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PubMed1989

The inheritance of acquired epigenetic variations.

There is evidence that the functional history of a gene in one generation can influence its expression in the next. In somatic cells, changes in gene activity are frequently associated with changes in the pattern of methylation of the cytosines in DNA; these methylation patterns are stably inherited. Recent work suggests that information about patterns of methylation and other epigenetic states can also be transmitted from parents to offspring. This evidence is the basis of a model for the inheritance of acquired epigenetic variations. According to the model, an environmental stimulus can induce heritable chromatin modifications which are very specific and predictable, and might result in an adaptive response to the stimulus. This type of response probably has most significance for adaptive evolution in organisms such as fungi and plants, which lack distinct segregation of the soma and germ line. However, in all organisms, the accumulation of specific and random chromatin modifications in the germ line may be important in speciation, because these modifications could lead to reproductive isolation between populations. Heritable chromatin variations may also alter the frequency and distribution of classical mutations and meiotic recombination. Therefore, inherited epigenetic changes in the structure of chromatin can influence neo-Darwinian evolution as well as cause a type of "Lamarckian" inheritance.

Base Sequence↗
PubMed2002

Fuzzy logic model of Langmuir probe discharge data.

Plasma models are crucial to gain physical insights into complex discharges as well as to optimizing plasma-driven processes. As an alternative to physical model, a qualitative model was constructed using adaptive fuzzy logic called adaptive network fuzzy inference system (ANFIS). Prediction performance of ANFIS was evaluated on two sets of experimental discharge data. One referred to as hemispherical inductively coupled plasma (HICP) was characterized with a 2(4) full factorial experiment, in which the factors that were varied include source power, pressure, chuck position, and Cl2 flow rate. The other called multipole ICP was characterized by performing a 3(3) full factorial experiment on the factors, including source power, pressure, and Ar flow rate. Trained ANFIS models were tested on eight and 16 experiments not pertaining to previous training data for HICP and MICP, respectively. Plasma attributes modeled include electron density. electron temperature, and plasma potential. The performance of ANFIS was optimized as a function of a type of membership function, number of membership function, and two learning factors. The number of membership functions was different depending on the type of plasma data and employing too large number of membership functions resulted in a drastic degradation in prediction performances. Optimized ANFIS models were compared to statistical regression models and demonstrated improved predictions in all comparisons.

Journal Article↗
PubMed1998

[Preliminary validation of the Child Abuse Potential Inventory in Argentina].

OBJECTIVE: To know the ability of the CAP Inventory (Milner, 1986) to discriminate between child physical abusers and nonabusers in Argentina, and to know its reliability. To conduct an item analysis in order to know the capability of the Abuse Scale items for discrimination between both groups of subjects. METHOD: The CAP Inventory was applied to two groups of subjects: 40 child physical abusers and 40 nonabusers. Both groups were matched in gender, age, educational level, family income, martial status, number of children, and gender and age of children. RESULTS: Fifty-four items discriminated (p < .05) between both groups of subjects. The reliability coefficient of the Abuse Scale was adequate (alpha = .94). Twenty items with the best capability for discrimination were selected. More than 97% (97.4%) of subjects were correctly classified (94.4% for physical abusers and 100% for nonabusers). The Abuse Scale present similar psychometric characteristics than the American and Spanish versions. CONCLUSION: This is the first study in Argentina with the objective of CAP adaptation and validation. The discriminant and predictive capability of the Abuse Scale are promising for Argentina. However, complementary studies with different samples are needed in order to obtain reliable data and a preliminary version of the Inventory.

Adult↗
PubMed2000

Global networking for assessment of impacts of global change on plant pests.

Global change encompasses changes in atmospheric composition, climate and climate variability, and land cover and land use. The occurrence of these changes and their interactive effects on biological systems are worldwide; thus, an effective global change research and impact assessment program must be based on international and interdisciplinary research and communication. With this in mind, several collaborative research networks with a focus on global change have been established in the biological sciences. They include the Global Change and Terrestrial Ecosystems (GCTE) Core Project of the International Geosphere-Biosphere Programme (IGBP) which aims to predict the effects of global change on terrestrial ecosystems, including agriculture and production forestry. Because of the importance of plant pests (arthropods, microbial pathogens, weeds) as yield-reducing factors in agriculture and as early indicators of global change, GCTE initiated a network Activity on "Global Change Impacts on Pests, Diseases and Weeds" with the overall goal of developing a predictive capability for impact assessment and adaptation. The network's specific objectives, contributing research projects, initial results and future challenges are discussed.

Journal Article↗
PubMedDate not supplied

Functional grouping in residential homes for people with intellectual disabilities.

