Showing papers by "Williams College published in 1970"
TL;DR: Appreciable amounts of suspended matter in surface waters are restricted to within a few kilometers of the Atlantic coast, and particles that escape estuaries or are discharged by rivers into the shelf region tend to travel longshoreward rather than seaward.
Abstract: Appreciable Amounts Of suspended matter (> 1.0 milligram per liter) in surface waters are restricted to within a few kilometers of the Atlantic coast. Particles that escape estuaries or are discharged by rivers into the shelf region tend to travel longshoreward rather than seaward. Suspended matter farther offshore, chiefly amorphous organic particles, totals 0.1 milligram per liter or less. Soot, fly ash, processed cellulose, and other pollutants are widespread.
100 citations
TL;DR: Three experiments were conducted to test the hypothesis that (a) the stimulus inducing the luteal response in female mice results from swelling of the male's penis during the ejaculatory reflex, and (b) the subsequent presence of the copulatory plug in the vagina is unnecessary for the induction of lutenal activity.
38 citations
TL;DR: The probability of recognizing tachistoscopically presented typed and handwritten words was found when the two types of materials were presented in separate lists, and when presented together in a mixed list.
Abstract: Three experiments of identical design, but using different basic materials are reported. In experiment I the probability of recognizing tachistoscopically presented typed and handwritten words was ...
31 citations
TL;DR: The interpretation in terms of self-regulation of motivation seems to apply to dorsal pricking behaviour in the courtship of the male three-spined stickleback (Gasterosteus aculeatus L.).
Abstract: TINBERGEN1 has argued that the functions of courtship behaviour in animal species are (a) the orientation of the sexes, (b) the synchronization of mating, (c) the prevention of interbreeding between species and (d) the suppression of non-sexual responses in the partner. More recently, Chance2 has proposed that, in addition, certain courtship acts, which he calls “cut-off” behaviour, might function to adjust the motivation of the performer of the display. Such activities, Chance suggests, serve to make behaviour more flexible by temporarily “cutting off” a stimulus “producing cumulative mood effects” or to facilitate a change from one type of motivation to a more appropriate one. The interpretation in terms of self-regulation of motivation seems to apply to dorsal pricking behaviour in the courtship of the male three-spined stickleback (Gasterosteus aculeatus L.).
20 citations
TL;DR: Male mice were given either testosterone, estrogen, or oil within 2–20 hr of birth, and the development of sexual responses, and certain aspects of adult sexual behavior, were observed.
19 citations
TL;DR: Hemoglobins extracted from larval, eft and adult stages of Triturus viridescens were characterized on polyacrylamide gels showed Qualitative changes in hemoglobin occur during the initial but not the second metamorphosis.
15 citations
12 citations
12 citations
TL;DR: The history of political exiles concerns the collective habits of those Europeans who fled persecution or upheaval at home to seek not only personal refuge or religious freedom but also political recovery abroad as mentioned in this paper.
Abstract: Historians generally dislike lost causes. They seek to explain what happened, rather than what might have been, and have consequently neglected the story of political emigrations. Granted, the study of emigres is full of methodological pitfalls for the unwary: biased accounts of past issues, outright forgeries of documentary evidence, personal recriminations that serve to distort political reality, and a pervasive mood of bitterness, acrimony, nostalgia, and endless hope. Yet it is an important story, not only because of its intrinsic merit as a political phenomenon worth studying, but also because of the effect that exiles have had both in their place of refuge and in their homeland when they have been able to return. He who would ignore the emigres might do well to recall that the experience of exile helped fashion the political careers of Marx, Lenin, and Trotsky, as well as of Charles II and Louis XVIII.1 In European history the emergence of political exiles is a relatively recent phenomenon, coinciding with the rise of nation-states out of the religious wars of the sixteenth and seventeenth centuries and the era of revolutions which followed. Only with the secular loyalties of citizenship could there be the secular disloyalties of exile, forced or voluntary. The history of political exiles concerns the collective habits of those Europeans who fled persecution or upheaval at home to seek not only personal refuge or religious freedom but also political recovery abroad. It is the political behavior of such sojourners which has not attracted the attention of historians, who have concerned themselves with many related movements of migration: economic shifts inside Europe and across the sea, the flight of persecuted religious or national minorities, literary exiles, and wartime refugee movements.
