2,870 research outputs found
A common garden design reveals population-specific variability in potential impacts of hybridisation between populations of farmed and wild Atlantic salmon, Salmo salar L
Released individuals can have negative impacts on native populations through various mechanisms; including competition, disease transfer and introduction of maladapted gene-complexes. Previous studies indicate that the level of farmed Atlantic salmon introgression in native populations is population-specific. However few studies have explored the potential role of population diversity or river characteristics, such as temperature, on the consequences of hybridisation. We compared freshwater growth of multiple families derived from two farmed, five wild, and two F1 hybrid salmon populations at three contrasting temperatures (7°C, 12°C, and 16°C) in a common garden experiment. As expected, farmed salmon outgrew wild salmon at all temperatures, with hybrids displaying intermediate growth. However, differences in growth were population-specific and some wild populations performed better than others relative to the hybrid and farmed populations at certain temperatures. Therefore, the competitive balance between farmed and wild salmon may depend both on the thermal profile of the river and the genetic characteristics of the respective farmed and wild strains. While limited to F1 hybridisation, the present study shows the merits in adopting a more complex spatially resolved approach to risk management of local populations
Evaluating Alternative Measures of Bicycling Level of Traffic Stress Using Crowdsourced Route Satisfaction Data
Approaches for evaluating the quality of bicycling have become increasingly important for planning bicycle infrastructure improvements. Mekuria, Furth, and Nixon’s (2012) “Level of Traffic Stress” (LTS) approach, which requires minimal data inputs and produces a simple and intuitive output, has emerged as a widely-used framework for identifying streets that are “low-stress” for cyclists. The LTS framework is based on a hierarchy of characteristics, largely related to traffic speed and roadway layout, that are presumed to cause higher or lower levels of stress. Despite the apparent simplicity of LTS, several key challenges emerge from its application. Firstly, multiple LTS classification methods have been developed, and it is difficult to know whether they represent stress in equivalent ways. Secondly, LTS is intended only to define an ordinal scale of stressfulness, but has often been misinterpreted as defining a continuous scale; there is no intended implication that the stress levels are spaced equally. Third, while LTS provides a useful summary of diverse infrastructural variables, it is poorly understood which of these variables are most strongly associated with cyclist satisfaction and may, therefore, be most important to capture in an LTS framework.
These challenges were examined in the contexts of two U.S. cities: Portland, Oregon, which has a very well-developed bicycling infrastructure, and Austin, Texas, which has more moderately-developed bicycling infrastructure. In both cities, LTS outcomes differed depending on the LTS classification method used. In addition, even when classified using the same method, LTS outcomes differed depending on the source of the data used. This suggests that LTS analyses based on different methods or data sources are unlikely to be comparable. Associations between LTS classifications and continuously-scaled user satisfaction data from the crowdsourcing mobile app Ride Report suggested that LTS levels represented a fairly linear scale, though differences in average Ride Report scores between successive LTS levels were rarely large. Ride Report user satisfaction data were most strongly and consistently associated with variables related to bicycling-specific infrastructure, such as bike lanes and boulevards, and indicators of street size. These variables may be most useful for developing LTS classification methods with minimal data inputs. Unsurprisingly, our analysis also supports the addition of bicycle-specific infrastructure and reduction of roadway size and traffic volume as among the most effective approaches for reducing LTS levels and maximizing user satisfaction along cycling networks
Intersection of Indigenous Peoples and Police: Questions about Contact and Confidence
Despite much anecdotal, journalistic, and statistical evidence of their oppression by colonial and neocolonial police practices, little is known about Indigenous peoples’ attitudes towards the police in Canada. Th e theory that involuntary police–citizen contacts increase citizens’ mistrust, fear, and dissat- isfaction and, ultimately, decreases confi dence in the police was advanced. Hypotheses arising from this historical-theoretical context were tested with the 2014 panel of Canada’s General Social Survey, including 951 Indigenous (First Nations, Métis, or Inuit) and 21,576 non-Indigenous white participants. Indigenous identity and involuntary contacts were both signifi cantly associated with a lack of confi dence in police, p \u3c .001. As hypothesized, the odds associated with involuntary contacts (odds ratio [OR] = 2.66) were stronger than those associated with being Indigenous (OR = 1.81). While the hypothesized ethnicity by contact interaction was not observed, Indigenous participants (5%) were two and a half times as likely as non-Indigenous white participants (2%) to have had relatively frequent (two or more) involuntary contacts with the police during the past year. Th erefore, at the population level Indigenous people are at much greater risk of coming into involuntary contact with the police and of consequently lacking confi dence in police. Policy implications and future research needs are discussed
Modulation of endothelial cell integrity and inflammatory activation by commercial lipid emulsions
BACKGROUND: Thrombosis and immune dysfunction are two important complications that result from the administration of parenteral nutrition. Endothelial cells within the vasculature are crucial components necessary for maintenance of normal coagulation and immune function.
