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Sample records for chronological life span

  1. Two-carbon metabolites, polyphenols and vitamins influence yeast chronological life span in winemaking conditions

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    Orozco Helena

    2012-08-01

    Full Text Available Abstract Background Viability in a non dividing state is referred to as chronological life span (CLS. Most grape juice fermentation happens when Saccharomyces cerevisiae yeast cells have stopped dividing; therefore, CLS is an important factor toward winemaking success. Results We have studied both the physical and chemical determinants influencing yeast CLS. Low pH and heat shorten the maximum wine yeast life span, while hyperosmotic shock extends it. Ethanol plays an important negative role in aging under winemaking conditions, but additional metabolites produced by fermentative metabolism, such as acetaldehyde and acetate, have also a strong impact on longevity. Grape polyphenols quercetin and resveratrol have negative impacts on CLS under winemaking conditions, an unexpected behavior for these potential anti-oxidants. We observed that quercetin inhibits alcohol and aldehyde dehydrogenase activities, and that resveratrol performs a pro-oxidant role during grape juice fermentation. Vitamins nicotinic acid and nicotinamide are precursors of NAD+, and their addition reduces mean longevity during fermentation, suggesting a metabolic unbalance negative for CLS. Moreover, vitamin mix supplementation at the end of fermentation shortens CLS and enhances cell lysis, while amino acids increase life span. Conclusions Wine S. cerevisiae strains are able to sense changes in the environmental conditions and adapt their longevity to them. Yeast death is influenced by the conditions present at the end of wine fermentation, particularly by the concentration of two-carbon metabolites produced by the fermentative metabolism, such as ethanol, acetic acid and acetaldehyde, and also by the grape juice composition, particularly its vitamin content.

  2. Interference of aging media on the assessment of yeast chronological life span by propidium iodide staining.

    Science.gov (United States)

    Pereira, Clara; Saraiva, Lucília

    2013-01-01

    An increasing number of researchers are using the Saccharomyces cerevisiae chronological aging model to gain insight into the post-mitotic cellular aging. Recently, an alternative approach to the traditional cellular viability assay by colony-forming unit (CFU) counts, based on the propidium iodide (PI) staining combined with flow cytometry (PI-FCM), was proposed for the assessment of yeast chronological aging. Since the chronological aging assessment shows variations particularly concerning the aging media, in this work, the influence of the most common aging media (exhausted media or water) on the assessment of chronological aging by PI staining was studied. Our results show that this methodology is highly affected by the aging media. Indeed, a correlation between CFU counts and the percentage of PI-stained cells is only achieved with the exhausted media. As such, the assessment of yeast chronological aging by PI-FCM water should not be used.

  3. Mitochondrial dysfunction increases oxidative stress and decreases chronological life span in fission yeast.

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    Alice Zuin

    Full Text Available BACKGROUND: Oxidative stress is a probable cause of aging and associated diseases. Reactive oxygen species (ROS originate mainly from endogenous sources, namely the mitochondria. METHODOLOGY/PRINCIPAL FINDINGS: We analyzed the effect of aerobic metabolism on oxidative damage in Schizosaccharomyces pombe by global mapping of those genes that are required for growth on both respiratory-proficient media and hydrogen-peroxide-containing fermentable media. Out of a collection of approximately 2700 haploid yeast deletion mutants, 51 were sensitive to both conditions and 19 of these were related to mitochondrial function. Twelve deletion mutants lacked components of the electron transport chain. The growth defects of these mutants can be alleviated by the addition of antioxidants, which points to intrinsic oxidative stress as the origin of the phenotypes observed. These respiration-deficient mutants display elevated steady-state levels of ROS, probably due to enhanced electron leakage from their defective transport chains, which compromises the viability of chronologically-aged cells. CONCLUSION/SIGNIFICANCE: Individual mitochondrial dysfunctions have often been described as the cause of diseases or aging, and our global characterization emphasizes the primacy of oxidative stress in the etiology of such processes.

  4. Caloric restriction restores the chronological life span of the Goa1 null mutant of Candida albicans in spite of high cell levels of ROS.

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    Chen, Hui; Calderone, Richard; Sun, Nuo; Wang, Yun; Li, Dongmei

    2012-12-01

    The Candida albicans Goa1p is required for mitochondrial functions. In a strain lacking GOA1 (GOA31), respiration, mitochondrial membrane potential, complex I (CI) activity of the electron transport chain, and ATP synthesis are significantly decreased. A shortened chronological life span (CLS) of GOA31 occurs in 2% glucose that is associated with an increase in cell reactive oxidant species (ROS) and apoptosis. We now show that caloric restriction (CR) in media containing 0.5% glucose instead of 2% glucose-SC extends the CLS to the level of parental and gene-reconstituted strains. Paradoxically, ROS levels in GOA31 far exceed those of control strains in 0.5% glucose and, as a consequence, increased lipid peroxidation occurs even though CLS is restored. Microarray analysis was used to characterize transcriptional changes during CR in GOA31. We found that CR shifts cells of all strains to a non-glucose carbon metabolism (β-oxidation). Our model of ROS formation in GOA31 follows the paradigm that the generation of oxygen radicals from β-oxidation of cell lipids via FADH(2) (CII) and NADH (CI) creates an unfavorable cellular FADH(2)/NADH ratio that causes a transient overload in CII activity resulting in excess free cell radicals. In GOA31 the CI and peroxisomal dysfunctions increase the levels of ROS compared to control strains. Recovery from high levels of ROS may be associated with an increase in iron and sugar transporters, as well as an anti-stress response that includes the SOD1 and GPX1. Thus, CR creates a favorable growth environment, but cells of GOA31 must overcome a high but transient ROS production.

  5. Life Span Developmental Approach

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    Ali Eryilmaz

    2011-03-01

    Full Text Available The Life Span Developmental Approach examines development of individuals which occurs from birth to death. Life span developmental approach is a multi-disciplinary approach related with disciplines like psychology, psychiatry, sociology, anthropology and geriatrics that indicates the fact that development is not completed in adulthood, it continues during the life course. Development is a complex process that consists of dying and death. This approach carefully investigates the development of individuals with respect to developmental stages. This developmental approach suggests that scientific disciplines should not explain developmental facts only with age changes. Along with aging, cognitive, biological, and socioemotional development throughout life should also be considered to provide a reasonable and acceptable context, guideposts, and reasonable expectations for the person. There are three important subjects whom life span developmental approach deals with. These are nature vs nurture, continuity vs discontinuity, and change vs stability. Researchers using life span developmental approach gather and produce knowledge on these three most important domains of individual development with their unique scientific methodology.

  6. Genomic instability is associated with natural life span variation in Saccharomyces cerevisiae.

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    Hong Qin

    Full Text Available Increasing genomic instability is associated with aging in eukaryotes, but the connection between genomic instability and natural variation in life span is unknown. We have quantified chronological life span and loss-of-heterozygosity (LOH in 11 natural isolates of Saccharomyces cerevisiae. We show that genomic instability increases and mitotic asymmetry breaks down during chronological aging. The age-dependent increase of genomic instability generally lags behind the drop of viability and this delay accounts for approximately 50% of the observed natural variation of replicative life span in these yeast isolates. We conclude that the abilities of yeast strains to tolerate genomic instability co-vary with their replicative life spans. To the best of our knowledge, this is the first quantitative evidence that demonstrates a link between genomic instability and natural variation in life span.

  7. Life span of the biosphere

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    Lovelock, J. E.; Whitfield, M.

    1982-04-01

    Since main sequence stars appear to increase their burning rate as they age, the sun may be thought to have increased its output by 30% since the earth's origin 4.5 billion years ago. Due to the requirement for some means of planetary thermostasis in the maintenance of an equable climate since life began, possible links are considered between the biological, Gaia hypothesis of Lovelock and Margulis (1974) for climate control, and Walker et al's (in press) model of automatic thermostasis, in which the abundance of such atmospheric greenhouse gases as CO2 adjusts to resist the warming tendency of the increased solar flux. It is concluded that, since atmospheric CO2 is now close to its partial pressure lower limit, the biosphere will on a geological time-scale be soon exposed, without protection, to the predicted solar luminosity increases.

  8. Friendship and adaption across the life span

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    Hartup, W.W.; Stevens, N.L.

    1999-01-01

    Friends foster self-esteem and a sense of well-being, socialize one another, and support one another in coping with developmental transitions and life stress. Friends engage in different activities with one another across the life span, but friendship is conceived similarly by children and adults. F

  9. Visual Search Across the Life Span

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    Hommel, Bernhard; Li, Karen Z. H.; Li, Shu-Chen

    2004-01-01

    Gains and losses in visual search were studied across the life span in a representative sample of 298 individuals from 6 to 89 years of age. Participants searched for single-feature and conjunction targets of high or low eccentricity. Search was substantially slowed early and late in life, age gradients were more pronounced in conjunction than in…

  10. Career development: a life span issue.

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    Sterns, H L; Dorsett, J G

    1994-01-01

    One of the challenges for individuals pursuing a career throughout their life span is how to maintain a high level of professional competence. As the composition of the workforce changes, and new technologies are developed, workers are faced with changing job demands and pressures. A major issue for the 1990s is how long a worker's skills will remain current. With rapid technological changes, workers may find it necessary to update continually their knowledge, skills, and abilities or risk becoming obsolete. Factors such as individuals' motivation and attitudes and organizational climate can contribute to choices regarding career development. Current research on the factors that contribute to career development activities is reviewed, along with the impact of multiple career transitions throughout the life span. Interventions such as retraining and outplacement, which allow individuals in later life to continue work, change jobs, and further develop their careers, are also discussed.

  11. Identifying sexual differentiation genes that affect Drosophila life span

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    Tower John

    2009-12-01

    Full Text Available Abstract 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

  12. Life Span and Resiliency Theory: A Critical Review

    OpenAIRE

    Alexa Smith-Osborne

    2007-01-01

    Theories of life span development describe human growth and change over the life cycle (Robbins, Chatterjee, & Canda, 2006). Major types of developmental theories include biological, psychodynamic, behavioral, and social learning, cognitive, moral, and spiritual, and those influenced by systems, empowerment, and conflict theory. Life span development theories commonly focus on ontogenesis and sequential mastery of skills, tasks, and abilities. Social work scholars have pointed out that a limi...

  13. The impact of invisible illness on identity and contextual age across the life span.

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    Kundrat, Amanda L; Nussbaum, Jon F

    2003-01-01

    This study explored the impact invisible illness has on identity, specifically contextual age, throughout the life span. It was grounded in the assumption that an individual's identity is formed through communicative interaction. Using social identity theory (Tajfel & Turner, 1986) as a framework, individuals' identities after disclosure of invisible illness were explored. Rubin and Rubin's (1986) Contextual Age Questionnaire was used to determine self-perceived as well as other-perceived contextual age. Invisibly ill individuals reported significantly "higher" contextual age scores than did same chronologically aged, matched non-ill individuals. In addition, the friends of invisibly ill individuals reported "higher" contextual age scores for the invisibly ill individuals than the self-reported scores of the same chronologically aged non-ill individuals. Interviews further revealed that illness instilled insight and that disclosure of illness provoked comments from others that led invisibly ill individuals to identify with older individuals. Future directions and limitations of this study are also discussed.

  14. IS LIFE-SPAN UNDER OUR CONTROL??

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    Parle Milind

    2011-01-01

    Full Text Available With each passing day, we age. Our body gets flooded with unwanted and deleterious elements, our cells lose their ability to divide, our nervous, endocrine and immune systems weaken with advancing age. Sagging skin, wrinkled face, graying hair, loss of muscle strength, reduced reflexes, low energy levels, increasing fat, faulty memory (dementia, weak immunity, impaired vision, defective hearing, decreased libido, cardiovascular problems and neurodegenerative disorders (like Parkinsonism and Alzheimer’s disease are the characteristic features of ageing. Leading a disease free, long life (longevity has been a dream of mankind since the arrival of human race on the planet Earth. We can not reverse the ageing process, but the features associated with ageing can be delayed in order to improve the quality of life. The present review article focuses on different theories of ageing and the anti-ageing effects of Green tea, Garlic, Turmeric, Ashwagandha, Tomato, Anwala, Ginger, Aloe and Tulsi.

  15. A CRTCal link between energy and life span.

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    Brunet, Anne

    2011-04-01

    Cutting down calories prolongs life, but how this works remains largely unknown. A recent study in Nature (Mair et al., 2011) shows that life span extension triggered by the energy-sensing protein kinase AMPK is mediated by an evolutionarily conserved transcriptional circuit involving CRTC-1 and CREB.

  16. Paternal smoking habits affect the reproductive life span of daughters

    DEFF Research Database (Denmark)

    Fukuda, Misao; Fukuda, Kiyomi; Shimizu, Takashi

    2011-01-01

    The present study assessed whether the smoking habits of fathers around the time of conception affected the period in which daughters experienced menstrual cycles (i.e., the reproductive life span). The study revealed that the smoking habits of the farther shortened the daughters' reproductive life...

  17. Radiation effects on life span in Caenorhabditis elegans

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    Johnson, T.E.; Hartman, P.S.

    1988-09-01

    Wild-type and radiation-sensitive (Rad) mutants of Caenorhabditis elegans were irradiated using a /sup 137/Cs source (2.7 krads/min.) at several developmental stages and subsequently monitored for life span. Acute doses of radiation ranged from 1 krad to 300 krads. All stages required doses above 100 krads to reduce mean life span. Dauers and third stage larvae were more sensitive, and 8-day-old adults were the most resistant. Occasional statistically significant but nonrepeatable increases in survival were observed after intermediate levels of irradiation (10-30 krads). Unirradiated rad-4 and rad-7 had life spans similar to wild-type; all others had a significant reduction in survival. The mutants were about as sensitive as wild-type to the effects of ionizing radiation including occasional moderate life span extensions at intermediate doses. We conclude that the moderate life span extensions sometimes observed after irradiation are likely to be mediated by a means other than the induction of DNA repair enzymes.

  18. Life Span and Resiliency Theory: A Critical Review

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    Alexa Smith-Osborne

    2007-05-01

    Full Text Available Theories of life span development describe human growth and change over the life cycle (Robbins, Chatterjee, & Canda, 2006. Major types of developmental theories include biological, psychodynamic, behavioral, and social learning, cognitive, moral, and spiritual, and those influenced by systems, empowerment, and conflict theory. Life span development theories commonly focus on ontogenesis and sequential mastery of skills, tasks, and abilities. Social work scholars have pointed out that a limitation of life span and other developmental theory is lack of attention to resilience (Greene, 2007; Robbins et al., 1998. The concept of resilience was developed to “describe relative resistance to psychosocial risk experiences” (Rutter, 1999b, p. 119. Longitudinal studies focused on typical and atypical child development informed theory formulation in developmental psychopathology (Garmezy & Rutter, 1983; Luthar, Cichetti,& Becker, 2000 and in an evolving resilience model (Richardson, 2002; Werner & Smith, 1992. Research on resilience has found a positive relationship between a number of individual traits and contextual variables and resistance to a variety of risk factors among children and adolescents. More recently, resilience research has examined the operation of these same factors in the young adult, middle-age, and elder life stages. This article examines the historical and conceptual progression of the two developmental theories—life span and resiliency—and discusses their application to social work practice and education in human behavior in the social environment.

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

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    Briggs, Michele Kielty; Dixon, Andrea L.

    2013-01-01

    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…

  20. Life spans of planktonic foraminifers: New sight through sediment traps

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    Nigam, R.; Saraswat, R.; Mazumder, A

    in culture experiments and range from a few days to a few weeks, varying widely. Here the use of sediment trap technique is proposed to get much better estimates of life spans of planktonic foraminifers. On the basis of sediment trap results...

  1. DIRECT SELECTION ON LIFE-SPAN IN DROSOPHILA-MELANOGASTER

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    ZWAAN, B; BIJLSMA, R; HOEKSTRA, RE

    1995-01-01

    An important issue in the study of the evolution of aging in Drosophila melanogaster is whether decreased early fecundity is inextricably coupled with increased life span in selection experiments on age at reproduction. Here, this problem has been tackled using an experimental design in which select

  2. Neuromodulation of Behavioral and Cognitive Development across the Life Span

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    Li, Shu-Chen

    2012-01-01

    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…

  3. Orion: a glimpse of hope in life span extension?

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    Muradian, K; Bondar, V; Bezrukov, V; Zhukovsky, O; Polyakov, V; Utko, N

    2010-01-01

    Orion is a multicomponent drug based on derivatives of taurocholic acid and several other compounds. Application of Orion into the feeding medium of Drosophila melanogaster resulted in increased life span and survival at stressful conditions. Two paradoxical features of the drug should be stressed: The "age-threshold" (life span extension was observed only when the drug was applied starting from the second half of life) and induction of "centenarian" flies (older 100 days). Orion enhanced survival at heat shock (38 degrees C) and acidic (pH = 1.6) or alkaline (pH = 11.8) feeding mediums, but not at oxidative stresses modeled by 100% oxygen or application of hydrogen peroxide (H(2)O(2)).

  4. Rapamycin extends life- and health span because it slows aging.

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    Blagosklonny, Mikhail V

    2013-08-01

    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.

  5. Homeless Aging Veterans in Transition: A Life-Span Perspective

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    Carla J. Thompson

    2013-01-01

    Full Text Available 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.

  6. The social context of managing diabetes across the life span.

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    Wiebe, Deborah J; Helgeson, Vicki; Berg, Cynthia A

    2016-10-01

    Diabetes self-management is crucial to maintaining quality of life and preventing long-term complications, and it occurs daily in the context of close interpersonal relationships. This article examines how social relationships are central to meeting the complex demands of managing Type I and Type 2 diabetes across the life span. The social context of diabetes management includes multiple resources, including family (parents, spouses), peers, romantic partners, and health care providers. We discuss how these social resources change across the life span, focusing on childhood and adolescence, emerging adulthood, and adulthood and aging. We review how diabetes both affects and is affected by key social relationships at each developmental period. Despite high variability in how the social context is conceptualized and measured across studies, findings converge on the characteristics of social relationships that facilitate or undermine diabetes management across the life span. These characteristics are consistent with both Interpersonal Theory and Self-Determination Theory, 2 organizing frameworks that we utilize to explore social behaviors that are related to diabetes management. Involvement and support from one's social partners, particularly family members, is consistently associated with good diabetes outcomes when characterized by warmth, collaboration, and acceptance. Underinvolvement and interactions characterized by conflict and criticism are consistently associated with poor diabetes outcomes. Intrusive involvement that contains elements of social control may undermine diabetes management, particularly when it impinges on self-efficacy. Implications for future research directions and for interventions that promote the effective use of the social context to improve diabetes self-management are discussed. (PsycINFO Database Record

  7. Evaluating the life cycle environmental impact of short span bridges

    DEFF Research Database (Denmark)

    Du, Guangli; Pettersson, Lars; Karoumi, Raid

    2016-01-01

    Bridge infrastructure consumes large amount of energy and raw materials, leading to considerable environmental burdens. The traditional infrastructure construction prioritizes its technical and economic viability. In recent years, the society devotes an ever-increased attention to the environmental...... impact of the construction sector. Life cycle assessment (LCA) is a systematic method for assessing the environmental impact of products and systems, but its application in bridges is scarce. In Swede, most of the bridges are short spans and the type of concrete slab-frame bridge (CFB) accounts...... for a large share. Soil steel composite bridge (SSCB) is a functional equivalent solution for CFB. In order to mitigate the environmental burdens of short span bridges, this paper performed a comparative LCA study between these two types of bridge. The results indicate that the initial material consumption...

  8. Relation of behaviour and macrophage function to life span in a murine model of premature immunosenescence.

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    Guayerbas, Noelia; Catalán, Marina; Víctor, Víctor M; Miquel, Jaime; De la Fuente, Mónica

    2002-08-21

    According to our previous work, mice of the same strain and age show striking inter-individual differences in behaviour when exposed to a T-maze test. Further, the animals exploring the maze slowly (slow mice) or staying at the starting point (freezing behaviour), which show high levels of emotionality/anxiety in other standard behavioural tests, have a less competent immune system (earlier immunosenescence) than those which explore it quickly (fast mice). The present longitudinal study on OF-1 Swiss female mice confirms and extends the above findings. Thus, the animals showing a lower performance in the T-test (slow mice) which is accompanied by a poor neuromuscular coordination in a tightrope test, have a shorter life span than the good performers (fast mice). Moreover, the slow mice have a less competent immune system as regards the following functions of peritoneal macrophages: adherence to substrate, chemotaxis, ingestion of particles and superoxide anion production. This suggests that, at the same chronological age and as regards their immune competence, the slow mice are biologically older than the fast mice. This agrees with current ideas on the close functional relationship between the nervous and the immune system in the physiological adaptation to stress, and supports the concept that an optimum level of performance of these two systems is needed to attain a long life span.

  9. From Suns to Life: A Chronological Approach to the History of Life on Earth

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    Gargaud, Muriel; López-García, Purificación; Martin, Hervé; Montmerle, Thierry; Pascal, Robert; Reisse, Jacques

    2006-01-01

    This review emerged from several interdisciplinary meetings and schools gathering a group of astronomers, geologists, biologists, and chemists, attempting to share their specialized knowledge around a common question: how did life emerge on Earth? Their ultimate goal was to provide some kind of answer as a prerequisite to an even more demanding question: is life universal? The resulting state-of-the-art articles were written by twenty-five scientists telling a not-so linear story, but on the contrary, highlighting problems, gaps, and controversies. Needless to say, this approach yielded no definitive answers to both questions. However, by adopting a chronological approach to the question of the emergence of life on Earth, the only place where we know for sure that life exists; it was possible to break down this question into several sub-topics that can be addressed by the different disciplines. The main chapters of this review present the formation and evolution of the solar system (3); the building of a habi...

  10. Emotional Egocentricity Bias across the life-span

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    Federica eRiva

    2016-04-01

    Full Text Available In our daily lives, we often have to quickly estimate the emotions of our conspecifics in order to have successful social interactions. While this estimation process seems quite easy when we are ourselves in a neutral or equivalent emotional state, it has recently been shown that in case of incongruent emotional states between ourselves and the others, our judgments can be biased. This phenomenon, introduced to the literature with the term Emotional Egocentricity Bias (EEB, has been found to occur in young adults and, to a greater extent, in children. However, how EEB changes across the life-span from adolescence to old age has been largely unexplored. In this study, we recruited 114 female participants subdivided in four cohorts (adolescents, young adults, middle-aged adults, older adults to examine EEB age-related changes. Participants were administered with a paradigm which, by making use of visuo-tactile stimulation that elicits conflicting feelings in paired participants, allows the valid and reliable exploration of EEB. Results highlighted a U-shaped relation between age and EEB, revealing higher emotional egocentricity in adolescents and older adults compared to young and middle-aged adults. These results are in line with the neuroscientific literature which has recently shown that overcoming EEB is associated with a greater activation of a portion of the parietal lobe, namely the right Supramarginal Gyrus (rSMG. This is an area that reaches full maturation only by the end of adolescence, and displays an early decay in older age. Thus, the age-related changes of the EEB could be possibly due to the life-span development of the rSMG. This study is the first one to show the quadratic relation between age and the EEB and set a milestone for further research exploring the neural correlates of the life-span development of the EEB. Future studies are needed in order to generalize these results to the male population and to explore gender

  11. Connecting Life Span Development with the Sociology of the Life Course: A New Direction.

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    Gilleard, Chris; Higgs, Paul

    2016-04-01

    The life course has become a topic of growing interest within the social sciences. Attempts to link this sub-discipline with life span developmental psychology have been called for but with little sign of success. In this paper, we seek to address three interlinked issues concerning the potential for a more productive interchange between life course sociology and life span psychology. The first is to try to account for the failure of these two sub-disciplines to achieve any deepening engagement with each other, despite the long-expressed desirability of that goal; the second is to draw attention to the scope for enriching the sociology of the life course through Erik Erikson's model of life span development; and the last is the potential for linking Eriksonian theory with current debates within mainstream sociology about the processes involved in 'individualisation' and 'self-reflexivity' as an alternative entry point to bring together these two fields of work.

  12. Assessment of Motor Competence Across the Life Span

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    Hermundur Sigmundsson

    2016-02-01

    Full Text Available In this article, the psychometric properties of a new test battery aimed at quantifying motor competence across the life span are explored. The battery was designed to be quantitative, simple to administer, applicable for large-group testing, and reliably to monitor life span motor development. A total of 638 participants between 5 and 83 years of age completed assessment of four different motor tasks (two fine and two gross motor tasks, enabling us to investigate its feasibility, internal consistency, construct validity, and test–retest reliability. Feasibility: Overall pattern of results suggest that the test battery for motor competence presented here is applicable for the age-span studied (5-83. Important consideration in this regard is that the same tasks are applied for all ages. A u-shaped curve between age and total test score indicate the adequate sensitivity of the test battery for the age range examined. Internal consistency: All individual test item scores correlated positively with the total test score with correlations ranging from .48 to .64. Correlations between scores on individual test items were moderate to high (.31-.69. The Cronbach’s alpha value for the standardized items was .79. Construct validity: Pearson correlation coefficient between total score Test of Motor Competence (TMC and Movement Assessment Battery for Children (MABC were .47 for 7- to 8-years-old children (n = 70 and .45 for 15- to 16-years-old (n = 101. Test-retest reliability: Intraclass correlation coefficients (ICCs between test and retest scores ranged from .75 to .94, and test–retest coefficient for the total score was .87.

  13. Exercise, brain, and cognition across the life span.

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    Voss, Michelle W; Nagamatsu, Lindsay S; Liu-Ambrose, Teresa; Kramer, Arthur F

    2011-11-01

    This is a brief review of current evidence for the relationships between physical activity and exercise and the brain and cognition throughout the life span in non-pathological populations. We focus on the effects of both aerobic and resistance training and provide a brief overview of potential neurobiological mechanisms derived from non-human animal models. Whereas research has focused primarily on the benefits of aerobic exercise in youth and young adult populations, there is growing evidence that both aerobic and resistance training are important for maintaining cognitive and brain health in old age. Finally, in these contexts, we point out gaps in the literature and future directions that will help advance the field of exercise neuroscience, including more studies that explicitly examine the effect of exercise type and intensity on cognition, the brain, and clinically significant outcomes. There is also a need for human neuroimaging studies to adopt a more unified multi-modal framework and for greater interaction between human and animal models of exercise effects on brain and cognition across the life span.

  14. IQ and ability across the adult life span.

    Science.gov (United States)

    Baxendale, Sallie

    2011-07-01

    The experience of cognitive decline can be a potent source of anxiety and concern for many people. While an IQ consistent with estimated optimal levels or previously recorded scores may indicate no significant change in cognitive function, the patient may be accurately reporting a normal age-related deterioration in actual ability. The aim of this article is to chart the age-related changes in intellectual abilities evident on the Wechsler Adult Intelligence Scales-Fourth Edition (WAIS-IV). The norms from the WAIS-IV manual were examined to plot the age-related changes in Full-Scale IQ (FSIQ) and composite scores across the adult life span, while holding actual ability level constant across the age groups. Here we present a graphical representation of the normal cognitive developments and declines in FSIQ, Verbal Comprehension, Perceptual Reasoning, Working Memory, and Processing Speed across the adult life span. This graphical representation provides a rational basis for the identification of atypical profiles/complaints of cognitive deterioration that may require further specialist neuropsychological evaluation. These graphs can be used to provide reassurance for healthy adults with concerns of cognitive decline and as an educative tool for their referring agencies.

  15. Emotional Egocentricity Bias Across the Life-Span.

    Science.gov (United States)

    Riva, Federica; Triscoli, Chantal; Lamm, Claus; Carnaghi, Andrea; Silani, Giorgia

    2016-01-01

    In our daily lives, we often have to quickly estimate the emotions of our conspecifics in order to have successful social interactions. While this estimation process seems quite easy when we are ourselves in a neutral or equivalent emotional state, it has recently been shown that in case of incongruent emotional states between ourselves and the others, our judgments can be biased. This phenomenon, introduced to the literature with the term Emotional Egocentricity Bias (EEB), has been found to occur in young adults and, to a greater extent, in children. However, how the EEB changes across the life-span from adolescence to old age has been largely unexplored. In this study, we recruited 114 female participants subdivided in four cohorts (adolescents, young adults, middle-aged adults, older adults) to examine EEB age-related changes. Participants were administered with a recently developed paradigm which, by making use of visuo-tactile stimulation that elicits conflicting feelings in paired participants, allows the valid and reliable exploration of the EEB. Results highlighted a U-shape relation between age and EEB, revealing enhanced emotional egocentricity in adolescents and older adults compared to young and middle-aged adults. These results are in line with the neuroscientific literature which has recently shown that overcoming the EEB is associated with a greater activation of a portion of the parietal lobe, namely the right Supramarginal Gyrus (rSMG). This is an area that reaches full maturation by the end of adolescence and goes through an early decay. Thus, the age-related changes of the EEB could be possibly due to the life-span development of the rSMG. This study is the first one to show the quadratic relation between age and the EEB and set a milestone for further research exploring the neural correlates of the life-span development of the EEB. Future studies are needed in order to generalize these results to the male population and to explore gender

  16. Explanations of a magic trick across the life span

    Directory of Open Access Journals (Sweden)

    Jay A Olson

    2015-03-01

    Full Text Available Studying how children and adults explain magic tricks can reveal developmental differences in cognition. We showed 167 children (aged 4 to 13 years a video of a magician making a pen vanish and asked them to explain the trick. Although most claimed to know 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.

  17. Dendrin ablation prolongs life span by delaying kidney failure.

    Science.gov (United States)

    Weins, Astrid; Wong, Jenny S; Basgen, John M; Gupta, Ritu; Daehn, Ilse; Casagrande, Lisette; Lessman, David; Schwartzman, Monica; Meliambro, Kristin; Patrakka, Jaakko; Shaw, Andrey; Tryggvason, Karl; He, John Cijiang; Nicholas, Susanne B; Mundel, Peter; Campbell, Kirk N

    2015-08-01

    Podocyte loss is central to the progression of proteinuric kidney diseases leading to end-stage kidney disease (ESKD), requiring renal replacement therapy, such as dialysis. Despite modern tools and techniques, the 5-year mortality of some patients requiring dialysis remains at about 70% to 80%. Thus, there is a great unmet need for podocyte-specific treatments aimed at preventing podocyte loss and the ensuing development of ESKD. Here, we show that ablation of the podocyte death-promoting protein dendrin delays the onset of ESKD, thereby expanding the life span of mice lacking the adapter protein CD2AP. Ablation of dendrin delays onset and severity of proteinuria and podocyte loss. In addition, dendrin ablation ameliorates mesangial volume expansion and up-regulation of mesangial fibronectin expression, which is mediated by a podocyte-secreted factor. In conclusion, onset of ESKD and death can be markedly delayed by blocking the function of dendrin.

  18. The Life Span Model of Suicide and Its Neurobiological Foundation

    Science.gov (United States)

    Ludwig, Birgit; Roy, Bhaskar; Wang, Qingzhong; Birur, Badari; Dwivedi, Yogesh

    2017-01-01

    The very incomprehensibility of the suicidal act has been occupying the minds of researchers and health professionals for a long time. Several theories of suicide have been proposed since the beginning of the past century, and a myriad of neurobiological studies have been conducted over the past two decades in order to elucidate its pathophysiology. Both neurobiology and psychological theories tend to work in parallel lines that need behavioral and empirical data respectively, to confirm their hypotheses. In this review, we are proposing a “Life Span Model of Suicide” with an attempt to integrate the “Stress-Diathesis Model” and the “Interpersonal Model of Suicide” into a neurobiological narrative and support it by providing a thorough compilation of related genetic, epigenetic, and gene expression findings. This proposed model comprises three layers, forming the capability of suicide: genetic factors as the predisposing Diathesis on one side and Stress, characterized by epigenetic marks on the other side, and in between gene expression and gene function which are thought to be influenced by Diathesis and Stress components. The empirical evidence of this model is yet to be confirmed and further research, specifically epigenetic studies in particular, are needed to support the presence of a life-long, evolving capability of suicide and identify its neurobiological correlates. PMID:28261051

  19. Oxygen analyzers: failure rates and life spans of galvanic cells.

    Science.gov (United States)

    Meyer, R M

    1990-07-01

    Competing technologies exist for measuring oxygen concentrations in breathing circuits. Over a 4-year period, two types of oxygen analyzers were studied prospectively in routine clinical use to determine the incidence and nature of malfunctions. Newer AC-powered galvanic analyzers (North American Dräger O2med) were compared with older, battery-powered polarographic analyzers (Ohmeda 201) by recording all failures and necessary repairs. The AC-powered galvanic analyzer had a significantly lower incidence of failures (0.12 +/- 0.04 failures per machine-month) than the battery-powered polarographic analyzer (4.0 +/- 0.3 failures per machine-month). Disposable capsules containing the active galvanic cells lasted 12 +/- 7 months. Although the galvanic analyzers tended to remain out of service longer, awaiting the arrival of costly parts, the polarographic analyzers were more expensive to keep operating when calculations included the cost of time spent on repairs. Stocking galvanic capsules would have decreased the amount of time the galvanic analyzers were out of service, while increasing costs. In conclusion, galvanic oxygen analyzers appear capable of delivering more reliable service at a lower overall cost. By keeping the galvanic capsules exposed to room air during periods of storage, it should be possible to prolong their life span, further decreasing the cost of using them. In addition, recognizing the aberrations in their performance that warn of the exhaustion of the galvanic cells should permit timely recording and minimize downtime.

  20. Colour constancy across the life span: evidence for compensatory mechanisms.

    Science.gov (United States)

    Wuerger, Sophie

    2013-01-01

    It is well known that the peripheral visual system declines with age: the yellowing of the lens causes a selective reduction of short-wavelength light and sensitivity losses occur in the cone receptor mechanisms. At the same time, our subjective experience of colour does not change with age. The main purpose of this large-scale study (n = 185) covering a wide age range of colour-normal observers (18-75 years of age) was to assess the extent to which the human visual system is able to compensate for the changes in the optical media and at which level of processing this compensation is likely to occur. We report two main results: (1) Supra-threshold parafoveal colour perception remains largely unaffected by the age-related changes in the optical media (yellowing of the lens) whereas our ability to discriminate between small colour differences is compromised with an increase in age. (2) Significant changes in colour appearance are only found for unique green settings under daylight viewing condition which is consistent with the idea that the yellow-blue mechanism is most affected by an increase in age due to selective attenuation of short-wavelength light. The data on the invariance of hue perception, in conjunction with the age-related decline in chromatic sensitivity, provides evidence for compensatory mechanisms that enable colour-normal human observers a large degree of colour constancy across the life span. These compensatory mechanisms are likely to originate at cortical sites.

  1. From past to future: Temporal self-continuity across the life span.

    Science.gov (United States)

    Rutt, Joshua L; Löckenhoff, Corinna E

    2016-09-01

    Although perceived continuity with one's future self has attracted increasing research interest, age differences in this phenomenon remain poorly understood. The present study is the first to simultaneously examine past and future self-continuity across multiple temporal distances using both explicit and implicit measures and controlling for a range of theoretically implicated covariates in an adult life span sample (N = 91, aged 18-92, M = 50.15, SD = 19.20, 56% female). Perceived similarity to one's self across 6 past and 6 future time points (1 month to 10 years) was assessed with an explicit self-report measure and an implicit me/not me trait rating task. In multilevel analyses, age was significantly associated with greater implicit and explicit self-continuity, especially for more distant intervals. Further, reaction times (RTs) in the implicit task remained stable with temporal distance for older adults but decreased with temporal distance for younger adults, especially for future ratings. This points toward age differences in the underlying mechanisms of self-continuity. Multilevel models examined the role of various covariates including personality, cognition, future horizons, and subjective health and found that none of them could fully account for the observed age effects. Taken together, our findings suggest that chronological age is associated with greater self-continuity although specific mechanisms and correlates may vary by age. (PsycINFO Database Record

  2. Angiotensin Converting Enzyme (ACE) Inhibitor Extends Caenorhabditis elegans Life Span.

    Science.gov (United States)

    Kumar, Sandeep; Dietrich, Nicholas; Kornfeld, Kerry

    2016-02-01

    Animal aging is characterized by progressive, degenerative changes in many organ systems. Because age-related degeneration is a major contributor to disability and death in humans, treatments that delay age-related degeneration are desirable. However, no drugs that delay normal human aging are currently available. To identify drugs that delay age-related degeneration, we used the powerful Caenorhabditis elegans model system to screen for FDA-approved drugs that can extend the adult lifespan of worms. Here we show that captopril extended mean lifespan. Captopril is an angiotensin-converting enzyme (ACE) inhibitor used to treat high blood pressure in humans. To explore the mechanism of captopril, we analyzed the acn-1 gene that encodes the C. elegans homolog of ACE. Reducing the activity of acn-1 extended the mean life span. Furthermore, reducing the activity of acn-1 delayed age-related degenerative changes and increased stress resistance, indicating that acn-1 influences aging. Captopril could not further extend the lifespan of animals with reduced acn-1, suggesting they function in the same pathway; we propose that captopril inhibits acn-1 to extend lifespan. To define the relationship with previously characterized longevity pathways, we analyzed mutant animals. The lifespan extension caused by reducing the activity of acn-1 was additive with caloric restriction and mitochondrial insufficiency, and did not require sir-2.1, hsf-1 or rict-1, suggesting that acn-1 functions by a distinct mechanism. The interactions with the insulin/IGF-1 pathway were complex, since the lifespan extensions caused by captopril and reducing acn-1 activity were additive with daf-2 and age-1 but required daf-16. Captopril treatment and reducing acn-1 activity caused similar effects in a wide range of genetic backgrounds, consistent with the model that they act by the same mechanism. These results identify a new drug and a new gene that can extend the lifespan of worms and suggest new

  3. Life Span Extension and Neuronal Cell Protection by Drosophila Nicotinamidase*S⃞

    OpenAIRE

    Balan, Vitaly; Gregory S Miller; Kaplun, Ludmila; Balan, Karina; Chong, Zhao-Zhong; Li, Faqi; Kaplun, Alexander; Mark F A VanBerkum; Arking, Robert; Freeman, D. Carl; Maiese, Kenneth; Tzivion, Guri

    2008-01-01

    The life span of model organisms can be modulated by environmental conditions that influence cellular metabolism, oxidation, or DNA integrity. The yeast nicotinamidase gene pnc1 was identified as a key transcriptional target and mediator of calorie restriction and stress-induced life span extension. PNC1 is thought to exert its effect on yeast life span by modulating cellular nicotinamide and NAD levels, resulting in increased activity of Sir2 family class III histone ...

  4. The Rate of Source Memory Decline across the Adult Life Span

    Science.gov (United States)

    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

    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…

  5. Blade life span, structural investment, and nutrient allocation in giant kelp.

    Science.gov (United States)

    Rodriguez, Gabriel E; Reed, Daniel C; Holbrook, Sally J

    2016-10-01

    The turnover of plant biomass largely determines the amount of energy flowing through an ecosystem and understanding the processes that regulate turnover has been of interest to ecologists for decades. Leaf life span theory has proven useful in explaining patterns of leaf turnover in relation to resource availability, but the predictions of this theory have not been tested for macroalgae. We measured blade life span, size, thickness, nitrogen content, pigment content, and maximum photosynthetic rate (P max) in the giant kelp (Macrocystis pyrifera) along a strong resource (light) gradient to test whether the predictions of leaf life span theory applied to this alga. We found that shorter blade life spans and larger blade areas were associated with increased light availability. In addition, nitrogen and P max decreased with blade age, and their decrease was greater in shorter lived blades. These observations are generally consistent with patterns observed for higher plants and the prevailing theory of leaf life span. By contrast, variation observed in pigments of giant kelp was inconsistent with that predicted by leaf life span theory, as blades growing in the most heavily shaded portion of the forest had the lowest chlorophyll content. This result may reflect the dual role of macroalgal blades in carbon fixation and nutrient absorption and the ability of giant kelp to modify blade physiology to optimize the acquisition of light and nutrients. Thus, the marine environment may place demands on resource acquisition and allocation that have not been previously considered with respect to leaf life span optimization.

  6. Ageless and Timeless: Perspectives on Giftedness across the Life Span

    Science.gov (United States)

    Fiedler, Ellen D.

    2016-01-01

    Annemarie Roeper's timeless perspectives were demonstrated throughout her long and productive life. Her prolific writings and speeches continue to influence our understanding of giftedness at all ages and stages of life, and the time I spent with her had a profound and meaningful effect on my work. Annemarie incorporated her inner view of…

  7. Life-span plasticity of the brain and cognition: from questions to evidence and back.

    Science.gov (United States)

    Raz, Naftali; Lindenberger, Ulman

    2013-11-01

    Experience-related changes induced by modification of environment, physical exercise, or cognitive training affect brain structure and function. Research on brain plasticity and its relationship to experiential changes gathers momentum and attracts significant public interest. This collection of papers is based on presentation at the First International Conference on Life-Span Plasticity of Brain and Behavior: A Cognitive Neuroscience Perspective that took place in Detroit, MI, on October 12-14, 2011. The conference honored Margret M. and Paul B. Baltes, the pioneers of life-span developmental psychology who initiated some of the first studies on experience- and training-related changes in cognition across the life span.

  8. Mathematical Basis of Idea That Harmonious Marriage Can Lengthen Life-span

    Institute of Scientific and Technical Information of China (English)

    Zhi-qiang Zhang

    2009-01-01

    It is a very important issue for us to explore the effects of the marriage to life. In recent years, many scholars have proved that the marriage can lengthen life-span from different angles. With the development of theory of dependence random variables, we discuss the effects of the marriage to life and provide a mathematical basis of the idea that the harmonious marriage can lengthen life-span in this paper. Meanwhile, we analyze the impact of the marriage on life on the basis of the net single premium.

  9. Life span of common marmoset (Callithrix jacchus) at CLEA Japan breeding colony.

    Science.gov (United States)

    Nishijima, Kazutoshi; Saitoh, Ryoichi; Tanaka, Shin; Ohsato-Suzuki, Motoko; Ohno, Tamio; Kitajima, Shuji

    2012-08-01

    The life span and survival parameters of the common marmoset (Callithrix jacchus) in a breeding colony at CLEA Japan, Inc. were investigated. The average life span of male marmosets was 148.5 ± 6.1 (mean ± SE) months of age (M), which was significantly longer (P marmosets show a slight decline in survival during the first 7-9 years and then a dramatic decrease and another slight decline after 14-16 year of age in survival, i.e., a lifespan curve similar to what is observed in colonies of aging rodents and humans. The sex-associated difference in life span was caused by reproductive burden on the females. The present study reported a longer than expected life span of the marmoset, and a long-lived animal can be a powerful model for senescence and longevity sciences.

  10. Is altered expression of hepatic insulin-related genes in growth hormone receptor knockout mice due to GH resistance or a difference in biological life spans?

    Science.gov (United States)

    Panici, Jacob A; Wang, Feiya; Bonkowski, Michael S; Spong, Adam; Bartke, Andrzej; Pawlikowska, Ludmila; Kwok, Pui-Yan; Masternak, Michal M

    2009-11-01

    Growth hormone receptor knockout (GHRKO) mice live about 40%-55% longer than their normal (N) littermates. Previous studies of 21-month-old GHRKO and N mice showed major alterations of the hepatic expression of genes involved in insulin signaling. Differences detected at this age may have been caused by the knockout of the growth hormone receptor (GHR) or by differences in biological age between GHRKO and N mice. To address this question, we compared GHRKO and N mice at ages corresponding to the same percentage of median life span to see if the differences of gene expression persisted. Comparison of GHRKO and N mice at approximately 50% of biological life span showed significant differences in hepatic expression of all 14 analyzed genes. We conclude that these changes are due to disruption of GHR gene and the consequent suppression of growth hormone signaling rather than to differences in "biological age" between mutant and normal animals sampled at the same chronological age.

  11. A Study on Engine Life Span Based on Engine Assembly Quality Analysis

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    In this paper, the main effective factors of engine assembly quality have been analyzed in detail. It provided a mathematical model of engine life span based on the laws of the changirng of friction pairs gap and running-in analysis. On the basis of a EQ6100 engine test, the applied spectral analysis technique, it gained efficient technique measures to enhance the engine 's life span, and provided a proposal value and an allowed value of integrated position precision error.

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

    Science.gov (United States)

    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

    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.

  13. If started early in life, metformin treatment increases life span and postpones tumors in female SHR mice

    Science.gov (United States)

    Anisimov, Vladimir N.; Berstein, Lev M.; Popovich, Irina G.; Zabezhinski, Mark A.; Egormin, Peter A.; Piskunova, Tatiana S.; Semenchenko, Anna V.; Tyndyk, Margarita L.; Yurova, Maria N.; Kovalenko, Irina G.; Poroshina, Tatiana E.

    2011-01-01

    Hyperglycemia and hyperinsulinemia accelerate both aging and cancer. Antidiabetic biguanides such as metformin decrease glucose, insulin and IGF-1 level. Metformin increases lifespan and prevents cancer in mice, although its effects vary, depending on mice strain and gender. Here we showed that chronic treatment of female outbred SHR mice with metformin started at the age of 3, 9 or 15 months decreased body temperature and postponed age-related switch-off of estrous function. Surprisingly, metformin did not affect levels of serum cholesterol, triglycerides, glucose and insulin. Treatment with metformin started at the age of 3 months increased mean life span by 14% and maximum life span by 1 month. The treatment started at the age of 9 months insignificantly increased mean life span by only 6%, whereas the treatment started at the age of 15 months failed to increase life span. The mean life span of tumor-free mice was increased by 21% in ‘the youngest group’, by 7% in ‘middle-aged group’ and in contrast was reduced by 13% in ‘the oldest group’. When started at the age of 3 and 9 months, metformin delayed the first tumor detection by 22% and 25%, correspondingly. Thus, in female SHR mice, metformin increased life span and postponed tumors when started at the young and middle but not at the old age. In contrast, metformin improves reproductive function when started at any age. PMID:21386129

  14. Life-span adjustment of children to their parents' divorce.

    Science.gov (United States)

    Amato, P R

    1994-01-01

    Children who experience parental divorce, compared with children in intact two-parent families, exhibit more conduct problems, more symptoms of psychological maladjustment, lower academic achievement, more social difficulties, and poorer self-concepts. Similarly, adults who experienced parental divorce as children, compared with adults raised in continuously intact two-parent families, score lower on a variety of indicators of psychological, interpersonal, and socioeconomic well-being. However, the overall group differences between offspring from divorced and intact families are small, with considerable diversity existing in children's reactions to divorce. Children's adjustment to divorce depends on several factors, including the amount and quality of contact with noncustodial parents, the custodial parents' psychological adjustment and parenting skills, the level of interparental conflict that precedes and follows divorce, the degree of economic hardship to which children are exposed, and the number of stressful life events that accompany and follow divorce. These factors can be used as guides to assess the probable impact of various legal and therapeutic interventions to improve the well-being of children of divorce.

  15. Increased Life Span due to Calorie Restriction in Respiratory-Deficient Yeast.

    Directory of Open Access Journals (Sweden)

    2005-11-01

    Full Text Available A model for replicative life span extension by calorie restriction (CR in yeast has been proposed whereby reduced glucose in the growth medium leads to activation of the NAD-dependent histone deacetylase Sir2. One mechanism proposed for this putative activation of Sir2 is that CR enhances the rate of respiration, in turn leading to altered levels of NAD or NADH, and ultimately resulting in enhanced Sir2 activity. An alternative mechanism has been proposed in which CR decreases levels of the Sir2 inhibitor nicotinamide through increased expression of the gene coding for nicotinamidase, PNC1. We have previously reported that life span extension by CR is not dependent on Sir2 in the long-lived BY4742 strain background. Here we have determined the requirement for respiration and the effect of nicotinamide levels on life span extension by CR. We find that CR confers robust life span extension in respiratory-deficient cells independent of strain background, and moreover, suppresses the premature mortality associated with loss of mitochondrial DNA in the short-lived PSY316 strain. Addition of nicotinamide to the medium dramatically shortens the life span of wild type cells, due to inhibition of Sir2. However, even in cells lacking both Sir2 and the replication fork block protein Fob1, nicotinamide partially prevents life span extension by CR. These findings (1 demonstrate that respiration is not required for the longevity benefits of CR in yeast, (2 show that nicotinamide inhibits life span extension by CR through a Sir2-independent mechanism, and (3 suggest that CR acts through a conserved, Sir2-independent mechanism in both PSY316 and BY4742.

  16. Life Span and Motility Effects of Ethanolic Extracts from Sophora moorcroftiana Seeds on Caenorhabditis elegans

    Science.gov (United States)

    Li, Xin; Han, Junxian; Zhu, Rongyan; Cui, Rongrong; Ma, Xingming; Dong, Kaizhong

    2016-01-01

    Background: Sophora moorcroftiana is an endemic shrub species with a great value in folk medicine in Tibet, China. In this study, relatively little is known about whether S. moorcroftiana is beneficial in animals' nervous system and life span or not. Materials and Methods: To address this question, under survival normal temperature (25°C), S. moorcroftiana seeds were extracted with 95% ethanol, and Caenorhabditis elegans were exposed to three different extract concentrations (100 mg/L, 200 mg/L, and 400 mg/mL) from S. moorcroftiana seeds. Results: The 95% ethanolic extracts from S. moorcroftiana seeds could increase life span and slow aging-related increase in C. elegans and could not obviously influence the motility of C. elegans. Conclusion: Given these results by our experiment for life span and motility with 95% ethanolic extracts from S. moorcroftiana seeds in C. elegans, the question whether S. moorcroftiana acts as an anti-aging substance in vivo arises. SUMMARY The 95% ethanolic extracts from S. moorcroftiana seeds have no effect on the life span in C. elegans when extract concentrations from S. moorcroftiana seeds <400 mg/LThe 400 mg/L 95% ethanolic extracts from S. moorcroftiana seeds could increase life span in C. elegansThe 95% ethanolic extracts from S. moorcroftiana seeds could not obviously influence the motility in C. elegans. Abbreviation used: S. moorcroftiana: Sophora moorcroftiana; C. elegan: Caenorhabditis elegan; E. coli OP50: Escherichia coli OP50; DMSO: Dimethyl sulfoxide. PMID:27279712

  17. [The traits theory in longitudinal life span research. Partial report of a workshop].

    Science.gov (United States)

    Munnichs, J M

    1982-12-01

    During the international Workshop on 'Life Span and Change in a Gerontological Perspective' (9-12 July, 1981) at the University of Nijmegen, the Netherlands, research data from the Oakland Growth Study and the Guidance Study have been discussed. The second major contribution came from the longitudinal studies at the Bonn University. These groups of researchers cover different periods in the life span, but both contribute to prediction and understanding of periods not under investigation. Each of these longitudinal studies can contribute to the total understanding of the psychology of the life span. In this contribution we describe the trait-centered approach. The older research is mostly done with this theoretical approach in mind. We summarize the Californian studies and the Manhattan study on mental health. We close with some general critical remarks and we try to define the limitations of the trait-theoretical approach.

  18. Tequila Regulates Insulin-Like Signaling and Extends Life Span in Drosophila melanogaster.

    Science.gov (United States)

    Huang, Cheng-Wen; Wang, Horng-Dar; Bai, Hua; Wu, Ming-Shiang; Yen, Jui-Hung; Tatar, Marc; Fu, Tsai-Feng; Wang, Pei-Yu

    2015-12-01

    The aging process is a universal phenomenon shared by all living organisms. The identification of longevity genes is important in that the study of these genes is likely to yield significant insights into human senescence. In this study, we have identified Tequila as a novel candidate gene involved in the regulation of longevity in Drosophila melanogaster. We have found that a hypomorphic mutation of Tequila (Teq(f01792)), as well as cell-specific downregulation of Tequila in insulin-producing neurons of the fly, significantly extends life span. Tequila deficiency-induced life-span extension is likely to be associated with reduced insulin-like signaling, because Tequila mutant flies display several common phenotypes of insulin dysregulation, including reduced circulating Drosophila insulin-like peptide 2 (Dilp2), reduced Akt phosphorylation, reduced body size, and altered glucose homeostasis. These observations suggest that Tequila may confer life-span extension by acting as a modulator of Drosophila insulin-like signaling.

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

    Science.gov (United States)

    Takahashi, Keiko

    2005-01-01

    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…

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

    Science.gov (United States)

    Dykas, Matthew J.; Cassidy, Jude

    2011-01-01

    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…

  1. A bodyweight-dependent allometric exponent for scaling clearance across the human life-span

    NARCIS (Netherlands)

    C. Wang (Chenguang); M.Y. Peeters (Mariska); K. Allegaert (Karel); H.J. Blussé van Oud-Alblas (Heleen); E.H.J. Krekels (Elke); D. Tibboel (Dick); M. Danhof (Meindert); C.A.J. Knibbe (Catherijne)

    2012-01-01

    textabstractPurpose: To explore different allometric equations for scaling clearance across the human life-span using propofol as a model drug. Methods: Data from seven previously published propofol studies ((pre)term neonates, infants, toddlers, children, adolescents and adults) were analysed using

  2. Investigating the life-span of cork products through a longitudinal approach with users- Interim results

    NARCIS (Netherlands)

    Da Silva Pereira, A.C.; Brezet, J.C.; Pereira, H.; Vogtlander, J.G.

    2012-01-01

    Products with long life-spans are generally preferred form an environmental perspective. This paper addresses the longevity of cork products, and the respective influencing aspects. This is accomplished through a longitudinal study where several cork products are used, and at different moments in ti

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

    Science.gov (United States)

    Papalia, Diane E.

    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…

  4. Female Early Adolescent Sex Role Attitude and Behavior Development: A Life Span, Ecosystem Approach.

    Science.gov (United States)

    Nelson, Christine Seipke; Keith, Joanne

    Theory and research related to early adolescent sex role development needs to be addressed from both a life-span and an ecological perspective. A study was conducted to examine the development of female early adolescent sex role attitudes and behaviors in an ecological context as defined by Urie Bronfenbrenner. Data were the results of a…

  5. Target of rapamycin signaling regulates metabolism, growth, and life span in Arabidopsis.

    Science.gov (United States)

    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

    2012-12-01

    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.

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

    Science.gov (United States)

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

    2010-01-01

    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…

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

    Science.gov (United States)

    Dodd, Helen F.; Porter, Melanie A.

    2009-01-01

    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…

  8. [THE ANALYSIS OF LIFE SPAN AND MORTALITY OF PATIENTS WITH SPINOCEREBELLAR ATAXIA TYPE I].

    Science.gov (United States)

    Tikhonov, D G; Goldfarb, L G; Neustroeva, T S; Yakovleva, N V; Timofeev, L F; Luckan, I P; Platonov, F A

    2015-01-01

    The article presents results of investigation of certain unclear aspects of mortality of patients with spinocerebellar ataxia type I including patients with the same number of CAG-repetitions. The analysis of mortality of patients observed from 1993 to nowadays was implemented. Sampling included 112 patients during that period 53 patients died. The comparative analysis was implemented concerning received data and results of analysis of mortality of patients died prior to 1980. According received data, average value of CAG-repetitions of normal allele was equal to 30.2, and ofpathologic allele--48.7. The average life span made up to 52.8 years, average age of disease onset--38 years and natural duration of disease--14.8 years. The analysis of life span of patients with equal length of repetitions demonstrated that range of life span of patients makes up to from 8 to 23 years. It is established that life of patients becomes shorter because of accidents, cancer and concomitant diseases of cardiovascular system. The presence of such concomitant disease as tuberculosis of lungs results in no shortening of life of patients. The comparative analysis of mortality during the period over 34 years demonstrated that age of disease onset turned out to be more conservative and stable indicator of morbidity. Despite of lacking of effective methods of treatment of disease, the natural duration of disease increased statistically reliable up to 1.8 times during period of observation. The analysis of life span ofpatients with spinocerebellar ataxia type I demonstrated that their life span except length of CAG-expansion depends on a number of factors accelerating and retarding development of disease. At that, life span of patients with the same number of CAG-repetitions can significantly differ The malignant neoplasms, diseases of cardiovascular system and external causes are to be referred to factors accelerating and retarding development of main disease. The addition oftuberculosis

  9. ETS-4 is a transcriptional regulator of life span in Caenorhabditis elegans.

    Directory of Open Access Journals (Sweden)

    Bargavi Thyagarajan

    2010-09-01

    Full Text Available Aging is a complex phenotype responsive to a plethora of environmental inputs; yet only a limited number of transcriptional regulators are known to influence life span. How the downstream expression programs mediated by these factors (or others are coordinated into common or distinct set of aging effectors is an addressable question in model organisms, such as C. elegans. Here, we establish the transcription factor ETS-4, an ortholog of vertebrate SPDEF, as a longevity determinant. Adult worms with ets-4 mutations had a significant extension of mean life span. Restoring ETS-4 activity in the intestine, but not neurons, of ets-4 mutant worms rescued life span to wild-type levels. Using RNAi, we demonstrated that ets-4 is required post-developmentally to regulate adult life span; thus uncoupling the role of ETS-4 in aging from potential functions in worm intestinal development. Seventy ETS-4-regulated genes, identified by gene expression profiling of two distinct ets-4 alleles and analyzed by bioinformatics, were enriched for known longevity effectors that function in lipid transport, lipid metabolism, and innate immunity. Putative target genes were enriched for ones that change expression during normal aging, the majority of which are controlled by the GATA factors. Also, some ETS-4-regulated genes function downstream of the FOXO factor, DAF-16 and the insulin/IGF-1 signaling pathway. However, epistasis and phenotypic analyses indicate that ets-4 functioned in parallel to the insulin/IGF-1 receptor, daf-2 and akt-1/2 kinases. Furthermore, ets-4 required daf-16 to modulate aging, suggesting overlap in function at the level of common targets that affect life span. In conclusion, ETS-4 is a new transcriptional regulator of aging, which shares transcriptional targets with GATA and FOXO factors, suggesting that overlapping pathways direct common sets of lifespan-related genes.

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

    Science.gov (United States)

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

    2013-03-01

    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.

  11. Non-linear impact of glutathione depletion on C. elegans life span and stress resistance

    Directory of Open Access Journals (Sweden)

    Nadine Urban

    2017-04-01

    Full Text Available The redox environment in cells and organisms is set by low-molecular mass and protein-bound thiols, with glutathione (GSH representing a major intracellular redox buffer. Subtle thiol oxidation elicits signal transduction processes and adaptive responses to cope with stressors, whereas highly oxidizing conditions may provoke cell death. We here tested how thiol depletion affects life span, stress resistance and stress signaling in the model organism Caenorhabditis elegans. Diethyl maleate (DEM, an α,β-unsaturated carbonyl compound that conjugates to GSH and other thiols, decreased C. elegans life span at a concentration of 1 mM. In contrast, low and moderate doses of DEM (10–100 µM increased mean and maximum life span and improved resistance against oxidative stress. DEM-induced life span extension was not detectable in worms deficient in either the FoxO orthologue, DAF-16, or the Nrf2 orthologue, SKN-1, pointing to a collaborative role of the two transcription factors in life span extension induced by thiol depletion. Cytoprotective target genes of DAF-16 and SKN-1 were upregulated after at least 3 days of exposure to 100 µM DEM, but not 1 mM DEM, whereas only 1 mM DEM caused upregulation of egl-1, a gene controlled by a p53-orthologue, CEP-1. In order to test whether depletion of GSH may elicit effects similar to DEM, we suppressed GSH biosynthesis in worms by attenuating γ-glutamylcysteine synthetase (gcs-1 expression through RNAi. The decline in GSH levels elicited by gcs-1 knockdown starting at young adult stage did not impair viability, but increased both stress resistance and life expectancy of the worms. In contrast, gcs-1 knockdown commencing right after hatching impaired nematode stress resistance and rendered young adult worms prone to vulval ruptures during egg-laying. Thus, modest decrease in GSH levels in young adult worms may promote stress resistance and life span, whereas depletion of GSH is detrimental to freshly

  12. C. elegans VANG-1 modulates life span via insulin/IGF-1-like signaling.

    Directory of Open Access Journals (Sweden)

    Sebastian J Honnen

    Full Text Available The planar cell polarity (PCP pathway is highly conserved from Drosophila to humans and a PCP-like pathway has recently been described in the nematode Caenorhabditis elegans. The developmental function of this pathway is to coordinate the orientation of cells or structures within the plane of an epithelium or to organize cell-cell intercalation required for correct morphogenesis. Here, we describe a novel role of VANG-1, the only C. elegans ortholog of the conserved PCP component Strabismus/Van Gogh. We show that two alleles of vang-1 and depletion of the protein by RNAi cause an increase of mean life span up to 40%. Consistent with the longevity phenotype vang-1 animals also show enhanced resistance to thermal- and oxidative stress and decreased lipofuscin accumulation. In addition, vang-1 mutants show defects like reduced brood size, decreased ovulation rate and prolonged reproductive span, which are also related to gerontogenes. The germline, but not the intestine or neurons, seems to be the primary site of vang-1 function. Life span extension in vang-1 mutants depends on the insulin/IGF-1-like receptor DAF-2 and DAF-16/FoxO transcription factor. RNAi against the phase II detoxification transcription factor SKN-1/Nrf2 also reduced vang-1 life span that might be explained by gradual inhibition of insulin/IGF-1-like signaling in vang-1. This is the first time that a key player of the PCP pathway is shown to be involved in the insulin/IGF-1-like signaling dependent modulation of life span in C. elegans.

  13. 20S proteasome activation promotes life span extension and resistance to proteotoxicity in Caenorhabditis elegans.

    Science.gov (United States)

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

    2015-02-01

    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.

