Showing papers by "Cornell University published in 1980"

Toward a positive theory of consumer choice

Abstract: The economic theory of the consumer is a combination of positive and normative theories. Since it is based on a rational maximizing model it describes how consumers should choose, but it is alleged to also describe how they do choose. This paper argues that in certain well-defined situations many consumers act in a manner that is inconsistent with economic theory. In these situations economic theory will make systematic errors in predicting behavior. Kanneman and Tversey's prospect theory is proposed as the basis for an alternative descriptive theory. Topics discussed are: undeweighting of opportunity costs, failure to ignore sunk costs, scarch behavior choosing not to choose and regret, and precommitment and self-control.

Detrended correspondence analysis: an improved ordination technique

Abstract: Studies by ourselves and others (Swan 1970, Austin & Noy-Meir 1972, Beals 1973, Hill 1973, 1974, Austin 1976a, b, Fasham 1977, Gauch Whittaker & Wentwarth 1977, Noy-Meir & Whittaker 1977, Orloci 1978, Gauch, Whittaker & Singer 1979) have found faults with all ordination techniques currently in use, at least when applied to ecological data specifying the occurrences of species in community samples. These faults certainly do not make existing techniques useless; but they mean that results must be interpreted with caution. Even with the best techniques, the underlying structure of the data is often poorly expressed.

Exclusive Processes in Perturbative Quantum Chromodynamics

Abstract: We present a systematic analysis in perturbative quantum chromodynamics (QCD) of large-momentum-transfer exclusive processes. Predictions are given for the scaling behavior, angular dependence, helicity structure, and normalization of elastic and inelastic form factors and large-angle exclusive scattering amplitudes for hadrons and photons. We prove that these reactions are dominated by quark and gluon subprocesses at short distances, and thus that the dimensional-counting rules for the power-law falloff of these amplitudes with momentum transfer are rigorous predictions of QCD, modulo calculable logarithmic corrections from the behavior of the hadronic wave functions at short distances. These anomalous-dimension corrections are determined by evolution equations for process-independent meson and baryon "distribution amplitudes" $\ensuremath{\varphi}({x}_{i}, Q)$ which control the valence-quark distributions in high-momentum-transfer exclusive reactions. The analysis can be carried out systematically in powers of ${\ensuremath{\alpha}}_{s}({Q}^{2})$, the QCD running coupling constant. Although the calculations are most conveniently carried out using light-cone perturbation theory and the light-cone gauge, we also present a gauge-independent analysis and relate the distribution amplitude to a gauge-invariant Bethe-Salpeter amplitude.

Investigation of chromium, cerium and cobalt as markers in digesta. Rate of passage studies

Abstract: A new liquid marker, cobalt-ethylenediamine tetraacetic acid (EDTA), and two solid markers, chromium (Cr) and cerium (Ce) mordanted plant cell walls, were investigated. Synthesis and methods of analysis are described for the markers. The Cr- and Ce-cell wall complexes were tested for stability to EDTA, hydrochloric acid and rumen microorganisms. Plant cell walls were rendered indigestible by mordanting with Cr and 98% of the marker remained on the fibre after a simulated sequence (in vitro) of digestion. Ce-mordanted cell walls were 35% digestible in vitro using a rumen culture, and 56% of the marker could be washed off the remaining fibre. Treatment with EDTA removed all Ce and 15% of the Cr. Hydrochloric acid (0.01M) had a negligible effect on the removal of Cr from the cell walls, whereas 0.1M acid removed, on average, 10% of the marker. Losses of Cr from the mordant may be related to the quality of the preparation. Co-EDTA was found to be comparable to Cr-EDTA. The urinary excretion of Cr and Co was 2–3% in most animals except in rabbits, which excreted as much as 30% of the liquid markers in the urine.

Population Marginal Means in the Linear Model: An Alternative to Least Squares Means

Abstract: The parameter concept in the term least squares mean is defined and given the more meaningful name population marginal mean; and its estimation is discussed.

