Showing papers by "University of Maine published in 1968"

Parameters of Microstrip Transmission Lines and of Coupled Pairs of Microstrip Lines

Abstract: A theoretical analysis is presented of microwave propagation on microstrip, with particular reference to the case of coupled pairs of microstrip lines. Data on this type of transmission line are needed for the design of directional couplers, filters, and other components in microwave integrated circuits. The inhomogeneous medium, consisting of the dielectric substrate and the vacuum above it, is treated in a rigorous manner through the use of a "dielectric Green's function" which expresses the discontinuity of the fields at the dielectric-vacuum interface. Results are presented in graphical form for substrate dielectric constants of 1, 9, and 16, and a range of values of width and spacing of the strips. Numerical tables for these and other cases are also available. The tables present capacitance, characteristic impedance, and velocity of propagation of the even and odd normal modes. The method lends itself to the treatment of other geometries which are of practical interest, such as "thick" strips, presence of an unsymmetrically located upper ground plane, etc.

Potato vine killing

Abstract: Killing potato vines as a pre-harvest practice has become widely accepted in the United States and Canada particularly where potatoes are stored for extended periods of time. Reasons for killing potato vines are many and vary among production areas. In general potato vines are usually killed for one or rnore of the following reasons 1. To prevent oversized, knobby, and second growth tubers. 2. To prevent spread of virus diseases by late aphid infestations. 3. To kill late blight spores on foliage and surface of soil. 4. To reduce late blight tuber rot infection. 5. To make both machine and hand harvesting easier by elimination of vines and weeds. 6. To terminate growth of potato crop whenever desirable from the standpoint of quality or to take advantage of early market demands. 7. To hasten plant maturity as a precursor for hardening or \"setting\" skin of tubers to reduce skinning, bruising, and storage shrinkage losses. 8. To permit harvesting when labor supply is available or when weather conditions are most favorable. 9. To facilitate early harvesting of seed potatoes in order to increase percentage of seed-size tubers and also to preserve \"seed vitality\" often associated with immature tubers. 10. In some areas, to get the potato crop harvested before game hunting season opens.

Isolation and biology of aStreptomyces sp. causing potato scab in soils below pH 5.0

Abstract: Isolates of an acid tolerantStreptomyces sp. were obtained from lesions of potatoes grown in soil with a pH below 5.0. Isolates ofS. scabies were obtained only from lesions of tubers grown in soil with the pH above 5.2. Isolates of the acid tolerantStreptomyces sp. caused tuber lesions on potatoes grown in soil at pH 4.5 or 5.9. Isolates ofS. scabies were pathogenic in soil at pH 5.9, but not 4.5. Physiological tests and morphological observations suggest that the acid tolerant organism is notS. scabies. It is believed thatStreptomyces sp. is a causal agent of potato scab in acid soils.

Wabanaki “Family Hunting Territories”

Abstract: It is now generally concluded that hunting and trapping territories developed among the Northern and Eastern Algonquian Indians largely as a result of the fur trade and other factors directly connected with European colonization. Although this appears to be a valid conclusion, this article argues that both prior and subsequent conditions were unique in the case of the Eastern Algonquian in general and the Wabanaki in particular. Evidence for a riverine orientation and the regular exploitation of the beaver in aboriginal time indicates that Wabanaki territoriality was quite different from that described for the Northern Algonquian, and that its development did not require an abrupt shift away from previous patterns.

Photo-inhibition of cell division and growth in euglenoid flagellates.

Abstract: Visible light of moderate intensity causes two and perhaps three types of division inhibition in Euglena gracilis are related cells. Fluorescent light causes a general inhibition of growth and division which is temperature-dependent. Pigmentation or complex organic media partially lifts this inhibition. A second type of inhibition, which is transient, can be caused by either fluorescent or incandescent light, and is found with an irreversibly bleached strain of Euglena grown on a limiting concentration of acetate; this inhibition could not be demonstrated in cells grown on limiting concentrations of glucose.

