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PubMed1992

Changing-loudness aftereffect following simulated movement: implications for channel hypotheses concerning sound level change and movement.

Listening to a tone changing unidirectionally in sound level causes an illusion of changing loudness in a steady tone afterward. This aftereffect may indicate channels for detecting the feature of change in sound level, which would primarily concern dynamic sound localization. Three subjects, one of whom was the author, participated in this study. The author predicted that opposite adaptation of the ears (the adapting stimulus is heard to move from one ear to the other) should lead to a movement aftereffect. This was not reported by the subjects. However, the subjects did report a changing-loudness aftereffect in a monaural test stimulus, and the characteristics of the changing-loudness aftereffect (such as its magnitude) were consistent with previous data, suggesting a two-stage channel hypothesis: Output from channels for several features, including sound-level change, simultaneously stimulate movement channels.

Attention↗
PubMed2002

Comparative studies of evolutionary responses to light environments in Arabidopsis.

In this article, we compare the reaction norms to foliage shade (changes in light quality, spatially fine-grained environmental variation) and photoperiod (day length, spatially coarse-grained environmental variation) in several haplotypes of Arabidopsis thaliana from Scandinavia. We found that both across-environment means and phenotypic plasticities evolved continuously and very rapidly within this group. Both character means and trait plasticities were highly integrated, in part as predicted by the adaptive plasticity hypothesis for response to foliage shade (the so-called shade-avoidance syndrome). We found that a significant but small fraction of the variance in across-treatment trait means and plasticities in response to one environmental factor is explained by variation of the same traits in response to the other factor. Genetic relatedness based on chloroplast DNA sequence variation among haplotypes was not associated with variation in across-treatment character means or their plasticities, suggesting that evolution of these characters has occurred on a local geographic scale via reticulation (outcrossing) among maternal lines rather than by the differential survival of selfing lineages.

Adaptation, Physiological↗
PubMed1995

Fear and fearfulness in animals.

Persistence of individual differences in animal behavior in reactions to various environmental challenges could reflect basic divergences in temperament, which might be used to predict details of adaptive response. Although studies have been carried out on fear and anxiety in various species, including laboratory, domestic and wild animals, no consistent definition of fearfulness as a basic trait of temperament has emerged. After a classification of the events that may produce a state of fear, this article describes the great variability in behavior and in physiological patterns generally associated with emotional reactivity. The difficulties of proposing fearfulness--the general capacity to react to a variety of potentially threatening situations--as a valid basic internal variable are then discussed. Although there are many studies showing covariation among the psychobiological responses to different environmental challenges, other studies find no such correlations and raise doubts about the interpretation of fearfulness as a basic personality trait. After a critical assessment of methodologies used in fear and anxiety studies, it is suggested that discrepancies among results are mainly due to the modulation of emotional responses in animals, which depend on numerous genetic and epigenetic factors. It is difficult to compare results obtained by different methods from animals reared under various conditions and with different genetic origins. The concept of fearfulness as an inner trait is best supported by two kinds of investigations. First, an experimental approach combining ethology and experimental psychology produces undeniable indicators of emotional reactivity. Second, genetic lines selected for psychobiological traits prove useful in establishing relationships between behavioral and neuroendocrine aspects of emotional reactivity. It is suggested that fearfulness could be considered a basic feature of the temperament of each individual, one that predisposes it to respond similarly to a variety of potentially alarming challenges, but is nevertheless continually modulated during development by the interaction of genetic traits of reactivity with environmental factors, particularly in the juvenile period. Such interaction may explain much of the interindividual variability observed in adaptive responses.

Animals↗
PubMed2002

Antioxidant gene expression in active and sedentary house mice (Mus domesticus) selected for high voluntary wheel-running behavior.

