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PubMed1988

The infant vocal-conditioning literature: a theoretical and methodological critique.

Most studies of operant conditioning of infant vocalization do not fully use the experimental-analysis-of-behavior methodology that behavioral researchers have developed to study operant phenomena. This could be a contributing factor in their failure to correctly operationalize the definition of reinforcement, severely limiting the amount of information they can provide about operant learning in infants. Furthermore, single-subject-design studies may be added to supplement or replace group experimental designs in the study of infant vocal conditioning if we are to recognize the different learning processes that affect infant learning. Finally, single-subject experimental designs may be crucial to the development of an effective technology of early language intervention.

Child Language↗

PubMed1991

The effects of ethanol initiation procedures on ethanol reinforced behavior in the alcohol-preferring rat.

Rats from the alcohol preferring (P) line developed at Indiana University were initiated to self-administer ethanol orally without food or water restriction using either a sucrose-fading or a secondary-conditioning procedure. Following initiation, they were tested under a variety of operant conditions to examine the ability of ethanol to reinforce lever pressing behavior. Regardless of initiation procedure, the animals maintained lever pressing behavior with ethanol reinforcement, even at ethanol concentrations as high as 40% (v/v). Slightly higher daily session intakes (g/kg) were found at the higher ethanol concentrations following the secondary-conditioning initiation procedure compared with the sucrose-fading technique. When both ethanol and water were concurrently available, the rats showed a high preference for ethanol reinforcement. When varying concentrations of sucrose were substituted for water, the amount of ethanol ingested decreased as the concentration of the alternative sucrose increased. However, if the response requirement for the sucrose was substantially greater than that for ethanol, the rats shifted their responding to the lever associated with ethanol presentation. The results are discussed in relation to prior work using similar procedures with Long-Evans non-selected rats and with the alcohol non-preferring (NP) rat line.

Alcohol Drinking↗

PubMed1982

[Long-term observation and results following trapeziectomy in idiopathic thumb carpometacarpal joint arthrosis].

Numerous, complicated and expensive operative techniques have been described in recent years for the treatment of osteo-arthritis of the thumb. Aetiologically, the idiopathic form of this disability is the most frequent and effects especially women older than 50 years. A longtime follow-up (21/2 to 101/2 years) after trapeziectomy allowed critical assessment of the various operative procedures and a realistic evaluation of the removal of the trapezium. In this group of patients the examination of mobility and pain are the most important aims, followed by strength and appearance. Assessment of pain, mobility strengths of pinch and radiological findings--including the very important functional roentgenograms--showed that trapeziectomy, with or without tendon interposition, represents the method of choice. All patients, in all parameters, showed a significant improvement in comparison with the pre-operative condition. A detailed pre-operative clinical and radiological examination enables us to appreciate correctly the osteo-articular, capsulo-ligamentous and muscular conditions of the first ray in the hand. This allows us to supplement the trapeziectomy with soft tissue procedures (e.g. plication of the capsule, disinsertion of adductor pollicis tendon, etc.) which improve the final results, especially with respect to strength. The assessment of the longterm results after trapeziectomy demonstrated 50% very good, 45% good and 5% fair results.

Aged↗

PubMed1976

The localization of precancerous changes and carcinoma after previous gastric operation for benign condition.

Sixty-five patients operated on for a benign gastric condition showed at re-operation in 9 cases precancerous changes, in 22 cases carcinoma in situ, and in 34 cases infiltrating carcinoma. The median time to elapse between the two operations was 20 years. The pathological diagnosis established at the first operation was most often benign duodenal ulcer. Investigation revealed in 9 cases precancerous changes and in 47 cases various grades of adenocarcinoma within the anastomosis. In 37 cases of Billroth II operations, 5 precancerous changes, 15 carcinomas in situ and 17 infiltrative cancers were located on the posterior gastric wall near the efferent small intestinal loop. In these cases there were additional changes, one precancerous, 7 carcinomas in situ and two infiltrating cancers, situated against the cephalic part of the afferent small intestinal loop. Nineteen Billroth II patients had precancers or cancers at other sites within the anastomosis or gastric remnant. The remaining 9 cases of Billroth I, gastro-enterostomy and gastric Roux-en-Y procedures are too few to allow conclusions concerning the localization of precancer or cancer in the anastomosis.

