Showing papers by "Stony Brook University published in 1968"

Phase and Angle Variables in Quantum Mechanics

Abstract: The quantum-mechanical description of phase and angle variables is reviewed, with emphasis on the proper mathematical description of these coordinates. The relations among the operators and state vectors under consideration are clarified in the context of the Heisenberg uncertainty relations. The familiar case of the azimuthal angle variable $\ensuremath{\phi}$ and its "conjugate" angular momentum ${L}_{z}$ is discussed. Various pitfalls associated with the periodicity problem are avoided by employing periodic variables ($sin\ensuremath{\phi}$ and $cos\ensuremath{\phi}$ to describe the phase variable. Well-defined uncertainty relations are derived and discussed. A detailed analysis of the three-dimensional harmonic oscillator excited in coherent states is given. A detailed analysis of the simple harmonic oscillator is given. The usual assumption that a (Hermitian) phase operator $\ensuremath{\varphi}$ (conjugate to the number operator $N$) exists is shown to be erroneous. However, cosine and sine operators $C$ and $S$ exist and are the appr\'opriate phase variables. A Poisson bracket argument using action-angle (rather $J$, $cos\ensuremath{\varphi}$, $sin\ensuremath{\varphi}$) variables is used to deduce $C$ and $S$. The spectra and eigenfunctions of these operators are investigated, along with the important "phase-difference" periodic variables. The properties of the oscillator variables in the various types of states are analyzed with special attention to the uncertainty relations and the transition to the classical limit. The utility of coherent states as a basis for the description of the evolution of the density matrix is emphasized. In this basis it is easy to identify the classical Liouville equation in action-angle variables along with quantum-mechanical "corrections." Mention is made of possible physical applications to superfluid systems.

Systematic desensitization as a counter-conditioning process.

Abstract: Systematic desensitization, demonstrated in both clinical and experimental studies to reduce avoidance behavior, entails the contiguous pairing of aversive imaginal stimuli with anxiety-competing relaxation. If, as is widely assumed, the efficacy of the procedure derives from a genuine counterconditioning process, a disruption of the pairing between graded aversive stimuli and relaxation should render the technique ineffective in modifying avoidance behavior. This hypothesis was strongly confirmed: significant reduction in avoidance behavior was observed only in densensitizat ion Ss, with none occurring either in yoked Ss for whom relaxation was paired with irrelevant stimuli or in yoked Ss who were gradually exposed to the imaginal aversive stimuli without relaxation. Other theoretical issues were raised, especially the problem of transfer from imaginal to actual stimulus situations. Recent years have witnessed increasing application of the systematic desensitization procedure, as developed by Wolpe (1958), to the modification of a wide range of neurotic disorders. In this therapeutic method the client is deeply relaxed and then instructed to imagine scenes from a hierarchy of anxietyprovoking stimuli. Initially he is asked to imagine the weakest item in the list and, if relaxation is unimpaired, is gradually presented incremental degrees of aversive stimuli until eventually he is completely desensitized to the most upsetting scene in the anxiety hierarchy.

Theory of a Two-Dimensional Ising Model with Random Impurities. I. Thermodynamics

Abstract: Recent experiments demonstrate that at the Curie temperature the specific heat may be a smooth function of the temperature. We propose that this effect can be due to random impurities and substantiate our proposal by a study of an Ising model containing such impurities. We modify the usual rectangular lattice by allowing each row of vertical bonds to vary randomly from row to row with a prescribed probability function. In the case that this probability is a particular distribution with a narrow width, we find that the logarithmic singularity of Onsager's lattice is smoothed out into a function which at ${T}_{c}$ is infinitely differentiable but not analytic. This function is expressible in terms of an integral involving Bessel functions and is computed numerically.

How to Make a Token System Fail

Abstract: A token system was instituted in an adjustment class of six third and fourth graders. The aim of the study was to examine aspects of token systems critical in making them effective. The results ind...

Coral Community on Muddy Sand

Abstract: Heteropsammia michelinii, a free-living and free-moving scleractinian coral found in the Australian Great Barrier Reef, has a symbiotic association with a sipunculid worm, Aspidosiphon corallicola. The worm lives in a cavity on the under surface of the coral and it pulls the coral over the muddy surface of the sand.