We present liver mRNA levels of the two antioxidant enzymes catalase (CAT) and Mn-superoxide dismutase (SOD2) in four treatment groups of house mice assayed by RNase protection at 20 months of age. These groups were mice from four replicate selection and four replicate control lines from the sixteenth generation of selective breeding for high voluntary wheel running, housed with or without running wheels from age 3 weeks through 20 months. Exercising control females had induced CAT expression; SOD2 exhibited a similar pattern in females from two of the four control lines. Exercising male mice had induced CAT expression, but not SOD2 expression, irrespective of genetic background. We discuss these results with respect to both evolutionary (genetic) and training (exercise-induced) adaptations and explore predictions of these results in relation to the oxidative-damage theory of senescence.

Aging↗
PubMed2006

The potential for bone loss in acetabular structures following THA.

Attempts to preserve periacetabular bone stock following total hip replacement have largely ignored the potential for stress shielding in the acetabulum. We sought to quantify the change in stress distribution in acetabular bone with components of varying material stiffness by developing a high-resolution 3-D finite element model from CT scans of a young female donor. Periprosthetic bone stresses and strains on the left pelvis were compared with hemispherical cups of various material properties and with a horseshoe shaped polymeric design described in the recent literature. We observed unphysiologic periacetabular bone stress and strain fields for all designs tested. For hemispherical components, reduction of the acetabular shell material modulus caused modest changes in bone stress compared to the changes in implant geometry. The horseshoe shaped cup more effectively loaded the acetabular structures than the hemispherical design. Our results suggest stress and strain fields in pelvic structures after introduction of hemispherical acetabular components predict inevitable bone adaptation that can not be resolved by changes in implant material properties alone. Radical changes in implant design may be necessary for long-term maintenance of supporting structures in the reconstructed acetabulum.

Acetabulum↗
PubMed1994

An adaptive plasma glucose controller based on a nonlinear insulin/glucose model.

The design of plasma glucose controllers traditionally relies on linear approaches. The implementation of an appropriate nonlinear model of the insulin/glucose regulatory system into an adaptive controller should predict the insulin-dependent glucose removal more reliably and hence provide better control over a wide spectrum of insulin signals. A discretized form of the model leads to a two-step procedure. First, the measured plasma glucose levels associated with the exogenous glucose infusion rates are used in the estimation of the past removal rates which, in turn, can be expressed as a weighted sum of past insulin inputs and previous values of the removal rate. Parameters of the sum are adjusted on-line by a recursive method of estimation which features a prefiltering of data to account for a corrupting coloured process noise. The same equation is in turn used to predict the time course of the insulin-dependent fractional rate of glucose removal. The performance of the controller, tested in vivo in three pigs, is presented for various intravenous or subcutaneous rapid injections and staircase infusions of insulin. Plasma glucose is maintained at an average level of 99.9 +/- 8.7% of the target value (% set point +/- coefficient of variation). The controller reacts promptly to large and rapid variations in insulin action. Although control improves with the number of glucose measurements, the prediction of glucose removal allows for some flexibility in the monitoring of the plasma glucose. Sampling frequency varied from a 2 min interval during transient periods to 7 min as steady states were reached.

Algorithms↗
PubMed2006

Phenotypic plasticity in two marine snails: constraints superseding life history.

In organisms encountering predictable environments, fixed development is expected, whereas in organisms that cannot predict their future environment, phenotypic plasticity would be optimal to increase local adaptation. To test this prediction we experimentally compared phenotypic plasticity in two rocky-shore snail species; Littorina saxatilis releasing miniature snails on the shore, and Littorina littorea releasing drifting larvae settling on various shores, expecting L. littorea to show more phenotypic plasticity than L. saxatilis. We compared magnitude and direction of vectors of phenotypic difference in juvenile shell traits after 3 months exposure to different stimuli simulating sheltered and crab-rich shores, or wave-exposed and crab-free shores. Both species showed similar direction and magnitude of vectors of phenotypic difference with minor differences only between ecotypes of the nondispersing species, indicating that plasticity is an evolving trait in L. saxatilis. The lack of a strong plastic response in L. littorea might be explained by limits rather than costs to plasticity.

Animals↗
PubMedDate not supplied

From cells to colonies: at what levels of body organization does the 'temperature-size rule' apply?

