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PubMed2004

From boys to men: predicting adult adaptation from middle childhood sociometric status.

This report examines the predictive validity of sociometric status at age 9-10 to young adult (age 23-24) antisocial behavior, work and school engagement, and arrests using Oregon Youth Study males (N = 206). A variety of analytic strategies included (a) multivariate analyses to examine the variation in adult adaptation as a function of sociometric classification at age 9-10, (b) regression analyses to evaluate the relative contribution of "liked most" and "liked least" peer nominations, and (c) structural equation modeling to predict the young adult outcome constructs from social preference at age 9-10. Contrary to expectation, when controlling for early antisocial behavior and academic skills, boys' social preference scores still predicted young adult outcomes. Longitudinal findings are discussed with respect to the salience of male peer rejection in middle childhood and the social developmental processes that may account for the predictive validity of peer rejection.

Adaptation, Psychological↗
PubMed2006

Vocal dysperiodicities estimation by means of adaptive long-term prediction.

An adaptive formulation of the long-term bidirectional linear predictive analysis is proposed in the context of the acoustic assessment of disordered speech. Vocal dysperiodicities are summarized by means of a signal-to-dysperiodicity ratio (SDR) marker. It is shown that performing an adaptive forward and backward long-term linear prediction of each speech sample and retaining the minimal prediction error energy as a cue of vocal dysperiodicity results in an SDR that correlates with the perceived degree of hoarseness. The coefficients of the time-varying long-term linear predictive model are estimated by means of the recursive least squares algorithm. The corpora comprise sustained vowels and French sentences produced by male and female normophonic and dysphonic speakers. A perceptual assessment of speech samples, which rests on comparative judgments, is used to evaluate the ability of the acoustic marker to predict subjective measures of voice quality. Experimental results show that the adaptive approach gives rise to high correlations for sustained vowels as well as for sentences.

Case-Control Studies↗
PubMed1993

Predicting skeletal adaptation in altered gravity environments.

It is generally agreed that the single factor that most limits human survivability in non-Earth environments is the phenomenon of bone demineralization and the medical problems induced by the subsequent imbalance in the calcium metabolism. Alterations of skeletal properties occur as a result of disturbances in the normal mechanical loading environment of bone. These alterations or "adaptations" obey physical laws, but the precise mathematical relationships remain to be determined. Principles governing unloading and overloading of bone are gaining more attention as a consequence of the planning of manned space stations, moon and Mars bases and spaceflights of long duration. This paper reviews the subject of bone remodeling and presents a mathematical framework which allows for the prediction of skeletal adaptation on Earth and in non-Earth gravity environments by power law relationships.

Adaptation, Physiological↗
PubMed2003

Plasma osmolality and the strong ion difference predict respiratory adaptations in pregnant and nonpregnant women.

This study tested the hypothesis that plasma osmolality and the strong ion difference ([SID]) predict PaCO2 during rest and during exercise in physically active pregnant (n = 22; gestational age 37.0 +/- 0.2 weeks) and nonpregnant (n = 17) women. Nonpregnant subjects were in varying stages of the menstrual cycle. Arterialized blood gases, hydrogen ion concentration, plasma osmolality, [SID], and circulating levels of progesterone were measured at rest and during upright cycling at work rates corresponding to 70 and 110% of the ventilatory threshold. Pooled data from the two groups at rest revealed significant correlations (P < 0.05) between PaCO2 with plasma osmolality, [SID], and progesterone. Progesterone was also significantly correlated with [SID] and osmolality. Also, changes in PaCO2 with exercise correlated significantly with changes in [SID]. The results support the hypothesis that plasma osmolality and [SID] are important factors in the modulation of respiratory sensitivity in healthy women. Also, the effects of progesterone on PaCO2 may be expressed, at least in part, through progesterone-induced changes in [SID] and osmolality.

Adult↗
PubMed1987

Appraisals of control and predictability in adapting to a chronic disease.

