The Square Kilometre Array (SKA) is a planned large radio interferometer designed to operate over a wide range of frequencies, and with an order of magnitude greater sensitivity and survey speed than any current radio telescope. The SKA will address many important topics in astronomy, ranging from planet formation to distant galaxies. However, in this work, we consider the perspective of the SKA as a facility for studying physics. We review four areas in which the SKA is expected to make major contributions to our understanding of fundamental physics: cosmic dawn and reionisation; gravity and gravitational radiation; cosmology and dark energy; and dark matter and astroparticle physics. These discussions demonstrate that the SKA will be a spectacular physics machine, which will provide many new breakthroughs and novel insights on matter, energy, and spacetime.

Introduction: Emergency Department (ED) Transition Coordinators (TC) have been introduced to many EDs. In Alberta, the EDTC role was designed to evaluate the home needs of senior patients (75 years of age) to enable safe return home after an ED visit, thereby mitigating admissions and return ED visits. The effectiveness of this role at achieving its objectives has received limited evaluation. Methods: TCs assess all ED patients 75 years old, and physicians request TC assessment for patients <75 years. The TC assessment includes completing a Transitional Assessment Referral (TAR) form that collects information on comorbidities, living arrangements, connections to community and homecare services, independence in activities of daily living (ADLs), and referrals, and disposition. Trained research staff extracted data from consecutive TARs for patients presenting during April 2017 into a REDCap database. The proportions of patients seen by TCs who were admitted, had an unplanned return to the ED within the study period, or received a new homecare referral were assessed. Categorical variables are reported as proportions; continuous variables are reported as mean and standard deviation (SD) or median and interquartile range (IQR), as appropriate. Results: In April 2017, there were 9849 visits to the ED; of these, TCs assessed 478 patients during 500 visits. The mean age was 82 (SD=11.2) and 41% were male; 22 patients presented twice during April 2017. Patients had a median of 2 (IQR: 1, 5) co-morbidities and 40 (8%) patients reported falls in the past 90 days (median=1; IQR: 1, 2). Overall, 144 (29%) patients lived in a care facility, while 204 (41%) lived at home; residence was unclear or not documented for 152 (30%). Patients reported being independent in a median of 9/14 (IQR: 3, 13) ADLs. An existing homecare connection or receipt of homecare services was documented for 185 patients (37%). Finally, 59 (12%) visits included a new or updated homecare referral, while 200 (33%) ED visits ended in admission. Conclusion: Elderly patients seen in the ED assessed by EDTCs are complex, and despite being well connected, they frequently need hospitalization. In a small proportion of cases, additional or new home care resources are required prior to ED discharge; however, few patients returned to the same ED during the one month study period. Given the high proportion of patients assessed, further evaluation of outcomes is warranted.

Introduction: Increase in functional decline of older adults after discharge from the emergency department (ED) has been reported; however, evaluations of interventions to mitigate this problem are infrequent. Data collected in the ED on older adults may document functional status, yet their utility for research is unknown. This study aimed to assess the usability of data collected by ED Transition Coordinators (EDTC) during routine assessments for functional decline research. Methods: EDTCs assess all patients 75 years old presenting to the ED and complete a standardized Transitional Assessment Referral (TAR) form that documents patients independence and daily functioning. To measure the utility of these forms for research purposes, trained research staff evaluated the TARs completed in April 2017 by TCs in the University of Alberta Hospital ED by extracting data from the TARs into a purpose-built REDCap database. Researchers selected and assessed for completeness and clarity the following variables unique to the TARs: facility vs. non-facility living, goals of care and personal directive, fall history, falls in the past 90 days, independence in 14 activities of daily living (ADLs)/instrumental activities of daily living (IADLS), community services in place, and homecare referrals for discharged patients. The proportion of TARs with data for each variable and the proportion of forms with unambiguous responses in each section are reported. Results: Overall, 500 forms were analysed; patients were 41% male with a mean age of 82 (SD=11.2). Homecare referrals, facility vs. non-facility living, and independence with 14 ADLs/IADLs were the most frequently documented variables (81%, 78%, and 79%, respectively); however for ADLs/IADLs, 59% of the 79% had one or more missing components. While fall history was reported in 301 forms (60%), only 107/301 (36%) reported the number of falls in the last 90 days. The referral to homecare variable was complete in 217/268 (81%) forms; however, 99% of files were missing data about goals of care, personal directives, and receipt of community services. Conclusion: Although some information on elderly patients is consistently reported, many of the social service/human factors associated with functional decline are not recorded. While data on the TARs may be useful for studying functional decline in the ED, exploring the barriers to form completion may improve adherence thereby increasing their research utility.