12 citations
TL;DR: McMahon and DeWitt as discussed by the authors showed that the appearance of mature tadpole hemoglobin is associated with changes in ribosomal RNA synthesis in the adult bullfrog, which is characteristic of the adult frog hemoglobin.
Abstract: catesbeiana tadpoles, hemoglobin synthesis in the circulating red blood cells initially declines to very low levels . This period is followed by the synthesis of a new hemoglobin which is characteristic of the adult bullfrog. Radioautographic studies on smears of whole blood cells have indicated that the production of adult hemoglobin is associated with the appearance of a new cell type which differs from mature tadpole blood cells in size and shape (Moss and Ingram, 1965 ; 1968 a and b ; DeWitt, 1968) . Recently it has been shown that the thyroxin-induced switch in hemoglobin synthesis is also accompanied by striking changes in the synthesis of erythrocyte ribosomal RNA . These include an initial breakdown of ribosomal RNA followed by an increase in RNA synthesis at the time of appearance of frog hemoglobin (McMahon and DeWitt, 1968) . It was expected that biochemical changes occurring during the switch in hemoglobin synthesis could be correlated with changes in cell morphology. Ultrastructural studies were, therefore, initiated to examine the cell types present in the peripheral blood following the administration of thyroxin to bullfrog tadpoles . These results clearly demonstrate the existence of two distinct red blood cell types which appear to differ significantly in their synthetic activities .
11 citations
01 Jan 1970
TL;DR: In this article, it is argued that the conventional wisdom which accords priority to investment at the primary level of education in developing countries may be based on methodologically flawed estimates and that the problem arises on account of the filtering down of educated entrants to the labour market into lesser jobs as education is expanded.
Abstract: It is argued that the conventional wisdom which accords priority to investment at the primary level of education in developing countries may be based on methodologically flawed estimates. The problem arises on account of the ‘filtering down’ of educated entrants to the labour market into lesser jobs as education is expanded. The (conventionally measured) average rate of return is compared with estimates of the marginal rate of return to the entering cohort. An illustration for Kenya shows that the rate of return on primary schooling is highly sensitive to this distinction, whereas that on secondary schooling is not: the hierarchy of returns is reversed. Contrary to the conventional wisdom, the jury is still out.
TL;DR: In this paper, the authors were asked to listen to a list of words and to identify repeated words upon hearing them, interspersed with the repetitions were words that were associatively or acoustically related to the repeated words.
Abstract: Ss were asked to listen to a list of words and to identify repeated words upon hearing them. Interspersed with the repetitions were words that were associatively or acoustically related to the repeated words. The intrusion errors were analyzed and the differences across word class found to be highly significant; application of signal-detection theory provided a means of quantifying this difference.
01 Jan 1970
TL;DR: Time-trend analysis is a mathematical technique used to smooth out irregularities in geologic data based on a sequence of observations taken along a traverse or on a vertical measured section as mentioned in this paper.
Abstract: Time-trend analysis is a mathematical technique used to smooth out irregularities in geologic data based on a sequence of observations taken along a traverse or on a vertical measured section. A highspeed digital computer is used to calculate smoothed values and plot the time-trend curves, which in turn are used to study the underlying trends of sedimentation. Nine smoothing equations containing from 5 to 21 terms are available to compute curves with varying degrees of smoothing. The smoothing sum of squares is a measure of the total variability accounted for by each of the smoothing equations and can be used to detect a rhythm or cycle in the data. Several closely spaced, measured sections are being investigated in the Upper Ordovician of southeastern Indiana to reconstruct the sequence of environments which existed during their deposition. Time-trend curves are being used to study the relationship between physical properties of the environment and faunal distribution. The percentage of limestone in a sequence of thin limestone and shale layers is used as an index of environmental conditions. The corresponding time-trend curves are plotted for ten genera of brachiopods to examine their vertical distribution. There appears to be a definite relationship between the amount of limestone in the section and the occurrence of certain brachiopod genera. The maximum on the limestone percentage curve corresponds closely to the disappearance of one brachiopod genus and the introduction of two new genera, indicating a significant shift in environmental conditions.