SEARCH · Search PubMed

Results for “conception”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 379 records · Page 21Linked to original sources

PubMed2006

Teenage conceptions, abortions, and births in England, 1994-2003, and the national teenage pregnancy strategy.

BACKGROUND: The aim of this study was to quantify the change in the number of conceptions and abortions among women younger than 18 years in England in relation to the government's national teenage pregnancy strategy. METHODS: We undertook geographic analysis of data for 148 top-tier local authority areas. The main outcomes were changes in under-18 conceptions, abortions, and births between the 5-year period before implementation of the strategy (1994-98) and the period immediately after implementation (1999-2003). FINDINGS: The number of teenage conceptions peaked in 1998, then declined after the implementation in 1999 of the teenage pregnancy strategy. Under-18 conception rates fell by an average of 2.0% (95% CI 1.8 to 2.2) per year between 1998 and 2003, below the rate needed to achieve the target of 50% reduction by 2010. The net change between 1994-98 and 1999-2003 was a fall in conceptions of 3.2% (2.6 to 3.9) or 1.4 per 1000 women aged 15-17 years, a rise in abortions of 7.5% (6.5 to 8.6) or 1.4 per 1000, and a fall in births of 10.6% (9.9 to 11.3) or 2.8 per 1000. The change in the number of conceptions was greater in deprived and more rural areas, and in those with lower educational attainment. The change was greater in areas where services and access to them were poorer, but greater where more strategy-related resources had been targeted. INTERPRETATION: The decline in under-18 conception and birth rates since 1998 and evidence that the declines have been greatest in areas receiving higher amounts of strategy-related funding provides limited evidence of the effect of England's national teenage pregnancy strategy. The full effect of local prevention will be clear only with longer observation, and substantial further progress is needed to remedy England's historically poor international position in teenage conceptions.

Abortion, Induced↗

PubMed2004

Different preferences for prenatal diagnosis in pregnancies following assisted reproduction versus spontaneous conception.

The uptake of prenatal diagnosis in 436 singleton and 146 twin pregnancies following assisted reproduction was compared with a matched group of spontaneous conceptions. The first and second trimester ultrasound examination included target fetal anatomic evaluation and screening by specific markers described for fetal aneuploidy. Women with assisted conception attended significantly more often for first trimester prenatal diagnosis (57.9 versus 34.9%, P < 0.01), but had fewer examinations in the early second trimester at 15-18 weeks (37.8 versus 48.8%, P < 0.01) than those with spontaneous conception. Screen positive results of 6.5 and 6.9% for first trimester examination and 6.0 and 7.3% for second trimester examination were found in assisted conceptions and controls respectively. A significantly higher rate of invasive prenatal diagnosis was observed in the second trimester for spontaneous conceptions, 20.0 versus 11.8% (P < 0.01) compared with assisted conceptions. This was attributed to the higher rate of invasive procedures in advanced maternal age >/=35 years of 40.7 versus 28.6% (P = 0.01) in spontaneous and assisted conceptions respectively. With the purpose of avoiding invasive testing, women with assisted conception were more likely to use the results of the ultrasound examination to guide their final decision about invasive testing, rather than undergo genetic amniocentesis as a first option.

Amniocentesis↗

PubMed1995

Presence, completeness, and accuracy of main concepts in the connected speech of non-brain-damaged adults and adults with aphasia.

A standard rule-based system was used to evaluate the presence, accuracy, and completeness of main concepts in the connected speech of 20 non-brain-damaged adults and 20 adults with aphasia. Main concepts form a skeletal outline of the most important information (or "gist") in a message. The interjudge and intrajudge reliability of the main concept scoring system and the test-retest stability of scores were acceptable. The non-brain-damaged group produced significantly more Accurate/complete main concepts, and significantly fewer Accurate/incomplete, Inaccurate, and Absent main concepts than the group with aphasia. However, when the performance of individual subjects was evaluated, what best discriminated the performance of subjects with aphasia from that of non-brain-damaged subjects was not the number of main concepts they failed to mention but the accuracy and completeness of the main concepts they did produce. Measures of main concept production may be a clinically useful complement to other measures of communicative informativeness and efficiency.

