Evaluation of special communications-grade fibers in interferometric and microbend sensors for measurements with ambient temperature fluctuations

1993 ◽  
Author(s):  
Mardi C. Hastings ◽  
Bornain Chiu ◽  
Jeffrey D. Myers ◽  
Tzyy-Shuh Chang
Keyword(s):  
Ambient Temperature ◽  
Temperature Fluctuations

scholarly journals THERMODYNAMICS IN NESTS OF TWO MELIPONA SPECIES IN BRASIL

1983 ◽  
Vol 13 (2) ◽  
pp. 453-466 ◽  
Author(s):  
David W. Roubik ◽  
◽  
Francisco Javier Aquilera Peralta ◽  
Keyword(s):  
Ambient Temperature ◽  
Time Lag ◽  
Temperature Fluctuations ◽  
Nest Structure ◽  
Brood Chamber ◽  
Nest Cavity ◽  
Melipona Species ◽  
Brood Temperature ◽  
Average Brood ◽  
Brood Nest

SUMMARY Thermodynamics within 10 nests of Melipona rufiventris and M. seminigra were recorded during 48 horurs with thermocouple probes. Strikingly similar patterns were found for both species. Homeostasis did not occur; temperatures within the brood area, honey and pollen stored in pots and nest cavity space all followed ambient temperature fluctuations. Nest temperatures were consistently higher than ambient in all portions of the nest except the upper extremith of vertically elongate hives. Near the brood, temperature fluctuations were damped and displayed a time lag of one to two hours in following ambient temperature. The thoracic temperature of resting worker bees was near 34°C, and the average brood temperature was 31 — 32°. The involucrum surrounding the brood retained a portion of radiated heat from immatures and workers resting between combs, and brood temperature was two to three degrees higher than internal nest temperature immediately outside the involucrum. The brood chamber, the largest nest structure, contained from 2000 to 6000 immatures, and adult bee populations were less than 1000. The brood nest acts as a heat source at the base of the nest and dissipates heat upwards, creating a thermal gradient. Immature bees appear to supply most of the heat for the nest, and excess heat is shunted by fanning workers through the nest entrance, usually connected to the brood area. There is no evidence of evaporative cooling from water brought into the nest in these or other species of Meliponinae.

scholarly journals Birefringent Bragg Grating in C-Shaped Optical Fiber as a Temperature-Insensitive Refractometer

Sensors ◽  
2018 ◽  
Vol 18 (10) ◽  
pp. 3285 ◽  
Author(s):  
Rex Tan ◽  
Daryl Ho ◽  
Chun Tse ◽  
Yung Tan ◽  
Seong Yoo ◽  
...  
Keyword(s):  
Refractive Index ◽  
Optical Fiber ◽  
Ambient Temperature ◽  
Fiber Bragg Gratings ◽  
Temperature Fluctuations ◽  
Single Mode ◽  
Single Mode Fiber ◽  
Refractive Index Sensitivity ◽  
Index Sensitivity ◽  
Index Unit

We demonstrate a simple-to-fabricate refractometer based on the inscription of fiber Bragg gratings in a special C-shaped optical fiber. The C-shaped fiber was drawn into shape using a quarter cladding removed preform of a commercial standard single-mode fiber by simple machining. The sensor did not suffer from cross-sensitivity of the refractive index with ambient temperature fluctuations, commonly occurring with many optical fiber refractometers. A refractive index sensitivity of 1300 pm per refractive index unit (RIU) was achieved without employing any additional sensitization techniques such as tapering or etching.

scholarly journals Gut Microbiota and Host Thermoregulation in Response to Ambient Temperature Fluctuations

mSystems ◽  
2020 ◽  
Vol 5 (5) ◽  
Author(s):  
Saeid Khakisahneh ◽  
Xue-Ying Zhang ◽  
Zahra Nouri ◽  
De-Hua Wang
Keyword(s):  
Phenotypic Plasticity ◽  
Gut Microbiota ◽  
Ambient Temperature ◽  
Core Body Temperature ◽  
Energy Resource ◽  
Temperature Fluctuations ◽  
Temperature Acclimation ◽  
Metabolic Adaptation ◽  
Mongolian Gerbils ◽  
Metabolic Plasticity

ABSTRACT Ambient temperature (Ta) is an important factor in shaping phenotypic plasticity. Plasticity is generally beneficial for animals in adapting to their environments. Gut microbiota are crucial in regulating host physiological and behavioral processes. However, whether the gut microbiota play a role in regulating host phenotypic plasticity under the conditions of repeated fluctuations in environmental factors has rarely been examined. We used intermittent Ta acclimations to test the hypothesis that the plasticity of gut microbiota confers on the host a metabolic adaptation to Ta fluctuations. Mongolian gerbils (Meriones unguiculatus) were acclimated to intermittent 5°C to 23°C, 37°C to 23°C or 23°C to 23°C conditions for 3 cycles (totally 3 months). Intermittent Ta acclimations induced variations in resting metabolic rate (RMR), serum thyroid hormones, and core body temperature (Tb). We further identified that the β-diversity of the microbial community varied with Ta and showed diverse responses during the 3 cycles. Some specific bacteria were more sensitive to Ta and were associated with host dynamic metabolic plasticity during Ta acclimations. In addition, depletion of gut microbiota in antibiotic-treated gerbils impaired metabolic plasticity, particularly at low Ta, whereas supplementation with propionate as an energy resource improved the inhibited thermogenic capacity and increased the survival rate in the cold. These findings demonstrate that both gut microbiota and their host were more adaptive after repeated acclimations, and dynamic gut microbiota and their metabolites may confer host plasticity in thermoregulation in response to Ta fluctuations. It also implies that low Ta is a crucial cue in driving symbiosis between mammals and their gut microbiota during evolution. IMPORTANCE Whether gut microbiota play a role in regulating host phenotypic plasticity in small mammals living in seasonal environments has rarely been examined. The present study, through an intermittent temperature acclimation model, indicates that both gut microbiota and their host were more adaptive after repeated acclimations. It also demonstrates that dynamic gut microbiota confer host plasticity in thermoregulation in response to intermittent temperature fluctuations. Furthermore, low temperature seems to be a crucial cue in driving the symbiosis between mammals and their gut microbiota during evolution.

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