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Impressions of soft-bodied Ediacaran megafossils are common in deep-water slope deposits of the June beds at Sekwi Brook in the Mackenzie Mountains of NW Canada. Two taphonomic assemblages can be recognized. Soles of turbidite beds contain numerous impressions of simple (Aspidella) and tentaculate (Hiemalora, Eoporpita) discs. A specimen of the frond Primocandelabrum is attached to an Aspidella-like holdfast, but most holdfast discs lack any impressions of the leafy fronds to which they were attached, reflecting Fermeuse-style preservation of the basal level of the community. Epifaunal fronds (Beothukis, Charnia, Charniodiscus) and benthic recliners (Fractofusus) were most commonly preserved intrastratally on horizontal parting surfaces within turbidite and contourite beds, reflecting a deep-water example of Nama-style preservation of higher levels in the community. A well-preserved specimen of Namalia significantly extends the known age and environmental range of erniettomorphs into deep-water aphotic settings. Infaunal bilaterian burrows are absent from the June beds despite favorable beds for their preservation. The June beds assemblage is broadly similar in age and environment to deep-water Avalonian assemblages in Newfoundland and England, and like them contains mainly rangeomorph and arboreomorph fossils and apparently lacks dickinsoniomorphs and other clades typical of younger and shallower Ediacaran assemblages. Fossil data presently available imply that the classically deep- and shallow-water taxa of the Ediacara biota had different evolutionary origins and histories, with sessile rangeomorphs and arboreomorphs appearing in deep-water settings approximately 580 million years ago and spreading into shallow-water settings by 555 Ma but dickinsoniomorphs and other iconic clades restricted to shallow-water settings from their first known appearance at 555 Ma until their disappearance prior to the end of the Ediacaran.

New Ediacaran fossil finds at Sekwi Brook occur in lower shoreface to offshore transition beds at the top of the Blueflower Formation, which are the most shallow-water facies and the youngest strata in which Ediacara-type fossils have been described from the Mackenzie Mountains of NW Canada. Newly discovered Ediacaran body fossils include two new tubular genera: Sekwitubulus annulatus new genus new species was a mm-diameter rigid annulated tube that was rooted to the sea bottom by a holdfast; Annulatubus flexuosus n. gen. n. sp. was a cm-diameter, flexible annulated tube. In conjunction with previously described large attachment discs representing the form-genus Aspidella and a single specimen of the dickinsonid Windermeria, these fossils define an assemblage that differs markedly from the rangeomorph-dominated deeper-water and older assemblages lower in the same section at Sekwi Brook. In contrast, trace fossils show little change upwards through the Blueflower Formation, at least in part reflecting their origin by microbial grazers on mats that formed during low-energy periods in both deep- and shallow-water environments. This implies that the stratigraphic succession of Ediacaran fossils in NW Canada and probably globally represents both evolutionary changes with age and the paleoecology of specific depositional settings.

A concordant U-Pb zircon age of 569.6±5.3 Ma from synrift volcanic rocks of the Hamill Group, southeastern Canadian Cordillera, provides the first direct U-Pb geochronologic constraint on timing of latest Neoproterozoic rifting along western Laurentia. This age confirms a previous estimates of 5.75±25 Ma for timing of continental breakup, as derived from the analysis to tectonic subsidence in lower Paleozoic miogeoclinal strata of the North American Cordillera. It also corresponds to the timing of passive margin deposition in the \"underlying\" Windermere Supergroup of the Northern Cordillera, as determined by chemostratigraphic correlations. These timing relationships imply a different breakup history for the northern, as compared to the southern, Cordillera. We propose a model that attempts to explain this paradox of Cordilleran geology. The earlier Neoproterozoic (Windermere-age) rifting event probably records breakup of a continental mass from northern Laurentia followed by development of a passive margin. Accordingly, the Windermere Supergroup of the southern Canadian Cordillera was deposited in an intracontinental rift. The second Neoproterozoic rifting (Hamill-Gog) is interpreted to indicate continental breakup and establishment of a passive margin along western Laurentia.

This paper provides a comprehensive synthesis of virtually all units and events of Early and Middle Proterozoic age in the Yukon, spanning ∼1 Ga. Early and Middle Proterozoic time was dominated by a series of extensional-basin-forming events punctuated by orogenesis, magmatism, and hydrothermal activity. Basinal deposits include the Wernecke Supergroup (>1.71 Ga), Pinguicula Group (∼1.38 Ga), and Mackenzie Mountains Supergroup (1.00-0.78 Ga).Igneous rocks include the Bonnet Plume River Intrusions (1.71 Ga), Slab volcanics (≥1.6 Ga), Hart River sills and volcanics (1.38 Ga), and Bear River (Mackenzie) dykes (1.27 Ga). A voluminous hydrothermal event generated the widespread Wernecke breccias at 1.60 Ga. The Racklan orogeny deformed the Wernecke Supergroup prior to emplacement of the Wernecke Breccia. The Corn Creek orogeny deformed Mackenzie Mountains Supergroup and older rocks prior to deposition of the Windermere Supergroup (<0.78 Ga). Long intervals with scanty rock records extended for as much as 300 Ma and appear to represent periods of crustal stability and subaerial conditions. By the time of Windermere rifting (<0.78 Ga), the supracrust of northwestern Laurentia was a mature, largely denuded orogenic belt with a composite sedimentary-metamorphic-igneous character. New isotopic data include Nd depleted mantle model ages for the Wernecke Supergroup (2.28-2.69 Ga) and Wernecke Breccia (2.36-2.96 Ga), a U-Pb zircon age for a Hart River sill 1381.9+5.3-3.7 (Ma), detrital U-Pb zircon ages from the basal Pinguicula Group (1841-3078 Ma), detrital muscovite ages from the Mackenzie Mountains Supergroup (1037-2473 Ma), and muscovite 40Ar/39Ar cooling ages from the Wernecke Supergroup (788±8 and 980±4 Ma).

