Alarm signal

In cases where the composition of the secretion is comparatively simple, a reasonably complete picture can be obtained. For example, several species of ponerine ants produce dimethyl alkyl pyrazines in their mandibular glands, and utilize these for alarm communication. Detailed study of the behavior of 

Odontomachus troglodytes demonstrates that of the four compounds produced by workers, three, 2,6-dimethyl-3-butyl pyrazine, and its 3-pentyl and 3-hexyl homologues all release the same behavior pattern in worker ants. These ants are alerted, approach the source with mandibles opened, where some of them attack. The fourth compound, 2,6-dimethyl-3-ethyl pyrazine, has no detectable communicative role between workers, even though it is not the least abundant of the four compounds in the whole secretion. There is no qualitative difference between the behavior patterns released by the three other compounds in the secretion, and the workers response to the whole secretion can be explained in terms of any one of these single components (Longhurst et al., 1978). 

Further in-built sophistication results directly from the two different behavioral thresholds for attraction and alarm. To describe this it is necessary to know something of the way in which chemical signals are transmitted through the air. At close range, and in comparatively still air, the predominant mode of transmission is by molecular diffusion (Bossert and Wilson, 1963 see Card6 and Elkinton, Chapter 3). The active spaces for attraction and alarm, the volumes within which the concentration of chemical is at or above the behavioral threshold, will both be hemispheres if the chemical is released instantaneously on a plane surface, and their radii R at any one time t will be given by 

Several conclusions can be drawn from this equation, as applied to the alarm pheromone of Atta texana. The first is that as the amount of chemical emitted increases (i.e., Q increases), so at any one time the radii of the active spaces increase, and so does the total duration of the signal, given by the equation, derived from that above 

Furthermore, the values of K for alarm and attraction differ by a factor of 10. Thus for any value of t and Q, the active space for attraction will be greater than that for alarm (Fig. 15.4), and this will result in the responding ants receiving a sequential message. They are first stimulated by low concentrations of (+)-4-methyl-3-heptanone, and are attracted toward the source as they move in this direction they will encoimter higher concentrations of the same com-poimd, and when the ants cross the second threshold, they will be alarmed. 

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Thermal Dispersion. Thermal dispersion level switches are used on appHcations where multiple shifts inhquid characteristics are present. The unit is responsive only to a change in the thermal conductivity of the Hquid and ignores shifts in specific gravity, dielectric, density, temperature, and pressure. Units are used for alarm signal however, pump control maybe obtained using two units with a latching relay. 

Limit Switches and Stem-Position Transmitters Travel-limit switches, position switches, and valve-position transmitters are devices that, when mounted on the valve, actuator, damper, louver, or other throtthng element, detect the component s relative position. The switches are used to operate alarms, signal hghts, relays, solenoid valves, or discrete inputs into the control system. The valve-position transmitter generates a 4-20-mA output that is proportional to the position of the valve. 

Do employees know the meaning of emergeney alarm signals, as deseribed in the SAHP [OSHA Referenee. 120(l)(3)(vi)]... 

Annunciator panels should be in a central location with alarm annunciators and shutdown annunciators grouped separately. The first alarm and the first shut-down normally sound a horn and are annunciated. This is called first-out indication. Subsequent shutdown or alarm signals received by the panel are either not annunciated or are annunciated in a different manner so that the operator can determine the initiating cause of the process upset. 

Alarm signals may come from the output signal used to control an operational valve. Shutdown signals should come from a completely separate instrument not dependent upon a normally used output signal for operation. 

The on-line feed water pump tripped, but the operator ignored the alarm signal, presumably because he thought the backup pump w ould start up automatically. 

Cabled housing with electronic service and alarm signal... 

Melde-. registration, recording, record, intelligence alarm, signal. 

Intruder alarms are designed to give a warning of the presence of an intruder within or attempting to enter the protected area. Alarm systems may act as a deterrent to the casual or opportunist thief but they will do little or nothing to prevent a determined intrusion, and to be effective they must provoke an early response from the appropriate authority (in most cases the police). The warning may be a local audible device, but normally the alarm signal is transmitted by the telephone network to a central station operated by a security company on a 24-hour basis. 

The alarm and telephone companies provide a comprehensive range of facilities for the transmission and receipt of alarm signals. The choice of signaling system will be determined by the security risk. 

Cocke R., Moynihan J.A., Cohen N., Grata L.J., et al. (1993). Exposure to conspecific alarm signals alters immune responses in BALB-c mice. Brain Behav Immunol 7,... 

Aphidius uzbekistanicus Aphidius sp. Host alarm signal [attraction] (E)-p-Farnesene 48 [88]... 

Alarm signals produced by stressed hosts also attract parasitoids. For example, stressed aphids (Aphidius sp.) were attractive to female parasitoids of two... 