An inverse relationship between temperature during ontogeny and final body size is widespread in ectotherms, but poorly understood. Evidence suggests that within organs, this "temperature-size rule" (TSR) may also apply to cell size with no change in numbers. So how closely do reductions in size and number of cells and other repeated structures correlate with size reduction at higher levels of organization? We examine this in the context of a proposal that size and/or number changes at various organizational levels are adaptive responses to temperature- and size-dependent oxygen supply. We subjected two clones of the modular colonial bryozoan, Celleporella hyalina, to orthogonal combinations of two temperatures and two oxygen concentrations during ontogeny, observing effects on sizes of colonies and larvae, and sizes and numbers of cells, tentacles, and modules (autozooids). We found that the size:number responses varied among cell types and among structures at different levels of organization, with the inverse temperature-size relationship applying only to larval parenchymal cells and colony modules. Using our findings and other evidence we propose a unifying adaptive hypothesis that predicts how temperature affects the sizes of mitochondria, cells, organs, modules and organisms, and their relationships with processes that determine the functional capacity of aerobic metabolism.

Animals↗
PubMed1992

Sexually antagonistic genes: experimental evidence.

When selection differs between the sexes, a mutation beneficial to one sex may be harmful to the other (sexually antagonistic). Because the sexes share a common gene pool, selection in one sex can interfere with the other's adaptive evolution. Theory predicts that sexually antagonistic mutations should accumulate in tight linkage with a new sex-determining gene, even when the harm to benefit ratio is high. Genetic markers and artificial selection were used to make a pair of autosomal genes segregate like a new pair of sex-determining genes in a Drosophila melanogaster model system. A 29-generation study provides experimental evidence that sexually antagonistic genes may be common in nature and will accumulate in response to a new sex-determining gene.

Animals↗
PubMed2003

Probing the role of divalent metal ions in a bacterial psychrophilic metalloprotease: binding studies of an enzyme in the crystalline state by x-ray crystallography.

The psychrophilic alkaline metalloprotease (PAP) produced by a Pseudomonas bacterium isolated in Antarctica belongs to the clan of metzincins, for which a zinc ion is essential for catalytic activity. Binding studies in the crystalline state have been performed by X-ray crystallography in order to improve the understanding of the role of the zinc and calcium ions bound to this protease. Cocrystallization and soaking experiments with EDTA in a concentration range from 1 to 85 mM have resulted in five three-dimensional structures with a distinct number of metal ions occupying the ion-binding sites. Evolution of the structural changes observed in the vicinity of each cation-binding site has been studied as a function of the concentration of EDTA, as well as of time, in the presence of the chelator. Among others, we have found that the catalytic zinc ion was the first ion to be chelated, ahead of a weakly bound calcium ion (Ca 700) exclusive to the psychrophilic enzyme. Upon removal of the catalytic zinc ion, the side chains of the active-site residues His-173, His-179 and Tyr-209 shifted approximately 4, 1.0, and 1.6 A, respectively. Our studies confirm and also explain the sensitivity of PAP toward moderate EDTA concentrations and propose distinct roles for the calcium ions. A new crystal form of native PAP validates our previous predictions regarding the adaptation of this enzyme to cold environments as well as the proteolytic domain calcium ion being exclusive for PAP independent of crystallization conditions.

Binding Sites↗
PubMed1983

Sensory and motor conflict in motion sickness.

Motion sickness occurs in a wide variety of circumstances involving real or apparent motion, many of them novel and man-made. Significantly, voluntary body movements rarely result in symptoms, and the likelihood of motion sickness is greatly reduced by having control of the vehicle in which one is riding. The unifying theory of Reason [1978] proposes that motion sickness results when there is a mismatch between predicted and actual sensory inputs. Hence, the less predictable the sensory input (because it results from an externally imposed motion, or from motion which results in errors of neural transduction), the more likely that motion sickness will develop. With continuing exposure, predictability increases and adaptation to motion sickness occurs.

Adaptation, Physiological↗
PubMed2005

Development and validation of a self-report measure of emotional intelligence as a multidimensional trait domain.

