World population in 2050: assessing the projections

This paper will review some population projections for the United States, the world, and selected major regions. The total population size, the youth dependency ratio, the elderly dependency ratio, and the total dependency ratio will receive most attention. The underlying assumptions regarding fertility, mortality, and migration will be reviewed. Projections from different sources will be compared where possible.Demography ; Economic conditions

Constant global population with demographic heterogeneity

To understand better a possible future constant global population that is demographically heterogeneous, this paper analyzes several models. Classical theory of stationary populations generally fails to apply. However, if constant global population size P(global) is the sum of all country population sizes, and if constant global annual number of births B(global) is the sum of the annual number of births of all countries, and if constant global life expectancy at birth e(global) is the population-weighted mean of the life expectancy at birth of all countries, then B(global) x e(global) always exceeds P(global) unless all countries have the same life expectancy at birth.average age, Cauchy-Schwarz inequality, constant population, heterogeneity, life expectancy, migration, pensions, population projection, stationary population, zero population growth

Life expectancy is the death-weighted average of the reciprocal of the survival-specific force of mortality

The hazard of mortality is usually presented as a function of age, but can be defined as a function of the fraction of survivors. This definition enables us to derive new relationships for life expectancy. Specifically, in a life-table population with a positive age-specific force of mortality at all ages, the expectation of life at age x is the average of the reciprocal of the survival-specific force of mortality at ages after x, weighted by life-table deaths at each age after x, as shown in (6). Equivalently, the expectation of life when the surviving fraction in the life table is s is the average of the reciprocal of the survival-specific force of mortality over surviving proportions less than s, weighted by life-table deaths at surviving proportions less than s, as shown in (8). Application of these concepts to the 2004 life tables of the United States population and eight subpopulations shows that usually the younger the age at which survival falls to half (the median life length), the longer the life expectancy at that age, contrary to what would be expected from a negative exponential life table.age-structured population, force of mortality, Jensen´s inequality, life expectancy, life table, longevity, negative exponential distribution, survival, USA

Life expectancy

We give simple upper and lower bounds on life expectancy. In a life-table population, if e(0) is the life expectancy at birth, M is the median length of life, and e(M) is the expected remaining life at age M, then (M+e(M))/2≤e(0)≤M+e(M)/2. In general, for any age x, if e(x) is the expected remaining life at age x, and ℓ(x) is the fraction of a cohort surviving to age x at least, then (x+e(x))≤l(x)≤e(0)≤x+l(x)∙e(x). For any two ages 0≤w≤x≤ω, (x-w+e(x))∙ℓ(x)/ℓ(w)≤e(w)≤x-w+e(x)∙ℓ(x)/ℓ(w) . These inequalities give bounds on e(0) without detailed knowledge of the course of mortality prior to age x, provided ℓ(x) can be estimated. Such bounds could be useful for estimating life expectancy where the input of eggs or neonates can be estimated but mortality cannot be observed before late juvenile or early adult ages.inequalities, life expectancy, life table, stationary population

Safety and patient satisfaction of abobotulinumtoxinA for aesthetic use. A systematic review

A systematic review of the published literature (from January 2000 to January 2016) to ascertain the safety of, and patient satisfaction with, the aesthetic use of abobotulinumtoxinA was conducted. In addition to the licensed indications, other special populations were considered for discussion. The potential impact of neutralizing antibodies and systemic toxicity were also addressed. A total of 364 papers were screened and 86 were found to be relevant to the population, intervention(s), and outcomes stipulated in the protocol. The safety and patient satisfaction data from these publications are discussed in this review

Can egalitarianism survive internationalization?

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A gap analysis of confined field trial application forms for genetically modified crops in East Africa: evaluating the potential for harmonization

"The regulatory approval of genetically modified crops in the field initially requires small, restricted experimental trials known as confined field trials. These small scale experiments provide researchers with important information on environmental interactions and agronomic performance of the crop in a safe and contained manner. To authorize confined field trials regulatory review is required, with formats for obtaining relevant information differing from country to country. In this paper, a Gap Analysis is used to identify informational gaps and potential for harmonization of confined field trial application processes in three East African countries - Tanzania, Kenya, and Uganda. The basic principle behind gap analysis is a comparison of the status quo to an ideal with the identification of the differences or gaps and the difficulty involved in removing the gaps. The resulting similarity of the application forms provides a potential basis for harmonization of confined field trial application processes between countries leading to potential efficiency gains." Authors' abstractGenetically modified crops, Gap analysis, Confined field trials, biotechnology,

Food safety and GM crops implications for developing-country research

"In the developing world the approval and cultivation of genetically modified (GM) crops is largely limited to the commercial production of insect-resistant cotton in Argentina, China, India, Mexico, and South Africa.... Approvals of GM crops used for food or feed lag far behind cotton... This gap in approvals is unfortunate, because crop biotechnology, appropriately applied, has the potential to address key production constraints affecting resource-poor farmers. Currently, important public- and private-sector research is underway to help meet the productivity needs of these farmers." from TextFood safety ,food security ,Public health ,