Gas sensors are of importance for a variety of environmental, industrial, medical, scientific and even domestic applications. The gas may be, for example, hazardous to human health, an atmospheric pollutant, or important, in terms of its concentration, for an industrial or medical process. Apart from systems merely providing an alarm signal, it is frequently required to obtain accurate real-time measurements of the concentration of a particular target gas, often in a mixture of other gases. 

Regime precautions compose an aggregate of the rules for securing the safety of objects or installations. Electrical security system, access and departure into facility of employees and vehicles, fire alarm signalization etc. 

All alarm signals showed the correct identification and the acoustic alarm warned about the event. 

Alarms should be initialed by the local or main control facility for the location. Manual activation means should be provided for all emergency, fire, and toxic vapor alarm signals. Activation of fire suppression systems by automatic means should also indicate a facility alarm. Most fire and gas detection systems are also set to automatically activate alarms after confirmation and set points have been reached. Manual activation of field or plant alarm stations should activate the process or facility alarms. 

Whenever ambient noise levels are above emergency alarm signals or tones, flashing lights or beacons should be considered that are visible in all portions of the affected area. The color of flashing lights should be consistent with the safety warning colors adopted at the facility. 

Hypothesis 4 An alarm signal exists which reduces time to metamorphosis and mass at metamorphosis of cane toad tadpoles. 

Brizzi, R., Delfino, G. and Pellegrini, R. (2002) Specialized mucous glands and their possible adaptive role in the males of some species of Rana (Amphibia, Anura). J. Morph. 254, 328-341. Chen, C. and Osuch, M. V. (1969) Biosynthesis of bufadienolides - 3Bhydroxycholonates as precursors in Bufo marinus bufadienolides synthesis. Biochem. Pharmacol. 18, 1797-1802. Chivers, D. P. and Smith, R. J. F. (1998) Chemical alarm signalling in aquatic predator-prey systems a review and prospectus. Ecosci. 5, 338-352. 

A control panel receives information from the sensors and sends it to an appropriate location, such as to a central operations station or to a twenty-four-hour monitoring facility. Once the alarm signal is received at the central monitoring location, personnel monitoring for alarms can respond (such as by sending security teams to investigate or by dispatching the fire department). 

An annunciator responds to the detection of an event by emitting a signal. This signal may be visual, audible, electronic, or a combination of these three. For example, fire alarm signals will always be connected to audible annunciators, whereas intrusion alarms may not be. 

Alarms can be reported locally, remotely, or both locally and remotely. A local alarm emits a signal at the location of the event (typically using a bell or siren). A local only alarm emits a signal at the location of the event but does not transmit the alarm signal to any other location (i.e., it does not transmit the alarm to a central monitoring location). Typically, the purpose of a local only alarm is to frighten away intruders, and... 

Once a sensor in an alarm system detects an event, it must communicate an alarm signal. The two basic types of alarm communication systems are hardwired and wireless. Hardwired systems rely on wire that is run from the control panel to each of the detection devices and annunciators. Wireless systems transmit signals from a transmitter to a receiver through the air—primarily using radio or other waves. Hardwired... 

An exterior intrusion sensor is a detection device that is used in an outdoor environment to detect intrusions into a protected area. These devices are designed to detect an intruder and then communicate an alarm signal to an alarm system. The alarm system can respond to the intrusion in many different ways, such as by triggering an audible or visual alarm signal, or by sending an electronic signal to a central monitoring location that notifies security personnel of the intrusion. 

Borg-Karlsson et al. [110] showed that the pygidial gland secretions of certain Gyrinus species may contain volatiles which act as intra- and interspecific alarm signals. 

In some instances also, for example in the processing of isocyanates, which are highly toxic in minute quantities and generally processed inside an enclosure, it is desirable to consider the use of alarm signals to indicate the occurrence of a leakage or to demand the evacuation of an area. 

Not all releaser pheromones are sex attractants. One alternative example of a releaser pheromone is the sending out of an alarm message, warning other members of the species that some threat is at hand. The California sea anemone Anthopleura elegantissima provides a neat example of alarm signaling. 

Each type of emergency alarm or signal must clearly inform those onsite of the actions to be taken. This requires training and testing of the alarm so personnel can recognize the alarm and take appropriate action. Some of these alarms may be automatic. For example, detection of a fire may be signaled directly by the protection or detection system rather than by an individual. This alarm signal may alert not only personnel in the immediate area, but all facility personnel and the community fire department. 

Carbon dioxide gas is an asphyxiant, a potent respiratory stimulant, and both a stimulant and depressant of the central nervous system. Fatalities have occurred after people have entered enclosures where air has been largely displaced by CO2. Therefore, fixed, automatic CO2 systems require a time delay pre-evacuation alarm period (often 30 seconds), warning signs, and an alarm signal incorporated into the system design to allow sufficient time for personnel evacuation prior to CO2 release. Verification of the oxygen level must be made prior to reentry. 

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