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

    Science.gov (United States)

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

    2013-04-01

    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 μmol 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

  15. Gender differences in metformin effect on aging, life span and spontaneous tumorigenesis in 129/Sv mice

    Science.gov (United States)

    Anisimov, Vladimir N.; Piskunova, Tatiana S.; Popovich, Irina G.; Zabezhinski, Mark A.; Tyndyk, Margarita L.; Egormin, Peter A.; Yurova, Maria N.; Rosenfeld, Svetlana V.; Semenchenko, Anna V.; Kovalenko, Irina G.; Poroshina, Tatiana E.; Berstein, Lev M.

    2010-01-01

    Studies in mammals have led to the suggestion that hyperglycemia and hyperinsulinemia are important factors both in aging and in the development of cancer. It is possible that the life-prolonging effects of calorie restriction are due to decreasing IGF-1 levels. A search of pharmacological modulators of insulin/IGF-1 signaling pathway (which mimetic effects of life span extending mutations or calorie restriction) could be a perspective direction in regulation of longevity. Antidiabetic biguanides are most promising among them. The chronic treatment of inbred 129/Sv mice with metformin (100 mg/kg in drinking water) slightly modified the food consumption but failed to influence the dynamics of body weight, decreased by 13.4% the mean life span of male mice and slightly increased the mean life span of female mice (by 4.4%). The treatment with metformin failed influence spontaneous tumor incidence in male 129/Sv mice, decreased by 3.5 times the incidence of malignant neoplasms in female mice while somewhat stimulated formation of benign vascular tumors in the latter. PMID:21164223

  16. Metal-based superoxide dismutase and catalase mimics reduce oxidative stress biomarkers and extend life span of Saccharomyces cerevisiae.

    Science.gov (United States)

    Ribeiro, Thales de P; Fonseca, Fernanda L; de Carvalho, Mariana D C; Godinho, Rodrigo M da C; de Almeida, Fernando Pereira; Saint'Pierre, Tatiana D; Rey, Nicolás A; Fernandes, Christiane; Horn, Adolfo; Pereira, Marcos D

    2017-01-15

    Aging is a natural process characterized by several biological changes. In this context, oxidative stress appears as a key factor that leads cells and organisms to severe dysfunctions and diseases. To cope with reactive oxygen species and oxidative-related damage, there has been increased use of superoxide dismutase (SOD)/catalase (CAT) biomimetic compounds. Recently, we have shown that three metal-based compounds {[Fe(HPClNOL)Cl2]NO3, [Cu(HPClNOL)(CH3CN)](ClO4)2 and Mn(HPClNOL)(Cl)2}, harboring in vitro SOD and/or CAT activities, were critical for protection of yeast cells against oxidative stress. In this work, treating Saccharomyces cerevisiae with these SOD/CAT mimics (25.0 µM/1 h), we highlight the pivotal role of these compounds to extend the life span of yeast during chronological aging. Evaluating lipid and protein oxidation of aged cells, it becomes evident that these mimics extend the life expectancy of yeast mainly due to the reduction in oxidative stress biomarkers. In addition, the treatment of yeast cells with these mimics regulated the amounts of lipid droplet occurrence, consistent with the requirement and protection of lipids for cell integrity during aging. Concerning SOD/CAT mimics uptake, using inductively coupled plasma mass spectrometry, we add new evidence that these complexes, besides being bioabsorbed by S. cerevisiae cells, can also affect metal homeostasis. Finally, our work presents a new application for these SOD/CAT mimics, which demonstrate a great potential to be employed as antiaging agents. Taken together, these promising results prompt future studies concerning the relevance of administration of these molecules against the emerging aging-related diseases such as Parkinson's, Alzheimer's and Huntington's.

  17. Resveratrol in mammals: effects on aging biomarkers, age-related diseases, and life span.

    Science.gov (United States)

    Marchal, Julia; Pifferi, Fabien; Aujard, Fabienne

    2013-07-01

    Through its antioxidant, anticarcinogenic, and anti-inflammatory properties, resveratrol has become a candidate for drug development in the context of aging studies. Scientific evidence has highlighted its potential as a therapeutic agent for cardiovascular diseases and some cancers but also as an antiaging molecule. Resveratrol is thought to mimic the beneficial effects of chronic and moderate calorie restriction. Nevertheless, no study has demonstrated the prolongation of life span in healthy nonobese mammal models. This review summarizes recent findings on the effects of resveratrol on aging and life span in mammals. In our opinion, more studies should be performed to assess the effects of a chronic dietary intake of resveratrol in long-lived species close to humans, such as nonhuman primates. This will certainly generate more evidence about the ability of resveratrol to achieve the physiological benefits that have been observed in small mammal laboratory models and feature the eventual unwanted secondary effects that may occur under high levels of resveratrol.

  18. NAD⁺ repletion improves mitochondrial and stem cell function and enhances life span in mice.

    Science.gov (United States)

    Zhang, Hongbo; Ryu, Dongryeol; Wu, Yibo; Gariani, Karim; Wang, Xu; Luan, Peiling; D'Amico, Davide; Ropelle, Eduardo R; Lutolf, Matthias P; Aebersold, Ruedi; Schoonjans, Kristina; Menzies, Keir J; Auwerx, Johan

    2016-06-17

    Adult stem cells (SCs) are essential for tissue maintenance and regeneration yet are susceptible to senescence during aging. We demonstrate the importance of the amount of the oxidized form of cellular nicotinamide adenine dinucleotide (NAD(+)) and its effect on mitochondrial activity as a pivotal switch to modulate muscle SC (MuSC) senescence. Treatment with the NAD(+) precursor nicotinamide riboside (NR) induced the mitochondrial unfolded protein response and synthesis of prohibitin proteins, and this rejuvenated MuSCs in aged mice. NR also prevented MuSC senescence in the mdx (C57BL/10ScSn-Dmd(mdx)/J) mouse model of muscular dystrophy. We furthermore demonstrate that NR delays senescence of neural SCs and melanocyte SCs and increases mouse life span. Strategies that conserve cellular NAD(+) may reprogram dysfunctional SCs and improve life span in mammals.

  19. Basic traits predict the prevalence of personality disorder across the life span: the example of psychopathy.

    Science.gov (United States)

    Vachon, David D; Lynam, Donald R; Widiger, Thomas A; Miller, Joshua D; McCrae, Robert R; Costa, Paul T

    2013-05-01

    Personality disorders (PDs) may be better understood in terms of dimensions of general personality functioning rather than as discrete categorical conditions. Personality-trait descriptions of PDs are robust across methods and settings, and PD assessments based on trait measures show good construct validity. The study reported here extends research showing that basic traits (e.g., impulsiveness, warmth, straightforwardness, modesty, and deliberation) can re-create the epidemiological characteristics associated with PDs. Specifically, we used normative changes in absolute trait levels to simulate age-related differences in the prevalence of psychopathy in a forensic setting. Results demonstrated that trait information predicts the rate of decline for psychopathy over the life span; discriminates the decline of psychopathy from that of a similar disorder, antisocial PD; and accurately predicts the differential decline of subfactors of psychopathy. These findings suggest that basic traits provide a parsimonious account of PD prevalence across the life span.

  20. The decline of verbal and visuospatial working memory across the adult life span

    OpenAIRE

    Cansino, Selene; Hernández-Ramos, Evelia; Estrada-Manilla, Cinthya; Torres-Trejo, Frine; Martínez-Galindo, Joyce Graciela; Ayala-Hernández, Mariana; Gómez-Fernández, Tania; Osorio, David; Cedillo-Tinoco, Melisa; Garcés-Flores, Lissete; Beltrán-Palacios, Karla; García-Lázaro, Haydée Guadalupe; García-Gutiérrez, Fabiola; Cadena-Arenas, Yadira; Fernández-Apan, Luisa

    2013-01-01

    It has been well established that working memory abilities decrease with advancing age; however, the specific time point in the adult life span at which this deficit begins and the rate at which it advances are still controversial. There is no agreement on whether working memory declines equally for visuospatial and verbal information, and the literature disagrees on how task difficulty may influence this decay. We addressed these questions in a lifespan sample of 1,500 participants between 2...

  1. Life-Span Differences in the Uses and Gratifications of Tablets: Implications for Older Adults.

    Science.gov (United States)

    Magsamen-Conrad, Kate; Dowd, John; Abuljadail, Mohammad; Alsulaiman, Saud; Shareefi, Adnan

    2015-11-01

    This study extends Uses and Gratifications theory by examining the uses and gratifications of a new technological device, the tablet computer, and investigating the differential uses and gratifications of tablet computers across the life-span. First, we utilized a six-week tablet training intervention to adapt and extend existing measures to the tablet as a technological device. Next, we used paper-based and online surveys (N=847), we confirmed four main uses of tablets: 1) Information Seeking, 2) Relationship Maintenance, 3) Style, 4) Amusement and Killing time, and added one additional use category 5) Organization. We discovered differences among the five main uses of tablets across the life-span, with older adults using tablets the least overall. Builders, Boomers, GenX and GenY all reported the highest means for information seeking. Finally, we used a structural equation model to examine how uses and gratifications predicts hours of tablet use. The study provides limitations and suggestions for future research and marketers. In particular, this study offers insight to the relevancy of theory as it applies to particular information and communication technologies and consideration of how different periods in the life-span affect tablet motivations.

  2. Trade-off between cellular immunity and life span in mealworm beetles Tenebrio molitor

    Institute of Scientific and Technical Information of China (English)

    Indrikis KRAMS; Jan(i)na DAUK(S)TE; Inese KIVLENIECE; Ants KAASIK; Tatjana KRAMA; Todd M.FREEBERG; Markus J.RANTALA

    2013-01-01

    Encapsulation is a nonspecific,cellular response through which insects defend themselves against multicellular pathogens.During this immune reaction,haemocytes recognize an object as foreign and cause other haemocytes to aggregate and form a capsule around the object,often consisting of melanized cells.The process of melanisation is accompanied by the formation of potentially toxic reactive oxygen species,which can kill not only pathogens but also host cells.In this study we tested whether the encapsulation response is costly in mealworm beetles Tenebrio molitor.We found a negative relationship between the duration of implantation via a nylon monofilament and remaining life span.We also found a negative relationship between the strength of immune response and remaining life span,suggesting that cellular immunity is costly in T.molitor,and that there is a trade-off between immune response and remaining life span.However,this relationship disappeared at 31-32 hours of implantation at 25 ± 2℃.As the disappearance of a relationship between duration of implantation and lifespan coincided with the highest values of encapsulation response,we concluded that the beetles stopped investment in the production of melanotic cells,as the implant,a synthetic parasite,was fully isolated from the host's tissues.

  3. Trade-off between cellular immunity and life span in mealworm beetles Tenebrio molitor

    Directory of Open Access Journals (Sweden)

    Indrikis KRAMS, Janīna DAUKŠTE, Inese KIVLENIECE, Ants KAASIK, Tatjana KRAMA, Todd M. REEBERG, Markus J. RANTALA

    2013-06-01

    Full Text Available Encapsulation is a nonspecific, cellular response through which insects defend themselves against multicellular pathogens. During this immune reaction, haemocytes recognize an object as foreign and cause other haemocytes to aggregate and form a capsule around the object, often consisting of melanized cells. The process of melanisation is accompanied by the formation of potentially toxic reactive oxygen species, which can kill not only pathogens but also host cells. In this study we tested whether the encapsulation response is costly in mealworm beetles Tenebrio molitor. We found a negative relationship between the duration of implantation via a nylon monofilament and remaining life span. We also found a negative relationship between the strength of immune response and remaining life span, suggesting that cellular immunity is costly in T. molitor, and that there is a trade-off between immune response and remaining life span. However, this relationship disappeared at 31-32 hours of implantation at 25 ± 2℃. As the disappearance of a relationship between duration of implantation and lifespan coincided with the highest values of encapsulation response, we concluded that the beetles stopped investment in the production of melanotic cells, as the implant, a synthetic parasite, was fully isolated from the host’s tissues [Current Zoology 59 (3: 340–346, 2013].

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

    Science.gov (United States)

    Patalano, F

    2000-04-01

    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.).

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

    Science.gov (United States)

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

    2009-01-01

    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…

  6. Life span and reproductive cost explain interspecific variation in the optimal onset of reproduction.

    Science.gov (United States)

    Mourocq, Emeline; Bize, Pierre; Bouwhuis, Sandra; Bradley, Russell; Charmantier, Anne; de la Cruz, Carlos; Drobniak, Szymon M; Espie, Richard H M; Herényi, Márton; Hötker, Hermann; Krüger, Oliver; Marzluff, John; Møller, Anders P; Nakagawa, Shinichi; Phillips, Richard A; Radford, Andrew N; Roulin, Alexandre; Török, János; Valencia, Juliana; van de Pol, Martijn; Warkentin, Ian G; Winney, Isabel S; Wood, Andrew G; Griesser, Michael

    2016-02-01

    Fitness can be profoundly influenced by the age at first reproduction (AFR), but to date the AFR-fitness relationship only has been investigated intraspecifically. Here, we investigated the relationship between AFR and average lifetime reproductive success (LRS) across 34 bird species. We assessed differences in the deviation of the Optimal AFR (i.e., the species-specific AFR associated with the highest LRS) from the age at sexual maturity, considering potential effects of life history as well as social and ecological factors. Most individuals adopted the species-specific Optimal AFR and both the mean and Optimal AFR of species correlated positively with life span. Interspecific deviations of the Optimal AFR were associated with indices reflecting a change in LRS or survival as a function of AFR: a delayed AFR was beneficial in species where early AFR was associated with a decrease in subsequent survival or reproductive output. Overall, our results suggest that a delayed onset of reproduction beyond maturity is an optimal strategy explained by a long life span and costs of early reproduction. By providing the first empirical confirmations of key predictions of life-history theory across species, this study contributes to a better understanding of life-history evolution.

  7. Life span, reproductive output, and reproductive opportunity in captive Goeldi's monkeys (Callimico goeldii).

    Science.gov (United States)

    Nuss, Kara; Warneke, Mark

    2010-01-01

    In the absence of long-term field studies, demographic and reproductive records from animals housed in zoos and research laboratories are a valuable tool for the study of life history variables relating to reproduction. In this study, we analyzed studbook records of more than 2,000 individuals born over a 40-year period (1965-2004) to describe life history patterns of captive Goeldi's monkeys (Callimico goeldii) housed in North America and Europe. Using Kaplan-Meier survival analysis methods, we found the mean life span to be 5.5 years. The rate of infant mortality, defined as death before 30 days, was approximately 30%, with European animals being more likely to survive infancy than North American animals. When individuals surviving at least 1.5 years are considered, lifetime reproductive output averaged 3.5 offspring, yet more than one-third of individuals did not produce any offspring. Using a smaller dataset of individuals with known pairing histories, we developed a measure of opportunity for reproduction (OFR), which represented the total time an individual was known to be housed with a potential mate. For both sexes, we found that the correlation between OFR and number of offspring produced was much higher than the correlation between life span and number of offspring produced. This result highlights the importance of taking into account an individual's OFR. As a whole, our findings help characterize the life histories of captive Goeldi's monkeys and emphasize the impact management practices may have on reproductive success.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1982-10-01

    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.

  9. Resilience, according to the paradigm of the development along the life (life-span)

    OpenAIRE

    Arlete Portella Fontes

    2010-01-01

    Resilience, in the approach of the development along the life, refers to the capacity of recovering and maintenance of the adaptive behavior when the person feels threatened by any distressing event (Staudinger, Marsiske and Baltes, 1995). Although the losses become more likely than the developed gains, the aged people can present considerable stability, self-esteem, competence, self-efficacy, subjective quality of life. The resilience is based on active protecting resources along the life: m...

  10. Dead or alive: deformed wing virus and Varroa destructor reduce the life span of winter honeybees.

    Science.gov (United States)

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

    2012-02-01

    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.

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

    Science.gov (United States)

    Alterovitz, Sheyna Sears-Roberts; Mendelsohn, Gerald A

    2009-06-01

    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.

  12. The life span-prolonging effect of sirtuin-1 is mediated by autophagy.

    Science.gov (United States)

    Morselli, Eugenia; Maiuri, Maria Chiara; Markaki, Maria; Megalou, Evgenia; Pasparaki, Angela; Palikaras, Konstantinos; Criollo, Alfredo; Galluzzi, Lorenzo; Malik, Shoaib Ahmad; Vitale, Ilio; Michaud, Mickael; Madeo, Frank; Tavernarakis, Nektarios; Kroemer, Guido

    2010-01-01

    The life span of various model organisms can be extended by caloric restriction as well as by autophagy-inducing pharmacological agents. Life span-prolonging effects have also been observed in yeast cells, nematodes and flies upon the overexpression of the deacetylase Sirtuin-1. Intrigued by these observations and by the established link between caloric restriction and Sirtuin-1 activation, we decided to investigate the putative implication of Sirtuin-1 in the response of human cancer cells and Caenorhabditis elegans to multiple triggers of autophagy. Our data indicate that the activation of Sirtuin-1 (by the pharmacological agent resveratrol and/or genetic means) per se ignites autophagy, and that Sirtuin-1 is required for the autophagic response to nutrient deprivation, in both human and nematode cells, but not for autophagy triggered by downstream signals such as the inhibition of mTOR or p53. Since the life spanextending effects of Sirtuin-1 activators are lost in autophagy-deficient C. elegans, our results suggest that caloric restriction and resveratrol extend longevity, at least in experimental settings, by activating autophagy.

  13. From children to adults: motor performance across the life-span.

    Directory of Open Access Journals (Sweden)

    Jonas S R Leversen

    Full Text Available The life-span approach to development provides a theoretical framework to examine the general principles of life-long development. This study aims to investigate motor performance across the life span. It also aims to investigate if the correlations between motor tasks increase with aging. A cross-sectional design was used to describe the effects of aging on motor performance across age groups representing individuals from childhood to young adult to old age. Five different motor tasks were used to study changes in motor performance within 338 participants (7-79 yrs. Results showed that motor performance increases from childhood (7-9 to young adulthood (19-25 and decreases from young adulthood (19-25 to old age (66-80. These results are mirroring results from cognitive research. Correlation increased with increasing age between two fine motor tasks and two gross motor tasks. We suggest that the findings might be explained, in part, by the structural changes that have been reported to occur in the developing and aging brain and that the theory of Neural Darwinism can be used as a framework to explain why these changes occur.

  14. Increasing cell culture population doublings for long-term growth of finite life span human cell cultures

    Science.gov (United States)

    Stampfer, Martha R; Garbe, James C

    2015-02-24

    Cell culture media formulations for culturing human epithelial cells are herein described. Also described are methods of increasing population doublings in a cell culture of finite life span human epithelial cells and prolonging the life span of human cell cultures. Using the cell culture media disclosed alone and in combination with addition to the cell culture of a compound associated with anti-stress activity achieves extended growth of pre-stasis cells and increased population doublings and life span in human epithelial cell cultures.

  15. Increasing cell culture population doublings for long-term growth of finite life span human cell cultures

    Energy Technology Data Exchange (ETDEWEB)

    Stampfer, Martha R.; Garbe, James C.

    2016-06-28

    Cell culture media formulations for culturing human epithelial cells are herein described. Also described are methods of increasing population doublings in a cell culture of finite life span human epithelial cells and prolonging the life span of human cell cultures. Using the cell culture media disclosed alone and in combination with addition to the cell culture of a compound associated with anti-stress activity achieves extended growth of pre-stasis cells and increased population doublings and life span in human epithelial cell cultures.

  16. Gender, Race, and Age: The Content of Compound Stereotypes Across the Life Span.

    Science.gov (United States)

    Andreoletti, Carrie; Leszczynski, Jennifer P; Disch, William B

    2015-07-01

    While stereotypes about gender, race, and age (particularly old age) have been studied independently, few have examined the content of compound stereotypes that consider the intersection of gender, race, and age. Using a within-subjects design, we examined stereotypes as a function of target gender (male, female), race (Black, White), and age across the life span (adolescent, young adult, middle-aged, young-old, and old-old). Participants rated 20 target groups on 10 attributes representative of either an agentic (e.g., ambitious) or communal (e.g., considerate) orientation. Participants were presented only with categorical information (e.g., Black, 85-year-old, males), and ordering of categorical information and target groups was counterbalanced across participants. We hypothesized differential effects of target gender and race as a function of age. Multivariate analyses of variance on each attribute revealed significant main effects that supported traditional stereotype research, but significant interactions revealed a more complicated picture. Overall, results showed that while gender stereotypes about agency and communion generally hold up across the life span, they are more applicable to White than Black targets. Results also supported the notion that we hold unique stereotypes based on multiple social categories rather than simply perceiving one social category as more salient than another, which was best exemplified in the case of Black female targets that were less likely to be perceived in gender stereotypic ways across the life span. We suggest stereotype research needs to shift to accommodate for the complexity and diversity of real people.

  17. Resveratrol Attenuates Oxidative Stress and Extends Life Span in the Annual Fish Nothobranchius guentheri.

    Science.gov (United States)

    Liu, Tingting; Qi, He; Ma, Long; Liu, Zhaojun; Fu, Huiling; Zhu, Wenzhen; Song, Taiyu; Yang, Bingwu; Li, Guorong

    2015-06-01

    Resveratrol is a natural polyphenol derived mainly from the skin of grapes and from red wine. Resveratrol prolongs life span in several invertebrates, but this function is not found in mice. Our recently published paper demonstrated that resveratrol prolonged longevity of the annual fish Nothobranchius guentheri, a promising vertebrate model for anti-aging research. However, the anti-aging process by resveratrol remains largely unexplored, and little is known about its effects on oxidative stress. In this study, by long-term supplementation of resveratrol from sexual maturity onward in the annual fish, we detected survivorship and oxidative stress at three different developmental stages in vivo. A total of 112 fish were fed with resveratrol in the concentration of 200 μg/gram food and 111 fish without resveratrol from 16 weeks of age until to the end of their lives. The mean and maximum life spans of the fish treated with resveratrol were extended by 17.34% and 17.66%, respectively, compared to the fish in control group. The markers of oxidative stress, such as the levels of reactive oxygen species (ROS), the activities of anti-oxidant enzymes, and the degree of oxidative damage, were detected at 6, 9, and 12 months, respectively. The results showed that levels of ROS and oxidative damage increased and activities of anti-oxidant enzymes appeared to decrease with age. Resveratrol treatment significantly attenuated the increase of ROS and oxidative damage and up-regulated the decrease of anti-oxidant enzyme activities induced by aging. Our results demonstrated that resveratrol decreased oxidative stress and extended life span in this short-lived fish.

  18. Life-span of classical solutions for one-dimensional hydromagnetic flow

    Institute of Scientific and Technical Information of China (English)

    LIU Fa-gui

    2007-01-01

    The paper concerns Cauchy problem for one-dimensional hydromagnetic dynamics with dissipative terms. When the dissipation coefficient is equal to zero it is shown that the smooth solutions develop shocks in the finite time if the initial amounts of entropy and magnetic field are smaller than those of sound waves; when it is larger than zero, and the initial amounts of entropy, this dissipation coefficient and the magnetic field in each period are smaller than those of sound waves, then the smooth solutions blow up in the finite time. Moreover, the life-span of the smooth solution is given.

  19. Sexual orientation across the life span: introduction to the special section.

    Science.gov (United States)

    Patterson, Charlotte J

    2008-01-01

    What impact does sexual orientation have on human development over the life span? As questions related to sexual orientation have become increasingly topics of public discussion and debate in recent years, psychological study of the issues has also burgeoned. What was once a new frontier for research has matured into a large, complex, and rapidly growing area of knowledge. Important research is being conducted on many issues, by diverse investigators, from a number of theoretical perspectives, in many parts of the world. The articles in this special section provide only a sampling of current research, but they begin to suggest the vitality and excitement of a field that is coming into its own.

  20. Causes of decreased life expectancy over the life span in bipolar disorder

    DEFF Research Database (Denmark)

    Kessing, Lars Vedel; Vradi, Eleni; McIntyre, Roger S

    2015-01-01

    BACKGROUND: Accelerated aging has been proposed as a mechanism explaining the increased prevalence of comorbid general medical illnesses in bipolar disorder. AIMS: To test the hypothesis that lost life years due to natural causes starts in early and mid-adulthood, supporting the hypothesis...... of accelerated aging. METHODS: Using individual data from nationwide registers of patient with a diagnosis of bipolar disorder we calculated remaining life expectancies before age 90 years for values of age 15, 25, 35…75 years among all individuals alive in year 2000. Further, we estimated the reduction in life...... expectancy due to natural causes (physical illnesses) and unnatural causes (suicide and accidents) in relation to age. RESULTS: A total of 22,635 patients with bipolar disorder were included in the study in addition to data from the entire Danish general population of 5.4 million people. At age 15 years...

  1. Resilience, according to the paradigm of the development along the life (life-span

    Directory of Open Access Journals (Sweden)

    Arlete Portella Fontes

    2010-10-01

    Full Text Available Resilience, in the approach of the development along the life, refers to the capacity of recovering and maintenance of the adaptive behavior when the person feels threatened by any distressing event (Staudinger, Marsiske and Baltes, 1995. Although the losses become more likely than the developed gains, the aged people can present considerable stability, self-esteem, competence, self-efficacy, subjective quality of life. The resilience is based on active protecting resources along the life: mechanisms of self-regulation, self-efficacy, emotional regulation, mechanisms of stress oping, selection strategies, optimization and compensation of the domains of human functioning. At the end of the article, interventions to increase the resilience of the aged are suggested.

  2. Exposure To Harmful Workplace Practices Could Account For Inequality In Life Spans Across Different Demographic Groups.

    Science.gov (United States)

    Goh, Joel; Pfeffer, Jeffrey; Zenios, Stefanos

    2015-10-01

    The existence of important socioeconomic disparities in health and mortality is a well-established fact. Many pathways have been adduced to explain inequality in life spans. In this article we examine one factor that has been somewhat neglected: People with different levels of education get sorted into jobs with different degrees of exposure to workplace attributes that contribute to poor health. We used General Social Survey data to estimate differential exposures to workplace conditions, results from a meta-analysis that estimated the effect of workplace conditions on mortality, and a model that permitted us to estimate the overall effects of workplace practices on health. We conclude that 10-38 percent of the difference in life expectancy across demographic groups can be explained by the different job conditions their members experience.

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

    NARCIS (Netherlands)

    May, C.M.; Doroszuk, A.; Zwaan, B.J.

    2015-01-01

    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

  4. Studies on the life span, reproduction, tissue biochemistry and diesel oil toxicity in the estuarine cladocera Diaphanosoma celebensis

    Digital Repository Service at National Institute of Oceanography (India)

    PrabhuKonkar, S.R.; Achuthankutty, C.T.

    Diaphanosoma celebensis Stingelin is a typical estuarine cladocera, reported for the first time in India from the Mandovi estuary of Goa, India. The results of the study made on the laboratory reared specimens of this species on the life span...

  5. Materialism across the life span: An age-period-cohort analysis.

    Science.gov (United States)

    Jaspers, Esther D T; Pieters, Rik G M

    2016-09-01

    This research examined the development of materialism across the life span. Two initial studies revealed that (a) lay beliefs were that materialism declines with age and (b) previous research findings also implied a modest, negative relationship between age and materialism. Yet, previous research has considered age only as a linear control variable, thereby precluding the possibility of more intricate relationships between age and materialism. Moreover, prior studies have relied on cross-sectional data and thus confound age and cohort effects. To improve on this, the main study used longitudinal data from 8 waves spanning 9 years of over 4,200 individuals (16 to 90 years) to examine age effects on materialism while controlling for cohort and period effects. Using a multivariate multilevel latent growth model, it found that materialism followed a curvilinear trajectory across the life span, with the lowest levels at middle age and higher levels before and after that. Thus, in contrast to lay beliefs, materialism increased in older age. Moreover, age effects on materialism differed markedly between 3 core themes of materialism: acquisition centrality, possession-defined success, and acquisition as the pursuit of happiness. In particular, acquisition centrality and possession-defined success were higher at younger and older age. Independent of these age effects, older birth cohorts were oriented more toward possession-defined success, whereas younger birth cohorts were oriented more toward acquisition centrality. The economic downturn since 2008 led to a decrease in acquisition as the pursuit of happiness and in desires for personal growth, but to an increase in desires for achievement. (PsycINFO Database Record

  6. New tetradecyltrimethylammonium-selective electrodes: surface composition and topography as correlated with electrode's life span.

    Science.gov (United States)

    Marafie, Hayat M; Al-Shammari, Tahani F; Shoukry, Adel F

    2012-03-15

    Two conventional plastic membrane electrodes that are selective for the tetradecyltrimethylammonium cation (TTA) have been prepared. The ion exchangers of these sensors were the ion associate, TTA-PT, and the ion aggregate, TTA-PSS, where PT and PSS are phosphotungstate and polystyrene sulfonate, respectively. The following performance characteristics of the TTA-PT- and TTA-PSS-containing electrodes were found: conditioning time of 30 and 20 min; potential response of 58.2 and 61.1 mV/TTA concentration decade; rectilinear concentration ranges of 2.0 × 10(-5)-5.0 × 10(-2) and 1.5 × 10(-5)-7.9 × 10(-2) mol L(-1); average working pH ranges of 4.0-10.5 and 3.8-10.7; life spans of 20 and 28 weeks, and isothermal temperature coefficients of 4.44 × 10(-4) and 6.10 × 10(-4)V/°C, respectively. Both electrodes exhibited high selectivity for TTA with an increasing number of inorganic and quaternary ammonium surfactant cations. These electrodes have been successfully applied to assay an antiseptic formulation containing TTA. Surface analyses using electron microscopy and X-ray photoelectron spectroscopy were used to determine the cause of the limited life span of plastic membrane electrodes.

  7. AMPKalpha1 deletion shortens erythrocyte life span in mice: role of oxidative stress.

    Science.gov (United States)

    Wang, Shaobin; Dale, George L; Song, Ping; Viollet, Benoit; Zou, Ming-Hui

    2010-06-25

    AMP-activated protein kinase (AMPK) is an energy sensor essential for maintaining cellular energy homeostasis. Here, we report that AMPKalpha1 is the predominant isoform of AMPK in murine erythrocytes and mice globally deficient in AMPKalpha1 (AMPKalpha1(-/-)), but not in those lacking AMPKalpha2, and the mice had markedly enlarged spleens with dramatically increased proportions of Ter119-positive erythroid cells. Blood tests revealed significantly decreased erythrocyte and hemoglobin levels with increased reticulocyte counts and elevated plasma erythropoietin concentrations in AMPKalpha1(-/-) mice. The life span of erythrocytes from AMPKalpha1(-/-) mice was less than that in wild-type littermates, and the levels of reactive oxygen species and oxidized proteins were significantly increased in AMPKalpha1(-/-) erythrocytes. In keeping with the elevated oxidative stress, treatment of AMPKalpha1(-/-) mice with the antioxidant, tempol, resulted in decreased reticulocyte counts and improved erythrocyte survival. Furthermore, the expression of Foxo3 and reactive oxygen species scavenging enzymes was significantly decreased in erythroblasts from AMPKalpha1(-/-) mice. Collectively, these results establish an essential role for AMPKalpha1 in regulating oxidative stress and life span in erythrocytes.

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

    Science.gov (United States)

    Schubert, Christian

    2014-05-01

    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.

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

    Science.gov (United States)

    Strait, Dana L; Kraus, Nina

    2014-02-01

    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 in which to study mechanisms of experience-dependent changes in human auditory function.

  10. The Verriest Lecture: Short-wave-sensitive cone pathways across the life span.

    Science.gov (United States)

    Werner, John S

    2016-03-01

    Structurally and functionally, the short-wave-sensitive (S) cone pathways are thought to decline more rapidly with normal aging than the middle- and long-wave-sensitive cone pathways. This would explain the celebrated results by Verriest and others demonstrating that the largest age-related color discrimination losses occur for stimuli on a tritan axis. Here, we challenge convention, arguing from psychophysical data that selective S-cone pathway losses do not cause declines in color discrimination. We show substantial declines in chromatic detection and discrimination, as well as in temporal and spatial vision tasks, that are mediated by S-cone pathways. These functional losses are not, however, unique to S-cone pathways. Finally, despite reduced photon capture by S cones, their postreceptoral pathways provide robust signals for the visual system to renormalize itself to maintain nearly stable color perception across the life span.

  11. Estimates for the number of visible galaxy-spanning civilizations and the cosmological expansion of life

    CERN Document Server

    Olson, S Jay

    2015-01-01

    If advanced civilizations appear in the universe with a desire to expand, the entire universe can become saturated with life on a short timescale, even if such expanders appear but rarely. Our presence in an untouched Milky Way thus constrains the appearance rate of galaxy-spanning Kardashev type III (K3) civilizations, if it is assumed that some fraction of K3 civilizations will continue their expansion at intergalactic distances. We use this constraint to estimate the appearance rate of K3 civilizations for 81 cosmological scenarios by specifying the extent to which humanity could be a statistical outlier. We find that in nearly all plausible scenarios, the distance to the nearest visible K3 is cosmological. In searches where the observable range is limited, we also find that the most likely detections tend to be expanding civilizations who have entered the observable range from farther away. An observation of K3 clusters is thus more likely than isolated K3 galaxies.

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

    Directory of Open Access Journals (Sweden)

    Veronique D Bohbot

    2012-11-01

    Full Text Available This study sought to investigate navigational strategies across the life span, by testing 8-year old children to 80-year 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 grey 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 downside 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 grey 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.

  13. Age- and calorie-independent life span extension from dietary restriction by bacterial deprivation in Caenorhabditis elegans

    Directory of Open Access Journals (Sweden)

    Sager Jennifer

    2008-05-01

    Full Text Available Abstract Background Dietary restriction (DR increases life span and delays age-associated disease in many organisms. The mechanism by which DR enhances longevity is not well understood. Results Using bacterial food deprivation as a means of DR in C. elegans, we show that transient DR confers long-term benefits including stress resistance and increased longevity. Consistent with studies in the fruit fly and in mice, we demonstrate that DR also enhances survival when initiated late in life. DR by bacterial food deprivation significantly increases life span in worms when initiated as late as 24 days of adulthood, an age at which greater than 50% of the cohort have died. These survival benefits are, at least partially, independent of food consumption, as control fed animals are no longer consuming bacterial food at this advanced age. Animals separated from the bacterial lawn by a barrier of solid agar have a life span intermediate between control fed and food restricted animals. Thus, we find that life span extension from bacterial deprivation can be partially suppressed by a diffusible component of the bacterial food source, suggesting a calorie-independent mechanism for life span extension by dietary restriction. Conclusion Based on these findings, we propose that dietary restriction by bacterial deprivation increases longevity in C. elegans by a combination of reduced food consumption and decreased food sensing.

  14. A shorter 146Sm half-life measured and implications for 146Sm-142Nd chronology in the solar system.

    Science.gov (United States)

    Kinoshita, N; Paul, M; Kashiv, Y; Collon, P; Deibel, C M; DiGiovine, B; Greene, J P; Henderson, D J; Jiang, C L; Marley, S T; Nakanishi, T; Pardo, R C; Rehm, K E; Robertson, D; Scott, R; Schmitt, C; Tang, X D; Vondrasek, R; Yokoyama, A

    2012-03-30

    The extinct p-process nuclide (146)Sm serves as an astrophysical and geochemical chronometer through measurements of isotopic anomalies of its α-decay daughter (142)Nd. Based on analyses of (146)Sm/(147)Sm α-activity and atom ratios, we determined the half-life of (146)Sm to be 68 ± 7 (1σ) million years, which is shorter than the currently used value of 103 ± 5 million years. This half-life value implies a higher initial (146)Sm abundance in the early solar system, ((146)Sm/(144)Sm)(0) = 0.0094 ± 0.0005 (2σ), than previously estimated. Terrestrial, lunar, and martian planetary silicate mantle differentiation events dated with (146)Sm-(142)Nd converge to a shorter time span and in general to earlier times, due to the combined effect of the new (146)Sm half-life and ((146)Sm/(144)Sm)(0) values.

  15. Dietary resveratrol prevents Alzheimer's markers and increases life span in SAMP8.

    Science.gov (United States)

    Porquet, David; Casadesús, Gemma; Bayod, Sergi; Vicente, Alberto; Canudas, Anna M; Vilaplana, Jordi; Pelegrí, Carme; Sanfeliu, Coral; Camins, Antoni; Pallàs, Mercè; del Valle, Jaume

    2013-10-01

    Resveratrol is a polyphenol that is mainly found in grapes and red wine and has been reported to be a caloric restriction (CR) mimetic driven by Sirtuin 1 (SIRT1) activation. Resveratrol increases metabolic rate, insulin sensitivity, mitochondrial biogenesis and physical endurance, and reduces fat accumulation in mice. In addition, resveratrol may be a powerful agent to prevent age-associated neurodegeneration and to improve cognitive deficits in Alzheimer's disease (AD). Moreover, different findings support the view that longevity in mice could be promoted by CR. In this study, we examined the role of dietary resveratrol in SAMP8 mice, a model of age-related AD. We found that resveratrol supplements increased mean life expectancy and maximal life span in SAMP8 and in their control, the related strain SAMR1. In addition, we examined the resveratrol-mediated neuroprotective effects on several specific hallmarks of AD. We found that long-term dietary resveratrol activates AMPK pathways and pro-survival routes such as SIRT1 in vivo. It also reduces cognitive impairment and has a neuroprotective role, decreasing the amyloid burden and reducing tau hyperphosphorylation.

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

    Science.gov (United States)

    Seydel, Jennifer

    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.

  17. Chips in black boxes? Convenience life span, parafood, brandwidth, families, and co-creation.

    Science.gov (United States)

    Jacobs, Marc

    2015-11-01

    Any consumer who opens a bag of potato or corn chips (or crisps in the UK) knows there is no time to waste to enjoy or share them. The convenience life span of chips is limited: it is the shelf or storage life and a very limited time once outside the bag. Many technologies converge to generate the desired effect as a black box, not only of the packaging but also of the chips themselves. The concept of paratext can be applied to printed messages on the package, including the brand name and other texts like advertising (epitexts), which can be expanded into the concept of parafood. These concepts help to discuss technological developments and interpret why this has recently become a negotiation zone for co-creation (see the Do us a flavor campaigns). They are symptoms of changing relations between production, research and development, marketing, and consumption. This paper pays special attention to back stories, underdog brand biographies and narratives about origin. The concept of brandwidth is introduced to sensitize about the limits of combining different stories about chips. A recent brand biography, a family history and a cookery book are used to discuss the phenomenon of cooking with Fritos. Together with the concepts of parafood, brandwidth and black boxes, more reflection and dialogue about the role of history and heritage in marketing put new challenging perspectives on the agenda.

  18. Refugees 's experiences across a life span : a qualitative study of perceived resources and demands among Iranian refugees in Norway

    OpenAIRE

    Sattarzadeh, Solmaz

    2009-01-01

    This study explored the experiences of Iranian refugees across their life span in Norway. More specifically, the aim was to identify what resources and demands were encountered in each period of the asylum seeking, the resettlement, and the present life of Iranian refugees and how participants perceived and experienced these resources and demands. A qualitative approach, was used to capture in detail the life experiences of individuals. Nine Iranian refugees coming to Norway as asylum seekers...

  19. Sex-specific Tradeoffs With Growth and Fitness Following Life-span Extension by Rapamycin in an Outcrossing Nematode, Caenorhabditis remanei.

    Science.gov (United States)

    Lind, Martin I; Zwoinska, Martyna K; Meurling, Sara; Carlsson, Hanne; Maklakov, Alexei A

    2016-07-01

    Rapamycin inhibits the nutrient-sensing TOR pathway and extends life span in a wide range of organisms. Although life-span extension usually differs between the sexes, the reason for this is poorly understood. Because TOR influences growth, rapamycin likely affects life-history traits such as growth and reproduction. Sexes have different life-history strategies, and theory predicts that they will resolve the tradeoffs between growth, reproduction, and life span differently. Specifically, in taxa with female-biased sexual size dimorphism, reduced growth may have smaller effects on male fitness. We investigated the effects of juvenile, adult, or life-long rapamycin treatment on growth, reproduction, life span, and individual fitness in the outcrossing nematode Caenorhabditis remanei Life-long exposure to rapamycin always resulted in the strongest response, whereas postreproductive exposure did not affect life span. Although rapamycin resulted in longer life span and smaller size in males, male individual fitness was not affected. In contrast, size and fitness were negatively affected in females, whereas life span was only extended under high rapamycin concentrations. Our results support the hypothesis that rapamycin affects key life-history traits in a sex-specific manner. We argue that the fitness cost of life-span extension will be sex specific and propose that the smaller sex generally pay less while enjoying stronger life-span increase.

  20. Genetic regulation of life span, metabolism, and body weight in Pohn, a new wild-derived mouse strain.

    Science.gov (United States)

    Yuan, Rong; Flurkey, Kevin; Meng, Qingying; Astle, Mike C; Harrison, David E

    2013-01-01

    Quantitative trait loci (QTL) of longevity identified in human and mouse are significantly colocalized, suggesting that common mechanisms are involved. However, the limited number of strains that have been used in mouse longevity studies undermines the ability to identify longevity genes. We crossed C57BL/6J mice with a new wild-derived strain, Pohn, and identified two life span QTL-Ls1 and Ls2. Interestingly, homologous human longevity QTL colocalize with Ls1. We also defined new QTL for metabolic heat production and body weight. Both phenotypes are significantly correlated with life span. We found that large clone ratio, an in vitro indicator for cellular senescence, is not correlated with life span, suggesting that cell senescence and intrinsic aging are not always associated. Overall, by using Pohn mice, we identified new QTL for longevity-related traits, thus facilitating the exploration of the genetic regulation of aging.

  1. Resting-State Network Topology Differentiates Task Signals across the Adult Life Span.

    Science.gov (United States)

    Chan, Micaela Y; Alhazmi, Fahd H; Park, Denise C; Savalia, Neil K; Wig, Gagan S

    2017-03-08

    Brain network connectivity differs across individuals. For example, older adults exhibit less segregated resting-state subnetworks relative to younger adults (Chan et al., 2014). It has been hypothesized that individual differences in network connectivity impact the recruitment of brain areas during task execution. While recent studies have described the spatial overlap between resting-state functional correlation (RSFC) subnetworks and task-evoked activity, it is unclear whether individual variations in the connectivity pattern of a brain area (topology) relates to its activity during task execution. We report data from 238 cognitively normal participants (humans), sampled across the adult life span (20-89 years), to reveal that RSFC-based network organization systematically relates to the recruitment of brain areas across two functionally distinct tasks (visual and semantic). The functional activity of brain areas (network nodes) were characterized according to their patterns of RSFC: nodes with relatively greater connections to nodes in their own functional system ("non-connector" nodes) exhibited greater activity than nodes with relatively greater connections to nodes in other systems ("connector" nodes). This "activation selectivity" was specific to those brain systems that were central to each of the tasks. Increasing age was accompanied by less differentiated network topology and a corresponding reduction in activation selectivity (or differentiation) across relevant network nodes. The results provide evidence that connectional topology of brain areas quantified at rest relates to the functional activity of those areas during task. Based on these findings, we propose a novel network-based theory for previous reports of the "dedifferentiation" in brain activity observed in aging.SIGNIFICANCE STATEMENT Similar to other real-world networks, the organization of brain networks impacts their function. As brain network connectivity patterns differ across

  2. Life-span extension by dietary restriction is mediated by NLP-7 signaling and coelomocyte endocytosis in C. elegans.

    Science.gov (United States)

    Park, Sang-Kyu; Link, Christopher D; Johnson, Thomas E

    2010-02-01

    Recent studies have shown that the rate of aging can be modulated by diverse interventions. Dietary restriction is the most widely used intervention to promote longevity; however, the mechanisms underlying the effect of dietary restriction remain elusive. In a previous study, we identified two novel genes, nlp-7 and cup-4, required for normal longevity in Caenorhabditis elegans. nlp-7 is one of a set of neuropeptide-like protein genes; cup-4 encodes an ion-channel involved in endocytosis by coelomocytes. Here, we assess whether nlp-7 and cup-4 mediate longevity increases by dietary restriction. RNAi of nlp-7 or cup-4 significantly reduces the life span of the eat-2 mutant, a genetic model of dietary restriction, but has no effect on the life span of long-lived mutants resulting from reduced insulin/IGF-1 signaling or dysfunction of the mitochondrial electron transport chain. The life-span extension observed in wild-type N2 worms by dietary restriction using bacterial dilution is prevented significantly in nlp-7 and cup-4 mutants. RNAi knockdown of genes encoding candidate receptors of NLP-7 and genes involved in endocytosis by coelomocytes also specifically shorten the life span of the eat-2 mutant. We conclude that two novel pathways, NLP-7 signaling and endocytosis by coelomocytes, are required for life extension under dietary restriction in C. elegans.

  3. Atomic Bomb Survivors Life-Span Study: Insufficient Statistical Power to Select Radiation Carcinogenesis Model.

    Science.gov (United States)

    Socol, Yehoshua; Dobrzyński, Ludwik

    2015-01-01

    The atomic bomb survivors life-span study (LSS) is often claimed to support the linear no-threshold hypothesis (LNTH) of radiation carcinogenesis. This paper shows that this claim is baseless. The LSS data are equally or better described by an s-shaped dependence on radiation exposure with a threshold of about 0.3 Sievert (Sv) and saturation level at about 1.5 Sv. A Monte-Carlo simulation of possible LSS outcomes demonstrates that, given the weak statistical power, LSS cannot provide support for LNTH. Even if the LNTH is used at low dose and dose rates, its estimation of excess cancer mortality should be communicated as 2.5% per Sv, i.e., an increase of cancer mortality from about 20% spontaneous mortality to about 22.5% per Sv, which is about half of the usually cited value. The impact of the "neutron discrepancy problem" - the apparent difference between the calculated and measured values of neutron flux in Hiroshima - was studied and found to be marginal. Major revision of the radiation risk assessment paradigm is required.

  4. Speech rate effects on the processing of conversational speech across the adult life span.

    Science.gov (United States)

    Koch, Xaver; Janse, Esther

    2016-04-01

    This study investigates the effect of speech rate on spoken word recognition across the adult life span. Contrary to previous studies, conversational materials with a natural variation in speech rate were used rather than lab-recorded stimuli that are subsequently artificially time-compressed. It was investigated whether older adults' speech recognition is more adversely affected by increased speech rate compared to younger and middle-aged adults, and which individual listener characteristics (e.g., hearing, fluid cognitive processing ability) predict the size of the speech rate effect on recognition performance. In an eye-tracking experiment, participants indicated with a mouse-click which visually presented words they recognized in a conversational fragment. Click response times, gaze, and pupil size data were analyzed. As expected, click response times and gaze behavior were affected by speech rate, indicating that word recognition is more difficult if speech rate is faster. Contrary to earlier findings, increased speech rate affected the age groups to the same extent. Fluid cognitive processing ability predicted general recognition performance, but did not modulate the speech rate effect. These findings emphasize that earlier results of age by speech rate interactions mainly obtained with artificially speeded materials may not generalize to speech rate variation as encountered in conversational speech.

  5. Dietary intake of Curcuma longa and Emblica officinalis increases life span in Drosophila melanogaster.

    Science.gov (United States)

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

    2014-01-01

    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.

  6. Childhood Adversity, Self-Esteem, and Diurnal Cortisol Profiles Across the Life Span.

    Science.gov (United States)

    Zilioli, Samuele; Slatcher, Richard B; Chi, Peilian; Li, Xiaoming; Zhao, Junfeng; Zhao, Guoxiang

    2016-09-01

    Childhood adversity is associated with poor health outcomes in adulthood; the hypothalamic-pituitary-adrenal (HPA) axis has been proposed as a crucial biological intermediary of these long-term effects. Here, we tested whether childhood adversity was associated with diurnal cortisol parameters and whether this link was partially explained by self-esteem. In both adults and youths, childhood adversity was associated with lower levels of cortisol at awakening, and this association was partially driven by low self-esteem. Further, we found a significant indirect pathway through which greater adversity during childhood was linked to a flatter cortisol slope via self-esteem. Finally, youths who had a caregiver with high self-esteem experienced a steeper decline in cortisol throughout the day compared with youths whose caregiver reported low self-esteem. We conclude that self-esteem is a plausible psychological mechanism through which childhood adversity may get embedded in the activity of the HPA axis across the life span.

  7. The decline of verbal and visuospatial working memory across the adult life span.

    Science.gov (United States)

    Cansino, Selene; Hernández-Ramos, Evelia; Estrada-Manilla, Cinthya; Torres-Trejo, Frine; Martínez-Galindo, Joyce Graciela; Ayala-Hernández, Mariana; Gómez-Fernández, Tania; Osorio, David; Cedillo-Tinoco, Melisa; Garcés-Flores, Lissete; Beltrán-Palacios, Karla; García-Lázaro, Haydée Guadalupe; García-Gutiérrez, Fabiola; Cadena-Arenas, Yadira; Fernández-Apan, Luisa; Bärtschi, Andrea; Rodríguez-Ortiz, María Dolores

    2013-12-01

    It has been well established that working memory abilities decrease with advancing age; however, the specific time point in the adult life span at which this deficit begins and the rate at which it advances are still controversial. There is no agreement on whether working memory declines equally for visuospatial and verbal information, and the literature disagrees on how task difficulty may influence this decay. We addressed these questions in a lifespan sample of 1,500 participants between 21 and 80 years old. The n-back task was used, with letters and circles presented at different positions around an imaginary circle, to evaluate working memory in the verbal and visuospatial domains, respectively. The participants' task was to judge whether the current stimulus matched a stimulus that was shown n trials prior. Both domains were evaluated in two levels of difficulty: 1-back and 2-back. The comparison across decades showed that discrimination in the visuospatial and 1-back tasks started to decline earlier in women than in men; however, discrimination was equal between the sexes in the verbal and 2-back tasks. Performance on tasks in the visuospatial domain exhibited more pronounced decline than in those in the verbal domain. The rate of decline in working memory accuracy was superior in 2-back tasks than in 1-back tasks, independent of the domain. These results revealed that the effects of aging on working memory are less dependent on the type of information and more reliant on the resources demanded by the task.

  8. Effects of kaolin particle films on the life span of an orb-weaver spider.

    Science.gov (United States)

    Benhadi-Marín, Jacinto; Pereira, José Alberto; Santos, Sónia A P

    2016-02-01

    Araniella cucurbitina (Araneae: Araneidae) is a widespread orb-weaver spider commonly found in agroecosystems. Mineral particle films such as kaolin, due to their protective or anti-feeding action, can represent an alternative to pesticides, especially in organic farming systems, but little is known about its effects on A. cucurbitina. Therefore, we tested the effect of kaolin sprays on the life span of A. cucurbitina under laboratory conditions. Four treatments were tested encompassing different exposure routes. Thus, kaolin sprays were applied on (i) the surface, (ii) the prey (fly), (iii) the spider and (iv) both spider & prey. A control group was tested with water in each treatment. Results showed that sprays of kaolin significantly affected the survival of A. curcubitina when applications were done on the surface and on both spider & prey registering a reduction of 48% and 56%, respectively. Spiders in control obtained higher probability of reaching alive at the end of the assay than those treated with kaolin. Differences observed can be explained by the feeding behavior of the species and may depend on the consumption of the web by the spider and the ratio spider/fly for body size.

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

    Science.gov (United States)

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

    2013-05-01

    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.

  10. From Suns to Life: A Chronological Approach to the History of Life on Earth 4. Building of a Habitable Planet

    Science.gov (United States)

    Martin, Hervé; Albarède, Francis; Claeys, Philippe; Gargaud, Muriel; Marty, Bernard; Morbidelli, Alessandro; Pinti, Daniele L.

    2006-06-01

    Except the old Jack Hills zircon crystals, it does not exit direct record of the first 500 Ma of the Earth history. Consequently, the succession of events that took place during this period is only indirectly known through geochemistry, comparison with other telluric planets, and numerical modelling. Just after planetary accretion several episodes were necessary in order to make life apparition and development possible and to make the Earth surface habitable. Among these stages are: the core differentiation, the formation of a magma ocean, the apparition of the first atmosphere, oceans and continents as well as the development of magnetic field and of plate tectonics. In the same time, Earth has been subject to extraterrestrial events such as the Late Heavy Bombardment (LHB) between 3.95 and 3.8 Ga. Since 4.4 4.3 Ga, the conditions for pre-biotic chemistry and appearance of life were already met (liquid water, continental crust, no strong meteoritic bombardment, etc...). This does not mean that life existed as early, but this demonstrates that all necessary conditions assumed for life development were already present on Earth.

  11. Proteomic profiles reveal age-related changes in coelomic fluid of sea urchin species with different life spans.

    Science.gov (United States)

    Bodnar, Andrea

    2013-05-01

    Sea urchins have a different life history from humans and traditional model organisms used to study the process of aging. Sea urchins grow indeterminately, reproduce throughout their life span and some species have been shown to exhibit negligible senescence with no increase in mortality rate at advanced ages. Despite these properties, different species of sea urchins are reported to have very different natural life spans providing a unique model to investigate cellular mechanisms underlying life span determination and negligible senescence. To gain insight into the biological changes that accompany aging in these animals, proteomic profiles were examined in coelomic fluid from young and old sea urchins of three species with different life spans: short-lived Lytechinus variegatus, long-lived Strongylocentrotus franciscanus and Strongylocentrotus purpuratus which has an intermediate life span. The proteomic profiles of cell-free coelomic fluid were complex with many proteins exhibiting different forms and extensive post-translational modifications. Approximately 20% of the protein spots on 2-D gels showed more than two-fold change with age in each of the species. Changes that are consistent with age in all three species may prove to be useful biomarkers for age-determination for these commercially fished marine invertebrates and also may provide clues to mechanisms of negligible senescence. Among the proteins that change with age, the ectodomain of low-density lipoprotein receptor-related protein 4 (LRP4) was significantly increased in the coelomic fluid of all three sea urchin species suggesting that the Wnt signaling pathway should be further investigated for its role in negligible senescence.

  12. Age at menopause, reproductive life span, and type 2 diabetes risk results from the EPIC-interAct Study

    NARCIS (Netherlands)

    Brand, J.S.; Schouw, van der Y.T.; Onland-Moret, N.; Sharp, S.J.; Feskens, E.J.M.

    2013-01-01

    OBJECTIVEAge at menopause is an important determinant of future health outcomes, but little is known about its relationship with type 2 diabetes. We examined the associations of menopausal age and reproductive life span (menopausal age minus menarcheal age) with diabetes risk.RESEARCH DESIGN AND MET

  13. Sustained Attention Across the Life Span in a Sample of 10,000: Dissociating Ability and Strategy.

    Science.gov (United States)

    Fortenbaugh, Francesca C; DeGutis, Joseph; Germine, Laura; Wilmer, Jeremy B; Grosso, Mallory; Russo, Kathryn; Esterman, Michael

    2015-09-01

    Normal and abnormal differences in sustained visual attention have long been of interest to scientists, educators, and clinicians. Still lacking, however, is a clear understanding of how sustained visual attention varies across the broad sweep of the human life span. In the present study, we filled this gap in two ways. First, using an unprecedentedly large 10,430-person sample, we modeled age-related differences with substantially greater precision than have prior efforts. Second, using the recently developed gradual-onset continuous performance test (gradCPT), we parsed sustained-attention performance over the life span into its ability and strategy components. We found that after the age of 15 years, the strategy and ability trajectories saliently diverge. Strategy becomes monotonically more conservative with age, whereas ability peaks in the early 40s and is followed by a gradual decline in older adults. These observed life-span trajectories for sustained attention are distinct from results of other life-span studies focusing on fluid and crystallized intelligence.

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

    Science.gov (United States)

    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 ...

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

    Science.gov (United States)

    Orth, Ulrich; Maes, Jürgen; Schmitt, Manfred

    2015-01-01

    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…

  16. What about time? Examining chronological and subjective age and their relation to work motivation

    NARCIS (Netherlands)

    Akkermans, J.; Lange, A.H. de; Heijden, B.I.J.M. van der; Kooij, D.T.A.M.; Jansen, P.G.W.; Dikkers, J.S.E.

    2016-01-01

    PURPOSE - The aging workforce is becoming an increasingly important topic in today’s labor market. However, most scientific research and organizational policies focus on chronological age as the main determinant of successful aging. Based on life span developmental theories – primarily socioemotiona

  17. Implicit motor sequence learning and working memory performance changes across the adult life span

    Directory of Open Access Journals (Sweden)

    Sarah Nadine Meissner

    2016-04-01

    Full Text Available Although implicit motor sequence learning is rather well understood in young adults, effects of aging on this kind of learning are controversial. There is first evidence that working memory (WM might play a role in implicit motor sequence learning in young adults as well as in adults above the age of 65. However the knowledge about the development of these processes across the adult life span is rather limited. As the average age of our population continues to rise, a better understanding of age-related changes in motor sequence learning and potentially mediating cognitive processes takes on increasing significance. Therefore, we investigated aging effects on implicit motor sequence learning and WM. Sixty adults (18-71 years completed verbal and visuospatial n-back tasks and were trained on a serial reaction time task. Randomly varying trials served as control condition. To further assess consolidation indicated by off-line improvement and reduced susceptibility to interference, reaction times (RTs were determined 1 h after initial learning. Young and older but not middle-aged adults showed motor sequence learning. Nine out of 20 older adults (compared to one young/one middle-aged exhibited some evidence of sequence awareness. After 1 h, young and middle-aged adults showed off-line improvement. However, RT facilitation was not specific to sequence trials. Importantly, susceptibility to interference was reduced in young and older adults indicating the occurrence of consolidation. Although WM performance declined in older participants when load was high, it was not significantly related to sequence learning. The data reveal a decline in motor sequence learning in middle-aged but not in older adults. The use of explicit learning strategies in older adults might account for the latter result.

  18. Derived Trail Making Test indices: demographics and cognitive background variables across the adult life span.

    Science.gov (United States)

    Christidi, Foteini; Kararizou, Evangelia; Triantafyllou, Nikolaos; Anagnostouli, Maria; Zalonis, Ioannis

    2015-01-01

    We examined the contribution of demographics and cognitive background variables (processing speed, visuospatial skill, working memory, and interference control) on derived Trail Making Test (TMT) scores in a large sample of Greek healthy participants. We included 775 participants and administered the TMT (TMT-A and TMT-B) and the Wechsler Intelligence Adult Scale (WAIS). Direct (TMT-A & TMT-B time-to-completion) and derived [difference TMT-(B - A) & ratio TMT-(B/A)] scores were calculated. Demographics (age, age(2), education, and gender) and WAIS Full Intelligence Quotient significantly predicted the direct TMT-A (R(2) = 0.426) and TMT-B (R(2) = 0.593) scores and to a lesser extent, the derived TMT-(B - A) (R(2) = 0.343) and TMT-(B/A) (R(2) = 0.088) scores. In a subsample of 537 healthy participants who also completed the Stroop Neuropsychological Screening Test (SNST), demographics (age and education), WAIS Digit Symbol, Block Design, Arithmetic, and SNST accounted for 44.8% and 59.7% of the variance on TMT-A and TMT-B, and 32.5% and 9.6% of the variance on TMT-(B - A) and TMT-(B/A), respectively. We found minimal influence of Block Design and Arithmetic on TMT-(B - A) and an absence of significant influence of any cognitive variable on TMT-(B/A) score. Concluding, derived TMT scores are suggested as indices to detect impairment in cognitive flexibility across the adult life span, since they minimize the effect of demographics and other cognitive background variables.

  19. Missing doses in the life span study of Japanese atomic bomb survivors.

    Science.gov (United States)

    Richardson, David B; Wing, Steve; Cole, Stephen R

    2013-03-15

    The Life Span Study of atomic bomb survivors is an important source of risk estimates used to inform radiation protection and compensation. Interviews with survivors in the 1950s and 1960s provided information needed to estimate radiation doses for survivors proximal to ground zero. Because of a lack of interview or the complexity of shielding, doses are missing for 7,058 of the 68,119 proximal survivors. Recent analyses excluded people with missing doses, and despite the protracted collection of interview information necessary to estimate some survivors' doses, defined start of follow-up as October 1, 1950, for everyone. We describe the prevalence of missing doses and its association with mortality, distance from hypocenter, city, age, and sex. Missing doses were more common among Nagasaki residents than among Hiroshima residents (prevalence ratio = 2.05; 95% confidence interval: 1.96, 2.14), among people who were closer to ground zero than among those who were far from it, among people who were younger at enrollment than among those who were older, and among males than among females (prevalence ratio = 1.22; 95% confidence interval: 1.17, 1.28). Missing dose was associated with all-cancer and leukemia mortality, particularly during the first years of follow-up (all-cancer rate ratio = 2.16, 95% confidence interval: 1.51, 3.08; and leukemia rate ratio = 4.28, 95% confidence interval: 1.72, 10.67). Accounting for missing dose and late entry should reduce bias in estimated dose-mortality associations.

  20. Families enriched for exceptional longevity also have increased health span: Findings from the Long Life Family Study

    Directory of Open Access Journals (Sweden)

    Paola eSebastiani

    2013-09-01

    Full Text Available Hypothesizing that members of families enriched for longevity delay morbidity compared to population controls and approximate the health-span of centenarians, we compared the health spans of older generation subjects of the Long Life Family Study (LLFS to controls without family history of longevity and to centenarians of the New England Centenarian Study (NECS using Bayesian parametric survival analysis. We estimated hazard ratios, the ages at which specific percentiles of subjects had onsets of diseases, and the gain of years of disease-free survival in the different cohorts compared to referent controls. Compared to controls, LLFS subjects had lower hazards for cancer, cardiovascular disease, severe dementia, diabetes, hypertension, osteoporosis and stroke. The age at which 20% of the LLFS siblings and probands had one or more age-related diseases was approximately 10 years later than NECS controls. While female NECS controls generally delayed the onset of age-related diseases compared with males controls, these gender differences became much less in the older generation of the LLFS and disappeared amongst the centenarians of the NECS. The analyses demonstrate extended health-span in the older subjects of the LLFS and suggest that this aging cohort provides an important resource to discover genetic and environmental factors that promote prolonged health-span in addition to longer life-span.

