Impact of fly ash content and fly ash transportation distance on embodied greenhouse gas emissions and water consumption in concrete

Background, aim and scope Fly ash, a by-product of coal-fired power stations, is substituted for Portland cement to improve the properties of concrete and reduce the embodied greenhouse gas (GHG) emissions. Much of the world's fly ash is currently disposed of as a waste product. While replacing some Portland cement with fly ash can reduce production costs and the embodied emissions of concrete, the relationship between fly ash content and embodied GHG emissions in concrete has not been quantified. The impact of fly ash content on embodied water is also unknown. Furthermore, it is not known whether a global trade in fly ash for use in concrete is feasible from a carbon balance perspective, or if transport over long distances would eliminate any CO(2) savings. This paper aims to quantify GHG emissions and water embodied in concrete (f'(c)= 32 MPa) as a function of fly ash content and to determine the critical fly ash transportation distance, beyond which use of fly ash in concrete increases embodied GHG emissions

Immigration and HIV/AIDS in the New York Metropolitan Area

Because the HIV pandemic undergoes continual change in its locations and affected populations, it is crucial to study HIV risk behaviors among mobile and immigrant groups within and across borders. The impact of cross-cultural migrations and the importance of studying that impact in terms of demographic characteristics as well as cultural and environmental factors has not received adequate attention in public health research. This collaborative analysis utilizes data from three studies of immigrant groups in New York to describe and compare these factors that provide the context for risk and prevention of HIVAIDS and other health challenges. Data discussed were obtained utilizing multi-method approaches to identify and describe HIV risks among both new and more established immigrant populations within the urban settings of North America, with NYC as a central focus. Demographic and epidemiological data situate the analysis within the larger contexts of US migration and the HIV/AIDS epidemic in NYC. The authors identify risk and protective factors embedded to varying degrees in immigrants’ multiple cultures and sub-cultures. The three populations studied include: 1) new Hispanic immigrants from the Dominican Republic, Mexico and Central America; 2) West Indian (Caribbean) immigrants from Jamaica, Trinidad/Tobago and other anglophone Caribbean nations; and 3) South Asian immigrants from India (Indian Americans). The paper seeks differences and commonalities, focusing on the social, attitudinal and behavioral factors that contribute to increased HIV/AIDS vulnerability among these populations. The data presented also identify some of the attitudes and behaviors of individuals and groups, as well as other facilitators and obstacles to transmission for immigrants as they adapt to new environments. Topics addressed include factors affecting HIV/AIDS vulnerability of immigrant groups, goals and expectations, health and mental heath issues, gender role change, sexual risk, alcohol and other drug use, perception of HIV/AIDS risk and implications for prevention