Periocular fibrosarcoma with lipogranulomatous conjunctivitis in a cat.

A 9-year-old, female spayed domestic short-haired cat was presented with a 4-year history of bilateral lipogranulomatous conjunctivitis (LGC), which was confirmed via histopathology. Thirteen months following the initial biopsy, the cat was presented with a rapidly progressive mass lesion of the palpebral conjunctiva of the right eye. A surgical debulking, followed 1 month later by exenteration after marked regrowth of the mass confirmed fibrosarcoma. This case report is the first to describe a cat with chronic bilateral LGC that later developed a unilateral fibrosarcoma within the eyelid tissue of the right eye. Fibrosarcoma should be considered a differential in any cat with chronic LGC that develops a rapidly progressive mass in the eyelid.

Selective attention in dairy cattle.

In a replication of Reynolds (1961), two cows learned to discriminate between compound stimuli in a forced choice procedure where pushing through a one-way gate marked with a red cross (S+) gave access to food. Pushing through a one-way gate marked with a yellow triangle (S-) gave no access to food. To investigate whether shape or colour was controlling behaviour, probe tests varied either the shape or the colour of the stimuli (e.g., a red vs. a yellow cross, and a red cross vs. a red triangle). Results suggested control by colour rather than shape, as the gate marked with the red stimulus was chosen more than the gate marked with the yellow stimulus regardless of stimulus shape, and when two shapes of the same colour (either red or yellow) were presented, cows chose both equally. Further probe tests with painted red, white, and yellow stimuli showed that the cows had learned to avoid yellow rather than to approach red, suggesting discriminative behaviour was controlled by the colour of the negative stimulus and not by either aspect of the positive stimulus. It is not clear why the negative stimulus was more salient, but it may reflect a tendency for cows to learn to avoid farm handling practices which involve mainly negative stimuli.

Object/picture recognition in hens.

Two experiments examined whether hens, Gallus gallus domesticus, would respond to photographs in the same way they do to the real objects depicted in the photographs. Experiment 1 assessed whether hens transferred a discrimination of differently coloured three-dimensional objects to two-dimensional photographs of those objects, and vice versa. All hens learned to discriminate between the stimuli and showed transfer to the alternative stimuli when the colour cues were present. In Experiment 2 transfer with stimuli that differed in shape only was examined. It was found that only three of the six hens learned to discriminate the stimuli to any degree, and that these three hens did not transfer this discrimination to the alternative stimuli. It was also found that previously learning an object discrimination did not aid the hens in learning to discriminate between photographs of the objects. These data suggest that the hens did not respond to the objects depicted in pictures in the same way they did to the real objects. The authors argue it cannot be assumed that all animals respond to two-dimensional pictures of stimuli in the same way as they do to the real three-dimensional stimuli and this should be established before researchers use two-dimensional stimuli as representatives of real world stimuli.

Knowledge and practice of occupational infection control among healthcare workers in Jamaica.

OBJECTIVE: To assess the knowledge, compliance and practice among healthcare workers of occupational infection control at two hospitals in Jamaica. METHODS: Employing a cross-sectional study design, medical personnel (physicians and nurses) at two hospitals in Jamaica, were studied, utilizing a structured questionnaire consisting of 14 items to collect the data. RESULTS: Participants considered the following fluids, not blood stained, high risk for HIV transmission: breast milk (79%), saliva (14%), urine (27%), pleural fluid (53%), CSF (55%), synovial fluid (37%), faeces (27%), peritoneal fluid (53%) and vomitus (21%). The respondents estimated the risk of transmission of infection after a needlestick injury from a patient with: HIV, mean 22.5%, HB, 34% and HCV, 26%. Needles for drawing blood were identified as having the highest risk for transmission of infections in 63%. The following precautions were adhered to all the time: wearing gloves (38%), not re-sheathing needles (22%), not passing needles directly to others (70%), properly disposing of sharps (86%) and regarding patients' blood and other high risk fluid as potentially infected (62%). Post exposure, 43% indicated bleeding/squeezing the NSI site as the initial first-aid procedure, washing with soap and water (29%) and irrigating the area with water (20%). CONCLUSIONS: Healthcare workers are aware of the risk of transmission of infection, however compliance with universal precautions was inadequate. An improvement in knowledge and practice with clear guidelines are needed and a comprehensive programme to educate HCWs regarding compliance with universal precautions is urgently required.

Prevalence of needlestick injuries and other high risk exposures among healthcare workers in Jamaica.

