1,318 research outputs found
A geothermal plant from a time-scale perspective
In recent years, geothermal energy use from low-temperature sandstone reservoirs has sharply increased. Nonetheless, the injection of heat-depleted geothermal fluids has not been an easy task because of well/formation damage and operational/economic issues. Sønderborg geothermal plant is a case example of heat-mining from a low-temperature reservoir. It is in the northeast of Sønderborg towards Augustenborg Fjord. The present work takes into consideration the regional and local geology of the Sønderborg area, construction of the wells, field experience and water chemistry. The main issues of the geothermal plant appear to be related to the construction of the wells and reinjection of the heat-depleted brine. Our water chemistry analysis and PHREEQC simulations indicate that geothermal brine was saturated with respect to carbonate and barite minerals. The excess of Ca2+ and SO42â ions could have led to the formation and precipitation of carbonate and sulfate scales. Moreover, the increment of iron concentration over time could suggest the ingress of oxygen and pitting corrosion due to the presence of halide ions
The Oslo Health Study: A Dietary Index Estimating Frequent Intake of Soft Drinks and Rare Intake of Fruit and Vegetables Is Negatively Associated with Bone Mineral Density
Background.
Since nutritional factors may affect bone mineral
density (BMD), we have investigated
whether BMD is associated with an index estimating
the intake of soft drinks, fruits, and vegetables. Methods.
BMD was measured in
distal forearm in a subsample of the population-based Oslo Health
Study. 2126 subjects had both valid BMD
measurements and answered all the questions
required for calculating a Dietary
Index = the sum of intake estimates of
colas and non-cola beverages divided by the sum
of intake estimates of fruits and vegetables. We
did linear regression analyses to study whether
the Dietary Index and the single food items
included in the index were associated with BMD.
Results. There was a consistent
negative association between the Dietary Index
and forearm BMD. Among the single index
components, colas and non-cola soft drinks were
negatively associated with BMD. The negative
association between the Dietary Index and BMD
prevailed after adjusting for gender, age, and
body mass index, length of education, smoking,
alcohol intake, and physical activity.
Conclusion. An index reflecting
frequent intake of soft drinks and rare intake
of fruit and vegetables was inversely related to
distal forearm bone mineral
density
Definition of Fiducial Points in the Normal Seismocardiogram
Abstract The purpose of this work is to define fiducial points in the seismocardiogram (SCG) and to correlate them with physiological events identified in ultrasound images. For 45 healthy subjects the SCG and the electrocardiogram (ECG) were recorded simultaneously at rest. Immediately following the SCG and ECG recordings ultrasound images of the heart were also obtained at rest. For all subjects a mean SCG signal was calculated and all fiducial points (peaks and valleys) were identified and labeled in the same way across all signals. Eight physiologic events, including the valve openings and closings, were annotated from ultrasound as well and the fiducial points were correlated with those physiologic events. A total of 42 SCG signals were used in the data analysis. The smallest mean differences (ÂąSD) between the eight events found in the ultrasound images and the fiducial points, together with their correlation coefficients (r) were: atrial systolic onset: â2 (Âą16) ms, râ=â0.75 (pâ<â0.001); peak atrial inflow: 13 (Âą19) ms, râ=â0.63 (pâ<â0.001); mitral valve closure: 4 (Âą11) ms, râ=â0.71 (pâ<â0.01); aortic valve opening: â3 (Âą11) ms, râ=â0.60 (pâ<â0.001); peak systolic inflow: 13 (Âą23) ms, râ=â0.42 (pâ<â0.01); aortic valve closure: â5 (Âą12) ms, râ=â0.94 (pâ<â0.001); mitral valve opening: â7 (Âą19) ms, râ=â0.87 (pâ<â0.001) and peak early ventricular filling: â18 (Âą28âms), râ=â0.79 (pâ<â0.001). In conclusion eight physiologic events characterizeing the cardiac cycle, are associated with reproducible, well-defined fiducial points in the SCG
Pakistanis living in Oslo have lower serum 1,25-dihydroxyvitamin D levels but higher serum ionized calcium levels compared with ethnic Norwegians. The Oslo Health Study
Background
Persons of Pakistani origin living in Oslo have a much higher prevalence of vitamin D deficiency and secondary hyperparathyroidism but similar bone mineral density compared with ethnic Norwegians. Our objective was to investigate whether Pakistani immigrants living in Oslo have an altered vitamin D metabolism by means of compensatory higher serum levels of 1,25-dihydroxyvitamin D (s-1,25(OH)2D) compared with ethnic Norwegians; and whether serum levels of ionized calcium (s-Ca2+) differ between Pakistanis and Norwegians.
Methods
In a cross-sectional, population-based study venous serum samples were drawn from 94 Pakistani men and 67 Pakistani women aged 30â60 years, and 290 Norwegian men and 270 Norwegian women aged 45â60 years; in total 721 subjects.