Aged↗

PubMed2000

Peak occurrence of female sexual initiation predicts day of conception in rhesus monkeys (Macaca mulatta).

The present study investigated whether peaks in female sexual initiation could accurately predict conception in group-living female rhesus monkeys. Behavioral observations, 4 or 5 days per week in large, stable, social groups of monkeys, provided frequencies of female initiation of proximity, sexual solicitation, mounts, and ejaculations. Since a preovulatory peak in female sexual initiation is likely linked to the preovulatory oestradiol surge, we used the third day after a peak in behavior as the behavioral estimate of conception date. For each pregnancy, an independent estimate of conception date was derived from ultrasound determination of fetal length. Estimates of conception based on female initiation of proximity with adult males were accurate for more than 90% of pregnancies, whereas observation of ejaculations by males predicted conception in fewer than 60% of pregnancies. Behavioral and ultrasound estimates of conception date were highly correlated and differed by less than I day on average. Accordingly, predictions of delivery date based on behavioral estimates of conception date were as accurate as those based on ultrasound-derived estimates. These data suggest that female-initiated sexual behavior can be used in rhesus monkeys as a practical, non-invasive tool for producing timed matings in social groups of monkeys, providing accurate estimates of conception date, gestational age, and predicted date of birth.

Animals↗

PubMed2004

Visualization for constructing and sharing geo-scientific concepts.

Representations of scientific knowledge must reflect the dynamic nature of knowledge construction and the evolving networks of relations between scientific concepts. In this article, we describe initial work toward dynamic, visual methods and tools that support the construction, communication, revision, and application of scientific knowledge. Specifically, we focus on tools to capture and explore the concepts that underlie collaborative science activities, with examples drawn from the domain of human-environment interaction. These tools help individual researchers describe the process of knowledge construction while enabling teams of collaborators to synthesize common concepts. Our visualization approach links geographic visualization techniques with concept-mapping tools and allows the knowledge structures that result to be shared through a Web portal that helps scientists work collectively to advance their understanding. Our integration of geovisualization and knowledge representation methods emphasizes the process through which abstract concepts can be contextualized by the data, methods, people, and perspectives that produced them. This contextualization is a critical component of a knowledge structure, without which much of the meaning that guides the sharing of concepts is lost. By using the tools we describe here, human-environment scientists are given a visual means to build concepts from data (individually and collectively) and to connect these concepts to each other at appropriate levels of abstraction.

Environment↗

PubMed2006

Concepts underlying outcome measures in studies of consultations in general practice.

OBJECTIVE: To give an overview of the concepts used to describe and evaluate the outcome of general practice consultations. METHOD: A literature study was undertaken. Among 101 articles relevant to the subject 35 were chosen to illustrate the concepts found. RESULT: The following concepts were found: disease control, patient compliance, efficacy, symptom relief, enablement, general health, and patient satisfaction. The first three concepts encourage objective measurement while the following four concern the patient's subjective assessment. Methods naturally linked to the respective concepts are briefly described. DISCUSSION: The concepts reflect very diverse aspects of general practice. Some of the concepts come from other domains of research, while others have been developed within general practice. Disease is not exclusively in focus. The experience, competence, and life situation of the patient are as well dealt with as they should be in accordance with a patient-centred profession. However, the concepts spring from the researchers' ideas about what is important to patients. The patients' priorities were not sought.

Efficiency, Organizational↗

PubMed2003

Women's interest in GP-initiated pre-conception counselling in The Netherlands.

