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At least 325 records · Page 18Linked to original sources
PubMed2006

The role of self-determined motivation in the understanding of exercise-related behaviours, cognitions and physical self-evaluations.

Grounded in self-determination theory (Deci & Ryan, 1985), the purpose of the present study was to examine whether amotivation, self-determined and controlling types of motivation could predict a range of exercise-related behaviours, cognitions and physical self-evaluations. Exercisers (n = 375) from ten health clubs in the North of England completed questionnaires measuring exercise motivation, exercise stages of change, number of relapses from exercise, future intention to exercise, barriers self-efficacy, physical self-worth and social physique anxiety. Controlling for age and sex, multiple and logistic regression analyses supported our hypotheses by showing self-determined motivation (i.e. intrinsic motivation and identified regulation) to predict more adaptive behavioural, cognitive and physical self-evaluation patterns than external regulation and amotivation. Introjected regulation was related to both adaptive and maladaptive outcomes. Furthermore, a multivariate analysis of variance revealed that exercisers in the maintenance stage of change displayed significantly more self-determined motivation to exercise than those in the preparation and action stages. The results illustrate the importance of promoting self-determined motivation in exercisers to improve the quality of their experiences, as well as to foster their exercise behaviour. Future research should examine the mechanisms that promote self-determined motivation in exercise.

Adolescent↗
PubMedDate not supplied

Infant temperament and postpartum depression: a review.

Although limited in number, reported research studies indicate a relationship between maternal perceptions of infant temperament and postpartum depression. Excessive crying in particular and the extent of adaptability and predictability have been implicated as infant behavioral indices. In this article, we present the results of a review of the literature linking early infant temperament to postpartum depression. Measurement issues for both infant temperament and depression are discussed. Recommendations for future research are offered.

Crying↗
PubMed1997

Medical complications of anorexia nervosa.

Anorexia nervosa is often characterized by progressive deterioration in many different organ systems. Most medical complications are the result of starvation and can be reversed with a well-planned refeeding program. While some of the complications of anorexia nervosa are predictable physiologic adaptations to the self-imposed starvation, many others are potentially life threatening. It is therefore incumbent upon all primary care physicians to become familiar with this disorder, because it is increasing in incidence and is commonly burdened by substantial chronicity and recidivism.

Adolescent↗
PubMed2001

Analysis of key decision-making incidents in the life of a nursing home resident.

PURPOSE: This study examined change in the decision-making autonomy of a single nursing facility resident. DESIGN AND METHODS: This case analysis was part of a larger 3-year ethnographic investigation of decision-making events in four nursing facilities. In this case analysis, the resident, her daughter, and three staff members closely associated with the resident's care were each interviewed five times over a 15-month period. RESULTS: Analysis of interview transcripts revealed four themes in decision making. Temporal change was evident in a complex scenario regarding room changes. Spatial context reflected the need for predictability and adaptability in decisions using space. Interdependence of decisions and decision makers was most evident with medical treatment and health care decisions. Awareness, being informed, and knowing what was going on was the final theme. IMPLICATIONS: Despite having the best interests of the resident in mind, the process of decision making in nursing facilities may contribute to a pattern of gradual withdrawal of decisional autonomy from residents regardless of their ability to make decisions.

Activities of Daily Living↗
PubMed2006

Longitudinal relationships between early adolescent family functioning and youth adjustment: an examination of the moderating role of very low birth weight.

OBJECTIVE: To examine longitudinal relations between early adolescent family conflict and late adolescent psychosocial adjustment, and the moderating role of low birth weight. METHODS: Three groups of adolescents (48 with birth weight <750 g, 46 with birth weight 750-1499 g, and 51 term-born controls) and their parents completed ratings of family conflict at age 11 (Time 1). Parent, teacher, and youth reports of psychosocial functioning were obtained at ages 11 and 17 (Time 2). RESULTS: Birth weight moderated the relationship between Time 1 adolescent-perceived conflict and change in adolescent behavioral functioning. For adolescents with histories of <750 g birth weight, adolescent-perceived conflict predicted less adaptive changes in teacher-reported total behavior problems and externalizing problems. CONCLUSIONS: Small disruptions to the parent-child relationship have negative implications for the later well-being of adolescents with extreme levels of low birth weight. Clinical attention to resolving early adolescent conflict may promote adaptive adjustment.

Adjustment Disorders↗
PubMed2003

Workshop overview: use of genomic data in risk assessment.

