A Laurentian cratonic reference from the distal Proterozoic basement of Western Newfoundland using tandem in situ and isotope dilution U-pb zircon and titanite geochronology

2021 ◽  
Vol 321 (7) ◽  
pp. 1045-1079
Author(s):  
Eben B. Hodgin ◽  
Francis A. Macdonald ◽  
James L. Crowley ◽  
Mark D. Schmitz
Keyword(s):  
Isotope Dilution ◽  
Proterozoic Basement

Effects of pancreatectomy, tolbutamide and insulin on glucose fluxes in chickens

1982 ◽  
Vol 94 (3) ◽  
pp. 429-441 ◽  
Author(s):  
R. W. Danby ◽  
I. K. Martin ◽  
W. R. Gibson
Keyword(s):  
Isotope Dilution ◽  
Glucose Utilization ◽  
Total Pancreatectomy ◽  
Single Injection ◽  
Average Rate ◽  
Extracellular Fluid ◽  
Constant Infusion ◽  
Glucose Release ◽  
Pancreatic Insulin

The effects of pancreatectomy and of injection of insulin or tolbutamide on glucose fluxes in chickens were examined. This was prompted by earlier observations that tolbutamide seems not to require the presence of pancreatic insulin for its acute hypoglycaemic action in this species. Rates of appearance (Ra) and disappearance (Rd) of glucose were estimated by isotope dilution using [14C]glucose in single-injection experiments and [14C]glucose and [6−3H]glucose in priming-injection + constant-infusion experiments. Six hours after sub-total pancreatectomy (splenic lobe remained in situ), chickens were hyperglycaemic (16·7 v. 10·4 mmol glucose/l in controls), had a larger sampled glucose pool (4·41 v. 3·10 mmol) and a higher average rate of glucose utilization (41·7 v. 33·3 μmol/kg per min) than sham-operated controls as estimated in single-injection experiments. Tolbutamide (50 mg/kg injected i.v.) reduced Ra in intact chickens from 33·9 to 1·1 μmol/kg per min and reduced Ra in pancreatectomized chickens from 42·2 to 10·2 μmol/kg per min. In priming-injection + constant-infusion experiments tolbutamide again reduced Ra significantly. In all cases Rd tended to fall, apparently as a result of the developing hypoglycaemia. Tolbutamide did not affect the volume of extracellular fluid (sucrose space). In single-injection experiments, insulin (1 unit/kg injected i.v.) reduced Ra by 56% and transiently increased Rd by 39%. It was concluded that pancreatectomy and injection of insulin or tolbutamide produce responses in glucose movements in chickens that are qualitatively similar to those in mammals. In chickens the hypoglycaemic action of tolbutamide, which persists in the absence of the pancreas, depends on an inhibition of glucose release by the liver.

scholarly journals Supplemental Material: A robust age model for the Cryogenian Pocatello Formation of southeastern Idaho (northwestern USA) from tandem in situ and isotope dilution U-Pb dating of volcanic tuffs and epiclastic detrital zircons

2022 ◽  
Author(s):  
V.H. Isakson ◽  
et al. ◽  
M.D. Schmitz
Keyword(s):  
Trace Element ◽  
Isotope Dilution ◽  
Element Concentration ◽  
Trace Element Concentration ◽  
Detrital Zircons ◽  
Field Of View ◽  
Pb Isotope ◽  
Concentration Data ◽  
Age Model

<div>Figure S1. Thin-section photomicrographs for lithologies of the Bannock Volcanic Member and Scout Mountain Member of the Pocatello Formation exposed at Scout Mountain, Idaho. Sample numbers are illustrated on the stratigraphic section of Figure 4. Field of view is 24 mm × 40 mm. Tables S1–S3: LA-ICPMS U-Pb isotope and trace element concentration data. Table S4: CA-IDTIMS U-Pb isotope data.<br></div>

scholarly journals Supplemental Material: A robust age model for the Cryogenian Pocatello Formation of southeastern Idaho (northwestern USA) from tandem in situ and isotope dilution U-Pb dating of volcanic tuffs and epiclastic detrital zircons

2022 ◽  
Author(s):  
V.H. Isakson ◽  
et al. ◽  
M.D. Schmitz
Keyword(s):  
Trace Element ◽  
Isotope Dilution ◽  
Element Concentration ◽  
Trace Element Concentration ◽  
Detrital Zircons ◽  
Field Of View ◽  
Pb Isotope ◽  
Concentration Data ◽  
Age Model

<div>Figure S1. Thin-section photomicrographs for lithologies of the Bannock Volcanic Member and Scout Mountain Member of the Pocatello Formation exposed at Scout Mountain, Idaho. Sample numbers are illustrated on the stratigraphic section of Figure 4. Field of view is 24 mm × 40 mm. Tables S1–S3: LA-ICPMS U-Pb isotope and trace element concentration data. Table S4: CA-IDTIMS U-Pb isotope data.<br></div>

Rendez vous with Saturn's rings

1984 ◽  
Vol 75 ◽  
pp. 743-759 ◽  
Author(s):  
Kerry T. Nock
Keyword(s):  
Solar Energy ◽  
Electric Propulsion ◽  
Power Source ◽  
Propulsion System ◽  
Low Thrust ◽  
Ring Plane ◽  
The Earth ◽  
Total Impulse ◽  
Saturn's Rings

ABSTRACTA mission to rendezvous with the rings of Saturn is studied with regard to science rationale and instrumentation and engineering feasibility and design. Future detailedin situexploration of the rings of Saturn will require spacecraft systems with enormous propulsive capability. NASA is currently studying the critical technologies for just such a system, called Nuclear Electric Propulsion (NEP). Electric propulsion is the only technology which can effectively provide the required total impulse for this demanding mission. Furthermore, the power source must be nuclear because the solar energy reaching Saturn is only 1% of that at the Earth. An important aspect of this mission is the ability of the low thrust propulsion system to continuously boost the spacecraft above the ring plane as it spirals in toward Saturn, thus enabling scientific measurements of ring particles from only a few kilometers.

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