Showing papers by "University of Connecticut published in 1970"

The Contact of Two Nominally Flat Rough Surfaces

Abstract: Most models of surface contact consider the surface roughness to be on one of the contacting surfaces only. The authors give a general theory of contact between two rough plane surfaces. They show that the important results of the previous models are unaffected: in particular, the load and the area of contact remain almost proportional, independently of the detailed mechanical and geometrical properties of the asperities. Further, a single-rough-surface model can always be found which will predict the same laws as a given two-rough-surface model, although the required model may be unrealistic. It does not seem possible to deduce the asperity shape or deformation mode from the load-compliance curve.

Measurement of Human Serum Ceruloplasmin by Its p-Phenylenediamine Oxidase Activity

Abstract: Optimum reaction conditions were evaluated for assay of serum ceruloplasmin by measurement of its p -phenylenediamine oxidase activity. The pH optima of p -phenylenediamine oxidase activities of human and rat ceruloplasmins were 5.45 and 5.2, respectively. The p -phenylenediamine oxidase activity of rat ceruloplasmin was markedly inhibited by phosphate (0.1 mol/liter), that of human ceruloplasmin only slightly. These reaction conditions were judged to be optimum for the ceruloplasmin assay: ( a ) substrate: p -phenylenediamine dihydrochloride, 8.9 mmol/liter; ( b ) buffer: acetate, 0.1 mol/liter; ( c ) chloride concentration: 21 mmol/liter; ( d ) serum dilution: 31-fold; ( e ) incubation: 37°C for 30 min; ( f ) spectrophotometry: 530 nm ( vs. a "serum blank" containing NaN3). Using these reaction conditions, we devised an improved technique for measuring serum ceruloplasmin. The coefficients of variation of replicate analyses by this technique were 1.25% (for "within-run" precision) and 2.8% (for "day-to-day" precision). The mean concentration of ceruloplasmin in sera from 29 healthy men was 0.315 g/liter (SD = ± 0.049, range = 0.233 to 0.402).

Passage of 14C-4-Corticosterone from the Rat Mother to the Foetus and Neonate

Abstract: SOME endocrine glands seem to influence the development and organization of neural regions which in turn control them. Thus thyroxine treatment greatly enhances the development of the median eminence in the tadpole1, and androgens organize the “male” quality of hypothalamic control of gonadotropin secretion in the mouse and rat2–4.

A picture identification test for hearing-impaired children.

Abstract: A picture identification test for measuring speech discrimination ability in hearing-impaired children was developed in two phases. In the first phase the word stimuli were evaluated to determine whether they were within the recognition vocabulary of the children and whether the pictorial representations of the words were adequate. Before the second phase, the test was revised to consist of 25 plates with 6 pictures on each plate, with only 4 of the pictures on each plate used as test stimuli. These 4 lists were given to 61 hearing-impaired children on two separate occasions. The results indicate reliability coefficients in excess of 0.87 for all four lists, with mean differences of less than 3% and correlation coefficients between lists greater than 0.84. The test appears to be a potentially valuable clinical tool in pediatric audiology. We call it the Word Intelligibility by Picture Identification test (WIPI).

Reconstruction of muscle development as a sequence of macromolecular synthesis.

Abstract: Publisher Summary This chapter hopes to promote progress toward an understanding of muscle development by attempting to integrate the results of the different lines of research An approximate schedule of the successive steps in the determination of mesodermal tissue that leads to the development of presumptive muscle cells in the limb buds of the chick is elaborated The chapter outlines the characteristics of this crucial transition period in developing muscle tissue It begins with the frustrating problem of the first appearance of cell-specific proteins Two general difficulties in the analysis of developmental processes are encountered The first of these pertains to the definition of what is meant by specific cell proteins Perhaps more critical is the second difficulty—defining what is meant by “the first appearance” of a cell-specific protein The appearance and increase in myosin in skeletal muscle is used as the standard indicator The overall activity of the transcriptional and translational system is measured as incorporation of amino acids into proteins The chapter inquires the relationship of protein accumulation to protein synthesis expressed as amino acid incorporation

Atomic Absorption Spectrometry of Nickel in Serum, Urine, and Other Biological Materials

Abstract: An atomic absorption technique is described for analysis of nickel in serum, whole blood, urine, and other biological materials. After the sample has been subjected to protein precipitation or acid digestion, nickel is extracted into methylisobutylketone as a pyrrolidine dithiocarbamate complex, and is measured by atomic absorption spectrometry. The following values (mean ±SD) were obtained for nickel in specimens from healthy subjects living in central Connecticut: serum, 0.26 ± 0.08 , µg/100 ml ( N = 40); whole blood, 0.48 ± 0.13 µg/100 ml ( N = 17); and urine, 0.23 ± 0.14 µg/100 ml, = 2.4 ± 1.1 µg/day ( N = 26). In sera obtained from 36 patients within 24 h after myocardial infarction, the mean nickel concentration was 0.51 ± 0.27 µg/100 ml (p vs. controls = 0.001). In 132 consecutive adult patients, admitted to the hospital for all diagnoses except myocardial infarction, the mean concentration of serum nickel was 0.22 ± 0.11 µg/100 ml. Measurements of serum nickel may prove to be useful in diagnosis of acute myocardial infarction.

