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1

Reproductive life-span and sources of mortality for alternative male life-history strategies in  

E-print Network

in sockeye salmon, Oncorhynchus nerka Stephanie M. Carlson, Harry B. Rich, Jr., and Thomas P. Quinn Abstract-killed, stranded), and reproductive life-span of male sockeye salmon, Oncorhynchus nerka (Walbaum in Artedi, 1792 par les goélands, échouage) et la durée de la vie reproductive de saumons rouges, Oncorhynchus nerka

Carlson, Stephanie

2

Experimental Evolution Reveals Antagonistic Pleiotropy in Reproductive Timing but Not Life Span in Caenorhabditis elegans  

PubMed Central

Many mutations that dramatically extend life span in model organisms come with substantial fitness costs. Although these genetic manipulations provide valuable insight into molecular modulators of life span, it is currently unclear whether life-span extension is unavoidably linked to fitness costs. To examine this relationship, we evolved a genetically heterogeneous population of Caenorhabditis elegans for 47 generations, selecting for early fecundity. We asked whether an increase in early fecundity would necessitate a decrease in longevity or late fecundity (antagonistic pleiotropy). Caenorhabditis elegans experimentally evolved for increased early reproduction and decreased late reproduction but suffered no total fitness or life-span costs. Given that antagonistic pleiotropy among these traits has been previously demonstrated in some cases, we conclude that the genetic constraint is not absolute, that is, it is possible to uncouple longevity from early fecundity using genetic variation segregating within and among natural populations. PMID:21975091

Anderson, Jennifer L.; Reynolds, Rose M.; Morran, Levi T.; Tolman-Thompson, Julie

2011-01-01

3

Effect of temperature on laboratory growth, reproduction and life span of Octopus bimaculoides  

Microsoft Academic Search

Laboratory culture of 40 Octopus bimaculoides from April 1982 to August 1983 through the full life cycle at 18°C vs 23°C provided information on the growth, reproductive biology and life span of this California littoral octopus. At 18°C, the cephalopods grew from a hatchling size of 0.07 g to a mean of 619 g in 404 d; the largest individual

J. W. Forsythe; R. T. Hanlon

1988-01-01

4

The effect of developmental nutrition on life span and fecundity depends on the adult reproductive environment in Drosophila melanogaster  

PubMed Central

Both developmental nutrition and adult nutrition affect life-history traits; however, little is known about whether the effect of developmental nutrition depends on the adult environment experienced. We used the fruit fly to determine whether life-history traits, particularly life span and fecundity, are affected by developmental nutrition, and whether this depends on the extent to which the adult environment allows females to realize their full reproductive potential. We raised flies on three different developmental food levels containing increasing amounts of yeast and sugar: poor, control, and rich. We found that development on poor or rich larval food resulted in several life-history phenotypes indicative of suboptimal conditions, including increased developmental time, and, for poor food, decreased adult weight. However, development on poor larval food actually increased adult virgin life span. In addition, we manipulated the reproductive potential of the adult environment by adding yeast or yeast and a male. This manipulation interacted with larval food to determine adult fecundity. Specifically, under two adult conditions, flies raised on poor larval food had higher reproduction at certain ages – when singly mated this occurred early in life and when continuously mated with yeast this occurred during midlife. We show that poor larval food is not necessarily detrimental to key adult life-history traits, but does exert an adult environment-dependent effect, especially by affecting virgin life span and altering adult patterns of reproductive investment. Our findings are relevant because (1) they may explain differences between published studies on nutritional effects on life-history traits; (2) they indicate that optimal nutritional conditions are likely to be different for larvae and adults, potentially reflecting evolutionary history; and (3) they urge for the incorporation of developmental nutritional conditions into the central life-history concept of resource acquisition and allocation. PMID:25859322

May, Christina M; Doroszuk, Agnieszka; Zwaan, Bas J

2015-01-01

5

Life-Span Extension by Caloric Restriction Is Determined by Type and Level of Food Reduction and by Reproductive Mode in Brachionus manjavacas (Rotifera)  

PubMed Central

We measured life span and fecundity of three reproductive modes in a clone of the monogonont rotifer Brachionus manjavacas subjected to chronic caloric restriction (CCR) over a range of food concentrations or to intermittent fasting (IF). IF increased life span 50%–70% for all three modes, whereas CCR increased life span of asexual females derived from sexually or asexually produced eggs, but not that of sexual females. The main effect of CR on both asexual modes was to delay death at young ages, rather than to prevent death at middle ages or to greatly extend maximum life span; in contrast CR in sexual females greatly increased the life span of a few long-lived individuals. Lifetime fecundity did not decrease with CCR, suggesting a lack of resource allocation trade-off between somatic maintenance and reproduction. Multiple outcomes for a clonal lineage indicate that different responses are established through epigenetic programming, whereas differences in life-span allocations suggest that multiple genetic mechanisms mediate life-span extension. PMID:22904096

2013-01-01

6

Time scale matters: genetic analysis does not support adaptation-by-time as the mechanism for adaptive seasonal declines in kokanee reproductive life span.  

PubMed

Seasonal declines of fitness-related traits are often attributed to environmental effects or individual-level decisions about reproductive timing and effort, but genetic variation may also play a role. In populations of Pacific salmon (Oncorhynchus spp.), seasonal declines in reproductive life span have been attributed to adaptation-by-time, in which divergent selection for different traits occurs among reproductively isolated temporal components of a population. We evaluated this hypothesis in kokanee (freshwater obligate Oncorhynchus nerka) by testing for temporal genetic structure in neutral and circadian-linked loci. We detected no genetic differences in presumably neutral loci among kokanee with different arrival and maturation dates within a spawning season. Similarly, we detected no temporal genetic structure in OtsClock1b, Omy1009uw, or OmyFbxw11, candidate loci associated with circadian function. The genetic evidence from this study and others indicates a lack of support for adaptation-by-time as an important evolutionary mechanism underlying seasonal declines in reproductive life span and a need for greater consideration of other mechanisms such as time-dependent, adaptive adjustment of reproductive effort. PMID:25478160

Morbey, Yolanda E; Jensen, Evelyn L; Russello, Michael A

2014-09-01

7

Time scale matters: genetic analysis does not support adaptation-by-time as the mechanism for adaptive seasonal declines in kokanee reproductive life span  

PubMed Central

Seasonal declines of fitness-related traits are often attributed to environmental effects or individual-level decisions about reproductive timing and effort, but genetic variation may also play a role. In populations of Pacific salmon (Oncorhynchus spp.), seasonal declines in reproductive life span have been attributed to adaptation-by-time, in which divergent selection for different traits occurs among reproductively isolated temporal components of a population. We evaluated this hypothesis in kokanee (freshwater obligate Oncorhynchus nerka) by testing for temporal genetic structure in neutral and circadian-linked loci. We detected no genetic differences in presumably neutral loci among kokanee with different arrival and maturation dates within a spawning season. Similarly, we detected no temporal genetic structure in OtsClock1b, Omy1009uw, or OmyFbxw11, candidate loci associated with circadian function. The genetic evidence from this study and others indicates a lack of support for adaptation-by-time as an important evolutionary mechanism underlying seasonal declines in reproductive life span and a need for greater consideration of other mechanisms such as time-dependent, adaptive adjustment of reproductive effort. PMID:25478160

Morbey, Yolanda E; Jensen, Evelyn L; Russello, Michael A

2014-01-01

8

Insulin signaling and life span  

Microsoft Academic Search

Hyperinsulinemia and metabolic diseases are known to be associated with a reduction in life span. In the presence of insulin\\u000a resistance, insulin signaling is selectively impaired, contributing to longevity shortening. Insulin indeed activates a complex\\u000a web of intracellular downstream pathways, which are involved in mechanisms regulating longevity, primarily affecting cellular\\u000a proliferation and apoptosis. Insulin resistance promotes reactive oxygen species (ROS)

Angelo Avogaro; Saula Vigili de Kreutzenberg; Gian Paolo Fadini

2010-01-01

9

EFFECT OF Chenopodium ambrosioides L. (CHENOPODIACEAE) AQUEOUS EXTRACT ON REPRODUCTION AND LIFE SPAN OF Drosophila melanogaster (Meigen) (Diptera: Drosophilidae) EFEITO DO EXTRATO AQUOSO DE Chenopodium ambrosioides L. (CHENOPODIACEA) NA REPRODUÇÃO E TEMPO DE VIDA DE Drosophila melanogaster (Meigen) (Diptera: Drosophilidae)  

Microsoft Academic Search

Several plants used in folk medicine has bioactivity that depends on dosage. Chenopodium ambrosioides is a plant with anti-helmintic and insecticide activities. The objective of this work was to observe effects of C. ambrosioides on life span and reproduction of a model-organism, Drosophila melanogaster. Larval and adults were fed on two kinds of medium: a standard nourishing medium and standard

Vanessa Cristiane WOHLENBERG; Marcelo LOPES-DA-SILVA

10

The genetics of gender and life span  

PubMed Central

Several possible and potentially overlapping genetic mechanisms have been suggested to explain differences in life span between males and females. Two recent papers in BMC Evolutionary Biology on the effects of inbreeding provide additional insight into the genetic architecture underlying life span differences between genders in two different insects. PMID:19439039

Tower, John; Arbeitman, Michelle

2009-01-01

11

The Cost of Uncertain Life Span*  

PubMed Central

A considerable amount of uncertainty surrounds the length of human life. The standard deviation in adult life span is about 15 years in the U.S., and theory and evidence suggest it is costly. I calibrate a utility-theoretic model of preferences over length of life and show that one fewer year in standard deviation is worth about half a mean life year. Differences in the standard deviation exacerbate cross-sectional differences in life expectancy between the U.S. and other industrialized countries, between rich and poor countries, and among poor countries. Accounting for the cost of life-span variance also appears to amplify recently discovered patterns of convergence in world average human well-being. This is partly for methodological reasons and partly because unconditional variance in human length of life, primarily the component due to infant mortality, has exhibited even more convergence than life expectancy. PMID:22368324

Edwards, Ryan D.

2012-01-01

12

Families as Life Span Experts  

ERIC Educational Resources Information Center

Professionals dealing with challenging behavior frequently operate detached from the other relationships in the child's life. This narrow approach has been called the unilateral strategy based on the belief that the child's outside world can be ignored and behavior can be changed by administering specific corrective interventions. In contrast,…

Brendtro, Larry K.; Mitchell, Martin L.

2011-01-01

13

Extraordinary long life spans in fruit-feeding butterflies can provide window on evolution of life span and aging  

PubMed Central

Information on the life span of organisms in the field is essential for elucidating the evolution of life span and aging. We present mark-recapture data (>30 000 marked individuals, >4000 recaptured at least once) on forty-seven species of fruit-feeding butterflies in a tropical forest in Uganda. The data reveal adult life spans in the field for several species that are significantly longer than previously recorded in Lepidoptera (butterflies and moths). Longevity records for species of which more than 100 individuals were recaptured ranged from 67 (Bicyclus auricruda) to 293 days (Euphaedra medon). In contrast to the majority of Lepidoptera which are short-lived, these all show exceptionally long life spans, and may thus help to better identify factors that affect aging, particularly when combined with information on temporal patterns in reproduction, strategies to avoid predation, and nutritional ecology. These key traits are readily measurable in butterflies and thus studies on fruit-feeding butterflies have much potential for gaining insight into the evolution of life span and aging, especially given the tradition of field-research on butterflies. PMID:17360139

Molleman, F.; Zwaan, B. J.; Brakefield, P.M.; Carey, J. R.

2007-01-01

14

Spatial Abilities across the Adult Life Span  

ERIC Educational Resources Information Center

The study investigates age-related effects across the adult life span on spatial abilities (testing subabilities based on a distinction between spatial visualization, mental rotation, and perspective taking) and spatial self-assessments. The sample consisted of 454 participants (223 women and 231 men) from 20 to 91 years of age. Results showed…

Borella, Erika; Meneghetti, Chiara; Ronconi, Lucia; De Beni, Rossana

2014-01-01

15

Identifying sexual differentiation genes that affect Drosophila life span  

Microsoft Academic Search

BACKGROUND: Sexual differentiation often has significant effects on life span and aging phenotypes. For example, males and females of several species have different life spans, and genetic and environmental manipulations that affect life span often have different magnitude of effect in males versus females. Moreover, the presence of a differentiated germ-line has been shown to affect life span in several

Jie Shen; Daniel Ford; Gary N Landis; John Tower

2009-01-01

16

Extending Cellular Life-Span with Telomerase  

NSDL National Science Digital Library

This Science magazine site contains full text of a research article: "Extension of Life-Span by Introduction of Telomerase into Normal Human Cells," by Andrea G. Bodnar et. al. (January 16, 1998; Vol 279, No. 5349--available in Adobe Acrobat [.pdf] format only) describes the Telomerase finding and includes a commentary by Titia de Lange of Rockefeller University's Laboratory of Cell Biology and Genetics. There has been a recent finding regarding telomerase, a gene which affects the mechanisms controlling human cell replication. The site above provides general information on telomerase, current telomere research, and the use of telemorase in medical practice. Telomerase increases the life-span of a cell, and is thus central to both aging and cancer.

Bodnar, Andrea G.

17

What You Should Know about Your Reproductive Time Span  

MedlinePLUS

WHATYOUSHOULDKNOWABOUT Your Reproductive Time Span S ocial norms have changed over the past few decades as women are delaying marriage, choosing not to marry, ... be able to conceive right up until the time of menopause. The time of menopause for individual ...

18

Neoplastic Growth Through the Human Life Span  

Microsoft Academic Search

\\u000a The predominant view in the scientific literature concerning the incidence of cancers throughout the human life span is that\\u000a of an eschatological process with a linear increase in the incidence favored by aging of the organism. This is considered\\u000a The Dogma and, with rare exceptions, another more realistic view of the problem is not accepted. The idea of a cancer-aging

Alvaro Macieira-Coelho

19

78. VIEW SHOWING PLACEMENT OF LIFE SPAN SHOE ON PIER ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

78. VIEW SHOWING PLACEMENT OF LIFE SPAN SHOE ON PIER 6, LOOKING NORTH, March 5, 1935 - Sacramento River Bridge, Spanning Sacramento River at California State Highway 275, Sacramento, Sacramento County, CA

20

Partner Preferences Across the Life Span: Online Dating by Older Adults  

Microsoft Academic Search

Stereotypes of older adults as withdrawn or asexual fail to recognize that romantic relationships in later life are increasingly common. The authors analyzed 600 Internet personal ads from 4 age groups: 20–34, 40–54, 60–74, and 75+ years. Predictions from evolutionary theory held true in later life, when reproduction is no longer a concern. Across the life span, men sought physical

Sheyna Sears-Roberts Alterovitz; Gerald A. Mendelsohn

2009-01-01

21

Partner Preferences Across the Life Span: Online Dating by Older Adults  

Microsoft Academic Search

Stereotypes of older adults as withdrawn or asexual fail to recognize that romantic relationships in later life are increasingly common. The authors analyzed 600 Internet personal ads from 4 age groups: 20–34, 40–54, 60–74, and 75+ years. Predictions from evolutionary theory held true in later life, when reproduction is no longer a concern. Across the life span, men sought physical

Sheyna Sears-Roberts Alterovitz; Gerald A. Mendelsohn

2011-01-01

22

Identifying sexual differentiation genes that affect Drosophila life span  

PubMed Central

Background Sexual differentiation often has significant effects on life span and aging phenotypes. For example, males and females of several species have different life spans, and genetic and environmental manipulations that affect life span often have different magnitude of effect in males versus females. Moreover, the presence of a differentiated germ-line has been shown to affect life span in several species, including Drosophila and C. elegans. Methods Experiments were conducted to determine how alterations in sexual differentiation gene activity might affect the life span of Drosophila melanogaster. Drosophila females heterozygous for the tudor[1] mutation produce normal offspring, while their homozygous sisters produce offspring that lack a germ line. To identify additional sexual differentiation genes that might affect life span, the conditional transgenic system Geneswitch was employed, whereby feeding adult flies or developing larvae the drug RU486 causes the over-expression of selected UAS-transgenes. Results In this study germ-line ablation caused by the maternal tudor[1] mutation was examined in a long-lived genetic background, and was found to increase life span in males but not in females, consistent with previous reports. Fitting the data to a Gompertz-Makeham model indicated that the maternal tudor[1] mutation increases the life span of male progeny by decreasing age-independent mortality. The Geneswitch system was used to screen through several UAS-type and EP-type P element mutations in genes that regulate sexual differentiation, to determine if additional sex-specific effects on life span would be obtained. Conditional over-expression of transformer female isoform (traF) during development produced male adults with inhibited sexual differentiation, however this caused no significant change in life span. Over-expression of doublesex female isoform (dsxF) during development was lethal to males, and produced a limited number of female escapers, whereas over-expression of dsxF specifically in adults greatly reduced both male and female life span. Similarly, over-expression of fruitless male isoform A (fru-MA) during development was lethal to both males and females, whereas over-expression of fru-MA in adults greatly reduced both male and female life span. Conclusion Manipulation of sexual differentiation gene expression specifically in the adult, after morphological sexual differentiation is complete, was still able to affect life span. In addition, by manipulating gene expression during development, it was possible to significantly alter morphological sexual differentiation without a significant effect on adult life span. The data demonstrate that manipulation of sexual differentiation pathway genes either during development or in adults can affect adult life span. PMID:20003237

2009-01-01

23

Life span extension in Drosophila melanogaster induced by morphine  

Microsoft Academic Search

The influence of morphine on the life span of Drosophila melanogaster fruit flies has been investigated. Morphine hydrochloride (MH) at concentrations of 0.01, 0.05 and 0.25 mg\\/ml was added to\\u000a a medium starting from day 5 or 54 of imaginal life. Supplementation with MH starting from day 5 of imaginal life has resulted\\u000a in significant increases in the mean life span of males

Tatyana A. Dubiley; Yury E. Rushkevich; Natalya M. Koshel; Vladimir P. Voitenko; Alexander M. Vaiserman

2011-01-01

24

REGULAR ARTICLE Plant phenology and life span influence soil pool  

E-print Network

REGULAR ARTICLE Plant phenology and life span influence soil pool dynamics: Bromus tectorum, storage, and release. Using the replacement of C3­C4 perennial grasses by the invasive annual grass Bromus tectorum as a case study, we investigated the influence of phenology and life span on pulse responses

Adair, E. Carol

25

Migraine and reproductive life.  

PubMed

Migraine is prevalent in women during the fertile age. Indeed, both neuroendocrine events related to reproductive stages (menarche, pregnancy, and menopause) and menstrual cyclicity and the use of exogenous sex hormones, such as hormonal contraception and replacement therapy, may cause significant changes in the clinical pattern of migraine. Menstrual migraine may be more severe, long-lasting, and refractory to both acute and prophylactic treatment and, therefore, requires tailored strategies. The use of headache diaries, which makes it possible to record prospectively the characteristics of every attack, is of paramount importance for evaluating the time pattern of headache and for identifying a clear link with menstrual cycle-related features. Estrogen variations are highly implicated in modulating the threshold to challenges by altering neuronal excitability, cerebral vasoactivity, pain sensitivity, and neuroendocrine axes throughout the menstrual cycle and not only at the time of menstruation. On the other hand, estrogen withdrawal may really constitute a triggering factor for migraine in women with peculiar characteristics of vulnerability with menstruation or following the discontinuation of exogenous estrogen, as happens with hormonal contraception during the fertile age or with hormone therapy at menopause. In addition, exogenous estrogen may contribute to the occurrence of neurological symptoms, such as aura. When aura occurs, hormonal treatment should be discontinued. PMID:20816431

Nappi, Rossella E; Berga, Sarah L

2010-01-01

26

A Motivational Theory of Life-Span Development  

PubMed Central

This article had four goals. First, the authors identified a set of general challenges and questions that a life-span theory of development should address. Second, they presented a comprehensive account of their Motivational Theory of Life-Span Development. They integrated the model of optimization in primary and secondary control and the action-phase model of developmental regulation with their original life-span theory of control to present a comprehensive theory of development. Third, they reviewed the relevant empirical literature testing key propositions of the Motivational Theory of Life-Span Development. Finally, because the conceptual reach of their theory goes far beyond the current empirical base, they pointed out areas that deserve further and more focused empirical inquiry. PMID:20063963

Heckhausen, Jutta; Wrosch, Carsten; Schulz, Richard

2010-01-01

27

Circadian Rhythms, Aging, and Life Span in Mammals  

NSDL National Science Digital Library

Resetting the circadian clock leads to well being and increased life span, whereas clock disruption is associated with aging and morbidity. Increased longevity and improved health can be achieved by different feeding regimens that reset circadian rhythms and may lead to better synchrony in metabolism and physiology. This review focuses on recent findings concerning the relationships between circadian rhythms, aging attenuation, and life-span extension in mammals.

Oren Froy (The Hebrew University of Jerusalem Institute of Biochemistry, Food Science and Nutrition)

2011-08-01

28

Leaf life span of floating-leaved plants  

Microsoft Academic Search

Photosynthetic capacity of floating-leaved plants is relatively high comparable with terrestrial herbaceous plants, though floating-leaved plants have a much smaller biomass with a leaf area index seldom exceeding 2m2m-2. Their rather small biomass accumulation is related to higher turnover of leaf biomass or shorter leaf life span. Life span of floating leaves reported in the literature ranged mostly from 13

T. Tsuchiya

1991-01-01

29

Self-determination -- A life-span perspective  

E-print Network

FEBRUARY 2010 FOCUS Ofl EXCeglional Self-Determination: A Life-Span Perspective Susan B. Palmer Self-determination is a construct involving causal agency and perceived indepen- dence, usually associated with transition to adulthood and adult... abilities. However, some proponents conceptualize self-determination as a life-span approach (Abery & Stancliffe, 2003; Abery & Zajac, 1996; Sands & Wehmeyer, 1996). Viewing self-determination as a lifelong process can broaden and enhance the construct...

Palmer, Susan B.

2011-12-27

30

Family Caregivers of Older Adults: A Life Span Perspective  

ERIC Educational Resources Information Center

When faced with changes in physical health, cognition, and daily functioning, older adults most frequently rely on family members for instrumental support and more intense care activities. Using a life span perspective as our guiding framework, we identified several developmental themes across the late-life caregiving research including individual…

Roberto, Karen A.; Jarrott, Shannon E.

2008-01-01

31

Understanding Aggressive Behavior Across the Life Span  

PubMed Central

Aggressive behavior is the observable manifestation of aggression and is often associated with developmental transitions and a range of medical and psychiatric diagnoses across the lifespan. As healthcare professionals involved in the medical and psychosocial care of patients from birth through death, nurses frequently encounter—and may serve as—both victims and perpetrators of aggressive behavior in the workplace. While the nursing literature has continually reported research on prevention and treatment approaches, less emphasis has been given to understanding the etiology, including contextual precipitants of aggressive behavior. This paper provides a brief review of the biological, social, and environmental risk factors that purportedly give rise to aggressive behavior. Further, many researchers have focused specifically on aggressive behavior in adolescence and adulthood. Less attention has been given to understanding the etiology of such behavior in young children and older adults. This paper emphasizes the unique risk factors for aggressive behavior across the developmental spectrum, including childhood, adolescence, adulthood, and late life. Appreciation of the risk factors of aggressive behavior, and, in particular, how they relate to age-specific manifestations, can aid nurses in better design and implementation of prevention and treatment programs. PMID:22471771

Liu, Jianghong; Lewis, Gary; Evans, Lois

2012-01-01

32

Regulation of yeast replicative life span by thiol oxidoreductases  

PubMed Central

Thiol-based redox reactions are involved in the regulation of a variety of biological functions, such as protection against oxidative stress, signal transduction and protein folding. Some proteins involved in redox regulation have been shown to modulate life span in organisms from yeast to mammals. To assess the role of thiol oxidoreductases in aging on a genome-wide scale, we analyzed the replicative life span of yeast cells lacking known and candidate thiol oxidoreductases. The data suggest the role of several pathways in regulation of yeast aging, including thioredoxin reduction, protein folding and degradation, peroxide reduction, PIP3 signaling, and ATP synthesis. PMID:20934449

Hacioglu, Elise; Esmer, Isil; Fomenko, Dmitri E.; Gladyshev, Vadim N.; Koc, Ahmet

2011-01-01

33

Decision-making heuristics and biases across the life span  

PubMed Central

We outline a contextual and motivational model of judgment and decision-making (JDM) biases across the life span. Our model focuses on abilities and skills that correspond to deliberative, experiential, and affective decision-making processes. We review research that addresses links between JDM biases and these processes as represented by individual differences in specific abilities and skills (e.g., fluid and crystallized intelligence, executive functioning, emotion regulation, personality traits). We focus on two JDM biases—the sunk-cost fallacy (SCF) and the framing effect. We trace the developmental trajectory of each bias from preschool through middle childhood, adolescence, early adulthood, and later adulthood. We conclude that life-span developmental trajectories differ depending on the bias investigated. Existing research suggests relative stability in the framing effect across the life span and decreases in the SCF with age, including in later life. We highlight directions for future research on JDM biases across the life span, emphasizing the need for process-oriented research and research that increases our understanding of JDM biases in people’s everyday lives. PMID:22023568

Strough, JoNell; Karns, Tara E.; Schlosnagle, Leo

2013-01-01

34

Women's Spirituality across the Life Span: Implications for Counseling  

ERIC Educational Resources Information Center

Women's spirituality has unique characteristics that are often ignored within the spirituality literature. The authors review the literature on women's spirituality to reveal the major themes women have identified as relevant to their spiritual journeys across the life span. Implications for counseling and ideas for practice are included after…

Briggs, Michele Kielty; Dixon, Andrea L.

2013-01-01

35

The Life-Span Perspective and Attribution Theory.  

ERIC Educational Resources Information Center

Attribution theory and gerontology would be enriched by the application of a life-span approach to attribution, involving increased attention to the age of the stimulus person and developmental factors associated with self-attribution. In studies on achievement attributions about older people, chronological age appears to be a more salient cue for…

Banziger, George

36

Neuromodulation of Behavioral and Cognitive Development across the Life Span  

ERIC Educational Resources Information Center

Among other mechanisms, behavioral and cognitive development entail, on the one hand, contextual scaffolding and, on the other hand, neuromodulation of adaptive neurocognitive representations across the life span. Key brain networks underlying cognition, emotion, and motivation are innervated by major transmitter systems (e.g., the catecholamines…

Li, Shu-Chen

2012-01-01

37

Genetic Determinants of Human Health Span and Life Span: Progress and New Opportunities  

PubMed Central

We review three approaches to the genetic analysis of the biology and pathobiology of human aging. The first and so far the best-developed is the search for the biochemical genetic basis of varying susceptibilities to major geriatric disorders. These include a range of progeroid syndromes. Collectively, they tell us much about the genetics of health span. Given that the major risk factor for virtually all geriatric disorders is biological aging, they may also serve as markers for the study of intrinsic biological aging. The second approach seeks to identify allelic contributions to exceptionally long life spans. While linkage to a locus on Chromosome 4 has not been confirmed, association studies have revealed a number of significant polymorphisms that impact upon late-life diseases and life span. The third approach remains theoretical. It would require longitudinal studies of large numbers of middle-aged sib-pairs who are extremely discordant or concordant for their rates of decline in various physiological functions. We can conclude that there are great opportunities for research on the genetics of human aging, particularly given the huge fund of information on human biology and pathobiology, and the rapidly developing knowledge of the human genome. PMID:17677003

Martin, George M; Bergman, Aviv; Barzilai, Nir

2007-01-01

38

Does Dietary Restriction Reduce Life Span in Male Fruit-feeding Butterflies?  

PubMed Central

Male life history and resource allocation is not frequently studied in aging and life span research. Here we verify that males of long-lived fruit-feeding butterfly species have reduced longevity on restricted diets (Beck 2007 Oecologia), in contrast to the common finding of longevity extension in dietary restriction experiments in Drosophila and some other organisms. Males of some of the most long-lived species of fruit-feeding butterflies were collected from Kibale Forest, Uganda, and kept on diets of either sugar or mashed banana. Seven out of eight species had non-significantly longer life spans on mashed banana diets. Data analysis using a time-varying Cox-model with species as covariate showed that males had reduced survival on the sugar diet during the first 35 days of captive life, but the effect was absent or reversed at more advanced ages. These results challenge the generality of dietary restriction as a way to extend life span in animals. We argue that such studies on males are promising tools for better understanding life history evolution and aging because males display a wider variety of tactics for obtaining reproductive success than females. PMID:19580860

Molleman, Freerk; Ding, Jimin; Boggs, Carol L.; Carey, James R.; Arlet, Ma?gorzata E.

2009-01-01

39

Copyright 2000 by the Genetics Society of America Quantitative Trait Loci for Life Span in Drosophila melanogaster  

E-print Network

in Drosophila melanogaster: Interactions With Genetic Background and Larval Density Jeff Leips and Trudy F. C; Taub et al. 1999), and Drosophila melanogaster following the onset of reproduction (Hamilton 1966Copyright © 2000 by the Genetics Society of America Quantitative Trait Loci for Life Span

Mackay, Trudy F.C.

40

Synchronizing Loss with Life Over a Life Span: A Dynamic Perspective  

ERIC Educational Resources Information Center

Synchronizing loss with life is a dynamic journey. This article explores the myths, beliefs, and dynamics of loss and life. The purpose of the article is to help clinicians assist and support their clients with the difficulties of synchronizing loss with life as they progress on their life span journey.

Browning, Frank C.

2008-01-01

41

Fundamental frequency changes of Persian speakers across the life span.  

PubMed

This study was designed to investigate changes in fundamental frequency (F0) across the life span in Persian speakers. Four hundred children and adults were asked to produce a sustained phonation of vowel /a/ and their voice samples were studied in 10 age groups. F0 was analyzed using the software Praat (Version 5.1.17.). The results revealed that (1) the mean F0 in both sexes decreases from childhood to adulthood; (2) significant F0 differences between boys and girls begin at the age of 12 years; and (3) the range of F0 changes in the life span is greater in men (178.38 Hz) than in women (113.57 Hz). These findings provide new data for Persian-speaking children, women, and men and could be beneficial for Iranian speech and language pathologists. PMID:24461477

Soltani, Majid; Ashayeri, Hasan; Modarresi, Yahya; Salavati, Mahyar; Ghomashchi, Hamed

2014-05-01

42

Essential role for autophagy in life span extension.  

PubMed

Life and health span can be prolonged by calorie limitation or by pharmacologic agents that mimic the effects of caloric restriction. Both starvation and the genetic inactivation of nutrient signaling converge on the induction of autophagy, a cytoplasmic recycling process that counteracts the age-associated accumulation of damaged organelles and proteins as it improves the metabolic fitness of cells. Here we review experimental findings indicating that inhibition of the major nutrient and growth-related signaling pathways as well as the upregulation of anti-aging pathways mediate life span extension via the induction of autophagy. Furthermore, we discuss mounting evidence suggesting that autophagy is not only necessary but, at least in some cases, also sufficient for increasing longevity. PMID:25654554

Madeo, Frank; Zimmermann, Andreas; Maiuri, Maria Chiara; Kroemer, Guido

2015-01-01

43

Rapamycin extends life- and health span because it slows aging  

PubMed Central

Making headlines, a thought-provocative paper by Neff, Ehninger and coworkers claims that rapamycin extends life span but has limited effects on aging. How is that possibly possible? And what is aging if not an increase of the probability of death with age. I discuss that the JCI paper actually shows that rapamycin slows aging and also extends lifespan regardless of its direct anti-cancer activities. Aging is, in part, MTOR-driven: a purposeless continuation of developmental growth. Rapamycin affects the same processes in young and old animals: young animals' traits and phenotypes, which continuations become hyperfunctional, harmful and lethal later in life. PMID:23934728

Blagosklonny, Mikhail V.

2013-01-01

44

Homeless Aging Veterans in Transition: A Life-Span Perspective  

PubMed Central

The need for counseling and career/educational services for homeless veterans has captured political and economic venues for more than 25 years. Veterans are three times more likely to become homeless than the general population if veterans live in poverty or are minority veterans. This mixed methods study emphasized a life-span perspective approach for exploring factors influencing normative aging and life-quality of 39 homeless veterans in Alabama and Florida. Seven descriptive quantitative and qualitative research questions framed the investigation. Study participants completed a quantitative survey reflecting their preferences and needs with a subset of the sample (N = 12) also participating in individual qualitative interview sessions. Thirty-two service providers and stakeholders completed quantitative surveys. Empirical and qualitative data with appropriate triangulation procedures provided interpretive information relative to a life-span development perspective. Study findings provide evidence of the need for future research efforts to address strategies that focus on the health and economic challenges of veterans before they are threatened with the possibility of homelessness. Implications of the study findings provide important information associated with the premise that human development occurs throughout life with specific characteristics influencing the individual's passage. Implications for aging/homelessness research are grounded in late-life transitioning and human development intervention considerations. PMID:24286010

Thompson, Carla J.; Bridier, Nancy L.

2013-01-01

45

The Life Cycle and Life Span of Namibian Fairy Circles  

PubMed Central

In Namibia of southwestern Africa, the sparse grasslands that develop on deep sandy soils under rainfall between 50 and 100 mm per annum are punctuated by thousands of quasi-circular bare spots, usually surrounded by a ring of taller grass. The causes of these so-called “fairy circles” are unknown, although a number of hypotheses have been proposed. This paper provides a more complete description of the variation in size, density and attributes of fairy circles in a range of soil types and situations. Circles are not permanent; their vegetative and physical attributes allow them to be arranged into a life history sequence in which circles appear (birth), develop (mature) and become revegetated (die). Occasionally, they also enlarge. The appearance and disappearance of circles was confirmed from satellite images taken 4 years apart (2004, 2008). The frequency of births and deaths as a fraction of the total population of circles allowed the calculation of an approximate turnover rate, and from this, an estimate of circle lifespan. Lifespan appeared to vary with circle size, with small circles averaging about 24 years, and larger ones 43–75 years. Overall lifespan averaged about 41 yr. A second, independent estimate of lifespan was made by revisiting circles 2 to 9 years after their clear status had been confirmed. This resulted in a lifespan estimate of about 60 years. Any causal explanation of fairy circles must include their birth, development and death, their mean lifespan and the variation of their features under different conditions. PMID:22761663

Tschinkel, Walter R.

2012-01-01

46

Amino acid sources in the adult diet do not affect life span and fecundity in the fruit-feeding butterfly Bicyclus anynana  

PubMed Central

1. In tropical forests, the adults of many butterfly species feed on fruits rather than nectar from flowers and have long life spans. Rotting fruit and nectar differ from each other in many respects, including sources of amino acids and microbial life. If amino acids in the adult diet can be used for reproduction, this may have facilitated the evolution of extended life spans in this guild. 2. This issue was addressed by investigating effects of banana, yeast, and amino acids in the adult diet of the fruit-feeding butterfly Bicyclus anynana (Lepidoptera) on longevity and female reproductive output in two experiments. 3. Results showed that in the fruit-feeding butterfly B. anynana: (i) banana juice, but not sliced banana or added amino acids extend life span compared with a sugar solution of similar composition; (ii) compared with this sugar solution, other cohorts (banana juice-amino acid enriched) did not have significantly higher reproductive outputs; (iii) yeast does not represent a valuable source of nutrients; (iv) caloric restriction may cause decreased life span and rate of reproduction; and (v) increased rates of reproduction have a life span cost. PMID:19081752

Molleman, Freerk; Ding, Jimin; Wang, Jane-Ling; Brakefield, Paul M.; Carey, James R.; Zwaan, Bas J.

2008-01-01

47

Partner preferences across the life span: online dating by older adults.  

PubMed

Stereotypes of older adults as withdrawn or asexual fail to recognize that romantic relationships in later life are increasingly common. The authors analyzed 600 Internet personal ads from 4 age groups: 20-34, 40-54, 60-74, and 75+ years. Predictions from evolutionary theory held true in later life, when reproduction is no longer a concern. Across the life span, men sought physical attractiveness and offered status-related information more than women; women were more selective than men and sought status more than men. With age, men desired women increasingly younger than themselves, whereas women desired older men until ages 75 and over, when they sought men younger than themselves. PMID:19485668

Alterovitz, Sheyna Sears-Roberts; Mendelsohn, Gerald A

2009-06-01

48

Explanations of a magic trick across the life span  

PubMed Central

Studying how children and adults explain magic tricks can reveal developmental differences in cognition. We showed 167 children (aged 4–13 years) a video of a magician making a pen vanish and asked them to explain the trick. Although most tried to explain the secret, none of them correctly identified it. The younger children provided more supernatural interpretations and more often took the magician's actions at face value. Combined with a similar study of adults (N = 1008), we found that both young children and older adults were particularly overconfident in their explanations of the trick. Our methodology demonstrates the feasibility of using magic to study cognitive development across the life span.

Olson, Jay A.; Demacheva, Irina; Raz, Amir

2015-01-01

49

The pineal affects life span in hamsters with heart disease.  

PubMed

Cardiomyopathic hamsters (CMH) develop heart disease early in life which leads to congestive heart failure and death as these hamsters age. We have previously shown that living in constant light or other non-24-h light-dark (LD) cycles can increase longevity in these hamsters, and the current experiment examined potential mechanisms for this effect. Thus, CMH were orchidectomized, pinealectomized, or given melatonin treatment and then placed on either 1:23 or 1:23.6 LD cycles. Orchidectomy had no effect on longevity in either LD cycle, but in 1:23.6 it did lead to death with a greater degree of heart failure. On the other hand, pinealectomy of 1:23 CMH led to changes in life span similar to those produced by placing the hamsters in 1:23.6. Moreover, melatonin implant treatment of CMH in 1:23.6 led to changes in life span that were similar to those caused by life in 1:23, at least over the first half of the survival curves. Thus, it appears that the pineal gland and melatonin may be involved in mediating the effects of non-24-h LD cycles, whether these effects are beneficial or detrimental. In addition, the testes and testosterone appear to have no role in mediating these effects. These data suggest that inhibition, rather than stimulation, of pineal function might be beneficial for those with congestive heart failure, but further experiments are necessary to clarify when during the disease process potential treatments might be helpful. PMID:9333200

Natelson, B H; Ottenweller, J E; Tapp, W N; Heung, S; Beldowicz, D

1997-11-01

50

Low-level chemiluminescence and life span of Drosophila melanogaster.  

PubMed

Spontaneous photon emission (chemiluminescence, CL) as a monitor of free radical evolution in Drosophila melanogaster which had been maintained at 25 or 30 degrees C for 5 days after emergence was measured. When maintained at 30 degrees C the fly CL intensity was stronger than at 25 degrees C. Under the condition of the higher temperature, the fly life span was shorter (mean life span = 29 days at 30 degrees C and 63 days at 25 degrees C), and oxygen consumption (3.7 microliters/mg.h at 25 degrees C, 4.9 microliters/mg.h at 30 degrees C) and the mobility (movement distance = 25 mm/min at 25 degrees C, 700 mm/min at 30 degrees C) increased, together with augmentation of phospholipid hydroperoxide in the fly total lipids. The CL spontaneously emitted from fly homogenate was decreased by the free radical scavengers both in experiments in vivo and in vitro. The hypothesis is proposed that as the oxygen metabolism grows active, the chemiluminescent reactions that involve oxygen-dependent free radical metabolism, including membrane phospholipid hydroperoxidation, contribute to the acceleration of senescence of fly bodies. PMID:1612461

Sato, T; Miyazawa, T; Kobayashi, M; Furukawa, H; Inaba, H

1992-01-01

51

Quantifying yeast chronological life span by outgrowth of aged cells.  

PubMed

The budding yeast Saccharomyces cerevisiae has proven to be an important model organism in the field of aging research. The replicative and chronological life spans are two established paradigms used to study aging in yeast. Replicative aging is defined as the number of daughter cells a single yeast mother cell produces before senescence; chronological aging is defined by the length of time cells can survive in a non-dividing, quiescence-like state. We have developed a high-throughput method for quantitative measurement of chronological life span. This method involves aging the cells in a defined medium under agitation and at constant temperature. At each age-point, a sub-population of cells is removed from the aging culture and inoculated into rich growth medium. A high-resolution growth curve is then obtained for this sub-population of aged cells using a Bioscreen C MBR machine. An algorithm is then applied to determine the relative proportion of viable cells in each sub-population based on the growth kinetics at each age-point. This method requires substantially less time and resources compared to other chronological lifespan assays while maintaining reproducibility and precision. The high-throughput nature of this assay should allow for large-scale genetic and chemical screens to identify novel longevity modifiers for further testing in more complex organisms. PMID:19421136

Murakami, Christopher; Kaeberlein, Matt

2009-01-01

52

Competitiveness across the Life Span: The Feisty Fifties  

PubMed Central

Existing theories on life-span changes in confidence or motivation suggest that individuals’ preferences to enter competitive situations should gradually decline with age. We examined competitive preferences in a field experiment using real financial stakes in 25 to 75 year olds (N=543). The critical dependent variable was whether participants chose to perform a simple mental arithmetic task either under a piece-rate payment schedule (i.e., $.25 per solved item) or a competitive payment schedule ($.50 per solved item if the overall score is better than that of a randomly selected opponent, $0 otherwise). Results revealed that competitive preferences increased across the life span until they peaked around age 50, and dropped thereafter. We also found that throughout, men had a substantially larger preference for competing than women—extending previous findings on college-aged participants. The age/gender differences in preferences were neither accounted for by actual differences in performance nor individuals’ subjective confidence. This first systematic attempt to characterize age differences in competitive behavior suggests that a simple decline conception of competitiveness needs to be reconsidered. PMID:22059714

Mayr, Ulrich; Wozniak, Dave; Davidson, Casey; Kuhns, David; Harbaugh, William T.

2012-01-01

53

Integrating the Life Course and Life-Span: Formulating Research Questions with Dual Points of Entry.  

ERIC Educational Resources Information Center

Life-span research typically begins with personal characteristics, life-course research with social context and roles. Using both points of entry will encourage interdisciplinary work as well as the study of person-context interactions. (Contains 30 references.) (SK)

Shanahan, Michael J.; Porfelli, Erik

2002-01-01

54

Aging, life span, and energetics under adult dietary restriction in lepidoptera.  

PubMed

Stressful conditions can affect resource allocation among different life-history traits. The effect of dietary restriction (DR) on longevity and reproduction has been studied in many species, but we know little about its effects on energetics, especially in flying animals that have high energy demand. We assessed the effects of DR on metabolic rate throughout the entire adult life span in two butterfly species, Colias eurytheme and Speyeria mormonia. We cut the food intake of adult females in half and measured resting metabolic rate (RMR) and flight metabolic rate (FMR) together with body mass repeatedly throughout life. In both species, DR reduced body mass, but mass-corrected FMR was not affected, indicating that flight capacity was retained. DR lowered RMR and reduced fecundity but had no effect on life span. FMR declined with age, but the rate of senescence was not affected by DR. In contrast, aging had a strong negative effect on RMR only in control females, whereas food-restricted females had more stable RMR throughout their lives. The results suggest that flight capacity is conserved during nutritional stress but that investment in flight and survival may negatively affect other important physiological processes when resources are limited. PMID:25244380

Niitepõld, Kristjan; Perez, Alejandro; Boggs, Carol L

2014-01-01

55

The progesterone antagonist mifepristone/RU486 blocks the negative effect on life span caused by mating in female Drosophila  

PubMed Central

Mating causes decreased life span in female Drosophila. Here we report that mifepristone blocked this effect, yielding life span increases up to +68%. Drug was fed to females after mating, in the absence of males, demonstrating function in females. Mifepristone did not increase life span of virgin females or males. Mifepristone reduced progeny production but did not reduce food intake. High-throughput RNA sequencing was used to identify genes up-regulated or down-regulated upon mating, and where the change was reduced by mifepristone. Five candidate positive regulators of life span were identified, including dosage compensation regulator Unr and three X-linked genes: multi sex combs (PcG gene), Dopamine 2-like receptor and CG14215. The 37 candidate negative genes included neuropeptide CNMamide and several involved in protein mobilization and immune response. The results inform the interpretation of experiments involving mifepristone, and implicate steroid hormone signaling in regulating the trade-off between reproduction and life span. PMID:25614682

Landis, Gary N.; Salomon, Matthew P.; Keroles, Daniel; Brookes, Nicholas; Sekimura, Troy; Tower, John

2015-01-01

56

The progesterone antagonist mifepristone/RU486 blocks the negative effect on life span caused by mating in female Drosophila.  

PubMed

Mating causes decreased life span in female Drosophila. Here we report that mifepristone blocked this effect, yielding life span increases up to +68%. Drug was fed to females after mating, in the absence of males, demonstrating function in females. Mifepristone did not increase life span of virgin females or males. Mifepristone reduced progeny production but did not reduce food intake. High-throughput RNA sequencing was used to identify genes up-regulated or down-regulated upon mating, and where the change was reduced by mifepristone. Five candidate positive regulators of life span were identified, including dosage compensation regulator Unr and three X-linked genes: multi sex combs (PcG gene), Dopamine 2-like receptor and CG14215. The 37 candidate negative genes included neuropeptide CNMamide and several involved in protein mobilization and immune response. The results inform the interpretation of experiments involving mifepristone, and implicate steroid hormone signaling in regulating the trade-off between reproduction and life span. PMID:25614682

Landis, Gary N; Salomon, Matthew P; Keroles, Daniel; Brookes, Nicholas; Sekimura, Troy; Tower, John

2015-01-01

57

Theoretical Propositions of Life-Span Developmental Psychology: On the Dynamics Between Growth and Decline  

Microsoft Academic Search

Life-span developmental psychology involves the study of constancy and change in behavior throughout the life course. One aspect of life-span research has been the advancement of a more general, metatheoretical view on the nature of development. The family of theoretical perspectives associated with this metatheoretical view of life-span developmental psychology includes the recog- nition of multidirectionality in ontogenetic change, consideration

Paul B. Baltes

1987-01-01

58

Theoretical Propositions of Life-Span Developmental Psychology: On the Dynamics Between Growth and Decline  

Microsoft Academic Search

Life-span developmental psychology involves the study of constancy and change in behavior throughout the life course. One aspect of life-span research has been the advancement of a more general, metatheoretical view on the nature of development. The family of theoretical perspectives associated with this metatheoretical view of life-span developmental psychology includes the recognition of multidirectionality in ontogenetic change, consideration of

Paul B. Baltes

1987-01-01

59

Age differences in five personality domains across the life span.  

PubMed

The present study addresses the issue of age differences in 5 personality domains across the life span in a cross-sectional study. In contrast to most previous studies, the present study follows a methodologically more rigorous approach to warrant that age-related differences in personality structure and mean level can be meaningfully compared. It uses data on 50 items of the Five-Factor Personality Inventory (FFPI) available from a study in a large and representative Dutch sample (N = 2,494; age range: 16 to 91 years) conducted in 1996 for the purpose of establishing norms for the FFPI. After having established strict measurement invariance, tests were made for factor covariances to be equal across age groups, revealing structural continuity of personality. Additionally, factor variances were shown to be equal across age groups. A number of age differences in the mean level of the five personality domains emerged. Specifically, older adults were, on average, more agreeable and, especially, more conscientious than middle-aged and younger adults. Findings from our study suggest that both continuity and change may mark personality over the course of life. PMID:18473642

Allemand, Mathias; Zimprich, Daniel; Hendriks, A A Jolijn

2008-05-01

60

Mice generated by in vitro fertilization exhibit vascular dysfunction and shortened life span  

PubMed Central

Children conceived by assisted reproductive technologies (ART) display a level of vascular dysfunction similar to that seen in children of mothers with preeclamspia. The long-term consequences of ART-associated vascular disorders are unknown and difficult to investigate in healthy children. Here, we found that vasculature from mice generated by ART display endothelial dysfunction and increased stiffness, which translated into arterial hypertension in vivo. Progeny of male ART mice also exhibited vascular dysfunction, suggesting underlying epigenetic modifications. ART mice had altered methylation at the promoter of the gene encoding eNOS in the aorta, which correlated with decreased vascular eNOS expression and NO synthesis. Administration of a deacetylase inhibitor to ART mice normalized vascular gene methylation and function and resulted in progeny without vascular dysfunction. The induction of ART-associated vascular and epigenetic alterations appeared to be related to the embryo environment; these alterations were possibly facilitated by the hormonally stimulated ovulation accompanying ART. Finally, ART mice challenged with a high-fat diet had roughly a 25% shorter life span compared with control animals. This study highlights the potential of ART to induce vascular dysfunction and shorten life span and suggests that epigenetic alterations contribute to these problems. PMID:24270419

Rexhaj, Emrush; Paoloni-Giacobino, Ariane; Rimoldi, Stefano F.; Fuster, Daniel G.; Anderegg, Manuel; Somm, Emmanuel; Bouillet, Elisa; Allemann, Yves; Sartori, Claudio; Scherrer, Urs

2013-01-01

61

Close relationship between leaf life span and seedling relative growth rate in temperate hardwood species  

Microsoft Academic Search

The life span of resource-acquiring organs (leaves, shoots, fine roots) is closely associated with species successional position\\u000a and environmental resource availability. We examined to what extent leaf life span is related to inter- and intraspecific\\u000a variation in seedling relative growth rate (RGR). We examined relationships between relative growth rate in mass (RGRM) or height (RGRH) and leaf life span, together

Kenji Seiwa; Kihachiro Kikuzawa

2011-01-01

62

The effects of dietary coenzyme Q on Drosophila life span.  

PubMed

Reactive oxygen species (ROS), generated as by-products of aerobic metabolism, cause damage to proteins and cellular membranes, and are thus thought to influence senescence. Caenorhabditis elegans fed on diets lacking in ubiquinone coenzyme Q (CoQ), a coenzyme in the oxidative phosphorylation pathway, show increased longevity, possibly because of reduced ROS generation. We test the role of dietary CoQ in determining Drosophila melanogaster longevity by measuring survival and cytochrome c-oxidase activity (a proxy for aerobic metabolic performance) in flies fed wild-type yeast, CoQ-less yeast, or respiratory control (RC) yeast replete with CoQ but independently deficient in mitochondrial respiration. We find no evidence that dietary manipulation of CoQ in D. melanogaster increases life span or decreases age-dependent decline in cytochrome c oxidase activity. Instead, we find evidence that flies fed a diet of respiratory-deficient yeast (CoQ-less or RC) tend to have decreased longevity and increased rates of decline in cytochrome c-oxidase activity [corrected] PMID:14677636

Palmer, Michael R; Sackton, Timothy B

2003-12-01

63

Life history theory and human reproductive behavior  

Microsoft Academic Search

The purpose of this article is to develop a model of life history theory that incorporates environmental influences, contextual\\u000a influences, and heritable variation. I argue that physically or psychologically stressful environments delay maturation and\\u000a the onset of reproductive competence. The social context is also important, and here I concentrate on the opportunity for\\u000a upward social mobility as a contextual influence

Kevin MacDonald; California State

1997-01-01

64

Genetic Determinants of Human Health Span and Life Span: Progress and New Opportunities  

Microsoft Academic Search

We review three approaches to the genetic analysis of the biology and pathobiology of human aging. The first and so far the best-developed is the search for the biochemical genetic basis of varying susceptibilities to major geriatric disorders. These include a range of progeroid syndromes. Collectively, they tell us much about the genetics of health span. Given that the major

George M. Martin; Aviv Bergman; Nir Barzilai

2007-01-01

65

Brain and Life Span in Primates Atiya Hakeem, Gisela Rodriguez Sandoval, Marvin Jones, and John Allman  

E-print Network

environmental variation. Animals i8d that have longer life spans are likely to eft,..f>-:i animals with shorter life spans. Parts of the brain enableill animals to store information about the en vulnerable to age-related dysfunction [see Allman, in press;Allman et aL, 1993b). II. Longevity in the Wild

Allman, John M.

66

The Rate of Source Memory Decline across the Adult Life Span  

ERIC Educational Resources Information Center

Previous studies have suggested that the ability to remember contextual information related to specific episodic experiences declines with advancing age; however, the exact moment in the adult life span when this deficit begins is still controversial. Source memory for spatial information was tested in a life span sample of 1,500 adults between…

Cansino, Selene; Estrada-Manilla, Cinthya; Hernandez-Ramos, Evelia; Martinez-Galindo, Joyce Graciela; Torres-Trejo, Frine; Gomez-Fernandez, Tania; Ayala-Hernandez, Mariana; Osorio, David; Cedillo-Tinoco, Melisa; Garces-Flores, Lissete; Gomez-Melgarejo, Sandra; Beltran-Palacios, Karla; Guadalupe Garcia-Lazaro, Haydee; Garcia-Gutierrez, Fabiola; Cadena-Arenas, Yadira; Fernandez-Apan, Luisa; Bartschi, Andrea; Resendiz-Vera, Julieta; Rodriguez-Ortiz, Maria Dolores

2013-01-01

67

Global quantification of contrasting leaf life span strategies for deciduous and  

E-print Network

RESEARCH PAPER Global quantification of contrasting leaf life span strategies for deciduous Department of Forest Resources, University of Minnesota, St Paul, MN 55108, USA ABSTRACT Aim Species with deciduous and evergreen leaf habits typically differ in leaf life span (LLS). Yet quantification

Minnesota, University of

68

Sequential and Coordinative Processing Dynamics in Figural Transformations across the Life Span.  

