bluuebunny/crossref_metadata_2025 huggingface dataset:
ERRORLESS TRANSFER OF A DISCRIMINATION ACROSS TWO CONTINUA1
Authors: Terrace H. S.
Published: March 2006

A procedure developed earlier (Terrace, 1963) successfully trained a red‐green discrimination without the occurrence of any errors in 12 out of 12 cases. Errorless transfer from the red‐green discrimination to a discrimination between a vertical and a horizontal line was accomplished by first superimposing the vertical and the horizontal lines on the red and green backgrounds, respectively, and then fading out the red and the green backgrounds. Superimposition of the two sets of stimuli without fading, or an abrupt transfer from the first to the second set of stimuli, resulted in the occurrence of errors during transfer. Superimposition, however, did result in some “incidental learning”. Performance following acquisition of the vertical‐horizontal discrimination with errors differed from performance following acquisition without errors. If the vertical‐horizontal discrimination was learned with errors, the latency of the response to S+ was permanently shortened and errors occurred during subsequent testing on the red‐green discrimination even though the red‐green discrimination was originally acquired without errors. If the vertical‐horizontal discrimination was learned without errors, the latency of the response to S+ was unaffected and no errors occurred during subsequent testing on the red‐green discrimination.
A SEQUENTIAL RESPONSE METHOD OF STUDYING COMPLEX BEHAVIOR IN ANIMALS AND ITS APPLICATION TO THE MEASUREMENT OF DRUG EFFECTS1
Authors: Polidora V. J.
Published: March 2006

A behavioral testing method was demonstrated to be applicable to the study of detrimental drug effects on complex behavior in rats. The method required the subject (S) to respond in a certain sequence to four identical response sites spaced 90° apart within a cylindrical test compartment. After each S was shaped to perform its one particular sequence within this quadrilaterally symmetrical environment, and its performance was brought to a stable level, drug effects were then studied on a battery of such Ss whose sequential response habits were representative of a continuum of sequence complexity. Experiments with a drug which induces hallucinatory and confusional states in man showed that the method yields in the rat quantitative measures of detrimental behavioral effects in terms of dose‐response and dose‐time relationships in addition to providing an estimate of the interactive effect between drug dose and behavioral complexity. It was found that for a given magnitude of behavioral detriment, drug dose and behavioral complexity of sequence were inversely related. That is, a S required to perform a simple sequence needed a larger drug dose to interfere with its habit a unit amount than did a S with a more complex one; or, expressed another way, a given drug dose had a greater behavioral effect the more complex the sequence. Finally, an empirical ranking of response sequences along a functional behavioral complexity dimension was presented.
CONCURRENT PERFORMANCES: A BASELINE FOR THE STUDY OF REINFORCEMENT MAGNITUDE1
Authors: Catania A. Charles
Published: March 2006

When a pigeon's pecking on a single key was reinforced by a variable‐interval (VI) schedule of reinforcement, the rate of pecking was insensitive to changes in the duration of reinforcement from 3 to 6 sec. When, however, the pigeon's pecking on each of two keys was concurrently reinforced by two independent VI schedules, one for each key, the rate of pecking was directly proportional to the duration of reinforcement.
AMPLITUDE‐INDUCTION GRADIENT OF A SMALL‐SCALE (COVERT) OPERANT1
Authors: Hefferline Ralph F. , Keenan Brian
Published: March 2006

An invisibly small thumb‐contraction was conditioned under secondary positive reinforcement (money) in four adult human subjects without their observation of the response. Electromyographic detection enabled the experimenter to reinforce the response by advancing on the subject's illuminated scoreboard the count of nickels earned. A light‐beam galvanometer recorded on photosensitive paper not only those instances of the response which were of the size pre‐selected for reinforcement but also those too small or too large to qualify. From the developed record cumulative response curves were constructed for each of the variously sized subclasses of the operant. Histograms, too, were plotted showing response‐frequency by subclass for each 10‐min interval of the experimental session. Before conditioning, response frequency was radically skewed toward the large‐amplitude end of the distribution. The effect of conditioning was to normalize the distribution, with the middle‐sized subclass (the one reinforced) becoming modal. This entailed reduced frequency of responses in subclasses smaller than the one reinforced. In extinction the original skew was strikingly restored in three of the four cases.
BEHAVIORAL EFFECTS OF CAFFEINE, METHAMPHETAMINE, AND METHYLPHENIDATE IN THE RAT
Authors: Mechner Francis , Latranyi Miklos
Published: March 2006

It was possible to distinguish three closely‐related psychomotor stimulants, caffeine, methamphetamine, and methylphenidate, by means of two operant behavior procedures, fixed interval and fixed number. Under the fixed interval procedure, the percentage change in the number of RBs per reinforcement was significantly smaller with caffeine than with methamphetamine or methylphenidate (p < .001). Under the fixed number procedure, the percentage change was significantly smaller with methamphetamine than with caffeine or methylphenidate (p < .001). Thus, methylphenidate had a methamphetamine‐like effect under fixed interval and a caffeine‐like effect under fixed number.
RESPONSE COST AND THE AVERSIVE CONTROL OF HUMAN OPERANT BEHAVIOR1
Authors: Weiner Harold
Published: March 2006

