bluuebunny/crossref_metadata_2025 huggingface dataset:
Growth forms in the Alismatales. I. Alisma triviale and species of Sagittaria with upright vegetative axes
Authors: Lieu S. M.
Published: November 2007

Various aspects of the growth form of seven species of Alisma and Sagittaria were investigated. Of the four studied in detail, all have a short, upright stem which undergoes apical bifurcation to form the inflorescence and a continuation vegetative axis. Each season, three inflorescences are initiated in a distinct developmental sequence while phyllotaxy of the successive vegetative phases continues uninterrupted. The symmetry and development of both inflorescence and continuation growth are precise and similar in the species studied. There is greater variation in the pattern of development of axillary buds. This includes second-order axes attached directly to the parent plant (Alisma triviale), a new plant formed by each axillary stolon some distance away (Sagittaria latifolia and S. cuneata), or a whole sympodial system of stolon segments from each axillary bud as in Sagittaria subulata. Seed germination and seedling stages are very similar, and all show spiral phyllotaxy from the outset. The pattern of organization of each species remains relatively constant within and between different populations.
Growth forms in the Alismatales. II. Two rhizomatous species: Sagittaria lancifolia and Butomus umbellatus
Authors: Lieu S. M.
Published: November 2007

A comparative morphological study of Sagittaria lancifolia and Butomus umbellatus over their life cycles was undertaken. The two are very similar in adult form, characterized by apical bifurcation to form inflorescence and continuation growth as in other members of the Alismatidae.and also by rhizomatous growth with a subterminal apex. Embryo and seedling stages in S. lancifolia are comparable to other members of the Alismataceae previously studied. Rhizomatous form and bilateral symmetry are secondarily acquired during ontogeny. The inflorescence is leaf opposed and S. lancifolia is organizationally similar to other species of Alismataceae with upright vegetative axes. From this, a sympodial interpretation of the rhizome may be made. In contrast, the bilaterally symmetric growth form in Butomus is manifested from the start. The leaf-subtended inflorescence and other features of organization suggest that it cannot easily be compared with S. lancifolia or other members of Alismataceae. Here, a stronger case may be made for a monopodial construction. Axillary bud distributions support these conclusions. In addition, both species branch by a relatively precocious lateral bud associated topographically with the inflorescence.
A study of the flavonoids of the Minuartia rossii complex
Authors: Wolf S. J. , Denford K. E. , Packer J. G.
Published: November 2007

The major flavonoid complement of the Minuartia rossii complex has been determined. Nine flavonoid glycosides have been identified based on the common aglycones quercetin and kaempferol and the rarer C-glycoflavone isovitexin. One compound (apigenin-6-C-arabi-nosylglucosyl 7-O-glucoside) was found to be of limited distribution, being present in M. rossii and M. elegans and absent in M. austromontana. The flavonoid kaempferol 3-p-coumaroylglucoside found in the complex is relatively uncommon and therefore of chemosystematic interest. With respect to their flavonoid profiles, no differences were noted between the two chromosome races of M. elegans and no geographical variation was observed in the three taxa of the complex. The genetics of isovitexin glycosylation are discussed and evidence for the probable existence of two additional glycosylation genes is presented.
Gravity-regulated growth of collenchymatous bundle cap cells in the leaf sheath base of the grass Echinochloa colonum
Authors: Parker M. L.
Published: November 2007

Horizontally held flowering stalks of Echinochloa colonum L. bend upwards as a result of cell elongation in the lower side of the leaf sheath base. Changes in the gravity vector are perceived by statocytes. All cells of the leaf sheath base, including the collenchymatous bundle cap fibres can elongate up to threefold in response to geostimulation. Very little growth takes place in upright nodes and in the upper halves of nodes during bending. The thick walls of the collenchymatous cells are uniformly rich in pectin and remain unlignified. Nonelongating collenchymatous cells accumulate electron-dense wall material in infoldings of the plasmalemma. Elongating cells become thin walled, unincorporated wall material disappears, and a narrow, electron-dense layer of wall forms. The walls thin evenly, although under polarized light the structure of the pits may give an appearance of uneven stretching. When the gravitational stimulus is removed, growth ceases, the walls rethicken, and the electron-dense layer disappears.
Populations of fungi in a high arctic ecosystem
Authors: Widden P. , Parkinson D.
Published: November 2007

A study of the fungal flora of soils, plant leaves, and litter was undertaken on the Truelove Lowland, on the north coast of Devon Island, N.W.T., Canada. A total of 53 taxa from 33 genera were identified, 27 from leaves and litter and 46 from soil, using soil-washing and plating as isolation methods. The predominant fungi on leaves and litter of Carex stans and Dryas integrifolia were sterile fungi, associated with Cladosporiuin, Phoma herbarum. Penicillium spp., and yeasts. Sterile fungi, Penicillium spp. and Chrysosporium pannorum were predominant in raised beach soils, whereas a new species of Cylindrocarpon, sterile fungi. Penicillium, and Aspergillus species predominated in meadow soils. Use of direct observation methods showed that fungal biomass in meadow soils was much higher than in raised beach soils. In raised beach soils fungal biomass was heavily influenced by the distribution of cushion plants. In comparison with other tundra regions, the Truelove Lowland appears to have a moderately rich mycoflora, containing taxa common both in temperate regions and in other tundra soils. Total fungal biomass in Truelove Lowland soils was found to be low in comparison with many tundra regions.
Ultrastructural development of merosporangia in the mycoparasite Piptocephalis indica
Authors: Baker Karen K.
Published: November 2007

