bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparative study of two groups of b proteins (pathogenesis related) from the intercellular fluid of Nicotiana leaf tissue infected by tobacco mosaic virus
Authors: Fortin Marc G. , Parent Jean-Guy , Asselin Alain
Published: June 2017

A time-course study showed that the major extracellular b (pathogenesis-related) proteins were detected approximately 37 h after tobacco mosaic virus infection of Nicotiana tabacum L. cv. Xanthi-nc tobacco leaf tissue. Silver staining of b1b2 and b3 proteins in native polyacrylamide gels required previous staining with Coomassie blue. Elution profiles of b4, b5, and b6b proteins from DEAE-Sephacel columns were similar to those of b1b2, and b3 proteins. Relationships among b proteins accumulating in the intercellular fluid of hypersensitive cv. Xanthi-nc tobacco leaves infected by tobacco mosaic virus were examined on the basis of serological relationships and by comparing peptide fragments. Results showed that b4, b5, and b6b proteins share common antigenic determinants and polypeptide fragments different from those shared by b1b2, and b3 proteins. Together with the close similarity of the molecular weights of the proteins within each group, these data suggest that at least two groups of related proteins are found in the intercellular fluid extracts of tobacco plants infected by tobacco mosaic virus. It is also shown that the antigenic determinants shared within the b4, b5, and b6b group are found with the same b proteins from systemically infected N. tabacum L. cv. Samsun and with some b proteins from N. sylvestris Speg. and Comes.
DNA relatedness among species of Geotrichum and Dipodascus
Authors: Guého Eveline , Tredick Joanne , Phaff Herman J.
Published: June 2017

The relatedness among species maintained as Geotrichum and Dipodascus (imperfect and perfect states) from their morphology, physiology, and ascomycetous characters was studied by techniques of nuclear genome comparison in combination with nuclear deoxyribonucleic acid base composition. Geotrichum fici exhibited 95% DNA base sequence complementarity with G. fragrans and was considered synonymous with G. fragrans. Two G. penicillatum strains exhibited 97–100% base sequence complementarity with G. klebahnii, and G. penicillatum is thus a later synonym of G. klebahnii. Geotrichum capitatum, G. klebahnii (which has priority over G. penicillatum), G. armillariae, and G. fragrans (which has priority over G. fici) can be considered as separate species and different from the type, G. candidum. Dipodascus geotrichum, which is considered the perfect state of G. candidum, showed a low but significant relationship to its proposed anamorph (about 45% relative binding of its DNA), but no other associations between perfect and imperfect forms could be detected. Our results suggest that in addition to current taxonomic criteria DNA comparisons also appear to be extremely valuable in making phylogenetic comparisons.
Nitrogen fixation in the high arctic tundra at Sarcpa Lake, Northwest Territories
Authors: Karagatzides Jim D. , Lewis Martin C. , Schulman Herbert M.
Published: June 2017

The acetylene reduction assay was used to examine biological nitrogen fixation in the high arctic tundra at Sarcpa Lake, Northwest Territories (68°32′ N, 83°19′ W). The highest rates of acetylene reduction (9.37 ± 3.19 μmol C2H4 m−2 h−1) were in habitats that had a high density of the legumes Oxytropis maydelliana, O. arctobia, and Astragalus alpinus. Nitrogen fixation in the wet soils along the shore of a small lake was similar (8.87 ± 4.35 μmol C2H4 m−2 h−1) because of the blue-green alga Nostoc, which associates with mosses. Free-living blue-green algae and lichens made insignificant contributions to the total nitrogen fixation budget because they were uncommon and fixed nitrogen at a slower rate. Nitrogen-fixing lichens in the area included Stereocaulon arenarium and S. rivulorum. It is concluded that legumes have a significant input to the biological nitrogen fixation budget at Sarcpa Lake.
Water availability and the comparative emergence of four conifer species
Authors: Thomas P. A. , Wein Ross W.
Published: June 2017

Some conifer species require shelter from direct sunlight to establish on surface charred organic matter. Since shelter slows the rate of soil drying, it has been postulated that the emergence of seedlings on such seedbeds is limited by soil moisture availability. In the greenhouse, the emergence of four species was observed from beds of soil watered at different frequencies. Compared with well-watered controls, emergence from infrequently watered seedbeds was higher in jack pine (Pinus banksiana Lamb.) than in eastern white pine (P. strobus L.) and lowest in black spruce (Picea mariana (Mill.) BSP.) and the balsam fir (Abies balsamea (L.) Mill.). This is in the same order as the ability to emerge without shelter on postfire seedbeds. Coping with fluctuating moisture availability was concluded to be a major factor in determining emergence on this harsh seedbed. Seeds were also germinated in solutions of polyethylene glycol 6000. These data, together with measurements of the resistance to and tolerance of water loss, suggest that eastern white pine succeeds because preemergent seedlings can tolerate desiccating conditions. Measurements of radicle elongation rates indicate that jack pine succeeds by evading periods of low water availability.
The ecology of Ramalina menziesii. I. Geographical variation in form
Authors: Larson D. W. , Matthes-Sears U. , Nash III T. H.
Published: June 2017

