6,675 research outputs found
Accretionary origin for the late Archean Ashuanipi Complex of Canada
The Ashuanipi complex is one of the largest massif granulite terrains of the Canadian Shield. It makes up the eastern end of the 2000 km long, lower-grade, east-west belts of the Archean Superior Province, permitting lithological, age and tectonic correlation. Numerous lithological, geochemical and metamorphic similarities to south Indian granulites suggest common processes and invite comparison of tectonic evolution. The Ashuanipi granulite terrain of the Cannadian Superior Province was studied in detail, and an origin through self-melting of a 55 km thick accretionary wedge seems possible
Coexisting serpentine and quartz from carbonate-bearing serpentinized peridotite in the Samail Ophiolite, Oman
Tectonically exposed mantle peridotite in the Oman Ophiolite is variably serpentinized and carbonated. Networks of young carbonate veins are prevalent in highly serpentinized peridotite, particularly near low-temperature alkaline springs emanating from the peridotite. An unusual feature in some samples is the coexistence of serpentine and quartz, which is not commonly observed in serpentinites. This assemblage is unstable with respect to serpentine + talc or talc + quartz under most conditions. Serpentine in the carbonated serpentinites in this study is more iron rich than in most serpentinites reported in previous studies, and samples with co-existing quartz contain the most iron-rich serpentines. Calculations of thermodynamic equilibria in the MgO–SiO2–H2O–CO2 system suggest that serpentine + quartz may be a stable assemblage at low temperatures (e.g., <~15–50 °C) and is stabilized to higher temperatures by preferential cation substitutions in serpentine over talc. Based on these calculations, serpentine + quartz assemblages could result from serpentinization at near-surface temperatures. Clumped isotope thermometry of carbonate veins yields temperatures within error of the observed temperatures in Oman groundwater for all samples analyzed, while the δ^18O of water calculated to be in equilibrium with carbonate precipitated at those temperatures is within error of the observed isotopic composition of Oman groundwater for the majority of samples analyzed. As groundwater geochemistry suggests that carbonate precipitation and serpentinization occur concomitantly, this indicates that both hydration and carbonation of peridotite are able to produce extensive alteration at the relatively low temperatures of the near-surface weathering environment
Effects of a multi-component exercise program and calcium–vitamin-D3-fortified milk on bone mineral density in older men : a randomised controlled trial
Summary We examined the independent and combined effects of a multi-component exercise program and calcium–vitamin-D3-fortified milk on bone mineral density (BMD) in older men. Exercise resulted in a 1.8% net gain in femoral neck BMD, but additional calcium–vitamin D3 did not enhance the response in this group of older well-nourished men.Introduction This 12-month randomised controlled trial assessed whether calcium–vitamin-D3-fortified milk could enhance the effects of a multi-component exercise program on BMD in older men.Methods Men (n  = 180) aged 50–79 years were randomised into: (1) exercise + fortified milk; (2) exercise; (3) fortified milk; or (4) controls. Exercise consisted of high intensity progressive resistance training with weight-bearing impact exercise. Men assigned to fortified milk consumed 400 mL/day of low fat milk providing an additional 1,000 mg/day calcium and 800 IU/day vitamin D3. Femoral neck (FN), total hip, lumbar spine and trochanter BMD and body composition (DXA), muscle strength 25-hydroxyvitamin D and parathyroid hormone (PTH) were assessed.Results There were no exercise-by-fortified milk interactions at any skeletal site. Exercise resulted in a 1.8% net gain in FN BMD relative to no-exercise (p < 0.001); lean mass (0.6 kg, p < 0.05) and muscle strength (20–52%, p < 0.001) also increased in response to exercise. For lumbar spine BMD, there was a net 1.4–1.5% increase in all treatment groups relative to controls (all p < 0.01). There were no main effects of fortified milk at any skeletal site.Conclusion A multi-component community-based exercise program was effective for increasing FN BMD in older men, but additional calcium–vitamin D3 did not enhance the osteogenic response.<br /
Analysis of skeletal development on the basis of body mass and bone resorption
An article written by Darrin L. DeMoss and published in the 2000 issue of Life Sciences, pages 1397-1407
Dietary fibre as a unifying remedy for the whole spectrum of obesity-associated cardiovascular risk
