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- ItemStudies on the Root Growth of Willow Cuttings at Controlled Temperatures(1931) Baker, Henry H.; Cell Biology & Molecular Genetics; Digital Repository at the University of Maryland; University of Maryland (College Park, Md)
- ItemAn Historical and Critical Development of the Theory of Legendre Polynomials Before 1900(1938) Laden, Hyman N.; Lancaster, O.E.; Mathematics; Digital Repository at the University of Maryland; University of Maryland (College Park, Md)
- ItemThe Biology, Nutrition and Control of Formica exsectoides Forel(1945) Haviland, Elizabeth Edge; Biology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md)
- ItemDie Balz des Kolibris Selasphorus platycercus(Zoologische Jahrbücher. Abteilung für Systematic, Ökologie, und Geographie der Tiere, 1948) Wagner, H. O.; Inouye, David W.This article describes behavior of Broad-tailed Hummingbirds (Selasphorus platycercus) in Mexico, which the author describes (perhaps mistakenly) as mating behavior.
- ItemTHE REACTION OF THE MONO ETHYL ENOL ETHER OF DIHYDRORESORCINOL WITH o-, m- AND p-TOLYLMAGNESIUM BROMIDES(1949) Van Artsdale, Anna Lee; Chemistry; University of Maryland (College Park); Digital Repository at the University of Maryland
- ItemThe Feeding Habits of the Toadfish (Opsanus Tau) Based on an Analysis of the Contents of the Stomach and Intestine(1951) Chrobot, Raymond J.; Littleford, Robert A.; Biology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md)Opsanus tau, (Linneaus) - the toadfish, inhabits a vast area along the Eastern Sea Coast of North America. It is found from the coast of Maine to the regions of the West Indies. North of Cape Cod, its occurrence is rather rare. As for the Chesapeake localities, according to previous records the toadfish lives in the muddy bottoms of the oyster regions of the Chesapeake Bay, around the mouth of the Potomac River, and elsewhere in the saltwater regions. Many specimens were collected from many localities around Annapolis, Maryland to the entrance of the Bay by Hildebrand and Schroeder (1927). Studies on the feeding habits of the toadfish have not been very extensive over the past years as reviewed in the literature. Little attention has been given to very detailed analyses of this type because of their lack of economic importance. (Hildebrand and Schroeder, 1927) in their mention of the toadfish state that its principal food appears to consist of crustaceans, with a combination of mollusks, or other fish. Small crabs among the crustaceans appeared most frequently in the food, although shrimp (and in the smaller individuals Amphipods) and Isopods also were present. Almost any kind of offal is eaten, and in places where garbage is thrown overboard, toadfish are almost always present in comparatively large numbers. (Linton, 1901) noted that the alimentary canal is chiefly filled with crustacean and molluscan remains and the bones and scales of fishes. He also noted finding a partly digested toadfish in the stomach of another. (Gudger, 1908) stated that their favorite food is young molting blue crab; any crustacean will do, however, or fish or almost any kind of offal. This investigation was concerned with the feeding habits of Opsanus tau in the Chesapeake Bay in the vicinity of Crisfield, Maryland. A somewhat detailed analysis was made in the determination of the specific type of food that was present in the comparison to what has previously been noted. In correlation with previous accounts of notations made on the feeding habits of the toadfish , a definite relation occurred between the analyses presented here with earlier findings.
