Search PubMed⌕ Search

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.

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

At least 793 records · Page 44Linked to original sources
PubMed1999

The Big-Fish-Little-Pond Effect for Academic Self-Concept, Test Anxiety, and School Grades in Gifted Children.

This study reports data extending work by Marsh and colleagues on the "big-fish-little-pond effect" (BFLPE). The BFLPE hypothesizes that it is better for academic self-concept to be a big fish in a little pond (gifted student in regular reference group) than to be a small fish in a big pond (gifted student in gifted reference group). The BFLPE effect was examined with respect to academic self-concept, test anxiety, and school grades in a sample of 1020 gifted Israeli children participating in two different educational programs: (a) special homogeneous classes for the gifted and (b) regular mixed-ability classes. The central hypothesis, deduced from social comparison and reference group theory, was that academically talented students enrolled in special gifted classes will perceive their academic ability and chances for academic success less favorably compared to students in regular mixed-ability classes. These negative self-perceptions, in turn, will serve to deflate students' academic self-concept, elevate their levels of evaluative anxiety, and result in depressed school grades. A path-analytic model linking reference group, academic self-concept, evaluative anxiety, and school performance, was employed to test this conceptualization. Overall, the data lend additional support to reference group theory, with the big-fish-little-pond effect supported for all three variables tested. In addition, academic self-concept and test anxiety were observed to mediate the effects of reference group on school grades. Copyright 1999 Academic Press.

Journal Article↗
PubMed1999

Sport-caught fish consumption and conception delay in licensed Michigan anglers.

Between 1993 and 1995, we surveyed 4931 licensed anglers aged 17-34 years residing in 10 Michigan counties bordering a Great Lake. Responses were received from 1443 anglers and 844 of their partners. Lifetime sport-caught fish consumption was estimated as the number of sport-caught fish meals consumed in the previous 12 months times years since 1970 in which sport-caught fish were consumed. Analysis was restricted to currently married couples (n=626). Lifetime sport-caught fish consumption was categorized in men as 0 (14%); 1-114 (27%); 115-270 (30%); 271-1127 (29%) meals; and in women as 0 (28%); 1-54 (26%); 55-138 (27%); fand 139-1127 (19%) meals, respectively. Conception delay (ever having failed to conceive after 12 months of trying) was reported by 13% of both men and women. Among men, the unadjusted odds ratios (OR) for conception delay were 1.2, 1.3, and 2.0 across the three increasing levels of sport-caught fish consumption compared to none (trend test P=0.06). After adjustment for age, race, region of Michigan, household income, educational attainment, smoking, alcohol consumption, and partner's sport fish consumption, the OR for conception delay in men were 1.4, 1.8, and 2.8, respectively. In women, unadjusted OR for conception delay were 0.9, 1.0, and 1.4 with increasing sport-caught fish consumption (trend test P=0.35). With the same covariates and the sport-caught fish consumption of the woman's partner included in the model, the OR were 0.8, 0.8, and 1.0, respectively. These data suggest a modest association, in men only, of sport-caught fish consumption with risk of conception delay.

Adolescent↗
PubMed2001

A knowledge-based, concept-oriented view generation system for clinical data.

Information overload is a well-known problem for clinicians who must review large amounts of data in patient records. Concept-oriented views, which organize patient data around clinical concepts such as diagnostic strategies and therapeutic goals, may offer a solution to the problem of information overload. However, although concept-oriented views are desirable, they are difficult to create and maintain. We have developed a general-purpose, knowledge-based approach to the generation of concept-oriented views and have developed a system to test our approach. The system creates concept-oriented views through automated identification of relevant patient data. The knowledge in the system is represented by both a semantic network and rules. The key relevant data identification function is accomplished by a rule-based traversal of the semantic network. This paper focuses on the design and implementation of the system; an evaluation of the system is reported separately.

Artificial Intelligence↗
PubMed2000

The concept of the sentinel lymph node.

