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PubMed2004

Quantitative data on training new world primates to urinate.

This study assessed the effectiveness of operant conditioning in training three species of captive callitrichid primates (Leontopithecus rosalia, Callithrix geoffroyi, and Saguinus imperator) to urinate on demand. There were three goals to the study: 1) to develop a system for quantitatively assessing positive reinforcement training; 2) to ascertain whether or not positive reinforcement techniques can be used to train callitrichid monkeys to urinate on demand, and if so, how many training sessions are required; and 3) to determine the effect on urination behavior of the trainer entering the cage to collect a urine sample. Positive reinforcement with a continuous reinforcement schedule was used to capture a natural behavior: urination. Training sessions (30 min each) were conducted at dawn thrice weekly during five consecutive phases: habituation, control, training (animals were rewarded for urinating), maintenance (animals had reached a defined training criteria and continued to be rewarded for urinating), and collection (animals were rewarded for urinating, and the trainer entered the cage to collect the sample). The numbers of 30-min training sessions required to train the three monkey species (L. rosalia, C. geoffroyi, and S. imperator) were five, six, and eight, respectively. For the three species, the mean number of urinations per animal was significantly greater during the training, maintenance, and collection phases compared to the control phase. However, the three species differed significantly in the manner in which the rates of urination changed across the five phases. A higher proportion of subjects urinated during the training, maintenance, and collection phases compared to the control phase. Latency to first urination varied significantly across the five phases, with significantly reduced latencies to urinate during the training, maintenance, and collection phases compared to the control phase. The entry of the trainer into the cage to collect the urine sample did not appear to alter urination behavior. We demonstrate that operant conditioning techniques, which typically incur minimal cost, time investment, and disturbance, can be used to increase the quantity of urine samples collected for physiological analysis, the proportion of animals that urinate, and the speed of sample collection.

Animals↗
PubMed2003

NMDA-dependent and NMDA-independent neural processes in the bicucculline-disinhibited motor cortex of the cat during the acquisition and reproduction of a conditioned paw-on-support placing reflex.

Neuron activity was recorded in the motor area of the cat cortex during acquisition of an operant conditioned reflex consisting of placing the forepaw on a support in conditions of local disinhibition by spontaneous diffusion of the GABA(A) receptor blocker bicucculline from the recording micropipette. The conditioned signal was electrical stimulation of the parietal cortex with a train of 3-5 impulses. Addition of 2-amino-5-phosphopentanoic acid (APV), an NMDA glutamate receptor blocker, led to disappearance of the secondary excitatory components (in the poststimulus interval 30-120 msec) from neuronal responses in the disinhibited cortex both to the "indifferent" (before training) and the conditioned stimulation of the parietal cortex, while excitatory reactions associated with elevation and placing of the paw on the support showed no significant change in the presence of APV. Acquisition of the operant conditioned reflex was accompanied by an increase in the amplitude (p < 0.006) and duration (p < 0.00002) of secondary responses and decreases in their latent periods (p < 0.00002). In some cases--in fixed conditioned reflexes--secondary responses to conditioned stimulation in the disinhibited cortex were transformed into trains of epileptiform discharges. The hypothesis that changes in neuronal reactions in the disinhibited cortex during learning are based on increases in the efficiency of horizontal (collateral) connections between pyramidal neurons in layers II and III of the cortex is discussed.

Animals↗
PubMed2004

PCDD/F TEQ indicators and their mechanistic implications.

Stack gas samples from two incinerator facilities with different operating conditions were investigated to understand how indicators of toxic equivalency (TEQ) from among the 210 polychlorinated dibenzo-p-dioxin/furan (PCDD/F) isomers varied. This effort was motivated by the need to find more easily monitored indicator compound(s) of TEQ and to reconcile the varying indicator compounds reported in the literature. The measured isomer patterns were compared with those expected from known formation mechanisms to identify the dominant mechanism(s) and explain why certain compounds are relevant TEQ indicators. Despite differences in the facility types and operating conditions, a common pattern was found for the highly chlorinated (4Cl and higher) PCDDs/Fs. A combination of chlorination/dechlorination reactions as the dominant formation mechanism for PCDF was consistent with the observed isomer patterns, whereas condensation reactions of phenolic precursors appeared to be responsible for PCDD formation. PCDF isomers, ratherthan the PCDD isomers, were more closely related to the TEQ measure, likely because the chlorination mechanism favors 2,3,7,8-Cl-substitution more than the phenol condensation mechanism. Unlike highly chlorinated PCDD/F isomer patterns, less chlorinated PCDD/F patterns (especially, mono- and di-CDF) were sensitive to operating conditions and facility type. Competing formation mechanisms were inferred from the variation of observed isomer distribution patterns; this sensitivity resulted in relatively low correlations of these isomers with PCDD/F TEQ values. This suggests that any use of the low-chlorinated compounds as TEQ indicators for online monitoring processes are likely best suited for plant-specific, rather than universal, applications. In addition to many of the highly chlorinated (penta-CDF, hexa-, and heptaCDD/F) isomers being identified as strong TEQ indicators, 1 of 12 (8%), 5 of 17 (29%), and 5 of 28 (18%) of the separable tri-CDD, tri-CDF, and tetra-CDF isomers, respectively, were identified as strong (R2 > 0.7) TEQ indicators in both incinerators.

