Memorial University of Newfoundland

About: Memorial University of Newfoundland is a education organization based out in St. John's, Newfoundland and Labrador, Canada. It is known for research contribution in the topics: Population & Context (language use). The organization has 13818 authors who have published 27785 publications receiving 743594 citations. The organization is also known as: Memorial University & Memorial University of Newfoundland and Labrador.

Condition, prolonged swimming performance and muscle metabolic capacities of cod Gadus morhua.

Abstract: SUMMARY This study evaluated the link between swimming endurance and condition of Atlantic cod Gadus morhua that had been fed or starved during the 16 weeks preceding the tests, and assessed whether muscle metabolic capacities explain such links. The condition factor [(somatic mass × fork length -3 )×100] of starved cod was 0.54±0.1 whereas that of fed cod was 0.81±0.1. In white and red muscle, we measured four glycolytic enzymes: phosphofructokinase (PFK), pyruvate kinase (PK), creatine kinase (CK) and lactate dehydrogenase (LDH), two mitochondrial enzymes: cytochrome c oxidase (CCO) and citrate synthase (CS), a biosynthetic enzyme, nucleoside diphosphate kinase (NDPK), glycogen and protein levels and water content. Muscle samples were taken at three positions along the length of the fish; starvation affected the metabolic capacities of white muscle more than those of red muscle. The levels of glycolytic enzymes and glycogen changed more in white than red muscle during starvation. Both in fed and starved cod, muscle metabolic capacities varied with position along the fish; starvation reduced this longitudinal variation more in white than red muscle. In white muscle of fed cod, the glycolytic enzyme levels increased from head to tail, while in starved cod this longitudinal variation disappeared. In red muscle mitochondrial enzyme levels were highest in the caudal sample, but fewer differences were found for glycolytic enzymes. Swimming endurance was markedly affected by fish condition, with starved fish swimming only 30% of the time (and distance) of fed fish. This endurance was closely linked with the number of burst—coast movements during the test and the activity of CCO and LDH in white muscle. The number of burst—coast movements was significantly linked with condition factor and PFK activity in caudal red muscle and gill arch mass. Our data indicated that cod use both glycolytic and oxidative capacities to support endurance swimming. Furthermore, swimming endurance is linked with the metabolic capacities of red and white muscle.

Integrated records of environmental change and evolution challenge the Cambrian Explosion

Abstract: The 'Cambrian Explosion' describes the rapid increase in animal diversity and abundance, as manifest in the fossil record, between ~540 and 520 million years ago (Ma). This event, however, is nested within a far more ancient record of macrofossils extending at least into the late Ediacaran at ~571 Ma. The evolutionary events documented during the Ediacaran-Cambrian interval coincide with geochemical evidence for the modernisation of Earth's biogeochemical cycles. Holistic integration of fossil and geochemical records leads us to challenge the notion that the Ediacaran and Cambrian worlds were markedly distinct, and places biotic and environmental change within a longer-term narrative. We propose that the evolution of metazoans may have been facilitated by a series of dynamic and global changes in redox conditions and nutrient supply, which, potentially together with biotic feedbacks, enabled turnover events that sustained multiple phases of radiation. We argue that early metazoan diversification should be recast as a series of successive, transitional radiations that extended from the late Ediacaran and continued through the early Palaeozoic. We conclude that while the Cambrian Explosion represents a radiation of crown-group bilaterians, it was simply one phase amongst several metazoan radiations, some older and some younger.

Attitudes of health sciences students towards interprofessional teamwork and education

Abstract: Relatively little is known about the specific attributes of health professional students which may influence their attitudes towards both interprofessional teamwork and interprofessional education. A survey was distributed to all pre-licensure health professional students from medicine, nursing, pharmacy and social work programmes at our institution. Respondents were asked to rate their attitudes towards interprofessional healthcare teams and interprofessional education using validated and reliable scales reported in the literature. Information on the respondents’ gender, profession, year of study and prior experience with interprofessional education was also collected. There was no significant difference between attitudes of medicine and nursing students towards interprofessional teamwork; however, both these student groups report significantly less positive attitudes towards interprofessional teams than pharmacy and social work students. Medicine students reported significantly less positive attitudes towards interprofessional education than nursing, pharmacy and social work students. Female students and senior undergraduate students reported significantly more positive attitudes towards interprofessional teamwork and interprofessional education, while students reporting prior experience with interprofessional education reported significantly more positive attitudes towards interprofessional teamwork. Profession, gender and year of study appear to be attributes which were related to more positive attitudes towards both interprofessional teamwork and education.

Motion sickness symptoms in a ship motion simulator: effects of inside, outside, and no view.

Abstract: Vehicle motion characteristics differ between air, road, and sea environments, both vestibularly and visually. Effects of vision on motion sickness have been studied before, though less systematically in a naval setting. It is hypothesized that appropriate visual information on self-motion is beneficial in a naval setting and that task performance is likely reduced as sickness increases. Methods : Using a within-subjects design, 24 subjects were exposed to 30 min of motion in a ship’s bridge motion simulator with 3 visual conditions: an Earth-fixed outside view; an inside view that moved with the subjects; and a blindfolded condition. Subjective sickness symptoms and severity were rated repeatedly before, during, and after motion exposure. During the motion, subjects performed a mental task. Results : Though not excessive, sickness was highest in the inside viewing condition, intermediate in the outside viewing condition, and least in the blindfolded condition. The blindfolded condition was equally as bad as the inside viewing condition during the first 5-10 min of motion exposure. The overall temporal increase of sickness during motion was about equal to the decrease during recovery. No effect of sickness on task performance was observed. Discussion : Most sickness in a naval setting is observed when the visual environment moves with the subjects, as has been reported in other environments, such as cars. Only mild sickness, caused by moderate motions, was provoked in this study and was alleviated by the performance task. A non-linear brain mechanism integrating visual and vestibular information may explain why the least sickness was observed when subjects were blindfolded.

Giving the early fossil record of sponges a squeeze.

Abstract: Twenty candidate fossils with claim to be the oldest representative of the Phylum Porifera have been re-analysed. Three criteria are used to assess each candidate: (i) the diagnostic criteria needed to categorize sponges in the fossil record; (ii) the presence, or absence, of such diagnostic features in the putative poriferan fossils; and (iii) the age constraints for the candidate fossils. All three criteria are critical to the correct interpretation of any fossil and its placement within an evolutionary context. Our analysis shows that no Precambrian fossil candidate yet satisfies all three of these criteria to be a reliable sponge fossil. The oldest widely accepted candidate, Mongolian silica hexacts from c. 545 million years ago (Ma), are here shown to be cruciform arsenopyrite crystals. The oldest reliable sponge remains are siliceous spicules from the basal Cambrian (Protohertzina anabarica Zone) Soltanieh Formation, Iran, which are described and analysed here in detail for the first time. Extensive archaeocyathan sponge reefs emerge and radiate as late as the middle of the Fortunian Stage of the Cambrian and demonstrate a gradual assembly of their skeletal structure through this time coincident with the evolution of other metazoan groups. Since the Porifera are basal in the Metazoa, their presence within the late Proterozoic has been widely anticipated. Molecular clock calibration for the earliest Porifera and Metazoa should now be based on the Iranian hexactinellid material dated to c. 535 Ma. The earliest convincing fossil sponge remains appeared at around the time of the Precambrian-Cambrian boundary, associated with the great radiation events of that interval.