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At least 613 records · Page 34Linked to original sources
PubMed2003

A spatially explicit model simulating western corn rootworm (Coleoptera: Chrysomelidae) adaptation to insect-resistant maize.

A stochastic spatially explicit computer model is described that simulates the adaptation by western corn rootworm, Diabrotica virgifera virgifera LeConte, to rootworm-resistance traits in maize. The model reflects the ecology of the rootworm in much of the corn belt of the United States. It includes functions for crop development, egg and larval mortality, adult emergence, mating, egg laying, mortality and dispersal, and alternative methods of rootworm control, to simulate the population dynamics of the rootworm. Adaptation to the resistance trait is assumed to be controlled by a monogenic diallelic locus, whereby the allele for adaptation varies from incompletely recessive to incompletely dominant, depending on the efficacy of the resistance trait. The model was used to compare the rate at which the adaptation allele spread through the population under different nonresistant maize refuge deployment scenarios, and under different levels of crop resistance. For a given refuge size, the model indicated that placing the nonresistant refuge in a block within a rootworm-resistant field would be likely to delay rootworm adaptation rather longer than planting the refuge in separate fields in varying locations. If a portion of the refuge were to be planted in the same fields or in-field blocks each year, rootworm adaptation would be delayed substantially. Rootworm adaptation rates are also predicted to be greatly affected by the level of crop resistance, because of the expectation of dependence of functional dominance on dose. If the dose of the insecticidal protein in the maize is sufficiently high to kill >90% of heterozygotes and approximately 100% of susceptible homozygotes, the trait is predicted to be much more durable than if the dose is lower. A partial sensitivity analysis showed that parameters relating to adult dispersal affected the rate of pest adaptation. Partial validation of the model was achieved by comparing output of the model with field data on population dynamics, and with field data documenting rootworm adaptation to cyclodienes and organophosphates.

Adaptation, Physiological↗
PubMedDate not supplied

[A complex of informative indices of adaptive and compensatory mechanisms for individual prognostication of occupational hypoacusis upon exposure to noise in combination with vibration and dust].

A differential diagnostic complex of 11 physiological, anthropometric, and biochemical parameters of most informative value that reliably (over 98% reliability) characterize the status of adaptive and compensatory mechanisms upon exposure to in-plant noise in combination with local and total vibration, and dust in terms of individual noise sensitivity. Testing the proposed procedure showed its high accuracy to define the terms "exhaustion" and "normal" specific adaptation, high (81.2%) significance of individual (5-year) prediction of occupational hypoacusis, an 50%-increase in detection rates of risk groups among workers. The procedure developed is recommended to use in regular professional surveys for specific adaptation, individual prediction and detection of early disorders, to enhance the accuracy of diagnosis of occupational hypoacusis, to employ in professional selection, to define the allowable time of labour activity, and to make priority. The proposed procedure defended by copyright has been introduced into practice.

Adult↗
PubMed2007

Individual and marital adaptation in men with autism spectrum disorder and their spouses: the role of social support and coping strategies.

The aim of the present study was to examine the predictive value of social support and coping for individual and marital adaptation in adult men with autism spectrum disorder (ASD) and their spouses, based on the double ABCX model of adaptation. Twenty-one couples participated in the study and completed measures of stressor severity, social support, coping, individual and marital adaptation. Bivariate analyses showed that each of the model components was related to adaptation in men and women. Hierarchical regression analyses revealed that, after controlling for relevant demographics and stressor severity, informal support was a strong, and unique predictor of adaptation in both spouses (explained variance: 27-89%). Coping did not add to the prediction of adaptation. Clinical implications and limitations are discussed.

Adaptation, Psychological↗
PubMed1998

Thinning of the intervascular tissue layers of the human placenta is an adaptive response to passive diffusion in vivo and may help to predict the origins of fetal hypoxia.

