Showing papers by "State University of New York System published in 1969"

A Successive Approximations Approach to Character Weighting

Abstract: Fa~ris, J. S. (Dept. Biol. Sci., State Uniu., Stony Brook, New York 11790) 1969. A successive approximations approach to charaaer weighting. Syst. Zool., 18:374385.-Characters that are reliable for cladistic inference are those that are consistent with the true phyletic relationships, that is, those that have little homoplasy. A set of cladistically reliable characters are correlated with each other in a particular non-linear fashion here referred to as hierarchic correlation. Cladistically unreliable characters can be hierarchically correlated only by chance. A technique that infers cladistic relationships by successively weighting characters according to apparent cladistic reliability is suggested, and computer simulation tests of the technique are described. Results indicate that the successive weighting procedure can be highly successful, even when cladistically reliable characters are heavily outnumbered by unreliable ones. [Evolutionary taxonomy. Cladistics. Char-acter weighting.]

Choice as time allocation.

Abstract: When pigeons' standing on one or the other side of a chamber was reinforced on two concurrent variable-interval schedules, the ratio of time spent on the left to time spent on the right was directly proportional to the ratio of reinforcements produced by standing on the left to reinforcements produced by standing on the right. The constant of proportionality was less than unity for all pigeons, indicating a bias toward the right side of the chamber. The biased matching relation obtained here is comparable to the matching relation obtained with concurrent reinforcement of key pecks. The present results, together with related research, suggest that the ratio of time spent in two activities equals the ratio of the "values" of the activities. The value of an activity is the product of several parameters, such as rate and amount of reinforcement, contingent on that activity.

An Economic Disturbance Theory of Mergers

Abstract: Introduction, 624. — Economic disturbances and valuation discrepancies, 626. — Pursuit of monopoly and economies of scale as determinants of merger, 629. — Statistical tests, 631. — Security prices and valuation discrepancies, 637.

Play the Winner Rule and the Controlled Clinical Trial

Abstract: Consider a clinical trial to compare two treatments where response is dichotomous and patients enter the trial sequentially. This paper investigates the conduct of such a trial where the “Play the Winner Rule” (PWR) is used to assign patients to the different therapies. The implementation of the PWR in a clinical trial tends to place more patients on the better treatment. Both theoretical and numerical investigations show that over a wide range of situations this rule leads to near optimum results when used in a two-stage manner. Furthermore, these results are insensitive to optimum sample size requirements.

Circadian Rhythm of Optic Nerve Impulses Recorded in Darkness from Isolated Eye of Aplysia

Abstract: The isolated eye of the sea hare Aplysia califomica shows a circadian rhythm of optic nerve impulses when kept in total darkness. Peak activity on the first day of isolation occurs during the projected " dawn" of the light-dark cycle to which the whole animal had previously been entrained. Eyes from animals previously exposed to constant light show a free-running rhythm. This simple photoreceptor provides a quantized output with an ideal control (the other eye) for studies on rhythms.

Long-Range Order in One-Dimensional Ising Systems

Abstract: The argument of Landau and Lifshitz for the absence of long-range order in one-dimensional systems is used to show that order is absent if the interaction energy falls off faster than ${n}^{\ensuremath{-}2}$. When the interaction falls off as ${n}^{\ensuremath{-}2}$, the order cannot go continuously to zero.

The chemical anatomy of bone. I. A comparative study of bone composition in sixteen vertebrates.

Abstract: 1. Normal variations in the elementary composition of cortical bone from sixteen different adult vertebrates were studied. 2. Variations in the mineral (ash) and water content of bone exhibited what could be a necessary reciprocal relationship. 3. The mineral components, calcium, phosphorus and magnesium were positively correlated with hexosamine (ground substance) and negatively correlated with OH-proline (collagen). 4. Although positively correlated, the variations in total CO2, sodium and citric acid were much less specific. 5. All specimens exhibited a Ca/P molar ratio of 1.67 or larger depending on the amount of CaCO3 present. 6. These differences in bone composition undoubtedly have physiological significance and their further elucidation is necessary for the valid interpretation of experimental data in all areas of mineral metabolism.

Biological function of pancreatic ribonuclease.

Abstract: The physiological function of this much studied pancreatic enzyme has been misunderstood. It is essential only in ruminants and certain other herbivores, where it has a special function.

Lest I Forget Thee, Glutathione …

Abstract: Glutathione plays many parts in living organisms, and new methods for the oxidation of this tripeptide reveal some of them This review of the present situation ends with some suggestions for the future

Monoploids and monoploid-derivatives of maize (Zea mays L.)

