Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “predictability of adaptation”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

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

At least 1,567 records · Page 87Linked to original sources
PubMed1996

The Development of Measures of Individual Differences in Self-Regulatory Control and Their Relationship to Academic Performance

Two studies are reported describing the development and validation of the Strategic Flexibility Questionnaire (SFQ): a self-report instrument aimed at eliciting students' beliefs about the need for, and conditional nature of, self-regulatory control over learning. In Study 1, 281 first-year university education students completed a 40-item pilot questionnaire. Factor analysis of responses revealed a 21-item instrument indicating three types of control beliefs: adaptive executive control, inflexible executive control, and irresolute executive control. In Study 2, the predictive validity of these conceptions was tested against the academic performance of 105 third-year university education students. Results indicated that students reporting adaptive executive control beliefs were more successful academically, while those students reporting inflexible or irresolute control beliefs were significantly less successful academically.

Journal Article↗
PubMed1989

The social environment and the adaptation of mothers of physically handicapped children.

Evaluated relationships between social environmental characteristics and adaptation in 50 mothers of congenitally physically handicapped 6- to 11-year-old children. Mothers reported on utilitarian resources, child adjustment, psychosocial family resources, service utilization, and three dimensions of adaptation. Analyses of the concurrent correlational design indicated significant proportions of the variance in mental and social functioning were explained by features of the social environment. Mother's physical health could not be significantly predicted. Consistently strong contributions were made by psychosocial family resources in all adaptation domains.

Adaptation, Psychological↗
PubMed1995

Health promotion and exercise training.

Health is determined not only by the absence of disease, but also by an individual's resistance to pathogenic factors. In turn, resistance depends on the effectiveness of specific homeostatic regulation and the mechanism of general adaptation. Through the change in adaptivity, health may be increased or reduced. While it is difficult to predict which specific homeostatic mechanism will be necessary in various stages of life in the individual, it is more reliable to try to improve health, thereby increasing the effectiveness of the mechanism of general adaptation. Physical training results in a variety of changes in individuals. There are several changes which are essential both for increased exercise performance and for increasing adaptivity, by favouring the effectiveness of the mechanism of general adaptation. These changes: improve central nervous regulation and central nervous system functions; increase endocrine system capacity; increase energy potential; improve the capacity of the oxygen transport system; improve oxidation processes; increase metabolic and functional economy; increase functional stability; and increase the number of Na+,K+ -pumps. The influence of these changes on adaptivity is accomplished by the influence of exercise training on immunoactivities, and by the antisclerotic effect of training. The latter may be considered to be metabolic (actualised through the training effect on lipoprotein metabolism and aging-related calcium distribution) or mechanical (protection of tissues from sclerotic changes by their activities) effects. The training effects are specifically dependent upon performed exercises. Endurance exercise is considered to be the most important and widely recommended form of exercise for health improvement. Most of the training benefits (listed above) for increased adaptivity are induced by aerobic endurance training. Gymnastic exercises are indispensable in regard to mechanical antisclerotic effect. They are also essential influences on the central nervous system. Aerobic dance or aerobic rhythmic gymnastics are ways by which the positive effects of endurance and gymnastic exercise can be combined.

Adaptation, Physiological↗
PubMed2006

Sensory integration does not lead to sensory calibration.

One generally has the impression that one feels one's hand at the same location as one sees it. However, because our brain deals with possibly conflicting visual and proprioceptive information about hand position by combining it into an optimal estimate of the hand's location, mutual calibration is not necessary to achieve such a coherent percept. Does sensory integration nevertheless entail sensory calibration? We asked subjects to move their hand between visual targets. Blocks of trials without any visual feedback about their hand's position were alternated with blocks with veridical visual feedback. Whenever vision was removed, individual subjects' hands slowly drifted toward the same position to which they had drifted on previous blocks without visual feedback. The time course of the observed drift depended in a predictable manner (assuming optimal sensory combination) on the variable errors in the blocks with and without visual feedback. We conclude that the optimal use of unaligned sensory information, rather than changes within either of the senses or an accumulation of execution errors, is the cause of the frequently observed movement drift. The conclusion that seeing one's hand does not lead to an alignment between vision and proprioception has important consequences for the interpretation of previous work on visuomotor adaptation.

