1,321 research outputs found

    Kinship and marriage in early Arabia

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    Miniaturized data loggers and computer programming improve seabird risk and damage assessments for marine oil spills in Atlantic Canada

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    Obtaining useful information on marine birds that can aid in oil spill (and other hydrocarbon release) risk and damage assessments in offshore environments is challenging. Technological innovations in miniaturization have allowed archival data loggers to be deployed successfully on marine birds vulnerable to hydrocarbons on water. A number of species, including murres (both Common, Uria aalge, and Thick-billed, U. lomvia) have been tracked using geolocation devices in eastern Canada, increasing our knowledge of the seasonality and colony-specific nature of their susceptibility to oil on water in offshore hydrocarbon production areas and major shipping lanes. Archival data tags are starting to resolve questions around behaviour of vulnerable seabirds at small spatial scales relevant to oil spill impact modelling, specifically to determine the duration and frequency at which birds fly at sea. Advances in data capture methods using voice activated software have eased the burden on seabird observers who are collecting increasingly more detailed information on seabirds during ship-board and aerial transects. Computer programs that integrate seabird density and bird behaviour have been constructed, all with a goal of creating more credible seabird oil spill risk and damage assessments. In this paper, we discuss how each of these technological and computing innovations can help define critical inputs into seabird risk and damage assessments, and when combined, can provide a more realistic understanding of the impacts to seabirds from any hydrocarbon release

    Looking to the future: predicting renal replacement outcomes in a large community cohort with chronic kidney disease

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    Background Chronic kidney disease (CKD) is common and important due to poor outcomes. An ability to stratify CKD care based on outcome risk should improve care for all. Our objective was to develop and validate 5-year outcome prediction tools in a large population-based CKD cohort. Model performance was compared with the recently reported ‘kidney failure risk equation’ (KFRE) models. Methods Those with CKD in the Grampian Laboratory Outcomes Mortality and Morbidity Study-I (3396) and -II (18 687) cohorts were used to develop and validate a renal replacement therapy (RRT) prediction tool. The discrimination, calibration and overall performance were assessed. The net reclassification index compared performance of the developed model and the 3- and 4-variable KFRE model to predict RRT in the validation cohort. Results The developed model (with measures of age, sex, excretory renal function and proteinuria) performed well with a C-statistic of 0.938 (0.918–0.957) and Hosmer–Lemeshow (HL) χ2 statistic 4.6. In the validation cohort (18 687), the developed model falsely identified fewer as high risk (414 versus 3278 individuals) compared with the KFRE 3-variable model (measures of age, sex and excretory renal function), but had more false negatives (58 versus 21 individuals). The KFRE 4-variable model could only be applied to 2274 individuals because of a lack of baseline urinary albumin creatinine ratio data, thus limiting its use in routine clinical practice. Conclusions CKD outcome prediction tools have been developed by ourselves and others. These tools could be used to stratify care, but identify both false positives and -negatives. Further refinement should optimize the balance between identifying those at increased risk with clinical utility for stratifying care

    Nitrative and Oxidative Stress in Toxicology and Disease

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    Persistent inflammation and the generation of reactive oxygen and nitrogen species play pivotal roles in tissue injury during disease pathogenesis and as a reaction to toxicant exposures. The associated oxidative and nitrative stress promote diverse pathologic reactions including neurodegenerative disorders, atherosclerosis, chronic inflammation, cancer, and premature labor and stillbirth. These effects occur via sustained inflammation, cellular proliferation and cytotoxicity and via induction of a proangiogenic environment. For example, exposure to the ubiquitous air pollutant ozone leads to generation of reactive oxygen and nitrogen species in lung macrophages that play a key role in subsequent tissue damage. Similarly, studies indicate that genes involved in regulating oxidative stress are altered by anesthetic treatment resulting in brain injury, most notable during development. In addition to a role in tissue injury in the brain, inflammation, and oxidative stress are implicated in Parkinson's disease, a neurodegenerative disease characterized by the loss of dopamine neurons. Recent data suggest a mechanistic link between oxidative stress and elevated levels of 3,4-dihydroxyphenylacetaldehyde, a neurotoxin endogenous to dopamine neurons. These findings have significant implications for development of therapeutics and identification of novel biomarkers for Parkinson's disease pathogenesis. Oxidative and nitrative stress is also thought to play a role in creating the proinflammatory microenvironment associated with the aggressive phenotype of inflammatory breast cancer. An understanding of fundamental concepts of oxidative and nitrative stress can underpin a rational plan of treatment for diseases and toxicities associated with excessive production of reactive oxygen and nitrogen species