The lichen Ramalina menziesii Tayl. was studied and collected in all parts of its range from Baja California del Norte to the Queen Charlotte Islands to determine the pattern of morphological variation present and the possible factors controlling it. Various measures of morphological variation were considered, but one proved to be particularly useful in allowing a rapid determination of the form of the species found: the number of perforations present in 15 mm long net buds. When this measure was plotted against distance inland and latitude of origin, some clear trends emerged. Most conspicuous was that proximity to the coast was correlated with very few perforations per net. Increasing latitude was correlated with decreasing number of perforations per net. Increasing latitude was correlated with decreasing number of perforations, but north of central Oregon all the samples were strictly coastal. Concentrations of eluted Na+ and Cl− showed no significant effect related to latitude but a highly significant one related to distance inland. There were also significant relationships between morphological variation and both NaCl concentration and annual variation in temperature. There was some agreement between the distribution of different forms of this species and the patterns of annual precipitation. The distribution pattern of eight tree species that serve as substrate is related neither to the presence of R. menziesii nor to the form that it takes in the field.
The moss flora of the Gaspé Peninsula (Quebec, Canada): list of species and preliminary analysis
Authors: Belland René J. , Favreau Marc
Published: June 2017

Extensive field studies and evaluation of previously published reports reveal a moss flora of at least 310 species for the Gaspé Peninsula. Forty species are reported for the first time from the peninsula, and Brachythecium glaciale is new to Quebec. While the Gaspé flora cannot be considered a distinctive one within the Gulf of St. Lawrence region, the large number of rare species is significant. Their presence in the Gaspé can be attributed to the diverse geology and topography of the peninsula. The bulk of the moss flora is clearly of boreal affinity, but many species have temperate, montane, or arctic – alpine distributions. Of special interest is the large proportion of species with various types of disjunct distributions, either within eastern North America or to other parts of the world, especially western North America. Some patterns strongly support the idea of survival in refugia in the Gulf of St. Lawrence region during the last glaciation.
Vascular system of the floret of Phleum pratense
Authors: Pizzolato Thompson Demetrio
Published: June 2017

Two bundles occur in the rachilla at the floret base. The anterior bundle supplies the vascular tissue for the lemma median trace, and the posterior supplies that for its two extreme laterals. The intermediate laterals of the lemma connect at the anterior bundle, and the two palea traces join near the posterior bundle to the traces for the extreme lemma laterals. Near these connections sieve elements of the two rachilla bundles link, forming the lower component of the sieve-element plexus. The xylem discontinuity begins above the anterior bundle. An upper, circular component of the sieve-element plexus surrounds the discontinuity. The sieve elements of the lodicules join the anterior of the upper plexus. The upper plexus becomes trilobed as it merges with the stamen traces. Three pistil bundles including sieve elements and tracheary elements of the xylem discontinuity join the upper plexus. These pistil bundles unite into a circular pistil plexus surrounding the discontinuity. The anterior sieve tube of the pistil joins the anterior of the pistil plexus. Sieve elements emerge from the posterolateral portions of the plexus toward the styles and leave a placental bundle of sieve elements and tracheary elements of the xylem discontinuity in the pistil posterior.
The hybrid status of Spartina anglica (Poaceae). Enzymatic analysis of the species and of the presumed parents
Authors: Guenegou M. C. , Citharel J. , Levasseur J. E.
Published: June 2017

Three enzymatic systems were analysed in Spartina alterniflora Loisel., S. maritima (Curt.) Fernald, and S. anglica C. E. Hubbard, using samples gathered in the west of France. Examination of the acid phosphatases, esterases, and superoxide dismutases demonstrates certain analogies found in the three species. The hypothesis of a hybrid origin for S. anglica remains probable and is indeed enhanced by the isoforms of the esterases.
Croissance et tubérisation du radis (Raphanus sativus) selon la durée d'éclairement
Authors: Combe L. , Quetin Ph. , Decoux G.
Published: June 2017

Radish tuberization was studied with plants grown in a controlled-environment room at 19 °C day and night, with a daily light duration (radiant flux density, 600 μmol m−2 s−1 photosynthetically active radiations (PAR)) varying from 4 to 24 h at 2 h intervals. Day length did not seem to play a role in the initiation of tuberization: tuber thickening began after about 50 h of cumulative light exposure for all treatments. Moreover, two light treatments with the same daily photosynthetic balance, 8 h a day at high saturating irradiance (600 μmol m−2 s−1 PAR) and 16 h a day at low irradiance (200 μmol m−2 s−1 PAR), resulted in the same growth and tuberization regardless of day length. When the photoperiod is shorter than 7 h, it can modify leaf area, but for longer photoperiods, age is the main criterion determining foliage area. Cumulative light exposure determines the tuber dry matter to foliage dry matter ratio (tuberization index) if the day length is shorter than 16 h; if it is not, plant age alone determines the tuberization index. Day length has an effect on radish tuberization essentially because of its trophic action by photo-synthetic assimilate allocation to tuber thickening.
Similarities between the effects of aphid infestation and cytokinin application on dark respiration and plant growth of legumes
Authors: Hawkins C. D. B. , Whitecross M. I. , Aston M. J.
Published: June 2017