The effects of cost (point‐loss per response) upon human avoidance, escape, and avoidance‐escape behavior maintained by PLPs (point‐loss periods) were investigated. Cost had a marked but differentially suppressive effect upon responding under all schedules. The greatest number of PLPs taken under cost occurred on the escape schedule. In most instances PLPs were more frequent on the avoidance‐escape schedule than on the avoidance schedule under cost. Inferior avoidance performance appeared only under cost conditions. Under no‐cost, all subjects (Ss) successfully avoided all PLPs after the first hour of conditioning. These results indicate that the development and maintenance of human avoidance and escape behavior may, in part, be dependent upon response cost conditions. Aversive control of human operant behavior may be limited without an adequate specification of response‐cost conditions.
SOME PARAMETERS AFFECTING THE DISTRIBUTIONAL PROPERTIES OF OPERANT‐LEVEL RUNNING IN RATS1
Authors: Premack David , Schaeffer Robert W.
Published: March 2006

Six adult female albino rats were subjected to operations known to increase the frequency of wheel‐running. Operations included limited access to wheel, food deprivation, and protracted maintenance on a 24‐hr feeding schedule. A distributional analysis of response duration, burst duration, and inter‐burst interval showed that the increased frequency in all cases arose mainly from a shortening of the interval between successive bursts. Only short‐term food deprivation produced any notable increase in burst length, and even here changes in both speed of the individual responses and in number of responses per burst were slight compared to changes in inter‐burst interval.
PARTIAL NEGATIVE REINFORCEMENT: FIXED‐RATIO ESCAPE
Authors: Hendry Derek P. , Hendry Louise Simpson
Published: March 2006

Rats were unable to sustain performance when eight bar‐presses turned off shock (—FR 8). In a second experiment, thirsty rats were able to maintain a moderate response rate when performance on —FR 8 was also reinforced with water. Some rats continued to bar‐press on —FR 8 after withdrawal of positive reinforcement, but at a much lower rate. A possible explanation of the results is that during intermittent escape conditioning in a free‐responding situation the absence of shock itself acquires aversive properties.
TOWARDS AN EMPIRICAL CALCULUS OF REINFORCEMENT VALUE
Authors: Verhave Thom
Published: March 2006

Only one of two keys reinforces the subject with food. This key can assume one of two colors, each associated with a different fixed‐ratio schedule for obtaining reinforcement. The function of the second key is to permit the animal to switch from the long schedule to the short schedule. If the difference between the ratio schedules is large enough, a preference for the shorter schedule is demonstrable. A quantitative index of preference is obtained as follows: each time the animal switches to the shorter schedule, the number of pecks required to produce the next switch is increased. As the “ante” on the switching key increases, the effective difference between the two ratio schedules decreases. After each food reinforcement, when the bird is exposed to the choice‐situation, it takes longer before the bird switches again. This is used to “titrate” the bird's preference. If it does not switch within x sec, the progressively increasing ratio schedule of the switching key is decreased. A specific value, in terms of a rather specific number of responses the bird settles at on the choice key, is obtained. This equilibrium is employed as a dependent variable. Several variables of which it is a function are explored.
DEVELOPMENT OF A COMPLEX MULTIPLE SCHEDULE IN THE CHIMPANZEE
Authors: Belleville Richard E. , Rohles Frederick H. , Grunzke Marvin E. , Clark Fogle C.
Published: March 2006

The development of chimpanzee behavior on a four‐component, three‐lever multiple schedule is described. Component schedules included the Sidman avoidance procedure with a concurrent discriminated avoidance schedule on a second lever, fixed ratio performance for food, differential reinforcement of low rate for water requiring a dual response chain, and a symbol discrimination task for continuous food reinforcement using three levers. The avoidance component of this schedule was employed during the January 31, 1961 suborbital space flight of the chimpanzee “Ham.” On November 29, 1961, the chimpanzee “Enos” performed on the multiple schedule during three orbits around the earth in a Mercury capsule.
RATE‐CHANGE EFFECTS WITH EQUAL POTENTIAL REINFORCEMENTS DURING THE “WARNING” STIMULUS1
Authors: Pliskoff Stanley S.
Published: March 2006

Two pre‐schedule‐change stimuli were superimposed on the same VI baseline and were thereby equated with respect to reinforcement potential. One such stimulus preceded a transition to an extinction schedule or a VI schedule of lower reinforcement frequency while the other preceded a transition to a VI schedule of higher reinforcement frequency. It was found that response rate during the warning stimulus was greater preceding the transition to the lower reinforcement frequency than it was preceding the transition to the higher reinforcement frequency. That difference was often evidenced by an absolute increase and decrease in rate, in conformity with previous findings on the topic. The present experiment extends previous findings in several ways, including the presentation of quantitative estimates of the effects.
STIMULUS ASPECTS OF AVERSIVE CONTROLS: THE RETENTION OF CONDITIONED SUPPRESSION1
Authors: Hoffman Howard S. , Fleshler Morton , Jensen Philip
Published: March 2006