The effects of functional grouping of people with intellectual disabilities on care practices in small residential homes in the community were investigated. A group comparison and a matched-pairs comparison were carried out in settings where less than or more than 75% residents were non-verbal, non-ambulant, had severe challenging behaviour, severe social impairment or were verbal and ambulant. Further analysis, focused on those with challenging behaviour was carried out using ordinal regression. In the group-comparison study, no significant differences were found for three of the five groups. Residents who were non-ambulant were rated as receiving care with less interpersonal warmth in grouped settings; residents with severe challenging behaviour were rated as receiving less good care practices in four respects (interpersonal warmth, assistance from staff, level of speech and staff teamwork) in grouped settings. The matched-pairs comparison found significant differences only for people with challenging behaviour, where grouped settings achieved less good results in terms of interpersonal warmth and staff teamwork. Higher adaptive behaviour and mixed settings were predictive of better care practices on 13 of 14 items of the Active Support Measure (ASM), with some setting variables also predictive for some items. Care practices only appear to vary for people with challenging behaviour, where grouped settings appear to offer less good results in some respects.

Activities of Daily Living↗
PubMedDate not supplied

FLUFF-BALL, a template-based grid-independent superposition and QSAR technique: validation using a benchmark steroid data set.

The Flexible Ligand Unified Force Field (FLUFF) is a molecular mechanistic superposition algorithm utilizing a template structure, on top of which the ligand(s) are superimposed. FLUFF enables a flexible semiautomatic superimposition in which the ligand and the template are allowed to seek the best common conformation, which can then be used to predict the biological activity by Boundless Adaptive Localized Ligand (BALL). In BALL, the similarity of the electrostatic and van der Waals volumes of the template and ligand is evaluated using the template-based coordinate system which makes the FLUFF-BALL invariant as to the rotations and translations of the global coordinate system. When tested using the CBG (corticosteroid binding globulin) affinities of 31 benchmark steroids, the FLUFF-BALL technique produced results comparable to standard 3D-QSAR methods. Supplementary test calculations were performed with five additional data sets. Due to its high level of automation and high throughput, the FLUFF-BALL is highly suitable for use in drug design and in scanning of large molecular libraries.

Algorithms↗
PubMed2002

Cycloheptatrienyl oxyallyl. An observable oxyallyl?

Density functional calculations have been carried out for cycloproylidene-, cyclopentylidene-, and tropyllideneallene oxides (7-9) and the reaction pathway for their conversion to the corresponding oxyallyls (10-12) and cyclopropanones (13-15) in order to probe the electronic structure of the intermediate oxyallyls. All three oxyallyls were found to be stabilized with respect to their allene oxides in comparison to the unsubstituted allene oxide and oxyallyl. For 7 and 9 the stabilization can be attributed to the zwitterionic character of the oxyallyls, while for 8 the stabilization can be attributed to its diradical character. This suggests that oxyallyl is capable of "adapting" to its local environment. Calculations predict that oxyallyl 12 should be an observable intermediate in the absence of nucleophiles, since it is calculated to be of lower energy than either the allene oxide 9 or the cyclopropanone 15.

Allyl Compounds↗
PubMed2003

Relationship-specific unsupportive social interactions and depressive symptoms among women living with HIV/AIDS: direct and moderating effects.

Although unsupportive social interactions have demonstrated strong relations with psychological adjustment to illness, little research has been directed at the differential effects of unsupportive interactions from different relationship sources (i.e., family, friends, or a lover/spouse). The present study examines whether the source of unsupportive social interactions has differential main and interactive relations with depressive symptoms among an ethnically diverse sample of women living with HIV/AIDS (N = 146). After imposing demographic controls, unsupportive social interactions from family were found to have a main effect predicting more depressive symptoms. Furthermore, a significant interaction was identified between unsupportive interactions from a lover/spouse and from friends, such that high levels of unsupportive interactions from either or both sources predicted high levels of depressive symptoms. Only when neither source of unsupportive interactions was at a high level were nonclinical levels of depressive symptoms predicted.

Adaptation, Psychological↗
PubMed2006

Positive and negative recency effects in retirement savings decisions.

Retirement savings decisions can be influenced by the fund composition of the retirement savings plan. In 2 experiments, strong composition effects were observed, with a larger percentage of resources being invested in stock funds when more stock than bond funds were offered. Although participants changed their allocations repeatedly, the opportunity to learn did not alter the composition effects. Learning processes led to positive and negative recency effects as well, providing evidence that allocations were strongly influenced by the recent performance of the different allocation options. Two learning models were tested to explain these learning processes. The first, a local adaptation learning model, assumes that people change their behavior on the basis of recent experience, whereas the second, a reinforcement learning model, assumes that decisions are made on the basis of the totality of accumulated experience. The local adaptation model was more accurate in predicting allocation decisions, in explaining positive and negative recency effects, and in showing why composition effects are not overcome by learning.

Adult↗
PubMed1997

Synaptic plasticity in a cerebellum-like structure depends on temporal order.

