Showing papers by "Rutgers University published in 1977"

Nonlinear controllability and observability

Abstract: The properties of controllability, observability, and the theory of minimal realization for linear systems are well-understood and have been very useful in analyzing such systems. This paper deals with analogous questions for nonlinear systems.

Stages of Small-Group Development Revisited

Abstract: The purpose of this review was to examine published research on small-group development done in the last ten years that would constitute an empirical test of Tuckman's (1965) hypothesis that groups go through the stages of "forming," "storming," "norming," and "performing." Of the twenty-two studies reviewed, only one set out to directly test this hypothesis, although many of the others could be related to it. Following a review of these studies, a fifth stage, "adjourning," was added to the hypothesis, and more empirical work was recommended.

Large-distance and long-time properties of a randomly stirred fluid

Abstract: Dynamic renormalization-group methods are used to study the large-distance, long-time behavior of velocity correlations generated by the Navier-Stokes equations for a randomly stirred, incompressible fluid. Different models are defined, corresponding to a variety of Gaussian random forces. One of the models describes a fluid near thermal equilibrium, and gives rise to the usual long-time tail phenomena. Apart from simplifying the derivation of the latter, our methods clearly establish their universality, their connection with Galilean invariance, and their analytic form in two dimensions, $\ensuremath{\sim}\frac{{(logt)}^{\ensuremath{-}\frac{1}{2}}}{t}$. Nontrivial behavior results when the model is formally continued below two dimensions. Although the physical interpretation of the Navier-Stokes equations below $d=2$ is unclear, the results apply to a forced Burger's equation in one dimension. A large class of models produces a spectral function $E(k)$ which behaves as ${k}^{2}$ in three dimensions, as expected on the basis of equipartition. However, nonlinear effects (which become significant below four dimensions) control the infrared properties of models which force the Navier-Stokes equations at zero wave number.

Exchange-correlation energy of a metallic surface: Wave-vector analysis

Abstract: The exchange-correlation energy of a jellium metal surface is analyzed in terms of the wavelength of the fluctuations that contribute to it, using a three-dimensional scheme different from that used by other authors. It is shown that with this scheme there exists an exact limiting form at long wavelengths which includes all many-body correlations and which is independent of the surface density profile. The local-density approximation is formulated as a function of wavelength, and it is shown to be exact at short wavelength. The interpolation scheme between these limits, which was discussed previously, is formulated and checked more completely and used to calculate surface energies.

Involvement of hydrogen peroxide in the regulation of senescence in pear.

Abstract: Endogenous peroxide levels in pear fruit (Pyrus communis) were measured using a titanium assay method, and were found to increase during senescence in both Bartlett and Bosc varieties. Application of glycolic acid or xanthine, serving as substrates for the formation of H2O2, increased the peroxide content of the tissue and accelerated the onset of ripening, as measured by increased softening and ethylene evolution. Application of ethylene also induced increased peroxide levels. Ripening processes were similarly promoted when peroxides were conserved by inhibiting the activity of catalase with hydroxylamine or potassium cyanide. By comparison, the inhibition of glycolate oxidase with alphahydroxy-2-pyridinemethanesulfonic acid decreased the peroxide content of the tissue and delayed the onset of ripening. These results indicate that the onset of ripening correlates with the peroxide content of fruit tissues as occurring under normal conditions or as influenced by the treatments. Hydrogen peroxide may be involved in oxidative processes required in the initiation and the promotion of ripening.

Explication and test of a model of communicative competence

Abstract: This research investigated the concept of communicative competence. A definition and a five-component model of communicative competence is proposed. Interaction management, empathy, affiliation/support, behavioral flexibility, and social relaxation are identified as components of competence, with interaction management playing a central role. In an experiment designed to partially test the model, 239 Ss were assigned to evaluate a confederate's role-played communicative competence in one of four interaction management treatment conditions. Results indicated a strong, positive, linear relationship between interaction management and communicative competence. Positive correlations between competence and other components of the model were observed. The competent communicator is thus described as empathic, affinitive and supportive, and relaxed while interacting; he is capable of adapting his behavior as the situation within an encounter changes and as he moves from encounter to encounter. The manner in which the interaction is managed contributes, in part at least, to his fellow interact ants' perceptions of his competence.

