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Biomedical subjects

G Inbar

Publications and source records attributed to G Inbar.

10 recordsLinked to original sources

Examination of the gamma equilibrium point hypothesis when applied to single degree of freedom movements performed with different inertial loads.

One of the theories of human motor control is the gamma Equilibrium Point Hypothesis. It is an attractive theory since it offers an easy control scheme where the planned trajectory shifts monotionically from an initial to a final equilibrium state. The feasibility of this model was tested by reconstructing the virtual trajectory and the stiffness profiles for movements performed with different inertial loads and examining them. Three types of movements were tested: passive movements, targeted movements, and repetitive movements. Each of the movements was performed with five different inertial loads. Plausible virtual trajectories and stiffness profiles were reconstructed based on the gamma Equilibrium Point Hypothesis for the three different types of movements performed with different inertial loads. However, the simple control strategy supported by the model, where the planned trajectory shifts monotonically from an initial to a final equilibrium state, could not be supported for targeted movements performed with added inertial load. To test the feasibility of the model further we must examine the probability that the human motor control system would choose a trajectory more complicated than the actual trajectory to control.

Adult↗

The influence of the fullness of milk in the breasts on the concentration of lactic acid in postexercise breast milk.

The purpose of this study was to observe the influence of the fullness of breast milk in the breasts prior to exercise on the concentration of lactic acid in breast milk following exercise. Twenty-three lactating women were randomly assigned to Group E (n = 11), which nursed and/or collected as much of the breast milk as possible prior to maximal exercise, and Group F (n = 12), which did not nurse or collect milk at least two hours prior to maximal exercise. Milk was collected at rest preexercise and 10, 30, 60 and 90 minutes postexercise and was analyzed for concentrations of lactic acid. ANOVA demonstrated 1) a significant increase in lactic acid in the milk at all postexercise collections for both groups and 2) a significant group vs postexercise time interaction for lactic acid concentration in milk. These differences represented differences in 1) time to peak lactic acid concentrations in milk (Group F = 10 min; Group E = 30 min) and 2) time for postexercise decreases in lactic acid concentrations in milk. Thus, the state of fullness of milk in the breasts is a factor which affects the concentration of lactic acid in breast milk following maximal exercise.

Adult↗

Infant acceptance of postexercise breast milk.

The purpose of this study was to observe the infant acceptance of postexercise breast milk. Twenty-six lactating postpartum women exercised to maximum (maximum oxygen consumption = 35.1 +/- 9.2 [SD] mL min-1 kg-1) on a treadmill. Breast milk was collected via self-expression at rest before exercise and at 10 and 30 minutes postexercise and analyzed for lactic acid by enzymatic methods. Following exercise, infants were presented with their mothers' pre-exercise and postexercise milk in a double-blind design. The mother rated the infant's acceptance of the milk samples. There was a significant difference in acceptance of pre-exercise and postexercise milk as analyzed by analysis of variance. Maximal exercise resulted in a significant increase in lactic acid concentration in breast milk that may be high enough to affect the taste of the milk. The decreased acceptance of postexercise milk was associated with increased lactic acid concentration. Suggestions to circumvent the decreased acceptance are offered.

Adult↗

Exercise-responsive cardiac pacemakers: review and performance evaluation.

The various aspects of the state of the art of exercise, or physiological responsive pacemakers (PM) are discussed. Models are used to assess the performance of PM controllers already on the market or in experimental stages. Emphasis is placed on comparison between open-loop and closed-loop controllers in light of the anticipation that future PM will have more sophisticated multiparameter expert system controllers.

Animals↗

Ordinal discrimination of ECG orthogonal features.

A rigorous mathematical analysis of Electrocardiogram (ECG) data is presented in this paper, as a decision support system for ECG interpretation. The mathematical analysis: provides a new insight to the ECG data, provides flexibility for future understanding of the heart system or the ECG, and avoids the need of measurements of parameters and the disagreement concerning the standard criteria of those parameters. The system enables compressed storage of the ECG data and an easy and accurate retrieval ability. An "ordinal straight line" method is presented for simple description of the ECG features as a combination of straight lines. A new developed discrimination method--the bisector method--is used for discrimination and classification between the normal and pathological groups. The physician's decision is based on both the physician's heuristic approach and the system's classification.

Data Collection↗

An 'outbreak' of pulmonary pseudoinfection by Serratia marcescens.

The recovery of multiple isolates of Serratia marcescens from bronchial lavage specimens was traced to contaminated fibreoptic bronchoscopes. Four patients were involved and none became infected. Awareness of a cluster of serratia cultures and immediate investigation and institution of control measures may have prevented the occurrence of true infections.

Aged↗

The influence of the gamma system on cross-correlated activity of Ia muscle spindles and its relation to information transmission.

In the decerebrate cat during static or slowly varying (less than 0.3 Hz) muscle stretches, the activity of muscle spindle (MS) pairs was poorly correlated and such correlation was not changed after ventral root sectioning. With slightly faster sinusoidal stretches (0.3-20 Hz) activity in pairs of MS was also poorly correlated. However, sectioning of the ventral roots produced preferential firing frequencies in the same muscle spindle pairs and increased their degree of correlation. The increase in correlation between MS activity detected after suppressing the gamma bias appeared to arise from extrinsic 60 Hz power line vibration in the range of micrometers. Nevertheless, activation of the gamma system could suppress such phase locking. When frequencies above 20 Hz were used, the gamma system could not decorrelate the MS pair activity since the two units became locked to their common input signal. It is suggested that decorrelation of MS activity by gamma influence may improve the fidelity of the information transmitted by the Ia MS ensemble by filtering distortion harmonics, as well as damping tremor oscillations in the stretch reflex loop.

Animals↗

Israeli psychological casualties of the Persian Gulf war: characteristics, therapy, and selected issues.

The Persian Gulf war in 1991 presented Israel with its first experience of a threat of chemical attack on the home front. Ground-to-ground missiles were aimed directly at civilian populations, threatening death and destruction over a period of several weeks. Uncertainty as to time, place, and nature of the missile attacks affected the civilian population psychologically. The psychological responses of the population were the result of the continuous nature of the emergency which affected the entire population, and the destruction, injury, and displacement which affected those who were the targets of the attacks. The primary psychological effects of the emergency were investigated in several ways: surveys of samples of civilian and rear-echelon military populations, studies of the military personnel who asked for ambulatory psychological treatment as a result of the war, and studies of the specific populations that bore the brunt of the actual physical attacks were conducted. These studies show a high level of distress in the samples, with considerable differentiation between the populations. Levels of functioning generally remained intact even among the displaced or injured. Interventions were based on experience gained in the treatment of combat stress reaction. The issues of evacuation of psychological casualties to hospitals, psychiatric aspects of chemical attacks, and secondary traumatization of therapeutic and other staff are emphasized.

Chemical Warfare↗