Cratonic reactivation in the Precambrian basement of western Canada. Part II. Metasomatism and isostasy

1970 ◽  
Vol 7 (5) ◽  
pp. 1275-1294 ◽  
Author(s):  
R. A. Burwash ◽  
J. Krupička
Keyword(s):  
Large Scale ◽  
Marked Change ◽  
Potassium Feldspar ◽  
Average Density ◽  
Age Dating ◽  
Low Grade ◽  
Precambrian Basement ◽  
Isotopic Age ◽  
Clear Cut

Large-scale deformation of crystalline rocks coupled with metasomatic recrystallization during the Hudsonian orogeny (~1800 m.y. ago) determined the main features of a large portion of the western Canadian Precambrian basement (the Athabasca mobile zone) and its subsequent geological history. The following are the main changes resulting from deformation and metasomatic recrystallization in the Athabasca mobile zone:(a) Significant increase in K2O and Rb, significant decrease in CaO, MgO, Na2O, and Sr, and almost unchanged Al2O3 and SiO2. These changes reflect the relative mobility of major oxides. The very marked change in the Rb/Sr ratio constitutes an important disturbing factor for isotopic age dating.(b) Marked increase in potassium feldspar combined with very marked increase in secondary minerals (epidote, chlorite, muscovite), clear-cut decrease in plagioclase and primary dark minerals, and only a slight increase in quartz. The coexistence of newly-formed microcline and low-grade minerals cannot be explained by disequilibrium.(c) Decrease in the average density of deformed and K-metasomatized complexes, and the probable subsequent long-term isostatic adjustments in the western Canadian sedimentary basin.

scholarly journals Quantitative Monetary Easing and Risk in Financial Asset Markets

2006 ◽  
Vol 6 (1) ◽  
pp. 1-54 ◽  
Author(s):  
Takeshi Kimura ◽  
David H. Small
Keyword(s):  
Interest Rates ◽  
Large Scale ◽  
Corporate Bonds ◽  
Asset Markets ◽  
Low Grade ◽  
Short Term ◽  
Government Bonds ◽  
Risk Premiums ◽  
Portfolio Rebalancing

In this paper, we empirically examine the portfolio-rebalancing effects stemming from the policy of “quantitative monetary easing” recently undertaken by the Bank of Japan when the nominal short-term interest rate was virtually at zero. Portfolio-rebalancing effects resulting from the open market purchase of long-term government bonds under this policy have been statistically significant. Our results also show that the portfolio-rebalancing effects were beneficial in that they reduced risk premiums on assets with counter-cyclical returns, such as government and high-grade corporate bonds. But, they may have generated the adverse effects of increasing risk premiums on assets with pro-cyclical returns, such as equities and low-grade corporate bonds. These results are consistent with a CAPM framework in which business-cycle risk importantly affects risk premiums. Our estimates capture only some of the effects of quantitative easing and thus do not imply that the complete set of effects were adverse on net for Japan’s economy. However, our analysis counsels caution in accepting the view that, ceteris paribus, a massive large-scale purchase of long-term government bonds by a central bank provides unambiguously positive net benefits to financial markets at zero short-term interest rates.

Cratonic reactivation in the Precambrian basement of western Canada. I. Deformation and chemistry

1969 ◽  
Vol 6 (6) ◽  
pp. 1381-1396 ◽  
Author(s):  
R. A. Burwash ◽  
J. Krupička
Keyword(s):  
Large Scale ◽  
Sedimentary Basin ◽  
Low Grade ◽  
Western Canada ◽  
Isotopic Age ◽  
Great Slave Lake ◽  
Southern Alberta ◽  
Close Relationship ◽  
Metamorphic Facies ◽  
Index Mineral

The study of petrographic, chemical, and physical properties of 183 unweathered drill cores from oil wells which have penetrated the crystalline basement underlying the Western Canadian sedimentary basin supplements previous data from this area. For the investigated area of approximately 400 000 miles2 (1 000 000 km2), lying between the latitudes 49° and 62 °N, the available data suggest the following: (i) The existence of a broad, east northeast–west southwest striking mobile zone between Great Slave Lake and southern Alberta and central Saskatchewan (the Athabasca mobile zone) containing a high proportion of largely pre-Hudsonian crystalline rocks, which underwent strong postcrystalline deformation and metasomatic recrystallization (poly-metamorphism) during the Hudsonian orogeny, 1700–1900 m.y. ago. (ii) A close relationship between the degree of postcrystalline (syn-crystalline) deformation and the intensity of metasomatic recrystallization. (iii) The possibility of large-scale regional K-metasomatism and granitization in deformed crystalline zones leading to microclinization of acid and intermediate rocks,(iv) A high proportion of reworked older rocks and the probable non-eugeosynclinal character of the metamorphosed supracrustal rocks in the mobile zone, (v) The very strong influence of postcrystalline deformation and recrystallization upon isotopic age determinations, (vi) The wide coexistence of newly formed microcline with low-grade minerals like chlorite and epidote, challenging the validity of the use of microcline as a metamorphic facies index mineral.

scholarly journals Temporal Lobe Epilepsy in Children

2012 ◽  
Vol 2012 ◽  
pp. 1-16 ◽  
Author(s):  
Katherine C. Nickels ◽  
Lily C. Wong-Kisiel ◽  
Brian D. Moseley ◽  
Elaine C. Wirrell
Keyword(s):  
Temporal Lobe Epilepsy ◽  
Temporal Lobe ◽  
Hippocampal Sclerosis ◽  
Low Grade ◽  
Temporal Area ◽  
Clear Cut ◽  
Intractable Seizures ◽  
Ictal Eeg ◽  
Eeg Pattern

The temporal lobe is a common focus for epilepsy. Temporal lobe epilepsy in infants and children differs from the relatively homogeneous syndrome seen in adults in several important clinical and pathological ways. Seizure semiology varies by age, and the ictal EEG pattern may be less clear cut than what is seen in adults. Additionally, the occurrence of intractable seizures in the developing brain may impact neurocognitive function remote from the temporal area. While many children will respond favorably to medical therapy, those with focal imaging abnormalities including cortical dysplasia, hippocampal sclerosis, or low-grade tumors are likely to be intractable. Expedient workup and surgical intervention in these medically intractable cases are needed to maximize long-term developmental outcome.

