Mortality Change, the Uncertainty Effect, and Retirement

We examine the role of declining mortality in explaining the rise of retirement over the course of the 20th century. We construct a model in which individuals make labor/leisure choices over their lifetimes subject to uncertainty about their date of death. In an environment in which mortality is high, an individual who saved up for retirement would face a high risk of dying before he could enjoy his planned leisure. In this case, the optimal plan is for people to work until they die. As mortality falls, however, it becomes optimal to plan, and save for, retirement. We simulate our model using actual changes in the US life table over the last century, and show that this “uncertainty effect” of declining mortality would have more than outweighed the “horizon effect” by which rising life expectancy would have led to later retirement. A calibration exercise, allowing for heterogeneity in tastes and other non-mortality factors influencing retirement, shows that falling mortality plausibly had a quantitatively significant effect on retirement.

Mortality Change, the Uncertainty Effect, and Retirement

We examine the role of changing mortality in explaining the rise of retirement over the course of the 20th century. We construct a model in which individuals make labor/leisure choices over their lifetimes subject to uncertainty about their date of death. In an environment in which mortality is high, an individual who saved up for retirement would face a high risk of dying before he could enjoy his planned leisure. In this case, the optimal plan is for people to work until they die. As mortality falls, however, it becomes optimal to plan, and save for, retirement. We simulate our model using actual changes in the US life table over the last century, and show that this 'uncertainty effect' of declining mortality would have more than outweighed the 'horizon effect' by which rising life expectancy would have led to later retirement. One of our key results is that continuous changes in mortality can lead to discontinuous changes in retirement behavior.

Patent Information Retrieval: Approaching a Method and Analyzing Nanotechnology Patent Collaborations

ArticleThis is the final version of the article. Available from Springer Verlag via the DOI in this record.Many challenges still remain in the processing of explicit technological knowledge documents such as patents. Given the limitations and drawbacks of the existing approaches, this research sets out to develop an improved method for searching patent databases and extracting patent information to increase the efficiency and reliability of nanotechnology patent information retrieval process and to empirically analyse patent collaboration. A tech-mining method was applied and the subsequent analysis was performed using Thomson data analyser software. The findings show that nations such as Korea and Japan are highly collaborative in sharing technological knowledge across academic and corporate organisations within their national boundaries, and China presents, in some cases, a great illustration of effective patent collaboration and co-inventorship. This study also analyses key patent strengths by country, organisation and technology

Speciation of heavy metals in street dust samples from Sakarya I. Organized industrial district using the BCR sequential extraction procedure by ICP-OES

This paper focuses on the concentrations of heavy metals (Cd, Co, Cr, Cu, Mn, Ni, Pb and Zn) in 20 dust samples collected from the streets of the Organized Industrial District in Sakarya, Turkey using sequential extraction procedure were determined by ICP-OES. The three-step BCR sequential extraction procedure was used in order to evaluate mobility, availability and persistence of heavy elements in street dust samples. Three operationally defined fractions isolated using the BCR procedure was: acid extractable, reducible, and oxidizable. The mobility sequence based on the sum of the BCR sequential extraction stages: Cd (82.3%) > Mn (80.0%) > Zn (78.8%) > Cu (70.2%) > Ni (65.9%) > Pb (63.8%) > Cr (47.3%) > Co (32.6%). Validation of the analytical results was checked by analysis of the BCR-701 certified reference material. The concentrations of metals in the street dust samples have been shown a decrease after the each extraction stage. KEY WORDS: Heavy metals, ICP-OES, Organized industrial district, Sequential extraction, Dust, Turkey Bull. Chem. Soc. Ethiop. 2013, 27(2), 205-212.DOI: http://dx.doi.org/10.4314/bcse.v27i2.

Expression of T4 Lysozyme Gene (gene e) in Streptococcus salivarius subsp. Thermophilus

In present study, we aimed to express T4 Lysozyme gene (gene e) in Streptococcus salivarus subsp. thermophilus to create better probiotics for poultry. The Esherichia coli plasmid, Bluescript II SK +/-harboring gene e named pL1, was converted to a new E. coli-Streptococcus sp. shuttle vector (pL2) by cloning and inserting Streptococcal replication origin of pTRW10 vector into pL1. pL2 plasmid isolated from E. coli was introduced into S. salivarius subsp. thermophilus and Lactococcus lactis cells by electro-transformation. The lysozyme enzymes expressing by these bacteria were found to be active on Micrococcus luteus cells and thereby preventing their growth on assay plates. Thermostability of these enzymes from the recombinant bacteria was also found different from each other. The lysozyme expressed by S. salivarius subsp. thermophilus cells seemed to increase its capacity for thermoresistance and was not denaturated at 70°C for 15 min. In contrast, the enzyme expressed by L.lactis and E. coli cells were easily denaturated when exposed to the same temperature treatment