Showing papers by "Williams College published in 1987"

Adult recruitment in chorus frogs: effects of size and date at metamorphosis'

Abstract: A cohort of tadpoles of the chorus frog, Pseudacris triseriata, on Isle Royale, Michigan, was marked to determine the effect of body size and date at metamorphosis on survivorship to maturity. The cohort was classified at metamorphosis into four categories based on size and date of metamorphosis: large-early, small-early, large-late, and small- late. The number of frogs in each category that returned to breed on the study area was monitored for the following 2 yr. Long larval period and small body size at metamorphosis influenced recruitment to the breeding population by delaying maturity. Frogs that meta- morphosed at large size maintained their size advantage at maturity. Large body size and early date at metamorphosis increased survivorship to maturity by enhancing the chance that reproductive size was attained within 1 yr of metamorphosis. Frogs that were recap- tured in the 2nd yr after metamorphosis, when all frogs had attained mature size, were from all four categories in the same proportions marked at metamorphosis, indicating that unless breeding during the Ist yr led to higher mortality of large individuals, survival rate after metamorphosis was not related to size or date at metamorphosis.

Unconscious Influences of Memory for a Prior Event

Abstract: We interpret the difference between aware and unaware forms of memory in terms of Polanyi's distinction between tool and object. Aware memory, such as recognition and recall, occurs when memory serves as an object of attention. Unaware memory occurs when memory serves as a tool to accomplish a present task. Both memory-as-tool and memory-as-object can rely on memory for specific prior experiences. Memory used as a tool is a pervasive form of unconscious influence. We present experiments in which memory used as a tool enhances perception, lowers the subjective experience of background noise, increases the fame of nonfamous names, and lowers estimates of the difficulty of anagrams. To escape the pervasive effects of unconscious memory, one must consciously remember the past experience, understand its influence in the present task, and possess a good theory to serve as an alternative basis for behavior. These three criteria may seldom be met.

Structural conventions for group I introns

Abstract: Conventions for nomenclature of structural elements and a standard secondary structure representation for group I introns have been established by workers in the field. These conventions are designed to facilitate effective communication of information concerning the structure and function of these self-splicing introns.

The Development of Defense Mechanisms

Abstract: It is proposed that defense mechanisms may be characterized as forming a hierarchy, from least to most complex, and that the lowest level defenses emerge early in life, while the more complex defenses emerge later in development Three defenses–Denial, Projection and Identification–were chosen to test this assumption A method for assessing the use of these defenses in Thematic Apperception Test (TAT) stories was developed and validated in a study of four age groups preschool, elementary school, early adolescent, and late adolescent The results of the study were consistent with the prediction Denial was used most frequently by preschool children, and decreased in use thereafter Identification was used minimally by preschool children but increased steadily through adolescence The use of Projection was most frequent in the two middle age groups Some evidence for sex differences, based on the internal/external orientation of the defense, also was found

Coercive sexual fantasies of college men as predictors of self‐reported likelihood to rape and overt sexual aggression

Abstract: In this study we explored the role of coercive sexual fantasies among men as predictors of hypothetical willingness to rape and self‐reports of past sexual aggression. Men (N = 114) enrolled in undergraduate psychology courses were given questionnaires assessing sexual fantasies, acceptance of rape myths, and aggressive tendencies as well as measures of likelihood to commit rape and past history of coercive sexual behavior. Likelihood to rape was found to be correlated with reports of coercive sexual fantasies (r = .51, p < .001), rape myth acceptance (r = .21, p < .05), and aggressive tendencies (r = .21, p < .05), yielding a multiple R of .44 (p < .001). Past coercive sexual behavior was correlated with coercive sexual fantasies (r = .26, p < .05), aggressive tendencies (r = .22, p < .05), and with their interaction (r = .39, p < .01), yielding a multiple R of .41 (p < .05). The two target variables, likelihood to rape and coercive sexual behavior, were not significantly associated with one another. The...

Effects of mood on self-appraisal of health status.

Abstract: Two experiments investigated the effects of temporary mood on the self-perception of health status. In Experiment 1, participants viewed one of two videotapes designed to induce either positive or negative mood. Under the guise of a second experiment, they were asked to imagine an illness-related scenario and to provide judgments concerning their health status. As predicted, positive-induction participants judged their health more favorably than negative-induction participants. Experiment 2 examined the mediating role of illness-relevant thinking in this mood effect. After seeing one of the two mood-induction tapes, some participants were asked to imagine either an illness-related or illness-unrelated scenario. A third group was given no instructions concerning imagination. As predicted, the relative effect of negative mood on health appraisal was attenuated only among those who imagined a scenario unrelated to health. Furthermore, the pattern of symptom recall data mirrored the self-appraisal findings. The data are consistent with the notion that negative mood can affect subjective appraisals of health by increasing the accessibility of illness-related memories. Implications for diagnostic practice are explored.

