Adaptation as a Mechanism for Gain Control in an Insect Thermoreceptor

2008 ◽  
Vol 100 (4) ◽  
pp. 2137-2144 ◽  
Author(s):  
Harald Tichy ◽  
Harald Fischer ◽  
Ewald Gingl
Keyword(s):  
Temperature Change ◽  
Thermal Effects ◽  
Gain Control ◽  
Input Function ◽  
High Gain ◽  
Oscillation Period ◽  
Rate Of Change ◽  
Temperature Changes ◽  
Precise Information ◽  
Instantaneous Temperature

Adaptation controls the gain of the input-function of the cockroach's cold cell during slowly oscillating changes in temperature. When the oscillation period is long, the cold cell improves its gain for the rate of temperature change at the expense of its ability to code instantaneous temperature. When the oscillation period is brief, however, the cold cell reduces this gain and improves its sensitivity for instantaneous temperature. This type of gain control has an important function. When the cockroach ventures from under cover and into moving air, the cold cell is confronted constantly with brief changes in temperature. To be of any use, a limit in the gain for the rate of change seems to be essential. Without such a limit, the cold cell will always indicate temperature change. The decrease in gain for the rate of change involves an increase in gain for instantaneous temperature. Therefore the animal receives precise information about the temperature at which the change occurs and can seek an area of different temperature. If the cockroach ventures back under cover, the rate of change will become slow. In this situation, a high gain improves the ability to signal slow temperature changes. The cockroach receives the early warning of slow fluctuations or even creeping changes in temperature. A comparison of the cold cell's responses with the temperature measured inside of small, cylindrical model objects indicates that coding characteristic rather than passive thermal effects of the structures enclosing the cold cell are responsible for the observed behavior.

scholarly journals The Thermal Sensitivity of the Lateralis Organs of Xenopus

1956 ◽  
Vol 33 (4) ◽  
pp. 798-805
Author(s):  
R. W. MURRAY
Keyword(s):  
Xenopus Laevis ◽  
Temperature Change ◽  
Time Constant ◽  
Mechanical Stimulation ◽  
Thermal Sensitivity ◽  
Rate Of Change ◽  
Sensory Cells ◽  
Temperature Changes ◽  
Steady Level ◽  
Opposite Response

1. A convenient isolated preparation of the lateralis organs and nerve of Xenopus laevis is described. An average of two active units can be obtained by cutting between the groups of organs in the skin. 2. There is a basic discharge, which is irregular and which varies directly with steady temperatures. 3. An opposite response is obtained to temperature changes. On cooling there is an increase in frequency adapting to the new steady level with a time-constant of 20 sec., and on warming there is a corresponding decrease in frequency. 4. The threshold for temperature change is 1-2° C., representing a rate of change of temperature of 0.3-0.6° C./sec. at the surface of the skin. 5. In the more sensitive preparations the basic frequency is doubled or completely inhibited by a change of 5° C. 6. The threshold change of temperature for similar preparations of skin and segmental cutaneous nerve is 5-10° C. 7. The discharge frequency can be increased by mechanical stimulation, but only at intensities high enough to act at the nerve endings directly and not by way of the sensory cells. The sensitivity is comparable to that of the segmental cutaneous nerves.

A walking bout reveals altered foot thermodynamics associated with unilateral transtibial amputation among individuals with type 2 diabetes

2020 ◽  
pp. 030936462096864
Author(s):  
Kyle R Leister ◽  
Shane R Wurdeman
Keyword(s):  
Type 2 Diabetes ◽  
Temperature Change ◽  
Foot Ulcer ◽  
Diabetic Foot Ulcer ◽  
Rate Of Change ◽  
Peak Temperature ◽  
Cross Sectional ◽  
Contralateral Limb ◽  
Transtibial Amputation