  1. Blowup and life span bounds for a reaction-diffusion equation with a time-dependent generator

    Directory of Open Access Journals (Sweden)

    Aroldo Perez

    2008-01-01

    Full Text Available We consider the nonlinear equation $$ frac{partial}{partial t} u (t = k (t Delta _{alpha }u (t + u^{1+eta } (t,quad u(0,x=lambda varphi (x,; xin mathbb{R} ^{d}, $$ where $Delta _{alpha }:=-(-Delta^{alpha /2}$ denotes the fractional power of the Laplacian; $00$ are constants; $ varphi$ is bounded, continuous, nonnegative function that does not vanish identically; and $k$ is a locally integrable function. We prove that any combination of positive parameters $d,alpha, ho,eta$, obeying $0life span of the solution, and show that the life span satisfies $T_{lambdavarphi}sim lambda^{-alpha eta /(alpha -d ho eta }$ near $lambda=0$.

  2. The Development of Memory Efficiency and Value-Directed Remembering across the Life Span: A Cross-Sectional Study of Memory and Selectivity

    Science.gov (United States)

    Castel, Alan D.; Humphreys, Kathryn L.; Lee, Steve S.; Galvan, Adriana; Balota, David A.; McCabe, David P.

    2011-01-01

    Although attentional control and memory change considerably across the life span, no research has examined how the ability to strategically remember important information (i.e., value-directed remembering) changes from childhood to old age. The present study examined this in different age groups across the life span (N = 320, 5-96 years old). A…

  3. How Stable Is the Personal Past? Stability of Most Important Autobiographical Memories and Life Narratives Across Eight Years in a Life Span Sample.

    Science.gov (United States)

    Köber, Christin; Habermas, Tilmann

    2017-03-23

    Considering life stories as the most individual layer of personality (McAdams, 2013) implies that life stories, similar to personality traits, exhibit some stability throughout life. Although stability of personality traits has been extensively investigated, only little is known about the stability of life stories. We therefore tested the influence of age, of the proportion of normative age-graded life events, and of global text coherence on the stability of the most important memories and of brief entire life narratives as 2 representations of the life story. We also explored whether normative age-graded life events form more stable parts of life narratives. In a longitudinal life span study covering up to 3 measurements across 8 years and 6 age groups (N = 164) the stability of important memories and of entire life narratives was measured as the percentage of events and narrative segments which were repeated in later tellings. Stability increased between ages 8 and 24, leveling off in middle adulthood. Beyond age, stability of life narratives was also predicted by proportion of normative age-graded life events and by causal-motivational text coherence in younger participants. Memories of normative developmental and social transitional life events were more stable than other memories. Stability of segments of life narratives exceeded the stability of single most important memories. Findings are discussed in terms of cognitive, personality, and narrative psychology and point to research questions in each of these fields. (PsycINFO Database Record

  4. An approach to give prospective life-span of the copper/low-density-polyethylene nanocomposite intrauterine device.

    Science.gov (United States)

    Xia, Xianping; Tang, Ying; Xie, Changsheng; Wang, Yun; Cai, Shuizhou; Zhu, Changhong

    2011-07-01

    As a novel copper-containing intrauterine device (IUD), the prospective life-span of the copper/low-density-polyethylene (Cu/LDPE) nanocomposite IUD is very important for the future clinical use and should be given in advance. Here a novel approach, cupric ions accelerated release in diluted nitric acid solution and cupric ions concentration release in various volume of simulated uterine solution (SUS), is reported to verify the type of cupric ions release model of the cylindrical matrix-type nanocomposite IUD, and to obtain the minimal cupric ions release rate that need to ensure contraceptive efficacy and the thickness of copper particles exhausted layer of the cylindrical matrix-type nanocomposite IUD within two difficult immersion durations in experimental volume of SUS, respectively. Using these results, the prospective life-span of the cylindrical matrix-type nanocomposite IUD can be obtained. For instance, the prospective life-span of the novel γ-shape nanocomposite IUD with 25 wt% of copper nanoparticles and 2 mm of diameter and a total weight of 285 mg can be given in advance and it is about 5 years in the future clinical use.

  5. rBmαTX14 Increases the Life Span and Promotes the Locomotion of Caenorhabditis Elegans

    Science.gov (United States)

    Xu, Jie; Wan, Lu; Teng, Kaixuan; Xiang, Jin; Zhang, Rui; Huang, Zebo; Liu, Yongmei; Li, Wenhua; Liu, Xin

    2016-01-01

    The scorpion has been extensively used in various pharmacological profiles or as food supplies. The exploration of scorpion venom has been reported due to the presence of recombinant peptides. rBmαTX14 is an α-neurotoxin extracted from the venom gland of the East Asian scorpion Buthus martensii Karsch and can affect ion channel conductance. Here, we investigated the functions of rBmαTX14 using the Caenorhabditis elegans model. Using western blot analysis, rBmαTX14 was shown to be expressed both in the cytoplasm and inclusion bodies in the E.coli Rosetta (DE3) strain. Circular dichroism spectroscopy analysis demonstrated that purified rBmαTX14 retained its biological structures. Next, feeding nematodes with E.coli Rosetta (DE3) expressing rBmαTX14 caused extension of the life span and promoted the locomotion of the nematodes. In addition, we identified several genes that play various roles in the life span and locomotion of C. elegans through microarray analysis and quantitative real-time PCR. Furthermore, if the amino acid site H15 of rBmαTX14 was mutated, rBmαTX14 no longer promoted the C. elegans life span. In conclusion, the results not only demonstrated the functions and mechanism of rBmαTX14 in C. elegans, but also provided the new sight in the utility of recombinant peptides from scorpion venom. PMID:27611314

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

    Directory of Open Access Journals (Sweden)

    Gomez Fernando

    2012-12-01

    Full Text Available Abstract 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

  7. Life-Cycle Monitoring of Long-Span PSC Box Girder Bridges through Distributed Sensor Network: Strategies, Methods, and Applications

    Directory of Open Access Journals (Sweden)

    Zheheng Chen

    2015-01-01

    Full Text Available Structural health monitoring (SHM has attracted much attention in recent years, which enables early warnings of structural failure, condition assessments, and rational maintenance/repair strategies. In the context of bridges, many long-span steel bridges in China have been installed with the SHM systems; however, the applications of the SHM in prestressed concrete (PSC bridges are still rather limited. On the other hand, the PSC box girder bridges are extensively used in highway and railway systems and premature damage of these bridges is often reported, resulting in considerable maintenance and/or replacement costs. First, this paper presents a state-of-art review on the SHM of long-span PSC bridges. Monitoring strategies, methods, and previous applications for these bridges are summarized and discussed. In order to well capture the behavior of the bridge during its whole life and to maximize the use of sensors, a life-cycle monitoring strategy is proposed, in which the sensor layout is determined according to requirements for construction monitoring, completion test, and in-service monitoring. A case study is made on a three-span PSC box girder bridge in China. The system configuration, sensor layout, and data communications, and so forth, are presented. The up-to-date monitored structural responses are analyzed and compared with the design values.

  8. 论寿命学:1.成熟与成就%On the Life Span:1.Maturity and Achievements

    Institute of Scientific and Technical Information of China (English)

    李文彬; 张炳烈; 崔旭; 黄福南; 蔡竖平

    2001-01-01

    Based on the progress of life span study,it is concluded that a novel discipline called “life span science” is established.This conclusion comes out of following view points:1.The big succeses are raised in area of life span study,such as the genetic regulation of longevity as well as the promotive role of reactive oxygen species on aging;2.Theory about the determinant of life span derived from the evolutional and experimental study is accepted by more and more researchers;3.The principle and course of life span study is developed,especially,the artificial evolution model of life span is the main measure to disclose the mystery of longevity.The life span science will provide a theoritical tool to combat for longevity.%从寿命研究的历史轨迹和令人瞩目的成就着重论述了寿命学已经发展成熟,成为独立的学术体系并进一步从寿命进化的历程中探讨寿命形成的原因,指出氧的决定性作用,为提高生命质量,延长寿命提供科学依据。

  9. Hour glass half full or half empty? Future time perspective and preoccupation with negative events across the life span.

    Science.gov (United States)

    Strough, JoNell; Bruine de Bruin, Wändi; Parker, Andrew M; Lemaster, Philip; Pichayayothin, Nipat; Delaney, Rebecca

    2016-09-01

    According to socioemotional selectivity theory, older adults' emotional well-being stems from having a limited future time perspective that motivates them to maximize well-being in the "here and now." Presumably, then, older adults' time horizons are associated with emotional competencies that boost positive affect and dampen negative affect, but little research has addressed this. Using a U.S. adult life-span sample (N = 3,933; 18-93 years), we found that a 2-factor model of future time perspective (future opportunities; limited time) fit the data better than a 1-factor model. Through middle age, people perceived the life-span hourglass as half full-they focused more on future opportunities than limited time. Around Age 60, the balance changed to increasingly perceiving the life-span hourglass as half empty-they focused less on future opportunities and more on limited time, even after accounting for perceived health, self-reported decision-making ability, and retirement status. At all ages, women's time horizons focused more on future opportunities compared with men's, and men's focused more on limited time. Focusing on future opportunities was associated with reporting less preoccupation with negative events, whereas focusing on limited time was associated with reporting more preoccupation. Older adults reported less preoccupation with negative events, and this association was stronger after controlling for their perceptions of limited time and fewer future opportunities, suggesting that other pathways may explain older adults' reports of their ability to disengage from negative events. Insights gained and questions raised by measuring future time perspective as 2 dimensions are discussed. (PsycINFO Database Record

  10. Effect of Temperature on Imago Life Span, Fecundity and Reproduction Rate of Greenhouse Whitefly (T. vaporariorum W.

    Directory of Open Access Journals (Sweden)

    Pantelija Perić

    2006-01-01

    Full Text Available Imago life span, fecundity and survival rate of the different developmental stages and average abundance of female offspring of greenhouse whitefly (Trialeurodes vaporariorum were studied at three constant (18, 22 and 27°C and one alternating (18/7°C temperature.Temperature highs are inversely proportionate to imago life span. Temperature increase from 18/7°C to 27°C decreased the whitefly life span 3.3-fold. Under 18°C and 22°C, whitefly laid eggs most abundantly (147 and 126, respectively, while fecundity decreased under lower and higher temperatures. Half the offspring of the investigated whitefly laboratory strain (49.5% were males, which resulted in lower values of reproduction and growth rates of the whitefly strain.Optimum development of greenhouse whitefly was achieved at 18°C, which is evident from a maximum number of eggs laid and highest average number of potential and actual female offspring (68.2 and 58.3, respectively, compared to the other investigated temperatures.The consequence of a 50.8-day long true generation time is evident from the low values of growth capacity (0.074 and intrinsic rate of increase (0.080. With temperature increasing to 22°C and 27°C, the period of whitefly oviposition showed a tendency to decrease further on. Higher temperatures reduced the total abundance of eggs laid and, consequently, the abundance of potential and actual female offspring, but increased growth rate.

  11. Social relationships and physiological determinants of longevity across the human life span.

    Science.gov (United States)

    Yang, Yang Claire; Boen, Courtney; Gerken, Karen; Li, Ting; Schorpp, Kristen; Harris, Kathleen Mullan

    2016-01-19

    Two decades of research indicate causal associations between social relationships and mortality, but important questions remain as to how social relationships affect health, when effects emerge, and how long they last. Drawing on data from four nationally representative longitudinal samples of the US population, we implemented an innovative life course design to assess the prospective association of both structural and functional dimensions of social relationships (social integration, social support, and social strain) with objectively measured biomarkers of physical health (C-reactive protein, systolic and diastolic blood pressure, waist circumference, and body mass index) within each life stage, including adolescence and young, middle, and late adulthood, and compare such associations across life stages. We found that a higher degree of social integration was associated with lower risk of physiological dysregulation in a dose-response manner in both early and later life. Conversely, lack of social connections was associated with vastly elevated risk in specific life stages. For example, social isolation increased the risk of inflammation by the same magnitude as physical inactivity in adolescence, and the effect of social isolation on hypertension exceeded that of clinical risk factors such as diabetes in old age. Analyses of multiple dimensions of social relationships within multiple samples across the life course produced consistent and robust associations with health. Physiological impacts of structural and functional dimensions of social relationships emerge uniquely in adolescence and midlife and persist into old age.

  12. The specificity of childhood adversities and negative life events across the life span to anxiety and depressive disorders

    NARCIS (Netherlands)

    Spinhoven, Philip; Elzinga, Bernet M.; Hovens, Jacqueline G. F. M.; Roelofs, Karin; Zitman, Frans G.; van Oppen, Patricia; Penninx, Brenda W. J. H.

    2010-01-01

    Background: Although several studies have shown that life adversities play an important role in the etiology and maintenance of both depressive and anxiety disorders, little is known about the relative specificity of several types of life adversities to different forms of depressive and anxiety diso

  13. Bile Acid Look-Alike Controls Life Span in C. elegans

    NARCIS (Netherlands)

    Groen, Albert K.; Kuipers, Folkert

    2013-01-01

    Extensive transcriptional networks maintain sterol homeostasis across species, underscoring the importance of sterol balance for healthy life. Magner et al. (2013) now show that, in C. elegans, the nuclear receptor NHR-8 is key in regulation of cholesterol balance and production of dafachronic acid,

  14. Metabolic Features Across the Female Life Span in Women with PCOS.

    Science.gov (United States)

    Sir-Petermann, Teresa; Echiburú, Bárbara; Crisosto, Nicolás; Maliqueo, Manuel; Bravo, Francisco Pérez

    2016-01-01

    Polycystic ovary syndrome (PCOS) is a highly prevalent endocrine metabolic disorder and is presently considered a family pathology. It is associated with obesity, insulin resistance and metabolic syndrome. Racial, ethnic and environmental factors may be important in determining the clinical manifestations of this syndrome. Polycystic ovary syndrome is an exclusion diagnosis and, therefore, should be distinguished from the physiological changes typical for the age and from other hyperandrogenic disorders. Early diagnosis is important since this syndrome is associated with reproductive, oncologic and metabolic risks. Interestingly, the clinical features of this disorder may change throughout the lifespan of a PCOS woman, starting from adolescence to postmenopausal age. During the first decades of life the main features are in the reproductive area, while later in life metabolic abnormalities are more evident. While the assessment of insulin resistance is not part of the diagnosis of PCOS, it has been demonstrated that this metabolic component appears early in life and persists over time. Moreover during puberty and pregnancy, insulin resistance is exacerbated. Pregnancy represents an important stage, as the offspring of these patients may be reprogrammed and inherit some of the metabolic and reproductive features of their mothers. In the present review, we will focus on several metabolic aspects of the PCOS condition at different stages of life in a Chilean population.

  15. Sparing of the extraocular muscles in mdx mice with absent or reduced utrophin expression: A life span analysis.

    Science.gov (United States)

    McDonald, Abby A; Hebert, Sadie L; McLoon, Linda K

    2015-11-01

    Sparing of the extraocular muscles in muscular dystrophy is controversial. To address the potential role of utrophin in this sparing, mdx:utrophin(+/-) and mdx:utrophin(-/-) mice were examined for changes in myofiber size, central nucleation, and Pax7-positive and MyoD-positive cell density at intervals over their life span. Known to be spared in the mdx mouse, and contrary to previous reports, the extraocular muscles from both the mdx:utrophin(+/-) and mdx:utrophin(-/-) mice were also morphologically spared. In the mdx:utrophin(+/)(-) mice, which have a normal life span compared to the mdx:utrophin(-/-) mice, the myofibers were larger at 3 and 12 months than the wild type age-matched eye muscles. While there was a significant increase in central nucleation in the extraocular muscles from all mdx:utrophin(+/)(-) mice, the levels were still very low compared to age-matched limb skeletal muscles. Pax7- and MyoD-positive myogenic precursor cell populations were retained and were similar to age-matched wild type controls. These results support the hypothesis that utrophin is not involved in extraocular muscle sparing in these genotypes. In addition, it appears that these muscles retain the myogenic precursors that would allow them to maintain their regenerative capacity and normal morphology over a lifetime even in these more severe models of muscular dystrophy.

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

    Energy Technology Data Exchange (ETDEWEB)

    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); Shin, Ki-Hyuk [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); Park, No-Hee [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

    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.

  17. Assimilation of endogenous nicotinamide riboside is essential for calorie restriction-mediated life span extension in Saccharomyces cerevisiae.

    Science.gov (United States)

    Lu, Shu-Ping; Kato, Michiko; Lin, Su-Ju

    2009-06-19

    NAD(+) (nicotinamide adenine dinucleotide) is an essential cofactor involved in various biological processes including calorie restriction-mediated life span extension. Administration of nicotinamide riboside (NmR) has been shown to ameliorate deficiencies related to aberrant NAD(+) metabolism in both yeast and mammalian cells. However, the biological role of endogenous NmR remains unclear. Here we demonstrate that salvaging endogenous NmR is an integral part of NAD(+) metabolism. A balanced NmR salvage cycle is essential for calorie restriction-induced life span extension and stress resistance in yeast. Our results also suggest that partitioning of the pyridine nucleotide flux between the classical salvage cycle and the NmR salvage branch might be modulated by the NAD(+)-dependent Sir2 deacetylase. Furthermore, two novel deamidation steps leading to nicotinic acid mononucleotide and nicotinic acid riboside production are also uncovered that further underscore the complexity and flexibility of NAD(+) metabolism. In addition, utilization of extracellular nicotinamide mononucleotide requires prior conversion to NmR mediated by a periplasmic phosphatase Pho5. Conversion to NmR may thus represent a strategy for the transport and assimilation of large nonpermeable NAD(+) precursors. Together, our studies provide a molecular basis for how NAD(+) homeostasis factors confer metabolic flexibility.

  18. Mechanisms of age-related decline in memory search across the adult life span.

    Science.gov (United States)

    Hills, Thomas T; Mata, Rui; Wilke, Andreas; Samanez-Larkin, Gregory R

    2013-12-01

    Three alternative mechanisms for age-related decline in memory search have been proposed, which result from either reduced processing speed (global slowing hypothesis), overpersistence on categories (cluster-switching hypothesis), or the inability to maintain focus on local cues related to a decline in working memory (cue-maintenance hypothesis). We investigated these 3 hypotheses by formally modeling the semantic recall patterns of 185 adults between 27 to 99 years of age in the animal fluency task (Thurstone, 1938). The results indicate that people switch between global frequency-based retrieval cues and local item-based retrieval cues to navigate their semantic memory. Contrary to the global slowing hypothesis that predicts no qualitative differences in dynamic search processes and the cluster-switching hypothesis that predicts reduced switching between retrieval cues, the results indicate that as people age, they tend to switch more often between local and global cues per item recalled, supporting the cue-maintenance hypothesis. Additional support for the cue-maintenance hypothesis is provided by a negative correlation between switching and digit span scores and between switching and total items recalled, which suggests that cognitive control may be involved in cue maintenance and the effective search of memory. Overall, the results are consistent with age-related decline in memory search being a consequence of reduced cognitive control, consistent with models suggesting that working memory is related to goal perseveration and the ability to inhibit distracting information.

  19. Visualizing Life Zone Boundary Sensitivities Across Climate Models and Temporal Spans

    Energy Technology Data Exchange (ETDEWEB)

    Sisneros, Roberto R [ORNL; Huang, Jian [University of Tennessee, Knoxville (UTK); Ostrouchov, George [ORNL; Hoffman, Forrest M [ORNL

    2011-01-01

    Life zones are a convenient and quantifiable method for delineating areas with similar plant and animal communities based on bioclimatic conditions. Such ecoregionalization techniques have proved useful for defining habitats and for studying how these habitats may shift due to environmental change. The ecological impacts of climate change are of particular interest. Here we show that visualizations of the geographic projection of life zones may be applied to the investigation of potential ecological impacts of climate change using the results of global climate model simulations. Using a multi-factor classification scheme, we show how life zones change over time based on quantitative model results into the next century. Using two straightforward metrics, we identify regions of high sensitivity to climate changes from two global climate simulations under two different greenhouse gas emissions scenarios. Finally, we identify how preferred human habitats may shift under these scenarios. We apply visualization methods developed for the purpose of displaying multivariate relationships within data, especially for situations that involve a large number of concurrent relationships. Our method is based on the concept of multivariate classification, and is implemented directly in VisIt, a production quality visualization package.

  20. Review of the literature and suggestions for the design of rodent survival studies for the identification of compounds that increase health and life span.

    Science.gov (United States)

    Spindler, Stephen Richard

    2012-02-01

    Much of the literature describing the search for agents that increase the life span of rodents was found to suffer from confounds. One-hundred-six studies, absent 20 contradictory melatonin studies, of compounds or combinations of compounds were reviewed. Only six studies reported both life span extension and food consumption data, thereby excluding the potential effects of caloric restriction. Six other studies reported life span extension without a change in body weight. However, weight can be an unreliable surrogate measure of caloric consumption. Twenty studies reported that food consumption or weight was unchanged, but it was unclear whether these data were anecdotal or systematic. Twenty-nine reported extended life span likely due to induced caloric restriction. Thirty-six studies reported no effect on life span, and three a decrease. The remaining studies suffer from more serious confounds. Though still widely cited, studies showing life span extension using short-lived or "enfeebled" rodents have not been shown to predict longevity effects in long-lived animals. We suggest improvements in experimental design that will enhance the reliability of the rodent life span literature. First, animals should receive measured quantities of food and its consumption monitored, preferably daily, and reported. Weights should be measured regularly and reported. Second, a genetically heterogeneous, long-lived rodent should be utilized. Third, chemically defined diets should be used. Fourth, a positive control (e.g., a calorically restricted group) is highly desirable. Fifth, drug dosages should be chosen based on surrogate endpoints or accepted cross-species scaling factors. These procedures should improve the reliability of the scientific literature and accelerate the identification of longevity and health span-enhancing agents.

  1. Minocycline increases the life span and motor activity and decreases lipid peroxidation in manganese treated Drosophila melanogaster.

    Science.gov (United States)

    Bonilla, E; Contreras, R; Medina-Leendertz, S; Mora, M; Villalobos, V; Bravo, Y

    2012-03-29

    The objective of this study was to investigate the effect of Minocycline in the life span, motor activity, and lipid peroxidation of Drosophila melanogaster treated with manganese. Two days after emerging from the pupa male wild-type D. melanogaster were fed for 13 days with corn media containing 15 mM manganese. Then, they were divided in six groups of 300 flies each: group (a) remained treated with manganese (Mn group); group (b) began treatment with Minocycline (0.05 mM) (Mn-Minocycline group); group (c) received no additional treatment (Mn-no treatment group); group (d) simultaneously fed with manganese and Minocycline (Mn+Minocycline group). Additionally, a control (group e) with no treatment and another group (f) fed only with Minocycline after emerging from the pupa were added. All the manganese treated flies (group a) were dead on the 25th day. The life span in group f (101.66±1.33 days, mean S.E.M.) and of group b (97.00±3.46 days) were similar, but in both cases it was significantly higher than in group e (68.33±1.76 days), group c (67.05±2.30 days) and in those of group d (37.33±0.88). Manganese (groups a and d) decreased motor activity in D. melanogaster. In the Minocycline fed flies (groups b and f) a higher motor activity was detected. In Mn-Minocycline and Mn+Minocycline treated flies a significant decrease of MDA levels was detected when compared to the Minocycline group indicating that Minocycline and Mn appear to have a synergistic effect. In conclusion, Minocycline increased the life span and motor activity and decreased MDA formation of manganese treated D. melanogaster, probably by an inhibition of the production of reactive oxygen species. Manganese also exerted an antioxidant effect as shown by the significant decrease of MDA levels when compared to control flies.

  2. Promoting sexuality across the life span for individuals with intellectual and developmental disabilities.

    Science.gov (United States)

    Ailey, Sarah H; Marks, Beth A; Crisp, Cheryl; Hahn, Joan Earle

    2003-06-01

    Sexuality is a human right that is important to all individuals regardless of age, gender, orientation, or developmental level. Sexuality is closely related to a person's self-concept and self-esteem. Individuals with I/DD have a right to sexuality and sexual expression. Nevertheless, persons with I/DD have historically been denied this right, and many structural and attitudinal barriers exist to their healthy sexuality. Paradigms in sexuality education have shifted toward recognizing sexuality as a human right, a major life resource, and an integral part of one's makeup. To broadly address the development of healthy sexuality for individuals with I/DD, the issue needs to be normalized, not ignored or avoided; which means involving parents, staff, and professionals. Working with parents to overcome parental overprotection and social isolation is critical. Parents can provide opportunities for their sons and daughters to network and form meaningful personal relationships, with peers including encouraging association with peers outside of school or work hours.

  3. Long-term aerobic exercise is associated with greater muscle strength throughout the life span.

    Science.gov (United States)

    Crane, Justin D; Macneil, Lauren G; Tarnopolsky, Mark A

    2013-06-01

    Aging is associated with a progressive decline in muscle strength, muscle mass, and aerobic capacity, which reduces mobility and impairs quality of life in elderly adults. Exercise is commonly employed to improve muscle function in individuals of all ages; however, chronic aerobic exercise is believed to largely impact cardiovascular function and oxidative metabolism, with minimal effects on muscle mass and strength. To study the effects of long-term aerobic exercise on muscle strength, we recruited 74 sedentary (SED) or highly aerobically active (ACT) men and women from within three distinct age groups (young: 20-39 years, middle: 40-64 years, and older: 65-86 years) and tested their aerobic capacity, isometric grip and knee extensor strength, and dynamic 1 repetition maximum knee extension. As expected, ACT subjects had greater maximal oxygen uptake and peak aerobic power output compared with SED subjects (p aerobic exercise appears to attenuate age-related reductions in muscle strength in addition to its cardiorespiratory and metabolic benefits.

  4. Conceptualization of the Life-Span Development Theory: Relevance for Sexual and Reproductive Health in Ghana

    Directory of Open Access Journals (Sweden)

    Baba Musah Iddrisu

    2013-06-01

    Full Text Available Sexual and reproductive health issues continue to generate concerns in contemporarysociety because it is essential to individuals, couples and families, as well as the social andeconomic development of communities and nations. The concept of sexual andreproductive health (SRH provides a comprehensive and integrated approach to healthneeds related to sexuality and reproduction when viewed from the lens of lifespandevelopment theory. It is a public health concern, human rights issue and is indispensableto the attainment of the Millennium Development Goals because three out of the eightgoals are directly related to SRH, while the others have a close relationship with health.The 1994 International Conference on Population and Development in Cairo provided animpetus for program planners, family planning researchers, service providers, policymakers and other stakeholders to recognize the importance of SRH internationally.Nonetheless, the global situation depicts clear inequities between developed anddeveloping regions. Also, women bear the major share of the burden of sexual andreproductive ill health compared to men. It is essential to close these regional and gendergaps since SRH is vital to our quality of life, as other major aspects of health. This paper,which is an exploration of the literature, highlights the (a importance of SRH across thehuman lifespan, (b determinants of SRH in Ghana, and (c challenges associated withSRH issues in Ghana. Also, implications of SRH for public health education, policy,practice and research are discussed.

  5. Language Development across the Life Span: A Neuropsychological/Neuroimaging Perspective

    Directory of Open Access Journals (Sweden)

    Mónica Rosselli

    2014-01-01

    Full Text Available Language development has been correlated with specific changes in brain development. The aim of this paper is to analyze the linguistic-brain associations that occur from birth through senescence. Findings from the neuropsychological and neuroimaging literature are reviewed, and the relationship of language changes observable in human development and the corresponding brain maturation processes across age groups are examined. Two major dimensions of language development are highlighted: naming (considered a major measure of lexical knowledge and verbal fluency (regarded as a major measure of language production ability. Developmental changes in the brain lateralization of language are discussed, emphasizing that in early life there is an increase in functional brain asymmetry for language, but that this asymmetry changes over time, and that changes in the volume of gray and white matter are age-sensitive. The effects of certain specific variables, such as gender, level of education, and bilingualism are also analyzed. General conclusions are presented and directions for future research are suggested.

  6. Brain growth across the life span in autism: age-specific changes in anatomical pathology.

    Science.gov (United States)

    Courchesne, Eric; Campbell, Kathleen; Solso, Stephanie

    2011-03-22

    Autism is marked by overgrowth of the brain at the earliest ages but not at older ages when decreases in structural volumes and neuron numbers are observed instead. This has led to the theory of age-specific anatomic abnormalities in autism. Here we report age-related changes in brain size in autistic and typical subjects from 12 months to 50 years of age based on analyses of 586 longitudinal and cross-sectional MRI scans. This dataset is several times larger than the largest autism study to date. Results demonstrate early brain overgrowth during infancy and the toddler years in autistic boys and girls, followed by an accelerated rate of decline in size and perhaps degeneration from adolescence to late middle age in this disorder. We theorize that underlying these age-specific changes in anatomic abnormalities in autism, there may also be age-specific changes in gene expression, molecular, synaptic, cellular, and circuit abnormalities. A peak age for detecting and studying the earliest fundamental biological underpinnings of autism is prenatal life and the first three postnatal years. Studies of the older autistic brain may not address original causes but are essential to discovering how best to help the older aging autistic person. Lastly, the theory of age-specific anatomic abnormalities in autism has broad implications for a wide range of work on the disorder including the design, validation, and interpretation of animal model, lymphocyte gene expression, brain gene expression, and genotype/CNV-anatomic phenotype studies.

  7. Statistical modeling of biomedical corpora: mining the Caenorhabditis Genetic Center Bibliography for genes related to life span

    Directory of Open Access Journals (Sweden)

    Jordan MI

    2006-05-01

    Full Text Available Abstract Background The statistical modeling of biomedical corpora could yield integrated, coarse-to-fine views of biological phenomena that complement discoveries made from analysis of molecular sequence and profiling data. Here, the potential of such modeling is demonstrated by examining the 5,225 free-text items in the Caenorhabditis Genetic Center (CGC Bibliography using techniques from statistical information retrieval. Items in the CGC biomedical text corpus were modeled using the Latent Dirichlet Allocation (LDA model. LDA is a hierarchical Bayesian model which represents a document as a random mixture over latent topics; each topic is characterized by a distribution over words. Results An LDA model estimated from CGC items had better predictive performance than two standard models (unigram and mixture of unigrams trained using the same data. To illustrate the practical utility of LDA models of biomedical corpora, a trained CGC LDA model was used for a retrospective study of nematode genes known to be associated with life span modification. Corpus-, document-, and word-level LDA parameters were combined with terms from the Gene Ontology to enhance the explanatory value of the CGC LDA model, and to suggest additional candidates for age-related genes. A novel, pairwise document similarity measure based on the posterior distribution on the topic simplex was formulated and used to search the CGC database for "homologs" of a "query" document discussing the life span-modifying clk-2 gene. Inspection of these document homologs enabled and facilitated the production of hypotheses about the function and role of clk-2. Conclusion Like other graphical models for genetic, genomic and other types of biological data, LDA provides a method for extracting unanticipated insights and generating predictions amenable to subsequent experimental validation.

  8. Human adipose tissue derived pericytes increase life span in Utrn (tm1Ked) Dmd (mdx) /J mice.

    Science.gov (United States)

    Valadares, M C; Gomes, J P; Castello, G; Assoni, A; Pellati, M; Bueno, C; Corselli, M; Silva, H; Bartolini, P; Vainzof, M; Margarido, P F; Baracat, E; Péault, B; Zatz, M

    2014-12-01

    Duchenne muscular dystrophy (DMD) is still an untreatable lethal X-linked disorder, which affects 1 in 3500 male births. It is caused by the absence of muscle dystrophin due to mutations in the dystrophin gene. The potential regenerative capacity as well as immune privileged properties of mesenchymal Stem Cells (MSC) has been under investigation for many years in an attempt to treat DMD. One of the questions to be addressed is whether stem cells from distinct sources have comparable clinical effects when injected in murine or canine muscular dystrophy animal models. Many studies comparing different stem cells from various sources were reported but these cells were obtained from different donors and thus with different genetic backgrounds. Here we investigated whether human pericytes obtained from 4 different tissues (muscle, adipose tissue, fallopian tube and endometrium) from the same donor have a similar clinical impact when injected in double mutant Utrn (tm1Ked) Dmd (mdx) /J mice, a clinically relevant model for DMD. After a weekly regimen of intraperitoneal injections of 10(6) cells per 8 weeks we evaluated the motor ability as well as the life span of the treated mice as compared to controls. Our experiment showed that only adipose tissue derived pericytes are able to increase significantly (39 days on average) the life span of affected mice. Microarray analysis showed an inhibition of the interferon pathway by adipose derived pericytes. Our results suggest that the clinical benefit associated with intraperitoneal injections of these adult stem cells is related to immune modulation rather than tissue regeneration.

  9. Carbon dynamics in aboveground biomass of co-dominant plant species: related rather to leaf life span than to species

    Science.gov (United States)

    Ostler, Ulrike; Schleip, Inga; Lattanzi, Fernando A.; Schnyder, Hans

    2016-04-01

    This study investigates the role of individual organisms in whole ecosystem carbon (C) fluxes. It is currently unknown if different plant community members share the same or different kinetics of C pools in aboveground biomass, thereby adding (or not) variability to the first steps in ecosystem C cycling. We assessed the residence times in metabolic and non-metabolic (or structural) C pools and the allocation pattern of assimilated C in aboveground plant parts of four co-existing, co-dominant species from different functional groups in a temperate grassland community. For this purpose continuous, 14-16 day long 13CO2/12CO2-labeling experiments were performed in Sept. 2006, May 2007 and Sept. 2007, and the tracer kinetics were analysed with compartmental modeling. In all experimental periods, the species shared vastly similar residence times in metabolic C (5-8 d). In contrast, the residence times in non-metabolic C ranged from 20 to 58 d (except one outlier) and the fraction of fixed C allocated to the non-metabolic pool from 7 to 45%. These variations in non-metabolic C kinetics were not systematically associated with species or experimental periods, but exhibited close relationships with (independent estimates of) leaf life span, particularly in the grasses. This adds new meaning to leaf life span as a functional trait in the leaf and plant economics spectrum and its implication for C cycle studies in grassland and also forest systems. As the four co-dominant species accounted for ~80% of total community shoot biomass, we should also expect that the observed similarities in pool kinetics and allocation will scale up to similar relationships at the community level.

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

    Science.gov (United States)

    Koumoula, A

    2012-06-01

    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

  11. Environmental effects on the expression of life span and aging: an extreme contrast between wild and captive cohorts of Telostylinus angusticollis (Diptera: Neriidae).

    Science.gov (United States)

    Kawasaki, Noriyoshi; Brassil, Chad E; Brooks, Robert C; Bonduriansky, Russell

    2008-09-01

    Most research on life span and aging has been based on captive populations of short-lived animals; however, we know very little about the expression of these traits in wild populations of such organisms. Because life span and aging are major components of fitness, the extent to which the results of many evolutionary studies in the laboratory can be generalized to natural settings depends on the degree to which the expression of life span and aging differ in natural environments versus laboratory environments and whether such environmental effects interact with phenotypic variation. We investigated life span and aging in Telostylinus angusticollis in the wild while simultaneously estimating these parameters under a range of conditions in a laboratory stock that was recently established from the same wild population. We found that males live less than one-fifth as long and age at least twice as rapidly in the wild as do their captive counterparts. In contrast, we found no evidence of aging in wild females. These striking sex-specific differences between captive and wild flies support the emerging view that environment exerts a profound influence on the expression of life span and aging. These findings have important implications for evolutionary gerontology and, more generally, for the interpretation of fitness estimates in captive populations.

  12. Environmental enrichment improves age-related immune system impairment: long-term exposure since adulthood increases life span in mice.

    Science.gov (United States)

    Arranz, Lorena; De Castro, Nuria M; Baeza, Isabel; Maté, Ianire; Viveros, Maria Paz; De la Fuente, Mónica

    2010-08-01

    Age-related changes in immunity have been shown to highly influence morbidity and mortality. The aim of the present work was to study the effects of environmental enrichment (EE) (8-16 weeks) on several functions and oxidative stress parameters of peritoneal leukocytes, previously described as health and longevity markers, in mice at different ages, namely adult (44 +/- 4 weeks), old (69 +/- 4 weeks), and very old (92 +/- 4 weeks). Mortality rates were monitored in control and enriched animals, and effects on survival of long-term exposure to EE until natural death were determined. The results showed that exposure to EE was efficient in improving the function (i.e., macrophage chemotaxis and phagocytosis, lymphocyte chemotaxis and proliferation, natural killer cell activity, interleukin-2 and tumor necrosis factor-alpha levels) and decreasing the oxidative-inflammatory stress (i.e., lowered oxidized glutathione content, xanthine oxidase activity, expression of Toll-like receptors 2 and 4 on CD4 and CD8 cells, and increased reduced glutathione and glutathione peroxidase and catalase activities) of immune cells. These positive effects of EE were especially remarkable in animals at older ages. Importantly, long-term exposure to EE from adult age and until natural death stands out as a useful strategy to extend longevity. Thus, the present work confirms the importance of maintaining active mental and/or physical activity aiming to improve quality of life in terms of immunity, and demonstrates that this active life must be initiated at early stages of the aging process and preserved until death to improve life span.

  13. How much should we weigh for a long and healthy life span?The need to reconcile caloric restriction versus longevity with body mass index versus mortality data.

    Directory of Open Access Journals (Sweden)

    Antonello eLorenzini

    2014-07-01

    Full Text Available Total caloric restriction (CR without malnutrition is a well-established experimental approach to extend life span in laboratory animals. Although CR in humans is capable of shifting several endocrinological parameters it is not clear where the minimum inflection point of the U shaped curve linking body mass index (BMI with all-cause mortality lies. The exact trend of this curve, when used for planning preventive strategies for public health is of extreme importance. Normal BMI ranges from 18.5 to 24.9; many epidemiological studies show an inverse relationship between mortality and BMI inside the normal BMI range. Other studies show that the lowest mortality in the entire range of BMI is obtained in the overweight range (25 to 29.9. Reconciling the extension of life span in laboratory animals by experimental CR with the BMI-mortality curve of human epidemiology is not trivial. In fact, one interpretation is that the CR data are identifying a known: excess fat is deleterious for health; although a second interpretation may be that: additional leanness from a normal body weight may add health and life span delaying the process of aging. This short review hope to start a discussion aimed at finding the widest consensus on which weight range should be consider the healthiest for our species, contributing in this way to the picture of what is the correct life style for a long and healthy life span.

  14. Inventions in nanotechnological field provide increased strength and life span of the metal, composite and polymer, metallopolymer structures

    Directory of Open Access Journals (Sweden)

    VLASOV Vladimir Alexeevich

    2014-02-01

    Full Text Available The invention «The method of dispersion of nanoparticles in epoxy resin (RU 2500706» refers to nanotechnological field and it can be applied in different areas of machine industry, transport, construction, power engineering to increase strength and life span of the structures made of metal, composite and polymer, metallopolymer materials, for glue and glue and mechanical joints in different structure elements as well as for compositions which strengthen the stress concentration zones (in the form of holes, cutouts, fillet, thickness differentials in structures, to reform defects, microcracks and other damages occurring in production and performance of structures, to eliminate and encapsulate the gaps in holes and meeting-points of bolted and riveted joints. The invention «The method to produce nanosuspension for manufacturing polymer nanocomposite (RU 2500695» refers to the area of production of polymer nanocomposites based on reactiveplastic binder for space, aircraft, construction and other types of structures (glass-fiber plastic, carbon reinforced plastic, organic plastic, etc.. The method includes preparation of nanosuspension by introducing carbon nanotubes into reactiveplastic binder under ultrasonic treatment with intensity cavity zone 15–25 kW/m². The method makes it possible to optimize the degree of dispersion of carbon nanotubes in binder and to shorten production time of nanocomposites possessing increased strength due to even distribution of nanoparticles in nanocomposite.

  15. Liver-specific γ-glutamyl carboxylase-deficient mice display bleeding diathesis and short life span.

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    Kotaro Azuma

    Full Text Available 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 γ-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(Δliver/Δliver mice. In contrast to conventional Ggcx knockout mice, Ggcx(Δliver/Δliver mice had very low activity of Ggcx in the liver and survived several weeks after birth. Furthermore, compared with heterozygous mice (Ggcx(+/Δliver , Ggcx(Δliver/Δliver mice had shorter life spans. Ggcx(Δliver/Δliver 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.

  16. The Lignan Pinoresinol Induces Nuclear Translocation of DAF-16 in Caenorhabditis elegans but has No Effect on Life Span.

    Science.gov (United States)

    Koch, Karoline; Büchter, Christian; Havermann, Susannah; Wätjen, Wim

    2015-06-01

    The lignan pinoresinol is a constituent of flaxseed, sesame seeds and olive oil. Because of different molecular effects reported for this compound, e.g. antioxidative activity, pinoresinol is suggested to cause positive effects on humans. Because experimental data are limited, we have analysed the effects of the lignan on the nematode Caenorhabditis elegans: in spite of a strong antioxidative capacity detected in an in vitro assay, no antioxidative effects were detectable in vivo. In analogy to this result, no modulation of the sensitivity against thermal stress was detectable. However, incubation with pinoresinol caused an enhanced nuclear accumulation of the transcription factor DAF-16 (insulin/IGF-like signalling pathway). Using a strain with an enhanced oxidative stress level (mev-1 mutant), we clearly see an increase in stress resistance caused by this lignan, but no change in reactive oxygen species. Furthermore, we investigated the effects of pinoresinol on the life span of the nematode, but no modulation was found, neither in wild-type nor in mev-1 mutant nematodes. These results suggest that pinoresinol may exert pharmacologically interesting effects via modulation of the insulin-like signalling pathway in C. elegans as well as in other species like mammals due to the evolutionary conservation of this signalling pathway.

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

    Institute of Scientific and Technical Information of China (English)

    LI Jing; PANG Shaojun; LIU Feng; SHAN Tifeng; GAO Suqin

    2013-01-01

    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,Saccharinajaponica 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℃,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.

  18. Estrogens maintain bone mass by regulating expression of genes controlling function and life span in mature osteoclasts.

    Science.gov (United States)

    Imai, Yuuki; Youn, Ming-Young; Kondoh, Shino; Nakamura, Takashi; Kouzmenko, Alexander; Matsumoto, Takahiro; Takada, Ichiro; Takaoka, Kunio; Kato, Shigeaki

    2009-09-01

    Estrogens play a key role in regulation of bone mass and strength by controlling activity of bone-forming osteoblasts and bone-resorbing osteoclasts. Cellular effects of estrogens are mediated predominantly by the action of estrogen receptor alpha (ERalpha). In earlier studies, ablation of the ERalpha gene in mice did not result in osteoporotic phenotypes due to systemic endocrine disturbance and compensatory effects of elevated levels of testosterone. Despite the relatively well-established effects in osteoblasts, little is known about the direct action of estrogen in osteoclasts. Development in the last decade of more sophisticated genetic manipulation approaches opened new possibilities to explore cell-specific roles of nuclear receptors in bone tissue. Recently, we have generated osteoclast-specific ERalpha gene knockout mice and shown that in vivo estrogens directly regulate the life span of mature osteoclasts by inducing the expression of pro-apoptotic Fas ligand (FasL). Inhibitory effects of estrogens on osteoclast function were further studied in vitro. We observed sufficiently detectable ERalpha expression in osteoclasts differentiating from primary bone marrow cells or RAW264 cells, although levels of ERalpha were decreasing during progression of the differentiation into mature osteoclasts. Treatment with estrogens led to reduction in expression of osteoclast-specific genes controlling bone resorption activity. However, estrogens did not affect the size of multinucleated osteoclasts or number of nuclei in a mature osteoclast. In conclusion, in osteoclasts, estrogens function to inhibit bone resorption activity and vitality rather than differentiation.

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

    Directory of Open Access Journals (Sweden)

    Koella Jacob C

    2009-03-01

    Full Text Available Abstract 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.

  20. Physical Attractiveness and Self-Esteem in Middle Childhood: Do Recent Life-Span Developmental Texts Perpetuate or Challenge Gender Stereotypes?

    Science.gov (United States)

    Hensley, Beth H.

    This document reports on an investigation focusing on how the content of introductory college psychology texts' content related to physical attractiveness and self-esteem. The primary objective of this study was to review how recently published life-span developmental texts present physical development in middle childhood as related to traditional…

  1. Developmental and age-specific effects of selection on divergent virgin life span on fat content and starvation resistance in Drosophila melanogaster

    NARCIS (Netherlands)

    Vermeulen, Cornelis; Van de Zande, Louis; Bijlsma, R.

    2006-01-01

    Investigations into the genetic basis of longevity variation have shown life span to be positively correlated with starvation resistance and negatively with female fecundity, both of which rely on lipid content. To assess the firmness of this relation, we assayed correlated responses in age-specific

  2. dSir2 in the Adult Fat Body, but Not in Muscles, Regulates Life Span in a Diet-Dependent Manner

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    Kushal Kr. Banerjee

    2012-12-01

    Full Text Available Sir2, an evolutionarily conserved NAD+-dependent deacetylase, has been implicated as a key factor in mediating organismal life span. However, recent contradictory findings have brought into question the role of Sir2 and its orthologs in regulating organismal longevity. In this study, we report that Drosophila Sir2 (dSir2 in the adult fat body regulates longevity in a diet-dependent manner. We used inducible Gal4 drivers to knock down and overexpress dSir2 in a tissue-specific manner. A diet-dependent life span phenotype of dSir2 perturbations (both knockdown and overexpression in the fat body, but not muscles, negates the effects of background genetic mutations. In addition to providing clarity to the field, our study contrasts the ability of dSir2 in two metabolic tissues to affect longevity. We also show that dSir2 knockdown abrogates fat-body dFOXO-dependent life span extension. This report highlights the importance of the interplay between genetic factors and dietary inputs in determining organismal life spans.

  3. Protein methionine content and MDA-lysine adducts are inversely related to maximum life span in the heart of mammals.

    Science.gov (United States)

    Ruiz, Maria Cristina; Ayala, Victoria; Portero-Otín, Manel; Requena, Jesús R; Barja, Gustavo; Pamplona, Reinald

    2005-10-01

    Aging affects all organisms and its basic mechanisms are expected to be conserved across species. Oxidation of proteins has been proposed to be one of the basic mechanisms linking oxygen radicals with the basic aging process. If oxidative damage to proteins is involved in aging, long-lived animals (which age slowly) should show lower levels of markers of this kind of damage than short-lived ones. However, this possibility has not been investigated yet. In this study, steady-state levels of markers of different kinds of protein damage--oxidation (glutamic and aminoadipic semialdehydes), mixed glyco- and lipoxidation (carboxymethyl- and carboxyethyllysine), lipoxidation (malondialdehydelysine) and amino acid composition--were measured in the heart of eight mammalian species ranging in maximum life span (MLSP) from 3.5 to 46 years. Oxidation markers were directly correlated with MLSP across species. Mixed glyco- and lipoxidation markers did not correlate with MLSP. However, the lipoxidation marker malondialdehydelysine was inversely correlated with MLSP (r2=0.85; P<0.001). The amino acid compositional analysis revealed that methionine is the only amino acid strongly correlated MLSP and that such correlation is negative (r2=0.93; P<0.001). This trait may contribute to lower steady-state levels of oxidized methionine residues in cellular proteins. These results reinforce the notion that high longevity in homeothermic vertebrates is achieved in part by constitutively decreasing the sensitivity of both tissue proteins and lipids to oxidative damage. This is obtained by modifying the constituent structural components of proteins and lipids, selecting those less sensitive to oxidative modifications.

  4. Effects of PPP1R1B (DARPP-32 Polymorphism on Feedback-related Brain Potentials across the Life Span

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    Dorothea eHämmerer

    2013-03-01

    Full Text Available Maximizing gains during probabilistic reinforcement learning requires the updating of choice–outcome expectations at the time when the feedback about a specific choice or action is given. Extant theories and evidence suggest that dopaminergic modulation plays a crucial role in reinforcement learning and the updating of choice–outcome expectations. Furthermore, recently a positive component of the event-related potential (ERP about 200 msec (P2 after feedback has been suggested to reflect such updating. The efficacy of dopaminergic modulation changes across the life span. However, to date investigations of age-related differences in feedback-related P2 during reinforcement learning are still scarce. The present study thus aims to investigate whether individual differences in the feedback-related P2 would be associated with polymorphic variations in a dopamine relevant gene PPP1R1B (also known as DARPP-32 and whether the genetic effect may differ between age groups. We observed larger P2 amplitudes in individuals carrying the genotype associated with higher dopamine receptor efficacy, i.e., A allele homozygotes of a single nucleotide polymorphism (rs907094 of the PPP1R1B gene. Moreover, this effect was more pronounced in children and older adults in comparison to adolescents and younger adults. Together, our findings indicate that polymorphic variations in a dopamine relevant gene are associated with individual differences in brain-evoked potentials of outcome updating and hint at the possibility that genotype effects on neurocognitive phenotypes may vary as a function of brain maturation and aging.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1985-05-01

    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.

  6. Body size, growth and life span: implications for the polewards range shift of Octopus tetricus in south-eastern Australia.

    Directory of Open Access Journals (Sweden)

    Jorge E Ramos

    Full Text Available 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.

  7. Body size, growth and life span: implications for the polewards range shift of Octopus tetricus in south-eastern Australia.

    Science.gov (United States)

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

    2014-01-01

    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.

  8. Positive regulation of DNA double strand break repair activity during differentiation of long life span cells: the example of adipogenesis.

    Directory of Open Access Journals (Sweden)

    Aline Meulle

    Full Text Available Little information is available on the ability of terminally differentiated cells to efficiently repair DNA double strand breaks (DSBs, and one might reasonably speculate that efficient DNA repair of these threatening DNA lesions, is needed in cells of long life span with no or limited regeneration from precursor. Few tissues are available besides neurons that allow the study of DNA DSBs repair activity in very long-lived cells. Adipocytes represent a suitable model since it is generally admitted that there is a very slow turnover of adipocytes in adult. Using both Pulse Field Gel Electrophoresis (PFGE and the disappearance of the phosphorylated form of the histone variant H2AX, we demonstrated that the ability to repair DSBs is increased during adipocyte differentiation using the murine pre-adipocyte cell line, 3T3F442A. In mammalian cells, DSBs are mainly repaired by the non-homologous end-joining pathway (NHEJ that relies on the DNA dependent protein kinase (DNA-PK activity. During the first 24 h following the commitment into adipogenesis, we show an increase in the expression and activity of the catalytic sub-unit of the DNA-PK complex, DNA-PKcs. The increased in DNA DSBs repair activity observed in adipocytes was due to the increase in DNA-PK activity as shown by the use of DNA-PK inhibitor or sub-clones of 3T3F442A deficient in DNA-PKcs using long term RNA interference. Interestingly, the up-regulation of DNA-PK does not regulate the differentiation program itself. Finally, similar positive regulation of DNA-PKcs expression and activity was observed during differentiation of primary culture of pre-adipocytes isolated from human sub-cutaneous adipose tissue. Our results show that DNA DSBs repair activity is up regulated during the early commitment into adipogenesis due to an up-regulation of DNA-PK expression and activity. In opposition to the general view that DNA DSBs repair is decreased during differentiation, our results demonstrate

  9. Acacetin 7-O-α-l-rhamnopyranosyl (1-2) β-D-xylopyranoside Elicits Life-span Extension and Stress Resistance in Caenorhabditis elegans.

    Science.gov (United States)

    Asthana, Jyotsna; Yadav, Deepti; Pant, Aakanksha; Yadav, A K; Gupta, M M; Pandey, Rakesh

    2016-09-01

    The advancements in the field of gerontology have unraveled the signaling pathways that regulate life span, suggesting that it might be feasible to modulate aging. To this end, we isolated a novel phytomolecule Acacetin 7-O-α-l-rhamnopyranosyl (1-2) β-D-xylopyranoside (ARX) from Premna integrifolia and evaluated its antiaging effects in Caenorhabditis elegans The spectral data analysis revealed the occurrence of a new compound ARX. Out of the three tested pharmacological doses of ARX, viz. 5, 25, and 50 µM, the 25-µM dose was able to extend life span in C. elegans by more than 39%. The present study suggests that ARX affects bacterial metabolism, which in turn leads to dietary restriction (DR)-like effects in the worms. The effect of ARX on worms with mutations (mev-1, eat-2, sir-2.1, skn-1, daf-16, and hsf-1) indicates that ARX-mediated life-span extension involves mechanisms associated with DR and maintenance of cellular redox homeostasis. This study is the first time report on longevity-promoting activity of ARX in C. elegans mediated by stress and DR-regulating genes. This novel phytomolecule can contribute in designing therapeutics for managing aging and age-related diseases.

  10. Antioxidant capacity of "Mexican arnica" Heterotheca inuloides Cass natural products and some derivatives: their anti-inflammatory evaluation and effect on C. elegans life span.

    Science.gov (United States)

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

    2015-01-01

    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 (1)O2, 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.

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

    Directory of Open Access Journals (Sweden)

    José Luis Rodríguez-Chávez

    2015-01-01

    Full Text Available 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.

  12. Being Labeled as Gifted, Self-Appraisal, and Psychological Well-Being: A Life Span Developmental Perspective.

    Science.gov (United States)

    Holahan, Carole K.; Holahan, Charles J.

    1999-01-01

    Examines the relation of being labeled as intellectually gifted to a mid-life appraisal of having lived up to one's abilities and to psychological well-being at age 80. Learning at a younger age of membership in a study of intellectual giftedness was related to less likelihood of believing that one has lived up to one's intellectual abilities at…

  13. Life span variations in 128 successive generations of D. melanogaster. I. Evidence that the phenomenon exists and analysis of the variations mode.

    Science.gov (United States)

    Izmaylov, D M; Obukhova, L K

    2003-05-01

    Survival of Drosophila melanogaster was estimated in 128 successive generations for 5 years. The resultant 116 samples (58 for females and 58 for males) containing series of individual values of life span (LS; 50-90 values in each series) were analyzed. Each of 58 pairs of samples belonged to a definite generation in a continuous succession where every next generation was an offspring of the preceding one. In total, 10180 Drosophila flies (5100 females and 5080 males) were studied. The mean life span (MLS) was found to be considerably heterogeneous in the series of generations: in many pairs of consecutive generations, MLSs significantly differed within two errors of the mean (Psuccessive generations of D. melanogaster. Highly significant (Psuccessive generations of the same population, with the proportions of individuals with low and high LSs remaining about the same irrespective of the MLS. It was demonstrated with the use of mathematical simulation that the MLS changes in successive generations may be regarded as an oscillatory process and described as a sum of several (three to five) harmonic components. The calculated determination coefficients were high (93.51 and 88.93% for females and males, respectively). This indicates that the mathematical model used for simulation adequately described the observed variations in MLS. The results are discussed in terms of population gerontology and the problem of geroprotector effectiveness.

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

    Directory of Open Access Journals (Sweden)

    Hector Flavio Ortega-Arellano

    2013-01-01

    Full Text Available 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; χ² 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.

  15. Phototoxic effect of UVR on wild type, ebony and yellow mutants of Drosophila melanogaster: Life Span, fertility, courtship and biochemical aspects

    Institute of Scientific and Technical Information of China (English)

    WANG ZhePeng; LIU RuiFang; WANG AnRu; DU LiLi; DENG XueMei

    2008-01-01

    Melanin plays an important role in protecting organisms from ultraviolet radiation (UVR). Therefore, it is possible that differently colored strains can show different sensitivities to UVR. In the present work, life span, fertility and courtship behavior of wild type (w), ebony (e) and yellow (y) strains of Drosophila melanogaster were studied to evaluate their sensitivity to ultraviolet (UV). Because a range of photo-toxic effects of UVR are mediated through generation of free radicals, levels of free radicals, lipid per-oxide (malondialdehyde, MDA) and superoxide dismutase (SOD) activity of three strains were examined to indicate their antioxidant defending ability and oxidative status. It was shown that w always had the highest lifespan and fertility not only in the control but also in UV-exposed groups. Moreover, lifespan and fertility of e were significantly higher (P0.05). MDA levels were increased in the UV dose-dependent manner (P=0.0495). In con-clusion, our results suggested that UVB can decrease life span and fertility of flies and do harm to courtship, which may be due to oxidative damage to flies tissues (e.g. central nervous system) induced by free radicals, w had the highest tolerance to UVR, which may be ascribed to its advantage of survival under the natural condition and at high level of SOD activity. Then differences of pigment between e and y in absorbing UV, shielding against UV and scavenging free radicals produced by UVR should be responsible for their different sensitivity to UVR.

  16. Effects of salinity on egg and fecal pellet production, development and survival, adult sex ratio and total life span in the calanoid copepod, Acartia tonsa: a laboratory study

    Science.gov (United States)

    Shayegan, Majid; Esmaeili Fereidouni, Abolghasem; Agh, Naser; Jani Khalili, Khosrow

    2016-07-01

    The effects of salinity on the copepod, Acartia tonsa in terms of daily egg production rate (EPR), hatching success, fecal pellet production rate (FPR), naupliar development time and survival, sex ratio, and total life span were determined in laboratory conditions through three experiments. In experiment 1, EPR, hatching success, and FPR of individual females were monitored at salinities of 13, 20, 35 and 45 during short-periods (seven consecutive days). Results show EPR was affected by salinity with the highest outputs recorded at 20 and 35, respectively, which were considerably higher than those at 13 and 45. Mean FPR was also higher in 35 and 20. In experiment 2, the same parameters were evaluated over total life span of females (long-term study). The best EPR and FPR were observed in 35, which was statistically higher than at 13 and 20. In experiment 3, survival rates of early nauplii until adult stage were lowest at a salinity of 13. The development time increased with increasing of salinity. Female percentage clearly decreased with increasing salinity. Higher female percentages (56.7% and 52.2%, respectively) were significantly observed at two salinities of 13 and 20 compared to that at 35 (25%). Total longevity of females was not affected by salinity increment. Based on our results, for mass culture we recommend that a salinity of 35 be adopted due to higher reproductive performances, better feeding, and faster development of A. tonsa.

  17. Karyotypic instability and centrosome aberrations in the progeny of finite life-span human mammary epithelial cells exposed to sparsely or densely ionizing radiation.

    Science.gov (United States)

    Sudo, Hiroko; Garbe, James; Stampfer, Martha R; Barcellos-Hoff, Mary Helen; Kronenberg, Amy

    2008-07-01

    The human breast is sensitive to radiation carcinogenesis, and genomic instability occurs early in breast cancer development. This study tests the hypothesis that ionizing radiation elicits genomic instability in finite life-span human mammary epithelial cells (HMEC) and asks whether densely ionizing radiation is a more potent inducer of instability. HMEC in a non-proliferative state were exposed to X rays or 1 GeV/nucleon iron ions followed by delayed plating. Karyotypic instability and centrosome aberrations were monitored in expanded clonal isolates. Severe karyotypic instability was common in the progeny of cells that survived X-ray or iron-ion exposure. There was a lower dose threshold for severe karyotypic instability after iron-ion exposure. More than 90% of X-irradiated colonies and >60% of iron-ion-irradiated colonies showed supernumerary centrosomes at levels above the 95% upper confidence limit of the mean for unirradiated clones. A dose response was observed for centrosome aberrations for each radiation type. There was a statistically significant association between the incidence of karyotypic instability and supernumerary centrosomes for iron-ion-exposed colonies and a weaker association for X-irradiated colonies. Thus genomic instability occurs frequently in finite life-span HMEC exposed to sparsely or densely ionizing radiation and may contribute to radiation-induced breast cancer.

  18. L-carnitine suppresses the onset of neuromuscular degeneration and increases the life span of mice with familial amyotrophic lateral sclerosis.

    Science.gov (United States)

    Kira, Yukimi; Nishikawa, Manabu; Ochi, Akemi; Sato, Eisuke; Inoue, Masayasu

    2006-01-27

    Amyotrophic lateral sclerosis (ALS) is a fatal disease caused by progressive degeneration of motor neurons in the spinal cord and motor cortex. Although the etiology of ALS remains unknown, a mutation of the gene encoding Cu,Zn-superoxide dismutase (SOD1) has been reported in 20% of familial cases of ALS (FALS). Transgenic mice that overexpress a mutated human SOD1 exhibit a phenotype and pathology similar to those observed in patients with FALS. Mitochondrial abnormality has been reported in patients with ALS and in animal models of FALS. We recently reported that L-carnitine, an essential cofactor for the beta-oxidation of long-chain fatty acids, effectively inhibits various types of mitochondrial injury and apoptosis both in vitro and in vivo. The present study demonstrates that oral administration of L-carnitine prior to disease onset significantly delayed the onset of signs of disease (log-rank P=0.0008), delayed deterioration of motor activity, and extended life span (log-rank P=0.0001) in transgenic mice carrying a human SOD1 gene with a G93A mutation (Tg). More importantly, subcutaneous injection of L-carnitine increased the life span of Tg mice (46% increase in male, 60% increase in female) even when given after the appearance of signs of disease.

  19. Polyphenolic drug composition based on benzenepolycarboxylic acids (BP-C3) increases life span and inhibits spontaneous tumorigenesis in female SHR mice

    Science.gov (United States)

    Anisimov, Vladimir N.; Popovich, Irina G.; Zabezhinski, Mark A.; Yurova, Maria N.; Tyndyk, Margarita L.; Anikin, Ivan V.; Egormin, Peter A.; Baldueva, Irina A.; Fedoros, Elena I.; Pigarev, Sergey E.; Panchenko, Andrey V.

