bluuebunny/crossref_metadata_2025 huggingface dataset:
SCAPHYTOPIUS ACUTUS (SAY), A NEWLY DISCOVERED VECTOR OF CELERY-INFECTING ASTER-YELLOWS VIRUS
Authors: Chiykowski L. N.
Published: August 2008

Scaphytopius acutus (Say) transmitted a celery-infecting strain of aster-yellows virus from infected periwinkle (Vinca rosea L.) and aster (Callistephus chinensis Nees) to periwinkle, aster, and ladino clover (Trifolium repens L.). It acquired the virus during feeds as short as 4 hours, and transmitted it during a 2-hour feeding period. The minimum incubation time for the virus in the insect was between 21 and 26 days. After an acquisition feed of 7 days and an incubation period of at least 30 days, 11 of 21 insects transmitted the virus to separate periwinkle test plants.
PHOTOSYNTHESIS AND METABOLISM IN MARINE ALGAE: IV. THE FATE OF C14-MANNITOL IN FUCUS VESICULOSUS
Authors: Bidwell R. G. S. , Ghosh N. R.
Published: August 2008

C14-mannitol was supplied to fronds of F. vesiculosus, and its conversion into CO2 and other compounds was studied. Only small amounts of the mannitol taken in were metabolized. Mannitol is apparently not an immediate substrate of respiration, but in time it may be converted into some other substances which are. Dilute acid-soluble polysaccharides acquired small amounts of radioactivity, but most of the mannitol which underwent metabolism was eventually converted to residual carbohydrates. It is concluded that mannitol is probably a storage compound rather than an active metabolite.
ECOTYPIC VARIATION IN PHOTOPERIODISM OF TREES WITH SPECIAL REFERENCE TO PINUS RESINOSA AND THUJA OCCIDENTALIS
Authors: Vaartaja O.
Published: August 2008

A certain daylength treatment inhibited the growth of northern seedlings of Pinus resinosa and Thuja occidentalis more than it inhibited southern seedlings of these species. These treatment – seed source interactions were small, but otherwise similar to those found earlier in 29 northern tree species. The smallness of the interaction was caused by the overruling effect of the endogenously determined growth pattern in P. resinosa, and by the lack of large photoperiodic response in T. occidentalis.The broad subject of ecotypic variation in the photoperiodism of trees is discussed. The evolution of dormancy mechanism suggests that photoperiodism should tend to be overruling in the truly northern trees, and the endogenous rhythm in trees from the middle latitudes.
TAXONOMIC STUDIES IN THE GENUS FRAGARIA TYPIFICATION OF FRAGARIA SPECIES KNOWN AT THE TIME OF LINNAEUS
Authors: Staudt G.
Published: August 2008

Six species of Fragaria together with their subspecific entities are described and typified, and their chromosome number is given. A total of 392 collections have been investigated cytologically. So far as it seemed necessary for interpretation, historical notes are added. The following taxa are discussed: F. vesca (four subspecies, five forms, three cultivars), F. viridis, F. moschata, F. virginiana (four subspecies), F. chiloensis (four subspecies, two forms), F. × ananassa (two nothomorphs). New status is given to numerous taxa and two new taxa are described.
THE RATE OF DRY WEIGHT ACCUMULATION IN MARQUIS WHEAT AS AFFECTED BY TEMPERATURE AND LIGHT INTENSITY
Authors: Friend D. J. C. , Helson V. A. , Fisher J. E.
Published: August 2008

Plants were grown to the stage of anthesis at constant temperatures from 10 to 30 °C and under continuous illumination at intensities ranging from 200 to 2500 ft-c. The absolute growth rate was maximal at the time of ear emergence. The relative growth rate declined continuously with time; the rate of decline was greatest at the higher temperatures and light intensities. The optimal temperature for the mean absolute growth rate over the whole growth period was 20–25 °C. The optimum for the mean relative growth rate was 15–20 °C. This difference is attributed to the faster rate of floral development at high temperatures. Both absolute and relative growth rates increased with increasing light intensity up to 2500 ft-c.
BIOASSAY OF ANTIBIOTIC P-9 BY THE DIRECT RESPONSE OF STEM RUST OF WHEAT
Authors: Hagborg W. A. F. , Chelack W. S.
Published: August 2008

A simple medium was found for the production of antibiotic P-9 used in experiments for the control of stem rust of wheat.A rust-infection bioassay method for the estimation of the potency of different production lots of filtrate was developed; potency was measured as the proportionate inhibition of stem rust (Puccinia graminis Pers. f. sp. tritici Erikss. & Henn. race 15B) infection on wheat seedlings in relation to log concentration of the material under test. The data from the bioassays took the form of a sigmoid curve when the concentrations were plotted arithmetically and of a straight line when they were plotted logarithmically. The slope of a weighted mean regression line based on 11 assays was regarded tentatively as characterizing pure antibiotic P-9.When the data of the 11 assays were adjusted for differences in potency between assays, the weighted mean regression line was statistically significant at the 1% point of probability. It is hoped that the slope of this line characterizes the pure antibiotic P-9 sufficiently well to be a useful tool in estimations of the relative purity of fractions obtained in the progressive purification of the antibiotic. Regression lines that differ from it substantially in slope may be suspected of influence from some extraneous factor.
ACTION AND INTERACTION OF MONOCHROMATIC LIGHT ON PHOSPHATE METABOLISM OF GERMINATING LETTUCE SEEDS
Authors: Surrey Kenneth
Published: August 2008