Air Pollutants↗
PubMed2005

Cyclical electrical field flow fractionation.

Cyclical electrical field flow fractionation (Cy/ElFFF) is demonstrated in a standard electrical field flow fractionation (ElFFF) channel for the first time. Motivation for the use of alternating current (AC) fields in a traditionally direct current (DC) technique are discussed. The function of the system over a wide range of operating conditions is explored and challenges associated with various operating conditions reported. Retention of polystyrene nanoparticle standards is accomplished and the effect of varying parameters of the applied field, such as voltage and frequency, are explored. The first separations using this technique are demonstrated. The experimental results are compared to analytical models previously reported in the literature. The general trend of the experimental results is similar to those predicted in theoretical models and possible reasons for discrepancies are elucidated. Suggestions are made for improving the separation and analysis method, and possible applications explored.

Electrophoresis↗
PubMed2002

[Predicting low NOx combustion property of a coal-fired boiler].

More attention was paid to the low NOx combustion property of the high capacity tangential firing boiler, but the NOx emission and unburned carbon content in fly ash of coal burned boiler were complicated, they were affected by many factors, such as coal character, boiler's load, air distribution, boiler style, burner style, furnace temperature, excess air ratio, pulverized coal fineness and the uniformity of the air and coal distribution, etc. In this paper, the NOx emission property and unburned carbon content in fly ash of a 600 MW utility tangentially firing coal burned boiler was experimentally investigated, and taking advantage of the nonlinear dynamics characteristics and self-learning characteristics of artificial neural network, an artificial neural network model on low NOx combustion property of the high capacity boiler was developed and verified. The results illustrated that such a model can predicate the NOx emission concentration and unburned carbon content under various operating conditions, if combined with the optimization algorithm, the operator can find the best operation condition of the low NOx combustion.

Carbon↗
PubMed2005

Sustainable management of leakage from wastewater pipelines.

Wastewater pipeline leakage is an emerging concern in Europe, especially with regards to the potential effect of leaking effluent on groundwater contamination and the effects infiltration has on the management of sewer reticulation systems. This paper describes efforts by Australia, in association with several European partners, towards the development of decision support tools to prioritize proactive rehabilitation of wastewater pipe networks to account for leakage. In the fundamental models for the decision support system, leakage is viewed as a function of pipeline system deterioration. The models rely on soil type identification across the service area to determine the aggressiveness of the pipe environment and for division of the area into zones based on pipe properties and operational conditions. By understanding the interaction between pipe materials, operating conditions, and the pipe environment in the mechanisms leading to pipe deterioration, the models allow the prediction of leakage rates in different zones across a network. The decision support system utilizes these models to predict the condition of pipes in individual zones, and to optimize the utilization of rehabilitation resources by targeting the areas with the highest leakage rates.

Decision Making↗
PubMed1983

Alcoholism. The evolution of a behavioral perspective.

Behavioral approaches to understanding the etiology of alcoholism represent a divergence from traditional biomedical and psychodynamic models. The behavioral perspective subsumes a number of diverse conceptual models that share a common emphasis on the interplay between environmental forces and the response of the organism (S-R model). Yet these models--classical conditioning, drive reduction, and operant conditioning--offer different procedural paradigms and explanatory mechanisms. Through consistent application of the scientific method, certain behavioral principles from these models have survived empirical validation and continue to enrich our understanding of alcoholism. This chapter reviews these models and their attendant empirical findings, from both animal and human research, as they pertain to the etiology of alcoholism. The cognitive-behavioral approach, a recent product of this evolutionary development, focuses on cognitive processes that mediate stimulus-response relationships. The cognitive-behavioral model provides a comprehensive account of both the acquisition and maintenance of problem drinking and is discussed in some detail.