ERIC Educational Resources Information Center

Investigated the proposition that two distinct factors involved in life span cognitive development are mental speed and coordination efficiency. Results show dissociable speed of processing and working memory functioning over the life span and age-related differential effects of coordinative demands. (ET)

Mayr, Ulrich; And Others

1996-01-01

69

Qualitative Exploration of Acculturation and Life-Span Issues of Elderly Asian Americans  

ERIC Educational Resources Information Center

Awareness of aging issues across diverse populations begins the journey toward counselors becoming culturally competent across client life spans. Understanding the life-span experiences of cultural groups is important for helping professionals. The purpose of this research was to gain insight into the qualitative experiences of Asian American…

Lee, Jee Hyang; Heo, Nanseol; Lu, Junfei; Portman, Tarrell Awe Agahe

2013-01-01

70

The Time of Our Lives: Life Span Development of Timing and Event Tracking  

ERIC Educational Resources Information Center

Life span developmental profiles were constructed for 305 participants (ages 4-95) for a battery of paced and unpaced perceptual-motor timing tasks that included synchronize-continue tapping at a wide range of target event rates. Two life span hypotheses, derived from an entrainment theory of timing and event tracking, were tested. A preferred…

McAuley, J. Devin; Jones, Mari Riess; Holub, Shayla; Johnston, Heather M.; Miller, Nathaniel S.

2006-01-01

71

Skill Learning as a Concept in Life-Span Developmental Psychology: An Action Theoretic Analysis  

Microsoft Academic Search

An action theoretic account of skill learning and skill use is offered as a useful heuristic for life-span developmental psychology. It is suggested that analyses of the tasks confronting an individual and of the structure of action, as well as of the interplay of these two, have implications for the understanding of development across the life span. In particular, these

Michael Frese; Judith Stewart

1984-01-01

72

The Yeast Forkhead HCM1 Controls Life Span Independent of Calorie Restriction.  

PubMed

Regulation of life span by members of the forkhead transcription factor family of proteins is one of the most highly investigated pathways in the field of aging. Nevertheless, despite the existence of forkhead family homologues in yeast, our knowledge of these proteins' role in yeast longevity is limited. Here, we show that yeast Hcm1p forkhead is the closest homologue of the worm PHA-4 forkhead, which regulates Caenorhabditis elegans life span. Overexpressing the yeast forkhead HCM1 or its deficiency resulted in a significant extension or reduction in yeast replicative life span, respectively. HCM1 regulates stress resistance, significantly increases the mRNA levels of several stress response genes including the catalase enzymes CTA1 and CTT1, and positively regulates life span independently of calorie restriction. Thus, HCM1 is a key regulator of life span, through a mechanism independent of calorie restriction. PMID:24835838

Maoz, Noam; Gabay, Orshay; Waldman Ben-Asher, Hiba; Cohen, Haim Y

2015-04-01

73

I. Introduction Limited life span and senescence are near-  

E-print Network

, 1988), Drosophila melanogaster (Pletcher et al., 2002), and yeast (Lin et al., 2000), whereas reproduction shortens longevity in humans (Westendorp & Kirkwood, 1998), D. melanogaster (Chapman et al., 1995). Similarly, mutations in evolutionarily conserved genes encoding components of the insulin or insulin

Mackay, Trudy F.C.

74

The Influence of Dietary Fat Source on Life Span in Calorie Restricted Mice.  

PubMed

Calorie restriction (CR) without malnutrition extends life span in several animal models. It has been proposed that a decrease in the amount of polyunsaturated fatty acids (PUFAs), and especially n-3 fatty acids, in membrane phospholipids may contribute to life span extension with CR. Phospholipid PUFAs are sensitive to dietary fatty acid composition, and thus, the purpose of this study was to determine the influence of dietary lipids on life span in CR mice. C57BL/6J mice were assigned to four groups (a 5% CR control group and three 40% CR groups) and fed diets with soybean oil (high in n-6 PUFAs), fish oil (high in n-3 PUFAs), or lard (high in saturated and monounsaturated fatty acids) as the primary lipid source. Life span was increased (p < .05) in all CR groups compared to the Control mice. Life span was also increased (p < .05) in the CR lard mice compared to animals consuming either the CR fish or soybean oil diets. These results indicate that dietary lipid composition can influence life span in mice on CR, and suggest that a diet containing a low proportion of PUFAs and high proportion of monounsaturated and saturated fats may maximize life span in animals maintained on CR. PMID:25313149

López-Domínguez, José A; Ramsey, Jon J; Tran, Dianna; Imai, Denise M; Koehne, Amanda; Laing, Steven T; Griffey, Stephen M; Kim, Kyoungmi; Taylor, Sandra L; Hagopian, Kevork; Villalba, José M; López-Lluch, Guillermo; Navas, Plácido; McDonald, Roger B

2014-10-13

75

Life-span changes to adults' language: Effects of memory and genre  

E-print Network

Applied Psycholinguistics (1989) 10, 49-66 Printed in the United States of America Life-span changes to adults' language: Effects of memory and genre SUSAN K E M P E R , D O N N A KYNETTE, S H A N N O N RASH, and KEVIN O'BRIEN University... to written language across the life-span. Discourse Processes. Kemper, S., & Rash, S. J. (1988). Speech and writing across the life-span. In M. M. Gruneberg, P. E. Morris, & R. N. Sykes (Eds.), Practical aspects of memory: Current research and issues...

Kemper, Susan; Kynette, Donna; Rash, Shannon; O'Brien, Kevin

1989-01-01

76

Sex Role Orientation Across the Adult Life Span.  

ERIC Educational Resources Information Center

It was hypothesized that four different "life lines" would affect sex role orientations, specifically intimacy, parenting, grandparenting, and work. Subjects were 74 men and 43 women, white, upper middle class with a mean education level of 14 years. Each participant completed a demographic questionnaire, the Bem Sex Role Inventory, a Life Events…

Zaks, Peggy M.; And Others

77

Self-Determination across the Life Span: Issues and Gaps  

ERIC Educational Resources Information Center

This article synthesizes the literature on self-determination across the lifespan with a focus on identifying gaps that exist between theory, research, and evidence-based practices. Using a life-stages approach, it first examines issues across life phases, and then examines cross-cutting topics (employment, abuse and neglect, and health) that are…

Heller, Tamar; Schindler, Abigail; Palmer, Susan B.; Wehmeyer, Michael L.; Parent, Wendy; Jenson, Ronda; Abery, Brian H.; Geringer, Wendy; Bacon, Ansley; O'Hara, David M.

2011-01-01

78

Extension of Life-Span by Loss of CHICO, a Drosophila Insulin Receptor Substrate Protein  

Microsoft Academic Search

The Drosophila melanogaster gene chico encodes an insulin receptor substrate that functions in an insulin\\/insulin-like growth factor (IGF) signaling pathway. In the nematode Caenorhabditis elegans, insulin\\/IGF signaling regulates adult longevity. We found that mutation of chico extends fruit fly median life-span by up to 48% in homozygotes and 36% in heterozygotes. Extension of life-span was not a result of impaired

David J. Clancy; David Gems; Lawrence G. Harshman; Sean Oldham; Hugo Stocker; Ernst Hafen; Sally J. Leevers; Linda Partridge

2001-01-01

79

Herbal Supplement Extends Life Span Under Some Environmental Conditions and Boosts Stress Resistance  

PubMed Central

Genetic studies indicate that aging is modulated by a great number of genetic pathways. We have used Drosophila longevity and stress assays to test a multipath intervention strategy. To carry out this strategy, we supplemented the flies with herbal extracts (SC100) that are predicted to modulate the expression of many genes involved in aging and stress resistance, such as mTOR, NOS, NF-KappaB, and VEGF. When flies were housed in large cages with SC100 added, daily mortality rates of both male and female flies were greatly diminished in mid to late life. Surprisingly, SC100 also stabilized midlife mortality rate increases so as to extend the maximum life span substantially beyond the limits previously reported for D. melanogaster. Under these conditions, SC100 also promoted robust resistance to partial starvation stress and to heat stress. Fertility was the same initially in both treated and control flies, but it became significantly higher in treated flies at older ages as the fertility of control flies declined. Mean and maximum life spans of flies in vials at the same test site were also extended by SC100, but the life spans were short in absolute terms. In contrast, at an independent test site where stress was minimized, the flies exhibited much longer mean life spans, but the survival curves became highly rectangular and the effects of SC100 on both mean and maximum life spans declined greatly or were abolished. The data indicate that SC100 is a novel herbal mix with striking effects on enhancing Drosophila stress resistance and life span in some environments, while minimizing mid to late life mortality rates. They also show that the environment and other factors can have transformative effects on both the length and distribution of survivorship, and on the ability of SC100 to extend the life span. PMID:25879540

Villeponteau, Bryant; Matsagas, Kennedy; Nobles, Amber C.; Rizza, Cristina; Horwitz, Marc; Benford, Gregory; Mockett, Robin J.

2015-01-01

80

Inflammatory Exposure and Historical Changes in Human Life-Spans  

Microsoft Academic Search

Most explanations of the increase in life expectancy at older ages over history emphasize the importance of medical and public health factors of a particular historical period. We propose that the reduction in lifetime exposure to infectious diseases and other sources of inflam- mation—a cohort mechanism— has also made an important contribution to the historical decline in old-age mortality. Analysis

Caleb E. Finch; Eileen M. Crimmins

2004-01-01

81

Conceptions of Gay Male Life-Span Development  

Microsoft Academic Search

Four of Erikson's eight psychosocial crises were used in this qualitative, exploratory study as an organizing framework. Using a semi-structured questionnaire, seven men were interviewed with the goal of understanding how they have navigated Erikson's life stages. Significant results included: an early sense of being different and a period of time between “coming out to self” and “coming out to

David Roseborough

2004-01-01

82

Quantitative and Molecular Genetic Analyses of Mutations Increasing Drosophila Life Span  

Microsoft Academic Search

Understanding the genetic and environmental factors that affect variation in life span and senescence is of major interest for human health and evolutionary biology. Multiple mechanisms affect longevity, many of which are conserved across species, but the genetic networks underlying each mechanism and cross-talk between networks are unknown. We report the results of a screen for mutations affecting Drosophila life

Michael M. Magwire; Akihiko Yamamoto; Mary Anna Carbone; Natalia V. Roshina; Alexander V. Symonenko; Elena G. Pasyukova; Tatiana V. Morozova; Trudy F. C. Mackay

2010-01-01

83

Requirement of NAD and SIR2 for Life-Span Extension by  

E-print Network

this pathway by mutat- ing its components would mimic the life- span extension effect of low glucose con suggests that low glucose concentration and low PKA activ- ity function in the same pathway to extend life (which encodes the silencing protein Sir2p) or NPT1 (a gene in a pathway in the synthesis of NAD

Guarente, Leonard P.

84

'Willpower' over the life span: decomposing self-regulation.  

PubMed

In the 1960s, Mischel and colleagues developed a simple 'marshmallow test' to measure preschoolers' ability to delay gratification. In numerous follow-up studies over 40?years, this 'test' proved to have surprisingly significant predictive validity for consequential social, cognitive and mental health outcomes over the life course. In this article, we review key findings from the longitudinal work and from earlier delay-of-gratification experiments examining the cognitive appraisal and attention control strategies that underlie this ability. Further, we outline a set of hypotheses that emerge from the intersection of these findings with research on 'cognitive control' mechanisms and their neural bases. We discuss implications of these hypotheses for decomposing the phenomena of 'willpower' and the lifelong individual differences in self-regulatory ability that were identified in the earlier research and that are currently being pursued. PMID:20855294

Mischel, Walter; Ayduk, Ozlem; Berman, Marc G; Casey, B J; Gotlib, Ian H; Jonides, John; Kross, Ethan; Teslovich, Theresa; Wilson, Nicole L; Zayas, Vivian; Shoda, Yuichi

2011-04-01

85

Enhanced Energy Metabolism Contributes to the Extended Life Span of Calorie-restricted Caenorhabditis elegans*  

PubMed Central

Caloric restriction (CR) markedly extends life span and improves the health of a broad number of species. Energy metabolism fundamentally contributes to the beneficial effects of CR, but the underlying mechanisms that are responsible for this effect remain enigmatic. A multidisciplinary approach that involves quantitative proteomics, immunochemistry, metabolic quantification, and life span analysis was used to determine how CR, which occurs in the Caenorhabditis elegans eat-2 mutants, modifies energy metabolism of the worm, and whether the observed modifications contribute to the CR-mediated physiological responses. A switch to fatty acid metabolism as an energy source and an enhanced rate of energy metabolism by eat-2 mutant nematodes were detected. Life span analyses validated the important role of these previously unknown alterations of energy metabolism in the CR-mediated longevity of nematodes. As observed in mice, the overexpression of the gene for the nematode analog of the cytosolic form of phosphoenolpyruvate carboxykinase caused a marked extension of the life span in C. elegans, presumably by enhancing energy metabolism via an altered rate of cataplerosis of tricarboxylic acid cycle anions. We conclude that an increase, not a decrease in fuel consumption, via an accelerated oxidation of fuels in the TCA cycle is involved in life span regulation; this mechanism may be conserved across phylogeny. PMID:22810224

Yuan, Yiyuan; Kadiyala, Chandra S.; Ching, Tsui-Ting; Hakimi, Parvin; Saha, Sudipto; Xu, Hua; Yuan, Chao; Mullangi, Vennela; Wang, Liwen; Fivenson, Elayne; Hanson, Richard W.; Ewing, Rob; Hsu, Ao-Lin; Miyagi, Masaru; Feng, Zhaoyang

2012-01-01

86

Aspirin Delimits Platelet Life Span by Proteasomal Inhibition  

PubMed Central

Aspirin is widely used in clinical settings as an anti-inflammatory and anti-platelet drug due its inhibitory effect on cyclooxygenase activity. Although the drug has long been considered to be an effective and safe therapeutic regime against inflammatory and cardiovascular disorders, consequences of its cyclooxygenase-independent attributes on platelets, the key players in thrombogenesis, beg serious investigation. In this report we explored the effect of aspirin on platelet lifespan in murine model and its possible cytotoxicity against human platelets in vitro. Aspirin administration in mice led to significant reduction in half-life of circulating platelets, indicative of enhanced rate of platelet clearance. Aspirin-treated human platelets were found to be phagocytosed more efficiently by macrophages, associated with attenuation in platelet proteasomal activity and upregulation of conformationally active Bax, which were consistent with enhanced platelet apoptosis. Although the dosage of aspirin administered in mice was higher than the therapeutic regimen against cardiovascular events, it is comparable with the recommended anti-inflammatory prescription. Thus, above observations provide cautionary framework to critically re-evaluate prophylactic and therapeutic dosage regime of aspirin in systemic inflammatory as well as cardiovascular ailments. PMID:25126950

Nayak, Manasa K.; Dash, Ayusman; Singh, Nitesh; Dash, Debabrata

2014-01-01

87

Adherence to antihypertensive medications across the life span.  

PubMed

Although treatment for hypertension is readily available, poor control of hypertension is a major health problem frequently manifested in late life. Researchers believe that one of the major causes of uncontrolled hypertension is failure to take medication as directed. In this preliminary study, the medication-taking behaviors of 48 adults diagnosed with hypertension, ranging in age from 35 to 87, were recorded for 2 months with credit card-sized bar-code scanners. The social-cognitive model (Park, 1992) for understanding medication adherence, which proposes that medication adherence is governed by both beliefs and cognitive factors, was used as a basis for this research. Therefore, measures of health behaviors, attitudes about health and medication taking, and cognitive function were recorded, as well as blood pressure readings. The main findings were that (a) the oldest-old and groups of middle-aged adults were the most nonadherent, whereas the young-old were more likely to adhere than the other age groups; (b) high blood pressure readings predicted adherence to antihypertensive medications; and (c) medication beliefs influenced adherence in some situations. PMID:9343911

Morrell, R W; Park, D C; Kidder, D P; Martin, M

1997-10-01

88

Foraging across the life span: is there a reduction in exploration with aging?  

PubMed Central

Does foraging change across the life span, and in particular, with aging? We report data from two foraging tasks used to investigate age differences in search in external environments as well as internal search in memory. Overall, the evidence suggests that foraging behavior may undergo significant changes across the life span across internal and external search. In particular, we find evidence of a trend toward reduced exploration with increased age. We discuss these findings in light of theories that postulate a link between aging and reductions in novelty seeking and exploratory behavior. PMID:23616741

Mata, Rui; Wilke, Andreas; Czienskowski, Uwe

2013-01-01

89

Regulation of life span by mitochondrial respiration: the HIF-1 and ROS connection  

PubMed Central

A mild reduction in mitochondrial respiration extends the life span of many species, including C. elegans. We recently showed that hypoxia-inducible factor 1 (HIF-1) is required for the acquisition of a long life span by mutants with reduced respiration in C. elegans. We suggested that increased levels of reactive oxygen species (ROS) produced in the respiration mutants increase HIF-1 activity and lead to this longevity. In this research perspective, we discuss our findings and recent advances regarding the roles of ROS and HIF-1 in aging, focusing on the longevity caused by reduced respiration. PMID:21389351

Hwang, Ara B.; Lee, Seung-Jae

2011-01-01

90

Control of the replicative life span of human fibroblasts by p16 and the polycomb protein Bmi1  

Microsoft Academic Search

senescence, but not quiescence, and extends replicative life span when overexpressed. Life span extension by Bmi-1 required the pRb, but not p53, tumor suppressor protein. Deletion analysis showed that the RING finger and helix-turn-helix domains of Bmi-1 were required for life span extension and suppression of p16. Further- more, a RING finger deletion mutant exhibited dominant negative activity, inducing p16

Koji Itahana; Ying Zou; Yoko Itahana; Jose-Luis Martinez; Christian Beausejour; Jacqueline J. L. Jacobs; Maarten van Lohuizen; Vimla Band; Judith Campisi; Goberdhan P. Dimri

2003-01-01

91

Relationship between heat shock protein 70 expression and life span in Daphnia  

PubMed Central

The longevity of an organism is directly related to its ability to effectively cope with cellular stress. Heat shock response (HSR) protects the cells against accumulation of damaged proteins after exposure to elevated temperatures and also in ageing cells. To understand the role of Hsp70 in regulating life span of Daphnia, we examined the expression of Hsp70 in two ecotypes that exhibit strikingly different life spans. D. pulicaria, the long lived ecotype, showed a robust Hsp70 induction as compared to the shorter lived D. pulex. Interestingly, the short-lived D. pulex isolates showed no induction of Hsp70 at the mid point in their life span. In contrast to this, the long-lived D. pulicaria continued to induce Hsp70 expression at an equivalent age. We further show that the Hsp70 expression was induced at transcriptional level in response to heat shock. The transcription factor responsible for Hsp70 induction, heat shock factor-1 (HSF-1), although present in aged organisms did not exhibit DNA-binding capability. Thus, the decline of Hsp70 induction in old organisms could be attributed to a decline in HSF-1’s DNA-binding activity. These results for the first time, present a molecular analysis of the relationship between HSR and life span in Daphnia. PMID:24814302

Schumpert, Charles; Handy, Indhira; Dudycha, Jeffry L.; Patel, Rekha C.

2014-01-01

92

Life-Span Issues in the Fair and Non-Discriminatory Evaluation of Workers.  

ERIC Educational Resources Information Center

Until recently, older workers have not been recognized as a group requiring special attention in the area of fair employment practices. Thus, progress has been slow towards the development of valid and reliable indices of performance which are applicable across the life span. Research shows that many measures of employee evaluation provide no…

Alexander, Ralph A.; Barrett, Gerald V.

93

Service Learning in Life-Span Developmental Psychology: Higher Exam Scores and Increased Empathy  

ERIC Educational Resources Information Center

This article describes research conducted to evaluate the impact of service learning on exam scores and emotional empathy in a life-span development course. Service learning was 1 of 3 project options offered in the course; others included an interview project and a research paper. With the exception of the first exam, scores were significantly…

Lundy, Brenda L.

2007-01-01

94

D-Glucosamine supplementation extends life span of nematodes and of ageing mice  

PubMed Central

D-Glucosamine (GlcN) is a freely available and commonly used dietary supplement potentially promoting cartilage health in humans, which also acts as an inhibitor of glycolysis. Here we show that GlcN, independent of the hexosamine pathway, extends Caenorhabditis elegans life span by impairing glucose metabolism that activates AMP-activated protein kinase (AMPK/AAK-2) and increases mitochondrial biogenesis. Consistent with the concept of mitohormesis, GlcN promotes increased formation of mitochondrial reactive oxygen species (ROS) culminating in increased expression of the nematodal amino acid-transporter 1 (aat-1) gene. Ameliorating mitochondrial ROS formation or impairment of aat-1-expression abolishes GlcN-mediated life span extension in an NRF2/SKN-1-dependent fashion. Unlike other calorie restriction mimetics, such as 2-deoxyglucose, GlcN extends life span of ageing C57BL/6 mice, which show an induction of mitochondrial biogenesis, lowered blood glucose levels, enhanced expression of several murine amino-acid transporters, as well as increased amino-acid catabolism. Taken together, we provide evidence that GlcN extends life span in evolutionary distinct species by mimicking a low-carbohydrate diet. PMID:24714520

Weimer, Sandra; Priebs, Josephine; Kuhlow, Doreen; Groth, Marco; Priebe, Steffen; Mansfeld, Johannes; Merry, Troy L.; Dubuis, Sébastien; Laube, Beate; Pfeiffer, Andreas F.; Schulz, Tim J.; Guthke, Reinhard; Platzer, Matthias; Zamboni, Nicola; Zarse, Kim; Ristow, Michael

2014-01-01

95

Murray Rosenthal's life in Oak Ridge has spanned more than half a century.  

E-print Network

Murray Rosenthal's life in Oak Ridge has spanned more than half a century. He was around when young scientists of the time were excited about the early nuclear technology work performed at Oak Ridge. It was a great time to be here." Murray arrived in Oak Ridge with a doctorate from MIT in 1953, the same year

96

Gains and Losses in Creative Personality as Perceived by Adults across the Life Span  

ERIC Educational Resources Information Center

In this study, we used a life span model to study the subjective perception of creative personality (CP) in emerging, young, middle-aged, and older Hong Kong Chinese adults. We also asked participants to estimate the approximate age by which people develop and lose CP across adulthood. We expected an interesting interplay between internalized age…

Hui, Anna N. N.; Yeung, Dannii Y.; Sue-Chan, Christina; Chan, Kara; Hui, Desmond C. K.; Cheng, Sheung-Tak

2014-01-01

97

Toward a Life Span Theory of Close Relationships: The Affective Relationships Model  

Microsoft Academic Search

This article addresses how close relationships can be conceptualized so that they can be accurately understood over the life span. First, two typical clusters of theories of close relationships, the attachment theory and the social network theory, are compared and discussed with regard to their fundamental but controversial assumptions regarding the scope of lifelong development. Second, previous research into close

Keiko Takahashi

2005-01-01

98

COMPARISONS OF STRUCTURE AND LIFE SPAN IN ROOTS AND LEAVES AMONG TEMPERATE TREES  

Microsoft Academic Search

Global data sets provide strong evidence of convergence for leaf structure with leaf longevity such that species having thick leaves, low specific leaf area, low mass-based nitrogen concentrations, and low photosynthetic rates typically exhibit long leaf life span. Leaf longevity and corresponding leaf structure have also been widely linked to plant potential growth rate, plant competition, and nutrient cycling. We

Jennifer M. Withington; Peter B. Reich; Jacek Oleksyn; David M. Eissenstat

2006-01-01

99

Perceptions of Personal Agency and Infant Attachment: Toward a Life-Span Perspective on Competence Development  

Microsoft Academic Search

Because perceptions of personal agency are important contributors to behavioral regulation, they play a significant role in promoting and maintaining competent functioning. Yet, thus far, these processes have been studied almost exlusively in older children and adults. Our discussion sketches the outlines of a life-span approach to the study of competence development by considering the emergence of personal agency beliefs

Martin E. Ford; Ross A. Thompson

1985-01-01

100

The Status of Number and Quantity Conservation Concepts Across the Life-span.  

ERIC Educational Resources Information Center

Conservation performance during childhood to portions of the life span beyond adolescence is examined, with existing data replicated on subjects ranging from the preschool to middle-childhood years. Age differences in performance are studied for the typical Piagetian paired-stimulus equivalence conservation of number, substance, weight, and volume…

Papalia, Diane E.

101

Target of Rapamycin Signaling Regulates Metabolism, Growth, and Life Span in Arabidopsis[W][OA  

PubMed Central

Target of Rapamycin (TOR) is a major nutrition and energy sensor that regulates growth and life span in yeast and animals. In plants, growth and life span are intertwined not only with nutrient acquisition from the soil and nutrition generation via photosynthesis but also with their unique modes of development and differentiation. How TOR functions in these processes has not yet been determined. To gain further insights, rapamycin-sensitive transgenic Arabidopsis thaliana lines (BP12) expressing yeast FK506 Binding Protein12 were developed. Inhibition of TOR in BP12 plants by rapamycin resulted in slower overall root, leaf, and shoot growth and development leading to poor nutrient uptake and light energy utilization. Experimental limitation of nutrient availability and light energy supply in wild-type Arabidopsis produced phenotypes observed with TOR knockdown plants, indicating a link between TOR signaling and nutrition/light energy status. Genetic and physiological studies together with RNA sequencing and metabolite analysis of TOR-suppressed lines revealed that TOR regulates development and life span in Arabidopsis by restructuring cell growth, carbon and nitrogen metabolism, gene expression, and rRNA and protein synthesis. Gain- and loss-of-function Ribosomal Protein S6 (RPS6) mutants additionally show that TOR function involves RPS6-mediated nutrition and light-dependent growth and life span in Arabidopsis. PMID:23275579

Ren, Maozhi; Venglat, Prakash; Qiu, Shuqing; Feng, Li; Cao, Yongguo; Wang, Edwin; Xiang, Daoquan; Wang, Jinghe; Alexander, Danny; Chalivendra, Subbaiah; Logan, David; Mattoo, Autar; Selvaraj, Gopalan; Datla, Raju

2012-01-01

102

Age, growth and size interact with stress to determine life span and mortality.  

PubMed

Individuals in a large experimental field population, of the short-lived perennial species Plantago lanceolata, were followed to determine the sources of variation that influence mortality and life span. The design included multiple age groups with initially similar genetic structure, which made it possible to separate age effects from period effects and to identify the genetic component to variation in life span. During a period of stress, individuals of all ages showed parallel increases in mortality but different cohorts experienced this period of high mortality at different ages. This then influenced the distribution of life spans across cohorts. Age and size-age interactions influenced mortality during the period of stress. Smaller individuals died but only if they were old. Additionally, growth and age interacted with stress such that older individuals had negative growth and high mortality whereas younger individuals had positive growth and relatively lower mortality during stress. The results of this study show that it is not simply the environment that can have a major impact on demography in natural populations; rather, age, size and growth can interact with the environment to influence mortality and life span when the environment is stressful. PMID:22664575

Roach, Deborah Ann

2012-10-01

103

Cancer risk among atomic bomb survivors. The RERF Life Span Study. Radiation Effects Research Foundation  

Microsoft Academic Search

This article summarizes the risk of cancer among the survivors of the atomic bombing of Hiroshima and Nagasaki. We focus primarily on the risk of death from cancer among individuals in the Life Span Study sample of the Radiation Effects Research Foundation from 1950 through 1985 based on recently revised dosimetry procedures. We report the risk of cancer other than

Y. Shimizu; W. J. Schull; H. Kato

1990-01-01

104

Extending the Human Life Span: An Exploratory Study of Pro- and Anti-Longevity Attitudes  

ERIC Educational Resources Information Center

Successful efforts by biologists to substantially increase the life span of non-human animals has raised the possibility of extrapolation to humans, which in turn has given rise to bioethical argumentation, pro and con. The present study converts these arguments into pro- and anti-longevity items on a questionnaire and examines the structure and…

Kogan, Nathan; Tucker, Jennifer; Porter, Matthew

2011-01-01

105

Attachment and the Processing of Social Information across the Life Span: Theory and Evidence  

ERIC Educational Resources Information Center

Researchers have used J. Bowlby's (1969/1982, 1973, 1980, 1988) attachment theory frequently as a basis for examining whether experiences in close personal relationships relate to the processing of social information across childhood, adolescence, and adulthood. We present an integrative life-span-encompassing theoretical model to explain the…

Dykas, Matthew J.; Cassidy, Jude

2011-01-01

106

The Use of Digital Technologies across the Adult Life Span in Distance Education  

ERIC Educational Resources Information Center

In June 2010, a survey was carried out to explore access to digital technology, attitudes to digital technology and approaches to studying across the adult life span in students taking courses with the UK Open University. In total, 7000 people were surveyed, of whom more than 4000 responded. Nearly all these students had access to a computer and…

Jelfs, Anne; Richardson, John T. E.

2013-01-01

107

Developmental Change in Proactive Interference across the Life Span: Evidence from Two Working Memory Tasks  

ERIC Educational Resources Information Center

Working memory (WM) as the ability to temporarily maintain and manipulate various kinds of information is known to be affected by proactive interference (PI) from previously relevant contents, but studies on developmental changes in the susceptibility to PI are scarce. In the present study, we investigated life span development of item-specific…

Loosli, Sandra V.; Rahm, Benjamin; Unterrainer, Josef M.; Weiller, Cornelius; Kaller, Christoph P.

2014-01-01

108

Psychopathology in Williams Syndrome: The Effect of Individual Differences across the Life Span  

ERIC Educational Resources Information Center

This research aimed to comprehensively explore psychopathology in Williams syndrome (WS) across the life span and evaluate the relationship between psychopathology and age category (child or adult), gender, and cognitive ability. The parents of 50 participants with WS, ages 6-50 years, were interviewed using the Schedule for Affective Disorders…

Dodd, Helen F.; Porter, Melanie A.

2009-01-01

109

The Development of Attentional Networks: Cross-Sectional Findings from a Life Span Sample  

ERIC Educational Resources Information Center

Using a population-based sample of 263 individuals ranging from 6 to 89 years of age, we investigated the gains and losses in the abilities to (a) use exogenous cues to shift attention covertly and (b) ignore conflicting information across the life span. The participants' ability to shift visual attention was tested by a typical Posner-type…

Waszak, Florian; Li, Shu-Chen; Hommel, Bernhard

2010-01-01

110

Reproductive Life History Traits of Female Orangutans (Pongo spp.)  

Microsoft Academic Search

Data from wild populations demonstrate that orangutans have the slowest life history of all the great apes. In this chapter, we provide an overview of reproduction and life history traits of female orangutans in the wild and captivity. This comparison of wild and captive data illustrates the variability that exists for orangutans. Wild orangutan females first reproduce at a mean

R. Shumaker; S. Wich; L. Perkins

2008-01-01

111

D-chiro-inositol and pinitol extend the life span of Drosophila melanogaster.  

PubMed

D-chiro-inositol, a member of the inositol family, and pinitol, a 3-methoxy analogue of D-chiro-inositol, have been proposed to have antidiabetic, antiinflammatory, anticancer and stamina enhancing effects. We found that supplementing the diet of Drosophila with D-chiro-inositol and pinitol extended adult longevity in both male and female flies. Life span extension was accompanied by protection against oxidative and starvation stresses, improvement in health span, and no reduction in fecundity. Pinitol increased the fly life span, both in dietary restriction and in ad libitum conditions, suggesting that pinitol increased life span in a manner that was independent of the dietary restriction pathway. Nuclear localization of dFOXO increased in D-chiro-inositol and pinitol-fed flies when compared with controls. Pinitol treatment significantly activated JNK and S6K, but not AKT, indicating that the activation of dFOXO by pinitol is acquired by the activation of S6K and JNK signaling. Hence, our study indicated that D-chiro-inositol and pinitol could be novel food-derived antiaging compounds. PMID:22843669

Hada, Binika; Yoo, Mi-Ra; Seong, Ki Moon; Jin, Young-Woo; Myeong, Hyeon-Koon; Min, Kyung-Jin

2013-03-01

112

20S proteasome activation promotes life span extension and resistance to proteotoxicity in Caenorhabditis elegans.  

PubMed

Protein homeostasis (proteostasis) is one of the nodal points that need to be preserved to retain physiologic cellular/organismal balance. The ubiquitin-proteasome system (UPS) is responsible for the removal of both normal and damaged proteins, with the proteasome being the downstream effector. The proteasome is the major cellular protease with progressive impairment of function during aging and senescence. Despite the documented age-retarding properties of proteasome activation in various cellular models, simultaneous enhancement of the 20S core proteasome content, assembly, and function have never been reported in any multicellular organism. Consequently, the possible effects of the core proteasome modulation on organismal life span are elusive. In this study, we have achieved activation of the 20S proteasome at organismal level. We demonstrate enhancement of proteasome levels, assembly, and activity in the nematode Caenorhabditis elegans, resulting in life span extension and increased resistance to stress. We also provide evidence that the observed life span extension is dependent on the transcriptional activity of Dauer formation abnormal/Forkhead box class O (DAF-16/FOXO), skinhead-1 (SKN-1), and heat shock factor-1 (HSF-1) factors through regulation of downstream longevity genes. We further show that the reported beneficial effects are not ubiquitous but they are dependent on the genetic context. Finally, we provide evidence that proteasome core activation might be a potential strategy to minimize protein homeostasis deficiencies underlying aggregation-related diseases, such as Alzheimer's disease (AD) or Huntington's disease (HD). In summary, this is the first report demonstrating that 20S core proteasome up-regulation in terms of both content and activity is feasible in a multicellular eukaryotic organism and that in turn this modulation promotes extension of organismal health span and life span. PMID:25395451

Chondrogianni, Niki; Georgila, Konstantina; Kourtis, Nikos; Tavernarakis, Nektarios; Gonos, Efstathios S

2015-02-01

113

Effect of habitat preference on frond life span in three Cyathea tree ferns  

NASA Astrophysics Data System (ADS)

It has been reported that plants living in various geographical areas had different physiological forms, as factors of microenvironment have strong impacts on physiological characters. However, the physiological characters of fronds have been scarcely reported in ferns. In this study, we investigated physiological differences in response to the habitat preference in the three tree ferns in northeast Taiwan, Cyathea lepifera, C. spinulosa, and C. podophylla, prefer to open site, edge of forest, and interior forest, respectively. The canopy openness above the individuals of C. lepifera, C. spinulosa and C. podophylla were 29.2 ± 14.10 , 7.0 ± 3.07 and 5.0 ± 2.24 %, respectively. Among three species, C. podophylla had the longest frond life span (13.0 ± 4.12 months) than the two others (C. lepifera (6.8 ± 1.29 months) and C. spinulosa (7.3 ±1.35 months). Our result supported the general patterns that shade intolerant species have a shorter leaf life span than shade tolerant species. The maximum net CO2 assimilation of C. lepifera, C. spinulosa and C. podophylla were 11.46 ± 1.34, 8.27 ± 0.69, and 6.34 ± 0.54 ?mol CO2 m-2 s-1, respectively. As well, C. lepifera had the highest photosynthetic light saturation point (LSP), while C. podophylla had the lowest LSP among these three tree ferns. These suggested that C. lepifera could be more efficient for capturing and utilizing light resources under the larger canopy openness condition than the other two species. We also found that frond C : N ratio were positively correlated with frond life span among species. C. podophylla, with the longest frond life span, had the highest frond C : N ratio (22.17 ± 1.95), which was followed by C. spinulosa (18.58 ± 1.37) and C. lepifera (18.68 ± 2.63) with shorter frond life span. The results were consistent to the theory that the fronds and leaves of shade intolerant species have high photosynthetic abilities with low C : N ratio. Key words: Canopy openness, frond life span, tree fern, Cyathea, frond C : N ratio

Chiu, Tzu Yun; Wang, Hsiang Hua; Lun Kuo, Yao; Kume, Tomonori

2013-04-01

114

Causes and consequences of variation in conifer leaf life-span  

SciTech Connect

Species with mutually supporting traits, such as high N{sub mass}, SLA, and A{sub mass}, and short leaf life-span, tend to inhabit either generally resource-rich environments or spatial and/or temporal microhabitats that are resource-rich in otherwise more limited habitats (e.g., {open_quotes}precipitation{close_quotes} ephemerals in warm deserts or spring ephemerals in the understory of temperate deciduous forests). In contrast, species with long leaf life-span often support foliage with low SLA, N{sub mass}, and A{sub mass}, and often grow in low-temperature limited, dry, and/or nutrient-poor environments. The contrast between evergreen and deciduous species, and the implications that emerge from such comparisons, can be considered a paradigm of modern ecological theory. However, based on the results of Reich et al. (1992) and Gower et al. (1993), coniferous species with foliage that persists for 9-10 years are likely to assimilate and allocate carbon and nutrients differently than other evergreen conifers that retain foliage for 2-3 years. Thus, attempts to contrast ecophysiological or ecosystem characteristics of evergreen versus deciduous life forms may be misleading, and pronounced differences among evergreen conifers may be ignored. Clearly, the deciduous-evergreen contrast, although useful in several ways, should be viewed from the broader perspective of a gradient in leaf life-span.

Reich, P.B.; Koike, T.; Gower, S.T.; Schoettle, A.W.

1995-07-01

115

Life Cycle, Host Range, and Reproduction of Heterodera betulae  

PubMed Central

Heterodera betulae, a cyst-forming nematode, originally recovered from roots of river birch in Arkansas, appears to have a limited host range. Of 80 plant species in 20 families tested, only five species of Betula and Cleome spinosa supported reproduction. The minimum time for a complete life cycle was 52 days at 28 C. No reproduction occurred at 31 C or above, and development was very slow below 20 C. Successful population propagations from single larvae demonstrated that males were not necessary for reproduction. PMID:19325673

Riggs, R. D.; Hirschmann, H.; Hamblen, M. L.

1969-01-01

116

Requirement of NAD and SIR2 for Life-Span Extension by Calorie Restriction in Saccharomyces cerevisiae  

Microsoft Academic Search

Calorie restriction extends life-span in a wide variety of organisms. Although it has been suggested that calorie restriction may work by reducing the levels of reactive oxygen species produced during respiration, the mechanism by which this regimen slows aging is uncertain. Here, we mimicked calorie restriction in yeast by physiological or genetic means and showed a substantial extension in life-span.

Su-Ju Lin; Pierre-Antoine Defossez; Leonard Guarente

2000-01-01

117

Having sons may shorten mother's life-span: anila : London, Wed Feb 27 2013, 19:09 hrs  

E-print Network

daughters prolong mothers' lives by helping in tasks such as obtaining food and rearing younger siblingsHaving sons may shorten mother's life-span: study anila : London, Wed Feb 27 2013, 19:09 hrs Producing sons is more stressful for mothers and could shorten their life spans, a study has suggested

Lummaa, Virpi

118

Leaf life span spectrum of tropical woody seedlings: effects of light and ontogeny and consequences for survival  

PubMed Central

Background and Aims Leaf life span is widely recognized as a key life history trait associated with herbivory resistance, but rigorous comparative data are rare for seedlings. The goal of this study was to examine how light environment affects leaf life span, and how ontogenetic development during the first year may influence leaf fracture toughness, lamina density and stem density that are relevant for herbivory resistance, leaf life span and seedling survival. Methods Data from three experiments encompassing 104 neotropical woody species were combined. Leaf life span, lamina and vein fracture toughness, leaf and stem tissue density and seedling survival were quantified for the first-year seedlings at standardized ontogenetic stages in shade houses and common gardens established in gaps and shaded understorey in a moist tropical forest in Panama. Mortality of naturally recruited seedlings till 1 year later was quantified in 800 1-m2 plots from 1994 to 2011. Key Results Median leaf life span ranged widely among species, always greater in shade (ranging from 151 to >1790 d in the understorey and shade houses) than in gaps (115–867 d), but with strong correlation between gaps and shade. Leaf and stem tissue density increased with seedling age, whereas leaf fracture toughness showed only a weak increase. All these traits were positively correlated with leaf life span. Leaf life span and stem density were negatively correlated with seedling mortality in shade, while gap mortality showed no correlation with these traits. Conclusions The wide spectrum of leaf life span and associated functional traits reflects variation in shade tolerance of first-year seedlings among coexisting trees, shrubs and lianas in this neotropical forest. High leaf tissue density is important in enhancing leaf toughness, a known physical defence, and leaf life span. Both seedling leaf life span and stem density should be considered as key functional traits that contribute to seedling survival in tropical forest understoreys. PMID:23532047

Kitajima, Kaoru; Cordero, Roberto A.; Wright, S. Joseph

2013-01-01

119

Life span of C57 mice as influenced by radiation dose, dose rate, and age at exposure  

SciTech Connect

This study was designed to measure the life shortening of C57BL/6J male mice as a result of exposure to five external doses from /sup 60/Co gamma radiation delivered at six different dose rates. Total doses ranged from 20 to 1620 rad at exposure rates ranging from 0.7 to 36,000 R/day. The ages of the mice at exposure were newborn, 2, 6, or 15 months. Two replications were completed. Although death was the primary endpoint, we did perform gross necropsies. The life span findings are variable, but we found no consistent shortening compared to control life spans. Therefore, we cannot logically extrapolate life shortening to lower doses, from the data we have obtained. In general, the younger the animals were at the beginning of exposure, the longer their life spans were compared to those of controls. This relationship weakened at the higher doses and dose rates, as mice in these categories tended not to have significantly different life spans from controls. Using life span as a criterion, we find this study suggests that some threshold dosage may exist beyond which effects of external irradiation may be manifested. Up to this threshold, there is no shortening effect on life span compared to that of control mice. Our results are in general agreement with the results of other researchers investigating human and other animal life span effects on irradiation.

Spalding, J.F.; Thomas, R.G.; Tietjen, G.L.

1982-10-01

120

Body Image Across the Life Span in Adult Women: The Role of Self-Objectification  

Microsoft Academic Search

This study aimed to investigate women's body image across the entire life span from within the theoretical perspective provided by objectification theory (B. L. Fredrickson & T.-A. Roberts, 1997). In a cross-sectional study, a sample of 322 women ranging in age from 20 to 84 years completed a questionnaire measuring body dissatisfaction, self-objectification, and its proposed consequences. Although body dissatisfaction

Marika Tiggemann; Jessica E. Lynch

2001-01-01

121

Dependence of the life span of the honeybee ( Apis mellifica ) upon flight performance and energy consumption  

Microsoft Academic Search

The life span of worker-honeybees is determined by the duration of the hive-period and of the foraging period (Figs. 1,2). The duration of the forgaing period is regulated in the following way: Total flight performance of the individual bee seems to be fixed. Daily flight performance strongly affects total flight duration. High daily flight performance decreases maximal flight duration and

Angelika Neukirch

1982-01-01

122

Attachment and the Processing of Social Information Across the Life Span: Theory and Evidence  

Microsoft Academic Search

Researchers have used J. Bowlby's (1969\\/1982, 1973, 1980, 1988) attachment theory frequently as a basis for examining whether experiences in close personal relationships relate to the processing of social information across childhood, adolescence, and adulthood. We present an integrative life-span–encompassing theoretical model to explain the patterns of results that have emerged from these studies. The central proposition is that individuals

Matthew J. Dykas; Jude Cassidy

2011-01-01

123

Prolongation of life span in hypertensive rats by dietary interventions. Effects of garlic and linseed oil  

Microsoft Academic Search

The effects of long-term dietary application of garlic (dried powder, 0.5% in weight of standard chow; G group) or linseed oil (2.5%; L group) as well as a combination of both interventions (L+G group) on the life span of hypertensive rats (SHR SP) was investigated. A further group fed with standard chow served as control (C). The dietary interventions were

M. Brändle; S. Makdessi; R. K. Weber; K. Dietz; R. Jacob

1997-01-01

124

RERF Life Span Study, Adult Health Study, and F1 Cohorts (Hiroshima and Nagasaki)  

Cancer.gov

The main cohort, called the Life Span Study (LSS), consisted of about 120,000 persons of all ages and both genders in 1950 of whom more than 90,000 were exposed to atomic bomb radiation, with a wide range of exposure doses. About 45,000 LSS participants completed questionnaires in the late 1960s and periodically since then on sociodemographic, lifestyle, and other disease risk factors.

125

Clinical performance of the Copper T200B IUD after reinsertion following life-span expiration  

Microsoft Academic Search

The purpose of this study was to evaluate the first year clinical performance of the TCu200B IUD in a cohort of women who had the IUD re-inserted immediately after a removal for life-span expiration, compared with a group of initial acceptors, and a cohort of women who continued using the device for more than 60 months. The sample consisted of

J. Díaz; L. Bahamondes; N. M. Marchi; C. A. Petta; M. Díaz; D. Faúndes

1994-01-01

126

Reproductive and early life stages pathology - Histopathology workshop report  

USGS Publications Warehouse

Pathology occurring during reproduction and larval development represents an important part of the life cycle of fish, and the diseases that affect eggs and larvae often result in significant losses. However, mortality during this period is frequently ignored or poorly researched as the temptation is to replace the losses rather than investigate the causes. A histopathology workshop organised at the newly refurnished laboratory within the Danish Veterinary School was an opportunity to discuss the pathology of selected diseases associated with Reproductive and Early Life Stages Pathology. Several people also kindly provided reference slides.

Bruno, D.W.; Nowak, B.; Elliott, D.G.

2006-01-01

127

The conserved NAD(H)-dependent corepressor CTBP-1 regulates Caenorhabditis elegans life span  

PubMed Central

CtBP (C-terminal binding protein) is an evolutionarily conserved NAD(H)-dependent transcriptional corepressor, whose activity has been shown to be regulated by the NAD/NADH ratio. Although recent studies have provided significant new insights into mechanisms by which CtBP regulates transcription, the biological function of CtBP remains incompletely understood. Here, we report that genetic inactivation of the Caenorhabditis elegans homolog, ctbp-1, results in life span extension, which is suppressed by reintroduction of the ctbp-1 genomic DNA encoding wild-type but not NAD(H)-binding defective CTBP-1 protein. We show that CTBP-1 possibly modulates aging through the insulin/IGF-1 signaling pathway, dependent on the forkhead transcription factor DAF-16, but independent of the NAD-dependent histone deacetylase SIR-2.1. Genome-wide microarray analysis identifies >200 potential CTBP-1 target genes. Importantly, RNAi inhibition of a putative triacylglycerol lipase gene lips-7(C09E8.2) but not another lipase suppresses the life span extension phenotype. Consistently, metabolic analysis shows that the triacylglycerol level is reduced in the ctbp-1 deletion mutant, which is restored to the wild-type level by RNAi inhibition of lips-7. Taken together, our data suggest that CTBP-1 controls life span probably through the regulation of lipid metabolism. PMID:19164523

Chen, Shuzhen; Whetstine, Johnathan R.; Ghosh, Salil; Hanover, John A.; Gali, Reddy R.; Grosu, Paul; Shi, Yang

2009-01-01

128

Psychosocial stressors and the short life spans of legendary jazz musicians.  

PubMed

Mean age at death of 168 legendary jazz musicians and 100 renowned classical musicians were compared to examine whether psychosocial stressors such as severe substance abuse, haphazard working conditions, lack of acceptance of jazz as an art form in the United States, marital and family discord, and a vagabond life style may have contributed to shortened life spans for the jazz musicians. Analysis indicated that the jazz musicians died at an earlier age (57.2 yr.) than the classical musicians (73.3 yr.). PMID:10833735

Patalano, F

2000-04-01

129

Lynx reproduction--long-lasting life cycle of corpora lutea in a feline species.  

PubMed

A review of lynxes' reproductive biology and comparison between the reproductive cycles of the domestic cat and lynxes is presented. Three of the four lynx species (the bobcat excluded) express quite similar reproductive pattern (age at sexual maturity, estrus and pregnancy length, litter size). Similarly to the domestic cat, the bobcat is polyestric and can have more than one litter per year. Domestic cats and many other felid species are known to express anovulatory, pregnant and pseudo-pregnant reproductive cycles in dependence on ovulation induction and fertilization. The formation of corpora lutea (CLs) occurs after ovulation. In pregnant animals, luteal function ends with parturition, whereas during pseudo-pregnancy a shorter life span and lower hormone secretion are observed. The life cycle of corpora lutea in Eurasian lynxes is different from the pattern described in domestic cats. Lynx CLs produce progestagens in distinctive amounts permanently for at least two years, regardless of their origin (pregnancy or pseudo-pregnancy). It is suggested that long-lasting CLs induce a negative feedback to inactivate folliculogenesis, turning a normally polyestric cycle observed in most felids into a monoestric cycle in lynxes. PMID:24856466

Jewgenow, Katarina; Painer, Johanna; Amelkina, Olga; Dehnhard, Martin; Goeritz, Frank

2014-04-01

130

Life Satisfaction, Self-Esteem, and Subjective Age in Women across the Life Span  

ERIC Educational Resources Information Center

A study of 320 women, ages 21 to 69, explored the relations among relationship status, subjective age, self-esteem, and life satisfaction. Women in married or partnered relationships had higher levels of life satisfaction than did single women. Women in their 30s and 40s had significantly lower levels of life satisfaction than did other age…

Borzumato-Gainey, Christine; Kennedy, Alison; McCabe, Beth; Degges-White, Suzanne

2009-01-01

131

Shorter Life Span of Microorganisms and Plants as a Consequence of Shielded Magnetic Environment  

NASA Astrophysics Data System (ADS)

The geomagnetic field is an essential environmental factor for life and health on this planet. In order to survey how magnetic fields affect the life span and the nitrogenase (an iron-sulphur enzyme) activity of Azotobacter chroococcum as well as the life span, the main organic synthesis and the water balance of plants (22 species), the biological tests were incubated under shielded magnetic field and also in normal geo-magnetic environment. The shielding level was about 10-6 of the terrestrial magnetic field.Life cycles of all organisms require the co-ordinated control of a complex set of interlocked physiological processes and metabolic pathways. Such processes are likely to be regulated by a large number of genes. Our researches suggest that the main point in biological structures, which seems to be affected by the low magnetic environment, is the water molecule. Magnetic field induces a molecular alignment. Under shielded conditions, unstructured water molecules with fewer hydrogen bonds, which are producing a more reactive environment, are occurring. As compared to control, the life span of both microorganisms and plants was shorter in shielded environment. A higher nitrogenase affinity for the substrate was recorded in normal geo-magnetic field compared to low magnetic field. The synthesis of carbohydrates, lipids, proteins and enzymes was modified under experimental conditions. The stomatal conductance was higher between 158 and 300% in shielded environment indicating an important water loss from the plant cells.Our results support the idea that the shielded magnetic environment induces different reactions depending on the time of exposure and on the main metabolic pathways of the cells.

Dobrota, C.; Piso, I. M.; Bathory, D.

132

Formal Models of Reproduction: from Computer Viruses to Artificial Life  

E-print Network

Formal Models of Reproduction: from Computer Viruses to Artificial Life Thesis submitted. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.1.1 Motivations of Computer Virus Writers . . . . . . . . . . . . . . 2 1.1.2 A Short History of Computer Viruses . . . . . . . . . . . . . . . 3 1.1.3 Academic Study of Computer Viruses

Atkinson, Katie

133

Dead or Alive: Deformed Wing Virus and Varroa destructor Reduce the Life Span of Winter Honeybees  

PubMed Central

Elevated winter losses of managed honeybee colonies are a major concern, but the underlying mechanisms remain controversial. Among the suspects are the parasitic mite Varroa destructor, the microsporidian Nosema ceranae, and associated viruses. Here we hypothesize that pathogens reduce the life expectancy of winter bees, thereby constituting a proximate mechanism for colony losses. A monitoring of colonies was performed over 6 months in Switzerland from summer 2007 to winter 2007/2008. Individual dead workers were collected daily and quantitatively analyzed for deformed wing virus (DWV), acute bee paralysis virus (ABPV), N. ceranae, and expression levels of the vitellogenin gene as a biomarker for honeybee longevity. Workers from colonies that failed to survive winter had a reduced life span beginning in late fall, were more likely to be infected with DWV, and had higher DWV loads. Colony levels of infection with the parasitic mite Varroa destructor and individual infections with DWV were also associated with reduced honeybee life expectancy. In sharp contrast, the level of N. ceranae infection was not correlated with longevity. In addition, vitellogenin gene expression was significantly positively correlated with ABPV and N. ceranae loads. The findings strongly suggest that V. destructor and DWV (but neither N. ceranae nor ABPV) reduce the life span of winter bees, thereby constituting a parsimonious possible mechanism for honeybee colony losses. PMID:22179240

Evans, Jay D.; Chen, Yan Ping; Gauthier, Laurent; Neumann, Peter

2012-01-01

134

Personality development across the life span: longitudinal analyses with a national sample from Germany.  

