scholarly journals A physical explanation of solar microwave Zebra pattern with the current-carrying plasma loop model

2009 ◽  
Vol 325 (2) ◽  
pp. 251-257 ◽  
Author(s):  
Baolin Tan
Keyword(s):  
Loop Model ◽  
Physical Explanation ◽  
Zebra Pattern ◽  
Solar Microwave ◽  
Plasma Loop

scholarly journals Microwave Burst Timescales and Solar Flare Acceleration Processes

1994 ◽  
Vol 142 ◽  
pp. 683-688
Author(s):  
A. Krüger ◽  
B. Kliem ◽  
J. Hildebrandt ◽  
V. V. Zaitsev
Keyword(s):  
Electric Circuit ◽  
Magnetic Loop ◽  
Circuit Model ◽  
Simultaneous Occurrence ◽  
Loop Model ◽  
Coalescence Model ◽  
Solar Microwave ◽  
Fine Structures ◽  
Time Structures ◽  
Front Model

AbstractThe occurrence of quite different timescales in solar microwave bursts is considered and possible ways of their physical interpretation are discussed. An interesting feature is the existence of hierarchic time structures, an example of which is provided by the solar event of 1991 March 23.Plasma parameter sets to be invoked for the interpretation of timescales are estimated on the base of different models such as the collisionless conduction front model, the twisted magnetic loop model, the coalescence model, and the electric circuit model. With emphasis on the interpretation of burst fine structures with timescales of a few seconds the coalescence model has been favored. On the other hand, the simultaneous occurrence of a large range of different timescales appears well suited to be described by the circuit model.Subject headings: acceleration of particles — Sun: flares — Sun: radio radiation

Inhibition of Fibrinolytic Activity In-Vivo by Dexamethasone Is Counterbalanced by an Inhibition of Platelet Aggregation

1992 ◽  
Vol 68 (01) ◽  
pp. 069-073 ◽  
Author(s):  
J J J van Giezen ◽  
J W C M Jansen
Keyword(s):  
Platelet Aggregation ◽  
Fibrinolytic Activity ◽  
Ex Vivo ◽  
Dose Range ◽  
Coagulation System ◽  
Loop Model ◽  
Prothrombotic State ◽  
Inhibition Of Platelet Aggregation ◽  
Pai 1

SummaryDexamethasone decreases the fibrinolytic activity in cultured medium of several cell types by an induction of PAI-1 synthesis. As a result of this enhanced PAI-1 synthesis a prothrombotic state is expected in patients treated with dexamethasone. However, such a prothrombotic state is not reported as a major adverse effect. We have studied the effects of dexamethasone (dose range: 0.1–3.0 mg/kg) on the fibrinolytic system of rats after a 5 day pretreatment period. It appeared that dexamethasone dose dependently decreased the fibrinolytic activity (a dose of 1 mg/kg showed a reduction of about 40%). This reduced fibrinolytic activity could be functionally translated into an increased thrombus size as measured with a venous thrombosis model: thrombus size was increased by 50% with 1 mg/kg dexamethasone. No effects could be measured on the coagulation system, but it appeared that ex-vivo measured platelet aggregation was dose dependently inhibited by dexamethasone treatment. This effect resulted in-vivo in prolonged obstruction times as measured with a modified aorta-loop model. These results indicate that the expected prothrombotic state due to a diminished fibrinolytic activity caused by dexamethasone is counterbalanced by an inhibition of platelet aggregation.

The Metabolic Theory of Ecology

2017 ◽  
Author(s):  
Andrew Clarke
Keyword(s):  
Metabolic Rate ◽  
Resting Metabolic Rate ◽  
Effect Of Temperature ◽  
Thermal Ecology ◽  
Model Data ◽  
Metabolic Theory ◽  
Physical Explanation ◽  
Boltzmann Factor ◽  
Scaling Exponents ◽  
Metabolic Theory Of Ecology

The model of West, Brown & Enquist (WBE) is built on the assumption that the metabolic rate of cells is determined by the architecture of the vascular network that supplies them with oxygen and nutrients. For a fractal-like network, and assuming that evolution has minimised cardiovascular costs, the WBE model predicts that s=metabolism should scale with mass with an exponent, b, of 0.75 at infinite size, and ~ 0.8 at realistic larger sizes. Scaling exponents ~ 0.75 for standard or resting metabolic rate are observed widely, but far from universally, including in some invertebrates with cardiovascular systems very different from that assumed in the WBE model. Data for field metabolic rate in vertebrates typically exhibit b ~ 0.8, which matches the WBE prediction. Addition of a simple Boltzmann factor to capture the effects of body temperature on metabolic rate yields the central equation of the Metabolic Theory of Ecology (MTE). The MTE has become an important strand in ecology, and the WBE model is the most widely accepted physical explanation for the scaling of metabolic rate with body mass. Capturing the effect of temperature through a Boltzmann factor is a useful statistical description but too simple to qualify as a complete physical theory of thermal ecology.

scholarly journals Continuous Control Set Predictive Current Control for Induction Machine