Abstract: Looking forward, the study and use of monoploids and monoploid-derivatives appears more promising than it has at any time in the past. Of major interest are the cytological and physiological events of monoploid origin. One can hypothesize that precocious division of the egg prior to fertilization or during the initial stages of fertilization sets the stage for development of monoploid sporophytes, and further, that this precocious division results from premature deactivation or inadequate supply of an inhibiting substance present in the microenvironment or normal eggs. These hypotheses are subject to experimental verification. Answering the question whether the haploid sporophyte of maize is ‘truly’ monoploid is important to the understanding of the origin of the species. This is in part a question of semantics, as well as of homologies and homoeologies. It does seem likely that primitive maize or the generic ancestor of maize was an amphidiploid, the chromosomally-doubled product of hybridization of species of the Maydeae and Andropogoneae with a basic genome of five chromosomes. The pattern of crossing-over in monoploid meiosis, if there is a pattern, may provide evidence for homoeologies within the basic set of maize chromosomes. Agronomically, other than in the commercial breeding program for which I was personally responsible, little use has been made of the monoploid method in the development of homozygous diploids. Increased interest in and use of such radical techniques is likely in the future as the challenges of intensified commercial maize culture and of the highly competitive hybrid seedcorn market necessitate an increasingly high degree of responsiveness on the part of the maize breeder.

Ising Model with Second-Neighbor Interaction. I. Some Exact Results and an Approximate Solution

Abstract: The square Ising lattice with unequal first- and second-neighbor interactions has been considered. Among the exact results discussed, we show that the lowest energy state can be ferromagnetic, antiferromagnetic, or superantiferromagnetic, and the transition temperature should vanish in some cases. It is also shown that this problem is a special case of a more general problem arising in the statistical consideration of the hydrogen-bonded crystals. A well-defined approximation procedure is then introduced to solve the latter problem and to derive the (approximate) critical condition and expressions for the thermodynamic functions. The critical temperature thus determined is exact for the regular Ising lattice and for the lattices with ${T}_{c}=0$ while for the equivalent neighbor model the error is less than 2%. The specific heat possesses the usual logarithmic singularity in all cases.

Studies on the active transport of calcium in human red cells.

Abstract: The Ca++ transport mechanism in the red cell membrane was studied in resealed ghost cells. It was found that the red cell membrane can transport Ca++ from inside the cell into the medium against great concentration gradient ratios. Tracing the movement of 45Ca infused inside red cells indicated that over 95% of all Ca++ in the cells was transported into media in 20 min incubation under the optimum experimental conditions. The influence of temperature on the rate constant of transport indicated an activation energy of 13,500 cal per mole. The optimum pH range of media for the transport was between 7.5 and 8.5. As energy sources, ATP1, CTP, and UTP were about equally effective, GTP somewhat less effective, and ITP least effective among the nucleotides tested. The Ca++ transport does not appear to involve exchange of Ca++ with any monovalent or divalent cations. Also, it is not influenced by oligomycin, sodium azide, or ouabain in high concentrations, which inhibit the Ca++ transport in mitochondria or in sarcoplasmic reticulum. In these respects, the Ca++ transport mechanism in the red cell membrane is different from those of mitochondria and the sarcoplasmic reticulum.

The Diagnosis of Hypercortisolism. Biochemical Criteria Differentiating Patients from Lean and Obese Normal Subjects and from Females on Oral Contraceptives

Abstract: Hypercortisolism may be difficult to diagnose because the clinical features are sometimes unimpressive, or because current laboratory determinations may furnish misleading results. Studies have been performed on 40 lean subjects, 28 obese subjects, 15 females on oral contraceptives, 23 patients with long-standing paraplegia, 17 patients with undoubted features of Cushing's syndrome and chemical evidence of hypercortisolism, and 28 individuals with questionable hypercortisolism. The overlap between obese normal subjects and patients with hypercortisolism in urinary 17-OHCS excretion and cortisol secretion rates has been eliminated by expressing these measurements per gram of excreted creatinine. Patients with hypercortisolism invariably excreted more than the normal amounts of 17-OHCS (2.0–6.5 mg/day/g creatinine) and secreted more than normal amounts of cortisol (4.4–19.0 mg/day/g creatinine). Plasma 17-OHCS in patients with hypercortisolism was sometimes normal between 8 and 9 am [normal =19.2 ±...

Movement of cytoplasmic proteins into nuclei induced to enlarge and initiate DNA or RNA synthesis.

