Individual Changes (individual + change)

Distribution by Scientific Domains


Selected Abstracts


Density-dependent reproduction in the European rabbit: a consequence of individual response and age-dependent reproductive performance

OIKOS, Issue 3 2004
Heiko G. Rödel
Density dependence of reproduction has generally been proposed to be caused by habitat heterogeneity and by the individual response of reproductive output. However, a further mechanism might generate density dependence of average reproductive rates. High density situations might be associated with a high proportion of first-season breeders which often show a principally lower reproductive performance. We tested for the existence of the latter mechanism as well as for density-dependent individual changes of reproductive effort in a population of European rabbits living in a homogeneous grassland habitat. The study was conducted over a period of eleven years. Overall, a strong relationship between mean reproductive rates and the breeding density of females was apparent. All necessary conditions for the presence of a density-dependent effect caused by age-dependent reproduction were fulfilled: Fluctuations of breeding density were paralleled by variations in the proportion of one-year-old females. These one-year-old, first-season breeders showed a consistently lower reproductive performance than older females, which might be caused by their lower body mass and their lower social rank. However, we also found strong evidence for density-dependent response of individual reproductive effort: Individual changes in fecundity over successive years were explained by changes in the breeding density of females. The results suggest that density dependence of reproduction in European rabbits is due to an interaction of age-dependent reproductive performance together with short-term fluctuations in breeding density, and a density-dependent, individual based response of reproductive rates. We further conclude that the lower reproductive performance of first-season breeders in age-structured animal populations may contribute substantially to interannual, and under particular circumstances to density-dependent variations of mean reproductive rates. [source]


Use of GPS/MET refraction angles in three-dimensional variational analysis

THE QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY, Issue 570 2000
X. Zou
Abstract The Spectral Statistical Interpolation (SSI) analysis system of the National Centers for Environmental Prediction (NCEP) is modified to include GPS/MET data (meteorological data from the Global Positioning Satellite system) using a GPS ray-tracing operator. The new system is tested by incorporating 30 actual GPS/MET observations of refraction angles obtained during the GPS/MET experiment. This is the first time that real radio occupation refraction angles and refractivities have been incorporated into a three-dimensional variational analysis system. We examine the magnitude and the vertical distribution of the analysis adjustments that result from using refraction-angle observations in the NCEP SSI analysis system. The average magnitudes of the adjustments in the temperature and specific-humidity fields are approximately 0.4 degC and 0.6 g kg,1, respectively. Individual changes can be as large as 4 degC and 4g kg,1, respectively. The greatest adjustments to the temperature occur in the middle and upper troposphere and stratosphere, while the major changes in specific humidity occur in the lower troposphere. An assessment of the impact of the GPS/MET observations on the analysis, verified by conventional (mostly radiosonde) data, is difficult because of the small number of GPS/MET data used. Nevertheless, it is found that, even over data-rich regions (regions containing many radiosonde observations), and even when the verification data were the radiosonde data themselves, the use of GPS/MET refraction angles makes a slight improvement, overall, to the analysed temperatures and winds. The impact on the water-vapour analyses, again as measured against radiosonde data, is mixed, with improvements shown in some layers and degradation in others. Compared with the background field, the use of refraction angles from one occultation results in an analysis whose simulated refraction angles are much closer to the withheld GPS/MET refraction angles at the two nearby occultation locations, and whose temperature and moisture profiles are also closer to those resulting from the direct assimilation of the two withheld occultations. Although the forward model used in this study, with the ray tracing being carried out in a two-dimensional plane, is much cheaper than a more accurate three-dimensional forward model, it is still quite expensive. In order to further reduce the computational requirement for the assimilation of GPS/MET data, we test a scheme in which the GPS/MET-retrieved refractivities (instead of refraction angles) are used above a selected height for each occupation. These heights are determined objectively based on the departures from spherical symmetry of the model field. It is shown that the mixed use of GPS/MET refraction angles and refractivities produces an analysis result similar to the one using refraction angles alone, while the computational cost is reduced by more than 30%. [source]


