Showing papers by "University of Maine published in 1971"

Phytoplankton sampling with the sedgwick-rafter cell1

Abstract: Quantitative processing of large numbers of phytoplankton collections requires a sampling method that will yield precise and reproducible estimates of abundance within an acceptably short counting time. A two-stage sampling plan was developed, using the Sedgwick-Rafter cell, which satisfies these criteria. The sampling design is appropriate for larger phytoplankton species (> 10–15 µ) having relatively high population densities (⩾ 105 cells/liter) .

Second-order schedules and the problem of conditioned reinforcement.

Abstract: Thirteen pigeons were exposed to a variety of second-order schedules in which responding under a component schedule was reinforced according to a schedule of reinforcement. Under different conditions, completion of each component resulted in either (1) the brief presentation of a stimulus also present during reinforcement (pairing operation), (2) the brief presentation of a stimulus not present during reinforcement (nonpairing operation), or (3) no brief stimulus presentation (tandem). Brief-stimulus presentations engendered a pattern of responding within components similar to that engendered by food. Patterning was observed when fixed-interval and fixed-ratio components were maintained under fixed- and variable-ratio and fixed- and variable-interval schedules. There were no apparent differences in performance under pairing and nonpairing conditions in any study. The properties of the stimuli presented in brief-stimulus operations produced different effects on response patterning. In one study, similar effects on performance were found whether brief-stimulus presentations were response-produced or delivered independently of responding. Response patterning did not occur when the component schedule under which a nonpaired stimulus was produced occurred independently of the food schedule. The results suggest a reevaluation of the role of conditioned reinforcement in second-order schedule performance. The similarity of behavior under pairing and nonpairing operations is consistent with two hypotheses: (1) the major effect is due to the discriminative properties of the brief stimulus; (2) the scheduling operation under which the paired or nonpaired stimulus is presented can establish it as a reinforcer.

Effects of symmetrical and asymmetrical changeover delays on concurrent performances.

Abstract: Two variable-interval 3-min schedules functioned concurrently to arrange reinforcement of a pigeon's pecks on a single key, the main key. Each schedule was associated with a distinct color of the main key; a response on a second key alternated the color and schedule assignment of the main key. A changeover delay, a period of time following schedule and key-color alternation during which reinforcement of responding on the main key could not occur, was arranged with equal or with unequal durations for the two directions of alternation. Durations were varied from 0.33 sec to 27 sec, in addition to no delay. With equal delays for the two directions of alternation, the pigeon alternated the schedules less often the larger the delay duration. When the delays in the two directions of alternation were unequal, it could be shown that alternation of the schedules was reduced both by a delay just incurred by the last alternation and by a. delay to be incurred by the next. The latter delay was more potent in reducing the frequency of alternations.

Mass transfer and drag coefficients of bubbles rising in dilute aqueous solutions

Abstract: The effects of aliphatic alcohols on mass transfer and drag coefficients of a carbon dioxide bubble were investigated in very dilute aqueous solutions. A high speed photography technique provided an almost continuous record of the bubble volume, shape, and oscillation, as related to the height of the bubble in the liquid and the time elapsed from the moment of its release. The results showed that the concentration, molecular size, and structure of the investigated alcohols have a pronounced effect on mass transfer as well as drag coefficients of the rising bubble. The significance of these effects with respect to idealized models of a highly circulating bubble and a solid sphere was considered, and a functional relationship was found to exist. This relationship may be applied to systems more complex than a single bubble.

Coturnix coturnix japonica

Abstract: The materials for the karyograms were prepared from feather pulp and embryonic tissue of coturnix quail secured through the courtesy of Dr. Hans Abplanalp, University of California, Davis. This colony originated from Japan. This species is one of the few among the birds so far described that have metacentric or submetacentric chromosomes recognizable to about chromosome size twenty.

Xenopus laevis Daudin

Abstract: The pair of large acrocentric autosomes bears a secondary constriction and satellites on the short arm.