Lymphangiograms performed via direct cannulation of lymphatic ducts demonstrate drainage of the lymph into a specific lymph node center, the so-called SLN. Contrast materials such as lipiodol, injected directly into the tissue (e.g., tongue) can demonstrate the SLN. As the neoplastic cells can be carried through the lymphatic ducts, the SLN is the first filter in the lymphatic pathway, and the SLN is indeed the most likely regional node to harbor metastatic carcinoma. The results of these efforts challenged the surgical community worldwide to recognize the importance of the concept of SLN. This concept needs to be inexpensive and easily applied in daily practice. Recently, brilliant investigators have found that using "blue dye" and or radioactive tracers are a resourceful way in identifying SLN and have applied the benefits in their daily practice. Morton [15] using the "blue dye" and Krag [1] using radioactive tracers are pioneers in the application of these concepts in other malignant diseases. The SLN concept today is feasible to apply in the investigation, diagnosis, staging and treatment of almost all solid tumors in human pathology. Numerous elegant reports have proved the validation of the concept [2, 7-9, 11, 12, 16, 17, 20, 21, 26-28].

Coloring Agents↗
PubMed1976

A critical review of the 'neugliederung' concept in relation to the development of the vertebral column.

The literature on the early embryonic development of the vertebral column in various animal species was analyzed to evaluate so many unrelated or contradictory observations. The recurring problems are described. One of the first was the lack of correspondence between the metameric boundaries of the 'primitive vertebral bodies' arising from the somites and those of the adult vertebral bodies, as presumably shown by their relationship to the vertebral processes and spinal nerves. A century ago, Remak introduced the concept of 'Neugliederung', according to which the ultimate vertebral body boundaries are determined by a shift of a half segment in comparison with the earlier segment boundaries. Another question was about the nature of the structures the primitive segments give rise to (axial skeletal tissue and/or muscular tissue and/or nervous tissue), which led to the fundamental problem which system (skeleton or musculature) retains its segmentation. The observation of what was called the intervertebral fissure led to a far-reaching modification of the 'Neugliederung' concept, making a regrouping of parts of the primitive vertebral bodies both possible and probable. The functional necessity for the alternation of muscle and skeleton primordia was also assumed. Although the difference in rostro-caudal level between the boundaries of the somites and the definitive vertebral bodies, measured for instance in relation to the position of the intersegmental vessels, does not support a resegmentation of the vertebral column, because the somite is not a precursor of the adult vertebra, few authors have rejected this view. Subsequently, the discussion focussed on the problem of a) the animal species in which and b) the time at which the intervertebral fissure occurs, and the relationship of this fissure to the primitive vertebral cavity. Under the influence of comparative embryology, a number of authors concentrated mainly on identifying certain embryonic primordia as homologues of phylogenetic vertebral elements, and also on attempting to determine the recombination by which such elements could form a definitive vertebra. According to these authors, not only the vertebral bodies but also the arches and ribs undergo a 'Neugliederung'. Another variant of the 'Neugliederung' concept envisages a gradual shift of the original boundaries of the somites with respect to the transverse level of the definitive vertebrae with or without migration of cellular material. A critical consideration of the concepts at issue, and notably of the 'Neugliederung' concept, is presented. Certain phenomena held to be pillars of the 'Neugliederung' theory could not be confirmed. The functional interpretation of the resegmentation was also reduced to its proper proportions by the analysis. A development of the axial skeleton without resegmentation is just as conceivable in functional terms as one in which resegmentation occurs. A functionally meaningful relationship between muscles and skeletal elements is possible in both cases...

Animals↗
PubMed1996

On the changing concept of evolutionary population stability as a reflection of a changing point of view in the quantitative theory of evolution.

