604 research outputs found
Vitamin D and muscle performance in athletes
No full textVitamin D supplementation has recently gained considerable attention in the sports community as a potential nutritional treatment to enhance athletic performance. Interest in vitamin D supplementation for athletes stems in part from intriguing preclinical studies of vitamin D actions on key muscle biological pathways and from data on muscle performance enhancements in older non-athletic adults. Multiple observational studies in young athletes report a direct association between vitamin D status and muscle strength, power, and recovery from musculoskeletal injury. Yet, clinical trials examining the musculoskeletal responses to supplementation with vitamin D in athletes are limited and report mixed results due in part to small sample size and differences in study design, population, and vitamin D dose. Based on meta-analyses in non-athletic populations, future clinical trials to determine the impact on athletic performance should be conducted in large samples of athletes with undisputed vitamin D deficiency at baseline
The parathyroid hormone-regulated transcriptome in osteocytes: parallel actions with 1,25-dihydroxyvitamin D(3) to oppose gene expression changes during differentiation and to promote mature cell function
No full textAbstract not availableHillary C. St. John, Mark B. Meyer, Nancy A. Benkusky, Alex H. Carlson, Mathew Prideaux, Lynda F. Bonewald, J. Wesley Pik
Letter. Late cretaceous seasonal ocean variability from the arctic
No full textThe modern Arctic Ocean is regarded as barometer of global change and amplifier of global warming1 and therefore records of past Arctic change are of a premium for palaeoclimate reconstruction. Little is known of the state of the Arctic Ocean in the greenhouse period of the late Cretaceous, yet records from such times may yield important clues to its future behaviour given current global warming trends. Here we present the first seasonally resolved sedimentary record from the Cretaceous from the Alpha Ridge of the Arctic Ocean. This “paleo-sediment trap” provides new insights into the workings of the Cretaceous marine biological carbon pump. Seasonal primary production was dominated by diatom algae but was not related to upwelling as previously hypothesised. Rather, production occurred within a stratified water column, involving specially adapted species in blooms resembling those of the modern North Pacific Subtropical Gyre, or those indicated for the Mediterranean sapropels. With increased CO2 levels and warming currently driving increased stratification in the global ocean, this style of production that is adapted to stratification may become more widespread. Our evidence for seasonal diatom production and flux testify to an ice-free summer, but thin accumulations of terrigenous sediment within the diatom ooze are consistent with the presence of intermittent sea ice in the winter, supporting a wide body of evidence for low temperatures in the Late Cretaceous Arctic Ocean, rather than recent suggestions of a 15 °C mean annual temperature at this time
The effects of 1,25 D3 on the mouse osteopontin promoter
No full text15 p.Vitamin D (1,25 D3) is an important transcriptional regulator of many genes including our gene of interest, osteopontin. Osteopontin is a known regulator of bone calcification and mineralization and is involved in signaling in the immune response. We looked at osteopontin expression in mouse MC3T3-El preosteoblast cells in response to 1,25 D3. We also tested how pathways known to crosstalk with 1,25 D3 modify mOPN expression. These include MNAR, Wnt3a conditioned media, PTH, and dexamethasone. Additionally, we checked how ZK159222, an antagonist to VDR with partial agonist activity, effects mOPN expression. The osteopontin promoter was cloned into a POL3 reporter vector and transfected into MC3T3-El cells. A luciferase assay normalized by a tl-gal assay was used to measure gene expression. 1,25 D3 induces activity of the mOPN promoter. ZK159222, MNAR, Wnt3a conditioned media, PTH, and dexamethasone were not found to effect mOPN promoter activity in the presence of 1,25 D3
Columbia River northern pike: Investigating the ecology of British Columbia's new apex invasive freshwater predator
