities of Daily Living↗
Interactional structures of therapist and client participation in adult psychotherapy: P technique and chronography.
In previous studies, the utterances of 6 clients and their therapists in early, middle, and late sessions were rated on 34 and 39 speech categories, respectively. P-technique analyses revealed 4 client and 4 therapist factors. For the present study, therapist and client utterances were assigned factor scores. A 17 x 17 correlation matrix was constructed, consisting of correlations across 4 lagged utterances (therapist-client-therapist-client), with each utterance represented by 4 factor scores and a score for the third from which the utterance was sampled. Principal-components analysis of this matrix revealed 4 therapist-client interaction factors: Mutual Therapeutic Engagement, Therapeutic Negotiation, Undirected Client Reminiscence, and Sustained Therapist Work. Unsuccessful cases deviated most from successful cases on at least 1 factor. Comparisons of interaction chronographs of episodes drawn from a successful and unsuccessful case revealed meaningful differences. Discussion highlights the power of P technique to reveal structures of psychotherapeutic discourse.
Adult↗
Optimizing PCA methodology for ERP component identification and measurement: theoretical rationale and empirical evaluation.
OBJECTIVE: To determine how specific methodological choices affect "data-driven" simplifications of event-related potentials (ERPs) using principal components analysis (PCA). The usefulness of the extracted component measures can be evaluated by knowledge about the variance distribution of ERPs, which are characterized by the removal of baseline activity. The variance should be small before and at stimulus onset (across and within cases), but large near the end of the recording epoch and at ERP component peaks. These characteristics are preserved with a covariance matrix, but lost with a correlation matrix, which assigns equal weights to each sample point, yielding the possibility that small but systematic variations may form a factor. METHODS: Varimax-rotated PCAs were performed on simulated and real ERPs, systematically varying extraction criteria (number of factors) and method (correlation/covariance matrix, using unstandardized/standardized loadings before rotation). RESULTS: Conservative extraction criteria changed the morphology of some components considerably, which had severe implications for inferential statistics. Solutions converged and stabilized with more liberal criteria. Interpretability (more distinctive component waveforms with narrow and unambiguous loading peaks) and statistical conclusions (greater effect stability across extraction criteria) were best for unstandardized covariance-based solutions. In contrast, all standardized covariance- and correlation-based solutions included "high-variance" factors during the baseline, confirming findings for simulated data. CONCLUSIONS: Unrestricted, unstandardized covariance-based PCA solutions optimize ERP component identification and measurement.
Adult↗
The effect of branched-chain amino acid-enriched parenteral nutrition on gut permeability.
In situations of catabolic stress, the gut becomes atrophic and has a diminished barrier function as evidenced by an increased permeability to a variety of molecules. It is known that the parenteral administration of branched-chain amino acids (BCAA) reduce gut atrophy. The aim of this study was to examine the effect of BCAA-enriched solutions of parenteral nutrients on gut permeability. A secondary aim was to observe the association between gut permeability and variables that have been used to assess jejunal atrophy. Central venous lines were inserted into 30 rats before randomization to receive nutritional support with: (1) a conventional parenteral solution (CPN), (2) A 2.0% BCAA-enriched solution (BCAA), or (3) rat food ad lib (Rat Food). The rats were assessed after 7 d for nutritional status, gut morphology, and gut permeability ratio (ratio of the permeability to 14C raffinose and 3H mannitol). We found that rats in the Rat Food Group lost the least amount of weight, had the least amount of jejunal atrophy, and had better preservation of barrier function as determined by gut permeability. When compared with the CPN Group, the BCAA Group had better preservation of jejunal morphology and protein content (p < 0.05), but a similar gut permeability. A cross-correlation matrix demonstrated a significant negative correlation between permeability to mannitol and mucosal weight, mucosal protein content and mucosal DNA content. Branched-chain amino acid-enriched parenteral nutrition reduced gut atrophy but not the gut permeability associated with parenteral nutrition. In the parenterally nourished rat model, atrophy of the jejunum is associated with increased permeability to small molecules.
Amino Acids, Branched-Chain↗
Model for correlations in stock markets
We propose a group model for correlations in stock markets. In the group model the markets are composed of several groups, within which the stock price fluctuations are correlated. The spectral properties of empirical correlation matrices reported recently are well understood from the model. It provides the connection between the spectral properties of the empirical correlation matrix and the structure of correlations in stock markets.
Journal Article↗
Learning lateral interactions for feature binding and sensory segmentation from prototypic basis interactions.