Eighteen different terms, currently employed to define various concepts of evolutionary stability in population dynamics are mentioned in this paper. Most of these terms are used in different connotations and even different meanings by different authors. On the other hand, different terms are often employed by different authors to define quite the same concept. Twenty-five years ago there was only one, well-defined, concept of stability, universally recognized in the field. In this paper I will try to relate the recent confusion, concerning concepts of population stability, with a more serious, though not that well-recognized, confusion in the modern analytic approach to population dynamics and quantitative evolution. Concepts of population stability will be examined in relation to each other on the one hand and, on the other hand, in relation to two dichotomies regarding the dynamic processes to which they correspond: Short-term versus long-term processes and processes concerning phenotypic changes versus process concerning genotypic changes. A hopefully more consistent use of the current terminology is suggested.

Biological Evolution↗
PubMed1994

A general formulation of the concept of independent action for the combined effects of agents.

Analysis schemes for the classification of synergism and antagonism for mixed agents operate on the discrepancies between observed and calculated results. As such they cannot be confirmed by experiments and therefore have to be tested in terms of mathematical and logical self-consistency. The concept of independent action is close to the literal meaning of the term "non-interaction". Since this concept does not depend on the mechanisms of actions nor on the type of effect scale used, it is suitable as one of the basic criterion for the definition of synergism and antagonism. A general mathematical framework of independent action is presented in this paper based on the concept of "relative effect" as used in the literature. The different equations for independent action currently used in various areas are shown to be manifestations of a general formula under different sets of boundary conditions, which are the natural limiting values of the effects of the corresponding system observed at low and at high doses of the agents. The framework can be generalized to the combined action of n-agents as well as to the interaction of an agent with itself. In addition, the differential form of the formula for independent action is derived. This framework of systematic definitions and derived equations enable a more in-depth study of the implications of the concept of independent action and its relation to other concepts of non-interaction.

Animals↗
PubMed2006

Concerning the use of Western medical terms to represent traditional Chinese medical concepts.

This paper strongly rejects the notion that the use of biomedical terms to represent traditional Chinese medical concepts is helpful to the internationalization of Chinese medicine. It further argues that this practice destroys the integrity and independence of Chinese medical concepts. Taking the term fēng huo yan as an example, it shows that the biomedical term "acute conjunctivitis" often suggested as the translation for this term is unsatisfactory, because (1) the clinical reference is not identical, (2) it introduces the concepts of "conjunctiva" and "inflammation" , which are not Chinese medical concepts, and (3) destroys the Chinese medical concepts "wind" and "fire" expressed in the Chinese, which reflect the way the disease is traditionally diagnosed and treated. While for English readers not familiar with Chinese medicine, "acute conjunctivitis" may be immediately intelligible, for those seeking a deep understanding of the subject, the literal translation (loan translation) "wind-fire eye" is much more helpful. This paper supports these arguments with numerous other examples.

Humans↗
PubMed1998

[Schizophrenia concepts in Soviet and Russian psychiatry].

Concepts of schizophrenia of the Soviet Russian school are presented. They are historically based upon the broad concepts of schizophrenia by Kraepelin and Bleuler. The relationships to the German concept of "Einheitspsychose" (unitary psychosis) is emphasized. Along with the discussion of correspondence to and differences with Western diagnostic systems (DSM, ICD) it is pointed out that the old Soviet system of classification extends to psychotic and also non-psychotic forms which in ICD-10 are not attributed to schizophrenia, but to other categories. Differential-diagnostic criteria of sluggish schizophrenia and neurosis, such as positive psychopathological symptoms, thought disturbances and changes in personality, will be delineated. Furthermore, recent developments in Russian psychiatry and modifications in Russian schizophrenia concepts will be exemplified by the concept of "psychic diathesis."

Cross-Cultural Comparison↗
PubMed2005

[Navigator concept. Optimizing the procedure for navigated total knee arthroplasty].

BACKGROUND: This study addresses work sharing during navigation-assisted total knee arthroplasty. Specifically, the concept is introduced of a "navigator" assistant who operates the navigation system during surgery while the surgeon concentrates on the primary steps of surgery. METHODS: In a prospective study of 40 total knee arthroplasties, one group of patients was treated using the navigator concept, a second group was treated using a conventional navigation setup, and a third group was treated with conventional internal and external alignment jigs. Surgery time and outcome parameters were compared. RESULTS: Results show a significant difference in surgery time between the three groups. The conventional and navigator concept groups showed similar surgery times; however, the navigation group without navigation concept exhibited longer surgery time. CONCLUSIONS: The navigator concept represents a highly effective principle to minimize surgery time needed during navigated total knee arthroplasty.

