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PubMed1977

The measurement of emotional concepts in patients with temporal lobe epilepsy.

Eleven temporal lobe epileptics, implanted with depth electrodes, 21 post-lobectomy epileptics, and 24 orthopedic controls were given a semantic differential test, which measured responses along 4 scales (evaluative, potency, activity, and danger) of 18 emotional and 1 non-emotional concepts. Results showed that post-lobectomy females thought of themselves as more dangerous than did orthopedic control females. Both post-lobectomy and implantation patients found the anger-hostility and fear-anxiety concepts less bad, potent, active, and dangerous than did the orthopedic controls. The post-lobectomy and implantation patients found the concept "sexual intercourse" and other non-sexual love-related concepts to be worse and more dangerous, but less potent and active than did the orthopedic controls.

Adolescent↗
PubMed1996

Postpartum fatigue: clarifying a concept.

This paper describes the multifaceted approach employed to clarify the concept of postpartum fatigue. The process began with a literary analysis, which gave rise to questions about the defining characteristics of postpartum fatigue and its differentiation from related concepts such as tiredness and depression. A series of qualitative and quantitative studies were carried out to examine new mothers' characterizations of their fatigue, the indicators and predictors of postpartum fatigue, and the differences between fatigue and depression. The evolving concept clarification suggests that postpartum fatigue is most effectively conceptualized as a multidimensional concept with physical and mental aspects that is different from tiredness and can be differentiated from postpartal depression or milder "baby blues," with which there is some overlap.

Concept Formation↗
PubMed1997

Effects of frequency of feedback on transfer in concept identification.

Two experiments were performed to investigate the effects of frequency of feedback on immediate- and delayed-transfer tasks in concept identification. In the first experiment, subjects were required to learn new concepts from the same category for the transfer tasks, whereas in the second experiment the transfer tasks involved concepts from a different category. Among the major findings was that although lowering the percentage of feedback trials slows concept attainment, it facilitated transfer on all transfer tasks. In general, the fewer the number of feedback trials subjects received, the greater the amount of transfer. The results are consistent with other studies that suggest that conditions that make it more difficult for subjects to initially learn a task may have positive benefits for transfer.

Adult↗
PubMedDate not supplied

Afrocentrism and self-concept.

The promotion of healthy self-concept in clients is an important outcome in nursing practice. The nurse's own self-concept is also an important factor affecting one's ability to meet the needs of others. Several scholars who speak from an Afrocentric cultural base echo a warning about the potential deleterious effects on self-concept that can occur as a result of internalization of the perspectives of other cultures to the exclusion of perspectives from one's own culture. Proponent and opponent arguments have been articulated concerning the question, "Are there African American perspectives on biomedical ethics?" In this paper, the proponent view is supported, and the potential influence of Afrocentrism on self-concept is explored.

Black or African American↗
PubMed1997

Self-concept and body image of Turkish high school male athletes and nonathletes.

This study was conducted to determine the differences in self-concept and body image satisfaction and the relation between self-concept and body image among 174 Turkish high school male athletes and 174 nonathletes. The subjects were randomly selected from public high schools which represent middle socioeconomic status in Ankara. The Harter Self-Perception Profile for Adolescents and Berscheid, Walster, and Bohrnstedt's Body Image Questionnaire were administered to all participants. Significant differences were found in social acceptance, athletic competence, and physical appearance subscales of self-concept (p < .05), as well as in mean body image satisfaction among both groups (p < .05). There were also significant correlations between subscales of self-concept and body image for athletes and nonathletes.

Adolescent↗
PubMedDate not supplied

[Effectiveness of an educational intervention in improving the self concept of second to sixth grade students].