Formation of the Initiation Complex using Muscle Messenger RNAs

Abstract: In eukaryotes, as in prokaryotes, the smaller of the two ribosomal subunits binds mRNA during the initiation of protein synthesis. The formation of the complete initiation complex, sedimenting at 75S, requires GTP, tRNA and initiation factors.

Free vs unhibited recall

Abstract: This study compared five multitrial free recalls of 20 minimally related words using two instruction conditions: Conditions, standard free recall instructions; Condition U, uninhibited recall instructions in which S s were told to emit all words occurring to them during recall. Errors were more prevalent for Condition U and were predominately item repetitions. Although level of correct recall was similar for the two conditions on the first trial, Condition U had significantly higher recall than Condition S on the last test trial. This recall superiority was attributable to less in ter trial forgetting under Condition U and was independent of the amount of error production.

Rifampicin Inhibition of Ribonucleic Acid and Protein Synthesis in Normal and Ethylenediaminetetraacetic Acid-Treated Escherichia coli

Abstract: The kinetics of ribonucleic acid (RNA) and protein synthesis in rifampicin-inhibited normal and ethylenediaminetetraacetic acid (EDTA)-treated Escherichia coli was measured. Approximately 200-fold higher external concentrations of rifampicin were needed to produce a level of inhibition in normal cells comparable to that observed in EDTA-treated cells. The rates of RNA and protein synthesis in both kinds of cells decreased exponentially, after an initial lag phase, at all rifampicin concentrations tested. The lag phase was longer and the final exponential slope less for protein synthesis than for RNA synthesis at a given rifampicin concentration. Below certain rifampicin concentrations, both the lag phase and the subsequent exponential decrease in the rates of RNA and protein synthesis were found to be rifampicin concentration dependent. At greater concentrations only the time of the lag phase was decreased by higher rifampicin concentrations, whereas the slope of the exponential decrease in the rates of RNA and protein synthesis was unaffected. In all cases, the exponential decrease continued to at least a 99.8% inhibition of the original rate of synthesis. These in vivo results are consistent with the mode of rifampicin action determined from in vitro studies; rifampicin prevents initiations of RNA polymerase on deoxyribonucleic acid, but not its propagation, by binding the enzyme essentially irreversibly. The results also indicate the size distribution of messenger RNA molecules in E. coli under our conditions.

The I‐E scale, ideological bias, and political participation1

Abstract: Summary This study was undertaken to examine ambiguities in the ability of the I-E scale to predict complex social behavior. An analysis of the items in the I-E scale suggested that the scale might contain a conservative bias Further, it was suggested that responses to the items may be determined by the individual's political and social ideology, which in turn are influenced by the political and social norms to which he has been exposed The sample consisted of one parent and a college-aged child from 60 upper-middle-class families in which the parent was visible in the community for political and social participation, half the parents interviewed were liberal, and half conservative in their political views A number of measures of political and social participation were administered, along with a shortened version of the I-E scale The findings of the study supported the contention that the “internal” items on the I-E scale are more congenial to persons holding conservative political views than for those holding liberal views. Perceived internal causality, as measured by the I-E scale, was found to be nonsignificantly correlated with any of the measures of political participation for the parent sample, with five of the six correlations being in the opposite direction from that predicted by social learning theory The results of the study were discussed in terms of White's distinction between the “moralizer” and “reformer” approach to social problems The validity of the I-E scale as a measure of a stable personality trait was called into question, as was its usefulness in predicting complex social behavior

Eradication of Rheumatic Fever An Unfulfilled Hope

Abstract: Rheumatic heart disease is considered one of the few forms of chronic heart disease which can be effectively prevented today. Yet the incidence of rheumatic fever is still appreciable and the complacency of many physicians and public health officials in regard to the rheumatic fever problem is unwarranted. It is timely, therefore, to reexamine the question of whether this disease can indeed be eradicated by presently available methods. One of the major factors limiting the prevention of initial attacks with antibiotics is that about two thirds of the patients who develop rheumaic fever do so following either asymptomatic or mild streptococcal infections. Furthermore, the low socioeconomic group, in whom the risk of rheumatic fever is the greatest, is the least likely to receive adequate care even for overt respiratory infections. Although the number of recurrent attacks has been reduced, approximately 10% of rheumatic patients still develop recurrences either because they are not on prophylaxis at all or ...