Perceived lightness depends on perceived spatial arrangement

Abstract: The perceived shade of gray depends primarily on the luminance relationship between surfaces percieved to lie in the same plane and not between surfaces that are merely adjacent in the retinal image This result implies that depth perception must precede lightness perception and that lateral inhibition cannot explain lightness constancy

Lipids in Bacterial Taxonomy - A Taxonomist's View

Abstract: Written from a taxonomist's point of view and aimed primarily at other taxonomists, this review covers the types of lipids found in bacteria and actinomycetes, especially those reported in the recent literature, including fatty acids; glycerides; phospholipids; glycolipids; and amino acid-containing lipids including peptidolipids, peptidoglycolipids, sulfolipids, hydrocarbons, and waxes, and discusses their potential in taxonomy. Included are a survey of the recent findings on the stability of bacterial lipid patterns in terms of the effect of medium constituents and physical parameters of growth, age, and other factors and a short section on preferred methods of extraction, purification, and analysis.

Medial preoptic area and onset of maternal behavior in the rat.

Abstract: The present series of experiments examined whether the medial preoptic area (MPOA) is involved in the onset of maternal behavior in the rat. Previously, the MPOA had been shown to be important in the maintenance of maternal behavior in the lactating rat. The first experiment investigated whether estradiol benzoate (EB) acts on the MPOA to facilitate the onset of maternal behavior in the 16-day pregnant, hysterectomized, and ovariectomized female rat. Such rats when given EB implants in the MPOA had significantly shorter latencies for the onset of maternal behavior than had females implanted with cholesterol in the MPOA or with EB in the ventromedial hypothalamus, in mammillary bodies, or under the skin. A second experiment showed that estrogen-induced prolactin release was not involved in this facilitation. A third experiment indicated that MPOA lesions disrupt the onset of maternal behavior that is induced by pup stimulation in virgin females. It was concluded that the MPOA is involved not only in the maintenance of maternal behavior but in the hormonally mediated onset of maternal behavior and the onset of maternal behavior induced in virgin females by pup stimulation.

Natural antioxidants from rosemary and sage

Abstract: The presence of antioxidants in spices, specifically Rosemary and sage, is well known. However, the extracts of such spices usually have a strong odor and bitter taste and therefore cannot be used in most food products. This paper reports a patented process for the extraction of Rosemary and sage followed by a vacuum steam distillation of the extract in an edible oil or fat to obtain a bland natural antioxidant. Fractionation and characterization of the active antioxidant ingredient in the extract of Rosemary and sage is also reported.

Allelopathic Influence on Blue-Green Bloom Sequence in a Eutrophic Lake

Abstract: The bloom sequence in a eutrophic lake, Linsley Pond, over a period of 3 years is correlated to the effects of cell-free filtrates of dominant blue-green algae on both their successors and their predecessors. There is unbroken correspondence between the effects of heat-labile probiotic and antibiotic filtrates and the rise and fall of bloom populations in situ. All organisms in vitro were axenic or unialgal (bacterized) isolates from Linsley Pond.

Section-wise piecewise-linear functions: Canonical representation, properties, and applications

Abstract: This paper presents a new closed form analytical formula for representing n-dimensional surfaces and scalar functions of n variables which are piecewise-linear over each cross section obtained by freezing any combination of n - 1 of the n coordinates. This new section-wise piecewise-linear representation can be easily programmed with efficient computer storage. It is a global representation in the sense that a single formula is used to compute for f(x 1 ,x 2 ,...,x n ) for all values of (x 1 , x 2 ,...., x n ). Since this representation is expressed in closed analytic form, it allows standard mathematical operations and manipulations to be carried out in theorectical studies, In particular, it led to the possibility of deriving explicit closed form expressions for system parameters and design formulas. Examples are given which illustrate the potential applications of this representation in the modeling and analysis of nonlinear devices, circuits and systems.