The completion of the Human Genome Project has provided the foundation to analyze the expression of all genes transcribed in a specific cell, as well as a reference against which to assess genetic variability and its impact on susceptibility. Recent advances in genomic technologies have set the stage for better understanding and predicting individual adaptive and toxicological responses after toxicant exposure. Thus, it is now possible to simultaneously assess expression levels for thousands of different genes using DNA microarrays, as well as assess posttranscriptional and posttranslational events using high throughput proteomics. Similarly, the risk of toxicant exposure-induced disease used to be estimated across populations with widely varying responses. However, new high-throughput genomic technologies have the potential to greatly improve the accuracy of risk assessment, allowing identification of sensitive subpopulations at risk and ultimately leading to personalized risk profiles based on genetic composition. Recognizing the importance these technologies will have on the practice of risk assessment and the development of regulatory guidelines, the Society of Toxicology sponsored a workshop to evaluate the current status of genomic research; the ethical, legal, and social issues associated with these approaches; and, in this context, how data derived from these technologies would impact risk assessment. This article summarizes the evaluation by experts in genomic research and risk assessment in the first workshop to provide a forum for interaction between these scientific disciplines.

Animals↗
PubMed1997

Adaptation of ECOSYS-87 to Hong Kong environmental conditions.

This paper describes the adaptation work carried out on the radioecological model ECOSYS for radionuclide transfer in the Hong Kong ecological environment. The adapted model predicts that the ingestion dose due to dry deposition in Hong Kong shows less pronounced seasonal dependence than that in Germany. This is mainly attributed to differences in climate, agricultural and farming practices adopted in the two places. Brief discussions on model sensitivity, uncertainty, and validation are also given.

Agriculture↗
PubMed2006

Experience with cranial implant-based prosthetic reconstruction.

Reconstruction of acquired or congenitally absent facial structures is a challenging task for the reconstructive surgeon. Often inadequate soft tissue, cartilaginous, or osseous support exists for a reconstruction which is functional, aesthetic, and achieved with a reasonable effort on the part of the surgeon and patient. Prosthetic reconstruction of these structures utilizing cranial implants is a viable option which offers several advantages when compared to traditional reconstructive techniques. We present our experience with 114 cranial implants in 32 patients for craniofacial reconstruction. One hundred fourteen cranial implants were placed in a total of 32 patients for reconstruction of facial structures. Indications for cranial implants with prosthetic reconstruction were lack of adequate tissue for reconstruction, failed reconstructive attempts, and selection of the technique by the patient. Seventy-two implants were placed in the mastoid region, 31 within the orbit, 7 within the nasal cavity, with four additional implants for the reconstruction of eyebrows. Cranial implants were followed by clinical and radiographic examination at intervals ranging from 3-46 months (mean 15.3 months). Patient records were retrospectively reviewed for surgical complications, soft tissue reactions, infections, and implant failures. The total success rate of cranial implantation in the study group was 92.9% (106/114). Surgical complications occurred in three of the 32 patients (9.3%). All cranial implants were successfully reconstructed after integration. Seven percent of the implants failed after initial integration was successful. The rate of significant soft tissue reactions or frank infection observed among the implanted patients was 6.1%. Titanium cranial implants coupled with custom prosthetic reconstruction offer an excellent alternative to traditional surgical techniques in the reconstruction of acquired or congenitally absent facial structures. Predictability, prosthetic adaptability, as well as superior aesthetics are major advantages to this technique when compared to traditional surgical reconstructive techniques.

Adolescent↗
PubMed2000

Gating energies and forces of the mammalian hair cell transducer channel and related hair bundle mechanics.

We quantified the molecular energies and forces involved in opening and closing of mechanoelectrical transducer channels in hair cells using a novel generally applicable method. It relies on a thermodynamic description of the free energy of an ion channel in terms of its open probability. The molecular gating force per channel as reflected in hair bundle mechanics is shown to equal kT/I(X) x dI(X)/dX, where I is the transducer current and X the deflection of the hair bundle. We applied the method to previously measured I(X) curves in mouse outer hair cells (OHCs) and vestibular hair cells (VHCs). Contrary to current models of transduction, gating of the transducer channel was found to involve only a finite range of free energy (< 10 kT), a consequence of our observation that the channel has a finite minimum open probability of ca. 1% for inhibitory bundle deflections. The maximum gating forces per channel of both cell types were found to be comparable (ca. 300-500 fN). Because of differences in passive restoring forces, gating forces result in very limited mechanical nonlinearity in OHC bundles compared to that in VHC bundles. A kinetic model of channel activation is proposed that accounts for the observed transducer currents and gating forces. It also predicts adaptation-like effects and spontaneous bundle movements ensuing from changes in state energy gaps possibly related to interactions of the channel with calcium ions.

Animals↗
PubMed2004

Facial resemblance increases the attractiveness of same-sex faces more than other-sex faces.

