Degree Of Individual Variation Research Articles

Social organization ofPlatythyrea lamellosa(Roger) (Hymenoptera: Formicidae): II. Division of labour

Although colonies of Platythyrea lamellosa were found to be consistently queenless, the division of labour amongst workers resembled the pattern generally characteristic of ants. Mated workers were involved only with reproduction and tending larvae. The behaviour of virgin workers was influenced by their age. Athough they showed a degree of individual variation in behaviour, they were clearly organized into three roles: nursing eggs and larvae; tending cocoons and domestic tasks; and foraging. Behaviours sharing a common focus (e.g. larvae or prey) were highly associated. The integration of individual variability into a relatively precise pattern at the level of the colony was not merely a statistical artifact, but probably involved the way that tasks were spatially localized within the nest, as well as the changing physiological state of individual ants. Nest structure is probably important in this regard.

Individual variation in winter foraging of black-capped chickadees

Wintering black-capped chickadees (Paridae: Parus atricapillus) in northwestern Massachusetts showed a high degree of individual variation in foraging behavior. After accounting for the effects of different habitats and weather conditions, individual differences comprised 6–17% of the total observed variation in four measures of foraging location and rate of feeding. Differences between age and sex groups were not significant and explained comparatively little variation (0.0–1.4%). The chickadees did not fall into a few distinct behavioral categories but instead showed continuous variation on all measures of foraging behavior. It appeared that some variation among individuals was a consequence of behavioral convergence within social groups, since birds that were observed together were more similar in their foraging than expected by chance, after taking habitat differences into account. Our results therefore do not support the interpretation that individual variation in feeding behavior serves to reduce exploitation competition within social groups.

Neurohumoral control of ionic pumping in molluscan muscle—II. evidence for an electrogenic sodium pump in radular protractor muscle of Busycon canaliculatum

Abstract 1. A sucrose gap technique was used to study the effects of brief periods of superfusion with solutions in which the potassium content of artificial sea water was reduced or omitted. 2. Stepwise reduction in bath potassium had a complex effect, culminating in the response to potassium-free solution. This was composed of a rapid initial hyperpolarizing phase, overtaken by a slower depolarizing phase, which was accompanied by force. 3. Readmission of bath potassium induced a transient after-hyperpolarization. 4. There was a high degree of individual variability in RPM preparations from different animals. This was particularly evident in cases in which either the hyperpolarizing phase or the depolarizing phase predominated, in the response to zero-potassium, but the muscles from any one animal showed reproducible responses. 5. The RPM behaved as predicted on Nernst equation grounds, to the extent that initial hyperpolarization showed stepwise increases with stepwise reduction in [K + ] 0 , but as the steps approached zero-potassium there was a stepwise increase in the slower depolarizing response, suggesting reduction in electrogenic Na-K exchange. 6. In Na-free solution the depolarizing phase of the response to zero-K was abolished, leaving only an enhanced hyperpolarizing phase. 7. Abrupt chilling had a depolarizing effect. 8. There was only a slight increase in resistance during the action of zero K.

How to get well in tzintzuntzan

Latin American humoral pathology, the so-called ‘hot—cold syndrome’ has been extensively described during the past 50 years. Most attention has been directed to the characteristics of the ‘hot—cold’ classification, the basis for ascription of humoral quality, the degree of individual variation in assigning qualities and above all, to etiology. Almost no systematic attention has been given to humoral therapies. This paper describes and classifies the wide variety of therapies characterizing the traditional humoral medicine of Tzintzuntzan, Michoacán, Mexico. The names of these therapies, and those of the illnesses for which they are prescribed, point directly to Spanish and Mexican medical texts and home-care recetarios of the colonial period, publications reflecting classical Graeco-Roman medicine. The presence of significant numbers of Spaniards and Spanish-speaking residents in Tzintzuntzan for three centuries following the Conquest provides an explanation as to how classical humoral pathology could become rooted in a Mexican village.

Heterogeneity of Es-1 esterases in the rabbit (Oryctolagus cuniculus).

Analysis of the Es-1 system in the rabbit with polyacrylamide gel electrophoresis (PAGE) revealed a high degree of individual variation. In the liver the number of esterase bands found in the Es-1 region of the gels ranged from 2 to 16. The results indicate that one locus with three alleles is responsible for all of the esterase bands in the Es-1 region. The most plausible explanation for the observed heterogeneity is that each of the alleles codes for a protein (MW 65,000 +/- 2000) that is changed by posttranslational modifications, thus giving rise to two to five monomeric enzymes with esterase activity. Polymerization of these monomers then results in 1-11 dimers. Based on similarities with mouse Es-9, chromosomal homology between rabbit Es-1 and mouse Es-9 is proposed.

