Showing papers by "University of California, Santa Cruz published in 1975"

Programming-in-the-Large Versus Programming-in-the-Small

Abstract: We distinguish the activity of writing large programs from that of writing small ones. By large programs we mean systems consisting of many small programs (modules), possibly written by different people.We need languages for programming-in-the-small, i.e. languages not unlike the common programming languages of today, for writing modules. We also need a “module interconnection language” for knitting those modules together into an integrated whole and for providing an overview that formally records the intent of the programmer(s) and that can be checked for consistency by a compiler.We explore the software reliability aspects of such an interconnection language. Emphasis is placed on facilities for information hiding and for defining layers of virtual machines.

Programming-in-the large versus programming-in-the-small

Abstract: We distinguish the activity of writing large programs from that of writing small ones. By large programs we mean systems consisting of many small programs (modules), possibly written by different people.We need languages for programming-in-the-small, i.e. languages not unlike the common programming languages of today, for writing modules. We also need a “module interconnection language” for knitting those modules together into an integrated whole and for providing an overview that formally records the intent of the programmer(s) and that can be checked for consistency by a compiler.We explore the software reliability aspects of such an interconnection language. Emphasis is placed on facilities for information hiding and for defining layers of virtual machines.

Morphology and genesis of nodular chalks and hardgrounds in the Upper Cretaceous of southern England

Abstract: The Upper Cretaceous chalks of southern England are a thick sequence of rhythmically bedded, bioturbated coccolith micrites, deposited in an outer shelf environment in water depths which varied between 50 and 200–300 m. The products of sea floor cementation are widely represented in the sequence, and a series of stages of progressive lithification can be recognized. These began with a pause in sedimentation and the formation of an omission surface, followed by (a) growth of discrete nodules below the sediment-water interface to form a nodular chalk, erosion of which produced intraformational conglomerates. (b) Further growth and fusion of nodules into continuous or semicontinuous layers: incipient hardgrounds. (c) Scour, which exposed the layer as a true hardground. At this stage, the exposed lithified chalk bottom was subject to boring and encrustation by a variety of organisms, whilst calcium carbonate was frequently replaced by glauconite and phosphate to produce superficial mineralized zones. In many cases, the processes of sedimentation, cementation, exposure and mineralization were repeated several times, producing composite hardgrounds built up of a series of layers of cemented and mineralized chalk, indicating a long and complex diagenetic history. Petrographic study of early cemented chalks indicates lithification was the result of the precipitation of small crystals on and between coccoliths and coccolith fragments. By analogy with known occurrences of early lithification in Recent deeper water carbonates, the cement is believed to have been either high magnesian calcite or aragonite, and more probably the former. The vast scale of operations involved in the cementation process precludes carbonate in expelled pore fluids as the source of cement, whilst quantities of aragonite incorporated in sediment are also inadequate. This, plus the observed association of horizons of early lithification with pauses in sedimentation associated with omission surfaces suggests seawater as a source of cementing materials. Stratigraphic studies indicate that processes of early lithification leading to hardground formation proceeded to completion in intervals to be measured in tens or hundreds of years. Regional studies suggest that early lithification characterized relatively shallow water phases associated with regional regression over the whole of the area, whilst in detail, the distribution of mature mineralized hardground complexes is strongly correlated with sedimentary thinning and condensation over small areas and the buried flanks of massifs. Early cementation in more basinal areas is typically in the form of nodular developments and incipient hardgrounds, whilst day contents in excess of a few percent appear to have inhibited early lithification. The striking rhythmicity of hardgrounds and nodular chalks is no more than a particular expression of the overall rhythmicity of chalk sequences. The stage of early lithification reached in any instance is dependent on sediment type, the time interval represented by the associated omission surface and the degree of associated scour and erosion (if any). Chalk hardgrounds differ from most others described in the geological literature in their widespread distribution (individual hardgrounds may cover up to 1500 km2), the presence of striking glauconite and phosphate replacements of lithified carbonate matrices, their frequently sparse epifaunas, and boring infaunas dominated by clionid sponges. These differences reflect the deeper water shelf setting of the chalk, and the more open marine, oceanic circulatory system, both strikingly different from the setting of other, shallower water hardgrounds. Litho- and biostratigraphic variation in the chalk sequences of the area studied are summarized in an appendix.