A previously described photoresponse of lettuce seed germination to red and far-red light is shown to be paralleled by a response of phosphate metabolic activity: (1) When seeds were continuously irradiated, red light accelerated and far-red suppressed their phosphate uptake and esterification. (2) The influence of monochromatic light on phosphate metabolism of seeds, determined after 36 and 64 hours of germination, respectively, indicated maximum potentiation between 550 and 650 mμ, maximum suppression beyond 700 mμ, and partial suppression at 475 mμ. Stimulation was encountered at 400 mμ, but with shorter wavelengths of the ultraviolet spectrum, suppression appeared again. (3) Photoactivation of phosphate metabolism in response to each of the three loci (550, 600, and 650 mμ, i.e., green, orange, and red light, respectively) of the potentiating spectral band was reversed by far-red (750 mμ) light. These activations and inhibitions could be reversed several times in an alternating sequence. Complete reversibility depended entirely upon the magnitudes of the radiant flux for the two counteracting wavelengths, and this was characteristic for each pair of antagonistic wavelengths. In view of the association of phytochrome with the isolated mitochondria and of the specific manner in which their phosphorylation activity is influenced by light, it is suggested that a part of the energy flow required for cellular development may be channeled through the mitochondrial–phytochrome system.
THE GENUS DASYCLONIUM J. AGARDH
Authors: Scagel Robert F.
Published: August 2008

The genus Euzonia Kylin is rejected because the species included in it form only part of an evolutionary series of closely related entities hitherto referred to the genus Euzoniella Falkenberg. Furthermore, because of the additional confusion that has resulted from referring only a part of this series to Dasyclonium J. Ag. (sensu Kylin), and because an earlier proposal to conserve Euzoniella has been rejected, it would seem best to refer all entities to the one genus Dasyclonium J. Ag. The morphological evidence resulting from a recent study of more extensive material and the types of additional species further supports this conclusion. Also supported is the opinion that D. ocellatum (Yendo) Scagel and D. flaccidum (Harvey) Kylin are probably conspecific; and, furthermore, that these questionable species might, with justification, be reduced to synonymy with D. incisum (J. Ag.) Kylin; and that D. adiantiformis (Decaisne) Scagel and D. cuneifolium (Montagne) Scagel may be merely extremes in a series of plants representative of one variable species (D. adiantiformis). These reductions to synonymy, however, should not be made until an ecological study has been undertaken to determine the limits of variability within the complex. A distinctive entity, based upon Laing's No. 40 from the Snares, New Zealand, and referred by him to Euzoniella flabellifera (J. Agardh) Laing, is described as Dasyclonium bifurcatum sp. nov.
CAMBIAL BEHAVIOR WITH REFERENCE TO CELL LENGTH AND RING WIDTH IN PINUS STROBUS L.
Authors: Bannan M. W.
Published: August 2008

The relationships between width of annual rings, length of wood cells, and frequency of anticlinal (multiplicative) divisions in fusiform cambial cells were studied by reference to trees of various growth patterns. The trees selected ranged from 8 to 20 in. diameter and included both open-grown specimens with branches close to the ground and forest types with tall, slender shafts. Much fluctuation was noted among individual trees, but in general there was, in the peripheral growth, an inverse relationship between length of wood cells and width of annual rings. The frequency of anticlinal divisions in the cambium remained at a more or less uniform rate in trees with rings from 1.5 to 5 mm wide, but rose sharply when ring width fell below 1.3 mm. This was in contrast to the situation observed earlier in Thuja occidentalis where the rise in frequency of anticlinal divisions was slight and occurred only in trees with rings less than 0.3 mm wide.
PHYSIOLOGICAL STUDIES ON THE PYCNOPORUS SPECIES
Authors: Madhosingh Clarence
Published: August 2008

The physiology of three groups of morphologically similar wood-rotting polypores, which produce extracellular oxidases as indicated by positive reactions with guaiacol, was studied comparatively.The inability to oxidize tyrosine and phenols, including guaiacol, in 'spot tests' distinguished P. cinnabarinus (Jacq. ex Fr.) Karst. from P. sanguineus (L. ex Fr.) Murr. and P. coccineus (Fr.) Bond. and Sing. growing on a tyrosine medium.The possible application of these methods for obtaining more specific distinctions within the two larger groups, the 'guaiacum-positive', lignin-decomposing and the 'guaiacum-negative' organisms, is indicated.The three groups separated on the basis of differential growth on malt extract agar at 35.2 °C.P. cinnabarinus grew slower generally than P. sanguineus and P. coccineus on malt extract agar between 20 °C and 40 °C and on various nitrogenous and phenolic substrates.There were indications that differences in the history of the isolates might have been a factor contributing to the intraspecific variations observed in growth and pigmentation.The pigments obtained from malt extract cultures of the three groups were the same.Eighteen, out of a total of 41 different ninhydrin-reacting compounds, were common to all isolates of the three groups grown in asparagine medium. Three compounds were specific to certain groups and 20 were distributed randomly between the isolates.
TRANSLOCATION OF THE PRODUCTS OF PHOTOSYNTHESIS TO ROOTS OF PINE SEEDLINGS
Authors: Shiroya T. , Lister G. R. , Krotkov G. , Nelson C. D. , Slankis V.
Published: August 2008