Local immunity and Ostertagia circumcingta: Changes in the gastric lymph of sheep after a primary infection

Some aspects of the kinetics of the primary local immune response to O. circumcincta were studied by monitoring the flow and composition of gastric lymph from 4 sheep for 3 weeks after infection with 50 000 larvae. A significant increase in the frequency of lymphoblasts in the lymph showed that all the sheep were responding immunologically to the parasites from day 8 onwards. However, considerable individual variation in degree and timing was evident in other aspects of the immune response; 2 animals responded with large increases in lymphocyte output which reached a peak on day 5 or day 10, whereas the main response in the other 2 sheep appeared to be inflammatory in nature, with large increases in lymph flow and eosinophil output which occurred during the third week of infection. No significant changes in the content of IgA or IgA anti-worm antibody were detected in the lymph, but pepsinogen concentrations were significantly raised from day 12 onwards.

The pattern of interhemispheric connections and its relationship to extrastriate visual areas in the macaque monkey

The distribution of interhemispheric connections was studied in extrastriate visual cortex of the macaque monkey. Callosal fiber terminations were identified by staining for anterograde degeneration following transection of the splenium of the corpus callosum. Retrogradely labeled cell bodies of callosal projection neurons were identified histochemically following application of horseradish peroxidase to the cut surface of the callosum. Results were displayed on unfolded, two-dimensional representations of the cortex, which permitted spatial and topological relationships between callosal recipient and callosal free cortical regions to be discerned readily. The overall pattern of callosal inputs to visual cortex can be subdivided into nine callosal recipient zones which surround seven callosal free regions in the occipital, temporal, and parietal lobes. This pattern provides reliable and useful landmarks for identifying the borders of at least five topographically organized extrastriate visual areas. There is a pronounced dorsoventral asymmetry in callosal projections, not recognized in previous studies, which reflects an asymmetry in the organization of visual areas in dorsal versus ventral halves of the occipital lobe. The pattern of callosal fiber terminations is mirrored by a very similar distribution of callosal projection neurons. There are significant regional differences in the laminar distribution of callosal projection cells, and these differences may reflect functionally distinct cortical subdivisions. A considerable degree of individual variability was found in the relationship of callosal connections to gyral and sulcal landmarks as well as in the fine structure of individual callosal recipient strips, suggesting that each animal has a unique "callosal fingerprint." These findings emphasize the usefulness of the callosal pathway in elucidating the functional organization of extrastriate visual cortex.

Epidural Morphine Following Epidural Local Anesthesia

The authors measured the minute inspired ventilation (VI) and airway occlusion pressure (P 100) responses to CO2 during rebreathing in ten patients who were given epidural morphine for analgesia following lower extremity or lower abdominal surgery. All patients were studied and blood samples for morphine analysis were obtained at four different times: preoperatively, postoperatively premorphine, and one and six hours after a single 10-mg epidural dose of preservative-free morphine in 10 ml of saline. All patients reported effective analgesia with a duration ranging from 8-25.5 h. There were no differences between the pre- and postoperative VI vs. PCO2 and P100 vs. PCO2 response slopes, indicating that the epidural local anesthetic alone had no effect on respiratory drive. Administration of 10 mg morphine epidurally caused a significant 22 per cent decrease in the average VI vs. PCO2 slope and a 33 per cent decrease in the average P100 vs. PCO2 slope one hour postmorphine when compared to the postoperative slopes. The average decrease in VI vs. PCO2 at 6 h postmorphine was not significant. The average P100 vs. PCO2 response slope was decreased significantly at 6 h postmorphine by 27 per cent. There was no significant correlation between serum morphine concentration and the ventilatory responses. The authors conclude that morphine administered by the epidural route produces decreased respiratory drive and that there is a high degree of individual variability in the magnitude and time course of this effect.

Road assignment—I: Principles and parameters of model formulation

The factors which influence the formulation of road assignment models and the criteria by which different techniques may be compared and evaluated are discussed. In order to give the discussion a quantitative basis three basic parameters of network and model characteristics are defined: the degree of mathematical convergence achieved by the model (δ), the degree of individual variations in the perception of travel costs (ϵ 1), and the relative change in average travel costs due to congestion (ϵ 2). A number of general principles involving these parameters are proposed. The importance of intrinsic errors and of overall objectives in formulating an assignment model are also strongly stressed. Parts II and III of this paper (the following two articles) illustrate the application of these principles in more specific situations: the GLTS model where capacity restraint is a dominant factor, and the development of stochastic methods for situations where capacity effects are generally excluded.