A 2-year follow-up of 233 very mild (CDR 0.5) Alzheimer's disease patients (REAL. FR cohort)

INTERNATIONAL JOURNAL OF GERIATRIC PSYCHIATRY, Issue 5 2008
Fati Nourhashémi
Abstract Objectives Making an early diagnosis of Alzheimer's Disease (AD) is becoming increasingly important. The Clinical Dementia Rating scale (CDR), a semi-structured interview with patient and caregiver, is a global rating scale designed for use in staging dementia. The primary objective of our study was to examine the evolution of AD in individuals with very mild AD (CDR 0.5) across a 2-year follow up. Methods A cohort of AD patients (n,=,682) living in the community were followed during 2 years in 16 centres of the French AD network. Each subject underwent extensive medical examination including the MMSE and CDR every 6 months. Results Two hundred and thirty-three AD patients were rated CDR 0.5 at baseline (mean MMSE score: 23.15,±,2.57). They were younger and reported an average duration of symptoms of approximately 0.8 years less than patients with CDR,,,1. During the 2-year follow-up, none of the AD CDR 0.5 subjects improved; 65% of them showed an increase in the CDR score. The rate of cognitive decline was similar between the AD CDR 0.5 and CDR,,,1 groups. The ADL decline was more significant in patients with CDR,,,1 at inclusion. Conclusions It is certainly possible to identify AD at a very early stage focusing on intra individual change in cognitive and functional impairment. Criteria with a high sensitivity and specificity for detecting AD at an early stage will help to further develop effective pharmacological and behavioural interventions for delaying the onset and progression of the disease. Copyright © 2007 John Wiley & Sons, Ltd. [source]


Meaningful Change and Responsiveness in Common Physical Performance Measures in Older Adults

JOURNAL OF AMERICAN GERIATRICS SOCIETY, Issue 5 2006
Subashan Perera PhD
OBJECTIVES: To estimate the magnitude of small meaningful and substantial individual change in physical performance measures and evaluate their responsiveness. DESIGN: Secondary data analyses using distribution- and anchor-based methods to determine meaningful change. SETTING: Secondary analysis of data from an observational study and clinical trials of community-dwelling older people and subacute stroke survivors. PARTICIPANTS: Older adults with mobility disabilities in a strength training trial (n=100), subacute stroke survivors in an intervention trial (n=100), and a prospective cohort of community-dwelling older people (n=492). MEASUREMENTS: Gait speed, Short Physical Performance Battery (SPPB), 6-minute-walk distance (6MWD), and self-reported mobility. RESULTS: Most small meaningful change estimates ranged from 0.04 to 0.06 m/s for gait speed, 0.27 to 0.55 points for SPPB, and 19 to 22 m for 6MWD. Most substantial change estimates ranged from 0.08 to 0.14 m/s for gait speed, 0.99 to 1.34 points for SPPB, and 47 to 49 m for 6MWD. Based on responsiveness indices, per-group sample sizes for clinical trials ranged from 13 to 42 for substantial change and 71 to 161 for small meaningful change. CONCLUSION: Best initial estimates of small meaningful change are near 0.05 m/s for gait speed, 0.5 points for SPPB, and 20 m for 6MWD and of substantial change are near 0.10 m/s for gait speed, 1.0 point for SPPB, and 50 m for 6MWD. For clinical use, substantial change in these measures and small change in gait speed and 6MWD, but not SPPB, are detectable. For research use, these measures yield feasible sample sizes for detecting meaningful change. [source]


Stability and individual change in depressive symptoms among mothers raising young children with ASD: maternal and child correlates,

