Regular oscillation in two-section laser structures based on δ-doped superlattices

2002 ◽  
Author(s):  
D.V. Ushakov ◽  
V.K. Kononenko ◽  
I.S. Manak
Keyword(s):  
Regular Oscillation

The growth of restricted populations of Lasioderma serricorne (F.) (Coleoptera, Anobiidae)

1964 ◽  
Vol 55 (1) ◽  
pp. 87-96 ◽  
Author(s):  
L. P. Lefkovitch
Keyword(s):  
Food Shortage ◽  
Population History ◽  
The Other ◽  
Initial Increase ◽  
Lasioderma Serricorne ◽  
Regular Oscillation ◽  
High Level

Two types of population history shown by Lasioderma serricorne (F.) are described, one when the food was renewed at regular intervals, the other when there was no food renewal. Initially, both of these populations increased together to a high level, the former continuing at this level until the observations were discontinued, the latter declining and eventually becoming extinct. Stage-specific properties, which relate the numbers in each stage to those a unit of time previously and which are functions of the survival, developmental and fecundity rates, were estimated for each type of population; they are compared as between the two types and with the corresponding properties of a population given effectively unlimited space and food. It is shown that the effect of the limiting conditions produced a decrease in survival, developmental and fecundity rates. From this, together with other evidence, it appears that food shortage, not space shortage, was the primary cause. After the initial increase in numbers, the stage-specific properties shown by the species in both populations imply that there was a regular oscillation in the developmental, survival or fecundity rates, which would result in corresponding fluctuations in numbers.

scholarly journals Mapping circuit dynamics during function and dysfunction

2021 ◽  
Author(s):  
Srinivas Gorur-Shandilya ◽  
Elizabeth M Cronin ◽  
Anna C Schneider ◽  
Sara Ann Haddad ◽  
Philipp Rosenbaum ◽  
...  
Keyword(s):  
Collective Behavior ◽  
Neural Circuits ◽  
Neural Circuit ◽  
Disease States ◽  
Environmental Perturbations ◽  
Functional Dynamics ◽  
Unsupervised Approach ◽  
Regular Oscillation ◽  
Spike Patterns ◽  
Phase Relationships

Neural circuits can generate many spike patterns, but only some are functional. The study of how circuits generate and maintain functional dynamics is hindered by a poverty of description of circuit dynamics across functional and dysfunctional states. For example, although the regular oscillation of a central pattern generator is well characterized by its frequency and the phase relationships between its neurons, these metrics are ineffective descriptors of the irregular and aperiodic dynamics that circuits can generate under perturbation or in disease states. By recording the circuit dynamics of the well-studied pyloric circuit in C. borealis, we used statistical features of spike times from neurons in the circuit to visualize the spike patterns generated by this circuit under a variety of conditions. This unsupervised approach captures both the variability of functional rhythms and the diversity of atypical dynamics in a single map. Clusters in the map identify qualitatively different spike patterns hinting at different dynamical states in the circuit. State probability and the statistics of the transitions between states varied with environmental perturbations, removal of descending neuromodulation, and the addition of exogenous neuromodulators. This analysis reveals strong mechanistically interpretable links between complex changes in the collective behavior of a neural circuit and specific experimental manipulations, and can constrain hypotheses of how circuits generate functional dynamics despite variability in circuit architecture and environmental perturbations.

scholarly journals Moonlight controls lunar-phase-dependency and regular oscillation of clock gene expressions in a lunar-synchronized spawner fish, Goldlined spinefoot

2018 ◽  
Vol 8 (1) ◽  
Author(s):  
Yuki Takeuchi ◽  
Ryo Kabutomori ◽  
Chihiro Yamauchi ◽  
Hitomi Miyagi ◽  
Akihiro Takemura ◽  
...  
Keyword(s):  
Clock Gene ◽  
Lunar Phase ◽  
Gene Expressions ◽  
Regular Oscillation

