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Sample records for affects cluster root

  1. Root uptake and phytotoxicity of nanosized molybdenum octahedral clusters

    International Nuclear Information System (INIS)

    Highlights: ► We investigated the effect of nanosized Mo6 clusters on the growth of rapeseed plants. ► The aggregation state of the clusters depends on the dispersion medium. ► The concentration-dependant toxicity of the clusters depends on aggregation state. ► We took into account the possible contribution to toxicity of dissolved ionic species. ► The root uptake of the clusters was followed by NanoSIMS. - Abstract: Here are examined the root uptake and phytotoxicity of octahedral hexamolybdenum clusters on rapeseed plants using the solid state compound Cs2Mo6Br14 as cluster precursor. [Mo6Br14]2− cluster units are nanosized entities offering a strong and stable emission in the near-infrared region with numerous applications in biotechnology. To investigate cluster toxicity on rapeseed plants, two different culture systems have been set up, using either a water-sorbing suspension of cluster aggregates or an ethanol-sorbing solution of dispersed nanosized clusters. Size, shape, surface area and state of clusters in both medium were analyzed by FE-SEM, BET and XPS. The potential contribution of cluster dissolution to phytotoxicity was evaluated by ICP-OES and toxicity analysis of Mo, Br and Cs. We showed that the clusters did not affect seed germination but greatly inhibited plant growth. This inhibition was much more important when plants were treated with nanosized entities than with microsized cluster aggregates. In addition, nanosized clusters affected the root morphology in a different manner than microsized cluster aggregates, as shown by FE-SEM observations. The root penetration of the clusters was followed by secondary ion mass spectroscopy with high spatial resolution (NanoSIMS) and was also found to be much more important for treatments with nanosized clusters.

  2. How the spatial variation of tree roots affects slope stability

    Science.gov (United States)

    Mao, Zhun; Stokes, A.; Jourdan, C.; Rey, H.; Courbaud, B.; Saint-André, L.

    2010-05-01

    It is now widely recognized that plant roots can reinforce soil against shallow mass movement. Although studies on the interactions between vegetation and slope stability have significantly augmented in recent years, a clear understanding of the spatial dynamics of root reinforcement (through additional cohesion by roots) in subalpine forest is still limited, especially with regard to the roles of different forest management strategies or ecological landscapes. The architecture of root systems is important for soil cohesion, but in reality it is not possible to measure the orientation of each root in a system. Therefore, knowledge on the effect of root orientation and anisotropy on root cohesion on the basis of in situ data is scanty. To determine the effect of root orientation in root cohesion models, we investigated root anisotropy in two mixed, mature, naturally regenerated, subalpine forests of Norway spruce (Picea abies), and Silver fir (Abies alba). Trees were clustered into islands, with open spaces between each group, resulting in strong mosaic heterogeneity within the forest stand. Trenches within and between clusters of trees were dug and root distribution was measured in three dimensions. We then simulated the influence of different values for a root anisotropy correction factor in forests with different ecological structures and soil depths. Using these data, we have carried out simulations of slope stability by calculating the slope factor of safety depending on stand structure. Results should enable us to better estimate the risk of shallow slope failure depending on the type of forest and species.

  3. A conformal mapping approach to a root-clustering problem

    International Nuclear Information System (INIS)

    This paper presents a new approach for matrix root-clustering in sophisticated and multiply-connected regions of the complex plane. The parametric sweeping method and a concept of the closed forbidden region covered by a set of modified three-parametrical Cassini regions are used. A conformal mapping approach was applied to formulate the main results of the paper. An application of the developed method to the problem of matrix root-clustering in a multiply connected region is shown for illustration

  4. Effect of parameter choice in root water uptake models – the arrangement of root hydraulic properties within the root architecture affects dynamics and efficiency of root water uptake

    OpenAIRE

    Bechmann, M.; Schneider, C; Carminati, A.; Vetterlein, D.; Attinger, S.; Hildebrandt, A

    2014-01-01

    Detailed three-dimensional models of root water uptake have become increasingly popular for investigating the process of root water uptake. However, they suffer from a lack of information on important parameters, particularly on the spatial distribution of root axial and radial conductivities, which vary greatly along a root system. In this paper we explore how the arrangement of those root hydraulic properties and branching within the root system affects modelled uptake dynamics, xylem water...

  5. Secondary chronic cluster headache due to trigeminal nerve root compression.

    Science.gov (United States)

    Mjåset, Christer; Russell, M B; Russell, M Bjørn

    2010-12-01

    A 50-year-old woman had a gradual onset of chronic headache located in the right temporal region and a burning sensation in the root of the tongue which over a year evolved into chronic cluster headache with a milder chronic headache in-between the severe cluster headache attacks. A cerebral magnetic resonance imaging (MRI) showed vascular compression of the trigeminal nerve root on the pain side. Neurosurgery microvascular decompression relieved the patient's chronic cluster headache, the chronic intermittent headache and the burning tongue sensation. The effect was persistent at a 1 year follow-up. Patients with atypical symptoms of cluster headache should be examined with cerebral MRI angiography of arteries and veins to exclude symptomatic causes. PMID:20384588

  6. Plant Hormones: How They Affect Root Formation.

    Science.gov (United States)

    Reinhard, Diana Hereda

    This science study aid, produced by the U.S. Department of Agriculture, includes a series of plant rooting activities for secondary science classes. The material in the pamphlet is written for students and includes background information on plant hormones, a vocabulary list, and five learning activities. Objectives, needed materials, and…

  7. Beneficial Microbes Affect Endogenous Mechanisms Controlling Root Development.

    Science.gov (United States)

    Verbon, Eline H; Liberman, Louisa M

    2016-03-01

    Plants have incredible developmental plasticity, enabling them to respond to a wide range of environmental conditions. Among these conditions is the presence of plant growth-promoting rhizobacteria (PGPR) in the soil. Recent studies show that PGPR affect Arabidopsis thaliana root growth and development by modulating cell division and differentiation in the primary root and influencing lateral root development. These effects lead to dramatic changes in root system architecture that significantly impact aboveground plant growth. Thus, PGPR may promote shoot growth via their effect on root developmental programs. This review focuses on contextualizing root developmental changes elicited by PGPR in light of our understanding of plant-microbe interactions and root developmental biology. PMID:26875056

  8. The affective discourse dynamics of metaphor clustering The affective discourse dynamics of metaphor clustering

    Directory of Open Access Journals (Sweden)

    Lynne Cameron

    2010-05-01

    Full Text Available

    Metaphor is examined in the very different iscourse contexts of the classroom and of reconciliation talk to highlight the neglected affective dimension. The distribution of metaphors across discourse shows clustering at certain points, often where speakers are engaged in critical interpersonal discourse activity. Clusters in classroom talk co-occur with sequences of agenda management where teachers prepare students for upcoming lessons and with giving feedback to students, both of which require careful management of interpersonal and affective issues. Clusters in reconciliation talk co-occur with discourse management and with two situations with significant affective dynamics: appropriation of metaphor and exploration of alternative scenarios.

    Metaphor is examined in the very different iscourse contexts of the classroom and of reconciliation talk to highlight the neglected affective dimension. The distribution of metaphors across discourse shows clustering at certain points, often where speakers are engaged in critical interpersonal discourse activity. Clusters in classroom talk co-occur with sequences of agenda management where teachers prepare students for upcoming lessons and with giving feedback to students, both of which require careful management of interpersonal and affective issues. Clusters in reconciliation talk co-occur with discourse management and with two situations with significant affective dynamics: appropriation of metaphor and exploration of alternative scenarios.

  9. Root-Zone Glyphosate Exposure Adversely Affects Two Ditch Species

    Directory of Open Access Journals (Sweden)

    Lyndsay E. Saunders

    2013-12-01

    Full Text Available Glyphosate, one of the most applied herbicides globally, has been extensively studied for its effects on non-target organisms. In the field, following precipitation, glyphosate runs off into agricultural ditches where it infiltrates into the soil and thus may encounter the roots of vegetation. These edge-of-field ditches share many characteristics with wetlands, including the ability to reduce loads of anthropogenic chemicals through uptake, transformation, and retention. Different species within the ditches may have a differential sensitivity to exposure of the root zone to glyphosate, contributing to patterns of abundance of ruderal species. The present laboratory experiment investigated whether two species commonly found in agricultural ditches in southcentral United States were affected by root zone glyphosate in a dose-dependent manner, with the objective of identifying a sublethal concentration threshold. The root zone of individuals of Polygonum hydropiperoides and Panicum hemitomon were exposed to four concentrations of glyphosate. Leaf chlorophyll content was measured, and the ratio of aboveground biomass to belowground biomass and survival were quantified. The findings from this study showed that root zone glyphosate exposure negatively affected both species including dose-dependent reductions in chlorophyll content. P. hydropiperdoides showed the greatest negative response, with decreased belowground biomass allocation and total mortality at the highest concentrations tested.

  10. Root-zone glyphosate exposure adversely affects two ditch species.

    Science.gov (United States)

    Saunders, Lyndsay E; Koontz, Melissa B; Pezeshki, Reza

    2013-01-01

    Glyphosate, one of the most applied herbicides globally, has been extensively studied for its effects on non-target organisms. In the field, following precipitation, glyphosate runs off into agricultural ditches where it infiltrates into the soil and thus may encounter the roots of vegetation. These edge-of-field ditches share many characteristics with wetlands, including the ability to reduce loads of anthropogenic chemicals through uptake, transformation, and retention. Different species within the ditches may have a differential sensitivity to exposure of the root zone to glyphosate, contributing to patterns of abundance of ruderal species. The present laboratory experiment investigated whether two species commonly found in agricultural ditches in southcentral United States were affected by root zone glyphosate in a dose-dependent manner, with the objective of identifying a sublethal concentration threshold. The root zone of individuals of Polygonum hydropiperoides and Panicum hemitomon were exposed to four concentrations of glyphosate. Leaf chlorophyll content was measured, and the ratio of aboveground biomass to belowground biomass and survival were quantified. The findings from this study showed that root zone glyphosate exposure negatively affected both species including dose-dependent reductions in chlorophyll content. P. hydropiperdoides showed the greatest negative response, with decreased belowground biomass allocation and total mortality at the highest concentrations tested. PMID:24833234

  11. Dynamic parallel ROOT facility clusters on the Alice Environment

    International Nuclear Information System (INIS)

    The ALICE collaboration has developed a production environment (AliEn) that implements the full set of the Grid tools enabling the full offline computational work-flow of the experiment, simulation, reconstruction and data analysis, in a distributed and heterogeneous computing environment. In addition to the analysis on the Grid, ALICE uses a set of local interactive analysis facilities installed with the Parallel ROOT Facility (PROOF). PROOF enables physicists to analyze medium-sized (order of 200-300 TB) data sets on a short time scale. The default installation of PROOF is on a static dedicated cluster, typically 200-300 cores. This well-proven approach, has its limitations, more specifically for analysis of larger datasets or when the installation of a dedicated cluster is not possible. Using a new framework called PoD (Proof on Demand), PROOF can be used directly on Grid-enabled clusters, by dynamically assigning interactive nodes on user request. The integration of Proof on Demand in the AliEn framework provides private dynamic PROOF clusters as a Grid service. This functionality is transparent to the user who will submit interactive jobs to the AliEn system.

  12. Robust root clustering for linear uncertain systems using generalized Lyapunov theory

    Science.gov (United States)

    Yedavalli, R. K.

    1993-01-01

    Consideration is given to the problem of matrix root clustering in subregions of a complex plane for linear state space models with real parameter uncertainty. The nominal matrix root clustering theory of Gutman & Jury (1981) using the generalized Liapunov equation is extended to the perturbed matrix case, and bounds are derived on the perturbation to maintain root clustering inside a given region. The theory makes it possible to obtain an explicit relationship between the parameters of the root clustering region and the uncertainty range of the parameter space.

  13. How Dark Energy Affects the MOND Theory in Clusters

    OpenAIRE

    Man Ho Chan

    2012-01-01

    Modified Newtonian Dynamics (MOND) is one of the successful theories to explain the dark matter problem in galaxies. However, the data from clusters and the cosmic microwave background (CMB) indicate some dark matter should exist in larger scales. In addition, recent dynamical studies of clusters show that the effect of dark energy should not be ignored in cluster scale. In this article, I will demonstrate how dark energy affects the cluster mass calculation by using MOND. Also, I will show t...

  14. How Clustering Affects Epidemics in Random Networks

    CERN Document Server

    Coupechoux, Emilie

    2012-01-01

    Motivated by the analysis of social networks, we study a model of random networks that has both a given degree distribution and a tunable clustering coefficient. We consider two types of growth processes on these graphs: diffusion and symmetric threshold model. The diffusion process is inspired from epidemic models. It is characterized by an infection probability, each neighbor transmitting the epidemic independently. In the symmetric threshold process, the interactions are still local but the propagation rule is governed by a threshold (that might vary among the different nodes). An interesting example of symmetric threshold process is the contagion process, which is inspired by a simple coordination game played on the network. Both types of processes have been used to model spread of new ideas, technologies, viruses or worms and results have been obtained for random graphs with no clustering. In this paper, we are able to analyze the impact of clustering on the growth processes. While clustering inhibits th...

  15. Sulfur nutrient availability regulates root elongation by affecting root indole-3-acetic acid levels and the stem cell niche

    Institute of Scientific and Technical Information of China (English)

    Qing Zhao; Yu Wu; Lei Gao; Jun Ma; Chuan-You Li; Cheng-Bin Xiang

    2014-01-01

    Sulfur is an essential macronutrient for plants with numerous biological functions. However, the influence of sulfur nutrient availability on the regulation of root development remains largely unknown. Here, we report the response of Arabidopsis thaliana L. root development and growth to different levels of sulfate, demonstrating that low sulfate levels promote the primary root elongation. By using various reporter lines, we examined in vivo IAA level and distribution, cel division, and root meristem in response to different sulfate levels. Meanwhile the dynamic changes of in vivo cysteine, glutathione, and IAA levels were measured. Root cysteine, glutathione, and IAA levels are positively correlated with external sulfate levels in the physiological range, which eventual y affect root system architecture. Low sulfate levels also downregulate the genes involved in auxin biosynthesis and transport, and elevate the accumulation of PLT1 and PLT2. This study suggests that sulfate level affects the primary root elongation by regulating the endogenous auxin level and root stem cel niche maintenance.

  16. How clustering dark energy affects matter perturbations

    Science.gov (United States)

    Mehrabi, A.; Basilakos, S.; Pace, F.

    2015-09-01

    The rate of structure formation in the Universe is different in homogeneous and clustered dark energy models. The degree of dark energy clustering depends on the magnitude of its effective sound speed c2_eff and for c2_eff=0 dark energy clusters in a similar fashion to dark matter while for c2_eff=1 it stays (approximately) homogeneous. In this paper we consider two distinct equations of state for the dark energy component, wd = const and w_d=w_0+w_1(z/1+z) with c2_eff as a free parameter and we try to constrain the dark energy effective sound speed using current available data including Type Ia supernovae, baryon acoustic oscillation, cosmic microwave background shift parameter (Planck and WMAP), Hubble parameter, big bang nucleosynthesis and the growth rate of structures fσ8(z). At first we derive the most general form of the equations governing dark matter and dark energy clustering under the assumption that c2_eff=const. Finally, performing an overall likelihood analysis we find that the likelihood function peaks at c2_eff=0; however, the dark energy sound speed is degenerate with respect to the cosmological parameters, namely Ωm and wd.

  17. How Dark Energy Affects the MOND Theory in Clusters

    Directory of Open Access Journals (Sweden)

    Man Ho Chan

    2012-09-01

    Full Text Available Modified Newtonian Dynamics (MOND is one of the successful theories to explain the dark matter problem in galaxies. However, the data from clusters and the cosmic microwave background (CMB indicate some dark matter should exist in larger scales. In addition, recent dynamical studies of clusters show that the effect of dark energy should not be ignored in cluster scale. In this article, I will demonstrate how dark energy affects the cluster mass calculation by using MOND. Also, I will show that the calculated cluster mass is consistent with the total matter to baryonic matter ratio obtained by the CMB data.

  18. Aircraft ride quality controller design using new robust root clustering theory for linear uncertain systems

    Science.gov (United States)

    Yedavalli, R. K.

    1992-01-01

    The aspect of controller design for improving the ride quality of aircraft in terms of damping ratio and natural frequency specifications on the short period dynamics is addressed. The controller is designed to be robust with respect to uncertainties in the real parameters of the control design model such as uncertainties in the dimensional stability derivatives, imperfections in actuator/sensor locations and possibly variations in flight conditions, etc. The design is based on a new robust root clustering theory developed by the author by extending the nominal root clustering theory of Gutman and Jury to perturbed matrices. The proposed methodology allows to get an explicit relationship between the parameters of the root clustering region and the uncertainty radius of the parameter space. The current literature available for robust stability becomes a special case of this unified theory. The bounds derived on the parameter perturbation for robust root clustering are then used in selecting the robust controller.

  19. A mathematical model for investigating the effect of cluster roots on plant nutrient uptake

    KAUST Repository

    Zygalakis, K. C.

    2012-04-01

    Cluster roots are thought to play an important role in mediating nutrient uptake by plants. In this paper we develop a mathematical model for the transport and uptake of phosphate by a single root. Phosphate is assumed to diffuse in the soil fluid phase and can also solubilised due to citrate exudation. Using multiple scale homogenisation techniques we derive an effective model that accounts for the cumulative effect of citrate exudation and phosphate uptake by cluster roots whilst still retaining all the necessary information about the microscale geometry and effects. © 2012 EDP Sciences and Springer.

  20. Factors affecting root curvature of mandibular first molar

    International Nuclear Information System (INIS)

    To find the cause of root curvature by use of panoramic and lateral cephalometric radiograph. Twenty six 1st graders whose mandibular 1st molars just emerged into the mouth were selected. Panoramic and lateral cephalometric radiograph were taken at grade 1 and 6, longitudinally. In cephalometric radio graph, mandibular plane angle, ramus-occlusal place angle, gonial angle, and gonion-gnathion distance(Go-Gn distance) were measured. In panoramic radiograph, elongated root length and root angle were measured by means of digital subtraction radiography. Occlusal plane-tooth axis angle was measured, too. Pearson correlations were used to evaluate the relationships between root curvature and elongated length and longitudinal variations of all variables. Multiple regression equation using related variables was computed. The pearson correlation coefficient between curved angle and longitudinal variations of occlusal plane-tooth axis angle and ramus-occlusal plane angle was 0.350 and 0.401, respectively (p1+0.745X2(Y: root angle, X1: variation of occlusal plane-tooth axis angle, X2: variation of ramus-occlusal plane angle). It was suspected that the reasons of root curvature were change of tooth axis caused by contact with 2nd deciduous tooth and amount of mesial and superior movement related to change of occlusal plane

  1. Factors affecting root curvature of mandibular first molar

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Hang Moon [Kangnung National University, Kangnung (Korea, Republic of); Yi, Won Jin; Heo, Min Suk; Kim, Jung Hwa; Choi, Soon Chul; Park, Tae Won [Seoul National Univ., Seoul (Korea, Republic of)

    2006-03-15

    To find the cause of root curvature by use of panoramic and lateral cephalometric radiograph. Twenty six 1st graders whose mandibular 1st molars just emerged into the mouth were selected. Panoramic and lateral cephalometric radiograph were taken at grade 1 and 6, longitudinally. In cephalometric radio graph, mandibular plane angle, ramus-occlusal place angle, gonial angle, and gonion-gnathion distance(Go-Gn distance) were measured. In panoramic radiograph, elongated root length and root angle were measured by means of digital subtraction radiography. Occlusal plane-tooth axis angle was measured, too. Pearson correlations were used to evaluate the relationships between root curvature and elongated length and longitudinal variations of all variables. Multiple regression equation using related variables was computed. The pearson correlation coefficient between curved angle and longitudinal variations of occlusal plane-tooth axis angle and ramus-occlusal plane angle was 0.350 and 0.401, respectively (p<0.05). There was no significant correlation between elongated root length and longitudinal variations of all variables. The resulting regression equation was Y=10.209+0.208X{sub 1}+0.745X{sub 2}(Y: root angle, X{sub 1}: variation of occlusal plane-tooth axis angle, X{sub 2}: variation of ramus-occlusal plane angle). It was suspected that the reasons of root curvature were change of tooth axis caused by contact with 2nd deciduous tooth and amount of mesial and superior movement related to change of occlusal plane.

  2. Root activity, some crops as affected by soil strength

    International Nuclear Information System (INIS)

    To find out the relationship between soil strength and root activity of different crops, the experiment was conducted on Haryana Agricultural University Farm, Hissar. Open drums were placed one foot deep. 5 cm thick densities 1.4 (Control), 1.6 and 1.8 g/cc were placed at 25 cm depth in various drums. Test crops taken were pea, gram, wheat and barley. Bulk density of higher order in combination with low moisture levels resulted in more detrimental effects on root penetration of the crop in general but at some stages significant interaction between bulk density and moisture was observed where low moisture favoured the root entry through the compacted layers of soil. (author)

  3. Evaluation of sugar beet genotypes for root traits by principal component analysis and cluster analysis

    Directory of Open Access Journals (Sweden)

    Danojević Dario

    2016-01-01

    Full Text Available Sugar beet is the most important crop for sugar production in Europe. Wide genetic variability is essential in sugar beet breeding programs. The aim of this study is to evaluate variability for the main root traits and differences between monogerm and multigerm sugar beet genotypes from the breeding collection at the Institute of Field and Vegetable Crops. The following traits were analyzed: root weight (g, dry matter content (%, root head weight (g, root/head ratio (%, number of cambial rings, root length (cm and root diameter (cm. Mean values for two years per genotype were standardized and used for analysis. Principal Component Analysis (PCA and Cluster Analysis (CA were used to examine the level of diversity for 20 genotypes and to rank the contributions of the variables. According to CA genotypes could be placed into five main groups, where a large number of multigerm genotypes were put in one group. On average multigerm genotypes were characterized by higher mean values for root weight, length, diameter and lower root head ratio. Multigerm genotypes had higher coefficients of variation for nearly all measured root traits. [Projekat Ministarstva nauke Republike Srbije, br. TR31015

  4. Fire affects root decomposition, soil food web structure, and carbon flow in tallgrass prairie

    OpenAIRE

    Shaw, E. Ashley; Denef, Karolien; Milano de Tomasel, Cecilia; Cotrufo, M. Francesca; Wall, Diana H

    2016-01-01

    Root litter decomposition is a major component of carbon (C) cycling in grasslands, where it provides energy and nutrients for soil microbes and fauna. This is especially important in grasslands where fire is common and removes aboveground litter accumulation. In this study, we investigated whether fire affects root decomposition and C flow through the belowground food web. In a greenhouse experiment, we applied 13C-enriched big bluestem (Andropogon gerardii) root litter to ...

  5. Mycorrhizal fungi affect root stele tissue in grasses.

    Energy Technology Data Exchange (ETDEWEB)

    Miller, R. M.; Hetrick, B. A. D.; Wilson, G. W. T.; Environmental Research; Northern Iowa Univ.; Kansas State Univ.

    1997-01-01

    Although arbuscular mycorrhizal symbiosis was initially believed to have little or no impact on root morphology, we now recognize that subtle changes do occur and that these changes may be of considerable consequence to host growth and nutrition, as well as functional growth strategy. In examining the stele and root diameters of C3 and C4 grasses, C4 grasses were demonstrated to have a significantly larger proportion of their fibrous roots occupied by stele tissue than do C3 grasses. In fact, functional growth strategy (C3 versus C4) was observed to be a relatively good predictor of stele area. Mycorrhizal fungi also influenced the amount of stele tissue, but the effect was not the same for both C3 and C4 grasses. The stele area of all C4 grasses except for Sorghastrum nutans was greater in the presence of mycorrhizal colonization. Among the C3 grasses, only Bromus inermis showed a significant increase, although Elymus cinereus and Lolium perenne displayed significant decreases in response to arbuscular mycorrhizal colonization. Changes in the stele area of the plant species were closely related to their responsiveness to mycorrhizal symbiosis and might in part explain both beneficial and detrimental responses of plants to mycorrhizae. An increase in stele circumference induced by mycorrhizae would allow for greater uptake and passage of water and nutrients to the vascular cylinder, and growth depressions could be a direct outcome of reduced stele circumference. Thus, differences in stele circumference represent a possible mechanism for mycorrhizal impacts on host plants. These findings indicate that structural differences among grasses are related to different functional capabilities and further emphasize the need for better integration of comparative anatomy and morphology procedures in the study of mycorrhizal symbiosis.

  6. Root cooling strongly affects diel leaf growth dynamics, water and carbohydrate relations in Ricinus communis.

    Science.gov (United States)

    Poiré, Richard; Schneider, Heike; Thorpe, Michael R; Kuhn, Arnd J; Schurr, Ulrich; Walter, Achim

    2010-03-01

    In laboratory and greenhouse experiments with potted plants, shoots and roots are exposed to temperature regimes throughout a 24 h (diel) cycle that can differ strongly from the regime under which these plants have evolved. In the field, roots are often exposed to lower temperatures than shoots. When the root-zone temperature in Ricinus communis was decreased below a threshold value, leaf growth occurred preferentially at night and was strongly inhibited during the day. Overall, leaf expansion, shoot biomass growth, root elongation and ramification decreased rapidly, carbon fluxes from shoot to root were diminished and carbohydrate contents of both root and shoot increased. Further, transpiration rate was not affected, yet hydrostatic tensions in shoot xylem increased. When root temperature was increased again, xylem tension reduced, leaf growth recovered rapidly, carbon fluxes from shoot to root increased, and carbohydrate pools were depleted. We hypothesize that the decreased uptake of water in cool roots diminishes the growth potential of the entire plant - especially diurnally, when the growing leaf loses water via transpiration. As a consequence, leaf growth and metabolite concentrations can vary enormously, depending on root-zone temperature and its heterogeneity inside pots. PMID:19968824

  7. Physical mechanisms of plant roots affecting weathering and leaching of loess soil

    Institute of Scientific and Technical Information of China (English)

    LI; Yong; ZHANG; Qingwen; WAN; Guojiang; HUANG; Ronggui; PIAO; Hechun; BAI; Lingyu; LI; Lu

    2006-01-01

    Plant roots have potential impacts on soil mineral weathering and leaching. Our objective is to understand the physical mechanisms of plant roots affecting weathering and leaching of loess soil. Root densities were measured through the method of a large-size dug profile, and transport fluxes of soil elements were determined using an undisturbed monolith soil infiltration device on the hilly and gully regions of the Chinese Loess Plateau. The results show that the improvement effects of soil environment by plant roots are mainly controlled by the density and weight of the fibrous roots with the diameters less than 1 mm. Plant roots have the stronger effects on soil physical properties than chemical properties. The principal components analysis (PCA) indicates that soil physical properties by plant roots account for 56.7% of variations in soil environment whereas soil chemical properties and pH contribute about 24.2% of the soil variations. The roles of plant roots in controlling soil weathering and leaching increased in the following order: infiltration enhancement > increase of bioactive substance > stabilization of soil structure. The effects of plant roots on soil mineral weathering and leaching can be quantified using the multiple regression models with the high prediction accuracies developed in this study.

  8. Genes of the most conserved WOX clade in plants affect root and flower development in Arabidopsis

    Directory of Open Access Journals (Sweden)

    Moreau Hervé

    2008-10-01

    Full Text Available Abstract Background The Wuschel related homeobox (WOX family proteins are key regulators implicated in the determination of cell fate in plants by preventing cell differentiation. A recent WOX phylogeny, based on WOX homeodomains, showed that all of the Physcomitrella patens and Selaginella moellendorffii WOX proteins clustered into a single orthologous group. We hypothesized that members of this group might preferentially share a significant part of their function in phylogenetically distant organisms. Hence, we first validated the limits of the WOX13 orthologous group (WOX13 OG using the occurrence of other clade specific signatures and conserved intron insertion sites. Secondly, a functional analysis using expression data and mutants was undertaken. Results The WOX13 OG contained the most conserved plant WOX proteins including the only WOX detected in the highly proliferating basal unicellular and photosynthetic organism Ostreococcus tauri. A large expansion of the WOX family was observed after the separation of mosses from other land plants and before monocots and dicots have arisen. In Arabidopsis thaliana, AtWOX13 was dynamically expressed during primary and lateral root initiation and development, in gynoecium and during embryo development. AtWOX13 appeared to affect the floral transition. An intriguing clade, represented by the functional AtWOX14 gene inside the WOX13 OG, was only found in the Brassicaceae. Compared to AtWOX13, the gene expression profile of AtWOX14 was restricted to the early stages of lateral root formation and specific to developing anthers. A mutational insertion upstream of the AtWOX14 homeodomain sequence led to abnormal root development, a delay in the floral transition and premature anther differentiation. Conclusion Our data provide evidence in favor of the WOX13 OG as the clade containing the most conserved WOX genes and established a functional link to organ initiation and development in Arabidopsis, most

  9. Burning management in the tallgrass prairie affects root decomposition, soil food web structure and carbon flow

    Science.gov (United States)

    Shaw, E. A.; Denef, K.; Milano de Tomasel, C.; Cotrufo, M. F.; Wall, D. H.

    2015-09-01

    Root litter decomposition is a major component of carbon (C) cycling in grasslands, where it provides energy and nutrients for soil microbes and fauna. This is especially important in grasslands where fire is a common management practice and removes aboveground litter accumulation. In this study, we investigated whether fire affects root decomposition and C flow through the belowground food web. In a greenhouse experiment, we applied 13C-enriched big bluestem (Andropogon gerardii) root litter to intact tallgrass prairie soil cores collected from annually burned (AB) and infrequently burned (IB) treatments at the Konza Prairie Long Term Ecological Research (LTER) site. Incorporation of 13C into microbial phospholipid fatty acids and nematode trophic groups was measured on six occasions during a 180-day decomposition study to determine how C was translocated through the soil food web. Results showed significantly different soil communities between treatments and higher microbial abundance for IB. Root decomposition occurred rapidly and was significantly greater for AB. Microbes and their nematode consumers immediately assimilated root litter C in both treatments. Root litter C was preferentially incorporated in a few groups of microbes and nematodes, but depended on burn treatment: fungi, Gram-negative bacteria, Gram-positive bacteria, and fungivore nematodes for AB and only omnivore nematodes for IB. The overall microbial pool of root litter-derived C significantly increased over time but was not significantly different between burn treatments. The nematode pool of root litter-derived C also significantly increased over time, and was significantly higher for the AB treatment at 35 and 90 days after litter addition. In conclusion, the C flow from root litter to microbes to nematodes is not only measurable, but significant, indicating that higher nematode trophic levels are critical components of C flow during root decomposition which, in turn, is significantly

  10. Fire affects root decomposition, soil food web structure, and carbon flow in tallgrass prairie

    Science.gov (United States)

    Shaw, E. Ashley; Denef, Karolien; Milano de Tomasel, Cecilia; Cotrufo, M. Francesca; Wall, Diana H.

    2016-05-01

    Root litter decomposition is a major component of carbon (C) cycling in grasslands, where it provides energy and nutrients for soil microbes and fauna. This is especially important in grasslands where fire is common and removes aboveground litter accumulation. In this study, we investigated whether fire affects root decomposition and C flow through the belowground food web. In a greenhouse experiment, we applied 13C-enriched big bluestem (Andropogon gerardii) root litter to intact tallgrass prairie soil cores collected from annually burned (AB) and infrequently burned (IB) treatments at the Konza Prairie Long Term Ecological Research (LTER) site. Incorporation of 13C into microbial phospholipid fatty acids and nematode trophic groups was measured on six occasions during a 180-day decomposition study to determine how C was translocated through the soil food web. Results showed significantly different soil communities between treatments and higher microbial abundance for IB. Root decomposition occurred rapidly and was significantly greater for AB. Microbes and their nematode consumers immediately assimilated root litter C in both treatments. Root litter C was preferentially incorporated in a few groups of microbes and nematodes, but depended on burn treatment: fungi, Gram-negative bacteria, Gram-positive bacteria, and fungivore nematodes for AB and only omnivore nematodes for IB. The overall microbial pool of root-litter-derived C significantly increased over time but was not significantly different between burn treatments. The nematode pool of root-litter-derived C also significantly increased over time, and was significantly higher for the AB treatment at 35 and 90 days after litter addition. In conclusion, the C flow from root litter to microbes to nematodes is not only measurable but also significant, indicating that higher nematode trophic levels are critical components of C flow during root decomposition, which, in turn, is significantly affected by fire. Not

  11. Vitamin D3 affects growth and Ca2+ uptake by Phaseolus vulgaris roots cultured in vitro

    International Nuclear Information System (INIS)

    Vitamin D3 at low concentration (10−9 M) inhibited the growth of Phaseolus vulgaris L. (cv. Contrancha) roots in vitro as measured by elongation (14 h) and [3H]-leucine incorporation into protein (2 h), and increased their labelling with 45Ca2+ (2 h). Cycloheximide and puromycin (50 u.M) blocked vitamin D3 stimulation of root 45Ca2+ labelling, indicating that it is mediated by de novo protein synthesis. The calcium ionophore X-537A (10−5JW) induced similar changes both in root elongation and 45Ca2+ uptake (14 h). This may indicate that the inhibitory effects of the sterol on root growth are mediated by changes in Ca2+ fluxes. However, this interpretation should be further strengthened by additional studies as the ionophore may have acted on root growth, affecting physiological processes other than Ca2+ transport. (author)

  12. The Root Herbivore History of the Soil Affects the Productivity of a Grassland Plant Community and Determines Plant Response to New Root Herbivore Attack

    OpenAIRE

    Sonnemann, Ilja; Hempel, Stefan; Beutel, Maria; Hanauer, Nicola; Reidinger, Stefan; Wurst, Susanne

    2013-01-01

    Insect root herbivores can alter plant community structure by affecting the competitive ability of single plants. However, their effects can be modified by the soil environment. Root herbivory itself may induce changes in the soil biota community, and it has recently been shown that these changes can affect plant growth in a subsequent season or plant generation. However, so far it is not known whether these root herbivore history effects (i) are detectable at the plant community level and/or...

  13. Does cluster-root activity benefit nutrient uptake and growth of co-existing species?

    Science.gov (United States)

    Muler, Ana L; Oliveira, Rafael S; Lambers, Hans; Veneklaas, Erik J

    2014-01-01

    Species that inhabit phosphorus- (P) and micronutrient-impoverished soils typically have adaptations to enhance the acquisition of these nutrients, for example cluster roots in Proteaceae. However, there are several species co-occurring in the same environment that do not produce similar specialised roots. This study aims to investigate whether one of these species (Scholtzia involucrata) can benefit from the mobilisation of P or micronutrients by the cluster roots of co-occurring Banksia attenuata, and also to examine the response of B. attenuata to the presence of S. involucrata. We conducted a greenhouse experiment, using a replacement series design, where B. attenuata and S. involucrata shared a pot at proportions of 2:0, 1:2 and 0:4. S. involucrata plants grew more in length, were heavier and had higher manganese (Mn) concentrations in their young leaves when grown next to one individual of B. attenuata and one individual of S. involucrata than when grown with three conspecifics. All S. involucrata individuals were colonised by arbuscular mycorrhizal fungi, and possibly Rhizoctonia. Additionally, P concentration was higher in the young leaves of B. attenuata when grown with another B. attenuata than when grown with two individuals of S. involucrata, despite the smaller size of the S. involucrata individuals. Our results demonstrate that intraspecific competition was stronger than interspecific competition for S. involucrata, but not for B. attenuata. We conclude that cluster roots of B. attenuata facilitate the acquisition of nutrients by neighbouring shrubs by making P and Mn more available for their neighbours. PMID:23934064

  14. NaCl salinity affects lateral root development in Plantago maritima

    NARCIS (Netherlands)

    Rubinigg, M; Wenisch, J; Elzenga, JTM; Stulen, [No Value

    2004-01-01

    Root growth and morphology were assessed weekly in hydroponically-grown seedlings of the halophyte Plantago maritima L. during exposure to 0, 50, 100 and 200 mM NaCl for 21 d. Relative growth rate was reduced by 25% at 200 mM NaCl. The lower NaCl treatments did not affect relative growth rates. Prim

  15. Glycerol affects root development through regulation of multiple pathways in Arabidopsis.

    Directory of Open Access Journals (Sweden)

    Jun Hu

    demonstrated that glycerol treatment altered endogenous levels of G3P, phosphate and ROS, affected auxin distribution and cell division in the root meristem, and eventually resulted in modifications of root development.

  16. Glycerol affects root development through regulation of multiple pathways in Arabidopsis.

    Science.gov (United States)

    Hu, Jun; Zhang, Yonghong; Wang, Jinfang; Zhou, Yongming

    2014-01-01

    treatment altered endogenous levels of G3P, phosphate and ROS, affected auxin distribution and cell division in the root meristem, and eventually resulted in modifications of root development. PMID:24465999

  17. How the Clustering of Phonological Neighbors Affects Visual Word Recognition

    Science.gov (United States)

    Yates, Mark

    2013-01-01

    In recent years, a new scientific field known as network science has been emerging. Network science is concerned with understanding the structure and properties of networks. One concept that is commonly used in describing a network is how the nodes in the network cluster together. The current research applied the idea of clustering to the study of…

  18. Sensory Clusters of Toddlers with Autism Spectrum Disorders: Differences in Affective Symptoms

    Science.gov (United States)

    Ben-Sasson, A.; Cermak, S. A.; Orsmond, G. I.; Tager-Flusberg, H.; Kadlec, M. B.; Carter, A. S.

    2008-01-01

    Background: Individuals with autism spectrum disorders (ASDs) show variability in their sensory behaviors. In this study we identified clusters of toddlers with ASDs who shared sensory profiles and examined differences in affective symptoms across these clusters. Method: Using cluster analysis 170 toddlers with ASDs were grouped based on parent…

  19. The presence of root-feeding nematodes - Not AMF - Affects an herbivore dispersal strategy

    Science.gov (United States)

    De Roissart, Annelies; Peña, Eduardo de la; Van Oyen, Lien; Van Leeuwen, Thomas; Ballhorn, Daniel J.; Bonte, Dries

    2013-10-01

    Plant quality and aboveground herbivore performance are influenced either directly or indirectly by the soil community. As herbivore dispersal is a conditional strategy relative to plant quality, we examined whether belowground biotic interactions (the presence of root-feeding nematodes or arbuscular mycorrhizal fungi) affect aerial dispersal of a phytophagous mite (Tetranychus urticae) through changes in performance of their host plant (Phaseolus vulgaris). Aerial dispersal strategies of mites were analyzed in wind-tunnel experiments, in which a unique mite pre-dispersal behavior (rearing) was assessed in relation to the presence of belowground biota on the host plant on which mites developed. Spider mite pre-dispersal behavior significantly increased with the experienced mite density on the host during development. Additionally, plants infected with root-feeding nematodes induced an increase of spider mite aerial dispersal behavior. The results highlight that belowground herbivores can affect population dynamics of aboveground herbivores by altering dispersal strategies.

  20. Sowing Density: A Neglected Factor Fundamentally Affecting Root Distribution and Biomass Allocation of Field Grown Spring Barley (Hordeum Vulgare L.

    Directory of Open Access Journals (Sweden)

    Vera L Hecht

    2016-06-01

    Full Text Available Studies after the function of root traits and the genetic variation in these traits are often conducted under controlled conditions using individual potted plants. Little is known about root growth under field conditions and how root traits are affected by agronomic practices in particular sowing density. We hypothesized that with increasing sowing density, root length density (root length per soil volume, cm cm-3 increases in the top soil as well as specific root length (root length per root dry weight, cm g-1 due to greater investment in fine roots. Therefore, we studied two spring barley cultivars at ten different sowing densities (24-340 seeds m-2 in two consecutive years in a clay loam field in Germany and established sowing density dose response curves for several root and shoot traits. We took soil cores for measuring roots up to a depth of 60 cm in and between plant rows (inter-row distance 21 cm. Root length density increased with increasing sowing density and was greatest in the plant row in the top soil (0-10 cm. Greater sowing density increased specific root length partly through greater production of fine roots in the top soil. Rooting depth of the major root axes (root diameter class 0.4-1.0 mm was not affected. Root mass fraction decreased, while stem mass fraction increased with sowing density and over time. Leaf mass fraction was constant over sowing density but greater leaf area was realized through increased specific leaf area. Considering fertilization, we assume that light competition caused plants to grow more shoot mass at the cost of investment into roots, which is partly compensated by increased SRL and increased shallow rooting. Increased biomass per area with greater densities suggest that density increases the efficiency of the cropping system, however, declines in harvest index at densities over 230 plants m-2 suggest that this efficiency did not translate into greater yield. We conclude that plant density is a

  1. Root exudation and root development of lettuce (Lactuca sativa L.cv. Tizian as affected by different soils

    Directory of Open Access Journals (Sweden)

    GünterNeumann

    2014-01-01

    Full Text Available Development and activity of plant roots exhibits high adaptive variability. Although it is well-documented, that physicochemical soil properties can strongly influence root morphology and root exudation, particularly under field conditions, a comparative assessment is complicated by the impact of additional factors, such as climate and cropping history. To overcome these limitations, in this study, field soils originating from an unique experimental plot system with three different soil types, which were stored at the same field site for ten years and exposed to the same agricultural management practice, were used for an investigation on effects of soil type on root development and root exudation. Lettuce (Lactuca sativa L. cv. Tizian was used as a model plant, grown under controlled environmental conditions in a minirhizotrone system equipped with root observation windows (rhizoboxes. Root exudates were collected by placing sorption filters onto the root surface followed by subsequent extraction and GC-MS profiling of the trapped compounds. Surprisingly, even in absence of external stress factors with known impact on root exudation, such as pH extremes, water and nutrient limitations/toxicities or soil structure effects (use of sieved soils, root growth characteristics (root length, fine root development as well as profiles of root exudates were strongly influenced by the soil type used for plant cultivation. The results coincided well with differences in rhizosphere bacterial communities, detected in field-grown lettuce plants cultivated on the same soils (Schreiter et al., this issue. The findings suggest that the observed differences may be the result of plant interactions with the soil-specific microbiomes.

  2. Increasing shrub abundance and N addition in Arctic tundra affect leaf and root litter decomposition differently

    Science.gov (United States)

    McLaren, J.; van de Weg, M. J.; Shaver, G. R.; Gough, L.

    2013-12-01

    Changes in global climate have resulted in a ';greening' of the Arctic as the abundance of deciduous shrub species increases. Consequently, not only the living plant community, but also the litter composition changes, which in turn can affect carbon turnover patterns in the Arctic. We examined effects of changing litter composition (both root and leaf litter) on decomposition rates with a litter bag study, and specifically focused on the impact of deciduous shrub Betula nana litter on litter decomposition from two evergreen shrubs (Ledum palustre, and Vaccinium vitis-idaea) and one graminoid (Eriophorum vaginatum) species. Additionally, we investigated how decomposition was affected by nutrient availability by placing the litterbags in an ambient and a fertilized moist acidic tundra environment. Measurements were carried out seasonally over 2 years (after snow melt, mid-growing season, end growing season). We measured litter mass loss over time, as well as the respiration rates (standardized for temperature and moisture) and temperature sensitivity of litter respiration at the time of harvesting the litter bags. For leaves, Betula litter decomposed faster than the other three species, with Eriophorum leaves decomposing the slowest. This pattern was observed for both mass loss and litter respiration rates, although the differences in respiration became smaller over time. Surprisingly, combining Betula with any other species resulted in slower overall weight loss rates than would be predicted based on monoculture weight loss rates. This contrasted with litter respiration at the time of sampling, which showed a positive mixing effect of adding Betula leaf liter to the other species. Apparently, during the first winter months (September - May) Betula litter decomposition is negatively affected by mixing the species and this legacy can still be observed in the total mass loss results later in the year. For root litter there were fewer effects of species identity on root

  3. Osmotic stress at the barley root affects expression of circadian clock genes in the shoot.

    Science.gov (United States)

    Habte, Ermias; Müller, Lukas M; Shtaya, Munqez; Davis, Seth J; von Korff, Maria

    2014-06-01

    The circadian clock is an important timing system that controls physiological responses to abiotic stresses in plants. However, there is little information on the effects of the clock on stress adaptation in important crops, like barley. In addition, we do not know how osmotic stress perceived at the roots affect the shoot circadian clock. Barley genotypes, carrying natural variation at the photoperiod response and clock genes Ppd-H1 and HvELF3, were grown under control and osmotic stress conditions to record changes in the diurnal expression of clock and stress-response genes and in physiological traits. Variation at HvELF3 affected the expression phase and shape of clock and stress-response genes, while variation at Ppd-H1 only affected the expression levels of stress genes. Osmotic stress up-regulated expression of clock and stress-response genes and advanced their expression peaks. Clock genes controlled the expression of stress-response genes, but had minor effects on gas exchange and leaf transpiration. This study demonstrated that osmotic stress at the barley root altered clock gene expression in the shoot and acted as a spatial input signal into the clock. Unlike in Arabidopsis, barley primary assimilation was less controlled by the clock and more responsive to environmental perturbations, such as osmotic stress. PMID:24895755

  4. Elevated atmospheric CO2 levels affect community structure of rice root-associated bacteria

    OpenAIRE

    Okubo, Takashi; Liu, Dongyan; Tsurumaru, Hirohito; Ikeda, Seishi; Asakawa, Susumu; Tokida, Takeshi; Tago, Kanako; Hayatsu, Masahito; Aoki, Naohiro; Ishimaru, Ken; Ujiie, Kazuhiro; Usui, Yasuhiro; Nakamura, Hirofumi; Sakai, Hidemitsu; Hayashi, Kentaro

    2015-01-01

    A number of studies have shown that elevated atmospheric CO2 ([CO2]) affects rice yields and grain quality. However, the responses of root-associated bacteria to [CO2] elevation have not been characterized in a large-scale field study. We conducted a free-air CO2 enrichment (FACE) experiment (ambient + 200 μmol.mol−1) using three rice cultivars (Akita 63, Takanari, and Koshihikari) and two experimental lines of Koshihikari [chromosome segment substitution and near-isogenic lines (NILs)] to de...

  5. Elevated atmospheric CO2 levels affect community structure of rice root-associated bacteria

    OpenAIRE

    Kiwamu eMinamisawa; Takashi eOkubo; Dongyan eLiu; Hirohito eTsurumaru; Seishi eIkeda; Susumu eAsakawa; Takeshi eTokida; Kanako eTago; Masahito eHayatsu; Naohiro eAoki; Ken eIshimaru; Kazuhiro eUjiie; Yasuhiro eUsui; Hirofumi eNakamura; Hidemitsu eSakai

    2015-01-01

    A number of studies have shown that elevated atmospheric CO2 ([CO2]) affects rice yields and grain quality. However, the responses of root-associated bacteria to [CO2] elevation have not been characterized in a large-scale field study. We conducted a free-air CO2 enrichment (FACE) experiment (ambient + 200 μmol⋅mol−1) using three rice cultivars (Akita 63, Takanari, and Koshihikari) and two experimental lines of Koshihikari (chromosome segment substitution and near-isogenic lines) to determine...

  6. Root-zone acidity affects relative uptake of nitrate and ammonium from mixed nitrogen sources

    Science.gov (United States)

    Vessey, J. K.; Henry, L. T.; Chaillou, S.; Raper, C. D. Jr; Raper CD, J. r. (Principal Investigator)

    1990-01-01

    Soybean plants (Glycine max [L.] Merr. cv Ransom) were grown for 21 days on 4 sources of N (1.0 mM NO3-, 0.67 mM NO3- plus 0.33 mM NH4+, 0.33 mM NO3- plus 0.67 mM NH4+, and 1.0 mM NH4+) in hydroponic culture with the acidity of the nutrient solution controlled at pH 6.0, 5.5, 5.0, and 4.5. Dry matter and total N accumulation of the plants was not significantly affected by N-source at any of the pH levels except for decreases in these parameters in plants supplied solely with NH4+ at pH 4.5. Shoot-to-root ratios increased in plants which had an increased proportion [correction of proporiton] of NH4(+)-N in their nutrient solutions at all levels of root-zone pH. Uptake of NO3- and NH4+ was monitored daily by ion chromatography as depletion of these ions from the replenished hydroponic solutions. At all pH levels the proportion of either ion that was absorbed increased as the ratio of that ion increased in the nutrient solution. In plants which were supplied with sources of NO3- plus NH4+, NH4+ was absorbed at a ratio of 2:1 over NO3- at pH 6.0. As the pH of the root-zone declined, however, NH4+ uptake decreased and NO3- uptake increased. Thus, the NH4+ to NO3- uptake ratio declined with decreases in root-zone pH. The data indicate a negative effect of declining root-zone pH on NH4+ uptake and supports a hypothesis that the inhibition of growth of plants dependent on NH4(+)-N at low pH is due to a decline in NH4+ uptake and a consequential limitation of growth by N stress.

  7. Modulation of Root Signals in Relation to Stomatal Sensitivity to Root-sourced Abscisic Acid in Drought-affected Plants

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Stomatal sensitivity to root signals induced by soil drying may vary between environments and plant species. This is likely central role in root to shoot signaling. pH and hydraulic signals may interact with ABA signals and thus, jointly regulate stomatal responses to changed soil water status. pH itself can be modified by several factors, among which the chemical compositions In the xylem stream and the live cells surrounding the vessels play crucial roles. In addition to the xylem pH,more attention should be paid to the direct modulation of leaf apoplastic pH, because many chemical compositions might strongly modify the leaf apoplastlc pH while having no significant effect on the xylem pH. The direct modulation of the ABA signal intensity may be more important for the regulation of stomatal responses to soil drying than the ABA signal per se.The ABA signal is also regulated by the ABA catabolism and the supply of precursors to the roots If a sustained root to shoot communication of soil drying operates at the whole plant level. More importantly, ABA catabolism could play crucial roles In the determination of the fate of the ABA signal and thereby control the stomatal behavior of the root-sourced ABA signal.

  8. Analyzing the factors affecting network lifetime cluster-based wireless sensor network

    International Nuclear Information System (INIS)

    Cluster-based wireless sensor networks enable the efficient utilization of the limited energy resources of the deployed sensor nodes and hence prolong the node as well as network lifetime. Low Energy Adaptive Clustering Hierarchy (Leach) is one of the most promising clustering protocol proposed for wireless sensor networks. This paper provides the energy utilization and lifetime analysis for cluster-based wireless sensor networks based upon LEACH protocol. Simulation results identify some important factors that induce unbalanced energy utilization between the sensor nodes and hence affect the network lifetime in these types of networks. These results highlight the need for a standardized, adaptive and distributed clustering technique that can increase the network lifetime by further balancing the energy utilization among sensor nodes. (author)

  9. Nano titania aided clustering and adhesion of beneficial bacteria to plant roots to enhance crop growth and stress management

    Science.gov (United States)

    Palmqvist, N. G. M.; Bejai, S.; Meijer, J.; Seisenbaeva, G. A.; Kessler, V. G.

    2015-05-01

    A novel use of Titania nanoparticles as agents in the nano interface interaction between a beneficial plant growth promoting bacterium (Bacillus amyloliquefaciens UCMB5113) and oilseed rape plants (Brassica napus) for protection against the fungal pathogen Alternaria brassicae is presented. Two different TiO2 nanoparticle material were produced by the Sol-Gel approach, one using the patented Captigel method and the other one applying TiBALDH precursor. The particles were characterized by transmission electron microscopy, thermogravimetric analysis, X-ray diffraction, dynamic light scattering and nano particle tracking analysis. Scanning electron microscopy showed that the bacterium was living in clusters on the roots and the combined energy-dispersive X-ray spectroscopy analysis revealed that titanium was present in these cluster formations. Confocal laser scanning microscopy further demonstrated an increased bacterial colonization of Arabidopsis thaliana roots and a semi-quantitative microscopic assay confirmed an increased bacterial adhesion to the roots. An increased amount of adhered bacteria was further confirmed by quantitative fluorescence measurements. The degree of infection by the fungus was measured and quantified by real-time-qPCR. Results showed that Titania nanoparticles increased adhesion of beneficial bacteria on to the roots of oilseed rape and protected the plants against infection.

  10. Cysteine 295 indirectly affects Ni coordination of carbon monoxide dehydrogenase-II C-cluster

    International Nuclear Information System (INIS)

    Highlights: •CODH-II harbors a unique [Ni-Fe-S] cluster. •We substituted the ligand residues of Cys295 and His261. •Dramatic decreases in Ni content upon substitutions were observed. •All substitutions did not affect Fe-S clusters assembly. •CO oxidation activity was decreased by the substitutions. -- Abstract: A unique [Ni–Fe–S] cluster (C-cluster) constitutes the active center of Ni-containing carbon monoxide dehydrogenases (CODHs). His261, which coordinates one of the Fe atoms with Cys295, is suggested to be the only residue required for Ni coordination in the C-cluster. To evaluate the role of Cys295, we constructed CODH-II variants. Ala substitution for the Cys295 substitution resulted in the decrease of Ni content and didn’t result in major change of Fe content. In addition, the substitution had no effect on the ability to assemble a full complement of [Fe–S] clusters. This strongly suggests Cys295 indirectly and His261 together affect Ni-coordination in the C-cluster

  11. The Garlic Allelochemical Diallyl Disulfide Affects Tomato Root Growth by Influencing Cell Division, Phytohormone Balance and Expansin Gene Expression

    Science.gov (United States)

    Cheng, Fang; Cheng, Zhihui; Meng, Huanwen; Tang, Xiangwei

    2016-01-01

    Diallyl disulfide (DADS) is a volatile organosulfur compound derived from garlic (Allium sativum L.), and it is known as an allelochemical responsible for the strong allelopathic potential of garlic. The anticancer properties of DADS have been studied in experimental animals and various types of cancer cells, but to date, little is known about its mode of action as an allelochemical at the cytological level. The current research presents further studies on the effects of DADS on tomato (Solanum lycopersicum L.) seed germination, root growth, mitotic index, and cell size in root meristem, as well as the phytohormone levels and expression profile of auxin biosynthesis genes (FZYs), auxin transport genes (SlPINs), and expansin genes (EXPs) in tomato root. The results showed a biphasic, dose-dependent effect on tomato seed germination and root growth under different DADS concentrations. Lower concentrations (0.01–0.62 mM) of DADS significantly promoted root growth, whereas higher levels (6.20–20.67 mM) showed inhibitory effects. Cytological observations showed that the cell length of root meristem was increased and that the mitotic activity of meristematic cells in seedling root tips was enhanced at lower concentrations of DADS. In contrast, DADS at higher concentrations inhibited root growth by affecting both the length and division activity of meristematic cells. However, the cell width of the root meristem was not affected. Additionally, DADS increased the IAA and ZR contents of seedling roots in a dose-dependent manner. The influence on IAA content may be mediated by the up-regulation of FZYs and PINs. Further investigation into the underlying mechanism revealed that the expression levels of tomato EXPs were significantly affected by DADS. The expression levels of EXPB2 and beta-expansin precursor were increased after 3 d, and those of EXP1, EXPB3 and EXLB1 were increased after 5 d of DADS treatment (0.41 mM). This result suggests that tomato root growth may be

  12. The Garlic Allelochemical Diallyl Disulfide Affects Tomato Root Growth by Influencing Cell Division, Phytohormone Balance and Expansin Gene Expression.

    Science.gov (United States)

    Cheng, Fang; Cheng, Zhihui; Meng, Huanwen; Tang, Xiangwei

    2016-01-01

    Diallyl disulfide (DADS) is a volatile organosulfur compound derived from garlic (Allium sativum L.), and it is known as an allelochemical responsible for the strong allelopathic potential of garlic. The anticancer properties of DADS have been studied in experimental animals and various types of cancer cells, but to date, little is known about its mode of action as an allelochemical at the cytological level. The current research presents further studies on the effects of DADS on tomato (Solanum lycopersicum L.) seed germination, root growth, mitotic index, and cell size in root meristem, as well as the phytohormone levels and expression profile of auxin biosynthesis genes (FZYs), auxin transport genes (SlPINs), and expansin genes (EXPs) in tomato root. The results showed a biphasic, dose-dependent effect on tomato seed germination and root growth under different DADS concentrations. Lower concentrations (0.01-0.62 mM) of DADS significantly promoted root growth, whereas higher levels (6.20-20.67 mM) showed inhibitory effects. Cytological observations showed that the cell length of root meristem was increased and that the mitotic activity of meristematic cells in seedling root tips was enhanced at lower concentrations of DADS. In contrast, DADS at higher concentrations inhibited root growth by affecting both the length and division activity of meristematic cells. However, the cell width of the root meristem was not affected. Additionally, DADS increased the IAA and ZR contents of seedling roots in a dose-dependent manner. The influence on IAA content may be mediated by the up-regulation of FZYs and PINs. Further investigation into the underlying mechanism revealed that the expression levels of tomato EXPs were significantly affected by DADS. The expression levels of EXPB2 and beta-expansin precursor were increased after 3 d, and those of EXP1, EXPB3 and EXLB1 were increased after 5 d of DADS treatment (0.41 mM). This result suggests that tomato root growth may be

  13. Evaluation of sugar beet genotypes for root traits by principal component analysis and cluster analysis

    OpenAIRE

    Danojević Dario; Ćurčić Živko; Nagl Nevena; Taški-Ajduković Ksenija; Boćanski Jan

    2016-01-01

    Sugar beet is the most important crop for sugar production in Europe. Wide genetic variability is essential in sugar beet breeding programs. The aim of this study is to evaluate variability for the main root traits and differences between monogerm and multigerm sugar beet genotypes from the breeding collection at the Institute of Field and Vegetable Crops. The following traits were analyzed: root weight (g), dry matter content (%), root head weight (g), roo...

  14. Factors affecting morphogenetic potential in oilseed rape roots of the Skrzeszowicki and Start cultivars

    Directory of Open Access Journals (Sweden)

    Janina Rogozińska

    2014-02-01

    Full Text Available The effect of the origin of root segments, seedling age, growth substances and gelled or liquid media were tested in respect to the morphogenetic potential of rape root segments of Skrzeszowicki (high glucosinolate content and Start (low glucosinolate content cultivars. Callus and roots were formed on all root segments after an approximately 2 week growth period; buds were formed after ca. 4 weeks only on segments adjacent to the hypocotyl. Higher concentrations of auxin and cytokinins were required for bud induction. Cultivar differences in the morphogenetic responses of the root segments were found. They were manifested by the more abundant callus formation (BAP+NAA and more numerous lateral roots and buds (KIN+IBA on segments from the Skrzeszowicki cultivar than from the Start cultivar.

  15. Glycerol Affects Root Development through Regulation of Multiple Pathways in Arabidopsis

    OpenAIRE

    Jun Hu; Yonghong Zhang; Jinfang Wang; Yongming Zhou

    2014-01-01

    Glycerol metabolism has been well studied biochemically. However, the means by which glycerol functions in plant development is not well understood. This study aimed to investigate the mechanism underlying the effects of glycerol on root development in Arabidopsis thaliana. Exogenous glycerol inhibited primary root growth and altered lateral root development in wild-type plants. These phenotypes appeared concurrently with increased endogenous glycerol-3-phosphate (G3P) and H2O2 contents in se...

  16. Too Little, Too Late: How the Tidal Evolution of Hot Jupiters affects Transit Surveys of Clusters

    CERN Document Server

    Debes, John H

    2010-01-01

    The tidal evolution of hot Jupiters may change the efficiency of transit surveys of stellar clusters. The orbital decay that hot Jupiters suffer may result in their destruction, leaving fewer transiting planets in older clusters. We calculate the impact tidal evolution has for different assumed stellar populations, including that of 47~Tuc, a globular cluster that was the focus of an intense HST search for transits. We find that in older clusters one expects to detect fewer transiting planets by a factor of two for surveys sensitive to Jupiter-like planets in orbits out to 0.5~AU, and up to a factor of 25 for surveys sensitive to Jupiter-like planets in orbits out to 0.08~AU. Additionally, tidal evolution affects the distribution of transiting planets as a function of semi-major axis, producing larger orbital period gaps for transiting planets as the age of the cluster increases. Tidal evolution can explain the lack of detected exoplanets in 47~Tuc without invoking other mechanisms. Four open clusters residin...

  17. Root rot diseases of sugarbeet (Beta vulgaris L as affected by defloliation intensity

    Directory of Open Access Journals (Sweden)

    Karadimos Dimitros A.

    2006-01-01

    Full Text Available The aim of this work was to study the effect of sugar beet re-growth after water stress defoliation on root rots of three cultivars (Europa, Rival Corsica, which were spring sown in Thessaly, central Greece, for two growing seasons (2003-04. At the beginning of July, sugar beets were subjected to water deficit with irrigation withholding. A month later, three defoliation levels (control - C, moderate - MD, severe - SD and irrigation were applied. Thus, sugar beets were forced to re-grow and three harvests (15, 30 and 40 days after defoliation - DAD were conducted. Rotted roots per hectare were counted and pathogens were identified. Data were analyzed as a four-factor randomized complete block design with years, defoliation levels, sampling times and cultivars as main factors. The number of rotted roots was increased with the defoliation level and was significantly higher for SD sugar beets (3748 roots ha–1. No significant differences were found between C and MD treatments (1543 and 2116 roots ha–1, respectively. Rival was the most susceptible cultivar to root rots. Sugar beets were more susceptible to rotting 15 and 40 DAD (2778 and 2998 roots ha–1. The causal agents of root rots were the fungi, Fusarium spp., Rhizopus stolonifer, Macrophomina phaseolina and Rhizoctonia solani.

  18. Does species richness affect fine root biomass and production in young forest plantations?

    DEFF Research Database (Denmark)

    Domisch, Timo; Finér, Leena; Dawud, Seid Muhie; Vesterdal, Lars; Raulund-Rasmussen, Karsten

    2015-01-01

    Tree species diversity has been reported to increase forest ecosystem above-ground biomass and productivity, but little is known about below-ground biomass and production in diverse mixed forests compared to single-species forests. For testing whether species richness increases below-ground biomass...... and production and thus complementarity between forest tree species in young stands, we determined fine root biomass and production of trees and ground vegetation in two experimental plantations representing gradients in tree species richness. Additionally, we measured tree fine root length and...... determined species composition from fine root biomass samples with the near-infrared reflectance spectroscopy method. We did not observe higher biomass or production in mixed stands compared to monocultures. Neither did we observe any differences in tree root length or fine root turnover. One reason for this...