This study evaluated the effectiveness of an intervention in improving the general, academic, physical and social self-concepts of 2nd to 6th grade students. The activities were carried out by the teachers during the 1992-93 school year. A questionnaire was completed by 271 students of the experimental school and by 467 students of the control school, both before and after the intervention. The multiple regression analyses showed important adjusted gains for self-concepts related to physical appearance, mathematics and relationship with parents. In all three cases, students with the largest deficit benefitted most from the intervention. This study shows that it is possible to improve self-concept and to do so through an intervention carried out in the school environment. This double finding is important to the promotion of psycho-social adaptation since self-concept is an important determinant and since few interventions have reached similar objectives.

Body Image↗
PubMed1998

Structure, stability, and development of young children's self-concepts: a multicohort-multioccasion study.

A new, individual administration procedure for assessing multiple dimensions of self-concept for young children 5-8 years of age (Marsh, Craven, & Debus) was the basis of this study. We expanded this application in a multicohort-multioccasion (MCMO) study that provides simultaneous multicohort comparisons (cross-sectional comparisons of different age cohorts) and longitudinal comparisons of the same children on multiple occasions. There was reasonable support for predictions that reliability, stability, factor structure, and the distinctiveness of the SDQ factors would improve with age (a between-group age cohort comparison) and from 1 year to the next (a longitudinal comparison), and that small gender differences were reasonably stable over age. Consistent with the proposal that children's self-perceptions become more realistic with age, Time 1 (T1) teacher ratings were more highly correlated with student self-ratings at T2 than T1 and contributed to the prediction of T2 self-concept beyond effects mediated by T1 self-concepts. The results support and expand the surprisingly good support for the multidimensionality of self-concept responses for very young children using this procedure.

Age Factors↗
PubMed1998

Predictors of fecundability and conception waits among the Dogon of Mali.

Surprisingly little is known about the mechanisms that underlie variation in female fertility in humans. Data on this topic are nonetheless vital to a number of pragmatic and theoretical enterprises, including population planning, infertility treatment and prevention, and evolutionary ecology. Here we study female fertility by focusing on one component of the interbirth interval: the waiting time to conception during menstrual cycling. Our study population is a Dogon village of 460 people in Mali, West Africa. This population is pronatalist and noncontracepting. In accordance with animist beliefs, the women spend five nights sleeping at a menstrual hut during menses. By censusing the women present at the menstrual huts in the study village on each of 736 consecutive nights, we were able to monitor women's conception waits prospectively. Hormonal profiles confirm the accuracy of the data on conception waits obtained from the menstrual hut census (Strassmann [1996], Behavioral Ecology 7:304-315). Using survival analysis, we identified significant predictors of the waiting time to conception: wife's age (years), husband's age (< 35, 35-49, > 49 years), marital duration (years), gravidity (number of prior pregnancies), and breast-feeding status. Additional variables were not significant, including duration of postpartum amenorrhea, sex of the last child, nutritional status, economic status, polygyny, and marital status (fiancée vs. married). We fit both continuous and discrete time survival models, but the former appeared to be a better choice for these data.

Adolescent↗
PubMed2000

Carrier testing in fragile X syndrome: effect on self-concept.

The purpose of the study was to explore self-concept in women at risk for inheriting the fragile X mutation. Time 1 measures were obtained prior to carrier testing and Time 2 measures were collected approximately 5 months after learning carrier status. The sample consisted of 42 women from 17 families. Measures included the Tennessee Self-Concept Scale (TSCS), the fragile X Visual Analog Scale (VAS), and a structured interview. The TSCS provided a global measure of self-concept and the fragile X VAS and structured interview provided a contextual measure of self related to carrier status. Results indicated that there were no differences initially between carriers and noncarriers and no change from Time 1 to Time 2 on the TSCS. Analysis of the Time 1 fragile X VAS means for the total sample found a reduction in positive feelings about self. Analysis of the Time 2 fragile X VAS found that noncarriers reported improvement in feelings about self, with no change in feelings about self found in the carriers. Responses from the structured interview indicated that the feelings regarding self in the context of genetic testing are not related to global self-concept, but result from concerns regarding the implications of a positive carrier test for themselves and their families. This information highlights areas related to carrier testing that warrant further investigation and may ultimately result in modifications to the genetic counseling.