Aged↗

PubMed2006

Performance optimization of plate-mode sensors with bi-layered structure.

The acoustic characteristics of plate-mode sensors with bi-layered structures composed of a piezoelectric film and a non-piezoelectric substrate are studied by numerical calculations using the transfer matrix method. Performances of the sensors can be evaluated based on the theoretical calculations of the dispersion curves, electromechanical coupling coefficients and sensitivities of the plate-mode sensors with a bi-layered structure. In order to obtain the optimized operating conditions of the sensors, the operating mode, frequency and the ratios of thickness of piezoelectric film to that of the substrate are evaluated when the sensors are applied in gas and/or liquid conditions.

Computer Simulation↗

PubMed1976

[Early operation for the ruptured intracranial aneurysms--especially the cases operated within 48 hours after the last subarachnoid hemorrhage (author's transl)].

During the past three years from 1971 to 1973, 413 cases of cerebral aneurysms have been experienced in our clinic, in which direct intracranial operation was carried out mainly by the ligation and/or clipping of the aneurysm neck in 393 cases. Post-operative statistics showed that the cases, which were operated on within the first week after the last subarachnoid hemorrhage, had the highest mortality and morbidity rate. A closer analysis of the 64 cases with surgery within the first week revealed that the highest and second highest mortality and morbidity rates were in cases with operations on the 3rd and 4th days following the last hemorrhage, respectively. However, only one of 17 cases operated on within 48 hours died. And furthermore follow-up studies, taken 6 months to 3 years after discharge, showed that the remaining 16 cases were working and leading a useful life. In the study of 31 cases operated on within the first 4 days after the aneurysmal rupture, the most remarkeble fact is that the postoperative results were good in cases with surgery on the 1st or 2nd day, even if the pre-operative conditions were severe, such as Grade III or IV by Hunt and Hess' classification. On the contrary, in cases operated on in the 3rd or 4th-some of them Grade I or II, so-called "good risk patients"-deteriorated and cases graded III and IV all worsen or died. The important factors affecting the patient's condition after an aneurysmal rupture seem to be the degree of the increased intracranial pressure caused by the hematoma and circulatory distrubance of the cerebrospinal fluid and the degree of brain destruction caused by the intensity of the arterial blood from the rupture. Therefore it is reasonable that an early aneurysm surgery, within 48 hours, including the removal of the hematoma and the reduction of the high intracranial pressure by ventricle drainage is effective not only to prevent a possible fatal re-rupture, but also to improve the patient's poor pre-operative condition. In addition an operation within 24 hours greatly lessens the possibility of the occurrence of post-operative vasospasms by the removal of the subarchnoid clot existing around the brain artery, which may play a major role in producing vasospasms. The surgical results closely correlated with the incidence of vasospasms which were: 14.3%, 60%, 83.3% and 75% for the 1st, 2nd, 3rd and 4th days respectively. Although in cases operated on, in 3rd and 4th days continuous high intracranial pressure aggravates the conditions, the most detrimental factor affecting the poor surgical results may be attributable to cerebral infarctions due to vasospasm, especially those which appear in the post-operative stage.

Cerebral Hemorrhage↗

PubMed1982

A comparison of the effects of pimozide and nonreinforcement on discriminated operant responding in rats.