PubMed

Longitudinal data from a national sample of Germans (N = 20,434) were used to evaluate stability and change in the Big Five personality traits. Participants completed a brief measure of personality twice, 4 years apart. Structural equation modeling techniques were used to establish measurement invariance over time and across age groups. Substantive questions about differential (or rank-order) and mean-level stability and change were then evaluated. Results showed that differential stability was relatively strong among all age groups but that it increased among young adults, peaked in later life, and then declined among the oldest old. Patterns of mean-level change showed that Extraversion and Openness declined over the life span, whereas Agreeableness increased. Mean levels of Conscientiousness increased among young adults and then decreased among older adults. Trajectories for Neuroticism were relatively flat, with slight increases during middle age and a slight decline in late life. PMID:21707197

Lucas, Richard E; Donnellan, M Brent

2011-10-01

135

Phenotypic plasticity of life history traits in relation to reproductive strategies in Boa constrictor occidentalis  

Microsoft Academic Search

The close connection between reproductive ecology and life history in snakes leads to trade-offs between reproductive and\\u000a other life-history traits. Optimal energy allocation to growth and reproduction is a key factor to determine life history\\u000a structure. Therefore, elucidating the relationship between body size variations and reproductive characters is essential for\\u000a a better understanding of life-history plasticity. The aim of this

Margarita Chiaraviglio

136

eRapa Restores A Normal Life Span in a FAP Mouse Model  

PubMed Central

Mutation of a single copy of the adenomatous polyposis coli (APC) gene results in familial adenomatous polyposis (FAP), which confers an extremely high risk for colon cancer. ApcMin/+ mice exhibit multiple intestinal neoplasia (MIN) that causes anemia and death from bleeding by 6 months. Mechanistic target of rapamycin complex 1 (mTORC1) inhibitors were shown to improve ApcMin/+ mouse survival when administered by oral gavage or added directly to the chow, but these mice still died from neoplasia well short of a natural life span. The National Institute of Aging Intervention Testing Program showed that enterically targeted rapamycin (eRapa) extended life span for wild type genetically heterogeneous mice in part by inhibiting age-associated cancer. We hypothesized that eRapa would be effective in preventing neoplasia and extend survival of ApcMin/+ mice. We show that eRapa improved survival for ApcMin/+ mice in a dose-dependent manner. Remarkably, and in contrast to previous reports, most of the ApcMin/+ mice fed 42 ppm eRapa lived beyond the median life span reported for wild type syngeneic mice. Furthermore, chronic eRapa did not cause detrimental immune effects in mouse models of cancer, infection or autoimmunity; thus, assuaging concerns that chronic rapamycin treatment suppresses immunity. Our studies suggest that a novel formulation (enteric targeting) of a well-known and widely used drug (rapamycin) can dramatically improve its efficacy in targeted settings. eRapa or other mTORC1 inhibitors could serve as effective cancer preventatives for people with FAP without suppressing the immune system, thus reducing the dependency on surgery as standard therapy. PMID:24282255

Hasty, Paul; Livi, Carolina B.; Dodds, Sherry G.; Jones, Diane; Strong, Randy; Javors, Martin; Fischer, Kathleen E.; Sloane, Lauren; Murthy, Kruthi; Hubbard, Gene; Sun, Lishi; Hurez, Vincent; Curiel, Tyler J.; Sharp, Zelton Dave

2014-01-01

137

eRapa restores a normal life span in a FAP mouse model.  

PubMed

Mutation of a single copy of the adenomatous polyposis coli (APC) gene results in familial adenomatous polyposis (FAP), which confers an extremely high risk for colon cancer. Apc(Min/+) mice exhibit multiple intestinal neoplasia (MIN) that causes anemia and death from bleeding by 6 months. Mechanistic target of rapamycin complex 1 (mTORC1) inhibitors were shown to improve Apc(Min/+) mouse survival when administered by oral gavage or added directly to the chow, but these mice still died from neoplasia well short of a natural life span. The National Institute of Aging Intervention Testing Program showed that enterically targeted rapamycin (eRapa) extended life span for wild-type genetically heterogeneous mice in part by inhibiting age-associated cancer. We hypothesized that eRapa would be effective in preventing neoplasia and extend survival of Apc(Min/+) mice. We show that eRapa improved survival of Apc(Min/+) mice in a dose-dependent manner. Remarkably, and in contrast to previous reports, most of the Apc(Min/+) mice fed 42 parts per million eRapa lived beyond the median life span reported for wild-type syngeneic mice. Furthermore, chronic eRapa did not cause detrimental immune effects in mouse models of cancer, infection, or autoimmunity, thus assuaging concerns that chronic rapamycin treatment suppresses immunity. Our studies suggest that a novel formulation (enteric targeting) of a well-known and widely used drug (rapamycin) can dramatically improve its efficacy in targeted settings. eRapa or other mTORC1 inhibitors could serve as effective cancer preventatives for people with FAP without suppressing the immune system, thus reducing the dependency on surgery as standard therapy. PMID:24282255

Hasty, Paul; Livi, Carolina B; Dodds, Sherry G; Jones, Diane; Strong, Randy; Javors, Martin; Fischer, Kathleen E; Sloane, Lauren; Murthy, Kruthi; Hubbard, Gene; Sun, Lishi; Hurez, Vincent; Curiel, Tyler J; Sharp, Zelton Dave

2014-01-01

138

Photosynthetic thermotolerance of woody savanna species in China is correlated with leaf life span  

PubMed Central

Background and Aims Photosynthetic thermotolerance (PT) is important for plant survival in tropical and sub-tropical savannas. However, little is known about thermotolerance of tropical and sub-tropical wild plants and its association with leaf phenology and persistence. Longer-lived leaves of savanna plants may experience a higher risk of heat stress. Foliar Ca is related to cell integrity of leaves under stresses. In this study it is hypothesized that (1) species with leaf flushing in the hot-dry season have greater PT than those with leaf flushing in the rainy season; and (2) PT correlates positively with leaf life span, leaf mass per unit area (LMA) and foliar Ca concentration ([Ca]) across woody savanna species. Methods The temperature-dependent increase in minimum fluorescence was measured to assess PT, together with leaf dynamics, LMA and [Ca] for a total of 24 woody species differing in leaf flushing time in a valley-type savanna in south-west China. Key Results The PT of the woody savanna species with leaf flushing in the hot-dry season was greater than that of those with leaf flushing in the rainy season. Thermotolerance was positively associated with leaf life span and [Ca] for all species irrespective of the time of flushing. The associations of PT with leaf life span and [Ca] were evolutionarily correlated. Thermotolerance was, however, independent of LMA. Conclusions Chinese savanna woody species are adapted to hot-dry habitats. However, the current maximum leaf temperature during extreme heat stress (44·3 °C) is close to the critical temperature of photosystem II (45·2 °C); future global warming may increase the risk of heat damage to the photosynthetic apparatus of Chinese savanna species. PMID:22875810

Zhang, Jiao-Lin; Poorter, L.; Hao, Guang-You; Cao, Kun-Fang

2012-01-01

139

Caffeine extends life span, improves healthspan, and delays age-associated pathology in Caenorhabditis elegans  

PubMed Central

Background The longevity of an organism is influenced by both genetic and environmental factors. With respect to genetic factors, a significant effort is being made to identify pharmacological agents that extend life span by targeting pathways with a defined role in the aging process. On the environmental side, the molecular mechanisms responsible for the positive influence of interventions such as dietary restriction are being explored. The environment experienced by humans in modern societies already contains countless compounds that may influence longevity. Understanding the role played by common compounds that substantially affect the aging process will be critical for predicting and interpreting the outcome of introducing new interventions. Caffeine is the most widely used psychoactive drug worldwide. Prior studies in flies, worms, and mice indicate that caffeine may positively impact age-associated neurodegenerative pathology, such as that observed in Alzheimer’s disease. Results Here we report that caffeine is capable of extending life span and improving healthspan in Caenorhabditis elegans, a finding that is in agreement with a recently published screen looking for FDA-approved compounds capable of extending worm life span. Life span extension using caffeine displays epistatic interaction with two known longevity interventions: dietary restriction and reduced insulin signaling. Caffeine treatment also delays pathology in a nematode model of polyglutamine disease. Conclusions The identification of caffeine as a relevant factor in aging and healthspan in worms, combined with prior work in both humans and rodents linking caffeine consumption to reduced risk of age-associated disease, suggests that caffeine may target conserved longevity pathways. Further, it may be important to consider caffeine consumption when developing clinical interventions, particularly those designed to mimic dietary restriction or modulate insulin/IGF-1-like signaling. The positive impact of caffeine on a worm model of polyglutamine disease suggests that chronic caffeine consumption may generally enhance resistance to proteotoxic stress and may be relevant to assessing risk and developing treatments for human diseases like Alzheimer’s and Huntington’s disease. Future work addressing the relevant targets of caffeine in models of aging and healthspan will help to clarify the underlying mechanisms and potentially identify new molecular targets for disease intervention. PMID:24764514

2012-01-01

140

[Mechanisms of life span polymorphism maintenance in the house fly laboratory strains].  

PubMed

Assortative mating and hypervariability as the result of genomic stress, caused by selection, appear the main components of the mechanism of intrapopulation polymorphism maintenance. Activation of genome transposable elements has contributed significantly to increasing of variability provoked by inbreeding. Copy number of transposone Hermes DNA evaluation in somatic tissues of Musca domestica individuals from the strains differ by the life span at all developmental stages used as the criterion of genome stability. Investigations funded by RFBR 12-04-01450-a and 11-04-97005-r_povolzhje_a. PMID:24738245

Nikonorov, Iu M; Ben'kovskaia, G V

2013-01-01

141

Improvement\\/Maintenance and Reorientation as Central Features of Coping with Major Life Change and Loss: Contributions of Three Life-Span Theories  

Microsoft Academic Search

This article focuses on the common and unique contributions of three major life-span theories in addressing improvement\\/maintenance and reorientation, which represent central processes of coping with major life change and loss. For this purpose, we review and compare the dual-process model of assimilative and accommodative coping, the model of selection, optimization, and compensation, and the life-span theory of control. Although

Kathrin Boerner; Daniela Jopp

2007-01-01

142

Spermatozoid life-span of two brown seaweeds, Saccharina japonica and Undaria pinnatifida, as measured by fertilization efficiency  

NASA Astrophysics Data System (ADS)

During sexual reproduction of seaweeds, spermatozoid (sperm) discharge is triggered by chemical messengers (pheromones) released by the female gametes. The chemotactic ability of the sperm ensures fertilization success. Using unialgal male and female gametophyte material under designated standard gametogenesis testing (SGT) conditions, the potential life-span of the sperm of two seaweeds, Saccharina japonica and Undaria pinnatifida, was assessed by their ability to fertilize eggs. Results show that within 20-30 min after being discharged, sperm of both species could complete fertilization without an apparent decline in fertilization rate. Although fertilization rate 60-120 min after sperm discharge dropped significantly in both species, some sperm were viable enough to fertilize the eggs. In S. japonica, at 12°C, some sperm were able to fertilize eggs up to 12 h after discharge. In both species, egg discharge rates (EDR) in the male and female mixed positive controls were significantly higher than those of all the sperm-testing groups. Doubling the seeded male gametophytes of S. japonica in the SGT tests significantly increased the EDR, further confirming the effect of the presence of the male on the female in terms of facilitating egg discharge from oogonia.

Li, Jing; Pang, Shaojun; Liu, Feng; Shan, Tifeng; Gao, Suqin

2013-07-01

143

Best squirrels trade a long life for an early reproduction.  

PubMed

Age at primiparity plays a crucial role in population dynamics and life-history evolution. Long-term data on female North American red squirrels were analysed to study the fitness consequences of delaying first reproduction. Early breeders were born earlier, had a higher breeding success and achieved a higher lifetime reproductive success than females who delayed their first reproduction, which suggests a higher quality of early breeders. However, early breeders had similar mass when tagged, and similar number of food caches available at one year of age as late breeders. Nevertheless, we found evidence of survival costs of early primiparity. Early breeders had a lower survival between one and two years of age than late breeders and a lower lifespan. Our study points out that two reproductive tactics co-occurred in this population: a tactic based on early maturity at the cost of a lower survival versus a tactic based on delayed maturity and long lifespan. High quality individuals express the most profitable tactic by breeding early whereas low quality individuals do the best of a bad job by delaying their first reproduction. PMID:16928640

Descamps, Sébastien; Boutin, Stan; Berteaux, Dominique; Gaillard, Jean-Michel

2006-09-22

144

Best squirrels trade a long life for an early reproduction  

PubMed Central

Age at primiparity plays a crucial role in population dynamics and life-history evolution. Long-term data on female North American red squirrels were analysed to study the fitness consequences of delaying first reproduction. Early breeders were born earlier, had a higher breeding success and achieved a higher lifetime reproductive success than females who delayed their first reproduction, which suggests a higher quality of early breeders. However, early breeders had similar mass when tagged, and similar number of food caches available at one year of age as late breeders. Nevertheless, we found evidence of survival costs of early primiparity. Early breeders had a lower survival between one and two years of age than late breeders and a lower lifespan. Our study points out that two reproductive tactics co-occurred in this population: a tactic based on early maturity at the cost of a lower survival versus a tactic based on delayed maturity and long lifespan. High quality individuals express the most profitable tactic by breeding early whereas low quality individuals do the best of a bad job by delaying their first reproduction. PMID:16928640

Descamps, Sébastien; Boutin, Stan; Berteaux, Dominique; Gaillard, Jean-Michel

2006-01-01

145

NRF2 deficiency reduces life span of mice administered thoracic irradiation  

PubMed Central

Subsets of cancer survivors who have been subjected to thoracic irradiation face the prospect of developing pulmonary injury. Radiation-induced pulmonary fibrosis is an insidious injury that presents 6 to 24 months after irradiation and continues to progress over a period of years. TGF-? and reactive oxygen species contribute significantly to the pathogenesis of this injury. The transcription factor NRF2 controls antioxidant gene expression and therefore regulates the cellular oxidant burden. This work demonstrates an additional paradigm for NRF2: suppression of TGF-?-mediated signaling, assessed by measuring expression of a surrogate TGF-?1 target gene (PAI-1) in lung fibroblasts. Thoracic irradiation of Nfe2l2 (?/?) mice resulted in rapid expression of PAI-1 and FSP-1 compare to irradiated wild type mice. Examination of lung tissue 16 weeks after thoracic irradiation of Nfe2l2 (?/?) mice revealed the presence of distended alveoli and decreased numbers of alveoli compared to wild type mice. Suppression of NRF2 expression shortened life span in mice administered 16 Gy to the thorax. Nfe2l2 (+/?) and (?/?) mice exhibited a mean life span of 176 days compared to wild type mice that lived an average of 212 days. These novel results identify NRF2 as a susceptibility factor for development of late tissue injury. PMID:21712086

Travis, Elizabeth L.; Rachakonda, Girish; Zhou, Xinhui; Korhonen, Katrina; Sekhar, Konjeti R; Biswas, Swati; Freeman, Michael L.

2011-01-01

146

Rapamycin extends life span of Rb1+/? mice by inhibiting neuroendocrine tumors  

PubMed Central

Chronic treatment of mice with an enterically released formulation of rapamycin (eRapa) extends median and maximum life span, partly by attenuating cancer. The mechanistic basis of this response is not known. To gain a better understanding of these in vivo effects, we used a defined preclinical model of neuroendocrine cancer, Rb1+/? mice. Previous results showed that diet restriction (DR) had minimal or no effect on the lifespan of Rb1+/? mice, suggesting that the beneficial response to DR is dependent on pRb1. Since long-term eRapa treatment may at least partially mimic chronic DR in lifespan extension, we predicted that it would have a minimal effect in Rb1+/? mice. Beginning at 9 weeks of age until death, we fed Rb1+/? mice a diet without or with eRapa at 14 mg/kg food, which results in an approximate dose of 2.24 mg/kg body weight per day, and yielded rapamycin blood levels of about 4 ng/ml. Surprisingly, we found that eRapa dramatically extended life span of both female and male Rb1+/? mice, and slowed the appearance and growth of pituitary and decreased the incidence of thyroid tumors commonly observed in these mice. In this model, eRapa appears to act differently than DR, suggesting diverse mechanisms of action on survival and anti-tumor effects. In particular the beneficial effects of rapamycin did not depend on the dose of Rb1. PMID:23454836

Livi, Carolina B.; Hardman, Rulon L.; Christy, Barbara A.; Dodds, Sherry G.; Jones, Diane; Williams, Charnae; Strong, Randy; Bokov, Alex; Javors, Martin A.; Ikeno, Yuji; Hubbard, Gene; Hasty, Paul; Sharp, Zelton Dave

2013-01-01

147

Yeast endosulfines control entry into quiescence and chronological life span by inhibiting protein phosphatase 2A.  

PubMed

The TORC1 and PKA protein kinases are central elements of signaling networks that regulate eukaryotic cell proliferation in response to growth factors and/or nutrients. In yeast, attenuation of signaling by these kinases following nitrogen and/or carbon limitation activates the protein kinase Rim15, which orchestrates the initiation of a reversible cellular quiescence program to ensure normal chronological life span. The molecular elements linking Rim15 to distal readouts including the expression of Msn2/4- and Gis1-dependent genes involve the endosulfines Igo1/2. Here, we show that Rim15, analogous to the greatwall kinase in Xenopus, phosphorylates endosulfines to directly inhibit the Cdc55-protein phosphatase 2A (PP2A(Cdc55)). Inhibition of PP2A(Cdc55) preserves Gis1 in a phosphorylated state and consequently promotes its recruitment to and activation of transcription from promoters of specific nutrient-regulated genes. These results close a gap in our perception of and delineate a role for PP2A(Cdc55) in TORC1-/PKA-mediated regulation of quiescence and chronological life span. PMID:23273919

Bontron, Séverine; Jaquenoud, Malika; Vaga, Stefania; Talarek, Nicolas; Bodenmiller, Bernd; Aebersold, Ruedi; De Virgilio, Claudio

2013-01-31

148

[Psychoneuroimmunology of the life span: impact of childhood stress on immune dysregulation and inflammatory disease in later life].  

PubMed

Studies have shown clearly that childhood mistreatment, abuse and neglect are associated with severe inflammatory disease in adulthood (e.?g. cancer, heart disease, autoimmune disorder) and shortened life span. This review deals with the psychoneuroimmunological pathways of this connection. It shows that chronic stressors interfere very early in life with those protective mechanisms of the biological stress system that normally down-regulate potentially harmful inflammation. In the long term, serious inflammatory diseases, such as allergic asthma, can result. In this review, the pathogenetic connections between allergic asthma and early stress and stress system dysfunction are discussed. As our understanding of the dysfunctional psychophysiological mechanisms of inflammatory disease increases, psychodiagnostic and psychotherapeutic intervention in the treatment of physical disease will become more specific. PMID:24248864

Schubert, Christian

2014-05-01

149

Biological impact of auditory expertise across the life span: musicians as a model of auditory learning  

PubMed Central

Experience-dependent characteristics of auditory function, especially with regard to speech-evoked auditory neurophysiology, have garnered increasing attention in recent years. This interest stems from both pragmatic and theoretical concerns as it bears implications for the prevention and remediation of language-based learning impairment in addition to providing insight into mechanisms engendering experience-dependent changes in human sensory function. Musicians provide an attractive model for studying the experience-dependency of auditory processing in humans due to their distinctive neural enhancements compared to nonmusicians. We have only recently begun to address whether these enhancements are observable early in life, during the initial years of music training when the auditory system is under rapid development, as well as later in life, after the onset of the aging process. Here we review neural enhancements in musically trained individuals across the life span in the context of cellular mechanisms that underlie learning, identified in animal models. Musicians’ subcortical physiologic enhancements are interpreted according to a cognitive framework for auditory learning, providing a model by which to study mechanisms of experience-dependent changes in auditory function in humans. PMID:23988583

Strait, Dana L.; Kraus, Nina

2013-01-01

150

Gas and dust emission from comets and life spans of active areas on their rotating nuclei  

NASA Technical Reports Server (NTRS)

Outgassing and dust emission from discrete regions on the nuclei of comets are investigated with regard to the processes of activation, dormancy, reactivation, and extinction. With regard to P/Halley, P/Encke, P/Tempel 2, P/Machholz, P/Takamizawa, Bowell and some other new comets, the evolution of one active region of the nucleus surface appears to be independent of the evolution of another active region. The traditional concept of deactivation as a slow and monolithic process needs to be replaced with a more dynamic concept of intermittent periods of dormancy and reactivation of individual vents, varying in size. Life spans of discrete sources of activity are estimated to be at a few hundred revolutions about the sun for comets with perihelia at heliocentric distances of less than 2 AU, if the bulk density is very low.

Sekanina, Z.

1990-01-01

151

Niacin-bound chromium increases life span in Zucker Fatty Rats.  

PubMed

Avoiding insulin resistance (IR) associated with aging might lengthen life span based on previous studies using caloric-restricted animals. We assessed whether consuming niacin-bound chromium (NBC) alone or in a formula containing other so-called "insulin sensitizers" would overcome various manifestations of aging and extend life span in Zucker Fatty Rats (ZFR). We compared many metabolic parameters of ZFR fed NBC alone (n=12) or NBC in a unique formula (n=10) to a control group (n=10). In addition to NBC, the formula contained Allium sativum, Momordica charantia, Trigonella foenum-graecum and Gymnema sylvestre. The formula group received roughly 1/2 as much NBC daily as the NBC group. At week 44, all rats still lived, and no abnormalities in blood count (CBC), renal, or liver functions were found. In the two treatment groups compared to control, circulating glucose levels were significantly lower, with a trend toward lower HbA1C. Relatively elevated cholesterol and triglyceride concentrations occurred in the formula group. Compared to control, the NBC group had increased average lifespan (21.8%), median lifespan (14.1%), 30th percentile survival (19.6%), and maximum lifespan (22%). Despite similar beneficial effects on the glucose and blood pressure systems, a difference in aging was also found when the NBC group was compared to the formula group. When all rats in the other two groups had died, four in the NBC group continued to live at least a month longer. We attribute lack of a similar aging effect in the formula group to either lower dosing of NBC and/or that various ingredients in the formula counteracted the antiaging effect(s) of NBC. PMID:21930012

Preuss, Harry G; Echard, Bobby; Clouatre, Dallas; Bagchi, Debasis; Perricone, Nicholas V

2011-10-01

152

Virtual navigation strategies from childhood to senescence: evidence for changes across the life span  

PubMed Central

This study sought to investigate navigational strategies across the life span, by testing 8-years old children to 80-years old healthy older adults on the 4 on 8 virtual maze (4/8VM). The 4/8VM was previously developed to assess spontaneous navigational strategies, i.e., hippocampal-dependent spatial strategies (navigation by memorizing relationships between landmarks) versus caudate nucleus-dependent response strategies (memorizing a series of left and right turns from a given starting position). With the 4/8VM, we previously demonstrated greater fMRI activity and gray matter in the hippocampus of spatial learners relative to response learners. A sample of 599 healthy participants was tested in the current study. Results showed that 84.4% of children, 46.3% of young adults, and 39.3% of older adults spontaneously used spatial strategies (p < 0.0001). Our results suggest that while children predominantly use spatial strategies, the proportion of participants using spatial strategies decreases across the life span, in favor of response strategies. Factors promoting response strategies include repetition, reward and stress. Since response strategies can result from successful repetition of a behavioral pattern, we propose that the increase in response strategies is a biological adaptive mechanism that allows for the automatization of behavior such as walking in order to free up hippocampal-dependent resources. However, the down-side of this shift from spatial to response strategies occurs if people stop building novel relationships, which occurs with repetition and routine, and thereby stop stimulating their hippocampus. Reduced fMRI activity and gray matter in the hippocampus were shown to correlate with cognitive deficits in normal aging. Therefore, these results have important implications regarding factors involved in healthy and successful aging. PMID:23162463

Bohbot, Veronique D.; McKenzie, Sam; Konishi, Kyoko; Fouquet, Celine; Kurdi, Vanessa; Schachar, Russel; Boivin, Michel; Robaey, Philippe

2012-01-01

153

Cancer risk among atomic bomb survivors. The RERF Life Span Study. Radiation Effects Research Foundation  

SciTech Connect

This article summarizes the risk of cancer among the survivors of the atomic bombing of Hiroshima and Nagasaki. We focus primarily on the risk of death from cancer among individuals in the Life Span Study sample of the Radiation Effects Research Foundation from 1950 through 1985 based on recently revised dosimetry procedures. We report the risk of cancer other than leukemia among the atomic bomb survivors. We note that the number of excess deaths of radiation-induced malignant tumors other than leukemia increases with age. Survivors who were exposed in the first or second decade of life have just entered the cancer-prone age and have so far exhibited a high relative risk in association with radiation dose. Whether the elevated risk will continue or will fall with time is not yet clear, although some evidence suggests that the risk may be declining. It is important to continue long-term follow-up of this cohort to document the changes with time since exposure and to provide direct rather than projected risks over the lifetime of an exposed individual.

Shimizu, Y.; Schull, W.J.; Kato, H. (Radiation Effects Research Foundation, Hiroshima (Japan))

1990-08-01

154

Aging Theories for Establishing Safe Life Spans of Airborne Critical Structural Components  

NASA Technical Reports Server (NTRS)

New aging theories have been developed to establish the safe life span of airborne critical structural components such as B-52B aircraft pylon hooks for carrying air-launch drop-test vehicles. The new aging theories use the equivalent-constant-amplitude loading spectrum to represent the actual random loading spectrum with the same damaging effect. The crack growth due to random loading cycling of the first flight is calculated using the half-cycle theory, and then extrapolated to all the crack growths of the subsequent flights. The predictions of the new aging theories (finite difference aging theory and closed-form aging theory) are compared with the classical flight-test life theory and the previously developed Ko first- and Ko second-order aging theories. The new aging theories predict the number of safe flights as considerably lower than that predicted by the classical aging theory, and slightly lower than those predicted by the Ko first- and Ko second-order aging theories due to the inclusion of all the higher order terms.

Ko, William L.

2003-01-01

155

Expressions of ecological identity across the life span of eight environmental exemplars  

NASA Astrophysics Data System (ADS)

While there is a substantial body of literature looking at various aspects of ecological identity and factors that influence it, there has been less work done on how an individual's ecological identity changes with time. Much of that work is limited to short segments of the life span (e.g. the impact of wilderness experiences). This dissertation attempts to address this perceived gap by investigating how the ecological identity of eight environmental exemplars changed during the course of his or her life. What has emerged from this qualitative grounded theory investigation of the lives and works of Charles Darwin, John Muir, Aldo Leopold, Marjory Stoneman Douglas, Hazel Wolf, Rachel Carson, James Lovelock and E.O. Wilson are five sequential expressions of ecological identity. These 'stages' serve as a framework to explain ecological identity as a developmental process, both fluid and continuous, rather than at) end product. The development of an ecological identity is traced, through the development of five cognitive foundations and their alignment with five emotional foundations that reflect a progression from a sensory interaction and a kinship bond with nature into a deep understanding of the interconnectedness of all aspects of the planet. The findings reveal the evolution of an ecological identity and suggest the importance of looking beyond content knowledge in the nurturing of ecological attitudes, values, and lifestyles.

Seydel, Jennifer

156

Everyday problem solving across the adult life span: solution diversity and efficacy  

PubMed Central

Everyday problem solving involves examining the solutions that individuals generate when faced with problems that take place in their everyday experiences. Problems can range from medication adherence and meal preparation to disagreeing with a physician over a recommended medical procedure or compromising with extended family members over where to host Thanksgiving dinner. Across the life span, research has demonstrated divergent patterns of change in performance based on the type of everyday problems used as well as based on the way that problem-solving efficacy is operationally defined. Advancing age is associated with worsening performance when tasks involve single-solution or fluency-based definitions of effectiveness. However, when efficacy is defined in terms of the diversity of strategies used, as well as by the social and emotional impact of solution choice on the individual, performance is remarkably stable and sometimes even improves in the latter half of life. This article discusses how both of these approaches to everyday problem solving inform research on the influence that aging has on everyday functioning. PMID:22023569

Mienaltowski, Andrew

2013-01-01

157

Monitoring Newly Synthesized Proteins over the Adult Life Span of Caenorhabditis elegans.  

PubMed

Little is known regarding how the synthesis and degradation of individual proteins change during the life of an organism. Such knowledge is vital to understanding the aging process. To fill this knowledge gap, we monitored newly synthesized proteins on a proteome scale in Caenorhabditis elegans over time during adulthood using a stable-isotope labeling by amino acids in cell culture (SILAC)-based label-chase approach. For most proteins, the rate of appearance of newly synthesized protein was high during the first 5 days of adulthood, slowed down between the fifth and the 11th days, and then increased again after the 11th day. However, the magnitude of appearance rate differed significantly from protein to protein. For example, the appearance of newly synthesized protein was fast for proteins involved in embryonic development, transcription regulation, and lipid binding/transport, with >70% of these proteins newly synthesized by day 5 of adulthood, whereas it was slow for proteins involved in cellular assembly and motility, such as actin and myosin, with <70% of these proteins newly synthesized even on day 16. The late-life increase of newly synthesized protein was especially high for ribosomal proteins and ATP synthases. We also investigated the effect of RNAi-mediated knockdown of the rpl-9 (ribosomal protein), atp-3 (ATP synthase), and ril-1 (RNAi-induced longevity-1) genes and found that inhibiting the expression of atp-3 and ril-1 beginning in late adulthood is still effective to extend the life span of C. elegans. PMID:25686393

Vukoti, Krishna; Yu, Xiaokun; Sheng, Quanhu; Saha, Sudipto; Feng, Zhaoyang; Hsu, Ao-Lin; Miyagi, Masaru

2015-03-01

158

Life-Span and Life-Space Literacy: Research and Policy in National and International Perspective. Occasional Paper OP92-1.  

ERIC Educational Resources Information Center

A more literate society cannot be created in the United States or elsewhere without a more comprehensive conceptual framework. This framework attempts explicitly to link children's acquisition of literacy with that of adults and assumes there is no single normative theory to literacy development. In a life-span and life-space approach, literacy…

Wagner, Daniel A.

159

Cognitive control and language across the life span: does labeling improve reactive control?  

PubMed

How does cognitive control change with age, and what are the processes underlying these changes? This question has been extensively studied using versions of the task-switching paradigm, which allow participants to actively prepare for the upcoming task (Kray, Eber, & Karbach, 2008). Little is known, however, about age-related changes in this ability across the life span when there is no opportunity to anticipate task goals. We examined the effect of 2 kinds of verbal self-instruction-labeling either the task goal or the relevant feature of the stimulus-on 2 components of cognitive control, goal setting and switching, in children, young adults, and older adults. All participants performed single-task blocks and mixed-task blocks (involving unpredictable switching between 2 tasks) in silent and labeling conditions. Participants categorized bidimensional stimuli either by picture or by color, depending on their spatial position in a 2-cell vertical grid. Response times revealed an inverted U shape in performance with age. These age differences were more pronounced for goal setting than for switching, thus generalizing results obtained in situations taping proactive control to this new context forcing reactive control. Further, differential age-related effects of verbalization were also obtained. Verbalizations were detrimental for young adults, beneficial for older adults, and had mixed effects in children. These differences are interpreted in terms of qualitative developmental changes in reactive goal-setting strategies. PMID:24491213

Lucenet, Joanna; Blaye, Agnès; Chevalier, Nicolas; Kray, Jutta

2014-05-01

160

Dietary Intake of Curcuma longa and Emblica officinalis Increases Life Span in Drosophila melanogaster  

PubMed Central

Intake of food and nutrition plays a major role in affecting aging process and longevity. However, the precise mechanisms underlying the ageing process are still unclear. To this respect, diet has been considered to be a determinant of ageing process. In order to better illustrate this, we used Drosophila melanogaster as a model and fed them orally with different concentrations of two commonly used Indian medicinal plant products, Curcuma longa (rhizome) and Emblica officinalis (fruit). The results revealed significant increase in life span of Drosophila flies on exposure to both the plant products, more efficiently by C. Longa than by E. officinalis. In order to understand whether the increase in lifespan was due to high-antioxidant properties of these medicinal plants, we performed enzymatic assays to assess the SOD and catalase activities in case of both treated and control Drosophila flies. Interestingly, the results support the free radical theory of aging as both these plant derivatives show high reactive oxygen species (ROS) scavenging activities. PMID:24967413

Rawal, Shilpa; Singh, Pavneet; Gupta, Ayush; Mohanty, Sujata

2014-01-01

161

Atrx deficiency induces telomere dysfunction, endocrine defects, and reduced life span  

PubMed Central

Human ATRX mutations are associated with cognitive deficits, developmental abnormalities, and cancer. We show that the Atrx-null embryonic mouse brain accumulates replicative damage at telomeres and pericentromeric heterochromatin, which is exacerbated by loss of p53 and linked to ATM activation. ATRX-deficient neuroprogenitors exhibited higher incidence of telomere fusions and increased sensitivity to replication stress–inducing drugs. Treatment of Atrx-null neuroprogenitors with the G-quadruplex (G4) ligand telomestatin increased DNA damage, indicating that ATRX likely aids in the replication of telomeric G4-DNA structures. Unexpectedly, mutant mice displayed reduced growth, shortened life span, lordokyphosis, cataracts, heart enlargement, and hypoglycemia, as well as reduction of mineral bone density, trabecular bone content, and subcutaneous fat. We show that a subset of these defects can be attributed to loss of ATRX in the embryonic anterior pituitary that resulted in low circulating levels of thyroxine and IGF-1. Our findings suggest that loss of ATRX increases DNA damage locally in the forebrain and anterior pituitary and causes tissue attrition and other systemic defects similar to those seen in aging. PMID:23563309

Watson, L. Ashley; Solomon, Lauren A.; Li, Jennifer Ruizhe; Jiang, Yan; Edwards, Matthew; Shin-ya, Kazuo; Beier, Frank; Bérubé, Nathalie G.

2013-01-01

162

A fasting-responsive signaling pathway that extends life span in C. elegans.  

PubMed

Intermittent fasting is one of the most effective dietary restriction regimens that extend life span in C. elegans and mammals. Fasting-stimulus responses are key to the longevity response; however, the mechanisms that sense and transduce the fasting stimulus remain largely unknown. Through a comprehensive transcriptome analysis in C. elegans, we find that along with the FOXO transcription factor DAF-16, AP-1 (JUN-1/FOS-1) plays a central role in fasting-induced transcriptional changes. KGB-1, one of the C. elegans JNKs, acts as an activator of AP-1 and is activated in response to fasting. KGB-1 and AP-1 are involved in intermittent fasting-induced longevity. Fasting-induced upregulation of the components of the SCF E3 ubiquitin ligase complex via AP-1 and DAF-16 enhances protein ubiquitination and reduces protein carbonylation. Our results thus identify a fasting-responsive KGB-1/AP-1 signaling pathway, which, together with DAF-16, causes transcriptional changes that mediate longevity, partly through regulating proteostasis. PMID:23352664

Uno, Masaharu; Honjoh, Sakiko; Matsuda, Mitsuhiro; Hoshikawa, Haruka; Kishimoto, Saya; Yamamoto, Tomohito; Ebisuya, Miki; Yamamoto, Takuya; Matsumoto, Kunihiro; Nishida, Eisuke

2013-01-31

163

The complex nature of family support across the life span: Implications for psychological well-being.  

PubMed

This study examines the complex role of family networks in shaping adult psychological well-being over time. We examine the unique and interactive longitudinal influences of family structure (i.e., composition and size) and negative family relationship quality on psychological well-being among young (ages 18-34), middle-aged (ages 35-49), and older adults (ages 50+). A sample of 881 adults (72% White; 26% Black) was drawn from the longitudinal Social Relations, Age, and Health Study. Structural equation modeling indicated that among young and middle-aged adults, increasing family negativity was associated with increases in depressive symptoms over time. In contrast, among older adults, lowered proportion of family in network and an increasing number of family members in the network (i.e., family size) were associated with decreases in depressive symptoms. These findings were moderated by family negativity. Among older adults with low family negativity, having a lower proportion of family and larger family size were associated with decreasing depressive symptoms, but there was no effect among those reporting high family negativity. Overall, these results contribute to an increased understanding of the complex, developmental nature of how family support influences well-being across the life span and highlights unique age differences. PMID:25602936

Fuller-Iglesias, Heather R; Webster, Noah J; Antonucci, Toni C

2015-03-01

164

Liver-Specific ?-Glutamyl Carboxylase-Deficient Mice Display Bleeding Diathesis and Short Life Span  

PubMed Central

Vitamin K is a fat-soluble vitamin that plays important roles in blood coagulation and bone metabolism. One of its functions is as a co-factor for ?-glutamyl carboxylase (Ggcx). Conventional knockout of Ggcx causes death shortly after birth in homozygous mice. We created Ggcx-floxed mice by inserting loxP sequences at the sites flanking exon 6 of Ggcx. By mating these mice with albumin-Cre mice, we generated Ggcx-deficient mice specifically in hepatocytes (Ggcx?liver/?liver mice). In contrast to conventional Ggcx knockout mice, Ggcx?liver/?liver mice had very low activity of Ggcx in the liver and survived several weeks after birth. Furthermore, compared with heterozygous mice (Ggcx+/?liver), Ggcx?liver/?liver mice had shorter life spans. Ggcx?liver/?liver mice displayed bleeding diathesis, which was accompanied by decreased activity of coagulation factors II and IX. Ggcx-floxed mice can prove useful in examining Ggcx functions in vivo. PMID:24520408

Azuma, Kotaro; Tsukui, Tohru; Ikeda, Kazuhiro; Shiba, Sachiko; Nakagawa, Kimie; Okano, Toshio; Urano, Tomohiko; Horie-Inoue, Kuniko; Ouchi, Yasuyoshi; Ikawa, Masahito; Inoue, Satoshi

2014-01-01

165

Bone marrow transplantation prolongs life span and ameliorates neurologic manifestations in Sandhoff disease mice.  

PubMed Central

The GM2 gangliosidoses are a group of severe, neurodegenerative conditions that include Tay-Sachs disease, Sandhoff disease, and the GM2 activator deficiency. Bone marrow transplantation (BMT) was examined as a potential treatment for these disorders using a Sandhoff disease mouse model. BMT extended the life span of these mice from approximately 4.5 mo to up to 8 mo and slowed their neurologic deterioration. BMT also corrected biochemical deficiencies in somatic tissues as indicated by decreased excretion of urinary oligosaccharides, and lower glycolipid storage and increased levels of beta-hexosaminidase activity in visceral organs. Even with neurologic improvement, neither clear reduction of brain glycolipid storage nor improvement in neuronal pathology could be detected, suggesting a complex pathogenic mechanism. Histological analysis revealed beta-hexosaminidase-positive cells in the central nervous system and visceral organs with a concomitant reduction of colloidal iron-positive macrophages. These results may be important for the design of treatment approaches for the GM2 gangliosidoses. PMID:9576752

Norflus, F; Tifft, C J; McDonald, M P; Goldstein, G; Crawley, J N; Hoffmann, A; Sandhoff, K; Suzuki, K; Proia, R L

1998-01-01

166

HIV1 dynamics in vivo: Virion clearance rate, infected cell life-span, and viral generation time  

Microsoft Academic Search

A new mathematical model was used to analyze a detailed set of human immunodeficiency virus-type 1 (HIV-1) viral load data collected from five infected individuals after the administration of a potent inhibitor of HIV-1 protease. Productively infected cells were estimated to have, on average, a life-span of 2.2 days (half-life tââ = 1.6 days), and plasma virions were estimated to

A. S. Perelson; A. U. Neumann; M. Markowitz; D. D. Ho; J. M. Leonard

1996-01-01

167

elf-reproduction is central to biological life for long-term sustainability and  

E-print Network

S elf-reproduction is central to biological life for long-term sustainability and evolutionary- reproduction have not been exploited in machine design1 . Here we create simple machines that act as autonomous modular robots and are capable of physical self- reproduction using a set of cubes. A physical system

Napp, Nils

168

Resource allocation in a social wasp: effects of breeding system and life cycle on reproductive decisions  

E-print Network

Resource allocation in a social wasp: effects of breeding system and life cycle on reproductive resources to reproduction. We investigated allocation decisions in the social wasp Vespula maculifrons to understand how social insects make reproductive choices. We first determined how annual colonies apportioned

Yi, Soojin

169

Modeling Life-Span Growth Curves of Cognition Using Longitudinal Data with Multiple Samples and Changing Scales of Measurement  

ERIC Educational Resources Information Center

The authors use multiple-sample longitudinal data from different test batteries to examine propositions about changes in constructs over the life span. The data come from 3 classic studies on intellectual abilities in which, in combination, 441 persons were repeatedly measured as many as 16 times over 70 years. They measured cognitive constructs…

McArdle, John J.; Grimm, Kevin J.; Hamagami, Fumiaki; Bowles, Ryan P.; Meredith, William

2009-01-01

170

ENDOCRINE PROFILES ASSOCIATED WITH LIFE SPAN OF INDUCED CORPORA LUTEA IN POSTPARTUM BEEF COWS 1'2  

Microsoft Academic Search

Two experiments were designed to examine whether hormonal profiles were related to luteal life span in pluriparous postpartum anestrous beef cows. Cows (Exp. 1, n = 34; Exp. 2, n = 23) received norgestomet (N) for 9 d or served as controls (C). Each cow received 1,000 IU human chorionic gonadotropin (hCG) 48 h after removal of N (d 0).

M. Garcia-Winder; E E. Lewis; D. R. Deaver; V. G. Smith; G. S. Lewis; E. K. Inskeep

2010-01-01

171

A Life-Span, Relational, Public Health Model of Self-Regulation: Impact on Individual and Community Health  

ERIC Educational Resources Information Center

In this chapter, the authors extend the ideas around the development of self-regulation and its impact on development by proposing a life-span, relational, public health model. They propose that the role of self-regulation should be understood across transitions from childhood to adulthood and through an individual and community perspective,…

Maniar, Swapnil; Zaff, Jonathan F.

2011-01-01

172

Changes in Acoustic Characteristics of the Voice across the Life Span: Measures from Individuals 4-93 Years of Age  

ERIC Educational Resources Information Center

Purpose: The purpose of the present investigation was to examine acoustic voice changes across the life span. Previous voice production investigations used small numbers of participants, had limited age ranges, and produced contradictory results. Method: Voice recordings were made from 192 male and female participants 4-93 years of age. Acoustic…

Stathopoulos, Elaine T.; Huber, Jessica E.; Sussman, Joan E.

2011-01-01

173

LINEAR ALLOMETRIC RELATIONSHIP BETWEEN TOTAL METABOLIC ENERGY PER LIFE SPAN AND BODY MASS OF TERRESTRIAL MAMMALS IN CAPTIVITY  

Microsoft Academic Search

Summary Atanasov, A.T., 2006. Linear allometric relationship between total metabolic energy per life span and body mass of terrestrial mammals in captivity. Bulg. J. Vet. Med. , 9, No 3, 159 ?174. The bioenergetic studies on animals have shown that basal metabolic rate P (kJ\\/d), is related to the body mass M (kg) of animals as expressed by the equation:

A. T. Atanasov

2006-01-01

174

Osteopenia is present at an early age and worsens across the life span in girls and women with Rett syndrome  

Technology Transfer Automated Retrieval System (TEKTRAN)

Girls and women with Rett syndrome (RTT) are at increased risk for osteopenia and skeletal fractures. Our objective was to characterize the natural history of bone mineralization in RTT girls and women across their life span and to identify genetic, nutritional, physical, hormonal, or inflammatory ...

175

Oxidative Stress Tolerance, Adenylate Cyclase, and Autophagy Are Key Players in the Chronological Life Span of Saccharomyces cerevisiae during Winemaking  

PubMed Central

Most grape juice fermentation takes place when yeast cells are in a nondividing state called the stationary phase. Under such circumstances, we aimed to identify the genetic determinants controlling longevity, known as the chronological life span. We identified commercial strains with both short (EC1118) and long (CSM) life spans in laboratory growth medium and compared them under diverse conditions. Strain CSM shows better tolerance to stresses, including oxidative stress, in the stationary phase. This is reflected during winemaking, when this strain has an increased maximum life span. Compared to EC1118, CSM overexpresses a mitochondrial rhodanese gene-like gene, RDL2, whose deletion leads to increased reactive oxygen species production at the end of fermentation and a correlative loss of viability at this point. EC1118 shows faster growth and higher expression of glycolytic genes, and this is related to greater PKA activity due to the upregulation of the adenylate cyclase gene. This phenotype has been linked to the presence of a ? element in its promoter, whose removal increases the life span. Finally, EC1118 exhibits a higher level of protein degradation by autophagy, which might help achieve fast growth at the expense of cellular structures and may be relevant for long-term survival under winemaking conditions. PMID:22327582

Orozco, Helena; Matallana, Emilia

2012-01-01

176

Self-Esteem Development across the Life Span: A Longitudinal Study with a Large Sample from Germany  

ERIC Educational Resources Information Center

The authors examined the development of self-esteem across the life span. Data came from a German longitudinal study with 3 assessments across 4 years of a sample of 2,509 individuals ages 14 to 89 years. The self-esteem measure used showed strong measurement invariance across assessments and birth cohorts. Latent growth curve analyses indicated…

Orth, Ulrich; Maes, Jürgen; Schmitt, Manfred

2015-01-01

177

The Genetic Architecture of Life Span and Mortality Rates: Gender and Species Differences in Inbreeding Load of Two Seed-Feeding Beetles  

PubMed Central

We examine the inbreeding load for adult life span and mortality rates of two seed beetle species, Callosobruchus maculatus and Stator limbatus. Inbreeding load differs substantially between males and females in both study populations of C. maculatus—life span of inbred females was 9–13% shorter than the life span of outbred females, whereas the life span of inbred males did not differ from the life span of outbred males. The effect of inbreeding on female life span was largely due to an increase in the slope of the mortality curve. In contrast, inbreeding had only a small effect on the life span of S. limbatus—life spans of inbred beetles were ?5% shorter than those of outbred beetles, and there was no difference in inbreeding load between the sexes. The inbreeding load for mean life span was ?0.4–0.6 lethal equivalents per haploid gamete for female C. maculatus and ?0.2–0.3 for both males and females of S. limbatus, all within the range of estimates commonly obtained for Drosophila. However, contrary to the predictions of mutation-accumulation models, inbreeding load for loci affecting mortality rates did not increase with age in either species, despite an effect of inbreeding on the initial rate of increase in mortality. This was because mortality rates decelerated with age and converged to a mortality plateau for both outbred and inbred beetles. PMID:16888331

Fox, Charles W.; Scheibly, Kristy L.; Wallin, William G.; Hitchcock, Lisa J.; Stillwell, R. Craig; Smith, Benjamin P.

2006-01-01

178

Cinnamomum cassia Bark in Two Herbal Formulas Increases Life Span in Caenorhabditis elegans via Insulin Signaling and Stress Response Pathways  

PubMed Central

Background Proving the efficacy and corresponding mode of action of herbal supplements is a difficult challenge for evidence-based herbal therapy. A major hurdle is the complexity of herbal preparations, many of which combine multiple herbs, particularly when the combination is assumed to be vitally important to the effectiveness of the herbal therapy. This issue may be addressed through the use of contemporary methodology and validated animal models. Methods and Principal Findings In this study, two commonly used traditional herbal formulas, Shi Quan Da Bu Tang (SQDB) and Huo Luo Xiao Ling Dan (HLXL) were evaluated using a survival assay and oxidative stress biomarkers in a well-established C. elegans model of aging. HLXL is an eleven herb formula modified from a top-selling traditional herbal formula for the treatment of arthritic joint pain. SQDB consists of ten herbs often used for fatigue and energy, particularly in the aged. We demonstrate here that SQDB significantly extend life span in a C. elegans model of aging. Among all individual herbs tested, two herbs Cinnamomum cassia bark (Chinese pharmaceutical name: Cinnamomi Cortex, CIN) and Panax ginseng root (Chinese pharmaceutical name: Ginseng Radix, GS) significantly extended life span in C. elegans. CIN in both SQDB and HLXL formula extended life span via modulation of multiple longevity assurance genes, including genes involved in insulin signaling and stress response pathways. All the life-span-extending herbs (SQDB, CIN and GS) also attenuated levels of H2O2 and enhanced small heat shock protein expression. Furthermore, the life span-extending herbs significantly delayed human amyloid beta (A?)-induced toxicity in transgenic C. elegans expressing human A?. Conclusion/Significance These results validate an invertebrate model for rapid, systematic evaluation of commonly used Chinese herbal formulations and may provide insight for designing future evidence-based herbal therapy(s). PMID:20179756

Yu, Young-Beob; Dosanjh, Laura; Lao, Lixing; Tan, Ming; Shim, Bum Sang; Luo, Yuan

2010-01-01

179

Sex differences in aging, life span and spontaneous tumorigenesis in 129/Sv mice neonatally exposed to metformin.  

PubMed

The perinatal (prenatal and early neonatal) period is a critical stage for hypothalamic programming of sexual differentiation as well as for the development of energy and metabolic homeostasis. We hypothesized that neonatal treatment with antidiabetic drug biguanide metformin would positively modify regulation of growth hormone - IGF-1 - insulin signaling pathway slowing down aging and improving cancer preventive patterns in rodents. To test this hypothesis male and female 129/Sv mice were s.c. injected with metformin (100 mg/kg) at the 3rd, 5th and 7th days after birth. Metformin-treated males consumed less food and water and their body weight was decreased as compared with control mice practically over their entire lifespan. There were no significant differences in age-related dynamics of food and water consumption in females and they were heavier than controls. The fraction of mice with regular estrous cycles decreased with age and demonstrated a tendency to decrease in the females neonatally treated with metformin. Neonatal exposure to metformin practically failed to change the extent of hormonal and metabolic parameters in blood serum of male and female mice. In males, neonatal metformin treatment significantly increased the mean life span (+20%, P < 0.05) and slightly increased the maximum life span (+3.5%). In females, the mean life span and median in metformin-treated groups were slightly decreased (-9.1% and -13.8% respectively, P > 0.05) in comparison to controls, whereas mean life span of last 10% survivors and maximum life span were the same as in controls. Almost half (45%) of control male mice and 71.8% male mice neonatally exposed to metformin survived up to 800 d of age, the same age was achieved by 54.3% of mice in control female group and 30% of metformin-treated females (P < 0.03). Thus, neonatal metformin exposure slows down aging and prolongs lifespan in male but not in female mice. PMID:25483062

Anisimov, Vladimir N; Popovich, Irina G; Zabezhinski, Mark A; Egormin, Peter A; Yurova, Maria N; Semenchenko, Anna V; Tyndyk, Margarita L; Panchenko, Andrey V; Trashkov, Alexandr P; Vasiliev, Andrey G; Khaitsev, Nikolai V

2015-01-01

180

Consilience and Life History Theory: From Genes to Brain to Reproductive Strategy  

ERIC Educational Resources Information Center

We describe an integrated theory of individual differences that traces the behavioral development of life history from genes to brain to reproductive strategy. We provide evidence that a single common factor, the K-Factor, underpins a variety of life-history parameters, including an assortment of sexual, reproductive, parental, familial, and…

Figueredo, Aurelio Jose; Vasquez, Geneva; Brumbach, Barbara H.; Schneider, Stephanie M. R.; Sefcek, Jon A.; Tal, Ilanit R.; Hill, Dawn; Wenner, Christopher J.; Jacobs, W. Jake

2006-01-01

181

Reproductive Life Events in the Population Living in the Vicinity of a Nuclear Waste Reprocessing Plant  

E-print Network

Reproductive Life Events in the Population Living in the Vicinity of a Nuclear Waste Reprocessing: There is concern about the health of populations living close to nuclear waste reprocessing plants. We conducted a comparative study on reproductive life events in the general population living near the nuclear waste

Paris-Sud XI, Université de

182

Attachment and the processing of social information across the life span: theory and evidence.  