  19. Affective Dispositions and PTSD Symptom Clusters in Female Interpersonal Trauma Survivors.

    Science.gov (United States)

    Brown, Wilson J; Bruce, Steven E; Buchholz, Katherine R; Artime, Tiffany M; Hu, Emily; Sheline, Yvette I

    2016-02-01

    Interpersonal trauma (IPT) against women can have dire psychological consequences including persistent maladaptive changes in the subjective experience of affect. Contemporary literature has firmly established heightened negative affect (NA) as a risk and maintenance factor for posttraumatic stress disorder (PTSD). However, the relationship between NA and PTSD symptoms is not well understood within IPT survivors, the majority of whom are female, as much of this research has focused on combat veterans. In addition, the connection between positive affect (PA) and PTSD symptoms has yet to be examined. With increased emphasis on "negative alterations in cognitions and mood . . ." as an independent symptom cluster of PTSD in the Diagnostic and Statistical Manual of Mental Disorders (5th ed.; DSM-5), understanding the relationship between self-reported affectivity and the classic PTSD symptom clusters may be increasingly useful in differentiating symptom presentations of trauma-related psychopathology. The current study directly compared self-reported trait NA and PA with total severity and frequency cluster scores from the Clinician-Administered PTSD Scale (CAPS) in 54 female survivors of IPT who met criteria for PTSD. Results identify NA (but not PA) as a consistent predictor of total PTSD symptoms and, specifically, re-experiencing symptoms. PMID:25389192

  20. Root growth conditions in the topsoil as affected by tillage intensity

    DEFF Research Database (Denmark)

    Kadziene, Grazina; Munkholm, Lars Juhl; Mutegi, James

    2011-01-01

    treatments were direct drilling (D), harrowing 8–10 cm (H), and ploughing (P) to 20 cm depth. A chisel coulter drill was used in the H and D treatments and a traditional seed drill in the P treatment. Undisturbed soil cores were collected in November 2008 at soil field moisture capacity from the 4–8 and 12......Many studies have reported impeded root growth in topsoil under reduced tillage or direct drilling, but few have quantified the effects on the least limiting water range for root growth. This study explored the effects of tillage intensity on critical soil physical conditions for root growth in the...

  1. Live substrate positively affects root growth and stolon direction in the woodland strawberry, Fragaria vesca

    OpenAIRE

    Waters, Erica M.; Watson, Maxine A.

    2015-01-01

    Studies of clonal plant foraging generally focus on growth responses to patch quality once rooted. Here we explore the possibility of true plant foraging; the ability to detect and respond to patch resource status prior to rooting. Two greenhouse experiments were conducted to investigate the morphological changes that occur when individual daughter ramets of Fragaria vesca (woodland strawberry) were exposed to air above live (non-sterilized) or dead (sterilized) substrates. Contact between da...

  2. Methyl jasmonate affects morphology, number and activity of endoplasmic reticulum bodies in Raphanus sativus root cells.

    Science.gov (United States)

    Gotté, Maxime; Ghosh, Rajgourab; Bernard, Sophie; Nguema-Ona, Eric; Vicré-Gibouin, Maïté; Hara-Nishimura, Ikuko; Driouich, Azeddine

    2015-01-01

    The endoplasmic reticulum (ER) bodies are ER-derived structures that are found in Brassicaceae species and thought to play a role in defense. Here, we have investigated the occurrence, distribution and function of ER bodies in root cells of Raphanus sativus using a combination of microscopic and biochemical methods. We have also assessed the response of ER bodies to methyl jasmonate (MeJA), a phytohormone that mediates plant defense against wounding and pathogens. Our results show that (i) ER bodies do occur in different root cell types from the root cap region to the differentiation zone; (ii) they do accumulate a PYK10-like protein similar to the major marker protein of ER bodies that is involved in defense in Arabidopsis thaliana; and (iii) treatment of root cells with MeJA causes a significant increase in the number of ER bodies and the activity of β-glucosidases. More importantly, MeJA was found to induce the formation of very long ER bodies that results from the fusion of small ones, a phenomenon that has not been reported in any other study so far. These findings demonstrate that MeJA impacts the number and morphology of functional ER bodies and stimulates ER body enzyme activities, probably to participate in defense responses of radish root. They also suggest that these structures may provide a defensive system specific to root cells. PMID:25305245

  3. Transport of root-derived CO2 via the transpiration stream affects aboveground tree physiology

    Science.gov (United States)

    Bloemen, J.; McGuire, M. A.; Aubrey, D. P.; Teskey, R. O.; Steppe, K.

    2012-04-01

    Recent research on soil CO2 efflux has shown that belowground autotrophic respiration is largely underestimated using classical net CO2 flux measurements. Aubrey & Teskey (2009) found that in forest ecosystems a substantial portion of the CO2 released from root respiration remained within the root system and was transported aboveground in the stem via the transpiration stream. The magnitude of this upward movement of CO2 from belowground tissues suggested important implications for how we measure above- and belowground respiration. If a considerable fraction of root-respired CO2 is transported aboveground, where it might be fixed in woody and leaf tissues, then we are routinely underestimating the amount of C needed to sustain belowground tissues. In this study, we infused 13C labeled water into the base of field-grown poplar trees as a surrogate for root-respired CO2 to investigate the possible role of root-derived CO2 as substrate for carbon fixation. The label was transported upwards from the base of the tree toward the top. During its ascent, the 13C label was removed from the transpiration stream and fixed by chlorophyll-containing woody (young bark and xylem) and leaf (petiole) tissues. Moreover, based on 13C analysis of gas samples, we observed that up to 88 ± 0.10 % of the label applied was lost to the atmosphere by stem and branch efflux higher in the trees. Given that one-half of root-respired CO2 may follow this internal flux pathway (Aubrey & Teskey, 2009), we calculated that up to 44% of the root-respired CO2 could diffuse to the atmosphere once transported to the stem and branches. Thus, a large portion of CO2 that diffuses out of aboveground tissues may actually result from root respiration. Our results show that CO2 originating belowground can be transported internally to aboveground parts of trees, where it will have an important impact on tree physiology. Internal transport of CO2 indicates that the gas exchange approach to estimating above- and

  4. Rooting, growth, and color mutation of poinsettias affected by gamma radiation

    International Nuclear Information System (INIS)

    This experiment was carried out to investigate the effects of gamma-radiation on the rooting, growth, and color mutation in poinsettia. Using 10 poinsettia varieties ('Lollipop', 'Little Peace', 'Happy Day', 'Early Bird', 'Pixy Red', 'Happy Time', 'Heidi', 'Red Bell', 'Clara', and 'Scarlet') bred by National Institute of Horticultural and Herbal Science, 100 Gy of gamma ray was irradiated at the stage of callused cuttings. Four weeks after sticking cuttings in the rooting media, 8 cultivars showed 100% of root formation, but 'Early Bird' rooted 24.4% and even died off during the cutting propagation. After planting rooted cuttings, survival rate until flowering time varied among irradiated cultivars. While 'Pixy Red' and 'Heidi' survived about 98%, 'Clara', 'Happy Day', and 'Early Bird' survived lesser than 30%. All irradiated plants showed remarkably shorter plant height, lesser branch numbers than non-irradiated control plants. Thirty color mutants were obtained among 281 plants survived until flowering time. Nine were complete color mutated branches, whereas 21 mutants were partially color mutated bracts and transitional leaves. Color patterns mutated by 100 Gy of gamma ray were divided into pink, hot pink, light red and spotted (pink spots with red main color). Pink mutants were commonly obtained. Complete color mutants were discovered from 4 plants of 'Pixy Red', 2 plants of 'Red Bell' and 3 plants of Lollipop

  5. Live substrate positively affects root growth and stolon direction in the woodland strawberry, Fragaria vesca.

    Science.gov (United States)

    Waters, Erica M; Watson, Maxine A

    2015-01-01

    Studies of clonal plant foraging generally focus on growth responses to patch quality once rooted. Here we explore the possibility of true plant foraging; the ability to detect and respond to patch resource status prior to rooting. Two greenhouse experiments were conducted to investigate the morphological changes that occur when individual daughter ramets of Fragaria vesca (woodland strawberry) were exposed to air above live (non-sterilized) or dead (sterilized) substrates. Contact between daughter ramets and substrate was prohibited. Daughter ramet root biomass was significantly larger over live versus dead substrate. Root:shoot ratio also increased over live substrate, a morphological response we interpret as indicative of active nutrient foraging. Daughter ramet root biomass was positively correlated with mother ramet size over live but not dead substrate. Given the choice between a live versus a dead substrate, primary stolons extended preferentially toward live substrates. We conclude that exposure to live substrate drives positive nutrient foraging responses in F. vesca. We propose that volatiles emitted from the substrates might be effecting the morphological changes that occur during true nutrient foraging. PMID:26483826

  6. Live substrate positively affects root growth and stolon direction in the woodland strawberry, Fragaria vesca

    Directory of Open Access Journals (Sweden)

    Erica Marie Waters

    2015-09-01

    Full Text Available Studies of clonal plant foraging generally focus on growth responses to patch quality once rooted. Here we explore the possibility of true plant foraging; the ability to detect and respond to patch resource status prior to rooting. Two greenhouse experiments were conducted to investigate the morphological changes that occur when individual daughter ramets of Fragaria vesca (woodland strawberry were exposed to air above live (non-sterilized or dead (sterilized substrates. Contact between daughter ramets and substrate was prohibited. Daughter ramet root biomass was significantly larger over live versus dead substrate. Root:shoot ratio also increased over live substrate, a morphological response we interpret as indicative of active nutrient foraging. Daughter ramet root biomass was positively correlated with mother ramet size over live but not dead substrate. Given the choice between a live versus a dead substrate, primary stolons extended preferentially toward live substrates. We conclude that exposure to live substrate drives positive nutrient foraging responses in Fragaria vesca. We propose that volatiles emitted from by the substrates might be effecting the morphological changes that occur during true nutrient foraging.

  7. Cluster size and substrate temperature affecting thin film formation during copper cluster deposition on a Si (001) surface

    Institute of Scientific and Technical Information of China (English)

    Gong Heng-Feng; Lü Wei; Wang Lu-Min; Li Gong-Ping

    2012-01-01

    The soft deposition of Cu clusters on a Si (001) surface was studied by molecular dynamics simulations.The embedded atom method,the Stillinger-Weber and the Lennar Jones potentials were used to describe the interactions between the cluster atoms,between the substrate atoms,and between the cluster and the substrate atoms,respectively.The Cu13,Cu55,and Cu147 clusters were investigated at different substrate temperatures.We found that the substrate temperature had a significant effect on the Cu147 cluster.For smaller Cu13 and Cu55 clusters,the substrate temperature in the range of study appeared to have little effect on the mean center-of-mass height.The clusters showed better degrees of epitaxy at 800 K.With the same substrate temperature,the Cu55 cluster demonstrated the highest degree of epitaxy,followed by Cu147 and then Cu13 clusters.In addition,the Cu55 cluster showed the lowest mean center-of-mass height.These results suggested that the Cu55 cluster is a better choice for the thin-film formation among the clusters considered.Our studies may provide insight into the formation of desired Cu thin films on a Si substrate.

  8. Nitrate reductase and acid phosphatase activities as affected by inorganic phosphate in corn roots

    OpenAIRE

    Marie Kummerova; Józef Buczek

    2014-01-01

    The deficieny of inorganic phosphate in nutrient solution reduces by about 50 per cent NO3- absorption in corn seedlings, it decreases both in vitro and in vivo nitrate reductase (NR) activity, as well the potential and actual NR level and has a very weak effect on NR induction. Acid phosphatases activities increase in corn roots when the plants are grown in nutrient solution without phosphorus. We suggest that inorganic phosphate is required mainly for maintenance of NR activity rather, than...

  9. Suramin affects capsaicin responses and capsaicin-noxious heat interactions in rat dorsal root ganglia neurones

    Czech Academy of Sciences Publication Activity Database

    Vlachová, Viktorie; Lyfenko, Alla; Vyklický st., Ladislav; Orkand, R. K.

    2002-01-01

    Roč. 51, č. 2 (2002), s. 193-198. ISSN 0862-8408 R&D Projects: GA ČR GA305/00/1639; GA MŠk LN00B122 Institutional research plan: CEZ:AV0Z5011922 Keywords : dorsal root ganglia neurones * vanilloid receptor * capsaicin -noxious heat Subject RIV: ED - Physiology Impact factor: 0.984, year: 2002

  10. Movement of carbon to roots of food legumes as affected by soil moisture and fertilizer potassium

    International Nuclear Information System (INIS)

    Food legumes are an important component of agricultural systems in developing countries. They are cultivated in a wide range of environments where soil moisture could be generally considered limiting for optimum growth and yield. In terms of vegetative growth, root systems of plants adapt to extract the limited moisture from dry soils. Although it is known that fertilizer K helps plants mitigate soil moisture stress, this has not been evaluated on a comparative basis in food legumes. Therefore, a study was carried out under controlled conditions to determine the role of K+ in the movement of labelled C in three tropical food legumes that have differing optimal soil-moisture requirements. Common bean (Phaseolus vulgaris), mung bean (Vigna radiata), and cowpea (Vigna unguiculata) were grown under two moisture regimes with three levels of K+ (01, 1.0 and 3.0 mM K). Uniform seedlings of the three species were transplanted into pots containing quartz sand, maintained at two soil-moisture levels (High, less than 25% depleted of available soil moisture; Low, more than 50% depleted), by weighing at 3-day intervals and adding the required water or nutrient solution. The modified nutrient solutions had 0.1, 1.0 or 3.0 mM K+ with 1.5 mM N. The plants were kept in a growth chamber, maintained at 25 deg. /18 deg. C day/night, with a 16-h photoperiod, and at 60% humidity. At the V4 growth stage of each species, four plants were selected randomly, and approximately 1 cm2 of the upper surface of the youngest fully expanded leaf abraded with Carborundum. Thereafter, 5 μL of 14C contained in a 5-mM solution of sucrose (148 KBq) was applied to the abraded area. Another 10 μL of unlabelled sucrose was applied to the same area 10 min later and the plants replaced. After 24 h, they were carefully removed, roots washed, dried and weighed. Thereafter, the samples were ground and digested, and labelled C determined by liquid scintillation. Cowpea, the species most adapted to soil

  11. Nitrogen Addition as a Result of Long-Term Root Removal Affects Soil Organic Matter Dynamics

    Science.gov (United States)

    Crow, S. E.; Lajtha, K.

    2004-12-01

    A long-term field litter manipulation site was established in a mature coniferous forest stand at the H.J. Andrews Experimental Forest, OR, USA in 1997 in order to address how detrital inputs influence soil organic matter formation and accumulation. Soils at this site are Andisols and are characterized by high carbon (C) and low nitrogen (N) contents, due largely to the legacy of woody debris and extremely low atmospheric N deposition. Detrital treatments include trenching to remove roots, doubling wood and needle litter, and removing aboveground litter. In order to determine whether five years of detrital manipulation had altered organic matter quantity and lability at this site, soil from the top 0-5 cm of the A horizon was density fractionated to separate the labile light fraction (LF) from the more recalcitrant mineral soil in the heavy fraction (HF). Both density fractions and whole soils were incubated for one year in chambers designed such that repeated measurements of soil respiration and leachate chemistry could be made. Trenching resulted in the removal of labile root inputs from root exudates and turnover of fine roots and active mycorrhizal communities as well as an increase of available N by removing plant uptake. Since 1999, soil solution chemistry from tension lysimeters has shown greater total N and dissolved organic nitrogen (DON) flux and less dissolved organic carbon (DOC) flux to stream flow in the trenched plots relative to the other detrital treatments. C/N ratio and C content of both light and heavy fractions from the trenched plots were greater than other detrital treatments. In the lab incubation, over the course of a year C mineralization from these soils was suppressed. Cumulative DOC losses and CO2 efflux both were significantly less in soils from trenched plots than in other detrital treatments including controls. After day 150 of the incubation, leachates from the HF of plots with trenched treatments had a DOC/DON ratio significantly

  12. The Magea gene cluster regulates male germ cell apoptosis without affecting the fertility in mice

    Science.gov (United States)

    Hou, Siyuan; Xian, Li; Shi, Peiliang; Li, Chaojun; Lin, Zhaoyu; Gao, Xiang

    2016-01-01

    While apoptosis is essential for male germ cell development, improper activation of apoptosis in the testis can affect spermatogenesis and cause reproduction defects. Members of the MAGE-A (melanoma antigen family A) gene family are frequently clustered in mammalian genomes and are exclusively expressed in the testes of normal animals but abnormally activated in a wide variety of cancers. We investigated the potential roles of these genes in spermatogenesis by generating a mouse model with a 210-kb genomic deletion encompassing six members of the Magea gene cluster (Magea1, Magea2, Magea3, Magea5, Magea6 and Magea8). Male mice carrying the deletion displayed smaller testes from 2 months old with a marked increase in apoptotic germ cells in the first wave of spermatogenesis. Furthermore, we found that Magea genes prevented stress-induced spermatogenic apoptosis after N-ethyl-N-nitrosourea (ENU) treatment during the adult stage. Mechanistically, deletion of the Magea gene cluster resulted in a dramatic increase in apoptotic germ cells, predominantly spermatocytes, with activation of p53 and induction of Bax in the testes. These observations demonstrate that the Magea genes are crucial in maintaining normal testicular size and protecting germ cells from excessive apoptosis under genotoxic stress. PMID:27226137

  13. Interannual variation in root production in grassland affected by artficially modified amount of rainfall

    Czech Academy of Sciences Publication Activity Database

    Fiala, Karel; Tůma, Ivan; Holub, Petr

    2012-01-01

    Roč. 2012, č. 805298 (2012). ISSN 1537-744X R&D Projects: GA ČR GAP504/10/1486; GA ČR(CZ) GA526/06/0556; GA MŠk(CZ) ED1.1.00/02.0073 Institutional research plan: CEZ:AV0Z60050516; CEZ:AV0Z60870520 Institutional support: RVO:67985939 ; RVO:67179843 Keywords : root increment * below-ground plant mass * precipitation Subject RIV: EF - Botanics; EH - Ecology, Behaviour (UEK-B) Impact factor: 1.730, year: 2012

  14. Genes of the most conserved WOX clade in plants affect root and flower development in Arabidopsis

    OpenAIRE

    Moreau Hervé; Laufs Patrick; Morin Halima; Thareau Vincent; Claisse Gaelle; Toffano-Nioche Claire; Deveaux Yves; Kreis Martin; Lecharny Alain

    2008-01-01

    Abstract Background The Wuschel related homeobox (WOX) family proteins are key regulators implicated in the determination of cell fate in plants by preventing cell differentiation. A recent WOX phylogeny, based on WOX homeodomains, showed that all of the Physcomitrella patens and Selaginella moellendorffii WOX proteins clustered into a single orthologous group. We hypothesized that members of this group might preferentially share a significant part of their function in phylogenetically distan...

  15. Rooting of healthy and CVC-affected 'Valência' sweet orange stem cuttings, through the use of plant regulators

    Directory of Open Access Journals (Sweden)

    Gustavo Habermann

    2006-01-01

    Full Text Available Citrus variegated chlorosis (CVC is a disease caused by Xylella fastidiosa. Using different concentrations of plant regulators, such as auxins (indole-3-butyric acid and gibberellic acid biosynthesis-inhibitor (paclobutrazol, physiological rooting capacity of healthy and CVC-affected stem cuttings were evaluated in order to investigate the importance of plant hormone imbalance and xylem occlusion in plants with CVC. The percentages of dead, alive and rooted cuttings, cuttings with callus and mean number of roots per cuttings did not show statistical differences in response to the distinct concentrations of synthetic plant regulators. There were differences only between healthy and CVC-affected cuttings. This showed the importance of xylem occlusion and diffusive disturbances in diseased plants, in relation to root initiation capacity and hormonal translocation in the plant tissue.Clorose variegada dos citros (CVC é uma doença causada por Xylella fastidiosa, podendo determinar oclusão do xilema e desbalanço hormonal, o que por fim está relacionado ao processo de iniciação radicial em estacas. Usando diferentes concentrações de fitorreguladores, como auxinas (ácido 3-indol butírico e inibidores da biossíntese de ácido giberélico (paclobutrazol, que são promotores do enraizamento de estacas, verificou-se a capacidade fisiológica de enraizamento de estacas sadias e com CVC, a fim de investigar a importância do desbalanço hormonal e oclusão do xilema em plantas doentes. As porcentagens de estacas mortas, vivas, enraizadas e com calo e o número médio de raízes por estaca não mostraram diferenças estatísticas em resposta às diferentes concentrações dos reguladores vegetais sintéticos. Houve diferenças apenas entre estacas sadias e doentes. Isto aponta a importância da oclusão do xilema e distúrbios difusivos em plantas doentes, em relação à capacidade de iniciação radicial e à translocação hormonal no tecido

  16. "God of Small Things": Service Interaction's Roots in Regulatory Focus and Affectivity

    Directory of Open Access Journals (Sweden)

    Tali Seger-Guttmann

    2014-06-01

    Full Text Available We link regulatory focus, positive and negative affective states, and service behaviors to suggest that, salespersons' service interactions depend on their motivation (promotion- or prevention-focused and their emotional responses during the service encounter. Based on in-depth interviews with salespeople, a questionnaire applying the concepts of 'skeleton' (the core of exchange relations and 'tissue' (informal social behaviors was administered to 90 salespeople in apparel stores. Results supported our main assumption that salespeople interact with customers based on their regulatory focus (Promotion and Prevention and affectivity (PA and NA. Promotion focus was positively related to positive tissue behaviors (i.e., extra-role behaviors and to positive affect (PA and negatively related to negative affect (NA. Promotion-focused salespeople are more likely to demonstrate PA and high-quality service performance by adopting extra-role (tissue behaviors. PA and NA fully mediated the relationship between promotion focus and positive tissue behaviors I. Prevention focus was found to be positively correlated with skeleton behaviors (i.e., core behaviors and NA. No relationship was found between prevention focus and PA.

  17. Affect of uranium ore dust on separate indexes of nitrous exchange of rat liver using lacryc radices root extract

    International Nuclear Information System (INIS)

    Goal of the research - to reveal peculiarities of metabolic break of nitrous exchange of rat liver tissue at long-term inhalation affect of uranium dust in different terms, and to evaluate effectiveness of corrective effect of lacryc radices root extract. Experiments are executed on white not pedigree male rats with mass of 120-150g. Inhalation of uranium ore dust (UOD) is conducted with using of AID-1 apparatus of inhalation destroy. There are 3 (three) serial of researches are conducted. In blood serum and liver tissue we identified content of general albumen by unify method and activity of aminotransphcrase and gammaglutamiltranspeptidase (GGTP), using biochemical analyzer, content of urea is identified by enzymatic method, and albumen - by method of electrophoresis on paper. Corrective effect of water extract of lacryc radices root is examined. The abstract is devoted to one of the actual problem of modern radiobiology - study of system affects of low doses of ionized radiation on condition of nitrous exchange of rat liver tissue at long-term inhalation affect of uranium dust. In work we got new following results. For the first time by examination of dynamics of simple and complex albumen, separate indexes of nitrous exchange we studied system affect of low doses of ionized radiation, revealed dose-time differences of compensatory-adaptive and cytolysis response of liver tissue for long-term inhalation affects of an industrial dust of uranium ore in different doses. It is determined, that at inhalation of uranium dust in doses, equivalent to 5 maximum-allowed concentration (MAC), during 120 days process of albumen synthesis is activated in liver, that is confirmed by regular increase of albumen concentration in blood serum for 2 times to the end of observation in term of its fixed content in liver tissue. Pointed changes coincide with depression of processes of urea-formation almost in 2 times, consequent depression of aspartataminotraspherase (AsAT) and

  18. How nitrogen and sulphur addition, and a single drought event affect root phosphatase activity in Phalaris arundinacea.

    Science.gov (United States)

    Robroek, Bjorn J M; Adema, Erwin B; Venterink, Harry Olde; Leonardson, Lars; Wassen, Martin J

    2009-03-15

    Conservation and restoration of fens and fen meadows often aim to reduce soil nutrients, mainly nitrogen (N) and phosphorus (P). The biogeochemistry of P has received much attention as P-enrichment is expected to negatively impact on species diversity in wetlands. It is known that N, sulphur (S) and hydrological conditions affect the biogeochemistry of P, yet their interactive effects on P-dynamics are largely unknown. Additionally, in Europe, climate change has been predicted to lead to increases in summer drought. We performed a greenhouse experiment to elucidate the interactive effects of N, S and a single drought event on the P-availability for Phalaris arundinacea. Additionally, the response of plant phosphatase activity to these factors was measured over the two year experimental period. In contrast to results from earlier experiments, our treatments hardly affected soil P-availability. This may be explained by the higher pH in our soils, hampering the formation of Fe-P or Fe-Al complexes. Addition of S, however, decreased the plants N:P ratio, indicating an effect of S on the N:P stoichiometry and an effect on the plant's P-demand. Phosphatase activity increased significantly after addition of S, but was not affected by the addition of N or a single drought event. Root phosphatase activity was also positively related to plant tissue N and P concentrations, plant N and P uptake, and plant aboveground biomass, suggesting that the phosphatase enzyme influences P-biogeochemistry. Our results demonstrated that it is difficult to predict the effects of wetland restoration, since the involved mechanisms are not fully understood. Short-term and long-term effects on root phosphatase activity may differ considerably. Additionally, the addition of S can lead to unexpected effects on the biogeochemistry of P. Our results showed that natural resource managers should be careful when restoring degraded fens or preventing desiccation of fen ecosystems. PMID:19101022

  19. Can different affect focus in early stages of therapy predict outcome for different personality disorders within cluster C?

    OpenAIRE

    Eliasson, Lisa M.

    2012-01-01

    Objective: The study compared how specific affect focuses in early stages of treatment predict outcome (SCL-90) for specific cluster C personality disorders. Method: The sample consisted of patients with cluster C personality disorders from a randomized controlled trial comparing 40-sessions of short-term dynamic psychotherapy and cognitive psychotherapy. Thirty-one patients had an avoidant personality disorder (AVPD), 17 patients had an obsessive compulsive personality disorder (OCPD) and 10...

  20. Sugar transport and nitrate reductase activity rate in roots affect plant adaptation to cold and warm climate plants

    OpenAIRE

    Kafkafi, Uzi

    2009-01-01

    Nitrogen metabolism in the root is controlled by 2 fluxes: 1) nitrate intake from the external solution. 2) Transport of sugar from the leaves. Nitrate reduction to ammonium or direct ammonium uptake produce ammonia in the root cell. When the rate of sugar transport to root cells is slower than their sugar consumption for respiration, ammonia will accumulate and the root cells will die from ammonia toxicity. In nature, plants can be defined with regard to the activity of their root nitrate re...

  1. "God of Small Things": Service Interaction's Roots in Regulatory Focus and Affectivity

    OpenAIRE

    Tali Seger-Guttmann; Iris Vilnai-Yavetz

    2014-01-01

    We link regulatory focus, positive and negative affective states, and service behaviors to suggest that, salespersons' service interactions depend on their motivation (promotion- or prevention-focused) and their emotional responses during the service encounter. Based on in-depth interviews with salespeople, a questionnaire applying the concepts of 'skeleton' (the core of exchange relations) and 'tissue' (informal social behaviors) was administered to 90 salespeople in apparel stores. Results ...

  2. Sequencing and transcriptional analysis of the Streptococcus thermophilus histamine biosynthesis gene cluster: factors that affect differential hdcA expression

    DEFF Research Database (Denmark)

    Calles-Enríquez, Marina; Hjort, Benjamin Benn; Andersen, Pia Skov;

    2010-01-01

    produce histamine. The hdc clusters of S. thermophilus CHCC1524 and CHCC6483 were sequenced, and the factors that affect histamine biosynthesis and histidine-decarboxylating gene (hdcA) expression were studied. The hdc cluster began with the hdcA gene, was followed by a transporter (hdcP), and ended with...... the hdcB gene, which is of unknown function. The three genes were orientated in the same direction. The genetic organization of the hdc cluster showed a unique organization among the lactic acid bacterial group and resembled those of Staphylococcus and Clostridium species, thus indicating possible...

  3. Shoot Photosynthesis and Root Growth of Hybrid and Conventional Rice Cultivars as Affected by N and K Levels in the Root Zone

    Institute of Scientific and Technical Information of China (English)

    YANGXIAOE; V.ROEMHELD; 等

    1997-01-01

    Root box experiments were conducted to evaluate the effects of N and NK levels in the root zone on shoot photosynthesis and root growth of hybrid an cultivar of rice (Oryza sativa L.) on two paddy soils (clayey and silty).The results showed that dry matter yields in the hybrid and the cultivar were considerably increased by NK supply,bu the effect was greater for the hybrid.Supply of NK in the root zone significantly increased photosynthetic rate of the lower position leaf and the active green leaf area per plant,in which the effects were much more obvious in the hybrid rice than in the cultivar.High NK supply in the root zone stimulated the root growth,and decreased pH and increased the oxidation zone in the rhizosphere in both entries,but to a greater extent in the hybrid .The results indicated that higher NK levels were needed to maintain higher root activity and shoot photosynthetic capacity in rice,particularly in hybrid rice.

  4. Clustering

    Directory of Open Access Journals (Sweden)

    Jinfei Liu

    2013-04-01

    Full Text Available DBSCAN is a well-known density-based clustering algorithm which offers advantages for finding clusters of arbitrary shapes compared to partitioning and hierarchical clustering methods. However, there are few papers studying the DBSCAN algorithm under the privacy preserving distributed data mining model, in which the data is distributed between two or more parties, and the parties cooperate to obtain the clustering results without revealing the data at the individual parties. In this paper, we address the problem of two-party privacy preserving DBSCAN clustering. We first propose two protocols for privacy preserving DBSCAN clustering over horizontally and vertically partitioned data respectively and then extend them to arbitrarily partitioned data. We also provide performance analysis and privacy proof of our solution..

  5. Symptom severity, affective and somatic symptom clusters predict poorer social cognition performance in current but not remitted major depressive disorder

    OpenAIRE

    Tracy eAir; Michael James Weightman; Bernhard Theodor Baune

    2015-01-01

    The aim of the study was to investigate the social cognitive functioning of participants with major depressive disorder when compared with healthy controls, and to assess the impact of symptom severity and affective and somatic symptom clusters on social cognition. One hundred and eight adult patients with depression (66 remitted and 42 current) and 52 healthy controls were assessed using the Wechsler Advanced Clinical Solutions: Social Perception Subtest, measuring facial affect recognition ...

  6. Symptom severity, affective and somatic symptom clusters predict poorer social cognition performance in current but not remitted major depressive disorder

    Directory of Open Access Journals (Sweden)

    Tracy eAir

    2015-08-01

    Full Text Available The aim of the study was to investigate the social cognitive functioning of participants with major depressive disorder when compared with healthy controls, and to assess the impact of symptom severity and affective and somatic symptom clusters on social cognition. One hundred and eight adult patients with depression (66 remitted and 42 current and 52 healthy controls were assessed using the Wechsler Advanced Clinical Solutions: Social Perception Subtest, measuring facial affect recognition in isolation and in combination with prosody and body language interpretation. While no associations between the diagnostic status (MDD vs controls and any of the social cognition measures were found, severity of depressive and anxious symptoms predicted performance on all social cognition subscales in currently depressed participants, controlling for age, gender, education and psychotropic medication. Moreover, in the current MDD group, an affective depressive symptom cluster was inversely related to performance on the more complex ACS Pairs and Prosody tasks, while a somatic symptom cluster was inversely related to ACS Affect Recognition and Total scores. In contrast, there were no associations between symptom severity or symptom clusters and the WAIS ACS in remitted depression participants. Given the state like nature social deficits in this study, these impairments may cause problems with day to day functioning and have implications in targeted therapeutic interventions.

  7. Constitutive expression of OsIAA9 affects starch granules accumulation and root gravitropic response in Arabidopsis

    Directory of Open Access Journals (Sweden)

    Sha eLuo

    2015-12-01

    Full Text Available Auxin/Indole-3-Acetic Acid (Aux/IAA genes are early auxin response genes ecoding short-lived transcriptional repressors, which regulate auxin signaling in plants by interplay with Auxin Response Factors (ARFs. Most of the Aux/IAA proteins contain four different domains, namely Domain I, Domain II, Domain III and Domain IV. So far all Aux/IAA mutants with auxin-related phenotypes identified in both Arabidopsis and rice (Oryza sativa are dominant gain-of-function mutants with mutations in Domain II of the corresponding Aux/IAA proteins, suggest that Aux/IAA proteins in both Arabidopsis and rice are largely functional redundantly, and they may have conserved functions. We report here the functional characterization of a rice Aux/IAA gene, OsIAA9. RT-PCR results showed that expression of OsIAA9 was induced by exogenously applied auxin, suggesting that OsIAA9 is an auxin response gene. Bioinformatic analysis showed that OsIAA9 has a repressor motif in Domain I, a degron in Domain II, and the conserved amino acid signatures for protein-protein interactions in Domain III and Domain IV. By generating transgenic plants expressing GFP-OsIAA9 and examining florescence in the transgenic plants, we found that OsIAA9 is localized in the nucleus. When transfected into protoplasts isolated from rosette leaves of Arabidopsis, OsIAA9 repressed reporter gene expression, and the repression was partially released by exogenously IAA. These results suggest that OsIAA9 is a canonical Aux/IAA protein. Protoplast transfection assays showed that OsIAA9 interacted ARF5, but not ARF6, 7, 8 and 19. Transgenic Arabidopsis plants expressing OsIAA9 have increased number of lateral roots, and reduced gravitropic response. Further analysis showed that OsIAA9 transgenic Arabidopsis plants accumulated fewer granules in their root tips and the distribution of granules was also affected. Taken together, our study showed that OsIAA9 is a transcriptional repressor, and it regulates

  8. Can star cluster environment affect dust input from massive AGB stars?

    CERN Document Server

    Zhukovska, Svitlana; Henning, Thomas

    2015-01-01

    We examine the fraction of massive asymptotic giant branch (AGB) stars remaining bound in their parent star clusters and the effect of irradiation of these stars by intracluster ultraviolet (UV) field. We employ a set of N-body models of dynamical evolution of star clusters rotating in a galactic potential at the solar galactocentric radius. The cluster models are combined with stellar evolution formulae, a library of stellar spectra, and simple models for SiO photodissociation in circumstellar environment (CSE). The initial stellar masses of clusters are varied from $50\\rm M_\\odot$ to $10^{5}\\rm M_\\odot$. Results derived for individual clusters are combined using a mass distribution function for young star clusters. We find that about 30% of massive AGB stars initially born in clusters become members of the field population, while the rest evolves in star clusters. They are irradiated by strong intracluster UV radiation resulting in the decrease of the photodissociation radius of SiO molecules, in many stars...

  9. EVIDENCE OF CLUSTERING FOR THE MIC-3 ROOT-SPECIFIC GENE FAMILY ASSOCIATED WITH NEMATODE RESISTANCE IN GOSSYPIUM SPP.

    Science.gov (United States)

    MIC-3 is a recently identified gene shown to exhibit increased root-specific expression following nematode infection of plants that are resistant to root-knot nematode (RKN). We cloned and sequenced PCR-amplicons (derived from MIC-3-specific degenerate primers) from individual plant DNAs to [1] det...

  10. Acupuncture at the "Huatuojiaji" point affects nerve root regional interleukin-1 level in a rat model of lumbar nerve root compression

    Institute of Scientific and Technical Information of China (English)

    Yaochi Wu; Junfeng Zhang; Chongmiao Wang; Yanyan Xie; Jinghui Zhou

    2008-01-01

    BACKGROUND: It has been shown that interleukin-1 (IL-1) may cause inflammatory reactions, which stimulate the nerve root of patients with lumbar intervertebral disc protrusion and leads to pain. Whether the clinical curative effects of acupuncture in the treatment of lumbar and leg pain are linked to an inhibition of local IL-1 secretion is unknown.OBJECTIVE: To assess the influence of acupuncture on IL-1, this study was designed to verify the effects of acupuncture at the "Huatuojiaji (Extra)" point on the nerve root in a rat model of lumbar nerve root compression, compared with administration of meloxicam, a non-steroidal anti-inflammatory drug.DESIGN, TIME AND SETTING: Randomized, controlled, molecular biology experiment, performed at the Experimental Center, Sixth People's Hospital Affiliated to Shanghai Jiao Tong University between September 2005 and April 2006.MATERIALS: Forty healthy adult Sprague Dawley rats of either gender were included in this study. The rats were randomly and evenly divided into the following four groups: normal control, model, acupuncture,and meloxicam groups. Lumbar nerve root compression was induced in rats in the model, acupuncture,and meloxicam groups by inserting a specially made silicon rubber slice at the juncture of the L5 nerve root and the dural sac. The acupuncture needle (pattern number N3030, 30#, 1.5 inch) was purchased from Suzhou Medical Appliance Factory, China. IL-1 enzyme linked immunosorbent assay (ELISA) kit was purchased from Santa Cruz Biotechnology, Inc., USA.METHODS: The acupuncture group was acupunctured at the "Huatuojiaji" point, which is lateral to the compressed L5-6 nerve root, with an acupuncture depth of 0.5 cm. There were two treatment courses, each of involved seven 20-minute acupuncture sessions, one session a day. The meloxicam group was administered intragastrically 3.75 mg/kg meloxicam (5 mg meloxicam/10 mL physiological saline). Rats in the normal control group and model group received an

  11. School-based mental health intervention for children in war-affected Burundi: a cluster randomized trial

    OpenAIRE

    Tol, W.A.; Komproe, I. H.; Jordans, M. J. D.; Ndayisaba, A.; Ntamatumba, P.; Sipsma, H.; Smallegange, E.S.; Macy, R.D.; Jong, de, J.

    2014-01-01

    Background: Armed conflicts are associated with a wide range of impacts on the mental health of children and adolescents. We evaluated the effectiveness of a school-based intervention aimed at reducing symptoms of posttraumatic stress disorder, depression, and anxiety (treatment aim); and improving a sense of hope and functioning (preventive aim). Methods: We conducted a cluster randomized trial with 329 children in war-affected Burundi (aged 8 to 17 (mean 12.29 years, standard deviation 1.61...

  12. School-based mental health intervention for children in war-affected Burundi : A cluster randomized trial

    OpenAIRE

    Tol, Wietse A.; Komproe, Ivan H; Jordans, Mark J D; Ndayisaba, Aline; Ntamutumba, Prudence; Sipsma, Heather; Smallegange, Eva S.; Macy, Robert D; de Jong, Joop T. V. M.; Komproe, J

    2014-01-01

    Background: Armed conflicts are associated with a wide range of impacts on the mental health of children and adolescents. We evaluated the effectiveness of a school-based intervention aimed at reducing symptoms of posttraumatic stress disorder, depression, and anxiety (treatment aim); and improving a sense of hope and functioning (preventive aim). Methods: We conducted a cluster randomized trial with 329 children in war-affected Burundi (aged 8 to 17 (mean 12.29 years, standard deviation 1.61...

  13. Sequencing and transcriptional analysis of the streptococcus thermophilus histamine biosynthesis gene cluster: Factors that affect differential hdca expression

    OpenAIRE

    Calles-Enríquez, Marina; Hjort Eriksen, Benjamin; Skov Andersen, Pia; Rattray, F.; Johansen, Annette H.; Fernández García, María; Ladero Losada, Víctor Manuel; Álvarez González, Miguel Ángel

    2010-01-01

    Histamine, a toxic compound that is formed by the decarboxylation of histidine through the action of microbial decarboxylases, can accumulate in fermented food products. From a total of 69 Streptococcus thermophilus strains screened, two strains, CHCC1524 and CHCC6483, showed the capacity to produce histamine. The hdc clusters of S. thermophilus CHCC1524 and CHCC6483 were sequenced, and the factors that affect histamine biosynthesis and histidine-decarboxylating gene (hdcA) expression were st...

  14. Altered Phenylpropanoid Metabolism in the Maize Lc-Expressed Sweet Potato (Ipomoea batatas) Affects Storage Root Development.

    Science.gov (United States)

    Wang, Hongxia; Yang, Jun; Zhang, Min; Fan, Weijuan; Firon, Nurit; Pattanaik, Sitakanta; Yuan, Ling; Zhang, Peng

    2016-01-01

    There is no direct evidence of the effect of lignin metabolism on early storage root development in sweet potato. In this study, we found that heterologous expression of the maize leaf color (Lc) gene in sweet potato increased anthocyanin pigment accumulation in the whole plant and resulted in reduced size with an increased length/width ratio, low yield and less starch content in the early storage roots. RT-PCR analysis revealed dramatic up-regulation of the genes involved in the lignin biosynthesis pathway in developing storage roots, leading to greater lignin content in the Lc transgenic lines, compared to the wild type. This was also evidenced by the enhanced lignification of vascular cells in the early storage roots. Furthermore, increased expression of the β-amylase gene in leaves and storage roots also accelerated starch degradation and increased the sugar use efficiency, providing more energy and carbohydrate sources for lignin biosynthesis in the Lc transgenic sweet potato. Lesser starch accumulation was observed in the developing storage roots at the initiation stage in the Lc plants. Our study provides experimental evidence of the basic carbohydrate metabolism underlying the development of storage roots, which is the transformation of lignin biosynthesis to starch biosynthesis. PMID:26727353

  15. A systematic review of factors affecting children's right to health in cluster randomized trials in Kenya.

    Science.gov (United States)

    Oduwo, Elizabeth; Edwards, Sarah J L

    2014-01-01

    Following the South African case, Treatment Action Campaign and Others v Minister of Health and Others, the use of 'pilot' studies to investigate interventions already proven efficacious, offered free of charge to government, but confined by the government to a small part of the population, may violate children's right to health, and the negative duty on governments not to prevent access to treatment. The applicants challenged a government decision to offer Nevirapine in a few pilot sites when evidence showed Nevirapine significantly reduced HIV transmission rates and despite donor offers of a free supply. The government refused to expand access, arguing they needed to collect more information, and citing concerns about long-term hazards, side effects, resistance and inadequate infrastructure. The court ruled this violated children's right to health and asked the government to immediately expand access. Cluster randomized trials involving children are increasingly popular, and are often used to reduce 'contamination': the possibility that members of a cluster adopt behavior of other clusters. However, they raise unique issues insufficiently addressed in literature and ethical guidelines. This case provides additional crucial guidance, based on a common human rights framework, for the Kenyan government and other involved stakeholders. Children possess special rights, often represent a 'captive' group, and so motivate extra consideration. In a systematic review, we therefore investigated whether cluster trial designs are used to prevent or delay children's access to treatment in Kenya or otherwise inconsistently with children's right to health as outlined in the above case. Although we did not find state sponsored cluster trials, most had significant public sector involvement. Core obligations under children's right to health were inadequately addressed across trials. Few cluster trials reported rationale for cluster randomization, offered post- trial access or

  16. Genome scan identifies a locus affecting gamma-globin expression in human beta-cluster YAC transgenic mice

    Energy Technology Data Exchange (ETDEWEB)

    Lin, S.D.; Cooper, P.; Fung, J.; Weier, H.U.G.; Rubin, E.M.

    2000-03-01

    Genetic factors affecting post-natal g-globin expression - a major modifier of the severity of both b-thalassemia and sickle cell anemia, have been difficult to study. This is especially so in mice, an organism lacking a globin gene with an expression pattern equivalent to that of human g-globin. To model the human b-cluster in mice, with the goal of screening for loci affecting human g-globin expression in vivo, we introduced a human b-globin cluster YAC transgene into the genome of FVB mice . The b-cluster contained a Greek hereditary persistence of fetal hemoglobin (HPFH) g allele resulting in postnatal expression of human g-globin in transgenic mice. The level of human g-globin for various F1 hybrids derived from crosses between the FVB transgenics and other inbred mouse strains was assessed. The g-globin level of the C3HeB/FVB transgenic mice was noted to be significantly elevated. To map genes affecting postnatal g-globin expression, a 20 centiMorgan (cM) genome scan of a C3HeB/F VB transgenics [prime] FVB backcross was performed, followed by high-resolution marker analysis of promising loci. From this analysis we mapped a locus within a 2.2 cM interval of mouse chromosome 1 at a LOD score of 4.2 that contributes 10.4% of variation in g-globin expression level. Combining transgenic modeling of the human b-globin gene cluster with quantitative trait analysis, we have identified and mapped a murine locus that impacts on human g-globin expression in vivo.

  17. Iron fractions in the apoplast of intact root tips of Zea mays L. seedlings affected by nitrogen form

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The effects of ammonium (NH+4- N ) and ni trate (NO-3- N ) Were examined on Fe fractions and FeCN (ferricyanide) reductase activity in intact root tips (0-3 em)of young maize (Zea mays L. cv. Lenz) in solution culture by using short-term experiment under controlled Fe deficiency conditions (containing high HCO-3 concentration in preculture solution). The results showed that Fe( II ) concentrations in root tip apoplast of maize were only 20-40 nmol/g FW which accounted for 7%-13% of total Fe. Most of Fe in root tips existed as Fe(Ⅲ) compounds. Imposition of the roots to NH+4 - N or NO-3 - N for 60 min led to an increase of Fe( II ) in root tip apoplast. NH+4 - N led to an increased concentration of Fe( II ) and exchangeable Fe (Fe( II ) and Fe (III)) in root tips, while NO-3 - N increased FeCN reductaseactivity. The relationship between pH and Fe fractions,FeCN reductase activity was also discussed.``

  18. Can Star Cluster Environment Affect Dust Input From Massive AGB Stars?

    Science.gov (United States)

    Zhukovska, Svitlana; Petrov, Mykola; Henning, Thomas

    2015-09-01

    We examine the fraction of massive asymptotic giant branch (AGB) stars remaining bound in their parent star clusters (SCs) and the effect of irradiation of these stars by an intracluster ultraviolet (UV) field. We employ a set of N-body models of dynamical evolution of SCs rotating in a galactic potential at the solar galactocentric radius. The cluster models are combined with stellar evolution formulae, a library of stellar spectra, and simple models for SiO photodissociation in the circumstellar environment (CSE). The initial stellar masses of clusters are varied from 50{M}⊙ to {10}5{M}⊙ . Results derived for individual clusters are combined using a mass distribution function for young SCs. We find that about 30% of massive AGB stars initially born in clusters become members of the field population, while the rest evolve in SCs. They are irradiated by strong intracluster UV radiation, resulting in the decrease of the photodissociation radius of SiO molecules, in many stars down to the dust formation zone. In the absence of dust shielding, the UV photons penetrate in the CSE deeper than 10{R}* in 64% and deeper than 2{R}* in 42% of all massive AGB stars. If this suppresses subsequent dust formation, the current injection rate of silicate dust from AGB stars in the local Galaxy decreases from 2.2× {10}-4{M}⊙ {{pc}}-2 {{Gyr}}-1 to 1.8× {10}-4{M}⊙ {{pc}}-2 {{Gyr}}-1 at most. A lower revised value of 40% for the expected fraction of presolar silicate grains from massive AGB stars is still too high to explain the non-detection of these grains in meteorites.

  19. Transient Responses of Cell Turgor and Growth of Maize Roots as Affected by Changes in Water Potential.

    Science.gov (United States)

    Frensch, J.; Hsiao, T. C.

    1994-01-01

    Transient responses of cell turgor (P) and root elongation to changes in water potential were measured in maize (Zea mays L.) to evaluate mechanisms of adaptation to water stress. Changes of water potential were induced by exposing roots to solutions of KCl and mannitol (osmotic pressure about 0.3 MPa). Prior to a treatment, root elongation was about 1.2 mm h-1 and P was about 0.67 MPa across the cortex of the expansion zone (3-10 mm behind the root tip). Upon addition of an osmoticum, P decreased rapidly and growth stopped completely at pressure below approximately 0.6 MPa, which indicated that the yield threshold (Ytrans,1) was just below the initial turgor. Turgor recovered partly within the next 30 min and reached a new steady value at about 0.53 MPa. The root continued to elongate as soon as P rose above a new threshold (Ytrans,2) of about 0.45 MPa. The time between Ytrans,1 and Ytrans,2 was about 10 min. During this transition turgor gradients of as much as 0.15 MPa were measured across the cortex. They resulted from a faster rate of turgor recovery of cells deeper inside the tissue compared with cells near the root periphery. Presumably, the phloem was the source of the compounds for the osmotic adjustment. Turgor recovery was restricted to the expansion zone, as was confirmed by measurements of pressure kinetics in mature root tissue. Withdrawal of the osmoticum caused an enormous transient increase of elongation, which was related to only a small initial increase of P. Throughout the experiment, the relationship between root elongation rate and turgor was nonlinear. Consequently, when Y were calculated from steady-state conditions of P and root elongation before and after the osmotic treatment, Yss was only 0.21 MPa and significantly smaller compared with the values obtained from direct measurements (0.42-0.64 MPa). Thus, we strongly emphasize the need for measurements of short-term responses of elongation and turgor to determine cell wall mechanics

  20. How the extinction of extragalactic background light affects surface photometry of galaxies, groups and clusters

    CERN Document Server

    Zackrisson, E; Ostlin, G

    2009-01-01

    The faint regions of galaxies, groups and clusters hold important clues about how these objects formed, and surface photometry at optical and near-infrared wavelengths represents a powerful tool for studying such structures. Here, we identify a hitherto unrecognized problem with this technique, related to how the night sky flux is typically measured and subtracted from astronomical images. While most of the sky flux comes from regions between the observer and the target object, a small fraction - the extragalactic background light (EBL) - comes from behind. We argue that since this part of the sky flux can be subject to extinction by dust present in the galaxy/group/cluster studied, standard reduction procedures may lead to a systematic oversubtraction of the EBL. Even very small amounts of extinction can lead to spurious features in radial surface surface brightness profiles and colour maps of extended objects. We assess the likely impact of this effect on a number of topics in extragalactic astronomy where ...

  1. Overexpression of a Foreign Bt Gene in Cotton Affects the Low-Molecular-Weight Components in Root Exudates

    Institute of Scientific and Technical Information of China (English)

    YAN Wei-Dong; SHI Wei-Ming; LI Bao-Hai; ZHANG Min

    2007-01-01

    Most research in the past using genetically modified crops (GM crops) has focused on the ecological safety of foreign gene (i.e., the gene flow), gene products (for example, Bt (Bacillus thuringiensis) protein), and the safety of transgenic food for humans. In this study, changes in both the species and amounts of low-molecular-weight components in cotton (Gossypium hirsutum L.) root exudates after foreign Bt gene overexpression were investigated under different nutritional conditions. Transgenic cotton containing Bt (Bt-cotton), supplemented with all the mineral nutrients, secreted more organic acids than the wild-type cotton (WT). When nitrogen was removed from the full-nutrient solution, the amount of organic acids secretion of Bt-cotton was lesser than that of WT. The roots of the transgenic cotton secreted lesser amounts of amino acids and soluble sugars than the WT roots in the full-nutrient solution. Deficiencies of P and K caused a large increase in the total amino acid and soluble sugar secretions of both Bt-cotton and WT, with larger increases observed in Bt-cotton. Because transferring the foreign Bt gene into cotton can result in alterations in the components of the root exudates, with the effect varying depending on the nutritional status, the cultivation of genetically modified crops, such as Bt-cotton, in soil environments should be more carefully assessed, and the possible effects as a result of the alterations in the root exudate components should be considered.

  2. Stability of Chloropyromorphite in Ryegrass Rhizosphere as Affected by Root-Secreted Low Molecular Weight Organic Acids

    Science.gov (United States)

    Wei, Wei; Wang, Yu; Wang, Zheng; Han, Ruiming; Li, Shiyin; Wei, Zhenggui; Zhang, Yong

    2016-01-01

    Understanding the stability of chloropyromorphite (CPY) is of considerable benefit for improving risk assessment and remediation strategies in contaminated water and soil. The stability of CPY in the rhizosphere of phosphorus-deficient ryegrass was evaluated to elucidate the role of root-secreted low molecular weight organic acids (LMWOAs) on the dissolution of CPY. Results showed that CPY treatments significantly reduced the ryegrass biomass and rhizosphere pH. The presence of calcium nitrate extractable lead (Pb) and phosphorus (P) suggested that CPY in the rhizosphere could be bioavailable, because P and Pb uptake by ryegrass potentially provided a significant concentration gradient that would promote CPY dissolution. Pb accumulation and translocation in ryegrass was found to be significantly higher in P-sufficient conditions than in P-deficient conditions. CPY treatments significantly enhanced root exudation of LMWOAs irrigated with P-nutrient solution or P-free nutrient solution. Oxalic acid was the dominant species in root-secreted LMWOAs of ryegrass under P-free nutrient solution treatments, suggesting that root-secreted oxalic acid may be the driving force of root-induced dissolution of CPY. Hence, our work, provides clarifying hints on the role of LMWOAs in controlling the stability of CPY in the rhizosphere. PMID:27494023

  3. Seizure Clustering during Drug Treatment Affects Seizure Outcome and Mortality of Childhood-Onset Epilepsy

    Science.gov (United States)

    Sillanpaa, Matti; Schmidt, Dieter

    2008-01-01

    To provide evidence of whether seizure clustering is associated with drug resistance and increased mortality in childhood-onset epilepsy, a prospective, long-term population-based study was performed. One hundred and twenty patients who had been followed since disease onset (average age 37.0 years, SD 7.1, median 40.0, range 11-42; incident cases)…

  4. Does pollinator diversity loss affect pollination: a test with the California poppy and clustered tarweed

    OpenAIRE

    Cen, Henry Jiayin

    2015-01-01

    Pollinators are in decline as a result of human activities such as habitat fragmentation. This study examined the effects of habitat fragmentation and reduced bee diversity on the reproductive performance of California poppy, Eschscholzia californica, and clustered tarweed, Deinandra fasciculata, in the San Diego region. We experimentally introduced potted poppy plants in to scrub fragment habitats and natural reserves. We surveyed the potted poppy plants for floral visitors followed by in si...

  5. Tomato root growth and phosphorus absorption kinetics by tomato plants as affected by phosphorus concentration in nutrient solution

    International Nuclear Information System (INIS)

    To evaluate the effects P concentrations in nutrient solution on root growth and on root physiological characteristics involved in P uptake by tomato Lycopersicon esculentum Mill plants, six seedlings were grown in nutrient solution at initial concentrations of 48.5, 97, 194 and 388 μMP until one day before harvest. They were then transferred to solutions with P at 20 μM and 30 μM, and the depletion curves and Michaelis-Menten parameters were determined. The conclusions were that as P supply increased and as the plant P contents are sufficient for maximum growth, the rate of P uptake tends to be lower. The results also indicate that total P uptake by tomato seedlings depends on the amount of root surface area exposed to P. (M.A.C.)

  6. Altered Phenylpropanoid Metabolism in the Maize Lc-Expressed Sweet Potato (Ipomoea batatas) Affects Storage Root Development

    OpenAIRE

    Hongxia Wang; Jun Yang; Min Zhang; Weijuan Fan; Nurit Firon; Sitakanta Pattanaik; Ling Yuan; Peng Zhang

    2016-01-01

    There is no direct evidence of the effect of lignin metabolism on early storage root development in sweet potato. In this study, we found that heterologous expression of the maize leaf color (Lc) gene in sweet potato increased anthocyanin pigment accumulation in the whole plant and resulted in reduced size with an increased length/width ratio, low yield and less starch content in the early storage roots. RT-PCR analysis revealed dramatic up-regulation of the genes involved in the lignin biosy...

  7. How the extinction of extragalactic background light affects surface photometry of galaxies, groups and clusters

    Science.gov (United States)

    Zackrisson, E.; Micheva, G.; Östlin, G.

    2009-08-01

    The faint regions of galaxies, groups and clusters hold important clues about how these objects formed, and surface photometry at optical and near-infrared wavelengths represents a powerful tool for studying such structures. Here, we identify a hitherto unrecognized problem with this technique, related to how the night sky flux is typically measured and subtracted from astronomical images. While most of the sky flux comes from regions between the observer and the target object, a small fraction - the extragalactic background light (EBL) - comes from behind. We argue that since this part of the sky flux can be subjected to extinction by dust present in the galaxy/group/cluster studied, standard reduction procedures may lead to a systematic oversubtraction of the EBL. Even very small amounts of extinction can lead to spurious features in radial surface brightness profiles and colour maps of extended objects. We assess the likely impact of this effect on a number of topics in extragalactic astronomy where very deep surface photometry is currently attempted, including studies of stellar haloes, starburst host galaxies, disc truncations and diffuse intragroup/intracluster light. We argue that EBL extinction may provide at least a partial explanation for the anomalously red colours reported for the haloes of disc galaxies and for the hosts of local starburst galaxies. EBL extinction effects also mimic truncations in discs with unusually high dust opacities, but are unlikely to be the cause of such features in general. Failure to account for EBL extinction can also give rise to a non-negligible underestimate of intragroup and intracluster light at the faintest surface brightness levels currently probed. Finally, we discuss how EBL extinction effects may be exploited to provide an independent constraint on the surface brightness of the EBL, using a combination of surface photometry and direct star counts.

  8. Soil compaction and organic matter affect conifer seedling nonmycorrhizal and ectomycorrhizal root tip abundance and diversity. Forest Service research paper

    Energy Technology Data Exchange (ETDEWEB)

    Amaranthus, M.P.; Page-Dumroese, D.; Harvey, A.; Cazares, E.; Bednar, L.F.

    1996-05-01

    Three levels of organic matter removal (bole only; bole and crowns; and bole, crowns, and forest floor) and three levels of mechanical soil compaction (no compaction, moderate compaction, and severe soil compaction) were studied as they influence Douglas-fir (Pseudotsuga menziesii var. glauca (Beissn.) Franco) and western white pine (Pinus monticola Dougl. ex D. Don) seedlings following outplanting. Moderate and severe soil compaction significantly reduced nonmycorrhizal root tip abundance on both Douglas-fir and western white pine seedlings (p less than or equal to 0.05). Ectomycorrhizal root tip abundance was significantly reduced on Douglas-fir seedlings in severely compacted areas with bole and crowns and bole, crowns, and forest floor removed. Ectomycorrhizal diversity also was significantly reduced on Douglas-fir seedlings in all severely compacted areas.

  9. Bioavailable concentrations of germanium and rare earth elements in soil as affected by low molecular weight organic acids and root exudates

    Science.gov (United States)

    Wiche, Oliver; Székely, Balázs; Kummer, Nicolai-Alexeji; Heinemann, Ute; Tesch, Silke; Heilmeier, Hermann

    2014-05-01

    , lanthan, neodymium, gadolinium and erbium in the rhizosphere and therefore the enhancement of bioavailability of the mentioned elements to plants. Based on the suction cup experiment we conclude that in vertical soil profile the bioavailable germanium is heavily affected by the activity of exudates, as the complexation processes of germanium take place at the root zone and below affected by the interplay of the infiltration of citric acid solutions and the actually produced exudates. These studies have been carried out in the framework of the PhytoGerm project, financed by the Federal Ministry of Education and Research, Germany. BS contributed as an Alexander von Humboldt Research Fellow. The authors are grateful to students and laboratory assistants contributing in the field work and sample preparation.

  10. How Do Rare Earth Elements (Lanthanoids Affect Root Development and Protocorm-Like Body Formation in Hybrid CYMBIDIUM?

    Directory of Open Access Journals (Sweden)

    Teixeira da Silva Jaime A.

    2014-09-01

    Full Text Available Only few studies in the plant tissue culture literature have examined the impact of lanthanoids, or rare earth elements, on in vitro plant organogenesis. In this study, using a model plant, hybrid Cymbidium Twilight Moon ‘Day Light’, the impact of six lanthanoids (lanthanum (III nitrate hexahydrate (La(NO33 · 6H2O, cerium (III nitrate hexahydrate (Ce(NO33 · 6H2O, neodymium (III nitrate hexahydrate (Nd(NO33 · 6H2O, praseodymium (III nitrate hexahydrate (Pr(NO33 · 6H2O, samarium (III nitrate hexahydrate (Sm(NO33 · 6H2O, gadolinium (III nitrate hexahydrate (Gd(NO33 · 6H2O on new protocorm-like body (neo-PLB formation on Teixeira Cymbidium (TC medium was examined. 0 (control, 1, 2, 4 and 8 mg·dm-3 of each lanthanoid was tested. All lanthanoids could produce more neo-PLBs and neo-PLB fresh weight than TC medium lacking plant growth regulators (PGRs, suggesting some PGR-like ability of lanthanoids, although PLB-related traits (percentage of half-PLBs forming neo-PLBs; number of neo-PLBs formed per half-PLB; fresh weight of half-PLB + neo-PLBs was always significantly lower than TC medium containing PGRs. Except for Gd, all other lanthanoids had no negative impact on the number of new leaves from neo-PLB-derived shoots, but all lanthanoids showed a significantly lower plant height, shoot fresh weight and shoot dry weight and, in most cases, SPAD (chlorophyll content value. In addition, using the same concentration of the six lanthanoids, the ability to fortify root formation of neo-PLB-derived plantlets was also assessed. Except for Sm, all other lanthanoids significantly increased the number of roots, root fresh and dry weight.

  11. Factors affecting on bond strength of glass fiber post cemented with different resin cements to root canal

    Science.gov (United States)

    Clavijo, V. R. G.; Bandéca, M. C.; Calixto, L. R.; Nadalin, M. R.; Saade, E. G.; Oliveira-Junior, O. B.; Andrade, M. F.

