Do carbonate karst terrains affect the global carbon cycle?

Carbonate minerals comprise the largest reservoir of carbon in the earth’s lithosphere, but they are generally assumed to have no net impact on the global carbon cycle if rapid dissolution and precipitation reactions represent equal sources and sinks of atmospheric carbon. Observations of both terrestrial and marine carbonate systems indicate that carbonate minerals may simultaneously dissolve and precipitate within different portions of individual hydrologic systems. In all cases reported here, the dissolution and precipitation reactions are related to primary production, which fixes atmospheric CO2 as organic carbon, and the subsequent remineralization in watersheds of the organic carbon to dissolved CO2. Deposition of carbonate minerals in the ocean represents a flux of CO2 to the atmosphere. The dissolution of oceanic carbonate minerals can act either as a sink for atmospheric CO2 if dissolved by carbonic acid, or as a source of CO2 if dissolved through sulfide oxidation at the freshwater-saltwater boundary. Since dissolution and precipitation of carbonate minerals depend on ecological processes, changes in these processes due to shifts in rainfall patterns, earth surface temperatures, and sea level should also alter the potential magnitudes of sources and sinks for atmospheric CO2 from carbonate terrains, providing feedbacks to the global carbon cycle that differ from modern feedbacks.Keywords: Global carbon cycle, carbonate terrains, organic carbon fixation, remineralization, carbonate mineral dissolution, carbonate mineral precipitation.DOI: 10.3986/ac.v42i2-3.66

Does Group Size Matter? The Impact of Reciprocity on Giving in Local Faith Communities

We compare and contrast how group size affects the internal structure & relational dynamics of religious communities, ranging from small religious congregations to megachurches (in American society). Classic anthropological economic and evolutionary theory holds that reciprocity, particularly altruistic generalized reciprocity, is most likely to strongly influence small groups, especially kinship-based groups. In the case of non-kin groups, studies of behavior mimicking kin altruism have found that all forms of reciprocity, including extreme giving and high-cost behaviors, are most likely to be found in small social groups with tight bonds, particularly those with shared religious beliefs. In the case of larger groups and individuals who are less tightly bound, a different set of factors may be associated with giving and other forms of group interaction. Distribution and redistribution of resources through a mediator, leader or bureaucracy is often more typical of large-scale groups with less direct contact between giver and receiver. How does this dynamic apply to modern religious groups, such as megachurches? In this paper, we propose a conceptual framework for analyzing religious communities, ranging from small-scale and larger-scale churches. Based on theoretical concepts drawn from both Anthropology and Sociology, we indicate that as the social group size increases, the nature of giving, broadly defined, is altered, becoming less direct and less kin-like, and more outwardly focused. By contrast, smaller groups are more likely to focus on interior, direct, reciprocal giving and kin-like altruism on an ongoing basis. Because giving is important to individual happiness as well as to religious community identity, what lessons are there to be learned about best practices in how religious communities organize giving

Shared reading of children's interactive picture books

We report on a study of children and parents shared reading of interactive printed books. We investigated the differences between books with interactive features and books with expressive typography in order to evaluate which features within a book encouraged interaction between the reading participants and the book. 11 parent and child groups took part in the study that involved three observed reading sessions. From our observations we offer suggestions for the development of books and eBooks to encourage shared reading practices

New insights into atmospherically relevant reaction systems using direct analysis in real-time mass spectrometry (DART-MS)

The application of direct analysis in real-time mass spectrometry (DART-MS), which is finding increasing use in atmospheric chemistry, to two different laboratory model systems for airborne particles is investigated: (1) submicron C3–C7 dicarboxylic acid (diacid) particles reacted with gas-phase trimethylamine (TMA) or butylamine (BA) and (2) secondary organic aerosol (SOA) particles from the ozonolysis of α-cedrene. The diacid particles exhibit a clear odd–even pattern in their chemical reactivity toward TMA and BA, with the odd-carbon diacid particles being substantially more reactive than even ones. The ratio of base to diacid in reacted particles, determined using known diacid–base mixtures, was compared to that measured by high-resolution time-of-flight aerosol mass spectrometry (HR-ToF-AMS), which vaporizes the whole particle. Results show that DART-MS probes  ∼  30 nm of the surface layer, consistent with other studies on different systems. For α-cedrene SOA particles, it is shown that varying the temperature of the particle stream as it enters the DART-MS ionization region can distinguish between specific components with the same molecular mass but different vapor pressures. These results demonstrate the utility of DART-MS for (1) examining reactivity of heterogeneous model systems for atmospheric particles and (2) probing components of SOA particles based on volatility