Showing papers by "Stony Brook University published in 1977"

Renormalization, vortices, and symmetry-breaking perturbations in the two-dimensional planar model

Abstract: The classical planar Heisenberg model is studied at low temperatures by means of renormalization theory and a series of exact transformations. A numerical study of the Migdal recursion relation suggests that models with short-range isotropic interactions rapidly become equivalent to a simplified model system proposed by Villain. A series of exact transformations then allows us to treat the Villain model analytically at low temperatures. To lowest order in a parameter which becomes exponentially small with decreasing temperature, we reproduce results obtained previously by Kosterlitz. We also examine the effect of symmetry-breaking crystalline fields on the isotropic planar model. A numerical study of the Migdal recursion scheme suggests that these fields (which must occur in real quasi-two-dimensional crystals) are strongly relevant variables, leading to critical behavior distinct from that found for the planar model. However, a more exact low-temperature treatment of the Villain model shows that hexagonal crystalline fields eventually become irrelevant at temperatures below the ${T}_{c}$ of the isotropic model. Isotropic planar critical behavior should be experimentally accessible in this case. Nonuniversal behavior may result if cubic crystalline fields dominate the symmetry breaking. Interesting duality transformations, which aid in the analysis of symmetry-breaking fields are also discussed.

Observation of a Dimuon Resonance at 9.5 GeV in 400-GeV Proton-Nucleus Collisions

Abstract: Dimuon production is studied in 400-GeV proton-nucleus collisions. A strong enhancement is observed at 9.5 GeV mass in a sample of 9000 dimuon events with a mass ${m}_{{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}}g5$ GeV.

The motivation of self-injurious behavior: A review of some hypotheses.

Abstract: The literature on self-injurious behavior suggests five major hypotheses concerning the motivation of such behavior: (a) self-injurious behavior is a learned operant, maintained by positive social reinforcement (positive reinforcement hypothesis); (b) self-injurious behavior is a learned operant, maintained by the termination of an aversive stimulus (negative reinforcement hypothesis) ; (c) self-injurious behavior is a means of providing sensory stimulation (self-stimulation hypothesis); (d) self-injurious behavior is the product of aberrant physiological processes (organic hypothesis); and (e) self-injurious behavior is an attempt to establish ego boundaries or to reduce guilt (psychodynamic hypotheses). Data bearing on each hypothesis are reviewed and evaluated. Effective treatment may depend on a recognition of the different motivational sources of self-injurious behavior and the developmental relationships existing among these sources. Animal analogue experiments may provide clues to the motivation of self-injurious behavior in cases in which human experimentation is ethically indefensible.

Jets from Quantum Chromodynamics

Abstract: The properties of hadronic jets in ${e}^{+}{e}^{\ensuremath{-}}$ annihilation are examined in quantum chromodynamics, without using the assumptions of the parton model. We find that two-jet events dominate the cross section at high energy, and have the experimentally observed angular distribution. Estimates are given for the jet angular radius and its energy dependence. We argue that the detailed results of perturbation theory for production of arbitrary numbers of quarks and gluons can be reinterpreted in quantum chromodynamics as predictions for the production of jets.

A psychophysiological exploration of sexual arousal patterns in females and males.

Abstract: Fifty-nine female and 39 male undergraduates completed 3 sessions of a psychophysiological study on sexual arousal. Subjects were assigned to one of six experimental groups. Subjects within each group were exposed to a series of four audio-tapes, and were asked to fantasize before and after the tape series. Tapes varied in their erotic and romantic content, and two sex role dimensions were also varied across tapes. Dependent measures included scaled subjective reports, genital pulse amplitude and blood volume responses, heart rate, and finger pulse amplitude. Erotic contents were significantly more sexually arousing than nonerotic contents for both sexes. Romantic content did not significantly enhance the facilitation of sexual arousal. Nontraditional sex roles were significantly more arousing for females, with a similar nonsignificant trend for males. There were significant correlations between genital pulse amplitude and subjective reports of arousal; however, for females the genital blood volume measure showed less reliable agreement with subjective report. Genital pulse amplitude was the most reliable and precise indicator of arousal and accounted for the most variance across conditions. No significant changes occurred on the heart rate and finger pulse amplitude measures. Although subjects were able to become aroused by fantasy alone, listening to erotic tapes did not facilitate their ability to be sexually aroused during fantasy.

