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PubMed1981

The effect of scrotal circumference, sperm motility and morphology in the ram on conception rates and lambing percentage in the ewe.

Ten Suffolk and ten Lincoln yearling rams were examined for breeding soundness. Semen was evaluated, and the scrotal circumference measured. They were single-sire mated to ten to twelve, whiteface ewe lambs during a 45-day breeding season (October 15-December 1). First-service conception rates, total conception rate, lambing percentage and lambing percentage per ewe exposed were calculated for each ram and breed. The mean scrotal circumference was 36.5 cm (range 31-41.5 cm). The breeding data was then compared for eleven rams with a scrotal circumference of less than 36.5 cm and nine rams greater than 36.5 cm. No direct relationship was demonstrated between scrotal circumference, sperm motility or morphology with fertility in the rams used in this experiment. However, there was a tendency for rams with a high first-service conception rate to have sired more lambs per ewe exposed. The mean first-service conception rate was 63.2% (range 44.4-80.0%). When rams with greater than 63.2% first-service conception rate were compared to those with less than 63.2%. the lambs born per ewe exposed were 1.04 and .89, respectively, a significant difference (P<.05). There were no significant differences (P<.05) in performance between the two groups when rams with a scrotal circumference less than 36.5 cm and greater than 36.5 cm were compared, nor were there any differences between scrotal circumference, sperm motility, and morphology when rams with total conception rates greater than 80% were compared to those with conception rates less than 80%.

Journal Article↗
PubMed1992

Seasonal preovulatory overripeness ovopathy: a reappraisal of the concept.

Seasonal Preovulatory Overripeness Ovopathy (SPOO) is one explanation for seasonal variations in the occurrence of congenital anomalies. This concept entails that during some seasons the preovulatory phase of the development of the human egg is lengthened, causing congenital anomalies. Although the concept of SPOO provides an innovative explanation for the etiology of congenital anomalies, its dissemination in the scientific world has been limited. The aim of this paper is to explain this limited dissemination through a critical examination of the concept itself. To do this we analyzed the degree in which this concept has a sufficient informative content and explanatory power, following criteria formulated by Popper. It is concluded that descriptions of the concept of SPOO are ambiguous. Thus the concept cannot be tested and has a limited informative content. The explanatory power of the SPOO concept remains unclear, in itself and relative to competing explanations. Further one of its basic assumptions, seasonal variation of the length of the preovulatory phase due to an endogenous mechanism, has been refuted. Future research should better be directed to causes of preovulatory overripeness ovapathy (OO) other than seasonality. This preovulatory OO offers an innovative view on the etiology of congenital anomalies.

Congenital Abnormalities↗
PubMed1992

An analysis of the concept of homesickness.

This report analyzes the concept of homesickness, using the pattern for concept analysis presented by Chinn and Jacobs. Concept analysis is a process used to better understand a concept that has been first identified through clinical practice. This concept analysis clarifies and defines the concept of homesickness, and distinguishes homesickness from other concepts, including separation anxiety, school phobia, translocation syndrome, and relocation effects. By carefully defining what homesickness is and what it is not, criteria have emerged so that other instances of similar characteristics can be appropriately labeled. In addition, arising from the literature review and criteria are research questions and nursing interventions.

Adaptation, Psychological↗
PubMed2004

Auditing concept categorizations in the UMLS.

The Unified Medical Language System (UMLS) integrates about 880,000 concepts from 100 biomedical terminologies. Each concept is categorized to at least one semantic type of the Semantic Network. During the integration, it is unavoidable that some categorization errors and inconsistencies will be introduced. In this paper, we present an auditing technique to find such errors and inconsistencies. Our technique is based on an expert reviewing the pure intersections of meta-semantic types of a metaschema, a compact abstract view of the UMLS Semantic Network. We use a divide and conquer approach, handling differently small pure intersections and medium to large pure intersections. By using this approach, we limit the number of concepts reviewed, for which we expect a high percentage of errors. We reviewed all concepts in 657 pure intersections containing one to 10 concepts. Various kinds of errors are identified and the analysis of the results are presented in the paper. Also, we checked the pure intersections containing more than 10 concepts for their semantic soundness, where the semantically suspicious pure intersections are presented in the paper and their concepts are reviewed.