Transmission and scanning electron microscopy were used to study the ultrastructural development of merosporangia of Piptocephalis indica. Merosporangial branches were initiated from heart-shaped basal-spore initials on dichotomously branched sporangiophores. After elongation, spores were cleaved out of the merosporangial protoplast by simultaneous invagination of the plasmalemma. The plasmalemmal invaginations fused at the center of the merosporangium and delimited a varying number of more or less equal-sized spores in a single row. At maturity. spores had an inner, electron-transparent wall layer and an outer, electron-opaque wall layer. Mature spores possessed scars at each end with the basal spore having scars at each point of merosporangial disarticulation. Fertile branches were highly vacuolated at the time of spore detachment. Development of merosporangiospores in P. indica is similar to that in Syncephalis sphaerica at the early cleavage stages with some differences evident at postcleavage.
Interpretations of determination and canalisation of stamen development in a tomato mutant
Authors: Sawhney V. K. , Greyson R. I.
Published: November 2007

Floral buds of different sizes of the single-gene recessive mutant stamenless-2 (sl2/sl2) of tomato were treated with gibberellic acid (GA3) and the development of staminal features in each bud was followed. The results show that the application of GA3 to buds with stamen primordia at the early stages of initiation (up to 0.1 mm in length) induced the formation of normal-looking stamens. However, with a progressive increase in stamen size, less and less of the normal stamen features were produced following the GA3 treatment. Ultimately, buds with stamen primordia 0.8 mm long or longer failed to respond to GA3 and produced all the mutant characteristics. These results are discussed in terms of Waddington's concept of “determination” and “canalisation” of development.
Factors affecting perithecial production in Gibberella (Fusarium) tricincta
Authors: El-Gholl N. E. , Schoulties C. L. , Ridings W. H.
Published: November 2007

Three pigmentation types (brown, red, and white) of Fusarium tricinctum (Corda) Sacc. were observed when an isolated mass culture from leaf spots on English ivy (Hedera helix L.) was single spored. Perithecia of the heterothallic fungus Gibberella tricincta El-Gholl were produced at 20 and 27 °C on stem pieces of Cynodon dactylan Pers. resting on water agar, under 12-h alternating light and dark when certain pigmentation types were paired. Pairing of red and brown pigmentation types yielded significantly (P < 0.05) more perithecia than red and white pairings at 20 and 27 °C. Perithecia were formed only in combinations of red with brown or white pigmentation types. In both sets of pairings, significantly (P < 0.05) more perithecia were produced at 27 than at 20 °C. No perithecia were formed in constant darkness. Occasionally, the red pigmentation type became white after subsequent transfers and never reverted to the red pigmentation on various media and failed to produce perithecia with any pigmentation type. Continuous darkness slightly favored red pigment formation over continuous light as detected by the Munsell color codes. Increasing temperatures from 20 to 32 °C decreased the colony growth diameter of the red-pigmented cultural type. At 32 °C a change in hue was noted with corresponding changes in color codes. Red mycelial pigmentation was intensified by the addition of copper, iron, manganese, and zinc to a basal medium. The addition of 0.1% yeast extract favored mycelial development and caused a more pronounced red mycelial pigmentation in the presence of heavy metals.
Ultrastructure of teliospore formation in the rust fungus Puccinia podophylli
Authors: Mims Charles W. , Thurston E. Laurence
Published: November 2007

Teliospore initials of Puccinia podophylli develop from binucleate sporogenous cells lining the base of the telium. The teliospores are formed in basically the same fashion as those of other rusts that have been examined at the ultrastructural level. The long, straight or slightly curved spines present on mature teliospores initially develop as slight bulges or protrusions on the spore surface. The spore wall in such a region then evaginates to form a slender spine that is initially filled with cytoplasm. The cytoplasmic material is then progressively excluded from the tip of the spine as a result of the thickening of the spine wall. Mature teliospores of P. podophylli possess a wall consisting of a thick, outer, electron-dense layer in which stratification is only rarely visible and an inner thinner, less electron-dense layer.
A taxonomic study of Stipa nelsonii (Poaceae) with a key distinguishing it from related taxa in western North America
Authors: Barkworth Mary E. , McNeill J. , Maze Jack
Published: November 2007