JOURNAL OF CLINICAL PSYCHOLOGY, Issue 12 2009
Alice S. Carter
Abstract Mothers raising children with Autism Spectrum Disorders (ASD) evidence elevated depressive symptoms, but symptom stability has not been examined. Mothers (N=143) of toddlers with ASD (77% boys) were enrolled and assessed when their children were 18 to 33 months old and followed annually for 2 years. Multilevel modeling revealed no significant change in group depressive symptom level, which was in the moderately elevated range (Intercept=13.67; SE=.96). In contrast, there was significant individual variation in change over time. Child problem behaviors and delayed competence, maternal anxiety symptoms and angry/hostile mood, low parenting efficacy and social supports, and coping styles were associated with depression severity. Only maternal anxiety and parenting efficacy predicted individual change. Many mothers do not appear to adapt, supporting the need for early intervention for maternal well-being. © 2009 Wiley Periodicals, Inc. J Clin Psychol 65: 1,11, 2009. [source]


Beyond Therapy: Problem-Solving Courts and the Deliberative Democratic State

LAW & SOCIAL INQUIRY, Issue 4 2008
Rekha Mirchandani
Problem-solving courts (drug courts, community courts, domestic violence courts, and mental health courts), unlike traditional courts, attempt to get at the root of the individual and social problems that motivate criminal behavior. Theoretical understandings of problem-solving courts are mostly Foucauldian; proponents argue that these new institutions employ therapeutic techniques that encourage individuals to self-engineer in ways that subtly increase state power. The Foucauldian approach captures only some elements of problem-solving courts and does not fully theorize the revolution in justice that these courts present. Problem-solving courts, domestic violence courts in particular, orient not just around individual change but also around social change and cultural transformation. Combining the Foucauldian idea of a therapeutic state (as developed by James Nolan) with an understanding of the deliberative democratic mechanisms of larger-scale structural transformation (found in Habermas and others) leads to a more balanced and empirically open orientation to the actual motivations, goals, and achievements of problem-solving courts. [source]


Problem-based learning: why curricula are likely to show little effect on knowledge and clinical skills

MEDICAL EDUCATION, Issue 9 2000
Mark Albanese
Objectives A recent review of problem-based learning's effect on knowledge and clinical skills updated findings reported in 1993. The author argues that effect sizes (ES) seen with PBL have not lived up to expectations (0.8,1.0) and the theoretical basis for PBL, contextual learning theory, is weak. The purposes of this study were to analyse what constitutes reasonable ES in terms of the impacts on individuals and published reports, and to elaborate upon various theories pertaining to PBL. Design Normal theory is used to demonstrate what various ESs would mean for individual change and a large meta-analysis of over 10 000 studies is referred to in identifying typical ESs. Additional theories bearing upon PBL are presented. Results Effect sizes of 0.8,1.0 would require some students to move from the bottom quartile to the top half of the class or more. The average ES reported in the literature was 0.50 and many commonly used and accepted medical procedures and therapies are based upon studies with ESs below 0.50. Conclusions Effect sizes of 0.8,1.0 are an unreasonable expectation from PBL because, firstly, the degree of changes that would be required of individuals would be excessive, secondly, leading up to medical school, students are groomed and selected for success in a traditional curriculum, expecting them to do better in a PBL curriculum than a traditional curriculum is an unreasonable expectation, and, thirdly, the average study reported in the literature and many commonly used and accepted medical procedures and therapies are based upon studies having lesser ESs. Information-processing theory, Cooperative learning, Self-determination theory and Control theory are suggested as providing better theoretical support for PBL than Contextual learning theory. Even if knowledge acquisition and clinical skills are not improved by PBL, the enhanced work environment for students and faculty that has been consistently found with PBL is a worthwhile goal. [source]


Costly carotenoids: a trade-off between predation and infection risk?