Adaptation, Physiological↗
PubMed1980

Vector model for normal and dichromatic color vision.

The inclusion of cone mechanisms in a slightly revised version of an earlier model allows accounts of phenomena that involve receptor effects as well as dichromatic color vision. Intensity-dependent parameters that stimulate the adaptation of receptors and opponent and nonopponent mechanisms are varied to predict a wide range of data for both normals and dichromats, including: (i) color matching; (ii) the approximate apparent hue and saturation of the spectrum; (iii) foveal spectral sensitivities obtained by flicker photometry and by detection in the dark and under conditions of achromatic or chromatic adaptation; (iv) heterochromatic additivity failures in the dark-adapted and chromatically adapted eye; (v) approximate differences between brightness and luminance; and, (vi) color and wavelength discrimination under varying adaptation conditions.

Color↗
PubMed1978

Voluntary movement control and adaptation to cross-coupled stimulation.

The rates at which protective adaptation was acquired to an incremental cross-coupled stimulus were compared under three conditions of movement control: 1) a passive condition in which the 45 degree lateral tilts of the subject's chair were controlled entirely by the experimenter (N = 12); 2) an active condition in which the same movements were achieved directly through the subject's own muscular effort (N = 12); and 3) an active-passive condition in which control was exercised indirectly through microswitches located on the chair arms (N = 12). Adaptation was measured by the rate of neutralization of the oculogyral illusion, as estimated from the apparent motion of a small, dimly illuminated target. The results supported the prediction that the passive condition would be the least effective mode for acquiring adaptation. An unexpected finding was that the active-passive condition proved to be the most efficient for the development of adaptation.

Adaptation, Physiological↗
PubMed2002

DrugScore meets CoMFA: adaptation of fields for molecular comparison (AFMoC) or how to tailor knowledge-based pair-potentials to a particular protein.

The development of a new tailor-made scoring function to predict binding affinities of protein-ligand complexes is described. Knowledge-based pair-potentials are specifically adapted to a particular protein by considering additional ligand-based information. The formalism applied to derive the new function is similar to the well-known CoMFA approach, however, the fields used in the approach originate from the protein environment (and not from the aligned ligands as in CoMFA, thus, a "reverse" CoMFA (= AFMoC) named Adaptation of Fields for Molecular Comparison is performed). A regular-spaced grid is placed into the binding site and knowledge-based pair-potentials between protein atoms and ligand atom probes are mapped onto the grid intersections resulting in "potential fields". By multiplying distance-dependent atom-type properties of actual ligands docked into the binding site with the neighboring grid values, "interaction fields" are produced from the original "potential fields". In a PLS analysis, these atom-type specific interaction fields are correlated to the actual binding affinities of the embedded ligands, resulting in individual weighting factors for each field value. As in CoMFA, the results of the analysis can be interpreted in graphical terms by contribution maps, and binding affinities of novel ligands are predicted by applying the derived 3D QSAR equation. The scope of the new method is demonstrated using thermolysin and glycogen phosphorylase b as test examples. Impressive improvements of the predictive power for affinity prediction can be achieved compared to the application of the original knowledge-based potentials by considering a sample set of only 15 known training ligands. Thus, with growing information about the drug target studied, the new method allows one to move gradually from generally valid to protein-specifically adapted pair-potentials, depending on the amount of training information available and its degree of structural diversity. In addition, convincing predictive power is also achieved for ligand poses generated by automatic docking tools.

Databases, Factual↗
PubMed2006

Chronotropic incompetence in young patients with late postoperative atrial flutter: a case-control study.