Effect of tetrachloronitrobenzene (Fusarex) on emergence and yield of potatoes. Part II. — Northeast

Abstract: Seed potatoes of the Katahdin, Kennebec, and Pungo varieties were treated with Fusarex dust containing 6% tetrachloronitrobenzene at three dates in Maine during 1961–62 storage season. In 1962, these chemically treated seed potatoes were planted in uniform tests and compared with seed stocks that had been desprouted once and also with untreated seed tubers. Cooperators in Maine, Long Island, and New Jersey, Pennsylvania, and New Brunswick, Canada recorded plant emergence and yield data at each location. Treatment of seed potatoes with Fusarex delayed initial plant emergence of all varieties at all locations except in Maine and Canada where Fusarex treatment increased emergence of the Pungo variety as compared to untreated seed. Total emergence varied by variety and location. Date of seed treatment with Fusarex did not affect emergence significantly. Emergence of desprouted seed tubers was not significantly lower than untreated or chemically treated seed at most locations. Treatment of seed with Fusarex decreased yields of tubers in Pennsylvania and on Long Island. At all other locations yields were slightly better when seed had been treated with Fusarex. No significant statistical differences in yields occurred between treatments at any of the five test locations when varieties and locations were aceraged.

Effects of environmental temperature-humidity and cage density on body weight and behavior in mice

Abstract: Es wurden Mause des C3H/HeJ-Stammes nach Entwohnung bis zum Alter von 125 Tagen unter verschiedenen Umweltbedingungen wie Temperatur, relative Luftfeuchtigkeit und Kafigdichte aufgezogen. Je hoher Temperatur, relative Luftfeuchtigkeit und je grosser die Kafigdichte, um so grosser waren die Korpergewichtsverluste. Umwelttemperatur, Feuchtigkeit und Kafigdichte beeinflussten zusammen das Uberleben der Mause nach Schwimmen.

Stability and Instability: A Note in Comparative Political Analysis

Abstract: C OMPARATIVE POLITICAL ANALYSTS are presented with a variety of manifestations of political instability among which, for example, are unstable democracies, unstable dictatorships, and fragmented societies. Within each category of unstable society, moreover, there is, both empirically and speculatively, an infinite gradation. The purpose of the present paper, while heuristic in nature, is, first to identify political stability and second, to delineate two broad but significant categories of political instability. There is an underlying hope that such an effort will elicit meaningful hypotheses concerning a theory of political development.1

Abstracts of papers presented at the Fifty-Second Annual Meeting of The Potato Association of America

Abstract: F I F T Y S E C O N D A N N U A L M E E T I N G

A Histological Study of White Pine Shoots Attacked by the Exsule Stage of Pineus pinifoliae

Abstract: The stylets of the exsule stage of the pine leaf chermid, Pineus pinifoliae (Fitch), follow an intercellular course through the cortex of white pine and terminate in the young sieve cells of the phloem. Phloem deterioration is a gradual process commencing in late June and reaching a climax in late August. This damage is characterized by hypertrophied sieve cells and cellular breakdown in the phloem region, destruction of vascular cambium, and ultimately, in the formation of large structureless cavities surrounding the xylem. Internal deterioration is evidenced externally by needle discoloration followed by twig drooping. This sequence of events is directly related to the order of tissue abnormalities within the shoot.

The adult cervicothoracic musculature of the cockroach, Nauphoeta cinerea (Olivier)

Abstract: The cervicothoracic musculature of the adult cockroach, Nauphoeta cinerea (Olivier) is described for the first time. The adult thoracic ventral intersegmental muscles are compared with those of the nymph and of the adult cockroach, Periplaneta americana (Linnaeus).

Interests of Engineering Graduates According to Undergraduate Curricula

Abstract: This report describes a study of the interests of students who graduated from different engineering specialties at the University of Maine. 90 graduates in each of 5 specialties were selected for study. The Strong Vocational Interest Blank was the measure of interests. Analysis of variance and Duncan's Multiple Range Test were the statistical procedures employed. The study shows that the interests of students in engineering differ statistically among the curriculum specialties. The study also reveals the nature of these differences. Some practical applications of the data are suggested.

Use of the Detroit tests of learning aptitude with EMR.