Charmonium: Comparison with Experiment

Abstract: The charmonium model, formulated in detail in an earlier publication, is compared in a comprehensive fashion with the data on the $\ensuremath{\psi}$ family. The parameters of the "naive" model, in which the system is described as a $c\overline{c}$ pair, are determined from the observed positions of $\ensuremath{\psi}$, ${\ensuremath{\psi}}^{\ensuremath{'}}$, and the $P$ states. The model then yields a successful description of the spectrum of spin-triplet states above the charm threshold. It also accounts for the ratio of the leptonic widths of ${\ensuremath{\psi}}^{\ensuremath{'}}$ and $\ensuremath{\psi}$. When the $c\overline{c}$ potential is applied to the $\ensuremath{\Upsilon}$ family, it accounts, without any readjustment of parameters, for the positions of the $2S$ and $3S$ levels and for the leptonic widths of $\ensuremath{\Upsilon}$ and ${\ensuremath{\Upsilon}}^{\ensuremath{'}}$ relative to that of $\ensuremath{\psi}$. The model does not give acceptable values of the absolute leptonic widths, a shortcoming which is ascribed to large quantum-chromodynamic corrections to the van Royen-Weisskopf formula. The calculated $E1$ rates are about twice the values observed in the $\ensuremath{\psi}$ family. This naive model is also extended with considerable success to mesons composed of one heavy and one light quark. A significant extension of the model is achieved by incorporating coupling to charmed-meson decay channels. This gives a satisfactory understanding of $\ensuremath{\psi}(3772)$ as the $1^{3}D_{1}$ $c\overline{c}$ state, mixed via open and closed decay channels to $2^{3}S$. The model has decay amplitudes that are oscillatory functions of the decay momentum; these oscillations are a direct consequence of the radial nodes in the $c\overline{c}$ parent states. These amplitudes provide a qualitative understanding of the observed peculiar branching ratios into various charmed-meson channels near the resonance at 4.03 GeV, which is assigned to $3^{3}S$. The coupling of the $c\overline{c}$ states below the charm threshold to closed decay channels modifies the bound states and leads to reduction of about 20% in $E1$ rates in comparison to those of the naive model.

Renormalization-group approach to the Anderson model of dilute magnetic alloys. I. Static properties for the symmetric case

Abstract: The temperature-dependent impurity susceptibility for the symmetric Anderson model is calculated for all physically relevant values of its parameters $U$ (the Coulomb correlation energy) and $\ensuremath{\Gamma}$ (the impurity-level width). It is shown that, when $Ug\ensuremath{\pi}\ensuremath{\Gamma}$, for temperatures $Tl\frac{U}{(10{k}_{B})}$ the symmetric Anderson model exhibits a local moment and that its susceptibility maps neatly onto that of the spin-\textonehalf{} Kondo model with an effective coupling given by $\ensuremath{\rho}{J}_{\mathrm{eff}}=\ensuremath{-}\frac{8\ensuremath{\Gamma}}{\ensuremath{\pi}U}$. Furthermore, this mapping is shown for remarkably large values of $|\ensuremath{\rho}{J}_{\mathrm{eff}}|$. At very low temperatures (much smaller than the Kondo temperature) the local moment is frozen out, just as for the Kondo model, leading to a strong-coupling regime of constant susceptibility at zero termperature. The results also depict the formation of a local moment from the free orbital as $T$ drops below $U$, a feature not present in the Kondo model. Finally, when $U\ensuremath{\ll}\ensuremath{\pi}\ensuremath{\Gamma}$ there is a direct transition from free-orbital regime for $T\ensuremath{\gg}\ensuremath{\Gamma}$ to the strong-coupling regime for $T\ensuremath{\ll}\ensuremath{\Gamma}$. The calculations were performed using the numerical renormalization group originally developed by Wilson for the Kondo problem. In addition to the actual numerical calculations, analytic results are presented. In particular, the effective Hamiltonians, i.e., fixed-point Hamiltonian plus relevant and marginal operators, are constructed for the free-orbital, local-moment, and strong-coupling regimes. Analytic formulas for the impurity susceptibility and free energy in all three regimes are developed. The impurity specfic heat in the strong-coupling regime is calculated.

