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Kenneth L. Campbell

Bio: Kenneth L. Campbell is an academic researcher from University of Massachusetts Boston. The author has contributed to research in topics: Population & Crash. The author has an hindex of 24, co-authored 78 publications receiving 2449 citations. Previous affiliations of Kenneth L. Campbell include Aberdeen Royal Infirmary & University of North Carolina at Chapel Hill.
Topics: Population, Crash, Poison control, Truck, Collision


Papers
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TL;DR: The extremely prolonged contraceptive effect of breastfeeding in this population appears to be due to a slow decline in suckling frequency with time since parturition and the absence of a decline over time in hypothalamic-pituitary responsiveness to the suckling stimulus.
Abstract: The effects of infant suckling patterns on the post-partum resumption of ovulation and on birth spacing are investigated among the Gainj of highland New Guinea. Based on hormonal evidence the median duration of lactational anovulation is 20.4 months accounting for about 75% of the median interval between live birth and next successful conception (i.e. resulting in live birth). Throughout lactation suckling episodes are short and frequent the interval changing slowly over time from 24 minutes in newborns to 80 minutes in 3-year olds. Maternal serum prolactin concentrations decline in parallel with the changes in suckling patterns approaching the level observed in non-nursing women by about 24 months postpartum. A path analysis indicates that the interval between suckling episodes is the principal determinant of maternal prolactin concentration with time since parturition affecting prolactin secretion only in so far as it affects suckling frequency. The extremely prolonged contraceptive effect of breastfeeding in this population thus appears to be due to 1) a slow decline in suckling frequency with time since parturition; and 2) absence of a decline over time in hypothalamic-pituitary responsiveness to the suckling stimulus. (authors modified)

80 citations

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TL;DR: Characteristics of the operating environment were found to have larger effects on the accident rate than tractor configuration (except for the bobtail), and rates varied by a factor of up to 6.8, depending on the road type.

57 citations

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TL;DR: The analysis substantiate an elevated risk of fatal accident involvement for younger drivers of large trucks and concludes that the basic trend with driver age shown in the aggregate data is primarily associated with age.

52 citations

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TL;DR: In the early 1980s, the Music Television network began airing rock music videos 24-hours a day to cable subscribers across the United States as mentioned in this paper, which usually featured band members either performing the music or acting out roles suggested by the lyrics and music.
Abstract: In August 1981 the Music Television network began airing rock music videos 24-hours a day to cable subscribers across the United States. The videos were 3-5 minute long visual depictions set to music and usually featured band members either performing the music or acting out roles suggested by the lyrics and music. By the end of 1984 one quarter of American households with televisions were viewing the MTV channel.’ I Eighty three percent of the target audience, 18-to-34year-olds, were watching an average of one hour during the day and

48 citations

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TL;DR: In this article, expandable metallic stents were placed in colorectal cancer patients for the management of stenosing lesions in patients with advanced metastatic disease or with serious medical complications which prevented immediate surgery.

46 citations


Cited by
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Journal ArticleDOI
TL;DR: Preface to the Princeton Landmarks in Biology Edition vii Preface xi Symbols used xiii 1.
Abstract: Preface to the Princeton Landmarks in Biology Edition vii Preface xi Symbols Used xiii 1. The Importance of Islands 3 2. Area and Number of Speicies 8 3. Further Explanations of the Area-Diversity Pattern 19 4. The Strategy of Colonization 68 5. Invasibility and the Variable Niche 94 6. Stepping Stones and Biotic Exchange 123 7. Evolutionary Changes Following Colonization 145 8. Prospect 181 Glossary 185 References 193 Index 201