Role of assessment in behavior modification.

Abstract: The recent introduction of a broad range of behavior modification techniques has brought into focus several questions and issues of concern to clinicians and researchers. The particular problem dis...

Bone Carbonate and the Ca to P Molar Ratio

Abstract: IT is customary to consider the bone salt either as hydroxy-apatite or as tribasic calcium phosphate, principally on the basis of stoichiometric and X-ray diffraction studies1. Nonetheless, the observed molar ratio of Ca/P in the bone salt in most vertebrates is quite variable, and is usually in excess of 1.67, which is the ratio one would expect for hydroxyapatite2–4. Few studies deal directly with this discrepancy, and its dependence on the calcium carbonate content of bone has not been clearly demonstrated.

Effect of adrenergic drugs on the lantern of the larval Photuris firefly.

Abstract: 1. A number of adrenergic drugs were tested for their ability to induce luminescence in the extirpated lantern of the firefly larva. The drugs produce sigmoid doseresponse curves characteristic of drug-receptor interactions when drug concentration is plotted against either maximum intensity or maximum rate of intensity rise. 2. Amphetamine and saline of high potassium concentration induce intense luminescence in freshly extirpated lanterns but act only weakly or not at all in lanterns suffering from treatment by reserpine injection 48 hr. previously. 3. No significant difference in response to norepinephrine was observed in lanterns immersed in standard saline, 0.32 M sucrose, 0.16 M choline chloride or 0.16 M-NaCl2 but 0.107 M-CaCl2 considerably slowed the response. 4. Some generalizations concerning structural character and effectiveness in inducing luminescence were made by comparing the drugs tested. It was not possible to describe the mode of action of the drugs. The observation, however, that solutions lacking sodium and potassium did not significantly alter the response was felt to argue against the action of the adrenergic drugs in affecting ion movement across the photocyte membrane.

Effect of drugs on luminescence in larval fireflies

Abstract: 1. Synephrine and other related monophenolic drugs were tested for potency of luminescence induction in the extirpated lantern of larval fireflies. Synephrine was found to be the most potent drug so far tested, with a threshold concentration of 10 -6 M. 2. Immersion of glowing lanterns in a solution containing 10 -3 M synephrine and 10 -3 M-KCN resulted in rapid extinction of luminescence. Luminescence extinction times in KCN were found to be proportional to synephrine concentration and suggest that only a small ATP pool exists in the lantern. It is hypothesized that synephrine must stimulate ATP production in order to maintain high luminescence intensities. 3. The vertebrate adrenergic blocking agent, dichloroisoproterenol (D.C.I.), was found to slowly induce luminescence which eventually declined to extinction. Synephrine was ineffective in luminescence induction after the declining phase of D.C.I, action began. A close analogue of D.C.I., isoproterenol, acted in a weak but similar manner to synephrine. It is suggested that D.C.I, prevents synephrine action by blocking the photocyte receptor sites.

DNA biosynthesis by isolated mitochondria: a replicative rather than a repair process.

Abstract: The previously observed incorporation of deoxynucleoside triphosphate precursors into DNA by isolated rat liver mitochondria could reflect either replication of DNA or a repair process. Density labeling experiments in cesium chloride demonstrate that DNA synthesized in the presence of 5-bromodeoxyuridine triphosphate instead of thymidine triphosphate shows an appreciable increase in density. In some of the molecules undergoing synthesis, the amount of the density increase indicated a replacement of thymine by bromouracil to the extent of 33 percent. This extensive replacement, which would compute to twice this amount if only a single strand of the duplex is labeled, provides evidence for the synthesis of fairly long pieces of DNA. Such synthesis is characteristic of replication rather than repair, and the results thus suggest that mitochondria are able to replicate their own DNA.

