Changes in the distribution of family hours worked since 1950

This paper describes trends in average weekly hours of market work per person and per family in the United States between 1950 and 2005. We disaggregate married couple households by skill level to determine if there is a pattern in the hours of work by wives and husbands conditional on either husband's wages or on husband's educational attainment. The wage measure of skill allows us to compare our findings to those of Juhn and Murphy (1997), who report on trends in family labor using a different data set. The educational measure of skill allows us to construct a longer time series. We find several interesting patterns. The married women with the largest increase in market hours are those with high-skilled husbands. When we compare households with different skill mixes, we also find dramatic differences in the time paths, with higher skill households having the largest increase in average hours over time.Hours of labor

Changes in hours worked since 1950

Changes in hours worked since 1950; This article describes changes in the number of average weekly hours of market work per person in the United States since World War II. Overall, this number has been roughly constant; for various groups, however, it has shifted dramatically from males to females, from older people to younger people, and from single- to married-person households. The article provides a unique look at how the lifetime pattern of work hours has changed since 1950 for different demographic groups. The article also documents several factors that may be related to the changes in hours worked: simultaneous changes in Social Security benefits, fertility rates, and family structure. The data presented are based on those collected by the U.S. Bureau of the Census during the 1950_90 decennial censuses.Labor supply ; Labor market

The making of the South African timeshare industry: spatial structure and development challenges

Research on the accommodation sector attracts only a small fraction of contemporary tourism scholarship relating to sub-Saharan Africa. This paper contributes to this expanding literature on segmentation and the accommodation sector in South Africa. Specifically, it examines the establishment and making of the timeshare industry as a distinctive form of accommodation within the national tourism economy. The timeshare industry in South Africa is the largest and most mature in sub-Saharan Africa and among the most important in the developing world. The analysis uses a longitudinal perspective in order to interpret the emerging spatial organisation and evolving structural issues that impacted upon the development of the timeshare industry in its formative years from 1978 to 2002. The study addresses a knowledge gap around the minimal pursuit of historical research within the existing international literature about timeshare

Tourism and Climate Change: Stakeholder Perceptions of At Risk Tourism Segments in South Africa

The aim is to investigate the perspectives of key South African tourism industry stakeholders surrounding the issue of climate change. Previous research has shown that while the tourism industry in many countries is aware of the significance and potential ramifications of climate change, it is not considered a pressing issue and not the least since the impact of the 2008 global economic crisis. In Africa, with the tourism sector potentially facing major threats from climate change, the need for further research is urgent especially with respect to stakeholder perceptions. The study analyzes the development of national policy towards climate change and tourism and the perceptions of 31 key stakeholders on the segments of the national tourism economy most at risk from climate change. The results show at national government level South Africa is seeking to enact tourism and climate based policies. This said, the degree to which such policies might be implementable must be questioned not only in relation to capacity issues at the scale of local government but by the depth of revealed commitment of stakeholders in terms of making meaningful adjustments to the challenges of climate change because of their perceptions of risk. In particular, the interviewees highlighted their awareness that climate change is responsible for threats to biodiversity as well as assets for coastal and marine tourism. Overall the stakeholders perceived differences in the impacts of climate change for different segments of the tourism economy. Of concern was that stakeholders gainsay the potential impacts of climate change for certain segments which international evidence suggests will most definitely be at risk.&nbsp

The timeshare industry of Africa: a study in tourism geography

Within the broad spectrum of tourism accommodation the timeshare industry is a distinctive segment which has attracted only limited research work. This paper represents a contribution to tourism geography as it investigates the location of timeshare resorts in Africa and comparative position of African destinations in the global timeshare economy. The analysis shows the timeshare resort industry in South Africa is the most significant on the continent and is distinctive in its reliance upon domestic rather than international tourists. In terms of the distribution of resorts the key locational consideration in Africa parallels that found in other parts of the world, namely the positioning of resorts in areas of high natural amenity. In the African context this has meant clustering resorts in coastal beach areas and attractive mountain locations, as well as in the areas which afford opportunities for timeshare consumers to experience the African bush. Finally, of note in South Africa is the growth of large timeshare property developments at casino resorts, a development which parallels the experience of certain timeshare developments in the USA

The Influence of Fatty Acid Ester Alcohol Moiety Molecular Structure on Diesel Combustion and Emissions

At present, biodiesel is primarily comprised of fatty acid methyl esters (FAMEs) obtained by the transesterification of a variety of vegetable oils with methanol. However, transesterification can be carried out with a wide variety of alcohols other than methanol. This paper presents experimental studies carried out on a diesel engine supplied with a range of single-molecule fuels to investigate the effect of fuel molecular structure on combustion and emissions. Eight fatty acid esters that can be produced by transesterification of vegetable oils and animal fats using methanol, ethanol, n-propanol, n-butanol, iso-propanol, iso-butanol, and tert-butanol were investigated. The aim was to ascertain the way in which the structure of the alcohol reactant and the corresponding moiety in the ester molecule affects combustion and emissions. Previously obtained experimental results from a second set of 18 nonoxygenated acyclic hydrocarbons were used to assist the interpretation of the test results from the eight fatty acid esters. The engine tests were carried out at constant injection timing, and they were repeated at constant ignition timing and at constant ignition delay, the latter being achieved through the addition to the various fuels of small quantities of ignition improver (2-ethyl hexyl nitrate). Only small differences in ignition quality of the fatty acid esters were found with variation of the molecular structure of the alcohol moiety. Where present, differences in ignition delay were found to be the main driver of both combustion phasing and emissions production. With the effect of ignition delay isolated, physical properties of the esters, such as thermal degradation prior to vaporization and boiling point, were found to exert an influence on levels of particulate and NOx emissions

Combustion and emissions characteristics of toluene/n-heptane and 1-octene/n-octane binary mixtures in a direct injection compression ignition engine

Successfully designing and making effective of use of the next generation of liquid fuels, which will be derived from a range of biomass and fossil sources, requires an understanding of the interactions between structurally similar and dissimilar fuel components when utilised in current engine technology. Interactions between fuel components can influence the release of energy and production of harmful emissions in compression ignition combustion through determination of the autoignition behavior of the fuel. This paper presents experimental studies carried out in a single-cylinder engine supplied with a range of binary mixture fuels to investigate the effect of fuel component interactions on autoignition in direct injection compression ignition. A range of binary mixtures consisting of toluene and n-heptane and also 1-octene and n-octane were tested so as to observe respectively the effect of an aromatic compound and an alkene on n-alkane combustion and emissions. The engine tests were carried out at constant injection timing and they were repeated at constant ignition timing and at constant ignition delay, the latter being achieved through the addition to the various fuels of small quantities of ignition improver (2-ethylhexyl nitrate). Increasing the presence of toluene in the toluene/n-heptane binary mixtures resulted in an increased ignition delay time and generated a distinct two stage ignition process. An increased level of 1-octene in the binary mixtures of 1-octene/n-octane was also found to increase ignition delay, though to a much lesser extent than toluene in the case of the toluene/n-heptane mixtures. Interactions between the fuel components during the ignition delay period appear important in the case of the toluene/n-heptane mixtures but not those of 1-octene/n-octane. At constant injection and constant ignition timings, the combustion phasing and the level of emissions produced by each binary mixture were primarily driven by the ignition delay time. With ignition delay equalised, an effect of adiabatic flame temperature on NOx production was visible