Simple Shell-Model Calculation of Lattice Dynamics and Thermal Expansion of Alkali Halides

Abstract: A six-parameter shell model which takes into account anion polarizability, noncentral nearest-neighbor interactions, central second-neighbor interactions, and the effective charge of the core and shell of the anion has been utilized for the determination of the lattice dynamics of LiF, NaCl, KCl, and RbI. The model parameters are determined from experimental data on the long-wavelength optical-mode phonon frequencies, the three elastic constants, and the high- and low-frequency dielectric constants. By the incorporation of the pressure derivatives of these quantities into the lattice-dynamical model, the individual-mode Gr\"uneisen parameters and the temperature dependence of the thermal-expansion coefficient are calculated. Reasonable agreement is found between the calculated values and the available experimental data on these quantities.

Weak electric and magnetic fields in fish orientation.

Abstract: The potential roles of the geomagnetic and geoelectric fields in the orientation and navigation of fishes have not been advanced with the same vigor as they have for birds. Yet these earthly cues are just as available to fishes, perhaps more so. Fishes and other aquatic animals might use the geomagnetic field directly to obtain a compass reference direction or to follow lines of equal intensity or gradients of intensity. Since a conductor moving through a magnetic field generates an electromotive force, two possible indirect means by which an organism could obtain orientational information from the Earth's magnetic field are provided. Fishes, particularly marine species, might sense the electric fields generated by ocean currents moving through the Earth's magnetic Or an animal might sense the electric field generated within its own body as it moves in the geomagnetic Additionally, periodic variations in the geomagnetic field might serve as biological clock setters in Evidence for (or against) direct detection of weak magnetic fields by fishes is lacking. By contrast an almost incredible sensitivity to electric fields has been demonstrated for some groups of fishes. The weakly electric fishes (Gymnotidae. M ~ r m y r i d a e ) ~ J ~ J ~ can detect potentials as low as 0.03 p v cm-', sharks (Scyliorhinus cuniculu) and skates (Raja c l a v u t ~ ) , ~ ~ ~ ~ as low as 0.01 p v cm-I, and bullheads (Zctulurus nebulosus),'e as low as 30 p v cm-'. All these groups have known receptor organs. Recently Royce and coworkers5 hypothesized that Pacific salmon (Oncorhynchus) migrate following Ocean currents, but swim at speeds greater than those of the water current. They strongly suggested the possibility of electronavigation by the salmon, but noted the lack of any information on electrical sensitivity of salmonids. In fact such information is lacking for all the long-distance migrating fishes. Based on this complete lack of data on electroand magnetosensitivity of migratory fishes, and in view of their potential roles in orientation and navigation, we have begun a series of investigations to determine if migratory fishes have sufficient sensitivity to allow such use of the available geoelectric and geomagnetic cues. These investigations involve the American eel (Anguillu rostratu) and the Atlantic salmon (Sulmo sular), two long distance migrators whose migration routes and orientation mechanisms are largely unknown. Our studies are at an early stage, and this paper will report the findings to date.

Some Burning Characteristics of Filter Paper

Abstract: The downward rate of spread of a free-burning fire in a single piece of filter paper has been studied experimentally The internal temperature distribution in the paper is calculated from a numerical solution of the two-dimensional heat conduction equation Net heat flux from the flame can be computed, and a model for the burning zone tested by comparing measured and computed char zone lengths Correlation is good, suggesting that a simple model of the pyrolysis process is valid

On sets having finitely many points of local nonconvexity and propertyP m

Abstract: If a pointq ofS has the property that each neighborhood ofq contains pointsx andy such that the segmentxy is not contained byS, q is called a point of local nonconvexity ofS. LetQ denote the set of points of local nonconvexity ofS. Tietze’s well known theorem that a closed connected setS in a linear topological space is convex ifQ=φ is generalized in the result:If S is a closed set in a linear topological space such that S ∼ Q is connected and |Q|=n<∞,then S is the union of n+1or fewer closed convex sets. Letk be the minimal number of convex sets needed in a convex covering ofS. Bounds fork in terms ofm andn are obtained for sets having propertyP m and |Q|=n.

Discrimination of compound stimuli involving the presence or absence of a distinctive visual feature.

