Learn More
At the close of the Fourth International Polar Year, we take stock of the ecological consequences of recent climate change in the Arctic, focusing on effects at population, community, and ecosystem scales. Despite the buffering effect of landscape heterogeneity, Arctic ecosystems and the trophic relationships that structure them have been severely(More)
—Big Data has driven the need for datastores that can scale horizontally leading to the development of many different NoSQL database implementations, each with different persistence and query philosophies. Spatio-temporal data such as location data is one of the largest types of data being collected today. We describe a novel spatio-temporal index structure(More)
Migratory geese accumulate energy and nutrient stores in winter to fly to refuelling spring staging areas before onward migration to breeding areas. Mean ground temperatures at two important Greenland White-fronted Geese wintering sites rose in winter and spring by 1.0–1.3°C during 1973–2007. Greenland White-fronted Geese departed the Wexford winter(More)
Greenland White-fronted Geese wintering in Ireland and Britain stage for 3 weeks in Iceland in spring before migrating onwards to breeding areas in west Greenland. The geese now depart their wintering quarters 12–15 days earlier than in 1973 because they attain necessary fat stores earlier than in previous years. Icelandic temperatures at critical midway(More)
— One of the benefits of a computational grid is the ability to run high-performance applications over distributed resources simply and securely. We demonstrated this benefit with an experiment in which we studied the protein-folding process with the CHARMM molecular simulation package over a grid managed by a grid operating system, Legion. High-performance(More)
Demographic links among fragmented populations are commonly studied as source-sink dynamics, whereby source populations exhibit net recruitment and net emigration, while sinks suffer net mortality but enjoy net immigration. It is commonly assumed that large, persistent aggregations of individuals must be sources, but this ignores the possibility that they(More)
Measures of first-year autumn mortality rates are important parameters for understanding population dynamics, but have been hitherto unavailable for dabbling ducks in Europe, because most ducks are ringed in winter. We used the temporal change in the proportion of juveniles in wing samples from hunters in Finland, Denmark and UK, together with adult(More)
Geese often forage on mid-winter foods that fail to satisfy daily energy needs, but they may do so to acquire other nutrients, such as nitrogen. We tested this hypothesis by evaluating nitrogen budgets, namely the balance of nitrogen income against expenditure, of wintering Lesser White-fronted Geese Anser erythropus feeding at two sites within East(More)
The term ‘short-stopping’ is increasingly used in ecology to describe spatio-temporal changes in occurrence of migratory species. Spurred by the insight that it has been used in a variety of contexts, we reviewed its use in avian ecology. A literature search yielded 59 papers explicitly treating short-stopping in birds, most of them in peer-reviewed(More)