411 research outputs found
Undersøkelser av hydrokarboner i sedimenter fra MAREANO-omrüdet 2006-2009
Institute of Marine Research has analysed approximately 1600 samples from sediment cores from 63 places in the MAREANO area, sampled in south-western Barents Sea and off the coast of Lofoten islands in 2006-2009.
Sedimentological data obtained by Norwegian Geological Survey for sediments from the same area was combined with the measurements of hydrocarbons (PAH and total hydrocarbon content, THC). Low levels of hydrocarbons are found at all the locations, corresponding to KLIF classes I and II for PAH16, witb an increase
in combustion-related PAH in modern sediment layers at coastal and southernmost locations. An increase in oilrelated PAH in deep sediments found a few places near known oil- and gas-fields is attributed to natural sources
Petroleum-related hydrocarbons in deep and subsurface sediments from South-Western Barents Sea
Subsurface sediments from a pockmark area in South-Western Barents Sea have been earlier found to contain elevated levels of petroleum-related polycyclic aromatic hydrocarbons. This work describes a comprehensive analysis of various biomarkers, including the highly source-specific hopanes, in a 4.5 m long gravity core from the same area, together with subsurface sediment samples from other areas in the region without pockmarks present (âbackground samplesâ). A clear difference between the pockmark gravity core and the background sediment cores was found, both with regard to genesis and the level of transformation of organic matter. A number of indicator parameters, such as methylphenanthrene index (MPI-1), point towards a significantly higher maturity of hydrocarbons in the pockmark core throughout its length as compared to the other sampled locations. Higher contents of microbial hopanoids (hopenes) may indicate the former presence of petroleum. These findings confirm the hypothesis of a natural hydrocarbon source in the deeper strata present in the studied location with pockmarks
Phase Transitions in Rotating Neutron Stars
As rotating neutron stars slow down, the pressure and the density in the core
region increase due to the decreasing centrifugal forces and phase transitions
may occur in the center. We extract the analytic behavior near the critical
angular velocity , where the phase transitions occur in the center of
a neutron star, and calculate the moment of inertia, angular velocity, rate of
slow down, braking index, etc. For a first order phase transition these
quantities have a characteristic behavior, e.g., the braking index diverges as
. Observational consequences for first, second
and other phase transitions are discussed.Comment: 5 pages, one figure included, revtex latex styl
Comparison of treatment with insulin degludec and glargine U100 in patients with type 1 diabetes prone to nocturnal severe hypoglycaemia:The HypoDeg randomized, controlled, open-label, crossover trial
AIM: To investigate whether the longâacting insulin analogue insulin degludec compared with insulin glargine U100 reduces the risk of nocturnal symptomatic hypoglycaemia in patients with type 1 diabetes (T1D). METHODS: Adults with T1D and at least one episode of nocturnal severe hypoglycaemia during the last 2âyears were included in a 2âyear prospective, randomized, open, multicentre, crossover trial. A total of 149 patients were randomized 1:1 to basalâbolus therapy with insulin degludec and insulin aspart or insulin glargine U100 and insulin aspart. Each treatment period lasted 1âyear and consisted of 3âmonths of runâin or crossover followed by 9âmonths of maintenance. The primary endpoint was the number of blindly adjudicated nocturnal symptomatic hypoglycaemic episodes. Secondary endpoints included the occurrence of severe hypoglycaemia. We analysed all endpoints by intentionâtoâtreat. RESULTS: Treatment with insulin degludec resulted in a 28% (95% CI: 9%â43%; P = .02) relative rate reduction (RRR) of nocturnal symptomatic hypoglycaemia at level 1 (â¤3.9âmmol/L), a 37% (95% CI: 16%â53%; P = .002) RRR at level 2 (â¤3.0âmmol/L), and a 35% (95% CI: 1%â58%; P = .04) RRR in allâday severe hypoglycaemia compared with insulin glargine U100. CONCLUSIONS: Patients with T1D prone to nocturnal severe hypoglycaemia have lower rates of nocturnal symptomatic hypoglycaemia and allâday severe hypoglycaemia with insulin degludec compared with insulin glargine U100
Nitrogen transfer from forage legumes to nine neighbouring plants in a multi-species grassland
Legumes play a crucial role in nitrogen supply to grass-legume mixtures for ruminant fodder. To quantify N transfer from legumes to neighbouring plants in multi-species grasslands we established a grass-legume-herb mixture on a loamy-sandy site in Denmark. White clover (Trifolium repens L.), red clover (Trifolium pratense L.) and lucerne (Medicago sativa L.) were leaf-labelled with 15N enriched urea during one growing season. N transfer to grasses
(Lolium perenne L. and xfestulolium), white clover, red clover, lucerne, birdsfoot trefoil (Lotus corniculatus