Effect of aluminium speciation on fish in dilute acidified waters

Abstract: Acidification of lakes and streams is a serious water quality problem in high elevation granitic ecosystems in the northeastern US1–3. An important consequence of acidification is the mobilisation of aluminium from the edaphic to the aquatic environment3–5. Elevated levels of aluminium may have serious ramifications for biological communities, particularly fish, inhabiting acidified aquatic systems5,6. In this study, water quality data were collected from several acidified lakes and streams in the Adirondack region of New York state. The purpose of this investigation was to characterise aluminium chemistry in these acidified waters and to assess the relative toxicity of soluble aluminium species to fish. Aqueous aluminium speciation was found to be highly variable in Adirondack waters, and its effect on fish was also variable.

The critical probability of bond percolation on the square lattice equals 1/2

Abstract: We prove the statement in the title of the paper.

Causality and Properties

Abstract: It is events, rather then objects or properties, that are usually taken by philosophers to be the terms of the causal relationship. But an event typically consists of a change in the properties or relationships of one or more objects, the latter being what Jaegwon Kim has called the “constituent objects” of the event.1 And when one event causes another, this will be in part because of the properties possessed by their constituent objects. Suppose, for example, that a man takes a pill and, as a result, breaks out into a rash. Here the cause and effect are, respectively, the taking of the pill and the breaking out into a rash. Why did the first event cause the second? Well, the pill was penicillin, and the man was allergic to penicillin. No doubt one could want to know more — for example, about the biochemistry of allergies in general and this one in particular. But there is a good sense in which what has been said already explains why the one event caused the other. Here the pill and the man are the constituent objects of the cause event, and the man is the constituent object of the effect event. Following Kim we can also speak of events as having “constituent properties” and “constituent times”. In this case the constituent property of the cause event is the relation expressed by the verb ‘takes’, while the constituent property of the effect event is expressed by the predicate ‘breaks out into a rash’. The constituent times of the events are their times of occurrence. Specifying the constituent objects and properties of the cause and effect will tell us what these events consisted in, and together with a specification of their constituent times will serve to identify them; but it will not, typically, explain why the one brought about the other. We explain this by mentioning certain properties of their constituent objects. Given that the pill was penicillin, and that the man was allergic to penicillin, the taking of the pill by the man was certain, or at any rate very likely, to result in an allergic response like a rash. To take another example, suppose a branch is blown against a window and breaks it. Here the constituent objects include the branch and the window, and the causal relationship holds because of, among other things, the massiveness of the one and the fragility of the other.

Report of the IAU/IAG/COSPAR working group on cartographic coordinates and rotational elements of the planets and satellites: 1991

Abstract: Every three years the IAU/IAG Working Group on cartographic coordinates and rotational elements of the planets and satellites revises tables giving the directions of the north poles of rotation and the prime meridians of the planets, satellites, and asteroids. Also presented are revised tables giving their sizes and shapes. Changes since the previous report are summarized in the Appendix.

A finite-element/finite-difference simulation of the injection-molding filling process

Abstract: A detailed formulation is presented for simulating the injection-molding filling of thin cavities of arbitrary planar geometry. The modelling is in terms of generalized Hele-Shaw flow for an inelastic, non-Newtonian fluid under non-isothermal conditions. A hybrid numerical scheme is employed in which the planar coordinates are described in terms of finite elements and the gapwise and time derivatives are expressed in terms of finite differences. The simulation is applied to the filling of a two-gated plate mold having an intentionally unbalanced runner system. Good agreement is obtained with experimental results in terms of short-shot sequences, weldline formation and pressure traces at prescribed points in the cavity.

Evidence for L-glutamate as the neurotransmitter of baroreceptor afferent nerve fibers.