    2009-09-01

    Luting materials provides the retention of endodontic post. However, the failures of endodontic posts predominantly occurred are the losses of retention. Thus, the alternating use to remove the smear layer, open the dentine tubules, and/or etch the inter-tubular dentine can be provided by EDTA. This study was performed to evaluate effect of EDTA on bond strength of glass fiber post cemented with different resin cements to root canal. Fifty bovine incisors were selected and the crowns were removed to obtain a remaining 14-mm-height root. The roots were randomly distributed into five groups: GI: RelyX™ ARC/LED; GII: RelyX™ U100/LED; GIII EDTA/RelyX™ U100/LED; GIV: Multilink™; and GV: EDTA/Multlink™. After endodontic treatment, the post space was prepared with the drills designated for the quartz-coated-carbon-fiber post Aestheti-Post®. Before application of resin cements, root canals were irrigated with 17% EDTA (GIII and GV) during 1 min, rinsed with distilled water and dried using paper points. The light-cured materials were light-activated with UltraLume LED 5 (Ultradent, South Jordan, Utah) with power density of 1315 mW/cm2. Specimens were perpendicularly sectioned into approximately 1 mm thick sections and the stubs were performed on Universal Testing Machine. The analysis of variance (ANOVA) and Tukey’s post-hoc tests showed significant statistical different between RelyX™ ARC (GI) and RelyX™ U100 independent of the pre-treatment (GII to GIII) ( P 0.05) to all resin cements between the Cervical to Apical regions (GI to GV). The use of 17% EDTA showed no difference significant between the resin cements evaluated (GII to GIII; GIV to GV). Within the limitations of the current study, it can be concluded that the use of EDTA did not provide efficiency on bond strength. The RelyX™ ARC showed higher bond strength values than RelyX™ U100.

  12. Does training frequency and supervision affect compliance, performance and muscular health? A cluster randomized controlled trial.

    Science.gov (United States)

    Dalager, Tina; Bredahl, Thomas G V; Pedersen, Mogens T; Boyle, Eleanor; Andersen, Lars L; Sjøgaard, Gisela

    2015-10-01

    The aim was to determine the effect of one weekly hour of specific strength training within working hours, performed with the same total training volume but with different training frequencies and durations, or with different levels of supervision, on compliance, muscle health and performance, behavior and work performance. In total, 573 office workers were cluster-randomized to: 1 WS: one 60-min supervised session/week, 3 WS: three 20-min supervised sessions/week, 9 WS: nine 7-min supervised sessions/week, 3 MS: three 20-min sessions/week with minimal supervision, or REF: a reference group without training. Outcomes were diary-based compliance, total training volume, muscle performance and questionnaire-based health, behavior and work performance. Comparisons were made among the WS training groups and between 3 WS and 3 MS. If no difference, training groups were collapsed (TG) and compared with REF. Results demonstrated similar degrees of compliance, mean(range) of 39(33-44)%, and total training volume, 13.266(11.977-15.096)kg. Musculoskeletal pain in neck and shoulders were reduced with approx. 50% in TG, which was significant compared with REF. Only the training groups improved significantly their muscle strength 8(4-13)% and endurance 27(12-37)%, both being significant compared with REF. No change in workability, productivity or self-rated health was demonstrated. Secondary analysis showed exercise self-efficacy to be a significant predictor of compliance. Regardless of training schedule and supervision, similar degrees of compliance were shown together with reduced musculoskeletal pain and improved muscle performance. These findings provide evidence that a great degree of flexibility is legitimate for companies in planning future implementation of physical exercise programs at the workplace. ClinicalTrials.gov, number NCT01027390. PMID:25816746

  13. Metabolic and transcriptional response of central metabolism affected by root endophytic fungus Piriformospora indica under salinity in barley.

    Science.gov (United States)

    Ghaffari, Mohammad Reza; Ghabooli, Mehdi; Khatabi, Behnam; Hajirezaei, Mohammad Reza; Schweizer, Patrick; Salekdeh, Ghasem Hosseini

    2016-04-01

    The root endophytic fungus Piriformospora indica enhances plant adaptation to environmental stress based on general and non-specific plant species mechanisms. In the present study, we integrated the ionomics, metabolomics, and transcriptomics data to identify the genes and metabolic regulatory networks conferring salt tolerance in P. indica-colonized barley plants. To this end, leaf samples were harvested at control (0 mM NaCl) and severe salt stress (300 mM NaCl) in P. indica-colonized and non-inoculated barley plants 4 weeks after fungal inoculation. The metabolome analysis resulted in an identification of a signature containing 14 metabolites and ions conferring tolerance to salt stress. Gene expression analysis has led to the identification of 254 differentially expressed genes at 0 mM NaCl and 391 genes at 300 mM NaCl in P. indica-colonized compared to non-inoculated samples. The integration of metabolome and transcriptome analysis indicated that the major and minor carbohydrate metabolism, nitrogen metabolism, and ethylene biosynthesis pathway might play a role in systemic salt-tolerance in leaf tissue induced by the root-colonized fungus. PMID:26951140

  14. Volcanology of Tuzo pipe (Gahcho Kué cluster) — Root-diatreme processes re-interpreted

    Science.gov (United States)

    Seghedi, I.; Maicher, D.; Kurszlaukis, S.

    2009-11-01

    The Middle Cambrian (~ 540 Ma) Gahcho Kué Kimberlite Field is situated about 275 km ENE of Yellowknife, NWT, Canada. The kimberlites were emplaced into 2.6 Ga Archean granitic rocks of the Yellowknife Supergroup. Four larger kimberlite bodies (5034, Tesla, Tuzo, and Hearne) as well as a number of smaller pipes and associated sheets occur in the field. In plan view, the Tuzo pipe has a circular outline at the surface, and it widens towards deeper levels. The pipe infill consists of several types of coherent and fragmental kimberlite facies. Coherent or apparent coherent (possibly welded) kimberlite facies dominate at depth, but also occur at shallow levels, as dikes intruded late in the eruptive sequence or individual coherent kimberlite clasts. The central and shallower portions of the pipe consist of several fragmental kimberlite varieties that are texturally classified as Tuffisitic Kimberlites. The definition, geometry and extent of the geological units are complex and zones controlled by vertical elements are most significant. The fluidal outlines of some of the coherent kimberlite clasts suggest that at least some are the product of disruption of magma that was in a semi-plastic state or even of welded material. Ragged clasts at low levels are inferred to form part of a complex peperite-like system that intrudes the base of the root zone. A variable, often high abundance of local wall-rock xenoliths between and within the kimberlite phases is observed, varying in size from sub-millimeter to several tens of meters. Wall-rock fragments are common at all locations within the pipe but are especially frequent in a domain with a belt-like geometry between 120 and 200 m depth in the pipe. Steeply outward-dipping bedded deposits made up of wall-rock fragments occur in deep levels of the pipe and are especially common under the downward-widening roof segments. The gradational contact relationships of these deposits with the surrounding kimberlite-bearing rocks as well

  15. Phenotypic instability of Arabidopsis alleles affecting a disease Resistance gene cluster

    Directory of Open Access Journals (Sweden)

    Richards Eric J

    2008-04-01

    Full Text Available Abstract Background Three mutations in Arabidopsis thaliana strain Columbia – cpr1, snc1, and bal – map to the RPP5 locus, which contains a cluster of disease Resistance genes. The similar phenotypes, gene expression patterns, and genetic interactions observed in these mutants are related to constitutive activation of pathogen defense signaling. However, these mutant alleles respond differently to various conditions. Exposure to mutagens, such as ethyl methanesulfonate (EMS and γ-irradiation, induce high frequency phenotypic instability of the bal allele. In addition, a fraction of the bal and cpr1 alleles segregated from bal × cpr1 F1 hybrids also show signs of phenotypic instability. To gain more insight into the mechanism of phenotypic instability of the bal and cpr1 mutations, we systematically compared the behavior of these unusual alleles with that of the missense gain-of-function snc1 allele in response to DNA damage or passage through F1 hybrids. Results We found that the cpr1 allele is similar to the bal allele in its unstable behavior after EMS mutagenesis. For both the bal and cpr1 mutants, destabilization of phenotypes was observed in more than 10% of EMS-treated plants in the M1 generation. In addition, exceptions to simple Mendelian inheritance were identified in the M2 generation. Like cpr1 × bal F1 hybrids, cpr1 × snc1 F1 hybrids and bal × snc1 F1 hybrids exhibited dwarf morphology. While only dwarf F2 plants were produced from bal × snc1 F1 hybrids, about 10% wild-type F2 progeny were produced from cpr1 × snc1 F1 hybrids, as well as from cpr1 × bal hybrids. Segregation analysis suggested that the cpr1 allele in cpr1 × snc1 crosses was destabilized during the late F1 generation to early F2 generation. Conclusion With exposure to EMS or different F1 hybrid contexts, phenotypic instability is induced for the bal and cpr1 alleles, but not for the snc1 allele. Our results suggest that the RPP5 locus can adopt different

  16. Tityus bahiensis toxin IV-5b selectively affects Na channel inactivation in chick dorsal root ganglion neurons.

    Science.gov (United States)

    Trequattrini, C; Zamudio, F Z; Petris, A; Prestipino, G; Possani, L D; Franciolini, F

    1995-09-01

    A novel toxin was isolated from the venom of the Brazilian scorpion Tityus (T.) bahiensis. The N-terminal amino acid sequence of this toxin was shown to be 80% identical to the corresponding segment of T. serrulatus toxin IV-5. The new toxin was thus named toxin IV-5b. Toxin IV-5b was found to markedly slow inactivation of Na channel in dorsal root ganglion neurons from chick embryo. By contrast, Na channel activation was only negligibly delayed, and deactivation completely unaffected. Similarly unaffected by the toxin were K and Ca currents. The slowing effect of the toxin starts to appear at concentrations of c. 80 nM, and shows a KD of 143 nM. With a toxin concentration of 2.4 microM, the Na channel inactivation time constant was increased c. 3-fold with respect to the control. The slowing of inactivation was voltage dependent, and increased with depolarization. PMID:7553331

  17. Root-zone acidity and nitrogen source affects Typha latifolia L. growth and uptake kinetics of ammonium and nitrate.

    Science.gov (United States)

    Brix, Hans; Dyhr-Jensen, Kirsten; Lorenzen, Bent

    2002-12-01

    The NH(4)(+) and NO(3)(-) uptake kinetics by Typha latifolia L. were studied after prolonged hydroponics growth at constant pH 3.5, 5.0, 6.5 or 7.0 and with NH(4)(+) or NO(3)(-) as the sole N-source. In addition, the effects of pH and N source on H(+) extrusion and adenine nucleotide content were examined. Typha latifolia was able to grow with both N sources at near neutral pH levels, but the plants had higher relative growth rates, higher tissue concentrations of the major nutrients, higher contents of adenine nucleotides, and higher affinity for uptake of inorganic nitrogen when grown on NH(4)(+). Growth almost completely stopped at pH 3.5, irrespective of N source, probably as a consequence of pH effects on plasma membrane integrity and H(+) influx into the root cells. Tissue concentrations of the major nutrients and adenine nucleotides were severely reduced at low pH, and the uptake capacity for inorganic nitrogen was low, and more so for NO(3)(-)-fed than for NH(4)(+)-fed plants. The maximum uptake rate, V(max), was highest for NH(4)(+) at pH 6.5 (30.9 micro mol h(-1) g(-1) root dry weight) and for NO(3)(-) at pH 5.0 (31.7 micro mol h(-1) g(-1) root dry weight), and less than 10% of these values at pH 3.5. The affinity for uptake as estimated by the half saturation constant, K((1/2)), was lowest at low pH for NH(4)(+) and at high pH for NO(3)(-). The changes in V(max) and K((1/2)) were thus consistent with the theory of increasing competition between cations and H(+) at low pH and between anions and OH(-) at high pH. C(min) was independent of pH, but slightly higher for NO(3)(-) than for NH(4)(+) (C(min)(NH(4)(+)) approximately 0.8 mmol m(-3); C(min)(NO(3)(-)) approximately 2.8 mmol m(-3)). The growth inhibition at low pH was probably due to a reduced nutrient uptake and a consequential limitation of growth by nutrient stress. Typha latifolia seems to be well adapted to growth in wetland soils where NH(4)(+) is the prevailing nitrogen compound, but very low p

  18. Root development under drought stress

    OpenAIRE

    Franco Leemhuis, José Antonio

    2011-01-01

    Serving as interfaces between plant and the soil, roots are much more exposed to drought stress than the upper plant parts. Therefore, the root system can be as affected, or even more affected, than the aerial parts of the plant for drought stress (Franco et al., 2011). Nevertheless, the influence of this stress on root activity and development has been much less studied. Undoubtedly, this is due to limitations on accessibility for root observations; being studies on root system dynamics espe...

  19. Desenvolvimento radicular do algodoeiro em resposta à localização do fertilizante Cotton root development as affected by fertilizer placement

    Directory of Open Access Journals (Sweden)

    Fábio Suano de Souza

    2007-04-01

    Full Text Available A utilização de adubos pode-se tornar prejudicial caso o fertilizante não seja localizado adequadamente. No presente trabalho foram estudados o crescimento radicular do algodoeiro (Gossypium hirsutum, o crescimento inicial e a nutrição da planta, considerando o local de aplicação do fertilizante. O estudo foi realizado em vasos com parede de vidro. O fertilizante foi colocado a 5,0 cm abaixo e 0,0, 2,5, 5,0 e 10,0 cm ao lado das sementes. O crescimento radicular foi avaliado a cada três dias e, aos 21 dias após a emergência, as plantas foram coletadas, sendo avaliada a produção de matéria seca e a absorção de macronutrientes. A aplicação de fertilizante proporcionou crescimento inicial mais vigoroso do sistema radicular mesmo em solo previamente corrigido e adubado, o que é importante no estabelecimento da cultura. Somente houve bom crescimento inicial do sistema radicular e da parte aérea do algodoeiro quando o fertilizante foi aplicado de 5,0 a 10,0 cm ao lado e 5,0 cm abaixo das sementes.Unless fertilizer is properly placed in the soil it can be harmful. This experiment was conducted to study cotton (Gossypium hirsutum root growth and initial plant development and nutrition as affected by fertilizer placement. Cotton plants were grown in pots with a glass wall. The fertilizer was applied 5.0 cm under the seed row and 0, 2.5, 5.0 and 10.0 cm beside the seed row. Root growth was evaluated every 3 days, and 21 days after emergence the plants were harvested. Dry matter production and macronutrient absorption were evaluated. Even in previously limed and fertilized soil, localized fertilizer application reinforced the initial growth of cotton roots, which is very important for a good crop establishment in the field. Normal root growth and adequate initial plant development was only observed when the fertilizer was placed 5.0 cm below and from 5.0 to 10.0 cm distance from the seed row.

  20. Analysis of variables affecting unemployment rate and detecting for cluster in West Java, Central Java, and East Java in 2012

    Science.gov (United States)

    Samuel, Putra A.; Widyaningsih, Yekti; Lestari, Dian

    2016-02-01

    The objective of this study is modeling the Unemployment Rate (UR) in West Java, Central Java, and East Java, with rate of disease, infant mortality rate, educational level, population size, proportion of married people, and GDRP as the explanatory variables. Spatial factors are also considered in the modeling since the closer the distance, the higher the correlation. This study uses the secondary data from BPS (Badan Pusat Statistik). The data will be analyzed using Moran I test, to obtain the information about spatial dependence, and using Spatial Autoregressive modeling to obtain the information, which variables are significant affecting UR and how great the influence of the spatial factors. The result is, variables proportion of married people, rate of disease, and population size are related significantly to UR. In all three regions, the Hotspot of unemployed will also be detected districts/cities using Spatial Scan Statistics Method. The results are 22 districts/cities as a regional group with the highest unemployed (Most likely cluster) in the study area; 2 districts/cities as a regional group with the highest unemployed in West Java; 1 district/city as a regional groups with the highest unemployed in Central Java; 15 districts/cities as a regional group with the highest unemployed in East Java.

  1. Forecasting electricity consumption by clustering data in order to decline the periodic variable's affects and simplification the pattern

    International Nuclear Information System (INIS)

    Electricity demand forecasting is known as one of the most important challenges in managing supply and demand of electricity. Consumption pattern of electricity has been affected by some social, economical and environmental factors by which the pattern will form various seasonal, monthly, daily and hourly complex variations. Diversity and complexity in consumption pattern of electricity have been leading to the extension of the complicated models. Many attempts have been made to find the best estimation for electricity consumption. These studies have been tried to forecast the demand in two levels: (1) Macro economic decision making and (2) Engineering and middle management. In this research an attempt has been made to introduce a method for pre-preparing data and for developing a model that could be applied in both the mentioned levels. By clustering primary data and by eliminating the periodic variance in our study, the complicated pattern is decomposed to a set of simple patterns which could be easily analyzed with conventional tools in both the levels

  2. Measuring human rights violations in a conflict-affected country: results from a nationwide cluster survey in Central African Republic

    Directory of Open Access Journals (Sweden)

    Roberts Les

    2011-03-01

    Full Text Available Abstract Background Measuring human rights violations is particularly challenging during or after armed conflict. A recent nationwide survey in the Central African Republic produced estimates of rates of grave violations against children and adults affected by armed conflict, using an approach known as the "Neighborhood Method". Methods In June and July, 2009, a random household survey was conducted based on population estimates from the 2003 national census. Clusters were assigned systematically proportional to population size. Respondents in randomly selected households were interviewed regarding incidents of killing, intentional injury, recruitment into armed groups, abduction, sexual abuse and rape between January 1, 2008 and the date of interview, occurring in their homes' and those of their three closest neighbors. Results Sixty of the selected 69 clusters were surveyed. In total, 599 women were interviewed about events in 2,370 households representing 13,669 persons. Estimates of annual rates of each violation occurring per 1000 people in each of two strata are provided for children between the ages of five and 17, adults 18 years of age and older and the entire population five years and older, along with a combined and weighted national rate. The national rates for children age five to 17 were estimated to be 0.98/1000/year (95% CI: 0.18 - 1.78 for recruitment, 2.56/1000/year (95% CI: 1.50 - 3.62 for abduction, 1.13/1000/year (95% CI: 0.33 - 1.93 for intentional injury, 10.72/1000 girls/year (95% CI: 7.40 - 14.04 for rape, and 4.80/1000 girls/year (95% CI: 2.61 - 6.00 for sexual abuse. No reports of any violation against a person under the age of five were recorded and there were no reports of rape or sexual abuse of males. No children were reported to have been killed during the recall period. Rape and abduction were the most frequently reported events. Conclusions The population-based figures greatly augment existing information on

  3. Measuring human rights violations in a conflict-affected country: results from a nationwide cluster survey in Central African Republic

    Science.gov (United States)

    2011-01-01

    Background Measuring human rights violations is particularly challenging during or after armed conflict. A recent nationwide survey in the Central African Republic produced estimates of rates of grave violations against children and adults affected by armed conflict, using an approach known as the "Neighborhood Method". Methods In June and July, 2009, a random household survey was conducted based on population estimates from the 2003 national census. Clusters were assigned systematically proportional to population size. Respondents in randomly selected households were interviewed regarding incidents of killing, intentional injury, recruitment into armed groups, abduction, sexual abuse and rape between January 1, 2008 and the date of interview, occurring in their homes' and those of their three closest neighbors. Results Sixty of the selected 69 clusters were surveyed. In total, 599 women were interviewed about events in 2,370 households representing 13,669 persons. Estimates of annual rates of each violation occurring per 1000 people in each of two strata are provided for children between the ages of five and 17, adults 18 years of age and older and the entire population five years and older, along with a combined and weighted national rate. The national rates for children age five to 17 were estimated to be 0.98/1000/year (95% CI: 0.18 - 1.78) for recruitment, 2.56/1000/year (95% CI: 1.50 - 3.62) for abduction, 1.13/1000/year (95% CI: 0.33 - 1.93) for intentional injury, 10.72/1000 girls/year (95% CI: 7.40 - 14.04) for rape, and 4.80/1000 girls/year (95% CI: 2.61 - 6.00) for sexual abuse. No reports of any violation against a person under the age of five were recorded and there were no reports of rape or sexual abuse of males. No children were reported to have been killed during the recall period. Rape and abduction were the most frequently reported events. Conclusions The population-based figures greatly augment existing information on human rights violations in

  4. Structure-function relationships affecting the sensing mechanism of monolayer-protected cluster doped xerogel amperometric glucose biosensors.

    Science.gov (United States)

    DiPasquale, Luke T; Poulos, Nicholas G; Hall, Jackson R; Minocha, Aastha; Bui, Tram Anh; Leopold, Michael C

    2015-07-15

    A systematic study of the structure-function relationships critical to understanding the sensing mechanism of 1st generation amperometric glucose biosensors with an embedded nanoparticle (NP) network is presented. Xerogel-based films featuring embedded glucose oxidase enzyme and doped with alkanethiolate-protected gold NPs, known as monolayer protected clusters (MPCs), exhibit significantly enhanced performance compared to analogous systems without NPs including higher sensitivity, faster response time, and extended linear/dynamic ranges. The proposed mechanism involves diffusion of the glucose to glucose oxidase within the xerogel, enzymatic reaction production of H2O2 with subsequent diffusion to the embedded network of MPCs where it is oxidized, an event immediately reported via fast electron transfer (ET) through the MPC system to the working electrode. Various aspects of the film construct and strategy are systematically probed using amperometry, voltammetry, and solid-state electronic conductivity measurements, including the effects of MPC peripheral chain length, MPC functionalization via place-exchange reaction, MPC core size, and the MPC density or concentration within the xerogel composite films. The collective results of these experiments support the proposed mechanism and identify interparticle spacing and the electronic communication through the MPC network is the most significant factor in the sensing scheme with the diffusional aspects of the mechanism that may be affected by film/MPC hydrophobicity and functionality (i.e., glucose and H2O2 diffusion) shown to be less substantial contributors to the overall enhanced performance. Understanding the structure-function relationships of effective sensing schemes allows for the employment of the strategy for future biosensor design toward clinically relevant targets. PMID:25819004

  5. Capturing Arabidopsis Root Architecture Dynamics with root-fit Reveals Diversity in Responses to Salinity1[W][OPEN

    Science.gov (United States)

    Julkowska, Magdalena M.; Hoefsloot, Huub C.J.; Mol, Selena; Feron, Richard; de Boer, Gert-Jan; Haring, Michel A.; Testerink, Christa

    2014-01-01

    The plant root is the first organ to encounter salinity stress, but the effect of salinity on root system architecture (RSA) remains elusive. Both the reduction in main root (MR) elongation and the redistribution of the root mass between MRs and lateral roots (LRs) are likely to play crucial roles in water extraction efficiency and ion exclusion. To establish which RSA parameters are responsive to salt stress, we performed a detailed time course experiment in which Arabidopsis (Arabidopsis thaliana) seedlings were grown on agar plates under different salt stress conditions. We captured RSA dynamics with quadratic growth functions (root-fit) and summarized the salt-induced differences in RSA dynamics in three growth parameters: MR elongation, average LR elongation, and increase in number of LRs. In the ecotype Columbia-0 accession of Arabidopsis, salt stress affected MR elongation more severely than LR elongation and an increase in LRs, leading to a significantly altered RSA. By quantifying RSA dynamics of 31 different Arabidopsis accessions in control and mild salt stress conditions, different strategies for regulation of MR and LR meristems and root branching were revealed. Different RSA strategies partially correlated with natural variation in abscisic acid sensitivity and different Na+/K+ ratios in shoots of seedlings grown under mild salt stress. Applying root-fit to describe the dynamics of RSA allowed us to uncover the natural diversity in root morphology and cluster it into four response types that otherwise would have been overlooked. PMID:25271266

  6. Clustering, haplotype diversity and locations of MIC-3: a unique root-specific defense-related gene family in upland cotton (Gossypium hirsutum L.)

    Science.gov (United States)

    MIC-3-related genes of cotton (Gossypium spp.) were identified and shown to have root-specific expression, associated with pathogen defense-related function and specifically increased expression in root-knot nematode (RKN) resistant plants after nematode infection. Here we cloned and sequenced MIC-...

  7. PATTERN OF ROOTING AND GROWTH OF CUTTINGS OF SOME SPECIES OF INSECTICIDAL AND MEDICINAL IMPORTANCE AS AFFECTED BY GROWTH PROMOTING SUBSTANCES

    OpenAIRE

    Obi, E.A; Aiyelari, O..P; Agele , S.O

    2013-01-01

    This study was designed to examine the effects of promoting substances on bud retention, rooting and plantlets survival of rooted cuttings on selected tree species using growth promoting substances. Stem cuttings were treated with rooting-promoting substances, planted in plastic pots filled with top soil and arranged using a completely randomized design (CRD) in a screen house. Stem cuttings of pepper fruit, guava, bush mango and cashew were obtained from the Teaching and Research Farm, Feder...

  8. The D-type cyclin CYCD4;1 modulates lateral root density in Arabidopsis by affecting the basal meristem region

    OpenAIRE

    Nieuwland, Jeroen; Maughan, Spencer; Dewitte, Walter; Scofield, Simon; Sanz, Luis; Murray, James A.H.

    2009-01-01

    Root cell division occurs primarily in the apical meristem, from which cells are displaced into the basal meristem, where division decreases and cell length increases before the final differentiation zone. The organization of the root in concentric files implies coordinated division and differentiation of cell types, including the xylem pole pericycle cells, which uniquely can resume division to initiate lateral roots (LR). Here, we show that D-type cyclin CYCD4;1 is expressed in meristematic...

  9. Carbon Allocation into Different Fine-Root Classes of Young Abies alba Trees Is Affected More by Phenology than by Simulated Browsing.

    Science.gov (United States)

    Endrulat, Tina; Buchmann, Nina; Brunner, Ivano

    2016-01-01

    Abies alba (European silver fir) was used to investigate possible effects of simulated browsing on C allocation belowground by 13CO2 pulse-labelling at spring, summer or autumn, and by harvesting the trees at the same time point of the labelling or at a later season for biomass and for 13C-allocation into the fine-root system. Before budburst in spring, the leader shoots and 50% of all lateral shoots of half of the investigated 5-year old Abies alba saplings were clipped to simulate browsing. At harvest, different fine-root classes were separated, and starch as an important storage compartment was analysed for concentrations. The phenology had a strong effect on the allocation of the 13C-label from shoots to roots. In spring, shoots did not supply the fine-roots with high amounts of the 13C-label, because the fine-roots contained less than 1% of the applied 13C. In summer and autumn, however, shoots allocated relatively high amounts of the 13C-label to the fine roots. The incorporation of the 13C-label as structural C or as starch into the roots is strongly dependent on the root type and the root diameter. In newly formed fine roots, 3-5% of the applied 13C was incorporated, whereas 1-3% in the ≤0.5 mm root class and 1-1.5% in the >0.5-1.0 mm root class were recorded. Highest 13C-enrichment in the starch was recorded in the newly formed fine roots in autumn. The clipping treatment had a significant positive effect on the amount of allocated 13C-label to the fine roots after the spring labelling, with high relative 13C-contents observed in the ≤0.5 mm and the >0.5-1.0 mm fine-root classes of clipped trees. No effects of the clipping were observed after summer and autumn labelling in the 13C-allocation patterns. Overall, our data imply that the season of C assimilation and, thus, the phenology of trees is the main determinant of the C allocation from shoots to roots and is clearly more important than browsing. PMID:27123860

  10. Characterization of plant growth promoting rhizobacteria isolated from root system of sunflower (helianthus annus l) grown under salt affected area of pakistan

    International Nuclear Information System (INIS)

    Plant growth promoting rhizobacteria (PGPR) directly promote plant growth by providing indole-3-acetic acid (IAA), solubilization of inorganic phosphates, nitrogen fixation and siderophores and other organic acid production, whereas indirectly support plant growth by suppressing plant pathogens. The objective of this study was isolation and characterization of bacterial strains from rhizosphere, endosphere and rhizoplane of sunflower. Thirty six bacterial strains were selected out of 44 from plant root samples along with rhizospheric soil, collected from different salt affected areas of Central Punjab (Pakistan). Selected bacterial strains were characterized morphologically as well as biochemically at National Agricultural Research Centre, Islamabad during 2011-13. It was observed that all isolates produced IAA, whereas 14 strains were declared as phosphate solubilizing bacteria (PSB), eight isolates exhibited antifungal characteristics, 30 were nitrogen fixer and all of them were gram -ve. During biochemical characterization of bacterial isolates KS 15 and KS 8 produced the highest indole acetic acid whereas KS 15 and KS 17 indicated maximum phosphate solubilization (PS) among all isolated strains. The bacterial strains KS 10 and KS 44 showed maximum bio-control activity (fungal growth inhibition) than other isolated strains. (author)

  11. Outcomes and moderators of a preventive school-based mental health intervention for children affected by war in Sri Lanka: a cluster randomized trial

    OpenAIRE

    TOL, WIETSE A.; KOMPROE, IVAN H.; Jordans, Mark J. D.; Vallipuram, Anavarathan; Sipsma, Heather; SIVAYOKAN, SAMBASIVAMOORTHY; Macy, Robert D; de Jong, Joop T.

    2012-01-01

    We aimed to examine outcomes, moderators and mediators of a preventive school-based mental health intervention implemented by paraprofessionals in a war-affected setting in northern Sri Lanka. A cluster randomized trial was employed. Subsequent to screening 1,370 children in randomly selected schools, 399 children were assigned to an intervention (n=199) or waitlist control condition (n=200). The intervention consisted of 15 manualized sessions over 5 weeks of cognitive behavioral techniques ...

  12. Roots Revisited.

    Science.gov (United States)

    Hughes, Barnabas

    1998-01-01

    Offers historical information about square roots. Presents three different methods--Hero's method, visual method, and remainder method--which can be used to teach the finding of square roots and one method for determining cube roots. (ASK)

  13. Root systems and generalized associahedra

    OpenAIRE

    Fomin, Sergey; Reading, Nathan

    2005-01-01

    These lecture notes for the IAS/Park City Graduate Summer School in Geometric Combinatorics (July 2004) provide an overview of root systems, generalized associahedra, and the combinatorics of clusters. Lectures 1-2 cover classical material: root systems, finite reflection groups, and the Cartan-Killing classification. Lectures 3-4 provide an introduction to cluster algebras from a combinatorial perspective. Lecture 5 is devoted to related topics in enumerative combinatorics.

  14. Cluster beam sources. Part 1. Methods of cluster beams generation

    Directory of Open Access Journals (Sweden)

    A.Ju. Karpenko

    2012-10-01

    Full Text Available The short review on cluster beams generation is proposed. The basic types of cluster sources are considered and the processes leading to cluster formation are analyzed. The parameters, that affects the work of cluster sources are presented.

  15. Cluster beam sources. Part 1. Methods of cluster beams generation

    OpenAIRE

    A.Ju. Karpenko; V.A. Baturin

    2012-01-01

    The short review on cluster beams generation is proposed. The basic types of cluster sources are considered and the processes leading to cluster formation are analyzed. The parameters, that affects the work of cluster sources are presented.

  16. Cancer Clusters

    Science.gov (United States)

    ... of cancer. Cancer clusters can help scientists identify cancer-causing substances in the environment. For example, in the early 1970s, a cluster ... the area and time period over which the cancers were diagnosed. They also ask about specific environmental hazards or concerns in the affected area. If ...

  17. PATTERN OF ROOTING AND GROWTH OF CUTTINGS OF SOME SPECIES OF INSECTICIDAL AND MEDICINAL IMPORTANCE AS AFFECTED BY GROWTH PROMOTING SUBSTANCES

    Directory of Open Access Journals (Sweden)

    Obi, E.A

    2013-06-01

    Full Text Available This study was designed to examine the effects of promoting substances on bud retention, rooting and plantlets survival of rooted cuttings on selected tree species using growth promoting substances. Stem cuttings were treated with rooting-promoting substances, planted in plastic pots filled with top soil and arranged using a completely randomized design (CRD in a screen house. Stem cuttings of pepper fruit, guava, bush mango and cashew were obtained from the Teaching and Research Farm, Federal University of Technology, Akure, Nigeria. The experiments were conducted in 2010. The effects of growth promoting substances namely indole-3-butyric acid (IBA, indole-3-acetic acid (IAA and 1-naphthalene acetic acid (NAA applied 50 µM concentration and coconut water (50% dilution were evaluated on adventitious root formation, shoot growth (bud retention and survival of plantlets of hard- to semi-hardwood cuttings of tested tree species. The effects of growth promoting substances were significant on emergence of plantlets (rooting, growth and survival of plantlets. Number of sprouts (plantlets produced were highest in guava and pepper fruit followed by bush mango and cashew. The cuttings from guava and pepper fruit treated with coconut water and NAA promoted the survival of plantlets. Coconut water and NAA were found better than IBA and IAA in terms of bud retention and rooting, leaf development and survival of plantlets. In most of the tested species, wilting of leaves commenced 6 weeks after planting (WAP and attained 100% mortality thereafter except for pepper fruit cuttings dipped in coconut water. The treatments modified the rooting response among species by promoting percentages of rooting, reduction in bud abscission and plantlet survival. The results affirmed the possibility of propagating plantlets from stem cuttings of the tested species using growth promoting substances.

  18. Arabidopsis thaliana AtUTr7 Encodes a Golgi-Localized UDP-Glucose/UDP-Galactose Transporter that Affects Lateral Root Emergence

    Institute of Scientific and Technical Information of China (English)

    Michael Handford; Cecilia Rodríguez-Furlán; Lorena Marchant; Marcelo Segura; Daniela Gómez; Elena Alvarez-Buyll; Guang-Yan Xiong; Markus Pauly; Ariel Orellana

    2012-01-01

    Nucleotide sugar transporters (NSTs) are antiporters comprising a gene family that plays a fundamental role in the biosynthesis of complex cell wall polysaccharides and glycoproteins in plants.However,due to the limited number of related mutants that have observable phenotypes,the biological function(s) of most NSTs in cell wall biosynthesis and assembly have remained elusive.Here,we report the characterization of AtUTr7 from Arabidopsis (Arabidopsis thaliana (L.) Heynh.),which is homologous to multi-specific UDP-sugar transporters from Drosophila melanogaster,humans,and Caenorhabditis elegans.We show that AtUTr7 possesses the common structural characteristics conserved among NSTs.Using a green fluorescent protein (GFP) tagged version,we demonstrate that AtUTr7 is localized in the Golgi apparatus.We also show that AtUTr7 is widely expressed,especially in the roots and in specific floral organs.Additionally,the results of an in vitro nucleotide sugar transport assay carried out with a tobacco and a yeast expression system suggest that AtUTr7 is capable of transferring UDP-Gal and UDP-GIc,but not a range of other UDP-and GDP-sugars,into the Golgi lumen.Mutants lacking expression of AtUTr7 exhibited an early proliferation of lateral roots as well as distorted root hairs when cultivated at high sucrose concentrations.Furthermore,the distribution of homogalacturonan with a low degree of methyl esterification differed in lateral root tips of the mutant compared to wild-type plants,although additional analytical procedures revealed no further differences in the composition of the root cell walls.This evidence suggests that the transport of UDP-Gal and UDP-GIc into the Golgi under conditions of high root biomass production plays a role in lateral root and root hair development.

  19. Arabidopsis phosphatidylinositol monophosphate 5-kinase 2 is involved in root gravitropism through regulation of polar auxin transport by affecting the cycling of PIN proteins

    Institute of Scientific and Technical Information of China (English)

    Yu Mei; Wen-Jing Jia; Yu-Jia Chu; Hong-Wei Xue

    2012-01-01

    Phosphatidylinositol monophosphate 5-kinase(PIP5K)catalyzes the synthesis of PI-4,5-bisphosphate(PtdIns(4,5)P2)by phosphorylation of PI-4-phosphate at the 5 position of the inositol ring,and is involved in regulating multiple developmental processes and stress responses.We here report on the functional characterization of Arabidopsis PIP5K2,which is expressed during lateral root initiation and elongation,and whose expression is enhanced by exogenous auxin.The knockout mutant pip5k2 shows reduced lateral root formation,which could be recovered with exogenous auxin,and interestingly,delayed root gravity response that could not be recovered with exogenous auxin.Crossing with the DR5-GUS marker line and measurement of free IAA content confirmed the reduced auxin accumulation in pip5k2.In addition,analysis using the membrane-selective dye FM4-64 revealed the decelerated vesicle trafficking caused by PtdIns(4,5)P2 reduction,which hence results in suppressed cycling of PIN proteins(PIN2 and 3),and delayed redistribution of PIN2 and auxin under gravistimulation in pipSk2 roots.On the contrary,PtdIns(4,5)P2 significantly enhanced the vesicle trafficking and cycling of PIN proteins.These results demonstrate that PIP5K2 is involved in regulating lateral root formation and root gravity response,and reveal a critical role of PIP5K2/Ptdlns(4,5)P2 in root development through regulation of PIN proteins,providing direct evidence of crosstalk between the phosphatidylinositol signaling pathway and auxin response,and new insights into the control of polar auxin transport.

  20. Arabidopsis phosphatidylinositol monophosphate 5-kinase 2 is involved in root gravitropism through regulation of polar auxin transport by affecting the cycling of PIN proteins.

    Science.gov (United States)

    Mei, Yu; Jia, Wen-Jing; Chu, Yu-Jia; Xue, Hong-Wei

    2012-03-01

    Phosphatidylinositol monophosphate 5-kinase (PIP5K) catalyzes the synthesis of PI-4,5-bisphosphate (PtdIns(4,5)P(2)) by phosphorylation of PI-4-phosphate at the 5 position of the inositol ring, and is involved in regulating multiple developmental processes and stress responses. We here report on the functional characterization of Arabidopsis PIP5K2, which is expressed during lateral root initiation and elongation, and whose expression is enhanced by exogenous auxin. The knockout mutant pip5k2 shows reduced lateral root formation, which could be recovered with exogenous auxin, and interestingly, delayed root gravity response that could not be recovered with exogenous auxin. Crossing with the DR5-GUS marker line and measurement of free IAA content confirmed the reduced auxin accumulation in pip5k2. In addition, analysis using the membrane-selective dye FM4-64 revealed the decelerated vesicle trafficking caused by PtdIns(4,5)P(2) reduction, which hence results in suppressed cycling of PIN proteins (PIN2 and 3), and delayed redistribution of PIN2 and auxin under gravistimulation in pip5k2 roots. On the contrary, PtdIns(4,5)P(2) significantly enhanced the vesicle trafficking and cycling of PIN proteins. These results demonstrate that PIP5K2 is involved in regulating lateral root formation and root gravity response, and reveal a critical role of PIP5K2/PtdIns(4,5)P(2) in root development through regulation of PIN proteins, providing direct evidence of crosstalk between the phosphatidylinositol signaling pathway and auxin response, and new insights into the control of polar auxin transport. PMID:21894193

  1. Root fractures

    DEFF Research Database (Denmark)

    Andreasen, Jens Ove; Christensen, Søren Steno Ahrensburg; Tsilingaridis, Georgios

    2012-01-01

    The purpose of this study was to analyze tooth loss after root fractures and to assess the influence of the type of healing and the location of the root fracture. Furthermore, the actual cause of tooth loss was analyzed.......The purpose of this study was to analyze tooth loss after root fractures and to assess the influence of the type of healing and the location of the root fracture. Furthermore, the actual cause of tooth loss was analyzed....

  2. Square Root +

    Science.gov (United States)

    Frederiksen, John G.

    1969-01-01

    A rational presentation of the so-called long division method for extracting the square root of a number. Diagrams are used to show relationship of this technique to the binomial theorem. Presentation exposes student to many facets of mathematics in addition to the mechanics of funding square root and cube root. Geometry, algebraic statements,…

  3. Evaluation of a Classroom-Based Psychosocial Intervention in Conflict-Affected Nepal: A Cluster Randomized Controlled Trial

    Science.gov (United States)

    Jordans, Mark J. D.; Komproe, Ivan H.; Tol, Wietse A.; Kohrt, Brandon A.; Luitel, Nagendra P.; Macy, Robert D.; de Jong, Joop T. V. M.

    2010-01-01

    Background: In situations of ongoing violence, childhood psychosocial and mental health problems require care. However, resources and evidence for adequate interventions are scarce for children in low- and middle-income countries. This study evaluated a school-based psychosocial intervention in conflict-affected, rural Nepal. Methods: A cluster…

  4. Ca2+- and Mg2+-ATPase activities in winter wheat root plasma membranes as affected by NaCl stress during growth

    NARCIS (Netherlands)

    Mansour, MMF; van Hasselt, PR; Kuiper, PJC

    1998-01-01

    Winter wheat seedlings were grown in Hoagland nutrient solution with or without 100 mmol/L NaCl added. Plasma membranes from root cells were prepared by aqueous polymer two phase partitioning and the stimulation of plasma membrane ATPase activity by Mg2+ and Ca2+ was investigated. The enzyme was act

  5. Sulfate and thiol levels in roots and shoot of sulfur-deprived spinach plants as affected by high pedospheric sulfate levels

    NARCIS (Netherlands)

    Poortinga, AM; de Kok, LJ

    2000-01-01

    Sulfur-deprivation of spinach resulted in a reduced growth, a decreased shoot/root ratio and an increase in dry matter content. The content of sulfur, thiols and soluble proteins was strongly decreased, whereas that of nitrate and free amino acids was increased. When sulfur-deprived plants were tran

  6. In vitro development and improvement of chromium (vi)-affected adventitious roots of solanum tuberosum l. with ga/sub 3/ and iaa application

    International Nuclear Information System (INIS)

    This study was undertaken In vitro to investigate the inhibitory effects of Chromium (Cr) VI by using K/sub 2/Cr/sub 2/O/sub 7/ on the growth of adventitious roots of potato (Solanum tuberosum L. cv Desiree). Another objective was to determine possible reversal of the detrimental growth effects with suitable combinations of GA/sub 3/ and IAA. It was observed that the applied Cr VI (100 ppm) alone in MS media inhibited root growth. However, addition of selected combinations of GA/sub 3/ and IAA in the MS media along with Cr VI improved the root growth. The plants grown on MS medium + 100 ppm K/sub 2/Cr/sub 2/O/sub 7/ resulted in reduction in number of adventitious roots up to 36.26%, number of rootlets (80.64%), diameter (37.27%), fresh and dry weights (72.96 and 84.74%, respectively) in comparison with control (MS medium). MS media containing 100 ppm K/sub 2/Cr/sub 2/O/sub 7/ + 20 ppm GA/sub 3/ + 16 ppm IAA enhanced the average number of roots from 4.78 to 62.6, number of rootlets from 2.6 to 28.2, diameter from 0.13 mm to 0.68 mm, fresh weight from 34.4 mg to 1234.75 mg and dry weight from 1.8 mg to 80.40 mg compared with cultures grown on MS + 100 ppm Cr (VI). The results thus highlight the fact that the deleterious effects of Cr VI on potato growth In vitro can be reversed with suitable hormonal treatments. Furthermore, this research has possible implications on large scale potato cultivation under heavy metal stress in a broader sense. (author)

  7. Factors affecting induction of shoot cluster of Artemisia annua%青蒿丛生芽诱导影响因素的研究

    Institute of Scientific and Technical Information of China (English)

    耿飒; 姬生栋; 袁金云; 卢龙斗; 叶和春; 李国凤

    2004-01-01

    目的对影响青蒿丛生芽诱导因素进行基础性研究.方法把常规的植物组织培养技术应用于调控青蒿中次生代谢产物青蒿素的生物合成代谢.结果青蒿的基因型,激素和基本培养基对丛生芽的发生有显著影响,而光强在1000~6000lx和温度在20℃~30℃对丛生芽的发生影响不大;在5种基因型的青蒿中,025丛生芽的诱导率最高;诱导丛生芽的激素组合是6-BA 2.0mg/L和NAA 0.15mg/L;另外,离子在青蒿丛生芽的诱导和青蒿素的生物合成过程中起着非常重要的作用.结论组织培养条件下,青蒿丛生芽的诱导及青蒿素的生物合成可以通过理化因子有效地进行调控.%Object To study the factors affecting the induction of shoot cluster of Artemisia annua.Methods Conventional plant tissue culture technology was applied to regulate the biosynthetic metabolism of secondary metabolism product,artemisinin of A.annua.Results Effects of genotype,hormones,basal medium on the induction of A.annua shoot cluster were notable,while that of light intensity ranging between 1000-6000 lx and temperature ranging between 20 ℃-30 ℃ were not.Among the five A.annua strains used,the induction ratio of strain 025 was the best.The optimal concentration for induction of shoot cluster was 6-BA 2.0 mg/L and NAA 0.15 mg/L.Ions were also found to be very important in the shoot cluster induction and the biosynthesis of artemisnin.Conclusion Effective regulation of induction of A.annua shoot cluster and artemisinin biosynthesis can be carried out via the regulation of physical and chemical factors.

  8. Cluster algebras of infinite rank as colimits

    OpenAIRE

    Gratz, Sira

    2014-01-01

    We formalize the way in which one can think about cluster algebras of infinite rank by showing that every rooted cluster algebra of infinite rank can be written as a colimit of rooted cluster algebras of finite rank. Relying on the proof of the posivity conjecture for skew-symmetric cluster algebras (of finite rank) by Lee and Schiffler, it follows as a direct consequence that the positivity conjecture holds for cluster algebras of infinite rank. Furthermore, we give a sufficient and necessar...

  9. Ectopic expression of R3 MYB transcription factor gene OsTCL1 in Arabidopsis, but not rice, affects trichome and root hair formation

    Science.gov (United States)

    Zheng, Kaijie; Tian, Hainan; Hu, Qingnan; Guo, Hongyan; Yang, Li; Cai, Ling; Wang, Xutong; Liu, Bao; Wang, Shucai

    2016-01-01

    In Arabidopsis, a MYB-bHLH-WD40 (MBW) transcriptional activator complex activates the homeodomain protein gene GLABRA2 (GL2), leading to the promotion of trichome formation and inhibition of root hair formation. The same MBW complex also activates single-repeat R3 MYB genes. R3 MYBs in turn, play a negative feedback role by competing with R2R3 MYB proteins for binding bHLH proteins, thus blocking the formation of the MBW complex. By BLASTing the rice (Oryza sativa) protein database using the entire amino acid sequence of Arabidopsis R3 MYB transcription factor TRICHOMELESS1 (TCL1), we found that there are two genes in rice genome encoding R3 MYB transcription factors, namely Oryza sativa TRICHOMELESS1 (OsTCL1) and OsTCL2. Expressing OsTCL1 in Arabidopsis inhibited trichome formation and promoted root hair formation, and OsTCL1 interacted with GL3 when tested in Arabidopsis protoplasts. Consistent with these observations, expression levels of GL2, R2R3 MYB transcription factor gene GLABRA1 (GL1) and several R3 MYB genes were greatly reduced, indicating that OsTCL1 is functional R3 MYB. However, trichome and root hair formation in transgenic rice plants overexpressing OsTCL1 remained largely unchanged, and elevated expression of OsGL2 was observed in the transgenic rice plants, indicating that rice may use different mechanisms to regulate trichome formation. PMID:26758286

  10. Roots & Hollers

    OpenAIRE

    Kollman, Patrick L; Gorman, Thomas A.

    2011-01-01

    Roots & Hollers, 2011 A documentary by Thomas Gorman & Patrick Kollman Master’s Project Abstract: Roots & Hollers uncovers the wild American ginseng trade, revealing a unique intersection between Asia and rural America. Legendary in Asia for its healing powers, ginseng helps sustain the livelihoods of thousands in Appalachia. A single root can sell for thousands of dollars at auction. Shot on-location in the mountains of Kentucky and West Virginia, this student doc...

  11. Arabidopsis phosphatidylinositol monophosphate 5-kinase 2 is involved in root gravitropism through regulation of polar auxin transport by affecting the cycling of PIN proteins

    OpenAIRE

    Mei, Yu; Jia, Wen-Jing; Chu, Yu-Jia; Xue, Hong-Wei

    2011-01-01

    Phosphatidylinositol monophosphate 5-kinase (PIP5K) catalyzes the synthesis of PI-4,5-bisphosphate (PtdIns(4,5)P2) by phosphorylation of PI-4-phosphate at the 5 position of the inositol ring, and is involved in regulating multiple developmental processes and stress responses. We here report on the functional characterization of Arabidopsis PIP5K2, which is expressed during lateral root initiation and elongation, and whose expression is enhanced by exogenous auxin. The knockout mutant pip5k...

  12. Growth temperature affects sensory quality and contents of glucosinolates, vitamin C and sugars in swede roots (Brassica napus L. ssp. rapifera Metzg.).

    Science.gov (United States)

    Johansen, Tor J; Hagen, Sidsel F; Bengtsson, Gunnar B; Mølmann, Jørgen A B

    2016-04-01

    Swede is a root vegetable grown under a range of growth conditions that may influence the product quality. The objective of this controlled climate study was to find the effect of growth temperature on sensory quality and the contents of glucosinolates, vitamin C and soluble sugars. High temperature (21 °C) enhanced the intensities of sensory attributes like pungent odour, bitterness, astringency and fibrousness, while low temperature (9 °C) was associated with acidic odour, sweet taste, crispiness and juiciness. Ten glucosinolates were quantified, with progoitrin as the dominant component followed by glucoberteroin, both with highest content at 21 °C. Vitamin C also had its highest content at 21 °C, while the total sugar content was lowest at this temperature. In conclusion, the study demonstrated clear effects of growth temperature on sensory quality and some chemical properties of swede and indicated a good eating quality of swedes grown at low temperatures. PMID:26593487

  13. The community structure of endophytic bacteria in different parts of Huanglongbing-affected citrus plants

    Science.gov (United States)

    The analyses methods of Pearson correlation coefficient (PCC), hierarchical cluster analysis and diversity index were used to study the relevance between citrus huanglongbing (HLB) and the endophytic bacteria in different branches and leaves as well as roots of huanglongbing (HLB)-affected citrus tr...

  14. Ectopic expression of foxtail millet zip-like gene,SiPf40,in transgenic rice plants causes a pleiotropic phenotype affecting tillering,vascular distribution and root development

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Plant architecture determines grain production in rice(Oryza sativa) and is affected by important agronomic traits such as tillering,plant height,and panicle morphology.Many key genes involved in controlling the initiation and outgrowth of axillary buds,the elongation of stems,and the architecture of inflorescences have been isolated and analyzed.Previous studies have shown that SiPf40,which was identified from a foxtail millet(Setaria italica) immature seed cDNA library,causes extra branches and tillers in SiPf40-transgenic tobacco and foxtail millet,respectively.To reconfirm its function,we generated transgenic rice plants overexpressing SiPf40 under the control of the ubiquitin promoter.SiPf40-overexpressing transgenic plants have a greater tillering number and a wider tiller angle than wild-type plants.Their root architecture is modified by the promotion of lateral root development,and the distribution of xylem and phloem in the vascular bundle is affected.Analysis of hormone levels showed that the ratios of indole-3-acetic acid/zeatin(IAA/ZR) and IAA/gibberellic acid(IAA/GA) decreased in SiPf40-transgenic plants compared with wild-type plants.These findings strongly suggest that SiPf40 plays an important role in plant architecture.

  15. Root resorption

    DEFF Research Database (Denmark)

    Kjaer, Inger

    2014-01-01

    Introduction: This paper summarizes the different conditions, which have a well-known influence on the resorption of tooth roots, exemplified by trauma and orthodontic treatment. The concept of the paper is to summarize and explain symptoms and signs of importance for avoiding resorption during...... orthodontic treatment. The Hypothesis: The hypothesis in this paper is that three different tissue layers covering the root in the so-called periroot sheet can explain signs and symptoms of importance for avoiding root resorption during orthodontic treatment. These different tissue layers are; outermost......-an ectodermal tissue layer (Malassez′s epithelium), a middle layer-composed by the collagen-mesodermal tissue layer, and an innermost root-close innervation layer. Abnormalities in one of these tissue layers are thought to cause inflammatory processes in the periodontal membrane comparable to inflammatory...

  16. Keberhasilan sambungan pada beberapa jenis batang atas dan famili batang bawah kakao (Theobroma cocoa L.. (Grafting performance of some scion clones and root-stock family on cocoa (Theobroma cocoa L.

    Directory of Open Access Journals (Sweden)

    Indah Anita Sari

    2012-08-01

    Full Text Available Differences in performance of grafting seedling were estimated from effect of using the root-stock and scion clones. This research aimed to study the differences of performance of some root-stock and scion clones on grafting seedling. The study used split plot design. First factor was root-stock consisted of ICS 60, Sca 6, Sca 12 and KW 165 and the second factor were 12 scions clones consisted of ICCRI 01, ICCRI 04, ICCRI 05, DR 2, Sulawesi 1, Sulawesi 2, KW 516, KW 514, KW 617, KW 570, KEE 2, and KW 604. There were three replication in each treatment and each replication consisted of 15 samples. Viability, lingkage diameter, ratio of root-stock and scion, hight of shoot, number of leaves and shoot were observed. The study showed that differences of root-stock just affected viability, lingkage diameter, and high of shoot. Scion clones factor affected to all of the characters. Their interaction caused the differences of all characters except of the number of shoot. Root-stock Sca 6 showed the lowest viability and number of the shoot, however root-stock KW 165 and ICS 60 showed the best performance to all parameters. The cluster analysis was done based on growth parameters and viability on lingkage distance of 15. There were three clusters; cluster 1 (KW 570, cluster 2 (ICCRI 04, ICCRI 05, Sulawesi 1, Sulawesi 2, KW 514, KW 165 and cluster 3 (ICCRI 01, DR 2, KW 516, KW 617, KW 604. Correlation analysis showed that main factor which affected the high viability root-stock diameter and diameter ratio of root-stock and scion were used.

  17. Constitutive expression of pathogen-inducible OsWRKY31 enhances disease resistance and affects root growth and auxin response in transgenic rice plants

    Institute of Scientific and Technical Information of China (English)

    Juan Zhang; Youliang Peng; Zejian Guo

    2008-01-01

    WRKY transcription factors have many regulatory roles in response to biotic and abiotic stresses. In this study, we isolated a rice WRKY gene (OsWRKY31) that is induced by the rice blast fungus Magnaporthe grisea and auxin. This gene encodes a polypeptide of 211 amino-acid residues and belongs to a subgroup of the rice WRKY gene family that probably originated after the divergence of monocot and dicot plants. OsWRKY31 was found to be localized to the nucleus of onion epidermis cells to transiently express OsWRKY31-eGFP fusion protein. Analysis of 0sWRKY31 and its mutants fused with a Cal4 DNA-binding domain indicated that OsWRKY31 has transactivation activity in yeast. Overexpression of the OsWRKY31 gene was found to enhance resistance against infection with M. grisea, and the transgenic lines exhibited reduced lateral root formation and elongation compared with wild-type and RNAi plants. The lines with overexpression showed constitutive expression of many defense-related genes, such as PBZ1 and OsSci2, as well as early auxin-response genes, such as OsIAA4 and OsCrll genes. Furthermore, the plants with overexpression were less sensitive to exogenously supplied IBA, NAA and 2,4-D at high concentrations, suggesting that overexpression of the OsWRKY31 gene might alter the auxin response or transport. These results also suggest that OsWRKY31 might be a common component in the signal transduction pathways of the auxin response and the defense response in rice.

  18. Determination of the lipophilicity of Salvia miltiorrhiza Radix et Rhizoma (danshen root) ingredients by microemulsion liquid chromatography: optimization using cluster analysis and a linear solvation energy relationship-based method.

    Science.gov (United States)

    Li, Liangxing; Yang, Jianrui; Huang, Hongzhang; Xu, Liyuan; Gao, Chongkai; Li, Ning

    2016-07-01

    We evaluated 26 microemulsion liquid chromatography (MELC) systems for their potential as high-throughput screening platforms capable of modeling the partitioning behaviors of drug compounds in an n-octanol-water system, and for predicting the lipophilicity of those compounds (i.e. logP values). The MELC systems were compared by cluster analysis and a linear solvation energy relationship (LSER)-based method, and the optimal system was identified by comparing their Euclidean distances with the LSER coefficients. The most effective MELC system had a mobile phase consisting of 6.0% (w/w) Brij35 (a detergent), 6.6% (w/w) butanol, 0.8% (w/w) cyclohexane, 86.6% (w/w) buffer solution and 8 mm cetyltrimethyl ammonium bromide. The reliability of the established platform was confirmed by the agreement between the experimental data and the predicted values. The logP values of the ingredients of danshen root (Salvia miltiorrhiza Radix et Rhizoma) were then predicted. Copyright © 2015 John Wiley & Sons, Ltd. PMID:26490541

  19. Automated Root Tracking with "Root System Analyzer"

    Science.gov (United States)

    Schnepf, Andrea; Jin, Meina; Ockert, Charlotte; Bol, Roland; Leitner, Daniel

    2015-04-01

    Crucial factors for plant development are water and nutrient availability in soils. Thus, root architecture is a main aspect of plant productivity and needs to be accurately considered when describing root processes. Images of root architecture contain a huge amount of information, and image analysis helps to recover parameters describing certain root architectural and morphological traits. The majority of imaging systems for root systems are designed for two-dimensional images, such as RootReader2, GiA Roots, SmartRoot, EZ-Rhizo, and Growscreen, but most of them are semi-automated and involve mouse-clicks in each root by the user. "Root System Analyzer" is a new, fully automated approach for recovering root architectural parameters from two-dimensional images of root systems. Individual roots can still be corrected manually in a user interface if required. The algorithm starts with a sequence of segmented two-dimensional images showing the dynamic development of a root system. For each image, morphological operators are used for skeletonization. Based on this, a graph representation of the root system is created. A dynamic root architecture model helps to determine which edges of the graph belong to an individual root. The algorithm elongates each root at the root tip and simulates growth confined within the already existing graph representation. The increment of root elongation is calculated assuming constant growth. For each root, the algorithm finds all possible paths and elongates the root in the direction of the optimal path. In this way, each edge of the graph is assigned to one or more coherent roots. Image sequences of root systems are handled in such a way that the previous image is used as a starting point for the current image. The algorithm is implemented in a set of Matlab m-files. Output of Root System Analyzer is a data structure that includes for each root an identification number, the branching order, the time of emergence, the parent

  20. Root canal

    Science.gov (United States)

    Endodontic therapy ... the root of a tooth. Generally, there is pain and swelling in the area. The infection can ... You may have some pain or soreness after the procedure. An over-the-counter anti-inflammatory drug, such as ibuprofen or naproxen, can help relieve ...

  1. Nutritional regulation of root development.

    Science.gov (United States)

    Ruiz Herrera, León Francisco; Shane, Michael W; López-Bucio, José

    2015-01-01

    Mineral nutrients such as nitrogen (N), phosphorus (P), and iron (Fe) are essential for plant growth, development, and reproduction. Adequate provision of nutrients via the root system impacts greatly on shoot biomass and plant productivity and is therefore of crucial importance for agriculture. Nutrients are taken up at the root surface in ionic form, which is mediated by specific transport proteins. Noteworthy, root tips are able to sense the local and internal concentrations of nutrients to adjust growth and developmental processes, and ultimately, to increase or decrease the exploratory capacity of the root system. Recently, important progress has been achieved in identifying the mechanisms of nutrient sensing in wild- and cultivated species, including Arabidopsis, bean, maize, rice, lupin as well as in members of the Proteaceae and Cyperaceae families, which develop highly sophisticated root clusters as adaptations to survive in soils with very low fertility. Major findings include identification of transporter proteins and transcription factors regulating nutrient sensing, miRNAs as mobile signals and peptides as repressors of lateral root development under heterogeneous nutrient supply. Understanding the roles played by N, P, and Fe in gene expression and biochemical characterization of proteins involved in root developmental responses to homogeneous or heterogeneous N and P sources has gained additional interest due to its potential for improving fertilizer acquisition efficiency in crops. PMID:25760021

  2. Morfologia radicular e suprimento de potássio às raízes de milheto de acordo com a disponibilidade de água e potássio Root morphology and potassium supply to pearl millet roots as affected by soil water and potassium contents

    Directory of Open Access Journals (Sweden)

    C. A. Rosolem

    2003-10-01

    Full Text Available O milheto (Pennisetum glaucum é cultivado em épocas com deficiência hídrica, o que pode afetar a absorção de K. Este trabalho visou quantificar a importância de potenciais de água do solo (-0,03; -0,05; -0,10 e -0,50 MPa, associados a doses de potássio (15 e 120 mg dm-3 de K na morfologia radicular e nos processos de transporte de K às raízes de milheto. O experimento foi realizado em Botucatu (SP, em casa de vegetação. O milheto foi cultivado até 28 dias após a emergência, quando foram avaliados a fitomassa produzida e os teores de K, assim como a morfologia radicular. Foi estimada a contribuição do fluxo de massa e da difusão para o transporte de K no solo. Independentemente da dose de potássio e do teor de água no solo, a difusão foi o principal mecanismo de transporte de K até as raízes do milheto. Houve maior contribuição relativa do fluxo de massa, que correspondeu a 12 % do absorvido, na menor dose de potássio, contra 4 % na maior dose. Não houve efeito da disponibilidade hídrica nos mecanismos de transporte de K até as raízes do milheto.Pearl millet is usually grown in periods when water is deficient in soil; a fact that possibly affects the K uptake. The experiment in Botucatu, São Paulo State, Brazil, was conducted to evaluate the effects of soil water content (-0.03;-0.05;-0.10 and -0.50 MPa associated with K rates (15 and 120 mg dm-3 of K on the K mass flow and diffusion to pearl millet (Pennisetum glaucum (L. Leek roots in greenhouse conditions. In pots with soil from the arable layer of a Red Latosol, pearl millet was grown for 28 days after plant emergence, when the plants were harvested and the shoot and root dry matter, K contents, as well as the root morphology determined. K mass flow and diffusion to roots were estimated. Irrespective of soil K level and water content, diffusion was the main mechanism of K supply to the roots. There was a larger relative contribution of mass flow at the K lowest

  3. Cluster automorphism groups of cluster algebras of finite type

    OpenAIRE

    Chang, Wen; Zhu, Bin

    2015-01-01

    We study the cluster automorphism group $Aut(\\mathcal{A})$ of a coefficient free cluster algebra $\\mathcal{A}$ of finite type. A cluster automorphism of $\\mathcal{A}$ is a permutation of the cluster variable set $\\mathscr{X}$ that is compatible with cluster mutations. We show that, on the one hand, by the well-known correspondence between $\\mathscr{X}$ and the almost positive root system $\\Phi_{\\geq -1}$ of the corresponding Dynkin type, the piecewise-linear transformations $\\tau_+$ and $\\tau...