2021 ◽  
Vol 11 (13) ◽  
pp. 6230
Author(s):  
Toni Varga ◽  
Tin Benšić ◽  
Vedrana Jerković Štil ◽  
Marinko Barukčić
Keyword(s):  
Control Method ◽  
Induction Machine ◽  
Current Control ◽  
Continuous Control ◽  
Loop Model ◽  
Voltage Reference ◽  
Control Loop ◽  
Speed Tracking ◽  
Finite Control ◽  
Control Set

A speed tracking control method for induction machine is shown in this paper. The method consists of outer speed control loop and inner current control loop. Model predictive current control method without the need for calculation of the weighing factors is utilized for the inner control loop, which generates a continuous set of voltage reference values that can be modulated and applied by the inverter to the induction machine. Interesting parallels are drawn between the developed method and state feedback principles that helped with the analysis of the stability and controllability. Simple speed and rotor flux estimator is implemented that helps achieve sensorless control. Simulation is conducted and the method shows great performance for speed tracking in a steady state, and during transients as well. Additionally, compared to the finite control set predictive current control, it shows less harmonic content in the generated torque on the rotor shaft.

scholarly journals Visual Appearance of Oil on the Sea

2021 ◽  
Vol 9 (1) ◽  
pp. 97
Author(s):  
Merv Fingas
Keyword(s):  
Water Surface ◽  
Oil Spills ◽  
Discharge Rate ◽  
Physical Explanation ◽  
Visual Appearance ◽  
Oil In Water ◽  
Other Information ◽  
Surface Discharges ◽  
Oil Emulsions ◽  
Spilled Oil

The visual appearance of oil spills at sea is often used as an indicator of spilled oil properties, state and slick thickness. These appearances and the oil properties that are associated with them are reviewed in this paper. The appearance of oil spills is an estimator of thickness of thin oil slicks, thinner than a rainbow sheen (<3 µm). Rainbow sheens have a strong physical explanation. Thicker oil slicks (e.g., >3 µm) are not correlated with a given oil appearance. At one time, the appearance of surface discharges from ships was thought to be correlated with discharge rate and vessel speed; however, this approach is now known to be incorrect. Oil on the sea can sometimes form water-in-oil emulsions, dependent on the properties of the oil, and these are often reddish in color. These can be detected visually, providing useful information on the state of the oil. Oil-in-water emulsions can be seen as a coffee-colored cloud below the water surface. Other information gleaned from the oil appearance includes coverage and distribution on the surface.

scholarly journals Quasiclassical calculations of Landau level spectrum for 20.5-nm-wide H gTe quantum well: “extremum loop” model and effects of cubic symmetry

2021 ◽  
Vol 47 (1) ◽  
pp. 7-13
Author(s):  
S. V. Gudina ◽  
A. S. Bogolubskiy ◽  
V. N. Neverov ◽  
K. V. Turutkin ◽  
N. G. Shelushinina ◽  
...  
Keyword(s):  
Quantum Well ◽  
Landau Level ◽  
Loop Model ◽  
Cubic Symmetry ◽  
Level Spectrum

A Fast and Accurate True Event-driven Phase Locked Loop Model

2020 ◽  
Author(s):  
Christoph Beyerstedt ◽  
Jonas Meier ◽  
Fabian Speicher ◽  
Markus Scholl ◽  
Daniel Blase ◽  
...  
Keyword(s):  
Phase Locked Loop ◽  
Loop Model ◽  
Event Driven

scholarly journals Assembly of Two Transgenes in an Artificial Chromatin Domain Gives Highly Coordinated Expression in Tobacco

Genetics ◽  
2002 ◽  
Vol 160 (2) ◽  
pp. 727-740
Author(s):  
Ludmila Mlynárová ◽  
Annelies Loonen ◽  
Elzbieta Mietkiewska ◽  
Ritsert C Jansen ◽  
Jan-Peter Nap
Keyword(s):  
Enzyme Activities ◽  
Firefly Luciferase ◽  
Chromatin Domain ◽  
Mrna Levels ◽  
Loop Model ◽  
Data Generation ◽  
Genome Data ◽  
The Matrix ◽  
Coordinated Expression ◽  
Firefly Luciferase Gene

Abstract The chromatin loop model predicts that genes within the same chromatin domain exhibit coordinated regulation. We here present the first direct experimental support for this model in plants. Two reporter genes, the E. coli β-glucuronidase gene and the firefly luciferase gene, driven by different promoters, were placed between copies of the chicken lysozyme A element, a member of the matrix-associated region (MAR) group of chromatin boundary elements, and introduced in tobacco (Nicotiana tabacum). In plants carrying A elements, quantitative enzyme activities and mRNA levels of both genes show high correlations compared to control plants. The A element thus creates an artificial chromatin domain that yields coordinated expression. Surprisingly, enzyme activities correlated poorly with their respective mRNA levels. We hypothesize that this indicates the occurrence of “error pipelines” in data generation: systematic errors of a given analytical method will point in the same direction and cancel out in correlation analysis, resulting in better correlations. In combining different methods of analysis, however, such errors do not cancel out and as a result relevant correlations can be masked. Such error pipelines will have to be taken into account when different types of (e.g., whole-genome) data sets are combined in quantitative analyses.

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