    2016-01-01

    Effects of long-term application of novel polyphenolic composition BP-C3, containing polyphenolic benzenepolycarboxylic acids, vitamins and minerals on some biomarkers of aging, life span and spontaneous tumorigenesis has been studied in female SHR mice. Administration of BP-C3 with drinking water (0.005%) did not exert any toxic effect (did not have effect on general condition of animals, weight dynamics and consumption of food), postponed age-related switch-off of estrous function, caused slight reduction of body temperature. An increased survival was observed in mice treated with BP-C3 (p=0.00164, log rank test). BP-C3 increased mean lifespan – by 8.4%, lifespan of the last 10% of animals – by 12.4%, and life span of tumor-free mice – by 11.6%. A tendency in ability of BP-C3 to inhibit development of spontaneous tumors in mice was detected, though it did not reach the level of statistical significance (p=0.166, log rank test). The number of malignant mammary tumors was 1.5 times less and total number of tumors of various localizations was 1.6 times less in BP-C3 treated animals. Multiple tumors were registered in 8% of mice in the control group and no cases – in BP-C3 treated group. Thus, BP-C3 demonstrated some anti-carcinogenic and a pronounced geroprotective activity. PMID:27574962

  20. The histone demethylase Dmel\\Kdm4A controls genes required for life span and male-specific sex determination in Drosophila.

    Science.gov (United States)

    Lorbeck, Meridith T; Singh, Neetu; Zervos, Ashley; Dhatta, Madhusmita; Lapchenko, Maria; Yang, Chen; Elefant, Felice

    2010-01-15

    Histone methylation plays an important role in regulating chromatin-mediated gene control and epigenetic-based memory systems that direct cell fate. Enzymes termed histone demethylases directly remove the methyl marks from histones, thus contributing to a dynamically regulated histone methylated genome; however, the biological functions of these newly identified enzymes remain unclear. The JMJD2A-D family belongs to the JmjC domain-containing family of histone demethylases (JHDMs). Here, we report the cloning and functional characterization of the Drosophila HDM gene Dmel\\Kdm4A that is a homolog of the human JMJD2 family. We show that homologs for three human JHDM families, JHDM1, JHDM2, and JMJD2, are present in Drosophila and that each is expressed during the Drosophila lifecycle. Disruption of Dmel\\Kdm4A results in a reduction of the male life span and a male-specific wing extension/twitching phenotype that occurs in response to other males and is reminiscent of an inter-male courtship phenotype involving the courtship song. Remarkably, certain genes associated with each of these phenotypes are significantly downregulated in response to Dmel\\Kdm4A loss, most notably the longevity associated Hsp22 gene and the male sex-determination fruitless gene. Our results have implications for the role of the epigenetic regulator Dmel\\Kdm4A in the control of genes involved in life span and male-specific sex determination in the fly.

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

    Science.gov (United States)

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

    2013-01-01

    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; χ2 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

  2. Life span extension by resveratrol, rapamycin, and metformin: The promise of dietary restriction mimetics for an healthy aging.

    Science.gov (United States)

    Mouchiroud, Laurent; Molin, Laurent; Dallière, Nicolas; Solari, Florence

    2010-01-01

    Life expectancy at the turn of the 20th century was 46 years on average worldwide and it is around 65 years today. The correlative increase in age-associated diseases incidence has a profound public health impact and is an important matter of concern for our societies. Aging is a complex, heterogeneous, and multifactorial phenomenon, which is the consequence of multiple interactions between genes and environment. In this review, we survey animals models that have been of great help for both investigating mechanism of aging and identifying molecules, which slow down the onset of age-related diseases. Resveratrol (RSV) is one of those. We will report evidences supporting RSV as a molecule that acts by mimicking the beneficial effects of dietary restriction, and may share common downstream targets with rapamycin and metformin. Although those molecules do not reveal all the secrets of the fountain of youth, they may help us maintaining the quality of life in the old age.

  3. Sex effects on life span and senescence in the wild when dates of birth and death are unknown.

    Science.gov (United States)

    Zajitschek, Felix; Brassil, Chad E; Bonduriansky, Russell; Brooks, Robert C

    2009-06-01

    Males and females allocate and schedule reproductive effort in very different ways. Because the timing and amount of reproductive effort influence survival and thus the optimization of life histories, mortality and senescence are predicted to be sex specific. However, age-specific mortality rates of wild animals are often difficult to quantify in natural populations. Studies that report mortality rates from natural populations are, therefore, almost entirely confined to long-lived, easy-to-track species such as large mammals and birds. Here, we employ a novel approach using capture-mark-recapture data from a wild population of black field crickets (Teleogryllus commodus) to test for sex differences in demographic aging. In this species, the age of captured adults cannot be readily determined, and animals cannot be reliably captured or observed every night, resulting in demographic data on individuals whose dates of birth and death are unknown. We implement a recently developed life-table analysis for wild-caught individuals of unknown age, in combination with a well-established capture-mark-recapture methodology that models probabilistic dates of death. This unified analytical framework makes it possible to test for aging in wild, hard-to-track animals. Using these methods to fit Gompertz models of age-specific mortality, we show that male crickets have higher mortality rates throughout life than female crickets. Furthermore, males and females both exhibit increasing mortality rates with age, indicating senescence, but the rate of senescence is not sex specific. Thus, observed sex differences in longevity are probably due to differences in baseline mortality rather than aging. Our findings illustrate the complexity of the relationships between sex, background mortality, and senescence rate in wild populations, showing that the elevated mortality rate of males need not be coupled with an elevated rate of aging.

  4. 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.

    Science.gov (United States)

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

    2009-01-01

    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.

  5. The Tölz Temporal Topography Study: mapping the visual field across the life span. Part I: the topography of light detection and temporal-information processing.

    Science.gov (United States)

    Poggel, Dorothe A; Treutwein, Bernhard; Calmanti, Claudia; Strasburger, Hans

    2012-08-01

    Temporal performance parameters vary across the visual field. Their topographical distributions relative to each other and relative to basic visual performance measures and their relative change over the life span are unknown. Our goal was to characterize the topography and age-related change of temporal performance. We acquired visual field maps in 95 healthy participants (age: 10-90 years): perimetric thresholds, double-pulse resolution (DPR), reaction times (RTs), and letter contrast thresholds. DPR and perimetric thresholds increased with eccentricity and age; the periphery showed a more pronounced age-related increase than the center. RT increased only slightly and uniformly with eccentricity. It remained almost constant up to the age of 60, a marked change occurring only above 80. Overall, age was a poor predictor of functionality. Performance decline could be explained only in part by the aging of the retina and optic media. In Part II, we therefore examine higher visual and cognitive functions.

  6. Differential effects of IGF-1 deficiency during the life span on structural and biomechanical properties in the tibia of aged mice.

    Science.gov (United States)

    Ashpole, Nicole M; Herron, Jacquelyn C; Estep, Patrick N; Logan, Sreemathi; Hodges, Erik L; Yabluchanskiy, Andriy; Humphrey, Mary Beth; Sonntag, William E

    2016-04-01

    Advanced aging is associated with the loss of structural and biomechanical properties in bones, which increases the risk for bone fracture. Aging is also associated with reductions in circulating levels of the anabolic signaling hormone, insulin-like growth factor (IGF)-1. While the role of IGF-1 in bone development has been well characterized, the impact of the age-related loss of IGF-1 on bone aging remains controversial. Here, we describe the effects of reducing IGF-1 at multiple time points in the mouse life span--early in postnatal development, early adulthood, or late adulthood on tibia bone aging in both male and female igf (f/f) mice. Bone structure was analyzed at 27 months of age using microCT. We find that age-related reductions in cortical bone fraction, cortical thickness, and tissue mineral density were more pronounced when IGF-1 was reduced early in life and not in late adulthood. Three-point bone bending assays revealed that IGF-1 deficiency early in life resulted in reduced maximum force, maximum bending moment, and bone stiffness in aged males and females. The effects of IGF-1 on bone aging are microenvironment specific, as early-life loss of IGF-1 resulted in decreased cortical bone structure and strength along the diaphysis while significantly increasing trabecular bone fraction and trabecular number at the proximal metaphysis. The increases in trabecular bone were limited to males, as early-life loss of IGF-1 did not alter bone fraction or number in females. Together, our data suggest that the age-related loss of IGF-1 influences tibia bone aging in a sex-specific, microenvironment-specific, and time-dependent manner.

  7. Changes in gas exchange characteristics during the life span of giant sequoia: Implications for response to current and future concentrations of atmospheric ozone

    Energy Technology Data Exchange (ETDEWEB)

    Grulke, N.E.; Miller, P.R. (USDA Forest Service, Riverside, CA (United States))

    Native stands of giant sequoia are being exposed to relatively high concentrations of atmospheric ozone produced in urban and agricultural areas upwind. The expected change in environmental conditions over the next 100 y is likely to be unprecendented in the life span (ca 2,500 y) of giant sequoia. Changes in the physiological responses of three age classes of giant sequoia (current year, 12 y and 25 y) to different concentrations of ozone were determined, and age-related differences in sensitivity to pollutants were assessed by examining physiological changes (gas exchange, water use efficiency) across the life span of giant sequoia. The CO[sub 2] exchange rate (CER) was greater in current year (12.1 [mu]mol CO[sub 2]/m[sup 2]s) and 2 year old seedlings (4.8 [mu]mol CO[sub 2]/m[sup 2]s) than in all older trees (average of 3.0 [mu]mol CO[sub 2]/m[sup 2]s). Dark respiration was highest for current year seedlings and was increased twofold in symptotic individuals exposed to elevated ozone concentrations. Stomatal conductance was greater in current-year and 2 year old seedlings (335 and 200 mmol H[sub 2]O/m[sup 2]s), respectively, than in all older trees (50 mmol H[sub 2]O/m[sup 2]s), indicating that the ozone concentration in substomatol cavities is higher in young seedlings than in older trees. Significant changes in water use efficiency occurred in trees between ages 5 and 20 years. It is concluded that giant sequoia seedlings are sensitive to atmospheric ozone until they are ca 5 y old. Low conductance, high water use efficiency, and compact mesophyll all contribute to a natural ozone tolerance, or defense, or both, in foliage of older trees. 11 refs., 1 fig., 1 tab.

  8. Character strengths and well-being across the life span: data from a representative sample of German-speaking adults living in Switzerland.

    Science.gov (United States)

    Martínez-Martí, María L; Ruch, Willibald

    2014-01-01

    Character strengths are positive, morally valued traits of personality. This study aims at assessing the relationship between character strengths and subjective well-being (i.e., life satisfaction, positive and negative affect) in a representative sample of German-speaking adults living in Switzerland (N = 945). We further test whether this relationship is consistent at different stages in life. Results showed that hope, zest, love, social intelligence and perseverance yielded the highest positive correlations with life satisfaction. Hope, zest, humor, gratitude and love presented the highest positive correlations with positive affect. Hope, humor, zest, honesty, and open-mindedness had the highest negative correlations with negative affect. When examining the relationship between strengths and well-being across age groups, in general, hope, zest and humor consistently yielded the highest correlations with well-being. Additionally, in the 27-36 years group, strengths that promote commitment and affiliation (i.e., kindness and honesty) were among the first five positions in the ranking of the relationship between strengths and well-being. In the 37-46 years group, in addition to hope, zest and humor, strengths that promote the maintenance of areas such as family and work (i.e., love, leadership) were among the first five positions in the ranking. Finally, in the 47-57 years group, in addition to hope, zest and humor, strengths that facilitate integration and a vital involvement with the environment (i.e., gratitude, love of learning) were among the first five positions in the ranking. This study partially supports previous findings with less representative samples on the association between character strengths and well-being, and sheds light on the relative importance of some strengths over others for well-being across the life span.

  9. Character strengths and well-being across the life span: Data from a representative sample of German-speaking adults living in Switzerland

    Directory of Open Access Journals (Sweden)

    María Luisa eMartínez Martí

    2014-11-01

    Full Text Available Character strengths are positive, morally valued traits of personality. This study aims at assessing the relationship between character strengths and subjective well-being (i.e., life satisfaction, positive and negative affect in a representative sample of German-speaking adults living in Switzerland (N = 945. We further test whether this relationship is consistent at different stages in life. Results showed that hope, zest, love, social intelligence and perseverance yielded the highest positive correlations with life satisfaction. Hope, zest, humor, gratitude and love presented the highest positive correlations with positive affect. Hope, humor, zest, honesty, and open-mindedness had the highest negative correlations with negative affect. When examining the relationship between strengths and well-being across age groups, in general, hope, zest and humor consistently yielded the highest correlations with well-being. Additionally, in the 27-36 years group, strengths that promote commitment and affiliation (i.e., kindness and honesty were among the first five positions in the ranking of the relationship between strengths and well-being. In the 37-46 years group, in addition to hope, zest and humor, strengths that promote the maintenance of areas such as family and work (i.e., love, leadership were among the first five positions in the ranking. Finally, in the 47-57 years group, in addition to hope, zest and humor, strengths that facilitate integration and a vital involvement with the environment (i.e., gratitude, love of learning were among the first five positions in the ranking. This study partially supports previous findings with less representative samples on the association between character strengths and well-being, and sheds light on the relative importance of some strengths over others for well-being across the life span.

  10. Chronological History of Federal Fleet Actions and Mandates (Brochure)

    Energy Technology Data Exchange (ETDEWEB)

    2011-04-01

    This chronological history of Federal fleet actions and mandates provides a year-by-year timeline of the acts, amendments, executive orders, and other regulations that affect Federal fleets. The fleet actions and mandates included in the timeline span from 1988 to 2009.

  11. Inbred strains of brine shrimp derived from Artemia franciscana: lineage, RAPD analysis, life span, reproductive traits and mode, adaptation, and tolerance to salinity changes.

    Science.gov (United States)

    Nambu, Fumiko; Tanaka, Shin; Nambu, Ziro

    2007-02-01

    Inbred strains of the brine shrimp were developed from dry dormant cysts of wild-type Artemia franciscana produced in the Great Salt Lake, U.S.A. The established strains were named GSL2, 4, and 7. They were raised in 2% natural sea salt solution at 28 degrees C under a long-day condition, and fed on food sold for Artemia. Ovoviviparous offspring (free-swimming nauplii) in each brood derived from full sib (sister x brother) matings were used for succeeding generations. The ordinal number of the filial generation increased at a rate of ten generations per year. The number was over 60, and the lineage was recorded. Random amplified polymorphic DNA (RAPD) analyses of the inbred strains revealed the uniqueness, homogeneity, and genetic similarity among them. Their life span, the time required to become sexually mature, brood size, mode of reproduction, and adaptation and tolerance to salinity changes were investigated. The inbred strains usually released free-swimming nauplii rather than spawning encysted gastrulae (dormant cysts). On the other hand, the opposite results were obtained from wild-type Artemia under the same conditions. Both adults and nauplii of the inbred strains appeared to be less adaptive and less tolerant to salinity changes compared to those of the wild type. The established inbred strains should provide a wider and deeper scope for Artemia biology in particular, and the life sciences in general.

  12. Suicide: Across the Life Span.

    Science.gov (United States)

    Ramirez, Jeffery

    2016-06-01

    Suicide remains a major public health issue. There have been more than 40,000 deaths by suicide in 2014. Understanding both the neuroscience and psychological development is key for nursing care so adequate interventions and treatment strategies are developed when working with people thinking about suicide. It is critical to assess and recognize risk and protective factors to ensure patient safety. The older adult, children, and adolescent populations remain vulnerable to suicide. A discussion regarding the psychiatric, psychosocial, and treatment considerations for these populations is included. An overview of communication, suicide assessment, and safety planning is discussed.

  13. Life span in online communities

    Science.gov (United States)

    Grabowski, A.; Kosiński, R. A.

    2010-12-01

    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.

  14. Phototoxic effect of UVR on wild type, ebony and yellow mutants of Drosophila melanogaster: Life Span, fertility, courtship and biochemical aspects

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Melanin plays an important role in protecting organisms from ultraviolet radiation (UVR). Therefore, it is possible that differently colored strains can show different sensitivities to UVR. In the present work, life span, fertility and courtship behavior of wild type (w), ebony (e) and yellow (y) strains of Drosophila melanogaster were studied to evaluate their sensitivity to ultraviolet (UV). Because a range of photo- toxic effects of UVR are mediated through generation of free radicals, levels of free radicals, lipid per- oxide (malondialdehyde, MDA) and superoxide dismutase (SOD) activity of three strains were examined to indicate their antioxidant defending ability and oxidative status. It was shown that w always had the highest lifespan and fertility not only in the control but also in UV-exposed groups. Moreover, lifespan and fertility of e were significantly higher (P<0.0001) than those of y in the UV-exposed groups, but not for the control. On the other hand, UV exposure had an adverse effect on courtship of flies. Stronger electron paramagnetic resonance (EPR) signals could be detected in w, e and y exposed to 5 min UV. And there were more significant changes of EPR signals in y than in w and e. UVR had no significant (P=0.1782) effect on the SOD activities. After pooling data from the control and UV-exposed groups, we found that w had a significantly (P<0.05) higher level of SOD activity, but e and y were nearly at the same levels (P>0.05). MDA levels were increased in the UV dose-dependent manner (P=0.0495). In con- clusion, our results suggested that UVR can decrease life span and fertility of flies and do harm to courtship, which may be due to oxidative damage to flies tissues (e.g. central nervous system) induced by free radicals. w had the highest tolerance to UVR, which may be ascribed to its advantage of survival under the natural condition and at high level of SOD activity. Then differences of pigment between e and y in absorbing UV, shielding

  15. Changes in gas exchange characteristics during the life span of giant sequoia: implications for response to current and future concentrations of atmospheric ozone.

    Science.gov (United States)

    Grulke, N. E.; Miller, P. R.

    1994-01-01

    Native stands of giant sequoia (Sequoiadendron giganteum Bucholz) are being exposed to relatively high concentrations of atmospheric ozone produced in urban and agricultural areas upwind. The expected change in environmental conditions over the next 100 years is likely to be unprecedented in the life span (about 2,500 years) of giant sequoia. We determined changes in physiological responses of three age classes of giant sequoia (current-year, 12-, and 125-year-old) to differing concentrations of ozone, and assessed age-related differences in sensitivity to pollutants by examining physiological changes (gas exchange, water use efficiency) across the life span of giant sequoia (current-year, 2-, 5-, 20-, 125-, and > 2,000-year-old trees). The CO(2) exchange rate (CER) was greater in current-year (12.1 micro mol CO(2) m(-2) s(-1)) and 2-year-old seedlings (4.8 micro mol CO(2) m(-2) s(-1)) than in all older trees (3.0 micro mol CO(2) m(-2) s(-1), averaged across the four older age classes). Dark respiration was highest for current-year seedlings (-6.5 +/- 0.7 micro mol CO(2) m(-2) s(-1)) and was increased twofold in symptomatic individuals exposed to elevated ozone concentrations. Stomatal conductance (g(s)) was greater in current-year (355 mmol H(2)O m(-2) s(-1)) and 2-year-old seedlings (200 mmol H(2)O m(-2) s(-1)) than in all older trees (50 mmol H(2)O m(-2) s(-1)), indicating that the ozone concentration in substomatal cavities is higher in young seedlings than in trees. Significant changes in water use efficiency, as indicated by C(i)/C(a), occurred in trees between ages 5 and 20 years. We conclude that giant sequoias seedlings are sensitive to atmospheric ozone until they are about 5 years old. Low conductance, high water use efficiency, and compact mesophyll all contribute to a natural ozone tolerance, or defense, or both, in foliage of older trees.

  16. 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

    Directory of Open Access Journals (Sweden)

    Wan-Chi eWong

    2014-05-01

    Full Text Available 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.

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

    Science.gov (United States)

    Iizuka, Akira; Nakamura, Kazuhiro; Hirai, Hirokazu

    2015-04-10

    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.

  18. Rapid sexual maturity and short life span in the blue-legged frog and the rainbow frog from the arid Isalo Massif, southern-central Madagascar.

    Science.gov (United States)

    Guarino, Fabio M; Tessa, Giulia; Mercurio, Vincenzo; Andreone, Franco

    2010-12-01

    Longevity and age at sexual maturity were estimated in two anurans from the arid Isalo Massif (southern-central Madagascar), the blue-legged frog (Mantella expectata) and the rainbow frog (Scaphiophryne gottlebei). Phalanges from 69 individuals of M. expectata and 38 individuals of S. gottlebei were analyzed, using the skeletochronological method, in samples collected during two periods: January-February and November-December 2004. The male gonads of both species were also analyzed in order to better correlate reproductive activity with phenology. The phalangeal diaphysis in adults of both species was composed of two concentric bone layers: an innermost endosteal bone, which was less developed or sometimes lacking in S. gottlebei, and an outermost and broader layer of periosteal bone. Lines of arrested growth (LAGs) were observed in both species, although their recognition was more problematic and their distinctiveness much less evident in S. gottlebei. The results presented here indicate that M. expectata and S. gottlebei have a short life span and attain sexual maturity within the first active season after metamorphosis. Maximum longevity was 3 years in M. expectata and 2 years in S. gottlebei. In S. gottlebei the adult body size is likely attained during the same season in which metamorphosis occurs, but then breeding occurs only after the first latency period. Thus, mature individuals have only one LAG, corresponding to 1 year. The low number of individuals with two LAGs suggests that most animals die before the second latency period.

  19. Biomarkers of aging, life span and spontaneous carcinogenesis in the wild type and HER-2 transgenic FVB/N female mice.

    Science.gov (United States)

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

    2016-04-01

    FVB/N wild type and transgenic HER-2/neu FVB/N female mice breed at N.N. Petrov Research Institute of Oncology were under observation until natural death without any special treatment. Age-related dynamics of body weight, food consumption and parameters of carbohydrate and lipid metabolism, level of nitric oxide, malonic dialdehyde, catalase, Cu, Zn-superoxide dismutase, vascular endothelial growth factor were studied in both mice strains. The parameters of life span and tumor pathology were studied as well. Cancer-prone transgenic HER-2/neu mice developed in 100 % multiple mammary adenocarcinomas and died before the age of 1 year. Forty tree percent of long-lived wild type mice survived the age of 2 years and 19 %-800 days. The total tumor incidence in wild type mice was 34 %. The age-associated changes in the level of serum IGF-1, glucose and insulin started much earlier in transgene HER-2/neu mice as compared with wild type FVB/N mice. It was suggested that transgenic HER-2/neu involves in initiation of malignization of mammary epithelial cells but also in acceleration of age-related hormonal and metabolic changes in turn promoting mammary carcinogenesis.

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

    Science.gov (United States)

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

    2015-04-01

    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.

  1. 宋代皇子人数及寿命考%A Study on the Number and Life-span of the Princes in Song Dynasty

    Institute of Scientific and Technical Information of China (English)

    范帅

    2015-01-01

    The average life-span of the princes in Song dynasty was comparatively short and almost one third of them prematurely died.Two dominant causes for the death include the humiliation after being captured and the underdeveloped medical technology.Because of the frequent premature death,the contemporary people always introspected and summarized three causes such as religious sacrifices,misdiagnoses,and su-perstitions.Generally,there were more princes with higher survival rate in the North Song dynasty than those in the South Song dynasty.%宋代皇子的平均寿命较低,早亡皇子占皇子总数的近三分之一。宋代皇子寿命短主要有两大原因:一是被俘后屈辱而亡;二为医疗技术不够发达。面对皇子频频早亡,宋人经常自省,并从宗教祭祀、医官误诊和迷信风水三个方面寻找皇子夭折的原因。其中,北宋皇子人数多于南宋,成活率总体也高于南宋。

  2. Van Gogh and the life chart.

    Science.gov (United States)

    Rahe, R H

    1992-01-01

    Adolf Meyer originally devised the life chart in order to chronologically document a person's major life events and significant illness experiences over his or her life span. It is the purpose of this report to update Meyer's life chart through the presentation of the life events and illnesses of the famous artist Vincent Van Gogh. Van Gogh's life illustrates significant early (predisposing) life stresses, as well as clusterings of stressful (precipitating) life events occurring proximal to the occurrence of his several illnesses. Through the use of a life chart an understanding of why an individual becomes ill at a particular time in their life is enlarged. In addition, a systematic basis for formulating prognosis becomes available.

  3. TSG (2,3,5,4′-Tetrahydroxystilbene-2-O-β-D-glucoside from the Chinese Herb Polygonum multiflorum Increases Life Span and Stress Resistance of Caenorhabditis elegans

    Directory of Open Access Journals (Sweden)

    Christian Büchter

    2015-01-01

    Full Text Available 2,3,5,4′-Tetrahydroxystilbene-2-O-β-D-glucoside (TSG was isolated from Polygonum multiflorum, a plant which is traditionally used as an anti-ageing drug. We have analysed ageing-related effects of TSG in the model organism C. elegans in comparison to resveratrol. TSG exerted a high antioxidative capacity both in a cell-free assay and in the nematode. The antioxidative capacity was even higher compared to resveratrol. Presumably due to its antioxidative effects, treatment with TSG decreased the juglone-mediated induction of the antioxidative enzyme SOD-3; the induction of the GST-4 by juglone was diminished slightly. TSG increased the resistance of C. elegans against lethal thermal stress more prominently than resveratrol (50 μM TSG increased mean survival by 22.2%. The level of the ageing pigment lipofuscin was decreased after incubation with the compound. TSG prolongs the mean, median, and maximum adult life span of C. elegans by 23.5%, 29.4%, and 7.2%, respectively, comparable to the effects of resveratrol. TSG-mediated extension of life span was not abolished in a DAF-16 loss-of-function mutant strain showing that this ageing-related transcription factor is not involved in the effects of TSG. Our data show that TSG possesses a potent antioxidative capacity, enhances the stress resistance, and increases the life span of the nematode C. elegans.

  4. Chronological objects in demographic research

    Directory of Open Access Journals (Sweden)

    Frans J. Willekens

    2013-03-01

    Full Text Available BACKGROUND Calendar time, age and duration are chronological objects. They represent an instant or a time period. Age and duration are usually expressed in units with varying lengths. The number of days in a month or a year depends on the position on the calendar. The units are also not homogeneous and the structure influences measurement. One solution, common in demography, is to use units that are large enough for the results not to be seriously affected by differences in length and structure. Another approach is to take the idiosyncrasy of calendars into account and to work directly with calendar dates. The technology that enables logical and arithmetic operations on dates is available. OBJECTIVE To illustrate logical and arithmetic operations on dates and conversions between time measurements. METHODS Software packages include utilities to process dates. I use existing and a few new utilities in R to illustrate operations on dates and conversions between calendar dates and elapsed time since a reference moment or a reference event. Three demographic applications are presented. The first is the impact of preferences for dates and days on demographic indicators. The second is event history analysis with time-varying covariates. The third is microsimulation of life histories in continuous time. CONCLUSIONS The technology exists to perform operations directly on dates, enabling more precise calculations of duration and elapsed time in demographic analysis. It eliminates the need for (a approximations and (b transformations of dates, such as Century Month Code, that are convenient for computing durations but are a barrier to interpretation. Operations on dates, such as the computation of age, should consider time units of varying length.

  5. 闵尔昌《江子屏先生年谱》校点二种正误%Correction to the Emendations and Punctuations of a Chronological Life of Mr. Jiang Ting by Min Erchang

    Institute of Scientific and Technical Information of China (English)

    高明峰

    2012-01-01

    A Chronological Life of Mr. Jiang Ziping by 1VAn Erchang is important in the study of Jiang Fan and even the academy in Qing dynasty, which has been collated by Qi Yongxiang, and also by Zheng Xiaoxia and Wu Ping. Qi's revision has 29 errors, including 14 word-missings, 6 abundant words, 8 word faults, 1 inverted mistake, as well as 8 punctuation errors, including 5 period and comma mistakes and 3 wrong marks. The version by Zheng X aoxia and Wu Ping have the following two problems: the wrong note format and punctuation errors.%闵尔昌《江子屏先生年谱》是研究江藩乃至清代学术的重要资料。漆永祥和郑晓霞、吴平分别对其进行了校点整理。漆永祥校点本存在文字错误共有29处,含脱误14处,衍误6处,讹误8处,倒误1处。另有标点错误8处,含句逗不当5处,专名线标示不当3处。郑晓霞、吴平标点本存在闵尔昌《江子屏先生年谱》注文标识不当以及标点失误两大问题。

  6. The boundary of the chronology violating set

    CERN Document Server

    Minguzzi, E

    2016-01-01

    A sufficiently general definition for the future and past boundaries of the chronology violating region is given. In comparison to previous studies, this work does not assume that the complement of the chronology violating set is globally hyperbolic. The boundary of the chronology violating set is studied and several propositions are obtained which confirm the reasonability of the definition. Some singularity theorems related to chronology violation are considered.

  7. Comparing records with related chronologies

    Science.gov (United States)

    Bronk Ramsey, Christopher; Albert, Paul; Kearney, Rebecca; Staff, Richard A.

    2016-04-01

    In order to integrate ice, terrestrial and marine records, it is necessary to deal with records on different timescales. These timescales can be grouped into those that use a common fundamental chronometer (such as Uranium-Thorium dating or Radiocarbon) and can also be related to one another where we have chronological tie points such as tephra horizons. More generally we can, through a number of different methodologies, derive relationships between different timescales. A good example of this is the use of cosmogenic isotope production, specifically 10Be and 14C to relate the calibrated radiocarbon timescale to that of the Greenland ice cores. The relationships between different timescales can be mathematically expressed in terms of time-transfer functions. This formalism allows any related record to be considered against any linked timescale with an appropriate associated uncertainty. The prototype INTIMATE chronological database allows records to be viewed and compared in this way and this is now being further developed, both to include a wider range of records and also to provide better connectivity to other databases and chronological tools. These developments will also include new ways to use tephra tie-points to constrain the relationship between timescales directly, without needing to remodel each associated timescale. The database as it stands allows data for particular timeframes to be recalled and plotted against any timescale, or exported in spreadsheet format. New functionality will be added to allow users to work with their own data in a private space and then to publish it when it has been through the peer-review publication process. In order to make the data easier to use for other further analysis and plotting, and with data from other sources, the database will also act as a server to deliver data in a JSON format. The aim of this work is to make the comparison of integrated data much easier for researchers and to ensure that good practice in

  8. Communicating employability enchancement throughout the life-span: a national intervention program aimed at combating age-related stereotypes at the workplace

    NARCIS (Netherlands)

    M. van Selm; B.I.J.M. van der Heijden

    2013-01-01

    The stimulation of lifelong employability of employees is one of today's challenges in all sectors of the Dutch society. In this article, we will outline the historical context of the life-long employability issue in the Netherlands, and provide an overview of current business responses to the issue

  9. Communicating Employability Enhancement Throughout the Life-Span: A National Intervention Program Aimed at Combating Age-Related Stereotypes at the Workplace

    NARCIS (Netherlands)

    Selm, van Martine; Heijden, van der B.I.J.M.

    2013-01-01

    The stimulation of lifelong employability of employees is one of today's challenges in all sectors of the Dutch society. In this article, we will outline the historical context of the life-long employability issue in the Netherlands, and provide an overview of current business responses to the issue

  10. Effects of zinc on the life span and reproductive capacity and the hereditability influence of D.melanogaster%锌对果蝇寿命及生殖力的影响及其可遗传性

    Institute of Scientific and Technical Information of China (English)

    毛雪; 郭欣欣; 张敏

    2012-01-01

    This paper is engaged in the study of zinc effects on the life span and reproduction capability and the hereditability influence of D. melanogaster. As is known, as a trace element, zinc has something to do with the enzyme structure and may act as an enzyme activator or regulator of the endocrine hormone participating in organism metabolism, such as that of protein, amino acid, nucleic acid, fat, carbohydrate, vitamin and other nutritious elements. Laboratory analysis shows that zinc can play an important role in skeletal development, reproduction, immune, biological membrane stability, and functions as a gene denominator, cell proliferator and differentiator. Therefore, zinc deficiency or excess in animal or human bodies may affect their growth, developmenl and reproduction. However, it is not clear how different concentration of zinc would affect the somatic longevity and reproduction capability under the experimental conditions, letting alone make sure if the effect can be hereditary. Therefore, we suggest using the fruit fly (Drosophila melanogaster) to sludy the life span and it? reproduction capability after zinc being treated by survival tests and statistical methods. In doing so, we have added zinc to the culture medium of parental Drosophila at a concentration of 0.026 g/L, 0.052 g/L, 0.104 g/L and 0.260 g/L. Then, the life span and reproduction capability of parental Drosophila after being treated with the first filial Drosophila untreated analyzed separately. The results show that zinc treatment at low concentrations (added to the culture medium at a concentration of 0.026 g/L, 0.052 g/L, 0.104 g/L) tends to extend the average life-span, middle life-span, maximum life-span and 90% lethal time in parental and the first filial Drosophila, with treatment of 0.052 g/L zinc showing the best significant effects. On the contrary, high dosage zinc treatment (0.260 g/L) tends to shorten the life-span of Drosophila significantly, and suppress their reproduction

  11. 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

    Science.gov (United States)

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

    2000-01-01

    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.

  12. Deep sea minerals prolong life span of streptozotocin-induced diabetic rats by compensatory augmentation of the IGF-I-survival signaling and inhibition of apoptosis.

    Science.gov (United States)

    Liao, Hung-En; Shibu, Marthandam Asokan; Kuo, Wei-Wen; Pai, Pei-Ying; Ho, Tsung-Jung; Kuo, Chia-Hua; Lin, Jing-Ying; Wen, Su-Ying; Viswanadha, Vijaya Padma; Huang, Chih-Yang

    2016-07-01

    Consumption of deep sea minerals (DSM), such as magnesium, calcium, and potassium, is known to reduce hypercholesterolemia-induced myocardial hypertrophy and cardiac-apoptosis and provide protection against cardiovascular diseases. Heart diseases develop as a lethal complication among diabetic patients usually due to hyperglycemia-induced cardiac-apoptosis that causes severe cardiac-damages, heart failure, and reduced life expectancy. In this study, we investigated the potential of DSM and its related cardio-protection to increase the life expectancy in diabetic rats. In this study, a heart failure rat model was developed by using streptozotocin (65 mg kg(-1) ) IP injection. Different doses of DSM-1× (37 mg kg(-1) day(-1) ), 2× (74 mg kg(-1) day(-1) ) and 3× (111 mg kg(-1) day(-1) ), were administered to the rats through gavages for 4 weeks. The positive effects of DSM on the survival rate of diabetes rats were determined with respect to the corresponding effects of MgSO4 . Further, to understand the mechanism by which DSM enhances the survival of diabetic rats, their potential to regulate cardiac-apoptosis and control cardiac-dysfunction were examined. Echocardiogram, tissue staining, TUNEL assay, and Western blotting assay were used to investigate modulations in the myocardial contractile function and related signaling protein expression. The results showed that DSM regulate apoptosis and complement the cardiomyocyte proliferation by enhancing survival mechanisms. Moreover DSM significantly reduced the mortality rate and enhanced the survival rate of diabetic rats. Experimental results show that DSM administration can be an effective strategy to improve the life expectancy of diabetic subjects by improving cardiac-cell proliferation and by controlling cardiac-apoptosis and associated cardiac-dysfunction. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 769-781, 2016.

  13. 直链烷基苯磺酸钠对黑腹果蝇生殖能力及寿命的影响%Effect of linear alkylbenzenesulfonate on the reproductive capacity and life-span of drosophila melanogaster

    Institute of Scientific and Technical Information of China (English)

    赵文红; 张鼎; 周纯先; 江城梅

    2011-01-01

    Objective To investigate the effect of linear alkylbenzenesulfonate (LAS) on the reproductive capacity and life-span of drosophila melanogaster. Methods Drosophila melanogaster imagoes within 8 h after eclosion were collected with ether anesthesia. The female and male of similar size and normal shape and behavior were selected. The drosophila melanogasters were cultured in the culture medium containing LAS of different densities. We divided the drosophila melanogaster into 4 groups according to LAS concentrations: a low dose group with LAS 150 mg/kg, a middle dose group with LAS 300 mg/kg, a high dose group with LAS 600 mg/kg, and a control group without LAS, respectively. The changes of the reproductive capacity, median lethal time, mean lifespan and max mean life-span of drosophila melanogaster with different doses of LAS were measured and compared with those of the control. Results The pupa numbers of filial generation of drosophila melanogaster in the low, middle,and high dose groups (85.07% ,84.59% and 71.88%, respectively) were lower than those in the control group (P <0.01 ). The median lethal time, mean lifespan and max mean life-span of drosophila melanogaster in the low, middle, and high dose groups were shorter than those in the control group ( P < 0.05 ). The change of life-span of drosophila melanogaster in the high dose group was remarkable: the median lethal time of female and male shortened 13 days and 15 days, the mean life-span of female and male shortened 18 days and 14 days,and the max mean life-span of female and male shortened 14 days and 12 days, respectively. Conclusion LAS has definite toxicity to drosophila melanogaste, which can degrade the reproductive capacity of drosophila melanogaste and shorten the life-span of drosophila melanogaste.%目的:探讨直链烷基苯磺酸钠(linear alkylbenzenesulfonate,LAS)对果蝇生殖能力及寿命的影响.方法:采用乙醚麻醉的方法,收集8 h内羽化而未交配的野生型黑

  14. 'The brain is the organ of longevity': Introduction to G. A. Sacher's free-energy hypothesis of life-span enhancement

    Energy Technology Data Exchange (ETDEWEB)

    Justesen, D.R.

    1981-10-01

    No experiment reported to date constitutes an adequate test in the sense of supplying comprehensive information on survival time, metabolic rate, food consumption and utilization, body mass, anatomical integrity (especially that of the skeletal and nervous systems), status of the immune and endocrine systems, and physiological and behavioral competence in the wake of chronic exposure to a moderately thermalizing radio field. Some reports do provide data on one or more of the important end points, usually in association with a single exposure or a limited number of brief exposures. One must distinguish between prolongation of life in senescence and enhancement of longevity based on actual retardation of the rate of aging. More, retardation of aging, if sorely taxed at the expense of quality of living, is no bargain. Some hibernators live relatively long lives, but the torpor of hibernation--a prolonged period of somnolence and greatly reduced metabolic activity--is hardly the stuff of a vibrant psychological existence.

  15. Time in tortoiseshell: a bomb radiocarbon-validated chronology in sea turtle scutes.

    Science.gov (United States)

    Van Houtan, Kyle S; Andrews, Allen H; Jones, T Todd; Murakawa, Shawn K K; Hagemann, Molly E

    2016-01-13

    Some of the most basic questions of sea turtle life history are also the most elusive. Many uncertainties surround lifespan, growth rates, maturity and spatial structure, yet these are critical factors in assessing population status. Here we examine the keratinized hard tissues of the hawksbill (Eretmochelys imbricata) carapace and use bomb radiocarbon dating to estimate growth and maturity. Scutes have an established dietary record, yet the large keratin deposits of hawksbills evoke a reliable chronology. We sectioned, polished and imaged posterior marginal scutes from 36 individual hawksbills representing all life stages, several Pacific populations and spanning eight decades. We counted the apparent growth lines, microsampled along growth contours and calibrated Δ(14)C values to reference coral series. We fit von Bertalanffy growth function (VBGF) models to the results, producing a range of age estimates for each turtle. We find Hawaii hawksbills deposit eight growth lines annually (range 5-14), with model ensembles producing a somatic growth parameter (k) of 0.13 (range 0.1-0.2) and first breeding at 29 years (range 23-36). Recent bomb radiocarbon values also suggest declining trophic status. Together, our results may reflect long-term changes in the benthic community structure of Hawaii reefs, and possibly shed light on the critical population status for Hawaii hawksbills.

  16. 亚硝酸钠对果蝇寿命影响及Vc拮抗作用研究%Effect of sodium nitrite and Vc on life-span of Drosophila nelanogaste

    Institute of Scientific and Technical Information of China (English)

    张书玲; 董丽军; 王瑞强

    2011-01-01

    以黑腹果蝇(Drosophila melanogaster)为试验材料,探讨了亚硝酸钠对果蝇寿命的影响及维生素C(Vc)的拮抗作用.结果表明:培养基中添加亚硝酸钠可以显著缩短果蝇的平均寿命,添加30、120和480 mg/mL亚硝酸钠处理组的雌果蝇平均寿命分别减少17.60%、44.47%和68.52%,雄性果蝇分别减少4.71%、19.19%和65.95%;在添加480 mg/mL亚硝酸钠的培养基中加入不同浓度Vc,果蝇的平均寿命随Vc浓度的提高而显著延长,其中Vc浓度为0.13%、0.40%、1.20%处理组的雌性果蝇平均寿命分别增加了19.61%、73.63%和114.13%,雄性果蝇分别增加了0.35%、27.49%和137.59%;生化分析显示,果蝇体内SOD活性随Vc浓度的升高而显著增加,而MDA含量随Vc浓度的升高而显著降低.%Fruit flies (Drosophila melanogaster) were used as the experimental material to study the effects of sodium nitrite on life-span and mechanism of antagonism of Vc on sodium nitrite. The results showed that the average life-span of D. melanogaster was significantly shortened in medium with different concentration of sodium nitrite. The average life-span decreased by 17.60%, 44.47% and 68.52% for the female D. melanogaster and 4.71%,19.19% and 65.95% for the male D. melanogaster when the concentration of sodium nitrite was 30 mg/mL,120 mg/mL, and 480 mg/mL. But, when the concentration of Vc was 0.13%, 0.40% and 1.20% in the Medium with 480 mg/mL sodium nitrite, the life-span increased 19.61%,73.63% and 114.13% for female melanogaster, and 0.35%, 27.49% and 137.59% for male D. melanogaster, respectively. With the concentration of Vc increased, the SOD activities increased and the MDA content decreased in both male and female melanogaster significantly.

  17. 火麻仁油及甾醇对家蚕寿命影响的观察%Observation of Influence of Semen Cannabis Oil and Sterol on Bombyx Mori Linnaeus Life-span

    Institute of Scientific and Technical Information of China (English)

    李寒冰; 孙静雅; 马永洁; 李根林; 任慧玲

    2012-01-01

    目的:观察火麻仁油及火麻仁甾醇对家蚕寿命的影响,探讨火麻仁油及甾醇的抗衰老作用.方法:取龄期相同、生长整齐的三眠蚕随机分为8组,即空白对照组,火麻仁油高、中、低剂量组,火麻仁甾醇高、中、低剂量组,维生素E对照组,每组110条.使用涂抹法将药液涂抹于新鲜桑叶上,4龄期内喂食3次,5龄期内喂食6次.结果:火麻仁油及甾醇高、中、低剂量组均对家蚕幼虫生存期较空白对照组明显延长(P<0.01或P<0.05),其中火麻仁甾醇能显著延长家蚕全生存期(P<0.01或P<0.05).与空白组相比,火麻仁油及甾醇均能显著延长5龄期家蚕耐饥饿时间(P<0.01).结论:火麻仁油及甾醇均能够延长家香各龄期生存期时间.%Objective:To observe the influence of Semen Cannabis oil and sterol on bombyx mori linnaeus life-span and discuss their anti-aging effect. Methods: Sanmian silkworm with the same age and growth were randomly divided into eight groups, namely blank control group, high, middle, low dose of Semen Cannabis oil group, high, meddle, low dose of Semen Cannabis oil and sterol group, positive control group. Physic liquor is daubed on the mulberry leaf ,3 times during 4 instars and 6 times during 5 instars. Results:The life-span of bombyx mori linnaeus larva was significantly longer in high, meddle, low dose of Semen Cannabis oil and sterol group compared with control group(P<0.01 or P<0.05). Semen Cannabis oil and sterol can significantly extend the all life span(P<0.01 or P<0.05). Compared with the blank control group, Semen Cannabis oil and sterol can significantly extend the hunger resistance time during 5 instars (P <0.01), Conclusion:both Semen Cannabis oil and sterol can extend the life span time of bombyx mori Linnaeus during any instars.

  18. ERP correlates of script chronology violations.

    Science.gov (United States)

    Baetens, Kris; Van der Cruyssen, Laurens; Vandekerckhove, Marie; Van Overwalle, Frank

    2014-11-01

    Research indicates a distinction between the processing of script content (which events, behaviors, scenes… are part of it) and script chronology (what is their usual order of occurrence). Using sequences of two line drawings depicting everyday social script events, we examined the event related potential (ERP) correlates of script chronology violations (i.e., wrong order). An increased left anterior negativity (LAN) following chronology violations suggests similarities between the processing of script chronology in visually observed human behavior and verbal syntax. Consequently, this study extends previous findings suggesting that the LAN is sensitive to structure violation across domains (e.g., verbal syntax, abstract structure), including that of meaningful human actions.

  19. Leaf life spans of some conifers of the temperate forests of South America Longevidad foliar de algunas coníferas de los bosques templados de Sudamérica

    Directory of Open Access Journals (Sweden)

    CHRISTOPHER H. LUSK

    2001-09-01

    Full Text Available Interspecific variation in leaf life span has wide-ranging implications for plant species sorting on resource availability gradients, and for ecosystem processes such as nutrient cycling. Very little is known about leaf life spans of evergreen trees in the temperate forests of South America. Leaf life spans were estimated by static demographic methods, and associated leaf traits measured, for four conifers of this region. It was expected that leaf life span variation would correlate negatively with soil fertility of habitats normally occupied by each species. This prediction was upheld by the data. The mean leaf life span determined for Araucaria araucana (24 years is among the highest figures reported for any plant species. This extreme leaf longevity was associated with very robust construction (high leaf mass per unit area and very low nitrogen content. These aspects of the ecology of A. araucana may affect its fitness in two ways. Firstly, slow foliage turnover will reduce its annual nutrient requirements for crown maintenance, a trait that is thought to be crucial for survival on nutrient-poor sites. Secondly, the low decomposability of A. araucana leaf litter is likely to cause nutrient immobilisation, possibly favouring site retention by A. araucana in the face of competition from faster-growing but more nutrient-demanding species. Interspecific variation in leaf life span appeared to be systematically related to variation in leaf mass per unit area (LMA and leaf nitrogen, in agreement with a large body of evidence that leaf evolution is constrained by a trade-off between trait combinations which optimise carbon gain and growth in resource-rich habitats, and those which favour persistence in chronically adverse environmentsLas diferencias específicas en longevidad foliar tienen importantes implicancias para la distribución de las plantas en relación con gradientes de recursos, y en procesos ecosistémicos tales como el ciclaje de

  20. Astronomical arguments in Newton's Chronology

    CERN Document Server

    Naze, Yael

    2012-01-01

    In his Chronology, Newton uses astronomical "evidence" to support its extreme rejuvenation of ancient times. These elements, having a scientific varnish, provide some credibility to the work. They have been fiercely debated for a century, with a gradual undermining of Newton's assumptions. However, this has not dented the prestige of the English scientist. ----- Dans sa Chronologie, Newton utilise des "preuves" astronomiques pour appuyer son rajeunissement extreme des epoques anciennes. Ces elements, au vernis scientifique, donnent une credibilite certaine a l'ensemble. Ils ont donc ete aprement discutes, les debats sapant petit a petit les hypotheses du savant anglais pour finalement porter un coup mortel a l'ensemble. Cela n'a toutefois pas entame le prestige du savant anglais.

  1. 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

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, R.C.

    1989-01-01

    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.

  2. The Relation between Big Five Traits and Well-being across the Life Span%不同年龄群体大五人格与幸福感关系

    Institute of Scientific and Technical Information of China (English)

    陈志霞; 李启明

    2014-01-01

    以毕生发展为研究视角,调查了3192位不同年龄群体被试,探讨不同年龄群体大五人格与幸福感的关系。结果发现:(1)各变量都存在显著的年龄效应,大五人格与主观幸福感相关显著;(2)在不同年龄群体里,神经质和开放性都能显著预测主观幸福感,且预测值随着年龄而增大,而外倾性、尽责性和宜人性对主观幸福感的预测存在年龄差异;(3)大五人格对主观幸福感的解释率随着年龄的增长而下降,到60岁之后其解释率上升;(4)年龄在大五人格与主观幸福感之间起了显著的调节作用。%In the current study, we examine the relationship between personality traits and subjective well-being and psy-chological well-being from a life span perspective.A total of 3192 Chinese residents took part in this study from 41 cities in the country 17 provinces and municipalities.And they completed the subjective well-being scale and big five-factor inventory.It took about 20 minutes to complete the questionnaires.The correlations among factors were calculated with SPSS 16.0 and Structural equation model was applied to deal with all data.In the analysis of struc-tural equation modeling, seven models were constructed.As predicted, personality traits were significantly associat-ed with subjective well-being with the different age groups of Chinese residents.And then Structural equation mod-els revealed that ages play a moderating role between personality traits and subjective well-being, and the total effect value was different.In conclusion, this research indicates that personality traits were associated with greater happiness across the life span, and personality traits were one of the best predictors.This study provides new in-sights into personal traits as predictors of well-being.Especially, this study addressed some limitations of previous studies.Importantly, this study also helps clarify questions about

  3. Life Span Personality Stability in Sibling Statuses.

    Science.gov (United States)

    Rosenberg, B. G.

    Personality stability and change in sibling status in the one- and two-child-family are examined in this Study. Q-sort data were analyzed for the same 33 male and 34 female subjects during four periods of their lives-- early and late adolescence and early and middle adulthood. Results indicate that stability of personality was greatest during…

  4. Climate wavelet spectrum estimation under chronology uncertainties

    Science.gov (United States)

    Lenoir, G.; Crucifix, M.

    2012-04-01

    Several approaches to estimate the chronology of palaeoclimate records exist in the literature: simple interpolation between the tie points, orbital tuning, alignment on other data... These techniques generate a single estimate of the chronology. More recently, statistical generators of chronologies have appeared (e.g. OXCAL, BCHRON) allowing the construction of thousands of chronologies given the tie points and their uncertainties. These techniques are based on advanced statistical methods. They allow one to take into account the uncertainty of the timing of each climatic event recorded into the core. On the other hand, when interpreting the data, scientists often rely on time series analysis, and especially on spectral analysis. Given that paleo-data are composed of a large spectrum of frequencies, are non-stationary and are highly noisy, the continuous wavelet transform turns out to be a suitable tool to analyse them. The wavelet periodogram, in particular, is helpful to interpret visually the time-frequency behaviour of the data. Here, we combine statistical methods to generate chronologies with the power of continuous wavelet transform. Some interesting applications then come up: comparison of time-frequency patterns between two proxies (extracted from different cores), between a proxy and a statistical dynamical model, and statistical estimation of phase-lag between two filtered signals. All these applications consider explicitly the uncertainty in the chronology. The poster presents mathematical developments on the wavelet spectrum estimation under chronology uncertainties as well as some applications to Quaternary data based on marine and ice cores.

  5. Effect of Resveratrol on Life-span and Antioxidation in Drosophila Melanogaster%白藜芦醇对果蝇寿命和抗氧化能力的影响

    Institute of Scientific and Technical Information of China (English)

    刘贵珊; 张泽生; 杨博; 贺伟

    2013-01-01

      To discuss the effect of resveratrol on the life-span and the antioxidation in Drosophila melanogaster , newly eclosed male fruit flies were divided randomly into 4 groups , which were treated with different concentration (0,2.5,5,10 mg/mL) of resveratrol . In lifespan study , dead flies were counted every three days until all flies died. The lifespan , the activities of superoxide dismutase (SOD), catalase (CAT) and the content of malondialdehyde (MDA) were determined. The experimental results show that resveratrol extends the maximum lifespan and mean lifespan of Drosophila melanogaster , exhibiting a dosage effect . The activities of SOD and CAT increase, meanwhile the content of MDA decreases in the experiment. The Conclusions prove that resveratrol can increase antioxidative effect , reduce lipid peroxidation and prolong the life-span in Drosophila.%  探讨白藜芦醇对黑腹果蝇寿命和抗氧化功能的影响。将2d龄雄性果蝇随机分组,用涂布了不同剂量的白藜芦醇(0、2.5、5、10 mg/mL)的培养基饲喂果蝇,每隔3天记录果蝇死亡数,直至全部死亡。测定白藜芦醇对果蝇寿命和超氧化物歧化酶(SOD)活性、过氧化氢酶(CAT)活性以及丙二醛(MDA)含量的影响。研究结果表明:饲喂白藜芦醇后,果蝇最高寿命及平均寿命均随剂量的增大而延长,提高了SOD和CAT活性,降低了MDA含量。说明白藜芦醇可以提高果蝇的抗氧化能力,抑制脂质过氧化,延长果蝇寿命。

  6. Extravehicular Activity Fact Sheet: An EVA Chronology

    Data.gov (United States)

    National Aeronautics and Space Administration — Walking to Olympus: An EVA Chronology chronicles the 154 EVAs conducted from March 1965 to April 1997. It is intended to make clear the crucial role played by EVA in...

  7. Low doses of paraquat and polyphenols prolong life span and locomotor activity in knock-down parkin Drosophila melanogaster exposed to oxidative stress stimuli: implication in autosomal recessive juvenile parkinsonism.

    Science.gov (United States)

    Bonilla-Ramirez, Leonardo; Jimenez-Del-Rio, Marlene; Velez-Pardo, Carlos

    2013-01-10

    Previous studies have shown that polyphenols might be potent neuroprotective agents in Drosophila melanogaster wild type Canton-S acutely or chronically treated with paraquat (PQ), a selective toxin for elimination of dopaminergic (DAergic) neurons by oxidative stress (OS), as model of Parkinson's disease (PD). This study reports for the first time that knock-down (K-D) parkin Drosophila melanogaster (TH-GAL4; UAS-RNAi-parkin) chronically exposed to PQ (0.1-0.25 mM), FeSO(4) (Fe, 0.1mM), deferoxamine (DFO, 0.01 mM) alone or (0.1mM) PQ in combination with polyphenols propyl gallate (PG, 0.1mM) and epigallocathecin gallate (EGCG, 0.1, 0.5mM) showed significantly higher life span and locomotor activity than untreated K-D flies or treated with (1, 5, 20mM) PQ alone. Whilst gallic acid (GA, 0.1, 0.5mM) alone or in the presence of PQ provoked no effect on K-D flies, epicathecin (EC, 0.5mM) only showed a positive effect on prolonging K-D flies' life span. It is shown that PG (and EGCG) protected protocerebral posterolateral 1 (PPL1) DAergic neurons against PQ. Interestingly, the protective effect of low PQ concentrations, DFO and iron might be explained by a phenomenon known as "hormesis." However, pre-fed K-D flies with (0.1mM) PQ for 7 days and then exposed to (0.25 mM) for additional 8 days affect neither survival nor climbing of K-D Drosophila compared to flies treated with (0.25 mM) PQ alone. Remarkably, K-D flies treated with 0.1mM PQ (7 days) and then with (0.25 mM) PQ plus PG (8 days) behaved almost as flies treated with (0.25 mM) PQ. Taken these data suggest that antioxidant supplements that synergistically act with low pro-oxidant stimuli to prolong and increase locomotor activity become inefficient once a threshold of OS has been reached in K-D flies. Our present findings support the notion that genetically altered Drosophila melanogaster as suitable model to study genetic and environmental factors as causal and/or modulators in the development of autosomal

  8. Effects of Sodium Nitrite on Life-span, Superoxide Dismutase Activity and Malondialdehyde Content in Drosophila Melanogaster%亚硝酸钠对果蝇寿命及SOD和MDA的影响

    Institute of Scientific and Technical Information of China (English)

    张书玲; 董丽军; 刘龙

    2011-01-01

    In this study, Drosophila melanogaster was used as the experimental animal to study the. effects of sodium nitrite on life-span, superoxide dismutase (SOD) activity and malondialdehyde (MDA) content in D. melanogaster. The results showed that sodium nitrite significantly shortened drosophila average lifespan. The decreased average life-span of female D. melanogaster was 12.53,31.49 and 48.79 days when the concentrations of sodium nitrite were 30,120 and 480 g/L. Average life-span of the male was short ened 3.15 d, 12.83 and 44. 11 days, respectively. After cultured with the sodium nitrite, the activities of the SOD decreased and MDA content increased. Compared to the control group, the activities of the SOD of female D. melanogaster decreased 8. 52% ,31.06% and 41.69% or 14.79% ,34.64% ,and 47.78%(P <0.05 or P<0. 01) when D. melanogaster was fed with sodium nitrite at the concentration of 30,120 and 480g/L for 10d and 20d, while the MDA content increased 26. 94%, 48. 71%, 72. 02% and 20. 63%,40. 56% ,83.92% (P<0.05 or P<0. 01). The activities of the SOD of male D. melanogaster decreased 9. 47%, 34. 13%, 44. 62% and 11. 18%, 31.66%, 46. 10% while MDA content increased 21.74% ,48. 40% ,74.46% and 24.91% ,45.67% ,74.39%. Compared to the control group,SOD activity and MDA content significantly increased in sodium nitrite (P<0. 05 or P<O. 01) except for SOD activity of 30 g/L sodium nitrite experimental group after male D. melanogaster fed 10 days.%以果蝇(Drosophila melanogaster)为试验动物,探讨亚硝酸钠对果蝇寿命、超氧化物岐化酶(SOD)活性及丙二醛(MDA)含量的影响.结果表明:培养基中添加亚硝酸钠能显著缩短果蝇平均寿命,其中30//L、120g/L和480g/L组雌果蝇平均寿命与对照组相比分别缩短了12.53、31.49、48.79d,雄果蝇平均寿命与对照组相比分别缩短了3.15、12.83、44.11 d.饲喂亚硝酸钠后果蝇体内的SOD活性降低,MDA

  9. On the Astronomical Records and Babylonian Chronology

    CERN Document Server

    Gurzadyan, V G

    2000-01-01

    We outline the priority of high quality data of astronomical content as our strategy for the analysis of the ancient astronomical records in the search of the absolute chronology of the Near East in II millennium BC. The correspondingly defined set of data for two lunar eclipses of EAE 20 and 21 tablets linked to Ur III period enables us the choice of eclipses of 27 June 1954 BC and 17 March 1912 BC; here the information on the exit position of the darkening of the lunar disk acts as a crucial informator survived in the records. We then discuss why the 56/64 year Venus cycle cannot be traced in the Venus Tablet and therefore cannot serve as an anchor for the search of chronologies. The month length method is discussed as well. In sum the available data support the Ultra-Low Chronology proposed in the book by H.Gasche, J.A.Armstrong, S.W.Cole and V.G.Gurzadyan, "Dating the Fall of Babylon" (1998) and, particularly, leave no astronomical background for the High Chronology. Ultra-Low Chronology is supported also...

  10. Constraining the Cratering Chronology of Vesta

    CERN Document Server

    O'Brien, David P; Morbidelli, Alessandro; Bottke, William F; Schenk, Paul M; Russell, Christopher T; Raymond, Carol A

    2014-01-01

    Vesta has a complex cratering history, with ancient terrains as well as recent large impacts that have led to regional resurfacing. Crater counts can help constrain the relative ages of different units on Vesta's surface, but converting those crater counts to absolute ages requires a chronology function. We present a cratering chronology based on the best current models for the dynamical evolution of asteroid belt, and calibrate it to Vesta using the record of large craters on its surface. While uncertainties remain, our chronology function is broadly consistent with an ancient surface of Vesta as well as other constraints such as the bombardment history of the rest of the inner Solar System and the Ar-Ar age distribution of howardite, eucrite and diogenite (HED) meteorites from Vesta.

  11. Long Span Bridges in Scandinavia

    DEFF Research Database (Denmark)

    Gimsing, Niels Jørgen

    1998-01-01

    The first Scandinavian bridge with a span of more than 500 m was the Lillebælt Suspension Bridge opened to traffic in 1970.Art the end of the 20th century the longest span of any European bridge is found in the Storebælt East Bridge with a main span of 1624 m. Also the third longest span in Europe...... is found in Scandinavia - the 1210 m span of the Höga Kusten Bridge in Sweden.The Kvarnsund Bridge in Norway was at the completion in 1991 the longest cable-stayed bridge in the world, and the span of 530 m is still thge longest for cable-stayed bridges in concrete. The Øresund Bridge with its sapn of 490...... m is the longest among cable-stayed bridges for both road and railway traffic....

  12. Aging in elderly: Chronological versus photoaging

    Directory of Open Access Journals (Sweden)

    Priya Cinna Durai

    2012-01-01

    Full Text Available Background: Skin is a window to aging changes, a biological reality. There is a dearth of studies regarding the various chronological (intrinsic aging and photoaging (extrinsic changes seen in Asians. This study was undertaken to detect the clinical pattern of aging skin changes and dermatoses seen in the elderly. Materials and Methods: This was a descriptive study conducted on 500 consecutive elderly individuals attending the Dermatology out-patient department. The severity of photoaging was graded using Glogau scale. Results: Most of the population had skin type IV and V. Majority (415, 83% of our cases had chronological aging without photoaging and the remaining 85 (17% individuals had photoaging along with chronological aging. The common skin changes due to chronological aging were thin skin, fine wrinkles, xerosis, and loss of elasticity. Photoaging changes such as dyspigmentation, freckles, thick skin, deep wrinkles, melasma, citrine skin, senile purpura, pseudostellate scar, acrokeratoelastoidosis marginalis, and lentigines were less frequent in our study. Smoking and prolonged sun exposure was the risk factors aggravating photoaging. The most common dermatosis was pruritus in 248 (49.6% individuals, of which 149 (29.8% had pruritus associated with xerosis. Contact dermatitis was more common in males. Fungal infections were frequently seen in females. Seborrhoeic keratosis (253, 50.6% was the most common benign neoplasm more commonly seen in males. Cutaneous malignancies were less common in our study population. Conclusion: Photoaging changes were less common than chronological aging changes in skin type IV. Chronological changes were more frequent in females than males, while photoaging was more frequent in males.

  13. Tracking bacterial growth in liquid media and a new bacterial life model

    Institute of Scientific and Technical Information of China (English)

    刘实

    1999-01-01

    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 of Escherichia coli was continuously observed in real-time for up to 6 h. The observations showed primarily unidirectional growth and reproduction of E. coli and suggested more than one reproduction in the observed portion of E. coli life span. A new bacterial life model is proposed: each bacterium has a stable cell polarity that ultimately transforms into two bacteria of different generations; the life cycle of a bacterium can contain more than one reproduction cycle; and the age of a bacterium should be defined by its experienced chronological time. This new bacterial life model differs from the dominant concepts of bacterial life but complies with all basic life principles based on direct observation of macroorganisms.

