460,935 research outputs found
Modeling Longevity Risk using Extreme Value Theory: An Empirical Investigation using Portuguese and Spanish Population Data
Extreme value theory (EVT) provides a framework to formalize the study of behaviour
in the tails of a distribution. In this paper we use EVT to model the statistical behaviour
of mortality rates over a given high threshold age and to estimate the significance of rare
longevity risk in a given population. We adopt a piecewise approach in estimating the
optimal threshold age using an iterative algorithm of maximum likelihood estimation.that
statistically determines the cut-off between the central (Gompertz) part of the distribution
and the upper tail modelled using the generalized Pareto distribution. The model is
empirically tested using the most recent period mortality data for the total, male and
female populations of Portugal and Spain. We use some classical results from EVT
to estimate the evolution of the theoretical maximum life span over time and to derive
confidence intervals for the central estimates. We then use time series methods to forecast
the highest attained age. We observe a good fit of the model in all populations and
subperiods analysed and on the whole life span considered. We estimate an increase in
the theoretical maximum life span over time for all populations, more significant in the
male subpopulations
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Driving in the wrong lane: towards a longer life-span of cars
Within the context of product longevity, one especially impactful and ubiquitous product demands further research: the car. Car longevity has been addressed in the context of product life extension and product lifetime optimisation but there have been a few studies on car longevity in the context of business and none specifically from an industrial design context. This paper presents initial findings from preliminary interviews with key industry representatives such as car designers and engineers. It discusses the barriers to and opportunities for designing a car with a longer life-span. This and further data will later be analysed in order to produce a design framework to inform car
designers on life-span and usage optimization through design. Strategies such as increased longevity or use-intensity can potentially reduce the throughput - and thereafter the consumption - of cars. Such a shift in the automotive sector would support the transition from a linear economy to a more sustainable one. The initial findings, however, suggest that a longer life car is not an uncompromised solution and important concessions would have to be made in order to make this an acceptable
product
Sensory Integration: It\u27s Not Just for Children
Sensory integration theory and intervention techniques were originally developed by A. Jean Ayres, PhD, OTR, beginning in the late 1960s. Her pioneering work integrated scientific information from neuroscience, psychology, occupational therapy, and human development in an effort to help explain the relationship among experience, brain development, and function. Ayres\u27s theory of sensory integration provides a solid foundation for understanding the impact of sensation on occupational performance across the life span. Although much of the existing work related to sensory integration addresses occupational performance issues in children, some believe the theory and framework to be important across the life span. However, given the original emphasis on pediatrics, occupational therapy practitioners who work in other areas of practice likely do not have exposure to or training in sensory integration and, therefore, may not consider dysfunction in sensory integration as a contributing factor when evaluating clients at different ages or stages of life.
This article makes a case that because humans are sensory beings and sensation is inherent in all occupations, the sensory integration framework is relevant to occupational therapy practice beyond pediatrics. Further, we propose that all occupational therapy practitioners should seek to understand the relevance of the sensory integration framework for the specific clientele with whom they work, regardless of age. We believe that the sensory integration framework can be a useful lens for interpreting behaviors and a guide for implementing strategies to enhance occupational performance in clients across the life span. To this end, some of the sensory-based experiences that persons may encounter across the life span are discussed, and the relevance of the sensory integration framework is proposed. We have chosen to present this information according to a developmental progression to express how dysfunction in sensory integration can be manifested across the life span
Age-dependent Skill Formation and Returns to Education
In this study, we try to connect the economic literature on human capital formation with findings from neurobiology and psychology on early childhood development and self-regulation. Our basic framework for assessing the distribution of agespecific returns to investment in skills is an elaboration of the model of skill formation from Cunha, Heckman et al. (2006) over the life cycle. Our simulation based evidence illustrates the cumulative and synergetic nature of skill formation, the skill multiplier and the shaping role early childhood has for human capital formation, growth and inequality. --Intelligence,self-regulation,human capital,returns to education,life span
Expanding the Life-Span, Life-Space Approach using Critical Race Theory and Intersectionality
Super’s (1980, 1996) life-span, life-space approach of career development has had a major influence on the field of career counseling by shifting the focus beyond a ‘singular point of entry’ into to careers to one multiple transition points and trajectories. While Super’s body of theoretical and empirical contributions to the field of career development are vast, the theory does not adequately address the experiences of Black youth. This article focuses on both theory and praxis by discussing the life-span, life-space approach in the context of career development of Black youth. We describe how critical race theory and intersectionality can be used as key organizing principles in an expanded framework along with Super’s life-span, life-space approach to guide practices in college and career counseling. We end with a discussion of the implications for practice
Kinship
Kinship is a term used broadly in the social sciences, particularly in anthropology, to mean the web of social relationships that make up families. It is a useful framework for thinking about changes over the life span because people’s roles within their families and social networks change as they age and as the social, political, and economic contexts in which they live shift. There are three main concepts that help to explain the importance of kinship across the life span: Kinship is created through practice, kinship is processual, and kinship is inherently flexible. This entry provides a brief history of kinship studies, explores each of these three concepts, explains how they are relevant to understanding the life-span perspective, and provides illustrative examples
Habitability of Super-Earth Planets around Main-Sequence Stars including Red Giant Branch Evolution: Models based on the Integrated System Approach
In a previous study published in Astrobiology, we focused on the evolution of
habitability of a 10 M_E super-Earth planet orbiting a star akin to the Sun.