    Definitions of progression in chronic kidney disease-predictors and relationship to renal replacement therapy in a population cohort with a 6 year follow-up

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    Background. Chronic kidney disease (CKD) is common, important and associated with increased healthcare needs due to CKD progression. Definitions of renal disease progression are multiple, and not always comparable. A measure of 'progression' directly comparable with renal replacement therapy (RRT) initiation would identify 'progressors' in research and for healthcare planning.Methods. The Grampian Laboratory Outcomes Morbidity and Mortality Study (GLOMMS-I) is a community cohort with CKD from 2003, followed up to June 2009 for (i) RRT initiation and (ii) 'progression': sustained reduction in estimated glomerular filtration rate (eGFR) by 15 mL/min/1.73 m(2) (equivalent to CKD stage change), or to <10 mL/min/1.73 m(2), whichever occurs first. Predictors were baseline demographics and comorbidity. The use of the Kidney Disease: Improving Global Outcomes-2012 progression definition was also explored.Results. Two thousand two hundred and eighty-nine and 1044 had Stage 3 and 4 CKD, 44% were males. Overall, RRT initiation and progression rates were 0.97 and 3.50 per 100 patient-years (py). Females had significantly lower progression and RRT initiation rates. The progression rate was not dependent on CKD stage [incidence rate ratio (IRR) for Stage 4 (versus Stage 3) 0.9 (95% CI 0.8-1.2)], whereas the RRT initiation rate was [IRR 5.6 (95% CI 3.8-8.2)]. Increased proteinuria was associated with both greater RRT initiation and progression rates.Conclusions. Progression and RRT initiation rate ratios allow comparison of predictors of these outcomes. Higher rates of both in males suggest that greater RRT initiation rate is biological rather than due to preferential treatment. Similar progression but very different RRT initiation rates in Stage 3 and 4 CKD suggests that CKD stage effect on RRT initiation is a function of endpoint proximity rather than faster renal function deterioration.Background. Chronic kidney disease (CKD) is common, important and associated with increased healthcare needs due to CKD progression. Definitions of renal disease progression are multiple, and not always comparable. A measure of 'progression' directly comparable with renal replacement therapy (RRT) initiation would identify 'progressors' in research and for healthcare planning.Methods. The Grampian Laboratory Outcomes Morbidity and Mortality Study (GLOMMS-I) is a community cohort with CKD from 2003, followed up to June 2009 for (i) RRT initiation and (ii) 'progression': sustained reduction in estimated glomerular filtration rate (eGFR) by 15 mL/min/1.73 m(2) (equivalent to CKD stage change), or to <10 mL/min/1.73 m(2), whichever occurs first. Predictors were baseline demographics and comorbidity. The use of the Kidney Disease: Improving Global Outcomes-2012 progression definition was also explored.Results. Two thousand two hundred and eighty-nine and 1044 had Stage 3 and 4 CKD, 44% were males. Overall, RRT initiation and progression rates were 0.97 and 3.50 per 100 patient-years (py). Females had significantly lower progression and RRT initiation rates. The progression rate was not dependent on CKD stage [incidence rate ratio (IRR) for Stage 4 (versus Stage 3) 0.9 (95% CI 0.8-1.2)], whereas the RRT initiation rate was [IRR 5.6 (95% CI 3.8-8.2)]. Increased proteinuria was associated with both greater RRT initiation and progression rates.Conclusions. Progression and RRT initiation rate ratios allow comparison of predictors of these outcomes. Higher rates of both in males suggest that greater RRT initiation rate is biological rather than due to preferential treatment. Similar progression but very different RRT initiation rates in Stage 3 and 4 CKD suggests that CKD stage effect on RRT initiation is a function of endpoint proximity rather than faster renal function deterioration