Our reactions to facial self-resemblance could reflect either specialized responses to cues of kinship or by-products of the general perceptual mechanisms of face encoding and mere exposure. The adaptive hypothesis predicts differences in reactions to self-resemblance in mating and prosocial contexts, while the by-product hypothesis does not. Using face images that were digitally transformed to resemble participants, I showed that the effects of resemblance on attractiveness judgements depended on both the sex of the judge and the sex of the face being judged: facial resemblance increased attractiveness judgements of same-sex faces more than other-sex faces, despite the use of identical procedures to manipulate resemblance. A control experiment indicated these effects were caused neither by lower resemblance of other-sex faces than same-sex faces, nor by an increased perception of averageness or familiarity of same-sex faces due to prototyping or mere exposure affecting only same-sex faces. The differential impact of self-resemblance on our perception of same-sex and other-sex faces supports the hypothesis that humans use facial resemblance as a cue of kinship.

Adult↗
PubMed2006

Small body size in an insect shifts development, prior to adult eclosion, towards early reproduction.

Life-history theory has suggested that individual body size can strongly affect the allocation of resources to reproduction and away from other traits such as survival. In many insects, adults eclose with a proportion of their potential lifetime egg production that is already mature (the ovigeny index). We establish for the solitary parasitoid wasp Aphaereta genevensis that the ovigeny index decreases with adult body size, despite both initial egg load and potential lifetime fecundity increasing with body size. This outcome is predicted by adaptive models and is the first unequivocal intraspecific demonstration. Evidence suggests that a high ovigeny index carries a cost of reduced longevity in insects. Our results therefore contribute to the emerging evidence that small body size can favour a developmental shift in juveniles that favours early reproduction, but which has adverse late-life consequences. These findings are likely to have important implications for developmental biologists and population biologists.

Animals↗
PubMed2005

DNA barcodes for biosecurity: invasive species identification.

Biosecurity encompasses protecting against any risk through 'biological harm', not least being the economic impact from the spread of pest insects. Molecular diagnostic tools provide valuable support for the rapid and accurate identification of morphologically indistinct alien species. However, these tools currently lack standardization. They are not conducive to adaptation by multiple sectors or countries, or to coping with changing pest priorities. The data presented here identifies DNA barcodes as a very promising opportunity to address this. DNA of tussock moth and fruit fly specimens intercepted at the New Zealand border over the last decade were reanalysed using the cox1 sequence barcode approach. Species identifications were compared with the historical dataset obtained by PCR-RFLP of nuclear rDNA. There was 90 and 96% agreement between the methods for these species, respectively. Improvements included previous tussock moth 'unknowns' being placed to family, genera or species and further resolution within fruit fly species complexes. The analyses highlight several advantages of DNA barcodes, especially their adaptability and predictive value. This approach is a realistic platform on which to build a much more flexible system, with the potential to be adopted globally for the rapid and accurate identification of invasive alien species.

Animals↗
PubMed2001

A model-updating procedure to stimulate piezoelectric transducers accurately.

The use of numerical calculations based on finite element methods (FEM) has yielded significant improvements in the simulation and design of piezoelectric transducers piezoelectric transducer utilized in acoustic imaging. However, the ultimate precision of such models is directly controlled by the accuracy of material characterization. The present work is dedicated to the development of a model-updating technique adapted to the problem of piezoelectric transducer. The updating process is applied using the experimental admittance of a given structure for which a finite element analysis is performed. The mathematical developments are reported and then applied to update the entries of a FEM of a two-layer structure (a PbZrTi-PZT-ridge glued on a backing) for which measurements were available. The efficiency of the proposed approach is demonstrated, yielding the definition of a new set of constants well adapted to predict the structure response accurately. Improvement of the proposed approach, consisting of the updating of material coefficients not only on the admittance but also on the impedance data, is finally discussed.

Journal Article↗
PubMed1995

The significance of self-reported anxious symptoms in first grade children: prediction to anxious symptoms and adaptive functioning in fifth grade.

In an earlier study of an epidemiologically defined sample of first grade children, primarily between the ages of 5 and 6, self-reported anxious symptoms proved relatively stable and were significantly related to adaptive functioning. In the present study we follow that cohort of first graders longitudinally and assess the prognostic value of self-reports of anxious symptoms in first grade with respect to anxious symptoms and adaptive functioning in the late elementary school years or at about age 10. First grade anxious symptoms were found to have significant prognostic value in terms of levels of anxious symptoms and adaptive functioning in fifth grade.

Adaptation, Psychological↗
PubMed2005

Relationships among growth, development and plastic response to environment quality in a perennial plant.