Lesions of the middle cerebellar peduncle disrupt acquisition and retention of the rabbit's classically conditioned nictitating membrane response.

Abstract: Rabbits were classically conditioned to emit a nictitating membrane response (NMR) to either a light or tone conditioned stimulus (CS) paired with an eye shock unconditioned stimulus (UCS). They then received lesions of the middle cerebellar peduncle (MCP) or served as unoperated controls. Following surgery, they were given separate presentations of tone, light, and vibratory CSs, each paired with the eye shock UCS. In this way, conditioned responses (CR) to the previously trained light or tone served as a test of retention, whereas CRs to the remaining two conditioned stimuli (tone and vibratory or light and vibratory) served as a test of acquisition. The results of the study revealed that rabbits with complete lesions of the MCP showed disrupted acquisition and retention of the conditioned NMR to all stimuli, rabbits with partial MCP lesions also showed disrupted acquisition and retention to all CSs, but to a lesser degree, and animals with lesions that missed the MCP and unoperated controls both showed normal acquisition and retention of the conditioned NMR. These data are consistent with the view that the cerebellum is an essential part of the circuit for classical conditioning of the NM response and that information about CSs in the auditory, visual, and tactile modalities reach the cerebellum by way of the MCP.

Remaking Japan: The American Occupation As New Deal

Abstract: An absorbing account of the way American New Deal tenets melded with Japanesetradition to form the basis of Japan's modern industrial might.

A theory of public enterprise behavior

Abstract: Unresolved conflict among competing goals induces factions external to public enterprices to intervene in enterprise management, thereby reducing the level of effort expended by managers. Yet intervention can be a rational mechanism for inhibiting managers from capturing the enterprises for their own ends. A formal model explores the equilibrium that results from the interactions between the maximizing decisions of managers and of controllers. The model is extended to analyze strategic buffering by managers and to identify alternative dynamic sequences that might characterize manager-controller interactions. It provides a basis for discussing policy options for controlling public enterprises.

Activity choice: A new approach to economic behavior☆

Abstract: An individual's work and consumption behavior is modeled as the outcome of an optimal choice among activities at each moment within a ‘day’. The model describes the time-shapes of his demand for goods and services, labor supply, and activities within the day and it allows the analysis of choices in which unusually complex motivations are incorporated. It is applicable to questions of job satisfaction, peak demands, shift working and capital utilization, estimation of ‘the value of time’, goal and process utilities, intrinsic and extrinsic satisfactions, ‘labor’ versus ‘labor power’, and to the issues of compulsive consumption and self-control.

Morphological and physiological survival of goldfish Mauthner axons isolated from their somata by spinal cord crush

Abstract: Axon segments isolated from their somata degenerate within days or months depending on species and neuronal type. To better understand the time course of morphological and physiological changes associated with degeneration of axon segments of vertebrate central neurons, we have studied the goldfish Mauthner axon (M-axon) when it has been separated from its soma by spinal cord crush. M-axon segments survive morphologically for at least 77 days at 14°C. Cross-sectional areas of isolated M-axon segments (measured 25–30 mm caudal to the wound site at postoperative days 64 and 77) were greater than those of control axons at the same level. Sheath areas did not change. Electron microscopic observations at the same spinal cord location indicated no clear changes in the configuration or number of neurofilaments or any other organelle. M-axon segments studied morphologically after 87 postoperative days had all degenerated. Mauthner axon segments were capable of conducting action potentials and eliciting ipsilateral EMG responses. Repetitive firing of the M-axon segments elicited EMG responses that fatigued more easily and remained fatigued over a longer interval than did those of control axons. The long duration of M-axon segment survival is unusual in a vertebrate and may be due to the low temperature at which the experiments were conducted (14°C) and/or temperature-independent factors. The increased susceptibility to synaptic depression, which has not reported previously, may represent an early sign of the degenerative process.

High-Frequency Oscillations in the Corona Observed at the 1983 Eclipse

Abstract: We detected excess oscillatory power at 0.25–2.0 Hz in a coronal loop in the 1983 Indonesian total solar eclipse. In this second-generation experiment enlarging upon the work of Pasachoff and Landman (1984), we observed in two frequency channels, one coronal and one continuum, to monitor atmospheric and instrumental effects. We briefly discuss the effects of an oscillation near 1 Hz on the coronal heating problem.