BACKGROUND: Pre-conception counselling has the potential to reduce pregnancy complications and congenital disorders. The timing of counselling, before conception, is crucial to maximize the benefit. As many couples are unaware of their risk status and the fact that the first period of pregnancy is crucial, they do not seek information before pregnancy occurs. To reach couples with timely information, it seems that a health care worker needs to take the initiative. In The Netherlands, the GP is in an ideal position to offer pre-conception counselling. OBJECTIVE: The aim of this study was to determine the interest of women aged 18-40 in pre-conception counselling if this is offered to them by their own GP. METHOD: A cohort of women (n = 1206) received a personal letter from their own GP with an offer of pre-conception counselling. The women were requested to fill in a reply form, indicating if they were interested, might be interested (if they decided to become pregnant) or were not interested in an invitation for pre-conception counselling. When interested, they were asked to give an indication as to when they were planning a pregnancy. Women who were not interested were requested to give a reason. RESULTS: Almost 70% of the women returned the reply form. Up to the age of 29 years, at least 80% of the respondents were interested or might be interested should they decide to have children. Most women, especially the younger women, do not know exactly when they wish to become pregnant. Regardless of age, >70% of the respondents were interested. Only 11% of the respondents indicated specifically that they were not interested in advice. CONCLUSION: Women are interested in GP-initiated pre-conception counselling. Further research is needed to assess the effect of programmed and systematic pre-conception counselling, offered by GPs, on pregnancy outcome and the health of the children. A randomized controlled trial to assess these effects currently is being conducted at the Department of General Practice in Leiden.

Adolescent↗

PubMed1995

Effects of caffeine consumption on delayed conception.

The authors examined the effects of caffeine consumption on waiting time to conception in the Reproductive Health Study, a retrospective study of 1,430 non-contracepting, parous women interviewed between July 1989 and June 1990 at Fishkill, New York, and Burlington, Vermont. Information was obtained on 2,501 pregnancies since 1980. Women's reported consumption of caffeinated beverages during the first month of pregnancy was used to estimate daily caffeine intake, which was categorized as none, 1-150, 151-300, and > or = 301 mg. Information on delayed conception was analyzed as a dichotomous variable (< or = 12 months delay vs. > 12 months delay), and the per cycle probability of conception (fecundability) was estimated using waiting time to conception as a continuous variable. Odds ratios of delayed conception and fecundability ratios adjusted for age, parity, smoking, last contraceptive used, infertility history, and race, were estimated by logistic regression and Cox proportional hazard models, respectively. Women who did not smoke and who consumed no caffeine were used as a reference group. The adjusted odds ratio of delayed conception for more than one year was not increased among women who consumed < or = 300 mg of caffeine daily. However, the odds ratio (OR) was 2.65 (95% confidence interval (CI) 1.38-5.07) among nonsmokers who consumed > or = 301 mg of caffeine daily. Although smoking per se was associated with a significant increased risk of delayed conception (OR = 1.77, 95% CI 1.33-2.37), no effect of high caffeine consumption was observed among women who smoked. Fecundability was reduced among nonsmokers who consumed more than 300 mg caffeine daily (fecundability ratio = 0.74, 95% CI 0.59-0.92). Smoking reduced the fecundability ratio, but the authors observed no effect of caffeine consumption on fecundability among women who smoked. Other studies provide biologic plausibility for these findings. The authors conclude that high levels of caffeine consumption may result in delayed conception among women who do not smoke cigarettes.

Adult↗

PubMed2004

Strength training can have unexpected effects on the self-concept of children with cerebral palsy.

PURPOSE: This study was designed to evaluate the effect of a home-based progressive resistance strength-training program on the self-concept of children with cerebral palsy. METHODS: A randomized, controlled trial was used to evaluate the effects of a six-week strength-training program on self-concept immediately after completion of the program (week six) and at a follow-up session held 18 weeks after the initial assessment. Seventeen children [eight boys, nine girls; mean age 12.1 years (SD 2.5)] with spastic diplegic cerebral palsy were recruited. Participants in the experimental group completed a home-based progressive resistance strength-training program using three exercises to strengthen the major support muscles of the lower limb. Participants in the control group undertook their normal daily activities. Self-concept was measured by the Self-Perception Profile for Children. RESULTS: Overall, the self-concept of both groups was positive at baseline and at six and 18 weeks. However, compared with controls, the experimental group showed decreased self-concept in the domain of scholastic competence and a trend for a decrease in social acceptance at six weeks. At follow-up, the experimental group had reduced self-concept in the domains of scholastic competence and social acceptance compared with the control group. CONCLUSION: These unexpected results suggest that participation in a relatively short home-based strength-training program may have an inhibitory effect on the self-concept of children with cerebral palsy. Despite the inhibitory effect, self-concept in the experimental group remained positive after strength training, suggesting that clinicians should not be overly concerned about the psychological effects of the intervention.