- ItemA Study of the Ixodid Ticks of Northern Florida, Including the Biology and Life History of Ixodes scapularis Say (Ixodidae: Acarina)(1953) Rogers, Andrew J.; Cory, Ernest N.; Entomology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md)
- ItemThe Influence of Calcium on the Distribution of the Ring-Necked Pheasant (Phasianus colchicus) in North America(1954) Dale, Frederick Harold; Littleford, Robert A.; Digital Repository at the University of Maryland; University of Maryland (College Park, Md)
- ItemOn the Biology and Control of the North American Chestnut Weevils(1956) Johnson, Warren T.; Cory, E.N.; Entomology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md)Curculio auriger (Casey) and Curculio proboscideus Fab. are indigenous North American nut weevils and attack only the fruits of chestnut and chinquapin. Their natural distribution occurs over the same geographical areas that the American chestnut was found. Since the destruction of most of the native chestnut trees by chestnut blight, Endothia parasitica (Murr.), the weevils have been able to survive on scattered plantings of oriental chestnuts which are resistant to blight, from a few native chestnut trees partially resistant and from the coppice growth of old chestnut stumps. Rearing of both species in the field was accomplished by the use of soil cages set into the ground to a depth of 12 inches. Adult behavior was studied in large cages that completely covered the tree. Chestnut weevils lay their eggs in the kernel. The eggs of C. auriger hatch in about eight days and those of C. proboscideus hatch in about 10 days under the conditions in central Maryland. There are four larval instars in each species and these are described and illustrated. Head characters were found that will separate the species and the instars. C. auriger completes its larval development in 21 days while it takes 30 days for Q. proboscideus. The pupae of both species are of' the exerate type and may be separated by the presence of two small bristles on the beak, near the insertion of the antennae, of C. auriger. These bristles are lacking in C. proboscideus. The usual life cycle of C. auriger is two years. The life cycle of C. proboscideus is usually one year. A few individuals of each species require an additional year to complete their cycle. The adult C. auriger issues from the ground in May and feeds on the chestnut catkins. After the catkins wither they disperse and are not seen again until the chestnuts are nearing maturity. C. proboscideus issues from the ground late in July and may be seen in the trees a few days after emergence. The male genitalia were studied for taxonomic characters. These characters are sufficiently clear so that the two chestnut weevils may be identified thereby. Two species of internal insect parasites were found. Myiophasia nigrifrons Tns., a tachinid fly, was reared from the larvae of both species of' chestnut weevils and was observed in its larval stage within the body cavity of the chestnut weevil larva. Urosigalphus armatus Ashm. is a braconid parasite and was found only in the larvae of Q. prohoscideus. Chemical control studies have shown that the adult stage is the most susceptible to insecticides. Preliminary tests with heptachlor, applied at the rate of six to eight pounds of the chemical per acre, as a spray or dust to the ground cover under the trees, have given excellent results for the control of chestnut weevils.
- ItemEcological Studies of Black Flies in Two Maryland Counties (Diptera:Simuliidae)(1957) McComb, William E.; Bickley, William E.; Entomology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md)
- ItemHeats of Combustion and Formation of Some Simple Aliphatic Amines(1958) Jaffe, Irving; Chemistry; Digital Repository at the University of Maryland; University of Maryland (College Park, MD)
- ItemSonic Limit Singularities in the Hodograph Method(1958) Schot, Steven H.; Ludford, Geoffrey S.S.; Mathematics; Digital Repository at the University of Maryland; University of Maryland (College Park, Md)In the hodograph transformation, introduced to linerize the equations governing the two-dimensional inviscid potential flow of a compressible fluid, there may appear so-called limit-points and limit-lines at which the Jacobian J = ∂(x,y)/ ∂(q,θ) of the transformation vanishes. This thesis investigate these singularities when they occur at points or segments of arc of the sonic line (Mach number unity). Assuming the streamfunction to be regular in the hodograph variables, it is show that sonic limit points cannot be isolated but must lie on a supersonic limit line or form a sonic limit line [cf. H. Geiringer, Math. Zeitschr., 63, (1956), 514-524]. Using this dichotomy a classification of sonic limit points is set up and certain geometrical properties of the mapping in the neighborhood of the singularity are discussed. In particular the general sonic limit line is shown to be an equipotential and an isovel; an envelope of both families of characteristics; and the locus of cusps of the streamlines and the isoclines. Flows containing sonic limit lines may be constructed by forming suitable linear combinations of the Chaplygin product solutions for any value of the separation constant n ≥ 0. For n less than a certain value n0 and greater than zero (n = 0 corresponds to the well-known radial flow), these flows represent a compressible analogue of the incompressible corner flows and may be envisaged as taking place on a quadruply-sheeted surface. The sheets are joined at a super-sonic limit line and at the sonic limit line which has the shape of a hypocycloid (n >1), cycloid (n = 1), or epicycloid (n <1). To exemplify the general behavior, the flows are constructed explicitly for n = 1/2, 1, and 2. The shape of the sonic limit line is also discussed when solutions corresponding to different n are superposed, and it is shown how then the supersonic limit line can be eliminated so that an isolated sonic limit line is obtained. A flow containing such an isolated sonic limit line is presented. An appendix derives the asymptotic solution for large values of n which corresponds to the sonic limit solution. The above results have been published in part in Math. Zeitschr., 67, (1957), 229-237. Other portions of this thesis will appear in two papers in Archive Rational Mech. and Anal., 2, (1958).
