Showing 11862 items
1 November, 2024 by Connor Bamford, Martin Collins, Philip Hollyman, Richard Phillips
Patagonian toothfish (Dissostichus eleginoides) supports valuable fisheries across the Southern Ocean under the management of the Commission for the Conservation of Antarctic Marine Living Resources. The fishery at South Georgia…1 November, 2024 by Teal Riley
Helium isotopes are unrivalled tracers of the origins of melts in the Earth’s convecting mantle but their role in determining melt contributions from the shallower and rigid lithospheric mantle is…Read more on Systematic behaviour of 3He/4He in Earth’s continental mantle
1 November, 2024 by Geraint Tarling, Melody Clark
Antarctic krill (Euphausia superba Dana) is a keystone species in the Southern Ocean ecosystem, with ecological and commercial significance. However, its vulnerability to climate change requires an urgent investigation of…1 November, 2024 by Andrew Clarke, Lloyd Peck
The embryonic development of marine ectotherms has been shown to be strongly temperature dependent across the world's oceans. However, at the coldest sites, in the polar regions, development is even…1 November, 2024 by Tom Jordan, Teal Riley
The Dufek layered mafic intrusion represents the only exposed, deep-seated, part of the Ferrar Large Igneous Province, which extends >3500 km across Antarctica and into parts of Tasmania and New Zealand.…Read more on Reinvestigating the Dufek Intrusion, through joint gravity and magnetic models
1 November, 2024 by Kevin Hughes
Protection of specific species, generally through the implementation of an associated action plan, is a conservation tool used commonly in areas under national jurisdiction. The Antarctic Treaty area is under…1 November, 2024 by Ella Gilbert, Hua Lu, John King, Michael Haigh, Pierre Dutrieux, Ruth Price, Thomas Caton Harrison, Thomas Bracegirdle
Westerlies prevail at low levels over most of the Southern Ocean. Within about 400 km of Antarctica, the winds reverse direction and become the polar or coastal easterlies. Closer to the…Read more on Advances and next steps in observing and modeling Antarctica’s coastal winds
1 November, 2024 by Peter Convey
Hydrocarbon spillage has long been a concern in Antarctica as it can result in detrimental effects on Antarctic biota and ecosystems. Bioremediation, using microorganisms such as microalgae, represents one of…30 October, 2024 by Hannah Cubaynes, Jaume Forcada, Peter Fretwell
Regular counts of walruses (Odobenus rosmarus) across their pan-Arctic range are necessary to determine accurate population trends and in turn understand how current rapid changes in their habitat, such as…30 October, 2024 by Antony Siahaan
A parameterization of the impact of internal waves on momentum transfer at the sea-ice–ocean interface based on previous work by McPhee has been implemented in a sea-ice model for the…26 October, 2024 by George Day
A species' demographic history gives important context to contemporary population genetics and a possible insight into past responses to climate change; with an individual's genome providing a window into the…Read more on Revealing the Demographic History of the European Nightjar (Caprimulgus europaeus)
21 October, 2024 by Louise Sime
Pleistocene Ice Ages display abrupt Dansgaard–Oeschger (DO) climate oscillations that provide prime examples of Earth System tipping points—abrupt transition that may result in irreversible change. Greenland ice cores provide key…18 October, 2024 by Thomas Bracegirdle
We review how the international modelling community, encompassing integrated assessment models, global and regional Earth system and climate models, and impact models, has worked together over the past few decades…18 October, 2024 by Keith Nicholls
Bottom water formation in the Weddell Sea and mass loss from the Filchner–Ronne Ice Shelf are tightly linked by the supply of Warm Deep Water to the continental shelf. Heavy…17 October, 2024 by Philip Trathan
The Southern Ocean exhibits substantial spatio-temporal variation in biogeochemical processes that shape interactions and productivity across food webs. Stable isotopes in marine predators provide an opportunity to capture such variations,…17 October, 2024 by Ashley Bennison
The current highly pathogenic avian influenza H5N1 panzootic is having substantial impacts on wild birds and marine mammals. Following major and widespread outbreaks in South America, an incursion to Antarctica…16 October, 2024 by Andrew Kavanagh