Results
Pakistanis had lower s-1,25(OH)2D compared with Norwegians (p < 0.001). Age- and gender adjusted mean (95% CI) levels were 93 (86, 99) pmol/l in Pakistanis and 123 (120, 126) pmol/l in Norwegians, p < 0.001. The difference persisted after controlling for body mass index. There was a positive relation between serum 25-hydroxyvitamin D (s-25(OH)D) and s-1,25(OH)2D in both groups. S-Ca2+ was higher in Pakistanis; age-adjusted mean (95% CI) levels were 1.28 (1.27, 1.28) mmol/l in Pakistanis and 1.26 (1.26, 1.26) mmol/l in Norwegians, p < 0.001. In both groups, s-Ca2+ was inversely correlated to serum intact parathyroid hormone levels (s-iPTH). For any s-iPTH, s-Ca2+ was higher in Pakistanis, also when controlling for age.
Conclusion
Community-dwelling Pakistanis in Oslo with low vitamin D status and secondary hyperparathyroidism have lower s-1,25(OH)2D compared with ethnic Norwegians. However, the Pakistanis have higher s-Ca2+. The cause of the higher s-Ca2+ in Pakistanis in spite of their higher iPTH remains unclear
Potential exposure to endocrine disrupting chemicals and selected adverse pregnancy outcomes:a follow-up study of pregnant women referred for occupational counselling
BACKGROUND: Experimental evidence indicates that fetal exposure to xenobiotics with the potential to interfere with the endogenous steroid hormone regulation of fetal development may reduce birth weight. However, epidemiological studies are limited. The aim of the study was to investigate whether potential occupational exposure to endocrine disrupting chemicals (EDC) of the mother during pregnancy is associated with preterm birth and low birth weight. METHODS: Pregnant women referred to an Occupational Health Clinic (OHC) in two Danish regions (Copenhagen or Aarhus) between 1984 and 2010, suspected of being exposed to occupational reproductive hazards were included in the study. A job exposure matrix enabled estimation of potential occupational exposure to EDC on the basis of job title. Births by women potentially exposed to EDC (nâ=â582) were compared to births by women referred to an OHC on the suspicion of other exposures than EDC (nâ=â620), and to a sample of births by all occupationally active women in the same geographical regions (nâ=â346,544), including 1,077 births of the referred womenâs non-referred pregnancies. RESULTS: No indications of reduced birth weight or increased risk of preterm birth were found among women potentially exposed to EDC. Women potentially exposed to EDC had children with a higher birth weight compared to the sample of occupationally active women but not compared to other women referred to an OHC. CONCLUSIONS: Potential maternal exposure to EDC at Danish workplaces is not related to low birth weight or preterm birth among women referred to occupational counselling. Occupational exposures might be too weak on the average to cause these adverse effects or counselling at the OHCs is effective in preventing them
The association between alcohol consumption and risk of hip fracture differs by age and gender in Cohort of Norway: a NOREPOS study
Under embargo until: 13.07.2019Summary: The association between alcohol consumption and hip fracture differed by gender: Men aged 30â59 years drinking frequently or 14+ gl/week had higher risk than moderate drinkers. No significant association was seen in older men. Women not drinking alcohol had higher risk than those drinking moderately both regarding frequency and amount. Introduction: We aimed to examine alcohol consumption and risk of hip fracture according to age and gender in the population-based Cohort of Norway (1994â2003). Methods: Socio-demographics, lifestyle, and health were self-reported and weight and height were measured in 70,568 men and 71,357 women âĽâ30 years. Information on subsequent hip fractures was retrieved from hospitalsâ electronic patient registries during 1994â2013. Frequency of alcohol consumption was categorized: never/seldom, moderate (â¤â2â3 times/week), or frequent (âĽâ4 times/week), and amount as number of glasses per week: 0, 1â6, 7â13, 14â27, and 28+. Type of alcohol (wine vs. beer/hard liquor) was also examined. Coxâs proportional hazards regression was used to estimate hazard ratios (HRs) stratified on gender and baseline age <â60 and âĽâ60 years. Results: During median 15-year follow-up, 1558 men and 2511 women suffered a hip fracture. Using moderate drinkers as reference, men <â60 years drinking frequently had multivariable adjusted HRâ=â1.73 (CI 1.02â2.96) for hip fracture and more than 2.5 times higher risk if they consumed 14+ glasses compared to 1â6 glasses per week. In other groups of age and gender, no statistically significant increased risk was found in those consuming the highest levels of alcohol. Compared to women with moderate or frequent alcohol use, never/seldom-drinking women had the highest fracture risk. In women, use of wine was associated with lower fracture risk than other types of alcohol. Conclusions: Risk of hip fracture was highest in men <â60 years with the highest frequency and amount of alcohol consumption and in non-drinking women.acceptedVersio
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