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 739 records · Page 41Linked to original sources
PubMed2004

Ketamine/xylazine anesthesia for radiologic imaging of neurologically impaired rats: dose response, respiratory depression, and management of complications.

In vivo imaging of rats represents an important tool for outcome evaluation in research on stroke, brain trauma, and other neurologic diseases. Since sedation of animals is necessary to avoid artifacts, a mixture of ketamine and xylazine is frequently used for anesthesia. We assessed the suitable dosage of narcotics and its correlation to severe respiratory adverse events in 269 cases of ketamine/xylazine anesthesia in male Wistar rats for performance of magnetic resonance imaging after middle cerebral artery occlusion (MCAO) or sham surgery. Anesthesia depth was not measured. Anesthesia was efficacious in avoiding movement artifacts during imaging. Necessary dosage was lower if rodents were subjected to MCAO instead of sham surgery, if body weight was below baseline, and if time since surgery was short. If anesthesia was induced during the first 2 days after surgery in animals with body weight loss, necessary dose rates were 27% below doses required for rats more than 10 days post-surgery with body weight above baseline (91.4/8.3 versus 125.1/11.3 mg of ketamine/xylazine/kg). A dose adaptation scale for the prediction of necessary dose rates was developed. Apnea developed in 3.3% of all animals. Use of ketamine/xylazine anesthesia for imaging procedures is feasible and safe, though it is associated with a small risk of respiratory arrest. In case of apnea, inspiration can be provoked by a puff of air into the rat's pelt. If unsuccessful, endotracheal intubation and mechanical ventilation are needed until spontaneous breathing is restored or xylazine effects are antagonized.

Anesthesia↗
PubMed2005

Predicting missing values in a home care database using an adaptive uncertainty rule method.

OBJECTIVES: Contemporary literature illustrates an abundance of adaptive algorithms for mining association rules. However, most literature is unable to deal with the peculiarities, such as missing values and dynamic data creation, that are frequently encountered in fields like medicine. This paper proposes an uncertainty rule method that uses an adaptive threshold for filling missing values in newly added records. A new approach for mining uncertainty rules and filling missing values is proposed, which is in turn particularly suitable for dynamic databases, like the ones used in home care systems. METHODS: In this study, a new data mining method named FiMV (Filling Missing Values) is illustrated based on the mined uncertainty rules. Uncertainty rules have quite a similar structure to association rules and are extracted by an algorithm proposed in previous work, namely AURG (Adaptive Uncertainty Rule Generation). The main target was to implement an appropriate method for recovering missing values in a dynamic database, where new records are continuously added, without needing to specify any kind of thresholds beforehand. RESULTS: The method was applied to a home care monitoring system database. Randomly, multiple missing values for each record's attributes (rate 5-20% by 5% increments) were introduced in the initial dataset. FiMV demonstrated 100% completion rates with over 90% success in each case, while usual approaches, where all records with missing values are ignored or thresholds are required, experienced significantly reduced completion and success rates. CONCLUSIONS: It is concluded that the proposed method is appropriate for the data-cleaning step of the Knowledge Discovery process in databases. The latter, containing much significance for the output efficiency of any data mining technique, can improve the quality of the mined information.

Algorithms↗
PubMed2006

Standing genetic variance for female resistance to harm from males and its relationship to intralocus sexual conflict.

Interlocus sexual conflict theory predicts that some male adaptations are harmful to their mates. Females are therefore expected to evolve resistance to this harm. Using cytogenetic cloning techniques, we tested for heritable genetic variation among females for resistance to harm from males and determined whether propensity to remate, female body size, and intralocus conflict contributes to this variation. We found low but significant heritability for female resistance, but this variation accounted for more than half of the standing genetic variation for net fitness among females. We found no association between female resistance and female body size or level of intralocus sexual conflict. Reluctance to remate was found to be an important factor contributing to the female resistance phenotype, and we found a positive selection gradient on this trait. However, we observed only a nonsignificant positive correlation between a female's resistance and her net fitness. One factor contributing to the observed nominal level of selection on female resistance was that males cause the greatest amount of harm to females with the highest intrinsic fecundity.