AIMS: Atrial flutter causes late postoperative morbidity in congenital heart disease (CHD). Sinoatrial node dysfunction is associated with late postoperative atrial flutter, but pacing interventions driven by minimum heart rates (HR) have yielded mixed results. METHODS AND RESULTS: A retrospective case-control study was used to test the hypothesis that late postoperative atrial flutter is associated with chronotropic incompetence in active young CHD patients. Control CHD patients aged < or =18 years without documented supraventricular ectopy (n = 42) were matched with 42 patients (cases) having atrial flutter onset > or =6 months postoperatively. Minimum, average, and maximum non-flutter HRs were obtained from outpatient ambulatory 24 h ECG (Holter) recordings and graded exercise tests. Chronotropic competence was assessed using percentage of age-specific predicted maximum HR achieved, and calculated chronotropic index. Effects of rate-adaptive programming and maximum atrial pacing rates were analysed in 19 permanently paced cases. Least square estimates of minimum HRs were similar in cases and controls (54+/-2 vs. 52+/-2 bpm). Average HRs were lower in cases (75+/-2 vs. 81+/-2 bpm, P=0.02). Cases and controls differed most significantly with respect to percentage of predicted maximum HR achieved (67+/-2 vs. 80+/-2%, P < 0.001). This difference remained highly significant when the data were adjusted for age, sex, permanent pacing, and negatively chronotropic medication usage at the time of testing. Among paced patients, atrial flutter was significantly less likely to be observed in the setting of rate-adaptive pacing [odds ratio (OR) = 0.36; P < 0.05], and the likelihood of detecting atrial flutter decreased relative to the maximum programmed atrial pacing rate (OR 0.87 for every 5% increment in maximum pacing rate relative to maximum predicted HR for age; P < 0.05). CONCLUSION: Late postoperative atrial flutter is associated with chronotropic incompetence in paediatric CHD patients.

Adolescent↗
PubMedDate not supplied

Role of the MTT chemosensitivity test in the prognosis of gastric cancer patients after postoperative adjuvant chemotherapy.

The clinical usefulness of the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) chemosensitivity test (MTT assay; MTTA) in the selection of anticancer drugs against advanced gastric cancer (AGC) was evaluated. MTTA is widely used to predict patient responses to particular drugs, allowing for the selection of appropriate chemotherapeutic drugs and the avoidance of ineffective chemotherapeutic drugs, thereby improving patient survival. Since 1989, we have accumulated MTTA efficacy data from AGC patients. In this study, the present clinical roles of MTTA and the data from 202 patients with stage III or IV gastric cancer analyzed for survival outcome following surgery, with or without postoperative chemotherapy, evaluated by MTTA, are discussed. The patients were divided into 3 groups; an adapted group found to be sensitive to chemotherapy by MTTA, a non-adapted group found to be insensitive to chemotherapy by MTTA and a group that received no chemotherapy. For stage III gastric cancer patients, the adapted group had a statistically better survival rate compared to the other groups, while for stage IV patients, there was no difference in survival rate between any of the groups. However, further classification of stage IV patients as to the presence or absence of peritoneal dissemination (P) showed that the adapted group with P showed better prognoses than the other groups with P. The analysis of data collected since 2000 revealed that the 11 patients in the taxane-adapted group, who received chemotherapeutic regimens that included taxanes and were found to be sensitive to taxanes by MTTA, demonstrated better survival than the taxane non-adapted group (n=11) (p=0.045). In conclusion, MTTA results predicted patient prognoses, based on the selection of appropriate chemotherapy.

Adult↗
PubMed2004

Adaptive meshing technique applied to an orthopaedic finite element contact problem.

Finite element methods have been applied extensively and with much success in the analysis of orthopaedic implants. Recently a growing interest has developed, in the orthopaedic biomechanics community, in how numerical models can be constructed for the optimal solution of problems in contact mechanics. New developments in this area are of paramount importance in the design of improved implants for orthopaedic surgery. Finite element and other computational techniques are widely applied in the analysis and design of hip and knee implants, with additional joints (ankle, shoulder, wrist) attracting increased attention. The objective of this investigation was to develop a simplified adaptive meshing scheme to facilitate the finite element analysis of a dual-curvature total wrist implant. Using currently available software, the analyst has great flexibility in mesh generation, but must prescribe element sizes and refinement schemes throughout the domain of interest. Unfortunately, it is often difficult to predict in advance a mesh spacing that will give acceptable results. Adaptive finite-element mesh capabilities operate to continuously refine the mesh to improve accuracy where it is required, with minimal intervention by the analyst. Such mesh adaptation generally means that in certain areas of the analysis domain, the size of the elements is decreased (or increased) and/or the order of the elements may be increased (or decreased). In concept, mesh adaptation is very appealing. Although there have been several previous applications of adaptive meshing for in-house FE codes, we have coupled an adaptive mesh formulation with the pre-existing commercial programs PATRAN (MacNeal-Schwendler Corp., USA) and ABAQUS (Hibbit Karlson and Sorensen, Pawtucket, RI). In doing so, we have retained several attributes of the commercial software, which are very attractive for orthopaedic implant applications.