PubMed

Researchers have used J. Bowlby's (1969/1982, 1973, 1980, 1988) attachment theory frequently as a basis for examining whether experiences in close personal relationships relate to the processing of social information across childhood, adolescence, and adulthood. We present an integrative life-span-encompassing theoretical model to explain the patterns of results that have emerged from these studies. The central proposition is that individuals who possess secure experience-based internal working models of attachment will process--in a relatively open manner--a broad range of positive and negative attachment-relevant social information. Moreover, secure individuals will draw on their positive attachment-related knowledge to process this information in a positively biased schematic way. In contrast, individuals who possess insecure internal working models of attachment will process attachment-relevant social information in one of two ways, depending on whether the information could cause the individual psychological pain. If processing the information is likely to lead to psychological pain, insecure individuals will defensively exclude this information from further processing. If, however, the information is unlikely to lead to psychological pain, then insecure individuals will process this information in a negatively biased schematic fashion that is congruent with their negative attachment-related experiences. In a comprehensive literature review, we describe studies that illustrate these patterns of attachment-related information processing from childhood to adulthood. This review focuses on studies that have examined specific components (e.g., attention and memory) and broader aspects (e.g., attributions) of social information processing. We also provide general conclusions and suggestions for future research. PMID:21219056

Dykas, Matthew J; Cassidy, Jude

2011-01-01

183

Biocultural Orchestration of Developmental Plasticity Across Levels: The Interplay of Biology and Culture in Shaping the Mind and Behavior Across the Life Span  

Microsoft Academic Search

The author reviews reemerging coconstructive conceptions of development and recent empirical findings of developmental plasticity at different levels spanning several fields of developmental and life sciences. A cross-level dynamic biocultural coconstructive framework is endorsed to understand cognitive and behavioral development across the life span. This framework integrates main conceptions of earlier views into a unifying frame, viewing the dynamics of

Shu-Chen Li

2003-01-01

184

Influence of early-life nutrition on mortality and reproductive success during a subsequent famine  

E-print Network

-life conditions, no study on humans has demonstrated the predicted fitness benefit under low later-life nutrition of metabolic diseases. developmental plasticity | silver spoon | human life-history | DoHAD Nutrition duringInfluence of early-life nutrition on mortality and reproductive success during a subsequent famine

Lummaa, Virpi

185

C. elegans ortholog of mammalian Ku70 interacts with insulin-like signaling to modulate stress resistance and life span  

PubMed Central

The mammalian Ku heterodimer has important roles in DNA double strand break repair, telomere maintenance, cell cycle checkpoint-arrest, tumor suppression, and cellular stress resistance. To investigate the evolutionarily conserved functions of Ku, we knocked down expression by RNA interference (RNAi) of Ku genes in C. elegans. We found that C. elegans Ku70 (CKU-70) is required for resistance to genotoxic stress, regulates cytotoxic stress responses, and influences aging. The latter effects are dependent on an IGF-1/insulin-like signaling pathway previously shown to affect life span. Reduction of CKU-70 activity amplifies the aging phenotype of long-lived insulin receptor daf-2 mutations in a daf-16-dependent manner. These observations support the view that organismal stress resistance determines life span and Ku70 modulates these effects. PMID:16099946

McColl, Gawain; Vantipalli, Maithili C.; Lithgow, Gordon J.

2006-01-01

186

Ageing in a eusocial insect: molecular and physiological characteristics of life span plasticity in the honey bee  

PubMed Central

Summary Commonly held views assume that ageing, or senescence, represents an inevitable, passive, and random decline in function that is strongly linked to chronological age. In recent years, genetic intervention of life span regulating pathways, for example, in Drosophila as well as case studies in non-classical animal models, have provided compelling evidence to challenge these views. Rather than comprehensively revisiting studies on the established genetic model systems of ageing, we here focus on an alternative model organism with a wild type (unselected genotype) characterized by a unique diversity in longevity – the honey bee. Honey bee (Apis mellifera) life span varies from a few weeks to more than 2 years. This plasticity is largely controlled by environmental factors. Thereby, although individuals are closely related genetically, distinct life histories can emerge as a function of social environmental change. Another remarkable feature of the honey bee is the occurrence of reverted behavioural ontogeny in the worker (female helper) caste. This behavioural peculiarity is associated with alterations in somatic maintenance functions that are indicative of reverted senescence. Thus, although intraspecific variation in organismal life span is not uncommon, the honey bee holds great promise for gaining insights into regulatory pathways that can shape the time-course of ageing by delaying, halting or even reversing processes of senescence. These aspects provide the setting of our review. We will highlight comparative findings from Drosophila melanogaster and Caenorhabditis elegans in particular, and focus on knowledge spanning from molecular- to behavioural-senescence to elucidate how the honey bee can contribute to novel insights into regulatory mechanisms that underlie plasticity and robustness or irreversibility in ageing. PMID:18728759

Münch, D.; Amdam, G. V.; Wolschin, F.

2008-01-01

187

Poly(ADP-Ribose) Polymerase Activity in Mononuclear Leukocytes of 13 Mammalian Species Correlates with Species-Specific Life Span  

Microsoft Academic Search

Poly(ADP-ribosyl)ation is a eukaryotic post-translational modification of proteins that is strongly induced by the presence of DNA strand breaks and plays a role in DNA repair and the recovery of cells from DNA damage. We compared poly(ADP-ribose) polymerase (PARP; EC 2.4.2.30) activities in Percoll gradient-purified, permeabilized mononuclear leukocytes from mammalian species of different maximal life span. Saturating concentrations of a

Karlheinz Grube; Alexander Burkle

1992-01-01

188

Poly(ADP-ribose) polymerase activity in mononuclear leukocytes of 13 mammalian species correlates with species-specific life span.  

PubMed Central

Poly(ADP-ribosyl)ation is a eukaryotic posttranslational modification of proteins that is strongly induced by the presence of DNA strand breaks and plays a role in DNA repair and the recovery of cells from DNA damage. We compared poly(ADP-ribose) polymerase (PARP; EC 2.4.2.30) activities in Percoll gradient-purified, permeabilized mononuclear leukocytes from mammalian species of different maximal life span. Saturating concentrations of a double-stranded octameric oligonucleotide were applied to provide a direct and maximal stimulation of PARP. Our results on 132 individuals from 13 different species yield a strong positive correlation between PARP activity and life span (r = 0.84; P << 0.001), with human cells displaying approximately 5 times the activity of rat cells. Intraspecies comparisons with both rat and human cells from donors of all age groups revealed some decline of PARP activity with advancing age, but it was only weakly correlated. No significant polymer degradation was detectable under our assay conditions, ruling out any interference by poly(ADP-ribose) glycohydrolase activity. By Western blot analysis of mononuclear leukocytes from 11 species, using a crossreactive antiserum directed against the extremely well-conserved NAD-binding domain, no correlation between the amount of PARP protein and the species' life spans was found, suggesting a greater specific enzyme activity in longer-lived species. We propose that a higher poly(ADP-ribosyl)ation capacity in cells from long-lived species might contribute to the efficient maintenance of genome integrity and stability over their longer life span. Images PMID:1465394

Grube, K; Bürkle, A

1992-01-01

189

Physical activity : its implication on attention span and quality of life in children with Autism Spectrum Disorder  

Microsoft Academic Search

The current study was designed to partially extend previous research (Nicholson, Kehle, Bray, & Heest, 2011; Rosenthal-Malek & Mitchell, 1997) by examining the effects of physical activity on the 1) attention span and 2) health-related quality of life (HRQoL) of autism spectrum disorder (ASD) children in Singapore. Male participants (N = 12) aged 2-6 years, diagnosed with ASD were randomly

Wei Zhong Beron Tan

2011-01-01

190

Life span of patients with Eisenmenger syndrome is not superior to that of patients with other causes of pulmonary hypertension  

PubMed Central

Background Patients with Eisenmenger syndrome (ES) carry a better prognosis from diagnosis than patients with other causes of pulmonary hypertension (PH), but their life span has not yet been clarified. Aims To clarify both survival from diagnosis and life span in ES, and in closed shunt with pulmonary arterial hypertension (PAH), as compared with other causes of PH. Methods Data on all adult patients with PH attending our centre over the past decade was collected. Outcome was defined as death or transplantation. Results We studied 149 patients, including 30 (20%) patients with ES and 12 (8%) patients with closed shunt with PAH. Median age at diagnosis was lower for patients with ES and closed-shunt with PAH compared to patients with other causes of PH (P<0.001 and P=0.008 respectively). Median follow-up was 4.25 years. Survival from diagnosis was longer in ES compared to other causes of PH (logrank; P=0.02) and similar between closed-shunt with PAH and other causes of PH (logrank; P=0.3). Survival rates at 3, 6 and 9 years from diagnosis were: 73%, 50% and 47% for ES, 75%, 25% and 0% for closed-shunt with PAH, 65%, 23% and 9% for other causes of PH. Life span was similar in those three groups (logrank; P=0.2 and P=0.7, respectively). Conclusions Life span is similar in patients with ES, with a closed-shunt associated with PAH, and in patients with other causes of PH. PMID:25414820

Renard, Sébastien; Mancini, Julien; Hubert, Sandrine; Habib, Gilbert; Fraisse, Alain

2014-01-01

191

Lack of methionine sulfoxide reductase A in mice increases sensitivity to oxidative stress but does not diminish life span  

PubMed Central

Methionine sulfoxide reductase A (MsrA) repairs oxidized methionine residues within proteins and may also function as a general antioxidant. Previous reports have suggested that modulation of MsrA in mice and mammalian cell culture can affect the accumulation of oxidized proteins and may regulate resistance to oxidative stress. Thus, under the oxidative stress theory of aging, these results would predict that MsrA regulates the aging process in mammals. We show here that MsrA?/? mice are more susceptible to oxidative stress induced by paraquat. Skin-derived fibroblasts do not express MsrA, but fibroblasts cultured from MsrA?/? mice were, nevertheless, also more susceptible to killing by various oxidative stresses. In contrast to previous reports, we find no evidence for neuromuscular dysfunction in MsrA?/? mice in either young adult or in older animals. Most important, we found no difference between MsrA?/? and control mice in either their median or maximum life span. Thus, our results show that MsrA regulates sensitivity to oxidative stress in mice but has no effect on aging, as determined by life span.—Salmon, A. B., Pérez, V. I., Bokov, A., Jernigan, A., Kim, G., Zhao, H., Levine, R. L., Richardson, A. Lack of methionine sulfoxide reductase A in mice increases sensitivity to oxidative stress but does not diminish life span. PMID:19487311

Salmon, Adam B.; Pérez, Viviana I.; Bokov, Alex; Jernigan, Amanda; Kim, Geumsoo; Zhao, Hang; Levine, Rodney L.; Richardson, Arlan

2009-01-01

192

The extended life span of Drosophila melanogaster eye-color (white and vermilion) mutants with impaired formation of kynurenine.  

PubMed

Animal and human studies suggest that aging is associated with increased formation of kynurenine (KYN) from tryptophan (TRY). The rate-limiting factors of TRY-KYN metabolism are transmembrane transport of TRY, and activity of enzyme, TRY 2,3-dioxygenase (TDO2). Eye-color mutants, white (w1118) (impaired TRY transport) and vermilion (v48a and v2) (deficient TDO activity), were compared with wild-type Oregon-R (Ore-R) strain of Drosophila melanogaster. Female 1-day-old adult flies maintained on a standard medium, and acclimatized to 12-h light:12-h dark cycle were collected, and then regularly transferred to fresh medium every 3-4 days. The number of dead flies was recorded at the time of transfer. Forty flies were studied in each experimental group. The life span of w1118 (mean = 45.5 days), and v48a (mean = 47.6 days) and v2 (mean = 43.8 days), were significantly longer than of wild-type Ore-R flies (27.1 days) (p < 0.001, Logrank test). There were no differences in life span between w1118 and v48a and v2 mutants. Present results suggest that prolongation of life span may be associated with slow rate of KYN formation from TRY. PMID:19941150

Oxenkrug, Gregory F

2010-01-01

193

Self-esteem development across the life span: A longitudinal study with a large sample from Germany.  

PubMed

The authors examined the development of self-esteem across the life span. Data came from a German longitudinal study with 3 assessments across 4 years of a sample of 2,509 individuals ages 14 to 89 years. The self-esteem measure used showed strong measurement invariance across assessments and birth cohorts. Latent growth curve analyses indicated that self-esteem follows a quadratic trajectory across the life span, increasing during adolescence, young adulthood, and middle adulthood, reaching a peak at age 60 years, and then declining in old age. No cohort effects on average levels of self-esteem or on the shape of the trajectory were found. Moreover, the trajectory did not differ across gender, level of education, or for individuals who had lived continuously in West versus East Germany (i.e., the 2 parts of Germany that had been separate states from 1949 to 1990). However, the results suggested that employment status, household income, and satisfaction in the domains of work, relationships, and health contribute to a more positive life span trajectory of self-esteem. The findings have significant implications, because they call attention to developmental stages in which individuals may be vulnerable because of low self-esteem (such as adolescence and old age) and to factors that predict successful versus problematic developmental trajectories. (PsycINFO Database Record (c) 2015 APA, all rights reserved). PMID:25485608

Orth, Ulrich; Maes, Jürgen; Schmitt, Manfred

2015-02-01

194

Delayed accumulation of intestinal coliform bacteria enhances life span and stress resistance in Caenorhabditis elegans fed respiratory deficient E. coli  

PubMed Central

Background Studies with the nematode model Caenorhabditis elegans have identified conserved biochemical pathways that act to modulate life span. Life span can also be influenced by the composition of the intestinal microbiome, and C. elegans life span can be dramatically influenced by its diet of Escherichia coli. Although C. elegans is typically fed the standard OP50 strain of E. coli, nematodes fed E. coli strains rendered respiratory deficient, either due to a lack coenzyme Q or the absence of ATP synthase, show significant life span extension. Here we explore the mechanisms accounting for the enhanced nematode life span in response to these diets. Results The intestinal load of E. coli was monitored by determination of worm-associated colony forming units (cfu/worm or coliform counts) as a function of age. The presence of GFP-expressing E. coli in the worm intestine was also monitored by fluorescence microscopy. Worms fed the standard OP50 E. coli strain have high cfu and GFP-labeled bacteria in their guts at the L4 larval stage, and show saturated coliform counts by day five of adulthood. In contrast, nematodes fed diets of respiratory deficient E. coli lacking coenzyme Q lived significantly longer and failed to accumulate bacteria within the lumen at early ages. Animals fed bacteria deficient in complex V showed intermediate coliform numbers and were not quite as long-lived. The results indicate that respiratory deficient Q-less E. coli are effectively degraded in the early adult worm, either at the pharynx or within the intestine, and do not accumulate in the intestinal tract until day ten of adulthood. Conclusions The findings of this study suggest that the nematodes fed the respiratory deficient E. coli diet live longer because the delay in bacterial colonization of the gut subjects the worms to less stress compared to worms fed the OP50 E. coli diet. This work suggests that bacterial respiration can act as a virulence factor, influencing the ability of bacteria to colonize and subsequently harm the animal host. Respiratory deficient bacteria may pose a useful model for probing probiotic relationships within the gut microbiome in higher organisms. PMID:23256533

2012-01-01

195

Plant Reproduction. Plant Life in Action[TM]. Schlessinger Science Library. [Videotape].  

ERIC Educational Resources Information Center

Plants are vital to all other life on this planet - without them, there would be no food, shelter or oxygen. Luckily, over millions of years plants have developed many different features in order to survive and reproduce. In Plant Reproduction, students will discover that primitive mosses and algae are dependent upon water for their reproduction

2000

196

Variability in Reproductive Success Viewed From a Life-History Perspective in Baboons  

E-print Network

Variability in Reproductive Success Viewed From a Life-History Perspective in Baboons JEANNE- tribute to within-population variance in reproductive success for savannah baboons. We also discuss the extent to which savannah baboons, with their highly flexible and adaptable behavior, change

Alberts, Susan C

197

Female temperament, tumor development and life span: relation to glucocorticoid and tumor necrosis factor alpha levels in rats.  

PubMed

Behavioral characteristics closely associated with specific physiological profiles present an important area of research in understanding health disparities. In particular, glucocorticoid overproduction may be an important factor moderating disease progression; natural variance in production of this steroid has been proposed as one mechanism underlying individual differences in health and disease. In the current paper, we examined immune parameters in female rats of two different behavioral types previously shown to have differential glucocorticoid production and life spans. We categorized young female rats according to their behavioral response to novelty (high- or low-locomotion), and compared their glucocorticoid production, adrenal size, thymus size, tumor necrosis factor-alpha (TNF-alpha) production, tumor development and life span. As expected, high-locomotion females produced more glucocorticoids and had larger adrenal glands during young adulthood than did low-locomotion females. High-locomotion females had significantly smaller thymuses and reduced TNF-alpha levels compared to low-locomotion, suggesting altered immune function in young adulthood. Finally, high-locomotion females had shorter life spans than did low-locomotion females, and this was particularly true in females that developed pituitary tumors, but not in those that developed mammary tumors. These results, along with other published findings, suggest that high-locomotion rodent females experience life-long elevations in glucocorticoid responses to novelty, and that these elevated levels may be comparable to chronic stress. This naturally occurring endocrine profile may influence immune responses which in turn could affect disease susceptibility. Variance in immune function across personality types may be partially moderated by natural variance in glucocorticoid production. PMID:18155400

Cavigelli, Sonia A; Bennett, Jeanette M; Michael, Kerry C; Klein, Laura Cousino

2008-07-01

198

COPEPOD REPRODUCTIVE STRATEGIES: LIFE-HISTORY THEORY, PHYLOGENETIC PATTERN AND INVASION OF INLAND WATERS. (R824771)  

EPA Science Inventory

Abstract Life-history theory predicts that different reproductive strategies should evolve in environments that differ in resource availability, mortality, seasonality, and in spatial or temporal variation. Within a population, the predicted optimal strategy is driven ...

199

C. elegans 14-3-3 proteins regulate life span and interact with SIR2.1 and DAF-16\\/FOXO  

Microsoft Academic Search

14-3-3 proteins are evolutionarily conserved and ubiquitous proteins that function in a wide variety of biological processes. Here we define a new role for C. elegans 14-3-3 proteins in life span regulation. We identify two C. elegans 14-3-3 proteins as interacting proteins of a major life span regulator, the C. elegans SIR2 ortholog, SIR-2.1. Similar to sir-2.1, we find that

Yamei Wang; Seung Wook Oh; Bart Deplancke; Jianyuan Luo; Albertha J. M. Walhout; Heidi A. Tissenbaum

2006-01-01

200

Comparison of Building Energy Efficiency and Life Span for Different Envelopes  

E-print Network

Unsuitable building energy saving technology will result in plenty building trash and waste buildings. In China, the life of many buildings is less than 50 years because of improper building heat preservation envelopes. It is found that irrational...

Li, Z.; Li, D.; Li, L.; Zhang, G.; Liu, J.

2006-01-01

201

Telomerase-mediated life-span extension of human primary fibroblasts by human artificial chromosome (HAC) vector  

SciTech Connect

Telomerase-mediated life-span extension enables the expansion of normal cells without malignant transformation, and thus has been thought to be useful in cell therapies. Currently, integrating vectors including the retrovirus are used for human telomerase reverse transcriptase (hTERT)-mediated expansion of normal cells; however, the use of these vectors potentially causes unexpected insertional mutagenesis and/or activation of oncogenes. Here, we established normal human fibroblast (hPF) clones retaining non-integrating human artificial chromosome (HAC) vectors harboring the hTERT expression cassette. In hTERT-HAC/hPF clones, we observed the telomerase activity and the suppression of senescent-associated SA-{beta}-galactosidase activity. Furthermore, the hTERT-HAC/hPF clones continued growing beyond 120 days after cloning, whereas the hPF clones retaining the silent hTERT-HAC senesced within 70 days. Thus, hTERT-HAC-mediated episomal expression of hTERT allows the extension of the life-span of human primary cells, implying that gene delivery by non-integrating HAC vectors can be used to control cellular proliferative capacity of primary cultured cells.

Shitara, Shingo [Department of Biomedical Science, Institute of Regenerative Medicine and Biofunction, Graduate School of Medical Sciences, Tottori University, 86 Nishimachi, Yonago, Tottori 683-8503 (Japan); Kakeda, Minoru; Nagata, Keiko [Discovery Research Laboratories, Kirin Pharma Co., Ltd., 3 Miyahara-cho, Takasaki-shi, Gunma 370-1295 (Japan); Hiratsuka, Masaharu [Department of Biomedical Science, Institute of Regenerative Medicine and Biofunction, Graduate School of Medical Sciences, Tottori University, 86 Nishimachi, Yonago, Tottori 683-8503 (Japan); Sano, Akiko; Osawa, Kanako; Okazaki, Akiyo [Discovery Research Laboratories, Kirin Pharma Co., Ltd., 3 Miyahara-cho, Takasaki-shi, Gunma 370-1295 (Japan); Katoh, Motonobu; Kazuki, Yasuhiro; Oshimura, Mitsuo [Department of Biomedical Science, Institute of Regenerative Medicine and Biofunction, Graduate School of Medical Sciences, Tottori University, 86 Nishimachi, Yonago, Tottori 683-8503 (Japan); Tomizuka, Kazuma [Department of Biomedical Science, Institute of Regenerative Medicine and Biofunction, Graduate School of Medical Sciences, Tottori University, 86 Nishimachi, Yonago, Tottori 683-8503 (Japan); Discovery Research Laboratories, Kirin Pharma Co., Ltd., 3 Miyahara-cho, Takasaki-shi, Gunma 370-1295 (Japan)], E-mail: ktomizuka@kirin.co.jp

2008-05-09

202

Genetic Structures of Population Cohorts Change with Increasing Age: Implications for Genetic Analyses of Human aging and Life Span  

PubMed Central

Background Correcting for the potential effects of population stratification is an important issue in genome wide association studies (GWAS) of complex traits. Principal component analysis (PCA) of the genetic structure of the population under study with subsequent incorporation of the first several principal components (PCs) in the GWAS regression model is often used for this purpose. Problem For longevity related traits such a correction may negatively affect the accuracy of genetic analyses. This is because PCs may capture genetic structure induced by mortality selection processes in genetically heterogeneous populations. Data and Methods We used the Framingham Heart Study data on life span and on individual genetic background to construct two sets of PCs. One was constructed to separate population stratification due to differences in ancestry from that induced by mortality selection. The other was constructed using genetic data on individuals of different ages without attempting to separate the ancestry effects from the mortality selection effects. The GWASs of human life span were performed using the first 20 PCs from each of the selected sets to control for possible population stratification. Results The results indicated that the GWAS that used the PC set separating population stratification induced by mortality selection from differences in ancestry produced stronger genetic signals than the GWAS that used PCs without such separation. Conclusion The quality of genetic estimates in GWAS can be improved when changes in genetic structure caused by mortality selection are taken into account in controlling for possible effects of population stratification.

Yashin, Anatoliy I.; Wu, Deqing; Arbeev, Konstantin G.; Arbeeva, Liubov S.; Akushevich, Igor; Kulminski, Alexander; Culminskaya, Irina; Stallard, Eric; Ukraintseva, Svetlana V.

2015-01-01

203

Bmi-1 extends the life span of normal human oral keratinocytes by inhibiting the TGF-{beta} signaling  

SciTech Connect

We previously demonstrated that Bmi-1 extended the in vitro life span of normal human oral keratinocytes (NHOK). We now report that the prolonged life span of NHOK by Bmi-1 is, in part, due to inhibition of the TGF-{beta} signaling pathway. Serial subculture of NHOK resulted in replicative senescence and terminal differentiation and activation of TGF-{beta} signaling pathway. This was accompanied with enhanced intracellular and secreted TGF-{beta}1 levels, phosphorylation of Smad2/3, and increased expression of p15{sup INK4B} and p57{sup KIP2}. An ectopic expression of Bmi-1 in NHOK (HOK/Bmi-1) decreased the level of intracellular and secreted TGF-{beta}1 induced dephosphorylation of Smad2/3, and diminished the level of p15{sup INK4B} and p57{sup KIP2}. Moreover, Bmi-1 expression led to the inhibition of TGF-{beta}-responsive promoter activity in a dose-specific manner. Knockdown of Bmi-1 in rapidly proliferating HOK/Bmi-1 and cancer cells increased the level of phosphorylated Smad2/3, p15{sup INK4B}, and p57{sup KIP2}. In addition, an exposure of senescent NHOK to TGF-{beta} receptor I kinase inhibitor or anti-TGF-{beta} antibody resulted in enhanced replicative potential of cells. Taken together, these data suggest that Bmi-1 suppresses senescence of cells by inhibiting the TGF-{beta} signaling pathway in NHOK.

Kim, Reuben H., E-mail: rkim@dentistry.ucla.edu [UCLA School of Dentistry, Los Angeles, CA 90095 (United States); UCLA Dental Research Institute, Los Angeles, CA 90095 (United States); UCLA Jonsson Comprehensive Cancer Center, Los Angeles, CA 90095 (United States); Lieberman, Mark B.; Lee, Rachel [UCLA School of Dentistry, Los Angeles, CA 90095 (United States)] [UCLA School of Dentistry, Los Angeles, CA 90095 (United States); Shin, Ki-Hyuk [UCLA School of Dentistry, Los Angeles, CA 90095 (United States) [UCLA School of Dentistry, Los Angeles, CA 90095 (United States); UCLA Dental Research Institute, Los Angeles, CA 90095 (United States); UCLA Jonsson Comprehensive Cancer Center, Los Angeles, CA 90095 (United States); Mehrazarin, Shebli; Oh, Ju-Eun [UCLA School of Dentistry, Los Angeles, CA 90095 (United States)] [UCLA School of Dentistry, Los Angeles, CA 90095 (United States); Park, No-Hee [UCLA School of Dentistry, Los Angeles, CA 90095 (United States) [UCLA School of Dentistry, Los Angeles, CA 90095 (United States); UCLA Dental Research Institute, Los Angeles, CA 90095 (United States); UCLA Jonsson Comprehensive Cancer Center, Los Angeles, CA 90095 (United States); David Geffen School of Medicine at UCLA, Los Angeles, CA 90095 (United States); Kang, Mo K., E-mail: mkang@dentistry.ucla.edu [UCLA School of Dentistry, Los Angeles, CA 90095 (United States); UCLA Dental Research Institute, Los Angeles, CA 90095 (United States); UCLA Jonsson Comprehensive Cancer Center, Los Angeles, CA 90095 (United States)

2010-10-01

204

Ethical concerns in the community about technologies to extend human life span.  

PubMed

Debates about the ethical and social implications of research that aims to extend human longevity by intervening in the ageing process have paid little attention to the attitudes of members of the general public. In the absence of empirical evidence, conflicting assumptions have been made about likely public attitudes towards life-extension. In light of recent calls for greater public involvement in such discussions, this target article presents findings from focus groups and individual interviews which investigated whether members of the general public identify ethical issues surrounding life-extension, and if so, what these ethical issues are? In this study, while some participants were concerned primarily with the likely personal consequences of life-extension, for others the question of whether or not to pursue interventions to extend longevity, and how they should be implemented, clearly raised important ethical issues, many of which have been prominent in debates among bioethicists. PMID:20013509

Partridge, Brad; Underwood, Mair; Lucke, Jayne; Bartlett, Helen; Hall, Wayne

2009-12-01

205

Human evolution, life history theory, and the end of biological reproduction.  

PubMed

Throughout primate history there have been three major life history transitions towards increasingly delayed sexual maturation and biological reproduction, as well as towards extended life expectancy. Monkeys reproduce later and live longer than do prosimians, apes reproduce later and live longer than do monkeys, and humans reproduce later and live longer than do apes. These life history transitions are connected to increased encephalization. During the last life history transition from apes to humans, increased encephalization co-evolved with increased dependence on cultural knowledge for energy acquisition. This led to a dramatic pressure for more energy investment in growth over current biological reproduction. Since the industrial revolution socioeconomic development has led to even more energy being devoted to growth over current biological reproduction. I propose that this is the beginning of an ongoing fourth major primate life history transition towards completely delayed biological reproduction and an extension of the evolved human life expectancy. I argue that the only fundamental difference between this primate life history transition and previous life history transitions is that this transition is being driven solely by cultural evolution, which may suggest some deeper evolutionary transition away from biological evolution is already in the process of occurring. PMID:24852016

Last, Cadell

2014-01-01

206

Choice of Friends over the Life Span: Developmental and Environmental Influences. Report No. 345.  

ERIC Educational Resources Information Center

Previous research on friendship selection has failed to focus on how the selection process changes with age or in differently organized environments. This review of the literature takes a life-course perspective on the selection of friends, charting research results on three aspects of the selection process: (1) the number of friends and their…

Epstein, Joyce L.

207

Ethical Concerns in the Community About Technologies to Extend Human Life Span  

Microsoft Academic Search

Debates about the ethical and social implications of research that aims to extend human longevity by intervening in the ageing process have paid little attention to the attitudes of members of the general public. In the absence of empirical evidence, conflicting assumptions have been made about likely public attitudes towards life-extension. In light of recent calls for greater public involvement

Brad Partridge; Mair Underwood; Jayne Lucke; Helen Bartlett; Wayne Hall

2009-01-01

208

A Multilevel Model Analysis of Expertise in Chess Across the Life Span  

Microsoft Academic Search

The authors examined longitudinal change in chess skill using a multilevel model analysis of a large database of active, elite chess players (N = 5,011). Parameters estimated from quadratic growth curves indicated that the age of peak performance occurs later in life than originally proposed and that this peak is independent of initial skill level. The findings are also consistent

Roy W. Roring; Neil Charness

2007-01-01

209

Life-long spontaneous exercise does not prolong lifespan but improves health span in mice  

PubMed Central

Background Life expectancy at birth in the first world has increased from 35 years at the beginning of the 20th century to more than 80 years now. The increase in life expectancy has resulted in an increase in age-related diseases and larger numbers of frail and dependent people. The aim of our study was to determine whether life-long spontaneous aerobic exercise affects lifespan and healthspan in mice. Results Male C57Bl/6J mice, individually caged, were randomly assigned to one of two groups: sedentary (n = 72) or spontaneous wheel-runners (n = 72). We evaluated longevity and several health parameters including grip strength, motor coordination, exercise capacity (VO2max) and skeletal muscle mitochondrial biogenesis. We also measured the cortical levels of the brain-derived neurotrophic factor (BDNF), a neurotrophin associated with brain plasticity. In addition, we measured systemic oxidative stress (malondialdehyde and protein carbonyl plasma levels) and the expression and activity of two genes involved in antioxidant defense in the liver (that is, glutathione peroxidase (GPx) and manganese superoxide dismutase (Mn-SOD)). Genes that encode antioxidant enzymes are considered longevity genes because their over-expression may modulate lifespan. Aging was associated with an increase in oxidative stress biomarkers and in the activity of the antioxidant enzymes, GPx and Mn-SOD, in the liver in mice. Life-long spontaneous exercise did not prolong longevity but prevented several signs of frailty (that is, decrease in strength, endurance and motor coordination). This improvement was accompanied by a significant increase in the mitochondrial biogenesis in skeletal muscle and in the cortical BDNF levels. Conclusion Life-long spontaneous exercise does not prolong lifespan but improves healthspan in mice. Exercise is an intervention that delays age-associated frailty, enhances function and can be translated into the clinic. PMID:24472376

2013-01-01

210

Protein:carbohydrate ratios explain life span patterns found in Queensland fruit fly on diets varying in yeast:sugar ratios.  

PubMed

Dietary restriction extends life span across a vast diversity of taxa, but significant challenges remain in elucidating the underlying mechanisms. Distinguishing between caloric and nutrient effects is an essential step. Recent studies with Drosophila and tephritid fruit flies have reported increased life span as dietary yeast-to-sugar ratios decreased and these effects have been attributed to changes in protein-to-carbohydrate (P:C) ratios of the diets rather than calories. However, yeast is a complex mix of macronutrients and micronutrients, and hence changes in yeast content of the diet necessarily alters other nutrients in lockstep. To explicitly test whether studies using yeast are justified in attributing results to diet protein content rather than correlated nutrients, we developed a chemically defined diet allowing manipulation of just the ratio of protein (free amino acids) to carbohydrate (sucrose) levels of diets while holding other nutrients constant. Mated, female Queensland fruit flies (Q-flies) were fed 1 of 18 diets varying in P:C ratios and diet concentration. Diet consumption, egg production, and life span were recorded for each fly. In close concordance with recent studies using yeast diets, flies had increased life span as P:C ratios decreased, and caloric restriction did not extend life span. Similarly, egg production was maximized on high P:C ratios, but lifetime egg production was maximized on intermediate P:C ratios, indicating a life history trade-off between life span and egg production rate. Finally, Q-flies adjusted their diet intake in response to P:C ratios and diet concentration. Our results substantiate recent claims that P:C ratios significantly modulate life span in flies. PMID:21904823

Fanson, Benjamin G; Taylor, Phillip W

2012-12-01

211

Life Beyond the Eating Disorder: Education, Relationships, and Reproduction  

PubMed Central

Objective We investigated sociodemographic characteristics in women with and without lifetime eating disorders. Method Participants were from a multi-site international study of eating disorders (N = 2096). Education level, relationship status, and reproductive status were examined across eating disorder subtypes and compared with a healthy control group. Results Overall, women with eating disorders were less educated than controls, and duration of illness and age of onset were associated with educational attainment. Menstrual status was associated with both relationship and reproductive status, but eating disorder subtypes did not differ significantly from each other or from healthy controls on these dimensions. Conclusion Differences in educational attainment, relationships, and reproduction do exist in individuals with eating disorders and are differentially associated with various eating disorder symptoms and characteristics. These data could assist with educating patients and family members about long-term consequences of eating disorders. PMID:20143323

Maxwell, Millie; Thornton, Laura M.; Root, Tammy L.; Pinheiro, Andrea Poyastro; Strober, Michael; Brandt, Harry; Crawford, Steve; Crow, Scott; Fichter, Manfred M.; Halmi, Katherine A.; Johnson, Craig; Kaplan, Allan S.; Keel, Pamela; Klump, Kelly L.; LaVia, Maria; Mitchell, James E.; Plotnicov, Kathy; Rotondo, Alessandro; Woodside, D. Blake; Berrettini, Wade H.; Kaye, Walter H.; Bulik, Cynthia M.

2010-01-01

212

Differential effects of the extracellular microenvironment on human embryonic stem cell differentiation into keratinocytes and their subsequent replicative life span.  

PubMed

Culture microenvironment plays a critical role in the propagation and differentiation of human embryonic stem cells (hESCs) and their differentiated progenies. Although high efficiency of hESC differentiation to keratinocytes (hESC-Kert) has been achieved, little is known regarding the effects of early culture microenvironment and pertinent extracellular matrix (ECM) interactions during epidermal commitment on subsequent proliferative capacity of hESC-Kert. The aim of this study is to evaluate the effects of the different ECM microenvironments during hESC differentiation on subsequent replicative life span of hESC-Kert. In doing so, H1-hESCs were differentiated to keratinocytes (H1-Kert) in two differentiation systems. The first system employed autologous fibroblast feeder support, in which keratinocytes (H1-Kert(ACC)) were derived by coculture of hESCs with hESC-derived fibroblasts (H1-ebFs). The second system employed a novel decellularized matrix from H1-ebFs to create a dermoepidermal junction-like (DEJ) matrix. H1-Kert(AFF) were derived by differentiation of hESCs on the feeder-free system employing the DEJ matrix. Our study indicated that the feeder-free system with the use of DEJ matrix was more efficient in differentiation of hESCs toward epidermal progenitors. However, the feeder-free system was not sufficient to support the subsequent replicative capacity of differentiated keratinocytes. Of note, H1-Kert(AFF) showed limited replicative capacity with reduced telomere length and early cellular senescence. We further showed that the lack of cell-cell interactions during epidermal commitment led to heightened production of TGF-?1 by hESC-Kert during extended culture, which in turn was responsible for resulting in the limited replicative life span with cellular senescence of hESC-Kert derived under the feeder-free culture system. This study highlights for the first time the importance of the culture microenvironment and cell-ECM interactions during differentiation of hESCs on subsequent replicative life span and cellular senescence of the differentiated keratinocytes, with implications for use of these cells for applications in tissue engineering and regenerative medicine. PMID:25693643

Movahednia, Mohammad Mehdi; Kidwai, Fahad Karim; Zou, Yu; Tong, Huei Jinn; Liu, Xiaochen; Islam, Intekhab; Toh, Wei Seong; Raghunath, Michael; Cao, Tong

2015-04-01

213

Reproductive isolation following reintroduction of Chinook salmon with alternative life histories  

Microsoft Academic Search

We evaluated reproductive isolation of Chinook salmon (Oncorhynchus tshawytscha) life history types that have been reintroduced to northern Idaho, USA. Analysis of 1003 samples at six microsatellite loci\\u000a revealed strong reproductive isolation between ocean- and stream-type Chinook salmon (fall and summer spawn timing, respectively)\\u000a within the Clearwater River sub-basin (F\\u000a ST = 0.148, P < 0.00001). Very little evidence for gene flow among the

Shawn R. Narum; William D. Arnsberg; Andre J. Talbot; Madison S. Powell

2007-01-01

214

Cell specific radiation dosimetry in skeleton from life-span carcinogenesis studies  

SciTech Connect

The osteogenic sarcoma is the dominant life-threatening pathology in lifespan studies of beagles exposed to alpha-emitting bone-seeking radionuclides. It was deduced from these studies that certain skeletal sites are more prone to develop tumors. This project sought to determine the bone cells at risk and their cell-specific radiation dose. The cell-specific radiation dose values are related to loss and high Ra-226 and Pu-239 induced osteogenic sarcoma sites, to test different dose response hypothesis and predict the extent of effects in humans.

Webster, S.S.J.

1993-04-05

215

Cell specific radiation dosimetry in skeleton from life-span carcinogenesis studies. Final report  

SciTech Connect

The osteogenic sarcoma is the dominant life-threatening pathology in lifespan studies of beagles exposed to alpha-emitting bone-seeking radionuclides. It was deduced from these studies that certain skeletal sites are more prone to develop tumors. This project sought to determine the bone cells at risk and their cell-specific radiation dose. The cell-specific radiation dose values are related to loss and high Ra-226 and Pu-239 induced osteogenic sarcoma sites, to test different dose response hypothesis and predict the extent of effects in humans.

Webster, S.S.J.

1993-04-05

216

Diet-derived advanced glycation end products or lipofuscin disrupts proteostasis and reduces life span in Drosophila melanogaster.  

PubMed

Advanced glycation end product (AGE)-modified proteins are formed by the nonenzymatic glycation of free amino groups of proteins and, along with lipofuscin (a highly oxidized aggregate of covalently cross-linked proteins, sugars, and lipids), have been found to accumulate during aging and in several age-related diseases. As the in vivo effects of diet-derived AGEs or lipofuscin remain elusive, we sought to study the impact of oral administration of glucose-, fructose-, or ribose-modified albumin or of artificial lipofuscin in a genetically tractable model organism. We report herein that continuous feeding of young Drosophila flies with culture medium enriched in AGEs or in lipofuscin resulted in reduced locomotor performance and in accelerated rates of AGE-modified proteins and carbonylated proteins accumulation in the somatic tissues and hemolymph of flies, as well as in a significant reduction of flies health span and life span. These phenotypic effects were accompanied by reduced proteasome peptidase activities in both the hemolymph and the somatic tissues of flies and higher levels of oxidative stress; furthermore, oral administration of AGEs or lipofuscin in flies triggered an upregulation of the lysosomal cathepsin B, L activities. Finally, RNAi-mediated cathepsin D knockdown reduced flies longevity and significantly augmented the deleterious effects of AGEs and lipofuscin, indicating that lysosomal cathepsins reduce the toxicity of diet-derived AGEs or lipofuscin. Our in vivo studies demonstrate that chronic ingestion of AGEs or lipofuscin disrupts proteostasis and accelerates the functional decline that occurs with normal aging. PMID:23999505

Tsakiri, Eleni N; Iliaki, Kalliopi K; Höhn, Annika; Grimm, Stefanie; Papassideri, Issidora S; Grune, Tilman; Trougakos, Ioannis P

2013-12-01

217

Metabolism, body size and life span: a case study in evolutionarily divergent populations of the garter snake (Thamnophis elegans).  

PubMed

We present a case study of metabolism, life history and aging in the western terrestrial garter snake (Thamnophis elegans). Early research in the field supported the rate-of-living hypothesis as an explanation of aging, which was based on an apparent negative relationship between mass-specific metabolic rate and lifespan in endotherms. This hypothesis in its original form has not withstood additional tests and comparisons between the two main lineages of endotherms-birds and mammals, but there is still much to be discovered of the causative links among rate of oxygen consumption, physiology and life history, particularly in ectothermic reptiles. We present data that show adult short-lived snakes, from naturally occurring ecotypes of garter snakes, have higher mass-specific resting metabolic rates at any given body mass (metabolic intensity) across a series of normal activity temperatures (15-32°C). The short-lived ecotype in this geographic region reaches a larger body size, and has life-history traits that place it at the fast end of a pace-of-life continuum (fast growth, early maturation, high reproductive output) relative to individuals of the small-bodied long-lived ecotype. The difference between ecotypes in metabolic intensity, even after acclimation to identical conditions, may reflect evolutionary divergence and genetic differences between ecotypes. The difference in metabolic intensity is not, however, present at birth, so an alternative is that developmental environment may permanently influence metabolic rate and life history. Such developmental canalization could lead to altered gene expression via environmental influences on the epigenome and result in altered metabolic trajectories in the snakes' natural habitats. PMID:21558247

Bronikowski, Anne; Vleck, David

2010-11-01

218

Aging in the cerebellum and hippocampus and associated behaviors over the adult life span of CB6F1 mice  

PubMed Central

In the present study we examined the effects of normal aging in the hippocampus and cerebellum, as well as behaviors associated with these substrates. A total of 67 CB6F1 hybrid mice were tested at one of five ages (4, 8, 12, 18 or 25 months) on the context pre-exposure facilitation effect modification of fear conditioning (CPFE), rotorod, Barnes maze, acoustic startle, Morris water maze (MWM) and 500 ms trace eyeblink classical conditioning (EBCC). Behavioral tasks were chosen to increase the ability to detect age-related changes in learning, as trace EBCC is considered a more difficult paradigm (compared to delay EBCC) and the CPFE has been found to be more sensitive to hippocampus insults than standard contextual fear conditioning. To assess the effects of age on the brain, hippocampus volume was calculated and unbiased stereology was used to estimate the number of Purkinje neurons in the cerebellar cortex. A significant, age-related loss of Purkinje neurons was found—beginning at 12 months of age—and hippocampus volume remained stable over the adult life span. Age-related impairment was found, beginning at 12–18 months in the rotorod, and mice with fewer Purkinje neurons showed greater impairment in this task. CB6F1 mice retained auditory acuity across the life span and mice aged 25 months showed significant age-related impairment in the EBCC task; however, deficits were not associated with the loss of Purkinje neurons. Although the CPFE task is considered more sensitive to hippocampus insult, no age-related impairment was found. Spatial memory retention was impaired in the Barnes maze at 25 months, but no significant deficits were seen in the MWM. These results support the finding of differential aging in the hippocampus and cerebellum. PMID:23764510

Kennard, John A.; Brown, Kevin L.; Woodruff-Pak, Diana S.

2013-01-01

219

Sickle cell disease: an opportunity for palliative care across the life span.  

PubMed

Sickle cell disease is a chronic illness that affects patients physically and emotionally and can do so at an early age. An ecological model of palliative care that involves improved communication among the health care team, patients, and their families can be beneficial. Open and honest communication regarding advance care planning, disease management, relief of pain and other symptoms, and bereavement and grief are all important for the patient, family, and health care team. Given the multiple acute and chronic complications of sickle cell disease, an approach to care that is holistic and comprehensive may help to improve a patient's biologic function and the perceived health, functional status, and quality of life of the patient and family. PMID:20804884

Wilkie, Diana J; Johnson, Bonnye; Mack, A Kyle; Labotka, Richard; Molokie, Robert E

2010-09-01

220

A multilevel model analysis of expertise in chess across the life span.  

PubMed

The authors examined longitudinal change in chess skill using a multilevel model analysis of a large database of active, elite chess players (N = 5,011). Parameters estimated from quadratic growth curves indicated that the age of peak performance occurs later in life than originally proposed and that this peak is independent of initial skill level. The findings are also consistent with the hypothesis that aging is slightly kinder to the initially more able, who show milder decline past their peak. Higher tournament activity levels predicted higher ratings overall and interacted with age in the initially more able sample, suggesting that activity had smaller effects on rating for older adults. The authors discuss implications of these findings for lifetime changes in skilled performance. PMID:17563184

Roring, Roy W; Charness, Neil

2007-06-01

221

Feeding into old age: long-term effects of dietary fatty acid supplementation on tissue composition and life span in mice  

PubMed Central

Smaller mammals, such as mice, possess tissues containing more polyunsaturated fatty acids (PUFAs) than larger mammals, while at the same time live shorter lives. These relationships have been combined in the ‘membrane pacemaker hypothesis of aging’. It suggests that membrane PUFA content might determine an animal’s life span. PUFAs in general and certain long-chain PUFAs in particular, are highly prone to lipid peroxidation which brings about a high rate of reactive oxygen species (ROS) production. We hypothesized that dietary supplementation of either n-3 or n-6 PUFAs might affect (1) membrane phospholipid composition of heart and liver tissues and (2) life span of the animals due to the altered membrane composition, and subsequent effects on lipid peroxidation. Therefore, we kept female laboratory mice from the C57BL/6 strain on three diets (n-3 PUFA rich, n-6 PUFA rich, control) and assessed body weights, life span, heart, and liver phospholipid composition after the animals had died. We found that while membrane phospholipid composition clearly differed between feeding groups, life span was not directly affected. However, we were able to observe a positive correlation between monounsaturated fatty acids in cardiac muscle and life span. PMID:20981551

Ruf, Thomas

2010-01-01

222

ATM-dependent phosphorylation of SNEVhPrp19/hPso4 is involved in extending cellular life span and suppression of apoptosis.  

PubMed

Defective DNA repair is widely acknowledged to negatively impact on healthy aging, since mutations in DNA repair factors lead to accelerated and premature aging. However, the opposite, namely if improved DNA repair will also increase the life or health span is less clear, and only few studies have tested if overexpression of DNA repair factors modulates life and health span in cells or organisms. Recently, we identified and characterized SNEVhPrp19/hPso4, a protein that plays a role in DNA repair and pre-mRNA splicing, and observed a doubling of the replicative life span upon ectopic overexpression, accompanied by lower basal DNA damage and apoptosis levels as well as an increased resistance to oxidative stress. Here we find that SNEVhPrp19/hPso4 is phosphorylated at S149 in an ataxia telangiectasia mutated protein (ATM)-dependent manner in response to oxidative stress and DNA double strand break inducing agents. By overexpressing wild-type SNEVhPrp19/hPso4 and a phosphorylation-deficient point-mutant, we found that S149 phosphorylation is necessary for mediating the resistance to apoptosis upon oxidative stress and is partially necessary for elongating the cellular life span. Therefore, ATM dependent phosphorylation of SNEVhPrp19/hPso4 upon DNA damage or oxidative stress might represent a novel axis capable of modulating cellular life span. PMID:22529335

Dellago, Hanna; Khan, Abdulhameed; Nussbacher, Monika; Gstraunthaler, Anna; Lämmermann, Ingo; Schosserer, Markus; Mück, Christoph; Anrather, Dorothea; Scheffold, Annika; Ammerer, Gustav; Jansen-Dürr, Pidder; Rudolph, Karl Lenhard; Voglauer-Grillari, Regina; Grillari, Johannes

2012-04-01

223

Tetrahydroxystilbene glucoside extends mouse life span via upregulating neural klotho and downregulating neural insulin or insulin-like growth factor 1.  

PubMed

A Chinese herb, Polygonatum multiflorum, has been reported to prolong animal life span, but the relevant molecular mechanism remains unclear. Tetrahydroxystilbene glucoside (TSG) is one main component of P. multiflorum and may contribute to extending life span of mammals. On the other hand, neuronal insulin signaling mediates the life span of mammals. Therefore, we investigated the effects of TSG on memory ability, life span, and the neural insulin signaling in the senescence-accelerated prone mouse (SAMP8). TSG improved the memory ability significantly (p < 0.01, compared with a control group). TSG prolonged the life span of SAMP8 by 17% at the most (p < 0.01, compared with a control group). TSG increased the protein level of neural klotho and reduced the levels of neural insulin, insulin-receptor, insulin-like growth factor-1, and insulin-like growth factor-1 receptor in the brain of SAMP8 (p < 0.01, compared with a control group). All these proteins are key factors of the pathways related to neural insulin/IGF-1 signaling. These findings suggest that TSG has anti-aging effects on mammals. From these results, TSG from P. multiflorum should be developed as a potential anti-age drug. PMID:25595496

Zhou, Xuanxuan; Yang, Qian; Xie, Yanhua; Sun, Jiyuan; Hu, Jing; Qiu, Pengcheng; Cao, Wei; Wang, Siwang

2015-03-01

224

Similar causes of various reproductive disorders in early life  

PubMed Central

During the past few decades, scientific evidence has been accumulated concerning the possible adverse effects of the exposure to environmental chemicals on the well-being of wildlife and human populations. One large and growing group of such compounds of anthropogenic or natural origin is referred to as endocrine-disrupting chemicals (EDCs), due to their deleterious action on the endocrine system. This concern was first focused on the control of reproductive function particularly in males, but has later been expanded to include all possible endocrine functions. The present review describes the underlying physiology behind the cascade of developmental events that occur during sexual differentiation of males and the specific role of androgen in the masculinization process and proper organogenesis of the external male genitalia. The impact of the genetic background, environmental exposures and lifestyle factors in the etiology of hypospadias, cryptorchidism and testicular cancer are reviewed and the possible role of EDCs in the development of these reproductive disorders is discussed critically. Finally, the possible direct and programming effects of exposures in utero to widely use therapeutic compounds, environmental estrogens and other chemicals on the incidence of reproductive abnormalities and poor semen quality in humans are also highlighted. PMID:24369133

Svechnikov, Konstantin; Stukenborg, Jan-Bernd; Savchuck, Iuliia; Söder, Olle

2014-01-01

225

The evolution of life histories in garter snakes: Reproduction, aging, and the physiology of trade-offs  

Microsoft Academic Search

Life-history theory predicts that optimal life histories are shaped by trade-offs among traits expressed in different evolutionary and ecological contexts. Fast growth and high reproduction are predicted to trade off with lifespan, with the result that \\

Amanda M. Sparkman

2009-01-01

226

Reduced resistance to oxidative stress during reproduction as a cost of early-life stress.  

PubMed

Stress exposure during early-life development can have long-term consequences for a variety of biological functions including oxidative stress. The link between early-life stress and oxidative balance is beginning to be explored and previous studies have focused on this link in adult non-breeding or immature individuals. However, as oxidative stress is considered as the main physiological mechanism underlying the trade-off between self-maintenance and investment in reproduction, it is necessary to look at the consequences of early-life stress on oxidative status during reproduction. Here, we investigated the effects of exposure to pre- and/or post-natal stress on oxidative balance during reproduction under benign or stressful environmental conditions in an avian model species, the Japanese quail. We determined total antioxidant status (TAS), total oxidant status (TOS) and resistance to a free-radical attack in individual exposed to pre-natal stress, post-natal stress or both and in control individuals exposed to none of the stressors. TAS levels decreased over time in all females that reproduced under stressful conditions. TOS decreased between the beginning and the end of reproductive period in pre-natal control females. In all females, resistance to a free-radical attack decreased over the reproductive event but this decrease was more pronounced in females from a pre-natal stress development. Our results suggest that pre-natal stress may be associated with a higher cost of reproduction in terms of oxidative stress. These results also confirm that early-life stress can be associated with both benefits and costs depending of the life-history stage or environmental context. PMID:25542633

Zimmer, Cédric; Spencer, Karen A

2015-05-01

227

Implications of Extreme Life Span in Clonal Organisms: Millenary Clones in Meadows of the Threatened Seagrass Posidonia oceanica  

PubMed Central

The maximum size and age that clonal organisms can reach remains poorly known, although we do know that the largest natural clones can extend over hundreds or thousands of metres and potentially live for centuries. We made a review of findings to date, which reveal that the maximum clone age and size estimates reported in the literature are typically limited by the scale of sampling, and may grossly underestimate the maximum age and size of clonal organisms. A case study presented here shows the occurrence of clones of slow-growing marine angiosperm Posidonia oceanica at spatial scales ranging from metres to hundreds of kilometres, using microsatellites on 1544 sampling units from a total of 40 locations across the Mediterranean Sea. This analysis revealed the presence, with a prevalence of 3.5 to 8.9%, of very large clones spreading over one to several (up to 15) kilometres at the different locations. Using estimates from field studies and models of the clonal growth of P. oceanica, we estimated these large clones to be hundreds to thousands of years old, suggesting the evolution of general purpose genotypes with large phenotypic plasticity in this species. These results, obtained combining genetics, demography and model-based calculations, question present knowledge and understanding of the spreading capacity and life span of plant clones. These findings call for further research on these life history traits associated with clonality, considering their possible ecological and evolutionary implications. PMID:22312426

Arnaud-Haond, Sophie; Duarte, Carlos M.; Diaz-Almela, Elena; Marbà, Núria; Sintes, Tomas; Serrão, Ester A.

