Oyster shells as history books

[FIRST PARAGRAPH] A collaborative project was established in 2002 that has brought together geochemistry and archaeology in order to investigate environmental change and the harvesting strategies of ancient peoples. The objectives of this study are to decipher the life history and environmental information contained in shells of the European oyster, Ostrea edulis, by analyzing geochemical variations along shell growth. This approach provides an independent measure of age and season of death, as well as a record of environmental change in temperature and salinity through the life of the oyster. By understanding the life history and environmental records contained in modern oyster shells, we can analyze shells from archaeological sites to gain an historical perspective of harvesting practices and environmental change in ancient shellfisheries

Resources, outcomes, and funding of public schools

Education

Irreversible proliferation of magnetic moments at cleaved surfaces of the topological Kondo insulator SmB6

The compound SmB$_6$ is the best established realization of a topological Kondo insulator, in which a topological insulator state is obtained through Kondo coherence. Recent studies have found evidence that the surface of SmB$_6$ hosts ferromagnetic domains, creating an intrinsic platform for unidirectional ballistic transport at the domain boundaries. Here, surface-sensitive X-ray absorption (XAS) and bulk-sensitive resonant inelastic X-ray scattering (RIXS) spectra are measured at the Sm N$_{4,5}$-edge, and used to evaluate electronic symmetries, excitations and temperature dependence near the surface of cleaved samples. The XAS data show that the density of large-moment atomic multiplet states on a cleaved surface grows irreversibly over time, to a degree that likely exceeds a related change that has recently been observed in the surface 4f orbital occupation

The use of seasonally resolved temperature data to identify the cause of marine climate change

On the continental shelf of the eastern USA, seasonal variation in water temperature is much lower south of Cape Hatteras than it is to the north as a result of the influence of warm currents, which raise winter temperature. High temperatures north of Cape Hatteras during the Pliocene have been attributed to greater northward penetration of warm currents in the absence of a feature analogous to Cape Hatteras. However, oxygen isotope thermometry using serial ontogenetic samples from scallops reveals a high seasonal temperature range at some horizons, suggesting that overall warming was the consequence of general climate change, with the absence of a ‘Cape Hatteras’ feature allowing greater southward penetration of cold currents, resulting in low winter temperatures at a southerly latitude. Evidence from other taxa indicates that at times seasonal variation in water temperature was quite low and that there was greater northward penetration of warm currents. This may relate to increases in vigour of the Gulf Stream. The study shows how seasonally resolved temperature data can assist identification of the driving forces of marine climate change.British Geological Survey (BUFI S157

Anti-predation strategy, growth rate and extinction amongst Pliocene scallops of the US eastern seaboard

Placopecten, Chesapecten and Carolinapecten are scallop (pectinid bivalve) genera occurring in the Pliocene of the US eastern seaboard. The first, present in the area today, is a smooth, streamlined form, adept at escaping predators by swimming (‘flight’ strategy). The other two, which are extinct, are plicate (‘ribbed’) forms. Plication facilitates a ‘resistance’ strategy towards predators which is benefited by large size and high shell thickness - maximally so if these states are achieved early in life. Oxygen isotope profiles show that early ontogenetic extensional growth in Pliocene Placopecten was at the same moderate rate as in modern Placopecten. By contrast, in Chesapecten it was as fast as in the fastest-growing modern scallop (c. 80 mm/annum), and accompanied by development of an unusually thick shell, while in Carolinapecten it was substantially faster still (<150 mm/annum). Rapid growth in Chesapecten and Carolinapecten was probably enabled by high primary productivity, for which there is evidence from sediment composition and the associated biota. The extinction of Chesapecten and Carolinapecten, and the survival of Placopecten, can be attributed to a decline in primary productivity which prevented a maximally effective ‘resistance’ strategy towards predators but had no deleterious impact on a ‘flight’ strategy.British Geological Survey (BUFI S157

39 Social Justice Books and Movies to Keep Your Brain Warm Over Winter Break!

A hodgepodge of books and movies, some serious, some funny that engage issues of social justice in a variety of ways. If you read or watch one, let us know what you think in the comments! [excerpt

How best to engage users of forensic services in research: literature review and recommendations

Guidance on service user involvement is available to help researchers working with people with mental health problems, but there is currently no comprehensive guidance relating to forensic settings where additional issues arise. This rapid review aims to summarise the currently available information on how best to engage users of forensic mental health services in the research process, and to make appropriate recommendations. Medline and five other databases were searched to May 2016 using relevant keywords and Medical Subject Headings, supplemented by a general Internet search. Eleven peer-reviewed journal papers and 12 reports or web-based documents were identified, the majority containing information derived using a qualitative methodology. Five areas of particular relevance to forensic settings were identified: power relations & vulnerability issues (including ethical treatment; informed consent; attitudes of staff and other service users; support), practical difficulties (including ‘consultation fatigue’; tokenistic inclusion; tensions over security and risk management; access; payment; co-authoring); confidentiality and transparency; language and communication and training issues. Recommendations on engaging service users in forensic mental health research are presented

Selected research findings from rwanda that inform policy themes in Southern Africa

A research paper on findings from Rwanda that could assist policy makers in Southern Africa with food security policies and strategies.Section I of this paper reviews recent events in Rwanda. In section II we identify principal research findings from Rwanda with the objective of helping inform five important food security themes in Southern Africa. Food and agricultural policy foci in Rwanda Rwanda faces tremendous challenges in its food and agricultural sectors. The landlocked country is struggling against high population density (the country is 90% rural) and poor links with seaports to improve the performance of its economy. The Government of Rwanda’s (GOR) main objectives in the agricultural sector have been to increase food self-sufficiency and rural incomes. In the past, the GOR’s means of achieving these goals have been relatively successful. The country has focused on cropping previously unused land, maintaining soil fertility, improving some crop varieties, and trying to stabilize bean and sorghum prices. They also have tried to modestly increase prices paid to farmers for selected food crops while maintaining a buffer stock to attenuate consumer price increases when food supplies contract.United States Agency for International Development (US- AID

Assessing elemental ratios as a paleotemperature proxy in the calcite shells of patelloid limpets

Archaeological shell and fish middens are rich sources of paleoenvironmental proxy data. Patelloid limpet shells are common constituents in archaeological middens found along European, African, and South American coastlines. Paleotemperature reconstructions using oxygen isotope ratios of limpet shells depend on the ability to constrain the oxygen isotope ratio of seawater; therefore, alternative proxies are necessary for coastal localities where this is not possible. The study evaluates whether Mg/Ca, Sr/Ca, Li/Ca, Li/Mg, and Sr/Li ratios are reliable proxies of sea surface temperature (SST) in the calcite layer of shells of the patelloid limpets, Patella vulgata and Nacella deaurata. We compare Mg/Ca, Sr/Ca, Li/Ca, Li/Mg, and Sr/Li ratios to the seasonal variations in contemporaneous δ18Oshell values, which primarily record seasonal changes in SST. Elemental ratios (Mg/Ca, Sr/Ca, Li/Ca, Li/Mg, and Sr/Li) show no significant correlations with reconstructed SST in P. vulgata and N. deaurata shells, nor do they show sinusoidal cycles expected from a SST proxy. In addition, shell δ13C values show no significant ontogenetic trends, suggesting that these limpets exhibit little change in metabolic carbon incorporation into the shell with increasing ontogenetic age. Although shell growth rate exhibits a logarithmic decrease with age based on calculated linear extension rates, growth rate does not correlate with elemental profiles in these limpets. Overall, ele