Stipa nelsonii, more commonly but incorrectly known as S. Columbiana, is a wide ranging species of western North America, characterized by a short, pubescent palea and a hirtellous awn. Initial numerical analyses, using unweighted morphological data, suggested that three infraspecific taxa existed but with different methods of analysis there was a disturbing instability in the placement of certain operational taxonomic units (OTUs), including those based on the holotype of S. williamsii. Because replicate OTUs were incorporated in the sample, a character weighting, based on the relative constancy of character states within replicate pairs, was applied. The particular weighting function adopted utilized the added component of variance between groups, i.e., between the replicate pairs. Numerical analyses based on the weighted data proved to be stable with respect to all the OTUs. They suggested recognition of three infraspecific taxa. Keys to these taxa were devised and applied to about 400 additional specimens allowing the geographical and ecological distributions of the suggested taxa to be examined. The combined morphological and distributional studies suggest that S. nelsonii comprises two subspecies: subsp. nelsonii and subsp. dorei. Two varieties can be recognized in subsp. nelsonii: var. nelsonii centered in the intermountain region of the United States and var. longiaristata centered in eastern Washington. The range of subsp. dorei extends from southern Yukon to California and eastward to the Saskatchewan–Manitoba border. A key to the infraspecific taxa of S. nelsonii and to related taxa of western North America is included, as well as descriptions and distribution maps of the infraspecific taxa recognized in S. nelsonii.
The occurrence and ontogeny of transfer cells associated with lateral roots and root nodules in Leguminosae
Authors: Newcomb William , Peterson R. L.
Published: November 2007

Xylem parenchyma transfer cells are present in the stele of the root tissue adjacent to emergent effective root nodules of garden pea (Pisum sativum), red kidney bean (Phaseolus vulgaris), broad bean (Vicia faba), soybean (Glycine max), and mung bean (Vigna radiata), two types of ineffective pea nodules, and emergent lateral roots of pea. The xylem parenchyma transfer cells contain many polyribosomes and mitochondria near the wall ingrowths which are located adjacent to pits in the xylem elements. Pericycle transfer cells also occur in the three types of pea nodules. In effective pea nodules wall ingrowths begin to form in the pericycle cells 5 days after inoculation with Rhizobium leguminosarum; at this stage rhizobia are only present in the root hair but the cortical cells have enlarged and some have undergone mitosis. The wall ingrowths begin to form in the xylem parenchyma cells 7–8 days after inoculation or the approximate time that rhizobia begin to be released from the infection thread. In both instances the wall ingrowths begin to form before the onset of dinitrogen reduction although previous workers have suggested that a flux of nitrogenous compounds (containing fixed N) induces their formation. The development of wall ingrowths in ineffective pea nodules also occurs independently of nitrogen fixation. Similarly, the wall ingrowths located near soybean nodules also begin to develop before the onset of nitrogen fixation.
Electron microscopy of susceptible and resistant near-isogenic (sr6/Sr6) lines of wheat infected by Puccinia graminis tritici. III. Ultrastructure of incompatible interact
Authors: Harder D. E. , Samborski D. J. , Rohringer R. , Rimmer S. R. , Kim W. K. , Chong J.
Published: November 2007

The interaction between avirulent wheat stem rust and wheat mesophyll cells containing the temperature-sensitive Sr6 gene for stem rust resistance was studied by electron microscopy. Mesophyll cells that were invaded at 26 °C (conditioning compatibility) did not develop any signs of incompatibility after they were transferred to 19 °C, at which temperature incompatibility is normally expressed. In host tissue that appeared to be invaded after the change from 26 to 19 °C, the early ultrastructural symptoms of incompatibility were a more electron-dense and often perforated invaginated host plasmalemma, disruptions of the noninvaginated host plasmalemma, vacuolation of the cytoplasm, and accumulations of electron-dense material along the membranes of the vacuoles. At later stages in the development of incompatible interactions, the electron-dense accumulations along the vacuole membranes increased in size and occurred along chloroplast and mitochondrial membranes. Eventually, the entire protoplasts were electron dense and collapsed. In haustoria and haustorial mother cells, incompatibility was usually expressed by a uniform increase in electron density of the cytoplasm. In the Sr6/P6 interaction at 19 °C, host cell necrosis was not always accompanied by fungal necrosis or vice versa. In Sr5/P5 interactions, which were examined for comparison, the intracellular symptoms of incompatibility were similar to those of the Sr6/P6 interactions.
Vegetation–soil relationships along a spruce forest transect in interior Alaska
Authors: Dyrness C. T. , Grigal D. F.
Published: November 2007

Five distinct forest communities were recognized along a 3-km transect. These are, listed in order of decreasing elevation: (i) open black spruce/feathermoss - Cladonia, (ii) closed black spruce/feathermoss, (iii) open black spruce/Sphagnum, (iv) black spruce woodland/Eriophorum, and (v) white spruce/alder/Calamagrostis (restricted to a narrow band adjacent to a stream). Several techniques of ordination were used to recognize these five forest communities plus two intergrades: (open black spruce/feathermoss - Cladonia) - (Sphagnum) and open black spruce/Sphagnum - woodland/Eriophorum.The distribution of two-thirds of the plant species was highly correlated with vegetation–slope zones. Results of the fit of Gaussian curves also suggest that vegetation boundaries were well placed. The distribution of the four soil series in the area was well correlated with vegetation–slope zones: three were limited to one zone each. Permafrost, absent from the soil on the ridgetop and upper slope, was generally within 40 to 50 cm of the surface elsewhere and tended to be at shallower depths as elevation decreased. The most striking differences in forest floor properties were found in the white spruce zone compared with the six black spruce dominated zones. The white spruce forest floor was markedly thinner and had higher levels of nutrients. In the six black spruce dominated zones, forest floor thickness and concentrations of N and Mg tended to increase with distance downslope, and P and K decreased.
Entomophthora canadensis n.sp., a fungus pathogenic on the woolly pine needle aphid, Schizolachnus piniradiatae
Authors: MacLeod D. M. , Tyrrell D. , Soper R. S.
Published: November 2007