  14. Effects of extracts from green tea on life - span and fecundity of Drosophila melanogaster%绿茶提取物对果蝇寿命和繁殖力的影响

    Institute of Scientific and Technical Information of China (English)

    赵锦慧; 陈璨; 师杨

    2012-01-01

    Drosophila melanogaster were divided into control group and treatment groups and treatment groups were fed with medium containing extracts from green tea, counted the number of live and death every day until all the Drosophila melanogaster died and calculated the mean and maximum lifespan, furthermore, paired male and female Drosophila melanogaster of no mating and cultivated them, counted up the number of imago of Drosophila melanogaster when the offsprings appeared. The results showed that low concentration extracts from green tea(3 mg/mL-6 mg/mL) could lengthen the mean and maximum lifespan, promote the fecundity of Drosophila melanogaster remarkably, however, high concentration extracts from green tea(12 mg/mL) could shorten the mean and maximum life - span, diminish the fecundity of Drosophila melanogaster.%采用乙醚麻醉法,收集8h内羽化的果蝇成虫,雌雄分开培养,随机分为对照组和处理组(绿茶提取物质量浓度分别为3mg/mL,6mg/mL,12mg/mL),每组饲喂相应的培养基,统计其寿命.另取未交配的雌雄果蝇成对放入培养基中,待出现子代成蝇时,统计成蝇数量,记录7d内成蝇羽化的数目,连续培养调查3代,观察绿茶提取物对果蝇繁殖力的影响.结果表明:绿茶提取物质量浓度为3mg/mL~6mg/mL时能显著延长果蝇平均寿命和最高寿命,并能显著提高果蝇繁殖力,质量浓度为12mg/mL时反而缩短果蝇寿命并降低果蝇繁殖力.

  15. Spanning trees crossing few barriers

    NARCIS (Netherlands)

    Asano, T.; Berg, M. de; Cheong, O.; Guibas, L.J.; Snoeyink, J.; Tamaki, H.

    2002-01-01

    We consider the problem of finding low-cost spanning trees for sets of n points in the plane, where the cost of a spanning tree is defined as the total number of intersections of tree edges with a given set of m barriers. We obtain the following results: (i) if the barriers are possibly intersecting

  16. Extension of yeast chronological lifespan by methylamine.

    Directory of Open Access Journals (Sweden)

    Sanjeev Kumar

    Full Text Available BACKGROUND: Chronological aging of yeast cells is commonly used as a model for aging of human post-mitotic cells. The yeast Saccharomyces cerevisiae grown on glucose in the presence of ammonium sulphate is mainly used in yeast aging research. We have analyzed chronological aging of the yeast Hansenula polymorpha grown at conditions that require primary peroxisome metabolism for growth. METHODOLOGY/PRINCIPAL FINDINGS: The chronological lifespan of H. polymorpha is strongly enhanced when cells are grown on methanol or ethanol, metabolized by peroxisome enzymes, relative to growth on glucose that does not require peroxisomes. The short lifespan of H. polymorpha on glucose is mainly due to medium acidification, whereas most likely ROS do not play an important role. Growth of cells on methanol/methylamine instead of methanol/ammonium sulphate resulted in further lifespan enhancement. This was unrelated to medium acidification. We show that oxidation of methylamine by peroxisomal amine oxidase at carbon starvation conditions is responsible for lifespan extension. The methylamine oxidation product formaldehyde is further oxidized resulting in NADH generation, which contributes to increased ATP generation and reduction of ROS levels in the stationary phase. CONCLUSION/SIGNIFICANCE: We conclude that primary peroxisome metabolism enhanced chronological lifespan of H. polymorpha. Moreover, the possibility to generate NADH at carbon starvation conditions by an organic nitrogen source supports further extension of the lifespan of the cell. Consequently, the interpretation of CLS analyses in yeast should include possible effects on the energy status of the cell.

  17. A Chronological History of Puerto Rico.

    Science.gov (United States)

    Tovar, Federico Ribes

    This book presents a chronological history of Puerto Rico from prehistory and discovery through December of 1972. It includes information on the persons and events that influenced the course of Puerto Rican history. A table of contents and a selective index are included. (Author/AM)

  18. Spanning Tree Based Attribute Clustering

    DEFF Research Database (Denmark)

    Zeng, Yifeng; Jorge, Cordero Hernandez

    2009-01-01

    inconsistent edges from a maximum spanning tree by starting appropriate initial modes, therefore generating stable clusters. It discovers sound clusters through simple graph operations and achieves significant computational savings. We compare the Star Discovery algorithm against earlier attribute clustering...

  19. Relationships between Categorical Perception of Phonemes, Phoneme Awareness, and Visual Attention Span in Developmental Dyslexia.

    Science.gov (United States)

    Zoubrinetzky, Rachel; Collet, Gregory; Serniclaes, Willy; Nguyen-Morel, Marie-Ange; Valdois, Sylviane

    2016-01-01

    We tested the hypothesis that the categorical perception deficit of speech sounds in developmental dyslexia is related to phoneme awareness skills, whereas a visual attention (VA) span deficit constitutes an independent deficit. Phoneme awareness tasks, VA span tasks and categorical perception tasks of phoneme identification and discrimination using a d/t voicing continuum were administered to 63 dyslexic children and 63 control children matched on chronological age. Results showed significant differences in categorical perception between the dyslexic and control children. Significant correlations were found between categorical perception skills, phoneme awareness and reading. Although VA span correlated with reading, no significant correlations were found between either categorical perception or phoneme awareness and VA span. Mediation analyses performed on the whole dyslexic sample suggested that the effect of categorical perception on reading might be mediated by phoneme awareness. This relationship was independent of the participants' VA span abilities. Two groups of dyslexic children with a single phoneme awareness or a single VA span deficit were then identified. The phonologically impaired group showed lower categorical perception skills than the control group but categorical perception was similar in the VA span impaired dyslexic and control children. The overall findings suggest that the link between categorical perception, phoneme awareness and reading is independent from VA span skills. These findings provide new insights on the heterogeneity of developmental dyslexia. They suggest that phonological processes and VA span independently affect reading acquisition.

  20. Chronology violation and the Cosmological Argument

    CERN Document Server

    Romero, G E

    2003-01-01

    The Kalam Cosmological Argument is perhaps the most solid and widly discussed argument for a caused creation of the universe. The usual objections to the argument mainly focus on the second premise. In this paper we discuss the dependency of the first premise on the topological structure of the space-time manifold adopted for the underlying cosmological model. It is shown that in chronology-violating space-times the first premise is also violated. The chronology-violation, in turn, requires a massive violation of the so-called energy conditions which could have observational effects that are briefly discussed here. Hence, astronomical observations could be relevant for the validity of the metaphysical argument. In this sense, it is possible to talk of "observational theology".

  1. A chronology of librarianship, 1960-2000

    CERN Document Server

    Wilhite, Jeffrey M

    2009-01-01

    This book covers all areas of library literature that inform the history of librarianship and ranges over multiple continents. Its broad scope lends itself to wide use by scholars and students of library history and library literature. The chronology is presented in a dictionary format and separated into decades. It is complemented by a comprehensive bibliography and both subject and name indexes, which are cross-listed for ease of use.

  2. Spatial variability in growth-increment chronologies of long-lived freshwater mussels: Implications for climate impacts and reconstructions

    Science.gov (United States)

    Black, Bryan A.; Dunham, Jason B.; Blundon, Brett W.; Raggon, Mark F.; Zima, Daniela

    2010-01-01

    Estimates of historical variability in river ecosystems are often lacking, but long-lived freshwater mussels could provide unique opportunities to understand past conditions in these environments. We applied dendrochronology techniques to quantify historical variability in growth-increment widths in valves (shells) of western pearlshell freshwater mussels (Margaritifera falcata). A total of 3 growth-increment chronologies, spanning 19 to 26 y in length, were developed. Growth was highly synchronous among individuals within each site, and to a lesser extent, chronologies were synchronous among sites. All 3 chronologies negatively related to instrumental records of stream discharge, while correlations with measures of water temperature were consistently positive but weaker. A reconstruction of stream discharge was performed using linear regressions based on a mussel growth chronology and the regional Palmer Drought Severity Index (PDSI). Models based on mussel growth and PDSI yielded similar coefficients of prediction (R2Pred) of 0.73 and 0.77, respectively, for predicting out-ofsample observations. From an ecological perspective, we found that mussel chronologies provided a rich source of information for understanding climate impacts. Responses of mussels to changes in climate and stream ecosystems can be very site- and process-specific, underscoring the complex nature of biotic responses to climate change and the need to understand both regional and local processes in projecting climate impacts on freshwater species.

  3. Chronological Records of Li Anzhai and Yu Shiyu

    Institute of Scientific and Technical Information of China (English)

    WANG Hongliang

    2013-01-01

    In the history of Chinese ethnolo-gy, Li Anzhai and Yu Shiyu were not only life partners, but also an important academic married couple, especially in Tibetology.Li Anzhai was not only a representative in frontier research in China , but also a core figure in the West China school of Anthropology .He also has an important position in the history of modern academics . Yu Shiyu had an extremely rich talent for languages , and was good at sorting out bibliographies .Moreo-ver, she was interested in field investigation , which laid a solid foundation for her research on Tibetology .She also provided important support for Li Anzhai’ s fieldwork in Tibetan areas.The cou-ple ’ s academic life blended with each other , and they could be regarded as “two birds with the same destination” ( tianya tongming niao) . The life of this couple can help us understand that their life was both manifested and hidden from view by the times, and their academic life was both created and destroyed by the times .With regard to their academic position and social impact , it was a pity that their academic research did not meet the expectation of academic circles . Within various works related to the review of the history of the dis-ciplines, the couple was always included , in spite of the fact that the introductions to them were al-ways very simple .Although they are mentioned in some sporadic works , most of these works are only introductory articles or book reviews . Up until now, no one has systematically researched their life and academic thought .Hence, the author, by combing through various documents and archives , gives a chronological record of Li Anzhai ’ s and Yu Shiyu ’ s life story and academic achievements in order to provide basic historical data for academ-ic circles to carry out further research on the histo-ry of the discipline .

  4. A distributed spanning tree algorithm

    DEFF Research Database (Denmark)

    Johansen, Karl Erik; Jørgensen, Ulla Lundin; Nielsen, Svend Hauge

    1988-01-01

    We present a distributed algorithm for constructing a spanning tree for connected undirected graphs. Nodes correspond to processors and edges correspond to two way channels. Each processor has initially a distinct identity and all processors perform the same algorithm. Computation as well...... as communication is asyncronous. The total number of messages sent during a construction of a spanning tree is at most 2E+3NlogN. The maximal message size is loglogN+log(maxid)+3, where maxid is the maximal processor identity....

  5. A Distributed Spanning Tree Algorithm

    DEFF Research Database (Denmark)

    Johansen, Karl Erik; Jørgensen, Ulla Lundin; Nielsen, Sven Hauge

    We present a distributed algorithm for constructing a spanning tree for connected undirected graphs. Nodes correspond to processors and edges correspond to two-way channels. Each processor has initially a distinct identity and all processors perform the same algorithm. Computation as well...... as communication is asynchronous. The total number of messages sent during a construction of a spanning tree is at most 2E+3NlogN. The maximal message size is loglogN+log(maxid)+3, where maxid is the maximal processor identity....

  6. Lake trout otolith chronologies as multidecadal indicators of high-latitude freshwater ecosystems

    Science.gov (United States)

    Black, B.A.; Von Biela, V.R.; Zimmerman, C.E.; Brown, Randy J.

    2013-01-01

    High-latitude ecosystems are among the most vulnerable to long-term climate change, yet continuous, multidecadal indicators by which to gauge effects on biology are scarce, especially in freshwater environments. To address this issue, dendrochronology (tree-ring analysis) techniques were applied to growth-increment widths in otoliths from lake trout (Salvelinus namaycush) from the Chandler Lake system, Alaska (68.23°N, 152.70°W). All otoliths were collected in 1987 and exhibited highly synchronous patterns in growth-increment width. Increments were dated, the widths were measured, and age-related growth declines were removed using standard dendrochronology techniques. The detrended time series were averaged to generate an annually resolved chronology, which continuously spanned 1964–1984. The chronology positively and linearly correlated with August air temperature over the 22-year interval (p productivity. Given the broad distribution of lake trout within North America, this study suggests that otolith chronologies could be used to examine responses between freshwater ecosystems and environmental variability across a range of temporal and spatial scales.

  7. Detailed free span assessment for Mexilhao flow lines

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, Antonio; Franco, Luciano; Eigbe, Uwa; BomfimSilva, Carlos [INTECSEA, Houston, TX (United States); Escudero, Carlos [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil)

    2009-07-01

    The subsea gas production system of Mexilhao Field SPS-35, Santos Basin, offshore Brazil, is composed basically of two rigid 12.75 inches production flow lines approximately 21 km long installed in a fairly rough seabed. During the basic design, the free span assessment was performed considering the maximum allowable free span length determined by the response model proposed by DNV-RP-F105. This approach resulted in a large number of predicted free span requiring corrections, leading to a higher capital cost for the project. In this sense, a detailed free span VIV fatigue assessment was proposed, considering multi-spans and multi-mode effects and also the post lay survey data. The assessment followed the DNV-RP-F105 recommendations for multi-spans and multi-mode effects, using Finite Element Analysis to determine the natural frequencies, mode shapes and corresponding stresses associated with the mode shapes. The assessment was performed in three stages, the first during the detailed design as part of the bottom roughness analysis using the expected residual pipelay tension. The second stage was performed after pipelay, considering the post-lay survey data, where the actual requirements for span correction were determined. Actual pipelay tension was used and seabed soil stiffness adjusted in the model to match the as-laid pipeline profile obtained from the survey data. The first and second stage assessments are seamlessly automated to speed up the evaluation process and allow for quick response in the field, which was important to keep the construction vessel time minimized. The third stage was performed once the corrections of the spans were made and the purpose was to confirm that the new pipeline configuration along the supported spans had sufficient fatigue life for the temporary and operational phases. For the assessment of all three stages, the probability of occurrence and directionality of the near bottom current was considered to improve prediction of the

  8. Leaf life span and nitrogen content in semideciduous forest tree species (Croton priscus and Hymenaea courbaril Duração da vida da folha e conteúdo de nitrogênio em espécies arbóreas (Croton priscus e Hymenaea courbaril de floresta semidecídua

    Directory of Open Access Journals (Sweden)

    Claudia Regina Baptista Haddad

    2004-01-01

    Full Text Available In comparison to deciduous species, evergreen plants have lower leaf nutrient contents and higher leaf life span, important mechanisms for nutrient economy, allowing the colonization of low fertility soils. Strategies to conserve nitrogen in two semideciduous tropical forest tree species, with different leaf life spans were analyzed. The hypothesis was the fact that the two species would present different nitrogen conservation mechanisms in relation to chemical (total nitrogen, protein, chlorophyll, and proteolytic activity, functional (leaf life span, N-use efficiency, and N-resorption efficiency, morphological (specific leaf mass leaf characteristics, and total nitrogen in the soil. Hymenaea courbaril L. presented lower nitrogen compounds in leaves, longer leaf life span, higher N-use efficiency, and higher specific leaf mass, while absorbing proportionally less nitrogen from the soil than Croton priscus Croizat. These characteristics can contribute for a better nitrogen economy strategy of H. courbaril. No relationship was found between leaf life span and N resorption efficiency, nor between leaf life span, protease activity and nitrogen mobilization. The electrophoretic profiles of proteolytic enzymes in young leaves of the two species presented more bands with enzymatic activity than other kinds of leaves.Comparadas a espécies decíduas, as sempre-verdes têm menos nutrientes nas folhas, que também são mais longevas. Estes mecanismos são importantes para economia de nutrientes, e permitem a colonização de solos com baixa fertilidade. Foram analisadas estratégias de conservação de nitrogênio em duas espécies de floresta semidecídua, que aparentemente apresentavam longevidades foliares diferentes. Para isto foram comparados mecanismos químicos (concentrações de nitrogênio total, de proteína e clorofila e atividade proteolítica, funcionais (duração de vida das folhas, eficiência do uso de nitrogênio e eficiência de

  9. Criticism of traditional chronology: How long will Scaliger survive?

    Directory of Open Access Journals (Sweden)

    Bukvić Rajko

    2005-01-01

    Full Text Available The paper considers the problems of current state and survival of traditional chronology and history based upon the Scaliger and Petavius books from XVI and XVII centuries. Among many approaches that insist on the need of examination of that chronology, developed at first in Russia, but also in Germany, England, USA and other countries, author focuses to the investigation of Fomenko and his collaborators, but also the Khronotron group. Both these groups, like many others critics of current chronology, as their inspirators and predecessors mark Newton and Morozov, two great scientists who during many decades (! intensively considered problems of examination of chronology and history.

  10. Perceived Changes in Well-Being: The Role of Chronological Age, Target Age, and Type of Measure

    Science.gov (United States)

    Okun, Morris A.; Dittburner, Julie L.; Huff, Barbara P.

    2006-01-01

    The goal of this study is to investigate whether perceived changes in one's well-being from the present to the future are related to chronological age, target age, and type of measure (psychological well-being versus life satisfaction). Young adults (N = 114) rated their current well-being and their future well-being at one of three target ages…

  11. 亚硝酸钠对果蝇寿命和生育力影响及维生素C对其拮抗作用研究%The Effect of Sodium Nitrite on Life-span and Reproductive Capacity of Drosophila melanogaster and Antagonism of Vc on Sodium Nitrite

    Institute of Scientific and Technical Information of China (English)

    张书玲; 董丽军; 王瑞强

    2011-01-01

    In this study, Drosophila melanogaster was used as the experimental animal to study the effects of sodium nitrite on life-span, reproductive capacity and antagonism of Vc on sodium nitrite. The results showed that the life-span, average longest and average shortest life-span was shortened in sodium nitrite. Compared with the control group, the average life-span of D. melanogaster was shortened in sodium nitrite significantly (P<0.05 or P<0.01) except for 30 mg/mL sodium nitrite experimental group. The reproductive capacity of D. melanogaster reduced in sodium nitrite significantly (P<0.01). When the concentration of Vc were 0.13%,0.40% and 1.20% in the 480 mg/mL sodium nitrite Medium, with the concentration of Vc increased, the average life span of D. melanogaster was prolonged significantly(P<0.05 or P<0.01) except for 0.13% Vc experimental group of male D. melanogaster. The reproductive capacity of D. melanogaster was increased significantly (P<0.01) in 0.40% and 1.20% Vc experimental group.%以黑腹果(Drosophila melanogaster)为试验动物,研究了亚硝酸钠对果蝇寿命和生育力的影响及维生素C(Vc)对其拮抗作用.结果表明:培养基中添加亚硝酸钠可以显著缩短果蝇的平均寿命、最短和最长平均寿命.与对照组相比,除30mg/mL亚硝酸钠处理组的雄果蝇差异不显著外,其他实验组果蝇平均寿命均显著或极显著缩短(P<0.05或P<0.01).果蝇的生育力也随着亚硝酸钠浓度的升高而降低,各实验组与对照相比差异均达到极显著水平(P<0.01).随后在含480mg/mL亚硝酸钠的培养基中加入不同浓度Vc,结果发现,除雄果蝇的0.13%实验组与对照差异不显著外,其他各组雌、雄果蝇的平均寿命随Vc浓度的提高而显著或极显著延长(P<0.05或P<0.01).同样,Vc浓度为0.40%和1.20%实验组果蝇生育力亦极显著高于对照组.

  12. Time and Chronology: Conjoined Twins or Distant Cousins?

    Science.gov (United States)

    Blow, Frances; Lee, Peter; Shemilt, Denis

    2012-01-01

    Weaknesses in pupils' grasp of historical chronology are a commonplace in popular discussion of the state of history education. However, as Blow, Lee and Shemilt argue, although undoubtedly necessary and fundamental, mastery of chronological conventions is not sufficient: the difficulties that pupils experience when learning history are…

  13. Cell-autonomous mechanisms of chronological aging in the yeast Saccharomyces cerevisiae

    Directory of Open Access Journals (Sweden)

    Anthony Arlia-Ciommo

    2014-05-01

    Full Text Available A body of evidence supports the view that the signaling pathways governing cellular aging – as well as mechanisms of their modulation by longevity-extending genetic, dietary and pharmacological interventions - are conserved across species. The scope of this review is to critically analyze recent advances in our understanding of cell-autonomous mechanisms of chronological aging in the budding yeast Saccharomyces cerevisiae. Based on our analysis, we propose a concept of a biomolecular network underlying the chronology of cellular aging in yeast. The concept posits that such network progresses through a series of lifespan checkpoints. At each of these checkpoints, the intracellular concentrations of some key intermediates and products of certain metabolic pathways - as well as the rates of coordinated flow of such metabolites within an intricate network of intercompartmental communications - are monitored by some checkpoint-specific ′′master regulator′′ proteins. The concept envisions that a synergistic action of these master regulator proteins at certain early-life and late-life checkpoints modulates the rates and efficiencies of progression of such processes as cell metabolism, growth, proliferation, stress resistance, macromolecular homeostasis, survival and death. The concept predicts that, by modulating these vital cellular processes throughout lifespan (i.e., prior to an arrest of cell growth and division, and following such arrest, the checkpoint-specific master regulator proteins orchestrate the development and maintenance of a pro- or anti-aging cellular pattern and, thus, define longevity of chronologically aging yeast.

  14. Chronology of petroleum geophysics; Sekiyu butsuri tansa nenpyo

    Energy Technology Data Exchange (ETDEWEB)

    Kametani, T.

    1996-10-01

    A table, chronology of petroleum geophysics in overseas and in Japan, has been prepared for the convenience of checking events, which are thought to be important as notable affairs in application, success, and technical innovation. In overseas, successes in the 1920s were remarkable, when the US modern geophysical exploration made a start. Successes in determining the position of exploratory drilling by means of the gravity torsion balance, fan shooting seismic refraction method, and seismic reflection method occurred one after another. The USA has kept its situation stably as the number one by the seismic reflection method occurred most lately, and its life has been further elongated by adopting digital techniques. The CDP technique which became to be used simultaneously, and the seismic sources without using explosives, such as vibro-seismic source and air gun, extended the success of digital techniques drastically. In the future, the progress of 3-D exploration technology is expected. In Japan, about 18 years lag in the seismic reflection method is observed when compared with the USA. Japan has provided leading techniques in the shallow layer seismic reflection method and S-wave exploration. 40 refs., 1 tab.

  15. Chronology of Lake El'gygytgyn sediments

    Directory of Open Access Journals (Sweden)

    N. R. Nowaczyk

    2013-06-01

    Full Text Available A 318 m long sedimentary profile drilled by the International Continental Scientific Drilling Program (ICDP at Site 5011-1 in Lake El'gygytgyn, Far East Russian Arctic, has been analysed for its sedimentologic response to global climate modes by chrono-stratigraphic methods. The 12 km wide lake is sited in an 18 km large crater that was created by the impact of a meteorite 3.58 Ma ago. Since then sediments have been continuously deposited. For establishing their chronology, major reversals of the Earth's magnetic field provided initial tie points for the age model, confirming that the impact occurred in the earliest Gauss chron. Various stratigraphic parameters, reflecting redox conditions at the lake floor and climatic conditions in the catchment were tuned synchronously to Northern Hemisphere insolation variations and the marine oxygen isotope stack, respectively. Thus, a robust age model comprising more than 600 tie points could be defined. It could be shown that deposition of sediments in Lake El'gygytgyn occurred in concert with global climatic cycles. The upper ~160 m of sediments represent the past 3.3 Ma, equivalent to sedimentation rates of 4 to 5 cm ka−1, whereas the lower 160 m represent just the first 0.3 Ma after the impact, equivalent to sedimentation rates in the order of 45 cm ka−1.

  16. 铅和维生素C染毒对果蝇寿命和生殖力以及抗氧化系统的影响%Effects of Lead and Vitamin C on Fecundity, Life Span and Antioxidant System of Drosophila melanogaster

    Institute of Scientific and Technical Information of China (English)

    朱姝; 吴雨龙; 张边江

    2011-01-01

    Objective To study the combined effect of lead and vitamin C (VC) on the life span,the fecundity and antioxidant system of the Drosophila melanirogaster. Methods The males and virgin females of Drosophila melanrogaster were divided randomly into ten groups and were fed with lead medium at different concentrations (0,200,300,400 and 500 mg/L). And the Drosophila melanrogaster were also treated by 150 mg/L VC medium with the above concentrations of lead. The life span and the fecundity of Drosophila melanrogaster were recorded and the superoxide dismutase (SOD) activity and malondialdehyde (MDA) contents were determined. Results Compared with the control,the life span was significantly(P0.05). At 300 mg/L of lead with 150 mg/L VC, the first filial of Drosophila melanrogaster increased and was close to that in the control (P>0.05) ,the increase of SOD activity and the decrease of MDA contents were still significant different from that in the control. These indicated VC had certain antagonistic effect on the toxicity of lead. Conclusion High lead exposure has an obvious adverse effect on the fecundity,the life span and antioxidant system in Drosophila melanrogaster and vitamin C can relieve the toxicity.%目的 研究铅和维生素C(VC)染毒对野生型果蝇(Drosophila melanrogaster)寿命、生育力以及抗氧化系统的影响.方法 将8d内羽化且未交配的野生型红眼长翅果蝇随机分为10组,分别为对照(普通培养基)组和200、300、400、500 mg/L乙酸铅染毒组以及0、200、300、400、500 mg/L乙酸铅+150 mg/L VC染毒组,果蝇可自由摄食含上述物质的培养基.测定果蝇的寿命、子代数量及匀浆中SOD活力和MDA含量.结果 随着铅染毒浓度的升高,果蝇体内MDA含量呈上升趋势,生殖力和体内SOD活力呈下降趋势,寿命逐渐缩短.添加VC后,果蝇体内MDA含量有所下降,生殖力和体内SOD活力有所上升,寿命有所延长.结论 铅对果蝇的寿命和生殖力以及抗氧化

  17. Prospects for Chronological Studies of Martian Rocks and Soils

    Science.gov (United States)

    Nyquist, L. E.; Shih, C-Y.; Reese, Y. D.

    2008-01-01

    Chronological information about Martian processes comes from two sources: Crater-frequency studies and laboratory studies of Martian meteorites. Each has limitations that could be overcome by studies of returned Martian rocks and soils. Chronology of Martian volcanism: The currently accepted chronology of Martian volcanic surfaces relies on crater counts for different Martian stratigraphic units [1]. However, there is a large inherent uncertainty for intermediate ages near 2 Ga ago. The effect of differing preferences for Martian cratering chronologies [1] is shown in Fig. 1. Stoeffler and Ryder [2] summarized lunar chronology, upon which Martian cratering chronology is based. Fig. 2 shows a curve fit to their data, and compares to it a corresponding lunar curve from [3]. The radiometric ages of some lunar and Martian meteorites as well as the crater-count delimiters for Martian epochs [4] also are shown for comparison to the craterfrequency curves. Scaling the Stoeffler-Ryder curve by a Mars/Moon factor of 1.55 [5] places Martian shergottite ages into the Early Amazonian to late Hesperian epochs, whereas using the lunar curve of [3] and a Mars/Moon factor 1 consigns the shergottites to the Middle-to-Late Amazonian, a less probable result. The problem is worsened if a continually decreasing cratering rate since 3 Ga ago is accepted [6]. We prefer the adjusted St ffler-Ryder curve because it gives better agreement with the meteorite ages (Fig.

  18. Gamma spectrometry for chronology of recent sediments

    Energy Technology Data Exchange (ETDEWEB)

    Pittauerova, Daniela

    2013-12-17

    This thesis deals with several aspects of gamma spectrometric analysis of natural and artificial isotopes in sediments and their use as tracers for qualification and quantification of accumulation and mixing processes in different aquatic environments. Sediment cores from three distinct areas including terrigenous sediments deposited on the continental slope off NW Africa, deep sea sediments off Sumba Island and five stations from the Gulf of Eilat in the Red Sea area were measured and interpreted within this dissertation. The main concern in gamma spectrometry of voluminous environmental samples is a reliable efficiency calibration. This is specially relevant for the analysis of low energy gamma emitters (<100 keV). {sup 210}Pb, an important isotopic tracer to cover the period of the last century, is one of them. Within this work mathematical efficiency calibration was applied using a commercial software package. A series of validation tests was performed and evaluated for point and voluminous samples. When using {sup 210}Pb as a tracer it is necessary to determine its excess portion, which is not supported by ingrowth from the parent nuclide {sup 226}Ra. Its analysis is mostly performed via short lived daughter isotopes that follow after the intermediate gaseous member {sup 222}Rn. Preventing the escape of radon from the sample is a critical step before analysis due to a negative effect of supported {sup 210}Pb underestimation on the chronology, which was also documented in this thesis. Time series registering ingrowth of {sup 214}Pb and {sup 214}Bi towards radioactive equilibrium with {sup 226}Ra in different containers were evaluated for analyses of {sup 226}Ra. Direct analyses of {sup 226}Ra was compared to its detection via daughter products. A method for aligning parallel radionuclide depth profiles was described and applied successfully in two case studies from the continental slope off NW Africa and off Sumba Island, Indonesia. This is primarily important

  19. Establishing Denudation Chronology through Weathering Geochronology

    Science.gov (United States)

    Riffel, S. B.; Vasconcelos, P. M.; Farley, K. A.; Carmo, I. O.

    2011-12-01

    Planar landforms - erosion surfaces - are used as temporal markers in denudation chronology. These surfaces are interpreted as the result of long-term weathering and denudation controlled by a specific base level within a given time-interval characterized by long-term tectonic stability. The presence of several planar landforms at distinct elevations is interpreted as evidence for distinct denudation events, separated by periods of tectonic reactivation and crustal uplift. We selected an area in the Paraná-La Plata basin, southern Brazil (25°S lat.) to investigate if the application of weathering geochronology by the 40Ar/39Ar and (U-Th)/He methods could permit differentiating different elevation landsurfaces. We dated supergene Mn oxyhydroxides by 40Ar/39Ar geochronology and coexisting supergene Fe oxyhydroxides by the (U-Th)/He method from one of the three regional landsurfaces - The First, Second, and Third Paraná plateaus - previously identified in this area. Two sites were sampled from the Second Paraná Plateau: a ferricrust at Serra das Almas (7 hand specimens of goethite at 1080 m of altitude) and deeply weathered ferricretes and saprolites at Vila Velha (11 hand specimens of cryptomelane and 14 of goethite at 910 m of altitude). The Serra das Almas sites hosts a stratified weathering profile with ferricrust, and mottle zone. The Vila Velha site results from intense weathering that led to the precipitation of well-crystallized supergene minerals precipitated within fractures in the saprolites. The geochronological results are correlatable between the two sites and the two distinct methods (40Ar/39Ar and (U-Th)/He), and they reveal three generations of weathering and mineral precipitation: Late Eocene-Oligocene, Early Miocene, and Pleistocene. The geochronological results suggested that the Second Paraná Plateau formed by regional erosion during the Oligocene, and that this landsurface has been continuously exposed to weathering and erosion since then

  20. Chronological development avenues in biotechnology across the world

    Directory of Open Access Journals (Sweden)

    Prashant Y Mali

    2011-01-01

    Full Text Available Biotechnology is expected to be a great technological revolution followed by information technology. It is an application of scientific and engineering principles to the processing of material by biological agents to provide better goods and services to mankind. Commercially its techniques are applied long back in 6 th century in the art of brewing, wine making and baking. It has progressed there after crossing different land marks. Modern biotechnology has developed significantly in the late 19 th century with groundbreaking discoveries applicable in medicine, food, agriculture, chemistry, environmental protection and many more industries. It is widely used in the development of high-yielding, disease-resistant, better quality varieties by applying tissue culture and recombinant DNA techniques. It has wide application in animal breeding using techniques such as artificial insemination, in vitro fertilization and embryo transfer. Specific enzymes used in laundry, fuel and leather industries for better quality, economically feasible and environmental friendly production. Biotechnology in healthcare system uses body′s own tools and weapons to fight against diseases, manufacturing of targeted therapeutic proteins, gene therapy and so on. Novel approaches such as proteomics and structural biology are contributing to understanding the chemistry of life and diseases. Malfunctioning gene replaced with correctly functioning gene by using gene therapy. Tissue engineering has opened up the use of in vitro developed tissue or organ in repairing wounded tissue and system biology which is a computer-based approach to understand cell functions. Although every new discovery related to biology and its implications is significant and has taken the technology ahead. This includes applications, commercialization, controversies, media exposure and so on. Hence, we have enlisted some of the chronological development avenues in biotechnology across the world.

  1. The History of Therapeutic Aerosols: A Chronological Review

    Science.gov (United States)

    Thiel, Charles G.

    2017-01-01

    Abstract In 1956, Riker Laboratories, Inc., (now 3 M Drug Delivery Systems) introduced the first pressurized metered dose inhaler (MDI). In many respects, the introduction of the MDI marked the beginning of the modern pharmaceutical aerosol industry. The MDI was the first truly portable and convenient inhaler that effectively delivered drug to the lung and quickly gained widespread acceptance. Since 1956, the pharmaceutical aerosol industry has experienced dramatic growth. The signing of the Montreal Protocol in 1987 led to a surge in innovation that resulted in the diversification of inhaler technologies with significantly enhanced delivery efficiency, including modern MDIs, dry powder inhalers, and nebulizer systems. The innovative inhalers and drugs discovered by the pharmaceutical aerosol industry, particularly since 1956, have improved the quality of life of literally hundreds of millions of people. Yet, the delivery of therapeutic aerosols has a surprisingly rich history dating back more than 3500 years to ancient Egypt. The delivery of atropine and related compounds has been a crucial inhalation therapy throughout this period and the delivery of associated structural analogs remains an important therapy today. Over the centuries, discoveries from many cultures have advanced the delivery of therapeutic aerosols. For thousands of years, therapeutic aerosols were prepared by the patient or a physician with direct oversight of the patient using custom-made delivery systems. However, starting with the Industrial Revolution, advancements in manufacturing resulted in the bulk production of therapeutic aerosol delivery systems produced by people completely disconnected from contact with the patient. This trend continued and accelerated in the 20th century with the mass commercialization of modern pharmaceutical inhaler products. In this article, we will provide a summary of therapeutic aerosol delivery from ancient times to the present along with a look to the

  2. Nitrogen availability, leaf life span and nitrogen conservation mechanisms in leaves of tropical trees Disponibilidade de nitrogênio, longevidade foliar e mecanismos de conservação de nitrogênio em folhas de espécies arbóreas tropicais

    Directory of Open Access Journals (Sweden)

    Guilherme Nascimento Corte

    2009-12-01

    Full Text Available Evergreen species of temperate regions are dominant in low-nutrient soils. This feature is attributed to more efficient mechanisms of nutrient economy. Nevertheless, the cashew (Anacardium occidentale- Anacardiaceae, a deciduous species, is native to regions in Brazil with sandy soil, whilst the annatto (Bixa orellana- Bixaceae, classified as an evergreen species native to tropical America, grows spontaneously in regions with more humid soils. Evergreens contain robust leaves that can resist adverse conditions for longer. The physical aspects of the leaves and mechanisms of nutrient economy between the two species were compared, in order to verify whether the deciduous species had more efficient mechanisms that might explain its occurrence in regions of low soil fertility. The mechanisms of nitrogen economy were also compared for the two species at available concentrations of this nutrient. The following were analysed: (i leaf life span, (ii physical leaf characteristics (leaf mass per area, and rupture strain, (iii nitrogenous compounds (nitrogen, chlorophyll, and protein, (iv nitrogen conservation mechanisms (nitrogen resorption efficiency, resorption proficiency, and use efficiency, and (v nitrogen conservation mechanisms under different availability of this mineral. The higher values of leaf mass per area and leaf rupture strain found in A. occidentale were related to its longer leaf life span. A. occidentale showed lower concentrations of nitrogen and protein in the leaves than B. orellana. Under lower nitrogen availability, A. occidentale had higher nitrogen resorption proficiency, nitrogen use efficiency and leaf life span than B. orellana. These characteristics may contribute to the adaptation of this species to sandy soils with low nitrogen content.Perenifólias de clima temperado são dominantes em solos pouco férteis. Essa característica é atribuída a mecanismos mais eficientes de economia de nutrientes. O cajueiro (Anacardium

  3. Online dating across the life span: Users' relationship goals.

    Science.gov (United States)

    Menkin, Josephine A; Robles, Theodore F; Wiley, Joshua F; Gonzaga, Gian C

    2015-12-01

    Utilizing data from an eHarmony.com relationship questionnaire completed by new users (N = 5,434), this study identifies prioritized goals in new romantic relationships and whether importance of these goals differs by participants' age and gender. Overall, users valued interpersonal communication more than sex appeal. Older users rated sexual attraction as slightly less important than younger users did, but they still highly valued the goal. Women placed even greater emphasis on communication over sexual attraction compared to men. However, although men valued sexual attraction more than women at all ages, only the youngest women valued interpersonal communication more than young men.

  4. Nutrition research to affect food and a healthy life span.

    Science.gov (United States)

    Ohlhorst, Sarah D; Russell, Robert; Bier, Dennis; Klurfeld, David M; Li, Zhaoping; Mein, Jonathan R; Milner, John; Ross, A Catharine; Stover, Patrick; Konopka, Emily

    2013-08-01

    Proper nutrition offers one of the most effective and least costly ways to decrease the burden of many diseases and their associated risk factors, including obesity. Nutrition research holds the key to increasing our understanding of the causes of obesity and its related comorbidities and thus holds promise to markedly influence global health and economies. After outreach to 75 thought leaders, the American Society for Nutrition (ASN) convened a Working Group to identify the nutrition research needs whose advancement will have the greatest projected impact on the future health and well-being of global populations. ASN's Nutrition Research Needs focus on the following high priority areas: 1) variability in individual responses to diet and foods; 2) healthy growth, development, and reproduction; 3) health maintenance; 4) medical management; 5) nutrition-related behaviors; and 6) food supply/environment. ASN hopes the Nutrition Research Needs will prompt collaboration among scientists across all disciplines to advance this challenging research agenda given the high potential for translation and impact on public health. Furthermore, ASN hopes the findings from the Nutrition Research Needs will stimulate the development and adoption of new and innovative strategies that can be applied toward the prevention and treatment of nutrition-related diseases. The multidisciplinary nature of nutrition research requires stakeholders with differing areas of expertise to collaborate on multifaceted approaches to establish the evidence-based nutrition guidance and policies that will lead to better health for the global population. In addition to the identified research needs, ASN also identified 5 tools that are critical to the advancement of the Nutrition Research Needs: 1) omics, 2) bioinformatics, 3) databases, 4) biomarkers, and 5) cost-effectiveness analysis.

  5. Emotional Egocentricity Bias across the life-span

    OpenAIRE

    2016-01-01

    In our daily lives, we often have to quickly estimate the emotions of our conspecifics in order to have successful social interactions. While this estimation process seems quite easy when we are ourselves in a neutral or equivalent emotional state, it has recently been shown that in case of incongruent emotional states between ourselves and the others, our judgments can be biased. This phenomenon, introduced to the literature with the term Emotional Egocentricity Bias (EEB), has been found to...

  6. Emotional Egocentricity Bias Across the Life-Span

    OpenAIRE

    2016-01-01

    In our daily lives, we often have to quickly estimate the emotions of our conspecifics in order to have successful social interactions. While this estimation process seems quite easy when we are ourselves in a neutral or equivalent emotional state, it has recently been shown that in case of incongruent emotional states between ourselves and the others, our judgments can be biased. This phenomenon, introduced to the literature with the term Emotional Egocentricity Bias (EEB), has been found to...

  7. Emotion recognition in music changes across the adult life span.

    Science.gov (United States)

    Lima, Cesar F; Castro, Sao Luis

    2011-06-01

    In comparison with other modalities, the recognition of emotion in music has received little attention. An unexplored question is whether and how emotion recognition in music changes as a function of ageing. In the present study, healthy adults aged between 17 and 84 years (N=114) judged the magnitude to which a set of musical excerpts (Vieillard et al., 2008) expressed happiness, peacefulness, sadness and fear/threat. The results revealed emotion-specific age-related changes: advancing age was associated with a gradual decrease in responsiveness to sad and scary music from middle age onwards, whereas the recognition of happiness and peacefulness, both positive emotional qualities, remained stable from young adulthood to older age. Additionally, the number of years of music training was associated with more accurate categorisation of the musical emotions examined here. We argue that these findings are consistent with two accounts on how ageing might influence the recognition of emotions: motivational changes towards positivity and, to a lesser extent, selective neuropsychological decline.

  8. Patterns of Learning. New Perspectives on Life-Span Education.

    Science.gov (United States)

    Houle, Cyril O.

    Basic methods of learning, most of which have been used through centuries of recorded thought, are discussed, along with learning as a lifelong process, and ways to enhance and diversify modern education. Numerous learning processes are studied by examining the lives of great individuals who have exemplified innovative and multifaceted approaches…

  9. Neurological phenotypes for Down syndrome across the life span

    OpenAIRE

    2012-01-01

    This chapter reviews the neurological phenotype of Down syndrome (DS) in early development, childhood, and aging. Neuroanatomic abnormalities in DS are manifested as aberrations in gross brain structure as well as characteristic microdysgenetic changes. As the result of these morphological abnormalities, brain circuitry is impaired. While an intellectual disability is ubiquitous in DS, there is a wide range of variation in cognitive performance and a growing understanding between aberrant bra...

  10. Assessing Executive Functions: A Life-Span Perspective

    Science.gov (United States)

    Reynolds, Cecil R.; Horton, Arthur MacNeill, Jr.

    2008-01-01

    Despite many disagreements on the utility of neuropsychological applications in schools, executive function measures have been found to be useful across a variety of areas and ages. In addition, many disagreements are extant in discussions of the maturational course of the development of executive functioning abilities that are dependent on…

  11. Stressful Jobs with Little Control/Shorter Life Spans?

    Science.gov (United States)

    ... done." The study was published recently in Personnel Psychology . SOURCES: Erik Gonzalez-Mule, Ph.D., assistant professor, organizational behavior and human resources, Indiana University's Kelley School of Business, Bloomington; Nellie Brown, M.S., director, Workplace Health and ...

  12. Meditation improves self-regulation over the life span.

    Science.gov (United States)

    Tang, Yi-Yuan; Posner, Michael I; Rothbart, Mary K

    2014-01-01

    The use of meditation to improve emotion and attention regulation has a long history in Asia and there are many practitioners in Western countries. Much of the evidence on the effectiveness of meditation is either anecdotal or a comparison of long-term meditators with controls matched in age and health. Recently, it has been possible to establish changes in self-regulation in undergraduate students after only 5 days of meditation practice, allowing randomized trials comparing effects of meditation with other self-control methods such as relaxation training. Early studies took place in Chinese universities; however, similar effects have been obtained with U.S. undergraduates, and with Chinese children aged 4.5 years and older Chinese participants aged 65 years. Studies using neuroimaging techniques have shown that meditation improves activation and connectivity in brain areas related to self-regulation, and these findings may provide an opportunity to examine remediation of mental disorders in a new light.

  13. Nature over nurture: temperament, personality, and life span development.

    Science.gov (United States)

    McCrae, R R; Costa, P T; Ostendorf, F; Angleitner, A; Hrebícková, M; Avia, M D; Sanz, J; Sánchez-Bernardos, M L; Kusdil, M E; Woodfield, R; Saunders, P R; Smith, P B

    2000-01-01

    Temperaments are often regarded as biologically based psychological tendencies with intrinsic paths of development. It is argued that this definition applies to the personality traits of the five-factor model. Evidence for the endogenous nature of traits is summarized from studies of behavior genetics, parent-child relations, personality structure, animal personality, and the longitudinal stability of individual differences. New evidence for intrinsic maturation is offered from analyses of NEO Five-Factor Inventory scores for men and women age 14 and over in German, British, Spanish, Czech, and Turkish samples (N = 5,085). These data support strong conceptual links to child temperament despite modest empirical associations. The intrinsic maturation of personality is complemented by the culturally conditioned development of characteristic adaptations that express personality; interventions in human development are best addressed to these.

  14. A hierarchical causal taxonomy of psychopathology across the life span.

    Science.gov (United States)

    Lahey, Benjamin B; Krueger, Robert F; Rathouz, Paul J; Waldman, Irwin D; Zald, David H

    2017-02-01

    We propose a taxonomy of psychopathology based on patterns of shared causal influences identified in a review of multivariate behavior genetic studies that distinguish genetic and environmental influences that are either common to multiple dimensions of psychopathology or unique to each dimension. At the phenotypic level, first-order dimensions are defined by correlations among symptoms; correlations among first-order dimensions similarly define higher-order domains (e.g., internalizing or externalizing psychopathology). We hypothesize that the robust phenotypic correlations among first-order dimensions reflect a hierarchy of increasingly specific etiologic influences. Some nonspecific etiologic factors increase risk for all first-order dimensions of psychopathology to varying degrees through a general factor of psychopathology. Other nonspecific etiologic factors increase risk only for all first-order dimensions within a more specific higher-order domain. Furthermore, each first-order dimension has its own unique causal influences. Genetic and environmental influences common to family members tend to be nonspecific, whereas environmental influences unique to each individual are more dimension-specific. We posit that these causal influences on psychopathology are moderated by sex and developmental processes. This causal taxonomy also provides a novel framework for understanding the heterogeneity of each first-order dimension: Different persons exhibiting similar symptoms may be influenced by different combinations of etiologic influences from each of the 3 levels of the etiologic hierarchy. Furthermore, we relate the proposed causal taxonomy to transdimensional psychobiological processes, which also impact the heterogeneity of each psychopathology dimension. This causal taxonomy implies the need for changes in strategies for studying the etiology, psychobiology, prevention, and treatment of psychopathology. (PsycINFO Database Record

  15. Spans in 2-Categories: A monoidal tricategory

    CERN Document Server

    Hoffnung, Alexander E

    2011-01-01

    We present Trimble's definition of a tetracategory and prove that the spans in (strict) 2-categories with certain limits have the structure of a monoidal tricategory, defined as a one-object tetracategory. We recall some notions of limits in 2-categories for use in the construction of the monoidal tricategory of spans.

  16. Node degree distribution in spanning trees

    Science.gov (United States)

    Pozrikidis, C.

    2016-03-01

    A method is presented for computing the number of spanning trees involving one link or a specified group of links, and excluding another link or a specified group of links, in a network described by a simple graph in terms of derivatives of the spanning-tree generating function defined with respect to the eigenvalues of the Kirchhoff (weighted Laplacian) matrix. The method is applied to deduce the node degree distribution in a complete or randomized set of spanning trees of an arbitrary network. An important feature of the proposed method is that the explicit construction of spanning trees is not required. It is shown that the node degree distribution in the spanning trees of the complete network is described by the binomial distribution. Numerical results are presented for the node degree distribution in square, triangular, and honeycomb lattices.

  17. Ancient Egyptian chronology and the astronomical orientation of pyramids

    Science.gov (United States)

    Spence, Kate

    2000-11-01

    The ancient Egyptian pyramids at Giza have never been accurately dated, although we know that they were built approximately around the middle of the third millennium BC. The chronologies of this period have been reconstructed from surviving lists of kings and the lengths of their reigns, but the lists are rare, seldom complete and contain known inconsistencies and errors. As a result, the existing chronologies for that period (the Old Kingdom) can be considered accurate only to about +/-100 years, a figure that radiocarbon dating cannot at present improve. Here I use trends in the orientation of Old Kingdom pyramids to demonstrate that the Egyptians aligned them to north by using the simultaneous transit of two circumpolar stars. Modelling the precession of these stars yields a date for the start of construction of the Great Pyramid that is accurate to +/-5 yr, thereby providing an anchor for the Old Kingdom chronologies.

  18. Resveratrol Effects on Life Span and Fertility of Caenorhabditis Elegans Subject to 60Co Gamma Ray Irradiation%白藜芦醇对60Coγ射线照射线虫寿命和生殖的影响

    Institute of Scientific and Technical Information of China (English)

    叶侃; 季晨博; 郭锡熔; 古桂雄

    2011-01-01

    Caenorhabditis elegans was used as experimental model to investigate radiation effect of resveratol on caenorhabdities elegans irradiated by 60Co γray. Treatment with resveratrol can increase average life span and spawning rate, improve the surrival rate of eggs, and protect their mitochondrion function of cacnorhabdities elegans exposure to 60Co rr ray. The results indicate that resveratrol has radiation protection effects, which might be related to its action on ROS decrease and mitochondrial defend.%以线虫作为实验模型,观察白藜芦醇(RES)对受60Coγ射线照射线虫的保护作用.结果表明,白藜芦醇能提高受照射线虫的寿命,增加产卵率,提高卵的存活率,保护其线粒体功能.其作用机制可能与白藜芦醇减轻氧自由基所致的线虫线粒体损伤有关.

  19. Chronology and Sources of Lunar Impact Bombardment

    CERN Document Server

    Ćuk, Matija

    2011-01-01

    The Moon has suffered intense impact bombardment ending at 3.9 Gyr ago, and this bombardment probably affected all of the inner Solar System. Basin magnetization signatures and lunar crater size-distributions indicate that the last episode of bombardment at about 3.85 Gyr ago was less extensive than previously thought. We explore the contribution of the primordial Mars-crosser population to early lunar bombardment. We find that Mars-crosser population initially decays with a 80-Myr half-life, with the long tail of survivors clustering on temporarily non-Mars-crossing orbits between 1.8 and 2 AU. These survivors decay with half-life of about 600 Myr and are progenitors of the extant Hungaria asteroid group in the same region. We estimate the primordial Mars-crosser population contained about 0.01-0.02 Earth masses. Such initial population is consistent with no lunar basins forming after 3.8 Gya and the amount of mass in the Hungaria group. As they survive longer and in greater numbers than other primordial pop...

  20. Signal Enhancement with Variable Span Linear Filters

    DEFF Research Database (Denmark)

    Benesty, Jacob; Christensen, Mads Græsbøll; Jensen, Jesper Rindom

    -to-noise ratio, Wiener, and tradeoff filters (including their new generalizations) can be obtained using the variable span filter framework. It then illustrates how the variable span filters can be applied in various contexts, namely in single-channel STFT-based enhancement, in multichannel enhancement in both......This book introduces readers to the novel concept of variable span speech enhancement filters, and demonstrates how it can be used for effective noise reduction in various ways. Further, the book provides the accompanying Matlab code, allowing readers to easily implement the main ideas discussed....... Variable span filters combine the ideas of optimal linear filters with those of subspace methods, as they involve the joint diagonalization of the correlation matrices of the desired signal and the noise. The book shows how some well-known filter designs, e.g. the minimum distortion, maximum signal...

  1. Signal enhancement with variable span linear filters

    CERN Document Server

    Benesty, Jacob; Jensen, Jesper R

    2016-01-01

    This book introduces readers to the novel concept of variable span speech enhancement filters, and demonstrates how it can be used for effective noise reduction in various ways. Further, the book provides the accompanying Matlab code, allowing readers to easily implement the main ideas discussed. Variable span filters combine the ideas of optimal linear filters with those of subspace methods, as they involve the joint diagonalization of the correlation matrices of the desired signal and the noise. The book shows how some well-known filter designs, e.g. the minimum distortion, maximum signal-to-noise ratio, Wiener, and tradeoff filters (including their new generalizations) can be obtained using the variable span filter framework. It then illustrates how the variable span filters can be applied in various contexts, namely in single-channel STFT-based enhancement, in multichannel enhancement in both the time and STFT domains, and, lastly, in time-domain binaural enhancement. In these contexts, the properties of ...

  2. Trees, Tight-Spans and Point Configuration

    CERN Document Server

    Herrmann, Sven

    2011-01-01

    Tight-spans of metrics were first introduced by Isbell in 1964 and rediscovered and studied by others, most notably by Dress who gave them this name. Subsequently, it was found that tight-spans could be defined for more general maps, such as directed metrics and distances, and more recently for diversities. In this paper, we show that all of these tight-spans can be defined in terms of point configurations. This provides a useful way in which to study these objects in a unified and systematic way. We also show that by using point configurations we can recover results concerning one-dimensional tight-spans for all of the maps we consider, as well as extend these and other results to more general maps such as symmetric and unsymmetric maps.

  3. Evaluating the efficiency of shortcut span protection

    DEFF Research Database (Denmark)

    Ruepp, Sarah Renée; Dittmann, Lars; Berger, Michael Stübert;

    2010-01-01

    This paper presents a comparison of various recovery methods in terms of capacity efficiency with the underlying aim of reducing control plane load. In particular, a method where recovery requests are bundled towards the destination (Shortcut Span Protection) is evaluated can compared against...... traditional recovery methods. The optimization model is presented and our simulation results show that Shortcut Span Protection uses more capacity than the unbundled related methods, but this is compensated by easier control and management of the recovery actions....

  4. Social network sampling using spanning trees

    Science.gov (United States)

    Jalali, Zeinab S.; Rezvanian, Alireza; Meybodi, Mohammad Reza

    2016-12-01

    Due to the large scales and limitations in accessing most online social networks, it is hard or infeasible to directly access them in a reasonable amount of time for studying and analysis. Hence, network sampling has emerged as a suitable technique to study and analyze real networks. The main goal of sampling online social networks is constructing a small scale sampled network which preserves the most important properties of the original network. In this paper, we propose two sampling algorithms for sampling online social networks using spanning trees. The first proposed sampling algorithm finds several spanning trees from randomly chosen starting nodes; then the edges in these spanning trees are ranked according to the number of times that each edge has appeared in the set of found spanning trees in the given network. The sampled network is then constructed as a sub-graph of the original network which contains a fraction of nodes that are incident on highly ranked edges. In order to avoid traversing the entire network, the second sampling algorithm is proposed using partial spanning trees. The second sampling algorithm is similar to the first algorithm except that it uses partial spanning trees. Several experiments are conducted to examine the performance of the proposed sampling algorithms on well-known real networks. The obtained results in comparison with other popular sampling methods demonstrate the efficiency of the proposed sampling algorithms in terms of Kolmogorov-Smirnov distance (KSD), skew divergence distance (SDD) and normalized distance (ND).

  5. A first chronology for the NEEM ice core

    Directory of Open Access Journals (Sweden)

    S. O. Rasmussen

    2013-05-01

    Full Text Available A stratigraphy-based chronology for the North Greenland Eemian Ice Drilling (NEEM ice core has been derived by transferring the annual layer counted Greenland Ice Core Chronology 2005 (GICC05 from the NGRIP core to the NEEM core using 787 match points of mainly volcanic origin identified in the Electrical Conductivity Measurement (ECM and Dielectrical Profiling (DEP records. Tephra horizons found in both the NEEM and NGRIP ice cores are used to test the matching based on ECM and DEP and provide additional horizons used for the time scale transfer. A thinning function reflecting the accumulated strain along the core has been determined using a Dansgaard–Johnsen flow model and an isotope-dependent accumulation rate parameterization. Flow parameters are determined from Monte Carlo analysis constrained by the observed depth-age horizons. In order to construct a chronology for the gas phase, the ice age–gas age difference (Δage has been reconstructed using a coupled firn densification–heat diffusion model. Temperature and accumulation inputs to the Δage model, initially derived from the water isotope proxies, have been adjusted to optimize the fit to timing constraints from δ15N of nitrogen and high-resolution methane data during the abrupt onsets of interstadials. The ice and gas chronologies and the corresponding thinning function represent the first chronology for the NEEM core, and based on both the flow and firn modelling results, the accumulation history for the NEEM site has been reconstructed, providing the necessary basis for further analysis of the records from NEEM.

  6. Chronology protection in stationary three-dimensional spacetimes

    CERN Document Server

    Raeymaekers, Joris

    2011-01-01

    We study chronology protection in stationary, rotationally symmetric spacetimes in 2+1 dimensional gravity, focusing especially on the case of negative cosmological constant. We show that in such spacetimes closed timelike curves must either run all the way to the boundary or, alternatively, the matter stress tensor must violate the null energy condition in the bulk. We also show that the matter in the closed timelike curve region gives a negative contribution to the conformal weight from the point of view of the dual conformal field theory. We illustrate these properties in a class of examples involving rotating dust in anti-de Sitter space, and comment on the use of the AdS/CFT correspondence to study chronology protection.

  7. A Survey of the Xia-Shang-Zhou Chronology Project

    Institute of Scientific and Technical Information of China (English)

    Xi Zezong

    2002-01-01

    @@ Ⅰ. Goals In connection with the history of science, the XiaShang-Zhou Chronology Project is one of the important projects of the National Key Science and Technology Research and Development Programme of the Ninth Five-Year Plan. It officially began in May 1996.After five years of effort by more than 200 scholars and experts from the Chinese Academy of Sciences,the Chinese Academy of Social Sciences, Peking University and other institutions, the project has attained its goal. The general goal of the project is to establish a chronological table for the three dynasties by means of combining the humanities and social sciences with the natural sciences. The concrete goals for different historical periods are:

  8. Weight-Constrained Minimum Spanning Tree Problem

    OpenAIRE

    Henn, Sebastian Tobias

    2007-01-01

    In an undirected graph G we associate costs and weights to each edge. The weight-constrained minimum spanning tree problem is to find a spanning tree of total edge weight at most a given value W and minimum total costs under this restriction. In this thesis a literature overview on this NP-hard problem, theoretical properties concerning the convex hull and the Lagrangian relaxation are given. We present also some in- and exclusion-test for this problem. We apply a ranking algorithm and the me...

  9. The use of AMS radiocarbon dating for Xia-Shang-Zhou chronology

    CERN Document Server

    Guo, Z Y; LiuKeXin; Lu Xiang Yang; Ma Hong Ji; Wu Xiao Hon; Yuan Si Xun

    2000-01-01

    The possibility and problems of using radiocarbon dating to historical chronology are discussed. The current situation of ancient Chinese chronology and the project of Xia-Shang-Zhou chronology are introduced. A chronological study requires the AMS radiocarbon dating with high precision, high reliability and high efficiency. The Peking University AMS facility (PKUAMS) has been upgraded and a series of quality control steps were adopted. To reduce the error of calendar age, wiggle matching with serial samples should be used. Some preliminary results of Xia-Shang-Zhou chronology are presented.

  10. Constructing deposition chronologies for peat deposits using radiocarbon dating

    Directory of Open Access Journals (Sweden)

    N. Piotrowska

    2011-06-01

    Full Text Available Radiocarbon dating is one of the main methods used to establish peat chronologies. This article reviews the basis of the method and its application to dating of peat deposits. Important steps in the radiocarbon dating procedure are described, including selection and extraction of material (and fractions for dating, chemical and physical preparation of media suitable for measurements, measurements of 14C activity or concentration, calculations, calibration of results and age-depth modelling.

  11. Tanshinones extend chronological lifespan in budding yeast Saccharomyces cerevisiae.

    Science.gov (United States)

    Wu, Ziyun; Song, Lixia; Liu, Shao Quan; Huang, Dejian

    2014-10-01

    Natural products with anti-aging property have drawn great attention recently but examples of such compounds are exceedingly scarce. By applying a high-throughput assay based on yeast chronological lifespan measurement, we screened the anti-aging activity of 144 botanical materials and found that dried roots of Salvia miltiorrhiza Bunge have significant anti-aging activity. Tanshinones isolated from the plant including cryptotanshione, tanshinone I, and tanshinone IIa, are the active components. Among them, cryptotanshinone can greatly extend the budding yeast Saccharomyces cerevisiae chronological lifespan (up to 2.5 times) in a dose- and the-time-of-addition-dependent manner at nanomolar concentrations without disruption of cell growth. We demonstrate that cryptotanshinone prolong chronological lifespan via a nutrient-dependent regime, especially essential amino acid sensing, and three conserved protein kinases Tor1, Sch9, and Gcn2 are required for cryptotanshinone-induced lifespan extension. In addition, cryptotanshinone significantly increases the lifespan of SOD2-deleted mutants. Altogether, those data suggest that cryptotanshinone might be involved in the regulation of, Tor1, Sch9, Gcn2, and Sod2, these highly conserved longevity proteins modulated by nutrients from yeast to humans.

  12. Construction of reliable radiocarbon-based chronologies for speleothems

    Science.gov (United States)

    Lechleitner, Franziska; Fohlmeister, Jens; McIntyre, Cameron; Baldini, Lisa M.; Jamieson, Robert A.; Hercman, Helena; Gasiorowski, Michal; Pawlak, Jacek; Stefaniak, Krzysztof; Socha, Pawel; Eglinton, Timothy I.; Baldini, James U. L.

    2016-04-01

    Speleothems have become one of the most widely applied archives for paleoclimate research. One of their key advantages is their amenability for U-series dating, often producing excellent high precision chronologies. However, stalagmites with high detrital Th or very low U concentrations are problematic to date using U-series, and sometimes need to be discarded from further paleoclimate analysis. Radiocarbon chronologies could present an alternative for stalagmites that cannot be dated using U-series, if offsets from the "dead carbon fraction" (DCF) can be resolved. The DCF is a variable reservoir effect introduced by the addition of 14C-dead carbon from host rock dissolution and soil organic matter. We present a novel age modeling technique that provides accurate 14C-based chronologies for stalagmites. As this technique focuses on the long-term decay pattern of 14C, it is only applicable on stalagmites that show no secular variability in their 14C-depth profiles, but is independent of short-term DCF variations. In order to determine whether a stalagmite is suitable for this method without direct knowledge of long-term trends in the DCF, we highlight how other geochemical proxies (δ13C, Mg/Ca) can provide additional information on changes in karst hydrology, soil conditions, and climate that would affect DCF. We apply our model on a previously published U-Th dated stalagmite 14C dataset from Heshang Cave, China with excellent results, followed by a previously 'undateable' stalagmite from southern Poland.