OBJECTIVE: To assess the prevalence of needlestick injuries (NSIs) and other high risk exposures among healthcare workers at two hospitals in Jamaica. METHODS: Employing a cross-sectional study design, medical personnel (physicians, nurses) at two hospitals in Jamaica, were studied, utilizing a structured questionnaire consisting of 14 items to collect data on needle stick injuries and other injuries. RESULTS: There were 67 needlestick injuries in 47 persons. Of those sustaining an injury, 52% of physicians and 40% of nurses had NSIs. Re-capping needles accounted for 21% of injuries, various minor procedures, 21%, injury during surgery, 19.4% and taking blood, 12%. In those sustaining NSIs, 47% were reported and 26% of reported cases received counselling. Appropriate blood tests were performed on 34% and post-exposure prophylaxis (PEP) for HIV was administered to 30%. Hollow bore needles caused 47.8% of injuries, 25.4% occurred with suture needles and 19.4% with intravenous branulas. Other occupational exposure was reported by 31%, including blood on hands and other body parts 39%, blood to face and eyes, 18%, splashed with liquor, 18%, splashed with bloody fluid, 11% and contact with vomitus and urine in eye, 4%. CONCLUSION: Needlestick injuries and other high risk exposures were high; incident reporting and post exposure management were inadequate. A comprehensive programme to address factors that contribute to the occurrence of NSIs and other occupational exposures is urgently needed.

An investigation of colour discrimination with horses (Equus caballus).

The ability of four horses (Equus caballus) to discriminate coloured (three shades of blue, green, red, and yellow) from grey (neutral density) stimuli, produced by back projected lighting filters, was investigated in a two response forced-choice procedure. Pushes of the lever in front of a coloured screen were occasionally reinforced, pushes of the lever in front of a grey screen were never reinforced. Each colour shade was randomly paired with a grey that was brighter, one that was dimmer, and one that approximately matched the colour in terms of brightness. Each horse experienced the colours in a different order, a new colour was started after 85% correct responses over five consecutive sessions or if accuracy showed no trend over sessions. All horses reached the 85% correct with blue versus grey, three horses did so with both yellow and green versus grey. All were above chance with red versus grey but none reached criterion. Further analysis showed the wavelengths of the green stimuli used overlapped with the yellow. The results are consistent with histological and behavioural studies that suggest that horses are dichromatic. They differ from some earlier data in that they indicate horses can discriminate yellow and blue, but that they may have deficiencies in discriminating red and green.

Critical influences affecting response to various treatments in young children with ADHD: a case series.

BACKGROUND: While the use of stimulant medication as a treatment for children with attention deficit hyperactivity disorder (ADHD) has been the most studied therapy in child psychiatry, there is debate about its use with young children. This study describes a series of cases seen in a normal clinical context, treated with one of four different treatment programmes. METHODS: Sixteen pre-school children diagnosed with ADHD and their parents were randomly assigned to receive one of four treatments: (1) 0.3 mg/kg methylphenidate, parent training programme; (2) 0.3 mg/kg methylphenidate, parent support programme; (3) placebo medication, parent training; and (4) placebo medication, parent support. Changes were assessed at the individual level, using clinical observations, parent and teacher rating scales and measures of parenting and family factors. RESULTS: Children were more likely to improve when the treatment involved at least one active component (medication or parent training). However, there was notable variability in individual parental and child participants' responses to all treatment conditions, indicating the importance of interactions between treatment variables and other factors. CONCLUSIONS: Findings are discussed within the framework of a transactional model, and inferences are drawn about the limitations of the idea that there is a 'best treatment' that is universally applicable.

Establishing and maintaining an operant research facility with brushtail possums (Trichosurus vulpecula).

The common brushtail possum (Trichosurus vulpecula) is a readily accessible marsupial that has been shown to adapt relatively well to captivity. The aim of this paper is to outline the husbandry procedures, experimental equipment, and methodologies used successfully within our possum colony since 1995.

Determination of auditory thresholds in the brushtail possum (Trichosurus vulpecula).

The auditory abilities of the brushtail possum (Trichosurus vulpecula) have been measured by cochlear potential readings, but no behavioural determinations of their auditory abilities have been published. Six experimentally naive possums were trained to perform a two-response conditional discrimination between the presence and absence of an 880-Hz tone (at 80 dB). All six possums readily learned this task. The behavioural threshold for this tone was determined using a modified tracking procedure and found to be similar to that reported using cochlear microphonic potentials. One concern with the current method was the communal nature of the experimental environment so a further threshold determination in a sound-attenuating chamber was conducted. No substantial difference was noted between the results obtained in the two threshold determinations. The success of the current method means that a full, behavioural audiogram for the brushtail possum, which would complement the existing cochlear potential data, is now possible.