Abstracting and Indexing↗
PubMed2004

Risk factors for adverse outcomes in spontaneous versus assisted conception twin pregnancies.

OBJECTIVE: To evaluate risk factors for adverse outcomes in spontaneous vs. assisted conception twin pregnancies. DESIGN: Historical cohort study. SETTING: Four academic tertiary medical centers. PATIENT(S): Women with twin pregnancies, including 2,143 spontaneous and 424 assisted conception; 2,492 nonreduced and 75 reduced. INTERVENTION(S): None (observational). MAIN OUTCOME MEASURE(S): Preeclampsia, preterm premature rupture of membranes, birth <32 weeks and <30 weeks, low birth weight, very low birth weight, and slowed midgestation fetal growth (<10th percentile between 20 and 28 weeks). RESULT(S): Among nonreduced pregnancies, assisted conception was not significantly associated with any adverse outcomes; among nulliparas, the risk for preeclampsia was increased regardless of method of conception; among spontaneous conceptions, the risks for preterm premature rupture of membranes, low birth weight, very low birth weight, and slowed midgestation fetal growth were increased. Among all pregnancies, fetal reduction increased risks for birth <32 weeks and <30 weeks, low birth weight, very low birth weight, and slowed midgestation fetal growth. Among nulliparas with assisted conceptions, fetal reduction increased the risks for birth <30 weeks, very low birth weight, and slowed midgestation fetal growth. CONCLUSION(S): These findings indicate that in twin pregnancies, assisted conception is not a risk factor for adverse outcomes, but rather specific factors that are more common among these pregnancies, such as nulliparity and fetal reduction, increase risks.

Adult↗
PubMed2006

Kant's concept of natural purpose and the reflecting power of judgement.

This paper examines how in the 'Critique of teleological judgment' Kant characterized the concept of natural purpose in relation to and in distinction from the concepts of nature and the concept of purpose he had developed in his other critical writings. Kant maintained that neither the principles of mechanical science nor the pure concepts of the understanding through which we determine experience in general provide adequate conceptualizations of the unique capacities of organisms. He also held that although the concept of natural purpose was derived through reflection upon an analogy to human purposive activity in artistic production and moral action, it articulates a unique notion of intrinsic purposiveness. Kant restricted his critical reflections on organisms to phenomena that can be given to us in experience, criticizing speculations on their first origins or final purpose. But I argue that he held that the concept of natural purpose is a product of the reflecting power of judgment, rather than an empirical concept, and represents only the relation of things to our power of judgment. Yet it is necessary for the identification of organisms as organized and self-organizing, and as subject to unique norms and causal relations between parts and whole.

Biological Science Disciplines↗
PubMed2006

On the failure of modern species concepts.

The modern age of species concepts began in 1942, when Ernst Mayr gave concept names to several different approaches to species identification. A long list of species concepts then followed, as well as a complex literature on their merits, motivations and uses. Some of these complexities arose as a consequence of the semantic shift that Mayr introduced, in which procedures for identifying species were elevated to concepts. Much of the debate in recent decades over concepts, and over pluralism versus monism, can be seen as an unnecessary consequence of treating species identification criteria as if they were more fundamental concepts. Recently, biologists have begun to recognize both the shortcomings of a lexicon of multiple species concepts and a common evolutionary idea that underlies them.

Animals↗
PubMed2001

Incidence of premature estrus in lactating dairy cows and conception rates to standing estrus or fixed-time inseminations after synchronization using GnRH and PGF(2alpha).