No full textNorthern pike (Esox lucius) is a widely distributed freshwater fish in the northern hemisphere, holding both recreational and commercial value in many countries including Canada. Pike are apex predators and are well regarded as a sport fish due to their size and voraciousness, leading to a long history of introductions outside their native range in North America. Invasive pike populations can impose significant top-down pressure on native fish community structure through predation and competition for resources, and have been linked with significant reductions of a variety of native species. Pike have recently invaded the Columbia River in British Columbia downstream of the Hugh L. Keenleyside Dam, threatening important sport fisheries, local ecosystems, and Species at Risk recovery work currently being conducted in the Columbia and its tributaries. In response to the invasion, the province implemented a pike suppression program, yet several questions remain regarding the ecology and behaviour of the recently colonized population. This research aimed to answer these questions and aid in the development of a long term management strategy for the Columbia River. Four years of data collected through the suppression program were analyzed to investigate the potential risk the invasion poses to native fish communities in B.C., the status of pike in the B.C. Columbia River, and the efficacy and impacts of current efforts. A total of 352 northern pike were captured through the suppression program by gill-netting (n=323) and angler incentives (n=29), ranging in length from 260 mm to 1050 mm. Cleithra age estimates indicate pike from within this population are achieving sizes in excess of 1 m in five to six years, and are in better than average body condition (relative weight Wr used) when compared to other North American populations. A total of 584, 659, 407, and 676 gill-net hours were set in 2014, 2015, 2016, and 2017 respectively, and an overall reduction in pike catch per unit effort (CPUE) was observed from the initial year (0.19 pike/hr) to the final year (0.05 pike/hr). This suggests gill-netting has been effective at reducing the number of adult pike in B.C. and should be conducted annually. The capture of several juvenile pike (n = 14) near Castlegar in 2017 indicates spawning is occurring in B.C. and future years of suppression should include controlling the juvenile cohort. Salmonids, particularly whitefish spp., appear to be at the greatest risk from pike predation making up approximately 50% of pike diet overall. Acoustic tracking of pike indicated the majority of individuals from within this population remain relatively sedentary, yet one individual migrated in excess of 100 km between B.C. and Washington. Microchemical analysis of pike otoliths revealed significant differences in ratios of Sr and Ba to Ca between pike caught in the Columbia and Pend d’Oreille Rivers, and that a small portion of the current Columbia population in B.C. appears to have originated in the Pend d’Oreille River. Fluctuations in otolith elemental Mg concentrations also appear to provide information that can be used to estimate the age of northern pike and potentially other esocid species. Lastly, the use of environmental DNA (eDNA) sampling as a tool to monitor the presence and spread of northern pike in B.C. was explored with minimal success; the protocol used and results obtained are discussed.Esox luciusnorthern pikeinvasive speciesfisheries managementacoustic telemetryotolith microchemistr
Columbia River northern pike: Investigating the ecology of British Columbia's new apex invasive freshwater predator
No full textNorthern pike (Esox lucius) is a widely distributed freshwater fish in the northern hemisphere, holding both recreational and commercial value in many countries including Canada. Pike are apex predators and are well regarded as a sport fish due to their size and voraciousness, leading to a long history of introductions outside their native range in North America. Invasive pike populations can impose significant top-down pressure on native fish community structure through predation and competition for resources, and have been linked with significant reductions of a variety of native species. Pike have recently invaded the Columbia River in British Columbia downstream of the Hugh L. Keenleyside Dam, threatening important sport fisheries, local ecosystems, and Species at Risk recovery work currently being conducted in the Columbia and its tributaries. In response to the invasion, the province implemented a pike suppression program, yet several questions remain regarding the ecology and behaviour of the recently colonized population. This research aimed to answer these questions and aid in the development of a long term management strategy for the Columbia River. Four years of data collected through the suppression program were analyzed to investigate the potential risk the invasion poses to native fish communities in B.C., the status of pike in the B.C. Columbia River, and the efficacy and impacts of current efforts. A total of 352 northern pike were captured through the suppression program by gill-netting (n=323) and angler incentives (n=29), ranging in length from 260 mm to 1050 mm. Cleithra