Some controversy surrounds the interpretation of the effects of dopamine receptor blocking drugs on conditioned operant responding. To assess the motoric versus the reinforcement-reducing consequences of these compounds, the effects of pimozide (1.0 mg/kg) and nonreinforcement on discriminated operant responding were compared. Rats were trained extensively on a successive discrimination implemented with the use of a multiple schedule. Rats subsequently injected with pimozide showed a significantly greater decrease in responding in the nonreinforced component than control rats showing that pimozide produces a decrease in general level of behavioral arousal. Additionally, pimozide injection resulted in an extinction-like decrease in reinforced responding over three test sessions indicating a reduction in the effects of reinforcement. However, animals treated with pimozide continued to discriminate. Transfer between pimozide and nonreinforcement was not observed probably because of the differential effects of the two procedures on behavioral arousal. Dopaminergic neurons may influence both general behavioral arousal and the effects of reinforcement but not stimulus-stimulus associative learnings.

Animals↗

PubMed1984

Social housing of rats: life-span effects on reaction time, exploration, weight, and longevity.

Sprague-Dawley rats were housed throughout their lives either in group cages or singly in standard laboratory cages. Locomotor activity was observed at selected ages and, in addition, operant conditioning procedures were used with an extensively trained subset of the animals to study reaction time and fixed ratio responding. The major effect of prolonged isolation was to induce timidity and inactivity during open field and emergence tests. Responding by isolates was depressed relative to socially-housed animals at 13 and 19 months of age although the higher levels of the social animals progressively declined during tests at 19 and 25 months. By comparison, neither housing condition nor age (7 to 25 months) systematically influenced the well-practiced operant responses (response rates, postreinforcement pauses, reaction times, foreperiod responses). A serendipitous finding was that isolated animals tended to die at earlier ages, an outcome that may be related to the fact that isolates also tended to weigh more throughout the experiment.

Age Factors↗

PubMed1978

Development of bidirectional operant modifications of the cephalic vasomotor response employing a positive reinforcer.

The purpose of the present investigation was to assess the effectiveness of a positive reinforcer in the bidirectional operant conditioning of the cephalic vasomotor response and to study the development, across sessions, of operant control over this response. To this end, 24 male, Caucasian subjects participated in five daily sessions (two shaping sessions and three operant control sessions) during which they were reinforced for producing either vasodilations (N = 12) or vasoconstrictions (N = 12) of the temporal artery. The results clearly demonstrated that the cephalic vascular responses can be brought under some degree of operant control employing a positive reinforcement paradigm and further that such control over cephalic vasoconstriction developed more rapidly than did operant control of cephalic vasodilation. Some evidence is presented to support a cognitive mediation effect.

Adolescent↗

PubMed1980

Localization of noise bands by Old World monkeys.

The acuity of auditory localization in Old World monkeys (Macaca) was determined psychophysically for 44 noise bands graded in bandwidth and center frequency. The acuity of localization was assessed through the method of constant stimuli under free-field conditions in an anechoic chamber. Monkeys were trained through positive-reinforcement operant-conditioning procedures to report a change in azimuth of the signal by releasing a response disk. The results show that localization thresholds are dependent upon the bandwidth of the signal over much of the macaque's range of audibility. Thresholds for the detection of a change in location varied from 18 degrees (for a signal 250 Hz in bandwidth centered at 11 200 Hz) to 4 degrees (for a signal 8000 Hz in bandwidth centered at 8000 Hz). The results suggest that the localization of spectrally complex signals is determined by a mechanism sensitive to periodicity (time-domain) information across the monkey's range of audibility.

Animals↗

PubMed2004

Activity of neurons in the basal magnocellular nucleus during performance of an operant task.