2012-01-01

228

[The course of attention deficit hyperactivity disorder (ADHD) over the life span].  

PubMed

Attention Deficit Hyperactivity Disorder is a neurodevelopmental disorder, associated with the maturation of the nervous system and appearing on a standard proceeding with special cognitive impairments. For many years ADHD was concerned as a typical childhood disorder. Long-term studies though, showed that an important percentage of children with ADHD grew as adults with ADHD. The clinical picture varies with the developmental stage. In pre-school years (3-5 years) the clinical picture is characterized by excessive physical activity, difficulty in cooperation with peers and non-compliance to the recommendations of adults. In school age (6-12 years), apart from the nuclear symptoms of the disorder, as described in the classification systems, i.e. inattention, hyperactivity and impulsivity, oppositional behavior often occurs, conflicts with peers and academic problems. In adolescence hyperactivity lessens, conflicts with parents continue and high risk behaviors often appear. In adults physical activity usually decreases significantly, while inattention and impulsivity still remain. With the passing of time the number of symptoms are usually reduced, however the impact and impairment caused by the disorder remain. The diagnosis of ADHD in adults requires a retrospective diagnosis of ADHD in childhood. Since childhood, comorbid disorders are common, most times continuing until adult life. The Oppositional Defiant Disorder during childhood is related to the presenting of Antisocial Personality Disorder in adults. On the other hand, emotional disorders, which are also rather common in children, adolescents and adults with ADHD, can be due to either common biological mechanisms or the long-standing effect of psychosocial and environmental factors which follow people with ADHD. The relationship between ADHD and substance abuse has been a subject of research, with the view of the existence of Conduct Disorder being necessary for a person to present a Substance Use Disorder, currently prevailing. Smoking and alcohol drinking do not seem to require this mediation and ADHD can be itself a predictor for smoking and alcoholism. Stimulant treatment in childhood offers some protective effect against drug abuse and alcoholism in adolescence. The diagnosis of Borderline Personality Disorder is common in adults with ADHD and the most common reason is the overlap of symptoms between the two disorders. The question is whether the diagnosis of Borderline Personality Disorder in adults is appropriate and useful in the presence of ADHD, because when ADHD proceeds the symptoms and the impairment in functioning are due to this disorder. In general, when another diagnosis or several symptoms as a part of another disorder are also present, treatment of the primary disorder, i.e. ADHD, is beneficial and effective for all the presenting problems. PMID:22796973

Koumoula, A

2012-06-01

229

The role of fecundity and reproductive effort in defining life-history strategies of North American freshwater mussels.  

PubMed

Selection is expected to optimize reproductive investment resulting in characteristic trade-offs among traits such as brood size, offspring size, somatic maintenance, and lifespan; relative patterns of energy allocation to these functions are important in defining life-history strategies. Freshwater mussels are a diverse and imperiled component of aquatic ecosystems, but little is known about their life-history strategies, particularly patterns of fecundity and reproductive effort. Because mussels have an unusual life cycle in which larvae (glochidia) are obligate parasites on fishes, differences in host relationships are expected to influence patterns of reproductive output among species. I investigated fecundity and reproductive effort (RE) and their relationships to other life-history traits for a taxonomically broad cross section of North American mussel diversity. Annual fecundity of North American mussel species spans nearly four orders of magnitude, ranging from < 2000 to 10 million, but most species have considerably lower fecundity than previous generalizations, which portrayed the group as having uniformly high fecundity (e.g. > 200000). Estimates of RE also were highly variable, ranging among species from 0.06 to 25.4%. Median fecundity and RE differed among phylogenetic groups, but patterns for these two traits differed in several ways. For example, the tribe Anodontini had relatively low median fecundity but had the highest RE of any group. Within and among species, body size was a strong predictor of fecundity and explained a high percentage of variation in fecundity among species. Fecundity showed little relationship to other life-history traits including glochidial size, lifespan, brooding strategies, or host strategies. The only apparent trade-off evident among these traits was the extraordinarily high fecundity of Leptodea, Margaritifera, and Truncilla, which may come at a cost of greatly reduced glochidial size; there was no relationship between fecundity and glochidial size for the remaining 61 species in the dataset. In contrast to fecundity, RE showed evidence of a strong trade-off with lifespan, which was negatively related to RE. The raw number of glochidia produced may be determined primarily by physical and energetic constraints rather than selection for optimal output based on differences in host strategies or other traits. By integrating traits such as body size, glochidial size, and fecundity, RE appears more useful in defining mussel life-history strategies. Combined with trade-offs between other traits such as growth, lifespan, and age at maturity, differences in RE among species depict a broad continuum of divergent strategies ranging from strongly r-selected species (e.g. tribe Anodontini and some Lampsilini) to K-selected species (e.g. tribes Pleurobemini and Quadrulini; family Margaritiferidae). Future studies of reproductive effort in an environmental and life-history context will be useful for understanding the explosive radiation of this group of animals in North America and will aid in the development of effective conservation strategies. PMID:23445204

Haag, Wendell R

2013-08-01

230

Two Reproductive Life History Types of Kokanee, Onchorynchus nerka , Exhibit Multivariate Morphometric and Protein Genetic Differentiation  

Microsoft Academic Search

Two reproductive types of kokanee are found in Okanagan Lake, British Columbia: one form that spawns in streams, and another that spawns approximately 2–4 weeks later along beaches of the lake. We examined the levels and patterns of genetic and morphometric variation among three populations (1 beach and 2 stream populations) to better understand life history differentiation. We assayed allozyme

Gary A. Winans; Susan Pollard; David R. Kuligowski

2003-01-01

231

Reproductive Stage of the Life Cycle in the Rhizocephalan Barnacle Polyascus polygenea (Crustacea: Cirripedia)  

Microsoft Academic Search

The specific features of the reproductive stage of the life cycle have been studied in the rhizocephalan barnacle Polyascus polygenea, a parasite of the coastal crab Hemigrapsus sanguineus. It is shown that a single crab can bear 1 to 8 externae of P. polygenea. The fecundity of the parasite depends on the size of the externae and their number on

O. M. Korn; A. I. Shukalyuk; A. V. Trofimova; V. V. Isaeva

2004-01-01

232

Individual quality, early-life conditions, and reproductive success in contrasted populations of large herbivores  

Microsoft Academic Search

Variations among individuals in phenotypic quality and fitness often confound analyses of life-history strategies assessed at the population level. We used detailed long-term data from three populations of large herbivores with generation times ranging from four to nine years to quantify heterogeneity in individual quality among females, and to assess its influence on mean annual reproductive success over the lifetime

Sandra Hamel; Jean-Michel Gaillard; Marco Festa-Bianchet; Steeve D. Côté

2009-01-01

233

Reproduction and early life history of northern squawfish, Ptychocheilus oregonensis , in Idaho's St. Joe River  

Microsoft Academic Search

Synopsis Reproduction and early life history of northern squawfish,Ptychocheilus oregonensis, was investigated in Idaho's St. Joe River from 1980–1981. Spawning occurs in large aggregations which mill near the substrate to broadcast eggs and milt. Males greatly outnumber females in the aggregations. Males mature at smaller sizes and younger ages, and exhibit slower growth and greater mortality than females, although females

Raymond C. Beamesderfer

1992-01-01

234

Effects of shortened host life span on the evolution of parasite life history and virulence in a microbial host-parasite system  

PubMed Central

Background Ecological factors play an important role in the evolution of parasite exploitation strategies. A common prediction is that, as shorter host life span reduces future opportunities of transmission, parasites compensate with an evolutionary shift towards earlier transmission. They may grow more rapidly within the host, have a shorter latency time and, consequently, be more virulent. Thus, increased extrinsic (i.e., not caused by the parasite) host mortality leads to the evolution of more virulent parasites. To test these predictions, we performed a serial transfer experiment, using the protozoan Paramecium caudatum and its bacterial parasite Holospora undulata. We simulated variation in host life span by killing hosts after 11 (early killing) or 14 (late killing) days post inoculation; after killing, parasite transmission stages were collected and used for a new infection cycle. Results After 13 cycles (? 300 generations), parasites from the early-killing treatment were less infectious, but had shorter latency time and higher virulence than those from the late-killing treatment. Overall, shorter latency time was associated with higher parasite loads and thus presumably with more rapid within-host replication. Conclusion The analysis of the means of the two treatments is thus consistent with theory, and suggests that evolution is constrained by trade-offs between virulence, transmission and within-host growth. In contrast, we found little evidence for such trade-offs across parasite selection lines within treatments; thus, to some extent, these traits may evolve independently. This study illustrates how environmental variation (experienced by the host) can lead to the evolution of distinct parasite strategies. PMID:19320981

Nidelet, Thibault; Koella, Jacob C; Kaltz, Oliver

2009-01-01

235

RESEARCH ARTICLE Demography, Female Life History, and Reproductive  

E-print Network

-five females that were observed from middle age (18­33 yr) to death in older age (31­48) gave Contract grant ZAMMA1 1 Department of Zoology, Graduate School of Science, Kyoto University, Kyoto, Japan 2 School, Primate Research Institute, Kyoto University, Kyoto, Japan 4 Department of Life and Cognitive Sciences

236

Senescence and life span  

Microsoft Academic Search

Senescence is a general cellular process that occurs as a response to stress and damage. It forms an alternative response\\u000a of cells to damage that might otherwise cause programmed cell death. Whereas telomere shortening leading to telomere dysfunction\\u000a was the first described cause of senescence, it is now known that senescence can result from many sources of damage. Senescent\\u000a cells

Peter J. Hornsby; Pflugers Arch; Eur J Physiol

2010-01-01

237

The spin-trap N-tert-alpha-phenyl-butylnitrone prolongs the life span of the senescence accelerated mouse.  

PubMed

Free radicals and oxidative damage have been proposed as underlying factors in aging, in chronic and degenerative diseases of aging and in acute clinical conditions. To test involvement of free-radicals in such processes, spin trapping agents which quench more reactive radicals to produce long-lived stable radical adducts have been used as an experimental strategy. Spin traps protect against oxidatively induced injury in numerous in vitro and in vivo model systems involving different organs. A model system for mammalian aging is afforded by the senescence accelerated mouse (SAM-P8), which exhibits many features characteristic of mammalian aging but with a much shortened lifespan. Daily intraperitoneal injection of the spin trap N-tert-alpha-phenyl-butylnitrone (PBN) was administered to male or female mice after they reached maturity at 3 months of age. PBN treated animals as compared with control sham injected animals revealed a remarkable extension of the mean life span in both male and female populations. Overall, a 50% mean survival rate was found of 42 weeks for control as compared to 56 weeks for the PBN administered groups. These results show that the spin trap PBN can prolong lifespan and support the free radical theory of aging. PMID:7598714

Edamatsu, R; Mori, A; Packer, L

1995-06-26

238

Life span and stress resistance of Caenorhabditis elegans are differentially affected by glutathione transferases metabolizing 4-hydroxynon-2-enal  

PubMed Central

The lipid peroxidation product 4-hydroxynon-2-enal (4-HNE) forms as a consequence of oxidative stress, and acts as a signaling molecule or, at superphysiological levels, as a toxicant. The steady-state concentration of the compound reflects the balance between its generation and its metabolism, primarily through glutathione conjugation. Using an RNAi-based screen, we identified in Caenorhabditis elegans five glutathione transferases (GSTs) capable of catalyzing 4-HNE conjugation. RNAi knock-down of these GSTs (products of the gst-5, gst-6, gst-8, gst-10, and gst-24 genes) sensitized the nematode to electrophilic stress elicited by exposure to 4-HNE. However, interference with the expression of only two of these genes (gst-5 and gst-10) significantly shortened the life span of the organism. RNAi knock-down of the other GSTs resulted in at least as much 4-HNE adducts, suggesting tissue-specificity of effects on longevity. Our results are consistent with the oxidative stress theory of organismal aging, broadened by considering electrophilic stress as a contributing factor. According to this extended hypothesis, peroxidation of lipids leads to the formation of 4-HNE in a chain reaction which amplifies the original damage. 4-HNE then acts as an "aging effector" via the formation of 4-HNE-protein adducts, and a resulting change in protein function. PMID:17157356

Ayyadevara, Srinivas; Dandapat, Abhijit; Singh, Sharda P.; Siegel, Eric R.; Shmookler Reis, Robert J.; Zimniak, Ludwika; Zimniak, Piotr

2007-01-01

239

Differential reproductive responses to stress reveal the role of life-history strategies within a species  

PubMed Central

Life-history strategies describe that ‘slow’- in contrast to ‘fast’-living species allocate resources cautiously towards reproduction to enhance survival. Recent evidence suggests that variation in strategies exists not only among species but also among populations of the same species. Here, we examined the effect of experimentally induced stress on resource allocation of breeding seabirds in two populations with contrasting life-history strategies: slow-living Pacific and fast-living Atlantic black-legged kittiwakes. We tested the hypothesis that reproductive responses in kittiwakes under stress reflect their life-history strategies. We predicted that in response to stress, Pacific kittiwakes reduce investment in reproduction compared with Atlantic kittiwakes. We exposed chick-rearing kittiwakes to a short-term (3-day) period of increased exogenous corticosterone (CORT), a hormone that is released during food shortages. We examined changes in baseline CORT levels, parental care and effects on offspring. We found that kittiwakes from the two populations invested differently in offspring when facing stress. In response to elevated CORT, Pacific kittiwakes reduced nest attendance and deserted offspring more readily than Atlantic kittiwakes. We observed lower chick growth, a higher stress response in offspring and lower reproductive success in response to CORT implantation in Pacific kittiwakes, whereas the opposite occurred in the Atlantic. Our findings support the hypothesis that life-history strategies predict short-term responses of individuals to stress within a species. We conclude that behaviour and physiology under stress are consistent with trade-off priorities as predicted by life-history theory. We encourage future studies to consider the pivotal role of life-history strategies when interpreting inter-population differences of animal responses to stressful environmental events. PMID:24089339

Schultner, J.; Kitaysky, A. S.; Gabrielsen, G. W.; Hatch, S. A.; Bech, C.

2013-01-01

240

A cost–benefit analysis of acclimation to low irradiance in tropical rainforest tree seedlings: leaf life span and payback time for leaf deployment  

PubMed Central

The maintenance in the long run of a positive carbon balance under very low irradiance is a prerequisite for survival of tree seedlings below the canopy or in small gaps in a tropical rainforest. To provide a quantitative basis for this assumption, experiments were carried out to determine whether construction cost (CC) and payback time for leaves and support structures, as well as leaf life span (i) differ among species and (ii) display an irradiance-elicited plasticity. Experiments were also conducted to determine whether leaf life span correlates to CC and payback time and is close to the optimal longevity derived from an optimization model. Saplings from 13 tropical tree species were grown under three levels of irradiance. Specific-CC was computed, as well as CC scaled to leaf area at the metamer level. Photosynthesis was recorded over the leaf life span. Payback time was derived from CC and a simple photosynthesis model. Specific-CC displayed only little interspecific variability and irradiance-elicited plasticity, in contrast to CC scaled to leaf area. Leaf life span ranged from 4 months to >26 months among species, and was longest in seedlings grown under lowest irradiance. It was always much longer than payback time, even under the lowest irradiance. Leaves were shed when their photosynthesis had reached very low values, in contrast to what was predicted by an optimality model. The species ranking for the different traits was stable across irradiance treatments. The two pioneer species always displayed the smallest CC, leaf life span, and payback time. All species displayed a similar large irradiance-elicited plasticity. PMID:21511904

Coste, Sabrina; Roggy, Jean-Christophe; Schimann, Heidy; Epron, Daniel; Dreyer, Erwin

2011-01-01

241

Sexual dimorphism in life history: age, survival, and reproduction in male and female field crickets Teleogryllus commodus under seminatural conditions.  

PubMed

Males and females differ in their reproductive strategies. Accordingly, sexually dimorphic optima in the allocation of resources to reproduction should select for sex-specific life histories, including sex-specific resolution of the key trade-off between reproduction and longevity. While males are expected to increase reproductive effort with increasing age under sexual selection theory, female reproductive effort should rather decrease after maturity, due to waning selection pressure at older ages. Sex differences in reproductive trade-offs and in the external mortality hazards experienced during the population's evolutionary history are both likely to shape sex differences in reproductive and actuarial (age-specific mortality) aging. Despite the importance of small-bodied, short-lived animals as laboratory models for life-history and aging studies, very little is known about sex differences in life-history patterns under natural conditions. Here, we tested for sex-specific patterns of reproductive and actuarial aging in field crickets under near-natural conditions. Both males and females showed actuarial senescence, with females exhibiting more rapid aging than males but with a later onset. Female and male reproductive effort showed a senescent decrease, with the peaks at different ages. Our findings provide the first demonstration of sexual dimorphism in age-dependent patterns of both survival and reproduction in an insect under near-natural conditions. PMID:19374505

Zajitschek, Felix; Bonduriansky, Russell; Zajitschek, Susanne R K; Brooks, Robert C

2009-06-01

242

Care and the self: biotechnology, reproduction, and the good life  

PubMed Central

This paper explores a novel philosophy of ethical care in the face of burgeoning biomedical technologies. I respond to a serious challenge facing traditional bioethics with its roots in analytic philosophy. The hallmarks of these traditional approaches are reason and autonomy, founded on a belief in the liberal humanist subject. In recent years, however, there have been mounting challenges to this view of human subjectivity, emerging from poststructuralist critiques, such as Michel Foucault's, but increasingly also as a result of advances in biotechnology itself. In the face of these developments, I argue that the theoretical relevance and practical application of mainstream bioethics is increasingly under strain. Traditionalists will undoubtedly resist. Together, professional philosopher-bioethicists, public health policymakers, and the global commercial healthcare industry tend to respond conservatively by shoring up the liberal humanist subject as the foundation for medical ethics and consumer decision-making, appealing to the familiar tropes of reason, autonomy, and freedom. I argue for a different approach to bioethics, and work towards a new way to conceive of ethical relations in healthcare – one that does not presume a sovereign subject as the basis of dignity, personhood or democracy. Instead, I am critical of the narrow instantiations of reason, autonomy, and freedom, which, more recently, have been co-opted by a troubling neo-liberal politics of the self. Thus, I am critical of current trends in medical ethics, often running in tandem with corporate-governmental models of efficiency, accountability, and so-called evidence-based best practices. As an example of such market-driven conceptions of subjectivity, I discuss the paradigm of "self-care." Self-care shores up the traditional view of the self as a free agent. In this sense, self-care is looked upon favourably by mainstream bioethics in its focus on autonomy, while healthcare policy endorses this model for ideological and economic reasons. To contrast this, I propose a different model of care together with a different model of selfhood. Here I develop and apply Foucault's late work on the "care of the self." In this understanding of "care," I suggest that we might work towards an ethical self that is more commensurable both with recent theoretical views on subjectivity and – more pressingly – with the challenges of emergent biotechnologies. I end this paper with a discussion on ethical parenthood, which offers a practical reading of the "care of the self" in relation to new reproductive technologies (NRTs). PMID:17480234

Murray, Stuart J

2007-01-01

243

Copepod reproductive strategies: life-history theory, phylogenetic pattern and invasion of inland waters  

NASA Astrophysics Data System (ADS)

Life-history theory predicts that different reproductive strategies should evolve in environments that differ in resource availability, mortality, seasonality, and in spatial or temporal variation. Within a population, the predicted optimal strategy is driven by tradeoffs that are mediated by the environment in which the organisms live. At the same time, phylogenetic history may circumscribe natural selection by dictating the range of phenotypes upon which selection can act, or by limiting the range of environments encountered. Comparisons of life-history patterns in related organisms provide a powerful tool for understanding both the nature of selection on life-history characters and the diversity of life-history patterns observed in nature. Here, we explore reproductive strategies of the Copepoda, a well defined group with many phylogenetically independent transitions from free-living to parasitic life styles, from marine to inland waters, and from active development to diapause. Most species are iteroparous annuals, and most (with the exception of some parasitic taxa) develop through a relatively restricted range of life-history stages (nauplii and copepodids, or some modification thereof). Within these bounds, we suggest that there may be a causal relationship between the success of numerous copepod taxa in inland waters and the prevalence of either diapause or parasitism within these groups. We hypothesize that inland waters are more variable spatially and temporally than marine habitats, and accordingly, we interpret diapause and parasitism as mechanisms for coping with environmental variance.

Hairston, Nelson G.; Bohonak, Andrew J.

1998-06-01

244

Environmental contingency in life history strategies: the influence of mortality and socioeconomic status on reproductive timing.  

PubMed

Why do some people have children early, whereas others delay reproduction? By considering the trade-offs between using one's resources for reproduction versus other tasks, the evolutionary framework of life history theory predicts that reproductive timing should be influenced by mortality and resource scarcity. A series of experiments examined how mortality cues influenced the desire to have children sooner rather than later. The effects of mortality depended critically on whether people grew up in a relatively resource-scarce or resource-plentiful environment. For individuals growing up relatively poor, mortality cues produced a desire to reproduce sooner--to want children now, even at the cost of furthering one's education or career. Conversely, for individuals growing up relatively wealthy, mortality cues produced a desire to delay reproduction--to further one's education or career before starting a family. Overall, mortality cues appear to shift individuals into different life history strategies as a function of childhood socioeconomic status, suggesting important implications for how environmental factors can influence fertility and family size. PMID:20873933

Griskevicius, Vladas; Delton, Andrew W; Robertson, Theresa E; Tybur, Joshua M

2011-02-01

245

Life History and Reproductive Timing of the Endangered Illinois Cave Amphipod, Gammarus acherondytes  

NASA Astrophysics Data System (ADS)

To aid the recovery of endangered species requires an understanding of their basic biology. Armed with such knowledge, meaningful management plans with realistic objectives can be established. We examined the life history and reproductive biology of Gammarus acherondytes, a federally endangered cave amphipod, in Reverse Stream, Monroe Co., Illinois. The population was sampled non-destructively at monthly intervals from October 2003 to February 2005. The density of gravid females peaked twice annually, (November-December and June-July) indicating major reproductive events. Gravid females also occurred at other times of the year but at low densities. Two major peaks in the density of newborn young were also observed, which lagged the density of gravid females by approximately 1-2 months. We believe this reproductive pattern is related to the influx of organic matter from mid summer storm events and leaf abscission in autumn. Young grew at a rate of 0.034 mm/day and likely reach reproductive size in one year. Adults are iteroparous and may live for several years. Our results suggest that limiting cave access in highly visited caves during peak reproduction may be a simple strategy to increase the abundance of G. acherondytes.

Venarsky, M. P.; Wilhelm, F. M.; Anderson, F. A.; Taylor, S. J.

2005-05-01

246

Body Size, Growth and Life Span: Implications for the Polewards Range Shift of Octopus tetricus in South-Eastern Australia  

PubMed Central

Understanding the response of any species to climate change can be challenging. However, in short-lived species the faster turnover of generations may facilitate the examination of responses associated with longer-term environmental change. Octopus tetricus, a commercially important species, has undergone a recent polewards range shift in the coastal waters of south-eastern Australia, thought to be associated with the southerly extension of the warm East Australian Current. At the cooler temperatures of a polewards distribution limit, growth of a species could be slower, potentially leading to a bigger body size and resulting in a slower population turnover, affecting population viability at the extreme of the distribution. Growth rates, body size, and life span of O. tetricus were examined at the leading edge of a polewards range shift in Tasmanian waters (40°S and 147°E) throughout 2011. Octopus tetricus had a relatively small body size and short lifespan of approximately 11 months that, despite cooler temperatures, would allow a high rate of population turnover and may facilitate the population increase necessary for successful establishment in the new extended area of the range. Temperature, food availability and gender appear to influence growth rate. Individuals that hatched during cooler and more productive conditions, but grew during warming conditions, exhibited faster growth rates and reached smaller body sizes than individuals that hatched into warmer waters but grew during cooling conditions. This study suggests that fast growth, small body size and associated rapid population turnover may facilitate the range shift of O. tetricus into Tasmanian waters. PMID:25090250

Ramos, Jorge E.; Pecl, Gretta T.; Moltschaniwskyj, Natalie A.; Strugnell, Jan M.; León, Rafael I.; Semmens, Jayson M.

2014-01-01

247

Evaluation of platelet thromboxane radioimmunoassay method to measure platelet life-span: Comparison with /sup 111/indium-platelet method  

SciTech Connect

The platelet activation during radiolabeling in vitro with Cr-51 and In-111 may affect the platelet life-span (PLS) in vivo. A new RIA method to measure PLS is being evaluated. Aspirin inhibits platelet thromboxane (TxA/sub 2/) by acetylating cyclooxygenase. The time required for the TxA/sub 2/ levels to return towards control values depends on the rate of new platelets entering circulation and is a measure of PLS. A single dose of aspirin (150mg) was given to 5 normal human subjects. Blood samples were collected for 2 days before aspirin and daily for 10 days. TxA/sub 2/ production in response to endogenous thrombin was studied by allowing 1 ml blood sample to clot at 37/sup 0/C for 90 min. Serum TxB/sub 2/ (stable breakdown product of Tx-A/sub 2/) levels determined by RIA technique. The plot of TxB/sub 2/ levels (% control) against time showed a gradual increase. The PLS calculated by linear regression analysis assuming a 2-day lag period before cyclooxygenase recovery is 9.7 +- 2.37. In the same 5 subjects, platelets from a 50ml blood sample were labeled with /sup 111/In-tropolone in 2 ml autologous plasma. Starting at 1 hr after injection of labeled platelets, 10 blood samples were obtained over a 8 day period. The PLS calculated based on a linear regression analysis is 10.2 +. 1.4. The PLS measured from the rate of platelet disappearance from circulation and the rate of platelet regeneration into circulation are quite comparable in normal subjects. TxA/sub 2/ regeneration RIA may provide a method to measure PLS without administering radioactivity to patient.

Vallabhajosula, S.; Machac, J.; Badimon, L.; Lipszyc, H.; Goldsmith, S.J.; Fuster, V.

1985-05-01

248

Trimethylation of Lys36 on H3 restricts gene expression change during aging and impacts life span.  

PubMed

Functional data indicate that specific histone modification enzymes can be key to longevity in Caenorhabditis elegans, but the molecular basis of how chromatin structure modulates longevity is not well understood. In this study, we profiled the genome-wide pattern of trimethylation of Lys36 on histone 3 (H3K36me3) in the somatic cells of young and old Caenorhabditis elegans. We revealed a new role of H3K36me3 in maintaining gene expression stability through aging with important consequences on longevity. We found that genes with dramatic expression change during aging are marked with low or even undetectable levels of H3K36me3 in their gene bodies irrespective of their corresponding mRNA abundance. Interestingly, 3' untranslated region (UTR) length strongly correlates with H3K36me3 levels and age-dependent mRNA expression stability. A similar negative correlation between H3K36me3 marking and mRNA expression change during aging was also observed in Drosophila melanogaster, suggesting a conserved mechanism for H3K36me3 in suppressing age-dependent mRNA expression change. Importantly, inactivation of the methyltransferase met-1 resulted in a decrease in global H3K36me3 marks, an increase in mRNA expression change with age, and a shortened life span, suggesting a causative role of the H3K36me3 marking in modulating age-dependent gene expression stability and longevity. PMID:25838541

Pu, Mintie; Ni, Zhuoyu; Wang, Minghui; Wang, Xiujuan; Wood, Jason G; Helfand, Stephen L; Yu, Haiyuan; Lee, Siu Sylvia

2015-04-01

249

Deletion of Brca2 exon 27 causes hypersensitivity to DNA crosslinks, chromosomal instability, and reduced life span in mice  

NASA Technical Reports Server (NTRS)

The Brca2 tumor-suppressor gene contributes to genomic stability, at least in part by a role in homologous recombinational repair. BRCA2 protein is presumed to function in homologous recombination through interactions with RAD51. Both exons 11 and 27 of Brca2 code for domains that interact with RAD51; exon 11 encodes eight BRC motifs, whereas exon 27 encodes a single, distinct interaction domain. Deletion of all RAD51-interacting domains causes embryonic lethality in mice. A less severe phenotype is seen with BRAC2 truncations that preserve some, but not all, of the BRC motifs. These mice can survive beyond weaning, but are runted and infertile, and die very young from cancer. Cells from such mice show hypersensitivity to some genotoxic agents and chromosomal instability. Here, we have analyzed mice and cells with a deletion of only the RAD51-interacting region encoded by exon 27. Mice homozygous for this mutation (called brca2(lex1)) have a shorter life span than that of control littermates, possibly because of early onsets of cancer and sepsis. No other phenotype was observed in these animals; therefore, the brca2(lex1) mutation is less severe than truncations that delete some BRC motifs. However, at the cellular level, the brca2(lex1) mutation causes reduced viability, hypersensitivity to the DNA interstrand crosslinking agent mitomycin C, and gross chromosomal instability, much like more severe truncations. Thus, the extreme carboxy-terminal region encoded by exon 27 is important for BRCA2 function, probably because it is required for a fully functional interaction between BRCA2 and RAD51. Copyright 2003 Wiley-Liss, Inc.

Donoho, Greg; Brenneman, Mark A.; Cui, Tracy X.; Donoviel, Dorit; Vogel, Hannes; Goodwin, Edwin H.; Chen, David J.; Hasty, Paul

2003-01-01

250

Life tables and reproductive parameters of Lutzomyia spinicrassa (Diptera: Psychodidae) under laboratory conditions.  

PubMed

Lutzomyia spinicrassa is a vector of Leishmania braziliensis in Colombia. This sand fly has a broad geographical distribution in Colombia and Venezuela and it is found mainly in coffee plantations. Baseline biological growth data of L. spinicrassa were obtained under experimental laboratory conditions. The development time from egg to adult ranged from 59 to 121 days, with 12.74 weeks in average. Based on cohorts of 100 females, horizontal life table was constructed. The following predictive parameters were obtained: net rate of reproduction (8.4 females per cohort female), generation time (12.74 weeks), intrinsic rate of population increase (0.17), and finite rate of population increment (1.18). The reproductive value for each class age of the cohort females was calculated. Vertical life tables were elaborated and mortality was described for the generation obtained of the field cohort. In addition, for two successive generations, additive variance and heritability for fecundity were estimated. PMID:15558171

Escovar, Jesús; Bello, Felio J; Morales, Alberto; Moncada, Ligia; Cárdenas, Estrella

2004-10-01

251

Analysis of menstrual, reproductive, and life-style factors for breast cancer risk in Turkish women  

Microsoft Academic Search

The aim of this study was to investigate the association between menstrual, reproductive, and life-style factors and breast\\u000a cancer in Turkish women. In a hospital-based case-control study in Ankara, 622 patients with histologically confirmed breast\\u000a cancer were compared with 622 age-matched controls, admitted to the same hospital for acute and non-neoplastic diseases. Unconditional\\u000a logistic regression was used to estimate odds

Betul Oran; Ismail Celik; Mustafa Erman; Esmen Baltali; Nurullah Zengin; Figen Demirkazik; Sabahat Tezcan

2004-01-01

252

Variation in Male Reproductive Longevity across Traditional Societies  

PubMed Central

Most accounts of human life history propose that women have short reproductive spans relative to their adult lifespans, while men not only remain fertile but carry on reproducing until late life. Here we argue that studies have overlooked evidence for variation in male reproductive ageing across human populations. We apply a Bayesian approach to census data from Agta hunter-gatherers and Gambian farmers to show that long post-reproductive lifespans characterise not only women but also males in some traditional human populations. We calculate three indices of reproductive ageing in men (oldest age at reproduction, male late-life reproduction, and post-reproductive representation) and identify a continuum of male reproductive longevity across eight traditional societies ranging from !Kung, Hadza and Agta hunter-gatherers exhibiting low levels of polygyny, early age at last reproduction and long post-reproductive lifespans, to male Gambian agriculturalists and Turkana pastoralists showing higher levels of polygyny, late-life reproduction and shorter post-reproductive lifespans. We conclude that the uniquely human detachment between rates of somatic senescence and reproductive decline, and the existence of post-reproductive lifespans, are features of both male and female life histories, and therefore not exclusive consequences of menopause. PMID:25405763

Vinicius, Lucio; Mace, Ruth; Migliano, Andrea

2014-01-01

253

Life-span extension from hypoxia in Caenorhabditis elegans requires both HIF-1 and DAF-16 and is antagonized by SKN-1.  

PubMed

Stabilization of the hypoxia-inducible factor (HIF-1) protein extends longevity in Caenorhabditis elegans. However, stabilization of mammalian HIF-1? has been implicated in tumor growth and cancer development. Consequently, for the hypoxic response to benefit mammalian health, we must determine the components of the response that contribute to longevity, and separate them from those that cause harm in mammals. Here, we subject adult worms to low oxygen environments. We find that growth in hypoxia increases longevity in wild-type worms but not in animals lacking HIF-1 or DAF-16. Conversely, hypoxia shortens life span in combination with overexpression of the antioxidant stress response protein SKN-1. When combined with mutations in other longevity pathways or dietary restriction, hypoxia extends life span but to varying extents. Collectively, our results show that hypoxia modulates longevity in a complex manner, likely involving components in addition to HIF-1. PMID:23419779

Leiser, Scott F; Fletcher, Marissa; Begun, Anisoara; Kaeberlein, Matt

2013-10-01

254

Life-Span Extension From Hypoxia in Caenorhabditis elegans Requires Both HIF-1 and DAF-16 and Is Antagonized by SKN-1  

PubMed Central

Stabilization of the hypoxia-inducible factor (HIF-1) protein extends longevity in Caenorhabditis elegans. However, stabilization of mammalian HIF-1? has been implicated in tumor growth and cancer development. Consequently, for the hypoxic response to benefit mammalian health, we must determine the components of the response that contribute to longevity, and separate them from those that cause harm in mammals. Here, we subject adult worms to low oxygen environments. We find that growth in hypoxia increases longevity in wild-type worms but not in animals lacking HIF-1 or DAF-16. Conversely, hypoxia shortens life span in combination with overexpression of the antioxidant stress response protein SKN-1. When combined with mutations in other longevity pathways or dietary restriction, hypoxia extends life span but to varying extents. Collectively, our results show that hypoxia modulates longevity in a complex manner, likely involving components in addition to HIF-1. PMID:23419779

2013-01-01

255

Relationships of leaf dark respiration to leaf nitrogen, specific leaf area and leaf life-span: a test across biomes and functional groups  

Microsoft Academic Search

Based on prior evidence of coordinated multiple leaf trait scaling, we hypothesized that variation among species in leaf\\u000a dark respiration rate (R\\u000a d) should scale with variation in traits such as leaf nitrogen (N), leaf life-span, specific leaf area (SLA), and net photosynthetic\\u000a capacity (A\\u000a max). However, it is not known whether such scaling, if it exists, is similar among

Peter B. Reich; Michael B. Walters; David S. Ellsworth; James M. Vose; John C. Volin; Charles GreshamWilliam; William D. Bowman

1998-01-01

256

Deletion of the life span determinant p66 Shc prevents age-dependent increases in emotionality and pain sensitivity in mice  

Microsoft Academic Search

Oxidative stress has been implicated in the aging process. Previous studies have determined that mice with a targeted mutation of the p66Shc gene show reduced oxidative stress and extended life span. This study is the first behavioral characterization of mice carrying a deletion of p66Shc. Four-, 11- and 24-months-old homozygous knockout and wild-type mice of the 129Sv\\/Ev strain underwent a

Alessandra Berry; Francesca Capone; Marco Giorgio; Pier Giuseppe Pelicci; E. R. de Kloet; Enrico Alleva; Luisa Minghetti; Francesca Cirulli

2007-01-01

257

Life Table Evaluation of Survival and Reproduction of the Aphid, Sitobion avenae, Exposed to Cadmium  

PubMed Central

The effects of cadmium (Cd) on the development, fecundity, and reproduction of the grain aphid, Sitobion avenae Fabricius (Hemiptera: Aphididae) were estimated by constructing a life table of S. avenae exposed to Cd. The concentrations of Cd in the soil were as follows: 0, 10, 20, 40, 80, and 160 mg/kg. The correlation analysis of the Cd concentration in soil and wheat revealed that the amount in the wheat increased with the increase of Cd concentrations in soil. The results indicated that, the latter part of the reproduction period was significantly affected by Cd, according to the curve of the total survival rate (lx). The net reproductive rate (R 0), innate capacity of increase (r), and finite rate of increase (?) of S. avenae all decreased under the stress of Cd, and were lowest at a Cd concentration of 20 mg/kg. Cd also negatively affected fecundity and mx (the number of offspring produced by an individual female). At 20 mg/kg, the decline of them was most obvious. In conclusion, survival and reproduction of S. avenae were inhibited under the treatment of the heavy metal Cd. Sitobion avenae was more sensitive to Cd at concentration of 20 mg/kg compared to the other concentrations. This concentration can be used to examine the mechanisms behind population genetics and biological mutation of S. avenae when exposed to heavy metal. PMID:22958415

Gao, Huan-Huan; Zhao, Hui-Yan; Du, Chao; Deng, Ming-Ming; Du, Er-Xia; Hu, Zu-Qing; Hu, Xiang-Shun

2012-01-01

258

Effects of radiation and lifestyle factors on risks of urothelial carcinoma in the Life Span Study of atomic bomb survivors.  

PubMed

Among the Life Span Study (LSS) of Atomic-bomb survivors, recent estimates showed that unspecified bladder cancer had high radiation sensitivity with a notably high female-to-male excess relative risk (ERR) per radiation dose ratio and were the only sites for which the ERR did not decrease with attained age. These findings, however, did not consider lifestyle factors, which could potentially confound or modify the risk estimates. This study estimated the radiation risks of the most prevalent subtype of urinary tract cancer, urothelial carcinoma, while accounting for smoking, consumption of fruit, vegetables, alcohol and level of education (a surrogate for socioeconomic status). Eligible study subjects included 105,402 (males = 42,890) LSS members who were cancer-free in 1958 and had estimated radiation doses. Members were censored due to loss of follow-up, incident cancer of another type, death, or the end of calendar year 2001. Surveys (by mail or clinical interview) gathered lifestyle data periodically for 1963-1991. There were 63,827 participants in one or more survey. Five hundred seventy-three incident urothelial carcinoma cases occurred, of which 364 occurred after lifestyle information was available. Analyses were performed using Poisson regression methods. The excess relative risk per weighted gray unit (the gamma component plus 10 times the neutron component, Gy(w)) was 1.00 (95% CI: 0.43-1.78) but the risks were not dependent upon age at exposure or attained age. Lifestyle factors other than smoking were not associated with urothelial carcinoma risk. Neither the magnitude of the radiation ERR estimate (1.00 compared to 0.96), nor the female-to-male (F:M) ERR/Gy(w) ratio (3.2 compared to 3.4) were greatly changed after accounting for all lifestyle factors. A multiplicative model of gender-specific radiation and smoking effects was the most revealing though there was no evidence of significant departures from either the additive or multiplicative joint effect models. Among the LSS cohort members with doses greater than 0.005 Gy(w) (average dose 0.21 Gy(w)), the attributable fraction of urothelial carcinoma due to radiation was 7.1% in males and 19.7% in females. Among current smokers, the attributable fraction of urothelial carcinoma due to smoking was 61% in males and 52% in females. Relative risk estimates of smoking risk were approximately two for smokers compared to nonsmokers. After adjustment for lifestyle factors, gender-specific radiation risks and the F:M ERR/Gy(w), the ratios of excess urothelial carcinoma risk were similar to the estimates without adjusting for lifestyle factors. Smoking was the primary factor responsible for excess urothelial carcinoma in this cohort. These findings led us to conclude that the radiation risk estimates of urothelial carcinoma do not appear to be strongly confounded or modified by smoking, consumption of alcohol, fruits, or vegetables, or level of education. PMID:22631857

Grant, E J; Ozasa, K; Preston, D L; Suyama, A; Shimizu, Y; Sakata, R; Sugiyama, H; Pham, T-M; Cologne, J; Yamada, M; De Roos, A J; Kopecky, K J; Porter, M P; Seixas, N; Davis, S

2012-07-01

259

A structured population model suggests that long life and post-reproductive lifespan promote the evolution of cooperation.  

PubMed

Social organization correlates with longevity across animal taxa. This correlation has been explained by selection for longevity by social evolution. The reverse causality is also conceivable but has not been sufficiently considered. We constructed a simple, spatially structured population model of asexually reproducing individuals to study the effect of temporal life history structuring on the evolution of cooperation. Individuals employed fixed strategies of cooperation or defection towards all neighbours in a basic Prisoner?s Dilemma paradigm. Individuals aged and transitioned through different life history stages asynchronously without migration. An individual?s death triggered a reproductive event by one immediate neighbour. The specific neighbour was chosen probabilistically according to the cumulative payoff from all local interactions. Varying the duration of pre-reproductive, reproductive, and post-reproductive life history stages, long-term simulations allowed a systematic evaluation of the influence of the duration of these specific life history stages. Our results revealed complex interactions among the effects of the three basic life history stages and the benefit to defect. Overall, a long post-reproductive stage promoted the evolution of cooperation, while a prolonged pre-reproductive stage has a negative effect. In general, the total length of life also increased the probability of the evolution of cooperation. Thus, our specific model suggests that the timing of life history transitions and total duration of life history stages may affect the evolution of cooperative behaviour. We conclude that the causation of the empirically observed association of life expectancy and sociality may be more complex than previously realized. PMID:25637763

Ross, Caitlin; Rychtá?, Jan; Rueppell, Olav

2015-03-21

260

Early-life reproduction is associated with increased mortality risk but enhanced lifetime fitness in pre-industrial humans.  

PubMed

The physiology of reproductive senescence in women is well understood, but the drivers of variation in senescence rates are less so. Evolutionary theory predicts that early-life investment in reproduction should be favoured by selection at the cost of reduced survival and faster reproductive senescence. We tested this hypothesis using data collected from preindustrial Finnish church records. Reproductive success increased up to age 25 and was relatively stable until a decline from age 41. Women with higher early-life fecundity (ELF; producing more children before age 25) subsequently had higher mortality risk, but high ELF was not associated with accelerated senescence in annual breeding success. However, women with higher ELF experienced faster senescence in offspring survival. Despite these apparent costs, ELF was under positive selection: individuals with higher ELF had higher lifetime reproductive success. These results are consistent with previous observations in both humans and wild vertebrates that more births and earlier onset of reproduction are associated with reduced survival, and with evolutionary theory predicting trade-offs between early reproduction and later-life survival. The results are particularly significant given recent increases in maternal ages in many societies and the potential consequences for offspring health and fitness. PMID:25740893

Hayward, Adam D; Nenko, Ilona; Lummaa, Virpi

2015-04-01

261

Antiretroviral Therapy and Reproductive Life Projects: Mitigating the Stigma of AIDS in Nigeria  

PubMed Central

As millions of people infected with HIV in Africa are increasingly able to live longer and healthier lives because of access to antiretroviral therapy, concerns have emerged that people might eschew protective practices after their health improves. Extending beyond the notion of sexual “disinhibition,” researchers have begun to analyze the sexual behavior of people in treatment through the perspective of their marital and childbearing aspirations. This article explores the reproductive life projects of HIV-positive men and women in southeastern Nigeria, showing how actions that contradict medical advice are understandable in the context of patients’ socially normative desires for marriage and children. Based on in-depth interviews and observations (June–December 2004; June–July 2006; June–July 2007) of people enrolled in the region’s oldest treatment program, we argue that broadly held social expectations with regard to reproduction are experienced even more acutely by HIV-positive people. This is because in Nigeria the stigma associated with AIDS is closely tied to widespread perceptions of social and moral crisis, such that AIDS itself is seen as both a cause and a symptom of anxiety-producing forms of social change. Specifically, in an era of rapid societal transformation, Nigerians see sexual promiscuity and the alienation of young people from traditional obligations to kin and community as indicative of threatened social reproduction. For people who are HIV-positive, marrying and having children offer not only the opportunity to lead normal lives, but also a means to mitigate the stigma associated with the disease. Four ethnographic case studies are provided to exemplify how and why social and personal life projects can trump or complicate medical and public health priorities. These examples suggest that treatment programs must openly address and proactively support the life projects of people on antiretroviral therapy if the full benefits of expanded access to treatment are to be realized. PMID:20494501

Mbakwem, Benjamin C

2010-01-01

262

Experimentally decoupling reproductive investment from energy storage to test the functional basis of a life-history trade-off.  

PubMed

The ubiquitous life-history trade-off between reproduction and survival has long been hypothesized to reflect underlying energy-allocation trade-offs between reproductive investment and processes related to self-maintenance. Although recent work has questioned whether energy-allocation models provide sufficient explanations for the survival cost of reproduction, direct tests of this hypothesis are rare, especially in wild populations. This hypothesis was tested in a wild population of brown anole lizards (Anolis sagrei) using a two-step experiment. First, stepwise variation in reproductive investment was created using unilateral and bilateral ovariectomy (OVX) along with intact (SHAM) control. Next, this manipulation was decoupled from its downstream effects on energy storage by surgically ablating the abdominal fat stores from half of the females in each reproductive treatment. As predicted, unilateral OVX (intermediate reproductive investment) induced levels of growth, body condition, fat storage and breeding-season survival that were intermediate between the high levels of bilateral OVX (no reproductive investment) and the low levels of SHAM (full reproductive investment). Ablation of abdominal fat bodies had a strong and persistent effect on energy stores, but it did not influence post-breeding survival in any of the three reproductive treatments. This suggests that the energetic savings of reduced reproductive investment do not directly enhance post-breeding survival, with the caveat that only one aspect of energy storage was manipulated and OVX itself had no overall effect on post-breeding survival. This study supports the emerging view that simple energy-allocation models may often be insufficient as explanations for the life-history trade-off between reproduction and survival. PMID:24724820

Cox, Robert M; Lovern, Matthew B; Calsbeek, Ryan

2014-04-11

263

Antioxidant Capacity of “Mexican Arnica” Heterotheca inuloides Cass Natural Products and Some Derivatives: Their Anti-Inflammatory Evaluation and Effect on C. elegans Life Span  

PubMed Central

It has been suggested that the accumulation of biomolecular damage caused by reactive oxygen species (ROS) contributes to aging. The antioxidant activity is related to the ability of certain compounds to protect against the potentially harmful effect of processes or reactions involving ROS. This ability is associated with the termination of free radical propagation in biological systems. From Heterotheca inuloides various compounds which have shown to possess antioxidant capacity and scavenging ROS. The aim of this study was to determine the antioxidant capacity of additional natural components isolated from H. inuloides and some semisynthetic derivatives, their anti-inflammatory activity and the effect on Caenorhabditis elegans nematode life span. Compounds showed ability to inhibit various biological processes such as lipid peroxidation, scavenge nonbiological important oxidants such as 1O2, OH?, H2O2, and HOCl and scavenge non biological stable free radicals (DPPH). Some cadinane type compounds showed possess antioxidant, ROS scavenging capacity, anti-inflammatory activity, and effect on the C. elegans life span. Flavonoid type compounds increased the life of the nematode and quercetin was identified as the compound with the greatest activity. The modification of chemical structure led to a change in the antioxidant capacity, the anti-inflammatory activity, and the survival of the worm.

Rodríguez-Chávez, José Luis; Nieto-Camacho, Antonio; Delgado-Lamas, Guillermo

2015-01-01

264

Biodemography of a long-lived tephritid: Reproduction and longevity in a large cohort of female Mexican fruit flies, Anastrepha ludens  

E-print Network

U N C O R R EC TED PR O O F Biodemography of a long-lived tephritid: Reproduction and longevity reproductive rates, and life span were recorded in a laboratory cohort of Mexican fruit flies consisting of egg laying at early ages and both subsequent reproduction and remaining longevity. Discussion includes

Sentürk, Damla

265

Metabolism, Body Size and Life Span: A Case Study in Evolutionarily Divergent Populations of the Garter Snake (Thamnophis elegans)  

E-print Network

of the Garter Snake (Thamnophis elegans) Anne Bronikowski1 and David Vleck Ecology, Evolution and Organismal of metabolism, life history and aging in the western terrestrial garter snake (Thamnophis elegans). Early

Bronikowski, Anne

266

Dmp53, basket and drICE gene knockdown and polyphenol gallic acid increase life span and locomotor activity in a Drosophila Parkinson’s disease model  

PubMed Central

Understanding the mechanism(s) by which dopaminergic (DAergic) neurons are eroded in Parkinson’s disease (PD) is critical for effective therapeutic strategies. By using the binary tyrosine hydroxylase (TH)-Gal4/UAS-X RNAi Drosophila melanogaster system, we report that Dmp53, basket and drICE gene knockdown in dopaminergic neurons prolong life span (p < 0.05; log-rank test) and locomotor activity (p < 0.05; ?2 test) in D. melanogaster lines chronically exposed to (1 mM) paraquat (PQ, oxidative stress (OS) generator) compared to untreated transgenic fly lines. Likewise, knockdown flies displayed higher climbing performance than control flies. Amazingly, gallic acid (GA) significantly protected DAergic neurons, ameliorated life span, and climbing abilities in knockdown fly lines treated with PQ compared to flies treated with PQ only. Therefore, silencing specific gene(s) involved in neuronal death might constitute an excellent tool to study the response of DAergic neurons to OS stimuli. We propose that a therapy with antioxidants and selectively “switching off” death genes in DAergic neurons could provide a means for pre-clinical PD individuals to significantly ameliorate their disease condition. PMID:24385865

Ortega-Arellano, Hector Flavio; Jimenez-Del-Rio, Marlene; Velez-Pardo, Carlos

2013-01-01

267

Budding Yeast SSD1-V Regulates Transcript Levels of Many Longevity Genes and Extends Chronological Life Span in Purified Quiescent Cells  

PubMed Central

Ssd1 is an RNA-binding protein that affects literally hundreds of different processes and is polymorphic in both wild and lab yeast strains. We have used transcript microarrays to compare mRNA levels in an isogenic pair of mutant (ssd1-d) and wild-type (SSD1-V) cells across the cell cycle. We find that 15% of transcripts are differentially expressed, but there is no correlation with those mRNAs bound by Ssd1. About 20% of cell cycle regulated transcripts are affected, and most show sharper amplitudes of oscillation in SSD1-V cells. Many transcripts whose gene products influence longevity are also affected, the largest class of which is involved in translation. Ribosomal protein mRNAs are globally down-regulated by SSD1-V. SSD1-V has been shown to increase replicative life span¤ and we show that SSD1-V also dramatically increases chronological life span (CLS). Using a new assay of CLS in pure populations of quiescent prototrophs, we find that the CLS for SSD1-V cells is twice that of ssd1-d cells. PMID:19570907

Li, Lihong; Lu, Yong; Qin, Li-Xuan; Bar-Joseph, Ziv; Werner-Washburne, Margaret

2009-01-01

268

Human telomerase reverse transcriptase and glucose-regulated protein 78 increase the life span of articular chondrocytes and their repair potential  

PubMed Central

Background Like all mammalian cells, normal adult chondrocytes have a limited replicative life span, which decreases with age. To facilitate the therapeutic use of chondrocytes from older donors, a method is needed to prolong their life span. Methods We transfected chondrocytes with hTERT or GRP78 and cultured them in a 3-dimensional atelocollagen honeycomb-shaped scaffold with a membrane seal. Then, we measured the amount of nuclear DNA and glycosaminoglycans (GAGs) and the expression level of type II collagen as markers of cell proliferation and extracellular matrix formation, respectively, in these cultures. In addition, we allografted this tissue-engineered cartilage into osteochondral defects in old rabbits to assess their repair activity in vivo. Results Our results showed different degrees of differentiation in terms of GAG content between chondrocytes from old and young rabbits. Chondrocytes that were cotransfected with hTERT and GRP78 showed higher cellular proliferation and expression of type II collagen than those of nontransfected chondrocytes, regardless of the age of the cartilage donor. In addition, the in vitro growth rates of hTERT- or GRP78-transfected chondrocytes were higher than those of nontransfected chondrocytes, regardless of donor age. In vivo, the tissue-engineered cartilage implants exhibited strong repairing activity, maintained a chondrocyte-specific phenotype, and produced extracellular matrix components. Conclusions Focal gene delivery to aged articular chondrocytes exhibited strong repairing activity and may be therapeutically useful for articular cartilage regeneration. PMID:22472071

2012-01-01

269

Enhanced early-life nutrition promotes hormone production and reproductive development in Holstein bulls.  