Three years ago a tone ending in unavoidable electrical shock was periodically presented to pigeons while they pecked a key for food. When pecking was disrupted by tone, shock was disconnected and the training tone as well as tones of different frequencies were presented. At first, all tones caused a reduction in the rate of pecking, but as testing proceeded, suppression began to extinguish and the gradient narrowed. In the present work, testing was resumed after a 2½‐yr interruption. Analysis of the gradients obtained just before and just after the interruption yielded no evidence of changes with the passage of time. As testing proceeded, however, extinction of suppression continued and the gradient all but disappeared. In subsequent experiments with these subjects (Ss) it was found that the presentation of free shocks caused a reappearance of the gradient and that this effect persisted in reduced amount for several sessions after the shock condition was terminated.
PUNCHED CARD PROGRAMMING AND RECORDING TECHNIQUES EMPLOYED IN THE AUTOMATION OF THE WGTA1
Authors: Polidora V. J. , Main Willett T.
Published: March 2006

A system of punched card programming and recording of primate discrimination learning experiments is described to illustrate the application of these techniques to the automation of the discrete trial learning situation, allowing for punched card recording and subsequent digital computer data analyses without intermediate data reduction. The system was also designed to control several potential sources of variability inherent in the conventional WGTA testing mode, including 1) the subject's (S's) motivation to test on each trial, 2) S's attention to the stimuli, and 3) the rate of trial presentation so as to be more under S's control. Reliable techniques of punched card programming and recording are detailed.
EFFECTS OF VARYING CYCLE LENGTH IN A TAU REINFORCEMENT SCHEDULE1
Authors: Cumming W. W. , Schoenfeld W. N.
Published: March 2006

A temporally defined reinforcement schedule within the tau system of classification was studied, with pigeons as subjects and with cycle length as the independent variable. As cycle length decreased, response rates increased, responses‐per‐reinforcement went through a maximum, while the number of reinforcements‐per‐session increased. The first two functions are attributed to changes in the discriminability of the τD and τΔ components of the cycle, while the latter seems to result from changes in the relative durations of reinforcement time and τΔ time.
A SYSTEM FOR PROGRAMMING EXPERIMENTS AND FOR RECORDING AND ANALYZING DATA AUTOMATICALLY1
Authors: Herrick Robert M. , Denelsbeck John S.
Published: March 2006

A system designed for use in complex operant conditioning experiments is described. Some of its key features are: (a) plugboards that permit the experimenter to change either from one program to another or from one analysis to another in less than a minute, (b) timesharing of permanently‐wired, electronic logic components, (c) recordings suitable for automatic analyses. Included are flow diagrams of the system and sample logic diagrams for programming experiments and for analyzing data.
BAR HOLDING DURING ESCAPE CONDITIONING
Authors: Migler Bernard
Published: March 2006

To analyze bar‐holding behavior during escape conditioning three rats were trained to escape from shock by pressing a bar, and three were trained to escape by releasing a bar. Bar holding behavior was stronger and more stable under the release condition. These effects were related to the relative shock duration of onbar versus offbar shocks.
RATE DIFFERENTIAL REINFORCEMENT IN MONKEY MANIPULATION
Authors: Premack David
Published: March 2006

A set of four manipulanda were presented to four Cebus monkeys, individually, and later in pairs. Step 1 provided an estimate of each S's probability of operating each item, while Step 2 determined whether pairing the items would disturb the ordinal relations among individual response probabilities. Both procedures provided information necessary for testing the assumption that a reinforcer is simply a contingent response whose independent probability of occurrence is greater than that of the associated instrumental response. Step 3 tested this assumption by again presenting pairs of items, but with one locked and its operation made contingent upon operation of the free item of the pair. The four Ss differed markedly in the extent to which the items produced different independent response probabilities, and correspondingly, in the extent to which the contingent pairs subsequently produced reinforcement. Confirmation of the present assumptions came primarily from one S, which differed substantially on the individual items, and showed five cases of reinforcement, all in the predicted direction. Further, reinforcement was shown by an increase in both contingency and extinction sessions. Finally, the response of intermediate probability reinforced the response of least, but not the one of greatest, probability, indicating that a reinforcer cannot be identified absolutely, but only relative to the base response.
FREQUENCY OF REINFORCEMENT AS A PARAMETER OF CONDITIONED SUPPRESSION
Authors: Lyon David O.
Published: March 2006

Two pigeons were trained on a multiple VI‐1; VI‐4 min schedule for food reinforcement until a stable differential rate of response was established. Each component of the multiple schedule was in effect for 10 min and was separated from the other by 1 min time out. An Estes‐Skinner conditioned suppression procedure was superimposed on each component of the schedule. The relative magnitude of the suppression behavior was measured during its acquisition and extinction, and at CS durations of 100, 200, and 300 sec. The initial magnitude of the suppression behavior was less severe on the VI‐1 baseline than on the VI‐4, and it extinguished more rapidly on the VI‐1. As the relative duration of the CS was increased, the suppression behavior became less severe on both baselines, but the initial differential magnitude in the suppression remained intact.
DIFFERENTIAL REINFORCEMENT OF VOCAL DURATION1
Authors: Lane Harlan
Published: March 2006