Simple Model for Characterizing the Electrical Resistivity in A − 15 Superconductors

Abstract: A discussion of some of the difficulties with previous analyses of the resistivity of $A\ensuremath{-}15$ compounds is given. Precise high-temperature data on $\ensuremath{\alpha}$-particle- and electron-damaged ${\mathrm{Nb}}_{3}$Ge and ${\mathrm{Nb}}_{3}$Sn samples with different defect concentrations are presented here and analyzed in a simple way with use of a phenomenological model based on the idea that the ideal resistivity must approach some limiting value in the regime where the mean free path becomes comparable to the interatomic spacing.

Stress in the lithosphere: Inferences from steady state flow of rocks

Abstract: Mechanical data and flow processes from steady state deformation experiments may be used to infer the state of stress in the lithosphere and asthenosphere. Extrapolations of flow equations to a representative geologic strain rate of 10−14/sec. for halite, marble, quartzite, dolomite, dunite and enstatolite are now warranted because the steady state flow processes in the experiments are identical to those in rocks and because the geotherms are reasonably well established. More direct estimates are obtained from free dislocation densities, subgrain sizes and recrystallized grain sizes all of which are functions only of stress. Using the last of these techniques, we have estimated stress profiles as a function of depth from xenoliths in basalts and kimberlites, whose depths of equilibration were determined by pyroxene techniques, from four different areas of subcontinental and suboceanic upper mantle. The results are similar and indicate stress differences of about 200 to 300 bars at 40 to 50 km, decaying to a few tens of bars at depths betow 100 km. These stresses are reasonable and are in accord with extrapolations of the mechanical data provided that allowance is made for a general increase in strain rate and decrease in viscosity with depth.

Supergravity and the S Matrix

Abstract: We discuss supergravity from an $S$-matrix point of view. Kinematical constraints on helicity amplitudes determine the spin-2 and spin-3/2 Born amplitudes almost uniquely, and force Born amplitudes involving spin-5/2 fermions to vanish. Global supersymmetry is then used to determine the Born amplitudes completely. We suggest that Lorentz invariance, presence of only one (dimensional) coupling constant $\ensuremath{\kappa}$, and global supersymmetry lead to a unique locally supergauge-invariant theory of spin-2 and spin-3/2 particles. We draw similar conclusions for a model uniting supergravity and the Wess-Zumino scalar multiplet.

The location of the polio genome protein in viral RNAs and its implication for RNA synthesis.

Abstract: Evidence is presented that a small protein (VPg) is covalently attached to the 5′-terminal oligonucleotide VPg–pU-U–A–A–A–A–C–A–Gp of the polio genome, to nascent strands of the polio replicative intermediate and to poly(U) of minus strands. A model of polio RNA replication is proposed implicating VPg in initiation of RNA synthesis, possibly as primer.

Locomotor behavior and muscular anatomy of sympatric Malaysian leaf-monkeys (Presbytis obscura and Presbytis melalophos).

Abstract: Sympatric Malaysian leaf-monkeys, Presbytis obscura and Presbytis melalophos show quantitative differences in their use of different locomotor patterns during daily activities. P. obscura primarily moves quadrupedally along large boughs; P. melalophos relies more on leaping between smaller supports. P. melalophos also uses forelimb suspension more than does P. obscura. Comparison of the muscular anatomy of the shoulder, arm, trunk, hip and thigh show numerous statistically significant differences between the two species in relative mass of individual muscles and in details of muscular origin and insertion. In almost all instances these differences accord with the types of differences in muscular anatomy predictable from either biomechanical analyses of locomotor behavior or comparative anatomical studies of other mammalian species.

Consistency and variability among college students in rating their teachers and courses: A review and analysis

Abstract: As indicated by the reliability of individual ratings, college students are only moderately consistent in rating their teachers and courses, although these modest interrater associations do produce substantial reliabilities for composite ratings when the ratings of at least 20 to 25 students in a class are averaged together. The patterning and correlates of variability of student ratings within classes are examined. Certain attributes and experiences of students are weakly related to their ratings, and inconsistently so, across studies; others are more strongly and consistently related. Various correlates of student ratings have also been found to interact as well as linearly combine with one another in their association with ratings. Moreover, certain kinds of “fit” between teachers and different students in their classes are related to ratings. Whether various correlates of within-class ratings are to be interpreted as biasing factors or as natural influences on social perception is analyzed in terms of whether students' ratings are objective descriptions or subjective, evaluative reactions.