Obesity is a pandemic carrying the heavy burden of multiple and serious co-morbidities including metabolic syndrome, type 2 diabetes and cardiovascular diseases. The pathophysiological processes leading to the accumulation of body fat slowly evolve to fat accumulation in other body compartments than subcutaneous tissue. This abnormal fat deposition determines insulin resistance which in turn causes blood glucose and lipid metabolism derangement, non-alcoholic fatty liver disease, hypertension, and metabolic syndrome. All these conditions contribute to increase the cardiovascular risk of obese people. Several randomized clinical trials demonstrated that moderate weight loss (5–10%) in obese patients improves obesity-related metabolic risk factors and coexisting disorders. Therefore, nutritional strategies able to facilitate weight management, and in the meantime positively influence obesity-associated cardiovascular risk factors, should be implemented. To this aim, a suitable option could be dietary fibres that may also act independently of weight loss. The present narrative review summarizes the current evidence about the effects of dietary fibres on weight management in obese people. Moreover, all of the different cardiovascular risk factors are individually considered and evidence on cardiovascular outcomes is summarized. We also describe the plausible mechanisms by which different dietary fibres could modulate cardio-metabolic risk factors. Overall, despite both epidemiological and intervention studies on weight loss that show statistically significant but negligible clinical effects, dietary fibres seem to have a beneficial impact on main pathophysiological pathways involved in cardiovascular risk (i.e., insulin resistance, renin-angiotensin, and sympathetic nervous systems). Although the evidence is not conclusive, this suggests that fibre would be a suitable option to counteract obesity-related cardio-metabolic diseases also independently of weight loss. However, evidence is not consistent for the different risk factors, with clear beneficial effects shown on blood glucose metabolism and Low Density Lipoprotein (LDL) cholesterol while there is fewer, and less consistent data shown on plasma triglyceride and blood pressure. Ascribing the beneficial effect of some foods (i.e., fruits and vegetables) solely to their fibre content requires more investigation on the pathophysiological role of other dietary components, such as polyphenols
Assessment of a global positioning system to evaluate activities of organic chickens at pasture
The aims of the present study were to assess the use of a global positioning system (GPS) monitoring device to evaluate the activities of organic chickens at pasture. Two hundred male birds from 2 strains (100 slow-growing and 100 fast-growing birds) were reared separately in 4 indoor pens (0.10 m2/bird), each with access to a grass paddock (10 m2/bird; 2 replications/ genotype). During the last week of age (from 73 to 80 d of age), the kinetic activity of chickens was monitored by behavioral observations (n = 20; focal bird sampling method) and a GPS (n = 10; Super Trackstick, Atex International, Route d'Esch, Luxembourg) equipped with a universal serial bus port for quick viewing on Google Earth's 3-D model, giving information concerning the date, hour, environmental conditions, and coordinates of monitored birds. Based on the focal bird sampling method, fast-growing birds tended to stay indoors rather than forage in the pasture, whereas slow-growing birds spent more time outdoors (P < 0.05). Moreover, visual observations confirmed GPS records, whereas slow growing birds were observed to perform more active behaviors stand less, and spend more time outdoors than indoors. Based on GPS tracks, slow-growing chickens covered an average daily distance of 1,230 m, whereas fastgrowing birds covered only 125 m. In conclusion, GPS appears to be a suitable way to evaluate the kinetic activity of chickens. We also concluded that locomotor activity, which requires a high energy consumption, is low in fast-growing birds compared with slow-growing ones, allowing the fast-growing birds to reallocate energy to productive traits
Parentage assignment of progeny in mixed milt fertilization of Caspian brown trout Salmo trutta caspius using microsatellite DNA markers: Implications for conservation
