Showing papers by "University of California, Santa Cruz published in 1982"

Supersymmetry, Cosmology, and New Physics at Teraelectronvolt Energies

Abstract: If one assumes a spontaneously broken local supersymmetry, big-bang cosmology implies that the universe is filled with a gravitino (${g}_{\frac{3}{2}}$) gas---possibly its dominant constituent. From the observational bound on the cosmological mass density it follows that ${m}_{{g}_{\frac{3}{2}}}\ensuremath{\lesssim}1$ keV. Correspondingly, the supersymmetry breaking parameter $F$ satisfies $\sqrt{F}\ensuremath{\lesssim}2\ifmmode\times\else\texttimes\fi{}{10}^{3}$ TeV, requiring new supersymmetric physics in the teraelectronvolt energy region. An exact sum rule is derived and used to estimate the threshold and cross section for the production of the new states.

Deoxyglucose analysis of retinotopic organization in primate striate cortex

Abstract: We have anatomically analyzed retinotopic organization using the 14C-labeled 2-deoxy-D-glucose method. The method has several advantages over conventional electrophysiological mapping techniques. In the striate cortex, the anatomical substrate for retinotopic organization is surprisingly well ordered, and there seems to be a systematic relationship between ocular dominance strips and cortical magnification. The 2-deoxyglucose maps in this area appear to be largely uninfluenced by known differences in long-term metabolic activity. This method should prove useful in analyzing retinotopic organization in various visual areas of the brain and in different species.

Selenium in reducing waters.

Abstract: The analysis of selenium species in reducing waters provides important insight into the element's biogeochemical cycle. The absence of selenate and selenite in reducing waters suggests that some removal mechanism could be operative, but the presence in these waters of about 1 nanomole per liter of dissolved organic selenide indicates that the regeneration of selenium in the form of organic species may be the dominant process. The data demonstrate that the regenerative and biogeochemical cycles of selenium are quite complex.

Galaxy formation by dissipationless particles heavier than neutrinos

Abstract: In a baryon dominated universe, there is no scale length corresponding to the masses of galaxies. If neutrinos with mass 50 eV without exceeding the observational mass density limit. A candidate particle is the gravitino, the spin 3/2 supersymmetric partner of the graviton, which has been shown1 to have a mass ≲1 keV if stable2. The Jeans mass for a 1-keV noninteracting particle is ∼1012 M⊙, about the mass of a typical spiral galaxy including the nonluminous halo. We suggest here that the gravitino dominated universe can produce galaxies by gravitational instability while avoiding several observational difficulties associated with the neutrino dominated universe.

Offscraping and underthrusting of sediment at the deformation front of the Barbados Ridge: Deep Sea Drilling Project Leg 78A

Abstract: On Leg 78A we drilled Sites 541 and 542 into the seaward edge of the Barbados Ridge complex, and Site 543 into the adjacent oceanic crust. The calcareous ooze, marls, and muds at Sites 541 and 542 are lithologically and paleontologically similar to the upper strata at Site 543 and are apparently offscraped from the down-going plate. A repetition of Miocene over Pliocene sediments at Site 541 documents major thrust or reverse faulting during offscraping. The hemipelagic to pelagic deposits offscraped in the Leg 78A area include no terrigenous sand beds, but they contain numerous Neogene ash layers derived from the Lesser Antilles Arc. Hence, this sequence is quite unlike the siliciclastic-dominated terranes on land that are inferred to be accretionary complexes. The structural fabric of the offscraped deposits at Sites 541 and 542 is disharmonic, probably along a decollement, with an underlying acoustically layered sequence, suggesting selective underthrusting of the latter. The acoustically layered sequence correlates seismically with pelagic strata cored at Site 543 on the incoming oceanic plate. Cores recovered from the possible decollement surface at both Sites 541 and 542 show scaly foliation and stratal disruption. Approximately lithostatic fluid pressure measured in the possible decollement zone probably facilitates the underthrusting of the pelagic sediments beneath the offscraped deposits. In the incoming section, a transition from smectitic to radiolarian mud with associated increases in density and strength probably controls the structural break between offscraped and underthrust strata. In the Leg 78A area, the underthrust pelagic section can be traced seismically at least 30 km arcward of the deformation front beneath the Barbados Ridge complex.