Frustration and ground-state degeneracy in spin glasses

Abstract: The problem of an Ising model with random nearest-neighbor interactions is reformulated to make manifest Toulouse's recent suggestion that a broken "lattice gauge symmetry" is responsible for the unusual properties of spin glasses. Exact upper and lower bounds on the ground-state energy for models in which the interactions are of constant magnitude but fluctuating sign are obtained, and used to place restrictions on possible geometries of the unsatisfied interactions which must be present in the ground state. Proposed analogies between the ferromagnet---spin-glass phase boundary at zero temperature and a percolation threshold for the "strings" of unsatisfied bonds are reviewed in the light of this analysis. Monte Carlo simulations show that the upper bound resulting from a "one-dimensional approximation" to the spin-glass ground-state energy is reasonably close to the actual result. The transition between spin glass and ferromagnet at 0 K appears to be weakly first order in these models. The entropy of the ground state is obtained from the temperature dependence of the internal energy, and compared with the density of free spins at very low temperatures. For a two-dimensional spin glass in which half the bonds are antiferromagnetic, $S(0)\ensuremath{\approx}0.099{k}_{B}$; for the analogous three-dimensional spin glass the result is $S(0)\ensuremath{\approx}0.062{k}_{B}$. Monte Carlo kinetic simulations are reported which demonstrate the existence and stability of a field-cooled moment in the spin-glass ground state.

Solutions of the Maxwell and Yang-Mills equations associated with hopf fibrings

Abstract: It is shown that the magnetic pole of lowest strength and the pseudoparticle solution of the Yang-Mills equations correspond to natural connections defined on the principal bundlesU(2)/U(1)=S3 →S2 andSp(2)/Sp(1)=S7 →S4, respectively. This observation leads to a general methods of constructing new, topologically nontrivial solutions of the Maxwell and Yang-Mills equations. Among them is an “electromagnetic instanton” defined over the two-dimensional complex projective space endowed with the Fubini-Study metric.

Small-scale structure of spacetime as the origin of the gravitational constant

Abstract: We suggest a means of incorporating the Planck length as a fundamental constant determined by the structure of spacetime. In this scheme the spacetime symmetry group is taken as the de Sitter group with radius of curvature proportional to the Planck length, but we argue that the effects of this curvature are not apparent at elementary-particle length scales. To make the connection with gravity we present a formulation of the gravitational interaction as the gauge theory of the de Sitter group. We obtain an action containing the Einstein-Cartan action, but in which the dimensional gravitational constant $G$ appears naturally as the consequence of the commutation relation of the de Sitter group. We also find a cosmological term, higherderivative couplings of the gravitational field, and a propagating torsion field, which we discuss.

Solution of the Yukawa closure of the Ornstein-Zernike equation

Abstract: The solution of the Ornstein-Zernike equation with Yukawa closure [c(r)=\(\sum\limits_i {K_i e^{ - z_i (r - 1)} /r} \) forr>1] is generalized for an arbitrary number of Yukawas, using the Fourier transform technique introduced by Baxter. Full equivalence to the results of Waisman, Hoye, and Stell is proved for the case of a single Yukawa. Finally, a convenient form of the Laplace transform ofg(s) is found, which can be easily inverted to give a stepwise, rapidly converging series forg(r).

Cosmological constant in supergravity

Abstract: We construct an extension of pure supergravity which contains a cosmological term and a masslike term for the spin-$\frac{3}{2}$ field. Unlike another recent model which incorporates these features, that presented here is constructed from the usual spin-2, spin-$\frac{3}{2}$ fields alone.