Cerebellum-like structures in fish appear to act as adaptive sensory processors, in which learned predictions about sensory input are generated and subtracted from actual sensory input, allowing unpredicted inputs to stand out. Pairing sensory input with centrally originating predictive signals, such as corollary discharge signals linked to motor commands, results in neural responses to the predictive signals alone that are 'negative images' of the previously paired sensory responses. Adding these 'negative images' to actual sensory inputs minimizes the neural response to predictable sensory features. At the cellular level, sensory input is relayed to the basal region of Purkinje-like cells, whereas predictive signals are relayed by parallel fibres to the apical dendrites of the same cells. The generation of negative images could be explained by plasticity at parallel fibre synapses. We show here that such plasticity exists in the electrosensory lobe of mormyrid electric fish and that it has the necessary properties for such a model: it is reversible, anti-hebbian (excitatory postsynaptic potentials (EPSPs) are depressed after pairing with a postsynaptic spike) and tightly dependent on the sequence of pre- and postsynaptic events, with depression occurring only if the postsynaptic spike follows EPSP onset within 60 ms.

Animals↗
PubMed2003

Synaptic depression in the localization of sound.

Short-term synaptic plasticity, which is common in the central nervous system, may contribute to the signal processing functions of both temporal integration and coincidence detection. For temporal integrators, whose output firng rate depends on a running average of recent synaptic inputs, plasticity modulates input synaptic strength and thus may directly control signalling gain and the function of neural networks. But the firing probability of an ideal coincidence detector would depend on the temporal coincidence of events rather than on the average frequency of synaptic events. Here we have examined a specific case of how synaptic plasticity can affect temporal coincidence detection, by experimentally characterizing synaptic depression at the synapse between neurons in the nucleus magnocellularis and coincidence detection neurons in the nucleus laminaris in the chick auditory brainstem. We combine an empirical description of this depression with a biophysical model of signalling in the nucleus laminaris. The resulting model predicts that synaptic depression provides an adaptive mechanism for preserving interaural time-delay information (a proxy for the location of sound in space) despite the confounding effects of sound-intensity-related information. This mechanism may help nucleus laminaris neurons to pass specific sound localization information to higher processing centres.

Acoustic Stimulation↗
PubMed2001

Validation of the language development survey (LDS): a parent report tool for identifying language delay in toddlers.

Two studies are reported demonstrating the reliability, validity, and clinical utility of the Language Development Survey (LDS; L. Rescorla, 1989) as a screening tool for the identification of expressive language delay in toddlers. In Study 1, 422 children (ages 24-26 months) were screened with the LDS in an epidemiological survey. The LDS manifested excellent concurrent validity with a brief direct screening measure of expressive vocabulary. Using the Rescorla (1989) Delay 3 cutoff of fewer than 50 words or no word combinations, 9.7% of the sample were language delayed (32 boys, 9 girls). In Study 2, 33 children identified as "at-risk" by the LDS Delay 3 cutoff and 33 typically developing children, matched on age, socioeconomic status, and gender, were seen for in-depth follow-up assessment approximately 3 weeks later. The LDS test-retest reliability was .97. The LDS correlated highly with Reynell Receptive and Expressive Language Scale scores, Bayley Mental Development Index, and Vineland Adaptive Behavior Composite. Sensitivity, specificity, positive predictive value, and negative predictive value between the screening LDS and the follow-up Reynell Expressive Language Scale were generally impressive. Finally, the at-risk group scored significantly lower than the LDS-identified typically developing group on all follow-up measures except the Child Behavior Checklist/2-3.

Child Language↗
PubMed2003

Local mate competition with lethal male combat: effects of competitive asymmetry and information availability on a sex ratio game.

We constructed a sex allocation model for local mate competition considering the asymmetry of competitive abilities among sons. This model assumes two females of a parasitoid wasp oviposit on the same host in sequential order. The evolutionarily stable strategy will be in either Stackelberg or Nash equilibrium, depending on whether the females can recognize their opponent's sex ratio or not, respectively. The Nash equilibrium predicts the second female produce more males than the first. If the second female is able to know and respond to the strategy of the first (a Stackelberg equilibrium), the first will decide an optimal sex ratio assuming that the second reply to it. Under such an assumption, our model predicts that not producing sons is adaptive for the second female when the sons she produces have low competitive ability. Males of parasitoid wasps Melittobia spp. are engaged in lethal male-male combat, indicating large asymmetry in mating success among sons. If females have the ability to recognize their opponent's sex ratio, our model suggests that the severe lethal male-male combat may be one factor explaining their extremely female-biased sex ratio that is unexplainable by pre-existent models.

Aggression↗
PubMed1982

Salt taste sensitivity and stimulus volume: effect of stimulus residuals.