In a sample of 92 patients with rheumatoid arthritis, we examined interrelations among various control appraisals, illness predictability, psychosocial adjustment, mood, and illness status. Perceiving greater personal control over the disease and symptoms and perceiving greater health-care-provider control over symptoms were associated with greater illness predictability. Patients reported more personal control over their symptoms than over the course of the disease and thought that their health care providers had more control over disease course than they did themselves. Multiple regression analyses showed that perceiving greater personal control over one's medical care and treatment was associated with positive mood and psychosocial adjustment. Negative mood was also associated with the belief that providers have greater control over the patient's daily symptoms. Patients who had a more severe disease and expressed greater personal control over its course reported greater mood disturbance and were rated as exhibiting less positive adjustment, but those who had more severe daily symptoms and expressed greater personal control over their symptoms reported less mood disturbance. These findings are discussed in terms of the possible benefits of patients' active participation in their care and the implications of perceiving personal and others' control over more or less controllable aspects of the illness, especially when the illness is more severe.

Activities of Daily Living↗
PubMed2005

Structural adaptation increases predicted perfusion capacity after vessel obstruction in arteriolar arcade network of pig skeletal muscle.

Arteriolar arcades provide alternate pathways for blood flow after obstruction of arteries or arterioles such as occurs in stroke and coronary and peripheral vascular disease. When obstruction is prolonged, remaining vessels adjust their diameters chronically in response to altered hemodynamic and metabolic conditions. Here, the effectiveness of arcades in maintaining perfusion both immediately following obstruction and after structural adaptation was examined. Morphometric data from a vascular casting of the pig triceps brachii muscle and published data were used to develop a computational model for the hemodynamics and structural adaptation of the arcade network between two feed artery branches, FA1 and FA2. The predicted total flow to capillaries (Q(TA)) in the region initially supplied by FA2 decreased to 26% of the normal value immediately after FA2 obstruction but was restored to 78% of the normal value after adaptation. After obstruction of 1-10 randomly selected arcade segments, Q(TA) was on average 18% higher in the arcade network than in a corresponding two-tree network without arcades. Structural adaptation increased Q(TA) by an additional 16% in the arcade network but had almost no effect in the two-tree network. These results indicate that arcades can partially maintain blood flow after vascular blockage and that this effect is substantially enhanced by structural adaptation.

Acclimatization↗
PubMed1991

Prediction of responses in milk constituents to changes in the nutrition of dairy cows.

Milk quotas, based on an average fat content, severely limit milk production on UK farms. Predictions of the time-course of lactation are incorporated into most computerized herd management programs but these models take no account of food inputs, body weight change or milk composition. Dynamic models are generally used to simulate metabolic pathways and, as such, have little direct relevance to commercial milk production. Dynamic models can be converted to an adaptive-predictive model that partitions food energy into milk and non-milk constituents. This paper reports the development of an adaptive-predictive model to partition food into milk and non-milk components. Additional functions further partition milk energy into the principal constituents, fat, protein and lactose.

Animal Feed↗
PubMed2006

Ecotoxicity prediction by adaptive fuzzy partitioning: comparing descriptors computed on 2D and 3D structures.

Classification models were established on four endpoints, i.e. trout, daphnia, quail and bee, including from 100 to 300 pesticides subdivided into 3 toxicity classes. For each species, five separate sets of molecular descriptors, computed by several software, were compared, including parameters related to 2D or 3D structures. The most relevant descriptors were selected with help of a procedure based on genetic algorithms. Then, structure-activity relationships were built by Adaptive Fuzzy Partition (AFP), a recursive partitioning method derived from Fuzzy Logic concepts.Globally, satisfactory results were obtained for each animal species. The best cross-validation and test set scores reached values of about 70-75%. More important, the relationships derived from the descriptors calculated from 2D structures were superior or similar to those computed from 3D structures. These results underline that the long computational time employed to compute 3D descriptors is often useless to improve the prediction ability of the ecotoxicity models. Finally, the differences in the prediction ability between the different software used were quite reduced and show the possibility to use different descriptor packages for obtaining similar satisfactory models.

Animals↗
PubMedDate not supplied

Appraisal, social support, and life events: predicting outcome behavior in school-age children.