Psychometric review of 33 peer-reviewed studies of six self-report emotional intelligence (EI) measures supports a multidimensional conceptualization of EI. The nature and number of EI facets, however, and their distinctiveness from more established trait domains is unclear. Building on earlier efforts, three studies were undertaken (Ns = 138, 163, 152) to develop self-report measures of 10 facets of EI proposed by Salovey and Mayer (1990). Results support the reliability (internal consistency, test-retest) and validity (content, criterion, construct, structural) of the proposed scales and their distinctiveness among themselves and with respect to more established trait domains (e.g., personality). Specifically, three satisfaction and four cross-cultural adaptability facets were predicted uniquely by 9 of the 10 proposed subscales, controlling for social desirability, the Big Five, positive and negative affect, and self-monitoring. All told, results confirm that trait-EI can be measured using self-report and conceptualized as a distinct multidimensional domain.

Affect↗
PubMed2002

Harrdiness and social support as predictors of stress in mothers of typical children, children with autism, and children with mental retardation.

This study assessed the effects of social support and hardiness on the level of stress in mothers of typical children and children with developmental disabilities. One hundred and twenty mothers participated (40 mothers of children with autism, 40 mothers of children with mental retardation, and 40 mothers of typically developing children). Results indicated significant group differences in ratings of depression, anxiety, somatic complaints and burnout. Regression analyses were conducted to determine the best predictors of the dependent measures. Both hardiness and social support were predictive of successful adaptation. The relationships among hardiness, support and coping are discussed.

Adaptation, Psychological↗
PubMed2001

An 'injury-time integral' model for extrapolating from acute to chronic effects of phosgene.

The present study compares acute and subchronic episodic exposures to phosgene to test the applicability of the 'concentrationxtime' (CxT) product as a measure of exposure dose, and to relate acute toxicity and adaptive responses to chronic toxicity. Rats (male Fischer 344) were exposed (six hours/day) to air or 0.1, 0.2, 0.5 and 1.0 ppm of phosgene one time or on a repeated regimen for up to 12 weeks as follows: 0.1 ppm (five days/week), 0.2 ppm (five days/week), 0.5 ppm (two days/week), or 1.0 ppm (one day/week) (note that the CxT for the three highest exposures was the same). Animals were sacrificed at 4, 8, and 12 weeks during the exposure and after four weeks recovery. Bronchoalveolar lavage (BAL) was performed 18 hours after the last exposure for each time period and the BAL supernatant assayed for protein. Elevated BAL fluid protein was defined as 'acute injury', diminished response after repeated exposure was defined as 'adaptation', and increased lung hydroxyproline or trichrome staining for collagen was defined as 'chronic injury'. Results indicated that exposures that cause maximal chronic injury involve high exposure concentrations and longer times between exposures, not high CxT products. A conceptual model is presented that explains the lack of CxT correlation by the fact that adaptation reduces an 'injury-time integral' as phosgene exposure is lengthened from acute to subchronic. At high exposure concentrations, the adaptive response appears to be overwhelmed, causing a continued injury-time integral, which appears to be related to appearance of chronic injury. The adaptive response is predicted to disappear if the time between exposures is lengthened, leading to a continued high injury-time integral and chronic injury. It has generally been assumed that long, continuous exposures of rodents is a conservative approach for detecting possible chronic effects. The present study suggests that such an approach my not be conservative, but might actually mask effects that could occur under intermittent exposure conditions.

Animals↗
PubMed2003

Attachment relationship experiences and childhood psychopathology.

Human infants form attachments to their caregivers gradually over the course of the first year of life. Qualitatively different types of attachments, which can be identified by the end of the first year, are broadly predictive of subsequent adaptive outcomes for young children. "Disorganized" patterns of attachment have the strongest links to concurrent and subsequent psychopathology, and considerable research has demonstrated both within-the-child and environmental correlates of disorganized attachment. Clinical disorders of attachment have been demonstrated to arise under conditions of social deprivation, such as institutionalization and maltreatment. An emotionally withdrawn/inhibited pattern and an indiscriminate/disinhibited pattern both have been described. Although these clinical types arise under similar conditions of environmental adversity, they tend to have different courses over time. We describe recent findings and highlight areas of emerging consensus and areas of continuing controversy regarding both disorganized patterns of attachment and clinical disorders of attachment in young children.