Biomechanical Phenomena↗
PubMed1983

Integrating severely adaptive handicapped seventh-grade students into constructive relationships with nonhandicapped peers in science class.

The effects of cooperative and individualistic learning experiences were compared on interactions and relationships between severely adaptive handicapped (not adapting to regular classroom demands) and nonhandicapped seventh-grade students in science classes. We investigated the predictions that (a) requiring cooperation between the two groups of students would result in increased rejection of the severely adaptive handicapped students and (b) cooperation would promote increased interpersonal attraction regardless of the heterogeneity of the students. Forty-eight suburban junior-high-school, seventh-grade students (41 nonhandicapped, 9 severely adaptive handicapped) were assigned to conditions on a stratified random basis controlling for handicap, sex, and ability level. They participated in the study for 10 days, 55 minutes per day. Results indicated that cooperative learning procedures, compared with individualistic ones, promoted more interaction and interpersonal attraction between severely adaptive handicapped and nonhandicapped students.

Achievement↗
PubMed2006

Amygdalar volume and behavioral development in autism.

CONTEXT: The amygdala is associated with socioemotional function and has been implicated in the pathophysiology of autism. OBJECTIVE: To examine the relationship between amygdalar volume at ages 3 and 4 years and severity of clinical course and outcome at 6 years of age in children with autism spectrum disorder. DESIGN: Magnetic resonance images acquired at 3 and 4 years of age were used to measure total cerebral, amygdalar, and hippocampal volumes. Acquisition of social and communication skills was assessed semiannually using the Vineland Adaptive Behavior Scales. Hierarchical linear models were used to predict variability in individual linear growth trajectories as a function of IQ, total cerebral, and amygdalar or hippocampal volumes. SETTING: Longitudinal study of children with autism spectrum disorder. PARTICIPANTS: Forty-five children with autism spectrum disorders between 3 and 6 years of age. MAIN OUTCOME MEASURE: Linear growth trajectory of age equivalence Vineland communication and social scores. RESULTS: Larger right amygdalar volume was associated with more severe social and communication impairments at ages 3 and 4 years. Larger right amygdalar volume also was predictive of poorer social and communication abilities at age 6 years, even after controlling for IQ and total cerebral volume. Parallel analyses with hippocampal volumes found no relationship to social or communication development. CONCLUSIONS: Larger right amygdalar volume at 3 and 4 years of age, but not left amygdalar, hippocampal, or total cerebral volume, is associated with a more severe clinical course and worse outcome at age 6 years in children with autism spectrum disorder. These results provide additional evidence that amygdalar development is implicated in the behavioral impairments found in autism.

Amygdala↗
PubMedDate not supplied

Gender as a predictor of burden and psychological distress of elderly husbands and wives of cancer patients.

The aim of the study is to explore whether gender is a cause of differences in the perception of burden on the part of 39 elderly wife caregivers and 21 elderly husband caregivers of cancer patients. The patients were being treated at an oncological medical center in northern Israel. At the time of interview the patients had no evidence of the disease. Stepwise regression analysis indicated that caregiver gender (i.e., husbands) and age, as well as the patient's psychological distress, predicted greater burden, although gender did not predict greater psychological distress.

Adaptation, Psychological↗
PubMed1984

The Irrational Beliefs Test: its relationship with cognitive-behavioral traits and depression.

A number of theorists have maintained that cognitive events such as irrational beliefs mediate various affective and behavioral disorders. Jones' (1968) Irrational Beliefs Test (IBT) is a prominent self-report instrument that assesses dispositional rationality-irrationality with respect to 10 beliefs proposed by Ellis. The present study with a nonclinical sample of female college students (N = 114) evaluated the relationships among the IBT, locus of control, cognitive set for success and failure, interpersonal assertion, and depression. As predicted, irrationality on the IBT and on several of its specific-belief components was related significantly to externality, negative cognitive set, unassertiveness, and self-reported depressive symptomatology. Multiple regression analyses indicated that locus of control, irrationality, and cognitive set predicted assertion and that locus of control and irrationality predicted depression.