L.), chicory (Cichorium intybus L.), plantain (Plantago
lanceolata L.), salad burnet (Sanguisorba minor L.)and caraway (Carum carvi L.) was assessed. Neighbouring plants contained greater amounts of N derived from white clover (4.8 gm-2) compared with red clover (2.2 gm-2) and lucerne (1.1 gm-2). Grasses having fibrous roots received greater amounts of N from legumes than dicotyledonous plants which generally have taproots. Slurry application mainly increased N transfer from legumes to grasses. During the growing season the three legumes transferred approximately 40 kg N ha-1 to neighbouring plants. Below-ground N transfer from legumes to neighbouring plants differed among nitrogen donors and nitrogen receivers and may depend on root characteristics and regrowth strategies of plant species in the multi-species grassland
Loss-of-activity-mutation in the cardiac chloride-bicarbonate exchanger AE3 causes short QT syndrome
Mutations in potassium and calcium channel genes have been associated with cardiac arrhythmias. Here, Jensen et al. show that an anion transporter chloride-bicarbonate exchanger AE3 is also responsible for the genetically-induced mechanism of cardiac arrhythmia, suggesting new therapeutic targets for this diseas
Exoplanet diversity in the era of space-based direct imaging missions
Community White Paper: submitted to the National Academy of Sciences Exoplanet Science StrategyThis white paper discusses the diversity of exoplanets that could be detected by future observations, so that comparative exoplanetology can be performed in the upcoming era of large space-based flagship missions. The primary focus will be on characterizing Earth-like worlds around Sun-like stars. However, we will also be able to characterize companion planets in the system simultaneously. This will not only provide a contextual picture with regards to our Solar system, but also presents a unique opportunity to observe size dependent planetary atmospheres at different orbital distances. We propose a preliminary scheme based on chemical behavior of gases and condensates in a planet's atmosphere that classifies them with respect to planetary radius and incident stellar flux
TOI-954 B And K2-329 B: Short-Period Saturn-Mass Planets That Test Whether Irradiation Leads To Inflation
We report the discovery of two short-period Saturn-mass planets, one transiting the G subgiant TOI-954 (TIC 44792534, V = 10.343, T = 9.78) observed in TESS sectors 4 and 5 and one transiting the G dwarf K2-329 (EPIC 246193072, V = 12.70, K = 10.67) observed in K2 campaigns 12 and 19. We confirm and characterize these two planets with a variety of ground-based archival and follow-up observations, including photometry, reconnaissance spectroscopy, precise radial velocity, and high-resolution imaging. Combining all available data, we find that TOI-954 b has a radius of and a mass of MJ and is in a 3.68 day orbit, while K2-329 b has a radius of and a mass of MJ and is in a 12.46 day orbit. As TOI-954 b is 30 times more irradiated than K2-329 b but more or less the same size, these two planets provide an opportunity to test whether irradiation leads to inflation of Saturn-mass planets and contribute to future comparative studies that explore Saturn-mass planets at contrasting points in their lifetimes
Hydrogen sulphide-induced hypometabolism in human-sized porcine kidneys
Background Since the start of organ transplantation, hypothermia-forced hypometabolism has been the cornerstone in organ preservation. Cold preservation showed to protect against ischemia, although post-transplant injury still occurs and further improvement in preservation techniques is needed. We hypothesize that hydrogen sulphide can be used as such a new preservation method, by inducing a reversible hypometabolic state in human sized kidneys during normothermic machine perfusion. Methods Porcine kidneys were connected to an ex-vivo isolated, oxygen supplemented, normothermic blood perfusion set-up. Experimental kidneys (n = 5) received a 85mg NaHS infusion of 100 ppm and were compared to controls (n = 5). As a reflection of the cellular metabolism, oxygen consumption, mitochondrial activity and tissue ATP levels were measured. Kidney function was assessed by creatinine clearance and fractional excretion of sodium. To rule out potential structural and functional deterioration, kidneys were studied for biochemical markers and histology. Results Hydrogen sulphide strongly decreased oxygen consumption by 61%, which was associated with a marked decrease in mitochondrial activity/function, without directly affecting ATP levels. Renal biological markers, renal function and histology did not change after hydrogen sulphide treatment. Conclusion In conclusion, we showed that hydrogen sulphide can induce a controllable hypometabolic state in a human sized organ, without damaging the organ itself and could thereby be a promising therapeutic alternative for cold preservation under normothermic conditions in renal transplantation
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