Showing papers by "University of California, Santa Cruz published in 1981"

A recursive approach to low complexity codes

Abstract: A method is described for constructing long error-correcting codes from one or more shorter error-correcting codes, referred to as subcodes, and a bipartite graph. A graph is shown which specifies carefully chosen subsets of the digits of the new codes that must be codewords in one of the shorter subcodes. Lower bounds to the rate and the minimum distance of the new code are derived in terms of the parameters of the graph and the subeodes. Both the encoders and decoders proposed are shown to take advantage of the code's explicit decomposition into subcodes to decompose and simplify the associated computational processes. Bounds on the performance of two specific decoding algorithms are established, and the asymptotic growth of the complexity of decoding for two types of codes and decoders is analyzed. The proposed decoders are able to make effective use of probabilistic information supplied by the channel receiver, e.g., reliability information, without greatly increasing the number of computations required. It is shown that choosing a transmission order for the digits that is appropriate for the graph and the subcodes can give the code excellent burst-error correction abilities. The construction principles

The Narcissistic Personality Inventory: alternative form reliability and further evidence of construct validity.

Abstract: The aim of this study was twofold: (a)to measure the alternate form reliability of the Narcissistic Personality Inventory, and (b)to determine its construct validity by correlating it with the four scales of the Eysenck Personality Questionnaire (EPQ). The alternate form reliability was .72. The Extraversion and Psychoticism scales of the EPQ were positively and significantly correlated with the narcissism measure, and the Lie scale showed a significant negative correlation. The Neuroticism scale showed a nonsignificant relationship with narcissism. In addition, the combined Extraversion and Psychoticism scales produced[ a Multiple R with the narcissism measure that accounted for significantly more of the variance in narcissism than did either measure alone.

Segregation of cognitive and motor aspects of visual function using induced motion

Abstract: Targets were displaced to cancel an apparent displacement induced by a step motion of a background or were held stationary while appearing to jump in an induced displacement. Target and background were then extinguished, and the subject pointed to the target’s last position. When the target had appeared to move but did not, background position did not significantly affect pointing; when the target had moved but appeared to remain stationary (displacement canceled by opposite induced displacement), pointing depended upon the target’s egocentric position. A similar result was obtained with sinusoidal motion. In terms of a two visual-systems hypothesis, the motor system uses more veridical spatial information and is less affected by relative changes in two retinal signals than is the cognitive system.

Secondary structure model for 23S ribosomal RNA.

Abstract: A secondary structure model for 23S ribosomal RNA has been constructed on the basis of comparative sequence data, including the complete sequences from E. coli. Bacillus stearothermophilis, human and mouse mitochondria and several partial sequences. The model has been tested extensively with single strand-specific chemical and enzymatic probes. Long range base-paired interactions organize the molecule into six major structural domains containing over 100 individual helices in all. Regions containing the sites of interaction with several ribosomal proteins and 5S RNA have been located. Segments of the 23S RNA structure corresponding to eucaryotic 5.8S and 25 RNA have been identified, and base paired interactions in the model suggest how they are attached to 28S RNA. Functionally important regions, including possible sites of contact with 30S ribosomal subunits, the peptidyl transferase center and locations of intervening sequences in various organisms are discussed. Models for molecular 'switching' of RNA molecules based on coaxial stacking of helices are presented, including a scheme for tRNA-23S RNA interaction.

On Ethnographic Surrealism

Abstract: Andre Breton often insisted that surrealism was not a body of doctrines, or a definable idea, but an activity. The present essay is an exploration of ethnographic activity, set, as it must always be, in specific cultural and historical circumstances. I will be concentrating on ethnography and surrealism in France between the two world wars. To discuss these activities together—at times, indeed, to permit them to merge—is to question a number of common distinctions and unities.

Sinking rates of fecal pellets from gelatinous zooplankton (Salps, Pteropods, Doliolids)

Abstract: Sinking rates were determined for fecal pellets produced by gelatinous zooplankton (salps, Salpa fusiformis and Pegea socia; pteropods, Corolla spectabilis; and doliolids, Dolioletta gegenbaurii) feeding in surface waters of the California Current. Pellets from the salps and pteropods sank at rates up to 2 700 and 1 800 m d-1, respectively; such speeds exceed any yet recorded for zooplankton fecal pellets. Fecal pellets of salps were rich in organic material, with C:N ratios from 5.4 to 6.2, close to values for living plankton. The relation between volume and sinking rate indicates that salp and pteropod pellets are slightly less dense than those of pelagic Crustacea; moreover, pellet density varied between different collection dates, probably because of differences in composition. In contrast, doliolid pellets sank at rates up to 208 m d-1, a rate much lower than would be expected from pellet size. Thus, density and sinking rates of pellets are much more variable in zooplankton than would be expected from studies of crustaceans alone. Moreover, the extraordinarily high sinking rates of fecal pellets of salps indicates that these tunicates may be disproportionately important in the flux of biogenic materials during periods when they form dense population blooms.