Algorithms↗
PubMed2007

The concepts of health and illness revisited.

Contemporary philosophy of health has been quite focused on the problem of determining the nature of the concepts of health, illness and disease from a scientific point of view. Some theorists claim and argue that these concepts are value-free and descriptive in the same sense as the concepts of atom, metal and rain are value-free and descriptive. To say that a person has a certain disease or that he or she is unhealthy is thus to objectively describe this person. On the other hand it certainly does not preclude an additional evaluation of the state of affairs as undesirable or bad. The basic scientific description and the evaluation are, however, two independent matters, according to this kind of theory. Other philosophers claim that the concept of health, together with the other medical concepts, is essentially value-laden. To establish that a person is healthy does not just entail some objective inspection and measurement. It presupposes also an evaluation of the general state of the person. A statement that he or she is healthy does not merely imply certain scientific facts regarding the person's body or mind but implies also a (positive) evaluation of the person's bodily and mental state. My task in this paper will be, first, to present the two principal rival types of theories and present what I take to be the main kind of reasoning by which we could assess these theories, and second, to present a deeper characterization of the principal rival theories of health and illness.

Attitude to Health↗
PubMed2005

The transformation of pharmacy concepts into building and organization.

OBJECTIVE OF THE STUDY: To explore the transformation of soft systems pharmacy concepts, with a special attention for pharmaceutical care, into hard systems properties of building and organization in community-based pharmacy practice in The Netherlands. METHOD: The applied methods for data-collection were interviews. The interviews were conducted at eight community pharmacies and four architectural firms. The central topics in the questionnaire were the building and the design process. The role of the architect was included in the questions for the pharmacist and the role of the pharmacist was included for the architect. The data were completed with simple observations, relevant documents, designs, photographic material and bills of quantities of best, ordinary and worst case practices. The data were used to address the coherence between pharmacy, building, and organization. MAIN OUTCOME MEASURE: The main outcome measure was the relevance for the objective of the study. Data-selection was based upon its supposed connection with the transformation of soft into hard systems. The main focus was on documentation, classification, and derivation that would improve the current understanding of the transformation of a pharmacy concept, especially pharmaceutical care, into building and organization. No further data-selection was made. RESULTS: The results show that architectural and organizational designs are actually used in the support of pharmaceutical care. A large variety of soft and hard systems were observed. However, pharmacists seem to agree on the use of the soft systems key words 'professional', 'accessible', and 'transparent', and also on the activities with respect to the provision of information and the cooperation with other disciplines. Although most observed transformations appear sensible, hard evidence provided by the pharmacist is very poor. The full impact of the implemented changes on pharmaceutical care or other concepts remains a mystery. There is a large variety of different hard properties in building and organization, reflecting different (but still related) soft pharmacy concepts. The connections in building and organization are regarded as the resources that make the provision of care possible. Observed were resources to support the provision of written and oral information, the conversation setting, and the cooperation with other professionals. Potentially important developments for pharmaceutical care are the separate consultation room, the multi-disciplinary health centre, and robotization. CONCLUSION: This study has revealed some of the interdisciplinary relations between pharmaceutical, architectural, and organizational designs in Dutch community pharmacy practices. From this study we can conclude that interventions in building and organization are actually used in the support of pharmacy concepts, specifically of pharmaceutical care. However, the hard evidence of supposed improvements remains poor and mostly absent.

Community Pharmacy Services↗
PubMed1994

Cumulative conception and live-birth rates after in vitro fertilization with and without the use of long, short, and ultrashort regimens of the gonadotropin-releasing hormone agonist buserelin.

