Knowledge of future mortality levels and trends is important for actuarial practice but poses a challenge to actuaries and demographers. The Lee-Carter method, currently used for mortality forecasting, is based on the assumption that the historical evolution of mortality at all age groups is driven by one factor only. This approach cannot capture an additive manner of mortality decline observed...

in the last few decades, iran has experienced sharp fertility decline. studies indicate that women have a major role in childbearing; therefore, their empowerment and autonomy will lead to changes in their fertility behavior. this paper examines the relationship between family power structure and fertility behavior in the tehran city. the data is collected from around 400 women in tehran who ar...

The resource-based cities in Heilongjiang Province occupied a very important position. These cities and regions mostly faced with relative decline dilemma due to natural resources plunged. These directly affect the development of resources city. Therefore, industry transformation of resources city is realizing the sustainable development of regional economy.

the geographical scope of a dynasty and the selection of a capital as the center of its power can be considered as the essential factors in the establishment of a regime and its continuity; this matter seems to be neglected in the political structure of khwarazmshahi dynasty (598-628/1202-1231). the khwarazmshahi which were supposed to change into one of the greatest medieval dynasties led the ...

     Reduction of water resources limits the ability of farmers for food production and subsistence. Nowadays the quick growth of population has been the most important factor in the decline of renewable water. In many parts of Iran, including region of interest, the major factor in water resources decline was land use change, that may  cause to ecological destruction and disruption. Sustainabl...

A new challenge which the world will face in near future is the reduction of water resources regarding to global climate changes. Climate change is one of the phenomena which will threats future of the universe. Iran locates in an arid and semi-arid region and has limited water resources. Based on global and Intergovernmental Panel on Climate Change (IPCC) board database and the statistics of s...

Economic downturns could have long-term impacts on population health if they promote changes in health behaviors, but the evidence for whether people are more or less likely to adopt negative health behaviors in economically challenging times has been mixed. This paper argues that researchers need to draw more careful distinctions amongst different types of recessionary hardships and the mechan...

Evidence for declining populations of both wild and managed bees has raised concern about a potential global pollination crisis. Strategies to mitigate bee loss generally aim to enhance floral resources. However, we do not really know whether loss of preferred floral resources is the key driver of bee decline because accurate assessment of host plant preferences is difficult, particularly for s...