- ItemA COMBINATORIAL REPRESENTATION FOR ORIENTED POLYHEDRAL SURFACES(1960) Edmonds, John Robert Jr; Reinhart, Bruce; Mathematics; Digital Repository at the University of Maryland; University of Maryland (College Park, Md)
- ItemThe Effect of Plant Nutrition on the Reproductive Rate and Susceptibility to Malathion of Two Strains of the Two-Spotted Spider Mite, Tetranychus telarius (L.)(1960) Henneberry, Thomas J.; Bickley, William E.; Entomology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md)Studies were conducted to determine the effect of plant nutrition on the reproductive rate and susceptibility to malathion of two strains of the two-spotted spider mite. The two strains of mites used as test organisms are characterized by their widely different levels of susceptibility to phosphate acaricides. Lima bean plants were grown in quartz sand and supplied nutrient solutions containing varying levels of nitrogen, phosphorus and potassium. Total nitrogen and total water soluble carbohydrate in the host plant tissue were determined by standard methods. Correlation analysis with the number of mite progeny and results of leaf analyses were conducted. The effects of plant nutrition on susceptibility to malathion of the two mite strains were determined by comparing per cent mortality data of mites from plants supplied the various nutrient solutions, Dosage-mortality responses of the two mite strains were also determined for mites of both strains from plants supplied nutrient solutions producing the greatest response in susceptibility. The reproductive rate of both strains increased as the supply and absorption of nitrogen increased. However, in studies with the resistant mite, a reduction in the number of progeny occurred on plants supplied the highest nitrogen level. The number of progeny of the malathion nonresistant mite were significantly correlated to increased nitrogen absorption. Increased reproductive rate of both strains was correlated to the carbohydrate present in the leaf tissue. When carbohydrate content in the leaf tissue was increased along with an increase in nitrogen supply and absorption the mite reproductive rate also increased. At still higher levels of nitrogen supply and absorption, carbohydrate content of leaf tissue decreased and the mite reproductive rate was depressed or failed to increase, The malathion non-resistant mite appeared more responsive to plants deficient in nitrogen than the resistant mite, On plants supplied the low nitrogen nutrient solutions, non-resistant mites failed to subsist, while the resistant mites maintained relatively high populations. The malathion non-resistant mite also produced more progeny on plants when phosphorus supply was increased. Populations of the resistant mite increased at higher levels of potassium. Phosphorus and potassium supply alone and in combination with certain levels of nitrogen affected nitrogen absorption and the relative amounts of carbohydrate present in the leaf tissue. Increasing the nitrogen supply to host plants resulted in increased susceptibility of the resistant mite to malathion. The non-resistant mite was more responsive to variations in phosphorus supply of host plants. A decrease in susceptibility followed an increase in phosphorus supply.
- ItemThe Genera Hemiberlesia and Abgrallaspis in North America with Emphasis on Host Relationships in the H. Howard (Cockerell) Complex (Homoptera: Coccoidea: Diaspididae)(1960) Davidson, John Angus Sr.; Bickley, William E.; Entomology; Digital Repository at the University of Maryland; University of Maryland (College Park, MD)The work reported consists of revisionary studies of Hemiberlesia Cockerell 1897 and Abgrallaspis Balachowsky 1948 in North America. The interpretation of North America is that of Ferris (1937), "all the mainland from the Arctic regions to and including the Panama Canal Zone." According to Ferris (1942), Hemiberlesia contained 15 species. As a result of this study, only eight of these species are here referred to Hemiberlesia. They are: rapax (Comstock), lataniae (Signoret), popularum (Marlatt), ignobilis Ferris, cupressi (Cockerell), diffinis (Newstead), candidula (Cockerell), and palmae (Cockerell). The species H. coniferarum (Cockerell) is newly assigned having previously been placed in Diaspidiotus Berlese and Leonardi, by Ferris. A tenth species, H. pseudorapax McKenzie, was assigned to this genus by its author. Seven of the 15 species have been assigned to Abgrallaspis. Both these genera appear to be North American in origin. Abgrallaspis was originally created for six species. Three of these occur in North America and were transferred from Hemiberlesia by Balachowsky. They are: palmae (Cockerell), degeneratus (Leonardi), and cyanophylli (Signoret). The last named species was designated as the genotype. Balachowsky (1953) later reassigned palmae to Hemiberlesia and transferred four more North American Hemiberlesia species to Abgrallaspis, namely, howardi (Cockerell), comstocki (Johnson), coloratus (Cockerell), and fraxini (McKenzie). A study of these species in the National Coccoid Collection revealed a complex centering about A. howardi as conceived by Ferris (1938). Usual morphological comparisons of slide mounted adult females failed to yield results, therefore, host transfer experiments were undertaken. A population of "howardi" of Ferris was secured on pachysandra. A total of 2,700 individual crawler transfers were then made to 20 different host plants. These hosts had been chosen because a preliminary study indicated unusual character variation in specimens collected from them. Fourteen of the test hosts (largely ornamentals) were later found to be infested with 14 to 54 per cent of the transferred crawlers. These crawlers were allowed to mature. Adult females were then collected