We present a hybrid learning method bridging the fields of recurrent neural networks, unsupervised Hebbian learning, vector quantization, and supervised learning to implement a sophisticated image and feature segmentation architecture. This architecture is based on the competitive layer model (CLM), a dynamic feature binding model, which is applicable on a wide range of perceptual grouping and segmentation problems. A predefined target segmentation can be achieved as attractor states of this linear threshold recurrent network, if the lateral weights are chosen by Hebbian learning. The weight matrix is given by the correlation matrix of special pattern vectors with a structure dependent on the target labeling. Generalization is achieved by applying vector quantization on pair-wise feature relations, like proximity and similarity, defined by external knowledge. We show the successful application of the method to a number of artifical test examples and a medical image segmentation problem of fluorescence microscope cell images.
Image Processing, Computer-Assisted↗
Profiles of serum complement in patients with hepatobiliary diseases.
CH50 and the concentrations of C3, C4, C1 INH and factor B have been measured in sera from 34 control subjects and 178 patients with various hepatobiliary diseases, including primary biliary cirrhosis (PBC), chronic active hepatitis (CAH), cryptogenic cirrhosis (CC), alcoholic liver disease (ALD), Wilson's disease (WD), large duct biliary obstruction (LDBO) and viral hepatitis (VH). CH50 was decreased in CAH and CC. C3 was increased in PBC, LDBO and VH and decreased in CAH and CC. C4 was decreased in PBC, CAH, ALD and WD. C1 INH was increased in PBC, CAH, ALD, LDBO and VH. Factor B was increased in LDBO and VH and decreased in CC. In none of the patient groups was the mean C4 level increased or the mean C1 INH level decreased. All 5 indices of serum complement were lower in ascitic than nonascitic patients. Data on serum complement were similar in HBsAg positive and negative VH. Discriminant analysis facilitated separation of all the patient groups on the basis of complement data, except PBC and VA. Analysis of data using a within-group correlation matrix revealed a significant negative correlation between C4, the most discriminating variable of serum complement in CAH, and gamma-globulin concentration in CAH. The possible contribution of factors such as activation of complement, impaired hepatic synthesis of complement components, an acute phase response and cholestasis to altered serum complement profiles in different hepatobiliary diseases is discussed.
Adolescent↗
[Physiological mechanisms of prevention of occupational hypoacusis].
This study and mathematical analysis by constructing a correlation matrix, a diagram of significant correlations, a multiple regression model of 77 indices of the body's main systems in 91 drift miners and drillers who had a service length of 7-27 years showed the physiological mechanisms of auditory function system and revealed 3 basic levels of energy metabolism regulation: 1) neuroreflectory (cortical mechanisms) and autonomic (sympathetic) adaptive-and-homeostatic regulation; 2) neurohumoral and metabolic adaptive-compensatory ergotropic self-regulation of blood circulation and respiration; 3) parasympathetic neuroreflectory and metabolic compensatory trophotropic regulation of respiration and blood circulation. The established regularities were used as a basis in developing methods and criteria for individual sensitivity to noise, criteria for specific adaptation during labour activity.
Adaptation, Physiological↗
Relationship of remote sensing normalized differential vegetation index to Anopheles density and malaria incidence rate.
OBJECTIVE: To study the relationship of remote sensing normalized differential vegetation index (NDVI) to Anopheles density and malaria incidence rate. METHODS: Data of monthly average climate, environment, Anopheles density and malaria incidence rate, and remote sensing NDVI were collected from 27 townships of 10 counties in southeastern Yunnan Province from 1984 to 1993. The relationship of remote sensing ecological proxy index, NDVI, to Anopheles density and malaria incidence rate was studied by principal component analysis, factor analysis and grey correlation analysis. RESULTS: The correlation matrix showed that NDVI highly correlated with Anopheles density in 4 townships of Mengla, Jinghong, and Yuanjiang counties, but in other 23 townships the relationship was not clear. Principal component and factor analyses showed that remote sensing NDVI was the representative index of the first principal component and the first common factor of Anopheles density evaluation. Grey correlation analysis showed that in rainy season NDVI had a high grey correlation with Anopheles density and malaria incidence rate. The grey correlation analysis showed that in rainy season the grey degree of NDVI correlated with Anopheles. Minimus density was 0.730, and 0.713 with Anopheles sinensis density, and 0.800 with malarial incidence rate. CONCLUSION: Remote sensing NDVI can serve as a sensitive evaluation index of Anopheles density and malaria incidence rate.
Animals↗
Direct estimation and inference of higher-level correlations from lower-level measurements with applications in gene-pathway and proteomics studies.