Pinus strobus or P. resinosa seedlings, 2 or 3 years old, were illuminated in a closed chamber for 1 hour in the presence of C14O2. This was followed by various periods up to 24 hours under different conditions of light and darkness. Then each seedling was divided into its shoot, stem, and roots, and these were extracted separately with 80% ethanol. The extracts were resolved first on resins into sugar, amino acid, and organic acid fractions and then resolved further by paper chromatography. The C14 content of various fractions and of the eluted compounds was determined by plating and counting their aliquots. Ethanol-insoluble residue was oxidized and counted as BaC14O3.Eight hours after administration of the C14O2, 91 to 94% of the total C14 was found in the ethanol-soluble fractions of shoot, stem, or root. In shoots sugars were found to represent more than 95% of the ethanol-soluble photosynthate, with sucrose forming three-quarters of it. In stem and roots sucrose represented from 75 to 94% of the translocated photosynthate. Raffinose, glucose, and fructose were present in both stem and root.Seedlings with poorly developed root systems translocated less photosynthate to roots than those with good roots. Seedlings, which prior to the experiments were grown in full sunlight or 2500 ft-c artificial illumination translocated more photosynthate to roots than those grown in 6% of full sunlight or 250 ft-c artificial light. Stronger light during translocation itself also had a slight stimulatory effect.Seedlings, which were illuminated in the presence of C14O2 for 1 hour and then retained in a closed chamber for a further period of 7 hours, translocated a larger fraction of absorbed C14 to their roots than comparable seedlings transferred to air after feeding C14O2.
CHRYSOSPORIUM AND SOME OTHER ALEURIOSPORIC HYPHOMYCETES
Authors: Carmichael J. W.
Published: August 2008

A revised classification and nomenclature is proposed for some molds which produce hyaline, single-celled aleuriospores. Chrysosporium Corda is revived as a suitable genus for fungi which have been referred to Aleurisma Auct. non Link. Blastomyces, Emmonsia, Geomyces, Gilchristia, Glenosporella, Myceliophthora, and Zymonema are placed in synonymy under Chrysosporium. The typification and status of the following genera is discussed: Acladium, Aleurisma, Allescheriella, Bactridiopsis, Balanium, Blastomycoides, Botryotrichum, Chlamydomyces, Coccospora, Glenospora, Glenosporopsis, Histoplasma, Humicola, Mammaria, Monosporium, Monotospora, Myceliophthora, Mycogone, Oidium, Paracoccidioides, Rhinocladium, Scedosporium, Sepedonium, Sporothrix, Sporotrichum, Stephanoma, and Trichophyton.Chrysosporium asperatum and C. tropicum are proposed as new species. Six new combinations and one new name are proposed in Chrysosporium. One new combination is proposed in Paecilomyces. A key to the species of Chrysosporium is included as well as descriptions and illustrations of the species.
PHOSPHATE-DISSOLVING MICROORGANISMS ON SEED AND IN THE ROOT ZONE OF PLANTS
Authors: Katznelson H. , Peterson E. A. , Rouatt J. W.
Published: August 2008

A high proportion (40–70%) of the bacteria on most of the seed tested solubilized phosphate precipitated in agar; flax and red clover were two striking exceptions with 11% and 24% respectively. The percentage incidence of these bacteria was considerably lower on the roots and in the rhizosphere of four out of the five crop plants studied than on their seed, being in the order of 10%. There was no strong evidence of a selective effect of plant roots on these organisms although barley appeared to favor them and oats to repress them somewhat.Phosphate-dissolving fungi were readily isolated from seed and plant roots. Cereal seed carried surprisingly few such fungi whereas grasses and clover had greater numbers. The phosphate-dissolving fungi isolated most frequently were species of Penicillium, Aspergillus, and Rhizopus; in addition, Candida, Oidiodendron, and Pseudogymnoascus species were isolated from roots and root-free soil.
STREPTOTINIA CAULOPHYLLI SP. NOV. PRODUCED IN CULTURE
Authors: Elliott Mary E.
Published: August 2008

Streptotinia caulophylli sp. nov. is described as a new species. Apothecia were produced in culture from conidia borne on streptoform conidiophores isolated from an overwintered petiole of Caulophyllum thalictroides. The connection between the perfect state and the imperfect state has been established. Microconidia were produced on the tips of spermatiophores and also on the tips of conidial germ tubes.
QUANTITATIVE CHANGES OF SOLUBLE CARBOHYDRATES IN STEMS OF SOLID- AND HOLLOW-STEMMED WHEATS DURING GROWTH
Authors: Lopatecki L. E. , Longair E. L. , Kasting R.
Published: August 2008

Soluble carbohydrate of stems of wheat grown in the Lethbridge area followed a similar trend in solid- and hollow-stemmed varieties. At the time of heading, most soluble carbohydrate was present as fructose, glucose, and sucrose. After heading, the quantities of reducing sugars declined, while oligosaccharide and fructosan built up. Oligosaccharide formed the dominant carbohydrate stored in stems prior to ripening of the grain. In general, the contents of soluble carbohydrate in stems of Golden Ball were at a higher level than those of Rescue or Thatcher. Rescue and Golden Ball, two solid-stemmed varieties resistant to the wheat stem sawfly, showed no consistent deficiency of soluble carbohydrate in stems at any growth period.
A LEAF-SPOTTING DISEASE OF HYBRID AND NATIVE ASPEN
Authors: Boyer M. G.
Published: August 2008

During 1958, a conspicuous foliage disease was observed on the hybrid aspen Populus tremuloides Michx. × P. tremula L. The symptomology, importance, and probable cause of this disease are discussed. The disease on hybrid aspen was found to be essentially identical with a relatively innocuous leaf spot disease of native aspen.
RESPIRATION AND PHOSPHORUS-CONTAINING COMPOUNDS IN NORMAL AND TUMOR TISSUES OF RED BEET ROOTS
Authors: Scott K. J. , Smillie R. M. , Krotkov G.
Published: August 2008