Fixed-time AI (TAI) after GnRH-PGF(2alpha)-GnRH treatment is a method to achieve pregnancies in dairy herds without estrous detection. However, cows that fail to respond to the initial GnRH may have compromised TAI conception rates due to asynchronous ovarian response. This study documented the percentage of GnRH-treated Holstein cows (n=345) in two herds that displayed estrus at an inopportune time for optimum TAI conception rate (< or =48h post-PGF(2alpha); premature estrus (PE)) and compared conception rates of two TAI protocols in cows that did not display PE. At biweekly herd health exams, cows diagnosed as not pregnant to a previous AI and cows >80 days postpartum with no AI were treated with 100 microg GnRH (day -7) and 25mg PGF(2alpha) (day 0). Cows detected in PE by twice-daily visual observation from day -7 to day 2 were bred by AI 8-12h later. Cows not detected in PE were randomly assigned by parity, body condition score, and postpartum interval to receive either: (1) 100microg GnRH at 48h after PGF(2alpha) and TAI 16 to 18h later (Ovsynch); or (2) TAI at 72h post-PGF(2alpha) and a concurrent 100 microg GnRH injection to those cows not detected in estrus between 48 and 72h post-PGF(2alpha) (modified Ovsynch (MOV)). All hormone injections were im. Twenty percent (68/345) of the cows were detected in estrus before 48 after PGF(2alpha), of which 5% (17/345) were detected in estrus before PGF(2alpha) (< or =day 0). Herd influenced the percentage of cows in the PE group (herd A versus herd B; 25% versus 14%; P<0.05). Conception rates were not affected by treatment (PE versus Ovsynch versus MOV; 32% (21/65) versus 30% (37/125) versus 32% (47/145); P>0.10). However, within MOV-treated cows, conception rates were greater (P<0.05) in cows detected in estrus (46% (23/50)) compared with cows not detected in estrus (25% (24/95)). In conclusion, 20% of GnRH-treated cows displayed PE and necessitates estrous detection during this period if maximal pregnancy rates are to be achieved. Although additional estrous detection is required compared to Ovsynch, reduced cow handling and hormone usage, efficient use of expensive semen through greater conception rates in cows detected in estrus, and comparable TAI conception rates, suggests the MOV protocol may be a cost effective alternative to Ovsynch in many dairy herd reproductive management programs.

Animals↗
PubMedDate not supplied

The probability of conception on different days of the cycle with respect to ovulation: an overview.

Several mathematical models have been developed over the past thirty years to investigate how the probability of conception changes on the different days of the cycle with respect to ovulation. A problem general to all models is to estimate the day of ovulation. Since the most fertile days are those close to ovulation, less precise estimates of this event will lead to less accurate estimates of the probability of conception on a given day of the cycle. Given that a reference point for ovulation is available, the first model considered conception as dependent only on the timing of intercourse. Conception was found to be most likely to occur on only six days in each cycle. However, the model is biologically unrealistic because it assumes that all ova can be fertilized and lead to a viable pregnancy. There are other factors that affect the probability of conception, including whether the ovum is viable or not. Recent models have extended the idea of cycle viability to allow for differences between cycles within couples and for the introduction of couple specific covariates. In a second group of models the probability of conception depends mainly on the time of intercourse and the survival times of sperm and ovum. A graphical summary of the results available in the literature is presented. Conception probabilities have been found to be significantly different from zero from five days before ovulation to the day of ovulation itself. On average, less than half of the cycles are viable in women, although recent studies suggest that different cycle viability between women should be taken into account. Survival times for sperm and the ovum have been estimated to be 1.4 days and 0.7 days, respectively. Sperm would have a 5% probability of surviving more than 4.4 days and a 1% probability of surviving more than 6.8 days.

Female↗
PubMed2000

Minimization of Boolean complexity in human concept learning.

One of the unsolved problems in the field of human concept learning concerns the factors that determine the subjective difficulty of concepts: why are some concepts psychologically simple and easy to learn, while others seem difficult, complex or incoherent? This question was much studied in the 1960s but was never answered, and more recent characterizations of concepts as prototypes rather than logical rules leave it unsolved. Here I investigate this question in the domain of Boolean concepts (categories defined by logical rules). A series of experiments measured the subjective difficulty of a wide range of logical varieties of concepts (41 mathematically distinct types in six families--a far wider range than has been tested previously). The data reveal a surprisingly simple empirical 'law': the subjective difficulty of a concept is directly proportional to its Boolean complexity (the length of the shortest logically equivalent propositional formula)--that is, to its logical incompressibility.