The sociology of mate swapping: Or the family that swings together clings together∗

Abstract: In the early decades of this century, and to a certain extent still today, social scientists equated deviant behavior with disease and set about to find the cures. The tone of this early perspective is nicely illustrated by the following excerpt: The study of social pathology is undertaken not to breed pessimism but to furnish a rational ground for faith in the future of the world. The diseases of society, like the diseases of the human body, are to be studied so that remedies may be found for them where they exist, but most of all, that by a larger wisdom the number of diseases may be reduced to the lowest terms and we may set ourselves to social tasks with the ideal of conquering them altogether (Smith, 1911).

Proactive Interference in Short-Term Memory as a Function of Prior-Item Retention Interval:

Abstract: The experiment was conducted to examine the effect of prior-item retention interval on the retention of a given item in a short-term memory test series. There were five conditions. The retention in...

Maintaining social acceptance gains made by mentally retarded children.

Abstract: This study is an extension of one conducted by Chennault (1967) in which the social acceptability of unpopular students in EMR special classes was increased by pairing them with popular students for the planning and presentation of a skit. The present investigators were concerned about the permanence of such gains. The purpose of the present research was an attempt to produce similar pre to posttest gains and then one month later administer a post-posttest to determine whether these gains were maintained. The following was hypothesized: the pre to posttest sociometric gains made by the experimental students will be greater than those for the control students, but the pre to post-posttest gains of the two groups will not differ. A modified Ohio Social Acceptance Scale (OSAS) was employed as the pretest, posttest, and post-posrtesr measure. The OSAS consists of six descriptive paragraphs ranging from high acceptance to active rejection. Two of these paragraphs were eliminated and the four remaining paragraphs were assigned weights of three, two, one, and zero to correspond to the instrument employed by Chennault (1967). The OSAS was administered to 95 students in four intermediate and two junior high educable special classes. On the basis of the pretest, the four least accepted and the two most accepted students in each class were determined. The mean IQ and CA for the 24 least accepted students was 65 (WISC) and 11-7 respectively. In each class the two least accepted Students were randomly assigned to experimental (E) and control (C) conditions, and this procedure was repeated for the next two least accepted students, The two E students and the two most accepted students of each class par-

Effect of carbon dioxide, osmotic potential of nutrient solution, and light intensity on transpiration and resistance to flow of water in pepper plants.

Abstract: The rate of transpiration, temperature of the leaves, and relative water content of leaves of pepper plants were measured in a small chamber in which the temperature, relative humidity, and carbon dioxide concentration of recirculated air were controlled and measured. The data reported were obtained by noting the response of pepper plants to all combinations of the following treatments: high light, 1.5 x 10(6) ergs per square centimeter per second; low light, 3.0 x 10(4) ergs per square centimeter per second; three levels of CO(2): 50, 268, and 730 parts per million; nutrient solution osmotic potentials of -0.5, -5.0, -7.5, and -9.5 bars.The rate of transpiration of pepper plants was reduced by a decrease in osmotic potential of the nutrient solution, an increase in CO(2) concentration in the ambient air, and a decrease in light intensity. The response, as measured by transpiration, to the three variables, light, CO(2), and osmotic potential indicated that each variable influenced a different and independent mechanism. A change in a single variable produced essentially the same percentage change at all levels of the other variables. The rate of movement of water from roots to leaves was in response to water potential gradient and not the actual potential in the leaves.The resistance to flow of water through the plants (R) was estimated by dividing the difference between the water potentials of the solution and the leaves by the rate of transpiration. The data indicated an increase in R as the rate of transpiration decreased. The type and size of errors encountered in the estimation of R and location of R within the plant are discussed.

Maternal behavior: differences between mother and virgin mice as a function of the testing procedure.

Abstract: Retrieval by lactating and virgin mice was compared in a straight alley and a T-maze. In both test situations the retrieval performance of the lactating mouse was superior to that of the virgin animal. No discrimination was seen between a live pup and a dead pup; a rubber toy, however, was retrieved least by both the lactating and virgin mice. Contrary to previous results, these experiments demonstrate a significant difference in maternal behavior between lactating and virgin mice.

Retrieval from iconic memory with shape as the selection criterion

Abstract: Selection of items from iconic memory on the basis of shape was studied by means of the Sperling (1960) partial report procedure. The results indicated that partial report by shape was superior to whole report, that partial report by location was superior to partial report by shape, and that the accuracy of report as a function of delay of indicator declined at the same rate for selection by shape and selection by location. The results were discussed in the framework of the flow of visual information within S.