Dietary and Physiological Contributions to the Relationship between Diet, Bone Collagen, and Structural Carbonate δ13C Values

Numerous models have been proposed to explain and predict the relationship between diet, bone collagen, and structural carbonate δ13C values. Within these models, many internal and external factors are implicated in generating the observed variation in δ13C values, such as trophic level, dietary protein source, digestive physiology, tissue growth and remodeling, and post-mortem chemical alteration of bone collagen and bone mineral. The current understanding of the relationship between the isotopic chemistry of bone and diet hinges on the observation that bone collagen and structural carbonate fractionate differentially from diet due to underlying metabolic differences. The stable carbon isotopic composition of bone collagen is shown to strongly reflect the isotopic composition of dietary protein. In contrast, the stable carbon isotopic composition of structural carbonate within bone mineral is representative of the isotopic composition of total diet. The spacing between the δ13C values of bone collagen and structural carbonate is often used as a measure for understanding variation in the isotopic composition of dietary protein relative to total diet. However, the complexity of the diet-tissue relationship often provides limitations and challenges to paleodietary reconstruction using stable isotopic analysis. This paper explores some of the dietary and physiological factors producing and affecting the relationship between diet, bone collagen, and structural carbonate δ13C values

Interpreting Stable Carbon and Nitrogen Isotope Ratios in Archaeological Remains: An Overview of the Processes Influencing the δ13C and δ15N Values of Type I Collagen

The application of isotopic ratio mass spectrometry to archaeological science has produced many important contributions to the study and understanding of ancient human and animal populations. Paleodietary reconstruction through the analysis of stable isotope ratios in skeletal, dental, and soft tissue remains presents another avenue for interpreting the past. The methodology employed to obtain isotopic data from archaeological remains directly influences the types of questions that can be addressed and the interpretation of the data. Furthermore, there are fundamental idiosyncrasies of archaeological specimens and their ante- and post-mortem environments that may influence the results of an isotopic study. This paper explores the ways in which the stable isotopic signatures of carbon and nitrogen in type I collagen in archaeological bones and teeth are formed, modified, or destroyed throughout life and in the post-depositional environment. For a comprehensive review of the methodological and interpretive implications of paleodietary reconstruction using stable isotopic analysis, see Ambrose (1993)

Geoscience after IT: Part J. Human requirements that shape the evolving geoscience information system

The geoscience record is constrained by the limitations of human thought and of the technology for handling information. IT can lead us away from the tyranny of older technology, but to find the right path, we need to understand our own limitations. Language, images, data and mathematical models, are tools for expressing and recording our ideas. Backed by intuition, they enable us to think in various modes, to build knowledge from information and create models as artificial views of a real world. Markup languages may accommodate more flexible and better connected records, and the object-oriented approach may help to match IT more closely to our thought processes

Tobacco retailer density surrounding schools and youth smoking behaviour: a multi-level analysis

<p>Abstract</p> <p>Background</p> <p>Youth smoking prevention should be a public health priority. It is not only vital to prevent youth from smoking but also to prevent non-smoking youth from becoming susceptible to smoking. Past research has examined factors associated with youth's susceptibility to become a future smoker, but research has yet to examine tobacco retailer density and susceptibility to smoking among never smokers. The objectives of this study are to examine how tobacco retailer density surrounding schools and social smoking influences are associated with smoking susceptibility among youth of never smokers, and occasional and daily smoking among youth of current smokers.</p> <p>Methods</p> <p>Data were collected in 2005-2006 from grade 9 to 12 students attending 76 secondary schools in Ontario, Canada, as part of the SHAPES-On study. A series of multi-level logistic regression analyses were performed to understand how student- and school-level factors are associated with three smoking behaviour outcomes: smoking susceptibility among never smokers, occasional smoking, and daily smoking.</p> <p>Results</p> <p>The number of tobacco retailers surrounding a school was found to be associated with the likelihood of a never smoker being susceptible to future smoking (OR 1.03, 95CI% 1.01, 1.05). We also identified that being surrounded by smoking social influences, specifically family and close friends, can substantially increase the likelihood that never smokers are at risk for future smoking or that youth are already occasional or daily smokers.</p> <p>Conclusions</p> <p>We identified that the number of tobacco retailers surrounding a school was associated with an increased odds of being susceptible to future smoking among male never smokers. Smoking social models surrounding youth also appears to have an important impact on their smoking behaviour regardless of their smoking status. It is important for youth smoking prevention programs to begin early, interrupt youths' susceptibility to future smoking, and focus on subgroups that are at higher risk of smoking. The government should consider the impact of tobacco retailer density on youth smoking behaviour, and be cautious when granting licenses for establishments to sell tobacco products.</p

Cartographic research in EREP programme for small scale mapping

There are no author-identified significant results in this report

The roll-your-own cigarette market in Canada: a cross-sectional exploratory study

<p>Abstract</p> <p>Background</p> <p>Even though the use and prevalence of roll-your-own cigarettes (RYO) has been declining over the past decades, RYO remains important. Given the paucity of research examining RYO use, there is a need to better understand the current and potential future context of RYO use.</p> <p>Methods</p> <p>Data from the 2002 Canadian Tobacco Use Monitoring Survey (CTUMS) were used to examine RYO tobacco use among 23,341 Canadians aged 15 and older. Logistic regression models were conducted to examine factors which differentiate smokers who smoke RYO tobacco all of the time, most of the time or sometimes from smokers who do not smoke RYO tobacco.</p> <p>Results</p> <p>We found that 17% (n = 925,000) of current smokers in Canada reported smoking RYO. When compared to manufactured cigarette (MC) smokers, RYO users were heavier smokers, more addicted to nicotine, and less likely to consider quitting smoking. Lower income smokers were more likely to smoke RYO tobacco compared to smokers with high income. Conversely, smokers who had completed secondary school or university were less likely to smoke RYO tobacco compared to smokers who had not completed secondary school.</p> <p>Conclusion</p> <p>This study demonstrates that RYO tobacco use is not a negligible problem within Canada and provides valuable new insight for developing future tobacco control initiatives for this population of smokers.</p

Cassava thesaurus

This structured vocabulary of terms related to cassava is divided into 2 sections: a categorized listing, giving the main relationships among the terms; and an alphabetical listing, giving the full array of relationships among the descriptors. The thesaurus was developed in order to assist the Cassava Information Center at CIAT in indexing and retrieving the large mass of cassava literature. (Abstracts on Tropical Agriculture

International frontiers in agricultural information services

IDRC personnel. Paper on the role of agricultural information services and information centres, and especially of AGRIS in worldwide information exchange and information dissemination - discusses evolution, activities, and prospects of AGRIS with emphasis on the need for accrued national government support (especially the potential contribution of the USA) and the integrated use of fully compatible data banks; includes bibliographic notes