Cowpea (Vigna unguiculata (L.) Walp. cv. Caloona), broad bean (Vicia faba L. cv. Aquadulce), and garden pea (Pisum sativum L. cv. Victory Freezer) seedlings were infested with cowpea aphids (Aphis craccivora Koch) or pea aphids (Acyrthosiphon pisum (Harris)), both Homoptera: Aphididae, for 10 days and then infested host plant tissue was examined for foreign substances injected by the aphids. No foreign compound was detected in any of the aphid-infested plant tissues. Both aphid species were also assayed for plant growth substances, utilizing the epinastic response of tomato (Lycopersicon esculentum Mill. cv. Roma Teardrop) seedlings, and both aphid species contained plant growth substances in concentrations higher than plant physiological concentrations. Broad bean and pea seedlings were also treated with foliar and root applications of 6-benzylaminopurine to determine if there were any similarities in plant growth or respiratory responses, following aphid infestation or 6-benzylaminopurine treatment. Root respiration in 6-benzylaminopurine treated plants decreased while shoot respiration increased in a response analogous to that observed for aphid-infested tissue. However, the alternative respiratory pathway was engaged for all 6-benzylaminopurine treatments, whereas in aphid-infested plant roots and shoots it was not. Both 6-benzylaminopurine treated and aphid-infested plants displayed a loss of apical dominance. These data suggest that part of the physiological response of the plant to aphid feeding is induced by changes in the cytokinin to auxin ratio.
Annual differences in quality of leaf litter of aspen (Populus tremuloides) affecting rates of decomposition
Authors: Taylor Barry R. , Parkinson Dennis
Published: June 2017

Freshly fallen leaf litter was collected from a stand of trembling aspen (Populus tremuloides Michx.) in the Rocky Mountains of Alberta each autumn from 1981 through 1984. Leaves from 1981 and 1982 were yellow, waxy, and strong. Leaves from 1983 were pale brown and very brittle, and almost 1% of them suffered symmetrical deformities. Leaves from 1984 were composed of 80% yellow leaves and 20% green leaves, which apparently abscissed before senescence. Green and yellow 1984 leaves were distinctly different with respect to total (3 days) leaching loss, leachate conductivity, and proportions of ash, cellulose, and labile material. Green 1984 leaves contained twice as much nitrogen as yellow ones (13.1 vs. 6.5 mg∙g−1) and significantly more phosphorus (1.6 vs. 1.3 mg∙g−1). Leaves of different years varied widely with respect to leaf mass, water absorption rate, mass and conductivity of leachate, and proportions of cellulose, labiles, lignin, and ash, but there was no consistent ordering among years; leaves of different colouration (especially 1981 and 1983) were often physicochemically similar, while leaves identical in appearance were often chemically different. Small but significant differences in N and P concentrations among years were removed by 2 h leaching. Leaves of 1981 decomposing in laboratory microcosms at 26 °C lost less mass than either 1982 or 1983 leaves after 1 month, but not after 2 months. Ability of the cuticle to resist water absorption was probably responsible for the difference in initial decomposition rate.
A biochemical indicator of commitment to tracheid differentiation in Pinus contorta
Authors: Savidge Rodney Arthur
Published: June 2017

Quiescent 6-year-old lodgepole pine (Pinus contorta Dougl. var. latifolia) were transferred in midwinter from outdoors to warm, long-day greenhouse conditions. Vascular cambia from these trees were harvested on the day of transfer and weekly thereafter until xylem development became apparent. The stage of cambial reactivation in each tree was assessed by microscopy. Cambial extracts were then analyzed quantitatively by high-performance liquid chromatography (HPLC) at four ultraviolet wavelengths. A major HPLC peak, at 254 nm, was associated with radial expansion of cambial derivatives and increased markedly with secondary-wall formation and lignification in differentiating tracheids. The presence of this peak suggests a facile means for assessing commitment to tracheid differentiation in lodgepole pine.
A genetic study on Gracilaria sjoestedtii
Authors: Zhang Xuecheng , Meer John P. van der
Published: June 2017

In the present study on Gracilaria sjoestedtii, 41 mutants (40 pigmentation and 1 morphological) were isolated. These were characterized in a Mendelian analysis, which showed that 26 of the pigmentation variants are recessive nuclear mutations. The remaining 14 are cytoplasmic mutants having maternal inheritance and no detectable transmission through spermatia. A partial complementation analysis identified seven cistrons among the nuclear pigmentation mutants. Multiple alleles were encountered at five loci and apparent intragenic recombination was observed. No linkage between cistrons was found in recombination tests conducted thus far. Mitotic recombination leading to diploid gametes on tetrasporophytes was observed and used to construct triploid tetrasporophytes. The chromosome number of a wild-type clone of G. sjoestedtii was determined at meiosis as n = 29–30. Trivalent chromosomes were observed during meiosis in tetrasporophytes obtained by crossing female plants with tetrasporophytes. In culture tanks with flowing seawater, female gametophytes grew faster and appeared more suitable for vegetative propagation than male gametophytes and tetrasporophytes.
Morphological characterization of Armillaria ostoyae and Armillaria sinapina sp.nov.
Authors: Bérubé J. A. , Dessureault M.
Published: June 2017

In Quebec, the root rot fungus Armillaria mellea (Vahl: Fr.) Kummer in the broad sense was found to be composed of three intersterile groups or biological species by using mating tests with standard voucher strains. Monosporous cultures of our specimens were compatible with strains of groups I, V, and VI. Groups I and V corresponding to A. ostoyae (Romagn.) Herink and A. sinapina sp.nov., respectively, are described and their occurrence and ecology documented. Morphological characteristics of fruiting bodies and of vegetative isolates can be used to differentiate A. ostoyae, A. sinapina, and A. mellea s.str. Armillaria ostoyae and A. sinapina are mild pathogens or saprotrophs on declining trees or stumps, whereas A. mellea s.str. appears to be an aggressive pathogen.
Structure et ultrastructure de l'haustorium du Striga hermonthica, une scrophulariacée parasite du mil (Pennisetum typhoides)
Authors: Ba Amadou Tidiane
Published: June 2017