This study was based on a concept of planetary habitability in accordance to
the integrated system approach that describes the photosynthetic biomass
production taking into account a variety of climatological, biogeochemical, and
geodynamical processes. In the present study, we pursue a significant
augmentation of our previous work by considering stars with zero-age main
sequence masses between 0.5 and 2.0 M_sun with special emphasis on models of
0.8, 0.9, 1.2 and 1.5 M_sun. Our models of habitability consider again
geodynamical processes during the main-sequence stage of these stars as well as
during their red giant branch evolution. Pertaining to the different types of
stars, we identify so-called photosynthesis-sustaining habitable zones (pHZ)
determined by the limits of biological productivity on the planetary surface.
We obtain various sets of solutions consistent with the principal possibility
of life. Considering that stars of relatively high masses depart from the
main-sequence much earlier than low-mass stars, it is found that the biospheric
life-span of super-Earth planets of stars with masses above approximately 1.5
M_sun is always limited by the increase in stellar luminosity. However, for
stars with masses below 0.9 M_sun, the life-span of super-Earths is solely
determined by the geodynamic time-scale. For central star masses between 0.9
and 1.5 M_sun, the possibility of life in the framework of our models depends
on the relative continental area of the super-Earth planet.Comment: 25 pages, 6 figures, 2 tables; submitted to: International Journal of
Astrobiolog
Towards economic sustainability through adaptable buildings
The existing building stock in most countries does not meet the parameters of economic, social and
environmental sustainability. Physical, functional, technological, economical, social and legal obsolescence
are the principal factors driving the decommissioning, refurbishment, alteration and/or adaptation of a
building. In the UK the Government promotes optimum use of the existing building stock through mixed use
in urban centers and encourages conversion of redundant office and retail space into leisure, service and/or
residential uses rather than demolition and renewal. There is therefore a growing need to design new
buildings that are adaptable and flexible over their life span whilst at the same time improving user
satisfaction. A constraint to the implementation of a policy of life span adaptability is the difficulty of
understanding the economic considerations over long time scales. This paper investigates the issues
surrounding the economics of the life span of adaptable buildings, and establishes a conceptual framework
for their economic sustainability.
The investigation is based on a case study of how the uses and function of the built environment and its
supporting infrastructure have changed over a period of 100 years undertaken within a semi-rural Borough in
England, UK. This case study includes a trend analysis identifying the life spans (of buildings), the evolving
planning policies and associated social and cultural issues. A conceptual framework is developed and the
economic impacts of the changes are evaluated through Whole Life Analysis. The validity and reliability of
proposed framework is yet to be tested
Towards economic sustainability through adaptable buildings
The existing building stock in most countries does not meet the parameters of economic, social and environmental sustainability. Physical, functional, technological, economical, social and legal obsolescence
are the principal factors driving the decommissioning, refurbishment, alteration and/or adaptation of a
building. In the UK the Government promotes optimum use of the existing building stock through mixed use
in urban centers and encourages conversion of redundant office and retail space into leisure, service and/or
residential uses rather than demolition and renewal. There is therefore a growing need to design new
buildings that are adaptable and flexible over their life span whilst at the same time improving user
satisfaction. A constraint to the implementation of a policy of life span adaptability is the difficulty of
understanding the economic considerations over long time scales. This paper investigates the issues
surrounding the economics of the life span of adaptable buildings, and establishes a conceptual framework
for their economic sustainability.
The investigation is based on a case study of how the uses and function of the built environment and its
supporting infrastructure have changed over a period of 100 years undertaken within a semi-rural Borough in
England, UK. This case study includes a trend analysis identifying the life spans (of buildings), the evolving
planning policies and associated social and cultural issues. A conceptual framework is developed and the
economic impacts of the changes are evaluated through Whole Life Analysis. The validity and reliability of
proposed framework is yet to be tested
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