Entomophthora canadensis n. sp. is described and illustrated, and its morphological development traced. The new species differs from all other species of the genus, by its distinctively shaped conidia, long–elliptical to nearly cylindrical, average 25.0 μm × 10.0 μm, and its ornamented azygospores, verruculose to lightly rugulose, average 34.0 μm diameter. It is compared with E. aphidis, within which it has been included, and E. sphaerosperma, the species it most closely resembles.Entomophthora canadensis is currently known only from populations of the aphid Schizolachnus piniradiatae, in red pine plantations in Ontario, Canada.
Sexual reproduction of Larix occidentalis
Authors: Owens John N. , Molder Marje
Published: November 2007

Pollen-cone and seed-cone buds broke dormancy about 2 weeks before vegetative buds on the same tree. Pollen mother cells, which had over-wintered at pachytene or the diffuse stage of meiosis, resumed meiosis and tetrads of microspores were formed by mid-March. Wingless five-celled mature pollen developed by mid-to late April when pollination occurred.When development resumed after dormancy a ring of meristematic tissue formed the integument around the nucellus. The integument tip developed a short abaxial tip and a large adaxial lobe on which developed numerous long stigmatic hairs. A slit-like micropyle remained between the two lips. Several pollen grains usually adhered to the stigmatic hairs and then the two lips grew into the micropyle, engulfing the pollen. No pollination drop was observed. Within the micropylar canal, pollen greatly elongated then formed a pollen tube when the elongated pollen contacted the nucellus.Megaspore mother cells underwent meiosis at the time of pollination. Female gametophyte development, which was the same as in most other members of the Pinaceae, was completed in early June and two to five archegonia were formed. Fertilization occurred in early June, 6 to 8 weeks after pollination. A 16-celled proembryo developed. Simple polyembryony was common but cleavage polyembryony was not observed. Embryo development was similar to other members of the Pinaceae. Embryos and seeds were mature by mid-August.Normal appearing but inviable seed is common in L. occidentalis because the ovule is fully enlarged and the seed coat well developed at fertilization. Inviable seed commonly resulted from the absence of pollination, inviable pollen, lack of fertilization, later ovule abortion, or embryo abortion, primarily during early embryonic stages. Flat empty seed also occurred and resulted from abortion of the megaspore mother cell or early female gametophyte.
Neighbour relationships in grass–legume communities. III. Development of pattern and association in artificial communities
Authors: Turkington Roy , Cavers Paul B.
Published: November 2007

Early stages in the evolution of three artificial grass–legume communities were monitored by tracing the development of pattern and association, and percentage cover, among the constituent legumes. The results show that patterns and associations among the legumes changed rapidly and were influenced by the presence of grasses. Even though the percentage cover of each legume was only slightly affected by the presence of grasses, the legumes tended to be more evenly distributed when grasses were present than when they were absent. This had a small limiting effect on the rates of formation of species associations. When grasses were absent, the legumes formed more intense clumps. This suggests that the presence of grasses slows down the rate of clump formation in legumes and hinders the rate of development of associations. Another effect of the grasses was to induce positive associations between the legumes; when grasses were absent, the legumes were negatively associated.
Neighbour relationships in grass–legume communities. IV. Fine scale biotic differentiation
Authors: Turkington Roy
Published: November 2007

Ramets of Medicago sativa L., M. Iupulina L., and Trifolium repens L. were sampled from 10-year-old fields of Bromus inermis Leyss., Phleum pratense L., and Dactylis glomerata L. The ramets were multiplied and transplanted into artificial swards in all combinations of legumes and site of origin. Differences in "performance" (in terms of dry weights and number of survivors) were shown. The most striking effect was that the number of survivors of T. repens and M. sativa (and dry weight of T. repens) was greatest when the species was transplanted back into swards of the grass species from which they had been sampled. This trend is not applicable to dry weights of M. sativa, but an alternative trend is clearly demonstrated.In a second experiment, ramets of M. sativa were sampled from 1-, 3-, and 10-year-old fields of B. inermis, P. pratense, and D. glomerata and treated as above. The most striking effect is that the performance monitored in experiment 1 may be seen developing through the 1- and 3-year-old stages, demonstrating that the microcoevolutionary processes operating within a community are rapid events.
The effect of crude oil on the morphology of the green flagellate Chlamydomonas angulosa
Authors: Soto C. , Hutchinson T. C. , Hellebust J. A. , Sheath R. G.
Published: November 2007