Chemical quality index of canned tuna as determined by high-pressure liquid chromatography

Abstract: A chemical quality index of canned tuna was established for estimating the extent of decomposition in fresh tuna prior to canning. Histamine has frequently been used as such an indicator but by itself it has not always proved useful. The relationship of 5 amines (histamine, putrestine, cadaverine, spermine and spermidine) was studied to generate a chemical index of tuna decomposition. The amines were extracted from authentic pack and commercially prepared canned tuna samples. The dansyl derivatives were formed and determined by reverse phase, linear gradient elution, high pressure liquid chromatography. An index was developed from the individual amines and the resulting chemical indices scores compared favorably to organoleptic and authentic pack value scores.

Degradation of myofibrillar proteins by cathepsins B and D.

Abstract: 1. The procedure of Barrett [(1973) Biochem. J. 131, 809–822] for isolating cathepsins B and D from human liver was modified for use with rat liver and skeletal muscle. The purified enzymes appeared to be similar to those reported in other species. 2. Sephadex G-75 chromatography of concentrated muscle extract resolved two peaks of cathepsin B inhibitory activity, corresponding to molecular weights of 12500 and 62000. 3. The degradation of purified myofibrillar proteins by cathepsins B and D was clearly demonstrated by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. After incubation with enzyme, the polypeptide bands representing the substrates decreased in intensity and lower molecular weight products appeared. 4. Cathepsins B and D, purified from either rat liver or skeletal muscle, were shown to degrade myosin, purified from either rabbit or rat muscle. Soluble denatured myosin was degraded more extensively than insoluble native myosin. Degradation by cathepsin B was inhibited by lack of reducing agent, or by myoglobin, iodoacetic acid and leupeptin, but not by pepstatin. The same potential modifiers were applied to cathepsin D, and only pepstatin produced inhibition. 5. Rat liver cathepsin B had a pH optimum of 5.2 on native rabbit myosin. The pH optimum of cathepsin D was 4.0, with a shoulder of activity about 1pH unit above the optimum. 6. Rat liver cathepsins B and D were demonstrated to degrade rabbit F-actin at pH5.0, and were inhibited by leupeptin and pepstain, respectively. 7. The degradation of myosin and actin by cathepsin D was more extensive than that by cathepsin B.

The Microbiology of Aquatic Oil Spills

Abstract: Publisher Summary This chapter discusses the microbiology of aquatic oil spills. Immediately upon spilling, oil begins to undergo a series of physical and chemical changes. The processes causing these changes include spreading, emulsification, dissolution, evaporation, sedimentation, and adsorption. Collectively, the oil is weathered by these processes. The weathering of oil depends on the amount and type of oil spilled, and on environmental conditions. Petroleum hydrocarbons have only a very limited solubility in water. Therefore, most oil spillages initially form a surface slick. The surface slick can be moved by wind, wave, and current action. A surface oil slick immediately begins to spread, initially owing to gravitational forces, resulting in a thinner layer of oil covering a larger area. The viscosity of the spilled oil will, to some extent, influence the rate of spreading and, as viscosity is temperature dependent, water temperature will also influence the area covered by a surface slick. The chapter illustrates the effects of petroleum hydrocarbons on microorganisms, microbial emulsification and degradation of petroleum, and the microorganisms and oil pollution abatement.

Activation of Estrous Behavior in Ovariectomized Rats by Intracerebral Implants of Estradiol Benzoate

Abstract: There is a lack of agreement among several studies on the site of action of estradiol in the regulation of estrous behavior in mammals in general, and in rats in particular. Two experiments were performed in an attempt to clarify this issue. In the first experiment, 29 ovariectomized rats received unilateral 27 gauge implants of estradiol benzoate (EB) in various areas of the brain. Animals were tested over a three week period for estrous responses to an intact male rat. The greatest response resulted from implants in the ventromedial hypothalamus (VMH). Implants in the preopticanterior hypothalamic region (POA-AH) and other areas of the brain were significantly less effective, but when progesterone (P) was given almost all animals responded, and the magnitude of responses did not differ among the various groups. In the second experiment 30 gauge tubing with EB in the lumen was employed in order to restrict the effective dose of hormone delivered to the brain. Implants were placed in the VMH, POA-AH, or i...

