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PubMedDate not supplied

Cognitive adaptation as a predictor of new coronary events after percutaneous transluminal coronary angioplasty.

OBJECTIVE: We tested whether the psychological components of cognitive adaptation theory would predict new coronary events after a first percutaneous transluminal coronary angioplasty (PTCA). METHODS: A consecutive sample of patients treated successfully with PTCA were enrolled in the study. Of 343 patients approached, 303 (88%) agreed to participate and were interviewed shortly before hospital discharge. We measured the components of cognitive adaptation theory (optimism, self-esteem, and mastery) during the interview. Five patients were excluded from the analysis because of early, in-hospital reocclusion. New cardiac events (coronary artery bypass grafting, PTCA, myocardial infarction, or disease progression) were examined within 6 months of the first PTCA. We obtained 6-month follow-up data on 98% of patients. RESULTS: The cognitive adaptation index predicted new cardiac events, even when demographic variables and medical variables thought to predict restenosis were statistically controlled (p = .02). CONCLUSIONS: These results suggest that persons who respond to their illness by perceiving control over their futures, by having positive expectations about their futures, and by holding a positive view of themselves seem to be at less risk for a new cardiac event after a first PTCA.

Adaptation, Psychological↗
PubMed2025

Resource presentation dictates genetic and phenotypic adaptation in yeast.

BACKGROUND: Environments shape adaptive trajectories of populations, often leading to adaptive parallelism in identical, and divergence in different environments. However, how does the likelihood of these possibilities change with minute changes in the environment remain unclear. RESULTS: In this study, we evolved Saccharomyces cerevisiae in environments which differed only in the manner in which the sugar source is presented to the population. In one set of populations, carbon was presented as a mixture of glucose-galactose, and in the other, as melibiose, a glucose-galactose disaccharide. Since the two environments differed in how the two monosaccharides are packaged, we call these environments 'synonymous'. Our results show that even subtle environmental differences can lead to differing phenotypic responses between the two sets of evolved populations. However, despite different adaptive responses, pleiotropic effects of adaptation are largely predictable. We also show that distinct genomic targets of adaptation between the two sets of evolved populations are functionally convergent. CONCLUSION: This study highlights how subtle environmental differences dictate phenotypic and genetic adaptation of populations. Additionally, these results also suggest the predictive potential of ancestor's fitness in understanding pleiotropic responses. Our work underscores the importance of studying more such environments to understand the generality of adaptive responses in populations.

Saccharomyces cerevisiae↗
PubMed1997

[Comparison of predictive methods of Sugi (Cryptomeria) atmospheric pollen counts using mean temperature, solar radiation and male flowering index--an example of Toyama Prefecture].

The previous years mean temperature of July, total solar radiation of July and August and the male flowering index were used to predict atmospheric pollen counts. We examined the adaptability of these predictions and we get following results: 1. Following good harvest years of male flower, atmospheric pollen counts predicted by previous year's mean temperature of July and the total solar radiation of July and August are higher than the actual atmospheric pollen count. 2. Prediction of atmospheric pollen counts by factors within the previous five years are more exact because matured Cryptomeria forests are increasing yearly. 3. There are few errors in prediction by the flowering index because the flower index reflects the actual harvest of male flower.

Air↗
PubMed1997

The association between adaptive and cognitive deficits in geriatric chronic schizophrenic patients.

Cognitive impairments have been shown to predict impairments in adaptive functioning in patients with chronic schizophrenia and to be more predictive of overall outcome than positive or negative symptoms of the illness. Both adaptive and cognitive impairments are multidimensional, and it is possible that correlations between these domains may be limited to certain aspects of these functions. In this study, 208 geriatric patients with chronic schizophrenia were examined with a cognitive battery and assessed with a structured scale to determine the extent of their adaptive functions. Instrumental and social skills deficits were more strongly correlated with cognitive impairments than with the severity of undercontrolled behavior. Each of the cognitive measures was correlated with global social-adaptive deficits, with minimal variation in the magnitude of correlations. These results suggest that interventions should be individually targeted to cognitive-adaptive impairments and undercontrolled behavior.

Age Factors↗
PubMed2001

Performance of an adaptive beamforming noise reduction scheme for hearing aid applications. I. Prediction of the signal-to-noise-ratio improvement.

Adaptive beamformers have been proposed as noise reduction schemes for conventional hearing aids and cochlear implants. A method to predict the amount of noise reduction that can be achieved by a two-microphone adaptive beamformer is presented. The prediction is based on a model of the acoustic environment in which the presence of one acoustic target-signal source and one acoustic noise source in a reverberant enclosure is assumed. The acoustic field is sampled using two omnidirectional microphones mounted close to the ears of a user. The model takes eleven different parameters into account, including reverberation time and size of the room, directionality of the acoustic sources, and design parameters of the beamformer itself, including length of the adaptive filter and delay in the target signal path. An approximation to predict the achievable signal-to-noise improvement based on the model is presented. Potential applications as well as limitations of the proposed prediction method are discussed and a FORTRAN subroutine to predict the achievable signal-to-noise improvement is provided. Experimental verification of the predictions is provided in a companion paper [J. Acoust. Soc. Am. 109, 1134 (2001)].