Adaptation, Physiological↗
PubMed1991

Development of the coping health inventory for children.

This report describes the development of the Coping Health Inventory for Children (CHIC), an instrument designed to provide a systematic assessment of coping behaviors of chronically ill school-aged children. Using a hierarchical approach to the organization of behavior, 45 specific coping behaviors used by chronically ill children were identified and then combined into five conceptually distinct patterns of coping: Develops Competence and Optimism; Feels Different and Withdraws; Is Irritable, Moody, and Acts Out; Complies With Treatment; and Seeks Support. Results of confirmatory factor analysis and predicted relationships with child adaptation measures provide support for construct validity. Good internal consistency and stability reliabilities were also found.

Adaptation, Psychological↗
PubMed1988

Ocular torsion in upright and tilted positions during hypo- and hypergravity of parabolic flight.

Four subjects considered resistant to motion sickness were tested in KC-135 parabolic flight to examine ocular torsion at hypo- and hypergravity. Three of these showed no significant torsion at zero G in either the upright position or when tilted 30 degrees to right or left. At 1.8 G in the tilted positions they showed greater ocular counterrolling than at 1 G. None of these three subjects became motion sick. The fourth subject showed eye torsion toward his left in all positions at zero G. This leftward bias could also be seen at 1.8 G when tilted left ear down, the side that induces rightward counterrolling. There he had less eye torsion than at 1 G. This subject became motion sick. All subjects had normal counterrolling in ground-based testing. These results support the hypothesis that asymmetry of the utricular system may be well compensated in the normal 1 G environment, but unmasked in unaccustomed gravitational situations, suggesting a possible predictive test for space adaptation syndrome.

Adult↗
PubMed1994

[Labor stress and postpartum neonatal weight development].

55 years ago the term "stress" was defined as a general reaction pattern which, in moderation, is not only unharmful but even has a vital function. Does this also apply to intrapartal fetal stress? The results from a retrospective pilot study including 791 mature newborns without major disorders are presented to stimulate discussion and possibly give rise to prospective studies. 1. Newborns from primigravidas with labour spanning more than 12 hours incurred postpartal weight loss in excess of 5% of their birthweight only half as often as infants with shorter delivery periods. In other words, a longer expulsion phase tended to be correlated with lower postpartal weight loss in neonates. 2. As expected, the 1-minute-Apgar score was no statistically valid predictive parameter for the adaptation phase in the first 5 postpartal days of newborns. Infants with 1-minute Apgar scores of up to 6 had reached their birth-weight on the 5th postpartal day rather more often than those with better 1-minute Apgar scores. 3. In the group of mature newborns involving premature rupture of the membranes a marked gain on birthweight up to the 5th postpartal day was seen only half as often as in the group with rupture of membranes at term. 4. Weight loss of only slight proportions was seen in newborns admitted to the pediatric hospital because of suspected intra-amniotic infection half as often, compared to the other infants who also reached their birthweight faster than those with suspected intra-amniotic infection. 5. Oxytocin administered to aid labour had a positive effect on postpartal weight development.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1996

Postural control in the older adult.

Age-related changes in the neural, sensory, and musculoskeletal systems can lead to balance impairments that have a tremendous impact on the ability to move about safely. The many complex substrates of the posture control system subserve a common functional goal: regulation of the relationship between the center of mass and the base of support. Traditional approaches, which have focused on the control of the center-of-mass displacement, have documented age-related changes in "feet-in-place" responses: during quiet standing, during volitional movement, or in response to applied perturbation. Recently, increasing attention has been directed toward the control of the base of support, that is, compensatory leg and arm movement, as an important element of the postural repertoire, and early results suggest profound age-related impairment in the control of compensatory stepping movements. For both feet-in-place and stepping responses, control of lateral stability appears to be a major problem associated with increased risk of falling. In view of age-related differences in ability to adapt postural responses under predictable task conditions, future work will likely benefit by mimicking, as much as possible, the varied and unpredictable nature of the events that often precipitate falls in daily life, in order to draw connections between the laboratory or clinic and "real-life" stability.

Accidental Falls↗
PubMed1997

Toward implementation of artificial neural networks that "really work".