Striga hermonthica (Del.) Benth., (Scrophulariaceae) a parasite of pearl millet (Pennisetum typhoides (Burm.) Stapf and Hubb.), is attached to its host roots by suckers (also called haustoria). The anatomy and ultrastructure of the haustoria described in this study, including the cytology of such haustorial features as intrusive cells, intertracheidal parenchymatous cells, axial vascular core, hyalin tissue, and radial vascular system. Investigations with both electron and fluorescence microscopy did not disclose the presence of phloem. This lack is considered to be a common feature of the haustoria of parasitic Scrophulariaceae.
La variabilité morphologique des taxons marocains du genre Ornithogalum sous-genre Heliocharmos : une étude biométrique
Authors: Moret J. , Couderc H. , Gorenflot R. , Hubac J. M.
Published: June 2017

Taxa of the subgenus Heliocharmos Baker belonging to the genus Ornithogalum L. (Liliaceae) have been studied in Morocco from a biometric standpoint. It appears, from multidimensional analyses (principal component analysis and discriminant analysis), that it is not possible to recognize the existence of all the taxa reported by former authors. Two groups are morphologically distinct. The first corresponds to O. kochii Parl, and the second to O. algeriense Jord. and Fourr. The latter group includes all individuals that, according to Maire's Flora, can be related to O. comosum L., O. tenuifolium Guss., and O. umbellatum L. ssp. orthophyllum Maire and Weiller. Maire's separation of this group into three species seems artificial and the determination of the taxa seems incorrect. However, the populations of this group form two sets, one littoral and the other inland. These results, which are in agreement with data on karyology and reproduction biology, make it possible to revise this subgenus in Morocco. Three taxa are recognized: O. algeriense Jord. and Fourr. (=O. umbellatum L. ssp. orthophyllum Maire and Weiller) ssp. algeriense Moret ssp. nov., O. algeriense Jord. and Fourr. ssp. atlanticum Moret ssp. nov., and O. kochii Parl. A key to the various taxa and a map showing their distribution in Morocco are submitted. Key words: Ornithogalum, Heliocharmos, Liliaceae, Maroc, biosystematics, biometry. [Journal translation]
Le statut des Euphrasia borealis, E. nemorosa et E. stricta dans l'est de l'Amérique du Nord : une analyse numérique
Authors: Downie Stephen R. , Quintin Andrée , McNeill John
Published: June 2017

The taxonomic status of Euphrasia borealis, E. nemorosa, and E. stricta in eastern North America has been the subject of considerable controversy. A sample of 184 operational taxonomic units were scored for 58 morphological characters, and the resulting data matrix was subjected to cluster and principal component analyses. Two groups were recognized on the basis of bract and upper cauline leaf characters and designated as E. nemorosa and E. stricta. These two groups were then subjected to several discriminant analyses (stepwise, linear, and canonical) using quantitative data. The results do not support the recognition of E. borealis and E. nemorosa as separate taxa. These plants should be treated as a single species, for which the correct name is E. nemorosa. Euphrasia stricta is, however, morphologically distinct from E. nemorosa. Some geographic differentiation was observed between plants of E. nemorosa from Newfoundland and those from Quebec, but not enough to warrant the recognition of infraspecific taxa. No evidence of hybridization between E. nemorosa and E. stricta was found. Key words: Euphrasia borealis, Euphrasia nemorosa, Euphrasia stricta, numerical analysis, North America, hybridization.
Évolution récente d'une tourbière à palses (Québec subarctique) : analyse cartographique et dendrochronologique
Authors: Laprise Danielle , Payette Serge
Published: June 2017

During the past 100 years, palsa bogs located on the eastern coast of Hudson Bay have undergone major changes associated with global climatic warming of the northern hemisphere. The recent main developmental stages of palsas, collapse scars, and thermokarstic pools were reconstructed within a representative permafrost peatland located in the southern part of the forest–tundra, using detailed mapping and tree-ring analyses. Maps of the peatland in 1957, 1973, and 1983 indicate a 49% decrease of the total cover of palsas and collapse scars between 1957 and 1983 and a 44% increase of the thermokarstic pool surface. Degradation of the palsa bog was more pronounced between 1957 and 1973 than between 1973 and 1983. Tree-ring analysis of reaction wood on black spruce (Picea mariana (Mill.) BSP.) exposed to unstable peat substratum indicates that permafrost degradation, which began as early as 1880, increased markedly between 1930 and 1965. During the 19th century, the permafrost peatland was mainly composed of large peat plateaus, which subsequently disintegrated into residual palsas, collapse scars, and thermokarstic pools. In addition the increase in temperature during the 20th century, it seems that milder winters with heavier snowfalls promoted conditions conducive to permafrost degradation. The constantly increasing contrast in the microtopographic pattern of the peatland, resulting from the transformation of peat plateaus into smaller palsa units, created more snow cover on east and southeast palsa slopes, thus accelerating permafrost degradation. This autocatalytic process seems to have also played a role in some sections of the peatland with abundant thermokarstic pools, where major changes in drainage conditions have stimulated thermokarstic erosion.
Crown architecture of Larix laricina saplings: production and disposition of foliage and their simulation
Authors: Remphrey W. R. , Powell G. R.
Published: June 2017

