Some characteristics of tactile channels.

The four information-processing channels of glabrous skin have distinct tuning characteristics which appear to be determined in the periphery at the level of sensory receptors and their afferent nerve fibers. The four-channel model [J Acoust Soc Am 84 (1988) 1680] has been updated to include measurement over a wider frequency range of tuning of the P and NP I channels, psychophysically determined by forward-masking and adaptation tuning curve methods. In addition to differences in their tuning, the P and NP channels differ in the following ways: (1) the P channel, but not NP channels, has been found to be capable of temporal summation, which operates by neural integration; (2) the capacity for spatial summation is also an exclusive property of the P channel; (3) sensitivity declines with age at a greater rate in the P channel than in the NP channels; (4) the masking or adaptation of a channel has no effect on the sensitivity of the other channels, although the channels interact in the summation of the perceived magnitudes of stimuli presented to separate channels.

Temporal gap detection in tactile channels.

The ability of observers to detect temporal gaps in bursts of sinusoids or bursts of band-limited noise was measured to assess the temporal acuity of Pacinian (P) and non-Pacinian (NP) tactile information processing channels. The P channel was isolated by delivering high frequency sinusoids or high frequency noise through a large 1.5-cm2 contactor to the thenar eminence.

Sickness and preventive medical behavior.

Using data from two sources, the Health and Retirement Study (HRS) and the Medical Expenditure Panel Survey (MEPS), I analyze the relationship between health status and the likelihood of engaging in medical screening and other preventive behavior. The results show that individuals who are in poorer health are more likely to get flu shots and cholesterol checks, but less likely to have mammograms, pap smears, breast examinations and prostate checks. There is some evidence that suggests that psychological factors such as fear and anxiety may be important reasons why sicker people are less likely to get cancer screens.

Bisexuality: the state of the union.

In many contemporary Occidental societies, bisexuality is paradoxical. Commonly conceived as a combination of heterosexuality and homosexuality, bisexuality as such became conceivable only after the popularization of the hetero/homosexual dichotomy during the late 19th and 20th centuries. Paradoxically, however, the concepts of hetero- and homosexuality, reflecting the cultural belief that an individual's feelings of sexual attraction are naturally directed toward the other sex or, alternatively, toward the same sex, simultaneously renders bisexuality--as an attraction to both genders--inconceivable.

Catecholase activity associated with copper-S100B.

This study addresses the spectroscopic properties and reactivity associated with the copper-loaded form of S100B isolated from bovine brain. Copper(II)-S100B displays EPR features typical of a type II copper center and is shown here to exhibit catecholase activity, the two-electron oxidation of catechols. The steady-state kinetics associated with the oxidation of several catecholamines has been probed in order to further characterize this activity.

Extrauterine incubation of fetal goats applying the extracorporeal membrane oxygenation via umbilical artery and vein.

The fetus is an unstable subject for an isolated physiological and biochemical study. To study the fetus in a controlled and stable environment, a trial was done using 12 goat fetuses. Extrauterine incubation system was devised using an extracorporeal membrane oxygenation system.

The Scaphopoda.

The Scaphopoda are marine infaunal carnivores that feed on foraminiferans and other microorganisms selected and manipulated by their unique feeding tentacles or captacula. Their tusk-like shell is open at both ends; the burrowing foot and captacula protrude anteriorly, while respiratory currents pass through the posterior opening. Although the scaphopods comprise one of the smallest molluskan classes in terms of species diversity, they have a worldwide distribution ranging from intertidal to depths in excess of 6000 m.

A four-channel analysis of the tactile sensitivity of the fingertip: frequency selectivity, spatial summation, and temporal summation.

Thresholds were measured for the detection of vibratory stimuli of variable frequency and duration applied to the index fingertip and thenar eminence through contactors of different sizes. The effects of stimulus frequency could be accounted for by the frequency characteristics of the Pacinian (P), non-Pacinian (NP) I, and NP III channels previously determined for the thenar eminence (Bolanowski et al., J Acoust Soc Am 84: 1680-1694, 1988; Gescheider et al.

Absolute pK(a) determinations for substituted phenols.

The CBS-QB3 method was used to calculate the gas-phase free energy difference between 20 phenols and their respective anions, and the CPCM continuum solvation method was applied to calculate the free energy differences of solvation for the phenols and their anions. The CPCM solvation calculations were performed on both gas-phase and solvent-phase optimized structures. Absolute pK(a) calculations with solvated phase optimized structures for the CPCM calculations yielded standard deviations and root-mean-square errors of less than 0.

From college to clinic: reasoning over memorization is key for understanding anatomy.

Anatomy and physiology are taught in community colleges, liberal arts colleges, universities, and medical schools. The goals of the students vary, but educators in these diverse settings agree that success hinges on learning concepts rather than memorizing facts. In this article, educators from across the postsecondary educational spectrum expand on several points: (1) There is a problem with student perception that anatomy is endless memorization, whereas the ability to manage information and use reasoning to solve problems are ways that professionals work.

Parents' expressiveness and young children's emotion decoding with parents and unknown adults.

The authors investigated young children's ability to decode the emotions of happiness and anger expressed by their parent and an adult stranger. Parents and adult strangers (encoders) were videotaped while describing events that had elicited happiness or anger. Children viewed brief clips edited from these videotapes and indicated the emotion that their parent or the stranger was expressing.

The frequency selectivity of information-processing channels in the tactile sensory system.