JOURNAL OF EVOLUTIONARY BIOLOGY, Issue 4 2005
I. T. VAN DER VEEN
Abstract Carotenoid reserves in copepods seem costly in terms of predation risk because they make individuals conspicuous. However, carotenoids also seem to play an important role in immune defence as free radical scavengers. To test whether predation risk influences carotenoid levels and whether changes in carotenoid levels are related to changes in immune defence, I examined individual changes in large carotenoid and other lipid droplets upon exposure to predation risk and subsequent exposure to parasites in the copepod Macrocyclops albidus. Copepods reduced carotenoid reserves upon exposure to predators, through which they potentially avoided the costs of being conspicuous under predation risk. Thus, the size of carotenoid reserves is a plastic trait. Such a decrease in carotenoid reserves may also have a negative impact on the copepods' immune system as individuals that decreased their reserves suffered higher parasite prevalence upon exposure to the cestode Schistocephalus solidus. These results suggest that carotenoid reserves may be individually optimized to trade-off each individual's unique costs (predation risk) and benefits (immune defence) of having these reserves. [source]


Changes in Sensation Seeking and Risk-Taking Propensity Predict Increases in Alcohol Use Among Early Adolescents

ALCOHOLISM, Issue 8 2010
Laura MacPherson
Background:, Conceptual models implicating disinhibitory traits often are applied to understanding emergent alcohol use, but, little is known of how inter-individual changes in these constructs relate to increases in alcohol use in early adolescence. The current study utilized behavioral and self-report instruments to capture the disinhibitory-based constructs of sensation seeking and risk-taking propensity to examine if increases in these constructs over time related to increases in early adolescent alcohol use. Methods:, Participants included a community sample of 257 early adolescents (aged 9 to 12) who completed a self-report measure of sensation seeking, a behavioral task assessing risk-taking propensity, and a self-report of past year alcohol use, at 3 annual assessment waves. Results:, Both sensation seeking and risk-taking propensity demonstrated significant increases over time, with additional evidence that change in the behavioral measure of risk-taking propensity was not because of practice effects. Greater sensation seeking and greater risk-taking propensity demonstrated concurrent relationships with past year alcohol use at each assessment wave. Prospective analyses indicated that after accounting for initial levels of alcohol use, sensation seeking, and risk-taking propensity at the first assessment wave, larger increases in both constructs predicted greater odds of alcohol use at subsequent assessment waves. Conclusions:, Results indicate the role of individual changes in disinhibitory traits in initial alcohol use in early adolescents. Specifically, findings suggest it is not simply initial levels of sensation seeking and risk-taking propensity that contribute to subsequent alcohol use but in particular increases in each of these constructs that predict greater odds of use. Future work should continue to assess the development of sensation seeking and risk-taking propensity in early adolescence and target these constructs in interventions as a potential means to reduce adolescent alcohol use. [source]


Developmental Trajectories of Impulsivity and Their Association With Alcohol Use and Related Outcomes During Emerging and Young Adulthood I

ALCOHOLISM, Issue 8 2010
Andrew K. Littlefield
Background:, Research has documented normative patterns of personality change during emerging and young adulthood that reflect decreases in traits associated with substance use, such as impulsivity. However, evidence suggests variability in these developmental changes. Methods:, This study examined trajectories of impulsivity and their association with substance use and related problems from ages 18 to 35. Analyses were based on data collected from a cohort of college students (N = 489), at high and low risk for AUDs, first assessed as freshmen at a large, public university. Results:, Mixture modeling identified five trajectory groups that differed in baseline levels of impulsivity and developmental patterns of change. Notably, the trajectory group that exhibited the sharpest declines in impulsivity tended to display accelerated decreases in alcohol involvement from ages 18 to 25 compared to the other impulsivity groups. Conclusion:, Findings highlight the developmental nature of impulsivity across emerging and young adulthood and provide an empirical framework to identify key covariates of individual changes of impulsivity. [source]


Understanding software maintenance and evolution by analyzing individual changes: a literature review