Resurgence: the role of extinction.

Three hens were trained to door push and three were trained to head bob using food as the reinforcer (Behaviour 1 training). A period of extinction followed. Each hen was then trained to perform the other behaviour (Behaviour 2) and this was followed by seven sessions of extinction. This whole sequence was repeated six times, with two sessions of extinction following Behaviour 1 training. Over the repeated extinction conditions there were decreases in responding early in extinction, for both Behaviours 1 and 2, compared with the first condition. Behaviour in the later extinction sessions could be studied for Behaviour 2 only, and it was found to increase relative to the first condition, over repeated extinction conditions. The occurrence of Behaviour 1 during the extinction following the training of Behaviour 2, that is the resurgence of Behaviour 1, both over the whole of and in the first session of each extinction phase, was variable and tended to increase over these six conditions. Thus it is possible to study resurgence using a within-subject design but the effect of repeated extinction conditions needs to be considered. The period of extinction immediately following Behaviour 1 training was then increased to nine sessions for two replications of the whole sequence. This was followed by two repeats of the sequence with no sessions of this extinction and then by another repeat, with nine sessions of this extinction phase. Over these five conditions the total resurgence of Behaviour 1 was generally greater when there were no sessions of extinction immediately following Behaviour 1 training, than when there were nine sessions. This result was more marked for the resurgence of Behaviour 1 in the first session of the extinction of Behaviour 2. Thus, these data support the hypothesis that the resurgence of Behaviour 1 is the result of the prevention of the extinction of Behaviour 1 by training Behaviour 2. At a similar point in extinction, the number of occurrences of Behaviour 1 in its own extinction was not significantly different from the number of occurrences of Behaviour 1 during the extinction of Behaviour 2. This fails to support the hypothesis that resurgence is induced by the extinction of Behaviour 2.

Reinforcer efficacy in a delayed matching-to-sample task.

Five domestic hens were exposed to a delayed matching-to-sample task. Conditions 1, 5, and 8 were variable-delay conditions in which five delays (0.25, 1, 2, 4, and 8 s) from the red or green sample to the presentation of the red and green comparison stimuli were presented a number of times during each session. In the fixed-delay condition (Condition 3), each delay was presented for 15 sessions under a Latin square design across birds. When improvements in accuracy across the variable-delay conditions are taken into account, the data were similar under both the variable and fixed delays. In Conditions 2, 4, 6, and 7 sample-reinforcer intervals were held at 8, 8, 4, and 2 s, respectively, while sample-choice intervals were varied within these during each session. With increasing sample-reinforcer interval, both initial discriminability (i.e., with sample-choice delay = 0) and rate of decrement in discriminability decreased. Although the former would be predicted if accuracy depends of the average sample-reinforcer interval, the latter would not. These data show that increasing the sample-choice interval had less effect on matching accuracy than increasing the sample-reinforcer interval did.

Behavior analysis and farm animal welfare.

This article demonstrates that there is a role for behavior-analytic techniques in the area of farm animal welfare and provides examples of the kinds of work that can be done. Behavior-analytic procedures, specifically those used in the study of psychophysics, preference, and demand, can provide answers to three questions people concerned with the welfare of farm animals are likely to ask: What can the animals detect? What do they like and dislike? What will they work to attain or preserve? Such information certainly is necessary for making reasonable decisions about animal welfare, although it is not sufficient in and of itself.

Concurrent schedule performance in domestic goats: persistent undermatching.

Performance of nine domestic goats responding under concurrent variable-interval variable-interval schedules of food delivery was examined, with results analyzed in terms of the generalized matching equation. Substantial undermatching of response and time allocation ratios to obtained reinforcement ratios was evident. Post-reinforcement pause time ratios approximately matched obtained reinforcement ratios. Subtracting these times from total time allocation values yielded net time allocation ratios, which undermatched obtained reinforcement ratios to a greater degree than whole-session time allocation ratios. Slopes of regression lines relating behavioral outputs to environmental inputs characteristically were below 0.6, which is similar to previous findings in dairy cows tested under comparable conditions.

Demand curves for food in hens: Similarity under fixed-ratio and progressive-ratio schedules.