Abstract: In other studies it has been shown that somatic cell nuclei, which normally do not divide, are induced to enlarge and synthesize DNA when introduced into the cytoplasm of egg cells of Xenopus laevis. Introduction of such nuclei into the cytoplasm of large oocytes, however, causes nuclei to enlarge in a different way and to synthesize RNA but not DNA. In this study the proteins of eggs and oocytes were labelled with radioactive amino acids. Brain or blastula nuclei were then injected into cells containing labelled proteins under conditions in which protein synthesis was inhibited. Movement of cytoplasmic proteins was studied by observing the increase in acid-insoluble label over the injected nuclei by quantitative autoradiography. To prevent nuclear protein synthesis during the experiments, puromycin was injected with the nuclei. An estimation of the size of the labelled amino acid pool, a demonstration of the inhibitory effects of puromycin, and comparison of the amount of labelled material with and without puromycin all showed that protein synthesis in the nuclei played an insignificant role during the course of the experiments. A movement of acid-insoluble label from cytoplasm of egg cells into injected brain nuclei was noted even before they had begun to swell or synthesize DNA. In the initial period of nuclear enlargement there was a disappearance of the heterochromatic clumps characteristic of brain nuclei. This period coincided with a very rapid uptake of label to concentrations about twice that of the surrounding cytoplasm. A subsequent phase of nuclear swelling was characterized by a dilution of stainable nuclear material, loss of basophilia, and establishment of acidophilia of the nuclear contents. Cytoplasmic proteins continued to enter nuclei during this phase, but at a slower rate. Extraction of the soluble materials of labelled eggs with 0.01 M NaCl at pH 7.8 and a subsequent fractionation of the extract showed that there were many radioactive compounds present with molecular weights greater than 5000. The synthesis of DNA was initiated even before nuclear swelling could be detected, proceeding at least through the early stages of swelling. The induction of enlargement in blastula nuclei by oocyte cytoplasm containing labelled proteins was also accompanied by an uptake of label from the cytoplasm. In this case, although the uptake of unlabelled acidophilic material was much greater, the uptake of labelled proteins was much slower than that observed in the egg. The results are discussed in terms of chromosomal changes which occur during nuclear enlargement and during concomitant changes in nucleic acid metabolism.

A topologically interpenetrating elastomeric network

Abstract: While chemically different monomers can be mixed, the mixing of the corresponding polymers in the solid state usually results in (multiphase) polyblends. Even the mixing of two different polymer solutions generally produces two liquid phases. This difficulty can be overcome, without resorting to grafting, by producing interpenetrating polymer networks (IPN). By crosslinking an initially linear polymer in the presence of a crosslinked network we can produce a polymeric catenane or an IPN held together predominantly by “permanent” entanglements, assuming chain transfer reactions can be suppressed. Several workers have made IPN's from either chemically identical or chemically similar polymers and have studied their properties. In this work, two different elastomers, a crosslinked polyether-based poly(urethane-urea) and a linear poly(butadiene-acrylonitrile), as aqueous emulsions, are mixed, together with crosslinking agents and stabilizers, films cast, and subsequently cured to form the IPN. A parti...

Some Considerations on Nonlinear Realizations of Chiral SU ( 3 ) × SU ( 3 )

Abstract: We consider how nonlinear realizations of the chiral $\mathrm{SU}(3)\ifmmode\times\else\texttimes\fi{}\mathrm{SU}(3)$ symmetry arise in certain limits of models in which fields transform linearly under the group of transformations which leave the Lagrangian (approximately) invariant. All possible cases of nonlinear realizations of the chiral $\mathrm{SU}(3)\ifmmode\times\else\texttimes\fi{}\mathrm{SU}(3)$, wherein at least the $U(2)$ group generated by isospin and hypercharge is linearly represented, are considered. The connection between the nonlinear realizations and the spontaneous breakdown of the symmetry is made clear. Our results are clarified from a group-theoretic point of view, thereby establishing the connection between our results and a more general consideration of Coleman et al. We discuss theoretical and experimental implications of nonlinar realizations of the chiral $\mathrm{SU}(3)\ifmmode\times\else\texttimes\fi{}\mathrm{SU}(3)$, with reference to the $\ensuremath{\kappa}$ meson.

Multiple Drug Use Among Marijuana Smokers

Abstract: Knowledge of the process through which an individual progresses from the use of a relatively mild and almost innocuous herb as a “recreational” drug, to the sometimes frequent use of drugs which have at least the potential for damaging the body and the psyche, is patchy and conflicting. An adequate explanation of this movement simply does not exist. In light of these empirical and theoretical lacunae, we wish to offer an exploratory delineation of the use of other drugs by marijuana smokers. Although our data are too incomplete and fragmentary to yield a perspective firm and coherent enough to be called a “theory” of multiple drug use, we can, nonetheless, construct some tentative generalizations and hypotheses which should clarify and shed light on some dim corners of the field.