The ecological basis for the application of traditional agricultural technology in the management of tropical agro-ecosystems

Abstract: The rural inhabitants (campesinos) of the lowland tropical region of southeastern Mexico have managed their traditional agro-ecosystems for centuries with a focus on sustaining yields on a long term basis rather than maximizing them in the short term. Recently introduced agricultural technology in the region has been rapidly displacing and even eliminating local practices in favor of large-scale commercial farming and cattle raising, yet without achieving the production levels originally proposed. This is accompanied by a loss of diversity in local cropping systems, leading to an ever-increasing dependence on imported food products, poorer nutrition, and degradation of natural resources. Modular production units are proposed in order to help achieve once again the diversity and stability of productivity originally characteristic of the traditional agro-ecosystems. The primary focus of the units center around the application of ecological principles with the incorporation of empirical knowledge of varieties and practices still extant in the region. The basic structure of the units is described. The ecological processes seen to be functioning in local agro-ecosystems are also applied in the modular units. This includes high species diversity in both time and space, high rates of biomass accumulation, closed nutrient cycling, and biological control mechanisms for weeds, pests, and disease. The perspectives for such systems of production are discussed.

Microjustice and Macrojustice

Abstract: If every individual in a society has been fairly rewarded, does this guarantee that rewards have been fairly distributed in the society as a whole? Surprisingly, it does not. It is our contention that people use different criteria to assess microjustice (the fairness of rewards to individual recipients) and macrojustice (the aggregate fairness of reward in a society).

Scaling for External Noise at the Onset of Chaos

Abstract: The effect of external noise on the transition to chaos for maps of the interval which exhibit period-doubling bifurcations are considered. It is shown that the Liapunov characteristic exponent satisfies scaling in the vicinity of the transition. The critical exponent for noise is calculated with the use of Feigenbaum's renormalization group approach, and the scaling function for the Liapunov characteristic exponent is obtained numerically by iterating a map with additive noise.

The role of ethylene in the senescence of oat leaves.

Abstract: The evolution of ethylene, both from the endogenous source and from added 1-aminocyclopropane-1-carboxylic acid (ACC), has been followed in close relationship with the senescent loss of chlorophyll from seedling oat leaves. In white light, where chlorophyll loss is slow, the ethylene evolution increases slowly at first, but when the loss of chlorophyll becomes more rapid, ethylene evolution accelerates. CoCl 2 inhibits this increase and correspondingly maintains the chlorophyll content, with an optimum concentration of 10 micromolar. The rapid rate of chlorophyll loss in the dark is slightly decreased by 3-aminoethoxyvinyl glycine (AVG), by cobalt, and slightly stimulated by ACC. The slower chlorophyll loss in white light, however, is almost completely inhibited by silver ions, greatly decreased by cobalt and by AVG, and strongly increased by ACC. Since the chlorophyll loss is accompanied by proteolysis, it represents true senescence. Chlorophyll loss in light is also strongly antagonized by CO 2 , 1% CO 2 giving almost 50% chlorophyll maintenance in controls, while in the presence of added ACC or ethylene gas, the chlorophyll loss is 50% reversed by about 3% CO 2 . The ethylene system in leaves is thus more sensitive to CO 2 than that in fruits. Indoleacetic acid also clearly decreases the effect of ACC. It is shown that kinetin, CO 2 , Ag + , and indoleacetic acid, all of which oppose the effect of ethylene, nevertheless increase the evolution of ethylene by the leaves, and it is suggested that ethylene evolution may, in many instances, mean that its hormonal metabolism is being prevented. Abscisic acid somewhat increases ethylene evolution also, but its action in promoting senescence in light is antagonized only partially by Ag + , Co 2+ , or AVG. For this and a number of other reasons it is concluded that ethylene and abscisic acid both independently control leaf senescence in the light.