OBJECTIVES: To test the hypothesis that thinning of the placental intervascular layers, and greater variability in thickness, are positive adaptations to facilitate passive diffusion and may help to resolve different categories of fetal hypoxia. STUDY DESIGN: Placentas from 12-41 weeks of normal gestation and from pregnancies associated with fetal hypoxic stress (high altitude, diabetes mellitus) were sampled systematically, fixed in formalin, wax-embedded and quantified using stereological methods. Arithmetic and harmonic mean distances across villous trophoblast, stroma and fetal plasma were estimated by measuring randomly sampled intercept lengths. In each case, an index of variability of layer thickness was calculated by dividing the arithmetic by harmonic mean distance. This index has the value I when a tissue layer is uniformly thick but increases in value as local layer thickness becomes more variable. Comparisons between groups were drawn using variance and regression analysis. RESULTS: During pregnancy, there were significant negative correlations between layer thickness (trophoblast, stroma) and gestational age and fetal weight, and significant positive correlations between thickness irregularity and age and weight. Compared with lowland controls, high-altitude placentas possessed thinner layers but only the trophoblast and stroma (and not fetal plasma) were more variably thick. In maternal diabetes, only fetal plasma distance was reduced but fetal and stromal layers appeared to be more irregular in thickness. CONCLUSIONS: Alterations in placental intervascular layer thicknesses occur in normal and abnormal pregnancies and represent real adaptations leading to improved diffusive conductances. Differences in the tissue location of the adaptive response may depend on the nature and origins of the fetal hypoxia.

Adaptation, Physiological↗
PubMed2026

DPAS-Graph: adaptive spatial-feature relation learning for spatial RNA-to-protein prediction and virtual protein profiling.

Paired spatial multi-omics provides a supervised basis for learning RNA-protein correspondence in situ, but predicting protein abundance from spatial transcriptomic data alone remains challenging across tissue contexts and protein panels. Here, we present DPAS-Graph, an adaptive relation-learning framework for spatial RNA-to-protein prediction. Rather than directly merging spatial proximity and transcriptomic similarity as fixed graph priors, DPAS-Graph represents them as two relation channels on a shared edge support and updates their contributions during representation learning for protein prediction. Its Niche-Coupled Field Encoder combines layer-wise edge-relation modeling, intra-branch relation refinement, and cross-branch residual correction to learn spot representations for protein abundance prediction. In a leave-one-dataset-out benchmark across seven paired spatial multi-omics datasets, DPAS-Graph achieved lower aggregate prediction errors and improved spot-level agreement of protein expression profiles, with gains mainly reflected in error-based metrics and PCC-Spot. Spatial autocorrelation and protein-derived domain agreement analyses were further used to characterize the spatial behavior of the predicted protein maps. When applied to external RNA-only spatial sections, DPAS-Graph generated qualitatively interpretable marker-level virtual protein maps, illustrating its use as a complementary tool for protein-level interpretation of transcriptomics-only spatial data.

RNA↗
PubMed1990

Differential effects of avoidant and attentional coping strategies on adaptation to chronic and recent-onset pain.

Examined the effectiveness of attentional and avoidant coping strategies for somatic, behavioral, and psychological adaptation to clinical pain. Subjects were 30 chronic and 30 recent-onset pain patients who used either attentional or avoidant coping strategies in response to their pain. Based on a review of the coping literature, it was hypothesized that subjects with recent-onset pain would demonstrate greater adaptation (lower anxiety, depression, lower pain severity and somatization ratings, and higher levels of social activity) when employing avoidant rather than attentional strategies. Chronic pain subjects using attentional strategies were predicted to demonstrate greater adaptation than chronic pain subjects using avoidant strategies. The results supported this "time x strategy" hypothesis. Implications for pain treatment programs are discussed, and suggestions are made for matching pain duration with patient coping style.

Adaptation, Psychological↗
PubMed1999

Processing images by semi-linear predictability minimization.

In the predictability minimization approach, input patterns are fed into a system consisting of adaptive, initially unstructured feature detectors. There are also adaptive predictors constantly trying to predict current feature detector outputs from other feature detector outputs. Simultaneously, however, the feature detectors try to become as unpredictable as possible, resulting in a co-evolution of predictors and feature detectors. This paper describes the implementation of a visual processing system trained by semi-linear predictability minimization, and presents many experiments that examine its response to artificial and real-world images. In particular, we observe that under a wide variety of conditions, predictability minimization results in the development of well-known visual feature detectors.