The triple helix ⇌ coil conversion of collagen‐like polytripeptides in aqueous and nonaqueous solvents. Comparison of the thermodynamic parameters and the binding of water to (L‐Pro‐L‐Pro‐Gly)n and (L‐Pro‐L‐Hyp‐Gly)n

Abstract: The collagen-like peptides (L-Pro-L-Pro-Gly)n and (L-Pro-L-Hyp-Gly)n with n = 5 and 10, were examined in terms of their triple helix ⇌ coil transitions in aqueous and nonaqueous solvents. The peptides were soluble in 1,2-propanediol containing 3% acetic acid and they were found to form triple-helical structures in this solvent system. The water content of the solvent system and the amount of water bound to the peptides were assayed by equilibrating the solvent with molecular sieves and carrying out Karl Fischer titrations on the solvent phase. After the solvent was dehydrated, much less than one molecule of water per tripeptide unit was bound to the peptides. Since the peptides remained in a triple-helical conformation, the results indicated that water was not an essential component of the triple-helical structure. Comparison of peptides with the same chain length demonstrated that the presence of hydroxyproline increased the thermal stability of the triple helix even under anhydrous conditions. The results, therefore, did not support recent hypotheses that hydroxyproline stabilizes the triple helix of collagen and collagen-like peptides by a specific interaction with water molecules. Analysis of the thermal transition curves in several solvent systems showed that although the peptides containing hydroxyproline had tm values which were 18.6° to 32.7°C higher, the effect of hydroxyproline on ΔG was only 0.1 to 0.3 kcal per tripeptide unit at 25°C. The results suggested, therefore, that the influence of hydroxyproline on helical stability may be explained by intrinsic effects such as dipole–dipole interactions or by changes in the solvation of the peptides by alcohol, acetic acid, and water. A direct calorimetric measurement of the transition enthalpy for (L-Pro-L-Pro-Gly)n in 3% or 10% acetic acid gave a value of −1.84 kcal per tripeptide unit for the coil-to-helix transition. From the value for enthalpy and from data on the effects of different chain lengths on the thermal transition, it was calculated that the apparent free energy for nucleation was +5 kcal/mol at 25°C (apparent nucleation parameter = 2 × 10−4M−2). The value was dependent on solvent and on chemical modification of end groups.

Characteristics of the chloride conductance in muscle fibers of the rat diaphragm.

Abstract: In muscle fibers from the rat diaphragm, 85% of the resting membrane ion conductance is attributable to Cl-. At 37 degree C and pH 7.0, GCl averages 2.11 mmho/cm2 while residual conductance largely due to K+ averages 0.34 mmho/cm2. The resting GCl exhibits a biphasic temperature dependence with a Q10 of 1.6 between 6 degree C and 25 degree C and a Q10 of nearly 1 between 25 degree C and 40 degree C. Decreasing external pH reversibly reduced GCl; the apparent pK for groups mediating this decrease is 5.5. Increasing pH up to 10.0 had no effect on GCl. Anion conductance sequence and permeability sequence were both determined to be Cl-greater than Br-greater than or equal to I-greater than CH3SO4-. Lowering the pH below 5.5 reduced the magnitude of the measured conductance to all anions but did not alter the conductance sequence. The permeability sequence was likewise unchanged at low pH. Experiments with varying molar ratios of Cl- and I- indicated a marked interaction between these ions in their transmembrane movement. Similar but less striking interaction was seen between Cl- and Br-. Current-voltage relationships for GCl measured at early time-points in the presence of Rb+ were linear, but showed marked rectification with longer hyperpolarizing pulses (greater than 50ms) due to a slow time-and voltage-dependent change in membrane conductance to Cl-. This nonlinear behavior appeared to depend on the concentration of Cl- present but cannot be attributed to tubular ion accumulation. Tubular disruption with glycerol lowers apparent GCl but not GK, suggesting that the transverse tubule (T-tubule) system is permeable to Cl- in this species. Quantitative estimates indicate that up to 80% of GCl may be associated with the T tubules.

Effect of Temperature, Aeration, and Moisture on CO(2) Formation in Bench-Scale, Continuously Thermophilic Composting of Solid Waste.

Abstract: A compost production system was employed to supply uniform material for controlled experiments of factorial design. Over a 96-h composting period, the cumulative amount of CO2 evolved was maximal at 56 to 60°C, an aeration rate that left an O2 residual of 10 or 18% in the exhaust gas and a moisture content of 60% wet weight. Carbon dioxide evolution was submaximal at 64°C and higher.