Achievement↗
PubMed1984

A specialization of taste aversion learning during suckling and its weaning-associated transformation.

During ontogenesis, altricial mammals advance through different ecological niches which require correspondingly different adaptive strategies. We view learning as an important feature of ontogenetic adaptations and consider the acquisition and expression of taste aversion learning during nursing within this framework. Fifteen-day-old preweanling rat pups fail to acquire conditioned taste aversions while nursing, whereas 20-day-old weanlings readily learn flavor aversions while suckling (Martin & Alberts, 1979). The developmental emergence of taste aversion learning while nursing coincides with reduction in maternal milk supply and the rat pup's transition to a solid food diet. We considered the ontogenetic transformation of learning while nursing as a feeding-related adaptive strategy of the weanling rat and tested two predictions derived from this view: (1) delayed weaning might postpone acquisition or expression of suckling-related taste aversions and (2) conditions that permit weaning (e.g., access to alternate food sources) might induce acquisition or expression of such taste aversions. Both predictions were confirmed.

Animals↗
PubMed1994

Extrapolation of biodegradability test data by use of growth kinetic parameters.

Formulas for extrapolation of test data on biodegradability to percentage removal in treatment plants and biological half-life time in surface water are derived from growth kinetics. A pseudo-first-order rate constant can be used provided that substance properties and microbial density in the environment are assessed independently. For comparison of kinetics at different concentration levels an extrapolation factor can be used that is based on the ratio between maximum growth rate and sludge age in a treatment plant. The specific microbial density is estimated on the basis of proportional growth on all degradable substances in a state of equilibrium after adaptation. As a consequence the percentage removal can be predicted on the basis of sludge age and influent concentration in combination with the substance properties. The formulas predict that the combination of sewage treatment and surface water gives an almost equal biological half-life time for all readily biodegradable substances in the surface water. The predicted removal percentages and biological half-life times are in agreement with observations.

Biodegradation, Environmental↗
PubMed1987

The evolution of multicompartmental genomes in viruses.

The genetic information of many viruses is divided between separately encapsidated nucleic acid molecules. A simple evolutionary model is constructed to explain this phenomenon. All multicompartmental viruses infect plants, and most are RNA viruses. The former fact may be due to the high transmission multiplicities enjoyed by plant viruses. The latter may be due to the low replication fidelity of RNA, although another explanation is also offered. The logic of the analysis is contrasted with that of previous explanations. In particular, this paper proceeds from a "selfish DNA" viewpoint. It is not necessary to suppose that the division of the genome fills any adaptive function for the virus. The theory makes testable predictions about the parameters of multicompartmental viruses.

Biological Evolution↗
PubMed2005

Computer-driven management of prolonged mechanical ventilation and weaning: a pilot study.

OBJECTIVE: To evaluate the ability of a computer-driven system (CDS) to manage pressure-support ventilation over prolonged periods and to predict weaning readiness compared to intensivists. The system continuously adapts pressure support, gradually decreases ventilatory assistance when possible, and indicates weaning readiness. DESIGN AND SETTING: A two-center, prospective, open, clinical, pilot study in medical ICUs of two university hospitals. PATIENTS AND PARTICIPANTS: 42 consecutive mechanically ventilated patients (60+/-14 years, SAPS II 39+/-15), 9 of whom were excluded. INTERVENTIONS: As soon as patients could tolerate pressure support, they were ventilated with the CDS. The times of weaning readiness determined by the intensivists and CDS were compared. MEASUREMENTS AND RESULTS: Weaning was successful in 25 patients and failed in 7; unplanned extubation occurred in 1 patient. Time on CDS ventilation was 3+/-3 days (maximum, 12 days). The CDS detected weaning readiness earlier than the intensivists in 17 patients, and intensivists earlier than the CDS in 4; in 11 patients detection times coincided. CONCLUSIONS: A CDS was successful in fully managing pressure-support ventilation over prolonged periods and often proposed weaning readiness earlier than the intensivists did. Use of this CDS may reduce the duration of mechanical ventilation.

Adult↗