Adult↗
PubMedDate not supplied

qNMR--a versatile concept for the validation of natural product reference compounds.

The validation of reference compounds for natural products is a domain of the same physico-chemical methods that are used for their isolation, especially those techniques involving coupled high-resolution chromatography. Acknowledging the great problem of co-eluting impurities contained in the 'biogenetic cocktail' of a plant extract, there is a strong demand for non-chromatographic alternatives in the quality assessment of reference compounds. Because of this, the concept of qNMR is introduced as a versatile tool based on qualitative and quantitative 1H-NMR allowing the precise and simultaneous determination of both the compound content as well as the amount and nature of the impurities. As opposed to measuring carbons, 1H-NMR benefits from much higher sensitivity and is far more versatile for routine analysis with respect to time and cost. Since quantification of impurities is reliant upon their identification and, therefore, limited by knowledge about their structure, the concept emphasizes the high demand for qualitative reference dossiers including quality NMR data for profiling potential impurities which may be analogues, isomers, or degradation or oxidation products of the reference compounds. The qNMR concept is developed with focus on its potential in the certification and quality control of reference compounds. Taking into account published work in the field of quantitative NMR, selected natural products are analysed in order to elaborate suitable experimental parameters and to obtain preliminary validation data. The method is discussed with respect to sensitivity, precision and selectivity. Typical relative errors are found to be below 2% for the quantification of both the major analyte and the minor impurities even when the latter are contained at the 1% level only. Documentation of the conformity of signal integration and precision is based on measurements of a certified reference standard. Determination of the natural 13C isotope is suggested as an elegant method of validation because the content values could be reproduced with errors below 1%. The qNMR concept offers a rapid and efficient way to assess the purity of natural products in a single analytical step without the need of performing multiple analyses, while still offering the option to retain the substance. Thus, qNMR pays tribute to the increasing demands in reference compound certification, but also holds out the prospect of easy access to the valid characterisation of natural products tested in vitro or in vivo for their biological and pharmacological effects.

Biological Factors↗
PubMedDate not supplied

Time-resolved fluorometry (TRF)-based immunoassay concept for rapid and quantitative determination of biochemical myocardial infarction markers from whole blood, serum and plasma.

We report the development of a time-resolved fluorometry-based immunoassay concept for the rapid measurement of three cardiac markers from whole blood, serum or plasma. Using a universal all-in-one (AIO) dry reagent concept, all the analyte specific reagents are built into a single microtire well, to which an identical assay protocol is applied. Addition of 5-20 microL sample (whole blood, serum or plasma) together with a universal buffer initiates the reaction, which is brought close to equilibrium in 15 min. After the wash step the Eu chelate-derived signal is measured directly from the dried surface. Application of this concept to the three cardiac markers illustrates its ability to provide rapid, highly sensitive and fully quantitative results over a large dynamic range with good reproducibility. Such a performance, especially when using whole blood specimens, is largely a consequence of the inherently fluorescent and stable Eu-chelate employed in the system. Correlation to commercial assays was excellent for all three analytes, as was between-sample matrix correlation using the AIO assays. The presented assay concept enabling a simple automation is particularly suited for point-of-care applications, where the performance characteristics are fully comparable to state-of-the-art central laboratory immunoassays.

Biomarkers↗
PubMed1999

Homology--history of a concept.