The morphological changes of Chlamydomonas angulosa induced by treatment with an aqueous crude oil extract (ACOE) have been studied and compared with normal cells in the exponential phase of growth. Observations of oil-treated cells under the light microscope showed an effect on flagellar length and on motility, an increased activity of the contractile vacuoles, and an increase in granulations. Cells so treated become surrounded by a transparent envelope. By electron microscopy, the progression of ultrastructural changes has been followed. These changes include: a widened space between the cell wall and the plasmalemma; distorted and disorganized chloroplast lamellae; a decrease in density of the osmiophilic granules; and the presence of electron-dense deposits inside the cytoplasmic vacuoles. Cells were found to possess the ability to recover from the above abnormalities within an 8-day incubation period. Such a recovery corresponds to resumption of motility, capacity for growth, and photosynthesis, as described in other work. Based both on appearance, and on comparisons with bacterial, fungal studies, and cytochemical studies, it is suggested that the osmiophilic granules are lipid in nature and may act as a hydrocarbon sink. A self-cleansing mechanism is also suggested for these granules.
Turions and dormancy states in Utricularia vulgaris
Authors: Winston Robert D. , Gorham Paul R.
Published: November 2007

Phenology and states of dormancy of Utricularia vulgaris were studied using plants and turions collected at intervals throughout the growing season of 1977 from a shallow eutrophic pond in central Alberta located at 53°25′ N, 113°46′ W. States of dormancy and the effects of photoperiod and temperature were determined by the potential for sprouting and subsequent apical growth under long-day (18 h, 20 °C), short-day (12 h, 20 °C), and high-temperature (16 h, 30 °C) conditions, with and without varying periods of chilling at 2–3 °C. Physiological changes associated with different states of dormancy such as frost hardiness, starch content, and dark respiration were also investigated. Turions were formed 1 month after summer solstice and entered a state of innate dormancy during which only a high-temperature treatment at 30 °C would induce sprouting. Plants from innately dormant turions that were forced to sprout and were then cultured at 20 °C invariably reentered dormancy by the production of new turions. Turions collected in the late stages of innate dormancy could withstand −8 °C but not −12 °C. As temperatures dropped and ice cover became continuous, turions entered an imposed state of dormancy during which immediate sprouting and continued vegetative growth occurred under all conditions. Starch content reached a maximum of 49 mg g−1 fresh weight during early innate dormancy and declined steadily thereafter. Dark respiration in response to temperature of plants obtained from turions collected during innate and imposed dormancy states differed above 25 °C but was similar below.
Effect of fire on a Symphoricarpos occidentalis shrub community in central Alberta
Authors: Anderson Murray L. , Bailey Arthur W.
Published: November 2007

Spring fires were conducted in Symphoricarpos occidentalis Hook, stands to determine the effect of fire on the shrub and associated species. The canopy cover of Symphoricarpos had recovered to the level of unburned stands 3 months after fire. Stem density increased three to five times in the first 3 months and then gradually declined during the 2nd and 3rd year. Rubus strigosus increased in cover and stem density when burned and remained at higher levels for the 3 years studied. Forbs increased after fire with the cover of most annuals peaking the first growing season while perennials maintained a higher cover. The density of woody stems and coverage of the shrub, perennial forb, and grass and sedge groups continued to be higher 3 years after burning. There were substantial changes in one or more of frequency, cover, or density of major species.
The development of the fungal sheath on Cistus incanus short roots
Authors: Fusconi Anna
Published: November 2007

Sheath development of mycorrhizae of Cistus incanus L. ssp. incanus + Tuber melanosporum Vitt. synthesized under gnotobiotic conditions was studied by anatomical and ultrastructural techniques. Root systems examined at different times after inoculation exhibited short lateral roots which could be categorized as follows: (i) uninfected; (ii) with hyphae in the dead outer root cap cells; (iii) with developed sheaths. In the last case the inner hyphae of the sheath penetrated through remains of dead root cap cells which were trapped in the inner sheath. Remains of root cells were also found in the outer sheath. Growth of hyphae into the dead layers of the root cap leads to formation and development of the sheath.
Demography of Newfoundland populations of three Viola species
Authors: Newell Sandra J.
Published: November 2007

Demographic data were gathered on populations of Viola incognita Brainard, V. pallens (Banks) Brainard, and V. adunca Ait. in Newfoundland. Density, recruitment, and mortality varied within and among species; but most populations expanded tremendously during the 4-year study period. Increasing density in V. pallens and V. incognita populations resulted in decreasing mean size of ramets. Density effects on plant size in V. adunca were obscured by the addition of many small seedlings to the populations. Seedling density and survivorship were relatively high, and disturbance appears to play an important role in violet population dynamics. Relative plant age (i.e., cohort) and plant size seldom were associated with plant survival over a 1-year period. An association between plant size and survival existed in V. adunca only because one-leaf plants had a higher mortality rate than plants with two or more leaves. Low survivorship was associated with reproduction in V. incognita, but no such association existed in the other species. Levels of herbivory were low, and herbivory and subsequent survival over 1 year were not associated.
A numerical analysis of chromatographic profiles in North American taxa of the fern genus Gymnocarpium
Authors: Pryer Kathleen M. , Britton Donald M. , McNeill John
Published: November 2007

As part of a systematic investigation of the genus Gymnocarpium in North America, a survey of chromatographic profiles in species and hybrids of the genus was initiated. It was established through cluster analysis and ordination of the phenolic data that morphologically distinguishable taxa of Gymnocarpium can be recognized by their chromatographic profiles alone. These data provide supportive evidence for the recognition of G. robertianum and G. jessoense ssp. parvulum as distinct taxa and for the hybrid status of G. × intermedium. They also suggest that, as currently circumscribed, G. jessoense ssp. jessoense is a heterogeneous taxon.
Three new species in the genus Chaetomium
Authors: Carter A.
Published: November 2007