On the Inhibition of Muscle Membrane Chloride Conductance by Aromatic Carboxylic Acids

Abstract: 25 aromatic carboxylic acids which are analogs of benzoic acid were tested in the rat diaphragm preparation for effects on chloride conductance (G(Cl)). Of the 25, 19 were shown to reduce membrane G(Cl) with little effect on other membrane parameters, although their apparent K(i) varied widely. This inhibition was reversible if exposure times were not prolonged. The most effective analog studied was anthracene-9-COOH (9-AC; K(i) = 1.1 x 10(-5) M). Active analogs produced concentration-dependent inhibition of a type consistent with interaction at a single site or group of sites having similar binding affinities, although a correlation could also be shown between lipophilicity and K(i). Structure-activity analysis indicated that hydrophobic ring substitution usually increased inhibitory activity while para polar substitutions reduced effectiveness. These compounds do not appear to inhibit G(Cl) by altering membrane surface charge and the inhibition produced is not voltage dependent. Qualitative characteristics of the I-V relationship for Cl(-) current are not altered. Conductance to all anions is not uniformly altered by these acids as would be expected from steric occlusion of a common channel. Concentrations of 9-AC reducing G(Cl) by more than 90 percent resulted in slight augmentation of G(I). The complete conductance sequence obtained at high levels of 9-AC was the reverse of that obtained under control conditions. Permeability sequences underwent progressive changes with increasing 9-AC concentration and ultimately inverted at high levels of the analog. Aromatic carboxylic acids appear to inhibit G(Cl) by binding to a specific intramembrane site and altering the selectivity sequence of the membrane anion channel.

Progesterone: its role in the central nervous system as a facilitator and inhibitor of sexual behavior and gonadotropin release.

Abstract: When the action of a hormone on a tissue is studied, the biochemical condition of the tissue or substrate prior to administration of the hormone should always be considered. Diverse factors, such as genetic sex, nutritional state, temperature, time of day, and season of year, may influence the substrate. Only when these and other factors are controlled for can one be sure that experimental samples begin from a relatively homogeneous baseline, and only in this way can one accurately assess the effects of a hormone on this baseline. Extraordinary emphasis on this stricture is required for progesterone and its actions on neural and genital tissues. This is so because the effects of progesterone are very much dependent on the previous, concurrent, and subsequent influences of estrogenic hormones on target tissue substrates. These temporal factors determine whether progesterone will facilitate or inhibit estrogen-dependent processes. In this paper, we will first describe, at a molar level, the interaction of progesterone with estrogen-sensitive neural tissues that regulate the expression of female sexual behavior and the release of gonadotropic hormones. Later, we will discuss, at a biochemical level, possible mechanisms by which progesterone can exert both facilitatory and inhibitory influences on sexual behavior and gonadotropin release. This section will include data on estrogen and progesterone uptake and on possible mediation of progesterone effects by neurotransmitters. Also included in this discussion will be a comparison between the inhibitory actions of progesterone and those of synthetic antiestrogens on estrogen-dependent neural processes. To conclude, we will suggest that progesterone-sensitive neural systems operate with a precision that is attributable more to interneuronal channeling of information to or from estrogen-sensitive areas than to intranuclear programming of biochemical events.

Effects of tide cycles on habitat selection and habitat partitioning by migrating shorebirds