The high latitude ionospheric evolution of the May 10‐11, 2024, geomagnetic storm is investigated in terms of Total Electron Content and contextualized with Incoherent Scatter Radar and ionosonde observations. Substantial…15 October, 2024 by Peter Convey
We isolated and characterized the community of cultivable fungi associated with marine macroalgae present in the Magellan sub-Antarctic straits and the South Shetland Islands, Maritime Antarctica, and evaluated their production…14 October, 2024 by James Kirkham
Ice shelves regulate the flow of the Antarctic ice sheet toward the ocean and its contribution to sea-level rise. Accurately monitoring the basal and surface melting of ice shelves is…13 October, 2024 by Aidan Hunter
The Arctic Ocean is characterized by substantial seasonal and inter-annual variability, of which the sources and impacts are not yet fully understood. Here, we analyze how much of the variability…10 October, 2024 by Xin Yang
The acidity of sea ice and snow plays a key role in the chemistry of the cryosphere; an important example lies in the photochemical catalytic release of reactive bromine in…Read more on Freezing-induced acidification of sea ice brine
4 October, 2024 by Andrew Fleming, Dominic Hodgson, Peter Fretwell
The Antarctic Peninsula has experienced considerable anthropogenic warming in recent decades. While cryospheric responses are well defined, the responses of moss-dominated terrestrial ecosystems have not been quantified. Analysis of Landsat…Read more on Sustained greening of the Antarctic Peninsula observed from satellites
1 October, 2024 by Andrew Wood
Sexing bird species with monomorphic plumage is generally challenging, and sexual size dimorphism (SSD) is often used to develop morphometric-based sexing tools, e.g., using discriminant functions. Within species, local selection…1 October, 2024 by Lily Bentley, Richard Phillips
Aim: Competition is often proposed to drive niche segregation along multiple axes in speciose communities. Understanding spatial partitioning of foraging areas is particularly important in species that are constrained to…Read more on Habitat preferences of Phoebetria albatrosses in sympatry and allopatry
1 October, 2024 by Adriana Giles, Lloyd Peck, Melody Clark, Nadia Frontier, Simon Morley
There is a dearth of basic life history and physiological data from Southern Ocean species, particularly from benthic vagile predators. This is an important data gap because species inhabiting the…1 October, 2024 by Maximilian Lowe, Robert Larter, Tom Jordan
Bedrock geology from Antarctica remains largely unknown since it is hidden beneath thick ice sheets. Geophysical methods such as gravity and magnetic inverse modelling provide a framework to infer crustal…1 October, 2024 by Dominic Hodgson
Global sea levels during the last interglacial (LIG), 129,000–116,000 years ago, may have reached as much as 5–10 m higher than present. However, the elevation of the LIG highstand varies…Read more on Late Pleistocene sea-level constraints across Antarctica
1 October, 2024 by Clara Manno
The aim of this paper is to characterize the plastic and to study a potential relationship between plastic debris characteristics and the presence of fouling biota in an Antarctic Specially…1 October, 2024 by Maximilian Lowe, Robert Larter, Tom Jordan, Teal Riley
Direct geological information in Antarctica is limited to ice free regions along the coast, high mountain ranges, or isolated nunataks. Therefore, indirect methods are required to reveal subglacial geology and…1 October, 2024 by Caroline Holmes, Paul Holland, Thomas Bracegirdle
The reality of human-induced climate change is unequivocal and exerts an ever-increasing global impact. Access to the latest scientific information on current climate change and projection of future trends is…1 October, 2024 by Richard Horne
The 23–24 April 2023 double-peak (SYM-H intensities of −179 and −233 nT) intense geomagnetic storm was caused by interplanetary magnetic field southward component Bs associated with an interplanetary fast-forward shock-preceded…Read more on The April 2023 SYM‐H = −233 nT Geomagnetic Storm: A Classical Event
1 October, 2024 by Peter Convey
In aquatic insects, body size and shape are key traits that may indicate phenotypic plasticity or adaptations to their hydrological landscape. Liodessus chilensis is a small and poorly-known aquatic beetle…1 October, 2024 by Kevin Hughes
Ireland has a rich Antarctic history, with Bransfield, Crozier, Shackleton, Crean and others acting as key Irish individuals in Antarctic exploration. Recognized as a source of Irish national pride, memorials,…1 October, 2024 by Claus-Dieter Hillenbrand