Comparison of acetylcholinesterase and choline acetyltransferase staining patterns in the optic tectum of the goldfish Carassius auratus. A histochemical and immunocytochemical analysis.

Abstract: Although the optic tectum of nonmammalian vertebrates has been extensively studied anatomically, there is little information about the identification of neurotransmitters and the enzymes critical to t

Encrusting corals on a latest Ordovician to earliest Silurian rocky shore, southwest Hudson Bay, Manitoba, Canada

Abstract: Paleozoic tabulate corals are generally thought to have been free standing, a flattened disc-shaped to dome-shaped morphology providing a degree of stability in shallow-water, high-energy environments. The ability to encrust has previously been suggested by patterns of competitive overgrowth in certain species. Definite proof of encrustation by favositid corals is exhibited in an extraordinary example of an ancient rocky shore exposed for 350 m on Hudson Bay near Churchill, Manitoba. Carbonate strata attributed to the Upper Ordovician Port Nelson or Lower Silurian Severn River Formations locally transgress a massive Precambrian quartzite. An ancient shoreface is clearly marked by large, smoothly eroded boulders of the dark quartzite, commonly 2–10 m in diameter. The boulders are buried in coarse carbonate debris, but corals up to 20 cm in diameter are found cemented directly onto the surface of some boulders. Deep pitting of many boulders to a depth of 2–3 cm was contemporaneous and may have been promoted by unpreserved encrusters such as sponges or anemones.

Hyperfine contribution to spin-exchange frequency shifts in the hydrogen maser

Abstract: We have rigorously included hyperfine interactions during electron-spin-exchange collisions between ground-state hydrogen atoms and find additional frequency shifts which are significant for low-temperature atomic hydrogen maser oscillators.

Benthic faunal associations in the Lower Silurian Solvik Formation of the Oslo-Asker Districts, Norway

Abstract: In the Asker District of the Oslo Region there occurs an unusually complete and fossiliferous transition between the uppermost Ordovician and lowermost Silurian, which gives a unique opportunity to assess changes in benthic community structure across the boundary. Seven associations of benthic invertebrates are described from the Solvik Formation (Lower Silurian) of the Oslo Region, Norway. Three of these can be subordinated to a Clorinda and four to a Stricklandia equivalent paleocommunity. These early Silurian paleocommunities succeeded the late Ordovician Onniella paleocommunity, although some associations bearing Stricklandia probably took over the niche of the Nicolella paleocommunity. The faunal associations are subcategories primarily related to lithofacies, while the larger-scale paleocommunities are primarily related to distance from shore. This difference is caused by very eurytopic key-members defining the paleocommunities. These key-members can live in most types of lithofacies, but are otherwise dependent on factors more directly related to depth. The dominance of eurytopic key-members in Early Silurian time was affected by the Ordovician-Silurian extinction period, when a eurytopic life style was a great advantage.

Influence of deformation on pressure-temperature paths of metamorphism

Abstract: Pressure-temperature ( P - T ) paths in structural terranes dominated by folds and thrust faults can be complex and can vary widely within a single metamorphic belt. The complexity and variability of P - T paths result from the advection of heat by folding and thrusting, conductive heat transfer during and after deformation, and the relatively short times for thermal relaxation within folds and thrusts. In fold terranes, contrasting P - T paths are observed between anticlines and adjacent synclines. Cooling paths are observed within anticlines, whereas heating paths are observed within synclines. These different P - T paths result from the folding of isotherms during deformation and the subsequent relaxation of isotherms after deformation. In polydeformed fold terranes, noncoaxial folding results in complex P - T paths over small distances (less than 15 km) within a metamorphic belt because of the repetition of the process of folding and relaxation of isotherms during each folding event In structural terranes dominated by thrust faults, P - T paths differ between major thrust sheets because heat is transferred from the hotter overriding sheet to the cooler lower plate during deformation. Heat transfer during thrusting causes the upper plate to cool and the lower plate to heat. In terranes with multiple thrust sheets, P - T paths can be complex and will depend upon the relative timing of thrust development and the rate at which heat can be transferred from one thrust sheet to the next The P - T paths observed in both the fold and thrust terranes discussed here record relatively short time intervals of 10 5 or 10 6 yr. Because the mineral equilibria respond to small-scale thermal perturbations, there may be a wide variability in P - T paths over a small distance in a metamorphic belt Therefore, before P - T paths are used to reconstruct tectonic histories, both structural and petrologic investigations must be carried out.