and mounted for study. Six host plant species were completely unacceptable to infestation by the transferred crawlers. Five of these were plum, pear, peach, apple, and pine. A. howardi was described from plum in Colorado, and later recorded from such hosts as pear, peach, and apple. A study of the species Ferris synonymized with A. howardi revealed the test population to be A. townsendi (Cockerell), which was described from an unknown host in Mexico, and later recorded from a long list of ornamentals primarily in the southern and eastern United States. This species is redescribed and the name revalidated. A table is presented showing the variations found in salient taxonomic characters of A. townsendi collected from 14 different experimental host plants. Important variations in the size of the second lobes of A. townsendi were recorded. Second lobe reduction from three-fourths the length of the median lobes to mere hyaline points was observed. Specimens in the last category strongly resemble Diaspidiotus ancylus (Putnam). Aside from these second lobe variations, A. townsendi is a relatively stable species from the standpoint of host determined morphological variables. Avocado was the sixth test host on which transferred crawlers would not develop. Long series of scales from this host are present in the National Collection. They were collected from avocado fruit in quarantine at Texas, from Mexico. This species, A. perseus Davidson, is described as new herein. As here understood for North America, Abgrallaspis contains 13 species. Six were placed in this genus by Balachowsky, and seven by the writer. The last are: flabellata (Ferris) from Hemiberlesia; quercicola (Ferris) from Hemiberlesia; mendax (McKenzie) from Hemiberlesia; oxycoccus (Woglum) from Aspidaspis Ferris; ithacae (Ferris) from Aspidaspis; perseus Davidson as a new species; and townsendi (Cockerell) as a revalidated name. A brief presentation of materials and methods utilized in the host transfer experiments is followed by a discussion of the structural characters used in this work. Descriptions of Hemiberlesia and Abgrallaspis are accompanied by keys and descriptions to all the species in North America. Figures of adult female pygidial characters and scale coverings are provided for all species considered in these two genera.
- ItemOn Numerical Analysis in Residue Number Systems(1964) Lindamood, George Edward; Rheinboldt, Werner C.; Computer Science Center; Digital Repository at the University of Maryland; University of Maryland (College Park, Md)Recent attempts to utilize residue number systems in digital computers have raised numerous questions about adapting the techniques of numerical analysis to residue number systems. Among these questions are the fundamental problems of how to compare the magnitudes of two numbers, how to detect additive and multiplicative overflow, and how to divide in residue number systems. These three problems are treated in separate chapters of this thesis and methods are developed therein whereby magnitude comparison, overflow detection, and division can be performed in residue number systems. In an additional chapter, the division method is extended to provide an algorithm for the direct approximation of square roots in residue number systems. Numerous examples are provided illustrating the nature of the problems considered and showing the use of the solutions presented in practical computations. In a final chapter are presented the results of extensive trial calculations for which a conventional digital computer was programmed to simulate the use of the division and square root algorithms in approximating quotients and square roots in residue number systems. These results indicate that, in practice, these division and square root algorithms usually converge to the quotient or square root somewhat faster than is suggested by the theory.
- ItemStudies on the Physiology of Hemolymph Coagulation in Perioplaneta Americana (L.)(1964) Wheeler, Ronald Earl; Jones, Jack Colvard; Entomology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md)In the cockroach, Periplaneta americana (L.), hemolymph coagulation (a) is inhibited for as long as 30 minut es at 0° to 4°c, (b) is initiated at 5°c, (c) is permanently inhibited at 60°c, and (d) takes place in 6 distinct stages. Hemocyte agglutination and transformation is inhibited at 0° to 4°C, is permanently prevented at 55°c, and is independent of plasmal factors. Live plasmatocytes, granular hemocytes, and cystocytes are structurally identical, but differ functionally in their capacity to phagocytize and in their fragility. The cystocyte's primary function is the initiation of coagulation and/or precipitation of the plasma by ejecting cytoplasmic material, including mitochondria, into the surrounding plasma. Hemocyte-free plasma will not spontaneously precipitate, but requires either ionic calcium released from transforming hemocytes, and/or material from exploded cystocyte mitochondria . Substances inside mitochondria may well be t he source of a coagulation-inducing substance that initiates plasma precipitation and veil formation. Substances involved in P. americana coagulation are present in the plasma of 9 other species of cockroach which react to P. americana cystocytes. Substances in the plasma of Tenebrio molitor, Galleria mellonella, or Rhodnius prolixus do not precipitate in the presence of P. americana cystocytes. The amount and/or effectiveness of a coagulation-inducing substance released from cystocytes presumably determines the degree of plasma precipitation. Physiologically active substances contained in and/or released from the corpora allata and c. cardiaca, but lacking in the brain, may regulate the percentage of circulating cystocytes, thereby influencing the coagulability of the hemolymph.