age estimates indicate pike from within this population are achieving sizes in excess of 1 m in five to six years, and are in better than average body condition (relative weight Wr used) when compared to other North American populations. A total of 584, 659, 407, and 676 gill-net hours were set in 2014, 2015, 2016, and 2017 respectively, and an overall reduction in pike catch per unit effort (CPUE) was observed from the initial year (0.19 pike/hr) to the final year (0.05 pike/hr). This suggests gill-netting has been effective at reducing the number of adult pike in B.C. and should be conducted annually. The capture of several juvenile pike (n = 14) near Castlegar in 2017 indicates spawning is occurring in B.C. and future years of suppression should include controlling the juvenile cohort. Salmonids, particularly whitefish spp., appear to be at the greatest risk from pike predation making up approximately 50% of pike diet overall. Acoustic tracking of pike indicated the majority of individuals from within this population remain relatively sedentary, yet one individual migrated in excess of 100 km between B.C. and Washington. Microchemical analysis of pike otoliths revealed significant differences in ratios of Sr and Ba to Ca between pike caught in the Columbia and Pend d’Oreille Rivers, and that a small portion of the current Columbia population in B.C. appears to have originated in the Pend d’Oreille River. Fluctuations in otolith elemental Mg concentrations also appear to provide information that can be used to estimate the age of northern pike and potentially other esocid species. Lastly, the use of environmental DNA (eDNA) sampling as a tool to monitor the presence and spread of northern pike in B.C. was explored with minimal success; the protocol used and results obtained are discussed.Esox luciusnorthern pikeinvasive speciesfisheries managementacoustic telemetryotolith microchemistr
A Formal Analysis of Lithic Materials from D1Pu7, Top of the World, British Columbia
No full textA survey of Top of the World Provincial Park located a quarry site and numerous "workshop" areas. A formal analysis of surface-collected lithic materials from one site located is undertaken. Mush of the surface scatter at this site (D1Pu7) is the quarried material, but many lithic materials foreign to the quarry area are also present.
Artifacts are grouped on the basis of position and extent of retouch and type of raw material utilized. A large variation within artifact classes necessitates individual description in many cases. Functional inferences are avoided. Sample inadequacies limit the data obtained, but all cores and most bifacial edges are of the quarried material, while most unifacial edges are of the foreign lithic material.Student paper for Anthropology 240.Anthropolog
Destination Marketing Organizations and destination marketing: A narrative analysis of the literature
No full textThis article presents the first narrative analysis of the areas of research that have developed within the destination marketing field since its commencement in 1973. Given the broad extent of the field, and the absence of any previous reviews in four decades, a key challenge is in providing a focus for such a disparate body of knowledge. The review is structured around one principal question: 'To what extent is the Destination Marketing Organisation (DMO) responsible for the competitiveness of the destination?'. In pursuit of this underlying question, we address a number of themes including nomenclature and the DMO, the evolution of the destination marketing literature, competitiveness as the DMO reason d'être, and DMO effectiveness including issues of branding and positioning, and future research themes in the field. © 2013 Elsevier Ltd
Adult vitamin D deficiency and adverse brain outcomes
No full textVitamin D deficiency is prevalent throughout the world, and growing evidence supports a requirement for optimal vitamin D levels for healthy brain function. Vitamin D deficiency has been associated with a wide range of neuropsychiatric disorders and neurodegenerative diseases. In addition, there is a growing body of animal experiments and in vitro studies that provide important insights into mechanisms of action linking vitamin D and adverse brain outcomes. In this chapter, we will focus on clinical studies that provide links between vitamin D deficiency and brain outcomes in adults. We also present an overview from preclinical studies on rodents, in which vitamin D deficiency during adulthood may exacerbate underlying brain disorders and/or worsen recovery from brain stressors. Vitamin D supplementation is readily available and affordable, and this review highlights the need for further research
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