In saplings of Larix laricina (Du Roi) K. Koch (tamarack), correlations between projected leaf area (PLA) and architectural variables such as shoot length and shoot age were incorporated into existing simulation models to estimate the distribution of PLA in the crown according to several spatial, temporal, and morphological parameters. After five generations of simulated shoot growth, PLA values ranged from 8.2 m2 for trees with short height growth increments (HGIs) and no syllepsis to 25.5 m2 for those with long HGIs and heavy syllepsis. Although PLA increased, the rate of increase declined over time. In early simulated generations, long-shoot PLA predominated. In the fifth simulated generation, short shoots bore about 75% of the PLA. There was a basipetal increase in PLA by HGI, but the relationship was nonlinear. In trees with syllepsis, sylleptic origin branches on individual HGIs carried more PLA than concomitant proleptic branches for 1 year but thereafter the proportions were reversed. Over successive generations, the contribution of different branch orders to the total PLA shifted from mostly first-order long shoots (including PLA on daughter short-shoot axes) to second-order shoots carrying more than 50% by year 5. Because of the short-shoot contribution, there was considerable PLA in all regions of the crown, although the greatest concentration was in lower regions of midconic zones. Simulated PLA index increased substantially with crown development. Trees with short HGIs had the greatest PLA index and those with long HGIs had the least.
C3and C4photosynthesis inCyperus(Cyperaceae) in temperate eastern North America
Authors: Li Mei-Rong , Wedin David A , Tieszen Larry L
Published: June 2017

All species in the genus Cyperus (Cyperaceae) that occur in temperate eastern North America were assigned to either the C3or C4photosynthetic pathway using leaf anatomical characteristics and stable carbon isotope ratios. Of the 39 species in the study area, 32 had C4photosynthesis while 7 had C3. The numbers of C3, C4, and total Cyperus species were significantly and positively correlated with both summer precipitation and mean annual temperature. However, the proportional abundance of C4species within Cyperus was not significantly related to either climatic variable. The highest Cyperus diversity was found on the Atlantic Coastal Plain, a pattern that remained after climatic differences between regions were accounted for. All the C3species and the majority of the C4species were restricted to wetlands or damp soil habitats; 13 of the 32 C4species occurred in dry, sandy habitats. Given that the C3pathway is ancestral in the genus Cyperus, it appears that C4photosynthesis evolved in a wetland context for this genus. We suggest that the high nitrogen use efficiency associated with the C4pathway is largely responsible for the evolution and ecological success of C4Cyperus species in infertile, temperate wetlands.Key words: C3and C4photosynthetic pathways, Cyperus, Cyperaceae, eastern North America, stable carbon isotopes.
Molecular diversity of ericoid mycorrhizal fungi
Authors: Monreal Marcia , Berch S M , Berbee Mary
Published: June 2017

Using restriction fragment length polymorphism (RFLP) patterns from two ribosomal internal transcribed spacers (ITS) and DNA sequences from ITS2, we characterized ericoid mycorrhizal fungal isolates from culture collections.With a synoptic key to RFLP patterns, we divided 34 mycorrhizal or root-associated isolates into 16 groups. RFLP patterns were identical when fungal specific primers were used to amplify DNA from pure fungal cultures and in vitro mycorrhizae. Sequence analysis clustered 23 of 24 mycorrhizal isolates into two larger groups: the Oidiodendron group and the Hymenoscyphus group. The Oidiodendron group included genetically uniform, conidiating fungi. The Hymenoscyphus group encompassed more diversity and included other discomycetes (Leotiales) as well as sterile, unidentifiable mycorrhizal isolates from four RFLP groups. Results from our field site on Vancouver Island, British Columbia, Canada, suggest that several ericoid mycorrhizal fungi can coexist in a single root of Gaultheria shallon Pursh and that our molecular data base is not yet complete. From sixty 3-mm root sections, we cultured four genetically different fungi that formed mycorrhizae in resynthesis experiments and sequence analysis showed that one of these differed from all previously known ericoid mycorrhizal fungi.
A comparative test of the predictive power of neighbourhood models in natural populations of Lasallia pustulata
Authors: Sletvold Nina , Hestmark Geir
Published: June 2017

Three different neighbourhood models were tested to predict individual performance in 50 natural populations of the saxicolous lichen Lasallia pustulata (L.) Mérat. Mean distance to neighbours was clearly the best predictor, accounting for most of the variation in 70% of the populations. In contrast a model based on the number of neighbours within a circle of fixed radius usually had the lowest predictive power. Polygon areas generated by Dirichlet tessellation had a predictive power slightly less than the nearest neighbour approach. The predictive power of all three neighbourhood models was significantly positively correlated, and the polygon and the nearest neighbour model was strongly so. The differences in predictive power are interpreted as reflecting the degree of realism included in the models. The nearest neighbour approach uses actual distances to neighbours, a fairly direct measure of degree of interference in crowded populations. Tessellation models use these distances to generate semi-empirical areas of influence. In contrast the circle model circumscribes a neighbourhood in an arbitrary and abstract manner, and only secondarily take into account the number of organisms within that area. Considering the comparative merits of the models, it is a paradox perhaps that the most frequently used model in previous studies has been the circle model.
Reproductive biology of leafy spurge (Euphorbia esula L.): breeding system analysis
Authors: Selbo Sarena M , Carmichael Jeffrey S
Published: June 2017