OBJECTIVE: Our purpose was to compare cumulative conception and live-birth rates after in vitro fertilization with and without the use of the long, short, and ultrashort regimens of the gonadotropin-releasing hormone agonist buserelin. STUDY DESIGN: Life-table analysis of conception and live-birth rates in relation to ovarian stimulation regimen used in 2893 women who had one of five stimulation regimens exclusively throughout all treatment cycles, namely, human menopausal gonadotropin with or without clomiphene citrate; follicle-stimulating hormone with or without clomiphene citrate; and long, short, and ultrashort protocols of buserelin, plus follicle-stimulating hormone or human menopausal gonadotropin; and in an additional 347 women who had been administered both human menopausal gonadotropin and follicle-stimulating hormone with or without clomiphene citrate. RESULTS: The cumulative conception rate and cumulative live-birth rate were significantly higher in those women treated exclusively with the long buserelin regimen (59% and 55%, respectively, after three cycles) compared with those who only had human menopausal gonadotropin or follicle-stimulating hormone with or without clomiphene citrate (39% and 29%, respectively, after three cycles) (p = 0.001 and p = 0.0001) or compared with those who had only short or ultrashort buserelin regimens (22% and 17% after two cycles) (p = 0.0001 and p = 0.005). The pregnancy failure rate in patients on the long buserelin regimen was 22.4% (95% confidence interval 14.8% to 30.0%) compared with 33.3% (95% confidence interval 29.6% to 37.0%) in those who had human menopausal gonadotropin or follicle-stimulating hormone with or without clomiphene citrate (p = 0.03). When the probabilities of first conception and first live birth were examined by treatment regimen, after we allowed for the effects of age, cause of infertility, calendar year of treatment, and treatment cycle number (with a multiple logistic regression model), it was found that, relative to human menopausal gonadotropin or follicle-stimulating hormone with or without clomiphene citrate, the odds of conceiving with the long buserelin regimen was 1.63 (95% confidence interval 1.31 to 2.03) (p < 0.001) and the odds of a live birth was 1.97 (95% confidence interval 1.53 to 2.54) (p < 0.001). Similarly, relative to short or ultrashort buserelin the odds of conceiving with long bureselin was 1.88 (95% confidence interval 1.39 to 2.55) (p < 0.001) and the odds of a live birth was 1.79 (95% confidence interval 1.25 to 2.56) (p = 0.001). CONCLUSION: Pituitary desensitization with the long protocol of buserelin significantly increases the probabilities of conception and live birth after in vitro fertilization.

Adult↗
PubMed1992

As we may think: the concept space and medical hypertext.

Hypertext, a medium for presenting written material in a nonsequential manner, is gaining popularity as a format for medical text. The structure of "traditional" hypertext documents (hyperdocuments) includes author-created links among text segments. This structure poses challenge for those who create and maintain hyperdocuments, while reading them can introduce disorientation and cognitive overload. An alternative model is presented in which text segments are linked to the concepts which they contain and the concepts are linked to each other in a semantic network called the "Concept Space." The concepts and semantic links attempt to approximate potential topics of interest, allowing the reader to browse the hyperdocument in an individualized manner, rather than in an author-designated one. The concept space approach offers advantages for both the author and the reader.

Authorship↗
PubMed1994

Positive temporal sharp waves on EEG recordings of healthy neonates: a benign pattern of dysmaturity in pre-term infants at post-conceptional term ages.