The effects of differential reinforcement of vocal duration were examined in a series of experiments in which each of 28 subjects (Ss) emitted a vowel whenever a light was flashed. In the first phase of each experiment, a penny was dispensed after each of 20 responses. In the second and subsequent phases, only those responses whose durations exceeded a criterion were reinforced; when 10 successive reinforcements were presented, one phase was terminated and the next begun. The criterion for reinforcement in each phase was determined by a different schedule in each of six experiments; it ranged from 80 to 120 per cent of the mean duration of the 10 terminal responses in the prior phase. Differential reinforcement effected a large and systematic change in the duration of vocal responses as long as the responses selected for reinforcement had a sufficiently high probability of occurrence. This requirement was formulated as the difference between the criterion duration and the mean duration of the terminal responses in the prior phase, divided by their standard deviation. This statistic, named the shaping index, was correlated with the number of responses emitted before each phase was terminated. It was found to be large whenever the shaping process failed. Many Ss failed to tact the reinforcement contingency despite marked changes in their vocal behavior and extensive probing by a questionnaire, administered at the end of each session.
INTER‐REINFORCEMENT TIMES FOR THE BAR‐PRESSING RESPONSE OF WHITE RATS ON TWO DRL SCHEDULES1,2
Authors: Farmer John , Schoenfeld W. N.
Published: March 2006

A knowledge of inter‐reinforcement times (ISRT) seems of interest because, among other reasons, they bear on the variable of “reinforcement density” in behavior theory. ISRT data were here recorded for bar‐pressing responses by two white rats working on DRL 10 sec and DRL 40 sec. Sample inter‐response time (IRT) distributions and cumulative records were taken simultaneously for comparison purposes. ISRT sequences and distributions have certain characteristics that urge further investigation.
SOME NOTES ON TIME OUT FROM REINFORCEMENT1
Authors: Zimmerman J. , Ferster C. B.
Published: March 2006

Pigeons produced food on a fixed‐ratio schedule by pecking at one key, and an SΔ period by pecking at a second (switching) key. Switching behavior was examined as a function of (a) size of the fixed ratio, (b) whether the SΔ was of fixed duration or could be determined by the bird, (c) the introduction of a novel food SD, (d) extinction of food responding, and (e) the stimuli associated with the SD and SΔ conditions. No monotonic relationship was obtained between ratio size and switching behavior. Switching behavior was, however, influenced by many variables. The results suggest that an interpretation of switching behavior in terms of its being reinforced by the removal of aversive conditions, is open to considerable question.
A LIQUID‐DELIVERY UNIT FOR OPERANT SCHEDULES
Authors: Green Phillip C.
Published: March 2006

I wish to express my thanks to Mr. Harold Flanary, Electronics Engineer at the NIMH Addiction Research Center, for his invaluable assistance in the design and construction of this apparatus.
APERIODICITY AS A FACTOR IN CHOICE1
Authors: Herrnstein R. J.
Published: March 2006

Four pigeons were trained to peck at either of two response‐keys. Pecks at either key occasionally produced a secondary reinforcer, in the presence of which further pecks occasionally produced food, the primary reinforcer. All pigeons showed a consistent preference for variable (as compared to fixed) interval schedules of primary reinforcement.
CONTINUOUS OPPORTUNITY FOR REINFORCING BRAIN STIMULATION1
Authors: Valenstein Elliot S. , Beer Bernard
Published: March 2006

The performance of a rat provided with continuous opportunity to obtain reinforcing brain stimulation over a 20‐day period is described in detail. The animal averaged 29.2 responses per min during the entire time. Testing session was terminated by experimenters, but a day‐by‐day analysis of behavior provided no evidence that the animal would have stopped responding.
SHAPING OF THREE‐MAN TEAMS ON A MULTIPLE DRL‐DRH SCHEDULE USING COLLECTIVE REINFORCEMENT1
Authors: Burnstein David D. , Wolff Peter C.
Published: March 2006

Five three‐man teams were conditioned to a multiple DRL‐DRH schedule during five daily sessions of 3 hr each. The teams were conditioned on the basis of their cumulative response rate regardless of the contributions of individual members. Two individually conditioned Ss were run under a similar schedule for comparison. Although all teams demonstrated some differentiation of response rate under the two legs of the schedule, this difference was not achieved as rapidly, nor was it as stable, as the differentiation in rates achieved in individually conditioned Ss. Team members displayed a variety of response rates as a result of collective team conditioning. Often, individual response rates interfered with obtainment of team reinforcement. The individual team members displayed little SD control in comparison with the individually conditioned Ss. In general the results suggest that collective reinforcement is highly inefficient in comparison with procedures employing individual feedback.
THE SUCCESSIVE DIFFERENTIATION OF A LEVER DISPLACEMENT RESPONSE1
Authors: Herrick Robert M.
Published: March 2006

Maximum displacements of lever presses by rats were recorded under eight successively‐smaller reinforcement zones (RZ). The largest RZ included displacements from 3° to 44°; the smallest, from 24° to 29°. As the RZ decreased, displacement distributions reflected a least‐effort tendency: distributions peaked at the lower limit of RZ and most non‐reinforced presses fell just below the lower limit. Successive distributions (a) differed significantly in shape, (b) showed reduced variability, and (c) indicated more presses and more presses per reinforcement. Prolonged training under the smallest RZ gave no improvement in performance.
MULTIPLE BASELINE INVESTIGATION OF STIMULUS FUNCTIONS IN AN FR CHAINED SCHEDULE1,2
Authors: Thomas John R.
Published: March 2006