  4. A statistical approach to root system classification.

    Directory of Open Access Journals (Sweden)

    Gernot eBodner

    2013-08-01

    Full Text Available Plant root systems have a key role in ecology and agronomy. In spite of fast increase in root studies, still there is no classification that allows distinguishing among distinctive characteristics within the diversity of rooting strategies. Our hypothesis is that a multivariate approach for plant functional type identification in ecology can be applied to the classification of root systems. We demonstrate that combining principal component and cluster analysis yields a meaningful classification of rooting types based on morphological traits. The classification method presented is based on a data-defined statistical procedure without a priori decision on the classifiers. Biplot inspection is used to determine key traits and to ensure stability in cluster based grouping. The classification method is exemplified with simulated root architectures and morphological field data. Simulated root architectures showed that morphological attributes with spatial distribution parameters capture most distinctive features within root system diversity. While developmental type (tap vs. shoot-borne systems is a strong, but coarse classifier, topological traits provide the most detailed differentiation among distinctive groups. Adequacy of commonly available morphologic traits for classification is supported by field data. Three rooting types emerged from measured data, distinguished by diameter/weight, density and spatial distribution respectively. Similarity of root systems within distinctive groups was the joint result of phylogenetic relation and environmental as well as human selection pressure. We concluded that the data-define classification is appropriate for integration of knowledge obtained with different root measurement methods and at various scales. Currently root morphology is the most promising basis for classification due to widely used common measurement protocols. To capture details of root diversity efforts in architectural measurement

  5. Locally Finite Root Supersystems

    OpenAIRE

    YOUSOFZADEH, Malihe

    2013-01-01

    We introduce the notion of locally finite root supersystems as a generalization of both locally finite root systems and generalized root systems. We classify irreducible locally finite root supersystems.

  6. Cold temperature delays wound healing in postharvest sugarbeet roots

    Science.gov (United States)

    Storage temperature affects the rate and extent of wound-healing in a number of root and tuber crops. The effect of storage temperature on wound-healing in sugarbeet (Beta vulgaris L.) roots, however, is largely unknown. Wound-healing of sugarbeet roots was investigated using surface-abraded roots s...

  7. New theories of root growth modelling

    Science.gov (United States)

    Landl, Magdalena; Schnepf, Andrea; Vanderborght, Jan; Huber, Katrin; Javaux, Mathieu; Bengough, A. Glyn; Vereecken, Harry

    2016-04-01

    In dynamic root architecture models, root growth is represented by moving root tips whose line trajectory results in the creation of new root segments. Typically, the direction of root growth is calculated as the vector sum of various direction-affecting components. However, in our simulations this did not reproduce experimental observations of root growth in structured soil. We therefore developed a new approach to predict the root growth direction. In this approach we distinguish between, firstly, driving forces for root growth, i.e. the force exerted by the root which points in the direction of the previous root segment and gravitropism, and, secondly, the soil mechanical resistance to root growth or penetration resistance. The latter can be anisotropic, i.e. depending on the direction of growth, which leads to a difference between the direction of the driving force and the direction of the root tip movement. Anisotropy of penetration resistance can be caused either by microscale differences in soil structure or by macroscale features, including macropores. Anisotropy at the microscale is neglected in our model. To allow for this, we include a normally distributed random deflection angle α to the force which points in the direction of the previous root segment with zero mean and a standard deviation σ. The standard deviation σ is scaled, so that the deflection from the original root tip location does not depend on the spatial resolution of the root system model. Similarly to the water flow equation, the direction of the root tip movement corresponds to the water flux vector while the driving forces are related to the water potential gradient. The analogue of the hydraulic conductivity tensor is the root penetrability tensor. It is determined by the inverse of soil penetration resistance and describes the ease with which a root can penetrate the soil. By adapting the three dimensional soil and root water uptake model R-SWMS (Javaux et al., 2008) in this way

  8. CRESCIMENTO RADICULAR E NUTRIÇÃO DA CEVADA EM FUNÇÃO DA CALAGEM E APLICAÇÃO DE GESSO BARLEY NUTRITION AND ROOT GROWTH AS AFFECTED BY LIME AND GYPSUM APPLICATIONS

    Directory of Open Access Journals (Sweden)

    EDUARDO FÁVERO CAIRES

    2001-01-01

    growth can be affected by chemical modifications in the soil profile due to lime and gypsum applications. A field trial was carried out on a dystrophic Clay Rhodic Hapludox at Ponta Grossa, State of Paraná, Brazil, aiming at evaluating lime and gypsum effects on root growth and plant chemical traits of barley, cv. BR 2 (Al susceptible. A randomized complete block design was used, with three replications, in a split-plot layout. The main plots received dolomitic limestone treatments (no lime and 4.5 t.ha-1 of lime-on the surface or incorporated into the soil and the subplots, the rates of gypsum (0, 3, 6 and 9 t.ha-1, applied in the installation of a no-tillage system, in 1998. Barley was grown during the 1999 winter season, after the soybean crop. Liming (whether surface applied or incorporated into the soil, and gypsum rates did not significantly affected barley root growth, although gypsum provided better root relative distribution in the soil profile, mainly when associated to liming. Under severe water stress conditions there was no limitation to barley root growth in depth (for 6 mmol c.dm-3 exchangeable Ca and 35% Al saturation. Lime incorporation improved the plant nutrition as to N and K, but liming treatments did not affect grain yields-these were limited by the prolonged water deficit during flowering stage. However, gypsum increased N, P, K, Ca and S plant levels, even under water stress conditions, with significant effects on grain yields, due to increases in the exchangeable Ca, Ca/Mg relationships and S-SO4(2- levels available in the soil.

  9. Cluster Automorphisms

    OpenAIRE

    Assem, Ibrahim; Schiffler, Ralf; Shramchenko, Vasilisa

    2010-01-01

    In this article, we introduce the notion of cluster automorphism of a given cluster algebra as a $\\ZZ$-automorphism of the cluster algebra that sends a cluster to another and commutes with mutations. We study the group of cluster automorphisms in detail for acyclic cluster algebras and cluster algebras from surfaces, and we compute this group explicitly for the Dynkin types and the Euclidean types.

  10. Afrokoko Roots

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Give us a little background information about Afrokoko Roots.How long have you been performing together?It's an international Afrobeat outfit that I founded in Beijing three years ago.I founded it in order to show Chinese people that Africa is beyond what they see and hear on TV.For the purpose of cultural exchange,I hope it can help the Chinese learn about African culture,music,fashion,history and much more.Our band features two dancers,two backup singers,two percussionists,four brass players,a keyboard player,a guitar player and a drummer- and me as the lead vocal,drummer and dancer,which makes for live performances that are equally exciting sonically as they are visually.We have been traveling around,and so far,we have toured and performed in many Chinese cities such as Dalian (Liaoning Province),Hohhot (Inner Mongolia Autonomous Region) and Haikou (Hainan Province).

  11. IAA transport in corn roots includes the root cap

    International Nuclear Information System (INIS)

    In earlier reports we concluded that auxin is the growth regulator that controls gravicurvature in roots and that the redistribution of auxin occurs within the root cap. Since other reports did not detect auxin in the root cap, we attempted to confirm the IAA does move through the cap. Agar blocks containing 3H-IAA were applied to the cut surface of 5 mm long apical segments of primary roots of corn (mo17xB73). After 30 to 120 min radioactivity (RA) of the cap and root tissue was determined. While segments suspended in water-saturated air accumulated very little RA in the cap, application of 0.5 μ1 of dist. water to the cap (=controls) increased RA of the cap dramatically. Application to the cap of 0.5 μ1 of sorbitol or the Ca2+ chelator EGTA reduced cap RA to 46% and 70% respectively compared to water, without affecting uptake. Control root segments gravireacted faster than non-treated or osmoticum or EGTA treated segments. The data indicate that both the degree of hydration and calcium control the amount of auxin moving through the cap

  12. Haplotypes in the APOA1-C3-A4-A5 gene cluster affect plasma lipids in both humans and baboons

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Qian-fei; Liu, Xin; O' Connell, Jeff; Peng, Ze; Krauss, Ronald M.; Rainwater, David L.; VandeBerg, John L.; Rubin, Edward M.; Cheng, Jan-Fang; Pennacchio, Len A.

    2003-09-15

    Genetic studies in non-human primates serve as a potential strategy for identifying genomic intervals where polymorphisms impact upon human disease-related phenotypes. It remains unclear, however, whether independently arising polymorphisms in orthologous regions of non-human primates leads to similar variation in a quantitative trait found in both species. To explore this paradigm, we studied a baboon apolipoprotein gene cluster (APOA1/C3/A4/A5) for which the human gene orthologs have well established roles in influencing plasma HDL-cholesterol and triglyceride concentrations. Our extensive polymorphism analysis of this 68 kb gene cluster in 96 pedigreed baboons identified several haplotype blocks each with limited diversity, consistent with haplotype findings in humans. To determine whether baboons, like humans, also have particular haplotypes associated with lipid phenotypes, we genotyped 634 well characterized baboons using 16 haplotype tagging SNPs. Genetic analysis of single SNPs, as well as haplotypes, revealed an association of APOA5 and APOC3 variants with HDL cholesterol and triglyceride concentrations, respectively. Thus, independent variation in orthologous genomic intervals does associate with similar quantitative lipid traits in both species, supporting the possibility of uncovering human QTL genes in a highly controlled non-human primate model.

  13. Glucose and Auxin Signaling Interaction in Controlling Arabidopsis thaliana Seedlings Root Growth and Development

    OpenAIRE

    Mishra, Bhuwaneshwar S.; Manjul Singh; Priyanka Aggrawal; Ashverya Laxmi

    2009-01-01

    BACKGROUND: Plant root growth and development is highly plastic and can adapt to many environmental conditions. Sugar signaling has been shown to affect root growth and development by interacting with phytohormones such as gibberellins, cytokinin and abscisic acid. Auxin signaling and transport has been earlier shown to be controlling plant root length, number of lateral roots, root hair and root growth direction. PRINCIPAL FINDINGS: Increasing concentration of glucose not only controls root ...

  14. Programming with MPI on clusters

    International Nuclear Information System (INIS)

    The authors discuss the current state of development for the key aspects of MPI programming on clusters. These aspects are the evolution of the MPI Standard itself, developments in cluster hardware and system software that directly affect MPI implementations, and supporting software that facilitates the use of MPI on scalable clusters. In each case we give a brief background and summarize the current status

  15. Studies on the functions of different unit-roots and the grouping of roots in winter wheat

    International Nuclear Information System (INIS)

    The characteristics and functions of different unit-roots and their effects on the yield components in wheat were studied by means of 15N tracing technique. The root grouping was made by cluster analysis according to the function of different unit roots. The results were as follows: The unit-roots characters (weight, length etc.) and 15N absorption decreased progressively downward. 15N absorbed by any unit roots could be transported from root to tiller and from tiller to tiller, but the transporting ratio was different. According to the function, the wheat roots could be divided into 3 groups: primary root group, lower seconddary root group and upper secondary root group. The ratio of 15N absorption to the total N absorption in each group was 26.7%, 31.4% and 41.9% respectively. The differences among the three groups were that the primary root group functioned throughout whole life of wheat, mainly promoting tillers and increasing root numbers before winter; the lower secondary root group played the major role in strenthening tillers and promoting ear development; the upper secondary root group had the main function in determining the floret number, kernel number and kernel weight

  16. Comparative Transcriptomic Analysis of Salt Adaptation in Roots of Contrasting Medicago truncatula Genotypes

    Institute of Scientific and Technical Information of China (English)

    Ons Zahaf; Anouck Diet; Mounawer Badri; Ana Zabalza; Esther M.González; Hervé Delacroix; Véronique Gruber; Florian Frugier; Martin Crespi; Sandrine Blanchet; Axel de Zélicourt; Beno(i)t Alunni; Julie Plet; Carole Laffont; Laura de Lorenzo; Sandrine Imbeaud; Jean-Laurent Ichanté

    2012-01-01

    Evolutionary diversity can be driven by the interaction of plants with different environments.Molecular bases involved in ecological adaptations to abiotic constraints can be explored using genomic tools.Legumes are major crops worldwide and soil salinity is a main stress affecting yield in these plants.We analyzed in the Medicago truncatula legume the root transcriptome of two genotypes having contrasting responses to salt stress:TN1.11,sampled in a salty Tunisian soil,and the reference Jemalong A17 genotype.TN1.11 plants show increased root growth under salt stress as well as a differential accumulation of sodium ions when compared to A17.Transcriptomic analysis revealed specific gene clusters preferentially regulated by salt in root apices of TN1.11,notably those related to the auxin pathway and to changes in histone variant isoforms.Many genes encoding transcription factors (TFs) were also differentially regulated between the two genotypes in response to salt.Among those selected for functional studies,overexpression in roots of the A17 genotype of the bHLH-type TF most differentially regulated between genotypes improved significantly root growth under salt stress.Despite the global complexity of the differential transcriptional responses,we propose that an increase in this bHLH TF expression may be linked to the adaptation of M.truncatula to saline soil environments.

  17. Variations of fine root diameter with root order in Manchurian ash and Dahurian larch plantations

    Institute of Scientific and Technical Information of China (English)

    WANG Xiangrong; WANG Zhengquan; HAN Youzhi; GU Jiacun; GUO Dali; MEI Li

    2007-01-01

    Fine root lifespan and turnover play an important role in carbon allocation and nutrient cycling in forest ecosystems.Fine roots are typically defined as less than 1 or 2mm in diameter.However,when categorizing roots by this diameter size,the position of an individual root on the complex lateral branching pattern has often been ignored,and our knowledge about relationships between branching order and root function thus remains limited.More recently,studies on root survivals found that longevity was remarkably different in the same branching level due to diameter variations.The objectives of this study were:(1) To examine variations of fine root diameter from the first-to fifth-orders in Fraxinus mandshurica Rupr and Larix gmelinii Rupr roots;and (2) To reveal how the season,soil nutrient,and water availability affect root diameter in different branch order in two species.This study was conducted at Maoershan Forest Research Station (45°21'-45°25'N,127°30'-127°34'E) owned by Northeast Forestry University in Harbin,northeast China.Both F.mandshurica and L.gmelinii were planted in 1986.In each plantation,fine roots of two species by sampling up to five fine root branch orders three times during the 2003 growing season from two soil depths (i.e.,0-10 and 10-20 cm)were obtained.The results showed that average diameters of fine roots were significantly different among the five branch orders.The first-order had the thinner roots and the fifth order had the thickest roots,the diameter increasing regularly with the ascending branch orders in both species.If the diameter of fine roots was defined as being smaller than 0.5 mm,the first three orders ofF.mandshurica roots and the first two orders of L.gmelinii roots would be included in the fine root population.The diameter ranges of the fine roots from first-order to fifth-order were 0.15-0.58,0.18-0.70,0.26-1.05,0.36-1.43,and 0.71-2.96 mm for F.mandshurica,and 0.17-0.76,0.23-1.02,0.26-1.10,0.38-1.77,and 0.84-2.80 mm for L

  18. Unit roots, nonlinearities and structural breaks

    DEFF Research Database (Denmark)

    Haldrup, Niels; Kruse, Robinson; Teräsvirta, Timo;

    One of the most influential research fields in econometrics over the past decades concerns unit root testing in economic time series. In macro-economics much of the interest in the area originate from the fact that when unit roots are present, then shocks to the time series processes have a...... persistent effect with resulting policy implications. From a statistical perspective on the other hand, the presence of unit roots has dramatic implications for econometric model building, estimation, and inference in order to avoid the so-called spurious regression problem. The present paper provides a...... selective review of contributions to the field of unit root testing over the past three decades. We discuss the nature of stochastic and deterministic trend processes, including break processes, that are likely to affect unit root inference. A range of the most popular unit root tests are presented and...

  19. Root canal irrigants

    OpenAIRE

    Kandaswamy Deivanayagam; Venkateshbabu Nagendrababu

    2010-01-01

    Successful root canal therapy relies on the combination of proper instrumentation, irrigation, and obturation of the root canal. Of these three essential steps of root canal therapy, irrigation of the root canal is the most important determinant in the healing of the periapical tissues. The primary endodontic treatment goal must thus be to optimize root canal disinfection and to prevent reinfection. In this review of the literature, various irrigants and the interactions between irrigants are...

  20. Root discrimination of closely related crop and weed species using FT MIR-ATR spectroscopy

    Directory of Open Access Journals (Sweden)

    Catharina eMeinen

    2015-09-01

    Full Text Available Root discrimination of species is a pre-condition for studying belowground competition processes between crop and weed species. In this experiment, we tested Fourier transform mid-infrared (FT MIR-attenuated total reflection (ATR spectroscopy to discriminate roots of closely related crop and weed species grown in the greenhouse: maize/barnyard grass, barley/wild oat, wheat/blackgrass (Poaceae, and sugar beet/common lambsquarters (Chenopodiaceae. Fresh (moist and dried root segments as well as ground roots were analyzed by FT MIR-ATR spectroscopy. Root absorption spectra showed species specific peak distribution and peak height. A clear separation according to species was not possible with fresh root segments. Dried root segments (including root basis, middle section and root tip of maize/barnyard grass and sugar beet/common lambsquarters formed completely separated species clusters. Wheat and blackgrass separated in species specific clusters when root tips were removed from cluster analysis. A clear separation of dried root segments according to species was not possible in the case of barley and wild oat. Cluster analyses of ground roots revealed a 100 % separation of all tested crop and weed species combinations. Spectra grouped in Poaceae and Chenopodiaceae clusters. Within the Poaceae cluster, C3 and C4 species differed significantly in heterogeneity. Thus, root spectra reflected the degree of kinship. To quantify species proportion in root mixtures, a two- and a three-species model for species quantification in root mixtures of maize, barnyard grass, and wild oat was calculated. The models showed low standard errors of prediction (RMSEP and high residual predictive deviation (RPD values in an external test set validation. Hence, FT MIR-ATR spectroscopy seems to be a promising tool for root research even between closely related plant species.

  1. Differences in U root-to-shoot translocation between plant species explained by U distribution in roots

    Energy Technology Data Exchange (ETDEWEB)

    Straczek, Anne; Duquene, Lise [Belgium Nuclear Research Centre (SCK.CEN), Biosphere Impact Studies, Boeretang 200, 2400 Mol (Belgium); Wegrzynek, Dariusz [IAEA, Seibersdorf Laboratories, A-2444 Seibersdorf (Austria); Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, Al. Mickiewicza 30, 30-059 Krakow (Poland); Chinea-Cano, Ernesto [IAEA, Seibersdorf Laboratories, A-2444 Seibersdorf (Austria); Wannijn, Jean [Belgium Nuclear Research Centre (SCK.CEN), Biosphere Impact Studies, Boeretang 200, 2400 Mol (Belgium); Navez, Jacques [Royal Museum of Africa, Department of Geology, Leuvensesteenweg 13, 3080 Tervuren (Belgium); Vandenhove, Hildegarde, E-mail: hvandenh@sckcen.b [Belgium Nuclear Research Centre (SCK.CEN), Biosphere Impact Studies, Boeretang 200, 2400 Mol (Belgium)

    2010-03-15

    Accumulation and distribution of uranium in roots and shoots of four plants species differing in their cation exchange capacity of roots (CECR) was investigated. After exposure in hydroponics for seven days to 100 mumol U L{sup -1}, distribution of uranium in roots was investigated through chemical extraction of roots. Higher U concentrations were measured in roots of dicots which showed a higher CECR than monocot species. Chemical extractions indicated that uranium is mostly located in the apoplasm of roots of monocots but that it is predominantly located in the symplasm of roots of dicots. Translocation of U to shoot was not significantly affected by the CECR or distribution of U between symplasm and apoplasm. Distribution of uranium in roots was investigated through chemical extraction of roots for all species. Additionally, longitudinal and radial distribution of U in roots of maize and Indian mustard, respectively showing the lowest and the highest translocation, was studied following X-ray fluorescence (XRF) analysis of specific root sections. Chemical analysis and XRF analysis of roots of maize and Indian mustard clearly indicated a higher longitudinal and radial transport of uranium in roots of Indian mustard than in roots of maize, where uranium mostly accumulated in root tips. These results showed that even if CECR could partly explain U accumulation in roots, other mechanisms like radial and longitudinal transport are implied in the translocation of U to the shoot.

  2. Weighted Clustering

    DEFF Research Database (Denmark)

    Ackerman, Margareta; Ben-David, Shai; Branzei, Simina;

    2012-01-01

    We investigate a natural generalization of the classical clustering problem, considering clustering tasks in which different instances may have different weights.We conduct the first extensive theoretical analysis on the influence of weighted data on standard clustering algorithms in both the...... partitional and hierarchical settings, characterizing the conditions under which algorithms react to weights. Extending a recent framework for clustering algorithm selection, we propose intuitive properties that would allow users to choose between clustering algorithms in the weighted setting and classify...

  3. Cluster Headache

    OpenAIRE

    Frederick G Freitag

    1985-01-01

    Learning Objectives: Review the current understanding of the pathophysiology of cluster headache Be able to recognize the clinical features of cluster headache Be able to develop a strategy for treatment of cluster headache Cluster headache is divided into multiple subtypes under the IHC classification criteria. The vast majority of patients present with episodic cluster headache (3.1.1). This will be the focus of the presentation. The syndrome is characterized by repeated at...

  4. An Efficient Density based Improved K- Medoids Clustering algorithm

    OpenAIRE

    Raghuvira Pratap A; K Suvarna Vani; J Rama Devi; Dr.K Nageswara Rao

    2011-01-01

    Clustering is the process of classifying objects into different groups by partitioning sets of data into a series of subsets called clusters. Clustering has taken its roots from algorithms like k-medoids and k-medoids. However conventional k-medoids clustering algorithm suffers from many limitations. Firstly, it needs to have prior knowledge about the number of cluster parameter k. Secondly, it also initially needs to make random selection of k representative objects and if these initial k me...

  5. Genotypic recognition and spatial responses by rice roots

    OpenAIRE

    Fang, Suqin; Clark, Randy T.; Zheng, Ying; Iyer-Pascuzzi, Anjali S.; Weitz, Joshua S.; Kochian, Leon V.; Edelsbrunner, Herbert; Liao, Hong; Benfey, Philip N.

    2013-01-01

    Root system growth and development is highly plastic and is influenced by the surrounding environment. Roots frequently grow in heterogeneous environments that include interactions from neighboring plants and physical impediments in the rhizosphere. To investigate how planting density and physical objects affect root system growth, we grew rice in a transparent gel system in close proximity with another plant or a physical object. Root systems were imaged and reconstructed in three dimensions...

  6. Cluster headache attacks and multiple sclerosis

    OpenAIRE

    Gentile, Salvatore; Ferrero, Margherita; Vaula, Giovanna; Rainero, Innocenzo; Pinessi, Lorenzo

    2007-01-01

    We report the case of a patient who developed typical cluster headache attacks and was diagnosed as having multiple sclerosis (MS) at the same time. The headache attacks resolved after i.v. treatment with methylprednisolone. MR imaging showed a pontine demyelinating lesion involving the trigeminal nerve root inlet area, on the same side as the pain. The association between cluster headache and MS has been rarely described before. This case suggests that in patients with cluster headache neuro...

  7. Using Square Roots

    Science.gov (United States)

    Wilson, William Wynne

    1976-01-01

    This article describes techniques which enable the user of a comparatively simple calculator to perform calculations of cube roots, nth roots, trigonometric, and inverse trigonometric functions, logarithms, and exponentials. (DT)

  8. Cluster headache

    Science.gov (United States)

    Histamine headache; Headache - histamine; Migrainous neuralgia; Headache - cluster; Horton's headache ... Doctors do not know exactly what causes cluster headaches. They ... (chemical in the body released during an allergic response) or ...

  9. Isotopic clusters

    International Nuclear Information System (INIS)

    Spectra of isotopically mixed clusters (dimers of SF6) are calculated as well as transition frequencies. The result leads to speculations about the suitability of the laser-cluster fragmentation process for isotope separation. (Auth.)

  10. lAA and BAP affect protein phosphorylation-dependent processes during sucrose-mediated G1 to S and G2 to M transitions in root meristem cells of Vicia faba

    OpenAIRE

    Justyna Teresa Polit; Janusz Maszewski; Marzena Rosiak

    2011-01-01

    In carbohydrate-starved root meristems of Vicia faba subsp. minor, the expression of two Principal Control Points located at the final stages of the G1 (PCP1) and G2 (PCP2) phases has been found to be correlated with a marked decrease of protein phosphorylation within cell nuclei, nucleoli and cytoplasm. Adopting the same experimental model in our present studies, monoclonal FITC conjugated antibodies that recognize phosphorylated form of threonine (αTPab-FITC) were used to obtain an insight ...

  11. WHY ROOTING FAILS.

    Energy Technology Data Exchange (ETDEWEB)

    CREUTZ,M.

    2007-07-30

    I explore the origins of the unphysical predictions from rooted staggered fermion algorithms. Before rooting, the exact chiral symmetry of staggered fermions is a flavored symmetry among the four 'tastes.' The rooting procedure averages over tastes of different chiralities. This averaging forbids the appearance of the correct 't Hooft vertex for the target theory.

  12. Root canal irrigation

    NARCIS (Netherlands)

    L. van der Sluis; C. Boutsioukis; L.M. Jiang; R. Macedo; B. Verhaagen; M. Versluis

    2015-01-01

    The aims of root canal irrigation are the chemical dissolution or disruption and the mechanical detachment of pulp tissue, dentin debris and smear layer (instrumentation products), microorganisms (planktonic or biofilm), and their products from the root canal wall, their removal out of the root cana

  13. The Root Canal Biofilm

    NARCIS (Netherlands)

    Sluis, van der L.W.M.; Boutsioukis, C.; Jiang, L.M.; Macedo, R.; Verhaagen, B.; Versluis, M.; Chávez de Paz, E.; Sedgley, C.M.; Kishen, A.

    2015-01-01

    The aims of root canal irrigation are the chemical dissolution or disruption and the mechanical detachment of pulp tissue, dentin debris and smear layer (instrumentation products), microorganisms (planktonic or biofilm), and their products from the root canal wall, their removal out of the root cana

  14. Weighted Clustering

    OpenAIRE

    Ackerman, Margareta; Ben-David, Shai; Branzei, Simina; Loker, David

    2012-01-01

    We investigate a natural generalization of the classical clusteringproblem, considering clustering tasks in which differentinstances may have different weights.We conduct the firstextensive theoretical analysis on the influence of weighteddata on standard clustering algorithms in both the partitionaland hierarchical settings, characterizing the conditions underwhich algorithms react to weights. Extending a recent frameworkfor clustering algorithm selection, we propose intuitiveproperties that...

  15. Meaningful Clusters

    Energy Technology Data Exchange (ETDEWEB)

    Sanfilippo, Antonio P.; Calapristi, Augustin J.; Crow, Vernon L.; Hetzler, Elizabeth G.; Turner, Alan E.

    2004-05-26

    We present an approach to the disambiguation of cluster labels that capitalizes on the notion of semantic similarity to assign WordNet senses to cluster labels. The approach provides interesting insights on how document clustering can provide the basis for developing a novel approach to word sense disambiguation.

  16. Why Frequency Matters for Unit Root Testing

    OpenAIRE

    Boswijk, H.P.; Klaassen, F.J.G.M.

    2005-01-01

    It is generally believed that for the power of unit root tests, only the time span and not the observation frequency matters. In this paper we show that the observation frequency does matter when the high-frequency data display fat tails and volatility clustering, as is typically the case for financial time series such as exchange rate returns. Our claim builds on recent work on unit root and cointegration testing based non-Gaussian likelihood functions. The essential idea is that such method...

  17. Cluster Characteristics in a MIMO Indoor Propagation Environment

    DEFF Research Database (Denmark)

    Czink, Nicolai; Yin, Xuefeng; Ozcelik, Huseyin;

    2007-01-01

    , strong (obstructed-)line-of-sight clusters show Rician fading, corresponding to few dominant propagation paths, whereas most clusters exhibit Rayleigh fading, corresponding to many paths with approximately equal powers and uncorrelated phases. Root-mean-square cluster azimuth spreads (CASs) were...

  18. The Root Cap Determines Ethylene-Dependent Growth and Development in Maize Roots

    Institute of Scientific and Technical Information of China (English)

    Achim Hahn; Roman Zimmermann; Dierk Wanke; Klaus Harter; Hans G.Edelmann

    2008-01-01

    Besides providing protection against mechanical damage to the root tip,the root cap is involved in the perception and processing of diverse external and internal stimuli resulting in altered growth and development.The transduction of these stimuli includes hormonal signaling pathways such as those of auxin,ethylene and cytokinin.Here,we show that the root cap is essential for the ethylene-induced regulation of elongation growth and root hair formation in maize.Exogenously applied ethylene is no longer able to inhibit elongation growth when the root cap has been surgically removed prior to hormone treatment.Reconstitution of the cap positively correlates with the developing capacity of the roots to respond to ethylene again.In contrast,the removal of the root cap does not per se affect growth inhibition controlled by auxin and cytokinin.Furthermore,our semi-quantitative RT-PCR results support earlier findings that the maize root cap is a site of high gene expression activity with respect to sensing and responding to hormones such as ethylene.From these data,we propose a novel function of the root cap which is the establishment of competence to respond to ethylene in the distal zones of the root.

  19. Cluster Lenses

    CERN Document Server

    Kneib, Jean-Paul; 10.1007/s00159-011-0047-3

    2012-01-01

    Clusters of galaxies are the most recently assembled, massive, bound structures in the Universe. As predicted by General Relativity, given their masses, clusters strongly deform space-time in their vicinity. Clusters act as some of the most powerful gravitational lenses in the Universe. Light rays traversing through clusters from distant sources are hence deflected, and the resulting images of these distant objects therefore appear distorted and magnified. Lensing by clusters occurs in two regimes, each with unique observational signatures. The strong lensing regime is characterized by effects readily seen by eye, namely, the production of giant arcs, multiple-images, and arclets. The weak lensing regime is characterized by small deformations in the shapes of background galaxies only detectable statistically. Cluster lenses have been exploited successfully to address several important current questions in cosmology: (i) the study of the lens(es) - understanding cluster mass distributions and issues pertaining...

  20. Root-soil relationships and terroir

    Science.gov (United States)

    Tomasi, Diego

    2015-04-01

    Soil features, along with climate, are among the most important determinants of a succesful grape production in a certain area. Most of the studies, so far, investigated the above-ground vine response to differente edaphic and climate condition, but it is clearly not sufficient to explain the vine whole behaviour. In fact, roots represent an important part of the terroir system (soil-plant-atmosphere-man), and their study can provide better comprehension of vine responses to different environments. The root density and distribution, the ability of deep-rooting and regenerating new roots are good indicators of root well-being, and represents the basis for an efficient physiological activity of the root system. Root deepening and distribution are strongly dependent and sensitive on soil type and soil properties, while root density is affected mostly by canopy size, rootstock and water availability. According to root well-being, soil management strategies should alleviate soil impediments, improving aeration and microbial activity. Moreover, agronomic practices can impact root system performance and influence the above-ground growth. It is well known, for example, that the root system size is largely diminished by high planting densities. Close vine spacings stimulate a more effective utilization of the available soil, water and nutrients, but if the competition for available soil becomes too high, it can repress vine growth, and compromise vineyard longevity, productivity and reaction to growing season weather. Development of resilient rootstocks, more efficient in terms of water and nutrient uptake and capable of dealing with climate and soil extremes (drought, high salinity) are primary goals fore future research. The use of these rootstocks will benefit a more sustainable use of the soil resources and the preservation and valorisation of the terroir.

  1. Effect of localized nitrogen availability to soybean half-root systems on photosynthate partitioning to roots and nodules

    International Nuclear Information System (INIS)

    Soybean (Glycine max [L.] Merr. cv Davis) was grown in a split-root growth system designed to maintain control of the root atmosphere. Two experiments were conducted to examine how 80% Ar:20%, O2 (Ar:O2) and air (Air) atmospheres affected N assimilation (NH4NO3 and N2 fixation) and the partitioning of photosynthate to roots and nodules. Application of NH4NO3 to nonnodulated half-root systems enhanced root growth and root respiration at the site of application. A second experiment applied Ar:O2 or air to the two sides of nodulated soybean half-root systems for 11 days in the following combinations: (a) Air to both sides (Air/Air); (b) Air to one side, Ar:O2 to the other (Air/Ar:O2), and (c) Ar:O2 to both sides (Ar:O2/Ar:O2). Results indicated that dry matter and current photosynthate (14C) were selectively partitioned to nodules and roots where N2 was available. Both root and nodule growth on the Air side of Air/Ar:O2 plants was significantly greater than the Ar:O2 side. The relative partitioning of carbon and current photosynthate between roots and nodules on a half-root system was also affected by N2 availability. The Ar:O2 sides partitioned relatively more current photosynthate to roots (57%) than nodules (43%), while N2-fixing root systems partitioned 36 and 64% of the carbon to roots and nodules, respectively. The Ar:O2 atmosphere decreased root and nodule respiration by 80% and nitrogenase activity by 85% compared to half-root systems in Air while specific nitrogenase activity in Ar:O2 was 50% of nodules supplied Air. Results indicated that nitrogen assimilation, whether from N2 fixation or inorganic sources, had a localized effect on root development

  2. Role of calcium in gravity perception of plant roots

    Science.gov (United States)

    Evans, Michael L.

    Calcium ions may play a key role in linking graviperception by the root cap to the asymmetric growth which occurs in the elongation zone of gravistimulated roots. Application of calcium-chelating agents to the root cap inhibits gravitropic curvature without affecting growth. Asymmetric application of calcium to one side of the root cap induces curvature toward the calcium source, and gravistimulation induces polar movement of applied 45Ca2+ across the root cap toward the lower side. The action of calcium may be linked to auxin movement in roots since 1) auxin transport inhibitors interfere both with gravitropic curvature and gravi-induced polar calcium movement and 2) asymmetric application of calcium enhances auxin movement across the elongation zone of gravistimulated roots. Indirect evidence indicates that the calcium-modulated regulator protein, calmodulin, may be involved in either the transport or action of calcium in the gravitropic response mechanism of roots.

  3. lAA and BAP affect protein phosphorylation-dependent processes during sucrose-mediated G1 to S and G2 to M transitions in root meristem cells of Vicia faba

    Directory of Open Access Journals (Sweden)

    Justyna Teresa Polit

    2011-04-01

    Full Text Available In carbohydrate-starved root meristems of Vicia faba subsp. minor, the expression of two Principal Control Points located at the final stages of the G1 (PCP1 and G2 (PCP2 phases has been found to be correlated with a marked decrease of protein phosphorylation within cell nuclei, nucleoli and cytoplasm. Adopting the same experimental model in our present studies, monoclonal FITC conjugated antibodies that recognize phosphorylated form of threonine (αTPab-FITC were used to obtain an insight about how the indole-3-acetic acid (IAA, benzyl-6-aminopurine (BAP, and the mixture of both phytohormones influence the time-course changes in an overall protein phosphorylation during sucrose-mediated PCP1→S and PCP2→M transitions. Unsuspectedly, neither IAA, BAP, nor the mixture of both phytohormones supplied in combination with sucrose did up-regulate protein phosphorylation. However using the block-and-release method, it was shown that root meristems of Vicia provided with sucrose alone indicated higher levels of αTPab-FITC. Contrarily, phytohormones supplied in combination with sucrose induced apparent decline in phosphorylation of cell proteins, which - when compared with the influence of sucrose alone - became increasingly evident in time. Thus, it seems probable, that a general decline in the amount of αTPab-FITC labeled epitopes may overlay specific phosphorylations and dephosphorylations governed by the main cell cycle kinases and phosphatases.

  4. Data Clustering

    Science.gov (United States)

    Wagstaff, Kiri L.

    2012-03-01

    On obtaining a new data set, the researcher is immediately faced with the challenge of obtaining a high-level understanding from the observations. What does a typical item look like? What are the dominant trends? How many distinct groups are included in the data set, and how is each one characterized? Which observable values are common, and which rarely occur? Which items stand out as anomalies or outliers from the rest of the data? This challenge is exacerbated by the steady growth in data set size [11] as new instruments push into new frontiers of parameter space, via improvements in temporal, spatial, and spectral resolution, or by the desire to "fuse" observations from different modalities and instruments into a larger-picture understanding of the same underlying phenomenon. Data clustering algorithms provide a variety of solutions for this task. They can generate summaries, locate outliers, compress data, identify dense or sparse regions of feature space, and build data models. It is useful to note up front that "clusters" in this context refer to groups of items within some descriptive feature space, not (necessarily) to "galaxy clusters" which are dense regions in physical space. The goal of this chapter is to survey a variety of data clustering methods, with an eye toward their applicability to astronomical data analysis. In addition to improving the individual researcher’s understanding of a given data set, clustering has led directly to scientific advances, such as the discovery of new subclasses of stars [14] and gamma-ray bursts (GRBs) [38]. All clustering algorithms seek to identify groups within a data set that reflect some observed, quantifiable structure. Clustering is traditionally an unsupervised approach to data analysis, in the sense that it operates without any direct guidance about which items should be assigned to which clusters. There has been a recent trend in the clustering literature toward supporting semisupervised or constrained

  5. Genetic association among root morphology, root quality and root yield in ashwagandha (Withania somnifera)

    OpenAIRE

    Kumar Ramesh R.; Reddy Anjaneya Prasanna L.; Subbaiah Chinna J.; Kumar Niranjana A.; Prasad Nagendra H.N.; Bhukya Balakishan

    2011-01-01

    Ashwagandha (Withania somnifera) is a dryland medicinal crop and roots are used as valuable drug in traditional systems of medicine. Morphological variants (morphotypes) and the parental populations were evaluated for root - morphometric, quality and yield traits to study genetic association among them. Root morphometric traits (root length, root diameter, number of secondary roots/ plant) and crude fiber content exhibited strong association among them and ...

  6. Effects of acid deposition on tree roots

    Energy Technology Data Exchange (ETDEWEB)

    Persson, H. [Swedish Univ. of Agricultural Sciences (Sweden). Dept. of Ecology and Environmental Research

    1995-12-31

    Large forest regions in SW Sweden have been exposed to high levels of acid deposition for many decades, causing soil acidification in forest soils. Historically, SO{sub 2} has been the major acidification agent, but lately nitrogen compounds increasingly have become important. The amount and chemical form of nitrogen strongly affects the pH in the rhizosphere and rhizoplane. Many forest stands show a positive growth response to increased nitrogen input, even in heavily N-loaded areas. Nitrogen fertilization experiments suggest that part of the increased forest production is caused by a translocation of biomass production from below-ground to above-ground parts. At the same time fine-root growth dynamics are strongly affected by the high N supply. Deficiencies of various nutrients (Mg,Ca,K,Mn and Zn) obtained from needle analyses have been reported from different Picea abies stands. In areas with more extensive acidification and nutrient leaching, a decline in tree vitality has been observed. Although deficiency symptoms in forest trees may be reflected in nitrogen/cation ratios in fine roots, few attempts have been made to explain forest damage symptoms from fine-root chemistry. Root damage is often described as a decline in the amount of living fine roots, an increase in the amount of dead versus live fine roots (a lower live/dead ratio) and an increasing amount of dead medium and coarse roots. The primary objectives of the present presentation were to analyse available data on the effects of high nitrogen and sulphur deposition on mineral nutrient balance in tree fine roots and to evaluate the risk of Al interference with cation uptake by roots

  7. Cluster Chemistry

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    @@ Cansisting of eight scientists from the State Key Laboratory of Physical Chemistry of Solid Surfaces and Xiamen University, this creative research group is devoted to the research of cluster chemistry and creation of nanomaterials.After three-year hard work, the group scored a series of encouraging progresses in synthesis of clusters with special structures, including novel fullerenes, fullerene-like metal cluster compounds as well as other related nanomaterials, and their properties study.

  8. Factors affecting "in vitro" plant development and root colonization of sweet potato by Glomus etunicatum Becker & Gerd Fatores que afetam o desenvolvimento da planta e a colonização radicular "in vitro", da batata doce por Glomus etunicatum Becker & Gerd.

    Directory of Open Access Journals (Sweden)

    Wellington Bressan

    2002-01-01

    Full Text Available Nutrients media (Murashige & Skoog, Hoagland & Arnon and White's media supplemented or not with sucrose and substrates (vermiculite, agar and natrosol were tested for their effects on plant development and root colonization of micropropagated sweet potato, cv. White Star, by Glomus etunicatum Becker & Gerdemann (isolate INVAM FL S329. Addition of sucrose (3% did not affect plant development. However, hyphal growth and root colonization were depressed. Contrasting responses to media nutrient concentration were observed for plant height, root colonization, and hyphal growth. The highest concentration of nutrients in Murashige & Skoog medium improved plant development, but this medium decreased hypha growth and inhibited root colonization. Plants growing in vermiculite substrate had higher (p£0.05 development and mycorrhizal root colonization than those growing in agar or natrosol. The results indicate that colonization of micropropagated sweet potato by arbuscular mycorrhizal fungi is affected by media composition and type of substrate.Os meios de Murashige e Skoog, Hoagland, Arnon e White, suplementados ou não com sacorose, e tendo como substratos vermiculita, ágar ou natrosol foram utilizados para avaliar seus efeitos sobre o desenvolvimento da batata doce, c.v. White Star, e sua colonização por Glomus etunicatum Becker & Gerd. (isolado INVAM FL S329. A adição de sacorose (3% ao meio não afetou o desenvolvimento da planta, porém reduziu o crescimento das hifas de G. etunicatum e a colonização das raízes. A concentração de nutrientes dos meios utilizados mostrou efeitos contrastantes entre altura da planta, crescimento das hifas e colonização das raízes por G. etunicatum. A alta concentração de nutrientes no meio Murashige e Skoog estimulou o crescimento das plantas, reduziu o desenvolvimento das hifas e inibiu a colonização das raízes pelo fungo micorrízico. Plantas desenvolvidas em vermiculita mostraram maior

  9. Functional reorganization of human motor cortex after unaffected side C7 nerve root transposition

    International Nuclear Information System (INIS)

    Objective: To assess the characteristics of neuronal activity in human motor cortex after the seventh cervical nerve root transposition of the unaffected side by using functional MRI (fMRI). Methods: Thirteen patients who accepted the seventh cervical nerve root transposition of the unaffected side, due to total brachial plexus traction injury diagnosed by manifestation and operation, were examined retrospectively by using fMRI. 10 patients were injured on the left side and 3 on the right side. According to functional recovery of the affected hand, all subjects can be divided into 2 groups. The patients of the first group could not move the affected hand voluntarily. The patients of the second group could move the affected hand self-determined. 12 healthy volunteer's were also involved in this study as control. The fMRI examinations were performed by using echo-planer BOLD sequence. Then the SPM 99 software was used for post-processing. Results: The neuronal activation induced by the movement of both unaffected and affected upper' limb was seen in the contralateral PMC in all patients; Neuronal activation in the ipsilateral PMC evoked by movement of the unaffected extremity was seen in 10 cases, and induced by movement of the affected limb was seen in 7 cases. In the first group, the sharp of clusters in the contralateral PMC resulted by movement of the unaffected extremity showed normal in 9 eases, the average size of clusters resulted by the unaffected hand was 3159 (voxel), and resulted by the unaffected shoulder was 1746(voxel). The sharp of clusters in the contralateral PMC resulted by the affected shoulder or hand were revealed enlargement in 6 cases of each. In the second group, 1 case showed neuronal activation induced by movement of the affected limb in the PMC in both sides of motor cortex, and 2 cases showed neuronal activation in the contralateral PMC. Conclusions: Peripheral nerve injury was able to cause changes of motor cortex in human brain

  10. Root canal irrigants

    Directory of Open Access Journals (Sweden)

    Kandaswamy Deivanayagam

    2010-01-01

    Full Text Available Successful root canal therapy relies on the combination of proper instrumentation, irrigation, and obturation of the root canal. Of these three essential steps of root canal therapy, irrigation of the root canal is the most important determinant in the healing of the periapical tissues. The primary endodontic treatment goal must thus be to optimize root canal disinfection and to prevent reinfection. In this review of the literature, various irrigants and the interactions between irrigants are discussed. We performed a Medline search for English-language papers published untill July 2010. The keywords used were ′root canal irrigants′ and ′endodontic irrigants.′ The reference lists of each article were manually checked for additional articles of relevance.

  11. Root and shoot development, nutrition and uptake efficiency of macronutrients and zinc by upland rice cultivars as affected by phosphorus fertilizationDesenvolvimento radicular e aéreo, nutrição e eficiência de absorção de macronutrientes e zinco por cultivares de arroz de terras altas afetadas pela adubação fosfatada

    Directory of Open Access Journals (Sweden)

    Carlos Alexandre Costa Crusciol

    2013-10-01

    Full Text Available In Brazil, phosphorus availability is one factor that that more limit yield of upland rice under rainfed system. Then, better understanding of cultivars development at phosphorus soil fertilization is very important in the production systems making this more sustainable. The objective was to evaluate the influence of phosphorus doses applied to the soil over the root length, root and shoot dry matter, concentration and content of macronutrient and zinc in shoot and root system as well as the efficiency of nutrient absorption per meter root of upland cultivars of intermediate and modern groups. The experiment was carried out in greenhouse conditions in a completely randomized design in factorial scheme 4 x 4. Treatments were four levels of P fertilization applied at the soil (0, 50, 100 and 200 mg dm-3 of P and four upland rice cultivars (Maravilha – modern group, IAC-201, IAC-202 and Carajás – intermediate group. There is increase in phosphorus availability in the soil with increasing levels of P fertilization. Under low phosphorus availability, cultivars of the intermediate group have better shoots and root system development in relation to the modern cultivar group. Level of phosphorus affected nutrients contents in shoots and root system of upland rice cultivars. The increasing phosphorus fertilization increased absorption of nutrients per meter of root; and although under higher phosphorus availability there was a bigger root growth, in low phosphorus availability root growth was bigger at the expense of shoot growth. No Brasil, a disponibilidade de fósforo é um dos fatores que mais limita a produtividade do arroz de terras altas no sistema de sequeiro. Assim, o conhecimento do desenvolvimento das cultivares melhorados à níveis de fósforo no solo é de grande importância no manejo dos sistemas de produção, tornando-os mais sustentáveis. O objetivo deste trabalho foi avaliar a influência das doses de fósforo aplicados ao solo

  12. Roots and routes

    DEFF Research Database (Denmark)

    Christensen, Ann-Dorte; Jensen, Sune Qvotrup

    2011-01-01

    arguing that there is a dynamic interplay between roots and routes in people's lives. The empirical point of departure is narratives about roots and routes by ethnic minorities settled in Aalborg East, an underprivileged neighbourhood in northern Denmark. One of the main findings is a gap between the...... somewhat paradoxical finding is that it appears to be more difficult for transnational migrants to maintain their roots in the country of origin when they go back than it was to establish new roots in the host country...

  13. Roots of Dehn twists

    OpenAIRE

    McCullough, Darryl; Rajeevsarathy, Kashyap

    2009-01-01

    D. Margalit and S. Schleimer found examples of roots of the Dehn twist about a nonseparating curve in a closed orientable surface, that is, homeomorphisms whose nth power is isotopic to the Dehn twist. Our main theorem gives elementary number-theoretic conditions that describe the values of n for which an nth root exists, given the genus of the surface. Among its applications, we show that n must be odd, that the Margalit-Schleimer roots achieve the maximum value of n among the roots for a gi...

  14. Phosphate-dependent root system architecture responses to salt stress

    KAUST Repository

    Kawa, Dorota

    2016-05-20

    Nutrient availability and salinity of the soil affect growth and development of plant roots. Here, we describe how phosphate availability affects root system architecture (RSA) of Arabidopsis and how phosphate levels modulate responses of the root to salt stress. Phosphate (Pi) starvation reduced main root length and increased the number of lateral roots of Arabidopsis Col-0 seedlings. In combination with salt, low Pi dampened the inhibiting effect of mild salt stress (75mM) on all measured RSA components. At higher NaCl concentrations, the Pi deprivation response prevailed over the salt stress only for lateral root elongation. The Pi deprivation response of lateral roots appeared to be oppositely affected by abscisic acid (ABA) signaling compared to the salt stress response. Natural variation in the response to the combination treatment of salt and Pi starvation within 330 Arabidopsis accessions could be grouped into four response patterns. When exposed to double stress, in general lateral roots prioritized responses to salt, while the effect on main root traits was additive. Interestingly, these patterns were not identical for all accessions studied and multiple strategies to integrate the signals from Pi deprivation and salinity were identified. By Genome Wide Association Mapping (GWAS) 13 genomic loci were identified as putative factors integrating responses to salt stress and Pi starvation. From our experiments, we conclude that Pi starvation interferes with salt responses mainly at the level of lateral roots and that large natural variation exists in the available genetic repertoire of accessions to handle the combination of stresses.

  15. Integration of root phenes for soil resource acquisition

    Directory of Open Access Journals (Sweden)

    Larry Matthew York

    2013-09-01

    Full Text Available Suboptimal availability of water and nutrients is a primary limitation to plant growth in terrestrial ecosystems. The acquisition of soil resources by plant roots is therefore an important component of plant fitness and agricultural productivity. Plant root systems comprise a set of phenes, or traits, that interact. Phenes are the units of the plant phenotype, and phene states represent the variation in form and function a particular phene may take. Root phenes can be classified as affecting resource acquisition or utilization, influencing acquisition through exploration or exploitation, and in being metabolically influential or neutral. These classifications determine how one phene will interact with another phene, whether through foraging mechanisms or metabolic economics. Phenes that influence one another through foraging mechanisms are likely to operate within a phene module, a group of interacting phenes, that may be co-selected. Examples of root phene interactions discussed are: 1 root hair length × root hair density, 2 lateral branching × root cortical aerenchyma, 3 adventitious root number × adventitious root respiration and basal root growth angle, 4 nodal root number × root cortical aerenchyma, and 5 basal root growth angle × root hair length and density. Progress in the study of phenes and phene interactions will be facilitated by employing simulation modeling and near-isophenic lines that allow the study of specific phenes and phene combinations within a common phenotypic background. Developing a robust understanding of the phenome at the organismal level will require new lines of inquiry into how phenotypic integration influences plant function in diverse environments. A better understanding of how root phenes interact to affect soil resource acquisition will be an important tool in the breeding of crops with superior stress tolerance and reduced dependence on intensive use of inputs.

  16. Bioaccumulation of HMW PAHs in the roots of wild blackberry from the Bor region (Serbia): Phytoremediation and biomonitoring aspects.

    Science.gov (United States)

    Alagić, Slađana Č; Jovanović, Vesna P Stankov; Mitić, Violeta D; Cvetković, Jelena S; Petrović, Goran M; Stojanović, Gordana S

    2016-08-15

    In this work, the samples of roots and soils from the rooting zone of wild blackberry were collected from the urban-industrial and rural locations near "The Copper Mining and Smelting Complex Bor" (Serbia); they were analyzed by gas chromatographic-mass spectrometric method to determine the content of high-molecular weight polycyclic aromatic hydrocarbons (HMW PAHs). The obtained results were further processed using bio-concentration factor, Pearson's correlation study and hierarchical cluster analysis with the aim of investigating if they may be in favor of wild blackberry as a suitable plant for biomonitoring or phytoremediation purposes. In spite of the fact that numerous complex factors can affect the assimilation and accumulation of PAHs in plants, the obtained data expressed clearly many interesting specifics related to HMW PAH accumulation in roots of wild blackberry that naturally grows in an area, which is heavily polluted by heavy metals. The accumulation of individual PAH compounds in plant roots was at different level. The most abundant compound in all plant samples was benzo[a]pyrene and based on the results obtained for this environmental indicator of carcinogenic PAHs, it was possible to make several central conclusions: wild blackberry showed an excellent potential for its extraction from the soil and further accumulation in root tissues which indicate that this plant species may be applied in phytoremediation procedures based on mechanisms such as phytoextraction/phytoaccumulation in roots; phytostabilization and rhizodegradation are also possible as remediation mechanisms; utilization of plant roots in soil monitoring is possible but in this case, only the combination with soil data can provide correct information. PMID:27110970

  17. Clustering processes

    CERN Document Server

    Ryabko, Daniil

    2010-01-01

    The problem of clustering is considered, for the case when each data point is a sample generated by a stationary ergodic process. We propose a very natural asymptotic notion of consistency, and show that simple consistent algorithms exist, under most general non-parametric assumptions. The notion of consistency is as follows: two samples should be put into the same cluster if and only if they were generated by the same distribution. With this notion of consistency, clustering generalizes such classical statistical problems as homogeneity testing and process classification. We show that, for the case of a known number of clusters, consistency can be achieved under the only assumption that the joint distribution of the data is stationary ergodic (no parametric or Markovian assumptions, no assumptions of independence, neither between nor within the samples). If the number of clusters is unknown, consistency can be achieved under appropriate assumptions on the mixing rates of the processes. (again, no parametric ...

  18. Effects of Root-Growing Space on Its Absorbing Characteristics

    Institute of Scientific and Technical Information of China (English)

    SONG Hai-xing; LI Sheng-xiu

    2003-01-01

    Influences of root-growing space of maize upon root physiological characteristics, nutrient uptake and crop yields were studied under conditions with and without supply of water and N. Results showed that limitation of the root-growing space greatly affected root growth, decreased total root-absorbing area and TTC-reductive amounts. However, it obviously increased the root active-absorbing area, specific absorbing area (absorbing area per gram root weight) and specific active-absorbing area (actively absorbing area per gram root weight) in addition to promoting the TTC-reductive intensity. This clearly showed that plants were not passively tolerant to stress, but actively regulated their physiological metabolic processes, and strengthened their absorbing ability to increase water and nutrient uptake so that root injury by the environmental stress could be reduced. Supply of water and N stimulated root growth, increased root-absorbing area and activity, promoted nutrient uptake, and therefore increased crop yield and decreased the detrimental effects resulting from the limitation of roots-growing space.

  19. Considerations on immunization anxiety-related reactions in clusters

    Directory of Open Access Journals (Sweden)

    Ricardo Palacios

    2014-11-01

    Full Text Available A cluster of adverse events following immunization (AEFI represents a stress test for an immunization program. The community can suspect on vaccine-related reaction leading to mistrust on the immunization program. An immunization anxiety-related reaction is one of the hypotheses to be tested and can be reasonably accepted when the vaccine-related and immunization error-related reactions are ruled out and no coincidental events can explain the cases. Immunization program approaches widely accepted to understand and respond to adverse events are root-cause analysis and systems analysis. Psychiatric cognitive frame will support the root-cause analysis assigning a causal relationship to individual temporary disorders of the affected vaccinees. Communication will focus on vaccine safety and absence of errors in the immunization program. Systems analysis addresses the whole context considering the fear spread as a systemic threat. Socio-psychological frame offers a broader opportunity to understand and respond to a specific community. Management is based on communication to change community belief in misperceptions of vaccine risks and support the idea of immunization as a causal factor, different from the vaccine. Communities can consider use of psychiatric labels, Mass Psychogenic Illness or Mass Hysteria, as an act of inconsiderateness. Labels like immunization anxiety-related reactions in clusters or collective immunization anxiety-related reactions are recommended to bridge the causal perception of the community with the result of the scientific investigation of the cases.

  20. Crescimento radicular de soja em razão da sucessão de cultivos e da compactação do solo Soybean root growth as affected by previous crop and soil compaction

    Directory of Open Access Journals (Sweden)

    Rosemeire Helena da Silva

    2002-06-01

    Full Text Available O objetivo do experimento foi avaliar o crescimento radicular e produção de matéria seca da parte aérea da soja (Glycine max (L. Merrill cultivada após diversas espécies vegetais, em solo com diferentes níveis de compactação. O trabalho foi realizado em vasos contendo amostras de um Latossolo Vermelho, textura franco arenosa, com camada de 3,5 cm (profundidade de 15 a 18,5 cm compactada até as densidades 1,12, 1,36 e 1,60 Mg m-3, onde cultivaram-se anteriormente aveia-preta, guandu, milheto, mucuna-preta, soja, sorgo granífero e tremoço-azul, e um tratamento sem planta (pousio. Essas espécies se desenvolveram por 37 a 39 dias, foram cortadas ao nível do solo, picadas em partes de aproximadamente 3 cm e deixadas sobre a superfície do vaso por 40 dias. Após esse período, cultivou-se a soja até 28 dias após a emergência, quando, então, as plantas foram colhidas. Foram avaliados produção de matéria seca da parte aérea e de raízes, e comprimento e diâmetro radicular da soja. O cultivo anterior com aveia-preta, guandu e milheto favoreceu o crescimento radicular da soja abaixo de camadas compactadas do solo. Independentemente do nível de compactação, o cultivo anterior com qualquer das espécies estudadas beneficiou a produção de matéria seca da parte aérea da soja.This study aimed at evaluating root growth and shoot dry matter production of soybean (Glycine max (L. Merrill cropped after different vegetal species, in a soil with different compaction levels. The experiment was conducted in pots containing a Dark-Red Latosol (Acrortox, loamy sand, and the pots had a layer 3.5 cm (15 to 18.5 cm thick and 15 cm deep compacted to 1.12, 1.36 and 1.60 Mg m-3. Before soybean, the pots were cropped with black oat, pigeon pea, pearl millet, black mucuna, soybean, grain sorghum and lupin, plus a treatment without plants. These species were grown for 37 to 39 days, when they were cut at soil level, prick in particles of

  1. Chromatic roots and hamiltonian paths

    DEFF Research Database (Denmark)

    Thomassen, Carsten

    2000-01-01

    We present a new connection between colorings and hamiltonian paths: If the chromatic polynomial of a graph has a noninteger root less than or equal to t(n) = 2/3 + 1/3 (3)root (26 + 6 root (33)) + 1/3 (3)root (26 - 6 root (33)) = 1.29559.... then the graph has no hamiltonian path. This result is...

  2. Atributos químicos e perfil de enraizamento de milho influenciados pela calagem em semeadura direta Chemical attributes and corn root system development as affected by liming in no-till

    Directory of Open Access Journals (Sweden)

    Gabriel Henrique Melo Nascimento Leite

    2006-08-01

    ,20-0,30 m. Mesmo sob condições químicas adversas, em todos os tratamentos, o milho apresentou crescimento de raízes até 0,45 m de profundidade. O tratamento 100I apresentou maior crescimento de raízes até 0,15-0,20 m de profundidade do que os tratamentos com doses menores de calcário em superfície (50S e 25S, onde as raízes se concentraram na camada até 0,075 m. A incorporação do calcário proporcionou maior uniformidade na neutralização da acidez do solo em profundidade, o que se refletiu em maior quantidade de raízes até 0,45 m.In Rio Grande do Sul state, the area cultivated with under no-till system now amounts to 60 % of the total rain-fed cultivated area. However, there are still doubts as to crop practices in this soil conservation system, such as liming and fertilization as well as regarding root growth and crop productivity. The objective of this study was to evaluate the effects of lime doses and application forms on corn root development. The experiment was carried out in 1999/2000, in the experimental area of the Soil Science Department of the Federal University of Santa Maria, state of Rio Grande do Sul, Brazil, in a random block design in split plots, with four replications. The soil under study was a typical Hapludalf with 2 % slope. Main treatments were: no lime (SC, incorporation of 100 % of the recommended dose (100I, and 25 % (25S, 50 % (50S and 100 % (100S of the recommended dose (6.8 t ha-1 distributed over the soil surface. Lime was incorporated with conventional tillage in February 1996. Using the "nail board" method, with dimensions of 0,20 x 0,30 m, 0,30 x 0,45 m and 0,45 x 0,70 m, monoliths were taken from the soil profile, parallel to the corn sowing furrow, at 20, 54 and 80 days after corn emergence (DAE. The monoliths were carefully washed and the roots counted to establish a corn rooting profile in each treatment. Increasing lime doses applied on the soil surface (25S, 50S and 100S increased the depth at which elevations in p

  3. Fine roots and ectomycorrhizas as indicators of environmental change

    OpenAIRE

    Cudlin, Pavel; Kieliszewska-Rokicka, B.; Rudawska, M.; Grebenc, Tine; Alberton, O.; Lehto, T.; Bakker, M.R.; Børja, I.; B. Konôpka; Leski, T.; Kraigher, Hojka; Kuyper, T.W.

    2007-01-01

    Human-induced and natural stress factors can affect fine roots and ectomycorrhizas. Therefore they have potential utility as indicators of environmental change. We evaluated, through meta-analysis, the magnitude of the effects of acidic deposition, nitrogen deposition, increased ozone levels, elevated atmospheric carbon dioxide, and drought on fine roots and ectomycorrhizal (ECM) characteristics. Ectomycorrhizal colonization was an unsuitable parameter for environmental change, but fine root ...

  4. Fine roots and ectomycorrhizas as indicators of environmental change

    OpenAIRE

    Kraigher, Hojka; Grebenc, Tine; Cudlin, Pavel

    2015-01-01

    Human-induced and natural stress factors can affect fine roots and ectomycorrhizas. Therefore they have potential utility as indicators of environmental change. We evaluated, through meta-analysis, the magnitude of the effects of acidic deposition, nitrogen deposition, increased ozone levels, elevated atmospheric carbon dioxide, and drought on fine roots and ectomycorrhizal (ECM) characteristics. Ectomycorrhizal colonization was an unsuitable parameter for environmental change, but fine root ...

  5. Cinnamic Acid Increases Lignin Production and Inhibits Soybean Root Growth

    OpenAIRE

    Victor Hugo Salvador; Rogério Barbosa Lima; Wanderley Dantas dos Santos; Anderson Ricardo Soares; Paulo Alfredo Feitoza Böhm; Rogério Marchiosi; Maria de Lourdes Lucio Ferrarese; Osvaldo Ferrarese-Filho

    2013-01-01

    Cinnamic acid is a known allelochemical that affects seed germination and plant root growth and therefore influences several metabolic processes. In the present work, we evaluated its effects on growth, indole-3-acetic acid (IAA) oxidase and cinnamate 4-hydroxylase (C4H) activities and lignin monomer composition in soybean ( Glycine max ) roots. The results revealed that exogenously applied cinnamic acid inhibited root growth and increased IAA oxidase and C4H activities. The allelochemical in...

  6. Repair of horizontal root fracture: A case report

    OpenAIRE

    Laila Shafie; Farhad Farzaneh; Maryam Alsadat Hashemipour

    2011-01-01

    ABSTRACT: Horizontal root fractures in permanent teeth are uncommon injuries among dental traumas. The principle of treating horizontal root fractures of permanent teeth is repositioning and fixation of fractured segment. Diagnosis of tooth fractures based on radiographic findings and the fracture healing process are affected by factors before and after injury. The present case reports the treatment of horizontal root fracture located at the apical-third of upper left and right central inciso...