To examine the relation between social support and appraisal of life events in predicting adaptive, externalizing, and internalizing behavior in 265 school-age children, child-report on both a global and a significant other measure of social support was used. Life event scores were separated into events endorsed as negative and events endorsed as positive by the child. Using hierarchical regression analyses, the present study tested two models: main effects and moderator models of the relation between life events, social support, and behavioral outcome. Support was found for global social support and positive life events in predicting adaptive, externalizing, and internalizing behavior. Gender differences were also found. Support was found for both the main effects and moderator models of the association between life events and global social support. Appraisal of life events as positive appears to compensate for lower levels of global social support. Appraisal is discussed as a possible protective factor from maladjustment after exposure to major life events.

Adaptation, Psychological↗
PubMed2005

Experimental models of developmental programming: consequences of exposure to an energy rich diet during development.

Studies in both humans and experimental animals addressing the 'Fetal Origins of Adult Disease' hypothesis have established a relationship between an adverse intrauterine environment and offspring disease in adult life. This phenomenon, termed 'fetal programming' describes a process whereby a stimulus in utero establishes a permanent response in the fetus leading to enhanced susceptibility to later disease. However, the environment, during periods of developmental plasticity in postnatal life, can also 'programme' function. Thus, the terms 'developmental programming' and the 'Developmental Origins of Adult Health and Disease' are preferentially utilized. The 'Thrifty Phenotype' hypothesis explained the association between insufficient in utero nutrition and the later development of Type 2 diabetes. Most recently the 'Predictive Adaptive Response' hypothesis proposes that the degree of mismatch between the pre- and postnatal environments is an important determinant of subsequent disease. Epidemiological studies have indicated that fetal growth restriction correlates with later disease, implying that fetal nutritional deprivation is a strong programming stimulus. This prompted the development of experimental animal models using controlled maternal calorie, protein or macronutrient deficiency during key periods of gestation. However, in many societies, maternal and postnatal nutrition are either sufficient or excessive. Here, we examine findings from a range of nutritional studies examining maternal and/or postnatal nutritional excess. There is supportive evidence from a limited number of studies to test the 'Predictive Adaptive Response' hypothesis. These suggest that maternal over-nutrition is deleterious to the health of offspring and can result in a phenotype of the offspring that is characteristic of metabolic syndrome.

Adaptation, Physiological↗
PubMed2007

Sucrose feeding during pregnancy and lactation elicits distinct metabolic response in offspring of an inbred genetic model of metabolic syndrome.

The importance of early environment, including maternal diet during pregnancy, is suspected to play a major role in pathogenesis of metabolic syndrome and related conditions. One of the proposed mechanisms is a mismatch between the prenatal and postnatal environments, leading to misprogramming of the metabolic and signaling pathways of the developing fetus. We assessed whether the exposure to high-sucrose diet (HSD) alleviates the detrimental effects of sucrose feeding in later life (predictive adaptive hypothesis) in a highly inbred model of metabolic syndrome, the PD/Cub rat. Rat dams were continuously fed either standard or HSD (70% calories as sucrose) starting 1 wk before breeding, throughout pregnancy, at birth, and until weaning of the offspring. After weaning, all male offspring were fed HSD until the age of 20 wk, when detailed metabolic and morphometric profiles were ascertained. The early life exposure to a sucrose-rich diet resulted in distinct responses to longtime postnatal HSD feeding. Offspring of the sucrose-fed mothers displayed higher adiposity and substantial increases in triglyceride liver content together with unfavorable distribution of cholesterol into lipoprotein subfractions. On the other hand, their adiponectin concentrations were significantly higher, and insulin sensitivity of skeletal muscle was enhanced compared with the offspring of standard diet-fed mothers. Triglycerides, free fatty acids, overall glucose tolerance, and the insulin sensitivity of adipose tissue were comparable in both groups. In the genetically identical animals, maternal HSD feeding elicited a variety of subtle effects but did not lead to predictive adaptive protection from most HSD-induced metabolic derangements.

Animals↗
PubMed2000

Physiological models to understand exercise fatigue and the adaptations that predict or enhance athletic performance.