The performance of pigeons was studied on a multiple schedule in which a three‐member FR chained schedule alternated with a three‐member FR tandem schedule. The chain and tandem schedules contained identical response requirements. In the chained schedule, more pausing and lower response rates occurred in the first and second components than occurred in the tandem control, in which the same exteroceptive stimulus was associated with all components. Because the reinforcement and response contingencies were identical in the chain and tandem schedules, differences in performances can be attributed to stimulus control.
TIMING BEHAVIOR AND CONDITIONED FEAR
Authors: Migler Bernard , Brady Joseph V.
Published: March 2006

Rats were trained on a two‐response timing procedure which required that response B follow response A by at least a minimum specified interval in order to be reinforced with food. Repeated presentation (5 min on, 5 min off) of an auditory warning stimulus terminated by a brief electric shock to the feet (conditioned fear) produced a marked suppression in the frequency of A‐to‐B response sequences during the warning stimulus. The distribution of A‐to‐B interresponse times (timing behavior), however, did not change during the warning stimulus.
SELECTIVE PUNISHMENT OF FIXED‐RATIO PERFORMANCE1
Authors: Dardano J. F. , Sauerbrunn D.
Published: March 2006

Key‐pecking of pigeons, maintained by an FR 50 grain reinforcement schedule, was punished by shocking the first, middle, or last response of the ratio. Under high shock levels, the three punishment conditions produced differential effects on the behavior. Punishment of the first response of the ratio resulted in consistent and extended post‐reinforcement pausing and frequent extended breaks after the initial response(s) of the ratio. Punishment of the 25th response disrupted responding in the first half of the ratio with little effect on the last half of the ratio. Punishment of the final response resulted in breaks and local rate changes in various parts of the ratio. Durations of pauses after reinforcement were more variable when the 25th and 50th responses were punished relative to those when the first response was punished.
OPERANT CONDITIONING OF GOATS1
Authors: Wenzel Bernice M. , Baldwin Basil A. , Tschirgi Robert D.
Published: March 2006

A procedure is described for establishing an operant response in goats. The operanda are two lucite panels which can be transilluminated. The goats press the panels with their muzzles and are reinforced with whole oats. All six subjects showed reliable and accurate performance in brightness discrimination, including cessation of responding during time‐out periods.
ERRORLESS ESTABLISHMENT OF VISUAL DISCRIMINATION USING FADING PROCEDURES1
Authors: Moore Robert , Goldiamond Israel
Published: March 2006

A visual discrimination task involved presenting a triangle briefly as a sample. When it was withdrawn, this triangle and two others differing slightly in degree of rotation were presented in different positions, with S required to locate the sample that had been presented. Discrimination proved difficult for preschool children. When only the correct triangle was illuminated, discrimination was readily established. The brightness difference between correct and incorrect matches was gradually faded out by increasing the intensity of the incorrect matches, until they were equal in brightness to the correct match. The discrimination established by brightness difference was maintained in its absence, thereby transferring stimulus control from brightness to form, in an almost errorless sequence.
SECONDARY REINFORCEMENT AND RATE OF PRIMARY REINFORCEMENT1
Authors: Herrnstein R. J.
Published: March 2006

Four pigeons were trained to peck at either of two response‐keys. Pecking at either key occasionally produced a secondary reinforcer. Then, in the presence of the secondary reinforcer, further pecking occasionally produced the primary reinforcer, food. The relative rate at which each pigeon pecked to obtain a secondary reinforcer equalled the relative rate of primary reinforcement in its presence.
MODIFICATION OF ESCAPE RESPONDING IN HUMANS BY INCREASING THE MAGNITUDE OF AN AVERSIVE EVENT1
Authors: Weiner Harold
Published: March 2006

Escape responding of humans on an avoidance‐escape schedule was replaced by avoidance responding by increasing the magnitude of the aversive stimulus. The aversive stimulus consisted of a point loss period. The shift from escape to avoidance responding was effected under a condition of response cost.
RESPONSE COST EFFECTS DURING EXTINCTION FOLLOWING FIXED‐INTERVAL REINFORCEMENT IN HUMANS
Authors: Weiner Harold
Published: March 2006

This study examined the effects of response‐produced cost upon human observer responses during extinction following FI reinforcement. Relative to a no‐cost condition, cost produced marked and rapid response attenuation.
CONDITIONING HISTORY AND HUMAN FIXED‐INTERVAL PERFORMANCE1
Authors: Weiner Harold
Published: March 2006

The effects of two different conditioning histories upon human operant behavior under a FI 10‐sec schedule of point reinforcements were investigated. Relatively high rates of continuous inter‐reinforcement responding characterized the FI 10‐sec performance of subjects with an FR 40 conditioning history. Low response rates with little or no inter‐reinforcement responding were emitted by Ss with a DRL 20‐sec conditioning history.
EFFECT OF PRIOR PAVLOVIAN DISCRIMINATION TRAINING UPON LEARNING AN OPERANT DISCRIMINATION1
Authors: Bower Gordon , Grusec Theodore
Published: March 2006