  13. Vortex induced vibrations of free span pipelines

    Energy Technology Data Exchange (ETDEWEB)

    Koushan, Kamran

    2009-07-01

    Pipelines from offshore petroleum fields must frequently pass over areas with uneven sea floor. In such cases the pipeline may have free spans when crossing depressions. Hence, if dynamic loads can occur, the free span may oscillate and time varying stresses may give unacceptable fatigue damage. A major source for dynamic stresses in free span pipelines is vortex induced vibrations (VIV) caused by steady current. This effect is in fact dominating on deep water pipelines since wave induced velocities and accelerations will decay with increasing water depth. The challenge for the industry is then to verify that such spans can sustain the influence from the environment throughout the lifetime of the pipeline. The aim of the present project is to improve the understanding of vortex induced vibrations (VIV) of free span pipelines, and thereby improve methods, existing computer programs and guidelines needed for design verification. This will result in more cost effective and reliable offshore pipelines when laid on a very rugged sea floor. VIV for multiple span pipeline is investigated and the dynamical interaction between adjacent spans has been shown. The interaction may lead to increased or decreased response of each spans depending on the current speed and the properties for the two spans. The extension of the contact zone between the spans and sea floor parameters will of course also be important for the interaction effect. The influence from temperature variation on vortex induced vibrations has been demonstrated. The response frequency is influenced through changes in pipe tension and sag. Both increase and decrease of the response frequency may be experienced. Moreover, it is shown that the influence from snaking of the pipe on the temperature effect is small, at least for large diameter pipes. A free span pipeline will necessarily oscillate close to the seabed. The presence of the seabed will therefore have some influences on the ambient flow profile and also

  14. Spanning organizational boundaries to manage creative processes:

    DEFF Research Database (Denmark)

    Andersen, Poul Houman; Kragh, Hanne; Lettl, Christopher

    2013-01-01

    creative talent, b) create shared identity, and c) combine and integrate knowledge in innovation projects involving external actors. We study boundary spanning activities in two creative projects in the LEGO group. One involves identifying and integrating deep, specialized knowledge, the other focuses...

  15. Performance, Career Dynamics, and Span of Control

    DEFF Research Database (Denmark)

    Smeets, Valerie Anne Rolande; Waldman, Michael; Warzynski, Frederic Michel Patrick

    . In this paper we first extend the theoretical literature on the scale-of-operations effect to allow firms’ beliefs concerning a manager’s ability to evolve over the manager’s career, where much of our focus is the determinants of span of control. We then empirically investigate testable predictions from...

  16. Boundary Spanning in Global Software Development

    DEFF Research Database (Denmark)

    Søderberg, Anne-Marie; Romani, Laurence

    of Indian IT vendor managers who are responsible for developing client relations and coordinating complex global development projects. The authors revise a framework of boundary spanning leadership practices to adapt it to an offshore outsourcing context. The empirical investigation highlights how...

  17. Variable Span Filters for Speech Enhancement

    DEFF Research Database (Denmark)

    Jensen, Jesper Rindom; Benesty, Jacob; Christensen, Mads Græsbøll

    2016-01-01

    optimal filters using a joint diagonalization as a basis. This gives excellent control over the performance, as we can optimize for noise reduction or signal distortion performance. Results from real data experiments show that the proposed variable span filters can achieve better performance than existing...

  18. SPAN - Terminal sterilization process analysis program

    Science.gov (United States)

    1969-01-01

    Computer program, SPAN, measures the dry heat thermal sterilization process applied to a planetary capsule and calculates the time required for heat application, steady state conditions, and cooling. The program is based on the logarithmic survival of micro-organisms. Temperature profiles must be input on tape.

  19. SPAN C - Terminal sterilization process analysis program

    Science.gov (United States)

    1969-01-01

    Computer program, SPAN-C, measures the dry heat thermal sterilization process applied to a planetary capsule and calculates the time required for heat application, steady state conditions, and cooling. The program is based on the logarithmic survival of micro-organisms. Temperature profiles must be input on cards.

  20. [Chronological table of Mr. and Mrs. Curie and Mr. and Mrs. Joliot-Curie--in connection with the 100-year anniversary since Dr. H. Becquerel discovered radial ray in 1896].

    Science.gov (United States)

    Yamada, M

    1996-01-01

    This year (1996) is the 100th year since Dr. Henri Becquerel discovered radial rays in 1896 in France. In 1897, Dr. Pierre Curie and Marie Curie preliminarily reported the existence of polonium and radium which have radioactivity. H. Becquerel, Pierre and Marie Curie were awarded the Nobel Chemical Prize for discovering artificial radioactivity in 1935. I report herein the chronological table of Mr. and Mrs. Curie and Mr. and Mrs. Joliot-Curie spanning about one century.

  1. A Lattice Spanning-Tree Entropy Function

    OpenAIRE

    Glasser, ML; Lamb, George

    2005-01-01

    The function $$W(aq,b)=\\int\\int_0^{2\\pi}\\ln[1-a\\cos x-b\\cos y-(1-a-b)\\cos(x+y)]dxdy$$ which expresses the spanning-tree entropy for various two dimensional lattices, for example, is evaluated directly in terms of standard functions. It is applied to derive several limiting values of the triangular lattice Green function.

  2. Span morphing using the GNATSpar wing

    OpenAIRE

    2016-01-01

    Rigid wings usually fly at sub-optimal conditions generating unnecessary aerodynamic loses represented in flight time, fuel consumption, and unfavourable operational characteristics. High aspect ratio wings have good range and fuel efficiency, but lack manoeuvrability. On the other hand, low aspect ratio wings fly faster and are more manoeuvrable, but have poor aerodynamic performance. Span morphing technology allows integrating both features in a single wing design and allows continuously ad...

  3. Attention Span, Anxiety and Benzodiazepine Receptors

    Science.gov (United States)

    1991-02-26

    represent a new class of nootropic druos witn a s9intricant clinical potential. 2 FINAL TECHNICAL REPORT ON GRANT AFOSR-87-0364 ENTITLED "ATTENTION SPAN...acquisition and retention of novel aversively motivated goal-directed behavior. This nootropic action may be linked to the flumazenil enhanced brain...metabolism, as revealed by oxygen utilization in the rat forebrain [32]. The nootropic effect may also be linked to increased protein synthesis in the CNS, an

  4. Vision in Flies: Measuring the Attention Span.

    Science.gov (United States)

    Koenig, Sebastian; Wolf, Reinhard; Heisenberg, Martin

    2016-01-01

    A visual stimulus at a particular location of the visual field may elicit a behavior while at the same time equally salient stimuli in other parts do not. This property of visual systems is known as selective visual attention (SVA). The animal is said to have a focus of attention (FoA) which it has shifted to a particular location. Visual attention normally involves an attention span at the location to which the FoA has been shifted. Here the attention span is measured in Drosophila. The fly is tethered and hence has its eyes fixed in space. It can shift its FoA internally. This shift is revealed using two simultaneous test stimuli with characteristic responses at their particular locations. In tethered flight a wild type fly keeps its FoA at a certain location for up to 4s. Flies with a mutation in the radish gene, that has been suggested to be involved in attention-like mechanisms, display a reduced attention span of only 1s.

  5. Vision in Flies: Measuring the Attention Span.

    Directory of Open Access Journals (Sweden)

    Sebastian Koenig

    Full Text Available A visual stimulus at a particular location of the visual field may elicit a behavior while at the same time equally salient stimuli in other parts do not. This property of visual systems is known as selective visual attention (SVA. The animal is said to have a focus of attention (FoA which it has shifted to a particular location. Visual attention normally involves an attention span at the location to which the FoA has been shifted. Here the attention span is measured in Drosophila. The fly is tethered and hence has its eyes fixed in space. It can shift its FoA internally. This shift is revealed using two simultaneous test stimuli with characteristic responses at their particular locations. In tethered flight a wild type fly keeps its FoA at a certain location for up to 4s. Flies with a mutation in the radish gene, that has been suggested to be involved in attention-like mechanisms, display a reduced attention span of only 1s.

  6. Critical review of a new volcanic eruption chronology

    Science.gov (United States)

    Neuhäuser, Dagmar L.; Neuhäuser, Ralph

    2016-04-01

    Sigl. et al. (2015, Nature) present historical evidence for 32 volcanic eruptions to evaluate their new polar ice core 10-Be chronology - 24 are dated within three years of sulfur layers in polar ice. Most of them can be interpreted as weather phenomena (Babylonia: disk of sun like moon, reported for only one day, e.g. extinction due to clouds), Chinese sunspot reports (pellet, black vapor, etc.), solar eclipses, normal ice-halos and coronae (ring, bow, etc.), one aurora (redness), red suns due to mist drops in wet fog or fire-smoke, etc. Volcanic dust may facilitate detections of sunspots and formation of Bishop's ring, but tend to inhibit ice-halos, which are otherwise often reported in chronicles. We are left with three reports possibly indicating volcanic eruptions, namely fulfilling genuine criteria for atmospheric disturbances due to volcanic dust, e.g. bluish or faint sun, orange sky, or fainting of stars for months (BCE 208, 44-42, and 32). Among the volcanic eruptions used to fix the chronology (CE 536, 626, 939, 1257), the reports cited for the 930s deal only with 1-2 days, at least one reports an eclipse. In the new chronology, there is a sulfur detection eight years after the Vesuvius eruption, but none in CE 79. It may appear surprising that, from BCE 500 to 1, all five northern sulfur peaks labeled in figure 2 in Sigl et al. are systematically later by 2-4 years than the (corresponding?) southern peaks, while all five southern peaks from CE 100 to 600 labeled in figure 2 are systematically later by 1-4 years than the (corresponding?) northern peaks. Furthermore, in most of their six strongest volcanic eruptions, temperatures decreased years before their sulfur dating - correlated with weak solar activity as seen in radiocarbon, so that volcanic climate forcing appears dubious here. Also, their 10-Be peaks at CE 775 and 994 are neither significant nor certain in dating.

  7. The problem of the neolithisation process chronology in Povolzhye

    Directory of Open Access Journals (Sweden)

    Aleksandr Vybornov

    2013-12-01

    Full Text Available The Lower and Middle Volga basin regions border the Caucasus and Central Asia in the South. These regions are important in the study of the neolithisation process in Europe and the chronology of Neolithic cultures is of great significance in this respect. New 14C dates of different organic materials from archaeological sites in these regions have been obtained in the last five years. According to these data, the beginning of neolithisation in North Caspian region can be dated to the beginning of the 5th millennium BC; but in the Povolzhye it happened at least a millennium earlier.

  8. Towards new mathematical tools for obtaining chronologies in discontinuous archives

    Science.gov (United States)

    Donner, Reik V.

    2014-05-01

    In the last years, a variety of new mathematical approaches has been developed for obtaining reliable chronologies of geological and geomorphological archives based on a limited set of dating horizons. These new approaches work relatively well for continuous archives, but quickly approach their conceptual limits in the presence of discontinuities. Here, I report first steps towards improving existing mathematical algorithms in their performance regarding unknown discontinuities by integrating complementary information based on variations encoded in other archives. The proposed method is based on the following ingredients: (1) a correlation estimator for arbitrarily spaced time series, (2) a maximization criterion for correlations based on a linear rescaling of the unknown time axis, (3) a procedure allowing an automatic evaluation of minimum-cost paths for performing a sophisticated version of "wiggle-matching", and (4) improving the relative chronologies by adding explicit dates via some additional penalty term. To this end, I will mainly focus on the methodological details associated with the first two steps. Here, correlations between the data set under study and the "reference" archive are evaluated for running windows along the records utilizing a recently developed non-parametric correlation estimator based on a Gaussian kernel function. Allowing for an arbitrary rescaling of the time axis around the respective window midpoint, maximum correlations arise when the windows represent the same time intervals and the rescaled time axis corrects for different material accumulation rates. For sufficiently high-resolution records, the proposed approach can be extended to account also for possible non-linear co-variations between the two considered archives or proxies. By identifying sequences of subsequent windows with particularly high correlations, relative chronologies can be obtained. Moreover, gaps in such sequences are indicative of archive discontinuities and

  9. Teaching about September 11th and Its Aftermath. C-SPAN in the Classroom.

    Science.gov (United States)

    C-SPAN, Washington, DC.

    The events of and since September 11, 2001 have had an immeasurable impact on all facets of people's lives, especially in the United States. The loss of human life, threatened public safety, and the impact of a military response are just some of the issues concerning U.S. citizens and public officials. This C-SPAN in the Classroom series offers…

  10. 沙丁胺醇对果蝇的化蛹、羽化、寿命及抗氧化能力和DNA损伤的影响%Effect of Salbutamol on the Pupation, Emergence, Life Span, Antioxidative Capacity and DNA Damage in Drosophila melanogaster

    Institute of Scientific and Technical Information of China (English)

    孙冰; 林欣大; 张春红

    2014-01-01

    蝇寿命呈现增加的趋势。对果蝇DNA损伤检测的试验表明,经沙丁胺醇处理之后,果蝇细胞就出现损伤,在SCGE的检测下可以观察到DNA损伤形成的拖尾,并且随着浓度的增加损伤情况也越严重,但是彗星图片中没有出现细胞核首尾分离的情况,可知沙丁胺醇并没有引起细胞凋亡。经统计分析,各处理浓度组的“彗星”尾长(Tail length, TL)、尾距(Olive tail moment, OTM)和尾部DNA百分含量(%DNA in tail),与对照组相比,均有显著差异(P<0.05)。【结论】沙丁胺醇对果蝇化蛹和羽化没有显著影响;对果蝇抗氧化系统产生作用,抑制CAT活力,使SOD活力显著增加,使得在较高浓度处理时出现显著延长果蝇的寿命的情况;经沙丁胺醇处理之后,就会引起果蝇DNA损伤并且与对照组存在显著差异,但是并没有出现细胞凋亡的情况。%The objective of this study is to explore the effect of salbutamol on the growth, development, life span, anti-oxidative capacity and DNA damage in Drosophila melanogaster, to further provide the basis for improvement of the more effective detection method.[Method]The 1st-instar larvae were fed with salbutamol and the pupate and emergence of flies were recorded, the pupation rate and the eclosion rate as well as pupation and eclosion time were counted. One day after eclosed, adult flies were fed up with normal medium and salbutamol medium, in which the concentrations of salbutamol were 0.48, 2.4,12 and 24μg·mL-1. Fifty flies for each medium(1﹕1 for male﹕female) and the experiment was repeated for 4 times. The number of lived flies was recorded every day. The medium was replaced every three days until all of the flies died. The 50%lethal time, average longevity and average maximum time were recorded and calculated, respectively. The 3-day old adult flies which feed up with salbutamol or minimum medium were collected. Tissue

  11. Optimisation of glaciological parameters for ice core chronology by implementing counted layers between identified depth levels

    Science.gov (United States)

    Bazin, L.; Lemieux-Dudon, B.; Landais, A.; Guillevic, M.; Kindler, P.; Parrenin, F.; Martinerie, P.

    2014-08-01

    A~recent coherent chronology has been built for 4 Antarctic ice cores and the NorthGRIP (NGRIP) Greenland ice core (Antarctic Ice Core Chronology 2012, AICC2012) using a bayesian approach for ice core dating (Datice). When building the AICC2012 chronology, and in order to prevent any confusion with official ice cores chronology, it has been imposed that the AICC2012 chronology for NGRIP should respect exactly the GICC05 chronology based on layer counting. However, such a strong tuning did not satisfy the hypothesis of independence of background parameters and observations for the NGRIP core as required by Datice. We present here the implementation in Datice of a new type of markers that is better suited to constraints deduced from layer counting: the markers of age-difference. Using this type of markers for NGRIP in a 5 cores dating exercise with Datice, we have performed several sensitivity tests and show that the new ice core chronologies obtained with these new markers do not differ by more than 400 years from AICC2012 for Antarctic ice cores and by more than 130 years from GICC05 for NGRIP over the last 60 000 years. With this new parameterization, the accumulation rate and lock-in depth associated with NGRIP are more coherent with independent estimates than those obtained in AICC2012. While these new chronologies should not be used yet as new ice core chronologies, the improved methodology presented here should be considered in the next coherent ice core dating exercise.

  12. Decentralized Pricing in Minimum Cost Spanning Trees

    DEFF Research Database (Denmark)

    Hougaard, Jens Leth; Moulin, Hervé; Østerdal, Lars Peter

    In the minimum cost spanning tree model we consider decentralized pricing rules, i.e. rules that cover at least the ecient cost while the price charged to each user only depends upon his own connection costs. We de ne a canonical pricing rule and provide two axiomatic characterizations. First......, the canonical pricing rule is the smallest among those that improve upon the Stand Alone bound, and are either superadditive or piece-wise linear in connection costs. Our second, direct characterization relies on two simple properties highlighting the special role of the source cost....

  13. Interorganizational Boundary Spanning in Global Software Development

    DEFF Research Database (Denmark)

    Søderberg, Anne-Marie; Romani, Laurence

    to virtuality and cultural diversity. This paper, which draws on a case study of collaborative work in a global software development project, focuses on key boundary spanners in an Indian vendor company, who are responsible for developing trustful and sustainable client relations and coordinating complex......, and which skills and competencies they draw on in their efforts to deal with emerging cross-cultural issues in a way that paves ground for developing a shared understanding and common platform for the client and vendor representatives. A framework of boundary spanning leadership practices is adapted...

  14. The Problem of Predecessors on Spanning Trees

    Directory of Open Access Journals (Sweden)

    V. S. Poghosyan

    2011-01-01

    Full Text Available We consider the equiprobable distribution of spanning trees on the square lattice. All bonds of each tree can be oriented uniquely with respect to an arbitrary chosen site called the root. The problem of predecessors is to find the probability that a path along the oriented bonds passes sequentially fixed sites i and j. The conformal field theory for the Potts model predicts the fractal dimension of the path to be 5/4. Using this result, we show that the probability in the predecessors problem for two sites separated by large distance r decreases as P(r ∼ r −3/4. If sites i and j are nearest neighbors on the square lattice, the probability P(1 = 5/16 can be found from the analytical theory developed for the sandpile model. The known equivalence between the loop erased random walk (LERW and the directed path on the spanning tree states that P(1 is the probability for the LERW started at i to reach the neighboring site j. By analogy with the self-avoiding walk, P(1 can be called the return probability. Extensive Monte-Carlo simulations confirm the theoretical predictions.

  15. Biological versus chronological ovarian age: implications for assisted reproductive technology

    Directory of Open Access Journals (Sweden)

    Tredway Donald

    2009-09-01

    Full Text Available Abstract Background Women have been able to delay childbearing since effective contraception became available in the 1960s. However, fertility decreases with increasing maternal age. A slow but steady decrease in fertility is observed in women aged between 30 and 35 years, which is followed by an accelerated decline among women aged over 35 years. A combination of delayed childbearing and reduced fecundity with increasing age has resulted in an increased number and proportion of women of greater than or equal to 35 years of age seeking assisted reproductive technology (ART treatment. Methods Literature searches supplemented with the authors' knowledge. Results Despite major advances in medical technology, there is currently no ART treatment strategy that can fully compensate for the natural decline in fertility with increasing female age. Although chronological age is the most important predictor of ovarian response to follicle-stimulating hormone, the rate of reproductive ageing and ovarian sensitivity to gonadotrophins varies considerably among individuals. Both environmental and genetic factors contribute to depletion of the ovarian oocyte pool and reduction in oocyte quality. Thus, biological and chronological ovarian age are not always equivalent. Furthermore, biological age is more important than chronological age in predicting the outcome of ART. As older patients present increasingly for ART treatment, it will become more important to critically assess prognosis, counsel appropriately and optimize treatment strategies. Several genetic markers and biomarkers (such as anti-Müllerian hormone and the antral follicle count are emerging that can identify women with accelerated biological ovarian ageing. Potential strategies for improving ovarian response include the use of luteinizing hormone (LH and growth hormone (GH. When endogenous LH levels are heavily suppressed by gonadotrophin-releasing hormone analogues, LH supplementation may help

  16. All about Animal Life Cycles. Animal Life for Children. [Videotape].

    Science.gov (United States)

    2000

    While watching the development from tadpole to frog, caterpillar to butterfly, and pup to wolf, children learn about the life cycles of animals, the different stages of development, and the average life spans of a variety of creatures. This videotape correlates to the following National Science Education Standards for Life Science: characteristics…

  17. Life in Transition

    DEFF Research Database (Denmark)

    Overgaard, Dorthe; Grufstedt Kjeldgaard, Heidi; Egerod, Ingrid

    2012-01-01

    BACKGROUND:: A left ventricular assist device (LVAD) is used as a bridge to transplantation in patients with acute heart failure. The device is a major bodily invasion that challenges everyday life. Only few studies have explored the psychosocial adjustments of patients living with an LVAD....... OBJECTIVE:: The aim of this study was to explore the lived experience of patients with LVAD. METHODS:: The present study had a qualitative explorative design using in-depth interviews of 10 adult patients that had experienced life with an LVAD from 2008 to 2010 in Denmark. We constructed an interview guide...... with themes relating to the chronology of the illness trajectory. Data were managed by the qualitative computer package NVivo 8. As a theoretical framework, we chose a life-stage model for the main theme: Life With LVAD. The model describes the developmental tasks in each age group, and we looked...

  18. Origin and chronology of chondritic components: A review

    Science.gov (United States)

    Krot, A. N.; Amelin, Y.; Bland, P.; Ciesla, F. J.; Connelly, J.; Davis, A. M.; Huss, G. R.; Hutcheon, I. D.; Makide, K.; Nagashima, K.; Nyquist, L. E.; Russell, S. S.; Scott, E. R. D.; Thrane, K.; Yurimoto, H.; Yin, Q.-Z.

    2009-09-01

    Mineralogical observations, chemical and oxygen-isotope compositions, absolute 207Pb- 206Pb ages and short-lived isotope systematics ( 7Be- 7Li, 10Be- 10B, 26Al- 26Mg, 36Cl- 36S, 41Ca- 41K, 53Mn- 53Cr, 60Fe- 60Ni, 182Hf- 182W) of refractory inclusions [Ca,Al-rich inclusions (CAIs) and amoeboid olivine aggregates (AOAs)], chondrules and matrices from primitive (unmetamorphosed) chondrites are reviewed in an attempt to test (i) the x-wind model vs. the shock-wave model of the origin of chondritic components and (ii) irradiation vs. stellar origin of short-lived radionuclides. The data reviewed are consistent with an external, stellar origin for most short-lived radionuclides ( 7Be, 10Be, and 36Cl are important exceptions) and a shock-wave model for chondrule formation, and provide a sound basis for early Solar System chronology. They are inconsistent with the x-wind model for the origin of chondritic components and a local, irradiation origin of 26Al, 41Ca, and 53Mn. 10Be is heterogeneously distributed among CAIs, indicating its formation by local irradiation and precluding its use for the early solar system chronology. 41Ca- 41K, and 60Fe- 60Ni systematics are important for understanding the astrophysical setting of Solar System formation and origin of short-lived radionuclides, but so far have limited implications for the chronology of chondritic components. The chronological significance of oxygen-isotope compositions of chondritic components is limited. The following general picture of formation of chondritic components is inferred. CAIs and AOAs were the first solids formed in the solar nebula ˜4567-4568 Myr ago, possibly within a period of events in nebular region(s) with high ambient temperature (at or above condensation temperature of forsterite), either throughout the inner protoplanetary disk (1-4 AU) or in a localized region near the proto-Sun ( -10‰) and have ( 26Al/ 27Al) 0 similar to those in chondrules (events in regions with low ambient temperature

  19. Chronology and origin of VMS deposits in Xinjiang, NW CHINA

    Institute of Scientific and Technical Information of China (English)

    CHEN; Fuwen(陈富文); LI; Huaqin(李华芹); WANG; Denghong(王登红); XIE; Caifu(谢才富); LU; Yuanfa(路远发)

    2002-01-01

    VMS deposits in Xinjiang, NW China are widespread in the Altay, Tianshan and West Kunlun orogenic belt, mainly formed during the Proterozoic rifting and Phanerozoic post-orogenic extension and are related to the bimodal volcanism. The VMS deposits are middle and small in scale. According to assemblages of metallogenetic elements, they can be divided into four types (Cu-Zn, Cu-S, Pb-Zn-Cu and Pb-Zn types) with the Cu-Zn and Pb-Zn types being the most important ones. Research of isotopic chronology shows that the VMS deposits in Xinjiang were formed during the Proterozoic, Ordovician, Deovonian, Carboniferous and Permian periods and usually underwent multi-stage mineralization, especially the large-sized deposits usually have post- volcanic superimposed mineralization by tectonomagmatic or metamorphic hydrothermal metallogenic fluids.

  20. Asbestos: a chronology of its origins and health effects.

    Science.gov (United States)

    Murray, R

    1990-01-01

    The emotionalised subject of asbestos is treated in chronological terms: how the "magic mineral" known in ancient times in Europe and Asia became in the late nineteenth century an important industrial resource of particular interest to the navies of the world; and how its malign effects gradually became apparent during the present century. The media have made asbestos a notorious villain, but it still has properties and applications useful to society if they are properly controlled in the same way as other industrial hazards. One important application is the manufacture of asbestos cement pipes which are a convenient and cheap method of providing water supplies and sewage disposal for developing countries. An appeal is made for prudence and not hysteria in relation to the use of mineral fibres of all types. PMID:2088320

  1. Cranial ultrasound and chronological changes in molybdenum cofactor deficiency

    Energy Technology Data Exchange (ETDEWEB)

    Serrano, Mercedes; Dias, Anna P.; Perez-Duenas, Belen; Campistol, Jaume; Garcia-Cazorla, Angels [Hospital Sant Joan de Deu, Department of Pediatric Neurology, Paseo de Sant Joan de Deu, Barcelona (Spain); Lizarraga, Isabel [Hospital Sant Joan de Deu, Department of Neonatology, Barcelona (Spain); Reiss, Jochen [University of Goettingen, Institute for Human Genetics, Goettingen (Germany); Vilaseca, Maria A.; Artuch, Rafael [Hospital Sant Joan de Deu, Clinical Biochemistry Department, Barcelona (Spain)

    2007-10-15

    Molybdenum cofactor is essential for the function of three human enzymes: sulphite oxidase, xanthine dehydrogenase, and aldehyde oxidase. Molybdenum cofactor deficiency is a rare autosomal recessively inherited disease. Disturbed development and damage to the brain may occur as a result of accumulation of toxic levels of sulphite. The CT and MRI findings include severe early brain abnormalities and have been widely reported, but the cranial US imaging findings have seldom been reported. We report a chronological series of cranial US images obtained from an affected infant that show the rapid development of cerebral atrophy, calcifications and white matter cysts. Our report supports the utility of cranial US, a noninvasive bed-side technique, in the detection and follow-up of these rapidly changing lesions. (orig.)

  2. Holographic Protection of Chronology in Universes of the Godel Type

    CERN Document Server

    Boyda, E; Horava, P; Varadarajan, U; Boyda, Edward; Ganguli, Surya; Horava, Petr; Varadarajan, Uday

    2003-01-01

    We analyze the structure of supersymmetric Godel-like cosmological solutions of string theory. Just as the original four-dimensional Godel universe, these solutions represent rotating, topologically trivial cosmologies with a homogeneous metric and closed timelike curves. First we focus on "phenomenological" aspects of holography, and identify the preferred holographic screens associated with inertial comoving observers in Godel universes. We find that holography can serve as a chronology protection agency: The closed timelike curves are either hidden behind the holographic screen, or broken by it into causal pieces. In fact, holography in Godel universes has many features in common with de Sitter space, suggesting that Godel universes could represent a supersymmetric laboratory for addressing the conceptual puzzles of de Sitter holography. Then we initiate the investigation of "microscopic" aspects of holography of Godel universes in string theory. We show that Godel universes are T-dual to pp-waves, and use...

  3. Ştefania Cristescu-Golopenţia's Chronology

    Directory of Open Access Journals (Sweden)

    SANDA GOLOPENŢIA

    2013-07-01

    Full Text Available The present Chronology brings together data from the personal archive of Şt.C.-G. with data accumulated during the editing of her published and posthumous work that Sanda Golopenţia undertook after 1989. The author specifically calls attention to the new data regarding Şt.C.-G.'s 1938 and 1939 regional research in Ţara Oltului (the Olt County, the research she conducted in 1945 and 1947 in the Gurghiu Valley, and the social inquiry on the daily lives of her students in the Industrial Colege "Protopopul Tudor Economul" from Bucharest (1942-1943. The bibliography of St.C.-G.'s sociological, pedagogical and literary works was updated.

  4. Northeastern North American Pleistocene megafauna chronologically overlapped minimally with Paleoindians

    Science.gov (United States)

    Boulanger, Matthew T.; Lyman, R. Lee

    2014-02-01

    It has long been argued that specialized big-game-hunting Paleoindians were responsible for the extinction of three dozen large-bodied mammalian genera in North America. In northeastern North America, the overkill hypothesis cannot be tested on the basis of associations of Paleoindian artifacts and remains of extinct mammals because no unequivocal associations are known. The overkill hypothesis requires Paleoindians to be contemporaneous with extinct mammalian taxa and this provides a means to evaluate the hypothesis, but contemporaneity does not confirm overkill. Blitzkrieg may produce evidence of contemporaneity but it may not, rendering it difficult to test. Overkill and Blitzkrieg both require large megafaunal populations. Chronological data, Sporormiella abundance, genetics, and paleoclimatic data suggest megafauna populations declined prior to human colonization and people were only briefly contemporaneous with megafauna. Local Paleoindians may have only delivered the coup de grace to small scattered and isolated populations of megafauna.

  5. Social Network Changes and Life Events across the Life Span: A Meta-Analysis

    Science.gov (United States)

    Wrzus, Cornelia; Hanel, Martha; Wagner, Jenny; Neyer, Franz J.

    2013-01-01

    For researchers and practitioners interested in social relationships, the question remains as to how large social networks typically are, and how their size and composition change across adulthood. On the basis of predictions of socioemotional selectivity theory and social convoy theory, we conducted a meta-analysis on age-related social network…

  6. An 854-Year Tree-Ring Chronology of Scots Pine for South-West Finland

    Directory of Open Access Journals (Sweden)

    Helama Samuli

    2014-04-01

    Full Text Available A near-millennial tree-ring chronology (AD 1147-2000 is presented for south-west Finland and analyzed using dendroclimatic methods. This is a composite chronology comprising samples both from standing pine trees (Pinus sylvestris L. and subfossil trunks as recovered from the lake sediments, with a total sample size of 189 tree-ring sample series. The series were dendrochronologically cross-dated to exact calendar years to portray variability in tree-ring widths on inter-annual and longer scales. Al though the studied chronology correlates statistically significantly with other long tree-ring width chronologies from Finland over their common period (AD 1520-1993, the south-west chronology did not exhibit similarly strong mid-summer temperature or spring/early-summer precipitation signals in comparison to published chronologies. On the other hand, the south-west chronology showed highest correlations to the North Atlantic Oscillation indices in winter/spring months, this association following a dendroclimatic feature common to pine chronologies over the region and adjacent areas. Paleoclimatic comparison showed that tree-rings had varied similarly to central European spring temperatures. It is postulated that the collected and dated tree-ring material could be studied for wood surface reflectance (blue channel light intensity and stable isotopes, which both have recently shown to correlate notably well with summer temperatures.

  7. Relationships between Chronological Age, Developmental Age, and Standardized Achievement Tests in Kindergarten.

    Science.gov (United States)

    Freberg, Laura

    1991-01-01

    Evaluated chronological age and results of Gesell School Readiness Test as predictors of kindergarten performance as measured by Stanford Achievement Test. Results from 284 kindergarten children indicated that both chronological and developmental age provided good predictors of Stanford Achievement Test performance in kindergarten. Findings have…

  8. Environmental factors influence lesser scaup migration chronology and population monitoring

    Science.gov (United States)

    Finger, Taylor A.; Afton, Alan D.; Schummer, Michael L.; Petrie, Scott A.; Badzinski, Shannon S.; Johnson, Michael A.; Szymanski, Michael L.; Jacobs, Kevin J.; Olsen, Glenn H.; Mitchell, Mark

    2016-01-01

    Identifying environmental metrics specific to lesser scaup (Aythya affinis; scaup) spring migration chronology may help inform development of conservation, management and population monitoring. Our objective was to determine how environmental conditions influence spring migration of lesser scaup to assess the effectiveness of the Waterfowl Breeding Population and Habitat Survey in accurately estimating scaup populations. We first compared peak timing of mallard (Anas platyrhynchos) and scaup migration from weekly ground surveys in North Dakota, USA because the Waterfowl Breeding Population and Habitat Survey is designed to capture annual mallard migration. As predicted, we detected that peak timing of scaup and mallard migrations differed in 25 of 36 years investigated (1980–2010). We marked scaup with satellite transmitters (n = 78; 7,403 locations) at Long Point, Lake Erie, Ontario, Canada; Pool 19 of the Mississippi River, Iowa and Illinois, USA; and Presque Isle Bay, Lake Erie, Pennsylvania, USA. We tested the assumption that our marked scaup were representative of the continental population using the traditional survey area by comparing timing of migration of marked birds and scaup counted in the North Dakota Game and Fish Department survey. We detected a strong positive correlation between marked scaup and the survey data, which indicated that marked scaup were representative of the population. We subsequently used our validated sample of marked scaup to investigate the effects of annual variation in temperature, precipitation, and ice cover on spring migration chronology in the traditional and eastern survey areas of the Waterfowl Breeding Population and Habitat Survey, 2005–2010. We evaluated competing environmental models to explain variation in timing and rate of scaup migration at large-scale and local levels. Spring migration of scaup occurred earlier and faster during springs with warmer temperatures and greater precipitation, variables known

  9. Systematic Uncertainties of Glacial Chronologies Based on Surface Exposure Dating

    Science.gov (United States)

    Ilgner, J.; Zech, R.; Baechtiger, C.; Kubik, P. W.; Veit, H.

    2008-12-01

    Surface exposure dating using terrestrial cosmogenic nuclides provides the opportunity to establish glacial chronologies in semi-arid high mountain regions, where the lack of organic material for radiocarbon dating has limited our knowledge about the timing and the causes of glacial advances so far. However, several scaling systems and calculation schemes exist. This can result in significant systematic uncertainties, particularly at high altitudes as e.g. in the Central Andes. We present and discuss previously published exposure ages from Bolivia and Argentina in order to illustrate the extent of the current uncertainties. It is neither possible to unambiguously determine whether the local Last Glacial Maximum (local LGM) in the tropics occurred in-phase with or predated the global LGM, nor can the subsequent Late Glacial stages be dated accurately enough to infer temperature or precipitation changes at millennial-scale timescales. We then also present new results from the Tres Lagunas in the Sierra de Santa Victoria, NW Argentina. There we can compare our glacial exposure age chronology with bracketing radiocarbon ages from lake sediments. The Tres Lagunas may thus serve as a high-altitude calibration site for 10Be dating. Paleoclimatically, we conclude that glacial deposits in NW-Argentina document glacial advances in-phase with the global LGM, but that the prominent moraines there date to the Late Glacial. This coincides with the well-documented intensification and/or southward shift of the tropical circulation and reflects the strong precipitation-sensitivity of glaciers in arid and semi-arid environments.

  10. Galactic Archaeology and Minimum Spanning Trees

    CERN Document Server

    Macfarlane, B A; Flynn, C M L

    2015-01-01

    Chemical tagging of stellar debris from disrupted open clusters and associations underpins the science cases for next-generation multi-object spectroscopic surveys. As part of the Galactic Archaeology project TraCD (Tracking Cluster Debris), a preliminary attempt at reconstructing the birth clouds of now phase-mixed thin disk debris is undertaken using a parametric minimum spanning tree (MST) approach. Empirically-motivated chemical abundance pattern uncertainties (for a 10-dimensional chemistry-space) are applied to NBODY6-realised stellar associations dissolved into a background sea of field stars, all evolving in a Milky Way potential. We demonstrate that significant population reconstruction degeneracies appear when the abundance uncertainties approach 0.1 dex and the parameterised MST approach is employed; more sophisticated methodologies will be required to ameliorate these degeneracies.

  11. Faster generation of random spanning trees

    CERN Document Server

    Kelner, Jonathan A

    2009-01-01

    In this paper, we set forth a new algorithm for generating approximately uniformly random spanning trees in undirected graphs. We show how to sample from a distribution that is within a multiplicative $(1+\\delta)$ of uniform in expected time $\\TO(m\\sqrt{n}\\log 1/\\delta)$. This improves the sparse graph case of the best previously known worst-case bound of $O(\\min \\{mn, n^{2.376}\\})$, which has stood for twenty years. To achieve this goal, we exploit the connection between random walks on graphs and electrical networks, and we use this to introduce a new approach to the problem that integrates discrete random walk-based techniques with continuous linear algebraic methods. We believe that our use of electrical networks and sparse linear system solvers in conjunction with random walks and combinatorial partitioning techniques is a useful paradigm that will find further applications in algorithmic graph theory.

  12. Increasing the weight of minimum spanning trees

    Energy Technology Data Exchange (ETDEWEB)

    Frederickson, G.N.; Solis-Oba, R. [Purdue Univ., West Lafayette, IN (United States)

    1996-12-31

    Given an undirected connected graph G and a cost function for increasing edge weights, the problem of determining the maximum increase in the weight of the minimum spanning trees of G subject to a budget constraint is investigated. Two versions of the problem are considered. In the first, each edge has a cost function that is linear in the weight increase. An algorithm is presented that solves this problem in strongly polynomial time. In the second version, the edge weights are fixed but an edge can be removed from G at a unit cost. This version is shown to be NP-hard. An {Omega}(1/ log k)-approximation algorithm is presented for it, where k is the number of edges to be removed.

  13. NSI directed to continue SPAN's functions

    Science.gov (United States)

    Rounds, Fred

    1991-01-01

    During a series of network management retreats in June and July 1990, representatives from NASA Headquarters Codes O and S agreed on networking roles and responsibilities for their respective organizations. The representatives decided that NASA Science Internet (NSI) will assume management of both the Space Physics Analysis Network (SPAN) and the NASA Science Network (NSN). SPAN is now known as the NSI/DECnet, and NSN is now known as the NSI/IP. Some management functions will be distributed between Ames Research Center (ARC) and Goddard Space Flight Center (GSFC). NSI at ARC has the lead role for requirements generation and networking engineering. Advanced Applications and the Network Information Center is being developed at GSFC. GSFC will lead the NSI User Services, but NSI at Ames will continue to provide the User Services during the transition. The transition will be made as transparent as possible for the users. DECnet service will continue, but is now directly managed by NSI at Ames. NSI will continue to work closely with routing center managers at other NASA centers, and has formed a transition team to address the change in management. An NSI/DECnet working group had also been formed as a separate engineering group within NSI to plan the transition to Phase 5, DECnet's approach to Open System Integration (OSI). Transition is not expected for a year or more due to delays in produce releases. Plans to upgrade speeds in tail circuits and the backbone are underway. The proposed baseline service for new connections is up to 56 Kbps; 9.6 Kbps lines will gradually be upgraded as requirements dictate. NSI is in the process of consolidating protocol traffic, tail circuits, and the backbone. Currently NSI's backbone is fractional T1; NSI will go to full T1 service as soon as it is feasible.

  14. Turning Simple Span into Complex Span: Time for Decay or Interference from Distractors?

    Science.gov (United States)

    Lewandowsky, Stephan; Geiger, Sonja M.; Morrell, Daniel B.; Oberauer, Klaus

    2010-01-01

    We investigated the effects of the duration and type of to-be-articulated distractors during encoding of a verbal list into short-term memory (STM). Distractors and to-be-remembered items alternated during list presentation, as in the complex-span task that underlies much of working-memory research. According to an interference model of STM, known…

  15. The geometry of inner spanning trees for planar polygons

    Energy Technology Data Exchange (ETDEWEB)

    Ivanov, Alexandr O; Tuzhilin, Alexey A [P.G. Demidov Yaroslavl State University, Yaroslavl (Russian Federation)

    2012-04-30

    We study the geometry of minimal inner spanning trees for planar polygons (that is, spanning trees whose edge-intervals lie in these polygons). We construct analogues of Voronoi diagrams and Delaunay triangulations, prove that every minimal inner spanning tree is a subgraph of an appropriate Delaunay triangulation, and describe the possible structure of the cells of such triangulations.

  16. A Vertex Oriented Approach to Minimum Cost Spanning Tree Problems

    NARCIS (Netherlands)

    Ciftci, B.B.; Tijs, S.H.

    2007-01-01

    In this paper we consider spanning tree problems, where n players want to be connected to a source as cheap as possible. We introduce and analyze (n!) vertex oriented construct and charge procedures for such spanning tree situations leading in n steps to a minimum cost spanning tree and a cost shari

  17. The generalized minimum spanning tree polytope and related polytopes

    NARCIS (Netherlands)

    Pop, P.C.

    2001-01-01

    The Generalized Minimum Spanning Tree problem denoted by GMST is a variant of the classical Minimum Spanning Tree problem in which nodes are partitioned into clusters and the problem calls for a minimum cost tree spanning at least one node from each cluster. A different version of the problem, calle

  18. A reevaluation of the Pallett Creek earthquake chronology based on new AMS radiocarbon dates, San Andreas fault, California

    Science.gov (United States)

    Scharer, K.M.; Biasi, G.P.; Weldon, R.J.

    2011-01-01

    The Pallett Creek paleoseismic record occupies a keystone position in most attempts to develop rupture histories for the southern San Andreas fault. Previous estimates of earthquake ages at Pallett Creek were determined by decay counting radiocarbon methods. That method requires large samples which can lead to unaccounted sources of uncertainty in radiocarbon ages because of the heterogeneous composition of organic layers. In contrast, accelerator mass spectrometry (AMS) radiocarbon dates may be obtained from small samples that have known carbon sources and also allow for a more complete sampling of the section. We present 65 new AMS radiocarbon dates that span nine ground-rupturing earthquakes at Pallett Creek. Overall, the AMS dates are similar to and reveal no dramatic bias in the conventional dates. For many layers, however, individual charcoal samples were younger than the conventional dates, leading to earthquake ages that are overall slightly younger than previously reported. New earthquake ages are determined by Bayesian refinement of the layer ages based on stratigraphic ordering and sedimentological constraints. The new chronology is more regular than previously published records in large part due to new samples constraining the age of event R. The closed interval from event C to 1857 has a mean recurrence of 135years (?? = 83.2 years) and a quasiperiodic coefficient of variation (COV) of 0.61. We show that the new dates and resultant earthquake chronology have a stronger effect on COV than the specific membership of this long series and dating precision improvements from sedimentation rates. Copyright 2011 by the American Geophysical Union.

  19. Chronological dating and tectonic implications of late Cenozoic volcanic rocks and lacustrine sequence in Oiyug Basin of southern Tibet

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Reconstruction of uplift history of the Tibetan Plateau is crucial for understanding its environmental impacts. The Oiyug Basin in southern Tibet contains multiple periods of sedimentary sequences and volcanic rocks that span much of the Cenozoic and has great potential for further studying this issue. However, these strata were poorly dated. This paper presents a chronological study of the 145 m thick and horizontally-distributed lacustrine sequence using paleomagnetic method as well as a K-Ar dating of the underlying volcanic rocks. Based on these dating results, a chronostratigraphic framework and the basin-developmental history have been established for the past 15 Ma, during which three tectonic stages are identified. The period of 15-8.1 Ma is characterized by intense volcanic activities involving at least three major eruptions. Subsequently, the basin came into a tectonically quiescent period and a lacustrine sedimentary sequence was developed. Around 2.5 Ma, an N-S fault occurred across the southern margin of the basin, leading to the disappearance of the lake environment and the development of the Oiyug River. The Gyirong basin on northern slope of the Himalayas shows a similar basin developmental history and thus there is a good agreement in tectonic activities between the Himalayan and Gangdise orogenic belts. Therefore, the tectonic evolution stages experienced by the Oiyug Basin during the past 15 Ma could have a regional significance for southern Tibet. The chronological data obtained from this study may provide some constraints for further studies with regard to the tectonic processes and environmental changes in southern Tibetan Plateau.

  20. Seismic performance evaluation for super-long span cable-stayed bridges

    Institute of Scientific and Technical Information of China (English)

    Ye Aijun; Wu Shouchang

    2009-01-01

    Based on the capacity/demand (C/D) analysis of bridge components, and life cycle and performance based seismic design principles, a practical approach is developed for the seismic performance evaluation of super-long span cable-stayed bridges. According to the approach, the seismic performance evaluation of the Sutong Bridge, which is a cable-stayed bridge with a main span of 1 088 m, is completed, and the practicality of the approach is validated. The earthquake resistance level for super-long span cable-stayed bridges is discussed, including the earthquake level, its corresponding structural performance and check indices. And a set of formula for capacity/demand ratio calculation of bridge components is proposed.

  1. Spanning the Home/Work Creative Space

    DEFF Research Database (Denmark)

    Davis, Lee N.; Davis, Jerome; Hoisl, Karin

    This paper explores the link between employee leisure time activities and the value of their creative output. We argue that leisure time activities – both in general, and specifically with regard to the employee’s choice of hobbies – both illuminate and shape the attitudes and attributes the empl......This paper explores the link between employee leisure time activities and the value of their creative output. We argue that leisure time activities – both in general, and specifically with regard to the employee’s choice of hobbies – both illuminate and shape the attitudes and attributes...... the employee brings to work. Based on Woodman et al.’s (1993) “interactionist perspective” on organizational creativity, supplemented by literature on search and knowledge re/combination, we explore whether and how leisure time activities can span the creative space between the employee’s home and workplace...... – given the range of multi-level inputs that may also contribute to workplace creativity. We use original survey data comprising 4,138 inventions from 21 European countries, the United States and Japan, in all major industries. Organizational creativity is measured by the asset value of the patent...

  2. TimeSpan: Using Visualization to Explore Temporal Multi-dimensional Data of Stroke Patients.

    Science.gov (United States)

    Loorak, Mona Hosseinkhani; Perin, Charles; Kamal, Noreen; Hill, Michael; Carpendale, Sheelagh

    2016-01-01

    We present TimeSpan, an exploratory visualization tool designed to gain a better understanding of the temporal aspects of the stroke treatment process. Working with stroke experts, we seek to provide a tool to help improve outcomes for stroke victims. Time is of critical importance in the treatment of acute ischemic stroke patients. Every minute that the artery stays blocked, an estimated 1.9 million neurons and 12 km of myelinated axons are destroyed. Consequently, there is a critical need for efficiency of stroke treatment processes. Optimizing time to treatment requires a deep understanding of interval times. Stroke health care professionals must analyze the impact of procedures, events, and patient attributes on time-ultimately, to save lives and improve quality of life after stroke. First, we interviewed eight domain experts, and closely collaborated with two of them to inform the design of TimeSpan. We classify the analytical tasks which a visualization tool should support and extract design goals from the interviews and field observations. Based on these tasks and the understanding gained from the collaboration, we designed TimeSpan, a web-based tool for exploring multi-dimensional and temporal stroke data. We describe how TimeSpan incorporates factors from stacked bar graphs, line charts, histograms, and a matrix visualization to create an interactive hybrid view of temporal data. From feedback collected from domain experts in a focus group session, we reflect on the lessons we learned from abstracting the tasks and iteratively designing TimeSpan.

  3. Characterising the Welsh Roundhouse: chronology, inhabitation and landscape

    Directory of Open Access Journals (Sweden)

    Eleanor Ghey

    2007-11-01

    Full Text Available The article stems from a one-year project funded by the University of Wales Board of Celtic Studies to collect and analyse all the evidence for excavated prehistoric and early historic roundhouses in Wales. The resulting dataset will serve as a resource for researchers and, through the analysis provided in this article, provide an important counterpoint to similar studies from elsewhere in Britain. The methodology of the project is presented, and the limitations of the data are discussed in detail. The principal difficulties were associated with dating the building and duration of use of individual structures, and the bias created by a few sites with large numbers of excavated structures. The analysis and interpretation of the data is presented in three sections: chronology, inhabitation and landscape, and historical overview. The emphasis on recently excavated sites with good chronological control has enabled a more confident reconstruction of the history of roundhouse occupation in Wales. This has shown that while the architectural form has relatively early origins with numbers beginning to grow after 1500 BC, it is primarily a feature of first millennium BC and early first millennium AD landscapes. During the first millennium BC, timber- and stone-built settlements are common, initially as enclosed sites, and later, by the Roman period, as both open and enclosed settlements. This is contrary to the situation in many other parts of Britain, where roundhouses and frequently field systems are dated to at least the mid-second millennium BC onwards. There were strong regional differences between regions at this time, with for instance the predominance of stone- and clay-built sites in north-west Wales and the absence of Roman period roundhouses in the north-east. The dataset derived from the project will remain as an important resource with which to research these regional differences in greater detail and to examine the implications of new

  4. Heritability Estimates of Endophenotypes of Long and Health Life: The Long Life Family Study

    DEFF Research Database (Denmark)

    Matteini, Amy M; Fallin, M Daniele; Kammerer, Candace M;

    2010-01-01

    BACKGROUND: Identification of gene variants that contribute to exceptional survival may provide critical biologic information that informs optimal health across the life span. METHODS: As part of phenotype development efforts for the Long Life Family Study, endophenotypes that represent exception...

  5. Appearance and chronology of Textile ceramics in the Middle and Upper Volga region: critical comparison of conventional 14C-, AMS- and typological chronologies

    Directory of Open Access Journals (Sweden)

    Lavento Mika T.

    2015-06-01

    Full Text Available The article offers a comparison of three different methods of chronology construction – conventional 14C (radiocarbon dating, AMS (accelerator mass-spectrometry dating and the so called typological chronology – to date the textile ceramics of the Bronze – Early Iron Age in the Northern Coniferous Zone of Europe, from the Upper and Middle Volga and Kama Rivers to the Baltic region and Scandinavia. The Textile Ceramics Culture (also known as “Net”, “Pseudo-textile”, “Spun-and-speckled” is often associated with a Finnish-speaking community from the Bronze – beginning of the Iron Age. The earliest date of the Textile Ceramics sites on the Middle Oka River is presumably considered to be the 18 th century BC. Datings of the reference sites in the Middle Volga region were fixed within the 15 th – 8 th centuries BC. Comparing these data with the AMS chronology available for the materials from Finland and Estonia, the authors conclude that appearance of the Textile Ceramics was almost synchronous in the Volga and the Baltic regions, although chronology of the early tradition of the Textile Ceramics seems to be different in these areas. The results of yet a small number of AMS dates should be treated only as preliminary. However, AMS-dating seems to be the most efficient tool for further refining of the Textile Ceramics chronology over a vast territory, including in the Volga region.

  6. On the Chronological Structure of the Solutrean in Southern Iberia.

    Science.gov (United States)

    Cascalheira, João; Bicho, Nuno

    2015-01-01

    The Solutrean techno-complex has gained particular significance over time for representing a clear demographic and techno-typological deviation from the developments occurred during the course of the Upper Paleolithic in Western Europe. Some of Solutrean's most relevant features are the diversity and techno-typological characteristics of the lithic armatures. These have been recurrently used as pivotal elements in numerous Solutrean-related debates, including the chronological organization of the techno-complex across Iberia and Southwestern France. In Southern Iberia, patterns of presence and/or absence of specific point types in stratified sequences tend to validate the classical ordering of the techno-complex into Lower, Middle and Upper phases, although some evidence, namely radiocarbon determinations, have not always been corroborative. Here we present the first comprehensive analysis of the currently available radiocarbon data for the Solutrean in Southern Iberia. We use a Bayesian statistical approach from 13 stratified sequences to compare the duration, and the start and end moments of each classic Solutrean phase across sites. We conclude that, based on the current data, the traditional organization of the Solutrean cannot be unquestionably confirmed for Southern Iberia, calling into doubt the status of the classically-defined type-fossils as precise temporal markers.

  7. On the Chronological Structure of the Solutrean in Southern Iberia.

    Directory of Open Access Journals (Sweden)

    João Cascalheira

    Full Text Available The Solutrean techno-complex has gained particular significance over time for representing a clear demographic and techno-typological deviation from the developments occurred during the course of the Upper Paleolithic in Western Europe. Some of Solutrean's most relevant features are the diversity and techno-typological characteristics of the lithic armatures. These have been recurrently used as pivotal elements in numerous Solutrean-related debates, including the chronological organization of the techno-complex across Iberia and Southwestern France. In Southern Iberia, patterns of presence and/or absence of specific point types in stratified sequences tend to validate the classical ordering of the techno-complex into Lower, Middle and Upper phases, although some evidence, namely radiocarbon determinations, have not always been corroborative. Here we present the first comprehensive analysis of the currently available radiocarbon data for the Solutrean in Southern Iberia. We use a Bayesian statistical approach from 13 stratified sequences to compare the duration, and the start and end moments of each classic Solutrean phase across sites. We conclude that, based on the current data, the traditional organization of the Solutrean cannot be unquestionably confirmed for Southern Iberia, calling into doubt the status of the classically-defined type-fossils as precise temporal markers.

  8. Chronology protection in Galileon models and massive gravity

    Science.gov (United States)

    Burrage, Clare; de Rham, Claudia; Heisenberg, Lavinia; Tolley, Andrew J.

    2012-07-01

    Galileon models are a class of effective field theories that have recently received much attention. They arise in the decoupling limit of theories of massive gravity, and in some cases they have been treated in their own right as scalar field theories with a specific nonlinearly realized global symmetry (Galilean transformation). It is well known that in the presence of a source, these Galileon theories admit superluminal propagating solutions, implying that as quantum field theories they must admit a different notion of causality than standard local Lorentz invariant theories. We show that in these theories it is easy to construct closed timelike curves (CTCs) within the naive regime of validity of the effective field theory. However, on closer inspection we see that the CTCs could never arise since the Galileon inevitably becomes infinitely strongly coupled at the onset of the formation of a CTC. This implies an infinite amount of backreaction, first on the background for the Galileon field, signaling the break down of the effective field theory, and subsequently on the spacetime geometry, forbidding the formation of the CTC. Furthermore the background solution required to create CTCs becomes unstable with an arbitrarily fast decay time. Thus Galileon theories satisfy a direct analogue of Hawking's chronology protection conjecture.

  9. Chronological aging in conidia of pathogenic Aspergillus: Comparison between species.

    Science.gov (United States)

    Oliveira, Manuela; Pereira, Clara; Bessa, Cláudia; Araujo, Ricardo; Saraiva, Lucília

    2015-11-01

    Aspergillus fumigatus, Aspergillus flavus, Aspergillus terreus and Aspergillus niger are common airborne fungi, and the most frequent causative agents of human fungal infections. However, the resistance and lifetime persistence of these fungi in the atmosphere, and the mechanism of aging of Aspergillus conidia are unknown.With this work, we intended to study the processes underlying conidial aging of these four relevant and pathogenic Aspergillus species. Chronological aging was therefore evaluated in A. fumigatus, A. flavus, A. terreus and A. niger conidia exposed to environmental and human body temperatures. The results showed that the aging process in Aspergillus conidia involves apoptosis,with metacaspase activation, DNA fragmentation, and reactive oxygen species production, associated with secondary necrosis. Distinct results were observed for the selected pathogenic species. At environmental conditions, A. niger was the species with the highest resistance to aging, indicating a higher adaption to environmental conditions, whereas A. flavus followed by A. terreus were the most sensitive species. At higher temperatures (37 °C), A. fumigatus presented the longest lifespan, in accordance with its good adaptation to the human body temperature. Altogether,with this work new insights regarding conidia aging are provided, which may be useful when designing treatments for aspergillosis.

  10. Growth Culture Conditions and Nutrient Signaling Modulating Yeast Chronological Longevity

    Directory of Open Access Journals (Sweden)

    Júlia Santos

    2012-01-01

    Full Text Available The manipulation of nutrient-signaling pathways in yeast has uncovered the impact of environmental growth conditions in longevity. Studies using calorie restriction show that reducing glucose concentration of the culture media is sufficient to increase replicative and chronological lifespan (CLS. Other components of the culture media and factors such as the products of fermentation have also been implicated in the regulation of CLS. Acidification of the culture media mainly due to acetic acid and other organic acids production negatively impacts CLS. Ethanol is another fermentative metabolite capable of inducing CLS reduction in aged cells by yet unknown mechanisms. Recently, ammonium was reported to induce cell death associated with shortening of CLS. This effect is correlated to the concentration of NH4+ added to the culture medium and is particularly evident in cells starved for auxotrophy-complementing amino acids. Studies on the nutrient-signaling pathways regulating yeast aging had a significant impact on aging-related research, providing key insights into mechanisms that modulate aging and establishing the yeast as a powerful system to extend knowledge on longevity regulation in multicellular organisms.

  11. Holographic Protection of Chronology in Universes of the Godel Type

    Energy Technology Data Exchange (ETDEWEB)

    Boyda, Edward; Ganguli, Surya; Horava, Petr; Varadarajan, Uday

    2002-12-07

    We analyze the structure of supersymmetric Godel-like cosmological solutions of string theory. Just as the original four-dimensional Godel universe, these solutions represent rotating, topologically trivial cosmologies with a homogeneous metric and closed timelike curves. First we focus on"phenomenological" aspects of holography, and identify the preferred holographic screens associated with inertial comoving observers in Godel universes. We find that holography can serve as a chronology protection agency: The closed timelike curves are either hidden behind the holographic screen, or broken by it into causal pieces. In fact, holography in Godel universes has many features in common with de Sitter space, suggesting that Godel universes could represent a supersymmetric laboratory for addressing the conceptual puzzles of de Sitter holography. Then we initiate the investigation of"microscopic" aspects of holography of Godel universes in string theory. We show that Godel universes are T-dual to pp-waves, and use this fact to generate new Godel-like solutions of string and M-theory by T-dualizing known supersymmetric pp-wave solutions.

  12. Molecular biomarkers for chronological age in animal ecology.

    Science.gov (United States)

    Jarman, Simon N; Polanowski, Andrea M; Faux, Cassandra E; Robbins, Jooke; De Paoli-Iseppi, Ricardo; Bravington, Mark; Deagle, Bruce E

    2015-10-01

    The chronological age of an individual animal predicts many of its biological characteristics, and these in turn influence population-level ecological processes. Animal age information can therefore be valuable in ecological research, but many species have no external features that allow age to be reliably determined. Molecular age biomarkers provide a potential solution to this problem. Research in this area of molecular ecology has so far focused on a limited range of age biomarkers. The most commonly tested molecular age biomarker is change in average telomere length, which predicts age well in a small number of species and tissues, but performs poorly in many other situations. Epigenetic regulation of gene expression has recently been shown to cause age-related modifications to DNA and to cause changes in abundance of several RNA types throughout animal lifespans. Age biomarkers based on these epigenetic changes, and other new DNA-based assays, have already been applied to model organisms, humans and a limited number of wild animals. There is clear potential to apply these marker types more widely in ecological studies. For many species, these new approaches will produce age estimates where this was previously impractical. They will also enable age information to be gathered in cross-sectional studies and expand the range of demographic characteristics that can be quantified with molecular methods. We describe the range of molecular age biomarkers that have been investigated to date and suggest approaches for developing the newer marker types as age assays in nonmodel animal species.

  13. Reliability of panoramic radiography in chronological age estimation

    Directory of Open Access Journals (Sweden)

    Ramanpal Singh Makkad

    2013-01-01

    Full Text Available Introduction: There has been a strong relationship between the growth rate of bone and teeth, which can be utilized for the purpose of age identification of an individual. Aims and Objective: The present study was designed to determine the relationship between the dental age, the age from dental panoramic radiography, skeletal age, and chronological age. Materials and Methods: The study included 270 individuals, averaging between 17 years and 25 years of age from out-patient department of New Horizon Dental College and Hospital, Sakri, Bilaspur, Chhattisgarh, India, for third molar surgery. Panoramic and hand wrist radiographs were taken, the films were digitally processed for visualization of the wisdom teeth. The confirmations of ages were repeated again at an interval of 4 weeks by a radiologist. The extracted wisdom teeth were placed in 10% formalin and were examined by one dental surgeon to estimate the age on the basis of root formation. Student′s t-test was adopted for statistical analysis and probability (P value was calculated. Conclusion: Estimating the age of an individual was accurate by examining extracted third molar. Age estimation through panoramic radiography was highly accurate in upper right quadrant (mean = 0.72 and P = 0.077.

  14. Estimation of Chronological Age According to Risser’s Sign

    Directory of Open Access Journals (Sweden)

    Sh. Birang

    2008-10-01

    Full Text Available Background/Objective: Risser's sign, a measure of excursion in the iliac crest apophysis, has been used to evaluate the remaining skeletal growth. The objective of this study was to evaluate the value of Risser's sign in estimation of chronological age in a number of university-affiliated referral hospitals in Tehran, Iran."nPatients and Methods: Our study group consisted of 206 patients aged between 10 and 25 years with a stable hemodynamic condition who were referred due to trauma in regions other than the head and neck. All cases underwent AP spine and proximal pelvis radiographies. All radiographies were graded by Risser's scoring system."nResults: Among our patients, 121 (58.6% were male and 85 (41.3% were female. Risser's score of 0, 1, 2, 3, 4 and 5 were seen in 13 (6.3%, 7 (3.4%, 24 (11.7%, 48 (23.3%, 35 (17%, and 79 (38.3% of the patients, respectively. Risser's score was determined for all age groups. All cases aged over 18 years had a Risser's score ≥3."nConclusion: Risser's score is useful for the estimation of age in adults especially for legal purposes, though further multicenter studies are required for more comprehensive and precise data of the normal Iranian population.