First-Order Phase Transitions in Renormalization-Group Theory

Abstract: Conditions are given for the renormalization-group transformations of the Hamiltonian of a thermodynamic system which lead to a discontinuity in an order parameter.

Growth Zones in the Echinoid Skeleton

Abstract: Growth zones in echinoid skeletal ossicles are mainly the result of differences in structural characteristics. In the test plates, opaque zones, which appear light in reflected light, dark in transmitted light, and are X-ray dense, have relatively larger trabecules and smaller intertrabecular channels. Translucent zones, which appear dark in reflected light, light in transmitted light, and are less X-ray dense, have relatively smaller trabecules and larger intertrabecular channels. Organic material in the plates, especially when pigmented or charred, enhances the appearance of the growth zones. Opaque zones result from relatively fast plate growth while translucent zones result from relatively slow plate growth; food deprivation leads to the formation of translucent zones. The growth zones appear to be formed seasonally, at least in some cases, probably in relation to seasonal changes in growth rates, and perhaps in relation to seasonal reproductive activity

The Structure of Plant Cell Walls: VII. Barley Aleurone Cells

Abstract: The walls of barley (Hordeum vulgare var. Himalaya) aleurone cells are composed of two major polysaccharides, arabinoxylan (85%) and cellulose (8%). The cell wall preparations contain 6% protein, but this protein does not contain detectable amounts of hydroxyproline. The arabinoxylan has a linear 1,4-xylan backbone; 33% of the xylosyl residues are substituted at the 2 and/or 3 position with single arabinofuranosyl residues. The results of in vitro cellulose binding experiments support the hypothesis that noncovalent bonds between the arabinoxylan chains and cellulose fibers play a part in maintaining wall structure. It is suggested that bonding between the arabinoxylan chains themselves is also utilized in forming the walls.

The orthoenstatite to clinoenstatite transformation by shearing and reversion by annealing: Mechanism and potential applications

Abstract: Clinoenstatite (CE) was produced by deforming single-crystal specimens of ortho-enstatite (OE) in several different sorta of experiments. Examination with light and trans-mission electron microscopes shows that the transformation is coherent and involves a macroscopic shear on (100) [001] through an angle of 12.8±1.3 °, in good agreement with the theoretically expected value of 13.3 °, and that the transformation is accomplished by glide on (100) of partial dislocations with b= 0.83[001]. Structural analysis provides further insight into the transformation mechanism. Reversion occurs in specimens annealed under a variety of conditions, and thin lamellae of CE in unconstrained, low-strain specimens recover their original shape during transformation back to OE. Our experiments and thermodynamic estimates both suggest that the equilibrium transition temperature is raised roughly 300 ° C per kilobar of shear stress on (100) [001]. This provides the basis of a method by which it may be possible to determine the magnitude as well as the orientation of the principal stresses that produce CE in nature during deformation of enstatite-bearing rocks.

An accelerating Universe

Abstract: New data on the Hubble diagram, combined with constraints on the density of the Universe and the ages of galaxies, suggest that the most plausible cosmological models have a positive cosmological constant, are closed, too dense to make deuterium in the big bang, and will expand for ever. Possible errors in the supporting arguments are discussed.

Eye movements and visual perception: A “two visual system” model*

Abstract: Eye movement is one of the few externally measurable activities of visual perception, and provides a checkpoint for models of perceptual processes. Here the model of Arbib & Didday (1971) is compared with that of Noton & Stark (1970, 1971 a , b ), and is found to predict the same behavior but without requiring explicit storage of eye movement commands.