Abstract: -We studied assemblages of feeding shorebirds in three intertidal habitats on the coast of New Jersey during August to document how species segregate spatially both among and within habitats and to determine the effects of tidal cycles on these patterns. The habitats were a sandy beach facing the ocean proper (outer beach), a sandy beach on the mainland side of a barrier island (inner beach), and a small mudflat adjacent to a Spartina alterniflora salt marsh. We were able to identify several microhabitats on the outer beach and mudflat. Most species fed in more than one habitat, but only two, Charadrius semipalmatus and Calidris canutus, used all three habitats regularly. Within habitats, most species exhibited strong preferences for the wettest areas, but we found differences among species in degrees of preference. The least amount of partitioning occurred on the inner beach, where birds crowded into a small zone near the water's edge and had frequent agonistic encounters suggesting intense competition. Shorebird feeding activity was partly a function of tide time: each habitat had a characteristic temporal pattern of use by shorebirds related to tide time rather than diel time; within habitats, we found species-characteristic feeding activity rhythms that were also a function of tide time. Feeding by most species peaked during the first 2 hours after low tide on the outer beach and mudflat. The results are discussed in terms of feeding strategies and interspecific competition.-Department of Biology, Livingston College, Rutgers University, New Brunswick, New Jersey 08903 (Burger, Chase); National Fish and Wildlife Laboratory, National Museum of Natural History, Washington, D.C. 20560 (Howe); and Institute of Animal Behavior, Rutgers University, Newark, New Jersey 07102 (Hahn). Present address of Chase: Department of Biology, Barnard College, New York, N.Y. 10027. Accepted 11 March 1977. (This paper was subsidized by the Migratory Bird Program, U.S. Fish and Wildlife Service.) ALTHOUGH usually solitary on their breeding grounds, migrating shorebirds (Charadrii) often form large, mixed-species aggregations that feed along coastal beaches, mudflats, and marshes. These concentrations of shorebirds result in high population densities in prime feeding areas (Recher and Recher 1969). As these habitats are effectively two-dimensional, spatial segregation of flock members can only occur in a horizontal plane. Increased density may lead to more intense competition for space, resulting in more frequent aggressive interactions and/or niche partitioning. Moreover the cyclic tidal inundation of mudflats and beaches causes changes both in the available feeding space and in the diversity and availability of prey items. Shorebirds respond to these changes by moving continually from one foraging area to another. Studies of ecology of migrating and wintering shorebirds have dealt primarily with feeding methods and rates (Goss-Custard 1969, Ashmole 1970, Burton 1972, Baker and Baker 1973, Baker 1974), feeding dispersions (Goss-Custard 1970a), prey densities (Bengtson and Svensson 1968, Brooks 1967, Goss-Custard 1970b), feeding ecology (Recher 1966, Thomas and Dartnall 1971, Holmes 1966, Holmes and Pitelka 1968), and aggressive behavior (Hamilton 1959, Recher and Recher 1969). Most of these studies stress behavior and diet as related to prey availability or broader ecological considerations. Collectively, most data suggest that shorebird species overlap broadly in their diets and feeding habitats. Competitive exclusion may be avoided because species move from point to point without fully exploiting the available food reserves (Recher 1966). Some studies have also identified patterns of niche partitioning with respect to foods, feeding methods, 743 The Auk 94: 743-758. October 1977 This content downloaded from 157.55.39.211 on Tue, 09 Aug 2016 05:06:27 UTC All use subject to http://about.jstor.org/terms 744 BURGER ET AL. [Auk, Vol. 94

Social Networks and Pathways to Psychiatric Treatment

Abstract: Cultural interpretations have dominated the study of class differences in entering psychiatric treatment. This study compares the power of cultural variables and structural variables to predict the entry into psychiatric treatment. The concept of the social network is used to show that structural relationships, in addition to the culture of the different social classes, are important predictors of psychiatric labels and referrals, severity of symptoms, and duration of symptoms in the community. Interviews with 120 outpatients and short-term inpatients at a community mental health center provide the data for the study. The findings support the hypothesis that structural variables are important determinants of the pathways into psychiatric treatment and point to the need to link the structure of social networks to the content of networks. Studies of psychiatric help-seeking have emphasized the cultural forces predisposing individuals to enter psychiatric treatment. Sociologists have paid particular attention to the attitudes, knowledge, and verbal skills of persons of various social class backgrounds (Dohrenwend and Chin-Song; Gove and Howell; Hollingshead and Redlich; Myers and Roberts). For example, middle-class persons have more favorable attitudes toward psychiatry and greater knowledge to correctly identify psychiatric disorders than lower-class people, leading them to enter psychiatric treatment with less severe problems and in shorter periods of time (Gove and Howell). In addition, the greater intellectual sophistication of the middle and upper classes makes them more likely to initiate hospitalization themselves while the lack of such sophistication among the lower classes makes social control agents more likely to initiate hospitalization (Gove and Howell). The primary causal factor in these studies has been different cultural attitudes -how they lead to different behavior patterns in psychiatric help-seeking. Recently, researchers have questioned this preoccupation with cultural forces and have used structural patterns of interaction to predict