Showing papers by "University of Maine published in 1980"

Feeding and nutritional ecology of the sea urchin strongylocentrotus drobachiensis in Maine, USA

Abstract: The sea urchin strongylocentrotus drobachiensis exhibited a high degree of food selectivity, whether foods were presented singly or in combination. Foods ranked from most to least preferred were, in summer, Laminaria longicruris, Chondrus crispus, Corallina officinalis, Ascophyllum nodosum, and Agarum cribrosum, whereas in winter A. nodosum and A. cribrosum exchanged ranks. Food preference was not correlated with caloric content but, because of higher feeding rates on preferred foods, caloric intake was positively correlated with preference. Similarly, food absorption rankings were not correlated with food preference, with the exception of gravimetric efficiencies in winter. However, the absorption of L. longicruris, the most preferred alga, was highest in all measurements. Growth and reproductive development of S. drobachiensis on single species diets were positively correlated with food preference. Highest values occurred with animals fed L. longicruris. Urchins transferred from non-preferred to preferred diets showed increased somatic and reproductive growth compared to control animals on the original, non-preferred diets. Conversely, when transferred from preferred to non-preferred diets, urchins showed reduced growth compared to controls. No combination diet tested supported significantly better gonadal growth than L. longicruris: 25% C. crispus supported slightly better somatic growth than L. longicruris alone. These data support the view that S. drobachiensis has evolved a feeding strategy resulting in the maximization of growth and reproduction.

The Myth of Left-Wing Authoritarianism

Abstract: The authors of The Authoritarian Personality (Adorno, et al., 1950), armed with the modern tools of psychoanalysis as well as ancient knowledge of scapegoating, reported an extensive series of investigations into the psychological roots of fascism. The book's basic thesis was that antisemitism and prejudice toward outgoups, collectively designated ethnocentrism, is basic to the fascism-prone personality. Further, the authors believed that a multifaceted approach, based upon psychoanalytic understandings of personality, could

Buffering of silica and phosphate in a turbid river1

Abstract: The buffering of riverine dissolved silica and phosphate by sorption reactions between the aqueous phase and suspended secliment is examined with the turbid Colorado River system as a model. Concentrations are found to lie in a range predicted from laboratory sorption experiments with natural sediments and waters. Phosphate is probably highly buffered by suspended sediment during river flow while silica is not. Silica appreciably affects phosphate sorption reactions but not vice versa. Increased temperature results in higher silica but lower phosphate concentrations as a result of sorption. The buffering action of suspended sediments is largely complete within a few hours and is approximately proportional to the concentration of suspended sediment. Of prime concern in the study of nutrient dynamics in natural waters are the factors governing the availability of various nutrients to biotic uptake. This availability is often related to the concentrations of nutrients, which in certain systems are strongly affected by chemical interplay between their dissolved forms and mineral surfaces. Adsorption/desorption reactions involving common soil and sediment materials can exert a strong influence on the partitioning of silica and phosphate between solid and aqueous phases in periods of hours to days (e.g. Edzwald et al. 1976; Kennedy 1971). Such rapid partitioning could exert significant influence on the nutrient flux through a river system with high concentrations of suspended materials. The presence of labile silica and phosphate sorption sites on the suspended sediment should therefore provide a buffer capacity for the dissolved forms of these species. Our study focuses on the turbid Colorado River system above present-day 1 This work was supported in part by grants NSFRANN AEN 72-03469 AO3 and GI-34831 Al. z Present address: New York Cooperative Fishery Unit, Department of Natural Resources, Fernow Hall, Cornell University, Ithaca, New York 14853. Lake Powell (Fig. 1). The reservoir (occupying about 300 km of the former Colorado River) was formed by Glen Canyon Dam in 1963. Most of the water delivered to this region derives from snowmelt in the mountains of Colorado and Wyoming during spring runoff. The seasonal variation of flow has been partially damped by the construction of reservoirs upstream of Lake Powell in the early 1960s. Historically, average water flows through this region are of the order of 1-2~ lOlo rn”. yr-I. Suspended sediment concentrations in the Colorado River system commonly reach several thousand milligrams per liter. The bulk of the sediment load in the system originates in the Colorado Plateau rather than in the mountains from which the water comes (Iorns et al. 1965). The suspended sediment consists primarily of illite, kaolinite, smectite, quartz, feldspar, calcite, and dolomite, reflecting the largely Mesozoic sedimentary rocks which are their provenance (Mayer 1973; Kennedy 1965). Evidence for the buffering of silica in river systems has been summarized by Edwards and Liss (1973). That this phenomenon has occurred in the Colorado River is shown in Fig. 2, in which weighted mean annual concentrations of silica and chloride in the Colorado River

Relationships between effects of environmental temperature and seston on growth and mortality of Mytilus edulis in a temperate northern estuary.