Geophysical Study of the Venezuelan Borderland

Abstract: The Venezuelan Borderland is composed of several large depositional basins, a linear chain of islands, and a broad outer ridge. It is cut by a nearshore zone of east-trending faults. Geophysical profiles show that the basins have different structural styles, but these features and the large faults and ridges are related to each other and to the Caribbean Coast Range by a complex history of relative movement between the Caribbean and South American plates since Late Cretaceous time. The east-trending Curacao Ridge is a thick pile of deformed low-density strata ( Vc ⩽4.1 km/sec ) that apparently formed by compression of Venezuela Basin strata on its north side and by deposition and compression of strata in Los Roques Trough on the south. The basement rock of the Netherlands Antilles is composed of diabase, pillow basalt, and marine sediment that are weakly metamorphosed and cut by quartz dioritic intrusives. Gravity models suggest a thick (32 km) root beneath the islands and a thinned (18 km) crust beneath the Bonaire Trough. The Bonaire Trough probably formed by movement of the island chain away from the mainland in middle Tertiary time but shows little sign of present-day tectonic activity. The Cariaco Trench is an extensional basin between the San Sebastian and El Pilar faults. The Curacao Ridge is widest and thickest in the west (70° W.), where sediment to the north in the Venezuela Basin is thin. The ridge is narrow in the east (66° W.), where sediment of the Venezuela Basin is thick (up to 4 km). No compressional deformation of the basin sediment is seen east of Los Roques Canyon. This structure may be explained by clockwise rotation of a small crustal block — the Bonaire block — about a pole near Caracas. The rotation of the Bonaire block probably results from dextral movement between the much larger Caribbean and South American plates. The very low seismicity recorded near the Curacao Ridge may result from a combination of low rate of deformation and low elastic strain release involved in deforming a large sediment body.

Emotional responses of women following therapeutic abortion

Abstract: Factor analysis of post-abortion emotional responses revealed three factors. Negative emotions split into two factors: socially-and internally-based. Positive emotions, constituting the third factor, were experienced most strongly. Correlations with background variables suggest two influences on response: the woman's social environment and her internalized concerns about the abortion.

The Metabolism of Oat Leaves during Senescence

Abstract: The senescence of the first leaves of light-grown Avena seedlings when detached and placed in the dark is inhibited by α, α′-dipyridyl and α, α′, α″-tripyridyl at concentrations between 10−5 and 10−4 M. Five other chelating agents exert similar inhibiting effects at concentrations 3 to 30 times higher. The senescence of etiolated leaves, as shown by loss of carotenoid and protein, is similarly inhibited. Ethylene-diaminetetraacetate has a similar effect in the dark, though only at 10 mM and above, but in the light it causes bleaching of chlorophyll. It is deduced that an iron-containing system plays an essential part in the initiation of the senescence process.

Niche specialization and species diversity along a California transect.

Abstract: The structure of the food-web at the flower-herbivore interface was examined along a transect of fourteen communities across central California. All results are commensurate with the hypothesis that in most environments there is selective pressure towards specialization. However, it is only in the most predictable or stable environments that the resultant diminishment of behavioral and genetic flexibility is in a sense "permitted" by subsequent natural selection. In the most extreme environments, behavioral specialization may be a necessary prerequiste permitting briefly thriving ephemeral populations which must recolonize frequently. The data results indicate: 1) Total species number increases with stability and predictability of the climate; 2) As the climate ameliorates, niche-specialization is a progressively more successful strategy; 3) The percentage of niche-specialized species of both plants and flower-feeding herbivores increases in the most severe environments at the expense of the more moderately specialized species; 4) Energetic flow chart redundancy increases in extreme environments; 5) Especially important to an understanding of pollination interactions is the fact that similar physiognomic communities at very different altitudes are in all cases much more similar than different community types within a research site.