  15. The chronology of third molar mineralization by digital orthopantomography.

    Science.gov (United States)

    Maled, Venkatesh; Vishwanath, S B

    2016-10-01

    The present study was designed to determine the chronology of third molar mineralization to establish Indian reference data and to observe the advantages of digital orthopantomography. Therefore, a cross-sectional study was undertaken by evaluating 167 digital orthopantomographs in order to assess the mineralization status of the mandibular third molar of Caucasian individuals (85 males and 82 females) between the age of 14 and 24. The evaluation was carried out using the 8-stage developmental scheme of Demirjian et al (1973). The range, mean age, standard deviation and Student t-test are presented for each stage of mineralization in all four quadrants. Statistically significant differences between males and females were not found for all four third molars. All the individuals in this study with mature third molar were at least 18 years of age. For medicolegal purposes, the likelihood of whether an Indian is older than 18 years or not was determined. The advantage of digital orthopantomography in the interpretation of the tooth mineralization over the traditional method was acknowledged.

  16. The life and work of Gustav Elfving

    OpenAIRE

    Nordström, Kenneth

    1999-01-01

    This article outlines the scientific work and life of the Finnish statistician, probabilist, and mathematician Gustav Elfving (1908–1984). Elfving’s academic career, scientific contacts, and personal life are sketched, and his main research contributions to the fields of statistics, probability, and mathematics are reviewed. (Elfving’s pioneering work in optimal design of experiments is not covered, as this topic will be treated elsewhere in this issue.) A chronological bibl...

  17. Sediment accumulation, stratigraphic order, and the extent of time-averaging in lagoonal sediments: a comparison of 210Pb and 14C/amino acid racemization chronologies

    Science.gov (United States)

    Kosnik, Matthew A.; Hua, Quan; Kaufman, Darrell S.; Zawadzki, Atun

    2015-03-01

    Carbon-14 calibrated amino acid racemization (14C/AAR) data and lead-210 (210Pb) data are used to examine sediment accumulation rates, stratigraphic order, and the extent of time-averaging in sediments collected from the One Tree Reef lagoon (southern Great Barrier Reef, Australia). The top meter of lagoonal sediment preserves a stratigraphically ordered deposit spanning the last 600 yrs. Despite different assumptions, the 210Pb and 14C/AAR chronologies are remarkably similar indicating consistency in sedimentary processes across sediment grain sizes spanning more than three orders of magnitude (0.1-10 mm). Estimates of long-term sediment accumulation rates range from 2.2 to 1.2 mm yr-1. Molluscan time-averaging in the taphonomically active zone is 19 yrs, whereas below the depth of final burial (~15 cm), it is ~110 yrs/5 cm layer. While not a high-resolution paleontological record, this reef lagoon sediment is suitable for paleoecological studies spanning the period of Western colonization and development. This sedimentary deposit, and others like it, should be useful, albeit not ideal, for quantifying anthropogenic impacts on coral reef systems.

  18. Spanning Trees and bootstrap reliability estimation in correlation based networks

    CERN Document Server

    Tumminello, M; Lillo, F; Micciché, S; Mantegna, R N

    2006-01-01

    We introduce a new technique to associate a spanning tree to the average linkage cluster analysis. We term this tree as the Average Linkage Minimum Spanning Tree. We also introduce a technique to associate a value of reliability to links of correlation based graphs by using bootstrap replicas of data. Both techniques are applied to the portfolio of the 300 most capitalized stocks traded at New York Stock Exchange during the time period 2001-2003. We show that the Average Linkage Minimum Spanning Tree recognizes economic sectors and sub-sectors as communities in the network slightly better than the Minimum Spanning Tree does. We also show that the average reliability of links in the Minimum Spanning Tree is slightly greater than the average reliability of links in the Average Linkage Minimum Spanning Tree.

  19. Global surface temperature signals in pine ring-width chronologies from southern monsoon Asia

    Science.gov (United States)

    Buckley, B. M.; Cook, B. I.; Bhattacharyya, A.; Dukpa, D.; Chaudhary, V.

    2005-10-01

    We analyze Pinus ring width chronologies from three locations across monsoon Asia (Bhutan, India, and Thailand) where climate is dominated by the southwest monsoon in the boreal summer. We compare these records to global surface temperatures for the past 150 years, shifting the correlations through three seasonal averages: two seasons preceding the monsoon (Dec-Feb and Mar-May), and the monsoon season itself (Jun-Sep). Clear patterns emerge for each of the chronologies that highlight links to areas of known influence on the Asian monsoon: the Indian Ocean, the tropical eastern Pacific Ocean, and the high-latitude Asian landmass. The Thai and Indian chronologies are from the same species (P. merkusii), and show a strong correlation with tropical Indian and Pacific Ocean bands. The Bhutan chronology (P. Wallichiana) is most strongly linked to climate over the north Pacific and Asian landmass. All of these correlations are strongest in seasons preceding the summer monsoon.

  20. Birds of Buldir Island, Alaska with notes on abundance and nesting chronology

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The purpose of the study was to evaluate nesting chronologies, population sizes, and habitat utilization of birds, particularly Aleutian Canada Geese (Branta...

  1. Developmental Changes in the Visual Span for Reading

    OpenAIRE

    Kwon, MiYoung; Legge, Gordon E; Dubbels, Brock R.

    2007-01-01

    The visual span for reading refers to the range of letters, formatted as in text, that can be recognized reliably without moving the eyes. It is likely that the size of the visual span is determined primarily by characteristics of early visual processing. It has been hypothesized that the size of the visual span imposes a fundamental limit on reading speed (Legge, Mansfield, & Chung, 2001). The goal of the present study was to investigate developmental changes in the size of the visual span i...

  2. MINIMUM CONGESTION SPANNING TREES IN BIPARTITE AND RANDOM GRAPHS

    Institute of Scientific and Technical Information of China (English)

    M.L Ostrovskii

    2011-01-01

    The first problem considered in this article reads: is it possible to find upper estimates for the spanning tree congestion in bipartite graphs, which are better than those for general graphs? It is proved that there exists a bipartite version of the known graph with spanning tree congestion of order n3/2, where n is the number of vertices. The second problem is to estimate spanning tree congestion of random graphs. It is proved that the standard model of random graphs cannot be used to find graphs whose spanning tree congestion has order greater than n3/2.

  3. Contributions of dynamic environmental signals during life-cycle transitions to early life-history traits in lodgepole pine (Pinus contorta Dougl.)

    Science.gov (United States)

    Liu, Yang; Wang, Tongli; El-Kassaby, Yousry A.

    2016-05-01

    Environmental signals are important triggers in the life-cycle transitions and play a crucial role in the life-history evolution. Yet very little is known about the leading ecological factors contributing to the variations of life-history traits in perennial plants. This paper explores both the causes and consequences for the evolution of life-history traits (i.e., seed dormancy and size) in lodgepole pine (Pinus contorta Dougl.) across British Columbia (B.C.), Canada. We selected 83 logepole pine populations covering 22 ecosystem zones of B.C. and through their geographic coordinate, 197 climatic variables were generated accordingly for the reference (1961-1990) and future (2041-2070) periods. We found that dynamic climatic variables rather than constant geographic variables are the true environmental driving forces in seed dormancy and size variations and thus provide reliable predictors in response to global climate change. Evapotranspiration and precipitation in the plant-to-seed chronology are the most critical climate variables for seed dormancy and size variations, respectively. Hence, we predicted that levels of seed dormancy in lodgepole pine would increase across large tracts of B.C. in 2050s. Winter-chilling is able to increase the magnitude of life-history plasticity and lower the bet-hedge strategy in the seed-to-plant transition; however, winter-chilling is likely to be insufficient in the north of 49° N in 2050s, which may delay germination while unfavorable conditions during dry summers may result in adverse consequences in the survival of seedlings owing to extended germination span. These findings provide useful information to studies related to assessments of seed transfer and tree adaptation.

  4. Quantitative and Qualitative Approaches to Identifying Migration Chronology in a Continental Migrant

    OpenAIRE

    Beatty, William S.; Dylan C Kesler; Elisabeth B Webb; Andrew H Raedeke; Naylor, Luke W.; Humburg, Dale D.

    2013-01-01

    The degree to which extrinsic factors influence migration chronology in North American waterfowl has not been quantified, particularly for dabbling ducks. Previous studies have examined waterfowl migration using various methods, however, quantitative approaches to define avian migration chronology over broad spatio-temporal scales are limited, and the implications for using different approaches have not been assessed. We used movement data from 19 female adult mallards (Anas platyrhynchos) eq...

  5. Nutrient Limitation of Microbial Mediated Decomposition and Arctic Soil Chronology

    Science.gov (United States)

    Melle, C. J.; Darrouzet-Nardi, A.; Wallenstein, M. D.

    2012-12-01

    Soils of northern permafrost regions currently contain twice as much carbon as the entire Earth's atmosphere. Traditionally, environmental constraints have limited microbial activity resulting in restricted decomposition of soil organic matter in these systems and accumulation of massive amounts of soil organic carbon (SOC), however climate change is reducing the constraints of decomposition in arctic permafrost regions. Carbon cycling in nutrient poor, arctic ecosystems is tightly coupled to other biogeochemical cycles. Several studies have suggested strong nitrogen limitations of primary productivity and potentially warm-season microbial activity in these nutrient deficient soils. Nitrogen is required for microbial extracellular enzyme production which drives the decomposition of soil organic matter (SOM). Nitrogen limited arctic soils may also experience limitation via labile carbon availability despite the SOM rich environment due to low extracellular enzyme production. Few studies have directly addressed nutrient induced microbial limitation in SOC rich arctic tundra soils, and even less is known about the potential for nutrient co-limitation. Additionally, through the process of becoming deglaciated, sites within close proximity to one another may have experienced drastic differences in their effective soil ages due to the varied length of their active histories. Many soil properties and nutrient deficiencies are directly related to soil age, however this chronology has not previously been a focus of research on nutrient limitation of arctic soil microbial activity. Understanding of nutrient limitations, as well as potential co-limitation, on arctic soil microbial activity has important implications for carbon cycling and the ultimate fate of the current arctic SOC reservoir. Analyses of nutrient limitation on soils of a single site are not adequate for fully understanding the controls on soil microbial activity across a vast land mass with large variation in

  6. A 60 000 year Greenland stratigraphic ice core chronology

    Directory of Open Access Journals (Sweden)

    K. K. Andersen

    2007-11-01

    Full Text Available The Greenland Ice Core Chronology 2005 (GICC05 is a time scale based on annual layer counting of high-resolution records from Greenland ice cores. Whereas the Holocene part of the time scale is based on various records from the DYE-3, the GRIP, and the NorthGRIP ice cores, the glacial part is solely based on NorthGRIP records. Here we present an 18 kyr extension of the time scale such that GICC05 continuously covers the past 60 kyr. The new section of the time scale places the onset of Greenland Interstadial 12 (GI-12 at 46.9±1.0 kyr b2k (before year AD 2000, the North Atlantic Ash Zone 2 layer in GI-15 at 55.4±1.2 kyr b2k, and the onset of GI-17 at 59.4±1.3 kyr b2k. The error estimates are derived from the accumulated number of uncertain annual layers and can be regarded as 1σ uncertainties. In the 40–60 kyr interval the new time scale has a discrepancy with the Meese-Sowers GISP2 time scale of up to 2.4 kyr, whereas GICC05 compares well to the dating of the Hulu Cave record with absolute age differences of less than 800 years throughout the 60 kyr period. The new time scale is generally in close agreement with other independently dated records and reference horizons, such as the Laschamp geomagnetic excursion and the Kleegruben speleothem record from the Austrian Alps, suggesting high accuracy of both event durations and absolute age estimates.

  7. A 60 000 year Greenland stratigraphic ice core chronology

    Directory of Open Access Journals (Sweden)

    A. Svensson

    2008-03-01

    Full Text Available The Greenland Ice Core Chronology 2005 (GICC05 is a time scale based on annual layer counting of high-resolution records from Greenland ice cores. Whereas the Holocene part of the time scale is based on various records from the DYE-3, the GRIP, and the NorthGRIP ice cores, the glacial part is solely based on NorthGRIP records. Here we present an 18 ka extension of the time scale such that GICC05 continuously covers the past 60 ka. The new section of the time scale places the onset of Greenland Interstadial 12 (GI-12 at 46.9±1.0 ka b2k (before year AD 2000, the North Atlantic Ash Zone II layer in GI-15 at 55.4±1.2 ka b2k, and the onset of GI-17 at 59.4±1.3 ka b2k. The error estimates are derived from the accumulated number of uncertain annual layers. In the 40–60 ka interval, the new time scale has a discrepancy with the Meese-Sowers GISP2 time scale of up to 2.4 ka. Assuming that the Greenland climatic events are synchronous with those seen in the Chinese Hulu Cave speleothem record, GICC05 compares well to the time scale of that record with absolute age differences of less than 800 years throughout the 60 ka period. The new time scale is generally in close agreement with other independently dated records and reference horizons, such as the Laschamp geomagnetic excursion, the French Villars Cave and the Austrian Kleegruben Cave speleothem records, suggesting high accuracy of both event durations and absolute age estimates.

  8. Chronology of Awareness About US National Park External Threats

    Science.gov (United States)

    Shafer, Craig L.

    2012-12-01

    The objective of this paper is to raise understanding of the history of protected area external threat awareness in the United States and at World Protected Area Congresses. The earliest concerns about external threats to US national parks began in the late nineteenth century: a potential railroad transgression of Yellowstone National Park in the 1880s. During the early and mid 1930s, George Wright and colleagues focused on outside boundary concerns like of hunting and trapping of furbearers, grazing, logging, disease and hybridization between species. In the 1960s, a worldwide recognition began about the role of outside habitat fragmentation/isolation on nature reserves and human generated stressors crossing their boundaries. The State of the Park Report 1980 added a plethora of threats: oil/gas and geothermal exploration and development, hydropower and reclamation projects, urban encroachment, roads, resorts, and recreational facilities. The early 1980s ushered in political interference with NPS threats abatement efforts as well as Congressional legislative initiatives to support the abatement challenges of the agency. By 1987, the Government Accounting Office issued its first report on National Park Service (NPS) progress in dealing with external threats. Climate change impacts on parks, especially in terms of animals adjusting their temperature and moisture requirements by latitude and altitude, surfaced in the technical literature by the mid-1980s. By 1992, the world parks community stressed the need to integrate protected areas into the surrounding landscape and human community. The importance of the matrix has gradually gained appreciation in the scientific community. This chronology represents one example of national park and protected areas' institutional history contributing to the breath of modern conservation science.

  9. On the Assimilation of Tree-Ring-Width Chronologies

    Science.gov (United States)

    Acevedo, Walter; Reich, Sebastian; Cubasch, Ulrich

    2015-04-01

    Data assimilation (DA) of climate proxy records is currently acknowledged as a promising approach to the paleoclimate reconstruction problem, with the potential to bring physical consistency to reconstructed fields. Previous paleo-DA studies have typically assumed a linear relationship between climate forcing and the resulting proxy data, whereas there exist growing evidence of complex, potentially non-linear, proxy formation processes. Accordingly, it appears natural to simulate the proxy response to climate in a more realistic fashion, by way of proxy-specific forward models. Following this train of thought, we investigate the assimilation of the most traditional climate proxy type, Tree-Ring-Width (TRW) chronologies, using the process-based tree-ring growth forward model Vaganov-Shashkin-Lite (VSL) and ensemble Kalman filter (EnKF) techniques. Used as observation operator, VSL's formulation implies three compounding, challenging features: (i) time averaging, (ii) "switching recording" of 2 variables and (iii) bounded response windows leading to "thresholded response". DA experiments involving VSL-based pseudo-TRW observations are performed first for a chaotic 2-scale dynamical system, used as a cartoon of the atmosphere-land system, and then for an atmospheric general circulation model of intermediate complexity. Our results reveal that VSL's nonlinearities may considerable deteriorate the performance of EnKF for Time-Averaged (TA) estimation, as compared to the utilization of a TA linear observation operator. Moreover, we show that this assimilation skill loss can be considerably reduced by embedding VSL's formulation into fuzzy logic theory, which fosters new interpretations of tree-ring growth limitation processes.

  10. Application of Bomb Radiocarbon Chronologies to Shortfin Mako (Isurus oxyrinchus)

    Energy Technology Data Exchange (ETDEWEB)

    Ardizzone, D; Cailliet, G M; Natanson, L J; Andrews, A H; Kerr, L A; Brown, T A

    2007-07-16

    and the number of samples for MIA analysis was insufficient for some months. Hence, unequivocal validation of shortfin mako age estimates has yet to be accomplished. Atmospheric testing of thermonuclear devices in the 1950s and 1960s effectively doubled the natural atmospheric radiocarbon ({sup 14}C). The elevated {sup 14}C levels were first recorded in 1957-58, with a peak around 1963. As a consequence, {sup 14}C entered the ocean through gas exchange with the atmosphere at the ocean surface and in terrestrial runoff. Despite variable oceanographic conditions, a worldwide rise of the bomb {sup 14}C signal entered the ocean mixed layer as dissolved inorganic carbon (DIC) in 1957-58. The large amounts of {sup 14}C released from the bomb tests produced a signature that can be followed through time, throughout the marine food web, and into deeper waters. The marked increase of radiocarbon levels was first measured in the DIC of seawater and in biogenic marine carbonates of hermatypic corals in Florida. Subsequently, this record was documented in corals from other regions and in the thallus of rhodoliths. The accumulation of radiocarbon in the hard parts of most marine organisms in the mixed layer (such as fish otoliths and bivalves) was synchronous with the coral time-series. This technique has been used to validate age estimates and longevity of numerous bony fishes to date, as well as to establish bomb radiocarbon chronologies from different oceans. In the first application of this technique to lamnoid sharks, validated annual band-pair deposition in vertebral growth bands for the porbeagle (Lamna nasus) aged up to 26 years. Radiocarbon values from samples obtained from 15 porbeagle caught in the western North Atlantic Ocean (some of which were known-age) produced a chronology similar in magnitude to the reference carbonate chronology for that region. The observed phase shift of about 3 years was attributed to different sources of carbon between vertebrae and those for

  11. Application of Bomb Radiocarbon Chronologies to Shortfin Mako (Isurus oxyrinchus)

    Energy Technology Data Exchange (ETDEWEB)

    Ardizzone, D; Cailliet, G M; Natanson, L J; Andrews, A H; Kerr, L A; Brown, T A

    2007-07-16

    and the number of samples for MIA analysis was insufficient for some months. Hence, unequivocal validation of shortfin mako age estimates has yet to be accomplished. Atmospheric testing of thermonuclear devices in the 1950s and 1960s effectively doubled the natural atmospheric radiocarbon ({sup 14}C). The elevated {sup 14}C levels were first recorded in 1957-58, with a peak around 1963. As a consequence, {sup 14}C entered the ocean through gas exchange with the atmosphere at the ocean surface and in terrestrial runoff. Despite variable oceanographic conditions, a worldwide rise of the bomb {sup 14}C signal entered the ocean mixed layer as dissolved inorganic carbon (DIC) in 1957-58. The large amounts of {sup 14}C released from the bomb tests produced a signature that can be followed through time, throughout the marine food web, and into deeper waters. The marked increase of radiocarbon levels was first measured in the DIC of seawater and in biogenic marine carbonates of hermatypic corals in Florida. Subsequently, this record was documented in corals from other regions and in the thallus of rhodoliths. The accumulation of radiocarbon in the hard parts of most marine organisms in the mixed layer (such as fish otoliths and bivalves) was synchronous with the coral time-series. This technique has been used to validate age estimates and longevity of numerous bony fishes to date, as well as to establish bomb radiocarbon chronologies from different oceans. In the first application of this technique to lamnoid sharks, validated annual band-pair deposition in vertebral growth bands for the porbeagle (Lamna nasus) aged up to 26 years. Radiocarbon values from samples obtained from 15 porbeagle caught in the western North Atlantic Ocean (some of which were known-age) produced a chronology similar in magnitude to the reference carbonate chronology for that region. The observed phase shift of about 3 years was attributed to different sources of carbon between vertebrae and those for

  12. Chinese pine tree ring width chronology and its relation to climate conditions in the Qianshan Mountains

    Institute of Scientific and Technical Information of China (English)

    Zhenju CHEN; Yu SUN; Xingyuan HE; Wei CHEN; Xuemei SHAO; Huayu ZHANG; Zhongyu WANG; Xiaoyu LIU

    2008-01-01

    Taking Chinese pine in Qianshan Mountains as a sample, the tree ring width chronology including Standard, Residual, and Arstan chronologies was estab-lished. The results show that the tree ring width of Chinese pine is highly correlated with the temperatures from May to July and from September to November. Statistically significant positive correlations were observed between tree ring width and the extreme minimum temperatures in July and mean minimum temperatures in September. The chronology was significantly or very significantly correlated with extreme minimum temperatures in December and the following January, with mean min-imum temperatures in January, with annual precipita-tion and with precipitation in April, May and the following December. The Chinese pine responded strongly to the monthly/yearly water vapor pressure and relative humidity. Annual and largely monthly evaporation in April-July had a negative effect on tree growth, and was particularly striking for evaporation in April-July. The narrow tree rings recorded by the chro-nology demonstrated the 30 occasions of extreme drought since 1800. The growth of ChineSe pine in the Qianshan mountains were also affected by climate changes on a hemispheric and global scale. There were 11-, 23-and 50-year-common periodicities between the chronology and solar activity and 10-, 20- and 45-year-common periodicit-ies between the chronology and geomagnetic activity.

  13. The use of passwords to introduce theconcepts of spanning set and span

    Directory of Open Access Journals (Sweden)

    Andrea Cárcamo

    2017-01-01

    Full Text Available The aim of this paper is to present a proposal for teaching linear algebra based on heuristic of emergent models and mathematical modelling. This proposal begins with a problematic situation  related  to  the  creation  and  use  of  secure  passwords,  which  leads  first-year  students  of  engineering  toward  the  construction  of  the  concepts  of  spanning  set  and  span. The  proposal  is  designed  from  the  results  of  the  two  cycles  of  experimentation  teaching, design-based  research,  which  give  evidence  that  allows  students  to  progress  from  a  situation in a real context to the concepts of linear algebra. This proposal, previously adapted, could have similar results when applied to another group of students.

  14. 23 CFR 650.809 - Movable span bridges.

    Science.gov (United States)

    2010-04-01

    ... 23 Highways 1 2010-04-01 2010-04-01 false Movable span bridges. 650.809 Section 650.809 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION ENGINEERING AND TRAFFIC OPERATIONS BRIDGES, STRUCTURES, AND HYDRAULICS Navigational Clearances for Bridges § 650.809 Movable span bridges. A fixed...

  15. Community Engagement and Boundary-Spanning Roles at Research Universities

    Science.gov (United States)

    Weerts, David J.; Sandmann, Lorilee R.

    2010-01-01

    Over the past decade, community engagement has emerged as an important priority among many colleges and universities. This study employs a multi-case study design to examine boundary spanning practices of research universities that have adopted a community engagement agenda. A model is advanced to conceptualize spanning behaviors and to inform…

  16. Measuring Boundary-Spanning Behaviors in Community Engagement

    Science.gov (United States)

    Sandmann, Lorilee R.; Jordan, Jenny W.; Mull, Casey D.; Valentine, Thomas

    2014-01-01

    Community engagement professionals and partners serve as, work with, study, and build the capacity of boundary spanners. To augment knowledge about these functions, the Weerts-Sandmann Boundary Spanning Conceptual Framework (2010) has been operationalized through a survey instrument to examine community engagement boundary-spanning behaviors by…

  17. The Effect of Orthographic Neighborhood in the Reading Span Task

    Science.gov (United States)

    Robert, Christelle; Postal, Virginie; Mathey, Stéphanie

    2015-01-01

    This study aimed at examining whether and to what extent orthographic neighborhood of words influences performance in a working memory span task. Twenty-five participants performed a reading span task in which final words to be memorized had either no higher frequency orthographic neighbor or at least one. In both neighborhood conditions, each…

  18. Development of the perceptual span in reading: A longitudinal study.

    Science.gov (United States)

    Sperlich, Anja; Meixner, Johannes; Laubrock, Jochen

    2016-06-01

    The perceptual span is a standard measure of parafoveal processing, which is considered highly important for efficient reading. Is the perceptual span a stable indicator of reading performance? What drives its development? Do initially slower and faster readers converge or diverge over development? Here we present the first longitudinal data on the development of the perceptual span in elementary school children. Using the moving window technique, eye movements of 127 German children in three age groups (Grades 1, 2, and 3 in Year 1) were recorded at two time points (T1 and T2) 1 year apart. Introducing a new measure of the perceptual span, nonlinear mixed-effects modeling was used to separate window size effects from asymptotic reading performance. Cross-sectional differences were well replicated longitudinally. Asymptotic reading rate increased monotonously with grade, but in a decelerating fashion. A significant change in the perceptual span was observed only between Grades 2 and 3. Together with results from a cross-lagged panel model, this suggests that the perceptual span increases as a consequence of relatively well-established word reading. Stabilities of observed and predicted reading rates were high after Grade 1, whereas the perceptual span was only moderately stable for all grades. Comparing faster and slower readers as assessed at T1, in general, a pattern of stable between-group differences emerged rather than a compensatory pattern; second and third graders even showed a Matthew effect in reading rate and the perceptual span, respectively.

  19. Aerodynamic challenges in span length of suspension bridges

    Institute of Scientific and Technical Information of China (English)

    XIANG Haifan; GE Yaojun

    2007-01-01

    The potential requirement of extreme bridge spans is firstly discussed according to horizontal clearances for navigation and economical construction of deep-water foundation. To ensure the technological feasibility of suspen- sion bridges with longer spans, the Static estimation of feasi- ble span length is then made based on current material strength and weight of cables and deck. After the performances of the countermeasures for raising the aerodynamic stability are reviewed, a trial design of a 5 000 m suspension bridge, which is estimated as a reasonable limitation of span length, is finally conducted to respond to the tomorrow's challenge in span length of suspension bridges with the particular aspects, including dynamic stiffness, aerodynamic flutter and aerostatic stability.

  20. Power, Governance and Boundary Spanning Leadership in Public Sector Organisations

    DEFF Research Database (Denmark)

    Elmholdt, Claus Westergård; Fogsgaard, Morten

    2015-01-01

    in public sector organizations. This research project has, among other things, highlighted the ways in which boundary spanning leadership can be related to establishing a shared pool of actions, knowledge, communication, trust and identity in the organization. Furthermore, the research project stresses......The phenomenon of power and boundary spanning leadership in public sector organizations is the topic for the present workshop. In this workshop we present a practice perspective (Corradi, Gherardi and Verzelloni 2010) on the management of power and boundary spanning leadership. We will focus...... on the practice that evolves on the boundaries that span occupational groups, departments and organizations. The workshop takes it’s starting point in an interdisciplinary Scandinavian research project which deals with the question of how power processes can promote, or hinder, boundary spanning leadership...

  1. Structural health monitoring of long-span suspension bridges using wavelet packet analysis

    Institute of Scientific and Technical Information of China (English)

    Ding Youliang; Li Aiqun

    2007-01-01

    During the service life of civil engineering structures such as long-span bridges, local damage at key positions may continually accumulate, and may finally result in their sudden failure. One core issue of global vibration-based health monitoring methods is to seek some damage indices that are sensitive to structural damage. This paper proposes an online structural health monitoring method for long-span suspension bridges using wavelet packet transform (WPT). The WPTbased method is based on the energy variations of structural ambient vibration responses decomposed using wavelet packet analysis. The main feature of this method is that the proposed wavelet packet energy spectrum (WPES) has the ability to detect structural damage from ambient vibration tests of a long-span suspension bridge. As an example application, the WPES-based health monitoring system is used on the Runyang Suspension Bridge under daily environmental conditions. The analysis reveals that changes in environmental temperature have a long-term influence on the WPES, while the effect of traffic loadings on the measured WPES of the bridge presents instantaneous changes because of the nonstationary properties of the loadings. The condition indication indices VD reflect the influences of environmental temperature on the dynamic properties of the Runyang Suspension Bridge. The field tests demonstrate that the proposed WPES-based condition indication index VD is a good candidate index for health monitoring of long-span suspension bridges under ambient excitations.

  2. Structural health monitoring of long-span suspension bridges using wavelet packet analysis

    Science.gov (United States)

    Ding, Youliang; Li, Aiqun

    2007-09-01

    During the service life of civil engineering structures such as long-span bridges, local damage at key positions may continually accumulate, and may finally result in their sudden failure. One core issue of global vibration-based health monitoring methods is to seek some damage indices that are sensitive to structural damage. This paper proposes an online structural health monitoring method for long-span suspension bridges using wavelet packet transform (WPT). The WPT-based method is based on the energy variations of structural ambient vibration responses decomposed using wavelet packet analysis. The main feature of this method is that the proposed wavelet packet energy spectrum (WPES) has the ability to detect structural damage from ambient vibration tests of a long-span suspension bridge. As an example application, the WPES-based health monitoring system is used on the Runyang Suspension Bridge under daily environmental conditions. The analysis reveals that changes in environmental temperature have a long-term influence on the WPES, while the effect of traffic loadings on the measured WPES of the bridge presents instantaneous changes because of the nonstationary properties of the loadings. The condition indication indices V D reflect the influences of environmental temperature on the dynamic properties of the Runyang Suspension Bridge. The field tests demonstrate that the proposed WPES-based condition indication index V D is a good candidate index for health monitoring of long-span suspension bridges under ambient excitations.

  3. A new luminescence dating chronology for the Rhafas cave site (NE Morocco): Insights into Palaeolithic human cultural change under varying palaeoenvironmental conditions in the Maghreb

    Science.gov (United States)

    Dörschner, Nina; Fitzsimmons, Kathryn E.; Ditchfield, Peter; McLaren, Sue J.; Steele, Teresa E.; Zielhofer, Christoph; McPherron, Shannon P.; Bouzouggar, Abdeljalil; Hublin, Jean-Jacques

    2016-04-01

    Archaeological sites in northern Africa provide a rich record that is of increasing importance for current debates relating to the origins of modern human behaviour and to Out of Africa human dispersal events. Particular interest is placed on the cultural transition between the North African Middle Stone Age (MSA) and Late Stone Age (LSA), and the need for accurately defined chronologies, however the timing and nature of Palaeolithic human behaviour and dispersal across north-western Africa (the Maghreb) and potential correlation with environmental conditions remain poorly understood. The inland cave site of Rhafas (Morocco) preserves a long stratified sequence providing valuable chronological information about cultural changes in the Maghreb spanning the North African MSA through to the Neolithic. In this study, we apply optically stimulated luminescence (OSL) dating on sand-sized quartz grains to the cave deposits of Rhafas as well as to a section on the terrace in front of the cave entrance. Single grain OSL dating reliably constrains the timing of technocomplexes beyond the limits of radiocarbon by directly dating sediment associated with archaeological traces. We combine OSL dating with multi-proxy geological investigations (XRF, grain size analyses, stable isotopes, thin sections) to investigate site formation processes and reconstruct palaeoenvironmental conditions during human occupation phases at Rhafas. Our results indicate that the occupation of the site started at least in MIS 6 during a phase of relatively arid environmental conditions. Climatic amelioration after c.140 ka is associated with a change in sediment geochemistry at the site, most likely linked to a change in sediment source due to shifting wind directions. Tanged pieces - typical for the classical Aterian technocomplex - start to occur in the archaeological sequence in MIS 5, consistent with previously published chronological data from the Maghreb. From 55 ka, climatic conditions were

  4. Bilinear slack span calculation model. Slack span calculations for high-temperature cables; Bilineares Berechnungsmodell fuer Durchhangberechnungen. Durchhangberechnungen bei Hochtemperaturleitern

    Energy Technology Data Exchange (ETDEWEB)

    Scheel, Joerg; Dib, Ramzi [Fachhochschule Giessen-Friedberg, Friedberg (Germany); Sassmannshausen, Achim [DB Energie GmbH, Frankfurt (Main) (Germany). Arbeitsgebiet Bahnstromleitungen Energieerzeugungs- und Uebertragungssysteme; Riedl, Markus [Eon Netz GmbH, Bayreuth (Germany). Systemtechnik Leitungen

    2010-12-13

    Increasingly, high-temperature cables are used in high-voltage grids. Beyond a given temperature level, their slack span cannot be calculated accurately by conventional simple linear methods. The contribution investigates the behaviour of composite cables at high operating temperatures and its influence on the slack span and presents a more accurate, bilingual calculation method. (orig.)

  5. A two year randomized controlled trial of human caloric restriction: feasibility and effects on predictors of health span and longevity

    Science.gov (United States)

    Background: Caloric restriction (CR), energy intake reduced below ad libitum (AL) intake, increases life span in many species. The implications for humans can be clarified by randomized controlled trials of CR. Methods: To determine CRs feasibility, safety, and effects on predictors of longevity, di...

  6. Study of Semi-Span Model Testing Techniques

    Science.gov (United States)

    Gatlin, Gregory M.; McGhee, Robert J.

    1996-01-01

    An investigation has been conducted in the NASA Langley 14- by 22-Foot Subsonic Tunnel in order to further the development of semi-span testing capabilities. A twin engine, energy efficient transport (EET) model with a four-element wing in a takeoff configuration was used for this investigation. Initially a full span configuration was tested and force and moment data, wing and fuselage surface pressure data, and fuselage boundary layer measurements were obtained as a baseline data set. The semi-span configurations were then mounted on the wind tunnel floor, and the effects of fuselage standoff height and shape as well as the effects of the tunnel floor boundary layer height were investigated. The effectiveness of tangential blowing at the standoff/floor juncture as an active boundary-layer control technique was also studied. Results indicate that the semi-span configuration was more sensitive to variations in standoff height than to variations in floor boundary layer height. A standoff height equivalent to 30 percent of the fuselage radius resulted in better correlation with full span data than no standoff or the larger standoff configurations investigated. Undercut standoff leading edges or the use of tangential blowing in the standoff/ floor juncture improved correlation of semi-span data with full span data in the region of maximum lift coefficient.

  7. Developmental changes in the visual span for reading.

    Science.gov (United States)

    Kwon, Miyoung; Legge, Gordon E; Dubbels, Brock R

    2007-10-01

    The visual span for reading refers to the range of letters, formatted as in text, that can be recognized reliably without moving the eyes. It is likely that the size of the visual span is determined primarily by characteristics of early visual processing. It has been hypothesized that the size of the visual span imposes a fundamental limit on reading speed [Legge, G. E., Mansfield, J. S., & Chung, S. T. L. (2001). Psychophysics of reading. XX. Linking letter recognition to reading speed in central and peripheral vision. Vision Research, 41, 725-734]. The goal of the present study was to investigate developmental changes in the size of the visual span in school-age children and the potential impact of these changes on children's reading speed. The study design included groups of 10 children in 3rd, 5th, and 7th grade, and 10 adults. Visual span profiles were measured by asking participants to recognize letters in trigrams (random strings of three letters) flashed for 100ms at varying letter positions left and right of the fixation point. Two print sizes (0.25 degrees and 1.0 degrees ) were used. Over a block of trials, a profile was built up showing letter recognition accuracy (% correct) versus letter position. The area under this profile was defined to be the size of the visual span. Reading speed was measured in two ways: with Rapid Serial Visual Presentation (RSVP) and with short blocks of text (termed Flashcard presentation). Consistent with our prediction, we found that the size of the visual span increased linearly with grade level and it was significantly correlated with reading speed for both presentation methods. Regression analysis using the size of the visual span as a predictor indicated that 34-52% of variability in reading speeds can be accounted for by the size of the visual span. These findings are consistent with a significant role of early visual processing in the development of reading skills.

  8. Improving digit span assessment of short-term verbal memory.

    Science.gov (United States)

    Woods, David L; Kishiyamaa, Mark M; Lund, E William; Herron, Timothy J; Edwards, Ben; Poliva, Oren; Hink, Robert F; Reed, Bruce

    2011-01-01

    We measured digit span (DS) in two experiments that used computerized presentation of randomized auditory digits with performance-adapted list length adjustment. A new mean span (MS) metric of DS was developed that showed reduced variance, improved test-retest reliability, and higher correlations with the results of other neuropsychological test results when compared to traditional DS measures. The MS metric also enhanced the sensitivity of forward versus backward span comparisons, enabled the development of normative performance criteria with subdigit precision, and elucidated changes in DS performance with age and education level. Computerized stimulus delivery and improved scoring metrics significantly enhance the precision of DS assessments of short-term verbal memory.

  9. Research development of digital maintenance and management system for long-span cable-stayed bridges

    Institute of Scientific and Technical Information of China (English)

    REN Yuan; HUANG Qiao; SUN Yong-ming

    2009-01-01

    Digital cable-stayed bridge maintenance and management system (DCBMS) was developed for the need of maintenance and management of long-span cable-stayed bridges. In this paper, the major functions and theoretical application of eight modules were systematically stated with the background of Harbin Songhua River cable-stayed bridge, which include data management module, inspection and measurement module, assessment module, finite element analysis module, disease diagnosis and prediction module, maintenance module, query module and help module. By analyzing and calculating the data from manual inspection database, basic database and health monitoring subsystem, DCBMS can accomplish the functions like life prediction, disease diagnosis, comprehensive assessment, maintenance and management of bridges. Therefore, the maintenance and management of long-span cable-stayed bridges can be made digital, professional and scientific. By running this system, a real-time and specific technical guidance can be provided for the maintainers and managers of longspan cable-stayed bridges.

  10. Maintenance of cellular ATP level by caloric restriction correlates chronological survival of budding yeast

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Joon-Seok; Lee, Cheol-Koo, E-mail: cklee2005@korea.ac.kr

    2013-09-13

    Highlights: •CR decreases total ROS and mitochondrial superoxide during the chronological aging. •CR does not affect the levels of oxidative damage on protein and DNA. •CR contributes extension of chronological lifespan by maintenance of ATP level -- Abstract: The free radical theory of aging emphasizes cumulative oxidative damage in the genome and intracellular proteins due to reactive oxygen species (ROS), which is a major cause for aging. Caloric restriction (CR) has been known as a representative treatment that prevents aging; however, its mechanism of action remains elusive. Here, we show that CR extends the chronological lifespan (CLS) of budding yeast by maintaining cellular energy levels. CR reduced the generation of total ROS and mitochondrial superoxide; however, CR did not reduce the oxidative damage in proteins and DNA. Subsequently, calorie-restricted yeast had higher mitochondrial membrane potential (MMP), and it sustained consistent ATP levels during the process of chronological aging. Our results suggest that CR extends the survival of the chronologically aged cells by improving the efficiency of energy metabolism for the maintenance of the ATP level rather than reducing the global oxidative damage of proteins and DNA.

  11. The chronology of the India-Asia collision

    Science.gov (United States)

    Garzanti, Eduardo; Hu, Xiumian

    2016-04-01

    Markedly diverging interpretations and incompatible scenarios have been proposed for the early stages of the Himalayan Orogeny. One view is that the northern Indian passive margin may have been involved in ophiolite obduction, arc-continent, or continent-continent collision as early as the Late Cretaceous. A different view is that India may have not come into contact with Asia until as late as the Oligo-Miocene. Ages assigned to the India-Asia collision have thus ranged rather freely from as old as 70 Ma to as young as 25-20 Ma, allowing researchers to select in remarkable liberty the age that fitted best with their lines of reasoning. In recent years, however, a growing body of stratigraphic evidence has constrained the chronology of collision with increasing accuracy and precision. Provenance analysis has ruled out early collision or ophiolite-obduction hypotheses, indicating that renewed terrigenous supply in the Maastrichtian to Danian (72-62 Ma) was derived from India in the south - rejuvenated by magmatic upwelling during the Deccan event - rather than from Asia or from an obducting ophiolite in the north (Garzanti and Hu, 2015). Integrated biostratigraphy and detrital-zircon chronostratigraphy has demonstrated that the first continent-continent contact and consequent disappearance of Neotethyan oceanic lithosphere at one point in south Tibet took place in the Selandian (59 ± 1 Ma; DeCelles et al., 2014; Wu et al., 2014; Hu et al., 2015). A major disconformity documenting tectonic uplift of carbonate platforms all along the Tethys Himalaya from the Gamba and Tingri areas of south Tibet to the Zanskar Range of the NW Himalaya, allowed dating the arrival of the orogenic wave in the inner part of the northern Indian passive margin around the Paleocene/Eocene boundary (ca. 56 Ma; Garzanti et al., 1987; Li et al., 2015). Shallow-marine seaways linked with Neotethys persisted in the Himalaya until the mid-Ypresian (ca. 50 Ma), when they were finally filled by

  12. USING GENETIC ALGORTIHM TO SOLVE STEINER MINIMUM SPANNING TREE PROBLEM

    Directory of Open Access Journals (Sweden)

    Öznur İŞÇİ

    2006-03-01

    Full Text Available Genetic algorithms (GA are a stochastic research methods, and they produce solutions that are close to optimum or near optimum. In addition to GA's successful application to traveling salesman problem, square designation, allocation, workshop table, preparation of lesson/examination schedules, planning of communication networks, assembling line balanced, minimum spanning tree type many combinatorial optimization problems it would be applicable to make the best comparison in optimization. In this study a Java program is developed to solve Steiner minimum spanning tree problem by genetic algorithm and its performance is examined. According to the tests carried out on the problems that were given before in the literature, results that are close to optimum are obtained in by GA approach that is recommended in this study. For the predetermined points in the study, length and gain are calculated for Steiner minimum spanning tree problem and minimum spanning tree problem.

  13. Dutch life expectancy from an international perspective

    NARCIS (Netherlands)

    van Bodegom, D.; Bonneux, L.G.A.; Engelaer, F.M.; Lindenberg, J.; Meij, J.J.; Westendorp, R.G.J.

    2010-01-01

    In general, longer life spans go with longer lives with good quality. Abstention from smoking is an obvious target to get more out of our lives. The ability to better manage chronic diseases is a first step of progress. Life expectancy, disability and quality of life are distinct concepts and may ha

  14. Design and aerodynamic characteristics of a span morphing wing

    Science.gov (United States)

    Yu, Yuemin; Liu, Yanju; Leng, Jinsong

    2009-03-01

    Flight vehicles are often designed to function around a primary operating point such as an efficient cruise or a high maneuverability mode. Performance and efficiency deteriorate rapidly as the airplane moves towards other portions of the flight envelope. One solution to this quandary is to radically change the shape of the aircraft. This yields both improved efficiency and a larger flight envelope. This global shape change is an example of morphing aircraft . One concept of morphing is the span morphing wing in which the wingspan is varied to accommodate multiple flight regimes. This type of design allows for at least two discreet modes of the aircraft. The original configuration, in which the extensible portion of the wing is fully retracted, yields a high speed dash mode. Fully extending the wing provides the aircraft with a low speed mode tailored for fine tracking and loiter tasks. This paper discusses the design of a span morphing wing that permits a change in the aspect ratio while simultaneously supporting structural wing loads. The wing cross section is maintained by NACA 4412 rib sections . The span morphing wing was investigated in different configurations. The wing area and the aspect ratio of the span morphing wing increase as the wings pan increases. Computational aerodynamics are used to estimate the performance and dynamic characteristics of each wing shape of this span morphing wing as its wingspan is changed. Results show that in order to obtain the same lift, the conventional wing requires a larger angle of attach(AOA) than that of the span morphing wing.The lift of the span morphing wing increases as the wing span ,Mach number and AOA increases.

  15. SOLVING MINIMUM SPANNING TREE PROBLEM WITH DNA COMPUTING

    Institute of Scientific and Technical Information of China (English)

    Liu Xikui; Li Yan; Xu Jin

    2005-01-01

    Molecular programming is applied to minimum spanning problem whose solution requires encoding of real values in DNA strands. A new encoding scheme is proposed for real values that is biologically plausible and has a fixed code length. According to the characteristics of the problem, a DNA algorithm solving the minimum spanning tree problem is given. The effectiveness of the proposed method is verified by simulation. The advantages and disadvantages of this algorithm are discussed.

  16. Long span cable supported bridges - present technology and trends

    DEFF Research Database (Denmark)

    Gimsing, Niels Jørgen

    1998-01-01

    The activity within the field of long-span cable supported bridges has never been larger than at the end of the 20th century. The technology is well advanced to cope with the present challenges but it is also approaching its limits so if the trend towards ever increasing spans continues...... into the next century, further developments are required to ensure that the bridges will be stable, durable and constructible....

  17. Design of a variable-span morphing wing

    OpenAIRE

    Mestrinho, João Rafael da Conceição

    2009-01-01

    The present work focuses on the study, design and validation of a variable-span morphing wing to be tted to the UAV \\Olharapo". Using an optimization code, which uses a viscous two-dimensional panel method formulation coupled with a non-linear liftingline algorithm and a sequential quadratic programming optimization routine, na aerodynamic analysis is performed to estimate the optimal values of wing span which ensure minimum drag across the ight speed envelope. The UAV ies in a relativ...

  18. Progress in the Early Solar System Chronology: A Sketch of an Ever-Changing Landscape

    Science.gov (United States)

    Amelin, Yuri; Yin, Q.-Z.; Krot, A. N.; Bouvier, A.; Wadhwa, M.; Kleine, T.; Nyquist, L. E.

    2011-01-01

    The years since the Workshop on the Chronology of Meteorites and the Early Solar System, are marked with ongoing progress in cosmochronology. Rapid improvements in techniques, discovery of new meteorites unlike any previously known, and findings that what was deemed well established constants are actually variables, will be reflected in an updated review of the solar system chronology we are currently preparing. Along with updating the database of meteorite ages, it will involve development of a set of criteria for evaluation of accuracy and consistency of isotopic dates across the entire range of meteorite classes and isotope chronometer systems. Here we present some ideas on what we think is important in meteorite chronology, and invite the cosmochemistry community to discuss them.

  19. Evolution of Shanghai STOCK Market Based on Maximal Spanning Trees

    Science.gov (United States)

    Yang, Chunxia; Shen, Ying; Xia, Bingying

    2013-01-01

    In this paper, using a moving window to scan through every stock price time series over a period from 2 January 2001 to 11 March 2011 and mutual information to measure the statistical interdependence between stock prices, we construct a corresponding weighted network for 501 Shanghai stocks in every given window. Next, we extract its maximal spanning tree and understand the structure variation of Shanghai stock market by analyzing the average path length, the influence of the center node and the p-value for every maximal spanning tree. A further analysis of the structure properties of maximal spanning trees over different periods of Shanghai stock market is carried out. All the obtained results indicate that the periods around 8 August 2005, 17 October 2007 and 25 December 2008 are turning points of Shanghai stock market, at turning points, the topology structure of the maximal spanning tree changes obviously: the degree of separation between nodes increases; the structure becomes looser; the influence of the center node gets smaller, and the degree distribution of the maximal spanning tree is no longer a power-law distribution. Lastly, we give an analysis of the variations of the single-step and multi-step survival ratios for all maximal spanning trees and find that two stocks are closely bonded and hard to be broken in a short term, on the contrary, no pair of stocks remains closely bonded for a long time.

  20. Extinction chronology of the woolly rhinoceros Coelodonta antiquitatis in the context of late Quaternary megafaunal extinctions in northern Eurasia

    Science.gov (United States)

    Stuart, Anthony J.; Lister, Adrian M.

    2012-09-01

    Megafaunal extinctions in northern Eurasia (excluding Mediterranean islands) since the Last Interglacial claimed about 37% of species with body weights >44 kg. Here we review the dating evidence for the timings of these extinctions, which were staggered over tens of millennia. Moreover, individual species disappeared at different times in different geographical areas. For example, cave bear probably disappeared ca. 30.5-28.5 ka, at approximately the onset of GS-3 (beginning of 'LGM'), whereas cave lion survived until the Lateglacial ca 14 ka. Others survived into the Holocene: woolly mammoth until ca 10.7 ka in the New Siberian Islands and ca 4 ka on Wrangel Island, giant deer to at least 7.7 ka in western Siberia and European Russia. It is evident that climatic and vegetational changes had major impacts on species' ranges, and moreover the contrasting chronologies and geographical range contractions are consistent with environmental drivers relating to their differing ecologies. However, the possible role of humans in this process has still to be satisfactorily explored. We present a detailed review of the radiocarbon record and extinction chronology of an exclusively northern Eurasian species, the woolly rhinoceros Coelodonta antiquitatis, an animal adapted to feeding on low-growing herbaceous vegetation and a dry climate with minimal snowfall. During the Last Glacial the overall (time-averaged) range of C. antiquitatis extended across most of northern Eurasia, but the species failed to reach North America. On the basis of 233 ultrafiltered AMS radiocarbon dates, together with 50 others which pass our auditing criteria, we reconstruct a detailed chronology for this species. C. antiquitatis was widespread over most of the time span covered by radiocarbon dating, but from ca 35 ka (calibrated) it apparently contracted towards the east, culminating in its probable extinction ca 14 ka, with the latest dates from north-eastern Siberia. It disappeared from Britain, at

  1. 14C dates from Tel Rehov: Iron-Age chronology, pharaohs, and Hebrew kings.

    Science.gov (United States)

    Bruins, Hendrik J; van der Plicht, Johannes; Mazar, Amihai

    2003-04-11

    Stratified radiocarbon dates provide an independent chronological link between archaeological layers and historical data. The invasion by Pharaoh Shoshenq I (Shishak) is a key historical synchronism, approximately 925 B.C.E., mentioned in both Egyptian inscriptions and the Hebrew Bible. The list of places raided by Shoshenq, mentioned at Karnak (Egypt), includes Rehov (Israel). The site yielded a consistent series of radiocarbon dates from the 12th to 9th century B.C.E. Our results (i) suggest a revised Iron-Age chronology; (ii) date an archaeological stratum to Shoshenq's campaign; (iii) indicate the similarity of "Solomonic" and "Omride" pottery; and (iv) provide correlation with Greece and Cyprus.

  2. Tree-Ring Chronology of Pedunculate Oak (Quercus robur and its Potential for Development of Dendrochronological Research in Croatia

    Directory of Open Access Journals (Sweden)

    Katarina Čufar

    2014-06-01

    Full Text Available We present the local tree-ring chronology of pedunculate oak (Qercus robur from Kobiljak near Zagreb, Croatia (16º09’ E, 45º49’ N, 140 m a.s.l.. The chronology is based on 17 trees and is 127 years long and covers the period of 1883-2009. The well replicated part of the residual version of the ARSTAN chronology with SSS>0.80 (interval of 88 years, period 1922-2009 was used for dendroclimatological analysis, which showed that June precipitation has positive and temperature has negative effect on tree-ring variation. Comparison with 40 available oak chronologies from the surrounding countries confi rmed its good teleconnection with 2 local oak chronologies from Austria, 2 from Hungary, and 3 from Slovenia. It also exhibits good heteroconnection, i.e. similarity with chronologies of beech (Fagus sylvatica, from various sites in Slovenia. The similarities can be ascribed to response to common climatic factors. The results indicate that the chronology could be a good reference point for constructing a longer regional chronology in Croatia and surrounding countries, which could be used for different purposes including dating of objects of cultural heritage.

  3. Chronology of key belonging to different stages of the Scythian period in Tuva (Arzhan-1 and Arzhan-2 barrows)

    NARCIS (Netherlands)

    Zaitseva, G.I.; Chugunov, K.V.; Alekseev, A.Yu.; Dergachev, V.A.; Vasiliev, S.S.; Sementsov, A.A.; Cook, G.; Scott, E.M.; Plicht, J. van der; Parzinger, H.; Nagler, A.; Jungner, H.; Sonninen, E.; Bourova, N.D.

    2007-01-01

    This paper focuses on the chronological study of 2 Scythian period monuments that are the key to the chronology of the entire Eurasian Scythian culture. These are the unique monuments of Arzhan-1 and Arzhan-2 in Central Asia (Tuva Republic). The dating of both these monuments began immediately after

  4. The WAIS Divide deep ice core WD2014 chronology - Part 2: Annual-layer counting (0-31 ka BP)

    Science.gov (United States)

    Sigl, Michael; Fudge, Tyler J.; Winstrup, Mai; Cole-Dai, Jihong; Ferris, David; McConnell, Joseph R.; Taylor, Ken C.; Welten, Kees C.; Woodruff, Thomas E.; Adolphi, Florian; Bisiaux, Marion; Brook, Edward J.; Buizert, Christo; Caffee, Marc W.; Dunbar, Nelia W.; Edwards, Ross; Geng, Lei; Iverson, Nels; Koffman, Bess; Layman, Lawrence; Maselli, Olivia J.; McGwire, Kenneth; Muscheler, Raimund; Nishiizumi, Kunihiko; Pasteris, Daniel R.; Rhodes, Rachael H.; Sowers, Todd A.

    2016-03-01

    We present the WD2014 chronology for the upper part (0-2850 m; 31.2 ka BP) of the West Antarctic Ice Sheet (WAIS) Divide (WD) ice core. The chronology is based on counting of annual layers observed in the chemical, dust and electrical conductivity records. These layers are caused by seasonal changes in the source, transport, and deposition of aerosols. The measurements were interpreted manually and with the aid of two automated methods. We validated the chronology by comparing to two high-accuracy, absolutely dated chronologies. For the Holocene, the cosmogenic isotope records of 10Be from WAIS Divide and 14C for IntCal13 demonstrated that WD2014 was consistently accurate to better than 0.5 % of the age. For the glacial period, comparisons to the Hulu Cave chronology demonstrated that WD2014 had an accuracy of better than 1 % of the age at three abrupt climate change events between 27 and 31 ka. WD2014 has consistently younger ages than Greenland ice core chronologies during most of the Holocene. For the Younger Dryas-Preboreal transition (11.595 ka; 24 years younger) and the Bølling-Allerød Warming (14.621 ka; 7 years younger), WD2014 ages are within the combined uncertainties of the timescales. Given its high accuracy, WD2014 can become a reference chronology for the Southern Hemisphere, with synchronization to other chronologies feasible using high-quality proxies of volcanism, solar activity, atmospheric mineral dust, and atmospheric methane concentrations.

  5. Finite Span Effects on Flap Heating and Effectiveness in a Turbulent Boundary Layer.

    Science.gov (United States)

    1980-08-01

    Flap Span on Centerline Heating Distribution(15 Deflection) ........ ......................... 46 35 Span Edge Effect on Centerline Heat Transfer...Pressure Distributions at 87.5% Chord Station ....... ...................... 50 39 Span Edge Effect on Spanwise Pressure Distribution ........... 52 40...Distribution at 87.5% Chord Station ..... ............... 55 43 Span Edge Effect on Spanwise Heat Transfer Distribution ..... 56 44 Finite Span Effects

  6. Current issues in late Middle Palaeolithic chronology : New assessments from Northern Iberia

    NARCIS (Netherlands)

    Maroto, Julia; Vaquero, Manuel; Arrizabalaga, Alvaro; Baena, Javier; Baquedano, Enrique; Jorda, Jesus; Julia, Ramon; Montes, Ramon; Van Der Plicht, Johannes; Rasines, Pedro; Wood, Rachel

    2012-01-01

    The Iberian Peninsula plays a central role in the current debates on the Middle-Upper Palaeolithic transition and the Neanderthal extinction. This is largely due to the chronological data which some authors have suggested show a clear divide between Northern Iberia, where the Upper Palaeolithic appe

  7. A tree-ring and C-14 chronology of the key Sayan-Altai monuments

    NARCIS (Netherlands)

    Zaitseva, GI; Vasiliev, SS; Marsadolov, LS; Van der Plicht, J; Sementsov, AA; Dergachev, VA; Lebedeva, LM

    1998-01-01

    We present a radiocarbon chronology of key Sayan-Altai monuments from the Scythian period, based on a statistical analysis of dates produced in the 1980s and now supplemented with new dates. These new C-14 dates were produced for samples from the Tuekta-1 barrows (burial mounds) and were measured bo

  8. The absolute chronology and thermal processing of solids in the solar protoplanetary disk

    DEFF Research Database (Denmark)

    Connelly, James Norman; Bizzarro, Martin; Krot, Alexander N.;

    2012-01-01

    Transient heating events that formed calcium-aluminum - rich inclusions (CAIs) and chondrules are fundamental processes in the evolution of the solar protoplanetary disk, but their chronology is not understood. Using U-corrected Pb-Pb dating, we determined absolute ages of individual CAIs...

  9. Third-molar development in relation to chronologic age in young adults of central China.

    Science.gov (United States)

    Bai, Yuming; Mao, Jing; Zhu, Shengrong; Wei, Wei

    2008-08-01

    The estimation of chronologic age based on the stages of third-molar development was evaluated by using the eight stages (A-H) method of Demirjian and the third-molar development was compared, in terms of sex and age, with results of previous studies. The samples consisted of 291 orthopantomograms from young Chinese subjects of known chronologic age and sex (including 139 males with a mean age of 14.67+/-3.62 y and 152 females with a mean age of 14.85+/-3.70 y). Statistical analysis was performed by employing the Mann-Whitney U-test and the t-test. Regression analysis was conducted to obtain regression formulas for calculating dental age from the chronologic age. Our results showed statistically significant differences (Pthird-molar development between males and females, at the calcification stages D, E and H. And a strong correlation was found between age and third-molar development in both males (r (2)=0.65) and females (r (2)=0.61). New equations (Age=8.76+1.32 Development stage) for estimating chronologic age were derived. It is concluded that third-molar genesis took place earlier in males than in females. The use of third molars as a developmental marker is appropriate in young adults of Central China. The formula obtained in the present study can be used as a guide for estimation of dental maturity and a standard for age estimation for young adults of Central China.

  10. Chronological enumeration of nominal species and subspecies of Corydoras (Pisces, Siluriformes, Callichthyidae)

    NARCIS (Netherlands)

    Nijssen, H.; Isbrücker, I.J.H.

    1979-01-01

    A complete list of species and subspecies accepted as members of the genus Corydoras Lacépède, 1803, is given. They are arranged in chronological order. Invalid specific names are followed by their senior synonym. Nomina nuda are listed separately. A bibliography covering all publications containing

  11. The significance of peroxisome function in chronological aging of Saccharomyces cerevisiae

    NARCIS (Netherlands)

    Lefevre, Sophie D.; van Roermund, Carlo W.; Wanders, Ronald J. A.; Veenhuis, Marten; van der Klei, Ida J.

    2013-01-01

    Summary We studied the chronological lifespan of glucose-grown Saccharomyces cerevisiae in relation to the function of intact peroxisomes. We analyzed four different peroxisome-deficient (pex) phenotypes. These included Delta pex3 cells that lack peroxisomal membranes and in which all peroxisomal pr

  12. Legal Recognition of Same-Sex Couples in the Countries of the World : a Chronological Overview

    NARCIS (Netherlands)

    Waaldijk, C.; Marsh, V.

    2011-01-01

    Chronological overview of countries (and parts of countries) that have taken some major steps in legally recognising same-sex couples: legal recognition of non-registered same-sex cohabitation, introduction of a form of registered partnership, opening up of adoption and/or marriage for same-sex part

  13. Legal Recognition of Same-Sex Couples in the Countries of the World: a Chronological Overview

    OpenAIRE

    Waaldijk, C.; Marsh, V

    2011-01-01

    Chronological overview of countries (and parts of countries) that have taken some major steps in legally recognising same-sex couples: legal recognition of non-registered same-sex cohabitation, introduction of a form of registered partnership, opening up of adoption and/or marriage for same-sex partners.

  14. The effects of chronological age and size on toxicity of zinc to juvenile brown trout

    Science.gov (United States)

    A series of toxicity tests were conducted to investigate the role of chronological age and organism weight on zinc tolerance in juvenile brown trout (Salmo trutta). Four different incubation temperatures were used to control the maturation of the juveniles prior to zinc exposure...

  15. WD2014: A new reference chronology for ice cores from Antarctica?

    Science.gov (United States)

    Sigl, Michael; McConnell, Joseph R.; Winstrup, Mai; Fudge, Taylor J.; Cole-Dai, Jihong; Ferris, David; Taylor, Kendrick; Buizert, Christo; Rhodes, Rachael; McGwire, Ken; Welten, Kees C.; Woodruff, Thomas E.; Dunbar, Nelia; Iverson, Nels; Maselli, Olivia J.; Pasteris, Daniel R.; Muscheler, Raimund

    2015-04-01

    Here we present a chronology (WD2014) for the upper part (0-2850 m, 31.2 ka BP) of the West Antarctic Ice Sheet (WAIS)-Divide ice core which is based on layer counting of distinctive annual cycles preserved in the elemental, chemical and electrical conductivity records. These cycles are caused by the seasonally varying impurity concentrations in snowfall reflecting source strength of emissions, transport and deposition efficiency. A new ice core chronology has been developed using manual interpretation as well as by using a layer detection algorithm based on Hidden Markov Models taking advantage of the large suite of sub-annually resolved and co-registered aerosol records from high-resolution continuous measurements. The age model is validated against the absolute dated radiocarbon calibration curve IntCal13 using ice-core Be-10 measurements for proxy synchronization. These records reveal an unprecedented accuracy of the new ice core chronology since the Last Glacial Maximum. The new chronology can become a reference chronology for ice cores with synchronization to other ice cores achievable through the unique high-resolution sulfur record indicating hundreds of volcanic signals common to many other deep ice cores in Antarctica. A developing tephra framework for ice cores from West Antarctica will allow to better integrating Antarctic ice cores and the marine and terrestrial records from the southern hemisphere in the future, thus gaining a detailed chronologic picture of climatic changes and environmental consequences for the region over the past 31,000 years. This southern hemisphere perspective is a fundamental step in developing a detailed global understanding of the effects of past climate changes, and its implications for the future. Due to a small ice-age gas-age difference (delta-age) at WAIS Divide - because of high annual snowfall rates at this site - and a new high-resolution WAIS CH4 record, this new ice core chronology provides also independent

  16. Experimental Study on Free Spanning Submarine Pipeline Under Dynamic Excitation

    Institute of Scientific and Technical Information of China (English)

    李昕; 刘亚坤; 周晶; 马恒春; 朱彤

    2002-01-01

    Seismic load has a significant effect on the response of a free spanning submarine pipeline when the pipeline is constructed in a seismically active region. The model experiment is performed on an underwater shaking table to simulate the response of submarine pipelines under dynamic input. In consideration of the effects of the terrestrial and submarine pipeline, water depth, support condition, distance from seabed, empty and full pipeline, and span on dynamic response, 120 groups of experiments are conducted. Affecting factors are analyzed and conclnsions are drawn for reference. For the control of dynamic response, the span of a submarine pipeline is by far more important than the other factors. Meanwhile, the rosponse difference between a submarine pipeline under sine excitation and that under random excitation exists in experiments.