Abstract: Microinjection of L-glutamate into the intermediate nucleus tractus solitarii in anesthetized rats elicits hypotension, bradycardia, and apnea, simulating baroreceptor reflexes. Ablation of the nodose ganglion results in selective reduction of high-affinity uptake of L-glutanate in the nucleus tractus solitarii. L-Glutamate may be the neurotransmitter of afferent nerve fibers from arterial baroreceptors.

Infinitely Many Commensurate Phases in a Simple Ising Model

Abstract: On the basis of systematic low-temperature expansions "to all orders", it is shown that an infinite sequence of spatially modulated commensurate phases, with wave vectors $\frac{\ensuremath{\pi}j}{(2j+1)a}$ ($j=0, 1, 2, \dots{}$), occurs in simple, anisotropic Ising models with nn couplings ${J}_{0}$, ${J}_{1}g0$, in between spin-\textonehalf{} layers, and competing nnn interlayer couplings ${J}_{2}=\ensuremath{-}k{J}_{1}$ along one axis. The free energies, interfacial tensions, and phase boundaries are found for low $T$ in $dg2$ dimensions.

Thin-skinned tectonics in the crystalline southern Appalachians; COCORP seismic-reflection profiling of the Blue Ridge and Piedmont

Abstract: COCORP seismic-reflection profiling in Georgia, North Carolina, and Tennessee and related geological data indicate that the crystalline Precambrian and Paleozoic rocks of the Blue Ridge, Inner Piedmont, Charlotte belt, and Carolina slate belt constitute an allochthonous sheet, generally 6 to 15 km thick, which overlies relatively flat-lying autochthonous lower Paleozoic sedimentary rocks, 1 to 5 km thick, of the proto-Atlantic continental margin. Thus, the crystalline rocks of the southern Appalachians appear to have been thrust at least 260 km to the west, and they overlie sedimentary rocks that cover an extensive area of the central and southern Appalachians. The hydrocarbon potential of these sedimentary rocks is unknown and untested. The data show that the Brevard fault is the surface expression of an eastward-dipping splay off the main sole thrust, and they show, or imply, that other major faults of this region have similar origins. The data support the view that large-scale, thin crystalline thrust sheets may be significant features of orogenic zones.

Dimension of Strange Attractors

Abstract: A relationship between the Lyapunov numbers of a map with a strange attractor and the dimension of the strange attractor has recently been conjectured. Here, the conjecture is numerically tested with use of several different maps, one of which results from a system of ordinary differential equations occurring in plasma physics. For the cases tested, the conjecture is verified to within the obtained accuracy.

Unequal crossing over in the ribosomal DNA of Saccharomyces cerevisiae

Abstract: Unequal sister chromatid exchanges occur at the ribosomal DNA locus of yeast during mitotic growth. The frequency of unequal crossing over, as measured by the deletion or duplication of an inserted genetic marker (LEU2), is sufficient to maintain the sequence homogeneity of the rDNA repeat units.

Dynamics of superfluid films

Abstract: A theory of the dynamical properties of a helium film near its superfluid transition is presented. Details are given of previously published results on the linear response of the film to a substrate oscillation. A key role is played by the diffusive motion of quantized vortices, which become free above the thermodynamic Kosterlitz-Thouless temperature ${T}_{c}$ but which only exist as bound pairs below ${T}_{c}$. An analogy with a two-dimensional plasma is presented and used. Contact is made with experiments involving oscillating substrates. The nucleation of single vortices from pairs is calculated, and this process is balanced against pair recombination to calculate the rate of decay of superflow below ${T}_{c}$. Formulas are worked out for the propagation and damping of third sound, and a discussion is given of hydrodynamic modes. An analogy between the dynamical equations for the film and Maxwell's equations is exploited.