Three new Chaetomium species are described and illustrated. Chaetomium variostiolatum is recognized by the production of both ostiolate and nonostiolate ascomata. Chaetomium serpentinum is similar to C. atrobrunneum but can be distinguished by the smaller, ellipsoidal ascospores. Chaetomium hyaloperidium is characterized by the colourless peridium of the ascoma and bilaterally flattened ascospores. All three species are described in culture.
Fine structure of conidiogenesis in the mosquito pathogen Culicinomyces clavosporus (Deuteromycotina)
Authors: Inmann III A. O. , Bland C. E.
Published: November 2007

Conidiogenesis in Culicinomyces clavosporus Couch, Romney, and Rao (Deuteromycotina) is initiated with the growth of conidiogenous cells from vegetative hyphae. Formation of the primary conidium itself begins with a conidial initial which grows through the bilaminar wall at the tip of the conidiogenous cell, wall remnants of the conidiogenous cell often collapsing to form a collarette at the base of conidia. This factor, in addition to the fixed conidiogenous locus, shows that the conidiogenous cell is a phialide. As the conidial initial enlarges, a bilaminar well is synthesized around the cell, and cytoplasmic organelles migrate through the neck of the phialide into the initial. Once the conidium is mature, a septum is formed across the open neck of the phialide and two organelles (dense-core vesicles and autophagosomes), unique to conidia, become evident. The mode of development is enteroblastic–phialidic; Culicinomyces clavosporus is placed therefore in section IVB of the Hughes–Tubaki–Barron classification scheme described by B. Kendrick for the Deuteromycotina.
Etiology of grape crown gall in Ontario
Authors: Dhanvantari B. N.
Published: November 2007

Crown gall was found mostly on vinifera grape (Vitis vinifera L.) cultivars in Ontario vineyards. The galls were usually small and aggregated along the trunk and cane; large woody galls were less common. Vines affected by crown gall died back in 3–4 years after planting. All the nine strains of Agrobacterium tumefaciens (Smith and Townsend) Conn isolated from galls corresponded to biotype 3 in determinative tests and were pathogenic on Datura, tobacco, tomato, and sunflower plants. Eight strains were sensitive to agrocin 84 on amended Stonier's medium. They were suppressed if inoculation was preceded 6 h earlier by Agrobacterium radiobacter strain K84 at wound sites on Datura and tomato plants.
IMPROVEMENT OF RADIOSENSITIVE LIQUID-CORE MICROCAPSULES BY YTTRIUM POLYMERIZATION
Authors: HARADA S. , EHARA S. , ISHII K. , YAMAZAKI H. , MATSUYAMA S. , KAMIYA T. , SAKAI T. , ARAKAWA K. , SATO T. , OIKAWA S.
Published: November 2007

Microcapsules comprising alginate and hyaluronic acid that can be decomposed by radiation are under development. Previously, we observed that radiation efficiently decomposes microcapsules comprising alginate and hyaluronic acid in the ratio 2:1 by weight. In this study, Yttrium ( Y ) was added to these microcapsules to improve their decomposition by radiation.

Hyaluronic acid solutions (0.1% weight/volume) were mixed into 0.2% alginate solution, and carboplatin (0.2 mmol) was added; the resultant was used for capsule preparation. Capsules were prepared by spraying the material into mixtures of 4.34% CaCl 2 solution supplemented with Y at final concentrations from 0 to 1.0 × 10−2%.

These capsules were irradiated by a single dose of 0.5, 1.0, 1.5, or 2 Gy with 60Co γ-rays. Immediately after irradiation, we observed the release of the core contents of the microcapsule using a micro Particle Induced X-ray Emission (PIXE) camera.

The mean diameter of the microcapsules was 37.3 ± 7.8 μm . Maximum content of radiation-induced release was observed for liquid-core microcapsules prepared by polymerization in a 4.34% CaCl 2 solution supplemented with 5.5 × 10−3% Y .
FORMAL SPECIFICATION APPROACH OF ROLE DYNAMICS IN AGENT ORGANISATIONS: APPLICATION TO THE SATISFACTION-ALTRUISM MODEL
Authors: HILAIRE VINCENT , GRUER PABLO , KOUKAM ABDER , SIMONIN OLIVIER
Published: November 2007

This article deals with the problem of dynamic role-playing in Multi-Agent organisations. The approach presented uses a formal specification notation and is based upon a formal framework which defines the concepts of role, interaction and organisation. Within this framework the problem of dynamic role-playing specification is related to the merging of specifications. The formal notation used composes Object-Z and Statecharts. The main features of this approach are: enough expressive power to represent Multi-Agents dynamic aspects, tools for specification analysis and mechanisms allowing the refinement of a high level specification into a low level specification which can be easily implemented. The last part of this paper presents an application with the specification of a reactive and cooperative MAS model named Satisfaction Altruism. An analysis of the specification validates the agents' behaviours.
PROPERTY (FA) AND LATTICES IN SU(2,1)
Authors: STOVER MATTHEW
Published: November 2007

