Anglo-Saxon origins investigated by isotopic analysis of burials from Berinsfield, Oxfordshire, UK

The early fifth century transition from Roman Britain to Anglo-Saxon England is a poorly understood period in British history. Historical narratives describe a brutal conquest by Anglo-Saxon invaders with nearly complete replacement of the indigenous population, but aspects of the archaeological record contradict this interpretation leading to competing hypotheses. Rather than replacement, a smaller group of Germanic immigrants may have settled in England as part of the social, religious, and political turmoil happening in western Europe at this time (Dark, 2000; Henig, 2002; Higham, 1992) or rapid acculturation with little contribution from Germanic immigrants may have occurred in the vacuum of Roman abandonment. As the number of Anglo-Saxon immigrants arriving in Britain is one of the focal issues of this debate, strontium and oxygen isotopic ratios, with their ability to identify immigrants in a burial population, offer a technique to test competing hypotheses. We employ oxygen and strontium isotope ratios in tooth enamel to identify the number of continental immigrants in a sample of 19 individuals from the early Anglo-Saxon cemetery at Wally Corner, Berinsfield in the Upper Thames Valley, Oxfordshire, UK. Local variation in bio-available strontium isotope ratios is established using faunal remains from the site and by sampling soils on geological formations within 8 km of the site. The oxygen isotope results show a homogeneous sample that is slightly enriched when calibrated to local meteoric water. One individual with a significantly depleted value may be a continental immigrant. Three others are strontium outliers. With only 5.3% of the sample originating from Europe, the isotopic data support the hypothesis of acculturation. In addition, the isotopic data shows no temporal patterning, although females show a statistically significant enrichment in the oxygen isotope ratio

Testing a global standard for quantifying species recovery and assessing conservation impact.

Recognizing the imperative to evaluate species recovery and conservation impact, in 2012 the International Union for Conservation of Nature (IUCN) called for development of a "Green List of Species" (now the IUCN Green Status of Species). A draft Green Status framework for assessing species' progress toward recovery, published in 2018, proposed 2 separate but interlinked components: a standardized method (i.e., measurement against benchmarks of species' viability, functionality, and preimpact distribution) to determine current species recovery status (herein species recovery score) and application of that method to estimate past and potential future impacts of conservation based on 4 metrics (conservation legacy, conservation dependence, conservation gain, and recovery potential). We tested the framework with 181 species representing diverse taxa, life histories, biomes, and IUCN Red List categories (extinction risk). Based on the observed distribution of species' recovery scores, we propose the following species recovery categories: fully recovered, slightly depleted, moderately depleted, largely depleted, critically depleted, extinct in the wild, and indeterminate. Fifty-nine percent of tested species were considered largely or critically depleted. Although there was a negative relationship between extinction risk and species recovery score, variation was considerable. Some species in lower risk categories were assessed as farther from recovery than those at higher risk. This emphasizes that species recovery is conceptually different from extinction risk and reinforces the utility of the IUCN Green Status of Species to more fully understand species conservation status. Although extinction risk did not predict conservation legacy, conservation dependence, or conservation gain, it was positively correlated with recovery potential. Only 1.7% of tested species were categorized as zero across all 4 of these conservation impact metrics, indicating that conservation has, or will, play a role in improving or maintaining species status for the vast majority of these species. Based on our results, we devised an updated assessment framework that introduces the option of using a dynamic baseline to assess future impacts of conservation over the short term to avoid misleading results which were generated in a small number of cases, and redefines short term as 10 years to better align with conservation planning. These changes are reflected in the IUCN Green Status of Species Standard

Asparagine in plants

Interest in plant asparagine has rapidly taken off over the past 5 years following the report that acrylamide, a neurotoxin and potential carcinogen, is present in cooked foods, particularly carbohydrate-rich foods such as wheat and potatoes which are subjected to roasting, baking or frying at high temperatures. Subsequent studies showed that acrylamide could be formed in foods by the thermal degradation of free asparagine in the presence of sugars in the Maillard reaction. In this article, our current knowledge of asparagine in plants and in particular its occurrence in cereal seeds and potatoes is reviewed and discussed in relation to acrylamide formation. There is now clear evidence that soluble asparagine accumulates in most if not all plant organs during periods of low rates of protein synthesis and a plentiful supply of reduced nitrogen. The accumulation of asparagine occurs during normal physiological processes such as seed germination and nitrogen transport. However, in addition, stress-induced asparagine accumulation can be caused by mineral deficiencies, drought, salt, toxic metals and pathogen attack. The properties and gene regulation of the enzymes involved in asparagine synthesis and breakdown in plants are discussed in detail