scholarly journals The Evolution of Chemical Alarm Signals: Attracting Predators Benefits Alarm Signal Senders

1996 ◽  
Vol 148 (4) ◽  
pp. 649-659 ◽  
Author(s):  
Douglas P. Chivers ◽  
Grant E. Brown
Keyword(s):  
Alarm Signal ◽  
Alarm Signals ◽  
Chemical Alarm Signals

Intraspecific and Cross-Superorder Responses to Chemical Alarm Signals by Brook Stickleback

Ecology ◽  
1993 ◽  
Vol 74 (8) ◽  
pp. 2395-2404 ◽  
Author(s):  
Alicia Mathis ◽  
R. Jan F. Smith
Keyword(s):  
Alarm Signals ◽  
Chemical Alarm Signals ◽  
Brook Stickleback

scholarly journals Testing of Auditory Clinical Alarms in ICU/CCU

2020 ◽  
Vol 2 ◽  
pp. 9-17
Author(s):  
Thangavelu S. D. ◽  
Supriyanto E. ◽  
Yunus J.
Keyword(s):  
Test Signal ◽  
Alarm System ◽  
Alarm Signal ◽  
Single Tone ◽  
Alarm Signals ◽  
Clinical Alarms ◽  
Usability Tests ◽  
Sample Proportion ◽  
The One ◽  
Almost All

Almost all medical devices in ICU/CCU have a built-in clinical alarm system to alert when there are changes in a patient’s condition. The objective of this study is to investigate the effectiveness of the existing alarm system in ICU/CCU. Two summative usability tests were conducted to test the effectiveness of existing and new alarm signals based on IEC 60601-1-8:2006 standard. Further formative test is conducted to study the perception of urgency associated with a number of tones in the alarm signals. The findings indicate that the existing auditory alarm signal in ICU/CCU does not indicate the urgency of the alarm conditions. The simulation test indicates that the respondents preferred 282Hz, 500Hz and 800Hz for low, medium and high-risk alarm respectively. The one-sample proportion z test on urgency mapping indicates that the proportion of responses for the highest risk is more than 50% for a single tone test signal. These results show that a single tone test signal being perceived as the highest risk is regardless of frequency. It can be concluded the auditory alarm designed based on this IEC 60608-1-8:2006 standard is not effective. As such it is proposed that the incorporation of the new alarm frequencies and tones will improve the effectiveness of the alarm signal

scholarly journals Chemical alarm signals in wild Trinidadian guppies (Poecilia reticulata)

1999 ◽  
Vol 77 (4) ◽  
pp. 562-570 ◽  
Author(s):  
Grant E Brown ◽  
Jean-Guy J Godin
Keyword(s):  
Poecilia Reticulata ◽  
Alarm Pheromone ◽  
Field Experiments ◽  
Antipredator Behaviour ◽  
Skin Extract ◽  
Distilled Water ◽  
Alarm Signals ◽  
Alarm Pheromones ◽  
Chemical Alarm Signals ◽  
High Predation

We investigated the presence and possible function of chemical alarm signals (alarm pheromones) in wild Trinidadian guppies (Poecilia reticulata) using laboratory, trapping, and direct field observational methods. In laboratory experiments, female guppies from a population exposed to high predation significantly increased their shoaling, dashing, and freezing behaviours and significantly reduced area use when exposed to the skin extract of sympatric female guppies. When exposed to the skin extract of females from a low-predation population, female guppies from a high-predation population exhibited significant, though smaller, increases in antipredator behaviour. No significant differences in antipredator behaviours were noted when females were exposed to swordtail (Xiphophorus helleri) skin extract, which lacks any known alarm pheromone. We conducted two field experiments to confirm these laboratory results. In a trapping experiment, significantly more guppies were caught in funnel traps labelled with distilled water than in paired traps labelled with sympatric guppy skin extract. In a final experiment, a realistic model of a natural predator (pike cichlid, Crenicichla alta), paired with either sympatric guppy skin extract or distilled water, was presented to groups of free-ranging guppies in pools of a high-predation river. Significantly fewer guppies were observed within a 50-cm radius of the predator model and significantly fewer guppies inspected the model when it was paired with guppy skin extract versus distilled water. Taken together, our results strongly suggest the presence of a chemical alarm signal (alarm pheromone) in the Trinidadian guppy, establish the validity of laboratory and trapping studies in the investigation of chemical alarm signalling, and demonstrate that alarm pheromones may function to mediate predation risk under natural conditions in the guppy.

Correlation between measurement of an ice detector and the mass of ice accreted on two different sized conductors

1999 ◽  
Vol 26 (6) ◽  
pp. 869-875 ◽  
Author(s):  
J Druez ◽  
P McComber ◽  
M Farzaneh
Keyword(s):  
Field Data ◽  
Test Site ◽  
Ice Accretion ◽  
Electrical Conductor ◽  
Alarm Signal ◽  
Alarm Signals ◽  
Detector Signal ◽  
At Resonance ◽  
Data Points ◽  
Electrical Conductors

In cold regions, atmospheric icing is an important parameter for the design and reliability of exposed structures. A test site, located on Mt. Valin (Québec) Canada, is used to obtain field data on icing events. This test site mainly includes two test lines supporting four types of electrical conductors, instrumentation, and an ice detector. The ice detector monitors ice accretion by measuring the shift in frequency, at resonance, of a vibrating cylindrical probe, under the effect of the mass of ice accreted. This instrument, which is electrically de-iced, sends a cumulative alarm signal for each ice mass accretion reaching a preset value. The correlation between the ice detector signal and the mass of ice accreted on two different sized conductors is presented for three typical icing events monitored during the 1994-1995 season. In order to improve the correlation, a procedure rejects the data points corresponding to the shedding of ice during an icing event. The comparison between the mass of ice accreted on different conductors and the ice detector signal is a convenient way to calibrate the instrument. Then, these results could be used for predicting the ice mass accreted on similar cables, using the number of alarm signals from the ice detector. Results indicate the need to take into consideration the cable diameter and the apparent area of the probe with respect to the direction of droplets in the calibration of such ice detector.Key words: ice accretion, ice detector, electrical conductor, correlation, calibration, icing model, ice prediction, in-cloud icing, precipitation icing.

scholarly journals Child immune response and the role of nutrition

2016 ◽  
Vol 45 (5) ◽  
pp. 187
Author(s):  
Ariyanto Harsono
Keyword(s):  
Immune Response ◽  
Immune System ◽  
Immune Function ◽  
The Body ◽  
Alarm Signal ◽  
Alarm Signals ◽  
Close Cooperation ◽  
Stress Signals ◽  
As Stress

The immune function is designed to defendthe body in a safe and efficient way againsta variety of dangerous materials includingtoxins and infectious organisms. Mechanical andbiological barriers prevent the penetration ofexogenous material into the body. Only after thesebarriers have been breached and cells have beendirectly attacked does the immune system come intoplay. By a variety of mechanisms, certain immunecells can directly phagocytose and destroy manypathogens. They require the close cooperation ofsomatic cells, which both alert the immune systemthrough alarm signals and later participate in theeffector phase. This first alarm signal can be groupedtogether as “stress signals”, known as the innateimmune response.

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