Here, we report the first discovery of Antarctic fossil resin (commonly referred to as amber) within a ~5 cm-thick lignite layer, which constitutes the top part of a ~3 m-long…Read more on First discovery of Antarctic amber [Short note]
1 October, 2024 by Peter Convey
Deception Island is an Antarctic Specially Managed Area that houses historically important sites such as the remains of historical wooden buildings. The impacts of fungal communities on wood in polar…1 October, 2024 by Peter Convey
Regional warming rates experienced in the Antarctic Peninsula since the mid-twentieth century, linked to global climate change, have been amongst the world's fastest. The majority of studies of change in…27 September, 2024
Understanding the genetic and fitness consequences of anthropogenic bottlenecks is crucial for biodiversity conservation. However, studies of bottlenecked populations combining genomic approaches with fitness data are rare. Theory predicts that…27 September, 2024 by Florian Mekhaldi
Extreme solar particle events (ESPEs) are infrequent yet highly potent manifestations of solar activity. These events result in the production of significant amounts of cosmogenic isotopes(CIs): 10Be, 36Cl, and 14C,…26 September, 2024 by Anthony Fox, Ashley Bennison, Dan McKenzie, Elizabeth Holmes, Elaine Fitzcharles, Freya Blockley, George Day, Isabel Stubbs, Jennifer Forster Davidson, Jaume Forcada, Kevin Hughes, Marcia Blyth, Michael Dunn, Norman Ratcliffe, Richard Phillips, Rosamund Hall, Steven Marshall, Simon Morley, Stacey Adlard
Capsule: HPAI H5N1 was documented for the first time in the subantarctic region on Bird Island, South Georgia, resulting in the mortality of Brown Skuas Stercorarius antarcticus, Gentoo Penguins Pygoscelis…26 September, 2024 by David Pearce, Michael Dunn, Peter Convey, Stacey Adlard
The gut microbiomes of Antarctic penguins are important for the fitness of the host birds and their chicks. The compositions of microbial communities in Antarctic penguin guts are strongly associated…24 September, 2024 by Geraint Tarling, Sophie Fielding
The South Georgia region of the Southern Ocean represents the northernmost range edge for Antarctic krill. Of concern is the extent to which rapid warming of surface water temperatures and…24 September, 2024 by Andrew Kavanagh
Long-term reduction (∼20 km) in the height of the ionospheric F2 layer, hmF2, is predicted to result from increased levels of tropospheric greenhouse gases. Sufficiently long sequences of ionospheric data exist…Read more on Calibrating estimates of ionospheric long-term change
24 September, 2024 by Pierre Dutrieux
The Marine Ice Sheet–Ocean Model Intercomparison Project – phase 2 (MISOMIP2) is a natural progression of previous and ongoing model intercomparison exercises that have focused on the simulation of ice-sheet…23 September, 2024 by Peter Convey
Elevation gradients are often used as a proxy for climate change as they allow comparisons of ecological responses over much larger temporal and spatial scales than is possible through experimental…19 September, 2024 by Andrew Meijers, Povl Abrahamsen, Hugh Venables, Alexander Brearley, Michael Meredith, Natasha Lucas
The South Scotia Ridge, in the Atlantic sector of the Southern Ocean, is a key region for water mass modification. It is the location of the Weddell-Scotia Confluence, an area…18 September, 2024 by Lloyd Peck, Nicholas Barrett
Climate change is causing increased coastal freshening in Antarctica, leading to reduced salinity. For Antarctica’s endemic echinoderms, adapted to the stable polar environment, the impact of rapid reductions in coastal…Read more on The impact of acute low salinity stress on Antarctic echinoderms
17 September, 2024 by Dani Jones, Paul Holland
The Amundsen Sea in West Antarctica features rapidly thinning ice shelves, large polynyas, and sizable spring phytoplankton blooms. Although considerable effort has gone into characterizing heat fluxes between the Amundsen…15 September, 2024 by Mervyn Freeman
Substorms are a rapid release of energy that is redistributed throughout the magnetosphere‐ionosphere system, resulting in many observable signals, such as enhancements in the aurora, energetic particle injections, and ground…Read more on On the Association of Substorm Identification Methods
14 September, 2024 by Bryony Freer, Oliver Marsh
Antarctica has an active subglacial hydrological system, with interconnected subglacial lakes fed by subglacial meltwater. Subglacial hydrology can influence basal sliding, inject freshwater into the sub-ice-shelf cavity, and impact sediment…13 September, 2024 by Yohei Takano