Morphology and genesis of nodular phosphates in the Cenomanian Glauconitic Marl of south‐east England

Abstract: Phosphatic nodules are abundant in the Glauconitic Marl (Cretaceous, Cenomanian) of south-east England, particularly where the sequence is condensed. Some of the nodules are derived from the underlying Upper Greensand, and are phosphatic fossil fragments, fossil moulds, and calcareous concretions. Concretions in particular show signs of a complex history of multiple phases of boring, encrustation, phosphatisation, and glauconitisation. Phosphate and glauconite are both replacements after fine-grained carbonate sediment and cement. The majority of the phosphates are whole and fragmentary moulds of fossils. The origin of theses nodules involved: (1) infilling of shells, (2) burial, (3) prefossilisation-cementation of fossil infillings. probably by high magnesian calcite, (4) dissolution of aragonitic shell material, (5) disinterment and exposure of moulds on the sea floor, followed by (6) phosphatisation. boring. and enerustation by various organisms, and sometimes glauconitisation. Many nodules bear evidence of several cycles of cementation, exposure, mineralisation, boring and enerustation. The closest Recent analogues to the Glauconitic Marl phosphates appear to be the phosphatic crust and nodules forming today off the coast of southern California. The features described and processes inferred from the Glauconitic Marl occurrences appear to have been widespread in nodular phosphatic facies.

An introduction to the issues

Abstract: Substantial questions have been raised; only expanded research and development efforts can provide answers beyond serious dispute

Bioenergetic functions of sleep and activity rhythms and their possible relevance to aging

Abstract: The hypothesis is proposed that sleep constitutes a period of dormancy in which energy is conserved to partially offset the increased energy demands of homeothermy. Phylogenetic data indicate that the complete physiological and behavioral manifestations of sleep are unique to homeotherms; furthermore “ontogeny recapitulates phylogeny” in the parallel development of slow wave sleep and thermoregulation as exemplified in the opossum. Thus, sleep constitutes a state of reduced metabolism that may represent a variation on the theme of dormancy, functionally lying on a continuum of energy conservation processes, ranging from inactivity and estivation to torpor and hibernation. The high amounts of sleep in infancy may involve conservation of energy and its consequent availability for growth. Decreased amounts of stage 4 and total sleep with aging in humans may represent reduced energy demands reflected by parallel declines in basal metabolic rate and physical activity. Disruptions of circadian rhythms of sleep and wakefulness in humans produce impairments in mood and performance independent of total amounts of sleep obtained, and reduce the amplitude of physiological rhythms. It is suggested that aging processes might also be affected by such disruptions in activity rhythms. Berger, R. J. Bioenergetic functions of sleep and activity rhythms and their possible relevance to aging. Federation Proc. 34: 97–102, 1975.

Magnetic-monopole solution of non-Abelian gauge theory in curved spacetime

Abstract: A magnetic-monopole solution of a non-Abelian gauge theory as proposed by 't Hooft is studied in curved spacetime. Einstein's equations are solved for the case of a magnetic point charge yielding a metric identical to the Reissner-Nordstr\"om metric, except that a nonvanishing cosmological constant is invoked.

Circadian periodicity a neurospora: alteration by inhibitors of cyclic AMP phosphodiesterase.

Abstract: Three methyl xanthine inhibitors of adenosine 3',5'-monophosphate phosphodiesterase-theophylline, aminophyline, and caffeine-lengthen the period of the circadian conidiation rhythm of Neurospora. The effect are seen in wild-type strains and in three mutant strains with genetically altered period lengths. These results suggest the possible involvement of adenosine 3', 5'-monophosphate in the control of circadian rhythmicity.