Humans↗
PubMed2001

Concept analysis: abuse of ageing caregivers by elderly care recipients.

PURPOSE: The purpose of this article is to clarify the concept of abuse within the context of ageing women who are at risk for or experiencing physical or emotional injury inflicted by elderly family members for whom they provide care. BACKGROUND: The study of abuse of ageing individuals in family caregiving situations has traditionally focused on abuse of the dependent care receiver. However, evidence supports the health risks related to abuse of ageing caregivers as well. Women, usually spouses, daughters, or daughters-in-law, most frequently assume the caregiver role. METHODS: A modification of the strategies for concept analysis proposed by Walker and Avant (1995) is used to clarify the concept of caregiver abuse. Searches of the professional literature reveal that caregiver abuse is rarely addressed; therefore, the broader concept of elder abuse is reviewed and then placed within the general context of family caregiving. Audiotapes of the first session of a community based intervention research study entitled Intervention for the Abuse of Ageing Caregivers (Phillips et al., NIH Grant No. R01 DA-AG11155-01, 1996), in which ageing women caregivers described abusive caregiving situations, were analysed qualitatively using the principles of concept analysis. The audiotapes serve as a second source of data for the concept analysis process. FINDINGS: Antecedents, defining characteristics, and consequences of abuse of ageing caregivers were identified through the process of concept analysis. Model, contrary, and borderline cases are presented to illustrate the findings. CONCLUSIONS: Findings supported the need for awareness that ageing caregivers can be placed at risk by verbally and physically abusive behaviours of the elders for whom they provide care. Use of the term 'abuse' by health care professionals has potentially negative consequences for identification and intervention in cases of potential or actual caregiver abuse.

Adaptation, Psychological↗
PubMed2004

Psychological distress: concept analysis.

BACKGROUND: The term 'distress' is frequently used in nursing literature to describe patient discomfort related to signs and symptoms of acute or chronic illness, pre- or post-treatment anxiety or compromised status of fetuses or the respiratory system. 'Psychological distress' may more accurately describe the patient condition to which nurses respond than does the term 'distress'. Psychological distress is seldom defined as a distinct concept and is often embedded in the context of strain, stress and distress. This creates confusion for nurses attempting to manage the care of people experiencing psychological distress. AIMS: This paper is a concept analysis of psychological distress based on Walker and Avant's (1995) criteria that identifies the attributes, antecedents, and consequences of psychological distress based upon the findings of the literature review. In addition, empirical references are identified and constructed cases presented. METHODS: A literature search was conducted using MEDLINE, CINAHL, Ovid, PsychINFO, and Cancer Lit databases over the last 50 years. The purposes of this concept analysis were: (1) to establish the concept of psychological distress as a clear and distinct concept, separate from strain, stress and distress, and (2) to provide nurses with a base of knowledge from which to plan effective clinical interventions. FINDINGS: Content analysis of the literature revealed that, although used frequently in health care literature, the origin of the concept of psychological distress has not been clearly articulated and is ill-defined. CONCLUSIONS: Psychological distress is a serious problem faced by many of the people whom nurses encounter on a daily basis. An understanding of the concept of psychological distress will help nurses ameliorate this problem in patients. Nursing research related to the exploration of psychological distress is also needed.

Humans↗
PubMed2003

An exploration of the concept of comfort.