Nonmyopic Equilibria in 2×2 Games

Abstract: In this paper we shall define a new concept of equilibrium in elementary normal-form, or matrix, games, based on the idea that players can look ahead and anticipate where a process might end up if they are allowed to make an indefinite number of sequential moves and countermoves from any outcome in a game. We call this concept a nonmyopic equilibrium and shall show how it differs from the more myopic equilibrium concepts of Nash and Stackelberg, which consider only unilateral deviations of players, or single best responses by players to another player’s strategy choice. We shall also point out that solution concepts in cooperative game theory are encumbered by a similar myopia. Because the concept of a nonmyopic equilibrium is a rather subtle one, we shall, after reviewing previous research in section 2, restrict our analysis to 2 x 2 ordinal games, in which each player can rank the four possible outcomes from best to worst. After defining this concept in section 3, and comparing it with other equiIibrium concepts in section 4, we shall show in section 5 that it exists in 37 of the 78 distinct 2 x 2 games (47 percent), generally coinciding with pure-strategy Nash equilibria in these games. In two of the 37 games, however, the nonmyopic equilibria do not

On Self‐Deception

Abstract: T H E P O I N T OF DEPARTURE for this conference is the Clever Hans story. Because the story was written as a scientific treatise, the horse’s trainer, Herr von Osten, appears primarily as a stimulus object. Scientists observed and recorded Herr von Osten’s postural movements and concluded that such movements were signals to the horse to tap his hoof. Although not entirely neglected in the scientific write-up, Herr von Osten’s unshakable belief in the horse’s human-like rationality received only brief notice. Both Stumpfl and Pfungst2 declared that von Osten was not a trickster nor a swindler; rather they settled on a diagnosis of self-deception. Although in its naked form, the term “self-deception” contains a contradiction, it continues to be widely used to denote states of affairs similar to that of Herr von Osten in the Clever Hans story. Herr von Osten held to his anthropomorphic belief in the horse’s rationality in the face of adverse evidence presented by respectable and responsible scientists. Parenthetically, one should note that anthropomorphism is a rather common human belief, and Herr von Osten’s apparent espousal of anthropomorphic doctrine was not taken by his contemporaries as a sign of senile dementia (nor should it have been). My aim in this paper is to illuminate the conduct frequently labeled self-deception. Von Osten is an appropriate example. To show that the phenomenon is not unique, I will identify several additional examples taken from experimental and field studies. These examples, taken together, serve both as a working definition of self-deception and a framework for a sketch of previous attempts to come to grips with the problem. At the end of my paper, I offer a theoretical statement about self-deception based on the narrative as the root-metaphor for knowing.

Temperature Compensation of Circadian Period Length in Clock Mutants of Neurospora crassa.

Abstract: Temperature compensation of circadian period length in 12 clock mutants of Neurospora crassa has been examined at temperatures between 16 and 34°C. In the wild-type strain, below 30°C (the “breakpoint” temperature), the clock is well-compensated (Q10 = 1), while above 30°C, the clock is less well-compensated (Q10 = 1.3). For mutants at the frq locus, mutations that shorten the circadian period length (frq-1, frq-2, frq-4, and frq-6) do not alter this temperature compensation response. In long period frq mutants (frq-3, frq-7, frq-8), however, the breakpoint temperature is lowered, and the longer the period length of the mutants the lower the breakpoint temperature. Long period mutants at other loci exhibit other types of alterations in temperature compensation—e.g. chr is well-compensated even above 30°C, while prd-3 has a Q10 significantly less than 1 below 30°C. Prd-4, a short period mutant, has several breakpoint temperatures. Among four double mutants examined, the only unusual interaction between the individual mutations occurred with chr prd, which had an unusually low Q10 value of 0.86 below 27°C. There was no correlation between circadian period length and growth rate. These strains should be useful tools to test models for the temperature compensation mechanism.