PubMed

Holstein bull calves often reach artificial insemination centers in suboptimal body condition. Early-life nutrition is reported to increase reproductive performance in beef bulls. The objective was to determine whether early-life nutrition in Holstein bulls had effects similar to those reported in beef bulls. Twenty-six Holstein bull calves were randomly allocated into 3 groups at approximately 1 wk of age to receive a low-, medium-, or high-nutrition diet, based on levels of energy and protein, from 2 to 31 wk of age. Calves were on their respective diets until 31 wk of age, after which they were all fed a medium-nutrition diet. To evaluate secretion profiles and concentrations of blood hormones, a subset of bulls was subjected to intensive blood sampling every 4 wk from 11 to 31 wk of age. Testes of all bulls were measured once a month; once scrotal circumference reached 26cm, semen collection was attempted (by electroejaculation) every 2 wk to confirm puberty. Bulls were maintained until approximately 72 wk of age and then slaughtered at a local abattoir. Testes were recovered and weighed. Bulls fed the high-nutrition diet were younger at puberty (high=324.3 d, low=369.3 d) and had larger testes for the entire experimental period than bulls fed the low-nutrition diet. Bulls fed the high-nutrition diet also had an earlier and more substantial early rise in LH than those fed the low-nutrition diet and had increased concentrations of insulin-like growth factor-I (IGF-I) earlier than the bulls fed the low-nutrition diet. Furthermore, we detected a temporal association between increased IGF-I concentrations and an early LH rise in bulls fed the high-nutrition diet. Therefore, we inferred that IGF-I had a role in regulating the early gonadotropin rise (in particular, LH) and thus reproductive development of Holstein bulls. Overall, these results support our hypothesis that Holstein bull calves fed a high-nutrition diet reach puberty earlier and have larger testes than those fed a low-nutrition diet, and they provide clear evidence that nutritional modulation of Holstein bull calves during early life has profound effects on reproductive development. PMID:25497791

Dance, Alysha; Thundathil, Jacob; Wilde, Randy; Blondin, Patrick; Kastelic, John

2015-02-01

270

Reproductive problems directly attributable to long-term captivity--asymmetric reproductive aging.  

PubMed

Problems attributable to long-term captivity have been identified and are responsible for the difficulties in establishing successful reproduction in captive populations of wildlife, specifically, elephants and rhinoceroses. Historically, non-reproductive periods of 10-15 years in nulliparous female rhinoceroses and elephants have not been considered problematic. New evidence suggests that prolonged exposure to endogenous sex steroids and that long stretches of non-reproductive periods induce asymmetric reproductive aging in captive animals. The consequences are reduced fertility, shortened reproductive life-span and, eventually, irreversible acyclicity. Although age-related reproductive lesions have also been documented in male rhinoceroses, they continue to maintain a longer reproductive life-span than females. Since human and domestic animal models have already indicated that early pregnancy provides natural protective mechanism against asymmetric reproductive aging processes and premature senescence, it is imperative that appropriate counter measures such as assisted reproductive technologies (ART) be utilized to ensure early pregnancy in captive animals for their preservation and to ensure increased genetic diversity of the captive populations. PMID:15271443

Hermes, R; Hildebrandt, T B; Göritz, F

2004-07-01

271

Reproductive versus somatic tissue growth during the life cycle of the cuttlefish Sepia pharaonis Ehrenberg, 1831  

Microsoft Academic Search

The effect of maturation on relative growth of somatic tissues was investigated by measuring and compar- ing monthly changes in dry weight of somatic tissues and reproductive or- gans. In both sexes, reproductive tis- sues grew in relation to total body mass; at maturity female reproductive tissue was 16% of total dry body mass, whereas male reproductive tissue was 2.6%.

Howaida R. Gabr; Roger T. Hanlon; Salah G. El-Etreby; Mahmoud H. Hanafy

272

INTEGR. COMP. BIOL., 45:500510 (2005) Sex-linked Correlated Responses in Female Reproductive Traits to Selection on Male Eye Span  

E-print Network

responses to selection were due, in part, to X- linked genes in linkage disequilibrium or that exhibit on Drosophila melanogaster have shown that selection for longer sperm leads to changes in female sperm storage500 INTEGR. COMP. BIOL., 45:500­510 (2005) Sex-linked Correlated Responses in Female Reproductive

Wilkinson, Gerald S.

2005-01-01

273

Dead or alive: Deformed Wing Virus and Varroa destructor reduce the life span of winter honey bees  

Technology Transfer Automated Retrieval System (TEKTRAN)

Elevated winter losses of managed honey bee colonies are a major concern, but the underlying mechanisms remain controversial. Among suspects are the parasitic mite Varroa destructor, the microsporidian Nosema ceranae and associated viruses. Here, we hypothesize that pathogens reduce the life expecta...

274

Stereotypes of Women in Different Stages of Their Reproductive Life: Data From Mexico and the United States  

Microsoft Academic Search

College students from Mexico and the United States (n = 349) were surveyed to explore stereotypes regarding women in different menstrual cycle phases and other stages of reproductive life. Participants from both countries defined a premenstrual or menstrual woman as irritable and moody and a menopausal woman as old and irritable. A woman with a hysterectomy was defined as sad,

Ma. Luisa Marván; Martha Islas; Laura Vela; Joan C. Chrisler; Elyse A. Warren

2008-01-01

275

The Study of Life Review. An Approach to the Investigation of Intellectual Development across the Life Span. Studien und Berichte 47.  

ERIC Educational Resources Information Center

A study looked for age differences in the quality of responses to the Life Review Task (LRT), studied the LRT itself as a tool for exploring wisdom and intellectual functioning in adulthood, and considered personality characteristics and life experience as alternative predictors of response quality. Sixty-three West German women of different ages…

Staudinger, Ursula M.

276

A unifying perspective on personality pathology across the life span: developmental considerations for the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders.  

PubMed

Proposed changes in the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-V) include replacing current personality disorder (PD) categories on Axis II with a taxonomy of dimensional maladaptive personality traits. Most of the work on dimensional models of personality pathology, and on personality disorders per se, has been conducted on young and middle-aged adult populations. Numerous questions remain regarding the applicability and limitations of applying various PD models to early and later life. In the present paper, we provide an overview of such dimensional models and review current proposals for conceptualizing PDs in DSM-V. Next, we extensively review existing evidence on the development, measurement, and manifestation of personality pathology in early and later life focusing on those issues deemed most relevant for informing DSM-V. Finally, we present overall conclusions regarding the need to incorporate developmental issues in conceptualizing PDs in DSM-V and highlight the advantages of a dimensional model in unifying PD perspectives across the life span. PMID:19583880

Tackett, Jennifer L; Balsis, Steve; Oltmanns, Thomas F; Krueger, Robert F

2009-01-01

277

A unifying perspective on personality pathology across the life span: Developmental considerations for the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders  

PubMed Central

Proposed changes in the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-V) include replacing current personality disorder (PD) categories on Axis II with a taxonomy of dimensional maladaptive personality traits. Most of the work on dimensional models of personality pathology, and on personality disorders per se, has been conducted on young and middle-aged adult populations. Numerous questions remain regarding the applicability and limitations of applying various PD models to early and later life. In the present paper, we provide an overview of such dimensional models and review current proposals for conceptualizing PDs in DSM-V. Next, we extensively review existing evidence on the development, measurement, and manifestation of personality pathology in early and later life focusing on those issues deemed most relevant for informing DSM-V. Finally, we present overall conclusions regarding the need to incorporate developmental issues in conceptualizing PDs in DSM-V and highlight the advantages of a dimensional model in unifying PD perspectives across the life span. PMID:19583880

TACKETT, JENNIFER L.; BALSIS, STEVE; OLTMANNS, THOMAS F.; KRUEGER, ROBERT F.

2010-01-01

278

Assessing the burden of sexual and reproductive ill-health: questions regarding the use of disability-adjusted life years.  

PubMed Central

The use of the disability-adjusted life year (DALY) as the unit in which to calculate the burden of disease associated with reproductive ill-health has given rise to considerable debate. Criticisms include the failure to address the problem of missing and inadequate epidemiological data, inability to deal adequately with co-morbidities, and lack of transparency in the process of ascribing disability weights to sexual and reproductive health conditions. Many of these criticisms could be addressed within the current DALY framework and a number of suggestions to do so are made. These suggestions include: (1) developing an international research strategy to determine the incidence and prevalence of reproductive ill-health and diseases, including the risk of long-term complications; (2) undertaking a research strategy using case studies, population-based surveillance data and longitudinal studies to identify, evaluate and utilize more of the existing national data sources on sexual and reproductive health; (3) comprehensively mapping the natural history of sexual and reproductive health conditions--in males and in females--and their sequelae, whether physical or psychological; (4) developing valuation instruments that are adaptable for both chronic and acute health states, that reflect a range of severity for each health state and can be modified to reflect prognosis; (5) undertaking a full review of the DALY methodology to determine what changes may be made to reduce sources of methodological and gender bias. Despite the many criticisms of the DALY as a measurement unit, it represents a major conceptual advance since it permits the combination of life expectancy and levels of dysfunction into a single measure. Measuring reproductive ill-health by counting deaths alone is inadequate for a proper understanding of the dimensions of the problem because of the young age of many of the deaths associated with reproductive ill-health and the large component of years lived with disability from many of the associated conditions. PMID:10859859

AbouZahr, C.; Vaughan, J. P.

2000-01-01

279

Effect of chlorella and its fractions on blood pressure, cerebral stroke lesions, and life-span in stroke-prone spontaneously hypertensive rats.  

PubMed

Effects of Chlorella regularis (dried cell powder)--cultured axenically under heterotrophic conditions, and provided as a dietary supplement--and its fractions on the blood pressure, cerebral stroke lesions, and life-span of stroke-prone spontaneously hypertensive rats (SHRSP/Izm) were investigated. When SHRSP were fed on diets with supplemented Chlorella to a commercial diet (Funabashi SP), elevation of blood pressure was significantly lower in the Chlorella groups than in the control group. At 21 wk of feeding, serum total cholesterol was significantly lower in the Chlorella groups than in the control group. Histopathological examination revealed cerebral vascular accidents in the brains of the control group, but those of Chlorella groups showed apparently low incidence compared to the control group. The average life-span of the Chlorella groups were significantly longer than that of the control group (p < 0.001). Chlorella powder was fractionated into three fractions, lipid-soluble, hot water-soluble, and residual fractions. The diets supplemented with lipid or residual fractions equivalent to 10% Chlorella significantly suppressed elevation of blood pressure in SHRSP, and then decreased the incidence rate of cerebral vessel lesions compared to the control group. Chemical analysis revealed that the lipid fraction contained large quantities of antioxidants, including carotenoids (especially lutein) and others, and phospholipids involved in aorta collagen and elastin metabolism; the residual fraction contained high concentrations of arginine, enhancing the function of blood vessels. The control diet contained only a little these substances. These experimental results suggest that the beneficial effect of Chlorella on SHRSP is caused by the synergistic action of several ingredients of Chlorella, which play a role in sustention of a vascular function of rats. PMID:17330510

Sansawa, Hiroshi; Takahashi, Masatoshi; Tsuchikura, Satoru; Endo, Hiroshi

2006-12-01

280

Relevance of NAC-2, an Na+-coupled citrate transporter, to life span, body size and fat content in Caenorhabditis elegans.  

PubMed Central

We have cloned and functionally characterized an Na+-coupled citrate transporter from Caenorhabditis elegans (ceNAC-2). This transporter shows significant sequence homology to Drosophila Indy and the mammalian Na+-coupled citrate transporter NaCT (now known as NaC2). When heterologously expressed in a mammalian cell line or in Xenopus oocytes, the cloned ceNAC-2 mediates the Na+-coupled transport of various intermediates of the citric acid cycle. However, it transports the tricarboxylate citrate more efficiently than dicarboxylates such as succinate, a feature different from that of ceNAC-1 (formerly known as ceNaDC1) and ceNAC-3 (formerly known as ceNaDC2). The transport process is electrogenic, as evidenced from the substrate-induced inward currents in oocytes expressing the transporter under voltage-clamp conditions. Expression studies using a reporter-gene fusion method in transgenic C. elegans show that the gene is expressed in the intestinal tract, the organ responsible for not only the digestion and absorption of nutrients but also for the storage of energy in this organism. Functional knockdown of the transporter by RNAi (RNA interference) not only leads to a significant increase in life span, but also causes a significant decrease in body size and fat content. The substrates of ceNAC-2 play a critical role in metabolic energy production and in the biosynthesis of cholesterol and fatty acids. The present studies suggest that the knockdown of these metabolic functions by RNAi is linked to an extension of life span and a decrease in fat content and body size. PMID:14678010

Fei, You-Jun; Liu, Jin-Cai; Inoue, Katsuhisa; Zhuang, Lina; Miyake, Katsuya; Miyauchi, Seiji; Ganapathy, Vadivel

2004-01-01

281

Life-cycle exposure to the estrogenic mycotoxin zearalenone affects zebrafish (Danio rerio) development and reproduction.  

PubMed

Zearalenone (ZON) is one of the worldwide most common mycotoxin and exhibits estrogenic activity in the range of natural steroid estrogens. The occurrence of ZON has been reported in soil, drainage water, wastewater effluents, and rivers, but its ecotoxicological effects on fish have hardly been investigated. The consequences of continuous long-term ZON exposure, including a subsequent depuration period, as well as transgenerational effects of F0 short-term exposure on F1 generation were investigated. Effects on growth, reproduction activity, physiology, and morphology of zebrafish (Danio rerio) were examined in a 182 day live-cycle experiment. Life-long exposure to ZON for 140 days increased wet weight, body length, and condition factor of female fish at 1000 ng/L, and sex ratio was shifted toward female from 320 ng/L ZON. Only females at 1000 ng/L ZON revealed a 1.5-fold induction of plasma vitellogenin (VTG). Relative fecundity at 1000 ng/L recovered significantly during the depuration period. An increased condition factor in adult female F1 fish implies that exposure of F0 generation to 1000 ng/L ZON affected growth of F1 generation. A negative correlation between relative fecundity in the F1 generation (all groups exposed to 320 ng/L ZON) and the nominal ZON concentrations of the F0 exposure might indicate an influence of F0 exposure on reproductive performance of F1 generation. No exposure scenario affected fertility, hatch, embryo survival, and gonad morphology of zebrafish. Evaluating the environmental relevance of this data, the risk for fish to be harmed by exposure to ZON solely seems rather marginal, but ZON might contribute to the overall estrogenicity in the environment. © 2011 Wiley Periodicals, Inc. Environ Toxicol 2013. PMID:21695757

Schwartz, Patrick; Bucheli, Thomas D; Wettstein, Felix E; Burkhardt-Holm, Patricia

2013-05-01

282

Early life stress shapes female reproductive strategy through eggshell pigmentation in Japanese quail.  

PubMed

Physiological constraints on colouration have been widely reported; especially in birds, which trade-off antioxidant responses against colourful costly signals. One female extended phenotypic trait, which might also highlight important physiological trade-offs, is the pigmentation of their eggshells. In ground-nesting species, producing eggs that are visually undetectable by predators is the best camouflage strategy. However, the condition-dependence of eggshell pigmentation, and the pigments role in oxidative stress, may constrain females to trade-off between their antioxidant capacity and maximising the camouflage of their eggs when they deposit eggshell pigments. Developmental stress is one factor that influences female antioxidant capacity, and could lead to variations in eggshell pigmentation that might have crucial consequences on individual fitness if egg crypsis is compromised especially under stressful conditions. We investigated the interaction between developmental and breeding conditions with respect to eggshell pigmentation in Japanese quail. We studied 30 females that bred under both control and stressful conditions, and were exposed to pre- and/or post-natal stress, or neither. Pre- and post-natal stress independently influenced eggshell pigmentation strategies under stressful breeding conditions. Under stressful reproduction, eggshell protoporphyrin concentration and maculation were affected by pre-natal stress, whereas eggshell reflectance and biliverdin concentration were influenced by post-natal stress. These changes may reflect potential adaptive strategies shaped by developmental stress, but additional data on the benefit of egg crypsis in quail, combined with studies on the role of both pigments on chick survival, will help to clarify whether early life stress can enhance fitness through eggshell pigmentation when developmental and reproductive environments match. PMID:25169834

Duval, Camille; Zimmer, Cédric; Mikšík, Ivan; Cassey, Phillip; Spencer, Karen A

2014-11-01

283

The role of disturbance in the evolution of life history strategies in the intertidal mussels Mytilus edulis and Mytilus californianus  

Microsoft Academic Search

The intertidal mussels Mytilus edulis and M. californianus compete for space on the west coast of North America. An analysis of differences in size, growth rate, age at first reproduction, life span, mode of reproduction, niche and habitats between these two species demonstrates that their life history strategies are different in several important ways. M. californianus is a larger, sturdier,

Thomas H. Suchanek

1981-01-01

284

A Widespread Chromosomal Inversion Polymorphism Contributes to a Major Life-History Transition, Local Adaptation, and Reproductive Isolation  

PubMed Central

The role of chromosomal inversions in adaptation and speciation is controversial. Historically, inversions were thought to contribute to these processes either by directly causing hybrid sterility or by facilitating the maintenance of co-adapted gene complexes. Because inversions suppress recombination when heterozygous, a recently proposed local adaptation mechanism predicts that they will spread if they capture alleles at multiple loci involved in divergent adaptation to contrasting environments. Many empirical studies have found inversion polymorphisms linked to putatively adaptive phenotypes or distributed along environmental clines. However, direct involvement of an inversion in local adaptation and consequent ecological reproductive isolation has not to our knowledge been demonstrated in nature. In this study, we discovered that a chromosomal inversion polymorphism is geographically widespread, and we test the extent to which it contributes to adaptation and reproductive isolation under natural field conditions. Replicated crosses between the prezygotically reproductively isolated annual and perennial ecotypes of the yellow monkeyflower, Mimulus guttatus, revealed that alternative chromosomal inversion arrangements are associated with life-history divergence over thousands of kilometers across North America. The inversion polymorphism affected adaptive flowering time divergence and other morphological traits in all replicated crosses between four pairs of annual and perennial populations. To determine if the inversion contributes to adaptation and reproductive isolation in natural populations, we conducted a novel reciprocal transplant experiment involving outbred lines, where alternative arrangements of the inversion were reciprocally introgressed into the genetic backgrounds of each ecotype. Our results demonstrate for the first time in nature the contribution of an inversion to adaptation, an annual/perennial life-history shift, and multiple reproductive isolating barriers. These results are consistent with the local adaptation mechanism being responsible for the distribution of the two inversion arrangements across the geographic range of M. guttatus and that locally adaptive inversion effects contribute directly to reproductive isolation. Such a mechanism may be partially responsible for the observation that closely related species often differ by multiple chromosomal rearrangements. PMID:20927411

Lowry, David B.; Willis, John H.

2010-01-01

285

Marker-assisted determination of the relationship between body size and reproductive success and consequences for evaluation of adaptive life histories.  

PubMed

We tested for differences in the predicted optimal ages at first maturity in brook charr (Salvelinus fontinalis) in Freshwater River, Newfoundland, when life-history data were collated based on the marker-assisted estimation of the relationship between body size and reproductive success rather than using fecundity as a surrogate for reproductive success. Jointly with capture-recapture data to estimate the growth and survival costs of reproduction, we found that weak relationships between body size and reproductive success generate selection against delayed maturation. This finding would not have held for females if the relationship between body size and fecundity had been used as a surrogate for the relationship between body size and reproductive success. This shows that predictions of optimal life histories can be qualitatively changed when using molecular markers to directly evaluate age- and/or size-specific effects of body size on reproductive success. PMID:19765223

Morrissey, Michael B; Ferguson, Moira M

2009-10-01

286

Reproductive adaptation in Drosophila exposed to oxygen-enriched atmospheres  

NASA Technical Reports Server (NTRS)

Ten successive generations of a Drosophila melanogaster population were exposed to an atmospheric mix of 50% oxygen/50% nitrogen at standard pressure. This atmospheric mix has been shown to be toxic to this species and causes significantly shortened life span. By the fifth generation, survivorship and life span for the first 25-30 days were identical to control populations and total life span was shorter by only a few days. Egg-laying rates were stable in the experimental populations but below those of the controls. Hatching success was identical between experimental and control populations. Even though the egg-laying rates were lower in 50% oxygen, it was concluded that the population had adapted and could maintain a stable population in these conditions. The near-normal life spans, normal hatching rates, and overall population stability, exhibited following five generations of adaptation, were considered sufficient to allow continued reproduction in spite of a reduced egg-laying rate.

Kloek, G.; Winkle, L.

1979-01-01

287

A Life History Trade-Off Between Flight Ability and Reproductive Behavior in Male Field Crickets ( Gryllus texensis )  

Microsoft Academic Search

Male field crickets (Gryllus texensis) that differ in flight ability incur a life history trade-off between flight ability and reproduction, where flight ability\\u000a comes with a male fitness cost. In courtship trials, flight-capable males produced courtship song, a necessary signal for\\u000a mating success, with a significantly lower probability than flight-incapable males. The trade-off was evident in young males,\\u000a and a

Patrick A. Guerra; Gerald S. Pollack

2007-01-01

288

Reproduction, survival, and life table parameters of the predatory mite Cheyletus malaccensis (Acari: Cheyletidae) at various constant temperatures  

Microsoft Academic Search

Reproduction, survival, and life table parameters of the predatory mite Cheyletus malaccensis Oudemans were evaluated at six constant temperatures: 17.5, 20, 25, 30, 32.5 and 35°C, feeding on Tyrophagus putrescentiae (Schrank). Preoviposition period of fertilized and virgin females varied with temperature from ca. 9 days at 17.5°C to ca.\\u000a 1.5 day at 32.5°C and then increased to ca. 3 days at 35°C. Virgin

Nickolas E. PalyvosNickolas; Nickolas G. Emmanouel

2011-01-01

289

The control processes and subjective well-being of Chinese teachers: evidence of convergence with and divergence from the key propositions of the motivational theory of life-span development  

PubMed Central

An analytical review of the motivational theory of life-span development reveals that this theory has undergone a series of elegant theoretical integrations. Its claim to universality nonetheless brings forth unresolved controversies. With the purpose of scrutinizing the key propositions of this theory, an empirical study was designed to examine the control processes and subjective well-being of Chinese teachers (N = 637). The OPS-Scales (Optimization in Primary and Secondary Control Scales) for the Domain of Teaching were constructed to assess patterns of control processes. Three facets of subjective well-being were investigated with the Positive and Negative Affect Schedule, the Life Satisfaction Scale, and the Subjective Vitality Scale. The results revealed certain aspects of alignment with and certain divergences from the key propositions of the motivational theory of life-span development. Neither “primacy of primary control” nor “primacy of secondary control” was clearly supported. Notably, using different criteria for subjective well-being yielded different subtypes of primary and secondary control as predictors. The hypothesized life-span trajectories of primary and secondary control received limited support. To advance the theory in this area, we recommend incorporating Lakatos' ideas about sophisticated falsification by specifying the hard core of the motivational theory of life-span development and articulating new auxiliary hypotheses. PMID:24904483

Wong, Wan-chi; Li, Yin; Sun, Xiaoyan; Xu, Huanu

2014-01-01

290

LIFE HISTORY OF THE LONG-LIVED GYNODIOECIOUS CUSHION PLANT SILENE ACAULIS (CARYOPHYLLACEAE), INFERRED FROM SIZE-BASED POPULATION PROJECTION MATRICES1  

Microsoft Academic Search

Alpine plants often appear to have long life-spans as an adaptation to harsh and unpredictable environmental conditions, yet many lack reliable indicators of age that would make it possible to determine their true longevity. Their extended life- spans also pose problems for measuring lifetime reproductive success, a key component of breeding system evolution in species such as the gynodioecious cushion

WILLIAM F. M ORRIS; DANIEL F. D OAK

291

Life span in online communities.  

PubMed

Recently online communities have attracted great interest and have become an important medium of information exchange between users. The aim of this work is to introduce a simple model of the evolution of online communities. This model describes (a) the time evolution of users' activity in a web service, e.g., the time evolution of the number of online friends or written posts, (b) the time evolution of the degree distribution of a social network, and (c) the time evolution of the number of active users of a web service. In the second part of the paper we investigate the influence of the users' lifespan (i.e., the total time in which they are active in an online community) on the process of rumor propagation in evolving social networks. Viral marketing is an important application of such method of information propagation. PMID:21230706

Grabowski, A; Kosi?ski, R A

2010-12-01

292

Life span in online communities  

NASA Astrophysics Data System (ADS)

Recently online communities have attracted great interest and have become an important medium of information exchange between users. The aim of this work is to introduce a simple model of the evolution of online communities. This model describes (a) the time evolution of users’ activity in a web service, e.g., the time evolution of the number of online friends or written posts, (b) the time evolution of the degree distribution of a social network, and (c) the time evolution of the number of active users of a web service. In the second part of the paper we investigate the influence of the users’ lifespan (i.e., the total time in which they are active in an online community) on the process of rumor propagation in evolving social networks. Viral marketing is an important application of such method of information propagation.

Grabowski, A.; Kosi?ski, R. A.

2010-12-01

293

Early Life Exposure to Endocrine-Disrupting Chemicals Causes Lifelong Molecular Reprogramming of the Hypothalamus and Premature Reproductive Aging  

PubMed Central

Gestational exposure to the estrogenic endocrine disruptor methoxychlor (MXC) disrupts the female reproductive system at the molecular, physiological, and behavioral levels in adulthood. The current study addressed whether perinatal exposure to endocrine disruptors reprograms expression of a suite of genes expressed in the hypothalamus that control reproductive function and related these molecular changes to premature reproductive aging. Fischer rats were exposed daily for 12 consecutive days to vehicle (dimethylsulfoxide), estradiol benzoate (EB) (1 mg/kg), and MXC (low dose, 20 ?g/kg or high dose, 100 mg/kg), beginning on embryonic d 19 through postnatal d 7. The perinatally exposed females were aged to 16–17 months and monitored for reproductive senescence. After euthanasia, hypothalamic regions [preoptic area (POA) and medial basal hypothalamus] were dissected for real-time PCR of gene expression or pyrosequencing to assess DNA methylation of the Esr1 gene. Using a 48-gene PCR platform, two genes (Kiss1 and Esr1) were significantly different in the POA of endocrine-disrupting chemical-exposed rats compared with vehicle-exposed rats after Bonferroni correction. Fifteen POA genes were up-regulated by at least 50% in EB or high-dose MXC compared with vehicle. To understand the epigenetic basis of the increased Esr1 gene expression, we performed bisulfite conversion and pyrosequencing of the Esr1 promoter. EB-treated rats had significantly higher percentage of methylation at three CpG sites in the Esr1 promoter compared with control rats. Together with these molecular effects, perinatal MXC and EB altered estrous cyclicity and advanced reproductive senescence. Thus, early life exposure to endocrine disruptors has lifelong effects on neuroendocrine gene expression and DNA methylation, together with causing the advancement of reproductive senescence. PMID:22016562

Walker, Deena M.; Zama, Aparna M.; Armenti, AnnMarie E.; Uzumcu, Mehmet

2011-01-01

294

Early life exposure to endocrine-disrupting chemicals causes lifelong molecular reprogramming of the hypothalamus and premature reproductive aging.  

PubMed

Gestational exposure to the estrogenic endocrine disruptor methoxychlor (MXC) disrupts the female reproductive system at the molecular, physiological, and behavioral levels in adulthood. The current study addressed whether perinatal exposure to endocrine disruptors re-programs expression of a suite of genes expressed in the hypothalamus that control reproductive function and related these molecular changes to premature reproductive aging. Fischer rats were exposed daily for 12 consecutive days to vehicle (dimethylsulfoxide), estradiol benzoate (EB) (1 mg/kg), and MXC (low dose, 20 ?g/kg or high dose, 100 mg/kg), beginning on embryonic d 19 through postnatal d 7. The perinatally exposed females were aged to 16-17 months and monitored for reproductive senescence. After euthanasia, hypothalamic regions [preoptic area (POA) and medial basal hypothalamus] were dissected for real-time PCR of gene expression or pyrosequencing to assess DNA methylation of the Esr1 gene. Using a 48-gene PCR platform, two genes (Kiss1 and Esr1) were significantly different in the POA of endocrine-disrupting chemical-exposed rats compared with vehicle-exposed rats after Bonferroni correction. Fifteen POA genes were up-regulated by at least 50% in EB or high-dose MXC compared with vehicle. To understand the epigenetic basis of the increased Esr1 gene expression, we performed bisulfite conversion and pyrosequencing of the Esr1 promoter. EB-treated rats had significantly higher percentage of methylation at three CpG sites in the Esr1 promoter compared with control rats. Together with these molecular effects, perinatal MXC and EB altered estrous cyclicity and advanced reproductive senescence. Thus, early life exposure to endocrine disruptors has lifelong effects on neuroendocrine gene expression and DNA methylation, together with causing the advancement of reproductive senescence. PMID:22016562

Gore, Andrea C; Walker, Deena M; Zama, Aparna M; Armenti, AnnMarie E; Uzumcu, Mehmet

2011-12-01

295

Gene Pathways That Delay Caenorhabditis elegans Reproductive Senescence  

PubMed Central

Reproductive senescence is a hallmark of aging. The molecular mechanisms regulating reproductive senescence and its association with the aging of somatic cells remain poorly understood. From a full genome RNA interference (RNAi) screen, we identified 32 Caenorhabditis elegans gene inactivations that delay reproductive senescence and extend reproductive lifespan. We found that many of these gene inactivations interact with insulin/IGF-1 and/or TGF-? endocrine signaling pathways to regulate reproductive senescence, except nhx-2 and sgk-1 that modulate sodium reabsorption. Of these 32 gene inactivations, we also found that 19 increase reproductive lifespan through their effects on oocyte activities, 8 of them coordinate oocyte and sperm functions to extend reproductive lifespan, and 5 of them can induce sperm humoral response to promote reproductive longevity. Furthermore, we examined the effects of these reproductive aging regulators on somatic aging. We found that 5 of these gene inactivations prolong organismal lifespan, and 20 of them increase healthy life expectancy of an organism without altering total life span. These studies provide a systemic view on the genetic regulation of reproductive senescence and its intersection with organism longevity. The majority of these newly identified genes are conserved, and may provide new insights into age-associated reproductive senescence during human aging. PMID:25474471

Wang, Meng C.; Oakley, Holly D.; Carr, Christopher E.; Sowa, Jessica N.; Ruvkun, Gary

2014-01-01

296

Life history plasticity after attaining a dietary threshold for reproduction is associated with protein storage in flesh flies  

PubMed Central

Summary Body condition affects the timing and magnitude of life history transitions. Therefore, identifying proximate mechanisms involved in assessing condition is critical to understanding how these mechanisms affect the expression of life history plasticity. Nutrient storage is an important body condition parameter, likely playing roles in both attaining minimum body-condition thresholds for life history transitions and expression of life history traits. We manipulated protein availability for females of the flesh fly Sarcophaga crassipalpis to determine whether reproductive timing and output would remain plastic or become fixed. Liver was provided for 0, 2, 4, or 6 days of adult pre-reproductive development. Significantly, liver was removed after the feeding threshold had been attained and females had committed to producing a clutch. We also identified the major storage proteins and monitored their abundances, because protein stores may serve as an index of body condition and therefore may play an important role in life history transitions and plasticity. Flesh flies showed clear post-threshold plasticity in reproductive timing. Females fed protein for 2 days took ~30% longer to provision their clutch than those fed for 4 or 6 days. Observations of oogenesis showed the 2-day group expressed a different developmental program including slower egg provisioning. Protein availability also affected reproductive output. Females fed protein for 2 days produced ~20% fewer eggs than females fed 4 or 6 days. Six-day treated females provisioned larger eggs than 4-day treated females, followed by 2-day treated females with the smallest eggs. Two storage proteins were identified, LSP-1 and LSP-2. LSP-2 accumulation differed across feeding treatments. The 2- and 4-day treatment groups accumulated LSP-2 stores but depleted them during provisioning of the first clutch, whereas the 6-day group accumulated the greatest quantity of LSP-2 and had substantial LSP-2 stores remaining at the end of the clutch. This pattern of accumulation and depletion suggests that LSP-2 could play roles in both provisioning the current clutch and future clutches, making it a good candidate molecule for affecting reproductive timing and allotment. LSP-1 was not associated with post-threshold plasticity; it was carried over from larval feeding into adulthood and depleted uniformly across all feeding groups. PMID:19789714

Hahn, Daniel A.; James, Laura N.; Milne, Kathy R.; Hatle, John D.

2009-01-01

297

Increased production of mitochondrial reactive oxygen species and reduced adult life span in an insecticide-resistant strain of Anopheles gambiae  

PubMed Central

Control of the malaria vector An. gambiae is still largely obtained through chemical intervention using pyrethroids, such as permethrin. However, strains of An. gambiae that are resistant to the toxic effects of pyrethroids have become widespread in several endemic areas over the last decade. The objective of this study was to assess differences in five life-history traits (larval developmental time and the body weight, fecundity, hatch rate, and longevity of adult females) and energy metabolism between a strain of An. gambiae that is resistant to permethrin (RSP), due to knockdown resistance and enhanced metabolic detoxification, and a permethrin susceptible strain reared under laboratory conditions. We also quantified the expression levels of five antioxidant enzyme genes: GSTe3, CAT, GPXH1, SOD1, and SOD2. We found that the RSP strain had a longer developmental time than the susceptible strain. Additionally, RSP adult females had higher wet body weight and increased water and glycogen levels. Compared to permethrin susceptible females, RSP females displayed reduced metabolic rate and mitochondrial coupling efficiency and higher mitochondrial ROS production. Furthermore, despite higher levels of GSTe3 and CAT transcripts, RSP females had a shorter adult life span than susceptible females. Collectively, these results suggest that permethrin resistance alleles might affect energy metabolism, oxidative stress, and adult survival of An. gambiae. However, because the strains used in this study differ in their genetic backgrounds, the results need to be interpreted with caution and replicated in other strains in order to have significant implications for malaria transmission and vector control. PMID:24555527

Otali, Dennis; Novak, Robert J.; Wan, Wen; Bu, Su; Moellering, Douglas R.; De Luca, Maria

2014-01-01

298

Sirt1 extends life span and delays aging in mice through the regulation of Nk2 homeobox 1 in the DMH and LH  

PubMed Central

SUMMARY The mammalian Sir2 ortholog Sirt1 plays an important role in metabolic regulation. However, the role of Sirt1 in the regulation of aging and longevity is still controversial. Here we demonstrate that brain-specific Sirt1-overexpressing (BRASTO) transgenic mice show significant life span extension in both males and females, and aged BRASTO mice exhibit phenotypes consistent with a delay in aging. These phenotypes are mediated by enhanced neural activity specifically in the dorsomedial and lateral hypothalamic nuclei (DMH and LH, respectively), through increased orexin type 2 receptor (Ox2r) expression. We identified Nk2 homeobox 1 (Nkx2-1) as a novel partner of Sirt1 that upregulates Ox2r transcription and colocalizes with Sirt1 in the DMH and LH. DMH/LH-specific knockdown of Sirt1, Nkx2-1, or Ox2r and DMH-specific Sirt1 overexpression further support the role of Sirt1/Nkx2-1/Ox2r-mediated signaling for longevity-associated phenotypes. Our findings indicate the importance of DMH/LH-predominant Sirt1 activity in the regulation of aging and longevity in mammals. PMID:24011076

Satoh, Akiko; Brace, Cynthia S.; Rensing, Nick; Clifton, Paul; Wozniak, David F.; Herzog, Erik D.; Yamada, Kelvin A.; Imai, Shin-ichiro

2013-01-01

299

Long-term oral administration of the NMDA receptor antagonist memantine extends life span in spinocerebellar ataxia type 1 knock-in mice.  

PubMed

Spinocerebellar ataxia type 1 (SCA1) is a progressive neurodegenerative disease caused by extension of a CAG repeat in the Sca1gene. Although the mechanisms underlying the symptoms of SCA1 have not been determined, aberrant neuronal activation potentially contributes to the neuronal cell death characteristic of the disease. Here we examined the potential involvement of extrasynaptic N-methyl-d-aspartate receptor (NMDAR) activation in the pathogenesis of SCA1 by administering memantine, a low-affinity noncompetitive NMDAR antagonist, in SCA1 knock-in (KI) mice. In KI mice, the exon in the ataxin 1 gene is replaced with abnormally expanded 154CAG repeats. Memantine was administered orally to the SCA1 KI mice from 4 weeks of age until death. The treatment significantly attenuated body-weight loss and prolonged the life span of SCA1 KI mice. Furthermore, memantine significantly suppressed the loss of Purkinje cells in the cerebellum and motor neurons in the dorsal motor nucleus of the vagus, which are critical for motor function and parasympathetic function, respectively. These findings support the contribution of aberrant activation of extrasynaptic NMDARs to neuronal cell death in SCA1 KI mice and suggest that memantine may also have therapeutic benefits in human SCA1 patients. PMID:25725171

Iizuka, Akira; Nakamura, Kazuhiro; Hirai, Hirokazu

2015-04-10

300

Infantile onset Vanishing White Matter disease associated with a novel EIF2B5 variant, remarkably long life span, severe epilepsy, and hypopituitarism.  

PubMed

Vanishing White Matter disease (VWM) is an inherited progressive leukoencephalopathy caused by mutations in the genes EIF2B1-5, which encode for the 5 subunits of the eukaryotic initiation factor 2B (eIF2B), a regulator of protein synthesis. VWM typically presents with acute neurological decline following febrile infections or minor head trauma, and subsequent progressive neurological and cognitive regression. There is a varied clinical spectrum of VWM, with earlier onset associated with more severe phenotypes. Brain magnetic resonance imaging is usually diagnostic with diffusely abnormal white matter, progressing over time to cystic degeneration. We are reporting on a patient with infantile onset VWM associated with three heterozygous missense variants in EIF2B5, including a novel missense variant on exon 6 of EIF2B5 (D262N), as well as an interstitial duplication at 7q21.12. In addition, our case is unusual because of a severe epilepsy course, a novel clinical finding of hypopituitarism manifested by hypothyroidism and adrenal insufficiency, and a prolonged life span with current age of survival of 4 years and 11 months. © 2015 Wiley Periodicals, Inc. PMID:25758335

Woody, April L; Hsieh, David T; McIver, Harkirtin K; Thomas, Linda P; Rohena, Luis

2015-04-01

301

Reproduction and early life history of ruffe (Gymnocephalus cernuus) on the St. Louis River, a Lake Superior tributary  

USGS Publications Warehouse

Reproduction and early life history of ruffe (Gymnocephalus cernuus) was investigated during April to July in 1993 and 1994 in the St. Louis River, a western Lake Superior tributary. This study was conducted to assist fishery managers in determining possible interactions among the early life history stages of ruffe and other North American percids, and in obtaining information useful in developing control methods targeted at the early life history stages of ruffe. Ruffe had a prolonged spawning period that extended from late April to late June with peak spawning in mid to late May when water temperatures were between 12 and 14 degrees C. The majority of ruffe protolarva were captured 1 to 2 weeks after egg deposition between mid May and late June and most were captured in water 0.5-m deep. Onshore-offshore movements were not observed, but diel vertical movements of larval ruffe were observed on several occasions. The greatest chance of ballast water transport of pelagic larval ruffe is between mid May and July. Information on reproduction and early life history in this report will assist fishery managers in development of ruffe control methods, and assist Great Lakes shipping in ballast water management to prevent the spread of ruffe.

Brown, William P.; Selgeby, James H.; Collins, Hollie L.

1998-01-01

302

Viruses' Life History: Towards a Mechanistic Basis of a Trade-Off between Survival and Reproduction among Phages  

PubMed Central

Life history theory accounts for variations in many traits involved in the reproduction and survival of living organisms, by determining the constraints leading to trade-offs among these different traits. The main life history traits of phages—viruses that infect bacteria—are the multiplication rate in the host, the survivorship of virions in the external environment, and their mode of transmission. By comparing life history traits of 16 phages infecting the bacteria Escherichia coli, we show that their mortality rate is constant with time and negatively correlated to their multiplication rate in the bacterial host. Even though these viruses do not age, this result is in line with the trade-off between survival and reproduction previously observed in numerous aging organisms. Furthermore, a multiple regression shows that the combined effects of two physical parameters, namely, the capsid thickness and the density of the packaged genome, account for 82% of the variation in the mortality rate. The correlations between life history traits and physical characteristics of virions may provide a mechanistic explanation of this trade-off. The fact that this trade-off is present in this very simple biological situation suggests that it might be a fundamental property of evolving entities produced under constraints. Moreover, such a positive correlation between mortality and multiplication reveals an underexplored trade-off in host–parasite interactions. PMID:16756387

De Paepe, Marianne

2006-01-01

303

Latitudinal variation in life-cycle characteristics of Potamogeton pectinatus L.: vegetative growth and asexual reproduction  

Microsoft Academic Search

Across latitudinal gradients, environmental conditions that influenceplant growth and reproduction largely change. Here we study clonal variation inlife-cycle characteristics of the cosmopolitan water plantPotamogetonpectinatus L. across a broad latitudinal range.Two consecutive experiments were performed under standardised laboratoryconditions (photoperiod, irradiance and temperature). In the first experimentweinvestigated asexual reproduction among fifteen clones, obtained from latitudesranging from 24 to 68° N. After 90

Jörn Pilon; Luis Santamaría; Michiel Hootsmans; Wim van Vierssen

2003-01-01

304

Perceived risk of predation affects reproductive life-history traits in Gambusia holbrooki, but not in Heterandria formosa.  

PubMed

Key to predicting impacts of predation is understanding the mechanisms through which predators impact prey populations. While consumptive effects are well-known, non-consumptive predator effects (risk effects) are increasingly being recognized as important. Studies of risk effects, however, have focused largely on how trade-offs between food and safety affect fitness. Less documented, and appreciated, is the potential for predator presence to directly suppress prey reproduction and affect life-history characteristics. For the first time, we tested the effects of visual predator cues on reproduction of two prey species with different reproductive modes, lecithotrophy (i.e. embryonic development primarily fueled by yolk) and matrotrophy (i.e. energy for embryonic development directly supplied by the mother to the embryo through a vascular connection). Predation risk suppressed reproduction in the lecithotrophic prey (Gambusia holbrokii) but not the matrotroph (Heterandria formosa). Predator stress caused G. holbrooki to reduce clutch size by 43%, and to produce larger and heavier offspring compared to control females. H. formosa, however, did not show any such difference. In G. holbrooki we also found a significantly high percentage (14%) of stillbirths in predator-exposed treatments compared to controls (2%). To the best of our knowledge, this is the first direct empirical evidence of predation stress affecting stillbirths in prey. Our results suggest that matrotrophy, superfetation (clutch overlap), or both decrease the sensitivity of mothers to environmental fluctuation in resource (food) and stress (predation risk) levels compared to lecithotrophy. These mechanisms should be considered both when modeling consequences of perceived risk of predation on prey-predator population dynamics and when seeking to understand the evolution of reproductive modes. PMID:24551171

Mukherjee, Shomen; Heithaus, Michael R; Trexler, Joel C; Ray-Mukherjee, Jayanti; Vaudo, Jeremy

2014-01-01

305

Perceived Risk of Predation Affects Reproductive Life-History Traits in Gambusia holbrooki, but Not in Heterandria formosa  

PubMed Central

Key to predicting impacts of predation is understanding the mechanisms through which predators impact prey populations. While consumptive effects are well-known, non-consumptive predator effects (risk effects) are increasingly being recognized as important. Studies of risk effects, however, have focused largely on how trade-offs between food and safety affect fitness. Less documented, and appreciated, is the potential for predator presence to directly suppress prey reproduction and affect life-history characteristics. For the first time, we tested the effects of visual predator cues on reproduction of two prey species with different reproductive modes, lecithotrophy (i.e. embryonic development primarily fueled by yolk) and matrotrophy (i.e. energy for embryonic development directly supplied by the mother to the embryo through a vascular connection). Predation risk suppressed reproduction in the lecithotrophic prey (Gambusia holbrokii) but not the matrotroph (Heterandria formosa). Predator stress caused G. holbrooki to reduce clutch size by 43%, and to produce larger and heavier offspring compared to control females. H. formosa, however, did not show any such difference. In G. holbrooki we also found a significantly high percentage (14%) of stillbirths in predator-exposed treatments compared to controls (2%). To the best of our knowledge, this is the first direct empirical evidence of predation stress affecting stillbirths in prey. Our results suggest that matrotrophy, superfetation (clutch overlap), or both decrease the sensitivity of mothers to environmental fluctuation in resource (food) and stress (predation risk) levels compared to lecithotrophy. These mechanisms should be considered both when modeling consequences of perceived risk of predation on prey-predator population dynamics and when seeking to understand the evolution of reproductive modes. PMID:24551171

Mukherjee, Shomen; Heithaus, Michael R.; Trexler, Joel C.; Ray-Mukherjee, Jayanti; Vaudo, Jeremy

2014-01-01

306

Temperature-related variation in growth rate, size, maturation and life span in a marine herbivorous fish over a latitudinal gradient.  

PubMed

In ectotherms, growth rate, body size and maturation rate covary with temperature, with the direction and magnitude of variation predicted by the Temperature-Size Rule (TSR). Nutritional quality or availability of food, however, may vary over latitudinal gradients, resulting in ambiguous effects on body size and maturation rate. The Temperature-Constraint Hypothesis (TCH) predicts that marine herbivorous ectotherms are nutritionally compromised at latitudes exceeding 30°. This provides an opportunity to resolve the contrasting demographic responses of ectotherms to variation in temperature and nutritional status over latitudinal gradients. This study uses analysis of demographic rates to evaluate the predictions of the TSR in a marine herbivorous ectotherm sampled over a significant latitudinal gradient. The direction and magnitude of demographic variation was established in the marine herbivorous fish, Odax pullus (the butterfish), and compared with that of a phylogenetically related but trophically distinct species, the carnivorous Notolabrus fucicola (the banded wrasse). Both species were sampled at three locations across the length of New Zealand covering latitudes between 35°S and 49°S. Growth rate, mean size-at-age, age- and size-at-maturity, life span and abundance were estimated for each species at each location. Demographic traits of both taxa varied with latitude. Both species showed slower initial growth rates, and matured later at a larger body size at higher latitudes than populations sampled at lower latitudes. In addition, abundances increased significantly at higher latitudes in both species. These results were consistent with the TSR but not with the TCH, confirming that nutritional ecology (herbivore vs. carnivory) did not determine demographic patterns over a biologically significant latitudinal gradient. Results from this study suggest that the absence of herbivorous reef fishes from the higher latitudes of the Northern Hemisphere may not reflect a general physiological mechanism as suggested by the TCH and highlights the need to clarify the evolutionary histories of the marine biota of each hemisphere. PMID:24252150

L Trip, Elizabeth D; Clements, Kendall D; Raubenheimer, David; Choat, J Howard

2013-11-19

307

Recruitment and Retention Strategies for Minority or Poor Clinical Research Participants: Lessons From the Healthy Aging in Neighborhoods of Diversity Across the Life Span Study  

PubMed Central

Purpose of the study:?Investigating health disparities requires studies designed to recruit and retain racially and socioeconomically diverse cohorts. It is critical to address the barriers that disproportionately affect participation in clinical research by minorities and the socioeconomically disadvantaged. This study sought to identify and rectify these barriers to recruit and retain a biracial (African American and non-Hispanic White) and socioeconomically diverse cohort for a longitudinal study.?Design and Method:?The Healthy Aging in Neighborhoods of Diversity across the Life Span study is a 20-year longitudinal examination of how race and socioeconomic status influence the development of age-related health disparities. One goal was to create a multifactorial recruitment and retention strategy. The recruitment paradigm targeted known barriers and identified those unique to the study's urban environment. The retention paradigm mirrored the recruitment plan but was based on specifically developed approaches.?Results:?This cohort recruitment required attention to developing community partnerships, designing the research study to meet the study hypotheses and to provide benefit to participants, providing a safe community-based site for the research and creating didactics to develop staff cultural proficiency. These efforts facilitated study implementation and enhanced recruitment resulting in accrual of a biracial and socioeconomically diverse cohort of 3,722 participants.?Implications:?Recruiting and retaining minority or poor research participants is challenging but possible. The essential facets include clear communication of the research hypothesis, focus on providing a direct benefit for participants, and selection of a hypothesis that is directly relevant to the community studied PMID:21565817

Ejiogu, Ngozi; Norbeck, Jennifer H.; Mason, Marc A.; Cromwell, Bridget C.; Zonderman, Alan B.; Evans, Michele K.

2011-01-01

308

Ivermectin inhibits AMPA receptor-mediated excitotoxicity in cultured motor neurons and extends the life span of a transgenic mouse model of amyotrophic lateral sclerosis.  

PubMed

alpha-Amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptor-mediated excitotoxicity contributes to the selective motor neuron death in amyotrophic lateral sclerosis (ALS). In this study, we investigated the effect of P2 receptor-influencing substances on kainate-induced motor neuron death in an in vitro model for AMPA receptor-mediated excitotoxicity. Complete protection was found after preincubation of the motor neurons with ivermectin or Cibacron Blue 3G-A. Preincubation with both P2X4 modulators did not influence the number or Ca2+ permeability of the AMPA receptors and addition during kainate stimulation alone had no effect. Preincubation with a low concentration of ATP, the natural agonist of the P2X4 receptor, also protected the motor neurons against a subsequent excitotoxic stimulation, while high concentrations of ATP were toxic. Moreover, ivermectin increased the toxicity of low ATP concentrations, indicating that ivermectin can potentiate the effect of ATP on its receptor. Ivermectin and ATP also protected against hypoxia/hypoglycemia. To further investigate the relevance of these findings for ALS, we treated SOD1(G93A)-mice, a transgenic animal model for familial ALS, with ivermectin. This resulted in an extension of the life span of these mice with almost 10%. We conclude that ivermectin induces a mechanism in motor neurons, in vivo and in vitro, that protects against subsequent excitotoxic insults. Our in vitro data indicate that this protective mechanism is due to the potentiation by ivermectin of an effect of ATP mediated by the P2X4 receptor. PMID:17045808

Andries, Maria; Van Damme, Philip; Robberecht, Wim; Van Den Bosch, Ludo

2007-01-01

309

Potential Gains in Reproductive-Aged Life Expectancy by Eliminating Maternal Mortality: A Demographic Bonus of Achieving MDG 5  

PubMed Central

Objective We assessed the change over time in the contribution of maternal mortality to a life expectancy calculated between ages 15 and 49, or Reproductive-Aged Life Expectancy (RALE). Our goal was to estimate the increase in RALE in developed countries over the twentieth century and the hypothetical gains in African countries today by eliminating maternal mortality. Methods Analogous to life expectancy, RALE is calculated from a life table of ages 15 to 49. Specifically, RALE is the average number of years that women at age 15 would be expected to live between 15 and 49 with current mortality rates. Associated single decrement life tables of causes of death other than maternal mortality are explored to assess the possible gains in RALE by reducing or eliminating maternal mortality. We used population-based data from the Human Mortality Database and the Demographic and Health Surveys. Findings In developed countries, five years in RALE were gained over the twentieth century, of which approximately 10%, or half a year, was attributable to reductions in maternal mortality. In sub-Saharan African countries, the possible achievable gains fluctuate between 0.24 and 1.47 years, or 6% and 44% of potential gains in RALE. Conclusions Maternal mortality is a rare event, yet it is still a very important component of RALE. Averting the burden of maternal deaths could return a significant increase in the most productive ages of human life. PMID:24551040

Canudas-Romo, Vladimir; Liu, Li; Zimmerman, Linnea; Ahmed, Saifuddin; Tsui, Amy

2014-01-01

310

Life History and the Costs of Reproduction in Northern Great Plains Paddlefish (Polyodon spathula) as a Potential Framework for Other Acipenseriform Fishes  

Microsoft Academic Search

A 14-year investigation of a North American Acipenseriform fish, the paddlefish Polyodon spathula in the Yellowstone River, Montana, and North Dakota, USA has provided a detailed empirical framework of the life history in relation to the costs of reproduction for that species and potentially for closely related sturgeons. Nearly all aspects of life histories of males and females differed from

Dennis L. Scarnecchia; L. Fred Ryckman; Youngtaik Lim; Greg J. Power; Brad J. Schmitz; Jon A. Firehammer

2007-01-01

311

Life Space Over the Life Span  

Microsoft Academic Search

Much of the literature in gerontology has focused on the objective paramters of age, and the narrow causal links between behavior and environment. This has reduced the multi-layered experience of aging to stage-specific taxonomies of a disengagement process which depict behavioral units and overt operational actions, or alternately a developmental-biological paradigm that presents aging as a progressive deterioration of physical

Leon A. Pastalan; Valerie Polakow

1987-01-01

312

Seasonal trends in Ceratitis capitata reproductive potential derived from live-caught females in Greece  

PubMed Central

Reproductive data of individual insects are extremely hard to collect under natural conditions, thus the study of research questions related to oviposition has not advanced. Patterns of oviposition are often inferred only indirectly, through monitoring of host infestation, whereas the influence of age structure and several other factors on oviposition remains unknown. Using a new approach, in this article, we live-trapped wild Ceratitis capitata (Wiedemann) (Diptera: Tephritidae) females on the Greek island of Chios during two field seasons. For their remaining lifetime, these females were placed individually in small cages and their daily oviposition was monitored. Reproduction rates between cohorts from different collection dates were then compared. The results showed that in the different captive cohorts the average remaining lifetime and reproduction were highly variable within and between seasons. Multivariate regression analysis showed that the month of capture had a significant effect on captive life span, average daily reproduction, and patterns of egg laying. The effect of year was significant on reproduction, but not on captive life span. These differences between sampling periods probably reflect differences in the availability of hosts and other factors that vary during the season and affect age structure and reproduction. Using a non-parametric generalized additive model, we found a statistically significant correlation between the captive life span and the average daily reproduction. These findings and the experimental approach have several important implications. PMID:22791908

Kouloussis, Nikos A.; Papadopoulos, Nikos T.; Katsoyannos, Byron I.; Müller, Hans-Georg; Wang, Jane-Ling; Su, Yu-Ru; Molleman, Freerk; Carey, James R.