  17. Advanced aerostatic analysis of long-span suspension bridges

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    As the span length of suspension bridges increases, the diameter of cables and thus the wind load acting on them, the nonlinear wind-structure interaction and the wind speed spatial non-uniformity all increase consequently, which may have unnegligible influence on the aerostatic behavior of long-span suspension bridges. In this work, a method of advanced aerostatic analysis is presented firstly by considering the geometric nonlinearity, the nonlinear wind-structures and wind speed spatial non-uniformity. By taking the Runyang Bridge over the Yangtze River as example, effects of the nonlinear wind-structure interaction, wind speed spatial non-uniformity, and the cable's wind load on the aerostatic behavior of the bridge are investigated analytically. The results showed that these factors all have important influence on the aerostatic behavior, and should be considered in the aerostatic analysis of long and particularly super long-span suspension bridges.

  18. Assistant pullback technique for main span closure of Sutong Bridge

    Institute of Scientific and Technical Information of China (English)

    Chen Ming; Luo Chengbin; Wu Qihe; Zhang Yongtao; You Xinpeng

    2009-01-01

    Sutong Bridge is a cable-stayed steel box girder bridge with a main span of 1 088 m. The erection of upper structure adopts geometry control method and requires no change to the unit's size and the structure's none-stress geometry. Before main span closure, the cantilever of girder reaches 540.8 m, the structure state is noticeably influenced by external circumstances, the main span closure face great difficulty. By abstracting the advantage of the pullback method abroad and the domestic temperature-cutting method, a new assistant pullback method have put forward and bring into practice actually. In this paper, the analysis key point of practice conditions, key parameter of practice, main measures of the method and the performance is introduced.

  19. Approximate hydrodynamic design of a finite span hydrofoil

    Science.gov (United States)

    Vladimirov, A N

    1955-01-01

    Previous work on the motion of various bodies under the surface of a heavy fluid is discussed. The solution of the motion of a flat plate by Keldysh and Lavrentiev is applied to the motion of a hydrofoil, making possible the presentation of charts for determining the lift and resistance of an infinite span hydrofoil operating in a heavy frictionless fluid having infinite depth below the free water surface. Consideration is given to the effects of viscosity and a method is suggested to correct for the finite span. The effect of the water surface on the downwash behind the foil is also discussed. A comparison of theoretical results obtained from this work with experimental data indicates that a basis for the approximate hydrodynamic design of a finite span hydrofoil has been achieved.

  20. POSTMENOPAUSAL BLEEDING: HISTOPATHOLOGICAL SPECTRUM AND ASSOCIATION WITH AGE AND CLEAR SPAN: CASE SERIES OF 328 CASES

    Directory of Open Access Journals (Sweden)

    Ruchita

    2014-06-01

    Full Text Available : Introduction: Postmenopausal bleeding is defined as vaginal bleeding occurring after twelve months of amenorrhea in a woman of the age where the menopause can be expected. With increase in life expectancy, a larger proportion of female population will be in postmenopausal age group; hence, the incidence of postmenopausal bleeding is expected to increase. AIM: We studied the prevalence of malignancy as well as the histopathological spectrum of genital tract lesions in cases of postmenopausal bleeding. The association between age, period between cessation of menses and onset of bleeding per vaginum (clear span was also studied. RESULTS: Malignant causes were more common (58.5% than benign causes and included cervical carcinoma, malignant uterine tumors (13.1%, carcinoma vagina (4.3%, malignant ovarian tumors (5.5%, carcinoma vulva (0.9% and carcinoma fallopian tube (0.3%. Squamous cell carcinoma was the commonest among cervical malignancies. The benign causes included polyps (16.5%, endometrial hyperplasia (4.9%, adenomyosis (2.7%, atrophic endometrium (2.4%, cervicitis (2.1%, leiomyoma (1.8%, proliferative endometrium (1.5%, endometritis (1.5%, secretory endometrium (1.2%, retained IUCD (0.9% and uterovaginal prolapse (0.6%. The likelihood of malignancy increased significantly with advancing age (p-value 0.042. The clear span of cases with malignant tumors was significantly longer than the clear span of cases with benign lesions. Hence, the likelihood of malignancy increased with length of clear span (p-value 0.00809. CONCLUSION: Any postmenopausal patient with vaginal bleeding needs to be investigated thoroughly to determine the cause of the bleeding and should be considered to have abnormal histopathology until proved otherwise

  1. Age determination of marine sediments in the western North Pacific by aspartic acid chronology

    Energy Technology Data Exchange (ETDEWEB)

    Harada, Naomi; Kusakabe, Masashi [Japan Marine Science and Technology Center, Yokosuka, Kanagawa (Japan); Handa, Nobuhiko; Oba, Tadamichi; Matsuoka, Hiromi; Kimoto, Katsunori

    1997-02-01

    The ages of fossil planktonic foraminifera, Pulleniatina obliquiloculata, in sediments (core 3bPC) from the western North Pacific were determined by aspartic acid chronology, which uses the racemization reaction rate constant of aspartic acid (k{sub Asp}). Aspartic acid racemization-based ages (Asp ages) ranged from 7,600 yrBP at the surface, to 307,000 yrBP at a depth of 352.9 cm in the sediments. This sediment core was also dated by the glacial-interglacial fluctuation of {sigma}{sup 18}O chronology, and the ages determined by both chronologies were compared. The ages derived from aspartic acid chronology and {sigma}{sup 18}O stratigraphy were more or less consistent, but there appeared to be some differences in age estimates between these two dating methods at some depths within the core. In the core top sediments, the likely cause for the age discrepancy could be the loss of the surface sediment during sampling of the core. At depths of 66.3 and 139 cm within the core, Asp ages indicated reduced sedimentation rates during ca. 60,000-80,000 yrBP and ca. 140,000-190,000 yrBP. The maximum age differences in both chronologies are 33,000 yr and 46,600 yr during each of these periods. These anomalous reductions in sedimentation rates occurring during these periods could possibly be related to some geological events, such as an increased dissolution effect of the calcium carbonate in the western North Pacific. Another possible reason for these age differences could be the unreliability in {sigma}{sup 18}O ages of core 3bPC as they were estimated by {sigma}{sup 18}O ages of another core, 3aPC. (author)

  2. A first chronology for the North Greenland Eemian Ice Drilling (NEEM) ice core

    Science.gov (United States)

    Rasmussen, S. O.; Abbott, P. M.; Blunier, T.; Bourne, A. J.; Brook, E.; Buchardt, S. L.; Buizert, C.; Chappellaz, J.; Clausen, H. B.; Cook, E.; Dahl-Jensen, D.; Davies, S. M.; Guillevic, M.; Kipfstuhl, S.; Laepple, T.; Seierstad, I. K.; Severinghaus, J. P.; Steffensen, J. P.; Stowasser, C.; Svensson, A.; Vallelonga, P.; Vinther, B. M.; Wilhelms, F.; Winstrup, M.

    2013-12-01

    A stratigraphy-based chronology for the North Greenland Eemian Ice Drilling (NEEM) ice core has been derived by transferring the annual layer counted Greenland Ice Core Chronology 2005 (GICC05) and its model extension (GICC05modelext) from the NGRIP core to the NEEM core using 787 match points of mainly volcanic origin identified in the electrical conductivity measurement (ECM) and dielectrical profiling (DEP) records. Tephra horizons found in both the NEEM and NGRIP ice cores are used to test the matching based on ECM and DEP and provide five additional horizons used for the timescale transfer. A thinning function reflecting the accumulated strain along the core has been determined using a Dansgaard-Johnsen flow model and an isotope-dependent accumulation rate parameterization. Flow parameters are determined from Monte Carlo analysis constrained by the observed depth-age horizons. In order to construct a chronology for the gas phase, the ice age-gas age difference (Δage) has been reconstructed using a coupled firn densification-heat diffusion model. Temperature and accumulation inputs to the Δage model, initially derived from the water isotope proxies, have been adjusted to optimize the fit to timing constraints from δ15N of nitrogen and high-resolution methane data during the abrupt onset of Greenland interstadials. The ice and gas chronologies and the corresponding thinning function represent the first chronology for the NEEM core, named GICC05modelext-NEEM-1. Based on both the flow and firn modelling results, the accumulation history for the NEEM site has been reconstructed. Together, the timescale and accumulation reconstruction provide the necessary basis for further analysis of the records from NEEM.

  3. Quantitative and qualitative approaches to identifying migration chronology in a continental migrant

    Science.gov (United States)

    Beatty, William S.; Kesler, Dylan C.; Webb, Elisabeth B.; Raedeke, Andrew H.; Naylor, Luke W.; Humburg, Dale D.

    2013-01-01

    The degree to which extrinsic factors influence migration chronology in North American waterfowl has not been quantified, particularly for dabbling ducks. Previous studies have examined waterfowl migration using various methods, however, quantitative approaches to define avian migration chronology over broad spatio-temporal scales are limited, and the implications for using different approaches have not been assessed. We used movement data from 19 female adult mallards (Anas platyrhynchos) equipped with solar-powered global positioning system satellite transmitters to evaluate two individual level approaches for quantifying migration chronology. The first approach defined migration based on individual movements among geopolitical boundaries (state, provincial, international), whereas the second method modeled net displacement as a function of time using nonlinear models. Differences in migration chronologies identified by each of the approaches were examined with analysis of variance. The geopolitical method identified mean autumn migration midpoints at 15 November 2010 and 13 November 2011, whereas the net displacement method identified midpoints at 15 November 2010 and 14 November 2011. The mean midpoints for spring migration were 3 April 2011 and 20 March 2012 using the geopolitical method and 31 March 2011 and 22 March 2012 using the net displacement method. The duration, initiation date, midpoint, and termination date for both autumn and spring migration did not differ between the two individual level approaches. Although we did not detect differences in migration parameters between the different approaches, the net displacement metric offers broad potential to address questions in movement ecology for migrating species. Ultimately, an objective definition of migration chronology will allow researchers to obtain a comprehensive understanding of the extrinsic factors that drive migration at the individual and population levels. As a result, targeted

  4. Quantitative and qualitative approaches to identifying migration chronology in a continental migrant.

    Science.gov (United States)

    Beatty, William S; Kesler, Dylan C; Webb, Elisabeth B; Raedeke, Andrew H; Naylor, Luke W; Humburg, Dale D

    2013-01-01

    The degree to which extrinsic factors influence migration chronology in North American waterfowl has not been quantified, particularly for dabbling ducks. Previous studies have examined waterfowl migration using various methods, however, quantitative approaches to define avian migration chronology over broad spatio-temporal scales are limited, and the implications for using different approaches have not been assessed. We used movement data from 19 female adult mallards (Anas platyrhynchos) equipped with solar-powered global positioning system satellite transmitters to evaluate two individual level approaches for quantifying migration chronology. The first approach defined migration based on individual movements among geopolitical boundaries (state, provincial, international), whereas the second method modeled net displacement as a function of time using nonlinear models. Differences in migration chronologies identified by each of the approaches were examined with analysis of variance. The geopolitical method identified mean autumn migration midpoints at 15 November 2010 and 13 November 2011, whereas the net displacement method identified midpoints at 15 November 2010 and 14 November 2011. The mean midpoints for spring migration were 3 April 2011 and 20 March 2012 using the geopolitical method and 31 March 2011 and 22 March 2012 using the net displacement method. The duration, initiation date, midpoint, and termination date for both autumn and spring migration did not differ between the two individual level approaches. Although we did not detect differences in migration parameters between the different approaches, the net displacement metric offers broad potential to address questions in movement ecology for migrating species. Ultimately, an objective definition of migration chronology will allow researchers to obtain a comprehensive understanding of the extrinsic factors that drive migration at the individual and population levels. As a result, targeted

  5. Quantitative and qualitative approaches to identifying migration chronology in a continental migrant.

    Directory of Open Access Journals (Sweden)

    William S Beatty

    Full Text Available The degree to which extrinsic factors influence migration chronology in North American waterfowl has not been quantified, particularly for dabbling ducks. Previous studies have examined waterfowl migration using various methods, however, quantitative approaches to define avian migration chronology over broad spatio-temporal scales are limited, and the implications for using different approaches have not been assessed. We used movement data from 19 female adult mallards (Anas platyrhynchos equipped with solar-powered global positioning system satellite transmitters to evaluate two individual level approaches for quantifying migration chronology. The first approach defined migration based on individual movements among geopolitical boundaries (state, provincial, international, whereas the second method modeled net displacement as a function of time using nonlinear models. Differences in migration chronologies identified by each of the approaches were examined with analysis of variance. The geopolitical method identified mean autumn migration midpoints at 15 November 2010 and 13 November 2011, whereas the net displacement method identified midpoints at 15 November 2010 and 14 November 2011. The mean midpoints for spring migration were 3 April 2011 and 20 March 2012 using the geopolitical method and 31 March 2011 and 22 March 2012 using the net displacement method. The duration, initiation date, midpoint, and termination date for both autumn and spring migration did not differ between the two individual level approaches. Although we did not detect differences in migration parameters between the different approaches, the net displacement metric offers broad potential to address questions in movement ecology for migrating species. Ultimately, an objective definition of migration chronology will allow researchers to obtain a comprehensive understanding of the extrinsic factors that drive migration at the individual and population levels. As a result

  6. The Number of Spanning Trees in the Composition Graphs

    Directory of Open Access Journals (Sweden)

    Feng Li

    2014-01-01

    Full Text Available Using the composition of some existing smaller graphs to construct some large graphs, the number of spanning trees and the Laplacian eigenvalues of such large graphs are also closely related to those of the corresponding smaller ones. By using tools from linear algebra and matrix theory, we establish closed formulae for the number of spanning trees of the composition of two graphs with one of them being an arbitrary complete 3-partite graph and the other being an arbitrary graph. Our results extend some of the previous work, which depend on the structural parameters such as the number of vertices and eigenvalues of the small graphs only.

  7. Fiber span failure protection in mesh optical networks

    Science.gov (United States)

    Li, Guangzhi; Doverspike, Robert; Kalmanek, Charles

    2001-08-01

    A major challenge of optical network design is deciding where spare capacity is needed and how much, so that interrupted traffic may be rerouted in the event of a failure. Given the optical network topology and traffic forecast, the network design needs to map the traffic forecast into optical connection demands. For each optical connection demand, two paths need to be computed, i.e., a service path and a restoration path. In most cases, optical network design mainly considers single failure. If two service paths do not share any single failure, their restoration paths can share the same capacity on any links that they have in common. In this way, the total spare capacity needed for restoration can be dramatically reduced. However, due to the layered architecture in optical networks, a pair of diverse paths in a particular layer won't necessarily be diverse when the lower layer topology is considered. For example, optical networks are typically built on top of a network of fiber spans. A single span cut in the fiber network can cause multiple link failures in the optical layer. In this paper, we investigate fiber span failure protection scenarios in mesh optical networks. Specifically, we provide an algorithm to find two fiber span disjoint paths for each demand, such that the total spare capacity allocated in the network is minimized. Another problem that arises in restoration path computation is the existence of a trap topology. In a trap topology, the pre- selected service path may not have a diverse restoration path even though two diverse paths exist in the network. For simple link-disjoint protection, the min-cost max-flow algorithm can be used to avoid this problem. For fiber span failure protection, the trap topology problem becomes complicated. We show that it is NP-hard problem to find the maximum number of fiber-span disjoint paths between two nodes. We provide two heuristic algorithms to solve this trap topology problem. We have implemented fiber span

  8. Planetary Environments and Origins of Life

    Directory of Open Access Journals (Sweden)

    Ollivier Marc

    2014-02-01

    Full Text Available The present strategies proposed for the search for the origins of life and for extra-terrestrial life are mainly based on Earth-life and its adaptation along geological eras to the Earth environment. These strategies should however face the difficulty that one cannot as yet accurately date the appearance of life on Earth, and consequently one cannot identify a chronology of phenomena related to the transition from the non-living to the living and the dependence of these phenomena on the Earth environment. In this paper, we present new approaches to search for the origins of life on the Earth and next, for life on exoplanets. This study is based on our experience gained at the head of the CNRSc interdisciplinary research initiative "Environnements Planétaires et Origines de la Vie (EPOVd, and on the analysis of the projects the initiative funded.

  9. Palladium-silver chronology of IAB iron meteorites

    Science.gov (United States)

    Theis, K. J.; Schönbächler, M.; Benedix, G. K.; Rehkämper, M.; Andreasen, R.; Davies, C.

    2013-01-01

    The extinct 107Pd-107Ag decay system (half-life ˜6.5 Ma) is a useful chronometer to constrain the thermal evolution of the IAB parent body. To this end, Pd/Ag concentrations and the Ag isotope compositions of metals separated from 6 different IAB iron meteorites were determined. The samples show ɛ107Ag variations between +0.1 and +15.8 with 108Pd/109Ag ratios between 38 and 200. The data can be divided into two groups based on their petrology, each defining an isochron: a graphite and troilite rich inclusion bearing group (A), with the IAB meteorites Toluca, Odessa and Canyon Diablo and a more silicate rich group (B), which includes Campo Del Cielo, Caddo County and Goose Lake. Using the initial abundance of 107Pd derived from carbonaceous chondrites, the corresponding age for the group (A) is 18.7 (+3.6/-5.0) Ma after the start of the solar system and 14.9 (+2.5/-4.9) Ma for the group (B). This suggests that the last thermal event to reach high enough temperatures to melt metal on the IAB parent body occurred within the first 15 Ma of our solar system.

  10. (UnResolved contradictions in the Late Pleistocene glacial chronology of the Southern Carpathians - new samples and recalculated cosmogenic radionuclide age estimates

    Directory of Open Access Journals (Sweden)

    Zsófia RUSZKICZAY-RÜDIGER

    2014-11-01

    recent constants for the exposure age calculations has not been considered in the most recent review on the timing of the LGM (Hughes et al., 2013.Main objective of our study is to utilize the potential offered by the cosmogenic in situ produced 10Be dating to disentangle the contradictions in the available Southern Carpathian Late Pleistocene glacial chronology (Kuhlemann et al, 2013a; Reuther et al, 2004, 2007. We recalculate 10Be data published by Reuther et al. (2007 in accordance with the new half-life and production rate of 10Be. Besides, a new sample set has been collected to establish a precise chronological framework supported by in-situ exposure dating of several additional moraine generations.

  11. Numerical simulation of flows around long-span flat roof

    Institute of Scientific and Technical Information of China (English)

    SUN Xiao-ying; WU Yue; SHEN Shi-zhao

    2005-01-01

    Long-span roof with span larger than height always has a complicated three-dimensional curve. Wind pressure on the roof is often influenced not only by the atmospheric turbulence, but also by the "signature" turbulence provoked in the wind by the structure itself. So it is necessary to study characteristics of flows around the roof. In this paper, three-dimensional numerical simulation of wind-induced pressure has been performed on a long-span flat roof by means of Computational Fluid Dynamics (CFD) software--FLUENT. The flow characteristics are studied by considering some parameters, such as wind direction, span-height ratio, roof pitch, flow characteristics, roughness of terrain. The simulation is based upon the Reynolds-averaged equations, in which Reynolds stress equation model (RSM) and SIMPLE technology (Semi-Implicit Method for Pressure-Linked Equations) have been used. Compared with wind tunnel tests, the computational results have good agreement with the experimental data. It is proved that the results are creditable and the method is feasible.

  12. Definition of Measure-theoretic Pressure Using Spanning Sets

    Institute of Scientific and Technical Information of China (English)

    Lian Fa HE; Jin Feng LV; Li Na ZHOU

    2004-01-01

    We introduce a new definition of measure-theoretic pressure for ergodic measures of continuous maps on a compact metric space. This definition is similar to those of topological pressure involving spanning sets. As an application, for C1+α(α> 0) diffeomorphisms of a compact manifold, we study the relationship between the measure-theoretic pressure and the periodic points.

  13. On the way toward the sector spanning agrifood process traceability

    Directory of Open Access Journals (Sweden)

    Mónika Varga

    2010-05-01

    Full Text Available Having overviewed the state-of-art in agrifood traceability, the paper focuses on the multiscale modeling of the underlying problems. The main conclusion is, that there are not really workable sector spanning traceability methods, but the field experts and the computer modeling community seems to be prepared to develop quite new tools in the near future. According to our opinion, the sector encompassing IT centers ought to find a reasonable compromise between the “Schylla” of the simple, step by step passing of traceable unit IDs for the neighboring actors, and the “Carybdis” of accumulating enormously huge databases, containing every relevant data of the actors. The future role of the sector spanning, outside intelligent centers is to provide traceability and trackability service for the actors on cooperative basis of the mutual interests. In addition, the centers have to support the supply chain and value chain management, as well as the work of the authorities, that are responsible for the human health. Present study provides a good basis to our future development of a really sector spanning method. In a following paper we shall outline a sector spanning system on the basis of the Direct Computer Mapping based simulation methodology, in detail.

  14. A Table Based Algorithm for Minimum Directed Spanning Trees

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    As far as the weighted digraph is considered, an optimal directed spanning tree algorithm called table basedalgorithm (TBA) ia proposed in the paper based on the table instead of the weighted digraph. The optimality is proved,and a numerical example is demonatrated.

  15. Seismic Performance of Multi-Span RC Railway Bridges

    DEFF Research Database (Denmark)

    Georgakis, Christos; Barrau, Xavier

    2008-01-01

    Presently, there is no clear method for determining the optimal railway bridge design for a particular ground type and expected seismic intensity. Four main types of RC bridge dominate the current multi-span railway bridge design trends – the Simply Supported Beam, Continuous Box-Girder (CBG), CBG...

  16. 1-Skeletons of the Spanning Tree Problems with Additional Constraints

    Directory of Open Access Journals (Sweden)

    V. A. Bondarenko

    2015-01-01

    Full Text Available In this paper, we study polyhedral properties of two spanning tree problems with additional constraints. In the first problem, it is required to find a tree with a minimum sum of edge weights among all spanning trees with the number of leaves less than or equal to a given value. In the second problem, an additional constraint is the assumption that the degree of all nodes of the spanning tree does not exceed a given value. The recognition versions of both problems are NP-complete. We consider polytopes of these problems and their 1-skeletons. We prove that in both cases it is a NP-complete problem to determine whether the vertices of 1-skeleton are adjacent. Although it is possible to obtain a superpolynomial lower bounds on the clique numbers of these graphs. These values characterize the time complexity in a broad class of algorithms based on linear comparisons. The results indicate a fundamental difference between combinatorial and geometric properties of the considered problems from the classical minimum spanning tree problem.

  17. On the number of spanning trees in random regular graphs

    DEFF Research Database (Denmark)

    Greenhill, Catherine; Kwan, Matthew; Wind, David Kofoed

    2014-01-01

    Let d >= 3 be a fixed integer. We give an asympotic formula for the expected number of spanning trees in a uniformly random d-regular graph with n vertices. (The asymptotics are as n -> infinity, restricted to even n if d is odd.) We also obtain the asymptotic distribution of the number of spanni...

  18. The Chronology of Asteroid Accretion, Differentiation, and Secondary Mineralization

    Science.gov (United States)

    Nyquist, L. E.; Kleine, T.; Shih, C.-Y.; Reese, Y. D.

    2008-01-01

    We evaluate initial (Al-26/Al-27)(sub I), (Mn-53/Mn-55)(sub I), (Hf-182/Hf-180)(sub I), and Pb-207/Pb-206 ages for igneous differentiated meteorites and chondrules from ordinary chondrites for consistency with radioactive decay of the parent nuclides within a common, closed isotopic system, i.e., the early solar nebula. We find that the relative abundances of Al-26, Mn-53, and Hf-182, here denoted by I(Al)(sub CAI, I(Mn)(sub CAI) and I(Hf)(sub CAI), are consistent with decay from common initial values for the bulk solar system. I(Mn)(sub CAI) and I(Hf)(sub CAI) = 9.1+/-1.7 x 10(exp -6) and 1.06+/-0.09 x 10(exp -6) respectively, correspond to the canonical value of I(Al)(sub CAI) = 5.1 x 10(exp -5). I(Hf)(sub CAI) thus determined is consistent with I(Hf)(sub CAI) = 1.003+/-0.045 x 10(exp -6) directly determined in separate work. I(Mn)(sub CAI) is within error of the lowest value directly determined for CAI. We suggest that erratically higher values directly determined for CAI in carbonaceous chondrites reflect proton irradiation of unaccreted CAIs by the early Sun after other asteroids destined for melting by Al-26 decay had already accreted. The Mn-53 incorporated within such asteroids would have been shielded from further "local" spallogenic contributions. The relative abundances of the short-lived nuclides are less consistent with the Pb-207/Pb-206 ages of the corresponding materials with the best consistency being obtained between (Hf-182/Hf-180)(sub I) and Pb-207/Pb-206 ages of angrites. (Hf-182/Hf-180)(sub I) decreases with decreasing Pb-207/Pb-206 ages at the rate expected from the 8.90+/-0.09 Ma half-life of Hf-182. However, the model "CAI age" thus determined, T(sub CAI,Mn-W) = 4568.6+/-0.7 Ma, is older than the commonly accepted directly measured value T(sub CAI) = 4567.l+/-0.2 Ma. I(Al)(sub I), and (Mn-53/Mn-55)(sub I) are less consistent with Pb-207/Pb-206 ages, but determine T(sub CAI, Mn-Cr) = 4568.3+/-0.5 Ma relative to I(AI)(sub CAI)= 5.1 x 10(exp -5

  19. Searching for a Life-Span Psychobiology of Down Syndrome: Advancing Educational and Behavioural Management Strategies.

    Science.gov (United States)

    Gibson, David

    1991-01-01

    Recent experimental research is synthesized to identify distinctive biobehavioral characteristics of Down's Syndrome persons across their lifespan. It is argued that educational and other intervention programs have not demonstrated strong gains having significant durability or generalization. Recommended is an interactionist function-structure…

  20. Delusional Disorder over the Reproductive Life Span: The Potential Influence of Menopause on the Clinical Course

    Directory of Open Access Journals (Sweden)

    Alexandre González-Rodríguez

    2015-01-01

    Full Text Available Background and Objectives. Recent evidence supports an association between estrogen levels and severity of psychopathology in schizophrenia women. Our main goal was to investigate whether delusional disorder (DD women with premenopausal onset and those with postmenopausal onset differ in demographic and clinical features. Methods. Psychopathological symptoms were assessed in 80 DD women (DSM-IV-TR, at baseline and after six and 24 months. Scores in the PANSS, PSP for functionality, HRSD 17 items, C-SSRS for suicide, and the SUMD were considered outcome variables. For comparison purposes, t- and χ2-tests were performed and nonparametric tests when necessary. Analysis of Covariance (ANCOVA was conducted for multivariate comparisons. Results. 57 out of 80 DD women completed the study. When unadjusted, DD with premenopausal onset had a longer DUP, higher educational level, and a tendency toward higher rates of gynaecological disorders. Erotomanic type was most frequent in DD women premenopausal onset, and somatic and jealous types were most frequent in those with postmenopausal onset. After 24 months, DD women with premenopausal onset showed higher depressive symptoms and a tendency toward higher rates of psychotic relapses. Conclusions. Our results support that some aspects of psychopathology and insight may differ according to the onset of DD and the reproductive status.

  1. Metabolic rate affects adult life span independently of developmental rate in parasitoid wasps

    NARCIS (Netherlands)

    Seyahooei, M.A.; van Alphen, J.J.M.; Kraaijeveld, K.

    2011-01-01

    Developmental time and body size correlate with lifespan in a wide range of taxa, although not in insect parasitoids. When the rate of development is independent of adult metabolic rate, adult lifespan is free to adapt to the adult environment. We suggest that interspecific variation in intrinsic ad

  2. Socio-Demographic Predictors of Loneliness Across the Adult Life Span in Portugal

    OpenAIRE

    Félix Neto

    2014-01-01

    Loneliness, a complex phenomenon, is experienced differently by people under diverse conditions. The factors influencing loneliness are numerous and may vary between cultures. The purpose of this study was to show socio-demographic factors contributing to loneliness in Portugal. The sample consisted of 3,144 participants with a mean age of 46.90 (SD = 22.56) and a range between 15 and 92 years. Loneliness was evaluated with the Revised UCLA Loneliness Scale (Russell, Peplau, & Cutrona, 1980)....

  3. Socio-Demographic Predictors of Loneliness Across the Adult Life Span in Portugal

    Directory of Open Access Journals (Sweden)

    Félix Neto

    2014-12-01

    Full Text Available Loneliness, a complex phenomenon, is experienced differently by people under diverse conditions. The factors influencing loneliness are numerous and may vary between cultures. The purpose of this study was to show socio-demographic factors contributing to loneliness in Portugal. The sample consisted of 3,144 participants with a mean age of 46.90 (SD = 22.56 and a range between 15 and 92 years. Loneliness was evaluated with the Revised UCLA Loneliness Scale (Russell, Peplau, & Cutrona, 1980. Age and marital status were significant predictors of loneliness. Loneliness increased with age, and divorced or windowed participants reported higher loneliness than single or married people. As expected, gender did not significantly contribute to loneliness. This work identified vulnerable people who are experiencing a perceived dissatisfaction with their social interactions that needs special attention. These vulnerable groups include the old, divorced and widowed. In particular, policy makers and other experts who work with old persons should promote interventions according to their needs.

  4. Differential Effects of Emotional Information on Interference Task Performance across the Life Span

    Directory of Open Access Journals (Sweden)

    Haley M LaMonica

    2010-09-01

    Full Text Available While functioning in multiple domains declines with age, emotional regulation appears to remain preserved in older adults. The Emotion Inhibition (Emotional Stroop Test requires participants to name the ink color in which neutrally- and emotionally-valenced words are printed. It was employed in the current investigation as a measure of affective regulation in the context of an interference task in relation to age. Results demonstrated that while participants ranging from 20 to 50 years of age performed significantly worse on the emotion Stroop Inhibition relative to the neutral Stroop Inhibition condition, subjects over 60 years of age displayed the converse of this pattern, performing better on the emotion than the neutral condition, suggesting that they are less affected by the emotional impact of the positive and negative words used in the former condition. This pattern of age-related change in the ability to manage emotion may be related to blunting of affective signaling in limbic structures or, at the psychological level, focusing on emotional regulation.

  5. Curcumin Stimulates Biochemical Mechanisms of Apis Mellifera Resistance and Extends the Apian Life-Span

    Directory of Open Access Journals (Sweden)

    Strachecka Aneta J.

    2015-06-01

    Full Text Available We examined the influence of curcumin-supplemented feeding on worker lifespan, Nosema resistance, key enzyme activities, metabolic compound concentrations and percentage of the global DNA methylation. Two worker groups (Apis mellifera were set up: 1 control group; workers were fed ad libitum with sucrose syrup; 2 workers were fed with the syrup with the addition of curcumin. Dead workers were removed every two days and the Nosema spp. infection levels were assessed. Hemolymph was taken from living workers for biochemical analyses. The global DNA methylation level was analysed using DNA from worker heads and thoraces. The bees that consumed curcumin lived longer and were less infested with Nosema spp. The curcumin-treated workers had higher concentrations of proteins, non-enzymatic biomarkers (triglycerides, glucose, cholesterol, Mg2+ and Ca2+, uric acid and creatinine, as well as elevated activities of antioxidant enzymes (SOD , GPx, CAT , GST , neutral proteases, protease inhibitors, enzymatic biomarkers (AST , ALT , ALP . The concentrations of albumin and urea, and the activities of acidic and alkaline proteases were higher in the control group. Curcumin decreased global DNA methylation levels especially in older bees in which the natural, age-related level increase was observed. Most of the parameters increased over the apian youth and adulthood, and decreased in older bees. The decrease was markedly delayed in the bees fed with curcumin. Curcumin appeared to be an unexpectedly effective natural bio-stimulator, improving apian health and vitality. This multifactorial effect is caused by the activation of many biochemical processes involved in the formation of apian resistance.

  6. Structural and functional brain changes related to different types of physical activity across the life span.

    Science.gov (United States)

    Voelcker-Rehage, Claudia; Niemann, Claudia

    2013-11-01

    Physical activity has been shown to improve cognitive functioning. Research has largely focused on cognitive facilitation by cardiovascular exercise in older adults. Only few studies have investigated younger age groups or other types of physical activity. In this paper we review and summarize common results found in recent studies of metabolic (i.e. cardiovascular and resistance) and coordinative exercise. Findings from human motor learning are utilized to complement results on coordinative exercise. Results show that both types of exercise affect the brain differently. We propose possible mechanisms by which physical activity facilitates cognitive performance by briefly reviewing microscopic structural changes in animal research. Lastly, we highlight open research questions.

  7. Avoiding threat in late adulthood: testing two life span theories of emotion.

    Science.gov (United States)

    Orgeta, Vasiliki

    2011-07-01

    The purpose of the present research was to explore the time course of age-related attentional biases and the role of emotion regulation as a potential mediator of older adults' performance in an emotion dot probe task. In two studies, younger and older adults (N = 80) completed a visual probe detection task, which presented happy, angry, and sad facial expressions. Across both studies, age influenced attentional responses to angry faces. Results indicated a bias away from angry-related facial emotion information occurring relatively late in attention. Age effects were not attributable to decreasing information processing speed or visuoperceptual function. Current results demonstrated that an age-related attentional preference away from angry facial cues was mediated by efforts to suppress emotion. Findings are discussed in relation to current theories of sociocognitive aging.

  8. Attention and memory evaluation across the life span: heterogeneous effects of age and education.

    Science.gov (United States)

    Gómez-Pérez, Esther; Ostrosky-Solís, Feggy

    2006-05-01

    The developmental sequences of attention and memory were studied by utilizing normative data derived from the neuropsychological battery named NEUROPSI ATTENTION AND MEMORY. A sample of 521 Spanish-speaking individuals, aged 6 to 85 years, participated in this study. In the adult sample, educational level ranged from 0 to 22 years of education. Data from subtests measuring orientation, attention and concentration, executive functions, working memory, immediate and delayed verbal memory, and immediate and delayed visual memory were included. The factor structure of the analyzed battery is presented. The effects of age and education on this structure were analyzed. Results suggested that although attention and memory are related, their developmental sequences are separated from one another. During childhood, the development of selective and sustained attention, attentional-working memory, and executive functions showed a fast improvement in performance. Development of verbal memory and place and person orientation showed a slower increment in scores. In the adult sample it was found that factors related to memory are sensitive to age, whereas those related to attention and executive functions are sensitive to education. The consideration of both the developmental sequence, as well as differential effects of education, can improve the sensitivity and specificity of neuropsychological measures, allowing early diagnosis of cognitive dysfunction and implementation of adequate rehabilitation programs.

  9. Aging is associated with decreased maximal life span and accelerated senescence of bone marrow stromal cells

    DEFF Research Database (Denmark)

    Dokkedahl, Karin Stenderup; Justesen, Jeannette; Clausen, Christian

    2003-01-01

    donors were able to form similar amounts of mineralized matrix in vitro and of normal lamellar bone in vivo. In adipogenic medium similar numbers of adipocytes formed in cultures of young and old donors. In conclusion, aging is associated with decreased proliferative capacity of osteoprogenitor cells......Age-related decrease in bone formation is well described. However, the cellular causes are not known. Thus, we have established cultures of bone marrow stromal cells (MSC) from young (aged 18-29 years, n = 6) and old (aged 68-81 years, n = 5) donors. MSC were serially passaged until reaching......, suggesting that decreased osteoblastic cell number, and not function, leads to age-related decrease in bone formation....

  10. Perceptions of rapport across the life span: Gaze patterns and judgment accuracy.

    Science.gov (United States)

    Vicaria, Ishabel M; Bernieri, Frank J; Isaacowitz, Derek M

    2015-06-01

    Although age-related deficits in emotion perception have been established using photographs of individuals, the extension of these findings to dynamic displays and dyads is just beginning. Similarly, most eye-tracking research in the person perception literature, including those that study age differences, have focused on individual attributes gleaned from static images; to our knowledge, no previous research has considered cue use in dyadic judgments with eye-tracking. The current study employed a Brunswikian lens model analysis in conjunction with eye-tracking measurements to study age differences in the judgment of rapport, a social construct comprised of mutual attentiveness, positive feelings, and coordination between interacting partners. Judgment accuracy and cue utilization of younger (n = 47) and older (n = 46) adults were operationalized as correlations between a perceiver's judgments and criterion values within a set of 34 brief interaction videos in which 2 opposite sex college students discussed a controversial topic. No age differences emerged in the accuracy of judgments; however, pathways to accuracy differed by age: Younger adults' judgments relied on some behavioral cues more than older adults. In addition, eye-tracking analyses revealed that older adults spent more time looking at the bodies of the targets in the videos, whereas younger adults spent more time looking at the targets' heads. The contributions from both the lens model and eye-tracking findings provide distinct but complementary insights to our understanding of age-related continuities and shifts in social perceptual processing.

  11. Life Span Differences in Electrophysiological Correlates of Monitoring Gains and Losses during Probabilistic Reinforcement Learning

    Science.gov (United States)

    Hammerer, Dorothea; Li, Shu-Chen; Muller, Viktor; Lindenberger, Ulman

    2011-01-01

    By recording the feedback-related negativity (FRN) in response to gains and losses, we investigated the contribution of outcome monitoring mechanisms to age-associated differences in probabilistic reinforcement learning. Specifically, we assessed the difference of the monitoring reactions to gains and losses to investigate the monitoring of…

  12. Emotional reactivity across the adult life span: the cognitive pragmatics make a difference.

    Science.gov (United States)

    Kunzmann, Ute; Richter, David

    2009-12-01

    Previously, we found that during films about age-typical losses, older adults experienced greater sadness than young adults, whereas their physiological responses were just as large. In the present study, our goal was to replicate this finding and extend past work by examining the role of cognitive functioning in age differences in emotional reactivity. We measured the autonomic and subjective responses of 240 adults (age range=20 to 70) while they viewed films about age-typical losses from our previous work. Findings were fully supportive of our past work: The magnitude of subjective reactions to our films increased linearly over the adult years, whereas there were no age differences on the level of physiological reactivity. We also found that the subjective reactions of adults with high pragmatic intelligence were of moderate size independent of their own age or the age relevance of the emotion elicitor. In contrast, the subjective reactions of adults low on pragmatic intelligence were more variable. Together, this evidence suggests that research on age differences in emotional reactivity may benefit from a perspective that considers individual difference variables as well as contextual variations.

  13. Getting Older, Getting Better? Personal Strivings and Psychological Maturity across the Life Span.

    Science.gov (United States)

    Sheldon, Kennon M.; Kasser, Tim

    2001-01-01

    Examined psychological maturity based on personal strivings in 108 adults ages 17 to 82 years. Results supported hypotheses that older people would list more strivings concerning generativity and ego integrity and fewer strivings concerning identity and intimacy, and that maturity and age would be positively associated with subjective well-being.…

  14. Sex Segregation in Friendships and Normative Contexts across the Life Span

    Science.gov (United States)

    Mehta, Clare M.; Strough, JoNell

    2009-01-01

    Sex segregation (the separation of boys and girls into same-sex groups in their friendships and casual encounters; [Thorne, B., & Luria, Z. (1986). Sexuality and gender in children's daily worlds. "Social Problems, 33", 176-190]), has typically been viewed as a childhood phenomenon. In the present paper, we review research that suggests the…

  15. Life Span Studies of ADHD-Conceptual Challenges and Predictors of Persistence and Outcome

    DEFF Research Database (Denmark)

    Caye, Arthur; Swanson, James; Thapar, Anita

    2016-01-01

    . Evidence indicates that ADHD severity, comorbid conduct disorder and major depressive disorder, and treatment for ADHD are the main predictors of ADHD persistence from childhood to adulthood. Comorbid conduct disorder and ADHD severity in childhood are the most important predictors of adverse outcomes......There is a renewed interest in better conceptualizing trajectories of attention-deficit/hyperactivity disorder (ADHD) from childhood to adulthood, driven by an increased recognition of long-term impairment and potential persistence beyond childhood and adolescence. This review addresses...... the following major issues relevant to the course of ADHD in light of current evidence from longitudinal studies: (1) conceptual and methodological issues related to measurement of persistence of ADHD, (2) estimates of persistence rate from childhood to adulthood and its predictors, (3) long-term negative...

  16. The Status of Several Conservation Abilities Across the Life-Span

    Science.gov (United States)

    Papalia, Diane E.

    1972-01-01

    Although the ability to conserve number held up well with age, quantity conservation performance was generally lower in the subjects over 65 years of age than in the college and adult age groups. (Author)

  17. Object recognition in congruent and incongruent natural scenes: a life-span study.

    Science.gov (United States)

    Rémy, F; Saint-Aubert, L; Bacon-Macé, N; Vayssière, N; Barbeau, E; Fabre-Thorpe, M

    2013-10-18

    Efficient processing of our complex visual environment is essential and many daily visual tasks rely on accurate and fast object recognition. It is therefore important to evaluate how object recognition performance evolves during the course of adulthood. Surprisingly, this ability has not yet been investigated in the aged population, although several neuroimaging studies have reported altered activity in high-level visual ventral regions when elderly subjects process natural stimuli. In the present study, color photographs of various objects embedded in contextual scenes were used to assess object categorization performance in 97 participants aged from 20 to 91. Objects were either animals or pieces of furniture, embedded in either congruent or incongruent contexts. In every age group, subjects showed reduced categorization performance, both in terms of accuracy and speed, when objects were seen in incongruent vs. congruent contexts. In subjects over 60 years old, object categorization was greatly slowed down when compared to young and middle-aged subjects. Moreover, subjects over 75 years old evidenced a significant decrease in categorization accuracy when objects were seen in incongruent contexts. This indicates that incongruence of the scene may be particularly disturbing in late adulthood, therefore impairing object recognition. Our results suggest that daily visual processing of complex natural environments may be less efficient with age, which might impact performance in everyday visual tasks.

  18. Etiology of Obesity Over the Life Span: Ecologic and Genetic Highlights from New Zealand Cohorts.

    Science.gov (United States)

    Poppitt, S D; Silvestre, M P; Liu, A

    2014-03-01

    The origins of the New Zealand population are highly diverse. New Zealand Māori are the indigenous peoples with a population of approximately half a million (~12 %), with the remainder comprising predominantly European/Caucasian (~50 %), Pacific Island Polynesian (~28 %) and Asian (~10 %) peoples. With a prevalence of overweight and obesity of 65 % for adults >15 years of age, of which 28 % have a BMI > 30 kg/m(2), New Zealand has been ranked third highest in a global OECD obesity review, behind only the US and Mexico. Levels of childhood obesity are also significant, with 31 % of New Zealand's children either overweight or obese. Few gender differences exist, but there are significant differences between ethnicities (Asian > European Caucasian > Māori > Pacific) with disproportionate representation by those poorer and with less formal education. A high 62 % of Pacifika are obese and virtually the entire adult population has a BMI >25 kg/m(2). Public health measures to limit progressive increases in weight are unsuccessful, and clearly should be priority for government focused on disease prevention.

  19. Mortality theory used to predict the life-span shortening caused by chronic internal irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Panteleev, L.I.; Shvedov, V.L. (Institut Biofiziki, Moscow (USSR))

    In experiments on albino rats received strontium 90 in daily doses of 1.85 to 185 kBq/day the regularities of death were studied. It was shown that death of animals exposed to chronic internal radiation followed the Gomperz B. mortality law.

  20. Down syndrome, Turner syndrome, and Klinefelter syndrome: primary care throughout the life span.

    Science.gov (United States)

    Tyler, Carl; Edman, Jennifer C

    2004-09-01

    Down syndrome, Turner syndrome, and Klinefelter syndrome constitute the most common chromosomal abnormalities encountered by primary care physicians. Down syndrome typically is recognized at birth, Turner syndrome often is not recognized until adolescence,and many men with Klinefelter syndrome are never diagnosed. Although each syndrome is caused by an abnormal number of chromosomes, or aneuploidy, they are distinct syndromes with learning disabilities and a predisposition toward autoimmune diseases,endocrinologic disorders, and cancers. Optimal health care requires a thorough knowledge of the unique health risks, psychoeducational needs, functional capabilities, and phenotypic variation associated with each condition. Syndrome-specific health care should complement standard preventive health care recommendations. Checklists and syndrome-specific growth grids should be used. Ongoing communication between specialists and primary care physicians and between pediatric and adult clinicians is essential. Support groups and Internet resources can benefit affected individuals and their families immensely.

  1. Brain plasticity through the life span: learning to learn and action video games.

    Science.gov (United States)

    Bavelier, Daphne; Green, C Shawn; Pouget, Alexandre; Schrater, Paul

    2012-01-01

    The ability of the human brain to learn is exceptional. Yet, learning is typically quite specific to the exact task used during training, a limiting factor for practical applications such as rehabilitation, workforce training, or education. The possibility of identifying training regimens that have a broad enough impact to transfer to a variety of tasks is thus highly appealing. This work reviews how complex training environments such as action video game play may actually foster brain plasticity and learning. This enhanced learning capacity, termed learning to learn, is considered in light of its computational requirements and putative neural mechanisms.

  2. Human breast microvascular endothelial cells retain phenotypic traits in long-term finite life span culture

    DEFF Research Database (Denmark)

    Sigurdsson, Valgardur; Fridriksdottir, Agla J R; Kjartansson, Jens

    2007-01-01

    uptake of low-density lipoprotein, and had E-selectin induced upon treatment with tumor necrosis factor-alpha. The first signs of senescence in passage 14 were accompanied by gain of trisomy 11. At passage 18 cells showed chromosomal aberrations and growth arrest as revealed by beta...

  3. Changes in anti-Müllerian hormone (AMH) throughout the life span

    DEFF Research Database (Denmark)

    Aksglaede, L; Sørensen, K; Boas, M;

    2010-01-01

    Anti-Müllerian hormone (AMH), which is secreted by immature Sertoli cells, triggers the involution of the fetal Müllerian ducts. AMH is a testis-specific marker used for diagnosis in infants with ambiguous genitalia or bilateral cryptorchidism.......Anti-Müllerian hormone (AMH), which is secreted by immature Sertoli cells, triggers the involution of the fetal Müllerian ducts. AMH is a testis-specific marker used for diagnosis in infants with ambiguous genitalia or bilateral cryptorchidism....

  4. Awareness, Perceptions, and Communication Needs about the Affordable Care Act across the Life Span

    Science.gov (United States)

    Bergeron, Caroline D.; Friedman, Daniela B.; Sisson, Diana C.; Tanner, Andrea; Kornegay, Vance L.; Owens, Otis L.; Weis, Megan A.; Patterson, Lee L.

    2016-01-01

    Background: By March 2014, all U.S. citizens were required to have health insurance according to the Affordable Care Act (ACA). Purpose: Study objectives were to explore individuals' opinions, perceptions, and communication sources and needs about the ACA and to assess differences by age group. Methods: In November 2013, 10 1-hour focus groups (5…

  5. Life-Span Trajectory of Self-Esteem Development: A Myth or Reality

    Science.gov (United States)

    Badayai, Abdul Rahman bin Ahmad; Ismail, Khaidzir bin Haji

    2012-01-01

    Self-esteem has been regarded as one of the most pivotal component in almost every day human daily activities. Trajectory of self esteem development means that on the average, one's self-esteem is relatively high in childhood, then drops during adolescence, later to arise gradually throughout adulthood, and then declines sharply in old age. The…

  6. Life Span Transitions for a Student with LD: Mother-Daughter Perspectives

    Science.gov (United States)

    Cumming, Therese M.; Smedley, Emily N.

    2017-01-01

    Transition planning and processes can greatly influence the quality of schooling transitions for students with learning disabilities. Student-focused planning and family involvement are two integral components of transition planning that do not always receive the emphasis that they deserve. The educational transitions of one student are examined…

  7. Etiology of Obesity Over the Life Span: Ecological and Genetic Highlights from Asian Countries.

    Science.gov (United States)

    Chong, Pei Nee; Teh, Christinal Pey Wen; Poh, Bee Koon; Noor, Mohd Ismail

    2014-03-01

    Obesity is a worldwide pandemic, and the prevalence rate has doubled since the 1980s. Asian countries are also experiencing the global epidemic of obesity with its related health consequences. The prevalence of overweight and obesity are increasing at an alarming rate across all age groups in Asia. These increases are mainly attributed to rapid economic growth, which leads to socio-economic, nutrition and lifestyle transitions, resulting in a positive energy balance. In addition, fat mass and obesity-associated gene variants, copy number variants in chromosomes and epigenetic modifications have shown positive associations with the risk of obesity among Asians. In this review highlights of prevalence and related ecological and genetic factors that could influence the rapid rise in obesity among Asian populations are discussed.

  8. Carbaryl neurotoxicity across the life-span of the Brown-Norway rat

    Science.gov (United States)

    Demographics show that the proportion of older adults is increasing every year. While there has been considerable attention paid to potential sensitivity of the young to environmental chemicals, there is much less known about the relative vulnerability of the aged. Differences in...

  9. The two sides of sensory-cognitive interactions: effects of age, hearing acuity, and working memory span on sentence comprehension

    Directory of Open Access Journals (Sweden)

    Renee eDeCaro

    2016-02-01

    Full Text Available Reduced hearing acuity is among the most prevalent of chronic medical conditions among older adults. An experiment is reported in which comprehension of spoken sentences was tested for older adults with good hearing acuity or with a mild-to-moderate hearing loss, and young adults with age-normal hearing. Comprehension was measured by participants’ ability to determine of the agent of an action in sentences that expressed this relation with a syntactically less complex subject-relative construction or a syntactically more complex object-relative construction. Agency determination was further challenged by inserting a prepositional phrase into sentences between the person performing an action and the action being performed. As a control, prepositional phrases of equivalent length were also inserted into sentences in a non-disruptive position. Effects on sentence comprehension of age, hearing acuity, prepositional phrase placement and sound level of stimulus presentations appeared only for comprehension of sentences with the more syntactically complex object-relative structures. Working memory as tested by reading span scores accounted for a significant amount of the variance in comprehension accuracy. Once working memory capacity and hearing acuity were taken into account, chronological age among the older adults contributed no further variance to comprehension accuracy. Results are discussed in terms of the positive and negative effects of sensory-cognitive interactions in comprehension of spoken sentences and lend support to a framework in which domain-general executive resources, notably verbal working memory, play a role in both linguistic and perceptual processing.

  10. Archaeointensity results spanning the past 6 kiloyears from eastern China and implications for extreme behaviors of the geomagnetic field

    Science.gov (United States)

    Cai, Shuhui; Jin, Guiyun; Tauxe, Lisa; Deng, Chenglong; Qin, Huafeng; Pan, Yongxin; Zhu, Rixiang

    2017-01-01

    Variations of the Earth’s geomagnetic field during the Holocene are important for understanding centennial to millennial-scale processes of the Earth’s deep interior and have enormous potential implications for chronological correlations (e.g., comparisons between different sedimentary recording sequences, archaeomagnetic dating). Here, we present 21 robust archaeointensity data points from eastern China spanning the past ˜6 kyr. These results add significantly to the published data both regionally and globally. Taking together, we establish an archaeointensity reference curve for Eastern Asia, which can be used for archaeomagnetic dating in this region. Virtual axial dipole moments (VADMs) of the data range from a Holocene-wide low of ˜27 to “spike” values of ˜166 ZAm2 (Z: 1021). The results, in conjunction with our recently published data, confirm the existence of a decrease in paleointensity (DIP) in China around ˜2200 BCE. These low intensities are the lowest ever found for the Holocene and have not been reported outside of China. We also report a spike intensity of 165.8 ± 6.0 ZAm2 at ˜1300 BCE (±300 y), which is either a prelude to or the same event (within age uncertainties) as spikes first reported in the Levant.

  11. Protocol adaptations to conduct Systematic Literature Reviews in Software Engineering: a chronological study

    Directory of Open Access Journals (Sweden)

    Samuel Sepúlveda

    2015-12-01

    Full Text Available Systematic literature reviews (SLR have reached a considerable level of adoption in Software Engineering (SE, how-ever protocol adaptations for its implementation remain tangentially addressed. This work provides a chronological framework for the use and adaptation of the SLR protocol, including its current status. A systematic literature search was performed, reviewing a set of twelve articles being selected in accordance with the inclusion and exclusion criteria between 2004 and 2013, using digital data sources recognized by the SE community. A chronological framework is provided that includes the current state of the protocol adaptations to conduct SLR in SE. The results indicate areas where the quantity and quality of investigations needs to be increased and the identi- fication of the main proposals providing adaptations for the protocol conducting SLR in SE.

  12. Chronology of Postglacial Eruptive Activity and Calculation of Eruption Probabilities for Medicine Lake Volcano, Northern California

    Science.gov (United States)

    Nathenson, Manuel; Donnelly-Nolan, Julie M.; Champion, Duane E.; Lowenstern, Jacob B.

    2007-01-01

    Medicine Lake volcano has had 4 eruptive episodes in its postglacial history (since 13,000 years ago) comprising 16 eruptions. Time intervals between events within the episodes are relatively short, whereas time intervals between the episodes are much longer. An updated radiocarbon chronology for these eruptions is presented that uses paleomagnetic data to constrain the choice of calibrated ages. This chronology is used with exponential, Weibull, and mixed-exponential probability distributions to model the data for time intervals between eruptions. The mixed exponential distribution is the best match to the data and provides estimates for the conditional probability of a future eruption given the time since the last eruption. The probability of an eruption at Medicine Lake volcano in the next year from today is 0.00028.

  13. [The influence of alcohol consumption on the chronological patterns of sudden cardiac death].

    Science.gov (United States)

    Sapozhnikov, S P; Kozlov, V A; Golenkov, A V; Kichigin, V A; Karyshev, P B; Samarkina, O Yu

    2015-01-01

    The objective of the present study was the retrospective analysis of the materials collected by the Republican Bureau of Forensic Medical Expertise, Ministry of Health and Social Development of Chuvash Republic, during the period from 1997 till 2002 for the elucidation of the chronological patterns of sudden cardiac death (SCD) associated with alcohol consumption depending on the sex and age of the victims, days of the week and months of the year as well as weather conditions. It was shown that the peak of mortality among men and women taking no alcohol fell on Monday. It was highest in May and decreased by February. The alcohol consumption significantly changes the chronological patterns of mortality from cardiovascular pathology. It was highest among the women abusing alcohol in August and October. The study has demonstrated a weak negative correlation between the frequency of sudden cardiac death among non-consumers of alcohol and dew-point temperature among the persons having alcohol in blood.

  14. Energy History Chronology from World War II to the Present [1982

    Science.gov (United States)

    Dean, P. C.

    1982-08-01

    This report provides a basic guide to the major Presidential, Legislative, Judicial, and Federal agency actions relating to energy policy, research, development, and regulation in recent years. The chronology is arranged synoptically, allowing users to reference easily the historical context in which each event occurred. Summaries of Presidential, Legislative, and Judicial actions relating to energy, rosters of federal energy officials, and a genealogy of federal energy agencies are also provided in separate appendices. The Energy History Chronology was prepared in conjunction with the History Division's series of pamphlets on the Institutional Origins of the Department of Energy. The series includes concise histories of the Department of Energy, the Energy Research and Development Administration, the Federal Energy Administration, and the Atomic Energy Commission. All significant events and achievements noted in the institutional history are also listed.

  15. An optical age chronology of Late Pleistocene fluvial deposits in the northern lower Mississippi valley

    Science.gov (United States)

    Rittenour, Tammy M.; Goble, Ronald J.; Blum, Michael D.

    2003-05-01

    The lower Mississippi valley (LMV) contains many large braided channel belts that are preserved west of the Holocene floodplain. Previous efforts to establish geochronologic control on channel-belt construction have been hindered by the lack of organic material for radiocarbon dating. Luminescence techniques provide a burial date for the sediment itself and may prove useful in this context. Samples from three channel belts in the northern LMV were analyzed using the single aliquot-regenerative technique on 90-125 μm quartz. Optical ages (19.7-17.8, 16.1-15.0 and 12.5-12.1 ka) are consistent with geomorphic relationships and indicate that channel belts were formed in the late Pleistocene under glacial conditions. These optical ages provide the first detailed chronology of LMV channel-belt formation and are the first step towards developing a chronology for the entire LMV.

  16. A Date Recovery System launched for chronological studies in ancient China

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Benefited from the performance of the Xia-Shang-Zhou Chronology Project (XSZP) in China and our new astronomical chronology method designed and processed for Chinese particular 60-day-cycle Ganzhi (the heavenly stems and earthly branches) date records, we launch a Date Recovery System (DRS) for ancient China. Of high analysis function, this software can recover and convert the complete or incomplete date information originally from Ganzhi style in the historical period of China to the Gregorian Calendar System, which may have wide applications in the area of literary history, archaeology and cultural relic, etc., and solve the Goldbach Puzzles of Chinese nations. As an example, we give the detailed process for the sculptures on four bronze wares with the Ganzhi data and afterwards employ this software and provide their possible dates corresponding to Gregorian system.

  17. A Date Recovery System launched for chronological studies in ancient China

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Benefited from the performance of the Xia-Shang-Zhou Chronology Project(XSZP) in China and our new astronomical chronology method designed and processed for Chinese particular 60-day-cycle Ganzhi(the heavenly stems and earthly branches)date records,we launch a Date Recovery System(DRS)for ancient China. Of high analysis function,this software can recover and convert the complete or incomplete date information originally from Ganzhi style in the historical period of China to the Gregorian Calendar System,which may have wide applications in the area of literary history,archaeology and cultural relic,etc.,and solve the Goldbach Puzzles of Chinese nations.As an example,we give the detailed process for the sculptures on four bronze wares with the Ganzhi data and afterwards employ this software and provide their possible dates corresponding to Gregorian system.

  18. Comparison of the glacial chronology of Eastern Baffin Island, East Greenland and Camp century accumulation record

    DEFF Research Database (Denmark)

    Andrews, John; Funder, Svend Visby; Hjort, Chritian;

    1974-01-01

    level between 120,000 and 70,000 B.P. may well be related to glacierization of high arctic land masses under conditions of heavy snowfall. The subsequent reduction of accumulation in these high arctic areas then leads to a reduction of ice volume with a dry, cold interstadial correlative in time......Independently derived glacial chronologies from eastern Baffin Island, Canadian Arctic, and from East Greenland show essentially similar glaciologic trends that arc notably different from the response of the southern margins of the Laurentide and FCllnoscandia Ice Sheets. The critical aspe......~ts of both chronologies and the related extcn t of the ice sheets are (1) an early and maximum glacial stade, during the early phase of the last glaciation, reaching its peak abqut 100,000 to 75,000 yr ago; (2) an in terstadial about .70,000 n.p.; (3) an ice advance peaking about 45,000 yr ago; (4...

  19. On the chronology of lunar origin and evolution. Implications for Earth, Mars and the Solar System as a whole

    Science.gov (United States)

    Geiss, Johannes; Rossi, Angelo Pio

    2013-11-01

    terrestrial planets, including Mars and possibly early Earth. The Moon holds a historic record of Galactic cosmic-ray intensity, solar wind composition and fluxes and composition of solids of any size in the region of the terrestrial planets. Some of this record has been deciphered. Secular mixing of the Sun was constrained by determining 3He/4He of solar wind helium stored in lunar fines and ancient breccias. For checking the presumed constancy of the impact rate over the past ≈3.1 Ga, samples of the youngest mare basalts would be needed for determining their radiometric ages. Radiometric dating and stratigraphy has revealed that many of the large basins on the near side of the Moon were created by impacts about 4.1 to 3.8 Ga ago. The apparent clustering of ages called "Late Heavy Bombardment (LHB)" is thought to result from migration of planets several 100 million years after their accretion. The bombardment, unexpectedly late in solar system history, must have had a devastating effect on the atmosphere, hydrosphere and habitability on Earth during and following this epoch, but direct traces of this bombardment have been eradicated on our planet by plate tectonics. Indirect evidence about the course of bombardment during this epoch on Earth must therefore come from the lunar record, especially from additional data on the terminal phase of the LHB. For this purpose, documented samples are required for measuring precise radiometric ages of the Orientale Basin and the Nectaris and/or Fecunditatis Basins in order to compare these ages with the time of the earliest traces of life on Earth. A crater count chronology is presently being built up for planet Mars and its surface features. The chronology is based on the established lunar chronology whereby differences between the impact rates for Moon and Mars are derived from local fluxes and impact energies of projectiles. Direct calibration of the Martian chronology will have to come from radiometric ages and cosmic-ray exposure

  20. 复杂悬跨条件下的管线涡激振动分析%VIV analysis of pipelines under complex span conditions

    Institute of Scientific and Technical Information of China (English)

    James WANG; F. Steven WANG; Gang DUAN; Paul JUKES

    2009-01-01

    Spans occur when a pipeline is laid on a rough undulating seabed or when upheaval buckling occurs due to constrained thermal expansion. This not only results in static and dynamic loads on the flowline at span sections, but also generates vortex induced vibration (VIV), which can lead to fatigue issues. The phenomenon, if not predicted and controlled properly, will negatively affect pipeline integrity, leading to expensive remediation and intervention work. Span analysis can be complicated by: long span lengths, a large number of spans caused by a rough seabed, and multi-span interactions. In addition, the complexity can be more onerous and challenging when soil uncertainty, concrete degradation and unknown residual lay tension are considered in the analysis. This paper describes the latest developments and a .state-of-the-art. finite element analysis program that has been developed to simulate the span response of a flowline under complex boundary and loading conditions. Both VIV and direct wave loading are captured in the analysis and the results are sequentially used for the ultimate limit state (ULS) check and fatigue life calculation.