Acoustics↗
PubMedDate not supplied

Predictors of coping with pain in mothers and their children with sickle cell syndrome.

OBJECTIVE: This study examined predictors of strategies used to cope with pain in children with sickle cell disease and their mothers. METHOD: Disease severity, socioeconomic status, child adjustment and adaptive behavior, maternal psychopathology, and family functioning were examined in 55 mother-child dyads to determine the predictive potential of these factors on engagement and disengagement coping. RESULTS: While controlling for socioeconomic status and psychopathology in the mothers, 15% of the variance in engagement coping was predicted by family adaptability. Disengagement coping was predicted by internalizing symptoms exhibited by the child, including a negative and pessimistic attributional style, which accounted for nearly one fifth of the variance. Finally, mothers who reported more active strategies for coping with their child's pain were more likely to endorse greater use of techniques to prevent and effectively manage pain in their children. CONCLUSIONS: Neither coping strategy was predicted by severity of disease presentation in the children, suggesting the importance of psychosocial factors in adapting to childhood chronic illness and that severity of disease may not necessarily be a marker for families at risk for adjustment difficulties. Findings were interpreted to support a systemic family model in promoting active and adaptive engagement coping in caretakers of children with sickle cell syndrome.

Adaptation, Psychological↗
PubMed2004

Geographic variation of caste structure among ant populations.

Morphologically distinct worker castes of eusocial insects specialize in different tasks. The relative proportions of these castes and their body sizes represent the demography of a colony that is predicted to vary adaptively with environments. Despite strong theoretical foundations, there has been little empirical evidence for the evolution of colony demography in nature. We show that geographically distinct populations of the ant Pheidole morrisi differ in worker caste ratios and worker body sizes in a manner consistent with microevolutionary divergence. We further show that the developmental mechanism for caste determination accounts for the unique pattern of covariation observed in these two traits. Behavioral data reveal that the frequency of different tasks performed by workers changes in a caste-specific manner when caste ratios are altered and demonstrate the importance of the major caste in colony defense. The population-level variation documented here for P. morrisi colonies supports the predictions of adaptive demography theory and illustrates that developmental mechanisms can play a significant role in shaping the evolution of phenotype at the colony level.

Adaptation, Biological↗
PubMed1977

Analysis of chromatic-adaptation effect by a linkage model.

Hunt suggested that an adaptation-dependent linkage in the visual pathway from the retina to the brain can explain the variation of saturation produced by change of adapting luminance. If variation of saturation is caused by change of linkage, this change must also be involved in chromatic adaptation to light sources that have different chromaticities. By considering the effective adaptation levels of receptors, the model is extended and formulated for application to prediction of chromatic adaptation. It is tested by use of experimental results for chromatic adaptation obtained by Burnham et al. Suitable selection of parameters that specify the state of linkage produces good predictions of the effects of chromatic adaptation.

Adaptation, Ocular↗
PubMed2003

Database mining with adaptive fuzzy partition: application to the prediction of pesticide toxicity on rats.

A data set of 235 pesticide compounds, divided into three classes according to their toxicity toward rats, was analyzed by a fuzzy logic procedure called adaptive fuzzy partition (AFP). This method allows the establishment of molecular descriptor/chemical activity relationships by dynamically dividing the descriptor space into a set of fuzzily partitioned subspaces. A set of 153 molecular descriptors was analyzed, including topological, physicochemical, quantum mechanical, constitutional, and electronic parameters, and the most relevant descriptors were selected with the help of a procedure combining genetic algorithm concepts and a stepwise method. The ability of this AFP model to classify the three toxicity classes was validated after dividing the data set compounds into training and test sets, including 165 and 70 molecules, respectively. The experimental class was correctly predicted for 76% of the test-set compounds. Furthermore, the most toxic class, particularly important for real applications of the toxicity models, was correctly predicted in 86% of cases. Finally, a comparison between the results obtained by AFP and those obtained by other classic classification techniques showed that AFP improved the predictive power of the proposed models.

Algorithms↗
PubMed2001

Status change during adulthood: life-history by-product or kin selection based on reproductive value?