  7. Clustering analysis

    International Nuclear Information System (INIS)

    Cluster analysis is the name of group of multivariate techniques whose principal purpose is to distinguish similar entities from the characteristics they process.To study this analysis, there are several algorithms that can be used. Therefore, this topic focuses to discuss the algorithms, such as, similarity measures, and hierarchical clustering which includes single linkage, complete linkage and average linkage method. also, non-hierarchical clustering method, which is popular name K-mean method' will be discussed. Finally, this paper will be described the advantages and disadvantages of every methods

  8. Cluster editing

    DEFF Research Database (Denmark)

    Böcker, S.; Baumbach, Jan

    2013-01-01

    The Cluster Editing problem asks to transform a graph into a disjoint union of cliques using a minimum number of edge modifications. Although the problem has been proven NP-complete several times, it has nevertheless attracted much research both from the theoretical and the applied side. The...... algorithms for biological problems. © 2013 Springer-Verlag....... problem has been the inspiration for numerous algorithms in bioinformatics, aiming at clustering entities such as genes, proteins, phenotypes, or patients. In this paper, we review exact and heuristic methods that have been proposed for the Cluster Editing problem, and also applications of these...

  9. Cluster analysis

    CERN Document Server

    Everitt, Brian S; Leese, Morven; Stahl, Daniel

    2011-01-01

    Cluster analysis comprises a range of methods for classifying multivariate data into subgroups. By organizing multivariate data into such subgroups, clustering can help reveal the characteristics of any structure or patterns present. These techniques have proven useful in a wide range of areas such as medicine, psychology, market research and bioinformatics.This fifth edition of the highly successful Cluster Analysis includes coverage of the latest developments in the field and a new chapter dealing with finite mixture models for structured data.Real life examples are used throughout to demons

  10. Effect of root canal preparation, type of endodontic post and mechanical cycling on root fracture strength

    Directory of Open Access Journals (Sweden)

    Marília Pivetta RIPPE

    2014-06-01

    Full Text Available Objective: To evaluate the impact of the type of root canal preparation, intraradicular post and mechanical cycling on the fracture strength of roots. Material and Methods: eighty human single rooted teeth were divided into 8 groups according to the instruments used for root canal preparation (manual or rotary instruments, the type of intraradicular post (fiber posts- FRC and cast post and core- CPC and the use of mechanical cycling (MC as follows: Manual and FRC; Manual, FRC and MC; Manual and CPC; Manual, CPC and MC; Rotary and FRC; Rotary, FRC and MC; Rotary and CPC; Rotary, CPC and MC. The filling was performed by lateral compactation. All root canals were prepared for a post with a 10 mm length, using the custom #2 bur of the glass fiber post system. For mechanical cycling, the protocol was applied as follows: an angle of incidence of 45°, 37°C, 88 N, 4 Hz, 2 million pulses. All groups were submitted to fracture strength test in a 45° device with 1 mm/ min cross-head speed until failure occurred. Results: The 3-way ANOVA showed that the root canal preparation strategy (p<0.03 and post type (p<0.0001 affected the fracture strength results, while mechanical cycling (p=0.29 did not. Conclusion: The root canal preparation strategy only influenced the root fracture strength when restoring with a fiber post and mechanical cycling, so it does not seem to be an important factor in this scenario.

  11. Spitzer Clusters

    Science.gov (United States)

    Krick, Kessica

    This proposal is a specific response to the strategic goal of NASA's research program to "discover how the universe works and explore how the universe evolved into its present form." Towards this goal, we propose to mine the Spitzer archive for all observations of galaxy groups and clusters for the purpose of studying galaxy evolution in clusters, contamination rates for Sunyaev Zeldovich cluster surveys, and to provide a database of Spitzer observed clusters to the broader community. Funding from this proposal will go towards two years of support for a Postdoc to do this work. After searching the Spitzer Heritage Archive, we have found 194 unique galaxy groups and clusters that have data from both the Infrared array camera (IRAC; Fazio et al. 2004) at 3.6 - 8 microns and the multiband imaging photometer for Spitzer (MIPS; Rieke et al. 2004) at 24microns. This large sample will add value beyond the individual datasets because it will be a larger sample of IR clusters than ever before and will have sufficient diversity in mass, redshift, and dynamical state to allow us to differentiate amongst the effects of these cluster properties. An infrared sample is important because it is unaffected by dust extinction while at the same time is an excellent measure of both stellar mass (IRAC wavelengths) and star formation rate (MIPS wavelengths). Additionally, IRAC can be used to differentiate star forming galaxies (SFG) from active galactic nuclei (AGN), due to their different spectral shapes in this wavelength regime. Specifically, we intend to identify SFG and AGN in galaxy groups and clusters. Groups and clusters differ from the field because the galaxy densities are higher, there is a large potential well due mainly to the mass of the dark matter, and there is hot X-ray gas (the intracluster medium; ICM). We will examine the impact of these differences in environment on galaxy formation by comparing cluster properties of AGN and SFG to those in the field. Also, we will

  12. Cluster Bulleticity

    OpenAIRE

    Massey, Richard; Kitching, Thomas D.; Nagai, Daisuke

    2010-01-01

    The unique properties of dark matter are revealed during collisions between clusters of galaxies, like the bullet cluster (1E 0657-56) and baby bullet (MACSJ0025-12). These systems provide evidence for an additional, invisible mass in the separation between the distribution of their total mass, measured via gravitational lensing, and their ordinary 'baryonic' matter, measured via its X-ray emission. Unfortunately, the information available from these systems is limited by th...

  13. Cluster Bulleticity

    OpenAIRE

    Massey, R; Kitching, T.; Nagai, D.

    2010-01-01

    The unique properties of dark matter are revealed during collisions between clusters of galaxies, such as the bullet cluster (1E 0657−56) and baby bullet (MACS J0025−12). These systems provide evidence for an additional, invisible mass in the separation between the distributions of their total mass, measured via gravitational lensing, and their ordinary ‘baryonic’ matter, measured via its X-ray emission. Unfortunately, the information available from these systems is limited by their rarity. C...

  14. Cluster generator

    Science.gov (United States)

    Donchev, Todor I.; Petrov, Ivan G.

    2011-05-31

    Described herein is an apparatus and a method for producing atom clusters based on a gas discharge within a hollow cathode. The hollow cathode includes one or more walls. The one or more walls define a sputtering chamber within the hollow cathode and include a material to be sputtered. A hollow anode is positioned at an end of the sputtering chamber, and atom clusters are formed when a gas discharge is generated between the hollow anode and the hollow cathode.

  15. ROOT User Workshop 2013

    CERN Document Server

    2013-01-01

    Since almost two decades, ROOT has established itself as the framework for HENP data processing and analysis. The LHC upgrade program and the new experiments being designed at CERN and elsewhere will pose even more formidable challenges in terms of data complexity and size. The new parallel and heterogeneous computing architectures that are either announced or already available will call for a deep rethinking of the code and the data structures to be exploited efficiently. This workshop, following from a successful series of such events, will allow you to learn in detail about the new ROOT 6 and will help shape the future evolution of ROOT.

  16. Root distributions in a laboratory box evaluated using two different techniques (gravimetric and image processing and their impact on root water uptake simulated with HYDRUS

    Directory of Open Access Journals (Sweden)

    Klement Aleš

    2016-06-01

    Full Text Available Knowledge of the distribution of plant roots in a soil profile (i.e. root density is needed when simulating root water uptake from soil. Therefore, this study focused on evaluating barley and wheat root densities in a sand-vermiculite substrate. Barley and wheat were planted in a flat laboratory box under greenhouse conditions. The box was always divided into two parts, where a single plant row and rows cross section (respectively was simulated. Roots were excavated at the end of the experiment and root densities were assessed using root zone image processing and by weighing. For this purpose, the entire area (width of 40 and height of 50 cm of each scenario was divided into 80 segments (area of 5×5 cm. Root density in each segment was expressed as a root percentage of the entire root cluster. Vertical root distributions (i.e. root density with respect to depth were also calculated as a sum of root densities in each 5 cm layer. Resulting vertical root densities, measured evaporation from the water table (used as the potential root water uptake, and the Feddes stress response function model were used for simulating substrate water regime and actual root water uptake for all scenarios using HYDRUS-1D. All scenarios were also simulated using HYDRUS-2D. One scenario (areal root density of barley sown in a single row, obtained using image analysis is presented in this paper (because most scenarios showed root water uptakes similar to results of 1D scenarios.

  17. Characterization of alfalfa populations contrasting for root system architecture (RSA)

    Science.gov (United States)

    The root system architecture affects the capacity for nutrient and water uptake thus impacting biomass yield production and may contribute to the persistence of perennial plants. The objectives of this study were to phenotype the roots of three alfalfa populations and identify differences between di...

  18. Shoot-supplied ammonium targets the root auxin influx carrier AUX1 and inhibits lateral root emergence in Arabidopsis

    KAUST Repository

    Li, Baohai

    2011-03-24

    Deposition of ammonium (NH4 +) from the atmosphere is a substantial environmental problem. While toxicity resulting from root exposure to NH4 + is well studied, little is known about how shoot-supplied ammonium (SSA) affects root growth. In this study, we show that SSA significantly affects lateral root (LR) development. We show that SSA inhibits lateral root primordium (LRP) emergence, but not LRP initiation, resulting in significantly impaired LR number. We show that the inhibition is independent of abscisic acid (ABA) signalling and sucrose uptake in shoots but relates to the auxin response in roots. Expression analyses of an auxin-responsive reporter, DR5:GUS, and direct assays of auxin transport demonstrated that SSA inhibits root acropetal (rootward) auxin transport while not affecting basipetal (shootward) transport or auxin sensitivity of root cells. Mutant analyses indicated that the auxin influx carrier AUX1, but not the auxin efflux carriers PIN-FORMED (PIN)1 or PIN2, is required for this inhibition of LRP emergence and the observed auxin response. We found that AUX1 expression was modulated by SSA in vascular tissues rather than LR cap cells in roots. Taken together, our results suggest that SSA inhibits LRP emergence in Arabidopsis by interfering with AUX1-dependent auxin transport from shoot to root. © 2011 Blackwell Publishing Ltd.

  19. Quantitative measurements of root water uptake and root hydraulic conductivities

    Science.gov (United States)

    Zarebanadkouki, Mohsen; Javaux, Mathieu; Meunier, Felicien; Couvreur, Valentin; Carminati, Andrea

    2016-04-01

    How is root water uptake distributed along the root system and what root properties control this distribution? Here we present a method to: 1) measure root water uptake and 2) inversely estimate the root hydraulic conductivities. The experimental method consists in using neutron radiography to trace deuterated water (D2O) in soil and roots. The method was applied to lupines grown aluminium containers filled with a sandy soil. When the lupines were 4 weeks old, D2O was locally injected in a selected soil regions and its transport was monitored in soil and roots using time-series neutron radiography. By image processing, we quantified the concentration of D2O in soil and roots. We simulated the transport of D2O into roots using a diffusion-convection numerical model. The diffusivity of the roots tissue was inversely estimated by simulating the transport of D2O into the roots during night. The convective fluxes (i.e. root water uptake) were inversely estimating by fitting the experiments during day, when plants were transpiring, and assuming that root diffusivity did not change. The results showed that root water uptake was not uniform along the roots. Water uptake was higher at the proximal parts of the lateral roots and it decreased by a factor of 10 towards the distal parts. We used the data of water fluxes to inversely estimate the profile of hydraulic conductivities along the roots of transpiring plants growing in soil. The water fluxes in the lupine roots were simulated using the Hydraulic Tree Model by Doussan et al. (1998). The fitting parameters to be adjusted were the radial and axial hydraulic conductivities of the roots. The results showed that by using the root architectural model of Doussan et al. (1998) and detailed information of water fluxes into different root segments we could estimate the profile of hydraulic conductivities along the roots. We also found that: 1) in a tap-rooted plant like lupine water is mostly taken up by lateral roots; (2) water

  20. Roots at the percolation threshold

    Science.gov (United States)

    Kroener, Eva; Ahmed, Mutez Ali; Carminati, Andrea

    2015-04-01

    The rhizosphere is the layer of soil around the roots where complex and dynamic interactions between plants and soil affect the capacity of plants to take up water. The physical properties of the rhizosphere are affected by mucilage, a gel exuded by roots. Mucilage can absorb large volumes of water, but it becomes hydrophobic after drying. We use a percolation model to describe the rewetting of dry rhizosphere. We find that at a critical mucilage concentration the rhizosphere becomes impermeable. The critical mucilage concentration depends on the radius of the soil particle size. Capillary rise experiments with neutron radiography prove that for concentrations below the critical mucilage concentration water could easily cross the rhizosphere, while above the critical concentration water could no longer percolate through it. Our studies, together with former observations of water dynamics in the rhizosphere, suggest that the rhizosphere is near the percolation threshold, where small variations in mucilage concentration sensitively alter the soil hydraulic conductivity. Is mucilage exudation a plant mechanism to efficiently control the rhizosphere conductivity and the access to water?

  1. Genetic association among root morphology, root quality and root yield in ashwagandha (Withania somnifera

    Directory of Open Access Journals (Sweden)

    Kumar Ramesh R.

    2011-01-01

    Full Text Available Ashwagandha (Withania somnifera is a dryland medicinal crop and roots are used as valuable drug in traditional systems of medicine. Morphological variants (morphotypes and the parental populations were evaluated for root - morphometric, quality and yield traits to study genetic association among them. Root morphometric traits (root length, root diameter, number of secondary roots/ plant and crude fiber content exhibited strong association among them and showed significant positive genotypic correlation with yield. Starch-fiber ratio (SFR, determinant of brittle root texture showed strong negative association with root yield. The total alkaloid content had positive genotypic correlation with root yield. So genetic upgradation should aim at optimum balance between two divergent groups of traits i.e. root yield traits (root morphometric traits and crude fiber content and root textural quality traits (starch content and SFR to develop superior genotypes with better yield and quality.

  2. Tomato Root Response to Subsurface Drip Irrigation

    Institute of Scientific and Technical Information of China (English)

    ZHUGE Yu-Ping; ZHANG Xu-Dong; ZHANG Yu-Long; LI Jun; YANG Li-Juan; HUANG Yi; LIU Ming-Da

    2004-01-01

    Four depth treatments of subsurface drip irrigation pipes were designated as 1) at 20,2) 30 and 3) 40 cm depths all with a drip-proof flumes underneath,and 4) at 30 cm without a drip-proof flume to investigate the responses of a tomato root system to different technical parameters of subsurface drip irrigation in a glass greenhouse,to evaluate tomato growth as affected by subsurface drip irrigation,and to develop an integrated subsurface drip irrigation method for optimal tomato yield and water use in a glass greenhouse. Tomato seedlings were planted above the subsurface drip irrigation pipe. Most of the tomato roots in treatment 1 were found in the top 0-20 cm soil depth with weak root activity but with yield and water use efficiency (WUE) significantly less (P ---- 0.05) than treatment 2; root activity and tomato yield were significantly higher (P = 0.05) with treatment 3 compared to treatment 1; and with treatment 2 the tomato roots and shoots grew harmoniously with root activity,nutrient uptake,tomato yield and WUE significantly higher (P= 0.05) or as high as the other treatments. These findings suggested that subsurface drip irrigation with pipes at 30 cm depth with a drip-proof flume placed underneath was best for tomato production in greenhouses. In addition,the irrigation interval should be about 7-8 days and the irrigation rate should be set to 225 m3 ha-1 per event.

  3. Desenvolvimento Vegetativo e morfologia radicular de citrange carrizo afetado por ácido indolbutírico e micorrizas arbusculares Vegetative development and root morphology of carrizo citrange affected by indolebutyric acid and arbuscular mycorrhizal fungi

    Directory of Open Access Journals (Sweden)

    Paulo Vitor Dutra de Souza

    2000-04-01

    Full Text Available Este estudo foi realizado na localidade de Alcanar (Tarragona, Espanha e objetivou avaliar o efeito de cinco concentrações do ácido indolbutírico (AIB (0,0; 0,5; 1,0; 1,5; 2,0 g/L e da inoculação com micorrizas arbusculares (MA (Glomus intraradices Schenck & Smith sobre o desenvolvimento vegetativo, conteúdo foliar de P e K e morfologia radicular de plântulas de citrange Carrizo (Citrus sinensis (L. X Poncirus trifoliata (L. Raf.. Utilizou-se o delineamento experimental de blocos completos casualisados em esquema fatorial, com 4 repetições e 10 plantas por parcela. A aplicação de AIB não alterou o desenvolvimento vegetativo das plântulas cultivadas em ausência de MA, apesar de haver incrementado a quantidade de P e K e a espessura dos feixes vasculares. As MA incrementaram o conteúdo de P foliar. Encontrou-se uma interação positiva entre o AIB e as MA, pois as plântulas micorrizadas apresentaram um incremento no desenvolvimento vegetativo, nos conteúdos foliares de P e K e na espessura dos feixes vasculares com o aumento das concentrações de AIB.This study was carried out in Alcanar (Tarragona - Spain to evaluate the effect of five indolebutyric acid (IBA concentrations (0.0; 0.5; 1.0; 1.5; 2.0 g/L and inoculation with arbuscular mycorrhizae fungi (AMF (Glomus intraradices Schenck & Smith on Carrizo citrange (Citrus sinensis (L. x Poncirus trifoliata (L. Raf. vegetative development, P and K foliar contents and root morphology. The experimental design was in a Completly Randomized Block Design with 10 seedlings per plot and 4 replicates. The IBA concentrations had no effect on vegetative development of nonmycorrhizal seedlings, althougt it had increased P and K foliar contents and primary xylem tickness. AMF increased P foliar content. IBA x AMF interaction was observed, increasing IBA concentrations on mycorrhizal seedlings resulted in increased in vegetative development, P and K foliar contents and primary xylem thickness.

  4. Peroxidase activity in roots of arracacha affected by pH and temperature = Atividade da peroxidase em raízes de batata-baroa afetada pelo pH e temperatura

    Directory of Open Access Journals (Sweden)

    Luciana Nunes Menolli

    2011-07-01

    Full Text Available In this paper, roots of arracacha (Arracacia xanthorrhyza Bancroft were stored at 5ºC to induce chilling injury symptoms and stress-related peroxidase activity. Later, peroxidase kinetic activity was determined in different pH and temperature conditions. For this, soluble crude extract was sequentially saturated with ammonium sulfate, obtaining a semi-purified enzyme solution used for the analysis. Activity of peroxidase induced by the chilling at 5oC was determined from pH 2.5 to 9.0 and at temperature ranging from 10 to80oC. The peroxidase had higher activity when the reaction occurred between pH 5.5 and 6.0 and at temperature of 30oC. Complete inactivation of the activity was observed in pH 2.5 after 60 minutes of pre-incubation or at 60oC for 10 minutes or alternatively at 70oCafter 5 minutes of pre-incubation. The enzyme is more susceptible to inactivation in acid than alkaline pHs or alternatively using heat treatment.Neste trabalho, raízes de batata-baroa (Arracacia xanthorrhiza Bancroft foram armazenadas a 5oC para induzir injúria por frio e expressar atividade da peroxidase de estresse. Posteriormente, a cinética de atividade foi determinada em diferentes condições depHs e temperatura. Para isto, extrato solúvel da raiz foi sequencialmente saturado com sulfato de amônio, obtendo-se uma preparação semi-purificada para a análise enzimática. Atividade peroxidativa induzida pela temperatura de armazenamento de 5oC foideterminada em pHs de 2,5 a 9,0 e a temperaturas de 10 a 80oC. A atividade da peroxidase foi maior quando a reação foi realizada nos pHs de 5,5 e 6,0 e temperatura de 30oC. A inativação completa da enzima ocorreu em pH de 2,5 após 60 min. de pré-incubação ou a60oC por 10 min., e alternativamente a 70oC após 5 min. de pré-incubação. A enzima foi mais susceptível à inativação em pH ácido do que alcalino, podendo também ser inativada pelo tratamento de calor.

  5. An Energy Distance Aware Clustering Protocol with Dual Cluster Heads Using Niching Particle Swarm Optimization for Wireless Sensor Networks

    OpenAIRE

    Dexin Ma; Pengmin Xu

    2015-01-01

    Energy efficient utilization is an important criteria and factor that affects the design of wireless sensor networks (WSNs). In this literature, we propose an energy distance aware clustering protocol with Dual Cluster Heads using Niching Particle Swarm Optimization (DCH-NPSO). The protocol selects two cluster heads in each cluster, the Master Cluster Head (MCH) and the Slave Cluster Head (SCH), and the selection needs to consider the network state information carefully and deliberately. Simu...

  6. Denominators of cluster variables

    OpenAIRE

    Buan, Aslak Bakke; Marsh, Robert J.; Reiten, Idun

    2007-01-01

    Associated to any acyclic cluster algebra is a corresponding triangulated category known as the cluster category. It is known that there is a one-to-one correspondence between cluster variables in the cluster algebra and exceptional indecomposable objects in the cluster category inducing a correspondence between clusters and cluster-tilting objects. Fix a cluster-tilting object T and a corresponding initial cluster. By the Laurent phenomenon, every cluster variable can be written as a Laurent...

  7. Is Regional Root Reinforcement Controlled by Soil Moisture Variability?

    Science.gov (United States)

    Hales, T.; Ford, C. R.

    2011-12-01

    Climate change will alter the amount, type (i.e., snow vs. rain), and timing of precipitation that controls many hazardous Earth surface processes, including debris flows. Most GCMs agree that as climate warms the frequency of extreme precipitation will increase across the globe. Debris flow events triggered by heavy precipitation will likely also increase. Precipitation also affects the resistance to debris flow initiation by controlling belowground plant hydraulic architecture (e.g. root frequency, diameter distribution, tensile strength). Quantifying the links between precipitation, below ground properties, and the processes that initiate debris flows are therefore critical to understanding future hazard. To explore these links, we conducted a field experiment in the Coweeta Hydrologic Laboratory by excavating 12 soil pits (~1 m3), from two topographies (noses, hollows), and two tree species (Liriodendron tulipifera and Betula lenta). For each species and topography, we collected all biomass from five soil depths and measured soil moisture at 30, 60, and 90cm depth. For each depth we also measured root tensile strength, root cellulose content. Where we collected soil moisture data, we also measured root and soil hydraulic conductivity. Our data show a link between soil moisture content and root biomass distribution; root biomass is more evenly distributed through the soil column in hollows compared to noses. This relationship is consistent with the hypothesis that more consistent soil moisture in hollows allows plant roots to access resources from deeper within the soil column. This physiologic control has a significant effect on root cohesion, with trees on noses (or lower average soil moisture) providing greater root cohesion close to the surface, but considerably less cohesion at depth. Root tensile strength correlated with local daily soil moisture rather than the long term differences represented by noses and hollows. Daily soil moisture affected the amount

  8. Glucose and auxin signaling interaction in controlling Arabidopsis thaliana seedlings root growth and development.

    Directory of Open Access Journals (Sweden)

    Bhuwaneshwar S Mishra

    Full Text Available BACKGROUND: Plant root growth and development is highly plastic and can adapt to many environmental conditions. Sugar signaling has been shown to affect root growth and development by interacting with phytohormones such as gibberellins, cytokinin and abscisic acid. Auxin signaling and transport has been earlier shown to be controlling plant root length, number of lateral roots, root hair and root growth direction. PRINCIPAL FINDINGS: Increasing concentration of glucose not only controls root length, root hair and number of lateral roots but can also modulate root growth direction. Since root growth and development is also controlled by auxin, whole genome transcript profiling was done to find out the extent of interaction between glucose and auxin response pathways. Glucose alone could transcriptionally regulate 376 (62% genes out of 604 genes affected by IAA. Presence of glucose could also modulate the extent of regulation 2 fold or more of almost 63% genes induced or repressed by IAA. Interestingly, glucose could affect induction or repression of IAA affected genes (35% even if glucose alone had no significant effect on the transcription of these genes itself. Glucose could affect auxin biosynthetic YUCCA genes family members, auxin transporter PIN proteins, receptor TIR1 and members of a number of gene families including AUX/IAA, GH3 and SAUR involved in auxin signaling. Arabidopsis auxin receptor tir1 and response mutants, axr2, axr3 and slr1 not only display a defect in glucose induced change in root length, root hair elongation and lateral root production but also accentuate glucose induced increase in root growth randomization from vertical suggesting glucose effects on plant root growth and development are mediated by auxin signaling components. CONCLUSION: Our findings implicate an important role of the glucose interacting with auxin signaling and transport machinery to control seedling root growth and development in changing nutrient

  9. Molecular dynamics simulation of melting behaviours of supported cobalt cluster

    International Nuclear Information System (INIS)

    The molecular dynamics simulation combined with the simulated annealing method are used to study the melting behaviors of free cobalt clusters and two kinds of supported cobalt clusters with cluster size ranging from 400 to 2000 atoms. Gupta potential is used for the cobalt - cobalt interactions in Co clusters. Influences on the melting properties are discussed with two kinds of supported potentials: the Lennard-Jones potential and the Morse potential. Our results reveal that with the same number of cobalt atoms and the same cobalt-substrate interation stength, the melting points and pre-melting intervals of the two kinds of supported Co clusters are all in reasonable agreement with each other. With increasing the depth of supported potential, the melting points increase for the supported cluster. Similar to the case of free clusters, the linear relation between the melting point and the inverse of cluster's size cube root is also found for the two kinds of supported clusters. (authors)

  10. Burkholderia Species Are Major Inhabitants of White Lupin Cluster Roots▿†

    OpenAIRE

    Weisskopf, Laure; Heller, Stefanie; Eberl, Leo

    2011-01-01

    The formation of cluster roots by plants represents a highly efficient strategy for acquisition of sparingly available phosphate. This particular root type is characterized by a densely branched structure and high exudation of organic acids and protons, which are likely to influence the resident bacterial community. Until now, the identity of the bacterial populations living in cluster roots has not been investigated. We applied cultivation-dependent and cultivation-independent methods to cha...

  11. Identifying root system genes using induced mutants in barley

    International Nuclear Information System (INIS)

    Root systems play an important role in plant growth and development. They absorb water and nutrients, anchor plant in the soil and affect plant tolerance to various abiotic stresses. Despite their importance, the progress in understanding the molecular processes underlying root development has been achieved only in Arabidopsis thaliana. It was accomplished through detailed analysis of root mutants with the use of advanced molecular, genomic and bioinformatic tools. Recently, similar studies performed with rice and maize root mutants have led to the identification of homologous and novel genes controlling root system formation in monocots. The collection of barley mutants with changes in root system development and morphology has been developed in our Department after mutagenic treatments of spring barley varieties with N-methyl N-nitosourea (MNU) and sodium azide. Among these mutants, the majority was characterized by seminal roots significantly shorter than roots of a parent variety throughout a whole vegetation period. Additionally, several mutants with root hairs impaired at different stages of development have been identified. These mutants have become the material of studies aimed at genetic and molecular dissection of seminal root and root hair formation in barley. The studies included the molecular mapping of genes responsible for mutant phenotype using DNA markers and root transcriptome analysis in the mutant/parent variety system. Using cDNA RDA approach, we have identified the HvEXPB1 gene encoding root specific beta expansin related to the root hair initiation in barley. We have also initiated the database search for barley sequences homologous to the known Arabodopsis, maize and rice genes. The identified homologous ESTs are now used for isolation of the complete coding sequences and gene function will be validated through identification of mutations related to the altered phenotype. This work was supported by the IAEA Research Contracts 12611 and 12849

  12. Cluster Bulleticity

    CERN Document Server

    Massey, Richard; Nagai, Daisuke

    2010-01-01

    The unique properties of dark matter are revealed during collisions between clusters of galaxies, like the bullet cluster (1E 0657-56) and baby bullet (MACSJ0025-12). These systems provide evidence for an additional, invisible mass in the separation between the distribution of their total mass, measured via gravitational lensing, and their ordinary 'baryonic' matter, measured via its X-ray emission. Unfortunately, the information available from these systems is limited by their rarity. Constraints on the properties of dark matter, such as its interaction cross-section, are therefore restricted by uncertainties in the individual systems' impact velocity, impact parameter and orientation with respect to the line of sight. Here we develop a complementary, statistical measurement in which every piece of substructure falling into every massive cluster is treated as a bullet. We define 'bulleticity' as the mean separation between dark matter and ordinary matter, and we measure a positive signal in hydrodynamical si...

  13. The "Green" Root Beer Laboratory

    Science.gov (United States)

    Clary, Renee; Wandersee, James

    2010-01-01

    No, your students will not be drinking green root beer for St. Patrick's Day--this "green" root beer laboratory promotes environmental awareness in the science classroom, and provides a venue for some very sound science content! While many science classrooms incorporate root beer-brewing activities, the root beer lab presented in this article has…

  14. Fuzzy Clustering

    DEFF Research Database (Denmark)

    Berks, G.; Keyserlingk, Diedrich Graf von; Jantzen, Jan;

    2000-01-01

    and clustering are the basic concerns in medicine. Classification depends on definitions of the classes and their required degree of participant of the elements in the cases' symptoms. In medicine imprecise conditions are the rule and therefore fuzzy methods are much more suitable than crisp ones...

  15. Quotients of cluster categories

    OpenAIRE

    Jorgensen, Peter

    2007-01-01

    Higher cluster categories were recently introduced as a generalization of cluster categories. This paper shows that in Dynkin types A and D, half of all higher cluster categories are actually just quotients of cluster categories. The other half can be obtained as quotients of 2-cluster categories, the "lowest" type of higher cluster categories. Hence, in Dynkin types A and D, all higher cluster phenomena are implicit in cluster categories and 2-cluster categories. In contrast, the same is not...

  16. Comparative RNA-Seq Analysis Reveals That Regulatory Network of Maize Root Development Controls the Expression of Genes in Response to N Stress.

    Directory of Open Access Journals (Sweden)

    Xiujing He

    Full Text Available Nitrogen (N is an essential nutrient for plants, and it directly affects grain yield and protein content in cereal crops. Plant root systems are not only critical for anchorage in the soil, but also for N acquisition. Therefore, genes controlling root development might also affect N uptake by plants. In this study, the responses of nitrogen on root architecture of mutant rtcs and wild-type of maize were investigated by morphological and physiological analysis. Subsequently, we performed a comparative RNA-Seq analysis to compare gene expression profiles between mutant rtcs roots and wild-type roots under different N conditions. We identified 786 co-modulated differentially expressed genes (DEGs related to root development. These genes participated in various metabolic processes. A co-expression cluster analysis and a cis-regulatory motifs analysis revealed the importance of the AP2-EREBP transcription factor family in the rtcs-dependent regulatory network. Some genotype-specific DEGs contained at least one LBD motif in their promoter region. Further analyses of the differences in gene transcript levels between rtcs and wild-type under different N conditions revealed 403 co-modulated DEGs with distinct functions. A comparative analysis revealed that the regulatory network controlling root development also controlled gene expression in response to N-deficiency. Several AP2-EREBP family members involved in multiple hormone signaling pathways were among the DEGs. These transcription factors might play important roles in the rtcs-dependent regulatory network related to root development and the N-deficiency response. Genes encoding the nitrate transporters NRT2-1, NAR2.1, NAR2.2, and NAR2.3 showed much higher transcript levels in rtcs than in wild-type under normal-N conditions. This result indicated that the LBD gene family mainly functions as transcriptional repressors, as noted in other studies. In summary, using a comparative RNA-Seq-based approach

  17. Regional Innovation Clusters

    Data.gov (United States)

    Small Business Administration — The Regional Innovation Clusters serve a diverse group of sectors and geographies. Three of the initial pilot clusters, termed Advanced Defense Technology clusters,...

  18. Dynamically allocated virtual clustering management system

    Science.gov (United States)

    Marcus, Kelvin; Cannata, Jess

    2013-05-01

    The U.S Army Research Laboratory (ARL) has built a "Wireless Emulation Lab" to support research in wireless mobile networks. In our current experimentation environment, our researchers need the capability to run clusters of heterogeneous nodes to model emulated wireless tactical networks where each node could contain a different operating system, application set, and physical hardware. To complicate matters, most experiments require the researcher to have root privileges. Our previous solution of using a single shared cluster of statically deployed virtual machines did not sufficiently separate each user's experiment due to undesirable network crosstalk, thus only one experiment could be run at a time. In addition, the cluster did not make efficient use of our servers and physical networks. To address these concerns, we created the Dynamically Allocated Virtual Clustering management system (DAVC). This system leverages existing open-source software to create private clusters of nodes that are either virtual or physical machines. These clusters can be utilized for software development, experimentation, and integration with existing hardware and software. The system uses the Grid Engine job scheduler to efficiently allocate virtual machines to idle systems and networks. The system deploys stateless nodes via network booting. The system uses 802.1Q Virtual LANs (VLANs) to prevent experimentation crosstalk and to allow for complex, private networks eliminating the need to map each virtual machine to a specific switch port. The system monitors the health of the clusters and the underlying physical servers and it maintains cluster usage statistics for historical trends. Users can start private clusters of heterogeneous nodes with root privileges for the duration of the experiment. Users also control when to shutdown their clusters.

  19. Plant diversity effects on root decomposition in grasslands

    Science.gov (United States)

    Chen, Hongmei; Mommer, Liesje; van Ruijven, Jasper; de Kroon, Hans; Gessler, Arthur; Scherer-Lorenzen, Michael; Wirth, Christian; Weigelt, Alexandra

    2016-04-01

    Loss of plant diversity impairs ecosystem functioning. Compared to other well-studied processes, we know little about whether and how plant diversity affects root decomposition, which is limiting our knowledge on biodiversity-carbon cycling relationships in the soil. Plant diversity potentially affects root decomposition via two non-exclusive mechanisms: by providing roots of different substrate quality and/or by altering the soil decomposition environment. To disentangle these two mechanisms, three decomposition experiments using a litter-bag approach were conducted on experimental grassland plots differing in plant species richness, functional group richness and functional group composition (e.g. presence/absence of grasses, legumes, small herbs and tall herbs, the Jena Experiment). We studied: 1) root substrate quality effects by decomposing roots collected from the different experimental plant communities in one common plot; 2) soil decomposition environment effects by decomposing standard roots in all experimental plots; and 3) the overall plant diversity effects by decomposing community roots in their 'home' plots. Litter bags were installed in April 2014 and retrieved after 1, 2 and 4 months to determine the mass loss. We found that mass loss decreased with increasing plant species richness, but not with functional group richness in the three experiments. However, functional group presence significantly affected mass loss with primarily negative effects of the presence of grasses and positive effects of the presence of legumes and small herbs. Our results thus provide clear evidence that species richness has a strong negative effect on root decomposition via effects on both root substrate quality and soil decomposition environment. This negative plant diversity-root decomposition relationship may partly account for the positive effect of plant diversity on soil C stocks by reducing C loss in addition to increasing primary root productivity. However, to fully

  20. Root diseases, climate change and biomass productivity

    International Nuclear Information System (INIS)

    Tree growth and yield in eastern boreal spruce fir forests are both greatly affected by root and butt rots. These pests are also prevalent in western coniferous species and boreal-sub-boreal forests. Infections are difficult to detect, but reduced growth, tree mortality, wind throw and scaled butt cull contribute to considerable forest gaps. Harvesting and stand tending practices in second growth stands are creating conditions for increased incidence. Tree stress is one of the major factors affecting the spread of root disease. It is expected that climate change will create abnormal stress conditions that will further compound the incidence of root disease. A comparison was made between natural and managed stands, including harvesting and stand practices such as commercial thinning. Studies of Douglas-fir forests in British Columbia were presented, with results indicating that managed forests contain one third to one half less carbon biomass than unmanaged forests. It was concluded that root diseases must be recognized and taken into account in order to refine and improve biomass estimates, prevent overestimation of wood supply models and avoid potential wood fibre losses. 40 refs., 2 figs.

  1. Complex Roots of Quaternion Polynomials

    OpenAIRE

    Dospra, Petroula; Poulakis, Dimitrios

    2015-01-01

    The polynomials with quaternion coefficients have two kind of roots: isolated and spherical. A spherical root generates a class of roots which contains only one complex number $z$ and its conjugate $\\bar{z}$, and this class can be determined by $z$. In this paper, we deal with the complex roots of quaternion polynomials. More precisely, using B\\'{e}zout matrices, we give necessary and sufficient conditions, for a quaternion polynomial to have a complex root, a spherical root, and a complex is...

  2. Statistical modeling of nitrogen-dependent modulation of root system architecture in Arabidopsis thaliana

    Institute of Scientific and Technical Information of China (English)

    Takao Araya; Takuya Kubo; Nicolaus von Wiren; Hideki Takahashi

    2016-01-01

    Plant root development is strongly affected by nutrient availability. Despite the importance of structure and function of roots in nutrient acquisition, statistical modeling approaches to evaluate dynamic and temporal modulations of root system architecture in response to nutrient availability have remained as widely open and exploratory areas in root biology. In this study, we developed a statistical modeling approach to investigate modulations of root system archi-tecture in response to nitrogen availability. Mathematical models were designed for quantitative assessment of root growth and root branching phenotypes and their dynamic relationships based on hierarchical configuration of primary and lateral roots formulating the fishbone-shaped root system architecture in Arabidopsis thaliana. Time-series datasets reporting dynamic changes in root developmental traits on different nitrate or ammonium concentrations were gener-ated for statistical analyses. Regression analyses unraveled key parameters associated with:(i) inhibition of primary root growth under nitrogen limitation or on ammonium;(i ) rapid progression of lateral root emergence in response to ammonium; and (i i) inhibition of lateral root elongation in the presence of excess nitrate or ammonium. This study provides a statistical framework for interpreting dynamic modulation of root system architecture, supported by meta-analysis of datasets displaying morphological responses of roots to diverse nitrogen supplies.

  3. Effect of calmodulin antagonists on the growth and graviresponsiveness of primary roots of maize

    Science.gov (United States)

    Stinemetz, C. L.; Hasenstein, K. H.; Young, L. M.; Evans, M. L.

    1992-01-01

    We examined the effect of calmodulin (CaM) antagonists applied at the root tip on root growth, gravity-induced root curvature, and the movement of calcium across the root tip and auxin (IAA) across the elongation zone of gravistimulated roots. All of the CaM antagonists used in these studies delayed gravity-induced curvature at a concentration (1 micromole) that did not affect root growth. Calmodulin antagonists (> or = 1 micromole) inhibited downward transport of label from 45Ca2+ across the caps of gravistimulated roots relative to the downward transport of 45Ca2+ in gravistimulated roots which were not treated with CaM antagonists. Application of CaM antagonists at the root tip (> or = 1 micromole) also decreased the relative downward movement of label from 3H-IAA applied to the upper side of the elongation zone of gravistimulated roots. In general, tip application of antagonists inhibited neither the upward transport of 45Ca2+ in the root tip nor the upward movement of label from 3H-IAA in the elongation zone of gravistimulated roots. Thus, roots treated with CaM antagonists > or = 1 micromole become less graviresponsive and exhibit reduced or even a reversal of downward polarity of calcium transport across the root tip and IAA transport across the elongation zone. The results indicate that calmodulin-regulated events play a role in root gravitropism.

  4. Auxin, the organizer of the hormonal/environmental signals for root hair growth

    OpenAIRE

    Lee, Richard D.-W.; Cho, Hyung-Taeg

    2013-01-01

    The root hair development is controlled by diverse factors such as fate-determining developmental cues, auxin-related environmental factors, and hormones. In particular, the soil environmental factors are important as they maximize their absorption by modulating root hair development. These environmental factors affect the root hair developmental process by making use of diverse hormones. These hormonal factors interact with each other to modulate root hair development in which auxin appears ...

  5. Root responses of grassland species to spatial heterogeneity of plant-soil feedback

    OpenAIRE

    Hendriks, Marloes; Visser, Eric J. W.; Visschers, Isabella G. S.; Aarts, Bart H. J.; de Caluwe, Hannie; Smit-Tiekstra, Annemiek E.; van der Putten, Wim H.; de Kroon, Hans; MOMMER, LIESJE

    2015-01-01

    Plant roots selectively forage for soil nutrients when these are heterogeneously distributed. In turn, effects of plant roots on biotic and abiotic conditions in the soil, which result in so-called plant–soil feedback can be heterogeneously distributed as well, but it is unknown how this heterogeneity affects root distribution, nutrient uptake and plant biomass production. Here, we investigate plant root distribution patterns as influenced by spatial heterogeneity of plant–soil feedback in so...

  6. Soil Influences Colonization of Root-Associated Fungal Endophyte Communities of Maize, Wheat, and Their Progenitors

    OpenAIRE

    Deepak Bokati; José Herrera; Ravin Poudel

    2016-01-01

    Root-associated fungal endophytes are vital component of root microbiome as some mitigate their host’s abiotic and biotic stress. We characterized root-associated fungal endophytes in cereal grains and their progenitors grown on two different soil-types. We aimed at determining how clay and desert soil affects the colonization of root fungal community. Both culture-dependent and culture-independent methods were employed to identify endophytes that successfully colonized greenhouse-grown host ...

  7. Clustering experiments

    CERN Document Server

    Wang, Zhengwei; Tan, Ken; Di, Zengru; Roehner, Bertrand M

    2011-01-01

    It is well known that bees cluster together in cold weather, in the process of swarming (when the ``old'' queen leaves with part of the colony) or absconding (when the queen leaves with all the colony) and in defense against intruders such as wasps or hornets. In this paper we describe a fairly different clustering process which occurs at any temperature and independently of any special stimulus or circumstance. As a matter of fact, this process is about four times faster at 28 degree Celsius than at 15 degrees. Because of its simplicity and low level of ``noise'' we think that this phenomenon can provide a means for exploring the strength of inter-individual attraction between bees or other living organisms. For instance, and at first sight fairly surprisingly, our observations showed that this attraction does also exist between bees belonging to different colonies. As this study is aimed at providing a comparative perspective, we also describe a similar clustering experiment for red fire ants.

  8. Root canal medicaments.

    Science.gov (United States)

    Kawashima, Nobuyuki; Wadachi, Reiko; Suda, Hideaki; Yeng, Thai; Parashos, Peter

    2009-02-01

    The ultimate goals of endodontic treatment are complete removal of bacteria, their byproducts and pulpal remnants from infected root canals and the complete seal of disinfected root canals. Intracanal medicaments have been thought an essential step in killing the bacteria in root canals; however, in modern endodontics, shaping and cleaning may be assuming greater importance than intracanal medicaments as a means of disinfecting root canals. Until recently, formocresol and its relatives were frequently used as intracanal medicaments, but it was pointed out that such bactericidal chemicals dressed in the canal distributed to the whole body from the root apex and so might induce various harmful effects including allergies. Furthermore, as these medicaments are potent carcinogenic agents, there is no indication for these chemicals in modern endodontic treatment. Today, biocompatibility and stability are essential properties for intracanal medicaments. The more modern meaning of intracanal dressing is for a blockade against coronal leakage from the gap between filling materials and cavity wall. Calcium hydroxide has been determined as suitable for use as an intracanal medicament as it is stable for long periods, harmless to the body, and bactericidal in a limited area. It also induces hard tissue formation and is effective for stopping inflammatory exudates. Single-visit endodontics, where intracanal medicaments are not used, is generally not now contraindicated and various reports have shown that the clinical outcomes between single- and multiple- visit endodontics are similar. There is no reason to counsel against single-visit endodontics: however, if multiple-visit endodontics is chosen, calcium hydroxide is recommended to be used as an intracanal medicament. PMID:19323305

  9. Hairy roots are more sensitive to auxin than normal roots

    OpenAIRE

    Shen, Wen Hui; Petit, Annik; Guern, Jean; Tempé, Jacques

    1988-01-01

    Responses to auxin of Lotus corniculatus root tips or protoplasts transformed by Agrobacterium rhizogenes strains 15834 and 8196 were compared to those of their normal counterparts. Three different types of experiments were performed, involving long-term, medium-term, or short-term responses to a synthetic auxin, 1-naphthaleneacetic acid. Root tip elongation, proton excretion by root tips, and transmembrane electrical potential difference of root protoplasts were measured as a function of exo...

  10. Factor PD-Clustering

    OpenAIRE

    Gettler Summa, Mireille; Palumbo, Francesco; Tortora, Cristina

    2012-01-01

    Factorial clustering methods have been developed in recent years thanks to the improving of computational power. These methods perform a linear transformation of data and a clustering on transformed data optimizing a common criterion. Factorial PD-clustering is based on Probabilistic Distance clustering (PD-clustering). PD-clustering is an iterative, distribution free, probabilistic, clustering method. Factor PD-clustering make a linear transformation of original variables into a reduced numb...

  11. Characteristic of Small Scale Food Industry Cluster in West Sumatera

    OpenAIRE

    Gunarif Taib; Santosa Santosa; Masrul Djalal; Helmi Helmi

    2014-01-01

    Clusters of small-scale food industries have different characteristics with industrial cluster in general. These characteristics need to know to develop a plan for cluster development. This study was conducted to determine charasteristics clusters of small-scale food industry, especially in West Sumatra. For the analysis of the components of industrial and technological components that affect the development of small-scale food industry cluster in West Sumatra. All variables influence the lev...

  12. Modified K-Means for Better Initial Cluster Centres

    OpenAIRE

    Kalpana D. Joshi; P.S. Nalwade

    2013-01-01

    The k-means clustering algorithm is most popularly used in data mining for real worldapplications. The efficiency and performance of the k-means algorithm is greatly affected by initial clustercenters as different initial cluster centers often lead to different clustering. In this paper, we propose amodified k-means algorithm which has additional steps for selecting better cluster centers. We compute Minand Max distance for every cluster and find high density objects for selection of better k.

  13. Second generation stellar disks in Globular Clusters and cluster ellipticities

    CERN Document Server

    Mastrobuono-Battisti, Alessandra

    2015-01-01

    Globular clusters (GCs) and Nuclear Stellar Clusters (NSCs) are typically composed by several stellar generations, characterized by different ages and chemical compositions. The youngest populations in NSCs appear to reside in disk-like structures, as observed in our Galaxy and in M31. Gas infall followed by formation of second generation (SG) stars in GCs may similarly form disk-like structures in the clusters nuclei. Here we explore this possibility and follow the long term evolution of stellar disks embedded in GCs, and study their affects on the evolution of the clusters. We study disks with different masses by means of detailed N-body simulations and explore their morphological and kinematic signatures on the GC structures. We find that as a second generation disk relaxes, the old, first generation, stellar population flattens and becomes more radially anisotropic, making the GC structure become more elliptical. The second generation stellar population is characterized by a lower velocity dispersion, and...

  14. Cytokinin-induced promotion of root meristem size in the fern Azolla supports a shoot-like origin of euphyllophyte roots.

    Science.gov (United States)

    de Vries, Jan; Fischer, Angela Melanie; Roettger, Mayo; Rommel, Sophie; Schluepmann, Henriette; Bräutigam, Andrea; Carlsbecker, Annelie; Gould, Sven Bernhard

    2016-01-01

    The phytohormones cytokinin and auxin orchestrate the root meristem development in angiosperms by determining embryonic bipolarity. Ferns, having the most basal euphyllophyte root, form neither bipolar embryos nor permanent embryonic primary roots but rather an adventitious root system. This raises the questions of how auxin and cytokinin govern fern root system architecture and whether this can tell us something about the origin of that root. Using Azolla filiculoides, we characterized the influence of IAA and zeatin on adventitious fern root meristems and vasculature by Nomarski microscopy. Simultaneously, RNAseq analyses, yielding 36,091 contigs, were used to uncover how the phytohormones affect root tip gene expression. We show that auxin restricts Azolla root meristem development, while cytokinin promotes it; it is the opposite effect of what is observed in Arabidopsis. Global gene expression profiling uncovered 145 genes significantly regulated by cytokinin or auxin, including cell wall modulators, cell division regulators and lateral root formation coordinators. Our data illuminate both evolution and development of fern roots. Promotion of meristem size through cytokinin supports the idea that root meristems of euphyllophytes evolved from shoot meristems. The foundation of these roots was laid in a postembryonically branching shoot system. PMID:26358624

  15. Variation in root wood anatomy

    NARCIS (Netherlands)

    Cutler, D.F.

    1976-01-01

    Variability in the anatomy of root wood of selected specimens particularly Fraxinus excelsior L. and Acer pseudoplatanus L. in the Kew reference microscope slide collection is discussed in relation to generalised statements in the literature on root wood anatomy.

  16. The Physiology of Adventitious Roots.

    Science.gov (United States)

    Steffens, Bianka; Rasmussen, Amanda

    2016-02-01

    Adventitious roots are plant roots that form from any nonroot tissue and are produced both during normal development (crown roots on cereals and nodal roots on strawberry [Fragaria spp.]) and in response to stress conditions, such as flooding, nutrient deprivation, and wounding. They are important economically (for cuttings and food production), ecologically (environmental stress response), and for human existence (food production). To improve sustainable food production under environmentally extreme conditions, it is important to understand the adventitious root development of crops both in normal and stressed conditions. Therefore, understanding the regulation and physiology of adventitious root formation is critical for breeding programs. Recent work shows that different adventitious root types are regulated differently, and here, we propose clear definitions of these classes. We use three case studies to summarize the physiology of adventitious root development in response to flooding (case study 1), nutrient deficiency (case study 2), and wounding (case study 3). PMID:26697895

  17. Classification of Different Species Families using Clustering Algorithm

    Directory of Open Access Journals (Sweden)

    D.Chandravathi

    2010-08-01

    Full Text Available The division of similar objects into groups is known as Clustering. The main objective of this implementation is classification of DNA sequences related to different species and their families using Clustering Algorithm- Leader-sub leader algorithm. Clustering is done with the help of threshold value of scoring matrix. It is another simple and efficient technique that may help to find family, uperfamily and sub-family by generating sub clusters. From thisanalysis there may be a chance that members in sub-cluster may be affected if one of the leader clusters gets affected.

  18. Artificial Root Exudate System (ARES): a field approach to simulate tree root exudation in soils

    Science.gov (United States)

    Lopez-Sangil, Luis; Estradera-Gumbau, Eduard; George, Charles; Sayer, Emma

    2016-04-01

    The exudation of labile solutes by fine roots represents an important strategy for plants to promote soil nutrient availability in terrestrial ecosystems. Compounds exuded by roots (mainly sugars, carboxylic and amino acids) provide energy to soil microbes, thus priming the mineralization of soil organic matter (SOM) and the consequent release of inorganic nutrients into the rhizosphere. Studies in several forest ecosystems suggest that tree root exudates represent 1 to 10% of the total photoassimilated C, with exudation rates increasing markedly under elevated CO2 scenarios. Despite their importance in ecosystem functioning, we know little about how tree root exudation affect soil carbon dynamics in situ. This is mainly because there has been no viable method to experimentally control inputs of root exudates at field scale. Here, I present a method to apply artificial root exudates below the soil surface in small field plots. The artificial root exudate system (ARES) consists of a water container with a mixture of labile carbon solutes (mimicking tree root exudate rates and composition), which feeds a system of drip-tips covering an area of 1 m2. The tips are evenly distributed every 20 cm and inserted 4-cm into the soil with minimal disturbance. The system is regulated by a mechanical timer, such that artificial root exudate solution can be applied at frequent, regular daily intervals. We tested ARES from April to September 2015 (growing season) within a leaf-litter manipulation experiment ongoing in temperate deciduous woodland in the UK. Soil respiration was measured monthly, and soil samples were taken at the end of the growing season for PLFA, enzymatic activity and nutrient analyses. First results show a very rapid mineralization of the root exudate compounds and, interestingly, long-term increases in SOM respiration, with negligible effects on soil moisture levels. Large positive priming effects (2.5-fold increase in soil respiration during the growing

  19. Root canal retained restorations: 3. Root-face attachments.

    Science.gov (United States)

    Dummer, P M; Edmunds, D H; Gidden, J R

    1990-10-01

    It has been common practice for many years to use retained roots to provide support and stability for partial or full dentures. The retention of such overdentures is greatly enhanced if the remaining roots are modified and restored with posts and root-face attachments. The final article in this series on root canal retained restorations classifies and describes some of the root-face attachments currently available, and also describes a number of prefabricated post systems with integral overdenture attachments. Guidelines for clinical and laboratory procedures are given. PMID:2097234

  20. Hairy roots are more sensitive to auxin than normal roots.

    Science.gov (United States)

    Shen, W H; Petit, A; Guern, J; Tempé, J

    1988-05-01

    Responses to auxin of Lotus corniculatus root tips or protoplasts transformed by Agrobacterium rhizogenes strains 15834 and 8196 were compared to those of their normal counterparts. Three different types of experiments were performed, involving long-term, medium-term, or short-term responses to a synthetic auxin, 1-naphthaleneacetic acid. Root tip elongation, proton excretion by root tips, and transmembrane electrical potential difference of root protoplasts were measured as a function of exogenous auxin concentration. The sensitivity of hairy root tips or protoplasts to exogenous auxin was found to be 100-1000 times higher than that of untransformed material. PMID:16593928

  1. Negative phototropism of rice root

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    @@It is often believed that the stem of higher plants has characteristics of positive phototropism, and the root shows no phototropism or no sensitivity to light though the root of Arabdopsis was reported possessing characteristics of negative phototropism. In this study, a distinct negative phototropism of the root system of rice seedlings was observed.

  2. Diagravitropism in corn roots

    Science.gov (United States)

    Leopold, A. C.; Wettlaufer, S. H.

    1988-01-01

    The diagravitropic behavior of Merit corn (Zea mays L.) roots grown in darkness provides an opportunity for comparison of two qualitatively different gravitropic systems. As with positive gravitropism, diagravitropism is shown to require the presence of the root cap, have a similar time course for the onset of curvature, and a similar presentation time. In contrast with positive gravitropism, diagravitropism appears to have a more limited requirement for calcium, for it is insensitive to the elution of calcium by EGTA and insensitive to the subsequent addition of a calcium/EGTA complex. These results are interpreted as indicating that whereas the same sensing system is shared by the two types of gravitropism, separate transductive systems are involved, one for diagravitropism, which is relatively independent of calcium, and one for positive gravitropism, which is markedly dependent on calcium.

  3. Cluster-based global firms' use of local capabilities

    DEFF Research Database (Denmark)

    Andersen, Poul Houman; Bøllingtoft, Anne

    2011-01-01

    three clusters strongly affected by increasing global division of labour. Findings – The paper suggests that globalization has affected how firms use local resources and combine local and global knowledge. Unexpectedly, clustered firms with explicit procedures and established global fora for exchanging...... developed countries. Originality/value – Several studies have examined the changing role of clusters in the evolving global division of labour. However, research is lacking that addresses the challenges of transformation from the level of the CBF and how these may be affected by cluster evolution. The paper...... takes a micro-oriented perspective and focus on clusters in Denmark, a small and mature economy...

  4. Stellar Encounter Rate in Galactic Globular Clusters

    CERN Document Server

    Bahramian, Arash; Sivakoff, Gregory R; Gladstone, Jeanette C

    2013-01-01

    The high stellar densities in the cores of globular clusters cause significant stellar interactions. These stellar interactions can produce close binary mass-transferring systems involving compact objects and their progeny, such as X-ray binaries and radio millisecond pulsars. Comparing the numbers of these systems and interaction rates in different clusters drives our understanding of how cluster parameters affect the production of close binaries. In this paper we estimate stellar encounter rates (Gamma) for 124 Galactic globular clusters based on observational data as opposed to the methods previously employed, which assumed "King-model" profiles for all clusters. By deprojecting cluster surface brightness profiles to estimate luminosity density profiles, we treat "King-model" and "core-collapsed" clusters in the same way. In addition, we use Monte-Carlo simulations to investigate the effects of uncertainties in various observational parameters (distance, reddening, surface brightness) on Gamma, producing t...

  5. Factors influencing the future need for treatment of root surfaces.

    Science.gov (United States)

    Ettinger, R L; Hand, J S

    1994-10-01

    This paper discusses the current status of root surface caries in the elderly population and the need for treatment of this condition in the future. Although root surface exposure and root caries have been reported for adults at all ages, the people at greatest risk for these conditions are the elderly. In the United States, life expectancy and the population aged 65 years and older has increased substantially, and the proportion of the elderly population who are dentate has increased and is projected to increase further. Utilization of dental services by the elderly is similar to that of employed adults. Interpretation of studies of the prevalence and incidence of root surface caries are difficult due to differences in sampling, definition of lesions, and reporting conventions. Root surface caries prevalence is related to age and continues to be a significant problem for this population as they age. Factors that may affect the future need for treatment are explored. PMID:7986448

  6. Cluster automorphisms and compatibility of cluster variables

    OpenAIRE

    Assem, Ibrahim; Schiffler, Ralf; Shramchenko, Vasilisa

    2013-01-01

    In this paper, we introduce a notion of unistructural cluster algebras, for which the set of cluster variables uniquely determines the clusters. We prove that cluster algebras of Dynkin type and cluster algebras of rank 2 are unistructural, then prove that if $\\mathcal{A}$ is unistructural or of Euclidean type, then $f: \\mathcal{A}\\to \\mathcal{A}$ is a cluster automorphism if and only if $f$ is an automorphism of the ambient field which restricts to a permutation of the cluster variables. In ...

  7. Mental Roots of Terror

    OpenAIRE

    Saruhan, Müfit Selim

    2004-01-01

    In this article, I deal with mental and terror relationship. Mental roots of terror are being examined. Religion has nothing to do with terrorism. Terrorist tries to misuse religion. Mental with prejudice and lack of knowledge occupies the personality of individual and his ability to judge. Purification of mind from any external and internal prejudices is the unique solution of terrorism. Only within extensive education we can overcome terrorism. Terrorism could not apply to a religion or a n...

  8. Rooted in Movement

    DEFF Research Database (Denmark)

    The result of the synergy between four doctoral projects and an advanced MA-level course on Bronze Age Europe, this integrated assemblage of articles represents a variety of different subjects united by a single theme: movement. Ranging from theoretical discussion of the various responses to and ...... period of European prehistory. In so doing, the text not only addresses transmission and reception, but also the conceptualization of mobility within a world which was literally Rooted in Movement....

  9. Roots of Financial Literacy

    OpenAIRE

    Grohmann, Antonia; Kouwenberg, Roy; Menkhoff, Lukas

    2014-01-01

    Our study aims to uncover the roots of financial literacy. Better financial literacy predicts more informed savings and borrowing decisions in our sample, covering the urban middle-class in an emerging economy. We then test education at school, family background, parental teaching, and childhood experiences with money as potential determinants of financial literacy. In addition to risk tolerance and having basic numeracy skills, we find that family variables matter most, in particular better ...

  10. Globular Cluster Formation in the Virgo Cluster

    CERN Document Server

    Moran, C Corbett; Lake, G

    2014-01-01

    Metal poor globular clusters (MPGCs) are a unique probe of the early universe, in particular the reionization era. Systems of globular clusters in galaxy clusters are particularly interesting as it is in the progenitors of galaxy clusters that the earliest reionizing sources first formed. Although the exact physical origin of globular clusters is still debated, it is generally admitted that globular clusters form in early, rare dark matter peaks (Moore et al. 2006; Boley et al. 2009). We provide a fully numerical analysis of the Virgo cluster globular cluster system by identifying the present day globular cluster system with exactly such early, rare dark matter peaks. A popular hypothesis is that that the observed truncation of blue metal poor globular cluster formation is due to reionization (Spitler et al. 2012; Boley et al. 2009; Brodie & Strader 2006); adopting this view, constraining the formation epoch of MPGCs provides a complementary constraint on the epoch of reionization. By analyzing both the l...

  11. Proteome changes induced by aluminum stress in tomato roots

    Science.gov (United States)

    Growth inhibition in acid soils due to Al stress affects crop production worldwide. To understand mechanisms in sensitive crops that are affected by Al stress, a proteomic analysis of primary tomato root tissue, grown in Alamended and non-amended liquid cultures, was performed. DIGE-SDS-MALDI-TOF-TO...

  12. Unravelling signalling circuits regulating tomato root development using induced mutations

    International Nuclear Information System (INIS)

    Plant roots performs multitude of functions such as water, nutrient uptake and anchorage to the soil. The performance of root to carry these functions can be improved by selecting for induced mutants affected in root development and differentiation. We used tomato as a model plant to decipher the mechanisms underlying root differentiation. We screened EMS and γ-radiated tomato M2 seedlings for mutants defective in root development. In this study, we describe unraveling of signaling circuits regulating root development in tomato. We made detailed physiological, genetic and biochemical characterization of tomato root mutants that are affected in nitric oxide (NO) production and auxin transport. It is now recognized that NO is an important gas molecule that has functions and roles in plants comparable to other gaseous plant hormone ethylene. NO has been reported to participate in many physiological phenomena: such as seed germination, resistance to plant pathogens, stomatal movements, and flowering. Although NO plays a paramount role in plant development, little information is available about mechanisms regulating its biosynthesis in plants. We isolated a tomato mutant displaying extremely short root (shr) in seedlings. We observed that in tomato shr mutant overproduction of NO caused shortening of root. We used shr root elongation as a bioassay to analyze signaling pathway regulating NO formation in plants. We show that a pathway very similar to a mammalian signaling pathway regulates NO levels in plants. The transport of auxin in plants involves a very complex network comprising of proteins, which bring the hormone in and out of the cells. The polycotyledon (poc) mutant of tomato shows an enhanced polar transport of auxin (PAT). Analysis of the role of auxin transporters in poc mutant, especially PIN1, responsible for PAT, at the cellular level would be presented (author)

  13. Aconitum Alkaloid Poisoning Related to the Culinary Uses of Aconite Roots

    Directory of Open Access Journals (Sweden)

    Thomas Y. K. Chan

    2014-09-01

    Full Text Available Aconite roots (roots or root tubers of the Aconitum species are eaten as root vegetables and used to prepare herbal soups and meals, mainly for their purported health benefits. Aconite roots contain aconitine and other Aconitum alkaloids, which are well known cardiotoxins and neurotoxins. To better understand why Aconitum alkaloid poisoning related to the culinary uses of aconite roots can occur and characterize the risks posed by these “food supplements”, relevant published reports were reviewed. From 1995 to 2013, there were eight reports of aconite poisoning after consumption of these herbal soups and meals, including two reports of large clusters of cases (n = 19–45 and two reports of cases (n = 15–156 managed by two hospitals over a period of 4.5 to 5 years. The herbal formulae used did not adhere to the suggested guidelines, with regarding to the doses (50–500 g instead of 3–30 g per person and types (raw instead of processed of aconite roots used. The quantities of Aconitum alkaloids involved were huge, taking into consideration the doses of aconite roots used to prepare herbal soups/meals and the amounts of aconite roots and herbal soups/meals consumed. In a large cluster of cases, despite simmering raw “caowu” (the root tuber of A. kusnezoffii in pork broth for 24 h, all 19 family members who consumed this soup and boiled “caowu” developed poisoning. Severe or even fatal aconite poisoning can occur after consumption of herbal soups and foods prepared from aconite roots. Even prolonged boiling may not be protective if raw preparations and large quantities of aconite roots are used. The public should be warned of the risk of severe poisoning related to the culinary and traditional medicinal uses of aconite roots.