The effect of Pavlovian discrimination training with two stimuli upon subsequent learning of an operant discrimination involving those stimuli was studied. After preliminary lever press training, the lever was removed and thirsty rats received noncontingent pairings between S1 (a tone or a clicker) and water reinforcements, whereas S2 (a clicker or a tone) occurred always without reinforcement. This procedure presumably established S1 as a positive CS for respondent behavior, whereas S2 was established as an inhibitory CS. Following this training, the lever was reintroduced and the rats were trained on an operant (lever pressing) discrimination involving S1 and S2. For the Consistent Ss, S1 was the SD and S2 the SΔ in the operant discrimination; for the Reversed Ss, S2 served as SD and S1 as SΔ. The Consistent Ss learned the operant discrimination significantly faster than did the Reversed Ss. The result emphasizes the importance of respondents, conditioned to SD and SΔ, which modulate operant performance to these stimuli.
TEMPORALLY SPACED RESPONDING BY PIGEONS: DEVELOPMENT AND EFFECTS OF DEPRIVATION AND EXTINCTION1
Authors: Reynolds G. S.
Published: March 2006

In the first five or six sessions on a DRL 20‐sec schedule of reinforcement there developed a stable performance characterized by a relatively constant conditional probability of occurrence (IRTs/op) of interresponse times (IRTs) of durations greater than 5 or 6 sec. Extinction and the level of deprivation changed both the overall rate of responding and the form of the function relating the duration of an IRT to its value of IRTs/op. The value of IRTs/op decreased more rapidly for short than for longer IRTs, resulting in the emergence of a finer discrimination of IRT duration.
RESPONSE COST AND FIXED‐RATIO PERFORMANCE
Authors: Weiner Harold
Published: March 2006

The effects of several conditions of response cost (response‐produced point loss) upon FR 50 performance maintained by 100‐point reinforcements were investigated. Post‐reinforcement pauses did not appear under no‐cost (no points deducted per response) conditions. Such pauses were effected, however, by introducing 5‐sec periods of one‐point and two‐point costs after each reinforcement. Continuous response cost did not affect responding as long as the cost was less than the 100‐point reinforcements. Rapid cessation of responding occurred when continuous response cost was made equal to reinforcement.
AVTA: A DEVICE FOR AUTOMATIC VOCAL TRANSACTION ANALYSIS1
Authors: Cassotta Louis , Feldstein Stanley , Jaffe Joseph
Published: March 2006

The Automatic Vocal Transaction Analyzer was designed to recognize the pattern of certain variables in spontaneous vocal transactions. In addition, it records these variables directly in a machine‐readable form and preserves their sequential relationships. This permits the immediate extraction of data by a digital computer. The AVTA system reliability has been shown to be equal to or better than that of a trained human operator in uncomplicated interaction. The superiority of the machine was demonstrated in complex interactions which tax the information processing abilities of the human observer.
Identification of nitrate sources in groundwater by δ15Nnitrate and δ18Onitrate isotopes: a study of the shallow Pleistocene aquifer in the Jericho area, Palestine
Authors: Khayat Saed , Geyer Stefan , Hötzl Heinz , Ghanem Marwan , Ali Wasim
Published: March 2006

This study describes the impact of septic tanks on the groundwater quality of the shallow Pleistocene aquifer in Jericho area, Westbank, Palestine. Septic tanks are widely used for storage and disposal of sewage in the populated and agricultural city of Jericho. Routine hydrochemical tests for groundwater quality performed for several years identified the problem of a gradual nitrate increase, without pinpointing its definite sources. The geological formations of the Jericho area and the shallow nature of the Pleistocene aquifer, together with the mechanism of recharge, make the groundwater in this aquifer highly susceptible to contamination, particularly along sewers. The lithology of the Samara (high hydraulic conductivity) and the Lisan formation (low conductivity but increased infiltration along fractures) promote easy seepage of agricultural and anthropogenic inputs into the groundwater. Nitrate concentrations are elevated near septic tanks and animal farms, with nitrate values exceeding 74 mg/L. δ15Nnitrate and δ18Onitrate signatures suggest sewage and manure as the main sources of high nitrate concentration in the groundwater. Samples taken during the end of the dry season indicate that a slight denitrification in the aquifer.
Benthic cyanobacterial assemblages as indicators of nutrient enrichment regimes in a Spanish river
Authors: Perona Elvira , Mateo Pilar
Published: March 2006

The relationships between cyanobacterial abundance and the physical and chemical characteristics of waters were studied to identify the environmental variables responsible for the changes in species composition observed in a river characterized by variations in water quality. Principal component analysis showed that some communities had significantly different species composition and relationships with environmental variables than others. These analyses allowed us to identify indicator species with contrasting responses to nutrient conditions. One of the four cyanobacterial groups distinguished in the analysis was negatively correlated with variables related to aspects of water disturbance, including nutrients. The results indicate that the eutrophication gradient structured species composition and affected cyanobacterial community distribution. Since organisms have an integrating response to their environment, the use of cyanobacterial assemblages to indicate eutrophication gradients could help in the assessment of water quality in aquatic ecosystems.
Characterization of the sources of thermal spring‐ and well water in Jordan by rare earth element and yttrium distribution and stable isotopes of H2O
Authors: Möller Peter , Dulski Peter , Salameh Elias , Geyer Stefan
Published: March 2006