A comparative analytical study has been made of normal and tumor tissues of red beet roots. Per μg DNA, the two tissues had similar cell numbers, protein contents, and respiratory rates. On the other hand, the fresh and dry weights, acid-soluble phosphorus including nucleotides, acid-labile phosphorus, and inorganic phosphate were higher in the normal tissues. Tumor tissues contained more RNA. These results are discussed in relation to the cellular metabolism of the normal and tumor tissues and it is suggested that the main metabolic differences between these tissues lie in the utilization of respiratory energy, rather than in its production.
TAXONOMY OF THE GENUS CARDARIA WITH PARTICULAR REFERENCE TO THE SPECIES INTRODUCED INTO NORTH AMERICA
Authors: Mulligan Gerald A. , Frankton Clarence
Published: August 2008

In the opinion of the authors, the genus Cardaria contains five species. They are described and a key is given. Two taxa are transferred from Lepidium to Cardaria, as C. PROPINQUUM and its variety AURICULATUM. Chromosome numbers reported for C. chalepensis, 2n = 80 and C. pubescens, 2n = 16, are new, as are those of naturally occurring and previously unrecognized hybrids between C. chalepensis and C. draba, 2n = 64. Three species, C. draba, C. chalepensis, and C. pubescens, are introductions to North America, where they have become prominent agricultural weeds. The morphological and specific limits of these three species are discussed in detail.
THE BRYOLOGICAL FLORA OF MOUNT YAMASKA, ROUVILLE COUNTY, QUEBEC
Authors: LeBlanc s. c. Fabius
Published: August 2008

In the industrialized Saint Lawrence Valley, Quebec, the climax vegetation is rather well preserved on the Monteregian Hills, a series of eight small mountains east of Montreal. The bryological flora of one of these monadnocks, Mount Yamaska, has been intensively studied. Typical bryophytes from several habitats were investigated. Growth forms and their biological spectrum on two substrata were analyzed. Finally the author has catalogued over 220 bryophyte taxa for this small ([Formula: see text] sq. miles) area.
SELECTIVE ACTION OF FUNGUS-INHIBITORY PROPERTIES OF BALSAM FIR HEARTWOOD
Authors: Etheridge D. E.
Published: August 2008

Heartwood of balsam fir (Abies balsamea (L.) Mill.) has been found highly selective for Stereum sanguinolentum Alb. & Schw. ex Fr. and other primary invaders of this host. In tests with a number of species of fungi, including several important tree pathogens, this substrate exhibited fungus-inhibitory properties hitherto unsuspected on the basis of tests with heat-sterilized material. Tests have shown that the inhibitory property is more active in heart-wood than in sapwood, is substantially reduced by wet heat ([Formula: see text] hour at 100 °C), and is relatively unaffected by dry storage (3 years at room temperature). The selective action did not depend upon the microbiological condition of the wood.
MORPHOLOGICAL CHARACTERISTICS OF CERATOCYSTIS ULMI (BUISM.) C. MOREAU IN AMERICAN ELM TREES
Authors: Ouellette G. B.
Published: August 2008

Observations on the development of Ceratocystis ulmi (Buism.) C. Moreau show that the fungus produces large numbers of spores (microspores) as small as 0.5 μ in diameter in the xylem of American elms (Ulmus americana L.). The development of microspores has been followed from their germination into fine, short hyphae to their formation endogenously and exogenously in association with mature hyphae and spores.
STUDIES ON FUSARIUM WILT OF BANANAS: IX. COMPETITIVE SAPROPHYTIC ABILITY OF F. OXYSPORUM f. CUBENSE
Authors: Stover R. H.
Published: August 2008

Pieces of propylene oxide fumigated banana leaves, and detached roots of Musa balbisiana, were used as substrates to study the colonizing ability of F. oxysporum f. cubense clone C in competition with the natural flora of different soils. Populations of clone C ranging from about 5000 to 100,000 spores per gram of soil colonized in 3 days a variable but low percentage of baits, usually being recovered from less than 20% of the leaf and root fragments sampled. Colonization of leaf baits also occurred in submerged soils containing 60,000 or more spores per gram of clone C, but was reduced one-half or more in comparison with non-submerged soil. In Honduras banana soil, F. solani, Rhizoctonia spp., and sometimes Rhizopus spp. were dominant colonizers. Saprophytic F. oxysporum was also recovered from some of the baits along with clone C. Clone C was recovered from a small percentage of grass roots colonized in situ. In diseased banana plants, clone C was a predominant colonizer of portions of about 20% of the decaying main roots. Colonization presumably occurred outward into the decaying cortex from a parasitically established base in the infected stele.In banana soils F. oxysporum f. cubense, even at populations of 100,000 per gram of soil, was a weak competitor in comparison with F. solani and Rhizoctonia spp. at natural populations of less than 2000 per gram of soil. Natural populations of F. solani and F. roseum dominated F. oxysporum in general in saprophytic competition for various substrates. Nevertheless, the results showed that F. oxysporum f. cubense must at times take advantage of favorable micro-environments to successfully invade a small percentage of colonizable sites on roots and other substrates. In these instances, the banana wilt pathogen has probably escaped competition with more vigorous Fusarium and other saprophytes because of random spore distribution in soil.
THE INFLUENCE OF TEMPERATURE ON THE LOCATION AND DEVELOPMENT OF DECAY FUNGI IN LODGEPOLE PINE LOGGING SLASH
Authors: Loman A. A.
Published: August 2008