This study examines the linkages between the upper-ocean (0–200 m) oxygen (O2) content and stratification in the North Pacific Ocean using four Earth system models (ESMs), an ocean hindcast simulation, and…10 September, 2024
The gut microbiota-immune-brain axis is a feedback network which influences diverse physiological processes and plays a pivotal role in overall health and wellbeing. Although research in humans and laboratory mice…9 September, 2024 by Richard Phillips
Estimates of movement costs are essential for understanding energetic and life-history trade-offs. Although overall dynamic body acceleration (ODBA) derived from accelerometer data is widely used as a proxy for energy…Read more on Dynamic soaring decouples dynamic body acceleration and energetics in albatrosses
7 September, 2024 by Sophie Fielding
Classification of zooplankton to species with broadband echosounder data could increase the taxonomic resolution of acoustic surveys and reduce the dependence on net and trawl samples for ‘ground truthing’. Supervised…5 September, 2024 by Andrew Clelland, Gareth Marshall
Boreal and Arctic regions have warmed up to four times quicker than the rest of the planet since the 1970s. As a result, boreal and tundra ecosystems are experiencing more…5 September, 2024 by Carl Robinson, Keith Nicholls, Tom Jordan
As a part of the project "Melting at Thwaites grounding zone and its control on sea level" (MELT), we developed a compact 750-MHz ice-penetrating radar for phase-sensitive measurements to infer…Read more on An UWB UHF Ice-Penetreating Radar for the Thwaites Melt Project
4 September, 2024 by Katrin Linse
Confined by the Mid-Atlantic Ridge and the European continental shelf, the deep-sea acorn barnacle Bathylasma hirsutum (Hoek, 1883) lives in the northeast Atlantic deep sea where it has been frequently…4 September, 2024 by Ashley Bennison
Density-dependent competition for food influences the foraging behaviour and demography of colonial animals, but how this influence varies across a species’ latitudinal range is poorly understood. Here we used satellite…3 September, 2024 by Ashley Bennison, Elaine Fitzcharles, Freya Blockley, Marcia Blyth, Rosamund Hall
Until recent events, the Antarctic was the only major geographical region in which high pathogenicity avian influenza virus (HPAIV) had never previously been detected. Here we report on the detection…3 September, 2024 by Huw Griffiths, Rowan Whittle
The benthic community around Antarctica is diverse and highly endemic. These cold-adapted species are under threat from local and global drivers, including warming, acidification and changes to the cryosphere. In…1 September, 2024 by Peter Convey
Marine birds and pinnipeds which come to land to breed, rest and moult are widely known to fertilize adjacent terrestrial ecosystems, with cascading effects on vegetation and other trophic levels.…Read more on The impact of marine vertebrates on polar terrestrial invertebrate communities
1 September, 2024 by Peter Convey
While long-range transport is believed to be the primary source of mercury (Hg) in Antarctica, it is known that seabirds transport organic matter, nutrients, and contaminants from the sea to…Read more on Ornithogenic mercury input to soils of Admiralty Bay, King George Island, Antarctica
1 September, 2024 by Andrew Clarke, Lloyd Peck, Melody Clark
The affect of temperature on tissue protein synthesis rates has been reported in temperate and tropical, but not Antarctic fishes. Previous studies have generally demonstrated low growth rates in Antarctic…1 September, 2024 by Xu Zhang
Terrestrial vegetation is a crucial component of the Earth system, and its changes not only represent one of the most distinct aspects of climate change but also exert significant feedback…Read more on Progress of vegetation modelling and future research prospects
1 September, 2024 by Steve Colwell
The Year of Polar Prediction in the Southern Hemisphere (YOPP-SH) held seven Targeted Observing Periods (TOPs) during the 2022 austral winter to enhance atmospheric predictability over the Southern Ocean and…1 September, 2024 by Andrew Kavanagh, Ingrid Cnossen
Increasing carbon dioxide concentrations in the mesosphere and lower thermosphere are increasing radiative cooling in the upper atmosphere, leading to thermospheric contraction and decreased neutral mass densities at fixed altitudes.…Read more on Future Climate Change in the Thermosphere Under Varying Solar Activity Conditions
30 August, 2024 by Yohei Takano