This paper explores the concept of comfort within conceptual frameworks that identify comfort as a key component. The paper focuses on two main issues: firstly, descriptions of comfort and how comfort is defined; secondly, the relationship between comfort and other core concepts and how it is similar to, or differs from these concepts. The descriptions of comfort identify the difficulty of defining comfort and note that historical interpretations of comfort have changed over time. Key authors provide different perspectives of comfort and hence a uniform definition is not evident. The degree to which patients' perspectives are represented varies within the frameworks which suggests that further clarity is needed in this area. The relationship between comfort and other concepts considers the boundaries between comfort and two concepts: nursing as therapy and caring. Comfort tends to be seen as a minor aspect of these concepts focusing on relief of discomfort or actions that demonstrate caring. The paper concludes that there is a lack of clarity around the use of the term comfort which fits with a view of comfort as an emerging concept. Descriptions of comfort are clearly evident in the literature but differ in relation to the authors' views of nursing. The relationship between comfort and nursing as therapy and caring is also complex and highlights the debate in relation to comfort as a part of caring or as the overall focus of care.

Empathy↗
PubMed2003

Species concepts and species reality: salvaging a Linnaean rank.

The validity of the species category (rank) as a distinct level of biological organization has been questioned. Phenetic, cohesion and monophyletic species concepts do not delimit species-level taxa that are qualitatively distinct from lower or higher taxa: all organisms throughout the tree of life exhibit varying degrees of similarity, cohesion, and monophyly. In contrast, interbreeding concepts delimit species-level taxa characterized by a phenomenon (regular gene flow) not found in higher taxa, making the species category a distinct level of biological organization. Only interbreeding concepts delimit species-level taxa that are all comparable according to a biologically meaningful criterion and qualitatively distinct from entities assigned to other taxonomic categories. Consistent application of interbreeding concepts can result in counterintuitive taxonomies--e.g. many wide polytypic species in plants and narrow cryptic species in animals. However, far from being problematic, such differences are biologically illuminating--reflecting differing barriers to gene flow in different clades. Empirical problems with interbreeding concepts exist, but many of these also apply to other species concepts, whereas others are not as severe as some have argued. A monistic view of species using interbreeding concepts will encounter strong historical inertia, but can save the species category from redundancy with other categories, and thus justify continued recognition of the species category.

Classification↗
PubMedDate not supplied

[Epidemiology in the study of human ecology - concept and evaluation of a seminar].

BACKGROUND: To assure proper methodology in medical studies epidemiology is the crucial profession. Medical students become acquainted with epidemiology within the course on human ecology. One year ago our department had the opportunity to assume the responsibility of this epidemiological seminar and to establish an activating teaching concept. IMPLEMENTATION: In a two hour lecture, types of epidemiologic studies, their application, typical measures, strengths and limitations are illustrated on actual examples. The basic concepts of bias, confounding and causal inference are introduced. In a two hour seminar the students read and discuss primary literature on the question "Do allergic diseases increase?" in small groups. The students present the answers on provided questions in the plenum. The results are discussed together. METHOD OF EVALUATION: At the end of each seminar within the course students rate the structural and procedural quality by means of a questionnaire. RESULTS: Compared to the former frontal teaching in epidemiology students rate the activating teaching concept significantly better in respect to lecturing style, discussion moderation, own contribution, contribution of others and course material. Comparison to the seminar "National health reporting system" (different subject, but same teaching concept and same instructor) yielded no significant differences, nor did the comparison between different instructors with the same teaching concept at the same seminar. CONCLUSIONS: The structural and procedural quality of the activating teaching concept in epidemiology is rated significantly better than the former frontal teaching concept. This difference is based on conceptual differences and not on different instructors or different subjects.

Curriculum↗
PubMed2002

[On the history of the concept neurasthenia and its modern variants chronic-fatigue-syndrome, fibromyalgia and multiple chemical sensitivities].