Abstract: Pigeons learned a free operant, go/no-go discrimination between stimuli produced by rapid alternation of different features on the response key. The 0 degrees -B compound consisted of a vertical black line on a white background (the 0 degrees feature) alternated with a blank white field (the B feature), with successive 0.75-sec feature on periods separated by 0.20-sec dark periods. Pecks at the alternating 0 degrees and B features were recorded separately. When pecks at the 0 degrees -B compound were reinforced and pecks at the B-B stimulus (repeated brief presentations of the B feature) were extinguished, the birds pecked more at the 0 degrees feature than at the B feature in the 0 degrees -B compound; subsequently, decremental line-tilt generalization gradients were obtained. When pecks at B-B were reinforced and pecks at 0 degrees -B were extinguished, the rate of pecking at the 0 degrees feature decreased to a low level much more rapidly than did the rate of pecking at the B feature in the 0 degrees -B compound; incremental line-tilt gradients were obtained. Following training with pecks at 0 degrees -B reinforced and pecks at 0 degrees -0 degrees extinguished, incremental line-tilt gradients were obtained, whereas the gradients were decremental following training with 0 degrees -0 degrees reinforced and 0 degrees -B extinguished.

Abnaki: A new high-yielding potato variety resistant to verticillium wilt and leaf roll

Abstract: Abnaki, a new potato variety, was released February 18, 1971, by the Plant Science Research Division of the United States Department of Agriculture, the Maine Agricultural Experiment Station, and the New York Agricultural Experiment Station. Abnaki, tested under the pedigree number B5415-6, was selected from a crose between U S D A seedling X1276-185 and B4116-2. Approximately 380 seedlings from this cross were grown from true seed in the greenhouse at Beltsville, Maryland in 1961. Abnaki was one of 20 saved from single-hill selections from the 1962 increase in Maine.

Characterization of Kuratowski 14-Sets

Abstract: (1971). Characterization of Kuratowski 14-Sets. The American Mathematical Monthly: Vol. 78, No. 4, pp. 362-367.

Emotional arousal as a function of perceived locus of control and task requirements.

Abstract: (1971). Emotional Arousal as a Function of Perceived Locus of Control and Task Requirements. The Journal of Social Psychology: Vol. 83, No. 2, pp. 185-191.

Ordering in the Smectic Phase Owing to Electric Fields

Abstract: A recent article contained results which showed that in the smectic phase of ethyl-[p-(p-methoxybenzylidene)amino] cinnamate, the molecules preferred a direction with the long axes parallel to a 5000 Hz electric field and perpendicular to a dc field. It was suggested that the anomalous effect in the dc field might be associated with the conductivity anisotropy, since the conductivity was greatest in a direction perpendicular to the long axes of the molecules in the smectic phase. Results are presented which show how the ordering varies with the frequency of the applied field for frequencies below 5000 Hz in the smectic phase of ethyl-[p-(p-methoxybenzylidene)amino] cinnamate. The ordering in the nematic phase of this material owing to dc and ac electric fields is also described. A few comments are made concerning the nematic and smectic phases of p-heptyloxybenzoic acid.

Brachymeria intermedia (hymenoptera: chalcididae) parasitizing gypsy moth in maine

Abstract: Brachymeria intermedia (Nees), an introduced parasite of the gypsy moth, was recovered from gypsy moth pupae collected in Fryeburg, Maine (latitude 44°). The recovery of this parasite in Maine shortly after it was reported established on gypsy moth in Connecticut suggests that B. intermedia is rapidly expanding its range. The wide range of hosts attacked by the parasite, and its occurrence in northern New England, make it a promising potential biotic agent on a variety of northern pest species of lepidopterans, either through natural spread or by artificial introduction.

Effect of a signal previously paired with free food on operant response rate in pigeons

Abstract: In Phase 1, food was presented independently of the birds’ behavior. In one group, the food was paired with an auditory CS; in the other group, CS and food occurred randomly. In Phase 2, the birds were trained to peck a key for variable-interval food reinforcement, with CS off. Then, following additional Phase 1 training, they were tested with CSs presented during operant extinction. For both key pecking and a photocell measure of activity near the speaker, the CS produced changes in behavior which, when measured independently of the direction of change, were significantly greater in the paired group than in the random group.