Sexual reproduction in solitary corals: Overlapping oogenic and brooding cycles, and benthic planulas in Balanophyllia elegans

Abstract: The temperate solitary coral Balanophyllia elegans Verrill, 1864 was collected monthly between January 1977 and August 1978 off the California coast. B. elegans reproduces only sexually, is gonochoric, and broods its embryos. Males are ripe only in late summer, but oocytes and embryos (ca. 40 per female) are found throughout the year. The presence of oocytes and embryos throughout the year may be the result of very long, overlapping oocyte growth and embryonic developmental times. Large, crawling, benthic planulas are released mainly in the winter. The skeletal design of the corallum of B. elegans accommodates the brooding of unusually large embryos; this design may be indicative of brooding large embryos in other species of corals, particularly dendrophyllids.

Foraging strategies and prey switching in the California sea otter.

Abstract: Southern sea otters (Enhydra lutris nereis), in recovering from near extinction, are gradually extending their range to include areas from which they have been absent for more than one hundred years. This study took advantage of the otters' relatively sudden arrival in the area near Santa Cruz, California, to monitor their prey selection in the first two years of residence there. Foraging observations revealed that sea urchins (Strongly-locentrotus franciscanus) were heavily preyed upon initially, but virtually disappeared from the diet after one year of sea otter residence. The disappearance of sea urchins was accompanied by an increased use of kelp crabs (Pugettia producta) and the appearance of clams (Gari californica) in the otters' diet. Abalones (Haliotis rufescens) and cancer crabs (Cancer spp.) remained fairly stable as dietary items throughout the two year period. An electivity index was used to quantify sea otter preferences, which corresponded closely with a ranking scheme based on energy intake/unit foraging time calculated for each major prey species. As predicted by optimal foraging theory, sea otters prefer food species of high rank and replace depleted dietary items with those of next highest rank. The process of dietary switching was analyzed with respect to foraging success rates, and it appears that poor success rates, associated with predation on an increasingly rarer prey species (sea urchins), drive sea otters to hunt for different prey. Both patch selection and search image formation appear to function in this process. The potential effects on community structure and stability of predators exhibiting a preference for the most profitable prey are discussed.

Lysis gene expression of RNA phage MS2 depends on a frameshift during translation of the overlapping coat protein gene

Abstract: Translation of the lysis cistron of MS2 RNA requires a frameshift of ribosomes reading the upstream coat protein mRNA. The out-of-phase fraction of ribosomes terminates at either one of two nonsense codons just preceding the lysis cistron. Termination is followed by initiation at the start codon of the lysis protein message.

Efficient Computation of LALR(1) Look-Ahead Sets

Abstract: Two relations that capture the essential structure of the problem of computing LALR(1) look-ahead sets are defined, and an efficient algorithm is presented to compute the sets in time linear in the size of the relations. In particular, for a PASCAL grammar, the algorithm performs fewer than 15 percent of the set unions performed by the popular compiler-compiler YACC. When a grammar is not LALR(1), the relations, represented explicitly, provide for printing useroriented error messages that specifically indicate how the look-ahead problem arose. In addition, certain loops in the digraphs induced by these relations indicate that the grammar is not LR(k) for any k. Finally, an oft-discovered and used but incorrect look-ahead set algorithm is similarly based on two other relations defined for the fwst time here. The formal presentation of this algorithm should help prevent its rediscovery.