In this paper we consider Property (FA) for lattices in SU(2,1). First, we prove that [Formula: see text] has Property (FA). We then prove that the arithmetic lattices in SU(2,1) of second type arising from congruence subgroups studied by Rapoport–Zink and Rogawski cannot split as a nontrivial free product with amalgamation; one such example is Mumford's fake projective plane. In fact, we prove that the fundamental group of any fake projective plane has Property (FA).
ENDOMORPHISMS OF DISTRIBUTIVE LATTICES WITH A QUANTIFIER
Authors: ADAMS M. E. , DZIOBIAK W.
Published: November 2007

Let V be a non-trivial variety of bounded distributive lattices with a quantifier, as introduced by Cignoli in [7]. It is shown that if V does not contain the 4-element bounded Boolean lattice with a simple quantifier, then V contains non-isomorphic algebras with isomorphic endomorphism monoids, but there are always at most two such algebras. Further, it is shown that if V contains the 4-element bounded Boolean lattice with a simple quantifier, then it is finite-to-finite universal (in the categorical sense) and, as a consequence, for any monoid M, there exists a proper class of non-isomorphic algebras in V for which the endomorphism monoid of every member is isomorphic to M.
A NEW METHOD IN THE FINITE BASIS PROBLEM WITH APPLICATIONS TO RANK 2 TRANSFORMATION SEMIGROUPS
Authors: MASHEVITZKY G.
Published: November 2007

We prove that the semigroup of all transformations of a 3-element set with rank at most 2 does not have a finite basis of identities. This gives a negative answer to a question of Shevrin and Volkov. It is worthwhile to notice that the semigroup of transformations with rank at most 2 of an n-element set, where n > 4, has a finite basis of identities. A new method of constructing finite non-finitely based semigroups is developed.
DYNAMICAL EVOLUTION OF ROTATING ACCRETION USING DIFFERENT BOUNDARY CONDITIONS: STATE AFTER STABLE ACCRETION DISK CREATED
Authors: DÖNMEZ ORHAN
Published: November 2007

The 2D time-dependent solution of the thin and stable accretion disk with two-armed spiral shock waves in a closed binary system have been presented on the equatorial plane around the Schwarzschild black hole in Donmez (2004).2 The subject of this paper is to study the influence of two different boundary conditions, far away from a black hole called the outer boundary, on an accretion disk around the black hole during the time evolution. We have started with a stable accretion disk after the point where two-armed spiral shock waves were created (Donmez, 2004).2 The initial data which is also called the freezing boundary is used as a first boundary condition. As a second one, we use the outflow boundary condition. In both cases, the accretion disk is created and gases on the disk made closed trajectories. As a stable tori close to the black hole is created by using the first boundary, freezing condition, which has a ~10M radius where M is the mass of black hole, and the other boundary, outflow, creates stable two-armed spiral shock waves. The last stable circular orbit around the Schwarzschild black hole for this type of accretion disk is located around 11M in the case of the freezing boundary condition. The results of these simulations show that the tori and spiral shock waves are created in each case using freezing and the outflow boundary, respectively, and it also suggests that spiral waves are a robust feature of accretion disks in binary systems, and that these spiral shocks can indeed transfer the gravitational energy to the radiation energy observed by different X-ray satellites.
BOUNCING COSMOLOGICAL SOLUTIONS AND THEIR STABILITY
Authors: SETARE M. R. , DARABI F.
Published: November 2007

In the present paper, we consider the bouncing braneworld scenario, in which the bulk is given by a five-dimensional charged AdS black hole space–time with matter field confined in a D3 brane. Then, we study the stability of solutions with respect to homogeneous and isotropic perturbations. Specifically, the AdS black hole with zero ADM mass and charge, and open horizon is an attractor, while the charged AdS black hole with zero ADM mass and flat horizon, is a repeller.
PARAMETRIZATION OF THE DARK ENERGY EQUATION OF STATE
Authors: JOHRI VINOD B. , RATH P. K.
Published: November 2007

A comparative study of various parametrizations of the dark energy equation of state is made. Astrophysical constraints from LSS, CMB and BBN are laid down to test the physical viability and cosmological compatibility of these parametrizations. A critical evaluation of the four-index parametrizations reveals that Hannestad–Mörtsell as well as Lee parametrizations are simple and transparent in probing the evolution of the dark energy during the expansion history of the universe and they satisfy the LSS, CMB and BBN constraints on the dark energy density parameter.
VIBRATION OF INITIALLY STRESSED MICRO- AND NANO-BEAMS
Authors: WANG C. M. , ZHANG Y. Y. , KITIPORNCHAI S.
Published: November 2007