The regular-oscillation state in a ruby laser

1970 ◽  
Vol 13 (5) ◽  
pp. 1529-1531
Author(s):  
T. I. Tiunova ◽  
A. M. Ratner
Keyword(s):  
Ruby Laser ◽  
Regular Oscillation

Food intake, growth and mature size in Australian Merino and Dorset horn sheep

1983 ◽  
Vol 36 (3) ◽  
pp. 471-479 ◽  
Author(s):  
J. M. Thompson ◽  
J. R. Parks
Keyword(s):  
Food Intake ◽  
Annual Cycle ◽  
Live Weight ◽  
Food Efficiency ◽  
Regular Oscillation ◽  
Ad Libitum ◽  
Mature Size ◽  
Food Consumed ◽  
Australian Merino

ABSTRACTThe pattern of food intake as a function of age, and live weight as a function of food consumed was examined from soon after weaning to maturity in groups of fine and strong wool Merino rams and Dorset Horn rams and wethers. Each group, which initially comprised 20 sheep and from which individuals were removed for slaughter at approximately 6-kg increments in live weight, was fed a pelleted ration ad libitum for 98 and 77 weeks for the Merino and Dorset Horn groups respectively.The pattern of food intake was similar for all groups of sheep, in that food intake increased to a maximum at approximately 50 weeks of age and then declined with age with a regular oscillation superimposed on this curve. In all three groups of rams, but not in the Dorset Horn wethers, the oscillations in food intake were on an approximate annual cycle with a decrease in food intake in summer and an increase in winter.Estimated mature live weights for the strong and fine wool Merino rams were 120·5 and 97·6 kg, and for the Dorset Horn rams and wethers 108·6 and 101·4 kg. Variation between breeds in the level of food intake, food efficiency and consequently the pattern of growth, was largely a function of mature size. The Dorset Horn rams were slightly more efficient at converting food to live weight than the wethers.

scholarly journals Regular oscillation sub-spectrum of rapidly rotating stars

2012 ◽  
Vol 546 ◽  
pp. A11 ◽  
Author(s):  
M. Pasek ◽  
F. Lignières ◽  
B. Georgeot ◽  
D. R. Reese
Keyword(s):  
Rotating Stars ◽  
Regular Oscillation ◽  
Rapidly Rotating Stars

Food intake, growth and body composition in Australian Merino sheep selected for high and low weaning weight. 1. Food intake, food efficiency and growth

1985 ◽  
Vol 40 (1) ◽  
pp. 55-70 ◽  
Author(s):  
J. M. Thompson ◽  
J. R. Parks ◽  
Diana Perry
Keyword(s):  
Body Weight ◽  
Food Intake ◽  
Conversion Efficiency ◽  
Growth Curves ◽  
Growth Efficiency ◽  
Food Conversion ◽  
Weaning Weight ◽  
Regular Oscillation ◽  
Selection For ◽  
Food Conversion Efficiency

ABSTRACTChanges in the pattern of food intake, food conversion efficiency and growth from weaning to maturity, were examined in 35 rams and ewes from flocks of Merino sheep selected for high (weight-plus) and low (weight-minus) weaning weight and from a randomly bred control flock. The sheep were individually fed a pelleted ration ad libitum for at least 72 weeks and up to 90 weeks post weaning. Weekly food intake was described as an increasing exponential function of age with a linearly declining asymptote, about which a regular oscillation occurred, and weekly body-weight gain was described as an increasing exponential function of weekly food intake, about which a regular oscillation also occurred.The oscillations in weekly food intake had a period of about 52 weeks and appeared to be largely associated with seasonal variations in temperature, with an increased food intake during winter and a decreased food intake during summer. The oscillations in both the food-intake and body-weight functions were of similar phase and period and it was suggested that the body-weight oscillations were due to variation in gut-fill, a result of the seasonal oscillations in food intake.Selection for weaning weight changed the shape and magnitude of the food-intake curve, with the weight-plus having a greater rate of food intake (i.e. appetite) in the early stages of growth and a greater asymptote than the weight-minus animals. Selection for high and low weaning weight also resulted in an increase and a decrease in mature weight. Both strains had a similar growth efficiency, although when calculated as gross food conversion efficiency the weight-plus were higher than the weight-minus animals at the same body weight, whereas there was no difference between strains at the same age.The rams had both a higher asymptote and a slower rate of decline in food intake than the ewes. Rams had a higher mature weight than the ewes, although ewes had a slightly greater growth efficiency. However, when calculated as gross food conversion efficiency, ewes tended to be lower than rams, when compared either at the same age, or at the same body weight.When the food-intake curves were standardized for differences in mature size, strain differences in the magnitude of the food-intake curves were reduced, although differences in the shape were still apparent. Shape differences in the food-intake curves were reflected in the shape of the standardized growth curves, with the weight-plus maturing at a faster rate than the weight-minus animals. There was little difference between the sexes in the initial shape of the food-intake curve, although at later ages ewes had a lower food intake than rams. There was little difference between the sexes in the shape of the standardized growth curves.