Alcoholism↗
PubMed1993

[Radiometric survey during hemodynamic studies with "Siemens Angioskop D" equipment].

PURPOSE: To provide data for professional specialized in these subjects, contributing to minimize their exposure radiation dosage. METHODS: We made a radiometric survey using a ionization chamber to check the exposure rate in several places in the examination's room to different operational conditions of X-ray equipment. RESULTS: The operational conditions on which we have gotten the highest scatter X-ray rate were: image intensifier with 17cm of diameter for left anterior oblique projection (45 degrees) and image intensifier with 27cm of diameter for perpendicular beam to the patient (0 degrees). During fluoroscopy and cinefilm mode we have got average reduction of 40% for scatter X-ray using the image intensifier of 27 cm of diameter. During the cinefilm the dose rates were 23 times bigger than the dose rate in fluoroscopy mode. CONCLUSION: An analysis of results show that the choice of X-ray entrance angle as well as the diameter of image's intensifier during the cinefilm and fluoroscopy mode change significantly the occupational exposure dosages. Considering that in this kind of procedure, physicians and assistants spent long time close to the patient, they should have special concern to observe the technical condition more appropriate as well as to make use of all protection devices to minimize the personnel dosage.

Cardiology↗
PubMedDate not supplied

Propofol versus isoflurane for endoscopic sinus surgery.

PURPOSE: A previous retrospective study reported that propofol anesthesia decreased bleeding during endoscopic sinus surgery compared with isoflurane. We performed a prospective study to compare the effects of propofol versus isoflurane on measured blood loss and the surgeon's subjective assessment of operating conditions during endoscopic sinus surgery. PATIENTS AND METHODS: After receiving institutional review board approval and written informed consent, 56 patients undergoing endoscopic sinus surgery were randomly assigned to receive propofol (n = 30) or isoflurane (n = 26) supplemented with nitrous oxide-oxygen and alfentanil. Blood loss was calculated from the hemoglobin concentration in suction canisters. One surgeon, who was blinded to the anesthetic agent, performed every procedure and assessed bleeding as follows: 1, no bleeding; 2, modest bleeding; 3, bleeding interfering with operating conditions and cause for an agent switch; and 4, intolerable bleeding requiring a change in surgical plan. Results were compared in the two anesthetic groups using chi-squared test, unpaired t-test, Mann-Whitney Utest, and a permutation test. A P of .05 was considered significant. RESULTS: Mean bleeding scores were less over time (P = .02) with propofol anesthesia, particularly in surgery in the ethmoid and sphenoid sinuses (P = .03), and the proportion of patients with a mean score >2 was less in the propofol group (30% v 54%; P = .033). Time until discharge to home or to a limited stay in a hospital bed was also less in the propofol group (183 v 243 minutes; P = .019). CONCLUSION: In our study, surgical blood loss was the same for both anesthetic agents overall, but propofol appeared to offer an advantage in terms of subjective improvement in operating conditions, particularly in the ethmoid and sphenoid sinuses.

Adult↗
PubMed2000

[Column efficiency prediction of two dimensional chromatography by artificial neural network].

This paper used artificial neural network (ANN) modeling method to study the relationship between the column efficiency and the operating conditions. This method solved the problem that it is not easy to establish a quantitative model between the column efficiency and its main effecting factors using those traditional modeling methods, as the relationship is usually quite complex and non-linear in fact. The varied-pace BP (back-propagation) learning algorithm was adopted, and a three-layer weight-connected ANN model for a typical dual column system was established. The effective plate number representing the column efficiency acted as the output vectors, while the temperature of the pre-column, the temperature of the main column, the pressure difference between the columns and the vent rate acted as the input vectors. Then the model acquired was used to predict column efficiency (characterized by "effective plate number") under different operating conditions. The results showed that the model predicting value was in consistent with the value found. This work proved that ANN modeling method was suitable for the study on the relationship between the column efficiency of two-dimensional column chromatography system and the operating conditions.

Algorithms↗
PubMed1987

Dopamine and serotonin metabolism in brain sites ipsi- and contralateral to direction of conditioned turning in rats.