Environment↗
PubMedDate not supplied

Involvement of the rat anterior cingulate cortex in control of instrumental responses guided by reward expectancy.

The anterior cingulate cortex (ACC) plays a critical role in stimulus-reinforcement learning and reward-guided selection of actions. Here we conducted a series of experiments to further elucidate the role of the ACC in instrumental behavior involving effort-based decision-making and instrumental learning guided by reward-predictive stimuli. In Experiment 1, rats were trained on a cost-benefit T-maze task in which they could either choose to climb a barrier to obtain a high reward (four pellets) in one arm or a low reward (two pellets) in the other with no barrier present. In line with previous studies, our data reveal that rats with quinolinic acid lesions of the ACC selected the response involving less work and smaller reward. Experiment 2 demonstrates that breaking points of instrumental performance under a progressive ratio schedule were similar in sham-lesioned and ACC-lesioned rats. Thus, lesions of the ACC did not interfere with the effort a rat is willing to expend to obtain a specific reward in this test. In a subsequent task, we examined effort-based decision-making in a lever-press task where rats had the choice between pressing a lever to receive preferred food pellets under a progressive ratio schedule, or free feeding on a less preferred food, i.e. lab chow. Results show that sham- and ACC-lesioned animals had similar breaking points and ingested comparable amounts of less-preferred food. Together, the results of Experiment 1 and 2 suggest that the ACC plays a role in evaluating how much effort to expend for reward; however, the ACC is not necessary in all situations requiring an assessment of costs and benefits. In Experiment 3 we investigated learning and reversal learning of instrumental responses guided by reward predictive stimuli. A reaction time (RT) task demanding conditioned lever release was used in which the upcoming reward magnitude (five vs. one food pellet) was signalled in advance by discriminative visual stimuli. Results revealed that rats with ACC lesions were able to discriminate reward magnitude-predictive stimuli and to adapt instrumental behavior to reversed stimulus-reward magnitude contingencies. Thus, in a simple discrimination task as used here, the ACC appears not to be required to discriminate reward magnitude-predictive stimuli and to use the learned significance of the stimuli to guide instrumental behavior.

Animals↗
PubMed1997

Neuropsychological prediction of psychosocial outcome after traumatic brain injury.

The ability of neuropsychological tests to predict later psychosocial outcome on the Community Integration Questionnaire (CIQ; WiIler, Rosenthal, Kreutzer, Gordon, & Rempel, 1993) was examined. A previous investigation by Millis, Rosenthal, and Lourie (1994) found that the Trail Making Test (TMT; Lezak, 1995) and the Rey Auditory Verbal Learning Test (RAVLT; Lezak, 1995) were related to performance on the CIQ at 1 year postinjury. The RAVLT and the TMT Parts A and B (TMT-A, TMT-B) in conjunction with age at time of injury significantly predicted psychosocial outcome as measured by individual self-report. When self-reported functioning was examined by domain, these variables significantly predicted home and social adaptation. These variables were applied to significant others' reports of community integration, where age and the TMT remained significant predictors of psychosocial outcome. These results underscore the utility of neuropsychological measures in the prediction of later community integration after traumatic brain injury.

Journal Article↗
PubMed2000

Refining a measure of brain injury sequelae to predict postacute rehabilitation outcome: rating scale analysis of the Mayo-Portland Adaptability Inventory.

OBJECTIVE: Evaluate the psychometric properties of the Mayo-Portland Adaptability Inventory (MPAI). DESIGN: Rating scale (Rasch) analysis of MPAI and principal component analysis of residuals; the predictive validity of the MPAI measures and raw scores was assessed in a sample from a day rehabilitation program. SETTING: Outpatient brain injury rehabilitation. PARTICIPANTS: 305 persons with brain injury. RESULTS: A 22-item scale reflecting severity of sequelae of brain injury that contained a mix of indicators of impairment, activity, and participation was identified. Scores and measures for MPAI scales were strongly correlated and their predictive validities were comparable. CONCLUSIONS: Impairment, activity, and participation define a single dimension of brain injury sequelae. The MPAI shows promise as a measure of this construct.