Three main types of eye have been defined in trilobites; holochroal, schizochroal and the rare abathochroal. At least in holochroal and schizochroal eyes, the lenses consist of oriented calcitic microcrystallites, the so-called trabecula, which run uninterruptedly throughout the lens from top to bottom. It is argued here that these are primary structures and not diagenetic. Holochroal eyes are commonly accepted to correspond to apposition eyes, which are the most common type of compound eyes in arthropods living today. Schizochroal eyes, present only in phacopine trilobites, are characterised by a doublet lens structure, with an aplanatic interface, correcting spherical aberration of the thick lenses to form a sharp focus for incident rays travelling parallel with the optical axis. This classic model seems to be functional for many phacopines. In these the trabecula are present, though all juxtaposed, forming a solid block. In the lenses of some phacopid species, however, the microcrystallites are separated from each other by gaps. If, during life, these gaps were filled with organic material, as the lens grew from the larval stages, or post-ecdysially, each trabeculum would be isolated from its neighbours by an organic sheath. A simple model is proposed here for the generation of the organic sheath surrounding each trabeculum. If the individual trabecula were isolated from each other, then the possibility of a new kind of visual system exists in these ‘derived’ phacopines. The differences between the refractive indexes inside and outside the trabeculum would ensure that each trabeculum acted as a light-guide, so that the whole ‘lens’ becomes a light guide bundle. This would result in a pixelled visual system, unique in the animal realm, but an archetype for modern technology of data transfer.

The Viséan sequence at East Kirkton was deposited in a shallow lake, set within a richly vegetated landscape formed of volcanic cones a few hundred metres high. There was little volcanic activity, however, while the lake existed, and the many tuff horizons within the sequence were washed in during weathering. The lake may have been generally cool, though of unusual water chemistry, as a result of which the spherulitic East Kirkton Limestone precipitated. At times, however, water temperatures may have risen sharply through localised hot-spring activity; both factors deterred ‘normal’ aquatic life.

The bulk of the preserved biota consists of plants (permineralisations and compressions) and dominantly land-living animals, including the oldest terrestrial tetrapods (amphibians and reptiliomorphs), large terrestrial-aquatic eurypterids, the first harvestman and rare millipedes. All these animals lived close to the lake, in a fire-prone forest dominated by gymnosperms and pteridosperms.

At a late stage in the history of the lake, deposition of spherulitic limestones was replaced by black shales, bearing a ‘standard’ Oil-Shale fish fauna, suggesting that the isolated lake had linked with a larger fish-bearing water body. This is coupled with a shift to a lycopod-dominated flora and may indicate a climatic change to wetter conditions. Finally the lake silted up with tuff, ending an existence of only a few tens of thousands of years.

Newly discovered crustaceans from the Granton ‘shrimp-bed’ (Dinantian, Lower Oil Shale Group) are described: Bairdops elegans, Minicaris sp., Palaemysis, Tealliocaris cf. woodwardi, Pseudogalathea ornatissima, Anthracocaris scotica, Paraparchites cf. okeni, Beyrichiopsis plicata, and Eocypridina cf. aciculata, and new observations on Waterstonella grantonensis are reported. Tealliocaris woodwardi alone is recorded from bed o, a level ca 1 m below the ‘shrimp-bed’. The Granton ‘shrimp-bed’ biota is reviewed—the geological and lithological context of the deposit, the distribution and taphonomy of the biota, its life environment, palaeoecology, the likely causes of mortality, and comparisons are made with contemporaneous shrimp biotas. The nature of this unusual Konservat-Lagerstätte reflects conditions in the sheltered, periodically emergent lagoon which it represents.

Shrimp-like malacostracan crustaceans first appeared in the late Devonian and underwent a substantial adaptive radiation in the Carboniferous. They are rarely found in rocks of fully marine origin but are well represented in sediments laid down in brackish water and marginal marine conditions; such transitional environments provide the exceptional circumstances required for the preservation of unmineralised shrimps. The best examples are in the Dinantian of Scotland, the Namurian of Montana, and the Westphalian of Illinois. It is probable that shrimps were widespread in contemporaneous marine environments, but are not preserved.

Any approach to understanding the physiology of fossil organisms is necessarily indirect. The diversity of crustacean communities, and the nature of associated taxa and trace fossils, are the most useful biotic factors for interpreting the habitat and tolerance of fossil examples.