Symbolic Dynamics of One-Dimensional Maps: Entropies, Finite Precision, and Noise

Abstract: In the study of nonlinear physical systems, one encounters apparently random or chaotic behavior, although the systems may be completely deterministic. Applying techniques from symbolic dynamics to maps of the interval, we compute two measures of chaotic behavior commonly employed in dynamical systems theory: the topological and metric entropies. For the quadratic logistic equation, we find that the metric entropy converges very slowly in comparison to maps which are strictly hyperbolic. The effects of finite precision arithmetric and external noise on chaotic behavior are characterized with the symbolic dynamics entropies. Finally, we discuss the relationship of these measures of chaos to algorithmic complexity, and use algorithmic information theory as a framework to discuss the construction of models for chaotic dynamics.

Photoperiodic regulation of gametogenesis and gonadal growth in the sea star Pisaster ochraceus

Abstract: A photoperiod regime 6 mo out of phase between December 1978 and August 1980 resulted in gametogenesis, gonadal growth, and spawning in laboratory-maintained sea stars [Pisaster ochraceus (Brandt)] 6 mo out of phase with individuals in the field or laboratory on normal celestial photoperiods at Santa Cruz, California (USA). The seasonal fluctuation of pyloric cecum size also was shifted when the sea stars were held on the out-of-phase photoperiod regime. Phase shift of all these events was evident within 6 to 9 mo. Long daylengths (or short nightlengths) in spring and summer apparently synchronize or entrain the initiaion of gametogenesis and gonadal growth in fall.

Mother-pup separation and adoption in northern elephant seals

Abstract: The evolution of fostering behavior, parental care directed toward another's young, has been the focus of much recent interest. During a five-year study of northern elephant seals (Mirounga angustirostris) at Ano Nuevo, California, we recorded the frequency of mother-pup separation, reunion, and adoption of orphaned pups in crowded and low-density breeding areas. While most females nursed their own pup exclusively until it was weaned, many females, especially young mothers (age 3–5 years), were unable to raise a pup successfully. In the crowded main breeding harem on Ano Nuevo Island, 24 to 47 percent of the pups born each year were separated from their mothers from 1977 to 1980. Mother-pup separation and pup mortality were associated with the following inter-related factors: 1) female density; 2) weather and tidal conditions; 3) topographical features of the breeding areas (i.e., degree of exposure to high tides and surf); and 4) the proportion of young, maternally inexperienced females pupping in a particular area. Most motherpup separations were caused directly by 1) adult males moving through the harem; 2) pups wandering from their mothers; 3) female aggression; and 4) inclement weather. Most of the separations, as well as adoptions, occurred when pups were quite young. Mother-pup recognition appeared to be based on a combination of acoustic, visual, and olfactory cues, and most mother-pup reunions were effected by the female rather than her pup. On the main island breeding area, 572 orphans were marked. Of these, five percent relocated their mother, 27 percent were adopted or frequently cared for by foster mothers, and 68 percent were not adopted, or rarely fostered. The survival of an orphan was clearly contingent on the amount of care it received; most orphans which were not nursed or protected by females died before reaching 6 weeks of age. Frequently, an adopted orphan's foster mother was in the stage of lactation which corresponded closely to that of its own mother. The most common fostering event involved females that had lost their own pup and adopted a single orphan. Other pupless females attempted to steal a pup, cared for a pup while it was still with its mother, adopted a weaned pup, adopted two pups, or indiscriminately nursed any orphaned pup that approached. Some females kept their own pup in addition to fostering in alien pup. Most foster mothers were young and had little or no previous maternal experience. The formation of large, high-density breeding rookeries, due to a scarcity of suitable breeding sites, results in frequent mother-pup separations, especially during inclement weather and tidal conditions. Many opportunities for adoptive behavior are therefore presented, because of the great number of orphans and pupless females. Increased maternal experience appears to be a benefit associated with adoption. Some instances of fostering behavior may also be based on “reproductive errors” on the part of the foster mother.

Flow equivalence, hyperbolic systems and a new zeta function for flows

Abstract: We analyze the dynamics of diffeomorphisms in terms of their suspension flows. For many Axion A diffeomorphisms we find simplest representatives in their flow equivalence class and so reduce flow equivalence to conjugacy. The zeta functions of maps in a flow equivalence class are correlated with a zeta function ζH for their suspended flow. This zeta function is defined for any flow with only finitely many closed orbits in each homology class, and is proven rational for Axiom A flows. The flow equivalence of Anosov diffeomorphisms is used to relate the spectrum of the induced map on first homology to the existence of fixed points. For Morse-Smale maps, we extend a result of Asimov on the geometric index.