Artificial neural networks are established analytical methods in bio-medical research. They have repeatedly outperformed traditional tools for pattern recognition and clinical outcome prediction while assuring continued adaptation and learning. However, successful experimental neural networks systems seldom reach a production state. That is, they are not incorporated into clinical information systems. It could be speculated that neural networks simply must undergo a lengthy acceptance process before they become part of the day to day operations of health care systems. However, our experience trying to incorporate experimental neural networks into information systems lead us to believe that there are technical and operational barriers that greatly difficult neural network implementation. A solution for these problems may be the delineation of policies and procedures for neural network implementation and the development a new class of neural network client/server applications that fit the needs of current clinical information systems.

Hospital Information Systems↗
PubMed1997

Diaphyseal bone growth and adaptation: models and data.

The cross-sectional growth and development of the long bone diaphysis is strongly influenced by in vivo mechanical loading. An analytical approach was developed to model these mechanobiologic influences. First, human growth under normal loading conditions was modeled. Our model predictions were validated by comparison to human data obtained during adolescence. Next, skeletal adaptation during growth under altered loading conditions was examined using an animal model. Rat hindlimb suspension experiments were performed and femoral adaptation to reduced loading during growth was measured and compared to normal controls. Then our model predictions of adaptation during growth were compared directly to our experimental data.

Adaptation, Physiological↗
PubMed2002

Prediction of employment status following traumatic brain injury using a behavioural measure of frontal lobe functioning.

OBJECTIVE: To examine whether a behavioural measure of frontal lobe functioning, the Brock Adaptive Functioning Questionnaire (BAFQ), could predict employment status following traumatic brain injury (TBI). DESIGN: A discriminant function analysis was conducted to determine the ability of the BAFQ, along with other factors, to predict occupational status post-injury. METHODS: Sixty-one TBI survivors completed a background information questionnaire, the BAFQ, and an employment status rating scale. RESULTS: A factor analysis of the BAFQ sub-scales revealed two factors, one related to functioning in the orbitofrontal area, and one related to dorsolateral frontal lobe functioning. These two factors, along with background information, were entered into a discriminant function analysis, revealing a 77.4% accuracy rate in predicting occupational status post-injury. CONCLUSIONS: Demographic variables were found to differentiate employed from unemployed survivors. The BAFQ appeared useful in differentiating survivors who may return to their pre-injury employment level from those who may require modified employment.

Adolescent↗
PubMed2003

The adaptive response of Escherichia coli O157 in an environment with changing pH.

AIMS: To predict and validate survival of non-acid adapted Escherichia coli O157 in an environment mimicking the human stomach. METHODS AND RESULTS: Survival was predicted mathematically from inactivation rates at various, but constant pH values. Predictions were subsequently validated experimentally in a pH-controlled fermentor. Contrary to prediction, acid-sensitive cultures of E. coli O157 survived for a long period of time and died as rapidly as acid-resistant cultures. Experimental results showed that in an environment with changing pH, acid-sensitive cultures became acid-resistant within 17 min. Cyclo fatty acids was reported to be a factor in acid resistance. As synthesis of cyclo fatty acids does not require de novo enzyme synthesis and thus requires little time to develop, we analysed the membrane fatty acid composition of E. coli O157 during adaptation. No changes in membrane fatty acid composition were observed. CONCLUSIONS: Acid adaptation of E. coli O157 can occur during passage of the human gastric acid barrier, which can take up to 4 h. SIGNIFICANCE AND IMPACT OF THE STUDY: The ability of acid-adapted bacteria to survive the human stomach is an important virulence factor. The ability of non-acid adapted E. coli O157 to adapt within a very short period of time under extreme conditions further contributes to the virulence of E. coli O157.

Adaptation, Physiological↗
PubMed2005

Cognitive ability predicts degree of genetic abnormality in participants with 18q deletions.