JOURNAL OF SOFTWARE MAINTENANCE AND EVOLUTION: RESEARCH AND PRACTICE, Issue 6 2009
Hans Christian Benestad
Abstract Understanding, managing and reducing costs and risks inherent in change are key challenges of software maintenance and evolution, addressed in empirical studies with many different research approaches. Change-based studies analyze data that describes the individual changes made to software systems. This approach can be effective in order to discover cost and risk factors that are hidden at more aggregated levels. However, it is not trivial to derive appropriate measures of individual changes for specific measurement goals. The purpose of this review is to improve change-based studies by (1) summarizing how attributes of changes have been measured to reach specific study goals and (2) describing current achievements and challenges, leading to a guide for future change-based studies. Thirty-four papers conformed to the inclusion criteria. Forty-three attributes of changes were identified, and classified according to a conceptual model developed for the purpose of this classification. The goal of each study was to either characterize the evolution process, to assess causal factors of cost and risk, or to predict costs and risks. Effective accumulation of knowledge across change-based studies requires precise definitions of attributes and measures of change. We recommend that new change-based studies base such definitions on the proposed conceptual model. Copyright © 2009 John Wiley & Sons, Ltd. [source]


Modulation of pPS10 host range by DnaA

MOLECULAR MICROBIOLOGY, Issue 1 2002
Beatriz Maestro
Summary Narrow-host-range plasmid pPS10, originally found in Pseudomonas savastanoi, is unable to replicate in other strains such as Escherichia coli. Here, we report that the establishment of pPS10 in E. coli can be achieved by a triple mutation in the dnaA gene of E. coli (dnaA403), leading to Q14amber, P297S and A412V changes in the DnaA host replication protein (DnaA403 mutant). As the E. coli strain used contained double amber suppressor mutations (supE, supF), the amber codon in dnaA403 can be translated into glutamine or tyrosine. Genetic analysis of DnaA proteins containing either the individual changes or their different combinations suggests that the P297S mutation is crucial for the establishment of the pPS10 replicon in E. coli. The data also indicate that the P297S change is toxic to the cell and that the additional mutations in DnaA403 could contribute to neutralize this toxicity. To our knowledge, this work reports the first chromosome mutant described in the literature that allows the host range broadening of a plasmid, highlights the essential role played by DnaA in the establishment of pPS10 replicon in E. coli and provides support for the hypothesis that interactions between RepA and DnaA modulate the establish-ment of pPS10 in that bacteria and probably in other species. [source]


Density-dependent reproduction in the European rabbit: a consequence of individual response and age-dependent reproductive performance

OIKOS, Issue 3 2004
Heiko G. Rödel
Density dependence of reproduction has generally been proposed to be caused by habitat heterogeneity and by the individual response of reproductive output. However, a further mechanism might generate density dependence of average reproductive rates. High density situations might be associated with a high proportion of first-season breeders which often show a principally lower reproductive performance. We tested for the existence of the latter mechanism as well as for density-dependent individual changes of reproductive effort in a population of European rabbits living in a homogeneous grassland habitat. The study was conducted over a period of eleven years. Overall, a strong relationship between mean reproductive rates and the breeding density of females was apparent. All necessary conditions for the presence of a density-dependent effect caused by age-dependent reproduction were fulfilled: Fluctuations of breeding density were paralleled by variations in the proportion of one-year-old females. These one-year-old, first-season breeders showed a consistently lower reproductive performance than older females, which might be caused by their lower body mass and their lower social rank. However, we also found strong evidence for density-dependent response of individual reproductive effort: Individual changes in fecundity over successive years were explained by changes in the breeding density of females. The results suggest that density dependence of reproduction in European rabbits is due to an interaction of age-dependent reproductive performance together with short-term fluctuations in breeding density, and a density-dependent, individual based response of reproductive rates. We further conclude that the lower reproductive performance of first-season breeders in age-structured animal populations may contribute substantially to interannual, and under particular circumstances to density-dependent variations of mean reproductive rates. [source]