The etiology of trigeminal neuralgia.

The etiology in the great majority of cases of tic douloureux remains as much of a mystery today 1 as in the day of Fothergill. 2 In the present study a structural variation of the base of the skull is reported which is compatible with the clinical symptomatology and the natural history of this disease and may explain why no specific lesions have been found. The Structural Variant For reasons to be discussed subsequently, it seems reasonable to believe that the causal factor in trigeminal neuralgia may be a structural abnormality, related probably toaging and other factors. The possibility that the relationship of the gasserian (semilunar) ganglion to the internal carotid artery might provide an explanation for trigeminal neuralgia occurred to the writer when studying the relations of the ganglion at the base of the skull and noting the considerable degree of individual variation. To try to determine whether this

Rated association values of numbers from 0–100

Summary Ratings of the association values on a five-point scale by 95 S s are reported for the 101 numbers between 0 and 100. The results reveal sizable and relatively consistent differences between numbers which are shown to be related to learning difficulty, as well as a high degree of individual variability.

カツオブシの品質-V

Experiments were carried out twice already with the finding that factors deciding the quality of Katsuwo-bushi are not histidine inosinate-like substances, but rather seem to be fat-content. However it is obscure whether the relations exist beyond the degree of individual variation or not. Therefore, quantitative determinations were made of moisture, fat, amino nitrogen, histidine, adenylic acid and inosinic acid using six pieces each of best and lowest quality of Katsuwo-bushi. Analyzing with significance test of two means of each determined values, the writers found only fat and inosinic acid contents to be significant, i.e., in the best quality a smaller amount of fat and larger amount of inosinic acid are contained obviously than in the lowest quality. Inosinic acid, in some instances, can be the factor deciding the quality as well as fat content.

Biological Studies with Arsenic76 II. Excretion and Tissue Localization

Summary1. Arsenic excretion was studied in man, rats, and rabbits. Less than 10% of the excreted arsenic is found in feces in any of these species; rats have by far the slowest rate of excretion.2. Data are given for arsenic distribution in various organs in man, the rat, the rabbit, and 2 strains of mouse.3. The degree of individual variation within each species was very great; in contrast to man and to other animals studied, the rat retains most of the injected dose in the blood for a considerable length of time.4. The ratio of arsenic concentration in kidney, liver, and spleen of healthy inbred mice was found to be fairly constant for a given time after administration, and this ratio is suggested as a criterion for effects of various types of treatment.5. Using this ratio as criterion, it was found that arsenic distribution is altered by the presence of transplanted tumors.6. Factors changing arsenic distribution are discussed in relation to effects on levels of sulfhydryl-containing substances.

SENSITIVITY TO WAR GASES

To the Editor:— I read with keen interest a communication toThe Journal, Nov. 29, 1941, page 1879, by Frank B. Queen, M.D., Major, M. C., U. S. Army, and Tom Stander, M.D., Major, M. C., U. S. Army, in which they report a case of severe generalized hypersensitivity to tear gas (CN) considered to be idiopathic. Of particular interest in the case is the fact that once before the patient had, on transient exposure by passing through a cloud of tear gas during a course of instruction while in the National Guard, experienced itching of the skin which, though remembered seventeen years after the event, was not incapacitating. Here at Edgewood Arsenal, the center of the Chemical Warfare Service, we have observed that all persons are sensitive to chemical agents when exposed to their effect for the first time. A certain degree of individual variation in sensitivity does occur

THE PERIOD OF INFECTIVITY OF THE BLOOD IN MEASLES

In our supplemental note 1 we published in some detail the experiments of which our first note 2 was a brief summary. It will be recalled that up to that time we had inoculated nine rhesus monkeys with blood from four human Patients with measles, and that of these animals only four (Nos. 38, 12, 6 and 8) had given any very significant evidence of a reaction, and that only two of these (Nos. 6 and 8) were clearly marked. In other words, of nine animals inoculated only two gave unmistakable reactions, two others gave reactions that we regarded as significant, while in the remaining five a reaction was either not appreciable or at most only suggestive. This result we were at first disposed to regard as due to a low degree of susceptibility in the monkey, combined with a a considerable degree of individual variation. In spite of this