One of the most common chromosomal deletions is a loss of genetic material from the long arm of chromosome 18. Most individuals with this condition exhibit mental retardation (68%), yet previous attempts to link cognitive status to deletion size have not shown an association, possibly because cases with additional genetic abnormalities were included. We studied 46 participants ranging from 3 to 35 years of age who had a pure genetic abnormality by excluding those with mosaicism or complex genetic rearrangements. Our patients had terminal deletions ranging from a proximal breakpoint at 18q21.1 (greater genetic abnormality, larger deletion size) to a more distal breakpoint at 18q23 characterized with molecular genetic techniques. Cognitive ability, assessed with the age-appropriate measure (Bayley, 1993 , Differential Ability Scale, Wechsler Scales), ranged from IQ = 49 to 113, with a predominance of mild and moderate mental retardation. Using multivariate regression, deletion size breakpoint rank order was predicted by cognitive ability, age, and adaptive behavior (Vineland Adaptive Behavior Scales), accounting for 36% of the variance in deletion size. However, lower cognitive ability (beta = .34, p = .032) and younger age (beta = .296, p = .024) predicted a larger deletion size, but adaptive behavior (beta = .225, p = .15) did not. An additional multivariate regression showed that cognitive ability and age together accounted for 33% of the variance in deletion size, whereas univariate regression showed that cognitive ability accounted for 26% of the variance and age accounted for 11% of the variance. These findings suggest that degree of cognitive impairment is associated with genetic abnormality when a large sample of individuals with "pure" deletions of genetic material from chromosome 18 is examined.

Adaptation, Psychological↗
PubMed2011

Adaptation to climate across the Arabidopsis thaliana genome.

Understanding the genetic bases and modes of adaptation to current climatic conditions is essential to accurately predict responses to future environmental change. We conducted a genome-wide scan to identify climate-adaptive genetic loci and pathways in the plant Arabidopsis thaliana. Amino acid-changing variants were significantly enriched among the loci strongly correlated with climate, suggesting that our scan effectively detects adaptive alleles. Moreover, from our results, we successfully predicted relative fitness among a set of geographically diverse A. thaliana accessions when grown together in a common environment. Our results provide a set of candidates for dissecting the molecular bases of climate adaptations, as well as insights about the prevalence of selective sweeps, which has implications for predicting the rate of adaptation.

Acclimatization↗
PubMed2006

New molecular markers in resistant B-CLL.

B-chronic lymphocytic leukemia (B-CLL) is characterized by a highly variable clinical course which has long remained a stumbling block for clinicians. This variability appears to arise from complex molecular alterations identified in malignant cells from patient subsets. Recent studies have focused in particular on identifying new molecular markers to help predict the most effective and adapted treatments. In addition to the mutation status of immunoglobulin variable heavy-chain region (IgVH) genes, which is a well-established predictive factor in B-CLL, these new markers include defects of cell factors involved in the maintenance of genome stability, such as telomere function, DNA repair, ATM and p53. Other predictive factors, such as tyrosine kinase Zap-70 and soluble factors found in patient sera, may be associated with B-cell receptor signal transduction. Interestingly, an alteration of these factors fits closely, though not strikingly, with the absence of somatic mutations in IgVH genes, suggesting that the latter may be due either to epigenetic events leading to an unstable genome or to an inherited defect in the immune response of malignant B-cells. Recent lessons from Zap-70 expression/phosphorylation suggest that some of these markers may reflect the defective pathways in B-CLL cells rather than being markers of cell malignancy per se. Furthermore, specific subsets of markers are found in patient cells resistant to treatment. Current studies on gene expression profiling and proteomic analyses should soon lead to a better understanding of how these pathways are affected, especially in multi-drug resistant B-CLL.

Biomarkers↗
PubMed2006

Audit of morbidity and mortality following neck of femur fracture using the POSSUM scoring system.

