scholarly journals COMPENSATION EFFECT OF MORTALITY: A CHALLENGE TO LIFE EXTENSION

2019 ◽  
Vol 3 (Supplement_1) ◽  
pp. S966-S967
Author(s):  
Natalia S Gavrilova ◽  
Leonid Gavrilov
Keyword(s):  
Life Span ◽  
Compensation Effect ◽  
Life Extension ◽  
Slope Parameter ◽  
Aging Rate ◽  
Convergence Point ◽  
Gompertz Law ◽  
The 1960S ◽  
The Stability ◽  
Species Specific

Abstract In order to develop genuine anti-aging interventions it is important to find the best estimate of the aging rate in humans, which is often measured as a slope parameter of the Gompertz law. The compensation effect of mortality (CEM), refers to mortality convergence, when higher values for the slope parameter are compensated by lower values of the intercept parameter (initial mortality) in different populations of a given species. The age of this convergence point is called the "species-specific life span". Due to CEM, factors associated with life span extension are usually accompanied by paradoxical increase in actuarial aging rate. We evaluated the stability of CEM by analyzing the United Nations abridged life tables for 241 countries and regions and estimating parameters of the Gompertz-Makeham model using method of non-linear regression in the age interval 30-80 years. We found that the species-specific lifespan is equal to 94.5 ± 0.5 years, which is the same as reported in the past for years before the 1960s: 95 ± 3 years (Gavrilov, Gavrilova, 1991). Thus, the convergence point of CEM is stable despite significant mortality decline over past 50 years and is not affected by factors decreasing mortality at younger ages. Populations deviating from CEM with apparently slow aging (with both slow actuarial aging rate and low intercept parameter) have been identified. The existence of CEM in mice (ITP data) allowed us to find interventions that are able to both extend lifespan and slow the actuarial aging rate giving promise for radical life extension.

Stability of Horizontal Boundary Layers

2006 ◽  
Author(s):  
Jean-Yves Chemin ◽  
Benoit Desjardins ◽  
Isabelle Gallagher ◽  
Emmanuel Grenier
Keyword(s):  
Reynolds Number ◽  
Linear Stability ◽  
Mathematical Proof ◽  
Vertical Component ◽  
Ekman Layer ◽  
Numerical Results ◽  
Energy Estimates ◽  
Navier Stokes ◽  
The 1960S ◽  
The Stability

Let us now detail the stability properties of an Ekman layer introduced in Part I, page 11. First we will recall how to compute the critical Reynolds number. Then we will describe briefly what happens at larger Reynolds numbers. The first step in the study of the stability of the Ekman layer is to consider the linear stability of a pure Ekman spiral of the form where U∞ is the velocity away from the layer and ζ is the rescaled vertical component ζ = x3/√εν. The corresponding Reynolds number is Let us consider the Navier–Stokes–Coriolis equations, linearized around uE The problem is now to study the (linear) stability of the 0 solution of the system (LNSCε). If u=0 is stable we say that uE is linearly stable, if not we say that it is linearly unstable. Numerical results show that u=0 is stable if and only if Re<Rec where Rec can be evaluated numerically. Up to now there is no mathematical proof of this fact, and it is only possible to prove that 0 is linearly stable for Re<Re1 and unstable for Re>Re2 with Re1<Rec<Re2, Re1 being obtained by energy estimates and Re2 by a perturbative analysis of the case Re=∞. We would like to emphasize that the numerical results are very reliable and can be considered as definitive results, since as we will see below, the stability analysis can be reduced to the study of a system of ordinary differential equations posed on the half-space, with boundary conditions on both ends, a system which can be studied arbitrarily precisely, even on desktop computers (first computations were done in the 1960s by Lilly).

scholarly journals New Edible Packaging Material with Function in Shelf Life Extension: Applications for the Meat and Cheese Industries

Foods ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 562
Author(s):  
Roxana Gheorghita (Puscaselu) ◽  
Sonia Amariei ◽  
Liliana Norocel ◽  
Gheorghe Gutt
Keyword(s):  
Food Industry ◽  
Microbial Growth ◽  
Activity Index ◽  
Life Extension ◽  
Total Count ◽  
Initial Stage ◽  
Edible Packaging ◽  
New Material ◽  
The Stability ◽  
General Appearance

Nowadays, biopolymer films have gained notoriety among the packaging materials. Some studies clearly test their effectiveness for certain periods of time, with applicability in the food industry. This research has been carried out in two directions. Firstly, the development and testing of the new edible material: general appearance, thickness, retraction ratio, color, transmittance, microstructure, roughness, and porosity, as well as mechanical and solubility tests. Secondly, testing of the packaged products—slices of cheese and prosciutto—in the new material and their maintenance at refrigeration conditions for 5 months; thus, the peroxide index, color, and water activity index were evaluated for the packaged products. The results emphasize that the packaging is a lipophilic one and does not allow wetting or any changes in the food moisture. The results indicate the stability of the parameters within three months and present the changes occurring within the fourth and fifth months. Microbiological tests indicated an initial microbial growth, both for cheese slices and ham slices. Time testing indicated a small increase in the total count number over the 5-month period: 23 cfu/g were found of fresh slices of prosciutto and 27 cfu/g in the case of the packaged ones; for slices of cheese, the total count of microorganisms indicated 7 cfu/g in the initial stage and 11 cfu/g after 5 months. The results indicate that the film did not facilitate the growth of the existing microorganisms, and highlight the need to purchase food from safe places, especially in the case of raw-dried products that have not undergone heat treatment, which may endanger the health of the consumer. The new material tested represents a promising substitute for commercial and unsustainable plastic packaging.