14,171 citations

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TL;DR: In this paper, the Shand-McDougall concept of sentiment is taken over and used in the explanation of moral motivation, which is reinforced by social pressures and by religion, treating as an effort of finite man to live in harmony with the infinite reality.
Abstract: In his Preface the author' says that he started out to review all the more important theories upon the topics ordinarily discussed under human motivation but soon found himself more and more limited to the presentation of his own point of view. This very well characterizes the book. It is a very personal product. It is an outline with some defense of the author's own thinking about instincts and appetites and sentiments and how they function in human behavior. And as the author draws so heavily upon James and McDougall, especially the latter, the book may well be looked upon as a sort of sequel to their efforts. There is a thought-provoking distinction presented between instinct and appetite. An instinct is said to be aroused always by something in the external situation; and, correspondingly, an appetite is said to be aroused by sensations from within the body itself. This places, of course, a heavy emphasis upon the cognitive factor in all instinctive behaviors; and the author prefers to use the cognitive factor, especially the knowledge of that end-experience which will satisfy, as a means of differentiating one instinct from another. In this there is a recognized difference from McDougall who placed more emphasis for differentiation upon the emotional accompaniment. The list of instincts arrived at by this procedure is much like that of McDougall, although the author is forced by his criteria to present the possibility of food-seeking and sex and sleep operating both in the manner of an appetite and also as an instinct. The Shand-McDougall concept of sentiment is taken over and used in the explanation of moral motivation. There is the development within each personality of a sentiment for some moral principle. But this sentiment is not a very powerful motivating factor. It is reinforced by social pressures and by religion, which is treated as an effort of finite man to live in harmony with the infinite reality. Those whose psychological thinking is largely in terms of McDougall will doubtless find this volume a very satisfying expansion; but those who are at all inclined to support their psychological thinking by reference to experimental studies will not be so well pleased. The James-Lange theory, for example, is discussed without mention of the many experimental studies which it has provoked. Theoretical sources appear in general to be preferred to experimental investigations.

1,962 citations

Journal Article
TL;DR: This beautifully printed and well-illustrated stiff paperbacked volume is, and will for a few years yet remain, an invaluable companion to a full-scale textbook on congenital heart disease.
Abstract: argument is often, if not acrimonious, at least heated. It gives an impression of the fluidity of opinion on many fundamental ideas under discussion and of the urgency with which cardiac cyanosis in the newborn is regarded. When Dr. William Muscott says that the earliest he has operated for pulmonary stenosis is on an infant 3 days old, and Sir Russell Brock agrees that the earlier in the first month that operation is undertaken the better, and when Dr. Varco asks Dr. Senning 'so far as I know they have never yet catheterized any child intrauterine in Sweden, but they have done it through the delivery canal sometimes-would you tell us the indications of the Scandinavian group for catheterization in the immediate newborn period?', one is indeed being kept up with the times. But that was two years ago and already some of the questions then debated have since been answered. This beautifully printed and well-illustrated stiff paperbacked volume is, and will for a few years yet remain, an invaluable companion to a full-scale textbook on congenital heart disease.

1,394 citations

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TL;DR: Predictions were that that testosterone would rise at puberty to moderate levels, which supported reproductive physiology and behavior, and that testosterone levels will be associated with different behavioral profiles among men, associated with life history strategies involving emphasis on either mating or parental effort.

1,109 citations

Journal ArticleDOI
TL;DR: 5 middle-level theories--energetics theory, stress-suppression theory, psychosocial acceleration theory, paternal investment theory, and child development theory--each of which applies the basic assumptions of life history theory to the question of environmental influences on timing of puberty in girls are reviewed.
Abstract: Life history theory provides a metatheoretical framework for the study of pubertal timing from an evolutionary-developmental perspective. The current article reviews 5 middle-level theories--energetics theory stress-suppression theory psychosocial acceleration theory paternal investment theory and child development theory--each of which applies the basic assumptions of life history theory to the question of environmental influences on timing of puberty in girls. These theories converge in their conceptualization of pubertal timing as responsive to ecological conditions but diverge in their conceptualization of: a. the nature extent and direction of environmental influences and; b. the effects of pubertal timing on other reproductive variables. Comparing hypotheses derived from the 5 perspectives are evaluated. An extension of W.T. Boyce and B.J. Elliss (in press) theory of stress reactivity is proposed to account for both inhibiting and accelerating effects of psychosocial stress on timing of pubertal development. This review highlights the multiplicity of (often unrecognized) perspectives guiding research raises challenges to virtually all of these and presents an alternative framework in an effort to move research forward in this arena of multidisciplinary inquiry. (authors)

836 citations