This article deals with the history of the terminological and nosological development of the concept neurasthenia introduced in 1869 by George Miller Beard and in particular with its reappearance in western medicine in the 1980 s. Beginning with its predecessors in antiquity and continuing with hypochondria, which became a fashionable disease in the 18 th century, the concept neurasthenia reached a high point and world-wide medical acceptance at the end of the 19 th/beginning of the 20 th century. However, between the 1930 s and 1960 s it declined in popularity and gradually disappeared until finally it only had a rudimentary nosological role in the term "pseudoneurasthenia". In the countries of the Far East, on the contrary, the concept of neurasthenia has been in continual use since its importation in the first decades of the last century. In the 1980 s, when an interest in the symptoms of chronic fatigue was reawakened in western medicine, the concept neurasthenia reappeared, this time to define the particular form of a neurotic disorder. Parallel to these developments increasing importance was attached to clinical descriptions of illnesses which on account of their similarity to the symptoms of neurasthenia could be termed modern variants of the concept neurasthenia. These are "Chronic-Fatigue-Syndrome", "Fibromyalgia" and "Multiple Chemical Sensitivities" which have more or less adopted the organic inheritance of Beard's former concept of neurasthenia, despite the fact that so far the question of organicity could not be decisively answered in a single case. In order to clarify possible influences on the development of the concept neurasthenia and its variants, the theories and ideas of E. Shorter, medical historian at the University of Toronto, are discussed in the final part of the article, whereby the particular cultural background in each case has a decisive influence on the manifestation of the psychosomatic symptoms.

Depression↗
PubMed1999

Antiarrhythmic surgery for treatment of atrial fibrillation--new concepts.

Curative treatment of atrial fibrillation is one of the main challenges of todays electrophysiology. The ideal treatment strategy should be effective, safe, and easy to apply to allow a widespread use. In addition, curative treatment should not only aim on the restoration of sinus rhythm but also restore mechanical atrial function to improve hemodynamics thereby avoiding anticoagulation. With respect to percutaneous catheter ablation no treatment concept with proven efficiency to cure chronic permanent atrial fibrillation is currently available. Surgical techniques such as the Corridor operation and the left atrial isolation procedure have been shown to effectively store sinus rhythm but these procedures do not restore biatrial transport function. Cox's Maze procedure is highly effective, however, it is an extensive and very time consuming technique which precludes the widespread application of this operation. Thus, new intraoperative treatment concepts are currently under intense clinical investigation. Most new concepts aim on the application of contiguous radiofrequency-induced lesion lines in the atria. Some of the new treatment strategies are based on the replacement of the surgical incisions of the Maze procedure using inrtraoperative radiofrequency coagulation thereby preventing functional determined reentrant circuits. Other new concepts aim on the induction of contiguous atrial lesion lines to eliminate anatomical determined atrial reentrant circuits. The main advantage of these new concepts when compared to the Maze procedure is a significantly shorter treatment time of approximately 20 minutes. In addition, some treatment strategies can also be applied in conjunction with minimally invasive cardiac surgery. The initial results reported with application of new treatment concepts indicate that approximately 60-80% of patients operated on can be cured from atrial fibrillation. Randomised studies with these new treatment strategies are necessary to validate the results and to outline which treatment concept may prove superior to others. Based on the progress made, it can be expected that intraoperative ablation of chronic permanent atrial fibrillation will become an important curative treatment strategy.

Atrial Fibrillation↗
PubMed2005

Ernst Mayr and the modern concept of species.

Ernst Mayr played a central role in the establishment of the general concept of species as metapopulation lineages, and he is the author of one of the most popular of the numerous alternative definitions of the species category. Reconciliation of incompatible species definitions and the development of a unified species concept require rejecting the interpretation of various contingent properties of metapopulation lineages, including intrinsic reproductive isolation in Mayr's definition, as necessary properties of species. On the other hand, the general concept of species as metapopulation lineages advocated by Mayr forms the foundation of this reconciliation, which follows from a corollary of that concept also advocated by Mayr: the proposition that the species is a fundamental category of biological organization. Although the general metapopulation lineage species concept and Mayr's popular species definition are commonly confused under the name "the biological species concept," they are more or less clearly distinguished in Mayr's early writings on the subject. Virtually all modern concepts and definitions of the species category, not only those that require intrinsic reproductive isolation, are to be considered biological according to the criterion proposed by Mayr. Definitions of the species category that identify a particular contingent property of metapopulation lineages (including intrinsic reproductive isolation) as a necessary property of species reduce the number of metapopulation lineages that are to be recognized taxonomically as species, but they cause conflicts among alternative species definitions and compromise the status of the species as a basic category of biological organization.

Animals↗