Journal Article↗

PubMed2005

Concepts of recovery: competing or complementary?

PURPOSE OF REVIEW: Within the last 5 years, concepts of recovery have taken center stage in psychiatry as the overarching goal of mental health services. In the course of this shift towards recovery, clinicians and consumers (and many others) have struggled to make the concept of recovery both measurable and meaningful. The clinical concept of recovery has focused upon the remission of symptoms and restoration of functioning. A rehabilitation model of recovery has been a more subjective and consumer-oriented concept that focuses on the full lives that are lived within the context of enduring disability. RECENT FINDINGS: A review of the literature addressing the concepts of recovery over the last 2 years demonstrates that authors are rarely explicit about the perspective of recovery from which they are writing. Almost all of the representative papers, however, struggled with how best to define, measure and validate recovery in its broadest terms. Several authors reviewed the history of recovery and offered conceptual discussions of either their first-person experiences or implications for mental health practice. Other authors, regardless of their perspective on recovery, sought to more concretely define criteria for recovery, for the purposes of recovery measure development or more rigorous research of the concept. SUMMARY: As authors struggle to reconcile these often competing concepts of recovery, we suggest that both concepts are useful for different purposes and populations and that the synthesis of the two will offer a broader perspective on life with, after, or despite mental illness.

Journal Article↗

PubMed2001

Meeting medical terminology needs--the Ontology-Enhanced Medical Concept Mapper.

This paper describes the development and testing of the Medical Concept Mapper, a tool designed to facilitate access to online medical information sources by providing users with appropriate medical search terms for their personal queries. Our system is valuable for patients whose knowledge of medical vocabularies is inadequate to find the desired information, and for medical experts who search for information outside their field of expertise. The Medical Concept Mapper maps synonyms and semantically related concepts to a user's query. The system is unique because it integrates our natural language processing tool, i.e., the Arizona (AZ) Noun Phraser, with human-created ontologies, the Unified Medical Language System (UMLS) and WordNet, and our computer generated Concept Space, into one system. Our unique contribution results from combining the UMLS Semantic Net with Concept Space in our deep semantic parsing (DSP) algorithm. This algorithm establishes a medical query context based on the UMLS Semantic Net, which allows Concept Space terms to be filtered so as to isolate related terms relevant to the query. We performed two user studies in which Medical Concept Mapper terms were compared against human experts' terms. We conclude that the AZ Noun Phraser is well suited to extract medical phrases from user queries, that WordNet is not well suited to provide strictly medical synonyms, that the UMLS Metathesaurus is well suited to provide medical synonyms, and that Concept Space is well suited to provide related medical terms, especially when these terms are limited by our DSP algorithm.

Algorithms↗

PubMed2004

Retrieval for color artistry concepts.

This paper presents a work on the retrieval of artworks for color artistry concepts. First we affirm the view that the Query-by-Example paradigm fundamental to the current content-based retrieval systems is able to extend only limited usefulness. We then propose a concept-based retrieval engine based on the generative grammar of elemental concepts methodology. In the latter, the language by which color artistry concepts are communicated in artworks is used to operate semantic searches. The color artistry language is explicated into elemental concepts and the associated generative grammar. The elemental concepts are used to index the artworks, while the generative grammar is used to facilitate post-coordinate expression of color artistry concept queries by using the elemental concepts.

Abstracting and Indexing↗

PubMed2006

Operationalizing the concept of resilience in child neglect: case study research.