Abstract: The preliminary Orientation and Mobility Test Battery (OMTB) was written from a list of 90 skills relevant to program goals. The subtests cover a broad range of orientation, mobility, and living skills. Each subject was used as his own control in a one group preand posttest design. The children achieved significant increments in performance on four living skills tests (p< .05)-hanging a coat on a hanger, pouring liquid, setting a table, and lighting a stove-and on one orientation mobility test (p< .01 )-squaring off. (Squaring off is an orientation mobility skill requiring knowledge of the relative position of two objects. When squaring off, one aligns and orients himself with one of the objects, and then uses the information obtained to walk to the other objecr.) Staff members were in close agreement when ranking for proficiency (W=.89; p< .001) and improvement (W=.40; p< .01) in orientation and living skills. The staff's proficiency ranks were correlated with 12 of the 21 OMTB posttests (p<.10 to p< .001) indicating a significant relationship between the order in which staff ranked subjects for proficiency and the order in which subjects ranked in performance on each of the 12 posttests. Staff gave orientation, mobility, and living skills about equal weight when ranking subjects for proficiency. The staff's ranks for improvement were significantly correlated (p<.10 and p< .05) with three of the OMTB posttests. Thus, there was little relationship between staff's ranks for improvement and distributions of differences obtained from preand posttest scores. The feasibility of developing a performance battery of orientation, mobility, and living skill tests was demonstrated. The OMTB is offered as a heuristic provisional instrument to interested researchers; it is not to be employed as though it were a fully standardized test battery.

A continuous culture device for protozoan cells.

Abstract: SYNOPSIS. A continuous culture device suitable for controlled growth of Euglna gracilis is described. It could probably be adapted to other similar cell types with generation times no greater than 150–200 hrs.

Multiple-item exposure and serial learning.

Abstract: Summary.-Recent studies show that simultaneously-presented pairs detrimentally affect paired-associate learning. In this study, serial learning was nor affected by exposure of the cue item plus 1, 2 or 3 preceding items. The data seem relevant to the issue regarding identity of a functional stimulus; additional research of a parametric nature is in order. In a typical serial learning of CVC trigrams by the anticipation method, successive items appear one at a time. The question arose whether exposure of multiple items might provide for implicit rehearsal of exposed subsets and so aid learning. Interest in the effects of multiple-item exposure has recently appeared but so far has been limited to the learning of paired-associates (Brown & Brown, 1965; Brown & Read, 1966). The general finding is that exposure of subsets of paired-associates appears to have a detrimental effect. Brown & Read (1966) suggested some possible souces of difficulty, one of which might stem from serial-position cues generated by the use of invariant subsets. To the extent that such cues are integral to serial learning, it was predicted that multiple-item exposure should favor forming of serial associations since it structures the material for intratrial rehearsal. Method.-Forty student \olunteers from the general psychology course at the University of Maine served as Ss. None had had prior experience in serial learning and all were naive with respect to the purpose of the study. Twelve typewritten CVC rrigrams (Archer, 19GO), with an average association value of 36.5%, were presented serially by means of a Gerbrands Model M1-A memory drum. The order of items was MEP, JID, GAH, NUC, ZOG, KEX, VAK, QUM, PIB, CEV. YOT, RYL. A syllable-presenration rate of 2 sec. with an intertrial interval of 6 sec. was used. The symbol XXX signaled the beginning of each trial. For purposes of the srudy, the drum aperture was replaced by one of four cardboard masks that permitted, respectively, the viewing of from one to four trigrams simultaneously. Ten Ss were randomly assigned to each of four groups that differed only in terms of the number of trigrams exposed ar any one time. The control group (C) saw only the current stimulus item while experimental groups (E-1, E-2, E-3) saw the stimulus item #lus one, two or three preceding trigrams. All Ss were instructed to anticipate and pronounce each item before it appeared. Anticipation was emphasized and nothing was said concerning the presence of more than a single item in the viewing aperture. In other words, rehearsal of doublets, triplets, erc. was neither encouraged nor discouraged. Results.-Table 1 shows mean trials to criterion (two successive errorless trials) and other summary data. By inspection, and by the analysis of variance (F .30), and the Kruskal-Wallis test which compares the sample distributions (H = 0.28, df = 3, p > .95), the data clearly were not significant. Inspection of serial-position curves, plotted for the various groups, also supported the general finding that performance did not differ as a function of