Spike activity was studied in 95 neurons in the basal magnocellular nucleus in rabbits during spontaneous behavior and during performance of a conditioned operant response. Nearly half the neurons (48.4%) showed significant (p < 0.05) negative correlations between spontaneous discharges and the power of the frontal lobe EEG delta rhythm; most of these cells could be identified as cholinergic projection neurons. Neurons of this group had predominantly excitatory responses to the conditioned stimulus during performance of the operant task, while the responses to the conditioned stimulus of presumptively non-cholinergic neurons, not projecting to the cortex, were mainly inhibitory. The activatory responses of neurons in the basal magnocellular nucleus to the conditioned stimulus were markedly stronger while the animals performed the operant response as compared with performances in which there was no response to the conditioned stimulus. These results provide evidence that the basal magnocellular nucleus supports the level of waking and attending required for performance of operant conditioned reflex activity.

Action Potentials↗

PubMed1988

Microcomputer-assisted filing system of cardiac catheterization records using a relational database management system.

To efficiently store and retrieve cardiac catheterization records, we have developed a computer-assisted database, which comprises a 16-bit microcomputer with dual floppy disk drives, a 20 MB random-access memory, hard disk drive, and a line printer. All programmings were accomplished using a relational database management system (R:base 5000, Microrim, Inc.). Data inquiry procedures could be performed with direct operational commands of the system as well as with preprogrammed command files, and final results of searches were printed out with a line printer. The major advantages of the present system described in this report include: (1) the relatively easy and rapid creation of the database, (2) ease of modification of the database structures even after the system design is finished, (3) operational commands in combination with conditional operator(s) are flexible and powerful enough to allow the end user to retrieve data based on various kinds of criteria, (4) a high-level programming language provided by the R:base automates a series of database procedures with relative ease, (5) relational capabilities of the database management system can enhance the possibility of reconstruction of a new data file from a single or several preexisting data files, and (6) the system can be realized at reasonable cost.

Cardiac Catheterization↗

PubMed1992

Microbial predation in a periodically operated chemostat: a global study of the interaction between natural and externally imposed frequencies.

Predator-prey systems in continuously operated chemostats exhibit sustained oscillations over a wide range of operating conditions. When the chemostat is operated periodically, the interaction of the natural oscillation frequency with the external forcing gives rise to a wealth of dynamic behavior patterns. Using numerical bifurcation techniques, we perform a detailed computational study of these patterns and the transitions (local and especially global) between them as the amplitude and frequency of the forcing vary. The transition from low-forcing-amplitude quasiperiodicity to entrainment of the chemostat behavior by strong forcing (involving the concerted closing of resonance horns) is analyzed. We concentrate on certain strong resonance phenomena between the two frequencies and provide an extensive atlas of computed phase portraits for our model system. Our observations corroborate recent mathematical results and case studies of periodically forced chemical oscillators. In particular, the existence and relative succession of several distinct types of global bifurcations resulting in chaotic transients and multistability are studied in detail. The location in the operating diagram of several key codimension 2 local bifurcations of periodic solutions is computed, and their interaction with an interesting feature we name "real-eigenvalues horns" is examined.

Animals↗

PubMed2006

Micellar enhanced ultrafiltration of eosin dye using hexadecyl pyridinium chloride.

Surfactant-based separation of toxic eosin dye is studied to estimate the potential of micellar enhanced ultrafiltration (MEUF) using cetyl(hexadecyl) pyridinium chloride (CPC) as the cationic surfactant. The optimum feed CPC concentration is found from the experimental results of pure CPC solution in a batch cell. It is in the range of 10-20 kg/m(3) to have a reasonable permeate flux and lower surfactant concentration in the permeate. Selecting 10 kg/m(3) as the feed surfactant concentration, MEUF experiments are conducted to study the retention characteristics of eosin dye in the continuous cross flow system. The effects of operating conditions, i.e., feed dye concentration, operating pressure and cross flow rate on the permeate flux and observed retention of dye are investigated.

Cetylpyridinium↗

PubMed2001

Modification of a commercial chiral stationary phase influences on enantiomer separations using simulated moving bed chromatography.

