22 research outputs found
Magnetism, FeS colloids, and Origins of Life
A number of features of living systems: reversible interactions and weak
bonds underlying motor-dynamics; gel-sol transitions; cellular connected
fractal organization; asymmetry in interactions and organization; quantum
coherent phenomena; to name some, can have a natural accounting via
interactions, which we therefore seek to incorporate by expanding the horizons
of `chemistry-only' approaches to the origins of life. It is suggested that the
magnetic 'face' of the minerals from the inorganic world, recognized to have
played a pivotal role in initiating Life, may throw light on some of these
issues. A magnetic environment in the form of rocks in the Hadean Ocean could
have enabled the accretion and therefore an ordered confinement of
super-paramagnetic colloids within a structured phase. A moderate H-field can
help magnetic nano-particles to not only overcome thermal fluctuations but also
harness them. Such controlled dynamics brings in the possibility of accessing
quantum effects, which together with frustrations in magnetic ordering and
hysteresis (a natural mechanism for a primitive memory) could throw light on
the birth of biological information which, as Abel argues, requires a
combination of order and complexity. This scenario gains strength from
observations of scale-free framboidal forms of the greigite mineral, with a
magnetic basis of assembly. And greigite's metabolic potential plays a key role
in the mound scenario of Russell and coworkers-an expansion of which is
suggested for including magnetism.Comment: 42 pages, 5 figures, to be published in A.R. Memorial volume, Ed
Krishnaswami Alladi, Springer 201
Understanding Alkyl Substituent Effects in R-O Bond Dissociation Reactions in Open- and Closed-Shell Systems
The inhibition of tumor cell adhesion on human mesothelial cells (HOMC) by phospholipids in vitro
Multi-proxy studies in palaeolimnology
Multi-proxy studies are becoming increasingly common in palaeolimnology. Eight basic requirements and challenges for a multi-proxy study are outlined in this essay – definition of research questions, leadership, site selection and coring, data storage, chronology, presentation of results, numerical tools, and data interpretation. The nature of proxy data is discussed in terms of physical proxies and biotic proxies. Loss-on-ignition changes and the use of transfer functions are reviewed as examples of problems in the interpretation of data from multi-proxy studies. The importance of pollen analysis and plant macrofossil analysis in multi-proxy studies is emphasised as lake history cannot be interpreted without knowledge of catchment history. Future directions are outlined about how multi-proxy studies can contribute to understanding biotic responses to environmental change
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Sedimentology of lower Pliocene to Upper Pleistocene diamictons from IODP Site U1358, Wilkes Land margin, and implications for East Antarctic Ice Sheet dynamics
AbstractDuring the early Pliocene a dynamic marine-based ice sheet retreated from the Wilkes Land margin with periodic ice advances beyond Last Glacial Maximum position. A change in sand provenance is indicative of a more stable Mertz Glacier system during the Late Pleistocene. East Antarctic Ice Sheet (EAIS) dynamics were evaluated through the analysis of marine diamictons from Integrated Ocean Drilling Program (IODP) site U1358 on the Adélie Land continental shelf. The warmer than present conditions of the early Pliocene coupled with the site's proximity to the landward sloping Wilkes Subglacial Basin provided the rationale for the investigations at this site. Based on visual core descriptions, particle size distributions, and major and trace element ratios, we interpret the origin of lower Pliocene strata by intermittent glaciomarine sedimentation with open-marine conditions and extensive glacial advances to the outer shelf. Heavy mineral analyses show that sand-sized detritus in the lower Pliocene strata was sourced from local intermediate to high-grade metamorphic rocks near Mertz Glacier. In contrast, Pleistocene diamictons exhibit a larger contribution from a prehnite-pumpellyite greenschist facies suggesting supply via iceberg rafting from northern Victoria Land. From this sedimentological evidence, we postulate a shift from a dynamic EAIS margin in the early Pliocene to possible stabilization in the Pleistocene
Developing the national community health assistant strategy in Zambia : a policy analysis
BACKGROUND: In 2010, the Ministry of Health in Zambia developed the National Community Health Assistant strategy, aiming to integrate community health workers (CHWs) into national health plans by creating a new group of workers, called community health assistants (CHAs). The aim of the paper is to analyse the CHA policy development process and the factors that influenced its evolution and content. A policy analysis approach was used to analyse the policy reform process. METHODOLOGY: Data were gathered through review of documents, participant observation and key informant interviews with CHA strategic team members in Lusaka district, and senior officials at the district level in Kapiri Mposhi district where some CHAs have been deployed. RESULTS: The strategy was developed in order to address the human resources for health shortage and the challenges facing the community-based health workforce in Zambia. However, some actors within the strategic team were more influential than others in informing the policy agenda, determining the process, and shaping the content. These actors negotiated with professional/statutory bodies and health unions on the need to develop the new cadre which resulted in compromises that enabled the policy process to move forward. International agencies also indirectly influenced the course as well as the content of the strategy. Some actors classified the process as both insufficiently consultative and rushed. Due to limited consultation, it was suggested that the policy content did not adequately address key policy content issues such as management of staff attrition, general professional development, and progression matters. Analysis of the process also showed that the strategy might create a new group of workers whose mandate is unclear to the existing group of health workers. CONCLUSIONS: This paper highlights the complex nature of policy-making processes for integrating CHWs into the health system. It reiterates the need for recognising the fact that actors' power or position in the political hierarchy may, more than their knowledge and understanding of the issue, play a disproportionate role in shaping the process as well as content of health policy reform