Since their advent over 2 decades ago, autonomous Argo floats have revolutionized the field of oceanography, and, more recently, the addition of biogeochemical and biological sensors to these floats has…28 August, 2024 by Andrew Kavanagh
Cold plasma of ionospheric origin has recently been found to be a much larger contributor to the magnetosphere of Earth than expected. Numerous competing mechanisms have been postulated to drive…Read more on Earth’s ambipolar electrostatic field and its role in ion escape to space
26 August, 2024 by Andrew Orr, Gareth Marshall, Nadine Johnston, Ryan Williams
While climate models broadly agree on the changes expected to occur over the Arctic with global warming on a pan-Arctic scale (i.e. polar amplification, sea ice loss, and increased precipitation),…26 August, 2024 by Peter Convey
The use of yeasts has been explored as an efficient alternative to fungicide application in the treatment and prevention of post-harvest fruit deterioration. Here, we evaluated the biocontrol abilities of…19 August, 2024 by Claus-Dieter Hillenbrand
Knowledge of the behaviour of marine-based ice sheets during times of climatic warming, such as the last deglaciation, provides important information to understand how ice sheets respond to external forcing.…19 August, 2024 by Chester Sands, Peter Convey
Accurate knowledge of geographic ranges of species is essential for effective conservation management. Species with large distributions and good connectivity are presumed to be resilient to adverse localised/regional conditions, whereas…15 August, 2024 by Paul Holland
A crucial factor influencing the mass balance of the West Antarctic Ice Sheet is the Amundsen Sea Low (ASL), a climatological low-pressure region situated off the West Antarctic coast. However,…15 August, 2024 by Gareth Chisham
The aurora and associated high energy particles and currents pose a space weather hazard to communication networks and ground-based infrastructure. Forecasting the location of the auroral oval forms an integral…15 August, 2024 by Claus-Dieter Hillenbrand
With the onset of anthropogenic climate change, it is vital that we understand climate sensitivity and rates of change during periods of warming in the Earth's past to properly inform…14 August, 2024
Polar offshore environments are considered the last pristine soundscapes, but accelerating climate change and increasing human activity threaten their integrity. In order to assess the acoustic state of polar oceans,…7 August, 2024 by Clara Manno, Florence Atherden
Southern Ocean zooplankton provide globally significant ecosystem services through their role in carbon sequestration, nutrient cycling and food webs. However, the remote and extreme nature of the Southern Ocean creates…Read more on Sediment trap illustrates taxon-specific seasonal signals in Southern Ocean zooplankton
7 August, 2024 by Martin Rogers
Mapping sea ice in the Arctic is essential for maritime navigation, and growing vessel traffic highlights the necessity of the timeliness and accuracy of sea ice charts. In addition, with…6 August, 2024 by Christopher Auckland, Povl Abrahamsen, Michael Meredith
The Antarctic Bottom Water (AABW) exported from the Weddell Sea has experienced warming and contraction in the past 30 yrs. Superposed on this decadal trend is substantial annual and interannual…6 August, 2024 by Joanne Johnson, Peter Convey, Peter Fretwell
Terrestrial vegetation communities across Antarctica are characteristically sparse, presenting a challenge for mapping their occurrence using remote sensing at the continent scale. At present there is no continent-wide baseline record…Read more on A satellite-derived baseline of photosynthetic life across Antarctica
5 August, 2024
Inbreeding, the mating of individuals that are related through common ancestry, is of central importance in evolutionary and conservation biology due to its impacts on individual fitness and population dynamics.…5 August, 2024 by Diana Vladimirova, Dieter Tetzner, Ivo Strawson, Jack Humby, Liz Thomas, Thomas Bauska
Biomass burning plays an important role in climate-forcing and atmospheric chemistry. The drivers of fire activity over the past two centuries, however, are hotly debated and fueled by poor constraints…2 August, 2024 by Xu Zhang
Despite extensive investigation, the nature and causes of the Mid-Pleistocene Transition remain enigmatic. In this work, we assess its linkage to asynchronous development of bipolar ice sheets by synthesizing Pleistocene…Read more on Mid-Pleistocene climate transition triggered by Antarctic Ice Sheet growth
2 August, 2024 by Hugh Venables