Sodium chloride (NaCl) stimulus residuals were seen to be greater after a large-volume NaCl rinse than after a small-volume rinse. Predicted changes in sensitivity dependent on adapting concentrations determined by residual levels were confirmed by signal detection R-index measures of sensitivity. R-index values were seen to be independent of the volume of the test water and NaCl stimuli used in their determination.

Adaptation, Physiological↗
PubMed1987

Effects of orientation-selective adaptation on the Zöllner illusion.

The model of inhibitory interaction between orientation detectors was examined by prolonged presentation of grating patterns (which was expected to induce orientation-selective adaptation) before measurement of the Zöllner illusion. Adaptation effects were measured under conditions which excluded intrusion by the tilt aftereffect. In experiment 1, illusion magnitude greatly decreased only when the orientation of the adapting grating was the same as that of the inducing lines, which confirmed the first prediction deduced from the model. There was no effect of adapting grating when it was oriented more than 20 degrees away from the inducing lines. In experiment 2, adaptation effects were selective not only to orientation but also to spatial frequency. In experiment 3 it was shown that illusion reduction was mediated neither by lowered apparent contrast of the inducing lines nor by retinal adaptation. The results are discussed with respect to the nature of adaptation and possible physiological correlates.

Adaptation, Ocular↗
PubMed1994

Perception of motion in depth from luminous rotating spirals: directional asymmetries during and after rotation.

Motion aftereffect (MAE) following spiral rotation is often asymmetrical: centrifugal MAE exceeds centripetal MAE. Pronounced MAE asymmetry has been reported for conditions--especially with a minimal background pattern--promoting perception of motion in depth. Such conditions are predicted to elicit motion asymmetry during adaptation. In the present study observers viewed luminous spirals monocularly in the dark; they timed, and scaled for convincingness, motion in depth during and after rotation. Motion in depth during rotation was often almost continuous, but recession was more convincing than was approach. Approaching MAE lasted longer and was more convincing than was receding MAE: the duration difference was more pronounced than has been found in other MAE studies, corroborating the link between MAE asymmetry and motion in depth. A possible line of explanation resides in comparing spiral motion in depth with real motion in depth of objects: in particular, the rapid visual change and collision with the observer that characterises real approach of an object is lacking in spiral approach. Interspecies differences for 'looming' and MAE are discussed.

Adult↗
PubMed2005

The efficacy of a structured group therapy intervention in improving communication and coping skills for adult cochlear implant recipients.

This paper reports on an evaluation of a structured group therapy intervention for adult cochlear implant (CI) recipients designed to improve overall communication and coping skills. 33 adult CI recipients (14 males, 19 females; mean age 61; 1-14 years since Cl) participated in a 2-day structured group therapy intervention with a follow-up session 4 weeks later. Measures were: communication behaviors (CPHI), assertiveness (Rathus), depression (DASS), and behavior during conversation (Dyalog). TCI personality traits were utilized as predictors of change. Repeated measures analyses showed that participants demonstrated significant improvements on measures of assertiveness, emotional well-being, and coping behaviors at 3 months post-intervention that persisted at a 12-month follow-up. Several personality traits predicted change. Although subjects had presumably adapted to their cochlear implants and had learned communication strategies in hearing rehabilitation programs, the improvements on several measures suggest that a structured group therapy intervention can enhance outcome following cochlear implantation.

Adaptation, Psychological↗
PubMed2004

Calcium regulation of single ryanodine receptor channel gating analyzed using HMM/MCMC statistical methods.

Type-II ryanodine receptor channels (RYRs) play a fundamental role in intracellular Ca(2+) dynamics in heart. The processes of activation, inactivation, and regulation of these channels have been the subject of intensive research and the focus of recent debates. Typically, approaches to understand these processes involve statistical analysis of single RYRs, involving signal restoration, model estimation, and selection. These tasks are usually performed by following rather phenomenological criteria that turn models into self-fulfilling prophecies. Here, a thorough statistical treatment is applied by modeling single RYRs using aggregated hidden Markov models. Inferences are made using Bayesian statistics and stochastic search methods known as Markov chain Monte Carlo. These methods allow extension of the temporal resolution of the analysis far beyond the limits of previous approaches and provide a direct measure of the uncertainties associated with every estimation step, together with a direct assessment of why and where a particular model fails. Analyses of single RYRs at several Ca(2+) concentrations are made by considering 16 models, some of them previously reported in the literature. Results clearly show that single RYRs have Ca(2+)-dependent gating modes. Moreover, our results demonstrate that single RYRs responding to a sudden change in Ca(2+) display adaptation kinetics. Interestingly, best ranked models predict microscopic reversibility when monovalent cations are used as the main permeating species. Finally, the extended bandwidth revealed the existence of novel fast buzz-mode at low Ca(2+) concentrations.

Algorithms↗