A series of boreholes in Horton Quarry, northwest Yorkshire (Horton-in-Ribblesdale Inlier) penetrated mudstones and slates belonging to the Austwick Formation (Windermere Supergroup) overlying laminated mudstones of the Ingleton Group. Illite (IC) and chlorite (ChC) crystallinity measurements indicate a metamorphic inversion between the two groups of mudrocks. The Windermere Supergroup mudrocks are mostly in the high anchizone or epizone, whereas the Ingletonian samples are lower grade in terms of IC, and are mostly deep diagenetic zone or low anchizone. Hence younger strata at higher grades rest on older strata at lower grades, creating a metamorphic inversion. Ingletonian slates exposed at Pecca Falls on the River Twiss show epizonal and anchizonal IC values, and greywacke samples from Ingleton Quarry contain pumpellyite. This suggests that grade in the Ingletonian may increase to the NW from the Horton to Ingleton inliers. K-white mica b cell dimensions show further differences between the Ingleton Group and the Windermere Supergroup. The Ingletonian samples are characterized by low b cell values (8.989–9.035, mean 9.007 Å), whereas the Windermere Supergroup has higher values in the range 9.022–9.034, mean 9.027 Å. The Windermere Supergroup values are similar to those recorded from the Windermere Supergroup of the southern Lake District, and Lower Palaeozoic rocks from the Scottish Southern Uplands, and are consistent with metamorphism in a low heat flow, convergent geotectonic setting. The Ingletonian b cell values suggest metamorphism in a higher heat flow setting, most likely an extensional basin. The metamorphic inversion at Horton and differences in K-white mica b cell dimensions suggest that the Ingleton Group and Windermere Supergroup strata evolved in different geotectonic settings and record two separate metamorphic events. The discovery of the metamorphic inversion at Horton provides further evidence in favour of an Ordovician rather than Neoproterozoic depositional age for the controversial Ingleton Group.

The youngest formations of the Neoproterozoic Windermere Supergroup in northwestern Canada (Gametrail, Blueflower, and Risky formations) record the transition from slope to shelf deposition on a prograding passive margin. Eleven facies associations are recognized, representing environments ranging from carbonate- and siliciclastic- dominated continental slope to open carbonate shelf and siliciclastic shoreface. Seven simple sequences are recognized, which can be grouped into three composite sequences. Combination of the data presented here with previous work on underlying and overlying formations indicates that the sequence-stratigraphic record is least detailed in the deepest-water facies and most detailed in shelf facies, reflecting the relative inability of high-frequency relative sea-level oscillations to affect deposition in deep-water settings. Falling-stage deposits are especially common in the upper slope region. Several major sequence boundaries (unconformities) are clustered in the interval a short distance below the Precambrian-Cambrian boundary. The most significant of these occurs high in the Blueflower Formation, not at the top of the Risky Formation as commonly inferred. This interval containing several surfaces may reflect thermal uplift related to the rifting recorded in rocks of this age in the southern Canadian Cordillera. Renewed subsidence (thermal relaxation) commenced just prior to the Neoproterozoic-Cambrian boundary, giving rise to a thick succession of shelf to nonmarine basal-Cambrian deposits. Ediacaran body fossils previously reported from the studied units occur in a range of slope to shoreface environments, including some facies that were deposited below the photic zone. The most common taxa occur across a spectrum of facies and were apparently ecological generalists.