In an investigation to determine the fungal flora of lodgepole pine logging slash and the growth rates and decaying abilities of the principal fungi in vitro as contrasted with conditions in nature, four hymenomycetes were isolated consistently and proved to cause most of the decay; Lenzites saepiaria Wulf. ex Fr., Peniophora phlebioides Jacks. and Dearden, Stereum sanguinolentum Alb. and Schw. ex Fr., and Coniophora puteana (Schum. ex Fr.) Karst. These four fungi comprised 80% of the basidiomycetes isolated from slash. Peniophora phlebioides predominated in the upper portions of individual pieces of slash, Lenzites saepiaria in the center, and Coniophora puteana and Stereum sanguinolentum in the lower portions. Relatively broad temperature ranges and high temperature optima were demonstrated for P. phlebioides and L. saepiaria to grow and cause decay, in contrast with the narrower temperature ranges and lower optimal temperatures demonstrated for C. puteana and S. sanguinolentum. The internal temperatures of slash were proved to fluctuate between wider extremes in the upper portions of slash than in the lower portions. This is believed to be a partial explanation of the characteristic distributions of individual fungi within slash. The relative decaying abilities of the four main fungi as indicated by wood block tests, in decreasing order of importance were: L. saepiaria, C. puteana, P. phlebioides, S. sanguinolentum. Because of its greater frequency, however, P. phlebioides probably ranks higher in the scale of slash decayers than C. puteana.
DORMANCY STUDIES IN SEED OF AVENA FATUA: 3. A RELATIONSHIP BETWEEN MALTASE, AMYLASES, AND GIBBERELLIN
Authors: Simpson G. M. , Naylor J. M.
Published: August 2008

Initiation of germination in excised embryos requires an exogenous energy source. Normally this is obtained from the endosperm. In dormant seeds the hydrolysis of starch is blocked despite the fact that dormant and non-dormant seeds contain similar amounts of α- and β-amylases. Alone or in combination the amylases are unable to break down raw endosperm starch granules to simple sugars in vitro. Exogenous maltase in combination with α-amylase hydrolyzes raw starch to glucose. Exogenous maltase eliminates the requirement for exogenous sugar. Examination of the maltase content of imbibed dormant and non-dormant seeds showed a marked increase in non-dormant seeds during the first 40 hours. This does not occur in dormant seeds unless they are treated with gibberellic acid. The results lead to the conclusion that an important effect of gibberellic acid is to induce the synthesis of maltase or in some way activate the preformed enzyme.
CYTOTAXONOMY OF THE NATIVE AND ADVENTIVE SPECIES OF HORDEUM, EREMOPYRUM, SECALE, SITANION, AND TRITICUM IN CANADA
Authors: Bowden Wray M.
Published: August 2008

Cytotaxonomic data are reported for the genera Hordeum, Eremopyrum, Secale, Sitanion, and Tritícum. New nomenclature is: Hordeum geniculatum All. f. hirtellum (Degen ex Nevski) Bowden; Hordeum jubatum L. emend, subsp. × intermedium Bowden (subsp. breviaristatum Bowden × subsp. jubatum); Hordeum jubatum L. emend, subsp. breviaristatum Bowden; Hordeum leporinum Link var. simulans Bowden; and Eremopyrum bonaepartis (Spreng.) Nevski f. hirsutum (Bertol.) Bowden.Voucher specimens are cited for the following chromosome number determinations:(1) diploid, 2n = 14: Hordeum californicum, H. geniculatum, H. glaucum, H. marinum, H. pusillum, and Eremopyrum bonaepartis f. bonaepartis.(2) tetraploid, 2n = 28: Hordeum depressum, H. geniculatum, H. jubatum subsp. jubatum, H. jubatum subsp. × intermedium, H. jubatum subsp. breviaristatum, H. leporinum var. leporinum, H. murinum, Eremopyrum bonaepartis f. bonaepartis, E. bonaepartis f. hirsutum, and E. distans.(3) hexaploid, 2n = 42: Hordeum arizonicum and H. leporinum var. simulans.
The White River Ash: largest Holocene Plinian tephra
Authors: Lerbekmo J. F.
Published: August 2008

The White River Ash is a bi-lobate tephra in eastern Alaska, Yukon Territory, and western Northwest Territories. Plinian-type eruptions produced the north lobe ∼1900 years BP and the larger east lobe ∼1250 years BP (14C years). Present evidence favors the vent for the east lobe to be beneath the Klutlan Glacier. East lobe pumice is not present atop Mt. Churchill, so the pumice there must belong to the north lobe and is also likely to have come from a vent beneath the Klutlan Glacier. Isopachs of the east lobe, now known to stretch as far east as Great Bear Lake, indicate an east lobe volume of ∼47 km3. Thickness and grain size of the east lobe decay in exponential fashion, producing straight line plots when the thickness half-distance and clast half-distance are plotted against the square root of the isopach area, the proximal slope being steeper than the distal. The east lobe eruption is indicated to have been into a wind of about 10 m/s and to have produced an eruptive cloud height of ∼45 km. The eruption rate was at least 2.8 × 108 kg/s.
Comparison of Sm II transition probabilities
Authors: Lawler J E , Hartog E A , Sneden C , Cowan J J
Published: August 2008