Unstable heart rate and temperature regulation predict mortality in AKR/J mice

2003 ◽  
Vol 284 (3) ◽  
pp. R742-R750 ◽  
Author(s):  
Clarke G. Tankersley ◽  
Rafael Irizarry ◽  
Susan E. Flanders ◽  
Richard Rabold ◽  
Robert Frank
Keyword(s):  
Heart Rate ◽  
Life Span ◽  
Inbred Mice ◽  
Deep Body Temperature ◽  
Circadian Periodicity ◽  
Regulation Of Activity ◽  
Susceptibility Model ◽  
Imminent Death ◽  
The Stability ◽  
Deep Body

Elderly populations face greater risks of mortality when exposed to changes in environmental stress. The purpose of the following study was to develop an age-dependent susceptibility model that achieved the following three goals: 1) to operationally define homeostasis by assessing the stability and periodicity in physical activity, heart rate (HR), and deep body temperature (Tdb), 2) to specify alterations in activity, HR, and Tdb regulation that signal imminent death, and 3) to test the hypothesis that the decay in homeostasis associated with imminent death incorporates the coincident disintegration of multiple physiological systems. To achieve these goals, the circadian regulation of activity, HR, and Tdbwas assessed using radiotelemeters implanted in AKR/J ( n = 17) inbred mice at ∼190 days of age. During a 12:12-h light-dark cycle, weekly measurements were obtained at 30-min intervals for 48-h periods until each animal's natural death. The average (±SE) life span of surgically treated animals did not differ from untreated controls (319 ± 12 vs. 319 ± 14 days). Cardiac and thermal stability were characterized by a circadian periodicity, which oscillated around stable daily averages of 640 ± 14 beats/min in HR and 36.6 ± 0.1°C in Tdb. Stable HR and Tdb responses were compared with extreme conditions 3 days before death, during which a disintegration of circadian periodicity was coincident with a fall in the daily average HR and Tdb of ∼29 and ∼13% lower (i.e., 456 ± 22 beats/min and 31.7 ± 0.6°C), respectively. The results further suggested that multiple predictors of cardiac and thermal instability in AK mice, including significant bradycardia, hypothermia, and a loss of circadian periodicity, forecast life span 5–6 wk before expiration.

Actuarial Aging Rate Is Not Constant within the Human Life Span

Gerontology ◽  
1989 ◽  
Vol 35 (2-3) ◽  
pp. 113-120 ◽  
Author(s):  
Arkadii L. Ekonomov ◽  
Charles L. Rudd ◽  
Aleksey J. Lomakin
Keyword(s):  
Life Span ◽  
Human Life ◽  
Aging Rate ◽  
Human Life Span

Methodological considerations in estimating speed of cognitive operations

1995 ◽  
Vol 1 (1) ◽  
pp. 3-9 ◽  
Author(s):  
James T. Becker ◽  
Rocco Caldararo ◽  
Alan D. Baddeley ◽  
Mary Amanda Dew ◽  
William C. Heindel ◽  
...  
Keyword(s):  
Memory Task ◽  
Recognition Task ◽  
Psychological Theory ◽  
Item Recognition ◽  
Clinical Samples ◽  
Regression Equations ◽  
Item Recognition Task ◽  
The 1960S ◽  
The Stability ◽  
Methodological Considerations

AbstractIndividuals infected with Human Immunodeficiency Virus (HIV) and having cognitive impairment have been described as having slow mentation. Data supporting this proposition come from a variety of sources, including Sternberg's (1966) item recognition memory task. The procedure nominally provides an index of speed of mental operations, independent from input/output demands. However, since the original use of this procedure in the 1960s, advances in cognitive psychology have revealed many of its limitations. The purpose of the present study was to examine the psychometric characteristics of this task. Each participant performed the Sternberg item recognition task twice, 6 mo apart. The stability of the estimate of the slope of regression equations and for zero intercept ranged from excellent (r = .87) to poor (r = .30), and the data from many individual subjects could not be reliably modelled using multiple linear regression techniques. These data, as well as those from previous research, demonstrate the limited practical use of this task in clinical samples. Furthermore, as cognitive psychological theory has advanced in the past 30 yr, the conceptual underpinnings of the procedure have essentially evaporated. (JINS, 1995, 1, 3–9).

scholarly journals Evolution of Human Longevity and the Genetic Complexity Governing Aging Rate

2001 ◽  
Vol 2001 (1) ◽  
Author(s):  
Richard G. Cutler
Keyword(s):  
Life Span ◽  
Maximum Rate ◽  
Human Longevity ◽  
Maximum Life Span ◽  
Genetic Changes ◽  
Aging Rate ◽  
The Past ◽  
Time Period ◽  
Rate Of Increase ◽  
Genetic Complexity

The genetic complexity of processes governing the aging rate of humans was estimated by determining the maximum rate at which life-span has evolved along the hominid ancestral-descendant sequence. Maximum life-span potential was found to have increased approximately twofold over the past 3 million years, reaching a maximum rate of increase of 14 years per 100,000 years about 100,000 years ago. It is estimated that about 0.6% of the total functional genes have received substitutions leading to one or more adaptive amino acid changes during this 100,000-year time-period. This suggests that aging is not the result of the expression of a large number of independently acting processes. Instead, primary aging processes appear to exist in which only a few genetic changes are necessary to uniformly decrease the aging rate of many different physiological functions. Reproduced by permission. Richard G. Cutler, Evolution of Human Longevity and the Genetic Complexity Governing Aging Rate. Proc. Natl. Acad. Sci. U.S.A. 72 , 4664-4668 (1975).

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