Four types of thermal groundwater in Jordan were distinguished by Y and rare earth elements (REY) distribution patterns. Complementary to the stratigraphic origin of water in springs or of wells, REY patterns identify either recharge areas covered by basalt, limestones or sandstone, or interaction with basalt‐limestone contact zones. This hydrochemical grouping does not always correspond with “common geological knowledge” of the aquifer lithology of the thermal water. Therefore, comparison of the hydrochemical signatures of REY patterns and the lithological source of water yield insight into transaquifer flow. Out of 44 analysed groundwater, 18 indicated down‐ and 3 upflow of water the latter due to step faults near the Rift system. During transaquifer flow REY patterns of groundwater from basalts and gypsum beds or gypsum‐cemented sandstones are not changed by subsequent interaction with limestones, whereas in groundwater originating from dissolution of chalk and limestones REY patterns are adjusted to those typical for gypsum‐bearing sediments. Cross plots of δ18O vs. δ2H reveal essentially two trends. The main trend of water from limestone aquifers define a mixing line of past to recent meteoric water with negligible contributions of Pleistocene water. Some water from Eocene aquifers plot on the local Mediterranean meteoric water line, others plot together with water from sandstone aquifers at enhanced δ18O values due to hydrothermal overprinting.
Formation of monodisperse microbubbles in a microfluidic device
Authors: Xu J. H. , Li S. W. , Chen G. G. , Luo G. S.
Published: March 2006

The crossflowing rupture technique was first used in a microfluidic device to prepare microbubbles, and successfully prepared monodisperse microbubbles with polydispersity index (σ) values of <2%. The parameters affecting the microbubble‐formation process, such as two‐phase flow rates, continuous‐phase viscosity, surface tension, and surfactants were investigated. The microbubble‐formation mechanisms of the crossflowing rupture technique with those of the techniques of both flow‐focusing rupture and geometry‐dominated breakup were also compared. It was also found that the bubble size decreased with increasing continuous‐phase rate and its viscosity, while independent of surface tension. The different species of surfactants also influenced the microbubble‐formation process. Moreover, the bubble‐formation mechanism by using the crossflow rupture technique was different from the techniques of both hydrodynamic flow focusing and geometry‐dominated breakup. The microbubble‐formation process using the crossflowing rupture technique is controllable. © 2006 American Institute of Chemical Engineers AIChE J, 2006
Minimizing loss of sequence information in SAGE ditags by modulating the temperature dependent 3′ → 5′ exonuclease activity of DNA polymerases on 3′‐terminal isoheptyl amino groups
Authors: So Austin P. , Turner Robin F.B. , Haynes Charles A.
Published: March 2006

Numerous steps are required to prepare a sequencing library for serial analysis of gene expression (or SAGE) from an original mRNA sample. The presence of inefficiencies, however, can lead to a cumulative loss of sample during processing which can yield a library of short sequence tags (SSTs) that represents only a minute fraction of the original starting sample, potentially compromising the quality of the analysis and necessitating relatively large amounts of starting material. We show here that commonly observed higher molecular weight (HMW) amplification products observed following the PCR amplification of ditags are a direct result of the presence of HMW ligation products created during ditag formation. Using model tags, we demonstrate that the formation of these HMW ligation products becomes permissible following the release of the 3′‐terminal isoheptyl amine (3′‐IHA) from the SST during the fill‐in reaction with the Klenow fragment (KF) of DNA polymerase (DNAP) I and is mediated by its 3′ → 5′ exonuclease activity. We further show that the incorporation of SSTs into HMW ligation products can lead to a loss of sequence information from SAGE analysis, potentially skewing sequencing results away from the true distribution in the original sample. By modifying fill‐in conditions through the use of Vent® DNAP at 12°C and by including terminal phosphorothioate linkages within the SAGE adaptors to specifically inhibit exonucleolytic removal of the 3′‐terminal amine, we are able to maximize the yield of ditags and bypass the need for gel purification via PAGE following PCR. The modifications described here, combined with the modifications described previously by our group for adaptor ligation, ensure that the full sequence information content in SSTs derived from the transcriptome is preserved in the pool of amplified ditags prior to the creation of a SAGE library. © 2006 Wiley Periodicals, Inc.
A novel method for in vitro radiolabeling and testing enveloped viruses by phosphatidylethanolamine N‐methyltransferase and host cell‐specific binding
Authors: Gotoh Takeshi , Ando Nozomi , Kikuchi Ken‐Ichi
Published: March 2006

The present study developed a novel virus labeling and testing method, referred to as an envelope‐labeled virus assay (ELVA), in which virus envelope is labeled in vitro by the action of phosphatidylethanolamine N‐methyltransferase (PEMT) and tested through a host cell‐specific binding. A recombinant strain (vGFPuv) of Autographa californica multiple nuclear polyhedrosis virus (AcMNPV) and Spodoptera frugiperda (Sf‐9) insect cells were used as a model of viruses and host cells, respectively. The labeling mixture, which contained PEMT, [methyl‐3H]S‐adenosylmethionine (SAM), and a trace amount of detergent Triton X‐100, brought about little change in virus titer of vGFPuv on a 1‐h incubation, but was so toxic to Sf‐9 cells as to immediately cause cell death. After being incubated with vGFPuv, therefore, the labeling mixture was neutralized by adsorptive removal of PEMT and Triton X‐100 before Sf‐9 cells were contacted with the mixture to extract the virus. The Sf‐9 cells were then washed with a phosphate buffered saline (PBS), and lipid extracts with a 1% SDS solution were subjected to a liquid scintillation analysis for the determination of labeling efficiency. As a result, a significant amount of radioactivity was determined in the extracts, demonstrating the validity of ELVA for labeling and testing enveloped viruses. The conditions for the PEMT reaction and cell‐virus binding were examined, and the lower detection limit of AcMNPV by ELVA was found to lie in the order of 103 plaque forming unit (pfu) per milliliter. Since the labeling reaction and detection of virus are based on neither immunological nor genetic characteristics of virus, ELVA is also expected to be a convenient and comprehensive test of other enveloped viruses. © 2006 Wiley Periodicals, Inc.
Repeat resection of liver metastases
Authors: Farges O , Belghiti J
Published: March 2006