Demand curves were generated for five domestic hens under progressive-ratio 5 schedules of food delivery and under fixed-ratio schedules of food delivery that began at fixed-ratio 5 and were incremented by 5 each session. All sessions ended after 10 consecutive minutes without a response. Although response rates at a given ratio were higher under the progressive-ratio schedule, all hens completed higher ratios under the fixed-ratio schedule. Similar, but not identical, demand curves were generated under progressive-ratio and fixed-ratio schedules. Under both schedules, consumption (reinforcers earned) decreased as cost (ratio size) increased. Data generally were well described by an equation in which elasticity of demand is constant, although an equation in which elasticity could vary accounted for slightly more of the variance.

Concurrent-schedule performance in dairy cows: persistent undermatching.

Performance of dairy cows responding under concurrent variable-interval variable-interval schedules of food delivery was examined, with results analyzed in terms of the generalized matching equation. In Experiment 1, bias measures indicated that crushed barley was preferred over meatmeal when these foods were available under the alternative schedules. For whole-session data, substantial undermatching of response and time-allocation ratios to obtained reinforcement ratios was evident. Postreinforcement pause time ratios approximately matched obtained reinforcement rates. Subtracting these times from total time-allocation values yielded net time-allocation ratios that undermatched obtained reinforcement ratios to a greater degree than did whole-session time-allocation ratios. In Experiment 2, substantial undermatching was evident when the same foods (hay for 2 cows, crushed barley for 2 others) were available under the alternative schedules. Food-related activities and other defined behavior not related to food were quantified by direct observation, and were found to occupy a substantial proportion (roughly 40% to 80%) of experimental sessions. Subtracting the time spent in these activities from the time allocated to each component schedule did not reduce the degree of undermatching obtained. Across all conditions in both experiments, slopes of regression lines relating behavioral outputs to environmental inputs characteristically were below 0.6, which agrees with prior findings and suggests that, contrary to suggestions in the literature, undermatching in dairy cows is not the result of using different foods under alternative schedules or differential pausing under those schedules.

Concurrent schedules: Quantifying the aversiveness of noise.

Four hens worked under independent multiple concurrent variable-interval schedules with an overlaid aversive stimulus (sound of hens in a poultry shed at 100dBA) activated by the first peck on a key. The sound remained on until a response was made on the other key. The key that activated the sound in each component was varied over a series of conditions. When the sound was activated by the left (or right) key in one component, it was activated by the right (or left) key in the other component. Bias was examined under a range of different variable-interval schedules, and the applicability of the generalized matching law was examined. It was found that the hens' behavior was biased away from the sound independently of the schedule in effect and that this bias could be quantified using a modified version of the generalized matching law. Behavior during the changeover delays was not affected by the presence of the noise or by changes in reinforcement rate, even though the total response measures were. Insensitivity shown during the delay suggests that behavior after the changeover delay may be more appropriate as a measure of preference (or aversiveness) of stimuli than are overall behavior measures.

The differential outcomes effect: A demonstration in domestic chickens responding under a titrating-delayed-matching-to-sample procedure.

The differential outcomes effect refers to the increase in speed of acquisition or terminal accuracy that occurs in discrimination training when each of two or more discriminative stimuli is correlated with a different outcome (e.g. type of reinforcer). The present study demonstrated this effect in domestic hens exposed to a titrating-delayed-matching-to-sample procedure, under which correct responses increased (and incorrect responses decreased) the delay between the offset of a sample stimulus and the onset of two comparison stimuli. Colors of key illumination (red, green) were used as sample and comparison stimuli and correct responses resulted in 1- or 4-s food deliveries. When 1-s food deliveries consistently followed correct responses to one key color and 4-s food deliveries followed correct responses to the other key color, the maximum delay reached by the hens and their overall accuracy was significantly higher than when 1- and 4-s food deliveries were randomly arranged following correct responses to both key colors. These data constitute the first demonstration of the differential outcomes effect in chickens, and in any species evaluated under a titrating-delayed-matching-to-sample procedure.

Delayed matching-to-sample performance of hens: Effects of sample duration and response requirements during the sample.

Six domestic hens were trained under a delayed matching-to-sample procedure with red and green keylights as sample and comparison stimuli and a 1.5-s delay interval. The hens were trained to stop pecking the sample stimuli when a tone sounded. Duration of the sample stimuli (2 to 10 s) and the number of pecks required on the key on which these stimuli were presented (0 to 10) were altered across conditions. Both the response requirement on the sample key and the duration of sample presentations affected accuracy. These findings are in agreement with those of earlier studies using other species and somewhat different procedures.