Isolation, purification, and characterization of mouse placental lactogen

Abstract: Mouse placental lactogen was purified 1840-fold from BALB/c placentae from days 14-18 of gestation with an overall yield of 29%. The purification procedure included alkaline homogenization and extraction, ammonium sulfate precipitation, hydrophobic interaction chromatography on Phenyl-Sepharose, ion-exchange chromatography on CM- and DEAE-cellulose, and gel exclusion chromatography on Sephadex G-100. On 10% alkaline polyacrylamide gels, mouse placental lactogen had an Rf of 0.19. Electrophoresis in gels containing NaDodSO4 showed a single band with a mobility corresponding to a Mr of 23,000 +/- 1000. The isoelectric point, determined by isoelectric focusing in 8 M urea/5% 2-mercaptoethanol, was 7.1. When tested in the pigeon crop sac assay, 10 micrograms of mouse placental lactogen produced stimulation comparable with that evoked by 10 micrograms of ovine prolactin. In the rabbit mammary gland radioreceptor assay, mouse placental lactogen was 150% more potent than ovine prolactin in displacing 125I-labeled ovine prolactin from rabbit mammary gland membranes. Iodinated purified mouse placental lactogen could be displaced from rabbit mammary gland membranes by mouse placental lactogen, mouse prolactin, and ovine prolactin. Ovine prolactin was 45% as avid as mouse placental lactogen is displacing 125I-labeled mouse placental lactogen from rabbit mammary gland membranes. Mouse placental lactogen did not crossreact with antisera to mouse prolactin or mouse growth hormone in a radioimmunoassay.

Is the olivine–spinel phase transformation martensitic?

Abstract: Olivine, the dominant mineral in the Earth's uppermost mantle, undergoes one, or possibly a series of phase transformations to adopt a spinel structure at pressures above ∼13 GPa. The mechanism by which the transformation is accomplished could have important implications for understanding mantle dynamics and deep focus earthquakes. Recently, it has been proposed that the transformation may proceed by a martensitic mechanism1–5. We discuss here the characteristic properties of martensitic transformations and present evidence that the analogous transformation in Mg2GeO4 does not proceed by such a process.

Glyoxysomes in higher plants

Abstract: Glyoxysomes, distinctive organelles containing each of the five enzymes of the glyoxylate cycle, were first isolated from endosperm tissue of germinating castor beans in 1967.' In this plant tissue, there is a massive conversion of stored triglyceride to sucrose, and as shown in FIGURE 1,the glyoxylate cycle, wherein two moles of acetyl-CoA are converted to one mole of succinate, is the central and unusual feature that permits gluconeogenesis.' As originally f~rmulated,~ the glyoxylate cycle was regarded as an adjunct or by-pass of the Krebs tricarboxylic acid cycle. The discovery of the glyoxysome showed that, in the castor bean endosperm, the reactions of the glyoxylate cycle were quite independent of those of the tricarboxylic acid cycle occurring in the mitochondria. Both organelles contain specific isoenzymes of citrate synthetase, aconitase, and malate dehydrogenase. Only the glyoxysomes house the unique enzymes of the glyoxylate cycle, malate synthetase and isocitrate lyase (TABLE 1). and only the mitochondria contain pyruvate dehydrogenase, a-ketoglutarate dehydrogenase, succinate dehydrogenase, fumarase, and the various components of the electron transport sy~tem. '*~.~ The glyoxysomes, which are cleanly separated from mitochondria on linear sucrose gradients, are recovered in 54% sucrose at an equilibrium density of 1.25 g/ml as oblate or spherical structures, -1 pm in diameter. They are surrounded by a single membrane with an amorphous interior! Thus in morphology they resemble the microbodies of mammalian liver, and subsequent examination showed that they in fact contain catalase, urate oxidase, and a-OH acid (glycolate) ~xidase, ' ,~ the typical enzymes of liver peroxisomes, which have been intensively studied by de Duve and his colleague^,^ and showed similar behavior in sucrose gradients. The glyoxysomes account for -20% of the particulate protein in the 10K pellet and are seen in electron micrographs of the parent tissue in numbers roughly equal to those of mitochondria.' A virtually complete recovery of intact mitochondria and glyoxysomes present in homogenates prepared from 4-5-day-old endosperm by chopping with razor blades is achieved by placing the homogenate directly over a sucrose gradient and centrifuging (FIGS. 2 & 3); very little isocitrate lyase (glyoxysomal marker) or fumarase (mitochondria1 marker) is present anywhere in the gradient other than in the respective organelles? It had been anticipated that the first part of the gluconeogenic pathway from fat, the &oxidation of fatty acids, would occur in mitochondria, as it was then known to occur in mitochondria from liver. It came then as a surprise to find that in the mitochondria from the endosperm tissue, there was no @-oxidation activity: these reactions were found exclusively in the glyoxysomes.'o~ll The products of palmitoyl-CoA oxidation in the glyoxysomes were acetyl-CoA and NADH; the first step in the pathway, in which flavin is reduced, was directly linked to