AIMS: The aims of this study were to compare the morbidity and mortality data for patients undergoing surgical fixation of a fractured neck of femur (during a 6-month period) to the predicted morbidity and mortality rates obtained from the POSSUM (Physiological and Operative Severity Score for the enUmeration of Morbidity and Mortality) scoring system, adapted for orthopaedic patients. The predictive accuracy of the orthopaedic POSSUM system is evaluated for this population. The 1-year mortality for the males and females of the study group (mean ages) is compared to the 1-year mortality of male and female New Zealanders of the same age. METHODS: Physiological and operative data was collected from patient notes; patient morbidity and mortality were obtained at 30 days and at 1 year postoperatively. The data were analysed with the orthopaedic POSSUM scoring system. RESULTS: 225 complete datasets were obtained. The mean age of the patients was 83 years; 75% were female. The observed 30-day morbidity and mortality rates were 58% and 12% respectively. The observed 1-year mortality was 38% for males (mean age 79 years) and 29% for females (mean age 84 years). New Zealand census data predicts 7% and 6.4% mortality respectively based on these mean ages. CONCLUSIONS: The POSSUM system allocates patients into groups of varying risk. The observed data shows higher numbers of complications, including death, in patients allocated into higher risk groups. The 1-year mortality is much higher than that predicted based on mean patient age from the New Zealand abridged life table.

Age Distribution↗
PubMed1987

The adaptive significance of sexuality.

The theory predicts that inbred strains of mice are susceptible to tumor viruses that have escaped immune recognition. The theory implies routine evolutionary extinction of asexual species and that existing parthenogenetic species would have to have evolved recently from sexually reproducing precursors. This could be tested by determining the amount of DNA divergence between parthenogenetic and related sexually reproducing species. In mammals and birds genetic substitutions occur at comparable rates, but the AIDS virus evolves about 10 million times more rapidly. This confirms the basic imbalance of rates of evolution between microparasites and metazoan hosts, which is fundamental to the theory. The organization of most eukaryotic genes into exons and introns facilitates the generation of variety of gene products, and the molecular mechanism is similar to the mechanism that generates antibody diversity in the immune response and antigenic variation in trypanosomes. It has been proposed that noncoding 'selfish' DNA is the ultimate sexually transmitted disease. If this were the case, then asexually reproducing species would have an added advantage. An alternative hypothesis is proposed: noncoding DNA could provide insertion sites for retroviruses that would prevent them from being transcribed and replicated and thus moderate their proliferation much as absorber rods moderate proliferation of neutrons in a nuclear reactor. Flowering plants have pollen selection mechanisms that enforce heterozygosity at one or more loci. It has been proposed that analogous sperm selection mechanisms exist in mammals. Such a process would account for observation of a mysterious excess molecular divergence between different strains of inbred mice.

Adaptation, Physiological↗
PubMed2006

Generalized perceptual linear prediction features for animal vocalization analysis.

A new feature extraction model, generalized perceptual linear prediction (gPLP), is developed to calculate a set of perceptually relevant features for digital signal analysis of animal vocalizations. The gPLP model is a generalized adaptation of the perceptual linear prediction model, popular in human speech processing, which incorporates perceptual information such as frequency warping and equal loudness normalization into the feature extraction process. Since such perceptual information is available for a number of animal species, this new approach integrates that information into a generalized model to extract perceptually relevant features for a particular species. To illustrate, qualitative and quantitative comparisons are made between the species-specific model, generalized perceptual linear prediction (gPLP), and the original PLP model using a set of vocalizations collected from captive African elephants (Loxodonta africana) and wild beluga whales (Delphinapterus leucas). The models that incorporate perceptional information outperform the original human-based models in both visualization and classification tasks.

Acoustics↗
PubMed2006

Long-term outcome of social skills intervention based on interactive LEGO play.

LEGO building materials have been adapted as a therapeutic modality for increasing motivation to participate in social skills intervention, and providing a medium through which children with social and communication handicaps can effectively interact. A 3 year retrospective study of long-term outcome for autistic spectrum children participating in LEGO therapy (N = 60) compared Vineland Adaptive Behavior Scale socialization domain (VABS-SD) and Gilliam Autism Rating Scale social interaction subscale (GARS-SI) scores preand post-treatment with a matched comparison sample (N = 57) who received comparable non-LEGO therapy. Although both groups made significant gains on the two outcome measures, LEGO participants improved significantly more than the comparison subjects. Diagnosis and pre-treatment full-scale IQ scores did not predict outcome scores; however, Vineland adaptive behavior composite, Vineland communication domain, and verbal IQ all predicted outcome on the VABS-SD, especially for the LEGO therapy group. Results are discussed in terms of implications for methods of social skills intervention for autistic spectrum disorders.

Antipsychotic Agents↗