    The effects of inspiratory muscle training in older adults

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    Purpose: Declining inspiratory muscle function and structure and systemic low-level inflammation and oxidative stress may contribute to morbidity and mortality during normal ageing. Therefore, we examined the effects of inspiratory muscle training (IMT) in older adults on inspiratory muscle function and structure and systemic inflammation and oxidative stress, and re-examined the reported positive effects of IMT on respiratory muscle strength, inspiratory muscle endurance, spirometry, exercise performance, physical activity levels (PAL) and quality of life (QoL). Methods: Thirty-four healthy older adults (68 ± 3 years) with normal spirometry, respiratory muscle strength and physical fitness were divided equally into a pressure-threshold IMT or sham-hypoxic placebo group. Before and after an 8 week intervention, measurements were taken for dynamic inspiratory muscle function and inspiratory muscle endurance using a weighted plunger pressure-threshold loading device, diaphragm thickness using B-mode ultrasonography, plasma cytokine concentrations using immunoassays, DNA damage levels in peripheral blood mononuclear cells (PBMC) using Comet Assays, spirometry, maximal mouth pressures, exercise performance using a six minute walk test, PAL using a questionnaire and accelerometry, and QoL using a questionnaire

    Circadian variation in muscle force output in males using isokinetic, isometric dynamometry: can we observe this in multi-joint movements using the muscleLab force-velocity encoder and are they similar in peak and magnitude?

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    We have investigated the magnitude of circadian variation in Isokinetic and Isometric strength of the knee extensors and flexors, as well as back squat and bench press performance using the MuscleLab force velocity transducer. Ten resistance-trained males (mean±SD: age 21.5 ± 1.1 years; body mass 78.3 ± 5.2 kg; height 1.71 ± 0.07 m) underwent a) three to four familiarization sessions on each dynamometer and b) four sessions at different times of day (03:00, 09:00, 15:00 and 21:00 h). Each session was administered in a counterbalanced order and included a period when Perceived onset of mood states (POMS), then rectal and muscle temperature (Trec, Tm) was measured at rest, after which a 5-min standardized 150 W warm-up was performed on a cycle ergometer. Once completed, Isokinetic (60 and 240°·s−1 for extension and flexion) and Isometric dynamometry with peak torque (PT), time-to-peak-torque (tPT) and peak force (PF) and % activation was measured. Lastly, Trec and Tm were measured before the bench press (at 30, 50 and 70 kg) and back squat (at 40, 60 and 80 kg) exercises. A linear encoder was attached to an Olympic bar used for the exercises and average force (AF), peak velocity (PV) and time-to-peak-velocity (tPV) were measured (MuscleLab software; MuscleLab Technology, Langesund, Norway) during the concentric phase of the movements. Five-min recovery was allowed between each set with three repetitions being completed. General linear models with repeated measures and cosinor analysis were used to analyse the data. Values for Trec and Tm at rest were higher in the evening compared to morning values (Acrophase Φ: 16:35 and 17:03 h, Amplitude A: 0.30 and 0.23°C, Mesor M: 36.64 and 37.43°C, p < 0.05). Vigor, happy and fatigue mood states responses showed Φ 16:11 and 16:03 h and 02:05 h respectively. Circadian rhythms were apparent for all variables irrespective of equipment used where AF, PF and PT values peaked between 16:18 and 18:34 h; PV, tPV and tPT peaked between 05:54 and 08:03 h (p < 0.05). In summary, circadian rhythms in force output (force, torque, power, and velocity) were shown for isokinetic, isometric dynamometers and complex multi-joint movements (using a linear encoder); where tPV and tPT occur in the morning compared to the evening. Circadian rhythms in strength can be detected using a portable, low-cost instrument that shows similar cosinor characteristics as established dynamometers. Hence, muscle-strength can be measured in a manner that is more directly transferable to the world of athletic and sports performance
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