Diagenetic trends in the siliceous facies of the Monterey Shale in the Santa Maria region, California

Abstract: X-ray diffraction and oxygen isotopic analyses of outcrop and subsurface samples of siliceous rocks were used to reconstruct thermal and diagenetic histories of the Miocene Monterey Shale near Santa Maria, California Within many stratigraphic sections soft, porous diatomaceous rocks change gradationally to underlying hard and brittle chert, porcellanite, and siliceous shale; the accompanying silica mineral zones are, in descending stratigraphic order: (1) biogenic silica (opal-A), (2) cristobalitic silica (opal-CT), and (3) microcrystalline quartz Boundaries between silica mineral zones and stratigraphic horizons are often discordant Within the opal-CT zone, the d(101)-spacing of opal-CT decreases in a smooth non-linear fashion from about 4 10 A to 4-04 A In the Santa Maria Valley and Bradley oil field areas the thicknesses of the opal-CT zones are greater and the present thermal gradients less than in the adjacent Orcutt oil field Thin opal-CT zones at shallow maximum burial depths apparently correlate with higher thermal gradients Using present thermal gradients and reconstructed maximum burial depths from well data in the Santa Maria region, the ranges in temperatures for the top and base of the opal-CT zone are 38–54 °C and 55–110 °C, respectively The temperature difference between these two boundaries ranges from 17 to 60 °C In comparison, temperature ranges for these two boundaries computed from oxygen isotopic compositions of opal-CT and quartz, extrapolated experimental quartz-water fractionations, and assuming δO18= 0%o for the isotopic composition of the equilibrating fluid are 18–56 °C and 31–80 °C for the top and base of the opal-CT zone, respectively The temperature difference between these boundaries is 11–36 °C using this method Thermal gradients and sedimentation rates strongly influence rates of silica transformations Reconstructed thermal and diagenetic histories of siliceous rocks of the Monterey Shale at four well sites in the Santa Maria region demonstrate that most silica conversions probably occurred during the last 3–4 Myr in response to accelerated rates of sedimentation (and therefore burial heating) during the Pliocene

Differential feeding and fecal pellet composition of salps and pteropods, and the possible origin of the deep-water flora and olive-green “Cells”

Abstract: Salps (mainly Salpa fusiformis and, to a lesser extent, Pegea socia) and a web-building pteropod (Corolla spectabilis) were studied in epipelagic waters of the central California Current. Although both kinds of gelatinous zooplankton trap phytoplankton in a mucus net, a fecal pellet analysis indicated that their diet differs significantly when they feed together, probably because of differences both in the pore sizes of their nets and in their feeding methods. Salps have a finemesh filter, on which they can retain even the smallest phytoplankton; thus, when small coccolithophores are abundant, as they were in our study, salp feces contain such cells and the coccoliths derived from them. In contrast, pteropods feeding in the same area produce fecal pellets consisting chiefly of larger phytoplankton, especially diatoms. Since fecal pellets transport most biogenic material to the deep sea, changes in herbivore species composition at a given geographic location can change the chemistry of materials entering deep water; at our study site, the more salps, the greater the calcite flux, and, the more pteropods, the greater the silica flux. In addition, fecal pellets of both salps and pteropods include partially digested residues of phytoplankton that appear as olive-green spheres, having an ultrastructure identical with that of the socalled olive-green “cells.” Presumably, fecal pellets, after sinking into deep water, ultimately disintegrate. releasing both the viable phytoplankton and the olive-green spheres into aphotic waters. Thus the feces of epipelagic herbivores are likely sources of much of the flora of the deep ocean.

The asymmetric transmembrane distribution of phosphatidylethanolamine, phosphatidylserine, and fatty acids of the bovine retinal rod outer segment disk membrane

Abstract: The transmembrane distribution of the major aminophospholipids in the bovine retinal rod outer segment disk membrane, phosphatidylethanolamine and phosphatidylserine, was determined using a novel pair of permeable and impermeable covalent modification reagents. The values for the percentages of phosphatidylethanolamine and phosphatidylserine in the outer monolayer were calculated from a simple expression which takes into account the leakage of impermeable reagent into the disk lumen as monitored by the extent of labeling of lysine entrapped in the lumen. We infer from our results that at least 73 to 87% of the disk phosphatidylethanolamine and 77 to 88% of the disk phosphatidylserine are in the outer disk membrane monolayer. The fatty acid composition of the inner aminophospholipids is slightly more saturated than the outer aminophospholipids. Calculations using the lateral surface areas occupied by the disk membrane lipids suggest that 65 to 100% of the disk phosphatidylcholine is on the inner membrane surface. Since the disk phosphatidylcholine is also somewhat more saturated than the phosphatidylethanolamine and phosphatidylserine of the outer monolayer, the total inner membrane monolayer fatty acid composition is more saturated than that of the outer monolayer fatty acid composition.