Concentrations of dopamine, serotonin, and some of their metabolites were analyzed by means of HPLC in brain samples obtained from rats operantly conditioned to turn in circles to obtain water reinforcement. In experiment 1 using Wistar rats, no differences in the levels of transmitters or metabolites were detected between brain samples (frontal cortex, ventral striatum, dorsal striatum, septum, amygdala, substantia nigra) from the hemispheres located ipsi- and contralateral to the direction of turning. A higher dopamine metabolism (indicated by higher metabolite/transmitter ratios) in ventral striatum, dorsal striatum, and amygdala was found after 15 min than after 5 min of turning in both hemispheres. A higher dopamine metabolism was found in water-deprived rats compared to nondeprived rats independently of whether or not deprived rats were trained to turn for water reinforcement. In two additional experiments, no differences in dopamine metabolism were found between the ipsi- and contralateral striatum of Wistar rats after 25 min and Sprague-Dawley rats after 10 min of operantly conditioned turning. The present results confirm that dopamine metabolism can change with different behavioral or physiological states; they do not support the hypothesis that conditioned turning is correlated with asymmetrical changes in the metabolism of dopamine or serotonin in the brain.

Animals↗
PubMed1997

Dorsal column but not lateral column transection prevents down-conditioning of H reflex in rats.

Operant conditioning of the H reflex, the electrical analogue of the spinal stretch reflex, in freely moving rats is a relatively simple model for studying long-term supraspinal control over spinal cord function. Motivated by food reward, rats can gradually increase or decrease the soleus H reflex. This study is the first effort to determine which spinal cord pathways convey the descending influence from supraspinal structures that changes the H reflex. In anesthetized Sprague-Dawley rats, the entire dorsal column (DC), which includes the main corticospinal tract, or the right lateral column (LC) was transected by electrocautery. Animals recovered quickly and the minimal transient effects of transection on the right soleus H reflex disappeared within 16 days. Beginning at least 18 days after transection, 12 rats were exposed to the HRdown-conditioning mode, in which reward was given when the H reflex of the right soleus muscle was below a criterion value. In seven LC rats exposed to the HRdown mode, the H reflex fell to 71 +/- 8% (mean +/- SE) of its initial value. In six of the seven, conditioning was successful (i.e., decrease to < or = 80%). These results were comparable with those previously obtained from normal rats. In contrast, in five DC rats exposed to the HRdown mode, the H reflex at the end of exposure was 106 +/- 12% of its initial value. In none of these rats was HRdown-conditioning successful. DC rats differed significantly from normal and LC rats in both final H reflex values and number successful. In five DC and three LC rats that continued under control conditions over 30-78 days, the H reflex at the end of the period was 98 +/- 4% and 100 +/- 8%, respectively, of its initial value, indicating that DC or LC transection itself did not lead to gradual increase or decrease in the H reflex. The results indicate that the DC, containing the main corticospinal tract, is essential for HRdown-conditioning, whereas the ipsilateral LC, containing the main rubrospinal, vestibulospinal, and reticulospinal tracts, is not essential. Combined with the known muscular specificity of conditioning, these results suggest that the main corticospinal tract is essential for HRdown-conditioning. The DC ascending tract might also be necessary. The respective roles of the DC descending and ascending tracts, and transection effects on HRup-conditioning and on the maintenance of both HRup- and HRdown-conditioning after they have occurred, remain to be defined.

Animals↗
PubMed1978

A behavioral analysis of complete unilateral section of the pyramidal tract at the medullary level in Macaca mulatta.

Ten Macaca mulatta monkeys were operantly conditioned to perform three motor paradigms designed to evaluate single and combination finger movements. Eight of these monkeys were retested after left medullary pyramidotomy; 2 monkeys underwent left medullary pyramidotomy prior to conditioning. All animals were tested for three years after operation. Monkeys with a completely sectioned medullary pyramid could, with time, perform difficult motor paradigms that required: (1) both individual and combination finger movements; (2) proximal upper extremity motor control; (3) thumb and index finger pincer grasp; and (4) the ability to preprogram and then execute a precision hand movement. The greater the extent of pyramidal tract destruction, the longer the time necessary for recovery of both discrete finger movement and pincer grasp, the greater the effort needed to attain recovery of hand function, and the weaker the affected musculature. The 2 animals in which pyramidotomy of at least 70% of the tract preceded efforts at operant conditioning learned and performed difficult motor paradigms. In all animals, neurological examination revealed that the most enduring and functionally most important deficit that interferes with hand function following pyramidotomy is loss of contactual hand orienting responses and failure of reflex sensorimotor adjustments.