Can be effective
Can businesses move beyond efficiency? The shift toward effectiveness and equity in the corporate sustainability debate
Authors: Young William , Tilley Fiona
Published: March 2006

The aim of this paper is to articulate to a wider practitioner and academic audience the value and importance of moving the sustainable business agenda beyond the notion of eco‐ and socio‐efficiency. This in itself is not a new development in the sustainable business literature. What are emerging are integrated models of corporate sustainability that link together the six criteria that a sustainable business will need to satisfy, namely eco‐efficiency, socio‐efficiency, eco‐effectiveness, socio‐effectiveness, sufficiency and ecological equity. At this stage these new models of corporate sustainability need further theoretical development, taking corporate sustainability beyond the business case (eco‐efficiency) towards an integrated approach that links in the social and natural cases. A new model for sustainable entrepreneurship is presented and discussed in the context of a social entrepreneur case study. Copyright © 2006 John Wiley & Sons, Ltd and ERP Environment.
Sustainability, accountability and corporate governance: exploring multinationals' reporting practices
Authors: Kolk Ans
Published: March 2006

Recent years have seen a rapid increase in accountability pressures on particularly large global companies. The increased call for transparency comes from two different angles, which show some (potential) convergence in terms of topics and audiences: accountability requirements in the context of corporate governance, which expand to staff‐related, ethical aspects; and sustainability reporting that has broadened from environment only to social and financial issues. This article examines to what extent and how current sustainability reporting of Fortune Global 250 companies incorporates corporate governance aspects. Many multinationals, particularly in Europe and Japan, have started to pay attention to board supervision and structuring of sustainability responsibilities, to compliance, ethics and external verification. While detailed disclosures are not yet common, some notable practices can be found. Underlying dilemmas and complexities for managers in dealing with accountability to shareholders and stakeholders, and the role of auditors, are indicated. Copyright © 2006 John Wiley & Sons, Ltd and ERP Environment
Environmental policy and innovations
Authors: Krozer Yoram , Nentjes Andries
Published: March 2006

The paper defines and uses the concepts environmental policy cycle and innovation cycle and explores the links between the two in search for an environmental policy that creates incentives for innovation in environmental technology. We conclude that key factors are shortening the period the bureaucracy takes for preparing new environmental requirements, transparency and consistency of bureaucratic and political decision‐making and fast and strict implementation with environmental policy instruments that give pollution sources freedom in their choice of suitable technology. Economic instruments provide strong incentives for innovation because they speed up implementation. Large R&D subsidies may be needed to make technology development profitable under the conventional policy of direct regulation by emission standards and regulation by way of covenants. Copyright © 2006 John Wiley & Sons, Ltd and ERP Environment.
Managerial attitudes toward environmental management within Australia, the People's Republic of China and Indonesia
Authors: Cummings Lorne S.
Published: March 2006

This study presents a survey of the attitudes of corporate managers and managerial students across Australia, the People's Republic of China and Indonesia toward 18 key contemporary environmental management issues. The study sought to explore whether respondents from these countries, characterized by differing levels of development, also differ in their attitude toward environmental management. Results indicated that, despite age being a moderating factor, significant differences did exist between the 676 country respondents on 15 of the 18 questions. Contrary to expectations, Australian respondents were more cautious of supporting a forthright view on environmental issues, whilst Chinese respondents favoured a more centralized approach to decision making regarding the environment. The results lend marginal support to the new environmental paradigm (NEP), but also to the radicalization of environmental issues and age as a possible influence on respondent beliefs. Copyright © 2006 John Wiley & Sons, Ltd and ERP Environment.
Engaging Hong Kong businesses in environmental change: drivers and barriers
Authors: Studer Sonja , Welford Richard , Hills Peter
Published: March 2006

Hong Kong's businesses have been slow to embrace environmental management principles, particularly in the SME sector. This article analyses key barriers and incentives to engaging Hong Kong businesses with voluntary environmental initiatives and compares their relevance for companies of different sizes. As in other countries, SMEs show a much lower uptake of such activities than larger companies. Their approach towards environmental management is predominantly reactive, and legislation remains the key driver for engaging them with environmental change. Inadequate government policy and support, societal attitudes and corporate culture all contribute significantly to the comparatively poor development of corporate environmental management among Hong Kong companies. As long as most SMEs regard voluntary environmental activities as costly and unnecessary ‘extras’ that endanger their competitiveness and detract resources from their core business without offering any tangible benefits, fundamental improvements in their environmental performance will be difficult to achieve. Copyright © 2006 John Wiley & Sons, Ltd and ERP Environment.