METHODS: We compared the effects of three commercial lipid emulsions (LEs; Intralipid®, ClinOleic® [or Clinolipid®], and Omegaven®) differing in the levels of omega-6 polyunsaturated fatty acids, omega-3 polyunsaturated fatty acids, omega-9 monounsaturated fatty acids, and saturated fatty acids upon endothelial cell fatty acid composition using Gas chromatography, endothelial cell integrity by assessing measurement of apoptosis and necrosis using flow cytometry, endothelial cell inflammatory activation by assessing the induction of ICAM-1 by lipopolysaccharide [LPS]), and transcription factor activation (phosphorylation of NF-κB) using western blot analysis.
RESULTS: Gas chromatographic analysis confirmed cellular uptake of the fatty acids within the LEs; furthermore, these fatty acid changes reflected the composition of the oils and egg phosphatides used in the manufacturing of these emulsions. However, the kinetics of fatty acid uptake and processing differed between LEs. Fish oil LE negatively impacted cell viability by doubling the percentage of apoptotic and necrotic cell populations quantified by flow cytometry using Annexin V/Fluorescein and propidium iodide. The soybean oil LE did not alter cell viability, while the olive oil-predominate emulsion improved cell viability. All LEs were capable of suppressing LPS-induced ICAM-1 expression; however, the fish oil LE was more potent than the other emulsions. Fish oil LE supplementation of cells also suppressed LPS-induced phosphorylation of NF-ÎşB, while the soybean oil and olive predominant LE had no effect upon NF-ÎşB phosphorylation.
CONCLUSIONS: Lipid emulsions are readily incorporated and stored in the form of triacylglycerols. Soybean oil-based, olive oil-predominant and fish-oil based LEs differentially affected endothelial cell integrity. Importantly, these three LEs were capable of suppressing endothelial cell inflammatory response despite their fatty acid content
Tocopherol and tocotrienol homologs in parenteral lipid emulsions
Parenteral lipid emulsions, which are made of oils from plant and fish sources, contain different types of tocopherols and tocotrienols (vitamin E homologs). The amount and types of vitamin E homologs in various lipid emulsions vary considerably and are not completely known. The objective of this analysis was to develop a quantitative method to determine levels of all vitamin E homologs in various lipid emulsions. An HPLC system was used to measure vitamin E homologs using a Pinnacle DB Silica normal phase column and an isocratic, n-hexane:1,4 dioxane (98:2) mobile phase. An optimized protocol was used to report vitamin E homolog concentrations in soybean oil-based (Intralipid®, Ivelip®, Lipofundin® N, Liposyn® III, and Liposyn® II), medium- and long-chain fatty acid-based (Lipofundin®, MCT and Structolipid®), olive oil-based (ClinOleic®), and fish oil-based (Omegaven®) and mixture of these oils-based (SMOFlipid®, Lipidem®) commercial parenteral lipid emulsions. Total content of all vitamin E homologs varied greatly between different emulsions, ranging from 57.9 to 383.9 µg/mL. Tocopherols (α, β, γ, δ) were the predominant vitamin E homologs for all emulsions, with tocotrienol content < 0.3%. In all of the soybean emulsions, except for Lipofundin® N, the predominant vitamin E homolog was γ-tocopherol, which ranged from 57-156 µg/mL. ClinOleic® predominantly contained α-tocopherol (32 µg/mL), whereas α-tocopherol content in Omegaven® was higher than most of the other lipid emulsions (230 µg/mL).