Microdolomite inclusions in cloudy prismatic calcites; a proposed criterion for former high-magnesium calcites

Abstract: Inclusions in synsedimentary prismatic calcites of the Mississippi Lake Valley Formation bioherms, New Mexico, are 1-10-micron subhedral to euhedral "microdolomites" which occur in crystallographic continuity with the host calcites. These microdolomite inclusions occur exclusively in echinoderm grains, in the cloudy prismatic calcites, and in rare cloudy syntaxial overgrowths on echinoderms; they do not occur in adjacent mud nor in other skeletal grains. Cathodoluminescence of the cloudy dolomite-rich prismatic calcites reveals a nonluminescing, radial fibrous component, and an interfiber luminescing calcite. The radial fibrous mosaic, whose fibers are length slow, reflects the fabric of the cement precursor to the cloudy radiaxial prismatic calcites; whereas the luminescing calcite i interpreted as younger syntaxial interfiber pore filling. The microdolomite inclusions are restricted dominantly to the nonluminescing portions. This restricted distribution of the microdolomite inclusions argues for an autochthonous source for the Mg on a scale of single grains or crystals, and thus indicates a high-Mg calcite precursor to the cloudy calcites. Infilling of the interfiber pores of the radial fibrous mosaic with the luminescent, low-Mg calcite effectively isolated the metastable high-Mg calcites from conventional diagenetic stabilization. The Mg was redistributed within individual grains and fibers into microdolomite inclusions and low-Mg calcites by either an incongruent-dissolution or solid-state exsolution process. The presence of the microdolomite inclusions in cloudy calcites is prime evidence for a high-Mg calcite precursor, and, therefore, for a marine precipitational environment. We suggest this criterion is widely applicable to coarse prismatic fabrics throughout the geologic column, and is of particular importance considering that crystal fabric alone is generally inadequate in distinguishing coarse prismatic cements precipitated in marine waters from those precipitated in fresh meteoric waters.

The revised 56-item CRPBI as a research instrument: Reliability and factor structure.

Abstract: The utility of the revised 56-item Child's Report of Parental Behavior Inventory (CRPBI), an instrument less cumbersome than the 260-item original, was examined. Study I found the instrument to be highly reliable at 1-week and 5-week retest intervals. Study II found the factor structure of the revision similar to that of the original, with Factor III somewhat less stable than the other two factors. It was concluded that, in general, the 56-item CRPBI appeared to stand up well as a research instrument.

Language, praxis, and the right hemisphere Clues to some mechanisms of consciousness

Abstract: The linguistic capacity of each separate cerebral hemisphere was examined in a 15-year-old, callosally sectioned, normally right-handed male. The results demonstrated that while the right hemisphere was not capable of expressive speech, it could comprehend nouns and verbs, and also possessed the motor engrams necessary to carry out verbal and pictorial commands. In addition, the mute hemisphere was found to be capable of spelling the names of visually presented items by arranging letters as well as by writing with the left hand. Finally, the manner in which the left hemisphere dealt with the overt bodily response to commands presented to the right hemisphere suggested clues to what we feel are mechanisms by which a personal sense of conscious reality is created in the normal brain.

Frequencies and patterns of bone marrow involvement in non‐hodgkin lymphomas: Observations on the value of bilateral biopsies

Abstract: Pretreatment bone marrow biopsies and aspirations from 85 consecutive patients with non-Hodgkin lymphoma were reviewed All patients had at least one adequate biopsy Criteria for involvement with lymphoma were clearly defined The frequencies and morphologic patterns of involvement correlated with the lymph node diagnoses assigned according to Rappaport's classification Diffuse, well-differentiated lymphocytic and diffuse mixed lymphocytic-histiocytic lymphoma were most frequently involved (100%), followed by diffuse, poorly differentiated lymphocytic (56%), nodular, poorly differentiated lymphocytic (39%), diffuse undifferentiated (33%), diffuse histiocytic (25%), and nodular mixed lymphocytic-histiocytic lymphoma (23%) Each of the histologic subtypes tended to have an identifiable pattern of bone marrow involvement Most striking was a predominance of paratrabecular localization of lymphoma in patients with nodular, poorly differentiated lymphocytic lymphoma Biopsies were superior to both clot sections and aspirate smears in making the diagnosis of lymphoma in all subtypes, but discrepancies were more common in the nodular than in the diffuse lymphomas A total of 52 pretreatment bilateral bone marrow biopsies from patients with non-Hodgkin lymphoma were reviewed for concordance of diagnoses In five patients, one biopsy was positive for lymphoma while the other was negative Four of the five patients had histiocytic lymphoma, and the other had nodular mixed lymphoma In two of these patients the bone marrow examination obviated the need for more invasive procedures to establish stage IV disease We concluded that bone marrow biopsies are necessary for staging non-Hodgkin lymphomas and that bilateral biopsies are most useful in the histiocytic subclass