This Research Note provides a comparison of experimental atomic transition probabilities in Sm~II from two recent publications. Basic data of this type for rare-earth spectra, including Sm~II, are very difficult to determine using ab-initio theoretical methods. Experimental programs are underway in several laboratories to determine these data for ongoing astrophysical studies of the origins of the chemical elements. The two recent and nearly simultaneous publications, which were based on very different experimental methods, provide transition probabilities in good, but not perfect, agreement.PACS Nos.: 32.70.Cs, 32.70.Fw, 32.30.Jc
Large-amplitude dust-acoustic solitary waves in an electron-depleted hot dusty plasma with trapped ions
Authors: Tribeche M , Younsi S , Zerguini T H
Published: August 2008

A theoretical model is presented to show the existence, formation, and possible realization of large-amplitude dust-acoustic solitary potentials in electron-depleted hot dusty plasma with trapped ions. These nonlinear localized structures are self-consistent solutions of the Vlasov equation in which the ion response is non-Maxwellian due to the ion trapping in the large-amplitude plasma potentials. Emphasis is given to the role of the grain temperature. Interestingly, one finds that the effect of increasing the dust temperature is to restrict the domain of allowable Mach numbers. The latter enlarges when the relative amount of trapped ions is increased. Furthermore, the nonlinear potential shrinks and exhibits smaller depth and smaller width than the one involving cold dust grains. The strong localization of the dust particles becomes less pronounced when the dust temperature is increased. The results complement and provide new insights into previously published results on this problem and their relevance to space dusty plasmas is pointed out.PACS Nos.: 52.27.Lw; 52.35.Fp; 52.35.Sb; 52.35.Tc; 52.35.Mw
Flow and heat transfer of a micropolar fluid sandwiched between viscous fluid layers
Authors: Umavathi J C , Kumar J Prathap , Chamkha A J
Published: August 2008

In the present analysis, a two-fluid model for blood flow through a horizontal channel is studied. The model essentially consists of a core region assumed to be a micropolar fluid and two viscous (Newtonian) fluid regions. Using the boundary and interface conditions proposed by Ariman et al. (J. Appl. Mech. ASME, 41, 1 (1974)), analytical expressions for velocity, microrotation velocity, and temperature are obtained. The solutions are also evaluated numerically and shown graphically for various governing parameters such as the material parameter, viscosity ratio, conductivity ratio, Eckert and Prandtl numbers on velocity, microrotation velocity, and temperature profiles. In addition, results for the rate of heat transfer, mass flow rate, and skin friction for different values of the physical parameters are presented in tabular form. It is found that effect of the material parameter is to suppress the flow and the viscosity ratio promotes the flow. It is also interesting to note that the material parameter and viscosity ratio affect the position of the point of flow separation for which the flow nature is reversed. Also, considering the solvent viscosity for air, water, and glycerin, the cell rotation on the flow has been tabulated for 0%, 20%, and 40% concentration. PACS Nos.: 44.15+a, 44.35.+c
Microscopic, quantum derivation of cranking model for nuclear collective rotation: harmonic oscillator case
Authors: Gulshani P
Published: August 2008

In this article, the conventional semiclassical one-dimensional cranking model (CR), which is commonly used to investigate rotational structures of deformed nuclei, is derived from microscopic, quantum first principles for the harmonic oscillator case. The space-fixed particle coordinates are canonically transformed to an Euler angle and a set of 3N – 1 intrinsic coordinates to decompose the nuclear Hamiltonian into intrinsic and collective rotational components plus a Coriolis-centrifugal term that couples the intrinsic and rotational motions. To overcome the difficulties associated with finding an appropriate set of intrinsic coordinates, the rotational component in the transformed Hamiltonian is expressed in terms of the space-fixed coordinates and momenta by taking the commutator of the original Hamiltonian with the Euler angle, and by choosing an explicit expression for the Euler angle in terms of space-fixed particle coordinates. The intrinsic component in the transformed Hamiltonian is then the difference between the original Hamiltonian and the rotational component. The nuclear wave function is chosen as the product of an intrinsic function and an eigenfunction of the angular momentum operator (as in the unified rotational model). The Hamiltonian and Schrodinger equation for the intrinsic system become functions of the angular-momentum quantum number and intrinsic operators that are expressed in terms of space-fixed particles coordinates and momenta. The intrinsic Schrodinger equation is then reduced to that of a one-body operator using Hartree–Fock mean-field approximation. The intrinsic mean-field Hamiltonian is chosen to be an anisotropic harmonic oscillator Hamiltonian, and the Hartree–Fock mean-field equation is unitarily transformed to an equation resembling that of the CR but with oscillator frequencies and angular velocity that are microscopically and quantum mechanically determined. The unitary transformation is selected such that the model predicts the kinematic rigid-body moment of inertia, as does the CR when self-consistency condition is used.PACS Nos.: 21.60.Ev, 21.60.Fw, 21.60.Jz
Colour change and substrate selection in larval Ischnura verticalis (Coenagrionidae: Odonata)
Authors: Moum Susan E. , Baker Robert L.
Published: August 2008

Larvae of Ischnura verticalis reared on either green or brown substrates showed significant differences in colour; larval colour tended to match that of the substrate. When presented with different-coloured substrates, both green and brown animals chose brown in preference to green. Preference for brown was not significantly altered by the presence of fish. Green larvae on green substrates were at significantly greater risk to predation by fish than they were on brown substrates. In addition, green larvae on brown substrates captured significantly more larval mayflies (Callibaetis sp.) than did green larvae on green substrates. Results suggest that the adaptive significance of colour change and choice of substrates is related to both avoidance of predators and concealment from potential prey.
A genetic analysis of meristic and morphometric variation in chum salmon (Oncorhynchus keta) at three different temperatures
Authors: Beacham Terry D.
Published: August 2008