Abstract: The growth and mortality of experimentally-rafted Mytilus edulis L. of known age at 7 locations in a northern estuary (Damariscotta River, Maine, USA) were related to environmental temperatures and to the presence or absence of various potential food sources. All particles were regarded as potential food substrates. Growth decreased appreciably at sites where water temperatures exceeded 20°C, but mussels survived a wide range of elevated temperature exposures, ranging from 0 to 149 degree-days in excess of 20°C. The maximum temperature was 25°C. Mortalities of mussels at all sites but did affect the extent of mortality, which increased abruptly in late summer, when water temperatures were declining. Differences in degree-days of exposure to elevated temperatures did not influence the timing of mortality, which occurred synchronously at all times, but did affect the extent of mortality, which ranged from 35 to 90%. The period of high mortality was preceded by a rapid decline in phytoplankton standing crop. Total particle concentrations decreased during this period, but the shift toward larger particles suggests that there was little, if any, decrease in total volume of material in the seston, at least through August. It is suggested that living phytoplankton provided the critical energy source for these mussels, and that the mortalities were caused by rapidly reduced ration at a time of metabolic stress. The role of temperature and the possible role of the gametogenic cycle are discussed. In addition, the feeding efficiency of M. edulis may have decreased during this period due to an increase in mean particle diameter. Chlorophyll was divided into a nannoplankton fraction ( 20 μm). A smaller size criterion for this distinction is proposed for future studies. The importance of nannoplankton to the primary production of this estuary and the role of nannoplankton and nannoplankton-sized particles in the diet of mussels in nature are discussed.

Growth of CuInSe2 by molecular beam epitaxy

Abstract: We have used molecular beam epitaxy to grow CuInSe2 layers on CdS (0001B) and other substrates. Epitaxial growth is obtained at a substrate temperature of 300 °C. The ratio of the arrival rates of copper to indium is the key parameter governing layer stoichiometry. In order to produce low‐resistivity p‐type layers, the Cu/In arrival rate ratio must be slightly higher than that used to grow nominally stoichiometric layers. This suggests that a different defect is controlling electrical properties, rather than the copper vacancy complex which dominates bulk material. We have fabricated CuInSe2/CdS heterojunctions which show a maximum solar conversion efficiency of ∼5%.

North Atlantic oceanography as possible cause of Antarctic glaciation and eutrophication

Abstract: Tarling1 suggested that ice ages may occur when continental blocks occupy polar positions, isolating the pole from oceanic influences, and when nearby seas are available to provide moisture for the build-up and maintenance of polar ice caps. Such conditions gradually became established in the Southern Hemisphere where the present ice age began 13 Myr ago2. The Cenozoic circum-Antarctic geographic and oceanographic evolution has been recently summarised by Kennett3. I report here that circum-Antarctic palaeogeography and palaeoceanography alone were insufficient to lead to the Antarctic glaciation. A model is presented that suggests that the final triggering events took place in the North Atlantic.

Temporal discrimination and a free-operant psychophysical procedure

Abstract: Pigeons were presented a series of keylight time periods (separated by blackouts) during which two response keys were lit, one by blue light and the other either by orange or green. Blue-key responses changed the color on the other key. Orange-key responses sometimes produced food during the first half of a time period; green-key responses sometimes produced food during the second half. In three experiments, the probability of a green-key response increased as a function of elapsed time. Experiment 1 compared performance when the duration of the keylight periods was varied across a wide range. Discrimination of performance was similar across the range of durations. Experiment 2 varied both relative reinforcement rate and the local reinforcement rate for orange-key and green-key responses. These manipulations produced changes in response bias but not discrimination sensitivity. Experiment 3 varied the local temporal placement of reinforcers within time periods and demonstrated that choice behavior was affected by differential reinforcement at different points during the time periods. The results were consistent with previous research on duration discrimination that used psychophysical trials procedures.

Swimming performance of European eel (Anguilla anguilla (L.)) elvers

Abstract: To determine the relation between swimming endurance time and burst swimming speed, elvers of the European eel, Anguilla anguilla (L.), were made to swim at speeds from 3.6 to 7.2 L (body lengths) s−1 in both fresh and sea water. Swimming endurance time of elvers averaging 7.2 cm total length decreased logarithmically with increased swimming speed from 3.0 min at 3.5 L s−1 to 0.7 min at 5.0 L s−1, and again logarithmically but with a lesser slope to 0.27 min at 7.5 L s−1. No differences were found between fresh and sea water elvers. In still water, elvers could swim at high speeds for about 10–45m before exhaustion, depending upon speed. Elvers would be able to make virtually no progress against water currents >50 cm s−1. Drift in coastal water currents and selective tidal transport probably involve swimming speeds below those tested in this study. Migration into freshwater streams undoubtedly involves avoidance of free stream speeds and a combination of burst and sustained swimming.