Parentage of a stock of mixed milt produced progeny in current artificial breeding protocol of endangered Caspian brown trout, Salmo trutta caspius, was determined using three microsatellite loci chosen after a primary analysis of genetic diversity at nine microsatellite loci in the eight used breeder individuals. Overall, 98.8% of progeny were assigned to their parents using Family Assignment Program (FAP). Selection of hyper-variable microsatellites in Caspian brown trout to identify unique alleles was effective for unambiguous parentage determination and estimation of genetic diversity in this study. Effective population size of breeder individuals (Ne) was lower than the number of breeder individuals used (Nb) indicating unbalanced contribution of breeder individuals to progeny. Indeed, one of the four male breeder individuals produced about 70 % and the other three produced only from 4.86 % to 18.83 % of progeny. The average observed and expected heterozygosity of progeny (0.723 ± 0.011 and 0.684 ± 0.009, respectively) was significantly lower than that of their parents (0.833 and 0.800, respectively). Our data indicate that the current breeding protocol of Caspian brown trout may not provide equal opportunity for all the breeder individuals to contribute equally to progeny. Therefore, appropriate fertilization designs in the hatchery should be established in order to equalize the genetic contribution of different breeder individualsS
Parentage assignment of progeny in mixed milt fertilization of Caspian brown trout Salmo trutta caspius using microsatellite DNA markers: Implications for conservation
Parentage of a stock of mixed milt produced progeny in current artificial breeding protocol of endangered Caspian brown trout, Salmo trutta caspius, was determined using three microsatellite loci chosen after a primary analysis of genetic diversity at nine microsatellite loci in the eight used breeder individuals. Overall, 98.8% of progeny were assigned to their parents using Family Assignment Program (FAP). Selection of hyper-variable microsatellites in Caspian brown trout to identify unique alleles was effective for unambiguous parentage determination and estimation of genetic diversity in this study. Effective population size of breeder individuals (Ne) was lower than the number of breeder individuals used (Nb) indicating unbalanced contribution of breeder individuals to progeny. Indeed, one of the four male breeder individuals produced about 70 % and the other three produced only from 4.86 % to 18.83 % of progeny. The average observed and expected heterozygosity of progeny (0.723 ± 0.011 and 0.684 ± 0.009, respectively) was significantly lower than that of their parents (0.833 and 0.800, respectively). Our data indicate that the current breeding protocol of Caspian brown trout may not provide equal opportunity for all the breeder individuals to contribute equally to progeny. Therefore, appropriate fertilization designs in the hatchery should be established in order to equalize the genetic contribution of different breeder individuals.Key words: Parentage assignment, effective population size, genetic diversity, Salmo trutta caspius
Effects of Selenium on Colon Carcinogenesis Induced by Azoxymethane and Dextran Sodium Sulfate in Mouse Model with High-Iron Diet
Selenium (Se) is known to prevent several cancers while the relationship between high iron and the risk of colorectal cancer is controversial. To investigate the effects of Se in colon carcinogenesis, we subjected three different levels of Se and high-iron diet to a mouse model of colon cancer in which animals were treated with three azoxymethane (AOM) injections followed by dextran sodium sulfate (DSS) administration. There were five experimental groups including vehicle group [normal-Fe (NFe, 45 ppm)+medium-Se (MSe, 0.1 ppm)], positive control group (AOM/DSS+NFe+MSe), AOM/DSS+high-Fe (HFe, 450 ppm)+low-Se (LSe, 0.02 ppm), AOM/DSS+HFe+MSe, and AOM/DSS+HFe+high-Se (HSe, 0.5 ppm). The animals were fed on the three different Se diets for 24 weeks. The incidence of colon tumor in the high-Se diet group (AOM/DSS+HFe+HSe) showed 19.4% lower than positive control group, 5.9% lower than AOM/DSS+HFe+MSe diet group, and 11.1% lower than AOM/DSS+HFe+LSe group. The tumor multiplicity was significantly higher in the low-Se diet group (AOM/DSS+HFe+LSe) compare to all other AOM/DSS treated groups. In the high-Se diet group, the activity of hepatic GPx was comparable to that of positive control group, and significantly higher than those of low-Se or medium-Se diet groups. Expression level of hepatic GPx-1 showed similar results. Hepatic malondialdehyde (MDA) level (indicator of oxidative stress) in the low-Se diet group showed the highest compared to the other groups, and it was significantly higher than positive control group. In the high-Se diet group the level of MDA in the liver was significantly lower than all other AOM/DSS treated groups. High-Se diet group showed significantly lower proliferative index than low-Se and medium-Se groups. The apoptotic indices in low-Se group and medium-Se group were significantly lower than positive control group. However, apoptotic index of high-Se diet group was significantly higher than all other AOM/DSS treated groups. These findings suggest that dietary Se supplement may have protective effect against colon cancer by decreasing proliferation, increasing apoptosis of tumor cells, and reducing oxidative stress in mice with high iron diet
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