  14. Do roots mind the gap?

    OpenAIRE

    A. Carminati; Vetterlein, D; Koebernick, N.; Blaser, S; Weller, U; Vogel, H.-J.

    2012-01-01

    Roots need to be in good contact with the soil to take up water and nutrients. However, when the soil dries and roots shrink, air-filled gaps form at the root-soil interface. Do gaps actually limit the root water uptake, or do they form after water flow in soil is already limiting?Four white lupins were grown in cylinders of 20 cm height and 8 cm diameter. The dynamics of root and soil structure were recorded using X-ray CT at regular intervals during one drying/wetting cycle. Tensiometers we...

  15. Cluster formation in low-density condition

    International Nuclear Information System (INIS)

    We study cluster formation in low-density condition by using antisymmetrized molecular dynamics (AMD). We use the frictional cooling method constraining a root-mean-square radius to make low-density situation. We apply this method to 40Ca, 44Ca and 48Ca. We find that α cluster is the basic unit in any low density situation for 40Ca which is saturated by spin and isospin, and that the magic number n=8 plays an important role in cluster formation in low density situation in common with these three nuclei, and that the 14C cluster appears in case of 44Ca and 48Ca due to the neutron-rich property, and so on. (author)

  16. Adaptive Evolutionary Clustering

    OpenAIRE

    Xu, Kevin S.; Kliger, Mark; Hero III, Alfred O.

    2011-01-01

    In many practical applications of clustering, the objects to be clustered evolve over time, and a clustering result is desired at each time step. In such applications, evolutionary clustering typically outperforms traditional static clustering by producing clustering results that reflect long-term trends while being robust to short-term variations. Several evolutionary clustering algorithms have recently been proposed, often by adding a temporal smoothness penalty to the cost function of a st...

  17. Relational visual cluster validity

    OpenAIRE

    Ding, Y.; Harrison, R F

    2007-01-01

    The assessment of cluster validity plays a very important role in cluster analysis. Most commonly used cluster validity methods are based on statistical hypothesis testing or finding the best clustering scheme by computing a number of different cluster validity indices. A number of visual methods of cluster validity have been produced to display directly the validity of clusters by mapping data into two- or three-dimensional space. However, these methods may lose too much information to corre...

  18. [An analysis of key points for root canal therapy technique].

    Science.gov (United States)

    Fan, M W

    2016-08-01

    The success rate of root canal therapy(RCT)have been improved continuously along with the advancement in RCT techniques in the past several decades. If standard procedures of modern RCT techniques are strictly followed, the success rate of RCT may exceed 90%. The success of RCT is mainly affected by such factors as clear concept of the anatomy of root canals, proper mechanical and chemical preparation and perfect filling of root canal system. If these factors are sufficiently noted, a success is easy to achieve. Even though the primary RCT fails, retreatment can further be conducted to save the diseased teeth. PMID:27511032

  19. Frequency of the external resorptions of root apex

    OpenAIRE

    Opačić-Galić Vanja; Živković Slavoljub

    2004-01-01

    Root resorptions present a significant problem in endodontic therapy of the affected teeth and in dentistry in general. The objective of this study was to analyze, based on epidemiological and statistical research, the frequency of clinical incidence of pathological root resorptions in everyday practice related to localization, type of tooth, age and sex of patients. Radiographie documentation of patients treated from 1997 till 2002 at the Department of Conservative Dentistry and Endodontics,...

  20. Dynamical evolution of globular-cluster systems in clusters of galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Muzzio, J.C.

    1987-04-01

    The dynamical processes that affect globular-cluster systems in clusters of galaxies are analyzed. Two-body and impulsive approximations are utilized to study dynamical friction, drag force, tidal stripping, tidal radii, globular-cluster swapping, tidal accretion, and galactic cannibalism. The evolution of galaxies and the collision of galaxies are simulated numerically; the steps involved in the simulation are described. The simulated data are compared with observations. Consideration is given to the number of galaxies, halo extension, location of the galaxies, distribution of the missing mass, nonequilibrium initial conditions, mass dependence, massive central galaxies, globular-cluster distribution, and lost globular clusters. 116 references.

  1. The Importance of Juvenile Root Traits for Crop Yields

    Science.gov (United States)

    White, Philip; Adu, Michael; Broadley, Martin; Brown, Lawrie; Dupuy, Lionel; George, Timothy; Graham, Neil; Hammond, John; Hayden, Rory; Neugebauer, Konrad; Nightingale, Mark; Ramsay, Gavin; Thomas, Catherine; Thompson, Jacqueline; Wishart, Jane; Wright, Gladys

    2014-05-01

    Genetic variation in root system architecture (RSA) is an under-exploited breeding resource. This is partly a consequence of difficulties in the rapid and accurate assessment of subterranean root systems. However, although the characterisation of root systems of large plants in the field are both time-consuming and labour-intensive, high-throughput (HTP) screens of root systems of juvenile plants can be performed in the field, glasshouse or laboratory. It is hypothesised that improving the root systems of juvenile plants can accelerate access to water and essential mineral elements, leading to rapid crop establishment and, consequently, greater yields. This presentation will illustrate how aspects of the juvenile root systems of potato (Solanum tuberosum L.) and oilseed rape (OSR; Brassica napus L.) correlate with crop yields and examine the reasons for such correlations. It will first describe the significant positive relationships between early root system development, phosphorus acquisition, canopy establishment and eventual yield among potato genotypes. It will report the development of a glasshouse assay for root system architecture (RSA) of juvenile potato plants, the correlations between root system architectures measured in the glasshouse and field, and the relationships between aspects of the juvenile root system and crop yields under drought conditions. It will then describe the development of HTP systems for assaying RSA of OSR seedlings, the identification of genetic loci affecting RSA in OSR, the development of mathematical models describing resource acquisition by OSR, and the correlations between root traits recorded in the HTP systems and yields of OSR in the field.

  2. Improvement of adventitious root formation in flax using hydrogen peroxide.

    Science.gov (United States)

    Takáč, Tomáš; Obert, Bohuš; Rolčík, Jakub; Šamaj, Jozef

    2016-09-25

    Flax (Linum usitatissimum L.) is an important crop for the production of oil and fiber. In vitro manipulations of flax are used for genetic improvement and breeding while improvements in adventitious root formation are important for biotechnological programs focused on regeneration and vegetative propagation of genetically valuable plant material. Additionally, flax hypocotyl segments possess outstanding morphogenetic capacity, thus providing a useful model for the investigation of flax developmental processes. Here, we investigated the crosstalk between hydrogen peroxide and auxin with respect to reprogramming flax hypocotyl cells for root morphogenetic development. Exogenous auxin induced the robust formation of adventitious roots from flax hypocotyl segments while the addition of hydrogen peroxide further enhanced this process. The levels of endogenous auxin (indole-3-acetic acid; IAA) were positively correlated with increased root formation in response to exogenous auxin (1-Naphthaleneacetic acid; NAA). Histochemical staining of the hypocotyl segments revealed that hydrogen peroxide and peroxidase, but not superoxide, were positively correlated with root formation. Measurements of antioxidant enzyme activities showed that endogenous levels of hydrogen peroxide were controlled by peroxidases during root formation from hypocotyl segments. In conclusion, hydrogen peroxide positively affected flax adventitious root formation by regulating the endogenous auxin levels. Consequently, this agent can be applied to increase flax regeneration capacity for biotechnological purposes such as improved plant rooting. PMID:26921706

  3. Mist, substrate water potential and cutting water potential influence rooting of stem cuttings of loblolly pine.

    Science.gov (United States)

    Lebude, Anthony V; Goldfarb, Barry; Blazich, Frank A; Wise, Farrell C; Frampton, John

    2004-07-01

    We investigated the influence of cutting water potential (Psicut) on rooting of juvenile hardwood (dormant) and softwood (succulent) stem cuttings of loblolly pine (Pinus taeda L.) propagated under varying substrate water potentials (Psisub) and volumes of mist application. Mist treatment and Psisub contributed to the Psicut of unrooted stem cuttings. When Psisub was held constant across mist treatments, mist treatment contributed strongly to Psicut. Substrate water potential affected rooting percentage when mist treatment was sub-optimal or excessive, otherwise mist treatment had a stronger effect than Psisub on rooting percentage. Cuttings rooted best when subjected to moderate cutting water potentials (-0.5 to -1.2 MPa) during the initial 4 or 5 weeks of the rooting period. Cuttings experiencing either severe water deficit or no water deficit rooted poorly. We conclude that the rooting environment should impose a moderate water stress on loblolly pine stem cuttings to achieve optimum rooting. PMID:15123454

  4. Nonsurgical Endodontic Retreatment of Advanced Inflammatory External Root Resorption Using Mineral Trioxide Aggregate Obturation

    Directory of Open Access Journals (Sweden)

    Shivani Utneja

    2012-01-01

    Full Text Available Inflammatory external root resorption is one of the major complications after traumatic dental injury. In this case report, we describe treatment of a maxillary central incisor affected by severe, perforating external root resorption. An 18-year-old patient presented with a previously traumatized, root-filled maxillary central incisor associated with pain and sinus tract. Radiographic examination revealed periradicular lesion involving pathologic resorption of the apical region of the root and lateral root surface both mesially and distally. After removal of the root canal filling, the tooth was disinfected with intracanal triple antibiotic paste for 2 weeks. The antibiotic dressing was then removed, and the entire root canal was filled with mineral trioxide aggregate. The endodontic access cavity was restored with composite resin. After 18 months, significant osseous healing of the periradicular region and lateral periodontium had occurred with arrest of external root resorption, and no clinical symptoms were apparent.

  5. Oil Palm (Elaeis guineensis Roots Response to Mechanization in Bernam Series Soil

    Directory of Open Access Journals (Sweden)

    Zuraidah Yahya

    2010-01-01

    Full Text Available Problem statement: Field practices involving the use of mechanization in oil palm plantations could result in soil compaction which alters the soil physical properties. The gradual deterioration of soil physical conditions could restrict the growth and function of roots. This study was carried out to evaluate the response of oil palm roots to changes in soil physical properties due to mechanization in Bernam series soil belonging to the clay texture class. Approach: Compaction treatments were imposed for 6 consecutive years and a comparison was done on the effects of different trailer weights on oil palm roots growth. Roots and soil were sampled using root and soil augers at 0-30 cm depth from the harvesting and frond pile paths. Results: The results showed that the oil palm roots were affected by the mechanization treatments. Growth of oil palm roots was significantly affected by the 4T trailer weight. Palms in compacted soil produced less primary and secondary roots but this was compensated for by the production of longer and thicker tertiary and quaternary roots. Conclusion: The compaction treatments affect the soil physical properties, which in turn affect the growth and distribution of oil palm roots.

  6. Characteristic of root decomposition in a tropical rainforest in Sarawak, Malaysi

    Science.gov (United States)

    Ohashi, Mizue; Makita, Naoki; Katayam, Ayumi; Kume, Tomonori; Matsumoto, Kazuho; Khoon Kho, L.

    2016-04-01

    Woody roots play a significant role in forest carbon cycling, as up to 60 percent of tree photosynthetic production can be allocated to belowground. Root decay is one of the main processes of soil C dynamics and potentially relates to soil C sequestration. However, much less attention has been paid for root litter decomposition compared to the studies of leaf litter because roots are hidden from view. Previous studies have revealed that physico-chemical quality of roots, climate, and soil organisms affect root decomposition significantly. However, patterns and mechanisms of root decomposition are still poorly understood because of the high variability of root properties, field environment and potential decomposers. For example, root size would be a factor controlling decomposition rates, but general understanding of the difference between coarse and fine root decompositions is still lacking. Also, it is known that root decomposition is performed by soil animals, fungi and bacteria, but their relative importance is poorly understood. In this study, therefore, we aimed to characterize the root decomposition in a tropical rainforest in Sarawak, Malaysia, and clarify the impact of soil living organisms and root sizes on root litter decomposition. We buried soil cores with fine and coarse root litter bags in soil in Lambir Hills National Park. Three different types of soil cores that are covered by 1.5 cm plastic mesh, root-impermeable sheet (50um) and fungi-impermeable sheet (1um) were prepared. The soil cores were buried in February 2013 and collected 4 times, 134 days, 226 days, 786 days and 1151 days after the installation. We found that nearly 80 percent of the coarse root litter was decomposed after two years, whereas only 60 percent of the fine root litter was decomposed. Our results also showed significantly different ratio of decomposition between different cores, suggesting the different contribution of soil living organisms to decomposition process.

  7. Root Ecological Niche Index and Root Distribution Characteristics of Artificial Phytocommunities in Rehabilitated Fields

    Institute of Scientific and Technical Information of China (English)

    Hu Jianzhong; Zhen Jiali; Shen Jingyu

    2006-01-01

    In the implementation phase of the Conversion of Cropland to Forest and Grassland (CCFG) project in China,it is important,from a scientific point of view,to recognize phytocommunities' characteristics,species compatibility,and ecological function.The ecological niche that roots occupy,their abundance and distribution,and the factors that affect them must be acknowledged.Following the methodology of community ecology,the total root mass of a phytocommunity is measured as cubic volume.Root biomass,length,and the number of roots in every diameter class,for each soil layer and for each plant species,are regarded as observation variables.In the first instance therefore,a new method to calculate the root ecological niche index (REND is proposed,embracing the entire phytocommunity of plantations.Using the new method,the roots of pbytocommunities in Datong County,Qinghai Province (one of the counties selected for the national CCFG experiment),are dealt with in this paper.The results show that most of the vertical distributions of plant roots belong to the type wherein the roots are concentrated in the topsoil layer (0-20 cm),far more than those in the lower soil layers.The RENI of pbytocommunities is higher than that of pure stands or monocultures.The distribution of RENI by root diameter can be divided into four types:J-type,inverse J-type,recumbent S-type,and U-type.RENI is positively correlated with the wet biomass of aboveground level stems,branches,and plant leaves,and with the species richness of phytocommunities.Although the RENIs of plantations in rehabilitated fields are a little lower than those of natural forests,they are higher than those of cultivated crops.The RENIs of three community types (Picea crassifolia+Hippophae rhamnoides ssp.sinensis,H.rhamnoides ssp.sinensis,and P.crassifolia) in rehabilitated fields benefit greatly from the restoration project.The implementation of the CCFG project is important for the increase in RENI and the multiple functions of

  8. Water Deficit Enhances C Export to the Roots in Arabidopsis thaliana Plants with Contribution of Sucrose Transporters in Both Shoot and Roots.

    Science.gov (United States)

    Durand, Mickaël; Porcheron, Benoît; Hennion, Nils; Maurousset, Laurence; Lemoine, Rémi; Pourtau, Nathalie

    2016-03-01

    Root high plasticity is an adaptation to its changing environment. Water deficit impairs growth, leading to sugar accumulation in leaves, part of which could be available to roots via sucrose (Suc) phloem transport. Phloem loading is widely described in Arabidopsis (Arabidopsis thaliana), while unloading in roots is less understood. To gain information on leaf-to-root transport, a soil-based culture system was developed to monitor root system architecture in two dimensions. Under water deficit (50% of soil water-holding capacity), total root length was strongly reduced but the depth of root foraging and the shape of the root system were less affected, likely to improve water uptake. (14)CO2 pulse-chase experiments confirmed that water deficit enhanced carbon (C) export to the roots, as suggested by the increased root-to-shoot ratio. The transcript levels of AtSWEET11 (for sugar will eventually be exported transporter), AtSWEET12, and AtSUC2 (for Suc carrier) genes, all three involved in Suc phloem loading, were significantly up-regulated in leaves of water deficit plants, in accordance with the increase in C export from the leaves to the roots. Interestingly, the transcript levels of AtSUC2 and AtSWEET11 to AtSWEET15 were also significantly higher in stressed roots, underlying the importance of Suc apoplastic unloading in Arabidopsis roots and a putative role for these Suc transporters in Suc unloading. These data demonstrate that, during water deficit, plants respond to growth limitation by allocating relatively more C to the roots to maintain an efficient root system and that a subset of Suc transporters is potentially involved in the flux of C to and in the roots. PMID:26802041

  9. Braiding operator via quantum cluster algebra

    International Nuclear Information System (INIS)

    We construct a braiding operator in terms of the quantum dilogarithm function based on the quantum cluster algebra. We show that it is a q-deformation of the R-operator for which hyperbolic octahedron is assigned. Also shown is that, by taking q to be a root of unity, our braiding operator reduces to the Kashaev RK-matrix up to a simple gauge-transformation. This article is part of a special issue of Journal of Physics A: Mathematical and Theoretical devoted to ‘Cluster algebras in mathematical physics’. (paper)

  10. Philosophical Roots of Cosmology

    Science.gov (United States)

    Ivanovic, M.

    2008-10-01

    We shall consider the philosophical roots of cosmology in the earlier Greek philosophy. Our goal is to answer the question: Are earlier Greek theories of pure philosophical-mythological character, as often philosophers cited it, or they have scientific character. On the bases of methodological criteria, we shall contend that the latter is the case. In order to answer the question about contemporary situation of the relation philosophy-cosmology, we shall consider the next question: Is contemporary cosmology completely independent of philosophical conjectures? The answer demands consideration of methodological character about scientific status of contemporary cosmology. We also consider some aspects of the relation contemporary philosophy-cosmology.

  11. Cold Temperature Delays Wound Healing in Postharvest Sugarbeet Roots.

    Science.gov (United States)

    Fugate, Karen K; Ribeiro, Wellington S; Lulai, Edward C; Deckard, Edward L; Finger, Fernando L

    2016-01-01

    Storage temperature affects the rate and extent of wound-healing in a number of root and tuber crops. The effect of storage temperature on wound-healing in sugarbeet (Beta vulgaris L.) roots, however, is largely unknown. Wound-healing of sugarbeet roots was investigated using surface-abraded roots stored at 6 and 12°C for 28 days. Surface abrasions are common injuries of stored roots, and the storage temperatures used are typical of freshly harvested or rapidly cooled roots. Transpiration rate from the wounded surface and root weight loss were used to quantify wound healing. At 12°C, transpiration rate from the wounded surface declined within 14 days and wounded roots lost weight at a rate similar to unwounded controls. At 6°C, transpiration rate from the wounded surface did not decline in the 28 days after injury, and wounded roots lost 44% more weight than controls after 28 days storage. Melanin formation, lignification, and suberization occurred more rapidly at 12°C than at 6°C, and a continuous layer of lignified and suberized cells developed at 12°C, but not at 6°C. Examination of enzyme activities involved in melanin, lignin, and suberin formation indicated that differences in melanin formation at 6 and 12°C were related to differences in polyphenol oxidase activity, although no relationships between suberin or lignin formation and phenylalanine ammonia lyase or peroxidase activity were evident. Wound-induced respiration was initially greater at 12°C than at 6°C. However, with continued storage, respiration rate of wounded roots declined more rapidly at 12°C, and over 28 days, the increase in respiration due to injury was 52% greater in roots stored at 6°C than in roots stored at 12°C. The data indicate that storage at 6°C severely slowed and impaired wound-healing of surface-abraded sugarbeet roots relative to roots stored at 12°C and suggest that postharvest losses may be accelerated if freshly harvested roots are cooled too quickly. PMID

  12. An analysis of hospital brand mark clusters.

    Science.gov (United States)

    Vollmers, Stacy M; Miller, Darryl W; Kilic, Ozcan

    2010-07-01

    This study analyzed brand mark clusters (i.e., various types of brand marks displayed in combination) used by hospitals in the United States. The brand marks were assessed against several normative criteria for creating brand marks that are memorable and that elicit positive affect. Overall, results show a reasonably high level of adherence to many of these normative criteria. Many of the clusters exhibited pictorial elements that reflected benefits and that were conceptually consistent with the verbal content of the cluster. Also, many clusters featured icons that were balanced and moderately complex. However, only a few contained interactive imagery or taglines communicating benefits. PMID:20582849

  13. Auxins differentially regulate root system architecture and cell cycle protein levels in maize seedlings.

    Science.gov (United States)

    Martínez-de la Cruz, Enrique; García-Ramírez, Elpidio; Vázquez-Ramos, Jorge M; Reyes de la Cruz, Homero; López-Bucio, José

    2015-03-15

    Maize (Zea mays) root system architecture has a complex organization, with adventitious and lateral roots determining its overall absorptive capacity. To generate basic information about the earlier stages of root development, we compared the post-embryonic growth of maize seedlings germinated in water-embedded cotton beds with that of plants obtained from embryonic axes cultivated in liquid medium. In addition, the effect of four different auxins, namely indole-3-acetic acid (IAA), 1-naphthaleneacetic acid (NAA), indole-3-butyric acid (IBA) and 2,4-dichlorophenoxyacetic acid (2,4-D) on root architecture and levels of the heat shock protein HSP101 and the cell cycle proteins CKS1, CYCA1 and CDKA1 were analyzed. Our data show that during the first days after germination, maize seedlings develop several root types with a simultaneous and/or continuous growth. The post-embryonic root development started with the formation of the primary root (PR) and seminal scutellar roots (SSR) and then continued with the formation of adventitious crown roots (CR), brace roots (BR) and lateral roots (LR). Auxins affected root architecture in a dose-response fashion; whereas NAA and IBA mostly stimulated crown root formation, 2,4-D showed a strong repressing effect on growth. The levels of HSP101, CKS1, CYCA1 and CDKA in root and leaf tissues were differentially affected by auxins and interestingly, HSP101 registered an auxin-inducible and root specific expression pattern. Taken together, our results show the timing of early branching patterns of maize and indicate that auxins regulate root development likely through modulation of the HSP101 and cell cycle proteins. PMID:25615607

  14. ANALGESIC ACTIVITY OF ROOT EXTRACT OF SOLANUM MELONGENA LINN ROOT

    OpenAIRE

    Srivastava Ashish; Sanjay Yadav

    2011-01-01

    The present study was aimed at Pharmacognostic study and biological evaluation of analgesic activity of plants roots. The roots of plants were studies for Pharmacognostic characteristics namely, morphology, microscopy, physicochemical parameters, which can be of utilized in identification/authentication of the plant and/or its roots in crude drug form. The preliminary phytochemical screening of the dry residue was carried out by the chemical test and thin layer chromatographic method. The p...

  15. Dipole oscillation modes in light α -clustering nuclei

    Science.gov (United States)

    He, W. B.; Ma, Y. G.; Cao, X. G.; Cai, X. Z.; Zhang, G. Q.

    2016-07-01

    The α cluster states are discussed in a model frame of extended quantum molecular dynamics. Different α cluster structures are studied in detail, such as 8Be two-α cluster structure, 12C triangle structure, 12 chain structure, 16O chain structure, 16O kite structure, and 16O square structure. The properties studied include the width of wave packets for different α clusters, momentum distribution, and the binding energy among α clusters. We also discuss how the α cluster degree of freedom affects nuclear collective vibrations. The cluster configurations in 12C and 16O are found to have corresponding characteristic spectra of giant dipole resonance (GDR), and the coherences of different α clusters' dipole oscillations are described in detail. The geometrical and dynamical symmetries of α -clustering configurations are responsible for the number and centroid energies of peaks of GDR spectra. Therefore, the GDR can be regarded as an effective probe to diagnose different α cluster configurations in light nuclei.

  16. How can we harness quantitative genetic variation in crop root systems for agricultural improvement?

    Science.gov (United States)

    Topp, Christopher N; Bray, Adam L; Ellis, Nathanael A; Liu, Zhengbin

    2016-03-01

    Root systems are a black box obscuring a comprehensive understanding of plant function, from the ecosystem scale down to the individual. In particular, a lack of knowledge about the genetic mechanisms and environmental effects that condition root system growth hinders our ability to develop the next generation of crop plants for improved agricultural productivity and sustainability. We discuss how the methods and metrics we use to quantify root systems can affect our ability to understand them, how we can bridge knowledge gaps and accelerate the derivation of structure-function relationships for roots, and why a detailed mechanistic understanding of root growth and function will be important for future agricultural gains. PMID:26911925

  17. Studies on the development of mycorrhizal fine roots of Norway spruce in declining forests

    Energy Technology Data Exchange (ETDEWEB)

    Blaschke, H.

    1986-12-01

    On a comparative basis, results from inventories in declining Norway spruce stands and from field experiments were obtained concerning the formation and the impairment of fine roots and mycorrhizae. Decreased ability of affected trees to reproduce mycorrhizal roots was more pronounced in the mineral soil horizons. Besides the deterioration of fine root system, the stages of development and the process of differentiation of short roots and associated ectomycorrhizae are described. The results indicate, that both the structure of the fungal component and the status of the apical meristem are crucial for the characterization of below-ground symptoms and further for the functioning of mycorrhizal short roots.

  18. Shoot and root dry weight in drought exposed tomato populations

    OpenAIRE

    Brdar-Jokanović Milka; Girek Zdenka; Pavlović Suzana; Ugrinović Milan; Zdravković Jasmina

    2014-01-01

    This research was conducted with the aim to among forty-one tested tomato (Lycopersicon esculentum Mill) populations distinguish those tolerant to limited water supply. Tolerance assessments were performed by using sixteen drought stress selection indices calculated on the basis of tomato shoot and root dry weight yields determined at water stress and non-stress conditions. Populations were differentiated in groups using the method of cluster analysis. The ...

  19. Perennial roots to immortality.

    Science.gov (United States)

    Munné-Bosch, Sergi

    2014-10-01

    Maximum lifespan greatly varies among species, and it is not strictly determined; it can change with species evolution. Clonal growth is a major factor governing maximum lifespan. In the plant kingdom, the maximum lifespans described for clonal and nonclonal plants vary by an order of magnitude, with 43,600 and 5,062 years for Lomatia tasmanica and Pinus longaeva, respectively. Nonclonal perennial plants (those plants exclusively using sexual reproduction) also present a huge diversity in maximum lifespans (from a few to thousands of years) and even more interestingly, contrasting differences in aging patterns. Some plants show a clear physiological deterioration with aging, whereas others do not. Indeed, some plants can even improve their physiological performance as they age (a phenomenon called negative senescence). This diversity in aging patterns responds to species-specific life history traits and mechanisms evolved by each species to adapt to its habitat. Particularities of roots in perennial plants, such as meristem indeterminacy, modular growth, stress resistance, and patterns of senescence, are crucial in establishing perenniality and understanding adaptation of perennial plants to their habitats. Here, the key role of roots for perennial plant longevity will be discussed, taking into account current knowledge and highlighting additional aspects that still require investigation. PMID:24563283

  20. An Efficient Density based Improved K- Medoids Clustering algorithm

    Directory of Open Access Journals (Sweden)

    Masthan Mohammed

    2012-12-01

    Full Text Available Mining knowledge from large amounts of spatial data is known as spatial data mining. It becomes a highly demanding field because huge amounts of spatial data have been collected in various applications ranging from geo-spatial data to bio-medical knowledge. The database can be clustered in many ways depending on the clustering algorithm employed, parameter settings used, and other factors. Multiple clustering can be combined so that the final partitioning of data provides better clustering. In this paper, an efficient density based k-medoids clustering algorithm has been proposed to overcome the drawbacks of DBSCAN and kmedoids clustering algorithms. Clustering is the process of classifying objects into different  groups  by  partitioning  sets  of  data  into  a  series  of subsets called clusters. Clustering has taken its roots from algorithms like k-medoids and k-medoids. However conventional k-medoids clustering algorithm suffers from many limitations. Firstly, it needs to have prior knowledge about the number of cluster parameter k. Secondly, it also initially needs to make random selection of k representative objects and if these initial k medoids are not selected properly then natural cluster may not be obtained. Thirdly, it is also sensitive to the order of input dataset.

  1. NEO-FFI personality clusters in trichotillomania.

    Science.gov (United States)

    Keuthen, Nancy J; Tung, Esther S; Tung, Matthew G; Curley, Erin E; Flessner, Christopher A

    2016-05-30

    The purpose of this study was to determine whether personality prototypes exist among hair pullers and if these groups differ in hair pulling (HP) characteristics, clinical correlates, and quality of life. 164 adult hair pullers completed the NEO-Five Factor Inventory (NEO-FFI; Costa and McCrae, 1992) and self-report measures of HP severity, HP style, affective state, and quality of life. A latent class cluster analysis using NEO-FFI scores was performed to separate participants into clusters. Bonferroni-corrected t-tests were used to compare clusters on HP, affective, and quality of life variables. Multiple regression was used to determine which variables significantly predicted quality of life. Two distinct personality prototypes were identified. Cluster 1 (n=96) had higher neuroticism and lower extraversion, agreeableness, and conscientiousness when compared to cluster 2 (n=68). No significant differences in demographics were reported for the two personality clusters. The clusters differed on extent of focused HP, severity of depression, anxiety, and stress, as well as quality of life. Those in cluster 1 endorsed greater depression, anxiety, and stress, and worse quality of life. Additionally, only depression and cluster membership (based on NEO scores) significantly predicted quality of life. PMID:27016621

  2. Partitional clustering algorithms

    CERN Document Server

    2015-01-01

    This book summarizes the state-of-the-art in partitional clustering. Clustering, the unsupervised classification of patterns into groups, is one of the most important tasks in exploratory data analysis. Primary goals of clustering include gaining insight into, classifying, and compressing data. Clustering has a long and rich history that spans a variety of scientific disciplines including anthropology, biology, medicine, psychology, statistics, mathematics, engineering, and computer science. As a result, numerous clustering algorithms have been proposed since the early 1950s. Among these algorithms, partitional (nonhierarchical) ones have found many applications, especially in engineering and computer science. This book provides coverage of consensus clustering, constrained clustering, large scale and/or high dimensional clustering, cluster validity, cluster visualization, and applications of clustering. Examines clustering as it applies to large and/or high-dimensional data sets commonly encountered in reali...

  3. Removal of root filling materials.

    LENUS (Irish Health Repository)

    Duncan, H.F. Chong, B.S.

    2011-05-01

    Safe, successful and effective removal of root filling materials is an integral component of non-surgical root canal re-treatment. Access to the root canal system must be achieved in order to negotiate to the canal terminus so that deficiencies in the original treatment can be rectified. Since a range of materials have been advocated for filling root canals, different techniques are required for their removal. The management of commonly encountered root filling materials during non-surgical re-treatment, including the clinical procedures necessary for removal and the associated risks, are reviewed. As gutta-percha is the most widely used and accepted root filling material, there is a greater emphasis on its removal in this review.

  4. ROOT Tutorial for Summer Students

    CERN Document Server

    CERN. Geneva; Piparo, Danilo

    2015-01-01

    ROOT is a "batteries-included" tool kit for data analysis, storage and visualization. It is widely used in High Energy Physics and other disciplines such as Biology, Finance and Astrophysics. This event is an introductory tutorial to ROOT and comprises a front lecture and hands on exercises. IMPORTANT NOTE: The tutorial is based on ROOT 6.04 and NOT on the ROOT5 series.  IMPORTANT NOTE: if you have ROOT 6.04 installed on your laptop, you will not need to install any virtual machine. The instructions showing how to install the virtual machine on which you can find ROOT 6.04 can be found under "Material" on this page.

  5. Knowledge between communities of practice and firms in clusters

    DEFF Research Database (Denmark)

    Reinau, Kristian Hegner

    Currently there is growing focus on how cluster internal and cluster external relations affect the creation of knowledge in companies placed in clusters. However, the current theories on this topic are too simple and the interplay between internal and external relations is relatively unknown. Thi...

  6. Cluster Evaluation of Density Based Subspace Clustering

    OpenAIRE

    Sembiring, Rahmat Widia; Zain, Jasni Mohamad

    2010-01-01

    Clustering real world data often faced with curse of dimensionality, where real world data often consist of many dimensions. Multidimensional data clustering evaluation can be done through a density-based approach. Density approaches based on the paradigm introduced by DBSCAN clustering. In this approach, density of each object neighbours with MinPoints will be calculated. Cluster change will occur in accordance with changes in density of each object neighbours. The neighbours of each object ...

  7. Clustering with Spectral Methods

    OpenAIRE

    Gaertler, Marco

    2002-01-01

    Grouping and sorting are problems with a great tradition in the history of mankind. Clustering and cluster analysis is a small aspect in the wide spectrum. But these topics have applications in most scientific disciplines. Graph clustering is again a little fragment in the clustering area. Nevertheless it has the potential for new pioneering and innovative methods. One such method is the Markov Clustering presented by van Dongen in 'Graph Clustering by Flow Simulation'. We investigated the qu...

  8. Sparse Convex Clustering

    OpenAIRE

    Wang, Binhuan; Zhang, Yilong; Sun, Wei; Fang, Yixin

    2016-01-01

    Convex clustering, a convex relaxation of k-means clustering and hierarchical clustering, has drawn recent attentions since it nicely addresses the instability issue of traditional nonconvex clustering methods. Although its computational and statistical properties have been recently studied, the performance of convex clustering has not yet been investigated in the high-dimensional clustering scenario, where the data contains a large number of features and many of them carry no information abo...

  9. Facilitative root interactions in intercrops

    DEFF Research Database (Denmark)

    Hauggaard-Nielsen, H.; Jensen, E.S.

    2005-01-01

    Facilitation takes place when plants ameliorate the environment of their neighbours, and increase their growth and survival. Facilitation occurs in natural ecosystems as well as in agroecosystems. We discuss examples of facilitative root interactions in intercropped agroecosystems; including...... root architecture, exudation of growth stimulating substances, and biofumigation. Facilitative root interactions are most likely to be of importance in nutrient poor soils and in low-input agroecosystems due to critical interspecific competition for plant growth factors. However, studies from more...

  10. Globular clusters in the Galactic bulge

    CERN Document Server

    Bica, E; Barbuy, B

    2015-01-01

    A view of the Galactic bulge by means of their globular clusters is necessary for a deep understanding of its formation and evolution. Connections between the globular cluster and field star properties in terms of kinematics, orbits, chemical abundances and ages should shed light on different stellar population components. Based on spatial distribution and metallicity, we define a probable best list of bulge clusters, containing 43 entries. Future work on newly discovered objects, mostly from the VVV survey, is suggested. These candidates might alleviate the issue of missing clusters on the far side of the bulge. We discuss the reddening law affecting the cluster distances towards the center of the Galaxy, and conclude that the most suitable total-to-selective absorption value appears to be R$_{\\rm V}$=3.2, in agreement with recent analyses. An update of elemental abundances for bulge clusters is provided.

  11. Globular Clusters in the Galactic Bulge

    Science.gov (United States)

    Bica, E.; Ortolani, S.; Barbuy, B.

    2016-06-01

    A view of the Galactic bulge by means of their globular clusters is fundamental for a deep understanding of its formation and evolution. Connections between the globular cluster and field star properties in terms of kinematics, orbits, chemical abundances, and ages should shed light on different stellar population components. Based on spatial distribution and metallicity, we define a probable best list of bulge clusters, containing 43 entries. Future work on newly discovered objects, mostly from the VVV survey, is suggested. These candidates might alleviate the issue of missing clusters on the far side of the bulge. We discuss the reddening law affecting the cluster distances towards the centre of the Galaxy, and conclude that the most suitable total-to-selective absorption value appears to be R V=3.2, in agreement with recent analyses. An update of elemental abundances for bulge clusters is provided.

  12. Role of adventitious roots in water relations of tamarack (Larix laricina seedlings exposed to flooding

    Directory of Open Access Journals (Sweden)

    Calvo-Polanco Mónica

    2012-06-01

    Full Text Available Abstract Background Flooding reduces supply of oxygen to the roots affecting plant water uptake. Some flooding-tolerant tree species including tamarack (Larix laricina (Du Roi K. Koch produce adventitious roots in response to flooding. These roots were reported to have higher hydraulic conductivity under flooding conditions compared with non-adventitious roots. In the present study, we examined structural and functional modifications in adventitious roots of tamarack seedlings to explain their flooding tolerance. Results Seedlings were subjected to the flooding treatment for six months, which resulted in an almost complete disintegration of the existing root system and its replacement with adventitious roots. We compared gas exchange parameters and water relations of flooded plants with the plants growing in well-drained soil and examined the root structures and root water transport properties. Although flooded seedlings had lower needle chlorophyll concentrations, their stomatal conductance, net photosynthesis rates and shoot water potentials were similar to non-flooded plants, indicative of flooding tolerance. Flooded adventitious roots had higher activation energy and a higher ratio of apoplastic to cell-to-cell water flow compared with non-flooded control roots as determined with the 1-hydroxypirene 3,6,8-trisulfonic acid apoplastic tracer dye. The adventitious roots in flooded plants also exhibited retarded xylem and endodermal development and accumulated numerous starch grains in the cortex. Microscopic examination of root sections treated with the PIP1 and PIP2 antibodies revealed high immunoreactivity in the cortex of non-flooded roots, as compared with flooded roots. Conclusions Structural modifications of adventitious roots suggest increased contribution of apoplastic bypass to water flow. The reduced dependence of roots on the hypoxia-sensitive aquaporin-mediated water transport is likely among the main mechanisms allowing tamarack

  13. 集群内中小企业信贷融资因素分析——基于常州三个产业集群的实证%Analysis on Factors Affecting Credit Financing by SMEs within Industrial Clusters——Based on Three Industrial Clusters in Changzhou

    Institute of Scientific and Technical Information of China (English)

    马鸿杰; 胡汉辉

    2009-01-01

    The paper firstly makes an empirical analysis on factors affecting credit financing by small and medium enterprises (SME) within an industrial duster. The analysis is based on data collected from three industrial clus-ters in Changzhou, i.e. the textile industry in Hutang, floor production in Henglin and lamp manufacturing in Zouqu. It is found that profitability, mortgage abundance and cluster degree are important factor affecting financing capability of SMEs. Secondly, through making eointegration test between the duster degree and the financing ca-pability of SMEs, the paper focuses on analyzing financing advantages of SMEs from the perspectives of reputation importance, information sharing enterprise cooperation and credit risks. Finally, it concludes that financing prob-lems facing SMEs may be solved by developing industrial clusters of SMEs.%以常州湖塘纺织、横林地板、邹区灯具三大集群为例,首先分析了群内中小企业的信贷融资因素,得出企业的盈利能力、有无充足抵押物、企业所在地产业集群化程度是影响中小企业信贷融资能力的重要因素;其次通过对集群化程度与企业信贷融资能力协整检验后,重点从集群的信誉重要性、信息共享、企业合作、信贷风险等方面分析群内中小企业的融资优势;最后分析得出可以通过中小企业的集群化发展破解中小企业融资难的困境.

  14. On roots of Dehn twists

    CERN Document Server

    Monden, Naoyuki

    2009-01-01

    Margalit and Schleimer constructed nontrivial roots of the Dehn twist about a nonseparating curve. We prove that the conjugacy classes of roots of the Dehn twist about a nonseparating curve correspond to the conjugacy classes of periodic maps with certain conditions. Futhermore, we give data set which determine the conjugacy class of a root. As a consequence, we can find the minimum degree and the maximum degree, and show that the degree must be odd. Also, we give Dehn twist expression of the root of degree 3.

  15. Root system in declining forests

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, F.H.

    1987-07-11

    Trees with obligate ectomycorrhiza are more sensitive to environmental stress than those without ectomycorrhiza or with facultative ectomycorrhiza. With spruce seedlings growing in humus material from a declining spruce forest an experimental proof was given, that reduction of the mineral nitrogen content by adding sawdust to the rooting substrate increases the share of root tips converted to ectomycorrhizas. A close correlation has been found between the mycorrhiza frequency and the number of root tips. This means, that the ramification of a root system is the more intense the better the conditions for mycorrhizal development are.

  16. Feynman Diagrams and Rooted Maps

    CERN Document Server

    Prunotto, A; Czerski, P

    2013-01-01

    The {\\em Rooted Maps Theory}, a branch of the Theory of Homology, is shown to be a powerful tool for investigating the topological properties of Feynman diagrams, related to the single particle propagator in the quantum many-body systems. The numerical correspondence between the number of this class of Feynman diagrams as a function of perturbative order and the number of rooted maps as a function of the number of edges is studied. A graphical procedure to associate Feynman diagrams and rooted maps is then stated. Finally, starting from rooted maps principles, an original definition of the {\\em genus of a Feynman diagram}, which totally differs from the usual one, is given.

  17. Effects of root herbivory on pyrrolizidine alkaloid content and aboveground plant-herbivore-parasitoid interactions in Jacobaea vulgaris

    NARCIS (Netherlands)

    Kostenko, O.; Mulder, P.P.J.; Bezemer, T.M.

    2013-01-01

    The importance of root herbivory is increasingly recognized in ecological studies, and the effects of root herbivory on plant growth, chemistry, and performance of aboveground herbivores have been relatively well studied. However, how belowground herbivory by root feeding insects affects aboveground

  18. Effects of Root Herbivory on Pyrrolizidine Alkaloid Content and Aboveground Plant-Herbivore-Parasitoid Interactions in Jacobaea Vulgaris

    NARCIS (Netherlands)

    Kostenko, O.; Mulder, P.P.J.; Bezemer, T.M.

    2013-01-01

    The importance of root herbivory is increasingly recognized in ecological studies, and the effects of root herbivory on plant growth, chemistry, and performance of aboveground herbivores have been relatively well studied. However, how belowground herbivory by root feeding insects affects aboveground

  19. Differential responses of grapevine rootstocks to water stress are associated with adjustments in fine root hydraulic physiology and suberization

    Science.gov (United States)

    Water deficits are known to alter fine root structure and function, but little is known about how these responses contribute to differences in drought resistance across grapevine rootstocks. We studied how water deficit affects root anatomical and physiological characteristics in two grapevine root...

  20. Root cause analysis

    International Nuclear Information System (INIS)

    This article provides some fundamental techniques of evaluating human performance and equipment related events which are in use in Krsko NPP. Before the large industrial accidents the human factor was considered as very reliable and was not accepted as a possible source of errors. Today it is evident that safety is a proper combination of factors associated with people, technology and organization. Determining the cause of equipment failures is a much more enjoyable, exercise than doing the same for human errors. People are emotional: they can be angry, scared, defensive, not trustful. Because of all that the determination of causes for human errors is much more difficult.In many cases the definition of human factors relates to operators as the source of the human errors. Such an approach restricts the search for the true root cause of an event. In reality the human factor is associated with operators as well as with managers, designers, instructors, maintenance people etc. Operating experience and in-depth analysis with the resulting lessons learnt are all evidence of the relevance of human errors for safety. The nuclear power plant industry has estimated the risk due to human errors closing to 70%. It is therefore obvious that sophisticated techniques are needed to focus on human errors. The root cause analysis in NPP Krsko is based on the following methods: Event and Causal Factor Charting, Change Analysis, Barrier Analysis, MORT (Management Oversight and Risk Tree Analysis) and Human Performance Evaluation. Event and casual Factor Charting is used for investigation of complex problems which need to be visualized in the form of a chart so as to provide a better understanding of the chronology of an event. Change Analysis is usually used for a particular problem with the equipment failure by using key questions: what?, when?, where?, who? and how? to find a final answer to the question WHY something happened. Barrier Analysis is used for procedural and

  1. Maximal rank root subsystems of hyperbolic root systems

    OpenAIRE

    Tumarkin, P.

    2003-01-01

    A Kac-Moody algebra is called hyperbolic if it corresponds to a generalized Cartan matrix of hyperbolic type. We study root subsystems of root systems of hyperbolic algebras. In this paper, we classify maximal rank regular hyperbolic subalgebras of hyperbolic Kac-Moody algebras.

  2. Radiographing roots and shoots

    International Nuclear Information System (INIS)

    The effect of seed orientation on germination time and on shoot and root growth patterns is studied. Neutron radiography is used to observe the development of 4 types of plants, maize, greenpea, soya bean and padi. These plants were grown in varying orientations; sand sizes, sand thicknesses, and level of water content. Radiography of the seeds and plants were obtained for time exposure ranging from 3-12 hours and at reactor thermal power level, ranging from 500-750 kilowatts. Results obtained showed that seeds planted in varying orientations need different length of time for shoot emergence. Neutron radiography is now developed to other areas of non-industrial applications in Malaysia. (A.J.)

  3. Cluster categories and cluster-tilted algebras

    OpenAIRE

    Torkildsen, Hermund Andre

    2006-01-01

    We have given an introduction to the theory of cluster categories and cluster-tilted algebras, and this was one of our main objectives in this thesis. We have seen that cluster-tilted algebras are relation-extension algebras, and this gave us a way of constructing the quiver of a cluster-tilted algebra from a tilted algebra. A cluster-tilted algebra of finite representation type is determined by its quiver, and this raised questions about the generality of this result. We defined a new class...

  4. Root Anatomy and Root Canal Configuration of Human Permanent Mandibular Premolars: A Systematic Review

    Directory of Open Access Journals (Sweden)

    Jojo Kottoor

    2013-01-01

    Full Text Available Introduction. Mandibular premolars have been reported with complex anatomical aberrations, making them one of the most difficult teeth to manage endodontically. Methodology. An exhaustive search was undertaken to identify associated anatomic studies of mandibular premolars through MEDLINE/PubMed database using keywords, and a systematic review of the relevant articles was performed. Chi-square test with Yates correction was performed to assess the statistical significance of any anatomic variations between ethnicities and within populations of the same ethnicity. Documented case reports of variations in mandibular premolar anatomy were also identified and reviewed. Results. Thirty-six anatomic studies were analyzed which included 12,752 first premolars and nineteen studies assessing 6646 second premolars. A significant variation in the number of roots, root canals, and apical foramen was observed between Caucasian, Indian, Mongoloid, and Middle Eastern ethnicities.The most common anatomic variation was C-shaped canals in mandibular first premolars with highest incidence in Mongoloid populations (upto 24% while dens invaginatus was the most common developmental anomaly. Conclusions. A systematic review of mandibular premolars based on ethnicity and geographic clusters offered enhanced analysis of the prevalence of number of roots and canals, their canal configuration, and other related anatomy.

  5. Turbulence for different background conditions using fuzzy logic and clustering

    OpenAIRE

    K. Satheesan; Kirkwood, S

    2010-01-01

    Wind and turbulence estimated from MST radar observations in Kiruna, in Arctic Sweden are used to characterize turbulence in the free troposphere using data clustering and fuzzy logic. The root mean square velocity, νfca, a diagnostic of turbulence is clustered in terms of hourly wind speed, direction, vertical wind speed, and altitude of the radar observations, which are the predictors. The predictors are graded over an interval of zero to one through an input membership...

  6. Turbulence for different background conditions using fuzzy logic and clustering

    OpenAIRE

    K. Satheesan; Kirkwood, S

    2010-01-01

    Wind and turbulence estimated from MST radar observations in Kiruna, in Arctic Sweden are used to characterize turbulence in the free troposphere using data clustering and fuzzy logic. The root mean square velocity, νfca, a diagnostic of turbulence is clustered in terms of hourly wind speed, direction, vertical wind speed, and altitude of the radar observations, which are the predictors. The predictors are graded over an interval of zero to one through an input m...

  7. Compensatory Root Water Uptake of Overlapping Root Systems

    Science.gov (United States)

    Agee, E.; Ivanov, V. Y.; He, L.; Bisht, G.; Shahbaz, P.; Fatichi, S.; Gough, C. M.; Couvreur, V.; Matheny, A. M.; Bohrer, G.

    2015-12-01

    Land-surface models use simplified representations of root water uptake based on biomass distributions and empirical functions that constrain water uptake during unfavorable soil moisture conditions. These models fail to capture the observed hydraulic plasticity that allows plants to regulate root hydraulic conductivity and zones of active uptake based on local gradients. Recent developments in root water uptake modeling have sought to increase its mechanistic representation by bridging the gap between physically based microscopic models and computationally feasible macroscopic approaches. It remains to be demonstrated whether bulk parameterization of microscale characteristics (e.g., root system morphology and root conductivity) can improve process representation at the ecosystem scale. We employ the Couvreur method of microscopic uptake to yield macroscopic representation in a coupled soil-root model. Using a modified version of the PFLOTRAN model, which represents the 3-D physics of variably saturated soil, we model a one-hectare temperate forest stand under natural and synthetic climatic forcing. Our results show that as shallow soil layers dry, uptake at the tree and stand level shift to deeper soil layers, allowing the transpiration stream demanded by the atmosphere. We assess the potential capacity of the model to capture compensatory root water uptake. Further, the hydraulic plasticity of the root system is demonstrated by the quick response of uptake to rainfall pulses. These initial results indicate a promising direction for land surface models in which significant three-dimensional information from large root systems can be feasibly integrated into the forest scale simulations of root water uptake.

  8. Cluster usage increasing by virtualization for on-line clusters

    International Nuclear Information System (INIS)

    The ALICE HLT Cluster is a computing farm doing on-line event processing for the ALICE Experiment at CERN. It is known that at run-time of the experiment there are phases where few or no data is available for processing. The same applies for maintenance cycles of both the experiment and the cluster. With respect to the costs of maintaining and running such a cluster there is the need to maximize the usage of this computing facility. A toolset has been developed which makes free cluster resources available for third-party applications. The toolset uses virtualization to host third party applications and, most importantly, can be configured such, that the event processing is not affected by third party applications. This is achieved by both local and central resource (re)allocation mechanisms, e.g. by using suspend/resume or live-migration. In this work results like increased cluster usage are shown for the co-operation of event-processing and third party applications. Furthermore a synthesized, more general application is run together with third party applications to demonstrate the suitability of the toolset for other environments.

  9. Fluid dynamics of aortic root dilation in Marfan syndrome

    CERN Document Server

    Querzoli, Giorgio; Espa, Stefania; Costantini, Martina; Sorgini, Francesca

    2014-01-01

    Aortic root dilation and propensity to dissection are typical manifestations of the Marfan Syndrome (MS), a genetic defect leading to the degeneration of the elastic fibres. Dilation affects the structure of the flow and, in turn, altered flow may play a role in vessel dilation, generation of aneurysms, and dissection. The aim of the present work is the investigation in-vitro of the fluid dynamic modifications occurring as a consequence of the morphological changes typically induced in the aortic root by MS. A mock-loop reproducing the left ventricle outflow tract and the aortic root was used to measure time resolved velocity maps on a longitudinal symmetry plane of the aortic root. Two dilated model aortas, designed to resemble morphological characteristics typically observed in MS patients, have been compared to a reference, healthy geometry. The aortic model was designed to quantitatively reproduce the change of aortic distensibility caused by MS. Results demonstrate that vorticity released from the valve ...

  10. Research progress of antagonistic interactions among root canal irrigations disease

    Directory of Open Access Journals (Sweden)

    Chen QU

    2013-07-01

    Full Text Available Root canal therapy is the most effective way to treat various pulposis and periapical disease. Simple mechanical apparatus can not clean root canal thoroughly, but may affect tight filling instead. It can achieve a satisfactory cleansing effect only when it is combined with a chemical solution. Irrigation fluid for root canal should possess the properties of tissue dissolution, antimicrobial, lubrication, and removal of smear layer. So far, no solution is able to fulfill all these functions. Therefore, a combined use of multiple irrigation solutions is suggested. It can not only achieve good effect in cleaning and disinfection, also it can lower the concentration of different solutions, thus reducing the side effects. Nevertheless, some experiments proved that antagonism existed among the chemicals used for irrigations. The purpose of present article is to review the antagonistic effect among the chemicals used for irrigation when they are used together for root canal treatment.

  11. Evaluation of Strategies to Separate Root-Associated Microbial Communities: A Crucial Choice in Rhizobiome Research

    Science.gov (United States)

    Richter-Heitmann, Tim; Eickhorst, Thilo; Knauth, Stefan; Friedrich, Michael W.; Schmidt, Hannes

    2016-01-01

    Plants shape distinct, species-specific microbiomes in their rhizospheres. A main premise for evaluating microbial communities associated with root-soil compartments is their successful separation into the rhizosphere (soil-root interface), the rhizoplane (root surface), and the endosphere (inside roots). We evaluated different approaches (washing, sonication, and bleaching) regarding their efficiency to separate microbial cells associated with different root compartments of soil-grown rice using fluorescence microscopy and community fingerprinting of 16S rRNA genes. Vigorous washing detached 45% of the rhizoplane population compared to untreated roots. Additional sonication reduced rhizoplane-attached microorganisms by up to 78% but caused various degrees of root tissue destruction at all sonication intensities tested. Treatment with sodium hypochlorite almost completely (98%) removed rhizoplane-associated microbial cells. Community fingerprinting revealed that microbial communities obtained from untreated, washed, and sonicated roots were not statistically distinguishable. Hypochlorite-treated roots harbored communities significantly different from all other samples, likely representing true endospheric populations. Applying these procedures to other root samples (bean and clover) revealed that treatment efficiencies were strongly affected by root morphological parameters such as root hair density and rigidity of epidermis. Our findings suggest that a careful evaluation of separation strategies prior to molecular community analysis is indispensable, especially when endophytes are the subject of interest. PMID:27252690

  12. Root Morphology and Zn2+ Uptake Kinetics of the Zn Hyperaccumulator of Sedum alfredii Hance

    Institute of Scientific and Technical Information of China (English)

    Ting-Qiang LI; Xiao-E YANG; Zhen-Li HE; Jin-Yan YANG

    2005-01-01

    Root morphology and Zn2+ uptake kinetics of the hyperaccumulating ecotype (HE) and nonhyperaccumulating ecotype (NHE) of Sedum alfredii Hance were investigated using hydroponic methods and the radiotracer flux technique. The results indicate that root length, root surface area, and root volume of NHE decreased significantly with increasing Zn2+ concentration in growth media, whereas the root growth of HE was not adversely affected, and was even promoted, by 500 μmol/L Zn2+. The concentrations of Zn2+ in both ecotypes of S. alfredii were positively correlated with root length, root surface area and root volumes, but no such correlation was found for root diameter. The uptake kinetics for 65Zn2+ in roots of both ecotypes of S. alfredii were characterized by a rapid linear phase during the first 6 h and a slower linear phase during the subsequent period of investigation. The concentration-dependent uptake kinetics of the two ecotypes of S. alfredii could be characterized by the Michaelis-Menten equation, with the Vmax for 65Zn2+ influx being threefold greater in HE compared with NHE, indicating that enhanced absorption into the root was one of the mechanisms involved in Zn hyperaccumulation. A significantly larger Vmax value suggested that there was a higher density of Zn transporters per unit membrane area in HE roots.

  13. Molecular and dendrochronological analysis of natural root grafting in Populus tremuloides (Salicaceae).

    Science.gov (United States)

    Jelínková, Hana; Tremblay, Francine; Desrochers, Annie

    2009-08-01

    Trembling aspen (Populus tremuloides) is a clonal tree species, which regenerates mostly through root suckering. In spite of vegetative propagation, aspen maintains high levels of clonal diversity. We hypothesized that the maintenance of clonal diversity in this species can be facilitated by integrating different clones through natural root grafts into aspen's communal root system. To verify this hypothesis, we analyzed root systems of three pure aspen stands where clones had been delineated with the help of molecular markers. Grafting between roots was frequent regardless of their genotypes. Root system excavations revealed that many roots were still living below trees that had been dead for several years. Some of these roots had no root connections other than grafts to living ramets of different clones. The uncovered root systems did not include any unique genotypes that would not occur among stems. Nevertheless, acquiring roots of dead trees helps to maintain extensive root systems, which increases the chances of clone survival. Substantial interconnectivity within clones as well as between clones via interclonal grafts results in formation of large genetically diverse physiological units. Such a clonal structure can significantly affect interpretations of diverse ecophysiological processes in forests of trembling aspen. PMID:21628295

  14. Seasonal Induction of Cluster Roots in Embothrium coccineum J.R. Forst. & G. Forst. in the Field: Factors that Regulate their Development Inducción Estacional de Raíces Proteoideas en Embothrium coccineum J.R. Forst. & G. Forst. en el Campo: Factores que Regulan su Desarrollo

    Directory of Open Access Journals (Sweden)

    Gabriel Donoso-Ñanculao

    2010-12-01

    Full Text Available Embothrium coccineum J.R. Forst. & G. Forst. (Proteaceae is a tree that grows successfully in nutrient poor soils of southern Chile at full sunlight. Under these conditions it develops cluster roots (CR.However, the induction of CR on this species has not been studied completely. The aim of this work was to study the effect of seasonality, soil and weeds in the development of CR in E. coccineum. The present study was performed in Los Lagos Region (41º72’ S lat, Chile. Plants of E. coccineum were grown in sandy soils in presence or absence of weeds, using two concentrations of organic matter. The number of CR per plant, CR mass and P concentration in leaves was measured during the four seasons in E. coccineum plants. The CR development in the soil with high organic matter concentration and without weeds was observed in autumn, spring and summer, and in the soil with low organic matter concentration was observed in autumn, winter and spring. Not found related of this result with the foliar P concentration in E. coccineum. The results suggest a strong seasonal and weeds effect on CR development in E. coccineum under field conditions.Embothrium coccineum J.R. Forst. & G. Forst.(Proteaceae es un árbol que crece en suelos pobres en nutrientes del sur de Chile a pleno sol. En estas condiciones desarrolla raíces proteoideas. Sin embargo, la inducción de raíces proteoideas en esta especie no ha sido estudiada completamente. El objetivo de este trabajo fue estudiar el efecto de la estacionalidad, suelo y malezas en el desarrollo de las raíces proteoideas en E. coccineum. El presente estudio fue desarrollado en la Región de Los Lagos (41º72' lat. S, Chile. Las plantas se cultivaron en suelo arenoso en presencia o ausencia de malezas, utilizando dos concentraciones de materia orgánica. El número de raíces proteoideas por planta, el peso de las raíces proteoideas y la concentración de P foliar, se midieron durante las cuatro estaciones en

  15. An Energy Distance Aware Clustering Protocol with Dual Cluster Heads Using Niching Particle Swarm Optimization for Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Dexin Ma

    2015-01-01

    Full Text Available Energy efficient utilization is an important criteria and factor that affects the design of wireless sensor networks (WSNs. In this literature, we propose an energy distance aware clustering protocol with Dual Cluster Heads using Niching Particle Swarm Optimization (DCH-NPSO. The protocol selects two cluster heads in each cluster, the Master Cluster Head (MCH and the Slave Cluster Head (SCH, and the selection needs to consider the network state information carefully and deliberately. Simulation results show that the protocol we proposed can balance the energy dissipation and extend the network lifetime effectively.

  16. Properties of Estimated Characteristic Roots

    DEFF Research Database (Denmark)

    Nielsen, Bent; Nielsen, Heino Bohn

    Estimated characteristic roots in stationary autoregressions are shown to give rather noisy information about their population equivalents. This is remarkable given the central role of the characteristic roots in the theory of autoregressive processes. In the asymptotic analysis the problems appear...

  17. Analyses of Disrupted Supply Chains by the Great East Japan Earthquake and Reconstruction of the Disaster-affected Region by the Cluster of the Automotive Industry: Utilizing the regional CGE model (Japanese)

    OpenAIRE

    Tokunaga, Suminori; Okiyama, Mitsuru; Akune, Yuko

    2013-01-01

    The purpose of this paper is first to analyze a negative supply shock due to "disrupted supply chains" caused by the earthquake and, secondly, to examine which of the policies to reconstruct the disaster-affected region is the most advisable way to proceed with the accumulation of the automotive industry. Using the two-regional computable general equilibrium (CGE) model, we initially found that had the alternative production at other plants been very easy, even if the production volume of mot...

  18. Effects of root herbivory on pyrrolizidine alkaloid content and aboveground plant-herbivore-parasitoid interactions in Jacobaea vulgaris

    OpenAIRE

    O. Kostenko; Mulder, P.P.J.; Bezemer, T.M.

    2013-01-01

    The importance of root herbivory is increasingly recognized in ecological studies, and the effects of root herbivory on plant growth, chemistry, and performance of aboveground herbivores have been relatively well studied. However, how belowground herbivory by root feeding insects affects aboveground parasitoid development is largely unknown. In this study, we examined the effects of root herbivory by wireworms (Agriotes lineatus) on the expression of primary and secondary compounds in the lea...

  19. Patterns in root traits of woody species hosting arbuscular and ectomycorrhizas: implications for the evolution of belowground strategies

    OpenAIRE

    Comas, Louise H; Callahan, Hilary S.; Midford, Peter E.

    2014-01-01

    Root traits vary enormously among plant species but we have little understanding of how this variation affects their functioning. Of central interest is how root traits are related to plant resource acquisition strategies from soil. We examined root traits of 33 woody species from northeastern US forests that form two of the most common types of mutualisms with fungi, arbuscular mycorrhizas (AM) and ectomycorrhizas (EM). We examined root trait distribution with respect to plant phylogeny, qua...

  20. Cluster number counts dependence on dark energy inhomogeneities and coupling to dark matter

    OpenAIRE

    M. Manera; Mota, D. F.

    2005-01-01

    Cluster number counts can be used to test dark energy models. We investigate dark energy candidates which are coupled to dark matter. We analyze the cluster number counts dependence on the amount of dark matter coupled to dark energy. Further more, we study how dark energy inhomogeneities affect cluster abundances. It is shown that increasing the coupling reduces significantly the cluster number counts, and that dark energy inhomogeneities increases cluster abundances. Wiggles in cluster numb...