Advective control of nutrient dynamics in the epilimnion of a large reservoir1

Abstract: Silica, nitrate, total and dissolved phosphorus, and conductivity were measured during spring and summer in Lake Powell, Utah-Arizona. Phytoplankton productivity was also detcrmined. Conductivity is used as ;L tracer for delineating the advective influence of inflows from the Colorado and San Jtlan Rivers on nutrient d&very and distribution in the reservoir. High spring runoff (l,OOO-2,000 m3*s-l) enters the lake essentially as an overflow and dominates the nutrient cycle in the epilimnion. The interaction of advective nutrient d&very and high turbidity controls the distribution of phytoplankton productivity and nutrient depletion.

Male mating discrimination in drosophila melanogaster, d. simulans and their hybrids.

Abstract: Little is known about the relative importance of the sexes in maintaining reproductive isolation between closely related species in Drosophila. A great deal of evidence demonstrating the importance of females in sexual selection in Drosophila has been amassed, but this work concerns only intraspecific courtship and copulation (Petit and Ehrman, 1969; Spiess, 1970; Ehrman, 1972). The picture regarding interspecific courtship is not clear. It may be that the female determines whether or not copulation will occur between closely related species to the same extent as she does within her own species (Merrell, 1954). However, it may be that males can discriminate well, and do not court interspecifically as readily or persistently as they do intraspecifically. If this is the case, males would exert primary control over the maintenance of ethological isolating barriers, regardless of the female's discriminatory abilities, since the male initiates courtship and copulation. Spieth (1974) has argued that in Drosophila it is indeed the male that is primarily responsible for sexual isolation in nature. One of the best ways to determine whether or not a male has an important role in maintaining ethological isolating barriers is actually to observe and measure interspecific courtship. Direct observation experiments using the Drosophila melanogaster group of species has added support to Spieth's position. Von Schilcher and Dow (1977) found that male Drosophila melanogaster and Drosophila simulans do not court females of their sibling species as persistently or intensely as their own and that it is the males who most often terminate interspecific courtship, while it is the females who usually cause the termination of intrasDecific courtshiD. Manning (1959), working with D. melanogaster and D. simulans, also found a reluctance on the part of males to court interspecifically, but in addition, he found that this reluctance was stronger in D. simulans. Von Schilcher and Dow (1977) did not find such a difference between the species. Both Manning (1959) and von Schilcher and Dow (1977) looked only at pair matings. To date, no one has reported if males in the D. melanogaster species group discriminate to the same extent when both conspecific females and females from a closely related species are present, a situation that is presumably the more natural and meaningful one. Also, mating discrimination in the male hybrids of D. melanogaster and D. simulans has not been studied extensively. Von Schilcher and Manning (1975) measured mating speed and certain parameters of the wing vibration of hybrids, but they did not analyze their discriminatory abilities. Possibly an analysis of the discrimination shown by hybrids will give some clue to the genetic basis of male discrimination in the parent species. The purpose of this study, then, was to examine the abilities of male D. melanogaster, D. simulans and their hybrids to discriminate between conspecific and nonconspecific females in "no choice" pair matings and "male choice" situations to evaluate both the probable importance of the male sex in maintaining ethological isolating barriers and the genetic basis of these abilities.

Feeding assemblages of mammals at fruiting Dipteryx panamensis (Papilionaceae) trees in Panama: seed predation, dispersal, and parasitism

Abstract: Fruiting almendro trees, Dipteryx panamensis, are visited by sixteen species of mammals that eat the fruits exocarp or seed. Seeds are susceptible to predation by granivorous rodents and peccaries. Most mammals that visit Dipteryx trees act as commensals·, eating only the fleshy exocarp and dropping the endocarp with its enclosed seed below the parent tree. So me primates, tayras, coatis, and kinkajous occasionally disperse Dipteryx seeds, but only Artibeus lituratus, Dasyprocta punctata, and Sciurus granatensis disperse large numbers of seeds. Whether D. punctata or S. granatensis act as seed predators or dispersal agents depends on the behavioral context in which they handle fruits.

Swim bladder volume maintenance related to initial oceanic migratory depth in silver-phase Anguilla rostrata

Abstract: Gas deposition rates in the swim bladders of postmetamorphic (silver) Anguilla rostrata eels are about five times greater than those of premetamorphic (yellow) individuals. This extends the maximum depth at which silver eels can maintain swim bladder volume and prepares them for their spawning migration to the Sargasso Sea.