All known Carboniferous crustacean communities lived in brackish conditions; none is fully marine. Malacostracan assemblages in the Dinantian of Britain show a general trend of increasing diversity with salinity, from a single taxon at Gullane (stratified freshwater lake or brackish lagoon) to ten at Glencartholm (approaching normal marine). Tealliocaris is associated with low salinities. Crangopsis socialis is confined to the brackish water interdistributary bay environment, but Bairdops and Belotelson display a broader environmental tolerance. Crangopsis eskdalensis, Sairocaris, and Perimecturus occur only at Glencartholm, indicating a requirement for a strong marine influence. Those taxa confined to a limited environmental range all occur where a marine influence is pronounced; none occurs solely in areas of lower salinity. While salinity was apparently the dominant influence on distribution, a complex of independently varying environmental factors was involved. The range of habitats colonised early in the Carboniferous indicates that the preserved taxa had already developed advanced osmoregulatory mechanisms.

The Lower Carboniferous of northern Britain is dominated by non-marine sequences which yield fish and crustacean faunas. These are rarely preserved and occur in thin layers. The sedimentology of twelve shrimp-bearing localities is described, in most cases for the first time, to shed light upon the habitats occupied by eumalacostracan crustaceans during their early Carboniferous adaptive radiation. Nearly all these sequences were deposited in coastal delta-plain settings or in interdistributary bays, environments of transitional salinity. The Gullane shrimp bed, however, was laid down in a thermally stratified non-marine lake, and its sole crustacean representative, Tealliocaris, seems to have been generally confined to waters of low salinity. None of the shrimp-beds was deposited in a fully marine environment, though most show evidence of at least some marine influence. Crustacean diversity increases with salinity, and the lack of shrimps in fully marine sediments is largely due to taphonomic factors rather than an environmental control.

The Tealliocaris and Crangopsis previously recorded from Foulden are shown to be Bairdops elegans and Belotelson traquairi, respectively. This locality thus yields the oldest Known Bairdops. The two species are confined to the lower Carboniferous sedimentary basin S of the Southern Uplands massif. Elsewhere, these genera are thought to characterise the nearshore marine fauna. The reciprocal relationship noted between malacostracans and actinopterygians may therefore be a function of fluctuating salinity.

The Foulden Fish Bed was deposited in a semi-permanent brackish water lake on a floodplain between a northerly mountain range and the sea. The lake supported a rich biota mainly of swimming animals (fish and crustaceans) with a benthos of trace fossils only in the earlier and later stages of the lake's development. Xiphosurans are very rare. This biota changed according to the physical conditions of the lake. Salinity, fluctuating according to water level, was a dominant control. Early in the lake's history there was a dominant benthos of euryhaline bivalves; at the same time, large rhizodonts lived in the lake as the top carnivores. Subsequently, crustaceans were the dominant nektobenthos, in a probable brackish-water regime, the rare Bairdops preying on the common Belotelson; there was a limited infauna. Following this, palaeoniscids abound in the middle part of the sequence, perhaps due to a higher water level but crustaceans are absent at this horizon. During the last stages before final silting-up following a mass-mortality episode, biotic diversity reached a maximum with many fishes and crustaceans and some trace fossils, due to optimal salinity conditions.

Comparisons are made with other Carboniferous biotas and with the Jurassic Solnhofen limestone.

Tealliocaris is probably one of the best preserved of all Carboniferous crustaceans. It occurs scattered through the 12 cm thick laminated Gullane ‘shrimp-bed’. The cuticle is exceptionally well preserved and the specimens, which are normally complete, are infilled with fluorapatite. The carapace has an elongate rostrum, a defined frontal area, a median ridge and paired gastric and inner and outer lateral ridges. The eyes are borne on a stout peduncle. The first antenna bears a pair of flagella, the second an antennal scale and long flagellum. The mandible is large and heavily sclerotised with molar and incisor process. The maxillae and anterior thoracopods are poorly preserved. The posterior six thoracopods each have a long segmented endopod and annulated setose exopod. More than half the specimens preserve lamellae which may represent branchial epipods, or floor a brood chamber beneath the carapace on either side of the thorax. The pleopods are biramous. The telson and uropods form a tail fan. In the absence of oostegites Tealliocaris cannot be assigned to the order Mysidacea but its affinities lie close to these Eumalacostraca. Tealliocaris walked on the thoracic endopods, but could also swim using the pleopods and thoracic exopods. The mode of feeding is uncertain. Tealliocaris probably inhabited a brackish lake or lagoon, but its distribution elsewhere suggests that it may have been tolerant of a range of salinities.

Calyptaulax brongniartii (Portlock) from the Caradocian Bardahessiagh Formation, Pomeroy, Northern Ireland is redescribed. Equivalent material from Scottish horizons (Balclatchie and Ardwell groups) is regarded as belonging to separate populations. Campbell's system of notation is used to describe variation in the arrangement and number of lenses in the eye. The most closely related species is C. strasburgensis (Ulrich & Delo) from the Edinburg Limestone of Virginia, U.S.A.