PRACTICAL APPLICATIONS:
The information on the types and quantity of vitamin E homologs in various lipid emulsions will be extremely useful to physicians and healthcare personnel in selecting appropriate lipid emulsions that are exclusively used in patients with inadequate gastrointestinal function, including hospitalized and critically ill patients. Some emulsions may require vitamin E supplementation in order to meet minimal human requirements
Physical Processes Dictate Early Biogeochemical Dynamics of Soil Pyrogenic Organic Matter in a Subtropical Forest Ecosystem
Quantifying links between pyOM dynamics, environmental factors and processes is central to predicting ecosystem function and response to future perturbations. In this study, changes in carbon (TC), nitrogen (TN), pH, and relative recalcitrance (R50) for pineand cordgrass-derived pyOM were measured at 3–6 weeks intervals throughout the first year of burial in the soil. Objectives were to (1) identify key environmental factors and processes driving early-stage pyOM dynamics, and (2) develop quantitative relationships between environmental factors and observed changes in pyOM properties. The study was conducted in sandy soils of a forested ecosystem within the Longleaf pine range of the United States with a focus on links between changes in pyOM properties, fire history (FH), cumulative precipitation (Pcum), average temperature (Tavg) and soil residence time (SRT). Pcum, SRT and Tavg were the main factors controlling TC and TN accounting for 77–91% and 64–96% of their respective variability. Fire history, along with Pcum, SRT and Tavg, exhibited significant controlling effects on pyOM pH and R50—accounting for 48–91% and 88–93% of respective variability. Volatilization of volatiles and leaching of water-soluble components (in summer) and the sorption of exogenous organic matter (fall through spring) were most plausibly controlling pyOM dynamics in this study. Overall, our results point to climatic and land management factors and physicochemical process as the main drivers of pyOM dynamics in the pine ecosystems of the Southeastern U
Can You Swim? Self-Report and Actual Swimming Competence Among Young Adults in Ballarat, Australia
This paper reports the Australian findings in an international study comparing self-reported and actual swimming and aquatic skills of young adults. Physical Education and Sports Sciences students (n=263) completed the “Can You Swim?” self-report survey and practical skills assessment, unaware that the practical tests replicated survey items. Relationships for comparisons between practical tests and their matched survey item were weak, indicating participants had inaccurate perceptions of their own swimming skills. Typically, they underestimated their competence in terms of distance and fundamental aquatic skills. Understanding of what constitutes different levels of swimming ability was poor, for example, most participants identified as average or good to excellent swimmers, but more than half of self-identified average swimmers, and 20% of good to excellent swimmers, estimated they could complete \u3c100m of continuous swimming. The implications of study findings for drowning prevention and the need for further research are discussed
1U Chassis Accepts PCIe or PXIe Cards
PCIe and PXIe are both open-standards for expansion and I/O cards, both enabling the end user of the system to configure the desired I/O to suit their needs. The problem is that the two cards are not space-compatible, requiring systems manufacturers to create two separate product to address both markets. This article discloses a means that allows for a flexible architecture that can accept either a PCIe bay or a PXIe bay, thus enabling both types of I/O, PCIe and PXIe, to be supported in a common-design, and in this example, a system that can be mounted in a standard 19” rack that consumes only 1U of rack space
Comparative study of the modulation of fructose/sucrose-induced hepatic steatosis by mixed lipid formulations varying in unsaturated fatty acid content
BACKGROUND: Non-alcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease in developed countries. NAFLD encompasses a spectrum of diseases, ranging from hepatic steatosis to non-alcoholic steatohepatitis (NASH), cirrhosis, and liver failure. The etiology of NAFLD remains unclear but is thought to relate to increased fatty acid flux within the liver that results in toxic fatty acid metabolite production. One source of increased fatty acid flux is fructose/sucrose-induced hepatic lipogenesis. Current treatment for NAFLD encompasses dietary modifications. However, little scientific evidence exists on which to base many dietary recommendations, especially the intake of different types of carbohydrates and fats. We hypothesized that lipid mixtures of unsaturated fatty acids would inhibit lipogenesis and subsequent hepatic steatosis induced by high carbohydrate diets. The aim of this study was to examine the effects of different complex mixtures of fatty acids upon the development of fructose/sucrose-induced hepatic steatosis.
METHODS: C57BL/6 mice were randomized to normocaloric chow-based diets that varied in the type of carbohydrate (starch, sucrose, fructose). Animals in each carbohydrate group were further randomized to diets that varied in lipid type (no additional lipid, soybean oil, fish oil, olive/soybean oil, macadamia nut oil). These oils were chosen based upon their content of omega-6 polyunsaturated fatty acids, omega-3 polyunsaturated fatty acids, omega-9 monounsaturated fatty acids, or omega-7 monounsaturated fatty acids. Fatty acid flux in the liver was determine by assessing hepatic lipid content (steatosis). We also assessed fatty acid levels in the plasma and liver of the animals, hepatic lipogenesis activity, hepatic stearoyl-CoA-1 desaturase activity, and hepatic elongase activity.
RESULTS: Animals consumed similar amounts of the diets and maintained normal body weights throughout the study. Both sucrose and fructose induced hepatic lipogenesis and steatosis, with fructose being more potent. All mixed lipids similarly inhibited steatosis, limiting lipid content to levels found in the control (starch) animals. Lipogenesis and stearoyl-CoA-1 desaturase activity were increased in the sucrose and fructose groups. Levels of these enzymatic processes remained at baseline in all of the lipid groups.
CONCLUSION: This is the first study to compare various complex lipid mixtures, based upon dietary oils with different types of long-chain fatty acids, upon development of sucrose/fructose-induced steatosis. Both carbohydrate source and lipid content appear important for the modulation of steatosis. Moderate intake of complex lipids with high unsaturated to saturated fatty acid ratios inhibited both lipogenesis and steatosis
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