Activities of Daily Living↗
PubMed1998

New evidence for the zoom lens model using the RSVP technique.

A main prediction from the zoom lens model for visual attention is that performance is an inverse function of the size of the attended area. The "attention shift paradigm" developed by Sperling and Reeves (1980) was adapted here to study predictions from the zoom lens model. In two experiments two lists of items were simultaneously presented using the rapid serial visual presentation technique. Subjects were to report the first item he/she was able to identify in the series that did not include the target (the letter T) after he/she saw the target. In one condition, subjects knew in which list the target would appear, in another condition, they did not have this knowledge, having to attend to both positions in order to detect the target. The zoom lens model predicts an interaction between this variable and the distance separating the two positions where the lists are presented. In both experiments, this interaction was observed. The results are also discussed as a solution to the apparently contradictory results with regard to the analog movement model.

Adult↗
PubMed2004

Prism adaptation in visually mature patients with esotropia of childhood onset.

OBJECTIVE: To investigate the role of prism adaptation in the visually mature population with esotropia onset before visual maturation. DESIGN: Retrospective, noncomparative case series. PARTICIPANTS: Eighty-five patients, 26 prism adapted for near (PAN) and 59 prism adapted for distance (PAD), were included in the study. METHODS: Patients included in this study were older than 9 years and had esotropia with an onset before age 9. Mean follow-up was 30 months (range = 6 weeks-164 months). All patients had prism adaptation and subsequent surgical correction. Surgical success was defined as peripheral fusion on the Worth 4-dot test and < or = 8(Delta) deviation at near and distance on the simultaneous prism and cover test. MAIN OUTCOME MEASURES: Response to preoperative prism adaptation and postoperative alignment and sensory results were examined. RESULTS: Twenty-six of the 85 patients had previous surgical esotropia correction. In the PAD group, 41 were responders. Seventeen of these had built their deviation > or = "0" > 10(Delta) with prism adaptation. All responders had surgery for their prism-adapted angle. Postoperatively, 34 of 41 (83%) responders and 6 of 18 (33%) nonresponders had fusion. In the PAN group, 17 were responders. Nine of these built their deviation with prisms. Postoperatively, 16 of 17 (94%) responders and builders and 1 of 9 (11%) nonresponders had successful surgery with sensory and motor fusion. CONCLUSIONS: Adults with esotropia onset before visual maturation can be prism adapted and surgically treated with a predictable outcome of sensory and motor fusion. Those prism adapted for near with response can be successfully treated with surgery for the near deviation. Prism adaptation also aids in determining those who would benefit from larger amounts of surgery.

Adaptation, Ocular↗
PubMedDate not supplied

Autocorrelation method adapted to generate new atomic environments: application for the prediction of 13-C chemical shifts of alkanes.

The concept of the multifunctional autocorrelation method governing global description of molecules was changed in order to take into account the structural environment of each atom. New atomic environments are generated as possible descriptors in QSARs and can be useful for database characterization. The principles of this approach are widely explained through a case study dealing with the design of a model allowing the simulation of the carbon-13 nuclear magnetic spectra for alkanes. Carbon atoms in alkanes are described by using as structural descriptors a vector corresponding to only four components vectors of the multifunctional autocorrelation method. The statistical method used for deriving the model was a classical three-layer feedforward neural network trained by the back-propagation algorithm and multilinear regression (MLR). The predictive ability of the ANN model was tested by -10%-out(L10%O) cross-validation method, demonstrating the superior quality of the neural model. The established model allows us the prediction of the 13-C chemical shifts with success because since all types of carbons are taken into account without distinction of connectivity. The neural network possessed a 4:7:1 architecture with a sigmoid shape as a activation function. The model produced a cross-validation standard coefficient r between delta(exp) and delta(calc) about 0.99, while the cross-validation standard s and the mean error are equal to 0.87 and 0.60 ppm, respectively.

Journal Article↗
PubMed2000

An intelligent diabetes software prototype: predicting blood glucose levels and recommending regimen changes.