Intertwining Operators for Semisimple Groups, II

Abstract: The purpose of the present paper is to expand the use of intertwining operators for semisimple Lie groups. In an earlier form (see [20]), these operators were meromorphic continuations of integral operators and exhibited equivalences among nonunitary principal series representations, those induced from a minimal parabolic subgroup. We demonstrated that there was an intimate connection between these operators and the irreducibility of the principal series, on the one hand, and the unitarity of the analytically continued representations (the complementary series), on the other hand. In the intervening years we have generalized the setting for intertwining operators significantly, and we have learned of new applications. For the most part, the expansion in the setting is that minimal parabolic subgroups have now been replaced by arbitrary parabolic subgroups M A N , and the representations that are studied are induced from a representation of M A N that is irreducible unitary on M, is one-dimensional on A, and is trivial on N. The expanded theory allows us to determine the degree of reducibility of all series of representations appearing in the Plancherel formula of the group, and to study complementary series attached to them. Such intertwining operators have also now found major applications in classifying representations (see Langlands [29] and Knapp-Zuckerman [-25]) and appear to have significance for some problems in number theory. Our objective in this paper is threefold: to develop the analytic properties of intertwining operators in what seems to be the appropriate degree of generality, to give a dimension formula for the commuting algebras of the unitary representations induced when the representation of M is in the discrete series and the character of A is unitary (and to give some further insights into these representations), and to illustrate a technique for dealing with complementary series. To make it possible to be more specific, we introduce some notation. Let G be a reductive group whose identity component has compact center; the precise axioms for G are given in w 1. Fix a Cartan involution 0 for G, and let P be a parabolic subgroup of G. Then P c~ OP decomposes into the product of commuting subgroups M and A, where A is a vector group and M satisfies the

Structural and floristic diversity of shrublands and woodlands in Northern Israel and other Mediterranean areas

Abstract: Between 1974 and 1978 structure and diversity of shrublands and woodlands of northern Israel were studied along climatic and human-disturbance gradients using 0.1 ha vegetation samples. Diversity increased along the moisture gradient, with highest woody and herb species richness in open Pistacia shrubland on the xeric border of the Mediterranean region, and highest equitability and lowest dominance concentration in sub-humid, moderately grazed, open oak woodlands. Semi-open disturbed shrublands were rich in herbs and had much higher structural, plant species, and animal species diversities than the closed, mature, ‘climax’ maquis. Diversity showed a two-slope response to grazing with highest species numbers in heavily (but not the most severely) grazed woodlands and shrublands. These communities have some of the highest plant alpha diversities in the world; the richness of their floras (especially in annual plants) is the product of relatively rapid evolution under stress by drought, fire, grazing, and cutting. Comparative data on diversity and growth-form composition are compiled for mediterranean communities: Israeli' shrublands and woodlands, California chaparral and woodlands, Chilean matorral, South African fynbos, and Australian heath and mallee. Communities of three of these areas are of more recent (primarily Pleistocene) development and share some similarities; these threc form a sequence (California, Chile, and Old World Mediter-ranean) of increasing length of human disturbance and consequent species diversity. The southwest Australian heath or kwongan and the South African fynbos are, in contrast, derived from ancient Gondwanan heath like communities and are adapted to very old, nutrient-poor soils. The Gondwanan communities are quite different in growth-form structure and soil and nutrient relationships from communities of the three more recent mediterranean areas; the Gondwanan communities are almost lacking in annual species and are exceedingly rich in woody species. The richest temperate plant communities known — grazed Mediterranean pastures vs. fynbos and Australian heath — are in almost polar contrast in their growth-form structures and the bases of their species diversities. This study, sponsored by the U.S.-Israel Binational Science Foundation (No. 450), was carried out by Z. Naveh as principal investigator with R.H. Whittaker as American collaborator. We thank Mr. A. Mann, S. Burmil, Mrs. Chaim, and Mrs. A. Kleen for botanical field work and statistical computations, Mr. D. Feigin and S. Ben Ezrah for technical assistance, Mr. S. Asherow for identification of young plants, and the Nature Reserve Authorities, the Neve Yaar Experimental Station, the Agricultural School Kfar Hanoar Hadati, and Kibbutzim Allonim and Allone Abba for allowing us to use their land for this study. The work by R.H. Whittaker was supported by the U.S. National Science Foundation, Australian National University, and Canberra Botanic Gardens; and we thank all the collaborators in this work.