A nested mating design was used in which 10 males were mated with 20 female chum salmon (Oncorhynchus keta), and individuals from each of the 20 families were maintained at 6, 10, and 14 °C from egg fertilization until juveniles reached a fork length of about 61 mm. Variation in 11 morphometric and 3 meristic characters was evaluated. Rearing temperature had a marked effect on juvenile morphometric variation, enough to assign correctly 91% of the juveniles reared at 14 °C, 90% of the juveniles reared at 10 °C, and 95% of the juveniles reared at 6 °C. The addition of meristic character variation increased the classification accuracy to 97, 92, and 96%, respectively. As rearing temperatures increased, the observed levels of fluctuating asymmetry for the three meristic characters increased. Morphometric characters tended to have lower heritabilities than did meristic characters. Genotype–temperature interactions generally accounted for between 10 and 30% of observed phenotypic variation for most characters.
Variation in egg weight in the Bengalese finch (Lonchura striata var. domestica)
Authors: Coleman Ronald M. , Whittall Robin D.
Published: August 2008

Variation in egg weight was examined in 29 clutches (155 eggs) from 14 pairs of captive Bengalese finches. For clutches of four and seven eggs, egg weight varied more within than among clutches. The opposite was true for clutches of five, six, and eight eggs and when all clutches of four to eight eggs were pooled. Egg weight increased linearly with laying sequence for clutches of four, five, and eight eggs, and for clutches of four to eight eggs combined. Egg weight also varied with clutch size: large clutches contained heavier eggs throughout the clutch than did small clutches. Egg weight was not correlated significantly with the amount of food eaten around the time of egg laying. Furthermore, food consumption did not increase linearly through the laying sequence as did egg weight. These patterns suggest that complex investment allocation decisions underlie egg weight variation in the Bengalese finch.
Survival of radio-collared caribou (Rangifer tarandus caribou) from the George River herd, Nouveau-Québec – Labrador
Authors: Hearn Brian J. , Luttich Stuart N. , Crête Michel , Berger Maria B.
Published: August 2008

Between September 1983 and June 1987, 175 caribou (Rangifer tarandus caribou) from the George River caribou herd were captured and radio-collared. By October 1987, 42 of those had died: 15 were apparently killed by predators, 8 were legally shot, 4 appeared to have died proximally from malnutrition, 1 died from an accident, and cause of death could not be determined for 14 others. Seasonal and annual survival rates were estimated most precisely for adult (≥ 24 months) females, but a consistent trend towards lower survival at the end of the study period was evident in all age and sex groups. Decreasing summer survival was responsible for the lowering of annual survival rates, as winter survival was relatively constant over the study period. Using our calculated age-specific survival rates, and estimates of age-specific fecundity, the survival–fecundity rate of increase (rs) for the female segment of the herd was 0.12 for 1983–1984 and −0.01 for 1986–1987. Decreasing summer survival thus appears to have been of greatest importance in reducing rs to zero and halting the growth of the herd. Density-dependent mechanisms acting on the George River caribou herd appear different from those described for caribou herds regulated by winter forage.
Reproductive seasonality in harbour porpoises, Phocoena phocoena, from the Bay of Fundy
Authors: Read Andrew J.
Published: August 2008

I examined the reproductive tracts from 244 harbour porpoises, Phocoena phocoena, captured incidentally in commercial fishing operations in the Bay of Fundy during June to September, 1985–1988. Evidence from follicular growth and the development of corpora lutea suggests that ovulation and conception occur in late June. This interpretation is supported by subtracting the duration of gestation from estimated mean birth date, and also by seasonal changes in testicular mass. Six or 7 weeks of preimplantation pregnancy follows conception and foetuses are first detectable in early August. Gestation lasts for approximately 10.6 months and parturition occurs during mid-May. Females that fail to conceive during the breeding season must wait 12 months for another opportunity to mate. Estimates of pregnancy rate must account for the seasonal nature of reproduction. The observed pattern of reproductive seasonality may reflect seasonal variation in prey quality, and perhaps availability.
Étude ultrastructurale des bourgeons de régénération mis en place après amputation de la ventouse postérieure chez l'hirudinée rhynchobdelle adulte Helobdella stagnalis
Authors: Cornec Jean-Pierre
Published: August 2008

Tissue behaviour in the rhynchobdellid hirudinean, Helobdella stagnalis, was studied at the ultrastructural level between 8 and 18 days after amputation of the posterior sucker. Ultrastructural transformations of the regenerative buds progress in a sequential mode. They are successively characterized by nerve fiber regeneration, differentiation of the adhesive sole, and muscular and conjonctive tissues reconstitution with cells provided by the stump. Adhesive sole differentiation involves, first, the basal cells, which occurs without previous dedifferentiation, then the sensory receptors and, lastly, the glandular cells. Some basal epidermal cells are at the origin of the mucus glandular cells. The piriform and tubular phenotypes must be considered as successive maturation stages of the same clone. The conjunctive extracellular matrix probably plays a primordial role in the differentiation of the specific tubular glands of the adhesive sole.
Forces of biting, body size, and masticatory muscle tension in the opossum Didelphis virginiana
Authors: Thomason J. J. , Russell A. P. , Morgeli M.
Published: August 2008