Animals↗
PubMed2007

Systematic reviews of bladder training and voiding programmes in adults: a synopsis of findings on theory and methods using metastudy techniques.

AIM: This paper reports a comparison of four Cochrane systematic reviews on bladder training and voiding programmes for the management of urinary incontinence using metastudy descriptive techniques. It presents a synopsis of findings on theory and methods for interventions. BACKGROUND: From the mid-1970s bladder training, prompted voiding, habit retraining and timed voiding have been developed and form the basis of nursing practice for the management of urinary incontinence in adults in institutional and community settings. METHODS: A synopsis of four Cochrane systematic reviews was undertaken using metastudy techniques developed for qualitative research and has provided a discursive comparison and contrast of the selection and appraisal of primary research, meta-theory and meta-method. FINDINGS: All programmes share a therapeutic focus on voiding and the degree and active participation of the client and caregiver. Bladder training focuses on the restoration of continence, while prompted voiding, habit retraining and timed voiding focus on the avoidance of incontinence. Bladder training and prompted voiding share the two characteristics of cognitive behavioural modification and active client participation. Habit retraining and timed voiding pre-empt episodes and avoid incontinence using operant conditioning rather than modifying behaviour. Variability of methods and operational terminology makes comparison between studies difficult. Use of cognitive behavioural approaches and operant conditioning need to be better understood in relation to future theory, interventions and study design. Bladder training is aimed at people who are cognitively and physically able, while the other voiding programmes are mainly used with for people with cognitive and physical impairments reliant on caregivers. CONCLUSION: The theoretical approaches underpinning bladder training and voiding programmes, their components and suitability for patients need to be re-considered when designing future studies. There is a need for long-term follow-up in future studies. Future trials should adhere to recognized standards of good practice and incorporate outcomes from existing systematic reviews to enable future meta-analysis to be undertaken. Metastudy techniques for the synthesis of qualitative research provide useful methods for the descriptive synopsis of quantitative systematic reviews.

Adult↗
PubMedDate not supplied

Stress states in nuclear operators under conditions of shiftwork.

This study examined the stress states experienced by nuclear power operators at work under an existing shift system, time-on-shift effects and the manner in which these states may be moderated by achievement motivation and a sense of coherence. The results show an incidence of stress states during evening shifts and night-shifts in the operators, which are primarily characterized by increased distraction as well as by enhanced sleepiness and low irritability. The night-shift was found to be the most problematic one in terms of increased sleepiness and distractibility, and reduced alertness. An abrupt fall in alertness during the evening shift and a considerably increased distractibility at its end was observed. These facts, as well as the lack of recuperation from daily domestic activities and caring for children at the start of the shift, suggest that besides the night duty, the evening one also constitutes a serious challenge to operational safety at this nuclear facility. Correlations found between personality characteristics and sleepiness, distractibility and irritability, indicate personal resources as important modifiers of stress states. A narrowing in the effects of motivation and sense of coherence was found in the evening shifts and night-shifts. The results have practical implications for intentional modifications of personal resources at nuclear facilities.

Adult↗
PubMed1998

Conditioned visual flight orientation in Drosophila melanogaster abolished by benzaldehyde.

To study learning and memory of Drosophila melanogaster in the flight simulator, single flies are trained in an operant conditioning paradigm to avoid a course towards visual objects that are associated with heat. The results demonstrate that normal flies (wild-type "Berlin") can quickly learn to avoid the heat-associated objects and retain the memory. This allows us to further explore a recently communicated long-term effect of preimaginal benzaldehyde (BAL) influence on the association of visual objects with the aversive odor of BAL. Here we show that flies, exposed to BAL in the embryonic, larval or adult stage, do not accompany by a similar indifference to heat shocks. The flies are successfully trained to avoid the heat-associated visual patterns. It shows that the learning acquisition is not affected during the operant conditioning in the flight simulator. Neither object perception nor object discrimination is altered after exposure to BAL, as is shown by Fourier analysis. However, the test results after training show that exposure to BAL interferes directly with memory formation in Drosophila. It takes at least two generations of growth on the noncontaminated medium that the strain recovers fully from BAL-induced amnesia. The BAL treatment seems not only to affect the associative memory formation, but in addition the flies' development in general, as is indicated by prolonged developmental time. However, the impaired memory after BAL treatment in different stages seems to have nothing to do with an influence of BAL on the cAMP-level.

Adaptation, Physiological↗