Maintaining optimal blood glucose (BG) control is difficult for type 1 diabetes mellitus (T1DM) patients when typical daily regimens of food, insulin and exercise are altered. Artificial intelligence (AI) systems consisting of treatment algorithms calibrated through large datasets of patient specific information may offer a solution. Such a system can predict BG level changes resulting from regimen disturbances and recommend regimen changes for compensation. A software prototype based on neural network, fuzzy logic, and expert system concepts was developed and evaluated to determine feasibility and efficacy of a patient specific prediction model. BG data are the primary driver for adapting existing functions to patient specific prediction algorithms. Mean absolute percent error (MAPE) between actual and predicted BG values from inputs of daily insulin, food, and exercise information for an T1DM test subject was 10.5% using a calibrated model. The prototype is limited by the requirement for a rigid testing schedule, human error and situational circumstances such as alcohol consumption, illness, infection, stress, and significant hormonal imbalances. No significant conclusions regarding model validity can be drawn due to limited evaluation process and subject sample size, although the prototype has demonstrated viability as a learning tool for diabetes patients. Increased impetus for further development of this prototype and similar AI models may materialize when more effective diagnostic and data capture tools become available to reduce testing and improve accuracy of the model with more input data.

Algorithms↗
PubMed2001

Load transfer and stress shielding of the hydroxyapatite-ABG hip: a study of stem length and proximal fixation.

We questioned whether the excellent clinical results reported for the hydroxyapatite-coated ABG hip are consistent with results of preclinical computer simulation methods for the prediction of strain-adaptive bone remodeling patterns around implants. We also investigated whether a further improvement of the results can be expected if complete proximal load transfer is enforced by reducing stem length to the metaphyseal area only. Resorption patterns predicted were in good agreement with radiographic clinical findings. Mechanical failure of the bone-implant interface was judged based on a Hoffman interface stress criterion, which was low. Reducing stem length hardly increased interface failure probability, but it did not reduce stress shielding, either. From a mechanical point of view, reducing stem length to the metaphyseal area only is not advantageous.

Arthroplasty, Replacement, Hip↗
PubMed2004

The relationships between organizational and individual variables to on-the-job driver accidents and accident-free kilometres.

Highway fatalities are the leading cause of fatal work injuries in the US, accounting for approximately 1 in 4 of the 5900 job-related deaths during 2001. The present study focused on the contribution of organizational factors and driver behaviours to on-the-job driving accidents in a large Western Canadian corporation. A structural equation modelling (SEM) approach was used which allows researchers to test a complex set of relationships within a global theoretical framework. A number of scales were used to assess organizational support, driver errors, and driver behaviours. The sample of professional drivers that participated allowed the recording of on-the-job accidents and accident-free kilometres from their personnel files. The pattern of relationships in the fitted model, after controlling for exposure and social desirability, provides insight into the role of organizational support, planning, environment adaptations, fatigue, speed, errors and moving citations to on-the-job accidents and accident-free kilometres. For example, organizational support affected the capacity to plan. Time to plan work-related driving was found to predict accidents, fatigue and adaptations to the environment. Other interesting model paths, SEM limitations, future research and recommendations are elaborated.

Accidents, Occupational↗
PubMed2006

Precise adaptation in bacterial chemotaxis through "assistance neighborhoods".

The chemotaxis network in Escherichia coli is remarkable for its sensitivity to small relative changes in the concentrations of multiple chemical signals over a broad range of ambient concentrations. Key to this sensitivity is an adaptation system that relies on methylation and demethylation (or deamidation) of specific modification sites of the chemoreceptors by the enzymes CheR and CheB, respectively. It was recently discovered that these enzymes can access five to seven receptors when tethered to a particular receptor. We show that these "assistance neighborhoods" are necessary for precise adaptation in a model for signaling by clusters of chemoreceptors. In agreement with experiment, model clusters composed of receptors of different types exhibit high sensitivity and precise adaptation over a wide range of chemical concentrations and the response of adapted clusters to addition/removal of attractant scales with free-energy change. We predict two limits of precise adaptation at large attractant concentrations: Either receptors reach full methylation and turn off, or receptors become saturated and cease to respond to attractant but retain their adapted activity.

Adaptation, Physiological↗