BACKGROUND: There is a considerable amount of interest in resilience as a concept for child care and protection practice. This paper describes an exploratory project that drew on a set of case studies to explore the extent to which the concept of resilience can be operationalized for use with neglected children in the context of statutory social work. METHOD: The study was carried out within a local authority in Scotland and focused on the value of the concept as an aid to assessment and planning. The study built on a published workbook that provides a structure for the assessment of potential areas of resilience and gives detailed suggestions for intervention in six domains of a child's life. Eight neglected children aged between five and 11 were recruited. Six training days on the concept were held. Questionnaires were used to gather information about the theoretical frameworks already being used. At the end of the study, semi-structured interviews were carried out with the social workers about the value of the concept. Assessment reports completed before and after the training were analysed. RESULTS: Findings indicated that participants were familiar with the concept of resilience and that the training helped enhance their understanding of the concept. Training assisted with the provision of a more structured approach to assessment and planning. Respondents reported that the approach enhanced their knowledge of the child and they were able to identify areas for development in the six domains. CONCLUSION: The study indicated that the concept of resilience can be operationalized for use with neglected children. Further, the case studies raised the issue of the extent to which the need for a secure base underpins other domains. The domain of positive values was also highlighted as an important area for further exploration.

Adaptation, Psychological↗

PubMed2006

Estimation of the day-specific probabilities of conception: current state of the knowledge and the relevance for epidemiological research.

Conception, as defined by the fertilisation of an ovum by a sperm, marks the beginning of human development. Currently, a biomarker of conception is not available; as conception occurs shortly after ovulation, the latter can be used as a proxy for the time of conception. In the absence of serial ultrasound examinations, ovulation cannot be readily visualised leaving researchers to rely on proxy measures of ovulation that are subject to error. The most commonly used proxy measures include: charting basal body temperature, monitoring cervical mucus, and measuring urinary metabolites of oestradiol and luteinising hormone. Establishing the timing of the ovulation and the fertile window has practical utility in that it will assist couples in appropriately timing intercourse to achieve or avoid pregnancy. Identifying the likely day of conception is clinically relevant because it has the potential to facilitate more accurate pregnancy dating, thereby reducing the iatrogenic risks associated with uncertain gestation. Using data from prospective studies of couples attempting to conceive, several researchers have developed models for estimating the day-specific probabilities of conception. Elucidating these will allow researchers to more accurately estimate the day of conception, thus spawning research initiatives that will expand our current limited knowledge about the effect of exposures at critical periconceptional windows. While basal body temperature charting and cervical mucus monitoring have been used with success in field-based studies for many years, recent advances in science and technology have made it possible for women to get instant feedback regarding their daily fertility status by monitoring urinary metabolites of reproductive hormones in the privacy of their own homes. Not only are innovations such as luteinising hormone test kits and digital fertility monitors likely to increase study compliance and participation rates, they provide valuable prospective data that can be used in epidemiological research. Although we have made great strides in estimating the timing and length of the fertile window, more work is needed to elucidate the day-specific probabilities of conception using proxy measures of ovulation that are inherently subject to error. Modelling approaches that incorporate the use of multiple markers of ovulation offer great promise to fill these important data gaps.

Biomarkers↗

PubMed2001

The species concept for prokaryotes.

The species concept is a recurrent controversial issue that preoccupies philosophers as well as biologists of all disciplines. Prokaryotic species concept has its own history and results from a series of empirical improvements parallel to the development of the techniques of analysis. Among the microbial taxonomists, there is general agreement that the species concept currently in use is useful, pragmatic and universally applicable within the prokaryotic world. However, this empirically designed concept is not encompassed by any of the, at least, 22 concepts described for eukaryotes. The species could be described as 'a monophyletic and genomically coherent cluster of individual organisms that show a high degree of overall similarity in many independent characteristics, and is diagnosable by a discriminative phenotypic property'. We suggest to refer it as a phylo-phenetic species concept. Here, we discuss the validity of the concept in use which we believe is more pragmatic in comparison with those concepts described for eukaryotes.

Bacteria↗

PubMed2006

A survey of edentulous patient preference among different denture esthetic concepts.