The frequency selectivity of the P, NP I, and NP II channels of the four-channel model of mechanoreception for glabrous skin was measured psychophysically by an adaptation tuning curve procedure. The results substantially extend the frequency range over which the frequency selectivity of these channels is known and further confirm the hypothesis that the input stage of each of these channels consists of specific sensory nerve fibers and associated receptors. Specifically, the frequency characteristics of Pacinian nerve fibers, rapidly adapting (RA) nerve fibers, and slowly adapting Type II (SA II) nerve fibers were found to be the peripheral neurophysiological correlates of the P, NP I, and NP II channels, respectively.

Accurate pK(a) calculations for carboxylic acids using complete basis set and Gaussian-n models combined with CPCM continuum solvation methods.

Complete Basis Set and Gaussian-n methods were combined with CPCM continuum solvation methods to calculate pK(a) values for six carboxylic acids. An experimental value of -264.61 kcal/mol for the free energy of solvation of H(+), DeltaG(s)(H(+)), was combined with a value for G(gas)(H(+)) of -6.

Adapting to heart conditions: a test of the hedonic treadmill.

This paper tests the hypothesis of hedonic adaptation by analyzing the role that a history of heart problems has on the ability to deal with future heart conditions. The results show that those who have had a heart condition in the past are less likely to report worse self-assessed health and emotional health due to the onset of a new condition than those who have not previously had exposure to heart trouble. The results are fairly supportive of the notion of a hedonic treadmill.

Planning reaching and grasping movements: the problem of obstacle avoidance.

In this article, we review a model of the movement-planning processes that people use for direct reaching, reaching around obstacles, and grasping, and we present observations of subjects' repeated movements of the hand to touch 2 target locations, circumventing an intervening obstacle. The model defines an obstacle as a posture that, if adopted, would intersect with any part of the environment (including the actor himself or herself). The model finds a trajectory that is likely to bring the end-effector to the target by means of a one-or two- stage planning process.

The politics of certainty: conceptions of science in an age of uncertainty.

The prestige of science, derived from its claims to certainty, has adversely affected the humanities. There is, in fact, a "politics of certainty". Our ability to predict events in a limited sphere has been idealized, engendering dangerous illusions about our power to control nature and eliminate time.

Compressing Spin-Polarized (3)He With a Modified Diaphragm Pump.

Nuclear spin-polarized (3)He gas at pressures on the order of 100 kPa (1 bar) are required for several applications, such as neutron spin filters and magnetic resonance imaging. The metastability-exchange optical pumping (MEOP) method for polarizing (3)He gas can rapidly produce highly polarized gas, but the best results are obtained at much lower pressure (~0.1 kPa).

Steroid regulation of octopamine expression during metamorphic development of the moth Manduca sexta.

Octopamine (OA), a biogenic amine similar to norepinephrine, has profound and well-documented actions on the nervous systems of invertebrates. In the insect, Manduca sexta, we examined the developmental plasticity of OA synthesis, studied its endocrine regulation, and observed previously undescribed OA-immunoreactive (ir) neurons. We found that levels of tyramine beta-hydroxylase (TbetaH), an essential enzyme for the biosynthesis of OA, increase during metamorphosis.

Characterization and developmental regulation of tyramine-beta-hydroxylase in the CNS of the moth, Manduca sexta.

Octopamine (OA) is present in insect nervous tissue, but little is known about its biosynthesis. In the CNS of Manduca sexta, OA levels increase markedly during postembryonic adult development. To study this increase, we developed an assay for tyramine-beta-hydroxylase, the putatively rate-limiting enzyme for OA biosynthesis.

Source monitoring and false recollection: a life span developmental perspective.

In a variation of Deese's (1959, Journal of Experimental Psychology, 58, 17-22) list-learning paradigm, 32 first-graders, 32 younger adults, and 24 older adults self-generated words that were semantically related to study items prior to recall. This manipulation increased false recollection for children and older adults, but not for younger adults. These data suggest that source-monitoring deficits underlie children's and older adults' illusory memories within the list-learning format.

Domains of differential cell proliferation suggest hinged folding in avian gut endoderm.

A profile of proliferative growth assessed with tritium autoradiograms from White Leghorn embryo stages Hamburger-Hamilton 6-21 labeled in ovo presents evidence of hinged folding driven by localized differential cell proliferation in endoderm. There is a significant, bilateral pattern, and differences are most pronounced in axial levels that are folding and rotating. Highest proliferation is in cells producing folds; lowest proliferation is in median cells.

Vibrotactile temporal summation: probability summation or neural integration?

Temporal summation, a decrease in the detection threshold that occurs when either the duration of a stimulus or the number of stimuli in a sequence is increased, has been attributed to the operations of either the mechanism of neural integration or of probability summation. Our experiments indicate that under certain conditions, both mechanisms may operate, but that the process of neural integration is an exclusive characteristic of the Pacinian (P) channel. The P channel was isolated by applying 250 Hz stimuli through a 1.

A Web-accessible tutorial for PsyScope based on classic experiments in human cognition.

PsyScope is a graphically oriented, script-based program for the control of experiments on Macintosh computers that has been made freely available to the psychology community by its developers (Cohen, MacWhinney, Flatt, & Provost, 1993) at Carnegie Mellon University. We describe a graduated tutorial that was written for new users of PsyScope (instructors or students); the text and scripts can be retrieved from a website at Hamilton College (http:/(/)cogito.hamilton.