Chromatographic enantiomer separations using high-performance chromatography and the simulated moving bed (SMB) principle have become a practically useful method for obtaining optical isomers. The carbamate derivatives of amylose coated onto silica particles are very effective chiral stationary phases (CSPs). Several lots of Chiralpak AS, and its successor, Chiralpak AS-V, were compared by laser diffraction, microscopic imaging and pulse injections with increasing amounts of various racemates in order to determine the loading capacity and the competitive adsorption isotherms. Software simulations allowed to assess the possible effects due to the observed variations between the CSPs on the performance of a pilot SMB unit. The obtained results were verified by two multi-kilogram separations performed under current good manufacturing principles (cGMP) guidelines employing the two CSPs. The results of the two production runs are discussed in the light of the recently introduced "triangle theory" which allows to account for the overload conditions prevailing under preparative chromatographic conditions and to predict optimal operating conditions. Under optimized conditions the enantiomer separation of 1.4 kg racemate/kg stationary phase per day with purities >99.6% for the target enantiomer have been achieved.

Adsorption↗

PubMed1999

Development of an high-performance liquid chromatographic simulated moving bed separation from an industrial perspective.

A binary test mixture consisting of cyclopentanone and cycloheptanone is used for the performance evaluation of a pilot-scale simulated moving bed unit. The involved adsorption equilibria and the kinetic behavior are discussed in detail. The results of the test runs are evaluated using the recently introduced "triangle theory" which allows to account for the overload conditions prevailing under preparative chromatographic conditions and to select optimal operating conditions. Under optimized conditions the separation of 735 g test mixture/kg stationary phase per day with purities >99.9% for extract and raffinate stream has been achieved.

Adsorption↗

PubMed2003

Coronary calcium scoring: modelling, predicting and correcting for the effect of CT scanner spatial resolution on Agatston and volume scores.

The purpose of this study was to evaluate the impact of spatial resolution on coronary calcium scoring by x-ray CT, to assess the scoring performance of different CT scanners as they are operated in the field and to correct for the effects of CT scanner spatial resolution on coronary calcium scoring. A phantom consisting of five aluminium wires of known diameter in water was used to measure spatial resolution and to assess scoring performance. Fourteen CT scanners (three helical, two dual, two electron-beam and seven multi-detector) from four manufacturers were evaluated, some under different operating conditions. One scanner was monitored over a 3 month period and again 6 months later. Both spatial resolution and image pixel size significantly affect calcium scoring results. Spatial resolution can be measured with a precision of about 2%. Scanner spatial resolution ranged from 1 to 1.7 mm full-width-half-maximum (FWHM), and pixel size from 0.25 to 0.86 mm. Spatial resolution differences introduce systematic scoring differences that range from 38% to 1100% depending on wire size. Significant temporal variations in spatial resolution were observed in the monitored scanner. By correcting all the scanners to the same target spatial resolution, the standard deviation of individual scanners with respect to a mean value (the spread) can be reduced by 25-70% for different wires. In conclusion, scanner spatial resolution significantly affects calcium scoring and should be controlled for. Scanner performance can change over time. Under ideal conditions, CT scanners should be operated with a standard spatial resolution for calcium scoring. When this is not possible, post-processing correction is a viable alternative.

Arteriosclerosis↗

PubMed2006

On-line supervision and control of an aerobic SBR process.

This paper presents a new software developed in MATLAB for analyzing on-line data of an aerobic SBR, detecting faults and, in this case, proposing the most probable causes of fault. Process diagnosis is achieved using a statistical method divided in two main phases: off-line model building and on-line data diagnosis. The off-line model identifies the correct working conditions of the system (standard operative conditions). It includes the characterization of the deviation of the system from these standard conditions in the case of changing in the biomass properties or carbon and nitrogen load characteristics. The on-line diagnosis aims at collecting and analyzing all the available data available through industrial sensors, and at classifying the behavior of each treatment cycle. The diagnosis performance of the proposed method is tested using a data set of an aerobic SBR pilot plant.

Bacteria, Aerobic↗