The concept of homology is traceable to Aristotle, but Belon's comparison in 1555 of a human skeleton with that of a bird expressed it overtly. Before the late 18th century, the dominant view of the pattern of organisms was the scala naturae--even Linnaeus with his divergent hierarchical classification did not necessarily see the resulting taxonomic pattern as a natural phenomenon. The divergent hierarchy, rather than the acceptance of phylogeny, was the necessary spur to discussion of homology and the concept of analogy. Lamarck, despite his proposal of evolution, attributed homology to his escalator naturae and analogy to convergent acquired characters. Significantly, it was the concept of serial homology that emerged at the end of the 18th century, although comparison between organisms became popular soon after, and was boosted by the famous Cuvier/Geoffroy Saint-Hilaire debate of the 1830s. The concepts of homology and analogy were well understood by the pre- (or anti-) evolutionary comparative anatomists before the general acceptance of phylogeny, and they were defined by Owen in 1843. The acceptance of evolution led to the idea that homology should be defined by common ancestry, and to the confusion between definition and explanation. The term 'homoplasy', introduced by Lankester in 1870, also arose from a phylogenetic explanation of homology.

Adaptation, Biological↗
PubMed2005

Reproductive endocrinology of wild female chimpanzees (Pan troglodytes schweinfurthii): methodological considerations and the role of hormones in sex and conception.

Fecal and urine samples were collected from 81 female East African chimpanzees (Pan troglodytes schweinfurthii) in three major study populations in Gombe National Park, Tanzania, and Budongo Forest Reserve and Kibale National Park, Uganda. In this study I evaluated issues related to sample storage and assay reliability, and used these methods to investigate the significance of ovarian hormone levels in terms of conception success and sexual behavior. Drying of feces proved to be an effective technique and resulted in hormonal concentrations that were significantly correlated with concentrations in frozen feces. Estimates of ovarian steroid production based on urine and fecal sampling were significantly correlated with each other. The ovarian cycle profiles obtained, which were aligned relative to sexual swelling detumescence, corroborate previous findings in wild west African chimpanzees [Deschner et al., Animal Behaviour 66:551-560, 2003] in suggesting that the fertile period is limited to the last week of tumescence, but that ovulatory timing is not as precise as previously thought. A comparison across cycles confirmed the hypothesis that higher ovarian steroid levels are associated with an increased probability of conception. Females that did conceive with relatively low hormone levels had poor reproductive outcomes. Sexual behavior was tied to the probability of conception both within and across cycles. Copulatory activity within cycles closely followed the estrogen profile and was timed to coincide, on average, with the peak fertile period of females. Further, rates of copulation were significantly higher during the fertile periods of cycles that led to conception than those that did not.

Animals↗
PubMed2005

Similar rhythms of seasonal conceptions in neural tube defects and schizophrenia: a hypothesis of oxidant stress and the photoperiod.

BACKGROUND: Numerous studies have found that people with schizophrenia tend to be born most often in late winter and least often in late summer. The same rhythm appears in the birth of children with neural tube defects (NTDs). In the northern hemisphere, both disorders thus show a conception peak in May-June and a trough around November-December. The senior author found the same May-June conception peak among left-handed American baseball players and the opposite effect (a November-December peak) among extreme right-handed players. A similar rhythm appeared with respect to characteristics related to artistic as opposed to scientific modes of thought. DISCUSSION: Schizophrenia has been proposed to involve a deficit in the establishment of lateral asymmetry, as does left-handedness. The artist-scientist dichotomy is also believed to involve cerebral dominance. Thus, the similarity of seasonal variation in month of conception between NTDs, schizophrenia, left-handedness, and artistic intuition suggests that these four conditions may share some factor affecting the cellular processes involved in both neural tube closure and asymmetry development during the early-fourth week, neural-fold stages of embryogenesis. We propose that maternal oxidant stress, which can rise with exposure to intense solar radiation, may interfere with both neural tube closure and asymmetry development. The June and December extremes of sunlight would thus explain the peak times of the seasonal fluctuations. Moreover, regardless of mechanisms, the parallel between the two conception rhythms suggests that the same periconceptional folate regimens found effective in preventing NTDs may also lower the risk of schizophrenia. This paper reviews some of the clinical and experimental evidence supporting this hypothesis.