Harmonic analysis of periodic extinctions

Abstract: -Fourier analysis of percent extinction data for genera of fossil marine animals during the past 260 million years indicates the existence of a 26 m.y. extinction cycle. The first three harmonics, which account for 51.7 percent of the sum of squares, show the major extinction trends in the late Paleozoic, Mesozoic and Cenozoic. The first ten harmonics, which account for 89.5 percent of the sum of squares, are aligned with eight extinction peaks. The tenth harmonic, with a period of 26 million years, has an amplitude of 6.5 percent and accounts for 12.7 percent of the sum of squares. Several different methods are used to test the validity of the apparent 26 m.y. extinction cycle. Analysis of variance indicated that the 26 m.y. extinction cycle is statistically significant at the 95 percent level. When the 260 m.y. sample interval is divided into equal 130 m.y. segments, the phases and amplitudes for the 26 m.y. cycle were almost equal within the two independent segments. When the 260 m.y. interval is divided into 10 shorter time segments of different lengths, the 26 m.y. cycle is represented in each time segment. A series of experiments is run to test the influence of the Late Permian and Cretaceous peaks on the observed 26 m.y. cycle. When all peaks are smoothed out except for the two major peaks, a pseudo-cycle with a period of 26 m.y. is generated that accounts for 3.0 percent of the sum of squares. When the Permian and Cretaceous peaks are reduced to about half their observed height, the sum of squares accounted for by the 26 m.y. cycle is reduced from 12.7 to 11.0 percent. When the number of extinctions within each stage is used in the harmonic analysis in place of extinction percent, the 26 m.y. cycle accounts for 19.3 percent of the sum of squares. Therefore, the evidence from harmonic analysis of fossil marine animals points toward a distinct and persistent 26 m.y. cycle in mass extinctions in the late Paleozoic, Mesozoic and Cenozoic. William T. Fox. Department of Geology, Williams College, Williamstown, Massachusetts 01267 Accepted: June 1, 1987

Ricardian Equivalence, Liquidity Constraints, and the Yaari-Blanchard Effect: Tests For Developing Countries

Abstract: Adjustment programs in developing countries have emphasized the importance of reducing fiscal deficits in order to improve private sector saving and investment performance. Recent theoretical analyses associated with the Ricardian equivalence proposition, however, suggest that, in the limit, changes in the level of public sector savings may be completely offset by a change in private savings. This offset would occur because changes in the level of government savings imply changes in the level of future taxation, which in turn affects current private sector saving. Empirical tests of the model for a sample of developing economies do not support the equivalence proposition owing to the prevalence of liquidity constraints.

Nautiloid debris oriented by long‐shore currents along a late Ordovician‐early Silurian rocky shore

Abstract: Siphuncular fragments from arminocerid cephalopods are abundant along 350 m of a well defined rocky shore of late Ordovician or early Silurian age exposed near Churchill in northeastern Manitoba, Canada. The paleoshore is composed of the Precambrian Churchill Quartzite, which is dramatically abutted by carbonate strata gently dipping north beneath Hudson Bay. At one end of the exposure, a former sea stack or sea arch extends prominently outward for 15 m perpendicular to the otherwise linear paleoshore. Probably it acted as a natural groin with some influence on local currents and waves. The orientations of 189 siphuncular fragments were recorded and found to be dominantly perpendicular to the trend of the ancient shore. They are far more cylindrical in shape than conical, and are interpreted to have been rolled to their final resting place pushed by long-shore currents. Concentration of nearly 80% of the fragments towards one end of the shore is consistent with transport by long-shore currents. Ripple marks preserved at a different stratigraphic level form a 45-degree angle to the trend of the paleoshore, providing additional evidence that wave trains must have set up long-shore currents from time to time.

Therapists' personalities and their evaluation of three family therapy styles: an empirical investigation

Abstract: This study examined the relationship between beginning therapists' personalities and their evaluations of three divergent family therapy styles. Sixty clinical and counseling psychology students completed the Adjective Checklist (Gough & Heilbrun, 1983) and rated videotaped therapy sessions conducted by Bowen, Minuckin, and Whitaker. Adjective Checklist ratings of each subject were also obtained from three friends/family members. Self-rated personality factors of dominant-masculinity and, to a lesser extent, nurturant-femininity were significant predictors of subjects' ratings of the tapes. Gender was a factor in ranked ratings of the tapes. Other-rated personality traits were not significant predictors. Implications for therapy training and supervision are discussed.