2012-01-01

313

Seasonal trends in Ceratitis capitata reproductive potential derived from live-caught females in Greece.  

PubMed

Reproductive data of individual insects are extremely hard to collect under natural conditions, thus the study of research questions related to oviposition has not advanced. Patterns of oviposition are often inferred only indirectly, through monitoring of host infestation, whereas the influence of age structure and several other factors on oviposition remains unknown. Using a new approach, in this article, we live-trapped wild Ceratitis capitata (Wiedemann) (Diptera: Tephritidae) females on the Greek island of Chios during two field seasons. For their remaining lifetime, these females were placed individually in small cages and their daily oviposition was monitored. Reproduction rates between cohorts from different collection dates were then compared. The results showed that in the different captive cohorts the average remaining lifetime and reproduction were highly variable within and between seasons. Multivariate regression analysis showed that the month of capture had a significant effect on captive life span, average daily reproduction, and patterns of egg laying. The effect of year was significant on reproduction, but not on captive life span. These differences between sampling periods probably reflect differences in the availability of hosts and other factors that vary during the season and affect age structure and reproduction. Using a non-parametric generalized additive model, we found a statistically significant correlation between the captive life span and the average daily reproduction. These findings and the experimental approach have several important implications. PMID:22791908

Kouloussis, Nikos A; Papadopoulos, Nikos T; Katsoyannos, Byron I; Müller, Hans-Georg; Wang, Jane-Ling; Su, Yu-Ru; Molleman, Freerk; Carey, James R

2011-09-01

314

The perfume of reproduction in birds: chemosignaling in avian social life.  

PubMed

This article is part of a Special Issue "Chemosignals and Reproduction". Chemical cues were probably the first cues ever used to communicate and are still ubiquitous among living organisms. Birds have long been considered an exception: it was believed that birds were anosmic and relied on their acute visual and acoustic capabilities. Birds are however excellent smellers and use odors in various contexts including food searching, orientation, and also breeding. Successful reproduction in most vertebrates involves the exchange of complex social signals between partners. The first evidence for a role of olfaction in reproductive contexts in birds only dates back to the seventies, when ducks were shown to require a functional sense of smell to express normal sexual behaviors. Nowadays, even if the interest for olfaction in birds has largely increased, the role that bodily odors play in reproduction still remains largely understudied. The few available studies suggest that olfaction is involved in many reproductive stages. Odors have been shown to influence the choice and synchronization of partners, the choice of nest-building material or the care for the eggs and offspring. How this chemical information is translated at the physiological level mostly remains to be described, although available evidence suggests that, as in mammals, key reproductive brain areas like the medial preoptic nucleus are activated by relevant olfactory signals. Olfaction in birds receives increasing attention and novel findings are continuously published, but many exciting discoveries are still ahead of us, and could make birds one of the animal classes with the largest panel of developed senses ever described. PMID:24928570

Caro, Samuel P; Balthazart, Jacques; Bonadonna, Francesco

2015-02-01

315

Evolutionary relationships among food habit, loss of flight, and reproductive traits: life-history evolution in the Silphinae (Coleoptera: Silphidae).  

PubMed

Flightlessness in insects is generally thought to have evolved due to changes in habitat environment or habitat isolation. Loss of flight may have changed reproductive traits in insects, but very few attempts have been made to assess evolutionary relationships between flight and reproductive traits in a group of related species. We elucidated the evolutionary history of flight loss and its relationship to evolution in food habit, relative reproductive investment, and egg size in the Silphinae (Coleoptera: Silphidae). Most flight-capable species in this group feed primarily on vertebrate carcasses, whereas flightless or flight-dimorphic species feed primarily on soil invertebrates. Ancestral state reconstruction based on our newly constructed molecular phylogenetic tree implied that flight muscle degeneration occurred twice in association with food habit changes from necrophagy to predatory, suggesting that flight loss could evolve independently from changes in the environmental circumstances per se. We found that total egg production increased with flight loss. We also found that egg size increased with decreased egg number following food habit changes in the lineage leading to predaceous species, suggesting that selection for larger larvae intensified with the food habit change. This correlated evolution has shaped diverse life-history patterns among extant species of Silphinae. PMID:18507741

Ikeda, Hiroshi; Kagaya, Takashi; Kubota, Kohei; Abe, Toshio

2008-08-01

316

Influence of early-life nutrition on mortality and reproductive success during a subsequent famine in a preindustrial population  

PubMed Central

Individuals with insufficient nutrition during development often experience poorer later-life health and evolutionary fitness. The Predictive Adaptive Response (PAR) hypothesis proposes that poor early-life nutrition induces physiological changes that maximize fitness in similar environments in adulthood and that metabolic diseases result when individuals experiencing poor nutrition during development subsequently encounter good nutrition in adulthood. However, although cohort studies have shown that famine exposure in utero reduces health in favorable later-life conditions, no study on humans has demonstrated the predicted fitness benefit under low later-life nutrition, leaving the evolutionary origins of such plasticity unexplored. Taking advantage of a well-documented famine and unique datasets of individual life histories and crop yields from two preindustrial Finnish populations, we provide a test of key predictions of the PAR hypothesis. Known individuals from fifty cohorts were followed from birth until the famine, where we analyzed their survival and reproductive success in relation to the crop yields around birth. We were also able to test whether the long-term effects of early-life nutrition differed between individuals of varying socioeconomic status. We found that, contrary to predictions of the PAR hypothesis, individuals experiencing low early-life crop yields showed lower survival and fertility during the famine than individuals experiencing high early-life crop yields. These effects were more pronounced among young individuals and those of low socioeconomic status. Our results do not support the hypothesis that PARs should have been favored by natural selection and suggest that alternative models may need to be invoked to explain the epidemiology of metabolic diseases. PMID:23918366

Hayward, Adam D.; Rickard, Ian J.; Lummaa, Virpi

2013-01-01

317

Life in bromeliads: reproductive behaviour and the monophyly of the Scinax perpusillus species group (Anura: Hylidae)  

Microsoft Academic Search

Several aspects of the reproductive behaviour of species of the Scinax perpusillus group (S. perpusillus, S. v?signatus, S. littoreus, and three other not yet described species) obtained from direct field observations and nocturnal video filming are presented and evaluated. Males of the observed species have behavioural characters, including aspects of their call, that are indicative of territory defence. Vocalizations are

Hélio Ricardo da Silva

2009-01-01

318

EFFECTS OF SUSPENDED SOLIDS AND SEDIMENT ON REPRODUCTION AND EARLY LIFE OF WARMWATER FISHES: A REVIEW  

EPA Science Inventory

The review of published literature and research reports revealed limited data for a few warmwater fish species concerning the impacts of suspended solids and sediments on reproductive success. Laboratory and field studies during the 1930-50s examined direct mortality as the resul...

319

Reproduction in high altitude Aymara: physiological stress and fertility planning?  

PubMed

Reproductive characteristics at high altitude are described based on the reproductive histories of 720 Aymara women, collected in 1998 and 1999 in a group of twelve peasant communities at a mean altitude of 4000 m in the Bolivian Altiplano. The reproductive pattern is shaped by a late onset of childbearing, associated with a rather short reproductive span and large birth intervals. Environmental conditions could explain the particularly late age at menarche of rural girls compared with their urban counterparts, whereas the age at first birth is likely to be under cultural control. The short reproductive span appears to result from a large mean interval between last birth and menopause, which is essentially determined by cultural decisions. The birth intervals, which are longer than in many traditional societies, could be the result of a slower restoration of postpartum fecundability induced by the hard way of life inherent in the Altiplano (including poor sanitary and nutritional conditions and high workload), perhaps aggravated by hypoxia. However, a secular trend in fertility is perceptible, towards earlier menarche, earlier age at first birth, increasing reproductive span and a slight increase in live births and surviving offspring, which is probably the result of a slow improvement in living conditions. The existence of birth control on the one hand, and a total fertility rate averaging six live births among the couples who do not practise contraception on the other, are other arguments against the hypothesis of a low natural fecundity in these Aymara groups. PMID:12395863

Crognier, E; Villena, M; Vargas, E

2002-10-01

320

Reproduction & life I. Reproductive cycles  

E-print Network

cohort of oocytes each year l Vitellogenesis ­ nutrient accumulation in ovum l As ova pass through oviduct, protective membranes form around them Reptiles- ovum is encased w/shell Ova energetically more

Dever, Jennifer A.

321

PLASTICITY AND CANALIZATION OF INSECT REPRODUCTION: TESTING ALTERNATIVE MODELS OF LIFE HISTORY TRANSITIONS  

Microsoft Academic Search

Life histories may show phases of both plasticity and canalization in response to feeding rate. Models for life history canalization and plasticity postulate a threshold for initiation of canalized developmental events. Some models postulate adaptive plasticity, whereas others postulate nonadaptive plasticity that results from environmental modulation of fixed development. These models have been tested by changing feeding rate at various

Steven A. Juliano; Jennifer R. Olson; Ebony G. Murrell; John D. Hatle

2004-01-01

322

Selective Reproduction: Social and Temporal Imaginaries for Negotiating the Value of Life in Human and Animal Neonates.  

PubMed

This article employs a multi-species perspective in investigating how life's worth is negotiated in the field of neonatology in Denmark. It does so by comparing decision-making processes about human infants in the Danish neonatal intensive care unit with those associated with piglets who serve as models for the premature infants in research experiments within neonatology. While the comparison is unusual, the article argues that there are parallels across the decision-making processes that shape the lives and deaths of infants and pigs alike. Collectivities or the lack thereof as well as expectations within linear or predictive time frames are key markers in both sites. Exploring selective reproductive processes across human infants and research piglets can help us uncover aspects of the cultural production of viability that we would not otherwise see or acknowledge. PMID:25359420

Svendsen, Mette N

2014-10-31

323

3. VIEW NORTH SHOWING FIXED SPAN, COVERED SPAN, MOVEABLE TRANSITION ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

3. VIEW NORTH SHOWING FIXED SPAN, COVERED SPAN, MOVEABLE TRANSITION SPAN AND PONTOON FLOATING SPAN - Lacey V. Murrow Memorial Floating Bridge, Spanning Lake Washington at I-90, Seattle, King County, WA

324

Reproductive success in presenescent common gulls (Larus canus): the importance of the last year of life.  

PubMed

Survival selection against individuals of inferior quality (measured as breeding success) has been proposed to account for the increase in average reproductive success with advancing age in presenescent birds. This so-called selection hypothesis relies on quality-dependent survival. In the present breeding performance study of common gulls, Larus canus, this assumption was not verified. In particular, omitting the last breeding year from the analysis resulted in the disappearance of the correlation between breeding success and survival. A positive correlation in the full dataset was thus solely based on the poor breeding success of ultimate breeders. Indeed, presenescent individuals were shown to have a specifically low breeding success in their terminal breeding event. The poor success of ultimate breeders thus reflects an abruptly declined condition rather than the birds' overall quality. A comparison of the survival of poor and good performers, involving last-time breeders, thus needs not to be a proper test of the selection hypothesis. Longitudinal analysis revealed a steady increase of individual breeding success until the tenth breeding year. The results suggest that an increase of breeding success with age often found in cross-sectional analyses is primarily a result of age-related improvements of competence and/or increased reproductive effort. PMID:15451696

Rattiste, Kalev

2004-10-01

325

Reproductive success in presenescent common gulls (Larus canus): the importance of the last year of life.  

PubMed Central

Survival selection against individuals of inferior quality (measured as breeding success) has been proposed to account for the increase in average reproductive success with advancing age in presenescent birds. This so-called selection hypothesis relies on quality-dependent survival. In the present breeding performance study of common gulls, Larus canus, this assumption was not verified. In particular, omitting the last breeding year from the analysis resulted in the disappearance of the correlation between breeding success and survival. A positive correlation in the full dataset was thus solely based on the poor breeding success of ultimate breeders. Indeed, presenescent individuals were shown to have a specifically low breeding success in their terminal breeding event. The poor success of ultimate breeders thus reflects an abruptly declined condition rather than the birds' overall quality. A comparison of the survival of poor and good performers, involving last-time breeders, thus needs not to be a proper test of the selection hypothesis. Longitudinal analysis revealed a steady increase of individual breeding success until the tenth breeding year. The results suggest that an increase of breeding success with age often found in cross-sectional analyses is primarily a result of age-related improvements of competence and/or increased reproductive effort. PMID:15451696

Rattiste, Kalev

2004-01-01

326

Designing prospective cohort studies for assessing reproductive and developmental toxicity during sensitive windows of human reproduction and development--the LIFE Study.  

PubMed

The relationship between the environment and human fecundity and fertility remains virtually unstudied from a couple-based perspective in which longitudinal exposure data and biospecimens are captured across sensitive windows. In response, we completed the LIFE Study with methodology that intended to empirically evaluate a priori purported methodological challenges: implementation of population-based sampling frameworks suitable for recruiting couples planning pregnancy; obtaining environmental data across sensitive windows of reproduction and development; home-based biospecimen collection; and development of a data management system for hierarchical exposome data. We used two sampling frameworks (i.e., fish/wildlife licence registry and a direct marketing database) for 16 targeted counties with presumed environmental exposures to persistent organochlorine chemicals to recruit 501 couples planning pregnancies for prospective longitudinal follow-up while trying to conceive and throughout pregnancy. Enrolment rates varied from <1% of the targeted population (n =?424,423) to 42% of eligible couples who were successfully screened; 84% of the targeted population could not be reached, while 36% refused screening. Among enrolled couples, ? 85% completed daily journals while trying; 82% of pregnant women completed daily early pregnancy journals, and 80% completed monthly pregnancy journals. All couples provided baseline blood/urine samples; 94% of men provided one or more semen samples and 98% of women provided one or more saliva samples. Women successfully used urinary fertility monitors for identifying ovulation and home pregnancy test kits. Couples can be recruited for preconception cohorts and will comply with intensive data collection across sensitive windows. However, appropriately sized sampling frameworks are critical, given the small percentage of couples contacted found eligible and reportedly planning pregnancy at any point in time. PMID:21819423

Buck Louis, Germaine M; Schisterman, Enrique F; Sweeney, Anne M; Wilcosky, Timothy C; Gore-Langton, Robert E; Lynch, Courtney D; Boyd Barr, Dana; Schrader, Steven M; Kim, Sungduk; Chen, Zhen; Sundaram, Rajeshwari

2011-09-01

327

Minimum Spanning Tree Jayadev Misra  

E-print Network

Minimum Spanning Tree Jayadev Misra 12/12/98 1 Spanning Tree A spanning tree of an undirected graph for finding the minimum spanning tree. Properties of spanning trees In a spanning tree: · There is no cycle edges have non-negative weights. A minimum span- ning tree is a spanning tree whose total edge weight

Misra, Jayadev

328

View of central lift span truss web of Tensaw River ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

View of central lift span truss web of Tensaw River Bridge, showing support girders for life house, looking east - Tensaw River Lift Bridge, Spanning Tensaw River at U.S. Highway 90, Mobile, Mobile County, AL

329

Bioscience-bioethics and life factors affecting reproduction with special reference to the Indigenous Australian population.  

PubMed

The demand for equality of recognition or respect is the dominant passion of modernity. The 20th century experienced a giant leap in technological inventiveness and ruthless use of technological power. In the 21st century, human welfare and environmental wellbeing demand fundamental political appraisal. We have the means, if we choose, to eradicate poverty and to responsibly protect the global environment. However, economic, political and cultural systems act to differentially allocate the benefits and risks for growth between socioeconomic groups. For example, it is a matter of pride that the neonatal mortality rate in affluent societies has dropped substantially since the late 1970s. However, the level of infant mortality (three times the national average) and low birthweight (13%) among the Indigenous Australian population is the highest in the country. With hindsight we now know that is the inevitable legacy of Australia's colonial history. Chronic physical and psychological stress is recognized as an important etiological factor in many lifestyle diseases of the cardiovascular, immune and reproductive systems. Diseases of adaptation are further advanced by non-adaptive lifestyle choices, depression, alcoholism and other drug dependencies. This review describes the principles of bioscience ethics and targets equity issues as they affect human reproduction across generations with particular reference to the Indigenous population of Australia. The review also considers ways we may advance global and cultural maturity from the Indigenous Australian perspective and proposes an ecologically based model of preventative care. If we are to embrace fundamental social change and protect future children without threatening parents' basic freedoms, then new beliefs and priorities--based on a compassionate understanding of biological systems--must evolve from the general public. Belief in human rights arising from a sense of human dignity is a collective outcome originating from individual commitment. The golden rule; that is, Nature's principle of reciprocity, is fundamental in bridging the gap between knowledge and effective action. PMID:15798014

Pollard, Irina

2005-04-01

330

SPAN: Ocean science  

NASA Technical Reports Server (NTRS)

The Space Physics Analysis Network (SPAN) is a multi-mission, correlative data comparison network which links space and Earth science research and data analysis computers. It provides a common working environment for sharing computer resources, sharing computer peripherals, solving proprietary problems, and providing the potential for significant time and cost savings for correlative data analysis. This is one of a series of discipline-specific SPAN documents which are intended to complement the SPAN primer and SPAN Management documents. Their purpose is to provide the discipline scientists with a comprehensive set of documents to assist in the use of SPAN for discipline specific scientific research.

Thomas, Valerie L.; Koblinsky, Chester J.; Webster, Ferris; Zlotnicki, Victor; Green, James L.

1987-01-01

331

Japan turns pro-life: recent change in reproductive health policy and challenges by new technologies  

PubMed Central

Japan, known as a pro-choice country in terms of abortion, is currently facing the increase of “selective abortions” thanks to new prenatal screening. Efforts to restrict proliferation of new technology has not been successful and it is likely that Japan will turn pro-life by strictly enforcing the Maternity Protection Act (MPA), which prohibits abortions due to “fetal cause”. PMID:24639978

Okamoto, Etsuji

2014-01-01

332

On the Life History of Planktonic Foraminifera: Lunar Reproduction Cycle in Globigerinoides Sacculifer (Brady)  

Microsoft Academic Search

Detailed plankton sampling in the Gulf of Elat, Red Sea, demonstrates a lunar periodicity in the abundance of the foraminifer Globigerinoides sacculifer in surface water as well as below the photic zone. Shell size distribution coupled with abundance changes and laboratory observations suggests the following scheme for the life cycle of this spinose foraminifer: Young individuals of roughly 200 µm

Jonathan Erez; Ahuva Almogi-Labin; Sophie Avraham

1991-01-01

333

Multiple paternity, male reproductive success, hormonal regulation of fertility, and the evolution of life-histories  

Microsoft Academic Search

The life-history strategy that an individual exhibits is shaped by trade-offs between maximizing the number of viable offspring it produces and retaining enough resources to ensure its own survival. The balance between these two aspects is strongly influenced by the environmental conditions the individual experiences in its lifetime and can be affected by the effort an individual puts into each

Megan Brianne Manes

2011-01-01

334

Reproductive styles and life history variables relative to exploitation and management of Sebastes stocks  

Microsoft Academic Search

Synopsis  The characteristics of lightly and heavily exploited Pacific ocean perch,Sebastes alutus, stocks are evaluated relative to the predictions of life history theory. These long-lived species (50–100 year lifespan)\\u000a show limited phenotypic plasticity and have little buffering against the effects of reduced lifespan. Reduced stock abundance\\u000a has generated some compensatory increase in growth rate. Length at first maturity varies only slightly

Bruce M. Leaman

1991-01-01

335

Life history of yellow baboons: Physical development, reproductive parameters, and infant mortality  

Microsoft Academic Search

Longitudinal data from a population of yellow baboons,Papio cynocephalus, in the Amboseli National Park, Kenya, provide life history parameter estimates. Females reached menarche at approximately\\u000a four-and-a-half years of age and then cycled for approximately a year before first conception. Postpartum anestrum averaged\\u000a 12 months but ranged from six to 16 months. In cases of still births or infant death during

Jeanne Altmann; Stuart A. Altmann; Glenn Hausfater; Sue Ann McCuskey

1977-01-01

336

Life history of hamadryas baboons: Physical development, infant mortality, reproductive parameters and family relationships  

Microsoft Academic Search

Demographic and life history parameters were estimated for a band of free-ranging hamadryas baboons, observed for 5.5 years\\u000a in Ethiopia. Age-related changes in body weight and dentition were found to be delayed relative to laboratory-reared baboons.\\u000a On the average, females reached menarche at 4.3 years of age and had their first infant at the age of 6.1 years. The mean

H. Sigg; A. Stolba; J.-J. Abegglen; V. Dasser

1982-01-01

337

The Years of Uncertainty: Eighth Grade Family Life Education.  

ERIC Educational Resources Information Center

The family life sex education unit for eighth graders, "The Years of Uncertainty," consists of a series of daily lesson plans that span a 29-day period of one-hour class sessions. Topics covered are: problem solving, knowledge and attitudes, male and female reproductive systems, conception, pregnancy, birth, birth defects, venereal disease,…

Carson, Mary, Ed.; And Others

338

Insulin-like growth factor-I extends in vitro replicative life span of skeletal muscle satellite cells by enhancing G1/S cell cycle progression via the activation of phosphatidylinositol 3'-kinase/Akt signaling pathway  

NASA Technical Reports Server (NTRS)

Interest is growing in methods to extend replicative life span of non-immortalized stem cells. Using the insulin-like growth factor I (IGF-I) transgenic mouse in which the IGF-I transgene is expressed during skeletal muscle development and maturation prior to isolation and during culture of satellite cells (the myogenic stem cells of mature skeletal muscle fibers) as a model system, we elucidated the underlying molecular mechanisms of IGF-I-mediated enhancement of proliferative potential of these cells. Satellite cells from IGF-I transgenic muscles achieved at least five additional population doublings above the maximum that was attained by wild type satellite cells. This IGF-I-induced increase in proliferative potential was mediated via activation of the phosphatidylinositol 3'-kinase/Akt pathway, independent of mitogen-activated protein kinase activity, facilitating G(1)/S cell cycle progression via a down-regulation of p27(Kip1). Adenovirally mediated ectopic overexpression of p27(Kip1) in exponentially growing IGF-I transgenic satellite cells reversed the increase in cyclin E-cdk2 kinase activity, pRb phosphorylation, and cyclin A protein abundance, thereby implicating an important role for p27(Kip1) in promoting satellite cell senescence. These observations provide a more complete dissection of molecular events by which increased local expression of a growth factor in mature skeletal muscle fibers extends replicative life span of primary stem cells than previously known.

Chakravarthy, M. V.; Abraha, T. W.; Schwartz, R. J.; Fiorotto, M. L.; Booth, F. W.

2000-01-01

339

The influence of the hot water extract from shiitake medicinal mushroom, Lentinus edodes (higher Basidiomycetes) on the food intake, life span, and age-related locomotor activity of Drosophila melanogaster.  

PubMed

Shiitake medicinal mushroom, Lentinus edodes, is among the most widely cultivated edible mushrooms in the world and is a well-studied source of nutrients and biologically active compounds. We have studied the influence of the dietary supplement of the polysaccharides containing a hot water extract of the mushroom L. edodes on the fruit fly Drosophila melanogaster in terms of food intake, body weight, life span, and age-related locomotor activity. L. edodes extract, when added to the D. melanogaster feeding substrate at a 0.003-0.030% concentration (calculated for the dry weight of the polysaccharide fraction) did not influence food intake or body weight of the flies. It increased the life span and locomotor activities of male flies but was associated with early mortality and decreased locomotor activity of female flies. We conclude that the observed anti-aging effects of L. edodes extracts in the male D. melanogaster are not the result of dietary restriction. We propose that D. melanogaster is a suitable model organism for researching the molecular basis of the anti-aging effect of the shiitake mushroom extracts and sex linkage of these effects. PMID:25404225

Matjuskova, Natalya; Azena, Elena; Serstnova, Ksenija; Muiznieks, Indrikis

2014-01-01

340

REPRODUCTIVE DEVELOPMENT  

Technology Transfer Automated Retrieval System (TEKTRAN)

Throughout history, humans have celebrated the beauty and fertility of flowering plants. In addition to their aesthetic appeal, flowers contain the reproductive organs of the plant and are therefore essential for sexual propagation of plant life. Our dependence on flowering is illustrated by the die...

341

SPAN: Astronomy and astrophysics  

NASA Technical Reports Server (NTRS)

The Space Physics Analysis Network (SPAN) is a multi-mission, correlative data comparison network which links science research and data analysis computers in the U.S., Canada, and Europe. The purpose of this document is to provide Astronomy and Astrophysics scientists, currently reachable on SPAN, with basic information and contacts for access to correlative data bases, star catalogs, and other astrophysic facilities accessible over SPAN.

Thomas, Valerie L.; Green, James L.; Warren, Wayne H., Jr.; Lopez-Swafford, Brian

1987-01-01

342

4. DETAIL VIEW FIXED SPAN INCLUDING TRUSS, MOVEABLE SPAN WHICH ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

4. DETAIL VIEW FIXED SPAN INCLUDING TRUSS, MOVEABLE SPAN WHICH THE NEXT UNIT TO THE RIGHT, AND FIRST UNIT OF PONTOON FLOATING SPAN. - Lacey V. Murrow Memorial Floating Bridge, Spanning Lake Washington at I-90, Seattle, King County, WA

343

EVOLUTION OF THE ALTERNATION OF HAPLOID AND DIPLOID PHASES IN LIFE-CYCLES .2. MAINTENANCE OF THE HAPLODIPLONTIC CYCLE  

Microsoft Academic Search

The relative duration of the haploid and the diploid phases during the reproductive cycle varies greatly between organisms. This paper addresses the question of the evolution of haploid, diploid, and haplo-diplontic life cycles. When the life span of haploid and diploid individuals is constant whatever their cycle, we show that the haplo-diplontic cycle has an advantage, which depends on the

Sophie Richerd; Denis Couvet; Myriam Valero

1993-01-01

344

What Deficits in Sexual and Reproductive Health Knowledge Exist among Women with Cystic Fibrosis? A Systematic Review  

ERIC Educational Resources Information Center

The life span of patients with cystic fibrosis (CF) continues to extend due to advances in treatments and care. The rate of pregnancy for female patients with CF has also continued to rise. The purpose of this study was to systematically review the available literature on female patients with CF and their knowledge of sexual and reproductive…

Gage, L. Ashley

2012-01-01

345

The structure of a thermophilic archaeal virus shows a dsDNA viral capsid type that spans all domains of life  

SciTech Connect

Of the three domains of life (Eukarya, Bacteria, and Archaea), the least understood is Archaea and its associated viruses. Many Archaea are extremophiles, with species that are capable of growth at some of the highest temperatures and extremes of pH of all known organisms. Phylogenetic rRNA-encoding DNA analysis places many of the hyperthermophilic Archaea (species with an optimum growth >80°C) at the base of the universal tree of life, suggesting that thermophiles were among the first forms of life on earth. Very few viruses have been identified from Archaea as compared to Bacteria and Eukarya. We report here the structure of a hyperthermophilic virus isolated from an archaeal host found in hot springs in Yellowstone National Park. The sequence of the circular double-stranded DNA viral genome shows that it shares little similarity to other known genes in viruses or other organisms. By comparing the tertiary and quaternary structures of the coat protein of this virus with those of a bacterial and an animal virus, we find conformational relationships among all three, suggesting that some viruses may have a common ancestor that precedes the division into three domains of life >3 billion years ago.

G. Rice; L. Tang; K. Stedman; F. Roberto; J. Spuhler; E. Gillitzer; J. E. Johnson; T. Douglas; M. Young

2004-05-01

346

Minimum Spanning Tree What is a Minimum Spanning Tree.  

E-print Network

Minimum Spanning Tree · What is a Minimum Spanning Tree. · Constructing Minimum Spanning Trees. · What is a Minimum-Cost Spanning Tree. · Applications of Minimum Cost Spanning Trees. · Prim's Algorithm;What is a Minimum Spanning Tree. · Let G = (V, E) be a simple, connected, undirected graph

Razak, Saquib

347

Reproductive cooperation between queens and their mated workers: the complex life history of an ant with a valuable nest.  

PubMed

The life history of Harpegnathos saltator is exceptional among ants because both queens and workers reproduce sexually. Recently mated queens start new colonies alone, but later some of the offspring workers also become inseminated and take over the egg-laying role. This alternation seems associated with the existence of very complex underground nests, which are designed to survive floods. Longevity of ponerine queens is low (a consequence of limited caste dimorphism in this "primitive" subfamily), and upon the death of an H. saltator foundress, the nest represents a substantial investment. The queen's progeny should thus be strongly selected to retain the valuable nests. Unlike the flying queens, the workers copulate with males from their own colonies, and, thus, their offspring are expected to be highly related to the foundress. Colony fission appears not to occur because a daughter fragment would lack an adequate nest for protection. Thus, the annual production of queens in colonies with reproductive workers remains essential for the establishment of new colonies. This contrasts with various other ponerine species in which the queens no longer exist. PMID:11607589

Peeters, C; Hölldobler, B

1995-11-21

348

Effects of trilostane and fipronil on the reproductive axis in an early life stage of the Japanese medaka (Oryzias latipes).  

PubMed

Given the critical role of the hypothalamic-pituitary-gonadal (HPG) axis, it is conceivable that perturbations at any point along this axis can potentially affect reproduction in fish and other vertebrates. We investigated the effects of a 3?-hydroxysteroid dehydrogenase (3?-HSD) inhibitor, trilostane (TRI), and a gamma-aminobutyric acid (GABA)-receptor antagonist, fipronil (FIP), on the HPG axis using an early life stage of the Japanese medaka. The newly hatched larvae were exposed to TRI (100, 300 and 1000 ?g/L) and FIP (3, 10 and 30 ?g/L), respectively, until 28 days post-hatching. Exposure to TRI decreased the body length in males, whereas FIP inhibited growth in both sexes. The induction of steroidogenesis-regulating genes (including 3?-hsd) in males exposed to TRI, accompanied by increased vtg and er transcription, indicating a compensatory response to the presumed 3?-HSD inhibition. These compensatory responses were not observed in TRI-treated females. Regarding FIP exposure, the GABA blocker resulted in the down-regulation of fshr and lhr. A compensatory up-regulation of steroidogenesis-regulating genes partially explained the elevated transcripts of vtg genes in both males and females after FIP exposure. These results suggest that both the inhibition of 3?-HSD and the antagonism of GABA receptors are relevant modes of endocrine disruption that could impact the normal regulation of the HPG axis. PMID:24777665

Sun, Liwei; Jin, Rong; Peng, Zuhua; Zhou, Qiwei; Qian, Haifeng; Fu, Zhengwei

2014-08-01

349

Aging alterations in whole-brain networks during adulthood mapped with the minimum spanning tree indices: The interplay of density, connectivity cost and life-time trajectory.  

PubMed

The organizational network changes in the human brain across the lifespan have been mapped using functional and structural connectivity data. Brain network changes provide valuable insights into the processes underlying senescence. Nonetheless, the altered network density in the elderly severely compromises the usefulness of network analysis to study the aging brain. We successfully circumvented this problem by focusing on the critical structural network backbone, using a robust tree representation. Whole-brain networks' minimum spanning trees were determined in a dataset of diffusion-weighted images from 382 healthy subjects, ranging in age from 20.2 to 86.2years. Tree-based metrics were compared with classical network metrics. In contrast to the tree-based metrics, classical metrics were highly influenced by age-related changes in network density. Tree-based metrics showed linear and non-linear correlation across adulthood and are in close accordance with results from previous histopathological characterizations of the changes in white matter integrity in the aging brain. PMID:25585021

Otte, Willem M; van Diessen, Eric; Paul, Subhadip; Ramaswamy, Rajiv; Subramanyam Rallabandi, V P; Stam, Cornelis J; Roy, Prasun K

2015-04-01

350

Do self-referent metacognition and residential context predict depressive symptoms across late-life span? A developmental study in an Italian sample.  

PubMed

Objectives: There is controversial evidence concerning the variables favoring depression in community-dwelling elderly individuals. This study mainly investigates the impact of lifestyle, residential environment, cognitive efficiency and social desirability in predicting self-assessed depressive signs in late adult span. Method: One hundred forty-nine elders were recruited in Northern Italy and Sardinia - an Italian island characterized by the longevity of people living in the inner areas. Participants were presented a battery of questionnaires assessing cognitive efficiency and self-referent measures of depression, metacognition and social desirability. Results: A hierarchical regression analysis showed that residential environment was the most effective predictor of depressive symptoms, along with gardening and spending time for hobbies. In contrast, social desirability and metacognitive scores played a minor role in predicting mental health. An analysis of variance showed that Sardinian elders showed fewer signs of depression than age-matched elders residing in Northern Italy. Conclusion: The Sardinian residential environment is a strong predictor of preserved mental health in late adulthood. In contrast, self-rated metacognitive efficiency and social desirability play a very marginal role in predicting depression among the elderly. PMID:25255033

Fastame, Maria Chiara; Hitchcott, Paul Kenneth; Penna, Maria Pietronilla

2014-09-25

351

Integrating life-history and reproductive success data to examine potential relationships with organochlorine compounds for bottlenose dolphins ( Tursiops truncatus) in Sarasota Bay, Florida  

Microsoft Academic Search

Research initiated in 1970 has identified a long-term, year-round resident community of about 140 bottlenose dolphins (Tursiops truncatus) in Sarasota Bay, Florida, providing unparalleled opportunities to investigate relationships between organochlorine contaminant residues and life-history and reproductive parameters. Many individual dolphins are identifiable and of known age, sex, and maternal lineage (?4 generations). Observational monitoring provides data on dolphin spatial and

Randall S. Wells; Victoria Tornero; Asuncion Borrell; Alex Aguilar; Teri K. Rowles; Howard L. Rhinehart; Suzanne Hofmann; Walter M. Jarman; Aleta A. Hohn; Jay C. Sweeney

2005-01-01

352

Reproduction, survival, and life table parameters of the predatory mite Cheyletus malaccensis (Acari: Cheyletidae) at various constant temperatures.  

PubMed

Reproduction, survival, and life table parameters of the predatory mite Cheyletus malaccensis Oudemans were evaluated at six constant temperatures: 17.5, 20, 25, 30, 32.5 and 35°C, feeding on Tyrophagus putrescentiae (Schrank). Preoviposition period of fertilized and virgin females varied with temperature from ca. 9 days at 17.5°C to ca. 1.5 day at 32.5°C and then increased to ca. 3 days at 35°C. Virgin female oviposition period was significantly shorter than for fertilized females at the temperatures examined with the exception of 17.5°C. The mean total number of eggs per fertilized (169.7 ± 6.6) and virgin female (60.7 ± 4.3) was highest at the temperature of 30°C. The data indicated a significant positive and nearly doubling effect of fertilization on female fecundity at the temperatures examined with the exception of 17.5°C. Age-specific fecundity was described by a temperature dependent model from which the maximum daily fecundity rate was estimated for fertilized and virgin females at 10.3 (at 30°C) and 6.8 (at 32.5°C) eggs/female, respectively. Virgin female longevity was significantly shorter than for fertilized females at 20, 30 and 32.5°C, and decreased from ca. 57 days at 17.5°C to ca. 17 days at 35°C. The Weibull function that was used to describe the age specific survival of fertilized and virgin females produced excellent fits to the survival data. Estimates of intrinsic rate of increase, net reproductive rate, mean generation time, doubling time and finite rate of increase, were obtained. The r(m) value increased with temperature from 0.03 (day(-1)) at 17.5°C to 0.21 (day(-1)) at 32.5°C, after which it decreased to 0.15 (day(-1)) at 35°C. These data indicate that C. malaccensis can reproduce at temperatures between 17.5 and 35°C and can be used for biological control of astigmatid mites within the temperature range where the pest occurs. PMID:21287248

Palyvos, Nickolas E; Emmanouel, Nickolas G

2011-06-01

353

Spanning trees of graphs Spanning trees of simplicial complexes  

E-print Network

Spanning trees of graphs Spanning trees of simplicial complexes Color-shifted complexes Weighted spanning tree enumerators of color-shifted complexes Ghodratollah Aalipour1,2 Art Duval1 1University Ghodratollah Aalipour, Art Duval Spanning tree enumerators of color-shifted complexes #12;Spanning trees

Duval, Art

354

Spanning trees of graphs Spanning trees of simplicial complexes  

E-print Network

Spanning trees of graphs Spanning trees of simplicial complexes Complete colorful complexes Weighted spanning tree enumerators of complete colorful complexes Ghodratollah Aalipour1,2 Art Duval1 1 Aalipour, Art Duval Spanning tree enumerators of complete colorful complexes #12;Spanning trees of graphs

Duval, Art

355

New prospects for a prolonged functional life-span of artificial hip joints by using the material combination polyethylene/aluminium oxide ceramin/metal.  

PubMed

Investigations over the years have shown that the mirror-finished Al2O3 ceramic is a much more suitable frictional counterpart to ultrahigh molecular weight (UHMW) polyethylene than metal. Despite the extremely gread hardness difference between polyethylene and Al2O3 ceramic, a considerable lower wear rate is obtained for the polyethylene socked with this new low-friction material combination. The unexpectedly favorable tribological behavior of this ceramic material in contact with polyethylene may be attributed to the following factors: better values for corrosion resistance characteristics, wettability with liquids, surfact gloss, hardness, and scratch resistance of the ceramic material in comparison with those of the hitherto used metallic implant materials (AISI-316L steel or cast Co-Cr-Mo alloy). It appears that, by using this new combination of materials for the socket and the ball, it will be possible to prolong the service life of artificial hip joints considerably without having effecy any fundamental changes in the present design and implantation principle retaining the hitherto used anchorage shaft made of wrought Co-Ni-Cr-Mo-Ti alloy Protasul-10 of extremely high corrosion fatigue strength. PMID:559675

Semlitsch, M; Lehmann, M; Weber, H; Doerre, E; Willert, H G

1977-07-01

356

The Minimum Labeling Spanning Trees  

Microsoft Academic Search

One of the fundamental problems in graph theory is to compute a minimum weight spanning tree. In this paper, a variant of spanning trees, called the minimum labeling spanning tree, is studied. The purpose is to find a spanning tree that tries to use edges that are as similar as possible. Giving each edge a label, the minimum labeling spanning

Ruay-Shiung Chang; Shing-jiuan Leu

1997-01-01

357

Tracking bacterial growth in liquid media and a new bacterial life model  

Microsoft Academic Search

By increasing viscosity of liquid media above 8.4 centipoise (cp) i.e. 0.084 g· cm-1 · s-1, individual growth and family formation ofEscherichia coli was continuously observed in real-time for up to 6 h. The observations showed primarily unidirectional growth and reproduction\\u000a ofE. coli and suggested more than one reproduction in the observed portion ofE. coli life span. A new bacterial

Shi Liu

1999-01-01

358

Life-span effects of ionizing radiation in the beagle dog: A summary account of four decades of research funded by the US Department of Energy and its predecessor agencies  

SciTech Connect

Nearly 40 years ago, the US Atomic Energy Commission made a far- reaching commitment to the support of life-span radiation-effects studies in a relatively long-lived animal, the beagle dog. Something in the range of 200 million dollars has already been spent on a group of closely related experiments, many of which are only now coming to fruition. Responsible fiscal management of these studies, directed toward securing an optimum return from past investments, and toward creative planning of future directions, requires a comprehensive view of this total effort. This report is designed to provide that comprehensive view. This is primarily intended as a research management document. Evaluation and interpretation are tasks for those directly involved in conducting these experiments. The limited objective of the present document is to describe what has been done, to give some of the background for why it was done, to describe results already realized and applications that have been made of these results -- all in a manner designed to display the total effort rather than piecemeal details. While proposing no specific answers to the questions ''Where do we go from here.''it is hoped that the document will provide a basis for approaching that question in an informed manner. The maintenance of a continuity of scientific understanding and direction in these experiments, which often continue beyond the initiating investigators' working life, is no small part of the problem involved in conducting these experiments.

Thompson, R.C.

1989-01-01

359

My Reproductive Life Plan  

MedlinePLUS

... About CDC.gov . Preconception Home Overview Planning for Pregnancy Women Men Health Professionals Clinical Care for Women Health Promotion Personal History Nutrition Immunization Infectious Disease Medical Conditions Exposures Psychosocial Risks Special ...

360

Oosorption in response to poor food: complexity in the trade-off between reproduction and survival.  

PubMed

Plasticity in reproductive physiology is one avenue by which environmental signals, such as poor quality food, can be coordinated with adaptive responses. Insects have the ability to resorb oocytes that are not oviposited. Oosorption is proposed to be an adaptive mechanism to optimize fitness in hostile environments, recouping resources that might otherwise be lost, and reinvesting them into future reproductive potential. We tested the hypothesis that oosorption is an evolved mechanism by which females can reallocate resources from current reproductive effort to survival and future reproduction, when conditions for reproduction are poor, by examining the reproductive physiology and life-history outcome under poor quality food in populations of the milkweed bug (Oncopeltus fasciatus) that have adapted to live on sunflower seed. Females fed a diet of pumpkin seeds, known to be a poor host food, had higher levels of ovarian apoptosis (oosorption), lower reproductive output, but no reduction in life span under poor nutrition, as predicted under the oosorption hypothesis. However, the schedule of reproduction was surprising given the "wait to reproduce" assumption of oosorption as early fecundity was unaffected. PMID:22393481

Moore, Patricia J; Attisano, Alfredo

2011-09-01

361

Toxicity of copper-spiked sediments to Tubifex tubifex (Oligochaeta, Tubificidae): Comparison of the 28-day reproductive bioassay with an early-life-stage bioassay  

SciTech Connect

Two sediment bioassay methods using Tubifex tubifex (Mueller, 1774) as the test species were compared. The first was an adult reproduction test, the second an early-life-stage survival test. The duration of both bioassays is 28 d and the amount of work required was similar; they may be useful alternatives to each other in different circumstances (e.g., the early life stage bioassay could be carried out with smaller volumes of sediment). The two bioassays were performed simultaneously on copper-spiked sediments. Sediments from two freshwater and two terrestrial sites were used; five separate, nonsimultaneous experiments were performed, one for each sediment or soil and a further experiment with soil with a good supplement. In the adult bioassay, there were large differences in the production of cocoons, eggs, and young among the control treatments of the five experiments. There were also major differences in the NOEC and LOEC for copper between the tested substrates. The early life stage bioassay appears to be less sensitive to copper toxicity than the adult reproductive bioassay since NOECs and LOECs are higher for early survival than for the most sensitive endpoints of the adult bioassay in three experiments out of five.

Vecchi, M.; Pasteris, A.; Bonomi, G. (Univ. degli Studi di Bologna (Italy). Dipt. di Biologia Evoluzionistica Sperimentale); Reynoldson, T.B. (Environment Canada, Burlington, Ontario (Canada). National Water Research Inst.)

1999-06-01

362

5. VIEW OF SPAN ADJOINING SPAN TO THE NORTH OF ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

5. VIEW OF SPAN ADJOINING SPAN TO THE NORTH OF THE VERTICAL LIFT SPAN (IN THE DISTANCE IS THE RECENTLY COMPLETED NEW STATE ROUTE 51 BRIDGE CROSSING THE ILLINOIS RIVER). - Shippingsport Bridge, Spanning Illinois River at State Route 51, La Salle, La Salle County, IL

363

Spanning trees of graphs Spanning trees of simplicial complexes  

E-print Network

Spanning trees of graphs Spanning trees of simplicial complexes Critical group of graphs Critical group of simplicial complexes Spanning trees and the critical group of simplicial complexes Art Duval1 of Kansas Mathematics Seminar Reed College April 28, 2011 Duval, Klivans, Martin Spanning trees

Duval, Art

364

Spanning trees of graphs Spanning trees of simplicial complexes  

E-print Network

Spanning trees of graphs Spanning trees of simplicial complexes Critical group of graphs Critical group of simplicial complexes Spanning trees and the critical group of simplicial complexes Art Duval1 of Kansas Discrete CATS seminar University of Kentucky March 30, 2011 Duval, Klivans, Martin Spanning trees

Duval, Art

365

Spanning trees of graphs Spanning trees of simplicial complexes  

E-print Network

Spanning trees of graphs Spanning trees of simplicial complexes Critical group of graphs Critical group of simplicial complexes Spanning trees and the critical group of simplicial complexes Art Duval1 Mathematics Colloquium New Mexico State University October 20, 2011 Duval, Klivans, Martin Spanning trees

Duval, Art

366

Spanning trees of graphs Spanning trees of simplicial complexes  

E-print Network

Spanning trees of graphs Spanning trees of simplicial complexes Complete colorful complexes Weighted spanning tree enumerators of complete colorful complexes Ghodratollah Aalipour1,2 Art Duval1 1 of Mississippi March 2, 2013 Ghodratollah Aalipour, Art Duval Spanning tree enumerators of complete colorful

Duval, Art

367

Spanning trees of graphs Spanning trees of simplicial complexes  

E-print Network

Spanning trees of graphs Spanning trees of simplicial complexes Complete colorful complexes Weighted spanning tree enumerators of complete colorful complexes Ghodratollah Aalipour1,2 Art Duval1 1 April 21, 2013 Ghodratollah Aalipour, Art Duval Spanning tree enumerators of complete colorful complexes

Duval, Art

368

Spanning trees of graphs Spanning trees of simplicial complexes  

E-print Network

Spanning trees of graphs Spanning trees of simplicial complexes Color-shifted complexes Weighted spanning tree enumerators of color-shifted complexes Ghodratollah Aalipour1,2 Art Duval1 1University in St. Louis October 20, 2013 Ghodratollah Aalipour, Art Duval Spanning tree enumerators of color

Duval, Art

369

C-SPAN Classroom  

NSDL National Science Digital Library

Over the past several decades, C-SPAN has brought many hours of fascinating programming to the generally curious. Many teachers have used their programming to edify their students about various aspects of US government, and now C-SPAN has created this very nice site to complement those informal activities. The formal mission of the C-SPAN Classroom site is "to enhance the teaching of Civics & U.S. Government through C-SPAN's primary source programming." Visitors can start their journey by viewing the "Clip of the Week", and then looking through the other thematic sections on the site, which include "Principles of Government", "Legislative Branch", and "Political Participation". Along with each clip, users can also view a short clip description, and take advantage of the discussion questions as well. Visitors will need to complete a short free registration form to access all of the clips, and this only takes a few minutes. This site is quite a delight, and for anyone who teaches civics and related fields, it will most likely become an essential online resource.

370

An insulin-like signaling pathway affects both longevity and reproduction in Caenorhabditis elegans.  

PubMed Central

Mutations in daf-2 and age-1 cause a dramatic increase in longevity as well as developmental arrest at the dauer diapause stage in Caenorhabditis elegans. daf-2 and age-1 encode components of an insulin-like signaling pathway. Both daf-2 and age-1 act at a similar point in the genetic epistasis pathway for dauer arrest and longevity and regulate the activity of the daf-16 gene. Mutations in daf-16 cause a dauer-defective phenotype and are epistatic to the diapause arrest and life span extension phenotypes of daf-2 and age-1 mutants. Here we show that mutations in this pathway also affect fertility and embryonic development. Weak daf-2 alleles, and maternally rescued age-1 alleles that cause life span extension but do not arrest at the dauer stage, also reduce fertility and viability. We find that age-1(hx546) has reduced both maternal and zygotic age-1 activity. daf-16 mutations suppress all of the daf-2 and age-1 phenotypes, including dauer arrest, life span extension, reduced fertility, and viability defects. These data show that insulin signaling, mediated by DAF-2 through the AGE-1 phosphatidylinositol-3-OH kinase, regulates reproduction and embryonic development, as well as dauer diapause and life span, and that DAF-16 transduces these signals. The regulation of fertility, life span, and metabolism by an insulin-like signaling pathway is similar to the endocrine regulation of metabolism and fertility by mammalian insulin signaling. PMID:9504918

Tissenbaum, H A; Ruvkun, G

1998-01-01

371

Planar Bichromatic Minimum Spanning Trees  

E-print Network

Planar Bichromatic Minimum Spanning Trees Magdalene G. Borgelt Marc van Kreveld Maarten L Bichromatic Minimum Spanning Trees Magdalene G. Borgelt1 Marc van Kreveld2 Maarten L¨offler2 Jun Luo2 Damian points in the plane, a planar bichromatic minimum spanning tree is the shortest possible spanning tree

Utrecht, Universiteit

372

95. Reproduction from glass plate negative (Modjeski and Masters office, ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

95. Reproduction from glass plate negative (Modjeski and Masters office, Modjeski Collection, No. 150, January 18, 1908) SPANS 4 AND 5 - Burlington Northern Railroad Bridge, Spanning Willamette River at River Mile 6.9, Portland, Multnomah County, OR

373

100. Reproduction from glass plate negative (Modjeski and Masters office, ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

100. Reproduction from glass plate negative (Modjeski and Masters office, Modjeski Collection, No. 198, July 25, 1908) VIEW OF DRAW SPAN - Burlington Northern Railroad Bridge, Spanning Willamette River at River Mile 6.9, Portland, Multnomah County, OR

374

89. Reproduction from glass plate negative (Modjeski and Masters office, ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

89. Reproduction from glass plate negative (Modjeski and Masters office, Modjeski Collection, No. 6, not dated) DRAW SPAN - Burlington Northern Railroad Bridge, Spanning Willamette River at River Mile 6.9, Portland, Multnomah County, OR

375

98. Reproduction from glass plate negative (Modjeski and Masters office, ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

98. Reproduction from glass plate negative (Modjeski and Masters office, Modjeski Collection, No. 181, May 5, 1908) STEEL ERECTION AT DRAW SPAN - Burlington Northern Railroad Bridge, Spanning Willamette River at River Mile 6.9, Portland, Multnomah County, OR

376

Conflict and Cooperation across the Life Span  

E-print Network

) identified five major conflict management styles: competing, collaborating (or problem solving), avoiding, compromising, and accommodating (? Interpersonal Conflict). These five styles have been applied, adapted and validated in slightly different ways... coworker who was cooperative and least satisfaction with a young co-worker who competed. Bergstrom and Nussbaum (1996) examined younger and older adults’ general conflict style preferences. Participants completed a conflict questionnaire and recalled...

Zhang, Yan Bing

2008-01-01

377

Getting Serious Play: Life Span Career Education  

ERIC Educational Resources Information Center

Canada's $76.5 billion annual investment in education is paying dividends. A recent international survey ranked Canadian students "second" in reading literacy, "fifth" in mathematics and "fifth" in science. For nations and individuals alike, such mastery is intrinsic to success in the new knowledge economy. Yet, mastering these academic skills in…

Jarvis, Phil; Esbin, Howard

2006-01-01

378

Life Span Differences in Color Dreaming  

Microsoft Academic Search

We examined evidence for developmental and generational differences in dreaming in color from childhood to old age. To separate these effects, we surveyed the frequency of color experience in dreams twice, with a 16-year interval between surveys. In the 1993 survey, 2,077 (male: 1,194; female: 883; ages: 10 to 85 years) and, in 2009, 1,328 (male: 596; female: 732; ages:

Hitoshi Okada; Kazuo Matsuoka; Takao Hatakeyama

2011-01-01

379

The life span of the biosphere revisited  

NASA Technical Reports Server (NTRS)

How much longer the biosphere can survive on earth is reexamined using a more elaborate model than that of Lovelock and Whitfield (1982). The model includes a more accurate treatment of the greenhouse effect of CO2, a biologically mediated weathering parametrization, and the realization that C4 photosynthesis can persist to much lower concentrations of atmospheric CO2. It is found that a C4-plant-based biosphere could survive for at least another 0.9 Gyr to 1.5 Gyr after the present time, depending respectively on whether CO2 or temperature is the limiting factor. Within an additional 1 Gyr, earth may lose water to space, thereby following the path of Venus.