When dominance status predicts fitness, most adaptive models of dominance relationships among cercopithecine primate females predict lifetime maintenance of status. These models and alternative ones positing rank decline as a non-adaptive by-product have remained largely untested, however, because lifetime status of older adults has been virtually unknown for natural populations. In a 25-year study of adult female savannah baboons (Papio cynocephalus), in each of three social groups, rank losses were common among the 66 females that lived past median adult age. These losses were not accounted for by loss in relative rank from group growth or by loss in absolute rank from reversals in rank between members of different maternal families or between sisters. Rather, females that had mature daughters experienced loss of dominance status to these offspring, a characteristic of all but the top-ranking matriline of each group. Among proposed hypotheses for rank reversals between adults, that of kin selection based on relative reproductive value is most clearly supported by these data. In contrast, observed patterns of rank loss are not consistent with alternative models that postulate that changes during adult lifespan are a product of accumulated risk, physical decline during ageing, or coalitionary support among females within or between matrilines.

Aging↗
PubMed1978

An analysis of rod outer segment adaptation based on a simple equivalent circuit.

This model of rod outer segment adaptation is based on the hypothesis that transmitter substance released by bleached rhodopsin closes sodium channels in the outer segment plasma membrane, leading to hyperpolarization of the receptor. The outer segment adaptation processes of the model are associated with the transmitter release, the transmitter background concentration and the plasma membrane leakage. Changes in the three model parameters correspond to the three types of outer segment adaptation process. According to the model the stimulus-response function is in every adaptational state U/Umax = I/(I + IH). The model predicts how each adaptation process affects IH and Umax. Specifically, when the number of liberated transmitter molecules per isomerizing quantum decreases, the amplitude Umax remains constant but IH increases. A short description of this model has been published in a paper reporting experimental results on background adaptation (Hemilä, 1977).

Adaptation, Ocular↗
PubMed2005

Communities adjust their temperature optima by shifting producer-to-consumer ratio, shown in lichens as models: II. Experimental verification.

The community adaptation hypothesis [7] predicts that lichens, simple communities of microorganisms, can adapt to a wide range of thermal regimes by regulating the ratio of primary producers (algae) and consumers (fungi): R(p/c). To test this hypothesis, we determined R(p/c) values by image analysis of cross sections of herbarium specimens of the lichen Cladina rangiferina, which is widely distributed between the Arctic and the tropics. We found that R(p/c) for C. rangiferina increases with summer temperature by more than one order of magnitude, consistent with the hypothesis. To assess the ecological significance of community adaptation (R(p/c) regulation), other adaptive mechanisms (e.g., photobiont substitution, genetic adaptation, and photosynthetic acclimation in North American Cladina spp.) were studied. Laboratory investigations with algae and fungi isolated in culture from live specimens suggested that the role of these mechanisms is relatively minor and cannot account for the high degree of lichen adaptability.

Adaptation, Physiological↗
PubMed2001

The size-tuning of the face-distortion after-effect.

Recently, Webster and MacLin demonstrated a face-distortion after-effect (FDAE) for both upright and inverted faces: adaptation to a distorted face makes a normal face appear distorted in the direction opposite to the adapting direction. Neurophysiological studies (e.g. Experimental Brain Research 65 (1986) 38) show that face-selective neurons in the superior temporal sulcus (STS) are remarkably size-invariant in their responses. If the site of adaptation underlying the FDAE is the homologous neuron population in human vision, then the FDAE should also be highly tolerant to changes in size between adapting and test faces. Here, we test this prediction. Observers were adapted to distorted upright/inverted faces of three different sizes (3.3 degrees x 3.7 degrees, 6.6 degrees x 7.5 degrees, and 13.1 degrees x 14.8 degrees ). For adapting faces of all three sizes, observers adjusted test faces of all three sizes until they appeared normal. Significant FDAEs were observed in all conditions. For both upright and inverted faces, FDAEs were approximately twice as strong when adapting and test faces were the same size than when they differed by even a single octave in size. The magnitudes of FDAEs were comparable for upright and inverted faces. The larger FDAEs for same-size adapting and test faces suggest that part of the FDAE derives from a neuron population with narrow size-tuning. However, the significant FDAEs obtained for adapting and test images differing by two octaves implicate a different neuron population with broad size-tuning, possibly the human homolog of the face-selective neuron population in monkey STS.

Afterimage↗
PubMed1989

Social environment and adjustment after laryngectomy.

The relationship between social environmental variables and psychological, physical, and speech dysfunction after laryngectomy surgery was examined. The relationships between these categories of dysfunction and the following three social environmental factors were examined: (1) acceptance and emotional support from family and friends; (2) disease-specific support from peers who have had the same surgical intervention and from professionals; and (3) socioeconomic status (SES). Data were collected from 60 total laryngectomy patients an average of 24.3 months after surgery. The type of support provided was different for each source of support, family-friend or peer-professional. Interpersonal support from family and friends was strongly associated with psychosocial and physical dysfunction but had a weaker association with speech adjustment. Diseases-specific support from speech therapists and other laryngectomees was a weaker predictor of dysfunction but a stronger predictor of communication adaptation. SES was not predictive of dysfunction or communication adaptation. Thus different sources of social support can make specific contributions to minimizing physical and psychosocial dysfunction and acquiring skills to overcome the limitations imposed by the surgery.