  1. Dipole oscillation modes in $\\alpha$-clustering light nuclei

    CERN Document Server

    He, W B; Cao, X G; Cai, X Z; Zhang, G Q

    2016-01-01

    The alpha cluster states are discussed in an extended quantum molecular dynamics (EQMD) model frame. Different alpha cluster structures are studied in details, such as $^8$Be two-alpha cluster structure, $^{12}$C triangle structure, $^{12}$C chain structure, $^{16}$O chain structure, $^{16}$O kite structure, and $^{16}$O square structure. The properties like width of wave packets for different alpha clusters, momentum distribution, and the binding energy among alpha clusters are studied. It is also discussed how the $\\alpha$ cluster degree of freedom affects nuclear collective vibrations. The different $\\alpha$ cluster configurations in $^{12}$C and $^{16}$O have corresponding characteristic spectra of GDR and the coherence of different alpha clusters's dipole oscillation are described in details. The number and centroid energies of peaks in the GDR spectra can be reasonably explained by the geometrical and dynamical symmetries of $\\alpha$-clustering configurations. The GDR can be regarded as a very effective...

  2. Atomically precise cluster catalysis towards quantum controlled catalysts

    International Nuclear Information System (INIS)

    Catalysis of atomically precise clusters supported on a substrate is reviewed in relation to the type of reactions. The catalytic activity of supported clusters has generally been discussed in terms of electronic structure. Several lines of evidence have indicated that the electronic structure of clusters and the geometry of clusters on a support, including the accompanying cluster-support interaction, are strongly correlated with catalytic activity. The electronic states of small clusters would be easily affected by cluster–support interactions. Several studies have suggested that it is possible to tune the electronic structure through atomic control of the cluster size. It is promising to tune not only the number of cluster atoms, but also the hybridization between the electronic states of the adsorbed reactant molecules and clusters in order to realize a quantum-controlled catalyst. (review)

  3. Intercropping effect on root growth and nitrogen uptake at different nitrogen levels

    DEFF Research Database (Denmark)

    Ramirez-Garcia, Javier; Martens, Helle Juel; Quemada, Miguel;

    2015-01-01

    Aims Intercropping legumes and non-legumes may affect the root growth of both components in the mixture, and the non-legume is known to be strongly favored by increasing nitrogen (N) supply. The knowledge of how root systems affect the growth of the individual species is useful for understanding...... the interactions in intercrops as well as for planning cover cropping strategies. The aim of this work was (i) to determine if different levels of N in the topsoil influence root depth (RD) and intensity of barley and vetch as sole crops or as an intercropped mixture and (ii) to test if the choice of...... a mixture or the N availability in the topsoil will influence the N uptake by deep roots.Methods In this study, we combined rhizotron studies with root extraction and species identification by microscopy with studies of growth, N uptake and 15N uptake from deeper soil layers, for studying the root...

  4. Root water potential integrates discrete soil physical properties to influence ABA signalling during partial rootzone drying.

    Science.gov (United States)

    Dodd, Ian C; Egea, Gregorio; Watts, Chris W; Whalley, W Richard

    2010-08-01

    To investigate the influence of different growing substrates (two mineral, two organic) on root xylem ABA concentration ([ABA](root)) and the contribution of the drying root system to total sap flow during partial rootzone drying (PRD), sunflower (Helianthus annuus L.) shoots were grafted onto the root systems of two plants grown in separate pots. Sap flow through each hypocotyl was measured below the graft union when one pot ('wet') was watered and other ('dry') was not. Each substrate gave unique relationships between dry pot matric potential (Psi(soil)), volumetric water content ((v)) or penetrometer resistance (Q) and either the fraction of photoperiod sap flow from roots in drying soil or [ABA](root). However, decreased relative sap flow, and increased [ABA](root), from roots in drying soil varied with root water potential (Psi(root)) more similarly across a range of substrates. The gradient between Psi(soil) and Psi(root) was greater in substrates with high sand or peat proportions, which may have contributed to a more sensitive response of [ABA](root) to Psi(soil) in these substrates. Whole plant transpiration was most closely correlated with the mean Psi(soil) of both pots, and then with detached leaf xylem ABA concentration. Although Psi(root) best predicted decreased relative sap flow, and increased [ABA](root), from roots in drying soil across a range of substrates, the inaccessibility of this variable in field studies requires a better understanding of how measurable soil variables (Psi(soil), (v), Q) affect Psi(root). PMID:20591896

  5. Learning predictive clustering rules

    OpenAIRE

    Ženko, Bernard; Džeroski, Sašo; Struyf, Jan

    2005-01-01

    The two most commonly addressed data mining tasks are predictive modelling and clustering. Here we address the task of predictive clustering, which contains elements of both and generalizes them to some extent. We propose a novel approach to predictive clustering called predictive clustering rules, present an initial implementation and its preliminary experimental evaluation.

  6. Clustering of correlated networks

    OpenAIRE

    Dorogovtsev, S. N.

    2003-01-01

    We obtain the clustering coefficient, the degree-dependent local clustering, and the mean clustering of networks with arbitrary correlations between the degrees of the nearest-neighbor vertices. The resulting formulas allow one to determine the nature of the clustering of a network.

  7. Structures of Mn clusters

    Indian Academy of Sciences (India)

    Tina M Briere; Marcel H F Sluiter; Vijay Kumar; Yoshiyuki Kawazoe

    2003-01-01

    The geometries of several Mn clusters in the size range Mn13–Mn23 are studied via the generalized gradient approximation to density functional theory. For the 13- and 19-atom clusters, the icosahedral structures are found to be most stable, while for the 15-atom cluster, the bcc structure is more favoured. The clusters show ferrimagnetic spin configurations.

  8. Foodservice Occupations Cluster Guide.

    Science.gov (United States)

    Oregon State Dept. of Education, Salem.

    Intended to assist vocational teachers in developing and implementing a cluster program in food service occupations, this guide contains sections on cluster organization and implementation and instructional emphasis areas. The cluster organization and implementation section covers goal-based planning and includes a proposed cluster curriculum, a…

  9. Breeding of Root and Tuber Crops

    International Nuclear Information System (INIS)

    The root and tuber crops cassava, yams and sweet potato are important in Nigeria and Africa. Breeding methods most appropriate to these crops are discussed in terms of mating systems, creation of source populations, selections. Intervarietal hybridization, interspecific hybridization, and population improvement through cyclic selection and recombination procedures are methods of creating source populations. Factors affecting the effectiveness of selection, and efficient methods of selection to make maximum genetic progress are discussed. Use of selections is briefly stated. Synthetics, composites, or single and double crosses of yam produced from true seed may be used at the farmer level. (author)

  10. Auxin, the organizer of the environmental/hormonal signals for root hair growth

    Directory of Open Access Journals (Sweden)

    Hyung-Taeg eCho

    2013-11-01

    Full Text Available The root hair development is controlled by diverse factors such as fate-determining developmental cues, auxin-related environmental factors, and hormones. In particular, the soil environmental factors are important as they maximize their absorption by modulating root hair development. These environmental factors affect the root hair developmental process by making use of diverse hormones. These hormonal factors interact with each other to modulate root hair development in which auxin appears to form the most intensive networks with the pathways from environmental factors and hormones. Moreover, auxin action for root hair development is genetically located immediately upstream of the root hair-morphogenetic genes. These observations suggest that auxin plays as an organizing node for environmental/hormonal pathways to modulate root hair growth.

  11. Affective Computing and Sentiment Analysis

    CERN Document Server

    Ahmad, Khurshid

    2011-01-01

    This volume maps the watershed areas between two 'holy grails' of computer science: the identification and interpretation of affect -- including sentiment and mood. The expression of sentiment and mood involves the use of metaphors, especially in emotive situations. Affect computing is rooted in hermeneutics, philosophy, political science and sociology, and is now a key area of research in computer science. The 24/7 news sites and blogs facilitate the expression and shaping of opinion locally and globally. Sentiment analysis, based on text and data mining, is being used in the looking at news

  12. Relevant Subspace Clustering

    DEFF Research Database (Denmark)

    Müller, Emmanuel; Assent, Ira; Günnemann, Stephan; Krieger, Ralph; Seidl, Thomas

    Subspace clustering aims at detecting clusters in any subspace projection of a high dimensional space. As the number of possible subspace projections is exponential in the number of dimensions, the result is often tremendously large. Recent approaches fail to reduce results to relevant subspace...... clusters. Their results are typically highly redundant, i.e. many clusters are detected multiple times in several projections. In this work, we propose a novel model for relevant subspace clustering (RESCU). We present a global optimization which detects the most interesting non-redundant subspace clusters...... achieves top clustering quality while competing approaches show greatly varying performance....

  13. Tilting theory and cluster algebras

    OpenAIRE

    Reiten, Idun

    2010-01-01

    We give an introduction to the theory of cluster categories and cluster tilted algebras. We include some background on the theory of cluster algebras, and discuss the interplay with cluster categories and cluster tilted algebras.

  14. Medico-legal aspects of vertical root fractures in root filled teeth

    DEFF Research Database (Denmark)

    Rosen, E; Tsesis, I; Tamse, A;

    2012-01-01

    To analyse the medico-legal aspects of vertical root fracture (VRF) following root canal treatment (RCT).......To analyse the medico-legal aspects of vertical root fracture (VRF) following root canal treatment (RCT)....

  15. Affect Regulation

    DEFF Research Database (Denmark)

    Pedersen, Signe Holm; Poulsen, Stig Bernt; Lunn, Susanne

    2014-01-01

    Gergely and colleagues’ state that their Social Biofeedback Theory of Parental Affect Mirroring” can be seen as a kind of operationalization of the classical psychoanalytic concepts of holding, containing and mirroring. This article examines to what extent the social biofeedback theory of parenta...

  16. ROOTS - en totaloplevelsesevent

    OpenAIRE

    Boesen, Morten; Hjælmsø, Lea; Uhrbrand, Kirstine; Gyrsting Lorentzen, Christine; Bech Hansen, Ann Sophie

    2008-01-01

    The vision of this project is to re-launch Danish folk music through an event, where we focus on affecting all physical senses. The target group consists of young people between 15 and 25 years of age, and the event setting will be based on the their existing prejudice about the genre. Our hypothesis in this project is that the target groups’ perception of folk music is affected by their prejudices. Identification of the prejudices will be based on a focus group interview with members from th...

  17. Parallel Local Graph Clustering

    OpenAIRE

    Shun, Julian; Roosta-Khorasani, Farbod; Fountoulakis, Kimon; Mahoney, Michael W.

    2016-01-01

    Graph clustering has many important applications in computing, but due to growing sizes of graph, even traditionally fast clustering methods such as spectral partitioning can be computationally expensive for real-world graphs of interest. Motivated partly by this, so-called local algorithms for graph clustering have received significant interest due to the fact that they can find good clusters in a graph with work proportional to the size of the cluster rather than that of the entire graph. T...

  18. Clustering and classification

    CERN Document Server

    Arabie, Phipps

    1996-01-01

    At a moderately advanced level, this book seeks to cover the areas of clustering and related methods of data analysis where major advances are being made. Topics include: hierarchical clustering, variable selection and weighting, additive trees and other network models, relevance of neural network models to clustering, the role of computational complexity in cluster analysis, latent class approaches to cluster analysis, theory and method with applications of a hierarchical classes model in psychology and psychopathology, combinatorial data analysis, clusterwise aggregation of relations, review

  19. Cluster ion beam facilities

    International Nuclear Information System (INIS)

    A brief state-of-the-art review in the field of cluster-surface interactions is presented. Ionised cluster beams could become a powerful and versatile tool for the modification and processing of surfaces as an alternative to ion implantation and ion assisted deposition. The main effects of cluster-surface collisions and possible applications of cluster ion beams are discussed. The outlooks of the Cluster Implantation and Deposition Apparatus (CIDA) being developed in Guteborg University are shown

  20. Graded cluster algebras

    OpenAIRE

    Grabowski, Jan

    2015-01-01

    In the cluster algebra literature, the notion of a graded cluster algebra has been implicit since the origin of the subject. In this work, we wish to bring this aspect of cluster algebra theory to the foreground and promote its study. We transfer a definition of Gekhtman, Shapiro and Vainshtein to the algebraic setting, yielding the notion of a multi-graded cluster algebra. We then study gradings for finite type cluster algebras without coefficients, giving a full classification. Translating ...

  1. Root stimulated nitrogen removal: only a local effect or important for water treatment?

    Science.gov (United States)

    Münch, Ch; Kuschk, P; Röske, I

    2005-01-01

    Plants in constructed wetlands serve as carriers for attached microbial growth. They mainly transfer oxygen and release exsudates to the root zone. In consequence of this an area around the roots, called the rhizosphere exists, in which bacteria are stimulated by root growth. The goals were to ascertain whether stimulating the microbial cenosis only has a local effect on the rhizoplane, and to establish the importance of this stimulation for the water purification process in the root zone. Observations were carried out in a laboratory batch reactor filled with sand and planted with reeds (Phragmites australis). A small section was separated with gauze to avoid root growth outside this zone. The reactor was incubated with an artificial waste water containing a high concentration of ammonium. Samples were taken at intervals of 10 mm away from the gauze. The chemical and physical conditions and enzyme activities in soil sections at different distances from the roots affecting the efficiency of nitrogen removal were characterized. An influence was detectable by several parameters up to a specific root distance. Indirect parameters such as the total bacterial number and the DNA amount seem to be affected up to a distance of 50 mm from the root whereas the oxygen amount and DOC are unaffected at a distance exceeding 20-30 mm. This is an initial indication that improved nitrogen removal is also possible in the wider root surroundings. In view of the average root-to-root distance of 35 mm, the root-influenced area could therefore be expanded to the whole rooted zone in a constructed wetland. The influence on bacteria by roots is not just a local effect but may also play an important role in the whole purification process. PMID:16042258

  2. Clusters in strong laser fields: Comparison between carbon, platinum, and lead clusters

    Science.gov (United States)

    Schumacher, M.; Teuber, S.; Köller, L.; Köhn, J.; Tiggesbäumker, J.; Meiwes-Broer, K. H.

    Carbon and metal clusters are excited by strong femtosecond laser pulses with up to 1016 W/cm2, yielding ionized clusters and highly charged atomic ions. For small carbon clusters and fullerenes the abundance of charged species correlates with the laser power, while for metal clusters the ionization efficiency is additionally strongly affected by the chosen laser pulse width which may result in an enhanced up-charging of the metal particle. In the case of platinum atomic charge states up to z=20 are detected at a pulse duration of about 600 fs. This observation is in accordance with a model based on a multi-plasmon excitation process.

  3. Root anatomical phenes predict root penetration ability and biomechanical properties in maize (Zea Mays)

    OpenAIRE

    Chimungu, Joseph G.; Loades, Kenneth W.; Lynch, Jonathan P.

    2015-01-01

    The ability of roots to penetrate hard soil is important for crop productivity but specific root phenes contributing to this ability are poorly understood. Root penetrability and biomechanical properties are likely to vary in the root system dependent on anatomical structure. No information is available to date on the influence of root anatomical phenes on root penetrability and biomechanics. Root penetration ability was evaluated using a wax layer system. Root tensile and bending strength we...

  4. Cluster Evaluation of Density Based Subspace Clustering

    CERN Document Server

    Sembiring, Rahmat Widia

    2010-01-01

    Clustering real world data often faced with curse of dimensionality, where real world data often consist of many dimensions. Multidimensional data clustering evaluation can be done through a density-based approach. Density approaches based on the paradigm introduced by DBSCAN clustering. In this approach, density of each object neighbours with MinPoints will be calculated. Cluster change will occur in accordance with changes in density of each object neighbours. The neighbours of each object typically determined using a distance function, for example the Euclidean distance. In this paper SUBCLU, FIRES and INSCY methods will be applied to clustering 6x1595 dimension synthetic datasets. IO Entropy, F1 Measure, coverage, accurate and time consumption used as evaluation performance parameters. Evaluation results showed SUBCLU method requires considerable time to process subspace clustering; however, its value coverage is better. Meanwhile INSCY method is better for accuracy comparing with two other methods, altho...

  5. Shoot and root dry weight in drought exposed tomato populations

    Directory of Open Access Journals (Sweden)

    Brdar-Jokanović Milka

    2014-01-01

    Full Text Available This research was conducted with the aim to among forty-one tested tomato (Lycopersicon esculentum Mill populations distinguish those tolerant to limited water supply. Tolerance assessments were performed by using sixteen drought stress selection indices calculated on the basis of tomato shoot and root dry weight yields determined at water stress and non-stress conditions. Populations were differentiated in groups using the method of cluster analysis. The pot experiment was set in controlled greenhouse conditions and comprised optimally irrigated control and drought treatment (35.0 and 20.9% volumetric soil water content, respectively, imposed at the phase of intensive vegetative growth. The experiment was conducted at the Institute for Vegetable Crops in Smederevska Palanka, Serbia. The analyzed tomatoes exhibited significant differences in terms of response to limited irrigation, which had more pronounced effect on shoot dry weight than on the roots (average decrease of 64.4 and 35.7%, respectively. Consequently, root fraction in the total dry weight increased at drought for 68.2% on average. Shoot and root dry weights were positively correlated at optimal irrigation but not in drought, implying genotypic differences in terms of root adjustments to stress conditions. As for the calculated selection indices, substantial variation was found among the populations enabling their ranking in terms of drought tolerance. Since ranking was not the same in all cases, clustering the populations was performed taking into account all sixteen selection indices. The results of this analysis indicate that populations designated with numbers 126, 124, 131, 125, 128, 105, 101, 138, 110, 132 and 109 in Institute for Vegetable Crops germplasm collection exhibit satisfactory level of drought tolerance at vegetative phase and therefore may be used as parents in breeding programs. [Projekat Ministarstva nauke Republike Srbije, br. TR 31005 i br. TR 31059

  6. Root development during soil genesis: effects of root-root interactions, mycorrhizae, and substrate

    Science.gov (United States)

    Salinas, A.; Zaharescu, D. G.

    2015-12-01

    A major driver of soil formation is the colonization and transformation of rock by plants and associated microbiota. In turn, substrate chemical composition can also influence the capacity for plant colonization and development. In order to better define these relationships, a mesocosm study was set up to analyze the effect mycorrhizal fungi, plant density and rock have on root development, and to determine the effect of root morphology on weathering and soil formation. We hypothesized that plant-plant and plant-fungi interactions have a stronger influence on root architecture and rock weathering than the substrate composition alone. Buffalo grass (Bouteloua dactyloides) was grown in a controlled environment in columns filled with either granular granite, schist, rhyolite or basalt. Each substrate was given two different treatments, including grass-microbes and grass-microbes-mycorrhizae and incubated for 120, 240, and 480 days. Columns were then extracted and analyzed for root morphology, fine fraction, and pore water major element content. Preliminary results showed that plants produced more biomass in rhyolite, followed by schist, basalt, and granite, indicating that substrate composition is an important driver of root development. In support of our hypothesis, mycorrhizae was a strong driver of root development by stimulating length growth, biomass production, and branching. However, average root length and branching also appeared to decrease in response to high plant density, though this trend was only present among roots with mycorrhizal fungi. Interestingly, fine fraction production was negatively correlated with average root thickness and volume. There is also slight evidence indicating that fine fraction production is more related to substrate composition than root morphology, though this data needs to be further analyzed. Our hope is that the results of this study can one day be applied to agricultural research in order to promote the production of crops

  7. Media Clusters and Media Cluster Policies

    OpenAIRE

    Karlsson, Charlie; Picard, Robert

    2011-01-01

    Large media clusters have emerged in a limited number of large cities, characterizing the geographical concentration of the global media industry. This paper explores the reasons behind the localization patterns of media industries, the effect of the rapid advancement of Information and Communication Technologies (ICT) on media clusters and the role of media cluster policies. One might draw the conclusion that with the developments of the ICT sector and the fact that there are no raw material...

  8. Affective Urbanism

    DEFF Research Database (Denmark)

    Samson, Kristine

    , experience and consumption are all strategic design tools applied by planners and architects. Whereas urban design in former modernist planning served merely functional or political means, urban design has increasingly become an aesthetical mediator of ideologies embedded in the urban field of life forces...... capitalism not only changes urban life and its means of production, it specifically influences the way the city is designed and how it unfolds as events (Anderson & Harrison 2010) and affective, emotional production (Pile 2009). Through examples of urban design and events in the Carlsberg City in Copenhagen...... and The High Line in Chelsea, New York, the paper sets out to define and question these affective modes of production. Whether these productions are socio-material practices consisting of ludic designs (Stevens 2007), temporary architecture or art installations or evental practices consisting of...

  9. Cluster selection in divisive clustering algorithms

    OpenAIRE

    Savaresi, Sergio,; Boley, Daniel L.; Bittanti, Sergio; Gazzaniga, Giovanna

    2002-01-01

    This paper deals with the problem of clustering a data-set. In particular, the bisecting divisive approach is here considered. This approach can be naturally divided into two sub-problems: the problem of choosing which cluster must be divided, and the problem of splitting the selected cluster. The focus here is on the first problem. The contribution of this work is to propose a new technique for the selection of the cluster to split. This technique is based upon the shape of...

  10. Comprehensive analysis of Panax ginseng root transcriptomes

    OpenAIRE

    Jayakodi, Murukarthick; Lee, Sang-Choon; Lee, Yun Sun; Park, Hyun-Seung; Kim, Nam-Hoon; Jang, Woojong; Lee, Hyun Oh; Joh, Ho Jun; Yang, Tae-Jin

    2015-01-01

    Background Korean ginseng (Panax ginseng C.A. Meyer) is a highly effective medicinal plant containing ginsenosides with various pharmacological activities, whose roots are produced commercially for crude drugs. Results Here, we used the Illumina platform to generate over 232 million RNA sequencing reads from four root samples, including whole roots from one-year-old plants and three types of root tissue from six-year-old plants (i.e., main root bodies, rhizomes, and lateral roots). Through de...

  11. Evaluation of the post-operative lumbar spine with MR imaging. The role of contrast enhancement and thickening in nerve roots

    International Nuclear Information System (INIS)

    Purpose: Two new signs of lumbar nerve-root affection have been reported in recent years on the basis of MR examinations, namely: thickening in nerve roots; and contrast enhancement in nerve roots. The aim of this study was to assess contrast enhancement in nerve roots in a standardised way, and to evaluate the clinical significance of contrast enhancement and of nerve-root thickening in the symptomatic post-operative lumbar spine. Material and Methods: A total of 121 patients (who had previously been operated on for lumbar disc herniation) underwent 152 MR examinations, mainly on a 1.5 T system. Focal nerve-root enhancement was identified by visual assessment. Intradural enhancement was also quantified by pixel measurements that compared the affected nerve roots before and after contrast administration. Non-affected nerve roots were used as reference. Results: Enhanced nerve roots in the dural sac increased at least 40-50% in signal intensity after contrast administration compared to pre-contrast images and also compared to non-affected nerve roots. Intradural nerve-root enhancement was seen in 10% of the patients and focal enhancement in the root sleeve was seen in a further 26%. Nerve-root thickening was seen in 30%. Good correlation with clinical symptoms was found in 59% of the patients with intradural enhancement, in 84% with focal enhancement, and in 86% with nerve-root thickening. The combination of thickening and enhancement in the nerve root correlated with symptoms in 86% of the patients. Conclusion: Nerve-root enhancement (whether focal or intradural) and thickening in the nerve root are significant MR findings in the post-operative lumbar spine. In conbination with disc herniation or nerve-root displacement, these two signs may strengthen the indication for repeat surgery. However, root enhancement within 6 months of previous surgery may be a normal post-operative finding. (orig.)

  12. INDUSTRIAL ENGINEERING : ROOTING FOR ROOTS, HANKERING FOR HEROES

    OpenAIRE

    P.S. Kruger

    2012-01-01

    ENGLISH ABSTRACT: The “roots” of Industrial Engineering are certainly extensive, diverse and deep. Similarly, there are numerous historical “heroes” that made significant contributions to the development of the Industrial Engineering discipline. For the sake of argument, this article will assume that Industrial Engineering has at least two identifiable main roots, namely Determinism and Stochastism. The article attempts to trace the early history1 of the stochastic root which is very...

  13. Root pruning reduces root competition in living mulch cropping systems

    OpenAIRE

    Båth, B.; Kristensen, Hanne Lakkenborg; Thorup-Kristensen, Kristian

    2009-01-01

    In intercropping systems with a cash crop and a living mulch intercrop, competition between the cash crop and the intercrop (the living mulch) often reduces the yield of the cash crop. This project investigated (1) the influence of root pruning of living mulches on aboveground biomass of white cabbage. Below-ground growth and competition were examined by measuring (2) root distribution in minirhizotrons and (3) uptake of 15N placed at different soil depths. Two field experiments were carried ...

  14. Plant root-microbe communication in shaping root microbiomes

    OpenAIRE

    Lareen, Andrew; Burton, Frances; Schäfer, Patrick

    2016-01-01

    A growing body of research is highlighting the impacts root-associated microbial communities can have on plant health and development. These impacts can include changes in yield quantity and quality, timing of key developmental stages and tolerance of biotic and abiotic stresses. With such a range of effects it is clear that understanding the factors that contribute to a plant-beneficial root microbiome may prove advantageous. Increasing demands for food by a growing human population increase...

  15. Hypocotyl adventitious root organogenesis differs from lateral root development

    Directory of Open Access Journals (Sweden)

    Inge eVerstraeten

    2014-09-01

    Full Text Available Wound-induced adventitious root (AR formation is a requirement for plant survival upon root damage inflicted by pathogen attack, but also during the regeneration of plant stem cuttings for clonal propagation of elite plant varieties. Yet, adventitious rooting also takes place without wounding. This happens for example in etiolated Arabidopsis thaliana hypocotyls, in which AR initiate upon de-etiolation or in tomato seedlings, in which AR initiate upon flooding or high water availability. In the hypocotyl AR originate from a cell layer reminiscent to the pericycle in the primary root (PR and the initiated AR share histological and developmental characteristics with lateral roots (LR. In contrast to the PR however, the hypocotyl is a determinate structure with an established final number of cells. This points to differences between the induction of hypocotyl AR and LR on the PR, as the latter grows indeterminately. The induction of AR on the hypocotyl takes place in environmental conditions that differ from those that control LR formation. Hence, AR formation depends on differentially regulated gene products. Similarly to AR induction in stem cuttings, the capacity to induce hypocotyl AR is genotype-dependent and the plant growth regulator auxin is a key regulator controlling the rooting response. The hormones cytokinins, ethylene, jasmonic acid and strigolactones in general reduce the root-inducing capacity. The involvement of this many regulators indicates that a tight control and fine-tuning of the initiation and emergence of AR exists. Recently, several genetic factors, specific to hypocotyl adventitious rooting in Arabidopsis thaliana, have been uncovered. These factors reveal a dedicated signaling network that drives AR formation in the Arabidopsis hypocotyl. Here we provide an overview of the environmental and genetic factors controlling hypocotyl-born AR and we summarize how AR formation and the regulating factors of this organogenesis are

  16. Weeding Out the Roots of Involvement: Looking for a Hybrid.

    Science.gov (United States)

    Pokrywczynski, James; Fletcher, James

    The construct of involvement, used by marketers and consumer behaviorists for many years as a predictive measure of the qualitative relationship between an individual and a stimulus, has long been defined as having affective or cognitive roots. However, definitions that favor one or the other too heavily are less helpful because they are too…

  17. Root rots of common and tepary beans in Puerto Rico

    Science.gov (United States)

    Root rots are a disease complex affecting common bean and can be severe in bean growing areas in the tropics and subtropics. The presence of several pathogens makes it difficult to breed for resistance because of the synergistic effect of the pathogens in the host and the interaction of soil factors...

  18. Atmospheric Measurements of Neutral Nucleating Clusters (Invited)

    Science.gov (United States)

    Zhao, J.; Eisele, F. L.; Smith, J. N.; Chen, M.; Jiang, J.; Kuang, C.; McMurry, P. H.

    2010-12-01

    Nanoparticles produced by nucleation can subsequently grow to cloud condensation nuclei (CCN) within one or two days and hence affect cloud formation, precipitation, and atmospheric radiation budgets. As an intermediate stage between molecules and nanoparticles, neutral molecular clusters are believed to play an important role in processes that lead to boundary layer nucleation. Therefore, knowledge of chemical composition, concentrations, thermodynamic properties, and evolution of neutral molecular clusters is essential to better elucidate the nucleation mechanism and to reduce the uncertainty in nucleation rates used in global climate models. Here we present laboratory and field measurements from a recently developed chemical ionization mass spectrometer (the Cluster-CIMS) designed to measure atmospheric neutral clusters (Zhao et al., 2010). The sensitivity of the Cluster-CIMS was significantly improved by using a unique conical octopole device in the first vacuum stage for transmitting and focusing ions, which was further confirmed by ion trajectory simulations using SIMION. The ion cluster formation in the atmospheric-pressure inlet was controlled by two processes: neutral ionization and ion-induced clustering (IIC), which can be differentiated from the time independency of the intensity ratio between the cluster and monomer ions. Two methods were employed to separate neutral clusters from the ion-induced clustering. The concentrations and distribution of the neutral nucleating clusters containing up to 4 H2SO4 are estimated from the above methods at three measurement sites in the US (NCAR foothill laboratory, Manitou Forest Observatory, and Atlanta). Typically, the molecular cluster concentrations are well correlated with the concentrations of nanoparticles measured simultaneously during the nucleation event periods. The Cluster-CIMS was employed to measure clusters containing both sulfuric acid and amines in summer 2010 at NCAR foothill laboratory

  19. Young massive star clusters

    CERN Document Server

    Zwart, Simon Portegies; Gieles, Mark

    2010-01-01

    Young massive clusters are dense aggregates of young stars that form the fundamental building blocks of galaxies. Several examples exist in the Milky Way Galaxy and the Local Group, but they are particularly abundant in starburst and interacting galaxies. The few young massive clusters that are close enough to resolve are of prime interest for studying the stellar mass function and the ecological interplay between stellar evolution and stellar dynamics. The distant unresolved clusters may be effectively used to study the star-cluster mass function, and they provide excellent constraints on the formation mechanisms of young cluster populations. Young massive clusters are expected to be the nurseries for many unusual objects, including a wide range of exotic stars and binaries. So far only a few such objects have been found in young massive clusters, although their older cousins, the globular clusters, are unusually rich in stellar exotica. In this review we focus on star clusters younger than $\\sim100$\\,Myr, m...

  20. Testing chameleon gravity with the Coma cluster

    CERN Document Server

    Terukina, Ayumu; Yamamoto, Kazuhiro; Bacon, David; Koyama, Kazuya; Nichol, Robert C

    2013-01-01

    We propose a novel method to test the gravitational interactions in the outskirts of galaxy clusters. When gravity is modified, this is typically accompanied by an introduction of an additional scalar degree of freedom, which mediates an attractive fifth force. The presence of an extra gravitational coupling, however, is tightly constrained by local measurements. In chameleon modifications of gravity, local tests can be evaded by employing a screening mechanism that suppresses the fifth force in dense environments. While the chameleon field may be screened in the interior of the cluster, its outer region can still be affected by the extra force, introducing a deviation between the hydrostatic and lensing mass of the cluster. Thus, the chameleon modification can be tested by combining the gas and lensing measurements of the cluster. We demonstrate the operability of our method with the Coma cluster, for which both a lensing measurement and gas observations from the X-ray surface brightness, the X-ray temperatu...

  1. Towards a multidimensional root trait framework: a tree root review.

    Science.gov (United States)

    Weemstra, Monique; Mommer, Liesje; Visser, Eric J W; van Ruijven, Jasper; Kuyper, Thomas W; Mohren, Godefridus M J; Sterck, Frank J

    2016-09-01

    Contents 1159 I. 1159 II. 1161 III. 1164 IV. 1166 1167 References 1167 SUMMARY: The search for a root economics spectrum (RES) has been sparked by recent interest in trait-based plant ecology. By analogy with the one-dimensional leaf economics spectrum (LES), fine-root traits are hypothesised to match leaf traits which are coordinated along one axis from resource acquisitive to conservative traits. However, our literature review and meta-level analysis reveal no consistent evidence of an RES mirroring an LES. Instead the RES appears to be multidimensional. We discuss three fundamental differences contributing to the discrepancy between these spectra. First, root traits are simultaneously constrained by various environmental drivers not necessarily related to resource uptake. Second, above- and belowground traits cannot be considered analogues, because they function differently and might not be related to resource uptake in a similar manner. Third, mycorrhizal interactions may offset selection for an RES. Understanding and explaining the belowground mechanisms and trade-offs that drive variation in root traits, resource acquisition and plant performance across species, thus requires a fundamentally different approach than applied aboveground. We therefore call for studies that can functionally incorporate the root traits involved in resource uptake, the complex soil environment and the various soil resource uptake mechanisms - particularly the mycorrhizal pathway - in a multidimensional root trait framework. PMID:27174359

  2. Impact of treated wastewater on growth, respiration and hydraulic conductivity of citrus root systems in light and heavy soils.

    Science.gov (United States)

    Paudel, Indira; Cohen, Shabtai; Shaviv, Avi; Bar-Tal, Asher; Bernstein, Nirit; Heuer, Bruria; Ephrath, Jhonathan

    2016-06-01

    Roots interact with soil properties and irrigation water quality leading to changes in root growth, structure and function. We studied these interactions in an orchard and in lysimeters with clay and sandy loam soils. Minirhizotron imaging and manual sampling showed that root growth was three times lower in the clay relative to sandy loam soil. Treated wastewater (TWW) led to a large reduction in root growth with clay (45-55%) but not with sandy loam soil (system. The phenology and physiology of root orders were studied in lysimeters. Soil type influenced diameter, specific root area, tissue density and cortex area similarly in all root orders, while TWW influenced these only in clay soil. Respiration rates were similar in both soils, and root hydraulic conductivity was severely reduced in clay soil. Treated wastewater increased respiration rate and reduced hydraulic conductivity of all root orders in clay but only of the lower root orders in sandy loam soil. Loss of hydraulic conductivity increased with root order in clay and clay irrigated with TWW. Respiration and hydraulic properties of all root orders were significantly affected by sodium-amended TWW in sandy loam soil. These changes in root order morphology, anatomy, physiology and hydraulic properties indicate rapid and major modifications of root systems in response to differences in soil type and water quality. PMID:27022106

  3. Response of four cotton genotypes to N fertilization for root hydraulic conductance and lint yield

    Science.gov (United States)

    In controlled environments, hydraulic conductance of cotton (Gossypium hirsutum L.) roots is affected by nitrate supply. Limited information is available on the influence of N on cotton root hydraulic conductance under field conditions. The objective of this study was to determine the effect of N fe...

  4. Advances and considerations in technologies for growing, imaging, and analyzing 3-D root system architecture

    Science.gov (United States)

    The ability of a plant to mine the soil for nutrients and water is determined by how, where, and when roots are arranged in the soil matrix. The capacity of plant to maintain or improve its yield under limiting conditions, such as nutrient deficiency or drought, is affected by root system architectu...

  5. Postharvest respiration rate and sucrose content of Rhizoctonia-infected sugarbeet roots

    Science.gov (United States)

    Rhizotonia crown and root rot of sugarbeet, caused by Rhizoctonia solani AG 2-2, is increasing in Minnesota and North Dakota. As the disease increases in prevalence and severity, more diseased roots are being stored in piles where they affect storability and postharvest quality. The objective of th...

  6. Estimating Root Biomass and Distribution After Fire in a Great Basin Woodland Using Cores or Pits

    Science.gov (United States)

    Accurately estimating root biomass is critically important for understanding how below ground carbon storage is affected by different plant life forms and by fire. We compared a new soil coring technique with traditional quantitative pits for determining root biomass. We conducted the study in an ex...

  7. Monitoring cotton root rot progression within a growing season using airborne multispectral imagery

    Science.gov (United States)

    Cotton root rot, caused by the fungus Phymatotrichopsis omnivora, is a serious and destructive disease affecting cotton production in the southwestern United States. Accurate delineation of cotton root rot infections is important for cost-effective management of the disease. The objective of this st...

  8. Comparison of airborne multispectral and hyperspectral imagery for mapping cotton root rot

    Science.gov (United States)

    Cotton root rot, caused by the soilborne fungus, Phymatotrichum omnivorum, is a major cotton disease affecting cotton production in the southwestern and south central U.S. Accurate delineation of root rot infestations is necessary for cost-effective management of the disease. The objective of this s...

  9. Effects of Tomato Root Exudates on Meloidogyne incognita.

    Science.gov (United States)

    Yang, Guodong; Zhou, Baoli; Zhang, Xinyu; Zhang, Zijun; Wu, Yuanyuan; Zhang, Yiming; Lü, Shuwen; Zou, Qingdao; Gao, Yuan; Teng, Long

    2016-01-01

    Plant root exudates affect root-knot nematodes egg hatch. Chemicals in root exudates can attract nematodes to the roots or result in repellence, motility inhibition or even death. However, until recently little was known about the relationship between tomato root exudates chemicals and root-knot nematodes. In this study, root exudates were extracted from three tomato rootstocks with varying levels of nematode resistance: Baliya (highly resistant, HR), RS2 (moderately resistant, MR) and L-402 (highly susceptible, T). The effects of the root exudates on Meloidogyne incognita (M. incognita) egg hatch, survival and chemotaxis of second-stage juveniles (J2) were explored. The composition of the root exudates was analysed by gas chromatography/mass spectrometry (GC/MS) prior to and following M. incognita inoculation. Four compounds in root exudates were selected for further analysis and their allopathic effect on M. incognita were investigated. Root exudates from each tomato rootstocks (HR, MR and T strains) suppressed M. incognita egg hatch and increased J2 mortality, with the highest rate being observed in the exudates from the HR plants. Exudate from HR variety also repelled M. incognita J2 while that of the susceptible plant, T, was demonstrated to be attractive. The relative amount of esters and phenol compounds in root exudates from HR and MR tomato rootstocks increased notably after inoculation. Four compounds, 2,6-Di-tert-butyl-p-cresol, L-ascorbyl 2,6-dipalmitate, dibutyl phthalate and dimethyl phthalate increased significantly after inoculation. The egg hatch of M. incognita was suppressed by each of the compound. L-ascorbyl 2,6-dipalmitate showed the most notable effect in a concentration-dependent manner. All four compounds were associated with increased J2 mortality. The greatest effect was observed with dimethyl phthalate at 2 mmol·L-1. Dibutyl phthalate was the only compound observed to repel M. incognita J2 with no effect being detected in the other

  10. Effects of Tomato Root Exudates on Meloidogyne incognita.

    Directory of Open Access Journals (Sweden)

    Guodong Yang

    Full Text Available Plant root exudates affect root-knot nematodes egg hatch. Chemicals in root exudates can attract nematodes to the roots or result in repellence, motility inhibition or even death. However, until recently little was known about the relationship between tomato root exudates chemicals and root-knot nematodes. In this study, root exudates were extracted from three tomato rootstocks with varying levels of nematode resistance: Baliya (highly resistant, HR, RS2 (moderately resistant, MR and L-402 (highly susceptible, T. The effects of the root exudates on Meloidogyne incognita (M. incognita egg hatch, survival and chemotaxis of second-stage juveniles (J2 were explored. The composition of the root exudates was analysed by gas chromatography/mass spectrometry (GC/MS prior to and following M. incognita inoculation. Four compounds in root exudates were selected for further analysis and their allopathic effect on M. incognita were investigated. Root exudates from each tomato rootstocks (HR, MR and T strains suppressed M. incognita egg hatch and increased J2 mortality, with the highest rate being observed in the exudates from the HR plants. Exudate from HR variety also repelled M. incognita J2 while that of the susceptible plant, T, was demonstrated to be attractive. The relative amount of esters and phenol compounds in root exudates from HR and MR tomato rootstocks increased notably after inoculation. Four compounds, 2,6-Di-tert-butyl-p-cresol, L-ascorbyl 2,6-dipalmitate, dibutyl phthalate and dimethyl phthalate increased significantly after inoculation. The egg hatch of M. incognita was suppressed by each of the compound. L-ascorbyl 2,6-dipalmitate showed the most notable effect in a concentration-dependent manner. All four compounds were associated with increased J2 mortality. The greatest effect was observed with dimethyl phthalate at 2 mmol·L-1. Dibutyl phthalate was the only compound observed to repel M. incognita J2 with no effect being detected in

  11. Effects of Increased Summer Precipitation and Nitrogen Addition on Root Decomposition in a Temperate Desert.

    Directory of Open Access Journals (Sweden)

    Hongmei Zhao

    Full Text Available Climate change scenarios that include precipitation shifts and nitrogen (N deposition are impacting carbon (C budgets in arid ecosystems. Roots constitute an important part of the C cycle, but it is still unclear which factors control root mass loss and nutrient release in arid lands.Litterbags were used to investigate the decomposition rate and nutrient dynamics in root litter with water and N-addition treatments in the Gurbantunggut Desert in China. Water and N addition had no significant effect on root mass loss and the N and phosphorus content of litter residue. The loss of root litter and nutrient releases were strongly controlled by the initial lignin content and the lignin:N ratio, as evidenced by the negative correlations between decomposition rate and litter lignin content and the lignin:N ratio. Fine roots of Seriphidium santolinum (with higher initial lignin content had a slower decomposition rate in comparison to coarse roots.Results from this study indicate that small and temporary changes in rainfall and N deposition do not affect root decomposition patterns in the Gurbantunggut Desert. Root decomposition rates were significantly different between species, and also between fine and coarse roots, and were determined by carbon components, especially lignin content, suggesting that root litter quality may be the primary driver of belowground carbon turnover.

  12. Carbon and nitrogen status of decomposing roots in three adjacent coniferous plantations

    Directory of Open Access Journals (Sweden)

    Jaeyeob Jeong

    2014-07-01

    Full Text Available This study evaluated the carbon (C and nitrogen (N status of decomposing roots in three adjacent plantations consisting of one deciduous (larch: Larix leptolepis and two evergreen (red pine: Pinus densiflora; rigitaeda pine: P. rigitaeda species planted in the same year (1963 under similar site conditions. The mass loss rates and C and N status of three diameter classes of roots (UF < 2 mm, F 2-5 mm, CF 5-10 mm in diameter were examined in the upper 15 cm of the mineral soil using in situ buried root bags for 496 days.The remaining mass of decomposing roots was significantly higher for larch (69.0% than for red pine (59.6% or rigitaeda pine (59.1% over 496 days. The mass loss rates of decomposing roots did not differ significantly among the three root diameter classes, but the C and N status of decomposing roots was affected by the tree species. The larch roots showed low C concentrations but high N concentrations, C and N remaining compared to the pine roots over the study period. The results indicate that the substrate quality indicators of roots were not attributed to the mass loss rates, C and N status of decomposing roots in three coniferous tree species grown under similar environmental conditions.

  13. Auxin, ethylene and the regulation of root growth under mechanical impedance

    Science.gov (United States)

    Sharma, Rameshwar; Santisree, Parankusam; Nongmaithem, Sapana; Sreelakshmi, Yellamaraju

    2012-07-01

    Among the multitude functions performed by plant roots, little information is available about the mechanisms that allow roots to overcome the soil resistance, in order to grow in the soil to obtain water and nutrient. Tomato (Solanum lycopersicum) seedlings grown on horizontally placed agar plates showed a progressive decline in the root length with the increasing impedance of agar media. The incubation with 1-methylcyclopropane (1-MCP), an inhibitor of ethylene perception, led to aerial growth of roots. In contrast, in absence of 1-MCP control roots grew horizontally anchored to the agar surface. Though 1-MCP-treated and control seedlings showed differential ability to penetrate in the agar, the inhibition of root elongation was nearly similar for both treatments. While increased mechanical impedance also progressively impaired hypocotyl elongation in 1-MCP treated seedlings, it did not affect the hypocotyl length of control seedlings. The decline in root elongation was also associated with increased expression of DR5::GUS activity in the root tip signifying accumulation of auxin at the root tip. The increased expression of DR5::GUS activity in the root tip was also observed in 1-MCP treated seedlings, indicating independence of this response from ethylene signaling. Our results indicate operation of a sensing mechanism in root that likely operates independently of ethylene but involves auxin to determine the degree of impedance of the substratum.

  14. Cluster automorphism groups of cluster algebras with coefficients

    OpenAIRE

    Chang, Wen; Zhu, Bin

    2015-01-01

    We study the cluster automorphism group of a skew-symmetric cluster algebra with geometric coefficients. For this, we introduce the notion of gluing free cluster algebra, and show that under a weak condition the cluster automorphism group of a gluing free cluster algebra is a subgroup of the cluster automorphism group of its principal part cluster algebra (i.e. the corresponding cluster algebra without coefficients). We show that several classes of cluster algebras with coefficients are gluin...

  15. Root hairs improve root penetration, root-soil contact, and phosphorus acquisition in soils of different strength.

    Science.gov (United States)

    Haling, Rebecca E; Brown, Lawrie K; Bengough, A Glyn; Young, Iain M; Hallett, Paul D; White, Philip J; George, Timothy S

    2013-09-01

    Root hairs are a key trait for improving the acquisition of phosphorus (P) by plants. However, it is not known whether root hairs provide significant advantage for plant growth under combined soil stresses, particularly under conditions that are known to restrict root hair initiation or elongation (e.g. compacted or high-strength soils). To investigate this, the root growth and P uptake of root hair genotypes of barley, Hordeum vulgare L. (i.e. genotypes with and without root hairs), were assessed under combinations of P deficiency and high soil strength. Genotypes with root hairs were found to have an advantage for root penetration into high-strength layers relative to root hairless genotypes. In P-deficient soils, despite a 20% reduction in root hair length under high-strength conditions, genotypes with root hairs were also found to have an advantage for P uptake. However, in fertilized soils, root hairs conferred an advantage for P uptake in low-strength soil but not in high-strength soil. Improved root-soil contact, coupled with an increased supply of P to the root, may decrease the value of root hairs for P acquisition in high-strength, high-P soils. Nevertheless, this work demonstrates that root hairs are a valuable trait for plant growth and nutrient acquisition under combined soil stresses. Selecting plants with superior root hair traits is important for improving P uptake efficiency and hence the sustainability of agricultural systems. PMID:23861547

  16. Mangrove root communities in Jobos Bay

    International Nuclear Information System (INIS)

    Based on the presence and absence of species, at least two major types of mangrove root communities exist in Jobos Bay. One community, occurring mainly along the Aguirre Ship Channel, is composed of species characteristic of coastal waters. Another occurring in Jobos Bay and in mangrove channels in the vinicity of Mar Negro Lagoon is characterized by embayment species. Water mass is the best single parameter which correlates with the different communities. In general, subtidal species are more susceptible to elevated temperatures than intertidal species and consequently will be the first affected. Because most of the predators and competitors are subtidal, the predation and competition which limit populations may be cut back. The effect will first be seen in increased populations of barnacles, because they are severely limited by predation and competition but are physiologically quite tolerant. The intertidal species should flourish (on a relative basis) and their vertical distributions should be extended downward. These effects are only primary. Many species which would do best in thermally altered situations are colonizing or fugitive species. It is unknown whether such an assemblage could persist with continued recruitment and growth of new individuals. The dominance of these colonizing or fugitive species may be only temporary, however, because blue-green algae are tolerant of elevated temperatures and have a negative effect on barnacle recruitment and growth. Consequently, blue-green algae may eventually dominate thermally affected mangrove roots

  17. Bidirectional Agglomerative Hierarchical Clustering using AVL Tree Algorithm

    Directory of Open Access Journals (Sweden)

    Hussain Abu-Dalbouh

    2011-09-01

    Full Text Available The hierarchy is often used to infer knowledge from groups of items and relations in varying granularities. Hierarchical clustering algorithms take an input of pairwise data-item similarities and output a hierarchy of the data-items. This paper presents Bidirectional agglomerative hierarchical clustering to create a hierarchy bottom-up, by iteratively merging the closest pair of data-items into one cluster. The result is a rooted AVL tree. The n leafs correspond to input data-items (singleton clusters needs to n/2 or n/2+1 steps to merge into one cluster, correspond to groupings of items in coarser granularities climbing towards the root. As observed from the time complexity and number of steps need to cluster all data points into one cluster perspective, the performance of the bidirectional agglomerative algorithm using AVL tree is better than the current agglomerative algorithms. The experiment analysis results indicate that the improved algorithm has a higher efficiency than previous methods.

  18. What drives ICT clustering in European Cities?

    OpenAIRE

    Belitski, Maksim; Desai, S.

    2016-01-01

    ICT clusters have attracted much attention because of their rapid growth and their value for other economic activities. Using a nested multi-level model, we examine how conditions at the country level and at the city level affect ICT clustering activity in 227 cities across 22 European countries. We test for the influence of three country regulations (starting a business, registering property, enforcing contracts) and two city conditions (proximity to university, network density) on ICT clust...

  19. What Makes Clusters Decline?

    DEFF Research Database (Denmark)

    Østergaard, Christian Richter; Park, Eun Kyung

    2015-01-01

    Most studies on regional clusters focus on identifying factors and processes that make clusters grow. However, sometimes technologies and market conditions suddenly shift, and clusters decline. This paper analyses the process of decline of the wireless communication cluster in Denmark. The...... longitudinal study on the high-tech cluster reveals that technological lock-in and exit of key firms have contributed to decline. Entrepreneurship has a positive effect on the cluster’s adaptive capabilities, while multinational companies have contradicting effects by bringing in new resources to the cluster...

  20. Polyamine-Induced Rapid Root Abscission in Azolla pinnata

    Directory of Open Access Journals (Sweden)

    Sushma Gurung

    2012-01-01

    Full Text Available Floating ferns of the genus Azolla detach their roots under stress conditions, a unique adaptive response termed rapid root abscission. We found that Azolla pinnata plants exhibited dose-dependent rapid root abscission in response to the polyamines spermidine and spermine after a substantial time lag (>20 min. The duration of the time lag decreased in response to high pH and high temperature whereas high light intensity increased the time lag and markedly lowered the rate of abscission. The oxidation products of polyamines, 1,3-diaminopropane, β-alanine and hydrogen peroxide all failed to initiate root abscission, and hydroxyethyl hydrazine, an inhibitor of polyamine oxidase, did not inhibit spermine-induced root abscission. Exposure of A. pinnata to the polyamines did not result in detectable release of NO and did not affect nitrite-dependent NO production. The finding of polyamine-induced rapid root abscission provides a facile assay for further study of the mode of action of polyamines in plant stress responses.

  1. Polyamine-Induced Rapid Root Abscission in Azolla pinnata.

    Science.gov (United States)

    Gurung, Sushma; Cohen, Michael F; Fukuto, Jon; Yamasaki, Hideo

    2012-01-01

    Floating ferns of the genus Azolla detach their roots under stress conditions, a unique adaptive response termed rapid root abscission. We found that Azolla pinnata plants exhibited dose-dependent rapid root abscission in response to the polyamines spermidine and spermine after a substantial time lag (>20 min). The duration of the time lag decreased in response to high pH and high temperature whereas high light intensity increased the time lag and markedly lowered the rate of abscission. The oxidation products of polyamines, 1,3-diaminopropane, β-alanine and hydrogen peroxide all failed to initiate root abscission, and hydroxyethyl hydrazine, an inhibitor of polyamine oxidase, did not inhibit spermine-induced root abscission. Exposure of A. pinnata to the polyamines did not result in detectable release of NO and did not affect nitrite-dependent NO production. The finding of polyamine-induced rapid root abscission provides a facile assay for further study of the mode of action of polyamines in plant stress responses. PMID:22997568

  2. Cell Wall Heterogeneity in Root Development of Arabidopsis.

    Science.gov (United States)

    Somssich, Marc; Khan, Ghazanfar Abbas; Persson, Staffan

    2016-01-01

    Plant cell walls provide stability and protection to plant cells. During growth and development the composition of cell walls changes, but provides enough strength to withstand the turgor of the cells. Hence, cell walls are highly flexible and diverse in nature. These characteristics are important during root growth, as plant roots consist of radial patterns of cells that have diverse functions and that are at different developmental stages along the growth axis. Young stem cell daughters undergo a series of rapid cell divisions, during which new cell walls are formed that are highly dynamic, and that support rapid anisotropic cell expansion. Once the cells have differentiated, the walls of specific cell types need to comply with and support different cell functions. For example, a newly formed root hair needs to be able to break through the surrounding soil, while endodermal cells modify their walls at distinct positions to form Casparian strips between them. Hence, the cell walls are modified and rebuilt while cells transit through different developmental stages. In addition, the cell walls of roots readjust to their environment to support growth and to maximize nutrient uptake. Many of these modifications are likely driven by different developmental and stress signaling pathways. However, our understanding of how such pathways affect cell wall modifications and what enzymes are involved remain largely unknown. In this review we aim to compile data linking cell wall content and re-modeling to developmental stages of root cells, and dissect how root cell walls respond to certain environmental changes. PMID:27582757

  3. Piriformospora indica Stimulates Root Metabolism of Arabidopsis thaliana.

    Science.gov (United States)

    Strehmel, Nadine; Mönchgesang, Susann; Herklotz, Siska; Krüger, Sylvia; Ziegler, Jörg; Scheel, Dierk

    2016-01-01

    Piriformospora indica is a root-colonizing fungus, which interacts with a variety of plants including Arabidopsis thaliana. This interaction has been considered as mutualistic leading to growth promotion of the host. So far, only indolic glucosinolates and phytohormones have been identified as key players. In a comprehensive non-targeted metabolite profiling study, we analyzed Arabidopsis thaliana's roots, root exudates, and leaves of inoculated and non-inoculated plants by ultra performance liquid chromatography/electrospray ionization quadrupole-time-of-flight mass spectrometry (UPLC/(ESI)-QTOFMS) and gas chromatography/electron ionization quadrupole mass spectrometry (GC/EI-QMS), and identified further biomarkers. Among them, the concentration of nucleosides, dipeptides, oligolignols, and glucosinolate degradation products was affected in the exudates. In the root profiles, nearly all metabolite levels increased upon co-cultivation, like carbohydrates, organic acids, amino acids, glucosinolates, oligolignols, and flavonoids. In the leaf profiles, we detected by far less significant changes. We only observed an increased concentration of organic acids, carbohydrates, ascorbate, glucosinolates and hydroxycinnamic acids, and a decreased concentration of nitrogen-rich amino acids in inoculated plants. These findings contribute to the understanding of symbiotic interactions between plant roots and fungi of the order of Sebacinales and are a valid source for follow-up mechanistic studies, because these symbioses are particular and clearly different from interactions of roots with mycorrhizal fungi or dark septate endophytes. PMID:27399695

  4. Root activity evaluation in tree crops using isotopic techniques

    International Nuclear Information System (INIS)

    This paper discusses the methdology used to evalute root activity of the crops utilizing the technique of soil injection with solutions marked with isotopes. Some of the experimental data obtained with coffee, citrus and oil palm are also presented. Ovel all, these tree crops present a higher root activity in soil layers close to the surface (0-20 cm) and to a distance from the trunk which varies with age, season and variety. The most important conclusions are: 1. The isotope injection technique using 32P, 15N, or 85Rb, allow direct and reliable determination of root activity in these tree crops. 2. Root activity of three crops depends on age of the tree, variety, moisture content of the soil and soil type. 3. Soil moisture is the most influencial factor affecting root activity. This is turn depends on the irrigation method employed. 4. From the practical view point, the best distance from the trunk to apply fertilizer in the one wich has highest root activity closest to the soil surface

  5. Roots of mappings from manifolds

    Directory of Open Access Journals (Sweden)

    Brooks Robin

    2004-01-01

    Full Text Available Assume that is a proper map of a connected -manifold into a Hausdorff, connected, locally path-connected, and semilocally simply connected space , and has a neighborhood homeomorphic to Euclidean -space. The proper Nielsen number of at and the absolute degree of at are defined in this setting. The proper Nielsen number is shown to a lower bound on the number of roots at among all maps properly homotopic to , and the absolute degree is shown to be a lower bound among maps properly homotopic to and transverse to . When , these bounds are shown to be sharp. An example of a map meeting these conditions is given in which, in contrast to what is true when is a manifold, Nielsen root classes of the map have different multiplicities and essentialities, and the root Reidemeister number is strictly greater than the Nielsen root number, even when the latter is nonzero.

  6. Ultrasonic cleaning of root canals

    Science.gov (United States)

    Verhaagen, Bram; Boutsioukis, Christos; Jiang, Lei-Meng; Macedo, Ricardo; van der Sluis, Luc; Versluis, Michel

    2011-11-01

    A crucial step during a dental root canal treatment is irrigation, where an antimicrobial fluid is injected into the root canal system to eradicate all bacteria. Agitation of the fluid using an ultrasonically vibrating miniature file has shown significant improvement in cleaning efficacy over conventional syringe irrigation. However, the physical mechanisms underlying the cleaning process, being acoustic streaming, cavitation or chemical activity, and combinations thereof, are not fully understood. High-speed imaging allows us to visualize the flow pattern and cavitation in a root canal model at microscopic scales, at timescales relevant to the cleaning processes (microseconds). MicroPIV measurements of the induced acoustic streaming are coupled to the oscillation characteristics of the file as simulated numerically and measured with a laser vibrometer. The results give new insight into the role of acoustic streaming and the importance of the confinement for the cleaning of root canals.

  7. Affective Maps

    DEFF Research Database (Denmark)

    Salovaara-Moring, Inka

    Recently, in human geography there has been a considerable attention paid to retheorising maps; less as a product and more as practice. This refers to the notion that rather than reading maps as fixed representations, digital mapping is by nature a dynamic, performative, and participatory practice....... In particular, mapping environmental damage, endangered species, and human made disasters has become one of the focal point of affective knowledge production. These ‘more-than-humangeographies’ practices include notions of species, space and territory, and movement towards a new political ecology...

  8. Root Patterns in Heterogeneous Soils

    Science.gov (United States)

    Dara, A.; Moradi, A. B.; Carminati, A.; Oswald, S. E.

    2010-12-01

    Heterogeneous water availability is a typical characteristic of soils in which plant roots grow. Despite the intrinsic heterogeneity of soil-plant water relations, we know little about the ways how plants respond to local environmental quality. Furthermore, increasing use of soil amendments as partial water reservoirs in agriculture calls for a better understanding of plant response to soil heterogeneity. Neutron radiography is a non-invasive imaging that is highly sensitive to water and root distribution and that has high capability for monitoring spatial and temporal soil-plant water relations in heterogeneous systems. Maize plants were grown in 25 x 30 x 1 cm aluminum slabs filled with sandy soil. On the right side of the compartments a commercial water absorbent (Geohumus) was mixed with the soil. Geohumus was distributed with two patterns: mixed homogeneously with the soil, and arranged as 1-cm diameter aggregates (Fig. 1). Two irrigation treatments were applied: sufficient water irrigation and moderate water stress. Neutron radiography started 10 days after planting and has been performed twice a day for one week. At the end of the experiment, the containers were opened, the root were removed and dry root weight in different soil segments were measured. Neutron radiography showed root growth tendency towards Geohumus treated parts and preferential water uptake from Geohumus aggregates. Number and length of fine lateral roots were lower in treated areas compared to the non-treated zone and to control soil. Although corn plants showed an overall high proliferation towards the soil water sources, they decreased production of branches and fine root when water was more available near the main root parts. However there was 50% higher C allocation in roots grown in Geohumus compartments, as derived by the relative dry weight of root. The preferential C allocation in treated regions was higher when plants grew under water stress. We conclude that in addition to the

  9. Roots of unity in orders

    OpenAIRE

    Lenstra Jr., H. W.; Silverberg, A.

    2015-01-01

    We give deterministic polynomial-time algorithms that, given an order, compute the primitive idempotents and determine a set of generators for the group of roots of unity in the order. Also, we show that the discrete logarithm problem in the group of roots of unity can be solved in polynomial time. As an auxiliary result, we solve the discrete logarithm problem for certain unit groups in finite rings. Our techniques, which are taken from commutative algebra, may have further potential in the ...

  10. Roots of Quaternion Standard Polynomials

    CERN Document Server

    Chapman, Adam

    2011-01-01

    Here we present a reduction of any quaternion standard polynomial equation into an equation with two central variables and quaternion coefficients. If only pure imaginary roots are in demand, then the equation is with one central variable. As a result of this reduction we obtain formulas for the solutions of quadratic equations. Another result is a routine for analytically solving cubic quaternion equations assuming they have at least one pure imaginary root.

  11. Clustering Analysis on E-commerce Transaction Based on K-means Clustering

    Directory of Open Access Journals (Sweden)

    Xuan HUANG

    2014-02-01

    Full Text Available Based on the density, increment and grid etc, shortcomings like the bad elasticity, weak handling ability of high-dimensional data, sensitive to time sequence of data, bad independence of parameters and weak handling ability of noise are usually existed in clustering algorithm when facing a large number of high-dimensional transaction data. Making experiments by sampling data samples of the 300 mobile phones of Taobao, the following conclusions can be obtained: compared with Single-pass clustering algorithm, the K-means clustering algorithm has a high intra-class dissimilarity and inter-class similarity when analyzing e-commerce transaction. In addition, the K-means clustering algorithm has very high efficiency and strong elasticity when dealing with a large number of data items. However, clustering effects of this algorithm are affected by clustering number and initial positions of clustering center. Therefore, it is easy to show the local optimization for clustering results. Therefore, how to determine clustering number and initial positions of the clustering center of this algorithm is still the important job to be researched in the future.

  12. Frequency of the external resorptions of root apex

    Directory of Open Access Journals (Sweden)

    Opačić-Galić Vanja

    2004-01-01

    Full Text Available Root resorptions present a significant problem in endodontic therapy of the affected teeth and in dentistry in general. The objective of this study was to analyze, based on epidemiological and statistical research, the frequency of clinical incidence of pathological root resorptions in everyday practice related to localization, type of tooth, age and sex of patients. Radiographie documentation of patients treated from 1997 till 2002 at the Department of Conservative Dentistry and Endodontics, Faculty of Stomatology in Belgrade, was used as baseline for this study. Retroalveolar radiographs of teeth with visible signs of resorptions were singled out from 15654 patients' clinical records used for this study. The external resorptions were shown as radiolucent areas localized on various outer root surfaces, followed by significant or less significant resorption of lamina dura and alveolar bone. Out of all teeth analyzed in this study, 594 (3.79% showed some kind of resorption. The external resorptions were found to be more present in the upper jaw (55.10% and molars (50.30% than in the lower jaw (44.90% and single root teeth (49.70%, but in both cases without significant statistical differences. The most frequent localization of resorptions was root apex (82.44%. In regard to age, the most frequent resorptions were recorded in patients aged between 21 and 30 years (28.40%, and the lowest incidence was found in the youngest population (5.51%. The results also showed that resorptions were more frequent among the female population (59.04% than among the male population (40.96%. Based on these results, we may conclude that the external root resorptions are not a frequent clinical phenomenon. Proper and early diagnostics of such tissue pathology is one of the basic prerequisites for successful endodontic therapy of the affected root.