This paper is concerned with the vibration problem of initially stressed micro/nano-beams. The vibration problem is formulated on the basis of Eringen's nonlocal elasticity theory and the Timoshenko beam theory. The small scale effect is taken into consideration in the former theory while the effects of initial stress, transverse shear deformation and rotary inertia are accounted for in the latter theory. The governing equations and the boundary conditions are derived using the principle of virtual work. These equations are solved analytically for the vibration frequencies of micro/nano-beams with different initial stress values and boundary conditions. The effect of the initial stress on the fundamental frequency and vibration mode shape of the beam is investigated. The solutions obtained provide a better representation of the vibration behavior of initially stressed micro/nano-beams which are stubby and short, since the effects of small scale, transverse shear deformation and rotary inertia are significant and cannot be neglected.
DYNAMIC INFINITE ELEMENTS FOR SOIL-STRUCTURE INTERACTION ANALYSIS IN A LAYERED SOIL MEDIUM
Authors: YUN C. B. , CHANG S. H. , SEO C. G. , KIM J. M.
Published: November 2007

This paper presents the dynamic infinite element formulations that have been developed for soil-structure interaction analysis both in frequency domain and time domain by the present authors and our colleagues during the past 20 years. Axisymmetric, 2D and 3D layered half-space soil media were considered in the developments. The displacement shape functions of the infinite elements were established using approximate expressions of analytical solutions in frequency domain to represent the characteristics of multiple waves propagating into the unbounded outer domain of the media. The shape functions were determined in terms of the excitation frequency as well as the spatial and material characteristics of the far-field soil region. Thereby the element mass and stiffness matrices are frequency dependent. As for time domain analysis, the shape functions were further simplified to obtain closed-form frequency-dependent mass and stiffness matrices, which can analytically be transformed into time domain terms by the Fourier transform. The proposed infinite elements were verified using benchmark examples, which showed that the present formulations are very effective for the soil-structure interaction analysis either in frequency or in time domain. Example applications to actual soil-structure interaction problems are also given to demonstrate the capability and versatility of the present methodology.
ON MATRIX TYPE CORINGS, ALGEBRA COVERINGS AND ČECH COHOMOLOGY
Authors: SITARZ ANDRZEJ
Published: November 2007

We investigate a matrix-type coring associated to a complete covering of an algebra, its Amitsur complex and propose a definition for the related Čech cohomology relative to the covering.
A NEW ANTISYMMETRIC BILINEAR MAP FOR TYPE-I GAUGE THEORIES
Authors: ESPOSITO GIAMPIERO , STORNAIOLO COSIMO
Published: November 2007

In the case of gauge theories, which are ruled by an infinite-dimensional invariance group, various choices of antisymmetric bilinear maps on field functionals are indeed available. This paper proves first that, within this broad framework, the Peierls map (not yet the bracket) is a member of a larger family. At that stage, restriction to gauge-invariant functionals of the fields, with the associated Ward identities and geometric structure of the space of histories, make it possible to prove that the new map is indeed a Poisson bracket in the simple but relevant case of Maxwell theory. The building blocks are available for gauge theories only: vector fields that leave the action functional invariant; the invertible gauge-field operator; and the Green function of the ghost operator.
SYMMETRIES AND FIRST INTEGRALS FOR NON-VARIATIONAL EQUATIONS
Authors: FERRAIOLI DIEGO CATALANO , MORANDO PAOLA
Published: November 2007

For a class of exterior ideals, we present a method associating first integrals of the characteristic distributions to symmetries of the ideal. The method is applied, under some assumptions, to the study of first integrals of ordinary differential equations and first order partial differential equations as well as to the determination of first integrals for integrable distributions of vector fields.
Attosecond Electron Dynamics
Authors: Kling Matthias F. , Vrakking Marc J.J.
Published: November 2007

We describe the recent emergence of attosecond science, assessing the present state of the art and discussing several recent examples where attosecond electron dynamics has been studied in atomic and molecular systems. After introducing the generation and characterization of attosecond laser pulses, we describe the use of isolated attosecond pulses in a pump-probe experiment revealing the subcycle time dependence of a multiphoton ionization process and an experiment using the interference from a train of attosecond pulses to extract amplitude and phase information for electronic wave functions. We furthermore discuss experiments where ultrashort laser pulses with a reproducible waveform control electron dynamics in the D2+ molecular ion on attosecond timescales. Attosecond science is coming of age and presently is reaching a level of maturity and sophistication that allows detailed investigations of the role of multielectron dynamics in physics and chemistry.
U.S. Disparities in Health: Descriptions, Causes, and Mechanisms
Authors: Adler Nancy E. , Rehkopf David H.
Published: November 2007

Eliminating health disparities is a fundamental, though not always explicit, goal of public health research and practice. There is a burgeoning literature in this area, but a number of unresolved issues remain. These include the definition of what constitutes a disparity, the relationship of different bases of disadvantage, the ability to attribute cause from association, and the establishment of the mechanisms by which social disadvantage affects biological processes that get into the body, resulting in disease. We examine current definitions and empirical research on health disparities, particularly disparities associated with race/ethnicity and socioeconomic status, and discuss data structures and analytic strategies that allow causal inference about the health impacts of these and associated factors. We show that although health is consistently worse for individuals with few resources and for blacks as compared with whites, the extent of health disparities varies by outcome, time, and geographic location within the United States. Empirical work also demonstrates the importance of a joint consideration of race/ethnicity and social class. Finally, we discuss potential pathways, including exposure to chronic stress and resulting psychosocial and physiological responses to stress, that serve as mechanisms by which social disadvantage results in health disparities.