Adaptation, Psychological↗
PubMed1986

Interpreting trans-retinal recordings of spectral sensitivity.

A quantitative model is developed to describe spectral sensitivity functions recorded extracellularly from heterogeneous populations of receptors in different states of adaptation. This treatment identifies the most important influences and clarifies several general features of experimental results. The shapes of retinal spectral sensitivity curves in different states of chromatic adaptation depend in predictable fashion on whether the primary effect of the adapting light on individual receptors is to decrease Vmax (response compression) or to increase the quantum demand for half-saturation. Some response compression is necessary in order for one or more receptors to drop out of the response at modest levels of adaptation. The apparent ease of adaptation also depends on the criterion voltage, particularly in the presence of response compression. The technique of selective adaptation of the ERG is capable of revealing the presence of receptors that comprise only a few percent of the total population. The short wavelength absorption of all visual pigments normally makes it impossible to use uv or violet light to adapt selectively those receptors with maximal sensitivity in the uv or violet region of the spectrum while sparing receptors with maximal sensitivity at longer wavelengths. The presence of cone oil droplets absorbing at short wavelengths, however, can effectively screen visual pigments in some of the receptors from uv or violet adapting lights.

Adaptation, Ocular↗
PubMed2004

Nonlinear model predictive control of glucose concentration in subjects with type 1 diabetes.

A nonlinear model predictive controller has been developed to maintain normoglycemia in subjects with type 1 diabetes during fasting conditions such as during overnight fast. The controller employs a compartment model, which represents the glucoregulatory system and includes submodels representing absorption of subcutaneously administered short-acting insulin Lispro and gut absorption. The controller uses Bayesian parameter estimation to determine time-varying model parameters. Moving target trajectory facilitates slow, controlled normalization of elevated glucose levels and faster normalization of low glucose values. The predictive capabilities of the model have been evaluated using data from 15 clinical experiments in subjects with type 1 diabetes. The experiments employed intravenous glucose sampling (every 15 min) and subcutaneous infusion of insulin Lispro by insulin pump (modified also every 15 min). The model gave glucose predictions with a mean square error proportionally related to the prediction horizon with the value of 0.2 mmol L(-1) per 15 min. The assessment of clinical utility of model-based glucose predictions using Clarke error grid analysis gave 95% of values in zone A and the remaining 5% of values in zone B for glucose predictions up to 60 min (n = 1674). In conclusion, adaptive nonlinear model predictive control is promising for the control of glucose concentration during fasting conditions in subjects with type 1 diabetes.

Blood Glucose↗
PubMed1992

A square root law for adaptation to contrast?

Several characteristic of aftereffects (especially the motion aftereffect) depend upon the square root of the time spent adapting. The same parameters are here examined for the contrast threshold elevation aftereffect. The time taken to recover is shown to be well predicted by root adaptation time (beyond a minimum duration), but the amount of threshold elevation, the rate of recovery and the integrated recovery phase cannot be so predicted.

Adaptation, Ocular↗
PubMed2002

The relationship between executive function abilities, adaptive behaviour, and academic achievement in children with externalising behaviour problems.

BACKGROUND: Specific domains of adaptive behaviours and academic achievement may, in part, depend on executive function capacities. Executive function deficits have been found to be associated with Attention Deficit Hyperactivity Disorder (ADHD), not Oppositional Defiant Disorder/Conduct Disorder (ODD/CD). METHOD: Using a sample of 110 adolescents, comprising four groups, ADHD only, co-morbid ADHD and ODD/CD, ODD/CD only, and a normal community control group, we assessed socialisation and communication skills with the Vineland Adaptive Behaviour Scales, along with reading ability, and executive functioning. RESULTS: Poorer adaptive communication skills were specifically associated with ADHD when compared with either ODD/CD or the control group, and the social competence of adolescents with ADHD was as low as the levels associated with ODD/CD. Presence of ADHD was associated with lower word recognition scores, while the reading levels of adolescents with ODD/CD were equivalent to those without behaviour problems. Executive function test scores correlated with all adaptive behaviour outcomes. Multiple regression analyses indicated that verbal ability predicted communication and reading scores, with executive function abilities contributing significant variance to the prediction in the adaptive behaviour, communication, and socialisation domains. CONCLUSIONS: Further research with other samples, both community and clinical groups, is needed to assess the generalisability of the findings. Small numbers of girls in the groups gave us insufficient power to adequately address potential gender differences.

Achievement↗