Humans↗
PubMed2005

Hierarchical models for the probabilities of conception.

In the last thirty years, there has been considerable interest in finding better models to fit data for probabilities of conception. An important early model was proposed by Barrett and Marshall (1969) and extended by Schwartz, MacDonald and Heuchel (1980). Recently, researchers have further extended these models by adding covariates. However, the increasingly complicated models are challenging to analyze with frequentist methods such as the EM algorithm. Bayesian models are more feasible, and the computation can be done via Markov chain Monte Carlo (MCMC). We consider a Bayesian model with an effect for protected intercourse to analyze data from the California Women's Reproductive Health Study and assess the effects of water contaminants and hormones. There are two main contributions in the paper. (1) For protected intercourse, we propose modeling the ratios of daily conception probabilities with protected intercourse to corresponding daily conception probabilities with unprotected intercourse. Due to the small sample size of our data set, we assume the ratios are the same for each day but unknown. (2) We consider Bayesian analysis under a unimodality assumption where the probabilities of conception increase before ovulation and decrease after ovulation. Gibbs sampling is used for finding the Bayesian estimates. There is some evidence that the two covariates affect fecundability.

Bayes Theorem↗
PubMed2004

Increased rate of aneuploid embryos in young women with previous aneuploid conceptions.

OBJECTIVES: To determine whether a history of a previous aneuploid conception increases the rate of aneuploidy among women having preimplantation diagnosis (PGD). METHODS: Preimplantation embryos were tested for aneuploidy using FISH probes specific for chromosomes 13,15,16,17,18,21,22,X and Y. Using logistic regression to control for maternal age, we compared the rates of aneuploidy and other chromosome errors in 344 embryos from women having PGD because of a history of a previous aneuploid conception, 363 embryos from 42 women having PGD because of X-linked disorders and 1158 embryos from 135 women having PGD because of repeated in vitro fertilization failure. RESULTS: The frequency of aneuploidy differed significantly among patient groups for women younger than 35 (p = 0.003) but not for women older than 35. In women < 35, the rate of detected aneuploidy was 37.4% in the Aneuploid group, 20.9% in the X-linked group and 27.0% in the RIF group. (p = 0.0003 when the control groups are combined). The frequency of other chromosome abnormalities, as well as pregnancy and implantation rates, did not differ significantly among patient groups. CONCLUSIONS: This study suggests that a history of a trisomic pregnancy, whether or not it was a viable trisomy, is associated with an increased risk of another aneuploid conception at conception.

Adult↗
PubMedDate not supplied

What do category-specific semantic deficits tell us about the representation of lexical concepts?

A reassessment of category-specific semantic deficits in light of their contribution to a theory of the representation of lexical concepts is proposed. Two theories are examined: one, held by the majority of researchers in the field, claims that concepts are represented by sets of features; another, in contrast, claims that concepts are atomic representations. An analysis of category-specific semantic deficits in terms of inferential relations (of the meaning-postulates type) between atomic concepts is elaborated. It is argued that this theory can better account for the pattern of performance exhibited by patients with semantic deficits.

Cognition↗
PubMed2001

Conceptions of Ability and Achievement Goals in Physical Education: Comparisons of American and Chinese Students.

This study focused on comparisons of American and Chinese students in conceptions of ability and achievement goals in physical education. Three hundred eight American students and 371 Chinese students in 4th, 8th, and 11th grades completed questionnaires assessing their conceptions of ability and achievement goals. Results indicated that for both American and Chinese students, as they progressed through the grades they tended to develop a differentiated conception of ability and to become more ego-oriented. Achievement goals were related to conceptions of ability. Cultural differences were found in the two variables. The findings offer additional empirical support to the view that goal theory is relevant to physical education settings and that achievement-related cognitions vary as a function of children's age and cultural background. Copyright 2001 Academic Press.

Journal Article↗