Ricin inhibition of in vitro protein synthesis by plant ribosomes.

Abstract: In vitro translation systems were prepared with supernatant factors from wheat germ and 80S ribosomes from wheat germ, barley embryos, watermelon cotyledons, pea cotyledons, and castor bean endosperm. Ricin A-chain, which strongly inhibits protein synthesis by mammalian ribosomes, inhibited all of the plant ribosomal systems by 50% when present at 25-45 μg/ml—≈23,000 times the concentration needed to inhibit mammalian systems. Ricinus communis agglutinin A-chain, a protein similar to ricin A-chain, inhibited translation by the plant systems 50% at concentrations 5-10 times those of the ricin A-chain. Ribosomes from castor bean endosperm, the source of ricin and the agglutinin, were just as susceptible to the inhibitors as were ribosomes from the other four plants. Compartmentation of the inhibitors within vacuoles derived from protein bodies of the endosperm appears to be responsible for protecting cytoplasmic protein synthesis during germination of castor beans.

The development and characterization of a homologous radioimmunoassay for mouse placental lactogen.

Abstract: A highly specific and sensitive homologous radioimmunoassay (RIA) has been developed for mouse placental lactogen(mPL). Mouse pregnancy serum and placental extracts showed parallel dilution-response curves, and no significant cross-reaction was seen with either mouse growth hormone or mouse prolactin. The sensitivity of the assay ranged from 0.5 to 1.0 ng/ml, and the intra- and inter-assay coefficients of variation were 5 and 11%, respectively. By RIA, mPL levels were detectable on day 9 of pregnancy (1 ng/ml) and increased until day 14 (100-150 ng/ml) in both C3H and BALB/c strains. On days 14-18 of pregnancy, mPL levels were maintained (95-125 ng/ml) in C3H mice, while they continued to increase (greater than 250 ng/ml) in BALB/c mice. In both strains, a midpregnancy peak in prolactin-like activity was detected by a radioreceptor assay but not by the mPL RIA.

On a Class of Integral Operators with Discontinuous Symbol

Abstract: Given finite or infinite intervals I and J we consider the integral operator on L2(I) with kernel $$\frac{\alpha } {{2\pi }}\int {_J } \,e^{i\alpha \xi \left( {x - y} \right)} \sigma \left( {x, \xi } \right)d\xi$$ where σ is a function belonging to the Schwartz space of rapidly decreasing functions on R2. If σ is hermitian matrix-valued then the operator is almost self-adjoint in a sense which will be made precise and we denote its real part by A(σ). The main result of the paper describes the second-order asymptotics as α → ∞ of tr f(A(σ)) where f is a suitable function of a real variable.