Analyses of masticatory mechanics in the opossum have been used to infer how the ancestors of mammals acquired the ability to masticate food. The forces of biting are important characteristics of the masticatory apparatus, but few such data are available for the opossum. We maximally stimulated the jaw adducting muscles of ten opossums under anaesthesia and recorded the force output between the first molars. The data show some scatter, but significant regressions were obtained of peak force of biting on both body weight and skull length. These regressions give a means of predicting a range of maximal forces of biting for animals of known weight or, with less confidence, known skull length. For three individuals, body weight, stimulated forces, and peak forces of voluntary biting were recorded at intervals over a 6-month period. Regressions of force on weight for each of the three animals are not significantly different from the slope for all ten. Thus any ontogenetic component of variation in the data for all ten animals cannot be factored out. Maximum muscle stresses (tension per unit area) in the jaw adducting muscles were estimated from peak forces and the cross-sectional areas and moment arms of each muscle, measured after dissection. The average muscle stress of 317 kPa is well within the range of 147–392 kPa reported for other vertebrates. The dissection procedure is therefore validated as a means of estimating peak forces that may have acted in the masticatory system of museum specimens.
Comparative electron microscopic investigation of the nuchal organs in Protodriloides, Protodrilus, and Saccocirrus (Annelida, Polychaeta)
Authors: Purschke Günter
Published: August 2008

The nuchal organs of the interstitial polychaetes Protodriloides chaetifer, Protodriloides symbioticus, Protodrilus ciliatus, Protodrilus adhaerens, Saccocirrus krusadensis, and Saccocirrus papillocercus were investigated by scanning and transmission electron microscopy. These organs vary from spherical to elongated ciliary brushes and usually lie in shallow pits. In P. symbioticus only a reduced nuchal organ exists, whereas the other species all have well-developed nuchal organs of similar structure consisting of ciliated supportive cells and bipolar primary sensory cells. The perikarya of the sensory cells form the nuchal ganglia, which lie behind the brain. Different retractor muscle cells are attached to the ciliated cells. The number of sensory cells varies from 4 to about 90 according to the size of the nuchal organs. Each sensory cell gives rise to a distal process (dendrite), and 4–25 processes at a time unite to form bundles that penetrate between the ciliated cells. Apically the dendrites terminate in small sensory bulbs, each bearing several microvilli and a modified cilium. The sensory cilia usually branch, lose their axonemes, and extend as microvillus-like structures into the olfactory chamber representing an extracellular space below the reduced cuticle. Specific microvillar processes of the ciliated cells form a dense cover above the cuticle which is only penetrated by the motile cilia of these cells. The ciliated cells are highly pinocytic. The nuchal organs of the species investigated show striking similarities to those of spionids.
Behavioural and physical adaptations of three insects that feed on the phototoxic plant Hypericum perforatum
Authors: Fields Paul G. , Arnason John T. , Philogène Bernard J. R.
Published: August 2008

Chrysolina hyperici, C. quadrigemina (Coleoptera: Chrysomelidae), and Anaitis plagiata (Lepidoptera: Geometridae) all feed on St. John's-wort (Hypericum perforatum), in spite of the presence of the phototoxin hypericin, which has been shown to be toxic to other insects. Fourth instar Chrysolina spp. larvae fed at dawn, then hid in the soil for the remainder of the day. When larvae were forced to remain in the light, mortality was positively correlated with light intensity. This susceptibility to light may be related to the highly transparent larval cuticle which transmitted over 60% of the photosensitizing wavelengths (540–610 nm). Chrysolina adults differed from the larvae in that they were sun loving, fed on St. John's-wort during the day, and basked at the tips of the branches. Adult cuticles only transmitted 0.1–0.2% of the photosensitizing wavelengths. Third instar A. plagiata larvae remained on the plant at all times, feeding both during the day and night. In the 5th instar, larvae burrowed into the soil during the day and fed mostly at night, much like late instar Chrysolina larvae. However, A. plagiata larvae suffered no ill effects if forced to remain in the light. Part of their resistance to photosensitization may be explained by the low transmittance of their cuticle (20%).
Seasonal epidermal molt in beluga whales, Delphinapterus leucas
Authors: Aubin D. J. St. , Smith T. G. , Geraci J. R.
Published: August 2008

Epidermal morphology and proliferation were examined in beluga whales during three phases of their annual cycle: spring migration from oceanic wintering grounds, summer occupation of estuaries in Hudson Bay, and return migration in fall. Incursion into relatively warm brackish water was associated with decreased thickness of the stratum externum and sloughing of a superficial layer of degenerative epidermal cells, changes that resulted in the loss of a distinctive yellow hue apparent over the dorsal body surface of whales examined during spring migration. Proliferation rate, determined by incorporation of tritiated thymidine in germinal cells, averaged 13.8–16.6% in all three seasons, but exceeded 20% in 7 of 16 whales examined in the estuaries; similarly high values were not observed during spring migration, and in only one of nine animals sampled in the fall. Average proliferation rate in 13 captive belugas was 14.2–16.6%, two to three times higher than any reported value for other cetaceans or terrestrial mammals. Epidermal turnover time in a single whale studied over a 6-week period was estimated to be 70–75 days, comparable to that in bottlenose dolphins, but indicating a much higher rate of cell migration. In estuaries, elevated temperature and low salinity are presumably responsible for accelerating turnover of superficial cells, and may contribute to elevated proliferation rates by stimulating blood flow to the germinal layer.