STATEMENT OF PROBLEM: Despite the fact that solutions to functional problems are available, successfully restoring the appearance of an edentulous patient remains a challenge. PURPOSE: The aim of this survey was to determine if edentulous respondents could differentiate among three denture esthetic concepts and if there was an overall preference among the three. MATERIALS AND METHODS: Six edentulous test subjects were selected based on age and smile criteria. One wax tooth arrangement was completed according to each of the three esthetic concepts for a total of three wax tooth arrangements per test subject. The three esthetic concepts followed were natural, supernormal, and denture look. Standardized full-face digital photographs were made of each arrangement (three) during maximum smile for each subject (six). These 18 photographs were included in a questionnaire. Respondents were asked questions about their preference among the three randomly ordered concept photographs for each of the six subjects. A total of 147 completed questionnaires were analyzed. RESULTS: Ninety-six percent of respondents were able to differentiate among the three esthetic denture concepts. Natural tooth arrangements were preferred by 55% of the respondents, supernormal tooth arrangements were preferred by 19%, and the denture look arrangements were preferred by 26%. CONCLUSION: Within the limitations of this survey, the questionnaire respondents differentiated between the three esthetic denture concepts. The tooth arrangement most closely resembling the anatomical average was selected by 55% of the respondents. Preference for a particular concept changed when responses to each test subject set were considered individually. Demographic factors do not significantly affect patient preference. CLINICAL SIGNIFICANCE: Three esthetic concepts for complete denture construction have been differentiated. Questionnaire respondents preferred appearances that are far from the anatomical average 45% of the time.

Adult↗

PubMed2004

Neurological sequelae in twins born after assisted conception: controlled national cohort study.

OBJECTIVE: To compare neurological sequelae in twins born after assisted conception with singletons after assisted conception and naturally conceived twins and to assess neurological sequelae in children conceived after in vitro fertilisation (IVF) compared with intracytoplasmic sperm injection (ICSI). DESIGN: Controlled, national register based, cohort study. PARTICIPANTS: Twins (n = 3393) and singletons (n = 5130) conceived by using assisted reproductive technologies and naturally conceived twins (n = 10 239) born in Denmark between 1995 and 2000. The children's age at time of follow up was 2-7 years. DATA SOURCES: Children were identified by cross linkage of the national medical birth registry and the national registry for in vitro fertilisation. Neurological and psychiatric diagnoses were retrieved from the national patients' registry and the Danish psychiatric central registry. MAIN OUTCOME MEASURES: Neurological sequelae, defined as cerebral palsy, mental retardation, severe mental developmental disturbances, and retarded psychomotor development. Further we made separate analyses on the specific cerebral palsy diagnosis. RESULTS: The crude prevalence rates per 1000 of neurological sequelae in twins and singletons after assisted conception and in naturally conceived twins were 8.8, 8.2, and 9.6, and of cerebral palsy 3.2, 2.5, and 4.0, respectively. In twins after assisted conception compared with control twins, the odds ratios of neurological sequelae and specifically of cerebral palsy, adjusted for child sex and year of birth, were 0.9 (95% confidence interval 0.6 to 1.4) and 0.8 (0.4 to 1.6), respectively. The corresponding odds ratios for twins after assisted conception compared with singletons after assisted conception were 1.1 (0.7 to 1.7) for neurological sequelae and 1.3 (0.6 to 2.9) for cerebral palsy. The odds ratio of neurological sequelae in children conceived by ICSI was 0.9 (0.5 to 1.7) nu children conceived by IVF. CONCLUSIONS: Twins from assisted conception have a similar risk of neurological sequelae as their naturally conceived peers and singletons from assisted conception. Children born after ICSI have the same risk of neurological sequelae as children born after IVF.

Cohort Studies↗

PubMed1976

A behavioral technology for producing concept formation in university students.

Three experiments analyzed the effectiveness of a textbook incorporating "concept programming" in producing concept formation in university students. The concept programming portion of each lesson requires students to determine which concept is illustrated by each of 20 short fictional stories about everyday behavioral situations. The stories are selected to illustrate and contrast the concepts of that lesson. Student responses are heavily prompted during the initial stories of each lesson. The first experiment demonstrated that students generalize to entirely novel examples from the examples in the textbook. The second experiment demonstrated that the concept programming portion of the textbook is a critical component in producing generalization. The third experiment demonstrated that the amount of concept formation produced by the concept programmed textbook is greater than that produced by a widely used standard textbook.

Journal Article↗