- ItemCompletions(1964) Nielsen, Robert Maurice; Brace, John W.; Mathematics; Digital Repository at the University of Maryland; University of Maryland (College Park, Md)This paper presents a new approach to the theory of completions. The treatment is based on the concept of convergence on filters and related topologies. For a given uniform Hausdorff space Xu and a collection S of Cauchy filters in Xu, the basic result is the construction of a uniform Hausdorff space. Xu having the properties that Xu is isomorphic to a dense subspace of Xu and every filter in S converges to a point in S. As a special case, the completion of Xu of Xu is obtained. The construction is so given as to prove the existence of the space Xu. The technique involves embedding the object X to be "completed" in a space of functions F which has as its domain a space of continuous functions C(X) defined on X. The procedure is analogous to the process of taking the bidual E" of a locally convex topological vector space. Indeed, E" is obtained as a special case. In the absence of sufficient structure on X, the Xu is obtained as the closure of X in F. In a locally convex space or an abelian topological group having enough character to separate points, Xu is obtained as a bidual or a second character group of the object X.
- ItemThe Effect of Changes in Structure of the Reactants on the Rate of Enamine Formation(1964) Marchese, James Salvatore; Pratt, Ernest F.; Chemistry & Biochemistry; Digital Repository at the University of Maryland; University of Maryland (College Park, Md)It has been found that the rate of formation of a wide variety of enamines can be accurately determined by observing the rate at which the by-product water collects in a Dean-Stark trap. On the basis of the results observed upon varing the reactant ratio, the catalyst concentration and the temperature, 0.125 mole of carbonyl compound, 0.375 mole of amine and .001 mole of p-toluenesulfonic acid dissolved in sufficient benzene to give a total volume of 500 ml. were employed in the standard procedure. The solution of reactants was heated under reflux in an apparatus fitted with a water trap and frequent readings of time and water volume were taken until the reaction was complete. Nearly quantitative (98 to 100%) yields of water were ordinarily obtained and 85 to 100% yields of enamine were usually isolated. As the structure of the carbonyl component was varied an extremely wide range of reaction rates was encountered. The relative reactivity of many of these compounds had not been determined preciously. It was found that the rate decreased markedly among cyclic ketones as the ring was expanded from five to six to seven members and also when the methyl group of methylcylohexanones were shifted from the four to the three to the two position, Steric effects appear to be responsible for these rate differences. Somewhat unexpectedly ∝-tetralone did not react while β-tetralone reacted smoothly. Although the literature contains very little information on the formation of enamines of diketones a number of these were converted to the mono-enamines very smoothly. The rate decreased in the sequence, 1, 3-cyclohexanedione, dimedone, acetylacetone, benzoylacetone and 2-acetylcyclopentanone. Some evidence that ketones having planar structures reacted faster than those with non-planar structures was found, but no obvious correlation between degree of enolization and rate of reaction was observed. The reaction of acetophenones was much improved when the reaction temperature was changed from 82° to 112° by using toluene as a solvent. As the electron attracting ability of the para substitute was inreased in the order, CH3, H, Cl and N02 the rate consistently increased. Phenylacetone reacted smoothly under the standard conditions, but heptanone-2 gave only a 27% yield of water in five days . The importance of steric factors is emphasized by the fact that cyclohexanone gave a 98% yield of water in two hours. Typical aliphatic aldehydes reacted so rapidly that in order to increase the accuracy of t;he rate measurements 0.000125 mole of catalyst was used in place of the standard 0.001 mole. The order of decreasing rate was phenylacetaldehyde, It is apparent that the rate decreasing effect of chain branching at the alpha position diminishes when the branches are joined into a ring. The results for phenylacetaldehyde and phenylacetone indicated that aldehydes react over one thousand times as fast as ketones. The rate of formation of enamines from cyclohexanone and a variety of amines was also determined under the standard conditions. Shifting a methyl group on the piperidine ring from the four to the three to the two position greatly decreased the rate and pyrrolidine reacted faster than both piperidine the and hexamethylene imine. Morpholine and especially N methylpiperazine reacted much faster than piperidine while n-butylmethylamine reacted most slowly of all the amines mentioned. In only a few special cases was integral order kinetics obtained. The results can, however, be quite well correlated with a straightforward mechanism if it is assumed that both the step in which the amine adds to the carbonyl group and the step in which this addition product is dehydrated ordinarily affect the overall rate.