Background: Increased foot temperature among individuals with type 2 diabetes can be predictive of diabetic foot ulcer development. A combination of physiological and mechanical deficiencies may contribute to elevations in intact foot temperature during gait for individuals with type 2 diabetes and transtibial amputation. Objective: This study evaluated plantar foot temperature differences between individuals with type 2 diabetes with and without transtibial amputation. We hypothesized that individuals with transtibial amputation maintain increased foot temperature compared to those without amputation. Study Design: Cross-sectional, case control. Methods: A sample of 16 participants with type 2 diabetes and transtibial amputation, and 16 age- and sex-matched participants with type 2 diabetes without amputation were recruited. Foot temperatures were measured during resting, walking, and cooldown periods. Peak temperature, mean temperature, and rate of temperature change were analyzed for each period, and compared between cohorts. Results: Participants with amputation exhibited increased mean foot temperature while at rest and during walking. Participants without amputation exhibited increased rate of change of foot temperature during walking. No differences in peak temperature or rate of temperature change were observed during the baseline or cooldown periods. Conclusion: The current findings of altered foot temperature for individuals with transtibial amputation and type 2 diabetes suggest a possible reason for the high rates of contralateral limb ulceration and amputation among this population.

scholarly journals SIMULATION AND EXPERIMENT OF EXTINCTION OR ADAPTATION OF BIOLOGICAL SPECIES AFTER TEMPERATURE CHANGES

2005 ◽  
Vol 16 (03) ◽  
pp. 389-392 ◽  
Author(s):  
D. STAUFFER ◽  
H. ARNDT
Keyword(s):  
Sexual Reproduction ◽  
Temperature Change ◽  
Biological Species ◽  
Biological Aging ◽  
Heterotrophic Flagellates ◽  
Temperature Changes ◽  
Penna Model ◽  
Simulation And Experiment ◽  
Unicellular Organisms

Can unicellular organisms survive a drastic temperature change, and adapt to it after many generations? In simulations of the Penna model of biological aging, both extinction and adaptation were found for asexual and sexual reproduction as well as for parasex. These model investigations are the basis for the design of evolution experiments with heterotrophic flagellates.

On the Practical Stability of Incorporating Integral Compensation Into the Low-and-High Gain Control for a Class of Systems With Norm-Type Input Saturation

2008 ◽  
Vol 130 (3) ◽  
Author(s):  
Shou-Tao Peng
Keyword(s):  
Input Saturation ◽  
Gain Control ◽  
High Gain ◽  
Output Regulation ◽  
Practical Stability ◽  
Design Parameters ◽  
Linear Matrix ◽  
Control Input ◽  
Chattering Effect ◽  
Practical Stabilization

This paper studies the practical stability of incorporating integral compensation into the original low-and-high gain feedback law. The motivation for the incorporation is for achieving output regulation in the presence of constant disturbances without the use of a very large high-gain parameter required in the original approach. Due to numerical accuracy, the employment of very large high-gain parameters to eliminate steady-state error has the potential for inducing undesirable chattering effect on the control signal. A set of linear matrix inequalities is formulated in this study to obtain the related design parameters, by which the incorporation can achieve both the practical stabilization and asymptotic output regulation in the presence of input saturation and constant disturbances. Furthermore, the saturation of the control input can be shown to vanish in finite time during the process of regulation. Numerical examples are given to demonstrate the effectiveness of the proposed approach.

scholarly journals High-gain control without identification: a survey

2008 ◽  
Vol 31 (1) ◽  
pp. 115-125 ◽  
Author(s):  
Achim Ilchmann ◽  
Eugene P. Ryan
Keyword(s):  
Gain Control ◽  
High Gain ◽  
High Gain Control

Measurement of pelvic blood flow changes in response to posture in normal subjects and in women with pelvic pain owing to congestion by using a thermal technique

1992 ◽  
Vol 83 (1) ◽  
pp. 55-58 ◽  
Author(s):  
D. C. Thomas ◽  
R. W. Stones ◽  
C. M. Farquhar ◽  
R. W. Beard
Keyword(s):  
Blood Flow ◽  
Pelvic Pain ◽  
Normal Subjects ◽  
Rate Of Change ◽  
Venous Congestion ◽  
Axillary Temperature ◽  
Temperature Changes ◽  
Thermal Technique ◽  
Vaginal Temperature ◽  
Pelvic Blood Flow

1. A method is described for studying pelvic blood flow in women by the indirect method of measuring vaginal temperature changes in response to a posture change. Ten women with chronic pelvic pain and venous congestion and 10 normal subjects were observed during posture changes over a 2 h period. 2. Vaginal temperature minus axillary temperature rose after subjects changed from the supine to the seated position, indicating a fall in the rate of pelvic blood flow. 3. A significantly greater variance in the rate of change in vaginal temperature minus axillary temperature was found in patients with pelvic venous congestion compared with control subjects (P> 0.005). 4. The findings are consistent with a disorder of blood flow regulation in women with pelvic pain owing to congestion.