Leafy spurge (Euphorbia esula L.) represents a non-native, invasive weed that dominates many regions across North America. While many research efforts are aimed at controlling the growth and spread of this plant, relatively little is known about its breeding system. This study provides evidence that leafy spurge is self-compatible, with selfed plants producing roughly half as many seeds as outcrossed plants. Unpollinated flowers failed to set seed and thus preliminary tests for apomixis were negative. However, microscopic examination of pollinated flowers revealed that pollen tubes did not appear to enter ovules in either selfed or outcrossed flowers. Therefore, leafy spurge exhibits structural evidence that suggests pseudogamy may play a role in the reproductive strategies of this invasive weed.
Evaluating the potential of using 5-azacytidine as an epimutagen
Authors: Fieldes M A , Amyot L M
Published: June 2017

A number of early flowering lines were induced when 5-azacytidine was applied to germinating flax (Linum usitatissimum L.) seed. The genetics of these lines indicate that the induced changes are epigenetic and probably result from demethylation of the genomic DNA at loci that affect flowering age. Although the growth and development of three stable early flowering lines are altered and the percentage of filled seed was reduced in all three lines compared with controls, measures of seed productivity demonstrated that harvest index was unaffected in two of the lines. In the third, harvest index was lower than normal and both seed set per capsule and seed mass per 100 seed were reduced. Furthermore, six generations after induction this line began to display relatively high levels of polyembryony. The late appearance of this twinning and other aspects related to working with lines induced by 5-azacytidine and using 5-azacytidine as an epimutagen are discussed.
ESTIMATION OF AXIAL FRETTING FATIGUE LIFE AT ELEVATED TEMPERATURES USING CRITICAL DISTANCE THEORY
Authors: MAJZOOBI G. H. , AZHDARZADEH P.
Published: June 2017

Fretting fatigue life is traditionally estimated by experiment. The objective of this work is to introduce a special approach for estimation of axial fretting fatigue life at elevated temperatures from plain fatigue test based on the critical distance theory. The method uses Fatemi–Socie parameter as a multiaxial criterion to compute the stress multiaxiality on focus path. This method considers only elastic behavior for materials, and two characteristic diagrams are obtained from plain fatigue tests on two U-shaped and V-shaped notched specimens. The results showed reasonable agreement between the predictions by the proposed method and the experiments for ambient temperature. For elevated temperatures, the results indicated that the predicted fretting fatigue life was considerably overestimated in the low cycle fatigue (LCF) regime and underestimated in the high cycle fatigue (HCF) region with respect to experimental measurements. The reason for such discrepancy is believed to be due to the complex behavior of AL 7075-T6, which exhibits at elevated temperatures because of the problems such as aging, oxidation and reduction of strength.
An Original DEM Bearing Model with Electromechanical Coupling
Authors: Machado C. , Baudon S. , Guessasma M. , Bourny V. , Fortin J. , Bouzerar R. , Maier P.
Published: June 2017

We have developped an original 2D modeling of bearings by Discrete Element Method (DEM). The mechanical behavior and the dynamic of a bearing is well reproduced. An electromechanical coupling is introduced to provide monitoring solutions. In practice, the mechanical state in real-time is usually unknown and existing numerical methods are restricted. Electromechanical coupling seems to be able to indirectly measure the dynamic loading of the bearing. This behavior leads to the development of a new monitoring method based on electrical signatures. The study proposes an original method of simulating the bearings to correlate dynamic mechanical state with electrical responses, over time. The bearing is seen as a polydisperse granular chain where rolling elements and cage components interact with a Hertzian contact model. Moreover, rings (and housing) are also taken into account using a cohesive model. Indeed, while many studies have been conducted on bearing simulation using FEM and multibody approaches, this discrete approach gives relevant informations on physical phenomena in the contact interface. One of our objectives is to investigate the sensitivity of the electrical measurement due to typical mounting. The ability of DEM to describe accurately the mechanical state of a bearing has been established by means of a comparison with FEM, of load distributions in a static case. In dynamic, the consequences associated with the flexibility of the bearing mounting (rigid and elastic rings) are studied with mechanical stresses acting in rings and with the load distribution. Also, by accessing dynamic stresses, this modeling opens certain possibilities on studies of damage and wear by providing the history of contact.
The Effects of Fungicides on Human 3β-Hydroxysteroid Dehydrogenase 1 and Aromatase in Human Placental Cell Line JEG-3
Authors: Cao Shuyan , Ye Leping , Wu Ying , Mao Baiping , Chen Lanlan , Wang Xiudi , Huang Ping , Su Ying , Ge Ren-Shan
Published: June 2017