The structure of the firm and the adoption of process innovations

Abstract: A major body of organizational and management theory indicates that the likelihood of a firm's adopting innovations will vary directly with the firm's complexity and inversely with its centralization and formalization These hypotheses are tested with data from a nationwide survey on the adoption of process innovations The results support each hypothesis The results also indicate that, of the three structural variables, complexity plays the central role in effecting adoption behavior

Enrichment of dissolved phenolic material in the surface microlayer of coastal waters

Abstract: The sea surface microlayer often has greater concentrations of dissolved organic material (DOM) than subsurface water1–5, but the chemical nature of this material remains unresolved. Most studies of microlayer organic chemistry have focused on lipid6–9 and hydrocarbon components10,11. Carbohydrate material can account for a significant fraction of the microlayer DOM4 supporting IR spectroscopic evidence which suggests that the microlayer material is predominantly carbohydrate-proteinaceous complexes12. Some similarity of the microlayer DOM to marine humic material has been noted12–14. We report here preferential enrichment of dissolved phenolic material in the surface microlayer of coastal waters.

Adhesive organs of the gastrotricha

Abstract: The lateral and posterior adhesive organs of an undescribed species ofNeodasys can be seen by electron microscopy to have only one gland cell type. This gland has dense spherical secretion granules like secretion granules of the viscid glands of other gastrotrichs, and it extends to the exterior through a tubular extension of the animal's cuticle, the adhesive tubule, as in other gastrotrichs. Each adhesive gland ofNeodasys has a prominent striated rootlet that extends through its full length, attaching at its distal end to a basal-body-like structure at the tip of the gland's neck. Unlike other gastrotrichs,Neodasys has no second gland type that would be equivalent to a releasing gland. The lateral adhesive organs have a sensory cell closely associated with the gland cell but not in direct communication with the lumen of the tubule; it bears a single cilium that projects alongside the adhesive tubule. The posterior adhesive organ has adhesive gland cells whose necks reach to adhesive tubules on toe-like extensions of the animal's body; sensory cells here are not in a one-to-one association with the tubules; a secretory myoepithelial cell extends to the tip of each toe. The adhesive organs ofNeodasys are interpreted as being of a form that would have been found in a common ancestor to the gastrotrichs and from which the duo-gland organs of other gastrotrichs might have been derived.

Lactate dehydrogenases of Atlantic hagfish: physiological and evolutionary implications of a primitive heart isozyme

Abstract: Isozymes of lactate dehydrogenase from heart and muscle of Atlantic hagfish show less functional divergence than those from other fishes and higher vertebrates. The enzyme from hagfish heart (B4) displays a higher Michaelis constant for pyruvate and lower substrate inhibition at moderate pyruvate concentrations than heart isozymes from other species. These properties support the hypothesis that the ancestral vertebrate lactate dehydrogenase was a muscle (A4)-type enzyme and also suggest a role for the B4 enzyme in the unusual physiology of hagfish cardiac tissue which functions under sustained hypoxic conditions.

Effects of solids and liquid flows on fermentation in continuous cultures. II. Nitrogen partition and efficiency of microbial synthesis.

Abstract: The effects of varying solids retention time (SRT) and liquid dilution rate (D) on N partition and microbial efficiency were studied in vitro with a dual flow continuous culture system. SRT's of 14.3, 22.0 and 29.7 hr and D's of .07, .11 and .15 volumes/hr were used. Ammonia N accounted for 2.69 to 7.30% of total effluent N. Highest values were observed with 29.7-hr SRT at .11 and .15/hr D's, and were associated with a slight decrease in microbial N. Between 1.17 and 2.50 g microbial N were produced per 24 hr, accounting for 31.34 to 50.49% of total effluent N. Daily output of microbial N increased (P less than .05) with increasing D at the lowest SRT but showed little or no change at the 22.0- and 29.7-hr SRT's. Feed bypass N was inversely related to microbial N and accounted for 44.91 to 65.10% of total effluent N. Microbial cell yields per mole ATP (YATP) ranged from 10.40 to 24.41 and tended to increase with decreased SRT more than with increased D, although responses were variable. Efficiency of microbial N synthesis ranged from 15.75 to 23.91 g microbial N/kg digested dry matter (DDM), with trends similar to those seen for YATP.

Chip wood furnace and furnace retrofitting system

Abstract: A furnace system suitable for independent use and for retrofitting conventional central heating oil furnaces to permit controlled continuous and efficient combustion of fragmented wood type fuels. Wood chips or other fuel fragments are trickle fed into a refractory wood type combustion chamber. For retrofitting an oil furnace the oil burner gun is removed. A flame tube adapter couples the wood type fuel combustion chamber into the oil combustion chamber and heat exchanger plenum of the conventional furnace. The oil burner gun of the retrofitted furnace is used to ignite the wood chips or other fuel fragments during start up. A blower establishes forced draft. The furnace system includes automatic controls for sequencing operation of the elements of the retrofitting furnace system. An independent wood chip furnace system is also described.