Scarcity of iron and manganese limits the efficiency of the biological carbon pump over large areas of the Southern Ocean. The importance of hydrothermal vents as a source of these…Read more on Pathways and timescales of Southern Ocean hydrothermal iron and manganese transport
1 August, 2024 by Peter Fretwell
Predictions of the future emperor penguins population, linked to anthropogenic climate change, are stark. Current models suggest that if CO2 emissions continue to rise at present rates, almost all colonies…Read more on Four unreported emperor penguin colonies discovered by satellite
1 August, 2024 by Peter Convey
We studied the culturable fungal community recovered from deep marine sediments in the maritime Antarctic, and assessed their capabilities to produce exoenzymes, emulsifiers and metabolites with phytotoxic activity. Sixty-eight Ascomycota…1 August, 2024 by Amanda Burson, Cecilia Liszka, Clara Manno, Povl Abrahamsen, Geraint Tarling, Kate Hendry, Natasha Lucas, Sally Thorpe
Large icebergs (>20 km long) are responsible for most of the freshwater discharged into the Southern Ocean. We report on in situ and satellite observations made during the break-up phase around…1 August, 2024 by Markus Frey
Novel observations of aerosol and clouds by means of ground-based remote sensing have been performed in Antarctica over the Ekström ice shelf on the coast of Dronning Maud Land at…1 August, 2024 by Richard Phillips
Seabirds are amongst the most threatened taxa in the world, often due to incidental mortality (bycatch) in fisheries. Hundreds of thousands are thought to be killed worldwide in gillnets and…Read more on Incidental mortality of seabirds in trawl fisheries: A global review
31 July, 2024 by Hugo Rodrigues Guimaro
The participation of a diverse –in terms of geography, discipline and gender– group of Early Career Researchers (ECRs) in the peer review process can help alleviate the workload of senior…31 July, 2024 by Kelly Hogan, Peter Davis, Robert Larter
Knowledge gaps about how the ocean melts Antarctica’s ice shelves, borne from a lack of observations, lead to large uncertainties in sea level predictions. Using high-resolution maps of the underside…28 July, 2024 by Anna Jones, Evelyn Workman, Katrin Linse
Sea-air methane flux was measured directly by the eddy-covariance method across approximately 60,000 km of Arctic and Antarctic cruises during a number of summers. The Arctic Ocean (north of 60°N,…24 July, 2024 by Andrew Meijers, Jonathan Rosser
The Southern Ocean provides dominant contributions to global ocean heat and carbon uptake, which is widely interpreted as resulting from its unique upwelling and circulation. Here we show a large…Read more on Asymmetries in the Southern Ocean contribution to global heat and carbon uptake
22 July, 2024 by Andrew Kavanagh, Gareth Chisham, Mervyn Freeman
A significant increase in the number of anthropogenic objects in Earth orbit has necessitated the development of satellite conjunction assessment and collision avoidance capabilities for new spacecraft. Neutral mass density…Read more on Influences of Space Weather Forecasting Uncertainty on Satellite Conjunction Assessment
22 July, 2024 by Elizabeth Boyse
Marine mammal foraging grounds are popular focal points for marine protected area (MPA) implementation, despite being temporally dynamic, requiring continuous monitoring to infer prey availability and abundance. Marine mammal distributions…19 July, 2024 by Claus-Dieter Hillenbrand, James Smith, Robert Larter
One of Earth’s most fundamental climate shifts – the greenhouse-icehouse transition 34 Ma ago – initiated Antarctic ice-sheet build-up, influencing global climate until today. However, the extent of the ice…Read more on Ice sheet–free West Antarctica during peak early Oligocene glaciation
19 July, 2024 by Michael Meredith
Many glaciers on the Antarctic Peninsula have retreated and accelerated in recent decades. Here we show that there has been a widespread, quasi-synchronous, and sustained increase in grounding line discharge…Read more on Widespread increase in discharge from West Antarctic Peninsula glaciers since 2018
17 July, 2024 by Chester Sands, Peter Convey
The Southern Ocean benthos is remarkably rich and diverse, and managed under a complexity of treaties and conventions, further complicated by geopolitical boundaries. Traditionally, conservation management is largely informed by…17 July, 2024 by Richard Horne
Updated summaries of the August 1972 and March 1989 space weather events have been constructed. The features of these two events are compared to the Carrington 1859 event and a…