Some statistical properties of random noise

1949 ◽  
Vol 45 (3) ◽  
pp. 368-372 ◽  
Author(s):  
D. K. C. MacDonald
Keyword(s):  
Experimental Investigation ◽  
Correlation Function ◽  
Power Spectrum ◽  
Narrow Range ◽  
Random Noise ◽  
Practical Importance ◽  
Statistical Properties ◽  
Regular Oscillation ◽  
Image Position ◽  
Random Fluctuations

A considerable volume of knowledge is now available on random fluctuations (noise) as regards the behaviour in amplitude. Familiar names in this field are those of Uhlenbeck and Ornstein(7), Fürth(1) and Rice (4), although very many others have made valuable contributions. A particular class of problem, of considerable practical importance, exists when the frequency spectrum is limited to a relatively narrow range. The resulting noise has then the character of a more or less regular oscillation modulated randomly in amplitude and phase. In this case, if we write the fluctuation in the form(where R(t) and θ(t) are variables changing slowly in comparison with sinω0t), it is clear that the magnitude of the envelope R(t) and the phase θ(t) are now the significant quantities. Rice (4), among others, has made a study of the statistical properties of R, deriving in particular the correlation function R(t) R(t + τ) in terms of the characteristics of the (power) spectrum ω(f). Fürth and the writer (2) have extended this work and carried out a collateral experimental investigation.

Features of the Operation of Powered Resonance Tube Actuators: Experiments and Simulations

2003 ◽  
Author(s):  
Ganesh Raman ◽  
Shekhar Sarpotdar ◽  
Alan B. Cain
Keyword(s):  
Flow Control ◽  
Active Flow Control ◽  
Reynolds Numbers ◽  
Detailed Characterization ◽  
Low Reynolds Numbers ◽  
Resonance Tube ◽  
Upstream Direction ◽  
Regular Oscillation ◽  
Active Flow

There has been a recent surge of interest in powered resonance tube actuators for flow control applications. Additional features of powered resonance tube actuators (both experiments and simulations) are presented in this paper. A Powered Resonance Tube (PRT) is a device based on aeroacoustics principles, capable of producing intense perturbation levels for use in active flow control. The PRT described here is capable of producing frequencies ranging from 1600 to 15,000 Hz at amplitudes as high as 160 dB near the source. Our detailed experiments aimed at understanding the PRT phenomenon are complemented by improved direct numerical simulations. We provide a detailed characterization of the unsteady pressures in the nearfield of the actuator using phase averaged pressure measurements. The measurements revealed that propagating fluctuations were biased towards the upstream direction (relative to the supply jet) for some frequencies. However, this feature depended on the frequency at which the device was operated. The simulations that were performed earlier at a Reynolds number 490 times lower than that in the experiment have been refined. The current simulations are performed at 49 times lower than that in the experiments and show that a finer scale structure develops at higher Reynolds numbers and a more regular oscillation is present at low Reynolds numbers.

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