The Metabolism of Oat Leaves during Senescence: III. The Senescence of Isolated Chloroplasts

Abstract: The changes in chlorophyll and protein in senescing chloroplasts isolated from the first leaves of 7-day-old oat ( Avena sativa ) seedlings have been investigated. In darkness the chlorophyll in these plastids is highly stable, losing only 5 to 10% of its content after 7 days at 26 C. This result contrasts with the behavior of chlorophyll in intact leaves, in which about 80% of the pigment would have disappeared in that time. The protein is less stable than the chlorophyll, though more stable than in the leaf; probably a small amount of protease is present in the plastids. Some protein is also being synthesized in the chloroplasts along with its breakdown; gains of up to 38% in protein and 13% in chlorophyll were observed under different conditions. l-Serine, which actively promotes senescence in the leaf, has only a very slight effect on the chloroplasts, and kinetin antagonizes it. Kinetin also has a small but significant effect in preserving the protein from breakdown. Acid pH somewhat promotes the breakdown, both of chlorophyll and protein. A loss of chlorophyll and protein comparable to that occurring in the senescence of the leaf could not be induced in the chloroplasts by suspending them in malate, in cytoplasmic extract, or in any of a number of enzymes tested alone. Incubation with a mixture of four enzymes was the only treatment which approximated the senescent process in the leaf, causing 34% loss of chlorophyll at pH 5 and 40% loss of protein at pH 7.4, both in 72 hours. In white light, the chlorophyll and the carotenoids, but not the protein, disappear rapidly. This disappearance was shown to be prevented in an atmosphere of nitrogen or in air by a number of reducing agents, of which ascorbic acid was the most effective. It is, therefore, ascribed to photooxidation rather than to normal senescence.

The development of microbodies (glyoxysomes and leaf peroxisomes) in cotyledons of germinating watermelon seedlings.

Abstract: The ontogeny of glyoxysomes and leaf peroxisomes has been examined in the cotyledons of germinating watermelon (Citrullus vulgaris) seedlings. Organelles from the cotyledons were extracted by razor blade homogenization and microbodies were separated by sucrose density gradient fractionation. Both kinds of microbodies have the same mean equilibrium density on sucrose gradients.The development of leaf peroxisomes was examined in seedlings transferred to light at 4 days and 10 to 12 days. In seedlings maintained in darkness to the age of 10 to 12 days, glyoxysomal enzymes virtually disappeared, and the losses were paralleled by a corresponding loss in microbody protein. During this period peroxisomal activity was low and changed only slightly. On transfer to light at this stage, the activity of peroxisomal enzymes rose strikingly. The residual glyoxysomal activity disappeared completely, and the developmental pattern of microbody catalase and microbody protein paralleled the light-induced glyoxysomal disappearance.Similar patterns of microbody development were observed when 4-day-old dark-grown seedlings with maximum glyoxysomal activities were exposed to light. The activity of the peroxisomal enzymes increased and the glyoxysomal enzymes disappeared at a faster rate than in darkness. These changes were again paralleled by the accelerated demise of microbody catalase and microbody protein. Thus under both conditions glyoxysomes were selectively destroyed during peroxisomal development, and the amount of peroxisomes produced was insufficient to offset the loss of glyoxysomal protein. The results do not support the contention that glyoxysomes are transformed to leaf peroxisomes in developing cucurbit cotyledons and favor the view that the two kinds of microbody arise independently of each other.

Social Problems and Deviance: Some Parallel Issues.

Abstract: This paper explores parallel developments in labeling theory and in the value-conflict approach to social problems. Similarities in their critiques of functionalism and etiological theory as well as their emphasis on the definitional process are noted. In addition, the failure of both formulations to develop the distinctiveness of their common insight is examined. An analysis of this failure is presented.

The habitat of Salpa fusiformis in the California Current as defined by indicator assemblages1

Abstract: Indicator assemblages can define the habitat of a planktonic species Diatom assemblages that co-occur with Salpa fusiformis, a common planktonic herbivore, suggest a constancy in the environment of this tunicate: S fusiformis is found with a suite of diatoms whose relative abundances are predictable to a degree Preliminary results indicate that swarm formation by S fusiformis occurs in waters different from that of other salp species commonly found in the California Current