New Geomagnetic Limit on the Mass of the Photon

Abstract: On the basis of recent precise data on the earth's magnetic field, a new upper bound on the mass of the photon is obtained using a method that was originally proposed by Schr\"odinger. The limit is 1.15 \ifmmode\times\else\texttimes\fi{} ${10}^{\ensuremath{-}10}$ ${\mathrm{cm}}^{\ensuremath{-}1}$\ensuremath{\equiv}2.3 \ifmmode\times\else\texttimes\fi{} ${10}^{\ensuremath{-}15}$ eV\ensuremath{\equiv}4.0 \ifmmode\times\else\texttimes\fi{} ${10}^{\ensuremath{-}48}$ g, which is four orders of magnitude better than the best laboratory measurement, that of Plimpton and Lawton.

Survey of biomedical materials and some relevant problems

Abstract: Interest in implanted materials has grown immensely as a direct consequence of several remarkable developments in surgery and biomedical engineering. These include heart-lung machines, artificial kidneys, cardiac pacemakers, arterial and heart valve prosthesis. Perhaps the most dramatic development is that of artificial implanted hearts and various types of cardiac booster pumps. In the way of historical perspective, it is well to recall that many of these developments have tenuous origins in the beginning of this century and in some instances even earlier. Thus, the heart-lung machines are an outgrowth of the organ perfusion equipment developed by Frey and Gruber in 1885, Jacoby in 1890, as well as many others. However, the first clinical application occurred about 1955, an achievement that was the result of extensive post-World War I1 research by many workers. An excellent account is given by Gelleti and Brecker.l Similarly, the first artificial kidneys were investigated by Abel, Roundtree, and Turner in 1913, and the first clinically useful machine was introduced by Kolf about 1944. Current devices, however, are also a consequence of the efforts of many investigators since World War 11. If one asks why these developments were delayed, perhaps two main reasons can be given: the problems arising from blood clotting, and the lack of suitable construction materials. As is well known, the first problem has been solved by means of heparin and other anticoagulants while the availability of physiologically relatively inert materials such as teflon, silicones, dacron, and metals like the 3 16 series stainless steels and Vitallium, have alleviated the second difficulty. Thus, Carrel's crude paraffin-coated aluminum and glass tubes, used as blood vessel replacements in 1912, have been successively replaced by polymethyl methacrylate hollow tubes by Hufnagel in 1947, Vinyon-N plastic fabric tubes by Voorhees in 1952, and finally the knitted dacron arterial prosthesis presently used. In what follows, two important problems associated with implanted materials will be briefly discussed: the deterioration of the implant in the body, and the effect of the implant surface on blood coagulation.

Women's work participation and fertility in metropolitan areas

Abstract: This report examines the hypothesis that a high rate of participation of women in the labor force tends to reduce birth rates in a community. Among metropolitan areas in eight countries about 1950 the proportion of women working was negatively correlated with the child-woman ratio. This relationship held even when the percentage of women married was controlled by partial correlation. Among metropolitan areas of the United States in 1960, women's work participation was negatively associated with various measures of fertility. This was true for eight categories of women grouped by color and age. Further, communities wit?' high levels of female employment tended to have both low proportions of married women and low marital fertility. On the whole, the correlations for nonwhites were lower than those for whites and fell into a somewhat different pattern. The evidence examined is consistent with the hypothesis, but the nature of the causal connection between work participation and fertility is not directly demonstrated.

Quantized phase effect and Josephson tunneling

Abstract: By using properly defined sine and cosine phase variables, a model is proposed which yields a rigorous quantum-mechanical derivation of Josephson tunneling with exact current eigenstates. The model predicts that for dc tunneling the coherent fluids on both sides of the junction must be in the same state, and the "phase is quantized." This prediction can in principle be investigated experimentally, and may afford a fundamental test of quantum mechanics.

Gap effect on moiré patterns

Abstract: Nous analysons les caracteristiques principles des lignes de moire produitues par des reseaux, dont les deux plans ne coincident pas, illumines par la lumiere diffuse et non coherente. Nous etudions, les aspects physiques de la formation des lignes de moire et obtenons des equations qui donnent les valeurs des deformations fictives produites par la non-coincidence des plans du reseau temoin et du reseau deforme. Les resultats theoriques sont compares avec les mesures experimentales. L'ecart constate entre les deux valeurs correspond aux erreurs experimentales.