One complete sleep cycle was selected in each of ninety-four 3 h EEG recordings on 52 healthy neonates from 29 to 43 weeks CA (28 pre-term (PT)/24 full-term (FT)); 51 who are neurodevelopmentally normal up to at least 18 months of age. Each recording was reviewed to identify positive temporal sharp waves (PTS). This wave form was compared to another commonly occurring wave form, temporal theta of prematurity (PT theta). 588 PTS and 626 PT theta observations were tabulated in terms of frequency, amplitude, morphology, left:right predominance, and sleep state at 6 post-conceptional age ranges up to term. Mean PTS for FT, PT and pre-term at post-conceptional term age (PTT) infants, respectively, were 1.5 +/- 0.85, 2.8 +/- 2.5, 2.0 +/- 1.6 per sleep cycle. PTS amplitudes (microV) were 59.7 +/- 23.5, 38.2 +/- 17.8, and 51.8 +/- 29.3. The peak incidence of PTS occurs at older post-conceptional ages than PT theta (r = 0.21, P = 0.0001). PTT infants had more PTS (chi 2 = 32.5, P = 0.001) than FT infants. Similar numbers and descriptions of PT theta were noted between neonatal groups at post-conceptional term ages. While pathological PTS waves have been described in FT neonates and infants (Chung and Clancy: Electroenceph. clin. Neurophysiol., 1991, 79: 256-263), benign PTS waves are also present on recordings of healthy pre-term and full-term neonates. PTS are electrographically similar to PT theta, but are more abundant at older post-conceptional ages in pre-term infants than full-term infants.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗
PubMed1993

An analysis of the concept "quality" as it relates to contemporary nursing care.

This analysis explores the applications and interpretations of the extensively used, but seldom defined, concept of "quality" as it relates to contemporary nursing care. This study employed an inductive approach to describe and explain the use and meaning of the concept; data generated from the literature were also analysed to identify the predominant attributes or characteristics of the concept quality associated with health care. The analysis yielded data from which modes of conceiving, describing and explaining the concept "quality nursing care" could be induced and grounded theory could be generated. Quality emerged as a complex, multi-dimensional concept requiring further analysis and clarification. Unaware of, or undeterred by the conceptual confusion, quality care continues to be assured, controlled, evaluated and managed in the Health Service today.

Humans↗
PubMed1987

The chance of spontaneous conception for the infertile couple referred to an academic clinic for reproductive endocrinology and fertility in The Netherlands.

892 infertile couples were studied retrospectively over a 4 year and 7 month period for their chance of spontaneous conception after first attendance at the clinic. The Kaplan-Meier method was used for all calculations. Most of the spontaneous conceptions took place within two years. As the age of the female patient increased, beginning at age 30, the cumulative spontaneous conception rate decreased. The same was true for the duration of infertility beginning at 4.5 years. The influence of the latter was more important. The cumulative conception rate was not influenced by whether the infertility was primary or secondary. Patients referred by a general physician had a better chance of achieving spontaneous conception than patients referred by a gynaecologist. It is concluded that time plays a significant role in the achievement of pregnancies in our clinic, but should no longer be relied upon two years after entering the clinic.

Adolescent↗
PubMed1995

Course and outcome of IVF pregnancies and spontaneous conceptions within an IVF setting.

The study determines mortality and morbidity levels during pregnancy and the perinatal period in those conceiving through IVF in the Republic of Ireland in comparison with other parts of the world and a peer infertile group conceiving spontaneously whilst on the IVF clinic books. Six hundred and sixty couples had 187 IVF pregnancies from whom 220 babies were born to 151 deliveries. There were also 78 spontaneous conceptions which produced 78 offspring from 73 deliveries. The majority had trouble free pregnancies. The incidence of all complications was less than has been reported elsewhere. Of the IVF group, 16.5% aborted completed as did 5% of the spontaneous conceptions. A further 7% and 3.8%, respectively, aborted one sac of a multiple pregnancy. Of the IVF deliveries, 35.8% were multiple as were 6.8% of the spontaneous conceptions. Higher order multiple presence detrimentally influenced delivery mode, gestational age and birth weights in the IVF group. Of IVF patients, 55.7% were section deliveries as were 10.9% of the spontaneous conceptions. Incidence of IVF-group significant congenital abnormality was 1.8%. The perinatal mortality rate was 4.2 per 1000 births. This series suggests the final take-home baby outlook of 81% from conception by IVF is not as poor as previously portrayed. However, attention should be given to abortion, section and multiple pregnancy rates.

Adult↗