Evolution of Large-Scale Coronal Structures

1994 ◽  
Vol 144 ◽  
pp. 29-33
Author(s):  
P. Ambrož
Keyword(s):  
Magnetic Field ◽  
Field Line ◽  
Large Scale ◽  
Coronal Magnetic Field ◽  
Source Surface ◽  
Solar Cycles ◽  
Characteristic Relationship ◽  
The Magnetic Field ◽  
Coronal Structures

AbstractThe large-scale coronal structures observed during the sporadically visible solar eclipses were compared with the numerically extrapolated field-line structures of coronal magnetic field. A characteristic relationship between the observed structures of coronal plasma and the magnetic field line configurations was determined. The long-term evolution of large scale coronal structures inferred from photospheric magnetic observations in the course of 11- and 22-year solar cycles is described.Some known parameters, such as the source surface radius, or coronal rotation rate are discussed and actually interpreted. A relation between the large-scale photospheric magnetic field evolution and the coronal structure rearrangement is demonstrated.

Computer Analyses in Preventive Health Research

1967 ◽  
Vol 06 (01) ◽  
pp. 8-14 ◽  
Author(s):  
M. F. Collen
Keyword(s):  
Medical Research ◽  
Preventive Medicine ◽  
Health Research ◽  
Large Scale ◽  
Preventive Health ◽  
New Era ◽  
Large Numbers ◽  
Normal Test ◽  
Computer Analyses

The utilization of an automated multitest laboratory as a data acquisition center and of a computer for trie data processing and analysis permits large scale preventive medical research previously not feasible. Normal test values are easily generated for the particular population studied. Long-term epidemiological research on large numbers of persons becomes practical. It is our belief that the advent of automation and computers has introduced a new era of preventive medicine.

Efficient Co-Harvesting of Solar Energy and Low-Grade Heat by Molecular Photoswitches for High Energy Density, Long-Term Stable Solar Thermal Battery

2019 ◽  
Author(s):  
Zhao-Yang Zhang ◽  
Tao LI
Keyword(s):  
Energy Density ◽  
Solar Energy ◽  
High Performance ◽  
High Energy ◽  
Solar Thermal ◽  
High Energy Density ◽  
Low Grade ◽  
Thermal Battery ◽  
Low Grade Heat

Solar energy and ambient heat are two inexhaustible energy sources for addressing the global challenge of energy and sustainability. Solar thermal battery based on molecular switches that can store solar energy and release it as heat has recently attracted great interest, but its development is severely limited by both low energy density and short storage stability. On the other hand, the efficient recovery and upgrading of low-grade heat, especially that of the ambient heat, has been a great challenge. Here we report that solar energy and ambient heat can be simultaneously harvested and stored, which is enabled by room-temperature photochemical crystal-to-liquid transitions of small-molecule photoswitches. The two forms of energy are released together to produce high-temperature heat during the reverse photochemical phase change. This strategy, combined with molecular design, provides high energy density of 320-370 J/g and long-term storage stability (half-life of about 3 months). On this basis, we fabricate high-performance, flexible film devices of solar thermal battery, which can be readily recharged at room temperature with good cycling ability, show fast rate of heat release, and produce high-temperature heat that is >20<sup> o</sup>C higher than the ambient temperature. Our work opens up a new avenue to harvest ambient heat, and demonstrate a feasible strategy to develop high-performance solar thermal battery.

Efficient Co-Harvesting of Solar Energy and Low-Grade Heat by Molecular Photoswitches for High Energy Density, Long-Term Stable Solar Thermal Battery

2019 ◽  
Author(s):  
Zhao-Yang Zhang ◽  
Tao LI
Keyword(s):  
Energy Density ◽  
Solar Energy ◽  
High Performance ◽  
High Energy ◽  
Solar Thermal ◽  
High Energy Density ◽  
Low Grade ◽  
Thermal Battery ◽  
Low Grade Heat

Solar energy and ambient heat are two inexhaustible energy sources for addressing the global challenge of energy and sustainability. Solar thermal battery based on molecular switches that can store solar energy and release it as heat has recently attracted great interest, but its development is severely limited by both low energy density and short storage stability. On the other hand, the efficient recovery and upgrading of low-grade heat, especially that of the ambient heat, has been a great challenge. Here we report that solar energy and ambient heat can be simultaneously harvested and stored, which is enabled by room-temperature photochemical crystal-to-liquid transitions of small-molecule photoswitches. The two forms of energy are released together to produce high-temperature heat during the reverse photochemical phase change. This strategy, combined with molecular design, provides high energy density of 320-370 J/g and long-term storage stability (half-life of about 3 months). On this basis, we fabricate high-performance, flexible film devices of solar thermal battery, which can be readily recharged at room temperature with good cycling ability, show fast rate of heat release, and produce high-temperature heat that is >20<sup> o</sup>C higher than the ambient temperature. Our work opens up a new avenue to harvest ambient heat, and demonstrate a feasible strategy to develop high-performance solar thermal battery.

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