10 Gb/s Burst-Mode Transimpedance Preamplifier in 0.13µm CMOS Technology

2012 ◽  
Vol 241-244 ◽  
pp. 2215-2220
Author(s):  
Gao Wei Gu ◽  
En Zhu
Keyword(s):  
Gain Control ◽  
Cmos Technology ◽  
Fast Response ◽  
High Gain ◽  
Settling Time ◽  
Output Buffer ◽  
Peak Detector ◽  
Burst Mode ◽  
Variable Gain ◽  
Response Peak

A 10Gbit/s burst-mode transimpedance preamplifier is described. Regulated cascade (RGC) TIA core with variable gain, fast response peak detector, single-to-differential and output buffer are included, providing auto-gain-control and threshold extraction functions. The burst-mode preamplifier is implemented by 0.13µm CMOS technology, presents a high gain of 67.9dB with a 3-dB bandwidth of 6.92GHz and a low gain of 57.4dB with a 3-dB bandwidth of 8.60GHz with a settling time less than 20ns.

346. Measurements of the rate of change of temperature in high temperature-short time pasteurization plant

1947 ◽  
Vol 15 (1-2) ◽  
pp. 18-23
Author(s):  
F. Steghart
Keyword(s):  
High Temperature ◽  
Time Constant ◽  
Rate Of Change ◽  
Hot Water ◽  
Water Pipe ◽  
Temperature Changes ◽  
Rates Of Change ◽  
High Temperature Short Time ◽  
Short Time

It has recently been claimed that in modern high temperature-short time pasteurization plant fluctuations in temperature of the order of 1° F./sec. are unusual and probably artefacts, and that an instantaneous drop is certainly fictitious.It has, nevertheless, been shown that such rapid drops in temperature do in fact occur frequently in high temperature-short time plants of the type investigated. The plant investigated was not of the latest design incorporating devices for speeding up the control by injecting steam directly into the hot-water pipe.Temperature changes of the order of those in question were first observed by Mattick & Hiscox(1) of the National Institute for Research in Dairying, who carried out tests on pasteurization plant using a small mirror galvanometer with a very short time constant. The maximum rates of change were, however, not observed.

Data-driven analysis on thermal effects and temperature changes of lithium-ion battery

2021 ◽  
Vol 482 ◽  
pp. 228983
Author(s):  
Shan Zhu ◽  
Chunnian He ◽  
Naiqin Zhao ◽  
Junwei Sha
Keyword(s):  
Lithium Ion Battery ◽  
Thermal Effects ◽  
Lithium Ion ◽  
Data Driven ◽  
Temperature Changes

Continuous Tonic Spike Activity in Spider Warm Cells in the Absence of Sensory Input

2006 ◽  
Vol 96 (3) ◽  
pp. 989-997 ◽  
Author(s):  
E. Gingl ◽  
H. Tichy
Keyword(s):  
Electrical Stimulation ◽  
Sensory Input ◽  
Discharge Rate ◽  
Rate Of Change ◽  
Intrinsic Properties ◽  
Response Curves ◽  
Temperature Changes ◽  
Different Temperatures ◽  
Low Amplitude ◽  
The Relationship

The warm cells of the spider tarsal organ respond very sensitively to low-amplitude changes in temperature and discharge continuously as the rate of change in temperature reaches zero. To test whether the continuous tonic discharge remains without sensory input, we blocked the warm cell's receptive region by Epoxy glue. The activity continued in this situation, but its dependence on temperature changes was strongly reduced. We interpret this to mean that the warm cells exhibit specific intrinsic properties that underlie the generation of the tonic discharge. Experiments with electrical stimulation confirmed the observation that the warm cells persist in activity without an external drive. In warm cells with blocked receptive region, the response curves describing the relationship between the tonic discharge and the level of depolarization is the same for different temperatures. In warm cells with intact receptive region, the curves are shifted upward with rising temperature, as if the injected current is simply added to the receptor current. This indicates a modulating effect of the receptor current on the tonic discharge. Stimulation causes a change in the tonic discharge rate and thereby enables individual warm cells to signal the direction in addition to the magnitude of temperature changes.

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