Background Since nontuberculous mycobacterial pulmonary disease (NTM-PD) is common in middle-aged/elderly slender women at risk of osteoporosis, we hypothesized that NTM-PD could be associated with osteoporosis. The study aimed to evaluate the prevalence of osteoporosis in patients with NTM-PD compared with that in the general population and determine the factors associated with osteoporosis in the subjects, including the serum estradiol (E 2 ) and 25-hydroxyvitamin D (25OHD) levels. Methods We have recruited 228 consecutive adult patients with NTM-PD from a prospective cohort study at the Keio University Hospital, who had no history of osteoporosis or osteoporosis-associated bone fracture but underwent dual-energy X-ray absorptiometry-based bone mineral density (BMD) evaluation from August 2017–September 2019. The E 2 and 25OHD levels were measured in 165 patients with available stored serum samples. We performed multivariable logistic regression analyses for osteopenia and osteoporosis. Results Osteoporosis (T-score ≤  − 2.5) and osteopenia (T-score − 1 to − 2.5) were diagnosed in 35.1% and 36.8% of patients with NTM-PD, respectively. Compared with the general population, the proportion of osteoporosis was significantly higher in 50–59-, 60–69-, and 70–79-year-old women with NTM-PD. Multivariable analysis revealed that older age (adjusted odds ratio [aOR] for 1-year increase = 1.12; 95% confidence interval [CI] = 1.07–1.18), female sex (aOR = 36.3; 95% CI = 7.57–174), lower BMI (aOR for 1 kg/m 2 decrease = 1.37; 95% CI = 1.14–1.65), and chronic Pseudomonas aeruginosa (PA) infection (aOR = 6.70; 95% CI = 1.07–41.8) were independently associated with osteoporosis. Additionally, multivariable analysis in 165 patients whose serum E 2 and 25OHD levels were measured showed that both low E 2 levels (< 10 pg/mL) and lower 25OHD levels were independently associated with osteoporosis. Conclusions Middle-aged/elderly women with NTM-PD have a higher prevalence of osteoporosis than the general population. BMD screening should be considered in NTM-PD, especially in older females with severe diseases such as chronic PA infection and lower BMI, and low serum E 2 and 25OHD levels.

Quantifying the effects of density-dependent and density-independent factors in demographic and dispersal processes remains a major challenge in population ecology. Based on unique long-term capture—mark—recapture (CMR) data (1949—2000) on pike (Esox lucius) from Windermere, United Kingdom, we provide estimates of density-dependent and density-independent effects, under the influence of individual size and sex, on natural survival, fishing mortality, and dispersal. Because survival is expected to be related to the individual growth process, we also explore the degree of parallelism between the two processes by applying the best-supported survival model structure to individual growth data. The CMR data were analyzed using sex- and age-structured multistate models (two lake basins: north and south) assuming no seasonal variation in survival and dispersal. Total survival and dispersal probabilities were insensitive to this assumption, and capture probability was shown to be robust to assumptions about intra-annual variation in survival and dispersal. The analyses revealed that large pike (>55 cm) displayed marked basin-specific differences in survival and dispersal responses to the abundance of conspecifics in which pike from the south basin show high density dependence in survival and a low degree of density dependence in dispersal, whereas the opposite was found for those of the north basin. Both large- and small-pike dispersals were found to be dependent upon the between-basin gradient in perch (Perca fluviatilis, the main prey) abundance, but most so for north-to-south dispersal. The strength and pattern of density-dependent mortality in small pike was influenced by temperature in a peculiar way: at low summer temperatures survival was lowest at high small-pike abundances and low perch abundances; at low temperatures, survival was lowest at high small-pike abundances and high perch abundances. Analyses of individual small-pike growth trajectories showed a similar modulation of the positive perch abundance effect on growth rate when temperature increases. The growth analysis also indicated that cannibalism may be biased in favor of rapidly growing individuals or at least increased growth rate for the surviving individuals. Altogether, this study provides evidence of a complex interplay between density-dependent and density-independent factors affecting survival, dispersal, and individual growth of an aquatic top predator.

An invasive species is defined as an alien (or introduced or non-native) species whose establishment and spread threaten ecosystems, habitats or species with harm. Such threats to UK lake fish communities have long been appreciated and this review assembles case histories, including new data, from the largest lakes of Scotland, Northern Ireland, Wales and England to examine the hypothesis that at least some of these introductions have become invasive. Loch Lomond in Scotland has experienced six introductions [chub (Leuciscus cephalus), common bream (Abramis brama), crucian carp (Carassius carassius), dace (Leuciscus leuciscus), gudgeon (Gobio gobio) and ruffe (Gymnocephalus cernuus)], of which the most significant has been that of the percid ruffe, which has been implicated in a recent decline of the native coregonid whitefish (Coregonus lavaretus). In Northern Ireland, the introduction of the cyprinid roach (Rutilus rutilus) to Lough Neagh has apparently had a negative impact on some overwintering waterfowl, although the native coregonid pollan (Coregonus autumnalis) remains abundant. Llyn Tegid in Wales has received three introductions [rudd (Scardinius erythrophthalmus), ruffe and silver bream (Blicca bjoerkna)], although no impacts on the native whitefish or other fish populations have been observed. In England, individuals of at least 12 native and non-native fish species have been brought to Windermere for the purpose of live-baiting, although only those of the cyprinids roach and common bream have established abundant populations. At the same time, the native salmonid Arctic charr (Salvelinus alpinus) has declined markedly while the native esocid pike (Esox lucius) has shown changes in abundance, distribution and individual condition, although these developments have not been shown to be causally linked. None of these introductions were sanctioned by appropriate fisheries or other regulatory bodies and almost all of them probably arose from the release or escape of live-bait used by pike anglers. Of the 10 species introductions documented here, four (common bream, gudgeon, roach and ruffe) have established abundant populations and two of these (roach and ruffe) have apparently caused or currently threaten harm, supporting the hypothesis that at least some of these introductions have become invasive.