1,721,100 research outputs found
Enhanced stress-induced senescence-response may increase species lifespan
Full text linkCellular senescence is a biological phenomenon that has received many interpretations since its original description by Hayflick and Moorhead in 1961. A hypothesis proposed over 40 years ago is now generally accepted: i.e. that cellular senescence is a regulated cellular program. For the majority of forms of senescence, the senescence program seems to be induced due to the prolonged presence of DNA damage [1]...
pratense
No full textPilosella caespitosa (Dumortier) P.D. Sell & C. WestHieracium pratenseCemetery, N. Maple St., Florence (Northampton)grassy areaLupinus perenni
Obesity may accelerate the aging process
Full text linkLines of evidence from several studies have shown that increases in life expectancy are now accompanied by increased disability rate. The expanded lifespan of the aging population imposes a challenge on the continuous increase of chronic disease. The prevalence of overweight and obesity is increasing at an alarming rate in many parts of the world. Further to increasing the onset of metabolic imbalances, obesity leads to reduced life span and affects cellular and molecular processes in a fashion resembling aging. Nine key hallmarks of the aging process have been proposed. In this review, we will review these hallmarks and discuss pathophysiological changes that occur with obesity, that are similar to or contribute to those that occur during aging. We present and discuss the idea that obesity, in addition to having disease-specific effects, may accelerate the rate of aging affecting all aspects of physiology and thus shortening life span and health span
Development and Longevity: Cellular and Molecular Determinants - A Mini-Review
Full text linkAcross species, development and longevity are tightly linked. We discuss the relevant literature and suggest that the root for this stringent relationship is the rate of development. The basis for the relationship between rate of development and longevity lies in adaptations that have occurred through evolution at multiple levels of biological complexity: organism, organ, cellular, and molecular. Thus, the analysis of the relationship is of interest for multiple fields of biology
Life-Span Extension Single-Cell Organisms to Man Series: Aging Medicine
No full textIn recent years, remarkable discoveries have been made concerning the underlying mechanisms of aging. In Life-Span Extension: Single-Cell Organisms to Man, the editors bring together a range of illuminating perspectives from researchers investigating the aging process in a variety of species. This novel work addresses the aging process in species ranging from yeast to man and, among other subjects, features detailed discussions of the naked mole-rat, an exceptionally long-lived rodent; the relationship between dietary factors/food restriction and aging; and an evolutionary view of the human aging process.
Single mutations that extend life span have been identified in yeast, worms, flies, and mice, whereas studies in humans have identified potentially important markers for successful aging. At the same time, it has been discovered that the genes and pathways identified in these studies involve a surprisingly small set of conserved functions, most of which have been the focus of aging research for some time. For example, the mTOR pathway, a regulator of translation and protein synthesis, has been identified as a common longevity pathway in yeast and Caenorhabditis elegans. In mammals, this pathway intersects with neuroendocrine pathways and with the insulin/insulin-like growth factor pathways, which have been identified as major modulators of life span and aging in both invertebrates and mice.
Novel, emerging technologies and the increasingly wide variety of systems that are now used to study aging and the mechanisms of aging provide enormous opportunities for the identification of common pathways that modulate longevity. It is these common pathways that are the focus of this important volume.
Written for:
Gerontologists, geriatricians, pathologists
Table of contents
Reprogramming Cell Survival and Longevity: The role of Tor, Sch9, Ras, and Sir2.- Common Aging Mechanisms: Energy Metabolism and Longevity in Caenorhabditis elegans.- Conserved Mechanisms of Life-Span Regulation and Extension in Caenorhabditis elegans.- Drosophila melanogaster.- Overview of the Genetic Architecture of Longevity.- Mild Stress and Life Extension in Drosophila melanogaster.- Rodents.- Global Food Restriction.- Growth Hormone and Aging in Mice.- Comparative Biology of Aging.- Exploiting Natural Variation in Life Span To Evaluate Mechanisms of Aging.- Slow aging: Insights from An Exceptionally Long-Lived Rodent, the Naked Mole-Rat.- Life Extension in the Short-lived Fish Nothobranchius furzeri.- Aging in Humans.- Aging and Longevity in Animal Models and Humans.- Human aging and longevity within an evolutionary perspective
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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