Phenotypic traits differ between plants in different environments and within individuals as they grow and develop. Comparing plants in different environments at a common age can obscure the developmental basis for differences in phenotype means in different environments. Here, we compared trait means and patterns of trait ontogeny for perennial (Viola septemloba) plants growing in environments that differed in quality either naturally or due to experimental manipulation. Consistent with predictions for adaptive stress resistance, plants grown in lower-quality environments allocated proportionately more biomass to roots and rhizomes, and produced smaller, thicker and longer-lived leaves. The developmental trajectory of almost all traits differed between environments, and these differences contributed to observed differences in trait means. Plants were able to alter their initial developmental trajectory in response to an increase in resources after 8 wk of growth. This result contrasts with previous findings, and may reflect a difference in the way that annual and perennial species respond to stress. Our results demonstrate the complexity of interactions between the environment and the development of the phenotype that underlie putatively adaptive plastic responses to environment quality.

Adaptation, Physiological↗
PubMed1998

Plasticity in an electrosensory system. III. Contrasting properties of spatially segregated dendritic inputs.

Efferent neurons of the first-order electrosensory processing center of the brain, the electrosensory lateral line lobe (ELL), receive electroreceptor afferent input as well as feedback inputs descending from higher centers. These ELL efferents, pyramidal cells, adaptively filter predictable patterns of sensory input while preserving sensitivity to novel stimuli. The filter mechanism involves integration of centrally generated predictive inputs with the afferent inputs being canceled. The predictive inputs, referred to as "negative image" inputs, terminate on pyramidal cell apical dendrites and generate responses that are opposite those resulting from the predictable afference, hence integration of these signals results in attenuation of pyramidal cell responses. The system also shows a robust form of plasticity; the pyramidal cells learn, with a time course of a few minutes, to cancel new patterns of repetitive inputs. This is accomplished by adjusting the strength of excitatory and inhibitory apical dendritic inputs according to an anti-Hebbian learning rule. This study focuses on the properties of two separate pathways that convey descending information to pyramidal cell apical dendrites. One pathway terminates proximally, nearer to the pyramidal cell body, whereas the other terminates distally. Recordings of ELL evoked potentials, extracellular pyramidal cell spike responses, and intracellularly recorded synaptic potentials show that the pyramidal cells respond oppositely to moderate-frequency (> approximately 8 Hz) single pulse stimulation or repeated (1/s) tetanic activation of these two pathways. Repetitive activation of the proximally terminating pathway results in highly facilitating responses due to potentiation of pyramidal cell excitatory postsynaptic potentials (EPSPs). These same stimuli applied to the distally terminating pathway result in a reduction of pyramidal cell responses due to depression of EPSPs and potentiation of inhibitatory postsynaptic potentials (IPSPs). Anti-Hebbian plasticity was demonstrated by pairing tetanic stimulation of either pathway with changes in the postsynaptic cell's membrane potential. After stabilization of the response potentiation due to tetanic stimulation of the proximally terminating pathway, paired postsynaptic hyperpolarization resulted in further increases in spike responses and additional potentiation of pyramidal cell EPSPs. Paired postsynaptic depolarization reduced subsequent responses to the tetanus, depressed EPSP amplitudes, and, in many cases, potentiated IPSPs. The same pattern of plasticity was observed when postsynaptic hyper- or depolarization was paired with tetanic stimulation of the distally terminating pathway except that the plasticity was superimposed on the depressed pyramidal cell responses resulting from stimulating this pathway alone. Modulation of a postsynaptic form of synaptic depression is proposed to account for the anti-Hebbian plasticity associated with both pathways.

Animals↗
PubMed1999

Deep brain stimulation of the ventral intermediate nucleus of the thalamus for control of tremors in Parkinson's disease and essential tremor.

The beneficial effects of ventral intermediate nucleus (VIM) stimulation were evaluated in 20 patients with tremor refractory to medical therapy. Thalamic stimulation is a non-ablative procedure which has the advantage of a reversible, non-destructive lesion. Eleven patients [7 with Parkinson's disease (PD) and 4 with essential tremor (ET)] received unilateral VIM implantation, while 9 patients had staged bilateral VIM implantation (4 with PD, 5 with ET). PD patients showed a significant improvement in contralateral arm and leg rest tremor and ipsilateral leg rest tremor (p < 0.02) at a mean follow-up period of 16.2 +/- 7.0 months. Patients with PD did not demonstrate any significant decrease in medication use at follow-up. ET patients demonstrated significant improvement in postural and action tremor in the contralateral arm (p < 0.001), but no significant improvement in the contralateral leg tremor at follow-up. Significant improvements were also seen in ET patients in the Clinical Rating Scale for Tremor (p < 0.001) with respect to several activities of daily living at a mean follow-up of 14.9 +/- 8. 1 months. Deep brain stimulation is a safe and effective treatment for severe tremor refractory to medications. It is a highly effective, reversible, adaptable, and predictable procedure which avoids the complication of cognitive deficit seen in patients with bilateral thalamotomies.

Aged↗