This paper tackles the challenge of estimating correlations between higher-level biological variables (e.g. proteins and gene pathways) when only lower-level measurements are directly observed (e.g. peptides and individual genes). Existing methods typically aggregate lower-level data into higher-level variables and then estimate correlations based on the aggregated data. However, different data aggregation methods can yield varying correlation estimates as they target different higher-level quantities. Our solution is a latent factor model that directly estimates these higher-level correlations from lower-level data without the need for data aggregation. We further introduce a shrinkage estimator to ensure the positive definiteness and improve the accuracy of the estimated correlation matrix. Furthermore, we establish the asymptotic normality of our estimator, enabling efficient computation of P-values for the identification of significant correlations. The effectiveness of our approach is demonstrated through comprehensive simulations and the analysis of proteomics and gene expression datasets. We develop the R package highcor for implementing our method.
Proteomics↗
Assessment of anthropometric, systemic, and lifestyle factors influencing bone status in the legs of spinal cord injured individuals.
The aim of the present study was to assess the influence of muscle spasms, systemic or lifestyle factors on bone mass and geometry of the femur and the tibia in people with long-standing spinal cord injury (SCI). Fifty-four motor complete SCI people with paralysis duration of between 5 and 50 years were included in the study. Spasticity was measured by means of the Ashworth scale. Distal epiphyses and mid shafts of the femur, tibia, and radius were measured by peripheral quantitative computed tomography. From the epiphyseal scans, trabecular and total bone mineral density (BMDtrab and BMDtot) were calculated, and from the shaft scans, cortical BMD (BMDcort), total and cortical cross-sectional area (CSAtot and CSAcort), and muscle cross-sectional areas (CSAmus) were determined. Personal characteristics, anthropometric, as well as life-style factors, were assessed by means of a questionnaire. A Spearman correlation matrix was produced with measured data. Correlation coefficients exceeding 0.3 were tested for significance by performing linear regression for parametric data and ANOVA for non-parametric data. Subjects with higher spasticity scores had significantly larger CSAmus in the upper and lower leg. Both spasticity and CSAmus were found to be significantly related to BMDtrab and BMDtot of the distal epiphysis of the femur and to CSAcort of the femoral shaft. In the lower leg, bone parameters of the tibia were found to be strongly related to corresponding bone parameters of the radius, which suggests a systemic origin. No significant relationships were found between bone parameters and any of the life-style factors. The extent of bone loss caused by disuse of the lower extremities in people with long-standing SCI is influenced by systemic factors. Additionally, spasticity has a positive effect on bone parameters of the femur.
Adult↗
Characterization of the human salivary basic proline-rich protein complex by a proteomic approach.
Thirteen samples of human normal whole saliva were analyzed by RP-HPLC-ESI-MS and MALDI-TOF-MS to investigate the basic proline-rich protein complex. Between known basic-PRPs the P-B, P-C (or IB-8b), P-D (or IB-5), P-E (or IB-9), P-F (or IB-8c), P-H (or IB-4), IB-6, II-2, IB-1, and IB-8a glucosylated were identified, whereas the II-1, IB-7, PA, and D1-A peptides were not detected. Some detected masses not attributable to known basic-PRPs were putatively ascribed to II-2 and IB-1 nonphosphorylated, II-2 and IB-1 missing the C-terminal arginine residue, and the 1-62 fragment of IB-6, named P-J peptide. A correlation matrix analysis revealed a cluster of correlation among all the basic PRPs (apart from the P-B peptide) which is in agreement with their common parotid origin.
Chromatography, High Pressure Liquid↗
Relationship and comparison of selected anthropometric measures to muscular endurance and strength in children aged 3-5 years.
This study investigated the relationships and differences between grip strength, hang time (upper body muscular endurance), sum of skinfold measures, body weight and height among 103 children 3-5 years of age. The results indicated that the only significant (P less than 0.05) difference between groups on skinfold was at the umbilical site, where the 3-year-old's measurements were larger than the 4- or 5-year-old group. All strength and body weight measures increased with age and in each case were significantly (P less than 0.01) different between groups. Analysis of the correlation matrix representing key variables revealed no correlations which could be regarded as high practical indicators; thus it was concluded that body weight, height, and selected skinfold measurements were not practical indicators of grip strength and muscular endurance.
Aging↗
Pulmonary function of different categories of chronic obstructive pulmonary diseases in railway workers of eastern India.