Contrasting longitudinal and cross-sectional relationships between insulin resistance and percentage of body fat, fitness, and physical activity in children,the LOOK study

PEDIATRIC DIABETES, Issue 8 2009
Richard D Telford
Background: Knowledge of individual changes in insulin resistance (IR) and longitudinal relationships of IR with lifestyle-associated factors are of important practical significance, but little longitudinal data exist in asymptomatic children. We aimed to determine (a) changes in the homeostatic model of insulin resistance (HOMA-IR) over a 2-yr period and (b) comparisons of longitudinal and cross-sectional relationships between HOMA-IR and lifestyle-related risk factors. Methods: Our subjects, 241 boys and 257 girls, were assessed at age 8.1 yr (SD 0.35) and again 2 yr later for fasting blood glucose and insulin, dual X-ray absorptiometry-assessed percentage of body fat (%BF), pedometer-assessed physical activity (PA), and cardio-respiratory fitness (CRF) by multistage running test. Results: HOMA-IR was initially 9% greater in girls than boys and 27% greater 2 yr later. There was no evidence of longitudinal relationships between HOMA-IR and %BF in boys or girls, despite significant cross-sectional relationships (p < 0.001). In boys, there was evidence of a longitudinal relationship between HOMA-IR and both PA (p < 0.001) and CRF (p = 0.05). In girls, we found a cross-sectional relationship between HOMA-IR and CRF (p < 0.001). Conclusions: HOMA-IR increases between 8 and 10 yr of age and to a greater extent in girls. Longitudinal, unlike cross-sectional, relationships do not support the premise that body fat has any impact on HOMA-IR during this period or that PA or CRF changes affect HOMA-IR in girls. These data draw attention to difficulties in interpreting observational studies in young children. [source]


A Short Note About Energy-Efficiency Performance of Thermally Coupled Distillation Sequences

THE CANADIAN JOURNAL OF CHEMICAL ENGINEERING, Issue 1 2006
Juan Gabriel Segovia-Hernández
Abstract In this work, we present a comparative study of the energy-efficiency performance between conventional distillation sequences and thermally coupled distillation arrangements (TCDS) for the separation of ternary mixtures of hydrocarbons under the action of feedback control loops. The influence of the relative ease of separation of the feed mixture and its composition was analyzed. The feedback analysis was conducted through servo tests with individual changes in the set points for each of the three product streams. Standard PI controllers were used for each loop. The results show an apparent trend regarding the sequence with a better dynamic performance. Generally, TCDS options performed better for the control of the extreme components of the ternary mixture (A and C), while the conventional sequences offered a better dynamic behaviour for the control of the intermediate component (B). The only case in which there was a dominant structure for all control loops was when the feed contained low amounts of the intermediate component and the mixture had similar relative volatilities. The Petlyuk column provided the optimal choice in such case, which contradicts the general expectations regarding its control behaviour. In addition, the energy demands during the dynamic responses were significantly lower than those observed for the other distillation sequences. TCDS options, therefore, are not only more energy efficient than the conventional sequences, but there are cases in which they also offer better feedback control properties. On présente dans ce travail une étude comparative de la performance d'efficacité d'énergétique entre les séquences de distillation conventionnelles et les configurations de distillation couplées thermiquement (TCDS) pour la séparation de mélanges ternaires d'hydrocarbures sous l'action de boucles de contrôle d'asservissement. L'influence de la facilité relative de séparation du mélange d'alimentation et de sa composition est analysée. L'analyse de rétroalimentation est réalisée grâce à des tests d'asservissement avec des changements individuels dans les points de consigne pour chacun des trois courants de produits. Des contrôleurs PI standards ont été utilisés pour chaque boucle. Les résultats montrent une tendance apparente pour la séquence ayant une meilleure performance dynamique. Généralement, les options TCDS sont meilleures pour le contrôle des composantes extrêmes du mélange ternaire (A et C), tandis que les séquences conventionnelles offrent un meilleur contrôle dynamique pour le contrôle de la composante intermédiaire (B). Le seul cas où il y a une structure dominante pour toutes les boucles de contrôle, c'est lorsque l'alimentation contenant de faibles quantités de la composante intermédiaire et le mélange ont la même volatilité relative. La colonne Petlyuk est le choix optimal dans un tel cas, ce qui contredit les attentes générales concernant son comportement de contrôle. En outre, les demandes d'énergie pendant les réponses dynamiques sont significativement plus faibles que celles observées pour les autres séquences de distillation. Ainsi, non seulement les options TCDS sont plus efficaces que les séquences conventionnelles, mais il y a des cas où elles offrent également de meilleures propriétés de contrôle d'asservissement. [source]