Placenta secretes a large amount of progesterone and estradiol, which are critical for maintaining pregnancy. In human placenta, 3β-hydroxysteroid dehydrogenase 1 (HSD3B1) catalyzes pregnenolone to form progesterone, and aromatase (CYP19A1) catalyzes testosterone into estradiol. Fungicides display antifungal activities and are widely used to prevent fungal infections in agricultural plants. These chemicals include azoles, such as tebuconazole (TEB), triadimefon (TRI), and vinclozolin (VCZ) or organotins, such as tributyltin (TBT) and tetrabutyltin (TTBT). Fungicides may disrupt the activities of these 2 enzymes. In the present study, we investigated the effects of these fungicides on steroid production in a human placental cell line JEG-3 and on HSD3B1 and CYP19A1 activities. Of all fungicides tested at 100 µmol/L, only TBT inhibited pregnenolone-mediated progesterone production in JEG-3 cells by over 50%. Except TTBT, all other 4 fungicides inhibited testosterone-mediated estradiol production by over 50%. TBT was a moderate HSD3B1 inhibitor with a half maximal inhibitory concentration (IC50) of 45.60 ± 0.12 µmol/L. When pregnenolone was used to determine the mode of inhibition, TBT was a competitive inhibitor of HSD3B1. The IC50 values of TEB, TRI, VCZ, and TBT for CYP19A1 were 56.84 ± 0.13, 58.73 ± 0.14, 57.42 ± 0.171, and 4.58 ± 0.048 µmol/L, respectively. TEB, TRI, and VCZ were noncompetitive inhibitors of CYP19A1, while TBT was a competitive inhibitor of this enzyme. Therefore, they are endocrine disruptors.
Relationships between psychological state, abuse, somatization and visceral pain sensitivity in irritable bowel syndrome
Authors: Grinsvall Cecilia , Törnblom Hans , Tack Jan , Van Oudenhove Lukas , Simrén Magnus
Published: June 2017

Background and objective

Psychological states may interfere with visceral sensitivity. Here we investigate associations between psychosocial factors and visceral sensitivity in irritable bowel syndrome (IBS).

Methods

Two IBS patient cohorts (Cohort 1: n  = 231, Rome II; Cohort 2: n  = 141, Rome III) underwent rectal barostat testing, and completed questionnaires for anxiety, depression, somatization, and abuse. The associations between questionnaire measures and visceral sensitivity parameters were analyzed in three‐step general linear models (step1: demographic and abuse variables; step 2: anxiety and depression; step 3: somatization).

Results

Cohort 1. Pain threshold was positively associated with age and female gender, and negatively with adult sexual abuse and somatization. Pain referral area was negatively associated with age and positively with somatization and GI‐specific anxiety, the latter effect mediated by somatization. Cohort 2. Pain threshold was positively associated with age and male gender, and negatively with adult sexual abuse. Pain intensity ratings were positively associated with somatization, female gender and depression, the latter effect mediated by somatization.

Conclusion

Somatization is associated with most visceral sensitivity parameters, and mediates the effect of some psychological factors on visceral sensitivity. It may reflect a psychobiological sensitization process driving symptom generation in IBS. In addition, abuse history was found to independently affect some visceral sensitivity parameters.
Evaluation of Whole-Body-Vibration Among Tractor (41 kW) Drawn Subsoilers
Authors: Bandhiya Rajeshkumar , Jain Kundan
Published: June 2017

Whole-body-vibration can be say to that part of vibration which received by a person’s body, from the machine. Subsoiling is heavy draft farm operation so to know the effect of subsoiling on vibration, it needs documentation which helps to decide safe exposure limits in sense of duration of safe subsoilling hours. For study, three subsoilers as single tine straight shank subsoiler (S1), double tine straight shank subsoiler (S2), and double tine curved shank subsoiler (S3) at three different depths (20-25, 25-30, and 30-35 cm) performed subsoiling and evaluated the effect of subsoiling on different parameters as vibration, fuel consumption, wheel slip, draft, and soil disturbance area were observed and analyzed.
The vibration was increased as operating depth was increased. It was recorded maximum at depth of 30-35 cm (d3) for “X” direction as 0.296 m/s2, for “Y” direction as 0.284 m/s2, for “Z” direction as 0.431 m/s2, and for total acceleration (Ahv) as 0.451 m/s2. The vibration in “X” direction was increased 5.86 % and 11.64 %, in “Y” direction was increased 6.52 % and 12.42 %, in “Z” direction was increased 3.68 % and 8.11 %, and Ahv was increased 10.23 % and 13.59 %, for d2 and d3 depths compared to d1 depth.
On the other hand, the fuel consumption, wheel slip, and draft were found maximum for S2 subsoiler and minimum for S1 subsoiler. Soil disturbance area was observed maximum for S2 subsoiler and minimum for S1 subsoiler. Also same effect as vibration, the increased subsoiling depth resulted increased in these parameters. The safe exposure working hours were calculated as work with S1 subsoiler at the depths of d1, d2, and d3 were 8 h, 6 h, and 4 h respectively. Same as for S2 subsoiler were 4 hours at all depths and for S3 subsoiler it was calculated 4 to 6 hours. In conclusion, single tine subsoiler can be a better option for subsoiling. Only the soil disturbance area and field capacity becomes half as compared to double tine subsoilers.
Morphogenetic Responses in Anthurium Andreanum (Hort) Cultivars
Authors: Prakasha D. P. , Ramya G , Srinivasalu G. B
Published: June 2017