Pulmonary function tests were done on 146 established chronic obstructive pulmonary disease (COPD) patients and 151 normal non-smoker and smoker subjects. These patients were assembled from Garden Reach Railway Hospital (Calcutta), West Bengal, India, 79 of which suffered from chronic bronchitis, 8 from chronic bronchitis with mild emphysema (who were included in the chronic bronchitis group), 38 from emphysema and 21 from asthma. In the normal subjects 75 were non-smokers and 76 smokers. All the subjects were in the age range of 16-60 years. The mean values obtained in COPD patients were compared with those of normal non-smokers and smokers in each group and amongst the different categories of COPD patients. All the pulmonary function tests (PFT) were measured by the standard spirometric technique, and the Peak Expiratory Flow Rate (PEFR) was studied by Wright's Peak Flow Meter. The values were expressed in body temperature at ambient pressure saturated with Water Vapour Pressure (BTPS). The PFT values significantly deteriorated in all categories of COPD patients as compared to normal non-smokers and smokers, but a few parameters showed exceptions. Significant deterioration was observed in emphysematous patients when compared to other categories of COPD patients. No definite trend of reduction of pulmonary function test values were found according to the years of suffering from the disease. A product moment correlation matrix showed a highly significant positive correlation between FVC and FEV1, in all four groups of patients. These two parameters also showed a strong positive relationship with FEF25-75%, FEF200-1200ml, FEF75-85%, MVVF and PEFR. The regression equations for some of the closely related variables of high correlation coefficient were calculated in COPD patients and presented.
Adolescent↗
[Analysis of ordinal repeated measures data using generalized estimating equation].
OBJECTIVE: To explore the application of the generalized estimating equation in the ordinal repeated measures data and hence provide methodology reference for the analysis of repeated measures data in the clinical trials. METHODS: An example was illustrated by modeling generalized estimating equation using the GENMOD command in comparison with the independent logistic regression. RESULTS: All parameters and their standard error were estimated, so every factor could be dealt with intuitive estimation of parameter. The standard errors of coefficients in generalized estimating equation are generally greater than that in independent logistic regression. CONCLUSION: Generalized estimating equation can solve the correlation between the dependent data by using working correlation matrix, and it can control strata correlation, repeated measures factor and other confounding factors effectively, so generalized estimating equation provides an effective method for the ordinal repeated measures data.
Clinical Trials as Topic↗
[Evaluation of lung scintigraphy using N-isopropyl-p-[123I]-iodoamphetamine].
N-isopropyl-p-[123I]-iodoamphetamine (123I-IMP) was examined for its relevancy as a labeling medium of lung scintigraphy in 30 patients with lung diseases and 20 healthy subjects. Lung diseases were classified into carcinoma and diffuse lung disease, and the all subjects with normal lung were classified into smokers and nonsmokers. To assess the reduction curve of 123I-IMP, mean transit time was calculated. Forced spirography was performed and spirographic values were analyzed. Spirographic parameters examined were vital capacity percent (%VC), forced expiratory volume in 1 sec divided by forced vital capacity (%) (FEV1.0%), and blood gas data. In the correlation matrix, the mean transit time was correlated with blood gas data, and not with %VC or FEV1.0%. In patients with lung diseases, the mean transit time was significantly prolonged; however, the difference was not significant between groups of carcinoma and benign disease, and between groups of smokers and nonsmokers. Wash-out images were obtained by the subtraction technique using the first frame image and 100-min delayed image. In patients with lung carcinoma, 87.5% of the tumors were depicted on wash-out images. The lesions were also depicted well in benign lung diseases. But among findings of wash-out image by 123I-IMP, air trapping image by 133Xe study and XCT study, there are some discordances to be clarified.
Adult↗
[The prognostic value of serochemical cholestasis parameters in liver cirrhosis].
In a semiprospective study on the prognosis of liver cirrhosis we investigated whether common, selected cholestasis parameters in liver diagnostics are associated with the survival time and the probability of survival and whether they permit prognostic statements. In 93 patients with liver cirrhosis of different aetiology the serum-bilirubin, gamma-GT, AP and AAP were determined for this purpose and applied in the same way as a clinically proven icterus to the survival time of the patients. The mean time of observation was 13.8 years (+/- 1.9 years). In the simple correlation matrix none of the cholestasis parameters correlated with the survival time. There was no difference in the frequency with which deceased and surviving patients suffered from icterus and, with the exception of AAP, there was no different serum concentration of the cholestasis parameters according to univariate analysis. However, icterus in the early phase of the observation time and increased gamma-GT (over 3000 nmol/l.s) in the late phase of observation were associated with a reduced probability of survival. Correspondingly, the serum-bilirubin of deceased patients (only slightly) correlated in the simple linear regression with their survival time. In multivariate analysis gamma-GT proved to be non-redundant for the estimation of the patients' probability of survival.
Adult↗