Population pharmacokinetic modelling of gentamicin and vancomycin in patients with unstable renal function following cardiothoracic surgery

BRITISH JOURNAL OF CLINICAL PHARMACOLOGY, Issue 2 2006
Christine E. Staatz
Aims To describe the population pharmacokinetics of gentamicin and vancomycin in cardiothoracic surgery patients with unstable renal function. Methods Data collected during routine care were analyzed using NONMEM. Linear relationships between creatinine clearance (CLCr) and drug clearance (CL) were identified, and two approaches to modelling changing CLCr were examined. The first included baseline (BCOV) and difference from baseline (DCOV) effects and the second allowed the influence of CLCr to vary between individuals. Final model predictive performance was evaluated using independent data. The data sets were then combined and parameters re-estimated. Results Model building was performed using data from 96 (gentamicin) and 102 (vancomycin) patients, aged 17,87 years. CLCr ranged from 9 to 172 ml min,1 and changes varied from ,76 to 58 ml min,1 (gentamicin) and ,86 to 93 ml min,1 (vancomycin). Inclusion of BCOV and DCOV improved the fit of the gentamicin data but had little effect on that for vancomycin. Inclusion of interindividual variability (IIV) in the influence of CLcr resulted in a poorly characterized model for gentamicin and had no effect on vancomycin modelling. No bias was seen in population compared with individual CL estimates in independent data from 39 (gentamicin) and 37 (vancomycin) patients. Mean (95% CI) differences were 4% (,3, 11%) and 2% (,2, 6%), respectively. Final estimates were: CLGent (l h,1) = 2.81 × (1 + 0.015 × (BCOVCLCr -BCOVCLCr,Median) + 0.0174 × DCOVCLCr); CLVanc (l h,1) = 2.97 × (1 + 0.0205 ×, (CLCr -CLCr,Median)). IIV in CL was 27% for both drugs. Conclusions A parameter describing individual changes in CLcr with time improves population pharmacokinetic modelling of gentamicin but not vancomycin in clinically unstable patients. [source]


A new genetic algorithm with diploid chromosomes using probability decoding for adaptation to various environments

ELECTRONICS & COMMUNICATIONS IN JAPAN, Issue 8 2010
Manabu Kominami
Abstract This paper proposes a new diploid operation technique using probability for function optimization in nonstationary environments and describes a feature of diploid genetic algorithms (GAs). The advantage of the technique over previous diploid GAs is that one genotype is transformed into many phenotypes based on probability. This transformation is not made at random. It has a certain range of probabilities. Each individual has a range. The range allows adaptation to various environments. The technique allows genes to give a probabilistic representation of dominance, and can maintain the diversity of individuals. The experimental results show that the technique can adapt to severe environmental changes where previous diploid GAs cannot adapt. This paper shows that the technique can find optimum solutions with high probability and that the distribution of individuals changes when the environment changes. In addition, by comparing the proposed diploid GA with a haploid GA whose chromosome is twice the length, the features of the diploid are described. © 2010 Wiley Periodicals, Inc. Electron Comm Jpn, 93(8): 38,46, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecj.10097 [source]