A popular concept in the exercise sciences holds that fatigue develops during exercise of moderate to high intensity, when the capacity of the cardiorespiratory system to provide oxygen to the exercising muscles falls behind their demand inducing "anaerobic" metabolism. But this cardiovascular/anaerobic model is unsatisfactory because (i) a more rigorous analysis indicates that the first organ to be affected by anaerobiosis during maximal exercise would likely be the heart, not the skeletal muscles. This probability was fully appreciated by the pioneering exercise physiologists, A. V Hill, A. Bock and D. B. Dill, but has been systematically ignored by modern exercise physiologists; (ii) no study has yet definitely established the presence of either anaerobiosis, hypoxia or ischaemia in skeletal muscle during maximal exercise; (iii) the model is unable to explain why exercise terminates in a variety of conditions including prolonged exercise, exercise in the heat and at altitude, and in those with chronic diseases of the heart and lungs, without any evidence for skeletal muscle anaerobiosis, hypoxia or ischaemia, and before there is full activation of the total skeletal muscle mass, and (iv) cardiovascular and other measures believed to relate to skeletal muscle anaerobiosis, including the maximum oxygen consumption (VO2 max) and the "anaerobic threshold", are indifferent predictors of exercise capacity in athletes with similar abilities. This review considers four additional models that need to be considered when factors limiting either short duration, maximal or prolonged submaximal exercise are evaluated. These additional models are: (i) the energy supply/energy depletion model; (ii) the muscle power/muscle recruitment model; (iii) the biomechanical model and (iv) the psychological model. By reviewing features of these models, this review provides a broad overview of the physiological, metabolic and biomechanical factors that may limit exercise performance under different exercise conditions. A more complete understanding of fatigue during exercise, and the relevance of the adaptations that develop with training, requires that the potential relevance of each model to fatigue under different conditions of exercise must be considered.

Adaptation, Physiological↗
PubMed1991

Automatic tracking and digitization of multiple radiopaque myocardial markers.

An 80386 PC-based system was designed to track automatically multiple, miniature radiopaque markers implanted in the heart wall. This system eliminated the need for tedious, time-consuming manual digitization of marker coordinates. Use of a MATROX MVP-AT/NP image processing board incorporated advanced image processing and graphics features into the low-cost PC environment. Digital image enhancement and segmentation techniques (such as limiting analysis to predefined windows of interest, spatial band-pass and matched filtering, contrast stretching and clipping, linear adaptive prediction, intensity histogram analysis, adaptive binary thresholding, region growing, expanding region of analysis, and feature extraction) were incorporated into a user-friendly integrated marker processing software environment. Improved speed, accuracy, and reproducibility of the marker digitizing process were realized. These basic techniques have broad applications to other image processing needs in biomedical research.

Algorithms↗
PubMed1980

Devolution of inhomogeneities in bone structure--predictions of adaptive elasticity theory.

In this paper we consider an initially inhomogeneous adaptive elastic body subjected to a steady homogeneous stress state. The adaptive elastic body, which is a model for living bone tissue, is inhomogeneous in both its anisotropic elastic properties and its density. The principal result of the paper is the determination of the devolution of the initially inhomogeneous body to a homogeneous body under the influence of the steady homogeneous stress state. A cylindrical body that is inhomogeneous along the axis of the cylinder, but homogeneous in each transverse plane of the cylinder, is used as an example. This cylindrical body is loaded by a steady uniform stress directed along the cylindrical axis. The temporal devolution of an inhomogeneity in the initial shape of a sine wave is illustrated. As time progresses the amplitude of the sine wave decreases, rapidly at first and then more slowly. As time becomes very large the sine wave becomes a straight line signifying that the cylinder has become homogeneous.

Biomechanical Phenomena↗
PubMed2004

Learning to predict through adaptation.

Common themes underlying three recent studies of mine on disparate topics are reviewed: the lamination of sensory cortex; the differentiation into subfields of the mammalian hippocampus; and the neuronal dynamics that might underlie the faculty for language in the human frontal lobes. These studies all discuss the evolution of cortical networks in terms of their computations, quantified by simulating simplified formal models. They all dwell on the interrelationship between qualitative and quantitative change. Finally, they all include, as a necessary ingredient of the relevant computational mechanism, a simple feature of pyramidal cell biophysics: firing rate adaptation.

Adaptation, Psychological↗