Reinforcement, intermittent

Pipe reinforcement pads can be vented by intermittent rather than continuous welding, or a -in. or l4-in. hole can be drilled in the pad. 

Nitrile rubbers, including fiber-reinforced varieties, are used both as radial shaft-seal materials and as molded packing for reciprocating shafts. They have excellent resistance to a considerable range of chemicals, with the exception of strong acids and alkalis, and are at the same time compatible with petroleum-based lubricants. Their working temperature range is from —1°C to 107°C (30°F to 225°F) continuously and up to 150°C (302°F) intermittently. When used on hard shafts with a surface finish of, at most, 0.00038 mm root mean square (RMS), they have an excellent resistance to abrasion. 

There is some evidence of a synergistic effect on reinforcement with concurrent administration of benzodiazepines and opioids (Walker and Ettenberg 2003). Cocaine abusers are less likely than opioid abusers to abuse benzodiazepines, preferring alcohol and opioids as secondary drugs of abuse. The most common pattern of benzodiazepine misuse in these individuals is intermittent use of therapeutic or supratherapeutic doses to counter unwanted effects of cocaine. 

However, reinforcement does not necessarily happen all the time or even regularly. For example, even though many of us work every day, we do not necessarily get paid at the end of that day for what we did. And in some instances reinforcement is unpredictable, like when you receive an unexpected phone call that is rewarding to you from a close friend. When reinforcement doesn t occur in a predictable way, it is referred to as being on a variable or intermittent (random or unpredictable) schedule (or pattern). Behavioral researchers have found that a variable reinforcement schedule produces behavior patterns that are much more difficult to change than behavior patterns reinforced regularly. 

Variable or intermittent reinforcement happens after tolerance develops, and occurs in a random and unpredictable fashion that keeps the person returning to the drug for the next good high. 

PJ s experiences with drugs were not always good sometimes she had a bad trip , sometimes she did not get stoned at all if the drugs were contaminated with too many adulterants. The expected consequence does not need to occur every time in order for the behaviour to be strengthened. Gambling is the obvious example. Reinforcement that occurs only intermittently may be even more powerful man that which occurs every time. 

Clear polyester sheet stock and rods are available13 and, like reinforced polyester plastic, may be drilled, sawed, and machined. This clear plasic is harder than poly(methyl methacrylate) and much more solvent resistant than either po-lyfmethyl methacrylate) or polystyrene. As with all thermosetting plastics, it may not be heat-formed or solvent-bonded. However, bonding with epoxy cements is satisfactory. This plastic is claimed to give continuous service at 80°C and intermittent service up to 150°C. 

Ettenberg A, Camp CH (1986b) A partial reinforcement extinction effect in water-reinforced rats intermittently treated with haloperidol. Pharmacol Biochem Behav 25.1231-1235. 

Gray T, Wise RA (1980) Effects of pimozide on lever pressing behavior maintained on an intermittent reinforcement schedule. Pharmacol Biochem Behav 72 931-935. 

Tombaugh TN, Anisman H, Tombaugh J (1980) Extinction and dopamine receptor blockade after intermittent reinforcement training failure to observe functional equivalence. Psychopharmacology 70 19-28. 

Reinforced nylon containing molybdenum disulphide is very commonly used for gears in low-stress situations such as windscreen wipers and car door window winders. It gives good wear and impact resistance and quiet operation, and is particularly useful where oil or grease lubrication is marginal or intermittent. 

In the real world, consequence stimuli do not necessarily follow every occurrence of the response. In fact, typically, consequences follow the response on an intermittent basis. Paychecks, for example, are typically distributed on a weekly, biweekly, or even monthly basis, not after each instance of work-related activity that occurs. The pianist plays the entire piece of music before the audience applauds. This strategy of intermittent reinforcement of responding actually provides greater behavioral efficiency and economy as well as greater response strength and persistence than does continuous reinforcement. A response that has been reinforced after every occurrence declines much more rapidly when reinforcement is withheld (extinction) than does one that has been reinforced on an intermittent schedule. 

Performance generated by intermittent schedules of reinforcement has played an important role in behavioral pharmacology and is proving a useful tool in behavioral toxicology. On an intermittent schedule, an animal is not reinforced for every response but for a number of responses according to certain rules . Most intermittent schedules are based on reinforcing the organism as a function of the number of responses emitted, some temporal requirement for emission of responses, or a combination of these. For example, a fixed ratio (FR)... 

Intermittent schedules may also be maintained by negative reinforcement, usually by a brief mild electric shock. The most popular of these is continuous or Sidman avoidance in which each response postpones a shock by a fixed amount of time. By spacing its successive responses within this time interval, the animal may postpone shock indefinitely. This schedule is particularly useful as a comparison to behavior generated by positive reinforcement if a toxicant is suspected of producing anorexia. Simple intermittent schedules such as these have been used fairly widely in behavioral toxicology and have proved to be sensitive to the effects of a number of industrial and environmental toxicants. 

Intermittent schedules of reinforcement can be combined to form more complicated schedules such as multiple schedules of reinforcement. For example, if FR and FI schedules are presented to an animal in succession during a single test session, the resulting multiple schedule is termed a multiple FR-FI schedule. Each component of the multiple schedule is independent and occurs in the presence of a different external discrimination stimulus that signals the schedule component in effect. Schedule components are typically presented in an alternating fashion, first one schedule and then the other this allows the investigator to collect data on both types of behavior almost simultaneously. This schedule in particular has proved to be useful in detecting behavioral toxicity. 

The olfactory perception can be reinforced by sniffing i.e. by swirling the air intermittently over the ethmoid bone below the olfactory epithelium. The swirling effect causes the active components producing the smell to flow past the olfactory epithelium several times (instead of just once), thereby reinforcing the effect (particularly important in quality testing in the case of weak samples or samples with only very minor differences between them). 

N. R. Buenfeld, Cathodic protection afforded by an intermittent current applied to reinforced concrete . 

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