  13. Analysis of Various Clustering Algorithms

    OpenAIRE

    Asst Prof. Sunila Godara,; Ms. Amita Verma,

    2013-01-01

    Data clustering is a process of putting similar data into groups. A clustering algorithm partitions a data set into several groups such that the similarity within a group is larger than among groups. This paper reviews four types of clustering techniques- k-Means Clustering, Farther first clustering, Density Based Clustering, Filtered clusterer. These clustering techniques are implemented and analyzed using a clustering tool WEKA. Performance of the 4 techniques are presented and compared.

  14. Root hair mutants of barley

    International Nuclear Information System (INIS)

    Barley mutants without root hairs or with short or reduced root hairs were isolated among M2 seeds of 'Lux' barley (Hordeum vulgare L.) after acidified sodium azide mutagenesis. Root hair mutants are investigated intensively in Arabidopsis where about 40 genes are known. A few root hair mutants are known in maize, rice, barley and tomato. Many plants without root hairs grow quite well with good plant nutrition, and mutants have been used for investigations of uptake of strongly bound nutrients like phosphorus, iron, zinc and silicon. Seed of 'Lux' barley (Sejet Plant Breeding, Denmark) were soaked overnight, and then treated with 1.5-millimolarsodium azide in 0.1 molar sodium phosphate buffer, pH 3, for 2.5 hours according to the IAEA Manual on Mutation Breeding (2nd Ed.). After rinsing in tap water and air-drying, the M2 seeds were sown in the field the same day. Spikes, 4-6 per M1 plant, were harvested. The mutation frequency was similar to that obtained with other barley cultivars from which low-phytate mutants were isolated [5]. Seeds were germinated on black filter paper in tap water for 3 or 4 days before scoring for root hair mutants

  15. Driving factors for cluster development - Which kind of spatial rootedness and change?

    OpenAIRE

    Franz Tödtling; Alexander Auer; Tanja Sinozic

    2014-01-01

    Driving factors and mechanisms for cluster development have often been investigated based on the standard cluster approach as conceptualised e.g. by Michael Porter. These studies have revealed certain insights regarding the role of local entrepreneurship, factor conditions, demand, and related industries in supporting clusters. However, such factors were analysed often from a static competitiveness perspective, and they were often seen as rooted in a region or part of an overly ...

  16. Ecology and genetics of root architecture and soil water extraction

    International Nuclear Information System (INIS)

    Merging the study of plant ecophysiology and genetics has great potential for improving crops for stressful environments. Root systems play a key role in acquiring resources and stress avoidance, but they also represent a major cost to plants in terms of carbon expenditures. Additional allocation to roots potentially affects crop growth and yield, either positively in the case of stress avoidance, or negatively in situations where the costs of root allocation outweigh the benefits in yield. Knowledge of these relationships are necessary for optimizing plant breeding for root system characteristics, and suggest that breeding goals for root systems may vary by species, resource availability, and local agricultural environments. This research project focused on the deep acquisition of water by a vegetable crop from the soil profile, as a means to reduce water stress and irrigation inputs. The goal was to determine the type of root architectural system that was conducive to rapid shoot growth and deep soil water extraction in lettuce, a shallow-rooted crop with high water demand. Genes, i.e. Quantitative Trait Loci (QTL), for a deeper taproot and for more laterals at the tip of the taproot were compared in recombinant inbred lines from an initial cross between cultivated (Lactuca sativa) and wild (Lactuca serriola) lettuce. Lines with the QTL for more deep laterals at the tip of the taproot appear to benefit from greater water availability, i.e., they had higher shoot biomass, deeper soil water extraction, and greater discrimination for 13C. A marker-assisted breeding program was initiated to introgress this QTL region in L. sativa, with the potential for allowing irrigation less frequently and with less water without a negative impact on yield. Information on approaches and strategies for breeding for crop root systems is also presented here and in a review article, including comparison of screening methodologies. (author)

  17. Root Activity distribution of some annual crops under day farming condition using nuclear techniques

    International Nuclear Information System (INIS)

    The distribution of root activity of wheat and bean as well as olive trees were studied by 32P technique under dry farming condition. Injection of carrier free 32 P into soil at three depths from the soil surface around wheat and bean plants showed that about 72% and 98% of the active roots occurred within the depth of 20 cm, respectively. The results also indicated that the roots of the annual crops were sharing the roots of olive in the ploughing layer. Therefore, intensive inter cropping wheat or bean within the olive trees would lead to a water deficit which in turn, affect the growth and yield of olive

  18. Clustering high dimensional data

    DEFF Research Database (Denmark)

    Assent, Ira

    2012-01-01

    for clustering are required. Consequently, recent research has focused on developing techniques and clustering algorithms specifically for high-dimensional data. Still, open research issues remain. Clustering is a data mining task devoted to the automatic grouping of data based on mutual similarity. Each cluster......High-dimensional data, i.e., data described by a large number of attributes, pose specific challenges to clustering. The so-called ‘curse of dimensionality’, coined originally to describe the general increase in complexity of various computational problems as dimensionality increases, is known...... groups objects that are similar to one another, whereas dissimilar objects are assigned to different clusters, possibly separating out noise. In this manner, clusters describe the data structure in an unsupervised manner, i.e., without the need for class labels. A number of clustering paradigms exist...

  19. Star clusters and associations

    International Nuclear Information System (INIS)

    All 33 papers presented at the symposium were inputted to INIS. They dealt with open clusters, globular clusters, stellar associations and moving groups, and local kinematics and galactic structures. (E.S.)

  20. Evolved Super Star Clusters in M82

    CERN Document Server

    De Grijs, R; Gallagher, J S

    1999-01-01

    We present high-resolution optical and near-infrared HST observations of two adjacent regions in the fossil starburst region in M82, B1 and B2. Age estimates date the cluster population in the fossil starburst between ~2 x 10^8 and ~10 x 10^9 years, assuming solar metallicity. The star cluster population in B2 is more heavily affected by internal extinction than that in B1. Although our cluster size estimates indicate that they are gravitationally bound, and not unlike Galactic globular clusters, their luminosity distribution is significantly fainter than both super star cluster luminosity functions (LFs) and the Galactic globular cluster LF. This makes them unlikely proto-globular clusters, since their luminosities will fade further before they are of similar age as the Galactic globular cluster population. If the compact H-alpha-bright sources in M82 B are Type II supernova remnants (SNRs), they set an upper limit to the end of the starburst in region B2, about 500 pc from the galaxy's core, of ~50 Myr. Reg...

  1. STELLAR ENCOUNTER RATE IN GALACTIC GLOBULAR CLUSTERS

    Energy Technology Data Exchange (ETDEWEB)

    Bahramian, Arash; Heinke, Craig O.; Sivakoff, Gregory R.; Gladstone, Jeanette C., E-mail: bahramia@ualberta.ca [Department of Physics, University of Alberta, CCIS 4-183, Edmonton, AB, T5K 1V4 (Canada)

    2013-04-01

    The high stellar densities in the cores of globular clusters cause significant stellar interactions. These stellar interactions can produce close binary mass-transferring systems involving compact objects and their progeny, such as X-ray binaries and radio millisecond pulsars. Comparing the numbers of these systems and interaction rates in different clusters drives our understanding of how cluster parameters affect the production of close binaries. In this paper we estimate stellar encounter rates ({Gamma}) for 124 Galactic globular clusters based on observational data as opposed to the methods previously employed, which assumed 'King-model' profiles for all clusters. By deprojecting cluster surface brightness profiles to estimate luminosity density profiles, we treat 'King-model' and 'core-collapsed' clusters in the same way. In addition, we use Monte Carlo simulations to investigate the effects of uncertainties in various observational parameters (distance, reddening, surface brightness) on {Gamma}, producing the first catalog of globular cluster stellar encounter rates with estimated errors. Comparing our results with published observations of likely products of stellar interactions (numbers of X-ray binaries, numbers of radio millisecond pulsars, and {gamma}-ray luminosity) we find both clear correlations and some differences with published results.

  2. A Novel Benchmark K-Means Clustering on Continuous Data

    OpenAIRE

    Prasanna, K.; M. Sankara Prasanna Kumar; G. Surya Narayana

    2011-01-01

    Cluster analysis is one of the prominent techniques in the field of data mining and k-means is one of the most well known popular and partitioned based clustering algorithms. K-means clusteringalgorithm is widely used in clustering. The performance of k-means algorithm will affect when clustering the continuous data. In this paper, a novel approach for performing k-means clustering on continuous data is proposed. It organizes all the continuous data sets in a sorted structure such that one ca...

  3. Thermodynamics of confined gallium clusters

    International Nuclear Information System (INIS)

    We report the results of ab initio molecular dynamics simulations of Ga13 and Ga17 clusters confined inside carbon nanotubes with different diameters. The cluster-tube interaction is simulated by the Lennard–Jones (LJ) potential. We discuss the geometries, the nature of the bonding and the thermodynamics under confinement. The geometries as well as the isomer spectra of both the clusters are significantly affected. The degree of confinement decides the dimensionality of the clusters. We observe that a number of low-energy isomers appear under moderate confinement while some isomers seen in the free space disappear. Our finite-temperature simulations bring out interesting aspects, namely that the heat capacity curve is flat, even though the ground state is symmetric. Such a flat nature indicates that the phase change is continuous. This effect is due to the restricted phase space available to the system. These observations are supported by the mean square displacement of individual atoms, which are significantly smaller than in free space. The nature of the bonding is found to be approximately jellium-like. Finally we note the relevance of the work to the problem of single file diffusion for the case of the highest confinement. (paper)

  4. [Affective dependency].

    Science.gov (United States)

    Scantamburlo, G; Pitchot, W; Ansseau, M

    2013-01-01

    Affective dependency is characterized by emotional distress (insecure attachment) and dependency to another person with a low self-esteem and reassurance need. The paper proposes a reflection on the definition of emotional dependency and the confusion caused by various denominations. Overprotective and authoritarian parenting, cultural and socio-environmental factors may contribute to the development of dependent personality. Psychological epigenetic factors, such as early socio-emotional trauma could on neuronal circuits in prefronto-limbic regions that are essential for emotional behaviour.We also focus on the interrelations between dependent personality, domestic violence and addictions. The objective for the clinician is to propose a restoration of self-esteem and therapeutic strategies focused on autonomy. PMID:23888587

  5. Melting of clusters

    Energy Technology Data Exchange (ETDEWEB)

    Haberland, H. [Freiburg Univ., Facultat fur Physik (Germany)

    2001-07-01

    An experiment is described which allows to measure the caloric curve of size selected sodium cluster ions. This allows to determine rather easily the melting temperatures, and latent heats in the size range between 55 and 340 atoms per cluster. A more detailed analysis is necessary to show that the cluster Na{sub 147}{sup +} has a negative microcanonical heat capacity, and how to determine the entropy of the cluster from the data. (authors)

  6. Plant root-microbe communication in shaping root microbiomes.

    Science.gov (United States)

    Lareen, Andrew; Burton, Frances; Schäfer, Patrick

    2016-04-01

    A growing body of research is highlighting the impacts root-associated microbial communities can have on plant health and development. These impacts can include changes in yield quantity and quality, timing of key developmental stages and tolerance of biotic and abiotic stresses. With such a range of effects it is clear that understanding the factors that contribute to a plant-beneficial root microbiome may prove advantageous. Increasing demands for food by a growing human population increases the importance and urgency of understanding how microbiomes may be exploited to increase crop yields and reduce losses caused by disease. In addition, climate change effects may require novel approaches to overcoming abiotic stresses such as drought and salinity as well as new emerging diseases. This review discusses current knowledge on the formation and maintenance of root-associated microbial communities and plant-microbe interactions with a particular emphasis on the effect of microbe-microbe interactions on the shape of microbial communities at the root surface. Further, we discuss the potential for root microbiome modification to benefit agriculture and food production. PMID:26729479

  7. Root canal filling: fracture strength of fiber-reinforced composite-restored roots and finite element analysis.

    Science.gov (United States)

    Rippe, Marília Pivetta; Santini, Manuela Favarin; Bier, Carlos Alexandre Souza; Borges, Alexandre Luiz Souto; Valandro, Luiz Felipe

    2013-01-01

    The aims of this study were to evaluate the effect of root canal filling techniques on root fracture resistance and to analyze, by finite element analysis (FEA), the expansion of the endodontic sealer in two different root canal techniques. Thirty single-rooted human teeth were instrumented with rotary files to a standardized working length of 14 mm. The specimens were embedded in acrylic resin using plastic cylinders as molds, and allocated into 3 groups (n=10): G(lateral) - lateral condensation; G(single-cone) - single cone; G(tagger) - Tagger's hybrid technique. The root canals were prepared to a length of 11 mm with the #3 preparation bur of a tapered glass fiber-reinforced composite post system. All roots received glass fiber posts, which were adhesively cemented and a composite resin core was built. All groups were subjected to a fracture strength test (1 mm/min, 45°). Data were analyzed statistically by one-way ANOVA with a significance level of 5%. FEA was performed using two models: one simulated lateral condensation and Tagger's hybrid technique, and the other one simulated the single-cone technique. The second model was designed with an amount of gutta-percha two times smaller and a sealer layer two times thicker than the first model. The results were analyzed using von Mises stress criteria. One-way ANOVA indicated that the root canal filling technique affected the fracture strength (p=0.004). The G(lateral) and G(tagger) produced similar fracture strength values, while G(single-cone) showed the lowest values. The FEA showed that the single-cone model generated higher stress in the root canal walls. Sealer thickness seems to influence the fracture strength of restored endodontically treated teeth. PMID:24474359

  8. Root Associated Bacteria – Friends or Enemies? A Review

    Directory of Open Access Journals (Sweden)

    Gabriela Mihalache

    2015-10-01

    Full Text Available Plant roots, due to their exudates, represent important ecological niches for bacteria, which can influence the plant growth by their both beneficial and deleterious effects. The positive effects of bacteria interaction with the plants roots consist in facilitating the nutrient uptake (N, P, producing phytohormones, enhancing their resistance to biotic and abiotic factors such as pathogenic fungi and bacteria, extreme temperatures, heavy metals, salinity. Regarding the harmful effects of bacteria on plants growth, production of phytotoxins, competition for nutrients or inducing diseases or even plants death represents examples of mechanisms by which bacteria can affect in a negative manner the growth of the plants.

  9. Ganglioneuroma of Lumbar Nerve Root: A Case Report

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Min Hye; Lee, Seung Hun; Joo, Kyung Bin; Jang, Ki Seok [Dept. of Hanyang University Seoul Hospital, Seoul (Korea, Republic of); Bae, Ji Yoon [Dept. of Pathology, National Police Hospital, Seoul (Korea, Republic of)

    2013-02-15

    Ganglioneuroma is a rare, benign, slow-growing, well-differentiated tumor consisting of ganglion cells and Schwann cells. Ganglioneuromas originate from neural crest cells and can affect any part of the sympathetic tissue from the skull base to the pelvis. However, ganglioneuroma occurring in the nerve root is extremely rare. We describe a 50-year-old man with ganglioneuroma involving the right 5th lumbar nerve root. The ganglioneuroma showed intermediate signal intensity on the T1-weighted image and high signal intensity on the T2-weighted image with homogeneous enhancement on the gadolinium-enhanced T1-weighted image.

  10. Descendant root volume varies as a function of root type: estimation of root biomass lost during uprooting in Pinus pinaster

    OpenAIRE

    Danjon, Frédéric; Caplan, Joshua S.; Fortin, Mathieu; Meredieu, Céline

    2013-01-01

    Root systems of woody plants generally display a strong relationship between the cross-sectional area or cross-sectional diameter (CSD) of a root and the dry weight of biomass (DWd) or root volume (Vd) that has grown (i.e., is descendent) from a point. Specification of this relationship allows one to quantify root architectural patterns and estimate the amount of material lost when root systems are extracted from the soil. However, specifications of this relationship generally do not account ...

  11. Multireference Coupled Cluster Ansatz

    OpenAIRE

    Jeziorski, Bogumil

    2010-01-01

    Abstract The origin of the multireference coupled cluster Ansatz for the wave function and the wave operator, discovered in Quantum Theory Project in 1981, is presented from the historical perspective. Various methods of obtaining the cluster amplitudes - both state universal and state selective are critically reviewed and further prospects of using the multireference coupled cluster Ansatz in electronic structure theory are briefly discussed.

  12. Quantum Annealing for Clustering

    OpenAIRE

    Kurihara, Kenichi; Tanaka, Shu; Miyashita, Seiji

    2014-01-01

    This paper studies quantum annealing (QA) for clustering, which can be seen as an extension of simulated annealing (SA). We derive a QA algorithm for clustering and propose an annealing schedule, which is crucial in practice. Experiments show the proposed QA algorithm finds better clustering assignments than SA. Furthermore, QA is as easy as SA to implement.

  13. The Durban Auto Cluster

    DEFF Research Database (Denmark)

    Lorentzen, Jochen; Robbins, Glen; Barnes, Justin

    2004-01-01

    The paper describes the formation of the Durban Auto Cluster in the context of trade liberalization. It argues that the improvement of operational competitiveness of firms in the cluster is prominently due to joint action. It tests this proposition by comparing the gains from cluster activities i...

  14. Relational aspects of clusters

    DEFF Research Database (Denmark)

    Gjerding, Allan Næs

    The present paper is the first preliminary account of a project being planned for 2013, focussing on the development of the biomedico cluster in North Denmark. The project focusses on the relational capabilities of the cluster in terms of a number of organizational roles which are argued to be...... necessary for the development and growth of the upcoming cluster in question....

  15. Minimalist's linux cluster

    International Nuclear Information System (INIS)

    Using barebone PC components and NIC's, we construct a linux cluster which has 2-dimensional mesh structure. This cluster has smaller footprint, is less expensive, and use less power compared to conventional linux cluster. Here, we report our experience in building such a machine and discuss our current lattice project on the machine

  16. Hormonal response and root architecture in Arabidopsis thaliana subjected to heavy metals

    Directory of Open Access Journals (Sweden)

    Antonella Vitti

    2014-05-01

    Full Text Available In this work, specific concentrations of cadmium, copper and zinc in double combination, were supplied for 12 days to growing seedlings of the model species Arabidopsis thaliana. Metal accumulation was measured in roots and shoots. Microscopic analyses revealed that root morphology was affected by metals, and that the root and shoot levels of indole-3-acetic acid, trans-zeatin riboside and dihydrozeatin riboside varied accordingly. Minor modifications in gibberellic acid levels occurred in the Zinc treatments, whereas abscisic acid level did not change after the exposition to metals. Reverse transcription polymerase chain reaction analysis of some genes involved in auxin and cytokinin synthesis (AtAAO, AtNIT and AtIPT revealed that their expression were not affected by metal treatments. The root morphological alterations that resulted in an increased surface area, due to the formation of root hairs and lateral roots, could be signs of the response to metal stress in terms of a functionally-addressed reorientation of root growth. The root system plasticity observed could be important for better understanding the manner in which the root architecture is shaped by environmental and hormonal stimuli.

  17. Fine root dynamics of mature European beech (Fagus sylvatica L.) as influenced by elevated ozone concentrations

    International Nuclear Information System (INIS)

    Fine root dynamics (diameter < 1 mm) in mature Fagus sylvatica, with the canopies exposed to ambient or twice-ambient ozone concentrations, were investigated throughout 2004. The focus was on the seasonal timing and extent of fine root dynamics (growth, mortality) in relation to the soil environment (water content, temperature). Under ambient ozone concentrations, a significant relationship was found between fine root turnover and soil environmental changes indicating accelerated fine root turnover under favourable soil conditions. In contrast, under elevated ozone, this relationship vanished as the result of an altered temporal pattern of fine root growth. Fine root survival and turnover rate did not differ significantly between the different ozone regimes, although a delay in current-year fine root shedding was found under the elevated ozone concentrations. The data indicate that increasing tropospheric ozone levels can alter the timing of fine root turnover in mature F. sylvatica but do not affect the turnover rate. - Doubling of ozone concentrations in mature European beech affected the seasonal timing of fine root turnover rather than the turnover rate.

  18. Cluster Physics with Merging Galaxy Clusters

    Directory of Open Access Journals (Sweden)

    Sandor M. Molnar

    2016-02-01

    Full Text Available Collisions between galaxy clusters provide a unique opportunity to study matter in a parameter space which cannot be explored in our laboratories on Earth. In the standard LCDM model, where the total density is dominated by the cosmological constant ($Lambda$ and the matter density by cold dark matter (CDM, structure formation is hierarchical, and clusters grow mostly by merging.Mergers of two massive clusters are the most energetic events in the universe after the Big Bang,hence they provide a unique laboratory to study cluster physics.The two main mass components in clusters behave differently during collisions:the dark matter is nearly collisionless, responding only to gravity, while the gas is subject to pressure forces and dissipation, and shocks and turbulenceare developed during collisions. In the present contribution we review the different methods used to derive the physical properties of merging clusters. Different physical processes leave their signatures on different wavelengths, thusour review is based on a multifrequency analysis. In principle, the best way to analyze multifrequency observations of merging clustersis to model them using N-body/HYDRO numerical simulations. We discuss the results of such detailed analyses.New high spatial and spectral resolution ground and space based telescopeswill come online in the near future. Motivated by these new opportunities,we briefly discuss methods which will be feasible in the near future in studying merging clusters.

  19. Clustering high dimensional data using subspace and projected clustering algorithms

    OpenAIRE

    Rahmat Widia Sembiring; Jasni Mohamad Zain; Abdullah Embong

    2010-01-01

    Problem statement: Clustering has a number of techniques that have been developed in statistics, pattern recognition, data mining, and other fields. Subspace clustering enumerates clusters of objects in all subspaces of a dataset. It tends to produce many over lapping clusters. Approach: Subspace clustering and projected clustering are research areas for clustering in high dimensional spaces. In this research we experiment three clustering oriented algorithms, PROCLUS, P3C and STATPC. Results...

  20. Effects of different irrigation methods on micro-environments and root distribution in winter wheat ifelds

    Institute of Scientific and Technical Information of China (English)

    L Guo-hua; SONG Ji-qing; BAI Wen-bo; WU Yong-feng; LIU Yuan; KANG Yao-hu

    2015-01-01

    The irrigation method used in winter wheat ifelds affects micro-environment factors, such as relative humidity (RH) within canopy, soil temperature, topsoil bulk density, soil matric potential, and soil nutrients, and these changes may affect plant root growth. An experiment was carried out to explore the effects of irrigation method on micro-environments and root distribution in a winter wheat ifeld in the 2007–2008 and 2008–2009 growing seasons. The results showed that border irrigation (BI), sprinkler irrigation (SI), and surface drip irrigation (SDI) had no signiifcant effects on soil temperature. Topsoil bulk density, RH within the canopy, soil available N distribution, and soil matric potential were signiifcantly affected by the three treatments. The change in soil matric potential was the key reason for the altered root proifle distribution patterns. Additional y, more ifne roots were produced in the BI treatment when soil water content was low and topsoil bulk density was high. Root growth was most stimulated in the top soil layers and inhibited in the deep layers in the SDI treatment, fol owed by SI and BI, which was due to the different water application frequencies. As a result, the root proifle distribution differed, depending on the irrigation method used. The root distribution pattern changes could be described by the power level variation in the exponential function. A good knowledge of root distribution patterns is important when attempting to model water and nutrient movements and when studying soil-plant interactions.

  1. Effect of soil deep tillage on root activity and vertical distribution

    International Nuclear Information System (INIS)

    Deep tillage (broke plough pan) and cultivation before winter coming (cut off some roots in shallow soil layer)could obviously affect the mass root activity of wheat and it's spatial distribution. Deep tillage improved the physical and chemical properties of the soil, so was the root living condition. Comparison with the CK (conventional tillage), the spatial distribution of root activity intend to deepen and the root activity in deep soil layer was stronger with the soil of deep tillage, which was beneficial to delay the senescence of plant and increase grain yield. It was also found that cultivation before winter coming could improve the mass root activity in subsoil layer (below 20 cm), and its effect was the same as that of deep tillage

  2. Inheritance and gene expression of a root-growth inhibiting mutant in rice (Oryza sativa L.)

    International Nuclear Information System (INIS)

    Full text: A root-growth inhibiting mutant was induced in the dwarf mutant line, 'Fukei 71', through ethylene-imine. The mutant is characterised by the excessive inhibition of both seminal and crown roots elongation just after germination, although its shoots grow nearly normal. To study the genetics, the mutant was crossed with its original line 'Fukei 71' and some other normal cultivars. Results show that the root-growth inhibition is controlled by a recessive gene (rt), independent of the dwarf gene, d-50(t) locus in Fukei 71. For elucidating the gene action on root morphogenesis, histological and cytological experiments were carried out using a longitudinal and transverse thin section of seminal and/or crown root tips. Observations suggest that the rt gene affects the normal formation of the epidermal system which is differentiated from the protoderm of the root apical meristem. (author)

  3. Minimal Nielsen Root Classes and Roots of Liftings

    Directory of Open Access Journals (Sweden)

    Marcio Colombo Fenille

    2009-01-01

    Full Text Available Given a continuous map f:K→M from a 2-dimensional CW complex into a closed surface, the Nielsen root number N(f and the minimal number of roots μ(f of f satisfy N(f≤μ(f. But, there is a number μC(f associated to each Nielsen root class of f, and an important problem is to know when μ(f=μC(fN(f. In addition to investigate this problem, we determine a relationship between μ(f and μ(f˜, when f˜ is a lifting of f through a covering space, and we find a connection between this problems, with which we answer several questions related to them when the range of the maps is the projective plane.

  4. Dosage effect of the short arm of chromosome 1 of rye on root morphology and anatomy in bread wheat

    OpenAIRE

    Sharma, Sundrish; DeMason, Darleen A.; Ehdaie, Bahman; Lukaszewski, Adam J.; Waines, J. Giles

    2010-01-01

    The spontaneous translocation of the short arm of chromosome 1 of rye (1RS) in bread wheat is associated with higher root biomass and grain yield. Recent studies have confirmed the presence of QTL for different root morphological traits on the 1RS arm in bread wheat. This study was conducted to address two questions in wheat root genetics. First, does the presence of the 1RS arm in bread wheat affect its root anatomy? Second, how does root morphology and anatomy of bread wheat respond to diff...

  5. Short-term physiological changes in roots and leaves of sugarcane varieties exposed to H2O2 in root medium.

    Science.gov (United States)

    Silva, Karina I; Sales, Cristina R G; Marchiori, Paulo E R; Silveira, Neidiquele M; Machado, Eduardo C; Ribeiro, Rafael V

    2015-04-01

    The aim of this study was to evaluate the differential sensitivity of sugarcane genotypes to H2O2 in root medium. As a hypothesis, the drought tolerant genotype would be able to minimize the oxidative damage and maintain the water transport from roots to shoots, reducing the negative effects on photosynthesis. The sugarcane genotypes IACSP94-2094 (drought tolerant) and IACSP94-2101 (drought sensitive) were grown in a growth chamber and exposed to three levels of H2O2 in nutrient solution: control; 3 mmol L(-1) and 80 mmol L(-1). Leaf gas exchange, photochemical activity, root hydraulic conductance (Lr) and antioxidant metabolism in both roots and leaves were evaluated after 15 min of treatment with H2O2. Although, root hydraulic conductance, stomatal aperture, apparent electron transport rate and instantaneous carboxylation efficiency have been reduced by H2O2 in both genotypes, IACSP94-2094 presented higher values of those variables as compared to IACSP94-2101. There was a significant genotypic variation in relation to the physiological responses of sugarcane to increasing H2O2 in root tissues, being root changes associated with modifications in plant shoots. IACSP94-2094 presented a root antioxidant system more effective against H2O2 in root medium, regardless H2O2 concentration. Under low H2O2 concentration, water transport and leaf gas exchange of IACSP94-2094 were less affected as compared to IACSP94-2101. Under high H2O2 concentration, the lower sensitivity of IACSP94-2094 was associated with increases in superoxide dismutase activity in roots and leaves and increases in catalase activity in roots. In conclusion, we propose a general model of sugarcane reaction to H2O2, linking root and shoot physiological responses. PMID:25703773

  6. Genetics Home Reference: myopathy with deficiency of iron-sulfur cluster assembly enzyme

    Science.gov (United States)

    ... myopathy with deficiency of iron-sulfur cluster assembly enzyme Enable Javascript to view the expand/collapse boxes. ... Myopathy with deficiency of iron-sulfur cluster assembly enzyme is an inherited disorder that primarily affects muscles ...

  7. Advances in experimental methods for root system architecture and root development

    Institute of Scientific and Technical Information of China (English)

    Jun-bang Wang; Xiu-juan Zhang; Chu Wu

    2015-01-01

    Plant roots play important roles in acquisition of water and nutrients, storage, anchoring, transport, and symbiosis with soil microorganisms, thus quantitative researches on root developmental processes are essential to understand root functions and root turnover in ecosystems, and at the same time such researches are the most difficult because roots are hidden underground. Therefore, how to investigate efficiently root functions and root dynamics is the core aspect in underground ecology. In this article, we reviewed some experimental methods used in root resear-ches on root development and root system architecture, and summarized the advantages and shortages of these meth-ods. Based on the analyses, we proposed three new ways to more understand root processes: (1) new experimental materials for root development; (2) a new observatory system comprised of multiple components, including many observatory windows installed in field, analysis software, and automatic data transport devices; (3) new techniques used to analyze quantitatively functional roots.

  8. Polynuclear technetium halide clusters

    International Nuclear Information System (INIS)

    Development of chemistry of polynuclear technetium halide clusters in works devoted to synthesis, structure and investigation of their chemical and physical properties is considered. The role of academician V.I. Spitsyn as an initiator of investigation of polynuclear technetium halide clusters in the Institute of Physical Chemistry of Academy of Science of USSR is noted. Reactions and stability of cluster halides, their molecular and electronic structures are analyzed. Prospects of development of polynuclear technetium halide clusters chemistry as a direction being on the junction of cluster chemistry and theory of metal-metal multiple bonds are appreciated

  9. Cluster analysis for applications

    CERN Document Server

    Anderberg, Michael R

    1973-01-01

    Cluster Analysis for Applications deals with methods and various applications of cluster analysis. Topics covered range from variables and scales to measures of association among variables and among data units. Conceptual problems in cluster analysis are discussed, along with hierarchical and non-hierarchical clustering methods. The necessary elements of data analysis, statistics, cluster analysis, and computer implementation are integrated vertically to cover the complete path from raw data to a finished analysis.Comprised of 10 chapters, this book begins with an introduction to the subject o

  10. Root status and future developments

    International Nuclear Information System (INIS)

    In this talk the authors review the major additions and improvements made to the ROOT system in the last 18 months and present their plans for future developments. The additions and improvements range from modifications to the I/O sub-system to allow users to save and restore objects of classes that have not been instrumented by special ROOT macros, to the addition of a geometry package designed for building, browsing, tracking and visualizing detector geometries. Other improvements include enhancements to the quick analysis sub-system (TTree::Draw()), the addition of classes that allow inter-file object references (TRef, TRefArray), better support for templates and STL classes, amelioration of the Automatic Script Compiler and the incorporation of new fitting and mathematical tools. Efforts have also been made to increase the modularity of the ROOT system with the introduction of more abstract interfaces and the development of a plug-in manager. In the near future, they intend to continue the development of PROOF and its interfacing with GRID environments. They plan on providing an interface between Geant3, Geant4 and Fluka and the new geometry package. The ROOT-GUI classes will finally be available on Windows and they plan to release a GUI inspector and builder. In the last year, ROOT has drawn the endorsement of additional experiments and institutions. It is now officially supported by CERN and used as key I/O component by the LCG project

  11. Radiopacity of root filling materials

    International Nuclear Information System (INIS)

    A method for measuring the radiopacity of root filling materials is described. Direct measurements were made of the optic density values of the materials in comparison with a standard curve relating optic density to the thickness of an aluminium step wedge exposed simultaneously. By proper selection of film and conditions for exposure and development, it was possible to obtain a near-linear standard curve which added to the safety and reproducibility of the method. The technique of radiographic assessment was modified from clinical procedures in evaluating the obturation in radiographs, and it was aimed at detecting slits or voids between the dental wall and the filling material. This radiographic assessment of potensial leakage was compared with actual in vitro lekage of dye (basic fuchsin) into the roots of filled teeth. The result of the investigation show that root filling materials display a very wide range of radiopacity, from less than 3 mm to more than 12 mm of aluminium. It also seem that tooth roots that appear to be well obturated by radiographic evaluation, stand a good chance of beeing resistant to leakage in vitro, and that the type of filling material rather than its radiographic appearance, determines the susceptibility of the filled tooth to leakage in vitro. As an appendix the report contains a survey of radiopaque additives in root filling materials

  12. Canopy Composition and Topographic Controls on Root Cohesion in Landslide-Prone Terrain

    Science.gov (United States)

    Hales, T. C.; Ford, C. R.; Hwang, T.; Vose, J.; Band, L. E.

    2009-12-01

    Steep, forested landscapes are commonly the source of devastating shallow landslides and debris flows. The magnitude and frequency of these slides is dependent on the distribution of steep slopes, the frequency of prolonged and/or intense precipitation, and the resistive properties of soil and roots. Most studies of the human influence on shallow landslide frequency focus on the effects of forestry and associated road building. Humans also influence the species composition of forests through management and introductions of exotic species. Forest composition affects the magnitude of root reinforcement of largely cohesionless colluvial soils that resist landsliding. We investigated how topographically controlled changes in forest composition affected the distribution of root reinforcement along a catenery sequence in a forested catchment, southern Appalachian Mountains, North Carolina. The magnitude of reinforcement is estimated based on the vertical distribution and tensile strength of roots from soil pits dug downslope of fifteen native woody species. Root tensile strengths from different hardwood tree species were similar and consistently higher than the only native shrub species measured (Rhododendron maximum). Roots were stronger in trees found on noses relative to those in hollows coincident with the variability in cellulose content. This cellulose variability is likely an ecophysiologic response to differences in soil moisture potential along our catena. For all species, roots were concentrated close to the soil surface, with the majority of R. maximum roots located in the shallow, O-horizon. R. maximum had lower mean root cohesion than trees because of a lower root tensile force and a shallow rooting structure. Our results highlight the need to quantify how changes in canopy composition, particularly the expansion of R. maximum due to fire suppression, affect shallow landslide potential. We suggest that a combination of simple topographic analysis and leaf

  13. Role of Cytokinin and Auxin in Shaping Root Architecture: Regulating Vascular Differentiation, Lateral Root Initiation, Root Apical Dominance and Root Gravitropism

    OpenAIRE

    Aloni, R; ALONI, E.; Langhans, M.; ULLRICH, C. I.

    2006-01-01

    • Background and Aims Development and architecture of plant roots are regulated by phytohormones. Cytokinin (CK), synthesized in the root cap, promotes cytokinesis, vascular cambium sensitivity, vascular differentiation and root apical dominance. Auxin (indole-3-acetic acid, IAA), produced in young shoot organs, promotes root development and induces vascular differentiation. Both IAA and CK regulate root gravitropism. The aims of this study were to analyse the hormonal mechanisms that induce ...

  14. Planetary systems in star clusters

    CERN Document Server

    Kouwenhoven, M B N; Cai, Maxwell Xu; Spurzem, Rainer

    2016-01-01

    Thousands of confirmed and candidate exoplanets have been identified in recent years. Consequently, theoretical research on the formation and dynamical evolution of planetary systems has seen a boost, and the processes of planet-planet scattering, secular evolution, and interaction between planets and gas/debris disks have been well-studied. Almost all of this work has focused on the formation and evolution of isolated planetary systems, and neglect the effect of external influences, such as the gravitational interaction with neighbouring stars. Most stars, however, form in clustered environments that either quickly disperse, or evolve into open clusters. Under these conditions, young planetary systems experience frequent close encounters with other stars, at least during the first 1-10 Myr, which affects planets orbiting at any period range, as well as their debris structures.

  15. Survey on Text Document Clustering

    OpenAIRE

    M.Thangamani; Dr.P.Thangaraj

    2010-01-01

    Document clustering is also referred as text clustering, and its concept is merely equal to data clustering. It is hardly difficult to find the selective information from an ‘N’number of series information, so that document clustering came into picture. Basically cluster means a group of similar data, document clustering means segregating the data into different groups of similar data. Clustering can be of mathematical, statistical or numerical domain. Clustering is a fundamental data analysi...

  16. Unconventional methods for clustering

    Science.gov (United States)

    Kotyrba, Martin

    2016-06-01

    Cluster analysis or clustering is a task of grouping a set of objects in such a way that objects in the same group (called a cluster) are more similar (in some sense or another) to each other than to those in other groups (clusters). It is the main task of exploratory data mining and a common technique for statistical data analysis used in many fields, including machine learning, pattern recognition, image analysis, information retrieval, and bioinformatics. The topic of this paper is one of the modern methods of clustering namely SOM (Self Organising Map). The paper describes the theory needed to understand the principle of clustering and descriptions of algorithm used with clustering in our experiments.

  17. Clusters in nuclei

    CERN Document Server

    Beck, Christian

    Following the pioneering discovery of alpha clustering and of molecular resonances, the field of nuclear clustering is today one of those domains of heavy-ion nuclear physics that faces the greatest challenges, yet also contains the greatest opportunities. After many summer schools and workshops, in particular over the last decade, the community of nuclear molecular physicists has decided to collaborate in producing a comprehensive collection of lectures and tutorial reviews covering the field. This third volume follows the successful Lect. Notes Phys. 818 (Vol. 1) and 848 (Vol. 2), and comprises six extensive lectures covering the following topics:  - Gamma Rays and Molecular Structure - Faddeev Equation Approach for Three Cluster Nuclear Reactions - Tomography of the Cluster Structure of Light Nuclei Via Relativistic Dissociation - Clustering Effects Within the Dinuclear Model : From Light to Hyper-heavy Molecules in Dynamical Mean-field Approach - Clusterization in Ternary Fission - Clusters in Light N...

  18. Spatial cluster modelling

    CERN Document Server

    Lawson, Andrew B

    2002-01-01

    Research has generated a number of advances in methods for spatial cluster modelling in recent years, particularly in the area of Bayesian cluster modelling. Along with these advances has come an explosion of interest in the potential applications of this work, especially in epidemiology and genome research. In one integrated volume, this book reviews the state-of-the-art in spatial clustering and spatial cluster modelling, bringing together research and applications previously scattered throughout the literature. It begins with an overview of the field, then presents a series of chapters that illuminate the nature and purpose of cluster modelling within different application areas, including astrophysics, epidemiology, ecology, and imaging. The focus then shifts to methods, with discussions on point and object process modelling, perfect sampling of cluster processes, partitioning in space and space-time, spatial and spatio-temporal process modelling, nonparametric methods for clustering, and spatio-temporal ...

  19. Synergistic growth effect among bacteria recovered from root canal infections

    Directory of Open Access Journals (Sweden)

    Gil Moreira Júnior

    2011-09-01

    Full Text Available The objective of this study was to determine the ecological relationships between bacterial species that colonize infected root canals. Root canal bacteria recovered from one patient with pulp canal necrosis were evaluated in vitro for synergistic and antagonistic activities determined by mono and co-culture growth kinetics and the production of bacteriocin-like substances using the double layer diffusion method. Peptostreptococcus prevotii triggered a significant increase of Fusobacterium nucleatum growth, while the former bacteria did not affect the growth of P. prevotii. The bacterial species did not produce antagonism activity against itself or against any of the other two species. Despite many studies have demonstrated the capability of root canal microorganisms to produce antagonistic substances, these in vitro experimental tests show the synergistic effect of P. prevotii on the growth of F. nucleatum.

  20. Identifying Clusters within R&D Intensive Industries Using Local Spatial Methods

    OpenAIRE

    Kosfeld, Reinhold

    2012-01-01

    In recent times, there has been a renewed interest in cluster policies for supporting industrial and regional development. Prominent economics like Porter and Krugman emphasise the role of clusters in regional competition and show in which way clusters can positively affect competition by increasing productivity and innovation. Because of the linkage between growth and innovation, R&D intensive industries play a crucial role in cluster development strategies. Empirical cluster research has to...

  1. 次氯酸钠冲洗方式、温度和冲洗时间影响根管玷污层的清除效果%Flushing methods, temperature and flushing time of sodium hypochlorite affect the clearance effect on the smear layer of root canal

    Institute of Scientific and Technical Information of China (English)

    后岷红; 陈敏; 李蕾; 张沙沙; 周冬艳; 吴丽更

    2015-01-01

    背景:根管预备中,次氯酸钠根管冲洗液清除玷污层的效果与冲洗液接触时间和面积、冲洗液的量、冲洗液温度、冲洗液浓度、冲洗方式等有关。目的:观察在不同冲洗方式、冲洗温度和冲洗时间下,3%次氯酸钠对根管玷污层的清除效果。方法:收集离体人单根前牙180颗,均采用机动ProTaper进行根管预备,以3%次氯酸钠冲洗根管,根据冲洗方式将其随机均分为根管主动清洗组、被动超声荡洗组和侧方开口冲洗针组3大组,再根据冲洗温度和每更换一根锉后的冲洗时间分别将每大组随机均分为6小组,分别为20℃30 s组、20℃60 s组、37℃30 s组、37℃60 s、60℃30 s组和60℃60 s组。扫描电镜观察各组根管玷污层清除效果。结果与结论:根管主动清洗组玷污层的总体清除效果优于被动超声荡洗组与侧方开口冲洗针组(P <0.05)。每组组内,在时间一定的情况下,60℃组的玷污层清除效果优于37℃组、20℃组(P <0.05);在温度一定的情况下,60 s组的玷污层清除效果优于30 s组(P <0.05);根冠1/3区的玷污层清除效果优于根中1/3区、根尖1/3区(P <0.05)。说明以根管主动清洗方式,采用60℃的3%次氯酸钠清洗60 s清除玷污层的效果最好。%BACKGROUND:In root canal preparation, the clearance effect of sodium hypochlorite for root canal irrigation on the smear layer is associated with the contact time and contact area of irrigation fluid, the amount of irrigation fluid, irrigation fluid temperature, irrigation fluid concentration, flushing methods and so on. OBJECTIVE:To investigate the clearance effect of 3% sodium hypochlorite on the smear layer of root canal under different flushing methods, flushing temperature and flushing time. METHODS:Totaly 180 isolated front teeth with single root were colected and root canal preparation was conducted using motorized ProTaper. The root canal was

  2. Retention of Root Canal Posts

    DEFF Research Database (Denmark)

    Sahafi, A; Benetti, Ana Raquel; Flury, S;

    2015-01-01

    The aim of this study was to investigate the effect of the cement film thickness of a zinc phosphate or a resin cement on retention of untreated and pretreated root canal posts. Prefabricated zirconia posts (CosmoPost: 1.4 mm) and two types of luting cements (a zinc phosphate cement [DeTrey Zinc......] and a self-etch adhesive resin cement [Panavia F2.0]) were used. After removal of the crowns of 360 extracted premolars, canines, or incisors, the root canals were prepared with a parallel-sided drill system to three different final diameters. Half the posts did not receive any pretreatment. The other...... half received tribochemical silicate coating according to the manufacturer's instructions. Posts were then luted in the prepared root canals (n=30 per group). Following water storage at 37°C for seven days, retention of the posts was determined by the pull-out method. Irrespective of the luting cement...

  3. Adventitious Roots and Secondary Metabolism

    Institute of Scientific and Technical Information of China (English)

    Hosakatte Niranjana Murthy; Eun Joo Hahn; Kee Yoeup Paek

    2008-01-01

    Plants are a rich source of valuable secondary metabolites and in the recent years plant cell, tissue and organ cultures have been developed as an important alternative sources for the production of these compounds. Adventitious roots have been successfully induced in many plant species and cultured for the production of high value secondary metabolites of pharmaceutical, nutraceutical and industrial importance. Adoption of elicitation methods have shown improved synthesis of secondary metabolites in adventitious root cultures. Development of large-scale culture methods using bioreactors has opened up feasibilities of production of secondary metabolites at the industrial levels. In the present review we summarize the progress made in recent past in the area of adventitious root cultures for the production of secondary metabolites.

  4. Mobility of large clusters on a semiconductor surface: Kinetic Monte Carlo simulation results

    Science.gov (United States)

    M, Esen; A, T. Tüzemen; M, Ozdemir

    2016-01-01

    The mobility of clusters on a semiconductor surface for various values of cluster size is studied as a function of temperature by kinetic Monte Carlo method. The cluster resides on the surface of a square grid. Kinetic processes such as the diffusion of single particles on the surface, their attachment and detachment to/from clusters, diffusion of particles along cluster edges are considered. The clusters considered in this study consist of 150-6000 atoms per cluster on average. A statistical probability of motion to each direction is assigned to each particle where a particle with four nearest neighbors is assumed to be immobile. The mobility of a cluster is found from the root mean square displacement of the center of mass of the cluster as a function of time. It is found that the diffusion coefficient of clusters goes as D = A(T)Nα where N is the average number of particles in the cluster, A(T) is a temperature-dependent constant and α is a parameter with a value of about -0.64 < α < -0.75. The value of α is found to be independent of cluster sizes and temperature values (170-220 K) considered in this study. As the diffusion along the perimeter of the cluster becomes prohibitive, the exponent approaches a value of -0.5. The diffusion coefficient is found to change by one order of magnitude as a function of cluster size.

  5. Agricultural Clusters in the Netherlands

    NARCIS (Netherlands)

    Schouten, M.A.; Heijman, W.J.M.

    2012-01-01

    Michael Porter was the first to use the term cluster in an economic context. He introduced the term in The Competitive Advantage of Nations (1990). The term cluster is also known as business cluster, industry cluster, competitive cluster or Porterian cluster. This article aims at determining and mea

  6. Efficient hydraulic properties of root systems

    Science.gov (United States)

    Bechmann, Marcel; Schneider, Christoph; Carminati, Andrea; Hildebrandt, Anke

    2013-04-01

    Understanding the mechanisms of ecosystem root water uptake (RWU) is paramount for parameterizing hydrological models. With the increase in computational power it is possible to calculate RWU explicitly up to the single plant scale using physical models. However, application of these models for increasing our understanding of ecosystem root water uptake is hindered by the deficit in knowledge about the detailed hydraulic parameter distribution within root systems. However, those physical models may help us to identify efficient parameterizations and to describe the influence of these hydraulic parameters on RWU profiles. In this research, we investigated the combined influence of root hydraulic parameters and different root topologies on shaping efficient root water uptake. First, we use a conceptual model of simple branching structures to understand the influence of branching location and transitions in root hydraulic properties on the RWU patterns in typical sub root structures. Second, we apply a physical model called "aRoot" to test our conclusions on complex root system architectures of single plants. aRoot calculates the distribution of xylem potential within arbitrary root geometries to satisfy a given water demand depending on the available water in the soil. Redistribution of water within the bulk soil is calculated using the Richards equation. We analyzed results using a measure of uptake efficiency, which describes the effort necessary for transpiration. Simulations with the conceptual model showed that total transpiration in sub root structures is independent of root hydraulic properties over a wide range of hydraulic parameters. On the other hand efficiency of root water uptake depends crucially on distribution hydraulic parameters in line with root topology. At the same time, these parameters shape strongly the distribution of RWU along the roots, and its evolution in time, thus leading to variable individual root water uptake profiles. Calculating

  7. Sensitivity of the "Root Bundle Model" to root mechanical properties and root distribution: Implication for shallow landslide stability.

    Science.gov (United States)

    Schwarz, Massimiliano; Giadrossich, Filippo; Cohen, Denis

    2015-04-01

    Root reinforcement is recognized as an important factor for shallow landslides stability. Due to the complexity of root reinforcement mechanisms and the heterogeneity of the root-soil system, the estimation of parameters used in root reinforcement models is difficult, time consuming, and often highly uncertain. For practical applications, it is necessary to focus on the estimation of the most relevant parameters. The objective of the present contribution is to review the state of the art in the development of root reinforcement models and to discuss the sensitivity of the "Root Bundle Model" (RBM) when considering the variability of root mechanical properties and the heterogeneity of root distributions. The RBM is a strain-step loading fiber bundle model extended to include the mechanical and geometrical properties of roots. The model allows the calculation of the force-displacement behavior of a root bundle. In view of new results of field pullout tests performed on coarse roots of spruce (Picea abies) and considering a consistent dataset of root distribution of alpine tree species, we quantify the sensitivity of the RBM and the uncertainty associated with the most important input parameters. Preliminary results show that the extrapolation of force-diameter values from incomplete datasets (i.e., when only small roots are tested and values for coarse roots are extrapolated) may result in considerable errors. In particular, in the case of distributions with root diameters larger than 5 mm, root reinforcement tends to be dominated by coarse roots and their mechanical properties need to be quantified. In addition to the results of the model sensitivity, we present a possible best-practice method for the quantification of root reinforcement in view of its application to slope stability calculations and implementations in numerical models.

  8. How does real affect affect affect recognition in speech?

    NARCIS (Netherlands)

    Truong, Khiet Phuong

    2009-01-01

    The aim of the research described in this thesis was to develop speech-based affect recognition systems that can deal with spontaneous (‘real’) affect instead of acted affect. Several affect recognition experiments with spontaneous affective speech data were carried out to investigate what combinati

  9. Assessing biochar ecotoxicology for soil amendment by root phytotoxicity bioassays.

    Science.gov (United States)

    Visioli, Giovanna; Conti, Federica D; Menta, Cristina; Bandiera, Marianna; Malcevschi, Alessio; Jones, Davey L; Vamerali, Teofilo

    2016-03-01

    Soil amendment with biochar has been proposed as effective in improving agricultural land fertility and carbon sequestration, although the characterisation and certification of biochar quality are still crucial for widespread acceptance for agronomic purposes. We describe here the effects of four biochars (conifer and poplar wood, grape marc, wheat straw) at increasing application rates (0.5, 1, 2, 5, 10, 20, 50% w/w) on both germination and root elongation of Cucumis sativus L., Lepidium sativum L. and Sorghum saccharatum Moench. The tested biochars varied in chemical properties, depending on the type and quality of the initial feedstock batch, polycyclic aromatic hydrocarbons (PAHs) being high in conifer and wheat straw, Cd in poplar and Cu in grape marc. We demonstrate that electrical conductivity and Cu negatively affected both germination and root elongation at ≥5% rate biochar, together with Zn at ≥10% and elevated pH at ≥20%. In all species, germination was less sensitive than root elongation, strongly decreasing at very high rates of chars from grape marc (>10%) and wheat straw (>50%), whereas root length was already affected at 0.5% of conifer and poplar in cucumber and sorghum, with marked impairment in all chars at >5%. As a general interpretation, we propose here logarithmic model for robust root phytotoxicity in sorghum, based on biochar Zn content, which explains 66% of variability over the whole dosage range tested. We conclude that metal contamination is a crucial quality parameter for biochar safety, and that root elongation represents a stable test for assessing phytotoxicity at recommended in-field amendment rates (<1-2%). PMID:26884353

  10. Detrending bootstrap unit root tests

    OpenAIRE

    Smeekes, S.

    2009-01-01

    The role of detrending in bootstrap unit root tests is investigated. When bootstrapping, detrending must not only be done for the construction of the test statistic, but also in the first step of the bootstrap algorithm. It is argued that the two points should be treated separately. Asymptotic validity of sieve bootstrap ADF unit root tests is shown for test statistics based on full sample and recursive OLS and GLS detrending. It is also shown that the detrending method in the first step of t...

  11. Transcriptional and microscopic analyses of citrus stem and root responses to Candidatus Liberibacter asiaticus infection.

    Directory of Open Access Journals (Sweden)

    Valente Aritua

    Full Text Available Huanglongbing (HLB is the most destructive disease that affects citrus worldwide. The disease has been associated with Candidatus Liberibacter. HLB diseased citrus plants develop a multitude of symptoms including zinc and copper deficiencies, blotchy mottle, corky veins, stunting, and twig dieback. Ca. L. asiaticus infection also seriously affects the roots. Previous study focused on gene expression of leaves and fruit to Ca. L. asiaticus infection. In this study, we compared the gene expression levels of stems and roots of healthy plants with those in Ca. L. asiaticus infected plants using microarrays. Affymetrix microarray analysis showed a total of 988 genes were significantly altered in expression, of which 885 were in the stems, and 111 in the roots. Of these, 551 and 56 were up-regulated, while 334 and 55 were down-regulated in the stem and root samples of HLB diseased trees compared to healthy plants, respectively. Dramatic differences in the transcriptional responses were observed between citrus stems and roots to Ca. L. asiaticus infection, with only 8 genes affected in both the roots and stems. The affected genes are involved in diverse cellular functions, including carbohydrate metabolism, cell wall biogenesis, biotic and abiotic stress responses, signaling and transcriptional factors, transportation, cell organization, protein modification and degradation, development, hormone signaling, metal handling, and redox. Microscopy analysis showed the depletion of starch in the roots of the infected plants but not in healthy plants. Collapse and thickening of cell walls were observed in HLB affected roots, but not as severe as in the stems. This study provides insight into the host response of the stems and roots to Ca. L. asiaticus infection.

  12. Uptake and Distribution of Aluminum in Root Apices of Two Rice Varieties under Aluminum Stress

    Directory of Open Access Journals (Sweden)

    MIFTAHUDIN

    2007-09-01

    Full Text Available Aluminum (Al toxicity is the major limiting factor of plant growth and production in acid soils. The target of Al toxicity is the root tip, which affects mainly on root growth inhibition. The aim of this research was to study the uptake and distribution of Al in root apices of two rice varieties IR64 (Al-sensitive and Krowal (Al-tolerant, which were grown on nutrient solution containing 0, 15, 30, 45, and 60 ppm of Al. The root growth was significantly inhibited in both rice varieties at as low as 15 ppm Al concentration. The adventive roots of both varieties showed stunted growth in respons to Al stress. There was no difference in root growth inhibition between both rice varieties as well as among Al concentrations. Al uptake on root apices was qualitatively and quantitatively analyzed. Histochemical staining of roots using hematoxylin showed dark purple color on 1 mm region of Al-treated root apices. Rice var. IR 64 tended to take up more Al in root tip than Krowal did. However, there was no statistically significant difference (p = 0.176 in root Al content of both varieties in response to different concentration and period of Al treatments. Al distribution in root apices was found in the epidermal and subepidermal region in both rice varieties. Based on those results, rice var. Krowal that was previously grouped as Al-tolerant variety has similar root growth and physiological response to Al stress as compared to Al-sensitive variety IR64.

  13. Effects of cations on hormone transport in primary roots of Zea mays

    Science.gov (United States)

    Hasenstein, K. H.; Evans, M. L.

    1988-01-01

    We examined the influence of aluminum and calcium (and certain other cations) on hormone transport in corn roots. When aluminum was applied unilaterally to the caps of 15 mm apical root sections the roots curved strongly away from the aluminum. When aluminum was applied unilaterally to the cap and 3H-indole-3-acetic acid was applied to the basal cut surface twice as much radioactivity (assumed to be IAA) accumulated on the concave side of the curved root as on the convex side. Auxin transport in the apical region of intact roots was preferentially basipetal, with a polarity (basipetal transport divided by acropetal transport) of 6.3. In decapped 5 mm apical root segments, auxin transport was acropetally polar (polarity = 0.63). Application of aluminum to the root cap strongly promoted acropetal transport of auxin reducing polarity from 6.3 to 2.1. Application of calcium to the root cap enhanced basipetal movement of auxin, increasing polarity from 6.3 to 7.6. Application of the calcium chelator, ethylene-glycol-bis-(beta-aminoethylether)-N,N,N',N'-tetraacetic acid, greatly decreased basipetal auxin movement, reducing polarity from 6.3 to 3.7. Transport of label after application of tritiated abscisic acid showed no polarity and was not affected by calcium or aluminum. The results indicate that the root cap is particularly important in maintaining basipetal polarity of auxin transport in primary roots of corn. The induction of root curvature by unilateral application of aluminum or calcium to root caps is likely to result from localized effects of these ions on auxin transport. The findings are discussed relative to the possible role of calcium redistribution in the gravitropic curvature of roots and the possibility of calmodulin involvement in the action of calcium and aluminum on auxin transport.

  14. Regulation of Shoot and Root Development through Mutual Signaling

    Institute of Scientific and Technical Information of China (English)

    Jér(o)me Puig; Germain Pauluzzi; Emmanuel Guiderdoni; Pascal Gantet

    2012-01-01

    Plants adjust their development in relation to the availability of nutrient sources.This necessitates signaling between root and shoot.Aside from the well-known systemic signaling processes mediated by auxin,cytokinin,and sugars,new pathways involving carotenoid-derived hormones have recently been identified.The auxin-responsive MAX pathway controls shoot branching through the biosynthesis of strigolactone in the roots.The BYPASS1 gene affects the production of an as-yet unknown carotenoid-derived substance in roots that promotes shoot development.Novel local and systemic mechanisms that control adaptive root development in response to nitrogen and phosphorus starvation were recently discovered.Notably,the ability of the NITRATE TRANSPORTER 1.1 to transport auxin drew for the first time a functional link between auxin,root development,and nitrate availability in soil.The study of plant response to phosphorus starvation allowed the identification of a systemic mobile miRNA.Deciphering and integrating these signaling pathways at the whole-plant level provide a new perspective for understanding how plants regulate their development in response to environmental cues.

  15. Supplemental root in a mandibular first molar: a rarity

    Directory of Open Access Journals (Sweden)

    Poonam Mahajan

    2011-04-01

    Full Text Available Anatomic variations are common in human dentition. A clear understanding of these variations is very important for success of endodontic treatment. A dentist should be aware of these anatomic variations as this can affect the treatment outcome. A case of endodontic therapy is presented in which inability to locate an anatomically rare supplemental canal of a three rooted mandibular first molar resulted in treatment failure. A 21-year-old female reported with pain and swelling in relation to lower right first molar. An intra oral periapical radiograph revealed 3 roots; the first canal of the mesial root and a canal of one of the distal roots were found to be treated endodontically, which were infraobturated but the canal of the 2nd distal root had not been treated. The radiograph revealed periapical radiolucency and widening of periodontal space. Prior to starting the endodontic treatment the clinician must be aware of the anatomic variations in tooth pulp morphology and also the importance of preoperative radiographs cannot be underscored.

  16. The complex lives of star clusters

    CERN Document Server

    Stevenson, David

    2015-01-01

    As with the author’s recent books Extreme Explosions and Under a Crimson Sun, the complex topic of star clusters is broken down and made accessible with clear links to other areas of astronomy in a language which the non-specialist can easily read and enjoy. The full range of a star cluster's lifespan is depicted, as both globular and open clusters are tracked from birth to eventual death. Why is it some are dense conglomerates of stars while others are looser associations? Are the young, brilliant clusters seen in neighboring galaxies such as the Large Magellanic Cloud, M33 or M82 analogous to the ancient globulars seen in the Milky Way? How will these clusters change as their stars wane and die? More interestingly, how does living in a dense star cluster affect the fates of the stars and any attendant planets that accompany them?   Star clusters form many of the most dazzling objects in the astronomers’ catalogs. Many amateur astronomers are interested in exploring how these objects are created and wh...

  17. Clustering aspects in nuclear structure functions

    CERN Document Server

    Hirai, M; Saito, K; Watanabe, T

    2010-01-01

    For understanding an anomalous nuclear effect experimentally observed for the beryllium-9 nucleus at the Thomas Jefferson National Accelerator Facility (JLab), clustering aspects are studied in structure functions of deep inelastic lepton-nucleus scattering by using momentum distributions calculated in antisymmetrized (or fermionic) molecular dynamics (AMD) and also in a simple shell model for comparison. According to the AMD, the Be-9 nucleus consists of two alpha-like clusters with a surrounding neutron. The clustering produces high-momentum components in nuclear wave functions, which affects nuclear modifications of the structure functions. We investigated whether clustering features could appear in the structure function F_2 of Be-9 along with studies for other light nuclei. We found that nuclear modifications of F_2 are similar in both AMD and shell models within our simple convolution description although there are slight differences in Be-9. It indicates that the anomalous Be-9 result should be explain...

  18. A Clustering Classification of Spare Parts for Improving Inventory Policies

    Science.gov (United States)

    Meri Lumban Raja, Anton; Ai, The Jin; Diar Astanti, Ririn

    2016-02-01

    Inventory policies in a company may consist of storage, control, and replenishment policy. Since the result of common ABC inventory classification can only affect the replenishment policy, we are proposing a clustering based classification technique as a basis for developing inventory policy especially for storage and control policy. Hierarchical clustering procedure is used after clustering variables are defined. Since hierarchical clustering procedure requires metric variables only, therefore a step to convert non-metric variables to metric variables is performed. The clusters resulted from the clustering techniques are analyzed in order to define each cluster characteristics. Then, the inventory policies are determined for each group according to its characteristics. A real data, which consists of 612 items from a local manufacturer's spare part warehouse, are used in the research of this paper to show the applicability of the proposed methodology.

  19. Spatial Scan Statistic: Selecting clusters and generating elliptic clusters

    DEFF Research Database (Denmark)

    Christiansen, Lasse Engbo; Andersen, Jens Strodl

    2004-01-01

    The spatial scan statistic is widely used to search for clusters. This paper shows that the usually applied elimination of overlapping clusters to find secondary clusters is sensitive to smooth changes in the shape of the clusters. We present an algorithm for generation of set of confocal elliptic...... clusters. In addition, we propose a new way to present the information in a given set of clusters based on the significance of the clusters....

  20. Cluster brand as a competitive advantage. Case: Airport cluster Finland

    OpenAIRE

    Väinölä, Lotta-Elviira

    2015-01-01

    Objective of the Study: The objective of this study is to explore the phenomenon of cluster branding. This study investigates cluster brand as a competitive advantage that impacts the success or decline of the cluster. The research questions examine three aspects: (1) cluster branding as a process, (2) the concrete tools that can be used in cluster branding and (3) the perceived benefits of cluster brand. The study aims to produce a generic model for cluster branding, which can be used as...