Caldeira, Ken; Kasting, James F.

1992-01-01

380

More Whole Grains May Boost Life Span  

MedlinePLUS

... study, researchers looked at whole fiber -- the whole seed of grain that's used in grain products like ... density, such as fruit, vegetables, whole grains, nuts, seeds, and legumes," Ma added. "There is no upper ...

381

Metamemory through the Adult Life Span.  

ERIC Educational Resources Information Center

The present experiment was designed to assess possible age-related differences in metamemory accuracy and efficiency by using a feeling-of-knowing judgment in conjunction with a timed question-answering task. Subjects were 12 college students (19-22 years of age), 12 middle-aged (44-53 years) and 12 elderly (65-74 years) persons. (Author/MP)

Lachman, Janet L.; And Others

1979-01-01

382

Mental Health Disorders May Shorten Life Span  

MedlinePLUS

... health conditions such as depression, chronic anxiety and schizophrenia tend to die at younger ages than their ... mortality across a range of mental health disorders." Schizophrenia and other types of psychoses -- among the most ...

383

Community attitude towards the reproductive rights and sexual life of people living with HIV/AIDS in Olorunda Local Government Area, Osogbo, Nigeria  

PubMed Central

Background Globally, the Human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS) epidemic remains a major public health problem. In most countries in sub-Saharan Africa, HIV/AIDS has already reversed the post-independence developmental gains. Purpose This study assessed community attitudes regarding the reproductive rights and sexual life of people living with HIV/AIDS (PLWHA) in Olorunda Local Government Area of Osun State, Southwestern Nigeria. Design and methods In a community-based descriptive cross-sectional study, the sample size calculation was based on the assumption that 67% of the target population has a negative attitude regarding the reproductive rights of PLWHA; a confidence interval (CI) of 95% was used. A minimum sample size of 340 was obtained using the formula n = Z2pq/d2. An anticipated 10% nonresponse rate was added to obtain a sample size of 374; a multistage sampling technique was utilized to select a total of 450 respondents. Data collected through a semistructured standardized and pretested questionnaire were analyzed using Statistical Package for Social Sciences software, version 15. Results The study revealed that 283 (66.6%) and 142 (33.4%) of respondents were urban and rural dwellers, respectively. Mean age of respondents was 28.7 years ± 2.2 years. Four hundred and two (94.6%) respondents were aware of HIV/AIDS, and 88.7% had knowledge of at least six different modes of HIV/AIDS transmission. About 30.7% of respondents had discriminatory and stigmatizing attitudes towards PLWHA, and 50.9% and 44.8% had negative attitudes towards their sexual and reproductive rights, respectively. There were significant associations between gender, marital status, educational status, occupation, and residential area of respondents and their attitude towards the reproductive and sexual right of PLWHA (P < 0.05). Conclusion and recommendation Discriminatory and stigmatizing attitudes to PLWHA found among respondents translated into a negative attitude regarding the reproductive and sexual rights of PLWHA. There is an urgent need to institute programs for raising community awareness about the rights of PLWHA, especially in rural areas, and to strengthen legislative provisions for protecting and preserving the reproductive rights of PLWHA. PMID:23807862

Asekun-Olarinmoye, EO; Asekun-Olarinmoye, IO; Adebimpe, WO; Olugbenga-Bello, AI

2013-01-01

384

Characteristics of an infinite life span diploid human fibroblast cell strain and a near-diploid strain arising from a clone of cells expressing a transfected v-myc oncogene  

SciTech Connect

Diploid human fibroblasts were transfected with a plasmid carrying a v-myc oncogene linked to the neo gene or with a vector control carrying a neo gene. Drug-resistant clones were isolated and subcultured as needed. All populations went into crisis and eventually senesced. But while they were senescing, viable-appearing clones were noted among the progeny of a transfected population that expressed the v-myc oncogene. After several months, these cells began replicating more rapidly. Karyotype analysis indicated that they were clonally derived since all of them had 45 chromosomes, including 2 marker chromosomes. This cell strain was designated MSU-1.1. Similar analysis showed that cells from an earlier passage were diploid. These cells were designated MSU-1.0. The expression of v-myc is probably required for acquisition of an infinite life span, since this phenotype did not develop in populations not expressing this oncogene. However, expression of v-myc is clearly not sufficient, since all of the progeny of the clone that gave rise to the MSU-1.0 cells expressed this oncogene, but the vast majority of them senesced.

Morgan, T.L.; Dajun Yang; Fry, D.G.; Hurlin, P.J.; Kohler, S.K.; Maher, V.M.; McCormick, J.J. (Michigan State Univ., East Lansing (United States))

1991-11-01

385

A Report from the 2013 International Symposium: The Evaluation of the Effects of Low-dose Radiation Exposure in the Life Span Study of Atomic Bomb Survivors and Other Similar Studies.  

PubMed

The RERF International Low-Dose Symposium was held on 5-6 December 2013 at the RERF campus in Hiroshima, Japan, to discuss the issues facing the Life Span Study (LSS) and other low-dose studies. Topics included the current status of low-dose risk detection, strategies for low-dose epidemiological and statistical research, methods to improve communication between epidemiologists and biologists, and the current status of radiological studies and tools. Key points made by the participants included the necessity of pooling materials over multiple studies to gain greater insight where data from single studies are insufficient; generating models that reflect epidemiological, statistical, and biological principles simultaneously; understanding confounders and effect modifiers in the current data; and taking into consideration less studied factors such as the impact of dose rate. It is the hope of all participants that this symposium be used as a trigger for further studies, especially those using pooled data, in order to reach a greater understanding of the health effects of low-dose radiation. PMID:25811153

Grant, E J; Ozasa, K; Ban, N; de González, A Berrington; Cologne, J; Cullings, H M; Doi, K; Furukawa, K; Imaoka, T; Kodama, K; Nakamura, N; Niwa, O; Preston, D L; Rajaraman, P; Sadakane, A; Saigusa, S; Sakata, R; Sobue, T; Sugiyama, H; Ullrich, R; Wakeford, R; Yasumura, S; Milder, C M; Shore, R E

2015-05-01

386

Life-history plasticity after attaining a dietary threshold for reproduction is associated with protein storage in flesh flies  

Microsoft Academic Search

Summary 1. Body condition affects the timing and magnitude of life-history transitions. Therefore, identifying proximate mechanisms involved in assessing condition is critical to understanding how these mechanisms affect the expression of life-history plasticity. Nutrient storage is an important body condition parameter, likely playing roles in both attaining minimum body-condition thresholds for life-history transitions and expression of life-history traits. 2. We

D. A. Hahn; L. N. James; K. R. Milne; J. D. Hatle

2008-01-01

387

C-SPAN Classroom  

NSDL National Science Digital Library

The C-SPAN in the classroom website is geared toward teachers of political science - or specifically U.S. Government. The site is split into six segments: Principles of Government, the Constitution, Political Participation and each of the three branches of government. Each of these sections features video clips, and questions for class discussion. Free site membership is available, but not required to use the site. Some additional content and services are available with membership.

388

Early is better: seasonal egg fitness and timing of reproduction in a zooplankton life-history model  

E-print Network

because climate change may influence the timing of annual biological events (Both et al. 2006, Jonze´n et food availability and predation risk fluctuate seasonally. Marine zooplankton have evolved a diversity. Many plants and animals experience environmental conditions that allow growth or reproduction only

Heino, Mikko

389

Span efficiency in hawkmoths  

PubMed Central

Flight in animals is the result of aerodynamic forces generated as flight muscles drive the wings through air. Aerial performance is therefore limited by the efficiency with which momentum is imparted to the air, a property that can be measured using modern techniques. We measured the induced flow fields around six hawkmoth species flying tethered in a wind tunnel to assess span efficiency, ei, and from these measurements, determined the morphological and kinematic characters that predict efficient flight. The species were selected to represent a range in wingspan from 40 to 110 mm (2.75 times) and in mass from 0.2 to 1.5 g (7.5 times) but they were similar in their overall shape and their ecology. From high spatio-temporal resolution quantitative wake images, we extracted time-resolved downwash distributions behind the hawkmoths, calculating instantaneous values of ei throughout the wingbeat cycle as well as multi-wingbeat averages. Span efficiency correlated positively with normalized lift and negatively with advance ratio. Average span efficiencies for the moths ranged from 0.31 to 0.60 showing that the standard generic value of 0.83 used in previous studies of animal flight is not a suitable approximation of aerodynamic performance in insects. PMID:23658113

Henningsson, Per; Bomphrey, Richard J.

2013-01-01

390

Reproduction in Northern krill (Meganyctiphanes norvegica Sars).  

PubMed

This review presents the current state of knowledge with regard to the reproductive biology of Northern krill (Meganyctiphanes norvegica). Reproduction is limited to a distinct period of the year. First development of the ovary occurs at the onset of the season, when the stock of primary oocytes issued from the germinal zone starts to accumulate glycoproteic yolk. Previtellogenesis continues throughout the entire reproductive season, but oosorption (the retrieval by the ovary of the yolk constituents from the growing oocytes) may occur in unfavourable conditions and represents an important metabolic process for sustaining females during such periods. Oosorption also occurs at the onset of the resting season. It has been established that individual females may perform several cycles of reproduction each year. Each reproductive cycle spans two moult cycles, one in which lipid yolk is accumulated (vitellogenesis) and another when spawning occurs. The time of spawning does not coincide with the moult (ecdysis), but with the onset of moult preparation (C-D0 moult stages). The complete egg-batch is spawned well before the moult. Storage lipids are accumulated preferentially in the ovary with distinctly high levels of ?-3 polyunsaturated fatty acids in the polar lipid fraction as well as phosphatidylcholine, a key component in the development of the embryo. There is no difference concerning lipid storage between resting females, males and juvenile krill. Beside the ovary, the fat body is an important organ involved in the metabolism and storage of the glycoproteins and lipids that will be transformed into the lipoglycoproteins of the yolk platelets in the ovary. M. norvegica produce large egg batches with the number of mature oocytes in one batch being proportional to the size of the female, with a mean number of 1000-1200 eggs per batch. The number of reproductive cycles per year is a function of the trophic conditions, with the first reproductive cycle being triggered by the first phytoplankton bloom. Other reproductive features reflect specific adaptations of krill to a pelagic life, like swarming and vertical migration behaviour. M. norvegica segregate at night for moulting and mating or spawning, while swimming constantly during their diel vertical migration (DVM). Key questions concerning krill reproduction remain, particularly in identifying the cues that switch krill in and out reproductive development, or between egg-building and oosorption. New molecular tools are now available to tackle such questions. PMID:20955893

Cuzin-Roudy, Janine

2010-01-01

391

An empirical test of evolutionary theories for reproductive senescence and reproductive effort in the garter snake Thamnophis elegans  

Microsoft Academic Search

Evolutionary theory predicts that differential reproductive effort and rate of reproductive senescence will evolve under different rates of external mortality. We examine the evolutionary divergence of age-specific reproduction in two life-history ecotypes of the western terrestrial garter snake, Thamnophis elegans. We test for the signature of reproductive senescence (decreasing fecundity with age) and increasing reproductive effort with age (increasing reproductive

Amanda M. Sparkman; Stevan J. Arnold; Anne M. Bronikowski

2007-01-01

392

An emerging interface between life science and nanotechnology: present status and prospects of reproductive healthcare aided by nano-biotechnology  

PubMed Central

Among the various applications of nano-biotechnology, healthcare is considered one of the most significant domains. For that possibility to synthesize various kind of nanoparticles (NPs) and the ever-increasing ability to control their size as well as structure, to improve surface characteristics and binding NPs with other desired curing agents has played an important role. In this paper, a brief sketch of various kinds of nanomaterials and their biomedical applications is given. Despite claims of bio-nanotechnology about to touch all areas of medical science, information pertaining to the role of nanotechnology for the betterment of reproductive healthcare is indeed limited. Therefore, the various achievements of nano-biotechnology for healthcare in general have been illustrated while giving special insight into the role of nano-biotechnology for the future of reproductive healthcare betterment as well as current achievements of nanoscience and nanotechnology in this arena. PMID:24600516

Jha, Rakhi K.; Jha, Pradeep K.; Chaudhury, Koel; Rana, Suresh V.S.; Guha, Sujoy K.

2014-01-01

393

Growth and reproduction of the mosquitofish, Gambusia affinis , in relation to temperature and ration level: consequences for life history  

Microsoft Academic Search

Synopsis  The allocation of energy to growth and reproduction, in relation to temperature and food availability, was investigated in\\u000a laboratory experiments with the mosquitofish,Gambusia affinis. At constant temperature of 20, 25 and 30°C and ad libitum feeding, specific growth rates increased with increasing temperature\\u000a at 1.7, 3.1 and 3.4% dry mass day?1, respectively. Growth rates in a cycling temperature regime (20–30°C,

Bruce Vondracek; Wayne A. Wurtsbaugh; Joseph J. Cech

1988-01-01

394

Eight Nucleotide Substitutions Inhibit Splicing to HPV-16 3?-Splice Site SA3358 and Reduce the Efficiency by which HPV-16 Increases the Life Span of Primary Human Keratinocytes  

PubMed Central

The most commonly used 3?-splice site on the human papillomavirus type 16 (HPV-16) genome named SA3358 is used to produce HPV-16 early mRNAs encoding E4, E5, E6 and E7, and late mRNAs encoding L1 and L2. We have previously shown that SA3358 is suboptimal and is totally dependent on a downstream splicing enhancer containingmultiple potential ASF/SF2 binding sites. Here weshow that only one of the predicted ASF/SF2 sites accounts for the majority of the enhancer activity. We demonstrate that single nucleotide substitutions in this predicted ASF/SF2 site impair enhancer function and that this correlates with less efficient binding to ASF/SF2 in vitro. We provide evidence that HPV-16 mRNAs that arespliced to SA3358 interact with ASF/SF2 in living cells. In addition,mutational inactivation of the ASF/SF2 site weakened the enhancer at SA3358 in episomal forms of the HPV-16 genome, indicating that the enhancer is active in the context of the full HPV-16 genome.This resulted in induction of HPV-16 late gene expression as a result of competition from late splice site SA5639. Furthermore, inactivation of the ASF/SF2 site of the SA3358 splicing enhancer reduced the ability of E6- and E7-encoding HPV-16 plasmids to increase the life span of primary keratinocytes in vitro, demonstrating arequirement for an intact splicing enhancer of SA3358 forefficient production of the E6 and E7 mRNAs. These results link the strength of the HPV-16 SA3358 splicing enhancer to expression of E6 and E7 and to the pathogenic properties of HPV-16. PMID:24039800

Li, Xiaoze; Johansson, Cecilia; Cardoso Palacios, Carlos; Mossberg, Anki; Dhanjal, Soniya; Bergvall, Monika; Schwartz, Stefan

2013-01-01

395

Assignment: Minimum Spanning Trees Name: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  

E-print Network

Algorithms Assignment: Minimum Spanning Trees Name 0 11 1 0 00 1 11 0 00 1 11 0011 (a) Find a spanning tree for the Petersen graph with minimum height is at most 2. 2 #12;2. Minimum and maximum spanning trees for the weighted Petersen graph. I J E 4 3 H B C D

Bar-Noy, Amotz

396

Changes in reproductive life-history strategies in response to nest density in a shell-brooding cichlid, Telmatochromis vittatus.  

PubMed

To determine whether the appearance of a reproductively parasitic tactic varies, and how this variation affects territorial males of the Lake Tanganyika cichlid fish Telmatochromis vittatus, we examined the reproductive ecology of territorial males in Mtondwe and compared it with that of a neighboring Wonzye population, where nest density differs from that at Mtondwe. In Wonzye, with high nest density, male tactics change with their body size from a territorial to a non-territorial parasitic tactic called piracy in which they conquer several nests defended by territorial males and take over the nests while females are spawning. These "pirate" males could decrease the costs incurred by travelling among nests by exclusively targeting aggregations of nests in close proximity while avoiding separate nests. Territorial males in Wonzye sacrifice the potential higher attractiveness offered by large nests and instead compete for nests farther from neighbors on which pirates less frequently intrude. In contrast, the Mtondwe population had lower nest density and piracy was absent. Given that the success of piracy depends on the close proximity of nests, nest density is likely responsible for the observed variation in the occurrence of piracy between the two populations. Furthermore, in Mtondwe, territorial males competed for larger nests and were smaller than the territorial males in Wonzye. Thus, this lower nest density may free territorial males from the selection pressures for increased size caused by both defense against nest piracy and the need to develop into pirates as they grow. PMID:22089034

Ota, Kazutaka; Hori, Michio; Kohda, Masanori

2012-01-01

397

Changes in reproductive life-history strategies in response to nest density in a shell-brooding cichlid, Telmatochromis vittatus  

NASA Astrophysics Data System (ADS)

To determine whether the appearance of a reproductively parasitic tactic varies, and how this variation affects territorial males of the Lake Tanganyika cichlid fish Telmatochromis vittatus, we examined the reproductive ecology of territorial males in Mtondwe and compared it with that of a neighboring Wonzye population, where nest density differs from that at Mtondwe. In Wonzye, with high nest density, male tactics change with their body size from a territorial to a non-territorial parasitic tactic called piracy in which they conquer several nests defended by territorial males and take over the nests while females are spawning. These "pirate" males could decrease the costs incurred by travelling among nests by exclusively targeting aggregations of nests in close proximity while avoiding separate nests. Territorial males in Wonzye sacrifice the potential higher attractiveness offered by large nests and instead compete for nests farther from neighbors on which pirates less frequently intrude. In contrast, the Mtondwe population had lower nest density and piracy was absent. Given that the success of piracy depends on the close proximity of nests, nest density is likely responsible for the observed variation in the occurrence of piracy between the two populations. Furthermore, in Mtondwe, territorial males competed for larger nests and were smaller than the territorial males in Wonzye. Thus, this lower nest density may free territorial males from the selection pressures for increased size caused by both defense against nest piracy and the need to develop into pirates as they grow.

Ota, Kazutaka; Hori, Michio; Kohda, Masanori

2012-01-01

398

Caloric restriction: Impact upon pituitary function and reproduction  

PubMed Central

Reduced energy intake, or caloric restriction (CR), is known to extend life span and to retard age-related health decline in a number of different species, including worms, flies, fish, mice and rats. CR has been shown to reduce oxidative stress, improve insulin sensitivity, and alter neuroendocrine responses and central nervous system (CNS) function in animals. CR has particularly profound and complex actions upon reproductive health. At the reductionist level the most crucial physiological function of any organism is its capacity to reproduce. For a successful species to thrive, the balance between available energy (food) and the energy expenditure required for reproduction must be tightly linked. An ability to coordinate energy balance and fecundity involves complex interactions of hormones from both the periphery and the CNS and primarily centers upon the master endocrine gland, the anterior pituitary. In this review article we review the effects of CR on pituitary gonadotrope function and on the male and female reproductive axes. A better understanding of how dietary energy intake affects reproductive axis function and endocrine pulsatility could provide novel strategies for the prevention and management of reproductive dysfunction and its associated comorbidities. PMID:18329344

Martin, Bronwen; Golden, Erin; Carlson, Olga D.; Egan, Josephine M.; Mattson, Mark P.; Maudsley, Stuart

2008-01-01

399

Health-Related Quality of Life and Primi-Gravid: A Comparative Study of Natural Conception and Conception by Assisted Reproduction Technologies (ARTs)  

PubMed Central

Background Childbearing for the first time is a unique experience. Quality of life is an important indicator in health studies. This study aimed to assess the quality of life of women who were conceived by ARTs and had successful childbirth for the first time and to compare it with quality of life in women who become pregnant naturally and similarly had successful childbirth for the first time. Materials and Methods This was a cross sectional comparative study. The accessible sam- ple was recruited from patients attending an infertility clinic and two obstetric and gynecology clinics in Tehran, Iran, during March 2010 to March 2011. In all 276 patients were approached. Of these, 162 women (76 women in natural conception group and 86 women in assisted reproduction technologies group) who met the inclusion criteria were entered into the study. Quality of life was assessed using the 36-item Short Form Health Survey (SF-36). Women completed the questionnaire at two time points: i. last trimester and ii. first month after delivery. Comparison was made between two groups using Mann-Whitney U test and paired samples t test. Results Comparing the SF-36 scores between women in natural conception group and ARTs group before childbirth, it was found that natural group had better condition on physical functioning, role limitation due to physical problems, bodily pain and social functioning, while the ARTs group reported better status on general health, vitality, role limitation due to emotional problems, and mental health. However, after childbirth, the ARTs group reported a better condition almost on all measures, except for physical functioning. Comparing differences in obtained scores between two groups before and after childbirth, the results showed that improvements in health related quality of life measures for the ARTs group were greater in all measures, expect for general health. Conclusion The findings from this study suggest that health-related quality of life was improved in women who became a mother for the first time by either method. Comparing to women who became mother by natural conception, women who received ARTs showed better quality of life from this first successful experience. PMID:25083182

Ahmadi, Seyed Ebrahim; Montazeri, Ali; Mozafari, Ramin; Azari, Afsaneh; Nateghi, Mohammad Reza; Ashrafi, Mahnaz

2014-01-01

400

Reproductive Cooperation Between Queens and Their Mated Workers: The Complex Life History of an ant With a Valuable Nest  

Microsoft Academic Search

The life history of Harpegnathos saltator is exceptional among ants because both queens and workers reproduce sexually. Recently mated queens start new colonies alone, but later some of the offspring workers also become inseminated and take over the egg-laying role. This alternation seems associated with the existence of very complex underground nests, which are designed to survive floods. Longevity of

Christian Peeters; Bert Holldobler

1995-01-01

401

Sentencing Juveniles to Life in Prison: The Reproduction of Juvenile Justice for Young Adolescents Charged with Murder  

ERIC Educational Resources Information Center

In "Roper v. Simmons," the U.S. Supreme Court determined that the sentencing of juveniles to death violated the constitutional amendment against cruel and unusual punishment. Similarly, the Court most recently decided that life without parole for non-homicide offenses is also unconstitutional ("Graham v. Florida," 2010). Part of the reason for the…

Singer, Simon I.

2011-01-01

402

Sentencing Juveniles to Life in Prison: The Reproduction of Juvenile Justice for Young Adolescents Charged With Murder  

Microsoft Academic Search

In Roper v. Simmons, the U.S. Supreme Court determined that the sentencing of juveniles to death violated the constitutional amendment against cruel and unusual punishment. Similarly, the Court most recently decided that life without parole for nonhomicide offenses is also unconstitutional (Graham v. Florida, 2010). Part of the reason for the Court’s decisions is the lack of consensus as to

Simon I. Singer

2011-01-01

403

Theoretical Contribution Age at first reproduction and probability of reproductive failure in women  

E-print Network

rights reserved. Keywords: Delayed reproduction; Sexual maturity; Life history; Lineage persistence 1Theoretical Contribution Age at first reproduction and probability of reproductive failure in women predicts a trade-off between fitness benefits and costs of delaying age at first reproduction (AFR

Lummaa, Virpi

404

A Perspective on the Importance of Reproductive Mode in Astrobiology  

Microsoft Academic Search

Reproduction is a vital characteristic of life, and sex is the most common reproductive mode in the eukaryotic world. Sex and reproduction are not necessarily linked mechanisms: Sexuality without reproduction exists, while several forms of asexual reproduction are known. The occurrence of sexuality itself is paradoxical, as it is very costly in evolutionary terms. Most of the hypotheses (more than

Karine Van Doninck; Isa Schön; Koen Martens

2003-01-01

405

Life history strategies in zooplankton communities: The significance of female gonad morphology and maturation types for the reproductive biology of marine calanoid copepods  

NASA Astrophysics Data System (ADS)

The present review addresses the reproductive strategies of marine calanoid copepods, as affected by their physiological preconditioning, and aims to enhance understanding of their adaptations to specific environmental conditions. Knowledge about oocyte development and internal gonad structure, especially in relation to feeding conditions, is essential for a complete understanding of the reproductive strategies of the copepods. Therefore, the foci of the review are to identify general patterns in oocyte and gonad development in calanoid copepod species from marine ecosystems worldwide and to elucidate the significance of gonad structures for reproductive strategies. Oogenesis is similar in all copepod species. During maturation, the morphology of the oocytes changes distinctly and, according to oocyte size and appearance of ooplasm and nucleus, five oocyte developmental stages are distinguished. In contrast, the gonad structure and its changes during the spawning cycle differ considerably among species, and these differences are related to specific reproductive traits. Four gonad morphology types can be distinguished: the Calanus-type, found in species from all over the world with distinctly different life history traits, is apparently most common in calanoid copepods. In this gonad type, most oocyte developmental stages are present simultaneously, and usually many oocytes mature synchronously, all of which are released in one clutch. The gonad structure allows frequent spawning and large clutches, hence, high egg production rates. This may be a preconditioning for exploiting seasonally high food supply. However, the Calanus-type was also found in species producing eggs at lower rates. In the diverticula of Pseudocalanus-type gonads, only two oocyte developmental stages are present and usually fewer oocytes mature synchronously. Accordingly, the egg production rate is generally lower as compared to the Calanus-type, and apparently only this gonad-type is structurally suitable for ovigerity. Species with Pseudocalanus-type gonads are present from polar seas to the tropics, some of them being key species. The Acartia-type was scarce, found in only one species, Acartia clausi. Here all oocyte developmental stages are present, including intermediate stages, but only a few oocytes mature synchronously and are released together. High spawning frequency compensates for the small clutches, and hence egg production rate may be as high as in Calanus-type gonads. In the Aetidius-type gonad, the total number of oocytes in the diverticula is low as is the number of oocytes maturing synchronously. Less is known about the reproductive biology of species with Aetidius-type gonads; however, their distribution and feeding patterns suggest that this type is common in species inhabiting environments of low food availability. The differences in gonad structures also lead to differences in the egg size:female size ratio, as the space available for each mature oocyte depends on the total number of oocytes. Independent from gonad-type, the eggs are relatively large in species in which the gonads contain only few oocytes, whereas small eggs are produced by species with gonads filled with many oocytes. Since all species carrying their eggs in external sacs until hatching (ovigerous species) have Pseudocalanus-type gonads, the scatter in their egg size:female size ratio is low. The broadcast spawning species are of all gonad-types, and consequently the scatter among them is high. A major factor affecting the timing and magnitude of spawning of calanoid copepods is the energy supply for gonad development. Therefore, part of the review elucidates the role of internal and external resources in fuelling egg production. In many species, freshly assimilated food is transferred into egg material within a short period of time, and clutch size and spawning frequency are the two parameters that allow adjustment of egg production to food availability and temperature. However, internal body reserves may also fuel oocyte development. The extent to which oogene

Niehoff, Barbara

2007-07-01

406

Computing minimum spanning trees efficiently  

Microsoft Academic Search

A ubiquitous problem in mathematical programming is the calculation of minimum spanning trees. Minimum spanning tree algorithms find application in such diverse areas as: least cost electrical wiring, minimum cost connecting communication and transportation networks, network reliability problems, minimum stress networks, clustering and numerical taxonomy, algorithms for solving traveling salesman problems, and multiterminal network flows. It is therefore important to

A. Kershenbaum; R. Van Slyke

1972-01-01

407

Nursing Process. Nursing: Basic Needs I. Nursing: Basic Needs II. Nursing through the Life Span. Entry into Professional Nursing. A Basic Course Outline (College Freshmen) for Nursing. A Four Year "2+2" Articulated Curriculum for the Occupation of Nursing.  

ERIC Educational Resources Information Center

This course outline provides materials for third-year courses in a "2+2" curriculum for the occupation of registered nurse. It is part of a planned and articulated 4-year curriculum that spans the junior and senior years of high school and the freshman and sophomore years of the postsecondary institution. Introductory materials include: the…

Maddox, Gaylon; And Others

408

Optimal life-history strategy differs between philopatric and dispersing individuals in a metapopulation.  

PubMed

Abundant empirical evidence for dispersal syndromes contrasts with the rarity of theoretical predictions about the evolution of life-history divergence between dispersing and philopatric individuals. We use an evolutionary model to predict optimal differences in age-specific reproductive effort between dispersing and philopatric individuals inhabiting the same metapopulation. In our model, only young individuals disperse, and their lifelong reproductive decisions are potentially affected by this initial event. Juvenile survival declines as density of adults and other juveniles increases. We assume a trade-off between reproduction and survival, so that different patterns of age-specific reproductive effort lead to different patterns of aging. We find that young immigrant mothers should allocate more resources to reproduction than young philopatric mothers, but these life-history differences vanish as immigrant and philopatric individuals get older. However, whether the higher early reproductive effort of immigrants results in higher fecundity depends on the postimmigration cost on fecundity. Dispersing individuals have consequently a shorter life span. Ultimately, these life-history differences are due to the fact that young dispersing individuals most often live in recently founded populations, where competition is relaxed and juvenile survival higher, favoring larger investment in offspring production at the expense of survival. PMID:24561601

Cotto, Olivier; Kubisch, Alexander; Ronce, Ophélie

2014-03-01

409

Harem stability and reproductive success of Misaki feral mares.  

PubMed

The stability of relationships between harem stallions and mares (consort relations) was investigated and the durations of inter partum intervals were determined in order to establish if there was any correlation between the stability of consort relation and reproductive success of mares in Misaki feral horses. Thirty-four mares were observed continuously for more than 5 years. The lifetime stability was 80-100% (mean 92.4%) for 16 mares, 60-79% (mean 70.4%) for 10 mares and 0-59% (mean 27.9%) for 8 mares. The continuous length (years) of specific consort relations was 2-10 years and was found to correlate significantly with lifetime stability. There was a significant positive correlation of lifetime stability with lifetime reproductive success for 34 mares observed, and the correlation was higher when the data of 8 wandering mares (<60% in lifetime stability) were omitted. The mean +/- s.d. delivery interval of 25 stable mares was 364.5 +/- 11.0 days, whereas that of 8 unstable mares and stable mares who changed stallions was 387.0 +/- 40.2 days. There was a significant difference between delivery intervals of stable and unstable mares. Significant correlations between the stability of consort relations and both the foaling rates and delivery intervals suggest that mares may obtain major reproductive advantages if they maintain long term and stable consort relations with a particular stallion throughout their reproductive life span. PMID:8654352

Kaseda, Y; Khalil, A M; Ogawa, H

1995-09-01

410

Reproductive Hazards  

MedlinePLUS

... and female reproductive systems play a role in pregnancy. Problems with these systems can affect fertility and ... a reproductive hazard can cause different effects during pregnancy, depending on when she is exposed. During the ...

411

Childhood Abuse is Associated with Adiposity in Mid-life Women: Possible Pathways through Trait Anger and Reproductive Hormones  

PubMed Central

Objective To examine the association between childhood abuse/neglect and central adiposity and obesity in a sample of 311 women (106 Black, 205 White) from the Pittsburgh site of the Study of Women's Health Across the Nation (SWAN). Methods SWAN included a baseline measurement of women in midlife (mean age = 45.7) and 8 follow-up visits during which waist circumference (WC) and body mass index (BMI) were measured. The Childhood Trauma Questionnaire retrospectively assessed emotional, physical, and sexual abuse and emotional and physical neglect in childhood. Results ANCOVA analyses showed that women with a history of any abuse/neglect, and specifically physical and sexual abuse, had significantly higher WC and BMI at baseline than women with no abuse history. A significant interaction between abuse and BMI showed that among women with BMI < 30, any abuse/neglect and certain subtypes of abuse predicted greater increases in WC over time. Additional analyses showed that Trait Anger scores and sex hormone-binding globulin (SHBG) attenuated cross-sectional relationships between abuse/neglect and WC and BMI. Conclusion This study suggests that abused/neglected women appear to have greater anger and lower levels of SHBG, which are associated with adiposity in mid-life. PMID:20064904

Midei, Aimee J.; Matthews, Karen A.; Bromberger, Joyce T.

2010-01-01

412

Primate energy expenditure and life history.  

PubMed

Humans and other primates are distinct among placental mammals in having exceptionally slow rates of growth, reproduction, and aging. Primates' slow life history schedules are generally thought to reflect an evolved strategy of allocating energy away from growth and reproduction and toward somatic investment, particularly to the development and maintenance of large brains. Here we examine an alternative explanation: that primates' slow life histories reflect low total energy expenditure (TEE) (kilocalories per day) relative to other placental mammals. We compared doubly labeled water measurements of TEE among 17 primate species with similar measures for other placental mammals. We found that primates use remarkably little energy each day, expending on average only 50% of the energy expected for a placental mammal of similar mass. Such large differences in TEE are not easily explained by differences in physical activity, and instead appear to reflect systemic metabolic adaptation for low energy expenditures in primates. Indeed, comparisons of wild and captive primate populations indicate similar levels of energy expenditure. Broad interspecific comparisons of growth, reproduction, and maximum life span indicate that primates' slow metabolic rates contribute to their characteristically slow life histories. PMID:24474770

Pontzer, Herman; Raichlen, David A; Gordon, Adam D; Schroepfer-Walker, Kara K; Hare, Brian; O'Neill, Matthew C; Muldoon, Kathleen M; Dunsworth, Holly M; Wood, Brian M; Isler, Karin; Burkart, Judith; Irwin, Mitchell; Shumaker, Robert W; Lonsdorf, Elizabeth V; Ross, Stephen R

2014-01-28

413

Conelike soap films spanning tetrahedra  

E-print Network

In this paper we provide the first examples of non-flat soap films proven to span tetrahedra. These are members of a continuous two parameter family of soap films with tetrahedral boundaries. Of particular interest is a two parameter subfamily where each spanning soap film has the property that two minimal surfaces meet along an edge of the boundary at an angle greater than 120 degrees.

Huff, Robert

2008-01-01

414

Animal Reproduction  

NSDL National Science Digital Library

From Dr. Michael Gregory of Clinton Community College, this site is a concise overview of animal reproduction. The site addresses important aspects of sexual and asexual reproduction, the male and female reproductive systems, fertilization, and the importance of hormones. Visitors to the site will find diagrams outlining biological processes especially helpful.

Gregory, Michael

415

Asexual Reproduction  

NSDL National Science Digital Library

From the author of Kimball's Biology textbook, this online chapter presents modes of asexual reproduction in plants and animals. Asexual reproduction in plants includes stems, leaves, roots, plant propagation and apomixis, whereas the animal section includes budding, fragmentation and parthenogenesis. The chapter is supported with a general discussion about the advantages and disadvantages of asexual reproduction.

John W. Kimball

416

Studies on the life cycle and reproduction of the parasitic amphipod Hyperia galba in the North Sea  

NASA Astrophysics Data System (ADS)

The structure of a Hyperia galba population, and its seasonal fluctuations were studied in the waters of the German Bight around the island of Helgoland over a period of two years (1984 and 1985). A distinct seasonal periodicity in the distribution pattern of this amphipod was recorded. During summer, when its hosts—the scyphomedusae Aurelia aurita, Chrysaora hysoscella, Rhizostoma pulmo, Cyanea capillata and Cyanea lamarckii—occur in large numbers, supplying shelter and food, a population explosion of H. galba can be observed. It is caused primarily by the relatively high fecundity of H. galba which greatly exceeds that of other amphipods: a maximum of 456 eggs was observed. The postembryonic development is completed in the medusae infested; only then are the young able to swim and search for a new host. The smallest fréely-swimming hyperians obtained from plankton samples were 2.6 mm in body size. The size classes observed as well as moult increment and moulting frequencies in relation to different temperatures suggest that two generations are developed per year: a rapidly growing generation in summer and a slower growing generation in winter that shifts to a benthic mode of life and hibernation. For short periods, adult hyperians may become attached to zooplankters other than scyphomedusae. However, when releasing the progeny, they are dependent on the presence of these coelenterates. Apparently, a host specificity does not exist. During daytime, the hyperians seem to avoid a host change; only 0.2% of all the individuals sampled in the plankton during the day were not associated with medusae. The heavy infestation of medusae by this crustacean leads to a weakening and a progressive breakdown of these important predators on fish larvae. H. galba occupies a specific position in the marine food web which is discussed in detail.

Dittrich, Birgit

1988-03-01

417

Male Reproductive System.  

ERIC Educational Resources Information Center

This autoinstructional lesson deals with the study of the human body with emphasis on the life process of reproduction. It is a learning activity included in high school biology or health education classes. The behavioral objectives are listed and the equipment and materials needed to help the student gain these objectives are also included in the…

Turkington, B. A.

418

Date of eclosion modulates longevity: insights across dietary-restriction gradients and female reproduction in the mexfly Anastrepha ludens  

PubMed Central

We use unique experimental data on daily reproduction and survival of individual fruit flies from eight cohorts eclosed at different dates in 2004 and 2005 who were treated with varying proportions of sugar and yeast and subject to different caloric restrictions (CR). We investigate the relationship between eclosion date and longevity across diets and reproduction in Anastrepha ludens. We show that eclosion date can be associated with uncontrolled external or internal factor(s) which can modulate longevity of males and females independently of diet and reproduction to the extent similar to the effect of diet on longevity. The effect of diet manipulation on longevity is sensitive to date of eclosion with the role of CR in life extension ranging from beneficial to harmful. Interaction of date of eclosion with compositional changes of sugar and yeast but not with CR is responsible for life extension. Highly protein-enriched diets reliably maximize reproduction but not life span. Decreased longevity of flies treated with high-protein diets may be associated with harmful consequences of protein ingestion but is unlikely a result of high reproduction rates. We present evidence for the presence of two frailty-sensitive weakly interacting mechanisms of longevity in female flies associated with differences in predisposed fitness. PMID:19716408

Kulminski, Alexander M.; Molleman, Freerk; Culminskaya, Irina V.; Arbeev, Konstantin G.; Ukraintseva, Svetlana V.; Carey, James R.; Yashin, Anatoli I.

2009-01-01

419

Minimum Spanning Trees Suggested Reading: Chapter 23.  

E-print Network

Minimum Spanning Trees CSE 680 Suggested Reading: Chapter 23. 1 Greedy Method Optimization Problem best at this moment 1 #12;2 Minimum Spanning Trees · Spanning tree: A spanning tree of a connected = (V, E), find a span- ning tree of minimum cost. · Assume V = {1, 2, . . . , n}. 2 #12;3 Prim

Lai, Ten-Hwang "Steve"

420

Minimum Spanning Trees Suggested Reading: Chapter 23.  

E-print Network

Minimum Spanning Trees CSE 2331 Suggested Reading: Chapter 23. 1 Greedy Method Optimization Problem best at this moment 1 #12;2 Minimum Spanning Trees · Spanning tree: A spanning tree of a connected = (V, E), find a span- ning tree of minimum cost. · Assume V = {1, 2, . . . , n}. 2 #12;3 Prim

Lai, Ten-Hwang "Steve"

421

Social Rank, Stress, Fitness, and Life Expectancy in Wild Rabbits  

NASA Astrophysics Data System (ADS)

Wild rabbits of the two sexes have separate linear rank orders, which are established and maintained by intensive fights. The social rank of individuals strongly influence their fitness: males and females that gain a high social rank, at least at the outset of their second breeding season, have a much higher lifetime fitness than subordinate individuals. This is because of two separate factors: a much higher fecundity and annual reproductive success and a 50% longer reproductive life span. These results are in contrast to the view in evolutionary biology that current reproduction can be increased only at the expense of future survival and/or fecundity. These concepts entail higher physiological costs in high-ranking mammals, which is not supported by our data: In wild rabbits the physiological costs of social positions are caused predominantly by differential psychosocial stress responses that are much lower in high-ranking than in low-ranking individuals.

von Holst, Dietrich; Hutzelmeyer, Hans; Kaetzke, Paul; Khaschei, Martin; Schönheiter, Ronald

422

Temporal variability in the life history and reproductive biology of female dugongs in Torres Strait: The likely role of sea grass dieback  

NASA Astrophysics Data System (ADS)

The extensive sea grass meadows in Torres Strait enable it to be a globally important habitat for the dugong, Dugong dugon, a marine mammal of cultural and dietary significance to Torres Strait Islanders and the basis for the substantial island-based fishery in the Torres Strait Protected Zone. Torres Strait sea grass communities are subjected to episodic diebacks which are now believed to be largely natural events. Information on dugong life history was obtained from specimens obtained from female dugongs as they were butchered for food by Indigenous hunters at two major dugong hunting communities in Torres Strait: Daru (9.04°S, 143.21°E) in 1978-1982 (a time of sea grass dieback and recovery) and Mabuiag Island (9.95°S, 142.15°E) in 1997-1999 (when sea grasses were abundant). Dugongs sampled in 1997-1999 had their first calf at younger ages (minimum of 6 cf. 10 years), and more frequently (interbirth interval based on all possible pregnancies 2.6±0.4 (S.E.) yr cf. 5.8±1.0 yr) than the dugongs sampled in 1978-1982. Pregnancy rates increased monotonically during 1978-1982, coincident with sea grass recovery. The age distribution of the female dugongs collected in 1997-1999 also suggested a low birth rate between 1973 and 1983 and/or or a high level of mortality for animals born during this period. These results add to the evidence from other regions that the life history and reproductive rate of female dugongs are adversely affected by sea grass loss, the effect of which cannot be separated from a possible density-dependent response to changes in dugong population size. Many green turtles in Torres Strait were also in poor body condition coincident with the 1970s sea grass dieback. The impacts of future sea grass diebacks need to be anticipated when management options for the traditional Torres Strait fisheries for dugongs and green turtles are evaluated.

Marsh, Helene; Kwan, Donna

2008-09-01

423

Variation in the reproductive rate of bats  

Microsoft Academic Search

In many respects, bats have relatively slow life histories. However, the reproductive rate of bats (i.e., the proportion of females that reproduce in any breeding season) has not been critically examined. We compiled data on the reproductive rates of bats to test predictions based on life-history theory. Among 257 samples from 103 species, re - productive rate varied considerably and

Robert M. R. Barclay; Joel Ulmer; Cameron J. A. MacKenzie; Megan S. Thompson; Leif Olson; Julianne McCool; Elvie Cropley; Graeme Poll

2004-01-01

424

Animal Reproduction  

NSDL National Science Digital Library

This Topic in Depth takes a look at organizations and educational websites concerned with reproduction in humans and other animals. The Society for the Study of Reproduction (SSR) "is an association of scientists and physicians interested in research in reproduction. Some members are engaged in basic or applied research, while others perform clinical practice." The SSR website (1) contains downloadable copies of the SSR Newsletter; position statements; and information about meetings, awards, and the organization. The Society for Reproduction and Fertility (SRF) "is open to scientists and students worldwide, who work on any aspect of reproductive biology or fertility in man and animals." The SRF website (2) contains sections regarding News, Events, Jobs, Honours, and Grants. SRF makes downloadable copies of its newsletter available as well. The primary aim of the European Society of Human Reproduction & Embryology (ESHRE) "is to promote interest in, and understanding of, reproductive biology and medicine. It does this through facilitating research and subsequent dissemination of research findings in human reproduction and embryology to the general public, scientists, clinicians and patient associations; it also works to inform politicians and policy makers throughout Europe." The ESHRE site (3) contains information about activities, membership, publications, special interest groups, and jobs. The primary function of the Centre for Reproductive Biology in Uppsala (CRU) "is to increase the knowledge about reproduction in animals and humans by applying a more comprehensive view on reproductive biology." CRU is composed of scientists from both Uppsala University and the Swedish University of Agricultural Science. The CRU site (4) contains information about a number of publications, and contact information for CRU members. The Population Council is a nonprofit "organization that conducts biomedical, social science, and public health research." The "Council's reproductive biology and immunology program undertakes fundamental research in the reproductive sciences and immunological processes related to sexually transmitted infections, particularly HIV." This website (5) provides information about different aspects of the research program including Germ Cell Dynamics, Sperm Maturation, and Physiology of Sertoli Cells. From Dr. Michael Gregory of Clinton Community College, the next site (6) is a concise overview of animal reproduction which addresses important aspects of sexual reproduction, and male and female reproductive systems. The final site (7) contains lecture notes regarding avian reproduction from Dr. Gary Ritchison's Ornithology course at Eastern Kentucky University. The lecture notes are interspersed with some especially nice images and diagrams.

425

DEP and AFO Regulate Reproductive Habit in Rice  

Microsoft Academic Search

Sexual reproduction is essential for the life cycle of most angiosperms. However, pseudovivipary is an important reproductive strategy in some grasses. In this mode of reproduction, asexual propagules are produced in place of sexual reproductive structures. However, the molecular mechanism of pseudovivipary still remains a mystery. In this work, we found three naturally occurring mutants in rice, namely, phoenix (pho),

Kejian Wang; Ding Tang; Lilan Hong; Wenying Xu; Jian Huang; Ming Li; Minghong Gu; Yongbiao Xue; Zhukuan Cheng

2010-01-01

426

Spanning Trees A spanning tree of a simple graph G is a sub-  

E-print Network

return T Minimum Spanning Trees A minimum spanning tree of a weighted simple graph G is a spanning tree1 Spanning Trees A spanning tree of a simple graph G is a sub- graph that is a tree and contains every vertex. A simple graph is connected if and only if it has a spanning tree. Depth-first search

Bylander, Tom

427

Animal Reproduction  

NSDL National Science Digital Library

What animals abandon their offspring? Find out this and more as you explore reproduction in the animal world. Did you know that all animals must reproduce to survive? In this project you will be learning some interesting facts about reproduction in animals. After you have some background information you will have a chance to select 3 animals and complete a chart on reproduction. TASK: Day 1 ...

Mrs. Joggerst

2008-03-30

428

The optimum spanning catenary cable  

NASA Astrophysics Data System (ADS)

A heavy cable spans two points in space. There exists an optimum cable length such that the maximum tension is minimized. If the two end points are at the same level, the optimum length is 1.258 times the distance between the ends. The optimum lengths for end points of different heights are also found.

Wang, C. Y.

2015-03-01

429

Hibernation is associated with increased survival and the evolution of slow life histories among mammals  

PubMed Central

Survival probability is predicted to underlie the evolution of life histories along a slow–fast continuum. Hibernation allows a diverse range of small mammals to exhibit seasonal dormancy, which might increase survival and consequently be associated with relatively slow life histories. We used phylogenetically informed GLS models to test for an effect of hibernation on seasonal and annual survival, and on key attributes of life histories among mammals. Monthly survival was in most cases higher during hibernation compared with the active season, probably because inactivity minimizes predation. Hibernators also have approximately 15 per cent higher annual survival than similar sized non-hibernating species. As predicted, we found an effect of hibernation on the relationships between life history attributes and body mass: small hibernating mammals generally have longer maximum life spans (50% greater for a 50 g species), reproduce at slower rates, mature at older ages and have longer generation times compared with similar-sized non-hibernators. In accordance with evolutionary theories, however, hibernating species do not have longer life spans than non-hibernators with similar survival rates, nor do they have lower reproductive rates than non-hibernators with similar maximum life spans. Thus, our combined results suggest that (i) hibernation is associated with high rates of overwinter and annual survival, and (ii) an increase in survival in hibernating species is linked with the coevolution of traits indicative of relatively slow life histories. PMID:21450735

Turbill, Christopher; Bieber, Claudia; Ruf, Thomas

2011-01-01

430

The SPAN cookbook: A practical guide to accessing SPAN  

NASA Technical Reports Server (NTRS)

This is a manual for remote users who wish to send electronic mail messages from the Space Physics Analysis Network (SPAN) to scientific colleagues on other computer networks and vice versa. In several instances more than one gateway has been included for the same network. Users are provided with an introduction to each network listed with helpful details about accessing the system and mail syntax examples. Also included is information on file transfers, remote logins, and help telephone numbers.

Mason, Stephanie; Tencati, Ronald D.; Stern, David M.; Capps, Kimberly D.; Dorman, Gary; Peters, David J.

1990-01-01

431

Phenotypic plasticity of life history characteristics: quantitative analysis of delayed reproduction of green foxtail (Setaria viridis) in the Songnen Plain of China.  

PubMed

Green foxtail (Setaria viridis L.) is a common weed species in temperate regions. Research on the effect of delayed reproduction on the phenotypic plasticity and regularity of the vegetative and reproductive growth is of vital significance for understanding population regulation and control of the weed in the growing season. Green foxtail seeds were sown every 10 days from 25 June to 24 August of 2004. The growth and production metrics were measured via harvesting tufts and statistical analysis was carried out. The results showed that the reproductive tillers, seed number, seed biomass and one thousand-seed weight of plants at the first sowing (25 June) approximately increased 28.8, 7 827.0, 1 104.0 and 12.3 times compared with that at the last sowing (24 August), respectively. Total tillers, reproductive tillers and height increased linearly as the reproductive period delayed, however, biomass increased exponentially. Quadratic equations best explained the relationships between the delayed reproductive period and seed number, inflorescence length, one thousand-seed weight, seed biomass. Based on the quantity and quality of seed production, weeding young seedlings emerging before July can be the most effective weed-control strategy in the Songnen Plain. PMID:18713403

Li, Hai-Yan; Yang, Yun-Fei

2008-06-01

432

99. Reproduction from glass plate negative (Modjeski and Masters office, ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

99. Reproduction from glass plate negative (Modjeski and Masters office, Modjeski Collection, No. 183, May 6, 1908) SETTING CENTER CASTING - Burlington Northern Railroad Bridge, Spanning Willamette River at River Mile 6.9, Portland, Multnomah County, OR

433

92. Reproduction from glass plate negative (Modjeski and Masters office, ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

92. Reproduction from glass plate negative (Modjeski and Masters office, Modjeski Collection No. 70, December 24, 1906) CAISSON No. 2 - Burlington Northern Railroad Bridge, Spanning Willamette River at River Mile 6.9, Portland, Multnomah County, OR

434

96. Reproduction from glass plate negative (Modjeski and Masters office, ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

96. Reproduction from glass plate negative (Modjeski and Masters office, Modjeski Collection, No. 161, March 2, 1908) DERRICK AT PIER 2 - Burlington Northern Railroad Bridge, Spanning Willamette River at River Mile 6.9, Portland, Multnomah County, OR

435

90. Reproduction from glass plate negative (Modjeski and Masters office, ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

90. Reproduction from glass plate negative (Modjeski and Masters office, Modjeski Collection, No. 26, August 24, 1906) INTERIOR OF ENGINE ROOM, PRESSURE BARGE - Burlington Northern Railroad Bridge, Spanning Willamette River at River Mile 6.9, Portland, Multnomah County, OR

436

94. Reproduction from glass plate negative (Modjeski and Masters office, ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

94. Reproduction from glass plate negative (Modjeski and Masters office, Modjeski Collection, No. 106, May 13, 1907) CAISSON No. 3 - Burlington Northern Railroad Bridge, Spanning Willamette River at River Mile 6.9, Portland, Multnomah County, OR

437

93. Reproduction from glass plate negative (Modjeski and Masters office, ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

93. Reproduction from glass plate negative (Modjeski and Masters office, Modjeski Collection, No. 92, February 9, 1907) CAISSON No. 3 JUST BEFORE LAUNCHING - Burlington Northern Railroad Bridge, Spanning Willamette River at River Mile 6.9, Portland, Multnomah County, OR

438

88. Reproduction from glass plate negative (original in Modjeski and ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

88. Reproduction from glass plate negative (original in Modjeski and Masters office, Harrisburg, Pennsylvania, Modjeski Collection, No. 4, not dated) LOOKING DOWNSTREAM - Burlington Northern Railroad Bridge, Spanning Willamette River at River Mile 6.9, Portland, Multnomah County, OR

439

91. Reproduction from glass plate negative (Modjeski and Masters office, ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

91. Reproduction from glass plate negative (Modjeski and Masters office, Modjeski Collection, No. 44, October 13, 1906) SANDBAGGING PIER No. 4 - Burlington Northern Railroad Bridge, Spanning Willamette River at River Mile 6.9, Portland, Multnomah County, OR

440

On the Euclidean Minimum Spanning Tree Problem  

E-print Network

On the Euclidean Minimum Spanning Tree Problem Sanguthevar Rajasekaran Dept. of CSE, University of Connecticut Storrs, CT 06269 Abstract Given a weighted graph G(V, E), a minimum spanning tree for G can a minimum spanning tree for this graph is known as the Euclidean minimum spanning tree problem (EMSTP

Rajasekaran, Sanguthevar