In this study, in vitro morphogenetic responses have been studied in popular Anthurium andreanum cultivars Tropical Red, Acropolis, Sun Glow, Esmeralda, Chaco, Pistachio, Neveda and Safari employing explants of various types and growth stages, through indirect organogenesis. Creamy and compact callus initiated in cut ends along the veins of Leaf lamina with mid rib (LLMR) and petiole with leaf (PL) explants of various cultivars in 30-120 days of inoculation, it was sub cultured and incubated in dark for proliferation. Leaf tip, candle and petioles did not show any kind of response, turned brown and died later. Explants from young pale green leaves with smooth structure showed early response in all cultivars. Callus proliferation rate was 3.0-5.0 times 30-35 days of incubation in various cultivars. Shoot bud initiation and elongation observed after 45-60 days incubation in dark. Number of shoot buds per explants ranged from 30-60 per explants and 8-10 buds attained 1.5-2.5 cm in height. Then, shoots were separated, inoculated in shoot elongation medium and incubated in light. Remaining callus was sub cultured in callus multiplication medium and incubated in dark. Callus and shoot multiplication ratio was 1-2 and 2.5-4.2 times respectively. Shoots attained 4-5.3 cm in height in 45-55 days, rooted and ready for hardening in 65-80 days. Rooted plantlets were hardened in 1:1 ratio soil rite and coco-peat mix in portrays, transferred to beds prepared with coconut coir-pith, 95% plants survived, appeared normal and flowered. In this paper, materials, methodology, results will be discussed.
Charity always begins at home
Authors: Garner Lynne
Published: June 2017

From an early age, we encourage children to share. So, exploring the theme of charity and giving is a good way to encourage them to think about how sharing can help others.
Cellular Automata Based Study of Spectral Signatures of Dal_Lake Infrared Imagery
Authors: Wani Shahi , Qadir Fasel
Published: June 2017

Among all the water bodies in Jammu & Kashmir Dal Lake has a peculiar significance due to its location in the heart of the capital city Srinagar. Historical studies over last fifteen hundred years indicate a continuous squeezing of the Lake due to different natural and manmade interventions. Over this long period, the governance of the land has passed through various wise and ugly human plans besides some slow natural processes. The mathematical modelling of such a dynamics is not an easy task because of the many intervening variables and the difficulty which implies their measurements. On the other hand, during the last decades, the use of Cellular Automata (CA) techniques to simulate the behaviour of linear or non-linear systems is becoming of great interest. This fact is mainly due to the fact that this approach depends largely on local relations and a series of rules instead of precise mathematical formulae. The infrared (IR) satellite imagery can be helpful in identifying the different areas of interest using CA as a tool of image processing. The study will not only separate the areas of interest but also pave a way towards a comprehensive study of all the identified zones using spectral signatures received from the continuous IR imagery of both pre-monsoon and post-monsoon periods in future.
Plastic Money Security Issues in India
Authors: Hooda Reena , Dhaka Deepak
Published: June 2017

The benefit of plastic money is its accessibility and acceptability with lightness than cash in wallet plus ready notion with the major problem of fraudsters who may exploit the rights of the genuine stakeholders. At present, the computing resources, communication technology, availability of the cards in competitive market are escalating India to be placed at the growing edge of popularity of plastic money. People after demonetization are intensely employing the technology; moreover it’s a step towards the digitalization of India. With increasing population of the smart phone users, people are more aware about the cautions needed to pursue while using P-cards. However as compare to the developed nations, in a land of villages- India, the problem become more perilous as there are petite infrastructural facility & literacy, high percentage of less skilled population, old customs and non-reach of the government facilities, spoiling the p-money applicability & security and digital India campaign.. Therefore, besides the plastic money rewards and contributions to the digitalization, present paper contributed towards a range of security issues in addition to technique to make money protected and reliable.
Survey on Packet Marking Algorithms for IP Traceback
Authors: Bhavani Y , Janaki V. , Sridevi R.
Published: June 2017

Distributed Denial of Service (DDoS) attack is an unavoidable attack. Among various attacks on the network, DDoS attacks are difficult to detect because of IP spoofing. The IP traceback is the only technique to identify DDoS attacks. The path affected by DDoS attack is identified by IP traceback approaches like Probabilistic Packet marking algorithm (PPM) and Deterministic Packet Marking algorithm (DPM). The PPM approach finds the complete attack path from victim to the source where as DPM finds only the source of the attacker. Using DPM algorithm finding the source of the attacker is difficult, if the router get compromised. Using PPM algorithm we construct the complete attack path, so the compromised router can be identified. In this paper, we review PPM and DPM techniques and compare the strengths and weaknesses of each proposal.
Between innocence and experience: Variations on Robert Landy’s Persona and Performance (1993)
Authors: Pitruzzella Salvo
Published: June 2017

In this article I explore the influence of Robert Landy’s concept of role upon my own vision of drama therapy. I recount how my encounter with his seminal book Persona and Performance (1993) provided me with guidance in my challenging quest. I propose that our innately human tendency
for relationships relies on an inner core which cannot be subsumed under the notion of ‘self’ but can be described in terms of an innate relational potentiality that drama therapy has the power to revive.
Addicted to crisis: Exploring the symptoms of an addicted work system using the lens of Role Theory
Authors: Levanas Danielle Bragg
Published: June 2017

Professionals working in mental health care and addiction treatment systems may unknowingly adopt, reflect and mimic the symptoms of their clients. This parallel process, combined with the vicarious trauma encountered within the system, can lead to staff compassion fatigue, burnout
and unethical practices, all contributing to a breakdown in client care. Using the lens of Landy’s (1993, 1994, 2008, 2009) drama therapeutic Role Theory, along with Wegscheider-Cruse’s (1981) Family Roles, this article examines possibilities that exist for an embodied understanding
of vicarious trauma and parallel process found at the systems level, in an effort to offer direct care workers a better understanding of the implicit and disembodied roles they play.