Adaptation, Psychological↗
PubMed1977

The Mauthner-initiated startle response in teleost fish.

1. A characteristic behaviour, the 'Mauthner-initiated startle response', was recorded and quantitatively analysed with high-speed cinematography (200 frames/sec) after vibrational stimulation in 11 of 13 teleost species which possess Mauthner cells. 2. The latency of the response is 5-10 msec. This behaviour has: (a) an initial phase, the 'fast-body-bend', lasting about 20 msec and consisting of a stereotyped displacement of the head and tail to one side and (b), a second phase, the 'return-flip', consisting of a non-stereotyped flip of the tail to the opposite side. 3. Within 100 msec after the start of the Mauthner-initiated startle response, most fish were displaced 0-5-1-5 body lengths from their initial position. The variability of the animal's location after 100 msec suggests that the behaviour is adaptively non-predictable; 4. In goldfish, the Mauthner-initiated startle response could also be elicited by visual stimulation. 5. We conclude that the fast-body-bend is the direct result of activation of one Mauthner cell and its spinal motor neurone pool. 6. In four species we described examples of apparently non-Mauthner initiated startle responses.

Animals↗
PubMed2026

Computational prediction of a multi-epitope Human Metapneumovirus vaccine candidate through integrated reverse vaccinology and pan-genomic approaches.

Human metapneumovirus (HMPV) is a primary cause of global respiratory infections yet no approved vaccine currently exists. This study computationally predicts a multi-epitope vaccine candidate using a diverse dataset of 65 HMPV sequences spanning five continents. Following the screening of lead proteins for antigenicity and virulence, fifteen highly conserved MHC-I, MHC-II and B-cell epitopes were prioritized. These were integrated with a putative L7/L12 adjuvant using optimized AAY, GPGPG, and KK linkers to design three constructs (HMPV_V1-V3). Structural validation identified HMPV-V2 as the lead candidate that exhibits a Z-score of-5.24 and 87.7% of residues in favored Ramachandran regions indicating excellent stereochemical quality and structural stability. In silico docking indicated a strong predicted binding affinity between HMPV-V2 and the TLR4 receptor (energy: -969.2). Immune simulations predicted a robust adaptive response characterized by high IgG1 titers, memory B-cell maturation, and a Th1-dominant cytokine profile. Furthermore, molecular dynamics simulations suggested exceptional structural integrity for HMPV-V2, maintaining a low RMSD of 8.213 and RMSF of 0.737 throughout the simulation. Optimized in silico cloning into the pET28a (+) vector indicated a high potential for protein expression in E. coli systems. While these findings provide a theoretically grounded blueprint for vaccine development, this study is entirely computational and lacks experimental validation. Further in vitro and in vivo testing is required to confirm the actual safety and immunogenicity of the proposed candidate.

Metapneumovirus↗
PubMed2002

The specificity of maternal disclosure of HIV/AIDS in relation to children's adjustment.

Disclosure experience of 58 HIV-seropositive women was examined as a multi-faceted process comprising eight variables: level, seriousness, breadth, frequency, source, secrecy, age at first disclosure, and time since disclosure. The majority of children (57%) were told that their mothers had HIV/AIDS and were given additional information about mothers' health (64%) including prognosis of potential death (68%). Most were disclosed to by their mothers (75%) and were not asked to keep disclosures secret (66%). For most (68%) discussion regarding mother's health was infrequent. Children, on average, were first disclosed information at age 7 and had been aware of information for 3 years. Disclosure characteristics were related to demographics of mothers and children. Hierarchical multiple regression analyses showed that children asked to keep disclosures secret tended to display more behavior problems than children not asked to keep secrets. However, the specificity of disclosure did not otherwise predict children's adaptive functioning.

Adaptation, Psychological↗